KR20210107039A - Aerosol-generating articles with ventilated hollow segments - Google Patents

Abstract

An aerosol-generating article (10) for generating an inhalable aerosol when heated includes a rod of an aerosol-generating substrate (12); a mouthpiece segment (18) comprising a plug of filtering material and arranged downstream of and longitudinally aligned with the rod (12); and a hollow tubular segment 16 between the rod 12 and the mouthpiece segment 18 . The hollow tube segment 16 is longitudinally aligned with the rod 12 and the mouthpiece segment 18 and defines a cavity that extends completely to the upstream end of the mouthpiece segment 18 . The article 10 further includes a ventilation zone 26 at a location along the hollow tubular segment. The equivalent inner diameter of the hollow tubular segment 16 at the location with the ventilation zone 26 is at least about 5 mm. The rod 12 of the aerosol-generating substrate comprises at least one aerosol former, and the rod 12 has an aerosol former content of at least about 10% by dry weight.

Description

Aerosol-generating articles with ventilated hollow segments

The present invention relates to an aerosol-generating article comprising an aerosol-generating substrate and configured to generate an inhalable aerosol upon heating.

Aerosol-generating articles in which an aerosol-generating substrate, such as a tobacco-containing substrate, are heated without burning are known in the art. Typically, in such heated smoking articles, the aerosol is generated by heat transfer from a heat source to an aerosol-generating substrate or material that is physically separate, such substrate or ashes being placed in contact with the heat source, located inside the heat source, or It may be located around the heat source, or it may be located downstream of the heat source. During use of an aerosol-generating article, volatile compounds are released from the aerosol-generating substrate by heat transfer from a heat source and are entrained in air drawn through the aerosol-generating article. As the released compound cools, the compound condenses to form an aerosol.

A number of prior art documents disclose aerosol-generating devices for consuming aerosol-generating articles. Such devices include, for example, electrically heated aerosol-generating devices in which an aerosol is generated by heat transfer from one or more electric heater elements of the aerosol-generating device to the aerosol-generating substrate of the heated aerosol-generating article.

In the past, substrates for heated aerosol-generating articles have typically been produced using shreds, strands, or strips of randomly oriented tobacco material. As an alternative, a rod for a heated aerosol-generating article formed of a crimped sheet of tobacco material has been proposed, for example, in International Patent Application WO-A-2012/164009. The rod disclosed in WO-A-2012/164009 has a longitudinal porosity that allows air to be drawn through the rod. Effectively, the folds of the crimped sheet of tobacco material define a longitudinal channel through the rod.

An alternative rod for heated aerosol-generating articles is known from international patent application WO-A-2011/101164. These rods are formed from strands of homogenised tobacco material that may be formed by casting, rolling, calendering or extruding a mixture comprising particulate tobacco and at least one aerosol former to form a sheet of homogenised tobacco material. In an alternative embodiment, the rod of WO-A-2011/101164 is also a strand of homogenised tobacco material obtained by extruding a mixture comprising particulate tobacco and at least one aerosol former to form a continuous length of homogenised tobacco material. can be formed from

Substrates for heated aerosol-generating articles typically contain an aerosol former, ie an aerosol former that, in use, facilitates the formation of an aerosol and is preferably substantially resistant to thermal degradation at the operating temperature of the aerosol-generating article, or a compound or mixtures of compounds. Examples of suitable aerosol formers include polyhydric alcohols such as propylene glycol, triethylene glycol, 1,3-butanediol and glycerin; 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.

It is also common to include aerosol-generating articles for generating an inhalable aerosol upon heating one or more additional elements assembled with the substrate within the same wrapper. Examples of such additional elements include mouthpiece filtering segments, support elements adapted to impart structural strength to the aerosol-generating article, cooling elements adapted to favor cooling of the aerosol prior to reaching the mouthpiece, and the like. However, although the inclusion of these additional elements has been proposed in view of their advantageous effect, this generally complicates the overall structure of the aerosol-generating article and makes its manufacture more complicated and expensive. In practice, manufacturing such multi-element aerosol-generating articles typically requires rather complex manufacturing and combination machines.

In view of this, an aerosol-generating article having a simpler structure has also been proposed. However, the absence of certain additional components, such as, for example, aerosol cooling elements, may make it more difficult to manufacture aerosol-generating articles that consistently provide satisfactory aerosol delivery and RTD to consumers.

Accordingly, it would be desirable to provide an aerosol-generating article capable of providing a consistently satisfactory aerosol delivery to a consumer during use. It would also be desirable to provide one such improved aerosol-generating article with satisfactory RTD values. It would likewise be desirable to provide one such aerosol-generating article that can be manufactured efficiently and at high speed, preferably with low RTD variability from one article to another. The present invention aims to provide a technical solution adapted to achieve at least one of the above-mentioned desirable results.

According to one aspect of the present invention, there is provided an aerosol-generating article that, when heated, generates an inhalable aerosol, the aerosol-generating article comprising:

rods of aerosol-generating substrates; A mouthpiece segment comprising a plug of filtration material, comprising: a mouthpiece segment arranged downstream of the rod and longitudinally aligned with the first segment; and a hollow tubular segment positioned between the rod and the mouthpiece segment. The hollow tube segment is longitudinally aligned with the rod and mouthpiece segments. The hollow tubular segment also defines a cavity that continuously extends to the upstream end of the mouthpiece segment. The aerosol-generating article further comprises a ventilation zone at a location along the hollow tubular segment. The equivalent inner diameter of the hollow tubular segment at the location of the ventilation zone is at least about 5 mm. The rod of the aerosol-generating substrate comprises at least an aerosol former, and the rod of the aerosol-generating substrate has an aerosol former content of at least about 10% by dry weight.

The term “aerosol-generating article” is used herein to refer to an article in which an aerosol-generating substrate is heated to generate an inhalable aerosol that is delivered to a consumer. As used herein, the term “aerosol-generating substrate” refers to a substrate capable of releasing volatile compounds to generate an aerosol upon heating.

Conventional cigarettes catch fire when a 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 end of the cigarette to ignite, and the resulting combustion produces inhalable smoke. In contrast, in heated aerosol-generating articles, the aerosol is generated by heating a flavor-generating substrate such as tobacco. Known heated aerosol-generating articles include, for example, electrically heated aerosol-generating articles and aerosol-generating articles in which an aerosol is generated by heat transfer to an aerosol-forming material physically separated from a combustible fuel element or heat source. For example, an aerosol-generating article according to the present invention finds particular application in aerosol-generating systems comprising an electrically heated aerosol-generating device having an internal heater blade adapted to be inserted into a rod of an aerosol-generating substrate. Aerosol-generating articles of this type are described in the prior art, for example in EP 0822670.

As used herein, the term “aerosol-generating device” refers to a device comprising a heater element that interacts with the aerosol-generating substrate of an aerosol-generating article to generate an aerosol.

As used herein, the term “tubular segment” is used to denote an elongate element that defines a lumen or airflow passageway along its longitudinal axis. In particular, the term "tubular" will be used hereinafter with reference to a tubular element having a substantially cylindrical cross-section and defining at least one airflow conduit that establishes unobstructed fluid communication between an upstream end of the tubular element and a downstream end of the tubular element. will be. However, it will be appreciated that alternative geometries of the cross-section of the tubular element may be possible.

As used herein, the term “longitudinal” refers to a direction corresponding to the major longitudinal axis of the aerosol-generating article extending between the upstream end and the downstream end of the aerosol-generating article. As used herein, the terms “upstream” and “downstream” describe the relative position of an element, or portion of an element, of an aerosol-generating article with respect to the direction in which the aerosol is transported through the aerosol-generating article during use.

During use, air is drawn longitudinally through the aerosol-generating article. The term “transverse” refers to a direction perpendicular to the longitudinal axis. Any reference to “cross-section” of an aerosol-generating article or component of an aerosol-generating article refers to a cross-section unless otherwise stated.

The term “length” refers to the dimension of a component of the aerosol-generating article in the longitudinal direction. For example, it may be used to indicate the dimension of a rod or elongate tubular element in the longitudinal direction.

The term “thickness of the perimeter wall of the tubular element” is used herein to denote the minimum distance measured between the inner surface and the outer surface of the wall that defines the perimeter of the tubular element. In practice, the distance at a given location is measured along a direction substantially perpendicular locally to the outer and inner surfaces of the tubular element. For a tubular element having a substantially circular cross-section, the distance is measured along a substantially radial direction of the tubular element.

