Aerosol-generating article comprising a relatively short rod of aerosol-generating substrate

Abstract

An aerosol-generating article is provided.SOLUTION: The aerosol-generating article comprises a rod of aerosol-generating substrate. The aerosol-generating article has a length of at least 60 millimetres. The rod of aerosol-generating substrate has a length of less than or equal to 36 millimetres. The ratio of the length of the rod of aerosol-generating substrate to the total length of the aerosol-generating article is less than or equal to 0.4.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to an aerosol-generating article that includes an aerosol-generating substrate and is adapted to generate an inhalable aerosol upon heating. [Background technology]

[0002] Aerosol-generating articles in which an aerosol-generating substrate, such as a tobacco-containing substrate, is heated rather than combusted are known in the art. Typically, in such heated smoking articles, an aerosol is generated by transferring heat from a heat source to a physically separate aerosol-generating substrate or material that is in contact with, within, around, or downstream of the heat source. During use of the aerosol-generating article, volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source and are entrained in the air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol.

[0003] Numerous prior art documents disclose aerosol generating devices for consuming aerosol-generating articles. Such devices include, for example, electrically heated aerosol generating devices in which an aerosol is generated by heat transfer from one or more electric heater elements of the aerosol generating device to an aerosol-generating substrate of the heated aerosol-generating article. For example, an electrically heated aerosol generating device has been proposed that includes an internal heater blade adapted to be inserted into the aerosol-generating substrate. The use of an aerosol-generating article in combination with an external heating system is also known. For example, International Publication No. 2020 / 115151 describes the provision of one or more heating elements arranged around the periphery of the aerosol-generating article when the aerosol-generating article is received in a cavity of the aerosol generating device. Alternatively, International Publication No. 2015 / 176898 proposes an inductively heatable aerosol-generating article that includes an aerosol-generating substrate and a susceptor disposed within the aerosol-generating substrate.

[0004] Aerosol-generating articles in which a tobacco-containing substrate is heated rather than combusted present numerous challenges not found in conventional smoking articles. First, the tobacco-containing substrate is typically heated to a significantly lower temperature compared to the temperature reached by the combustion front of a conventional cigarette. This can affect nicotine release from the tobacco-containing substrate and nicotine delivery to the consumer. At the same time, if the heating temperature is increased in an attempt to enhance nicotine delivery, the aerosol generated typically needs to be cooled more extensively and more quickly before reaching the consumer. However, technical solutions commonly used to cool mainstream smoke in conventional smoking articles, such as providing a high-filtration efficiency segment at the mouth end of the cigarette, can have undesirable effects in aerosol-generating articles in which the tobacco-containing substrate is heated rather than combusted, as this can reduce nicotine delivery. As a result, it would be desirable to provide a novel aerosol-generating article that can consistently ensure satisfactory aerosol delivery to the consumer.

[0005] Furthermore, there is a generally felt need for aerosol-generating articles that are easier to use and have improved utility. For example, it would be desirable to provide an aerosol-generating article that can be easily inserted into the heating cavity of an aerosol generating device and at the same time be securely held within the heating cavity so that it does not slip out during use.

[0006] It would be further desirable to provide an aerosol-generating article adapted to more efficiently heat an aerosol-generating substrate when the article is inserted into the heating cavity of an aerosol-generating device, thereby minimizing waste of tobacco material. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2020 / 115151 [Patent Document 2] International Publication No. 2015 / 176898 Summary of the Invention

[0008] The present disclosure relates to an aerosol-generating article. The aerosol-generating article may comprise a rod of an aerosol-generating substrate. The aerosol-generating article may have a length of at least 50 millimeters. The rod of aerosol-generating substrate may have a length of 36 millimeters or less. The ratio of the length of the rod of aerosol-generating substrate to the overall length of the aerosol-generating article may be 0.4 or less.

[0009] The invention will now be further described with reference to the drawings of the accompanying drawings, in which: [Brief explanation of the drawings]

[0010] [Figure 1] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 2] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 3a] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 3b] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 4a] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 4b] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 5] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 6] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 7] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 8] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 9] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 10] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 11] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 12] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 13] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 14] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 15] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present disclosure. [Figure 16] 1 shows a schematic cross-sectional side view of an aerosol generation system including an aerosol generating device and an aerosol-generating article according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] According to the present invention, there is provided an aerosol-generating article comprising a rod of aerosol-generating substrate, the aerosol-generating article having a length of at least 50 millimeters, the rod of aerosol-generating substrate having a length of not more than 36 millimeters, and the ratio of the length of the rod of aerosol-generating substrate to the overall length of the aerosol-generating article being not more than 0.4.

[0012] The present disclosure relates to an aerosol-generating article. The aerosol-generating article may comprise a rod of an aerosol-generating substrate. The aerosol-generating article may have a length of at least 60 millimeters. The rod of aerosol-generating substrate may have a length of 36 millimeters or less. The ratio of the length of the rod of aerosol-generating substrate to the overall length of the aerosol-generating article may be 0.4 or less.

[0013] According to the present invention, there is provided an aerosol-generating article comprising a rod of aerosol-generating substrate, the aerosol-generating article having a length of at least 60 millimeters, the rod of aerosol-generating substrate having a length of not more than 36 millimeters, and the ratio of the length of the rod of aerosol-generating substrate to the overall length of the aerosol-generating article being not more than 0.4.

[0014] The present invention relates to a relatively long aerosol-generating article having a relatively short rod of aerosol-generating substrate. Prior art relatively long aerosol-generating articles have a relatively long rod of aerosol-generating substrate. Therefore, providing a relatively long aerosol-generating article having a relatively short rod of aerosol-generating substrate is a significantly different design from prior art aerosol-generating articles.

[0015] The rod of the aerosol-generating substrate may generate an aerosol upon heating, for example, by an aerosol-generating device. The resulting generated aerosol may be hot and, if delivered to a user immediately after generation, may be very uncomfortable for the user. Therefore, some aerosol-generating articles provide a space for the aerosol to cool after generation and before delivery to the user. In some aerosol-generating articles, the space for cooling is provided between the rod of the aerosol-generating substrate and the downstream end of the aerosol-generating article.

[0016] By shortening the length of the rod of the aerosol-generating substrate while maintaining a relatively long length of the aerosol-generating article, the total length of the path that the generated aerosol must travel within the aerosol-generating article before it is delivered to the user can be increased. By increasing the total length of the path that the aerosol must travel before it is delivered to the user, the aerosol may have more time to cool and decrease in temperature before being delivered to the user.

[0017] Thus, by shortening the rod length of the aerosol-generating substrate while maintaining a relatively long length of the aerosol-generating article, it is possible to provide a cooler aerosol when delivered to the user. A cooler aerosol-generating substrate may improve the overall experience for the user.

[0018] For example, it may be desirable to have a rod of aerosol-generating substrate with a reduced length to maximize the proportion of the rod of aerosol-generating substrate that is heated when the aerosol-generating article is inserted into the heating cavity of an aerosol-generating device. This, in turn, can optimize the efficiency of aerosol generation from the rod of aerosol-generating substrate, thereby minimizing the amount of aerosol-generating substrate possible without affecting aerosol generation. The amount of aerosol-generating substrate that is not used to generate aerosol and is therefore effectively wasted can also be minimized. However, it may also be important to maintain the overall length of the aerosol-generating article so that the article can continue to be used with existing aerosol-generating devices. It may also be important to be able to use existing machinery and packaging without requiring modification.

[0019] The present invention provides a rod of aerosol-generating substrate that is reduced in length while retaining the overall length of the aerosol-generating article.

[0020] An aerosol-generating article according to the present invention comprises a rod of aerosol-generating substrate. Furthermore, the aerosol-generating article according to the present invention comprises one or more elements provided downstream of the aerosol-generating substrate. If present, the one or more elements downstream of the rod of aerosol-generating substrate form the downstream section of the aerosol-generating article. An aerosol-generating article according to the present invention may comprise one or more elements provided upstream of the aerosol-generating substrate. If present, the one or more elements upstream of the rod of aerosol-generating substrate form the upstream section of the aerosol-generating article.

[0021] The rod of aerosol-generating substrate is preferably surrounded by a wrapper such as plug wrap.

[0022] Preferably, the aerosol-generating substrate rod has a length of at least 10 millimeters. Preferably, the aerosol-generating substrate rod has a length of at least 15 millimeters. More preferably, the aerosol-generating substrate rod has a length of at least 17 millimeters. Even more preferably, the aerosol-generating substrate rod has a length of at least 18 millimeters. Most preferably, the aerosol-generating substrate rod has a length of at least 20 millimeters.

[0023] Preferably, the rod of the aerosol-generating substrate has a length of less than 40 millimeters. Preferably, the rod of the aerosol-generating substrate has a length of less than 35 millimeters. More preferably, the rod of the aerosol-generating substrate has a length of less than 30 millimeters.

[0024] For example, the rod of the aerosol-generating substrate preferably has a length of 10 mm to 40 mm, or 10 mm to 35 mm, or 10 mm to 30 mm, or 15 mm to 40 mm, or 15 mm to 35 mm, or 15 mm to 30 mm, or 20 mm to 40 mm, or 20 mm to 35 mm, or 20 mm to 30 mm.

[0025] The rod of the aerosol-generating substrate preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article.

[0026] The "outer diameter of the aerosol-generating substrate rod" may be calculated as the average of multiple measurements of the diameter of the aerosol-generating substrate rod taken at different locations along the length of the aerosol-generating substrate rod.

[0027] Preferably, the aerosol-generating substrate rod has an outer diameter of at least about 5 millimeters. More preferably, the aerosol-generating substrate rod has an outer diameter of at least 5.25 millimeters. Even more preferably, the aerosol-generating substrate rod has an outer diameter of at least 5.5 millimeters.

[0028] Preferably, the aerosol-generating substrate rod has an outer diameter of less than 8 millimeters. More preferably, the aerosol-generating substrate rod has an outer diameter of less than 7.5 millimeters. Even more preferably, the aerosol-generating substrate rod has an outer diameter of less than 7 millimeters.

[0029] It has generally been observed that the smaller the diameter of the aerosol-generating substrate rod, the lower the temperature required to raise the core temperature of the aerosol-generating substrate rod so that a sufficient amount of vaporizable species is released from the aerosol-generating substrate to form a desired amount of aerosol. At the same time, without wishing to be bound by theory, it is understood that the smaller the diameter of the aerosol-generating substrate rod, the faster the heat supplied to the aerosol-generating article can penetrate the entire volume of the aerosol-generating substrate. Nevertheless, if the diameter of the aerosol-generating substrate rod is too small, the volume-to-surface area ratio of the aerosol-generating substrate becomes unfavorable as the amount of available aerosol-generating substrate decreases.

[0030] Aerosol-generating substrate rod diameters within the ranges described herein are particularly advantageous in terms of the balance between energy consumption and aerosol delivery. This advantage is particularly realized when an aerosol-generating article comprising an aerosol-generating substrate rod having the diameters described herein is used in combination with an external heater positioned around the periphery of the aerosol-generating article. Under such operating conditions, it has been observed that less thermal energy is required to achieve a sufficiently high temperature at the core of the aerosol-generating substrate rod, and at the core of the article in general. Therefore, when operating at a lower temperature, the desired target temperature at the core of the aerosol-generating substrate may be achieved within a desirably reduced time frame and with less energy consumption.

[0031] The use of a rod of aerosol-generating substrate having a smaller diameter can also advantageously reduce the overall weight of tobacco material required for the aerosol-generating article while still producing a desired level of aerosol, thus reducing levels of tobacco waste.

[0032] Preferably, the ratio between the length of the aerosol-generating substrate rod and the total length of the aerosol-generating article is at least 0.20. Preferably, the ratio between the length of the aerosol-generating substrate rod and the total length of the aerosol-generating article is at least 0.25. More preferably, the ratio between the length of the aerosol-generating substrate rod and the total length of the aerosol-generating article is at least 0.30.

[0033] Preferably, the ratio between the length of the aerosol-generating substrate rod and the total length of the aerosol-generating article is less than 0.50. Preferably, the ratio between the length of the aerosol-generating substrate rod and the total length of the aerosol-generating article is less than 0.45. More preferably, the ratio between the length of the aerosol-generating substrate rod and the total length of the aerosol-generating article is less than 0.40.

[0034] In some embodiments, the ratio between the length of the rod of the aerosol-generating substrate and the total length of the aerosol-generating article is 0.20 to 0.50, preferably 0.20 to 0.45, and more preferably 0.20 to 0.40. In other embodiments, the ratio between the length of the rod of the aerosol-generating substrate and the total length of the aerosol-generating article is 0.25 to 0.50, preferably 0.25 to 0.45, and more preferably 0.25 to 0.40. In further embodiments, the ratio between the length of the rod of the aerosol-generating substrate and the total length of the aerosol-generating article is 0.30 to 0.50, preferably 0.30 to 0.45, and more preferably 0.30 to 0.40. In yet further embodiments, the ratio between the length of the rod of the aerosol-generating substrate and the total length of the aerosol-generating article is 0.30 to 0.50, preferably 0.30 to 0.45, and more preferably 0.30 to 0.40.

[0035] Preferably, the rod of aerosol-generating substrate has a substantially uniform cross section along the length of the rod, and it is particularly preferred that the rod of aerosol-generating substrate has a substantially circular cross section.

[0036] Preferably, the density of the aerosol-generating substrate is at least 100 mg per cubic centimeter. More preferably, the density of the aerosol-generating substrate is at least 125 mg per cubic centimeter. More preferably, the density of the aerosol-generating substrate is at least 150 mg per cubic centimeter. Even more preferably, the density of the aerosol-generating substrate is at least 200 mg per cubic centimeter.

[0037] Preferably, the density of the aerosol-generating substrate is less than 1000 mg per cubic centimeter. More preferably, the density of the aerosol-generating substrate is less than 800 mg per cubic centimeter. More preferably, the density of the aerosol-generating substrate is less than 700 mg per cubic centimeter. More preferably, the density of the aerosol-generating substrate is less than 600 mg per cubic centimeter. More preferably, the density of the aerosol-generating substrate is less than 500 mg per cubic centimeter. More preferably, the density of the aerosol-generating substrate is less than 400 mg per cubic centimeter. More preferably, the density of the aerosol-generating substrate is less than 350 mg per cubic centimeter. More preferably, the density of the aerosol-generating substrate is less than 345 mg per cubic centimeter. More preferably, the density of the aerosol-generating substrate is less than 325 mg per cubic centimeter. More preferably, the density of the aerosol-generating substrate is less than 300 mg per cubic centimeter. More preferably, the density of the aerosol-generating substrate is less than 290 mg per cubic centimeter. Even more preferably, the density of the aerosol-generating substrate is less than 280 mg per cubic centimeter.

[0038] For example, the density of the aerosol-generating substrate is preferably 100 mg per cubic centimeter to 1000 mg per cubic centimeter, preferably 100 mg per cubic centimeter to 800 mg per cubic centimeter, more preferably 100 mg per cubic centimeter to 700 mg per cubic centimeter, more preferably 100 mg per cubic centimeter to 600 mg per cubic centimeter, more preferably 100 mg per cubic centimeter to 500 mg per cubic centimeter, and even more preferably 100 mg per cubic centimeter to 400 mg per cubic centimeter.

[0039] For example, the density of the aerosol-generating substrate is preferably 100 mg per cubic centimeter to 350 mg per cubic centimeter, preferably 100 mg per cubic centimeter to 345 mg per cubic centimeter, preferably 125 mg per cubic centimeter to 325 mg per cubic centimeter, more preferably 150 mg per cubic centimeter to 300 mg per cubic centimeter, more preferably 150 mg per cubic centimeter to 290 mg per cubic centimeter, and even more preferably 200 mg per cubic centimeter to 280 mg per cubic centimeter.

[0040] The aerosol-generating substrate may comprise tobacco material. The rod of the aerosol-generating substrate may comprise tobacco material. The tobacco material may comprise shredded tobacco material. The shredded tobacco material may be in the form of cut filler or tobacco cut filler.

[0041] Preferably, the tobacco material has a bulk density of at least 100 mg per cubic centimeter. More preferably, the tobacco material has a bulk density of at least 125 mg per cubic centimeter. More preferably, the tobacco material has a bulk density of at least 150 mg per cubic centimeter. Even more preferably, the tobacco material has a bulk density of at least 200 mg per cubic centimeter. Preferably, the tobacco material has a bulk density of less than 345 milligrams per cubic centimeter. More preferably, the tobacco material has a bulk density of less than 325 milligrams per cubic centimeter. Even more preferably, the tobacco material has a bulk density of less than 300 milligrams per cubic centimeter. Even more preferably, the tobacco material has a bulk density of less than 290 milligrams per cubic centimeter. Even more preferably, the tobacco material has a bulk density of less than 280 milligrams per cubic centimeter. For example, the tobacco material may have a bulk density of 100 milligrams per cubic centimeter to 350 milligrams per cubic centimeter, preferably 100 milligrams per cubic centimeter to 345 milligrams per cubic centimeter, more preferably 125 milligrams per cubic centimeter to 325 milligrams per cubic centimeter, more preferably 150 milligrams per cubic centimeter to 300 milligrams per cubic centimeter, more preferably 150 milligrams per cubic centimeter to 290 milligrams per cubic centimeter, and even more preferably 200 milligrams per cubic centimeter to 280 milligrams per cubic centimeter.

[0042] The term "density" as used herein in relation to an aerosol-generating substrate refers to the bulk density of the aerosol-generating substrate, which can be calculated by measuring the total weight of the aerosol-generating substrate and dividing it by the volume of the rod of aerosol-generating substrate (excluding the wrapper).

[0043] The bulk density of the tobacco material in the aerosol-generating substrate can be calculated by dividing the total mass of the tobacco material in the rod of aerosol-generating substrate by the volume of the aerosol-generating substrate (excluding the wrapper). The mass of the tobacco material in the aerosol-generating substrate can be determined by removing the tobacco material from the aerosol-generating substrate and weighing it. The bulk density of the tobacco material in the aerosol-generating substrate can also be determined after conditioning the aerosol-generating substrate in accordance with ISO Standard 3402:1999.

[0044] The aerosol-generating substrate may comprise shredded tobacco material. The rod of the aerosol-generating substrate may comprise shredded tobacco material. The shredded tobacco material may be in the form of cut filler or tobacco cut filler. The density of such an aerosol-generating substrate or shredded tobacco material may be in accordance with the following:

[0045] In certain preferred embodiments, the aerosol-generating substrate rod comprises a cut tobacco material, such as tobacco cut filler, having a density of less than 350 mg per cubic centimeter, preferably less than 345 mg per cubic centimeter, preferably less than 325 mg per cubic centimeter, more preferably less than 300 mg per cubic centimeter, more preferably less than 290 mg per cubic centimeter, and more preferably less than 280 mg per cubic centimeter. Preferably, the aerosol-generating substrate rod comprises a cut tobacco material having a bulk density of at least 100 mg per cubic centimeter. More preferably, the aerosol-generating substrate rod comprises a cut tobacco material having a bulk density of at least 125 mg per cubic centimeter. More preferably, the aerosol-generating substrate rod comprises a cut tobacco material having a bulk density of at least 150 mg per cubic centimeter. Even more preferably, the aerosol-generating substrate rod comprises a cut tobacco material having a bulk density of at least 200 mg per cubic centimeter. For example, a rod of aerosol-generating substrate may comprise cut tobacco material having a density of from 100 mg per cubic centimeter to 350 mg per cubic centimeter, preferably from 100 mg per cubic centimeter to 345 mg per cubic centimeter, preferably from 125 mg per cubic centimeter to 325 mg per cubic centimeter, more preferably from 150 mg per cubic centimeter to 300 mg per cubic centimeter, more preferably from 150 mg per cubic centimeter to 290 mg per cubic centimeter, even more preferably from 200 mg per cubic centimeter to 280 mg per cubic centimeter.

[0046] Preferably, the RTD of the aerosol-generating substrate rod is less than about 10 millimeters HO. More preferably, the RTD of the aerosol-generating substrate rod is less than 9 millimeters HO. Even more preferably, the RTD of the aerosol-generating substrate rod is less than 8 millimeters HO.

[0047] Preferably, the RTD of the aerosol-generating substrate rod is at least 4 millimeters HO. More preferably, the RTD of the aerosol-generating substrate rod is at least 5 millimeters HO. Even more preferably, the RTD of the aerosol-generating substrate rod is at least 6 millimeters HO.

[0048] In some embodiments, the RTD of the rod of the aerosol-generating substrate is between 4 millimeters HO and 10 millimeters HO, preferably between 5 millimeters HO and 10 millimeters HO, and preferably between 6 millimeters HO and 25 millimeters HO. In other embodiments, the RTD of the rod of the aerosol-generating substrate is between 4 millimeters HO and 20 millimeters HO, preferably between 5 millimeters HO and 18 millimeters HO, and preferably between 6 millimeters HO and 16 millimeters HO. In further embodiments, the RTD of the rod of the aerosol-generating substrate is between 4 millimeters HO and 15 millimeters HO, preferably between 5 millimeters HO and 14 millimeters HO, and more preferably between 6 millimeters HO and 12 millimeters HO.

[0049] The aerosol-generating substrate may be a solid aerosol-generating substrate. Preferably, the aerosol-generating substrate comprises an aerosol former. The aerosol former may be any suitable known compound or mixture of compounds that promotes the formation of a dense, stable aerosol during use. The aerosol former may promote the aerosol to be substantially resistant to thermal decomposition at temperatures typically encountered during use of the aerosol-generating article. Suitable aerosol formers include, for example, polyhydric alcohols (e.g., triethylene glycol, 1,3-butanediol, propylene glycol, glycerin, etc.), esters of polyhydric alcohols (e.g., glycerol mono-, di-, or triacetate, etc.), aliphatic esters of mono-, di-, or polycarboxylic acids (e.g., dimethyl dodecanedioate, dimethyl tetradecanedioate, etc.), and combinations thereof.

[0050] The aerosol former preferably comprises one or more of glycerin and propylene glycol. The aerosol former may consist of glycerin, or propylene glycol, or a combination of glycerin and propylene glycol.

[0051] Preferably, the aerosol-generating substrate comprises at least 5 percent by weight of aerosol formers based on the dry weight of the aerosol-generating substrate, more preferably at least 6 percent by weight of aerosol formers based on the dry weight of the aerosol-generating substrate, and more preferably at least 8 percent by weight of aerosol formers based on the dry weight of the aerosol-generating substrate.

[0052] Preferably, the aerosol-generating substrate comprises less than 90 percent aerosol formers by weight, based on the dry weight of the aerosol-generating substrate, more preferably less than 80 percent aerosol formers by weight, based on the dry weight of the aerosol-generating substrate, more preferably less than 70 percent aerosol formers by weight, based on the dry weight of the aerosol-generating substrate, more preferably less than 60 percent aerosol formers by weight, based on the dry weight of the aerosol-generating substrate, more preferably less than 50 percent aerosol formers by weight, based on the dry weight of the aerosol-generating substrate, and more preferably less than 40 percent aerosol formers by weight, based on the dry weight of the aerosol-generating substrate.

