RU2804719C2 - Aerosol generation product with light hollow segment - Google Patents

Abstract

FIELD: aerosol systems.

SUBSTANCE: product contains a substrate rod for generating an aerosol, a hollow tubular segment at a location downstream relative to the rod. The tubular segment is longitudinally aligned with the rod and forms a cavity extending along its entire length from the upstream end of the tubular segment to the downstream end of the tubular segment. The mouthpiece segment contains a filter material rod and a recess at the mouthpiece end downstream relative to the filter material rod, a ventilation zone at a location along the hollow tubular segment at a distance of less than 20 millimeters from the downstream end of the product for generating aerosol. The ventilation zone contains one or more rows of perforations formed through the peripheral wall of a tubular segment having a length of 25 millimeters. The ratio between the weight of the tubular segment and the volume of the internal cavity formed by it is preferably less than 1 milligram/cubic millimeter. The aerosol generating substrate rod contains an aerosol generating agent that is at least 12 percent dry weight.

EFFECT: providing a satisfactory delivery of the aerosol with low variability of resistance to puff, high speed of manufacture of the product.

53 cl, 3 dwg, 2 tbl

Description

The present invention relates to an aerosol-generating article containing an aerosol-generating substrate and adapted to produce a respirable aerosol when heated.

Aerosol-generating products in which an aerosol-generating substrate (aerosol-generating substrate), such as a tobacco-containing substrate, is heated rather than burned are known in the art. Typically, in such heated smoking articles, an aerosol is generated by transferring heat from a heat source to a physically separate aerosol-generating substrate or material that may be located in contact with, within, around, or downstream of the heat source. During use of the aerosol generating article, volatile compounds are released from the aerosol generating substrate by heat transfer from the heat source and are entrained in air drawn through the aerosol generating article (aerosol generating article). As the released compounds cool, they condense 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 the aerosol is generated by transferring heat from one or more electrical heating elements of the aerosol generating device to an aerosol generating substrate of the aerosol generating article being heated.

In the past, substrates for heated aerosol generating products were typically prepared using randomly oriented cut pieces, strands, or strips of tobacco material. As an alternative, for example, international patent application WO-A-2012/164009 proposed rods for heated aerosol generating articles formed from collected sheets of tobacco material. The rods disclosed in WO-A-2012/164009 have a longitudinal porosity that allows air to be drawn through the rods. Essentially, folds in the assembled 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, which can be formed by casting, rolling, calendering or extruding a mixture containing bulk tobacco and at least one aerosol forming agent to form a sheet of homogenized tobacco material. In alternative embodiments, the rods of WO-A-2011/101164 may also be formed from strands of homogenized tobacco material obtained by extruding a mixture containing bulk tobacco and at least one aerosol forming agent to form homogenized tobacco material of continuous lengths.

Substrates for heated aerosol generating articles typically further contain an aerosol generating agent, ie, a compound or mixture of compounds that, when used, facilitate aerosol generation and which is preferably substantially resistant to thermal degradation at the operating temperature of the aerosol generating article. Examples of suitable aerosol-forming substances include: polyhydric alcohols such as propylene glycol, triethylene glycol, 1,3-butanediol and glycerin; polyhydric alcohol esters 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 for the production of a respirable aerosol by heating to include in the aerosol generating article one or more additional elements that are assembled in one wrapper with the substrate. Examples of such additional elements include a mouthpiece filter segment, a support element adapted to impart structural strength to the aerosol generating article, a cooling element adapted to cool the aerosol before reaching the mouthpiece, etc. However, although the inclusion of such additional elements has been proposed due to their advantageous effects, they typically complicate the overall design of the aerosol generating article and make its manufacture more complex and expensive. In fact, the manufacture of such multi-element aerosol generating products typically requires fairly complex manufacturing and assembly equipment.

In view of this, aerosol generating products have also been proposed which have a simpler design. However, in the absence of certain additional components, such as, for example, an aerosol cooling element, it may become more difficult to manufacture aerosol generating products that consistently provide the consumer with satisfactory aerosol delivery and RTD.

Thus, it would be desirable to provide an aerosol generating product that provides consistent, satisfactory delivery of aerosol to the consumer during use. Moreover, it would be desirable to provide an improved aerosol generating product that has a satisfactory RTD value. It would be equally desirable to provide an aerosol generating product that can be manufactured efficiently, at high speed, and preferably with low RTD variability from one product to another. The present invention is directed to providing a technical solution adapted to achieve at least one of the desired results described above.

According to an aspect of the present invention, there is provided an aerosol generating article for producing a respirable aerosol when heated, the aerosol generating article comprising:

an aerosol-generating substrate rod; and a hollow tubular segment at a location downstream of the rod. The hollow tubular segment is longitudinally aligned with the shaft and defines a cavity extending the entire length from the upstream end of the hollow tubular segment to the downstream end of the hollow tubular segment. In addition, the hollow tubular segment has a length of less than about 25 millimeters. The aerosol generating article further comprises a ventilation zone at a location along the hollow tubular segment. The ratio between the weight of the hollow tubular segment and the volume of the internal cavity formed by the hollow tubular segment is less than 1 milligram/cubic millimeter. The aerosol generating substrate rod contains at least an aerosol generating agent, wherein the aerosol generating agent content of the aerosol generating substrate rod is at least about 10 percent on a dry weight basis.

The term "aerosol generating product" is used herein to refer to a product in which an aerosol generating substrate is heated to produce and deliver a respirable aerosol to a consumer. As used herein, the term "aerosol generating substrate" means a substrate capable of releasing volatile compounds when heated to generate an aerosol.

A regular cigarette is lit when the user brings a flame to one end of the cigarette and draws air through the other end. The localized heat provided by the flame and oxygen in the air drawn through the cigarette causes the end of the cigarette to ignite, and the resulting combustion generates inhaled smoke. By comparison, in heated aerosol generating products, 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 the aerosol is generated by transferring heat from a combustible fuel element or heat source to a physically separate aerosol generating material. For example, the aerosol generating articles of the present invention find particular application in aerosol generating systems comprising an electrically heated aerosol generating device having an internal heating plate that is adapted to be inserted into a rod of an aerosol generating substrate (aerosol generating substrate). Aerosol generating products (aerosol generating products) of this type are described in the prior art, for example in document EP 0822670.

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

As used herein, the term “tubular segment” is used to refer to an elongated member defining a lumen, or channel for air flow, 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 air flow path establishing continuous fluid communication between the upstream end of the tubular element and the located further along the flow with the end of the tubular element. However, it should be understood that alternative cross-sectional geometries of the tubular element are possible.

As used herein, the term “longitudinal” refers to the direction corresponding to the major longitudinal axis of the aerosol generating article that extends between the upstream and downstream ends of the aerosol generating article. As used herein, the terms “upstream” and “downstream” describe the relative positions of elements or portions of elements of an aerosol generating article with respect to the direction in which the aerosol is transported during use through the aerosol generating article.

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

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

The term “tubular member peripheral wall thickness” is used herein to mean the minimum distance measured between the outer surface and the inner surface of the wall circumferentially delimiting the tubular member. In practice, the distance at a given location is measured along a direction substantially locally perpendicular to the outer surface and the inner surface of the tubular element. For a tubular element having a substantially circular cross-section, the distance is measured in the substantially radial direction of the tubular element.

In some embodiments, the peripheral wall thickness of the tubular element is constant. In alternative embodiments, the peripheral wall thickness of the tubular element varies along the length of the tubular element. The reason for this may be that the tubular member is formed from a material having an uneven surface finish (for example, the tubular member is provided in the shape of a cellulose acetate tube). Alternatively, the reason for this may be that the tubular member is designed to include a tapered section or the like. In those embodiments where the peripheral wall thickness of a tubular member varies along the length of the tubular member, the "tubular member peripheral wall thickness" is taken to be the average value calculated from multiple values measured as the minimum distance between the outer surface and the inner surface of the wall at different locations along length of the tubular element.

