JP7373388B2 - Aerosol-generating article with aerated hollow segments - Google Patents

Description

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

Aerosol-generating articles in which an aerosol-generating substrate, such as a tobacco-containing substrate, is heated rather than combusted are well known in the art. Typically, in such heated smoking articles, the aerosol is in contact with the heat source and onto a physically separated aerosol-generating substrate or material that may be located in, around, or downstream from the heat source. , produced by transferring heat from a heat source. During use of the aerosol-generating article, volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source and become entrained in the air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol.

Numerous prior art documents disclose aerosol generating devices for consuming aerosol generating articles. For example, such devices include electrically heated aerosol generators in which an aerosol is generated by heat transfer from one or more electrical heating elements of the aerosol generator to an aerosol-forming substrate of a heated aerosol-generating article.

Substrates for heated aerosol generating articles have heretofore been generally manufactured using randomly oriented pieces, strands, or strips of tobacco material. Alternatively, rods for heated aerosol-generating articles formed from a collection of sheets of tobacco material have been proposed, for example, in international patent application WO-A-2012/164009. The rod disclosed in WO 2012/164009 has a longitudinal porosity that allows air to be drawn through the rod. In effect, the folds within the assembly of sheets of tobacco material define longitudinal channels through the rod.

Alternative rods for heated aerosol generating articles are known from international patent application WO-A-2011/101164. These rods are formed from strands of homogenized tobacco material, and a mixture containing particulate tobacco and at least one aerosol former is cast, rolled, calendered, or extruded to form a sheet of homogenized tobacco material. It can be formed by In an alternative embodiment, the rod of WO-A-2011/101164 also extrudes a mixture comprising particulate tobacco and at least one aerosol former to form a continuous length of homogenized tobacco material. It may be formed from strands of homogenized tobacco material obtained by forming.

Substrates for heated aerosol-generating articles typically include an aerosol former, i.e., a compound or compounds that facilitate the formation of an aerosol during use and are preferably substantially resistant to thermal decomposition at the temperatures of use of the aerosol-generating article. further comprising a mixture of. 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, may be mentioned.

It is also common to include within the aerosol-generating article one or more additional elements assembled with the substrate within the same wrapper to generate an inhalable aerosol upon heating. Examples of such additional elements include mouthpiece filtration segments, support elements adapted to provide structural strength to the aerosol-generating article, and support elements adapted to favor cooling of the aerosol before reaching the mouthpiece. This includes cooling elements, etc. However, the inclusion of such additional elements, while proposed in view of their beneficial effects, generally complicates the overall structure of the aerosol-generating article, making it more complex and expensive to manufacture. In practice, manufacturing such multi-component aerosol-generating articles generally requires more complex manufacturing machinery and combinations of machinery.

In this regard, aerosol generating articles having simpler structures have been proposed. However, in the absence of certain additional components, such as, for example, aerosol cooling elements, it can be 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 that is capable of consistently providing a consumer with satisfactory aerosol delivery during use. Additionally, it would be desirable to provide improved aerosol generating articles having such satisfactory RTD values. It would also be desirable to provide such aerosol-generating articles that are manufactured efficiently and rapidly, preferably with low RTD variation from article to article. The present invention aims to provide a technical solution adapted to achieve at least one of the above-mentioned desired results.

According to one aspect of the invention, an aerosol-generating article for producing an inhalable aerosol upon heating is provided, the aerosol-generating article comprising:
a rod of aerosol-generating substrate, a mouthpiece segment comprising a plug of filtration material and disposed downstream of the rod and longitudinally aligned with the first segment; and a mouthpiece segment positioned between the rod and the mouthpiece segment. and a hollow tubular segment. The hollow tube segment is longitudinally aligned with the rod and mouthpiece segment. Furthermore, the hollow tubular segment defines a recess that extends all the way to the upstream end of the mouthpiece segment. The aerosol generating article further includes a ventilation zone located along the hollow tubular segment. The equivalent internal diameter of the hollow tubular segment at the location of the ventilation zone is at least about 5 millimeters. The rod of aerosol-generating substrate includes at least an aerosol former, and the rod of aerosol-generating substrate has an aerosol former content of at least about 10 percent on a dry mass basis.

The term "aerosol-generating article" as used herein refers to an article in which an aerosol-generating substrate is heated to produce an inhalable aerosol for delivery to a consumer. As used herein, the term "aerosol-generating substrate" refers to a substrate that has the ability to release volatile compounds upon heating to generate an aerosol.

Traditional cigarettes are ignited when a user attaches a flame to one end of the cigarette and breathes air through the other end. The localized heat provided by the flame and the oxygen in the air drawn through the cigarette ignites the end of the cigarette, 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 a cigarette). Known heated aerosol generating articles include, for example, electrically heated aerosol generating articles and aerosol generating articles in which an aerosol is produced by the transfer of heat from a combustible fuel element or heat source to a physically separated aerosol forming material. Examples include goods. For example, an aerosol generating article according to the present invention has particular application as an aerosol generating system comprising an electrically heated aerosol generator 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 European Patent No. EP0822670.

As used herein, the term "aerosol generating device" refers to a device that includes a heater that interacts with an aerosol generating substrate of an aerosol generating article to generate an aerosol.

The term "tubular segment" is used herein to mean an elongated element that defines a lumen or airflow passageway along its longitudinal axis. In particular, the term "tubular" hereinafter refers to at least one airflow conduit having a substantially cylindrical cross-section and establishing uninterrupted fluid communication between the upstream end of the tubular element and the downstream end of the tubular element. used for tubular elements that define a However, it will be appreciated that alternative geometries of the cross-section of the tubular element may also be possible.

As used herein, the term "longitudinal" refers to a direction corresponding to the main longitudinal axis of the aerosol-generating article, extending between the upstream and downstream ends of the aerosol-generating article. The terms "upstream" and "downstream" as used herein refer to the relative position of an element (or portion of an element) of an aerosol-generating article with respect to the direction in which aerosol is conveyed through the aerosol-generating article during use. Describe.

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

The term "length" refers to the dimension of a component of an aerosol generating article in the longitudinal direction. For example, it can be used to refer to the longitudinal dimension of a rod or elongated tubular element.

The term "peripheral wall thickness of a tubular element" is used herein to mean the minimum distance measured between the outer and inner surfaces of the wall bounding the periphery of the tubular element. In practice, the distance at a given location is measured along a direction that is locally substantially perpendicular to the outer and inner surfaces of the tubular element. For tubular elements having a substantially circular cross-section, the distance is measured along a substantially radial direction of the tubular element.

