KR20240114288A - Aerosol-generating articles comprising hollow tubular substrate elements - Google Patents

Abstract

The aerosol-generating article (10) (110) includes: an aerosol-generating substrate (12) comprising a hollow tubular substrate element (40) (140) having a multi-layer peripheral wall surface (42) defining longitudinal airflow channels (44) (144). ), the peripheral wall 42 is formed of a plurality of overlapping layers of homogenized tobacco material, and the longitudinal airflow channels 44 (144) have a diameter of at least 3 mm; and a downstream section (14) provided downstream of the aerosol-generating substrate (12).

Description

Aerosol-generating articles comprising hollow tubular substrate elements

The present invention relates to an aerosol-generating article comprising an aerosol-generating substrate configured to generate an inhalable aerosol when heated.

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. Typically, in such heated smoking articles, the aerosol is subject to heat transfer from the heat source to a physically separate aerosol-generating substrate or material that is in contact with the heat source and may be located within, around, or downstream of the heat source. It is caused by During use of the aerosol-generating article, volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source and are entrained in the air drawn through the aerosol-generating article. As the released compounds cool, they condense and 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 aerosols are generated by heat transfer from one or more electrical heater elements of the aerosol-generating device to the aerosol-generating substrate of the heated aerosol-generating article. For example, electrically heated aerosol-generating devices have been proposed that include internal heater blades adapted for insertion within an aerosol-generating substrate. The use of aerosol-generating articles in combination with external heating systems is also known. For example, WO-A-2020/115151 describes the provision of one or more heating elements arranged around the periphery of an aerosol-generating article when the article is received within a cavity of an aerosol-generating device. As an alternative, an inductively heatable aerosol-generating article comprising an aerosol-generating substrate and a susceptor arranged within the aerosol-generating substrate was proposed by WO-A-2015/176898.

In general, it can be difficult to provide efficient heating of an aerosol-generating substrate over the entire load of substrate. The portion of the substrate closest to the heating element will inevitably be heated most effectively, and incomplete transfer of heat through the substrate will mean that the portion of the substrate furthest from the heating element may not be heated effectively. Accordingly, the generation of aerosols from those parts of the substrate that are not heated effectively is not optimal, and in some cases, parts of the substrate may not reach a sufficiently high temperature for aerosols to be generated during use. For example, if an external heating element is used to heat a rod of aerosol-generating substrate, as discussed above, the central portion of the rod of aerosol-generating substrate is not likely to generate as many aerosols as the outer portion of the rod, and some In some cases, no aerosol may be generated at all. Therefore, overall, the generation of aerosol from an aerosol-generating rod is likely to be inefficient with some of the aerosol-generating substrate potentially being wasted.

Accordingly, it would be desirable to provide an aerosol-generating article having an aerosol-generating substrate that is tailored to provide more efficient aerosolization of the aerosol-generating substrate and that reduces waste of substrate materials such as cigarettes. In particular, it would be desirable to provide articles that have a relatively simple design so that they can be manufactured in a cost-effective manner and integrated into existing product designs. Moreover, it would be desirable to provide such articles that are readily adaptable so that they can be heated in various types of heating devices, including induction and resistance heating devices.

The present disclosure relates to aerosol-generating articles. The aerosol-generating article may comprise an aerosol-generating substrate comprising hollow tubular substrate elements. The hollow tubular substrate element can have multilayer peripheral walls defining longitudinal airflow channels. The peripheral wall may be formed from multiple overlapping layers of homogenized tobacco material. The longitudinal airflow channel may have a diameter of at least 3 mm. The aerosol-generating article may include a downstream section provided downstream of the aerosol-generating substrate.

According to the present invention, an aerosol-generating article is provided, the aerosol-generating article comprising: a hollow tubular substrate element having a multi-layer peripheral wall defining a longitudinal airflow channel, the peripheral wall comprising a plurality of homogenized tobacco materials; wherein the aerosol-generating substrate is formed of overlapping layers of and the longitudinal airflow channels have a diameter of at least 3 mm; and a downstream section provided downstream of the aerosol-generating substrate.

As used herein, the term “aerosol-generating article” refers to a heated article for producing an aerosol, wherein the article is suitable and intended to be heated or burned to release volatile compounds capable of forming an aerosol. Contains an aerosol-generating substrate. These articles are commonly referred to as heat-not-burn articles. Conventional cigarettes are lit when the user applies a flame to one end of the cigarette and draws air through the other end. The local heat provided by the flame, and the oxygen in the air drawn through the cigarette cause the tip of the cigarette to ignite, and the resulting combustion produces inhalable smoke. In contrast, in a “heated aerosol-generating article” the aerosol is generated by heating the aerosol-generating substrate, rather than burning the aerosol-generating substrate. Known heated aerosol-generating articles include, for example, electrically heated aerosol-generating articles and aerosol-generating articles in which aerosols are generated by heat transfer from a combustible fuel element or heat source to a physically separate aerosol-generating substrate.

Aerosol-generating articles configured for use in an aerosol-generating system that supplies an aerosol-forming agent to the aerosol-generating article are also known. In such systems, the aerosol-generating substrate within the aerosol-generating article contains substantially less aerosol-forming agent compared to the aerosol-generating substrate, which carries and provides substantially all of the aerosol-forming agent used to form the aerosol during operation.

As used herein, the term “aerosol-generating substrate” refers to a substrate that is capable of releasing volatile compounds upon heating that are capable of forming an aerosol. Aerosols generated from the aerosol-generating substrate of the aerosol-generating articles described herein may be visible or invisible and may include vapors (e.g., particulates of materials in a gaseous state, which are usually liquid or solid at room temperature), gases and It may contain droplets of condensed vapor.

As used herein, the term “homogenized plant material” encompasses any plant material formed by agglomeration of particles of a plant. For example, a sheet or web of homogenized tobacco material for the aerosol-generating substrate of the present invention may be formed by agglomerating particles of tobacco material obtained by micronizing, milling or grinding plant material and, optionally, one or more of tobacco leaf blades and tobacco petioles. You can. Homogenized plant material may be produced by casting, extrusion, papermaking processes, or any other suitable process known in the art.

As defined above, the present invention provides an aerosol-generating article having a novel aerosol-generating substrate, in the form of a hollow tubular substrate element. The hollow tubular substrate element is formed from a plurality of overlapping layers of homogenized plant material that combine to form a peripheral wall of the hollow tubular substrate element. The “peripheral” wall of the hollow tubular substrate corresponds to the main wall that defines the tubular structure. Preferably, the hollow tubular substrate element consists only of a peripheral wall. Accordingly, the surrounding wall contains all of the homogenized plant material that will generate aerosols upon heating of the aerosol-generating substrate.

The peripheral walls of the hollow tubular substrate element define longitudinal airflow channels, with the term “longitudinal” referring to the longitudinal axis of the aerosol-generating article. The longitudinal airflow channel has a diameter of at least 3 mm. Preferably, the longitudinal airflow channels are substantially empty, such that there is nothing within the channels that could potentially impede the flow of air and aerosols through the hollow tubular substrate element. In particular, the longitudinal airflow channel is substantially free of tobacco material.

Providing the aerosol-generating substrate in tubular form advantageously allows the amount of tobacco material within the aerosol-generating substrate to be optimized so that aerosols can be efficiently generated from the aerosol-generating substrate upon heating. The tubular form also eliminates the central portion of the homogenized tobacco material, which would potentially not be heated as effectively as the outer portion, especially in aerosol-generating devices containing external heating means. Therefore, overall, the amount of tobacco material can be significantly reduced and tobacco waste can be reduced compared to conventional solid plugs of homogenized tobacco material. For example, the amount of tobacco material used in the hollow tubular substrate element of an aerosol-generating article according to the invention can be reduced by up to 40% compared to the amount of tobacco material used in the solid plug of the substrate in a conventional aerosol-generating article. Meanwhile, it has been shown that similar delivery of aerosols to consumers can be maintained.

The amount of plant material provided to the substrate can be easily adapted by controlling the parameters of the hollow tubular substrate elements, such as the density and wall thickness of the surrounding walls. In this way, it is possible to adapt the hollow tubular substrate element to match the heating zone of the associated aerosol-generating device. Accordingly, the proportion of the aerosol-generating substrate that can be heated to the temperature required for aerosol generation is maximized so that the generation of aerosols from the aerosol-generating substrate is optimized.

The hollow tubular substrate element is formed by multiple overlapping layers of homogenized tobacco material. Preferably, the plurality of overlapping layers of homogenized tobacco material lie directly on top of each other such that adjacent layers are in direct contact with each other without intermediate layers. The plurality of overlapping layers of homogenized tobacco material can advantageously be arranged to define a plurality of voids between adjacent layers. As a result, the surrounding wall typically has a porous structure. As explained in more detail below, the voids defined between adjacent layers of homogenized tobacco material may advantageously provide both transverse and longitudinal porosity, such that aerosols generated upon heating of the aerosol-generating substrate are directed into the longitudinal airflow. It flows through the channel where it is effectively released into the channel and mixed with outside air, which is drawn through the article when the consumer puffs.