[0053] More preferably, the aerosol-generating substrate comprises less than 30 percent aerosol formers by weight based on the dry weight of the aerosol-generating substrate, more preferably less than 25 percent aerosol formers by weight based on the dry weight of the aerosol-generating substrate, and more preferably less than 20 percent aerosol formers by weight based on the dry weight of the aerosol-generating substrate.

[0054] For example, the aerosol-generating substrate may comprise from 5 to 30 percent by weight of aerosol-forming material, based on the dry weight of the aerosol-generating substrate, more preferably from 6 to 25 percent by weight of aerosol-forming material, based on the dry weight of the aerosol-generating substrate, and more preferably from 10 to 20 percent by weight of aerosol-forming material, based on the dry weight of the aerosol-generating substrate.

[0055] For example, the aerosol-generating substrate may preferably contain 5 to 30 weight percent glycerin based on the dry weight of the aerosol-generating substrate, more preferably 6 to 25 weight percent glycerin based on the dry weight of the aerosol-generating substrate, and more preferably 10 to 20 weight percent glycerin based on the dry weight of the aerosol-generating substrate. In certain preferred embodiments of the present invention, the aerosol-generating substrate comprises shredded tobacco material. For example, the shredded tobacco material may be in the form of cut filler, as described in more detail below. Alternatively, the shredded tobacco material may be in the form of a shredded sheet of homogenized tobacco material. Suitable homogenized tobacco materials for use in the present invention are described below.

[0056] In the context of this specification, the term "cut filler" is used to describe a blend of finely chopped plant material, such as tobacco plant material, specifically including one or more of leaf blades, processed stems and veins, and homogenized plant material.

[0057] Cut filler may also include other cuts, filler tobacco, or casings.

[0058] Preferably, the cut filler comprises at least 25 percent plant leaf lamina, more preferably at least 50 percent plant leaf lamina, even more preferably at least 75 percent plant leaf lamina, and most preferably at least 90 percent plant leaf lamina. Preferably, the plant material is one of tobacco, mint, tea, and cloves. Most preferably, the plant material is tobacco. However, as discussed in more detail below, the present invention is equally applicable to other plant materials that, upon application of heat, have the ability to release a substance that can then form an aerosol.

[0059] Preferably, the cut filler comprises tobacco plant material including the blades of one or more of bright tobacco, dark tobacco, aromatic tobacco, and filler tobacco. For purposes of the present invention, the term "tobacco" describes any plant of the genus Nicotiana.

[0060] Bright tobacco is generally a tobacco with large, light-colored leaves. Throughout this specification, the term "bright tobacco" is used to refer to flue-cured tobacco. Examples of bright tobacco include Chinese flue-cured tobacco, Brazilian flue-cured tobacco, American flue-cured tobacco (such as Virginia tobacco), Indian flue-cured tobacco, Tanzanian flue-cured tobacco, or other African flue-cured tobacco. Bright tobacco is characterized by a high sugar-to-nitrogen ratio. From a sensory perspective, bright tobacco is a tobacco type that, after curing, has a spicy, lively sensation. In the context of the present invention, bright tobacco is tobacco having a reducing sugar content of about 2.5 percent to about 20 percent based on dry weight of the leaf and a total ammonia content of less than about 0.12 percent based on dry weight of the leaf. Reducing sugars include, for example, glucose or fructose. Total ammonia includes, for example, ammonia and ammonia salts.

[0061] Dark tobacco is generally tobacco with large, dark-colored leaves. Throughout this specification, the term "dark tobacco" is used to refer to air-cured tobacco. Additionally, dark tobacco may be fermented. This category also includes tobacco primarily used for chewing tobacco, snuff, cigar tobacco, and pipe blends. Typically, these dark tobaccos are air-cured and, in some cases, fermented. From a sensory perspective, dark tobacco is a tobacco type with a smoky, dark cigar-type sensation after curing. Dark tobacco is characterized by a low sugar-to-nitrogen ratio. Examples of dark tobacco are Malawi or other African burley, dark-cured Brazilian galpao, san-cured, or air-cured Indonesian kasturi. According to the present invention, dark tobacco is tobacco with a reducing sugar content of less than about 5 percent based on dry weight of the leaf and a total ammonia content of about 0.5 percent or less based on dry weight of the leaf.

[0062] Aromatic tobaccos are often tobaccos with small, light-colored leaves. Throughout this specification, the term "aromatic tobacco" is used in contrast to other tobaccos with a high aromatic content, e.g., essential oil content. From a sensory perspective, aromatic tobaccos are tobacco types that, after curing, have a spicy and fragrant sensation. Examples of aromatic tobaccos include Greek Orient, Turkish Orient, and Semi-Orient tobaccos, as well as fire-cured, US Burley (e.g., Perique), Rustica, US Burley, or Maryland. Filler tobacco is not a specific tobacco type, but includes tobacco types that are primarily used to complement other tobacco types used in blends and do not contribute a specific characteristic aroma direction to the final product. Examples of filler tobaccos are the stems, midribs, or petioles of other tobacco types. A specific example could be flue-cured stems of the lower petiole of Brazilian flue-cured petioles.

[0063] The cut filler suitable for use in the present invention may generally be similar to the cut filler used in conventional smoking articles. The cut width of the cut filler is preferably 0.3 mm to 2.0 mm, more preferably 0.5 mm to 1.2 mm, and most preferably 0.6 mm to 0.9 mm. The cut width may play a role in the distribution of heat inside the rod of the aerosol-generating substrate. The cut width may also play a role in the draw resistance of the article. Furthermore, the cut width may affect the overall density of the aerosol-generating substrate as a whole.

[0064] The strand length of cut filler is somewhat random, since the length of the strand depends on the overall size of the object from which it is cut. Nevertheless, longer strands can be cut by conditioning the material before cutting, for example, by controlling the moisture content and overall fineness of the material. Preferably, the strands have a length of about 10 millimeters to about 40 millimeters, and the strands are then aligned to form the aerosol-generating substrate rod. Of course, if the strands are arranged within the aerosol-generating substrate rod with a longitudinal extension of less than 40 millimeters, the final aerosol-generating substrate rod may contain strands that are, on average, shorter than the original strand length. Preferably, the strand length of cut filler is such that about 20 percent to 60 percent of the strands extend along the entire length of the aerosol-generating substrate rod. This prevents the strands from easily detaching from the aerosol-generating substrate rod.

[0065] In a preferred embodiment, the weight of the cut filler is between 80 milligrams and 400 milligrams, preferably between 150 milligrams and 250 milligrams, and more preferably between 170 milligrams and 220 milligrams. This amount of cut filler typically provides sufficient material for aerosol formation. Additionally, in light of the aforementioned constraints on diameter and size, this allows for a balanced density of the aerosol-generating substrate rod between energy uptake, draw resistance, and fluid passage within the aerosol-generating substrate rod when the aerosol-generating substrate includes plant material.

[0066] The cut filler is preferably impregnated with the aerosol former. Impregnation of the cut filler can be achieved by spraying or other suitable application methods. The aerosol former can be added to the blend during preparation of the cut filler. For example, the aerosol former can be applied to the blend in a direct conditioning casing cylinder (DCCC). Conventional machinery can be used to add the aerosol former to the cut filler. The aerosol former can be any suitable known compound or mixture of compounds that promotes the formation of a dense, stable aerosol during use. The aerosol former can promote the aerosol to be substantially resistant to thermal decomposition at temperatures typically encountered during use of the aerosol-generating article. Suitable aerosol formers are, for example, polyhydric alcohols (such as triethylene glycol, 1,3-butanediol, propylene glycol, and glycerin), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids (such as dimethyl dodecanedioate and dimethyl tetradecanedioate), and combinations thereof.

[0067] The aerosol former preferably comprises one or more of glycerin and propylene glycol. The aerosol former may consist of glycerin, or propylene glycol, or a combination of glycerin and propylene glycol.

[0068] Preferably, the amount of aerosol former is at least 5 weight percent based on the dry weight of the cut filler, preferably 5 to 30 weight percent based on the dry weight of the cut filler, more preferably 6 to 20 weight percent based on the dry weight of the cut filler, for example, 8 to 15 weight percent based on the dry weight of the cut filler. When the aerosol former is added to the cut filler in the amounts described above, the cut filler can become relatively sticky. This advantageously helps to hold the cut filler in place within the article, as the cut filler particles tend to adhere not only to surrounding cut filler particles but also to surrounding surfaces (e.g., the inner surface of the wrapper surrounding the cut filler).

[0069] In some embodiments, the amount of aerosol former has a target value of about 13 weight percent based on the dry weight of the cut filler. The most effective amount of aerosol former also depends on the cut filler and whether the cut filler contains plant lamina or homogenized plant material. For example, the type of cut filler, among other factors, determines the extent to which the aerosol former can facilitate the release of material from the cut filler.

[0070] For these reasons, a rod of aerosol-generating substrate comprising cut fillers as described above has the ability to efficiently generate sufficient aerosol at relatively low temperatures: temperatures of 150°C to 200°C in a heating chamber may be sufficient for one such cut filler to generate a sufficient amount of aerosol, whereas temperatures of about 250°C are typically employed in aerosol-generating devices using cast tobacco leaf sheets.

[0071] A further advantage associated with operating at lower temperatures is that the need for cooling the aerosol is reduced. Because lower temperatures are generally used, simpler cooling mechanisms may be sufficient. This in turn allows for the use of simpler and less complex structures for the aerosol-generating article.

[0072] In another preferred embodiment, the aerosol-generating substrate comprises homogenized plant material, preferably homogenized tobacco material.

[0073] As used herein, the term "homogenized plant material" encompasses any plant material formed by agglomeration of plant particles. For example, a sheet or web of homogenized tobacco material for an aerosol-generating substrate of the present invention may be formed by agglomerating particles of tobacco material obtained by grinding, milling, or comminuting plant material and, optionally, one or more of tobacco lamina and tobacco stems. Homogenized plant material may be produced by casting, extrusion, a papermaking process, or any other suitable process known in the art.

[0074] The homogenized plant material can be provided in any suitable form.

[0075] In some embodiments, the homogenized plant material may be in the form of one or more sheets. The term "sheet" as used herein with respect to the present invention describes a laminar element having a width and length that is significantly greater than its thickness.

[0076] The homogenized plant material may be in the form of a plurality of pellets or granules.

[0077] The homogenized plant material may be in the form of multiple strands, pieces, or fragments. As used herein, the term "strand" describes an elongated element of material having a length substantially greater than its width and thickness. The term "strand" should be considered to encompass pieces, fragments, and any other homogenized plant material having a similar morphology. Strands of homogenized plant material may be formed from a sheet of homogenized plant material, for example, by cutting or shredding, or by other methods, such as extrusion methods.

[0078] In some embodiments, the strands may be formed in situ within the aerosol-generating substrate as a result of splitting or breaking down the sheet of homogenized plant material during the formation of the aerosol-generating substrate, e.g., as a result of crimping. The strands of homogenized plant material within the aerosol-generating substrate may be separated from one another. Alternatively, each strand of homogenized plant material within the aerosol-generating substrate may be at least partially connected to adjacent strands along its length. For example, adjacent strands may be connected by one or more fibers. This may occur, for example, when strands are formed due to splitting a sheet of homogenized plant material during the manufacture of the aerosol-generating substrate, as described above.

[0079] As noted above, when the homogenized plant material is in the form of one or more sheets, the sheets may be produced by a casting process. Alternatively, the sheets of homogenized plant material may be produced by a papermaking process.

[0080] One or more sheets as described herein may each individually have a thickness of 100 micrometers to 600 micrometers, preferably 150 micrometers to 300 micrometers, and most preferably 200 micrometers to 250 micrometers. Individual thickness refers to the thickness of an individual sheet, while combined thickness refers to the total thickness of all sheets comprising the aerosol-generating substrate. For example, if the aerosol-generating substrate is formed from two individual sheets, the combined thickness is the thickness of the two individual sheets, or the sum of the measured thicknesses of the two sheets, stacked within the aerosol-generating substrate.

[0081] One or more of the sheets described herein may each individually have a basis weight of from 100 grams per square meter to 600 grams per square meter.

[0082] One or more sheets as described herein may each individually have a density of from 0.3 grams per cubic centimeter to 1.3 grams per cubic centimeter, preferably from 0.7 grams per cubic centimeter to 1.0 grams per cubic centimeter.

[0083] In embodiments of the invention in which the aerosol-generating substrate comprises one or more sheets of homogenized plant material, the sheets are preferably in the form of an assembly of one or more sheets. As used herein, the term "assembly" means that the sheets of homogenized plant material are coiled, folded, or otherwise compressed or contracted in a direction substantially transverse to the cylindrical axis of the plug or rod.

[0084] One or more sheets of homogenized plant material may be gathered transversely to their longitudinal axes and surrounded by a wrapper to form a continuous rod or plug.

[0085] One or more sheets of homogenized plant material may advantageously be crimped or similarly treated. As used herein, the term "crimped" means a sheet having a plurality of substantially parallel ridges or corrugations. One or more sheets of homogenized plant material may be embossed, debossed, perforated, or otherwise deformed to provide texture on one or both sides of the sheet.

[0086] Preferably, one or more sheets of homogenized plant material can be crimped to have a plurality of ridges or corrugations that are substantially parallel to the cylindrical axis of the plug. This process advantageously facilitates assembling the crimped sheets of homogenized plant material to form a plug. Preferably, one or more sheets of homogenized plant material can be assembled. Of course, the crimped sheets of homogenized plant material can alternatively or additionally have a plurality of substantially parallel ridges or corrugations that form acute or obtuse angles with respect to the cylindrical axis of the plug. The sheet can be crimped to an extent that the integrity of the sheet is interrupted at the plurality of parallel ridges or corrugations, causing separation of the material and resulting in the formation of pieces, strands, or strips of homogenized plant material.

[0087] One or more sheets of homogenized plant material may be cut into strands, as mentioned above. In such embodiments, the aerosol-generating substrate includes a plurality of strands of homogenized plant material. The strands may be used to form plugs. Typically, the width of such strands is about 5 millimeters, about 4 millimeters, about 3 millimeters, about 2 millimeters, or less. The length of the strands may be greater than about 5 millimeters, about 5 millimeters to about 15 millimeters, about 8 millimeters to about 12 millimeters, or even about 12 millimeters. Preferably, the strands have substantially the same length as each other.

[0088] The homogenized plant material may comprise up to about 95 weight percent plant particles on a dry weight basis. Preferably, the homogenized plant material comprises up to 90 weight percent plant particles, more preferably up to 80 weight percent plant particles, more preferably up to 70 weight percent plant particles, more preferably up to 60 weight percent plant particles, and more preferably up to about 50 weight percent plant particles on a dry weight basis.

[0089] For example, the homogenized plant material may contain, on a dry weight basis, 2.5 weight percent to 95 weight percent plant particles, or 5 weight percent to 90 weight percent plant particles, or 10 weight percent to 80 weight percent plant particles, or 15 weight percent to 70 weight percent plant particles, or 20 weight percent to 60 weight percent plant particles, or 30 weight percent to 50 weight percent plant particles.

[0090] In certain embodiments of the present invention, the homogenized plant material is a homogenized tobacco material comprising tobacco particles. The sheets of homogenized tobacco material used in such embodiments of the present invention may have a tobacco content of at least about 40 weight percent on a dry weight basis, more preferably at least about 50 weight percent on a dry weight basis, more preferably at least about 70 weight percent on a dry weight basis, and most preferably at least about 90 weight percent on a dry weight basis.

[0091] For purposes of the present invention, the term "tobacco particles" refers to particles of any plant material of the Nicotiana species. The term "tobacco particles" encompasses ground or powdered tobacco lamina, ground or powdered tobacco stems, tobacco dust, tobacco fines, and other particulate tobacco by-products formed during tobacco processing, handling, and shipping. In preferred embodiments, the tobacco particles are derived substantially entirely from tobacco lamina. In contrast, isolated nicotine and nicotine salts, although tobacco-derived compounds, are not considered tobacco particles for purposes of the present invention and are not included in the proportion of particulate plant material.

[0092] The homogenized plant material may further include one or more aerosol formers. Upon volatilization, the aerosol formers can carry other vaporized compounds released from the aerosol-generating substrate upon heating, such as nicotine and flavorants in the aerosol. Suitable aerosol formers for inclusion in the homogenized plant material are known in the art and include, but are not limited to, polyhydric alcohols (such as triethylene glycol, propylene glycol, 1,3-butanediol, and glycerol), esters of polyhydric alcohols (such as glycerol mono-, di-, or triacetate), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate and tetradecanedioate).

[0093] The homogenized plant material may have an aerosol former content of 5 to 30 percent by weight on a dry weight basis (such as 10 to 25 percent by weight on a dry weight basis, or 15 to 20 percent by weight on a dry weight basis). The aerosol former may act as a humectant in the homogenized plant material.

[0094] In certain embodiments, the aerosol-generating article further comprises a susceptor element within the rod of the aerosol-generating substrate, for example, an elongated susceptor element that may be disposed substantially longitudinally within the rod of the aerosol-generating substrate and in thermal contact with the aerosol-generating substrate.

[0095] As used herein with respect to the present invention, the term "susceptor element" refers to a material capable of converting electromagnetic energy into heat. When located within a varying electromagnetic field, induced eddy currents in the susceptor element cause the susceptor element to heat. Because the susceptor element is located in thermal contact with the aerosol-generating substrate, the aerosol-generating substrate is heated by the susceptor element.

[0096] When used to describe a susceptor element, the term "elongated" means that the susceptor element 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.

[0097] The susceptor elements are disposed substantially longitudinally within the rod, meaning that the length dimension of the elongated susceptor elements is disposed approximately parallel to the longitudinal direction of the rod, for example, within ±10 degrees of parallel to the longitudinal direction of the rod. In a preferred embodiment, the elongated susceptor elements may be positioned at a radially central location within the rod and extend along the longitudinal axis of the rod.

[0098] Preferably, the susceptor element extends all the way to the downstream end of the rod of the aerosol-generating substrate. In some embodiments, the susceptor element may extend all the way to the upstream end of the rod of the aerosol-generating substrate. In particularly preferred embodiments, the susceptor element has substantially the same length as the rod of the aerosol-generating substrate, extending from the upstream end of the rod to the downstream end of the rod.

[0099] The susceptor elements are preferably in the form of pins, rods, strips or blades.

[0100] The susceptor element preferably has a length of between 10 millimeters and 40 millimeters, for example between 15 millimeters and 35 millimeters, or between 17 millimeters and 30 millimeters.

[0101] The susceptor element preferably has a length of 5 millimeters to 15 millimeters, for example, 6 millimeters to 12 millimeters, or 8 millimeters to 10 millimeters.

[0102] The susceptor element preferably has a width of between 1 mm and 5 mm.

[0103] The susceptor element may generally have a thickness of 0.01 millimeters to 2 millimeters, for example, 0.5 millimeters to 2 millimeters. In some embodiments, the susceptor element preferably has a thickness of 10 micrometers to 500 micrometers, more preferably 10 micrometers to 100 micrometers.

[0104] When the susceptor element has a constant cross section, for example a circular cross section, it has a preferred width or diameter of 1 millimeter to 5 millimeters.

[0105] When the susceptor elements have the form of strips or blades, the strips or blades preferably have a rectangular shape with a width of 2 to 8 millimeters, more preferably 3 to 5 millimeters. As an example, a susceptor element in the form of a blade strip may have a width of 4 millimeters.

[0106] When the susceptor elements have the form of strips or blades, the strips or blades preferably have a rectangular shape and a thickness of 0.03 to 0.15 mm, more preferably 0.05 to 0.09 mm. As an example, a susceptor element in the form of a blade strip may have a thickness of 0.07 mm.

[0107] In a preferred embodiment, the elongated susceptor elements are in the form of strips or blades, preferably having a rectangular shape and a thickness of between 55 micrometers and 65 micrometers.

[0108] More preferably, the elongated susceptor elements have a thickness of between 57 micrometers and 63 micrometers. Even more preferably, the elongated susceptor elements have a thickness of between 58 micrometers and 62 micrometers. In a particularly preferred embodiment, the elongated susceptor elements have a thickness of 60 micrometers.

[0109] The elongated susceptor elements preferably have a length that is the same as or shorter than the length of the aerosol-generating substrate.The elongated susceptor elements preferably have the same length as the aerosol-generating substrate.

[0110] The susceptor element may be formed from any material that can be inductively heated to a temperature sufficient to generate an aerosol from the aerosol-generating substrate. Preferred susceptor elements comprise metal or carbon.

[0111] Preferred susceptor elements may include or consist of a ferromagnetic material, such as a ferromagnetic alloy, ferritic iron, or ferromagnetic steel or stainless steel. Suitable susceptor elements may be or include aluminum. Preferred susceptor elements may be formed from 400 series stainless steel, such as grade 410, grade 420, or grade 430 stainless steel. Different materials dissipate different amounts of energy when placed in electromagnetic fields of similar frequency and field strength.

[0112] Thus, any of the susceptor element parameters, such as type of material, length, width, and thickness, can be varied to provide a desired power distribution within a known electromagnetic field. Preferred susceptor elements may be heated to temperatures in excess of 250 degrees Celsius.

[0113] Suitable susceptor elements may include a non-metallic core having a metal layer, such as a metal band formed on the surface of the ceramic core. The susceptor element may have a protective outer layer, such as a protective ceramic or glass layer, encapsulating the susceptor element. The susceptor element may include a protective coating formed of glass, ceramic, or an inert metal formed over a core of susceptor element material.

[0114] The susceptor element is disposed in thermal contact with the aerosol-generating substrate, such that as the temperature of the susceptor element increases, the aerosol-generating substrate is heated and an aerosol is formed. Preferably, the susceptor element is disposed in direct physical contact with the aerosol-generating substrate, for example, within the aerosol-generating substrate.

[0115] As set forth above, the rod of aerosol-generating substrate may be surrounded by a wrapper. The wrapper surrounding the rod of aerosol-generating substrate may be a paper wrapper or a non-paper wrapper. Suitable paper wrappers for use in certain embodiments of the present invention are known in the art and include, but are not limited to, cigarette paper and filter plug wrap. Suitable non-paper wrappers for use in certain embodiments of the present invention are known in the art and include, but are not limited to, sheets of homogenized tobacco material.

[0116] The paper wrapper may have a basis weight of at least 15 gsm (grams per square meter), preferably at least 20 gsm. The paper wrapper may have a basis weight of 35 gsm or less, preferably 30 gsm or less. The paper wrapper may have a basis weight of 15 gsm to 35 gsm, preferably 20 gsm to 30 gsm. In a preferred embodiment, the paper wrapper may have a basis weight of 25 gsm. The paper wrapper may have a thickness of at least 25 micrometers, preferably at least 30 micrometers, and more preferably at least 35 micrometers. The paper wrapper may have a thickness of about 55 micrometers or less, preferably about 50 micrometers or less, and more preferably about 45 micrometers or less. The paper wrapper may have a thickness of 25 micrometers to 55 micrometers, preferably 30 micrometers to 50 micrometers, and more preferably 35 micrometers to 45 micrometers. In one preferred embodiment, the paper wrapper may have a thickness of 40 micrometers.

