Aerosol generating article having a low-density substrate and a relatively long downstream section

Abstract

The present invention provides an aerosol generating article that can more efficiently heat the aerosol generating substrate when the aerosol generating article is inserted into the heating cavity of the aerosol generating device, thereby minimizing waste of tobacco material. [Solution] An aerosol generating article is provided, comprising a rod of aerosol generating substrate. The aerosol generating article comprises a downstream section provided downstream of the rod of aerosol generating substrate. The rod of aerosol generating substrate contains tobacco material having a bulk density of less than 350 milligrams per cubic centimeter. The downstream section comprises a hollow tubular element that abuts the downstream end of the rod of aerosol generating substrate. The downstream section has a length of at least 40 millimeters.

Description

Technical Field

[0001] The present invention relates to an aerosol article comprising an aerosol generating substrate and adapted to generate an aerosol that can be inhaled upon heating.

Background Art

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

[0003] Numerous prior art documents disclose aerosol generating devices for consuming aerosol articles. Such devices include, for example, an electrically heated aerosol generating device in which an aerosol is generated by heat transfer from one or more electric heater elements of the aerosol generating device to the aerosol generating substrate of the heated aerosol article. For example, an electrically heated aerosol generating device has been proposed that comprises an internal heater blade adapted to be inserted into the aerosol generating substrate. The use of an aerosol article in combination with an external heating system is also known. For example, WO 2020 / 115151 describes the provision of one or more heating elements arranged around the perimeter of an aerosol article when the aerosol article is received within a cavity of an aerosol generating device. Alternatively, an inductively heatable aerosol article comprising an aerosol generating substrate and a susceptor disposed within the aerosol generating substrate has been proposed by WO 2015 / 176898.

Summary of the Invention

[0004] Aerosol-generating articles in which the tobacco-containing substrate is heated rather than burned present numerous challenges not seen in conventional smoking articles. Firstly, the tobacco-containing substrate is typically heated to a significantly lower temperature compared to the temperature reached by the pre-burning portion 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 promote nicotine delivery, the resulting aerosol typically needs to be cooled more widely and rapidly before reaching the consumer. However, technical solutions commonly used in conventional smoking articles to cool the mainstream smoke, such as providing a highly filtration-efficient segment at the mouth-end of the cigarette, may have undesirable effects in aerosol-generating articles in which the tobacco-containing substrate is heated rather than burned, as this can reduce nicotine delivery. Consequently, it is desirable to provide novel aerosol-generating articles that can consistently ensure satisfactory aerosol delivery to the consumer.

[0005] Furthermore, there is a general need for aerosol generating articles that are easier to use and have improved practicality. For example, it is 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 held securely within the heating cavity so as not to slip out during use.

[0006] It is even more desirable to provide an aerosol generating article that is adapted to more efficiently heat the aerosol generating substrate when the aerosol generating article is inserted into the heating cavity of the aerosol generating device, thereby minimizing the waste of tobacco material. [Brief explanation of the drawing]

[0007] [Figure 1]This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 2] This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 3a] This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 3b] This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 4a] This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 4b] This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 5] This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 6] This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 7] This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 8] This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 9] This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 10] This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 11] This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 12] This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 13] This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 14] This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 15] This disclosure shows a schematic side cross-sectional view of the aerosol-generating article. [Figure 16] This diagram shows a schematic side cross-sectional view of an aerosol generating system comprising an aerosol generating device and an aerosol generating article according to this disclosure. [Modes for carrying out the invention]

[0008] This 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 also comprise a downstream section provided downstream of the rod of the aerosol-generating substrate. The aerosol-generating substrate may contain tobacco material having a bulk density of less than 350 milligrams per cubic centimeter. The downstream section may comprise a hollow tubular element that abuts the downstream end of the rod of the aerosol-generating substrate. The downstream section may have a length of at least 40 millimeters.

[0009] According to the present invention, an aerosol generating article is provided comprising a rod of an aerosol generating substrate. The aerosol generating article comprises a downstream section provided downstream of the rod of the aerosol generating substrate. The rod of the aerosol generating substrate contains tobacco material having a bulk density of less than 350 milligrams per cubic centimeter. The downstream section comprises a hollow tubular element that abuts the downstream end of the rod of the aerosol generating substrate. The downstream section has a length of at least 40 millimeters.

[0010] The present invention relates to an aerosol generating article having a rod of aerosol generating substrate with a relatively low bulk density and a relatively long downstream section. Prior art aerosol generating articles may have a rod of aerosol generating substrate with a relatively high bulk density and a shorter downstream section. Therefore, the present invention provides a structure that is significantly different from the prior art aerosol generating article.

[0011] The rod of the aerosol generating substrate may generate an aerosol upon heating, for example, by an aerosol generating device. The resulting generated aerosol can be at a high temperature and can be very uncomfortable for the user if the aerosol is delivered to the user immediately after generation. Thus, some aerosol generating articles provide a space for the aerosol to cool after aerosol generation and before the aerosol is delivered 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.

[0012] By providing a relatively long aerosol generating article, the total length of the path that the generated aerosol travels within and through the downstream section of the aerosol generating article can be increased before the aerosol is delivered to the user. By increasing the total length of the path that the aerosol travels before being delivered to the user, the aerosol can be cooled and the time for the temperature to decrease can be lengthened before being delivered to the user.

[0013] A high-density aerosol generating substrate may not be fully heated and consumed during the heating cycle of the article, especially in situations where it is externally heated, and may increase the draw resistance (RTD) of the article. As a result, this can lead to a situation where a portion of the aerosol generating substrate is not effectively heated to contribute to the generation of the aerosol. This portion of the aerosol generating substrate may effectively be wasted.

[0014] Therefore, providing both a reduced density substrate and a relatively long downstream section advantageously improves the holding characteristics of articles within the heating device, provides a lower temperature aerosol to the user while minimizing waste of the substrate, and can provide a lower temperature aerosol to the user. By providing a relatively long downstream section having a hollow tubular element, a longer portion of the downstream section can engage the heating chamber of the heating device, thus improving the holding of the aerosol-generating article within the heating chamber of the aerosol-generating device. Providing a substrate with a relatively low bulk density minimizes the likelihood that the aerosol-generating article will not generate aerosol, thereby potentially reducing manufacturing costs and waste. Further, the low density substrate can advantageously be heated more quickly during use so that aerosol can be generated earlier within the heating cycle of the article.

[0015] Therefore, for example, in order to maximize the ratio of the rod of the aerosol-generating substrate that is heated when the aerosol-generating article is inserted into the heating cavity of the aerosol-generating device, while ensuring effective cooling of the aerosol flowing downstream from the substrate, it may be desirable to have a rod of a low density aerosol-generating substrate with an increased length downstream section. This may then optimize the efficiency of aerosol generation from the rod of the aerosol-generating substrate, such that the amount of aerosol-generating substrate can be minimized as much as possible without affecting the generation of aerosol and the RTD characteristics of the article, whereas otherwise it could undesirably increase by providing a longer rod. The amount of aerosol-generating substrate that is effectively wasted because it is not used to generate aerosol 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 in conjunction with existing aerosol-generating devices. It may also be important that existing machinery and packaging can be used without requiring modification.

[0016] The aerosol generating article according to the present invention comprises a rod of an 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, one or more elements downstream of the rod of the aerosol generating substrate form the downstream section of the aerosol generating article. The aerosol generating article according to the present invention may comprise one or more elements provided upstream of the aerosol generating substrate. If present, one or more elements upstream of the rod of the aerosol generating substrate form the upstream section of the aerosol generating article.

[0017] The rod of the aerosol generating substrate is preferably surrounded by a wrapper such as a plug wrap.

[0018] The rod of the aerosol generating substrate preferably has a length of at least 10 millimeters. The rod of the aerosol generating substrate preferably has a length of at least 15 millimeters. The rod of the aerosol generating substrate more preferably has a length of at least 17 millimeters. The rod of the aerosol generating substrate is even more preferably has a length of at least 18 millimeters. The rod of the aerosol generating substrate most preferably has a length of at least 20 millimeters.

[0019] The rod of the aerosol generating substrate is preferably less than 40 millimeters in length. It is preferable that the rod of the aerosol generating substrate is less than 35 millimeters in length. More preferably, the rod of the aerosol generating substrate is less than 30 millimeters in length.

[0020] 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.

[0021] The rod of the aerosol generating substrate preferably has an outer diameter that is approximately equal to the outer diameter of the aerosol generating article.

[0022] 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.

[0023] The rod of the aerosol generating substrate preferably has an outer diameter of at least about 5 mm. More preferably, the rod of the aerosol generating substrate has an outer diameter of at least 5.25 mm. Even more preferably, the rod of the aerosol generating substrate has an outer diameter of at least 5.5 mm.

[0024] The rod of the aerosol generating substrate preferably has an outer diameter of less than 8 mm. More preferably, the rod of the aerosol generating substrate has an outer diameter of less than 7.5 mm. Even more preferably, the rod of the aerosol generating substrate has an outer diameter of less than 7 mm.

[0025] Generally, it has been observed that the smaller the diameter of the rod of an aerosol-generating substrate, the lower the temperature required to raise the core temperature of the 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, although we do not wish to be bound by theory, it is understood that the smaller the diameter of the rod of an aerosol-generating substrate, the faster the heat supplied to the aerosol-generating article can penetrate the total volume of the aerosol-generating substrate. Nevertheless, if the diameter of the rod of the aerosol-generating substrate is too small, the volume-to-surface area ratio of the aerosol-generating substrate becomes undesirable as the amount of available aerosol-generating substrate decreases.

[0026] The diameter of the aerosol generating substrate rods within the range described herein is particularly advantageous in terms of the balance between energy consumption and aerosol delivery. This advantage is particularly evident when an aerosol generating article having an aerosol generating substrate rod having the diameter described herein is used in combination with an external heater positioned around the aerosol generating article. Under such operating conditions, it has been observed that less thermal energy is required to achieve a sufficiently high temperature in the core of the aerosol generating substrate rod, and generally in the core of the article. Therefore, when operating at lower temperatures, the desired target temperature in the core of the aerosol generating substrate may be achieved within a desirablely reduced time frame and with less energy consumption.

[0027] Using a rod of aerosol-generating substrate with a smaller diameter also has the advantage of being able to reduce the overall weight of tobacco material required for the aerosol-generating article while still being able to generate the desired level of aerosol. Thus, the level of tobacco waste can be reduced.

[0028] Preferably, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is at least 0.20. Preferably, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is at least 0.25. More preferably, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is at least 0.30.

[0029] The ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is preferably less than 0.50. The ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is preferably less than 0.45. More preferably, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is less than 0.40.

[0030] 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 yet another embodiment, 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 another embodiment, 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.

[0031] The rod of the aerosol generating substrate preferably has a substantially uniform cross-section along its length. It is particularly preferable that the rod of the aerosol generating substrate has a substantially circular cross-section.

[0032] 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.

[0033] 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.

[0034] For example, the density of the aerosol generating substrate is preferably 100 mg to 1000 mg per cubic centimeter, preferably 100 mg to 800 mg per cubic centimeter, more preferably 100 mg to 700 mg per cubic centimeter, more preferably 100 mg to 600 mg per cubic centimeter, more preferably 100 mg to 500 mg per cubic centimeter, and even more preferably 100 mg to 400 mg per cubic centimeter.

[0035] For example, the density of the aerosol generating substrate is preferably 100 mg to 350 mg per cubic centimeter, preferably 100 mg to 345 mg per cubic centimeter, preferably 125 mg to 325 mg per cubic centimeter, more preferably 150 mg to 300 mg per cubic centimeter, more preferably 150 mg to 290 mg per cubic centimeter, and even more preferably 200 mg to 280 mg per cubic centimeter.

[0036] The aerosol generating substrate may contain tobacco material. The rod of the aerosol generating substrate may contain tobacco material. The tobacco material may contain shredded tobacco material. The shredded tobacco material may be in the form of cut filler or tobacco cut filler.

[0037] The tobacco material preferably 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. The tobacco material preferably 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 to 350 milligrams per cubic centimeter, preferably 100 milligrams to 345 milligrams per cubic centimeter, more preferably 125 milligrams to 325 milligrams per cubic centimeter, more preferably 150 milligrams to 300 milligrams per cubic centimeter, more preferably 150 milligrams to 290 milligrams per cubic centimeter, and even more preferably 200 milligrams to 280 milligrams per cubic centimeter.

[0038] As used herein in relation to aerosol-generating substrates, the term "density" refers to the bulk density of the aerosol-generating substrate. This can be calculated by measuring the total weight of the aerosol-generating substrate and dividing it by the volume of the rod of the aerosol-generating substrate (excluding the wrapper).

[0039] The bulk density of tobacco material in an aerosol generating substrate can be calculated by dividing the total mass of tobacco material in the rods of the aerosol generating substrate by the volume of the aerosol generating substrate (excluding the wrapper). The mass of tobacco material in an aerosol generating substrate can be determined by removing the tobacco material from the aerosol generating substrate and weighing it. The bulk density of tobacco material in an aerosol generating substrate may also be determined after preparing the aerosol generating substrate according to ISO standard 3402:1999.

[0040] The aerosol generating substrate may contain shredded tobacco material. The rod of the aerosol generating substrate may contain shredded tobacco material. The shredded tobacco material may be in the form of cut filler or tobacco cut filler. The density of such aerosol generating substrate or shredded tobacco material may be as follows:

[0041] In certain preferred embodiments, the aerosol generating substrate rod comprises shredded tobacco material, such as tobacco cut filler, with 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. The aerosol generating substrate rod preferably comprises shredded tobacco material having a bulk density of at least 100 mg per cubic centimeter. It is more preferable that the aerosol generating substrate rod comprises shredded tobacco material having a bulk density of at least 125 mg per cubic centimeter. It is even more preferable that the aerosol generating substrate rod comprises shredded tobacco material having a bulk density of at least 150 mg per cubic centimeter. It is even more preferable that the aerosol generating substrate rod comprises shredded tobacco material having a bulk density of at least 200 mg per cubic centimeter. For example, the rod of the aerosol generating substrate may contain shredded tobacco material having a density of 100 mg to 350 mg per cubic centimeter, preferably 100 mg to 345 mg per cubic centimeter, preferably 125 mg to 325 mg per cubic centimeter, more preferably 150 mg to 300 mg per cubic centimeter, more preferably 150 mg to 290 mg per cubic centimeter, and even more preferably 200 mg to 280 mg per cubic centimeter.

[0042] The RTD of the aerosol generating substrate rod is preferably less than approximately 10 mmH2O. More preferably, the RTD of the aerosol generating substrate rod is less than 9 mmH2O. Even more preferably, the RTD of the aerosol generating substrate rod is less than 8 mmH2O.

[0043] The RTD of the aerosol generating substrate rod is preferably at least 4 mmH2O. More preferably, the RTD of the aerosol generating substrate rod is at least 5 mmH2O. Even more preferably, the RTD of the aerosol generating substrate rod is at least 6 mmH2O.

[0044] In some embodiments, the RTD of the aerosol-generating substrate rod is 4 mmH2O to 10 mmH2O, preferably 5 mmH2O to 10 mmH2O, and preferably 6 mmH2O to 25 mmH2O. In other embodiments, the RTD of the aerosol-generating substrate rod is 4 mmH2O to 20 mmH2O, preferably 5 mmH2O to 18 mmH2O, and preferably 6 mmH2O to 16 mmH2O. In further embodiments, the RTD of the aerosol-generating substrate rod is 4 mmH2O to 15 mmH2O, preferably 5 mmH2O to 14 mmH2O, and more preferably 6 mmH2O to 12 mmH2O.

[0045] The aerosol generating substrate may be a solid aerosol generating substrate. Preferably, the aerosol generating substrate includes an aerosol forming agent. The aerosol forming agent can be any suitable known compound or mixture of compounds that promotes the formation of a dense and stable aerosol during use. The aerosol forming agent can promote the aerosol to be substantially resistant to thermal decomposition at the temperatures typically applied during use of the aerosol generating article. Suitable aerosol forming agents 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 dodecanediol, dimethyl tetradecanediol, etc.), and combinations thereof.

[0046] The aerosol-forming body preferably contains one or more of glycerin and propylene glycol. The aerosol-forming body may consist of glycerin, propylene glycol, or a combination of glycerin and propylene glycol.

[0047] The aerosol generating substrate preferably contains at least 5 weight percent of aerosol-forming material based on the dry weight of the aerosol generating substrate, more preferably at least 6 weight percent of aerosol-forming material based on the dry weight of the aerosol generating substrate, and at least 8 weight percent of aerosol-forming material based on the dry weight of the aerosol generating substrate.

[0048] The aerosol generating substrate preferably contains less than 90 weight percent of aerosol-forming material based on the dry weight of the aerosol generating substrate, more preferably less than 80 weight percent of aerosol-forming material based on the dry weight of the aerosol generating substrate, more preferably less than 70 weight percent of aerosol-forming material based on the dry weight of the aerosol generating substrate, more preferably less than 60 weight percent of aerosol-forming material based on the dry weight of the aerosol generating substrate, more preferably less than 50 weight percent of aerosol-forming material based on the dry weight of the aerosol generating substrate, and more preferably less than 40 weight percent of aerosol-forming material based on the dry weight of the aerosol generating substrate.

[0049] The aerosol generating substrate preferably contains less than 30 weight percent of aerosol-forming material on a dry weight basis of the aerosol generating substrate, more preferably less than 25 weight percent of aerosol-forming material on a dry weight basis of the aerosol generating substrate, and more preferably less than 20 weight percent of aerosol-forming material on a dry weight basis of the aerosol generating substrate.

[0050] For example, the aerosol generating substrate may contain 5% to 30% by weight of aerosol-forming material based on the dry weight of the aerosol generating substrate, more preferably 6% to 25% by weight of aerosol-forming material based on the dry weight of the aerosol generating substrate, and more preferably 10% to 20% by weight of aerosol-forming material based on the dry weight of the aerosol generating substrate.

[0051] For example, the aerosol generating substrate may preferably contain 5% to 30% by weight of glycerin, more preferably 6% to 25% by weight of glycerin, and more preferably 10% to 20% by weight of 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 fillers, as will be described in more detail below. Alternatively, the shredded tobacco material may be in the form of shredded sheets of homogenized tobacco material. Suitable homogenized tobacco materials for use in the present invention are described below.

