RU2839039C1 - Aerosol generating article with upstream section, hollow tubular element and ventilation - Google Patents

Abstract

FIELD: smoking accessories.

SUBSTANCE: present invention relates to an aerosol-generating article containing an aerosol-generating substrate and adapted to produce an inhaled aerosol when heated. Present invention also relates to an aerosol-generating system comprising an aerosol-generating device and said aerosol-generating article. Aerosol-generating article comprises an aerosol-generating substrate rod having length of 8 mm to 16 mm; an upstream element provided upstream of the aerosol-generating substrate rod, wherein the upstream element has an outer diameter of 6 mm to 8 mm; hollow tubular element provided downstream of the aerosol-generating substrate rod, wherein the inner volume defined by the hollow tubular element is at least 300 cubic millimeters; and a ventilation zone for providing ventilation in the aerosol generating article, wherein the ventilation zone is located at distance of 12 mm to 20 mm earlier in the flow direction relative to the said aerosol-generating end located further in the flow direction. Aerosol-generating system comprises an article, said aerosol-generating article and an aerosol-generating device comprising heating chamber to house the aerosol-generating article and at least a heating element arranged at the periphery or at the periphery of the heating chamber.

EFFECT: creation of an article with improved practicality, with satisfactory RTD and low variability of RTD from one article to another, as well as providing satisfactory aerosol delivery to the consumer.

15 cl, 3 dwg, 33 ex

Description

The present invention relates to an aerosol-generating article comprising an aerosol-generating substrate and adapted to produce an inhalable aerosol upon heating. The present invention also relates to an aerosol-generating system comprising an aerosol-generating device and said aerosol-generating article.

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

A number of prior art documents disclose aerosol generating devices for consuming aerosol generating articles. Such devices include, for example, electrically heated aerosol generating devices, in which the aerosol is generated by transferring heat from one or more electrical heating elements of the aerosol generating device to an aerosol generating substrate of the heated aerosol generating article. For example, electrically heated aerosol generating devices have been proposed that comprise an internal heating plate that is adapted to be inserted into an aerosol generating substrate. It is also known to use an aerosol generating article in combination with an external heating system. For example, document WO 2020/115151 describes the provision of one or more heating elements located along the periphery of an aerosol generating article, when the aerosol generating article is received in a cavity of the aerosol generating device. As an alternative, in WO 2015/176898, inductively heated aerosol generating articles were proposed, comprising an aerosol generating substrate and a current collector located within the aerosol generating substrate.

Aerosol-generating articles in which the tobacco-containing substrate is heated rather than combusted create a number of problems that have not been encountered with conventional smoking articles. First, the tobacco-containing substrates are typically heated to significantly lower temperatures than those reached by the combustion front in a conventional cigarette. This may impact the release of nicotine from the tobacco-containing substrate and the delivery of nicotine to the consumer. At the same time, if the heating temperature is increased in an attempt to enhance nicotine delivery, the generated aerosol typically needs to be cooled to a greater extent and more quickly before it reaches the consumer. However, technical solutions that are widely used to cool the mainstream smoke in conventional smoking articles, such as the provision of a highly efficient filtration segment at the mouth end of a cigarette, may have undesirable effects on an aerosol-generating article in which the tobacco-containing substrate is heated rather than combusted, as they may reduce nicotine delivery. Accordingly, it would be desirable to provide new aerosol generating products that can consistently provide satisfactory delivery of aerosol to the consumer.

Secondly, there is a general need for aerosol generating articles that are easy to use and have improved usability. For example, it would be desirable to provide an aerosol generating article that can be easily inserted into a heating cavity of an aerosol generating device, and at the same time, can be securely held within the heating cavity so that it does not slip out during use.

It would therefore be desirable to provide a new and improved aerosol generating article adapted to achieve at least one of the desired results described above. It would also be desirable to provide one such aerosol generating article that can be manufactured efficiently and at high speed, preferably with a satisfactory RTD and low RTD variability from one article to another.

The present invention relates to an aerosol-generating article. The aerosol-generating article may comprise a rod of aerosol-generating substrate having a length from about 8 mm to about 16 mm. The aerosol-generating article may comprise an upstream section. The upstream section may comprise an upstream element. The upstream element may be provided upstream of the rod of aerosol-generating substrate. The upstream element may have an outer diameter from about 6 mm to about 8 mm. The aerosol-generating article may comprise a hollow tubular element. The hollow tubular element may be provided downstream of the rod of aerosol-generating substrate. The internal volume defined by the hollow tubular element may be at least about 300 cubic millimeters. The aerosol generating article may comprise a ventilation zone to provide ventilation in the aerosol generating article. The ventilation zone may be located at a distance of 12 mm to 20 mm upstream of the downstream end of the aerosol generating article.

According to the present invention, an aerosol generating article is provided, comprising a rod of an aerosol generating substrate having a length from about 8 mm to about 16 mm. The aerosol generating article comprises an upstream element. The upstream element is provided upstream of the rod of the aerosol generating substrate. The upstream element has an outer diameter from about 6 mm to about 8 mm. The aerosol generating article comprises a hollow tubular element. The hollow tubular element is provided downstream of the rod of the aerosol generating substrate. The internal volume defined by the hollow tubular element is at least about 300 cubic millimeters. The aerosol generating article comprises a ventilation zone for providing ventilation in the aerosol generating article. The ventilation zone is located at a distance of 12 mm to 20 mm upstream of the aerosol-generating end of the product located further downstream.

In addition, according to the present invention, there is provided an aerosol generating system comprising an aerosol generating article as described above and an aerosol generating device, wherein the aerosol generating device comprises a heating chamber for containing the aerosol generating article and a heating element located at or along the periphery of the heating chamber.

The aerosol generating article according to the present invention provides an improved configuration that reduces the potential risk of accidental displacement or release of the aerosol generating article during use in an aerosol generating device, which may adversely affect articles having a ventilation zone. Providing the ventilation zone within a certain range of relatively large distances from the downstream end consistently minimizes the risk that the user will inadvertently block the ventilation zone during use. However, effective placement and engagement of the article within the device is necessary to ensure that the article does not fall out or slide out of the cavity of the device during use, thereby potentially negating the benefits of said specific placement of the ventilation zone.

Unintentional slippage or exit of the article from the device may open the ventilation zone further than intended. This may increase both the risk of blockage of the ventilation zone even more than when the article is properly placed in the device and the risk of misalignment of the specified length of the substrate with the heating element of the device. Thus, providing a specified relatively wide upstream element and a specified relatively long rod of the aerosol-generating substrate helps to ensure stable attachment of the article within the device, thereby minimizing such risk of accidental exit or misalignment.

During the entire heating time of the aerosol-generating substrate rod, the substrate may gradually shrink, which may adversely affect the fit of the article within the device. Providing the substrate-free component upstream of the substrate improves the adhesion or fastening of the article within the device, since the upstream element will be able to adhere to the cavity of the device, while a portion of the aerosol-generating substrate may partially and gradually come out of adhesion during use as it shrinks. In the event of any partial slippage or exit of the aerosol-generating article from the cavity of the device, a certain length of the aerosol-generating element rod can ensure proper alignment of the heater with at least a portion of the aerosol-generating element.

Additionally, in the aerosol-generating article according to the present invention, the length of the aerosol-generating substrate rod and the volume of the internal cavity of the hollow tubular element, as well as the placement of the ventilation zone relative to the end of the article located further downstream of the flow were selected to ensure rapid cooling of the compounds flowing along the cavity defined inside the hollow tubular element. It is understood that the intense cooling caused by the entry of ambient air drawn into the cavity defined inside the hollow tubular element through the ventilation zone accelerates the condensation of droplets of the substance for forming the aerosol (for example, glycerin), in which the evaporated nicotine and organic acids released during heating of the tobacco substrate accumulate and combine into nicotine salts. Taking this into account, the placement of the ventilation zone relative to the downstream end of the product was chosen to reduce the flow time of vaporized nicotine before the vaporized nicotine reaches the aerosol forming agent droplets and to minimize the risk of the user's lips blocking the ventilation zone, and to allow time and space for nicotine to accumulate and nicotine salts to form in the aerosol forming agent droplets before the aerosol stream reaches the user's mouth.

Thus, the selected diameter of the upstream element, the internal volume defined by the hollow tubular element, and the distance between the ventilation zone and the downstream end of the article in the articles according to the present invention provide a combination that optimizes the placement of the substrate within the aerosol generating device and the placement of the ventilation zone to enhance the generation and delivery of the aerosol to the consumer.

As mentioned 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. The one or more elements located downstream of the rod of the aerosol-generating substrate form a downstream section of the aerosol-generating article. Additionally, the aerosol-generating article according to the present invention may comprise an element provided upstream of the aerosol-generating substrate. The element located upstream of the rod of the aerosol-generating substrate defines an upstream section of the aerosol-generating article.

As stated above, the aerosol generating article according to the present invention comprises a rod of aerosol generating substrate. The rod of aerosol generating substrate is preferably surrounded by a wrapper such as a ficella.

The aerosol generating substrate rod preferably has a length of at least about 8 millimeters. Preferably, the aerosol generating substrate rod has a length of at least about 9 millimeters. More preferably, the aerosol generating substrate rod has a length of at least about 10 millimeters.

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

Preferably, the ratio of the length of the aerosol-generating substrate rod to the total length of the aerosol-generating article is at least about 0.15, more preferably at least about 0.2, most preferably at least about 0.22.

Preferably, the ratio of the length of the aerosol-generating substrate rod to the total length of the aerosol-generating article is less than or equal to about 0.35, more preferably less than or equal to about 0.33, more preferably less than or equal to about 0.3.

In particularly preferred embodiments of the present invention, the ratio of the length of the aerosol-generating substrate rod to the overall length of the aerosol-generating article is approximately 0.25.

The inventors of the present invention have found that by adjusting the length of the aerosol-generating substrate rod within any of the ranges described above and by controlling the density of the aerosol-generating substrate itself, it is easier to better and more consistently control the overall RTD of the aerosol-generating article. In addition, since the length of the rod is also set, it is easier to ensure the desired placement of the ventilation zone relative to the substrate and the heating device during use.

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

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

Preferably, the aerosol-generating substrate rod has an outer diameter of at least about 5 millimeters. More preferably, the aerosol-generating substrate rod has an outer diameter of at least about 6 millimeters. Even more preferably, the aerosol-generating substrate rod has an outer diameter of at least about 7 millimeters.