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 "airtight material" is used throughout this description to mean a material that does not allow fluids, particularly air and smoke, to pass through gaps or pores in the material. If 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 the air flow path formed by the tubular hollow segment inside it, and cannot flow through the peripheral wall of the hollow tubular segment. segment.

As used herein, the term “homogenized tobacco material” includes any tobacco material formed by agglomeration of particles of tobacco material. Sheets or webs of homogenized tobacco material are formed by agglomeration of bulk tobacco obtained by grinding or otherwise pulverizing one or both of tobacco leaf blades and tobacco leaf stems. Additionally, the homogenized tobacco material may contain trace amounts of one or more of tobacco dust, tobacco fines, and other bulk tobacco by-products generated during tobacco processing, handling, and shipping. Sheets of homogenized tobacco material can be produced by casting, extrusion, papermaking processes, or any other suitable methods known in the art.

The term "porous" is used herein to mean a material that has multiple pores or openings that allow air to pass through the material.

The term "ventilation rate" is used throughout this specification to refer to the volumetric ratio between the air flow admitted into the aerosol generating article through the ventilation zone (vent air flow) and the sum of the aerosol containing air flow and the ventilation air flow. The higher the degree of ventilation, the greater the dilution of the aerosol flow delivered to the consumer.

As briefly described above, the aerosol generating article of the present invention includes an aerosol generating substrate rod and a hollow tubular segment at a location downstream of the rod. These two elements are aligned longitudinally. The aerosol-generating substrate rod contains at least an aerosol-generating substance.

Unlike known aerosol generating articles, the aerosol generating agent content of the aerosol generating substrate rod (aerosol generating substrate) is at least about 10 percent on a dry weight basis. In addition, the hollow tubular segment defines a cavity extending the entire length from the upstream end of the hollow tubular segment to the downstream end of the hollow tubular segment and having a length of less than about 25 millimeters. A ventilation zone is provided at a location along the hollow tubular segment. Additionally, the ratio between the weight of the hollow tubular segment and the volume of the internal cavity formed by the hollow tubular segment is less than 1 milligram/cubic millimeter.

By providing an aerosol generating article, in which a hollow tubular element is disposed between the rod of the aerosol generating substrate and the mouth end of the aerosol generating article, and in which the hollow tubular element defines a cavity extending the entire length of an upstream end of the hollow tubular segment to the downstream end of the hollow tubular segment, the overall structural complexity of the product can be significantly reduced compared to existing aerosol generating products. This advantageously simplifies the manufacturing method and reduces the complexity of the manufacturing and assembly equipment required to implement the manufacturing method.

One such aerosol generating article does not contain an aerosol cooling element adapted to reduce the temperature of the aerosol stream drawn through the aerosol generating article, as is the case, for example, in the case of aerosol generating articles that are described in international patent application WO 2013/ 120565.

The inventors have discovered that satisfactory cooling of the aerosol stream generated by 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 have unexpectedly discovered that by using a hollow tubular segment having a length of less than about 25 millimeters, in which the ratio between the weight of the hollow tubular segment and the volume of the internal cavity formed by the hollow tubular segment is less than 1 milligram/cubic millimeter, it is possible to counteract the effects of increased aerosol dilution caused by the intake of ventilation air into the product.

Without being limited by theory, it is believed that since the temperature of the aerosol stream is rapidly reduced by the introduction of ventilation air as the aerosol moves towards the mouthpiece end, the ventilation air being introduced into the aerosol stream at a location relatively close to the upstream end of the hollow tubular segment (t i.e. sufficiently close to the heat source and the substrate rod generating the aerosol), a sharp cooling of the aerosol flow is achieved, which has a beneficial effect on the condensation and nucleation of aerosol particles. Accordingly, the overall ratio of the particulate aerosol phase to the gaseous phase of the aerosol can be improved compared to existing non-ventilated aerosol generating products.

By providing a cavity as large a volume as in the case of the articles of the present invention, a cooling chamber is effectively provided which can promote condensation of the aerosol particles earlier in the flow relative to the mouth end of the article, since nucleation phenomena are enhanced as the flow of the aerosol slows down. Without being limited by theory, it is understood that providing a sufficiently wide tubular cavity downstream of the aerosol generating substrate rod will facilitate the generation of a satisfactory amount of aerosol during use. In turn, a large proportion of the generated aerosol particles begin to condense before reaching the mouthpiece end of the product.

At the same time, the hollow tubular segments within the above-described ranges provide sufficient structural strength of the article and hold the shaft of the aerosol generating article (aerosol generating article) at a predetermined distance from the mouthpiece end of the article. Accordingly, such hollow tubular segments provide a chamber long enough for the aerosol stream to flow in such that sufficient time is available during use for the temperature of the vaporized compounds to decrease and for nucleation of the aerosol particles to occur. In addition, a relatively short hollow tubular segment, as in the aerosol generating articles of the present invention, has been found to provide satisfactory aerosol nucleation while not providing the aerosol particles with a sufficiently large surface area on which to condense.

In practice, in the aerosol generating articles of the present invention, the cross-sectional surface area of the cavity of the hollow tubular segment can be maximized, and at the same time, the hollow tubular segment can be ensured to have sufficient structural strength to prevent the aerosol generating article from shrinking, as well as to provide some support for the aerosol generating substrate rod and to minimize the RTD of the hollow tubular segment. It is understood that large values of the cross-sectional surface area of the cavity of a hollow tubular segment are associated with a decrease in the flow velocity of the aerosol moving along the aerosol-generating article, which is also expected to favor aerosol nucleation.

In addition, by using a hollow tubular segment having a smaller thickness, such as less than 1.5 millimeters in thickness, it has been found that the ventilation air can be substantially prevented from diffusion before it contacts and mixes with the aerosol flow, which is understood to be additionally contributes to nucleation phenomena. In practice, by providing more controlled, localized cooling of the vaporized compound stream, the effect of cooling on the formation of new aerosol particles can be enhanced.

In fact, the inventors have unexpectedly discovered how the beneficial effect of improved nucleation can significantly counteract the less desirable dilution effects such that the aerosol generating articles of the present invention consistently achieve satisfactory aerosol delivery values. This is particularly advantageous for “short” aerosol generating articles, such as articles in which the length of the aerosol generating substrate rod is less than about 40 millimeters, preferably less than 25 millimeters, even more preferably less than 20 millimeters, or in which the overall length of the article aerosol generating is less than about 70 millimeters, preferably less than about 60 millimeters, even more preferably less than 50 millimeters. It should be understood that in such aerosol generating products there is little time and space for aerosol generation and for making the particulate phase of the aerosol available for delivery to the consumer.

In addition, since the hollow tubular member does not substantially affect the RTD of the aerosol generating article in aerosol generating articles, according to the present invention, the overall RTD of the article can be advantageously finely adjusted by adjusting the length and density of the aerosol generating substrate rod or the length and density of the segment of the filter material in the mouthpiece segment in those embodiments where a mouthpiece segment is present. This allows aerosol generating substrates that have a specified RTD to be manufactured efficiently and with greater precision, and thus satisfactory RTD levels can be provided to the consumer even in the presence of ventilation.

The aerosol generating articles of the present invention can be manufactured in a continuous process that can be efficiently carried out at high speed, and can be conveniently manufactured on existing production lines for making heated aerosol generating articles, without the need for extensive modifications to the production equipment.

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

Preferably, the aerosol generating substrate rod has an outer diameter of at least 5 millimeters. The aerosol generating substrate rod may have an outer diameter of from about 5 millimeters to about 12 millimeters, such as from about 5 millimeters to about 10 millimeters, or from about 6 millimeters to about 8 millimeters. In a preferred embodiment, the aerosol generating substrate rod has an outer diameter of 7.2 millimeters within 10 percent accuracy.

