Aerosol generating article having a downstream section with low RTD

Abstract

An aerosol-generating article (10) is provided that includes a rod of aerosol-generating substrate (12). The aerosol-generating substrate includes one or more aerosol formers. The aerosol formers are present in an amount of 10 to 20 weight percent on a dry weight basis. The aerosol-generating article includes a mouthpiece element (50) located downstream of the rod of aerosol-generating substrate. The mouthpiece element includes at least one mouthpiece filter segment formed from a fibrous filtration material. The mouthpiece filter segment has a resistance to withdrawal of 4 mmH2O to 11 mmH2O. The aerosol-generating article also includes a hollow tubular element (20). The hollow tubular element is disposed between the rod of aerosol-generating substrate and the mouthpiece element. The combined length of the hollow tubular element and the mouthpiece element is 24 mm to 32 mm.

Description

Technical Field

[0001] The present invention relates to an aerosol-generating article comprising an aerosol-generating substrate and adapted to generate an inhalable aerosol upon heating. The present disclosure also relates to an aerosol-generating system comprising an aerosol-generating device and such an aerosol-generating article.

Background Art

[0002] Aerosol-generating articles in which an aerosol-generating substrate, such as a tobacco-containing substrate, is heated rather than burned are well 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 generators for consuming aerosol-generating articles. Such devices include, for example, electrically heated aerosol generators in which aerosols are generated by heat transfer from one or more electric heater elements of the aerosol generator to the aerosol-generating substrate of a heated aerosol-generating article. For example, electrically heated aerosol generators have been proposed that include internal heater blades adapted to be inserted into the aerosol-generating substrate. The use of aerosol-generating articles in combination with external heating systems is also known. For example, International Publication 2020 / 115151 describes the provision of one or more heating elements arranged around the periphery of an aerosol-generating article when the aerosol-generating article is received in a cavity of an aerosol generator. Alternatively, an inductively heated aerosol-generating article comprising an aerosol-generating substrate and a susceptor disposed within the aerosol-generating substrate is proposed in International Publication 2015 / 176898. [Overview of the project] [Problems that the invention aims to solve]

[0004] Aerosol-generating articles in which the tobacco-containing substrate is heated rather than burned present numerous challenges not seen in conventional smoking articles. Firstly, the tobacco-containing substrate is typically heated to significantly lower temperatures compared to the pre-combustion temperature in conventional cigarettes. This can affect nicotine release from the tobacco-containing substrate and nicotine delivery to the consumer. Simultaneously, if the heating temperature is increased in an attempt to enhance nicotine delivery, the generated aerosol typically needs to be cooled more to a greater extent and more rapidly before reaching the consumer. However, technical solutions commonly used in conventional smoking articles to cool the mainstream smoke, such as providing a highly filtration-efficient segment at the mouth-end of a cigarette, may have undesirable effects in aerosol-generating articles in which the tobacco-containing substrate is heated rather than burned, as they may reduce nicotine delivery. Consequently, it is desirable to provide novel aerosol-generating articles that can consistently ensure satisfactory aerosol delivery to the consumer.

[0005] Secondly, there is a general need for aerosol generating articles that are 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 heating cavity of an aerosol generator and at the same time be held securely within the heating cavity so as not to slip out during use.

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

[0007] This disclosure relates to an aerosol generating article. The aerosol generating article may comprise a rod of an aerosol generating substrate. The aerosol generating substrate may contain one or more aerosol forming bodies. The content of aerosol forming bodies in the aerosol generating substrate may be 10% to 20% by weight on a dry weight basis. The aerosol generating article may comprise a mouthpiece element located downstream of the rod of the aerosol generating substrate. The mouthpiece element may comprise at least one mouthpiece filter segment formed from a fibrous filter material. The draw resistance of the mouthpiece filter segment may be 4 mmH2O to 11 mmH2O. The aerosol generating article may comprise a hollow tubular element. The hollow tubular element may be provided between the rod of the aerosol generating substrate and the mouthpiece element. The combined length of the hollow tubular element and the mouthpiece element may be 24 mm to 32 mm. [Brief explanation of the drawing]

[0008] [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] This diagram shows a schematic side 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. [Modes for carrying out the invention]

[0009] The present invention provides an aerosol generating article comprising a rod of an aerosol generating substrate. The aerosol generating substrate comprises one or more aerosol forming bodies. The content of aerosol forming bodies in the aerosol generating substrate is 10% to 20% by weight on a dry weight basis. The aerosol generating article comprises a mouthpiece element located downstream of the rod of the aerosol generating substrate. The mouthpiece element comprises at least one mouthpiece filter segment formed from a fibrous filter material. The draw resistance of the mouthpiece filter segment is 4 mmH2O to 11 mmH2O. The aerosol generating article comprises a hollow tubular element. The hollow tubular element is provided between the rod of the aerosol generating substrate and the mouthpiece element. The combined length of the hollow tubular element and the mouthpiece element is 24 mm to 32 mm.

[0010] Furthermore, according to this disclosure, an aerosol generating system is provided comprising an aerosol generating article and an aerosol generating device as described above, wherein the aerosol generating device comprises a heating chamber for receiving the aerosol generating article and heating members disposed in or around the heating chamber.

[0011] The aerosol generating article according to the present invention provides an improved configuration that offers optimal aerosol generation while being of an appropriate length for the user to facilitate insertion into and removal from an aerosol generating device.

[0012] Providing a predefined, relatively large amount of aerosol-forming material within the rod of an aerosol-generating substrate can optimize aerosol generation, particularly in aerosol-generating articles configured to be heated within an aerosol generator. However, the presence of downstream components of the aerosol-generating substrate rod can hinder the aerosol droplets from moving downstream from the substrate as it heats and is withdrawn by the user. The length and structure of these downstream components can also play a role in absorbing or blocking these droplets.

[0013] Providing a relatively long downstream section with a hollow tubular element extends the beneficial cooling and nucleation phase of aerosols originating from a heated aerosol-generating substrate having a relatively high aerosol-forming content. However, both the time droplets spend in the relatively long hollow element and interference with the filtration material of the mouthpiece element can unfavorably affect the aerosolization advantages that provide the hollow tubular element and the relatively high aerosol-forming content. In the present invention, this is balanced by providing a mouthpiece (filtration) element having a relatively low RTD that reduces interference with the droplets as they progress through the mouthpiece filter toward the mouth end of the article.

[0014] Providing a mouthpiece element with a relatively low RTD also facilitates faster droplet propagation through the hollow element, as the user can create a larger pressure difference as a result of the relatively low RTD of the mouthpiece element and the entire downstream section.

[0015] Therefore, the selected aerosol-forming content, RTD of the mouthpiece element, and combined length of the hollow tubular element and mouthpiece element within the article according to the present invention provide a combination that enhances aerosol cooling and generation for the user, while improving the user experience by providing a relatively long downstream section that allows for easy insertion and removal from the aerosol generator.

[0016] 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 provided downstream of the aerosol generating substrate. One or more elements downstream of the rod of the aerosol generating substrate form the downstream section of the aerosol generating article. Additionally, the aerosol generating article according to the present invention may comprise elements provided 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.

[0017] As described above, the aerosol generating article according to the present invention comprises a rod of aerosol generating substrate. Preferably, the rod of the aerosol generating substrate is surrounded by a wrapper such as a plug wrap.

[0018] The rod of the aerosol generating substrate is preferably at least about 8 millimeters long. The rod of the aerosol generating substrate is preferably at least about 9 millimeters long. The rod of the aerosol generating substrate is more preferably at least about 10 millimeters long.

[0019] For example, the rod of the aerosol generating substrate preferably has a length of about 8 mm to about 16 mm, or about 9 mm to about 15 mm, or about 10 mm to about 14 mm. In one particularly preferred embodiment, the rod of the aerosol generating substrate has a length of about 12 mm.

[0020] The ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article is preferably at least about 0.15, more preferably at least about 0.2, and most preferably at least about 0.22.

[0021] The ratio of the length of the rod of the aerosol generating substrate to the total length of the aerosol generating article is preferably 0.35 or less, more preferably about 0.33 or less, and more preferably about 0.3 or less.

[0022] In a particularly preferred embodiment of 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 is approximately 0.25.

[0023] By adjusting the length of the rod of the aerosol generating substrate within any of the above ranges and by controlling the density of the aerosol generating substrate itself, the inventors have found that it is easier to better and more consistently control the overall RTD of the aerosol generating article. Further, since the length of the rod is also predefined, it is easier to ensure the desired positioning of the ventilation zone with respect to the substrate and the heating device during use.

[0024] The rod of the aerosol generating substrate preferably has an outer diameter substantially equal to the outer diameter of the aerosol generating article.

[0025] The "outer diameter of the rod of the aerosol generating substrate" may be calculated as the average of a plurality of measured values of the diameter of the rod of the aerosol generating substrate taken at different locations along the length of the rod of the aerosol generating substrate.

[0026] The rod of the aerosol generating substrate preferably has an outer diameter of at least about 5 millimeters. The rod of the aerosol generating substrate more preferably has an outer diameter of at least about 6 millimeters. The rod of the aerosol generating substrate even more preferably has an outer diameter of at least about 7 millimeters.

[0027] The rod of the aerosol generating substrate preferably has an outer diameter of about 12 millimeters or less. The rod of the aerosol generating substrate more preferably has an outer diameter of about 10 millimeters or less. The rod of the aerosol generating substrate even more preferably has an outer diameter of about 8 millimeters or less.

[0028] Generally, it has been observed that the smaller the diameter of the rod of an aerosol-generating substrate, the lower the temperature required to raise the core temperature of the rod so that a sufficient amount of vaporizable species is released from the aerosol-generating substrate to form a desired amount of aerosol. At the same time, although we do not wish to be bound by theory, it is understood that a smaller diameter of the rod of an aerosol-generating substrate allows the heat supplied to the aerosol-generating article to penetrate more quickly into the entire volume of the aerosol-forming substrate. Nevertheless, if the diameter of the rod of the aerosol-generating substrate is too small, the amount of available aerosol-forming substrate is reduced, so the volume-to-surface ratio of the aerosol-forming substrate becomes less favorable.

[0029] The diameter of the aerosol generating substrate rods within the range described herein is particularly advantageous in terms of the balance between energy consumption and aerosol delivery. This advantage is especially noticeable when an aerosol generating article having an aerosol generating substrate rod having the diameter described herein is used in combination with an external heater positioned around the aerosol generating article. Under these operating conditions, it has been observed that less thermal energy is required to achieve a sufficiently high temperature at the core of the aerosol generating substrate rod, and generally at the core of the article. Therefore, when operating at lower temperatures, the desired target temperature at the core of the aerosol generating substrate may be achieved within a desirablely reduced time frame and with less energy consumption.

[0030] 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.

[0031] In a particularly preferred embodiment, the rod of the aerosol generating substrate has an outer diameter of less than about 7.5 millimeters. For example, the rod of the aerosol generating substrate may have an outer diameter of about 7.2 millimeters.

[0032] The ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article may be at least about 0.10. Preferably, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is at least about 0.15. More preferably, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is at least about 0.20. Even more preferably, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is at least about 0.25.

[0033] Generally, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article may be about 0.60 or less. Preferably, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is about 0.50 or less. More preferably, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is about 0.45 or less. Even more preferably, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is about 0.40 or less. In a particularly preferred embodiment, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is about 0.35 or less, and most preferably 0.30 or less.

[0034] In some embodiments, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is about 0.10 to about 0.45, preferably about 0.15 to about 0.45, more preferably about 0.20 to about 0.45, and still more preferably about 0.25 to about 0.45. In other embodiments, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is 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 still more preferably about 0.25 to about 0.40. In further embodiments, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is 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 still more preferably about 0.25 to about 0.35. In further embodiments, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is 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.