In some embodiments, the peripheral wall of the tubular element has a constant thickness. 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 from 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, the "thickness of the peripheral wall of the tubular element" refers to the outer surface of the wall at different locations along the length of the tubular element. and the inner surface is considered an average value calculated on the basis of several measured values.

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

The expression "air-impermeable material" throughout this specification refers to a material that does not allow the passage of fluids, especially air and smoke, through the interstices and pores of the material. If the hollow tubular segment is formed of a material that is impermeable to air and aerosol particles, the air and aerosol particles drawn through the hollow tubular segment are forced to be internally defined by the hollow tubular segment. airflow conduit, but cannot flow across the peripheral walls of the hollow tubular segment.

As used herein, the term "homogenized tobacco material" includes any tobacco material formed by agglomeration of particles of tobacco material. A sheet or web of homogenized tobacco material is formed by agglomerating particulate tobacco obtained by grinding or otherwise pulverizing tobacco leaf lamina and/or tobacco stalks. be done. Additionally, the homogenized tobacco material may include one or more of small amounts of tobacco dust, tobacco fines, and other particulate tobacco by-products formed during tobacco processing, handling, and shipping. Sheets of homogenized tobacco material may be manufactured by casting, extrusion, papermaking processes, or any other suitable process known in the art.

The term "porous" as used herein refers to a material that provides a plurality of pores or openings that allow the passage of air through the material.

The term "ventilation level" is used throughout this specification to mean the volumetric ratio of the airflow that enters the aerosol-generating article through the ventilation zone (ventilation airflow) and the sum of the aerosol airflow and the ventilation airflow. used. The greater the ventilation level, the greater the dilution of the aerosol stream delivered to the consumer.

As briefly mentioned above, the aerosol-generating article of the present invention comprises a rod of an aerosol-generating substrate, a mouthpiece segment including a plug of filtration material, and a hollow tubular segment located between the rod and the mouthpiece segment. Be prepared. These three elements are longitudinally aligned. The rod of the aerosol generating substrate includes at least one aerosol former.

In contrast to known aerosol generating articles, the rod of aerosol generating substrate has an aerosol former content of at least about 10 percent on a dry mass basis. Furthermore, the hollow tubular segment defines a recess extending all the way to the upstream end of the mouthpiece segment, and a ventilation zone is provided at a location along the hollow tubular segment. Additionally, the equivalent inner diameter of the hollow tube segment is at least about 5 millimeters.

the overall structure of the article by providing an aerosol-generating article in which a hollow tubular element defining a recess extending all the way to the upstream end of the mouthpiece segment is disposed between the rod of the aerosol-generating substrate and the mouthpiece; The physical complexity can be significantly reduced compared to existing aerosol generating articles. This advantageously simplifies the manufacturing process and reduces the complexity of manufacturing and assembling the equipment necessary to carry out the manufacturing process.

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

The inventors have demonstrated that satisfactory cooling of the aerosol flow generated during heating of the article and drawn through the hollow tubular element is achieved by providing ventilation zones at locations along the hollow tubular segment. I found out. Additionally, the inventors have surprisingly discovered that by utilizing hollow tubular segments having a significant internal diameter of at least about 5 millimeters, the inventors have offset the effects of increased aerosol dilution caused by admitting circulating air into the article. We have found that this may be possible.

Without being bound by theory, it is believed that the introduction of flowing air rapidly reduces the temperature of the aerosol stream as the aerosol moves toward the mouthpiece segment, so that the introduction of flowing air rapidly reduces the temperature of the aerosol stream as it moves toward the mouthpiece segment. (i.e., sufficiently close to the heat source and rods of the aerosol-generating substrate), dramatic cooling of the aerosol stream is achieved, which favorably influences condensation and nucleation of aerosol particles. It is considered to have. Accordingly, the overall ratio of aerosol particle phase to aerosol gas phase may be improved compared to existing non-ventilated aerosol generating articles.

At the same time, by utilizing a hollow tubular element with an equivalent internal diameter of 5 mm or more, the hollow tubular element is available for the aerosol to begin the nucleation process as soon as the aerosol component leaves the rod of the aerosol-generating substrate. This ensures that the overall internal volume of the tubular element and the cross-sectional surface area of the hollow tubular segment are effectively maximized, while at the same time the hollow tubular segment prevents disintegration of the aerosol-generating article. This also ensures that it has the necessary structural strength to provide some degree of support to the rods of the aerosol generating substrate and that the RTD of the hollow tubular segment is minimized. It is understood that a large value of the cross-sectional surface area of the depressions of the hollow tubular segment is associated with a reduced velocity of the aerosol stream traveling along the aerosol-generating article, further favoring nucleation. In fact, without being bound by theory, by providing a recess with such a large volume, as in the case of the article according to the invention, the nucleation phenomenon can be induced within it by slowing down the flow of the aerosol stream. The improved attenuation effectively provides a cooling chamber that can favor condensation of aerosol particles upstream of the mouth end of the article.

It is understood that providing a sufficiently wide tubular recess downstream of the rod of the aerosol-generating substrate favors a sufficient amount of aerosol formation during use. As a result, a greater proportion of the aerosol particles produced begin to condense before reaching the mouth end of the article.

In fact, the inventors surprisingly discovered how the beneficial effects of enhanced nucleation can be diluted so that satisfactory values of aerosol delivery are consistently achieved with aerosol-generating articles according to the invention. We found that this significantly offsets the undesirable effects of This may mean that the rod length 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 about 60 mm. It is particularly advantageous for "short" aerosol generating articles, such as those less than a millimeter, and even more preferably less than 50 millimeters. As will be appreciated, such aerosol generating articles have less time and space for aerosol formation and for the particulate phase of the aerosol to be available for delivery to the consumer.

Furthermore, since the hollow tubular elements do not substantially contribute to the RTD of the aerosol-generating article, the length and density of the rods of the aerosol-generating substrate or the length of the segments of the filtration material of the mouthpiece are By adjusting the thickness and density, the overall RTD of the article can be advantageously fine-tuned. This makes it possible to consistently and highly accurately manufacture aerosol-generating substrates with a predetermined RTD, such that even in the presence of ventilation, a satisfactory level of RTD can be provided to the consumer. .

Aerosol-generating articles according to the present invention can be manufactured in a continuous process that is fast and efficiently run, without requiring extensive modification of manufacturing equipment, and existing production lines for the manufacture of heated aerosol-generating articles. can be easily manufactured.