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

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 preferred embodiments, the aerosol generating substrate comprises one or more assembled sheets of homogenized tobacco material. Preferably, one or more sheets of homogenized tobacco material are textured. As used herein, the term “textured sheet” means a sheet that has been corrugated, embossed, blind embossed, perforated, or otherwise deformed. Textured sheets of homogenized tobacco material for use in the present invention may contain a plurality of spaced apart indentations, projections, perforations, or a combination thereof. According to a particularly preferred embodiment of the present invention, the aerosol generating substrate rod comprises an assembled corrugated sheet of homogenized tobacco material surrounded by a wrapper.

As used herein, the term "corrugated sheet" is intended to be used synonymously with the term "creped sheet" and means a sheet having a plurality of substantially parallel folds or corrugations. Preferably, the corrugated sheet of homogenized tobacco material contains a plurality of folds or corrugations substantially parallel to the cylindrical axis of the rod according to the present invention. This advantageously facilitates the assembly of the corrugated sheet of homogenized tobacco material to form a rod. However, it should be understood that the corrugated sheets of homogenized tobacco material for use in the present invention may alternatively or additionally comprise a plurality of substantially parallel folds or corrugations located at an acute or obtuse angle to the cylindrical axis of the rod. In some embodiments, sheets of homogenized tobacco material for use in the core of an article according to the present invention may be substantially uniformly textured over substantially their entire surface. For example, corrugated sheets of homogenized tobacco material for use in making a rod used in an aerosol generating article of the present invention may comprise a plurality of substantially parallel folds or corrugations that are substantially evenly spaced across the width of the sheet.

Sheets or webs of homogenized tobacco material for use in the invention may have a tobacco content of at least about 40 percent by weight on a dry weight basis, more preferably at least about 60 percent by weight on a dry weight basis, more preferably or at least about 70 percent by weight on a dry weight basis, and most preferably at least about 90 percent by weight on a dry weight basis.

Sheets or webs of homogenized tobacco material for use in an aerosol generating substrate may contain one or more internal binders, i.e., endogenous tobacco binders, one or more external binders, i.e., exogenous tobacco binders, or a combination thereof to help agglomerate the bulk tobacco. Alternatively or additionally, sheets of homogenized tobacco material for use in the aerosol generating substrate may contain other additives, including, but not limited to, tobacco and non-tobacco fibers, aerosol formers, humectants, plasticizers, flavoring agents, fillers, aqueous and non-aqueous solvents and the same. combinations.

Suitable external binders for inclusion in sheets or webs of homogenized tobacco material for use in an aerosol generating substrate are known in the art and include, but are not limited to: gums such as, for example, guar gum, xanthan gum, gum arabic and locust bean gum wood; cellulosic binders such as, for example, hydroxypropylcellulose, carboxymethylcellulose, hydroxyethylcellulose, methylcellulose and ethylcellulose; polysaccharides, such as, for example, starches, organic acids, such as alginic acid, salts of bases conjugate with organic acids, such as sodium alginate, agar and pectins; and their combinations.

Suitable non-tobacco fibers for inclusion in sheets or webs of homogenized tobacco material for use in an aerosol generating substrate are known in the art and include, but are not limited to: cellulose fibers; softwood fibers; hardwood fibers; jute fibers and their combinations. Prior to inclusion in sheets of homogenized tobacco material for use in an aerosol generating substrate, non-tobacco fibers may be subjected to suitable methods known in the art, including, but not limited to: mechanical pulping; cleaning; chemical pulp production; bleaching; sulfate pulp production; and their combinations.

Preferably, the sheets or webs of homogenized tobacco material contain an aerosol-forming agent. As used herein, the term "aerosol generating agent" describes any suitable known compound or mixture of compounds that, when used, facilitates the formation of an aerosol and that is substantially resistant to thermal degradation at the operating temperature of the aerosol generating article.

Suitable aerosol-forming agents are known in the art and include, but are not limited to: polyhydric alcohols such as propylene glycol, triethylene glycol, 1,3-butanediol and glycerol; polyhydric alcohol esters 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 or mixtures thereof, such as propylene glycol, triethylene glycol, 1,3-butanediol, and most preferably glycerol.

Sheets or webs of homogenized tobacco material may contain a single aerosol-forming agent. Alternatively, sheets or webs of homogenized tobacco material may contain a combination of two or more substances to form an aerosol.

Sheets or webs of homogenized tobacco material have an aerosol forming agent content of more than 10 percent on a dry weight basis. Preferably, the sheets or webs of homogenized tobacco material have an aerosol forming agent content of greater than 12 percent on a dry weight basis. More preferably, the sheets or webs of homogenized tobacco material have an aerosol forming agent content of greater than 14 percent on a dry weight basis. Even more preferably, the sheets or webs of homogenized tobacco material have an aerosol forming agent content of greater than 16 percent on a dry weight basis.

The aerosol-forming agent content of the sheets of homogenized tobacco material may range from about 10 percent to about 30 percent on a dry weight basis. Preferably, the sheets or webs of homogenized tobacco material have an aerosol forming agent content of less than 25 percent on a dry weight basis.

In a preferred embodiment, the aerosol forming agent content of the sheets of homogenized tobacco material is approximately 20 percent on a dry weight basis.

Sheets or webs of homogenized tobacco for use in the aerosol generating product of the present invention can be manufactured by methods known in the art, for example by methods disclosed in international patent application WO-A-2012/164009 A2. In a preferred embodiment, sheets of homogenized tobacco material for use in an aerosol generating product are formed from a slurry containing bulk tobacco, guar gum, cellulose fibers and glycerin by an injection molding process.

Alternative arrangements of homogenized tobacco material in a rod for use in an aerosol generating article are known to those skilled in the art and may include a plurality of stacked sheets of homogenized tobacco material, a plurality of elongated tubular members formed by twisting strips of homogenized tobacco material about their longitudinal axes, etc.

As a further alternative, the aerosol generating substrate rod may comprise a non-tobacco based nicotine-containing material, such as a sheet of non-tobacco sorbent material incorporated with nicotine (eg, in the form of a nicotine salt) and an aerosol generating agent. Examples of such rods are described in international application WO-A-2015/052652. In addition 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 rod of the articles of the present invention, the aerosol generating substrate is preferably surrounded by a wrapper. The wrapper may be formed from 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 aerosol generating articles of the present invention may optionally comprise a mouthpiece segment at a location downstream of the hollow tubular segment, preferably in end-to-end contact with the hollow tubular segment. In such products, the cavity of the hollow tubular segment extends along the entire length to the upstream end of the mouthpiece segment.

The mouthpiece typically includes a filter material rod configured to remove particulate components, gaseous components, or a combination thereof. Suitable filter materials are known in the art and include, but are not limited to: fibrous filter materials, such as, for example, cellulose acetate tow; viscose fibers, polyhydroxyalkanoate (PHA) fibers, polylactic acid (PLA) fibers and paper; adsorbents such as, for example, activated alumina, zeolites, molecular sieves and silica gel; and their combinations. Additionally, the filter material rod may further contain one or more aerosol modifying agents. Suitable aerosol modifying agents 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 recess at the mouthpiece end downstream of the filter material rod. For example, the mouthpiece may comprise a hollow tube longitudinally aligned with a plug of filter material and immediately downstream of a plug of filter material, the hollow tube defining a cavity at the mouthpiece end that is open to the external environment at the downstream end. mouthpiece and aerosol-generating product.

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

In other embodiments, a similar segment of filter material may alternatively or additionally be provided at a location between the aerosol generating substrate rod and the hollow tubular segment.

The hollow tubular segment is preferably an annular tube defining and defining an air gap within the aerosol generating article. In practice, the hollow tubular segment provides a chamber for vaporized aerosol components released when the aerosol-generating substrate is heated for accumulation and inflow. As briefly described above, this chamber extends longitudinally along the entire length from the upstream end of the hollow tubular segment to the downstream end of the hollow tubular segment.