The multilayer arrangement of layers additionally provides a relatively dense structure with sufficient structural rigidity to provide an aerosol-generating substrate within the aerosol-generating article without the need for any additional support, such as a carrier layer or internal support members within the longitudinal airflow channels. do.

Providing longitudinal airflow channels with a diameter of at least about 3 mm also advantageously provides greater control over airflow management through the aerosol-generating article.

Hollow tubular substrate elements have a relatively simple structure that can be manufactured in a simple and cost-effective manner using existing equipment. The hollow tubular substrate element can then be incorporated into the aerosol-generating article along with other components using known assembly methods and devices.

Advantageously, if desired, the hollow tubular substrate element can be incorporated directly into the aerosol-generating article without an external wrapper. This provides a unique appearance and texture to the outer surface of the aerosol-generating substrate.

As described above, the hollow tubular substrate element forming the aerosol-generating substrate of the aerosol-generating article according to the invention is formed from a plurality of overlapping layers of homogenized tobacco material. The layers overlap each other laterally to provide a multi-layered structure.

Preferably, the hollow tubular substrate element comprises at least about two overlapping layers of homogenized tobacco material, more preferably at least about three overlapping layers of homogenized tobacco material.

The hollow tubular substrate element preferably comprises at most about 10 overlapping layers of homogenized tobacco material, more preferably at most about 5 overlapping layers of homogenized tobacco material. For example, the hollow tubular substrate element can include from about 2 to about 10 overlapping layers of homogenized tobacco material, or from about 3 to about 5 overlapping layers of homogenized tobacco material.

As mentioned above, the peripheral wall surface of the hollow tubular substrate element preferably has a porous structure as a result of voids formed between overlapping layers of homogenized tobacco material. Preferably, the peripheral wall is porous both transversely and longitudinally.

Preferably, the peripheral wall surface of the hollow tubular substrate element has a cross-sectional porosity of at least about 0.3, more preferably at least about 0.35, and most preferably at least about 0.4.

Preferably, the peripheral wall has a cross-sectional porosity of at most about 0.7, more preferably at most about 0.65, and most preferably at most about 0.6.

For example, the cross-sectional porosity of the peripheral wall may be from about 0.3 to about 0.7, or from about 0.35 to about 0.65, or from about 0.4 to about 0.6.

As used herein, the term “porosity” refers to the fraction of void space within an air permeable or porous body. Specifically, in the context of the present invention, the term “cross-sectional porosity” refers to the fraction of empty space in the cross-sectional area of the peripheral wall surface of a hollow tubular substrate element. Cross-sectional porosity is the area fraction of empty space in the transverse cross-sectional area of the surrounding wall. The transverse cross-sectional area of the peripheral wall is the area of the peripheral wall in a plane perpendicular to the longitudinal axis of the hollow tubular substrate element.

The cross-sectional porosity of the peripheral wall allows aerosols to pass transversely through the peripheral wall such that the aerosol can be drawn into and through the longitudinal airflow channel.

Additional details regarding the measurement of cross-sectional porosity in porous or air-permeable bodies can be found in the publication of international patent application WO-A-2016/023965 in the name of the applicant.

Advantageously, transverse cross-sectional porosity may be determined using a digital imaging process. An image of a transverse cross-section of the hollow tubular substrate may be acquired, and a threshold may be applied to distinguish pixels representing the aerosol-forming substrate from pixels representing empty space. The transverse cross-section porosity is calculated according to the following equation: P _o = N _void / N _tot , where P _o is the total porosity of the transverse cross-section area and N _void is the number of pixels representing the empty space inside the transverse cross-section area. is the number, and N _tot is the total number of pixels in the horizontal cross-sectional area.

It should be noted that digital image acquisition may be done by any suitable method, for example using a digital camera or computed tomography. Images may be represented by any suitable image format in full RGB (red-green-blue) color, black and white, or binary (black and white) representation. Preferably, the background of any image is uniform, facilitating detection and removal of the background during image processing. The resolution of any image must be high enough to accurately interpret the shape of the hollow tubular substrate.

Preferably, the peripheral wall of the hollow tubular substrate element has a weight of at least about 200 mg/cm³, more preferably at least about 300 mg/cm³, more preferably at least about 400 mg/cm³, more preferably at least about 500 mg/cm³, more preferably Preferably it has a density of at least about 600 mg/cm³, more preferably at least about 700 mg/cm³, and more preferably at least about 800 mg/cm³.

Preferably, the peripheral walls of the hollow tubular substrate element have a density of less than about 1 g/cm³.

In the context of the present invention, “density” refers to the bulk density of the surrounding wall, including overlapping layers, rather than the density of individual layers. The relatively high density of the peripheral wall maximizes the amount of tobacco material that can be provided for a given length of the aerosol-generating substrate, so that the amount of aerosol generated from the hollow tubular substrate element can be maximized.

Preferably, the peripheral wall has at least about 150 mg of homogenized tobacco material per centimeter of length of the hollow tubular substrate, more preferably at least about 200 mg of homogenized tobacco material per centimeter of length, more preferably at least about 200 mg of homogenized tobacco material per centimeter of length. About 300 mg of homogenized tobacco material, more preferably at least about 400 mg of homogenized tobacco material per centimeter of length, more preferably at least about 500 mg of homogenized tobacco material per centimeter of length, more preferably at least about 600 mg per centimeter of length. Homogenized tobacco material, more preferably at least about 700 mg of homogenized tobacco material per centimeter of length, more preferably at least about 800 mg of homogenized tobacco material per centimeter of length. This is based on measurements taken at 22.5°C and 60% humidity.

Preferably, the longitudinal tensile strength of the hollow tubular substrate element, measured according to TAPPI test method T494 om-01 2006, is between 11 kN/m and 14 kN/m.

Preferably, the axial compressive strength of the hollow tubular substrate element, measured according to the test method described in ASTM D695-15 (2018), is between 7 MPa and 9 MPa.

Preferably, the radial compressive strength of the hollow tubular substrate element, measured according to the test method described in ASTM D2412-11 (2018), is between 7 MPa and 9 MPa.

Preferably, the hollow tubular substrate element has a length of at least about 10 mm, more preferably at least about 12 mm, and more preferably at least about 15 mm.

Preferably, the hollow tubular substrate element has a length of at most about 40 mm, more preferably at most about 37 mm, and more preferably at most about 35 mm.

For example, the hollow tubular substrate element can have a length of about 10 mm to about 40 mm, or about 12 mm to about 37 mm, or about 15 mm to about 35 mm.

As mentioned above, the length of the hollow tubular substrate element can advantageously be matched to the longitudinal dimension of a heating element in a corresponding aerosol-generating device that will be used to heat the aerosol-generating article. In this way, as much of the aerosol-generating substrate as possible can be heated during use, in order to optimize the amount of aerosol that can be generated and reduce the amount of tobacco waste.

Preferably, the ratio between the length of the hollow tubular substrate element and the overall length of the aerosol-generating article is at least about 0.15. More preferably, the ratio between the length of the hollow tubular substrate element and the overall length of the aerosol-generating article is at least about 0.25. More preferably, the ratio between the length of the hollow tubular substrate element and the overall length of the aerosol-generating article is at least about 0.4.

Preferably, the ratio between the length of the hollow tubular substrate element and the overall length of the aerosol-generating article is at most about 0.6. More preferably, the ratio between the length of the hollow tubular substrate element and the overall length of the aerosol-generating article is at most about 0.55. More preferably, the ratio between the length of the hollow tubular substrate element and the overall length of the aerosol-generating article is at most about 0.5.

For example, the ratio between the length of the hollow tubular substrate element and the overall length of the aerosol-generating article can be about 0.15 to about 0.6, more preferably about 0.25 to about 0.55, even more preferably about 0.4 to about 0.5. .

Preferably, the hollow tubular substrate element has an outer diameter of at least about 4 mm, more preferably at least about 4.25 mm, and more preferably at least about 4.5 mm.

Preferably, the hollow tubular substrate element has an outer diameter of at most about 9 mm, more preferably at most about 8 mm, and more preferably at most about 7.5 mm.

For example, the hollow tubular substrate element can have an outer diameter of about 4 mm to about 9 mm, or about 4.25 mm to about 8 mm, or about 4.5 mm to about 7.5 mm.

Preferably, the outer diameter of the hollow tubular substrate element is substantially the same as the outer diameter of the aerosol-generating article.

As previously discussed, the hollow tubular substrate element provides a longitudinal airflow channel defined by the peripheral walls. The longitudinal airflow channel extends between the ends of the hollow tubular substrate element and is preferably open at both the upstream and downstream ends. The open upstream end provides a main air inlet for drawing air through the aerosol-generating article when the consumer puffs the article. The longitudinal airflow channels therefore provide the primary passageway for the flow of air and aerosols through the article.