In some embodiments, the thickness of the circumferential wall of the tubular element is constant. In an alternative embodiment, the thickness of the peripheral wall of the tubular element varies along the length of the tubular element. This may be because the tubular element is formed of a material with an irregular surface finish (eg, the tubular element is provided in the form of a cellulose acetate tube). Alternatively, this may be because the tubular element is designed to include a tapered section or the like. In embodiments where the thickness of the circumferential wall of the tubular element varies along the length of the tubular element, the "thickness of the circumferential wall of the tubular element" is the minimum distance between the outer and inner surfaces of the wall at different locations along the length of the tubular element. It is taken as an average value calculated on the basis of several measured values.

In certain embodiments, a particularly important parameter is the thickness of the peripheral wall of the tubular element at the location of the ventilation zone.

The expression "air-impermeable material" is used throughout this specification to mean a material that does not pass fluids, particularly air and smoke, through gaps or pores in the material. When the hollow tubular segment is formed of a material impermeable to air and aerosol particles, the air and aerosol particles drawn through the hollow tubular segment are forced to flow through an airflow conduit defined therein by the hollow tubular segment, but the hollow tubular segment It cannot flow through the perimeter wall of

As used herein, the term “homogenized tobacco material” includes any tobacco material formed by agglomerating particles of tobacco material. A sheet or web of homogenised tobacco material is formed by agglomerating particulate tobacco obtained by grinding or otherwise pulverizing one or both of tobacco leaf lamina and tobacco stem. In addition, the homogenized tobacco material may include trace amounts of one or more of tobacco powder, tobacco fines, and other particulate tobacco by-products formed during the processing, handling, and transportation of tobacco. Sheets of homogenised tobacco material may be made by casting, extrusion, papermaking processes, or any other suitable process known in the art.

The term “porous” is used herein to refer to a material that provides a plurality of pores or openings that allow passage of air through the material.

The term “ventilation level” is used throughout this specification to refer to the volume ratio between the airflow entering an aerosol-generating article through a ventilation zone (ventilation airflow) and the sum of the aerosol airflow and the ventilation airflow. The higher the ventilation level, the more dilute the aerosol stream delivered to the consumer.

As briefly described above, the aerosol-generating article of the present invention comprises a rod of an aerosol-generating substrate; a mouthpiece segment comprising a plug of filtration material, and a hollow tubular segment positioned between the rod and the mouthpiece segment. All three elements are longitudinally aligned. The rod of the aerosol-generating substrate comprises at least one aerosol former.

In contrast to known aerosol-generating articles, rods of aerosol-generating substrates have an aerosol former content of at least about 10% by dry weight. The hollow tubular segment also defines a cavity extending continuously to the upstream end of the mouthpiece segment, and a ventilation zone is provided at a location along the hollow tubular segment. Further, the equivalent inner diameter of the hollow tubular segment is at least about 5 mm.

By providing an aerosol-generating article in which the hollow tubular element is arranged between the rod of the aerosol-generating substrate and the mouthpiece, the hollow tubular element defines a cavity extending completely to the upstream end of the mouthpiece segment, the overall structural complexity of the article being reduced to the existing aerosol-generating article. It can be significantly reduced compared to the generated article. This advantageously simplifies the manufacturing process and reduces the complexity of manufacturing and assembling the devices required to implement the manufacturing process.

One such aerosol-generating article is an aerosol cooling element configured to lower the temperature of a stream of aerosol drawn through the aerosol-generating article, for example as is the case in the aerosol-generating article described in international patent application WO 2013/120565. does not necessarily include

The inventors have found that satisfactory cooling of the aerosol stream that occurs when heating the article and is drawn through the hollow tubular element is achieved by providing a ventilation zone at a location along the hollow tubular segment. Furthermore, the inventors have surprisingly found that the effect of increasing the dilution of the aerosol due to the introduction of ventilation air into the article can be prevented by using a hollow tubular segment having an equivalent inner diameter of at least about 5 mm.

Without wishing to be bound by theory, since the temperature of the aerosol stream is rapidly lowered by the introduction of ventilation air as the aerosol moves towards the mouthpiece segment, the ventilation air is relatively close to the upstream end of the hollow tubular segment (i.e., It is assumed that at a location sufficiently close to the heat source and the rod of the aerosol-generating substrate) it is introduced into the aerosol stream, a dramatic cooling of the aerosol stream is achieved, which has a favorable effect on the condensation and nucleation of the aerosol particles. Accordingly, the overall ratio of aerosol particulate phase to aerosol gas phase can be improved compared to conventional unventilated aerosol-generating articles.

At the same time, the use of a hollow tubular element having an equivalent inner diameter of at least 5 mm (which allows the aerosol to initiate the nucleation process as soon as the aerosol component exits the rod of the aerosol-generating substrate) and the hollow tubular While it is possible to effectively maximize the cross-sectional area of the segment, while simultaneously allowing the hollow tubular segment to have the structural strength necessary to prevent distortion of the aerosol-generating article and provide some support to the rod of the aerosol-generating substrate, the hollow The RTD of the tubular segment can be minimized. It is understood that the greater the value of the cross-sectional area of the cavity of the hollow tubular segment, the lower the velocity of the aerosol stream traveling along the aerosol-generating article, which is advantageous for aerosol nucleation. Indeed, without wishing to be bound by theory, the cooling chamber is effectively provided by providing one such large-volume cavity, as is the case in articles according to the present invention, wherein the nucleation phenomenon is enhanced by slowing the flow of the aerosol stream. As such, it may be advantageous to condense aerosol particles upstream of the mouth end of the article therein.

It is understood that it would be advantageous to provide a sufficiently wide tubular cavity downstream of the rod of the aerosol-generating substrate to form a satisfactory amount of aerosol during use. As a result, a larger fraction of the generated aerosol particles begins to condense before reaching the mouth end of the article.

Indeed, the inventors have surprisingly found that the positive effect of improved nucleation can significantly counteract the less desirable dilution effect, so that satisfactory values of aerosol delivery with an aerosol-generating article according to the invention are consistently achieved . This means that the length of the rod of the aerosol-generating substrate is less than about 40 mm, preferably less than 25 mm, even more preferably less than 20 mm, or the overall length of the aerosol-generating article is less than about 70 mm, preferably less than about 60 mm. , even more preferably less than 50 mm, are particularly advantageous in "short" aerosol-generating articles. As will be appreciated, in such aerosol-generating articles, there is little time and space for the aerosol to form and for the particulate phase of the aerosol to become available for delivery to the consumer.

In addition, since the hollow tubular element does not contribute substantially to the RTD of the aerosol-generating article, in the aerosol-generating article according to the invention the overall RTD of the article is advantageously the length and density of the rod of the aerosol-generating substrate or of the mouthpiece. It can be fine-tuned by adjusting the length and density of the segments of the filtration material. This makes it possible to consistently and very precisely manufacture an aerosol-generating substrate with a predetermined RTD, so that a satisfactory level of RTD can be provided to the consumer even in the presence of ventilation.

The aerosol-generating article according to the present invention can be manufactured in a continuous process that can be performed efficiently at high speed, does not require extensive modification of manufacturing equipment, and is conveniently manufactured on existing production lines for the manufacture of heated aerosol-generating articles. can be

The rod of the aerosol-generating substrate preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article.

Preferably, the rod of the aerosol-generating substrate has an outer diameter of at least 5 mm. The rod of the aerosol-generating substrate may have an outer diameter of from about 5 mm to about 12 mm, such as from about 5 mm to about 10 mm or from about 6 mm to about 8 mm. In a preferred embodiment, the rod of the aerosol-generating substrate has an outer diameter of 7.2 mm +/- 10%.

The rod of the aerosol-generating substrate may have a length of from about 5 mm to about 100 mm. Preferably, the rod of the aerosol-generating substrate has a length of at least about 5 mm, more preferably at least about 7 mm. Additionally or alternatively, the rod of the aerosol-generating substrate preferably has a length of less than about 80 mm, more preferably less than about 65 mm, even more preferably less than about 50 mm. In a particularly preferred embodiment, the rod of the aerosol-generating substrate has a length of less than about 35 mm, more preferably less than about 25 mm, even more preferably less than about 20 mm. In one embodiment, the rod of the aerosol-generating substrate may have a length of about 10 mm. In a preferred embodiment, the rod of the aerosol-generating substrate has a length of about 12 mm.

