CN118946279A

CN118946279A - Aerosol-generating article having a low density matrix and a relatively long downstream section

Info

Publication number: CN118946279A
Application number: CN202380031097.XA
Authority: CN
Inventors: E·萨迪拉托雷; H·E·塞尼伊尔马兹; J·乌瑟瑞
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2022-04-12
Filing date: 2023-04-12
Publication date: 2024-11-12

Abstract

An aerosol-generating article is provided, comprising a rod of aerosol-generating substrate. The aerosol-generating article comprises a downstream section arranged downstream of the strip of aerosol-generating substrate. The rod of aerosol-generating substrate comprises tobacco material having a bulk density of less than 350 mg/cc. The downstream section comprises a hollow tubular element abutting the downstream end of the strip of aerosol-generating substrate. The downstream section has a length of at least 40 millimeters.

Description

Aerosol-generating article having a low density matrix and a relatively long downstream section

Technical Field

The present invention relates to an aerosol-generating article comprising an aerosol-generating substrate and being adapted to produce an inhalable aerosol upon heating.

Background

Aerosol-generating articles in which an aerosol-generating substrate, such as a tobacco-containing substrate, is heated rather than combusted are known in the art. Generally, in such heated smoking articles, an aerosol is generated by transferring heat from a heat source to a physically separate aerosol-generating substrate or material that may be positioned in contact with, inside, around or downstream of the heat source. During use of the aerosol-generating article, volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source and entrained in air drawn through the aerosol-generating article. As the released compound cools, the compound condenses to form an aerosol.

A number of prior art documents disclose aerosol-generating devices for consuming aerosol-generating articles. Such devices include, for example, electrically heated aerosol-generating devices in which an aerosol is generated by transferring heat from one or more electric heater elements of the aerosol-generating device to an aerosol-generating substrate of a heated aerosol-generating article. For example, electrically heated aerosol-generating devices have been proposed which comprise an internal heater blade adapted to be inserted into an aerosol-generating substrate. It is also known to use aerosol-generating articles in combination with external heating systems. For example, WO2020/115151 describes the provision of one or more heating elements arranged around the periphery of an aerosol-generating article when the aerosol-generating article is received in a cavity of an aerosol-generating device. As an alternative, an inductively heatable aerosol-generating article is proposed by WO2015/176898, comprising an aerosol-generating substrate and a susceptor arranged within the aerosol-generating substrate.

Aerosol-generating articles in which a tobacco-containing substrate is heated without combustion present many challenges not encountered by conventional smoking articles. First, the tobacco-containing substrate is typically heated to a significantly lower temperature than the temperature reached by the combustion front in a conventional cigarette. This may affect the nicotine release of the tobacco-containing substrate and the delivery of nicotine to the consumer. At the same time, if the heating temperature is increased in an attempt to enhance nicotine delivery, the generated aerosol typically needs to be cooled to a greater extent and faster before it reaches the consumer. However, technical solutions commonly used to cool mainstream smoke in conventional smoking articles (such as providing a high filtration efficiency segment at the mouth end of a cigarette) may have undesirable effects in aerosol-generating articles in which the tobacco-containing substrate is heated without combustion, as they may reduce delivery of nicotine. Accordingly, it is desirable to provide a novel aerosol-generating article that is capable of consistently ensuring that satisfactory aerosol delivery is provided to the consumer.

Disclosure of Invention

In addition, there is a widely recognized need for aerosol-generating articles that are easy to use and have improved utility. For example, it is desirable to provide an aerosol-generating article that can be easily inserted into a heating cavity of an aerosol-generating device, and at the same time can be securely held within the heating cavity such that it does not slip out during use.

It is also desirable to provide an aerosol-generating article which is adapted such that the aerosol-generating substrate may be heated more effectively when the aerosol-generating article is inserted into the heating chamber of the aerosol-generating device, thereby minimizing waste of tobacco material.

The present disclosure relates to an aerosol-generating article. The aerosol-generating article may comprise a strip of aerosol-generating substrate. The aerosol-generating article may comprise a downstream section arranged downstream of the strip of aerosol-generating substrate. The aerosol-generating substrate may comprise tobacco material having a bulk density of less than 350 mg/cc. The downstream section may comprise a hollow tubular element abutting the downstream end of the strip of aerosol-generating substrate. The downstream section may have a length of at least 40 millimeters.

According to the present invention there is provided an aerosol-generating article comprising a rod of aerosol-generating substrate. The aerosol-generating article comprises a downstream section arranged downstream of the strip of aerosol-generating substrate. The rod of aerosol-generating substrate comprises tobacco material having a bulk density of less than 350 mg/cc. The downstream section comprises a hollow tubular element abutting the downstream end of the strip of aerosol-generating substrate. The downstream section has a length of at least 40 millimeters.

The present invention relates to an aerosol-generating article having a rod of aerosol-generating substrate having a relatively low bulk density and a relatively long downstream section. Prior art aerosol-generating articles may have a strip of aerosol-generating substrate having a relatively high bulk density and a short downstream section. The present invention thus provides a significantly different construction than prior art aerosol-generating articles.

The strip of aerosol-generating substrate may generate an aerosol when heated, for example by an aerosol-generating device. If the aerosol is delivered to the user immediately after generation, the resulting generated aerosol may have a high temperature that may be very uncomfortable for the user. Thus, some aerosol-generating articles provide a space for the aerosol to cool after generation and before delivery of the aerosol to a user. In some aerosol-generating articles, a space is provided for cooling between the strip of aerosol-generating substrate and the downstream end of the aerosol-generating article.

Providing a relatively long aerosol-generating article may increase the overall length of the path that the generated aerosol travels within the aerosol-generating article and through the downstream section before the generated aerosol is delivered to the user. Increasing the total length of the path that the aerosol travels before it is delivered to the user may provide more time for the aerosol to cool and reduce the temperature before it is delivered to the user.

During the heating cycle of the article, particularly in the context of being externally heated, the higher density aerosol-generating substrate may not be sufficiently heated and consumed, and may increase the Resistance To Draw (RTD) of the article. Thus, this may result in a proportion of the aerosol-generating substrate not being effectively heated in order to facilitate aerosol generation. This proportion of aerosol-generating substrate may actually be wasted.

Thus, providing both a reduced density substrate and a relatively long downstream section can advantageously provide a cooler aerosol to the user while improving the retention characteristics of the article within the heating device and minimizing substrate wastage. Providing a relatively long downstream section with a hollow tubular element may improve the retention of the aerosol-generating article within the heating chamber of the aerosol-generating device, as a longer portion of the downstream section may be engaged with the heating chamber of the heating device. Providing a relatively low bulk density matrix may minimize the likelihood that a proportion of the aerosol-generating article will not generate aerosol, thereby reducing manufacturing costs and waste. Furthermore, the low density matrix may advantageously heat up faster during use, so that aerosols may be generated faster within the heating cycle of the article.

Thus, it may be desirable to have a strip of low density aerosol-generating substrate with an increased length of the downstream section, for example in order to maximize the proportion of the strip of aerosol-generating substrate that is heated when the aerosol-generating article is inserted into the heating chamber of the aerosol-generating device, while ensuring efficient cooling of the aerosol flowing downstream from the substrate. This in turn may optimize the efficiency of generating aerosol from the strip of aerosol-generating substrate such that the amount of aerosol-generating substrate may be minimized as much as possible without affecting the generation of aerosol and RTD characteristics of the article, which may otherwise be undesirable due to providing a longer strip. The amount of aerosol-generating substrate that is actually wasted as it is not used to generate an aerosol can also be minimized. However, it may also be important to maintain the overall length of the aerosol-generating article so that the article may continue to be used in conjunction with existing aerosol-generating devices. It may also be important that existing machines and packages be used without modification.

An aerosol-generating article according to the invention comprises a strip of aerosol-generating substrate. Furthermore, the aerosol-generating article according to the invention comprises one or more elements arranged downstream of the aerosol-generating substrate. Where present, one or more elements downstream of the strip of aerosol-generating substrate form a downstream section of the aerosol-generating article. An aerosol-generating article according to the invention may comprise one or more elements arranged upstream of the aerosol-generating substrate. Where present, one or more elements upstream of the strip of aerosol-generating substrate form an upstream section of the aerosol-generating article.

The strip of aerosol-generating substrate is preferably defined by a wrapper, such as a rod wrapper.

The strips of aerosol-generating substrate preferably have a length of at least 10 mm. Preferably, the strip of aerosol-generating substrate has a length of at least 15 mm. More preferably, the strip of aerosol-generating substrate has a length of at least 17 mm. Even more preferably, the strip of aerosol-generating substrate has a length of at least 18 mm. Most preferably, the strip of aerosol-generating substrate has a length of at least 20 mm.

The strips of aerosol-generating substrate preferably have a length of less than 40 mm. Preferably, the strips of aerosol-generating substrate have a length of less than 35 mm. More preferably, the strips of aerosol-generating substrate have a length of less than 30 mm.

For example, the strips of aerosol-generating substrate preferably have a length of between 10 and 40 mm, or between 10 and 35 mm, or between 10 and 30 mm, or between 15 and 40 mm, or between 15 and 35 mm, or between 15 and 30 mm, or between 20 and 40 mm, or between 20 and 35 mm, or between 20 and 30 mm.

The strips of aerosol-generating substrate preferably have an outer diameter substantially equal to the outer diameter of the aerosol-generating article.

The "outer diameter of the strip of aerosol-generating substrate" may be calculated as an average of a plurality of measurements of the diameter of the strip of aerosol-generating substrate taken at different positions along the length of the strip of aerosol-generating substrate.

Preferably, the strips of aerosol-generating substrate have an outer diameter of at least about 5mm. More preferably, the strips of aerosol-generating substrate have an outer diameter of at least 5.25 mm. Even more preferably, the strips of aerosol-generating substrate have an outer diameter of at least 5.5 mm.

The strips of aerosol-generating substrate preferably have an outer diameter of less than 8 mm. More preferably, the strips of aerosol-generating substrate have an outer diameter of less than 7.5 mm. Even more preferably, the strips of aerosol-generating substrate have an outer diameter of less than 7 mm.

In general, it has been observed that the smaller the diameter of the rod of aerosol-generating substrate, the lower the temperature required to raise the core temperature of the rod of aerosol-generating substrate such that a sufficient amount of evaporable substance is released from the aerosol-generating substrate to form the desired amount of aerosol. While not wishing to be bound by theory, it is understood that the smaller diameter of the strips of aerosol-generating substrate allows the heat supplied to the aerosol-generating article to penetrate into the entire volume of the aerosol-generating substrate more quickly. However, in case the diameter of the strips of aerosol-generating substrate is too small, the volume to surface ratio of the aerosol-generating substrate becomes less advantageous, as the amount of available aerosol-generating substrate is reduced.

The diameter of the strips of aerosol-generating substrate falling within the ranges described herein is particularly advantageous in terms of a balance between energy consumption and aerosol delivery. This advantage is perceived in particular when an aerosol-generating article comprising a rod of aerosol-generating substrate having a diameter as described herein is used in combination with an external heater arranged around the periphery of the aerosol-generating article. Under such operating conditions, it has been observed that at the core of the strip of aerosol-generating substrate, and generally at the core of the article, less thermal energy is required to achieve a sufficiently high temperature. Thus, when operating at lower temperatures, a desired target temperature at the core of the aerosol-generating substrate may be achieved within a desired reduced time frame and with lower energy consumption.

The use of a rod with a smaller diameter aerosol-generating substrate may also advantageously reduce the total weight of tobacco material required in the aerosol-generating article, while still being able to produce a desired level of aerosol. Thus, the level of waste of tobacco can be reduced.

The ratio between the length of the strip of aerosol-generating substrate and the overall length of the aerosol-generating article is preferably at least 0.20. Preferably, the ratio between the length of the strip of aerosol-generating substrate and the overall length of the aerosol-generating article is at least 0.25. More preferably, the ratio between the length of the strip of aerosol-generating substrate and the overall length of the aerosol-generating article is at least 0.30.

The ratio between the length of the strip of aerosol-generating substrate and the overall length of the aerosol-generating article is preferably less than 0.50. Preferably, the ratio between the length of the strip of aerosol-generating substrate and the overall length of the aerosol-generating article is less than 0.45. More preferably, the ratio between the length of the strip of aerosol-generating substrate and the overall length of the aerosol-generating article is less than 0.40.

In some embodiments, the ratio between the length of the strip of aerosol-generating substrate and the overall length of the aerosol-generating article is from 0.20 to 0.50, preferably from 0.20 to 0.45, more preferably from 0.20 to 0.40. In other embodiments, the ratio between the length of the strip of aerosol-generating substrate and the overall length of the aerosol-generating article is from 0.25 to 0.50, preferably from 0.25 to 0.45, more preferably from 0.25 to 0.40. In a further embodiment, the ratio between the length of the strip of aerosol-generating substrate and the overall length of the aerosol-generating article is from 0.30 to 0.50, preferably from 0.30 to 0.45, more preferably from 0.30 to 0.40. In still further embodiments, the ratio between the length of the strip of aerosol-generating substrate and the overall length of the aerosol-generating article is from 0.30 to 0.50, preferably from 0.30 to 0.45, more preferably from 0.30 to 0.40.

Preferably, the strip of aerosol-generating substrate has a substantially uniform cross-section along the length of the strip. It is particularly preferred that the strips of aerosol-generating substrate have a substantially circular cross-section.

Preferably, the aerosol-generating substrate has a density of at least 100 mg/cc. More preferably, the aerosol-generating substrate has a density of at least 125 mg/cc. More preferably, the aerosol-generating substrate has a density of at least 150 mg/cc. Even more preferably, the aerosol-generating substrate has a density of at least 200 mg/cc.

Preferably, the aerosol-generating substrate has a density of less than 1000 mg/cc. More preferably, the aerosol-generating substrate has a density of less than 800 mg/cc. More preferably, the aerosol-generating substrate has a density of less than 700 mg/cc. More preferably, the aerosol-generating substrate has a density of less than 600 mg/cc. More preferably, the aerosol-generating substrate has a density of less than 500 mg/cc. More preferably, the aerosol-generating substrate has a density of less than 400 mg/cc. More preferably, the aerosol-generating substrate has a density of less than 350 mg/cc. More preferably, the aerosol-generating substrate has a density of less than 345 mg/cc. More preferably, the aerosol-generating substrate has a density of less than 325 mg/cc. More preferably, the aerosol-generating substrate has a density of less than 300 mg/cc. More preferably, the aerosol-generating substrate has a density of less than 290 mg/cc. Even more preferably, the aerosol-generating substrate has a density of less than 280 mg/cc.

For example, the aerosol-generating substrate preferably has a density of from 100 mg/cc to 1000 mg/cc, preferably from 100 mg/cc to 800 mg/cc, more preferably from 100 mg/cc to 700 mg/cc, more preferably from 100 mg/cc to 600 mg/cc, more preferably from 100 mg/cc to 500 mg/cc, even more preferably from 100 mg/cc to 400 mg/cc.

For example, the aerosol-generating substrate preferably has a density of from 100 mg/cc to 350 mg/cc, preferably from 100 mg/cc to 345 mg/cc, preferably from 125 mg/cc to 325 mg/cc, more preferably from 150 mg/cc to 300 mg/cc, more preferably from 150 mg/cc to 290 mg/cc, even more preferably from 200 mg/cc to 280 mg/cc.

The aerosol-generating substrate may comprise tobacco material. The rod of aerosol-generating substrate may comprise tobacco material. The tobacco material may comprise shredded tobacco material. The shredded tobacco material may be in the form of cut filler or tobacco cut filler.

Preferably, the tobacco material has a bulk density of at least 100 mg/cc. More preferably, the tobacco material has a bulk density of at least 125 mg/cc. More preferably, the tobacco material has a bulk density of at least 150 mg/cc. Even more preferably, the tobacco material has a bulk density of at least 200 mg/cc. Preferably, the tobacco material has a bulk density of less than 345 mg/cc. More preferably, the tobacco material has a bulk density of less than 325 mg/cc. Even more preferably, the tobacco material has a bulk density of less than 300 mg/cc. Even more preferably, the tobacco material has a bulk density of less than 290 mg/cc. Even more preferably, the tobacco material has a bulk density of less than 280 mg/cc. For example, the tobacco material may have a bulk density of from 100 mg/cc to 350 mg/cc, preferably from 100 mg/cc to 345 mg/cc, more preferably from 125 mg/cc to 325 mg/cc, more preferably from 150 mg/cc to 300 mg/cc, more preferably from 150 mg/cc to 290 mg/cc, even more preferably from 200 mg/cc to 280 mg/cc.

The term "density" as used herein with respect to an aerosol-generating substrate refers to the bulk density of the aerosol-generating substrate. This may be calculated by measuring the total weight of the aerosol-generating substrate and dividing it by the volume of the strip of aerosol-generating substrate (excluding any wrapper).

The bulk density of the tobacco material in the aerosol-generating substrate may be calculated by dividing the sum of the mass of tobacco material in the rod of aerosol-generating substrate by the volume of aerosol-generating substrate (excluding any wrapper). The mass of tobacco material in the aerosol-generating substrate may be determined by removing the tobacco material from the aerosol-generating substrate and weighing the tobacco material. After conditioning the aerosol-generating substrate according to ISO standard 3402:1999, the bulk density of the tobacco material in the aerosol-generating substrate may be determined.

The aerosol-generating substrate may comprise shredded tobacco material. The strips of aerosol-generating substrate may comprise shredded tobacco material. The shredded tobacco material may be in the form of cut filler or tobacco cut filler. The density of such aerosol-generating substrate or shredded tobacco material may be in accordance with the following.

In certain preferred embodiments, the strips of aerosol-generating substrate comprise shredded tobacco material (e.g. tobacco cut filler) having a density of less than 350 mg/cc, preferably less than 345 mg/cc, preferably less than 325 mg/cc, more preferably less than 300 mg/cc, more preferably less than 290 mg/cc, more preferably less than 280 mg/cc. Preferably, the rod of aerosol-generating substrate comprises shredded tobacco material having a bulk density of at least 100 mg/cc. More preferably, the rod of aerosol-generating substrate comprises shredded tobacco material having a bulk density of at least 125 mg/cc. More preferably, the rod of aerosol-generating substrate comprises shredded tobacco material having a bulk density of at least 150 mg/cc. Even more preferably, the rod of aerosol-generating substrate comprises shredded tobacco material having a bulk density of at least 200 mg/cc. For example, the rod of aerosol-generating substrate may comprise shredded tobacco material having a density of from 100 mg/cc to 350 mg/cc, preferably from 100 mg/cc to 345 mg/cc, preferably from 125 mg/cc to 325 mg/cc, more preferably from 150 mg/cc to 300 mg/cc, more preferably from 150 mg/cc to 290 mg/cc, even more preferably from 200 mg/cc to 280 mg/cc.

Preferably, the RTD of the strip of aerosol-generating substrate is less than about 10 mm H ₂ O. More preferably, the RTD of the strip of aerosol-generating substrate is less than 9mm H ₂ O. Even more preferably, the RTD of the strip of aerosol-generating substrate is less than 8mm H ₂ O.

The RTD of the strip of aerosol-generating substrate is preferably at least 4mm H ₂ O. More preferably, the RTD of the strip of aerosol-generating substrate is at least 5mm H ₂ O. Even more preferably, the RTD of the strip of aerosol-generating substrate is at least 6mm H ₂ O.

In some embodiments, the RTD of the strip of aerosol-generating substrate is from 4 mm H ₂ O to 10 mm H ₂ O, preferably from 5mm H ₂ O to 10 mm H ₂ O, preferably from 6mm H ₂ O to 25 mm H ₂ O. In other embodiments, the RTD of the strip of aerosol-generating substrate is from 4 mm H ₂ O to 20 mm H ₂ O, preferably from 5mm H ₂ O to 18 mm H ₂ O, preferably from 6mm H ₂ O to 16 mm H ₂ O. In further embodiments, the RTD of the strip of aerosol generating substrate is from 4 mm H ₂ O to 15 mm H ₂ O, preferably from 5mm H ₂ O to 14 mm H ₂ O, more preferably from 6mm H ₂ O to 12mm H ₂ O.

The aerosol-generating substrate may be a solid aerosol-generating substrate. Preferably, the aerosol-generating substrate comprises an aerosol-former. The aerosol former may be any suitable known compound or mixture of compounds that aids in forming a dense and stable aerosol in use. The aerosol-former may facilitate substantial resistance of the aerosol to thermal degradation at temperatures applied during typical use of the aerosol-generating article. Suitable aerosol formers are, for example: polyhydric alcohols such as triethylene glycol, 1, 3-butanediol, propylene glycol and glycerol; esters of polyols, such as glycerol mono-, di-or triacetate; aliphatic esters of monocarboxylic, dicarboxylic or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate; and combinations thereof.

Preferably, the aerosol former comprises one or more of glycerol and propylene glycol. The aerosol former may consist of glycerin or propylene glycol or a combination of glycerin and propylene glycol.

Preferably, the aerosol-generating substrate comprises at least 5wt% aerosol-forming agent based on dry weight of the aerosol-generating substrate, more preferably at least 6 wt% aerosol-forming agent based on dry weight of the aerosol-generating substrate, and at least 8 wt% aerosol-forming agent based on dry weight of the aerosol-generating substrate.

Preferably, the aerosol-generating substrate comprises less than 90 wt% aerosol-forming agent based on dry weight of the aerosol-generating substrate, more preferably less than 80 wt% aerosol-forming agent based on dry weight of the aerosol-generating substrate, more preferably less than 70 wt% aerosol-forming agent based on dry weight of the aerosol-generating substrate, more preferably less than 60 wt% aerosol-forming agent based on dry weight of the aerosol-generating substrate, more preferably less than 50 wt% aerosol-forming agent based on dry weight of the aerosol-generating substrate, more preferably less than 40 wt% aerosol-forming agent based on dry weight of the aerosol-generating substrate.

More preferably, the aerosol-generating substrate comprises less than 30 wt% aerosol-forming agent based on dry weight of the aerosol-generating substrate, more preferably less than 25 wt% aerosol-forming agent based on dry weight of the aerosol-generating substrate, more preferably less than 20 wt% aerosol-forming agent based on dry weight of the aerosol-generating substrate.

For example, the aerosol-generating substrate may comprise between 5 and 30% by weight of aerosol-forming agent based on the dry weight of the aerosol-generating substrate, more preferably between 6 and 25% by weight of aerosol-forming agent based on the dry weight of the aerosol-generating substrate, more preferably between 10 and 20% by weight of aerosol-forming agent based on the dry weight of the aerosol-generating substrate.

For example, preferably the aerosol-generating substrate may comprise between 5 and 30% by weight of glycerol based on the dry weight of the aerosol-generating substrate, more preferably between 6 and 25% by weight of glycerol based on the dry weight of the aerosol-generating substrate, more preferably between 10 and 20% by weight of glycerol based on the dry weight of the aerosol-generating substrate. In certain preferred embodiments of the invention, the aerosol-generating substrate comprises shredded tobacco material. For example, as described in more detail below, the shredded tobacco material may be in the form of shredded filler. Alternatively, the shredded tobacco material may be in the form of shredded sheets of homogenized tobacco material. Suitable homogenized tobacco materials for use in the present invention are described below.