Preferably, the hollow tubular substrate element provides an unrestricted flow channel. This means that the hollow tubular element provides negligible resistance to draw (RTD). The term “negligible level of RTD” means less than 1 mm H ₂ O per 10 mm length of the hollow tubular element, preferably less than 0.4 mm H 2 O per 10 mm length of the hollow tubular element, more preferably less than 0.4 mm H ₂ O per 10 mm length of the hollow tubular element. Used to describe an RTD of less than 0.1 mm H ₂ O per 10 mm length.

The longitudinal airflow channel has a diameter of at least 3 mm. This corresponds to the inner diameter of the hollow tubular substrate element. Preferably, the longitudinal airflow channel has a diameter of at least about 3.25 mm, more preferably at least about 3.5 mm.

Preferably, the longitudinal airflow channel has a diameter of at most about 7 mm, more preferably at most about 6 mm, and more preferably at most about 5.5 mm.

For example, the longitudinal airflow channel can have a diameter of about 3 mm to about 7 mm, or about 3.25 mm to about 6 mm, or about 3.5 mm to about 5.5 mm.

Providing an airflow channel with a minimum diameter of 3 mm allows the volume of the channel to be large enough to provide the desired level of airflow while also maintaining sufficient wall thickness. This is necessary so that there is a sufficient amount of tobacco material provided within the hollow tubular substrate element and that the hollow tubular substrate element has a sufficiently high rigidity so that it can be self-supporting.

The longitudinal airflow channel may have a constant diameter along the length of the hollow tubular substrate element. However, the diameter of the longitudinal airflow channel may vary along the length of the hollow tubular substrate element.

Preferably, the longitudinal airflow channel has a substantially circular transverse cross-section. Alternatively, the longitudinal airflow channel may have a substantially elliptical transverse cross-section.

Preferably, the ratio of the inner diameter to the outer diameter of the hollow tubular substrate element is at least about 0.4, more preferably at least about 0.45, and more preferably at least about 0.5.

Preferably, the outer diameter of the hollow tubular substrate element and the diameter of the longitudinal airflow channel are configured to provide a desired wall thickness to the peripheral wall. Preferably, the peripheral wall has a wall thickness of at least about 1 mm, more preferably at least about 1.25 mm, and more preferably at least about 1.5 mm.

Preferably, the peripheral wall has a wall thickness of at most about 2.25 mm, more preferably at most about 2 mm, and more preferably at most about 1.8 mm.

For example, the peripheral wall can have a thickness of 1 mm to about 2.25 mm, or about 1.25 mm to about 2 mm, or about 1.5 mm to about 1.8 mm.

Overlapping layers of homogenized tobacco material may be arranged in any suitable manner to provide the desired wall thickness and porosity in the surrounding wall. Each layer of homogenized tobacco material will typically extend at least once around the hollow tubular substrate element, preferably each layer of homogenized tobacco material will extend around the hollow tubular substrate element a plurality of times to build up the structure of the surrounding wall. do.

Preferably, the plurality of layers of homogenized tobacco material are wound helically around the longitudinal axis of the hollow tubular substrate element. This provides a spiral winding structure similar to the layered structure of conventional paper straws. Hollow tubular substrate elements comprising a helical arrangement of layers for use in the present invention can be manufactured using conventional straw making equipment, such as the Hauni Straw Maker (HSM) from Hauni Maschinenbau GmbH.

The use of a helically wound structure provides optimal structural strength to the hollow tubular substrate element, resulting in increased mechanical strength in all directions compared to similar structures with simple longitudinal wrapping. Additionally, the spirally wound arrangement allows higher densities of homogenized tobacco material to be obtained in the peripheral wall. The manufacturing method used to create the helical arrangement of the layers additionally provides greater control over the dimensions of the hollow tubular substrate element, so that there is minimal variation in the outer and inner diameters. This provides greater consistency across products.

The hollow tubular substrate element may optionally include an adhesive to seal adjacent layers together. Suitable adhesives will be known to those skilled in the art. Preferably, the adhesive is a water-based adhesive, for example a water-based starch adhesive or a polyvinyl alcohol (PVOH) adhesive.

In certain embodiments of the invention, the aerosol-generating substrate may further comprise a sealing element at the upstream end of the hollow tubular substrate element that covers the upstream end of the hollow tubular substrate element. Accordingly, in this embodiment, the open upstream end of the hollow tubular substrate element is covered and sealed by a sealing element, such that air cannot be drawn into the longitudinal airflow channel. Accordingly, the sealing element needs to be adapted to be removed or pierced before use in order to open the upstream end of the hollow tubular substrate element and allow air to enter the longitudinal airflow channel.

The peripheral wall surface of the hollow tubular substrate element formed from overlapping layers of homogenized tobacco material is preferably at least partially exposed on the outer surface of the hollow tubular substrate element. Accordingly, the hollow tubular substrate element is preferably unwrapped along at least part of its length. The exterior surface of the perimeter wall must provide an acceptable surface to form the exterior of the aerosol-generating article, and the layered structure may provide a unique appearance and texture.

Alternatively, the hollow tubular substrate element may be overwrapped with at least one wrapper. For example, a hollow tubular substrate element can be overwrapped with a conventional paper wrapper. The hollow tubular substrate element may be overwrapped with a tobacco-containing wrapper, such as a cigarette paper wrapper.

The hollow tubular substrate element is formed from a plurality of layers of homogenized tobacco material, preferably in sheet form. As used herein in connection with the present invention, the term “sheet” describes a laminated element having a width and length substantially greater than its thickness.

The sheets may each individually have a thickness of 100 μm to 600 μm, preferably 150 μm to 300 μm, and most preferably 200 μm to 250 μm.

Homogenized tobacco material contains tobacco particles. Sheets of homogenized tobacco material for use in the present invention contain at least about 40% by dry weight, more preferably at least about 50% by dry weight, more preferably at least about 70% by dry weight, Most preferably it may have a tobacco content of at least about 90% by weight on a dry weight 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 powdered tobacco blades, ground or powdered tobacco petioles, tobacco dust, tobacco fines, and other particulate tobacco by-products formed during the processing, handling and shipping of tobacco. In a preferred embodiment, the tobacco particles are derived substantially entirely from tobacco leaves. In contrast, isolated nicotine and nicotine salts are derived from tobacco, but are not considered tobacco particles for the purposes of this invention and are not included in the percentage of particulate plant material.

The homogenized tobacco material may further include one or more aerosol formers. Upon evaporation, the aerosol former can deliver other vaporized compounds released from the aerosol-generating substrate upon heating, such as nicotine and flavoring agents, in the aerosol. Suitable aerosol formers for inclusion in the homogenized tobacco material are known in the art and include, but are not limited to, polyhydric alcohols such as triethylene glycol, propylene glycol, 1,3-butanediol and glycerol; Esters of polyhydric alcohols such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids such as dimethyl dodecanedioate and dimethyl tetradecanedioate.

The homogenized tobacco material forms an aerosol of about 5% to about 30% by dry weight, such as about 10% to about 25% by dry weight, or about 15% to about 20% by dry weight. It can have its own content. Aerosol formers can act as wetting agents in the homogenized tobacco material.

Two or more overlapping layers of homogenized tobacco material forming the peripheral wall of the hollow tubular substrate element may all be formed from the same homogenized tobacco material. Alternatively, the peripheral wall comprises one or more layers of first homogenized tobacco material and one or more layers of second homogenized tobacco material that are different from the first homogenized tobacco material. Accordingly, the peripheral wall is formed from a combination of at least two different homogenized tobacco materials. The first homogenized tobacco material and the second homogenized tobacco material may have different compositions. For example, the first and second homogenized tobacco materials may have different tobacco contents, different aerosol former contents, or both. Alternatively or additionally, the first and second homogenized tobacco materials are provided with different levels of flavoring agents to provide flavor profiles. Alternatively or additionally, the first homogenized tobacco material and the second homogenized tobacco material may differ from each other in one or more physical parameters including, but not limited to, density, porosity, or thickness.

The use of different homogenized tobacco materials within a hollow tubular substrate element provides greater flexibility compared to the delivery of aerosols when heated. For example, the compositions of the first and second homogenized tobacco materials can be configured to provide delivery of the aerosol at different times or at different rates. The use of different homogenized tobacco materials can also provide improved stability, for example by avoiding the combination of potentially incompatible ingredients.

Preferably, the plurality of layers of homogenized tobacco material comprises one or more sheets of cast leaves.

Preferably, the cast leaves have a porosity at 25°C of about 20% to about 60%, more preferably about 30% to about 50%, more preferably about 35% to about 45%.

Alternatively or in addition to one or more sheets of cast leaf, the plurality of layers of homogenized tobacco material may include one or more layers of fine cigarette paper.

Preferably, the cigarette paper has a porosity of between about 30% and about 80%, more preferably between about 40% and about 70%, more preferably between about 50% and about 60%, at 25°C. .

The perimeter wall may be formed from alternating layers of cast leaf and fine cigarette paper.

The hollow tubular substrate element of the aerosol-generating article according to the invention preferably comprises one or more susceptor elements positioned in contact with the surrounding wall for inductive heating of the homogenized tobacco material during use.