[0035] 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.

[0036] In the aerosol generating article according to the present invention, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article may be about 0.60 or less. Preferably, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article may be about 0.50 or less. More preferably, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article may be about 0.40 or less. Even more preferably, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article may be about 0.30 or less.

[0037] In the aerosol generating article according to the present invention, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article may be at least about 0.10. Preferably, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article may be at least about 0.15. More preferably, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article may be at least about 0.20. In a particularly preferred embodiment, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article may be at least about 0.25.

[0038] In some embodiments, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is 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 still more preferably about 0.25 to about 0.60. In other embodiments, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is 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 still more preferably about 0.25 to about 0.50. In further embodiments, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article is 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 still more preferably about 0.25 to about 0.40. For example, the ratio between the length of the rod of the aerosol generating substrate and the total length of the aerosol generating article may be about 0.25 to about 0.30, and is preferably about 0.27.

[0039] The density of the aerosol generating substrate is preferably at least about 150 mg 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.

[0040] Preferably, the density of the aerosol generating substrate is about 500 mg / cubic centimeter or less. More preferably, the density of the aerosol generating substrate is about 450 mg / cubic centimeter or less. More preferably, the density of the aerosol generating substrate is about 400 mg / cubic centimeter or less. Even more preferably, the density of the aerosol generating substrate is about 350 mg / cubic centimeter or less.

[0041] For example, the density of the aerosol generating substrate is preferably about 150 mg per cubic centimeter to about 500 mg per cubic centimeter, preferably about 175 mg per cubic centimeter to about 450 mg per cubic centimeter, more preferably about 200 mg per cubic centimeter to about 400 mg per cubic centimeter, and even more preferably about 250 mg per cubic centimeter to about 350 mg per cubic centimeter. In one particularly preferred embodiment of the present invention, the density of the aerosol generating substrate is about 300 mg per cubic centimeter.

[0042] In a particular preferred embodiment, the rod of the aerosol generating substrate comprises shredded tobacco material (e.g., tobacco cut filler) and has a density of about 150 mg per cubic centimeter to about 500 mg per cubic centimeter, preferably about 175 mg per cubic centimeter to about 450 mg per cubic centimeter, more preferably about 200 mg per cubic centimeter to about 400 mg per cubic centimeter, more preferably about 250 mg per cubic centimeter to about 350 mg per cubic centimeter, and most preferably about 300 mg per cubic centimeter.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] The aerosol generating substrate may be a solid aerosol generating substrate. Preferably, the aerosol generating substrate includes an aerosol forming element. The aerosol forming element may be any suitable well-known compound or mixture of compounds that facilitates the formation of a high-density, stable aerosol during use. The aerosol forming element may facilitate the aerosol being substantially resistant to thermal decomposition at the temperatures typically applied during use of the aerosol generating article. Suitable aerosol forming elements include, for example, polyhydric alcohols (e.g., triethylene glycol, 1,3-butanediol, propylene glycol, glycerin, etc.), esters of polyhydric alcohols (e.g., glycerol mono-, di-, or triacetate, etc.), aliphatic esters of mono-, di-, or polycarboxylic acids (e.g., dimethyl dodecanediol, dimethyl tetradecanediol, etc.), and combinations thereof.

[0047] The aerosol-forming body preferably contains one or more of glycerin and propylene glycol. The aerosol-forming body may consist of glycerin, propylene glycol, or a combination of glycerin and propylene glycol.

[0048] The aerosol generating substrate preferably contains at least 5% by weight of aerosol forming material on a dry weight basis of the aerosol generating substrate, more preferably 10% to 22% by weight of aerosol forming material on a dry weight basis of the cut aerosol generating substrate, more preferably the amount of aerosol forming material is 12% to 19% by weight basis of the dry weight of the aerosol generating substrate, and most preferably the amount of aerosol forming material is 13% to 16% by weight basis of the dry weight of the aerosol generating substrate.

[0049] 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 finely cut sheets of homogenized tobacco material. Suitable homogenized tobacco materials for use in the present invention are described below.

[0050] In the context of this specification, the term “cut filler” is used to describe a blend of finely chopped plant materials, such as tobacco plant material, which specifically includes one or more of the following: leaf blades, processed stems and veins, and homogenized plant material.

[0051] Cut fillers may also include other cut pieces, filler tobacco, or outer covering.

[0052] 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. The plant material is preferably one of tobacco, mint, tea, or clove. The plant material is most preferably tobacco. However, as will be discussed in more detail below, the present invention is equally applicable to other plant materials having the ability to release a substance that can subsequently form an aerosol upon application of heat.

[0053] The cut filler preferably contains tobacco plant material, including one or more leaf blades from bright tobacco, dark tobacco, aromatic tobacco, and filler tobacco. In relation to the present invention, the term "tobacco" refers to any plant of the genus Nicotiana.

[0054] Bright tobacco is tobacco that generally has 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 flavor. In the context of this invention, bright tobacco is tobacco having a reducing sugar content of about 2.5 percent to about 20 percent on a dry weight basis of the leaves, and a total ammonia content of 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.

[0055] 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, snuff, cigars, and pipe blends also falls into this category. Typically, these dark tobaccos are air-cured and, in some cases, fermented. From a sensory perspective, dark tobacco is a type of tobacco that, after curing, has a smoky, dark cigar-like character. 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 by dry weight of the leaves and the total ammonia content is less than about 0.5 percent by dry weight of the leaves.

[0056] Aromatic tobacco is tobacco that often has small, light-colored leaves. Throughout this specification, the term “aromatic tobacco” is used in reference to other tobaccos with a high content of aromatic compounds, such as essential oils. From a sensory perspective, aromatic tobacco is a type of tobacco that, after curing, has a spicy and aromatic sensation. Examples of aromatic tobaccos include Greek Orient, Oriental Turkish, and Semi-Oriental tobaccos, but also US Burley, Rustica, or Maryland, such as Fire-Cured Perique. Filler tobacco is not a specific type of tobacco, but includes tobacco types that are primarily used to complement other tobacco types used in blends and do not impart a specific characteristic aromatic direction to the final product. Examples of filler tobacco are the stems, midribs, or petioles of other tobacco types. A specific example may be the fully cured stems of the lower petioles of Full-Cured Brazil.

[0057] 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 entire aerosol generating substrate.

[0058] Since the length of the strand depends on the overall size of the object from which the strand is cut, the strand length of the cut filler is a somewhat random value. Nevertheless, longer strands can be cut by conditioning the material before cutting, for example by controlling the moisture content and overall delicacy of the material. Preferably, the strands have a length of about 10 mm to about 40 mm, and then the strands are arranged to form a rod of aerosol generating substrate. Of course, if the strands are arranged in the rod of the aerosol generating substrate with a longitudinal extension of the section that is less than 40 mm, the final rod of the aerosol generating substrate may contain strands that are, on average, shorter than the initial strand length. Preferably, the strand length of the cut filler is such that about 20 percent to 60 percent of the strand extends along the entire length of the rod of the aerosol generating substrate. This prevents the strand from easily coming off the rod of the aerosol generating substrate.

[0059] 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 typically allows for sufficient material for aerosol formation. Additionally, in light of the aforementioned constraints on diameter and size, this allows for a balanced density of the rod of the aerosol-generating substrate between energy uptake, draw resistance, and fluid passages within the rod of the aerosol-generating substrate, when the aerosol-generating substrate contains plant material.

[0060] The cut filler is preferably immersed in an aerosol-forming agent. Immersion of the cut filler can be carried out by spraying or by other suitable application methods. The aerosol-forming agent may be applied to the blend during the preparation of the cut filler. For example, the aerosol-forming agent may be applied directly to the blend in the conditioning casing cylinder (DCCC). Conventional machinery can be used to apply the aerosol-forming agent to the cut filler. The aerosol-forming agent may be any suitable well-known compound or mixture of compounds that facilitates the formation of a high-density, stable aerosol during use. The aerosol-forming agent may facilitate 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.

[0061] The aerosol-forming body preferably contains one or more of glycerin and propylene glycol. The aerosol-forming body may consist of glycerin, propylene glycol, or a combination of glycerin and propylene glycol.

[0062] Preferably, the amount of aerosol-forming material is at least 5% by weight on a dry weight basis, preferably 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 not only to the surrounding cut filler particles but also to the surrounding surface (e.g., the inner surface of the wrapper surrounding the cut filler), thus helping to hold the cut filler in place within the article.

[0063] In some embodiments, the amount of aerosol former has a target value of about 13 weight percent on a dry weight basis of the cut filler. The most efficient amount of aerosol former also depends on the cut filler, and whether the cut filler contains plant leaf blades or homogenized plant material. For example, among other factors, the type of cut filler determines to what extent the aerosol former can facilitate the release of material from the cut filler.

[0064] For these reasons, a rod of an aerosol generating substrate equipped with the cut filler described above has the ability to efficiently generate a sufficient amount of aerosol at relatively low temperatures. A temperature of 150 to 200 degrees Celsius in the heating chamber may be sufficient for one such cut filler to generate a sufficient amount of aerosol, while a temperature of approximately 250 degrees Celsius is typically employed in aerosol generators using tobacco cast leaf sheets.

[0065] A further advantage associated with operating at lower temperatures is the reduced need to cool the aerosol. Since generally lower temperatures are used, simpler cooling mechanisms may suffice. This, in turn, allows for the use of simpler and more streamlined structures in aerosol-generating articles.

[0066] In other preferred embodiments, the aerosol-generating substrate includes homogenized plant material, preferably homogenized tobacco material.

[0067] 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 with particles of tobacco material obtained by optionally grinding, pulverizing, or finely crushing one or more of tobacco leaf laminas and tobacco leaf stems. The homogenized plant material may be produced by casting, extrusion, papermaking processes, or any other suitable process known in the art.

[0068] Homogenized plant material can be provided in any suitable form.

[0069] 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.

[0070] The homogenized plant material may be in the form of multiple pellets or granules.

[0071] Homogenized plant material may be in the form of multiple strands, strips, or fragments. As used herein, the term “strand” describes an elongated element of the material having a length substantially greater than its width and thickness. The term “strand” should be understood to encompass any other homogenized plant material having strips, fragments, or similar forms. Strands of homogenized plant material may be formed from a sheet of homogenized plant material, for example, by cutting or dicing, or by other means, such as by extrusion.

[0072] In some embodiments, strands may form 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 one another. Alternatively, each strand of homogenized plant material within the aerosol-generating substrate may be at least partially connected to an adjacent strand(s) 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 due to splitting of a sheet of homogenized plant material during the manufacture of the aerosol-generating substrate, as described above.

[0073] As described above, if the homogenized plant material is in the form of one or more sheets, the sheets may be manufactured by a casting process. Alternatively, the sheets of homogenized plant material may be manufactured by a papermaking process.

[0074] Each of the one or more sheets described herein may individually have a thickness of 100 to 600 micrometers, preferably 150 to 300 micrometers, and most preferably 200 to 250 micrometers. Individual thickness refers to the thickness of an individual sheet, while combined thickness refers to the total thickness of all sheets constituting the aerosol generating substrate. For example, if the aerosol generating substrate is formed from two individual sheets, the combined thickness is the thickness of the two individual sheets, or the sum of the measured thicknesses of the two sheets, which are stacked within the aerosol generating substrate.

[0075] Each of the sheets described herein may individually have a basis weight of approximately 100 grams per square meter to approximately 600 grams per square meter.

[0076] Each of the sheets described herein may individually have a density of about 0.3 grams per cubic centimeter to about 1.3 grams per cubic centimeter, preferably about 0.7 grams per cubic centimeter to about 1.0 gram per cubic centimeter.