Preferably, the rod of the aerosol-generating substrate 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 millimeters. The rod of the aerosol generating substrate can have an outer diameter of about 5 mm to about 12 mm, such as about 5 mm to about 10 mm, or about 6 mm to about 8 mm. In one preferred embodiment, the rod of the aerosol generating substrate has an outer diameter of 7.2 millimeters ± 10 percent.

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

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

In a preferred embodiment, the aerosol-forming substrate comprises a collection of one or more crimped sheets of homogenized tobacco material. Preferably, the one or more sheets of homogenized tobacco material are textured. As used herein, the term "textured sheet" means a sheet that has been crimped, embossed, debossed, perforated, or otherwise modified. Textured sheets of homogenized tobacco material for use in the present invention may include a plurality of spaced indentations, protrusions, perforations or combinations thereof. According to a particularly preferred embodiment of the invention, the rod of the aerosol-generating substrate comprises a collection of crimped sheets of homogenized tobacco material surrounded by a wrapper.

As used herein, the term "crimped sheet" is intended to be substantially synonymous with the term "crimped sheet" and includes a plurality of substantially parallel ridges or undulating shapes. means a sheet with . 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 assembly of crimped sheets of homogenized tobacco material to form rods. However, it will be appreciated that the crimped sheet of homogenized tobacco material for use in the present invention may alternatively or additionally include a plurality of crimped sheets at acute or obtuse angles to the cylindrical axis of the rod. Having a substantially parallel ridge or wavy shape. In certain embodiments, a homogenized sheet of tobacco material for use in a rod of an article of the present invention can be textured substantially evenly over substantially its entire surface. For example, a crimped sheet of homogenized tobacco material for use in making a rod for use in an aerosol-generating article according to the present invention may include a plurality of crimped sheets of homogenized tobacco material substantially uniformly spaced across the width of the sheet. may include parallel ridges or wavy shapes.

A sheet or web of homogenized tobacco material for use in the present invention may have a tobacco content of at least about 40 weight percent on a dry weight basis, and at least about 60 weight percent tobacco on a dry weight basis. More preferably, the tobacco content has a tobacco content of at least about 70 weight percent on a dry weight basis, and most preferably a tobacco content of at least about 90 weight percent on a dry weight basis.

A sheet or web of homogenized tobacco material for use in an aerosol-generating substrate comprises one or more inherent binders, which are tobacco-intrinsic binders, to assist in agglomerating the particulate tobacco; It may include one or more exogenous binding agents that are tobacco exogenous binding agents, or combinations thereof. Alternatively, or in addition, sheets of homogenized tobacco material for use in an aerosol-generating substrate include tobacco and non-tobacco fibers, aerosol formers, wetting agents, plasticizers, flavoring agents, fillers, aqueous and other additives including, but not limited to, non-aqueous solvents and combinations thereof.

Suitable extrinsic binders for inclusions in sheets or webs of homogenized tobacco material for use in aerosol-generating substrates are well known in the art and include gums such as guar gum, xanthan gum, gum arabic and locust. Conjugation of cellulose binders such as bean gum, e.g. hydroxypropylcellulose, carboxymethylcellulose, hydroxyethylcellulose, methylcellulose and ethylcellulose, polysaccharides, e.g. starch, organic acids such as alginic acid, sodium alginate, agar and pectin. base salts, etc., and combinations thereof.

Suitable non-tobacco fibers for inclusion in sheets or webs of homogenized tobacco material for use in aerosol-generating substrates are well known in the art and include cellulose fibers, soft wood fibers, hard wood fibers, jute fibers and the like. including, but not limited to, combinations of. Prior to inclusion in a sheet of homogenized tobacco material for use in an aerosol-generating substrate, the non-tobacco fibers may be processed by any suitable process known in the art, including mechanical pulping; refining; including, but not limited to, 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" means any suitable material that, in use, facilitates the formation of an aerosol and is substantially resistant to thermal decomposition at the temperature of use of the aerosol-generating article. Describe a well-known compound or mixture of compounds.

Suitable aerosol formers are known in the art: polyhydric alcohols such as propylene glycol, triethylene glycol, 1,3-butylene glycol and glycerin; esters; and aliphatic esters of mono-, di- or polycarboxylic acids such as dimethyldodecanedioate and dimethyltetradecanedioate.

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

A sheet or web of homogenized tobacco material may contain a single aerosol former. Alternatively, the sheet or web of homogenized tobacco material may include 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 percent on a dry weight basis. Preferably, the sheet or web of homogenized tobacco material has an aerosol former content of greater than 12 percent on a dry weight basis. More preferably, the sheet or web of homogenized tobacco material has an aerosol former content of greater than 14 percent 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 percent on a dry weight basis.

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

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

Homogenized tobacco sheets or webs for use in the aerosol-generating articles of the present invention may be manufactured by methods well known in the art, such as those disclosed in International Patent Application No. WO 2012/164009A2. . In a preferred embodiment, a sheet of homogenized tobacco material for use in an aerosol-generating article is formed from a slurry comprising particulate tobacco, guar gum, cellulose fibers, and glycerin by a casting process.

Alternative arrangements of homogenized tobacco material within a rod for use in aerosol-generating articles are well known to those skilled in the art and include multiple stacked sheets of homogenized tobacco material, with the longitudinal axis It may include a plurality of elongate tubular elements formed by winding strips of homogenized tobacco material therearound, or the like.

As a further alternative, the rod of aerosol-generating substrate may include a non-tobacco-based nicotine-containing material, such as a sheet of absorbent non-tobacco material formulated 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 aerosol-generating substrate may include non-tobacco plant material, such as aromatic non-tobacco plant material.

In the rod of aerosol-generating substrate of the article according to the invention, it is preferred that the aerosol-generating substrate is surrounded by a wrapper. The wrapper may be formed of 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 that can remove particulate components, gaseous components, or a combination. Suitable filtration materials are well known in the art and include, for example, fibrous filtration materials such as cellulose acetate tow, viscose fibres, polyhydroxyalkanoic acid (PHA) fibres, polylactic acid (PLA) fibres, and papers such as activated Adsorbents such as, but not limited to, alumina, zeolites, molecular sieves and silica gel, and combinations thereof. Additionally, the plug of filtration material may further include one or more aerosol modifiers. Suitable aerosol modifiers are well known in the art and include, but are not limited to, for example, flavoring agents such as menthol. In some embodiments, the mouthpiece can further include a mouth end depression downstream of the plug of filtering material. By way of example, the mouthpiece may include a hollow tube longitudinally aligned with and positioned immediately downstream of the plug of filtration material, the hollow tube at the downstream end of the mouthpiece. Forms a depression at the oral end, open to the external environment.