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 placed in an alternating electromagnetic field, the susceptor is heated. Heating of the susceptor element may be the result of at least one of hysteresis losses or 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 within the cavity of the aerosol-generating device, the oscillating electromagnetic field generated by the inductor coil induces an electric current within the susceptor element, thereby heating the susceptor element. In these embodiments, the aerosol-generating device has a magnetic field strength (H- It can generate a fluctuating electromagnetic field with magnetic field intensity). The electrically operated aerosol generating device is preferably capable of generating a fluctuating electromagnetic field with a frequency between 1 and 30 MHz, for example between 1 and 10 MHz, for example between 5 and 7 MHz.

The susceptor element may include any suitable material. The susceptor element may be formed of any material that can be inductively heated to a temperature sufficient to release volatile compounds from the aerosol-generating substrate. Suitable materials for elongated susceptor elements include graphite, molybdenum, silicon carbide, stainless steel, niobium, aluminum, nickel, nickel-containing compounds, titanium, and composites of metallic materials. Some susceptor elements contain metal or carbon. Advantageously, the susceptor element may comprise or consist of ferromagnetic materials, such as ferritic iron, ferromagnetic alloys such as ferromagnetic steel or stainless steel, ferromagnetic particles, and ferrite. Suitable susceptor elements may be or include aluminum. The susceptor element preferably contains 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 can be heated to temperatures exceeding about 250°C.

The susceptor element may include a non-metallic core with a metal layer disposed on the non-metallic core. For example, the susceptor element may include a ceramic core or a metal track formed on the outer surface of the substrate.

Preferably, the hollow tubular substrate element comprises one or more susceptor elements on the surface of the peripheral wall. The hollow tubular substrate element may include one or more susceptor elements within the longitudinal airflow channel and on the inner surface of the peripheral wall. Alternatively or additionally, the hollow tubular substrate element may include one or more susceptor elements on the outer surface of the peripheral wall.

Preferably, the hollow tubular substrate element comprises a tubular susceptor element provided on at least one surface of the peripheral wall. A tubular susceptor element may be provided on the inner surface of the peripheral wall to internally heat the hollow tubular substrate element. Alternatively, a tubular susceptor element may be provided on the outer surface of the hollow tubular substrate element to heat the hollow tubular substrate element externally.

The use of tubular susceptor elements advantageously optimizes the heating of the homogenized tobacco material within the peripheral wall, since the susceptor elements are in contact with a relatively large surface area of the homogenized tobacco material. Due to the tubular shape of the hollow tubular substrate element, the thickness of the substrate is relatively low, allowing heat to be efficiently transferred from the side on which the tubular susceptor element is located through the surrounding wall.

As defined above, in the aerosol-generating article of the invention, an aerosol-generating substrate formed of hollow tubular substrate elements is combined with a downstream section located downstream of the aerosol-generating substrate. The downstream section is preferably located immediately downstream of the aerosol-generating substrate. The downstream section of the aerosol-generating article preferably extends between the aerosol-generating substrate and the downstream end of the aerosol-generating article. A downstream section may include one or more elements, each of which will be described in more detail in this disclosure.

Preferably, the downstream section comprises at least one hollow tubular element. The hollow tubular element can be provided immediately downstream of the aerosol-generating substrate. That is, the hollow tubular element may abut a downstream end of the aerosol-generating substrate. This arrangement optimizes the flow of aerosol from the longitudinal airflow channel of the hollow tubular substrate element into the downstream section and through the aerosol-generating article.

Preferably, the downstream section of the aerosol-generating article comprises a single hollow tubular element. That is, the downstream section of the aerosol-generating article may include only one hollow tubular element.

As used throughout this disclosure, “hollow tubular element” refers to a generally elongated element that defines a lumen or airflow passage along its longitudinal axis. In particular, the term "tubular" will be used hereinafter with reference to a tubular element that defines at least one airflow conduit having a substantially cylindrical cross-section and establishing unobstructed fluid communication between the upstream end of the tubular element and the downstream end of the tubular element. will be. However, it will be appreciated that alternative geometries (eg, alternative cross-sectional shapes) of the tubular element may be possible. The hollow tubular elements may be individual discrete elements of the aerosol-generating article having a defined length and thickness.

In the context of the invention, the hollow tubular element of the downstream section provides an unrestricted flow channel through the airflow passage. This means that the hollow tubular element provides negligible resistance to draw (RTD), as defined above. Therefore, the airflow passage should be free of any components that would impede the flow of air in the longitudinal direction. Preferably, the airflow passageway is substantially empty.

The hollow tubular element of the downstream section provides a hollow cavity downstream of the aerosol-generating substrate, which enhances cooling and nucleation of aerosol particles generated by the aerosol-generating substrate. Accordingly, the hollow tubular element of the downstream section functions as an aerosol cooling element.

The length of the hollow tubular element may be at least about 12 mm. The length of the hollow tubular element may be at least about 15 mm. The length of the hollow tubular element may be at least about 20 mm.

The length of the hollow tubular element of the downstream section may be about 50 mm or less. The length of the hollow tubular element may be about 45 mm or less. The length of the hollow tubular element may be about 40 mm or less.

For example, the length of the hollow tubular element of the downstream section may be about 12 mm to 50 mm. The length of the hollow tubular element may be about 15 mm to 45 mm. The length of the hollow tubular element may be about 20 mm to 40 mm. The length of the hollow tubular element may be approximately 30 mm.

The relatively long hollow tubular element provides and defines a relatively long internal cavity within the downstream section of the aerosol-generating article. Providing relatively long cavities maximizes the nucleation advantages described above, improving aerosol formation and cooling.

The ratio between the length of the hollow tubular element and the length of the hollow tubular element of the downstream section may be about 1.25 or less. Preferably, the ratio between the length of the hollow tubular element and the length of the hollow tubular element of the downstream section may be about 1 or less. More preferably, the ratio between the length of the hollow tubular element and the length of the hollow tubular element of the downstream section may be about 0.75 or less.

The ratio between the length of the hollow tubular substrate element and the length of the hollow tubular element of the downstream section may be at least about 0.25. Preferably, the ratio between the length of the hollow tubular element and the length of the hollow tubular element of the downstream section may be at least about 0.30. More preferably, the ratio between the length of the hollow tubular element and the length of the hollow tubular element of the downstream section may be at least about 0.40.

For example, the ratio between the length of the hollow tubular substrate element and the length of the hollow tubular element of the downstream section can be from about 0.25 to about 1.25, or from about 0.3 to about 1, or from about 0.4 to about 0.75.

The ratio between the length of the hollow tubular elements of the downstream section and the total length of the downstream section may be about 1 or less. Preferably, the ratio between the length of the hollow tubular elements of the downstream section and the total length of the downstream section may be about 0.90 or less. More preferably, the ratio between the length of the hollow tubular elements of the downstream section and the total length of the downstream section may be about 0.85 or less.

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

For example, the ratio between the length of the hollow tubular element of the downstream section and the total length of the downstream section can be from about 0.35 to about 1, or from about 0.45 to about 0.9, or from about 0.5 to about 0.85.

The ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be about 0.80 or less. Preferably, the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be about 0.70 or less. More preferably, the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be about 0.60 or less.

The ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be at least about 0.25. Preferably, the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be at least about 0.30. More preferably, the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be at least about 0.40.

For example, the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article can be from about 0.25 to about 0.8, or from about 0.3 to about 0.7, or from about 0.4 to about 0.6.

The wall thickness of the hollow tubular element of the downstream section may be at least about 100 μm. The wall thickness of the hollow tubular element of the downstream section may be at least about 150 μm. The wall thickness of the hollow tubular element of the downstream section is at least about 200 μm, preferably at least about 250 μm, and even more preferably at least about 500 μm (or 0.5 mm).

The wall thickness of the hollow tubular element of the downstream section may be less than or equal to about 2 mm, preferably less than or equal to about 1.5 mm, and even more preferably less than or equal to about 1.25 mm. The wall thickness of the hollow tubular element of the downstream section may be about 1 mm or less. The wall thickness of the hollow tubular element of the downstream section may be about 500 μm or less.

The wall thickness of the hollow tubular element of the downstream section may be from about 100 μm to about 2 mm, preferably from about 150 μm to about 1.5 mm, and even more preferably from about 200 μm to about 1.25 mm.

Keeping the thickness of the peripheral wall of the hollow tubular element of the downstream section relatively low - so that the aerosol is available to initiate the nucleation process as soon as the aerosol component leaves the aerosol-generating substrate - ensures that the overall internal volume of the hollow tubular element and the hollow To ensure that the cross-sectional surface area of the longitudinal airflow channels of the tubular element is effectively maximized, while at the same time providing the structural necessary for the hollow tubular element to provide some support to the rod of the aerosol-generating substrate as well as to prevent collapse of the aerosol-generating article. strength, and ensures that the RTD of the hollow tubular element is minimized. It is understood that a larger value of the cross-sectional surface area of the cavity of the hollow tubular element is associated with a reduced velocity of the aerosol stream moving along the aerosol-generating article, which is also expected to favor aerosol nucleation. Additionally, by using hollow tubular elements with a relatively small thickness, it would appear possible to substantially prevent the diffusion of the ventilation air before contacting and mixing with the stream of aerosols, which is also understood to be more favorable to the nucleation phenomenon. Indeed, by providing more controllably localized cooling of the stream of volatilized species, it is possible to enhance the effect of cooling on the formation of new aerosol particles.

