Aerosol generating article having a ventilated cavity and upstream elements

Abstract

We provide aerosol-generating articles. [Solution] An aerosol generating article (10) for generating an inhalable aerosol when heated comprises an aerosol generating base rod (12), a downstream section (14) installed downstream of the aerosol generating base rod (12), the downstream section (14) including at least one hollow tubular element (20) that abuts the downstream end of the aerosol generating base rod (12), and an upstream of the aerosol generating base rod (12) and the aerosol generating base The device comprises an upstream element (42) that abuts the upstream end of a rod (12), the upstream end of which defines the upstream end of an aerosol generating article (10), and the upstream element (42) having a length of 3 mm to 7 mm, and a ventilation zone (30) located along a hollow tubular element (20), the distance between the ventilation zone (30) and the upstream end of the upstream element (20) being 26 mm to 33 mm.

Description

Technical Field

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

Background Art

[0002] Aerosol-generating 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-generating 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-generating article. The released compounds condense as they cool to form an aerosol.

[0003] Numerous prior art documents disclose aerosol-generating devices for consuming aerosol-generating articles. Such devices include, for example, electrically heated aerosol-generating devices in which an aerosol is generated by heat transfer from one or more electrical heater elements of the aerosol-generating device to the aerosol-generating substrate of the heated aerosol-generating article. For example, electrically heated aerosol-generating devices have been proposed that include an internal heater blade adapted to be inserted into the aerosol-generating substrate. The use of aerosol-generating articles in combination with an external heating system is also known. For example, WO2020 / 115151 describes the provision of one or more heating elements arranged around the perimeter of an aerosol-generating article when the aerosol-generating article is received within a cavity of an aerosol-generating device. Alternatively, an inductively heatable aerosol-generating article comprising an aerosol-generating substrate and a susceptor disposed within the aerosol-generating substrate has been proposed by WO2015 / 176898.

Summary of the Invention

[0004] Aerosol-generating articles in which the tobacco-containing substrate is heated rather than burned present several challenges not encountered in conventional smoking articles. First, 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-side 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 a novel aerosol-generating article that can consistently ensure satisfactory aerosol delivery to the consumer.

[0005] Secondly, there is a need for aerosol generating articles that are generally easy to use and have improved practicality. For example, it is desirable to provide an aerosol generating article that can be easily inserted into the heated cavity of an aerosol generating device and, at the same time, can be securely held within the heated cavity so as not to slip out during use.

[0006] Therefore, it would be desirable to provide a new and improved aerosol-generating article adapted to achieve at least one of the desirable results described above. Furthermore, it would be desirable to provide one such aerosol-generating article that can be manufactured efficiently and quickly, preferably has a satisfactory RTD, and exhibits small RTD variation between articles.

[0007] This disclosure relates to an aerosol generating article. The aerosol generating article may include a rod of an aerosol generating substrate. The aerosol generating article may include a hollow tubular element installed downstream of the rod of the aerosol generating substrate. The hollow tubular element may abut against the downstream end of the rod of the aerosol generating substrate. The aerosol generating article may include an upstream element installed upstream of the rod of the aerosol generating substrate. The upstream element may abut against the upstream end of the rod of the aerosol generating substrate. The upstream end of the upstream element may define the upstream end of the aerosol generating article. The upstream element may have a length of 3 mm to 7 mm. The aerosol generating article may include a ventilation zone. The ventilation zone may be installed along the hollow tubular element. The distance between the ventilation zone and the upstream end of the upstream element may be 26 mm to 33 mm.

[0008] Furthermore, this disclosure relates to an aerosol generating system comprising the aerosol generating article and aerosol generating device described above, wherein the aerosol generating device comprises a heating chamber for receiving the aerosol generating article and heating members arranged in or around the heating chamber.

[0009] The present invention provides an aerosol generating article comprising a rod of an aerosol generating substrate. The aerosol generating article further includes a hollow tubular element positioned downstream of the rod of the aerosol generating substrate and in contact with the downstream end of the rod of the aerosol generating substrate. Additionally, the aerosol generating article comprises an upstream element positioned upstream of the rod of the aerosol generating substrate and in contact with the upstream end of the rod of the aerosol generating substrate. The upstream end of the upstream element defines the upstream end of the aerosol generating article. The upstream element has a length of 3 mm to 7 mm. The aerosol generating article further comprises a ventilation zone positioned along the hollow tubular element. The distance between the ventilation zone and the upstream end of the upstream element is 26 mm to 33 mm.

[0010] Furthermore, according to the present invention, an aerosol generating system is provided which includes the aerosol generating article and aerosol generating device described above, the aerosol generating device comprising a heating chamber for receiving the aerosol generating article and heating members arranged in or around the heating chamber.

[0011] The aerosol generating article according to the present invention provides an improved configuration of elements immediately upstream and immediately downstream of the aerosol generating substrate rod, which have a direct influence on the arrangement of the aerosol generating substrate rod within the heating chamber of the aerosol generating device during use. The upstream element, provided upstream of the aerosol generating substrate rod and in contact with it, has a predetermined length that provides precise positioning of the aerosol generating substrate within the heating chamber.

[0012] In addition, in the aerosol generating article according to the present invention, the length of the upstream element and the arrangement of the ventilation zone relative to the upstream end of the upstream element are selected to provide rapid cooling of species flowing along a cavity internally defined by a hollow tubular element.

[0013] The intense cooling caused by the intrusion of ambient air drawn into a cavity internally defined by a hollow tubular element through a ventilation zone is understood to accelerate the condensation of aerosol-forming (e.g., glycerin) droplets, where volatile nicotine and organic acids released during heating of the tobacco substrate accumulate and combine to form nicotine salts. With this in mind, the placement of the ventilation zone relative to the upstream end of the upstream element was chosen in terms of reducing the flight time of volatile nicotine before the vaporized nicotine reaches the aerosol-forming droplets, and creating time and space for nicotine accumulation and nicotine salt formation within the generated aerosol-forming droplets before the aerosol stream reaches the consumer's mouth.

[0014] When the shape (volume, length), density, and aerosol-forming content of the substrate are selected to provide consumers with specific desired aerosol delivery and RTD during use, the length of the upstream element may be adjusted to each claimed range so that the positioning of the ventilation zone relative to the upstream end of the upstream element is also within each claimed range when designing an article for use with a specific heating device having predetermined characteristics (e.g., internal or external heating, length and diameter of the heating chamber, etc.).

[0015] Therefore, the selected length of the upstream element and the distance between the ventilation zone and the upstream end of the upstream element in the article according to the present invention provide a combination that optimizes the arrangement of the substrate and the ventilation zone within the aerosol generator to improve aerosol generation and delivery to the consumer.

[0016] In a preferred embodiment, the distance between the ventilation zone and the upstream end of the upstream element is 27 mm to 31 mm.

[0017] In the aerosol generating article according to the present invention, the rod of the aerosol generating substrate preferably has a length of 8 mm to 16 mm, more preferably 10 mm to 14 mm.

[0018] In the aerosol generating article according to the present invention, a hollow tubular element positioned downstream of the rod of the aerosol generating substrate has a small influence on the overall RTD of the aerosol generating article, unless it is completely negligible. On the other hand, the RTD of the upstream element and the RTD of the rod of the aerosol generating article have a more significant influence proportional to the overall RTD of the aerosol generating article. Once the length and properties of the upstream element are defined, the contribution of the upstream element to the overall RTD of the aerosol generating article is generally easy to control, as the RTD of the upstream element in different aerosol generating articles having the same design tends to be highly consistent. In contrast, controlling the RTD of the rod of the aerosol generating substrate can be more difficult, especially when the aerosol generating substrate contains natural materials such as tobacco material. Variations in the RTD of the rod of the aerosol generating substrate can occur due to changes in the type of tobacco material, as well as the arrangement of the tobacco material within the rod, particularly when the tobacco material is provided in the form of randomly arranged fragments.

[0019] By adjusting the length of the rods of the aerosol generating substrate within the range described above, and by controlling the density of the aerosol generating substrate itself, the inventors have found that it is easier to control the overall RTD of the aerosol generating article more effectively and consistently. Furthermore, since the length of the rods is also predetermined, it is easy to ensure the desired arrangement of the ventilation zones relative to the substrate and heating device during use.

[0020] As described above, 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 installed downstream of the aerosol generating substrate. One or more elements downstream of the rod of the aerosol generating article form the downstream section of the aerosol generating substrate. Furthermore, the aerosol generating article according to the present invention comprises elements installed upstream of the aerosol generating substrate. The elements upstream of the rod of the aerosol generating substrate define the upstream section of the aerosol generating article.

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

[0022] The rod of the aerosol generation substrate preferably has a length of at least about 8 millimeters. The rod of the aerosol generation substrate preferably has a length of at least about 9 millimeters. More preferably, the rod of the aerosol generation substrate has a length of at least about 10 millimeters.

[0023] For example, the rod of the aerosol generation substrate preferably has a length of about 8 millimeters to about 16 millimeters, or about 9 millimeters to about 15 millimeters, or about 10 millimeters to about 14 millimeters. In a particularly preferred embodiment, the rod of the aerosol generation substrate has a length of about 12 millimeters.

[0024] The ratio of the length of the rod of the aerosol generation substrate to the total length of the aerosol generation article is at least about 0.15, more preferably at least about 0.2, and most preferably at least about 0.22.

[0025] Preferably, the ratio of the length of the rod of the aerosol generation substrate to the total length of the aerosol generation article is 0.35 or less, more preferably about 0.33 or less, and even more preferably about 0.3 or less.

[0026] In a particularly preferred embodiment of the present invention, the ratio of the length of the rod of the aerosol generation substrate to the total length of the aerosol generation article is about 0.25.

[0027] The rod of the aerosol generation substrate preferably has an outer diameter substantially equal to the outer diameter of the aerosol generation article.

[0028] The "outer diameter of the rod of the aerosol generation substrate" can be calculated as the average of a plurality of measured values of the diameter of the rod of the aerosol generation substrate taken at different positions along the length of the rod of the aerosol generation substrate.

[0029] The rod of the aerosol generating substrate preferably has an outer diameter of at least about 5 millimeters. More preferably, the rod of the aerosol generating substrate has an outer diameter of at least about 6 millimeters. Even more preferably, the rod of the aerosol generating substrate has an outer diameter of at least about 7 millimeters.

[0030] The rod of the aerosol generating substrate preferably has an outer diameter of about 12 millimeters or less. More preferably, the rod of the aerosol generating substrate has an outer diameter of about 10 millimeters or less. Even more preferably, the rod of the aerosol generating substrate has an outer diameter of about 8 millimeters or less.

[0031] Generally, it has been observed that the smaller the diameter of the rod of the aerosol generating substrate, the lower the temperature required to raise the core temperature of the rod of the aerosol generating substrate so that a sufficient amount of volatile species is released from the aerosol generating substrate to form the desired amount of aerosol. At the same time, without intending to be bound by theory, it is understood that the smaller the diameter of the rod of the aerosol generating substrate, the faster the heat supplied to the aerosol generating article can penetrate the total volume of the aerosol forming 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 forming substrate becomes unfavorable as the amount of available aerosol forming substrate decreases.

[0032] The diameters of the aerosol-generating substrate rods that fall within the range described herein are 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 periphery of the aerosol-generating article. Under such operating conditions, it has been observed that less thermal energy is required to achieve sufficiently high temperatures in the core of the aerosol-generating substrate rod, and generally in the core of the article. Thus, when operating at lower temperatures, the desired target temperature in the core of the aerosol-generating article can be achieved within a desirablely reduced time frame and with less energy consumption.

[0033] In some embodiments, the rod of the aerosol generating substrate has an outer diameter of about 5 mm to about 12 mm, preferably about 6 mm to about 12 mm, and more preferably about 7 mm to about 12 mm. In other embodiments, the rod of the aerosol generating substrate has an outer diameter of about 5 mm to about 12 mm, preferably about 6 mm to about 10 mm, and more preferably about 7 mm to about 10 mm. In further embodiments, the rod of the aerosol generating substrate has an outer diameter of about 5 mm to about 8 mm, preferably about 6 mm to about 8 mm, and more preferably about 7 mm to about 8 mm.

[0034] In a particularly preferred embodiment, the rod of the aerosol generating substrate has an outer diameter of less than about 7.5 millimeters. As an example, the rod of the aerosol generating substrate may have an outer diameter of about 7.2 millimeters.

[0035] The ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article may be at least about 0.10. Preferably, the ratio is at least about 0.15. More preferably, the ratio is about 0.20. Even more preferably, the ratio is at least about 0.25.

[0036] Generally, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article may be about 0.60 or less. Preferably, the ratio is about 0.50 or less. More preferably, the ratio is about 0.45 or less. Even more preferably, the ratio is about 0.40 or less. In a particularly preferred embodiment, the ratio is about 0.35 or less, and most preferably about 0.30 or less.

[0037] In some embodiments, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article is preferably about 0.10 to about 0.45, more preferably about 0.15 to about 0.45, more preferably about 0.20 to about 0.45, and even more preferably about 0.25 to about 0.45. In other embodiments, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article is preferably about 0.10 to about 0.40, more preferably about 0.15 to about 0.40, more preferably about 0.20 to about 0.40, and even more preferably about 0.25 to about 0.40. In further embodiments, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article is about 0.10 to about 0.35, preferably about 0.15 to about 0.35, more preferably about 0.20 to about 0.35, and even more preferably about 0.25 to about 0.35. In further embodiments, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article is about 0.10 to about 0.30, preferably about 0.15 to about 0.30, more preferably about 0.20 to about 0.30, and even more preferably about 0.25 to about 0.30.

[0038] 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.

[0039] In the aerosol generating article according to the present invention, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article may be about 0.60 or less. Preferably, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article may be about 0.50 or less. More preferably, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article may be about 0.40 or less. Even more preferably, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article may be about 0.30 or less.

[0040] In the aerosol generating article according to the present invention, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article may be at least about 0.10. Preferably, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article may be at least about 0.15. More preferably, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article may be at least about 0.20. In a particularly preferred embodiment, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article may be at least about 0.25.

