Aerosol-generating article with low resistance air flow 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. The heated aerosol-generating article defines a first air-flow path in which air drawn into the aerosol-generating article through the mouth end passes through the aerosol-forming substrate, and a second air-flow path in which air drawn into the aerosol-generating article through the mouth end does not pass through the aerosol-forming substrate. 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 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 aerosol that can be inhaled 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 methods of using such aerosol-generating articles.

Background Art

[0002] Aerosol-generating articles in which an aerosol-forming substrate, such as a tobacco-containing substrate, is heated rather than burned are well known in the art. One aim 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] Conventional cigarettes are ignited when a user applies a flame to one end of the cigarette and draws air through the other end. The local heat provided by the flame and the oxygen in the air drawn through the cigarette ignites the end of the cigarette, and the resulting combustion generates inhalable smoke. In contrast, in heated aerosol-generating articles, inhalable aerosol is typically generated by heat transfer from a heat source to an aerosol-forming substrate or material physically separated from the heat source, which may be located within, 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 carried together in the air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol, which is inhaled by the consumer.

[0004] Heated aerosol generating articles containing 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 a heated aerosol generating article and an aerosol generating device having a heater for heating the heated aerosol generating article to generate an aerosol.

[0005] Tobacco used as part of an aerosol forming substrate in a heated aerosol generating article is designed to generate an aerosol when heated rather than when burned. Thus, such tobacco generally contains high levels of aerosol forming agents such as glycerin or propylene glycol. If a user lights a heated aerosol generating article and smokes it as if it were a conventional cigarette, that user will not have the intended user experience. It would be desirable to manufacture heated aerosol generating articles with a low or no tendency to ignite by a flame. Such heated aerosol generating articles preferably have difficulty igniting when the article is attempted to be ignited in the traditional cigarette manner with a lighter (such as a flame).

Summary of the Invention

[0006] A heated aerosol generating article may be provided for use in combination with an aerosol generating device. The heated aerosol generating article may comprise 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 defines a first potential airflow path through which air drawn into the aerosol generating article through the mouth end passes through the aerosol forming substrate, and a second potential airflow path through which air drawn into the aerosol generating article through the mouth end does not pass through the aerosol forming substrate. When the heated aerosol generating article is not coupled to the aerosol generating device, the draw resistance (RTD) of the second airflow path is less than the RTD of the first airflow path. The second airflow path has a lower resistance compared to the first airflow path.

[0007] When the heated aerosol generating article is not coupled to the aerosol generating device, the preferred airflow path for the air drawn through the heated aerosol generating article through the mouth-side end is the second airflow path. Thus, when a user inhales at the mouth-side end of the heated aerosol generating article without engaging the heated aerosol generating article with the 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 inhaling from the mouth-side 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 draw resistance (RTD) when not connected to the aerosol generating device. For example, the effective RTD may be close to zero. This may prevent the user from drawing enough air through the aerosol-forming substrate to ignite it. The second airflow path may be any airflow path that prevents sufficient airflow through the aerosol-forming substrate to prevent self-sustained combustion of the substrate when an attempt is made to ignite the article.

[0009] It is preferred to increase the RTD along the second airflow path so that the interaction between the heated aerosol generating article and the aerosol generating device prioritizes the airflow along the first airflow path. 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 has a higher resistance than the first airflow path. Thus, the 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 can be located at or towards the distal end of the rod. One or more holes or perforations defined through a wrapper downstream of the aerosol-forming substrate can define a portion of the second airflow path. Thus, when the heated aerosol-generating article is not engaged with the aerosol-generating device, the airflow path with the lowest resistance is the one that enters the article through the holes or perforations in the wrapper downstream of the aerosol-forming substrate. Next, the air flowing into the article through this path is drawn out through the mouth-side 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 can draw air through the wrapper downstream of the aerosol-forming substrate into the heated aerosol-generating article. The perforated wrapper can reduce the RTD of the heated aerosol-generating article to almost zero.

