Aerosol-generating article with low-resistance airflow path

Abstract

To provide a heated aerosol-generating article for use with an aerosol-generating device that is designed to be difficult to light in the manner of traditional cigarettes.SOLUTION: A heated aerosol-generating article (10) comprises a plurality of components, including an aerosol-forming substrate (20), assembled within a wrapper (60) to form a rod having a mouth end (70) and a distal end (80) upstream from the mouth end (70). The heated aerosol-generating article (10) defines a first air-flow path in which air drawn into the aerosol-generating article (10) through the mouth end (70) passes through the aerosol-forming substrate (20), and a second air-flow path in which air drawn into the aerosol-generating article (10) through the mouth end (70) does not pass through the aerosol-forming substrate (20). The resistance to draw (RTD) of the second air-flow path is lower than the RTD of the first air-flow path when the heated aerosol-generating article (10) is not coupled to an aerosol-generating device.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This specification relates to an aerosol-generating article comprising an aerosol-forming substrate for generating an inhalable aerosol when heated using an aerosol-generating device. When not engaged by an aerosol-generating device, the aerosol-generating article defines a low resistance airflow path that does not pass through the aerosol-forming substrate. This specification also relates to a method of using such an aerosol-generating article. [Background technology]

[0002] Aerosol-generating articles in which an aerosol-forming substrate, such as a tobacco-containing substrate, is heated rather than combusted are well known in the art. One purpose of such heated aerosol-generating articles is to reduce the well-known harmful smoke components produced by the combustion and pyrolysis of tobacco in conventional cigarettes.

[0003] A conventional cigarette is lit when a user applies a flame to one end of the cigarette and draws air through the other end. Localized heat provided by the flame and oxygen in the air drawn through the cigarette ignites the end of the cigarette, and the resulting combustion produces inhalable smoke. In contrast, in heated aerosol-generating articles, the inhalable aerosol is typically generated by heat transfer to an aerosol-forming substrate or material that is physically separate from the heat source, which may be located in, around, or downstream of the heat source. During consumption, volatile compounds are released from the aerosol-forming substrate by heat transfer from the heat source and are entrained in the air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol that is inhaled by the consumer.

[0004] Heated aerosol-generating articles, including tobacco, for generating an aerosol by heating rather than combustion are well known in the art. For example, WO2013 / 102614 discloses an aerosol generating system comprising an aerosol generating device having a heated aerosol-generating article and a heater for heating the heated aerosol-generating article to generate an aerosol.

[0005] Tobacco used as part of the aerosol-forming substrate in heated aerosol-generating articles is designed to generate aerosol when heated, not when burned. Thus, such tobacco generally contains high levels of aerosol-forming agents, such as glycerin or propylene glycol. If a user were to light the heated aerosol-generating article and smoke it as if it were a traditional cigarette, the user would not have the intended user experience. It would be desirable to produce heated aerosol-generating articles that have low or no tendency to flame ignition. Preferably, such heated aerosol-generating articles are difficult to ignite when an attempt is made to light the article with a lighter (e.g., a flame) in the manner of a traditional cigarette. Summary of the Invention

[0006] A heated aerosol-generating article may be provided for use with an aerosol-generating device. The heated aerosol-generating article may comprise a number of components including an aerosol-forming substrate assembled within a wrapper to form a rod having an oral end and a distal end upstream of the oral end. The heated aerosol-generating article defines a first potential airflow path in which air drawn into the aerosol-generating article through the oral end passes through the aerosol-forming substrate, and a second potential airflow path in which air drawn into the aerosol-generating article through the oral end does not pass through the aerosol-forming substrate. When the heated aerosol-generating article is not coupled to the aerosol-generating device, the resistance of draw (RTD) of the second airflow path is less than the RTD of the first airflow path. The second airflow path has a low resistance compared to the first airflow path.

[0007] When the heated aerosol-generating article is not coupled to an aerosol-generating device, the preferred airflow path for air drawn into the heated aerosol-generating article through the mouth end is the second airflow path. Thus, when a user draws on the mouth end of the heated aerosol-generating article without engaging the heated aerosol-generating article with an aerosol-generating device, substantially no air is drawn through the aerosol-forming substrate. When a user attempts to ignite the heated aerosol-generating article in the same manner as a conventional cigarette, i.e., by bringing a flame close to the distal end of the rod, and draws on the mouth end, substantially no air flows through the aerosol-forming substrate. This lack of airflow makes it difficult to ignite the aerosol-forming substrate.

[0008] The heated aerosol-generating article may have a low effective resistance to draw (RTD) when not connected to an aerosol-generating device. For example, the effective RTD may be close to zero. This may prevent a user from drawing enough air through the aerosol-forming substrate to ignite the aerosol-forming substrate. The second airflow path may be any airflow path that prevents sufficient air flow through the aerosol-forming substrate to prevent self-sustaining combustion of the substrate when attempting to ignite the article.

[0009] The interaction between the heated aerosol-generating article and the aerosol-generating device preferably increases the RTD along the second airflow path, such that air flow along the first airflow path is preferred. The engagement of the heated aerosol-generating article with the aerosol-generating device may partially or completely block the second airflow path, such that the second airflow path is of higher resistance than the first airflow path. Thus, air drawn through the heated aerosol-generating article may preferentially flow along the first airflow path through the aerosol-forming substrate.

[0010] The aerosol-forming substrate of the heated aerosol-generating article may be located at or towards the distal end of the rod. One or more holes or perforations defined through the wrapper downstream of the aerosol-forming substrate may define part of the second airflow path. Thus, when the heated aerosol-generating article is not engaged with the aerosol-generating device, the airflow path of least resistance is one that enters the article through the holes or perforations in the wrapper downstream of the aerosol-forming substrate. Air flowing into the article through this path is then drawn out through the mouth end of the rod and does not flow over or through the aerosol-forming substrate.

[0011] The wrapper is preferably a highly perforated wrapper that allows air to be drawn through the wrapper downstream of the aerosol-forming substrate to the heated aerosol-generating article. A perforated wrapper can reduce the RTD of the heated aerosol-generating article to nearly zero.

[0012] A support element, such as a hollow acetate tube, may be located downstream of the aerosol-forming substrate. Radially extending holes may be defined through the radial walls of the support element that form part of the second airflow path. Such holes are preferably large enough to reduce the RTD of the heated aerosol-generating article to approximately zero. A wrapper may define holes that overlap the radially extending holes. Alternatively, the wrapper may be a highly perforated wrapper.

[0013] In a preferred embodiment, the aerosol-forming substrate is in the form of an aerosol-generating rod comprising at least one aggregate of a sheet of material. The aggregate of a sheet of material may be a sheet of homogenized tobacco. The aerosol-forming substrate may be a rod of aggregate tobacco as described in WO 2012 / 164009.