[0041] In some embodiments, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article is about 0.10 to about 0.60, preferably about 0.15 to about 0.60, more preferably about 0.20 to about 0.60, and even more preferably about 0.25 to about 0.60. In other embodiments, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article substrate is about 0.10 to about 0.50, preferably about 0.15 to about 0.50, more preferably about 0.20 to about 0.50, and even more preferably about 0.25 to about 0.50. In further embodiments, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article is about 0.10 to about 0.40, preferably about 0.15 to about 0.40, more preferably about 0.20 to about 0.40, and even more preferably about 0.25 to about 0.40. As an example, the ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article may be about 0.25 to about 0.30, preferably about 0.27.

[0042] Preferably, the density of the aerosol generating substrate is at least about 150 milligrams per cubic centimeter. More preferably, the density of the aerosol generating substrate is at least about 175 mg per cubic centimeter. More preferably, the density of the aerosol generating substrate is at least about 200 mg per cubic centimeter. Even more preferably, the density of the aerosol generating substrate is at least about 250 mg per cubic centimeter.

[0043] Preferably, the density of the aerosol generating substrate is about 500 mg or less per cubic centimeter. More preferably, the density of the aerosol generating substrate is about 450 mg or less per cubic centimeter. More preferably, the density of the aerosol generating substrate is about 400 mg or less per cubic centimeter. Even more preferably, the density of the aerosol generating substrate is about 350 mg or less per cubic centimeter.

[0044] For example, the density of the aerosol generating substrate is about 150 mg to about 500 mg per cubic centimeter, preferably about 175 mg to about 450 mg per cubic centimeter, more preferably about 200 mg to about 400 mg per cubic centimeter, and even more preferably about 250 mg to about 350 mg per cubic centimeter. In a particularly preferred embodiment, the density of the aerosol generating substrate is about 300 mg per cubic centimeter.

[0045] In certain preferred embodiments, the rod of the aerosol generating substrate comprises shredded tobacco material, for example, tobacco cut filler, and has a density of about 150 mg to about 500 mg per cubic centimeter, preferably about 175 mg to about 450 mg per cubic centimeter, more preferably about 200 mg to about 400 mg per cubic centimeter, more preferably about 250 mg to about 350 mg per cubic centimeter, and most preferably about 300 mg per cubic centimeter.

[0046] The RTD of the aerosol generating substrate rod is preferably about 10 mmH2O or less. More preferably, the RTD of the aerosol generating substrate rod is about 9 mmH2O or less. Even more preferably, the RTD of the aerosol generating substrate rod is about 8 mmH2O or less.

[0047] The RTD of the aerosol generating substrate rod is preferably at least about 4 mmH2O. More preferably, the RTD of the aerosol generating substrate rod is at least about 5 mmH2O. Even more preferably, the RTD of the aerosol generating substrate rod is at least about 6 mmH2O.

[0048] In some embodiments, the RTD of the aerosol generating substrate rod is about 4 mmH2O to about 10 mmH2O, preferably about 5 mmH2O to about 10 mmH2O, and more preferably about 6 mmH2O to about 25 mmH2O. In other embodiments, the RTD of the aerosol generating substrate rod is about 4 mmH2O to about 20 mmH2O, preferably about 5 mmH2O to about 18 mmH2O, and more preferably about 6 mmH2O to about 16 mmH2O. In further embodiments, the RTD of the aerosol generating substrate rod is about 4 mmH2O to about 15 mmH2O, preferably about 5 mmH2O to about 14 mmH2O, and more preferably about 6 mmH2O to about 12 mmH2O.

[0049] 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, 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 dodecanediol and dimethyl tetradecanediol), and combinations thereof.

[0050] The aerosol-forming body preferably contains one or more of glycerin and propylene glycol. The aerosol-forming body may consist of glycerin or propylene glycol, or a combination of glycerin and propylene glycol.

[0051] Preferably, the aerosol generating substrate contains at least 5 weight percent of aerosol forming material on a dry weight basis of the aerosol generating substrate, more preferably 10 to 22 weight percent on a dry weight basis of the cut aerosol generating substrate, more preferably the amount of aerosol forming material is 12 to 19 weight percent on a dry weight basis of the aerosol generating substrate, and most preferably, for example, the amount of aerosol forming material is 13 to 16 weight percent on a dry weight basis of the aerosol generating substrate.

[0052] 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. Preferred homogenized tobacco materials for use in the present invention are described below.

[0053] In the context of this specification, the term “cut filler” is used specifically to describe a blend of chopped plant materials, such as tobacco plant materials, which include one or more of the following: leaf blades, processed stems and veins, and homogenized plant materials.

[0054] Cut filler may also include other cut pieces, filler tobacco, or casing.

[0055] Preferably, the cut filler contains at least 25 percent of plant leaf blades, more preferably at least 50 percent of plant leaf blades, even more preferably at least 75 percent of plant leaf blades, and most preferably at least 90 percent of plant leaf blades. 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 that, upon application of heat, have the ability to release a substance which can subsequently form an aerosol.

[0056] The tobacco plant material preferably includes 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.

[0057] 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 fully cured tobacco from other African countries. 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. According to the present 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.

[0058] 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 may be air-dried and fermented. From a sensory perspective, dark tobacco is a type of tobacco that, after drying, has a smoky, dark cigar-like feel. 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 at most about 0.5 percent on a dry weight basis of the leaves.

[0059] Aromatic tobacco is tobacco that often has small, light-colored leaves. Throughout this specification, the term “aromatic tobacco” is used for 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 tobacco include Greek Orient, Orient Turkey, semi-orient tobaccos that have been heat-dried, US Burley such as Perique, Rustica, US Burley, or Maryland. Filler tobacco is not a specific tobacco type but includes tobacco types that are used in blends and are primarily used to complement other tobacco types that 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 heat-dried stems of the lower petioles of Brazilian hot-air-dried petioles.

[0060] 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, the cutting width may affect the overall density of the aerosol generating substrate.

[0061] Since the strand length depends on the overall size of the object from which the strand is cut, the strand length of 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 before being arranged to form a rod of aerosol generating substrate. Obviously, if the strands are placed in the rod of aerosol generating substrate in a longitudinal extension portion where the longitudinal extension portion of the section 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 strands extend along the entire length of the rod of aerosol generating substrate. This prevents the strands from easily coming off the rod of aerosol generating substrate.

[0062] 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. In addition, in light of the aforementioned constraints on diameter and size, this makes it possible to balance the density of the aerosol-generating substrate rod between energy intake, extraction resistance, and fluid passages within the aerosol-generating substrate rod containing plant material.

[0063] Preferably, the cut filler is immersed in an aerosol-forming material. Immersion of the cut filler can be carried out by spraying or other suitable application methods. The aerosol-forming material may be applied to the blend during the preparation of the cut filler. For example, the aerosol-forming material may be applied directly to the blend in the conditioning casing cylinder (DCCC). Conventional machinery can be used to apply the aerosol-forming material to the cut filler. The aerosol-forming material can be any suitable known compound or mixture of compounds that promotes the formation of a dense and stable aerosol when used. The aerosol-forming material may promote the aerosol being substantially resistant to thermal decomposition at the temperatures typically applied during use of the aerosol-generating article. Suitable aerosol-forming materials 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.

[0064] The aerosol-forming body preferably contains one or more of glycerin and propylene glycol. The aerosol-forming body may consist of glycerin or propylene glycol, or a combination of glycerin and propylene glycol.

[0065] The amount of aerosol-forming material is preferably at least 5% by weight on a dry weight basis, and 10% to 22% by weight on a dry weight basis of the cut filler, and more preferably 12% to 19% by weight on a dry weight basis of the cut filler, for example, the amount of aerosol-forming material is 13% to 16% 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 to surrounding cut filler particles and surrounding surfaces (e.g., the inner surface of the wrapper surrounding the cut filler), thus helping to hold the cut filler in place within the article.

[0066] In some embodiments, the amount of aerosol-forming material has a target value of approximately 13 weight percent on a dry weight basis of the cut filler. The most efficient amount of aerosol-forming material also depends on the cut filler, and whether or not the cut filler contains plant leaf blades or homogenized plant material. For example, among other factors, the type of cut filler determines to what extent the aerosol-forming material can promote the release of material from the cut filler.

[0067] For these reasons, a rod of aerosol generating substrate containing the aforementioned cut filler can efficiently generate a sufficient amount of aerosol at relatively low temperatures. A temperature of 150°C to 200°C in the heating chamber may be sufficient for one such cut filler to generate a sufficient amount of aerosol, whereas aerosol generators using tobacco cast leaf sheets typically use a temperature of around 250°C.

[0068] A further advantage of the present invention related to operating at lower temperatures is the reduced need for aerosol cooling. Since generally lower temperatures are used, a simpler cooling mechanism may suffice. This, in turn, allows for the use of simpler and less complex structures for aerosol-generating articles.

[0069] In other preferred embodiments, the aerosol-generating substrate includes homogenized plant material, preferably homogenized tobacco material.

[0070] 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 an aerosol-generating substrate of the present invention may be formed by aggregating plant material and, optionally, tobacco material particles obtained by grinding, crushing, or pulverizing one or more of the leaf blades and stalks of tobacco leaves. The homogenized plant material may be produced by casting, extrusion, papermaking processes, or any other suitable process known in the art.

[0071] Homogenized plant material can be provided in any preferred form.

[0072] 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.

[0073] The homogenized plant material may be in the form of multiple pellets or granules.

[0074] Homogenized plant material may be in the form of multiple strands, strips, or fragments. As used herein, the term “strand” refers to 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 shredding, or by other means, such as by extrusion.

[0075] In some embodiments, strands may be formed in situ within the aerosol-generating substrate as a result of splitting or cracking 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 splitting of a sheet of homogenized plant material during the manufacture of the aerosol-generating substrate as described above.

[0076] If the homogenized plant material is in the form of one or more sheets, the sheets can be manufactured by a casting process, as described above. Alternatively, sheets of homogenized plant material can be manufactured by a papermaking process.

[0077] The one or more sheets described herein may each individually have a thickness of 100 to 600 micrometers, preferably 150 to 300 micrometers, and most preferably 200 to 250 micrometers. Individual thicknesses refer to the thickness of individual sheets, 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.

[0078] Each of the sheets described herein may individually have a basis weight ranging from about 100 grams per square meter to about 600 grams per square meter.

[0079] Each of the one or more sheets described herein may individually have a density of about 0.3 grams to about 1.3 grams per cubic centimeter, preferably about 0.7 grams to about 1.0 gram per cubic centimeter.

[0080] 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.

[0081] One or more sheets of homogenized plant material can be assembled transversely to their longitudinal axis and surrounded by a wrapper to form a continuous rod or plug.

[0082] One or more sheets of homogenized plant material may be advantageously crimped or similarly treated. As used herein, the term “crimped” means a sheet having multiple substantially parallel ridges or wavy patterns. One or more sheets of homogenized plant material may be embossed, debossed, perforated, or otherwise deformed to provide tactile properties on one or both sides of the sheet.

[0083] Preferably, each sheet 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 sheet 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.

[0084] Alternatively, 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 can 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.

[0085] 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 about 90 weight percent of plant particles on a dry weight basis, more preferably about 80 weight percent of plant particles, more preferably about 70 weight percent of plant particles, more preferably about 60 weight percent of plant particles, and more preferably about 50 weight percent of plant particles.

[0086] For example, the homogenized plant material may contain, on a dry weight basis, approximately 2.5 to 95 percent by weight of plant particles, or approximately 5 to 90 percent by weight of plant particles, or approximately 10 to 80 percent by weight of plant particles, or approximately 15 to 70 percent by weight of plant particles, or approximately 20 to 60 percent by weight of plant particles, or approximately 30 to 50 percent by weight of plant particles.

[0087] In certain embodiments of the present invention, the homogenized plant material is a homogenized tobacco material containing tobacco particles. A sheet of the homogenized tobacco material used in such embodiments of the present invention may have a tobacco content of at least about 40 weight percent on a dry weight basis, more preferably at at least about 50 weight percent on a dry weight basis, more preferably at at least about 70 weight percent on a dry weight basis, and most preferably at at least about 90 weight percent on a dry weight basis.

[0088] In relation to the present invention, the term "tobacco particles" refers to particles of any plant material of the genus Nicotiana. The term "tobacco particles" includes crushed or powdered tobacco leaf blades, 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 blades. 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.

[0089] 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 homogenized plant material are known in the art and include, but are not limited to, polyhydric alcohols (such as triethylene glycol, propylene glycol, 1,3-butanediol, and glycerol), esters of polyhydric alcohols (such as glycerol mono-, di-, or triacetate), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dodecanedioic acid and dimethyl tetradecanedioate).

[0090] Homogenized plant material may contain aerosol-forming compounds of approximately 5% to 30% by dry weight, such as approximately 10% to 25% by dry weight, or approximately 15% to 20% by dry weight. The aerosol-forming compounds can act as wetting agents in the homogenized plant material.

[0091] As described 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.

[0092] The paper wrapper may have a basis weight of at least 15 gsm, 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.

[0093] 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 advantageously prevents combustion of the aerosol-generating substrate when the aerosol-generating substrate is to be ignited rather than heated in the intended manner.

[0094] 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 a preferred embodiment, the paper layer of the co-laminated sheet may have a basis weight of 45 gsm.

[0095] 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 also have a thickness of 80 micrometers or less, preferably 75 micrometers or less, and more preferably 70 micrometers or less.

[0096] 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 a preferred embodiment, the paper layer of the co-laminated sheet may have a thickness of 65 microns.

[0097] 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 a preferred embodiment, the metal layer of the co-laminated sheet may have a basis weight of 17 gsm.

[0098] 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.

[0099] The metal layer 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 a preferred embodiment, the metal layer of the co-laminated sheet may have a thickness of 6 microns.

[0100] The wrapper surrounding the rod of the aerosol generating substrate may be a paper wrapper containing PVOH (polyvinyl alcohol) or silicon. The addition of PVOH (polyvinyl alcohol) or silicon may improve the grease barrier properties of the wrapper.