Preferably, the length of the mouthpiece is at least about 4 mm, more preferably at least about 6 mm, and 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, and even more preferably less than 15 mm. In some preferred embodiments, the length of the mouthpiece is about 4 mm to about 25 mm, more preferably about 6 mm to about 20 mm. In an exemplary embodiment, the length of the mouthpiece is approximately 7 millimeters. In another exemplary embodiment, the length of the mouthpiece is about 12 millimeters.

Preferably, the hollow tubular segment is an annular tube that partitions and defines an air gap within the aerosol generating article. In effect, the hollow tubular segment provides a chamber into which the volatilized aerosol constituents released upon heating of the aerosol-generating substrate accumulate and flow. As briefly mentioned above, this chamber extends longitudinally entirely 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, it This means that the flowing aerosol also reaches substantially the upstream end of the mouthpiece. More particularly, aerosol flowing through the aerosol-generating article generally reaches the upstream end of a segment of filtering material in the mouthpiece.

Thus, in an aerosol-generating article according to the invention, the hollow tubular segment maintains the rod of the aerosol-generating substrate at a predetermined distance from the mouthpiece and provides an elongated airflow conduit for forming and channeling the aerosol toward the mouthpiece. . During use, a thermal gradient is established along this airflow conduit. In practice, the temperature difference is such that the temperature of the volatilized aerosol components entering the hollow tubular segment at the upstream end is higher than that of the volatilized aerosol components exiting the hollow tubular segment at the downstream end (i.e., the upstream end of the mouthpiece). Provided, so as to be greater than the temperature.

On the other hand, the hollow tubular segment must withstand any axial compressive loads or bending moments that may be applied to the hollow tubular segment during manufacture of the aerosol generating article. Furthermore, the hollow tubular segment should provide 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 desirable that the overall volume of the chamber internally defined by the hollow tubular element be as large as possible, so as to favor the formation of the aerosol and improve the delivery of the aerosol to the consumer.

To meet these requirements, as briefly discussed above, the equivalent inner diameter of the hollow tubular segment is at least about 5 millimeters. The term "equivalent inner diameter" as used herein means the diameter of a circle that has the same surface area as the cross-section of the airflow conduit internally defined 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, ie the hollow tubular segment is a substantially cylindrical tube. In that case, the equivalent internal diameter of the hollow tubular segment essentially corresponds to the internal diameter of the cylindrical tube.

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

Further, it is preferred that the equivalent inner diameter of the hollow tubular segment is less than about 10 millimeters. More preferably, the equivalent inner diameter of the hollow tubular segment is less than about 9.5 millimeters, and even more preferably less than 9 millimeters.

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

In preferred embodiments, 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.

Surprisingly, the inventors have discovered that an aerosol-generating article according to the invention comprising a hollow tubular segment having a substantial internal diameter within the above-mentioned range may provide particularly satisfactory aerosol delivery values. I found out. Without wishing to be bound by theory, it is believed that an aerosol stream flowing along a hollow tubular segment having a substantial internal diameter within the ranges described above is such that an incoming stream of cooler circulating air is received by the aerosol stream and When mixed, it is believed to flow at a relatively low velocity. Because the aerosol stream moves relatively slowly along the hollow tubular segment, the beneficial cooling effect on aerosol nucleation is expected to be maximized under these conditions.

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

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

Additionally or alternatively, the peripheral wall of the hollow tubular segment has a thickness of at least about 100 micrometers. Preferably, the peripheral wall of the hollow tubular segment has a thickness of at least about 200 micrometers.

Without wishing to be bound by theory, by utilizing a hollow tubular segment having a peripheral wall whose thickness is within the ranges mentioned above, advantageously, prior to its contact with and mixing with the aerosol stream, , it appears possible to limit or even substantially prevent the diffusion of circulating air. This is further understood to favor the nucleation phenomenon. In fact, it is possible to improve the effectiveness of cooling on the formation of new aerosol particles by providing a more controllably localized cooling of the flow of volatile species drawn through hollow tubular segments. .

As briefly discussed above, aerosol generating articles according to the present invention include venting zones at locations along the hollow tubular segment. Preferably, the ventilation zone is provided less than about 18 millimeters 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 millimeters. Even more preferably, the distance between the ventilation zone and the upstream end of the hollow tubular segment is less than about 10 millimeters.

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

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

When the mixture of air and aerosol particles flowing through the aerosol generating article reaches the venting zone, outside air drawn through the venting zone and 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. As will be explained in more detail below, by providing a ventilation zone at a distance from the upstream end of the mouthpiece segment within the aforementioned range, a cooling chamber is effectively provided immediately upstream of the mouthpiece, where can favor nucleation and aerosol particle growth. In this way, the dilution effect of circulating air entering the hollow tubular segment is at least partially offset, which advantageously allows for the provision of a level of aerosol delivery that is satisfactory to the consumer.

In some embodiments, the ratio of the distance between the venting zone and the upstream end of the hollow tubular segment to the equivalent inner diameter of the hollow tubular segment at the location of the venting zone is less than 4. Preferably, the ratio of the distance between the ventilation zone and the upstream end of the hollow tubular segment and the equivalent internal diameter of the hollow tubular segment at the location of the ventilation zone is less than 3.5. More preferably, the ratio of the distance between the ventilation zone and the upstream end of the hollow tubular segment and the equivalent internal diameter of the hollow tubular segment at the location of the ventilation zone is less than 3. Even more preferably, the ratio of the distance between the venting zone and the upstream end of the hollow tubular segment and the equivalent internal diameter of the hollow tubular segment at the location of the venting zone is less than 2.5.

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

Preferably, a ventilation zone is provided along the hollow tubular segment at least 10 millimeters from the downstream end of the mouthpiece segment. More preferably, the ventilation zone is provided along the hollow tubular segment at least 12 millimeters from the downstream end of the mouthpiece segment. Even more preferably, the ventilation zone is provided along the hollow tubular segment at least 15 millimeters from the downstream end of the mouthpiece segment. This is advantageous in ensuring that the ventilation zone is not blocked by the consumer's lips during use.