[0077] 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.

[0078] One or more sheets of homogenized plant material may be assembled transversely to their longitudinal axis and surrounded by a wrapper to form a continuous rod or plug.

[0079] One or more sheets of homogenized plant material may, advantageously, be crimped or similarly treated. As used herein, the term “crimped” means a sheet having multiple substantially parallel ridges or undulations. One or more sheets of homogenized plant material may be embossed, debossed, perforated, or otherwise deformed to provide texture on one or both sides of the sheet.

[0080] Preferably, each sheet of homogenized plant material may be crimped to have multiple ridges or undulations substantially parallel to the cylindrical axis of the plug. This process advantageously facilitates assembling the crimped sheets of homogenized plant material to form the plug. Preferably, one or more sheets of homogenized plant material may be assembled. Naturally, the crimped sheets of homogenized plant material may, in other ways or additionally, have multiple substantially parallel ridges or undulations positioned at acute or obtuse angles with respect to the cylindrical axis of the plug. The sheets may be crimped to such an extent that the integrity of the sheet is interfered with by the multiple parallel ridges or undulations, causing separation of the material and resulting in the formation of fragments, strands, or shards of homogenized plant material.

[0081] Alternatively, one or more sheets of homogenized plant material may be cut into strands as described above. In such embodiments, the aerosol-generating substrate comprises several strands of homogenized plant material. The strands may be used to form a plug. Typically, the width of such strands is about 5 millimeters, or about 4 millimeters, or about 3 millimeters, or about 2 millimeters, or less. The length of the strands may be longer than about 5 millimeters, or about 5 millimeters to about 15 millimeters, or about 8 millimeters to about 12 millimeters, or about 12 millimeters. Preferably, the strands are substantially the same length as each other.

[0082] 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 up to about 80 weight percent of plant particles, more preferably up to about 70 weight percent of plant particles, more preferably up to about 60 weight percent of plant particles, and more preferably up to about 50 weight percent of plant particles.

[0083] 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.

[0084] In certain embodiments of the present invention, the homogenized plant material is a homogenized tobacco material containing tobacco particles. The sheets of homogenized tobacco material used in these embodiments of the present invention may have a tobacco content of at least about 40 weight percent, more preferably at least about 50 weight percent, more preferably at least about 70 weight percent, and most preferably at least about 90 weight percent, on a dry weight basis.

[0085] In relation to the present invention, the term “tobacco particles” describes particles of any plant of the genus Nicotiana. The term “tobacco particles” includes crushed or powdered tobacco leaf blades, crushed or powdered tobacco leaf stems, tobacco dust, tobacco fines, and other particulate tobacco by-products formed during the processing, handling, and shipping of tobacco. In one preferred embodiment, the 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.

[0086] The homogenized plant material may further contain one or more aerosol-forming bodies. Upon volatilization, the aerosol-forming bodies can transport other vaporized compounds (such as nicotine and flavorings) released from the aerosol-generating substrate upon heating in the aerosol. Suitable aerosol-forming bodies for inclusion in the homogenized plant material are known in the art and include, but are not limited to, polyhydric alcohols (such as triethylene glycol, propylene glycol, 1,3-butanediol, and glycerol), esters of polyhydric alcohols (such as glycerol mono-, di-, or triacetate), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanediate and dimethyl tetradecanediate).

[0087] The homogenized plant material may contain an aerosol-forming agent content of approximately 5% to 30% by weight on a dry weight basis (e.g., approximately 10% to 25% by weight on a dry weight basis, or approximately 15% to 20% by weight on a dry weight basis). The aerosol-forming agent may act as a wetting agent in the homogenized plant material.

[0088] As shown above, the rod of the aerosol generating substrate may be surrounded by a wrapper. The wrapper surrounding the rod 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 industry and include, but are not limited to, cigarette paper and filter plug wrappers. Suitable non-paper wrappers for use in specific embodiments of the present invention are known in the industry and include, but are not limited to, sheets of homogenized tobacco material.

[0089] 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 55 micrometers or less, preferably 50 micrometers or less, more preferably 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.

[0090] In certain preferred embodiments, the wrapper may be formed from a laminated material comprising multiple layers. Preferably, the wrapper is formed from an aluminum co-laminate sheet. The use of an aluminum co-laminate sheet is advantageous in that it prevents combustion of the aerosol-generating substrate when the aerosol-generating substrate is to be ignited rather than heated in the intended manner.

[0091] The paper layer of the co-laminated sheet may have a basis weight of at least 35 gsm, preferably at least 40 gsm. The paper layer of the co-laminated sheet may have a basis weight of 55 gsm or less, preferably 50 gsm or less. The paper layer of the co-laminated sheet may have a basis weight of 35 gsm to 55 gsm, preferably 40 gsm to 50 gsm. In one preferred embodiment, the paper layer of the co-laminated sheet may have a basis weight of 45 gsm.

[0092] The paper layer of the co-laminated sheet may have a thickness of at least 50 micrometers, preferably at least 55 micrometers, and more preferably at least 60 micrometers. The paper layer of the co-laminated sheet may have a thickness of 80 micrometers or less, preferably 75 micrometers or less, and more preferably 70 micrometers or less.

[0093] The paper layer of the co-laminated sheet may have a thickness of about 50 micrometers to about 80 micrometers, preferably about 55 micrometers to about 75 micrometers, and more preferably about 60 micrometers to about 70 micrometers. In one preferred embodiment, the paper layer of the co-laminated sheet may have a thickness of 65 microns.

[0094] The metal layer of the co-laminated sheet may have a basis weight of at least 12 gsm, preferably at least 15 gsm. The metal layer of the co-laminated sheet may have a basis weight of 25 gsm or less, preferably 20 gsm or less. The metal layer of the co-laminated sheet may have a basis weight of 12 gsm to 25 gsm, preferably 15 gsm to 20 gsm. In one preferred embodiment, the metal layer of the co-laminated sheet may have a basis weight of 17 gsm.

[0095] 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.

[0096] The metal layer of the co-laminated sheet may have a thickness of about 2 micrometers to about 15 micrometers, preferably about 3 micrometers to about 12 micrometers, and more preferably about 5 micrometers to about 10 micrometers. In one preferred embodiment, the metal layer of the co-laminated sheet may have a thickness of 6 microns.

[0097] 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.

[0098] PVOH or silicon is applied to the paper layer as a surface coating, such as by placing it on the outer surface of the paper layer of the wrapper surrounding the rod of the aerosol generating substrate. PVOH or silicon may be placed on the outer surface of the paper layer of the wrapper, forming a layer. PVOH or silicon may be placed on the inner surface of the paper layer of the wrapper. PVOH or silicon may be placed on the inner surface of the paper layer of the aerosol generating article, forming a layer. PVOH or silicon may be placed on both the inner and outer surfaces of the paper layer of the wrapper. PVOH or silicon may be placed on both the inner and outer surfaces of the paper layer of the wrapper, forming a layer.

[0099] 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, preferably 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.

[0100] The 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. The 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. The 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, the paper wrapper containing PVOH or silicon may have a thickness of 37 micrometers.

[0101] The wrapper surrounding the rod of the aerosol-generating substrate may include a flame-retardant composition comprising one or more flame-retardant compounds. The term “flame-retardant compound” is used herein to describe compounds that, when added to or otherwise incorporated into a carrier substrate such as paper or a plastic compound, provide varying degrees of flammability protection to the carrier substrate. In practice, flame-retardant compounds may be activated by the presence of an ignition source and may also be adapted to prevent or slow further progression of ignition through a variety of different physical and chemical mechanisms.

[0102] A flame-retardant composition may typically further contain one or more non-flammable compounds (solvents, excipients, fillers, etc.) that do not actively contribute to providing flammability protection to the carrier substrate, but are used to facilitate the application of the flame-retardant compound(s) to, or in, the wrapper. Some of the non-flammable compounds (solvents, etc.) in the flame-retardant composition are volatile and may evaporate from the wrapper as it dries after the flame-retardant composition has been applied to, or in, or in, the wrapping substrate. Thus, although these non-flammable compounds form part of the formulation of the flame-retardant composition, they may no longer be present in, or only detectable in trace amounts, within the wrapper of the aerosol-generating article.

[0103] Numerous suitable flame retardant compounds are known to those skilled in the art. Specifically, several flame retardant compounds and formulations suitable for treating cellulosic materials are known and disclosed and may be found to be used in the manufacture of wrappers for aerosol-generating articles according to the present invention.

[0104] For example, a flame retardant composition may comprise a polymer and a mixed salt based on at least one mono, di, and / or tricarboxylic acid, at least one polyphosphate, pyrophosphate, and / or phosphoric acid, and a hydroxide or alkali or alkaline earth metal salt, wherein at least one mono, di, and / or tricarboxylic acid and the hydroxide or salt form a carboxylate and at least one polyphosphate, and the pyrophosphate and / or phosphoric acid and the hydroxide or salt form a phosphate. Preferably, the flame retardant composition may further comprise an alkali or alkaline earth metal carbonate. Alternatively, the flame retardant composition may comprise at least one C10 or higher fatty acid, tall oil fatty acid (TOFA), phosphorylated linseed oil, or cellulose modified with phosphorylated downstream corn oil. Preferably, at least one C10 or higher fatty acid is selected from the group consisting of capric acid, myristic acid, palmitic acid, and combinations thereof.

[0105] In a wrapper comprising a flame retardant composition suitable for use in an aerosol-generating article according to the present invention, the flame retardant composition may be provided within a treated portion of the wrapper. This means that the flame retardant composition is applied on or within a corresponding portion of the wrapping substrate of the wrapper, or both on and within this portion. Therefore, 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 to 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 of the outer surface area of ​​the rods of the aerosol-generating substrate surrounded by the wrapper, more preferably at least about 40 percent of the outer surface area of ​​the rods of the aerosol-generating substrate, and even more preferably at least about 60 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 to 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 to at least about 90 percent or even 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.

[0106] 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.

[0107] 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.

[0108] The aerosol-generating article according to this disclosure preferably comprises an upstream section located upstream of the rod of the aerosol-generating substrate. The upstream section is preferably located immediately upstream of the rod of the aerosol-generating substrate. The upstream section preferably extends between the upstream end of the aerosol-generating article and the rod of the aerosol-generating substrate. The upstream section may comprise one or more upstream elements located upstream of the rod of the aerosol-generating substrate. Such one or more upstream elements are described in this disclosure.

[0109] The aerosol-generating article of the present invention preferably comprises an upstream element located upstream of and adjacent to the aerosol-generating substrate. The upstream element advantageously prevents direct physical contact with the upstream end of the aerosol-generating substrate. For example, if the aerosol-generating substrate comprises a susceptor element, the upstream element may prevent direct physical contact with the upstream end of the susceptor element. This helps prevent displacement or deformation of the susceptor element during handling or transport of the aerosol-generating article. As a result, this helps to fix the shape and position of the susceptor element. Furthermore, the presence of the upstream element helps to prevent any loss of the substrate, which may be advantageous, for example, if the substrate contains particulate plant material.

[0110] If the aerosol-generating substrate contains shredded tobacco, such as tobacco cut filler, the upstream section or its components may additionally help prevent the loss of loose tobacco particles from the upstream end of the article.

[0111] The upstream section or its upstream element may also provide some degree of additional protection to the aerosol-generating substrate during storage, by covering at least to some extent the upstream end of the aerosol-generating substrate which may otherwise be exposed.

[0112] In the case of an aerosol generating article intended to be inserted into a cavity within an aerosol generating device so that the aerosol generating substrate can be externally heated within the cavity, the upstream section or its upstream element may advantageously facilitate the insertion of the upstream end of the article into the cavity. Including the upstream element may provide additional protection to the ends of the rods of the aerosol generating substrate during insertion of the article into the cavity, thereby minimizing the risk of damage to the substrate.