[0014] The heated aerosol generating system may comprise a heated aerosol-generating article according to any one of the embodiments described above and an aerosol generating device including means for heating the aerosol-forming substrate, the aerosol generating device being arranged to engage the heated aerosol-generating article such that when a user inhales on the oral end of the rod, the second airflow path is interrupted and air is drawn through the aerosol-forming substrate.

[0015] Preferably, engagement of the heated aerosol-generating device with the aerosol-generating article increases the resistance along the second airflow path, and therefore the preferred airflow path is the first airflow path through the aerosol-forming substrate.

[0016] The aerosol-generating device may define a chamber for receiving the aerosol-generating article. The chamber may seal at least a portion of the outer surface of the aerosol-generating article sufficiently to increase resistance to or completely prevent airflow along the second airflow path. The device allows air to pass through the aerosol-forming substrate when the heated aerosol-generating article is engaged with the aerosol-generating device. The aerosol-generating device may interact with the aerosol-generating article to seal one or more airflow holes or perforations defined in the aerosol-generating article.

[0017] The aerosol-generating device includes means for heating the aerosol-forming substrate of the aerosol-generating article. Such means may comprise, for example, a heating element, such as a heating element insertable into the aerosol-generating article or a heating element that may be positioned adjacent to the aerosol-generating article. The heating means may comprise an inductor, such as, for example, an induction coil, for interacting with the susceptor.

[0018] A method of smoking or consuming an aerosol-generating article as described herein may include engaging the heated aerosol-generating article with an aerosol-generating device such that the second airflow path is interrupted, activating the aerosol-generating device to heat the aerosol-forming substrate, and drawing on the mouth end of the rod to flow along the first airflow path, wherein the aerosol generated by heating the aerosol-forming substrate is entrained in air as it passes through the aerosol-forming substrate.

[0019] As used herein, the term "aerosol-forming substrate" is used to describe a substrate capable of releasing, upon heating, a volatile compound capable of forming an aerosol. The aerosol generated from the aerosol-forming substrate of the aerosol-generating articles described herein may or may not be visible and may include vapor (e.g., fine particles of a substance that is normally a liquid or solid at room temperature in a gaseous state) as well as liquid droplets of the gas and condensed vapor.

[0020] As used herein, the terms "upstream" and "downstream" are used to describe the relative position of an element or portion of an element of a heated aerosol-generating article with respect to the direction in which a user draws on the aerosol-generating article during use thereof.

[0021] The heated aerosol-generating article includes two ends, a proximal end through which the aerosol exits the aerosol-generating article, and a distal end through which the aerosol is delivered to a user. In use, a user may draw on the proximal end to inhale the aerosol generated by the aerosol-generating article.

[0022] The proximal end may also be referred to as the oral end or downstream end and is downstream of the distal end, and the distal end may also be referred to as the upstream end and is upstream of the proximal end.

[0023] As used herein, the term "aerosol cooling element" is used to describe an element that has a large surface area and low draw resistance. In use, the aerosol formed by the volatile compounds released from the aerosol-forming substrate passes through and is cooled by the aerosol cooling element before being inhaled by the user. In contrast to high draw resistance filters and other mouthpieces, the aerosol cooling element has a low draw resistance. Also, chambers and cavities within the aerosol-generating article are not considered to be aerosol cooling elements.

[0024] The heated aerosol-generating article is preferably a smoking article that generates an aerosol that can be inhaled directly through the user's mouth into the user's lungs.Furthermore, the heated aerosol-generating article is preferably a smoking article that generates a nicotine-containing aerosol that can be inhaled directly through the user's mouth into the user's lungs.

[0025] As used herein, the term "aerosol-generating device" is used to describe a device that interacts with an aerosol-forming substrate of an aerosol-generating article to generate an aerosol. The aerosol-generating device is preferably a smoking device that interacts with an aerosol-forming substrate of a heated aerosol-generating article to generate an aerosol that is inhalable directly through the user's mouth into the user's lungs. The aerosol-generating device preferably interacts with the aerosol-generating article to cause air to flow through the aerosol-forming substrate.

[0026] For the avoidance of doubt, in the following description the term "heating element" is used to mean one or more heating elements.

[0027] In a preferred embodiment, the aerosol-forming substrate is located at the upstream end of the aerosol-generating article.

[0028] As used herein, the term "diameter" is used to describe the maximum lateral dimension of the aerosol-generating article. As used herein, the term "length" is used to describe the maximum longitudinal dimension of the aerosol-generating article.

[0029] The aerosol-forming substrate is preferably a solid aerosol-forming substrate. The aerosol-forming substrate may comprise solid and liquid components.

[0030] Preferably, the aerosol-forming substrate comprises nicotine, more preferably, the aerosol-forming substrate comprises tobacco.

[0031] Alternatively, or additionally, the aerosol-forming substrate may comprise a non-tobacco material comprising an aerosol-forming material.

[0032] Where the aerosol-forming substrate is a solid aerosol-forming substrate, the solid aerosol-forming substrate may comprise, for example, one or more of powders, granules, pellets, shreds, threads, strips or sheets including one or more of herb leaves, tobacco leaves, tobacco stems, expanded tobacco and homogenized tobacco.

[0033] Optionally, the solid aerosol-forming substrate may contain tobacco or non-tobacco volatile flavour compounds, which are released in response to heating of the solid aerosol-forming substrate. The solid aerosol-forming substrate may also contain one or more capsules, for example, containing additional tobacco or non-tobacco volatile flavour compounds, which may dissolve during heating of the solid aerosol-forming substrate.

[0034] Optionally, the solid aerosol-forming substrate may be provided on or embedded in a thermally stable carrier. The carrier may take the form of a powder, granules, pellets, pieces, threads, strips or sheets. The solid aerosol-forming substrate may be deposited on the surface of the carrier, for example in the form of a sheet, foam, gel or slurry. The solid aerosol-forming substrate may be deposited on the entire surface of the carrier, or alternatively, may be deposited in a pattern to provide a non-uniform flavor delivery during use.

[0035] In a preferred embodiment, the aerosol-forming substrate comprises homogenized tobacco material.

[0036] As used herein, the term "homogenized tobacco material" refers to a material formed by agglomerating particulate tobacco.

[0037] The aerosol-forming substrate preferably comprises an assemblage of sheets of homogenised tobacco material.

[0038] As used herein, the term "sheet" means a laminar element having a width and length that are substantially greater than its thickness.

[0039] As used herein, the term "collected" is used to describe a sheet that is rolled, folded, or otherwise compressed or contracted substantially transverse to the longitudinal axis of the aerosol-generating article.