Thus, in the aerosol generating articles of the present invention, the hollow tubular segment holds the rod of the aerosol generating substrate at a predetermined distance from the mouthpiece end of the article and provides an elongated air flow path for generating an aerosol and flowing to the mouthpiece end of the article. During use, a temperature difference occurs along this air flow channel. In practice, the temperature difference is provided such that the temperature of the evaporated aerosol components entering the hollow tubular segment at the upstream end is greater than the temperature of the evaporated aerosol components leaving the hollow tubular segment at the downstream end (i.e. the upstream end of the mouthpiece, if a mouthpiece is present).

On the other hand, the hollow tubular segment is required to withstand any axial compressive load or bending moment that may be applied to the hollow tubular segment during manufacture of the aerosol generating article. In addition, the hollow tubular segment is required to provide structural strength to the aerosol generating article so that it can be easily handled and inserted into the aerosol generating device by the user for use. On the other hand, it is desirable that the total volume of the chamber formed by the hollow tubular segment within it be as large as possible to promote aerosol formation and facilitate delivery of the aerosol to the consumer.

To meet these requirements, as briefly described above, the ratio between the weight of the hollow tubular segment and the volume of the internal cavity formed by the hollow tubular segment is less than 1 milligram/cubic millimeter. More preferably, the ratio between the weight of the hollow tubular segment and the volume of the internal cavity formed by the hollow tubular segment is less than 0.5 milligrams/cubic millimeter. Even more preferably, the ratio between the weight of the hollow tubular segment and the volume of the internal cavity formed by the hollow tubular segment is less than 0.2 milligrams/cubic millimeter. In particularly preferred embodiments, the ratio between the weight of the hollow tubular segment and the volume of the internal cavity formed by the hollow tubular segment is less than 0.1 milligrams/cubic millimeter.

In the hollow tubular segments, having a relationship between the weight of the hollow tubular segment and the volume of the internal cavity formed by the hollow tubular segment, which is within the above-described ranges, the volume of the cavity is advantageously maximized, and at the same time it is ensured that the hollow tubular segment contributes to the overall structural strength of the aerosol generating article and effectively holds the rod of the aerosol generating substrate away from the mouthpiece end of the article.

In an exemplary embodiment, the hollow tubular segment has an internal equivalent diameter of 7 millimeters and is formed from a wrapper having a basis weight of 110 g/m ² wherein it has a weight of 2.5 milligrams/mm. For one such hollow tubular segment, the ratio between the weight of the hollow tubular segment and the volume of the internal cavity formed by the hollow tubular segment is approximately 0.065 milligrams/cubic millimeter.

In another exemplary embodiment, the hollow tubular segment has an internal equivalent diameter of 5.3 millimeters and can be provided as a cellulose acetate tube with a weight of 9.5 milligrams/mm. For one such hollow tubular segment, the ratio between the weight of the hollow tubular segment and the volume of the internal cavity formed by the hollow tubular segment is approximately 0.43 milligrams/cubic millimeter.

Preferably, the thickness of the peripheral wall of the hollow tubular segment is less than 1.5 millimeters. Preferably, the thickness of the peripheral wall of the hollow tubular segment is less than 1250 micrometers, more preferably less than 1000 micrometers, even more 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 thickness of the hollow tubular segment is at least about 100 micrometers. Preferably, the thickness of the peripheral wall of the hollow tubular segment is at least about 200 micrometers.

Without being limited by theory, it has been found that by using a hollow tubular segment comprising a peripheral wall with a thickness within the ranges described above, it is advantageously possible to limit or even substantially prevent the diffusion of ventilation air before it contacts and mixes with the aerosol flow. This, as is clear, further promotes nucleation phenomena. In practice, by providing more controlled localized cooling to the stream of vaporized compounds drawn through the hollow tubular segment, the effect of cooling on the formation of new aerosol particles can be enhanced.

Preferably, the equivalent internal diameter of the hollow tubular segment is at least about 4 millimeters. The term "equivalent internal diameter" is used herein to refer to the diameter of a circle that has the same surface area as the cross-section of the air flow channel formed by the hollow tubular segment within it. The cross-section of the air flow channel may have any suitable shape. However, as briefly described above, a circular cross-section is preferred, i.e. the hollow tubular segment is actually a cylindrical tube. In this case, the equivalent inner diameter of the hollow tubular segment is essentially the same as the inner diameter of the cylindrical tube.

More preferably, the equivalent internal diameter of the hollow tubular segment is at least about 5 millimeters, even more preferably at least about 5.25 millimeters, most preferably at least about 5.5 millimeters. In some embodiments, the equivalent internal 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.

Additionally, the equivalent inner diameter of the hollow tubular segment is preferably less than about 10 millimeters. More preferably, the equivalent internal diameter of the hollow tubular segment is less than about 9.5 millimeters, 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 internal diameter of the hollow tubular segment is substantially constant along the length of the hollow tubular segment. In other embodiments, the equivalent internal diameter of the hollow tubular segment may vary along the length of the hollow tubular segment.

The inventors have surprisingly discovered that aerosol generating articles according to the present invention that include a hollow tubular segment having an equivalent internal diameter within the above-described ranges can provide particularly satisfactory aerosol delivery values. Without being limited by theory, it is believed that an aerosol stream flowing along a hollow tubular segment that has an equivalent internal diameter within the above-described ranges is forced to flow at a relatively low velocity when receiving the incoming cooling ventilation air stream into the aerosol stream and mixing with the aerosol stream. Because the aerosol flow moves relatively slowly along the hollow tubular segment, the beneficial effect of cooling on aerosol nucleation is expected to be maximized under these conditions.

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

As briefly described above, the aerosol generating articles of the present invention include a ventilation zone located at a location along the hollow tubular segment. Preferably, the ventilation zone is provided at a location 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.

In addition or alternatively, the distance between the ventilation zone and the upstream end of the hollow tubular segment is preferably 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.

In those embodiments of aerosol generating articles of the present invention that include a mouthpiece, the ventilation zone is preferably provided at a location along the hollow tubular segment at a distance of at least 2 millimeters from the upstream end of the mouthpiece. Preferably, the ventilation zone is provided at a location along the hollow tubular segment at a distance of at least 4 millimeters from the upstream end of the mouthpiece. Even more preferably, the ventilation zone is provided at a location along the hollow tubular segment at a distance of 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 into the hollow tubular segment through the venting zone is mixed with the aerosol. This quickly reduces the temperature of the aerosol mixture and at the same time partially dilutes the mixture of air and aerosol particles. However, by providing a ventilation zone relative to the upstream end of the mouthpiece segment at a distance within the above-described ranges, a cooling chamber is effectively provided immediately upstream of the mouthpiece, which advantageously promotes nucleation and growth of aerosol particles. Thus, the dilution effect of the ventilation air introduced into the hollow tubular segment is at least partially counteracted, which advantageously provides satisfactory levels of aerosol delivery to the consumer.

In some embodiments, the ratio between the distance from the vent zone to the upstream end of the hollow tubular segment and the equivalent internal diameter of the hollow tubular segment at the location of the vent zone is less than 4. Preferably, the ratio between the distance from the vent zone to the upstream end of the hollow tubular segment 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 from the ventilation zone to 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 between the distance from the ventilation zone to 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 particularly preferred embodiments, the ratio between the distance from the ventilation zone to 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 2, more preferably less than 1.5, even more preferably less than 1.2 .

Preferably, the ventilation zone is provided at a location along the hollow tubular segment at a distance of at least 10 millimeters from the downstream end of the aerosol generating article. More preferably, the ventilation zone is provided at a location along the hollow tubular segment at a distance of at least 12 millimeters from the downstream end of the aerosol generating article. Even more preferably, the ventilation zone is provided at a location along the hollow tubular segment at a distance of at least 15 millimeters from the downstream end of the aerosol generating article. This is advantageous in that it ensures that the ventilation zone is not blocked by the user's lips during use.