[0117] In certain preferred embodiments, the wrapper may be formed from a laminate material comprising multiple layers. Preferably, the wrapper is formed from an aluminum co-laminate sheet. The use of an aluminum co-laminate sheet advantageously prevents combustion of the aerosol-generating substrate if the aerosol-generating substrate is to be ignited rather than heated in the intended manner.

[0118] The paper layer of the co-laminate sheet may have a basis weight of at least 35 gsm, preferably at least 40 gsm. The paper layer of the co-laminate sheet may have a basis weight of 55 gsm or less, preferably 50 gsm or less. The paper layer of the co-laminate sheet may have a basis weight of 35 gsm to 55 gsm, preferably 40 gsm to 50 gsm. In one preferred embodiment, the paper layer of the co-laminate sheet may have a basis weight of 45 gsm.

[0119] The paper layer of the co-laminate sheet may have a thickness of at least 50 micrometers, preferably at least 55 micrometers, more preferably at least 60 micrometers. The paper layer of the co-laminate sheet may have a thickness of 80 micrometers or less, preferably 75 micrometers or less, more preferably 70 micrometers or less.

[0120] The paper layer of the co-laminate sheet may have a thickness of about 50 micrometers to about 80 micrometers, preferably about 55 micrometers to about 75 micrometers, and more preferably about 60 micrometers to about 70 micrometers. In one preferred embodiment, the paper layer of the co-laminate sheet may have a thickness of 65 micrometers.

[0121] The metal layer of the co-laminate sheet may have a basis weight of at least 12 gsm, preferably at least 15 gsm. The metal layer of the co-laminate sheet may have a basis weight of 25 gsm or less, preferably 20 gsm or less. The metal layer of the co-laminate sheet may have a basis weight of 12 gsm to 25 gsm, preferably 15 gsm to 20 gsm. In one preferred embodiment, the metal layer of the co-laminate sheet may have a basis weight of 17 gsm.

[0122] The metal layer of the co-laminate sheet may have a thickness of at least 2 micrometers, preferably at least 3 micrometers, more preferably at least 5 micrometers. The metal layer of the co-laminate sheet may have a thickness of 15 micrometers or less, preferably 12 micrometers or less, more preferably 10 micrometers or less.

[0123] The metal layer of the co-laminate sheet may have a thickness of about 2 micrometers to about 15 micrometers, preferably about 3 micrometers to about 12 micrometers, and more preferably about 5 micrometers to about 10 micrometers. In one preferred embodiment, the metal layer of the co-laminate sheet may have a thickness of 6 micrometers.

[0124] The wrapper surrounding the rod of aerosol-generating substrate 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.

[0125] The PVOH or silicon may be applied to the paper layer as a surface coating, such as being disposed on the outer surface of the paper layer of the wrapper surrounding the rod of the aerosol-generating substrate. The PVOH or silicon (or polysiloxane) may be disposed on the outer surface of the paper layer of the wrapper and may form a layer. The PVOH or silicon (or polysiloxane) may be disposed on the inner surface of the paper layer of the wrapper. The PVOH or silicon (or polysiloxane) may be disposed on the inner surface of the paper layer of the aerosol-generating article and may form a layer. The PVOH or silicon (or polysiloxane) may be disposed on both the inner and outer surfaces of the paper layer of the wrapper. The PVOH or silicon (or polysiloxane) may be disposed on both the inner and outer surfaces of the paper layer of the wrapper and may form a layer.

[0126] The PVOH or silicon (or polysiloxane)-containing paper wrapper may have a basis weight of at least 20 gsm, preferably at least 25 gsm, and more preferably at least 30 gsm. The PVOH or silicon (or polysiloxane)-containing paper wrapper may have a basis weight of 50 gsm or less, preferably 45 gsm or less, and more preferably 40 gsm or less. The PVOH or silicon (or polysiloxane)-containing paper wrapper may have a basis weight of 20 gsm to 50 gsm, preferably 25 gsm to 45 gsm, and more preferably 30 gsm to 40 gsm. In a particularly preferred embodiment, the PVOH or silicon (or polysiloxane)-containing paper wrapper may have a basis weight of 35 gsm.

[0127] The PVOH or silicon (or polysiloxane)-containing paper wrapper may have a thickness of at least 25 micrometers, preferably at least 30 micrometers, and more preferably at least 35 micrometers. The PVOH or silicon (or polysiloxane)-containing paper wrapper may have a thickness of 50 micrometers or less, preferably 45 micrometers or less, and more preferably 40 micrometers or less. The PVOH or silicon (or polysiloxane)-containing paper wrapper may have a thickness of 25 micrometers to 50 micrometers, preferably 30 micrometers to 45 micrometers, and more preferably 35 micrometers to 40 micrometers. In a particularly preferred embodiment, the PVOH or silicon (or polysiloxane)-containing paper wrapper may have a thickness of 37 micrometers.

[0128] The wrapper surrounding the rod of aerosol-generating substrate may include a flame-retardant composition comprising one or more flame-retardant compounds. The term "flame-retardant compound" is used herein to describe 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. In practice, the flame-retardant compound may be activated by the presence of an ignition source and is adapted to prevent or slow the further development of ignition by a variety of different physical and chemical mechanisms.

[0129] Flame retardant compositions may typically further include one or more non-flame retardant compounds, i.e., one or more compounds (solvents, excipients, fillers, etc.) that do not actively contribute to providing flammability protection to the carrier substrate, but are used to facilitate application of the flame retardant compound(s) onto or within the wrapper, or both. Some of the non-flame retardant compounds (e.g., solvents) of the flame retardant composition may be volatile and may evaporate from the wrapper as it dries after the flame retardant composition is applied onto or within the wrapping substrate, or both. Thus, while these non-flame retardant compounds form part of the formulation of the flame retardant composition, they may no longer be present, or may only be detectable in trace amounts, within the wrapper of the aerosol-generating article.

[0130] Many suitable flame retardant compounds are known to those skilled in the art. In particular, several flame retardant compounds and formulations suitable for treating cellulosic materials are known and disclosed and may find use in the manufacture of wrappers for aerosol-generating articles according to the present invention.

[0131] For example, the flame retardant composition may comprise a polymer and a mixed salt based on at least one mono-, di-, and / or tricarboxylic acid, at least one polyphosphoric acid, pyrophosphoric acid, and / or phosphoric acid, and a hydroxide or salt of an alkali or alkaline earth metal, where the at least one mono-, di-, and / or tricarboxylic acid and the hydroxide or salt form a carboxylate salt and at least one polyphosphoric acid, and the pyrophosphoric acid and / or phosphoric acid and the hydroxide or salt form a phosphate salt. Preferably, the flame retardant composition further comprises a carbonate salt of an alkali or alkaline earth metal. Alternatively, the flame retardant composition may comprise at least one C 10 The cellulose may be modified with the above fatty acids, tall oil fatty acid (TOFA), phosphorylated linseed oil, or phosphorylated lower corn oil. Preferably, the cellulose may be modified with at least one C 10 The fatty acids are selected from the group consisting of capric acid, myristic acid, palmitic acid, and combinations thereof.

[0132] In wrappers containing a flame-retardant composition suitable for use in aerosol-generating articles according to the present invention, the flame-retardant composition may be provided within a treated portion of the wrapper. This means that the flame-retardant composition is applied onto or through a corresponding portion of the wrapping substrate, or both. Thus, in the treated portion, the wrapper has a total dry basis weight greater than the dry basis weight of the wrapping substrate. The treated portion of the wrapper may extend over at least 10 percent of the outer surface area of ​​the rod of aerosol-generating substrates surrounded by the wrapper, preferably over at least 20 percent of the outer surface area of ​​the rod of aerosol-generating substrates surrounded by the wrapper, more preferably over at least 40 percent of the outer surface area of ​​the rod of aerosol-generating substrates, and even more preferably over at least 60 percent of the outer surface area of ​​the rod of aerosol-generating substrates. Most preferably, the treated portion of the wrapper extends over at least 80 percent of the outer surface area of ​​the rod of aerosol-generating substrates. In particularly preferred embodiments, the treated portion of the wrapper extends over at least 90 or even 95 percent of the outer surface area of ​​the rod of aerosol-generating substrates. Most preferably, the treated portion of the wrapper covers substantially the entire outer surface area of ​​the rod of aerosol-generating substrate.

[0133] The wrapper containing the flame retardant composition may have a basis weight of at least 20 gsm, preferably at least 25 gsm, and more preferably at least 30 gsm. The wrapper containing the flame retardant composition may have a basis weight of 45 gsm or less, preferably 40 gsm or less, and more preferably 35 gsm or less. The wrapper containing the flame retardant composition may have a basis weight of 20 gsm to 45 gsm, preferably 25 gsm to 40 gsm, and more preferably 30 gsm to 35 gsm. In some preferred embodiments, the wrapper containing the flame retardant composition may have a basis weight of 33 gsm.

[0134] The wrapper containing the flame retardant composition may have a thickness of at least 25 micrometers, preferably at least 30 micrometers, and even more preferably 35 micrometers. The wrapper containing the flame retardant composition may have a thickness of 50 micrometers or less, preferably 45 micrometers or less, and even more preferably 40 micrometers or less. In some embodiments, the wrapper containing the flame retardant composition may have a thickness of 37 micrometers.

[0135] The aerosol-generating article according to the present disclosure may further comprise an upstream section located upstream of the rod of the aerosol-generating substrate. The upstream section is preferably located immediately upstream of the rod of the aerosol-generating substrate. The upstream section preferably extends between the upstream end of the aerosol-generating article and the rod of the aerosol-generating substrate. The upstream section may comprise one or more upstream elements located upstream of the rod of the aerosol-generating substrate. Such one or more upstream elements are described in the present disclosure.

[0136] The aerosol-generating article of the present invention preferably comprises an upstream element located upstream of and adjacent to the aerosol-generating substrate. The upstream element advantageously prevents direct physical contact with the upstream end of the aerosol-generating substrate. For example, if the aerosol-generating substrate comprises a susceptor element, the upstream element may prevent direct physical contact with the upstream end of the susceptor element. This helps to prevent displacement or deformation of the susceptor element during handling or transportation of the aerosol-generating article. This in turn helps to fix the shape and position of the susceptor element. Furthermore, the presence of the upstream element helps to prevent any loss of the substrate, which may be advantageous, for example, when the substrate contains particulate plant material.

[0137] Where the aerosol-generating substrate comprises shredded tobacco, such as tobacco cut filler, the upstream section or element thereof may additionally serve to prevent loss of loose particles of tobacco from the upstream end of the article, which may be particularly important, for example, when the shredded tobacco has a relatively low density.

[0138] The upstream section or upstream element thereof may also provide at least some coverage to the upstream end of the aerosol-generating substrate that might otherwise be exposed, and therefore may provide some additional protection to the aerosol-generating substrate during storage.

[0139] In the case of an aerosol-generating article intended to be inserted into a cavity in an aerosol-generating device so that the aerosol-generating substrate can be externally heated within the cavity, the upstream section or upstream element thereof may advantageously facilitate insertion of the upstream end of the article into the cavity. The inclusion of an upstream element may additionally protect the rod end of the aerosol-generating substrate during insertion of the article into the cavity, thereby minimizing the risk of damage to the substrate.

[0140] The upstream section, or upstream elements thereof, may also provide an improved appearance to the upstream end of the aerosol-generating article. Furthermore, if desired, the upstream section, or upstream elements thereof, may be used to provide information about the aerosol-generating article, such as information about the brand, flavor, content, or details of the aerosol-generating device with which the aerosol-generating article is intended to be used.

[0141] The upstream element may be a porous plug element. Preferably, the upstream element has a porosity of at least 50 percent along the longitudinal axis of the aerosol-generating article. More preferably, the upstream element has a porosity of between 50 percent and 90 percent along the longitudinal axis. The porosity of the upstream element along the longitudinal axis is defined as 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.

[0142] The upstream element may be made of a porous material or may include a plurality of openings, which may be achieved, for example, by laser drilling, and the plurality of openings are preferably uniformly distributed across the cross section of the upstream element.

[0143] The porosity or permeability of the upstream element may advantageously be designed to provide an aerosol-generating article with a particular overall resistance to draw (RTD) without substantially affecting the filtration provided by other portions of the article.

[0144] The upstream element may be formed from a material that is impermeable to air. In such embodiments, the aerosol-generating article may be configured to allow air to flow into the rod of aerosol-generating substrate through suitable venting means provided in the wrapper.

[0145] In certain preferred embodiments of the present invention, it may be desirable to minimize the RTD of the upstream element. For example, this may be the case for an article intended to be inserted into the cavity of an aerosol-generating device, such that the aerosol-generating substrate is externally heated, as described herein. For such articles, it is desirable to provide the article with the lowest possible RTD, so that the majority of the consumer's RTD experience is provided by the aerosol-generating device, rather than the article.

[0146] Preferably, the RTD of the upstream element is less than 30 millimeters of H2O. More preferably, the RTD of the upstream element is less than 20 millimeters of H2O. Even more preferably, the RTD of the upstream element is 10 millimeters of H2O or less. Even more preferably, the RTD of the upstream element is 5 millimeters of H2O or less. Even more preferably, the RTD of the upstream element is 2 millimeters of H2O or less.

[0147] The RTD of the upstream element may be at least 0.1 millimeters H2O, or at least 0.25 millimeters H2O, or at least 0.5 millimeters H2O.

[0148] In some embodiments, the RTD of the upstream element is between 0.1 millimeters of H2O and 30 millimeters of H2O, preferably between 0.25 millimeters of H2O and 30 millimeters of H2O, and preferably between 0.5 millimeters of H2O and 30 millimeters of H2O. In other embodiments, the RTD of the upstream element is between 0.1 millimeters of H2O and 20 millimeters of H2O, preferably between 0.25 millimeters of H2O and 20 millimeters of H2O, and preferably between 0.5 millimeters of H2O and 20 millimeters of H2O. In further embodiments, the RTD of the upstream element is between 0.1 millimeters of H2O and 10 millimeters of H2O, preferably between 0.25 millimeters of H2O and 10 millimeters of H2O, and more preferably between 0.5 millimeters of H2O and 10 millimeters of H2O. In still further embodiments, the RTD of the upstream element is between 0.1 millimeters of H2O and 5 millimeters of H2O, preferably between 0.25 millimeters of H2O and 5 millimeters of H2O, and more preferably between 0.5 millimeters of H2O and 5 millimeters of H2O. In a further embodiment, the RTD of the upstream element is between 0.1 millimeters H2O and 2 millimeters H2O, preferably between 0.25 millimeters H2O and 2 millimeters H2O, and more preferably between 0.5 millimeters H2O and 2 millimeters H2O.

[0149] Preferably, the upstream element has an RTD of less than 2 millimeters of H2O per millimeter of length, more preferably less than 1.5 millimeters of H2O per millimeter of length, more preferably less than 1 millimeter of H2O per millimeter of length, more preferably less than 0.5 millimeters of H2O per millimeter of length, more preferably less than 0.3 millimeters of H2O per millimeter of length, and more preferably less than 0.2 millimeters of H2O per millimeter of length.

[0150] Preferably, the combined RTD of the upstream section or upstream element thereof and the rod of the aerosol-generating substrate is less than 15 millimeters H2O, more preferably less than 12 millimeters H2O, more preferably less than 10 millimeters H2O.

[0151] 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 "plain" element. The solid plug element may be porous as described above, but does not have a tubular configuration and therefore does not provide a longitudinal flow channel. Preferably, the solid plug element has a substantially uniform cross-section.

[0152] In other preferred embodiments, the upstream element is formed from a hollow tubular segment defining a longitudinal cavity that provides an unrestricted flow channel. In such embodiments, the upstream element can provide protection for the aerosol-generating substrate, as described above, while having a minimal effect on the overall resistance to draw (RTD) and filtration characteristics of the article.

[0153] 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, 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 upstream element thereof.

[0154] Preferably, the wall thickness of the hollow tubular segment is less than 2 millimeters, more preferably less than 1.5 millimeters, and more preferably less than 1 millimeter.

[0155] 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 in 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 material, ceramic, polymeric material, cellulose acetate, cardboard, zeolite, or an aerosol-generating substrate. The upstream element may include a plug of cellulose acetate. The upstream element may also comprise a hollow acetate tube or a cardboard tube.

[0156] The upstream element is preferably formed from a heat resistant material, for example, a material that can withstand temperatures up to 350 degrees Celsius. This ensures that the upstream element is not adversely affected by the heating means for heating the aerosol-generating substrate.

[0157] The upstream section, or an upstream element thereof, preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article. Preferably, the outer diameter of the upstream section, or an upstream element thereof, is between 5 mm and 8 mm, more preferably between 5.25 mm and 7.5 mm, and even more preferably between 5.5 mm and 7 mm.

[0158] Preferably, the upstream section or element has a length of at least 2 millimeters, more preferably at least 3 millimeters, more preferably at least 4 millimeters.

[0159] Preferably, the upstream section or element has a length of 2 to 10 millimeters, more preferably 3 to 8 millimeters, more preferably 2 to 6 millimeters, more preferably 3 to 6 millimeters, more preferably 4 to 8 millimeters, more preferably 4 to 6 millimeters. In a particularly preferred embodiment, the upstream section or element has a length of 5 millimeters. The length of the upstream section or element may be advantageously varied to provide a desired overall length of the aerosol-generating article. For example, if it is desired to reduce the length of one of the other components of the aerosol-generating article, the length of the upstream section or element may be increased to maintain the same overall length of the article.

[0160] Additionally, for articles intended to be externally heated, the length of the upstream section or upstream element thereof can be used to control the position of the aerosol-generating article within the cavity of the aerosol-generating device. This can advantageously ensure that the position of the aerosol-generating substrate within the cavity can be optimized for heating, and also the position of any ventilation.

[0161] The upstream section is preferably surrounded by a wrapper, such as plug wrap, which is preferably a stiff plug wrap, for example, a plug wrap having a basis weight of at least 80 grams per square meter (gsm), or at least 100 gsm, or at least 110 gsm, to provide structural rigidity to the upstream section.

[0162] The upstream section is preferably connected to the rod of the aerosol-generating substrate, and optionally to at least part of the downstream section, by an outer wrapper as described herein.

[0163] As described above, the aerosol-generating article according to the present invention comprises a downstream section located downstream of the rod of aerosol-generating substrate. The downstream section is preferably located immediately downstream of the rod of aerosol-generating substrate. The downstream section of the aerosol-generating article preferably extends between the rod of aerosol-generating substrate 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 this disclosure.

[0164] The length of the downstream section may be at least 40 millimeters. The length of the downstream section may be at least 45 millimeters. The length of the downstream section may be greater than 45 millimeters. The length of the downstream section may be at least 48 millimeters. The length of the downstream section may be at least 50 millimeters.

[0165] The length of the downstream section may be less than 75 millimeters. The length of the downstream section may be 70 millimeters or less. The length of the downstream section may be 65 millimeters or less.

[0166] For example, the length of the downstream section may be 40 mm to 75 mm, or 45 mm to 75 mm, or 48 mm to 75 mm, or 50 mm to 75 mm. In other embodiments, the length of the downstream section may be 40 mm to 70 mm, or 45 mm to 70 mm, or 48 mm to 70 mm, or 50 mm to 70 mm. In other embodiments, the length of the downstream section may be 40 mm to 65 mm, or 45 mm to 65 mm, or 48 mm to 65 mm, or 50 mm to 65 mm.

[0167] Providing a relatively long downstream section ensures that an appropriate length of the aerosol-generating article protrudes from the aerosol-generating device when the article is received therein. Such an appropriate protrusion length facilitates ease of insertion and extraction of the article from the device, and it also ensures that the upstream portion of the article is properly inserted into the device, particularly with reduced risk of damage during insertion.

[0168] The ratio between the length of the downstream section and the overall length of the aerosol-generating article may be less than 0.85. Preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be less than 0.80. More preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be less than 0.75. Even more preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be less than 0.70.

[0169] The ratio between the length of the downstream section and the overall length of the aerosol-generating article may be at least 0.50. Preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be at least 0.55. More preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be at least 0.60. Even more preferably, the ratio between the length of the downstream section and the overall length of the aerosol-generating article may be at least 0.65.

[0170] In some embodiments, the ratio between the length of the downstream section and the overall length of the aerosol-generating article is 0.50 to 0.85, preferably 0.55 to 0.85, more preferably 0.60 to 0.85, and even more preferably 0.65 to 0.85. In other embodiments, the ratio between the length of the downstream section and the overall length of the aerosol-generating article is 0.50 to 0.80, preferably 0.55 to 0.80, more preferably 0.60 to 0.80, and even more preferably 0.65 to 0.80. In further embodiments, the ratio between the length of the downstream section and the overall length of the aerosol-generating article is 0.50 to 0.75, preferably 0.55 to 0.75, more preferably 0.60 to 0.75, and even more preferably 0.65 to 0.75. In a further embodiment, the ratio between the length of the downstream section and the overall length of the aerosol-generating article is between 0.50 and 0.70, preferably between 0.55 and 0.70, more preferably between 0.60 and 0.70, and even more preferably between 0.65 and 0.70.

[0171] The ratio between the length of the downstream section and the length of the upstream section may be less than 30. Preferably, the ratio between the length of the downstream section and the length of the upstream section may be less than 20. More preferably, the ratio between the length of the downstream section and the length of the upstream section may be less than 15. Even more preferably, the ratio between the length of the downstream section and the length of the upstream section may be less than 10.

[0172] The ratio between the length of the downstream section and the length of the upstream section may be at least 4. Preferably, the ratio between the length of the downstream section and the length of the upstream section may be at least 5. More preferably, the ratio between the length of the downstream section and the length of the upstream section may be at least 6. Even more preferably, the ratio between the length of the downstream section and the length of the upstream section may be at least 7.

[0173] In some embodiments, the ratio between the length of the downstream section and the length of the upstream section is 4 to 30, preferably 5 to 30, more preferably 6 to 30, and even more preferably 7 to 18. In other embodiments, the ratio between the length of the downstream section and the length of the upstream section is 4 to 20, preferably 5 to 20, more preferably 6 to 20, and even more preferably 7 to 20. In further embodiments, the ratio between the length of the downstream section and the length of the upstream section is 4 to 15, preferably 5 to 15, more preferably 6 to 15, and even more preferably 7 to 15. In still further embodiments, the ratio between the length of the downstream section and the length of the upstream section is 4 to 10, preferably 5 to 10, more preferably 6 to 10, and even more preferably 7 to 10.

[0174] The ratio between the length of the downstream section and the length of the aerosol-generating substrate rod is preferably at least 1.0. More preferably, the ratio between the length of the downstream section and the length of the aerosol-generating substrate rod is at least 1.25. More preferably, the ratio between the length of the downstream section and the length of the aerosol-generating substrate rod is at least 1.5. More preferably, the ratio between the length of the downstream section and the length of the aerosol-generating substrate rod is at least 1.75.