[0040] The use of an aerosol-forming substrate comprising an aggregated sheet of homogenized tobacco material advantageously significantly reduces the risk of "loose ends" compared to aerosol-forming substrates comprising fragments of tobacco material (i.e., loss of fragments of tobacco material from the ends of the rod), which can disadvantageously lead to the need for more frequent cleaning of aerosol-generating devices and manufacturing equipment for use with the aerosol-generating article.

[0041] In a preferred embodiment, the aerosol-forming substrate comprises an assemblage of textured sheets of homogenized tobacco material.

[0042] As used herein, the term "textured sheet" refers to a sheet that has been crimped, embossed, debossed, perforated, or otherwise modified. The aerosol-forming substrate may comprise an assemblage of a textured sheet of homogenized tobacco material that contains a plurality of spaced indentations, protrusions, perforations, or combinations thereof.

[0043] In a particularly preferred embodiment, the aerosol-forming substrate comprises an assemblage of crimped sheets of homogenized tobacco material.

[0044] The use of a textured sheet of homogenized tobacco material may advantageously facilitate consolidation of the sheet of homogenized tobacco material to form the aerosol-forming substrate.

[0045] As used herein, the term "crimped sheet" refers to a sheet having a plurality of substantially parallel ridges or wrinkles. The substantially parallel ridges or wrinkles preferably extend along or parallel to the longitudinal axis of the aerosol-generating article when the aerosol-generating article is assembled. This conveniently facilitates assembly of the crimped sheet of homogenized tobacco material to form an aerosol-forming substrate. However, it is recognized that a crimped sheet of homogenized tobacco material for inclusion in an aerosol-generating article may alternatively or additionally have a plurality of substantially parallel ridges or wrinkles that are disposed at an acute or obtuse angle to the longitudinal axis of the aerosol-generating article when the aerosol-generating article is assembled.

[0046] In certain embodiments, the aerosol-forming substrate may comprise an assemblage of a sheet of homogenized tobacco material that is substantially uniformly textured over substantially its entire surface. For example, the aerosol-forming substrate may comprise an assemblage of a crimped sheet of homogenized tobacco material that includes a plurality of substantially parallel ridges or corrugations that are substantially uniformly spaced across the width of the sheet.

[0047] The aerosol-forming substrate may be in the form of a plug comprising the aerosol-forming material surrounded by a paper or other wrapper. When the aerosol-forming substrate is in the form of a plug, the entire plug, including any wrapper, is considered to be the aerosol-forming substrate.

[0048] In one preferred embodiment, the aerosol-generating substrate comprises a plug comprising an assemblage of a textured sheet of homogenized tobacco material surrounded by a wrapper. In a particularly preferred embodiment, the aerosol-generating substrate comprises a plug comprising an assemblage of a crimped sheet of homogenized tobacco material surrounded by a wrapper.

[0049] In certain embodiments, sheets of homogenized tobacco material for use in aerosol-generating substrates may have a tobacco content of approximately 70% or more by weight on a dry mass basis.

[0050] A sheet of homogenized tobacco material for use in an aerosol-generating substrate may include one or more intrinsic binders, one or more extrinsic binders, or combinations thereof, to assist in agglomerating particulate tobacco. Alternatively, or in addition, a sheet of homogenized tobacco material for use in an aerosol-generating substrate may include other additives, including, but not limited to, tobacco and non-tobacco fibers, aerosol formers, humectants, plasticizers, flavorants, fillers, aqueous and non-aqueous solvents, and combinations thereof.

[0051] Suitable extrinsic binders for inclusion in sheets of homogenized tobacco material for use in aerosol-generating substrates are well known in the art and include, but are not limited to, gums such as guar gum, xanthan gum, gum arabic, and locust bean gum; cellulosic binders such as hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, and ethyl cellulose; polysaccharides such as starch, organic acids such as alginic acid, sodium alginate, conjugate base salts of organic acids such as agar and pectin; and combinations thereof.

[0052] Suitable non-tobacco fibers for inclusion in a sheet of homogenized tobacco material for use in an aerosol-generating substrate are well known in the art and include, but are not limited to, cellulose fibers, soft wood fibers, hard wood fibers, jute fibers, and combinations thereof. Prior to inclusion in a sheet of homogenized tobacco material for use in an aerosol-generating substrate, the non-tobacco fibers may be treated by any suitable process known in the art, including, but not limited to, mechanical pulping, refining, chemical pulping, bleaching, sulfate pulping, and combinations thereof.

[0053] Sheets of homogenized tobacco material for use in aerosol-generating substrates must have a sufficiently high tensile strength to survive consolidation to form the aerosol-generating substrate, In certain embodiments, sheets of homogenized tobacco material for use in aerosol-generating substrates may include non-tobacco fibers to achieve suitable tensile strength.

[0054] For example, a sheet of homogenized tobacco material for use in an aerosol-generating substrate may contain between about 1% and about 5% non-tobacco fibers by weight on a dry mass basis.

[0055] The aerosol-forming substrate preferably comprises an aerosol-forming agent.

[0056] As used herein, the term "aerosol forming agent" is used to describe any suitable known compound or mixture of compounds that, in use, facilitates the formation of an aerosol and is substantially resistant to thermal decomposition at the use temperature of the aerosol-generating article.

[0057] Suitable aerosol forming agents are well known in the art and include, but are not limited to, polyhydric alcohols (such as propylene glycol, triethylene glycol, 1,3-butanediol, and glycerin), esters of polyhydric alcohols (such as glycerol mono-, di-, or triacetate), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate and dimethyl tetradecanedioate).

[0058] Preferred aerosol forming agents are polyhydric alcohols or mixtures thereof such as propylene glycol, triethylene glycol, 1,3-butanediol and most preferably glycerin.

[0059] The aerosol-forming substrate may comprise a single aerosol-forming agent, or alternatively, the aerosol-forming substrate may comprise a combination of two or more aerosol-forming agents.

[0060] The aerosol-forming substrate preferably has an aerosol-forming agent content of greater than 5% on a dry weight basis.

[0061] The aerosol-forming substrate may have an aerosol-forming agent content of between about 5% and about 30% on a dry weight basis.

[0062] In a preferred embodiment, the aerosol-forming substrate has an aerosol-forming agent content of approximately 20% on a dry weight basis.

[0063] Aerosol-forming substrates comprising an aggregate of homogenized tobacco sheets for use in aerosol-generating articles may be manufactured by methods well known in the art, for example as disclosed in WO 2012 / 164009 A2.