[0052] In the context of this specification, the term “cut filler” is used to describe a blend of finely chopped plant materials, such as tobacco plant material, which specifically includes one or more of the following: leaf blades, processed stems and veins, and homogenized plant material.

[0053] Cut fillers may also include other cut pieces, filler tobacco, or outer covering.

[0054] 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 clove. The plant material is most preferably tobacco. However, as will be discussed in more detail below, the present invention is equally applicable to other plant materials having the ability to release a substance that can subsequently form an aerosol upon application of heat.

[0055] The cut filler preferably contains tobacco plant material, including one or more leaf blades from bright tobacco, dark tobacco, aromatic tobacco, and filler tobacco. In relation to the present invention, the term "tobacco" refers to any plant of the genus Nicotiana.

[0056] Bright tobacco is generally tobacco with large, light-colored leaves. Throughout this specification, the term “bright tobacco” is used for fully cured tobacco. Examples of bright tobacco include fully cured tobacco from China, fully cured tobacco from Brazil, fully cured tobacco from the United States (such as Virginia tobacco), fully cured tobacco from India, fully cured tobacco from Tanzania, or other fully cured tobacco from Africa. Bright tobacco is characterized by a high sugar-to-nitrogen ratio. From a sensory perspective, bright tobacco is a type of tobacco that, after curing, has a spicy and lively feel. In the context of this invention, bright tobacco is tobacco in which the reducing sugar content is about 2.5 percent to about 20 percent on a dry weight basis of the leaves, and the total ammonia content is less than about 0.12 percent on a dry weight basis of the leaves. Reducing sugars include, for example, glucose or fructose. Total ammonia includes, for example, ammonia and ammonium salts.

[0057] Dark tobacco is tobacco that generally has large, dark-colored leaves. Throughout this specification, the term “dark tobacco” is used for air-cured tobacco. Additionally, dark tobacco may be fermented. Tobacco used primarily for chewing tobacco, snuff, cigar tobacco, and pipe blends also falls into this category. Typically, these dark tobaccos are air-cured and, in some cases, fermented. From a sensory perspective, dark tobacco is a type of tobacco that, after curing, has a smoky, dark cigar-like sensation. Dark tobacco is characterized by a low sugar-to-nitrogen ratio. Examples of dark tobacco include Burley Malawi or other African Burley, dark-cured Brazil Galpao, Sun-Cure, or air-cured Indonesian Kasturi. According to the present invention, dark tobacco is tobacco in which the reducing sugar content is less than about 5 percent on a dry weight basis of the leaves, and the total ammonia content is less than or equal to about 0.5 percent on a dry weight basis of the leaves.

[0058] Aromatic tobacco is tobacco that often has small, light-colored leaves. Throughout this specification, the term “aromatic tobacco” is used in reference to other tobaccos that have a high content of aromatic compounds, such as essential oils. From a sensory perspective, aromatic tobacco is a type of tobacco that, after curing, has a spicy and aromatic sensation. Examples of aromatic tobaccos include Greek Orient, Oriental Turkish, and Semi-Oriental tobaccos, but also US Burley, Rustica, or Maryland, such as Fire-Cured Perique. Filler tobacco is not a specific type of tobacco, but includes tobacco types that are primarily used to complement other tobacco types used in blends and do not give the final product a specific characteristic aromatic direction. Examples of filler tobacco are the stems, midribs, or petioles of other tobacco types. A specific example may be the hot-air-dried stems of the lower petioles of Brazilian hot-air-dried petioles.

[0059] The cut filler suitable for use in the present invention may generally be similar to the cut fillers used in conventional smoking articles. The cutting 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 cutting width may play a role in the heat distribution inside the rod of the aerosol generating substrate. The cutting width may also play a role in the resistance to pulling out the article. Furthermore, overall, the cutting width may affect the overall density of the aerosol generating substrate.

[0060] Since the strand length depends on the overall size of the object from which the strand is cut, the strand length of the cut filler is somewhat random. Nevertheless, longer strands can be cut by conditioning the material before cutting, for example, by controlling the moisture content and overall delicacy of the material. Preferably, the strands have a length of about 10 mm to about 40 mm, and then the strands are arranged to form a rod of aerosol generating substrate. Naturally, if the strands are arranged within the rod of the aerosol generating substrate in the longitudinal extension of the section which is less than 40 mm, the final rod of the aerosol generating substrate may contain strands that are, on average, shorter than the initial strand length. Preferably, the strand length of the cut filler is such that about 20 percent to 60 percent of the strand extends along the entire length of the rod of the aerosol generating substrate. This prevents the strand from easily coming off the rod of the aerosol generating substrate.

[0061] In a preferred embodiment, the weight of the cut filler is 80 to 400 milligrams, preferably 150 to 250 milligrams, and more preferably 170 to 220 milligrams. This amount of cut filler is typically sufficient material for aerosol formation. Additionally, in light of the aforementioned constraints on diameter and size, this allows for a balanced density of the rod of the aerosol-generating substrate between energy uptake, draw resistance, and fluid passages within the rod of the aerosol-generating substrate, when the aerosol-generating substrate contains plant material.

[0062] The cut filler is preferably immersed in an aerosol-forming agent. Immersion of the cut filler can be carried out by spraying or other suitable application methods. The aerosol-forming agent can be added to the blend during the preparation of the cut filler. For example, the aerosol-forming agent may be applied directly to the blend in the conditioning casing cylinder (DCCC). Conventional machinery can be used to add the aerosol-forming agent to the cut filler. The aerosol-forming agent can be any suitable known compound or mixture of compounds that promotes the formation of a dense and stable aerosol at the time of use. The aerosol-forming agent can promote the aerosol's substantial resistance to thermal decomposition at the temperatures typically applied during the use of the aerosol-generating article. Suitable aerosol-forming agents include, for example, polyhydric alcohols (e.g., triethylene glycol, 1,3-butanediol, propylene glycol, and glycerin), esters of polyhydric alcohols (e.g., glycerol monoacetate, diacetate, or triacetate), aliphatic esters of monocarboxylic acids, dicarboxylic acids, or polycarboxylic acids (e.g., dimethyl dodecanediate and dimethyl tetradecanediate), and combinations thereof.

[0063] The aerosol-forming body preferably contains one or more of glycerin and propylene glycol. The aerosol-forming body may consist of glycerin, propylene glycol, or a combination of glycerin and propylene glycol.

[0064] Preferably, the amount of aerosol-forming material is at least 5% by weight on a dry weight basis, preferably 5% to 30% by weight on a dry weight basis of the cut filler, and more preferably 6% to 20% by weight on a dry weight basis of the cut filler, for example, the amount of aerosol-forming material is 8% to 15% by weight on a dry weight basis of the cut filler. When the aerosol-forming material is added to the cut filler in the above amounts, the cut filler may become relatively sticky. This is advantageous because the cut filler particles tend to adhere not only to the surrounding cut filler particles but also to the surrounding surface (e.g., the inner surface of the wrapper surrounding the cut filler), thus helping to hold the cut filler in place within the article.

[0065] In some embodiments, the amount of aerosol former has a target value of about 13 weight percent on a dry weight basis of the cut filler. The most efficient amount of aerosol former also depends on the cut filler, and whether the cut filler contains plant laminas or homogenized plant material. For example, among other factors, the type of cut filler determines to what extent the aerosol former can facilitate the release of material from the cut filler.

[0066] For these reasons, a rod of an aerosol generating substrate equipped with the cut filler described above has the ability to efficiently generate a sufficient amount of aerosol at relatively low temperatures. A temperature of 150 to 200 degrees Celsius in the heating chamber may be sufficient for one such cut filler to generate a sufficient amount of aerosol, while a temperature of approximately 250 degrees Celsius is typically employed in aerosol generators using tobacco cast leaf sheets.

[0067] A further advantage associated with operating at lower temperatures is the reduced need to cool the aerosol. Since generally lower temperatures are used, simpler cooling mechanisms may suffice. This, in turn, allows for the use of simpler and more basic structures in aerosol-generating articles.

[0068] In other preferred embodiments, the aerosol-generating substrate includes homogenized plant material, preferably homogenized tobacco material.

[0069] As used herein, the term “homogenized plant material” encompasses any plant material formed by the aggregation of plant particles. For example, a sheet or web of homogenized tobacco material for the aerosol-generating substrate of the present invention may be formed by aggregating plant material and, optionally, one or more tobacco leaf laminas and tobacco leaf stems, which are obtained by grinding, crushing, or pulverizing tobacco material particles. The homogenized plant material may be produced by casting, extrusion, papermaking processes, or any other suitable process known in the art.

[0070] Homogenized plant material can be provided in any suitable form.

[0071] In some embodiments, the homogenized plant material may be in the form of one or more sheets. As used herein in relation to the present invention, the term “sheet” refers to a thin layer having a width and length considerably greater than its thickness.

[0072] The homogenized plant material may be in the form of multiple pellets or granules.

[0073] Homogenized plant material may be in the form of multiple strands, strips, or fragments. As used herein, the term “strand” describes an elongated element of the material having a length substantially greater than its width and thickness. The term “strand” should be considered to encompass strips, fragments, and any other homogenized plant material having a similar form. Strands of homogenized plant material may be formed from a sheet of homogenized plant material, for example, by cutting or dicing, or by other means, such as by extrusion.

[0074] In some embodiments, strands may be formed in situ within the aerosol-generating substrate as a result of the splitting or decomposition of a sheet of homogenized plant material during the formation of the aerosol-generating substrate, for example, as a result of crimping. The strands of homogenized plant material within the aerosol-generating substrate may be separated from each other. Alternatively, each strand of homogenized plant material within the aerosol-generating substrate may be at least partially connected to adjacent strands along the length of the strand. For example, adjacent strands may be connected by one or more fibers. This may occur, for example, when strands are formed as a result of the splitting of a sheet of homogenized plant material during the manufacture of the aerosol-generating substrate, as described above.

[0075] As described above, if the homogenized plant material is in the form of one or more sheets, the sheets may be manufactured by a casting process. Alternatively, the sheets of homogenized plant material may be manufactured by a papermaking process.

[0076] Each of the one or more sheets described herein may individually have a thickness of 100 to 600 micrometers, preferably 150 to 300 micrometers, and most preferably 200 to 250 micrometers. Individual thickness refers to the thickness of an individual sheet, while combined thickness refers to the total thickness of all sheets constituting 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, which are stacked within the aerosol generating substrate.

[0077] Each of the sheets described herein may individually have a basis weight of 100 grams per square meter to 600 grams per square meter.

[0078] Each of the sheets described herein may individually have a density of 0.3 grams to 1.3 grams per cubic centimeter, preferably 0.7 grams to 1.0 gram per cubic centimeter.

[0079] In embodiments of the present invention, the aerosol generating substrate comprises one or more sheets of homogenized plant material, the sheets are preferably in the form of an aggregate of one or more sheets. As used herein, the term “aggregate” means that the sheets of homogenized plant material are spiraled, folded, or otherwise compressed or shrunk substantially transversely to the cylindrical axis of a plug or rod.

[0080] One or more sheets of homogenized plant material may be assembled transversely to their longitudinal axis and surrounded by a wrapper to form a continuous rod or plug.

[0081] 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 multiple substantially parallel ridges or undulations. 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.

[0082] Preferably, one or more sheets of homogenized plant material can be crimped to have a plurality of ridges or undulations substantially parallel to the cylindrical axis of the plug. This process advantageously facilitates the assembly of the crimped sheets of homogenized plant material to form the plug. Preferably, one or more sheets of homogenized plant material can be assembled. Naturally, the crimped sheets of homogenized plant material may, by other means or additionally, have a plurality of substantially parallel ridges or undulations that form acute or obtuse angles with respect to the cylindrical axis of the plug. The sheets may be crimped to such an extent that the integrity of the sheet is interrupted at the plurality of parallel ridges or undulations, causing separation of the material and resulting in the formation of fragments, strands, or shards of homogenized plant material.

[0083] One or more sheets of homogenized plant material may be cut into strands as mentioned above. In such embodiments, the aerosol-generating substrate comprises several strands of homogenized plant material. The strands may be used to form a plug. Typically, the width of such strands is about 5 millimeters, or about 4 millimeters, or about 3 millimeters, or about 2 millimeters, or less. The length of the strands may be longer than about 5 millimeters, or about 5 millimeters to about 15 millimeters, or about 8 millimeters to about 12 millimeters, or about 12 millimeters. Preferably, the strands are substantially the same length as each other.

[0084] The homogenized plant material may contain up to about 95 weight percent of plant particles on a dry weight basis. Preferably, the homogenized plant material contains up to 90 weight percent of plant particles, more preferably up to 80 weight percent of plant particles, more preferably up to 70 weight percent of plant particles, more preferably up to 60 weight percent of plant particles, and more preferably up to about 50 weight percent of plant particles on a dry weight basis.

[0085] For example, homogenized plant material may contain, on a dry weight basis, 2.5 to 95 percent by weight of plant particles, or 5 to 90 percent by weight of plant particles, or 10 to 80 percent by weight of plant particles, or 15 to 70 percent by weight of plant particles, or 20 to 60 percent by weight of plant particles, or 30 to 50 percent by weight of plant particles.

[0086] In certain embodiments of the present invention, the homogenized plant material is a homogenized tobacco material containing tobacco particles. The sheets of homogenized tobacco material used in these embodiments of the present invention may have a tobacco content of at least about 40 weight percent, more preferably at least about 50 weight percent, more preferably at least about 70 weight percent, and most preferably at least about 90 weight percent, on a dry weight basis.

[0087] In relation to the present invention, the term “tobacco particles” refers to particles of any plant material of the Nicotiana species. The term “tobacco particles” includes crushed or powdered tobacco leaf lamina, crushed or powdered tobacco leaf stems, tobacco dust, tobacco fine powder, and other particulate tobacco by-products formed during the processing, handling, and shipping of tobacco. In preferred embodiments, tobacco particles are substantially all derived from tobacco leaf lamina. In contrast, separated nicotine and nicotine salts, although compounds derived from tobacco, are not considered tobacco particles for the purposes of the present invention and are not included in the proportion of particulate plant material.

[0088] The homogenized plant material may further contain one or more aerosol-forming bodies. As they volatilize, the aerosol-forming bodies can carry other vaporized compounds released from the aerosol-generating substrate upon heating, such as nicotine and flavorings in the aerosol. Suitable aerosol-forming bodies 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 (glycerol mono-, di-, or triacetate), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dodecanedioic acid and dimethyl tetradecanedioic acid).

[0089] The homogenized plant material may contain an aerosol-forming agent content of 5% to 30% by dry weight (10% to 25% by dry weight, or 15% to 20% by dry weight, etc.). The aerosol-forming agent may act as a wetting agent in the homogenized plant material.

[0090] In certain embodiments, the aerosol generating article further comprises a susceptor element within a rod of the aerosol generating substrate. For example, an elongated susceptor element may be substantially axially positioned within the rod of the aerosol generating substrate and be in thermal contact with the aerosol generating substrate.

[0091] As used herein in relation to the present invention, the term "susceptor element" refers to a material capable of converting electromagnetic energy into heat. When located in a fluctuating electromagnetic field, induced eddy currents in the susceptor element cause heating of the susceptor element. Since the susceptor element is located in thermal contact with the aerosol-generating substrate, the aerosol-generating substrate is heated by the susceptor element.

[0092] 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 thickness dimension, for example, greater than twice its width dimension or thickness dimension.

[0093] The susceptor element is positioned substantially along the longitudinal axis within the rod. This means that the length dimension of the elongated susceptor element is positioned approximately parallel to the longitudinal direction of the rod, for example, within ±10 degrees from parallel to the longitudinal direction of the rod. In a preferred embodiment, the elongated susceptor element may be positioned radially centrally within the rod and extend along the longitudinal axis of the rod.

[0094] Preferably, the susceptor element extends over the entire length of the rod of the aerosol generating substrate. In some embodiments, the susceptor element may extend over the entire length of the rod of the aerosol generating substrate. In a particularly preferred embodiment, the susceptor element has substantially the same length as the rod of the aerosol generating substrate and extends from the upstream end of the rod to the downstream end of the rod.

[0095] The susceptor element is preferably in the form of a pin, rod, strip, or blade.

[0096] The susceptor element preferably has a length of 10 mm to 40 mm, for example, 15 mm to 35 mm, or 17 mm to 30 mm.

[0097] The susceptor element preferably has a length of 5 mm to 15 mm, for example, 6 mm to 12 mm, or 8 mm to 10 mm.

[0098] The susceptor element preferably has a width of 1 mm to 5 mm.

[0099] The susceptor element can generally have a thickness of 0.01 mm to 2 mm, for example, 0.5 mm to 2 mm. In some embodiments, the susceptor element preferably has a thickness of 10 micrometers to 500 micrometers, more preferably 10 micrometers to 100 micrometers.

[0100] If the susceptor element has a certain cross-section, for example a circular cross-section, it has a preferred width or diameter of 1 to 5 millimeters.

[0101] If the susceptor element has the form of a strip or blade, the strip or blade has a rectangular shape, preferably with a width of 2 to 8 mm, more preferably 3 to 5 mm. As an example, a susceptor element in the form of a blade strip may have a width of 4 mm.

[0102] If the susceptor element has the form of a strip or blade, the strip or blade is preferably rectangular in shape and has a thickness of 0.03 mm to 0.15 mm, more preferably 0.05 mm 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.

[0103] In a preferred embodiment, the elongated susceptor element is in the form of a strip or blade, preferably having a rectangular shape and a thickness of 55 to 65 micrometers.

[0104] More preferably, the elongated susceptor element has a thickness of 57 to 63 micrometers. Even more preferably, the elongated susceptor element has a thickness of 58 to 62 micrometers. In a particularly preferred embodiment, the elongated susceptor element has a thickness of 60 micrometers.

[0105] The elongated susceptor element is preferably the same length as or shorter than the aerosol-generating substrate.

[0106] The susceptor element can be formed from any material that can be inductively heated to a temperature sufficient to generate aerosols from the aerosol-generating substrate. Preferred susceptor elements include metals or carbon.

