KR20210102283A - Aerosol-generating articles having ventilation cavities - 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 filtration material and arranged downstream of the rod 12 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 16 less than 18 mm from the upstream end of the hollow tubular segment 16 . The thickness of the peripheral wall of the hollow tubular segment 16 is less than about 1.5 mm. The rod 12 of the aerosol-generating substrate comprises at least an aerosol former, and the rod 12 has an aerosol former content of at least about 10% by dry weight. The aerosol-generating article has a ventilation level of at least about 10%.

Description

Aerosol-generating articles having ventilation cavities

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

Aerosol-generating substrates, such as tobacco-containing substrates, are known in the art for aerosol-generating articles that are heated rather than combusted. Typically, in such heated smoking articles, the aerosol is heat from a heat source to a physically separate aerosol-generating substrate or material, which may be located in, in contact with, within the heat source, around the heat source, or downstream of the heat source. caused by transmission. 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.

Substrates for heated aerosol-generating articles have, in the past, typically been made using randomly oriented shreds, strands, or strips of tobacco material. As an alternative, a rod for a heated aerosol-generating article, formed of a corrugated sheet of tobacco material, is 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 corrugated 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. Such rods are formed from strands of homogenized tobacco material, which 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 homogenized tobacco material. have. In an alternative embodiment, the rod of WO-A-2011/101164 is also a homogenized tobacco material obtained by extruding a mixture comprising particulate tobacco and at least one aerosol former to form a continuous length of homogenized tobacco material. It can be formed from a strand of

Substrates for heated aerosol-generating articles typically further comprise an aerosol former, i.e., a compound or mixture of compounds 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. . 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 in aerosol-generating articles for generating an inhalable aerosol upon heating one or more additional elements that assemble with a 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 such an additional element has been proposed in view of its advantageous effect, it generally complicates the overall structure of the aerosol-generating article, making it more complex and expensive to manufacture. 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, in the absence of certain additional components, such as, for example, aerosol cooling elements, it may be more difficult to manufacture an aerosol-generating article that consistently provides a satisfactory aerosol delivery and RTD to the consumer.

Accordingly, it would be desirable to provide an aerosol-generating article that enables the provision of 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 be equally 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 aforementioned desirable results.

According to one aspect of the present invention, there is provided an aerosol-generating article for producing an inhalable aerosol when heated, 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 extends completely 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 less than about 18 mm from the upstream end of the hollow tubular segment. The wall thickness of the peripheral wall of the hollow tubular segment is less than about 1.5 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 denote an article in which an aerosol-generating substrate is heated to generate an inhalable aerosol to the 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 ignite 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 tip 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 peripheral wall of a tubular element" is used herein to denote the minimum distance measured between the outer and inner surfaces 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 peripheral 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 peripheral wall of the tubular element varies along the length of the tubular element, "thickness of the peripheral 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 any embodiment, 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 permit the passage of fluids, particularly air and smoke, through the interstices or pores of 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 internally defined by the hollow tubular segment, but the hollow tubular segment cannot flow across the surrounding walls of

As used herein, the term “homogenized tobacco material” includes any tobacco material formed by the agglomeration of particles of tobacco material. The sheet or web of homogenized tobacco material is formed by agglomerating particulate tobacco obtained by grinding or otherwise pulverizing one or both of tobacco leaf lamina and tobacco stem. The homogenized tobacco material may also 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. The homogenized sheet of tobacco material may be made by casting, extrusion, papermaking, 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 denote the volume ratio between the airflow introduced into the aerosol-generating article through the ventilation zone (ventilation airflow) and the sum of the aerosol airflow and the ventilation airflow. The greater the ventilation level, the higher the dilution of the aerosol stream delivered to the consumer. The ventilation level is measured on an aerosol-generating article as such, ie without inserting the aerosol-generating article into a suitable aerosol-generating device adapted to heat the aerosol-generating substrate.