Preferably, the rod of the aerosol-generating substrate has a substantially uniform cross-section along the length of the rod. Particularly preferably, the rod of the aerosol-generating substrate has a substantially circular cross-section.

In a preferred embodiment, the aerosol-generating substrate comprises one or more crimped sheets of homogenised tobacco material. Preferably, at least one sheet of homogenised tobacco material is textured. As used herein, the term 'textured sheet' refers to a sheet that has been crimped, embossed, engraved, perforated or otherwise deformed. The texturized sheet of homogenised tobacco material for use in the present invention may include a plurality of spaced apart indentations, projections, perforations, or combinations thereof. According to a particularly preferred embodiment of the present invention, the rod of the aerosol-generating substrate comprises a crimped crimped sheet of homogenised tobacco material surrounded by a wrapper.

As used herein, the term 'crimped sheet' is intended as substantially synonymous with the term 'creped sheet' and includes a plurality of substantially parallel ridges or corrugations ( It refers to a sheet with corrugation. Preferably, the crimped sheet of homogenised tobacco material has a plurality of ridges or corrugations substantially parallel to the cylindrical axis of the rod according to the invention. This advantageously facilitates the agglomeration of the crimped sheet of homogenised tobacco material to form a rod. However, it will be appreciated that the crimped sheet of homogenised tobacco material for use in the present invention may alternatively or additionally have a plurality of substantially parallel ridges and corrugations disposed at acute or obtuse angles to the cylindrical axis of the rod. In certain embodiments, sheets of homogenised tobacco material for use in rods of articles of the present invention may be textured substantially uniformly over substantially their entire surface. For example, a crimped sheet of homogenised tobacco material for use in the manufacture of a rod for use in an aerosol-generating article according to the present invention may contain a plurality of substantially parallel ridges or corrugations spaced substantially uniformly across the width of the sheet. may include.

The sheet or web of homogenised tobacco material for use in the present invention is at least about 40% by weight on a dry weight basis, more preferably at least about 60% by weight on a dry weight basis, more preferably at least about 70% by weight on a dry weight basis. , most preferably a tobacco content of at least about 90% by weight on a dry weight basis.

A sheet or web of homogenised tobacco material for use in an aerosol-generating substrate may comprise one or more intrinsic binders, i.e., tobacco endogenous binders, one or more external binders, i.e., tobacco exogenous binders, or combinations thereof, to aid in agglomeration of the particulate tobacco. . Alternatively, or additionally, the sheet of homogenised tobacco material for use in the aerosol-generating substrate comprises tobacco and non-tobacco fibers, aerosol formers, wetting agents, plasticizers, flavoring agents, fillers, aqueous and non-aqueous solvents, and their other additives, including but not limited to combinations.

Suitable external binders for incorporation into sheets or webs of homogenised tobacco material for use in aerosol-generating substrates are known in the art and include, for example, gums such as guar gum, xanthan gum, gum arabic and locust bean gum; cellulosic binders such as, for example, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose and ethyl cellulose; polysaccharides such as, for example, starch, organic acids such as alginic acid, conjugated base salts of organic acids such as sodium alginate, agar and pectin; and combinations thereof.

Suitable non-tobacco fibers for inclusion in sheets or webs of homogenised tobacco material for use in aerosol-generating substrates are known in the art and include cellulosic fibers; soft wood fibers; hard wood fibers; jute fibers; and combinations thereof. Prior to inclusion in a sheet of homogenised tobacco material for use in an aerosol-generating substrate, the non-tobacco fiber may be subjected to mechanical pulping; refining; chemical pulping; bleaching; sulfate pulping; and combinations thereof.

Preferably, the sheet or web of homogenised tobacco material comprises an aerosol former. As used herein, the term "aerosol former" describes any suitable known compound or mixture of compounds that, in use, promotes the formation of an aerosol and is substantially resistant to thermal degradation at the operating temperature of the aerosol-generating article. do.

Suitable aerosol formers are known in the art and include polyhydric alcohols such as propylene glycol, triethylene glycol, 1,3-butanediol and glycerin; 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.

Preferred aerosol formers are polyhydric alcohols such as propylene glycol, triethylene glycol, 1,3-butanediol or mixtures thereof, most preferably glycerin.

The sheet or web of homogenised tobacco material may comprise a single aerosol former. Alternatively, the sheet or web of homogenised tobacco material may comprise a combination of two or more aerosol formers.

The sheet or web of homogenised tobacco material has an aerosol former content of greater than 10% on a dry weight basis. Preferably, the sheet or web of homogenised tobacco material has an aerosol former content of greater than 12% on a dry weight basis. Preferably, the sheet or web of homogenised tobacco material has an aerosol former content of greater than 14% on a dry weight basis. Preferably, the sheet or web of homogenised tobacco material has an aerosol former content of greater than 16% on a dry weight basis.

The sheet of homogenised tobacco material may have an aerosol former content of from about 10% to about 30% on a dry weight basis. Preferably, the sheet or web of homogenised tobacco material has an aerosol former content of less than 25% on a dry weight basis.

In a preferred embodiment, the sheet of homogenised tobacco material has an aerosol former content of approximately 20% on a dry weight basis.

Sheets or webs of homogenised tobacco for use in the aerosol-generating article of the present invention may be made by methods known in the art, for example those disclosed in International Patent Application WO-A-2012/164009 A2. In a preferred embodiment, a sheet of homogenised tobacco material for use in an aerosol-generating article is formed by a casting process into a slurry comprising particulate tobacco, guar gum, cellulosic fibers and glycerin.

Alternative arrangements of homogenised tobacco material in rods for use in aerosol-generating articles will be known to those skilled in the art, and include a plurality of laminated sheets of homogenised tobacco material, a plurality formed by winding strips of homogenised tobacco material about their longitudinal axes. may include an elongate tubular element of

As another alternative, the rod of the aerosol-generating substrate may comprise a non-tobacco-based, nicotine-containing material, such as a sheet of adsorbent non-tobacco material loaded with nicotine (eg, in the form of a nicotine salt) and an aerosol former. Examples of such rods are described in international application WO-A-2015/052652. Additionally or alternatively, the rod of the aerosol-generating substrate may comprise a non-tobacco plant material, such as an aromatic non-tobacco plant material.

In the rod of the aerosol-generating substrate of the article according to the invention, the aerosol-generating substrate is preferably surrounded by a wrapper. The wrapper may be formed of a porous or non-porous sheet material. The wrapper may be formed from any suitable material or combination of materials. Preferably, the wrapper is a paper wrapper.

The mouthpiece segment includes a plug of filtration material capable of removing a particulate component, a gas component, or a combination. Suitable filtration materials are known in the art and include, for example, fibrous filtration materials such as cellulose acetate tow, viscose fibers, polyhydroxyalkanoate (PHA) fibers, polylactic acid (PLA) fibers and paper; absorbents such as, for example, activated alumina, zeolites, molecular sieves and silica gel; and combinations thereof. In addition, the plug of filtration material may further comprise one or more aerosol modifiers. Suitable aerosol modifiers are known in the art and include, but are not limited to, flavoring agents such as, for example, menthol. In some embodiments, the mouthpiece may further include a mouth end recess downstream of the plug of filtration material. As an example, the mouthpiece may include a hollow tube arranged in longitudinal alignment with and immediately downstream of the plug of filtration material, the hollow tube being open to the external environment at the downstream end of the mouthpiece and the aerosol-generating article. Form a cavity at the end of the mouth.

The length of the mouthpiece is preferably at least about 4 mm, more preferably at least about 6 mm, even more preferably at least about 8 mm. Additionally or alternatively, the length of the mouthpiece is preferably less than 25 mm, more preferably less than 20 mm, even more preferably less than 15 mm. In a particularly preferred embodiment, the length of the mouthpiece is from about 4 mm to about 25 mm, more preferably from about 6 mm to about 20 mm. In an exemplary embodiment, the length of the mouthpiece is about 7 mm. In another exemplary embodiment, the length of the mouthpiece is about 12 mm.