In the context of the present specification, the term "cut filler" is used to describe a blend of cut plant material (e.g. tobacco plant material), including in particular one or more of lamina, processed stems and ribs, homogenized plant material.

Cut filler may also include other post-cut filler tobacco or charges.

Preferably, the cut filler comprises at least 25% plant leaves, more preferably at least 50% plant leaves, still more preferably at least 75% plant leaves, and most preferably at least 90% plant leaves. Preferably, the plant material is one of tobacco, peppermint, tea and clove. Most preferably, the plant material is tobacco. However, as will be discussed in more detail below, the present invention is equally applicable to other plant materials capable of releasing substances that may subsequently form aerosols upon application of heat.

Preferably, the cut filler comprises tobacco plant material comprising a lamina of one or more of cured tobacco, sun cured tobacco, cured tobacco and filler tobacco. With reference to the present invention, the term "tobacco" describes any plant member of the genus nicotiana. Flue-cured tobacco is tobacco with generally large, pale leaves. Throughout the specification, the term "cured tobacco" is used for cured tobacco. Examples of flue-cured tobacco are Chinese flue-cured tobacco, brazil flue-cured tobacco, american flue-cured tobacco, such as Virginia tobacco, india flue-cured tobacco, tank Municha flue-cured tobacco or other African flue-cured tobacco. Flue-cured tobacco is characterized by a high sugar to nitrogen ratio. From a sensory perspective, flue-cured tobacco is a type of tobacco that is accompanied by a spicy and refreshing sensation after curing. Within the scope of the present invention, flue-cured tobacco is tobacco having a reducing sugar content of between about 2.5% and about 20% by dry weight of tobacco and a total ammonia content of less than about 0.12% by dry weight of tobacco. Reducing sugars include, for example, glucose or fructose. Total ammonia includes, for example, ammonia and ammonia salts.

Sun-cured tobacco is tobacco with generally large dark leaves. Throughout the specification, the term "sun-cured" is used for cured tobacco. In addition, sun-cured tobacco can be fermented. Tobacco that is primarily used in chewing, snuff, cigar and pipe blends is also included in this category. Typically, these sun-cured cigarettes are subjected to a drying process and may be fermented. From a sensory perspective, sun-cured tobacco is a type of tobacco that is accompanied by a dark cigar-like sensation of smoky flavor after baking. Sun-cured cigarettes are characterized by a low sugar to nitrogen ratio. Examples of sun cigarettes are malassezia bura or other african bura, dark-baked Brazil bubble (Brazil Galpao), sun-dried or sun-dried indonesia spider blue (Indonesian Kasturi). According to the invention, sun-cured tobacco is tobacco having a reducing sugar content of less than about 5% by dry weight of tobacco and a total ammonia content of up to about 0.5% by dry weight of tobacco.

Flavoured tobacco is tobacco that often has small pale leaves. Throughout this specification, the term "flavor tobacco" is used for other tobacco having a high aromatic content (e.g., essential oils). From a sensory perspective, flavored tobacco is a type of tobacco that is accompanied by a spicy and aromatic sensation following baking. Examples of flavoured tobacco are greek oriental, eastern tulip, hemi-eastern tobacco, and roasted us burley, such as perlick (Perique), yellow flower smoke (Rustica), us burley or Mo Lilan (Meriland). Filler tobacco is not a specific tobacco type, but it contains tobacco types that are primarily used to supplement other tobacco types used in the blend and do not carry specific characteristic aromas into the final product. Examples of filler tobacco are stems, midribs or stalks of other tobacco types. A specific example may be a baked stem of the lower stem of brazil flue-cured tobacco.

Cut filler suitable for use with the present invention may be substantially similar to cut filler used in conventional smoking articles. The cut filler preferably has a cut width of between 0.3 and 2.0 millimeters, more preferably a cut width of between 0.5 and 1.2 millimeters, and most preferably a cut width of between 0.6 and 0.9 millimeters. The filament width may play a role in the heat distribution inside the strip of aerosol-generating substrate. Also, the filament width can play a role in the suction resistance of the article. Furthermore, the filament width may affect the overall density of the aerosol-generating substrate as a whole.

The strand length of the cut filler is somewhat a random value, as the length of the strand will depend on the overall size of the object from which the strand is cut. However, by adjusting the material prior to cutting, for example by controlling the moisture content and overall fineness of the material, longer strands can be cut. Preferably, the strands have a length of between about 10 mm and about 40 mm before finishing the strands to form the strips of aerosol-generating substrate. Obviously, if the strands are arranged in a longitudinal extension in a strip of aerosol-generating substrate, wherein the longitudinal extension of the section is below 40 mm, the strip of final aerosol-generating substrate may comprise strands that on average are shorter than the length of the initial strands. Preferably, the strand length of the cut filler is such that between about 20% and 60% of the strands extend along the full length of the strip of aerosol-generating substrate. This prevents the strands from being easily removed from the strip of aerosol-generating substrate.

In a preferred embodiment, the weight of the cut filler is between 80 mg and 400 mg, preferably between 150 mg and 250 mg, more preferably between 170 mg and 220 mg. This amount of cut filler generally allows for sufficient material for aerosol formation. In addition, in view of the above constraints on diameter and size, where the aerosol-generating substrate comprises plant material, this allows for an equilibrium density between the energy absorption, resistance to draw and fluid passage within the strip of aerosol-generating substrate.

Preferably, the cut filler is impregnated with an aerosol former. The infusion of the cut filler may be accomplished by spraying or by other suitable application methods. The aerosol former may be applied to the blend during the preparation of the cut filler. For example, the aerosol former may be applied to a blend in a direct regulated feed cartridge (direct conditioning CASING CYLINDER, DCCC). The aerosol former may be applied to the cut filler using conventional machinery. The aerosol former may be any suitable known compound or mixture of compounds that aids in forming a dense and stable aerosol in use. The aerosol-former may facilitate substantial resistance of the aerosol to thermal degradation at temperatures applied during typical use of the aerosol-generating article. Suitable aerosol formers are, for example: polyhydric alcohols such as triethylene glycol, 1, 3-butanediol, propylene glycol and glycerol; esters of polyols, such as glycerol mono-, di-or triacetate; aliphatic esters of monocarboxylic, dicarboxylic or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate; and combinations thereof.

Preferably, the amount of aerosol former is at least 5 wt% on a dry weight basis, preferably between 5 and 30 wt% on a dry weight basis of the cut filler, more preferably between 6 and 20 wt% on a dry weight basis of the cut filler, for example between 8 and 15 wt% on a dry weight basis of the cut filler. When the aerosol former is added to the cut filler in the above amounts, the cut filler may become relatively viscous. This advantageously helps to retain the cut filler in a predetermined position within the article because the particles of cut filler exhibit a tendency to adhere to the surrounding cut filler particles as well as to surrounding surfaces (e.g., the inner surface of the wrapper defining the cut filler).

For some embodiments, the amount of aerosol former has a target value of about 13 wt% based on the dry weight of the cut filler. Whether the cut filler comprises plant leaves or homogenized plant material, the most effective amount of aerosol former will also depend on the cut filler. For example, the type of cut filler will determine, among other factors, to what extent the aerosol former can facilitate release of material from the cut filler.

For these reasons, as described above, a rod of aerosol-generating substrate comprising cut filler is capable of effectively generating a sufficient amount of aerosol at relatively low temperatures. Temperatures in the heating chamber between 150 degrees celsius and 200 degrees celsius may be sufficient for one such cut filler to generate a sufficient amount of aerosol, while in aerosol-generating devices employing tobacco cast vanes, temperatures of about 250 degrees celsius are typically employed.

Another advantage associated with operating at lower temperatures is the reduced need to cool the aerosol. Since low temperatures are generally used, a simpler cooling function is sufficient. This in turn allows for the use of a simpler and less complex structure of the aerosol-generating article.

In other preferred embodiments, the aerosol-generating substrate comprises homogenized plant material, preferably homogenized tobacco material.

As used herein, the term "homogenized plant material" includes any plant material formed from the agglomeration of plant particles. For example, a sheet or web of homogenized tobacco material for use in an aerosol-generating substrate of the invention may be formed by agglomerating particles of tobacco material obtained by comminuting, grinding or milling plant material and optionally one or more of tobacco lamina and tobacco leaf stems. The homogenized plant material may be produced by casting, extrusion, papermaking processes, or any other suitable process known in the art.

The homogenized plant material may be provided in any suitable form.

In some embodiments, the homogenized plant material may be in the form of one or more sheets. As used herein with reference to the present invention, the term "sheet" describes a layered element having a width and length substantially greater than its thickness.

The homogenized plant material may be in the form of a plurality of pellets or granules.

The homogenized plant material may be in the form of a plurality of strands, ribbons or pieces. As used herein, the term "strand" describes an elongated element material that has a length that is substantially greater than its width and thickness. The term "strand" shall be considered to include ribbons, chips and any other homogenized plant material having a similar form. Strands of homogenized plant material may be formed from sheets of homogenized plant material, such as by cutting or chopping, or by other methods, such as by extrusion methods.

In some embodiments, the strands may form in situ ‭ within the aerosol-generating substrate ‭ ‬ due to splitting or splitting of the sheet of homogenized plant material during formation of the aerosol-generating substrate, e.g., due to crimping. The homogenized plant material strands within the aerosol-generating substrate may be separated from each other. Alternatively, each strand of homogenized plant material within the aerosol generating substrate may be connected to adjacent one or more strands at least partially along the length of the strand. For example, adjacent strands may be connected by one or more fibers. This may occur, for example, in the case of strands formed due to splitting of sheets of homogenized plant material during production of the aerosol-generating substrate, as described above.

As described above, when the homogenized plant material is in the form of one or more sheets, the sheets may be produced by a casting process. Alternatively, the sheet of homogenized plant material may be produced by a papermaking process.

The one or more sheets as described herein may each individually have a thickness of between 100 microns and 600 microns, preferably between 150 microns and 300 microns, and most preferably between 200 microns and 250 microns. The individual thickness refers to the thickness of the individual sheets, while the combined thickness refers to the total thickness of all sheets constituting the aerosol-generating substrate. For example, if the aerosol-generating substrate is formed from two separate sheets, the combined thickness is the sum of the thicknesses of the two separate sheets or the measured thickness of the two sheets in case the two sheets are stacked in the aerosol-generating substrate.

One or more sheets as described herein may each individually have a grammage of between 100 grams per square meter and 600 grams per square meter.

The one or more sheets as described herein may each individually have a density of 0.3 g/cc to 1.3 g/cc, and preferably 0.7 g/cc to 1.0 g/cc.

In embodiments of the invention in which the aerosol-generating substrate comprises one or more sheets of homogenized plant material, the sheets are preferably in the form of one or more aggregated sheets. As used herein, the term "gathered" means that the homogenized plant material sheet is rolled, folded or otherwise compressed or contracted substantially transverse to the cylindrical axis of the rod or bar.

One or more sheets of homogenized plant material may be gathered transversely with respect to its longitudinal axis and defined with a wrapper to form a continuous strip or rod.

One or more sheets of homogenized plant material may advantageously be curled or similarly treated. As used herein, the term "curled" means that the sheet has a plurality of substantially parallel ridges or corrugations. One or more sheets of homogenized plant material may be embossed, gravure, perforated, or otherwise deformed to provide texture on one or both sides of the sheet.

Preferably, one or more sheets of homogenized plant material may be curled such that they have a plurality of ridges or corrugations substantially parallel to the cylindrical axis of the rod. This treatment advantageously promotes aggregation of the curled sheet of homogenised plant material to form a rod. Preferably, one or more sheets of homogenized plant material may be gathered. It will be appreciated that the curled sheet of homogenised plant material may alternatively or additionally have a plurality of substantially parallel ridges or corrugations arranged at an acute or obtuse angle to the cylindrical axis of the rod. The sheet may be curled to such an extent that the integrity of the sheet is compromised at the plurality of parallel ridges or corrugations, causing the material to separate and resulting in the formation of fragments, strands or ribbons of homogenized plant material.

One or more sheets of homogenized plant material may be cut into strands as described above. In such embodiments, the aerosol-generating substrate comprises a plurality of homogenized plant material strands. Strands may be used to form the rod. Typically, the strands have a width of about 5 millimeters, or about 4 millimeters, or about 3 millimeters, or about 2 millimeters or less. The strands may have a length greater than about 5 millimeters, between about 5 millimeters and about 15 millimeters, between about 8 millimeters and about 12 millimeters, or about 12 millimeters. Preferably, the strands have substantially the same length as each other.

The homogenized plant material may comprise up to 95 weight percent plant particles on a dry weight basis. Preferably, the homogenized plant material comprises up to 90 wt.% plant particles, more preferably up to 80 wt.% plant particles, more preferably up to 70 wt.% plant particles, more preferably up to 60 wt.% plant particles, more preferably up to 50 wt.% plant particles on a dry weight basis.

For example, the homogenized plant material may comprise between 2.5 wt.% and 95 wt.% plant particles, or between 5 wt.% and 90 wt.% plant particles, or between 10 wt.% and 80 wt.% plant particles, or between 15 wt.% and 70 wt.% plant particles, or between 20 wt.% and 60 wt.% plant particles, or between 30 wt.% and 50 wt.% plant particles, on a dry weight basis.

In certain embodiments of the invention, the homogenized plant material is homogenized tobacco material comprising tobacco particles. The sheet of homogenized tobacco material for such embodiments of the invention may have a tobacco content of at least about 40 percent by weight on a dry basis, more preferably at least about 50 percent by weight on a dry basis, more preferably at least about 70 percent by weight on a dry basis, and most preferably at least about 90 percent by weight on a dry basis.

With reference to the present invention, the term "tobacco particles" describes particles of any plant member of the genus nicotiana. The term "tobacco particles" includes ground or crushed tobacco lamina, ground or crushed tobacco stem, tobacco dust, tobacco fines and other particulate tobacco by-products formed during the handling, operation and transportation of tobacco. In a preferred embodiment, the tobacco particles are substantially entirely derived from tobacco lamina. In contrast, the isolated nicotine and nicotine salts are tobacco-derived compounds, but are not considered tobacco particles for the purposes of the present invention and are not included in the percentage of particulate plant material.

The homogenized plant material may also comprise one or more aerosol formers. Upon volatilization, the aerosol-forming agent can deliver other volatilized compounds such as nicotine and flavoring agents in the aerosol that are released from the aerosol-generating substrate upon heating. Suitable aerosol formers included in homogenized plant material are known in the art and include, but are not limited to: polyols such as triethylene glycol, propylene glycol, 1, 3-butanediol and glycerol; esters of polyols, such as glycerol mono-, di-, or triacetate; and aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate.

The homogenized plant material may have an aerosol former content of between 5 and 30 wt% on a dry weight basis, for example between 10 and 25 wt% on a dry weight basis or between 15 and 20 wt% on a dry weight basis. The aerosol former may act as a humectant in the homogenized plant material.

In certain embodiments of the invention, the aerosol-generating article further comprises a susceptor element within the strip of aerosol-generating substrate. For example, the elongate susceptor element may be arranged substantially longitudinally within the strip of aerosol-generating substrate and in thermal contact with the aerosol-generating substrate.

As used herein with reference to the present invention, the term "susceptor element" refers to a material capable of converting electromagnetic energy into heat. When located within the fluctuating electromagnetic field, eddy currents induced in the susceptor element lead to heating of the susceptor element. Since the susceptor element is positioned in thermal contact with the aerosol-generating substrate, the aerosol-generating substrate is heated by the susceptor element.

When used in reference to a susceptor element, the term "elongated" means that the length dimension of the susceptor element is greater than its width dimension or its thickness dimension, for example greater than twice its width dimension or its thickness dimension.

The susceptor element is arranged substantially longitudinally within the strip. This means that the length dimension of the elongated susceptor element is arranged substantially parallel to the longitudinal direction of the strip, for example within plus or minus 10 degrees of parallel to the longitudinal direction of the strip. In a preferred embodiment, the elongate susceptor element may be positioned in a radially central position within the strip and extend along the longitudinal axis of the strip.

Preferably, the susceptor element extends all the way to the downstream end of the strip of aerosol-generating substrate. In some embodiments, the susceptor element may extend all the way to the upstream end of the strip of aerosol-generating substrate. In a particularly preferred embodiment, the susceptor element has substantially the same length as the strip of aerosol-generating substrate and extends from an upstream end of the strip to a downstream end of the strip.

The susceptor element is preferably in the form of a pin, a bar, a strip or a vane.

The susceptor element preferably has a length of 10 to 40 mm, for example 15 to 35 mm or 17 to 30 mm.

The susceptor element preferably has a length of 5 to 15mm, for example 6 to 12 mm or 8 to 10 mm.

The susceptor element preferably has a width of 1 to 5mm.

The susceptor element typically has a thickness of 0.01 to 2 mm, for example 0.5 to 2 mm. In some embodiments, the susceptor element preferably has a thickness of 10 to 500 microns, more preferably 10 to 100 microns.

If the susceptor element has a constant cross-section, for example a circular cross-section, it has a preferred width or diameter of 1 to 5 mm.

If the susceptor element has the form of a strip or a blade, the strip or blade preferably has a rectangular shape with a width of preferably 2 to 8 mm, more preferably 3 to 5 mm. For example, the susceptor element in the form of a strip or a blade may have a width of 4 mm.

If the susceptor element has the form of a strip or a vane, the strip or vane preferably has a rectangular shape and a thickness of 0.03 to 0.15 mm, more preferably 0.05 to 0.09 mm. For example, the susceptor element in the form of a strip or a vane may have a thickness of 0.07 mm.

In a preferred embodiment, the elongated susceptor element is in the form of a strip or vane, preferably having a rectangular shape, and having a thickness of 55 to 65 micrometers.

More preferably, the elongate susceptor element has a thickness of 57 to 63 microns. Even more preferably, the elongate susceptor element has a thickness of from 58 micrometers to 62 micrometers. In a particularly preferred embodiment, the elongate susceptor element has a thickness of 60 micrometers.

Preferably, the elongate susceptor element has a length which is the same as or shorter than the length of the aerosol-generating substrate. Preferably, the elongate susceptor element has the same length as the aerosol-generating substrate.

The susceptor element may be formed of any material capable of being inductively heated to a temperature sufficient to generate an aerosol from the aerosol-generating substrate. Preferably the susceptor element comprises metal or carbon.

Preferred susceptor elements may comprise or consist of ferromagnetic materials, such as ferromagnetic alloys, ferritic iron, or ferromagnetic steel or stainless steel. Suitable susceptor elements may be or include aluminum. The preferred susceptor element may be formed from a 400 series stainless steel, such as grade 410 or grade 420 or grade 430 stainless steel. When positioned within an electromagnetic field having similar frequency and field strength values, different materials will dissipate different amounts of energy.

Thus, parameters of the susceptor element such as material type, length, width and thickness may all be modified to achieve a desired power dissipation within a known electromagnetic field. The preferred susceptor element may be heated to a temperature in excess of 250 degrees celsius.

Suitable susceptor elements may include a nonmetallic core having a metal layer disposed on the nonmetallic core, such as metal tracks formed on a surface of a ceramic core. The susceptor element may have an outer protective layer, for example a ceramic protective layer or a glass protective layer, which encapsulates the susceptor element. The susceptor element may comprise a protective coating formed of glass, ceramic or an inert metal, which protective coating is formed on the core of susceptor element material.

The susceptor element is arranged in thermal contact with the aerosol-generating substrate. Thus, when the susceptor element heats up, the aerosol-generating substrate heats up and forms an aerosol. Preferably, the susceptor element is arranged in direct physical contact with the aerosol-generating substrate, e.g. within the aerosol-generating substrate.

As mentioned above, the strips of aerosol-generating substrate may be defined by the wrapper. The wrapper of the strip defining the aerosol-generating substrate may be a paper wrapper or a non-paper wrapper. Suitable paper packages for use in certain embodiments of the present invention are known in the art and include, but are not limited to: a cigarette paper; and a filter segment wrapper. Suitable non-paper wrappers for use in particular embodiments of the invention are known in the art and include, but are not limited to, sheets of homogenized tobacco material.

The paper wrapper may have a grammage of at least 15gsm (grams per square meter), preferably at least 20 gsm. The paper wrapper may have a grammage of less than or equal to 35gsm, preferably less than or equal to 30 gsm. The paper wrapper may have a grammage of 15gsm to 35gsm, preferably 20gsm to 30 gsm. In a preferred embodiment, the paper wrapper may have a grammage of 25 gsm. The paper wrapper may have a thickness of at least 25 microns, preferably at least 30 microns, more preferably at least 35 microns. The paper wrapper may have a thickness of less than or equal to 55 microns, preferably less than or equal to 50 microns, more preferably less than or equal to 45 microns. The paper wrapper may have a thickness of 25 microns to 55 microns, preferably 30 microns to 50 microns, more preferably 35 microns to 45 microns. In a preferred embodiment, the paper wrapper may have a thickness of 40 microns.

In certain preferred embodiments, the wrapper may be formed from a laminate comprising a plurality of layers. Preferably, the wrapper is formed from an aluminium co-laminate sheet. The use of a co-laminated sheet comprising aluminium advantageously prevents combustion of the aerosol-generating substrate in case the aerosol-generating substrate should be ignited instead of heated in the intended manner.

The paper layer of the co-laminated sheet may have a grammage of at least 35gsm, preferably at least 40 gsm. The paper layer of the co-laminated sheet may have a grammage of less than or equal to 55gsm, preferably less than or equal to 50 gsm. The paper layer of the co-laminated sheet may have a grammage of 35gsm to 55gsm, preferably 40gsm to 50 gsm. In a preferred embodiment, the paper layer of the co-laminated sheet may have a grammage of 45 gsm.

The paper layer of the co-laminated sheet may have a thickness of at least 50 microns, preferably at least 55 microns, more preferably at least 60 microns. The paper layers of the co-laminated sheet may have a thickness of less than or equal to 80 microns, preferably less than or equal to 75 microns, more preferably less than or equal to 70 microns.

The paper layer of the co-laminated sheet may have a thickness of 50 to 80 microns, preferably 55 to 75 microns, more preferably 60 to 70 microns. In a preferred embodiment, the paper layer of the co-laminated sheet may have a thickness of 65 microns.

The metal layer of the co-laminate sheet may have a grammage of at least 12gsm, preferably at least 15 gsm. The metal layer of the co-laminate sheet may have a grammage of less than or equal to 25gsm, preferably less than or equal to 20 gsm. The metal layer of the co-laminated sheet may have a grammage of 12gsm to 25gsm, preferably 15gsm to 20 gsm. In a preferred embodiment, the metal layer of the co-laminate sheet may have a grammage of 17 gsm.

The metal layer of the co-laminate sheet may have a thickness of at least 2 microns, preferably at least 3 microns, more preferably at least 5 microns. The metal layer of the co-laminate sheet may have a thickness of less than or equal to 15 microns, preferably less than or equal to 12 microns, more preferably less than or equal to 10 microns.

The metal layer of the co-laminate sheet may have a thickness of 2 to 15 microns, preferably 3 to 12 microns, more preferably 5 to 10 microns. In a preferred embodiment, the metal layer of the co-laminate sheet may have a thickness of 6 microns.

The wrapper of the strip defining the aerosol-generating substrate may be a paper wrapper comprising PVOH (polyvinyl alcohol) or silicone (or polysiloxane). The addition of PVOH (polyvinyl alcohol) or silicone (or polysiloxane) can improve the grease barrier properties of the package.