In addition or alternatively, the ventilation zone is preferably located at a location along the hollow tubular segment at a distance of less than 25 millimeters from the downstream end of the aerosol generating article. More preferably, the ventilation zone is at a location along the hollow tubular segment at a distance of less than 20 millimeters from the downstream end of the aerosol generating article. This advantageously ensures that during use, when the aerosol generating article is placed in the heating chamber of the electrically heated aerosol generating device, the ventilation zone is actually located at a location along the hollow tubular segment protruding outward from the heating chamber so that external cooling air can easily retracted into the hollow tubular segment.

In some preferred embodiments, the venting zone is provided at a location along the hollow tubular segment at a distance of about 10 millimeters to about 25 millimeters from the downstream end of the aerosol generating device, more preferably from about 12 millimeters to about 20 millimeters from the downstream end of the aerosol generating device. the flow path of the end of the aerosol generating device. In an exemplary embodiment, a ventilation zone is provided at a location along the hollow tubular segment at a distance of 18 millimeters from the downstream end of the aerosol generating article. In another exemplary embodiment, a ventilation zone is provided at a location along the hollow tubular segment at a distance of 13 millimeters from the downstream end of the aerosol generating article.

The ventilation rate of the aerosol generating article may typically be at least about 10 percent, preferably at least about 20 percent.

In preferred embodiments, the ventilation rate of the aerosol generating article is at least about 30 percent. More preferably, the ventilation rate of the aerosol generating article is at least about 35 percent. In addition or alternatively, the ventilation rate of the aerosol generating article is less than about 60 percent. More preferably, the ventilation rate of the aerosol generating article is less than about 50 percent. In particularly preferred embodiments, the ventilation rate of the aerosol generating article is from about 30 percent to about 60 percent. More preferably, the ventilation rate of the aerosol generating article is from about 35 percent to about 50 percent. In some particularly preferred embodiments, the ventilation rate of the aerosol generating article is approximately 40 percent.

Without being limited by theory, the inventors have discovered that the temperature difference caused by the introduction of coolant, external 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 an aerosol from a gaseous mixture containing various chemical compounds depends on the subtle interaction of nucleation, evaporation and condensation, and droplet coalescence, while taking into account changes in vapor concentration, temperature and velocity fields. The so-called classical theory of nucleation is based on the assumption that the fraction of molecules in the gas phase is large enough for them to remain linked for a long time with a sufficient probability (for example, a fifty-fifty probability). These molecules represent some kind of critical threshold molecular clusters among short-lived molecular aggregates, and this means that, in general, smaller molecular clusters in the gas phase are more likely to decay quite quickly, while larger clusters are generally more likely to grow . Such a critical cluster is identified with the key nucleation nucleus, from which droplets are expected to grow due to the condensation of molecules from the vapor. It is assumed that the primary droplets that have just formed appear with a certain initial diameter and can then grow by several orders of magnitude. This is simplified and can be accelerated by rapid cooling of the surrounding steam, which causes condensation. Thus, this helps to take into account that evaporation and condensation are two sides of the same mechanism, namely mass transfer between gas and liquid. While evaporation refers to the net mass transfer from liquid droplets to the gas phase, condensation is the net mass transfer from the gas phase to the droplet phase. Evaporation (or condensation) will cause the volume of droplets to decrease (or grow) but will not change the number of droplets.

In this scenario, which can be further complicated by droplet coalescence phenomena, temperature and cooling rate can play an important role in determining the system response. In general, different cooling rates can lead to significantly different time behavior with regard to the formation of the liquid phase (droplets), since the nucleation process is usually non-linear. Without being limited by theory, it is assumed that cooling can cause a rapid decrease in the number concentration of droplets, followed by a strong short-term increase in their growth (nucleation burst). This burst of nucleation may be more significant at lower temperatures. In addition, it may be that higher cooling rates may promote earlier onset of nucleation. In comparison, decreasing the cooling rate may have a beneficial effect on the final size that aerosol droplets ultimately reach.

Thus, the rapid cooling caused by the introduction of external air into the hollow tubular segment through the ventilation zone can be advantageously used to promote nucleation and growth of aerosol droplets. However, at the same time, the immediate disadvantage of introducing external air into the hollow tubular segment is the dilution of the aerosol flow delivered to the consumer.

The inventors have surprisingly discovered that the effect of dilution on the aerosol, which can be assessed by measuring in particular the effect on the delivery of glycerol contained in the aerosol generating substrate as an aerosol generating agent, is advantageously minimized when the ventilation rate is between 30 percent to 50 percent. In particular, ventilation rates of 35 percent to 42 percent have been found to result in particularly satisfactory glycerol delivery values.

Additionally, the inventors have discovered that in the aerosol generating articles of the present invention, the cooling and dilution effects caused by the intake of ventilation air at a location along the channel formed by the above-described hollow tubular segment have an unexpected reducing effect on the generation and delivery of phenol-containing compounds.

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 contains only one row of perforations. It will be understood that this is advantageous in that by concentrating the cooling effect due to ventilation on a short portion of the cavity formed by the hollow tubular segment, aerosol nucleation can be further improved. The reason for this is that faster and sharper cooling of the vaporized compound stream is expected to be particularly conducive to the formation of new aerosol particle nuclei.

Preferably, one or more rows of perforations are located around the circumference of the wall of the hollow tube. If the ventilation zone contains two or more rows of perforations formed through the peripheral wall of the hollow tubular segment, these rows are spaced apart from each other in the longitudinal direction along the hollow tubular segment. For example, adjacent rows of perforations may be spaced apart from each other in the longitudinal direction by a distance of from approximately 0.25 millimeters to 0.75 millimeters.

The equivalent diameter of at least one of the ventilation perforations is preferably 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" is used herein to refer to the diameter of a circle having 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, round perforations are preferred.

The ventilation perforations may be of the same size. Alternatively, the ventilation perforations can be varied in size. By changing the number and size of the vent perforations, the amount of outside air admitted into the hollow tubular segment when the user takes a puff on the mouthpiece end of the aerosol generating article during use can be adjusted. In particular, the degree of ventilation of the aerosol generating article can be advantageously controlled.

The ventilation perforations may be formed using any suitable technique, such as laser technology, mechanical perforation of a hollow tubular segment as part of an aerosol generating article, or pre-perforation of a hollow tubular segment before combining it with other elements to form an aerosol generating article. Preferably, the ventilation perforations are formed using in-line laser perforation.

The length of the hollow tubular segment is preferably 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. 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 from about 10 millimeters to about 30 millimeters, more preferably from about 12 millimeters to about 25 millimeters, even more preferably from about 15 millimeters to about 20 millimeters. For example, in a particularly preferred embodiment, the length of the hollow tubular segment is approximately 18 millimeters. In another particularly preferred embodiment, the length of the hollow tubular segment is approximately 13 millimeters.

The overall length of the aerosol generating article of the present invention is preferably at least about 40 millimeters. In addition or alternatively, the overall length of the aerosol generating article of the present invention is preferably less than about 70 millimeters, more preferably less than 60 millimeters, even more preferably less than 50 millimeters. In preferred embodiments, the overall length of the aerosol generating article is from about 40 millimeters to about 70 millimeters. In an exemplary embodiment, the overall length of the aerosol generating article is approximately 45 millimeters.

The hollow tubular segment is preferably formed from a substantially airtight material. Accordingly, 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 through the peripheral wall of the hollow tubular element.

In some embodiments, the hollow tubular segment includes a wrapper, the wrapper also surrounding the rod. If a mouthpiece segment is present, the wrapper also surrounds the mouthpiece segment. In practice, a wrapper having a thickness within the ranges described above is used to surround and connect the aerosol generating substrate rod (and optionally the mouthpiece segment), with the wrapper effectively forming the peripheral wall of the hollow tubular element.