[0012] A support element such as a hollow acetate tube can be located downstream of the aerosol-forming substrate. Radially extending holes can 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 almost zero. The wrapper may define holes that overlap with 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 an assembly of at least one sheet of material. The assembly of sheets of material can be a sheet of homogenized tobacco. The aerosol-forming substrate can also be a rod of a tobacco assembly as described in WO 2012 / 164009.

[0014] A heated aerosol generation system may comprise a heated aerosol generating article according to any one of the above embodiments and an aerosol generating device including means for heating an aerosol forming substrate. The aerosol generating device is arranged to engage with the heated aerosol generating article such that when the user sucks at the mouth-side end of the rod, the second air flow path is interrupted and air is drawn through the aerosol forming substrate.

[0015] Engagement of the heated aerosol generating device with the aerosol generating article preferably increases the resistance along the second air flow path. Thus, the preferred air flow path is the first air flow 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 enough to increase or completely prevent the flow of air along the second air flow path. By the device, air can 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 air flow holes or perforations defined within 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 a heating element, such as a heating element insertable into the aerosol generating article or a heating element arranged adjacent to the aerosol generating article. The heating means may comprise an inductor for interacting with a susceptor, such as an induction coil.

[0018] The method of smoking or consuming an aerosol-generating article described herein may include engaging a heated aerosol-generating article with an aerosol-generating device such that a second airflow path is interrupted, operating the aerosol-generating device to heat an aerosol-forming substrate, and inhaling at the mouth-side end of the rod to cause flow along a first airflow path. When passing through the aerosol-forming substrate, the aerosol generated by heating the aerosol-forming substrate is mixed with air.

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

[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 inhales during their use of the aerosol-generating article.

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

[0022] Also, the proximal end may be referred to as the mouth-side end or the downstream end and is downstream of the distal end. Also, the distal end may 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 having a large surface area and a low draw resistance. In use, an aerosol formed by a volatile compound released from an 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 an aerosol-generating article are not considered to be aerosol cooling elements.

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

[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 can be directly inhaled into the user's lungs through the user's mouth. The aerosol-generating device preferably interacts with the aerosol-generating article to cause air to flow through the aerosol-forming substrate.

[0026] To avoid misunderstanding, 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 dimension in the lateral direction of an aerosol-generating article. As used herein, the term "length" is used to describe the maximum dimension in the longitudinal axis direction of an 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 contains nicotine. More preferably, the aerosol-forming substrate contains tobacco.

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

[0032] When the aerosol-forming substrate is a solid aerosol-forming substrate, the solid aerosol-forming substrate may comprise one or more of herb leaves, tobacco leaves, tobacco stems, expanded tobacco and homogenized tobacco, for example, one or more of powder, granule, pellet, fragment, thread, flake or sheet.

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

[0034] Optionally, the solid aerosol-forming substrate may be provided on or embedded within a thermally stable carrier. The carrier may take the form of a powder, granule, pellet, fragment, yarn, chip or sheet. The solid aerosol-forming substrate may, for example, be deposited on the surface of the carrier in the form of a sheet, foam, gel or slurry. The solid aerosol-forming substrate may be deposited over the entire surface of the carrier or, alternatively, may be deposited in a pattern to provide non-uniform flavor delivery during use.

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

[0036] As used herein, the term "homogenized tobacco material" means a material formed by aggregating particulate tobacco.

[0037] Preferably, the aerosol-forming substrate comprises an assembly of sheets of homogenized tobacco material.

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

[0039] As used herein, the term "assembled" is used to describe a sheet that has been rolled, folded, or otherwise substantially compressed or shrunk transversely with respect to the longitudinal axis of the aerosol-generating article.