[0175] The ratio between the length of the downstream section and the length of the aerosol-generating substrate rod is preferably less than 3.5. Preferably, the ratio between the length of the downstream section and the length of the aerosol-generating substrate rod is less than 3.25. More preferably, the ratio between the length of the downstream section and the length of the aerosol-generating substrate rod is less than 3.0. Even more preferably, the ratio between the length of the downstream section and the length of the aerosol-generating substrate rod is less than 2.75.

[0176] In some embodiments, the ratio between the length of the downstream section and the length of the rod of the aerosol-generating substrate is 1.0 to 3.5, preferably 1.25 to 3.5, more preferably 1.50 to 3.5, and even more preferably 1.75 to 3.5. In some embodiments, the ratio between the length of the downstream section and the length of the rod of the aerosol-generating substrate is 1.0 to 3.25, preferably 1.25 to 3.25, more preferably 1.50 to 3.25, and even more preferably 1.75 to 3.25. In further embodiments, the ratio between the length of the downstream section and the length of the rod of the aerosol-generating substrate is 1.0 to 3.0, preferably 1.25 to 3.0, more preferably 1.50 to 3.0, and even more preferably 1.75 to 3.0. In still further embodiments, the ratio between the length of the downstream section and the length of the rod of the aerosol-generating substrate is 1.0 to 2.75, preferably 1.25 to 2.75, more preferably 1.50 to 2.75, and even more preferably 1.75 to 2.75.

[0177] The downstream section of the aerosol-generating article according to the invention preferably comprises a hollow tubular cooling element provided downstream of the rod of the aerosol-generating substrate, which may advantageously provide the aerosol cooling element for the aerosol-generating article.

[0178] The hollow tubular cooling element may be provided immediately downstream of the rod of the aerosol-generating substrate. In other words, the hollow tubular cooling element may abut the downstream end of the rod of the aerosol-generating substrate. 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 embodiments, the downstream section comprises two or more hollow tubular elements, as described below.

[0179] As used throughout this disclosure, the term "hollow tubular element" generally refers to an elongated element that defines a lumen or airflow passage along its longitudinal axis. In particular, the term "tubular" is used hereinafter with reference to a tubular element that has a substantially cylindrical cross-section and defines at least one airflow conduit that establishes uninterrupted fluid communication between the upstream end of the tubular element and the downstream end of the tubular element. However, it will be appreciated that alternative shapes of the tubular element (e.g., alternative cross-sectional shapes) may be possible. A hollow tubular cooling element may be an individual, separate element of an aerosol-generating article, having a defined length and thickness.

[0180] The interior volume defined by the hollow tubular cooling element may be at least 100 cubic millimeters. In other words, the volume of the cavity or lumen defined by the hollow tubular cooling element may be at least 100 cubic millimeters. Preferably, the interior volume defined by the hollow tubular cooling element may be at least 300 cubic millimeters. The interior volume defined by the hollow tubular cooling element may be at least 700 cubic millimeters.

[0181] The interior volume defined by the hollow tubular cooling element may be 1200 cubic millimeters or less. Preferably, the interior volume defined by the hollow tubular cooling element may be 1000 cubic millimeters or less. The interior volume defined by the hollow tubular cooling element may be 900 cubic millimeters or less.

[0182] The interior volume defined by the hollow tubular cooling element may be between 100 and 1200 cubic millimeters. Preferably, the interior volume defined by the hollow tubular cooling element may be between 300 and 1000 cubic millimeters. The interior volume defined by the hollow tubular cooling element may be between 700 and 900 cubic millimeters.

[0183] In the context of the present invention, a hollow tubular cooling element provides an unrestricted flow channel. This means that the hollow tubular cooling element provides a negligible resistance to withdrawal (RTD). The term "negligible RTD" is used to describe an RTD of less than 1 millimeter of HO per 10 millimeters of hollow tubular cooling element length, preferably less than 0.4 millimeters of HO per 10 millimeters of hollow tubular cooling element length, and more preferably less than 0.1 millimeters of HO per 10 millimeters of hollow tubular cooling element length.

[0184] Preferably, the RTD of the hollow tubular cooling element is 10 millimeters HO or less. More preferably, the RTD of the hollow tubular cooling element is 5 millimeters HO or less. Even more preferably, the RTD of the hollow tubular cooling element is 2.5 millimeters HO or less. Even more preferably, the RTD of the hollow tubular cooling element is 2 millimeters HO or less. Even more preferably, the RTD of the hollow tubular cooling element is 1 millimeter HO or less.

[0185] The RTD of the hollow tubular cooling element can be at least 0 millimeters H2O, or at least 0.25 millimeters H2O, or at least 0.5 millimeters H2O, or at least 1 millimeter H2O.

[0186] In some embodiments, the RTD of the hollow tubular cooling element is between 0 millimeters HO and 10 millimeters HO, preferably between 0.25 millimeters HO and 10 millimeters HO, and preferably between 0.5 millimeters HO and 10 millimeters HO. In other embodiments, the RTD of the hollow tubular cooling element is between 0 millimeters HO and 5 millimeters HO, preferably between 0.25 millimeters HO and 5 millimeters HO, and preferably between 0.5 millimeters HO and 5 millimeters HO. In other embodiments, the RTD of the hollow tubular cooling element is between 1 millimeter HO and 5 millimeters HO. In further embodiments, the RTD of the hollow tubular cooling element is between 0 millimeters HO and 2.5 millimeters HO, preferably between 0.25 millimeters HO and 2.5 millimeters HO, and more preferably between 0.5 millimeters HO and 2.5 millimeters HO. In a further embodiment, the RTD of the hollow tubular cooling element is between 0 millimeters HO and 2 millimeters HO, preferably between 0.25 millimeters HO and 2 millimeters HO, and more preferably between 0.5 millimeters HO and 2 millimeters HO. In one particularly preferred embodiment, the RTD of the hollow tubular cooling element is 0 millimeters HO.

[0187] In an aerosol-generating article according to the present invention, the overall RTD of the article depends essentially on the RTD of the rod and, optionally, the RTD of downstream and / or upstream elements, since the hollow tubular cooling element is substantially empty and therefore makes only a substantially small contribution to the overall RTD of the aerosol-generating article.

[0188] Therefore, the flow channels should not include any components that would impede the longitudinal air flow. It is preferred that the flow channels are substantially empty, and it is particularly preferred that the flow channels are empty.

[0189] As described in more detail herein, the aerosol-generating article may include ventilation zones at locations along the downstream section. In some embodiments, the aerosol-generating article may include ventilation zones at locations along the hollow tubular cooling element. These or any ventilation zones may extend through the peripheral wall of the hollow tubular cooling element. In this manner, fluid communication is established between the flow channels internally defined by the hollow tubular cooling element and the external environment. Ventilation zones are described further herein.

[0190] Preferably, the hollow tubular cooling element has a length of at least 20 millimeters. More preferably, the hollow tubular cooling element has a length of at least 30 millimeters. Optionally, the hollow tubular cooling element has a length of at least 40 millimeters. More preferably, the hollow tubular cooling element has a length of at least 45 millimeters.

[0191] Preferably, the hollow tubular cooling element has a length of less than 60 millimeters. More preferably, the hollow tubular cooling element has a length of less than 55 millimeters. More preferably, the hollow tubular cooling element has a length of less than 50 millimeters.

[0192] For example, the length of the hollow tubular cooling element may be 20 mm to 60 mm, or 30 mm to 60 mm, or 40 mm to 60 mm, or 45 mm to 60 mm. In other embodiments, the length of the hollow tubular cooling element may be 20 mm to 55 mm, or 30 mm to 55 mm, or 40 mm to 55 mm, or 45 mm to 55 mm. In other embodiments, the length of the hollow tubular cooling element may be 20 mm to 50 mm, or 30 mm to 50 mm, or 40 mm to 50 mm, or 45 mm to 50 mm.

[0193] The relatively long, hollow, tubular cooling element provides and defines a relatively long internal cavity within the aerosol-generating article and downstream of the rod of the aerosol-generating substrate. As discussed in this disclosure, providing an empty cavity downstream (preferably immediately downstream) of the aerosol-generating substrate enhances nucleation of aerosol particles generated by the substrate. Providing a relatively long cavity maximizes the benefits of such nucleation, thereby improving aerosol formation and cooling.

[0194] The ratio between the length of the hollow tubular cooling element and the length of the aerosol-generating substrate rod is preferably at least 1.0. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the aerosol-generating substrate rod is at least 1.25. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the aerosol-generating substrate rod is at least 1.5. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the aerosol-generating substrate rod is at least 1.75.

[0195] The ratio between the length of the hollow tubular cooling element and the length of the aerosol-generating substrate rod is preferably less than 3.5. Preferably, the ratio between the length of the hollow tubular cooling element and the length of the aerosol-generating substrate rod is less than 3.25. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the aerosol-generating substrate rod is less than 3.0. Even more preferably, the ratio between the length of the hollow tubular cooling element and the length of the aerosol-generating substrate rod is less than 2.75.

[0196] In some embodiments, the ratio between the length of the hollow tubular cooling element and the length of the rod of the aerosol-generating substrate is 1.0 to 3.5, preferably 1.25 to 3.5, more preferably 1.50 to 3.5, and even more preferably 1.75 to 3.5. In other embodiments, the ratio between the length of the hollow tubular cooling element and the length of the rod of the aerosol-generating substrate is 1.0 to 3.25, preferably 1.25 to 3.25, more preferably 1.50 to 3.25, and even more preferably 1.75 to 3.25. In further embodiments, the ratio between the length of the hollow tubular cooling element and the length of the rod of the aerosol-generating substrate is 1.0 to 3.0, preferably 1.25 to 3.0, more preferably 1.50 to 3.0, and even more preferably 1.75 to 3.0. In a further embodiment, the ratio between the length of the hollow tubular cooling element and the length of the rod of the aerosol-generating substrate is between 1.0 and 2.75, preferably between 1.25 and 2.75, more preferably between 1.50 and 2.75, even more preferably between 1.75 and 2.75.

[0197] The ratio between the length of the hollow tubular cooling element and the length of the downstream section may be less than 1. Preferably, the ratio between the length of the hollow tubular cooling element and the length of the downstream section may be less than 0.90. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the downstream section may be less than 0.85. Even more preferably, the ratio between the length of the hollow tubular cooling element and the length of the downstream section may be less than 0.80.

[0198] The ratio between the length of the hollow tubular cooling element and the length of the downstream section may be at least 0.35. Preferably, the ratio between the length of the hollow tubular cooling element and the length of the downstream section may be at least 0.45. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the downstream section may be at least 0.50. Even more preferably, the ratio between the length of the hollow tubular cooling element and the length of the downstream section may be at least 0.60.

[0199] In some embodiments, the ratio between the length of the hollow tubular cooling element and the length of the downstream section is 0.35 to 1, preferably 0.45 to 1, more preferably 0.50 to 1, and even more preferably 0.60 to 1. In other embodiments, the ratio between the length of the hollow tubular cooling element and the length of the downstream section is 0.35 to 0.90, preferably 0.45 to 0.90, more preferably 0.50 to 0.90, and even more preferably 0.60 to 0.90. In further embodiments, the ratio between the length of the hollow tubular cooling element and the length of the downstream section is 0.35 to 0.85, preferably 0.45 to 0.85, more preferably 0.50 to 0.85, and even more preferably 0.60 to 0.85. By way of example, the ratio between the length of the hollow tubular cooling element and the length of the downstream section may preferably be 0.75.

[0200] The ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article may be 0.80 or less. Preferably, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article may be 0.75 or less. More preferably, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article may be 0.70 or less. Even more preferably, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article may be 0.65 or less.

[0201] The ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article may be at least 0.40. Preferably, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article may be at least 0.45. More preferably, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article may be at least 0.50. Even more preferably, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article may be at least 0.6.

[0202] In some embodiments, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article is 0.40 to 0.80, preferably 0.45 to 0.80, more preferably 0.50 to 0.80, and even more preferably 0.60 to 0.80. In other embodiments, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article is 0.40 to 0.75, preferably 0.45 to 0.75, more preferably 0.50 to 0.75, and even more preferably 0.60 to 0.75. In further embodiments, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article is 0.40 to 0.70, preferably 0.45 to 0.70, more preferably 0.50 to 0.70, and even more preferably 0.60 to 0.70. In a further embodiment, the ratio between the length of the hollow tubular cooling element and the overall length of the aerosol-generating article is between 0.40 and 0.65, preferably between 0.45 and 0.65, more preferably between 0.50 and 0.65, and even more preferably between 0.60 and 0.65.

[0203] Providing a downstream section or hollow tubular cooling element with the ratios listed above maximizes the aerosol cooling and formation benefits of having a relatively long hollow tubular cooling element, while providing a sufficient amount of filtration for an aerosol-generating article that is configured to be heated rather than combusted. Additionally, providing a longer hollow tubular cooling element may advantageously reduce the effective RTD of the downstream section of the aerosol-generating article, which will be primarily defined by the RTD of the downstream filter segment.

[0204] The thickness of the peripheral wall of the hollow tubular cooling element (in other words, the wall thickness) may be at least 100 micrometers. The wall thickness of the hollow tubular cooling element may be at least 150 micrometers. The wall thickness of the hollow tubular cooling element may be at least 200 micrometers, preferably at least 250 micrometers, and even more preferably at least 500 micrometers (or 0.5 millimeters).

[0205] The wall thickness of the hollow tubular cooling element may be 2 millimeters or less, preferably 1.5 millimeters or less, and even more preferably 1.25 millimeters or less. The wall thickness of the hollow tubular cooling element may be 1 millimeter or less. The wall thickness of the hollow tubular cooling element may be 500 micrometers or less.

[0206] The wall thickness of the hollow tubular cooling element may be between 100 micrometers and 2 millimeters, preferably between 150 micrometers and 1.5 millimeters, and even more preferably between 200 micrometers and 1.25 millimeters.

[0207] The wall thickness of the hollow tubular cooling element may preferably be 250 micrometers (0.25 millimeters).

[0208] At the same time, keeping the peripheral wall thickness of the hollow tubular cooling element relatively low ensures that the overall internal volume of the hollow tubular cooling element (which is available for the aerosol to begin the nucleation process as soon as the aerosol components leave the aerosol-generating substrate rod) and the cross-sectional surface area of ​​the hollow tubular cooling element are effectively maximized, while at the same time ensuring that the hollow tubular cooling element has the structural strength necessary to provide some support to the aerosol-generating substrate rod as well as prevent collapse of the aerosol-generating article, and that the RTD of the hollow tubular cooling element is minimized. It is understood that a larger value for the cross-sectional surface area of ​​the hollow tubular cooling element's cavity is associated with a reduced velocity of the aerosol flow along the aerosol-generating article, which is also expected to favor aerosol nucleation. Furthermore, by utilizing hollow tubular cooling elements having a relatively small thickness, it may be believed that diffusion of the ventilation air can be substantially prevented before it contacts and mixes with the aerosol stream, which is also understood to be more favorable to the nucleation phenomenon. Indeed, by providing more controllably localized cooling of the volatilized species stream, it is possible to enhance the cooling effect on the formation of new aerosol particles.

[0209] The hollow tubular cooling element preferably has an outer diameter approximately equal to the outer diameter of the rod of the aerosol-generating substrate and the outer diameter of the aerosol-generating article.

[0210] 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 a preferred embodiment, the hollow tubular cooling element has an outer diameter of less than 7 millimeters.

[0211] The hollow tubular cooling element may have an inner diameter. Preferably, the hollow tubular cooling element may have 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.

[0212] 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.

[0213] Providing a hollow tubular cooling element with an inner diameter as set out above may advantageously provide the hollow tubular cooling element with sufficient stiffness and strength.

[0214] 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.

[0215] Providing a hollow tubular cooling element with an inner diameter as set out above may advantageously reduce the resistance to drawing the hollow tubular cooling element.

[0216] 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.

[0217] The ratio between the inner diameter of the hollow tubular cooling element and the outer diameter of the hollow tubular cooling element may be at least 0.8. For example, the ratio between the inner diameter of the hollow tubular cooling element and the outer diameter of the hollow tubular cooling element may be at least 0.85, at least 0.9, or at least 0.95.

[0218] The ratio between the inner diameter of the hollow tubular cooling element and the outer diameter of the hollow tubular cooling element may be 0.99 or less. For example, the ratio between the inner diameter of the hollow tubular cooling element and the outer diameter of the hollow tubular cooling element may be 0.98 or less.

[0219] The ratio between the inner diameter of the hollow tubular cooling element and the outer diameter of the hollow tubular cooling element may be 0.97.

[0220] Providing a relatively large inner diameter may advantageously reduce the resistance to drawing the hollow tubular cooling element and enhance cooling and nucleation of aerosol particles.

[0221] 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.

[0222] The hollow tubular cooling element may comprise a paper-based material. The hollow tubular cooling element may comprise at least one layer of paper. The paper may be a very stiff paper. The paper may be a crimped paper, such as crimped heat-resistant paper or crimped parchment paper.

[0223] Preferably, the hollow tubular cooling element may comprise cardboard. The hollow tubular cooling element may be a cardboard tube. The hollow tubular cooling element may be formed from cardboard. Advantageously, cardboard is a cost-effective material that provides a balance between being deformable to provide ease of insertion of an item into the aerosol generating device and being sufficiently rigid to provide proper engagement of the item with the interior of the device. Thus, a cardboard tube may provide suitable resistance to deformation or compression during use.

[0224] The hollow tubular cooling element may be a paper tube. The hollow tubular cooling element may be a tube formed from spirally wound paper. The hollow tubular cooling element may be formed from multiple layers of paper. The paper may 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.

[0225] The hollow tubular cooling element may comprise a polymeric material. For example, the hollow tubular cooling element may comprise a polymeric film. The polymeric film may comprise a cellulose film. The hollow tubular cooling element may comprise low-density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers. The hollow tube may comprise cellulose acetate tow.

[0226] When the hollow tubular cooling element comprises cellulose acetate tow, the cellulose acetate tow may have a denier per filament of 2 to 4 and a total denier of 25 to 40.

[0227] In some embodiments, aerosol-generating articles according to the present invention may include a ventilation zone at a location along the downstream section. More particularly, in those embodiments in which the downstream section comprises a hollow tubular cooling element, the ventilation zone may be provided at a location along the hollow tubular cooling element. Alternatively, in those embodiments in which the downstream section comprises a downstream hollow tubular element, the ventilation zone may be provided at a location along the downstream hollow tubular element.

[0228] In this way, a vented cavity is provided downstream of the rod of the aerosol-generating substrate, which offers several potential technical advantages.

[0229] First, the inventors have found that one such vented hollow tubular cooling element provides particularly efficient cooling of the aerosol. Therefore, satisfactory cooling of the aerosol can be achieved even with a relatively short downstream section. This is particularly desirable because it allows the aerosol-generating substrate (and particularly those containing tobacco) to be heated rather than burned, thereby providing an aerosol-generating article that combines satisfactory aerosol delivery with efficient cooling of the aerosol to a temperature desirable for the consumer.

[0230] Second, the inventors have surprisingly found that such rapid cooling of volatile species released upon heating of the aerosol-generating substrate promotes and enhances nucleation of aerosol particles. This effect is particularly felt when the ventilation zone is disposed at a precisely defined position along the length of the hollow tubular cooling element relative to other components of the aerosol-generating article, as explained in more detail below. Indeed, the inventors have surprisingly found that the favorable effect of enhanced nucleation can significantly counteract the potentially undesirable effect of dilution induced by the introduction of ventilation air.

[0231] The distance between the ventilation zone and the upstream end of the upstream element may be at least 25 millimeters. As used herein, the term "distance between the ventilation zone and another element or portion of the aerosol-generating article" refers to a distance measurement in the longitudinal direction, i.e., extending along or parallel to the cylindrical axis of the aerosol-generating article.

[0232] Preferably, the distance between the ventilation zone and the upstream end of the upstream element is at least 26 millimeters. More preferably, the distance between the ventilation zone and the upstream end of the upstream element is at least 27 millimeters.

[0233] The distance between the ventilation zone and the upstream end of the upstream element can be 34 millimeters or less. Preferably, the distance between the ventilation zone and the upstream end of the upstream element is 33 millimeters or less. More preferably, the distance between the ventilation zone and the upstream end of the upstream element is 31 millimeters or less.

[0234] In some embodiments, the distance between the ventilation zone and the upstream end of the upstream element is between 25 millimeters and 34 millimeters, preferably between 26 millimeters and 34 millimeters, and more preferably between 27 millimeters and 34 millimeters.

[0235] In other embodiments, the distance between the ventilation zone and the upstream end of the upstream element is between 25 millimeters and 33 millimeters, preferably between 26 millimeters and 33 millimeters, and more preferably between 27 millimeters and 33 millimeters.

[0236] In a further embodiment, the distance between the ventilation zone and the upstream end of the upstream element is between 25 millimeters and 31 millimeters, preferably between 26 millimeters and 31 millimeters, and more preferably between 27 millimeters and 31 millimeters.

[0237] In some particularly preferred embodiments, the distance between the ventilation zone and the upstream end of the upstream element is between 28 millimeters and 30 millimeters.

[0238] It has been found that aerosol-generating articles with ventilation zones located along the hollow tubular cooling element at distances from the upstream end of the upstream element within the above ranges offer several benefits.

[0239] First, such articles have been observed to provide consumers with particularly satisfactory aerosol delivery, especially when the aerosol-generating substrate comprises tobacco.

[0240] Without wishing to be bound by theory, it is understood that the intense cooling caused by the ambient air drawn into the cavity of the hollow tubular cooling element in the ventilation zone accelerates the condensation of droplets of aerosol former (e.g., glycerin) released from the aerosol-generating substrate upon heating. Volatilized nicotine and organic acids, also released from the tobacco substrate, then accumulate on the newly formed droplets of aerosol former and subsequently combine into nicotine salts. Thus, the overall ratio of aerosol particle phase to aerosol vapor phase can be enhanced compared to existing aerosol-generating articles.

[0241] Positioning the ventilation zone at such a distance from the upstream end of the upstream element advantageously reduces the flight time of the volatile nicotine particles before they reach the droplets of the aerosol former. At the same time, such positioning of the ventilation zone relative to the upstream end of the upstream element ensures that there is sufficient time and space for nicotine accumulation and nicotine salt formation to occur at a significant rate before the aerosol stream reaches the consumer's mouth.

[0242] A ventilation zone typically includes a plurality of perforations through the circumferential wall of the hollow tubular cooling element. Preferably, the ventilation zone 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 between 8 and 30 perforations.

[0243] Aerosol-generating articles according to the present invention may have a breathability level of at least 2 percent.

[0244] The term "ventilation level" is used throughout this specification to mean the volume ratio between the airflow entering the aerosol-generating article via the ventilation zone (ventilation airflow) and the sum of the aerosol airflow and the ventilation airflow. The greater the ventilation level, the greater the dilution of the aerosol stream delivered to the consumer. The aerosol-generating article preferably has a ventilation level of at least 5 percent, more preferably at least 10 percent, and even more preferably at least 12 percent or at least 15 percent.

[0245] Aerosol-generating articles according to the present invention may have a breathability level of up to 90 percent. Preferably, aerosol-generating articles according to the present invention have a breathability level of 80 percent or less, more preferably 70 percent or less, even more preferably 60 percent or less, and most preferably 50 percent or less.