[0107] Preferred susceptor elements may include or consist of ferromagnetic materials such as ferromagnetic alloys, ferrite iron, or ferromagnetic steel or stainless steel. Suitable susceptor elements may be aluminum or contain aluminum. Preferred susceptor elements may be formed from 400 series stainless steel, such as grade 410, or grade 420, or grade 430 stainless steel. Different materials dissipate different amounts of energy when positioned in an electromagnetic field having similar values ​​of frequency and magnetic field strength.

[0108] Thus, any of the parameters of the susceptor element, such as the type of material, length, width, and thickness, can be varied to provide the desired power distribution within a known electromagnetic field. A preferred susceptor element may be heated to a temperature above 250 degrees Celsius.

[0109] A suitable susceptor element may comprise a non-metallic core on which a metal layer, such as a metal strip formed on the surface of a ceramic core, is arranged. The susceptor element may have a protective outer layer enclosing it, such as a protective ceramic layer or a protective glass layer. The susceptor element may also comprise a protective coating formed of glass, ceramic, or an inert metal, formed on the core of the susceptor element material.

[0110] The susceptor element is disposed in thermal contact with the aerosol generating substrate. Thus, when the temperature of the susceptor element rises, the aerosol generating substrate is heated, and an aerosol is formed. Preferably, the susceptor element is disposed, for example, within the aerosol generating substrate, in direct physical contact with the aerosol generating substrate.

[0111] As shown above, the rods of the aerosol generating substrate may be surrounded by a wrapper. The wrapper surrounding the rods of the aerosol generating substrate may be a paper wrapper or a non-paper wrapper. Suitable paper wrappers for use in specific embodiments of the present invention are known in the art and include, but are not limited to, cigarette papers and filter plug wrappers. Suitable non-paper wrappers for use in specific embodiments of the present invention are known in the art and include, but are not limited to, sheets of homogenized tobacco material.

[0112] 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, 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, 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, more preferably 35 micrometers to 45 micrometers. In a preferred embodiment, the paper wrapper may have a thickness of 40 microns.

[0113] In certain preferred embodiments, the wrapper may be formed from a laminated material comprising multiple layers. Preferably, the wrapper is formed from an aluminum co-laminate sheet. The use of an aluminum co-laminate sheet is advantageous in that it prevents combustion of the aerosol-generating substrate when the aerosol-generating substrate is to be ignited rather than heated in the intended manner.

[0114] The paper layer of the co-laminated sheet may have a basis weight of at least 35 gsm, preferably at least 40 gsm. The paper layer of the co-laminated sheet may have a basis weight of 55 gsm or less, preferably 50 gsm or less. The paper layer of the co-laminated 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-laminated sheet may have a basis weight of 45 gsm.

[0115] The paper layer of the co-laminated sheet may have a thickness of at least 50 micrometers, preferably at least 55 micrometers, and more preferably at least 60 micrometers. The paper layer of the co-laminated sheet may have a thickness of 80 micrometers or less, preferably 75 micrometers or less, and more preferably 70 micrometers or less.

[0116] The paper layer of the co-laminated 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-laminated sheet may have a thickness of 65 microns.

[0117] The metal layer of the co-laminated sheet may have a basis weight of at least 12 gsm, preferably at least 15 gsm. The metal layer of the co-laminated sheet may have a basis weight of 25 gsm or less, preferably 20 gsm or less. The metal layer of the co-laminated 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-laminated sheet may have a basis weight of 17 gsm.

[0118] The metal layer of the co-laminated sheet may have a thickness of at least 2 micrometers, preferably at least 3 micrometers, and more preferably at least 5 micrometers. The metal layer of the co-laminated sheet may have a thickness of 15 micrometers or less, preferably 12 micrometers or less, and more preferably 10 micrometers or less.

[0119] The metal layer of the co-laminated 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-laminated sheet may have a thickness of 6 microns.

[0120] The wrapper surrounding the rod of the 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.

[0121] PVOH or silicon may be applied to the paper layer as a surface coating, such as being placed on the outer surface of the paper layer of the wrapper surrounding the rod of the aerosol generating substrate. PVOH or silicon (or polysiloxane) may be placed on the outer surface of the paper layer of the wrapper and may form a layer. PVOH or silicon (or polysiloxane) may be placed on the inner surface of the paper layer of the wrapper. PVOH or silicon (or polysiloxane) may be placed on the inner surface of the paper layer of the aerosol generating article and may form a layer. PVOH or silicon (or polysiloxane) may be placed on both the inner and outer surfaces of the paper layer of the wrapper. PVOH or silicon (or polysiloxane) may be placed on both the inner and outer surfaces of the paper layer of the wrapper and may form a layer.

[0122] A paper wrapper containing PVOH or silicon (or polysiloxane) may have a basis weight of at least 20 gsm, preferably at least 25 gsm, and more preferably at least 30 gsm. A paper wrapper containing PVOH or silicon (or polysiloxane) may have a basis weight of 50 gsm or less, preferably 45 gsm or less, and more preferably 40 gsm or less. A paper wrapper containing PVOH or silicon (or polysiloxane) 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, a paper wrapper containing PVOH or silicon (or polysiloxane) may have a basis weight of 35 gsm.

[0123] A paper wrapper containing PVOH or silicon (or polysiloxane) may have a thickness of at least 25 micrometers, preferably at least 30 micrometers, and more preferably at least 35 micrometers. A paper wrapper containing PVOH or silicon (or polysiloxane) may have a thickness of 50 micrometers or less, preferably 45 micrometers or less, and more preferably 40 micrometers or less. A paper wrapper containing PVOH or silicon (or polysiloxane) may have a thickness of 25 to 50 micrometers, preferably 30 to 45 micrometers, and more preferably 35 to 40 micrometers. In a particularly preferred embodiment, a paper wrapper containing PVOH or silicon (or polysiloxane) may have a thickness of 37 micrometers.

[0124] The wrapper surrounding the rod of the aerosol-generating substrate may comprise a flame-retardant composition containing one or more flame-retardant compounds. The term “flame-retardant compound” is used herein to describe compounds that, when added to or otherwise incorporated into a carrier substrate such as paper or a plastic compound, provide varying degrees of flammability protection to the carrier substrate. In practice, flame-retardant compounds may be activated by the presence of an ignition source and may also be adapted to prevent or slow further progression of ignition through a variety of different physical and chemical mechanisms.

[0125] A flame-retardant composition may typically further contain one or more non-flammable compounds (solvents, excipients, fillers, etc.) that do not actively contribute to providing flammability protection to the carrier substrate, but are used to facilitate the application of the flame-retardant compound(s) on, in, or both the wrapper. Some of the non-flammable compounds (solvents, etc.) in the flame-retardant composition are volatile and may evaporate from the wrapper as it dries after the flame-retardant composition has been applied on, in, or both the wrapping substrate. Thus, although these non-flammable compounds form part of the formulation of the flame-retardant composition, they may no longer be present in the wrapper of the aerosol-generating article, or may only be detectable in trace amounts.

[0126] Numerous suitable flame retardants are known to those skilled in the art. Specifically, several flame retardants and formulations suitable for treating cellulosic materials are known and disclosed and may be found to be used in the manufacture of wrappers for aerosol-generating articles according to the present invention.

[0127] 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 polyphosphate, pyrophosphate, and / or phosphoric acid, and a hydroxide or alkali or alkaline earth metal salt, wherein at least one mono, di, and / or tricarboxylic acid and the hydroxide or salt form a carboxylate and at least one polyphosphate, and the pyrophosphate and / or phosphoric acid and the hydroxide or salt form a phosphate. Preferably, the flame retardant composition further comprises an alkali or alkaline earth metal carbonate. Alternatively, the flame retardant composition comprises at least one C 10 The above fatty acids may include cellulose modified with tall oil fatty acids (TOFA), phosphorylated linseed oil, and phosphorylated downstream corn oil. Preferably, at least one C 10 The above fatty acids are selected from the group consisting of capric acid, myristic acid, palmitic acid, and combinations thereof.

[0128] In a wrapper comprising a flame retardant composition suitable for use in an aerosol-generating article 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 on or in the 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 rods of the aerosol-generating substrate surrounded by the wrapper, preferably at least 20 percent of the outer surface area of ​​the rods of the aerosol-generating substrate surrounded by the wrapper, more preferably over at least 40 percent of the outer surface area of ​​the rods of the aerosol-generating substrate, and even more preferably over at least 60 percent of the outer surface area of ​​the rods of the aerosol-generating substrate. Most preferably, the treated portion of the wrapper extends over at least 80 percent of the outer surface area of ​​the rods of the aerosol-generating substrate. In a particularly preferred embodiment, the treated portion of the wrapper extends over at least 90 percent, or even more preferably 95 percent, of the outer surface area of ​​the rods of the aerosol-generating substrate. It is most preferable that the treated portion of the wrapper extends substantially over the entire outer surface area of ​​the rod of the aerosol generating substrate.

[0129] A wrapper containing a 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. A wrapper containing a 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. A wrapper containing a 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, a wrapper containing a flame-retardant composition may have a basis weight of 33 gsm.

[0130] The wrapper containing the flame retardant composition may have a thickness of at least 25 micrometers, preferably at least 30 micrometers, and 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.

[0131] The aerosol-generating article according to this 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 this disclosure.

[0132] 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 can prevent direct physical contact with the upstream end of the susceptor element. This helps prevent displacement or deformation of the susceptor element during handling or transport of the aerosol-generating article. This consequently 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.

[0133] If the aerosol-generating substrate contains shredded tobacco, such as tobacco cut filler, the upstream section or its components may additionally help prevent the loss of loose tobacco particles from the upstream end of the article. This can be particularly important, for example, when the density of the shredded tobacco is relatively low.

[0134] The upstream section or its upstream element may also provide some degree of additional protection to the aerosol-generating substrate during storage, by covering at least to some extent the upstream end of the aerosol-generating substrate which may otherwise be exposed.

[0135] In the case of an aerosol generating article intended to be inserted into a cavity within an aerosol generating device so that the aerosol generating substrate can be externally heated within the cavity, the upstream section or its upstream element may advantageously facilitate the insertion of the upstream end of the article into the cavity. Including an upstream element may provide additional protection to the ends of the rods of the aerosol generating substrate during insertion of the article into the cavity, thereby minimizing the risk of damage to the substrate.

[0136] The upstream section or its upstream element may also provide an improved appearance to the upstream end of the aerosol-generating article. Furthermore, if desired, the upstream section or its upstream element may be used to provide information about the aerosol-generating article, such as information about the brand, flavor, content, or details of the aerosol generator in which the aerosol-generating article is intended to be used.

[0137] The upstream element may be a porous plug element. Preferably, the upstream element has a porosity of at least 50 percent in the longitudinal direction of the aerosol-generating article. More preferably, the upstream element has a porosity of 50 percent to 90 percent in the longitudinal direction. The porosity of the upstream element in the longitudinal direction is defined by the ratio of the cross-sectional area of ​​the material forming the upstream element to the internal cross-sectional area of ​​the aerosol-generating article at the location of the upstream element.

[0138] The upstream element may be made of a porous material or may have multiple openings. This can be achieved, for example, by laser drilling. Preferably, the multiple openings are uniformly distributed across the cross-section of the upstream element.

[0139] The porosity or permeability of the upstream element may be advantageously designed to provide an aerosol-generating article having a specific overall drawdown resistance (RTD) that does not substantially affect the filtration provided by the other parts of the article.

[0140] The upstream element may be formed from a material that is impermeable to air. In such embodiments, the aerosol generating article may be configured so that air flows into the rods of the aerosol generating substrate through appropriate ventilation means provided within the wrapper.

[0141] In certain preferred embodiments of the present invention, it may be desirable to minimize the RTD of upstream elements. For example, this may apply to articles intended to be inserted into the cavity of an aerosol generator so that the aerosol generating substrate is externally heated, as described herein. In 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 generator rather than the article itself.

[0142] The RTD of the upstream element is preferably less than 30 milliH2O. More preferably, the RTD of the upstream element is less than 20 milliH2O. Even more preferably, the RTD of the upstream element is 10 milliH2O or less. Even more preferably, the RTD of the upstream element is 5 milliH2O or less. Even more preferably, the RTD of the upstream element is 2 milliH2O or less.

[0143] The RTD of the upstream element may be at least 0.1 milliH2O, or at least 0.25 milliH2O, or at least 0.5 milliH2O.

[0144] In some embodiments, the RTD of the upstream element is 0.1 mmH2O to 30 mmH2O, preferably 0.25 mmH2O to 30 mmH2O, and preferably 0.5 mmH2O to 30 mmH2O. In other embodiments, the RTD of the upstream element is 0.1 mmH2O to 20 mmH2O, preferably 0.25 mmH2O to 20 mmH2O, and preferably 0.5 mmH2O to 20 mmH2O. In further embodiments, the RTD of the upstream element is 0.1 mmH2O to 10 mmH2O, preferably 0.25 mmH2O to 10 mmH2O, and more preferably 0.5 mmH2O to 10 mmH2O. In even further embodiments, the RTD of the upstream element is 0.1 mmH2O to 5 mmH2O, preferably 0.25 mmH2O to 5 mmH2O, and more preferably 0.5 mmH2O to 5 mmH2O. In further embodiments, the RTD of the upstream element is 0.1 mmH2O to 2 mmH2O, preferably 0.25 mmH2O to 2 mmH2O, and more preferably 0.5 mmH2O to 2 mmH2O.

[0145] The upstream element preferably has an RTD of less than 2 mmH2O per millimeter, more preferably less than 1.5 mmH2O per millimeter, more preferably less than 1 mmH2O per millimeter, more preferably less than 0.5 mmH2O per millimeter, more preferably less than 0.3 mmH2O per millimeter, and more preferably less than 0.2 mmH2O per millimeter.

[0146] Preferably, the RTD, which is a combination of the upstream section or its upstream element and the rod of the aerosol generating substrate, has less than 15 mmH2O, more preferably less than 12 mmH2O, and more preferably less than 10 mmH2O.

[0147] In certain preferred embodiments, the upstream element is formed of a solid cylindrical plug element having a filled cross-section. Such plug elements may be referred to as “plain” elements. The solid plug element may be porous as described above, but does not have a tubular shape and therefore does not provide a flow channel along its longitudinal axis. The solid plug element preferably has a substantially uniform cross-section.

[0148] 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 to the aerosol-generating substrate as described above, while having minimal effect on the overall draw-to-discard (RTD) and filtration characteristics of the article.

[0149] Preferably, the diameter of the longitudinal cavity of the hollow tubular segment forming the upstream element is at least 3 mm, more preferably at least 3.5 mm, more preferably at least 4 mm, and more preferably at least 4.5 mm. Preferably, the diameter of the longitudinal cavity is maximized to minimize the RTD of the upstream section or its upstream element.

[0150] 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.

[0151] The upstream elements of the upstream section may be made of any material suitable for use in an aerosol generating article. The upstream elements may be made of the same material used for, for example, the downstream filter segment or one of the other components of the aerosol generating article, such as a hollow tubular cooling element. Suitable materials for forming the upstream elements include filter materials, ceramics, polymer materials, cellulose acetate, cardboard, zeolites, or aerosol generating substrates. The upstream elements may include a cellulose acetate plug. The upstream elements may comprise a hollow acetate tube or a cardboard tube.

[0152] The upstream element is preferably made of a heat-resistant material. For example, the upstream element is preferably made of 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 used to heat the aerosol generating substrate.

[0153] The upstream section or its upstream element 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 its upstream element is 5 mm to 8 mm, more preferably 5.25 mm to 7.5 mm, and more preferably 5.5 mm to 7 mm.

[0154] Preferably, the upstream section or upstream element has a length of at least 2 millimeters, more preferably at least 3 millimeters, and more preferably at least 4 millimeters.

[0155] Preferably, the upstream section or upstream element has a length of 2 to 10 mm, more preferably 3 to 8 mm, more preferably 2 to 6 mm, more preferably 3 to 6 mm, more preferably 4 to 8 mm, and more preferably 4 to 6 mm. In a particularly preferred embodiment, the upstream section or upstream element has a length of 5 mm. The length of the upstream section or upstream element can be advantageously varied to provide the desired overall length of the aerosol-generating article. For example, if it is desirable to reduce the length of one of the other components of the aerosol-generating article, the length of the upstream section or upstream element may be increased to maintain the same overall length of the article.

[0156] In addition, for articles intended to be externally heated, the length of the upstream section or its upstream element can be used to control the position of the aerosol-generating article within the cavity of the aerosol generator. This is advantageous because it ensures that the position of the aerosol-generating substrate within the cavity can be optimized for heating, as well as the position of any ventilation.

[0157] The upstream section is preferably surrounded by a wrapper such as a plug wrap. The wrapper surrounding the upstream section is preferably a rigid 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. This provides structural rigidity to the upstream section.

[0158] The upstream section is preferably connected to the rods of the aerosol generating substrate and, optionally, to at least a portion of the downstream section by an outer wrapper as described herein.

[0159] As described above, the aerosol generating article according to the present invention comprises a downstream section located downstream of the rod of the aerosol generating substrate. Preferably, the downstream section is located immediately downstream of the rod of the aerosol generating substrate. Preferably, the downstream section of the aerosol generating article extends between the rod of the 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 in this disclosure.

[0160] 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.

[0161] 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.

[0162] For example, the length of the downstream section may be 40 to 75 millimeters, or 45 to 75 millimeters, or 48 to 75 millimeters, or 50 to 75 millimeters. In other embodiments, the length of the downstream section may be 40 to 70 millimeters, or 45 to 70 millimeters, or 48 to 70 millimeters, or 50 to 70 millimeters. In other embodiments, the length of the downstream section may be 40 to 65 millimeters, or 45 to 65 millimeters, or 48 to 65 millimeters, or 50 to 65 millimeters.

[0163] By providing a relatively long downstream section, it is ensured that an appropriate length of the aerosol-generating article protrudes from the aerosol generator when the article is received into the aerosol generator. This appropriate protrusion length facilitates the ease of inserting and removing the article from the device, which also ensures that the upstream portion of the article is properly inserted into the device, reducing the risk of damage, especially during insertion.