The hollow tubular element of the downstream section preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating substrate and the outer diameter of the aerosol-generating article.

The hollow tubular element may have an outer diameter of 5 mm to 12 mm, for example 5 mm to 10 mm or 6 mm to 8 mm. Preferably, the hollow tubular element has an outer diameter of 7.2 mm+/-10%.

The hollow tubular element of the downstream section may have a constant inner diameter along the length of the hollow tubular element. However, the inner diameter of the hollow tubular element may vary along the length of the hollow tubular element.

The hollow tubular element of the downstream section may have an internal diameter of at least about 2 mm. For example, the hollow tubular element can have an internal diameter of at least about 2.5 mm, at least about 3 mm, or at least about 3.5 mm. By providing a hollow tubular element with an inner diameter as described above, it is advantageously possible to provide the hollow tubular element with sufficient rigidity and strength.

The hollow tubular element of the downstream section may have an internal diameter of about 10 mm or less. For example, the hollow tubular element can have an internal diameter of less than or equal to about 9 mm, less than or equal to about 8 mm, or less than or equal to about 7.5 mm. By providing a hollow tubular element with an inner diameter as described above, it is advantageously possible to reduce the resistance to suction of the hollow tubular element.

For example, the hollow tubular element of the downstream section can have an internal diameter of about 2 mm to about 10 mm, about 2.5 mm to about 9 mm, about 3 mm to about 8 mm, or about 3.5 mm to about 7.5 mm.

The ratio of the inner diameter of the hollow tubular substrate element to the inner diameter of the hollow tubular element of the downstream section is preferably about 0.8 to about 1.2, more preferably about 0.9 to about 1.1, and most preferably about 1.

Particularly preferably, the inner diameter of the hollow tubular substrate element is substantially equal to the inner diameter of the hollow tubular element of the downstream section.

The hollow tubular element of the downstream section may comprise a paper-based material. The hollow tubular element may include at least one paper layer. The paper can be a very stiff paper. The paper may be crimped paper, such as crimped heat resistant paper or crimped parchment.

Preferably, the hollow tubular element may comprise cardboard. The hollow tubular element may be a cardboard tube. The hollow tubular element can be formed from cardboard. Advantageously, cardboard is a cost-effective material that provides a balance between being deformable 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. Accordingly, the cardboard tube can provide adequate resistance to deformation or compression during use.

The hollow tubular element may be a paper tube. The hollow tubular element may be a tube formed from spirally wound paper. The hollow tubular element can be formed from multiple layers of paper. The paper may have a basis weight of at least about 50 gsm, at least about 60 gsm, at least about 70 gsm, or at least about 90 gsm.

The hollow tubular element of the downstream section may comprise a polymeric material. For example, the hollow tubular element can include a polymer film. The polymer film may include a cellulose film. The hollow tubular element may include low density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers. The hollow tube may include cellulose acetate tow.

When the hollow tubular element includes cellulose acetate tow, the cellulose acetate tow may have a denier per filament of about 2 to about 4 and a total denier of about 25 to about 40.

In some embodiments, an aerosol-generating article according to the invention may include a ventilation zone at a location along the downstream section. More specifically, in those embodiments where the downstream section comprises a tubular element, a ventilation zone may be provided at a location along the tubular element.

In this way, a ventilation cavity is provided downstream of the rod of aerosol-generating substrate. This provides particularly efficient cooling of the aerosol and promotes enhanced nucleation of aerosol particles.

The ventilation zone may typically comprise a plurality of perforations through the peripheral wall of the hollow tubular element. Preferably, the ventilation zone comprises at least one row of circumferential perforations. In some embodiments, the ventilation zone may include two columns of circumferential perforations. For example, perforations can be formed online during manufacture of the aerosol-generating article. Preferably, each column of circumferential perforations includes 8 to 30 perforations.

The downstream section may additionally include mouthpiece elements. The mouthpiece element can be positioned at the downstream end of the aerosol-generating article. The mouthpiece element is preferably positioned downstream of the hollow tubular element of the downstream section described above. The mouthpiece element may extend between the hollow tubular element of the downstream section and the downstream end of the aerosol-generating article.

Providing a mouthpiece element at the downstream end of an aerosol-generating article according to the present invention provides an attractive appearance and mouthfeel to the consumer.

The mouthpiece element may include at least one mouthpiece filter segment formed from a fibrous filtration material. Parameters or properties described in relation to the mouthpiece element as a whole are equally applicable to the mouthpiece filter portion of the mouthpiece element.

The fibrous filtration material may be for filtering aerosols generated from an aerosol-generating substrate. Suitable fibrous filtration materials will be known to those skilled in the art. Particularly preferably, the at least one mouthpiece filter segment comprises a cellulose acetate filter segment formed from cellulose acetate tow.

The mouthpiece element may consist of a single mouthpiece filter segment. The mouthpiece element may include two or more mouthpiece filter segments axially aligned in an abutting end-to-end relationship.

The downstream section may include a mouth distal cavity at the downstream end, downstream of the mouthpiece element, as described above. The mouthpiece cavity may be defined by an additional hollow tubular element provided at the downstream end of the mouthpiece element. The mouth end cavity may be defined by an outer wrapper of the aerosol-generating article, the outer wrapper extending in a downstream direction from (or past) the mouthpiece element.

The mouthpiece element may optionally include a flavoring agent, which may be provided in any suitable form. For example, the mouthpiece element may include one or more capsules, beads or granules of flavoring agent, or threads or filaments loaded with one or more flavoring agents.

Preferably, the mouthpiece element, its mouthpiece filter portion, has a low particulate filtration efficiency.

Preferably, the mouthpiece element is surrounded by a plug wrap. Preferably, the mouthpiece element is not ventilated so that air does not follow the mouthpiece element and enter the aerosol-generating article.

The mouthpiece element preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article. The diameter of the mouthpiece element (or mouthpiece filter portion) may be substantially equal to the outer diameter of the hollow tubular element. As mentioned in this disclosure, the outer diameter of the hollow tubular element may be about 7.2 mm, ±10%.

The diameter of the mouthpiece element can be from about 5 mm to about 10 mm. The diameter of the mouthpiece element may be about 6 mm to about 8 mm. The diameter of the mouthpiece element may be about 7 mm to about 8 mm. The diameter of the mouthpiece element may be approximately 7.2 mm, ±10%. The diameter of the mouthpiece element may be approximately 7.25 mm, ±10%.

Unless otherwise specified, the resistance of attraction (RTD) of a component or aerosol-generating article is measured according to ISO 6565-2015. RTD refers to the pressure required to force air through the entire length of a component. The terms “pressure drop” or “pull resistance” of a component or article may also refer to “resistance to suction.” These terms generally refer to the output of a component at a rate of about 100 rpm per second at the output or downstream end of the component, normally measured at a temperature of about 22°C, a pressure of about 101 kPa (about 760 torr), and a relative humidity of about 60%, according to ISO 6565-2015. Refers to measurements performed under testing at a volumetric flow rate of 17.5 milliliters.

The resistance to draw (RTD) of the downstream section may be at least about 0 mmH ₂ O. The RTD of the downstream section may be at least about 3 mmH ₂ O. The RTD of the downstream section may be at least about 6 mmH ₂ O.

The RTD of the downstream section may be about 12 mmH ₂ O or less. The RTD of the downstream section may be about 11 mmH ₂ O or less. The RTD of the downstream section may be about 10 mmH ₂ O or less.

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

The resistance to draw (RTD) characteristics of the downstream section may be entirely or largely due to the RTD characteristics of the mouthpiece elements of the downstream section. That is, the RTD of the mouthpiece element of the downstream section can completely define the RTD of the downstream section.

The resistance to draw (RTD) of the mouthpiece element may be at least about 0 mmH ₂ O. The RTD of the mouthpiece element may be at least about 3 mmH ₂ O. The RTD of the mouthpiece element may be at least about 6 mmH ₂ O.

The RTD of the mouthpiece element may be about 12 mmH ₂ O or less. The RTD of the mouthpiece element may be about 11 mmH ₂ O or less. The RTD of the mouthpiece element may be about 10 mmH ₂ O or less.

The resistance of suction of the mouthpiece element may be greater than about 0 mmH ₂ O and less than about 12 mmH ₂ O. Preferably, the resistance of draw of the mouthpiece element may be greater than about 3 mmH ₂ O and less than about 12 mmH ₂ O. The resistance to draw of the mouthpiece element may be greater than about 0 mmH ₂ O and less than about 11 mmH ₂ O. Even more preferably, the resistance of draw of the mouthpiece element may be greater than about 3 mmH ₂ O and less than about 11 mmH ₂ O. Even more preferably, the resistance of draw of the mouthpiece element may be greater than about 6 mmH ₂ O and less than about 10 mmH ₂ O. Preferably, the resistance to draw of the mouthpiece element may be about 8 mmH ₂ O.