[0040] The use of an aerosol-forming substrate comprising an assembly of sheets of homogenized tobacco material advantageously significantly reduces the risk of "end looseness" compared to an aerosol-forming substrate comprising fragments of tobacco material (i.e., there is a loss of fragments of tobacco material from the end of the rod). End looseness can disadvantageously lead to a greater need for frequent cleaning of aerosol-generating devices and manufacturing equipment for use in combination with aerosol-generating articles.

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

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

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

[0044] The use of textured sheets of homogenized tobacco material may conveniently facilitate the aggregation of sheets of homogenized tobacco material to form the aerosol-forming substrate.

[0045] As used herein, the term "crimped sheet" means a sheet having a plurality of substantially parallel ridges or wrinkles. When the aerosol-generating article is assembled, the substantially parallel ridges or wrinkles preferably extend along or parallel to the longitudinal axis of the aerosol-generating article. This conveniently facilitates the assembly of an assembly of crimped sheets of homogenized tobacco material to form the aerosol-forming substrate. However, it is recognized that the crimped sheets of homogenized tobacco material for inclusion in the 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 assembly of sheets of homogenized tobacco material that are substantially uniform and textured substantially over its entire surface. For example, the aerosol-forming substrate may comprise an assembly of crimped sheets of homogenized tobacco material that includes a plurality of substantially parallel ridges or wrinkles 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 an aerosol-forming material surrounded by 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 assembly of discrete sheets of homogenized tobacco material surrounded by a wrapper. In a particularly preferred embodiment, the aerosol-generating substrate comprises a plug comprising an assembly of crimped sheets of homogenized tobacco material surrounded by a wrapper.

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

[0050] The sheets of homogenized tobacco material for use in the aerosol-generating substrate are one or more intrinsic binders which are tobacco endogenous binders, one or more extrinsic binders which are tobacco exogenous binders, or a combination thereof, to assist in aggregating particulate tobacco. As another alternative or in addition, the sheets of homogenized tobacco material for use in the 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 exogenous binders for inclusions in a sheet of homogenized tobacco material for use in an aerosol-generating substrate are well known in the art and include gums such as guar gum, xanthan gum, gum arabic and locust bean gum; cellulose binders such as hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose and ethyl cellulose; polysaccharides such as starches, organic acids such as alginic acid, conjugate base salts of organic acids such as sodium alginate, agar and pectin; and combinations thereof, but are not limited thereto.

[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 cellulose fibers; softwood fibers; hardwood fibers; jute fibers and combinations thereof, but are not limited thereto. Prior to inclusion in a sheet of homogenized tobacco material for use in an aerosol-generating substrate, the non-tobacco fibers may be processed by suitable processes well known in the art, including mechanical pulping; refining; chemical pulping; bleaching; sulfate pulping; and combinations thereof, but are not limited thereto.

[0053] A sheet of homogenized tobacco material for use in an aerosol-generating substrate must have a sufficiently high tensile strength to withstand the assembly for forming the aerosol-generating substrate. In certain embodiments, non-tobacco fibers may be included in the sheet of homogenized tobacco material for use in an aerosol-generating substrate to achieve an appropriate tensile strength.

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

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

[0056] As used herein, the term "aerosol forming agent" is used in the context of describing any suitable well-known compound or mixture of compounds that 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. 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 more than 5% on a dry mass basis.

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

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

[0063] An aerosol-forming substrate comprising an assembly of homogenized tobacco sheets for use in an aerosol-generating article can be manufactured by methods well known in the art, for example, as disclosed in WO 2012 / 164009 A2.

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

[0065] The aerosol-forming element preferably has an outer diameter substantially 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 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 approximately 7 millimeters and approximately 15 mm. In one embodiment, the aerosol-forming substrate may have a length of approximately 10 millimeters. In a preferred embodiment, the aerosol-forming substrate has a length of approximately 12 millimeters.

[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; crinkled paper such as crinkled heat-resistant paper or crinkled sulfuric acid 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 include a hollow tubular element. In a preferred embodiment, the support element includes a hollow cellulose acetate tube.