The aerosol generating substrate rod preferably has an outer diameter that is less than or equal to approximately 12 millimeters. More preferably, the aerosol generating substrate rod has an outer diameter that is less than or equal to approximately 10 millimeters. Even more preferably, the aerosol generating substrate rod has an outer diameter that is less than or equal to approximately 8 millimeters.

In general, it has been observed that the smaller the diameter of the aerosol-generating substrate rod, the lower the temperature required to raise the temperature of the core of the aerosol-generating substrate rod so that sufficient amounts of evaporable compounds are released from the aerosol-generating substrate to form the desired amount of aerosol. At the same time, without being limited by theory, it should be understood that a smaller diameter of the aerosol-generating substrate rod provides for a faster penetration of heat supplied to the aerosol-generating article into the entire volume of the aerosol-generating substrate. However, when the diameter of the aerosol-generating substrate rod is too small, the volume-to-surface ratio of the aerosol-generating substrate becomes less favorable since the amount of available aerosol-generating substrate decreases.

The diameter of the aerosol generating substrate rod included in the ranges described in this document is particularly advantageous in terms of the balance between energy consumption and aerosol delivery. This advantage is felt in particular when the aerosol generating article comprising the aerosol generating substrate rod having a diameter as described in this document is used in combination with an external heater located at the periphery of the aerosol generating article. It has been observed that under such operating conditions less thermal energy is required to achieve a sufficiently high temperature in the core of the aerosol generating substrate rod and in the core of the article as a whole. Thus, when operating at low temperatures, the desired target temperature in the core of the aerosol generating substrate can be achieved within a desirably reduced time frame and by means of lower energy consumption.

In some embodiments, the aerosol-generating substrate rod has an outer diameter of about 5 millimeters to about 12 millimeters, preferably about 6 millimeters to about 12 millimeters, more preferably about 7 millimeters to about 12 millimeters. In other embodiments, the aerosol-generating substrate rod has an outer diameter of about 5 millimeters to about 12 millimeters, preferably about 6 millimeters to about 10 millimeters, more preferably about 7 millimeters to about 10 millimeters. In further embodiments, the aerosol-generating substrate rod has an outer diameter of about 5 millimeters to about 8 millimeters, preferably about 6 millimeters to about 8 millimeters, more preferably about 7 millimeters to about 8 millimeters.

In particularly preferred embodiments, the aerosol-generating substrate rod has an outer diameter of less than about 7.5 millimeters. As an example, the aerosol-generating substrate rod may have an outer diameter of about 7.2 millimeters.

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

In general, the ratio between the length of the aerosol-generating substrate rod and the total length of the aerosol-generating article may be less than or equal to about 0.60. Preferably, the ratio between the length of the aerosol-generating substrate rod and the total length of the aerosol-generating article is less than or equal to about 0.50. More preferably, the ratio between the length of the aerosol-generating substrate rod and the total length of the aerosol-generating article is less than or equal to about 0.45. Even more preferably, the ratio between the length of the aerosol-generating substrate rod and the total length of the aerosol-generating article is less than or equal to about 0.40. In particularly preferred embodiments, the ratio between the length of the aerosol-generating substrate rod and the total length of the aerosol-generating article is less than or equal to about 0.35 and most preferably less than or equal to about 0.30.

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

Preferably, the rod of the aerosol-generating substrate has a substantially constant cross-section along the length of the rod. Particularly preferably, the rod of the aerosol-generating substrate has a substantially circular cross-section.

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

In the aerosol-generating article according to the present invention, the ratio between the length of the aerosol-generating substrate rod and the total length of the aerosol-generating article may be at least about 0.10. Preferably, the ratio between the length of the aerosol-generating substrate rod 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 aerosol-generating substrate rod and the total length of the aerosol-generating article may be at least about 0.20. In particularly preferred embodiments, the ratio between the length of the aerosol-generating substrate rod and the total length of the aerosol-generating article may be at least about 0.25.

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

Preferably, the density of the aerosol generating substrate is 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.

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

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

In certain preferred embodiments, the aerosol-generating substrate rod comprises shredded tobacco material, such as tobacco cut filler, with a density of from about 150 mg per cubic centimeter to about 500 mg per cubic centimeter, preferably from about 175 mg per cubic centimeter to about 450 mg per cubic centimeter, more preferably from about 200 mg per cubic centimeter to about 400 mg per cubic centimeter, more preferably from about 250 mg per cubic centimeter to about 350 mg per cubic centimeter, most preferably about 300 mg per cubic centimeter.

The RTD of the aerosol generating substrate rod is preferably less than or equal to about 10 millimeters of water column. More preferably, the RTD of the aerosol generating substrate rod is less than or equal to about 9 millimeters of water column. Even more preferably, the RTD of the aerosol generating substrate rod is less than or equal to about 8 millimeters of water column.

The RTD of the aerosol-generating substrate rod is preferably at least about 4 millimeters of water column. More preferably, the RTD of the aerosol-generating substrate rod is at least about 5 millimeters of water column. Even more preferably, the RTD of the aerosol-generating substrate rod is at least about 6 millimeters of water column.

In some embodiments, the RTD of the aerosol-generating substrate rod is from about 4 millimeters of water to about 10 millimeters of water, preferably from about 5 millimeters of water to about 10 millimeters of water, preferably from about 6 millimeters of water to about 25 millimeters of water. In other embodiments, the RTD of the aerosol-generating substrate rod is from about 4 millimeters of water to about 20 millimeters of water, preferably from about 5 millimeters of water to about 18 millimeters of water, preferably from about 6 millimeters of water to about 16 millimeters of water. In further embodiments, the RTD of the aerosol-generating substrate rod is from about 4 millimeters of water. up to about 15 millimeters of water, preferably from about 5 millimeters of water to about 14 millimeters of water, more preferably from about 6 millimeters of water to about 12 millimeters of water.

The aerosol generating substrate may be a solid aerosol generating substrate. The aerosol generating substrate preferably comprises an aerosol forming agent. The aerosol forming agent may be any suitable known compound or mixture of compounds which facilitates the formation of a dense and stable aerosol in use. The aerosol forming agent may provide the aerosol with substantial resistance to thermal degradation at temperatures typically encountered during use of the aerosol generating article. Suitable aerosol forming agents are, for example: polyhydric alcohols such as, for example, triethylene glycol, 1,3-butanediol, propylene glycol and glycerol; esters of polyhydric alcohols such as, for example, glycerol mono-, di- or triacetate; aliphatic esters of mono-, di- or polycarboxylic acids, such as, for example, dimethyl dodecanedioate and dimethyl tetradecanedioate; and combinations thereof.

Preferably, the aerosol forming agent comprises one or more of glycerin and propylene glycol. The aerosol forming agent may consist of glycerin or propylene glycol or a combination of glycerin and propylene glycol.

Preferably, the aerosol generating substrate comprises at least 5 percent by weight of the aerosol forming agent based on the dry weight of the aerosol generating substrate, more preferably from 10 percent to 22 percent by weight based on the dry weight of the cut aerosol generating substrate, more preferably the amount of the aerosol forming agent is from 12 percent to 19 percent by weight based on the dry weight of the aerosol generating substrate, most preferably, for example, the amount of the aerosol forming agent is from 13 percent to 16 percent by weight based on the dry weight of the aerosol generating substrate.

In certain preferred embodiments of the present invention, the aerosol-generating substrate comprises shredded tobacco material. For example, the shredded tobacco material may be in the form of cut filler, as described in more detail below. Alternatively, the shredded tobacco material may be in the form of a shredded sheet of homogenized tobacco material. Suitable homogenized tobacco materials for use in the present invention are described below.

In the context of this technical description, the term "cut filler" is used to describe a mixture of ground plant material, such as tobacco plant material, including in particular one or more of leaf blades, processed stems and veins, homogenized plant material.

Cut filler may also contain other trimmings, filler tobacco or casing.

Preferably, the cut filler comprises at least 25 percent of plant leaf blades, more preferably at least 50 percent of plant leaf blades, even more preferably at least 75 percent of plant leaf blades, and most preferably at least 90 percent of plant leaf blades. Preferably, the plant material is one of tobacco, mint, tea, and cloves. Most preferably, the plant material is tobacco. However, as will be described in more detail below, the present invention is equally applicable to other plant material that has the ability to release substances upon application of heat, which can subsequently form an aerosol.

Preferably, the cut filler comprises tobacco plant material comprising leaf blades of one or more of light tobacco, dark tobacco, aromatic tobacco and filler tobacco. In relation to the present invention, the term "tobacco" describes any plant belonging to the genus Nicotiana.

Light tobacco varieties are tobacco varieties with generally large, light-colored leaves. Throughout the technical description, the term light tobacco is used for tobacco varieties that have been flue-cured. Examples of light tobacco varieties are Chinese flue-cured, Brazilian flue-cured, American flue-cured such as Virginia tobacco, Indian flue-cured, Tanzanian flue-cured, or other African flue-cured. Light tobacco is characterized by a high sugar to nitrogen ratio. From an organoleptic standpoint, light tobacco is a type of tobacco that, after curing, is associated with a spicy and rich sensation. In the context of the present invention, light tobacco varieties are tobacco varieties with a reducing sugar content of about 2.5 percent to about 20 percent based on the dry weight of the leaf and a total ammonia content of less than about 0.12 percent based on the dry weight of the leaf. The reducing sugars include, for example, glucose or fructose. The total ammonia content includes, for example, ammonia and ammonia salts.

Dark tobacco varieties are tobacco varieties with typically large, dark colored leaves. Throughout the technical description, the term "dark tobacco" is used for varieties of tobacco that have been air-cured. Additionally, dark tobacco varieties may be fermented. Varieties of tobacco that are used primarily for chewing, snuff, cigars, and pipe blends are also included in this category. As a rule, these dark tobacco varieties are air-cured and possibly fermented. From an organoleptic point of view, dark tobacco is a type of tobacco that, after curing, is associated with a sensation similar to that of the smoke of dark cigars. Dark tobacco is characterized by a low sugar to nitrogen ratio. Examples of dark tobacco are Malawi Burley or other African Burley, dark cured Brazilian Galpao, and sun-cured or air-cured Indonesian Kasturi. According to the present invention, dark tobacco species are tobacco species with a reducing sugar content of less than about 5 percent based on the dry weight of the leaves and a total ammonia content of up to about 0.5 percent based on the dry weight of the leaves.