[0246] Thus, aerosol-generating articles according to the present invention may have a ventilation level of 2 to 90 percent, preferably 5 to 90 percent, more preferably 10 to 90 percent, and even more preferably 15 to 90 percent. Aerosol-generating articles according to the present invention may have a ventilation level of 2 to 80 percent, preferably 5 to 80 percent, more preferably 10 to 80 percent, and even more preferably 15 to 80 percent. Aerosol-generating articles according to the present invention may have a ventilation level of 2 to 70 percent, preferably 5 to 70 percent, more preferably 10 to 70 percent, and even more preferably 15 to 70 percent. Aerosol-generating articles according to the present invention may have a ventilation level of 2 to 60 percent, preferably 5 to 60 percent, more preferably 10 to 60 percent, and even more preferably 15 to 60 percent. Aerosol-generating articles according to the present invention may have a ventilation level of 2 to 50 percent, preferably 5 to 50 percent, more preferably 10 to 50 percent, and even more preferably 15 to 50 percent. The aerosol-generating article preferably has a breathability level of 30 percent or less, preferably 25 percent or less, more preferably 20 percent or less, and even more preferably 18 percent or less.

[0247] In some embodiments, the aerosol-generating article has a ventilation level of 10 percent to 30 percent, preferably 12 percent to 30 percent, and more preferably 15 percent to 30 percent. In other embodiments, the aerosol-generating article has a ventilation level of 10 percent to 25 percent, preferably 12 percent to 25 percent, and more preferably 15 percent to 25 percent. In further embodiments, the aerosol-generating article has a ventilation level of 10 percent to 20 percent, preferably 12 percent to 20 percent, and more preferably 15 percent to 20 percent. In particularly preferred embodiments, the aerosol-generating article has a ventilation level of 10 percent to 18 percent, preferably 12 percent to 18 percent, and more preferably 15 percent to 18 percent.

[0248] Without wishing to be bound by theory, the inventors have found that the temperature reduction caused by admitting cooler outside air through the ventilation zone into the hollow tubular cooling element can have a beneficial effect on aerosol particle nucleation and growth.

[0249] The formation of aerosols from gaseous mixtures containing various chemical species depends on a delicate interplay between nucleation, evaporation, condensation, and even fusion, which accounts for changes in vapor concentration, temperature, and velocity fields. The so-called classical nucleation theory is based on the assumption that a fraction of molecules in the gas phase are large enough to remain coherent for a long time with a sufficient probability (e.g., a 50 / 50 chance). These molecules represent a certain kind of critical, threshold molecular cluster within the transient molecular aggregates, meaning that smaller molecular clusters generally tend to break down into the gas phase rather quickly, while larger clusters generally tend to grow. These critical clusters are identified as primary nucleation cores from which droplets are expected to grow due to the condensation of molecules from the vapor. It is assumed that freshly nucleated, raw droplets emerge with a certain original diameter and may subsequently grow by several orders of magnitude. This may be facilitated and enhanced by the rapid cooling of the surrounding vapor, which induces condensation. In this regard, it is helpful to remember that evaporation and condensation are two aspects of one and the same mechanism: gas-liquid mass transfer. Evaporation involves the net mass transfer from the droplets to the gas phase, while condensation is the net mass transfer from the gas phase to the droplet phase. Evaporation (or condensation) causes the droplets to shrink (or grow), but the number of droplets remains the same.

[0250] In this scenario (when the scenario is further complicated by fusion phenomena), the temperature and rate of cooling may play an important role in determining how the system responds. In general, because the nucleation process is typically nonlinear, different cooling rates may lead to significantly different temperature behaviors with respect to the formation of the liquid phase (droplets). Without wishing to be bound by theory, it is hypothesized that cooling can cause a rapid increase in the number of condensed droplets, followed by a short-term, strong increase in this growth (nucleation burst). This nucleation burst appears to be more pronounced at lower temperatures. Furthermore, it appears that a faster cooling rate may favor the onset of early nucleation. In contrast, a decrease in the cooling rate appears to have a favorable effect on the final size that the aerosol droplets ultimately reach.

[0251] Thus, the rapid cooling induced by admitting ambient air through the ventilation zone into the hollow tubular cooling element can be used to favor the favorable nucleation and growth of aerosol droplets. At the same time, however, admitting ambient air into the hollow tubular cooling element has the direct disadvantage of diluting the aerosol stream delivered to the consumer.

[0252] The inventors have surprisingly found that the favorable effect of enhanced nucleation promoted by the rapid cooling induced by the introduction of ventilation air into the article can significantly counteract the undesirable effects of dilution. Thus, satisfactory values ​​of aerosol delivery are consistently achieved using aerosol-generating articles according to the present invention.

[0253] The inventors have also surprisingly found that the dilution effect on the aerosol, which can be assessed by measurement, specifically the effect on the delivery of the aerosol former (e.g., glycerol) contained in the aerosol-generating substrate, is advantageously minimized when the aeration level is within the above-mentioned ranges.

[0254] Specifically, aeration levels of 10 percent to 20 percent, and even more preferably 12 to 18 percent, have been found to lead to particularly satisfactory values ​​of glycerol delivery.

[0255] Because the vented hollow tubular cooling element does not substantially contribute to the overall RTD of the aerosol-generating article, in an aerosol-generating article according to the present invention, the overall RTD of the article can be advantageously fine-tuned by adjusting the length and density of the rods of the aerosol-generating substrate, or the length, and optionally the length and density, of the segment of filtration material forming part of the downstream section (e.g., downstream filter segment, etc.), or the length and density of the segment of filtration material provided upstream of the aerosol-generating substrate. Therefore, aerosol-generating articles having a predetermined RTD can be consistently and precisely manufactured, thereby providing a satisfactory level of RTD for the consumer, even in the presence of ventilation.

[0256] The distance between the ventilation zone and the downstream end of the rod of the aerosol-generating substrate may be at least 4 millimeters, or at least 6 millimeters, or at least 8 millimeters. Preferably, the distance between the ventilation zone and the downstream end of the rod of the aerosol-generating substrate is at least 9 millimeters. More preferably, the distance between the ventilation zone and the downstream end of the rod of the aerosol-generating substrate is at least 10 millimeters.

[0257] Preferably, the distance between the ventilation zone and the downstream end of the aerosol-generating substrate rod is less than 17 millimeters. More preferably, the distance between the ventilation zone and the downstream end of the aerosol-generating substrate rod is less than 16 millimeters. Even more preferably, the distance between the ventilation zone and the downstream end of the aerosol-generating substrate rod is less than 16 millimeters. In a particularly preferred embodiment, the distance between the ventilation zone and the downstream end of the aerosol-generating substrate rod is less than 15 millimeters.

[0258] In some embodiments, the distance between the ventilation zone and the downstream end of the rod of the aerosol-generating substrate is 4 to 17 millimeters, preferably 7 to 17 millimeters, and more preferably 10 to 17 millimeters. In other embodiments, the distance between the ventilation zone and the downstream end of the rod of the aerosol-generating substrate is 8 to 16 millimeters, preferably 9 to 16 millimeters, and more preferably 10 to 16 millimeters. In further embodiments, the distance between the ventilation zone and the downstream end of the rod of the aerosol-generating substrate is 8 to 15 millimeters, preferably 9 to 15 millimeters, and more preferably 10 to 15 millimeters. By way of example, the distance between the ventilation zone and the downstream end of the rod of the aerosol-generating substrate is 10 to 14 millimeters, preferably 10 to 13 millimeters, and more preferably 10 to 12 millimeters.

[0259] Locating the ventilation zone within the above-mentioned ranges from the downstream end of the rod of the aerosol-generating substrate has the advantage that, in use, it generally ensures that when the aerosol-generating article is inserted into the heating device, the ventilation zone is just outside the heating device, reducing the risk of the ventilation zone being accidentally blocked by the user's lips or hands. Additionally, it has been found that locating the ventilation zone a short distance within the above-mentioned ranges from the downstream end of the rod of the aerosol-generating substrate may advantageously enhance nucleation and aerosol formation and delivery.

[0260] The distance between the ventilation zone and the downstream end of the hollow tubular cooling element may be at least 3 millimeters. Preferably, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is at least 5 millimeters. More preferably, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is at least 7 millimeters.

[0261] Preferably, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is 14 millimeters or less. More preferably, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is 12 millimeters or less. Even more preferably, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is 10 millimeters or less.

[0262] In some embodiments, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is between 3 millimeters and 14 millimeters, preferably between 5 millimeters and 14 millimeters, and more preferably between 7 millimeters and 14 millimeters. In further embodiments, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is between 3 millimeters and 12 millimeters, preferably between 5 millimeters and 12 millimeters, and more preferably between 7 millimeters and 12 millimeters. In other embodiments, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is between 3 millimeters and 10 millimeters, preferably between 5 millimeters and 10 millimeters, and more preferably between 7 millimeters and 10 millimeters.

[0263] Locating the ventilation zone within the aforementioned ranges away from the downstream end of the hollow tubular cooling element has the advantage of generally ensuring that the ventilation zone is just outside the heating device when the aerosol-generating article is inserted into the heating device during use, reducing the risk of the ventilation zone being accidentally blocked by a user's lips or hands. Additionally, it has been found that locating the ventilation zone within the aforementioned ranges away from the downstream end of the hollow tubular cooling element can advantageously lead to relatively more uniform aerosol formation and delivery.

[0264] The distance between the ventilation zone and the downstream end of the aerosol-generating article may be at least 10 millimeters. Preferably, the distance between the ventilation zone and the downstream end of the aerosol-generating article is at least 12 millimeters. More preferably, the distance between the ventilation zone and the downstream end of the aerosol-generating article is at least 15 millimeters.

[0265] Preferably, the distance between the ventilation zone and the downstream end of the aerosol-generating article is 21 millimeters or less. More preferably, the distance between the ventilation zone and the downstream end of the aerosol-generating article is 19 millimeters or less. Even more preferably, the distance between the ventilation zone and the downstream end of the aerosol-generating article is 17 millimeters or less.

[0266] In some embodiments, the distance between the ventilation zone and the downstream end of the aerosol-generating article is between 10 millimeters and 21 millimeters, preferably between 12 millimeters and 21 millimeters, and more preferably between 15 millimeters and 21 millimeters. In further embodiments, the distance between the ventilation zone and the downstream end of the aerosol-generating article is between 10 millimeters and 19 millimeters, preferably between 12 millimeters and 19 millimeters, and more preferably between 15 millimeters and 19 millimeters. In other embodiments, the distance between the ventilation zone and the downstream end of the aerosol-generating article is between 10 millimeters and 17 millimeters, preferably between 12 millimeters and 17 millimeters, and more preferably between 15 millimeters and 17 millimeters.

[0267] Locating the ventilation zone within the aforementioned distance from the downstream end of the aerosol-generating article has the advantage that, in use, when the aerosol-generating article is partially received within the heating device, the portion of the aerosol-generating article extending outside the heating device is long enough to allow a consumer to comfortably hold the article between their lips, reducing the risk of the ventilation zone being accidentally blocked by the user's lips or hands. At the same time, evidence suggests that the longer length of the portion of the aerosol-generating article extending outside the heating device may make it easier to inadvertently and undesirably bend the aerosol-generating article, which may impair aerosol delivery or, generally, the intended use of the aerosol-generating article.

[0268] As discussed in this disclosure, the downstream section may include 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.

[0269] The downstream filter segment may be located downstream of the hollow tubular cooling element, as described above, and may extend between the hollow tubular cooling element and the downstream end of the aerosol-generating article.

[0270] 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.

[0271] The downstream filter segment is preferably formed of a fibrous filter material. The fibrous filter material may be for filtering aerosols generated from an aerosol-generating 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.

[0272] 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 end-to-end abutting relationship with one another.

[0273] The downstream filter segment may optionally include a flavorant, which may be provided in any suitable form, for example, the downstream filter segment may comprise one or more capsules, beads, or granules of flavorant, or one or more flavor-loaded threads or filaments.

[0274] The downstream filter segment preferably has a low particle filtration efficiency.

[0275] The downstream filter segment is preferably surrounded by 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.

[0276] The downstream filter segment is preferably connected to one or more of the adjacent upstream components of the aerosol-generating article by a tipping wrapper.

[0277] The downstream filter segment preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article. The diameter of the downstream filter segment may be substantially the same as the outer diameter of the hollow tubular cooling element.

[0278] The outer diameter of the downstream filter segment may be between 5 millimeters and 10 millimeters. The diameter of the downstream filter segment may be between 5.5 millimeters and 9 millimeters. The diameter of the downstream filter segment may be between 6 millimeters and 8 millimeters. In a preferred embodiment, the diameter of the downstream filter segment is less than 7 millimeters.

[0279] Unless otherwise specified, the resistance to draw (RTD) of a component or aerosol-generating article is measured in accordance with ISO 6565-2015. 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." These terms generally refer to measurements in accordance with ISO 6565-2015 being performed successfully under a test temperature of 22 degrees Celsius, a pressure of 101 kPa (approximately 760 Torr), and 60% relative humidity with a volumetric flow rate of 17.5 milliliters per second at the output or downstream end of the measured component. Smoking conditions and smoking machine specifications are provided in ISO Standard 3308 (ISO 3308:2000). Conditioning and testing atmospheres are provided in ISO Standard 3402 (ISO 3402:1999).

[0280] The resistance to draw (RTD) of the downstream section may be at least 0 millimeters of H2O. The RTD of the downstream section may be at least 3 millimeters of H2O. The RTD of the downstream section may be at least 6 millimeters of H2O.

[0281] The RTD of the downstream section may be 12 millimeters H2O or less. The RTD of the downstream section may be 11 millimeters H2O or less. The RTD of the downstream section may be 10 millimeters H2O or less.

[0282] The withdrawal resistance of the downstream section may be equal to or greater than 0 mm H2O and less than 12 mm H2O. Preferably, the withdrawal resistance of the downstream section may be equal to or greater than 3 mm H2O and less than 12 mm H2O. The withdrawal resistance of the downstream section may be equal to or greater than 0 mm H2O and less than 11 mm H2O. Even more preferably, the withdrawal resistance of the downstream section may be equal to or greater than 3 mm H2O and less than 11 mm H2O. Even more preferably, the withdrawal resistance of the downstream section may be equal to or greater than 6 mm H2O and less than 10 mm H2O. Preferably, the withdrawal resistance of the downstream section may be 8 mm H2O.

[0283] The resistance to draw (RTD) characteristics of the downstream section may be entirely or predominantly attributable to the RTD characteristics of the downstream filter segments of the downstream section. In other words, the RTD of the downstream filter segments of the downstream section may completely define the RTD of the downstream section.

[0284] The resistance to draw (RTD) of the downstream filter segment may be at least 0 millimeters of H2O. The RTD of the downstream filter segment may be at least 3 millimeters of H2O. The RTD of the downstream filter segment may be at least 6 millimeters of H2O.

[0285] The RTD of the downstream filter segment may be less than or equal to 12 millimeters H2O. The RTD of the downstream filter segment may be less than or equal to 11 millimeters H2O. The RTD of the downstream filter segment may be less than or equal to 10 millimeters H2O.

[0286] The resistance to withdrawal of the downstream filter segment may be 0 millimeters of H2O or more and less than 12 millimeters of H2O. Preferably, the resistance to withdrawal of the downstream filter segment may be 3 millimeters of H2O or more and less than 12 millimeters of H2O. The resistance to withdrawal of the downstream filter segment may be 0 millimeters of H2O or more and less than 11 millimeters of H2O. Even more preferably, the resistance to withdrawal of the downstream filter segment may be 3 millimeters of H2O or more and less than 11 millimeters of H2O. Even more preferably, the resistance to withdrawal of the downstream filter segment may be 6 millimeters of H2O or more and less than 10 millimeters of H2O. Preferably, the resistance to withdrawal of the downstream filter segment may be 8 millimeters of H2O.

[0287] As described above, the downstream filter segment may be formed from a fibrous material. The downstream filter segment may be formed from a porous material. The downstream filter segment may be formed from a biodegradable material. The downstream filter segment may be formed from 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 12 denier fibers per filament.

[0288] The downstream filter segment may be formed of a polylactic acid-based material. The downstream filter segment may be formed of a bioplastic material, preferably a starch-based bioplastic material. The downstream filter segment may be fabricated by injection molding or extrusion. Bioplastic-based materials are advantageous because they can provide a downstream filter segment structure that is simple and inexpensive to manufacture due to a specific complex cross-sectional profile that may include multiple relatively large airflow channels extending through the downstream filter segment material, providing favorable RTD characteristics.

[0289] The downstream filter segment can be formed from a sheet of suitable material that has been crimped, pleated, gathered, woven, or folded into elements that define a plurality of longitudinally extending channels. Such a sheet of suitable material can be formed from paper, cardboard, a polymer such as polylactic acid, or any other cellulosic, paper, or bioplastic-based material. The cross-sectional profile of such a downstream filter segment can exhibit randomly oriented channels.

[0290] The downstream filter segment may be formed in any other suitable manner. For example, the downstream filter segment may be formed from a bundle of longitudinally extending tubes. The longitudinally extending tubes may be formed from polylactic acid. The downstream filter segment may be formed by extrusion, molding, lamination, injection, or chopping of a suitable material. Therefore, it is preferable that there is a low pressure drop (or RTD) from the upstream end of the downstream filter segment to the downstream end of the downstream filter segment.

[0291] The length of the downstream filter segment may be at least 5 millimeters. The length of the downstream filter segment may be at least 10 millimeters. The length of the downstream filter segment may be less than 25 millimeters. The length of the downstream filter segment may be less than 20 millimeters. For example, the length of the downstream filter segment may be between 5 millimeters and 25 millimeters, or between 10 millimeters and 25 millimeters, or between 5 millimeters and 20 millimeters, or between 10 millimeters and 20 millimeters.

[0292] The ratio between the length of the downstream filter segment and the length of the downstream section may be 0.55 or less. Preferably, the ratio between the length of the downstream filter segment and the length of the downstream section may be 0.45 or less. More preferably, the ratio between the length of the downstream filter segment and the length of the downstream section may be 0.35 or less. Even more preferably, the ratio between the length of the downstream filter segment and the length of the downstream section may be 0.25 or less.

[0293] The ratio between the length of the downstream filter segment and the length of the downstream section may be at least 0.05. Preferably, the ratio between the length of the downstream filter segment and the length of the downstream section may be at least 0.10. More preferably, the ratio between the length of the downstream filter segment and the length of the downstream section may be at least 0.15. Even more preferably, the ratio between the length of the downstream filter segment and the length of the downstream section may be at least 0.20.

[0294] In some embodiments, the ratio between the length of the downstream filter segment and the length of the downstream section is 0.05 to 0.55, preferably 0.10 to 0.55, more preferably 0.15 to 0.55, and even more preferably 0.20 to 0.55. In other embodiments, the ratio between the length of the downstream filter segment and the length of the downstream section is 0.05 to 0.45, preferably 0.10 to 0.45, more preferably 0.15 to 0.45, and even more preferably 0.20 to 0.45. In further embodiments, the ratio between the length of the downstream filter segment and the length of the downstream section is 0.05 to 0.35, preferably 0.10 to 0.35, more preferably 0.15 to 0.35, and even more preferably 0.20 to 0.35. By way of example, the ratio between the length of the downstream filter segment and the length of the downstream section may preferably be 0.20 to 0.25, and even more preferably the ratio between the length of the downstream filter segment and the length of the downstream section may be 0.25.

[0295] The ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be 0.40 or less. Preferably, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be 0.30 or less. More preferably, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be 0.25 or less. Even more preferably, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be 0.20 or less.

[0296] The ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be at least 0.05. Preferably, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be at least 0.07. More preferably, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be at least 0.10. Even more preferably, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be at least 0.15.

[0297] In some embodiments, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article is 0.05 to 0.40, preferably 0.07 to 0.40, more preferably 0.10 to 0.40, and even more preferably 0.15 to 0.40. In other embodiments, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article is 0.05 to 0.30, preferably 0.07 to 0.30, more preferably 0.10 to 0.30, and even more preferably 0.15 to 0.30. In further embodiments, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article is 0.05 to 0.25, preferably 0.07 to 0.25, more preferably 0.10 to 0.25, and even more preferably 0.15 to 0.25. For example, the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be 0.15 to 0.20, and more preferably the ratio between the length of the downstream filter segment and the overall length of the aerosol-generating article may be 0.16.

[0298] In embodiments in which the downstream section comprises a hollow tubular cooling element and a downstream filter segment, the ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be at least 1.25. In other words, the length of the hollow tubular cooling element may be equal to 125% of the length of the downstream filter segment. The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be at least 1.5. The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be at least 2.

[0299] The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be equal to or less than 8.5. The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be equal to or less than 6. The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be equal to or less than 4.

[0300] The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be 1.25 to 8.5. The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be 1.5 to 6. The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be 2 to 4.

[0301] In certain preferred embodiments, the downstream section may include a ventilation zone downstream of the downstream filter segment. In one example, a ventilation zone downstream of the downstream filter segment may be provided in place of a ventilation zone along the hollow tubular cooling element. In another example, a ventilation zone downstream of the downstream filter segment may be provided in addition to a ventilation zone above the hollow tubular cooling element.

[0302] The ventilation zone downstream of the filter segment may include a plurality of perforations. Preferably, the ventilation zone downstream of the filter segment includes at least one circumferential row of perforations. In some embodiments, the ventilation zone downstream of the filter segment 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 between 8 and 30 perforations.

[0303] The downstream section may further comprise one or more additional hollow tubular elements.

[0304] 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 rod of the aerosol-generating substrate. Preferably, the hollow tubular support element abuts the upstream end of the hollow tubular cooling element. Preferably, the hollow tubular support element and the hollow tubular cooling element are adjacent to each other and together provide a hollow tubular section within the downstream section.

[0305] 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, crimped paper (such as crimped heat-resistant paper or crimped parchment paper), and polymeric materials (such as low-density polyethylene (LDPE)). In a preferred embodiment, the support element is formed from cellulose acetate. Other suitable materials include polyhydroxyalkanoate (PHA) fibers. In a preferred embodiment, the hollow tubular support element comprises a hollow acetate tube.

[0306] The hollow tubular support element preferably has an outer diameter approximately equal to the outer diameter of the rod of the aerosol-generating substrate and the outer diameter of the aerosol-generating article.

[0307] The hollow tubular support element may have an outer diameter of 5 millimeters to 10 millimeters, e.g., 5.5 millimeters to 9 millimeters, or 6 millimeters to 8 millimeters. In a preferred embodiment, the hollow tubular support element has an outer diameter of less than 7 millimeters.

[0308] 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.

[0309] 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, and more preferably at least about 7 millimeters.

[0310] 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.

[0311] In some embodiments, the support element has a length of 5 mm to 15 mm, preferably 6 mm to 15 mm, and more preferably 7 mm to 15 mm. In other embodiments, the support element has a length of 5 mm to 12 mm, preferably 6 mm to 12 mm, and more preferably 7 mm to 12 mm. In further embodiments, the support element has a length of 5 mm to 10 mm, preferably 6 mm to 10 mm, and more preferably 7 mm to 10 mm.