Additionally or alternatively, the ventilation zone is preferably located less than 25 millimeters along the hollow tubular segment from the downstream end of the mouthpiece segment. More preferably, the ventilation zone is located less than 20 millimeters along the hollow tubular segment from the downstream end of the mouthpiece segment. This is advantageous so that, in use, when the aerosol-generating article is received within the heating chamber of the electrically heated aerosol generator, cold outside air can be easily drawn into the hollow tubular segment. Ensuring that the ventilation zone is effectively located along the hollow tubular segment that projects outside the heating chamber.

In some preferred embodiments, the ventilation zone is 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 10 mm from the downstream end of the mouthpiece segment. Provided at 20 mm position. In an exemplary embodiment, a ventilation zone is provided along the hollow tubular segment 18 millimeters from the downstream end of the mouthpiece segment. In another exemplary embodiment, a ventilation zone is provided along the hollow tubular segment 13 millimeters from the downstream end of the mouthpiece segment.

Aerosol generating articles typically will have a ventilation level of at least about 10 percent, preferably at least about 20 percent.

In preferred embodiments, the aerosol generating article has a ventilation level of at least about 30 percent. More preferably, the aerosol generating article has an air permeability level of at least about 35 percent. Additionally or alternatively, it is preferred that the aerosol generating article have an air permeability level of less than about 60 percent. More preferably, the aerosol generating article has a ventilation level of less than about 50 percent. In particularly preferred embodiments, the aerosol generating article has a ventilation level of about 30 percent to about 60 percent. More preferably, the aerosol generating article has a ventilation level of about 35 percent to about 50 percent. In some particularly preferred embodiments, the aerosol generating article has a ventilation level of about 40 percent.

Without wishing to be bound by theory, the inventors believe that the temperature drop created by admitting cooler outside air through the vent zone into the hollow tubular segment favors the nucleation and growth of aerosol particles. It has been found that this can be effective.

The formation of aerosols from gaseous mixtures containing various chemical species relies on delicate interactions between nucleation, evaporation, and condensation and fusion, accounting for changes in vapor concentration, temperature, and velocity fields. The so-called conventional nucleation theory is based on the assumption that some of the molecules in the gas phase are large enough to remain coherent for long periods of time with sufficient probability (e.g., a probability of 1/2). There is. These molecules represent a type of critical, threshold molecular cluster within a transient molecular aggregate, with smaller molecular clusters generally being more likely to disintegrate into the gas phase fairly quickly and larger clusters generally more likely to grow. It means that it is easy to do. These critical clusters are identified as the main nucleation cores where droplets are expected to grow due to condensation of molecules from the vapor. It is assumed that the freshly nucleated raw droplet emerges with a certain original diameter and can subsequently grow by several sizes. This can be facilitated and enhanced by rapid cooling of the surrounding vapor, inducing condensation. In this regard, it is helpful to keep in mind that evaporation and condensation are two aspects of one and the same mechanism, gas and liquid mass transfer. Evaporation involves a net mass transfer from the droplets to the gas phase, while condensation is the net mass transfer from the gas phase to the droplet phase. Evaporation (or condensation) causes the droplets to shrink (or grow), but the number of droplets does not change.

In this scenario, which may be further complicated by fusion phenomena, the temperature and rate of cooling can play an important role in determining how the system responds. In general, different cooling rates can lead to significantly different temperature behavior with respect to liquid phase (droplet) formation because the nucleation process is generally nonlinear. Without being bound by theory, it is hypothesized that cooling causes a rapid increase in the number of droplet condensations, after which this growth can be strongly increased in a short period of time (burst nucleation). This burst nucleation appears to be more significant at lower temperatures. Furthermore, it appears that high cooling rates may favor early initiation of nucleation. In contrast, reducing the cooling rate appears to have a beneficial effect on the final size that the aerosol droplets ultimately reach.

Therefore, the rapid cooling induced by admitting outside air into the hollow tubular segment through the ventilation zone can be advantageously used to favor the nucleation and growth of aerosol droplets. However, at the same time, admitting outside air into the hollow tubular segment has the direct disadvantage of dilution of the aerosol stream delivered to the consumer.

Surprisingly, the inventors have found that the dilution effect on the aerosol, which can be evaluated in particular by measuring the effect on the delivery of glycerin contained in the aerosol former as an aerosol former, at aeration levels between 30 and 50 per cent. We have found that in some cases it can be advantageously minimized. In particular, aeration levels of 35 percent to 42 percent have been found to lead to particularly satisfactory glycerin delivery values.

Further, the inventors have discovered that in an aerosol-generating article according to the present invention, the cooling and dilution effects produced by the circulating air at locations along the conduit defined by the hollow tubular segments described above have a surprising effect on the production and delivery of phenolic species. It was found that it has 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 includes only one row of perforations. This is understood to be advantageous in that aerosol nucleation can be further improved by condensing the cooling effect provided by the ventilation over a short section of the depression defined by the hollow tube segment. . This is because faster and more dramatic cooling of the stream of volatile species is expected to particularly favor the formation of new nuclei of aerosol particles.

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

Preferably, the equivalent diameter of at least one of the vent perforations is at least about 100 micrometers. Preferably, the equivalent diameter of at least one of the vent perforations is at least about 150 micrometers. Even more preferably, the equivalent diameter of at least one of the vent perforations is at least about 200 micrometers. Additionally or alternatively, the equivalent diameter of at least one of the vent perforations is preferably less than about 500 micrometers. More preferably, the equivalent diameter of at least one of the vent perforations is less than about 450 micrometers. Even more preferably, the equivalent diameter of at least one of the vent perforations is less than about 400 micrometers. The term "equivalent diameter" as used herein means the diameter of a circle that has the same surface area as the cross section of the vent perforation. The cross-section of the ventilation perforations 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 the ventilation perforations, it is possible to adjust the amount of outside air that enters into the hollow tubular segment when the consumer inhales the mouthpiece of the aerosol-generating article during use. Therefore, it is advantageously possible to adjust the ventilation level of the aerosol-generating article.

Vent perforation may be performed using any suitable technique, such as laser technology, mechanical perforation of the hollow tubular segment as part of the aerosol-generating article, or prior to combination with other elements to form the aerosol-generating article. It can be formed using pre-drilling of hollow tubular segments. Preferably, the ventilation perforations are formed by on-line laser drilling.

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

Preferably, the overall length of an aerosol generating article according to the invention is at least about 40 millimeters. Additionally or alternatively, the overall length of an aerosol generating article according to the present invention is preferably less than about 70 millimeters, more preferably less than 60 millimeters, and even more preferably less than 50 millimeters. In preferred embodiments, the overall length of the aerosol generating article is about 40 millimeters to about 70 millimeters. In an exemplary embodiment, the total length of the aerosol generating article is about 45 millimeters.