The hollow tubular segment is preferably an annular tube defining and defining an air gap within the aerosol-generating article. In practice, the hollow tubular segment provides a chamber into which the volatilized aerosol component released by heating of the aerosol-generating substrate accumulates and flows. As briefly described above, this chamber extends continuously in the longitudinal direction to the upstream end of the mouthpiece. This means that no intermediate element is provided between the hollow tubular segment and the mouthpiece, and when the aerosol flowing through the aerosol-generating article reaches the downstream end of the hollow tubular segment, the aerosol flowing through the aerosol-generating article is also at the upstream end of the mouthpiece. It means to reach effectively. More particularly, the aerosol flowing through the aerosol-generating article generally reaches the upstream end of the segment of filtration material of the mouthpiece.

Thus, in an aerosol-generating article according to the present invention, the hollow tubular segment holds the rod of the aerosol-generating substrate at a predetermined distance from the mouthpiece and provides an elongate airflow conduit for the aerosol to form and flow towards the mouthpiece. During use, a thermal gradient is established along these airflow conduits. Indeed, a temperature difference is provided such that the temperature of the volatilized aerosol component entering the hollow tubular segment at the upstream end is greater than the temperature of the volatilized aerosol component exiting the hollow tubular segment at the downstream end (ie, the upstream end of the mouthpiece). Big.

On the other hand, the hollow tubular segment is required to withstand any axial compressive load or bending moment that may be applied on the hollow tubular segment during manufacture of the aerosol-generating article. In addition, the hollow tubular segment is required to impart structural strength to the aerosol-generating article such that it can be easily handled by a consumer and inserted into an aerosol-generating device for use. On the other hand, it is preferred that the overall volume of the chamber defined therein by the hollow tubular element be as large as possible, which favors the formation of the aerosol and improves the delivery of the aerosol to the consumer.

To meet these requirements, as briefly described above, the equivalent inner diameter of the hollow tubular segment is at least about 5 mm. The term “equivalent internal diameter” is used herein to denote the diameter of a circle having the same surface area as the cross-section of the airflow conduit defined internally by the hollow tubular segment. The cross-section of the airflow conduit may have any suitable shape. However, as briefly mentioned above, a circular cross-section is preferred - that is, the hollow tubular segment is effectively a cylindrical tube. In that case, the equivalent inner diameter of the hollow tubular segment effectively coincides with the inner diameter of the cylindrical tube.

More preferably, the equivalent inner diameter of the hollow tubular segment is at least about 5.25 mm, even more preferably at least about 5.5 mm. In some embodiments, the equivalent inner diameter of the hollow tubular segment is at least about 6 mm or at least about 6.5 mm or at least about 7 mm.

Further, the equivalent inner diameter of the hollow tubular segment is preferably less than about 10 mm. More preferably, the equivalent inner diameter of the hollow tubular segment is less than about 9.5 mm, even more preferably less than 9 mm.

The equivalent inner diameter of the hollow tubular segment is measured at the location of the ventilation zone.

In a preferred embodiment, the equivalent inner diameter of the hollow tubular segment is substantially constant along the length of the hollow tubular segment. In other embodiments, the equivalent inner diameter of the hollow tubular segment may vary along the length of the hollow tubular segment.

The inventors have surprisingly found that an aerosol-generating article according to the invention comprising a hollow tubular segment having an equivalent inner diameter within the aforementioned range can provide particularly satisfactory aerosol delivery values. Without wishing to be bound by theory, an aerosol stream flowing along a hollow tubular segment having an equivalent inner diameter falling within the aforesaid range is such that an inlet stream of colder vent air flows at a relatively low velocity when received into the aerosol stream and mixed with the aerosol stream. is assumed to be Because the aerosol stream advances relatively slowly along the hollow tubular segment, the positive impact of cooling on aerosol nucleation is expected to be maximized under these conditions.

Preferably, the equivalent inner diameter of the hollow tubular segment is substantially constant along the length of the hollow tubular segment. However, in some embodiments, the cross-sectional area of the hollow tubular segment may vary along the length of the hollow tubular segment. In this embodiment, the equivalent inner diameter is measured at the location of the ventilation zone.

In a preferred embodiment, the thickness of the peripheral wall of the hollow tubular segment is less than 1.5 mm. More preferably, the thickness of the peripheral wall of the hollow tubular segment is less than 1250 μm, more preferably less than 1000 μm and most preferably less than 900 μm. In a particularly preferred embodiment, the thickness of the peripheral wall of the hollow tubular segment is less than 800 μm.

Also, or alternatively, the thickness of the peripheral wall of the hollow tubular segment is at least about 100 μm. Preferably, the thickness of the peripheral wall of the hollow tubular segment is at least about 200 μm.

Without wishing to be bound by theory, it is advantageous to limit or even substantially prevent the diffusion of ventilation air prior to contacting and mixing with the aerosol stream, by using a hollow tubular segment having a perimeter wall having a thickness falling within the foregoing range. It may seem possible. It is understood that this is more advantageous for the nucleation phenomenon. Indeed, by more controllably locally cooling the stream of volatilized species drawn through the hollow tubular segment, it is possible to enhance the cooling effect as new aerosol particles are formed.

As briefly mentioned above, the aerosol-generating article according to the present invention comprises a ventilation zone at a location along the hollow tubular segment. Preferably, the ventilation zone is provided at a location less than about 18 mm from the upstream end of the hollow tubular segment. Preferably, the distance between the ventilation zone and the upstream end of the hollow tubular segment is less than about 15 mm. Even more preferably, the distance between the ventilation zone and the upstream end of the hollow tubular segment is less than about 10 mm.

Additionally or alternatively, the distance between the ventilation zone and the upstream end of the hollow tubular segment is preferably at least 2 mm. More preferably, the distance between the ventilation zone and the upstream end of the hollow tubular segment is at least about 4 mm. Even more preferably, the distance between the ventilation zone and the upstream end of the hollow tubular segment is at least about 6 mm.

Preferably, the ventilation zone is provided at a location of at least 2 mm from the upstream end of the mouthpiece along the hollow tubular segment. Preferably, the ventilation zone is provided at a location of at least 4 mm from the upstream end of the mouthpiece along the hollow tubular segment. Even more preferably, the ventilation zone is provided at a location of at least 6 mm from the upstream end of the mouthpiece along the hollow tubular segment.

When the mixture of aerosol particles and air flowing through the aerosol-generating article reaches the ventilation zone, outside air drawn through the ventilation zone into the hollow tubular segment mixes with the aerosol. This rapidly reduces the temperature of the aerosol mixture while partially diluting the mixture of air and aerosol particles. However, as will be discussed in more detail below, by providing a ventilation zone at a distance from the upstream end of the mouthpiece segment falling within the foregoing range, a cooling chamber is effectively provided immediately upstream of the mouthpiece, wherein the nuclei of the aerosol particles Formation and growth are advantageously preferred. As such, the diluting effect of the ventilation air entering the hollow tubular segment is at least partially counteracted, which advantageously makes it possible to provide the consumer with a satisfactory level of aerosol delivery.

In some embodiments, the ratio between the distance between the ventilation zone and the upstream end of the hollow tubular segment and the equivalent inner diameter of the hollow tubular segment at the location of the ventilation zone is less than 4. Preferably, the ratio between the distance between the ventilation zone and the upstream end of the hollow tubular segment and the equivalent inner diameter of the hollow tubular segment at the location of the ventilation zone is less than 3.5. More preferably, the ratio between the distance between the ventilation zone and the upstream end of the hollow tubular segment and the equivalent inner diameter of the hollow tubular segment at the location of the ventilation zone is less than three. Even more preferably, the ratio between the distance between the ventilation zone and the upstream end of the hollow tubular segment and the equivalent inner diameter of the hollow tubular segment at the location of the ventilation zone is less than 2.5.

In a particularly preferred embodiment, the ratio between the distance between the ventilation zone and the upstream end of the hollow tubular segment and the equivalent inner diameter of the hollow tubular segment at the location of the ventilation zone is less than 2, more preferably less than 1.5, even more preferably 1.2 is less than

Preferably, the ventilation zone is provided at a location of at least 10 mm from the downstream end of the mouthpiece segment along the hollow tubular segment. More preferably, the ventilation zone is provided at a location of at least 12 mm from the downstream end of the mouthpiece segment along the hollow tubular segment. Even more preferably, the ventilation zone is provided at a location of at least 15 mm from the downstream end of the mouthpiece segment along the hollow tubular segment. This is advantageous in that it ensures that, during use, the ventilation zone is not obscured by the lips of the consumer.