Aromatic tobacco varieties are varieties of tobacco that often have small, light-colored leaves. Throughout the technical description, the term "aromatic tobacco" is used for other varieties of tobacco that are characterized by a high content of aromatic substances, such as essential oils. From an organoleptic point of view, aromatic tobacco is a type of tobacco that, after curing, is associated with a spicy and aromatic sensation. Examples of aromatic tobacco varieties are Greek Oriental, Turkish Oriental, semi-Oriental tobacco, but also fire-cured tobacco, American Burley, such as Perique, Shag, American Burley or Maryland. Filler tobacco is not a specific type of tobacco, but includes types of tobacco that are primarily used to complement other types of tobacco used in a blend and that do not impart a specific characteristic aromatic property to the final product. Examples of filler tobacco are the stems, midribs or petioles of other types of tobacco. A specific example is the flue-cured stems from the lower petioles of the Brazilian flue-cured tobacco species.

The cut filler suitable for use in the present invention may generally resemble the cut filler used for conventional smoking articles. The cut width of the cut filler is preferably from 0.3 millimeters to 2.0 millimeters, more preferably the cut width of the cut filler is from 0.5 millimeters to 1.2 millimeters, and most preferably the cut width of the cut filler is from 0.6 millimeters to 0.9 millimeters. The cut width can play a role in the distribution of heat inside the rod of the aerosol-generating substrate. Also, the cut width can play a role in the resistance to draw of the article. In addition, the cut width can affect the overall density of the aerosol-generating substrate as a whole.

The length of the threads of the cut filler is to some extent a random value, since the length of the threads will depend on the overall size of the object from which the thread is cut. However, by maintaining appropriate conditions for the material before cutting, for example, by controlling the moisture content and the overall fineness of the material, longer threads can be cut. Preferably, the threads have a length of from about 10 millimeters to about 40 millimeters before combining the threads to form a rod of the aerosol-generating substrate. Obviously, if the threads are located in the rod of the aerosol-generating substrate in a longitudinal extension, where the longitudinal extension of the section is less than 40 millimeters, the final rod of the aerosol-generating substrate can contain threads that are on average shorter than the original thread length. Preferably, the length of the thread of the cut filler is such that from about 20 percent to 60 percent of the threads extend along the entire length of the rod of the aerosol-generating substrate. This prevents the threads from easily separating from the aerosol generating substrate core.

In preferred embodiments, the weight of the cut filler is from 80 milligrams to 400 milligrams, preferably from 150 milligrams to 250 milligrams, more preferably from 170 milligrams to 220 milligrams. This amount of cut filler usually allows to obtain enough material for the formation of an aerosol. Additionally, in light of the above-mentioned limitations on the diameter and size, this ensures a balanced density of the rod of the substrate generating an aerosol between the absorption of energy, the resistance to draw and the passages for the fluid in the rod of the substrate generating an aerosol, where the substrate generating an aerosol contains plant material.

Preferably, the cut filler is impregnated with an aerosol forming agent. Impregnation of the cut filler can be carried out by spraying or other suitable application methods. The aerosol forming agent can be added to the mixture when preparing the cut filler. For example, the aerosol forming agent can be added to the mixture in a direct conditioning housing cylinder (DCCC). Conventional equipment can be used to add the aerosol forming agent to the cut filler. The aerosol forming agent can be any suitable known compound or mixture of compounds that facilitates the formation of a dense and stable aerosol when used. The aerosol forming agent can provide substantially resistance of the aerosol to thermal degradation at temperatures typically encountered when using the aerosol-generating article. Suitable aerosol forming substances are, for example: polyhydric alcohols, such as, for example, triethylene glycol, 1,3-butanediol, propylene glycol and glycerol; esters of polyhydric alcohols, such as, for example, glycerol mono-, di- or triacetate; aliphatic esters of mono-, di- or polycarboxylic acids, such as, for example, dimethyl dodecanedioate and dimethyl tetradecanedioate; and combinations thereof.

Preferably, the aerosol forming agent comprises one or more of glycerin and propylene glycol. The aerosol forming agent may consist of glycerin or propylene glycol or a combination of glycerin and propylene glycol.

Preferably, the amount of aerosol former is at least 5 percent by weight based on the dry weight, preferably from 10 percent to 22 percent by weight based on the dry weight of the cut filler, more preferably, the amount of aerosol former is from 12 percent to 19 percent by weight based on the dry weight of the cut filler, for example, the amount of aerosol former is from 13 percent to 16 percent by weight based on the dry weight of the cut filler. When the aerosol former is added to the cut filler in the amounts described above, the cut filler can become relatively sticky. This advantageously helps to keep the cut filler in a given place inside the article, since the particles of the cut filler show a tendency to stick to the surrounding particles of the cut filler, as well as to the surrounding surfaces (for example, the inner surface of the wrapper surrounding the cut filler).

In some embodiments, the amount of aerosol forming agent has a target value of approximately 13 percent by weight based on the dry weight of the cut filler. The most effective amount of aerosol forming agent will also depend on the cut filler, regardless of whether the cut filler contains plant leaf blades or homogenized plant material. For example, among other factors, the type of cut filler will determine the extent to which the aerosol forming agent can facilitate the release of substances from the cut filler.

For these reasons, a rod of a substrate that generates an aerosol, containing a cut filler, as described above, is able to effectively generate a sufficient amount of aerosol at relatively low temperatures. Temperatures from 150 degrees Celsius to 200 degrees Celsius in a heating chamber can be sufficient for one such cut filler to generate sufficient quantities of aerosol, while aerosol generating devices that use sheets of molded tobacco leaves typically use temperatures of about 250 degrees Celsius.

An additional benefit associated with operating at lower temperatures is that the need for aerosol cooling is reduced. Since low temperatures are typically used, a simpler cooling function may be sufficient. This, in turn, allows for a simpler and less complex design of the aerosol generating product.

In other preferred embodiments, the aerosol generating substrate comprises homogenized plant material, preferably homogenized tobacco material.

In the context of this document, the term "homogenized plant material" encompasses any plant material formed by agglomerating plant particles. For example, sheets or webs of homogenized tobacco material for aerosol-generating substrates according to the present invention may be formed by agglomerating tobacco material particles obtained by grinding, milling or crushing plant material and optionally one or more of tobacco leaf lamellas and tobacco leaf veins. The homogenized plant material may be obtained by casting processes, extrusion processes, papermaking processes or any other suitable methods known in the art.

The homogenized plant material may be provided in any suitable form.

In some embodiments, the homogenized plant material may be in the form of one or more sheets. As used herein, the term "sheet" in relation to the present invention describes a layered element having a width and a length that are substantially greater than its thickness.

The homogenized plant material may be in the form of multiple beads or granules.

The homogenized plant material may be in the form of a plurality of strands, strips or pieces. In the context of this document, the term "strand" describes an elongated element of material whose length significantly exceeds its width and thickness. The term "strand" should be considered as covering strips, pieces and any other homogenized plant material having a similar shape. The strands of homogenized plant material may be formed from a sheet of homogenized plant material, for example by cutting or dividing into pieces or by other methods, for example by an extrusion method.

In some embodiments, the threads may be formed in situ within the aerosol-generating substrate as a result of dividing or splitting a sheet of homogenized plant material during the formation of the aerosol-generating substrate, such as by pleating. The threads of homogenized plant material within the aerosol-generating substrate may be separated from each other. Alternatively, each thread of homogenized plant material within the aerosol-generating substrate may be at least partially connected to an adjacent thread or threads along the length of the threads. For example, adjacent threads may be connected by one or more fibers. This may occur, for example, if the threads were formed as a result of dividing a sheet of homogenized plant material during the production of the aerosol-generating substrate, as described above.

If the homogenized plant material is in the form of one or more sheets as described above, the sheets may be produced by a casting process. Alternatively, the sheets of homogenized plant material may be produced by a papermaking process.

Each of the one or more sheets as described herein may individually have a thickness of from about 100 micrometers to 600 micrometers, preferably from 150 micrometers to 300 micrometers, and most preferably from 200 micrometers to 250 micrometers. The individual thickness refers to the thickness of an individual sheet, while the aggregate thickness refers to the total thickness of all sheets that make up the aerosol-generating substrate. For example, if the aerosol-generating substrate is formed from two individual sheets, then the aggregate thickness is the sum of the thicknesses of the two individual sheets or the measured thickness of the two sheets when the two sheets are stacked on top of each other in the aerosol-generating substrate.

Each of the one or more sheets as described herein may individually have a grammage of from about 100 grams per square meter to about 600 grams per square meter.

Each of the one or more sheets as described herein may individually have a density of from about 0.3 grams per cubic centimeter to about 1.3 grams per cubic centimeter, and preferably from about 0.7 grams per cubic centimeter to about 1.0 grams per cubic centimeter.

In embodiments of the present invention, in which the aerosol-generating substrate comprises one or more sheets of homogenized plant material, the sheets are preferably in the form of one or more assembled sheets. In the context of this document, the term "assembled" is used to describe a sheet of homogenized plant material that is rolled, bent or otherwise compressed or narrowed in a direction substantially transverse to the cylindrical axis of the plug or rod.

One or more sheets of homogenized plant material may be collected transversely relative to its longitudinal axis and surrounded by a wrapper to form a continuous rod or plug.

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

Preferably, each sheet of homogenized plant material may be corrugated so that it has a plurality of folds or corrugations substantially parallel to the cylindrical axis of the plug. This treatment advantageously facilitates the collection of the corrugated sheet of homogenized plant material to form the plug. Preferably, one or more sheets of homogenized plant material may be collected. It will be understood that the corrugated sheets of homogenized plant material may alternatively or additionally have a plurality of substantially parallel folds or corrugations located at an acute or obtuse angle to the cylindrical axis of the plug. The sheet may be corrugated to such an extent that the integrity of the sheet is disrupted at the plurality of parallel folds or corrugations, which causes separation of the material and leads to the formation of pieces, threads or strips of homogenized plant material.

Alternatively, one or more sheets of homogenized plant material can be cut into threads, as mentioned above. In such embodiments, the aerosol-generating substrate comprises a plurality of threads of homogenized plant material. The threads can be used to form a plug. Typically, the width of such threads is about 5 millimeters, or about 4 millimeters, or about 3 millimeters, or about 2 millimeters or less. The length of the threads can be greater than about 5 millimeters, from about 5 millimeters to about 15 millimeters, from about 8 millimeters to about 12 millimeters, or about 12 millimeters. Preferably, the threads have substantially the same length relative to each other.