As mentioned above, the mouthpiece element, or mouthpiece filter portion, may be formed from a fibrous material. The mouthpiece element may be formed from a porous material. The mouthpiece element may be formed from a biodegradable material. The mouthpiece element may be formed from a cellulosic material, such as cellulose acetate. For example, the mouthpiece element may be formed from bundles of cellulose acetate fibers having a denier per filament of about 10 to about 15. For example, the mouthpiece element may be formed from a relatively low density cellulose acetate tow, such as a cellulose acetate tow containing fibers of about 12 denier per filament.

The mouthpiece element may be formed from a polylactic acid-based material. The mouthpiece element may be formed from a bioplastic material, preferably a starch-based bioplastic material. Mouthpiece elements can be manufactured by injection molding or extrusion. Bioplastic-based materials are advantageous because they can provide simple to manufacture and inexpensive mouthpiece element structures with specific and complex cross-sectional profiles, which provide a plurality of mouthpiece element structures extending through the mouthpiece element material that provide appropriate RTD properties. It may contain a relatively large airflow channel.

The mouthpiece element may be formed from a sheet of suitable material that is crimped, bent, corrugated, woven or folded into elements defining a plurality of longitudinally extending channels. Sheets of such suitable materials may be formed from paper, cardboard, polymers such as polylactic acid, or any other cellulosic, paper-based or bioplastic-based material. The cross-sectional profile of these mouthpiece elements may exhibit randomly oriented channels.

The mouthpiece element may be formed in any other suitable manner. For example, the mouthpiece element may be formed as a bundle of longitudinally extending tubes. The longitudinally extending tube may be formed from polylactic acid. Mouthpiece elements can be formed by extrusion, molding, lamination, pouring, or crushing of suitable materials. Accordingly, it is desirable for there to be a low pressure drop from the upstream end of the mouthpiece element to the downstream end of the mouthpiece element.

The length of the mouthpiece element may be at least about 1.5 mm. The length of the mouthpiece element may be at least about 2 mm. The length of the mouthpiece element may be about 7 mm or less. The length of the mouthpiece element may be about 4 mm or less. The length of the mouthpiece element can be from about 1.5 mm to about 7 mm. The length of the mouthpiece element can be from about 2 mm to about 4 mm.

The ratio between the length of the mouthpiece element and the length of the downstream section may be about 0.35 or less. Preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be about 0.30 or less. More preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be about 0.25 or less.

The ratio between the length of the mouthpiece element and the length of the downstream section may be at least about 0.03. Preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be at least about 0.05. More preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be at least about 0.1.

For example, the ratio between the length of the mouthpiece element and the length of the downstream section is about 0.03 to about 0.35, preferably about 0.05 to about 0.30, more preferably about 0.1 to about 0.25.

The ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be about 0.20 or less. Preferably, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be about 0.15 or less. More preferably, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be about 0.1 or less.

The ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be at least about 0.01. Preferably, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be at least about 0.02. More preferably, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be at least about 0.05.

For example, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article is about 0.01 to about 0.2, preferably about 0.02 to about 0.15, more preferably about 0.05 to about 0.1.

In embodiments where the downstream section includes a hollow tubular element and a mouthpiece element, the ratio of the length of the hollow tubular element to the length of the mouthpiece element may be at least about 1.5. That is, the length of the hollow tubular element may be at least about 150% of the length of the mouthpiece. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be at least about 5. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be at least about 7.5.

The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be about 20 or less. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be about 15 or less. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be about 12.5 or less.

For example, the ratio of the length of the hollow tubular element to the length of the mouthpiece element can be from about 1.5 to about 20, or from about 5 to about 15, or from about 7.5 to about 10.

The overall length of the downstream section is preferably at least about 15 mm, more preferably at least about 20 mm, and more preferably at least about 25 mm.

The overall length of the downstream section is preferably less than about 50 mm, more preferably less than about 45 mm, and even more preferably less than about 40 mm.

For example, the downstream section can have an overall length of about 20 mm to about 50 mm, more preferably about 25 mm to about 45 mm, and more preferably about 30 mm to about 40 mm.

The ratio between the total length of the downstream section and the total length of the aerosol-generating article may be about 0.80 or less. Preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be about 0.75 or less. More preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be about 0.70 or less. Even more preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be about 0.65 or less.

The ratio between the length of the downstream section and the overall length of the aerosol-generating article may be at least about 0.30. Preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be at least about 0.40. More preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be at least about 0.50. Even more preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article can be at least about 0.60.

Preferably, the overall length of the aerosol-generating article according to the present invention is at least about 35 mm. More preferably, the overall length of the aerosol-generating article according to the present invention is at least about 40 mm. Even more preferably, the overall length of the aerosol-generating article according to the present invention is at least about 45 mm. Even more preferably, the overall length of the aerosol-generating article according to the present invention is at least about 50 mm.

The overall length of the aerosol-generating article according to the invention is preferably 110 mm or less. More preferably, the overall length of the aerosol-generating article according to the invention is preferably 100 mm or less. Even more preferably, the overall length of the aerosol-generating article according to the invention is preferably less than or equal to 75 mm. Even more preferably, the overall length of the aerosol-generating article according to the invention is preferably 70 mm or less.

For example, the overall length of the aerosol-generating article can be from about 35 mm to about 110 mm, or from about 40 mm to about 100 mm, or from about 45 mm to about 75 mm, or from about 50 mm to about 70 mm.

The aerosol-generating article preferably has an outer diameter of at least 4 mm. Preferably, the aerosol-generating article has an outer diameter of at least 4.5 mm. More preferably, the aerosol-generating article has an outer diameter of at least 5 mm.

Preferably, the aerosol-generating article has an outer diameter of about 9 mm or less. More preferably, the aerosol-generating article has an outer diameter of about 8 mm or less. Even more preferably, the aerosol-generating article has an outer diameter of about 7 mm or less.

For example, the aerosol-generating article can have an outer diameter of about 4 mm to about 9 mm, or about 4.5 mm to about 8 mm, or about 5 mm to about 7 mm.

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

In certain embodiments of the invention, one or more components of the aerosol-generating article are individually surrounded by their own wrapper.

Preferably, the aerosol-generating substrate and downstream section are combined with an outer wrapper, such as a tipping wrapper.

Preferably, the components of the aerosol-generating article according to the invention are made from biodegradable materials.

Preferably, the aerosol-generating article according to the invention as described herein is configured for use in an electrically operated aerosol-generating system in which the aerosol-generating substrate of the heated aerosol-generating article is heated by an electrical heat source.

The heating element of such aerosol-generating device may have any suitable shape for conducting heat. Heating of the aerosol-generating substrate can be accomplished internally, externally, or both. The heating element may preferably be a heater blade or fin configured to be inserted into the substrate, so that the substrate is heated from the inside. The heating element may partially or completely surround the substrate and externally heat the substrate circumferentially from the outside.

The aerosol-generating system may be an electrically operated aerosol-generating system comprising an induction heating device. The induction heating device generally comprises an induction source configured to be coupled to a susceptor, which may be provided external to the aerosol-generating substrate or provided inside the aerosol-generating substrate, as in certain specific embodiments of the invention described above. . The induction source generates an alternating electromagnetic field, which induces magnetization or eddy currents within the susceptor. The susceptor may heat as a result of hysteresis losses or induced eddy currents that heat the susceptor through ohmic or resistive heating.

An electrically operated aerosol-generating system comprising an induction heating device also includes an aerosol-generating article having an aerosol-generating substrate and a susceptor in thermal proximity to the aerosol-generating substrate. Typically, the susceptor is in direct contact with the aerosol-generating substrate, and heat is transferred from the susceptor to the aerosol-generating substrate primarily by conduction. Examples of electrically operated aerosol-generating systems with induction heating devices and aerosol-generating articles with susceptors are described in WO-A1-95/27411 and WO-A1-2015/177255.

Electrically operated aerosol-generating systems may in some cases include an aerosol-generating article as described above, a source of aerosol-forming agent, and means for vaporizing the aerosol-forming agent, preferably a heating element. The source of aerosol former may be a reservoir, which may be refillable or replaceable, present on the aerosol-generating device. While the reservoir is physically separated from the aerosol-generating article, the generated vapor is directed through the aerosol-generating article. The vapor forms contact with the aerosol-generating substrate, releasing volatile compounds such as nicotine and flavoring agents in the particulate plant material, forming an aerosol. Optionally, to assist volatilization of the compounds within the aerosol-generating substrate, the aerosol-generating system may further comprise a heating element that heats the aerosol-generating substrate, preferably in a cooperative manner with the aerosol former. However, in certain embodiments, the heating element used to heat the aerosol-generating article is separate from the heater that heats the aerosol former.