Additionally, or alternatively, the ventilation zone is preferably at a location less than 25 mm from the downstream end of the mouthpiece segment along the hollow tubular segment. More preferably, the ventilation zone is located less than 20 mm from the downstream end of the mouthpiece segment along the hollow tubular segment. This allows the ventilation zone to protrude outwardly of the heating chamber along the hollow tubular segment so that, during use, the external cooling air can be easily drawn into the hollow tubular segment when the aerosol-generating article is received within the heating chamber of the electrically heated aerosol-generating device. It advantageously ensures that it is positioned effectively.

In some preferred embodiments, the ventilation zone is at a location along the hollow tubular segment from about 10 mm to about 25 mm from the downstream end of the mouthpiece segment, more preferably from about 12 mm to about 20 mm from the downstream end of the mouthpiece segment. is provided In an exemplary embodiment, the ventilation zone is provided at a location 18 mm from the downstream end of the mouthpiece segment along the hollow tubular segment. In another exemplary embodiment, the ventilation zone is provided at a location 13 mm from the downstream end of the mouthpiece segment along the hollow tubular segment.

The aerosol-generating article may typically have a ventilation level of at least about 10%, preferably at least about 20%.

In a preferred embodiment, the aerosol-generating article has a ventilation level of at least about 30%. More preferably, the aerosol-generating article has a ventilation level of at least about 35%. Additionally or alternatively, the aerosol-generating article preferably has a ventilation level of less than about 60%. More preferably, the aerosol-generating article has a ventilation level of less than about 50%. In a particularly preferred embodiment, the aerosol-generating article has a ventilation level of from about 30% to about 60%. More preferably, the aerosol-generating article has a ventilation level of from about 35% to about 50%. In some particularly preferred embodiments, the aerosol-generating article has a ventilation level of about 40%.

Without wishing to be bound by theory, the inventors have found that the temperature drop caused by introducing cooler outside air into the hollow tubular segment through the ventilation zone can have a beneficial effect on the nucleation and growth of aerosol particles.

The formation of aerosols from gas mixtures containing various chemical species relies on delicate interactions between coalescence as well as nucleation, evaporation, and condensation, accounting for changes in vapor concentration, temperature, and velocity fields all. The so-called classical nucleation theory is based on the assumption that the fraction of gaseous molecules is large enough to remain cohesive for a long time with sufficient probability (eg, half probability). These molecules represent some sort of critically critical molecular cluster among transient molecular aggregates, indicating that, on average, smaller molecular clusters are more likely to disintegrate into the gas phase rather quickly, while larger clusters are more likely to grow on average. it means. These critical clusters are identified as major nucleation cores from which droplets are expected to grow due to condensation of molecules from the vapor. It is assumed that a pure droplet just nucleated appears to a certain original diameter and then can grow many times. This can be facilitated and enhanced by rapid cooling of the ambient vapor leading to condensation. In this regard, it is helpful to remember that evaporation and condensation are two aspects of one and the same mechanism: gas-liquid mass transfer. While evaporation relates to the net mass transfer from a liquid droplet to the gas phase, condensation is a net mass transfer from the gaseous phase to the droplet phase. Evaporation (or condensation) will shrink (or grow) the droplets, but the number of droplets will not change.

In these scenarios, which can be further complicated by coalescence phenomena, cooling temperature and rate can play an important role in determining how the system responds. In general, since the nucleation process is typically non-linear, different cooling rates can lead to significantly different temporal behaviors with respect to the formation of liquid phases (droplets). Without wishing to be bound by theory, it is hypothesized that cooling may cause a sharp increase in the number concentration of the droplet, which may be followed by a strong and short-lived increase in this growth (nucleation rupture). These nucleation ruptures would appear to be more significant at lower temperatures. It would also appear that a higher cooling rate may be advantageous for an early onset of nucleation. In contrast, a decrease in the cooling rate would appear to have a positive effect on the final size the aerosol droplet ultimately reaches.

Thus, rapid cooling induced by introducing outside air into the hollow tubular segment through the ventilation zone can be advantageously used to favor the nucleation and growth of aerosol droplets. At the same time, however, the introduction of outside air into the hollow tubular segment has the immediate disadvantage of diluting the aerosol stream delivered to the consumer.

The inventors have surprisingly found that the dilution effect on the aerosol - which can in particular be assessed by measuring the effect on the delivery of glycerin comprised in an aerosol-generating substrate as an aerosol former - is advantageously minimized when the ventilation level is between 30% and 50%. found to be In particular, it has been found that ventilation levels of 35% to 42% result in particularly satisfactory glycerin delivery values.

The inventors also found that, in the aerosol-generating article according to the invention, the cooling and diluting effect caused by the introduction of ventilation air at a location along the conduit defined by the aforementioned hollow tubular segment is surprising for the generation and delivery of phenol-containing species. was found to have a reducing effect.

The ventilation zone may include one or more rows of perforations formed through the peripheral wall of the hollow tubular segment. Preferably, the ventilation zone comprises only one row of perforations. It is understood that this is advantageous in that aerosol nucleation can be further enhanced by concentrating the cooling effect caused by ventilation over a short portion of the cavity defined by the hollow tube segment. This is because faster and more dramatic cooling of the stream of volatilized species is expected to be particularly beneficial for the formation of new nuclei of aerosol particles.

Preferably, the one or more rows of perforations are arranged circumferentially around the wall of the hollow tube. When the ventilation zone comprises two or more rows of perforations formed through the peripheral walls of the hollow tubular segments, the rows are longitudinally spaced apart from each other along the hollow tubular segments. As an example, the perforations in adjacent rows may be longitudinally spaced apart from each other by a distance of about 0.25 mm to 0.75 mm.

The equivalent diameter of at least one of the ventilation apertures is preferably at least about 100 μm. Preferably, the equivalent diameter of at least one of the ventilation apertures is at least about 150 μm. Even more preferably, the equivalent diameter of at least one of the ventilation apertures is at least about 200 μm. Additionally or alternatively, the equivalent diameter of at least one of the ventilation apertures is preferably less than about 500 μm. More preferably, the equivalent diameter of at least one of the ventilation apertures is less than about 450 μm. Even more preferably, the equivalent diameter of at least one of the ventilation apertures is less than about 400 μm. The term “equivalent diameter” is used herein to denote the diameter of a circle having the same surface area as the cross-section of the ventilation aperture. The cross-section of the ventilation aperture may have any suitable shape. However, circular ventilation perforations are preferred.

The ventilation perforations may have a uniform size. Alternatively, the ventilation perforations may vary in size. By varying the number and size of ventilation perforations, it is possible to adjust the amount of outside air that is drawn into the hollow tubular segment when the consumer inhales the mouthpiece of the aerosol-generating article during use. As such, it is advantageously possible to adjust the ventilation level of the aerosol-generating article.

Ventilation perforation may be performed by means of any suitable technique, such as laser technology, by means of any suitable technique, such as laser technique, by mechanical perforation of the hollow tubular segment as part of the aerosol-generating article or pre-perforation of the hollow tubular segment prior to being combined with other elements to form the aerosol-generating article. can be formed using Preferably, the ventilation perforation is formed by online laser perforation.

The length of the hollow tubular segment is preferably at least about 10 mm. More preferably, the length of the hollow tubular segment is at least about 15 mm. Additionally or alternatively, the length of the hollow tubular segment is preferably less than about 30 mm. More preferably, the length of the hollow tubular segment is less than about 25 mm. Even more preferably, the length of the hollow tubular segment is less than about 20 mm. In some preferred embodiments, the length of the hollow tubular segment is from about 10 mm to about 30 mm, more preferably from about 12 mm to about 25 mm, even more preferably from about 15 mm to about 20 mm. By way of example, in a particularly preferred embodiment, the length of the hollow tubular segment is about 18 mm. In another particularly preferred embodiment, the length of the hollow tubular segment is about 13 mm.