[0064] In a preferred embodiment, a sheet of homogenized tobacco material for use in an aerosol-generating article is formed from a slurry including particulate tobacco, guar gum, cellulose fibers and glycerin by a casting process.

[0065] The aerosol-forming element preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article.

[0066] The outer diameter of the aerosol-forming substrate is preferably at least 5 millimeters. The aerosol-forming substrate may have an outer diameter of between approximately 5 millimeters and approximately 12 millimeters, for example between approximately 5 millimeters and approximately 10 millimeters, or between approximately 6 millimeters and approximately 8 millimeters. In a preferred embodiment, the aerosol-forming substrate has an outer diameter of 7.2 millimeters + / - 10%.

[0067] The aerosol-forming substrate may have a length between about 7 mm and about 15 mm. In one embodiment, the aerosol-forming substrate may have a length of about 10 mm. In a preferred embodiment, the aerosol-forming substrate has a length of about 12 mm.

[0068] The aerosol-forming substrate is preferably substantially cylindrical.

[0069] For example, a support element, such as a hollow support element, may be located immediately downstream of the aerosol-forming substrate.

[0070] The support element may be formed from any suitable material or combination of materials. For example, the support element may be formed from one or more materials selected from the group consisting of cellulose acetate; cardboard; crimped paper, such as crimped heat-resistant paper or crimped parchment paper; and polymeric materials, such as low-density polyethylene (LDPE). In a preferred embodiment, the support element is formed from cellulose acetate.

[0071] The support element may comprise a hollow tubular element. In a preferred embodiment, the support element comprises a hollow cellulose acetate tube.

[0072] The support element preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article.

[0073] The support element may have an outer diameter of between about 5 millimeters and about 12 millimeters, such as between about 5 millimeters and about 10 millimeters or between about 6 millimeters and about 8 millimeters. In a preferred embodiment, the support element has an outer diameter of 7.2 millimeters + / - 10%.

[0074] The support element may have a length between about 5 mm and about 15 mm. In a preferred embodiment, the support element has a length of about 8 mm.

[0075] The aerosol cooling element may be located downstream of the aerosol-forming substrate, for example in some embodiments the aerosol cooling element may be located immediately downstream of a support element that is downstream of the aerosol-forming substrate.

[0076] The aerosol cooling element may be located between the support element and a mouthpiece located at the extreme downstream end of the aerosol-generating article.

[0077] The aerosol cooling element may have a total surface area of ​​between approximately 300 and 1000 square millimeters per millimeter of length. In a preferred embodiment, the aerosol cooling element has a total surface area of ​​approximately 500 square millimeters per millimeter of length.

[0078] The aerosol cooling element may alternatively be referred to as a heat exchanger.

[0079] The aerosol cooling element preferably has a low resistance to draw, i.e., the aerosol cooling element preferably provides low resistance to the passage of air through the aerosol-generating article, and preferably does not substantially affect the resistance to draw of the aerosol-generating article.

[0080] Preferably, the aerosol cooling element has a porosity in the longitudinal direction of between 50% and 90%. The porosity of the aerosol cooling element in the longitudinal direction is defined by the ratio of the cross-sectional area of ​​the material forming the aerosol cooling element to the internal cross-sectional area of ​​the aerosol-generating article at the location of the aerosol cooling element.

[0081] The aerosol cooling element may include a plurality of longitudinally extending channels. The plurality of longitudinally extending channels may be defined by a sheet of material that is crimped, pleated, gathered, folded, or one or more times to form the channels. The plurality of longitudinally extending channels may be defined by a single sheet that is crimped, pleated, gathered, folded, or one or more times to form the channels. Alternatively, the plurality of longitudinally extending channels may be defined by multiple sheets that are crimped, pleated, gathered, folded, or one or more times to form the channels.

[0082] In some embodiments, the aerosol cooling element may comprise an assembly of sheets of material selected from the group consisting of metal foil, polymeric material, and substantially non-porous paper or cardboard. In some embodiments, the aerosol cooling element may comprise an assembly of sheets of material selected from the group consisting of polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polylactic acid (PLA), cellulose acetate (CA), and aluminum foil.

[0083] The aerosol cooling element may have an outer diameter of between about 5 millimeters and about 10 millimeters, such as between about 6 millimeters and about 8 millimeters. In a preferred embodiment, the aerosol cooling element has an outer diameter of 7.2 millimeters ±10%.

[0084] The aerosol cooling element may have a length between about 5 mm and about 25 mm. In a preferred embodiment, the aerosol cooling element has a length of about 18 mm.

[0085] In some embodiments, the aerosol cooling element may comprise an assembly of sheets of material selected from the group consisting of metal foil, polymeric material, and substantially non-porous paper or cardboard. In some embodiments, the aerosol cooling element may comprise an assembly of sheets of material selected from the group consisting of polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polylactic acid (PLA), cellulose acetate (CA), and aluminum foil.

[0086] In a preferred embodiment, the aerosol cooling element comprises an assembly of sheets of a biodegradable polymeric material such as polylactic acid or Mater-Bi® grades, a commercially available family of starch-based copolyesters.

[0087] In a particularly preferred embodiment, the aerosol cooling element comprises an assembly of sheets of polylactic acid.

[0088] The aerosol-generating article may include a mouthpiece located at a downstream end of the aerosol-generating article.

[0089] The mouthpiece may be located directly downstream of the aerosol cooling element or adjacent to the aerosol cooling element.

[0090] The mouthpiece may include a filter. The filter may be formed from one or more suitable filtering materials. Many such filtering materials are known in the art. In one embodiment, the mouthpiece may include a filter formed from cellulose acetate tow.

[0091] The mouthpiece preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article.

[0092] The mouthpiece may have an outer diameter of between about 5 millimeters and about 10 millimeters, for example between about 6 millimeters and about 8 millimeters. In a preferred embodiment, the mouthpiece has an outer diameter of 7.2 millimeters + / - 10%.

[0093] The mouthpiece may have a length between about 5 millimeters and about 20 millimeters. In a preferred embodiment, the mouthpiece has a length of about 14 millimeters.

[0094] The mouthpiece may have a length between about 5 millimeters and about 14 millimeters. In a preferred embodiment, the mouthpiece has a length of about 7 millimeters.

[0095] The aerosol-forming substrate, and any other components of the heated aerosol-generating article, are assembled within a surrounding wrapper, which may be formed from any suitable material or combination of materials. The outer wrapper is preferably cigarette paper.

[0096] The downstream end portion of the wrapper may be surrounded by a strip of tipping paper.

[0097] The appearance of the heated aerosol generating article may mimic the appearance of a conventional cigarette with a lit end.