[0164] The ratio between the length of the downstream section and the total length of the aerosol-generating article may be less than 0.85. Preferably, the ratio between the length of the downstream section and the total 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 total 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 total length of the aerosol-generating article may be less than 0.70.

[0165] The ratio between the length of the downstream section and the total length of the aerosol-generating article may be at least 0.50. Preferably, the ratio between the length of the downstream section and the total 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 total 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 total length of the aerosol-generating article may be at least 0.65.

[0166] In some embodiments, the ratio between the length of the downstream section and the total 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 total 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 total 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 further embodiments, the ratio between the length of the downstream section and the total length of the aerosol-generating article is 0.50 to 0.70, preferably 0.55 to 0.70, more preferably 0.60 to 0.70, and even more preferably 0.65 to 0.70.

[0167] 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.

[0168] The ratio of the length of the downstream section to the length of the upstream section may be at least 4. Preferably, the ratio may be at least 5. More preferably, the ratio may be at least 6. Even more preferably, the ratio may be at least 7.

[0169] In some embodiments, the ratio of the length of the downstream section to 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 of the length of the downstream section to 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 of the length of the downstream section to 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 even further embodiments, the ratio of the length of the downstream section to 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.

[0170] The ratio between the length of the downstream section and the length of the rod of the aerosol generating substrate is preferably at least 1.0. More preferably, the ratio between the length of the downstream section and the length of the rod of the aerosol generating substrate is at least 1.25. More preferably, the ratio between the length of the downstream section and the length of the rod of the aerosol generating substrate is at least 1.5. More preferably, the ratio between the length of the downstream section and the length of the rod of the aerosol generating substrate is at least 1.75.

[0171] The ratio of the length of the downstream section to the length of the rod of the aerosol generating substrate is preferably less than 3.5. Preferably, the ratio of the length of the downstream section to the length of the rod of the aerosol generating substrate is less than 3.25. More preferably, the ratio of the length of the downstream section to the length of the rod of the aerosol generating substrate is less than 3.0. Even more preferably, the ratio of the length of the downstream section to the length of the rod of the aerosol generating substrate is less than 2.75.

[0172] 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 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.

[0173] The downstream section of the aerosol generating article according to the present invention preferably comprises a hollow tubular cooling element provided downstream of the rod of the aerosol generating substrate. The hollow tubular cooling element may advantageously provide an aerosol cooling element for the aerosol generating article.

[0174] A 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 may comprise two or more hollow tubular elements, as described below.

[0175] As used throughout this disclosure, the term “hollow tubular element” generally means an elongated element that defines a lumen or airflow passage along its longitudinal axis. In particular, the term “tubular” is used below with respect to a tubular element having a substantially cylindrical cross-section and defining at least one airflow conduit that establishes uninterrupted fluid communication between the upstream and downstream ends of the tubular element. However, naturally, alternative shapes of tubular elements (e.g., alternative cross-sectional shapes) may be possible. A hollow tubular cooling element may be an individual, distinct element of an aerosol-generating article having a defined length and thickness.

[0176] The internal 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 internal volume defined by the hollow tubular cooling element may be at least 300 cubic millimeters. The internal volume defined by the hollow tubular cooling element may be at least 700 cubic millimeters.

[0177] The internal volume defined by the hollow tubular cooling element may be 1200 cubic millimeters or less. Preferably, the internal volume defined by the hollow tubular cooling element may be 1000 cubic millimeters or less. The internal volume defined by the hollow tubular cooling element may be 900 cubic millimeters or less.

[0178] The internal volume defined by the hollow tubular cooling element may be 100 to 1200 cubic millimeters. Preferably, the internal volume defined by the hollow tubular cooling element may be 300 to 1000 cubic millimeters. The internal volume defined by the hollow tubular cooling element may be 700 to 900 cubic millimeters.

[0179] In the context of the present invention, the hollow tubular cooling element provides an unrestricted flow channel. This means that the hollow tubular cooling element provides a negligible level of drawdown resistance (RTD). The term “negligible level of RTD” is used to describe an RTD of less than 1 mmH2O per 10 mm of length of the hollow tubular cooling element, preferably less than 0.4 mmH2O per 10 mm of length of the hollow tubular cooling element, and more preferably less than 0.1 mmH2O per 10 mm of length of the hollow tubular cooling element.

[0180] The RTD of the hollow tubular cooling element is preferably 10 mmH2O or less. More preferably, the RTD of the hollow tubular cooling element is 5 mmH2O or less. Even more preferably, the RTD of the hollow tubular cooling element is 2.5 mmH2O or less. Even more preferably, the RTD of the hollow tubular cooling element is 2 mmH2O or less. Even more preferably, the RTD of the hollow tubular cooling element is 1 mmH2O or less.

[0181] The RTD of a hollow tubular cooling element may contain at least 0 mmH2O, or at least 0.25 mmH2O, or at least 0.5 mmH2O, or at least 1 mmH2O.

[0182] In some embodiments, the RTD of the hollow tubular cooling element is 0 mmH2O to 10 mmH2O, preferably 0.25 mmH2O to 10 mmH2O, and more preferably 0.5 mmH2O to 10 mmH2O. In other embodiments, the RTD of the hollow tubular cooling element is 0 mmH2O to 5 mmH2O, preferably 0.25 mmH2O to 5 mmH2O, and more preferably 0.5 mmH2O to 5 mmH2O. In yet another embodiment, the RTD of the hollow tubular cooling element is 1 mmH2O to 5 mmH2O. In a further embodiment, the RTD of the hollow tubular cooling element is 0 mmH2O to 2.5 mmH2O, preferably 0.25 mmH2O to 2.5 mmH2O, and more preferably 0.5 mmH2O to 2.5 mmH2O. In further embodiments, the RTD of the hollow tubular cooling element is 0 mmH2O to 2 mmH2O, preferably 0.25 mmH2O to 2 mmH2O, and more preferably 0.5 mmH2O to 2 mmH2O. In one particularly preferred embodiment, the RTD of the hollow tubular cooling element is 0 mmH2O.

[0183] In the aerosol-generating article according to the present invention, the overall RTD of the article depends essentially on the RTD of the rods and, optionally, on the RTD of the downstream and / or upstream elements. This is because the hollow tubular cooling elements are substantially empty and therefore contribute only substantially little to the overall RTD of the aerosol-generating article.

[0184] Therefore, the flow channel should not contain any components that would obstruct the airflow in the longitudinal direction. The flow channel is preferably substantially empty, and particularly preferably empty.

[0185] As described in more detail in this disclosure, the aerosol generating article may have a ventilation zone located along the downstream section. In some embodiments, the aerosol generating article may have a ventilation zone located along a hollow tubular cooling element. Such, or any, ventilation zones may extend through the peripheral wall of the hollow tubular cooling element. Thus, fluid communication is established between the flow channel internally defined by the hollow tubular cooling element and the external environment. The ventilation zones are described further in this disclosure.

[0186] The length of the hollow tubular cooling element is preferably at least 20 millimeters. More preferably, the length of the hollow tubular cooling element is at least 30 millimeters. The length of the hollow tubular cooling element may be at least 40 millimeters. More preferably, the length of the hollow tubular cooling element is at least 45 millimeters.

[0187] The length of the hollow tubular cooling element is preferably less than 60 millimeters. The length of the hollow tubular cooling element is more preferably less than 55 millimeters. The length of the hollow tubular cooling element is more preferably less than 50 millimeters.

[0188] For example, the length of the hollow tubular cooling element may be 20 to 60 mm, or 30 to 60 mm, or 40 to 60 mm, or 45 to 60 mm. In other embodiments, the length of the hollow tubular cooling element may be 20 to 55 mm, or 30 to 55 mm, or 40 to 55 mm, or 45 to 55 mm. In other embodiments, the length of the hollow tubular cooling element may be 20 to 50 mm, or 30 to 50 mm, or 40 to 50 mm, or 45 to 50 mm.

[0189] A 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 of the aerosol-generating substrate (preferably immediately downstream) enhances the 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.

[0190] The ratio between the length of the hollow tubular cooling element and the length of the rod of the aerosol generating substrate is preferably at least 1.0. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the rod of the aerosol generating substrate is at least 1.25. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the rod of the aerosol generating substrate is at least 1.5. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the rod of the aerosol generating substrate is at least 1.75.

[0191] The ratio between the length of the hollow tubular cooling element and the length of the rod of the aerosol generating substrate is preferably less than 3.5. Preferably, the ratio between the length of the hollow tubular cooling element and the length of the rod of the aerosol generating substrate is preferably less than 3.25. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the rod of the aerosol generating substrate is less than 3.0. Even more preferably, the ratio between the length of the hollow tubular cooling element and the length of the rod of the aerosol generating substrate is less than 2.75.

[0192] 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 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 2.75, preferably 1.25 to 2.75, more preferably 1.50 to 2.75, and even more preferably 1.75 to 2.75.

[0193] 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.

[0194] The ratio of the length of the hollow tubular cooling element to the length of the downstream section may be at least 0.35. Preferably, the ratio of the length of the hollow tubular cooling element to the length of the downstream section may be at least 0.45. More preferably, the ratio of the length of the hollow tubular cooling element to the length of the downstream section may be at least 0.50. Even more preferably, the ratio of the length of the hollow tubular cooling element to the length of the downstream section may be at least 0.60.

[0195] In some embodiments, the ratio of the length of the hollow tubular cooling element to 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 of the length of the hollow tubular cooling element to 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 of the length of the hollow tubular cooling element to 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. As an example, the ratio of the length of the hollow tubular cooling element to the length of the downstream section may preferably be 0.75.

[0196] The ratio between the length of the hollow tubular cooling element and the total 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 total 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 total 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 total length of the aerosol generating article may be 0.65 or less.

[0197] The ratio between the length of the hollow tubular cooling element and the total 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 total 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 total 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 total length of the aerosol generating article may be at least 0.6.

[0198] In some embodiments, the ratio between the length of the hollow tubular cooling element and the total 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 total 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 total 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 further embodiments, the ratio between the length of the hollow tubular cooling element and the total length of the aerosol-generating article is 0.40 to 0.65, preferably 0.45 to 0.65, more preferably 0.50 to 0.65, and even more preferably 0.60 to 0.65.

[0199] Providing a downstream section or hollow tubular cooling element having the ratios listed above maximizes the aerosol cooling and formation advantages of having a relatively long hollow tubular cooling element, while providing a sufficient amount of filtration for aerosol-generating articles configured to be heated rather than burned. Furthermore, 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.

[0200] 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).

[0201] The wall thickness of the hollow tubular cooling element may be 2 millimeters or less, preferably 1.5 millimeters or less, and 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.

[0202] The wall thickness of the hollow tubular cooling element may be 100 micrometers to 2 millimeters, preferably 150 micrometers to 1.5 millimeters, and more preferably 200 micrometers to 1.25 millimeters.

[0203] The wall thickness of the hollow tubular cooling element may preferably be 250 micrometers (0.25 millimeters).

[0204] At the same time, keeping the thickness of the peripheral walls of the hollow tubular cooling element relatively low ensures that the overall internal volume of the hollow tubular cooling element (which is made available for the aerosol to begin the nucleation process as soon as the aerosol components leave the rod of the aerosol generating substrate) and the cross-sectional surface area of ​​the hollow tubular cooling element are effectively maximized, while simultaneously ensuring that the hollow tubular cooling element has the structural strength necessary to provide some support to the rod of the aerosol generating substrate as well as to prevent the collapse of the aerosol generating article, and that the RTD of the hollow tubular cooling element is minimized. A larger value of the cross-sectional surface area of ​​the cavity of the hollow tubular cooling element is understood to be associated with a reduced rate of aerosol flow along the aerosol generating article, which is expected to be favorable for aerosol nucleation. Furthermore, by utilizing a hollow tubular cooling element with a relatively small thickness, it appears that the diffusion of the venting air can be substantially prevented before it comes into contact with and mixes with the aerosol flow, which is also understood to be more favorable to the nucleation phenomenon. In fact, by providing more controllably localized cooling of the volatile seed flow, it is possible to enhance the cooling effect on the formation of new aerosol particles.

[0205] The hollow tubular cooling element preferably has an outer diameter that is approximately equal to the outer diameter of the rod of the aerosol generating substrate and the outer diameter of the aerosol generating article.

[0206] The hollow tubular cooling element may have an outer diameter of 5 to 10 mm, for example, 5.5 to 9 mm, or 6 to 8 mm. In a preferred embodiment, the hollow tubular cooling element has an outer diameter of less than 7 mm.

[0207] The hollow tubular cooling element may have an inner diameter. Preferably, the hollow tubular cooling element may have a constant inner diameter along its length. However, the inner diameter of the hollow tubular cooling element may vary along its length.

[0208] 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.

[0209] By providing a hollow tubular cooling element having the inner diameter as described above, it is advantageous that sufficient rigidity and strength can be provided to the hollow tubular cooling element.

[0210] The hollow tubular cooling element may have an inner diameter of 10 mm or less. For example, the hollow tubular cooling element may have an inner diameter of 9 mm or less, 8 mm or less, or 7 mm or less.

[0211] Providing a hollow tubular cooling element with the inner diameter described above has the advantage of potentially reducing the withdrawal resistance of the hollow tubular cooling element.

[0212] The hollow tubular cooling element may have an inner diameter of 2 mm to 10 mm, 3 mm to 9 mm, 4 mm to 8 mm, or 5 mm to 7 mm.

[0213] The ratio between the inner diameter and outer diameter of the hollow tubular cooling element may be at least 0.8. For example, the ratio between the inner diameter and outer diameter of the hollow tubular cooling element may be at least 0.85, at least 0.9, or at least 0.95.

[0214] The ratio between the inner diameter and outer diameter of a hollow tubular cooling element may be 0.99 or less. For example, the ratio between the inner diameter and outer diameter of a hollow tubular cooling element may be 0.98 or less.

[0215] 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.

[0216] Providing a relatively large inner diameter can be advantageous in that it reduces the withdrawal resistance of the hollow tubular cooling element and enhances the cooling and nucleation of aerosol particles.

[0217] 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.

[0218] The hollow tubular cooling element may contain a paper-based material. The hollow tubular cooling element may contain at least one layer of paper. The paper may be very rigid. The paper may be crimped paper such as crimped heat-resistant paper or crimped sulfuric acid paper.

[0219] Preferably, the hollow tubular cooling element may include 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 inserting the article into the aerosol generator and being rigid enough to provide proper engagement of the article with the inside of the device. Thus, the cardboard tube may provide good resistance to deformation or compression during use.

[0220] 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.

[0221] The hollow tubular cooling element may contain polymer materials. For example, the hollow tubular cooling element may contain a polymer film. The polymer film may contain a cellulose film. The hollow tubular cooling element may contain low-density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers. The hollow tube may contain cellulose acetate tow.

[0222] If the hollow tubular cooling element contains cellulose acetate tow, the cellulose acetate tow may have 2 to 4 denier per filament and a total denier of 25 to 40.

[0223] In some embodiments, the aerosol-generating article according to the present invention may include a ventilation zone located along the downstream section. More specifically, 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.

[0224] Thus, a ventilated cavity is provided downstream of the rod of the aerosol-generating substrate. This offers several potential technical advantages.

[0225] Firstly, the inventors found that a single such ventilated, hollow, tubular cooling element provides particularly efficient cooling of the aerosol. Therefore, satisfactory cooling of the aerosol can be achieved even by a relatively short downstream section. This is particularly desirable because it enables the provision of aerosol-generating articles in which the aerosol-generating substrate (and especially those containing tobacco) is heated rather than burned, combining satisfactory aerosol delivery with efficient cooling of the aerosol to a temperature desirable for the consumer.

[0226] Secondly, the inventors surprisingly found that this rapid cooling of volatile species released upon heating of the aerosol-generating substrate promotes and enhances the nucleation of aerosol particles. This effect is particularly noticeable when the ventilation zone is positioned at a precisely defined location along the length of the hollow tubular cooling element relative to the other components of the aerosol-generating article, as will be described in more detail below. In fact, the inventors 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.

[0227] 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 part of the aerosol-generating article” refers to a measured distance in the longitudinal direction, i.e., in the direction extending along or parallel to the cylindrical axis of the aerosol-generating article.

[0228] 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.

[0229] The distance between the ventilation zone and the upstream end of the upstream element may 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.

[0230] In some embodiments, the distance between the ventilation zone and the upstream end of the upstream element is 25 to 34 millimeters, preferably 26 to 34 millimeters, and more preferably 27 to 34 millimeters.

[0231] In other embodiments, the distance between the ventilation zone and the upstream end of the upstream element is 25 to 33 millimeters, preferably 26 to 33 millimeters, and more preferably 27 to 33 millimeters.

[0232] In further embodiments, the distance between the ventilation zone and the upstream end of the upstream element is 25 to 31 millimeters, preferably 26 to 31 millimeters, and more preferably 27 to 31 millimeters.

[0233] In some particularly preferred embodiments, the distance between the ventilation zone and the upstream end of the upstream element is 28 to 30 millimeters.

[0234] Aerosol generating articles having a ventilation zone positioned along a hollow tubular cooling element at a distance from the upstream end of the upstream element within the above range have been found to offer multiple benefits.

[0235] Firstly, these articles have been observed to provide consumers with particularly satisfactory aerosol delivery, especially when the aerosol-generating substrate contains tobacco.

[0236] While we do not wish to be bound by theory, it is understood that the intense cooling caused by ambient air drawn into the cavity of the hollow tubular cooling element in the ventilation zone accelerates the condensation of droplets of aerosol-forming material (e.g., glycerin) released from the aerosol-generating substrate upon heating. Subsequently, volatile nicotine and organic acids similarly released from the tobacco substrate accumulate on the newly formed droplets of aerosol-forming material and then bind to nicotine salts. Thus, the overall ratio of the aerosol particle phase to the aerosol gas phase can be enhanced compared to existing aerosol-generating articles.

[0237] By positioning the ventilation zone at a distance from the upstream end of the upstream element as described above, the flight time of volatile nicotine particles is advantageously reduced 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 the aerosol flow has sufficient time and space for a considerable amount of nicotine accumulation and nicotine salt formation to occur before it reaches the consumer's mouth.

[0238] The ventilation zone may typically include a plurality of perforations running through the circumferential wall of a 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 8 to 30 perforations.