The overall length of the aerosol-generating article according to the invention is preferably at least about 40 mm. Additionally or alternatively, the overall length of the aerosol-generating article according to the present invention is preferably less than about 70 mm, more preferably less than 60 mm, even more preferably less than 50 mm. In a preferred embodiment, the overall length of the aerosol-generating article is from about 40 mm to about 70 mm. In some embodiments, the overall length of the aerosol-generating article is about 45 mm.

The hollow tubular segment is preferably formed of a substantially air impermeable material. Thus, air and aerosol particles drawn through the hollow tubular segment are forced to flow through the hollow tubular segment from its upstream end to its downstream end, but cannot flow across the peripheral wall of the hollow tubular element.

In some embodiments, the hollow tubular segment includes a wrapper, which also surrounds the rod and mouthpiece segments. In practice, a wrapper having a thickness falling within the foregoing range is used to surround and connect the rod and mouthpiece segments of the aerosol-generating substrate, and the wrapper effectively forms the peripheral wall of the hollow tubular element.

As an example, one such combination wrapper connecting the rod and mouthpiece segments may have a basis weight of at least less than about 70 g/m² (gsm). Preferably, one such combination wrapper connecting the rod and the mouthpiece segment has a basis weight of ^{at least about 80 g/m 2} , more preferably at least about 90 g/m ^{2 .} In a particularly preferred embodiment, the combination wrapper connecting the rod and mouthpiece segments has a basis weight of ^{at least about 110 g/m 2} , more preferably at least about 130 g/m ^{2 .}

In another embodiment, the hollow tubular segment comprises a tube formed of a polymeric material or a cellulosic material, and the heated aerosol-generating article further comprises a wrapper surrounding the rod, tube and mouthpiece segment. By way of example, the cellulosic material may include paper or cardboard or mixtures thereof.

For example, the hollow tubular segment may comprise a tube formed from an extruded plastic tube. Alternatively, the hollow tubular segment may be formed from a plurality of overlapping paper layers, such as a plurality of parallel wound paper layers or a plurality of spirally wound paper layers. Forming the tube from multiple overlapping paper layers may help improve resistance to collapse or deformation. Preferably, the tube comprises at least two layers of paper. Alternatively or additionally, the tube preferably comprises less than 11 paper layers.

One such tube may be made air impermeable using substantially air impermeable paper. The term "substantially air impermeable paper" means less than about 20 CORESTA units, more preferably less than about 10 Coresta units, most preferably about 5 Coresta units, as measured according to ISO 2965:2009. Used herein to refer to paper with less than a unit breathability. Alternatively, adjacent paper layers within the tube may be held with an adhesive that imparts sealing properties to the tube.

Materials suitable for forming the tube are known in the art and ^{include, but include, but are not limited to, cellulose acetate, rigid paper (ie, paper having a basis weight of at least 90 g/m 2} ), polymeric films such as cellulosic films, and cardboard. not limited

In some embodiments, the ratio between the weight of the hollow tubular segment and the volume of the internal cavity defined by the hollow tubular segment is preferably less than 1 mg/mm³. More preferably, the ratio between the weight of the hollow tubular segment and the volume of the inner cavity defined by the hollow tubular segment is less than 0.5 mg/mm³.

In a particularly preferred embodiment, the ratio between the weight of the hollow tubular segment and the volume of the internal cavity defined by the hollow tubular segment is less than 0.25 mg/mm³. More preferably, the ratio between the weight of the hollow tubular segment and the volume of the inner cavity defined by the hollow tubular segment is less than 0.2 mg/mm³. Even more preferably, the ratio between the weight of the hollow tubular segment and the volume of the internal cavity defined by the hollow tubular segment is less than 0.1 mg/mm³.

In a hollow tubular segment having a ratio between the weight of the hollow tubular segment and the volume of an interior cavity defined by the hollow tubular segment falling within the aforementioned range, the hollow tubular segment contributes to the overall structural strength of the aerosol-generating article and is spaced from the mouthpiece The volume of the cavity is advantageously maximized, while ensuring that it effectively retains the load of the aerosol-generating substrate.

In an exemplary embodiment, the hollow tubular segment has an internal equivalent diameter of 7 mm, a weight of 2.5 mg/mm, and is formed of a wrapper having a basis weight of ^{110 g/m 2 .} For one such hollow tubular segment, the ratio between the weight of the hollow tubular segment and the volume of the internal cavity defined by the hollow tubular segment is about 0.065 mg/mm³.

In another exemplary embodiment, the hollow tubular segment has an internal equivalent diameter of 5.3 mm, which may be provided as a cellulose acetate tube having a weight of 9.5 mg/mm. For one such hollow tubular segment, the ratio between the weight of the hollow tubular segment and the volume of the internal cavity defined by the hollow tubular segment is about 0.43 mg/mm³.

In an aerosol-generating article according to the present invention, the overall RTD of the article is essentially dependent on the RTD of the rod and the RTD of the mouthpiece, since the hollow tubular segment is substantially empty, making a substantially negligible contribution to the overall RTD. am. In practice, a hollow tubular segment may be configured to generate an RTD ranging _{from approximately 0 mmH 2} O (about 00 Pa) to approximately 20 mmH _{2 O (about 200 Pa).} Preferably, the hollow tubular segment is _{configured to generate an RTD of about 0 mmH 2} O (about 00 Pa) to about 10 mmH ₂ O (about 100 Pa).

The aerosol-generating article preferably has an overall RTD of less than _{about 90 mmH 2 O (about 900 Pa).} More preferably, the aerosol-generating article has _{an overall RTD of less than about 80 mmH 2} O (about 800 Pa). Even more preferably, the aerosol-generating article has _{an overall RTD of less than about 70 mmH 2} O (about 700 Pa).

Additionally or alternatively, the aerosol-generating article preferably _{has an overall RTD of at least about 30 mmH 2} O (about 300 Pa). More preferably, the aerosol-generating article has _{an overall RTD of at least about 40 mmH 2} O (about 400 Pa). Even more preferably, the aerosol-generating article has _{an overall RTD of at least about 50 mm H2O} (about 500 Pa).

The RTD of an aerosol-generating article can be evaluated as the negative pressure that must be applied to the downstream end of the mouthpiece, under test conditions as defined in ISO 3402, to maintain a constant volumetric flow rate of 17.5 ml/s of air through the mouthpiece. have. The values of the RTDs listed above are intended to be measured on an aerosol-generating article as such (ie prior to insertion of the article into the aerosol-generating device) without blocking the perforation of the ventilation zone.

For example, the length and density (denier per filament count) of the filtration material of the mouthpiece can be adjusted, if desired or required, to achieve a sufficiently high RTD of the aerosol-generating article. Additionally. Or alternatively, the additional filter section may be included within the aerosol-generating article. By way of example, such an additional filter section may be included between the rod and the hollow tubular segment of the aerosol-generating substrate. Preferably, this additional filter section comprises a filtration material such as, for example, cellulose acetate. Preferably, the length of the additional filter section is from about 4 mm to about 8 mm, preferably from about 5 mm to 7 mm.

In some embodiments, an aerosol-generating article according to the present invention may comprise an additional support element arranged between and in longitudinal alignment with the hollow tubular segment and the rod of the aerosol-generating substrate. More particularly, the support element is preferably provided immediately downstream of the rod and immediately upstream of the hollow tubular element.

The support element is provided as a tubular element. The support element may be formed of any suitable material or combination of materials. For example, the support element may include cellulose acetate; cardboard; crimped paper, such as crimped heat-resistant paper or crimped parchment paper; and polymeric materials, such as low density polyethylene (LDPE). In a preferred embodiment, the support element is provided as a hollow cellulose acetate tube.

The support element preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article. The support element may have an outer diameter of from about 5 mm to about 12 mm, for example from about 5 mm to about 10 mm or from about 6 mm to about 8 mm. In a preferred embodiment, the support element has an outer diameter of about 7.2 mm.

The peripheral wall of the support element may have a thickness of at least 1 mm, preferably at least about 1.5 mm, more preferably at least about 2 mm.

The support element may have a length of from about 5 mm to about 15 mm. In a preferred embodiment, the support element has a length of about 8 mm.