Preferably, the hollow tubular segment is formed from a substantially impermeable material. Air and aerosol particles drawn through the hollow tubular segment are therefore forced to flow through the hollow tubular segment from its upstream end to its downstream end, but are unable to flow across the peripheral wall of the hollow tubular element.

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

By way of example, the wrapper and mouthpiece segment combination connecting such rods can have a basis weight of at least about 70 grams per square meter (gsm). Preferably, the wrapper and mouthpiece segment combination connecting such rods has a basis weight of at least about 80 grams/square meter, more preferably at least about 90 grams/square meter. In particularly preferred embodiments, the wrapper and mouthpiece segment combination connecting the rods has a basis weight of at least about 110 grams/square meter, more preferably at least about 130 grams/square meter.

In other embodiments, the hollow tubular segment comprises a tube formed from a polymeric or cellulosic material, and the heated aerosol generating article further comprises a wrapper surrounding the rod, tube and mouthpiece segment. As an example, the cellulosic material may include paper or cardboard or mixtures thereof.

As an example, the hollow tubular segment may include a tube formed from an extruded plastic tube. Alternatively, the hollow tubular segment may include a tube formed from multiple overlapping paper layers, such as multiple parallel-wound paper layers or multiple spiral-wound paper layers. Forming the tube from multiple overlapping paper layers may help further improve resistance to collapse or deformation. Preferably, the tube includes two or more paper layers. Alternatively or additionally, it is preferred that the tube comprises fewer than 11 paper layers.

One such tube can be made air impermeable by using substantially air impermeable paper. As used herein, the term "substantially impermeable paper" means an air permeability of less than about 20 Coresta units, more preferably an air permeability of less than about 10 Coresta units, as measured in accordance with ISO 2965:2009. is used to mean paper having an air permeability of less than about 5 Coresta units, most preferably less than about 5 Coresta units. Alternatively, adjacent paper layers within the tube may be held together with an adhesive that provides sealing properties to the tube.

Suitable materials for forming tubes are well known in the art and include cellulose acetate, stiff paper (i.e., paper having a basis weight of at least 90 grams per square meter), polymeric films such as cellulose-based films, and cardboard. including but not limited to.

In some embodiments, the ratio of the weight of the hollow tubular segment to the volume of the internal recess defined by the hollow tubular segment is preferably less than 1 milligram/millimeter. More preferably, the ratio of the weight of the hollow tubular segment to the volume of the internal recess defined by the hollow tubular segment is less than 0.5 milligrams per cubic millimeter.

In particularly preferred embodiments, the ratio of the weight of the hollow tubular segment to the volume of the internal recess defined by the hollow tubular segment is less than 0.25 milligrams/millimeter. More preferably, the ratio of the weight of the hollow tubular segment to the volume of the internal recess defined by the hollow tubular segment is less than 0.2 milligrams per cubic millimeter. Even more preferably, the ratio of the weight of the hollow tubular segment to the volume of the internal recess defined by the hollow tubular segment is less than 0.1 milligrams per cubic millimeter.

In a hollow tubular segment having a ratio of the weight of the hollow tubular segment to the volume of the internal recess defined by the hollow tubular segment that is within the above-mentioned range, the volume of the recess is advantageously maximized, while the volume of the hollow The tubular segment contributes to the overall structural strength of the aerosol-generating article and ensures that the rod of the aerosol-generating substrate is effectively maintained spaced from the mouthpiece.

In an exemplary embodiment, the hollow tubular segment has an equivalent diameter of 7 millimeters, is formed from a wrapper having a basis weight of 110 gsm, and has a weight of 2.5 milligrams/mm. For one such hollow tubular segment, the ratio of the weight of the hollow tubular segment to the volume of the internal recess defined by the hollow tubular segment is about 0.065 milligrams per cubic millimeter.

In another exemplary embodiment, a hollow tubular segment having an equivalent inner diameter of 5.3 millimeters may be provided as a cellulose acetate tube having a weight of 9.5 milligrams/millimetre. For one such hollow tubular segment, the ratio of the weight of the hollow tubular segment to the volume of the internal recess defined by the hollow tubular segment is about 0.43 milligrams per cubic millimeter.

In an aerosol-generating article according to the present invention, the hollow tubular segment is substantially empty and therefore contributes only a substantially small amount to the overall RTD, so that the overall RTD of the article is essentially that of the rod. depending on the RTD of the mouthpiece and the RTD of the mouthpiece. In practice, the hollow tubular segment may be adapted to generate an RTD in the range of approximately 0 mm H ₂ O (approximately 00 Pa) to approximately 20 mm H ₂ O (approximately 200 Pa). Preferably, the hollow tubular segment is adapted to generate an RTD of approximately 0 mm H ₂ O (approximately 00 Pa) to approximately 10 mm H ₂ O (approximately 100 Pa).

Preferably, the aerosol generating article has an overall RTD of less than about 90 millimeters H ₂ O (about 900 Pa). More preferably, the aerosol generating article has an overall RTD of less than about 80 millimeters H ₂ O (about 800 Pa). Even more preferably, the aerosol generating article has an overall RTD of less than about 70 millimeters H ₂ O (about 700 Pa).

Additionally or alternatively, it is preferred that the aerosol generating article have an overall RTD of at least about 30 millimeters H ₂ O (about 300 Pa). More preferably, the aerosol generating article has an overall RTD of at least about 40 millimeters H ₂ O (about 400 Pa). Even more preferably, the aerosol generating article has an overall RTD of at least about 50 millimeters H ₂ O (about 500 Pa).

The RTD of an aerosol-generating article is evaluated as the negative pressure that needs to be applied to the downstream end of the mouthpiece under test conditions defined in ISO 3402 to maintain a stable air flow rate of 17.5 ml/s through the mouthpiece. It can be done. The above RTD values are intended to be measured on the aerosol-generating article itself (i.e. before inserting the article into the aerosol-generating device) without blocking the perforation of the ventilation zone. .

If desired or necessary, for example, the length and density (denier per number of filaments) of the filtration material of the mouthpiece can be adjusted to achieve a sufficiently high RTD of the aerosol-generating article. Additionally or alternatively, additional filter sections may be included in the aerosol-generating article. As an example, such additional filter sections may be included between the rod and the hollow tubular segment of the aerosol-generating substrate. Preferably, such additional filter section comprises a filtration material such as 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 invention comprises an additional support element disposed between and longitudinally aligned with the rod of the aerosol-generating substrate and the hollow tubular segment. sell. 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 from any suitable material or combination of materials. For example, the support element is selected from the group consisting of cellulose acetate, cardboard, crimped paper (such as crimped heat-resistant paper or crimped parchment paper), and polymeric materials (such as low density polyethylene (LDPE)). may be formed from one or more materials. In a preferred embodiment, the support element is provided as a hollow cellulose acetate tube.