PVOH or silicone (or polysiloxane) may be applied as a surface coating to the paper layer, such as being provided on the outer surface of a wrapper paper layer defining a strip of aerosol generating substrate. PVOH or silicone (or polysiloxane) may be disposed on the outer surface of the paper layer of the package and form a layer thereon. PVOH or silicone (or polysiloxane) may be provided on the inner surface of the paper layer of the package. PVOH or silicone (or polysiloxane) may be disposed on the inner surface of the paper layer of the aerosol-generating article and form a layer thereon. PVOH or silicone (or polysiloxane) may be provided on the inner and outer surfaces of the paper layer of the package. PVOH or silicone (or polysiloxane) may be disposed on the inner and outer surfaces of the paper layer of the package and form a layer thereon.

Paper packages comprising PVOH or silicone (or polysiloxanes) can have a grammage of at least 20gsm, preferably at least 25gsm, more preferably at least 30 gsm. Paper packages comprising PVOH or silicone (or polysiloxanes) can have a grammage of less than or equal to 50gsm, preferably less than or equal to 45gsm, more preferably less than or equal to 40 gsm. Paper packages comprising PVOH or silicone (or polysiloxanes) can have a grammage of 20gsm to 50gsm, preferably 25gsm to 45gsm, more preferably 30gsm to 40 gsm. In particularly preferred embodiments, paper packages comprising PVOH or silicone (or polysiloxane) may have a grammage of 35 gsm.

The paper wrapper comprising PVOH or silicone (or polysiloxane) can have a thickness of at least 25 microns, preferably at least 30 microns, more preferably at least 35 microns. Paper packages comprising PVOH or silicone (or polysiloxane) can have a thickness of less than or equal to 50 microns, preferably less than or equal to 45 microns, more preferably less than or equal to 40 microns. The paper wrapper comprising PVOH or silicone (or polysiloxane) can have a thickness of 25 microns to 50 microns, preferably 30 microns to 45 microns, more preferably 35 microns to 40 microns. In a particularly preferred embodiment, the paper wrapper comprising PVOH or silicone (or polysiloxane) may have a thickness of 37 microns.

The wrapper defining the strip of aerosol-generating substrate may comprise a flame retardant composition comprising one or more flame retardant compounds. The term "flame retardant compound" is used herein to describe a compound that provides a carrier substrate (e.g., a paper or plastic compound) with varying degrees of flammability protection when added to or otherwise incorporated into the carrier substrate. In practice, the flame retardant compound may be activated by the presence of an ignition source and is adapted to prevent or slow down further development of ignition by a variety of different physical and chemical mechanisms.

The flame retardant composition may also typically include one or more non-flame retardant compounds, i.e., one or more compounds (e.g., solvents, excipients, fillers), which do not positively contribute to providing flammability protection to the carrier substrate, but are used to facilitate application of the one or more flame retardant compounds onto or into the package or both onto and into the package. Some non-flame retardant compounds of the flame retardant composition, such as solvents, are volatile and may evaporate from the package upon drying after the flame retardant composition is applied to or in the package base material or both. Thus, although such non-flame retardant compounds form part of the formulation of the flame retardant composition, they may no longer be present or they may only be detectable in trace amounts in the packaging of the aerosol-generating article.

Many suitable flame retardant compounds are known to the skilled person. In particular, several flame retardant compounds and formulations suitable for treating cellulosic materials are known and have been disclosed and can be used in the manufacture of packages for aerosol-generating articles according to the present invention.

For example, the flame retardant composition may include a polymer and a mixed salt based on at least one monocarboxylic acid, dicarboxylic acid, and/or tricarboxylic acid, at least one polyphosphoric acid, pyrophosphoric acid, and/or phosphoric acid, and an alkali or alkaline earth metal hydroxide or salt, wherein the at least one monocarboxylic acid, dicarboxylic acid, and/or tricarboxylic acid forms a carboxylate salt with the hydroxide or salt, and the at least one polyphosphoric acid, pyrophosphoric acid, and/or phosphoric acid forms a phosphate salt with the hydroxide or salt. Preferably, the flame retardant composition may further comprise an alkali metal or alkaline earth metal carbonate. Alternatively, the flame retardant composition may comprise cellulose modified with at least one C ‭ ₁₀ or higher fatty acid, tall Oil Fatty Acid (TOFA), phosphorylated linseed oil, phosphorylated downstream corn oil. Preferably, the at least one C ₁₀ or higher fatty acid is selected from capric acid, myristic acid, palmitic acid, and combinations thereof.

In packages comprising a flame retardant composition suitable for use in aerosol-generating articles according to the invention, the flame retardant composition may be provided in a treated portion of the package. This means that the flame retardant composition has been applied to or in the corresponding portion of the packaging base material of the package, or both. Thus, in the treatment section, the wrapper has an overall dry basis weight that is greater than the dry basis weight of the wrapper base material. The treatment portion of the wrapper may extend over at least 10% of the outer surface area of the strip of aerosol-generating substrate defined by the wrapper, preferably over at least 20% of the outer surface area of the strip of aerosol-generating substrate defined by the wrapper, more preferably over at least 40% of the outer surface area of the strip of aerosol-generating substrate, even more preferably over at least 60% of the outer surface area of the strip of aerosol-generating substrate. Most preferably, the treated portion of the wrapper extends over at least 80% of the outer surface area of the strip of aerosol-generating substrate. In a particularly preferred embodiment, the treated portion of the wrapper extends over at least 90% or even 95% of the outer surface area of the strip of aerosol-generating substrate. Most preferably, the treated portion of the wrapper extends substantially over the entire outer surface area of the strip of aerosol-generating substrate.

Packages comprising the flame retardant composition may have a grammage of at least 20gsm, preferably at least 25gsm, more preferably at least 30 gsm. Packages comprising the flame retardant composition may have a grammage of less than or equal to 45gsm, preferably less than or equal to 40gsm, more preferably less than or equal to 35 gsm. Packages comprising the flame retardant composition may have a grammage of 20gsm to 45gsm, preferably 25gsm to 40gsm, more preferably 30gsm to 35 gsm. In some preferred embodiments, the wrapper comprising the flame retardant composition may have a grammage of 33 gsm.

Packages comprising the flame retardant composition may have a thickness of at least 25 microns, preferably at least 30 microns, even more preferably 35 microns. Packages comprising the flame retardant composition may have a thickness of less than or equal to 50 microns, preferably less than or equal to 45 microns, even more preferably less than or equal to 40 microns. In some embodiments, the package comprising the flame retardant composition may have a thickness of 37 microns.

The aerosol-generating article according to the present disclosure may further comprise an upstream section located upstream of the strip of aerosol-generating substrate. The upstream section is preferably located immediately upstream of the strip of aerosol-generating substrate. The upstream section preferably extends between the upstream end of the aerosol-generating article and the strip of aerosol-generating substrate. The upstream section may comprise one or more upstream elements located upstream of the strip of aerosol-generating substrate. Such one or more upstream elements are described within this disclosure.

The aerosol-generating article of the invention preferably comprises an upstream element located upstream and in the vicinity of the aerosol-generating substrate. The upstream element advantageously prevents direct physical contact with the upstream end of the aerosol-generating substrate. For example, in case the aerosol-generating substrate comprises a susceptor element, the upstream element may prevent direct physical contact with the upstream end of the susceptor element. This helps to prevent the susceptor element from being dislodged or deformed during handling or transporting the aerosol-generating article. This in turn helps to fix the form and position of the susceptor element. Furthermore, the presence of the upstream element helps to prevent any loss of the substrate, which may be advantageous, for example, if the substrate contains particulate plant material.

Where the aerosol-generating substrate comprises shredded tobacco (e.g. tobacco cut filler), the upstream section or element thereof may additionally help prevent loss of loose tobacco particles from the upstream end of the article. This may be particularly important, for example, when the shredded tobacco has a relatively low density.

The upstream section or upstream element thereof may additionally provide a degree of protection for the aerosol-generating substrate during storage, as it covers at least to some extent the upstream end of the aerosol-generating substrate that might otherwise be exposed.

For aerosol-generating articles intended to be inserted into a cavity in an aerosol-generating device such that the aerosol-generating substrate is heatable inside and outside the cavity, the upstream section or upstream element thereof may advantageously facilitate insertion of the upstream end of the article into the cavity. The inclusion of the upstream element may additionally protect the end of the strip of aerosol-generating substrate during insertion of the article into the cavity, so that the risk of damage to the substrate is minimised.

The upstream section or upstream element thereof may also provide an improved appearance to the upstream end of the aerosol-generating article. Furthermore, if desired, the upstream section or upstream element thereof may be used to provide information about the aerosol-generating article, such as information about the brand, flavor, content, or details of the aerosol-generating device with which the article is intended to be used.

The upstream element may be a porous rod element. Preferably, the upstream element has a porosity of at least 50% in the longitudinal direction of the aerosol-generating article. More preferably, the upstream element has a porosity in the longitudinal direction of between 50% and 90%. The porosity of the upstream element in the longitudinal direction is defined by the ratio of the cross-sectional area of the material forming the upstream element to the internal cross-sectional area of the aerosol-generating article at the location of the upstream element.

The upstream element may be made of a porous material or may include a plurality of openings. This may be achieved, for example, by laser perforation. Preferably, the plurality of openings are evenly distributed over the cross section of the upstream element.

The porosity or permeability of the upstream element may advantageously be designed to provide a particular overall Resistance To Draw (RTD) to the aerosol-generating article without substantially affecting the filtration provided by the other portions of the article.

The upstream element may be formed of an air impermeable material. In such embodiments, the aerosol-generating article may be configured such that air flows into the strip of aerosol-generating substrate through a suitable ventilation means provided in the wrapper.

In certain preferred embodiments of the present invention, it may be desirable to minimize RTDs of upstream elements. For example, as described herein, this may be the case for articles intended to be inserted into a cavity of an aerosol-generating device such that the aerosol-generating substrate is externally heated. For such articles, it is desirable to provide the article with as low an RTD as possible so that most of the RTD experience of the consumer is provided by the aerosol-generating device rather than the article.

The RTD of the upstream element is preferably less than 30 mm H ₂ O. More preferably, the RTD of the upstream element is less than 20mm H ₂ O. Even more preferably, the RTD of the upstream element is less than or equal to 10 mm H ₂ O. Even more preferably, the RTD of the upstream element is less than or equal to 5mm H ₂ O. Even more preferably, the RTD of the upstream element is less than or equal to 2mm H ₂ O.

The RTD of the upstream element may be at least 0.1 mm H ₂ O, or at least 0.25 mm H ₂ O, or at least 0.5 mm H ₂ O.

In some embodiments, the RTD of the upstream element is from 0.1 mm H ₂ O to 30 mm H ₂ O, preferably from 0.25 mm H ₂ O to 30 mm H ₂ O, Preferably 0.5 mm H ₂ O to 30 mm H ₂ O. In other embodiments, the RTD of the upstream element is from 0.1 mm H ₂ O to 20 mm H ₂ O, preferably from 0.25 mm H ₂ O to 20 mm H ₂ O, Preferably 0.5 mm H ₂ O to 20 mm H ₂ O. In further embodiments, the RTD of the upstream element is from 0.1 mm H ₂ O to 10mm H ₂ O, preferably from 0.25 mm H ₂ O to 10mm H ₂ O, more preferably from 0.5 mm H ₂ O to 10 mm H ₂ O. In further embodiments, the RTD of the upstream element is from 0.1mm H ₂ O to 5mm H ₂ O, preferably from 0.25 mm H ₂ O to 5mm H ₂ O, More preferably from 0.5 mm H ₂ O to 5mm H ₂ O. in further embodiments, the RTD of the upstream element is from 0.1mm H ₂ O to 2 mm H ₂ O, preferably from 0.25 mm H ₂ O to 2 mm H ₂ O, More preferably from 0.5 mm H ₂ O to 2 mm H ₂ O.

Preferably, the RTD of the upstream element is less than 2mm H ₂ O/mm in length, more preferably less than 1.5 mm H ₂ O/mm in length, more preferably less than 1 mm H ₂ O/mm in length, more preferably less than 0.5 mm H ₂ O/mm in length, more preferably less than 0.3 mm H ₂ O/mm in length, more preferably less than 0.2mm H ₂ O/mm in length.

Preferably, the combined RTD of the upstream section or upstream element thereof and the strip of aerosol-generating substrate is less than 15 mm H ₂ O, more preferably less than 12 mm H ₂ O, more preferably less than 10 mm H ₂ O.

In certain preferred embodiments, the upstream element is formed from a solid cylindrical rod element having a packed cross section. Such rod elements may be referred to as "normal" elements. As mentioned above, the solid rod element may be porous but not have a tubular form and thus do not provide a longitudinal flow channel. The solid rod elements preferably have a substantially uniform cross-section.

In other preferred embodiments, the upstream element is formed by a hollow tubular section defining a longitudinal cavity providing an unrestricted flow channel. In such embodiments, the upstream element may provide protection to the aerosol-generating substrate while having minimal impact on the overall Resistance To Draw (RTD) and filtration characteristics of the article, as described above.

Preferably, the diameter of the longitudinal cavity of the hollow tubular section forming the upstream element is at least 3 mm, more preferably at least 3.5 mm, more preferably at least 4 mm, and more preferably at least 4.5 mm. Preferably, the diameter of the longitudinal cavity is maximized in order to minimize the RTD of the upstream section or upstream element thereof.

Preferably, the hollow tubular section has a wall thickness of less than 2 mm, more preferably less than 1.5 mm, and more preferably less than 1 mm.

The upstream element of the upstream section may be made of any material suitable for use in aerosol-generating articles. The upstream element may for example be made of the same material as used for one of the other components of the aerosol-generating article, such as the downstream filter segment or the hollow tubular cooling element. Suitable materials for forming the upstream element include filter materials, ceramics, polymeric materials, cellulose acetate, cardboard, zeolites, or aerosol-generating substrates. The upstream element may comprise a rod of cellulose acetate. The upstream element may comprise a hollow acetate tube or a cardboard tube.

Preferably, the upstream element is formed of a heat resistant material. For example, it is preferred that the upstream element is formed of a material that resists temperatures up to 350 degrees celsius. This ensures that the upstream element is not adversely affected by the heating means used to heat the aerosol-generating substrate.

Preferably, the upstream section or upstream element thereof has an outer diameter substantially equal to the outer diameter of the aerosol-generating article. Preferably, the outer diameter of the upstream section or upstream element thereof is between 5 and 8 mm, more preferably between 5.25 and 7.5 mm, more preferably between 5.5 and 7 mm.

Preferably, the upstream section or upstream element has a length of at least 2 mm, more preferably at least 3 mm, more preferably at least 4 mm.

Preferably, the upstream section or upstream element has a length of between 2 and 10mm, more preferably between 3 and 8 mm, more preferably between 2 and 6 mm, more preferably between 3 and 6 mm, more preferably between 4 and 8 mm, more preferably between 4 and 6 mm. In a particularly preferred embodiment, the upstream section or upstream element has a length of 5 mm. The length of the upstream section or upstream element may advantageously be varied in order to provide a desired overall length of the aerosol-generating article. For example, where it is desired to reduce the length of one of the other components of the aerosol-generating article, the length of the upstream section or upstream element may be increased so as to maintain the same overall length of the article.

In addition, for articles intended for external heating, the length of the upstream section or upstream element thereof may be used to control the position of the aerosol-generating article within the cavity of the aerosol-generating device. This may advantageously ensure that the position of the aerosol-generating substrate within the cavity may be optimised for heating, and also that the position of any ventilation may be optimised.

The upstream section is preferably defined by a wrapper, such as a rod wrapper. The wrapper defining the upstream section is preferably a rigid stick wrapper, for example, a stick wrapper having a basis weight of at least 80 grams per square meter (gsm) or at least 100gsm or at least 110 gsm. This provides structural rigidity to the upstream section.

The upstream section is preferably connected to the strip of aerosol-generating substrate and optionally at least part of the downstream section by means of an outer wrapper as described herein.

As mentioned above, the aerosol-generating article according to the invention comprises a downstream section downstream of the strip of aerosol-generating substrate. The downstream section is preferably located immediately downstream of the strip of aerosol-generating substrate. The downstream section of the aerosol-generating article preferably extends between the strip of aerosol-generating substrate and the downstream end of the aerosol-generating article. The downstream section may include one or more elements, each of which will be described in more detail within this disclosure.

The length of the downstream section may be at least 40 millimeters. The length of the downstream section may be at least 45 millimeters. The downstream section may be greater than 45 millimeters in length. The length of the downstream section may be at least 48 millimeters. The downstream section may be at least 50 millimeters in length.

The length of the downstream section may be less than 75 millimeters. The length of the downstream section may be equal to or less than 70 millimeters. The length of the downstream section may be equal to or less than 65 millimeters.

For example, the length of the downstream section may be between 40 and 75 millimeters, or between 45 and 75 millimeters, or between 48 and 75 millimeters, or between 50 and 75 millimeters. In other embodiments, the length of the downstream section may be between 40 millimeters and 70 millimeters, or between 45 millimeters and 70 millimeters, or between 48 millimeters and 70 millimeters, or between 50 millimeters and 70 millimeters. In other embodiments, the length of the downstream section may be between 40 millimeters and 65 millimeters, or between 45 millimeters and 65 millimeters, or between 48 millimeters and 65 millimeters, or between 50 millimeters and 65 millimeters.

Providing a relatively long downstream section ensures that when the aerosol-generating article is received in the aerosol-generating device, a suitable length of the article protrudes from the aerosol-generating device. This suitable protruding length facilitates easy insertion and extraction of the article from the device, which also ensures proper insertion of the upstream portion of the article into the device, in particular during insertion, with reduced risk of damage.

The ratio between the length of the downstream section and the overall length of the aerosol-generating article may be less than 0.85. Preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be less than 0.80. More preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be less than 0.75. Even more preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be less than 0.70.

The ratio between the length of the downstream section and the overall length of the aerosol-generating article may be at least 0.50. Preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be at least 0.55. More preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be at least 0.60. Even more preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be at least 0.65.

In some embodiments, the ratio between the length of the downstream section and the overall length of the aerosol-generating article is from 0.50 to 0.85, preferably from 0.55 to 0.85, more preferably from 0.60 to 0.85, even more preferably from 0.65 to 0.85. In other embodiments, the ratio between the length of the downstream section and the overall length of the aerosol-generating article is from 0.50 to 0.80, preferably from 0.55 to 0.80, more preferably from 0.60 to 0.80, even more preferably from 0.65 to 0.80. In further embodiments, the ratio between the length of the downstream section and the overall length of the aerosol-generating article is from 0.50 to 0.75, preferably from 0.55 to 0.75, more preferably from 0.60 to 0.75, even more preferably from 0.65 to 0.75. In further embodiments, the ratio between the length of the downstream section and the overall length of the aerosol-generating article is from 0.50 to 0.70, preferably from 0.55 to 0.70, more preferably from 0.60 to 0.70, even more preferably from 0.65 to 0.70.

The ratio between the length of the downstream section and the length of the upstream section may be less than 30. Preferably, the ratio between the length of the downstream section and the length of the upstream section may be less than 20. More preferably, the ratio between the length of the downstream section and the length of the upstream section may be less than 15. Even more preferably, the ratio between the length of the downstream section and the length of the upstream section may be less than 10.

The ratio between the length of the downstream section and the length of the upstream section may be at least 4. Preferably, the ratio between the length of the downstream section and the length of the upstream section may be at least 5. More preferably, the ratio between the length of the downstream section and the length of the upstream section may be at least 6. Even more preferably, the ratio between the length of the downstream section and the length of the upstream section may be at least 7.

In some embodiments, the ratio between the length of the downstream section and the length of the upstream section is 4 to 30, preferably 5 to 30, more preferably 6 to 30, even more preferably 7 to 18. In other embodiments, the ratio between the length of the downstream section and the length of the upstream section is 4 to 20, preferably 5 to 20, more preferably 6 to 20, even more preferably 7 to 20. In further embodiments, the ratio between the length of the downstream section and the length of the upstream section is 4 to 15, preferably 5 to 15, more preferably 6 to 15, even more preferably 7 to 15. In further embodiments, the ratio between the length of the downstream section and the length of the upstream section is 4 to 10, preferably 5 to 10, more preferably 6 to 10, even more preferably 7 to 10.

Preferably, the ratio between the length of the downstream section and the length of the strip of aerosol-generating substrate is at least 1.0. More preferably, the ratio between the length of the downstream section and the length of the strip of aerosol-generating substrate is at least 1.25. More preferably, the ratio between the length of the downstream section and the length of the strip of aerosol-generating substrate is at least 1.5. More preferably, the ratio between the length of the downstream section and the length of the strip of aerosol-generating substrate is at least 1.75.

The ratio between the length of the downstream section and the length of the strip of aerosol-generating substrate is preferably less than 3.5. Preferably, the ratio between the length of the downstream section and the length of the strip of aerosol-generating substrate is less than 3.25. More preferably, the ratio between the length of the downstream section and the length of the strip of aerosol-generating substrate is less than 3.0. Even more preferably, the ratio between the length of the downstream section and the length of the strip of aerosol-generating substrate is less than 2.75.

In some embodiments, the ratio between the length of the downstream section and the length of the strip of aerosol-generating substrate is from 1.0 to 3.5, preferably from 1.25 to 3.5, more preferably from 1.50 to 3.5, even more preferably from 1.75 to 3.5. In other embodiments, the ratio between the length of the downstream section and the length of the strip of aerosol-generating substrate is from 1.0 to 3.25, preferably from 1.25 to 3.25, more preferably from 1.50 to 3.25, even more preferably from 1.75 to 3.25. In further embodiments, the ratio between the length of the downstream section and the length of the strip of aerosol-generating substrate is from 1.0 to 3.0, preferably from 1.25 to 3.0, more preferably from 1.50 to 3.0, even more preferably from 1.75 to 3.0. In further embodiments, the ratio between the length of the downstream section and the length of the strip of aerosol-generating substrate is from 1.0 to 2.75, preferably from 1.25 to 2.75, more preferably from 1.50 to 2.75, even more preferably from 1.75 to 2.75.

Preferably, the downstream section of the aerosol-generating article according to the invention comprises a hollow tubular cooling element arranged downstream of the strip of aerosol-generating substrate. The hollow tubular cooling element may advantageously provide an aerosol-cooling element for the aerosol-generating article.

The hollow tubular cooling element is arranged immediately downstream of the strip of aerosol-generating substrate. In other words, the hollow tubular cooling element may abut the downstream end of the strip of aerosol-generating substrate. The hollow tubular cooling element may define an upstream end of a downstream section of the aerosol-generating article. The downstream end of the aerosol-generating article may coincide with the downstream end of the downstream section. In some embodiments, the downstream section of the aerosol-generating article comprises a single hollow tubular element. In other words, the downstream section of the aerosol-generating article may comprise only one hollow tubular element. In other embodiments, as described below, the downstream section includes two or more hollow tubular elements.