During insertion of the heating element of the aerosol-generating device into the aerosol-forming substrate of the aerosol-generating article, the user applies a slight force to overcome the resistance of the aerosol-forming substrate of the aerosol-generating article to insertion of the heating element of the aerosol-generating article. may be requested. This may damage some or all of the aerosol-generating article and the heating element of the aerosol-generating device. Further, the application of a force during insertion of the heating element of the aerosol-generating device into the aerosol-forming substrate of the aerosol-generating article may displace the aerosol-forming substrate within the aerosol-generating article. This may result in the heating element of the aerosol-generating device not being fully inserted into the aerosol-forming substrate, which may result in non-uniform and inefficient heating of the aerosol-forming substrate of the aerosol-generating article. The support element is advantageously configured to resist downstream movement of the aerosol-forming substrate during insertion of the heating element of the aerosol-generating device into the aerosol-forming substrate of the aerosol-generating article.

Preferably, the distance between the ventilation zone and the upstream end of the aerosol-generating article is less than about 50 mm. More preferably, the distance between the ventilation zone and the upstream end of the aerosol-generating article is less than about 45 mm. Even more preferably, the distance between the ventilation zone and the upstream end of the aerosol-generating article is less than about 40 mm.

Additionally, or alternatively, the distance between the ventilation zone and the upstream end of the aerosol-generating article is preferably at least about 12 mm. More preferably, the distance between the ventilation zone and the upstream end of the aerosol-generating article is preferably at least about 15 mm. Even more preferably, the distance between the ventilation zone and the upstream end of the aerosol-generating article is preferably at least about 20 mm. In a particularly preferred embodiment, the distance between the ventilation zone and the upstream end of the aerosol-generating article is preferably at least about 25 mm.

Preferably, the distance between the ventilation zone and the downstream end of the rod of the aerosol-generating substrate is at least about 2 mm. More preferably, the distance between the ventilation zone and the downstream end of the rod of the aerosol-generating substrate is at least about 5 mm. Even more preferably, the distance between the ventilation zone and the downstream end of the rod of the aerosol-generating substrate is at least about 10 mm. In some, particularly preferred embodiments, the distance between the ventilation zone and the downstream end of the rod of the aerosol-generating substrate may be at least about 15 mm.

Additionally or alternatively, the distance between the ventilation zone and the downstream end of the rod of the aerosol-generating substrate is preferably less than about 35 mm. More preferably, the distance between the ventilation zone and the downstream end of the rod of the aerosol-generating substrate is less than about 30 mm. Even more preferably, the distance between the ventilation zone and the downstream end of the rod of the aerosol-generating substrate is less than about 25 mm.

In practice, the ventilation zone comprises a cavity defined therein by the hollow tubular segment, an upstream sub-cavity extending longitudinally from the upstream end of the hollow tubular segment to the location of the ventilation zone, and a downstream end of the hollow tubular segment from the location of the ventilation zone. into downstream subcavities extending longitudinally to Without wishing to be bound by theory, it is stated that in the upstream subcavity, the volatilized species of the aerosol stream are advanced along the hollow tubular segment by yielding some of the heat to the peripheral wall of the hollow tubular segment, where it cools slowly and the aerosol particles begin to form a liquid. it is understood On the other hand, in the downstream sub-cavity, the aerosol stream and ventilation air mix rapidly, which causes rapid cooling of the volatilized species of the aerosol stream, thus nucleation of new aerosol particles and already existing as the aerosol advances towards the mouthpiece. It favors the growth of existing aerosol particles.

Preferably, the ratio between the length of the upstream cavity and the length of the downstream cavity is less than 1.5. More preferably, the ratio between the length of the upstream cavity and the length of the downstream cavity is less than one. Even more preferably, the ratio between the length of the upstream cavity and the length of the downstream cavity is less than 0.67.

Additionally or alternatively, the ratio between the length of the upstream cavity and the length of the downstream cavity is preferably at least about 0.15. More preferably, the ratio between the length of the upstream cavity and the length of the downstream cavity is preferably at least about 0.2. Even more preferably, the ratio between the length of the upstream cavity and the length of the downstream cavity is preferably at least about 0.35.

Similarly, the ventilation zone divides the aerosol-generating article into two sections upstream and downstream of the location of the ventilation zone, respectively.

Preferably, the ratio between the length of the upstream section of the aerosol-generating article and the length of the downstream section of the aerosol-generating article is less than 2.5. More preferably, the ratio between the length of the upstream section of the aerosol-generating article and the length of the downstream section of the aerosol-generating article is less than two. Even more preferably, the ratio between the length of the upstream section of the aerosol-generating article and the length of the downstream section of the aerosol-generating article is less than 1.5. In a particularly preferred embodiment, the ratio between the length of the upstream section of the aerosol-generating article and the length of the downstream section of the aerosol-generating article is less than one.

Additionally or alternatively, the ratio between the length of the upstream section of the aerosol-generating article and the length of the downstream section of the aerosol-generating article is preferably at least about 0.25. More preferably, the ratio between the length of the upstream section of the aerosol-generating article and the length of the downstream section of the aerosol-generating article is at least about 0.33. Even more preferably, the ratio between the length of the upstream section of the aerosol-generating article and the length of the downstream section of the aerosol-generating article is at least about 0.5.

In an aerosol-generating article according to the invention, it is advantageously easy to adjust and control the overall RTD of the article. This is because the overall RTD of the article is finite and depends on the RTD of a small number of components, and the provision of a ventilation zone also contributes to lowering the overall RTD of the article. Thus, it is advantageously possible to reduce the RTD variability between aerosol-generating articles.

Accordingly, the present invention may also provide a pack comprising at least 10 aerosol-generating articles as described above, wherein the RTD of the aerosol-generating article having the highest RTD among the at least 10 aerosol-generating articles and at least 10 aerosols The difference between the RTDs of the aerosol-generating article having the lowest RTD of the generating article is _{less than 10 mmH 2} O (about 100 Pa). Preferably, in one such pack, the difference between the RTD of the aerosol-generating article having the highest RTD of the at least 10 aerosol-generating articles and the RTD of the aerosol-generating article having the lowest RTD of the at least 10 aerosol-generating articles is 9 mmH ₂ O (about 90 Pa), more preferably less than 8 mmH ₂ O (about 80 Pa), even more preferably less than 7 mmH ₂ O (about 70 Pa).

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings, wherein:
1 shows a schematic cross-sectional side view of an aerosol-generating article according to the invention;
2 shows a schematic cross-sectional side view of another example of an aerosol-generating article according to the invention;
3 shows a schematic cross-sectional side view of a further example of an aerosol-generating article according to the invention;

The aerosol-generating article 10 shown in FIG. 1 includes a rod of an aerosol-generating substrate 12 , a hollow cellulose acetate tube 14 , a hollow tubular segment 16 , and a mouthpiece segment 18 . These four elements are arranged in an end-to-end longitudinal alignment and surrounded by a wrapper 20 to form the aerosol-generating article 10 . The aerosol-generating article 10 has a mouth end 22 and an upstream, distal end 24 positioned at an opposite end of the article relative to the mouth end 22 . The aerosol-generating article 10 shown in FIG. 1 is particularly suitable for use with an electrically operated aerosol-generating device comprising a heater for heating a rod of an aerosol-generating substrate.

The rod of the aerosol-generating substrate 12 has a length of about 12 mm and a diameter of about 7 mm. The rod 12 is cylindrical in shape and has a substantially circular cross-section. Rod 12 comprises a crimped sheet of homogenised tobacco material. The sheet of homogenised tobacco material comprises 10% by weight on a dry weight basis of glycerin. The hollow cellulose acetate tube 14 has a length of about 8 mm and a thickness of 1 mm.

Mouthpiece segment 18 includes a plug of cellulose acetate tow of 8 denier per filament and has a length of about 7 mm.

The hollow tubular segment 16 is provided as a cylindrical tube having a length of about 18 mm, and the thickness of the tube wall is about 100 μm.

More specifically, the hollow tubular segment 16 may be formed of, for example, a paper having a basis weight of 110 gsm and may have a weight of 45 mg (ie, a length of 2.5 mg/mm). The equivalent inner diameter of the hollow tubular segment 16 is about 7 mm. Thus, the volume of the cavity defined inside by the hollow tubular segment 16 is about 693 mm³. As such, the ratio between the weight of the hollow tubular segment and the volume of the interior cavity defined by the hollow tubular segment 16 is about 0.065. The aerosol-generating article 10 includes a ventilation zone 26 provided about 5 mm from the upstream end of the mouthpiece segment 18 . Accordingly, the ventilation zone 26 is about 12 mm from the downstream end of the aerosol-generating article and about 13 mm from the upstream end of the hollow tubular segment.