[0312] Preferably, the hollow tubular section has a length of at least 20 millimeters. More preferably, the hollow tubular section has a length of at least 30 millimeters. Optionally, the hollow tubular section has a length of at least 40 millimeters. More preferably, the hollow tubular section has a length of at least 45 millimeters.

[0313] Preferably, the hollow tubular section has a length of less than 60 millimeters. More preferably, the hollow tubular section has a length of less than 55 millimeters. More preferably, the hollow tubular section has a length of less than 50 millimeters.

[0314] For example, the length of the hollow tubular section may be 20 mm to 60 mm, or 30 mm to 60 mm, or 40 mm to 60 mm, or 45 mm to 60 mm. In other embodiments, the length of the hollow tubular section may be 20 mm to 55 mm, or 30 mm to 55 mm, or 40 mm to 55 mm, or 45 mm to 55 mm. In other embodiments, the length of the hollow tubular section may be 20 mm to 50 mm, or 30 mm to 50 mm, or 40 mm to 50 mm, or 45 mm to 50 mm.

[0315] Alternatively 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,

[0316] 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. Thus, the downstream hollow tubular element is preferably located downstream of the downstream filter segment, and the downstream hollow tubular element abuts the downstream end of the downstream filter segment.

[0317] 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. In certain embodiments, additional downstream hollow tubular elements may be provided so that the downstream section comprises two adjacent downstream hollow tubular elements downstream of the downstream filter segment.

[0318] Preferably, the RTD of the downstream hollow tubular element is 10 millimeters HO or less. More preferably, the RTD of the downstream hollow tubular element is 5 millimeters HO or less. Even more preferably, the RTD of the downstream hollow tubular element is 2.5 millimeters HO or less. Even more preferably, the RTD of the downstream hollow tubular element is 2 millimeters HO or less. Even more preferably, the RTD of the downstream hollow tubular element is 1 millimeter HO or less.

[0319] The RTD of the downstream hollow tubular element may be at least 0 millimeters H2O, or at least 0.25 millimeters H2O, or at least 0.5 millimeters H2O, or at least 1 millimeter H2O.

[0320] In some preferred embodiments, the RTD of the downstream hollow tubular element is between 0 millimeters HO and 10 millimeters HO, preferably between 0.25 millimeters HO and 10 millimeters HO, and preferably between 0.5 millimeters HO and 10 millimeters HO. In other embodiments, the RTD of the downstream hollow tubular element is between 0 millimeters HO and 5 millimeters HO, preferably between 0.25 millimeters HO and 5 millimeters HO, and preferably between 0.5 millimeters HO and 5 millimeters HO. In other embodiments, the RTD of the downstream hollow tubular element is between 1 millimeter HO and 5 millimeters HO. In further embodiments, the RTD of the downstream hollow tubular element is between 0 millimeters HO and 2.5 millimeters HO, preferably between 0.25 millimeters HO and 2.5 millimeters HO, and more preferably between 0.5 millimeters HO and 2.5 millimeters HO. In a further embodiment, the RTD of the downstream hollow tubular element is between 0 millimeters HO and 2 millimeters HO, preferably between 0.25 millimeters HO and 2 millimeters HO, and more preferably between 0.5 millimeters HO and 2 millimeters HO. In a particularly preferred embodiment, the RTD of the downstream hollow tubular element is 0 millimeters HO.

[0321] Therefore, the air flow channel of the downstream hollow tubular element should not contain any components that would impede the longitudinal air flow. It is preferred that the flow channel is substantially empty, and it is particularly preferred that the flow channel is empty.

[0322] Preferably, the length of the downstream hollow tubular element is at least 3 millimeters. More preferably, the length of the downstream hollow tubular element is at least 4 millimeters. The length of the downstream hollow tubular element may be at least 5 millimeters. More preferably, the length of the downstream hollow tubular element is at least 6 millimeters.

[0323] Preferably, the length of the downstream hollow tubular element is less than 20 millimeters. More preferably, the length of the downstream hollow tubular element is less than 15 millimeters. More preferably, the length of the downstream hollow tubular element is less than 12 millimeters. More preferably, the length of the downstream hollow tubular element is less than 10 millimeters.

[0324] For example, the length of the downstream hollow tubular element may be 3 mm to 20 mm, or 4 mm to 20 mm, or 5 mm to 20 mm, or 6 mm to 20 mm. In other embodiments, the length of the downstream hollow tubular element may be 3 mm to 15 mm, 4 mm to 15 mm, 5 mm to 15 mm, or 6 mm to 15 mm. In other embodiments, the length of the downstream hollow tubular element may be 3 mm to 12 mm, 4 mm to 12 mm, or 5 mm to 12 mm, or 6 mm to 12 mm. In other embodiments, the length of the downstream hollow tubular element may be 3 mm to 10 mm, or 4 mm to 10 mm, or 5 mm to 10 mm, or 6 mm to 10 mm.

[0325] If a downstream hollow tubular element is included in the downstream section, the combined length of the hollow tubular cooling element and the downstream hollow tubular element(s) is preferably at least 20 millimeters. This corresponds to the sum of the length of the hollow tubular cooling element and the length of the downstream hollow tubular element(s), not taking into account the length of any components provided in between. More preferably, the combined length is at least 30 millimeters. The combined length may be at least 40 millimeters. More preferably, the combined length is at least 45 millimeters.

[0326] Preferably, the combined length of the hollow tubular cooling element and the downstream hollow tubular element(s) is less than 60 millimeters. More preferably, the combined length is less than 55 millimeters. More preferably, the combined length is less than 50 millimeters.

[0327] For example, the combined length of the hollow tubular cooling element and the downstream hollow tubular element (or elements) may be 20 mm to 60 mm, or 30 mm to 60 mm, or 40 mm to 60 mm, or 45 mm to 60 mm. In other embodiments, the combined length may be 20 mm to 55 mm, or 30 mm to 55 mm, or 40 mm to 55 mm, or 45 mm to 55 mm. In other embodiments, the combined length may be 20 mm to 50 mm, or 30 mm to 50 mm, or 40 mm to 50 mm, or 45 mm to 50 mm.

[0328] By providing a combined length within the ranges discussed above, the overall length of the hollow tubular elements in the downstream section is relatively long, with the benefits discussed above regarding the length of the hollow tubular cooling elements.

[0329] 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.

[0330] The downstream hollow tubular element may comprise a paper-based material. The downstream hollow tubular element may comprise at least one paper layer. The paper may be a very stiff paper. The paper may be a crimped paper, such as crimped heat-resistant paper or crimped parchment paper.

[0331] The downstream hollow tubular element may comprise cardboard.The downstream hollow tubular element may be a cardboard tube.

[0332] 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 multiple 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.

[0333] The downstream hollow tubular element may comprise a polymeric material. For example, the downstream hollow tubular element may comprise a polymeric film. The polymeric film may comprise a cellulose film. The downstream hollow tubular element may comprise low-density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers. Preferably, the downstream hollow tubular element comprises cellulose acetate tow. For example, in a preferred embodiment, the downstream hollow tubular element comprises a hollow acetate tube.

[0334] When the downstream hollow tubular element comprises cellulose acetate tow, the cellulose acetate tow may have a denier per filament of 2 to 4 and a total denier of 25 to 40.

[0335] If the downstream section further comprises an additional downstream hollow tubular element as described above, the additional downstream hollow tubular element may be formed from the same material as the downstream hollow tubular element or from a different material.

[0336] In certain preferred embodiments, the downstream section may include a ventilation zone at the location of the downstream hollow tubular element. In one example, this ventilation zone at the location of the downstream hollow tubular element may be provided in place of the ventilation zone at the location of the hollow tubular cooling element. In another example, the ventilation zone at the location of the downstream hollow tubular element may be provided in addition to the ventilation zone provided at the location of the hollow tubular cooling element.

[0337] A ventilation zone at a location along the downstream hollow tubular element may include a plurality of perforations through the circumferential wall of the downstream hollow tubular element. Preferably, a ventilation zone at a location along the downstream hollow tubular element includes at least one circumferential row of perforations. In some embodiments, a ventilation zone may include two circumferential rows of perforations. For example, the perforations may be formed online during manufacture of the aerosol-generating article. Preferably, each circumferential row of perforations includes between 8 and 30 perforations.

[0338] The distance between the ventilation zone and the upstream end of the downstream hollow tubular element may be at least 1 millimeter. The distance between the ventilation zone and the upstream end of the downstream hollow tubular element may be at least 2 millimeters. Preferably, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is at least 3 millimeters.

[0339] Preferably, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is 10 millimeters or less. More preferably, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is 7 millimeters or less. Even more preferably, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is 5 millimeters or less.

[0340] In some embodiments, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is between 1 millimeter and 10 millimeters, preferably between 1 millimeter and 7 millimeters, and more preferably between 1 millimeter and 5 millimeters. In further embodiments, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is between 2 millimeters and 10 millimeters, preferably between 2 millimeters and 7 millimeters, and more preferably between 2 millimeters and 5 millimeters. In other embodiments, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is between 3 millimeters and 10 millimeters, preferably between 3 millimeters and 7 millimeters, and more preferably between 3 millimeters and 5 millimeters.

[0341] Positioning the ventilation zone within the above-mentioned range away from the upstream end of the downstream hollow tubular element has the advantage that it generally ensures that when the aerosol-generating article is inserted into the heating device during use, the ventilation zone is immediately outside the heating device, reducing the risk of the ventilation zone being accidentally blocked by the user's lips or hands.

[0342] The downstream section may optionally further comprise an additional cooling element defining multiple longitudinally extending channels, such as to make a large surface area available for heat exchange. In other words, one such additional cooling element is adapted to function substantially as a heat exchanger. The multiple longitudinally extending channels may be defined by a sheet material that is pleated, gathered, or folded to form the channels. The multiple longitudinally extending channels may be defined by a single sheet that is pleated, gathered, or folded to form the multiple channels. The sheet may also be crimped before being pleated, gathered, or folded. Alternatively, the multiple longitudinally extending channels may be defined by multiple sheets that are crimped, pleated, gathered, or folded to form the multiple channels. In some embodiments, the multiple longitudinally extending channels may be defined by multiple sheets that have been crimped, pleated, gathered, or folded, i.e., two or more sheets that have been brought into an overlay arrangement and then crimped, pleated, gathered, or folded as one.

[0343] As used herein, the term "crimped" refers to a sheet having a plurality of substantially parallel ridges or corrugations. Preferably, the substantially parallel ridges or corrugations extend longitudinally relative to the rod when the aerosol-generating article is assembled. As used herein, the terms "gathered," "pleated," or "folded" mean that a sheet of material is convoluted, folded, or otherwise compressed or contracted in a direction substantially transverse to the cylindrical axis of the rod. The sheet may be crimped before being gathered, pleated, or folded. The sheet may also be gathered, pleated, or folded without prior crimping.

[0344] One such additional cooling element may have a total surface area of ​​about 300 square millimeters per millimeter of length to about 1000 square millimeters per millimeter of length.

[0345] Preferably, the additional cooling element provides a low resistance to airflow through the additional cooling element. Preferably, the additional cooling element does not substantially affect the resistance to airflow through the aerosol-generating article. To achieve this, the longitudinal porosity is preferably greater than 50 percent, and the airflow path through the additional cooling element is preferably relatively unrestricted. The longitudinal porosity of the additional cooling element may be defined by the ratio of the cross-sectional area of ​​the material forming the additional cooling element to the internal cross-sectional area of ​​the aerosol-generating article at the location of the portion including the additional cooling element.

[0346] The additional cooling element comprises a sheet material selected from the group including metal foil, polymeric sheet, and substantially non-porous paper or cardboard. In some embodiments, the aerosol cooling element may comprise a sheet material selected from the group consisting of polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polylactic acid (PLA), cellulose acetate (CA), and aluminum foil. In a particularly preferred embodiment, the additional cooling element comprises a sheet of PLA.

[0347] The aerosol-generating article may have an overall length of between 45 millimeters and 100 millimeters.

[0348] Preferably, the total length of an aerosol-generating article according to the invention is at least 50 millimeters. More preferably, the total length of an aerosol-generating article according to the invention is at least 60 millimeters. More preferably, the total length of an aerosol-generating article according to the invention is at least 65 millimeters. Even more preferably, the total length of an aerosol-generating article according to the invention is at least 70 millimeters.

[0349] Preferably, the overall length of an aerosol-generating article according to the present invention is 90 mm or less, more preferably 85 mm or less, and even more preferably 80 mm or less.

[0350] In some embodiments, the total length of the aerosol-generating article is preferably between 50 millimeters and 90 millimeters, more preferably between 60 millimeters and 90 millimeters, more preferably between 65 millimeters and 90 millimeters, and even more preferably between 70 millimeters and 90 millimeters. In other embodiments, the total length of the aerosol-generating article is preferably between 50 millimeters and 85 millimeters, more preferably between 60 millimeters and 85 millimeters, and even more preferably between 70 millimeters and 85 millimeters. In further embodiments, the total length of the aerosol-generating article is preferably between 50 millimeters and 80 millimeters, more preferably between 60 millimeters and 80 millimeters, and even more preferably between 70 millimeters and 80 millimeters. In an exemplary embodiment, the total length of the aerosol-generating article is 75 millimeters.

[0351] The aerosol-generating article preferably has an outer diameter of at least 5 millimeters along the entire length of the article. If the diameter varies along the length of the aerosol-generating article, the outer diameter is preferably at least 5 millimeters at all positions along the length of the article.

[0352] Preferably, the aerosol-generating article has an outer diameter of at least 5.5 millimeters along the entire length of the article. More preferably, the aerosol-generating article has an outer diameter of at least 6 millimeters along the entire length of the article.

[0353] Preferably, the aerosol-generating article has a maximum outer diameter of less than 10 millimeters. This means that if the diameter of the aerosol-generating article varies along the length of the article, the diameter is less than 10 millimeters at all points along the length. More preferably, the aerosol-generating article has a maximum outer diameter of less than 9 millimeters. Even more preferably, the aerosol-generating article has a maximum outer diameter of less than 8 millimeters. Even more preferably, the aerosol-generating article has a maximum outer diameter of less than 7 millimeters.

[0354] In some embodiments, the aerosol-generating article has an outer diameter of 5 mm to 10 mm, preferably 5.5 mm to 10 mm, more preferably 6 mm to 10 mm. In other embodiments, the aerosol-generating article has an outer diameter of 5 mm to 9 mm, preferably 5.5 mm to 9 mm, more preferably 6 mm to 9 mm. In a further embodiment, the aerosol-generating article has an outer diameter of 5 mm to 8 mm, preferably 5.5 mm to 8 mm, more preferably 6 mm to 8 mm. In a further embodiment, the aerosol-generating article has an outer diameter of 5 mm to 7 mm, preferably 5.5 mm to 7 mm, more preferably 6 mm to 7 mm.

[0355] The outer diameter of the aerosol-generating article may be substantially constant along the entire length of the article. Alternatively, different portions of the aerosol-generating article may have different outer diameters.

[0356] In a particularly preferred embodiment, one or more of the components of the aerosol-generating article are individually enclosed by their own wrapper.

[0357] In one embodiment, the rod of aerosol-generating substrate and the downstream filter segment are individually wrapped. The upstream element, the rod of aerosol-generating substrate, and the hollow tubular element are then combined together with an outer wrapper. They are then combined with the downstream filter segment, which has its own wrapper, by tipping paper.

[0358] Preferably, at least one of the components of the aerosol-generating article is enclosed in a hydrophobic wrapper.

[0359] The term "hydrophobicity" 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 traditionally measured through a liquid where the liquid / vapor interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid via Young's equation. Hydrophobicity or water contact angle may be determined by utilizing the TAPPI T558 test method, and the results are expressed as interfacial contact angles, reported in degrees, which can range from approximately zero to approximately 180 degrees.

[0360] In preferred embodiments, the hydrophobic wrapper comprises a paper layer having a water contact angle of about 30 degrees or greater, preferably about 35 degrees or greater, or about 40 degrees or greater, or about 45 degrees or greater.

[0361] By way of example, the paper layer may comprise PVOH (polyvinyl alcohol) or silicone. The PVOH may be applied to the paper layer as a surface coating, or the paper layer may comprise a surface treatment that includes PVOH or silicone.

[0362] In a particularly preferred embodiment, an aerosol-generating article according to the present invention comprises, in a linear, continuous arrangement, an upstream element, a rod of aerosol-generating substrate located immediately downstream of the upstream element, a hollow tubular cooling element located immediately downstream of the rod of aerosol-generating substrate, a downstream filter segment located immediately downstream of the hollow tubular cooling element, a downstream hollow tubular element located immediately downstream of the downstream filter segment, and one or more outer wrappers combining the components. The upstream element defines the upstream section of the aerosol-generating article. The hollow tubular cooling element, downstream filter segment, and downstream hollow tubular element form the downstream section of the aerosol-generating article.

[0363] The rod of the aerosol-generating substrate may abut against the upstream element. The hollow tubular cooling element may abut against the rod of the aerosol-generating substrate. The downstream filter segment may abut against the hollow tubular cooling element. The downstream hollow tubular element may abut against the downstream filter segment. Preferably, the hollow tubular cooling element abuts against the rod of the aerosol-generating substrate, the downstream filter segment abuts against the hollow tubular cooling element, and the downstream hollow tubular element abuts against the downstream filter segment.

[0364] The present disclosure also relates to an aerosol generation system comprising an aerosol generating device having a distal end and a mouth end. The aerosol generating device may comprise a body. The body or housing of the aerosol generating device may define a device cavity for removably receiving an aerosol-generating article at the mouth end of the device. The aerosol generating device may comprise a heating element or heater for heating the aerosol-generating substrate when the aerosol-generating article is received within the device cavity.

[0365] The device cavity may be referred to as the heating chamber of the aerosol-generating device. The device cavity may extend between a distal end and an oral (or proximal) end. The distal end of the device cavity may be a closed end, and the oral (or proximal) end of the device cavity may be an open end. The aerosol-generating article may be inserted into the device cavity or heating chamber through the open end of the device cavity. The device cavity may be cylindrical in shape to fit the same shape of the aerosol-generating article.

[0366] The phrase "received within" may refer to the fact that a component or element is completely or partially received within another component or element. For example, the phrase "an aerosol-generating article is received within a device cavity" refers to the aerosol-generating article being completely or partially received within the device cavity of the aerosol-generating article. When the aerosol-generating article is received within the device cavity, the aerosol-generating article may abut 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.

[0367] The length of the device cavity may be between 10 mm and 50 mm. The length of the device cavity may be between 20 mm and 40 mm. The length of the device cavity may be between 25 mm and 30 mm.

[0368] The length of the device cavity (or heating chamber) may be the same as or longer than the length of the rod of the aerosol-generating substrate. 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 rod of the aerosol-generating substrate. Preferably, the length of the device cavity is such that, when the aerosol-generating article is received with the aerosol-generating device, at least 75 percent of the length of the rod of the aerosol-generating substrate is inserted or received within the device cavity. More preferably, the length of the device cavity is such that, when the aerosol-generating article is received with the aerosol-generating device, at least 80 percent of the length of the rod of the aerosol-generating substrate is inserted or received within the device cavity. More preferably, the length of the device cavity is such that, when the aerosol-generating article is received with the aerosol-generating device, at least 90 percent of the length of the rod of the aerosol-generating substrate is inserted or received within the device cavity. This maximizes the length of the rod of the aerosol-generating substrate that can heat the aerosol-generating substrate during use, thereby optimizing aerosol generation from the aerosol-generating substrate and reducing tobacco waste.

[0369] The length of the device cavity may be such that when an aerosol-generating article is received in the device cavity, the downstream section, or a portion thereof, protrudes from the device cavity. The length of the device cavity may be such that when an aerosol-generating article is received in 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 an aerosol-generating article is received in the device cavity, a portion of the downstream section (such as a hollow tubular cooling element or a downstream filter segment) is received within the device cavity.

[0370] 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.

[0371] At least 30 percent of the length of the hollow tubular element may be inserted or received within the device cavity when the aerosol-generating article is received within the device. At least 40 percent of the length of the hollow tubular element may be inserted or received within the device cavity when the aerosol-generating article is received within the device. At least 50 percent of the length of the hollow tubular element may be inserted or received within the device cavity when the aerosol-generating article is received within the device. Various lengths of hollow tubular elements are described in more detail within this disclosure.

[0372] Optimizing the amount or length of an article inserted into an aerosol-generating device may increase resistance to inadvertent removal of the article during use. In particular, during heating of the aerosol-generating substrate, the substrate may shrink, which may reduce its outer diameter, thereby reducing the extent to which an inserted portion of an article inserted into the device can frictionally engage with the device cavity. The inserted portion of the article, or the portion of the article configured to be received within the device cavity, may be the same length as the device cavity.

[0373] The length of the device cavity may be between 15 mm and 80 mm. The length of the device cavity is preferably between 20 mm and 70 mm. The length of the device cavity is more preferably between 25 mm and 60 mm. The length of the device is more preferably between 25 mm and 50 mm.

[0374] The length of the device cavity may be between 25 mm and 29 mm. Preferably, the length of the device cavity is between 25 mm and 29 mm. More preferably, the length of the device cavity is between 26 mm and 29 mm. Even more preferably, the length of the device cavity is 27 mm or 28 mm.

[0375] The diameter of the device cavity may be between 4 mm and 10 mm. The diameter of the device cavity may be between 5 mm and 9 mm. The diameter of the device cavity may be between 6 mm and 8 mm. The diameter of the device cavity may be between 6 mm and 7 mm.

[0376] The diameter of the device cavity may be substantially the same as or larger than the diameter of the aerosol-generating article, and may be the same as the diameter of the aerosol-generating article to establish a tight fit therewith.

[0377] The device cavity may be configured to establish a tight fit with an aerosol-generating article received within the device cavity. A tight fit may refer to a slip fit. The aerosol-generating device may include a peripheral wall. Such a peripheral wall may define the device cavity or a heating chamber. The peripheral wall defining the device cavity may be configured to engage in a tight fit with an aerosol-generating article received within the device cavity such that, when received within the device, there is substantially no gap or empty space between the peripheral wall defining the device cavity and the aerosol-generating article.

[0378] Such an airtight fit may establish an airtight fit or configuration between the device cavity and the aerosol-generating article received therein.

[0379] In such an airtight configuration, there are substantially no gaps or empty spaces between the peripheral walls defining the device cavity and the aerosol-generating article for air to flow through.

[0380] A 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.

[0381] The aerosol generating device may include an airflow channeling extending between the channel inlet and the channel outlet. The airflow channel may be configured to establish fluid communication between the interior of the device cavity and the exterior of the aerosol generating device. The airflow channel of the aerosol generating device may be defined within the housing of the aerosol generating device to enable fluid communication between the interior of the device cavity and the exterior of the aerosol generating device. When an aerosol-generating article is received within the device cavity, the airflow channel may be configured to provide air flow into the article to deliver the generated aerosol to a user who inhales through the mouth end of the article.

