Aerosol generating article having a thick wrapper

Abstract

The present invention relates to an aerosol-generating article. The aerosol-generating article comprises an aerosol-forming substrate within an aerosol-forming substrate portion. The aerosol-generating article comprises a substrate wrapper that at least partially surrounds the aerosol-forming substrate portion. The substrate wrapper has a thickness of 50 micrometers or more. The substrate wrapper does not extend beyond the end of the aerosol-forming substrate portion in the longitudinal axis direction of the aerosol-generating article. The aerosol-forming substrate comprises an aerosol-forming agent content of at least 35 weight percent. The present invention further relates to an aerosol-generating system.

Description

Technical Field

[0001] The present disclosure relates to aerosol-generating articles. The present disclosure further relates to aerosol generation systems.

Background Art

[0002] It is known to provide an aerosol-generating device for generating inhalable vapor. Such a device may heat an aerosol-forming substrate contained in an aerosol-generating article without burning the aerosol-forming substrate. The aerosol-generating article may have a rod shape for insertion into the heating chamber of the aerosol-generating device.

[0003] The aerosol-generating device may comprise a heating arrangement. The heating arrangement may be an induction heating arrangement and may comprise an induction coil configured to be inductively heated by a susceptor. The susceptor may be part of the device or part of the aerosol-generating article.

[0004] It is desirable to provide a more efficient aerosol-generating article. It may be desirable to provide an aerosol-generating article that requires a smaller amount of aerosol-forming substrate. It would be desirable to provide a more mechanically robust aerosol-generating article. It would be desirable to provide an aerosol-generating article that helps prevent leakage of the aerosol-forming substrate. It would be desirable to provide an aerosol-generating article that can be used with existing aerosol-generating devices.

Summary of the Invention

[0005] According to an embodiment of the present invention, an aerosol generating article is provided. The aerosol generating article may comprise an aerosol forming substrate within an aerosol forming substrate portion. The aerosol generating article may comprise a substrate wrapper that at least partially surrounds the aerosol forming substrate portion. The substrate wrapper may have a thickness of 50 micrometers or more. The substrate wrapper may not extend beyond the end of the aerosol forming substrate portion in the long axis direction of the aerosol generating article. The aerosol forming substrate may comprise an aerosol former content of at least 35 weight percent.

[0006] According to an embodiment of the present invention, an aerosol generating article is provided. The aerosol generating article comprises an aerosol forming substrate within an aerosol forming substrate portion. The aerosol generating article comprises a substrate wrapper that at least partially surrounds the aerosol forming substrate portion. The substrate wrapper has a thickness of 50 micrometers or more. The substrate wrapper does not extend beyond the end of the aerosol forming substrate portion in the long axis direction of the aerosol generating article. The aerosol forming substrate comprises an aerosol former content of at least 35 weight percent.

[0007] A combination of a thick substrate wrapper having a thickness of 50 micrometers or more and an aerosol forming substrate comprising an aerosol former content of at least 35 weight percent can provide an efficient aerosol generating article without changing the outer diameter of the aerosol generating article.

[0008] By using a thick substrate wrapper having a thickness of 50 micrometers or more, the peripheral portion of the aerosol-forming substrate can be replaced with the wrapper material of the thick wrapper without changing the outer diameter of the aerosol-generating article. The thick wrapper can compensate for the thin diameter of the aerosol-forming substrate portion so that the outer diameter of the aerosol-generating article does not decrease. The outermost peripheral portion of the aerosol-forming substrate may not be sufficiently heated due to the distance to the heating element and the limited heat transfer when the aerosol-generating article is heated by the internal heating element. The insufficiently heated portion of the aerosol-forming substrate may not be sufficiently heated to participate in aerosolization during use. Advantageously, the thick wrapper can replace the portion of the aerosol-forming substrate that is insufficiently heated. Thus, the amount of the aerosol-forming substrate can be reduced. A more efficient aerosol-generating article can be provided.

[0009] An aerosol-forming substrate containing at least 35 weight percent of an aerosol-forming agent can make it possible that the total amount of the aerosol-forming substrate required is less compared to an aerosol-forming substrate containing less aerosol-forming agent.

[0010] An aerosol-forming substrate containing at least 35 weight percent of an aerosol-forming agent can make aerosol formation easier compared to an article containing an aerosol-forming substrate with a lower aerosol-forming agent content. Thereby, it may be possible to operate the aerosol-generating article at a lower temperature. A more energy-efficient article can be provided.

[0011] The thick wrapper can reduce the diameter of the aerosol-forming portion surrounded by the thick wrapper. The thick wrapper can reduce the internal volume of the aerosol-forming portion surrounded by the thick wrapper. The reduction in the diameter of the aerosol-forming portion can improve the thermal contact between the aerosol-forming substrate and the susceptor provided within the aerosol-forming substrate portion. A more efficient aerosol-generating article can be provided.

[0012] An aerosol-forming substrate comprising an aerosol-forming agent content of at least 35% by weight may have a lower aerosolization temperature compared to an aerosol-forming substrate comprising less aerosol-forming agent. A more energy-efficient aerosol-generating article may be provided. At lower temperatures, the risk of aerosolization of potentially undesirable components may be reduced.

[0013] A thick wrapper may be more elastic against leakage of the aerosol-forming substrate, particularly the liquid or viscous components of the aerosol-forming agent, compared to a thin wrapper. A mechanically more stable aerosol-generating article may be provided for a heat-not-burn aerosol-forming substrate, particularly one containing a high level of liquid or aerosol-forming agent. As a result, swelling, visible soiling, and physical weakening of the aerosol-generating article may be reduced, even when a high level of wetting agent is included in the aerosol-forming substrate. This may be particularly advantageous in combination with an aerosol-forming substrate comprising an aerosol-forming agent content of at least 35% by weight. An aerosol generation that does not visibly change, or changes very little, during use may be provided.

[0014] A leak-resistant thick wrapper may be more rigid than a conventional thin wrapper. A thin wrapper may lose stability more quickly when immersed in liquid. A mechanically more robust aerosol-generating article may be provided, particularly in combination with an aerosol-forming substrate comprising an aerosol-forming agent content of at least 35% by weight. A mechanically more robust aerosol-generating article may be particularly advantageous when the aerosol-generating article is arranged to be inserted into the heating chamber of an aerosol-generating device.

[0015] An aerosol-generating article that can be used in an existing aerosol-generating device may be provided with an unchanged outer diameter of the aerosol-generating article.

[0016] The base wrapper may have a thickness of 60 micrometers or more, preferably 70 micrometers or more, more preferably 75 micrometers or more, more preferably 80 micrometers or more, more preferably 90 micrometers or more, more preferably 100 micrometers or more, more preferably 110 micrometers or more, more preferably 120 micrometers or more, more preferably 130 micrometers or more, more preferably 140 micrometers or more, more preferably 145 micrometers or more, more preferably 150 micrometers or more. The base wrapper may have a thickness of about 148 micrometers. The base wrapper may have a thickness of 143 micrometers to 153 micrometers. The base wrapper may have a thickness of 140 micrometers to 160 micrometers.

[0017] The base wrapper may have a uniform thickness that does not vary by more than about 30 micrometers, or more than about 20 micrometers, or more than about 10 micrometers, or more than about 5 micrometers, or more than about 2 micrometers at any point.

[0018] The ratio of the thickness of the base wrapper to the diameter of the aerosol-forming substrate portion is in the range of about 1:120 to about 1:20, or about 1:100 to about 1:30, or about 1:80 to about 1:35, or about 1:60 to about 1:40.

[0019] As used herein, the term "aerosol-forming substrate" refers to a substrate having the ability to release a volatile compound capable of forming an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. The aerosol-forming substrate may be in solid form or in liquid form. The aerosol-forming substrate may be solid or liquid, or may contain both solid and liquid components. The aerosol-forming substrate may be part of an aerosol-generating article. The terms "aerosol" and "vapor" are used interchangeably.

[0020] The aerosol-forming substrate may comprise one or more of tobacco, nicotine, an aerosol-forming film, a gel composition, and a flavorant.

[0021] The aerosol-forming substrate comprises at least 35 weight percent of one or more aerosol formers. The aerosol-forming substrate comprises at least 35 weight percent of one or more aerosol formers on a dry weight basis of the aerosol-forming substrate. Unless otherwise defined, all weight percents described herein are on a dry weight basis.

[0022] The aerosol former can be any suitable known compound or mixture of compounds that promotes the formation of a dense and stable aerosol during use. The aerosol former can promote the aerosol being substantially resistant to thermal decomposition at the temperatures typically applied during use of the aerosol-generating article. Suitable aerosol formers are, for example, polyhydric alcohols (such as triethylene glycol, 1,3-butanediol, propylene glycol, glycerin, etc.), esters of polyhydric alcohols (such as glycerol mono-, di-, or triacetate, etc.), aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate, dimethyl tetradecanedioate, etc.), and combinations thereof. It is preferred that one or more aerosol formers comprise one or both of glycerol and propylene glycol. One or more aerosol formers can consist of one or both of glycerol and propylene glycol. The aerosol-forming substrate preferably comprises glycerol. The terms "glycerin" and "glycerol" are used synonymously herein.

[0023] The aerosol-forming substrate may comprise up to 80 weight percent of aerosol former on a dry weight basis of the aerosol-forming substrate. The aerosol-forming substrate may comprise up to 60 weight percent of aerosol former on a dry weight basis of the aerosol-forming substrate. The aerosol-forming substrate may comprise up to 40 weight percent of aerosol former on a dry weight basis of the aerosol-forming substrate.

[0024] The aerosol-forming substrate may contain 35 wt% to 80 wt%, or 35 wt% to 60 wt%, or 35 wt% to 55 wt%, or 35 wt% to 50 wt%, or 35 wt% to 40 wt% of the aerosol-forming agent, based on the dry weight of the aerosol-forming substrate.

[0025] The total aerosol-forming agent content of the aerosol-forming substrate can be at least 40 wt%, preferably at least 45 wt%, more preferably at least 50 wt%, and even more preferably at least 55 wt%. The total aerosol-forming agent content of the aerosol-forming substrate can be 35 wt% to 75 wt%, preferably 40 wt% to 60 wt%, and more preferably 45 wt% to 55 wt%.

[0026] The aerosol-forming substrate may contain nicotine. The aerosol-forming substrate may contain one or more carboxylic acids. The aerosol-forming substrate may contain nicotine, one or more cellulose-based agents, one or more aerosol-forming agents, and one or more carboxylic acids.

[0027] The one or more carboxylic acids may be selected from fumaric acid, maleic acid, and malic acid. The one or more carboxylic acids may be selected from fumaric acid and maleic acid. The one or more carboxylic acids may be fumaric acid. The one or more carboxylic acids may have a pKa in water of 3.5 or less at 25°C. The aerosol-forming substrate may contain one or more carboxylic acids selected from acetic acid, benzoic acid, lactic acid, and levulinic acid.

[0028] The aerosol-forming substrate may have a total cellulose-based agent content of about 35% to 50% by weight. The aerosol-forming substrate may include one or more cellulose-based film-forming agents selected from carboxymethyl cellulose and hydroxypropyl methyl cellulose. The aerosol-forming substrate may include one or more cellulose-based reinforcing agents selected from cellulose fibers, microcrystalline cellulose, and cellulose powder.

[0029] The aerosol-forming substrate can be an aerosol-forming film. The aerosol-forming substrate can be a solid aerosol-forming film. The solid aerosol-forming film can be solid at room temperature. The solid aerosol-forming film can remain solid when heated to a temperature of 180°C to 350°C.

[0030] The aerosol-forming substrate can be provided in the form of a gel.

[0031] The aerosol-forming substrate may be substantially tobacco-free. The aerosol-forming substrate may be tobacco-free.

[0032] The aerosol-forming substrate may include one or more carboxylic acids and may have a total carboxylic acid content of 0.5% by weight or more. The aerosol-forming substrate may be free of iota-carrageenan or kappa-carrageenan.

[0033] The aerosol-forming substrate can be a solid aerosol-forming substrate. As used herein in connection with the present invention, the term "solid" is used to describe an aerosol-forming substrate that has a stable size and shape and does not flow at room temperature, which is about 23°C.

[0034] For example, the aerosol-forming substrate can remain solid when heated to a temperature of 180°C to 350°C, 200°C to 320°C, 220°C to 300°C, or 240°C to 280°C.

[0035] The aerosol-forming substrate can be an aerosol-forming film.

[0036] As used herein, the term "film" is used to describe a solid, layered element having a thickness that is less than its width or length. The film can be self-supporting. In other words, the film can have cohesive and mechanical properties such that it can be separated from the support surface even if it is obtained by casting a film-forming formulation on a support surface. Alternatively, the film can be disposed on a support or sandwiched between other materials. This can enhance the mechanical stability of the film.

[0037] The solid aerosol-forming substrate can be a solid aerosol-forming film.

[0038] The aerosol-forming film can contain one or more aerosol-forming substances as described herein. Preferably, the aerosol-forming substance contains or is glycerin. The aerosol-forming film can have an aerosol-forming substance content of at least 35 weight percent on a dry weight basis. Preferably, the aerosol-forming film has an aerosol-forming substance content of at least 40 weight percent on a dry weight basis. More preferably, the aerosol-forming film has an aerosol-forming substance content of at least 45 weight percent on a dry weight basis. Even more preferably, the aerosol-forming film has an aerosol-forming substance content of at least 50 weight percent on a dry weight basis.

[0039] Preferably, the aerosol-forming film has an aerosol-forming substance content of 80 weight percent or less on a dry weight basis. More preferably, the aerosol-forming film has an aerosol-forming substance content of 75 weight percent or less on a dry weight basis. Even more preferably, the aerosol-forming film has an aerosol-forming substance content of 70 weight percent or less on a dry weight basis.

[0040] The aerosol-forming substrate can be in the form of an aerosol-forming film comprising a cellulose-based film former, nicotine, and an aerosol former. The aerosol-forming film can further comprise a cellulose-based strengthening agent. The aerosol-forming film can further comprise water, preferably water at about 30 weight percent or less.

[0041] As used herein with respect to the present invention, the term "thickness" is used to describe the minimum dimension between opposing substantially parallel surfaces of a solid aerosol-forming film.

[0042] The solid aerosol-forming film can have a thickness of 0.05 millimeters or more, 0.1 millimeters or more, 0.2 millimeters or more, or 0.3 millimeters or more. The solid aerosol-forming film can have a thickness of 1.2 millimeters or less, 1 millimeter or less, 0.8 millimeters or less, 0.6 millimeters or less, or 0.4 millimeters or less.

[0043] The solid aerosol-forming film can have a basis weight of 85 grams per square meter or more, 100 grams per square meter or more, 120 grams per square meter or more, or 140 grams per square meter or more. The solid aerosol-forming film can have a basis weight of 300 grams per square meter or less, 280 grams per square meter or less, or 260 grams per square meter or less.

[0044] The solid aerosol-forming film can be formed by any suitable method. For example, the solid aerosol-forming film can be formed by batch casting, continuous casting, or extrusion.

[0045] The solid aerosol-forming film can be self-supporting. In other words, the properties of the solid aerosol-forming film can be such that the solid aerosol-forming film can be separated from the support surface even if the solid aerosol-forming film is formed by casting a slurry onto the support surface.

[0046] The solid aerosol-forming film may be formed on a support, or the solid aerosol-forming film may be sandwiched between other materials. Thereby, the mechanical stability of the solid aerosol-forming film can be enhanced. For example, the solid aerosol-forming film can be formed on a layered support.

[0047] The solid aerosol-forming film can be cut or otherwise divided into a plurality of strips or pieces that can be wrapped to form an aerosol-forming portion wrapped by a substrate wrapper.

[0048] The solid aerosol-forming film can be assembled before being inserted into the aerosol-forming portion. The solid aerosol-forming film can be textured. Thereby, the assembly of the solid aerosol-forming film before being inserted into the aerosol-forming portion becomes easy.

[0049] As used herein in connection with the present invention, the term "textured" is used to describe a solid aerosol-forming film that has been crimped, embossed, debossed, perforated, or otherwise deformed. The textured solid aerosol-forming film can include a plurality of spaced depressions, protrusions, perforations, or combinations thereof.

[0050] The solid aerosol-forming film can be crimped.

[0051] As used herein in connection with the present invention, the term "crimped" is intended to be synonymous with the term "creased" and is used to describe a solid aerosol-forming film having a plurality of substantially parallel ridges or waveforms.

[0052] The solid aerosol-forming film can be directly incorporated into the aerosol-forming portion.

[0053] The solid aerosol-forming film can be applied to a layered support before being incorporated into the aerosol-forming portion. For example, the solid aerosol-forming film can be applied to the surface of a sheet material. Suitable sheet materials for use as the layered support include, but are not limited to, paper, cardboard, and homogenized plant materials. For example, the solid aerosol-forming film can be applied to a paper sheet, an aluminum-coated paper sheet, or a polyethylene-coated paper sheet.

[0054] The layered support to which the solid aerosol-forming film is applied can be cut or otherwise divided into a plurality of strips or pieces as described above.

[0055] The layered support to which the solid aerosol-forming film is applied can be assembled as described above.

[0056] The layered support to which the solid aerosol-forming film is applied can be textured as described above.

[0057] As used herein with respect to the present invention, the term "aerosol former" is used to describe, in use, a compound that facilitates the formation of an aerosol and is preferably substantially resistant to thermal decomposition at the operating temperature of an aerosol-generating system comprising an aerosol-generating article or a solid aerosol-forming substrate.

[0058] Examples of suitable aerosol formers include polyhydric alcohols (such as 1,3-butanediol, glycerin, 1,3-propanediol, propylene glycol, and triethylene glycol), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids (such as dimethyl dodecanedioate and dimethyl tetradecanedioate).

[0059] The aerosol-forming substrate has a total aerosol-forming agent content of 35 wt% or more. The aerosol-forming substrate may have a total aerosol-forming agent content of 40 wt% or more, or 45 wt% or more, or 50 wt% or more.

[0060] As used herein with respect to the present invention, the term "total aerosol-forming agent content" is used to describe the combined content of all aerosol-forming agents in the aerosol-forming substrate.

[0061] The solid aerosol-forming substrate may have a total aerosol-forming agent content of 46 wt% or more, 48 wt% or more, 50 wt% or more, or 52 wt% or more.

[0062] The solid aerosol-forming substrate may have a total aerosol-forming agent content of 62 wt% or less, 60 wt% or less, 58 wt% or less, 56 wt% or less, or 54 wt% or less.

[0063] The solid aerosol-forming substrate may have a total aerosol-forming agent content of 42 wt% to 62 wt%, 46 wt% to 60 wt%, 46 wt% to 58 wt%, 46 wt% to 56 wt%, or 46 wt% to 54 wt%.

[0064] Preferably, the solid aerosol-forming substrate contains one or more polyhydric alcohols.

[0065] The solid aerosol-forming substrate may have a total polyhydric alcohol content of 45 wt% or more, 46 wt% or more, 48 wt% or more, 50 wt% or more, or 52 wt% or more.