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 completely to the upstream end of the mouthpiece segment, and a ventilation zone is provided at a location along the hollow tubular segment less than about 18 mm from the upstream end of the hollow tubular segment. Also, the thickness of the peripheral wall of the hollow tubular segment is less than about 1.5 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 the manufacturing and assembly equipment required to implement the manufacturing process.

One such aerosol-generating article is an aerosol cooling element adapted 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 include

The inventors have found that satisfactory cooling of the stream of aerosol generated upon heating the article and drawn through the hollow tubular element is achieved by providing a ventilation zone at a location along the hollow tubular segment. In addition, the inventors surprisingly found that by arranging the ventilation zone at a location less than 18 mm from the upstream end of the hollow tubular segment and using a hollow tubular segment having a peripheral wall with a thickness of less than 1.5 mm, by introducing ventilation air into the article. It has been found that it may be possible to counteract the effect of increased aerosol dilution caused.

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, keeping the thickness of the peripheral wall of the hollow tubular element less than 1.5 mm makes the entire interior volume of the hollow tubular element available to initiate the nucleation process as soon as the aerosol component exits the rod of the aerosol-generating substrate. - and ensuring that the cross-sectional surface area of the hollow tubular element is effectively maximized, while at the same time providing the structural strength necessary for the hollow tubular segment to provide some support to the rod of the aerosol-generating substrate as well as to prevent collapse of the aerosol-generating article. and ensure that the RTD of the hollow tubular segment is minimized. It is understood that a larger value of the cross-sectional surface area of the cavity of the hollow tubular segment is associated with a reduced velocity of the aerosol stream traveling along the aerosol-generating article, which is also expected to favor aerosol nucleation. In addition, by using a hollow tubular segment with a thickness of less than 1.5 mm, it will appear possible to substantially prevent the diffusion of ventilation air prior to contacting and mixing with the stream of aerosol, which is also understood to be more favorable for the nucleation phenomenon. do. Indeed, by providing a 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.

Indeed, satisfactory values of aerosol delivery are consistently achieved with aerosol-generating articles according to the invention, since the inventors have discovered how the beneficial effect of enhanced nucleation can significantly counteract the less positive effect of dilution. 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 in which the aerosol is formed and the particulate phase of the aerosol becomes 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 carried out efficiently at high speed and can be conveniently manufactured on existing production lines for the manufacture of heated aerosol-generating articles without requiring extensive modifications of manufacturing equipment. have.

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 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 corrugated sheets of homogenized tobacco material. Preferably, at least one sheet of homogenized tobacco material is textured. As used herein, the term 'textured sheet' refers to a crimped, embossed, engraved, perforated or otherwise deformed sheet. A texturized sheet of homogenized tobacco material for use in the present invention may include a plurality of spaced apart indentations, protrusions, 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 homogenized tobacco material surrounded by a wrapper.

As used herein, the term 'crimped sheet' is intended to be synonymous with the term 'creped sheet' and has a plurality of substantially parallel ridges or corrugations. point to the sheet. Preferably, the crimped sheet of homogenized 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 crimping of the crimped sheet of homogenized tobacco material to form a rod. However, it should be understood that the crimped sheet of homogenized 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. something to do. In certain embodiments, sheets of homogenized 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 homogenized tobacco material for use in the manufacture of a rod for use in an aerosol-generating article according to the present invention may comprise a plurality of substantially parallel spaced apart substantially uniformly across the width of the sheet. May include ridges or wavy lines.

The sheet or web of homogenized 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 homogenized 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 the agglomeration of particulate tobacco. have. Alternatively, or in addition, sheets of homogenized tobacco material for use in the aerosol-generating substrate include, but are not limited to, tobacco and non-tobacco fibers, aerosol formers, wetting agents, plasticizers, flavoring agents, fillers, aqueous and other additives including non-aqueous solvents, and combinations thereof.