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

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

In certain embodiments of the present invention, the homogenized plant material is a homogenized tobacco material comprising tobacco particles. Sheets of homogenized tobacco material for use in such embodiments of the present invention may have a tobacco content of at least about 40 percent by weight on a dry basis, more preferably at least about 50 percent by weight on a dry basis, more preferably at least about 70 percent by weight on a dry basis, and most preferably at least about 90 percent by weight on a dry basis.

In the context of the present invention, the term "tobacco particles" describes particles of any plant belonging to the genus Nicotiana. The term "tobacco particles" includes ground or powdered tobacco leaf lamellas, ground or powdered tobacco leaf stems, tobacco dust, tobacco fines and other tobacco by-products in the form of particles that are generated during the processing, handling and shipping of tobacco. In a preferred embodiment, the tobacco particles are substantially all derived from tobacco leaf lamellas. In contrast, separated nicotine and nicotine salts are compounds derived from tobacco, but are not considered tobacco particles for the purposes of the present invention and are not included in the percentage of particulate plant material.

The homogenized plant material may further comprise one or more aerosol forming agents. After evaporation, the aerosol forming agent may carry other vaporized compounds released from the aerosol generating substrate upon heating, such as nicotine and flavoring agents, in the aerosol. Aerosol forming agents suitable for inclusion in the homogenized plant material are known in the art and include, but are not limited to: polyhydric alcohols such as triethylene glycol, propylene glycol, 1,3-butanediol and glycerol; esters of polyhydric alcohols such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids such as dimethyl dodecanedioate and dimethyl tetradecanedioate.

The homogenized plant material may have an aerosol forming agent content of from about 5 percent to about 30 percent by weight on a dry weight basis, such as from about 10 percent to about 25 percent by weight on a dry weight basis or from about 15 percent to about 20 percent by weight on a dry weight basis. The aerosol forming agent may act as a humectant in the homogenized plant material.

As indicated above, the aerosol-generating substrate rod may be surrounded by a wrapper. The wrapper surrounding the aerosol-generating substrate rod may be a paper wrapper or a non-paper wrapper. Paper wrappers suitable for use in particular embodiments of the present invention are known in the art and include, but are not limited to, cigarette papers and filter papers. Non-paper wrappers suitable for use in particular embodiments of the present invention are known in the art and include, but are not limited to, sheets of homogenized tobacco materials.

The paper wrapper may have a square meter weight of at least 15 g/m2, preferably at least 20 g/m2. The paper wrapper may have a square meter weight of less than or equal to 35 g/m2, preferably less than or equal to 30 g/m2. The paper wrapper may have a square meter weight of 15 g/m2 to 35 g/m2, preferably 20 g/m2 to 30 g/m2. In a preferred embodiment, the paper wrapper may have a square meter weight of 25 g/m2. 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 that is less than or equal to 55 micrometers, preferably less than or equal to 50 micrometers, more preferably less than or equal to 45 micrometers. 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.

In certain preferred embodiments, the wrapper may be formed from a laminated material comprising a plurality of layers. Preferably, the wrapper is formed from a multilayer sheet comprising a layer of aluminum. The use of a multilayer sheet comprising aluminum advantageously prevents combustion of the aerosol-generating substrate, in the event that the aerosol-generating substrate is to be ignited rather than heated in the intended manner.

The paper layer of the multilayer sheet may have a square meter weight of at least 35 g/m2, preferably at least 40 g/m2. The paper layer of the multilayer sheet may have a square meter weight that is less than or equal to 55 g/m2, preferably less than or equal to 50 g/m2. The paper layer of the multilayer sheet may have a square meter weight of 35 g/m2 to 55 g/m2, preferably 40 g/m2 to 50 g/m2. In a preferred embodiment, the paper layer of the multilayer sheet may have a square meter weight of 45 g/m2.

The paper layer of the multilayer sheet may have a thickness of at least 50 micrometers, preferably at least 55 micrometers, more preferably at least 60 micrometers. The paper layer of the multilayer sheet may have a thickness of less than or equal to 80 micrometers, preferably less than or equal to 75 micrometers, more preferably less than or equal to 70 micrometers.

The paper layer of the multilayer sheet may have a thickness of 50 micrometers to 80 micrometers, preferably 55 micrometers to 75 micrometers, more preferably 60 micrometers to 70 micrometers. In a preferred embodiment, the paper layer of the multilayer sheet may have a thickness of 65 microns.

The metal layer of the multilayer sheet may have a square meter weight of at least 12 g/m2, preferably at least 15 g/m2. The metal layer of the multilayer sheet may have a square meter weight that is less than or equal to 25 g/m2, preferably less than or equal to 20 g/m2. The metal layer of the multilayer sheet may have a square meter weight of 12 g/m2 to 25 g/m2, preferably 15 g/m2 to 20 g/m2. In a preferred embodiment, the metal layer of the multilayer sheet may have a square meter weight of 17 g/m2.

The metal layer of the multilayer sheet may have a thickness of at least 2 micrometers, preferably at least 3 micrometers, more preferably at least 5 micrometers. The metal layer of the multilayer sheet may have a thickness of less than or equal to 15 micrometers, preferably less than or equal to 12 micrometers, more preferably less than or equal to 10 micrometers.

The metal layer of the multilayer sheet may have a thickness of 2 micrometers to 15 micrometers, preferably 3 micrometers to 12 micrometers, more preferably 5 micrometers to 10 micrometers. In a preferred embodiment, the metal layer of the multilayer sheet may have a thickness of 6 microns.

The wrapper surrounding the aerosol generating substrate core 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.

PVOH or silicon can be applied to the paper layer as a surface coating, for example, located on the outer surface of the paper layer of the wrapper surrounding the rod of the aerosol-generating substrate. PVOH or silicon can be located on the outer surface of the paper layer of the wrapper and form a layer thereon. PVOH or silicon can be located on the inner surface of the paper layer of the wrapper. PVOH or silicon can be located on the inner surface of the paper layer of the aerosol-generating article and form a layer thereon. PVOH or silicon can be located on the inner surface and the outer surface of the paper layer of the wrapper. PVOH or silicon can be located on the inner surface and the outer surface of the paper layer of the wrapper and form a layer thereon.

The paper wrapper containing PVOH or silicon may have a square meter weight of at least 20 g/m2, preferably at least 25 g/m2, more preferably at least 30 g/m2. The paper wrapper containing PVOH or silicon may have a square meter weight of less than or equal to 50 g/m2, preferably less than or equal to 45 g/m2, more preferably less than or equal to 40 g/m2. The paper wrapper containing PVOH or silicon may have a square meter weight of from 20 g/m2 to 50 g/m2, preferably from 25 g/m2 to 45 g/m2, more preferably from 30 g/m2 to 40 g/m2. m. In particularly preferred embodiments, the paper wrapper comprising PVOH or silicon may have a weight per square meter of approximately 35 g/m2.

The paper wrapper comprising PVOH or silicon may have a thickness of at least 25 micrometers, preferably at least 30 micrometers, more preferably at least 35 micrometers. The paper wrapper comprising PVOH or silicon may have a thickness that is less than or equal to 50 micrometers, preferably less than or equal to 45 micrometers, more preferably less than or equal to 40 micrometers. The paper wrapper comprising PVOH or silicon may have a thickness of 25 micrometers to 50 micrometers, preferably 30 micrometers to 45 micrometers, more preferably 35 micrometers to 40 micrometers. In particularly preferred embodiments, the paper wrapper comprising PVOH or silicon may have a thickness of 37 micrometers.

The wrapper surrounding the aerosol-generating substrate rod may comprise a flame retardant composition comprising one or more flame retardant compounds. The term "flame retardant compounds" is used herein to describe chemical compounds that, when added or otherwise incorporated into a carrier substrate, such as paper or plastic compounds, provide the carrier substrate with varying degrees of flame retardancy. In practice, flame retardant compounds may be activated by the presence of an ignition source and are adapted to prevent or slow down further flame propagation by a variety of different physical and chemical mechanisms.

The flame retardant composition may generally further comprise one or more non-flammability inhibiting compounds, i.e. one or more compounds such as a solvent, an auxiliary substance, a filler, which do not actively contribute to providing protection of the supporting substrate from ignition, but are used to facilitate the application of the flame retardant compound or compounds to the wrapper, or into it, or both. Some of the non-flammability inhibiting compounds of the flame retardant composition, such as solvents, are volatile and may evaporate from the wrapper upon drying after the flame retardant composition is applied to the base material for wrapping, or into it, or both. Thus, although such non-flammability inhibiting compounds are part of the flame retardant composition, they may no longer be present, or they can be found only in minor quantities in the wrapper of the aerosol-generating article.

A number of suitable flame retardant compounds are known to those skilled in the art. In particular, several flame retardant compounds and compositions suitable for treating cellulosic materials are known and have been disclosed and may find use in the manufacture of wrappers for aerosol-generating articles in accordance with the present invention.

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

In a wrapper containing a flame retardant composition suitable for use in an aerosol-generating article according to the present invention, the flame retardant composition may be provided in a treated portion of the wrapper. This means that the flame retardant composition has been applied to the corresponding portion of the base material for wrapping the wrapper, or into it, or both. Thus, in the treated portion, the wrapper has a total base dry weight that is greater than the base dry weight of the base material for wrapping. The treated portion of the wrapper can extend over at least about 10 percent of the area of the outer surface of the aerosol-generating substrate rod surrounded by the wrapper, preferably over at least about 20 percent of the area of the outer surface of the aerosol-generating substrate rod surrounded by the wrapper, more preferably over at least about 40 percent of the area of the outer surface of the aerosol-generating substrate rod, even more preferably over at least about 60 percent of the area of the outer surface of the aerosol-generating substrate rod. Most preferably, the treated portion of the wrapper extends over at least about 80 percent of the area of the outer surface of the aerosol-generating substrate rod. In particularly preferred embodiments, the treated portion of the wrapper extends over at least about 90 or even 95 percent of the area of the outer surface of the aerosol-generating substrate rod. Most preferably, the treated portion of the wrapper extends substantially over the entire area of the outer surface of the aerosol generating substrate rod.

The wrapper containing the flame retardant composition may have a square metre weight of at least 20 g/m2, preferably at least 25 g/m2, more preferably at least 30 g/m2. The wrapper containing the flame retardant composition may have a square metre weight of less than or equal to 45 g/m2, preferably less than or equal to 40 g/m2, more preferably less than or equal to 35 g/m2. The wrapper containing the flame retardant composition may have a square metre weight of from 20 g/m2 to 45 g/m2, preferably from 25 g/m2 to 40 g/m2, more preferably from 30 g/m2 to 35 g/m2. m. In some preferred embodiments, the wrapper containing the flame retardant composition may have a square meter weight of 33 g/m2.