[0239] The aerosol-generating article according to the present invention may have a breathability level of at least 2 percent.

[0240] The term "ventilation level" is used throughout this specification to mean the volume ratio between the airflow entering the aerosol-generating article through the ventilation zone (ventilation airflow) and the sum of the aerosol airflow and the ventilation airflow. A higher ventilation level results in greater dilution of the aerosol flow delivered to the consumer. The aerosol-generating article preferably has a ventilation level of at least 5 percent, more preferably at least 10 percent, even more preferably at least 12 percent or at least 15 percent.

[0241] The aerosol-generating article according to the present invention may have a ventilation level of up to 90 percent. Preferably, the aerosol-generating article according to the present invention has a ventilation 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.

[0242] Therefore, the aerosol-generating article according to the present invention may have an air permeability level of 2 percent to 90 percent, preferably 5 percent to 90 percent, more preferably 10 percent to 90 percent, and even more preferably 15 percent to 90 percent. The aerosol-generating article according to the present invention may have an air permeability level of 2 percent to 80 percent, preferably 5 percent to 80 percent, more preferably 10 percent to 80 percent, and even more preferably 15 percent to 80 percent. The aerosol-generating article according to the present invention may have an air permeability level of 2 percent to 70 percent, preferably 5 percent to 70 percent, more preferably 10 percent to 70 percent, and even more preferably 15 percent to 70 percent. The aerosol-generating article according to the present invention may have an air permeability level of 2 percent to 60 percent, preferably 5 percent to 60 percent, more preferably 10 percent to 60 percent, and even more preferably 15 percent to 60 percent. The aerosol-generating article according to the present invention may have an air permeability level of 2 percent to 50 percent, preferably 5 percent to 50 percent, more preferably 10 percent to 50 percent, and even more preferably 15 percent to 50 percent. The aerosol-generating article preferably has an air permeability 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.

[0243] In some embodiments, the aerosol-generating article has an air permeability level of 10 to 30 percent, preferably 12 to 30 percent, more preferably 15 to 30 percent. In other embodiments, the aerosol-generating article has an air permeability level of 10 to 25 percent, preferably 12 to 25 percent, more preferably 15 to 25 percent. In further embodiments, the aerosol-generating article has an air permeability level of 10 to 20 percent, preferably 12 to 20 percent, more preferably 15 to 20 percent. In a particularly preferred embodiment, the aerosol-generating article has an air permeability level of 10 to 18 percent, preferably 12 to 18 percent, more preferably 15 to 18 percent.

[0244] While not wishing to be constrained by theory, the inventors found that the temperature reduction resulting from introducing colder outside air into a hollow tubular cooling element through a ventilation zone can have a favorable effect on the nucleation and growth of aerosol particles.

[0245] The formation of aerosols from gaseous mixtures containing various chemical species depends on the delicate interactions between nucleation, evaporation, condensation, and even fusion, which explain changes in vapor concentration, temperature, and velocity fields. So-called classical nucleation theory is based on the assumption that some molecules in the gas phase are large enough to remain coherent for a long time with a sufficient probability (e.g., a 50 / 50 probability). These molecules represent a kind of critical threshold molecular cluster in transient molecular aggregates, meaning that smaller molecular clusters generally decompose into the gas phase somewhat more readily, while larger clusters generally grow more readily. These critical clusters are identified as the main nucleation cores from which droplets are expected to grow due to the condensation of molecules from the vapor. The newly nucleated, untreated droplet is assumed to emerge with a certain intrinsic diameter and then grow by several orders of magnitude. This can be facilitated and enhanced by the rapid cooling of the surrounding vapor, which induces condensation. In this regard, it is helpful to keep in mind that evaporation and condensation are two aspects of the same mechanism: the transfer of mass between liquid and gas. Evaporation involves net mass transfer from the liquid droplet phase to the gas phase, while condensation is net mass transfer from the gas phase to the liquid droplet phase. Due to evaporation (or condensation), the liquid droplet shrinks (or grows), but the number of droplets does not change.

[0246] In this scenario (and if the scenario is further complicated by fusion phenomena), the temperature and rate of cooling may play a crucial role in determining how the system responds. Generally, because the nucleation process is typically nonlinear, different cooling rates may lead to significantly different temperature behavior with respect to liquid phase (droplet) formation. While we do not wish to be bound by theory, we assume that cooling can result in a rapid increase in the number of droplet condensations, followed by a short, strong increase in this growth (nucleation burst). This nucleation burst is likely to be more pronounced at lower temperatures. Furthermore, faster cooling rates may favor the early initiation of nucleation. In contrast, a decrease in the cooling rate is likely to have a favorable effect on the final size that the aerosol droplets eventually reach.

[0247] Therefore, rapid cooling induced by introducing outside air into a hollow tubular cooling element through a ventilation zone can be used to favorably nucleate and grow aerosol droplets. However, at the same time, introducing outside air into a hollow tubular cooling element has the direct disadvantage of diluting the aerosol flow delivered to the consumer.

[0248] The inventors were surprised to find that the desirable effect of enhanced nucleation, facilitated by rapid cooling induced by the introduction of aeration air into the article, significantly counteracts the undesirable effect of dilution. Thus, satisfactory values ​​of aerosol delivery can be consistently achieved using the aerosol-generating article according to the present invention.

[0249] The inventors also surprisingly found that the dilution effect on aerosols, which can be evaluated by measurement, specifically the effect on the delivery of aerosol-forming substances (e.g., glycerol) contained in the aerosol-generating substrate, is advantageously minimized when the permeability level is within the aforementioned range.

[0250] Specifically, it was found that permeability levels of 10 to 20 percent, and more preferably 12 to 18 percent, led to particularly satisfactory values ​​of glycerol delivery.

[0251] Since the vented, hollow tubular cooling element substantially does not contribute to the overall RTD of the aerosol-generating article, in the 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 density of the segments of the filtration material forming part of the downstream section (e.g., downstream filter segments), and optionally the length and density of the segments of the filtration material provided upstream of the aerosol-generating substrate. Thus, aerosol-generating articles having a predetermined RTD can be manufactured consistently and with high precision, thereby providing consumers with a satisfactory level of RTD, even in the presence of ventilation.

[0252] 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.

[0253] The distance between the ventilation zone and the downstream end of the rod of the aerosol generating substrate is preferably less than 17 millimeters. More preferably, the distance between the ventilation zone and the downstream end of the rod of the aerosol generating substrate is less than 16 millimeters. Even more preferably, the distance between the ventilation zone and the downstream end of the rod of the aerosol generating substrate is less than 16 millimeters. In a particularly preferred embodiment, the distance between the ventilation zone and the downstream end of the rod of the aerosol generating substrate is less than 15 millimeters.

[0254] 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. As an 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.

[0255] Positioning the ventilation zone within the aforementioned range from the downstream end of the aerosol generating substrate rod has the advantage that, during use, when the aerosol generating article is inserted into the heating device, the ventilation zone is located just outside the heating device, generally ensuring a reduced risk of the ventilation zone being accidentally blocked by the user's lips or hands. Additionally, it has been found that positioning the ventilation zone slightly within the aforementioned range from the downstream end of the aerosol generating substrate rod may advantageously enhance nucleation and aerosol formation and delivery.

[0256] 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.

[0257] The distance between the ventilation zone and the downstream end of the hollow tubular cooling element is preferably 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.

[0258] In some embodiments, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is 3 to 14 millimeters, preferably 5 to 14 millimeters, and more preferably 7 to 14 millimeters. In further embodiments, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is 3 to 12 millimeters, preferably 5 to 12 millimeters, and more preferably 7 to 12 millimeters. In other embodiments, the distance between the ventilation zone and the downstream end of the hollow tubular cooling element is 3 to 10 millimeters, preferably 5 to 10 millimeters, and more preferably 7 to 10 millimeters.

[0259] Positioning the ventilation zone within the aforementioned range from the downstream end of the hollow tubular cooling element has the advantage that, when the aerosol-generating article is inserted into the heating device during use, the ventilation zone is located just outside the heating device, generally ensuring a reduced risk of the ventilation zone being accidentally blocked by the user's lips or hands. Additionally, it has been found that positioning the ventilation zone within the aforementioned range from the downstream end of the hollow tubular cooling element can advantageously lead to relatively more uniform aerosol formation and delivery.

[0260] 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.

[0261] The distance between the ventilation zone and the downstream end of the aerosol-generating article is preferably 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.

[0262] In some embodiments, the distance between the ventilation zone and the downstream end of the aerosol-generating article is 10 to 21 millimeters, preferably 12 to 21 millimeters, and more preferably 15 to 21 millimeters. In further embodiments, the distance between the ventilation zone and the downstream end of the aerosol-generating article is 10 to 19 millimeters, preferably 12 to 19 millimeters, and more preferably 15 to 19 millimeters. In other embodiments, the distance between the ventilation zone and the downstream end of the aerosol-generating article is 10 to 17 millimeters, preferably 12 to 17 millimeters, and more preferably 15 to 17 millimeters.

[0263] Positioning the ventilation zone within the aforementioned range from the downstream end of the aerosol-generating article has the advantage that, during 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 for the consumer to comfortably hold the article with their lips, and this generally ensures that the risk of the ventilation zone being accidentally blocked by the user's lips or hands is reduced. At the same time, evidence suggests that if the length of the portion of the aerosol-generating article extending outside the heating device is longer, it may be easier to bend the aerosol-generating article in an inadequate and undesirable manner, which may impair aerosol delivery or the intended use of the aerosol-generating article in general.

[0264] 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.

[0265] The downstream filter segment may be located downstream of the hollow tubular cooling element, as described above. The downstream filter segment may extend between the hollow tubular cooling element and the downstream end of the aerosol generating article.

[0266] The downstream filter segment is preferably a solid plug, which may also be described as a "plain" plug and is non-tubular. Therefore, the filter segment is preferably substantially uniform in cross-sectional area.

[0267] The downstream filter segment is preferably formed of a fibrous filter material. The fibrous filter material may be for filtering aerosols generated from the aerosol generating substrate. Suitable fibrous filter materials will be known to those skilled in the art. Particularly preferably, at least one downstream filter segment includes a cellulose acetate filter segment formed from cellulose acetate tow.

[0268] In certain preferred embodiments, the downstream section includes a single downstream filter segment. In alternative embodiments, the downstream section includes two or more downstream filter segments aligned axially, with their ends touching each other.

[0269] The downstream filter segment may optionally contain flavoring agents, which can be provided in any preferred form. For example, the downstream filter segment may comprise one or more capsules, beads, or granules of the flavoring agent, or threads or filaments filled with one or more flavoring agents.

[0270] The downstream filter segment preferably has a low particle filtration efficiency.

[0271] The downstream filter segment is preferably surrounded by a plug wrap. The downstream filter segment is preferably not permeable to air so that air does not enter the aerosol-generating article along the downstream filter segment.

[0272] The downstream filter segment is preferably connected by a chipping wrapper to one or more adjacent upstream components of the aerosol-generating article.

[0273] 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.

[0274] The outer diameter of the downstream filter segment may be 5 to 10 millimeters. The diameter of the downstream filter segment may be 5.5 to 9 millimeters. The diameter of the downstream filter segment may be 6 to 8 millimeters. In a preferred embodiment, the diameter of the downstream filter segment is less than 7 millimeters.

[0275] Unless otherwise specified, the draw resistance (RTD) of a component or aerosol-generating article shall be 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 may also refer to “resistance to draw.” These terms generally refer to the fact that the measurement in accordance with ISO 6565-2015 is successfully performed under a test of a volumetric flow rate of 17.5 ml per second at the output or downstream end of the measured component, at a temperature of 22 degrees Celsius, a pressure of 101 kPa (approximately 760 Torr), and a relative humidity of 60%. The conditions for smoking and the specifications of the smoking machine are presented in ISO standard 3308 (ISO 3308:2000). The atmosphere for adjustment and testing is presented in ISO standard 3402 (ISO 3402:1999).

[0276] The draw-out resistance (RTD) of the downstream section may be at least 0 milliH2O. The RTD of the downstream section may be at least 3 milliH2O. The RTD of the downstream section may be at least 6 milliH2O.

[0277] The RTD of the downstream section may be 12 mmH2O or less. The RTD of the downstream section may be 11 mmH2O or less. The RTD of the downstream section may be 10 mmH2O or less.

[0278] The draw resistance of the downstream section may be 0 mmH2O or more and less than 12 mmH2O. Preferably, the draw resistance of the downstream section may be 3 mmH2O or more and less than 12 mmH2O. The draw resistance of the downstream section may be 0 mmH2O or more and less than 11 mmH2O. Even more preferably, the draw resistance of the downstream section may be 3 mmH2O or more and less than 11 mmH2O. Even more preferably, the draw resistance of the downstream section may be 6 mmH2O or more and less than 10 mmH2O. Preferably, the draw resistance of the downstream section may be 8 mmH2O.

[0279] The draw-out resistance (RTD) characteristics of the downstream section may be entirely or largely due to the RTD characteristics of the downstream filter segment of the downstream section. In other words, the RTD of the downstream filter segment of the downstream section may completely define the RTD of the downstream section.

[0280] The draw-out resistance (RTD) of the downstream filter segment may be at least 0 mmH2O. The RTD of the downstream filter segment may be at least 3 mmH2. The RTD of the downstream filter segment may be at least 6 mmH2O.

[0281] The RTD of the downstream filter segment may be 12 mmH2O or less. The RTD of the downstream filter segment may be 11 mmH2O or less. The RTD of the downstream filter segment may be 10 mmH2O or less.

[0282] The withdrawal resistance of the downstream filter segment may be 0 millimeter H2O or more and less than 12 millimeters H2O. Preferably, the withdrawal resistance of the downstream filter segment may be 3 millimeters H2O or more and less than 12 millimeters H2O. The withdrawal resistance of the downstream filter segment may be 0 millimeter H2O or more and less than 11 millimeters H2O. Even more preferably, the withdrawal resistance of the downstream filter segment may be 3 millimeters H2O or more and less than 11 millimeters H2O. Even more preferably, the withdrawal resistance of the downstream filter segment may be 6 millimeters H2O or more and less than 10 millimeters H2O. Preferably, the withdrawal resistance of the downstream filter segment may be 8 millimeters H2O.

[0283] As described above, the downstream filter segment can be formed of a fibrous material. The downstream filter segment may be formed of a porous material. The downstream filter segment may be formed of a biodegradable material. The downstream filter segment may be formed of a cellulose material such as cellulose acetate. For example, the downstream filter segment may be formed from a bundle of cellulose acetate fibers having 10 to 15 denier per filament. For example, the downstream filter segment is formed from a relatively low density cellulose acetate tow, such as cellulose acetate tow containing fibers of 12 denier per filament.

[0284] The downstream filter segment can be formed of a polylactic acid-based material. The downstream filter segment can be formed of a biodegradable plastic material, preferably a starch-based biodegradable plastic material. The downstream filter segment can be produced by injection molding or extrusion molding. The biodegradable plastic-based material is advantageous because it can provide a downstream filter segment structure that is easy and inexpensive to manufacture due to a specific complex cross-sectional profile with a plurality of relatively large air flow channels extending through the downstream filter segment material that provides suitable RTD characteristics.

[0285] The downstream filter segment can be formed from a sheet of suitable material that has been subjected to processes such as winding, pleating, gathering, weaving, or folding to define a plurality of channels extending in the longitudinal direction. Such sheets of suitable material can be formed of paper, cardboard, polymers such as polylactic acid, or any other cellulosic, paper-based or bioplastic-based material. The cross-sectional profile of such a downstream filter segment can exhibit randomly oriented channels.

[0286] 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 tubes extending in the longitudinal direction. The tubes extending in the longitudinal direction can be formed of polylactic acid. The downstream filter segment may be formed by extrusion, molding, lamination, injection or shredding of suitable materials. Thus, it is preferable that there is a low pressure drop (or RTD) from the upstream end to the downstream end of the downstream filter segment.

[0287] 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 5 millimeters to 25 millimeters, or 10 millimeters to 25 millimeters, or 5 millimeters to 20 millimeters, or 10 millimeters to 20 millimeters.

[0288] 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.

[0289] 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.

[0290] In some embodiments, the ratio of the length of the downstream filter segment to 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 of the length of the downstream filter segment to 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 of the length of the downstream filter segment to 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. For example, the ratio of the length of the downstream filter segment to the length of the downstream section may preferably be 0.20 to 0.25, and more preferably 0.25.

[0291] The ratio between the length of the downstream filter segment and the total 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 total 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 total 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 total length of the aerosol generating article may be 0.20 or less.

[0292] The ratio between the length of the downstream filter segment and the total 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 total 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 total 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 total length of the aerosol generating article may be at least 0.15.

[0293] In some embodiments, the ratio between the length of the downstream filter segment and the total 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 total 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 total 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 total 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 total length of the aerosol-generating article may be 0.16.

[0294] In embodiments where 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 equivalent 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.

[0295] The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be 8.5 or less. The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be 6 or less. The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be 4 or less.

[0296] 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.

[0297] In certain preferred embodiments, the downstream section may include a ventilation zone located downstream of the downstream filter segment. In one embodiment, the ventilation zone located downstream of the downstream filter segment may be provided instead of a ventilation zone located along a hollow tubular cooling element. In another embodiment, the ventilation zone located downstream of the downstream filter segment may be provided in addition to a ventilation zone provided at a location on the hollow tubular cooling element.

[0298] The ventilation zone downstream of the filter segment may include multiple 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 8 to 30 perforations.

[0299] The downstream section may further comprise one or more additional hollow tubular elements.

[0300] In certain embodiments, the downstream section may include a hollow tubular support element upstream of the hollow tubular cooling element described above. Preferably, the hollow tubular support element abuts against the downstream end of the rod of the aerosol generating substrate. Preferably, the hollow tubular support element abuts against the upstream end of the hollow tubular cooling element. It is preferable that 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.

[0301] 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 sulfuric acid paper), and polymer materials (such as low-density polyethylene (LDPE)). In a preferred embodiment, the support element is formed from cellulose acetate. Other preferred materials include polyhydroxyalkanoate (PHA) fibers. In a preferred embodiment, the hollow tubular support element includes a hollow acetate tube.