[0101] PVOH or silicon is applied to the paper layer as a surface coating, such as by being disposed on the outer surface of the paper layer of the wrapper surrounding the rod of the aerosol generating substrate. PVOH or silicon may be disposed on the outer surface of the paper layer of the wrapper and may form a layer. PVOH or silicon may be disposed on the inner surface of the paper layer of the wrapper. PVOH or silicon may be disposed on the inner surface of the paper layer of the aerosol generating article and may form a layer. PVOH or silicon may be disposed on both the inner and outer surfaces of the paper layer of the wrapper. PVOH or silicon may be disposed on both the inner and outer surfaces of the paper layer of the wrapper and may form a layer.

[0102] The paper wrapper containing PVOH or silicon may have a basis weight of at least 20 gsm, preferably at least 25 gsm, and more preferably at least 30 gsm. The paper wrapper containing PVOH or silicon may have a basis weight of 50 gsm or less, 45 gsm or less, and more preferably 40 gsm or less. The paper wrapper containing PVOH or silicon may have a basis weight of 20 gsm to 50 gsm, preferably 25 gsm to 45 gsm, and more preferably 30 gsm to 40 gsm. In a particularly preferred embodiment, the paper wrapper containing PVOH or silicon may have a basis weight of about 35 gsm.

[0103] A paper wrapper containing PVOH or silicon 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 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 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 may have a thickness of 37 micrometers.

[0104] 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, the flame-retardant compounds may be activated by the presence of an ignition source and are adapted to prevent or delay further development of ignition by various different physical and chemical mechanisms.

[0105] A flame retardant composition typically further comprises one or more non-flammable compounds, such as solvents, excipients, and fillers, which do not actively contribute to providing flammability protection to the carrier substrate but are used to facilitate the application of one or more flame retardant compounds onto or into the wrapper, or both. Some of the non-flammable compounds in a flame retardant composition, such as solvents, are volatile and may evaporate from the wrapper upon drying after the flame retardant composition has been applied onto or into the wrapping substrate, or both. Thus, although such non-flammable compounds form part of the formulation of the flame retardant composition, these compounds may no longer be present or may only be detectable in trace amounts in the wrapper of the aerosol-generating article.

[0106] Numerous suitable flame retardants will be well known to those skilled in the art. In particular, several flame retardants and formulations suitable for treating cellulose materials are known and disclosed and may be used in the manufacture of wrappers for aerosol-generating articles according to the present invention.

[0107] For example, the flame retardant composition comprises 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, where at least one mono, di, and / or tricarboxylic acid and hydroxide or salt form a carboxylate and at least one polyphosphate, and pyrophosphate and / or phosphoric acid and 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.

[0108] 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 to the treated portion of the wrapper. This means that the flame retardant composition is applied to the corresponding portion of the wrapping substrate, 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 about 10 percent of the outer surface area of ​​the rods of the aerosol-generating substrate surrounded by the wrapper, preferably at least about 20 percent, more preferably at least about 40 percent, and even more preferably at least about 60 percent. Most preferably, the treated portion of the wrapper extends over at least about 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 about 90 or 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.

[0109] 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.

[0110] 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 more preferably 40 micrometers or less. In some embodiments, the wrapper containing the flame retardant composition may have a thickness of 37 micrometers.

[0111] The aerosol-generating article according to this disclosure comprises an upstream section located upstream of the rod of the aerosol-generating substrate. Preferably, the upstream section is located immediately upstream of the rod of the aerosol-generating substrate. Preferably, the upstream section extends between the upstream end of the aerosol-generating article and the rod of the aerosol-generating substrate.

[0112] The upstream section includes an upstream element located upstream of the rod of the aerosol generating substrate. Preferred upstream elements are described in this disclosure.

[0113] 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, in turn, helps to fix the shape and position of the susceptor element.

[0114] Furthermore, the presence of upstream elements can be advantageous, for example, when the substrate contains particulate plant material, as it helps prevent any loss of the substrate.

[0115] If the aerosol generating substrate contains shredded tobacco such as tobacco cut filler, the upstream section or its elements may further help prevent the loss of loose tobacco particles from the upstream end of the article.

[0116] The upstream section, or its upstream element, can also provide some degree of additional protection to the aerosol-generating substrate during storage, by covering at least some extent the upstream end of the aerosol-generating substrate, otherwise it may be exposed.

[0117] For aerosol-generating articles intended to be inserted into a cavity within an aerosol generator, such that the aerosol-generating substrate can be heated from the outside within the cavity, upstream section, or upstream element, it is advantageous that the insertion of the upstream end of the article into the cavity can be facilitated. Inclusion of an upstream element can further protect 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.

[0118] 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 the brand, flavor, content, or details of the aerosol generator in which the article is intended to be used.

[0119] The upstream element may be a porous plug element. Preferably, the upstream element has a porosity of at least about 50 percent in the longitudinal direction of the aerosol-generating article. More preferably, the upstream element has a porosity of about 50 percent to about 90 percent in the longitudinal direction. The longitudinal porosity of the upstream element 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.

[0120] 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 entire cross-section of the upstream element.

[0121] 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) without substantially affecting the filtration provided by the other parts of the article.

[0122] 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 a suitable ventilation means provided within the wrapper.

[0123] 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. For such articles, it is desirable to provide the article with the lowest possible RTD so that the majority of the consumer's RTD experience is provided by the aerosol generator rather than the article itself.

[0124] The RTD of the upstream element is preferably about 10 mmH2O or less. More preferably, the RTD of the upstream element is about 5 mmH2O or less. Even more preferably, the RTD of the upstream element is about 2.5 mmH2O or less. Even more preferably, the RTD of the upstream element is about 2 mmH2O or less.

[0125] The RTD of the upstream element may be at least 0.1 milliH2O, or at least about 0.25 milliH2O, or at least about 0.5 milliH2O.

[0126] In some embodiments, the RTD of the upstream element is about 0.1 mmH2O to about 10 mmH2O, preferably about 0.25 mmH2O to about 10 mmH2O, and preferably about 0.5 mmH2O to about 10 mmH2O. In other embodiments, the RTD of the upstream element is about 0.1 mmH2O to about 5 mmH2O, preferably about 0.25 mmH2O to about 5 mmH2O, and preferably about 0.5 mmH2O to about 5 mmH2O. In further embodiments, the RTD of the upstream element is about 0.1 mmH2O to about 2.5 mmH2O, preferably about 0.25 mmH2O to about 2.5 mmH2O, and more preferably about 0.5 mmH2O to about 2.5 mmH2O. In further embodiments, the RTD of the upstream element is about 0.1 mmH2O to about 2 mmH2O, preferably about 0.25 mmH2O to about 2 mmH2O, and more preferably about 0.5 mmH2O to about 2 mmH2O. In particularly preferred embodiments, the RTD of the upstream element is about 1 mmH2O.

[0127] Preferably, the upstream element has an RTD of less than about 2 mm of H2O per millimeter of length, more preferably less than about 1.5 mm of H2O per millimeter of length, more preferably less than about 1 mm of H2O per millimeter of length, more preferably less than about 0.5 mm of H2O per millimeter of length, more preferably less than about 0.3 mm of H2O per millimeter of length, and more preferably less than about 0.2 mm of H2O per millimeter of length.

[0128] Preferably, the composite RTD of the upstream section or its upstream element, and the rod of the aerosol generating substrate are less than about 15 mmH2O, more preferably less than about 12 mmH2O, and more preferably less than about 10 mmH2O.

[0129] In a particularly preferred embodiment, the upstream element is formed from a hollow tubular segment defining a longitudinal cavity that provides an unlimited 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-discharge (RTD) and filtration characteristics of the article.

[0130] Preferably, the diameter of the longitudinal cavity of the hollow tubular segment forming the upstream element is at least about 4 mm, more preferably at least about 4.5 mm, more preferably at least about 5 mm, and more preferably at least about 5.5 mm. Preferably, the diameter of the longitudinal cavity is maximized to minimize the RTD of the upstream section or its upstream element. The inner diameter of the upstream element may be about 5.1 mm.

[0131] Preferably, the wall thickness of the hollow tubular segment is less than about 2 mm, more preferably less than about 1.5 mm, and more preferably less than about 1.25 mm. The wall thickness of the hollow tubular segment defining the upstream element may be about 1 mm.

[0132] 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 one of the other components of the aerosol generating article, such as a mouthpiece, cooling element, or support element. Suitable materials for forming the upstream elements include filter materials, ceramics, polymer materials, cellulose acetate, cardboard, zeolite, or aerosol generating substrates. The upstream elements may include a cellulose acetate plug. The upstream elements may include a hollow acetate tube or a cardboard tube.

[0133] The upstream element is preferably formed from a heat-resistant material. For example, the upstream element is preferably formed from a material that can withstand 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.

[0134] Preferably, the upstream section or its upstream element 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 about 6 mm to about 8 mm, more preferably about 7 mm to about 7.5 mm. Preferably, the upstream section or its upstream element has an outer diameter of about 7.1 mm.

[0135] Preferably, the upstream section or upstream element has a length of about 2 mm to about 8 mm, more preferably about 3 mm to about 7 mm, and more preferably about 4 mm to about 6 mm. In a particularly preferred embodiment, the upstream section or upstream element has a length of about 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 can be increased to maintain the same overall length of the article.

[0136] In addition, the length of the upstream section or its upstream element may be used to control the position of the aerosol-generating article within the cavity of the aerosol generator for articles intended to be externally heated. This can advantageously ensure that the position of the aerosol-generating substrate within the cavity can be optimized for heating, and that the position of any ventilation can also be optimized.

[0137] The upstream section is preferably surrounded by a wrapper, such as a plug wrap. The wrapper surrounding the upstream element is preferably a rigid plug wrap, for example, a plug wrap having a basis weight of at least about 80 grams / square meter (gsm), or at least about 100 gsm, or at least about 110 gsm. This provides structural rigidity to the upstream section.

[0138] 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.

[0139] 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 include one or more elements, each of which will be described in more detail in this disclosure.

[0140] The length of the downstream section may be at least approximately 20 mm. The length of the downstream section may be at least approximately 24 mm. The length of the downstream section may be at least approximately 26 mm.

[0141] The length of the downstream section may be approximately 36 mm or less (in other words, not exceeding it). The length of the downstream section may be approximately 32 mm or less. The length of the downstream section may be approximately 30 mm or less.

[0142] The length of the downstream section may be approximately 20mm to 36mm. The length of the downstream section may be approximately 24mm to 32mm. The length of the downstream section may be approximately 26mm to 30mm.

[0143] Preferably, the downstream section includes a hollow tubular element. Preferably, the downstream section includes a mouthpiece element. In a preferred embodiment of the present invention, the downstream section includes or consists of a hollow tubular element and a mouthpiece element, the hollow tubular element being located between the rod of the aerosol generating substrate and the mouthpiece element.

[0144] In embodiments where the downstream section includes hollow tubular elements and mouthpiece elements, the total length or overall length of the hollow tubular elements and mouthpiece elements may be at least about 20 mm. In other words, the sum of the lengths of the hollow tubular elements and mouthpiece elements may be at least about 20 mm. The total length of the hollow tubular elements and mouthpiece elements may be at least about 24 mm. The total length of the hollow tubular elements and mouthpiece elements may be at least about 26 mm.

[0145] The total length of the hollow tubular element and mouthpiece element may be approximately 36 mm or less. The total length of the hollow tubular element and mouthpiece element may be approximately 32 mm or less. The total length of the hollow tubular element and mouthpiece element may be approximately 30 mm or less.

[0146] The total length of the hollow tubular element and mouthpiece element may be approximately 20 mm to 36 mm. The total length of the hollow tubular element and mouthpiece element may be approximately 24 mm to 32 mm. The total length of the hollow tubular element and mouthpiece element may be approximately 26 mm to 30 mm.

[0147] Preferably, the total length of the hollow tubular element and the mouthpiece element may be about 28 mm.

[0148] In an embodiment where the downstream section consists of a hollow tubular element a and a mouthpiece element, the length of the downstream section is defined by the total length of the hollow tubular element and the mouthpiece element.

[0149] Providing a relatively long downstream section, which can be defined by a relatively long combination of hollow tubular elements and mouthpiece elements, ensures that a suitable length of the aerosol-generating article protrudes from the aerosol generator when the article is received inside. Such a suitable protrusion length facilitates the insertion and removal of the article from the device and ensures that the upstream portion of the article is suitably inserted into the device with a reduced risk of damage, especially during insertion.

[0150] The ratio of the length of the downstream section to the total length of the aerosol-generating article may be about 0.80 or less. Preferably, the ratio of the length of the downstream section to the total length of the aerosol-generating article may be about 0.75 or less. More preferably, the ratio of the length of the downstream section to the total length of the aerosol-generating article may be about 0.70 or less. Even more preferably, the ratio of the length of the downstream section to the total length of the aerosol-generating article may be about 0.65 or less.

[0151] The ratio of the length of the downstream section to the total length of the aerosol-generating article may be at least about 0.30. Preferably, the ratio may be at least about 0.40. More preferably, the ratio may be at least about 0.50. Even more preferably, the ratio may be at least about 0.60.

[0152] In some embodiments, the ratio of the length of the downstream section to the total length of the aerosol-generating article is about 0.30 to about 0.80, preferably about 0.40 to about 0.80, more preferably about 0.50 to about 0.80, and even more preferably about 0.60 to about 0.80. In other embodiments, the ratio of the length of the downstream section to the total length of the aerosol-generating article is about 0.30 to about 0.75, preferably about 0.40 to about 0.75, more preferably about 0.50 to about 0.75, and even more preferably about 0.60 to about 0.75. In further embodiments, the ratio of the length of the downstream section to the total length of the aerosol-generating article is about 0.30 to about 0.70, preferably about 0.40 to about 0.70, more preferably about 0.50 to about 0.70, and even more preferably about 0.60 to about 0.70. As an example, the ratio of the length of the downstream section to the total length of the aerosol-generating article can be approximately 0.60 to 0.65, and more preferably, the ratio can be 0.62.