Suitable external binders for incorporation into sheets or webs of homogenized 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 homogenized tobacco material for use in aerosol-generating substrates are known in the art and include cellulosic fibers; soft wood fibers; hard wood fibers; including, but not limited to, jute fibers and combinations of the two. Prior to inclusion in a sheet of homogenized tobacco material for use in an aerosol-generating substrate, non-tobacco fibers may be subjected to, but not limited to, mechanical pulping; refining; chemical pulping; bleaching; sulfate pulping; and combinations thereof.

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

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

The sheet of homogenized 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 homogenized tobacco material has an aerosol former content of less than 25% on a dry weight basis.

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

Sheets or webs of homogenized 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 homogenized tobacco material for use in an aerosol-generating article is formed by a casting process into a slurry comprising particulate tobacco, guar gum, cellulose fibers and glycerin.

Alternative arrangements of homogenized tobacco material in rods for use in aerosol-generating articles will be known to those skilled in the art and include a plurality of stacked sheets of homogenized tobacco material, winding a strip of homogenized tobacco material around their longitudinal axes. It may include a plurality of elongate tubular elements and the like formed by doing so.

As a further alternative, the rod of the aerosol-generating substrate may comprise a non-tobacco-based, nicotine-containing material, such as a sheet of sorbent 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 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. By way of example, the mouthpiece may include a hollow tube arranged in alignment longitudinally and immediately downstream with a 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 some preferred embodiments, 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. Indeed, the hollow tubular segment provides a chamber for the accumulation and flow of the volatilized aerosol component released upon heating the aerosol-generating substrate. As briefly described above, this chamber extends completely longitudinally 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 so that it can be easily handled by the consumer and inserted into the aerosol-generating device for use. On the other hand, it is preferred that the overall volume of the chamber internally defined 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 this requirement, as briefly mentioned above, the thickness of the peripheral wall of the hollow tubular segment is less than 1.5 mm. Preferably, the thickness of the peripheral wall of the hollow tubular segment is less than 1250 μm, more preferably less than 1000 μm, even more 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.

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

Preferably, the equivalent inner diameter of the hollow tubular segment is at least about 4 mm. The term "equivalent inner diameter" is used herein to denote the diameter of a circle having the same surface area of the cross-section of an airflow conduit defined internally by a 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 such a case, the equivalent inner diameter of the hollow tubular segment effectively coincides with the inner diameter of the cylindrical tube.

In a preferred embodiment, the equivalent inner diameter of the hollow tubular segment is at least about 5 mm, more preferably 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 above-mentioned range can provide aerosol delivery of particularly satisfactory 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 foregoing range is such that an inlet stream of cooler ventilation air flows at a relatively low velocity when received into and mixed with the aerosol stream. is assumed to be As the aerosol stream advances relatively slowly along the hollow tubular segment, the beneficial effect of cooling on aerosol nucleation is expected to be maximized under these conditions.

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 an exemplary embodiment, 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 mouthpiece segments has a basis weight of at least about 80 gsm, more preferably at least about 90 gsm. In a particularly preferred embodiment, the combination wrapper connecting the rod and mouthpiece segments has a basis weight of at least about 110 gsm, more preferably at least about 130 gsm. 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.

As an example, the hollow tubular segment may comprise a tube formed from an extruded plastic tube. Alternatively, the hollow tubular segment may comprise a tube formed of 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 a plurality of overlapping paper layers may help further improve resistance to denting 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 can be made air impermeable by 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 together with an adhesive that imparts sealing properties to the tube.

Materials suitable for forming the tube are known in the art and include, but are not limited to, cellulose acetate, rigid paper (i.e., paper having a basis weight of at least 90 gsm), polymeric films such as cellulosic films, and paperboard. .

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. 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 0.5. 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, and is formed of a wrapper having a weight of 2.5 mg/mm and a basis weight of 110 gsm. 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 may be provided as a cellulose acetate tube having an internal equivalent diameter of 5.3 mm and 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.