As used throughout this disclosure, the term "hollow tubular element" refers to a generally elongated element that defines a lumen or airflow path along its longitudinal axis. In particular, the term "tubular" will be used hereinafter to refer to a tubular element having a substantially cylindrical cross section and defining at least one air flow conduit establishing uninterrupted fluid communication between an upstream end of the tubular element and a downstream end of the tubular element. However, it should be understood that alternative geometries (e.g., alternative cross-sectional shapes) of the tubular element may be possible. The hollow tubular cooling element may be a single discrete element of the aerosol-generating article having a defined length and thickness.

The internal volume defined by the hollow tubular cooling element may be at least 100 cubic millimeters. In other words, the volume of the cavity or lumen defined by the hollow tubular cooling element may be at least 100 cubic millimeters. Preferably, the internal volume defined by the hollow tubular cooling element may be at least 300 cubic millimeters. The internal volume defined by the hollow tubular cooling element may be at least 700 cubic millimeters.

The internal volume defined by the hollow tubular cooling element may be less than or equal to 1200 cubic millimeters. Preferably, the internal volume defined by the hollow tubular cooling element may be less than or equal to 1000 cubic millimeters. The internal volume defined by the hollow tubular cooling element may be less than or equal to 900 cubic millimeters.

The internal volume defined by the hollow tubular cooling element may be between 100 and 1200 cubic millimeters. Preferably, the internal volume defined by the hollow tubular cooling element may be between 300 and 1000 cubic millimeters. The internal volume defined by the hollow tubular cooling element may be between 700 and 900 cubic millimeters.

In the context of the present invention, a hollow tubular cooling element provides an unrestricted flow channel. This means that the hollow tubular cooling element provides a negligible level of resistance to suction (RTD). The term "negligible RTD level" is used to describe hollow tubular cooling elements having RTDs less than 1 millimeter H ₂ O/10 millimeters in length, preferably less than 0.4 millimeter H ₂ O/10 millimeters in length, and more preferably less than 0.1 millimeter H ₂ O/10 millimeters in length.

The RTD of the hollow tubular cooling element is preferably less than or equal to 10 mm H ₂ O. More preferably, the RTD of the hollow tubular cooling element is less than or equal to 5mm H ₂ O. Even more preferably, the RTD of the hollow tubular cooling element is less than or equal to 2.5 mm H ₂ O. Even more preferably, the RTD of the hollow tubular cooling element is less than or equal to 2 millimeters H ₂ O. Even more preferably, the RTD of the hollow tubular cooling element is less than or equal to 1 millimeter H ₂ O.

The RTD of the hollow tubular cooling element may be at least 0mm H ₂ O, or at least 0.25 mm H ₂ O, or at least 0.5 mm H ₂ O, or at least 1mm H ₂ O.

In some embodiments, the hollow tubular cooling element has an RTD of 0mm H ₂ O to 10 mm H ₂ O, preferably 0.25 mm H ₂ O to 10 mm H ₂ O, Preferably 0.5 mm H ₂ O to 10 mm H ₂ O. In other embodiments, the hollow tubular cooling element has an RTD of 0mm H ₂ O to 5mm H ₂ O, preferably 0.25 mm H ₂ O to 5mm H ₂ O, Preferably 0.5 mm H ₂ O to 5mm H ₂ O. in other embodiments, the RTD of the hollow tubular cooling element is 1 millimeter H ₂ O to 5 millimeters H ₂ O. In further embodiments, the hollow tubular cooling element has an RTD of 0mm H ₂ O to 2.5 mm H ₂ O, preferably 0.25 mm H ₂ O to 2.5 mm H ₂ O, more preferably from 0.5 mm H ₂ O to 2.5 mm H ₂ O. in further embodiments, the hollow tubular cooling element has an RTD of 0mm H ₂ O to 2mm H ₂ O, preferably 0.25mm H ₂ O to 2mm H ₂ O, More preferably from 0.5 mm H ₂ O to 2 mm H ₂ O. In a particularly preferred embodiment, the RTD of the hollow tubular cooling element is 0mm H ₂ O.

In an aerosol-generating article according to the invention, the overall RTD of the article is substantially dependent on the RTD of the rod and optionally on the RTD of the downstream and/or upstream elements. This is because the hollow tubular cooling element is substantially empty and thus substantially only minimally affects the overall RTD of the aerosol-generating article.

Thus, the flow channel should be free of any components that would impede the flow of air in the longitudinal direction. Preferably, the flow channel is substantially empty, and particularly preferably the flow channel is empty.

As will be described in more detail within this disclosure, the aerosol-generating article may include a ventilation zone at a location along the downstream section. In some embodiments, the aerosol-generating article may comprise a ventilation zone at a location along the hollow tubular cooling element. This or any ventilation zone may extend through the outer circumferential wall of the hollow tubular cooling element. Thus, fluid communication is established between the flow channel defined by the interior of the hollow tubular cooling element and the external environment. The ventilation zone is further described within this disclosure.

Preferably, the hollow tubular cooling element has a length of at least 20 mm. More preferably, the hollow tubular cooling element has a length of at least 30 mm. The hollow tubular cooling element may have a length of at least 40 mm. More preferably, the hollow tubular cooling element has a length of at least 45 mm.

The hollow tubular cooling element preferably has a length of less than 60 mm. More preferably, the hollow tubular cooling element has a length of less than 55 mm. More preferably, the hollow tubular cooling element has a length of less than 50 mm.

For example, the hollow tubular cooling element may have a length between 20 and 60 millimeters, or between 30 and 60 millimeters, or between 40 and 60 millimeters, or between 45 and 60 millimeters. In other embodiments, the hollow tubular cooling element may have a length between 20 millimeters and 55 millimeters, or between 30 millimeters and 55 millimeters, or between 40 millimeters and 55 millimeters, or between 45 millimeters and 55 millimeters. In other embodiments, the hollow tubular cooling element may have a length between 20 millimeters and 50 millimeters, or between 30 millimeters and 50 millimeters, or between 40 millimeters and 50 millimeters, or between 45 millimeters and 50 millimeters.

A relatively long hollow tubular cooling element provides and defines a relatively long inner cavity downstream of the strip of aerosol-generating substrate within the aerosol-generating article. As discussed in this disclosure, providing a cavity downstream (preferably immediately downstream) of an aerosol-generating substrate enhances nucleation of aerosol particles generated by the substrate. Providing a relatively long cavity maximizes such nucleation benefits, thereby improving aerosol formation and cooling.

Preferably, the ratio between the length of the hollow tubular cooling element and the length of the strip of aerosol-generating substrate is at least 1.0. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the strip of aerosol-generating substrate is at least 1.25. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the strip of aerosol-generating substrate is at least 1.5. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the strip of aerosol-generating substrate is at least 1.75.

The ratio between the length of the hollow tubular cooling element and the length of the strip of aerosol-generating substrate is preferably less than 3.5. Preferably, the ratio between the length of the hollow tubular cooling element and the length of the strip of aerosol-generating substrate is less than 3.25. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the strip of aerosol-generating substrate is less than 3.0. Even more preferably, the ratio between the length of the hollow tubular cooling element and the length of the strip of aerosol-generating substrate is less than 2.75.

In some embodiments, the ratio between the length of the hollow tubular cooling element and the length of the strip of aerosol-generating substrate is from 1.0 to 3.5, preferably from 1.25 to 3.5, more preferably from 1.50 to 3.5, even more preferably from 1.75 to 3.5. In other embodiments, the ratio between the length of the hollow tubular cooling element and the length of the strip of aerosol-generating substrate is from 1.0 to 3.25, preferably from 1.25 to 3.25, more preferably from 1.50 to 3.25, even more preferably from 1.75 to 3.25. In a further embodiment, the ratio between the length of the hollow tubular cooling element and the length of the strip of aerosol-generating substrate is from 1.0 to 3.0, preferably from 1.25 to 3.0, more preferably from 1.50 to 3.0, even more preferably from 1.75 to 3.0. In a further embodiment, the ratio between the length of the hollow tubular cooling element and the length of the strip of aerosol-generating substrate is from 1.0 to 2.75, preferably from 1.25 to 2.75, more preferably from 1.50 to 2.75, even more preferably from 1.75 to 2.75.

The ratio between the length of the hollow tubular cooling element and the length of the downstream section may be less than 1. Preferably, the ratio between the length of the hollow tubular cooling element and the length of the downstream section may be less than 0.90. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the downstream section may be less than 0.85. Even more preferably, the ratio between the length of the hollow tubular cooling element and the length of the downstream section may be less than 0.80.

The ratio between the length of the hollow tubular cooling element and the length of the downstream section may be at least 0.35. Preferably, the ratio between the length of the hollow tubular cooling element and the length of the downstream section may be at least 0.45. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the downstream section may be at least 0.50. Even more preferably, the ratio between the length of the hollow tubular cooling element and the length of the downstream section may be at least 0.60.

In some embodiments, the ratio between the length of the hollow tubular cooling element and the length of the downstream section is 0.35 to 1, preferably 0.45 to 1, more preferably 0.50 to 1, even more preferably 0.60 to 1. In other embodiments, the ratio between the length of the hollow tubular cooling element and the length of the downstream section is 0.35 to 0.90, preferably 0.45 to 0.90, more preferably 0.50 to 0.90, even more preferably 0.60 to 0.90. In further embodiments, the ratio between the length of the hollow tubular cooling element and the length of the downstream section is 0.35 to 0.85, preferably 0.45 to 0.85, more preferably 0.50 to 0.85, even more preferably 0.60 to 0.85. For example, the ratio between the length of the hollow tubular cooling element and the length of the downstream section is preferably 0.75.

The ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article may be less than or equal to 0.80. Preferably, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article may be less than or equal to 0.75. More preferably, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article may be less than or equal to 0.70. Even more preferably, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article may be less than or equal to 0.65.

The ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article may be at least 0.40. Preferably, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article may be at least 0.45. More preferably, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article may be at least 0.50. Even more preferably, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article may be at least 0.6.

In some embodiments, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article is from 0.40 to 0.80, preferably from 0.45 to 0.80, more preferably from 0.50 to 0.80, even more preferably from 0.60 to 0.80. In other embodiments, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article is from 0.40 to 0.75, preferably from 0.45 to 0.75, more preferably from 0.50 to 0.75, even more preferably from 0.60 to 0.75. In a further embodiment, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article is from 0.40 to 0.70, preferably from 0.45 to 0.70, more preferably from 0.50 to 0.70, even more preferably from 0.60 to 0.70. In a further embodiment, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article is from 0.40 to 0.65, preferably from 0.45 to 0.65, more preferably from 0.50 to 0.65, even more preferably from 0.60 to 0.65.

Providing a downstream section or hollow tubular cooling element having the above ratio maximizes aerosol cooling and formation benefits of having a relatively long hollow tubular cooling element while providing a sufficient amount of filtration for an aerosol-generating article configured to heat but not burn. Furthermore, providing a longer hollow tubular cooling element may advantageously reduce the effective RTD of the downstream section of the aerosol-generating article, which is primarily defined by the RTD of the downstream filter segment.

The thickness of the outer peripheral wall of the hollow tubular cooling element (in other words, the wall thickness) may be at least 100 micrometers. The wall thickness of the hollow tubular cooling element may be at least 150 microns. The wall thickness of the hollow tubular cooling element may be at least 200 micrometers, preferably at least 250 micrometers, and even more preferably at least 500 micrometers (or 0.5 millimeters).

The wall thickness of the hollow tubular cooling element may be less than or equal to 2 millimeters, preferably less than or equal to 1.5 millimeters, and even more preferably less than or equal to 1.25 millimeters. The wall thickness of the hollow tubular cooling element may be less than or equal to 1 millimeter. The hollow tubular cooling element may have a wall thickness of less than or equal to 500 micrometers.

The wall thickness of the hollow tubular cooling element may be between 100 micrometers and 2 millimeters, preferably between 150 micrometers and 1.5 millimeters, even more preferably between 200 micrometers and 1.25 millimeters.

Preferably, the wall thickness of the hollow tubular cooling element is 250 micrometers (0.25 millimeters).

At the same time, keeping the thickness of the outer peripheral wall of the hollow tubular cooling element relatively low ensures that the total internal volume of the hollow tubular cooling element (which makes the aerosol available for starting the nucleation process once the aerosol components leave the strip of aerosol-generating substrate) and that the cross-sectional surface area of the hollow tubular cooling element is effectively maximized, while ensuring that the hollow tubular cooling element has the necessary structural strength to prevent collapse of the aerosol-generating article and to provide some support for the strip of aerosol-generating substrate and to ensure that the RTD of the hollow tubular cooling element is minimized. A larger value of the cross-sectional surface area of the cavity of the hollow tubular cooling element is understood to be associated with a reduced velocity of the aerosol-generating article-travelling aerosol flow, which is also expected to facilitate aerosol nucleation. Furthermore, it appears that by using hollow tubular cooling elements having a relatively low thickness, ventilation air may be substantially prevented from diffusing before it is contacted and mixed with the aerosol flow, which is also understood to further facilitate nucleation. In practice, by providing a more controlled localized cooling of the volatile material flow, the effect of cooling on the formation of new aerosol particles can be enhanced.

The hollow tubular cooling element preferably has an outer diameter substantially equal to the outer diameter of the strip of aerosol-generating substrate and the outer diameter of the aerosol-generating article.

The hollow tubular cooling element may have an outer diameter of between 5 and 10 mm, for example between 5.5 and 9 mm or between 6 and 8mm. In a preferred embodiment, the hollow tubular cooling element has an outer diameter of less than 7 millimeters.

The hollow tubular cooling element may have an inner diameter. Preferably, the hollow tubular cooling element may have a constant inner diameter along the length of the hollow tubular cooling element. However, the inner diameter of the hollow tubular cooling element may vary along the length of the hollow tubular cooling element.

The hollow tubular cooling element may have an inner diameter of at least 2 mm. For example, the hollow tubular cooling element may have an inner diameter of at least 3 millimeters, at least 4 millimeters, or at least 5 millimeters.

Providing a hollow tubular cooling element having an inner diameter as described above may advantageously provide the hollow tubular cooling element with sufficient rigidity and strength.

The hollow tubular cooling element may have an inner diameter of no more than 10 mm. For example, the hollow tubular cooling element may have an inner diameter of no more than 9 millimeters, no more than 8 millimeters, or no more than 7 millimeters.

Providing a hollow tubular cooling element having an inner diameter as described above may advantageously reduce the pumping resistance of the hollow tubular cooling element.

The hollow tubular cooling element may have an inner diameter of between 2 mm and 10 mm, between 3 mm and 9 mm, between 4 mm and 8 mm or between 5mm and 7 mm.

The ratio between the inner diameter of the hollow tubular cooling element and the outer diameter of the hollow tubular cooling element may be at least 0.8. For example, the ratio between the inner diameter of the hollow tubular cooling element and the outer diameter of the hollow tubular cooling element may be at least 0.85, at least 0.9 or at least 0.95.

The ratio between the inner diameter of the hollow tubular cooling element and the outer diameter of the hollow tubular cooling element may not exceed 0.99. For example, the ratio between the inner diameter of the hollow tubular cooling element and the outer diameter of the hollow tubular cooling element may not exceed 0.98.

The ratio between the inner diameter of the hollow tubular cooling element and the outer diameter of the hollow tubular cooling element may be 0.97.

Providing a relatively large inner diameter may advantageously reduce the pumping resistance of the hollow tubular cooling element and enhance cooling and nucleation of aerosol particles.

The lumen or cavity of the hollow tubular cooling element may have any cross-sectional shape. The lumen of the hollow tubular cooling element may have a circular cross-sectional shape.

The hollow tubular cooling element may comprise a paper-based material. The hollow tubular cooling element may comprise at least one paper layer. The paper may be very hard paper. The paper may be a curled paper, such as curled heat resistant paper or curled parchment paper.

Preferably, the hollow tubular cooling element may comprise cardboard. The hollow tubular cooling element may be a cardboard tube. The hollow tubular cooling element may be formed from cardboard. Advantageously, the cardboard is a cost-effective material that provides a balance between being deformable so as to provide ease of insertion of the article into the aerosol-generating device and being sufficiently rigid to provide proper engagement of the article with the interior of the device. Thus, the paperboard tube may provide suitable resistance to deformation or compression during use.

The hollow tubular cooling element may be a paper tube. The hollow tubular cooling element may be a tube formed from helically wound paper. The hollow tubular cooling element may be formed from a plurality of paper layers. The paper may have a basis weight of at least 50 grams per square meter, at least 60 grams per square meter, at least 70 grams per square meter, or at least 90 grams per square meter.

The hollow tubular cooling element may comprise a polymeric material. For example, the hollow tubular cooling element may comprise a polymer film. The polymer film may comprise a cellulosic film. The hollow tubular cooling element may comprise low density polyethylene (HDPE) or Polyhydroxyalkanoate (PHA) fibers. The hollow tube may comprise cellulose acetate tow.

Where the hollow tubular cooling element comprises cellulose acetate tow, the cellulose acetate tow may have a denier per filament of between 2 and 4 and a total denier of between 25 and 40.

In some embodiments, an aerosol-generating article according to the invention may comprise a ventilation zone at a location along the downstream section. In more detail, in those embodiments in which the downstream section includes a hollow tubular cooling element, the ventilation zone may be disposed at a location along the hollow tubular cooling element. Alternatively, in those embodiments in which the downstream section includes a downstream hollow tubular element, the vented zone may be disposed at a location along the downstream hollow tubular element, as described below.

Thus, the ventilation chamber is arranged downstream of the strip of aerosol-generating substrate. This provides several potential technical benefits.

First, the inventors have found that one such ventilated hollow tubular cooling element provides particularly efficient aerosol cooling. Thus, satisfactory aerosol cooling may even be achieved by means of a relatively short downstream section. This is particularly desirable as it is capable of providing an aerosol-generating article in which the aerosol-generating substrate (and in particular the tobacco-containing substrate) is heated without combustion, which combines satisfactory aerosol delivery with efficient cooling of the aerosol to a consumer-desired temperature.

Second, the inventors have surprisingly found that such rapid cooling of volatile materials released upon heating of the aerosol-generating substrate promotes enhanced nucleation of aerosol particles. This effect is particularly felt when the ventilation zone is arranged at a precisely defined position along the length of the hollow tubular cooling element with respect to other components of the aerosol-generating article, as will be described in more detail below. Indeed, the inventors have found that the beneficial effect of enhancing nucleation can significantly offset the potentially less desirable dilution effect caused by the introduction of ventilation air.

The distance between the ventilation zone and the upstream end of the upstream element may be at least 25 mm. As used herein, the term "distance between the ventilation zone and another element or portion of the aerosol-generating article" refers to a measure of distance in the longitudinal direction (i.e. in a direction extending along or parallel to the cylindrical axis of the aerosol-generating article).

Preferably, the distance between the ventilation zone and the upstream end of the upstream element is at least 26 mm. More preferably, the distance between the ventilation zone and the upstream end of the upstream element is at least 27 mm.

The distance between the ventilation zone and the upstream end of the upstream element may be less than or equal to 34 millimeters. Preferably, the distance between the ventilation zone and the upstream end of the upstream element is less than or equal to 33 mm. More preferably, the distance between the ventilation zone and the upstream end of the upstream element is less than or equal to 31 mm.

In some embodiments, the distance between the ventilation zone and the upstream end of the upstream element is 25 to 34 mm, preferably 26 to 34 mm, more preferably 27 to 34 mm.

In other embodiments, the distance between the ventilation zone and the upstream end of the upstream element is 25 to 33 mm, preferably 26 to 33 mm, more preferably 27 to 33 mm.

In further embodiments, the distance between the ventilation zone and the upstream end of the upstream element is 25 to 31 mm, preferably 26 to 31 mm, more preferably 27 to 31 mm.

In some particularly preferred embodiments, the distance between the ventilation zone and the upstream end of the upstream element is from 28 mm to 30 mm.

It has been found that an aerosol-generating article comprising a ventilation zone along the hollow tubular cooling element at a distance from the upstream end of the upstream element within the above-mentioned range has a number of benefits.

First, such articles have been observed to provide particularly satisfactory aerosol delivery to consumers, particularly where the aerosol-generating substrate comprises tobacco.

Without wishing to be bound by theory, the intense cooling caused by ambient air drawn into the cavity of the hollow tubular cooling element at the ventilation zone is understood to accelerate the condensation of droplets of aerosol-forming agent (e.g. glycerol) released from the aerosol-generating substrate upon heating. In turn, the volatile nicotine and organic acids similarly released from the tobacco substrate accumulate on the newly formed aerosol former droplets and subsequently combine to form a nicotine salt. Thus, the overall ratio of aerosol particulate phase to aerosol gas phase may be increased as compared to existing aerosol-generating articles.

Positioning the ventilation zone at a distance from the upstream end of the upstream element as described above advantageously reduces the time of flight of the volatilized nicotine before the volatilized nicotine particles reach the droplets of aerosol-forming agent. At the same time, one such positioning of the ventilation zone relative to the upstream end of the upstream element ensures that there is sufficient time and space for the accumulation of nicotine and the formation of nicotine salts to occur in significant proportion before the aerosol flow reaches the mouth of the consumer.

The ventilation zone may generally comprise a plurality of perforations through the peripheral wall of the hollow tubular cooling element. Preferably, the ventilation zone comprises at least one row of circumferential perforations. In some embodiments, the vented zone may include two circumferential rows of perforations. For example, perforations may be formed on the production line during manufacture of the aerosol-generating article. Preferably, each row of circumferential perforations comprises 8 to 30 perforations.

The aerosol-generating article according to the invention may have a ventilation level of at least 2%.

Throughout the present specification, the term "ventilation level" is used to denote the volume ratio between the air flow (ventilation air flow) entering the aerosol-generating article via the ventilation zone and the sum of the aerosol air flow and the ventilation air flow. The greater the ventilation level, the higher the dilution of the aerosol stream delivered to the consumer. The aerosol-generating article preferably has a ventilation level of at least 5%, more preferably at least 10%, even more preferably at least 12% or at least 15%.

The aerosol-generating article according to the invention may have a ventilation level of up to 90%. Preferably, the aerosol-generating article according to the invention has a ventilation level of less than or equal to 80%, more preferably less than or equal to 70%, even more preferably less than or equal to 60%, most preferably less than or equal to 50%.

Thus, the aerosol-generating article according to the invention may have a ventilation level of from 2% to 90%, preferably from 5% to 90%, more preferably from 10% to 90%, even more preferably from 15% to 90%. The aerosol-generating article according to the invention may have a ventilation level of from 2% to 80%, preferably from 5% to 80%, more preferably from 10% to 80%, even more preferably from 15% to 80%. The aerosol-generating article according to the invention may have a ventilation level of from 2% to 70%, preferably from 5% to 70%, more preferably from 10% to 70%, even more preferably from 15% to 70%. The aerosol-generating article according to the invention may have a ventilation level of from 2% to 60%, preferably from 5% to 60%, more preferably from 10% to 60%, even more preferably from 15% to 60%. The aerosol-generating article according to the invention may have a ventilation level of from 2% to 50%, preferably from 5% to 50%, more preferably from 10% to 50%, even more preferably from 15% to 50%. The aerosol-generating article preferably has a ventilation level of less than or equal to 30%, preferably less than or equal to 25%, more preferably less than or equal to 20%, even more preferably less than or equal to 18%.