[0302] The hollow tubular support element preferably has an outer diameter that is approximately equal to the outer diameter of the rod of the aerosol generating substrate and the outer diameter of the aerosol generating article.

[0303] The hollow tubular support 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 support element has an outer diameter less than 7 millimeters.

[0304] 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.

[0305] The hollow tubular support element may have a length of at least 5 millimeters. Preferably, the support element has a length of at least 6 millimeters, more preferably at least about 7 millimeters.

[0306] The hollow tubular support element may have a length less than 15 millimeters. Preferably, the hollow tubular support element has a length less than 12 millimeters, more preferably less than 10 millimeters.

[0307] In some embodiments, the support element has a length of 5 millimeters to 15 millimeters, preferably 6 millimeters to 15 millimeters, more preferably 7 millimeters to 15 millimeters. In other embodiments, the support element has a length of 5 millimeters to 12 millimeters, preferably 6 millimeters to 12 millimeters, more preferably 7 millimeters to 12 millimeters. In further embodiments, the support element has a length of 5 millimeters to 10 millimeters, preferably 6 millimeters to 10 millimeters, more preferably 7 millimeters to 10 millimeters.

[0308] Preferably, the length of the hollow tubular section is at least 20 millimeters. More preferably, the length of the hollow tubular section is at least 30 millimeters. The length of the hollow tubular section may be at least 40 millimeters. More preferably, the length of the hollow tubular section is at least 45 millimeters.

[0309] The length of the hollow tubular section is preferably less than 60 millimeters. The length of the hollow tubular section is more preferably less than 55 millimeters. The length of the hollow tubular section is more preferably less than 50 millimeters.

[0310] For example, the length of the hollow tubular section may be 20 to 60 mm, or 30 to 60 mm, or 40 to 60 mm, or 45 to 60 mm. In other embodiments, the length of the hollow tubular section may be 20 to 55 mm, or 30 to 55 mm, or 40 to 55 mm, or 45 to 55 mm. In other embodiments, the length of the hollow tubular section may be 20 to 50 mm, or 30 to 50 mm, or 40 to 50 mm, or 45 to 50 mm.

[0311] As an alternative to, or in addition to, 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 also preferably, the downstream hollow tubular element is separated from the hollow tubular cooling element by at least one other component. For example, the downstream section may comprise a downstream filter segment between the hollow tubular cooling element and the downstream hollow tubular element. Thus, it is preferable that the downstream hollow tubular element is located downstream of the downstream filter segment and that the downstream hollow tubular element abuts the downstream end of the downstream filter segment.

[0312] The downstream hollow tubular element preferably extends to the downstream end of the downstream section. Therefore, it is preferable that the downstream hollow tubular element extends to the downstream end of the aerosol generating article. In certain embodiments, additional downstream hollow tubular elements may be provided such that the downstream section comprises two adjacent downstream hollow tubular elements downstream of the downstream filter segment.

[0313] The RTD of the downstream hollow tubular element is preferably 10 mmH2O or less. More preferably, the RTD of the downstream hollow tubular element is 5 mmH2O or less. Even more preferably, the RTD of the downstream hollow tubular element is 2.5 mmH2O or less. Even more preferably, the RTD of the downstream hollow tubular element is 2 mmH2O or less. Even more preferably, the RTD of the downstream hollow tubular element is 1 mmH2O or less.

[0314] The RTD of the downstream hollow tubular element may be at least 0 mmH2O, or at least 0.25 mmH2O, or at least 0.5 mmH2O, or at least 1 mmH2O.

[0315] In some preferred embodiments, the RTD of the downstream hollow tubular element is 0 mmH2O to 10 mmH2O, preferably 0.25 mmH2O to 10 mmH2O, and more preferably 0.5 mmH2O to 10 mmH2O. In other embodiments, the RTD of the downstream hollow tubular element is 0 mmH2O to 5 mmH2O, preferably 0.25 mmH2O to 5 mmH2O, and more preferably 0.5 mmH2O to 5 mmH2O. In yet another embodiment, the RTD of the downstream hollow tubular element is 1 mmH2O to 5 mmH2O. In a further embodiment, the RTD of the downstream hollow tubular element is 0 mmH2O to 2.5 mmH2O, preferably 0.25 mmH2O to 2.5 mmH2O, and more preferably 0.5 mmH2O to 2.5 mmH2O. In further embodiments, the RTD of the downstream hollow tubular element is 0 mmH2O to 2 mmH2O, preferably 0.25 mmH2O to 2 mmH2O, and more preferably 0.5 mmH2O to 2 mmH2O. In one particularly preferred embodiment, the RTD of the downstream hollow tubular element is 0 mmH2O.

[0316] Therefore, the airflow channel of the downstream hollow tubular element should not contain any components that would obstruct the airflow in the longitudinal direction. The flow channel is preferably substantially empty, and particularly preferably empty.

[0317] The length of the downstream hollow tubular element is preferably 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.

[0318] The length of the downstream hollow tubular element is preferably less than 20 millimeters. More preferably less than 15 millimeters. More preferably less than 12 millimeters. More preferably less than 10 millimeters.

[0319] For example, the length of the downstream hollow tubular element may be 3 to 20 millimeters, or 4 to 20 millimeters, or 5 to 20 millimeters, or 6 to 20 millimeters. In other embodiments, the length of the downstream hollow tubular element may be 3 to 15 millimeters, 4 to 15 millimeters, 5 to 15 millimeters, or 6 to 15 millimeters. In other embodiments, the length of the downstream hollow tubular element may be 3 to 12 millimeters, 4 to 12 millimeters, or 5 to 12 millimeters, or 6 to 12 millimeters. In other embodiments, the length of the downstream hollow tubular element may be 3 to 10 millimeters, or 4 to 10 millimeters, or 5 to 10 millimeters, or 6 to 10 millimeters.

[0320] 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 (or multiple elements) is preferably at least 20 millimeters. This corresponds to the sum of the lengths of the hollow tubular cooling element and the downstream hollow tubular element (or multiple elements), without considering the length of any components provided in between. The combined length is more preferably at least 30 millimeters. The combined length may be at least 40 millimeters. The combined length is more preferably at least 45 millimeters.

[0321] The combined length of the hollow tubular cooling element and the downstream hollow tubular element (or multiple elements) is preferably less than 60 millimeters. More preferably, the combined length is less than 55 millimeters. More preferably, the combined length is less than 50 millimeters.

[0322] For example, the combined length of the hollow tubular cooling element and the downstream hollow tubular element (or multiple elements) may be 20 to 60 mm, or 30 to 60 mm, or 40 to 60 mm, or 45 to 60 mm. In other embodiments, the combined length may be 20 to 55 mm, or 30 to 55 mm, or 40 to 55 mm, or 45 to 55 mm. In other embodiments, the combined length may be 20 to 50 mm, or 30 to 50 mm, or 40 to 50 mm, or 45 to 50 mm.

[0323] By providing combined lengths within the above-mentioned range, the overall length of the hollow tubular elements in the downstream section is relatively long, and the above-mentioned advantages are obtained with respect to the length of the hollow tubular cooling elements.

[0324] 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.

[0325] The downstream hollow tubular element may contain a paper-based material. The downstream hollow tubular element may contain at least one layer of paper. The paper may be very rigid paper. The paper may be crimped paper such as crimped heat-resistant paper or crimped sulfuric acid paper.

[0326] The downstream hollow tubular element may include cardboard. The downstream hollow tubular element can be a cardboard tube.

[0327] The downstream hollow tubular element may be a paper tube. The downstream hollow tubular element may be a tube formed from spirally wound paper. The downstream hollow tubular 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.

[0328] The downstream hollow tubular element may contain polymer materials. For example, the downstream hollow tubular element may contain a polymer film. The polymer film may contain a cellulose film. The downstream hollow tubular element may contain low-density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers. Preferably, the downstream hollow tubular element comprises a cellulose acetate tube. For example, in a preferred embodiment, the downstream hollow tubular element contains a hollow acetate tube.

[0329] If the downstream hollow tubular element contains cellulose acetate tow, the cellulose acetate tow may have 2 to 4 denier per filament and a total denier of 25 to 40.

[0330] If the downstream section further comprises the additional downstream hollow tubular elements described above, the additional downstream hollow tubular elements may be formed of the same material as the downstream hollow tubular elements, or of a different material.

[0331] In certain preferred embodiments, the downstream section may include a ventilation zone at a location on the downstream hollow tubular element. In one embodiment, this ventilation zone at a location on the downstream hollow tubular element may be provided instead of a ventilation zone at a location on the hollow tubular cooling element. In another embodiment, the ventilation zone at a location on the downstream hollow tubular element may be provided in addition to a ventilation zone provided at a location on the hollow tubular cooling element.

[0332] The ventilation zone along the downstream hollow tubular element may include a plurality of perforations passing through the peripheral wall of the downstream hollow tubular element. Preferably, the ventilation zone along the downstream hollow tubular element includes at least one circumferential row of perforations. In some embodiments, the ventilation zone may include two circumferential rows of perforations. For example, the perforations may be formed online during the manufacture of the aerosol-generating article. Preferably, each circumferential row of perforations includes 8 to 30 perforations.

[0333] 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.

[0334] The distance between the ventilation zone and the upstream end of the downstream hollow tubular element is preferably 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.

[0335] In some embodiments, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is 1 to 10 millimeters, preferably 1 to 7 millimeters, and more preferably 1 to 5 millimeters. In further embodiments, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is 2 to 10 millimeters, preferably 2 to 7 millimeters, and more preferably 2 to 5 millimeters. In other embodiments, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is 3 to 10 millimeters, preferably 3 to 7 millimeters, and more preferably 3 to 5 millimeters.

[0336] Positioning the ventilation zone within the aforementioned range from the upstream end of the downstream hollow tubular element has the advantage that, when an aerosol-generating article is inserted into the heating device during use, the ventilation zone is located just outside the heating device, and the risk of the ventilation zone being accidentally blocked by the user's lips or hands is generally ensured.

[0337] The downstream section may optionally further include additional cooling elements that define multiple longitudinally extending channels, for example, 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. Multiple longitudinally extending channels may be defined by a sheet material that has been processed to crimp, assemble, or fold in order to form the channels. Multiple longitudinally extending channels may be defined by a single sheet that has been processed to crimp, assemble, or fold in order to form the multiple channels. The sheet may also be crimped before being crimped, assembled, or folded. Alternatively, multiple longitudinally extending channels may be defined by multiple sheets that have been crimped, crimped, assembled, or fold in order to form the multiple channels. In some embodiments, multiple longitudinally extending channels may be defined by multiple sheets that are crimped, pleated, assembled, or folded, i.e., brought into an overlay arrangement and then defined by two or more sheets that are crimped, pleated, assembled, or folded as a single entity.

[0338] As used herein, the term “crimp” means a sheet having a plurality of substantially parallel ridges or wavy patterns. When an aerosol-generating article is assembled, the substantially parallel ridges or wavy patterns preferably extend longitudinally with respect to the rod. As used herein, the terms “assemble,” “fold,” or “fold” mean that a sheet of material is spiraled, folded, or otherwise compressed or shrunk substantially transversely with respect to the cylindrical axis of the rod. The sheet may be crimped before being assembled, folded, or folded. The sheet may be assembled, folded, or folded without prior crimping.

[0339] One such additional cooling element may have a total surface area of ​​approximately 300 square millimeters per millimeter of length to approximately 1,000 square millimeters per millimeter of length.

[0340] The additional cooling element preferably provides low draw resistance to the passage of air through it. Preferably, the additional cooling element does not substantially affect the draw resistance of the aerosol-generating article. To achieve this, it is preferable that the longitudinal porosity is greater than 50 percent and that the airflow path through the additional cooling element is relatively unrestricted. The longitudinal porosity of the additional cooling element can 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 containing the additional cooling element.

[0341] Additional cooling elements include sheet materials selected from the group consisting of metal foil, polymer sheets, and substantially non-porous paper or cardboard. In some embodiments, the aerosol cooling element may include sheet materials selected from the group consisting of polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polylactic acid (PLA), cellulose acetate (CA), and aluminum foil. In a particularly preferred embodiment, the additional cooling element includes a sheet of PLA.

[0342] The aerosol-generating article may have a total length of 45 mm to 100 mm.

[0343] Preferably, the total length of the aerosol generating article according to the present invention is at least 50 millimeters. More preferably, the total length of the aerosol generating article according to the present invention is at least 60 millimeters. Even more preferably, the total length of the aerosol generating article according to the present invention is at least 70 millimeters.

[0344] The total length of the aerosol generating article according to the present invention is preferably 90 millimeters or less. More preferably, the total length of the aerosol generating article according to the present invention is preferably 85 millimeters or less. Even more preferably, the total length of the aerosol generating article according to the present invention is preferably 80 millimeters or less.

[0345] In some embodiments, the total length of the aerosol-generating article is preferably 50 to 90 millimeters, more preferably 60 to 90 millimeters, and even more preferably 70 to 90 millimeters. In other embodiments, the total length of the aerosol-generating article is preferably 50 to 85 millimeters, more preferably 60 to 85 millimeters, and even more preferably 70 to 85 millimeters. In further embodiments, the total length of the aerosol-generating article is preferably 50 to 80 millimeters, more preferably 60 to 80 millimeters, and even more preferably 70 to 80 millimeters. In an exemplary embodiment, the total length of the aerosol-generating article is 75 millimeters.

[0346] The aerosol-generating article preferably has an outer diameter of at least 5 millimeters along its entire length. If the diameter varies along the length of the aerosol-generating article, the outer diameter is preferably at least 5 millimeters at all points along the length of the article.

[0347] The aerosol-generating article preferably has an outer diameter of at least 5.5 mm along its entire length. More preferably, the aerosol-generating article has an outer diameter of at least 6 mm along its entire length.

[0348] 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 changes along the length of the article, the diameter at all points along the length is less than 10 millimeters. 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.

[0349] In some embodiments, the aerosol-generating article has an outer diameter of 5 mm to 10 mm, preferably 5.5 mm to 10 mm, and 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, and more preferably 6 mm to 9 mm. In further embodiments, the aerosol-generating article has an outer diameter of 5 mm to 8 mm, preferably 5.5 mm to 8 mm, and more preferably 6 mm to 8 mm. In even further embodiments, the aerosol-generating article has an outer diameter of 5 mm to 7 mm, preferably 5.5 mm to 7 mm, and more preferably 6 mm to 7 mm.

[0350] The outer diameter of an aerosol-generating article may be substantially constant along its entire length. Alternatively, different parts of the aerosol-generating article may have different outer diameters.

[0351] In a particularly preferred embodiment, one or more components of the aerosol-generating article are individually surrounded by their own wrappers.

[0352] In one embodiment, the aerosol generating substrate rod and the downstream filter segment are wound separately. The upstream element, the aerosol generating substrate rod, and the hollow tubular element are then combined with an outer wrapper. They are then combined with the downstream filter segment, which has its own wrapper, by chipping paper.

[0353] Preferably, at least one of the components of the aerosol-generating article is wrapped in a hydrophobic wrapper.

[0354] The term "hydrophobic" refers to a surface that exhibits water-repellent properties. One useful way to determine this is by measuring the water contact angle. The water contact angle is the angle conventionally measured through a liquid, where the liquid / vapor interface intersects with the solid surface. This quantifies the wettability of a solid surface by a liquid via Young's equation. Hydrophobicity or the water contact angle may also be determined using the TAPPI T558 test method, and the result is expressed as the interfacial contact angle and reported in degrees, which can range from approximately zero to approximately 180 degrees.

[0355] In a preferred embodiment, the hydrophobic wrapper includes a paper layer having a water contact angle of about 30 degrees or more, preferably about 35 degrees or more, or about 40 degrees or more, or about 45 degrees or more.

[0356] For example, the paper layer may contain PVOH (polyvinyl alcohol) or silicon. PVOH may be applied to the paper layer as a surface coating, or the paper layer may include a surface treatment containing PVOH or silicon.

[0357] In a particularly preferred embodiment, the aerosol generating article according to the present invention comprises, in a linear and continuous arrangement, an upstream element, a rod of an aerosol generating substrate located immediately downstream of the upstream element, a hollow tubular cooling element located immediately downstream of the rod of the 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, the downstream filter segment, and the downstream hollow tubular element form the downstream section of the aerosol generating article.

[0358] The rod of the aerosol generating substrate may be in contact with the upstream element. The hollow tubular cooling element may be in contact with the rod of the aerosol generating substrate. The downstream filter segment may be in contact with the hollow tubular cooling element. The downstream hollow tubular element may be in contact with the downstream filter segment. It is preferable that the hollow tubular cooling element is in contact with the rod of the aerosol generating substrate, the downstream filter segment is in contact with the hollow tubular cooling element, and the downstream hollow tubular element is in contact with the downstream filter segment.

[0359] This disclosure also relates to an aerosol generating system comprising an aerosol generating device having a distal end and an oral end. The aerosol generating device may comprise a body. The body or housing of the aerosol generating device may define a device cavity at the oral end of the device for removably receiving an aerosol generating article. The aerosol generating device may comprise a heating element or heater for heating the aerosol generating substrate when the aerosol generating article is received in the device cavity.

[0360] The device cavity may also be called the heating chamber of the aerosol generator. The device cavity may extend between a distal end and a mouth (or proximal) end. The distal end of the device cavity may be a closed end, and the mouth (or proximal) end 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 accommodate the same shape as the aerosol generating article.

[0361] The expression "internal acceptance" may refer to the fact that a component or element is fully or partially accepted within another component or element. For example, the expression "an aerosol-generating article is accepted within the device cavity" means that the aerosol-generating article is fully or partially accepted within the device cavity of the aerosol-generating article. When an aerosol-generating article is accepted within the device cavity, it may abut against the distal end of the device cavity. When an aerosol-generating article is accepted within the device cavity, it may be substantially close to the distal end of the device cavity. The distal end of the device cavity may be defined by an end wall.

[0362] The length of the device cavity may be 10 mm to 50 mm. The length of the device cavity may be 20 mm to 40 mm. The length of the device cavity may be 25 mm to 30 mm.