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

[0073] The support element may have an outer diameter 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 support element has an outer diameter of 7.2 millimeters + / - 10%.

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

[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 the mouthpiece located at the extreme downstream end of the aerosol generating article.

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

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

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

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

[0081] The aerosol cooling element may include a plurality of paths extending in the long axis direction. The plurality of paths extending in the long axis direction may be defined by a sheet material in which one or more of crimping, pleating, gathering, and folding are performed to form the paths. The plurality of paths extending in the long axis direction may be defined by a single sheet in which one or more of crimping, pleating, gathering, and folding are performed to form the plurality of paths. Alternatively, the plurality of paths extending in the long axis direction may be defined by a plurality of sheets in which one or more of crimping, pleating, gathering, and folding are performed to form the plurality of paths.

[0082] In some embodiments, the aerosol cooling element may include an assembly of material sheets selected from the group consisting of metal foils, polymeric materials, and substantially non-porous paper or cardboard. In some embodiments, the aerosol cooling element may include an assembly of sheets of materials 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 between approximately 5 millimeters and approximately 10 millimeters, for example between approximately 6 millimeters and approximately 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 approximately 5 millimeters and approximately 25 mm. In a preferred embodiment, the aerosol cooling element has a length of approximately 18 millimeters.

[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 materials, 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 a grade of Mater-Bi® (a commercial 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 the downstream end of the aerosol generating article.

[0089] The mouthpiece may be located directly downstream of 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 well 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 that is approximately equal to the outer diameter of the aerosol generating article.

[0092] The mouthpiece may have an outer diameter between approximately 5 millimeters and approximately 10 millimeters, for example between approximately 6 millimeters and approximately 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 approximately 5 millimeters and approximately 20 millimeters. In a preferred embodiment, the mouthpiece has a length of approximately 14 millimeters.

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

[0095] The aerosol forming substrate, and any other components of the heated aerosol generating article, are assembled within a wrapper that surrounds it. The wrapper 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 lit-end cigarette.

[0098] The aerosol-generating article may have an outer diameter between approximately 5 millimeters and approximately 12 millimeters, for example between approximately 6 millimeters and approximately 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 between approximately 30 millimeters and approximately 100 millimeters. In a preferred embodiment, the aerosol-generating article has an overall length of approximately 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 recess surrounding the heating element, the recess being configured to receive the heated aerosol-generating article and interact with the aerosol-generating article to interrupt or close a second airflow path such that air is drawn through the aerosol-forming substrate.

[0102] The aerosol-generating device is preferably a portable or hand-held aerosol-generating device that is easy for a user to hold 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 approximately 70 millimeters and approximately 120 millimeters.

[0105] The power supply may be any suitable power supply, such as a DC 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, such as a lithium cobalt, lithium iron phosphate, lithium titanate or lithium polymer battery.

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

[0107] The heating element of the aerosol generator may be any suitable heating element that can be inserted into the aerosol-forming substrate of the aerosol 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 article.

[0109] The draw resistance (RTD) of the aerosol article before engagement with the aerosol generator is preferably close to zero (e.g., less than 10 mmWG). The RTD after engagement with the aerosol generator can be approximately 80 mmWG to approximately 140 mmWG, preferably 110 - 115 mmWG.

[0110] As used herein, draw 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 in combination with an aerosol generating device. The heated aerosol generating article comprises 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 defines a first airflow path through which air drawn into the aerosol generating article through the mouth-end passes through the aerosol-forming substrate, and a second airflow path through which air drawn into the aerosol generating article through the mouth-end is drawn through the wrapper to the rod. Here, the second airflow path merges with the first airflow path at a position downstream of the aerosol-forming substrate, and the draw resistance (RTD) of the second airflow path through the wrapper is smaller than the RTD of the first airflow path through the aerosol-forming substrate.