[0382] 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 a combination of both. The airflow channel may be partially defined by the inner surface of the peripheral wall, or partially defined within the thickness of the peripheral wall. The inner surface of the peripheral wall defines the periphery of the device cavity.

[0383] The airflow channel of the aerosol generating device may extend from an inlet located at the oral or proximal end of the aerosol generating device to an outlet located away from the oral end of the device. The airflow channel may extend along a direction parallel to the longitudinal axis of the aerosol generating device.

[0384] The heater may be any suitable type of heater, although in the present invention it is preferred that the heater is an external heater.

[0385] Preferably, the heater may externally heat the aerosol-generating article when received within the aerosol-generating device. Such an external heater may surround the aerosol-generating article when inserted into or received within the aerosol-generating device.

[0386] In some embodiments, the heater is arranged to heat the outer surface of the aerosol-generating substrate. In some embodiments, the heater is arranged for insertion into the aerosol-generating substrate when the aerosol-generating substrate is received within the cavity. The heater may be located within the device cavity or heating chamber.

[0387] The heater may include at least one heating element. The at least one heating element may be any suitable type of heating element. In some embodiments, the device includes only one heating element. In some embodiments, the device includes multiple heating elements. The heater may include at least one resistive heating element. Preferably, the heater includes multiple resistive heating elements. Preferably, the resistive heating elements are electrically connected in a parallel arrangement. Advantageously, providing multiple resistive heating elements electrically connected in a parallel arrangement may facilitate delivery of desired power to the heater while reducing or minimizing the voltage required to provide the desired power. Advantageously, reducing or minimizing the voltage required to operate the heater may facilitate reducing or minimizing the physical size of the power supply.

[0388] Suitable materials for forming the at least one resistive heating element include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilicide), carbon, graphite, metals, metal alloys, and composites made of ceramic and metallic materials. Such composites may include doped or undoped ceramics. An example of a suitable doped ceramic is doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, and platinum group metals. Examples of suitable metal alloys include stainless steel, nickel-, cobalt-, chromium-, aluminum-, titanium-, zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese-, and iron-containing alloys, as well as nickel-, iron-, cobalt-, and stainless steel-based superalloys, Timetal®, and iron-manganese-aluminum-based alloys.

[0389] In some embodiments, the at least one resistive heating element comprises one or more stamped sections of an electrically resistive material (such as stainless steel), or alternatively, the at least one resistive heating element may comprise a heating wire or filament (e.g., Ni-Cr (nickel-chromium), platinum, tungsten, or alloy wire).

[0390] In some embodiments, the at least one heating element comprises an electrically insulating substrate and the at least one resistive heating element is provided on the electrically insulating substrate.

[0391] The electrically insulating substrate may comprise any suitable material. For example, the electrically insulating substrate may comprise one or more of paper, glass, ceramic, anodized metal, coated metal, and polyimide. The ceramic may comprise mica, alumina (Al2O3), or zirconia (ZrO2). The electrically insulating substrate preferably has a thermal conductivity of about 40 watts per meter Kelvin or less, preferably about 20 watts per meter Kelvin or less, and ideally about 2 watts per meter Kelvin or less.

[0392] The heater may comprise a heating element comprising a rigid, electrically insulating substrate having one or more conductive tracks or wires disposed on its surface. The size and shape of the electrically insulating substrate may allow the heater to be inserted directly into the aerosol-generating substrate. If the electrically insulating substrate is not sufficiently rigid, the heating element may include further reinforcing means. Electric current may be passed through one or more conductive tracks to heat the heating element and the aerosol-generating substrate.

[0393] In some embodiments, the heater comprises an induction heating arrangement. The induction heating device may comprise an inductor coil and a power source configured to provide a high-frequency oscillating current to the inductor coil. As used herein, high-frequency oscillating current means an oscillating current having a frequency between about 500 kHz and about 30 MHz. The heater may advantageously comprise a DC / AC inverter for converting DC current provided by a DC power source into alternating current. The inductor coil may be arranged to generate a high-frequency oscillating electromagnetic field upon receiving the high-frequency oscillating current from the power source. The inductor coil may be positioned to generate a high-frequency oscillating electromagnetic field within the device cavity. In some embodiments, the inductor coil may substantially surround the device cavity. The inductor coil may extend at least partially along the length of the device cavity.

[0394] The heater may include an induction heating element. The induction heating element may be a susceptor element. As used herein, the term "susceptor element" refers to an element comprising a material capable of converting electromagnetic energy into heat. When the susceptor element is positioned within an alternating electromagnetic field, the susceptor is heated. Heating of the susceptor element may be the result of at least one of hysteresis losses and eddy currents induced within the susceptor, depending on the electrical and magnetic properties of the susceptor material.

[0395] The susceptor element may be arranged such that when an aerosol-generating article is received within the cavity of the aerosol-generating device, the oscillating electromagnetic field generated by the inductor coil induces current flow in the susceptor element, heating the susceptor element. In these embodiments, the aerosol-generating device is preferably capable of generating a fluctuating electromagnetic field having a magnetic field strength (H-field strength) of 1 to 5 kiloamperes per meter (kA / m), preferably 2 to 3 kA / m, e.g., about 2.5 kA / m. Electrically operated aerosol generators are preferably capable of generating a fluctuating electromagnetic field having a frequency of 1 to 30 MHz, e.g., 1 to 10 MHz, e.g., 5 to 7 MHz.

[0396] In these embodiments, the susceptor element is preferably positioned in contact with the aerosol-generating substrate. In some embodiments, the susceptor element is positioned within the aerosol-generating device. In these embodiments, the susceptor element may be positioned within a cavity. The aerosol-generating device may include only one susceptor element. The aerosol-generating device may include multiple susceptor elements. In some embodiments, the susceptor element is preferably positioned to heat the outer surface of the aerosol-generating substrate.

[0397] The susceptor elements may comprise any suitable material. They may be formed from any material that can be inductively heated to a temperature sufficient to release volatile compounds from the aerosol-generating substrate. Suitable materials for the elongated susceptor elements include graphite, molybdenum, silicon carbide, stainless steel, niobium, aluminum, nickel, nickel-containing compounds, titanium, and composites of metallic materials. Some susceptor elements comprise metal or carbon. Advantageously, the susceptor elements may comprise or consist of ferromagnetic materials, such as ferritic iron, ferromagnetic steel, or stainless steel, ferromagnetic particles, and ferrite. Suitable susceptor elements may be or include aluminum. The susceptor elements preferably comprise more than about 5 percent, preferably more than 20 percent, more preferably more than 50 percent, or even more than 90 percent ferromagnetic or paramagnetic material. Some elongated susceptor elements may be heated to temperatures exceeding 250 degrees Celsius.

[0398] The susceptor element may comprise a non-metallic core having a metallic layer disposed thereon, for example, the susceptor element may include a ceramic core or metallic tracks formed on the outer surface of the substrate.

[0399] In some embodiments, the aerosol generating device may comprise at least one resistive heating element and at least one inductive heating element, hi some embodiments, the aerosol generating device may comprise a combination of resistive and inductive heating elements.

[0400] In use, the heater can be controlled to operate within a defined operating temperature range that is less than 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.

[0401] Preferably, the operating temperature range of the heater may be between about 150 degrees Celsius and about 200 degrees Celsius. More preferably, the operating temperature range of the heater may be between about 180 degrees Celsius and about 200 degrees Celsius. Specifically, as described in this disclosure, it has been discovered that optimal and consistent aerosol delivery can be achieved when using an aerosol generating device having an external heater with an operating temperature range of about 180 degrees Celsius to about 200 degrees Celsius, with an aerosol-generating article having a relatively low RTD (e.g., having an RTD in the downstream section of less than 15 millimeters HO).

[0402] In embodiments in which the aerosol-generating article includes a ventilation zone at a location along the downstream section or hollow tubular element, the ventilation zone may be disposed so as to be exposed when the aerosol-generating article is received within the device cavity. Thus, the length of the device cavity or heating chamber may be less than the distance from the upstream end of the aerosol-generating article to the ventilation zone located along the downstream section. In other words, when the aerosol-generating article is received within the aerosol-generating device, the distance between the ventilation zone and the upstream end of the upstream element may be greater than the length of the heating chamber.

[0403] When the article is received within the device cavity, the ventilation zone may be located at least 0.5 millimeters (in the downstream direction of the article) from the mouth end (or mouth end face) of the device cavity or the device itself. When the article is received within the device cavity, the ventilation zone may be located at least 1 millimeter (in the downstream direction of the article) from the mouth end (or mouth end face) of the device cavity or the device itself. When the article is received within the device cavity, the ventilation zone may be located at least 2 millimeters (in the downstream direction of the article) from the mouth end (or mouth end face) of the device cavity or the device itself.

[0404] The ratio between the distance between the ventilation zone and the upstream end of the upstream element and the length of the heating chamber is preferably between 1.03 and 1.13.

[0405] This positioning of the ventilation zone ensures that the ventilation zone is not blocked within the device cavity itself, while also minimizing the risk of blockage by the user's lips or hands, as the ventilation zone is located as far upstream from the downstream end of the article as is reasonably possible without becoming blocked within the device cavity.

[0406] The aerosol-generating device may include 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., 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 rechargeable and may have a capacity that allows for the storage of sufficient energy for one or more user operations, e.g., one or more aerosol-generating experiences. For example, the power source may have a capacity sufficient to allow continuous heating of the aerosol-generating substrate for approximately six minutes, corresponding to the typical time it takes to smoke a conventional cigarette, or for a multiple of six minutes. In another example, the power source may have a capacity sufficient to allow for a predetermined number of puffs or for discontinuous activation of the heater. [Example]

[0407] 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 features of another example, embodiment, or aspect described herein.

[0408] Example 1 An aerosol-generating article comprising a rod of aerosol-generating substrate. Example 2. An aerosol-generating article as described in example 1, wherein the rod of the aerosol-generating substrate has a length of at least 17 millimeters. Example 3 3. An aerosol-generating article according to any one of Examples 1 to 2, wherein the rod of aerosol-generating substrate comprises tobacco material. Example 4. 4. The aerosol-generating article of example 3, wherein the tobacco material has a density of less than 350 milligrams per cubic centimeter. Example 5. 5. The aerosol-generating article of example 4, wherein the tobacco material has a density of less than 300 milligrams per cubic centimeter. Example 6 6. The aerosol-generating article of Example 3, 4, or 5, wherein the tobacco material has a density of at least 100 milligrams per cubic centimeter. Example 7 4. The aerosol-generating article of example 3, wherein the tobacco material has a density of between 150 milligrams per cubic centimeter and 500 milligrams per cubic centimeter. Example 8 8. The aerosol-generating article of Example 7, wherein the tobacco material has a density of between 200 milligrams per cubic centimeter and 400 milligrams per cubic centimeter. Example 9. An aerosol-generating article as described in any one of Examples 1 to 8, comprising a downstream section provided downstream of the rod of the aerosol-generating substrate. Example 10. An aerosol-generating article as described in Example 9, wherein the downstream section comprises a hollow tubular element abutting the downstream end of the rod of the aerosol-generating substrate. Example 11 An aerosol-generating article as described in Example 10, wherein the hollow tubular element has a length of at least 40 millimeters. Example 12 10. The aerosol-generating article of example 9, wherein the downstream section comprises a downstream filter segment. Example 13 An aerosol-generating article as described in Example 12, wherein the downstream section comprises a ventilation zone located downstream of the downstream filter segment. Example 14. 14. The aerosol-generating article of example 12 or 13, wherein the downstream filter segment is a solid plug. Example 15. 15. An aerosol-generating article according to any one of Examples 12 to 14, comprising a downstream hollow tubular element, the downstream tubular element being located downstream of the downstream filter segment. Example 16. 16. The aerosol-generating article of Example 15, wherein the downstream hollow tubular element abuts the downstream end of the downstream filter segment. Example 17. 17. The aerosol-generating article of Example 15 or 16, wherein the ventilation zone is located along the downstream hollow tubular element. Example 18. 18. The aerosol-generating article of Example 17, wherein the ventilation zone is located toward the upstream end of the downstream hollow tubular element. Example 19. 19. An aerosol-generating article according to any one of Examples 12 to 18, wherein the downstream section comprises a hollow tubular cooling element, and the downstream filter segment abuts the downstream end of the hollow tubular cooling element. Example 20. 20. An aerosol-generating article according to any one of Examples 12 to 19, wherein the downstream filter segment has a length of at least 5 millimeters. Example 21. 21. An aerosol-generating article according to any one of Examples 12 to 20, wherein the downstream filter segment has a length of 20 millimeters or less. Example 22. 22. An aerosol-generating article according to any one of Examples 12 or 21, wherein the downstream filter segment has a length of between 5 millimeters and 20 millimeters. Example 23. 10. The aerosol-generating article of Example 9, wherein the downstream section extends to the downstream end of the aerosol-generating article. Example 24. An aerosol-generating article as described in Example 9 or 23, wherein the downstream section comprises a hollow tubular cooling element. Example 25. 25. The aerosol-generating article of example 24, wherein the hollow tubular cooling element has a length of at least 20 millimeters. Example 26. 26. An aerosol-generating article as described in Example 25, wherein the hollow tubular cooling element has a length of at least 25 millimeters. Example 27. 27. An aerosol-generating article according to any one of Examples 24 to 26, wherein the hollow tubular cooling element has a length of 50 millimeters or less. Example 28. 28. The aerosol-generating article of Example 27, wherein the hollow tubular cooling element has a length of between 20 millimeters and 50 millimeters. Example 29. 27. An aerosol-generating article according to any one of Examples 9 or 23-26, wherein the downstream section has a length of at least 45 millimeters. Example 30. 30. An aerosol-generating article according to any one of Examples 1 to 29, wherein the maximum outer diameter of the aerosol-generating article is less than 8 millimeters. Example 31. 31. The aerosol-generating article of Example 30, wherein the aerosol-generating article has a maximum outer diameter of between 5 millimeters and 8 millimeters. Example 32. 32. An aerosol-generating article according to claim 30 or 31, wherein the aerosol-generating article has a maximum outer diameter of 7 millimeters or less. Example 33. 33. The aerosol-generating article of claim 32, wherein the aerosol-generating article has a maximum outer diameter of between 5.5 millimeters and 7 millimeters. Example 34. An aerosol-generating article as described in Example 9, wherein the ratio of the length of the downstream section to the length of the rod of the aerosol-generating substrate is at least 1.5. Example 35. An aerosol-generating article as described in Example 9, wherein the ratio of the length of the downstream section to the overall length of the aerosol-generating article is at least 0.6. Example 36. 36. An aerosol-generating article according to any one of Examples 1 to 35, wherein the aerosol-generating article has a total length of at least 50 millimeters. Example 37. An aerosol-generating article according to any one of Examples 1 to 36, wherein the rod of the aerosol-generating substrate has a length of 40 millimeters or less. Example 38. 38. An aerosol-generating article as described in Example 37, wherein the rod of the aerosol-generating substrate has a length of 36 millimeters or less. Example 39. An aerosol-generating article according to any one of Examples 1 to 38, wherein the rod of the aerosol-generating substrate has a length of 30 millimeters or less. Example 40. An aerosol-generating article according to any one of Examples 1 to 39, wherein the rod of the aerosol-generating substrate has a length of 25 millimeters or less. Example 41. An aerosol-generating article according to any one of Examples 1 to 40, wherein the rod of the aerosol-generating substrate has a length of 20 millimeters or less. Example 42. An aerosol-generating article according to any one of Examples 1 to 41, wherein the ratio of the length of the rod of the aerosol-generating substrate to the overall length of the aerosol-generating article is 0.4 or less. Example 43. An aerosol-generating article according to any one of Examples 1 to 42, wherein the rod of the aerosol-generating substrate has a length of at least 17 millimeters. Example 44. An aerosol-generating article according to any one of Examples 1 to 43, wherein the rod of the aerosol-generating substrate has a length of at least 20 millimeters. Example 45. An aerosol-generating article according to any one of Examples 1 to 44, wherein the rod of the aerosol-generating substrate has a length of at least 25 millimeters. Example 46. An aerosol-generating article according to any one of Examples 1 to 45, wherein the rod of the aerosol-generating substrate has a length of at least 29 millimeters. Example 47. An aerosol-generating article according to any one of Examples 1 to 46, wherein the rod of the aerosol-generating substrate has a length of 29 mm to 36 mm. Example 48. An aerosol-generating article according to any one of Examples 1 to 47, comprising an upstream element. Example 49. 49. The aerosol-generating article of Example 48, wherein the upstream element is provided upstream of the rod of the aerosol-generating substrate. Example 50. 50. The aerosol-generating article of any one of Examples 48 and 49, wherein the upstream element is provided in contact with the upstream end of the rod of the aerosol-generating substrate. Example 51. 51. An aerosol-generating article according to any one of Examples 48 to 50, wherein the upstream element has a length of between 2 millimeters and 8 millimeters. Example 52. 52. An aerosol-generating article according to any one of Examples 48 to 51, wherein the upstream element has a length of between 2 millimeters and 6 millimeters. Example 53. 53. The aerosol-generating article of any one of Examples 48 to 52, wherein the upstream element has a length of between 4 millimeters and 6 millimeters. Example 54. An aerosol-generating article according to any one of Examples 48 to 53, wherein the upstream element comprises a hollow support segment having a central longitudinal cavity extending therethrough. Example 55. 55. The aerosol-generating article of Example 54, wherein the hollow tubular support element has a wall thickness of less than 1 millimeter. Example 56. 56. An aerosol-generating article according to one of Examples 48 to 55, wherein the resistance to withdrawal (RTD) of the upstream element is 10 millimeters H2O or less. Example 57. 57. An aerosol-generating article according to any one of Examples 1 to 56, wherein the aerosol-generating article has a total length of at least 60 millimeters. Example 58. 58. An aerosol-generating article as described in Example 57, wherein the aerosol-generating article has a total length of at least 65 millimeters. Example 59. 59. The aerosol-generating article of any one of Examples 1 to 58, wherein the aerosol-generating article has a total length of 90 millimeters or less. Example 60. 60. The aerosol-generating article of any one of Examples 1 to 59, wherein the aerosol-generating article has a total length of 65 mm to 90 mm. Example 61. 61. An aerosol-generating article according to any one of Examples 1 to 60, wherein the rod of aerosol-generating substrate comprises one or more aerosol-forming bodies. Example 62. 62. An aerosol-generating article as described in Example 61, wherein the rod of aerosol-generating substrate has an aerosol former content of 30 weight percent or less on a dry weight basis. Example 63. 63. An aerosol-generating article as described in Example 62, wherein the rod of aerosol-generating substrate has an aerosol former content of 20 weight percent or less on a dry weight basis. Example 64. 64. An aerosol-generating article as described in Example 63, wherein the rod of aerosol-generating substrate has an aerosol former content of 10 weight percent or less on a dry weight basis. Example 65. 63. The aerosol-generating article of claim 62, wherein the rod of aerosol-generating substrate has an aerosol former content of 10 weight percent to 30 weight percent on a dry weight basis. Example 66. 66. The aerosol-generating article of any one of Examples 61 to 65, wherein the one or more aerosol formers comprise one or more of glycerin and propylene glycol. Example 67. An aerosol-generating article according to any one of Examples 1 to 66, wherein the ratio of the length of the upstream element to the length of the hollow tubular element in the downstream section is between 0.01 and 0.15. Example 68. 68. The aerosol-generating article of any one of Examples 3 to 67, wherein the tobacco material comprises shredded tobacco material. Example 69. An aerosol-generating article according to any one of Examples 1 to 68, wherein the ratio between the length of the rod of the aerosol-generating substrate and the overall length of the aerosol-generating article is at least 0.2, preferably 0.25. Example 70. 1. An aerosol generating system comprising: An aerosol-generating article according to any one of Examples 1 to 69, and An aerosol generating system comprising an aerosol generating device comprising a heated chamber for receiving an aerosol-generating article and at least one heating element provided at or near the periphery of the heated chamber.

[0409] The aerosol-generating article shown in all figures of this disclosure comprises a rod of aerosol-generating substrate 12 and a downstream section 14 located downstream of the rod of aerosol-generating substrate 12. The aerosol-generating article extends from an upstream or distal end 18 to a downstream or mouth end 19. The downstream or mouth end 19 is defined by the downstream end of the downstream section 14.

[0410] Each of the components of the aerosol-generating articles shown in the figures and described in this disclosure may be surrounded by a corresponding wrapper or may be bound together by one or more wrappers not shown in the figures. Unless otherwise specified, the maximum outer diameter of each of the aerosol-generating articles shown in the figures is about 6.5 mm.

[0411] The rod 12 of aerosol-generating substrate is surrounded by a wrapper (not shown) and contains at least one type of aerosol-generating substrate as described herein, such as vegetable cut filler, particularly tobacco cut filler, homogenized tobacco, a gel formulation, or homogenized plant material containing particles of plants other than tobacco. The rods 12 of aerosol-generating articles shown in all figures have an average tobacco density of about 250 mg per cubic centimeter.

[0412] The downstream section 14 of the aerosol-generating article 10 shown in Figure 1 comprises a hollow tubular cooling element 22, a downstream filter segment 24, and a hollow tubular element 26 at its downstream or mouth end. The hollow tubular cooling element 22 is located immediately downstream of the rod 12 of the aerosol-generating substrate. In other words, the hollow tubular cooling element 22 abuts the downstream end of the rod 12. The downstream filter segment 24 abuts the downstream end of the hollow tubular cooling element 22, and the downstream hollow tubular element 26 abuts the downstream end of the downstream filter segment 24. Thus, the downstream filter segment 24 is located between the hollow tubular cooling element 22 and the downstream hollow tubular element 26. The downstream end 19 of the article 10 is defined by the downstream end of the downstream hollow tubular element 26.

[0413] The length of the rod 12 of the aerosol-generating substrate is about 40 mm.

[0414] The hollow tubular cooling element 22 is provided in the form of a hollow cylindrical tube made of cardboard or cellulose acetate. The hollow tubular cooling segment 22 defines an interior cavity extending entirely from the upstream end of the hollow tubular cooling element 22 to the downstream end of the hollow tubular cooling element 22. The interior cavity is substantially empty, thereby permitting substantially unrestricted airflow along the interior cavity. The hollow tubular cooling element 22 may not contribute substantially to the overall RTD of the aerosol-generating article 10. The length of the hollow tubular cooling element 22 is approximately 25 mm. The wall thickness of the hollow tubular cooling element 22 is approximately 250 micrometers (μm).

[0415] The downstream filter segment 24 comprises a cylindrical plug of cellulose acetate tow and is approximately 10 mm in length.

[0416] The downstream hollow tubular element 26 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The downstream hollow tubular element 26 defines an interior cavity extending entirely from the upstream end of the downstream hollow tubular element 26 to the downstream end of the downstream hollow tubular element 26. The interior cavity is substantially empty, thereby permitting substantially unrestricted airflow along the interior cavity. The downstream hollow tubular element 26 does not substantially contribute to the overall RTD of the aerosol-generating article 10. The length of the downstream hollow tubular element 26 is approximately 6 mm. The wall thickness of the downstream hollow tubular element 26 is approximately 1 mm.