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

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

The aerosol generating articles according to the present invention preferably comprise an upstream element positioned upstream of and adjacent to the aerosol generating substrate. The upstream element advantageously prevents direct physical contact with the upstream end of the aerosol generating substrate. For example, if the aerosol generating substrate comprises a susceptor element, the upstream element may prevent direct physical contact with the upstream end of the susceptor element. This helps to prevent displacement or deformation of the susceptor element during handling or transportation of the aerosol generating article. This, in turn, helps to maintain the shape and position of the susceptor element. In addition, the presence of the upstream element helps to prevent any loss of substrate, which may be advantageous, for example, if the substrate comprises particulate plant material.

If the aerosol generating substrate contains shredded tobacco, such as tobacco cut filler, the upstream section or element thereof may further assist in preventing the loss of loose tobacco particles from the upstream end of the article.

The upstream section or upstream element thereof may also further provide a degree of protection for the aerosol generating substrate during storage because it covers at least to some extent the upstream end of the aerosol generating substrate that may otherwise be exposed.

For aerosol-generating articles that are intended to be inserted into a cavity in an aerosol-generating device so that the aerosol-generating substrate can be heated from the outside inside the cavity, the upstream section or its upstream element can advantageously facilitate the insertion of the upstream end of the article into the cavity. The inclusion of the upstream element can further protect the end of the aerosol-generating substrate rod during the insertion of the article into the cavity, so that the risk of damage to the substrate is minimized.

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

The upstream element may be a porous element in the form of a plug. 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 from about 50 percent to about 90 percent in the longitudinal direction. The porosity of the upstream element in the longitudinal direction is determined by the ratio of the cross-sectional area of the material forming the upstream element and the internal cross-sectional area of the aerosol-generating article in the position of the upstream element.

The upstream element may be made of a porous material or may comprise a plurality of holes. This may be achieved, for example, by laser perforation. Preferably, the plurality of holes are uniformly distributed over the cross-section of the upstream element.

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

The upstream element may be formed from an air-impermeable material. In such embodiments, the aerosol-generating article may be designed such that air flows into the aerosol-generating substrate rod through suitable ventilation means provided in the wrapper.

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

The RTD of the upstream element is preferably less than or equal to about 10 millimeters of water column. More preferably, the RTD of the upstream element is less than or equal to about 5 millimeters of water column. Even more preferably, the RTD of the upstream element is less than or equal to about 2.5 millimeters of water column. Even more preferably, the RTD of the upstream element is less than or equal to about 2 millimeters of water column.

The RTD of the upstream element may be at least 0.1 mm H2O, or at least about 0.25 mm H2O, or at least about 0.5 mm H2O.

In some embodiments, the RTD of the upstream element is from about 0.1 millimeters of water to about 10 millimeters of water, preferably from about 0.25 millimeters of water to about 10 millimeters of water, preferably from about 0.5 millimeters of water to about 10 millimeters of water. In other embodiments, the RTD of the upstream element is from about 0.1 millimeters of water to about 5 millimeters of water, preferably from about 0.25 millimeters of water to about 5 millimeters of water, preferably from about 0.5 millimeters of water to about 5 millimeters of water. In further embodiments, the RTD of the upstream element is from about 0.1 millimeters of water to about 2.5 millimeters of water. RTD of the upstream element is from about 0.1 millimeters of water column to about 2 millimeters of water column, preferably from about 0.25 millimeters of water column to about 2.5 millimeters of water column, more preferably from about 0.5 millimeters of water column to about 2.5 millimeters of water column. In further embodiments, the RTD of the upstream element is from about 0.1 millimeters of water column to about 2 millimeters of water column, preferably from about 0.25 millimeters of water column to about 2 millimeters of water column, more preferably from about 0.5 millimeters of water column to about 2 millimeters of water column. In a particularly preferred embodiment, the RTD of the upstream element is about 1 millimeter of water column.

Preferably, the upstream element has an RTD of less than about 2 millimeters of water per millimeter of length, more preferably less than about 1.5 millimeters of water per millimeter of length, more preferably less than about 1 millimeter of water per millimeter of length, more preferably less than about 0.5 millimeters of water per millimeter of length, more preferably less than about 0.3 millimeters of water per millimeter of length, more preferably less than about 0.2 millimeters of water per millimeter of length.

Preferably, the combined RTD of the upstream section or its upstream element and the aerosol generating substrate rod is less than about 15 millimeters of water column, more preferably less than about 12 millimeters of water column, more preferably less than about 10 millimeters of water column.

In particularly preferred embodiments, the upstream element is formed from a hollow tubular segment defining a longitudinal cavity providing a channel for unrestricted flow. In such embodiments, the upstream element can provide protection for the aerosol-generating substrate as described above, while having a minimal impact on the overall resistance to draw (RTD) and filtration properties of the article.

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

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

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, for example, of the same material as one of the other components of the aerosol-generating article, such as a mouthpiece, a cooling element, or a support element. Suitable materials for forming the upstream element include filter materials, ceramics, a polymeric material, cellulose acetate, cardboard, zeolite, or an aerosol-generating substrate. The upstream element may comprise a cellulose acetate plug. The upstream element may comprise a hollow cellulose acetate tube or a cardboard tube.

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

Preferably, the upstream section or its upstream element has an outer diameter that is approximately equal to the outer diameter of the aerosol-generating article. Preferably, the outer diameter of the upstream section or its upstream element is from about 6 millimeters to about 8 millimeters, more preferably from about 7 millimeters to about 7.5 millimeters. Preferably, the upstream section or its upstream element has an outer diameter that is approximately 7.1 mm.

Preferably, the upstream section or the upstream element has a length of about 2 millimeters to about 8 millimeters, more preferably about 3 millimeters to about 7 millimeters, more preferably about 4 millimeters to about 6 millimeters. In a particularly preferred embodiment, the upstream section or the upstream element has a length of about 5 millimeters. The length of the upstream section or the upstream element can advantageously be varied to provide the desired overall length of the aerosol-generating article. For example, if it is desired to reduce the length of one of the other components of the aerosol-generating article, the length of the upstream section or the upstream element can be increased to maintain the same overall length of the article.

Additionally, the length of the upstream section or its upstream element can be used to control the position of the aerosol-generating article in the cavity of the aerosol-generating device for articles that are intended to be heated from the outside. This can advantageously ensure that the position of the aerosol-generating substrate within the cavity can be optimized for heating, and the position of any ventilation can be optimized.

The upstream section is preferably surrounded by a wrapper, such as a wicker. The wrapper surrounding the upstream section is preferably a rigid wicker, such as a wicker with 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.

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

As mentioned above, the aerosol-generating article according to the present invention comprises a downstream section located downstream of the aerosol-generating substrate rod. The downstream section is preferably located immediately downstream of the aerosol-generating substrate rod. The downstream section of the aerosol-generating article preferably extends between the aerosol-generating substrate rod and the downstream end of the aerosol-generating article. The downstream section may comprise one or more elements, each of which will be described in more detail within the framework of the present invention.

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

The length of the downstream section may be equal to or less than (in other words, may not be greater than) approximately 36 mm. The length of the downstream section may be equal to or less than approximately 32 mm. The length of the downstream section may be equal to or less than approximately 30 mm.

The length of the downstream section may be from about 20 mm to about 36 mm. The length of the downstream section may be from about 24 mm to about 32 mm. The length of the downstream section may be from about 26 mm to about 30 mm.

Preferably, the downstream section comprises a hollow tubular element. Preferably, the downstream section comprises a mouthpiece element. In preferred embodiments of the present invention, the downstream section comprises or consists of a hollow tubular element and a mouthpiece element, wherein the hollow tubular element is located between the rod of the aerosol-generating substrate and the mouthpiece element.

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

The total length of the hollow tubular element and the mouthpiece element may be equal to or less than approximately 36 mm. The total length of the hollow tubular element and the mouthpiece element may be equal to or less than approximately 32 mm. The total length of the hollow tubular element and the mouthpiece element may be equal to or less than approximately 30 mm.

The total length of the hollow tubular element and the mouthpiece element may be from about 20 mm to about 36 mm. The total length of the hollow tubular element and the mouthpiece element may be from about 24 mm to about 32 mm. The total length of the hollow tubular element and the mouthpiece element may be from about 26 mm to about 30 mm.

Preferably, the total length of the hollow tubular element and the mouthpiece element may be approximately 28 mm.

In embodiments where the downstream section consists of a hollow tubular element and a mouthpiece element, the length of the downstream section is determined by the sum of the lengths of the hollow tubular element and the mouthpiece element.

Providing a relatively long downstream section, which can be defined by a relatively long combination of a hollow tubular element and a mouthpiece element, ensures that a suitable length of the aerosol-generating article projects from the aerosol-generating device when the article is received therein. Such a suitable length of the projection ensures ease of insertion and removal of the article from the device, which also ensures that the upstream portions of the article are properly inserted into the device with a reduced risk of damage, especially during insertion.

The ratio between the length of the downstream section and the total length of the aerosol generating article may be less than or equal to about 0.80. Preferably, the ratio between the length of the downstream section and the total length of the aerosol generating article may be less than or equal to about 0.75. More preferably, the ratio between the length of the downstream section and the total length of the aerosol generating article may be less than or equal to about 0.70. Even more preferably, the ratio between the length of the downstream section and the total length of the aerosol generating article may be less than or equal to about 0.65.

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.

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

The ratio between the length of the downstream section and the length of the upstream section may be less than or equal to approximately 18. Preferably, the ratio between the length of the downstream section and the length of the upstream section may be less than or equal to approximately 12. More preferably, the ratio between the length of the downstream section and the length of the upstream section may be less than or equal to approximately 8. Even more preferably, the ratio between the length of the downstream section and the length of the upstream section may be less than or equal to approximately 6.

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.

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

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

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.

In some embodiments, the ratio between the length of the aerosol generating element and the length of the downstream section is from about 0.20 to about 0.80, preferably from about 0.25 to about 0.80, more preferably from about 0.30 to about 0.80, even more preferably from 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 from about 0.20 to about 0.70, preferably from about 0.25 to about 0.70, more preferably from about 0.30 to about 0.70, even more preferably from 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 from about 0.20 to about 0.60, preferably from about 0.25 to about 0.60, more preferably from about 0.30 to about 0.60, even more preferably from 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 can be about 0.5, more preferably about 0.45, even more preferably about 0.43.