In some embodiments, the aerosol-generating article has a ventilation level of from 10% to 30%, preferably from 12% to 30%, more preferably from 15% to 30%. In other embodiments, the aerosol-generating article has a ventilation level of from 10% to 25%, preferably from 12% to 25%, more preferably from 15% to 25%. In further embodiments, the aerosol-generating article has a ventilation level of from 10% to 20%, preferably from 12% to 20%, more preferably from 15% to 20%. In a particularly preferred embodiment, the aerosol-generating article has a ventilation level of from 10% to 18%, preferably from 12% to 18%, more preferably from 15% to 18%.

Without wishing to be bound by theory, the inventors have found that the temperature drop caused by cooler external air entering the hollow tubular cooling element via the ventilation zone can have a beneficial effect on the nucleation and growth of aerosol particles.

The formation of aerosols from gas mixtures containing various chemicals depends on subtle interactions between nucleation, evaporation and condensation and coalescence, taking into account variations in vapor concentration, temperature and velocity fields. The so-called classical nucleation theory is based on the following assumptions: a portion of the molecules in the gas phase are large enough to remain coherent for a long time with sufficient probability (e.g., half probability). These molecules represent some kind of critical, threshold molecular clusters in transient molecular aggregates, which means that on average smaller molecular clusters may quickly break down into the gas phase, while larger clusters may grow on average. Such critical clusters are considered critical nucleation cores from which droplets are expected to grow due to condensation of molecules in the vapor. Assuming that the original droplets just nucleated appear at a certain original diameter, then may grow by several orders of magnitude. This process is promoted and enhanced by the rapid cooling of the surrounding steam to cause condensation. In this regard, it should be remembered that evaporation and condensation are two aspects of the same mechanism, namely gas-liquid mass transfer. While evaporation involves a net mass transfer from the liquid droplet to the gas phase, condensation is a net mass transfer from the gas phase to the liquid droplet phase. Evaporation (or condensation) will cause the droplets to contract (or grow) without changing the number of droplets.

In this scenario, which may be more complicated by coalescence phenomena, the temperature and rate of cooling play a critical role in determining how the system responds. Generally, different cooling rates can result in significantly different time behaviors associated with liquid phase (droplet) formation, as the nucleation process is generally nonlinear. Without wishing to be bound by theory, it is hypothesized that cooling may result in a rapid increase in the number concentration of droplets followed by a strong, short increase in this growth (nucleation burst). This nucleation burst appears to be more pronounced at lower temperatures. Furthermore, it appears that a higher cooling rate may be advantageous for an earlier onset of nucleation. In contrast, a decrease in the cooling rate appears to have a beneficial effect on the final size of the aerosol droplets eventually reached.

Thus, rapid cooling caused by external air entering the hollow tubular cooling element via the ventilation zone can be advantageously used to facilitate nucleation and growth of aerosol droplets. At the same time, however, the entry of external air into the hollow tubular cooling element has the direct disadvantage of diluting the aerosol flow delivered to the consumer.

The inventors have surprisingly found how the beneficial effect of enhanced nucleation, promoted by rapid cooling induced by introducing ventilation air into the article, can significantly offset the less desirable dilution effect. Thus, satisfactory aerosol delivery values are consistently achieved with the aerosol-generating article according to the invention.

The inventors have also surprisingly found that when the ventilation level is within the above-mentioned range, the dilution effect on the aerosol, in particular as can be assessed by measuring the delivery effect of an aerosol-former (e.g. glycerol) comprised in the aerosol-generating substrate, is advantageously minimized.

In particular, ventilation levels between 10% and 20% and even more preferably between 12% and 18% have been found to yield particularly satisfactory glycerol delivery values.

Because the ventilated hollow tubular cooling element does not substantially affect the overall RTD of the aerosol-generating article, in an aerosol-generating article according to the invention, the overall RTD of the article may be advantageously fine tuned by adjusting the length and density of the strips of aerosol-generating substrate, as well as the length and optionally the length and density of any segments of filter material forming part of the downstream section (e.g., the downstream filter segment), or segments of filter material disposed upstream of the aerosol-generating substrate. Thus, an aerosol-generating article having a predetermined RTD can be consistently and highly accurately manufactured so that a satisfactory RTD level can be provided to the consumer even in the presence of ventilation.

The distance between the ventilation zone and the downstream end of the strip of aerosol-generating substrate may be at least 4mm, or at least 6mm, or at least 8 mm. Preferably, the distance between the ventilation zone and the downstream end of the strip of aerosol-generating substrate may be at least 9 mm. More preferably, the distance between the ventilation zone and the downstream end of the strip of aerosol-generating substrate may be at least 10 mm.

The distance between the ventilation zone and the downstream end of the strip of aerosol-generating substrate is preferably less than 17 mm. More preferably, the distance between the ventilation zone and the downstream end of the strip of aerosol-generating substrate is less than 16 mm. Even more preferably, the distance between the ventilation zone and the downstream end of the strip of aerosol-generating substrate is less than 16 mm. In a particularly preferred embodiment, the distance between the ventilation zone and the downstream end of the strip of aerosol-generating substrate is less than 15 mm.

In some embodiments, the distance between the ventilation zone and the downstream end of the strip of aerosol-generating substrate is from 4 mm to 17 mm, preferably from 7 mm to 17 mm, more preferably from 10 mm to 17 mm. In other embodiments, the distance between the ventilation zone and the downstream end of the strip of aerosol-generating substrate is from 8 mm to 16 mm, preferably from 9 mm to 16 mm, more preferably from 10 mm to 16 mm. In a further embodiment, the distance between the ventilation zone and the downstream end of the strip of aerosol-generating substrate is from 8 to 15 mm, preferably from 9 to 15 mm, more preferably from 10 to 15 mm. For example, the distance between the ventilation zone and the downstream end of the strip of aerosol-generating substrate may be from 10 to 14 mm, preferably from 10 to 13 mm, more preferably from 10 to 12 mm.

Positioning the ventilation zone at a distance within the above-mentioned range from the downstream end of the strip of aerosol-generating substrate has the advantage of generally ensuring that, during use, when the aerosol-generating article is inserted into the heating device, the ventilation zone is just outside the heating device, while reducing the risk of the ventilation zone being inadvertently obscured by the lips or hands of the user. In addition, it has been found that locating the ventilation zone at a distance from the downstream end of the strip of aerosol-generating substrate within the above-described range may advantageously enhance nucleation and aerosol formation and delivery.

The distance between the ventilation zone and the downstream end of the hollow tubular cooling element may be at least 3 mm. Preferably, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is at least 5 mm. More preferably, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is at least 7 mm.

The distance between the ventilation zone and the downstream end of the hollow tubular cooling element is preferably less than or equal to 14 mm. More preferably, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is less than or equal to 12 mm. Even more preferably, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is less than or equal to 10 millimeters.

In some embodiments, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is from 3 mm to 14 mm, preferably from 5mm to 14 mm, more preferably from 7 mm to 14 mm. In a further embodiment, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is 3 to 12 mm, preferably 5 to 12 mm, more preferably 7 to 12 mm. In other embodiments, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is 3 to 10 mm, preferably 5 to 10 mm, more preferably 7 to 10 mm.

Positioning the ventilation zone at a distance from the downstream end of the hollow tubular cooling element within the above-mentioned range has the advantage of generally ensuring that, during use, when the aerosol-generating article is inserted into the heating device, the ventilation zone is just outside the heating device, while reducing the risk of the ventilation zone being inadvertently obscured by the lips or hands of the user. In addition, it has been found that positioning the ventilation zone at a distance from the downstream end of the hollow tubular cooling element within the above-described range can advantageously result in relatively more uniform aerosol formation and delivery.

The distance between the ventilation zone and the downstream end of the aerosol-generating article may be at least 10 mm. Preferably, the distance between the ventilation zone and the downstream end of the aerosol-generating article is at least 12 mm. More preferably, the distance between the ventilation zone and the downstream end of the aerosol-generating article is at least 15 mm.

The distance between the ventilation zone and the downstream end of the aerosol-generating article is preferably less than or equal to 21 mm. More preferably, the distance between the ventilation zone and the downstream end of the aerosol-generating article is less than or equal to 19 mm. Even more preferably, the distance between the ventilation zone and the downstream end of the aerosol-generating article is less than or equal to 17 mm.

In some embodiments, the distance between the ventilation zone and the downstream end of the aerosol-generating article is from 10 to 21 mm, preferably from 12 to 21 mm, more preferably from 15 to 21 mm. In a further embodiment, the distance between the ventilation zone and the downstream end of the aerosol-generating article is from 10 to 19mm, preferably from 12 to 19mm, more preferably from 15 to 19 mm. In other embodiments, the distance between the ventilation zone and the downstream end of the aerosol-generating article is from 10 to 17 mm, preferably from 12 to 17 mm, more preferably from 15 to 17 mm.

Positioning the ventilation zone at a distance from the downstream end of the aerosol-generating article within the above-mentioned range has the benefit of generally ensuring that, during use, when the aerosol-generating article is partially received within the heating device, a portion of the aerosol-generating article extending outside the heating device is long enough for a consumer to comfortably hold the article between their lips while reducing the risk of the ventilation zone being inadvertently occluded by the lips or hands of the user. At the same time, evidence suggests that if the length of a portion of the aerosol-generating article extending outside the heating device is large, it may become easy to unintentionally and undesirably bend the aerosol-generating article, and this may impair the delivery of the aerosol or substantially affect the intended use of the aerosol-generating article.

As discussed in this disclosure, the downstream section may include a downstream filter segment. The downstream filter segment may extend to a downstream end of the downstream section. The downstream filter segment may be located at a downstream end of the aerosol-generating article. The downstream end of the downstream filter segment may define a downstream end of the aerosol-generating article.

The downstream filter segment may be located downstream of the hollow tubular cooling element as described above. The downstream filter segment may extend between the hollow tubular cooling element and a downstream end of the aerosol-generating article.

The downstream filter segment is preferably a solid rod, which may also be described as a "normal" rod and is non-tubular. Thus, the filter segments preferably have a substantially uniform cross-section.

The downstream filter segment is preferably formed of fibrous filter material. The fibrous filter material may be used to filter aerosols generated by the aerosol-generating substrate. Suitable fibrous filter materials will be known to the skilled person. Particularly preferably, the at least one downstream filter segment comprises a cellulose acetate filter segment formed from cellulose acetate tow.

In certain preferred embodiments, the downstream section comprises a single downstream filter segment. In an alternative embodiment, the downstream section includes two or more downstream filter segments axially aligned in end-to-end abutting relationship with each other.

The downstream filter segment may optionally include a flavoring, which may be provided in any suitable form. For example, the downstream filter segment may include one or more capsules, beads or granules of flavoring, or one or more flavor-bearing threads or filaments.

Preferably, the downstream filter segment has a low particulate filtration efficiency.

Preferably, the downstream filter segment is defined by a rod wrapper. Preferably, the downstream filter segment is not ventilated such that air does not enter the aerosol-generating article along the downstream filter segment.

The downstream filter segment is preferably connected to one or more of the adjacent upstream components of the aerosol-generating article by means of a tipping wrapper.

The downstream filter segment preferably has an outer diameter substantially equal to the outer diameter of the aerosol-generating article. The diameter of the downstream filter segment may be substantially the same as the outer diameter of the hollow tubular cooling element.

The downstream filter segment may have an outer diameter between 5 millimeters and 10 millimeters. The downstream filter segment may have a diameter between 5.5 millimeters and 9 millimeters. The downstream filter segment may have a diameter between 6 millimeters and 8 millimeters. In a preferred embodiment, the downstream filter segment has a diameter of less than 7 millimeters.

The Resistance To Draw (RTD) of a component or aerosol-generating article is measured according to ISO6565-2015 unless otherwise specified. RTD refers to the pressure required to force air through the entire length of the component. The term "pressure drop" or "pumping resistance (DRAW RESISTANCE)" of a component or article may also refer to "pumping resistance (RESISTANCE TO DRAW)". Such terms generally refer to measurements according to ISO6565-2015 typically performed in a test at a volumetric flow rate of 17.5 ml/s at the output or downstream end of the measurement component at a temperature of 22 degrees celsius, a pressure of 101 kPa (about 760 torr) and a relative humidity of 60%. Conditions for smoking and smoking machine specifications are set forth in ISO standard 3308 (ISO 3308:2000). The conditioned and tested atmospheres are set forth in ISO standard 3402 (ISO 3402:1999).

The downstream section may have a Resistance To Draw (RTD) of at least 0 millimeters H ₂ O. The RTD of the downstream section may be at least 3 millimeters H ₂ O. The RTD of the downstream section may be at least 6 millimeters H ₂ O.

The RTD of the downstream section may be no greater than 12 millimeters H ₂ O. The RTD of the downstream section may be no greater than 11 millimeters H ₂ O. The RTD of the downstream section may be no greater than 10 millimeters H ₂ O.

The suction resistance of the downstream section may be greater than or equal to 0 millimeters H ₂ O and less than 12 millimeters H ₂ O. Preferably, the suction resistance of the downstream section may be greater than or equal to 3 millimeters H ₂ O and less than 12 millimeters H ₂ O. The suction resistance of the downstream section may be greater than or equal to 0 millimeters H ₂ O and less than 11 millimeters H ₂ O. Even more preferably, the suction resistance of the downstream section may be greater than or equal to 3 millimeters H ₂ O and less than 11 millimeters H ₂ O. Even more preferably, the suction resistance of the downstream section may be greater than or equal to 6 millimeters H ₂ O and less than 10 millimeters H ₂ O. Preferably, the suction resistance of the downstream section may be 8 millimeters H ₂ O.

The suction Resistance (RTD) characteristics of the downstream section may be attributed entirely or primarily to the RTD characteristics of the downstream filter segment of the downstream section. In other words, the RTD of the downstream filter segment of the downstream section may fully define the RTD of the downstream section.

The downstream filter segment may have a Resistance To Draw (RTD) of at least 0 millimeters H ₂ O. The RTD of the downstream filter segment may be at least 3 millimeters H ₂ O. The RTD of the downstream filter segment may be at least 6 millimeters H ₂ O.

The RTD of the downstream filter segment may be no greater than 12 millimeters H ₂ O. The RTD of the downstream filter segment may be no greater than 11 millimeters H ₂ O. The RTD of the downstream filter segment may be no greater than 10 millimeters H ₂ O.

The suction resistance of the downstream filter segment may be greater than or equal to 0 millimeters H ₂ O and less than 12 millimeters H ₂ O. Preferably, the suction resistance of the downstream filter segment may be greater than or equal to 3 millimeters H ₂ O and less than 12 millimeters H ₂ O. The suction resistance of the downstream filter segment may be greater than or equal to 0 millimeters H ₂ O and less than 11 millimeters H ₂ O. Even more preferably, the suction resistance of the downstream filter segment may be greater than or equal to 3 millimeters H ₂ O and less than 11 millimeters H ₂ O. Even more preferably, the suction resistance of the downstream filter segment may be greater than or equal to 6 millimeters H ₂ O and less than 10 millimeters H ₂ O. Preferably, the suction resistance of the downstream filter segment may be 8 millimeters H ₂ O.

As described above, the downstream filter segment may be formed from a fibrous filter material. The downstream filter segment may be formed from a porous material. The downstream filter segment may be formed of a biodegradable material. The downstream filter segment may be formed from a cellulosic material such as cellulose acetate. For example, the downstream filter segment may be formed from bundled cellulose acetate fibers having a denier per filament of between 10 and 15. For example, the downstream filter segment is formed from a relatively low density cellulose acetate tow (such as a cellulose acetate tow comprising fibers of denier per filament of 12).

The downstream filter segment may be formed from a polylactic acid-based material. The downstream filter segment may be formed of a bio-plastic material, preferably a starch-based bio-plastic material. The downstream filter segment may be made by injection molding or by extrusion. A bio-plastic based material is advantageous because it can provide a downstream filter segment structure that is simple and inexpensive to manufacture, has a specific and complex cross-sectional profile, and can include a plurality of relatively large gas flow channels extending through the downstream filter segment material that provide suitable RTD characteristics.

The downstream filter segment may be formed from a sheet of suitable material that has been crimped, pleated, gathered, woven or folded into elements defining a plurality of longitudinally extending channels. Sheets of such suitable materials may be formed from paper, paperboard, polymers (e.g., polylactic acid), or any other cellulose-based, paper-based, or bioplastic-based material. The cross-sectional profile of such downstream filter segments may show the channels as randomly oriented.

The downstream filter segment may be formed in any other suitable manner. For example, the downstream filter segment may be formed from a bundle of longitudinally extending tubes. The longitudinally extending tube may be formed of polylactic acid. The downstream filter segments may be formed by extrusion, molding, lamination, injection molding, or shredding of a suitable material. Thus, it is preferred that there be a low pressure drop (or RTD) from the upstream end of the downstream filter segment to the downstream end of the downstream filter segment.

The downstream filter segment may be at least 5 millimeters in length. The downstream filter segment may be at least 10 millimeters in length. The downstream filter segment may have a length of less than 25 millimeters. The downstream filter segment may have a length of less than 20 millimeters. For example, the length of the downstream filter segment may be between 5 millimeters and 25 millimeters, or between 10 millimeters and 25 millimeters, or between 5 millimeters and 20 millimeters, or between 10 millimeters and 20 millimeters.

The ratio between the length of the downstream filter segment and the length of the downstream section may be less than or equal to 0.55. Preferably, the ratio between the length of the downstream filter segment and the length of the downstream section may be less than or equal to 0.45. More preferably, the ratio between the length of the downstream filter segment and the length of the downstream section may be less than or equal to 0.35. Even more preferably, the ratio between the length of the downstream filter segment and the length of the downstream section may be less than or equal to 0.25.

The ratio between the length of the downstream filter segment and the length of the downstream section may be at least 0.05. Preferably, the ratio between the length of the downstream filter segment and the length of the downstream section may be at least 0.10. More preferably, the ratio between the length of the downstream filter segment and the length of the downstream section may be at least 0.15. Even more preferably, the ratio between the length of the downstream filter segment and the length of the downstream section may be at least 0.20.

In some embodiments, the ratio between the length of the downstream filter segment and the length of the downstream section is 0.05 to 0.55, preferably 0.10 to 0.55, more preferably 0.15 to 0.55, even more preferably 0.20 to 0.55. In other embodiments, the ratio between the length of the downstream filter segment and the length of the downstream section is 0.05 to 0.45, preferably 0.10 to 0.45, more preferably 0.15 to 0.45, even more preferably 0.20 to 0.45. In further embodiments, the ratio between the length of the downstream filter segment and the length of the downstream section is 0.05 to 0.35, preferably 0.10 to 0.35, more preferably 0.15 to 0.35, even more preferably 0.20 to 0.35. For example, the ratio between the length of the downstream filter segment and the length of the downstream section is preferably between 0.20 and 0.25, more preferably the ratio between the length of the downstream filter segment and the length of the downstream section may be 0.25.

The ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be less than or equal to 0.40. Preferably, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be less than or equal to 0.30. More preferably, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be less than or equal to 0.25. Even more preferably, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be less than or equal to 0.20.

The ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be at least 0.05. Preferably, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be at least 0.07. More preferably, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be at least 0.10. Even more preferably, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be at least 0.15.

In some embodiments, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article is from 0.05 to 0.40, preferably from 0.07 to 0.40, more preferably from 0.10 to 0.40, even more preferably from 0.15 to 0.40. In other embodiments, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article is from 0.05 to 0.30, preferably from 0.07 to 0.30, more preferably from 0.10 to 0.30, even more preferably from 0.15 to 0.30. In further embodiments, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article is from 0.05 to 0.25, preferably from 0.07 to 0.25, more preferably from 0.10 to 0.25, even more preferably from 0.15 to 0.25. For example, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be between 0.15 and 0.20, more preferably the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be 0.16.

In embodiments in which the downstream section includes a hollow tubular cooling element and a downstream filter segment, the ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be at least 1.25. In other words, the length of the hollow tubular cooling element may be equal to 125% of the length of the downstream filter segment. The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be at least 1.5. The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be at least 2.

The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be equal to or less than 8.5. The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be equal to or less than 6. The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be equal to or less than 4.

The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be between 1.25 and 8.5. The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be between 1.5 and 6. The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be between 2 and 4.

In certain preferred embodiments, the downstream section may include a ventilation zone at a location downstream of the downstream filter segment. In one example, a vent zone may be provided at a location downstream of the downstream filter segment rather than at a location along the hollow tubular cooling element. In another example, a ventilation zone at a location downstream of the downstream filter segment may be provided in addition to a ventilation zone provided at a location on the hollow tubular cooling element.

The ventilation zone downstream of the filter segment may include a plurality of perforations. Preferably, the ventilation zone downstream of the filter segment comprises at least one row of circumferential perforations. In some embodiments, the ventilation zone downstream of the filter segment may include two circumferential rows of perforations. For example, perforations may be formed on the production line during manufacture of the aerosol-generating article. Preferably, each row of circumferential perforations comprises 8 to 30 perforations.

The downstream section may also include one or more additional hollow tubular elements.

In certain embodiments, the downstream section may comprise a hollow tubular support element upstream of the hollow tubular cooling element described above. Preferably, the hollow tubular support element is adjacent to the downstream end of the strip of aerosol-generating substrate. Preferably, the hollow tubular support element abuts the upstream end of the hollow tubular cooling element. Preferably, the hollow tubular support element and the hollow tubular cooling element are adjacent to each other and together provide a hollow tubular section within the downstream section.

The hollow tubular support element may be formed of any suitable material or combination of materials. For example, the support element may be formed from one or more materials selected from the group consisting of: cellulose acetate; a paperboard; curled papers such as curled heat resistant papers or curled parchment papers; and polymeric materials such as Low Density Polyethylene (LDPE). In a preferred embodiment, the support element is formed from cellulose acetate. Other suitable materials include Polyhydroxyalkanoate (PHA) fibers. In a preferred embodiment, the hollow tubular support element comprises a hollow acetate tube.

The hollow tubular support element preferably has an outer diameter substantially equal to the outer diameter of the strip of aerosol-generating substrate and the outer diameter of the aerosol-generating article.

The hollow tubular support element may have an outer diameter of between 5 and 10 mm, for example between 5.5 and 9 mm or between 6 and 8mm. In a preferred embodiment, the hollow tubular support element has an outer diameter of less than 7 millimeters.

The hollow tubular support element may have a wall thickness of at least 1 mm, preferably at least 1.5mm, more preferably at least 2mm.

The hollow tubular support element may have a length of at least 5 mm. Preferably, the support element has a length of at least 6mm, more preferably at least 7 mm.

The hollow tubular support element may have a length of less than 15 mm. Preferably, the hollow tubular support element has a length of less than 12 mm, more preferably less than 10 mm.

In some embodiments, the support element has a length of 5 to 15 millimeters, preferably 6 to 15 millimeters, more preferably 7 to 15 millimeters. In other embodiments, the support element has a length of 5 to 12 mm, preferably 6 to 12 mm, more preferably 7 to 12 mm. In further embodiments, the support element has a length of 5 to 10 mm, preferably 6 to 10 mm, more preferably 7 to 10 mm.

Preferably, the hollow tubular section has a length of at least 20 mm. More preferably, the hollow tubular section has a length of at least 30 mm. The hollow tubular section may be at least 40 millimeters in length. More preferably, the hollow tubular section has a length of at least 45 mm.