As briefly described above, an aerosol-generating article according to the present invention comprises a ventilation zone at a location along the hollow tubular segment 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.

A ventilation zone may be provided at a location along a hollow tubular segment of at least 2 mm from the upstream end of the mouthpiece. Preferably, the ventilation zone is provided at a location along a hollow tubular segment of at least 4 mm from the upstream end of the mouthpiece. Preferably, the ventilation zone is provided at a location along a hollow tubular segment of at least 5 mm from the upstream end of the mouthpiece. Even more preferably, the ventilation zone is provided at a location along a hollow tubular segment of at least 6 mm from the upstream end of the mouthpiece.

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 in the ventilation zone is less than 2, more preferably less than 1.5, even more preferably less than 1.2 am.

As the mixture of aerosol particles and air flowing through the aerosol-generating article reaches the ventilation zone, the 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.

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

Additionally or alternatively, the ventilation zone is preferably at a location along a hollow tubular segment of less than 25 mm from the downstream end of the mouthpiece segment. More preferably, the ventilation zone is at a location along the hollow tubular segment less than 20 mm from the downstream end of the mouthpiece segment. This is effectively such that, during use, when the aerosol-generating article is received within the heating chamber of an electrically heated aerosol-generating device, the ventilation zone is positioned along the hollow tubular segment protruding outward of the heating chamber, such that external cooling air can easily enter the hollow tubular segment. Ensure that it can be aspirated.

In some preferred embodiments, the ventilation zone is located 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 along the hollow tubular segment 18 mm from the downstream end of the mouthpiece segment. In another exemplary embodiment, the ventilation zone is provided at a location along the hollow tubular segment 13 mm from the downstream end of the mouthpiece segment.

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

In preferred embodiments, the aerosol-generating article has a ventilation level of at least about 20% or 25% or 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% or less than about 40%. In a particularly preferred embodiment, the aerosol-generating article has a ventilation level of from about 25% to about 60%. More preferably, the aerosol-generating article has a ventilation level of from about 28% to about 42%. In some particularly preferred embodiments, the aerosol-generating article has a ventilation level of about 35%.

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 depends on coalescence, as well as the delicate interactions between nucleation, evaporation, and condensation, which account for changes in vapor concentration, temperature, and velocity fields throughout. . The so-called classical nucleation theory is based on the assumption that some of the gaseous molecules are large enough to remain cohesive for a long time with sufficient probability (eg, half probability). These molecules represent some kind of important critical molecular clusters among transient molecular aggregates, suggesting that, on average, smaller molecular clusters are more likely to disintegrate into the gas phase rather quickly, while larger clusters are 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 pure droplets with only nuclei can emerge to a certain original diameter and then grow by several orders of magnitude. This is facilitated and can be 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. Evaporation relates to the net mass transfer from a liquid droplet to the gas phase, whereas condensation is a net mass transfer from the gas phase to the droplet phase. Evaporation (or condensation) will shrink (or grow) the droplets, but will not change the number of droplets.

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 usually non-linear, different cooling rates can result in significantly different temporal behaviors, such as those with respect to the formation of liquid phases (droplets). Without wishing to be bound by theory, it is hypothesized that cooling may cause a rapid increase in the number concentration of the droplet, followed by a strong and short-term increase in this growth (nucleation rupture). These nucleation ruptures will appear to be more significant at lower temperatures. It would also appear that higher cooling rates may favor earlier 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 when the ventilation level is between 30% and 50%, the dilution effect on the aerosol - in particular can be evaluated by measuring the effect on the delivery of glycerin comprised in an aerosol-generating substrate as an aerosol former - is advantageously minimized found to be In particular, it has been found that ventilation levels of 35% to 42% lead to particularly satisfactory values of glycerin delivery. At the same time, the degree of nucleation and, consequently, the delivery of nicotine and aerosol formers (eg glycerol) are improved.