[0363] 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 at least 75 percent of the length of the rod of the aerosol generating substrate is inserted into or received within the device cavity when the aerosol generating article is received together with the aerosol generating device. More preferably, the length of the device cavity is such that at least 80 percent of the length of the rod of the aerosol generating substrate is inserted into or received within the device cavity when the aerosol generating article is received together with the aerosol generating device. More preferably, the length of the device cavity is such that at least 90 percent of the length of the rod of the aerosol generating substrate is inserted into or received within the device cavity when the aerosol generating article is received together with the aerosol generating device. This maximizes the length of the rod of the aerosol generating substrate that can be heated during use, thereby optimizing aerosol generation from the aerosol generating substrate and reducing tobacco waste.

[0364] The length of the device cavity may be such that when the aerosol-generating article is received into 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 the aerosol-generating article is received into the device cavity, a portion of the downstream section (such as a hollow tubular cooling element or a downstream filter segment) protrudes from the device cavity. The length of the device cavity may be such that when the aerosol-generating article is received into the device cavity, a portion of the downstream section (such as a hollow tubular cooling element or a downstream filter segment) is received into the device cavity.

[0365] At least 25 percent of the length of the downstream section may be inserted into 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 into or received within the device cavity when the aerosol-generating article is received within the device.

[0366] At least 30 percent of the length of the hollow tubular element may be inserted into 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 into 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 into or received within the device cavity when the aerosol-generating article is received within the device. Various lengths of the hollow tubular element are described in more detail within this disclosure.

[0367] Optimizing the quantity or length of articles inserted into an aerosol generator may increase resistance to accidental dislodgement of articles during use. In particular, during heating of the aerosol generating substrate, the substrate may shrink, thereby reducing its outer diameter, which in turn reduces the degree to which the inserted portion of an article can frictionally engage with the device cavity. The inserted portion of an article, or the portion of an article configured to be received within the device cavity, may be the same length as the device cavity.

[0368] The length of the device cavity may be 15 mm to 80 mm. Preferably, the length of the device cavity is 20 mm to 70 mm. More preferably, the length of the device cavity is 25 mm to 60 mm. More preferably, the length of the device is 25 mm to 50 mm.

[0369] The length of the device cavity may be 25 to 29 millimeters. Preferably, the device cavity length is 25 to 29 millimeters. More preferably, the device cavity length is 26 to 29 millimeters. Even more preferably, the device cavity length is 27 or 28 millimeters.

[0370] The diameter of the device cavity may be 4 mm to 10 mm. The diameter of the device cavity may be 5 mm to 9 mm. The diameter of the device cavity may be 6 mm to 8 mm. The diameter of the device cavity may be 6 mm to 7 mm.

[0371] The diameter of the device cavity may be substantially the same as, or larger than, the diameter of the aerosol generating article. The diameter of the device cavity may be the same as the diameter of the aerosol generating article in order to establish a tight fit with the aerosol generating article.

[0372] The device cavity may be configured to establish a tight fit with the aerosol generating article received within the device cavity. A tight fit may refer to a sliding fit. The aerosol generating device may have peripheral walls. Such peripheral walls may define the device cavity or heating chamber. Peripheral walls defining the device cavity may be configured to engage in a tight fit with the 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 walls defining the device cavity and the aerosol generating article.

[0373] Such airtight fittings can establish an airtight fit or configuration between the device cavity and the aerosol-generating article received therein.

[0374] In such an airtight configuration, there is virtually no gap or empty space between the surrounding walls that define the device cavity and the aerosol-generating article through which air flows.

[0375] 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.

[0376] The aerosol generator may include airflow channeling extending between a channel inlet and a channel outlet. The airflow channel may be configured to establish fluid communication between the inside of the device cavity and the outside of the aerosol generator. The airflow channel of the aerosol generator may be defined within the housing of the aerosol generator to enable fluid communication between the inside of the device cavity and the outside of the aerosol generator. When an aerosol-generating article is received in the device cavity, the airflow channel may be configured to provide air flowing into the article to deliver the generated aerosol to a user who inhales it from the mouth end of the article.

[0377] The airflow channels of the aerosol generator may be defined within or by the peripheral walls of the housing of the aerosol generator. In other words, the airflow channels of the aerosol generator may be defined within the thickness of the peripheral walls, by the inner surfaces of the peripheral walls, or a combination of both. The airflow channels may be partially defined by the inner surfaces of the peripheral walls, or partially defined within the thickness of the peripheral walls. The inner surfaces of the peripheral walls define the periphery of the device cavity.

[0378] The airflow channel of the aerosol generator may extend from an inlet located at the mouth end or proximal end of the aerosol generator to an outlet located away from the mouth end of the device. The airflow channel may extend along a direction parallel to the longitudinal axis of the aerosol generator.

[0379] The heater may be any suitable type of heater. In the present invention, the heater is preferably an external heater.

[0380] Preferably, the heater may externally heat the aerosol generating article when it is received inside the aerosol generator. Such an external heater may surround the aerosol generating article when it is inserted into or received inside the aerosol generator.

[0381] In some embodiments, the heater is positioned to heat the outer surface of the aerosol generating substrate. In some embodiments, the heater is positioned for insertion into the aerosol generating substrate when the aerosol generating substrate is received within a cavity. The heater may be located within the apparatus cavity or heating chamber.

[0382] The heater may comprise at least one heating element. The at least one heating element can be any suitable type of heating element. In some embodiments, the device comprises only one heating element. In some embodiments, the device comprises 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 can facilitate the 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 can facilitate reducing or minimizing the physical size of the power supply.

[0383] Suitable materials for forming at least one resistance heating element include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilide), carbon, graphite, metals, metal alloys, and composite materials made of ceramic and metal materials. Such composite materials may include doped or undoped ceramics. A suitable example of a doped ceramic is doped silicon carbide. Suitable metals include titanium, zirconium, tantalum, and platinum group metals. Suitable metal alloys include stainless steel, nickel-containing, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, and iron-containing alloys, as well as nickel, iron, cobalt, stainless steel-based superalloys, Timetal®, and iron-manganese-aluminum alloys.

[0384] In some embodiments, at least one resistive heating element includes one or more stamped portions of an electrically resistive material (such as stainless steel). Alternatively, at least one resistive heating element may include a heating wire or filament (e.g., Ni-Cr (nickel-chromium), platinum, tungsten, or alloy wire).

[0385] In some embodiments, at least one heating element includes an electrically insulated substrate, and at least one resistance heating element is provided on an electrically insulated substrate.

[0386] The electrically insulated substrate may include any suitable material. For example, the electrically insulated substrate may include one or more of paper, glass, ceramic, anodized metal, coated metal, and polyimide. The ceramic may include mica, alumina (Al2O3), or zirconia (ZrO2). The electrically insulated substrate preferably has a thermal conductivity of about 40 watts / meter Kelvin or less, preferably about 20 watts / meter Kelvin or less, and ideally about 2 watts / meter Kelvin or less.

[0387] The heater may comprise a heating element including a rigid, electrically insulated substrate having one or more conductive tracks or wires arranged on its surface. The size and shape of the electrically insulated substrate may allow the heater to be directly inserted into the aerosol generating substrate. If the electrically insulated substrate is not sufficiently rigid, the heating element may include further reinforcing means. Current may pass through one or more conductive tracks to heat the heating element and the aerosol generating substrate.

[0388] In some embodiments, the heater comprises an induction heating arrangement. The induction heating device may comprise an inductor coil and a power supply configured to supply a high-frequency oscillating current to the inductor coil. As used herein, a high-frequency oscillating current means an oscillating current having a frequency of about 500 kHz to about 30 MHz. The heater may advantageously comprise a DC / AC inverter for converting the DC current supplied by the DC power supply into an AC current. The inductor coil may be arranged to generate a high-frequency oscillating electromagnetic field upon receiving a high-frequency oscillating current from the power supply. 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 enclose the device cavity. The inductor coil may extend at least partially along the length of the device cavity.

[0389] The heater may include an inductive heating element. The inductive heating element may be a susceptor element. As used herein, the term “susceptor element” refers to an element comprising a material having the ability to convert electromagnetic energy into heat. When a susceptor element is located in an alternating electromagnetic field, the susceptor is heated. The 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 properties and magnetism of the susceptor material.

[0390] The susceptor element may be arranged such that, when an aerosol-generating article is received within the cavity of the aerosol generator, the oscillating electromagnetic field generated by the inductor coil induces a current within the susceptor element, thereby heating the susceptor element. In these embodiments, the aerosol generator is preferably capable of generating a fluctuating electromagnetic field having a magnetic field strength (H-field strength) of 1 to 5 kiloamperes / meter (kA / m), preferably 2 to 3 kA / m, for example, about 2.5 kA / m. The electrically operated aerosol generator is preferably capable of generating a fluctuating electromagnetic field having a frequency of 1 to 30 MHz, for example, 1 to 10 MHz, for example, 5 to 7 MHz.

[0391] In these embodiments, the susceptor element is preferably located in contact with the aerosol generating substrate. In some embodiments, the susceptor element is located inside the aerosol generator. In these embodiments, the susceptor element may be located inside a cavity. The aerosol generator may include only one susceptor element. The aerosol generator may include multiple susceptor elements. In some embodiments, the susceptor element is preferably arranged to heat the outer surface of the aerosol generating substrate.

[0392] The susceptor element may contain any suitable material. The susceptor element 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 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 contain metal or carbon. Advantageously, the susceptor element may contain or consist of ferromagnetic materials such as ferrite iron, ferromagnetic alloys such as ferromagnetic steel or stainless steel, ferromagnetic particles, and ferrite. A suitable susceptor element may be aluminum, or may contain aluminum. The susceptor element preferably contains more than about 5 percent, preferably more than 20 percent, more preferably more than 50 percent, or more than 90 percent of ferromagnetic or paramagnetic material. Some elongated susceptor elements can be heated to temperatures above 250 degrees Celsius.

[0393] The susceptor element may comprise a non-metallic core having a metal layer arranged on top of the non-metallic core. For example, the susceptor element may include a metal track formed on the outer surface of a ceramic core or substrate.

[0394] In some embodiments, the aerosol generator may comprise at least one resistance heating element and at least one induction heating element. In some embodiments, the aerosol generator may comprise a combination of a resistance heating element and an induction heating element.

[0395] During use, the heater can be controlled to operate within a specified operating temperature range below the maximum operating temperature. The operating temperature range within the heating chamber (or device cavity) is preferably about 150°C to about 300°C. The operating temperature range of the heater may be about 150°C to about 250°C.

[0396] Preferably, the heater's operating temperature range may be between approximately 150°C and approximately 200°C. More preferably, the heater's operating temperature range may be between approximately 180°C and approximately 200°C. Specifically, it has been found that optimal and consistent aerosol delivery can be achieved when using an aerosol generating article having a relatively low RTD (e.g., having an RTD in the downstream section of less than 15 mmH2O) as described in this disclosure, and using an aerosol generating device having an external heater with an operating temperature range of approximately 180°C to approximately 200°C.

[0397] In embodiments where the aerosol generating article has a ventilation zone located along a downstream section or a hollow tubular element, the ventilation zone may be arranged to be exposed when the aerosol generating article is received within the device cavity. Therefore, 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.

[0398] When an article is received in the device cavity, the ventilation zone may be located at least 0.5 millimeters away from the opening end (or opening end face) of the device cavity or the device itself (in the downstream direction of the article). When an article is received in the device cavity, the ventilation zone may be located at least 1 millimeter away from the opening end (or opening end face) of the device cavity or the device itself (in the downstream direction of the article). When an article is received in the device cavity, the ventilation zone may be located at least 2 millimeters away from the opening end (or opening end face) of the device cavity or the device itself (in the downstream direction of the article).

[0399] The ratio of the distance between the ventilation zone and the upstream end of the upstream element to the length of the heating chamber is preferably 1.03 to 1.13.

[0400] This placement of the ventilation zone ensures that it is not blocked within the device cavity itself, while also minimizing the risk of blockage by the user's lips or hands, as it is located at the upstream end from the downstream end of the article, allowing for reasonable ventilation without being blocked within the device cavity.

[0401] The aerosol generator may be equipped with a power supply. The power supply may be a DC power supply. In some embodiments, the power supply is a battery. The power supply 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 supply may be another form of charge storage device, such as a capacitor. The power supply may require recharging and may have a capacity that allows for sufficient energy storage for one or more user operations, such as one or more aerosol generation experiences. For example, the power supply may have a capacity sufficient to enable continuous heating of the aerosol generating substrate for about six minutes, or a multiple of six minutes, corresponding to the typical time it takes to smoke one conventional cigarette. In another embodiment, the power supply may have a capacity sufficient to enable a predetermined number of puffs or discontinuous starts of the heater.

[0402] [Examples] A non-exclusive list of non-limiting embodiments is provided below. One or more features of these embodiments may be combined with any one or more features of other embodiments, forms, or aspects described herein.

[0403] Example 1. An aerosol generating article, including a rod of an aerosol generating substrate. Example 2. The aerosol generating article according to Example 1, wherein the rod of the aerosol generating substrate has a length of at least 17 millimeters. Example 3. An aerosol generating article according to any one of Examples 1 to 2, wherein the rod of the aerosol generating substrate contains tobacco material. Example 4. The aerosol-generating article according to Example 3, wherein the tobacco material has a density of less than 350 milligrams per cubic centimeter. Example 5. The aerosol-generating article according to Example 4, wherein the tobacco material has a density of less than 300 milligrams per cubic centimeter. Example 6. An aerosol-generating article according to Example 3, 4, or 5, wherein the tobacco material has a density of at least 100 milligrams per cubic centimeter. Example 7. The aerosol-generating article according to Example 3, wherein the tobacco material has a density of 150 milligrams per cubic centimeter to 500 milligrams per cubic centimeter. Example 8. The aerosol-generating article according to Example 7, wherein the tobacco material has a density of 200 milligrams per cubic centimeter to 400 milligrams per cubic centimeter. Example 9. An aerosol generating article according to any one of Examples 1 to 8, comprising a downstream section provided downstream of the rod of an aerosol generating substrate. Example 10. The aerosol generating article according to Example 9, wherein the downstream section comprises a hollow tubular element that abuts against the downstream end of the rod of the aerosol generating substrate. Example 11. The aerosol generating article according to Example 10, wherein the hollow tubular element has a length of at least 40 millimeters. Example 12. The aerosol-generating article according to Example 9, wherein the downstream section includes a downstream filter segment. Example 13. The aerosol-generating article according to Example 12, wherein the downstream section has a ventilation zone located downstream of the downstream filter segment. Example 14. The aerosol generating article according to Example 12 or 13, wherein the downstream filter segment is a solid plug. Example 15. An aerosol generating article according to any one of Examples 12 to 14, comprising a downstream hollow tubular element, wherein the downstream tubular element is located downstream of the downstream filter segment. Example 16. The aerosol generating article according to Example 15, wherein the downstream hollow tubular element abuts against the downstream end of the downstream filter segment. Example 17. The aerosol-generating article according to Example 15 or 16, wherein the ventilation zone is located along the downstream hollow tubular element. Example 18. The aerosol generating article according to Example 17, wherein the ventilation zone is located toward the upstream end of the downstream hollow tubular element. Example 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 against the downstream end of the hollow tubular cooling element. Example 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. 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. An aerosol generating article according to either Example 12 or 21, wherein the downstream filter segment has a length of 5 mm to 20 mm. Example 23. The aerosol generating article according to Example 9, wherein the downstream section extends to the downstream end of the aerosol generating article. Example 24. The aerosol generating article according to Example 9 or 23, wherein the downstream section comprises a hollow tubular cooling element. Example 25. The aerosol generating article according to Example 24, wherein the hollow tubular cooling element has a length of at least 20 millimeters. Example 26. The aerosol generating article according to Example 25, wherein the hollow tubular cooling element has a length of at least 25 millimeters. Example 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 mm or less. Example 28. The aerosol generating article according to Example 27, wherein the hollow tubular cooling element has a length of 20 mm to 50 mm. Example 29. An aerosol-generating article according to Example 9, or any one of Examples 23-26, wherein the downstream section has a length of at least 45 millimeters. Example 30. An aerosol generating article according to any of Examples 1 to 29, wherein the maximum outer diameter of the aerosol generating article is less than 8 millimeters. Example 31. The aerosol generating article according to Example 30, wherein the aerosol generating article has a maximum outer diameter of 5 mm to 8 mm. Example 32. The aerosol generating article according to Example 30 or 31, wherein the aerosol generating article has a maximum outer diameter of 7 mm or less. Example 33. The aerosol generating article according to Example 32, wherein the aerosol generating article has a maximum outer diameter of 5.5 mm to 7 mm. Example 34. The aerosol generating article according to 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. The aerosol generating article according to Example 9, wherein the ratio of the length of the downstream section to the total length of the aerosol generating article is at least 0.6. Example 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 of Examples 1 to 36, wherein the rod of the aerosol generating substrate has a length of 40 millimeters or less. Example 38. The aerosol generating article according to 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 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 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 total 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 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. The aerosol generating article according to Example 48, wherein the upstream element is provided upstream of the rod of the aerosol generating substrate. Example 50. The aerosol generating article according to Example 48 or 49, wherein the upstream element is provided in contact with the upstream end of the rod of the aerosol generating substrate. Example 51. An aerosol generating article according to any one of Examples 48 to 50, wherein the upstream element has a length of 2 mm to 8 mm. Example 52. An aerosol generating article according to any one of Examples 48 to 51, wherein the upstream element has a length of 2 mm to 6 mm. Example 53. An aerosol generating article according to any one of Examples 48 to 52, wherein the upstream element has a length of 4 mm to 6 mm. 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 through it. Example 55. The aerosol generating article according to Example 54, wherein the hollow tubular support element has a wall thickness of less than 1 millimeter. Example 56. An aerosol generating article according to one of Examples 48 to 55, wherein the upstream element drawout resistance (RTD) is 10 mmH2O or less. Example 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. The aerosol generating article according to Example 57, wherein the aerosol generating article has a total length of at least 65 millimeters. Example 59. An aerosol generating article according to any of Examples 1 to 58, wherein the aerosol generating article has a total length of 90 mm or less. Example 60. An aerosol generating article according to any of Examples 1 to 59, wherein the aerosol generating article has a total length of 65 mm to 90 mm. Example 61. An aerosol generating article according to any one of Examples 1 to 60, wherein the rod of the aerosol generating substrate includes one or more aerosol forming bodies. Example 62. The aerosol generating article according to Example 61, wherein the rod of the aerosol generating substrate has an aerosol forming material content of 30% by weight or less on a dry weight basis. Example 63. The aerosol generating article according to Example 62, wherein the rod of the aerosol generating substrate has an aerosol forming material content of 20% by weight or less on a dry weight basis. Example 64. The aerosol generating article according to Example 63, wherein the rod of the aerosol generating substrate has an aerosol forming material content of 10% by weight or less on a dry weight basis. Example 65. The aerosol generating article according to Example 62, wherein the rod of the aerosol generating substrate has an aerosol forming material content of 10% to 30% by weight on a dry weight basis. Example 66. An aerosol generating article according to any one of Examples 61 to 65, wherein one or more aerosol-forming bodies contain one or more of glycerin and propylene glycol. Example 67. An aerosol generating article according to any 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 0.01 to 0.15. Example 68. An aerosol-generating article according to any one of Examples 3 to 67, wherein the tobacco material includes shredded tobacco material. Example 69. An aerosol generating article according to any one of Examples 1 to 68, wherein the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article is at least 0.2, preferably 0.25. Example 70. Aerosol generation system, an aerosol generating article described in any of Examples 1 to 69, An aerosol generating system comprising a heating chamber for receiving an aerosol generating article, and at least one heating element provided around or near the heating chamber.