[0066] Preferably, the solid aerosol-forming substrate comprises one or more polyhydric alcohols selected from 1,3-butanediol, glycerin, 1,3-propanediol, propylene glycol, and triethylene glycol.

[0067] More preferably, the solid aerosol-forming substrate comprises one or more polyhydric alcohols selected from glycerin and propylene glycol. Most preferably, the solid aerosol-forming substrate comprises glycerin.

[0068] The solid aerosol-forming substrate may comprise one or more carboxylic acids having a pKa in water of 3.5 or less at 25°C.

[0069] As used herein in connection with the present invention, the term "carboxylic acid having a pKa in water of 3.5 or less at 25°C" is used to describe monobasic carboxylic acids having a pKa in water of 3.5 or less at 25°C and polybasic carboxylic acids having a pKa1 in water of 3.5 or less at 25°C.

[0070] The solid aerosol-forming substrate may have a total carboxylic acid content of 1 wt% or more, 1.5 wt% or more, or 2 wt% or more.

[0071] The solid aerosol-forming substrate may have a total carboxylic acid content of 8 wt% or less, 6 wt% or less, or 4 wt% or less.

[0072] The solid aerosol-forming substrate may have a total carboxylic acid content of 0.5 wt% to 8 wt%, 1 wt% to 6 wt%, or 2 wt% to 4 wt%.

[0073] The molar ratio of total carboxylic acid to nicotine in the solid aerosol-forming substrate can be 0.5:1 to 5:1, 0.5:1 to 4.5:1, 0.5:1 to 4:1, or 0.5:1 to 3.5:1.

[0074] The solid aerosol-forming substrate may contain one or more cellulose-based agents.

[0075] As used herein in connection with the present invention, the term "cellulose-based agent" is used to describe a cellulose-based substance. The term "cellulose-based film-forming agent" may be used to describe a cellulose polymer that has the ability to form a continuous film, either by itself or in the presence of an auxiliary thickener.

[0076] Examples of cellulose-based agents include cellulose-based film-forming agents, cellulose-based strengthening agents, and cellulose-based binders.

[0077] As used herein in connection with the present invention, the term "total cellulose-based agent" is used to describe the total content of all cellulose-based agents in the solid aerosol-forming substrate. For example, if the solid aerosol-forming substrate contains a plurality of cellulose-based agents consisting of a cellulose-based film-forming agent, a cellulose-based strengthening agent, and a cellulose-based binder, the term "total cellulose-based agent content" describes the combined cellulose-based film-forming agent content, cellulose-based strengthening agent content, and cellulose-based binder content of the solid aerosol-forming substrate.

[0078] The solid aerosol-forming substrate may have a total cellulose-based agent content of 25 weight percent or more, or 30 weight percent or more. Preferably, the solid aerosol-forming substrate has a total cellulose-based agent content of 35 weight percent or more. The solid aerosol-forming substrate may have a total cellulose-based agent content of 36 weight percent or more, 38 weight percent or more, or 40 weight percent or more.

[0079] The solid aerosol-forming substrate may have a total cellulose-based agent content of 52 weight percent or less, 50 weight percent or less, 48 weight percent or less, 46 weight percent or less, or 44 weight percent or less.

[0080] The solid aerosol-forming substrate may have a total cellulose-based agent content of 35 wt% to 52 wt%, 35 wt% to 50 wt%, 35 wt% to 48 wt%, 35 wt% to 46 wt%, or 35 wt% to 44 wt%.

[0081] The solid aerosol-forming substrate may include one or more cellulose-based film-forming agents.

[0082] As used herein in connection with the present invention, the term "cellulose-based film-forming agent" is used to describe a cellulose polymer that has the ability to form a continuous film, either by itself or in the presence of an auxiliary thickening agent.

[0083] Advantageously, the solid aerosol-forming substrate may include one or more cellulose-based film-forming agents selected from carboxymethyl cellulose (CMC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), hydroxyethyl methyl cellulose (HEMC), hydroxypropyl cellulose (HPC), hydroxypropyl methyl cellulose (HPMC), and methyl cellulose (MC). Preferably, the solid aerosol-forming substrate includes carboxymethyl cellulose (CMC) and hydroxypropyl methyl cellulose (HPMC).

[0084] Preferably, the cellulose-based film-forming agent is selected from the group consisting of hydroxypropyl methyl cellulose (HPMC), methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl methyl cellulose (HEMC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), and combinations thereof.

[0085] More preferably, the cellulose-based film-forming agent is selected from the group consisting of hydroxypropyl methyl cellulose (HPMC), methyl cellulose (MC), ethyl cellulose (EC), and combinations thereof.

[0086] In a particularly preferred embodiment, the cellulose-based film-forming agent is HPMC.

[0087] One or more cellulose-based film-forming agents can act as binders for the solid aerosol-forming substrate.

[0088] The solid aerosol-forming substrate can have a total cellulose-based film-forming agent of 15 weight percent or more, 20 weight percent or more, or 25 weight percent or more.

[0089] The solid aerosol-forming substrate can have a total cellulose-based film-forming agent content of 40 weight percent or less, 35 weight percent or less, or 30 weight percent or less.

[0090] The solid aerosol-forming substrate can have a total cellulose-based film-forming agent content of 10 weight percent to 40 weight percent, 15 weight percent to 35 weight percent, or 15 weight percent to 30 weight percent. The aerosol-forming film can have a cellulose-based film-forming agent content of 10 weight percent to 40 weight percent, or 15 weight percent to 35 weight percent, or 20 weight percent to 30 weight percent on a dry weight basis.

[0091] The solid aerosol-forming substrate can include one or more cellulose-based strengthening agents.

[0092] Including one or more cellulose-based strengthening agents in the solid aerosol-forming substrate can advantageously increase the tensile strength of the solid aerosol-forming substrate. In particular, when the solid aerosol-forming substrate is a solid aerosol-forming film, including one or more cellulose-based strengthening agents in the solid aerosol-forming substrate can advantageously increase the tensile strength of the solid aerosol-forming film. A solid aerosol-forming substrate having a high tensile strength can advantageously have a lower likelihood of deterioration or breakage during manufacture and storage.

[0093] Advantageously, the solid aerosol forming substrate may comprise one or more cellulose-based reinforcing agents selected from cellulose fibers, cellulose powder, and microcrystalline cellulose (MCC). Preferably, the cellulose-based reinforcing agent is selected from the group consisting of cellulose fibers, microcrystalline cellulose (MCC), cellulose powder, and combinations thereof.

[0094] Preferably, the solid aerosol forming substrate comprises cellulose fibers. The cellulose fibers can be particularly effective in increasing the tensile strength of the solid aerosol forming substrate.

[0095] The aerosol forming film may have a cellulose-based reinforcing agent content of from 0.5 weight percent to 40 weight percent, or from 5 weight percent to 30 weight percent, or from 10 weight percent to 25 weight percent, based on dry weight.

[0096] The solid aerosol forming substrate may have a total cellulose-based reinforcing agent content of 5 weight percent or more, 10 weight percent or more, or 15 weight percent or more.

[0097] As used herein in connection with the present invention, the term "total cellulose-based reinforcing agent content" is used to describe the total content of all cellulose-based reinforcing agents in the solid aerosol forming substrate.

[0098] The solid aerosol forming substrate may have a total cellulose-based reinforcing agent content of 30 weight percent or less, 25 weight percent or less, or 20 weight percent or less.

[0099] The solid aerosol forming substrate may have a total cellulose-based reinforcing agent content of 5 weight percent to 30 weight percent, 5 weight percent to 25 weight percent, or 5 weight percent to 20 weight percent.

[0100] The aerosol forming film may further comprise carboxymethyl cellulose, preferably sodium carboxymethyl cellulose.

[0101] The aerosol-forming film may have a carboxymethyl cellulose content of 1 wt% to 15 wt%, or 2 wt% to 12 wt%, or 4 wt% to 10 wt% on a dry weight basis.

[0102] The solid aerosol-forming substrate may contain water.

[0103] The solid aerosol-forming substrate may have a water content of 5 wt% or more, 10 wt% or more, 15 wt% or more, or 17 wt% or more based on the total weight of the solid aerosol-forming substrate.

[0104] The solid aerosol-forming substrate may have a water content of 35 wt% or less, 30 wt% or less, or 25 wt% or less based on the total weight of the solid aerosol-forming substrate.

[0105] The solid aerosol-forming substrate may have a water content of 5 wt% to 35 wt%, 5 wt% to 30 wt%, or 5 wt% to 25 wt% based on the total weight of the solid aerosol-forming substrate.

[0106] The solid aerosol-forming substrate may contain one or more non-cellulosic thickeners.

[0107] As used herein in connection with the present invention, the term "non-cellulosic thickener" is used to describe a non-cellulosic substance that increases the viscosity of an aqueous or non-aqueous liquid composition without substantially modifying other properties of the liquid composition when added thereto. One or more non-cellulosic thickeners may increase stability and improve the suspension of components in the liquid composition. The thickener may also be referred to as a "thickener", a "rheology modifier", or a "viscosifying agent".

[0108] The solid aerosol-forming substrate may include one or more non-cellulosic thickeners selected from alginate, gellan gum, guar gum, gum arabic, locust bean gum, pectin, starch, and xanthan gum.

[0109] The solid aerosol-forming substrate may have a total cellulosic thickener of 1 wt% or more, 2 wt% or more, or 3 wt% or more.

[0110] The solid aerosol-forming substrate may have a total non-cellulosic thickener content of 10 wt% or less, 8 wt% or less, or 6 wt% or less.

[0111] The solid aerosol-forming substrate may have a total non-cellulosic thickener content of 1 wt% to 10 wt%, 1 wt% to 8 wt%, or 1 wt% to 6 wt%.

[0112] The solid aerosol-forming substrate may include one or more flavoring agents.

[0113] Suitable flavoring agents are known in the art and include, but are not limited to, menthol.

[0114] As used herein in connection with the present invention, the term "menthol" is used to describe the compound 2-isopropyl-5-methylcyclohexanol in any of its isomers.

[0115] The solid aerosol-forming substrate may have a total flavoring agent content of 0.5 wt% or more, 1 wt% or more, 2 wt% or more, or 3 wt% or more.

[0116] The solid aerosol-forming substrate may have a total flavoring agent content of 6 wt% or less, 5 wt% or less, or 4 wt% or less.

[0117] The solid aerosol-forming substrate may have a total flavorant content of from 0.5 wt% to 6 wt%, from 0.5 wt% to 5 wt%, or from 0.5 wt% to 4 wt%.

[0118] The solid aerosol-forming substrate may have a total flavorant content of from 1 wt% to 6 wt%, from 1 wt% to 5 wt%, or from 1 wt% to 4 wt%.

[0119] The solid aerosol-forming substrate may be a substantially tobacco-free solid aerosol-forming substrate.

[0120] As used herein in the context of the present invention, the term "substantially tobacco-free solid aerosol-forming substrate" is used to describe a solid aerosol-forming substrate having a tobacco content of less than 1 wt%. For example, the solid aerosol-forming substrate may have a tobacco content of less than 0.75 wt%, less than 0.5 wt%, or less than 0.25 wt%.

[0121] The solid aerosol-forming substrate may be a tobacco-free aerosol-forming film.

[0122] As used herein in the context of the present invention, the term "tobacco-free solid aerosol-forming substrate" is used to describe a solid aerosol-forming substrate having a tobacco content of 0 wt%.

[0123] The aerosol-forming film preferably contains nicotine.

[0124] As used herein in the context of the present invention, the term "nicotine" is used to describe nicotine, nicotine base, or a nicotine salt. In embodiments where the aerosol-forming film contains nicotine base or a nicotine salt, the amounts of nicotine recited herein are the amounts of free base nicotine or protonated nicotine, respectively.

[0125] The aerosol-forming film may contain natural nicotine or synthetic nicotine.

[0126] The nicotine-containing aerosol-forming substrate may be a nicotine salt matrix.

[0127] The aerosol-forming film may contain one or more monobasic nicotine salts.

[0128] As used herein in connection with the present invention, the term "monobasic nicotine salt" is used to describe a nicotine salt of a monobasic acid.

[0129] Preferably, the aerosol-forming film contains at least 0.5 weight percent nicotine on a dry weight basis. More preferably, the aerosol-forming film contains at least 1 weight percent nicotine on a dry weight basis. Even more preferably, the aerosol-forming film contains at least 2 weight percent nicotine on a dry weight basis. Additionally, or alternatively, the aerosol-forming film preferably contains less than 10 weight percent nicotine on a dry weight basis. More preferably, the aerosol-forming film contains less than 8 weight percent nicotine on a dry weight basis. Even more preferably, the aerosol-forming film contains less than 6 weight percent nicotine on a dry weight basis.

[0130] For example, the aerosol-forming film may contain from 0.5 weight percent to 10 weight percent nicotine, or from 1 weight percent to 8 weight percent nicotine, or from 2 weight percent to 6 weight percent nicotine on a dry weight basis.

[0131] The aerosol-forming film may be a substantially tobacco-free aerosol-forming film.

[0132] In a preferred embodiment, the aerosol-forming film contains an acid. More preferably, the aerosol-forming film contains one or more organic acids. Even more preferably, the aerosol-forming film contains one or more carboxylic acids. In a particularly preferred embodiment, the acid is lactic acid, benzoic acid, fumaric acid or levulinic acid.

[0133] Preferably, the aerosol-forming film contains 0.25 weight percent to 3.5 weight percent acid, or 0.5 weight percent to 3 weight percent acid, or 1 weight percent to 2.5 weight percent acid, based on dry weight.

[0134] The aerosol-forming film can have a thickness of from about 0.1 millimeter to about 1 millimeter, more preferably from about 0.1 millimeter to about 0.75 millimeter, even more preferably from about 0.1 millimeter to about 0.5 millimeter. In a particularly preferred embodiment, a layer of the film-forming composition having a thickness of from about 50 micrometers to 400 micrometers, more preferably from about 100 micrometers to 200 micrometers, is formed.

[0135] The aerosol-forming film can optionally be provided on a suitable carrier element.

[0136] The aerosol-forming substrate can contain a gel. The aerosol-forming substrate can contain a gel composition containing nicotine, at least one gelling agent and an aerosol former. The gel composition preferably does not substantially contain tobacco.

[0137] The preferred weight range of nicotine in the gel composition is the same as that defined above in relation to the aerosol-forming film.

[0138] The gel composition preferably contains, on a dry weight basis, at least 50 weight percent of an aerosol former, more preferably at least 60 weight percent of an aerosol former, and even more preferably at least 70 weight percent of an aerosol former. The gel composition can contain up to 80 weight percent of an aerosol former. The aerosol former in the gel composition is preferably glycerol.

[0139] The gel composition preferably contains at least one gelling agent. Preferably, the gel composition contains a total amount of gelling agent in the range of about 0.4 weight percent to about 10 weight percent, or about 0.5 weight percent to about 8 weight percent, or about 1 weight percent to about 6 weight percent, or about 2 weight percent to about 4 weight percent, or about 2 weight percent to about 3 weight percent.

[0140] The term "gelling agent" refers to a compound that, when added in an amount of about 0.3 weight percent to a homogeneous mixture of 50 weight percent water / 50 weight percent glycerol, forms a solid medium or support matrix leading to a gel. Examples of gelling agents include, but are not limited to, hydrogen bond cross-linked gelling agents and ion cross-linked gelling agents.

[0141] The term "hydrogen bond cross-linked gelling agent" refers to a gelling agent that forms non-covalent cross-links or physical cross-links via hydrogen bonds.

[0142] The hydrogen bond cross-linked gelling agent may include one or more of galactomannan, gelatin, agarose, konjac gum, or agar. The hydrogen bond cross-linked gelling agent may preferably include agar.

[0143] The term "ion cross-linked gelling agent" refers to a gelling agent that forms non-covalent cross-links or physical cross-links via ionic bonds.

[0144] The ionic crosslinking gelling agent may include low acyl gellan, pectin, kappa carrageenan, iota carrageenan, or alginate. It is preferable that the ionic crosslinking gelling agent may include low acyl gellan.

[0145] The gelling agent may include one or more biopolymers. The biopolymer may be formed of a polysaccharide.

[0146] Examples of biopolymers include gellan gum (natural gellan gum, low acyl gellan gum, high acyl gellan gum, low acyl gellan gum is preferred), xanthan gum, alginate (algic acid), agar, guar gum, etc. The composition may preferably contain xanthan gum in some cases. The composition may contain two biopolymers. The composition may contain three biopolymers. The composition may contain two biopolymers in substantially equal weights. The composition may contain three biopolymers in substantially equal weights.

[0147] The gel composition may further contain a thickening agent. The thickening agent combined with the hydrogen bond crosslinking gelling agent and the ionic crosslinking gelling agent surprisingly supports the solid matrix and maintains the gel composition even when the gel composition contains a high level of glycerol.

[0148] The term "thickening agent" refers to a compound that increases the viscosity without causing gel formation and keeps the mixture in a fluid state when uniformly added in an amount of 0.3 weight percent in a mixture of 50 weight percent water / 50 weight percent glycerol at 25°C.

[0149] The gel composition preferably contains a thickening agent in the range of about 0.2 weight percent to about 5 weight percent, or about 0.5 weight percent to about 3 weight percent, or about 0.5 weight percent to about 2 weight percent, or about 1 weight percent to about 2 weight percent.

[0150] The thickener may include one or more of xanthan gum, carboxymethyl cellulose, microcrystalline cellulose, methyl cellulose, gum arabic, guar gum, lambda carrageenan, or starch. Preferably, the thickener may include xanthan gum.

[0151] The gel composition may further include a divalent cation. Preferably, the divalent cation includes calcium ions such as calcium lactate in solution. Divalent cations (such as calcium ions) can assist in the gel formation of a composition containing a gelling agent such as an ionic crosslinking gelling agent. The ionic effect may assist in gel formation. The divalent cation may be present in the gel composition in the range of about 0.1 to about 1 weight percent, or at about 0.5 weight percent.

[0152] The gel composition may further include an acid. The acid may include a carboxylic acid. The carboxylic acid may include a ketone group. Preferably, the carboxylic acid may include a ketone group having less than about 10 carbon atoms, or less than about 6 carbon atoms or less than about 4 carbon atoms such as levulinic acid or lactic acid. Preferably, this carboxylic acid has three carbon atoms (such as lactic acid).

[0153] The gel composition preferably includes some water. When the composition includes some water, the gel composition is more stable.

[0154] Preferably, the gel composition includes from about 8 weight percent to about 32 weight percent water, or from about 15 weight percent to about 25 weight percent water, or from about 18 weight percent to about 22 weight percent water, or about 20 weight percent water.

[0155] Preferably, when using the gel composition, the aerosol-forming substrate includes a porous medium filled with the gel composition. The advantage of the porous medium loaded with the gel composition is that the gel composition is retained within the porous medium, which can assist in the manufacture, storage, or transportation of the gel composition. This can help maintain the desired shape of the gel composition, especially during manufacture, transportation, or use.

[0156] The term "porous" is used herein to refer to a material that provides a plurality of pores or openings that allow air to pass through the material.