The length of the hollow tubular section is preferably less than 60 mm. More preferably, the hollow tubular section has a length of less than 55 mm. More preferably, the hollow tubular section has a length of less than 50 mm.

For example, the length of the hollow tubular section may be between 20 and 60 millimeters, or between 30 and 60 millimeters, or between 40 and 60 millimeters, or between 45 and 60 millimeters. In other embodiments, the length of the hollow tubular section may be between 20 and 55 millimeters, or between 30 and 55 millimeters, or between 40 and 55 millimeters, or between 45 and 55 millimeters. In other embodiments, the length of the hollow tubular section may be between 20 and 50 millimeters, or between 30 and 50 millimeters, or between 40 and 50 millimeters, or between 45 and 50 millimeters.

Alternatively or in addition to the hollow tubular support element, the downstream section may also comprise a downstream hollow tubular element downstream of the hollow tubular cooling element. The downstream hollow tubular element may be disposed immediately adjacent to the hollow tubular cooling element. Alternatively and preferably, the downstream hollow tubular element is separated from said hollow tubular cooling element by at least one other component. For example, the downstream section may include a downstream filter segment between the hollow tubular cooling element and the downstream hollow tubular element. Thus, the downstream hollow tubular element is located downstream of the downstream filter segment, and preferably, the downstream hollow tubular element abuts the downstream end of the downstream filter segment.

Preferably, the downstream hollow tubular element extends to the downstream end of the downstream section. Thus, the downstream hollow tubular element preferably extends to the downstream end of the aerosol-generating article. In certain embodiments, additional downstream hollow tubular elements may be provided such that the downstream section includes two adjacent downstream hollow tubular elements downstream of the downstream filter segment.

The RTD of the downstream hollow tubular element is preferably less than or equal to 10 mm H ₂ O. More preferably, the RTD of the downstream hollow tubular element is less than or equal to 5mm H ₂ O. Even more preferably, the RTD of the downstream hollow tubular element is less than or equal to 2.5 mm H ₂ O. Even more preferably, the RTD of the downstream hollow tubular element is less than or equal to 2mm H ₂ O. Even more preferably, the RTD of the downstream hollow tubular element is less than or equal to 1 millimeter H ₂ O.

The RTD of the downstream hollow tubular element may be at least 0mm H ₂ O, or at least 0.25 mm H ₂ O, or at least 0.5 mm H ₂ O, or at least 1mm H ₂ O.

In some embodiments, the RTD of the downstream hollow tubular element is from 0mm H ₂ O to 10mm H ₂ O, preferably from 0.25 mm H ₂ O to 10mm H ₂ O, Preferably 0.5 mm H ₂ O to 10 mm H ₂ O. In other embodiments, the RTD of the downstream hollow tubular element is from 0mm H ₂ O to 5mm H ₂ O, preferably from 0.25 mm H ₂ O to 5mm H ₂ O, Preferably 0.5 mm H ₂ O to 5mm H ₂ O. in other embodiments, the RTD of the downstream hollow tubular element is 1 millimeter H ₂ O to 5 millimeters H ₂ O. In further embodiments, the RTD of the downstream hollow tubular element is from 0mm H ₂ O to 2.5 mm H ₂ O, preferably from 0.25 mm H ₂ O to 2.5 mm H ₂ O, more preferably from 0.5 mm H ₂ O to 2.5 mm H ₂ O. In further embodiments, the RTD of the downstream hollow tubular element is from 0mm H ₂ O to 2 mm H ₂ O, preferably from 0.25 mm H ₂ O to 2 mm H ₂ O, More preferably from 0.5 mm H ₂ O to 2 mm H ₂ O. in a particularly preferred embodiment, the RTD of the downstream hollow tubular element is 0mm H ₂ O.

Thus, the flow channel of the downstream hollow tubular element should be free of any components that would impede the flow of air in the longitudinal direction. Preferably, the flow channel is substantially empty, and particularly preferably the flow channel is empty.

Preferably, the downstream hollow tubular element has a length of at least 3 mm. More preferably, the downstream hollow tubular element has a length of at least 4 mm. The length of the downstream hollow tubular element may be at least 5 mm. More preferably, the length of the downstream hollow tubular element is at least 6 mm.

The length of the downstream hollow tubular element is preferably less than 20 mm. More preferably, the downstream hollow tubular element has a length of less than 15 mm. More preferably, the downstream hollow tubular element has a length of less than 12 mm. More preferably, the downstream hollow tubular element has a length of less than 10 mm.

For example, the length of the downstream hollow tubular element may be between 3 and 20 millimeters, or between 4 and 20 millimeters, or between 5 and 20 millimeters, or between 6 and 20 millimeters. In other embodiments, the length of the downstream hollow tubular element may be between 3 and 15 millimeters, or between 4 and 15 millimeters, or between 5 and 15 millimeters, or between 6 and 15 millimeters. In other embodiments, the length of the downstream hollow tubular element may be between 3 and 12 millimeters, or between 4 and 12 millimeters, or between 5 and 12 millimeters, or between 6 and 12 millimeters. In other embodiments, the length of the downstream hollow tubular element may be between 3 and 10 millimeters, or between 4 and 10 millimeters, or between 5 and 10 millimeters, or between 6 and 10 millimeters.

Where a downstream hollow tubular element is included in the downstream section, the combined length of the hollow tubular cooling element and the downstream hollow tubular element(s) is preferably at least 20 millimeters. This corresponds to the sum of the length of the hollow tubular cooling element and the length of the downstream hollow tubular element(s), irrespective of the length of any components provided therebetween. More preferably, the combined length is at least 30 millimeters. The combined length may be at least 40 millimeters. More preferably, the combined length is at least 45 millimeters.

The combined length of the hollow tubular cooling element and the downstream hollow tubular element(s) is preferably less than 60 mm. More preferably, the combined length is less than 55 millimeters. More preferably, the combined length is less than 50 millimeters.

For example, the combined length of the hollow tubular cooling element and the downstream hollow tubular element(s) may be between 20 and 60 millimeters, or between 30 and 60 millimeters, or between 40 and 60 millimeters, or between 45 and 60 millimeters. In other embodiments, the combined length may be between 20 millimeters and 55 millimeters, or between 30 millimeters and 55 millimeters, or between 40 millimeters and 55 millimeters, or between 45 millimeters and 55 millimeters. In other embodiments, the combined length may be between 20 millimeters and 50 millimeters, or between 30 millimeters and 50 millimeters, or between 40 millimeters and 50 millimeters, or between 45 millimeters and 50 millimeters.

By providing a combined length in the above-mentioned range, the overall length of the hollow tubular element in the downstream section is relatively long, with the benefits as set forth above in relation to the length of the hollow tubular cooling element.

The lumen or cavity of the downstream hollow tubular element may have any cross-sectional shape. The lumen of the downstream hollow tubular element may have a circular cross-sectional shape.

The downstream hollow tubular element may comprise a paper-based material. The downstream hollow tubular element may comprise at least one paper layer. The paper may be very hard paper. The paper may be a curled paper, such as curled heat resistant paper or curled parchment paper.

The downstream hollow tubular element may comprise paperboard. The downstream hollow tubular element may be a cardboard tube.

The downstream hollow tubular element may be a paper tube. The downstream hollow tubular element may be a tube formed from helically wound paper. The downstream hollow tubular element may be formed from a plurality of paper layers. The paper may have a basis weight of at least 50 grams per square meter, at least 60 grams per square meter, at least 70 grams per square meter, or at least 90 grams per square meter.

The downstream hollow tubular element may comprise a polymeric material. For example, the downstream hollow tubular element may comprise a polymer membrane. The polymer film may comprise a cellulosic film. The downstream hollow tubular member may comprise a low density polyethylene (HDPE) or Polyhydroxyalkanoate (PHA) fiber. Preferably, the downstream hollow tubular element comprises cellulose acetate tow. For example, in a preferred embodiment, the downstream hollow tubular element comprises a hollow acetate tube.

Where the downstream hollow tubular element comprises cellulose acetate tow, the cellulose acetate tow may have a denier per filament of between 2 and 4 and a total denier of between 25 and 40.

In the case that the downstream section further comprises an additional downstream hollow tubular element, the additional downstream hollow tubular element may be formed of the same material as the downstream hollow tubular element or a different material, as described above.

In certain preferred embodiments, the downstream section may include a ventilation zone at a location on the downstream hollow tubular element. In one example, this vent zone may be provided at a location on the downstream hollow tubular element rather than at a location on the hollow tubular cooling element. In another example, a ventilation zone at a location on the downstream hollow tubular element may be provided in addition to a ventilation zone at a location on the hollow tubular cooling element.

The venting zone at a location along the downstream hollow tubular element may comprise a plurality of perforations through the peripheral wall of the downstream hollow tubular element. Preferably, the ventilation zone at a location along the downstream hollow tubular element comprises at least one row of circumferential perforations. In some embodiments, the vented zone may include two circumferential rows of perforations. For example, perforations may be formed on the production line during manufacture of the aerosol-generating article. Preferably, each row of circumferential perforations comprises 8 to 30 perforations.

The distance between the ventilation zone and the upstream end of the downstream hollow tubular element may be at least 1 mm. The distance between the ventilation zone and the upstream end of the downstream hollow tubular element may be at least 2 mm. Preferably, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is at least 3 mm.

The distance between the ventilation zone and the upstream end of the downstream hollow tubular element is preferably less than or equal to 10 mm. More preferably, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is less than or equal to 7 mm. Even more preferably, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is less than or equal to 5mm.

In some embodiments, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is from 1 mm to 10 mm, preferably from 1 mm to 7 mm, more preferably from 1 mm to 5 mm. In further embodiments, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is from 2 to 10 mm, preferably from 2 to 7 mm, more preferably from 2 to 5 mm. In other embodiments, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is 3 to 10 mm, preferably 3 to 7 mm, more preferably 3 to 5 mm.

Positioning the ventilation zone at a distance from the upstream end of the downstream hollow tubular element within the above-mentioned range has the advantage of generally ensuring that, during use, when the aerosol-generating article is inserted into the heating device, the ventilation zone is just outside the heating device, while reducing the risk of the ventilation zone being inadvertently obscured by the lips or hands of the user.

The downstream section may optionally further comprise additional cooling elements defining a plurality of longitudinally extending channels in order to make a large surface area available for heat exchange. In other words, one such additional cooling element is adapted to essentially act as a heat exchanger. The plurality of longitudinally extending channels may be defined by sheet material that has been pleated, gathered or folded to form the channels. The plurality of longitudinally extending channels may be defined by a single sheet that has been pleated, gathered, and folded to form the plurality of channels. The sheet may have been curled prior to pleating, gathering or folding. Alternatively, the plurality of longitudinally extending channels may be defined by a plurality of sheets that have been curled, pleated, gathered, and folded to form the plurality of channels. In some embodiments, the plurality of longitudinally extending channels may be defined by a plurality of sheets that have been curled, pleated, gathered or folded together, i.e., by two or more sheets that have been brought into an overlying arrangement and then curled, pleated, gathered or folded into one.

As used herein, the term "curled" means that the sheet has a plurality of substantially parallel ridges or corrugations. Preferably, when the aerosol-generating article has been assembled, the substantially parallel ridges or corrugations extend in a longitudinal direction relative to the strip. As used herein, the terms "gathering", "pleating" or "folding" mean that a sheet of material is wound, folded or otherwise compressed or contracted substantially transverse to the cylindrical axis of the strip. The sheet may be curled prior to being gathered, pleated or folded. The sheet may be gathered, pleated, or folded without prior advance crimping.

One such additional cooling element may have a total surface area of between about 300 square millimeters per millimeter of length and about 1000 square millimeters per millimeter of length.

The additional cooling element preferably provides a low resistance to the passage of air through the additional cooling element. Preferably, the additional cooling element does not substantially affect the resistance to draw of the aerosol-generating article. In order to achieve this, it is preferred that the porosity in the longitudinal direction is greater than 50% and that the air flow path through the additional cooling element is relatively unconstrained. The longitudinal porosity of the additional cooling element may be defined by the ratio of the cross-sectional area of the material forming the additional cooling element to the internal cross-sectional area of the aerosol-generating article at the portion containing the additional cooling element.

The additional cooling element preferably comprises a sheet material selected from the group consisting of metal foil, polymer sheet and substantially non-porous paper or paperboard. In some embodiments, the aerosol-cooling element may comprise a sheet material selected from the group consisting of: polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polylactic acid (PLA), cellulose Acetate (CA) and aluminum foil. In a particularly preferred embodiment, the additional cooling element comprises a sheet of PLA.

The aerosol-generating article may have an overall length of 45 mm to 100 mm.

Preferably, the overall length of the aerosol-generating article according to the invention is at least 50 mm. More preferably, the overall length of the aerosol-generating article according to the invention is at least 60 mm. Even more preferably, the overall length of the aerosol-generating article according to the invention is at least 70 mm.

The overall length of the aerosol-generating article according to the invention is preferably less than or equal to 90 mm. More preferably, the overall length of the aerosol-generating article according to the invention is preferably less than or equal to 85 mm. Even more preferably, the overall length of the aerosol-generating article according to the invention is preferably less than or equal to 80mm.

In some embodiments, the overall length of the aerosol-generating article is preferably from 50 to 90 mm, more preferably from 60 to 90 mm, even more preferably from 70 to 90 mm. In other embodiments, the overall length of the aerosol-generating article is preferably from 50 to 85 mm, more preferably from 60 to 85 mm, even more preferably from 70 to 85 mm. In further embodiments, the overall length of the aerosol-generating article is preferably from 50 to 80mm, more preferably from 60 to 80mm, even more preferably from 70 to 80 mm. In an exemplary embodiment, the overall length of the aerosol-generating article is 75 millimeters.

The aerosol-generating article preferably has an outer diameter of at least 5mm along the entire length of the article. In the case of a diameter that varies along the length of the aerosol-generating article, the outer diameter is preferably at least 5mm at all locations along the length of the article.

Preferably, the aerosol-generating article has an outer diameter of at least 5.5 mm along the entire length of the article. More preferably, the aerosol-generating article has an outer diameter of at least 6 mm along the entire length of the article.

Preferably, the aerosol-generating article has a maximum outer diameter of less than 10 mm. This means that if the diameter of the aerosol-generating article varies along the length of the article, the diameter at all locations along the length is less than 10 mm. More preferably, the aerosol-generating article has a maximum outer diameter of less than 9 mm. Even more preferably, the aerosol-generating article has a maximum outer diameter of less than 8 mm. Even more preferably, the aerosol-generating article has a maximum outer diameter of less than 7 mm.

In some embodiments, the aerosol-generating article has an outer diameter of from 5mm to 10 mm, preferably from 5.5 mm to 10 mm, more preferably from 6 mm to 10 mm. In other embodiments, the aerosol-generating article has an outer diameter of from 5mm to 9 mm, preferably from 5.5 mm to 9 mm, more preferably from 6 mm to 9 mm. In further embodiments, the aerosol-generating article has an outer diameter of from 5mm to 8 mm, preferably from 5.5 mm to 8 mm, more preferably from 6 mm to 8 mm. In further embodiments, the aerosol-generating article has an outer diameter of from 5mm to 7 mm, preferably from 5.5 mm to 7 mm, more preferably from 6 mm to 7 mm.

The outer diameter of the aerosol-generating article may be substantially constant over the entire length of the article. Alternatively, different portions of the aerosol-generating article may have different outer diameters.

In a particularly preferred embodiment, one or more of the components of the aerosol-generating article are individually defined by their own wrapper.

In an embodiment, the strip of aerosol-generating substrate and the downstream filter segment are packaged separately. The upstream element, the strip of aerosol-generating substrate and the hollow tubular element are then combined with the outer wrapper. They are then combined with downstream filter segments with their own wrapper by means of tipping paper.

Preferably, at least one component of the aerosol-generating article is packaged in a hydrophobic wrapper.

The term "hydrophobic" means that the surface exhibits water-repellent properties. One useful method of determining this is to measure the water contact angle. The "water contact angle" is the angle through a liquid as conventionally measured when the liquid/vapor interface encounters a solid surface. It quantifies the wettability of a solid surface by a liquid via the young's equation. Hydrophobicity or water contact angle can be determined by using TAPPI T558 test method, and the results are presented as interface contact angles and reported in degrees, and can range from near zero degrees to near 180 degrees.

In a preferred embodiment, the hydrophobic wrapper is a wrapper comprising a paper layer having a water contact angle of about 30 degrees or greater, and preferably about 35 degrees or greater, or about 40 degrees or greater, or about 45 degrees or greater.

For example, the paper layer may comprise PVOH (polyvinyl alcohol) or silicon. PVOH may be applied as a surface coating to the paper layer, or the paper layer may include a surface treatment comprising PVOH or silicon.

In a particularly preferred embodiment, an aerosol-generating article according to the invention comprises an upstream element, a strip of aerosol-generating substrate positioned immediately downstream of the upstream element, a hollow tubular cooling element positioned immediately downstream of the strip of aerosol-generating substrate, a downstream filter segment positioned immediately downstream of the hollow tubular cooling element, a downstream hollow tubular element positioned immediately downstream of the downstream filter segment, and one or more overwraps combining the above components together. The upstream element defines an upstream section of the aerosol-generating article. The hollow tubular cooling element, the downstream filter section and the downstream hollow tubular element form a downstream section of the aerosol-generating article.

The strip of aerosol-generating substrate may abut the upstream element. The hollow tubular cooling element may abut a strip of aerosol-generating substrate. The downstream filter segment may abut the hollow tubular cooling element. The downstream hollow tubular element may abut the downstream filter segment. Preferably, the hollow tubular cooling element is adjacent to a strip of aerosol-generating substrate, the downstream filter segment is adjacent to the hollow tubular cooling element, and the downstream hollow tubular element is adjacent to the downstream filter segment.

The present disclosure also relates to an aerosol-generating system comprising an aerosol-generating device having a distal end and a mouth end. The aerosol-generating device may comprise a body. The body or housing of the aerosol-generating device may define a device cavity for removably receiving an aerosol-generating article at the mouth end of the device. The aerosol-generating device may comprise a heating element or heater for heating the aerosol-generating substrate when the aerosol-generating article is received within the device cavity.

The device cavity may be referred to as a heating chamber of the aerosol-generating device. The device lumen may extend between the distal end and the oral end or the proximal end. The distal end of the device lumen may be a closed end and the oral or proximal end of the device lumen may be an open end. The aerosol-generating article may be inserted into the device cavity or the heating chamber via the open end of the device cavity. The device cavity may be cylindrical so as to conform to the same shape of the aerosol-generating article.

The expression "received within" may refer to the fact that a component or element is received entirely or partially within another component or element. For example, the expression "the aerosol-generating article is received within the device cavity" means that the aerosol-generating article is received completely or partially within the device cavity of the aerosol-generating article. The aerosol-generating article may abut a distal end of the device cavity when the aerosol-generating article is received within the device cavity. When the aerosol-generating article is received within the device cavity, the aerosol-generating article may be substantially proximal to the distal end of the device cavity. The distal end of the device lumen may be defined by an end wall.

The length of the device lumen may be between 10 mm and 50 mm. The length of the device lumen may be between 20mm and 40 mm. The length of the device lumen may be between 25mm and 30 mm.

The length of the device cavity (or heating chamber) may be equal to or greater than the length of the strip of aerosol-generating substrate. The length of the device lumen may be equal to or greater than the combined length of the upstream section or element and the strip of aerosol-generating substrate. Preferably, the length of the device cavity is such that when the aerosol-generating article is received within the aerosol-generating device, at least 75% of the length of the strip of aerosol-generating substrate is inserted or received within the device cavity. More preferably, the length of the device cavity is such that when the aerosol-generating article is received within the aerosol-generating device, at least 80% of the length of the strip of aerosol-generating substrate is inserted or received within the device cavity. More preferably, the length of the device cavity is such that when the aerosol-generating article is received within the aerosol-generating device, at least 90% of the length of the strip of aerosol-generating substrate is inserted or received within the device cavity. This maximises the length of the strip of aerosol-generating substrate along which the aerosol-generating substrate may be heated during use, thereby optimising the generation of aerosol from the aerosol-generating substrate and reducing tobacco wastage.

The length of the device cavity may be such that the downstream section or a portion thereof is configured to protrude from the device cavity when the aerosol-generating article is received within the device cavity. The length of the device cavity may be such that a portion of the downstream section (e.g., the hollow tubular cooling element or the downstream filter segment) is configured to protrude from the device cavity when the aerosol-generating article is received within the device cavity. The length of the device cavity may be such that a portion of the downstream section (e.g., the hollow tubular cooling element or the downstream filter segment) is configured to be received within the device cavity when the aerosol-generating article is received within the device cavity.

When the aerosol-generating article is received within the device, at least 25% of the length of the downstream section may be inserted or received within the device cavity. When the aerosol-generating article is received within the device, at least 30% of the length of the downstream section may be inserted or received within the device cavity.

When the aerosol-generating article is received within the device, at least 30% of the length of the hollow tubular element may be inserted or received within the device lumen. At least 40% of the length of the hollow tubular element may be inserted or received within the device lumen when the aerosol-generating article is received within the device. When the aerosol-generating article is received within the device, at least 50% of the length of the hollow tubular element may be inserted or received within the device lumen. Hollow tubular elements of various lengths are described in more detail within this disclosure.

Optimizing the amount or length of the article inserted into the aerosol-generating device may enhance the resistance of the article to accidental drop during use. In particular, during heating of the aerosol-generating substrate, the substrate may shrink such that its outer diameter may decrease, thereby reducing the extent to which the insertion portion of the article inserted into the device may frictionally engage the device cavity. The length of the inserted portion of the article or the portion of the article configured to be received within the device cavity may be the same as the device cavity.

The length of the device lumen may be between 15 mm and 80 mm. Preferably, the length of the device lumen is between 20 mm and 70 mm. More preferably, the length of the device lumen is between 25 mm and 60 mm. More preferably, the length of the device is between 25 and 50 mm.

The length of the device lumen may be between 25 mm and 29 mm. Preferably, the length of the device lumen is between 25 mm and 29 mm. More preferably, the length of the device lumen is between 26 and 29 millimeters. Even more preferably, the length of the device lumen is 27 mm or 28 mm.

The diameter of the device lumen may be between 4 mm and 10 mm. The diameter of the device lumen may be between 5mm and 9 mm. The diameter of the device lumen may be between 6 mm and 8 mm. The diameter of the device lumen may be between 6 mm and 7 mm.

The diameter of the device cavity may be substantially equal to or greater than the diameter of the aerosol-generating article. The diameter of the device cavity may be the same as the diameter of the aerosol-generating article in order to establish a close fit with the aerosol-generating article.

The device cavity may be configured to establish a close fit with an aerosol-generating article received within the device cavity. The tight fit may refer to a snug fit. The aerosol-generating device may comprise a peripheral wall. The peripheral wall may define a device cavity or heating chamber. The peripheral wall defining the device cavity may be configured to engage with the aerosol-generating article received within the device cavity in a close-fitting manner such that there is substantially no gap or empty space between the peripheral wall defining the device cavity and the aerosol-generating article when the aerosol-generating article is received within the device.

Such a tight fit may establish an airtight fit or configuration between the device cavity and the aerosol-generating article received therein.

With such an airtight configuration, there will be substantially no gap or empty space for air to flow through between the peripheral wall defining the device cavity and the aerosol-generating article.