[0113] The upstream section or its upstream element may also provide an improved appearance to the upstream end of the aerosol-generating article. Furthermore, where desired, the upstream section or its upstream element may be used to provide information about the aerosol-generating article, such as information about the brand, flavor, contents, or details of the aerosol generator with which the article is intended to be used.

[0114] 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 porosity of the upstream element in the longitudinal direction is defined by the ratio of the cross-sectional area of ​​the material forming the upstream element to the internal cross-sectional area of ​​the aerosol-generating article at the location of the upstream element.

[0115] The upstream element may be made of a porous material or may have multiple openings. This may be achieved, for example, by laser drilling. Preferably, the multiple openings are uniformly distributed across the cross-section of the upstream element.

[0116] The porosity or permeability of the upstream element may be advantageously designed to provide an aerosol-generating article having a specific overall drawdown resistance (RTD) that does not substantially affect the filtration provided by the other parts of the article.

[0117] The upstream element may be formed from a material that is impermeable to air. In such embodiments, the aerosol generating article may be configured so that air flows into the rods of the aerosol generating substrate through appropriate ventilation means provided within the wrapper.

[0118] In certain preferred embodiments of the present invention, it may be desirable to minimize the RTD of upstream elements. For example, this may be the case for articles intended to be inserted into a cavity of an aerosol generator so that the aerosol generating substrate is heated from the outside, as described herein. In such articles, it is desirable to provide the article with the lowest possible RTD so that the majority of the consumer's RTD experience is provided by the aerosol generator rather than the article itself.

[0119] The RTD of the upstream element is preferably about 10 mmH2O or less. The RTD of the upstream element is more preferably about 5 mmH2O or less. The RTD of the upstream element is even more preferably about 2.5 mmH2O or less. The RTD of the upstream element is even more preferably about 2 mmH2O or less.

[0120] 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.

[0121] In some embodiments, the RTD of the upstream element rod is about 0.1 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 upstream element rod is about 0.1 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 further embodiments, the RTD of the upstream element rod 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 a further embodiment, the RTD of the upstream element rod 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 a particularly preferred embodiment, the RTD of the upstream element is about 1 mmH2O.

[0122] The upstream element preferably has an RTD of less than about 2 mm of H2O per millimeter, more preferably less than about 1.5 mm of H2O per millimeter, more preferably less than about 1 mm of H2O per millimeter, more preferably less than about 0.5 mm of H2O per millimeter, more preferably less than about 0.3 mm of H2O per millimeter, and more preferably less than about 0.2 mm of H2O per millimeter.

[0123] Preferably, the RTD, which is a combination of the upstream section or its upstream element and the rod of the aerosol generating substrate, has an RTD of less than about 15 mmH2O, more preferably less than about 12 mmH2O, and more preferably less than about 10 mmH2O.

[0124] In a particularly preferred embodiment, the upstream element is formed from a hollow tubular segment defining a longitudinal cavity that provides an unrestricted flow channel. In such embodiments, the upstream element can provide protection from the aerosol-generating substrate as described above, while having minimal effect on the overall draw-to-discharge (RTD) and filtration characteristics of the article.

[0125] Preferably, the diameter of the cavity in the longitudinal direction 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. The diameter of the cavity in the longitudinal direction is preferably 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.

[0126] 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.

[0127] The upstream element of the upstream section may be made of any material suitable for use in an aerosol generating article. The upstream element may be made of the same material 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 element include filter material, ceramic, polymer material, cellulose acetate, cardboard, zeolite, or aerosol generating substrate. The upstream element may comprise a cellulose acetate plug. The upstream element may comprise a hollow acetate tube or a cardboard tube.

[0128] The upstream element is preferably made of a heat-resistant material. For example, the upstream element is preferably made of a material that can withstand temperatures up to 350 degrees Celsius. This ensures that the upstream element is not adversely affected by the heating means used to heat the aerosol generating substrate.

[0129] The upstream section or its upstream element preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article. Preferably, the outer diameter of the upstream section or its upstream element is about 6 mm to about 8 mm, and more preferably about 7 mm to about 7.5 mm. The upstream section or its upstream element preferably has an outer diameter of about 7.1 mm.

[0130] 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 one particularly preferred embodiment, the upstream section or upstream element has a length of about 5 mm. Advantageously, the length of the upstream section or upstream element can be varied to provide a desired overall length of the aerosol-generating article. For example, if it is desirable to reduce the length of one of the other components of the aerosol-generating article, the length of the upstream section or upstream element may be increased to maintain the same overall length of the article.

[0131] In addition, for articles intended to be externally heated, the length of the upstream section or its upstream element can be used to control the position of the aerosol-generating article within the cavity of the aerosol generator. This is advantageous because it ensures that the position of the aerosol-generating substrate within the cavity can be optimized for heating, as well as the position of any ventilation.

[0132] The upstream section is preferably surrounded by a wrapper such as a plug wrap. The wrapper surrounding the upstream section is preferably a rigid plug wrap, for example, a plug wrap having a basis weight of at least about 80 grams per square meter (gsm), or at least about 100 gsm, or at least about 110 gsm. This provides structural rigidity to the upstream section.

[0133] The upstream section is preferably connected by an outer wrapper to the rod of the aerosol generating substrate and optionally to at least a portion of the downstream section, as described herein.

[0134] As described above, the aerosol generating article according to the present invention comprises a downstream section located downstream of the rod of the aerosol generating substrate. Preferably, the downstream section is located immediately downstream of the rod of the aerosol generating substrate. Preferably, the downstream section of the aerosol generating article extends between the rod of the aerosol generating substrate and the downstream end of the aerosol generating article. The downstream section may comprise one or more elements, each of which is described in more detail in this disclosure.

[0135] The length of the downstream section may be at least about 20 millimeters. The length of the downstream section may be at least about 24 millimeters. The length of the downstream section may be at least about 26 millimeters.

[0136] The length of the downstream section may be approximately 36 mm or less (in other words, not exceeding approximately 36 mm). 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.

[0137] 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.

[0138] The downstream section preferably comprises a hollow tubular element. The downstream section preferably comprises a mouthpiece element. In a preferred embodiment of the present invention, the downstream section comprises 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.

[0139] In embodiments where the downstream section comprises a hollow tubular element and a mouthpiece element, the combined length or overall length of the hollow tubular element and the mouthpiece element may be at least about 20 mm. In other words, the sum of the lengths of the hollow tubular element and the mouthpiece element may be at least about 20 mm. The combined length of the hollow tubular element and the mouthpiece element may be at least about 24 mm. The combined length of the hollow tubular element and the mouthpiece element may be at least about 26 mm.

[0140] The combined length of the hollow tubular element and mouthpiece element may be approximately 36 mm or less. The combined length of the hollow tubular element and mouthpiece element may be approximately 32 mm or less. The combined length of the hollow tubular element and mouthpiece element may be approximately 30 mm or less.

[0141] The combined length of the hollow tubular element and mouthpiece element may be approximately 20 mm to 36 mm. The combined length of the hollow tubular element and mouthpiece element may be approximately 24 mm to 32 mm. The combined length of the hollow tubular element and mouthpiece element may be approximately 26 mm to 30 mm.

[0142] Preferably, the combined length of the hollow tubular element and the mouthpiece element may be about 28 mm.

[0143] In embodiments where the downstream section consists of a hollow tubular element and a mouthpiece element, the length of the downstream section is defined by the combined length of the hollow tubular element and the mouthpiece element.

[0144] Providing a relatively long downstream section, which may be defined by a relatively long combination of hollow tubular elements and mouthpiece elements, ensures that an appropriate length of the aerosol-generating article protrudes from the aerosol generator when the article is received in the aerosol generator. Such an appropriate protrusion length facilitates the ease of inserting and removing the article from the device, which also ensures that the upstream portion of the article is properly inserted into the device, reducing the risk of damage, particularly during insertion.

[0145] 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 may be about 0.75 or less. More preferably, the ratio may be about 0.70 or less. Even more preferably, the ratio may be about 0.65 or less.

[0146] The ratio between the length of the downstream section and the total length of the aerosol-generating article may be at least about 0.30. Preferably, the ratio between the length of the downstream section and the total length of the aerosol-generating article may be at least about 0.40. More preferably, the ratio between the length of the downstream section and the total length of the aerosol-generating article may be at least about 0.50. Even more preferably, the ratio between the length of the downstream section and the total length of the aerosol-generating article may be at least about 0.60.

[0147] 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 still 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 still 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 still more preferably about 0.60 to about 0.70. For example, the ratio between the length of the downstream section and the total length of the aerosol-generating article may be about 0.60 to 0.65, and more preferably, the ratio between the length of the downstream section and the total length of the aerosol-generating article may be 0.62.

[0148] 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 of the length of the downstream section to the length of the upstream section may be about 12 or less. More preferably, the ratio of the length of the downstream section to the length of the upstream section may be about 8 or less. Even more preferably, the ratio of the length of the downstream section to the length of the upstream section may be about 6 or less.

[0149] The ratio between the length of the downstream section and the length of the upstream section may be at least about 2.5. Preferably, the ratio between the length of the downstream section and the length of the upstream section may be at least about 3. More preferably, the ratio between the length of the downstream section and the length of the upstream section may be at least about 4. Even more preferably, the ratio between the length of the downstream section and the length of the upstream section may be at least about 5.

[0150] 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 still 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 still 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 still 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 still more preferably about 5.6.

[0151] The ratio between the length of the aerosol generating element (in other words, the rod of the aerosol generating substrate) and the length of the downstream section may be about 0.80 or less. Preferably, the ratio between the length of the aerosol generating element and the length of the downstream section may be about 0.70 or less. More preferably, the ratio between the length of the aerosol generating element and the length of the downstream section may be about 0.60 or less. Even more preferably, the ratio between the length of the aerosol generating element and the length of the downstream section may be about 0.50 or less.

[0152] The ratio between the length of the aerosol generating element and the length of the downstream section may be at least about 0.20. Preferably, the ratio between the length of the aerosol generating element and the length of the downstream section may be at least about 0.25. More preferably, the ratio between the length of the aerosol generating element and the length of the downstream section may be at least about 0.30. Even more preferably, the ratio between the length of the aerosol generating element and the length of the downstream section may be at least about 0.40.

[0153] In some embodiments, the ratio between the length of the aerosol generating element and 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 still more preferably about 0.40 to about 0.80. In other embodiments, the ratio between the length of the aerosol generating element and 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 still more preferably about 0.40 to about 0.70. In further embodiments, the ratio between the length of the aerosol generating element and 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 still more preferably about 0.40 to about 0.60. As an example, the ratio between the length of the aerosol generating element and the length of the downstream section may be about 0.5, more preferably about 0.45, and still more preferably about 0.43.

[0154] The downstream section of the aerosol generating article according to the present invention may comprise 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 also be provided immediately downstream of the rod of the aerosol generating substrate. In other words, the hollow tubular element may abut against 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 comprises a single hollow tubular element. In other words, the downstream section of the aerosol generating article may comprise only one hollow tubular element.

[0155] As used throughout this disclosure, the terms “hollow tubular segment” or “hollow tubular element” generally refer to 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 geometric shapes (e.g., alternative cross-sectional shapes) of tubular segments 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.

[0156] 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.

[0157] 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.

[0158] The internal volume defined by the hollow tubular element may be about 100 to 1200 cubic millimeters. Preferably, the internal volume defined by the hollow tubular element may be about 300 to 1000 cubic millimeters. The internal volume defined by the hollow tubular element may be about 700 to 900 cubic millimeters.

[0159] In the context of the present invention, the hollow tubular segment provides an unrestricted 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.