[0157] The porous medium may be any suitable porous material that can hold or retain the gel composition. Ideally, the porous medium can allow the gel composition to move therein. In certain embodiments, the porous medium includes natural materials, synthetic, or semi-synthetic, or combinations thereof. In certain embodiments, the porous medium includes sheet materials, foams, or fibers, such as bar fibers, or combinations thereof. In certain embodiments, the porous medium includes woven fabrics, non-woven fabrics, or extruded materials, or combinations thereof. The porous medium preferably includes cotton, paper, viscose, PLA, or cellulose acetate, or combinations thereof. The porous medium preferably includes a sheet material, such as cotton or cellulose acetate. In a particularly preferred embodiment, the porous medium includes a sheet made from cotton fibers.

[0158] The porous medium may be crimped or shredded. The porous medium may be in the form of a sheet, thread, or tubular element.

[0159] The aerosol-forming substrate may be added with a portion of plant material, such as tobacco material, as long as the aerosol-forming agent content does not become less than 35 weight percent.

[0160] The aerosol-forming substrate may contain tobacco particles. For the purposes of the present invention, the term "tobacco particles" refers to particles of any plant member of the Nicotiana species. The term "tobacco particles" encompasses ground or powdered tobacco leaf lamina, ground or powdered tobacco leaf stems, tobacco dust, tobacco fines, and other particulate tobacco by-products formed during the processing, handling, and shipping of tobacco. In a preferred embodiment, substantially all of the tobacco particles are derived from tobacco leaf lamina. In contrast, isolated nicotine and nicotine salts, while being compounds derived from tobacco, are not considered tobacco particles for the purposes of the present invention and are not included in the proportion of particulate plant material.

[0161] The aerosol-forming substrate may contain plant material and an aerosol former. The plant material may be plant material containing an alkaloid, more preferably plant material containing nicotine, and even more preferably tobacco-containing material.

[0162] An alkaloid is a class of natural nitrogen-containing organic compounds. Alkaloids are mainly found in plants, but are also found in bacteria, fungi, and animals. Examples of alkaloids include, but are not limited to, caffeine, nicotine, theobromine, atropine, and tubocurarine. A preferred alkaloid is nicotine, which may be found in tobacco.

[0163] As used herein, the term "tobacco material" is used to describe any material containing tobacco, including but not limited to tobacco leaves, tobacco veins, tobacco stems, tobacco petioles, tobacco dust, expanded tobacco, reconstituted tobacco material, and homogenized tobacco material.

[0164] As used herein, the term "flavorant" refers to a composition having sensory stimulating properties that provide a sensory experience to the user, for example, to enhance the flavor of an aerosol. A flavorant can be used, for example, to deliver taste (flavor), smell (odor), or both taste and smell to the user when the aerosol is inhaled.

[0165] The base wrapper can have a density of 800 kilograms or less per cubic meter. The density of the base wrapper is 750 kilograms or less per cubic meter, preferably 700 kilograms or less per cubic meter, more preferably 650 kilograms or less per cubic meter, more preferably 600 kilograms or less per cubic meter, more preferably 550 kilograms or less per cubic meter, more preferably 500 kilograms or less per cubic meter, more preferably 450 kilograms or less per cubic meter per cubic meter, and can be. The density of the base wrapper can be 400 kilograms or less per cubic meter, preferably 350 kilograms or less per cubic meter, and more preferably about 320 kilograms per cubic meter.

[0166] The density of the base wrapper may be 400 kilograms or less per cubic meter, and the base wrapper may have a thickness of 60 micrometers or more, preferably 70 micrometers or more, more preferably 75 micrometers or more, more preferably 80 micrometers or more, more preferably 90 micrometers or more, more preferably 100 micrometers or more, more preferably 110 micrometers or more, more preferably 120 micrometers or more, more preferably 130 micrometers or more, more preferably 140 micrometers or more, more preferably 145 micrometers or more, and more preferably 150 micrometers or more. The base wrapper may have a thickness of about 148 micrometers. The density of the base wrapper may be 400 kilograms or less per cubic meter, and the base wrapper may have a thickness of 143 micrometers to 153 micrometers. The density of the base wrapper may be 400 kilograms or less per cubic meter, and the base wrapper may have a thickness of 140 micrometers to 160 micrometers.

[0167] The basis weight of the base wrapper may be less than 60 grams per square meter. The basis weight of the base wrapper may be more than 28 grams per square meter and less than 60 grams per square meter. The basis weight of the base wrapper may be more than 45 grams per square meter and less than 60 grams per square meter.

[0168] The basis weight of the base wrapper may be less than 50 grams per square meter. The basis weight of the base wrapper may be more than 28 grams per square meter and less than 50 grams per square meter. The basis weight of the base wrapper may be more than 45 grams per square meter and less than 50 grams per square meter. The basis weight of the base wrapper may be about 48 grams per square meter.

[0169] The base wrapper may have a thickness greater than 145 micrometers and a density of 400 kilograms or less per cubic meter.

[0170] The base wrapper may include one or more perforations or may not include any perforations.

[0171] The base wrapper may exhibit a permeability of more than 10 Coresta units, more than 20 Coresta units, more than 50 Coresta units, more than 100 Coresta units, more than 500 Coresta units, more than 1000 Coresta units, more than 1500 Coresta units, more than 2000 Coresta units, more than 2500 Coresta units, more than 3000 Coresta units, more than 3500 Coresta units, or more than 4000 Coresta units. The base wrapper may exhibit a permeability of 10 to 10,000 Coresta units, preferably 50 to 8000 Coresta units, more preferably 100 to 5000 Coresta units. The base wrapper may exhibit a permeability of 4000 to 4800 Coresta units, preferably 4200 to 4600 Coresta units, more preferably 4300 to 4500 Coresta units.

[0172] The base wrapper may have a thickness of more than 145 micrometers, a density of 400 kilograms or less per cubic meter, and a wrapper permeability of 50 to 5000 C.U., preferably 4200 to 4600 C.U., more preferably 4300 to 4500 C.U.

[0173] The permeability of the base wrapper can be determined using the international standard test method ISO2965:2009, and the result can be presented as cubic centimeters per minute per square centimeter and can be referred to as "C.U.".

[0174] The aerosol generating article may comprise an additional wrapper surrounding the base wrapper. The additional wrapper may exhibit a wrapper permeability of less than 100 C.U., less than 80 C.U., less than 50 C.U., less than 40 C.U., or less than 30 C.U. The permeability of the additional wrapper may be less than that of the base wrapper. The permeability of the additional wrapper may be less than 1%, 2%, 5%, 10%, or 20% of the permeability of the base wrapper. The permeability of the additional wrapper may be less than 50 C.U., and the permeability of the base wrapper may be 4000 to 4800 C.U., preferably 4200 to 4600 C.U., more preferably 4300 to 4500 C.U. The additional wrapper may be the tipping wrapper described herein. The additional wrapper may be a combination wrapper. Advantageously, the additional wrapper may reduce the overall permeability when a base wrapper with high permeability is used.

[0175] The base wrapper may or may not be embossed. The base wrapper may be both perforated and embossed.

[0176] The term "embossing" is used herein to refer to protrusions formed on the surface of the wrapper. These protrusions can be engraved, shaped, or stamped onto the wrapper. A portion of the wrapper with such embossing is said to be embossed.

[0177] The base wrapper may include an embossed portion. The embossed portion of the base wrapper may have one embossing. The embossed portion of the base wrapper may have multiple embossings. One or more embossings may have a depth of 0.07 millimeters to 0.21 millimeters, preferably 0.10 millimeters to 0.18 millimeters, more preferably 0.12 millimeters to 0.16 millimeters. Each embossing may also have a pitch of 0.2 millimeters to 0.4 millimeters, preferably 0.25 millimeters to 0.35 millimeters, more preferably 0.275 millimeters to 0.325 millimeters.

[0178] The base wrapper may have a roughness of about 50 Bekk seconds to about 1000 Bekk seconds, preferably about 100 Bekk seconds to about 200 Bekk seconds. The roughness expressed in Bekk seconds can be measured by a standard test using a BEKK Smoothness Tester that generates a vacuum and measures the time it takes for the vacuum to drop from 50.66 kPa to 48.00 kPa. This test is approved by the international standard ISO5627.

[0179] As used herein, "total density of the aerosol-forming substrate portion" refers to the total mass of the material received within the volume enclosed by the base wrapper divided by the volume enclosed by the base wrapper. The mass of the base wrapper itself and any optional additional wrapper surrounding the base wrapper is not considered. The volume of the base wrapper itself and any optional additional wrapper surrounding the base wrapper is not considered.

[0180] The total density of the aerosol-forming substrate part can be determined after conditioning the aerosol-generating article in accordance with ISO standard 3402:1999. The aerosol-forming substrate is removed from the aerosol-forming substrate part and weighed. If a susceptor is present, the susceptor is also removed from the aerosol-forming substrate part and weighed. The internal volume of the aerosol-forming substrate part is determined. This can be done, for example, by laser measurement. The internal volume of the aerosol-forming substrate part generally corresponds to the cylindrical volume within the substrate wrapper. The total density of the aerosol-forming substrate part is calculated by dividing the sum of the mass of the aerosol-forming substrate and, if present, the mass of the susceptor by the internal volume of the substrate part. This can be repeated 20 times for 20 different individual aerosol-generating articles in order to accept an average value.

[0181] As used herein, the "total density of the aerosol-generating article at the longitudinal position of the aerosol-forming substrate part" refers to the total mass of the material received within the volume defined by the average cross-sectional area of the aerosol-generating article along the length of the aerosol-forming substrate part, divided by the said volume. The mass of each of the aerosol-forming substrate, any optional susceptor, the substrate wrapper, and one or more optional additional wrappers surrounding the substrate wrapper is considered. The volume of each of the substrate wrapper itself and one or more optional additional wrappers surrounding the substrate wrapper is considered.

[0182] The "total density of the aerosol-generating article at the longitudinal position of the aerosol-forming substrate part" can be determined after conditioning the aerosol-generating article in accordance with ISO standard 3402:1999.

[0183] The thickness of the base wrapper can be determined in accordance with ISO 534:2011. The density of the base wrapper can be determined in accordance with ISO 534:2011. The thickness of the base wrapper can be determined in accordance with ASTM E252-06(2021)e1. Generally, for an embossed base wrapper, the local thickness at the position of embossing may be smaller than the thickness at a position without embossing. As used herein, for an embossed wrapper, the thickness of the base wrapper refers to the thickness at a position without embossing. For an embossed wrapper, the thickness of the base wrapper can be determined before the wrapper is embossed.

[0184] Unless otherwise defined, all measurements described herein are performed after adjusting the sample in accordance with ISO standard 3402:1999.

[0185] The density of the base wrapper can be calculated by dividing the basis weight of the base wrapper by the thickness of the base wrapper. The basis weight, also referred to as grammage, refers to the mass of the base wrapper per sheet size and is usually expressed in grams per square meter. The basis weight can be obtained, for example, by weighing a 1 square meter sheet of the base wrapper.

[0186] When referring to the base wrapper, the term "lightweight" as used herein means that the density of the base wrapper is 800 kilograms per cubic meter or less, preferably 750 kilograms per cubic meter or less, more preferably 700 kilograms per cubic meter or less, more preferably 650 kilograms per cubic meter or less, more preferably 600 kilograms per cubic meter or less, more preferably 550 kilograms per cubic meter or less, more preferably 500 kilograms per cubic meter or less, more preferably 450 kilograms per cubic meter or less, more preferably 400 kilograms per cubic meter or less, more preferably 350 kilograms per cubic meter or less, and more preferably about 320 kilograms per cubic meter.

[0187] When referring to the base wrapper, the term "thick" as used herein means that the thickness of the base wrapper is 50 micrometers or more, preferably 60 micrometers or more, more preferably 70 micrometers or more, more preferably 75 micrometers or more, more preferably 80 micrometers or more, more preferably 90 micrometers or more, more preferably 100 micrometers or more, more preferably 110 micrometers or more, more preferably 120 micrometers or more, more preferably 130 micrometers or more, more preferably 140 micrometers or more, more preferably 145 micrometers or more, and more preferably 150 micrometers or more.

[0188] The base wrapper can extend along the entire length of the aerosol-forming substrate portion in a direction along the longitudinal axis of the aerosol-generating article. The base wrapper can extend along at least 40 percent, preferably at least 50 percent, more preferably at least 60 percent, more preferably at least 70 percent, more preferably at least 80 percent, more preferably at least 90 percent, and more preferably at least 95 percent of the length of the aerosol-forming substrate portion in a direction along the longitudinal axis of the aerosol-generating article.

[0189] The substrate wrapper may be in direct physical contact with the aerosol-forming substrate. In that case, there is no layer of material between the substrate wrapper and the aerosol-forming substrate.

[0190] The substrate wrapper can be formed from a single continuous material sheet. The single continuous sheet can be wrapped around the aerosol-forming substrate portion in approximately one wrap. Generally, the single continuous sheet can be wrapped around the substrate portion in slightly more than two wraps to form an overlapping region of the opposing end portions of the substrate wrapper. The thickness of the wrapper is not measured in the overlapping region. Thus, the substrate wrapper formed from a single continuous material sheet can include only a single layer, excluding any optional overlapping regions, if present.

[0191] The substrate wrapper can be formed from a single continuous sheet that is wrapped around the aerosol-forming substrate portion in at least slightly more than two wraps. In that case, the two or more layers of the substrate wrapper are wrapped around the aerosol-forming substrate portion without considering the additional overlapping region formed by the overlapping opposing end portions of the wrapper. In that case, the thickness of the substrate wrapper can be obtained by multiplying the thickness of the individual layer, i.e., the thickness of the sheet, by the number of wraps. The thickness of the substrate wrapper cannot be obtained by multiplying the thickness of the individual layer by the number of wraps of the overlapping region formed by the overlapping opposing end portions of the wrapper. None of the individual layers extends beyond the end of the aerosol-forming substrate portion in the longitudinal direction of the aerosol-generating article.

[0192] The substrate wrapper may include one or more of cardboard, plastic, and metal foil.

[0193] The substrate wrapper may include one or more of cellulose-based materials such as paper, wood, fabric, natural fibers, and artificial fibers. The substrate wrapper may include a paper layer. The substrate wrapper may be made of a single paper sheet. The substrate wrapper may include a single paper layer wrapped around the aerosol-forming substrate portion, excluding any optional overlapping portions. The substrate wrapper may be made of a single paper sheet wrapped around the aerosol-forming substrate portion two or more times, resulting in a substrate wrapper that includes two or more layers having the same length.

[0194] The substrate wrapper may be a paper wrapper or a non-paper wrapper. Suitable non-paper wrappers include, but are not limited to, sheets of homogenized tobacco material.

[0195] The substrate wrapper may include a laminated sheet. The substrate wrapper may be made of a single laminated sheet. The laminated sheet may be a laminate of a paper layer and an aluminum layer.

[0196] The wrapper may be formed from a laminated material including multiple layers. The wrapper may be formed from a co-laminated sheet of metal, such as a co-laminated sheet of aluminum. The metal layer of the co-laminated sheet may have a basis weight of 12 grams per square meter to 25 grams per square meter, preferably 15 grams per square meter to 20 grams per square meter. The metal layer of the co-laminated sheet may have a thickness of 2 micrometers to 15 micrometers, preferably 3 micrometers to 12 micrometers, more preferably 5 micrometers to 10 micrometers.

[0197] The substrate wrapper may be a paper wrapper containing PVOH (polyvinyl alcohol) or silicon (or polysiloxane). The addition of PVOH (polyvinyl alcohol) or silicon (or polysiloxane) may improve the grease barrier properties of the wrapper.

[0198] The substrate wrapper can include a flame retardant composition that includes one or more flame retardant compounds. As used herein, the term "flame retardant compound" describes a compound that, when added to or otherwise incorporated into a carrier substrate such as a paper or plastic compound, provides varying degrees of flammability protection to the carrier substrate.

[0199] Numerous suitable flame retardant compounds are known to those skilled in the art. Specifically, several flame retardant compounds and formulations suitable for the treatment of cellulosic materials are known and disclosed and may find use in the manufacture of wrappers for aerosol generating articles according to the present invention.

[0200] The substrate wrapper may be a substrate wrapper system formed from two or more individual substrate wrapper sub-sheets. In that case, the thickness of the substrate wrapper can be obtained by adding the thicknesses of the individual substrate wrapper sub-sheets of the substrate wrapper system. Any of the individual substrate wrapper sub-sheets may not extend beyond the end of the aerosol forming substrate portion in the longitudinal axis direction of the aerosol generating article. Each of the individual substrate wrapper sub-sheets forming the substrate wrapper system may be of the same length in a direction parallel to the longitudinal axis of the aerosol generating article.

[0201] The substrate wrapper can be a substrate wrapper system formed from two or more individual substrate wrapper sub-sheets, each of the two or more individual substrate wrapper sub-sheets at least partially surrounds the aerosol forming substrate portion, none of the two or more individual substrate wrapper sub-sheets extends beyond the end of the aerosol forming substrate portion in the longitudinal axis direction of the aerosol generating article, each of the two or more individual substrate wrapper sub-sheets has a thickness of 50 micrometers or more and a density of 800 kilograms or less per cubic meter, and preferably each of the individual substrate wrapper sub-sheets forming the substrate wrapper system is of the same length in a direction parallel to the longitudinal axis of the aerosol generating article.

[0202] The base wrapper can be a base wrapper system formed from two or more individual base wrapper subsheets. Each of the two or more individual base wrapper subsheets at least partially surrounds an aerosol-forming substrate portion. Each of the two or more individual base wrapper subsheets has the same length in the longitudinal direction of the aerosol-generating article. Each of the two or more individual base wrapper subsheets has a thickness of 50 micrometers or more and a density of 800 kilograms per cubic meter or less.

[0203] The base wrapper can be a base wrapper system formed from two or more individual base wrapper subsheets. Each of the two or more individual base wrapper subsheets at least partially surrounds an aerosol-forming substrate portion. None of the two or more individual base wrapper subsheets extends beyond the end of the aerosol-forming substrate portion in the longitudinal direction of the aerosol-generating article. The total of the two or more individual base wrapper subsheets has a thickness of 50 micrometers or more and a density of 800 kilograms per cubic meter or less. Preferably, each of the individual base wrapper subsheets forming the base wrapper system has the same length in a direction parallel to the longitudinal axis of the aerosol-generating article.

[0204] The base wrapper can be a base wrapper system formed from two or more individual base wrapper subsheets. Each of the two or more individual base wrapper subsheets at least partially surrounds an aerosol-forming substrate portion. Each of the two or more individual base wrapper subsheets has the same length in the longitudinal direction of the aerosol-generating article. The total of the two or more individual base wrapper subsheets has a thickness of 50 micrometers or more and a density of 800 kilograms per cubic meter or less.