[0112] Preferably, the RTD of the second airflow path does not exceed 0.9 times the RTD of the first airflow path, more preferably is 0.2 to 0.7 times the RTD of the first airflow path, and even more preferably is 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 in combination with an aerosol generating device. The heated aerosol generating article comprises 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 defines a first airflow path through which air drawn into the aerosol generating article through the mouth-end passes through the aerosol-forming substrate, and a second airflow path through which air drawn into the aerosol generating article through the mouth-end is drawn through the wrapper to the rod. Here, the second airflow path merges with the first airflow path at a position downstream of the aerosol-forming substrate, and when suction is applied to the mouth-end of the rod, the aerosol generating article is configured such that neither the first nor the second airflow path is blocked, and a larger volume of air is drawn through the second airflow path than through the first airflow path.

[0114] The volume of air drawn through the second air flow path is preferably at least twice the volume of air drawn through the first air flow path.

[0115] Also, features described with respect to one aspect or embodiment may be applicable to other aspects and embodiments. For example, the features described with respect to the aerosol generating article and aerosol generating system above may also be used in combination with the method of using the aerosol generating article and aerosol generating system above.

[0116] Specific embodiments will now be described with reference to the figures.

Brief Description of the Drawings

[0117]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0118] Figure 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 succession and are surrounded by an outer wrapper 60 to form the heated aerosol generating article 10. The aerosol generating article 10 has a proximal or mouth-side end 70 which the user inserts into the user's mouth during use, and a distal end 80 which is located at the end of the aerosol generating article 10 opposite the mouth-side end 70. The outer wrapper 60 is a highly perforated paper with little or no resistance to airflow through the paper. A non-perforated tipping paper 65 surrounds the mouthpiece end of the article 10.

[0119] Also, the distal end 80 of the aerosol generating article may be described as the upstream end of the aerosol generating article 10, and the mouth-side end 70 of the aerosol generating article 10 may also be described as the downstream end of the aerosol generating article 10. The elements of the aerosol generating article 10 located between the mouth-side end 70 and the distal end 80 can be described as being upstream of the mouth-side 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 includes an assembly of sheets of crimped and homogenized tobacco material surrounded by a wrapper. The crimped sheets of homogenized tobacco material contain glycerin as an aerosol forming agent.

[0121] The support element 30 is located directly downstream of the aerosol forming substrate 20 and is 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 distal end 80 of the outermost end of the aerosol generating article 10 such that it can be penetrated by the heating element of the aerosol generating device. Further, the support element 30 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 cooling element 40 of the aerosol generating article 10.

[0122] The aerosol cooling element 40 is located directly downstream of the support element 30 and is adjacent to the support element 30. In use, the volatile substances released from the aerosol forming substrate 20 pass along the aerosol cooling element 40 towards the mouth-side end 70 of the aerosol generating article 10. The volatile substances may cool within the aerosol cooling element 40 to form an aerosol that is inhaled by the user. In the embodiment illustrated in FIG. 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 longitudinally extending paths along the length of the aerosol cooling element 40.

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

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

[0125] When the user draws air through the mouthpiece of the device without engaging the heated aerosol generating article with the aerosol generator, the draw resistance is minimal. As indicated by the arrow in FIG. 1, air enters the article 10 through the perforated outer wrapper 60. Since the air can flow through the wrapper more easily than through the aerosol forming substrate, substantially no air flows through the aerosol forming substrate. Thus, when the user attempts to ignite the heated aerosol generating article by applying a flame to the distal end 80 and sucking on the mouth-side end 70, the airflow through the aerosol forming substrate is insufficient and combustion is easily suppressed, minimizing the risk of ignition.

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

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

[0128] Using Darcy's law for flow through a porous body, the airflow through the aerosol forming substrate can be estimated. The air flow rate Q p through the aerosol forming substrate can be calculated as follows.