Preferably, the support element has an outer diameter approximately equal to the outer diameter of the aerosol generating article. The support element may have an outer diameter of about 5 mm to about 12 mm, such as about 5 mm to about 10 mm, or about 6 mm to about 8 mm. In a preferred embodiment, the support element has an outer diameter of about 7.2 millimeters.

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

The support element can have a length of about 5 millimeters to about 15 millimeters. In one preferred embodiment, the support element has a length of about 8 millimeters.

During insertion of the heating element of the aerosol-generating device into the aerosol-forming matrix of the aerosol-generating article, the user must: It may be necessary to apply some force. This can damage one or both of the aerosol generating article and the heating element of the aerosol generating device. Additionally, the application of 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 can result in the heating elements of the aerosol generator not being fully inserted into the aerosol-forming substrate, which results in uneven and inefficient heating of the aerosol-forming substrate of the aerosol-generating article. can be caused. Advantageously, the support element is 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 millimeters. More preferably, the distance between the ventilation zone and the upstream end of the aerosol generating article is less than about 45 millimeters. Even more preferably, the distance between the ventilation zone and the upstream end of the aerosol generating article is less than about 40 millimeters.

Additionally or alternatively, it is preferred that the distance between the ventilation zone and the upstream end of the aerosol generating article be at least about 12 millimeters. More preferably, the distance between the ventilation zone and the upstream end of the aerosol generating article is preferably at least about 15 millimeters. Even more preferably, the distance between the ventilation zone and the upstream end of the aerosol generating article is preferably at least about 20 millimeters. In particularly preferred embodiments, the distance between the ventilation zone and the upstream end of the aerosol generating article is preferably at least about 25 millimeters.

Preferably, the distance between the ventilation zone and the downstream end of the rod of the aerosol generating substrate is at least about 2 millimeters. 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 millimeters. 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 millimeters. In some particularly preferred embodiments, the distance between the ventilation zone and the downstream end of the rod of the aerosol-generating substrate can be at least about 15 millimeters.

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 millimeters. 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 millimeters. 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 millimeters.

In practice, the venting zone comprises a recess internally defined by the hollow tubular segment, an upstream sub-recess extending longitudinally from the upstream end of the hollow tubular segment to the location of the venting zone, and an upstream sub-recess extending longitudinally from the upstream end of the hollow tubular segment to the location of the venting zone. and a downstream sub-recess extending longitudinally to the downstream end of the hollow tubular segment. Without being bound by theory, it is believed that in the upstream sub-cavity, the volatilized species of the aerosol stream traveling along the hollow tubular segment are slowly It is understood that the aerosol particles begin to nucleate as the air cools down. Meanwhile, in the downstream sub-concavity, the aerosol stream and flowing air are rapidly mixed, which quickly cools the volatilized species in the aerosol stream, and as the aerosol advances towards the mouthpiece, new aerosol particles are nucleated and existing This favors the growth of aerosol particles.

Preferably, the ratio between the length of the upstream depression and the length of the downstream depression is less than 1.5. More preferably, the ratio between the length of the upstream depression and the length of the downstream depression is less than 1. Even more preferably, the ratio between the length of the upstream depression and the length of the downstream depression is less than 0.67.

Additionally or alternatively, it is preferred that the ratio between the length of the upstream recess and the length of the downstream recess is at least about 0.15. More preferably, the ratio of the length of the upstream depression to the length of the downstream depression is preferably at least about 0.2. Even more preferably, the ratio of the length of the upstream depression to the length of the downstream depression is preferably at least about 0.35.

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

Preferably, the ratio of the length of the upstream section of the aerosol-generating article to the length of the downstream section of the aerosol-generating article is less than 2.5. More preferably, the ratio of the length of the upstream section of the aerosol-generating article to the length of the downstream section of the aerosol-generating article is less than two. Even more preferably, the ratio of the length of the upstream section of the aerosol-generating article to the length of the downstream section of the aerosol-generating article is less than 1.5. In particularly preferred embodiments, the ratio of the length of the upstream section of the aerosol-generating article to the length of the downstream section of the aerosol-generating article is less than 1.

Additionally or alternatively, it is preferred that the ratio of the length of the upstream section of the aerosol generating article to the length of the downstream section of the aerosol generating article be at least about 0.25. More preferably, the ratio of the length of the upstream section of the aerosol-generating article to the length of the downstream section of the aerosol-generating article is at least about 0.33. Even more preferably, the ratio of the length of the upstream section of the aerosol-generating article to the length of the downstream section of the aerosol-generating article is at least about 0.5.

Aerosol-generating articles according to the present invention advantageously facilitate adjustment and control of the overall RTD of the article. This is because the overall RTD of the article depends on the RTD of a finite, small number of components, and the provision of a ventilation zone contributes to lowering the overall RTD of the article. Therefore, RTD variations between aerosol generating articles can be advantageously reduced.

Accordingly, the invention may also provide a pack comprising 10 or more 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; The RTD of the aerosol-generating article having the lowest RTD among the aerosol-generating articles differs by less than 10 mm H ₂ O (about 100 Pascals). In such a pack, between the RTD of the aerosol-generating article having the highest RTD among the at least 10 aerosol-generating articles and the RTD of the aerosol-generating article having the lowest RTD among the at least 10 aerosol-generating articles. Preferably, the difference is less than 9 mm H ₂ O (about 90 Pascals), more preferably less than 8 mm H ₂ O (about 80 Pascals), and even more preferably less than 7 mm H ₂ O (about 70 Pascals). .
The present invention will be further described below with reference to the accompanying drawings.

FIG. 1 shows a schematic side cross-sectional view of an aerosol-generating article according to the invention. FIG. 2 shows a schematic side cross-sectional view of another embodiment of an aerosol-generating article according to the present invention. FIG. 3 shows a schematic side cross-sectional view of a further embodiment of an aerosol-generating article according to the invention.