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 aerosol-generating substrate rod. The hollow tubular element may be provided immediately downstream of the aerosol-generating substrate rod. In other words, the hollow tubular element may be adjacent to the downstream end of the aerosol-generating substrate rod. The hollow tubular element may define an upstream end of the downstream section of the aerosol-generating article. The hollow tubular element may be located between the aerosol-generating substrate rod 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. Preferably, the downstream section of the aerosol generating article comprises a single hollow tubular element. In other words, the downstream section of the aerosol generating article may comprise only one hollow tubular element.

In the context of this entire description of the present invention, the term "hollow tubular segment" or "hollow tubular element" is used to designate a generally elongated element that defines a lumen or passage for air flow along its longitudinal axis. In particular, the term "tubular" will be used hereinafter with reference to a tubular element that has a substantially cylindrical cross-section and defines at least one air flow channel that establishes a continuous fluid communication between an upstream end of the tubular element and a downstream end of the tubular element. However, it should be understood that alternative geometries (e.g., alternative cross-sectional shapes) of the tubular segment may be possible. The hollow tubular segment or element may be a separate, discrete element of the aerosol-generating article that has a specific length and thickness.

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

The internal volume defined by the hollow tubular element may be less than or equal to approximately 1200 cubic millimeters. Preferably, the internal volume defined by the hollow tubular element may be less than or equal to approximately 1000 cubic millimeters. The internal volume defined by the hollow tubular element may be less than or equal to approximately 900 cubic millimeters.

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

In the context of the present invention, the hollow tubular segment provides a channel for unrestricted flow. This means that the hollow tubular segment provides a negligible level of resistance to draw (RTD). The term "negligible level of RTD" is used to describe an RTD of less than 1 mm H2O per 10 millimeters of the length of the hollow tubular segment or hollow tubular element, preferably less than 0.4 mm H2O per 10 millimeters of the length of the hollow tubular segment or hollow tubular element, more preferably less than 0.1 mm H2O per 10 millimeters of the length of the hollow tubular segment or hollow tubular element.

The RTD of the hollow tubular element is preferably less than or equal to about 10 millimeters of water column. More preferably, the RTD of the hollow tubular element is less than or equal to about 5 millimeters of water column. Even more preferably, the RTD of the hollow tubular element is less than or equal to about 2.5 millimeters of water column. Even more preferably, the RTD of the hollow tubular element is less than or equal to about 2 millimeters of water column. Even more preferably, the RTD of the hollow tubular element is less than or equal to about 1 millimeter of water column.

The RTD of the hollow tubular element may be at least 0 millimeters of water, or at least about 0.25 millimeters of water, or at least about 0.5 millimeters of water, or at least about 1 millimeter of water.

In some embodiments, the RTD of the hollow tubular member is from about 0 millimeters of water to about 10 millimeters of water, preferably from about 0.25 millimeters of water to about 10 millimeters of water, preferably from about 0.5 millimeters of water to about 10 millimeters of water. In other embodiments, the RTD of the hollow tubular member is from about 0 millimeters of water to about 5 millimeters of water, preferably from about 0.25 millimeters of water to about 5 millimeters of water, preferably from about 0.5 millimeters of water to about 5 millimeters of water. In other embodiments, the RTD of the hollow tubular member is from about 1 millimeter of water to about 5 millimeters of water. In further embodiments, the RTD of the hollow tubular member is from about 0 millimeters H2O to about 2.5 millimeters H2O, preferably from about 0.25 millimeters H2O to about 2.5 millimeters H2O, more preferably from about 0.5 millimeters H2O to about 2.5 millimeters H2O. In further embodiments, the RTD of the hollow tubular member is from about 0 millimeters H2O to about 2 millimeters H2O, preferably from about 0.25 millimeters H2O to about 2 millimeters H2O, more preferably from about 0.5 millimeters H2O to about 2 millimeters H2O. In a particularly preferred embodiment, the RTD of the hollow tubular member is about 0 millimeters H2O.

In the aerosol generating articles 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 and/or upstream elements. This is because the hollow tubular segment is essentially empty and thus essentially only slightly affects the overall RTD of the aerosol generating article.

Therefore, the flow channel must be free of any components that would impede the longitudinal flow of air. Preferably, the flow channel is substantially empty.

In the present description, a "hollow tubular segment" or "hollow tubular element" may also be referred to as a "hollow tube" or a "hollow tube-shaped segment".

The hollow tubular element may comprise one or more hollow tubular segments. Preferably, the hollow tubular element consists of one (single) hollow tubular segment. Preferably, the hollow tubular element consists of a continuous hollow tubular segment. The hollow tubular segment may comprise any of the features described in the present invention with respect to the hollow tubular element.

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

The length of the hollow tubular element may be at least approximately 15 mm. The length of the hollow tubular element may be at least approximately 17 mm. The length of the hollow tubular element may be at least approximately 19 mm.

The length of the hollow tubular element may be less than or equal to approximately 30 mm. The length of the hollow tubular element may be less than or equal to approximately 25 mm. The length of the hollow tubular element may be less than or equal to approximately 23 mm.

The length of the hollow tubular element may be from about 15 mm to 30 mm. The length of the hollow tubular element may be from about 17 mm to 25 mm. The length of the hollow tubular element may be from about 19 mm to 23 mm.

Preferably, the length of the hollow tubular element may be approximately 21 mm.

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

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 less than or equal to about 1.25. Preferably, the ratio between the length of the aerosol generating element and the length of the hollow tubular element may be less than or equal to about 1. More preferably, the ratio between the length of the aerosol generating element and the length of the hollow tubular element may be less than or equal to about 0.75. Even more preferably, the ratio between the length of the aerosol generating element and the length of the hollow tubular element may be less than or equal to about 0.60.

The ratio between the length of the aerosol generating element and the length of the hollow tubular element may be at least approximately 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 approximately 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 approximately 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 approximately 0.50.

In some embodiments, the ratio between the length of the aerosol generating element and the length of the hollow tubular element is from about 0.25 to about 1.25, preferably from about 0.30 to about 1.25, more preferably from about 0.40 to about 1.25, even more preferably from 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 from about 0.25 to about 1, preferably from about 0.30 to about 1, more preferably from about 0.40 to about 1, even more preferably from 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 from about 0.25 to about 0.75, preferably from about 0.30 to about 0.75, more preferably from about 0.40 to about 0.75, even more preferably from 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 can be about 0.6, more preferably about 0.57.

The ratio between the length of the hollow tubular element and the length of the downstream section may be less than or equal to approximately 1. Preferably, the ratio between the length of the hollow tubular element and the length of the downstream section may be less than or equal to approximately 0.90. More preferably, the ratio between the length of the hollow tubular element and the length of the downstream section may be less than or equal to approximately 0.85. Even more preferably, the ratio between the length of the hollow tubular element and the length of the downstream section may be less than or equal to approximately 0.80.

The ratio between the length of the hollow tubular element and the length of the downstream section may be at least approximately 0.35. Preferably, the ratio between the length of the hollow tubular element and the length of the downstream section may be at least approximately 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 approximately 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 approximately 0.60.

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

The ratio between the length of the hollow tubular element and the total length of the aerosol-generating article may be less than or equal to approximately 0.80. Preferably, the ratio between the length of the hollow tubular element and the total length of the aerosol-generating article may be less than or equal to approximately 0.70. More preferably, the ratio between the length of the hollow tubular element and the total length of the aerosol-generating article may be less than or equal to approximately 0.60. Even more preferably, the ratio between the length of the hollow tubular element and the total length of the aerosol-generating article may be less than or equal to approximately 0.50.

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.

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

Providing a downstream section or hollow tubular element with the ratios stated above maximizes the cooling and aerosol generation benefits of a relatively long hollow tubular element while providing sufficient filtration for an aerosol generating article that is designed to be heated rather than burned. In addition, 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 determined by the RTD of the mouthpiece filter segment.

The thickness of the peripheral wall (in other words, the wall thickness) of the hollow tubular element 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).

The wall thickness of the hollow tubular element may be less than or equal to about 2 millimeters, preferably less than or equal to about 1.5 millimeters, and even more preferably less than or equal to about 1.25 millimeters. The wall thickness of the hollow tubular element may be less than or equal to about 1 millimeter. The wall thickness of the hollow tubular element may be less than or equal to about 500 micrometers.

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

The wall thickness of the hollow tubular element may preferably be approximately 250 micrometers (approximately 0.25 mm).

At the same time, maintaining a relatively small thickness of the peripheral wall of the hollow tubular element ensures that the total internal volume of the hollow tubular element, which becomes available for the aerosol to begin the nucleation process immediately after 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 at the same time ensuring that the hollow tubular element has the necessary structural strength to prevent the aerosol generating article from collapsing, as well as to provide some support for the rod of the aerosol generating substrate, and that the RTD of the hollow tubular element is minimized. It is understood that large values of the cross-sectional surface area of the cavity of the hollow tubular element are associated with a decrease in the flow velocity of the aerosol moving along the aerosol generating article, which is also expected to promote aerosol nucleation. In addition, it seems likely that by using a hollow tubular element having a relatively small thickness, it is possible to essentially prevent the diffusion of ventilation air before it comes into contact and mixes with the aerosol stream, which, as is understood, will also further promote nucleation phenomena. In practice, by providing more controlled localized cooling of the jet of evaporated compounds, it is possible to enhance the effect of cooling on the formation of new aerosol particles.

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

The hollow tubular element may have an outside diameter of 5 millimeters to 12 millimeters, such as 5 millimeters to 10 millimeters or 6 millimeters to 8 millimeters. In a preferred embodiment, the hollow tubular element has an outside diameter of 7.2 millimeters plus or minus 10 percent.

The hollow tubular element may have an internal diameter. Preferably, the hollow tubular element may have a constant internal diameter along the length of the hollow tubular element. However, the internal diameter of the hollow tubular element may vary along the length of the hollow tubular element.

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

Providing a hollow tubular member having an inner diameter as stated above can advantageously ensure sufficient rigidity and strength for the hollow tubular member.

The hollow tubular member may have an internal diameter of no more than about 10 millimeters. For example, the hollow tubular member may have an internal diameter of no more than about 9 millimeters, no more than about 8 millimeters, or no more than about 7.5 millimeters.

Providing a hollow tubular member having an inner diameter as specified above can advantageously reduce the tightening resistance of the hollow tubular member.

The hollow tubular member may have an internal diameter of from about 2 millimeters to about 10 millimeters, from about 4 millimeters to about 9 millimeters, from about 5 millimeters to about 8 millimeters, or from about 6 millimeters to about 7.5 millimeters.