As mentioned above, the hollow tubular substrate element of the aerosol-generating article according to the invention is advantageously adapted so that its length substantially matches the longitudinal dimension of the heating element of the aerosol-generating system intended to be used for heating the aerosol-generating article. It can be. This ensures that the hollow tubular substrate element is heated along substantially its entire length, so that the generation of aerosols from the aerosol-generating substrate can be maximized.

A non-exhaustive list of non-limiting examples is provided below. Any one or more features of these embodiments may be combined with any one or more features of other embodiments, implementations, or aspects described herein.

EX 1. An aerosol-generating article comprising: an aerosol-generating substrate comprising a hollow tubular substrate element having multilayer peripheral walls defining longitudinal airflow channels, the peripheral walls being formed of a plurality of overlapping layers of homogenized tobacco material; and a downstream section provided downstream of the aerosol-generating substrate.

EX2. The aerosol-generating article of Example EX1, wherein the longitudinal airflow channel has a diameter of at least 3 mm.

EX3. The aerosol-generating article of Example EX1 or EX2, wherein the hollow tubular substrate element comprises at least two overlapping layers of homogenized tobacco material.

EX4. An aerosol-generating article according to any of the preceding embodiments, wherein the hollow tubular substrate element comprises up to 10 overlapping layers of homogenized tobacco material.

EX5. The aerosol-generating article of any of the preceding embodiments, wherein the peripheral wall surface of the hollow tubular substrate element has a cross-sectional porosity of at least about 0.3.

EX6. The aerosol-generating article of any of the preceding embodiments, wherein the peripheral wall surface of the hollow tubular substrate element has a cross-sectional porosity of at least about 0.7.

EX7. An aerosol-generating article according to any of the preceding embodiments, wherein the peripheral wall surface of the hollow tubular substrate element has a density of at least 200 mg/cm³.

EX8. An aerosol-generating article according to any of the preceding embodiments, wherein the peripheral wall of the hollow tubular substrate element has a density of less than 1 g/cm³.

EX9. An aerosol-generating article according to any of the preceding embodiments, wherein the peripheral wall of the hollow tubular substrate element provides at least 150 mg of homogenized tobacco material per centimeter of the length of the hollow tubular substrate.

EX10. The aerosol-generating article of any of the preceding examples, wherein the longitudinal tensile strength of the hollow tubular substrate element is between 11 kN/m and 14 kN/m.

EX11. An aerosol-generating article according to any of the preceding embodiments, wherein the axial compressive strength of the hollow tubular substrate element is between 7 MPa and 9 MPa.

EX12. An aerosol-generating article according to any of the preceding examples, wherein the radial compressive strength of the hollow tubular substrate element is between 7 MPa and 9 MPa.

EX13. An aerosol-generating article according to any of the previous embodiments, wherein the hollow tubular substrate element has a length of at most 40 mm.

EX14. An aerosol-generating article according to any of the previous embodiments, wherein the hollow tubular substrate element has a length of at least 10 mm.

EX15. An aerosol-generating article according to any of the preceding embodiments, wherein the ratio between the length of the hollow tubular substrate element and the overall length of the aerosol-generating article is at least 0.15.

EX16. An aerosol-generating article according to any of the preceding embodiments, wherein the ratio between the length of the hollow tubular substrate element and the overall length of the aerosol-generating article is at most 0.6.

EX17. An aerosol-generating article according to any of the previous embodiments, wherein the hollow tubular substrate element has an outer diameter of at least 4 mm.

EX18. An aerosol-generating article according to any of the previous embodiments, wherein the hollow tubular substrate element has an outer diameter of at most 9 mm.

EX19. An aerosol-generating article according to any of the preceding embodiments, wherein the hollow tubular substrate element provides an unrestricted flow channel.

EX20. An aerosol-generating article according to any of the previous embodiments, wherein the longitudinal airflow channels of the hollow tubular substrate element have a diameter of at most 7 mm.

EX21. An aerosol-generating article according to any of the preceding embodiments, wherein the ratio of the inner diameter to the outer diameter of the hollow tubular substrate element is at least 0.4.

EX22. An aerosol-generating article according to any of the preceding embodiments, wherein the peripheral wall has a wall thickness of at least 1 mm.

EX23. An aerosol-generating article according to any of the preceding embodiments, wherein the peripheral wall has a wall thickness of at most 2.25 mm.

EX24. An aerosol-generating article according to any of the preceding embodiments, wherein the plurality of layers of homogenized tobacco material are wound helically about the longitudinal axis of the hollow tubular substrate element.

EX25. An aerosol-generating article according to any of the preceding embodiments, wherein the hollow tubular substrate element further comprises an adhesive for sealing adjacent layers to each other.

EX26. An aerosol-generating article according to any of the preceding embodiments, wherein the aerosol-generating substrate further comprises a sealing element at an upstream end of the hollow tubular substrate element, covering the upstream end of the hollow tubular substrate element.

EX27. An aerosol-generating article according to any of the preceding embodiments, wherein the homogenized tobacco material has a tobacco content of at least 40% by weight on a dry weight basis.

EX28. An aerosol-generating article according to any of the preceding embodiments, wherein the homogenized tobacco material further comprises one or more aerosol formers.

EX29. The aerosol-generating article of Example EX28, wherein the homogenized tobacco material has an aerosol former content of from 5% to about 30% by weight on a dry weight basis.

EX30. An aerosol-generating article according to any of the preceding embodiments, wherein the peripheral wall comprises one or more layers of a first homogenized tobacco material and one or more layers of a second homogenized tobacco material that is different from the first homogenized tobacco material.

EX31. The aerosol-generating article of Example EX30, wherein the first and second homogenized tobacco materials have different tobacco contents.

EX32. The aerosol-generating article of Example EX30 or EX31, wherein the first and second homogenized tobacco materials have different aerosol former contents.

EX33. An aerosol-generating article according to any of the preceding embodiments, wherein the plurality of layers of homogenized tobacco material comprises one or more sheets of cast leaves.

EX34. The aerosol-generating article of Example EX33, wherein the cast leaf has a porosity of 20% to 60%.

EX35. The aerosol-generating article of any of the preceding embodiments, wherein the plurality of layers of homogenized tobacco material comprises one or more layers of cigarette paper.

EX36. The aerosol-generating article of Example EX35, wherein the cigarette paper has a porosity of 30% to 80%.

EX37. An aerosol-generating article according to any of the preceding embodiments, wherein the hollow tubular substrate element includes one or more susceptor elements positioned in contact with the peripheral wall surface.

EX38. The aerosol-generating article of Example EX37, wherein the hollow tubular substrate element includes one or more susceptor elements on the surface of the peripheral wall.

EX39. The aerosol-generating article of Example EX38, wherein the hollow tubular substrate element comprises a tubular susceptor element provided on at least one surface of the peripheral wall.

EX40. An aerosol-generating article according to any of the preceding embodiments, wherein the downstream section comprises a hollow tubular element.

EX41. The aerosol-generating article of Example EX40, wherein the hollow tubular element of the downstream section has a length of 12 mm to 50 mm.

EX42. The aerosol-generating article of Example EX40 or EX41, wherein the ratio between the length of the hollow tubular substrate element and the length of the hollow tubular element of the downstream section is at least 0.25.

EX43. The aerosol-generating article according to any one of Examples EX40 to EX42, wherein the ratio between the length of the hollow tubular substrate element and the length of the hollow tubular element of the downstream section is 1.25 or less.

EX44. The aerosol-generating article according to any one of Examples EX40 to EX43, wherein the ratio between the length of the hollow tubular element of the downstream section and the total length of the downstream section is at least 0.35.

EX45. The aerosol-generating article according to any one of Examples EX40 to EX44, wherein the ratio between the length of the hollow tubular element of the downstream section and the total length of the downstream section is 1 or less.

EX46. The aerosol-generating article according to any one of Examples EX40 to EX45, wherein the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article is at least 0.25.

EX47. The aerosol-generating article according to any one of Examples EX40 to EX46, wherein the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article is less than or equal to 0.8.

EX48. The aerosol-generating article according to any one of Examples EX40 to EX47, wherein the hollow tubular element of the downstream section has a wall thickness of at least 100 μm.

EX49. The aerosol-generating article according to any one of Examples EX40 to EX48, wherein the hollow tubular element of the downstream section has a wall thickness of 2 mm or less.

EX50. The aerosol-generating article according to any one of Examples EX40 to EX49, wherein the hollow tubular element of the downstream section has an internal diameter of 2 mm to 10 mm.

EX51. The aerosol-generating article according to any one of Examples EX40 to EX50, wherein the ratio between the inner diameter of the hollow tubular substrate element and the inner diameter of the hollow tubular element of the downstream section is 0.8 to 1.2.

EX52. An aerosol-generating article according to any of the preceding embodiments, wherein the downstream section further comprises a mouthpiece element.

EX53. The aerosol-generating article of Example EX52, wherein the mouthpiece element comprises at least one segment of fibrous filtration material.

EX54. The aerosol-generating article of Example EX52 or EX53, wherein the downstream section comprises a mouth distal cavity at the downstream end downstream of the mouthpiece element.