[0205] The substrate wrapper system may be formed from two separate sheets. The substrate wrapper system may be formed from a first separate sheet and a second separate sheet. The first individual sheet may be provided by a first wrapper and include a first overlapping region formed by overlapping opposing end portions of the first wrapper. The second individual sheet may be provided by a second wrapper and include a second overlapping region formed by overlapping opposing end portions of the second wrapper. The first overlapping region may be offset from the second overlapping region by at least about 5 percent, preferably at least about 10 percent, more preferably at least about 15 percent, and more preferably about 40 percent to about 60 percent around the aerosol-forming substrate portion. One or both of the first and second individual sheets may be paper wrappers.

[0206] The aerosol-generating article may comprise a downstream section located downstream of the aerosol-forming substrate portion. The downstream section is preferably located immediately downstream of the aerosol-forming substrate portion. The downstream section of the aerosol-generating article preferably extends between the aerosol-forming substrate portion and the downstream end of the aerosol-generating article. The downstream section may comprise one or more elements, each of which is described in more detail within the present disclosure.

[0207] The length of the downstream section may be at least 10 millimeters, or at least 20 millimeters, or at least 25 millimeters, or at least 30 millimeters.

[0208] The length of the downstream section may be less than 70 millimeters, or less than 60 millimeters, or less than 50 millimeters.

[0209] For example, the length of the downstream section may be from 20 millimeters to 70 millimeters, or from 25 millimeters to 60 millimeters, or from 30 millimeters to 50 millimeters.

[0210] The downstream section of the aerosol-generating article according to the present invention preferably includes a hollow tubular cooling element provided downstream of the aerosol-forming substrate portion. The hollow tubular cooling element may advantageously provide an aerosol cooling element for the aerosol-generating article.

[0211] The hollow tubular cooling element may be provided immediately downstream of the aerosol-forming substrate portion. In other words, the hollow tubular cooling element may abut against the downstream end of the aerosol-forming substrate portion. The hollow tubular cooling element may define the upstream end of the downstream section of the aerosol-generating article. The downstream end of the aerosol-generating article may coincide with the downstream end of the downstream section. In some embodiments, the downstream section of the aerosol-generating article comprises a single hollow tubular element. In other words, the downstream section of the aerosol-generating article may comprise only one hollow tubular element. In other embodiments, the downstream section comprises two or more hollow tubular elements as described below.

[0212] As used throughout this disclosure, the term "hollow tubular element" generally means an elongate element that defines a lumen or air flow path along its longitudinal axis. In particular, the term "tubular" is used hereinafter with respect to a tubular element that has a substantially cylindrical cross-section and defines at least one air flow conduit that establishes uninterrupted fluid communication between the upstream end and the downstream end of the tubular element. However, it will of course be possible for alternative shapes (for example alternative cross-sectional shapes) of the tubular element to be possible. The hollow tubular cooling element may be an individual discrete element of the aerosol-generating article having a defined length and thickness.

[0213] In the context of the present invention, the hollow tubular cooling element provides an unobstructed flow channel. This means that the hollow tubular cooling element provides a negligible level of pull - through resistance (RTD). The term "negligible level of RTD" is used to indicate an RTD of less than 1 millimeter of water column per 10 millimeters of the length of the hollow tubular cooling element, preferably less than 0.4 millimeter of water column per 10 millimeters of the length of the hollow tubular cooling element, more preferably less than 0.1 millimeter of water column per 10 millimeters of the length of the hollow tubular cooling element.

[0214] The RTD of the hollow tubular cooling element is preferably 10 millimeters of water column or less, or 5 millimeters of water column or less, or 2.5 millimeters of water column or less, or 2 millimeters of water column or less, or 1 millimeter of water column or less.

[0215] The RTD of the hollow tubular cooling element can be at least 0 millimeters of water column, or at least 0.25 millimeters of water column, or at least 0.5 millimeters of water column, or at least 1 millimeter of water column.

[0216] In the aerosol - generating article according to the present invention, the overall RTD of the article essentially depends on the RTD of the rod and optionally the RTD of downstream and / or upstream elements. This is because the hollow tubular cooling element is substantially empty and thus contributes only negligibly to the overall RTD of the aerosol - generating article.

[0217] Therefore, the flow channel should not include any component that would impede the axial air flow. The flow channel is preferably substantially empty, and particularly preferably empty.

[0218] As described in more detail within the present disclosure, the aerosol-generating article may comprise a ventilation zone at a location along the downstream section. In some embodiments, the aerosol-generating article may comprise a ventilation zone at a location along a hollow tubular cooling element. Such, or any, ventilation zone may extend through the peripheral wall of the hollow tubular cooling element. In this way, fluid communication is established between the flow channel internally defined by the hollow tubular cooling element and the external environment. The ventilation zone is further described within the present disclosure.

[0219] The length of the hollow tubular cooling element may be at least 15 millimeters, or at least 20 millimeters, or at least 25 millimeters. The length of the hollow tubular cooling element may be less than 50 millimeters, or less than 45 millimeters, or less than 40 millimeters. For example, the length of the hollow tubular cooling element may be from 15 millimeters to 50 millimeters, or from 20 millimeters to 45 millimeters, or from 20 millimeters to 40 millimeters, or from 20 millimeters to 30 millimeters, or from 25 millimeters to 40 millimeters.

[0220] A relatively long hollow tubular cooling element provides and defines a relatively long internal cavity within the aerosol-generating article and downstream of the aerosol-forming substrate portion. Providing an empty cavity downstream (preferably, immediately downstream) of the aerosol-forming substrate enhances the nucleation of aerosol particles generated by the substrate. Providing a relatively long cavity maximizes the advantages of such nucleation, thereby improving aerosol formation and cooling.

[0221] The wall thickness of the hollow tubular cooling element may be from 100 micrometers to 2 millimeters, or from 150 micrometers to 1.5 millimeters, or from 200 micrometers to 1.25 millimeters.

[0222] The hollow tubular cooling element preferably has an outer diameter substantially equal to the outer diameter of the aerosol-generating article.

[0223] The hollow tubular cooling element may have an outer diameter of 5 millimeters to 10 millimeters, for example, 5.5 millimeters to 9 millimeters, or 6 millimeters to 8 millimeters. In certain embodiments, the hollow tubular cooling element has an outer diameter of less than 7 millimeters.

[0224] The hollow tubular cooling element may have an inner diameter. Preferably, the hollow tubular cooling element has a constant inner diameter along the length of the hollow tubular cooling element. However, the inner diameter of the hollow tubular cooling element may vary along the length of the hollow tubular cooling element.

[0225] The hollow tubular cooling element may have an inner diameter of at least 2 millimeters. For example, the hollow tubular cooling element may have an inner diameter of at least 3 millimeters, at least 4 millimeters, or at least 5 millimeters.

[0226] By providing a hollow tubular cooling element having an inner diameter as presented above, advantageously, sufficient rigidity and strength can be provided to the hollow tubular cooling element.

[0227] The hollow tubular cooling element may have an inner diameter of 10 millimeters or less. For example, the hollow tubular cooling element may have an inner diameter of 9 millimeters or less, 8 millimeters or less, or 7 millimeters or less.

[0228] The provision of a hollow tubular cooling element having an inner diameter as presented above is advantageously, may reduce the draw resistance of the hollow tubular cooling element.

[0229] The hollow tubular cooling element may have an inner diameter of 2 millimeters to 10 millimeters, 3 millimeters to 9 millimeters, 4 millimeters to 8 millimeters, or 5 millimeters to 7 millimeters.

[0230] The lumen or cavity of the hollow tubular cooling element may have any cross-sectional shape. The lumen of the hollow tubular cooling element may have a circular cross-sectional shape.

[0231] The hollow tubular cooling element may include a paper-based material. The hollow tubular cooling element may include at least one layer of paper. The paper can be very hard paper. The paper can be curled paper such as heat-resistant curled paper or curled sulfuric acid paper.

[0232] Preferably, the hollow tubular cooling element may include cardboard. The hollow tubular cooling element can be a cardboard tube. The hollow tubular cooling element can be formed from cardboard. Advantageously, cardboard provides a balance between being deformable to facilitate insertion of an article into the aerosol generating device and being sufficiently rigid to provide proper engagement of the article with the interior of the device, and is a cost-effective material. Thus, the cardboard tube may provide appropriate resistance to deformation or compression during use.

[0233] The hollow tubular cooling element can be a paper tube. The hollow tubular cooling element can be a tube formed from spirally wound paper. The hollow tubular cooling element can be formed from a plurality of layers of paper. The paper can have a basis weight of at least 50 grams per square meter, at least 60 grams per square meter, at least 70 grams per square meter, or at least 90 grams per square meter.

[0234] The hollow tubular cooling element may include a polymer material. For example, the hollow tubular cooling element may include a polymer film. The polymer film can include a cellulose film. The hollow tubular cooling element can include low density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers. The hollow tube can include cellulose acetate tow.

[0235] When the hollow tubular cooling element includes cellulose acetate tow, the cellulose acetate tow can have 2 to 4 denier per filament and a total denier of 25 to 40.

[0236] Preferably, the aerosol-generating article according to the present invention comprises a ventilation zone at a position along the downstream section. More specifically, in those embodiments where the downstream section comprises a hollow tubular cooling element, the ventilation zone may be provided at a position along the hollow tubular cooling element. Alternatively or additionally, in those embodiments where the downstream section comprises a downstream hollow tubular element, the ventilation zone may be provided at a position along the downstream hollow tubular element.

[0237] Accordingly, the ventilated cavity is provided downstream of the aerosol-forming substrate portion. This provides several potential technical advantages. First, the inventors have found that one such ventilated hollow tubular cooling element provides particularly efficient cooling of the aerosol. Second, the inventors have surprisingly found that such rapid cooling of the volatile species released upon heating of the aerosol-forming substrate enhances the nucleation of aerosol particles.

[0238] The ventilation zone may typically include a plurality of perforations through the circumferential wall of the hollow tubular cooling element. The ventilation zone preferably includes at least one circumferential row of perforations. In some embodiments, the ventilation zone may include two circumferential rows of perforations. For example, the perforations may be formed online during the manufacture of the aerosol-generating article. Preferably, each circumferential row of perforations includes from 8 to 30 perforations.

[0239] The aerosol-generating article according to the present invention may have a ventilation level of at least 40 percent. By increasing the ventilation level, the level of aerosol cooling may be increased. However, increasing the ventilation level may mean that less air enters the aerosol-generating article through the upstream end thereof and then flows through the aerosol-forming substrate portion. Accordingly, the ventilation level may be selected based on the desired temperature and composition of the aerosol delivered to the user.

[0240] The aerosol-generating article preferably has a ventilation level of at least 45 percent, more preferably at least 50 percent, more preferably at least 60 percent, and more preferably at least 70 percent.

[0241] The aerosol-generating article according to the present invention may have a ventilation level of 90 percent or less, more preferably 85 percent or less, and more preferably 80 percent or less.

[0242] Therefore, the aerosol-generating article according to the present invention may have a ventilation level of from 45 percent to 90 percent, more preferably from 45 percent to 85 percent, and even more preferably from 45 percent to 80 percent. The aerosol-generating article according to the present invention may have a ventilation level of from 50 percent to 90 percent, preferably from 50 percent to 85 percent, and more preferably from 50 percent to 80 percent. The aerosol-generating article according to the present invention may have a ventilation level of from 60 percent to 90 percent, preferably from 60 percent to 85 percent, and more preferably from 60 percent to 80 percent. The aerosol-generating article according to the present invention may have a ventilation level of from 70 percent to 90 percent, preferably from 70 percent to 85 percent, and more preferably from 70 percent to 80 percent.

[0243] For example, the aerosol-generating article may have a ventilation level of about 75 percent.

[0244] As discussed in the present disclosure, the downstream section may comprise a downstream filter segment. The downstream filter segment may extend to the downstream end of the downstream section. The downstream filter segment may be located at the downstream end of the aerosol-generating article. The downstream end of the downstream filter segment may define the downstream end of the aerosol-generating article. The downstream filter segment may also be referred to as the mouth-side end filter.

[0245] The downstream filter segment may be located downstream of the hollow tubular cooling element, as described above. The downstream filter segment may extend between the hollow tubular cooling element and the downstream end of the aerosol-generating article.

[0246] The downstream filter segment is preferably a solid plug, which may also be described as a "plain" plug and is non-tubular. Thus, the filter segment preferably has a substantially uniform cross-section.

[0247] The downstream filter segment is preferably formed of a fibrous filter material. The fibrous filter material may be for filtering the aerosol generated from the aerosol-forming substrate. Suitable fibrous filter materials will be known to those skilled in the art. Particularly preferably, at least one downstream filter segment comprises a cellulose acetate filter segment formed from cellulose acetate tow.

[0248] In certain preferred embodiments, the downstream section comprises a single downstream filter segment. In alternative embodiments, the downstream section comprises two or more downstream filter segments axially aligned in an end-to-end abutting relationship with each other.

[0249] The downstream filter segment may optionally include a flavorant provided in any suitable form. For example, the downstream filter segment may comprise one or more capsules, beads, or granules of flavorant, or a thread or filament filled with one or more flavors.

[0250] The downstream filter segment preferably has a low particle filtration efficiency.

[0251] The downstream filter segment is preferably surrounded by a plug wrap. The downstream filter segment is preferably non-vented so that air does not enter the aerosol-generating article along the downstream filter segment.

[0252] The downstream filter segment is preferably connected by a tipping wrapper to one or more of the adjacent upstream components of the aerosol-generating article.

[0253] The downstream filter segment preferably has an outer diameter that is approximately equal to the outer diameter of the aerosol-generating article. The outer diameter of the downstream filter segment may be substantially the same as the outer diameter of the hollow tubular cooling element.

[0254] The outer diameter of the downstream filter segment can be 5 millimeters to 10 millimeters, or 5.5 millimeters to 9 millimeters, or 6 millimeters to 8 millimeters. In certain embodiments, the outer diameter of the downstream filter segment is less than 7 millimeters.

[0255] Unless otherwise specified, the draw resistance (RTD) of a component or aerosol-generating article is measured in accordance with ISO6565-2015. The RTD refers to the pressure required to force air through the entire length of the component. The terms "pressure drop" or "draw resistance" of a component or article can also refer to "resistance to draw". Such terms generally refer to measurements in accordance with ISO6565-2015, which are normally carried out at a temperature of 22 degrees Celsius, a pressure of 101 kPa (about 760 Torr), and a relative humidity of 60%, with a volumetric flow rate of 17.5 milliliters per second at the output or downstream end of the component being measured. The conditions for smoking and the specifications of the smoking machine are presented in ISO standard 3308 (ISO3308:2000). The atmosphere for conditioning and testing is presented in ISO standard 3402 (ISO3402:1999).

[0256] The draw resistance (RTD) can be expressed in the pressure unit "millimeters of water column" (mmWG).

[0257] The drawdown resistance (RTD) of the downstream section may be at least 0 millimeter of water column. The RTD of the downstream section may be at least 3 millimeters of water column. The RTD of the downstream section may be at least 6 millimeters of water column. The RTD of the downstream section may be 12 millimeters of water column or less. The RTD of the downstream section may be 11 millimeters of water column or less. The RTD of the downstream section may be 10 millimeters of water column or less.

[0258] The drawdown resistance (RTD) characteristics of the downstream section may be entirely or mostly due to the RTD characteristics of the downstream filter segment of the downstream section. In other words, the RTD of the downstream filter segment of the downstream section may completely define the RTD of the downstream section.

[0259] The drawdown resistance (RTD) of the downstream filter segment may be at least 0 millimeter of water column, or at least 3 millimeters of water column, or at least 6 millimeters of water column. The RTD of the downstream filter segment may be 12 millimeters of water column or less, or 11 millimeters of water column or less, or 10 millimeters of water column or less.

[0260] As described above, the downstream filter segment may be formed of a fibrous material. The downstream filter segment may be formed of a porous material. The downstream filter segment may be formed of a biodegradable material. The downstream filter segment may be formed of a cellulose material such as cellulose acetate. For example, the downstream filter segment may be formed from a bundle of cellulose acetate fibers having 10 to 15 denier per filament. For example, the downstream filter segment may be formed from a relatively low density cellulose acetate tow such as a cellulose acetate tow containing fibers of 12 denier per filament.

[0261] The downstream filter segment can be formed of a polylactic acid-based material. The downstream filter segment can be formed of a bioplastic material, preferably a starch-based bioplastic material. The downstream filter segment can be produced by injection molding or extrusion molding. The bioplastic-based material is advantageous because it can provide a downstream filter segment structure that is simple and inexpensive to manufacture with a specific complex cross-sectional profile that includes a plurality of relatively large air flow channels extending through the downstream filter segment material that provide suitable RTD characteristics.

[0262] The length of the downstream filter segment can be at least 5 millimeters, or at least 10 millimeters. The length of the downstream filter segment can be less than 25 millimeters, or less than 20 millimeters. For example, the length of the downstream filter segment can be 5 millimeters to 25 millimeters, or 10 millimeters to 25 millimeters, or 5 millimeters to 20 millimeters, or 10 millimeters to 20 millimeters.

[0263] The downstream section may further comprise one or more additional hollow tubular elements.

[0264] In certain embodiments, the downstream section may comprise a hollow tubular support element upstream of the hollow tubular cooling element described above. Preferably, the hollow tubular support element abuts the downstream end of the aerosol-forming substrate portion. Preferably, the hollow tubular support element abuts the upstream end of the hollow tubular cooling element. The hollow tubular support element and the hollow tubular cooling element are preferably adjacent to each other and together provide a hollow tubular section within the downstream section.

[0265] The hollow tubular 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, crumpled paper (such as crumpled heat-resistant paper or crumpled sulfuric acid paper), and polymeric materials (such as low-density polyethylene (LDPE)). In a preferred embodiment, the support element is formed from cellulose acetate. Other suitable materials include polyhydroxyalkanoate (PHA) fibers. In a preferred embodiment, the hollow tubular support element comprises a hollow acetate tube.

[0266] The hollow tubular support element preferably has an outer diameter that is approximately equal to the outer diameter of the aerosol-generating article.

[0267] The hollow tubular support element may have an outer diameter of from 5 millimeters to 10 millimeters, such as from 5.5 millimeters to 9 millimeters, or from 6 millimeters to 8 millimeters. In a preferred embodiment, the hollow tubular support element has an outer diameter of less than 7 millimeters.

[0268] The hollow tubular support element may have a wall thickness of at least 1 millimeter, preferably at least 1.5 millimeters, more preferably at least 2 millimeters.

[0269] The hollow tubular support element may have a length of at least 5 millimeters. Preferably, the support element has a length of at least 6 millimeters, more preferably at least 7 millimeters.

[0270] The hollow tubular support element may have a length of less than 15 millimeters. Preferably, the hollow tubular support element has a length of less than 12 millimeters, more preferably less than 10 millimeters.

[0271] In some embodiments, the hollow tubular support element has a length of from 5 millimeters to 15 millimeters, preferably from 6 millimeters to 15 millimeters, more preferably from 7 millimeters to 15 millimeters. In other embodiments, the hollow tubular support element has a length of from 5 millimeters to 12 millimeters, preferably from 6 millimeters to 12 millimeters, more preferably from 7 millimeters to 12 millimeters. In further embodiments, the support element has a length of from 5 millimeters to 10 millimeters, preferably from 6 millimeters to 10 millimeters, more preferably from 7 millimeters to 10 millimeters.