A close fit with the aerosol-generating article may be established along the entire length of the device cavity or along a portion of the length of the device cavity.

The aerosol-generating device may comprise an airflow channel extending between a channel inlet and a channel outlet. The airflow channel may be configured to establish fluid communication between an interior of the device cavity and an exterior of the aerosol-generating device. An airflow passage of the aerosol-generating device may be defined within the housing of the aerosol-generating device to enable fluid communication between the interior of the device cavity and the exterior of the aerosol-generating device. When the aerosol-generating article is received within the device cavity, the airflow channel may be configured to provide an airflow into the article so as to deliver the generated aerosol to a user inhaling from the mouth end of the article.

The airflow channel of the aerosol-generating device may be defined within or by an outer peripheral wall of the housing of the aerosol-generating device. In other words, the airflow channel of the aerosol-generating device may be defined within the thickness of the peripheral wall or by the inner surface of the peripheral wall, or a combination of both. The airflow channel may be defined in part by an inner surface of the peripheral wall and may be defined in part within a thickness of the peripheral wall. The inner surface of the peripheral wall defines the peripheral boundary of the device cavity.

The airflow channel of the aerosol-generating device may extend from an inlet at the mouth end or proximal end of the aerosol-generating device to an outlet remote from the mouth end of the device. The airflow channel may extend in a direction parallel to the longitudinal axis of the aerosol-generating device.

The heater may be any suitable type of heater. Preferably, in the present invention, the heater is an external heater.

Preferably, the heater may externally heat the aerosol-generating article when the aerosol-generating article is received within the aerosol-generating device. Such an external heater may define the aerosol-generating article when the aerosol-generating article is inserted into or received within the aerosol-generating device.

In some embodiments, the heater is arranged to heat an outer surface of the aerosol-generating substrate. In some embodiments, the heater is arranged to be inserted into the aerosol-generating substrate when the aerosol-generating substrate is received within the cavity. The heater may be positioned within the device cavity or heating chamber.

The heater may comprise at least one heating element. The at least one heating element may be any suitable type of heating element. In some embodiments, the device comprises only one heating element. In some embodiments, the device comprises a plurality of heating elements. The heater may comprise at least one resistive heating element. Preferably, the heater comprises a plurality of resistive heating elements. Preferably, the resistive heating elements are electrically connected in a parallel arrangement. Advantageously, providing a plurality of resistive heating elements electrically connected in a parallel arrangement may facilitate delivering desired power to the heater while reducing or minimizing the voltage required to provide the desired power. Advantageously, reducing or minimizing the voltage required to operate the heater may be advantageous in reducing or minimizing the physical size of the power supply.

Suitable materials for forming the at least one resistive heating element include, but are not limited to: semiconductors such as doped ceramics, electrically "conductive" ceramics (e.g., molybdenum disilicide), carbon, graphite, metals, metal alloys, and composites made from ceramic materials and metal materials. Such composite materials may include doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, and platinum group metals. Examples of suitable metal alloys include stainless steel, nickel-containing alloys, cobalt-containing alloys, chromium-containing alloys, aluminum-containing alloys, titanium-containing alloys, zirconium-containing alloys, hafnium-containing alloys, niobium-containing alloys, molybdenum-containing alloys, tantalum-containing alloys, tungsten-containing alloys, tin-containing alloys, gallium-containing alloys, manganese-containing alloys, and iron-containing alloys, and superalloys based on nickel, iron, cobalt, stainless steel, timetal ^®, and iron-manganese-aluminum-based alloys.

In some embodiments, the at least one resistive heating element comprises one or more stamped portions of resistive material (such as stainless steel). Alternatively, the at least one resistive heating element may comprise a heating wire or filament, such as a Ni-Cr (nickel-chromium), platinum, tungsten or alloy wire.

In some embodiments, the at least one heating element comprises an electrically insulating substrate, wherein the at least one resistive heating element is disposed on the electrically insulating substrate.

The electrically insulating substrate may comprise any suitable material. For example, the electrically insulating substrate may include one or more of the following: paper, glass, ceramic, anodized metal, coated metal, and polyimide. The ceramic may include mica, alumina (Al ₂O₃) or zirconia (ZrO ₂). Preferably, the electrically insulating substrate has a thermal conductivity of less than or equal to about 40 watts/meter-kelvin, preferably less than or equal to about 20 watts/meter-kelvin, and desirably less than or equal to about 2 watts/meter-kelvin.

The heater may include a heating element comprising a rigid electrically insulating substrate having one or more electrically conductive tracks or wires disposed on a surface thereof. The electrically insulating substrate may be sized and shaped to allow its direct insertion into the aerosol-generating substrate. If the electrically insulating substrate is not sufficiently rigid, the heating element may comprise further stiffening means. An electrical current may be passed through one or more conductive tracks to heat the heating element and aerosol-generating substrate.

In some embodiments, the heater comprises an induction heating device. The induction heating apparatus may include an inductor coil and a power source configured to provide a high frequency oscillating current to the inductor coil. As used herein, high frequency oscillating current means an oscillating current having a frequency between about 500 kHz and about 30 MHz. Advantageously, the heater may comprise a DC/AC inverter for converting DC current supplied by the DC power supply into alternating current. The inductor coil may be arranged to generate a high frequency oscillating electromagnetic field upon receiving a high frequency oscillating current from a power supply. The inductor coil may be arranged to generate a high frequency oscillating electromagnetic field in the device cavity. In some embodiments, the inductor coil may substantially define a device cavity. The inductor coil may extend at least partially along the length of the device lumen.

The heater may comprise an induction heating element. The induction heating element may be a susceptor element. As used herein, the term "susceptor element" refers to an element comprising a material capable of converting electromagnetic energy into heat. When the susceptor element is in an alternating electromagnetic field, the susceptor is heated. Heating of the susceptor element may be a result of at least one of hysteresis losses and eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material.

The susceptor element may be arranged such that when the aerosol-generating article is received in the cavity of the aerosol-generating device, the oscillating electromagnetic field generated by the inductor coil induces an electric current in the susceptor element, thereby causing the susceptor element to heat up. In these embodiments, the aerosol-generating device is preferably capable of generating a fluctuating electromagnetic field having a magnetic field strength (H field strength) of between 1 kiloamp per meter and 5 kiloamps per meter (kA m), preferably between 2 kA/m and 3 kA/m, for example about 2.5 kA/m. Preferably, the electrically operated aerosol-generating device is capable of generating a fluctuating electromagnetic field having a frequency of between 1 MHz and 30 MHz, such as between 1 MHz and 10 MHz, such as between 5 MHz and 7 MHz.

In these embodiments, the susceptor element is preferably positioned in contact with the aerosol-generating substrate. In some embodiments, the susceptor element is located in an aerosol-generating device. In these embodiments, the susceptor element may be located in the cavity. The aerosol-generating device may comprise only one susceptor element. The aerosol-generating device may comprise a plurality of susceptor elements. In some embodiments, the susceptor element is preferably arranged to heat the outer surface of the aerosol-generating substrate.

The susceptor element may comprise any suitable material. The susceptor element may be formed of any material capable of being inductively heated to a temperature sufficient to release volatile compounds from the aerosol-generating substrate. Suitable materials for the elongate susceptor element include graphite, molybdenum, silicon carbide, stainless steel, niobium, aluminium, nickel-containing compounds, titanium and metal material composites. Some susceptor elements include metal or carbon. Advantageously, the susceptor element may comprise or consist of a ferromagnetic material, such as ferrite iron, ferromagnetic alloys (e.g. ferromagnetic steel or stainless steel), ferromagnetic particles and ferrite. Suitable susceptor elements may be or include aluminum. The susceptor element preferably comprises about more than 5%, preferably more than 20%, more preferably more than 50% or more than 90% of ferromagnetic or paramagnetic material. Some elongated susceptor elements may be heated to a temperature exceeding 250 degrees celsius.

The susceptor element may comprise a non-metallic core on which a metal layer is provided. For example, the susceptor element may comprise a metal track formed on an outer surface of a ceramic core or substrate.

In some embodiments, the aerosol-generating device may comprise at least one resistive heating element and at least one inductive heating element. In some embodiments, the aerosol-generating device may comprise a combination of resistive and inductive heating elements.

During use, the heater is controllable to operate within a defined operating temperature range below a maximum operating temperature. An operating temperature range between about 150 degrees celsius and about 300 degrees celsius in the heating chamber (or device cavity) is preferred. The operating temperature range of the heater may be between about 150 degrees celsius and about 250 degrees celsius.

Preferably, the heater may operate at a temperature range between about 150 degrees celsius and about 200 degrees celsius. More preferably, the heater may operate at a temperature range between about 180 degrees celsius and about 200 degrees celsius. In particular, it has been found that optimal and consistent aerosol delivery can be achieved when using an aerosol-generating device having an external heater with an operating temperature range between about 180 degrees celsius and about 200 degrees celsius, wherein the aerosol-generating article has a relatively low RTD (e.g., a downstream segment RTD of less than 15 millimeters H ₂ O), as described in the present disclosure.

In embodiments in which the aerosol-generating article comprises a ventilation zone at a location along the downstream section or hollow tubular element, the ventilation zone may be arranged to be exposed when the aerosol-generating article is received within the device cavity. Thus, the length of the device cavity or heating chamber may be less than the distance of the upstream end of the aerosol-generating article to the ventilation zone located along the downstream section. In other words, the distance between the ventilation zone and the upstream end of the upstream element may be greater than the length of the heating chamber when the aerosol-generating article is received within the aerosol-generating device.

The vented zone may be positioned at least 0.5 millimeters away (in the downstream direction of the article) from the mouth end (or mouth end surface) of the device cavity or the device itself when the article is received within the device cavity. The vented zone may be positioned at least 1 millimeter away (in the downstream direction of the article) from the mouth end (or mouth end face) of the device cavity or the device itself when the article is received within the device cavity. The vented zone may be positioned at least 2 millimeters away (in the downstream direction of the article) from the mouth end (or mouth end face) of the device cavity or the device itself when the article is received within the device cavity.

Preferably, the ratio between the distance between the ventilation zone and the upstream end of the upstream element and the length of the heating chamber is from 1.03 to 1.13.

This positioning of the ventilation zone ensures that the ventilation zone is not blocked within the device cavity itself, while also minimizing the risk of blockage by the lips or hands of the user, as the ventilation zone is located as reasonably as possible at the most upstream location from the downstream end of the article, without being blocked within the device cavity.

The aerosol-generating device may comprise a power supply. The power source may be a DC power source. In some embodiments, the power source is a battery. The power source may be a nickel metal hydride battery, a nickel cadmium battery or a lithium-based battery, such as a lithium cobalt battery, a lithium iron phosphate battery or a lithium polymer battery. However, in some embodiments, the power source may be another form of charge storage device, such as a capacitor. The power source may need to be recharged and may have a capacity that allows for storing sufficient energy for one or more user operations (e.g., one or more aerosol-generating experiences). For example, the power source may have sufficient capacity to allow continuous heating of the aerosol-generating substrate for a period of about six minutes, corresponding to typical times spent drawing a conventional cigarette, or for times that are multiples of six minutes. In another example, the power source may have sufficient capacity to allow a predetermined number of puffs or discrete activations of the heater.

A non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

EX1. An aerosol-generating article comprising: strips of aerosol-generating substrate.

EX2. The aerosol-generating article according to example EX1, wherein the strip of aerosol-generating substrate has a length of at least 17 millimeters.

EX3. An aerosol-generating article according to any preceding example, wherein the rod of aerosol-generating substrate comprises tobacco material.

EX4. The aerosol-generating article according to example EX3, wherein the tobacco material has a density of less than 350 mg/cc.

EX5 the aerosol-generating article according to example EX4, wherein the tobacco material has a density of less than 300 mg/cc.

EX6 the aerosol-generating article according to example EX3, EX4 or EX5, wherein the tobacco material has a density of at least 100 mg/cc.

EX7. The aerosol-generating article according to example EX3, wherein the tobacco material has a density of between 150 mg/cc and 500 mg/cc.

EX8 the aerosol-generating article according to example EX7, wherein the tobacco material has a density of between 200 mg/cc and 400 mg/cc.

EX9. An aerosol-generating article according to any preceding example, comprising a downstream section disposed downstream of a rod of the aerosol-generating substrate.

EX10. The aerosol-generating article according to example EX9, wherein the downstream section comprises a hollow tubular element adjoining a downstream end of the strip of aerosol-generating substrate.

EX11. The aerosol-generating article according to example EX10, wherein the hollow tubular element has a length of at least 40 millimeters.

EX12. The aerosol-generating article according to example EX9, wherein the downstream section comprises a downstream filter segment.

EX13. The aerosol-generating article of example EX12, wherein the downstream section comprises a ventilation zone at a location downstream of the downstream filter segment.

EX14. Aerosol-generating article according to example EX12 or EX13, wherein the downstream filter segment is a solid rod.

EX15. An aerosol-generating article according to any of examples EX12 to EX14, comprising a downstream hollow tubular element located downstream of the downstream filter segment.

EX16. The aerosol-generating article of example EX15, wherein the downstream hollow tubular element abuts the downstream end of the downstream filter segment.

EX17 the aerosol-generating article of example EX15 or EX16, wherein the vented zone is at a location along the downstream hollow tubular element.

EX18 the aerosol-generating article according to example EX17, wherein the ventilation zone is located at a position towards the upstream end of the downstream hollow tubular element.

EX19 the aerosol-generating article according to any of examples EX12 to EX18, wherein the downstream section comprises a hollow tubular cooling element, and wherein the downstream filter segment abuts a downstream end of the hollow tubular cooling element.

EX20 the aerosol-generating article according to any one of examples EX12 to EX19, wherein the downstream filter segment has a length of at least 5 millimeters.

EX21 the aerosol-generating article according to any of examples EX12 to EX20, wherein the downstream filter segment has a length of less than or equal to 20 millimeters.

EX22 the aerosol-generating article according to any of examples EX12 or EX21, wherein the downstream filter segment has a length of between 5 millimeters and 20 millimeters.

EX23. The aerosol-generating article according to example EX9, wherein the downstream section extends to a downstream end of the aerosol-generating article.

EX24. Aerosol-generating article according to example EX9 or EX23, wherein the downstream section comprises a hollow tubular cooling element.

EX25 the aerosol-generating article according to example EX24, wherein the hollow tubular cooling element has a length of at least 20 millimeters.

EX26. The aerosol-generating article according to example EX25, wherein the hollow tubular cooling element has a length of at least 25 millimeters.

EX27 the aerosol-generating article according to any one of examples EX24 to EX26, wherein the hollow tubular cooling element has a length of less than or equal to 50 millimeters.

EX28. The aerosol-generating article according to example EX27, wherein the hollow tubular cooling element has a length of between 20 millimeters and 50 millimeters.

EX29 the aerosol-generating article according to any of examples EX9 or EX23 to EX26, wherein the downstream section has a length of at least 45 millimeters.

EX30. An aerosol-generating article according to any preceding example, wherein the aerosol-generating article has a maximum outer diameter of less than 8 millimeters.

EX31 the aerosol-generating article according to example EX30, wherein the aerosol-generating article has a maximum outer diameter of between 5 millimeters and 8 millimeters.

EX32. The aerosol-generating article according to example EX30 or EX31, wherein the aerosol-generating article has a maximum outer diameter of less than or equal to 7 millimeters.

EX33. The aerosol-generating article according to example EX32, wherein the aerosol-generating article has a maximum outer diameter of between 5.5 millimeters and 7 millimeters.

EX34. The aerosol-generating article according to example EX9, wherein the ratio of the length of the downstream section to the length of the strip of aerosol-generating substrate is at least 1.5.

EX35 the aerosol-generating article according to example EX9, wherein the ratio of the length of the downstream section to the total length of the aerosol-generating article is at least 0.6.

EX36 an aerosol-generating article according to any preceding example, wherein the aerosol-generating article has an overall length of at least 50 millimeters.

EX37 an aerosol-generating article according to any preceding example, wherein the strips of aerosol-generating substrate have a length of less than or equal to 40 millimeters.

EX38 the aerosol-generating article according to example EX37, wherein the strips of aerosol-generating substrate have a length of less than or equal to 36 millimeters.

EX39 an aerosol-generating article according to any preceding example, wherein the strips of aerosol-generating substrate have a length of less than or equal to 30 millimeters.

EX40. An aerosol-generating article according to any preceding example, wherein the strips of aerosol-generating substrate have a length of less than or equal to 25 millimeters.

EX41 an aerosol-generating article according to any preceding example, wherein the strips of aerosol-generating substrate have a length of less than or equal to 20 millimeters.

EX42. An aerosol-generating article according to any preceding example, wherein the ratio of the length of the strip of aerosol-generating substrate to the total length of the aerosol-generating article is less than or equal to 0.4.

EX43. An aerosol-generating article according to any preceding example, wherein the strip of aerosol-generating substrate has a length of at least 17 mm.

EX44. An aerosol-generating article according to any preceding example, wherein the strip of aerosol-generating substrate has a length of at least 20 mm.

EX45 an aerosol-generating article according to any preceding example, wherein the strip of aerosol-generating substrate has a length of at least 25 mm.

EX46. An aerosol-generating article according to any preceding example, wherein the strip of aerosol-generating substrate has a length of at least 29 mm.

EX47. An aerosol-generating article according to any preceding example, wherein the strip of aerosol-generating substrate has a length of between 29 mm and 36 mm.

EX48 an aerosol-generating article according to any preceding example, comprising an upstream element.

EX49 the aerosol-generating article according to example EX48, wherein the upstream element is disposed upstream of the strip of aerosol-generating substrate.

EX50. An aerosol-generating article according to example EX48 or EX49, wherein the upstream element is disposed adjacent an upstream end of the rod of aerosol-generating substrate.

EX51 the aerosol-generating article according to any of examples EX48 to EX50, wherein the upstream element has a length of between 2mm and 8 mm.

EX52. The aerosol-generating article according to any of examples EX48 to EX51, wherein the upstream element has a length of between 2mm and 6mm.

EX53 the aerosol-generating article according to any of examples EX48 to EX52, wherein the upstream element has a length of between 4 mm and 6mm.

EX54 an aerosol-generating article according to any of examples EX48 to EX53, wherein the upstream element comprises a hollow support section having a central longitudinal cavity extending therethrough.

EX55. The aerosol-generating article according to example EX54, wherein the hollow tubular support element has a wall thickness of less than 1 millimeter.

EX56. The aerosol-generating article according to one of examples EX48 to EX55, wherein the upstream element has a Resistance To Draw (RTD) of less than or equal to 10 millimeters H ₂ O.

EX57. An aerosol-generating article according to any preceding example, wherein the aerosol-generating article has an overall length of at least 60 millimeters.

EX58 the aerosol-generating article according to example EX57, wherein the aerosol-generating article has an overall length of at least 65 millimeters.

EX59. an aerosol-generating article according to any preceding example, wherein the aerosol-generating article has an overall length of less than or equal to 90 millimeters.

EX60. An aerosol-generating article according to any preceding example, wherein the aerosol-generating article has an overall length of between 65 millimeters and 90 millimeters.

EX61 an aerosol-generating article according to any preceding example, wherein the strip of aerosol-generating substrate comprises one or more aerosol-forming agents.

EX62. The aerosol-generating article according to example EX61, wherein the rod of aerosol-generating substrate has an aerosol-former content of less than or equal to 30 wt% on a dry weight basis.

EX63. The aerosol-generating article according to example EX62, wherein the rod of aerosol-generating substrate has an aerosol-former content of less than or equal to 20 wt% on a dry weight basis.

EX64. The aerosol-generating article according to example EX63, wherein the rod of aerosol-generating substrate has an aerosol-former content of less than or equal to 10 wt% on a dry weight basis.

EX65. The aerosol-generating article according to example EX62, wherein the rod of aerosol-generating substrate has an aerosol-former content of between 10 and 30 wt% on a dry weight basis.

EX66 the aerosol-generating article according to any of examples EX61 to EX65, wherein the one or more aerosol-forming agents comprises one or more of glycerol and propylene glycol.

EX67. An aerosol-generating article according to any preceding example, wherein the ratio of the length of the upstream element to the length of the hollow tubular element of the downstream section is between 0.01 and 0.15.

EX68 the aerosol-generating article according to any one of examples EX3 to EX67, wherein the tobacco material comprises shredded tobacco material.

EX69. An aerosol-generating article according to any preceding example, wherein the ratio of the length of the strip of aerosol-generating substrate to the total length of the aerosol-generating article is at least 0.2, preferably 0.25.

EX70. An aerosol-generating system, the aerosol-generating system comprising:

an aerosol-generating article according to any preceding example; and

An aerosol-generating device comprising a heating chamber for receiving the aerosol-generating article and at least a heating element disposed at or around a periphery of the heating chamber.

Drawings

The invention will be further described hereinafter with reference to the drawings, in which:

fig. 1 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

fig. 2 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

fig. 3a and 3b show schematic side cross-sectional views of an aerosol-generating article according to the present disclosure;

Fig. 4a and 4b show schematic side cross-sectional views of an aerosol-generating article according to the present disclosure;

Fig. 5 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

fig. 6 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

Fig. 7 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

Fig. 8 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

Fig. 9 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

fig. 10 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

fig. 11 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

fig. 12 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

fig. 13 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

fig. 14 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

Fig. 15 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure; and

Fig. 16 shows a schematic side cross-sectional view of an aerosol-generating system comprising an aerosol-generating device and an aerosol-generating article according to the present disclosure.

Detailed Description

The aerosol-generating article shown in all of the figures of the present disclosure comprises a strip 12 of aerosol-generating substrate and a downstream section 14 located downstream of the strip 12 of aerosol-generating substrate. The aerosol-generating article extends from an upstream or distal end 18 to a downstream or mouth end 19. A downstream end or mouth end 19 is defined by the downstream end of the downstream section 14.

Each component of the aerosol-generating article shown in the figures and described in this disclosure may be defined by a corresponding wrapper or may be joined together by one or more wrappers not shown in the figures. Each of the aerosol-generating articles shown in the figures has a maximum outer diameter of about 6.5mm unless otherwise specified.

The strip 12 of aerosol-generating substrate is defined by a wrapper (not shown) and comprises at least one aerosol-generating substrate type described in the present disclosure, such as a cut filler of plants (in particular cut filler of tobacco), homogenized tobacco, a gel formulation or homogenized plant material comprising particles of plants other than tobacco. The strips 12 of aerosol-generating articles shown in all figures have an average tobacco density of about 250 mg/cc.

The downstream section 14 of the aerosol-generating article 10 shown in fig. 1 comprises a hollow tubular cooling element 22, a downstream filter segment 24, and a downstream or mouth-end hollow tubular element 26. The hollow tubular cooling element 22 is located immediately downstream of the strip 12 of aerosol-generating substrate. In other words, the hollow tubular cooling element 22 abuts the downstream end of the strip 12. The downstream filter segment 24 abuts the downstream end of the hollow tubular cooling element 22, and the downstream hollow tubular element 26 abuts the downstream end of the downstream filter segment 24. Thus, the downstream filter segment 24 is located between the hollow tubular cooling element 22 and the downstream hollow tubular element 26. The downstream end 19 of the article 10 is defined by the downstream end of the downstream hollow tubular member 26.