[0160] 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.

[0161] 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.

[0162] 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 a further embodiment, 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.

[0163] 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 upstream element. This is because the hollow tubular segment is substantially empty and therefore contributes only substantially little to the overall RTD of the aerosol-generating article.

[0164] Therefore, the flow channel should not contain any components that would obstruct the airflow in the longitudinal direction. The flow channel is preferably substantially empty.

[0165] In this specification, “hollow tubular segment” or “hollow tubular element” may also be referred to as “hollow tube” or “hollow tube segment.”

[0166] A hollow tubular element may comprise 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 have any of the features described herein in relation to a hollow tubular element.

[0167] As 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 a ventilation zone, or any ventilation zone, 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 zone is described further in this disclosure.

[0168] 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.

[0169] 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.

[0170] 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.

[0171] Preferably, the length of the hollow tubular element may be about 21 mm.

[0172] 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.

[0173] The ratio between the length of the aerosol generating element (in other words, the rod of the aerosol generating substrate) and the length of the hollow tubular element may be about 1.25 or less. Preferably, the ratio between the length of the aerosol generating element and the length of the hollow tubular element may be about 1 or less. More preferably, the ratio between the length of the aerosol generating element and the length of the hollow tubular element may be about 0.75 or less. Even more preferably, the ratio between the length of the aerosol generating element and the length of the hollow tubular element may be about 0.60 or less.

[0174] The ratio between the length of the aerosol generating element and the length of the hollow tubular element may be at least about 0.25. Preferably, the ratio between the length of the aerosol generating element and the length of the hollow tubular element may be at least about 0.30. More preferably, the ratio between the length of the aerosol generating element and the length of the hollow tubular element may be at least about 0.40. Even more preferably, the ratio between the length of the aerosol generating element and the length of the hollow tubular element may be at least about 0.50.

[0175] In some embodiments, the ratio between the length of the aerosol-generating element and 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 still more preferably about 0.50 to about 1.25. In other embodiments, the ratio between the length of the aerosol-generating element and 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 still more preferably about 0.50 to about 1. In further embodiments, the ratio between the length of the aerosol-generating element and 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 still more preferably about 0.50 to about 0.75. As an example, the ratio between the length of the aerosol-generating element and the length of the hollow tubular element may be about 0.6, more preferably about 0.57.

[0176] The ratio between the length of the hollow tubular element and the length of the downstream section may be about 1 or less. Preferably, the ratio between the length of the hollow tubular element and the length of the downstream section may be about 0.90 or less. More preferably, the ratio between the length of the hollow tubular element and the length of the downstream section may be about 0.85 or less. Even more preferably, the ratio between the length of the hollow tubular element and the length of the downstream section may be about 0.80 or less.

[0177] The ratio between the length of the hollow tubular element and the length of the downstream section may be at least about 0.35. Preferably, the ratio between the length of the hollow tubular element and the length of the downstream section may be at least about 0.45. More preferably, the ratio between the length of the hollow tubular element and the length of the downstream section may be at least about 0.50. Even more preferably, the ratio between the length of the hollow tubular element and the length of the downstream section may be at least about 0.60.

[0178] 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 still 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 still 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 still 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.

[0179] The ratio between the length of the hollow tubular element and the total length of the aerosol generating article may be about 0.80 or less. Preferably, the ratio between the length of the hollow tubular element and the total length of the aerosol generating article may be about 0.70 or less. More preferably, the ratio between the length of the hollow tubular element and the total length of the aerosol generating article may be about 0.60 or less. Even more preferably, the ratio between the length of the hollow tubular element and the total length of the aerosol generating article may be about 0.50 or less.

[0180] The ratio between the length of the hollow tubular element and the total length of the aerosol generating article may be at least about 0.25. Preferably, the ratio between the length of the hollow tubular element and the total length of the aerosol generating article may be at least about 0.30. More preferably, the ratio between the length of the hollow tubular element and the total length of the aerosol generating article may be at least about 0.40. Even more preferably, the ratio between the length of the hollow tubular element and the total length of the aerosol generating article may be at least about 0.45.

[0181] In some embodiments, the ratio of the length of the hollow tubular element to the total 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 still more preferably about 0.45 to about 0.80. In other embodiments, the ratio of the length of the hollow tubular element to the total 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 still more preferably about 0.45 to about 0.70. In further embodiments, the ratio of the length of the hollow tubular element to the total 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 still more preferably about 0.45 to about 0.60. For example, the ratio between the length of the hollow tubular element and the total length of the aerosol-generating article may be about 0.5, more preferably about 0.47.

[0182] 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 a sufficient amount of 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.

[0183] 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 even more preferably at least about 500 micrometers (or 0.5 mm).

[0184] 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.

[0185] 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.

[0186] The wall thickness of the hollow tubular element may preferably be about 250 micrometers (about 0.25 mm).

[0187] At the same time, keeping the thickness of the peripheral walls of the hollow tubular element relatively low ensures that the overall internal volume of the hollow tubular element (which is made available for the aerosol to begin the nucleation process as soon as the aerosol components leave the rod of the aerosol generating substrate) and the cross-sectional surface area of ​​the hollow tubular element are effectively maximized, while simultaneously ensuring that the hollow tubular element has the structural strength necessary to provide some support to the rod of the aerosol generating substrate, as well as to prevent the collapse of the aerosol generating article, and that the RTD of the hollow tubular element is minimized. A larger value of the cross-sectional surface area of ​​the cavity of the hollow tubular element is understood to be associated with a reduced rate of aerosol flow along the aerosol generating article, which is expected to be favorable for aerosol nucleation. Furthermore, by utilizing hollow tubular elements with relatively low thickness, it is thought that it is possible to substantially prevent the diffusion of the venting air before the venting air comes into contact with and mixes with the aerosol flow, which is also understood to be even more favorable for the nucleation phenomenon. In fact, by providing more controllable and localized cooling of the volatile seed flow, it is possible to enhance the cooling effect on the formation of new aerosol particles.

[0188] 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.

[0189] 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.

[0190] The 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.

[0191] 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, at least about 5 millimeters, or at least about 7 millimeters.

[0192] Providing a hollow tubular element with the inner diameter as described above is advantageous in that it may provide sufficient rigidity and strength to the hollow tubular element.

[0193] The hollow tubular element may have an inner diameter of about 10 mm or less. For example, the hollow tubular element may have an inner diameter of about 9 mm or less, about 8 mm or less, or about 7.5 mm or less.

[0194] Providing a hollow tubular element with the inner diameter as described above has the advantage of potentially reducing the draw resistance of the hollow tubular element.

[0195] 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.

[0196] 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.

[0197] The ratio between the inner diameter and outer diameter of a hollow tubular element may be at least about 0.8. For example, the ratio between the inner diameter and outer diameter of a hollow tubular element may be at least about 0.85, at least about 0.9, or at least about 0.95.

[0198] The ratio between the inner diameter and outer diameter of a hollow tubular element may be approximately 0.99 or less. For example, the ratio between the inner diameter and outer diameter of a hollow tubular element may be approximately 0.98 or less.

[0199] The ratio between the inner diameter of the hollow tubular element and the outer diameter of the hollow tubular element may be approximately 0.97.

[0200] Providing a relatively large inner diameter can be advantageous in that it reduces the withdrawal resistance of the hollow tubular element and can enhance the cooling and nucleation of aerosol particles.

[0201] The lumen or cavity of a hollow tubular element may have any cross-sectional shape. The lumen of a hollow tubular element may have a circular cross-sectional shape.

[0202] The hollow tubular element may contain a paper-based material. The hollow tubular element may have at least one layer of paper. The paper may be very rigid. The paper may be crimped paper, such as crimped heat-resistant paper or crimped sulfuric acid paper.

[0203] 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 proper engagement of articles with the inside of the device. Thus, cardboard tubes may provide adequate resistance to deformation or compression during use.

[0204] The hollow tubular element may be a paper tube. The hollow tubular element may be a tube formed from spirally wound paper. The hollow tubular element may be formed from multiple layers of paper. The paper may have a basis weight of 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.

[0205] The hollow tubular element may contain polymer materials. For example, the hollow tubular element may contain a polymer film. The polymer film may contain a cellulose film. The hollow tubular element may contain low-density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers. The hollow tubular element may contain cellulose acetate tow.

[0206] If the hollow tubular element contains cellulose acetate tow, the cellulose acetate tow may have about 2 to about 4 denier per filament and about 25 to about 40 total denier.

[0207] In some embodiments, the aerosol-generating article according to the present invention may have a ventilation zone located along the downstream section. More specifically, in those embodiments in which the downstream section comprises a hollow tubular element, the ventilation zone may be provided along the hollow tubular element.

[0208] Thus, a ventilated cavity is provided downstream of the rod of the aerosol-generating substrate. This offers several potential technical advantages.

[0209] Firstly, the inventors found that a single such ventilated, hollow tubular element provides particularly efficient cooling of the aerosol. Therefore, satisfactory cooling of the aerosol can be achieved even by a relatively short downstream section. This is particularly desirable because it enables the provision of aerosol-generating articles in which the aerosol-generating substrate (and especially those containing tobacco) is heated rather than burned, combining satisfactory aerosol delivery with efficient cooling of the aerosol to a temperature desirable for the consumer.

[0210] Secondly, the inventors surprisingly found that this rapid cooling of volatile species released upon heating of the aerosol-generating substrate promotes and enhances the nucleation of aerosol particles. This effect is particularly noticeable when the ventilation zone is positioned in a precisely defined location along the length of the hollow tubular element relative to other components of the aerosol-generating article, as will be described in more detail below. In fact, the inventors found that the favorable effect of enhanced nucleation has the ability to significantly counteract the potentially less desirable effect of dilution induced by the introduction of ventilation air.

[0211] The distance between the ventilation zone and the upstream end of the aerosol-generating article may be at least about 25 millimeters. As used herein, the term “distance between the ventilation zone and another element or part of the aerosol-generating article” refers to a distance measurement in the longitudinal direction, i.e., along or parallel to the cylindrical axis of the aerosol-generating article.

[0212] The distance between the ventilation zone and the upstream end of the aerosol-generating article is preferably at least about 26 millimeters. More preferably, the distance between the ventilation zone and the upstream end of the aerosol-generating article is at least about 27 millimeters.

[0213] The distance between the ventilation zone and the upstream end of the aerosol-generating article may be 34 millimeters or less. Preferably, the distance between the ventilation zone and the upstream end of the aerosol-generating article is 33 millimeters or less. More preferably, the distance between the ventilation zone and the upstream end of the aerosol-generating article is 31 millimeters or less.

[0214] In some embodiments, the distance between the ventilation zone and the upstream end of the aerosol-generating article is 25 to 34 millimeters, preferably 26 to 34 millimeters, and more preferably 27 to 34 millimeters.

[0215] In other embodiments, the distance between the ventilation zone and the upstream end of the aerosol-generating article is 25 to 33 millimeters, preferably 26 to 33 millimeters, and more preferably 27 to 33 millimeters.

[0216] In a further embodiment, the distance between the ventilation zone and the upstream end of the aerosol-generating article is 25 to 31 millimeters, preferably 26 to 31 millimeters, and more preferably 27 to 31 millimeters.

[0217] In some particularly preferred embodiments, the distance between the ventilation zone and the upstream end of the aerosol-generating article is 28 to 30 millimeters.

[0218] Aerosol generating articles that have a ventilation zone located along a hollow tubular element, slightly away from the upstream end of the article within the aforementioned range, have been found to offer several advantages.

[0219] Firstly, these articles have been observed to provide consumers with particularly satisfactory aerosol delivery, especially when the aerosol-generating substrate contains tobacco.