Accordingly, the ventilation zone 26 is about 21 mm from the downstream end of the rod 12 . 2 illustrates another example of an aerosol-generating article according to the present invention. The aerosol-generating article 30 of FIG. 2 has the same structure as the aerosol-generating article 10 of FIG. 1 and differs from the aerosol-generating article 10 only in substantially certain component lengths, and differs from the aerosol-generating article 10 . Only cases will be described below. In the following, the same reference numbers will be used wherever possible for corresponding components having the same structural or functional function.

In the aerosol-generating article 30 of FIG. 2 , the rod 12 and the hollow cellulose acetate tube 14 have the same length as in the aerosol-generating article 10 of FIG. 1 . However, the mouthpiece segment comprises a plug of cellulose acetate tow of 11 denier per filament having a length of about 12 mm, and a hollow tubular segment 14 having a length of about 13 mm. A ventilation zone 26 is provided about 6 mm from the upstream end of the mouthpiece segment 18 and about 7 mm from the upstream end of the hollow tubular segment. Thus, the ventilation zone 26 is about 15 mm from the downstream end of the rod 12 .

In the embodiment of FIG. 2 , the hollow tubular segment 16 has a length of about 18 mm and a circumferential wall thickness of about 1 mm, for example having a weight of 171 mg (ie, a length of 9.5 mg/mm). It may be provided as a cylindrical tube of cellulose acetate.

The equivalent inner diameter of the hollow tubular segment 16 may be about 5.3 mm. Thus, the volume of the cavity defined inside by the hollow tubular segment 16 is about 397 mm³. As such, the ratio between the weight of the hollow tubular segment and the volume of the interior cavity defined by the hollow tubular segment 16 is about 0.43. 3 illustrates another example of an aerosol-generating article according to the present invention. The aerosol-generating article 40 of FIG. 3 is structurally different from the aerosol-generating article 10 of FIG. 1 and the aerosol-generating article 30 of FIG. 2 in that it does not include a hollow cellulose acetate tube as a support element. Accordingly, the lengths of the three main components are also different. In the following, the same reference numbers will be used wherever possible for corresponding components having the same structural or functional function.

In the aerosol-generating article 40 of FIG. 3 , the rod 12 has a length of about 12 mm, the hollow tubular segment 14 has a length of about 26 mm, and the mouthpiece segment 18 has a length of about 12 mm. Includes plugs of cellulose acetate tows having 11 denier per length and filament. A ventilation zone 26 is provided about 5 mm from the upstream end of the mouthpiece segment 18 and about 21 mm from the upstream end of the hollow tubular segment, which in this embodiment is provided with the downstream end of the rod 12 and match

The following examples record the experimental results obtained during tests performed on specific embodiments of aerosol-generating articles according to the present invention. Smoking conditions and smoking machine specifications are specified in ISO standard 3308 (ISO 3308:2000). The atmosphere for condition setting and testing is specified in ISO standard 3402.

Example 1 This experiment was carried out to evaluate the entrainment effect of a hollow tubular segment in which a ventilation zone is provided at a location along the hollow tubular segment according to the invention. The experiment investigated the effect of ventilation levels on the delivery of nicotine and an aerosol former (glycerin). Comparative measurements using a reference aerosol-generating article without ventilation are also provided.

Materials and Methods

Article (A) comprises a rod of a pleated sheet of homogenised tobacco material and an aerosol-generating substrate comprising about 18% by dry weight of glycerin, the rod having a length of 12 mm; A support element in the form of a hollow cellulose acetate tube aligned with and immediately downstream of the rod, the support element having a length of 8 mm; A hollow tubular segment in the form of a cardboard tube aligned with a rod and immediately downstream of the rod, the hollow tubular segment having a length of 13 mm; an aerosol-generating article formed of the mouthpiece segment aligned with the hollow tubular segment and having a length of 12 mm, the mouthpiece segment of filtration material immediately downstream of the hollow tubular segment. A ventilation zone is provided at a location along the hollow tubular segment at 18 mm from the downstream end of the mouthpiece segment. The ventilation level of the aerosol-generating article (A) is 30%.

Article (B) is a reference aerosol-generating article having the same structure as article (A), but without a ventilation zone. Thus, the ventilation level of the aerosol-generating article (B) is 0%.

Nicotine and glycerin delivery is measured by gas chromatography/time-of-flight mass spectrometry (GC/MS-TOF) for nicotine and glycerin collected on a Cambridge filter pad. The run was performed as described in Example 1.

result. The average nicotine and glycerin delivery from articles (A) and (B) are shown in Table 1 below.

Table 1. Effect of ventilation levels on nicotine and glycerin delivery.

Ventilation
[%] nicotine delivery
[mg] glycerin
[mg] Item A 30 1.41 5.6 Item B 0 1.17 3.5

Claims (15)

An aerosol-generating article for generating an inhalable aerosol upon heating, the aerosol-generating article comprising:
rods of aerosol-generating substrates;
a mouthpiece segment comprising a plug of filtration material and arranged downstream of the rod and longitudinally aligned with the rod;
a hollow tubular segment positioned between the rod and the mouthpiece segment and longitudinally aligned with the rod and mouthpiece segment, the hollow tubular segment defining a cavity continuously extending to an upstream end of the mouthpiece segment; and
a ventilation zone positioned along the hollow tubular segment;
the rod of the aerosol-generating substrate has a length of less than about 15 mm;
the overall length of the aerosol-generating article is from about 40 mm to about 70 mm;
the equivalent inner diameter of the hollow tubular segment at the location with the ventilation zone is at least about 5 mm;
An aerosol-generating article wherein the rod of the aerosol-generating substrate comprises at least an aerosol former, wherein the rod of the aerosol-generating substrate has the aerosol former in an amount of at least about 10% by dry weight. The aerosol-generating article of claim 1 , wherein the hollow tubular segment comprises a wrapper and the wrapper also surrounds the rod and mouthpiece segments. The aerosol-generating article of claim 1 , wherein the hollow tubular segment comprises a tube formed of a polymeric material or a cellulosic material, and wherein the heated aerosol-generating article further comprises a wrapper surrounding the rod, tube, and mouthpiece segment. 4. The aerosol-generating article according to any one of claims 1 to 3, wherein the equivalent inner diameter of the hollow tubular segment is substantially constant along the length of the hollow tubular segment. 5 . The aerosol-generating article according to claim 1 , wherein the ventilation zone is at a location of at least 2 mm from the upstream end of the mouthpiece segment along the hollow tubular segment. The aerosol-generating article of claim 4 , wherein the ventilation zone is at a location less than 25 mm from the downstream end of the rod of the aerosol-generating substrate along the hollow tubular segment. 7. The aerosol-generating article according to any one of the preceding claims, wherein the ventilation zone is located along the hollow tubular segment less than about 18 mm from the upstream end of the hollow tubular segment. 8. The aerosol-generating article according to any one of claims 1 to 7, wherein the aerosol-generating article has a ventilation level of at least about 10%. 9. The aerosol-generating article according to any one of claims 1 to 8, wherein the aerosol-generating article has a ventilation level of less than about 60%. 10. The aerosol-generating article according to any one of claims 1 to 9, wherein the hollow tubular segment has a length of from about 10 mm to about 30 mm. 11. The aerosol-generating article according to any one of the preceding claims, wherein the thickness of the peripheral wall of the hollow tubular segment at the location of the ventilation zone is less than about 1.5 mm. 12 . The aerosol-generating article according to claim 1 , wherein the hollow tubular segment has a thickness of at least about 100 μm. 13. The aerosol-generating article of any one of claims 1-12, wherein the RTD of the aerosol-generating article is from about 30 mmH ₂ O to about 90 mmH ₂ O. 14. The aerosol-generating article according to any one of the preceding claims, wherein the distance between the ventilation zone and the upstream end of the hollow tubular segment is less than about 15 mm. 15. The aerosol-generating article according to any one of the preceding claims, wherein the distance between the ventilation zone and the upstream end of the aerosol-generating article is less than about 40 mm.

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