[0153] The ratio of the length of the downstream section to the length of the upstream section may be about 18 or less. Preferably, the ratio may be about 12 or less. More preferably, the ratio may be about 8 or less. Even more preferably, the ratio may be about 6 or less.

[0154] The ratio of the length of the downstream section to the length of the upstream section may be at least about 2.5. Preferably, the ratio may be at least about 3. More preferably, the ratio may be at least about 4. Even more preferably, the ratio may be at least about 5.

[0155] In some embodiments, the ratio of the length of the downstream section to the length of the upstream section is about 2.5 to about 18, preferably about 3 to about 18, more preferably about 4 to about 18, and even more preferably about 5 to about 18. In other embodiments, the ratio of the length of the downstream section to the length of the upstream section is about 2.5 to about 12, preferably about 3 to about 12, more preferably about 4 to about 12, and even more preferably about 5 to about 12. In further embodiments, the ratio of the length of the downstream section to the length of the upstream section is about 2.5 to about 8, preferably about 3 to about 8, more preferably about 4 to about 8, and even more preferably about 5 to about 8. As an example, the ratio of the length of the downstream section to the length of the upstream section may be about 6, and even more preferably about 5.6.

[0156] The ratio of the length of the aerosol generating element (in other words, the rod of the aerosol generating substrate) to the length of the downstream section may be about 0.80 or less. Preferably, the ratio of the length of the aerosol generating element to the length of the downstream section may be about 0.70 or less. More preferably, the ratio of the length of the aerosol generating element to the length of the downstream section may be about 0.60 or less. Even more preferably, the ratio of the length of the aerosol generating element to the length of the downstream section may be about 0.50 or less.

[0157] The ratio of the length of the aerosol generating element to the length of the downstream section may be at least about 0.20. Preferably, the ratio may be at least about 0.25. More preferably, the ratio may be at least about 0.30. Even more preferably, the ratio may be at least about 0.40.

[0158] In some embodiments, the ratio of the length of the aerosol generating element to the length of the downstream section is about 0.20 to about 0.80, preferably about 0.25 to about 0.80, more preferably about 0.30 to about 0.80, and even more preferably about 0.40 to about 0.80. In other embodiments, the ratio of the length of the aerosol generating element to the length of the downstream section is about 0.20 to about 0.70, preferably about 0.25 to about 0.70, more preferably about 0.30 to about 0.70, and even more preferably about 0.40 to about 0.70. In further embodiments, the ratio of the length of the aerosol generating element to the length of the downstream section is about 0.20 to about 0.60, preferably about 0.25 to about 0.60, more preferably about 0.30 to about 0.60, and even more preferably about 0.40 to about 0.60. As an example, the ratio of the length of the aerosol generating element to the length of the downstream section may be about 0.5, more preferably about 0.45, and even more preferably about 0.43.

[0159] The downstream section of the aerosol generating article according to the present invention includes a hollow tubular element. The hollow tubular element is preferably provided downstream of the rod of the aerosol generating substrate. The hollow tubular element may be provided immediately downstream of the rod of the aerosol generating substrate. In other words, the hollow tubular element may abut the downstream end of the rod of the aerosol generating substrate. The hollow tubular element may define the upstream end of the downstream section of the aerosol generating article. The hollow tubular element may be located between the rod of the aerosol generating substrate and the downstream end of the aerosol generating article. The downstream end of the aerosol generating article may coincide with the downstream end of the downstream section. The downstream section of the aerosol generating article preferably includes a single hollow tubular element. In other words, the downstream section of the aerosol generating article may include only one hollow tubular element.

[0160] Where used throughout this disclosure, the terms “hollow tubular segment” or “hollow tubular element” generally mean 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 an uninterrupted fluid communication between the upstream and downstream ends of the tubular element. However, naturally, alternative shapes of tubular segments (e.g., alternative cross-sectional shapes) may be possible. A hollow tubular segment or element may be an individual element of an aerosol-generating article having a defined length and thickness.

[0161] The internal volume defined by the hollow tubular element may be at least about 100 cubic millimeters. In other words, the volume of the cavity or lumen defined by the hollow tubular element may be at least about 100 cubic millimeters. Preferably, the internal volume defined by the hollow tubular element may be at least about 300 cubic millimeters. The internal volume defined by the hollow tubular element may be at least about 700 cubic millimeters.

[0162] The internal volume defined by the hollow tubular element may be about 1200 cubic millimeters or less. Preferably, the internal volume defined by the hollow tubular element may be about 1000 cubic millimeters or less. The internal volume defined by the hollow tubular element may be about 900 cubic millimeters or less.

[0163] The internal volume defined by the hollow tubular element may be about 100 to about 1200 cubic millimeters. Preferably, the internal volume defined by the hollow tubular element may be about 300 to about 1000 cubic millimeters. The internal volume defined by the hollow tubular element may be about 700 to 900 cubic millimeters.

[0164] In the context of the present invention, the hollow tubular segment provides an unlimited flow channel. This means that the hollow tubular segment 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 length hollow tubular segment or hollow tubular element, preferably less than 0.4 mmH2O per 10 mm length hollow tubular segment or hollow tubular element, and more preferably less than 0.1 mmH2O per 10 mm length hollow tubular segment or hollow tubular element.

[0165] The RTD of the hollow tubular element is preferably about 10 mmH2O or less. The RTD of the hollow tubular element is more preferably about 5 mmH2O or less. The RTD of the hollow tubular element is even more preferably about 2.5 mmH2O or less. The RTD of the hollow tubular element is even more preferably about 2 mmH2O or less. The RTD of the hollow tubular element is even more preferably about 1 mmH2O or less.

[0166] The RTD of the hollow tubular element may be at least 0 mmH2O, or at least about 0.25 mmH2O, or at least about 0.5 mmH2O, or at least about 1 mmH2O.

[0167] In some embodiments, the RTD of the hollow tubular element is about 0 mmH2O to about 10 mmH2O, preferably about 0.25 mmH2O to about 10 mmH2O, and more preferably about 0.5 mmH2O to about 10 mmH2O. In other embodiments, the RTD of the hollow tubular element is about 0 mmH2O to about 5 mmH2O, preferably about 0.25 mmH2O to about 5 mmH2O, and more preferably about 0.5 mmH2O to about 5 mmH2O. In yet another embodiment, the RTD of the hollow tubular element is about 1 mmH2O to about 5 mmH2O. In a further embodiment, the RTD of the hollow tubular element is about 0 mmH2O to about 2.5 mmH2O, preferably about 0.25 mmH2O to about 2.5 mmH2O, and more preferably about 0.5 mmH2O to about 2.5 mmH2O. In further embodiments, the RTD of the hollow tubular element is about 0 mmH2O to about 2 mmH2O, preferably about 0.25 mmH2O to about 2 mmH2O, and more preferably about 0.5 mmH2O to about 2 mmH2O. In a particularly preferred embodiment, the RTD of the hollow tubular element is about 0 mmH2O.

[0168] In the aerosol-generating article according to the present invention, the overall RTD of the article depends essentially on the RTD of the rod, and optionally on the RTD of the mouthpiece element and / or the upstream plug. This is because the hollow tubular segment is substantially empty and therefore contributes only substantially minimally to the overall RTD of the aerosol-generating article.

[0169] Therefore, the flow channel should not contain any components that would obstruct the longitudinal airflow. Preferably, the flow channel is substantially empty.

[0170] In this specification, “hollow tubular segment” or “hollow tubular element” may also be referred to as “hollow tube” or “hollow tube segment.”

[0171] A hollow tubular element may include one or more hollow tubular segments. Preferably, a hollow tubular element consists of one (single) hollow tubular segment. Preferably, a hollow tubular element consists of a series of hollow tubular segments. A hollow tubular segment may include any of the features described herein in relation to a hollow tubular element.

[0172] As will be described in more detail in this disclosure, the aerosol generating article may have a ventilation zone located along the downstream section. More specifically, the aerosol generating article may have a ventilation zone located along a hollow tubular element. Such, or any, ventilation zones may extend through the peripheral wall of the hollow tubular element. Thus, fluid communication is established between the flow channel internally defined by the hollow tubular element and the external environment. The ventilation zones are described further in this disclosure.

[0173] The length of the hollow tubular element may be at least about 15 mm. The length of the hollow tubular element may be at least about 17 mm. The length of the hollow tubular element may be at least about 19 mm.

[0174] The length of the hollow tubular element may be approximately 30 mm or less. The length of the hollow tubular element may be approximately 25 mm or less. The length of the hollow tubular element may be approximately 23 mm or less.

[0175] The length of the hollow tubular element may be approximately 15 mm to 30 mm. The length of the hollow tubular element may be approximately 17 mm to 25 mm. The length of the hollow tubular element may be approximately 19 mm to 23 mm.

[0176] Preferably, the length of the hollow tubular element may be about 21 mm.

[0177] The relatively long, hollow, tubular elements provide and define 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.

[0178] The ratio of the length of the aerosol generating element (in other words, the rod of the aerosol generating substrate) to the length of the hollow tubular element may be about 1.25 or less. Preferably, the ratio of the length of the aerosol generating element to the length of the hollow tubular element may be about 1 or less. More preferably, the ratio of the length of the aerosol generating element to the length of the hollow tubular element may be about 0.75 or less. Even more preferably, the ratio of the length of the aerosol generating element to the length of the hollow tubular element may be about 0.60 or less.

[0179] The ratio of the length of the aerosol generating element to the length of the hollow tubular element may be at least about 0.25. Preferably, the ratio of the length of the aerosol generating element to the length of the hollow tubular element may be at least about 0.30. More preferably, the ratio of the length of the aerosol generating element to the length of the hollow tubular element may be at least about 0.40. Even more preferably, the ratio of the length of the aerosol generating element to the length of the hollow tubular element may be at least about 0.50.

[0180] In some embodiments, the ratio of the length of the aerosol generating element to the length of the hollow tubular element is about 0.25 to about 1.25, preferably about 0.30 to about 1.25, more preferably about 0.40 to about 1.25, and even more preferably about 0.50 to about 1.25. In other embodiments, the ratio of the length of the aerosol generating element to the length of the hollow tubular element is about 0.25 to about 1, preferably about 0.30 to about 1, more preferably about 0.40 to about 1, and even more preferably about 0.50 to about 1. In further embodiments, the ratio of the length of the aerosol generating element to the length of the hollow tubular element is about 0.25 to about 0.75, preferably about 0.30 to about 0.75, more preferably about 0.40 to about 0.75, and even more preferably about 0.50 to about 0.75. For example, the ratio of the length of the aerosol generating element to the length of the hollow tubular element may be about 0.6, more preferably about 0.57.

[0181] The ratio of the length of the hollow tubular element to the length of the downstream section may be about 1 or less. Preferably, the ratio may be about 0.90 or less. More preferably, the ratio may be about 0.85 or less. Even more preferably, the ratio may be about 0.80 or less.

[0182] The ratio of the length of the hollow tubular element to the length of the downstream section may be at least about 0.35. Preferably, the ratio may be at least about 0.45. More preferably, the ratio may be at least about 0.50. Even more preferably, the ratio may be at least about 0.60.

[0183] In some embodiments, the ratio of the length of the hollow tubular element to the length of the downstream section is about 0.35 to about 1, preferably about 0.45 to about 1, more preferably about 0.50 to about 1, and even more preferably about 0.60 to about 1. In other embodiments, the ratio of the length of the hollow tubular element to the length of the downstream section is about 0.35 to about 0.90, preferably about 0.45 to about 0.90, more preferably about 0.50 to about 0.90, and even more preferably about 0.60 to about 0.90. In further embodiments, the ratio of the length of the hollow tubular element to the length of the downstream section is about 0.35 to about 0.85, preferably about 0.45 to about 0.85, more preferably about 0.50 to about 0.85, and even more preferably about 0.60 to about 0.85. As an example, the ratio of the length of the hollow tubular element to the length of the downstream section is preferably about 0.75.

[0184] The ratio of the length of the hollow tubular element to the overall length of the aerosol generating article may be about 0.80 or less. Preferably, the ratio may be about 0.70 or less. More preferably, the ratio may be about 0.60 or less. Even more preferably, the ratio may be about 0.50 or less.

[0185] The ratio of the length of the hollow tubular element to the overall length of the aerosol generating article may be at least about 0.25. Preferably, the ratio may be at least about 0.30. More preferably, the ratio may be at least about 0.40. Even more preferably, the ratio may be at least about 0.45.

[0186] In some embodiments, the ratio of the length of the hollow tubular element to the overall length of the aerosol-generating article is about 0.25 to about 0.80, preferably about 0.30 to about 0.80, more preferably about 0.40 to about 0.80, and even more preferably about 0.45 to about 0.80. In other embodiments, the ratio of the length of the hollow tubular element to the overall length of the aerosol-generating article is about 0.25 to about 0.70, preferably about 0.30 to about 0.70, more preferably about 0.40 to about 0.70, and even more preferably about 0.45 to about 0.70. In further embodiments, the ratio of the length of the hollow tubular element to the overall length of the aerosol-generating article is about 0.25 to about 0.60, preferably about 0.30 to about 0.60, more preferably about 0.40 to about 0.60, and even more preferably about 0.45 to about 0.60. As an example, the ratio of the length of the hollow tubular element to the overall length of the aerosol-generating article may be about 0.5, more preferably about 0.47.

[0187] Providing a downstream section or hollow tubular element having the ratios listed above maximizes the aerosol cooling and formation advantages of having a relatively long hollow tubular element, while providing sufficient filtration for aerosol-generating articles configured to be heated rather than burned. Furthermore, providing a longer hollow tubular 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 mouthpiece filtration element.

[0188] The thickness of the peripheral wall of the hollow tubular element (in other words, the wall thickness) may be at least about 100 micrometers. The wall thickness of the hollow tubular element may be at least about 150 micrometers. The wall thickness of the hollow tubular element may be at least about 200 micrometers, preferably at least about 250 micrometers, and more preferably at least about 500 micrometers (or 0.5 mm).

[0189] The wall thickness of the hollow tubular element may be about 2 mm or less, preferably about 1.5 mm or less, and more preferably about 1.25 mm or less. The wall thickness of the hollow tubular element may be about 1 mm or less. The wall thickness of the hollow tubular element may be about 500 micrometers or less.