Equation

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

Number

[0130] When there are n perforations, the total flow rate through all the perforations is as follows.

Number

[0131] Therefore, the distribution of the air flow through the first air flow path and the air flow through the second air flow path is as follows.

Number

[0132] (ΔP) p is assumed to be equal to (ΔP) v In that case, it can be simplified as follows.

Number

[0133] Therefore, it can be understood that both the size and number of the perforations, and the size and shape of the aerosol-forming substrate and the 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 the airflow through the wrapper to the airflow through the plug can be obtained. For example, increasing the size or number of the perforations in the wrapper results in a decrease in the RTD through the wrapper. Increasing the length of the aerosol-forming substrate results in an increase in the RTD through the aerosol-forming substrate.

[0135] The aerosol-generating article 10 illustrated in FIG. 1 or FIG. 2 is designed to engage with an aerosol-generating device including a heating element for being smoked or consumed 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. 1.

[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, the 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 directly inserted into the aerosol forming substrate 20 of the aerosol generating article 10 as 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 operating the heating element 120. Such operation may be manual or may occur automatically in response to the user withdrawing the aerosol generating article 10 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 prevents airflow into the receiving chamber and thus substantially restricts 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 the user inhales at the mouth-side end of the article, the path of least resistance for the airflow is through the distal end of the article and through the aerosol generating substrate, and the direction of this airflow is indicated by the arrow 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. Thereby, the support element 30 of the aerosol generating article 10 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] The internal heating element 120 is inserted into the aerosol-forming substrate 10 of the aerosol-generating article 10 and, when activated, the aerosol-forming substrate 20 of the aerosol-generating article 10 is heated to a temperature of approximately 375 degrees Celsius by the heating element 120 of the aerosol-generating device 110. At this temperature, the volatile compounds are released from the aerosol-forming substrate 20 of the aerosol-generating article 10. As the user inhales at the mouth-side 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, condense and form an aerosol that is drawn into the user's mouth through the mouthpiece 50 of the aerosol-generating article 10.

[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 the cooling within the aerosol cooling element 40, its temperature when the aerosol exits the aerosol cooling element is approximately 40 degrees Celsius.

[0142] The support element of the aerosol-generating article according to the above and the embodiment illustrated in FIG. 1 is formed from cellulose acetate, but this is not essential, and it will be recognized that aerosol-generating articles according to other embodiments may include support elements formed from other suitable materials or combinations of materials.