[0220] While we do not wish to be bound by theory, it is understood that the intense cooling caused by ambient air drawn into the cavity of the hollow tubular element in the ventilation zone accelerates the condensation of droplets of aerosol-forming material (e.g., glycerin) released from the aerosol-generating substrate upon heating. Subsequently, volatile nicotine and organic acids similarly released from the tobacco substrate accumulate on the newly formed droplets of aerosol-forming material and then bind to nicotine salts. As a result, the overall ratio of the aerosol particle phase to the aerosol gas phase may be higher compared to existing aerosol-generating articles.

[0221] As described above, positioning the ventilation zone slightly away from the upstream end of the aerosol-generating article is advantageous because it reduces the time the volatile nicotine particles have to dissipate before they reach the droplets of the aerosol-forming material. At the same time, this positioning of one of the ventilation zones relative to the upstream end of the aerosol-generating article ensures that there is sufficient time and room for a considerable amount of nicotine accumulation and nicotine salt formation to occur before the aerosol flow reaches the consumer's mouth.

[0222] The ventilation zone may typically comprise a plurality of perforations passing through the peripheral wall of a hollow tubular element. Preferably, the ventilation zone comprises at least one circumferential row of perforations. In some embodiments, the ventilation zone may comprise two circumferential rows of perforations. 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.

[0223] The aerosol-generating article according to the present invention may have an air permeability level of at least about 2 percent.

[0224] The term "ventilation level" is used throughout this specification to mean the volume ratio between the airflow entering the aerosol-generating article through the ventilation zone (ventilation airflow) and the sum of the aerosol airflow and the ventilation airflow. A higher ventilation level results in greater dilution of the aerosol flow delivered to the consumer. The aerosol-generating article preferably has a ventilation level of at least 5 percent, more preferably at least 10 percent, even more preferably at least 12 percent or at least 15 percent.

[0225] The aerosol-generating article according to the present invention may have a ventilation level of up to about 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.

[0226] Therefore, the aerosol generating article according to the present invention may have an air permeability level of 2 percent to 90 percent, preferably 5 percent to 90 percent, more preferably 10 percent to 90 percent, and even more preferably 15 percent to 90 percent. The aerosol generating article according to the present invention may have an air permeability level of 2 percent to 80 percent, preferably 5 percent to 80 percent, more preferably 10 percent to 80 percent, and even more preferably 15 percent to 80 percent. The aerosol generating article according to the present invention may have an air permeability level of 2 percent to 70 percent, preferably 5 percent to 70 percent, more preferably 10 percent to 70 percent, and even more preferably 15 percent to 70 percent. The aerosol generating article according to the present invention may have an air permeability level of 2 percent to 60 percent, preferably 5 percent to 60 percent, more preferably 10 percent to 60 percent, and even more preferably 15 percent to 60 percent. The aerosol generating article according to the present invention may have an air permeability level of 2 percent to 50 percent, preferably 5 percent to 50 percent, more preferably 10 percent to 50 percent, and even more preferably 15 percent to 50 percent. The aerosol-generating article preferably has an air permeability level of 30 percent or less, preferably 25 percent or less, more preferably 20 percent or less, and even more preferably 18 percent or less.

[0227] In some embodiments, the aerosol-generating article has an air permeability level of 10 to 30 percent, preferably 12 to 30 percent, and 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, and 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, and more preferably 15 to 20 percent. In a particularly preferred embodiment, the aerosol-generating article has an air permeability level of 10 to 18 percent, preferably 12 to 18 percent, and more preferably 15 to 18 percent.

[0228] 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 can have a favorable effect on the nucleation and growth of aerosol particles.

[0229] 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 1 / 2 probability). These molecules represent a kind of critical threshold molecular cluster in transient molecular aggregates, meaning that smaller molecular clusters generally decompose into the gas phase somewhat more readily, while larger clusters generally grow more readily. These critical clusters are identified as the main nucleation cores from which droplets are expected to grow due to the condensation of molecules from the vapor. The newly nucleated, untreated droplet is assumed to appear with a certain intrinsic diameter and then grow by several orders of magnitude. This can be facilitated and enhanced by the rapid cooling of the surrounding vapor, which induces condensation. In this regard, it is helpful to keep in mind that evaporation and condensation are two aspects of the same mechanism: the transfer of mass between liquid and gas. Evaporation involves net mass transfer from the droplet phase to the gas phase, while condensation is net mass transfer from the gas phase to the droplet phase. Through evaporation (or condensation), the droplet shrinks (or grows), but the number of droplets does not change.

[0230] In this scenario (which may 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.

[0231] Therefore, the rapid cooling induced by introducing outside air into a hollow tubular element through a ventilation zone can be used to favorably nucleate and grow aerosol droplets. However, at the same time, introducing outside air into a hollow tubular element has the direct disadvantage of diluting the aerosol flow delivered to the consumer.

[0232] The inventors were surprised to find that the favorable effect of enhanced nucleation, facilitated by rapid cooling induced by the introduction of aeration air into the article, significantly outweighs the less desirable effect of dilution. Thus, satisfactory values ​​of aerosol delivery are consistently achieved using the aerosol-generating article according to the present invention.

[0233] The inventors also surprisingly found that the dilution effect on aerosols, which can be evaluated by measurement, specifically the effect on the delivery of aerosol-forming substances (e.g., glycerol) contained in the aerosol-generating substrate, is advantageously minimized when the permeability level is within the aforementioned range.

[0234] 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.

[0235] This is particularly advantageous in “short” aerosol-generating articles, such as “short” aerosol-generating articles where the length of the rod of the aerosol-generating substrate is less than about 40 millimeters, preferably less than 30 millimeters, even more preferably less than 25 millimeters, and especially preferably less than 20 millimeters, or “short” aerosol-generating articles where the total length of the aerosol-generating article is less than about 70 millimeters, preferably less than about 60 millimeters, and even 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 the consumer, and thus the advantages of the enhanced nucleation described above are felt in a particularly remarkable manner.

[0236] 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 and density of any segments of the filter material forming part of the downstream section (e.g., mouthpiece elements), and optionally the length and density of the segments of the filter material provided upstream of the aerosol-generating substrate and susceptor elements. Thus, aerosol-generating articles having a predetermined RTD can be manufactured consistently and with high precision, thereby providing consumers with a satisfactory level of RTD, even in the presence of venting.

[0237] 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.

[0238] 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.

[0239] 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 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 aerosol-generating substrate rod within the aforementioned range can advantageously enhance nucleation and aerosol formation and delivery.

[0240] 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.

[0241] 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.

[0242] 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.

[0243] 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 relatively more uniform aerosol formation and delivery.

[0244] 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.

[0245] 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.

[0246] 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.

[0247] Positioning the ventilation zone a short distance within the aforementioned range from the downstream end of the aerosol-generating article has the advantage of generally ensuring that when the aerosol-generating article is partially received inside 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 is longer, it may become easier to bend the aerosol-generating article in an inadequate and undesirable manner, which may impair aerosol delivery or the intended use of the aerosol-generating article in general.

[0248] 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.

[0249] 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 a hollow tubular element, as described above. The mouthpiece element may extend between the hollow tubular element and the downstream end of the aerosol generating article. The mouthpiece element may be provided immediately downstream of the hollow tubular element. In other words, the mouthpiece element may abut the downstream end of the hollow tubular element. The mouthpiece element may define the downstream end of the downstream section of the aerosol generating article.

[0250] Parameters or characteristics described for the entire mouthpiece element may be equally applied to the mouthpiece filter segment of the mouthpiece element.

[0251] A fibrous filter material may be used to filter aerosols generated from an aerosol generating substrate. Suitable fibrous filter materials will be well known to those skilled in the art. It is particularly preferable that at least one mouthpiece filter segment includes a cellulose acetate filter segment formed from cellulose acetate tow.

[0252] In a particular preferred embodiment, the mouthpiece element consists of a single mouthpiece filter segment. In an alternative embodiment, the mouthpiece element includes two or more mouthpiece filter segments that are in contact end to end and aligned axially.

[0253] In certain embodiments of the present invention, the downstream section may comprise an oral end cavity at the downstream end 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, the outer wrapper extending downstream from (or past) the mouthpiece element.

[0254] The mouthpiece element may optionally include a flavoring agent, which may be provided in any suitable form. For example, the mouthpiece element may comprise one or more capsules, beads, or granules of the flavoring agent, or one or more threads or filaments loaded with flavoring.

[0255] The mouthpiece element, or its mouthpiece filter segment, preferably has a low particle filtration efficiency.

[0256] The mouthpiece element is preferably surrounded by a plug wrap. The mouthpiece element is preferably not permeable to air so that air does not enter the aerosol-generating article along the mouthpiece element.

[0257] The mouthpiece element is preferably connected by a chipping wrapper to one or more adjacent upstream components of the aerosol generating article.

[0258] 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.

[0259] 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.

[0260] Unless otherwise specified, the draw-out resistance (RTD) of a component or aerosol-generating article shall be measured in accordance with ISO 6565-2015. RTD refers to the pressure required to force air through the entire length of the component. The terms “pressure drop” or “draw-out resistance” of a component or article may also refer to “draw-out resistance.” These terms generally refer to the fact that the measurement in accordance with ISO 6565-2015 is successfully performed under a test of a volumetric flow rate of approximately 17.5 milliliters per 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%.

[0261] 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.

[0262] The RTD in the downstream section may be approximately 12 mmH2O or less. The RTD in the downstream section may be approximately 11 mmH2O or less. The RTD in the downstream section may be approximately 10 mmH2O or less.

[0263] 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. More preferably, the draw resistance of the downstream section may be about 3 mmH2O or more and less than about 11 mmH2O. 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.

[0264] 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.

[0265] 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.

[0266] 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.

[0267] 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. More preferably, the draw resistance of the mouthpiece element may be about 3 mmH2O or more and less than about 11 mmH2O. 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.

[0268] 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 filaments. 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 filaments.

[0269] The mouthpiece element may be formed from a polylactic acid-based material. The mouthpiece element may 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 simple and inexpensive structure for the mouthpiece element, which can be manufactured with a specific and complex cross-sectional profile that provides appropriate RTD properties and may have multiple relatively large airflow channels extending through the material of the mouthpiece element.

[0270] The mouthpiece element may be formed from a sheet of suitable material that is crumpled, pleated, assembled, woven, or folded into elements defining multiple channels extending along the long axis. Such sheets of 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.

[0271] The mouthpiece element may be formed in any other suitable manner. For example, the mouthpiece element may be formed from a bundle of tubes extending in the longitudinal direction. The tubes extending in the longitudinal direction 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 the pressure drop (or RTD) is low from the upstream end to the downstream end of the mouthpiece element.

[0272] 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.

[0273] The ratio between the length of the mouthpiece element and the length of the downstream section may be about 0.55 or less. Preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be about 0.45 or less. More preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be about 0.35 or less. Even more preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be about 0.25 or less.

[0274] The ratio between the length of the mouthpiece element and the length of the downstream section may be at least about 0.05. Preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be at least about 0.10. More preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be at least about 0.15. Even more preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be at least about 0.20.

[0275] In some embodiments, the ratio between the length of the mouthpiece element and 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 still more preferably about 0.20 to about 0.55. In other embodiments, the ratio between the length of the mouthpiece element and 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 still more preferably about 0.20 to about 0.45. In further embodiments, the ratio between the length of the mouthpiece element and 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 still more preferably about 0.20 to about 0.35. For example, the ratio between the length of the mouthpiece element and the length of the downstream section may preferably be about 0.20 to about 0.25, and more preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be about 0.25.