[0190] The wall thickness of the hollow tubular element may be about 100 micrometers to about 2 millimeters, preferably about 150 micrometers to about 1.5 millimeters, and more preferably about 200 micrometers to about 1.25 millimeters.

[0191] The wall thickness of the hollow tubular element is preferably about 250 micrometers (0.25 mm).

[0192] Simultaneously, by maintaining a relatively low thickness of the peripheral walls of the hollow tubular segment, it is ensured that the overall internal volume of the hollow tubular segment is effectively maximized, so that the aerosol components become available for the aerosol to initiate the nucleation process as soon as they leave the rod of the aerosol generating substrate, and that the cross-sectional area of ​​the hollow tubular segment is effectively maximized, while at the same time ensuring that the hollow tubular segment has the structural strength necessary to prevent the collapse of the aerosol generating article and provide some support to the rod of the aerosol generating substrate, and that the RTD of the hollow tubular segment is minimized. The large value of the cross-sectional area of ​​the cavity of the hollow tubular segment is understood to be associated with a reduced velocity of the aerosol flow moving along the aerosol generating article, and is further expected to work favorably for aerosol nucleation. Furthermore, by utilizing a hollow tubular segment with a relatively thin thickness, it is possible to substantially prevent the diffusion of the venting air before it comes into contact with and mixes with the aerosol flow, and is further understood to work favorably for the nucleation phenomenon. In practice, it is possible to improve the cooling effect on the formation of new aerosol particles by providing more controllable and localized cooling of the flow of volatile seeds.

[0193] The hollow tubular 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.

[0194] The hollow tubular element may have an outer diameter of 5 to 12 mm, for example, 5 to 10 mm, or 6 to 8 mm. In a preferred embodiment, the hollow tubular element has an outer diameter of 7.2 mm plus or minus 10 percent.

[0195] A hollow tubular element may have an inner diameter. Preferably, the hollow tubular element may have a constant inner diameter along its length. However, the inner diameter of the hollow tubular element may vary along its length.

[0196] The hollow tubular element may have an inner diameter of at least about 2 millimeters. For example, the hollow tubular element may have an inner diameter of at least about 4 millimeters, or at least about 5 millimeters, or at least about 7 millimeters.

[0197] Providing a hollow tubular element having the inner diameter described above can be advantageous in that it may provide sufficient rigidity and strength to the hollow tubular element.

[0198] The hollow tubular element may have an inner diameter of about 10 millimeters or less. For example, the hollow tubular element may have an inner diameter of about 9 millimeters or less, about 8 millimeters or less, or about 7.5 millimeters or less.

[0199] Providing a hollow tubular element having the aforementioned inner diameter is advantageous in that it can reduce the draw resistance of the hollow tubular segment.

[0200] The hollow tubular elements may have an inner diameter of approximately 2 mm to 10 mm, approximately 4 mm to 9 mm, approximately 5 mm to 8 mm, or 6 mm to 7.5 mm.

[0201] The hollow tubular element may have an outer diameter of approximately 7.1 or 7.2 mm. The hollow tubular element may have an inner diameter of approximately 6.7 mm.

[0202] The ratio of the inner diameter to the outer diameter of a hollow tubular element can be at least about 0.8. For example, the ratio of the inner diameter to the outer diameter of a hollow tubular element can be at least about 0.85, at least about 0.9, or at least about 0.95.

[0203] The ratio of the inner diameter to the outer diameter of a hollow tubular element may be approximately 0.99 or less. For example, the ratio of the inner diameter to the outer diameter of a hollow tubular element may be approximately 0.98 or less.

[0204] The ratio of the inner diameter of a hollow tubular element to the outer diameter of a hollow tubular element may be approximately 0.97.

[0205] By providing a relatively large inner diameter, the draw resistance of the hollow tubular segment is advantageously reduced, which can improve the cooling and nucleation of aerosol particles.

[0206] The lumen or cavity of a hollow tubular segment may have any cross-sectional shape. The lumen of a hollow tubular segment may have a circular cross-sectional shape.

[0207] The hollow tubular segment may include a paper-based material. The hollow tubular segment may include 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.

[0208] Preferably, the hollow tubular element may include cardboard. The hollow tubular element may be a cardboard tube. The hollow tubular 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 articles into the aerosol generator and being rigid enough to provide good engagement between the articles and the inside of the device. Thus, cardboard tubes may provide good resistance to deformation or compression during use.

[0209] The hollow tubular segment may be a paper tube. The hollow tubular segment may be a tube formed from spirally wound paper. The hollow tubular segment may be formed from multiple layers of paper. The paper may have a basis weight of at least about 50 grams per square meter, at least about 60 grams per square meter, at least about 70 grams per square meter, or at least about 90 grams per square meter.

[0210] The hollow tubular segment may contain polymer materials. For example, the hollow tubular segment may contain a polymer film. The polymer film may contain a cellulose film. The hollow tubular segment may contain low-density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers. The hollow tube may contain cellulose acetate tow.

[0211] If the hollow tubular segments contain cellulose acetate tow, the cellulose acetate tow can have about 2 to about 4 denier per filament and about 25 to about 40 total denier.

[0212] As described above, the aerosol generating article according to the present invention includes a downstream section comprising a hollow tubular element installed downstream of the rod of the aerosol generating substrate and in contact with the downstream end of the rod of the aerosol generating substrate. Furthermore, the aerosol generating article according to the present invention includes a ventilation zone located along the hollow tubular element.

[0213] In this way, a ventilated cavity is provided downstream of the rod of the aerosol generating substrate. This offers several potential technical advantages.

[0214] Firstly, the inventors found that one such ventilated, hollow tubular element provides particularly efficient cooling of the aerosol. Thus, satisfactory cooling of the aerosol can be achieved even by a relatively short downstream section. This is particularly desirable because it allows aerosol-generating substrates (and especially those containing tobacco) to provide aerosol-generating articles that are heated rather than burned, combining satisfactory aerosol delivery with efficient cooling of the aerosol to a temperature desirable for the consumer.

[0215] Secondly, the inventors surprisingly found that the rapid cooling of volatile species released when the aerosol-generating substrate is heated promotes enhanced nucleation of aerosol particles. This effect is particularly noticeable when the ventilation zone is positioned in a precisely defined location along the length of the hollow tubular 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 has a remarkable ability to counteract the potentially undesirable effect of dilution induced by the introduction of ventilation air.

[0216] The distance between the ventilation zone and the upstream end of the downstream section is at least 26 millimeters. As used herein, the term “distance between the ventilation zone and another element or part of the aerosol-generating article” refers to a distance measurement in the longitudinal direction, i.e., in a direction extending along or parallel to the cylindrical axis of the aerosol-generating article.

[0217] The distance between the ventilation zone and the upstream end of the upstream section is preferably at least 27 millimeters.

[0218] 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 section is 33 millimeters or less. More preferably, the distance between the ventilation zone and the upstream end of the upstream section is 31 millimeters or less.

[0219] In some embodiments, the distance between the ventilation zone and the upstream end of the upstream section is 25 to 34 millimeters, preferably 26 to 34 millimeters, and more preferably 27 to 34 millimeters.

[0220] 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.

[0221] 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.

[0222] In some particularly preferred embodiments, the distance between the ventilation zone and the upstream end of the upstream element is 28 to 30 millimeters.

[0223] Aerosol-generating articles having a ventilation zone located along a hollow tubular element at a distance from the upstream end of the upstream element within the aforementioned range have been found to offer several advantages.

[0224] Firstly, it has been observed that such articles deliver particularly satisfactory aerosols to consumers, especially when the aerosol-generating substrate contains tobacco.

[0225] While not intended to be theoretically constrained, the intense cooling caused by ambient air drawn into the cavities of the hollow tube segments in the ventilation zone is understood to accelerate the condensation of droplets of aerosol-forming material (e.g., glycerin) released from the aerosol-generating substrate during 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. As a result, the overall ratio of the aerosol particle phase to the aerosol gas phase may be improved compared to existing aerosol-generating articles.

[0226] By positioning the ventilation zone at a distance from the upstream end of the upstream element described above, the flight time of volatile nicotine particles is 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 there is sufficient time and space for nicotine accumulation and nicotine salt formation to occur at a considerable rate before the aerosol flow reaches the consumer's mouth.

[0227] The ventilation zone may typically include a plurality of perforations running through the peripheral wall of a hollow tubular element. Preferably, the ventilation zone includes at least one row of perforations around the periphery. In some embodiments, the ventilation zone may include two rows of perforations around the periphery. For example, the perforations may be formed online during the manufacture of the aerosol-generating article. Each circumferential row of perforations preferably contains 8 to 30 perforations.

[0228] The aerosol-generating article according to the present invention may have a breathability level of at least about 2 percent.

[0229] The term "ventilation level" is used throughout this specification to mean the volume ratio of the airflow entering the aerosol-generating article through the ventilation zone (ventilation airflow) to 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.

[0230] The aerosol-generating article according to the present invention may have a ventilation level of up to approximately 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.

[0231] Therefore, the aerosol-generating article according to the present invention may have a breathability 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 a breathability 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 a breathability 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 a breathability 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 a breathability 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.

[0232] 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 particularly preferred embodiments, 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.

[0233] 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 element through a ventilation zone may have a favorable effect on the nucleation and growth of aerosol particles.

[0234] 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. The 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 within 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 droplets are assumed to appear with a specific 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 one identical mechanism: the transfer of mass between liquid and gas. Evaporation involves net mass transfer from the droplet phase to the gas phase, while condensation is net mass transfer from the gas phase to the droplet phase. Due to evaporation (or condensation), the droplet shrinks (or grows), but the number of droplets does not change.

[0235] In this scenario, which can be 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 hypothesize that cooling can cause 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.

[0236] Therefore, rapid cooling induced by introducing outside air into a hollow tubular element through a ventilation zone can be advantageously used for favorable nucleation and growth of aerosol droplets. However, at the same time, introducing outside air into a hollow tubular element has the direct disadvantage of diluting the aerosol flow delivered to the consumer.

[0237] 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. Therefore, satisfactory values ​​of aerosol delivery are consistently achieved by the aerosol-generating article according to the present invention.

[0238] The inventors also found, surprisingly, that the dilution effect on aerosols, which can be evaluated by measurement, specifically the effect on the delivery of aerosol-forming materials (e.g., glycerol) contained within the aerosol-generating substrate, is advantageously minimized when the permeability level is within the aforementioned range.

[0239] 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.

[0240] This is particularly advantageous for “short” aerosol-generating articles, such as those in which the length of the aerosol-generating substrate rod is less than about 40 millimeters, preferably less than 30 millimeters, more preferably less than 25 millimeters, and especially preferably less than 20 millimeters, or in which the overall length of the aerosol-generating article is less than about 70 millimeters, preferably less than about 60 millimeters, and more preferably less than 50 millimeters. As will be understood, in such aerosol-generating articles there is typically little time and space for aerosol formation and for the aerosol particle phase to become available for delivery to consumers, and thus the advantages of the enhanced nucleation described above are felt in a particularly remarkable manner.

[0241] Furthermore, since the vented hollow tubular elements substantially do not contribute to the overall RTD of the aerosol-generating article, the overall RTD of the article can be advantageously fine-tuned in the aerosol-generating article according to the present invention by adjusting the length and density of the rods of the aerosol-generating substrate, or the length of any segment of the filter material forming part of the downstream section (e.g., mouthpiece element), and optionally the length and density of the segments of the filter material provided upstream of the aerosol-generating substrate and susceptor element. Thus, it is possible to consistently and very accurately manufacture aerosol-generating articles having a predetermined RTD so that a satisfactory level of RTD can be provided to consumers, even in the presence of venting.

[0242] The distance between the ventilation zone and the downstream end of the rod of the aerosol generating substrate may be at least 4 mm, 6 mm, or 8 mm. Preferably, the distance between the ventilation zone and the downstream end of the rod of the aerosol generating substrate is at least 9 mm. More preferably, the distance between the ventilation zone and the downstream end of the rod of the aerosol generating substrate is at least 10 mm.

[0243] 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.

[0244] 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. Positioning the ventilation zone slightly away from the downstream end of the rod of the aerosol generating substrate within the above range generally has the advantage of ensuring that the ventilation zone is just outside the heating device when the aerosol generating article is inserted into the heating device during use. Additionally, it has been found that positioning the ventilation zone slightly away from the downstream end of the aerosol-generating substrate rod within the aforementioned range can advantageously enhance nucleation and aerosol formation and delivery.

[0245] The distance between the ventilation zone and the downstream end of the hollow tubular element may be at least 3 millimeters. Preferably, the distance between the ventilation zone and the downstream end of the hollow tubular element is at least 5 millimeters. More preferably, the distance between the ventilation zone and the downstream end of the hollow tubular element is at least 7 millimeters.

[0246] The distance between the ventilation zone and the downstream end of the hollow tubular element is preferably 14 millimeters or less. More preferably, the distance between the ventilation zone and the downstream end of the hollow tubular element is 12 millimeters or less. Even more preferably, the distance between the ventilation zone and the downstream end of the hollow tubular element is 10 millimeters or less.

[0247] In some embodiments, the distance between the ventilation zone and the downstream end of the hollow tubular 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 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 element is 3 to 10 millimeters, preferably 5 to 10 millimeters, and more preferably 7 to 10 millimeters.

[0248] Positioning the ventilation zone slightly away from the downstream end of the hollow tubular element within the aforementioned range has the advantage of generally ensuring that the ventilation zone is just outside the heating device when the aerosol-generating article is inserted into the heating device during use. Additionally, it has been found that positioning the ventilation zone slightly away from the downstream end of the hollow tubular element within the aforementioned range may advantageously lead to the formation and delivery of a relatively more uniform aerosol.

[0249] 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.

[0250] 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.

[0251] 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.