[0098] The aerosol-generating article may have an outer diameter of between about 5 millimeters and about 12 millimeters, for example between about 6 millimeters and about 8 millimeters. In a preferred embodiment, the aerosol-generating article has an outer diameter of 7.2 millimeters + / - 10%.

[0099] The aerosol-generating article may have an overall length of between about 30 millimeters and about 100 millimeters. In a preferred embodiment, the aerosol-generating article has an overall length of about 45 millimeters.

[0100] The aerosol generating device may include: a housing; a heating element; a power supply connected to the heating element; and a control element configured to control the supply of power from the power supply to the heating element.

[0101] The housing may define a cavity surrounding the heating element, the cavity being configured to receive the heated aerosol-generating article and interact with the aerosol-generating article to interrupt or close the second airflow pathway such that air is drawn through the aerosol-forming substrate.

[0102] The aerosol generating device is preferably a portable or handheld aerosol generating device that is easily held by a user between the fingers of a single hand.

[0103] The aerosol generating device may be substantially cylindrical in shape.

[0104] The aerosol generating device may have a length between about 70 millimeters and about 120 millimeters.

[0105] The power supply may be any suitable power supply, for example a direct current voltage source such as a battery. In one embodiment, the power supply is a lithium ion battery. Alternatively, the power supply may be a nickel metal hydride battery, a nickel cadmium battery or a lithium-based battery, for example a lithium cobalt, lithium iron phosphate, lithium titanate or lithium polymer battery.

[0106] The control element may be a simple switch, or it may be an electrical circuit and may include one or more microprocessors or microcontrollers.

[0107] The heating element of the aerosol-generating device may be any suitable heating element capable of being inserted into the aerosol-forming substrate of the aerosol-generating article For example, the heating element may be in the form of a pin or blade.

[0108] The heating element may have a tapered, pointed or sharpened end to facilitate insertion of the heating element into the aerosol-forming substrate of the aerosol-generating article.

[0109] The resistance to withdrawal (RTD) of the aerosol-generating article prior to engagement with the aerosol-generating article is preferably close to zero (e.g., less than 10 mmWG). After engagement with the aerosol generating device, the RTD may be from about 80 mmWG to about 140 mmWG, preferably from 110 to 115 mmWG.

[0110] As used herein, withdrawal resistance is expressed in units of pressure "mmWG" or "mm of water gauge" and is measured in accordance with ISO 6565:2002.

[0111] In another aspect, there is provided a heated aerosol-generating article for use with an aerosol-generating device, the heated aerosol-generating article comprising a plurality of components including an aerosol-forming substrate assembled within a wrapper to form a rod having an oral end and a distal end upstream of the oral end, the heated aerosol-generating article defining a first airflow path through which air drawn into the aerosol-generating article through the oral end passes through the aerosol-forming substrate and a second airflow path through which air drawn into the aerosol-generating article through the oral end is drawn through the wrapper and into the rod, wherein the second airflow path merges with the first airflow path at a location downstream of the aerosol-forming substrate, and wherein a resistance to draw (RTD) of the second airflow path through the wrapper is less than the RTD of the first airflow path through the aerosol-forming substrate.

[0112] The RTD of the second airflow path is preferably not more than 0.9 times the RTD of the first airflow path, more preferably 0.2 to 0.7 times the RTD of the first airflow path, and even more preferably 0.3 to 0.5 times the RTD of the first airflow path.

[0113] In a further aspect, there is provided a heated aerosol-generating article for use with an aerosol-generating device, the heated aerosol-generating article comprising a plurality of components including an aerosol-forming substrate assembled within a wrapper to form a rod having an oral end and a distal end upstream of the oral end, the heated aerosol-generating article defining a first airflow path through which air drawn into the aerosol-generating article through the oral end passes through the aerosol-forming substrate and a second airflow path through which air drawn into the aerosol-generating article through the oral end is drawn through the wrapper and into the rod, where the second airflow path merges with the first airflow path at a location downstream of the aerosol-forming substrate, and the aerosol-generating article is configured such that when draw is applied to the oral end of the rod, neither the first nor the second airflow path is blocked and a greater volume of air is drawn through the second airflow path than is drawn through the first airflow path.

[0114] Preferably, the volume of air drawn through the second airflow path is at least twice the volume of air drawn through the first airflow path.

[0115] Also, features described with respect to one aspect or embodiment may be applicable to other aspects and embodiments, for example features described with respect to the aerosol generating articles and aerosol generating systems described above may also be used in conjunction with methods of using the aerosol generating articles and aerosol generating systems described above.

[0116] Specific embodiments will now be described with reference to the figures. [Brief description of the drawings]

[0117] [Figure 1] FIG. 1 is a schematic cross-sectional view of an embodiment of a heated aerosol-generating article for use with an aerosol generating device. [Diagram 2] FIG. 2 is a schematic cross-sectional view of a further embodiment of a heated aerosol-generating article for use with an aerosol generating device. [Diagram 3] FIG. 3 is a schematic cross-sectional view of an embodiment of an aerosol generating system including an electrically heated aerosol generating device including a heating element and an aerosol generating article according to the embodiment illustrated in FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view of the aerosol generating device shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0118] FIG. 1 illustrates a heated aerosol-generating article 10 according to a preferred embodiment. The aerosol-generating article 10 includes four coaxially aligned elements: an aerosol-forming substrate 20, a support element 30, an aerosol cooling element 40, and a mouthpiece 50. These four elements are arranged in series and surrounded by an outer wrapper 60 to form the heated aerosol-generating article 10. The aerosol-generating article 10 has a proximal or oral end 70 that is inserted into the mouth of a user during use, and a distal end 80 at the opposite end of the aerosol-generating article 10 relative to the oral end 70. The outer wrapper 60 is a highly perforated paper that offers little or no resistance to airflow through the paper. A non-perforated tipping paper 65 surrounds the mouthpiece end of the article 10.

[0119] Additionally, the distal end 80 of the aerosol-generating article 10 may be described as the upstream end of the aerosol-generating article 10, and the oral end 70 of the aerosol-generating article 10 may also be described as the downstream end of the aerosol-generating article 10. Elements of the aerosol-generating article 10 located between the oral end 70 and the distal end 80 may be described as being upstream of the oral end 70, or alternatively, downstream of the distal end 80.

[0120] The aerosol-forming substrate 20 is located at the extreme distal or upstream end of the aerosol-generating article 10. In the embodiment illustrated in Figure 1, the aerosol-forming substrate 20 comprises an assembly of a sheet of crimped homogenized tobacco material surrounded by a wrapper. The crimped sheet of homogenized tobacco material includes glycerin as an aerosol-forming agent.