[0276] The ratio between the length of the mouthpiece element and the total length of the aerosol generating article may be about 0.40 or less. Preferably, the ratio between the length of the mouthpiece element and the total length of the aerosol generating article may be about 0.30 or less. More preferably, the ratio between the length of the mouthpiece element and the total length of the aerosol generating article may be about 0.25 or less. Even more preferably, the ratio between the length of the mouthpiece element and the total length of the aerosol generating article may be about 0.20 or less.

[0277] The ratio between the length of the mouthpiece element and the total length of the aerosol generating article may be at least about 0.05. Preferably, the ratio between the length of the mouthpiece element and the total length of the aerosol generating article may be at least about 0.07. More preferably, the ratio between the length of the mouthpiece element and the total length of the aerosol generating article may be at least about 0.10. Even more preferably, the ratio between the length of the mouthpiece element and the total length of the aerosol generating article may be at least about 0.15.

[0278] In some embodiments, the ratio between the length of the mouthpiece element and the total 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 still more preferably about 0.15 to about 0.40. In other embodiments, the ratio between the length of the mouthpiece element and the total 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 still more preferably about 0.15 to about 0.30. In further embodiments, the ratio between the length of the mouthpiece element and the total 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 still more preferably about 0.15 to about 0.25. For example, the ratio between the length of the mouthpiece element and the total length of the aerosol generating article may be about 0.15 to 0.20, and more preferably, the ratio between the length of the mouthpiece element and the total length of the aerosol generating article may be 0.16.

[0279] In embodiments where the downstream section comprises 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.

[0280] 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.

[0281] 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.

[0282] Preferably, the ratio of the length of the hollow tubular element to the length of the mouthpiece element may be about 3. In one such embodiment, the length of the hollow tubular element is about 21 mm, and the length of the mouthpiece element is about 7 mm.

[0283] The aerosol-generating article may have a total length of approximately 35 mm to approximately 100 mm.

[0284] 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.

[0285] 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.

[0286] 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.

[0287] 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.

[0288] 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.

[0289] 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.

[0290] 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.

[0291] In a particularly preferred embodiment, one or more of the components of the aerosol-generating article are individually enclosed by their own wrapper.

[0292] In one embodiment, the rod and mouthpiece elements 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.

[0293] At least one of the components of the aerosol-generating article is preferably wrapped with a hydrophobic wrapper.

[0294] 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 an angle conventionally measured through a 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.

[0295] In a preferred embodiment, the hydrophobic wrapper is a hydrophobic wrapper comprising 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.

[0296] As an example, the paper layer may contain PVOH (polyvinyl alcohol) or silicon. PVOH may be applied to the paper layer as a surface coating, or the paper layer may include a surface treatment containing PVOH or silicon.

[0297] In a particularly preferred embodiment, the aerosol generating article according to the present invention comprises 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 in a linear and continuous arrangement. 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.

[0298] 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.

[0299] The aerosol-generating article has a substantially cylindrical shape and an outer diameter of 7.23 millimeters.

[0300] The upstream element defining 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.

[0301] The upstream element is in the form of a hollow plug made of cellulose acetate tow wrapped in a rigid plug wrap.

[0302] The rod of the aerosol generating substrate comprises at least one of the above-described types of 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 percent by weight of glycerol.

[0303] More specifically, the hollow tubular element is in the form of a cardboard tube and has an inner diameter of approximately 6.7 millimeters. Therefore, the thickness of the peripheral wall of the hollow tubular element is approximately 0.25 millimeters.

[0304] A ventilation zone, comprising a circumferential row of openings, is provided 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 (or the upstream end of the aerosol-generating article).

[0305] The mouthpiece is in the form of a low-density cellulose acetate filter segment.

[0306] As discussed 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.

[0307] The device cavity may also be called the heating chamber of the aerosol generator. The device cavity may extend between a distal end and a mouth 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 conform to the same shape as the aerosol generating article.

[0308] The expression "received within" may refer to the fact that a component or element is fully or partially received within another component or element. For example, the expression "an aerosol-generating article is received within a device cavity" means that the aerosol-generating article is fully or partially received within the device cavity of the aerosol-generating article. When an aerosol-generating article is received within a device cavity, the aerosol-generating article may be in contact with the distal end of the device cavity. When an aerosol-generating article is received within a device cavity, the aerosol-generating article may be substantially in close proximity to the distal end of the device cavity. The distal end of the device cavity may be defined by an end wall.

[0309] 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.

[0310] 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 such that when an aerosol generating article is received into the device cavity, the downstream section or a portion thereof protrudes from the device cavity. The length of the device cavity may be such that when an 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 such that when an 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.

[0311] At least 25 percent of the length of the downstream section may be inserted into or received within the device cavity when the aerosol-generating article is received within the device. At least 30 percent of the length of the downstream section may be inserted into or received within the device cavity when the aerosol-generating article is received within the device.

[0312] At least 30 percent of the length of the hollow tubular element may be inserted into or received within the device cavity when the aerosol-generating article is received within the device. At least 40 percent of the length of the hollow tubular element may be inserted into or received within the device cavity when the aerosol-generating article is received within the device. At least 50 percent of the length of the hollow tubular element may be inserted into or received within the device cavity when the aerosol-generating article is received within the device. Various lengths of the hollow tubular element are described in more detail within this disclosure.

[0313] Optimizing the quantity or length of articles inserted into an aerosol generator may increase resistance to accidental dislodgement of articles during use. In particular, during heating of the aerosol generating substrate, the substrate may shrink, thereby reducing its outer diameter, which in turn reduces the degree to which the inserted portion of an article can frictionally engage with the device cavity. The inserted portion of an article, or the portion of an article configured to be received within the device cavity, may be the same length as the device cavity.

[0314] The length of the device cavity is preferably about 25 mm to about 29 mm. The length of the device cavity is more preferably about 26 mm to about 29 mm. The length of the device cavity is even more preferably about 27 mm or about 28 mm.

[0315] 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 inserted portion of the aerosol generating article refers to the downstream section or hollow tubular element or portion of the aerosol generating article configured to be positioned within the device cavity when the aerosol generating article is received within the device cavity. The protruding portion of the aerosol generating article refers to the article configured to be positioned outside the device cavity or to protrude from the device when the aerosol generating article is received within the device. The inventors have found that this relationship minimizes the risk of the article inadvertently coming 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.

[0316] The diameter of the device cavity may be from about 4 mm to about 10 mm. The diameter of the device cavity may be from about 5 mm to about 9 mm. The diameter of the device cavity may be from about 6 mm to about 8 mm. The diameter of the device cavity may be from about 7 mm to about 8 mm. The diameter of the device cavity may be from about 7 mm to about 7.5 mm.

[0317] 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.

[0318] The device cavity may be configured to establish a tight fit with the aerosol-generating article received within the device cavity. The tight fit may refer to a slip fit. The aerosol-generating device may comprise a peripheral wall. Such a peripheral wall may define the device cavity or the heating chamber. The peripheral wall defining the device cavity may be configured to engage in a tight fit manner with the aerosol-generating article received within the device cavity such that there is substantially no gap or empty space between the peripheral wall defining the device cavity and the aerosol-generating article when received within the device.

[0319] Such a tight fit may establish an airtight fit or configuration between the device cavity and the aerosol-generating article received therein.

[0320] In such an airtight configuration, there will be substantially no gap or empty space between the peripheral wall defining the device cavity and the aerosol-generating article through which air passes and flows.

[0321] <000,0982>The tight fit with the aerosol-generating article may be established along the entire length of the device cavity or along a portion of the length of the device cavity.

[0322] The 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 airflow into the article to deliver the generated aerosol to a user who inhales it from the mouth end of the article.

[0323] 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 peripheral boundary of the device cavity.

[0324] 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.

[0325] The heater may be any suitable type of heater. In the present invention, the heater is preferably an external heater.

[0326] Preferably, the heater may externally heat the aerosol generating article when it is received inside the aerosol generator. Such an external heater may surround the aerosol generating article when it is inserted into or received inside the aerosol generator.

[0327] In some embodiments, the heater is positioned to heat the outer surface of the aerosol generating substrate. In some embodiments, the heater is positioned for insertion into the aerosol generating substrate when the aerosol generating substrate is received within a cavity. The heater may be located within the apparatus cavity or heating chamber.

[0328] The heater may comprise at least one heating element. The at least one heating element may be any suitable type of heating element. In some embodiments, the device comprises only one heating element. In some embodiments, the device comprises multiple heating elements. The heater may comprise at least one resistive heating element. Preferably, the heater comprises multiple resistive heating elements. Preferably, the resistive heating elements are electrically connected in parallel. Advantageously, providing multiple resistive heating elements electrically connected in parallel may 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 may facilitate a reduction or minimization of the physical size of the power supply.

[0329] 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.

[0330] 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).

[0331] 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.

[0332] The electrically insulated substrate may contain any suitable material. For example, the electrically insulated substrate may contain 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 per meter Kelvin or less, preferably about 20 watts per meter Kelvin or less, and ideally about 2 watts per meter Kelvin or less.

[0333] 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 it to be directly inserted into the aerosol generating substrate. If the electrically insulated substrate is not sufficiently rigid, the heating element may be provided with further reinforcing means. An electric current may pass through one or more conductive tracks to heat the heating element and the aerosol generating substrate.

[0334] In some embodiments, the heater includes an induction heating arrangement. The induction heating arrangement may include 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. Advantageously, the heater may 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 the device cavity. In some embodiments, the inductor coil may substantially enclose the device cavity. The inductor coil may extend at least partially along the length of the device cavity.

[0335] 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 containing a material capable of converting 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 and magnetic properties of the susceptor material.

[0336] The susceptor element may be arranged such that, when the 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, causing the susceptor element to heat up. In these embodiments, the aerosol generator is preferably capable of generating a fluctuating electromagnetic field having a magnetic field strength (H magnetic field strength) of 1 to 5 kiloamperes per meter (kA / m), preferably 2 to 3 kA / m, for example about 2.5 kA / m. The electrically operated aerosol generator is preferably capable of generating a fluctuating electromagnetic field having a frequency of 1 to 30 MHz, for example 1 to 10 MHz, for example 5 to 7 MHz.

[0337] In these embodiments, the susceptor element is preferably located in contact with the aerosol-forming substrate. In some embodiments, the susceptor element is located inside the aerosol generator. In these embodiments, the susceptor element may be located inside a cavity. The aerosol generator may comprise only one susceptor element. The aerosol generator may comprise multiple susceptor elements. In some embodiments, the susceptor element is preferably arranged to heat the outer surface of the aerosol-forming substrate.

[0338] 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 composite materials of metallic materials. Some susceptor elements contain metal or carbon. Advantageously, the susceptor element may contain or consist of ferromagnetic materials such as ferrite iron, ferromagnetic alloys such as ferromagnetic steel or stainless steel, ferromagnetic particles, or 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.

[0339] The susceptor element may comprise a non-metallic core having a metal layer disposed on top of the non-metallic core. For example, the susceptor element may comprise a ceramic core or a metal track formed on the outer surface of a substrate.

[0340] In some embodiments, the aerosol generator may include at least one resistance heating element and at least one induction heating element. In some embodiments, the aerosol generator may include a combination of a resistance heating element and an induction heating element.

[0341] During use, the heater may be controlled to operate within a defined operating temperature range below the maximum operating temperature. A preferred operating temperature range is approximately 150°C to 300°C within the heating chamber (or device cavity). The heater's operating temperature range may also be approximately 150°C to 250°C.

[0342] Preferably, the heater's operating temperature range may be about 150°C to about 200°C. More preferably, the heater's operating temperature range may be about 180°C to about 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) as described in this disclosure, and using an aerosol generating device with an external heater having an operating temperature range of about 180°C to about 200°C.