[0272] As an alternative to, or in addition to, the hollow tubular support element, the downstream section may further comprise a downstream hollow tubular element downstream of the hollow tubular cooling element. The downstream hollow tubular element may be provided immediately adjacent to the hollow tubular cooling element. Alternatively and preferably, the downstream hollow tubular element is separated from the hollow tubular cooling element by at least one other component. For example, the downstream section may comprise a downstream filter segment between the hollow tubular cooling element and the downstream hollow tubular element.

[0273] The downstream hollow tubular element preferably extends to the downstream end of the downstream section. Thus, the downstream hollow tubular element preferably extends to the downstream end of the aerosol-generating article. When the downstream hollow tubular element extends to the downstream end of the aerosol-generating article, the downstream hollow tubular element may define the mouth-side end cavity of the aerosol-generating article.

[0274] In certain embodiments, an additional downstream hollow tubular element may be provided such that the downstream section comprises two adjacent downstream hollow tubular elements downstream of the downstream filter segment.

[0275] The RTD of the downstream hollow tubular element may be 10 millimeters of water column or less, or 5 millimeters of water column or less, or 2.5 millimeters of water column or less, or 2 millimeters of water column or less. The RTD of the downstream hollow tubular element is preferably 1 millimeter of water column or less. The RTD of the downstream hollow tubular element may be at least 0 millimeters of water column, or at least 0.25 millimeters of water column, or at least 0.5 millimeters of water column, or at least 1 millimeter of water column.

[0276] Therefore, the air flow channel of the downstream hollow tubular element should not include any component that would impede the flow of air in the long axis direction. The flow channel is preferably substantially empty, and particularly preferably empty.

[0277] Preferably, the length of the downstream hollow tubular element is at least 3 millimeters, more preferably at least 4 millimeters, more preferably at least 5 millimeters, more preferably at least 6 millimeters. The length of the downstream hollow tubular element is preferably less than 20 millimeters, more preferably less than 15 millimeters, more preferably less than 12 millimeters, more preferably less than 10 millimeters.

[0278] The lumen or cavity of the downstream hollow tubular element may have any cross-sectional shape. The lumen of the downstream hollow tubular element may have a circular cross-sectional shape.

[0279] The downstream hollow tubular element may include a paper-based material. The downstream hollow tubular element may include at least one layer of paper. The paper can be very hard paper. The paper can be curled paper such as heat-resistant curled paper or curled sulfuric acid paper. The downstream hollow tubular element may include cardboard. The downstream hollow tubular element can be a cardboard tube.

[0280] The downstream hollow tubular element can be a paper tube. The downstream hollow tubular element can be a tube formed from spirally wound paper. The downstream hollow tubular element can be formed from a plurality of layers of paper. The paper can have a basis weight of at least 50 grams per square meter, at least 60 grams per square meter, at least 70 grams per square meter, or at least 90 grams per square meter.

[0281] The downstream hollow tubular element may contain a polymer material. For example, the downstream hollow tubular element can include a polymer film. The polymer film can include a cellulose film. The downstream hollow tubular element can include low density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers. The downstream hollow tubular element preferably comprises cellulose acetate tow. For example, in a preferred embodiment, the downstream hollow tubular element includes a hollow acetate tube.

[0282] When the downstream hollow tubular element contains cellulose acetate tow, the cellulose acetate tow can have 2 to 4 denier per filament and a total denier of 25 to 40.

[0283] If the downstream section further comprises the additional downstream hollow tubular element described above, the additional downstream hollow tubular element may be formed of the same material or a different material as the downstream hollow tubular element.

[0284] In certain preferred embodiments, the downstream section may comprise a ventilation zone at a location on the downstream hollow tubular element. In one example, this ventilation zone at a location on the downstream hollow tubular element can be provided instead of the ventilation zone at a location on the hollow tubular cooling element. In another example, the ventilation zone at a location on the downstream hollow tubular element can be provided in addition to the ventilation zone provided at a location on the hollow tubular cooling element.

[0285] The ventilation zone at a position along the downstream hollow tubular element may include a plurality of perforations through the peripheral wall of the downstream hollow tubular element. The ventilation zone at a position along the downstream hollow tubular element preferably includes at least one circumferential row of perforations. In some embodiments, the ventilation zone may include two circumferential rows of perforations. For example, the perforations may be formed online during the manufacture of the aerosol generating article. Preferably, each circumferential row of perforations includes 8 to 30 perforations.

[0286] The aerosol generating article may comprise one or more hollow tubular elements. The one or more hollow tubular elements may form part of a downstream section of the aerosol generating article disposed downstream of the aerosol-forming substrate portion. The one or more hollow tubular elements may comprise one or both of a hollow acetate tube (HAT) or a fine hollow acetate tube (FHAT). Such a hollow tube can be made from cellulose acetate and is a cylindrical component provided with an axially disposed central hole. The dimensions of the hollow tube, such as the outer diameter of the hollow tube, the outer diameter of the hole, and the diameter, can vary and can be designed according to the requirements of each product.

[0287] The HAT may have a length of 6 millimeters to 10 millimeters, preferably 7 millimeters to 9 millimeters, more preferably about 8 millimeters. The HAT may be disposed downstream of the aerosol-forming substrate portion, preferably downstream of and in direct contact with the aerosol-forming substrate portion. The HAT may function as one or more of an air flow cooling element and an air flow accelerating element.

[0288] The FHAT may be disposed downstream of the HAT, preferably downstream of and in direct contact with the HAT. The inner diameter of the FHAT may be larger than the inner diameter of the HAT. For example, the inner diameter of the FHAT may be about twice the inner diameter of the HAT. The FHAT may function as an air flow decelerating element.

[0289] The aerosol-generating article may comprise a mouth-end filter. The mouth-end filter may be disposed downstream of the aerosol-forming substrate portion. The mouth-end filter may be disposed at the proximal end of the aerosol-generating article. The mouth-end filter may be disposed downstream of the FHAT and may directly abut the FHAT.

[0290] The mouth-end filter may include a filter material. The filter material may be a filament material, such as cellulose acetate. The denier per filament may be 12. The denier of the filter material may be 12Y28.

[0291] The length of the mouth-end filter along the longitudinal axis of the aerosol-generating article may be 10 millimeters to 14 millimeters, preferably 11 millimeters to 13 millimeters, more preferably about 12 millimeters.

[0292] The draw resistance of the mouth-end filter may be 1 millimeter water column to 100 millimeters water column, preferably 2 millimeters water column to 50 millimeters water column, more preferably 5 millimeters water column to 40 millimeters water column, more preferably 10 millimeters water column to 30 millimeters water column, more preferably 16 millimeters water column to 20 millimeters water column, more preferably 17 millimeters water column to 19 millimeters water column, more preferably about 18 millimeters water column. The draw resistance of the mouth-end filter per millimeter length along the longitudinal axis of the aerosol-generating article may be 0.1 millimeter water column to 20 millimeters water column, preferably 0.2 millimeter water column to 10 millimeters water column, more preferably 0.5 millimeter water column to 5 millimeters water column or more, more preferably 1 millimeter water column to 2 millimeters water column or more, more preferably 1.3 millimeters water column to 1.7 millimeters water column, more preferably 1.4 millimeters water column to 1.6 millimeters water column, more preferably about 1.5 millimeters water column.

[0293] The aerosol-generating article according to the present disclosure further comprises an upstream section located upstream of the aerosol-forming substrate portion. The upstream section is preferably located immediately upstream of the aerosol-forming substrate portion. The upstream section preferably extends between the upstream end of the aerosol-generating article and the aerosol-forming substrate portion. The upstream section includes one or more upstream elements located upstream of the aerosol-forming substrate portion.

[0294] The aerosol-generating article of the present invention preferably comprises an upstream element located upstream of and adjacent to the aerosol-forming substrate portion. The upstream element advantageously prevents direct physical contact with the upstream end of the aerosol-forming substrate portion. Further, the presence of the upstream element helps to prevent any loss of the substrate, which can be advantageous, for example, when the substrate contains particulate plant material.

[0295] If the upstream segment of the aerosol-forming substrate portion includes shredded tobacco, such as tobacco cut filler, the upstream section or its elements may additionally help to prevent loss of loose particles of tobacco from the upstream end of the article. This can be particularly important, for example, when the density of the shredded tobacco is relatively low.

[0296] The upstream element may be a porous plug element. The upstream element preferably has a porosity of at least 50 percent in the longitudinal direction of the aerosol-generating article. More preferably, the upstream element has a porosity of 50 to 90 percent in the longitudinal direction. The porosity of the upstream element in the longitudinal direction is defined by the ratio of the cross-sectional area of the material forming the upstream element to the internal cross-sectional area of the aerosol-generating article at the location of the upstream element.

[0297] The upstream element can be made of a porous material or can include a plurality of openings. This can be achieved, for example, by laser drilling. The plurality of openings are preferably uniformly distributed across the cross-section of the upstream element.

[0298] The porosity or permeability of the upstream element may advantageously be designed to provide an aerosol-generating article having a specific overall draw resistance (RTD) that does not substantially affect the filtration provided by other parts of the article.

[0299] The upstream element may be formed from a material that is impermeable to air. In such embodiments, the aerosol-generating article may be configured such that air flows into the aerosol-forming substrate portion by suitable ventilation means provided within the wrapper.

[0300] In certain preferred embodiments of the present invention, it may be desirable to minimize the RTD of the upstream element. For example, this may apply to articles intended to be inserted into the cavity of an aerosol-generating device such that the aerosol-forming substrate is externally heated, as described herein. In the case of such articles, it is desirable to provide the article with as low an RTD as possible such that most of the RTD experience by the consumer is provided by the aerosol-generating device rather than the article.

[0301] The RTD of the upstream element may be less than 30 millimeters of water column, or less than 20 millimeters of water column, or less than 10 millimeters of water column, or less than 5 millimeters of water column, or less than 2 millimeters of water column. The RTD of the upstream element may be at least 0.1 millimeter of water column, or at least 0.25 millimeter of water column, or at least 0.5 millimeter of water column. The upstream element preferably has an RTD of less than 2 millimeters of water column per millimeter of length, more preferably less than 1.5 millimeters of water column per millimeter of length, more preferably less than 1 millimeter of water column per millimeter of length, more preferably less than 0.5 millimeter of water column per millimeter of length, more preferably less than 0.3 millimeter of water column per millimeter of length, more preferably less than 0.2 millimeter of water column per millimeter of length.

[0302] Preferably, the combined RTD of the upstream section or its upstream element and the aerosol-forming substrate portion is less than 15 millimeters of water column, more preferably less than 12 millimeters of water column, and even more preferably less than 10 millimeters of water column.

[0303] In certain preferred embodiments, the upstream element is formed of a solid cylindrical plug element having a filled cross-section. Such a plug element may be referred to as a "plane" element. The solid plug element may be porous as described above, but does not have a tubular form and thus does not provide a longitudinal flow channel. The solid plug element preferably has a substantially uniform cross-section.

[0304] In other preferred embodiments, the upstream element is formed from a hollow tubular segment that defines a longitudinal cavity providing an unrestricted flow channel. In such embodiments, the upstream element can provide protection to the aerosol-forming substrate as described above, while having a minimal effect on the overall draw resistance (RTD) and filtration characteristics of the article.

[0305] Preferably, the diameter of the longitudinal cavity of the hollow tubular segment forming the upstream element is at least 3 millimeters, more preferably at least 3.5 millimeters, more preferably at least 4 millimeters, and even more preferably at least 4.5 millimeters. Preferably, the diameter of the longitudinal cavity is maximized to minimize the RTD of the upstream section or its upstream element.

[0306] Preferably, the wall thickness of the hollow tubular segment is less than 2 millimeters, more preferably less than 1.5 millimeters, and even more preferably less than 1 millimeter.

[0307] The upstream element of the upstream section may be made of any material suitable for use in an aerosol-generating article. The upstream element may be made of the same material as that used for one of the other components of the aerosol-generating article, such as, for example, a downstream filter segment or a hollow tubular cooling element. Suitable materials for forming the upstream element include filter materials, ceramics, polymeric materials, cellulose acetate, cardboard, zeolites, or aerosol-forming substrates. The upstream element may include a plug of cellulose acetate. The upstream element may comprise a hollow acetate tube or a cardboard tube.

[0308] The upstream element is preferably formed from a heat-resistant material. For example, the upstream element is preferably formed from a material that can withstand a temperature of up to 350 degrees Celsius. This ensures that the upstream element is not adversely affected by the heating means for heating the aerosol-forming substrate.

[0309] The upstream section or its upstream element preferably has an outer diameter that is approximately equal to the outer diameter of the aerosol-generating article. Preferably, the outer diameter of the upstream section or its upstream element is from 5 millimeters to 8 millimeters, more preferably from 5.25 millimeters to 7.5 millimeters, and even more preferably from 5.5 millimeters to 7 millimeters.

[0310] Preferably, the upstream section or the upstream element has a length of from 2 millimeters to 10 millimeters, more preferably from 3 millimeters to 8 millimeters, and even more preferably from 2 millimeters to 6 millimeters. In a particularly preferred embodiment, the upstream section or the upstream element has a length of 5 millimeters.

[0311] The upstream section is preferably surrounded by a wrapper such as a plug wrap. The wrapper surrounding the upstream section is preferably a hard plug wrap, for example, a plug wrap having a basis weight of at least 80 grams per square meter, or at least 100 grams per square meter, or at least 110 grams per square meter. Thereby, structural rigidity is provided to the upstream section.

[0312] The upstream section is preferably connected by an outer wrapper to the aerosol-forming substrate portion and, optionally, at least a part of the downstream section.

[0313] The aerosol-generating article may comprise an upstream section including a front plug. The front plug may be disposed upstream of the aerosol-forming substrate portion and may directly abut the aerosol-forming substrate portion. The front plug may be disposed at the distal end of the aerosol-generating article. The front plug may comprise a filter material. The length of the front plug along the longitudinal axis of the aerosol-generating article may be from 1 millimeter to 10 millimeters, preferably from 3 millimeters to 7 millimeters, more preferably from 4 millimeters to 6 millimeters, and even more preferably about 5 millimeters. The front plug may be in the form of a complete cylinder.

[0314] The ratio of the thickness of the substrate wrapper to the diameter of the front plug may be in the range of 0.007 to 0.03, preferably 0.015 to 0.027, and more preferably 0.022 to 0.024.

[0315] The outer diameter of the front plug may differ from the outer diameter of the substrate wrapper surrounding the aerosol-forming substrate portion by less than 5 percent, preferably less than 3 percent, and more preferably less than 1 percent. Optionally, the outer diameter of the front plug is 7.1 millimeters.

[0316] The front plug can be surrounded by a front plug wrapper. The ratio of the thickness of the front plug wrapper to the thickness of the base wrapper may be 0.7 or less, more preferably 0.5 or less, more preferably 0.3 or less, and even more preferably 0.2 or less.

[0317] It is possible that no part of the front plug is surrounded by the base wrapper.

[0318] The pulling resistance of the front plug may be 1 millimeter of water column to 150 millimeters of water column, preferably 1 millimeter of water column to 50 millimeters of water column, more preferably 1 millimeter of water column to 20 millimeters of water column, and even more preferably 1 millimeter of water column to 10 millimeters of water column. The pulling resistance of the front plug may also be about 10 millimeters of water column or less.

[0319] The front plug can assist in maintaining the cleanliness of the aerosol generating device by capturing the slurry within the consumable. The front plug can prevent the aerosol forming substrate or the heating element from falling from the aerosol generating article.

[0320] The aerosol generating article according to the present invention may have an overall length of at least 40 millimeters, or at least 50 millimeters, or at least 60 millimeters.

[0321] The overall length of the aerosol generating article according to the present invention may also be 90 millimeters or less, or 85 millimeters or less, or 80 millimeters or less.

[0322] In some embodiments, the overall length of the aerosol-generating article is preferably from 50 millimeters to 90 millimeters, more preferably from 60 millimeters to 90 millimeters, and even more preferably from 70 millimeters to 90 millimeters. In other embodiments, the overall length of the aerosol-generating article is preferably from 50 millimeters to 85 millimeters, more preferably from 60 millimeters to 85 millimeters, and even more preferably from 70 millimeters to 85 millimeters. In further embodiments, the overall length of the aerosol-generating article is preferably from 50 millimeters to 80 millimeters, more preferably from 60 millimeters to 80 millimeters, and even more preferably from 70 millimeters to 80 millimeters. In an exemplary embodiment, the overall length of the aerosol-generating article is 75 millimeters.

[0323] In some embodiments, the overall length of the aerosol-generating article is preferably from 40 millimeters to 70 millimeters, more preferably from 45 millimeters to 70 millimeters. In other embodiments, the overall length of the aerosol-generating article is preferably from 40 millimeters to 60 millimeters, more preferably from about 45 millimeters to about 60 millimeters. In further embodiments, the overall length of the aerosol-generating article is preferably from 40 millimeters to 50 millimeters, more preferably from 45 millimeters to 50 millimeters. In an exemplary embodiment, the overall length of the aerosol-generating article is about 45 millimeters.

[0324] Preferably, the aerosol-generating article has an outer diameter of at least about 5 millimeters. More preferably, the aerosol-generating article has an outer diameter of at least 5.25 millimeters. Even more preferably, the aerosol-generating article has an outer diameter of at least 5.5 millimeters.

[0325] Preferably, the aerosol-generating article has an outer diameter of 8 millimeters or less. More preferably, the aerosol-generating article has an outer diameter of 7.5 millimeters or less. Even more preferably, the aerosol-generating article has an outer diameter of 7 millimeters or less.

[0326] The aerosol generating article may have an outer diameter of 5 millimeters to 8 millimeters, or 5 millimeters to 7.5 millimeters, or 5 millimeters to 7 millimeters, or 5.25 millimeters to 8 millimeters, or 5.25 millimeters to 7.5 millimeters, or 5.25 millimeters to 7 millimeters, or 5.5 millimeters to 8 millimeters, or 5.5 millimeters to 7.5 millimeters, or 5.5 millimeters to 7 millimeters.

[0327] The outer diameter of the aerosol generating article may be substantially constant over the entire length of the article. Alternatively, different portions of the aerosol generating article may have different outer diameters.

[0328] The overall RTD of the aerosol generating article is preferably at least 10 millimeters of water column. For example, the overall RTD of the aerosol generating article may be at least 20 millimeters of water column, at least 30 millimeters of water column, at least 35 millimeters of water column, or at least 40 millimeters of water column.

[0329] The overall RTD of the aerosol generating article may be 70 millimeters of water column or less. For example, the overall RTD of the aerosol generating article may be 65 millimeters of water column or less, 60 millimeters of water column or less, or 55 millimeters of water column or less, or 50 millimeters of water column or less.

[0330] The overall RTD of the aerosol generating article may be 10 millimeters of water column to 70 millimeters of water column. For example, the overall RTD of the aerosol generating article may be 20 millimeters of water column to 65 millimeters of water column, 30 millimeters of water column to 60 millimeters of water column, 35 millimeters of water column to 55 millimeters of water column, or 40 millimeters of water column to 50 millimeters of water column.