[0121] The support element 30 is located directly downstream of and adjacent to the aerosol-forming substrate 20. In the embodiment shown in FIG. 1, the support element is a hollow cellulose acetate tube. The support element 30 positions the aerosol-forming substrate 20 at the extreme distal end 80 of the aerosol-generating article 10 so that it can be penetrated by a heating element of an aerosol-generating device. The support element 30 also serves to prevent the aerosol-forming substrate 20 from being pushed downstream into the aerosol-generating article 10 towards the aerosol-cooling element 40 when the heating element of the aerosol-generating device is inserted into the aerosol-forming substrate 20. The support element 30 also serves as a spacer that spaces the aerosol-forming substrate 20 from the aerosol-forming substrate 20 and the aerosol-cooling element 40 of the aerosol-generating article 10.

[0122] The aerosol cooling element 40 is located directly downstream of and adjacent to the support element 30. In use, volatile material emitted from the aerosol-forming substrate 20 passes along the aerosol cooling element 40 towards the mouth end 70 of the aerosol-generating article 10. The volatile material may cool within the aerosol cooling element 40 to form an aerosol that is inhaled by the user. In the embodiment illustrated in Figure 1, the aerosol cooling element comprises an assembly of crimped sheets of polylactic acid surrounded by a wrapper 90. The assembly of crimped sheets of polylactic acid defines a plurality of longitudinal channels that extend along the length of the aerosol cooling element 40.

[0123] Mouthpiece 50 is located directly downstream of and adjacent to aerosol cooling element 40. In the embodiment shown in Figure 1, mouthpiece 50 includes a conventional cellulose acetate tow filter with low filtration efficiency.

[0124] To assemble the aerosol-generating article 10, the four elements described above are aligned and intimately wrapped within a perforated outer wrapper 60. In the embodiment shown in Figure 1, a distal end portion of the outer wrapper 60 of the aerosol-generating article 10 is surrounded by a strip of non-perforated tipping paper 65.

[0125] When a user draws air through the mouthpiece of an aerosol-generating device without engaging the heated aerosol-generating article with the device, there is only a small resistance to drawing. As shown by the arrows in Figure 1, air enters the article 10 through the perforated outer wrapper 60. Because air can flow through the wrapper more easily than it can flow through the aerosol-forming substrate, substantially no air flows through the aerosol-forming substrate. Thus, if a user attempts to ignite the heated aerosol-generating article by applying a flame to the distal end 80 and drawing on the mouth end 70, there is insufficient airflow through the aerosol-forming substrate to easily suppress combustion, minimizing the risk of ignition.

[0126] Figure 2 illustrates a second embodiment of a heated aerosol-generating article. All elements are as described in Figure 1, with the exception that the support element 30 is a hollow tube, which defines a radially extending hole 37 between the inner surface of tube 31 and the outer surface of tube 32. The hole provides an additional airflow path allowing access between the inner portion of the aerosol-generating article and the perforated wrapper 60. Thus, the RTD of the article illustrated in Figure 2 may be even smaller than that illustrated in Figure 1.

[0127] The relative volumes of airflow through the aerosol-forming substrate and through the perforated wrapper depend on a number of parameters.

[0128] Darcy's law for flow through a porous body can be used to estimate the airflow through the aerosol-forming substrate. The airflow rate through the aerosol-forming substrate, Q p can be calculated as follows:

number

[0129] The air flow rate through one perforation in the wrapper can be approximated using the Hagen-Poiseuille equation for laminar fluid flow.

number

[0130] If there are n perforations, the total flow rate through all the perforations is:

number

[0131] Therefore, the distribution of airflow through the first airflow path and the second airflow path is as follows:

number

[0132] (ΔP) p (ΔP) v If it is assumed to be equal to

number

[0133] It can thus be seen that both the size and number of perforations, and the size and shape of the aerosol-forming substrate and wrapper are important. The permeability of the plug is also an important factor, and depends on the porosity of the aerosol-forming substrate and the thickness of the crimped tobacco sheet used.

[0134] By varying these parameters, a desired ratio of airflow through the wrapper to airflow through the plug can be obtained. For example, increasing the size or number of perforations in the wrapper will decrease the RTD through the wrapper. Increasing the length of the aerosol-forming substrate will increase the RTD through the aerosol-forming substrate.

[0135] The aerosol-generating article 10 depicted in Figure 1 or Figure 2 is designed to engage an aerosol-generating device that includes a heating element for smoking or consumption by a user. In use, the heating element of the aerosol-generating device heats the aerosol-forming substrate 20 of the aerosol-generating article 10 to a temperature sufficient to form an aerosol, which is drawn downstream through the aerosol-generating article 10 and inhaled by the user.

[0136] FIG. 3 illustrates a portion of an aerosol-generating system 100 including an aerosol-generating device 110 and an aerosol-generating article 10 according to the embodiment described above and illustrated in FIG.

[0137] The aerosol generating device includes a heating element 120. As shown in FIG. 3, the heating element 120 is mounted within the aerosol-generating article-receiving chamber of the aerosol generating device 110. In use, a user inserts the aerosol-generating article 10 into the aerosol-generating article-receiving chamber of the aerosol generating device 110 such that the heating element 120 is inserted directly into the aerosol-forming substrate 20 of the aerosol-generating article 10 shown in FIG. 3. In the embodiment shown in FIG. 3, the heating element 120 of the aerosol generating device 110 is a heater blade. The aerosol generating device 110 includes a power source and electronics capable of activating the heating element 120. Such activation may be manual or may occur automatically in response to a user's withdrawal of the aerosol-generating article 10 that is inserted into the aerosol-generating article-receiving chamber of the aerosol generating device 110.

[0138] When the heated aerosol-generating article 10 is properly engaged with the aerosol-generating device, the lip of the receiving chamber engages the outer surface of the article 10. The circumferential engagement between the article and the lip substantially impedes airflow into the receiving chamber, thereby substantially restricting airflow into the receiving chamber. A plurality of openings are provided in the aerosol-generating device to allow air to flow to the distal end of the aerosol-generating article 10. Thus, when a user draws on the mouth end of the article, the airflow path of least resistance is through the distal end of the article and through the aerosol-generating substrate, the direction of this airflow being shown by the arrows in FIG. 3.

[0139] The support element 30 of the aerosol-generating article 10 resists the penetration force experienced by the aerosol-generating article 10 during insertion of the heating element 120 of the aerosol-generating device 110 into the aerosol-forming substrate 20. The support element 30 of the aerosol-generating article 10 thereby resists downstream movement of the aerosol-forming substrate within the aerosol-generating article 10 during insertion of the heating element of the aerosol-generating device into the aerosol-forming substrate.