For example, one such unit wrap that connects the rod and the mouthpiece segment may have a basis weight of less than at least about 70 grams/square meter ( ^gsm ). Preferably, one such unit wrap that connects the shaft and the mouth end 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 union wrap connecting the shaft and the mouthpiece segment 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 material or cellulosic material, wherein the heated aerosol generating article further comprises a wrapper surrounding the rod, the tube, and an optional mouthpiece segment. For example, the cellulosic material may comprise paper or paperboard, or a mixture thereof.

For example, the hollow tubular segment may include a tube formed from an extruded plastic tube. Alternatively, the hollow tubular segment may comprise a tube formed from multiple overlapping paper layers, such as multiple parallel-twisted paper layers or multiple helically-twisted paper layers. Forming a tube of multiple overlapping paper layers can further improve resistance to compression or deformation. Preferably the tube contains two or more paper layers. Alternatively or additionally, the tube preferably contains less than eleven paper layers.

One such tube may be made airtight using substantially airtight paper. The term “substantially airtight paper” is used herein to mean paper having an air permeability of less than about 20 CORESTA units, more preferably less than about 10 CORESTA units, most preferably less than about 5 CORESTA units, measured according to ISO 2965:2009. Alternatively, adjacent paper layers in a tube may be held together by an adhesive, giving the tube sealing properties.

Suitable materials for forming the tube are known in the art and include, but are not limited to, cellulose acetate, stiff paper (ie paper having a basis weight of at least 90 grams/square meter), polymer films such as cellulose films, and paperboard.

In the aerosol generating article of the present invention, the overall RTD of the article depends substantially on the RTD of the rod and, if a mouthpiece is present, on the RTD of the mouthpiece, since the hollow tubular segment is substantially empty and, as such, has only a substantially minor effect on the overall RTD . In practice, the hollow tubular segment may be adapted to generate RTD in the range of approximately 1 millimeter of water. Art. (approximately 10 Pa) to approximately 20 millimeters of water. Art. (approximately 200 Pa). Preferably, the hollow tubular segment is adapted to generate RTD from approximately 2 millimeters of water. Art. (approximately 20 Pa) to approximately 10 millimeters of water. Art. (approximately 100 Pa).

The aerosol generating product preferably has a total RTD of less than about 90 millimeters of water. Art. (approximately 900 Pa). More preferably, the aerosol generating article has a total RTD of less than about 80 millimeters of water. Art. (approximately 800 Pa). Even more preferably, the aerosol generating article has a total RTD of less than about 70 millimeters of water. Art. (approximately 700 Pa).

In addition or alternatively, the aerosol generating article preferably has a total RTD of at least about 30 millimeters of water. Art. (approximately 300 Pa). More preferably, the aerosol generating article has a total RTD of at least about 40 millimeters of water. Art. (approximately 400 Pa). Even more preferably, the aerosol generating article has a total RTD of at least about 50 millimeters of water. Art. (approximately 500 Pa).

The RTD of an aerosol generating product can be defined as the negative pressure that must be applied, under the test conditions specified in ISO 3402, to the downstream end of the product (the mouthpiece segment, if a mouthpiece segment is present) to maintain uniform volumetric air flow 17. 5 ml/s through the mouthpiece segment. The RTD values listed above are intended to be measured against the aerosol generating device itself (i.e., prior to insertion of the product into the aerosol generating device) without blocking the ventilation zone perforations.

If desired or necessary, for example to achieve a sufficiently high RTD of the aerosol generating article, the length and density (in units of deniers per thread) of the filter material of the optional mouthpiece can be adjusted. In addition or alternatively, an additional filter section may be included in the aerosol generating article. For example, such an additional filter section may be included between the aerosol generating substrate rod and the hollow tubular segment. Preferably, such additional filter section contains a filter material such as, for example, cellulose acetate. Preferably, the length of the additional filter section is from about 4 millimeters to about 8 millimeters, preferably from about 5 millimeters to about 7 millimeters.

In some embodiments, the aerosol generating article of the present invention may comprise an additional support member positioned between and longitudinally aligned with the aerosol generating substrate rod and the hollow tubular segment. In detail, 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 made of any suitable material or combination of materials. For example, the support element may be made of one or more materials selected from the group consisting of: cellulose acetate; cardboard; corrugated paper such as corrugated heat-resistant paper or corrugated parchment paper; and polymeric materials such as low-density polyethylene (LDPE). In a preferred embodiment, the support element is provided in the form of a hollow cellulose acetate tube.

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

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

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

When inserting the heating element of the aerosol generating device into the aerosol generating substrate of the aerosol generating article, the user may be required to apply some force to overcome the resistance of the aerosol generating substrate of the aerosol generating article to insert the heating element of the aerosol generating device. This may damage the aerosol generating product and/or the heating element of the aerosol generating device. Additionally, applying force when inserting the heating element of the aerosol generating device into the aerosol-generating substrate of the aerosol-generating article may displace the aerosol-generating substrate within the aerosol-generating article. This may result in incomplete insertion of the aerosol generating device's heating element into the aerosol generating substrate, which may result in uneven and ineffective heating of the aerosol generating substrate or aerosol generating article. The support member is advantageously configured to resist movement of the aerosol-generating substrate further downstream upon insertion of the heating element of the aerosol-generating device into the aerosol-generating 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.

In addition or alternatively, the distance between the ventilation zone and the upstream end of the aerosol generating article is preferably at least about 12 millimeters. More preferably, the distance between the ventilation zone and the upstream end of the aerosol generating article is 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.

The distance between the ventilation zone and the downstream end of the aerosol generating substrate rod is typically at least about 2 millimeters. Preferably, the distance between the ventilation zone and the downstream end of the aerosol generating substrate rod is at least about 4 millimeters. More preferably, the distance between the ventilation zone and the downstream end of the aerosol generating substrate rod is at least about 5 millimeters. Even more preferably, the distance between the ventilation zone and the downstream end of the aerosol generating substrate rod is at least about 10 millimeters. In some particularly preferred embodiments, the distance between the ventilation zone and the downstream end of the aerosol generating substrate rod may be at least about 15 millimeters.

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

In practice, the ventilation zone divides the cavity formed by the hollow tubular segment within it into an upstream subcavity that extends longitudinally from the upstream end of the hollow tubular segment to the location of the ventilation zone, and a downstream subcavity which extends longitudinally from the location of the ventilation zone to the downstream end of the hollow tubular segment. Without being limited by theory, it is understood that in the upstream subcavity, evaporated compounds from the aerosol stream move along the hollow tubular segment and slowly cool, releasing some heat into the peripheral wall of the hollow tubular segment, and thus aerosol particles begin to nucleate. On the other hand, in the downstream subcavity, the aerosol flow and ventilation air quickly mix, which causes rapid cooling of the evaporated compounds from the aerosol flow and, thus, promotes the nucleation of new aerosol particles and the growth of existing aerosol particles as the aerosol moves towards the mouthpiece end of the product.

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

In addition 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.

Likewise, 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 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 2. Even more preferably, the ratio between the length of the upstream section of the aerosol generating article is less than 2. and the length of the downstream section of the aerosol generating product is less than 1.5. In particularly preferred embodiments, 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.

In addition 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.

The aerosol generating products of the present invention are advantageously simple to adjust and control the overall RTD of the product. The reason for this is that the overall RTD of the product depends on the RTD of a finite number of components, and the reduction of the overall RTD of the product is also facilitated by providing a ventilation zone. Therefore, it is possible to advantageously reduce the variability of RTD between aerosol-generating products.

Accordingly, the present invention can also provide a stack containing ten or more of the above-described aerosol generating articles, in which the difference between the RTD of the aerosol generating article which has the highest RTD among at least ten aerosol generating articles and the RTD of the aerosol generating article which has the lowest RTD among at least ten aerosol generating products of less than 10 mmH2O. Art. (approximately 100 pascals). Preferably, in one such stack, the difference between the RTD of the aerosol generating article having the highest RTD among the at least ten aerosol generating articles and the RTD of the aerosol generating article having the lowest RTD among the at least ten aerosol generating articles is less than 9 mm water Art. (approximately 90 pascal), more preferably less than 8 mm of water. Art. (approximately 80 pascal), even more preferably less than 7 mm of water. Art. (approximately 70 pascals).