[0331] In a particularly preferred embodiment, one or more of the components of the aerosol generating article are individually surrounded by their own wrapper.

[0332] In one embodiment, the aerosol-forming substrate portion and the mouthpiece element are individually packaged. The upstream element, the aerosol-forming substrate portion, and its surrounding substrate wrapper and hollow tubular element are then combined with the outer wrapper. Thereafter, they are combined with a downstream filter element having its own wrapper by tipping paper.

[0333] Preferably, at least one of the components of the aerosol-generating article is wrapped in a hydrophobic wrapper.

[0334] The term "hydrophobic" refers to a surface that exhibits water-repellent properties. One useful way to determine this is to measure the water contact angle. The "water contact angle" is the angle conventionally measured through a liquid, where the liquid / vapor interface meets the solid surface. This quantifies the wettability of the solid surface by the liquid via Young's equation. The hydrophobicity or water contact angle may be determined by utilizing the TAPPI T558 test method, and the results are expressed as the interfacial contact angle and reported in "degrees", which can range from approximately zero to approximately 180 degrees.

[0335] In a preferred embodiment, the hydrophobic wrapper comprises a paper layer having a water contact angle of about 30 degrees or more, preferably about 35 degrees or more, or about 40 degrees or more, or about 45 degrees or more.

[0336] By way of example, the paper layer may contain PVOH (polyvinyl alcohol) or silicon. The PVOH may be applied to the paper layer as a surface coating, or the paper layer may include a surface treatment containing PVOH or silicon.

[0337] The aerosol-generating article may comprise a tipping wrapper that at least partially surrounds the aerosol-forming substrate portion and at least partially surrounds one or more portions of the aerosol-generating article adjacent to the aerosol-forming substrate portion. The one or more adjacent portions may include a front plug.

[0338] The tipping wrapper can be a conventional cigarette paper. The tipping wrapper can have a basis weight of less than 50 grams per square meter. The tipping wrapper may have a thickness of less than 70 micrometers or less than 50 micrometers. The tipping wrapper can have a thickness of about 65 micrometers and a basis weight of about 45 grams per square meter.

[0339] The tipping wrapper can be thinner than the substrate wrapper. The ratio of the thickness of the tipping wrapper to the thickness of the substrate wrapper can be 0.7 or less, more preferably 0.5 or less, more preferably 0.3 or less, more preferably 0.2 or less.

[0340] The aerosol generating article can be provided with ventilation holes. The ventilation holes can promote the nucleation of the aerosol. The ventilation holes can assist in cooling the air flow. The ventilation holes can be provided within the FHAT. The FHAT can be provided with 11 ventilation holes each having a diameter of 0.11 millimeters.

[0341] The total draw resistance of the aerosol generating article can be 5 water column millimeters to 200 water column millimeters, preferably 10 water column millimeters to 150 water column millimeters, more preferably 20 water column millimeters to 100 water column millimeters, more preferably 80 water column millimeters to 80 water column millimeters, more preferably 40 water column millimeters to 60 water column millimeters, more preferably 45 water column millimeters to 55 water column millimeters, more preferably about 48 water column millimeters.

[0342] The aerosol generating article may have a cylindrical shape. The aerosol forming substrate portion may have a cylindrical shape.

[0343] An aerosol-generating article may comprise, in order from the proximal end to the distal end of the article, a mouthpiece filter, one or more intermediate elements, an aerosol-forming substrate portion, and optionally a front plug. The one or more intermediate elements may include one or more of a HAT, a FHAT, and a PLA plug. The overall length of the article may be about 45 millimeters and the length of the aerosol-forming substrate portion may be about 11 millimeters. A tipping wrapper may surround only the complete article or only a portion thereof.

[0344] The aerosol-forming substrate portion may include a susceptor. The susceptor may be at least partially surrounded by the aerosol-forming substrate. The susceptor may be completely surrounded by the aerosol-forming substrate. The susceptor may extend along substantially the entire length of the aerosol-forming substrate portion. Thereby, when the susceptor is heated, an optimized heat distribution within the aerosol-forming substrate may be provided. The susceptor may comprise a flat planar portion. The susceptor may be a flat planar susceptor strip. The susceptor may include a metal or an alloy. The susceptor may include aluminum.

[0345] As used herein, the term "flat planar" relates to a substantially cubic shape having a height that is significantly smaller than the width and the length. For example, the width and the length may each be at least twice the height of the cube. The height of the flat planar cube may also be referred to as the thickness of the susceptor, or the thickness of the flat planar portion of the susceptor.

[0346] Susceptor elements may generally have a thickness in the range of from 0.01 millimeters to 2 millimeters, such as from 0.5 millimeters to 2 millimeters. In some embodiments, the susceptor element preferably has a thickness in the range of from 10 micrometers to 500 micrometers, more preferably from 10 micrometers to 100 micrometers.

[0347] The susceptor may have a thickness of about 35 micrometers to about 85 micrometers. The susceptor may have a thickness of about 45 micrometers to about 75 micrometers. The susceptor may have a thickness of about 55 micrometers to about 65 micrometers.

[0348] The susceptor may be an elongated susceptor disposed substantially in the longitudinal direction within the aerosol-forming substrate portion.

[0349] When used to describe the susceptor, the term "elongated" means that the susceptor has a length dimension that is greater than its width dimension or its thickness dimension, for example, greater than twice its width dimension or its thickness dimension.

[0350] The susceptor may be disposed substantially in the longitudinal direction within the aerosol-forming substrate portion. This means that the length dimension of the elongated susceptor is disposed substantially parallel to the longitudinal axis of the aerosol-forming substrate, for example, within ±10 degrees parallel to the longitudinal axis of the aerosol-forming substrate. The elongated susceptor may be positioned at the radial center position within the aerosol-forming substrate portion and may extend along the longitudinal axis of the aerosol-forming substrate portion.

[0351] The susceptor may be in the form of a pin, rod, strip, or blade.

[0352] The susceptor may have a length of about 5 millimeters to about 15 millimeters, for example, about 6 millimeters to about 12 millimeters, more preferably about 8 millimeters to about 10 millimeters. The susceptor may have a length of about 11 millimeters.

[0353] The susceptor may have a width of at least about 1 millimeter, more preferably at least about 2 millimeters. Typically, the susceptor may have a width of up to 8 millimeters, preferably about 6 millimeters or less.

[0354] The elongated susceptor element preferably has a length that is the same as or shorter than the length of the aerosol-forming substrate portion in which it is incorporated. The length of the susceptor element can be 99% or less, 95% or less, 90% or less, 85% or less, 80% or less, 70% or less, 60% or less, 50% or less of the length of the aerosol-forming substrate portion in which it is incorporated. The length of the susceptor element can be 70% to 99%, preferably 75% to 95%, more preferably 80% to 95%, more preferably 85% to 95% of the length of the aerosol-forming substrate portion in which it is incorporated.

[0355] When the susceptor has a constant cross-section, for example, a circular cross-section, it can have a width or diameter of from about 1 millimeter to about 5 millimeters.

[0356] When the susceptor is in the form of a strip or blade, the strip or blade can have a rectangular cross-section, preferably having a width of from about 2 millimeters to about 8 millimeters, more preferably from about 3 millimeters to about 6 millimeters. The susceptor in the form of a strip or blade can have a width of about 4 millimeters.

[0357] The elongated susceptor can have a thickness of from about 57 micrometers to about 63 micrometers. Even more preferably, the elongated susceptor can have a thickness of from about 58 micrometers to about 62 micrometers. Most preferably, the elongated susceptor has a thickness of about 60 micrometers.

[0358] The draw resistance of the aerosol-forming substrate portion is from 0.1 millimeter of water column to 200 millimeters of water column, preferably from 1 millimeter of water column to 100 millimeters of water column, more preferably from 5 millimeters of water column to 40 millimeters of water column, more preferably from 10 millimeters of water column to 30 millimeters of water column, more preferably from 17 millimeters of water column to 29 millimeters of water column, preferably from 20 millimeters of water column to 26 millimeters of water column, and more preferably about 23 millimeters of water column. The draw resistance of the aerosol-forming substrate portion can be 18 millimeters of water column or more. The draw resistance of the aerosol-forming substrate portion can be 23 millimeters of water column or more.

[0359] Having a low draw resistance of the aerosol-forming substrate portion, for example, less than 10 millimeters of water column, may mean that the interaction between the air flow and the aerosol-forming substrate is slight, such that aerosolization is slight. Having a high draw resistance of the aerosol-forming substrate portion, for example, more than 30 millimeters of water column, may mean that the aerosol-forming substrate portion has a substantial influence on the overall draw resistance of the aerosol-generating article. The draw resistance of the aerosol-forming substrate portion can vary to some extent from article to article due to manufacturing tolerances. By reducing the influence of the aerosol-forming substrate portion on the overall draw resistance of the aerosol-generating article, the draw resistance between different articles can be made more consistent.

[0360] The draw resistance of the aerosol-forming substrate portion per millimeter length of the aerosol-forming substrate portion is from 0.1 millimeter of water column to 20 millimeters of water column, preferably from 0.2 millimeter of water column to 10 millimeters of water column, more preferably from 1 millimeter of water column to 5 millimeters of water column, more preferably from 1.7 millimeters of water column to 2.5 millimeters of water column, and more preferably from 1.9 millimeters of water column to 2.3 millimeters of water column. The draw resistance of the aerosol-forming substrate portion per millimeter length along the long axis direction of the aerosol-generating article can be about 2.1 millimeters of water column.

[0361] The total length of the aerosol-forming substrate portion can be from 1 millimeter to 30 millimeters, preferably from 5 millimeters to 16 millimeters, more preferably from 9 millimeters to 13 millimeters, even more preferably from 10 millimeters to 12 millimeters, along the long-axis direction axis of the aerosol-generating article. The total length of the aerosol-forming substrate portion can be 11 millimeters or less along the direction along the long-axis direction axis of the aerosol-generating article.

[0362] The total length of the aerosol-generating article can be from 10 millimeters to 150 millimeters, preferably from 20 millimeters to 1000 millimeters, more preferably from 30 millimeters to 80 millimeters, even more preferably from 40 millimeters to 50 millimeters, even more preferably from 43 millimeters to 47 millimeters, even more preferably about 45 millimeters. The length of the aerosol-forming substrate along the long-axis direction of the article can be from 22% to 26% of the total length of the aerosol-generating article, preferably about 24% of the total length of the aerosol-generating article.

[0363] The ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article may be at least 0.20. Preferably, the ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article is at least 0.25. More preferably, the ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article is at least 0.30.

[0364] The ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article is preferably 0.60 or less. The ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article is preferably 0.55 or less. More preferably, the ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article is 0.50 or less.

[0365] In some embodiments, the ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article is from 0.20 to 0.60, preferably from 0.20 to 0.55, more preferably from 0.20 to 0.50. In other embodiments, the ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article is from 0.25 to 0.60, preferably from 0.25 to 0.55, more preferably from 0.25 to 0.50. In further embodiments, the ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article is from 0.30 to 0.60, preferably from 0.30 to 0.55, more preferably from 0.30 to 0.50.

[0366] As used herein, the "external diameter" and "outer diameter" of an aerosol-generating article or a component thereof are calculated as the average of a plurality of measurements of the diameter of the aerosol-generating article or a component thereof taken at different positions along the length of the aerosol-generating article or a component thereof.

[0367] Preferably, the aerosol-generating article has an outer diameter of at least about 5 millimeters. More preferably, the aerosol-generating article has an outer diameter of at least 5.25 millimeters. Even more preferably, the aerosol-generating article has an outer diameter of at least 5.5 millimeters.

[0368] Preferably, the aerosol-generating article has an outer diameter of 8 millimeters or less. More preferably, the aerosol-generating article has an outer diameter of 7.5 millimeters or less. Even more preferably, the aerosol-generating article has an outer diameter of 7 millimeters or less.

[0369] Preferably, the aerosol-generating article has a substantially circular cross-section. Preferably, the aerosol-generating article has a substantially uniform cross-section along the entire length of the aerosol-generating article.

[0370] The total density of the aerosol-forming substrate portion can be more than 0.71 milligrams per cubic millimeter. The total density of the aerosol-forming substrate portion may be 0.715 milligrams or more per cubic millimeter. The total density of the aerosol-forming substrate portion may be 0.720 milligrams or more per cubic millimeter. The total density of the aerosol-forming substrate portion may be about 0.725 milligrams per cubic millimeter.

[0371] For example, the substrate wrapper can enclose a cylindrical volume of 6.77 millimeters in diameter and 11 millimeters in length, i.e., a volume of 396 cubic millimeters. The volume can be filled with the aerosol-forming substrate and the susceptor. The total mass of the aerosol-forming substrate in the aerosol-forming substrate portion can be 266 milligrams, and the total mass of the susceptor material in the aerosol-forming substrate portion can be 21.2 milligrams. Then, the total density of the aerosol-forming substrate portion corresponds to 287.2 milligrams divided by 396 cubic millimeters, i.e., 0.725 milligrams per cubic millimeter.

[0372] The total density of the aerosol-generating article at the longitudinal position of the aerosol-forming substrate portion, taking into account the mass and volume of the substrate wrapper and any optional additional wrappers surrounding the substrate wrapper, can be about 0.66 milligrams per cubic millimeter.

[0373] The ratio obtained by dividing the total density of the aerosol-forming substrate portion by the total density of the aerosol-generating article at the longitudinal position of the aerosol-forming substrate portion may be greater than 1.0, preferably greater than 1.05, and more preferably greater than 1.09.

[0374] At least 70% by volume, preferably at least 75% by volume, and more preferably at least about 79% by volume of the internal volume of the aerosol-forming substrate portion can be filled with the aerosol-forming substrate and, optionally, one or more susceptor elements.

[0375] Less than 30% by volume, preferably less than 25% by volume, more preferably about 21% by volume or less of the internal volume of the aerosol-forming substrate portion may be empty.

[0376] The total mass of the aerosol-forming substrate within the aerosol-forming substrate portion may be less than 300 milligrams, preferably less than 290 milligrams. The total mass of the aerosol-forming substrate within the aerosol-forming substrate portion may be about 266 milligrams. The total mass of the aerosol-forming substrate within the aerosol-forming substrate portion may be from 10 milligrams to 3000 milligrams, preferably from 50 milligrams to 1000 milligrams, more preferably from 100 milligrams to 500 milligrams, more preferably from 200 milligrams to 400 milligrams, more preferably from 250 milligrams to 350 milligrams, more preferably from 260 milligrams to 270 milligrams, more preferably from 263 milligrams to 269 milligrams.

[0377] The aerosol-forming substrate portion may comprise an aerosol-forming substrate and a susceptor. The total mass of the susceptor material within the aerosol-forming substrate portion may be from 1 milligram to 100 milligrams, preferably from 5 milligrams to 50 milligrams, more preferably from 10 milligrams to 40 milligrams, more preferably from 15 milligrams to 25 milligrams, more preferably from 20 milligrams to 23 milligrams, more preferably from 20.5 milligrams to 21.7 milligrams.

[0378] The aerosol-forming substrate portion may include an aerosol-forming substrate and a susceptor. The total mass of the susceptor material within the aerosol-forming substrate portion may be from 20.5 milligrams to 21.7 milligrams, and the total mass of the aerosol-forming substrate within the aerosol-forming substrate portion may be from 263 milligrams to 269 milligrams.

[0379] The density of the aerosol-forming substrate may be more than 800 kilograms per cubic meter, preferably more than 825 kilograms per cubic meter, more preferably about 842 kilograms per cubic meter.

[0380] The aerosol-forming substrate may be provided in the form of a sheet. The sheets of the aerosol-forming substrate may be collected upon insertion into the aerosol-forming substrate portion. The density of the sheets of the aerosol-forming substrate may be determined by dividing the basis weight of the sheet by the thickness of the sheet before collecting the sheets.

[0381] The aerosol-forming substrate may be provided in the form of an assembly of sheets of homogenized tobacco material.

[0382] The sheets of homogenized tobacco material may have a basis weight of less than 210 grams per square meter, preferably less than 200 grams per square meter, more preferably about 192 grams per square meter.

[0383] The sheets of homogenized tobacco material may have a thickness of more than 215 micrometers, preferably more than 220 micrometers, more preferably about 228 micrometers.

[0384] The sheets of homogenized tobacco material may be formed sheets. The homogenized tobacco material may contain tobacco particles having an average particle size (D95) of more than 50 micrometers, preferably more than 50 micrometers to less than 100 micrometers, more preferably 60 micrometers to 80 micrometers, more preferably 65 micrometers to 75 micrometers, more preferably about 70 micrometers, prior to the forming process. This tobacco particle size (D95) may result in a rough surface of the sheet. This may result in an increase in the surface area of the sheet. The increased surface may improve aerosolization. This may be particularly advantageous when the total mass of the aerosol-forming substrate within the aerosol-forming substrate portion is reduced. As used herein, the term "average particle size (D95)" is used to indicate the volume-based median of the particle size distribution and is the value of the particle diameter at 95% of the cumulative distribution. The particle size of the particles may be analyzed by laser diffraction.

[0385] The aerosol-forming substrate portion may define a substantially cylindrical shape. The cylindrical shape of the aerosol-forming substrate portion may have a diameter within the range of about 3 millimeters to about 10 millimeters, preferably about 6 millimeters to about 8 millimeters, more preferably about 6.5 millimeters to about 7.5 millimeters, more preferably about 6.6 millimeters to about 7.0 millimeters, more preferably about 6.7 millimeters to about 6.9 millimeters, and even more preferably about 6.75 millimeters to about 6.85 millimeters. The cylindrical shape of the aerosol-forming substrate portion may have a diameter within the range of about 6.8 millimeters to about 7.1 millimeters, or about 6.8 millimeters to about 7.0 millimeters.

[0386] The present invention further relates to a package comprising a plurality of aerosol-generating articles, wherein each aerosol-generating article within the package is the aerosol-generating article described herein.

[0387] The present invention further relates to an aerosol-generating system comprising an aerosol-generating article and an aerosol-generating device as described herein. The aerosol-generating device may comprise a heating chamber configured to receive at least partially the aerosol-generating article therein. The aerosol-generating device may comprise an internal heating element disposed to be inserted into the aerosol-generating article when the aerosol-generating article is at least partially inserted into the heating chamber. The aerosol-generating device may comprise an inductor coil. The inductor coil may at least partially surround the heating chamber. The inductor coil may be disposed to coaxially surround the heating chamber. The inductor coil may be disposed to inductively heat a susceptor element. The susceptor element may be part of the internal heating element of the aerosol-generating device. The susceptor element may be part of the aerosol-generating article. The inductor coil may be disposed to inductively heat the susceptor of the aerosol-generating article when the aerosol-generating article is at least partially inserted into the heating chamber.

[0388] As used herein, the term "aerosol generating article" refers to an article comprising an aerosol forming substrate having the ability to release a volatile compound capable of forming an aerosol. The aerosol generating article may be disposable. An aerosol generating article comprising an aerosol forming substrate that includes tobacco may sometimes be referred to herein as a tobacco stick.