[0140] When the internal heating element 120 is inserted into the aerosol-forming substrate 10 of the aerosol-generating article 10 and activated, the aerosol-forming substrate 20 of the aerosol-generating article 10 is heated by the heating element 120 of the aerosol generating device 110 to a temperature of approximately 375 degrees Celsius. At this temperature, volatile compounds are released from the aerosol-forming substrate 20 of the aerosol-generating article 10. As a user inhales on the oral end 70 of the aerosol-generating article 10, the volatile compounds released from the aerosol-forming substrate 20 are drawn downstream through the aerosol-generating article 10 and condense to form an aerosol that is drawn through the mouthpiece 50 of the aerosol-generating article 10 into the user's mouth.

[0141] As the aerosol passes downstream through the aerosol cooling element 40, the temperature of the aerosol decreases due to the transfer of thermal energy from the aerosol to the aerosol cooling element 40. When the aerosol enters the aerosol cooling element 40, its temperature is approximately 60 degrees Celsius. Due to cooling within the aerosol cooling element 40, when the aerosol exits the aerosol cooling element, its temperature is approximately 40 degrees Celsius.

[0142] Although the support element of the aerosol-generating article according to the embodiment described above and illustrated in FIG. 1 is formed from cellulose acetate, it will be appreciated that this is not required and that aerosol-generating articles according to other embodiments may include a support element formed from any other suitable material or combination of materials.

[0143] Similarly, while the aerosol-generating article according to the embodiment described above and illustrated in FIG. 1 includes an aerosol cooling element comprising an assembly of crimped sheets of polylactic acid, it will be appreciated that this is not required and that aerosol-generating articles according to other embodiments may include other aerosol cooling elements.

[0144] Furthermore, while the aerosol-generating article according to the above embodiment and illustrated in FIG. 1 has four elements surrounded by an outer wrapper, it will be appreciated that this is not required and that aerosol-generating articles according to other embodiments may include additional or fewer elements.

[0145] It will be further appreciated that the dimensions provided for the elements of the aerosol generating article according to the above embodiment and illustrated in FIG. 1, and for the portions of the aerosol generating device according to the above embodiment and illustrated in FIG. 3, are merely exemplary, and suitable alternative dimensions may be selected.

[0146] In Figure 4, the components of the aerosol generation device 110 are shown in a simplified manner. In particular, the components of the aerosol generation device 110 are not drawn to scale in Figure 4. Components that are not relevant to an understanding of the embodiment have been omitted to simplify Figure 4.

[0147] As shown in Figure 4, the aerosol-generating device 110 includes a housing 6130. The heating element 6120 is mounted within an aerosol-generating article-receiving chamber within the housing 6130. The aerosol-generating article 10 (shown in dashed lines in Figure 4) is inserted into the aerosol-generating article-receiving chamber within the housing 6130 of the aerosol-generating device 110 such that the heating element 6120 is inserted directly into the aerosol-forming substrate 20 of the aerosol-generating article 10.

[0148] Within the housing 6130 is an electrical energy supply 6140, such as a rechargeable lithium ion battery. A controller 6150 is connected to the heating element 6120, the electrical energy supply 6140, and a user interface 6160, such as a button or a display. The controller 6150 controls the power supplied to the heating element 6120 to regulate its temperature.

[0149] The above exemplary embodiments are not limiting, and other embodiments consistent with the above exemplary embodiments will be apparent to those skilled in the art.

[0150] 1. A heated aerosol-generating article for use with an aerosol-generating device, the heated aerosol-generating article comprising a plurality of components including an aerosol-forming substrate assembled within a wrapper to form a rod having an oral end and a distal end upstream of the oral end, the heated aerosol-generating article defining a first airflow path in which air drawn into the aerosol-generating article through the oral end passes through the aerosol-forming substrate and a second airflow path in which air drawn into the aerosol-generating article through the oral end does not pass through the aerosol-forming substrate, and wherein a resistance to draw (RTD) of the second airflow path is less than the RTD of the first airflow path when the heated aerosol-generating article is not coupled to an aerosol-generating device. 2. The heated aerosol-generating article described in 1, wherein the RTD of the second airflow path is less than 10 mmWG when the heated aerosol-generating article is not coupled to an aerosol generating device. 3. The heated aerosol generating article according to 1 or 2, wherein the RTD of the second airflow path does not exceed 0.9 times the RTD of the first airflow path, and is preferably 0.2 to 0.7 times the RTD of the first airflow path, and more preferably 0.3 to 0.5 times the RTD of the first airflow path. 4. A heated aerosol-generating article as described in 1, 2 or 3, wherein interaction between the heated aerosol-generating article and an aerosol-generating device increases the RTD along the second airflow path as preferred along the first airflow path. 5. A heated aerosol-generating article described in any one of 1 to 4, wherein the aerosol-forming substrate is located at or towards the distal end of the rod, and one or more perforations through the wrapper downstream of the aerosol-forming substrate form part of the second airflow path. 6. A heated aerosol-generating article as described in any one of 1 to 5, wherein the wrapper is a highly perforable wrapper, allowing air to be drawn through the wrapper downstream of the aerosol-forming substrate into the heated aerosol-generating article. 7. A heated aerosol-generating article as described in any one of 1 to 6, wherein a support element is located downstream of the aerosol-forming substrate and a hole defined through a radial wall of the support element forms part of the second airflow path. 8. The heated aerosol-generating article according to any one of 1 to 7, wherein the aerosol-forming substrate comprises an aggregate of homogenized tobacco sheets. 9. A heated aerosol-generating article comprising a plurality of components including an aerosol-forming substrate assembled within a wrapper to form a rod having a mouth end and a distal end upstream of the mouth end, the heated aerosol-generating article defining a first airflow path in which air drawn into the aerosol-generating article through the mouth end passes through the aerosol-forming substrate and a second airflow path in which air drawn into the aerosol-generating article through the mouth end does not pass through the aerosol-forming substrate, the second airflow path having a lower resistance to draw (RTD) than the RTD of the first airflow path when the heated aerosol-generating article is not coupled to an aerosol generating device; A heated aerosol generating system comprising: an aerosol generating device having means for heating the aerosol-forming substrate, the aerosol generating device being arranged to engage the heated aerosol-generating article such that when a user inhales on the mouth end of the rod, the second airflow path is interrupted and air is drawn through the aerosol-forming substrate. 10. The heated aerosol generating system according to 8, wherein the heated aerosol generating article is an aerosol generating article according to any one of 1 to 8. 11. A heated aerosol generating system as described in either 9 or 10, wherein when the heated aerosol generating article is engaged with the aerosol generating device, the RTD of the second airflow path is greater than the RTD of the first airflow path. 12. The heated aerosol generating device according to any one of 9 to 11, wherein the means for heating the aerosol-forming substrate includes one or more heating elements insertable into the aerosol-forming substrate. 13. A heated aerosol generating device described in any one of 9 to 12, wherein the means for heating the aerosol-forming substrate includes one or more heating elements radially spaced from the aerosol-generating article when the aerosol-generating article is engaged with the aerosol generating device. 14. The heated aerosol generator according to any one of 9 to 13, wherein the means for heating the aerosol-forming substrate includes an inductor for heating a susceptor. 15. A method of smoking a heated aerosol-generating article comprising a plurality of components including an aerosol-forming substrate assembled within a wrapper to form a rod having a mouth end and a distal end upstream of the mouth end, the heated aerosol-generating article defining a first airflow path in which air drawn into the aerosol-generating article through the mouth end passes through the aerosol-forming substrate and a second airflow path in which air drawn into the aerosol-generating article through the mouth end does not pass through the aerosol-forming substrate, a resistance to draw (RTD) of the second airflow path being less than the RTD of the first airflow path when the heated aerosol-generating article is not coupled to an aerosol generating device, the method comprising: a) engaging the heated aerosol-generating article with an aerosol generating device such that the second airflow path is interrupted; b) operating the aerosol generating device to heat the aerosol-forming substrate; c) sucking on the mouth end of the rod to cause air to flow along the first airflow path, wherein an aerosol generated by heating the aerosol-forming substrate is entrained in the air as it passes through the aerosol-forming substrate. 16. The method according to claim 15, wherein the heated aerosol-generating article is an aerosol-generating article defined in any one of 1 to 9. 17. A heated aerosol-generating article for use with an aerosol generating device, the heated aerosol-generating article comprising a plurality of components including an aerosol-forming substrate assembled within a wrapper to form a rod having an oral end and a distal end upstream of the oral end, the heated aerosol-generating article defining a first airflow path through which air drawn into the aerosol-generating article through the oral end passes through the aerosol-forming substrate and a second airflow path through which air drawn into the aerosol-generating article through the oral end is drawn through the wrapper and into the rod, the second airflow path joining the first airflow path downstream of the aerosol-forming substrate, the second airflow path having a resistance to draw (RTD) through the wrapper that is less than the RTD of the first airflow path through the aerosol-forming substrate. 18. The heated aerosol generating article described in 17, wherein the RTD of the second airflow path is not more than 0.9 times the RTD of the first airflow path. 19. A heated aerosol-generating article for use with an aerosol generating device, the heated aerosol-generating article comprising a plurality of components including an aerosol-forming substrate assembled within a wrapper to form a rod having an oral end and a distal end upstream of the oral end, the heated aerosol-generating article defining a first airflow path through which air drawn into the aerosol-generating article through the oral end passes through the aerosol-forming substrate and a second airflow path through which air drawn into the aerosol-generating article through the oral end is drawn through the wrapper and into the rod, the second airflow path joining the first airflow path downstream of the aerosol-forming substrate, and the aerosol-generating article configured such that when suction is applied to the oral end of the rod and neither the first nor second airflow paths are obstructed, a greater volume of air is drawn through the second airflow path than is drawn through the first airflow path. 20. The heated aerosol-generating article of claim 19, wherein the volume of air drawn through the second airflow path is at least twice the volume of air drawn through the first airflow path.