[0404] The present invention will be further described below with reference to the attached drawings.

[0405] The aerosol generating article shown in all figures of this disclosure comprises a rod 12 of an aerosol generating substrate and a downstream section 14 located downstream of the rod 12 of the aerosol generating substrate. The aerosol generating article extends from an upstream or distal end 18 to a downstream or oral end 19. The downstream or oral end 19 is defined by the downstream end of the downstream section 14.

[0406] Each component of the aerosol-generating article shown in the figure and described herein may be enclosed by a corresponding wrapper, or may be joined together by one or more wrappers not shown in the figure. Unless otherwise specified, the maximum outer diameter of each of the aerosol-generating articles shown in the figure is approximately 6.5 mm.

[0407] The rod 12 of the aerosol generating substrate is surrounded by a wrapper (not shown) and includes at least one type of aerosol generating substrate as described herein, such as plant cut filler, in particular tobacco cut filler, homogenized tobacco, gel formulation, or homogenized plant material containing particles of plants other than tobacco. The rod 12 of the aerosol generating article shown in all figures has an average tobacco density of about 250 mg per cubic centimeter.

[0408] 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 the 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 against the downstream end of the rod 12. The downstream filter segment 24 abuts against the downstream end of the hollow tubular cooling element 22, and the downstream hollow tubular element 26 abuts against 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.

[0409] The length of the rod 12 of the aerosol generating substrate is approximately 40 mm.

[0410] 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 internal cavity that extends throughout the entire length from the upstream end to the downstream end of the hollow tubular cooling element 22. The internal cavity is substantially empty, and thus allows for substantially unrestricted airflow along the internal cavity. The hollow tubular cooling element 22 can not substantially contribute 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).

[0411] The downstream filter segment 24 is equipped with a cylindrical plug made of cellulose acetate tow. The length of the downstream filter segment 24 is approximately 10 mm.

[0412] 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 internal cavity that extends throughout from the upstream end to the downstream end of the downstream hollow tubular element 26. The internal cavity is substantially empty, and thus substantially unrestricted airflow along the internal cavity is possible. 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.

[0413] The aerosol generating article 10 includes a ventilation zone 36 provided along a 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 about 2 millimeters from the downstream end of the hollow tubular cooling element 22.

[0414] 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 aspects: The rod 12 of the aerosol generating base is shorter, and the hollow tubular cooling element 22 is longer. The length of the rod 12 of the aerosol generating base is approximately 25 mm. The length of the hollow tubular cooling element 22 is approximately 40 mm.

[0415] 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 aspects: The hollow tubular cooling element 22 is shorter, and the downstream hollow tubular element 27 is longer. The length of the hollow tubular cooling element 22 is approximately 25 mm. The length of the downstream hollow tubular element 27 is approximately 20 mm. Furthermore, 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.

[0416] The aerosol generating article 103 shown in Figure 3b is similar to the aerosol generating article 102 shown in Figure 3a, differing only in the following aspects. The downstream hollow tubular element 27 comprises two adjacent hollow tubular segments 271 and 272. The first hollow tubular segment 271 is located between the downstream filter segment 24 and the second first hollow tubular segment 272.

[0417] In Figure 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 internal cavity that extends entirely from the upstream end of the first hollow tubular segment 271 to the downstream end of the first hollow tubular segment 271. The internal cavity is substantially empty, and thus substantially unrestricted airflow along the internal cavity is possible. The first hollow tubular segment 271 can not substantially contribute 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 in the downstream hollow tubular element 27 for approximately 2 mm from the upstream end of the first hollow tubular segment 271.

[0418] 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 internal cavity that extends entirely from the upstream end to the downstream end of the second hollow tubular segment 272. The internal cavity is substantially empty, and thus allows for substantially unrestricted airflow along the internal 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.

[0419] The aerosol generating articles 104 and 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 and 105 further comprise an upstream section 16 located upstream of the rod 12 of the aerosol generating substrate. The distal ends 18 of articles 104 and 105 are defined by the upstream ends of the upstream section 16. The upstream section 16 comprises upstream elements 341 and 342 that abut against the upstream ends of the rod 12. The length of the upstream elements 341 and 342 is approximately 5 mm. In article 104 shown in Figure 4a, the upstream element 341 is provided in the form of a cylindrical plug made of cellulose acetate tow. In 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.

[0420] 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 against the downstream end of the rod 12. The cooling element 32 abuts against the downstream end of the hollow tubular support element 28, and the downstream filter segment 24 abuts against 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.

[0421] The length of the rod 12 of the aerosol generating substrate is approximately 25 mm.

[0422] 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 internal cavity that extends throughout from the upstream end to the downstream end of the hollow tubular support element 28. The internal cavity is substantially empty, and therefore substantially unrestricted airflow along the internal cavity is possible. The hollow tubular support element 28 can not substantially contribute 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.

[0423] The cooling element 32 is formed from a thin polylactic acid (PLA) material that has been crimped, pleated, assembled, or folded to create pathways. The length of the cooling element 32 is approximately 18 mm.

[0424] The downstream filter segment 24 is equipped with a cylindrical plug made of cellulose acetate tow. The length of the downstream filter segment 24 is approximately 7 mm.

[0425] The maximum outer diameter of the aerosol-generating item 20 is approximately 7.3 mm.

[0426] The aerosol generating article 201 shown in Figure 6 is similar to the aerosol generating article 20 shown in Figure 5, but differs in that it further comprises a hollow tubular cooling element 22 and the rod 12 of the aerosol generating base is shorter. The length of the rod 12 of the aerosol generating base is 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 is in contact with the cooling element 32 and the downstream filter segment 24.

[0427] 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 internal cavity that extends throughout the entire length from the upstream end to the downstream end of the hollow tubular cooling element 22. The internal cavity is substantially empty, and therefore allows for substantially unrestricted airflow along the internal cavity. The hollow tubular cooling element 22 can not substantially contribute 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).

[0428] The aerosol generating article 202 shown in Figure 7 is similar to the aerosol generating article 201 shown in Figure 6, differing only in that it further comprises a downstream hollow tubular element 27. The downstream hollow tubular element 27 abuts against 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 27. The downstream end 19 of article 202 is defined by the downstream end of the downstream hollow tubular element 27.

[0429] 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 that extends entirely from the upstream end to the downstream end of the downstream hollow tubular element 27. The internal cavity is substantially empty, and thus substantially unrestricted airflow along the internal cavity is possible. The downstream hollow tubular element 27 can not substantially contribute 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.

[0430] The aerosol generating article 30 shown in Figure 8 comprises an aerosol generating base rod 12 and a downstream section 14 located downstream of the aerosol generating base rod 12. Furthermore, the aerosol generating article 30 includes an upstream section 16 located upstream of the aerosol generating base rod 12. The distal end 18 of the article 30 is defined by the upstream end of the upstream section 16.

[0431] 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 against the downstream end of the rod 12. The downstream filter segment 24 abuts against the downstream end of the hollow tubular cooling element 22. Therefore, 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.

[0432] The length of the rod 12 of the aerosol generating substrate is approximately 25 mm.

[0433] 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 internal cavity that extends throughout the entire length from the upstream end to the downstream end of the hollow tubular cooling element 22. The internal cavity is substantially empty, and thus allows for substantially unrestricted airflow along the internal cavity. The hollow tubular cooling element 22 can not substantially contribute 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).

[0434] The downstream filter segment 24 is equipped with a cylindrical plug made of cellulose acetate tow. The length of the downstream filter segment 24 is approximately 7 mm.

[0435] The upstream section 16 comprises an upstream element 341 that abuts the upstream end of the rod 12. The upstream element 341 is provided in the form of a cylindrical plug made of cellulose acetate tow. The length of the upstream element 341 is approximately 5 mm.

[0436] The aerosol generating article 30 includes a ventilation zone 36 provided along a 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 about 2 millimeters from the downstream end of the hollow tubular cooling element 22.

[0437] 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 rod 12 of the aerosol generating substrate is approximately 12 mm, and the length of the hollow tubular cooling element 22 is approximately 45 mm.

[0438] The aerosol generating article 302 shown in Figure 10 is similar to the aerosol generating article 301 shown in Figure 8, but differs in that the rod 12 is shorter, the hollow tubular cooling element 22 is longer, and article 302 further comprises a downstream hollow tubular element 27. In Figure 10, the length of the rod 12 of the aerosol generating substrate is approximately 12 mm, and the length of the hollow tubular cooling element 22 is approximately 40 mm. Therefore, 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 article 302 is defined by the downstream end of the downstream hollow tubular element 27.

[0439] 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 that extends entirely from the upstream end to the downstream end of the downstream hollow tubular element 27. The internal cavity is substantially empty, and thus substantially unrestricted airflow along the internal cavity is possible. The downstream hollow tubular element 27 can not substantially contribute 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.

[0440] 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 about 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.

[0441] The aerosol-generating article 40 shown in Figure 12 comprises a rod 12 of an aerosol-generating substrate and a downstream section 14 located downstream of the rod 12 of the aerosol-generating substrate. Furthermore, the aerosol-generating article 40 comprises an upstream section 16 located upstream of the rod 12 of the aerosol-generating substrate. The distal end 18 of the article is defined by the upstream end of the upstream section 16.

[0442] 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 against the downstream end of the rod 12. The hollow tubular cooling element 22 abuts against the downstream end of the hollow tubular support element 28, and the downstream filter segment 24 abuts against 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.

[0443] The length of the rod 12 of the aerosol generating substrate is approximately 20 mm.

[0444] 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 internal cavity that extends throughout from the upstream end to the downstream end of the hollow tubular support element 28. The internal cavity is substantially empty, and thus substantially unrestricted airflow along the internal cavity is possible. The hollow tubular support element 28 can not substantially contribute 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.

[0445] 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 internal cavity that extends throughout the entire length from the upstream end to the downstream end of the hollow tubular cooling element 22. The internal cavity is substantially empty, and thus allows for substantially unrestricted airflow along the internal cavity. The hollow tubular cooling element 22 can not substantially contribute to the overall RTD of the aerosol generating article 40. The length of the hollow tubular cooling element 22 is about 8 mm. The wall thickness of the hollow tubular cooling element 22 is about 250 micrometers (μm).

[0446] The downstream filter segment 24 is equipped with a cylindrical plug made of cellulose acetate tow. The length of the downstream filter segment 24 is approximately 12 mm.

[0447] The upstream section 16 comprises an upstream element 341 that abuts the upstream end of the rod 12. The upstream element 341 is provided in the form of a cylindrical plug made of cellulose acetate tow. The length of the upstream element 341 is approximately 5 mm.

[0448] The aerosol generating article 40 includes a ventilation zone 36 provided along a 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 about 2 millimeters from the downstream end of the hollow tubular cooling element 22.

[0449] The aerosol generating article 40 comprises an elongated susceptor element 44 located within the rod 12 of the aerosol generating substrate. The susceptor element 44 is positioned substantially along the long axis within the rod 12, substantially parallel to the long axis of the rod 12. When the elongated susceptor element 44 is 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 while in a fluctuating electromagnetic field.

[0450] As shown in Figure 12, the susceptor element 44 is positioned centrally in the radial direction of the rod and extends effectively along the long axis of the rod 12. The susceptor element 44 extends along the entire length of the rod 12, from the upstream end to the downstream end. In practice, the susceptor element 44 has substantially the same length as the rod 12 of the aerosol generating substrate.

[0451] The susceptor element 44 is provided in any form 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 detaching. Furthermore, this ensures that consumers cannot accidentally come into contact with the heated susceptor element 44 after use.

[0452] 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 approximately 12 mm, and the length of the hollow tubular cooling element 22 is approximately 25 mm.

[0453] The aerosol generating article 402 shown in Figure 14 is similar to the aerosol generating article 40 shown in Figure 12, but differs in that the rod 12 is shorter, the hollow tubular cooling element 22 is longer, and article 402 further comprises a downstream hollow tubular element 27. In article 402 shown in Figure 14, the length of the rod 12 of the aerosol generating substrate is approximately 12 mm, and the length of the hollow tubular cooling element 22 is approximately 20 mm. Therefore, 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 article 402 is defined by the downstream end of the downstream hollow tubular element 27.

[0454] 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 that extends throughout from the upstream end to the downstream end of the downstream hollow tubular element 27. The internal cavity is substantially empty, and thus substantially unrestricted airflow along the internal cavity is possible. The downstream hollow tubular element 27 can not substantially contribute 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.

[0455] The aerosol generating article 403 shown in Figure 15 is similar to the aerosol generating article 402 shown in Figure 14, but differs in that a ventilation zone 36 is provided along the downstream hollow tubular element 27. The ventilation zone 36 is provided about 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.

[0456] Figure 16 illustrates an aerosol generation system 1 comprising an exemplary aerosol generator 50 and an aerosol generating article as shown in Figures 1 to 15 or described above.

[0457] Figure 16 illustrates the downstream mouth end portion of the aerosol generator 50, where a device cavity is defined and an aerosol generating article can be received. The aerosol generator 50 comprises a housing (or body) 4 extending between the mouth end 2 and a distal end (not shown). The housing 4 comprises a peripheral wall 6. The peripheral wall 6 defines a device cavity for receiving the 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 generator 1. The aerosol generating article 10 is configured to be received through the mouth end of the device cavity and to abut against the closed end of the device cavity.

[0458] The airflow channel 5 of the device is defined within the surrounding wall 6. The airflow channel 5 extends between the inlet 7 located at the mouth end of the aerosol generator 1 and the closed end of the device cavity. Air may also enter the aerosol generating substrate 12 through an opening (not shown) provided at the closed end of the device cavity, ensuring fluid communication between the airflow channel 5 and the aerosol generating substrate 12.

[0459] The aerosol generator 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 to control the supply of such power to the heater. The heater is configured to controllably heat the aerosol generating article when it is received into the device 1 and during use. Preferably, the heater is arranged to heat the aerosol generating substrate of the aerosol generating article from the outside for optimal aerosol generation. A ventilation zone for the aerosol generating article is arranged to be exposed when the aerosol generating article is received into the aerosol generator 1.

[0460] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers representing amounts, quantities, percentages, etc., should be understood in all cases as being modified by the term “approximately.” Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges within them, which may or may not be specifically listed herein. Thus, in this context, the number A is understood as A ± 10%. In this context, the number A may be considered to include a number that falls within the general standard error of the measurement of the characteristic that the number A modifies. In some cases used in the appended claims, the number A may deviate by the percentages listed above, provided that the amount of deviation of A does not substantially affect the basic and novel characteristics of the claimed invention. Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges within them, which may or may not be specifically listed herein.

Claims

1. Aerosol-generating article, A rod of an aerosol generating substrate, wherein the aerosol generating substrate contains tobacco material having a bulk density of less than 350 milligrams per cubic centimeter, Aerosol generating article comprising: a downstream section provided downstream of the rod of the aerosol generating substrate, the downstream section having a hollow tubular element that abuts the downstream end of the rod of the aerosol generating substrate and having a length of at least 40 millimeters.

2. The aerosol generating article according to claim 1, wherein the rod of the aerosol generating substrate has a length of at least 17 millimeters.

3. The aerosol-generating article according to claim 1 or 2, wherein the tobacco material has an average density of less than 300 milligrams per cubic centimeter.

4. The aerosol-generating article according to any one of claims 1 to 3, wherein the tobacco material has an average density of at least 100 milligrams per cubic centimeter.

5. The aerosol generating article according to any one of claims 1 to 4, wherein the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article is at least 0.2, preferably at least 0.

25.

6. The aerosol generating article according to any one of claims 1 to 5, wherein the rod of the aerosol generating substrate has a length of less than 30 millimeters.

7. The aerosol generating article according to any one of claims 1 to 6, wherein the length of the downstream section is at least 45 millimeters.

8. The aerosol generating article according to any one of claims 1 to 7, wherein the rod of the aerosol generating substrate has a length of at least 20 millimeters.

9. The aerosol generating article according to any one of claims 1 to 8, further comprising a ventilation zone located along the hollow tubular element of the downstream section.

10. The aerosol generating article according to any one of claims 1 to 9, wherein the wall thickness of the hollow tubular element in the downstream section is less than 0.5 millimeters.

11. The aerosol generating article according to any one of claims 1 to 10, wherein the ratio of the length of the hollow tubular element in the downstream section to the length of the rod of the aerosol generating substrate is at least 1.

5.

12. The aerosol generating article according to any one of claims 1 to 11, wherein the ratio of the length of the hollow tubular element in the downstream section to the total length of the aerosol generating article is at least 0.

5.

13. The aerosol generating article according to any one of claims 1 to 12, wherein the length of the hollow tubular element is at least 25 millimeters.

14. The aerosol generating article according to any one of claims 1 to 13, wherein the length of the hollow tubular element is at least 45 millimeters.

15. The aerosol generating article according to any one of claims 1 to 14, wherein the aerosol generating substrate includes shredded tobacco material.

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