[0389] As used herein, the term "aerosol generating device" refers to a device that interacts with an aerosol forming substrate to generate an aerosol. The aerosol generating device may interact with one or both of an aerosol generating article that includes an aerosol forming substrate and a cartridge that includes an aerosol forming substrate. In some examples, the aerosol generating device may heat the aerosol forming substrate to facilitate release of the volatile compound from the substrate. An electrically operated aerosol generating device may include an atomizer, such as an electric heater, to heat the aerosol forming substrate to form an aerosol.

[0390] As used herein, the term "aerosol generating system" refers to a combination of an aerosol generating device and an aerosol forming substrate thereof. When the aerosol forming substrate forms part of an aerosol generating article, the aerosol generating system refers to the combination of the aerosol generating device and the aerosol generating article. In an aerosol generating system, the aerosol forming substrate and the aerosol generating device cooperate to generate an aerosol.

[0391] The term "tubular element" as used herein is used to mean an elongated element that defines a lumen or air flow passage along its longitudinal axis. Specifically, the term "tubular" is used herein to encompass any tubular element that has a substantially cylindrical cross-section and defines at least one air flow passage that establishes unbroken fluid communication between the upstream end of the tubular element and the downstream end of the tubular element. However, alternative geometric shapes of the tubular element may of course be possible.

[0392] As used herein, the terms "upstream" and "forward," and "downstream" and "rearward" are used to describe the relative positions of components or portions of components of an aerosol-generating article with respect to the direction in which air flows through the aerosol-generating article during use. An aerosol-generating article according to the present invention comprises a proximal end through which an aerosol exits the article during use. The proximal end of the aerosol-generating article may also be referred to as the mouth-side end or the downstream end. The mouth-side end is downstream of the distal end. The distal end of the aerosol-generating article may also be referred to as the upstream end. Components or portions of components of the aerosol-generating article may be described as being upstream or downstream of one another based on their relative positions between the proximal end and the distal end of the aerosol-generating article. The front of a component or portion of a component of the aerosol-generating article is the portion at the end closest to the upstream end of the aerosol-generating article. The rear of a component or portion of a component of the aerosol-generating article is the portion at the end closest to the downstream end of the aerosol-generating article.

[0393] As used herein, the term "longitudinal direction" refers to the direction corresponding to the major longitudinal axis of the aerosol-generating article, which extends between the upstream end and the downstream end of the aerosol-generating article.

[0394] The term "length" means the dimension of a component of the aerosol-generating article in the longitudinal direction. For example, it may be used to mean the dimension of a rod or an elongated tubular element in the longitudinal direction.

[0395] As used herein in connection with the present invention, the term "transverse direction" is used to describe a direction perpendicular to the longitudinal direction. Unless otherwise specified, the "cross-section" of an aerosol-generating article or a component of an aerosol-generating article refers to a cross-section in the transverse direction.

[0396] As used herein, the term "proximal" refers to the user end or the mouth-side end of the aerosol-generating article, and the term "distal" refers to the end opposite the proximal end.

[0397] The components of the aerosol-generating article according to the present invention can be described as being upstream or downstream of each other based on their relative positions between the proximal end and the distal end of the aerosol-generating article.

[0398] The aerosol-generating article may comprise one or more susceptor elements. The one or more susceptor elements may be included within the aerosol-forming substrate portion. For example, the one or more elongate susceptor elements may be disposed substantially longitudinally within the aerosol-forming substrate portion and may be in thermal contact with the aerosol-forming substrate.

[0399] As used herein, the term "susceptor" or "susceptor element" means an element that heats when subjected to an alternating magnetic field. This may be the result of eddy currents induced within the susceptor element, hysteresis losses, or both eddy currents and hysteresis losses. In use, the susceptor element is positioned in thermal contact with, or in close thermal proximity to, the aerosol-forming substrate received within the aerosol-generating device or cartridge. In this way, the aerosol-forming substrate is heated by the susceptor, thereby forming an aerosol.

[0400] The susceptor element can be formed from any material capable of inductively heating the aerosol-forming substrate to a temperature sufficient to generate an aerosol therefrom. Preferred susceptor elements include metal or carbon.

[0401] Preferred susceptor elements may include, or consist of, ferromagnetic materials such as, for example, ferromagnetic alloys, ferrite iron, or ferromagnetic steels, or stainless steels. Suitable susceptor elements may be, or include, aluminum.

[0402] A suitable susceptor element may comprise a non-metallic core with a metal layer, such as a metal strip formed on the surface of a ceramic core. The susceptor element may have a protective outer layer enclosing the susceptor element, such as a protective ceramic layer or a protective glass layer. The susceptor element may comprise a protective coating formed of glass, ceramic, or an inert metal, formed on top of the core of the susceptor element material.

[0403] The susceptor element may be disposed in thermal contact with an aerosol-forming substrate of an aerosol-forming substrate portion in which the susceptor element is incorporated. Thus, when the temperature of the susceptor element rises, the aerosol-forming substrate is heated and an aerosol is formed. The susceptor element is preferably disposed in physical direct contact with the aerosol-forming substrate, for example, within the aerosol-forming substrate.

[0404] An aerosol-generating device suitable for use with the aerosol-generating articles described herein may comprise a heating chamber for receiving at least a portion of the aerosol-generating article, and a heater for heating the aerosol-forming substrate portion of the aerosol-generating article when the aerosol-generating article is received within the heating chamber.

[0405] The aerosol-generating device has a distal end and a mouth-side end. The aerosol-generating device may comprise a body or a housing. The body or housing of the aerosol-generating device may define a device cavity for removably receiving the aerosol-generating article at the mouth-side end of the device.

[0406] The device cavity may be referred to as the heating chamber of the aerosol-generating device. The device cavity may extend between the distal end and the mouth-side (or proximal) end. The distal end of the device cavity may be a closed end, and the mouth-side (or proximal) end of the device cavity may be an open end. The aerosol-generating article may be inserted into the device cavity or the heating chamber via the open end of the device cavity. The device cavity may be cylindrical in shape to conform to the same shape of the aerosol-generating article.

[0407] The expression "received therein" may refer to the fact that a component or element is received, either fully or partially, within another component or element. For example, the expression "the aerosol generating article is received within the device cavity" refers to the aerosol generating article being received, either fully or partially, within the cavity of the aerosol generating device. When the aerosol generating article is received within the device cavity, the aerosol generating article may abut against the distal end of the device cavity. When the aerosol generating article is received within the device cavity, the aerosol generating article may be substantially proximate to the distal end of the device cavity. The distal end of the device cavity may be defined by an end wall.

[0408] The length of the device cavity may be 15 millimeters to 80 millimeters, or 20 millimeters to 70 millimeters, or 25 millimeters to 60 millimeters, or 25 millimeters to 50 millimeters.

[0409] The length of the device cavity (or heating chamber) may be the same as or longer than the length of the aerosol-forming substrate portion. The length of the device cavity may be the same as or longer than the combined length of the upstream section or element and the aerosol-forming substrate portion. When the aerosol generating article is received with the aerosol generating device, the length of the device cavity is preferably such that at least 75 percent of the length of the aerosol-forming substrate portion is inserted or received within the device cavity. When the aerosol generating article is received with the aerosol generating device, the length of the device cavity is more preferably such that at least 80 percent of the length of the aerosol-forming substrate portion is inserted or received within the device cavity. When the aerosol generating article is received with the aerosol generating device, the length of the device cavity is more preferably such that at least 90 percent of the length of the aerosol-forming substrate portion is inserted or received within the device cavity. Thereby, the length of the aerosol-forming substrate portion along which the aerosol-forming substrate can be heated during use is maximized, thereby optimizing the generation of aerosol from the aerosol-forming substrate and reducing tobacco waste.

[0410] The length of the device cavity may be configured such that when the aerosol-generating article is received within the device cavity, a downstream section or a portion thereof protrudes from the device cavity. The length of the device cavity may be such that when the aerosol-generating article is received within the device cavity, a portion of the downstream section (such as a hollow tubular cooling element or a downstream filter segment) protrudes from the device cavity. The length of the device cavity may be such that when the aerosol-generating article is received within the device cavity, a portion of the downstream section (such as a hollow tubular cooling element or a downstream filter segment) is configured to be received within the device cavity.

[0411] At least 25 percent of the length of the downstream section may be inserted or received within the device cavity when the aerosol-generating article is received within the device. At least 30 percent of the length of the downstream section may be inserted or received within the device cavity when the aerosol-generating article is received within the device.

[0412] The diameter of the device cavity may be from 4 millimeters to 10 millimeters. The diameter of the device cavity may be from 5 millimeters to 9 millimeters. The diameter of the device cavity may be from 6 millimeters to 8 millimeters. The diameter of the device cavity may be from 6 millimeters to 7 millimeters.

[0413] The diameter of the device cavity may be substantially the same as or larger than the diameter of the aerosol-generating article. The diameter of the device cavity may be the same as the diameter of the aerosol-generating article to establish a tight fit therewith.

[0414] The device cavity can be configured to establish a tight fit with the aerosol-generating article received within the device cavity. The tight fit can refer to a sliding fit. The aerosol-generating device can comprise a peripheral wall. Such a peripheral wall can define the device cavity or the heating chamber. The peripheral wall defining the device cavity can be configured to engage in a tight fit with the aerosol-generating article received within the device cavity such that there is substantially no gap or empty space between the peripheral wall defining the device cavity and the aerosol-generating article when received within the device.

[0415] Such an airtight fit can establish an airtight fit or configuration between the device cavity and the aerosol-generating article received therein.

[0416] In such an airtight configuration, there will be substantially no gap or empty space between the peripheral wall defining the device cavity and the aerosol-generating article through which air can pass and flow.

[0417] The tight fit with the aerosol-generating article may be established along the entire length of the device cavity or along a portion of the length of the device cavity.

[0418] The aerosol-generating device may comprise an air flow channeling extending between a channel inlet and a channel outlet. The air flow channel can be configured to establish a fluid communication between the interior of the device cavity and the exterior of the aerosol-generating device. The air flow channel of the aerosol-generating device can be defined within the housing of the aerosol-generating device to enable a fluid communication between the interior of the device cavity and the exterior of the aerosol-generating device. When the aerosol-generating article is received within the device cavity, the air flow channel can be configured to provide air flowing into the article to deliver the generated aerosol to the user who sucks from the mouth-side end of the article.

[0419] The airflow channel of the aerosol generating device may be defined within or by the peripheral wall of the housing of the aerosol generating device. In other words, the airflow channel of the aerosol generating device may be defined within the thickness of the peripheral wall, or by the inner surface of the peripheral wall, or by a combination of both. The airflow channel may be partially defined by the inner surface of the peripheral wall and may be partially defined within the thickness of the peripheral wall. The inner surface of the peripheral wall defines the periphery of the device cavity.

[0420] The airflow channel of the aerosol generating device may extend from an inlet located at the mouth-side end or proximal end of the aerosol generating device to an outlet located away from the mouth-side end of the device. The airflow channel may extend along a direction parallel to the longitudinal axis of the aerosol generating device.

[0421] The heater may be any suitable type of heater. In the present invention, the heater is preferably an external heater.

[0422] The heater is preferably located in or around the heating chamber.

[0423] Preferably, when the aerosol generating article is received within the aerosol generating device, the heater externally heats the aerosol-forming substrate portion. Such an external heater may surround the aerosol generating article when inserted or received within the aerosol generating device.

[0424] In some embodiments, the heater is arranged to heat the outer surface of the aerosol-forming substrate portion.

[0425] In some embodiments, the heater is arranged to be inserted into the aerosol-forming substrate when the aerosol-forming substrate is received within the cavity.

[0426] The heater may be disposed within the device cavity or the heating chamber.

[0427] The heater may comprise at least one heating element. The at least one heating element can be any suitable type of heating element. In some embodiments, the device comprises only one heating element. In some embodiments, the device comprises a plurality of heating elements.

[0428] Suitable materials for forming at least one resistive heating element include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (such as molybdenum disilicide), carbon, graphite, metals, metal alloys, and composite materials made of ceramic materials and metal materials. Such composite materials may include doped ceramics or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, and platinum group metals. Examples of suitable metal alloys include stainless steel, nickel-containing, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, and iron-containing alloys, as well as nickel, iron, cobalt, stainless steel-based superalloys, Timetal® (registered trademark), and iron-manganese-aluminum-based alloys.

[0429] In some embodiments, the at least one resistive heating element includes one or more stamped portions of an electrically resistive material (such as stainless steel). Alternatively, the at least one resistive heating element may include a heating wire or filament (such as a Ni-Cr (nickel-chromium), platinum, tungsten, or alloy wire).

[0430] In some embodiments, the at least one heating element includes an electrically insulated substrate, and the at least one resistive heating element is provided on the electrically insulated substrate.

[0431] The electrically insulated substrate can comprise any suitable material. For example, the electrically insulated substrate can comprise one or more of paper, glass, ceramic, anodized metal, coated metal, and polyimide. The ceramic can comprise mica, alumina (Al2O3) or zirconia (ZrO2). Preferably, the electrically insulated substrate has a thermal conductivity of about 40 watts / meter kelvin or less, preferably about 20 watts / meter kelvin or less, and ideally about 2 watts / meter kelvin or less.

[0432] The heater can comprise a heating element comprising a rigid electrically insulated substrate having one or more conductive tracks or wires arranged on its surface. Depending on the size and shape of the electrically insulated substrate, it may be possible to insert the heater directly into the aerosol-forming substrate. If the electrically insulated substrate is not sufficiently rigid, the heating element may include further reinforcement means. Current can pass through one or more conductive tracks to heat the heating element and the aerosol-forming substrate.

[0433] In some embodiments, the heater comprises an induction heating arrangement. The induction heating device can comprise an inductor coil and a power source configured to provide a high-frequency oscillating current to the inductor coil. As used herein, a high-frequency oscillating current means an oscillating current having a frequency of about 500 kHz to about 30 MHz. Advantageously, the heater can comprise a DC / AC inverter for converting a DC current supplied by a DC power source into an alternating current. The inductor coil can be arranged to generate a high-frequency oscillating electromagnetic field when receiving the high-frequency oscillating current from the power source. The inductor coil can be arranged to generate a high-frequency oscillating electromagnetic field within the device cavity. In some embodiments, the inductor coil can substantially surround the device cavity. The inductor coil can extend at least partially along the length of the device cavity.

[0434] The heater may include an induction heating element. The induction heating element may be a susceptor element. The susceptor element may be arranged such that when the aerosol-generating article is received within the cavity of the aerosol-generating device, the oscillating electromagnetic field generated by the inductor coil induces a current within the susceptor element to heat the susceptor element. In these embodiments, it is preferred that the aerosol-generating device is capable of generating an oscillating electromagnetic field having a magnetic field strength (strength of the H field) of from 1 to 5 kiloamperes per meter (kA / m), preferably from 2 to 3 kA / m, for example about 2.5 kA / m. An electrically-operated aerosol-generating device preferably has the ability to generate an oscillating electromagnetic field having a frequency of from 1 to 30 MHz, for example from 1 to 10 MHz, for example from 5 to 7 MHz.

[0435] In these embodiments, the susceptor element is preferably located in contact with the aerosol-forming substrate. In some embodiments, the susceptor element is located within the aerosol-generating device. In these embodiments, the susceptor element may be located within the cavity. The aerosol-generating device may include only one susceptor element. The aerosol-generating device may comprise a plurality of susceptor elements. In some embodiments, the susceptor element is preferably arranged to heat the outer surface of the aerosol-forming substrate.

[0436] The susceptor element may comprise any suitable material as described above in relation to the susceptor element incorporated within the aerosol-forming substrate portion.

[0437] In some embodiments, the aerosol-generating device may comprise at least one resistive heating element and at least one inductive heating element. In some embodiments, the aerosol-generating device may comprise a combination of a resistive heating element and an inductive heating element.

[0438] In use, the heater can be controlled to operate within a defined operating temperature range below the maximum operating temperature. The operating temperature range within the heating chamber (or device cavity) is preferably from about 150 degrees Celsius to about 300 degrees Celsius. The operating temperature range of the heater may be from about 150 degrees Celsius to about 250 degrees Celsius.

[0439] The aerosol generating device may be provided with a power source. The power source may be a DC power source. In some embodiments, the power source is a battery. The power source may be a nickel-metal hydride battery, a nickel-cadmium battery, or a lithium-based battery (e.g., a lithium cobalt, lithium iron phosphate, or lithium polymer battery). However, in some embodiments, the power source may be another form of charge storage device such as a capacitor. The power source may be required to be rechargeable and may have a capacity that allows for sufficient energy storage for one or more user operations, such as one or more experiences of aerosol generation.

[0440] Features described with respect to one embodiment may equally apply to other embodiments of the present invention.

Brief Description of the Drawings

[0441]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0442] [Examples] The following provides a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more of the features of other examples, embodiments, or aspects described herein.

[0443] Example 1: An aerosol generating article, an aerosol forming substrate within an aerosol forming substrate portion, and a substrate wrapper at least partially surrounding the aerosol forming substrate portion. The base wrapper has a thickness of 50 micrometers or more, the base wrapper does not extend in the longitudinal axis direction of the aerosol-generating article beyond the end of the aerosol-forming substrate portion, an aerosol-generating article, wherein the aerosol-forming substrate comprises an aerosol-forming agent content of at least 35% by weight.

[0444] Example 2: An aerosol-generating article, comprising an aerosol-forming substrate within an aerosol-forming substrate portion and a base wrapper at least partially surrounding the aerosol-forming substrate portion, wherein the base wrapper has a thickness of 50 micrometers or more, the base wrapper comprises one or more layers having the same length in the longitudinal axis direction of the aerosol-generating article, and the aerosol-forming substrate comprises an aerosol-forming agent content of at least 35% by weight.

[0445] Example 3: The aerosol-generating article according to Example 2, wherein all combinations of one or more layers of the base wrapper having the same length define a total thickness of the base wrapper of 50 micrometers or more.

[0446] Example 4: The aerosol-generating article according to Example 2 or Example 3, wherein at least one of the one or more layers of the base wrapper has an individual thickness of 50 micrometers or more.

[0447] Example 5: The aerosol-generating article according to Example 4, wherein each of the one or more layers of the base wrapper having the same length has an individual thickness of 50 micrometers or more.

[0448] Example 6: The aerosol-generating article according to any one of Examples 2 to 5, wherein the base wrapper does not extend beyond the longitudinal axis direction ends of the aerosol-forming substrate portion in the longitudinal axis direction of the aerosol-generating article.

[0449] Example 7: The aerosol generating article according to any one of Examples 1 to 6, wherein the base wrapper has a thickness of 60 micrometers or more, preferably 70 micrometers or more, more preferably 75 micrometers or more, more preferably 90 micrometers or more, more preferably 120 micrometers or more, more preferably 145 micrometers or more.

[0450] Example 8: The aerosol generating article according to Example 7, wherein the base wrapper has a thickness of 140 to 160 micrometers.