[0343] In embodiments where the aerosol generating article has a ventilation zone located along a downstream section or a hollow tubular element, the ventilation zone may be arranged to be exposed when the aerosol generating article is received within the device cavity. Therefore, the length of the device cavity or heating chamber may be less than the distance from the upstream end of the aerosol generating article to the ventilation zone located along the downstream section. In other words, when the aerosol generating article is received within the aerosol generating device, the distance between the ventilation zone and the upstream end of the upstream element may be greater than the length of the heating chamber.

[0344] When an article is received in the device cavity, the ventilation zone may be located at least 0.5 mm away from the opening end (or opening end face) of the device cavity or the device itself (in the downstream direction of the article). When an article is received in the device cavity, the ventilation zone may be located at least 1 mm away from the opening end (or opening end face) of the device cavity or the device itself (in the downstream direction of the article). When an article is received in the device cavity, the ventilation zone may be located at least 2 mm away from the opening end (or opening end face) of the device cavity or the device itself (in the downstream direction of the article).

[0345] 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.

[0346] This placement of the ventilation zone ensures that it is not blocked within the device cavity itself, while also minimizing the risk of blockage by the user's lips or hands, as it is located at the upstream end from the downstream end of the article, allowing for reasonable ventilation without being blocked within the device cavity.

[0347] 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 the storage of sufficient energy for one or more user operations, such as one or more aerosol generation experiences. For example, the power supply may have a capacity that allows for continuous heating of the aerosol generating substrate for about 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 that allows for a predetermined number of puffs or discontinuous activation of the heater.

[0348] A non-exclusive list of non-limiting embodiments is provided below. One or more features of these embodiments may be combined with one or more features of other embodiments, forms, or aspects described herein.

[0349] Example 1. An aerosol generating article comprising a rod of an aerosol generating substrate and a downstream section provided downstream of the rod of the aerosol generating substrate and comprising at least one hollow tubular element. Example 2. The aerosol generating article according to Example 1, further comprising an upstream section provided upstream of the rod of the aerosol generating substrate, wherein the upstream section comprises at least one upstream element. Example 3. The aerosol generating article according to Example 2, wherein the upstream element has a length of 2 mm to 8 mm. Example 4. An aerosol generating article according to Example 2 or Example 3, wherein the upstream element is formed from a hollow tubular segment defining a longitudinal cavity that provides an unrestricted flow channel. Example 5. The aerosol generating article according to Example 4, wherein the cavity in the longitudinal direction of the hollow tubular segment has a diameter of at least 5 millimeters. Example 6. An aerosol generating article according to Example 4 or Example 5, wherein the hollow tubular segment has a wall thickness of less than 1 millimeter. 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. 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. Example 9. An aerosol generating article according to any one of Examples 1 to 8, further comprising a ventilation zone. 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. Example 11. An aerosol-generating article according to Example 9 or Example 10, wherein the ventilation zone is provided at a distance of 26 to 33 millimeters from the upstream end of the article. Example 12. An aerosol-generating article according to Example 9 or Example 10, wherein the ventilation zone is provided at a distance of 27 to 31 millimeters from the upstream end of the article. Example 13. An aerosol-generating article according to any one of Examples 9 to 12, wherein a ventilation zone is provided at a distance of 12 to 20 millimeters from the downstream end of the article. Example 14. An aerosol generating article according to any one of Examples 9 to 13, wherein a ventilation zone is provided at least 10 millimeters downstream of the downstream end of the rod of the aerosol generating substrate. Example 15. An aerosol generating article according to any of Examples 1 to 14, wherein the hollow tubular element in the downstream section has a length of 17 mm to 25 mm. Example 16. An aerosol-generating article according to any one of Examples 1 to 15, wherein the hollow tubular element in the downstream section has an internal volume of at least 300 cubic millimeters. Example 17. An aerosol generating article according to any one of Examples 1 to 16, wherein the rod of the aerosol generating substrate has a length of 8 mm to 16 mm. Example 18. An aerosol generating article according to any one of Examples 1 to 17, wherein the rod of the aerosol generating substrate has a draw-out resistance (RTD) of 4 mmH2O to 10 mmH2O. Example 19. An aerosol generating article according to any one of Examples 1 to 18, wherein the aerosol generating substrate contains shredded tobacco material. Example 20. The aerosol-generating article according to Example 19, wherein the shredded tobacco material has an average density of 150 milligrams per cubic centimeter to 500 milligrams per cubic centimeter. Example 21. An aerosol generating article according to any one of Examples 1 to 20, wherein the aerosol generating substrate contains 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. Example 22. The aerosol generating article according to Example 19, wherein the aerosol forming body contains one or more of glycerin and propylene glycol. Example 23. An aerosol generating article according to any one of Examples 1 to 22, wherein the aerosol generating substrate comprises a tobacco cut filler. Example 24. An aerosol generating article according to any of Examples 1 to 23, wherein the downstream section further comprises a mouthpiece element. 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. Example 26. An aerosol generating article according to Example 24 or Example 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. 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. Example 29. An aerosol-generating article according to any of Examples 1 to 28, wherein the article draw-out resistance (RTD) is 20 mmH2O to 22 mmH2O. Example 30. An aerosol-generating article according to any of Examples 1 to 29, wherein the outer diameter of the article is substantially uniform along its length. Example 31. An aerosol-generating article according to any one of Examples 1 to 30, wherein the ventilation level of the aerosol-generating article is 10 percent to 30 percent. Example 32. Aerosol generating article according to any of Examples 1 to 31 Example 33. An aerosol generating system comprising an aerosol generating article according to any one of Examples 1 to 32, and an aerosol generating device comprising a heating chamber for receiving the aerosol generating article and at least a heating element provided around or near the heating chamber.

[0350] The present invention will be further described below with reference to the attached drawings.

[0351] 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.

[0352] The aerosol generating article 10 has an overall length of approximately 45 mm and an outer diameter of approximately 7.2 mm.

[0353] 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 by a plug wrap (not shown). The plug wrap (not shown) for winding the aerosol generating substrate rods contains non-porous paper having a basis weight of approximately 25 grams per square meter (gsm) and a thickness of approximately 40 micrometers.

[0354] The hollow tubular element 20 is located immediately downstream of the rod 12 of the aerosol generating substrate, and is aligned with the rod 12 in the longitudinal direction. The upstream end of the hollow tubular element 20 abuts against the downstream end of the rod 12 of the aerosol generating substrate.

[0355] 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.

[0356] 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 from the upstream end of the hollow tubular element 20 to the downstream end of the hollow tubular element 20. The internal cavity 22 is substantially empty, and therefore substantially unrestricted airflow is possible along the internal cavity 22. The hollow tubular element 20 does not substantially contribute to the overall RTD of the aerosol generating article 10.

[0357] 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.

[0358] The aerosol generating article 10 includes a ventilation zone 30 provided along a hollow tubular element 20. More specifically, the ventilation zone 30 is provided about 16 mm from the downstream end 18 of the article 10. The ventilation zone 30 is provided about 12 mm downstream from the downstream end of the rod 12 of the aerosol generating substrate. The ventilation zone 30 is provided 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.

[0359] On 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.

[0360] The upstream section 40 comprises an upstream element 42 located immediately upstream of the rod 12 of the aerosol generating substrate, and the upstream element 42 is aligned with the rod 12 in the longitudinal direction. 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 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.

[0361] 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 is equipped with 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).

[0362] 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 the hollow tubular element 20. The ventilation zone 30 may also comprise a circumferential row of perforations provided on the upstream wrapper 44. The perforations of the upstream wrapper 44 overlap with the perforations provided 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.

[0363] 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 on 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. Additionally, the ventilation zone 30 may include a circumferential row of perforations provided 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 on the perforations of the ventilation zone 30 provided on the hollow tubular element 20 and the upstream wrapper 44.

[0364] Figure 3 illustrates an aerosol generating system 100 comprising 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 the aerosol generating article 10 can be received. 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.

[0365] 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.

[0366] The aerosol generator 1 further comprises a heater (not shown) and a power supply (not shown) for supplying power to the heater. A controller (not shown) is also provided to control the supply of such power to the heater. The heater is configured to controllably heat the aerosol generating article 10 during use when the aerosol generating article 1 is received inside the device 1. The heater is preferably arranged to externally heat the aerosol generating substrate 12 for optimal aerosol generation. A ventilation zone 30 is arranged to be exposed when the aerosol generating article 10 is received inside the aerosol generator 1.

[0367] 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 within the apparatus cavity, the upstream section 40, the aerosol generating substrate rod 12, and the upstream portion of the hollow tubular element 20 are received within 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 within 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 within the apparatus 1. This length PL of the article 10 protruding from the apparatus 1 is shown in Figure 3.

[0368] 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 inside the apparatus 1. For the purposes of this specification and the appended claims, unless otherwise indicated, all figures representing amounts, quantities, percentages, etc., should be understood in all cases as being modified by the term “approximately”. Also, all ranges include the disclosed maximum and minimum points and any intermediate ranges therein, which may or may not be specifically listed herein. Thus, in this context, figure A is understood as A ± 10%. In this context, figure A may be considered to include a number that is within the general standard error to the measurement of the characteristic that figure A modifies. The number A may deviate by the proportions listed above, provided that in some cases the deviation from the street used in the appended claims does not substantially affect the basic and novel characteristics of the claimed invention. Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges therewith, which may or may not be specifically listed herein.

Claims

1. Aerosol-generating article, A rod of an aerosol generating substrate, wherein the aerosol generating substrate contains 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, A mouthpiece element located downstream of the rod of an aerosol generating substrate, comprising at least one mouthpiece filter segment formed from a fibrous filter material, wherein the pull-out resistance of the mouthpiece filter segment is 4 mmH 2 0-11 mmH 2 The mouthpiece element is O, The aerosol generating substrate comprises a hollow tubular element located between the rod and the mouthpiece element, An aerosol generating article in which the combined length of the hollow tubular element and the mouthpiece element is 24 mm to 32 mm.

2. The aerosol generating article according to claim 1, wherein the internal volume defined by the hollow tubular element is at least 300 cubic millimeters.

3. The aerosol generating article according to claim 1 or claim 2, further comprising an upstream element provided upstream of the rod of the aerosol generating substrate.

4. The aforementioned upstream element is 2 mmH 2 The aerosol generating article according to claim 3, having a draw resistance of less than 0.

5. The pull-out resistance of the mouthpiece filter segment is 6 mmH 2 0-10mmH 2 An aerosol generating article according to any one of claims 1 to 4, wherein the article is O.

6. 20mmH 2 0-22mmH 2 An aerosol generating article according to any one of claims 1 to 5, having an O withdrawal resistance (RTD).

7. The aerosol generating article according to any one of claims 1 to 6, wherein the hollow tubular element consists of a continuous hollow tubular segment.

8. The aerosol generating article according to any one of claims 1 to 7, wherein the length of the hollow tubular element is at least 15 mm.

9. The aerosol generating article according to any one of claims 1 to 8, wherein the aerosol generating substrate includes shredded tobacco material.

10. The aerosol generating article according to claim 9, wherein the shredded tobacco material has a density of 150 milligrams per cubic centimeter to 500 milligrams per cubic centimeter.

11. The aerosol generating article according to any one of claims 1 to 10, wherein the length of the mouthpiece element is 3 mm to 11 mm.

12. The aerosol generating article according to any one of claims 1 to 11, wherein the wall thickness of the hollow tubular element is 2 mm or less.

13. The rod of the aerosol generation substrate has a pull-out resistance (RTD) of 4 mmHg 2 to 10 mmHg 2 The aerosol generating article according to any one of claims 1 to 12.

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

15. The aerosol generating system according to claim 14, wherein at least 30 percent of the length of the hollow tubular element is located within the heating chamber when the aerosol generating article is received within the aerosol generating device.

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