EX55. The aerosol-generating article according to any one of Examples EX52 to EX54, wherein the mouthpiece element has a length of 1.5 mm to 7 mm.

EX56. The aerosol-generating article of any one of Examples EX52 to EX55, wherein the ratio between the length of the mouthpiece element and the length of the downstream section is 0.35 or less.

EX57. The aerosol-generating article according to any one of Examples EX52 to EX56, wherein the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article is 0.20 or less.

EX58. The aerosol-generating article of any of the previous embodiments, wherein the RTD of the downstream section is less than or equal to 12 mmH ₂ O.

EX59. An aerosol-generating article according to any of the preceding embodiments, wherein the length of the downstream section is between 20 mm and 50 mm.

EX60. An aerosol-generating article according to any of the preceding embodiments, wherein the ratio between the overall length of the downstream section and the overall length of the aerosol-generating article is less than or equal to 0.80.

EX61. An aerosol-generating article according to any of the preceding embodiments, wherein the components of the aerosol-generating article are made of biodegradable materials.

Specific embodiments will be further described for purposes of illustration only with reference to the accompanying drawings, wherein:
Figure 1 shows a schematic cross-sectional side view of an aerosol-generating article according to a first embodiment of the invention;
Figure 2 shows a schematic cross-sectional side view of an aerosol-generating system comprising an aerosol-generating article and an aerosol-generating device according to a second embodiment of the present invention.

The aerosol-generating article 10 shown in FIG. 1 includes an aerosol-generating substrate 12 and a downstream section 14 positioned downstream of a rod 12 of the aerosol-generating substrate. Accordingly, the aerosol-generating article 10 can be arranged from an upstream or distal end 16 substantially coincident with the upstream end of the aerosol-generating substrate 12 to a downstream or distal end 18 coincident with the downstream end of the downstream section 14. extends until The downstream section 14 includes a hollow tubular element 20 and a mouthpiece element 50.

The aerosol-generating article 10 has an overall length of approximately 45 mm and an outer diameter of approximately 7.2 mm.

The aerosol-generating substrate 12 comprises a hollow tubular substrate element 40 formed from a plurality of layers of homogenized tobacco material wound helically about the longitudinal axis of the hollow tubular substrate element. The layers of homogenized tobacco material include multiple layers of cast leaves alternating with layers of cigarette paper. The hollow tubular substrate element 40 has a peripheral wall 42 formed from overlapping layers of homogenized tobacco material. The peripheral wall 42 defines a central longitudinal airflow channel 44 extending through the hollow tubular substrate element 40 . The upstream end of the airflow channel 44 provides an air inlet through which air can be drawn into the aerosol-generating article during use. The hollow tubular substrate element 40 is not wrapped so that a layer of homogenized tobacco material is visible on the outer surface of the aerosol-generating article.

The hollow tubular substrate element 40 does not contribute substantially to the overall RTD of the aerosol-generating article. Accordingly, the RTD of hollow tubular substrate element 40 is approximately 0 mmH ₂ O.

The hollow tubular element 20 of the downstream section 14 is located immediately downstream of the hollow tubular substrate element 40 , and the hollow tubular element 20 is longitudinally aligned with the aerosol-generating substrate 12 . The upstream end of the hollow tubular element 20 abuts the downstream end of the hollow tubular substrate element 40.

The hollow tubular element 20 is provided in the form of a hollow cylindrical tube made of cellulose acetate tow. The hollow tubular element 20 defines an internal cavity 22 extending from the upstream end of the hollow tubular element 20 all the way to the downstream end of the hollow tubular element 20 . The internal cavity 22 is substantially empty, so that a substantially unrestricted airflow is activated along the internal cavity 22 . The hollow tubular element 20 does not contribute substantially to the overall RTD of the aerosol-generating article 10. Accordingly, the RTD of hollow tubular element 20 is approximately 0 mmH ₂ O.

As shown in Figure 1, the inner diameter of the hollow tubular element 20 of the downstream section 14 is substantially the same as the inner diameter of the hollow tubular substrate element 40.

Mouthpiece element 50 extends from the downstream end of hollow tubular element 20 to the downstream or mouth end 18 of aerosol-generating article 10. Mouthpiece element 50 includes low density cellulose acetate filter segments. Mouthpiece elements 50 may be individually wrapped by plug wraps (not shown).

Article 10 includes a hollow tubular element 20 and a tipping wrapper 52 surrounding mouthpiece element 50. A tipping wrapper 52 is placed over the upstream portion of the hollow tubular substrate element 40 to further join the hollow tubular substrate element 40 and the downstream section 14.

The aerosol-generating article 10 is particularly suitable for use with an aerosol-generating device comprising external heating means, which externally heats the aerosol-generating substrate 12. Accordingly, during use, the aerosol-generating article 10 is preferably inserted into a heating cavity of an aerosol-generating device with the outer surface of the hollow tubular substrate element 40 proximate to the heating element or elements within the cavity. Heating the hollow tubular substrate element 40 produces an aerosol from the layer of homogenized tobacco, which, with the air entering the longitudinal airflow channel 44 at the upstream end when the consumer draws the article, is directed to the peripheral wall 42 is drawn into the longitudinal airflow channel 44 of the hollow tubular substrate element 40. The combined air and aerosol are drawn through the aerosol-generating article 10 and delivered to the consumer from the downstream end of the aerosol-generating article 10.

Figure 2 shows an aerosol-generating system 100 comprising an aerosol-generating device 102 and an aerosol-generating article 110 according to a second embodiment of the invention. The aerosol-generating article 110 is similar to that shown in Figure 1 and described above, and has a similar arrangement of components. However, the aerosol-generating article 110 further includes a tubular susceptor element 160 within the longitudinal airflow channel 144 of the hollow tubular substrate element 140. A tubular susceptor element 160 is provided on the inner surface of the longitudinal airflow channel 144.

As shown in FIG. 2 , aerosol-generating device 102 includes a longitudinal heating cavity 104 for receiving an aerosol-generating article 110 . Heating cavity 104 has a closed distal end and an open mouth end. An airflow inlet 106 is provided at the distal end of the cavity to allow air to be drawn through the aerosol-generating article 110 during use. The heating cavity 104 includes an arrangement of inductor coils 108 for inductively heating the tubular susceptor element 160 during use.

The aerosol-generating device 102 includes a power source (not shown) to power the inductor coil 108 when the aerosol-generating article 110 is received within the device 102 and controls the aerosol-generating article 110 during use. It further includes a controller (not shown) for possible heating.

Claims (15)

As an aerosol-generating article,
An aerosol-generating substrate comprising a hollow tubular substrate element having a multi-layered peripheral wall defining a longitudinal airflow channel, wherein the peripheral wall is formed of a plurality of overlapping layers of homogenized tobacco material, wherein the longitudinal airflow channel has a width of at least 3 mm. an aerosol-generating substrate having a diameter; and
An aerosol-generating article comprising a downstream section provided downstream of the aerosol-generating substrate. 2. An aerosol-generating article according to claim 1, wherein the peripheral wall surface of the hollow tubular substrate element has a cross-sectional porosity of at least 0.3. 3. An aerosol-generating article according to claim 1 or 2, wherein the peripheral wall comprises at least one layer of first homogenized tobacco material and at least one layer of second homogenized tobacco material having a different composition than the first homogenized tobacco material. . 4. An aerosol-generating article according to claim 3, wherein the first homogenized tobacco material and the second homogenized tobacco material have different porosity. 5. An aerosol-generating article according to any preceding claim, wherein the plurality of layers of homogenized tobacco material are wound helically about the longitudinal axis of the hollow tubular substrate element. 6. An aerosol-generating article according to any preceding claim, wherein the peripheral wall has a density of at least 200 mg/cm³. 7. An aerosol-generating article according to any preceding claim, wherein the peripheral wall provides at least 150 mg of homogenized tobacco material per centimeter of the hollow tubular substrate element. 8. An aerosol-generating article according to any preceding claim, wherein the aerosol-generating substrate further comprises a susceptor element. 9. An aerosol-generating article according to claim 8, comprising a tubular susceptor element on at least one surface of the hollow tubular substrate element. 10. An aerosol-generating article according to any preceding claim, wherein the outer surface of the hollow tubular substrate element is at least partially exposed on the outer surface of the aerosol-generating article. 11. An aerosol-generating article according to any preceding claim, wherein the hollow tubular substrate element has a length of at least 15 mm. 12. An aerosol-generating article according to any preceding claim, wherein the ratio of the length of the hollow tubular substrate element to the overall length of the article is at least 0.15. 13. An aerosol-generating article according to any preceding claim, wherein the downstream section comprises at least one hollow tubular element. 14. An aerosol-generating article according to claim 13, wherein the ratio between the length of the hollow tubular substrate element and the length of the hollow tubular element of the downstream section is 0.25 to 1.25. 15. An aerosol-generating article according to claim 13 or 14, wherein the downstream section further comprises a mouthpiece element at the downstream end of the article.