[0252] Positioning the ventilation zone slightly away from the downstream end of the aerosol-generating article within the aforementioned range has the advantage of generally ensuring that, when the aerosol-generating article is partially received into the heating device during use, the portion of the aerosol-generating article extending outside the heating device is long enough for the consumer to comfortably hold the article between their lips. At the same time, evidence suggests that if the length of the portion of the aerosol-generating article extending outside the heating device were longer, the aerosol-generating article could easily be bent in an inadequate and undesirable manner, which could impair aerosol delivery or the intended use of the aerosol-generating article in general.

[0253] As discussed in this disclosure, the downstream section may include a mouthpiece element. The mouthpiece element may extend from the downstream end of the downstream section. The mouthpiece element may be located at the downstream end of the aerosol generating article. The downstream end of the mouthpiece element may define the downstream end of the aerosol generating article.

[0254] The mouthpiece element may be provided downstream of the rod of the aerosol generating substrate. The mouthpiece element may extend all the way to the mouth end of the aerosol generating article. The mouthpiece element may comprise at least one mouthpiece filter segment formed from a fibrous filter material. The mouthpiece element may be located downstream of the hollow tubular element described above. The mouthpiece element may extend between the hollow tubular element and the downstream end of the aerosol generating article.

[0255] Parameters or characteristics described for the entire mouthpiece element may be equally applied to the mouthpiece filter segment of the mouthpiece element.

[0256] A fibrous filter material may be used to filter aerosols generated from an aerosol generating substrate. Suitable fibrous filter materials will be known to those skilled in the art. Particularly preferably, at least one mouthpiece filter segment includes a cellulose acetate filter segment formed from cellulose acetate tow.

[0257] In certain preferred embodiments, the mouthpiece element comprises a single mouthpiece filter segment. In alternative embodiments, the mouthpiece element comprises two or more mouthpiece filter segments aligned axially with end-to-end contact with one another.

[0258] In certain embodiments of the present invention, the downstream section may have an oral end recess at its downstream end, which is downstream of the mouthpiece element as described above. The oral end cavity may be defined by a further hollow tubular element provided at the downstream end of the mouthpiece. Alternatively, the oral end cavity may be defined by an outer wrapper of the aerosol generating article, which extends downstream from (or past) the mouthpiece element.

[0259] The mouthpiece element may optionally contain flavoring agents that can be provided in any preferred form. For example, the mouthpiece element may contain one or more capsules, flavoring agent beads or granules, or one or more flavoring threads or filaments.

[0260] The mouthpiece element, or its mouthpiece filter segment, preferably has a low particle filtration efficiency.

[0261] The mouthpiece element is preferably surrounded by a plug wrap. Preferably, the mouthpiece element is not ventilated so that air does not enter the aerosol-generating article along the mouthpiece element.

[0262] The mouthpiece element is preferably connected by a tip wrapper to one or more adjacent upstream components of the aerosol-generating article.

[0263] The mouthpiece element preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article. The diameter of the mouthpiece element (or mouthpiece filter segment) may be substantially the same as the outer diameter of the hollow tubular element. As described herein, the outer diameter of the hollow tubular element may be about 7.2 mm plus or minus 10 percent.

[0264] The diameter of the mouthpiece element may be approximately 5mm to 10mm. The diameter of the mouthpiece element may be approximately 6mm to 8mm. The diameter of the mouthpiece element may be approximately 7mm to 8mm. The diameter of the mouthpiece element may be approximately 7.2mm plus or minus 10 percent. The diameter of the mouthpiece element may be approximately 7.25mm plus or minus 10 percent.

[0265] Unless otherwise specified, the draw resistance (RTD) of a component or aerosol-generating article is measured in accordance with ISO 6565-2015. RTD refers to the pressure required to force air through the entire length of the component. The terms “pressure drop” or “draw resistance” of a component or article may also refer to “resistance to draw.” These terms typically refer to measurements performed in accordance with ISO 6565-2015 under test conditions of a volumetric flow rate of approximately 17.5 ml / second at the output or downstream end of the component being measured, at a temperature of approximately 22 degrees Celsius, a pressure of approximately 101 kPa (approximately 760 Torr), and a relative humidity of approximately 60%.

[0266] The downstream section draw-out resistance (RTD) may be at least about 0 mmH2O. The downstream section RTD may be at least about 3 mmH2O. The downstream section RTD may be at least about 6 mmH2O.

[0267] The RTD of the downstream section may be less than or equal to approximately 12 mmH2O. The RTD of the downstream section may not be greater than approximately 11 mmH2O. The RTD of the downstream section may not be greater than approximately 10 mmH2O.

[0268] The draw resistance of the downstream section may be about 0 mmH2O or more and less than about 12 mmH2O. Preferably, the draw resistance of the downstream section may be about 3 mmH2O or more and less than about 12 mmH2O. The draw resistance of the downstream section may be about 0 mmH2O or more and less than about 11 mmH2O. Even more preferably, the draw resistance of the downstream section may be about 3 mmH2O or more and less than about 11 mmH2O. Even more preferably, the draw resistance of the downstream section may be about 6 mmH2O or more and less than about 10 mmH2O. Preferably, the draw resistance of the downstream section may be about 8 mmH2O.

[0269] The draw-to-drop (RTD) characteristics of the downstream section may be entirely or almost entirely attributable to the RTD characteristics of the downstream section's mouthpiece element. In other words, the RTD of the downstream section's mouthpiece element may completely define the downstream section's RTD.

[0270] The draw-out resistance (RTD) of the mouthpiece element may be at least about 0 mmH2O. The RTD of the mouthpiece element may be at least about 3 mmH2O. The RTD of the mouthpiece element may be at least about 6 mmH2O.

[0271] The RTD of the mouthpiece element may be approximately 12 mmH2O or less. The RTD of the mouthpiece element may be approximately 11 mmH2O or less. The RTD of the mouthpiece element may be approximately 10 mmH2O or less.

[0272] The draw resistance of the mouthpiece element may be about 0 mmH2O or more and less than about 12 mmH2O. Preferably, the draw resistance of the mouthpiece element may be about 3 mmH2O or more and less than about 12 mmH2O. The draw resistance of the mouthpiece element may be about 0 mmH2O or more and less than about 11 mmH2O. Even more preferably, the draw resistance of the mouthpiece element may be about 3 mmH2O or more and less than about 11 mmH2O. Even more preferably, the draw resistance of the mouthpiece element may be about 6 mmH2O or more and less than about 10 mmH2O. Preferably, the draw resistance of the mouthpiece element may be about 8 mmH2O.

[0273] As described above, the mouthpiece element or mouthpiece filter segment may be formed from a fibrous material. The mouthpiece element may be formed from a porous material. The mouthpiece element may be formed from a biodegradable material. The mouthpiece element may be formed from a cellulose material such as cellulose acetate. For example, the mouthpiece element may be formed from a bundle of cellulose acetate fibers having about 10 to about 15 denier / filament. For example, the mouthpiece element may be formed from a relatively low-density cellulose acetate tow, such as a cellulose acetate tow containing fibers of about 12 denier / filament.

[0274] The mouthpiece element may be formed from a polylactic acid-based material. The mouthpiece element may also be formed from a bioplastic material, preferably a starch-based bioplastic material. The mouthpiece element may be manufactured by injection molding or extrusion molding. Bioplastic materials are advantageous because they can provide a mouthpiece element structure that is easy and inexpensive to manufacture, having a specific and complex cross-sectional profile that provides suitable RTD properties, and which may contain multiple relatively large airflow channels extending through the material of the mouthpiece element.

[0275] The mouthpiece element may be formed from a sheet of a suitable material that is crumpled, pleated, assembled, woven, or folded into elements defining multiple longitudinally extending channels. Such sheets of a suitable material may be formed from paper, cardboard, polymers such as polylactic acid, or any other cellulosic, paper-based, or bioplastic material. The cross-sectional profile of such a mouthpiece element may show randomly oriented channels.

[0276] The mouthpiece element may be formed in any other suitable manner. For example, the mouthpiece element may be formed from a bundle of longitudinally extending tubes. The longitudinally extending tubes may be formed from polylactic acid. The mouthpiece element may be formed by extrusion, molding, lamination, injection molding, or shredding of a suitable material. Therefore, it is preferable that there is a low pressure drop (or RTD) from the upstream end to the downstream end of the mouthpiece element.

[0277] The length of the mouthpiece element may be at least about 3 mm. The length of the mouthpiece element may be at least about 5 mm. The length of the mouthpiece element may be about 11 mm or less. The length of the mouthpiece element may be about 9 mm or less. The length of the mouthpiece element may be between about 3 mm and about 11 mm. The length of the mouthpiece element may be between about 5 mm and about 9 mm. Preferably, the length of the mouthpiece element may be about 7 mm.

[0278] The ratio of the length of the mouthpiece element to the length of the downstream section may be about 0.55 or less. Preferably, the ratio may be about 0.45 or less. More preferably, the ratio may be about 0.35 or less. Even more preferably, the ratio may be about 0.25 or less.

[0279] The ratio of the length of the mouthpiece element to the length of the downstream section may be at least about 0.05. Preferably, the ratio may be at least about 0.10. More preferably, the ratio may be at least about 0.15. Even more preferably, the ratio may be at least about 0.20.

[0280] In some embodiments, the ratio of the length of the mouthpiece element to the length of the downstream section is about 0.05 to about 0.55, preferably about 0.10 to about 0.55, more preferably about 0.15 to about 0.55, and even more preferably about 0.20 to about 0.55. In other embodiments, the ratio of the length of the mouthpiece element to the length of the downstream section is about 0.05 to about 0.45, preferably about 0.10 to about 0.45, more preferably about 0.15 to about 0.45, and even more preferably about 0.20 to about 0.45. In further embodiments, the ratio of the length of the mouthpiece element to the length of the downstream section is about 0.05 to about 0.35, preferably about 0.10 to about 0.35, more preferably about 0.15 to about 0.35, and even more preferably about 0.20 to about 0.35. As an example, the ratio of the length of the mouthpiece element to the length of the downstream section may preferably be about 0.20 to about 0.25, and more preferably, the ratio of the length of the mouthpiece element to the length of the downstream section may be about 0.25.

[0281] The ratio of the length of the mouthpiece element to the overall length of the aerosol generating article may be about 0.40 or less. Preferably, the ratio may be about 0.30 or less. More preferably, the ratio may be about 0.25 or less. Even more preferably, the ratio may be about 0.20 or less.

[0282] The ratio of the length of the mouthpiece element to the overall length of the aerosol generating article may be at least about 0.05. Preferably, the ratio may be at least about 0.07. More preferably, the ratio may be at least about 0.10. Even more preferably, the ratio may be at least about 0.15.

[0283] In some embodiments, the ratio of the length of the mouthpiece element to the overall length of the aerosol generating article is about 0.05 to about 0.40, preferably about 0.07 to about 0.40, more preferably about 0.10 to about 0.40, and even more preferably about 0.15 to about 0.40. In other embodiments, the ratio of the length of the mouthpiece element to the overall length of the aerosol generating article is about 0.05 to about 0.30, preferably about 0.07 to about 0.30, more preferably about 0.10 to about 0.30, and even more preferably about 0.15 to about 0.30. In further embodiments, the ratio of the length of the mouthpiece element to the overall length of the aerosol generating article is about 0.05 to about 0.25, preferably about 0.07 to about 0.25, more preferably about 0.10 to about 0.25, and even more preferably about 0.15 to about 0.25. As an example, the ratio of the length of the mouthpiece element to the total length of the aerosol generating article can be about 0.15 to about 0.20, and more preferably, the ratio can be about 0.16.

[0284] In embodiments where the downstream section includes a hollow tubular element and a mouthpiece element, the ratio of the length of the hollow tubular element to the length of the mouthpiece element may be at least about 1.25. In other words, the length of the hollow tubular element may be equivalent to about 125% of the length of the mouthpiece. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be at least about 1.5. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be at least about 2.

[0285] The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be approximately 8.5 or less. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be approximately 6 or less. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be approximately 4 or less.

[0286] The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be approximately 1.25 to approximately 8.5. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be approximately 1.5 to approximately 6. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be approximately 2 to approximately 4.

[0287] Preferably, the ratio of the length of the hollow tubular element to the length of the mouthpiece element may be about 3. In such embodiments, the length of the hollow tubular element is about 21 mm, and the length of the mouthpiece element is about 7 mm.

[0288] The aerosol-generating article may have a total length of approximately 35 mm to approximately 100 mm.

[0289] The total length of the aerosol generating article according to the present invention is preferably at least about 38 millimeters. More preferably, the total length of the aerosol generating article according to the present invention is at least about 40 millimeters. Even more preferably, the total length of the aerosol generating article according to the present invention is at least about 42 millimeters.

[0290] The total length of the aerosol generating article according to the present invention is preferably 70 millimeters or less. More preferably, the total length of the aerosol generating article according to the present invention is preferably 60 millimeters or less. Even more preferably, the total length of the aerosol generating article according to the present invention is preferably 50 millimeters or less.

[0291] In some embodiments, the total length of the aerosol generating article is preferably about 38 mm to about 70 mm, more preferably about 40 mm to about 70 mm, and even more preferably about 42 mm to about 70 mm. In other embodiments, the total length of the aerosol generating article is preferably about 38 mm to about 60 mm, more preferably about 40 mm to about 60 mm, and even more preferably about 42 mm to about 60 mm. In further embodiments, the total length of the aerosol generating article is preferably about 38 mm to about 50 mm, more preferably about 40 mm to about 50 mm, and even more preferably about 42 mm to about 50 mm. In an exemplary embodiment, the total length of the aerosol generating article is about 45 mm.

[0292] The aerosol-generating article has an outer diameter of at least 5 mm. Preferably, the aerosol-generating article has an outer diameter of at least 6 mm. More preferably, the aerosol-generating article has an outer diameter of at least 7 mm.

[0293] The aerosol generating article preferably has an outer diameter of about 12 mm or less. More preferably, the aerosol generating article has an outer diameter of about 10 mm or less. Even more preferably, the aerosol generating article has an outer diameter of about 8 mm or less.