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

The rods of aerosol generating substrate 12 have a length of about 12 millimeters and a diameter of about 7 millimeters. Rod 12 is cylindrical in shape and has a substantially circular cross section. Rod 12 includes a collection of sheets of homogenized tobacco material. The sheet of homogenized tobacco material contains 10 weight percent glycerin on a dry basis. Hollow cellulose acetate tube 14 has a length of approximately 8 millimeters and a thickness of 1 millimeter.

Mouthpiece segment 18 includes a plug of cellulose acetate tow that is 8 denier per filament and has a length of approximately 7 millimeters.

The hollow tubular segment 16 is provided as a cylindrical tube having a length of about 18 millimeters and a tube wall thickness of about 100 micrometers.

More specifically, the hollow tubular segment 16 may be formed from paper having a basis weight of 110 gsm, for example, and has a weight of 45 milligrams (ie, 2.5 milligrams/mm of length). The equivalent inner diameter of the hollow tubular segment 16 is approximately 7 millimeters. Accordingly, the volume of the cavity internally defined by hollow tubular segment 16 is approximately 693 cubic millimeters. As such, the ratio of the weight of the hollow tubular segment to the volume of the internal recess defined by the hollow tubular segment 16 is approximately 0.065. Aerosol generating article 10 includes a ventilation zone 26 provided approximately 5 millimeters from the upstream end of mouthpiece segment 18 . Accordingly, venting zone 26 is approximately 12 millimeters from the downstream end of the aerosol-generating article and approximately 13 millimeters from the upstream end of the hollow tubular segment.

Accordingly, vent zone 26 is approximately 21 millimeters from the downstream end of rod 12. FIG. 2 illustrates another embodiment 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. will be explained below to the extent that they differ. Hereinafter, the same reference numerals will be used wherever possible for corresponding components having the same structure or functional function.

In the aerosol-generating article 30 of FIG. 2, the rod 12 and hollow cellulose acetate tube 14 have the same length as the aerosol-generating article 10 of FIG. However, the mouthpiece segments include plugs of cellulose acetate tow that are 11 denier per filament and have a length of about 12 millimeters, and the hollow tubular segment 14 has a length of about 13 millimeters. A vent zone 26 is provided approximately 6 mm from the upstream end of the mouthpiece segment 18 and approximately 7 mm from the upstream end of the hollow tubular segment. Venting zone 26 is therefore approximately 15 millimeters from the downstream end of rod 12.

In the embodiment of FIG. 2, the hollow tubular segment 16 may be provided, for example, as a cylindrical tube of cellulose acetate having a length of about 18 millimeters and a peripheral wall thickness of about 1 millimeter, and weighing 171 millimeters. milligrams (i.e., 9.5 milligrams/mm of length).

The equivalent inner diameter of hollow tubular segment 16 may be approximately 5.3 millimeters. Accordingly, the volume of the cavity internally defined by hollow tubular segment 16 is approximately 397 cubic millimeters. Therefore, the ratio of the weight of the hollow tubular segment to the volume of the internal recess defined by the hollow tubular segment 16 is approximately 0.43. FIG. 3 illustrates yet another embodiment of an aerosol-generating article according to the present invention. Aerosol-generating article 40 of FIG. 3 differs structurally from aerosol-generating article 10 of FIG. 1 and aerosol-generating article 30 of FIG. 2 in that it does not include a hollow cellulose acetate tube as a support element. Therefore, the lengths of the three main components are also different. Hereinafter, the same reference numerals will be used wherever possible for corresponding components having the same structure or functional function.

In the aerosol generating article 40 of FIG. 3, the rod 12 has a length of about 12 millimeters, the hollow tubular segment 14 has a length of about 26 millimeters, the mouthpiece segment 18 has a length of about 12 millimeters, and a plug of cellulose acetate tow having 11 denier per filament. A ventilation zone 26 is provided approximately 5 millimeters from the upstream end of mouthpiece segment 18 and approximately 21 millimeters from the upstream end of the hollow tubular segment, coinciding with the downstream end of rod 12 in this embodiment.

Claims (10)

An aerosol-generating article for generating an inhalable aerosol when heated, the aerosol-generating article comprising:
an aerosol-generating base rod;
a mouthpiece segment including a plug of filtration material disposed downstream of and longitudinally aligned with the rod;
a hollow tubular segment located between the rod and the mouthpiece segment, longitudinally aligned with the rod and the mouthpiece segment, the hollow tubular segment at an upstream end of the mouthpiece segment; a hollow tubular segment defining a recess extending entirely up to;
a venting zone located along the hollow tubular segment;
the venting zone includes one or more rows of perforations formed through a peripheral wall of the hollow tubular segment less than 18 millimeters from an upstream end of the hollow tubular segment;
The total length of the aerosol generating article is 40 mm to 70 mm,
the length of the rod of the aerosol generating substrate is less than 40 mm;
the hollow tubular segment has a length of 10 mm to 30 mm;
the equivalent internal diameter of the hollow tubular segment at the location of the ventilation zone is at least 5 millimeters;
An aerosol-generating article, wherein the rod of the aerosol-generating substrate includes at least an aerosol former and has an aerosol former content of at least 10 percent on a dry mass basis. The aerosol-generating article of claim 1, wherein the hollow tubular segment includes a wrapper, the wrapper surrounding the rod and the mouthpiece segment. 2. The method of claim 1, wherein the hollow tubular segment includes a tube formed from a polymeric or cellulosic material, and the heated aerosol generating article further includes a wrapper surrounding the rod, the tube, and the mouthpiece segment. Aerosol-generating articles as described. An aerosol-generating article according to any preceding claim, wherein the equivalent internal diameter of the hollow tubular segment is substantially constant along the length of the hollow tubular segment. An aerosol-generating article according to any preceding claim, wherein the ventilation zone is located along the hollow tubular segment at least 4 millimeters from the upstream end of the mouthpiece segment. 5. The aerosol-generating article of claim 4, wherein the ventilation zone is located less than 25 millimeters along the hollow tubular segment from a downstream end of the mouthpiece segment. 7. A volumetric ratio of the ventilation airflow into the aerosol-generating article through the ventilation zone and the sum of the aerosol airflow and the ventilation airflow is less than 60 percent. Aerosol-generating articles as described. An aerosol-generating article according to any preceding claim, wherein the rod has a length of less than 15 millimeters. 9. The peripheral wall thickness of the hollow tubular segment at the location of the ventilation zone is less than 1.5 millimeters and greater than or equal to 100 micrometers. Aerosol-generating articles. An aerosol-generating article according to any one of claims 1 to 9 , wherein the aerosol-generating article has an RTD of 30 mm H ₂ O to 90 mm H ₂ O.