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

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

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

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

[0147] As shown in FIG. 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 FIG. 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 there is an electrical energy supply 6140, such as a rechargeable lithium ion battery. The controller 6150 is connected to the heating element 6120, the electrical energy supply 6140 and a user interface 6160, such as a button or 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. 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 in combination with an aerosol generating device, the heated aerosol generating article comprising a plurality of components including an aerosol-forming substrate assembled inside a wrapper to form a rod having a mouth-side end and a distal end upstream of the mouth-side end, the heated aerosol generating article defining a first airflow path through which air drawn into the aerosol generating article through the mouth-side end passes through the aerosol-forming substrate, and a second airflow path through which air drawn into the aerosol generating article through the mouth-side end does not pass through the aerosol-forming substrate, and when the heated aerosol generating article is not coupled to the aerosol generating device, the draw resistance (RTD) of the second airflow path is less than the RTD of the first airflow path. 2. The heated aerosol generating article according to 1, wherein when the heated aerosol generating article is not coupled to the aerosol generating device, the RTD of the second airflow path is less than 10 mmWG. 3. Preferably, the RTD of the second airflow path does not exceed 0.9 times the RTD of the first airflow path and is 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. The heated aerosol generating article according to 1 or 2. 4. The heated aerosol generating article according to 1, 2 or 3, wherein the interaction between the heated aerosol generating article and the aerosol generating device preferentially along the first airflow path increases the RTD along the second airflow path. 5. The heated aerosol generating article according to any one of 1 to 4, wherein the aerosol-forming substrate is located at or directed towards the distal end of the rod, and one or more perforations passing through the wrapper downstream of the aerosol-forming substrate form part of the second airflow path. 6. The heated aerosol generating article according to any one of 1 to 5, wherein the wrapper is a wrapper with high puncture resistance, and air is allowed to be drawn into the heated aerosol generating article through the wrapper downstream of the aerosol forming substrate. 7. The heated aerosol generating article according to any one of 1 to 6, wherein the support element is located downstream of the aerosol forming substrate, and a hole defined through the radial wall of the support element forms part of the second air flow path. 8. The heated aerosol generating article according to any one of 1 to 7, wherein the aerosol forming substrate includes an assembly of homogenized tobacco sheets. 9. A heated aerosol generating article comprising a plurality of components including an aerosol forming substrate assembled inside a wrapper to form a rod having a mouth-side end and a distal end upstream of the mouth-side end, the heated aerosol generating article defining a first air flow path through which air drawn into the aerosol generating article through the mouth-side end passes through the aerosol forming substrate, and a second air flow path through which air drawn into the aerosol generating article through the mouth-side end does not pass through the aerosol forming substrate, and when the heated aerosol generating article is not coupled to an aerosol generating device, the draw resistance (RTD) of the second air flow path is smaller than the RTD of the first air flow path. An aerosol generating device comprising means for heating the aerosol forming substrate, the aerosol generating device being arranged to engage with the heated aerosol generating article such that when the user sucks at the mouth-side end of the rod, the second air flow 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 the aerosol generating article according to any one of 1 to 8. 11. The heated aerosol generating system according to either 9 or 10, wherein when the heated aerosol generating article is engaged with the aerosol generating device, the RTD of the second air flow path is greater than the RTD of the first air flow path. 12. The heating 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 that can be inserted into the aerosol forming substrate. 13. The heating aerosol generating device according to any one of 9 to 12, wherein the means for heating the aerosol forming substrate includes one or more heating elements that are radially spaced from the aerosol generating article when the aerosol generating article is engaged with the aerosol generating device. 14. The heating aerosol generating device 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 inside a wrapper to form a rod having a mouth-side end and a distal end upstream of the mouth-side end, wherein the heated aerosol generating article defines a first airflow path through which air drawn into the aerosol generating article through the mouth-side end passes through the aerosol forming substrate and a second airflow path through which air drawn into the aerosol generating article through the mouth-side end does not pass through the aerosol forming substrate, and when the heated aerosol generating article is not coupled to the aerosol generating device, a draw resistance (RTD) of the second airflow path is less than an RTD of the first airflow path, the method comprising: a) engaging the heated aerosol generating article with the 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 at the mouth-side end of the rod to allow air to flow along the first airflow path, wherein aerosol generated by heating of the aerosol forming substrate is mixed into the air as the aerosol passes through the aerosol forming substrate. 16. The method according to 15, wherein the heated aerosol generating article is an aerosol generating article as defined by any one of 1 to 9. 17. A heated aerosol-generating article for use in combination 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 a mouth-side end and a distal end upstream of the mouth-side end, the heated aerosol-generating article defining a first airflow path through which air drawn into the aerosol-generating article through the mouth-side end passes through the aerosol-forming substrate, and a second airflow path through which air drawn into the aerosol-generating article through the mouth-side end is drawn through the wrapper to the rod, the second airflow path merging with the first airflow path at a position downstream of the aerosol-forming substrate, and the draw resistance (RTD) of the second airflow path through the wrapper being less than the RTD of the first airflow path through the aerosol-forming substrate. 18. The heated aerosol-generating article according to claim 17, wherein the RTD of the second airflow path does not exceed 0.9 times the RTD of the first airflow path. 19. A heated aerosol-generating article for use in combination 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 a mouth-side end and a distal end upstream of the mouth-side end, the heated aerosol-generating article defining a first airflow path through which air drawn into the aerosol-generating article through the mouth-side end passes through the aerosol-forming substrate, and a second airflow path through which air drawn into the aerosol-generating article through the mouth-side end is drawn through the wrapper to the rod, the second airflow path merging with the first airflow path at a position downstream of the aerosol-forming substrate, and the aerosol-generating article being configured such that, when suction is applied to the mouth-side end of the rod and neither the first nor the second airflow path is blocked, a greater volume of air is drawn through the second airflow path than through the first airflow path. 20. The heated aerosol generating article according to 19, wherein the volume of the air drawn through the second air flow path is at least twice the volume of the air drawn through the first air flow path.