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

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

in fig. 2 is a schematic side cross-sectional view of another example of an aerosol generating article in accordance with the present invention;

in fig. 3 is a schematic side cross-sectional view of a further example of an aerosol generating article in accordance with the present invention.

The aerosol generating article 10, which is shown in FIG. 1, comprises an aerosol generating substrate rod 12, a hollow cellulose acetate tube 14, a hollow tubular segment 16, and a mouthpiece segment 18. These four elements are end-to-end, longitudinally aligned, and surrounded by a wrapper 20 to form the aerosol generating article 10. The aerosol generating article 10 has a mouthpiece end 22 and an upstream distal end 24 located at the end of the article opposite the mouthpiece end 22. The aerosol generating article 10 shown in FIG. 1 is particularly suitable for use with an electrical aerosol generating device comprising a heater for heating the aerosol generating substrate rod.

The rod of the aerosol generating substrate 12 has a length of approximately 12 millimeters and a diameter of approximately 7 millimeters. The rod 12 is cylindrical in shape and has a substantially circular cross-section. The rod 12 contains a collected sheet of homogenized tobacco material. The homogenized tobacco sheet contains 10 percent by weight, on a dry weight basis, glycerin. The hollow cellulose acetate tube 14 is approximately 8 millimeters long and approximately 1 millimeter thick.

The die segment 18 contains a rod of cellulose acetate tow with a density of 8 denier per fiber and has a length of approximately 7 millimeters.

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

In more detail, the hollow tubular segment 16 may be formed, for example, from paper having a basis weight of 110 g/m ² and a weight of 45 milligrams (ie, 2.5 milligrams/mm length). The equivalent inner diameter of the hollow tubular segment 16 is approximately 7 millimeters. Thus, the volume of the cavity formed by the hollow tubular segment 16 within it is approximately 693 cubic millimeters. Thus, the ratio between the weight of the hollow tubular segment and the volume of the internal cavity formed by the hollow tubular segment 16 is approximately 0.065.

The aerosol generating article 10 includes a ventilation zone 26 at a distance of approximately 5 millimeters from the upstream end of the mouthpiece segment 18. Thus, the ventilation zone 26 is located at a distance of approximately 12 millimeters from the downstream end of the aerosol generating article. and at a distance of approximately 13 millimeters from the upstream end of the hollow tubular segment. Thus, the ventilation zone 26 is located at a distance of approximately 21 millimeters from the downstream end of the rod 12.

In fig. 2 shows another example of an aerosol generating article according to the present invention. The aerosol generating article 30, which is shown in FIG. 2 has the same structure as the aerosol generating article 10 shown in FIG. 1, and differs from the aerosol generating article 10 essentially only in the length of some components, and will be described below only to the extent that it differs from the aerosol generating article 10. In the following, for corresponding components having the same structural or functional function, the same reference numerals will be used whenever possible.

In the aerosol generating article 30, which is shown in FIG. 2, the rod 12 and the hollow cellulose acetate tube 14 have the same length as in the aerosol generating article 10 shown in FIG. 1. However, the die segment includes an 11 denier cellulose acetate tow rod that is approximately 12 millimeters in length, and a hollow tubular segment 16 that is approximately 13 millimeters in length. The ventilation zone 26 is provided at a distance of approximately 6 millimeters from the upstream end of the mouthpiece segment 18 and approximately 7 millimeters from the upstream end of the hollow tubular segment. Thus, the ventilation zone 26 is located at a distance of approximately 15 millimeters from the downstream end of the rod 12.

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

The equivalent inner diameter of the hollow tubular segment 16 may be approximately 5.3 millimeters. Thus, the volume of the cavity formed by the hollow tubular segment 16 within it is approximately 397 cubic millimeters. Thus, the ratio between the weight of the hollow tubular segment and the volume of the internal cavity formed by the hollow tubular segment 16 is approximately 0.43. In fig. 3 illustrates another example of an aerosol generating article according to the present invention. The aerosol generating article 40, which is shown in FIG. 3 is structurally different from the aerosol generating article 10 shown in FIG. 1 and the aerosol generating article 30 which is shown in FIG. 2, in that it does not contain a hollow cellulose acetate tube as a support element. Accordingly, the lengths of the three main components also differ. In the following, for corresponding components having the same structural or functional function, the same reference numerals will be used whenever possible.

In the aerosol generating article 40, which is shown in FIG. 3, the rod 12 has a length of approximately 12 millimeters, the hollow tubular segment 16 has a length of approximately 26 millimeters, and the die segment 18 containing the cellulose acetate tow rod has a length of approximately 12 millimeters and a density of 11 denier per fiber. The ventilation zone 26 is provided at a distance of approximately 5 millimeters from the upstream end of the mouthpiece segment 18 and approximately 21 millimeters from the upstream end of the hollow tubular segment, which in this embodiment coincides with the downstream end of the rod 12.

The following example records experimental results obtained from tests performed on a particular embodiment of an aerosol generating article according to the present invention. Smoking conditions and technical characteristics of the smoking machine are set out in the ISO 3308 standard (ISO 3308:2000). Atmospheric conditions for preparation and testing are specified in ISO 3402.

EXAMPLE 1 This experiment was performed to evaluate the effect of including a hollow tubular segment wherein a ventilation zone is provided at a location along the hollow tubular segment according to the present invention. The experiment examined the effect of the degree of ventilation on the delivery of nicotine and a substance for the formation of an aerosol (glycerol). A comparative measurement with a reference aerosol generating product without ventilation is also presented.

Materials and methods

Product A is an aerosol-generating article that is formed from: an aerosol-generating substrate rod that contains an assembled sheet of homogenized tobacco material and approximately 18 percent, by dry weight, glycerin, the rod having a length of 12 millimeters; a support member in the form of a hollow cellulose acetate tube aligned with the rod and located immediately downstream of the rod, the support member having a length of 8 millimeters; a hollow tubular segment in the form of a cardboard tube aligned with the rod and located immediately downstream of the rod, the hollow tubular segment having a length of 13 millimeters; and a mouthpiece segment of filter material aligned with the hollow tubular segment and located immediately downstream of the hollow tubular segment, the mouthpiece segment having a length of 12 millimeters. The ventilation zone is provided at a location along the hollow tubular segment at a distance of 18 millimeters from the downstream end of the mouthpiece segment. The ventilation rate of aerosol-generating product A is 30 percent.

Product B is a reference aerosol generating product that has the same design as Product A but without a vent area. Thus, the ventilation rate of aerosol-generating article B is 0 percent.

Nicotine and glycerol delivery values were measured by gas chromatography/time of flight mass spectrometry (GC/MS-TOF) on nicotine and glycerol collected on a Cambridge filter pad. The cycles were performed as described in example 1.

Results. The average nicotine and glycerol delivery values from Product A and Product B are shown in Table 1 below.

Table 1. Effect of ventilation degree on nicotine and glycerol delivery values.