[0294] In some embodiments, the aerosol-generating article has an outer diameter of from about 5 millimeters to about 12 millimeters, preferably from about 6 millimeters to about 12 millimeters, more preferably from about 7 millimeters to about 12 millimeters. In other embodiments, the aerosol-generating article has an outer diameter of from about 5 millimeters to about 10 millimeters, preferably from about 6 millimeters to about 10 millimeters, more preferably from about 7 millimeters to about 10 millimeters. In further embodiments, the aerosol-generating article has an outer diameter of from about 5 millimeters to about 8 millimeters, preferably from about 6 millimeters to about 8 millimeters, more preferably from about 7 millimeters to about 8 millimeters.

[0295] The outer diameter of the aerosol-generating article may be substantially constant over the entire length of the article. Alternatively, different portions of the aerosol-generating article may have different outer diameters.

[0296] In particularly preferred embodiments, one or more of the components of the aerosol-generating article are individually surrounded by their own wrapper.

[0297] In one embodiment, the rod and mouthpiece element of the aerosol-generating substrate are individually wrapped. The upstream element, the rod of the aerosol-generating substrate, and the hollow tubular element are then combined together with an outer wrapper. Thereafter, they are combined with the mouthpiece element having its own wrapper by tipping paper.

[0298] Preferably, at least one of the components of the aerosol-generating article is wrapped in a hydrophobic wrapper.

[0299] 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 that has traditionally been measured through the liquid, where the liquid / vapor interface meets the solid surface. This quantifies the wetting of the solid surface by the liquid via Young's equation. The hydrophobicity or water contact angle may be determined by utilizing the TAPPI T558 test method, and the results are expressed as the interfacial contact angle and reported in "degrees", which can range from approximately 0 to approximately 180 degrees.

[0300] In a preferred embodiment, the hydrophobic wrapper comprises a paper layer having a water contact angle of about 30 degrees or more, preferably about 35 degrees or more, or about 40 degrees or more, or about 45 degrees or more.

[0301] By way of example, the paper layer may contain PVOH (polyvinyl alcohol) or silicon. The PVOH may be applied to the paper layer as a surface coating, or the paper layer may include a surface treatment containing PVOH or silicon.

[0302] 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 element located immediately downstream of the rod of the aerosol-generating substrate, a mouthpiece element located immediately downstream of the aerosol-cooling element, and one or more outer wrappers combining the upstream element, the rod of the aerosol-generating substrate, the hollow tubular element, and the mouthpiece element. The upstream element defines the upstream section of the aerosol-generating article. The hollow tubular element and the mouthpiece element form the downstream section of the aerosol-generating article.

[0303] The rod of the aerosol-generating substrate may abut against the upstream element. The hollow tubular element may abut against the rod of the aerosol-generating substrate. The mouthpiece element may abut against the hollow tubular element. Preferably, the hollow tubular element abuts against the rod of the aerosol-generating substrate, and the mouthpiece element abuts against the hollow tubular element.

[0304] The aerosol-generating article has a substantially cylindrical shape and an outer diameter of 7.23 millimeters.

[0305] The upstream element defined within the upstream section has a length of 5 mm, the rod of the aerosol generating article has a length of 12 mm, the hollow tubular element has a length of 21 mm, and the mouthpiece element has a length of 7 mm. Therefore, the length of the downstream section is 28 mm, and the total length of the aerosol generating article is approximately 45 mm. Thus, the combined length of the hollow tubular element and the mouthpiece element is 28 mm.

[0306] The upstream element is in the form of a hollow plug made of cellulose acetate tow wound within a rigid plug wrap.

[0307] The rod of the aerosol generating substrate comprises at least one of the above-described aerosol generating substrates, and preferably shredded tobacco material. In a preferred embodiment, the rod of the aerosol generating substrate comprises 150 milligrams of shredded tobacco material containing 13 to 18 weight percent glycerol.

[0308] More specifically, the hollow tubular element is in the form of a cardboard tube and also has an inner diameter of approximately 6.7 millimeters. Therefore, the thickness of the peripheral wall of the hollow tubular segment is approximately 0.25 millimeters.

[0309] A ventilation zone with a row of circumferential openings is installed along the hollow tubular element at 12 millimeters from the upstream end of the hollow tubular element and at 29 millimeters from the upstream end of the upstream element.

[0310] The mouthpiece is in the form of low-density cellulose acetate filter segments.

[0311] As described above, the 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.

[0312] The device cavity may be referred to as the heating chamber of the aerosol generator. The device cavity may extend between a distal end and a mouth end or proximal end. The distal end of the device cavity may be a closed end, and the mouth end 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.

[0313] 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.

[0314] The length of the device cavity may be approximately 10 mm to 50 mm. The length of the device cavity may be approximately 20 mm to 40 mm. The length of the device cavity may be approximately 25 mm to 30 mm.

[0315] 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. The length of the device cavity may be configured 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 configured such that when the aerosol generating article is received into the device cavity, a portion of the downstream section (such as a hollow tubular element or mouthpiece element) protrudes from the device cavity. The length of the device cavity may be configured such that when the aerosol generating article is received into the device cavity, a portion of the downstream section (such as a hollow tubular element or mouthpiece element) is received into the device cavity.

[0316] 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 into 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 into the device.

[0317] 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 into 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 into 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 into the device. Various lengths of the hollow tubular element are described in more detail in this disclosure.

[0318] Optimizing the amount or length of an article inserted into an aerosol generating device may increase the resistance to accidental removal of the article 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 the article inserted into the device can engage in frictional contact with the device cavity. The inserted portion of the article, or the portion of the article configured to be received within the device cavity, may be the same length as the device cavity.

[0319] The length of the device cavity is preferably from about 25 mm to about 29 mm. More preferably, the length of the device cavity is from about 26 mm to about 29 mm. Even more preferably, the length of the device cavity is about 27 mm or about 28 mm.

[0320] The combined length of the upstream section (or element) and the inserted portion of the downstream section or hollow tubular element is preferably equivalent to about 80 percent to about 120 percent of the length of the protruding portion of the aerosol generating article. The downstream section or hollow tubular element or the inserted portion of the aerosol generating article refers to the portion of the downstream section or hollow tubular element or aerosol generating article that is configured to be positioned within the device cavity when the aerosol generating article is received therein. The protruding portion of the aerosol generating article refers to the article that is configured to be positioned outside the device cavity or to protrude from the device when the aerosol generating article is received therein. The inventors have found that such relationships minimize the risk of the article accidentally slipping out of the device during use, particularly after potential shrinkage of the article during use. The portion of the aerosol generating article configured to be inserted into the device is preferably longer than the portion of the aerosol generating article configured to protrude from the device when the aerosol generating article is received within the aerosol generating device.

[0321] The diameter of the device cavity may be approximately 4 mm to 10 mm. The diameter of the device cavity may be approximately 5 mm to 9 mm. The diameter of the device cavity may be approximately 6 mm to 8 mm. The diameter of the device cavity may be approximately 7 mm to 8 mm. The diameter of the device cavity may be approximately 7 mm to 7.5 mm.

[0322] 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.

[0323] 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 include 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 wall defining the device cavity and the aerosol generating article.

[0324] Such an airtight fit can establish an airtight fit or configuration between the device cavity and the aerosol-generating article received therein.

[0325] In such an airtight configuration, there is virtually no gap or empty space between the surrounding walls defining the device cavity and the aerosol-generating article through which air flows.

[0326] A tight fit with the aerosol-generating article can be established along the entire length of the device cavity, or along a portion of the length of the device cavity.

[0327] An aerosol generator may include an airflow channel 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 draws it out from the mouth end of the article.

[0328] The airflow channel of the aerosol generator may be defined within or by the peripheral wall of the housing of the aerosol generator. In other words, the airflow channel of the aerosol generator may be defined within the thickness of the peripheral wall, by the inner surface of the peripheral wall, or a combination of both. The airflow channel may be partially defined by the inner surface of the peripheral wall, or partially defined within the thickness of the peripheral wall. The inner surface of the peripheral wall defines the periphery of the device cavity.

[0329] 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.

[0330] The heater can be any suitable type of heater. In this invention, the heater is preferably an external heater.

[0331] When the heater is housed within the aerosol generator, it is preferable that it can heat the aerosol-generating article from the outside. Such an external heater can surround the aerosol-generating article when inserted into or received within the aerosol generator.

[0332] 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 into the cavity. The heater may be located within the apparatus cavity or heating chamber.

[0333] The heater may comprise at least one heating element. The at least one heating element can be any preferred 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.

[0334] 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 examples of metals include titanium, zirconium, tantalum, and platinum group metals. Suitable examples of 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.

[0335] 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).

[0336] In some embodiments, at least one heating element includes an electrically insulated substrate, and at least one resistance heating element is provided on the electrically insulated substrate.

[0337] 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.

[0338] 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. An electric current may pass through one or more conductive tracks to heat the heating element and the aerosol generating substrate.

[0339] In some embodiments, the heater comprises an induction heating arrangement. The induction heating arrangement 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 include 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 arranged to generate a high-frequency oscillating electromagnetic field within a 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.

[0340] 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.

[0341] The susceptor element may be positioned such that when an aerosol-generating article is received in 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 with a frequency of 1 to 30 MHz, for example 1 to 10 MHz, for example 5 to 7 MHz.

[0342] In these embodiments, the susceptor element is preferably located in contact with the aerosol-forming substrate. In some embodiments, the susceptor element is located within the aerosol generator. In these embodiments, the susceptor element may be located within a cavity. The aerosol generator may include only one susceptor element. The aerosol generator may comprise multiple susceptor elements. In some embodiments, the susceptor element is preferably positioned to heat the outer surface of the aerosol-forming substrate.

[0343] 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-forming 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 steel or stainless steel, ferromagnetic alloys, 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 about 20 percent, more preferably more than about 50 percent or more than 90 percent of ferromagnetic or paramagnetic material. Some elongated susceptor elements may be heated to temperatures above about 250 degrees Celsius.

[0344] A susceptor element may comprise a nonmetallic core having a metal layer arranged on a nonmetallic core. For example, a susceptor element may include a ceramic core or metal tracks formed on the outer surface of a substrate.

[0345] 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.

[0346] During use, the heater can be controlled to operate within a specified operating temperature range below the maximum operating temperature. The preferred operating temperature range within the heating chamber (or device cavity) is approximately 150°C to 300°C. The operating temperature range of the heater may be approximately 150°C to 250°C.

[0347] 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 a downstream section RTD of less than 15 mmH2O) and an aerosol generating device having an external heater with an operating temperature range of approximately 180°C to approximately 200°C, as described in this disclosure.

[0348] In embodiments in which the aerosol generating article has a ventilation zone located along a downstream section or a hollow tubular element, the ventilation zone may be positioned to be exposed when the aerosol generating article is housed 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.

[0349] When an article is received into the device cavity, the ventilation zone may be located at least 0.5 mm away from the opening end (or end face) of the device cavity or the device itself (in the downstream direction of the article). When an article is received into the device cavity, the ventilation zone may be located at least 1 mm away from the opening end (or end face) of the device cavity or the device itself (in the downstream direction of the article). When an article is received into the device cavity, the ventilation zone may be located at least 2 mm away from the opening end (or end face) of the device cavity or the device itself (in the downstream direction of the article).

[0350] 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 about 1.03 to about 1.13.

[0351] 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 of the article, making it reasonably possible for the ventilation zone to be blocked within the device cavity without being blocked.

[0352] 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 allow continuous heating of the aerosol generating substrate for approximately 6 minutes, or a multiple of 6 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 allow a predetermined number of puffs or discontinuous starts of the heater.

[0353] 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.

[0354] Example 1. An aerosol generating article comprising a rod of an aerosol generating substrate and a downstream section installed downstream of the rod of the aerosol generating substrate, the downstream section comprising at least one hollow tubular element.

[0355] Example 2. The aerosol generating article according to Example 1, further comprising an upstream section installed upstream of the rod of the aerosol generating substrate and comprising at least one upstream element.

[0356] Example 3. The aerosol generating article according to Example 2, wherein the upstream element has a length of 2 mm to 8 mm.

[0357] Example 4. An aerosol generating article according to Example 2 or 3, wherein the upstream element is formed from a hollow tubular segment defining a longitudinal cavity that provides an unrestricted flow channel.

[0358] Example 5. The aerosol-generating article according to Example 4, wherein the longitudinal cavity of the hollow tubular segment has a diameter of at least 5 millimeters.

[0359] Example 6. An aerosol generating article according to Example 4 or 5, wherein the hollow tubular segment has a wall thickness of less than 1 mm.

[0360] Example 7. An aerosol generating article according to any one of Examples 2 to 6, wherein the upstream element has a drawdown resistance (RTD) of less than 2 mmH2O.

[0361] Example 8. An aerosol generating article according to any one of Examples 2 to 7, wherein the upstream end of the upstream element defines the upstream end of the aerosol generating article.

[0362] Example 9. An aerosol-generating article according to any of the preceding examples, further comprising a ventilation zone.

[0363] Example 10. The aerosol-generating article according to Example 9, wherein the ventilation zone is provided along a hollow tubular element in the downstream section.

[0364] Example 11. An aerosol-generating article according to Example 9 or 10, wherein the ventilation zone is installed at a distance of 26 to 33 millimeters from the upstream end of the article.

[0365] Example 12. An aerosol-generating article according to Example 9 or 10, wherein the ventilation zone is installed at a distance of 27 to 31 millimeters from the upstream end of the article.

[0366] Example 13. An aerosol-generating article according to any of Examples 9 to 12, wherein the ventilation zone is installed at a distance of 12 to 20 millimeters from the downstream end of the article.

[0367] Example 14. An aerosol generating article according to any one of Examples 9 to 13, wherein the ventilation zone is installed at least 10 mm downstream of the downstream end of the rod of the aerosol generating substrate.

[0368] Example 15. An aerosol generating article according to any of the preceding examples, wherein the hollow tubular element in the downstream section has a length of 17 mm to 25 mm.

[0369] Example 16. An aerosol-generating article according to any of the preceding examples, wherein the hollow tubular element in the downstream section has an internal volume of at least 300 cubic millimeters.

[0370] Example 17. An aerosol generating article according to any of the preceding examples, wherein the rod of the aerosol generating substrate has a length of 8 mm to 16 mm.