The length of the strip 12 of aerosol-generating substrate is about 40mm.

The hollow tubular cooling element 22 is provided in the form of a hollow cylindrical tube made of cardboard or cellulose acetate. The hollow tubular cooling segment 22 defines an inner cavity that extends from an upstream end of the hollow tubular cooling element 22 all the way to a downstream end of the hollow tubular cooling element 22. The lumen is substantially empty and thus a substantially unrestricted air flow is achieved along the lumen. The hollow tubular cooling element 22 may not substantially affect the overall RTD of the aerosol-generating article 10. The hollow tubular cooling element 22 has a length of about 25mm. The hollow tubular cooling element 22 has a wall thickness of about 250 micrometers (μm).

Downstream filter segment 24 comprises a cylindrical rod of cellulose acetate tow. The length of the downstream filter segment 24 is about 10mm.

The downstream hollow tubular member 26 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The downstream hollow tubular member 26 defines an inner lumen that extends from the upstream end of the downstream hollow tubular member 26 to the downstream end of the downstream hollow tubular member 26. The lumen is substantially empty and thus a substantially unrestricted air flow is achieved along the lumen. The downstream hollow tubular element 26 does not substantially affect the overall RTD of the aerosol-generating article 10. The length of the downstream hollow tubular element 26 is about 6mm. The wall thickness of the downstream hollow tubular element 26 is about 1mm.

The aerosol-generating article 10 comprises a ventilation zone 36 arranged at a position along the hollow tubular cooling element 22. The ventilation zone 36 includes at least one row of circumferential perforations extending through the outer peripheral wall of the hollow tubular cooling element 22 and any wrapper (not shown) defining the hollow tubular cooling element 22. The ventilation zone 36 is disposed about 2 millimeters from the downstream end of the hollow tubular cooling element 22.

The aerosol-generating article 101 shown in fig. 2 is similar to the aerosol-generating article 10 shown in fig. 1 and differs only in the following respects. The strips 12 of aerosol-generating substrate are shorter and the hollow tubular cooling element 22 is longer. The length of the strip 12 of aerosol-generating substrate is about 25mm. The hollow tubular cooling element 22 has a length of about 40mm.

The aerosol-generating article 102 shown in fig. 3a is similar to the aerosol-generating article 101 shown in fig. 2 and differs only in the following respects. The hollow tubular cooling element 22 is shorter and the downstream hollow tubular element 27 is longer. The hollow tubular cooling element 22 has a length of about 25mm. The length of the downstream hollow tubular element 27 is about 20mm. Furthermore, a ventilation zone 36 is provided along the downstream hollow tubular element 27. The ventilation zone 36 is disposed about 2 millimeters from the upstream end of the downstream hollow tubular element 26. The ventilation zone 36 comprises at least one row of circumferential perforations extending through the peripheral wall of the downstream hollow tubular element 27 and any wrapper (not shown) defining the downstream hollow tubular element 27.

The aerosol-generating article 103 shown in fig. 3b is similar to the aerosol-generating article 102 shown in fig. 3a and differs only in the following respects. The downstream hollow tubular element 27 comprises two adjoining hollow tubular segments 271, 272. The first hollow tubular section 271 is located between the downstream filter section 24 and the second first hollow tubular section 272.

In fig. 3b, the first hollow tubular section 271 is provided in the form of a hollow cylindrical tube made of paperboard. The first hollow tubular section 271 defines a lumen that extends from an upstream end of the first hollow tubular section 271 to a downstream end of the first hollow tubular section 271. The lumen is substantially empty and thus a substantially unrestricted air flow is achieved along the lumen. The first hollow tubular section 271 may not substantially affect the overall RTD of the aerosol-generating article 103. The length of the first hollow tubular section 271 is about 10mm. The wall thickness of the first hollow tubular section 271 is about 250 micrometers (μm). The ventilation zone 36 is disposed about 2 millimeters from the upstream end of the first hollow tubular section 271 of the downstream hollow tubular element 27.

In fig. 3b, the second hollow tubular section 272 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The second hollow tubular section 272 defines a lumen that extends from an upstream end of the second hollow tubular section 272 all the way to a downstream end of the second hollow tubular section 272. The lumen is substantially empty and thus a substantially unrestricted air flow is achieved along the lumen. The second hollow tubular section 272 does not substantially affect the overall RTD of the aerosol-generating article 103. The length of the second hollow tubular section 272 is about 10mm. The wall thickness of the second hollow tubular section 272 is about 1mm.

The aerosol-generating article 104, 105 shown in fig. 4a and 4b is similar to the aerosol-generating article 101 shown in fig. 2 and differs only in that the aerosol-generating article 104, 105 further comprises an upstream section 16 located upstream of the strip 12 of aerosol-generating substrate. The distal ends 18 of the articles 104, 105 are defined by the upstream end of the upstream section 16. The upstream section 16 includes upstream elements 341, 342 adjacent the upstream end of the strip 12. The upstream elements 341, 342 are about 5mm in length. In the article 104 shown in fig. 4a, the upstream element 341 is provided in the form of a cylindrical rod of cellulose acetate tow. In the article 105 shown in fig. 4b, the upstream element 342 is provided in the form of a hollow cylindrical tube made of cellulose acetate, having a wall thickness of about 1 mm.

The downstream section 14 of the aerosol-generating article 20 shown in fig. 5 comprises a hollow tubular support element 28, a cooling element 32 and a downstream filter segment 24. The hollow tubular support element 28 is positioned immediately downstream of the strip 12 of aerosol-generating substrate. In other words, the hollow tubular support element 28 abuts the downstream end of the strip 12. The cooling element 32 abuts the downstream end of the hollow tubular support element 28, and the downstream filter segment 24 abuts the downstream end of the cooling element 32. Thus, the cooling element 32 is located between the hollow tubular support element 28 and the downstream filter segment 24. The downstream end 19 of the article 20 is defined by the downstream end of the downstream filter segment 24.

The length of the strip 12 of aerosol-generating substrate is about 25mm.

The hollow tubular support element 28 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The hollow tubular support member 28 defines an interior cavity that extends from an upstream end of the hollow tubular support member 28 to a downstream end of the hollow tubular support member 28. The lumen is substantially empty and thus a substantially unrestricted air flow is achieved along the lumen. The hollow tubular support element 28 may not substantially affect the overall RTD of the aerosol-generating article 20. The hollow tubular support member 28 has a length of about 8mm. The wall thickness of the hollow tubular support element 28 is about 1.5mm.

The cooling element 32 is formed from a thin polylactic acid (PLA) sheet material that has been curled, pleated, gathered or folded to form a channel. The length of the cooling element 32 is about 18mm.

Downstream filter segment 24 comprises a cylindrical rod of cellulose acetate tow. The length of the downstream filter segment 24 is about 7mm.

The maximum outer diameter of the aerosol-generating article 20 is about 7.3mm.

The aerosol-generating article 201 shown in fig. 6 is similar to the aerosol-generating article 20 shown in fig. 5, and differs in that it further comprises a hollow tubular cooling element 22 and the strips 12 of aerosol-generating substrate are shorter. The length of the strip 12 of aerosol-generating substrate is about 12mm. The hollow tubular cooling element 22 is positioned immediately downstream of the cooling element 32 and immediately upstream of the downstream filter segment 24. In other words, the hollow tubular cooling element 22 abuts the cooling element 32 and the downstream filter segment 24.

The hollow tubular cooling element 22 is provided in the form of a hollow cylindrical tube made of cardboard. The hollow tubular cooling segment 22 defines an inner cavity that extends from an upstream end of the hollow tubular cooling element 22 all the way to a downstream end of the hollow tubular cooling element 22. The lumen is substantially empty and thus a substantially unrestricted air flow is achieved along the lumen. The hollow tubular cooling element 22 may not substantially affect the overall RTD of the aerosol-generating article 201. The hollow tubular cooling element 22 has a length of about 25mm. The hollow tubular cooling element 22 has a wall thickness of about 250 micrometers (μm).

The aerosol-generating article 202 shown in fig. 7 is similar to the aerosol-generating article 201 shown in fig. 6 and differs only in that it further comprises a downstream hollow tubular element 27. The downstream hollow tubular element 27 abuts the downstream end of the downstream filter segment 24. Thus, the downstream filter segment 24 is located between the hollow tubular cooling element 22 and the downstream hollow tubular element 27. The downstream end 19 of the article 202 is defined by the downstream end of the downstream hollow tubular element 27.

The downstream hollow tubular element 27 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The downstream hollow tubular member 27 defines an inner lumen that extends from the upstream end of the downstream hollow tubular member 27 to the downstream end of the downstream hollow tubular member 27. The lumen is substantially empty and thus a substantially unrestricted air flow is achieved along the lumen. The downstream hollow tubular element 27 may not substantially affect the overall RTD of the aerosol-generating article 202. The length of the downstream hollow tubular element 27 is about 5mm. The wall thickness of the downstream hollow tubular element 27 is about 1mm.

The aerosol-generating article 30 shown in fig. 8 comprises a strip 12 of aerosol-generating substrate and a downstream section 14 located downstream of the strip 12 of aerosol-generating substrate. Furthermore, the aerosol-generating article 30 comprises an upstream section 16 located upstream of the strip 12 of aerosol-generating substrate. The distal end 18 of the article 30 is defined by the upstream end of the upstream section 16.

The downstream section 14 of the aerosol-generating article 30 shown in fig. 8 comprises a hollow tubular cooling element 22 and a downstream filter segment 24. The hollow tubular cooling element 22 is located immediately downstream of the strip 12 of aerosol-generating substrate. In other words, the hollow tubular cooling element 22 abuts the downstream end of the strip 12. The downstream filter segment 24 abuts the downstream end of the hollow tubular cooling element 22. Thus, the hollow tubular cooling element 22 is located between the strip 12 and the downstream filter segment 24. The downstream end 19 of the article 30 is defined by the downstream end of the downstream filter segment 24.

The length of the strip 12 of aerosol-generating substrate is about 25mm.

The hollow tubular cooling element 22 is provided in the form of a hollow cylindrical tube made of cardboard or cellulose acetate. The hollow tubular cooling segment 22 defines an inner cavity that extends from an upstream end of the hollow tubular cooling element 22 all the way to a downstream end of the hollow tubular cooling element 22. The lumen is substantially empty and thus a substantially unrestricted air flow is achieved along the lumen. The hollow tubular cooling element 22 may not substantially affect the overall RTD of the aerosol-generating article 30. The hollow tubular cooling element 22 has a length of about 21mm. The hollow tubular cooling element 22 has a wall thickness of about 250 micrometers (μm).

The upstream section 16 includes an upstream element 341 that abuts the upstream end of the strip 12. The upstream element 341 is provided in the form of a cylindrical rod of cellulose acetate tow. The length of the upstream element 341 is about 5mm.

The aerosol-generating article 30 comprises a ventilation zone 36 arranged at a position along the hollow tubular cooling element 22. The ventilation zone 36 includes at least one row of circumferential perforations extending through the outer peripheral wall of the hollow tubular cooling element 22 and any wrapper (not shown) defining the hollow tubular cooling element 22. The ventilation zone 36 is disposed about 2 millimeters from the downstream end of the hollow tubular cooling element 22.

The aerosol-generating article 301 shown in fig. 9 is similar to the aerosol-generating article 30 shown in fig. 8 and differs only in that the strips 12 are shorter and the hollow tubular cooling element 22 is longer. In fig. 9, the length of the strip 12 of aerosol-generating substrate is about 12mm and the length of the hollow tubular cooling element 22 is about 45mm.

The aerosol-generating article 302 shown in fig. 10 is similar to the aerosol-generating article 301 shown in fig. 8, and differs in that the strips 12 are shorter and the hollow tubular cooling element 22 is longer, and the article 302 further comprises a downstream hollow tubular element 27. In fig. 10, the length of the strip 12 of aerosol-generating substrate is about 12mm and the length of the hollow tubular cooling element 22 is about 40mm. Thus, the downstream filter segment 24 is located between the hollow tubular cooling element 22 and the downstream hollow tubular element 27. The downstream end 19 of the article 302 is defined by the downstream end of the downstream hollow tubular element 27.

The downstream hollow tubular element 27 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The downstream hollow tubular member 27 defines an inner lumen that extends from the upstream end of the downstream hollow tubular member 27 to the downstream end of the downstream hollow tubular member 27. The lumen is substantially empty and thus a substantially unrestricted air flow is achieved along the lumen. The downstream hollow tubular element 27 may not substantially affect the overall RTD of the aerosol-generating article 302. The length of the downstream hollow tubular element 27 is about 5mm. The wall thickness of the downstream hollow tubular element 27 is about 1mm.

The aerosol-generating article 304 shown in fig. 11 is similar to the aerosol-generating article 302 shown in fig. 10, and differs in that the ventilation zone 36 is instead provided along the downstream hollow tubular element 27. The ventilation zone 36 is disposed about 2 mm from the upstream end of the downstream hollow tubular element 27. The ventilation zone 36 comprises at least one row of circumferential perforations extending through the peripheral wall of the downstream hollow tubular element 27 and any wrapper (not shown) defining the downstream hollow tubular element 27.

The aerosol-generating article 40 shown in fig. 12 comprises a strip 12 of aerosol-generating substrate and a downstream section 14 located downstream of the strip 12 of aerosol-generating substrate. Furthermore, the aerosol-generating article 40 comprises an upstream section 16 located upstream of the strip 12 of aerosol-generating substrate. The distal end 18 of the article is defined by the upstream end of the upstream section 16.

The downstream section 14 of the aerosol-generating article 40 shown in fig. 3 comprises a hollow tubular support element 28, a hollow tubular cooling element 22 and a downstream filter segment 24. The hollow tubular support element 28 is positioned immediately downstream of the strip 12 of aerosol-generating substrate. In other words, the hollow tubular support element 28 abuts the downstream end of the strip 12. The hollow tubular cooling element 22 abuts the downstream end of the hollow tubular support element 28, and the downstream filter segment 24 abuts the downstream end of the hollow tubular cooling element 22. Thus, the hollow tubular cooling element 22 is located between the hollow tubular support element 28 and the downstream filter segment 24. The downstream end 19 of the article 40 is defined by the downstream end of the downstream filter segment 24.

The length of the strip 12 of aerosol-generating substrate is about 20mm.

The hollow tubular support element 28 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The hollow tubular support member 28 defines an interior cavity that extends from an upstream end of the hollow tubular support member 28 to a downstream end of the hollow tubular support member 28. The lumen is substantially empty and thus a substantially unrestricted air flow is achieved along the lumen. The hollow tubular support element 28 may not substantially affect the overall RTD of the aerosol-generating article 40. The hollow tubular support member 28 has a length of about 8mm. The wall thickness of the hollow tubular support element 28 is about 1.5mm.

The hollow tubular cooling element 22 is provided in the form of a hollow cylindrical tube made of cardboard or cellulose acetate. The hollow tubular cooling segment 22 defines an inner cavity that extends from an upstream end of the hollow tubular cooling element 22 all the way to a downstream end of the hollow tubular cooling element 22. The lumen is substantially empty and thus a substantially unrestricted air flow is achieved along the lumen. The hollow tubular cooling element 22 may not substantially affect the overall RTD of the aerosol-generating article 40. The hollow tubular cooling element 22 has a length of about 8mm. The hollow tubular cooling element 22 has a wall thickness of about 250 micrometers (μm).

Downstream filter segment 24 comprises a cylindrical rod of cellulose acetate tow. The length of the downstream filter segment 24 is about 12mm.

The aerosol-generating article 40 comprises a ventilation zone 36 arranged at a position along the hollow tubular cooling element 22. The ventilation zone 36 includes at least one row of circumferential perforations extending through the outer peripheral wall of the hollow tubular cooling element 22 and any wrapper (not shown) defining the hollow tubular cooling element 22. The ventilation zone 36 is disposed about 2 millimeters from the downstream end of the hollow tubular cooling element 22.

The aerosol-generating article 40 comprises an elongate susceptor element 44 located within the strip 12 of aerosol-generating substrate. The susceptor element 44 is arranged substantially longitudinally within the strip 12 so as to be substantially parallel to the longitudinal direction of the strip 12. Since the elongate susceptor element 44 is positioned in thermal contact with the aerosol-generating substrate, the aerosol-generating substrate is heated by the susceptor element 44 when the susceptor element 44 is inductively heated when positioned within the fluctuating electromagnetic field.

As shown in fig. 12, the susceptor element 44 is positioned in a radially central position within the strip and effectively extends along the longitudinal axis of the strip 12. The susceptor element 44 extends from the upstream end of the strip 12 all the way to the downstream end. In practice, the susceptor element 44 has substantially the same length as the strip 12 of aerosol-generating substrate.

The susceptor element 44 is provided in any of the forms described in this disclosure and has a length substantially equal to the length of the strip 12. The upstream section 16 advantageously prevents the susceptor element 44 from being removed. Furthermore, this ensures that the consumer does not accidentally touch the heated susceptor element 44 after use.

The aerosol-generating article 401 shown in fig. 13 is similar to the aerosol-generating article 40 shown in fig. 12 and differs only in that the strips 12 are shorter and the hollow tubular cooling element 22 is longer. In fig. 13, the length of the strip 12 of aerosol-generating substrate is about 12mm and the length of the hollow tubular cooling element 22 is about 25mm.

The aerosol-generating article 402 shown in fig. 14 is similar to the aerosol-generating article 40 shown in fig. 12, and differs in that the strip 12 is shorter and the hollow tubular cooling element 22 is longer, and the article 402 further comprises a downstream hollow tubular element 27. In the article 402 shown in fig. 14, the length of the strip 12 of aerosol-generating substrate is about 12mm and the length of the hollow tubular cooling element 22 is about 20mm. Thus, the downstream filter segment 24 is located between the hollow tubular cooling element 22 and the downstream hollow tubular element 27. The downstream end 19 of the article 402 is defined by the downstream end of the downstream hollow tubular member 27.

The downstream hollow tubular element 27 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The downstream hollow tubular member 27 defines an inner lumen that extends from the upstream end of the downstream hollow tubular member 27 to the downstream end of the downstream hollow tubular member 27. The lumen is substantially empty and thus a substantially unrestricted air flow is achieved along the lumen. The downstream hollow tubular element 27 may not substantially affect the overall RTD of the aerosol-generating article 402. The length of the downstream hollow tubular element 27 is about 5mm. The wall thickness of the downstream hollow tubular element 27 is about 1mm.

The aerosol-generating article 403 shown in fig. 15 is similar to the aerosol-generating article 402 shown in fig. 14, and differs in that the ventilation zone 36 is provided along the downstream hollow tubular element 27. The ventilation zone 36 is disposed about 2mm from the upstream end of the downstream hollow tubular element 27. The ventilation zone 36 comprises at least one row of circumferential perforations extending through the peripheral wall of the downstream hollow tubular element 27 and any wrapper (not shown) defining the downstream hollow tubular element 27.

Fig. 16 shows an aerosol-generating system 1 comprising an exemplary aerosol-generating device 50 and an aerosol-generating article according to any of the fig. 1 to 15 and described above.

Fig. 16 shows a downstream mouth end portion of an aerosol-generating device 50, where a device cavity is defined and an aerosol-generating article may be received. The aerosol-generating device 50 comprises a housing (or body) 4 extending between a mouth end 2 and a distal end (not shown). The housing 4 comprises an outer peripheral wall 6. The peripheral wall 6 defines a device cavity for receiving the aerosol-generating article 10. The device lumen is defined by a closed distal end and an open mouth end. The mouth end of the device cavity is located at the mouth end of the aerosol-generating device 1. The aerosol-generating article 10 is configured to be received through the open end of the device cavity and to abut the closed end of the device cavity.

The device airflow passage 5 is defined in the peripheral wall 6. The airflow channel 5 extends between an inlet 7 at the mouth end of the aerosol-generating device 1 and the closed end of the device cavity. Air may enter the aerosol-generating substrate 12 via an aperture (not shown) provided at the closed end of the device cavity to ensure fluid communication between the airflow channel 5 and the aerosol-generating substrate 12.

The aerosol-generating device 1 further comprises a heater (not shown) and a power supply (not shown) for supplying power to the heater. A controller (not shown) is also provided to control this supply of power to the heater. The heater is configured to controllably heat the aerosol-generating article during use when the aerosol-generating article is received within the device 1. The heater is preferably arranged to externally heat the aerosol-generating substrate of the aerosol-generating article for optimal aerosol generation. The ventilation zone of the aerosol-generating article is arranged to be exposed when the aerosol-generating article is received within the aerosol-generating device 1.

For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing quantities, amounts, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Moreover, all ranges include the disclosed maximum and minimum points, and include any intervening ranges therein that may or may not be specifically enumerated herein. Thus, in this context, the number a is understood to be ±10% of a. In this context, the number a may be considered to include values within the general standard error of measurement of the property modified by the number a. In some cases, as used in the appended claims, the number a may deviate from the percentages recited above, provided that the amount of deviation a does not materially affect the basic and novel characteristics of the claimed invention. Moreover, all ranges include the disclosed maximum and minimum points, and include any intervening ranges therein that may or may not be specifically enumerated herein.

Claims

1. An aerosol-generating article comprising:

A rod of aerosol-generating substrate, wherein the aerosol-generating substrate comprises tobacco material having a bulk density of less than 350 mg/cc; and

A downstream section disposed downstream of the strip of aerosol-generating substrate, the downstream section comprising a hollow tubular element abutting a downstream end of the strip of aerosol-generating substrate, and the downstream section having a length of at least 40 millimeters.

2. An aerosol-generating article according to claim 1, wherein the strips of aerosol-generating substrate have a length of at least 17 mm.

3. An aerosol-generating article according to claim 1 or 2, wherein the tobacco material has an average density of less than 300 mg/cc.

4. An aerosol-generating article according to any preceding claim, wherein the tobacco material has an average density of at least 100 mg/cc.

5. An aerosol-generating article according to any preceding claim, wherein the ratio of the length of the strip of aerosol-generating substrate to the total length of the aerosol-generating article is at least 0.2, preferably at least 0.25.

6. An aerosol-generating article according to any preceding claim, wherein the strips of aerosol-generating substrate have a length of less than 30 mm.

7. An aerosol-generating article according to any preceding claim, wherein the downstream section has a length of at least 45 mm.

8. An aerosol-generating article according to any preceding claim, wherein the strips of aerosol-generating substrate have a length of at least 20mm.

9. An aerosol-generating article according to any preceding claim, further comprising a ventilation zone at a location along the hollow tubular element of the downstream section.

10. An aerosol-generating article according to any preceding claim, wherein the hollow tubular element of the downstream section has a wall thickness of less than 0.5 mm.

11. An aerosol-generating article according to any preceding claim, wherein the ratio of the length of the hollow tubular element of the downstream section to the length of the strip of aerosol-generating substrate is at least 1.5.

12. An aerosol-generating article according to any preceding claim, wherein the ratio of the length of the hollow tubular element of the downstream section to the total length of the aerosol-generating article is at least 0.5.

13. An aerosol-generating article according to any preceding claim, wherein the hollow tubular element has a length of at least 25 mm.

14. An aerosol-generating article according to any preceding claim, wherein the hollow tubular element has a length of at least 45 mm.

15. An aerosol-generating article according to any preceding claim, wherein the aerosol-generating substrate comprises shredded tobacco material.