[0417] The aerosol-generating article 10 includes a ventilation zone 36 provided along the hollow tubular cooling element 22. The ventilation zone 36 comprises at least one circumferential row of perforations extending through the peripheral wall of the hollow tubular cooling element 22 and an optional wrapper (not shown) surrounding the hollow tubular cooling element 22. The ventilation zone 36 is provided approximately 2 millimeters from the downstream end of the hollow tubular cooling element 22.

[0418] The aerosol-generating article 101 shown in Figure 2 is similar to the aerosol-generating article 10 shown in Figure 1, differing only in the following respects: the aerosol-generating substrate rod 12 is shorter and the hollow tubular cooling element 22 is longer. The aerosol-generating substrate rod 12 is approximately 25 mm long. The hollow tubular cooling element 22 is approximately 40 mm long.

[0419] The aerosol-generating article 102 shown in Figure 3a is similar to the aerosol-generating article 101 shown in Figure 2, differing only in the following respects: the hollow tubular cooling element 22 is shorter and the downstream hollow tubular element 27 is longer. The hollow tubular cooling element 22 has a length of approximately 25 mm. The downstream hollow tubular element 27 has a length of approximately 20 mm. In addition, a ventilation zone 36 is provided along the downstream hollow tubular element 27. The ventilation zone 36 is provided approximately 2 mm from the upstream end of the downstream hollow tubular element 26. The ventilation zone 36 comprises at least one circumferential row of perforations extending through the peripheral wall of the downstream hollow tubular element 27 and an optional wrapper (not shown) surrounding the downstream hollow tubular element 27.

[0420] The aerosol-generating article 103 shown in Figure 3b is similar to the aerosol-generating article 102 shown in Figure 3a and differs only in the following respects: the downstream hollow tubular element 27 comprises two adjacent hollow tubular segments 271, 272. The first hollow tubular segment 271 is located between the downstream filter segment 24 and the second hollow tubular segment 272.

[0421] In FIG. 3b, the first hollow tubular segment 271 is provided in the form of a hollow cylindrical tube made of cardboard. The first hollow tubular segment 271 defines an interior cavity extending entirely from the upstream end of the first hollow tubular segment 271 to the downstream end of the first hollow tubular segment 271. The interior cavity is substantially empty, thereby permitting substantially unrestricted airflow along the interior cavity. The first hollow tubular segment 271 may not contribute substantially to the overall RTD of the aerosol-generating article 103. The length of the first hollow tubular segment 271 is approximately 10 mm. The wall thickness of the first hollow tubular segment 271 is approximately 250 micrometers (μm). The ventilation zone 36 is provided approximately 2 millimeters from the upstream end of the first hollow tubular segment 271 of the downstream hollow tubular element 27.

[0422] In Figure 3b, the second hollow tubular segment 272 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The second hollow tubular segment 272 defines an interior cavity extending entirely from the upstream end of the second hollow tubular segment 272 to the downstream end of the second hollow tubular segment 272. The interior cavity is substantially empty, thereby permitting substantially unrestricted airflow along the interior cavity. The second hollow tubular segment 272 does not substantially contribute to the overall RTD of the aerosol-generating article 103. The length of the second hollow tubular segment 272 is approximately 10 mm. The wall thickness of the second hollow tubular segment 272 is approximately 1 mm.

[0423] The aerosol-generating articles 104, 105 shown in Figures 4a and 4b are similar to the aerosol-generating article 101 shown in Figure 2, differing only in that the aerosol-generating articles 104, 105 further comprise an upstream section 16 located upstream of the rod 12 of the aerosol-generating substrate. The distal ends 18 of the articles 104, 105 are defined by the upstream end of the upstream section 16. The upstream section 16 comprises upstream elements 341, 342 that abut the upstream end of the rod 12. The upstream elements 341, 342 have a length of approximately 5 mm. In the article 104 shown in Figure 4a, the upstream element 341 is provided in the form of a cylindrical plug of cellulose acetate tow. In the article 105 shown in Figure 4b, the upstream element 342 is provided in the form of a hollow cylindrical tube made of cellulose acetate having a wall thickness of approximately 1 mm.

[0424] The downstream section 14 of the aerosol-generating article 20 shown in Figure 5 comprises a hollow tubular support element 28, a cooling element 32, and a downstream filter segment 24. The hollow tubular support element 28 is located immediately downstream of the rod 12 of the aerosol-generating substrate. In other words, the hollow tubular support element 28 abuts the downstream end of the rod 12. The cooling element 32 abuts the downstream end of the hollow tubular support element 28, and the downstream filter segment 24 abuts the downstream end of the cooling element 32. Thus, the cooling element 32 is located between the hollow tubular support element 28 and the downstream filter segment 24. The downstream end 19 of the article 20 is defined by the downstream end of the downstream filter segment 24.

[0425] The length of the rod 12 of the aerosol-generating substrate is about 25 mm.

[0426] The hollow tubular support element 28 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The hollow tubular support element 28 defines an interior cavity extending entirely from the upstream end of the hollow tubular support element 28 to the downstream end of the hollow tubular support element 28. The interior cavity is substantially empty, thereby permitting substantially unrestricted airflow along the interior cavity. The hollow tubular support element 28 may not contribute substantially to the overall RTD of the aerosol-generating article 20. The length of the hollow tubular support element 28 is approximately 8 mm. The wall thickness of the hollow tubular support element 28 is approximately 1.5 mm.

[0427] The cooling element 32 is formed from a thin polylactic acid (PLA) material that has been crimped, pleated, gathered, or folded to form channels. The length of the cooling element 32 is approximately 18 mm.

[0428] The downstream filter segment 24 comprises a cylindrical plug of cellulose acetate tow and is approximately 7 mm in length.

[0429] The maximum outer diameter of the aerosol-generating article 20 is about 7.3 mm.

[0430] The aerosol-generating article 201 shown in Figure 6 is similar to the aerosol-generating article 20 shown in Figure 5, except that it further comprises a hollow tubular cooling element 22 and that the aerosol-generating substrate rod 12 is shorter. The aerosol-generating substrate rod 12 has a length of approximately 12 mm. The hollow tubular cooling element 22 is located immediately downstream of the cooling element 32 and immediately upstream of the downstream filter segment 24. In other words, the hollow tubular cooling element 22 abuts the cooling element 32 and the downstream filter segment 24.

[0431] The hollow tubular cooling element 22 is provided in the form of a hollow cylindrical tube made of cardboard. The hollow tubular cooling segment 22 defines an interior cavity that extends entirely from the upstream end of the hollow tubular cooling element 22 to the downstream end of the hollow tubular cooling element 22. The interior cavity is substantially empty, thereby allowing substantially unrestricted airflow along the interior cavity. The hollow tubular cooling element 22 may not contribute substantially to the overall RTD of the aerosol-generating article 201. The length of the hollow tubular cooling element 22 is approximately 25 mm. The wall thickness of the hollow tubular cooling element 22 is approximately 250 micrometers (μm).

[0432] The aerosol-generating article 202 shown in Figure 7 is similar to the aerosol-generating article 201 shown in Figure 6, and differs only in that it further comprises a downstream hollow tubular element 27. The downstream hollow tubular element 27 abuts the downstream end of the downstream filter segment 24. The downstream filter segment 24 is therefore located between the hollow tubular cooling element 22 and the downstream hollow tubular element 27. The downstream end 19 of the article 202 is defined by the downstream end of the downstream hollow tubular element 27.

[0433] The downstream hollow tubular element 27 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The downstream hollow tubular element 27 defines an internal cavity extending entirely from the upstream end of the downstream hollow tubular element 27 to the downstream end of the downstream hollow tubular element 27. The internal cavity is substantially empty, thereby allowing substantially unrestricted airflow along the internal cavity. The downstream hollow tubular element 27 may not contribute substantially to the overall RTD of the aerosol-generating article 202. The length of the downstream hollow tubular element 27 is approximately 5 mm. The wall thickness of the downstream hollow tubular element 27 is approximately 1 mm.

[0434] The aerosol-generating article 30 shown in Figure 8 comprises a rod of aerosol-generating substrate 12 and a downstream section 14 located downstream of the rod of aerosol-generating substrate 12. The aerosol-generating article 30 further comprises an upstream section 16 located upstream of the rod of aerosol-generating substrate 12. A distal end 18 of the article 30 is defined by the upstream end of the upstream section 16.

[0435] The downstream section 14 of the aerosol-generating article 30 shown in Figure 8 comprises a hollow tubular cooling element 22 and a downstream filter segment 24. The hollow tubular cooling element 22 is located immediately downstream of the rod 12 of the aerosol-generating substrate. In other words, the hollow tubular cooling element 22 abuts the downstream end of the rod 12. The downstream filter segment 24 abuts the downstream end of the hollow tubular cooling element 22. Thus, the hollow tubular cooling element 22 is located between the rod 12 and the downstream filter segment 24. The downstream end 19 of the article 30 is defined by the downstream end of the downstream filter segment 24.

[0436] The length of the rod 12 of the aerosol-generating substrate is about 25 mm.

[0437] The hollow tubular cooling element 22 is provided in the form of a hollow cylindrical tube made of cardboard or cellulose acetate. The hollow tubular cooling segment 22 defines an interior cavity that extends entirely from the upstream end of the hollow tubular cooling element 22 to the downstream end of the hollow tubular cooling element 22. The interior cavity is substantially empty, thereby allowing substantially unrestricted airflow along the interior cavity. The hollow tubular cooling element 22 may not contribute substantially to the overall RTD of the aerosol-generating article 30. The length of the hollow tubular cooling element 22 is approximately 21 mm. The wall thickness of the hollow tubular cooling element 22 is approximately 250 micrometers (μm).

[0438] The downstream filter segment 24 comprises a cylindrical plug of cellulose acetate tow and is approximately 7 mm in length.

[0439] The upstream section 16 comprises an upstream element 341 which abuts the upstream end of the rod 12. The upstream element 341 is provided in the form of a cylindrical plug of cellulose acetate tow. The length of the upstream element 341 is approximately 5 mm.

[0440] The aerosol-generating article 30 includes a ventilation zone 36 provided along the hollow tubular cooling element 22. The ventilation zone 36 includes at least one circumferential row of perforations extending through the peripheral wall of the hollow tubular cooling element 22 and an optional wrapper (not shown) surrounding the hollow tubular cooling element 22. The ventilation zone 36 is provided approximately 2 millimeters from the downstream end of the hollow tubular cooling element 22.

[0441] The aerosol-generating article 301 shown in Figure 9 is similar to the aerosol-generating article 30 shown in Figure 8, differing only in that the rod 12 is shorter and the hollow tubular cooling element 22 is longer. In Figure 9, the length of the aerosol-generating substrate rod 12 is about 12 mm and the length of the hollow tubular cooling element 22 is about 45 mm.

[0442] The aerosol-generating article 302 shown in Figure 10 is similar to the aerosol-generating article 301 shown in Figure 8, except that the rod 12 is shorter, the hollow tubular cooling element 22 is longer, and the article 302 further comprises a downstream hollow tubular element 27. In Figure 10, the length of the aerosol-generating substrate rod 12 is approximately 12 mm, and the length of the hollow tubular cooling element 22 is approximately 40 mm. Thus, the downstream filter segment 24 is located between the hollow tubular cooling element 22 and the downstream hollow tubular element 27. The downstream end 19 of the article 302 is defined by the downstream end of the downstream hollow tubular element 27.

[0443] The downstream hollow tubular element 27 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The downstream hollow tubular element 27 defines an internal cavity extending entirely from the upstream end of the downstream hollow tubular element 27 to the downstream end of the downstream hollow tubular element 27. The internal cavity is substantially empty, thereby allowing substantially unrestricted airflow along the internal cavity. The downstream hollow tubular element 27 may not contribute substantially to the overall RTD of the aerosol-generating article 302. The length of the downstream hollow tubular element 27 is approximately 5 mm. The wall thickness of the downstream hollow tubular element 27 is approximately 1 mm.

[0444] The aerosol-generating article 304 shown in Figure 11 is similar to the aerosol-generating article 302 shown in Figure 10, except that a ventilation zone 36 is instead provided along the downstream hollow tubular element 27. The ventilation zone 36 is provided approximately 2 millimeters from the upstream end of the downstream hollow tubular element 27. The ventilation zone 36 comprises at least one circumferential row of perforations extending through the peripheral wall of the downstream hollow tubular element 27 and an optional wrapper (not shown) surrounding the downstream hollow tubular element 27.

[0445] 12 comprises a rod of aerosol-generating substrate 12 and a downstream section 14 located downstream of the rod of aerosol-generating substrate 12. The aerosol-generating article 40 further comprises an upstream section 16 located upstream of the rod of aerosol-generating substrate 12. A distal end 18 of the article is defined by the upstream end of the upstream section 16.

[0446] The downstream section 14 of the aerosol-generating article 40 shown in Figure 3 comprises a hollow tubular support element 28, a hollow tubular cooling element 22, and a downstream filter segment 24. The hollow tubular support element 28 is located immediately downstream of the rod 12 of the aerosol-generating substrate. In other words, the hollow tubular support element 28 abuts the downstream end of the rod 12. The hollow tubular cooling element 22 abuts the downstream end of the hollow tubular support element 28, and the downstream filter segment 24 abuts the downstream end of the hollow tubular cooling element 22. Thus, the hollow tubular cooling element 22 is located between the hollow tubular support element 28 and the downstream filter segment 24. The downstream end 19 of the article 40 is defined by the downstream end of the downstream filter segment 24.

[0447] The length of the rod 12 of the aerosol-generating substrate is about 20 mm.

[0448] The hollow tubular support element 28 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The hollow tubular support element 28 defines an interior cavity extending entirely from the upstream end of the hollow tubular support element 28 to the downstream end of the hollow tubular support element 28. The interior cavity is substantially empty, thereby permitting substantially unrestricted airflow along the interior cavity. The hollow tubular support element 28 may not contribute substantially to the overall RTD of the aerosol-generating article 40. The length of the hollow tubular support element 28 is approximately 8 mm. The wall thickness of the hollow tubular support element 28 is approximately 1.5 mm.

[0449] The hollow tubular cooling element 22 is provided in the form of a hollow cylindrical tube made of cardboard or cellulose acetate. The hollow tubular cooling segment 22 defines an interior cavity extending entirely from the upstream end of the hollow tubular cooling element 22 to the downstream end of the hollow tubular cooling element 22. The interior cavity is substantially empty, thereby allowing substantially unrestricted airflow along the interior cavity. The hollow tubular cooling element 22 may not contribute substantially to the overall RTD of the aerosol-generating article 40. The length of the hollow tubular cooling element 22 is approximately 8 mm. The wall thickness of the hollow tubular cooling element 22 is approximately 250 micrometers (μm).

[0450] The downstream filter segment 24 comprises a cylindrical plug of cellulose acetate tow and is approximately 12 mm in length.

[0451] The upstream section 16 comprises an upstream element 341 which abuts the upstream end of the rod 12. The upstream element 341 is provided in the form of a cylindrical plug of cellulose acetate tow. The length of the upstream element 341 is approximately 5 mm.

[0452] The aerosol-generating article 40 includes a ventilation zone 36 provided along the hollow tubular cooling element 22. The ventilation zone 36 includes at least one circumferential row of perforations extending through the peripheral wall of the hollow tubular cooling element 22 and an optional wrapper (not shown) surrounding the hollow tubular cooling element 22. The ventilation zone 36 is provided approximately 2 millimeters from the downstream end of the hollow tubular cooling element 22.

[0453] The aerosol-generating article 40 comprises an elongated susceptor element 44 positioned within the rod 12 of the aerosol-generating substrate. The susceptor element 44 is substantially longitudinally disposed within the rod 12 so as to be generally parallel to the longitudinal direction of the rod 12. When the elongated susceptor element 44 is positioned in thermal contact with the aerosol-generating substrate, the aerosol-generating substrate is heated by the susceptor element 44 when the susceptor element 44 is inductively heated when positioned within a varying electromagnetic field.

[0454] 12, the susceptor element 44 is positioned at a radially central location on the rod and effectively extends along the longitudinal axis of the rod 12. The susceptor element 44 extends completely from the upstream end to the downstream end of the rod 12. In fact, the susceptor element 44 has substantially the same length as the aerosol-generating substrate rod 12.

[0455] The susceptor element 44 may be provided in any of the forms described herein and has a length substantially equal to the length of the rod 12. The upstream section 16 advantageously prevents the susceptor element 44 from becoming dislodged, further ensuring that a consumer cannot accidentally come into contact with the heated susceptor element 44 after use.

[0456] The aerosol-generating article 401 shown in Figure 13 is similar to the aerosol-generating article 40 shown in Figure 12, differing only in that the rod 12 is shorter and the hollow tubular cooling element 22 is longer. In Figure 13, the length of the rod 12 of the aerosol-generating substrate is about 12 mm, and the length of the hollow tubular cooling element 22 is about 25 mm.

[0457] The aerosol-generating article 402 shown in Figure 14 is similar to the aerosol-generating article 40 shown in Figure 12, except that the rod 12 is shorter, the hollow tubular cooling element 22 is longer, and the article 402 further comprises a downstream hollow tubular element 27. In the article 402 shown in Figure 14, the length of the aerosol-generating substrate rod 12 is approximately 12 mm, and the length of the hollow tubular cooling element 22 is approximately 20 mm. Thus, the downstream filter segment 24 is located between the hollow tubular cooling element 22 and the downstream hollow tubular element 27. The downstream end 19 of the article 402 is defined by the downstream end of the downstream hollow tubular element 27.

[0458] The downstream hollow tubular element 27 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The downstream hollow tubular element 27 defines an internal cavity extending entirely from the upstream end of the downstream hollow tubular element 27 to the downstream end of the downstream hollow tubular element 27. The internal cavity is substantially empty, thereby allowing substantially unrestricted airflow along the internal cavity. The downstream hollow tubular element 27 may not contribute substantially to the overall RTD of the aerosol-generating article 402. The length of the downstream hollow tubular element 27 is approximately 5 mm. The wall thickness of the downstream hollow tubular element 27 is approximately 1 mm.

[0459] The aerosol-generating article 403 shown in Figure 15 is similar to the aerosol-generating article 402 shown in Figure 14, except that a ventilation zone 36 is provided along the downstream hollow tubular element 27. The ventilation zone 36 is provided approximately 2 millimeters from the upstream end of the downstream hollow tubular element 27. The ventilation zone 36 comprises at least one circumferential row of perforations extending through the peripheral wall of the downstream hollow tubular element 27 and an optional wrapper (not shown) surrounding the downstream hollow tubular element 27.

[0460] FIG. 16 illustrates an aerosol-generating system 1 comprising an exemplary aerosol-generating device 50 and an aerosol-generating article according to any one of those shown in FIGS. 1-15 and described above.

[0461] 16 illustrates the downstream mouth-end portion of an aerosol generating device 50, in which a device cavity is defined and in which an aerosol-generating article can be received. The aerosol generating device 50 includes a housing (or body) 4 extending between a mouth end 2 and a distal end (not shown). The housing 4 includes a peripheral wall 6. The peripheral wall 6 defines a device cavity for receiving an aerosol-generating article 10. The device cavity is defined by a closed distal end and an open mouth end. The mouth end of the device cavity is located at the mouth end of the aerosol generating device 1. The aerosol-generating article 10 is configured to be received through the mouth end of the device cavity and is configured to abut against the closed end of the device cavity.

[0462] An airflow channel 5 of the device is defined within peripheral wall 6. Airflow channel 5 extends between an inlet 7 located at the mouth end of aerosol-generation device 1 and the closed end of the device cavity. Air may enter aerosol-generation substrate 12 through an opening (not shown) provided in the closed end of the device cavity, ensuring fluid communication between airflow channel 5 and aerosol-generation substrate 12.

[0463] The aerosol-generating device 1 further comprises a heater (not shown) and a power supply (not shown) for supplying power to the heater. A controller (not shown) is also provided for controlling the supply of such power to the heater. The heater is configured to controllably heat the aerosol-generating article during use when the aerosol-generating article is received within the device 1. The heater is preferably arranged to externally heat the aerosol-generating substrate of the aerosol-generating article for optimal aerosol generation. The ventilation zone of the aerosol-generating article is arranged to be exposed when the aerosol-generating article is received within the aerosol-generating device 1.

[0464] For purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like should be understood in all instances to be modified by the term "about." Also, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically recited herein. Thus, in this context, the number A is understood as A ± 10%. Within this context, the number A may be considered to include a numerical value that is within the general standard error for measurement of the property that the number A modifies. In some instances, as used in the appended claims, the number A may deviate by the percentages recited above, provided that the amount by which A deviates does not materially affect the basic and novel characteristics of the claimed invention. Also, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically recited herein.

Claims

1. An aerosol-generating article, comprising: a rod of an aerosol-generating substrate; the aerosol-generating article has a length of at least 60 millimeters; the rod of aerosol-generating substrate has a length of 36 millimeters or less; An aerosol-generating article, wherein the ratio of the length of the rod of the aerosol-generating substrate to the overall length of the aerosol-generating article is 0.4 or less.

2. 2. The aerosol-generating article of claim 1, wherein the rod of aerosol-generating substrate has a length of at least 20 millimeters.

3. 3. The aerosol-generating article of claim 2, wherein the rod of aerosol-generating substrate has a length of at least 25 millimeters.

4. 4. The aerosol-generating article of claim 3, wherein the rod of aerosol-generating substrate has a length of at least 29 millimeters.

5. 5. The aerosol-generating article of claim 4, wherein the rod of aerosol-generating substrate has a length of between 29 millimeters and 36 millimeters.

6. 6. The aerosol-generating article according to claim 1, wherein the ratio of the length of the rod of the aerosol-generating substrate to the overall length of the aerosol-generating article is 0.36 or less.

7. 7. An aerosol-generating article according to any preceding claim, wherein the aerosol-generating article has a length of at least 65 millimeters.

8. 8. An aerosol-generating article according to any preceding claim, wherein the aerosol-generating article has a length of 90 millimeters or less.

9. 9. The aerosol-generating article according to claim 8, wherein the aerosol-generating article has a length of between 65 millimeters and 90 millimeters.

10. 10. The aerosol-generating article according to claim 1, wherein the aerosol-generating article has a maximum outer diameter of 8 millimeters or less.

11. 11. The aerosol-generating article of claim 10, wherein the aerosol-generating article has a maximum outer diameter of between 5 millimeters and 8 millimeters.

12. 12. The aerosol-generating article according to claim 1, wherein the aerosol-generating substrate comprises shredded tobacco material.

13. 13. The aerosol-generating article of claim 12, wherein the cut tobacco material has a bulk density of from 100 milligrams per cubic centimeter to 350 milligrams per cubic centimeter.

14. 14. An aerosol-generating article according to any one of claims 1 to 13, comprising an upstream element provided upstream of the rod of the aerosol-generating substrate and abutting the upstream end of the rod of the aerosol-generating substrate.

15. 1. An aerosol generating system comprising: An aerosol-generating article according to any one of claims 1 to 14, and An aerosol generating system comprising an aerosol generating device comprising a heated chamber for receiving the aerosol-generating article and at least one heating element provided at or near the periphery of the heated chamber.

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