[0371] Example 18. An aerosol generating article according to any of the preceding examples, wherein the rod of the aerosol generating substrate has a draw-to-draw (RTD) of 4 mmH2O to 10 mmH2O.

[0372] Example 19. The aerosol generating substrate is an aerosol generating article according to any of the preceding examples, comprising shredded tobacco material.

[0373] Example 20. The aerosol-generating article according to Example 19, wherein the shredded tobacco material has an average density of 150 milligrams to 500 milligrams per cubic centimeter.

[0374] Example 21. An aerosol generating article according to any of the preceding examples, wherein the aerosol generating substrate comprises one or more aerosol forming bodies, and the content of aerosol forming bodies in the aerosol generating substrate is 10% to 20% by weight on a dry weight basis.

[0375] Example 22. The aerosol generating article according to Example 19, wherein the aerosol forming body contains one or more of glycerin and propylene glycol.

[0376] Example 23. An aerosol generating article according to any of the preceding examples, wherein the aerosol generating substrate includes a tobacco cut filler.

[0377] Example 24. An aerosol generating article according to any of the preceding embodiments, wherein the downstream section further comprises a mouthpiece element.

[0378] Example 25. The aerosol generating article according to Example 24, wherein the mouthpiece element comprises at least one mouthpiece filter segment formed from a fibrous filtration material.

[0379] Example 26. The aerosol generating article according to Example 24 or 25, wherein the length of the mouthpiece element is 3 mm to 11 mm. Example 27. An aerosol generating article according to any one of Examples 24 to 26, wherein the mouthpiece element has a draw-to-discharge (RTD) of 4 mmH2O to 11 mmH2O.

[0380] Example 28. An aerosol generating article according to any of Examples 24 to 27, wherein the combined length of the hollow tubular element and mouthpiece element in the downstream section is 24 mm to 32 mm.

[0381] Example 29. An aerosol-generating article according to any of the preceding examples, wherein the article draw-out resistance (RTD) is 20 mmH2O to 22 mmH2O.

[0382] Example 30. An aerosol-generating article according to any of the preceding examples, wherein the outer diameter of the article is substantially uniform along its length.

[0383] Example 31. An aerosol-generating article according to any of the preceding examples, wherein the aerosol-generating article has an air permeability level of 10 percent to 30 percent.

[0384] Example 32. An aerosol-generating article according to any of the preceding examples, wherein the permeability level of the aerosol-generating article is 12 percent to 25 percent.

[0385] Example 33. An aerosol generating system comprising an aerosol generating article described in one of the prior embodiments, and an aerosol generating device comprising a heating chamber for receiving the aerosol generating article and at least a heating element installed around or near the heating chamber. [Brief explanation of the drawing]

[0386] The present invention will be further described below with reference to the attached drawings. [Figure 1] A schematic side perspective view of an aerosol-generating article according to one embodiment of the present invention is shown. [Figure 2] A schematic side cross-sectional view of an aerosol-generating article according to one embodiment of the present invention is shown. [Figure 3] A schematic cross-sectional view of an aerosol generating system comprising an aerosol generating article and an aerosol generating device according to one embodiment of the present invention is shown. [Modes for carrying out the invention]

[0387] The aerosol generating article 10 shown in Figure 1 comprises an aerosol generating base rod 12 and a downstream section 14 located downstream of the rod 12 of the aerosol generating base. Thus, the aerosol generating article 10 extends from an upstream or distal end 16 substantially coinciding with the upstream end of the rod 12 to a downstream or oral end 18 coinciding with the downstream end of the downstream section 14. The downstream section 14 comprises a hollow tubular element 20 and a mouthpiece element 50.

[0388] The aerosol-generating article 10 has an overall length of approximately 45 mm and an outer diameter of approximately 7.2 mm.

[0389] The aerosol generating substrate rod 12 contains shredded tobacco material. The aerosol generating substrate rod 12 contains 150 milligrams of shredded tobacco material containing 13 to 16 weight percent glycerin. The density of the aerosol generating substrate is approximately 300 mg per cubic centimeter. The RTD of the aerosol generating substrate rod 12 is approximately 6 to 8 mmH2O. The aerosol generating substrate rod 12 is individually wound with a plug wrap (not shown).

[0390] The hollow tubular element 20 is located immediately downstream of the rod 12 of the aerosol generating substrate, and the hollow tubular element 20 is longitudinally aligned with the rod 12. The upstream end of the hollow tubular element 20 abuts against the downstream end of the rod 12 of the aerosol generating substrate.

[0391] The hollow tubular element 20 defines the hollow section of the aerosol-generating article 10. The hollow tubular element does not substantially contribute to the overall RTD of the aerosol-generating article. More specifically, the RTD of the hollow tubular element 20 is approximately 0 mmH2O.

[0392] As shown in Figure 2, the hollow tubular element 20 is provided in the form of a hollow cylindrical tube made of cardboard. The hollow tubular element 20 defines an internal cavity 22 that extends all the way from the upstream end to the downstream end of the hollow tubular element 20. The internal cavity 22 is substantially empty and therefore allows for substantially unrestricted airflow along the internal cavity 22. The hollow tubular element 20 does not substantially contribute to the overall RTD of the aerosol generating article 10.

[0393] The hollow tubular element 20 has a length of approximately 21 millimeters, an outer diameter of approximately 7.2 millimeters, and an inner diameter of approximately 6.7 millimeters. Therefore, the thickness of the peripheral wall of the hollow tubular element 20 is approximately 0.25 millimeters.

[0394] The aerosol generating article 10 includes a ventilation zone 30 positioned along a hollow tubular element 20. More specifically, the ventilation zone 30 is located about 16 mm from the downstream end 18 of the article 10. The ventilation zone 30 is located about 12 mm downstream from the downstream end of the rod 12 of the aerosol generating substrate. The ventilation zone 30 is located about 9 mm upstream from the upstream end of the mouthpiece element 50. The ventilation zone 30 includes a circumferential row of openings or perforations surrounding the hollow tubular element 20. The perforations of the ventilation zone 30 extend through the walls of the hollow tubular element 20 to allow fluid to enter the internal cavity 22 from the outside of the article 10. The ventilation level of the aerosol generating article 10 is about 16 percent.

[0395] At the top of the rod 12 of the aerosol generating substrate and the downstream section 14 located downstream of the rod 12, the aerosol generating article 100 includes an upstream section 40 located upstream of the rod 12. Thus, the aerosol generating article 10 extends from a distal end 16 substantially coinciding with the upstream end of the upstream section 40 to a mouth end or downstream end 18 substantially coinciding with the downstream end of the downstream section 14.

[0396] The upstream section 40 comprises an upstream element 42 positioned immediately upstream of the rod 12 of the aerosol generating substrate, the upstream element 42 being longitudinally aligned with the rod 12. The downstream end of the upstream element 42 abuts against the upstream end of the rod 12 of the aerosol generating substrate. The upstream element 42 is provided in the form of a hollow cylindrical plug made of cellulose acetate tow, having a wall thickness of about 1 mm and defining an internal cavity 23. The upstream element 42 has a length of about 5 mm. The outer diameter of the upstream element 42 is about 7.1 mm. The inner diameter of the upstream element 42 is about 5.1 mm.

[0397] The mouthpiece element 50 extends from the downstream end of the hollow tubular element 20 to the downstream or oral end of the aerosol generating article 10. The mouthpiece element 50 has a length of approximately 7 mm. The outer diameter of the mouthpiece element 50 is approximately 7.2 mm. The mouthpiece element 50 comprises a low-density cellulose acetate filter segment. The RTD of the mouthpiece element 50 is approximately 8 mmH2O. The mouthpiece element 50 may be individually wrapped with a plug wrap (not shown).

[0398] As shown in Figures 1 and 2, article 10 comprises an upstream element 42, an aerosol generating substrate 12, and an upstream wrapper 44 surrounding a hollow tubular element 20. The ventilation zone 30 may also comprise a row of circumferential perforations located on the upstream wrapper 44. The perforations of the upstream wrapper 44 overlap with the perforations located on the hollow tubular element 20. As a result, the upstream wrapper 44 lies above the perforations of the ventilation zone 30 provided on the hollow tubular element 20.

[0399] Article 10 also includes a chipping wrapper 52 surrounding a hollow tubular element 20 and a mouthpiece element 50. The chipping wrapper 52 is located on the portion of the upstream wrapper 44 that is above the hollow tubular element 20. In this way, the chipping wrapper 52 effectively connects the mouthpiece element 50 to the rest of the components of Article 10. The width of the chipper wrapper 52 is approximately 26 mm. Furthermore, the ventilation zone 30 may include a row of circumferential perforations located on the chipping wrapper 52. The perforations of the chipping wrapper 52 overlap with the perforations provided on the hollow tubular element 20 and the upstream wrapper 44. As a result, the chipping wrapper 52 is located above the perforations of the ventilation zone 30 provided on the hollow tubular element 20 and the upstream wrapper 44.

[0400] Figure 3 illustrates an aerosol generating system 100, which includes an exemplary aerosol generator 1 and an aerosol generating article 10 equivalent to those shown in Figures 1 and 2. Figure 3 illustrates the downstream mouth end portion of the aerosol generator 1, where a device cavity is defined and capable of receiving the aerosol generating article 10. The aerosol generator 1 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.

[0401] 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.

[0402] 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 such power supply to the heater. The heater is configured to controllably heat the aerosol generating article 10 during use when the aerosol generating article 1 is received inside the device 1. The heater is preferably positioned to heat the aerosol generating substrate 12 from the outside for optimal aerosol generation. The ventilation zone 30 is positioned to be exposed when the aerosol generating article 10 is received inside the aerosol generator 1.

[0403] In the embodiment shown in Figure 3, the apparatus cavity defined by the peripheral wall 6 is 28 mm long. When the article 10 is received into the apparatus cavity, the upstream section 40, the rod 12 of the aerosol generating substrate, and the upstream portion of the hollow tubular element 20 are received into the apparatus cavity. This upstream portion of the hollow tubular element 20 is 11 mm long. As a result, approximately 28 mm of the article 10 is received inside the apparatus 1, and approximately 17 mm of the article 10 is located outside the apparatus 1. In other words, approximately 17 mm of the article 10 protrudes from the apparatus 1 when the article 10 is received inside it. This length PL of the article 10 protruding from the apparatus 1 is shown in Figure 3.

[0404] As a result, the ventilation zone 30 is advantageously located outside the apparatus 1 when the article 10 is inserted into the apparatus 1. If the apparatus cavity is 28 mm long, the ventilation zone 30 is located 1 mm downstream of the mouth end 2 of the apparatus 1 when the article 10 is received into the apparatus 1. 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 therein, which may or may not be specifically enumerated herein. Thus, in this context, number A is understood as A ± 10%. In this context, number A may be considered to include numbers that are within the general standard error to the measured value of the characteristic that number A modifies. In some cases, the figure A may deviate by the proportions listed above, provided that the amount of deviation of A does not substantially affect the basic and novel characteristics of the claimed invention. Furthermore, the entire range includes the disclosed maximum and minimum points and any intermediate ranges therebetween, which may or may not be specifically listed herein.

Claims

1. Aerosol-generating article, A rod of the aerosol generating substrate, A downstream section installed downstream of the rod of the aerosol generating substrate, the downstream section includes at least one hollow tubular element that abuts against the downstream end of the rod of the aerosol generating substrate, An upstream element installed upstream of the rod of the aerosol generating substrate and in contact with the upstream end of the rod of the aerosol generating substrate, wherein the upstream end of the upstream element defines the upstream end of the aerosol generating article, and the upstream element has a length of 3 mm to 7 mm. an aerosol generating article comprising a ventilation zone located along the hollow tubular element, wherein the distance between the ventilation zone and the upstream end of the upstream element is 26 mm to 33 mm.

2. The aerosol generating article according to claim 1, wherein the distance between the ventilation zone and the upstream end of the upstream element is 27 millimeters to 31 millimeters.

3. The aerosol generating article according to claim 1 or 2, wherein the rod of the aerosol generating substrate has a length of 8 mm to 16 mm.

4. The aerosol generating article according to any one of claims 1 to 3, wherein the hollow tubular element abuts against the upstream end of the mouthpiece element, and the total length of the hollow tubular element and the mouthpiece element is 24 mm to 32 mm.

5. The aerosol generating article according to any one of claims 1 to 4, wherein the upstream element includes a hollow tubular segment, and the hollow tubular segment has a central longitudinal cavity extending through it.

6. The aerosol generating article according to claim 5, wherein the hollow tubular segment of the upstream element has a wall thickness of 2 millimeters or less.

7. The aerosol generating article according to any one of claims 1 to 6, wherein the aerosol generating substrate comprises one or more aerosol forming bodies, and the content of the aerosol forming bodies in the aerosol generating substrate is at least 10% by weight on a dry weight basis.

8. The aerosol generating article according to claim 7, wherein the content of the aerosol-forming material in the aerosol-forming substrate is 20% by weight or less on a dry weight basis.

9. The aerosol generating article according to any one of claims 1 to 8, wherein the rod of the aerosol generating substrate has an RTD of 4 mmWG to 10 mmWG.

10. The aerosol generating article according to any one of claims 1 to 9, wherein the aerosol generating substrate includes shredded tobacco material.

11. The aerosol generating article according to claim 10, wherein the shredded tobacco material has a density of 150 milligrams per cubic centimeter to 500 milligrams per cubic centimeter.

12. The aerosol generating article according to any one of claims 1 to 11, wherein the aerosol generating article further includes a mouthpiece element at the downstream end of the aerosol generating article.

13. An aerosol generating system comprising an aerosol generating article according to any one of claims 1 to 12, and an aerosol generating device including a heating chamber for receiving the aerosol generating article and at least a heating element installed around or near the heating chamber.

14. The aerosol generating system according to claim 13, wherein the length of the heating chamber is 25 to 29 millimeters, and the distance between the ventilation zone and the upstream end of the upstream element exceeds the length of the heating chamber.

15. The aerosol generating system according to claim 13, wherein 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 1.03 to 1.13.

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