[0451] Example 9: The aerosol generating article according to any one of Examples 1 to 8, wherein the ratio of the thickness of the base wrapper to the diameter of the aerosol-forming substrate portion is in the range of about 1:120 to about 1:20, or about 1:100 to about 1:30, or about 1:80 to about 1:35, or about 1:60 to about 1:40.

[0452] Example 10: The aerosol generating article according to any one of Examples 1 to 9, wherein the density of the base wrapper is 800 kilograms per cubic meter or less, preferably 750 kilograms per cubic meter or less, more preferably 700 kilograms per cubic meter or less, more preferably 650 kilograms per cubic meter or less, more preferably 600 kilograms per cubic meter or less, more preferably 550 kilograms per cubic meter or less, more preferably 500 kilograms per cubic meter or less, more preferably 450 kilograms per cubic meter or less, more preferably 400 kilograms per cubic meter or less, more preferably 350 kilograms per cubic meter or less, more preferably about 320 kilograms per cubic meter.

[0453] Example 11: The aerosol generating article according to any one of Examples 1 to 10, wherein the base wrapper has a basis weight of less than 60 grams per square meter.

[0454] Example 12: The aerosol generating article according to Example 11, wherein the base wrapper has a basis weight of more than 28 grams per square meter and less than 50 grams per square meter.

[0455] Example 13: The aerosol generating article according to any one of Examples 1 to 12, wherein the base wrapper has a thickness of more than 145 micrometers and a density of 400 kilograms or less per cubic meter.

[0456] Example 14: The aerosol generating article according to any one of Examples 1 to 13, wherein the base wrapper is perforated.

[0457] Example 15: The aerosol generating article according to any one of Examples 1 to 14, wherein the base wrapper is embossed.

[0458] Example 16: The aerosol generating article according to any one of Examples 1 to 13, wherein the base wrapper has a uniform thickness that varies by more than about 30 micrometers, or more than about 20 micrometers, or more than about 10 micrometers, or more than about 5 micrometers at any point.

[0459] Example 17: The aerosol generating article according to any one of Examples 1 to 16, wherein the base wrapper exhibits a wrapper permeability in the range of 4000 cholesteryl units to 4800 cholesteryl units, preferably 4200 cholesteryl units to 4600 cholesteryl units, more preferably 4300 cholesteryl units to 4500 cholesteryl units. The permeability of the cigarette paper is determined by using the international standard test method ISO 2965:2009, and the result is presented as cubic centimeters per minute per square centimeter and is referred to as "cholesteryl unit".

[0460] Example 18: The aerosol generating article according to any one of Examples 1 to 17, wherein the base wrapper has a roughness of about 50 Bekk seconds to about 1000 Bekk seconds, preferably about 100 Bekk seconds to about 200 Bekk seconds.

[0461] Example 19: The aerosol generating article according to any one of Examples 1 to 18, wherein the base wrapper extends along the entire length of the aerosol-forming substrate portion in a direction parallel to the major axis direction of the aerosol generating article.

[0462] Example 20: The aerosol generating article according to any one of Examples 1 to 19, wherein the base wrapper contains one or more of cardboard, plastic, and metal foil.

[0463] Example 21: The aerosol generating article according to any one of Examples 1 to 20, wherein the base wrapper contains one or more of cellulosic materials such as paper, wood, fabric, natural fiber, and artificial fiber.

[0464] Example 22: The aerosol generating article according to any one of Examples 1 to 21, wherein the base wrapper contains a paper layer.

[0465] Example 23: The aerosol generating article according to any one of Examples 1 to 22, wherein the base wrapper contains a laminated sheet, preferably the base wrapper is made of a laminated sheet, and more preferably the laminated sheet is a laminate of a paper layer having an aluminum layer.

[0466] Example 24: The aerosol generating article according to any one of Examples 1 to 23, wherein the base wrapper is formed from a single continuous sheet, preferably a single paper sheet.

[0467] Example 25: The base wrapper is a base wrapper system formed from a first individual wrapper sheet and a second individual wrapper sheet. The first individual wrapper sheet includes a first overlapping region formed by overlapping opposing end portions of the first individual wrapper sheet. The second individual wrapper sheet includes a second overlapping region formed by overlapping opposing end portions of the second individual wrapper sheet. The first overlapping region is offset from the second overlapping region by at least about 5 percent, preferably at least about 10 percent, more preferably at least about 15 percent, more preferably about 40 percent to about 60 percent around the aerosol-forming substrate portion, an aerosol-generating article according to any of Examples 1-23.

[0468] Example 26: An aerosol-generating article according to any of Examples 1-25, wherein the total length of the aerosol-forming substrate portion is 11 millimeters or less.

[0469] Example 27: An aerosol-generating article according to any of Examples 1-26, wherein the aerosol-forming substrate portion defines a substantially cylindrical shape having a diameter in the range of about 6.8 millimeters to about 7.1 millimeters, or about 6.8 millimeters to about 7.0 millimeters.

[0470] Example 28: An aerosol-generating article according to any of Examples 1-27, wherein the aerosol-forming substrate portion comprises a susceptor, and preferably the susceptor is at least partially surrounded by the aerosol-forming substrate.

[0471] Example 29: An aerosol-generating article according to any of Examples 1-28, wherein the total aerosol-forming composition content of the aerosol-forming substrate is at least 40 weight percent, preferably at least 45 weight percent, more preferably at least 50 weight percent, more preferably at least 55 weight percent.

[0472] Example 30: The aerosol-generating article according to any one of Examples 1 to 29, wherein the aerosol-forming substrate comprises nicotine, one or more cellulose-based agents, one or more aerosol-forming substances, and one or more carboxylic acids.

[0473] Example 31: The aerosol-generating article according to Example 30, wherein the one or more carboxylic acids are selected from fumaric acid, maleic acid, and malic acid, preferably the one or more carboxylic acids are selected from fumaric acid and maleic acid, and more preferably the one or more carboxylic acids are fumaric acid.

[0474] Example 32: The aerosol-generating article according to any one of Examples 1 to 31, wherein the aerosol-forming substrate comprises one or more carboxylic acids selected from acetic acid, benzoic acid, lactic acid, and levulinic acid.

[0475] Example 33: The aerosol-generating article according to any one of Examples 1 to 32, wherein the aerosol-forming substrate has a total cellulose-based agent content of 35 wt% to 50 wt%.

[0476] Example 34: The aerosol-generating article according to any one of Examples 1 to 33, wherein the aerosol-forming substrate comprises one or more cellulose-based film-forming agents selected from carboxymethyl cellulose and hydroxypropyl methyl cellulose.

[0477] Example 35: The aerosol-generating article according to any one of Examples 1 to 34, wherein the aerosol-forming substrate comprises one or more cellulose-based reinforcing agents selected from cellulose fibers, microcrystalline cellulose, and cellulose powder.

[0478] Example 36: The aerosol-generating article according to any one of Examples 1 to 35, wherein the aerosol-forming substrate is a solid aerosol-forming film, preferably the solid aerosol-forming film remains solid when heated to a temperature of 180°C to 350°C.

[0479] Example 37: An aerosol generating article according to any one of Examples 1 to 36, wherein the aerosol forming substrate is provided in the form of a gel.

[0480] Example 38: An aerosol generating article according to any one of Examples 1 to 37, wherein the aerosol forming substrate does not contain tobacco.

[0481] Example 39: An aerosol generating system comprising an aerosol generating article according to any one of Examples 1 to 38 and an aerosol generating device comprising a heating chamber configured to at least partially insert the aerosol generating article into the heating chamber.

[0482] Although only by way of illustration, the present invention will be further described with reference to the accompanying drawings.

[0483] FIG. 1a shows an aerosol generating article in cross-section. The aerosol generating article comprises a mouth-end filter 10 located at the proximal end of the article. The article further comprises a PLA (polylactic acid) plug 12, a hollow acetate tube 14, and an aerosol forming substrate portion 16 comprising an aerosol forming substrate. The aerosol forming substrate comprises an aerosol former content of at least 35 weight percent. The mouth-end filter 10, the PLA plug 12, and the hollow acetate tube 14 form a downstream section downstream of the aerosol forming substrate portion 16. The article is surrounded by an outer wrapper 18, such as a tipping wrapper. A central axis 22 extends centrally along the longitudinal axis of the aerosol generating article. The aerosol forming substrate portion 16 is surrounded by a thick substrate wrapper 24. The substrate wrapper 24 does not extend beyond the longitudinal ends of the aerosol forming substrate portion 16 in a direction parallel to the central axis 22.

[0484] Figure 1b shows the aerosol-generating article in cross-section. The article of Figure 1b is identical to the article of Figure 1a, except that the article of Figure 1b further comprises a flat planar susceptor 20. The flat planar susceptor 20 is disposed within the aerosol-forming substrate portion 16 and surrounded by the aerosol-forming substrate.

[0485] Figure 2a shows the aerosol-generating article in cross-section. The article of Figure 2a comprises a mouth-end filter 10, a fine hollow acetate tube 38, a hollow acetate tube 40, an aerosol-forming substrate portion 16 including an aerosol-forming substrate, and a front plug 42. The aerosol-forming substrate comprises an aerosol-forming agent content of at least 35 weight percent. The mouth-end filter 10, the fine hollow acetate tube 38, and the hollow acetate tube 40 form a downstream section downstream of the aerosol-forming substrate portion 16. The front plug 42 forms an upstream section upstream of the aerosol-forming substrate portion 16.

[0486] The aerosol-forming substrate portion 16 may comprise an optional susceptor 20. The front plug 42 may be a filter plug. The distal portion of the article is surrounded by a tipping wrapper 18 and the proximal portion is surrounded by a mouthpiece wrapper 44. A row of circumferential ventilation holes 46 is provided within the region where the mouthpiece wrapper 44 overlaps the tipping wrapper 18. The ventilation holes 46 may be provided in one or both of the fine hollow acetate tube 38, the mouthpiece wrapper 44, and the tipping wrapper 18. The aerosol-forming substrate portion 16 is surrounded by a thick substrate wrapper 24.

[0487] The outer diameter of the article may be about 7 millimeters, preferably 7.1 millimeters. The overall length of the article may be about 45 millimeters. In one embodiment, the length of the mouth-end filter 10 is about 12 millimeters, the length of the fine hollow acetate tube 38 is about 9 millimeters, the length of the hollow acetate tube 40 is about 8 millimeters, the length of the aerosol-forming substrate portion 16 is about 11 millimeters, and the length of the front plug 42 is about 5 millimeters.

[0488] Figure 2b shows the aerosol generating article in cross-section. The aerosol generating article of Figure 2b may have an overall length of about 75 millimeters and an outer diameter of about 6.7 millimeters.

[0489] The article of Figure 2b includes, at the proximal end of the article, a hollow mouthpiece tube 48, for example, a hollow cylindrical tube made of cellulose acetate. The hollow mouthpiece tube 48 defines an internal cavity that extends entirely from the upstream end of the hollow mouthpiece tube 48 to the downstream end of the mouth-side end filter 10. The internal cavity is substantially empty and thus allows for a substantially unrestricted airflow along the internal cavity. The hollow mouthpiece tube 48 does not substantially contribute to the overall RTD of the aerosol generating article. The length of the hollow mouthpiece tube 48 may be about 6 millimeters, and the outer diameter may be about 6.7 millimeters. The wall thickness of the hollow mouthpiece tube 48 may be about 1 millimeter.

[0490] The article further includes a mouth-side end filter 10. The mouth-side end filter 10 may have a length of about 10 millimeters. The outer diameter of the mouth-side end filter 10 may be about 6.7 millimeters.

[0491] The article further includes a hollow tube 50, for example, a cardboard tube. The hollow tube 50 does not substantially contribute to the overall RTD of the aerosol generating article. More specifically, the RTD of the hollow tube 50 is about 0 millimeter water column. The hollow tube 50 may have a length of about 25 millimeters or more, an outer diameter of about 6.7 millimeters, and an inner diameter of about 6.2 millimeters. Thus, the thickness of the peripheral wall of the hollow tube 50 may be about 0.25 millimeters.

[0492] The hollow tube 50 may include one or more rows of ventilation holes 46 circumferentially disposed around the hollow tube 50 in a cross-section substantially perpendicular to the longitudinal axis of the article. The ventilation level of the aerosol generating article may be about 75 percent.

[0493] At the distal end, the article includes an aerosol-forming substrate portion 16 that includes an aerosol-forming substrate. The aerosol-forming substrate includes an aerosol-forming agent content of at least 35 weight percent. The aerosol-forming substrate portion 16 is surrounded by a thick substrate wrapper 24. Further, one or more outer wrappers 18, 44 surrounding at least a portion of the aerosol-generating article may be provided. The one or more outer wrappers 18, 44 also include ventilation holes 46. The outer wrapper 44, when present, may be on a portion of the outer wrapper 18 that is on the hollow tube 50. Thus, the outer wrapper 44 effectively couples the mouth-end filter 10 to the remainder of the components of the article. The width of the outer wrapper 44 may be about 26 millimeters.

[0494] In one embodiment, the aerosol-generating article of FIG. 2b has an overall length of about 80 millimeters and an outer diameter of about 6.5 millimeters, the hollow tube 50 has a length of about 25 millimeters or more, the mouth-end filter 10 has a length of about 10 millimeters, and the length of the hollow mouthpiece tube 48 is about 6 millimeters.

[0495] FIG. 3a shows in cross-section an aerosol-generating article that includes an aerosol-forming substrate portion 16. The aerosol-forming substrate includes an aerosol-forming agent content of at least 35 weight percent. The aerosol-forming substrate portion 16 is surrounded by a thick substrate wrapper 24. The downstream section includes a hollow tube 50 and a mouth-end filter 10. The hollow tube 50 may include one or more rows of ventilation holes 46. The upstream section includes a front plug 42. The front plug 42 may be provided in the form of a cylindrical plug filled with cellulose acetate tow, or may be provided in the form of a hollow cylindrical plug of cellulose acetate tow having a wall thickness of about 1 millimeter. Further, one or more outer wrappers 18, 44 surrounding at least a portion of the aerosol-generating article may be provided.

[0496] The aerosol generating article may have an overall length of about 45 millimeters and an outer diameter of about 7.2 millimeters. The overall length of the downstream section may be about 20 millimeters to 30 millimeters. The length of the mouth-side end filter 10 may be about 7 millimeters. The overall length of the upstream section may be about 5 millimeters.

[0497] Figure 3b shows in cross-section an aerosol generating article comprising an aerosol-forming substrate portion 16 at its distal end. The aerosol-forming substrate comprises at least 35 weight percent aerosol-forming agent content. The aerosol-forming substrate portion 16 is surrounded by a thick-walled substrate wrapper 24. The downstream section comprises a hollow tube 50 and a mouth-side end filter 10. The hollow tube 50 may include one or more rows of ventilation holes 46.

[0498] The aerosol generating article of Figure 3b may have an overall length of about 45 millimeters and an outer diameter of 7.2 millimeters. The hollow tube 50 may have a length of about 20 to 30 millimeters, an outer diameter of about 7.2 millimeters, and an inner diameter of about 6.7 millimeters. Thus, the thickness of the peripheral wall of the hollow tube 50 is about 0.25 millimeters. The mouth-side end filter 10 may have a length of about 5 millimeters to 7 millimeters and an outer diameter of about 7.2 millimeters. The mouth-side end filter 10 may include low-density cellulose acetate filter segments. The RTD of the mouth-side end filter 10 may be about 8 millimeters of water column. The mouth-side end filter 10 may be individually wrapped by a plug wrap (not shown). Further, one or more outer wrappers 18, 44 surrounding at least a portion of the aerosol generating article may be provided.

Claims

1. Aerosol-generating article, Aerosol-forming substrate within the aerosol-forming substrate portion, The aerosol-forming substrate portion comprises a substrate wrapper that at least partially surrounds the aerosol-forming substrate portion, The substrate wrapper has a thickness of 50 micrometers or more. The substrate wrapper does not extend beyond the end of the aerosol-forming substrate portion in the longitudinal direction of the aerosol-generating article. An aerosol generating article wherein the aerosol-forming substrate contains at least 35 weight percent of an aerosol-forming material, and the aerosol-forming substrate contains one or more cellulosic film-forming agents selected from carboxymethylcellulose (CMC), ethylcellulose (EC), hydroxyethylcellulose (HEC), hydroxyethylmethylcellulose (HEMC), hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC), and methylcellulose (MC), and the total cellulosic film-forming agent content is 15 weight percent or more.

2. The aerosol generating article according to claim 1, wherein the substrate wrapper has a thickness of 60 micrometers or more, preferably 100 micrometers or more, more preferably 120 micrometers or more, and more preferably 140 micrometers or more.

3. The aerosol generating article according to claim 2, wherein the substrate wrapper has a thickness of 140 micrometers to 155 micrometers.

4. The aerosol generating article according to claim 1, wherein the ratio of the thickness of the substrate wrapper to the diameter of the aerosol-forming substrate portion is within the range of approximately 1:120 to approximately 1:20, or approximately 1:100 to approximately 1:30, or approximately 1:80 to approximately 1:35, or approximately 1:60 to approximately 1:

40.

5. The aerosol generating article according to claim 1, wherein the total aerosol-forming content of the aerosol-forming substrate is at least 40% by weight, preferably at least 45% by weight, more preferably at least 50% by weight, and more preferably at least 55% by weight.

6. The aerosol generating article according to claim 1, wherein the aerosol-forming substrate comprises nicotine, one or more cellulosic agents, one or more aerosol-forming bodies, and one or more carboxylic acids.

7. The aerosol generating article according to claim 6, wherein the one or more carboxylic acids are selected from fumaric acid, maleic acid, and malic acid, preferably the one or more carboxylic acids are selected from fumaric acid and maleic acid, and more preferably the one or more carboxylic acids are fumaric acid.

8. The aerosol generating article according to claim 1, wherein the aerosol-forming substrate comprises one or more carboxylic acids selected from acetic acid, benzoic acid, lactic acid, and levulinic acid.

9. The aerosol generating article according to claim 1, wherein the aerosol-forming substrate has a total cellulosic agent content of 35% to 50% by weight.

10. The aerosol generating article according to claim 1, wherein one or more cellulosic film-forming agents are selected from carboxymethylcellulose and hydroxypropylmethylcellulose.

11. The aerosol generating article according to claim 1, wherein the aerosol-forming substrate comprises one or more cellulosic reinforcing agents selected from cellulose fibers, microcrystalline cellulose, and cellulose powder.

12. The aerosol generating article according to claim 11, wherein the aerosol-forming substrate has a cellulose-based reinforcing agent content of 5% to 30% by weight on a dry weight basis.

13. The aerosol generating article according to claim 1, wherein the aerosol-forming substrate is a solid aerosol-forming film, and preferably the solid aerosol-forming film remains solid when heated to a temperature of 180°C to 350°C.

14. The aerosol generating article according to claim 1, wherein the aerosol-forming substrate is provided in the form of a gel.

15. The aerosol generating article according to claim 1, wherein the aerosol-forming substrate does not contain tobacco.

16. An aerosol generating system comprising an aerosol generating article according to any one of claims 1 to 15, and an aerosol generating device including a heating chamber configured to at least partially insert the aerosol generating article into the heating chamber.

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