Claims

1. 1. A heated aerosol-generating article comprising an aerosol-forming substrate for generating an inhalable aerosol when heated using an aerosol generating device, the heated aerosol-generating article comprising a plurality of components including the aerosol-forming substrate assembled within a wrapper to form a rod having a mouth end and a distal end upstream of the mouth end, the heated aerosol-generating article defining a first airflow path in which air drawn into the aerosol-generating article through the mouth end passes through the aerosol-forming substrate and a second airflow path in which air drawn into the aerosol-generating article through the mouth end does not pass through the aerosol-forming substrate, the second airflow path having a lower draw resistance than the first airflow path, the plurality of components further comprises a hollow tubular element and a mouthpiece, the hollow tubular element being located upstream of the mouthpiece and immediately downstream of the aerosol-forming substrate; Heated aerosol generating products.

2. 2. The heated aerosol generating article according to claim 1, wherein the resistance to airflow of the second airflow path is not more than 0.9 times the resistance to airflow of the first airflow path.

3. 3. The heated aerosol-generating article according to claim 2, wherein the resistance to airflow of the second airflow path is between 0.3 and 0.5 times the resistance to airflow of the first airflow path.

4. 4. The heated aerosol-generating article according to claim 1, wherein a hole is defined through a radial wall of the hollow tubular element that forms part of the second airflow path.

5. The heated aerosol-generating article according to any one of claims 1 to 3, wherein the wrapper is a highly perforated wrapper, allowing air to be drawn through the wrapper downstream of the aerosol-forming substrate into the heated aerosol-generating article, and holes are defined through the radial wall of the hollow tubular element that form part of the second airflow path.

6. The heated aerosol-generating article according to any one of claims 1 to 5, wherein the hollow tubular element is made of cardboard.

7. The heated aerosol-generating article according to any one of claims 1 to 6, wherein the hollow tubular element has a length of at least 5 millimeters.

8. The heated aerosol-generating article according to any one of claims 1 to 7, wherein the mouthpiece comprises a filter formed from cellulose acetate tow.

9. The heated aerosol generating article according to any one of claims 1 to 8, wherein the mouthpiece has a length between 5 millimeters and 20 millimeters.

10. The heated aerosol-generating article of any one of claims 1 to 9, wherein the aerosol-forming substrate comprises between 5% and approximately 30% of an aerosol-forming agent selected from any one of propylene glycol, triethylene glycol, 1,3-butanediol, glycerin, glycerol monoacetate, glycerol diacetate, glycerol triacetate acetate, dimethyl dodecanedioate, and dimethyl tetradecanedioate, based on the dry weight of the aerosol-forming agent.

11. The heated aerosol-generating article of any one of claims 1 to 10, wherein the aerosol-forming substrate is located at or towards the distal end of the rod, and one or more perforations through the wrapper downstream of the aerosol-forming substrate define part of the second airflow path.

12. 12. The heated aerosol-generating article of claim 1, wherein the wrapper is a highly perforated wrapper, allowing air to be drawn into the heated aerosol-generating article through the wrapper downstream of the aerosol-forming substrate.

13. The heated aerosol-generating article is an aerosol-generating article according to any one of claims 1 to 12, and an aerosol generating device comprising means for heating said aerosol-forming substrate; A heated aerosol generating system comprising:

14. 14. The heated aerosol generating system of claim 13, wherein the means for heating the aerosol-forming substrate comprises an inductor for heating a susceptor.

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