The hollow tubular member may have an outside diameter of approximately 7.1 or 7.2 millimeters. The hollow tubular member may have an inside diameter of approximately 6.7 millimeters.

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

The ratio between the inner diameter of the hollow tubular element and the outer diameter of the hollow tubular element may be no more than approximately 0.99. For example, the ratio between the inner diameter of the hollow tubular element and the outer diameter of the hollow tubular element may be no more than approximately 0.98.

The ratio between the inner diameter of the hollow tubular member and the outer diameter of the hollow tubular member may be approximately 0.97.

Providing a relatively large inner diameter can advantageously reduce the tightening resistance of the hollow tubular member and improve the cooling and nucleation of aerosol particles.

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

The hollow tubular element may comprise a paper-based material. The hollow tubular element may comprise at least one layer of paper. The paper may be a very rigid paper. The paper may be a corrugated paper, such as corrugated heat-resistant paper or corrugated parchment paper.

Preferably, the hollow tubular element may comprise cardboard. The hollow tubular element may be a cardboard tube. The hollow tubular element may be formed from cardboard. Advantageously, cardboard is an economical material that provides a balance between the ability to deform to ensure easy insertion of the article into the aerosol generating device and sufficient rigidity to ensure suitable engagement of the article with the interior of the device. Therefore, the cardboard tube can provide suitable resistance to deformation or compression during use.

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 a plurality of layers of paper. The paper may have a basis weight of at least about 50 grams per square meter, at least about 60 grams per square meter, at least about 70 grams per square meter, or at least about 90 grams per square meter.

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

When the hollow tubular member comprises cellulose acetate tow, the cellulose acetate tow may have a denier per filament of from about 2 to about 4 and a total denier of from about 25 to about 40.

In some embodiments, the aerosol-generating article according to the present invention may comprise a ventilation zone at a location along the downstream section. In more detail, in those embodiments where the downstream section comprises a hollow tubular element, the ventilation zone may be provided at a location along the hollow tubular element.

The ventilated cavity is thus provided downstream of the aerosol-generating substrate rod. This provides several potential technical advantages.

First, the inventors of the present invention have found that a single such ventilated hollow tubular segment provides particularly effective cooling of the aerosol. Thus, satisfactory cooling of the aerosol can be achieved even by a relatively short downstream section. This is particularly desirable since it provides an aerosol-generating article wherein the aerosol-generating substrate (and in particular the tobacco-containing substrate) is heated rather than burned, which combines satisfactory delivery of the aerosol with effective cooling of the aerosol to temperatures that are desirable for the consumer.

Secondly, the inventors of the present invention have unexpectedly found that such rapid cooling of the volatile compounds released by heating the aerosol-generating substrate promotes improved nucleation of the aerosol particles. This effect is felt in particular when, as will be described in more detail below, the ventilation zone is located at a precisely defined location along the length of the hollow tubular element relative to other components of the aerosol-generating article. In fact, the inventors of the present invention have found that the beneficial effect of enhanced nucleation can significantly counteract the potentially less desirable dilution effects caused by the introduction of ventilation air.

The distance between the ventilation zone and the upstream end of the aerosol-generating article may be at least 25 millimetres. In the context of this document, the term "distance between the ventilation zone and another element or part of the aerosol-generating article" refers to the distance measured in the longitudinal direction, i.e. in the direction running along or parallel to the cylindrical axis of the aerosol-generating article.

Preferably, the distance between the ventilation zone and the upstream end of the aerosol-generating article is at least 26 millimeters. More preferably, the distance between the ventilation zone and the upstream end of the aerosol-generating article is at least 27 millimeters.

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

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

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

In further embodiments, the distance between the ventilation zone and the upstream end of the aerosol generating article is from 25 millimeters to 31 millimeters, preferably from 26 millimeters to 31 millimeters, more preferably from 27 millimeters to 31 millimeters.

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

It has been found that aerosol generating articles comprising a ventilation zone at a location along the hollow tubular member at a distance from the upstream end of the aerosol generating article within the ranges described above have numerous advantages.

Firstly, it has been observed that such products provide particularly satisfactory aerosol delivery to the consumer, particularly if the aerosol generating substrate contains tobacco.

Without being limited by theory, it should be understood that the intense cooling caused by the ambient air drawn into the cavity of the hollow tubular element in the ventilation zone accelerates the condensation of droplets of the aerosol-forming substance (e.g., glycerin) that was released from the aerosol-generating substrate during heating. In turn, the vaporized nicotine and organic acids similarly released from the tobacco substrate accumulate on the newly formed droplets of the aerosol-forming substance and subsequently combine into nicotine salts. Accordingly, the overall ratio of the particulate aerosol phase to the gas phase of the aerosol can be improved compared to existing aerosol-generating products.

The arrangement of the ventilation zone at a distance from the upstream end of the aerosol-generating article, as described above, advantageously reduces the flow time of the vaporized nicotine before the vaporized nicotine particles reach the droplets of the substance to form the aerosol. At the same time, such arrangement of the ventilation zone alone relative to the upstream end of the aerosol-generating article ensures that there is sufficient time and space for the accumulation of nicotine and the formation of nicotine salts in a significant proportion before the aerosol flow reaches the consumer's mouth.

The ventilation zone may typically comprise a plurality of perforations in the peripheral wall of the hollow tubular element. Preferably, the ventilation zone comprises at least one annular row of perforations. In some embodiments, the ventilation zone may comprise two annular rows of perforations. For example, the perforations may be formed on a production line during the manufacturing process of an aerosol-generating article. Preferably, each annular row of perforations comprises from 8 to 30 perforations.

The aerosol generating article of the present invention may have a ventilation level of at least about 2 percent.

The term "ventilation level" is used throughout this description to denote the volumetric ratio between the air flow admitted into the aerosol-generating article through the ventilation zone (ventilation air flow) and the sum of the aerosol-containing air flow and the ventilation air flow. The higher the ventilation level, the greater the 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.

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 that is less than or equal to 80 percent, more preferably less than or equal to 70 percent, even more preferably less than or equal to 60 percent, most preferably less than or equal to 50 percent.

Thus, the aerosol-generating article according to the present invention may have a ventilation level of from 2 percent to 90 percent, preferably from 5 percent to 90 percent, more preferably from 10 percent to 90 percent, even more preferably from 15 percent to 90 percent. The aerosol-generating article according to the present invention may have a ventilation level of from 2 percent to 80 percent, preferably from 5 percent to 80 percent, more preferably from 10 percent to 80 percent, even more preferably from 15 percent to 80 percent. The aerosol-generating article according to the present invention may have a ventilation level of from 2 percent to 70 percent, preferably from 5 percent to 70 percent, more preferably from 10 percent to 70 percent, even more preferably from 15 percent to 70 percent. The aerosol-generating article according to the present invention may have a ventilation level of 2 percent to 60 percent, preferably 5 percent to 60 percent, more preferably 10 percent to 60 percent, even more preferably 15 percent to 60 percent. The aerosol-generating article according to the present invention may have a ventilation level of 2 percent to 50 percent, preferably 5 percent to 50 percent, more preferably 10 percent to 50 percent, even more preferably 15 percent to 50 percent. The aerosol-generating article preferably has a ventilation level that is less than or equal to 30 percent, preferably less than or equal to 25 percent, more preferably less than or equal to 20 percent, even more preferably less than or equal to 18 percent.

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

Without being limited by theory, the present inventors have found that a temperature difference caused by admitting cooler outside air into a hollow tubular member through a ventilation zone can have a beneficial effect on the nucleation and growth of aerosol particles.

The formation of an aerosol from a gaseous mixture containing various chemical compounds depends on the subtle interactions of nucleation, evaporation and condensation, and droplet coalescence, while taking into account changes in concentration, temperature and vapor velocity fields. The so-called classical nucleation theory is based on the assumption that the fraction of molecules in the gas phase is large enough for them to remain coherent for a long time with a sufficient probability (e.g., with a probability of five tenths). These molecules represent some kind of critical threshold molecular clusters among the transient molecular aggregates, which means that, on average, smaller molecular clusters are more likely to disintegrate sufficiently quickly into the gas phase, whereas larger clusters are, on average, more likely to grow. Such a critical cluster is identified with the key nucleation nucleus from which droplet growth is expected due to condensation of molecules from the vapor. Primary droplets that have just formed are assumed to appear with a certain initial diameter and can then grow by several orders of magnitude. This is simplified and can be accelerated by rapid cooling of the surrounding vapor, which causes condensation. In this regard, it should be remembered that evaporation and condensation are two sides of the same mechanism, namely mass transfer between a gas and a liquid. Whereas evaporation refers to a net mass transfer from the liquid droplets to the gas phase, condensation is a net mass transfer from the gas phase to the droplet phase. Evaporation (or condensation) will cause a decrease in the volume (or growth) of the droplets, but will not change the number of droplets.

In this scenario, which may be further complicated by droplet coalescence phenomena, temperature and cooling rate may play an important role in determining the response of the system. In general, different cooling rates may result in significantly different time behavior with respect to liquid phase (droplet) formation, since the nucleation process is typically nonlinear. Without being limited by theory, it is suggested that cooling may cause a rapid decrease in the droplet number concentration, followed by a strong short-term increase in droplet growth (nucleation burst). This nucleation burst may be more significant at lower temperatures. It may also be that higher cooling rates may favor an earlier onset of nucleation. Conversely, a decrease in the cooling rate may have a beneficial effect on the final size that the aerosol droplets eventually reach.

Therefore, the rapid cooling caused by the admission of external air into the hollow tubular element through the ventilation zone can be advantageously used to promote the nucleation and growth of aerosol droplets. However, at the same time, the immediate disadvantage of admitting external air into the hollow tubular element is the dilution of the aerosol stream delivered to the consumer.

The inventors of the present invention have surprisingly discovered how the beneficial effect of improved nucleation provided by rapid cooling caused by the introduction of ventilation air into the article can significantly counteract the less desirable dilution effects. Thus, satisfactory aerosol delivery values are consistently achieved by the aerosol-generating articles according to the present invention.

The inventors of the present invention also unexpectedly found that the effect of dilution on the aerosol, which can be assessed by measuring, in particular the effect on the delivery of an aerosol forming substance (e.g., glycerol) contained in an aerosol generating substrate, is advantageously minimized when the ventilation level is within the ranges described above.

In particular, it was found that ventilation levels from 10 percent to 20 percent and even more preferably from 12 to 18 percent lead to particularly satisfactory glycerol delivery values.