Ventilation Nicotine delivery Glycerol [%] (mg) (mg) Product A thirty 1.41 5.6 Product B 0 1.17 3.5

Claims (59)

1. An aerosol generating article for producing an inhalable aerosol when heated, wherein the aerosol generating article contains: a substrate rod for generating an aerosol; a hollow tubular segment at a location downstream of the rod, the hollow tubular segment being longitudinally aligned with the rod, the hollow tubular segment defining a cavity extending the entire length from the upstream end of the hollow tubular segment to the downstream end of the hollow tubular segment flow of the end of the hollow tubular segment; a mouthpiece segment at a location downstream of the hollow tubular segment, the mouthpiece segment comprising a filter material rod and a recess at a mouthpiece end downstream of the filter material rod; And a venting zone at a location along the hollow tubular segment less than 20 millimeters from a downstream end of the aerosol generating article, the venting zone comprising one or more rows of perforations formed through a peripheral wall of the hollow tubular segment; wherein the hollow tubular segment has a length of 25 millimeters; wherein the ratio between the weight of the hollow tubular segment and the volume of the internal cavity formed by the hollow tubular segment is preferably less than 1 milligram/cubic millimeter; and wherein the aerosol generating substrate rod contains at least an aerosol generating agent, wherein the aerosol generating agent content of the aerosol generating substrate rod is at least 12 percent on a dry weight basis. 2. The article of claim 1, wherein the hollow tubular segment includes a wrapper, the wrapper also surrounding the rod. 3. The article of claim 1, wherein the hollow tubular segment comprises a tube formed from a polymeric material or a cellulosic material, the heated aerosol generating article further comprising a wrapper surrounding the rod and the tube. 4. The article according to any of the preceding claims, wherein the ratio between the weight of the hollow tubular segment and the volume of the internal cavity formed by the hollow tubular segment is less than 0.5 milligrams/cubic millimeter. 5. The article according to any of the preceding claims, wherein the ratio between the weight of the hollow tubular segment and the volume of the internal cavity formed by the hollow tubular segment is less than 0.2 milligrams/cubic millimeter. 6. The article according to any of the previous claims, wherein the internal equivalent diameter of the hollow tubular segment at the location of the ventilation zone is at least 5 millimeters. 7. The article according to any of the previous claims, wherein the equivalent internal diameter of the hollow tubular segment at the location of the ventilation zone is at least 5.25 millimeters. 8. The article according to any of the previous claims, wherein the equivalent internal diameter of the hollow tubular segment at the location of the ventilation zone is at least 6 millimeters. 9. The article according to any of the previous claims, wherein the equivalent internal diameter of the hollow tubular segment at the location of the ventilation zone is at least 6.5 millimeters. 10. Product according to any one of paragraphs. 1-5, wherein the internal equivalent diameter of the hollow tubular segment at the location of the ventilation zone is less than 9 millimeters. 11. An article as claimed in any one of the preceding claims, wherein the mouthpiece segment comprises a hollow mouthpiece tube that defines a recess at the mouthpiece end, the hollow mouthpiece tube being longitudinally aligned with the filter material rod and positioned immediately downstream of the it, with the recess open to the external environment at the downstream end of the mouthpiece segment and the aerosol generating article. 12. The article according to any of the preceding claims, wherein the peripheral wall thickness of the hollow tubular segment is less than 1500 micrometers. 13. The article according to any of the preceding claims, wherein the peripheral wall thickness of the hollow tubular segment is less than 1250 micrometers. 14. The article according to any of the preceding claims, wherein the peripheral wall thickness of the hollow tubular segment is less than 1000 micrometers. 15. The article according to any of the preceding claims, wherein the peripheral wall thickness of the hollow tubular segment is less than 900 micrometers. 16. The article according to any of the preceding claims, wherein the peripheral wall thickness of the hollow tubular segment is less than 800 micrometers. 17. Product according to any one of paragraphs. 1-11, wherein the peripheral wall thickness of the hollow tubular segment is at least 100 micrometers. 18. Product according to any one of paragraphs. 1-11, wherein the peripheral wall thickness of the hollow tubular segment is at least 200 micrometers. 19. The product according to any of the previous paragraphs, in which the tightening resistance of the aerosol generating product is from 30 millimeters of water. Art. up to 90 millimeters of water. Art. 20. The product according to claim 19, in which the tightening resistance of the aerosol generating product is from 30 millimeters of water. Art. up to 80 millimeters of water. Art. 21. The product according to claim 19, in which the tightening resistance of the aerosol generating product is from 30 millimeters of water. Art. up to 70 millimeters of water. Art. 22. The product according to claim 19, in which the tightening resistance of the aerosol generating product is from 40 millimeters of water. Art. up to 90 millimeters of water. Art. 23. The product according to claim 19, in which the tightening resistance of the aerosol generating product is from 50 millimeters of water. Art. up to 90 millimeters of water. Art. 24. An article according to any of the previous paragraphs, having a ventilation rate of at least 20 percent. 25. An article according to any of the previous paragraphs, having a ventilation rate of at least 30 percent. 26. An article according to any of the previous paragraphs, having a ventilation rate of at least 35 percent. 27. Product according to any of the previous claims, wherein the distance between the ventilation zone and the upstream end of the hollow tubular segment is at least 6 millimeters. 28. The product according to any of the previous claims, wherein the distance between the ventilation zone and the upstream end of the aerosol generating product is at least 12 millimeters. 29. The product according to any of the previous claims, wherein the distance between the ventilation zone and the upstream end of the aerosol generating product is at least 20 millimeters. 30. The product according to any of the previous claims, wherein the distance between the ventilation zone and the upstream end of the aerosol generating product is at least 25 millimeters. 31. The product according to any of the previous claims, wherein the distance between the ventilation zone and the downstream end of the aerosol generating product is at least 2 millimeters. 32. The product according to any of the previous claims, wherein the distance between the ventilation zone and the downstream end of the aerosol generating product is at least 4 millimeters. 33. The product according to any of the previous claims, wherein the distance between the ventilation zone and the downstream end of the aerosol generating product is at least 5 millimeters. 34. An article according to any of the preceding claims, wherein the distance between the ventilation zone and the downstream end of the aerosol generating article is at least 10 millimeters. 35. The product according to any of the previous claims, wherein the distance between the ventilation zone and the downstream end of the aerosol generating product is at least 15 millimeters. 36. The article according to any of the preceding claims, wherein the ratio between the distance from the ventilation zone to 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 4. 37. The article according to any of the preceding claims, wherein the ratio between the distance from the ventilation zone to 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. 38. The article according to any of the preceding claims, wherein the ratio between the distance from the ventilation zone to 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. 39. The article according to any of the preceding claims, wherein the ratio between the distance from the ventilation zone to 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 2.5. 40. The article according to any of the preceding claims, wherein the ratio between the distance from the ventilation zone to 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 2. 41. The article according to any of the preceding claims, wherein the ratio between the distance from the ventilation zone to 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 1.5. 42. The article according to any of the preceding claims, wherein the ratio between the distance from the ventilation zone to 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 1.2. 43. An article as claimed in any one of the preceding claims, wherein the outer diameter of the aerosol generating substrate rod is between 6 millimeters and 8 millimeters. 44. The article of any one of the preceding claims, wherein the ventilation zone comprises two rows of perforations formed through a peripheral wall of the hollow tubular segment, the rows of perforations being spaced apart from each other in the longitudinal direction along the hollow tubular segment. 45. An article as claimed in any one of the preceding claims, wherein the aerosol generating agent content of the aerosol generating substrate rod is at least 14 percent by dry weight. 46. An article according to any of the preceding claims, wherein the aerosol generating substrate rod has a length of at least 10 millimeters. 47. Product according to any one of paragraphs. 1-45, in which the aerosol generating substrate rod has a length of less than 65 millimeters. 48. Product according to any one of paragraphs. 1-45, in which the aerosol generating substrate rod has a length of less than 50 millimeters. 49. An article as claimed in any one of the preceding claims, wherein the aerosol generating substrate rod comprises tobacco material. 50. The article of claim 49, wherein the aerosol generating substrate rod contains pieces, strands or strips of tobacco material. 51. The article of claim 49, wherein the aerosol generating substrate rod comprises one or more assembled sheets of tobacco material. 52. The article of claim 49, wherein the aerosol generating substrate rod comprises strands of homogenized tobacco material formed by casting, rolling, calendering or extruding a mixture containing bulk tobacco and at least one aerosol generating agent to form a homogenized tobacco sheet material. 53. The product of any one of the preceding claims, wherein the aerosol generating substrate rod comprises a non-tobacco based nicotine-containing material.

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