Furthermore, the inventors have found that, in an aerosol-generating article according to the invention, the cooling and diluting effect caused by introducing ventilation air at a location along the conduit defined by the aforementioned hollow tubular segment is a surprising reduction in the generation and transmission of phenol-containing species. found to have an 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. This is understood to be advantageous in that it may be possible to further enhance aerosol nucleation 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, adjacent rows of perforations may be longitudinally spaced from one another 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 of 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 be of 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 can be performed using any suitable technique, for example laser technology, mechanical perforation of a hollow tubular segment as part of an aerosol-generating article, or a hollow tubular segment before combining with other elements to form an aerosol-generating article, for example. It can be formed by pre-drilling of Preferably, the ventilation perforation is formed by online laser perforation.

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, as the hollow tubular segment is substantially empty and, as such, contributes substantially only to the overall RTD. In practice, hollow tubular segments can be adapted to generate RTDs ranging _{from approximately 0 mmH 2} O (about 0 Pa) to approximately 20 mmH _{2 O (about 200 Pa).} Preferably, the hollow tubular segment is _{adapted to generate an RTD of about 0 mmH 2} O (about 0 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 mmH 2} O (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 about 7 mm.

In some embodiments, an aerosol-generating article according to the present invention may comprise an additional support element arranged longitudinally and arranged between the rod of the aerosol-generating substrate and the hollow tubular segment. 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 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 about 5 mm and 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 device. may be requested. This may damage one or both of the aerosol-generating article or the heating element of the aerosol-generating device. Further, 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 cause the heating element of the aerosol-generating device to be 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 internally defined 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. The furnace divides into longitudinally extending downstream sub-cavities. Without wishing to be bound by theory, it is stated that in the upstream sub-cavity, 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, slowly cooling 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 5 or less than 3 or 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 1.2 or less than 1. 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 advantageous to possibly reduce 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 aerosol-generating articles The difference between the RTDs of the aerosol-generating article having the lowest RTD of the 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 less than 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) or 6 mmH ₂ O (about 60 Pa) or less than 5 mmH ₂ O (about 50 Pa) or 4 mmH ₂ O (about 40 Pa) or 3 mmH ₂ O (about 30 Pa) or 2 mmH ₂ O (about 20 Pa).

In the following the invention will be further described with reference to the accompanying drawings in which:
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 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 located 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 corrugated sheet of homogenized tobacco material. The homogenized sheet of tobacco material comprises 10% by weight on a dry 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 14 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, paper having a basis weight of 110 gsm, and has a weight of 45 mg (ie, 2.5 mg/mm length). The equivalent inner diameter of the hollow tubular segment 16 is about 7 mm. Thus, the volume of the cavity defined internally 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 construction as the aerosol-generating article 10 of FIG. 1 , differs from the aerosol-generating article 10 only in substantially certain component lengths, and differs from the aerosol-generating article 10 with the aerosol-generating article 10 . will be explained only below unless different. Hereinafter, in all possible cases, the same reference numerals will be used 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 is, for example, cellulose having a length of about 18 mm and a peripheral wall thickness of about 1 mm, with a weight of 171 mg (ie, 9.5 mg/mm length). It can be provided as a cylindrical tube of acetate.

The equivalent inner diameter of the hollow tubular segment 16 may be about 5.3 mm. Thus, the volume of the cavity defined internally 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. Thus, the lengths of the three main components are also different. Hereinafter, in all possible cases, the same reference numerals will be used 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. and a plug of cellulose acetate tow having a length of 11 denier per filament. The 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 examples below record experimental results obtained during tests performed on specific embodiments of aerosol-generating articles according to the 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 provided at a location where a ventilation zone follows the hollow tubular segment according to the present invention. The experiment investigated the effect of ventilation levels on the delivery of nicotine and an aerosol former (glycerin). Comparative measurements with reference aerosol-generating articles without ventilation are also provided.