Claims

**Claim 1** A heated aerosol generating article comprising an aerosol-forming substrate for generating an inhalable aerosol when heated using an aerosol generator, the heated aerosol generating article being assembled inside a wrapper and comprising a plurality of components including the aerosol-forming substrate that forms a rod having a mouth-side end and a distal end upstream of the mouth-side end, the heated aerosol generating article defining a first airflow path through which air drawn into the aerosol generating article through the mouth-side end passes through the aerosol-forming substrate, and a second airflow path through which air drawn into the aerosol generating article through the mouth-side end does not pass through the aerosol-forming substrate, the draw resistance of the second airflow path being lower than the draw resistance of the first airflow path, wherein the aerosol-forming substrate contains an aerosol-forming agent, and the content of the aerosol-forming agent in the aerosol-forming substrate is between 5% and 30% on a dry mass basis. A heated aerosol generating article. **Claim 2** The heated aerosol generating article according to claim 1, wherein the draw resistance of the second airflow path does not exceed 0.9 times the draw resistance of the first airflow path. **Claim 3** The heated aerosol generating article according to claim 2, wherein the draw resistance of the second airflow path is between 0.3 and 0.5 times the draw resistance of the first airflow path. **Claim 4** The heated aerosol generating article according to any one of claims 1 to 3, wherein the plurality of components further comprises a hollow tubular element and a mouthpiece, and the hollow tubular element is located upstream of the mouthpiece and immediately downstream of the aerosol-forming substrate. **Claim 5** The heated aerosol generating article according to claim 4, wherein holes are defined through a radially directed wall of the hollow tubular element to form part of the second airflow path. **Claim 6** The heated aerosol generating article according to claim 4, wherein the wrapper is a highly perforated wrapper that permits air to be drawn into the heated aerosol generating article through the wrapper downstream of the aerosol-forming substrate, and holes are defined through a radially directed wall of the hollow tubular element to form part of the second airflow path. **Claim 7** The heated aerosol generating article according to any one of claims 4 to 6, wherein the hollow tubular element is made of cardboard. **Claim 8** The heated aerosol generating article according to any one of claims 4 to 7, wherein the hollow tubular element has a length of at least 5 millimeters.

9. The heated aerosol generating article according to any one of claims 4 to 8, wherein the mouthpiece comprises a filter formed from cellulose acetate tow.

10. The heated aerosol generating article according to any one of claims 4 to 9, wherein the mouthpiece has a length between 5 millimeters and 20 millimeters.

11. The heated aerosol generating article according to any one of claims 1 to 10, wherein the aerosol-forming substrate comprises 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, in an amount between 5% and approximately 30% based on the dry mass of the aerosol-forming agent.

12. The heated aerosol generating article according to any one of claims 1 to 11, 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 a part of the second airflow path.

13. The heated aerosol generating article according to any one of claims 1 to 12, wherein the wrapper is a highly perforated wrapper that allows air to be drawn into the heated aerosol generating article through the wrapper downstream of the aerosol-forming substrate.

14. The heated aerosol generating article as described in any one of claims 1 to 13, and An aerosol generating device comprising means for heating the aerosol-forming substrate, A heated aerosol generating system comprising.

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

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