Materials and Methods

Article A is a corrugated sheet of homogenized tobacco material and a rod of an aerosol-generating substrate comprising about 18% by dry weight of glycerin by dry weight, the rod having a length of 12 mm; A support element in the form of a hollow cellulose acetate tube aligned with a rod 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; A mouthpiece segment of filtration material aligned with and immediately downstream of the hollow tubular segment, an aerosol-generating article formed from a mouthpiece segment having a length of 12 mm. 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 level of ventilation of the aerosol-generating article A is 30%.

Article B is a reference aerosol-generating article having the same construction as article A but without a ventilation zone. Thus, the level of ventilation 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) on 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 presented in Table 1 below.

Effects of ventilation levels on nicotine and glycerin delivery. Ventilation nicotine delivery glycerin [%] [mg] [mg] Item A 30 1.41 5.6 Item B 0 1.17 3.5

Claims (14)

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, the mouthpiece segment arranged downstream of the rod and longitudinally aligned with the rod; and
a hollow tubular segment positioned between the rod and the mouthpiece segment, wherein the hollow tubular segment is longitudinally aligned with the rod and the mouthpiece segment, the hollow tubular segment extending completely to the upstream end of the mouthpiece segment. a hollow tubular segment defining an extending cavity;
a ventilation zone at a location along the hollow tubular segment less than about 18 mm from the upstream end of the hollow tubular segment;
the thickness of the peripheral wall of the hollow tubular segment is less than about 1.5 mm;
the rod of aerosol-generating substrate comprises at least an aerosol former, wherein the rod of the aerosol-generating substrate has an aerosol former content of at least about 10% by dry weight;
The aerosol-generating article has a ventilation level of at least about 10%. The aerosol-generating article of claim 1 , wherein the hollow tubular segment comprises a wrapper, the wrapper also surrounding the rod and the mouthpiece segment. The aerosol-generating aerosol-generating segment 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, the tube and the mouthpiece segment. article. 4 . The aerosol-generating article according to claim 1 , wherein the ventilation zone is located along the hollow tubular segment at least 2 mm from the upstream end of the mouthpiece segment. 5. The aerosol-generating article of claim 4, wherein the ventilation zone is at a location along a hollow tubular segment less than 25 mm from the downstream end of the mouthpiece segment. 6. The aerosol-generating article according to any one of the preceding claims, wherein the aerosol-generating article has a ventilation level of less than about 60%. 7. The aerosol-generating article according to any one of the preceding claims, wherein the rod has a length of less than about 15 mm. 8. The aerosol-generating article according to any one of claims 1 to 7, wherein the hollow tubular segment has a length of from about 10 mm to about 30 mm. 9. The aerosol-generating article according to any one of claims 1 to 8, wherein the overall length of the aerosol-generating article is from about 40 mm to about 70 mm. 10 . The aerosol-generating article according to claim 1 , wherein the hollow tubular segment has a thickness of at least about 100 μm. 11. The aerosol-generating article according to any one of the preceding claims, wherein the inner equivalent diameter of the hollow tubular segment at the location of the ventilation zone is at least about 4 mm. 12. The aerosol-generating article according to any one of claims 1 to 11, wherein the RTD of the aerosol-generating article is from about 30 mmH ₂ O to about 90 mmH ₂ O. 13. The aerosol-generating article according to any one of the preceding claims, wherein the vents comprise a single row of apertures formed through the peripheral wall of the hollow tubular segment. 14. A pack comprising at least 10 aerosol-generating articles according to any one of the preceding claims, wherein the RTD of the aerosol-generating article having the highest RTD of the at least 10 aerosol-generating articles and the at least 10 aerosol-generating articles The difference between the RTDs of the aerosol-generating article having the lowest RTD of the article is less than _{10 mmH 2 O.}

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