This is particularly advantageous for "short" aerosol-generating articles, such as articles in which the length of the aerosol-generating substrate rod 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 in which the overall length of the aerosol-generating article is less than about 70 millimeters, preferably less than about 60 millimeters, even more preferably less than 50 millimeters. It will be appreciated that in such aerosol-generating articles there is typically little time and space for the aerosol to form and for the particulate phase of the aerosol to be available for delivery to the consumer, and therefore the benefits of the improved nucleation described above are felt particularly significantly.

In addition, since the ventilated hollow tubular element does not substantially affect the overall RTD of the aerosol-generating article in aerosol-generating articles, in accordance with the present invention, the overall RTD of the article can be advantageously precisely controlled by adjusting the length and density of the rod of the aerosol-generating substrate, or the length and optionally the length and density of any segment of the filter material that forms part of a downstream section, such as, for example, a mouthpiece element, or the length and density of a segment of the filter material provided upstream of the aerosol-generating substrate and the susceptor element. In this way, aerosol-generating articles that have a given RTD can be manufactured consistently and with great accuracy, so that satisfactory RTD levels can be provided to the consumer even in the presence of ventilation.

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

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

In some embodiments, the distance between the ventilation zone and the downstream end of the aerosol-generating substrate rod is from 4 millimeters to 17 millimeters, preferably from 7 millimeters to 17 millimeters, even more preferably from 10 millimeters to 17 millimeters. In other embodiments, the distance between the ventilation zone and the downstream end of the aerosol-generating substrate rod is from 8 millimeters to 16 millimeters, preferably from 9 millimeters to 16 millimeters, more preferably from 10 millimeters to 16 millimeters. In further embodiments, the distance between the ventilation zone and the downstream end of the aerosol-generating substrate rod is from 8 millimeters to 15 millimeters, preferably from 9 millimeters to 15 millimeters, more preferably from 10 millimeters to 15 millimeters. As an example, the distance between the ventilation zone and the downstream end of the aerosol-generating substrate rod may be from 10 millimeters to 14 millimeters, preferably from 10 millimeters to 13 millimeters, even more preferably from 10 millimeters to 12 millimeters. The advantage of arranging the ventilation zone at a distance from the downstream end of the aerosol-generating substrate rod within the ranges described above is that it generally ensures that during use, the ventilation zone is immediately outside the heating device when the aerosol-generating article is inserted into the heating device. It has further been found that arranging the ventilation zone at a distance from the downstream end of the aerosol-generating substrate rod within the ranges described above can advantageously improve nucleation and aerosol formation and delivery.

The distance between the ventilation zone and the end of the hollow tubular element located further downstream may be at least 3 millimetres. Preferably, the distance between the ventilation zone and the end of the hollow tubular element located further downstream is at least 5 millimetres. More preferably, the distance between the ventilation zone and the end of the hollow tubular element located further downstream is at least 7 millimetres.

The distance between the ventilation zone and the end of the hollow tubular element located further downstream is preferably less than or equal to 14 millimeters. More preferably, the distance between the ventilation zone and the end of the hollow tubular element located further downstream is less than or equal to 12 millimeters. Even more preferably, the distance between the ventilation zone and the end of the hollow tubular element located further downstream is less than or equal to 10 millimeters.

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

An advantage of arranging the ventilation zone at a distance from the downstream end of the hollow tubular element within the ranges described above is that it generally ensures that during use, the ventilation zone is located just outside the heating device when the aerosol-generating article is inserted into the heating device. In addition, it has been found that arranging the ventilation zone at a distance from the downstream end of the hollow tubular element within the ranges described above can advantageously result in the formation and delivery of a comparatively more uniform aerosol.

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.

The distance between the ventilation zone and the downstream end of the aerosol-generating article is preferably less than or equal to 21 millimeters. More preferably, the distance between the ventilation zone and the downstream end of the aerosol-generating article is less than or equal to 19 millimeters. Even more preferably, the distance between the ventilation zone and the downstream end of the aerosol-generating article is less than or equal to 17 millimeters.

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

The advantage of arranging the ventilation zone at a distance from the downstream end of the aerosol-generating article within the ranges described above is that it generally ensures that during use, when the aerosol-generating article is partially contained within the heating device, the portion of the aerosol-generating article extending beyond the heating device is of sufficient length for the consumer to comfortably hold the article between his or her lips. At the same time, the data indicate that if the length of the portion of the aerosol-generating article extending beyond the heating device were greater, the aerosol-generating article could easily be unintentionally and undesirably bent, and this could impair the delivery of the aerosol or the overall intended use of the aerosol-generating article.

As discussed in the present invention, the downstream section may comprise 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.

The mouthpiece element may be provided downstream of the aerosol-generating substrate rod. The mouthpiece element may extend the entire distance to the mouthpiece end of the aerosol-generating article. The mouthpiece element may comprise at least one filter segment of the mouthpiece formed from a fibrous filter material. The mouthpiece element may be located downstream of the hollow tubular element, which is 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 adjoin 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.

The parameters or characteristics described in relation to the mouthpiece element may generally be equally applied to the mouthpiece filter segment of the mouthpiece element.

The fibrous filter material can be designed to filter an aerosol generated from an aerosol-generating substrate. Suitable fibrous filter materials will be known to a person skilled in the art. Particularly preferably, at least one filter segment of the mouthpiece comprises an acetyl cellulose filter segment formed from an acetyl cellulose tow.

In certain preferred embodiments, the mouthpiece element consists of a single filter mouthpiece segment. In alternative embodiments, the mouthpiece element comprises two or more filter mouthpiece segments coaxially aligned end-to-end with one another.

In certain embodiments of the present invention, the downstream section may comprise a mouth end cavity at a downstream end located downstream of the mouth tip element, as described above. The mouth end cavity may be defined by an additional hollow tubular element provided at the downstream end of the mouth tip. Alternatively, the mouth end cavity may be defined by an outer wrapper of the aerosol-generating article, wherein the outer wrapper extends in a direction downstream of (or past) the mouth tip element.

The mouthpiece element may optionally contain a flavoring agent, which may be provided in any suitable form. For example, the mouthpiece element may contain one or more capsules, beads or granules of a flavoring agent, or one or more threads or fibers filled with a flavoring agent.

Preferably, the mouthpiece element or its mouthpiece filter segment has a low particle filtration efficiency.

Preferably, the mouthpiece element is surrounded by a wick. Preferably, the mouthpiece element is not ventilated, so that air does not enter the aerosol-generating article along the mouthpiece element.

The mouthpiece element is preferably connected to one or more adjacent upstream components of the aerosol generating article by means of a rim wrap.

The mouthpiece element preferably has an outer diameter that is approximately equal to the outer diameter of the aerosol-generating article. The diameter of the mouthpiece element (or filter segment of the mouthpiece) can be substantially the same as the outer diameter of the hollow tubular element. As mentioned in the present invention, the outer diameter of the hollow tubular element can be approximately 7.2 mm, plus or minus 10 percent.

The diameter of the mouthpiece element may be from about 5 mm to about 10 mm. The diameter of the mouthpiece element may be from about 6 mm to about 8 mm. The diameter of the mouthpiece element may be from about 7 mm to about 8 mm. The diameter of the mouthpiece element may be about 7.2 mm, plus or minus 10 percent. The diameter of the mouthpiece element may be about 7.25 mm, plus or minus 10 percent.

Unless otherwise specified, the resistance to draw (RTD) of an aerosol-generating component or article is measured in accordance with ISO 6565-2015. RTD refers to the pressure required to force air through the entire length of the component. The terms "pressure drop" or "resistance to draw" of a component or article may also refer to "resistance to draw". Such terms generally refer to measurements in accordance with ISO 6565-2015, which are typically performed under test conditions at a volumetric flow rate of approximately 17.5 millilitres per second at the outlet 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%.

The resistance to draw (RTD) of the downstream section may be at least about 0 mm H2O. The RTD of the downstream section may be at least about 3 mm H2O. The RTD of the downstream section may be at least about 6 mm H2O.

The RTD of the downstream section may be no more than approximately 12 mm H2O. The RTD of the downstream section may be no more than approximately 11 mm H2O. The RTD of the downstream section may be no more than approximately 10 mm H2O.

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

The resistance to draw (RTD) characteristics of a downstream section may be completely or largely related to the RTD characteristics of the mouthpiece element of the downstream section. In other words, the RTD of the mouthpiece element of the downstream section may completely determine the RTD of the downstream section.

The resistance to draw (RTD) of the mouthpiece element may be at least about 0 mm H2O. The RTD of the mouthpiece element may be at least about 3 mm H2O. The RTD of the mouthpiece element may be at least about 6 mm H2O.

The RTD of the mouthpiece element may be no more than about 12 mm H2O. The RTD of the mouthpiece element may be no more than about 11 mm H2O. The RTD of the mouthpiece element may be no more than about 10 mm H2O.

The draw resistance of the mouthpiece element may be greater than or equal to about 0 mm H2O and less than about 12 mm H2O. Preferably, the draw resistance of the mouthpiece element may be greater than or equal to about 3 mm H2O and less than about 12 mm H2O. The draw resistance of the mouthpiece element may be greater than or equal to about 0 mm H2O and less than about 11 mm H2O. Even more preferably, the draw resistance of the mouthpiece element may be greater than or equal to about 3 mm H2O and less than about 11 mm H2O. Even more preferably, the draw resistance of the mouthpiece element may be greater than or equal to about 6 mm H2O and less than about 10 mm H2O. Preferably, the draw resistance of the mouthpiece element may be about 8 mm H2O.

As mentioned above, the mouthpiece element or the filter segment of the mouthpiece 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 a denier per fiber of from about 10 to about 15. For example, the mouthpiece element is formed from a relatively low-density cellulose acetate tow, such as a cellulose acetate tow containing fibers of about 12 denier per fiber.

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. Bioplastic-based materials are advantageous because they are capable of providing mouthpiece element structures that are simple and inexpensive to manufacture with a specific and complex cross-sectional profile that may contain several relatively large air flow channels passing through the mouthpiece element material, which provides suitable RTD characteristics.

The mouthpiece element may be formed from a sheet of suitable material that has been corrugated, pleated, gathered, woven or bent into an element that defines a plurality of longitudinally extending channels. Such a sheet of suitable material may be formed from paper, cardboard, a polymer such as polylactic acid, or any other cellulose-based material, paper-based material or bioplastic-based material. The cross-sectional profile of such a mouthpiece element may show the channels as randomly oriented.

The mouthpiece element may be formed by any other suitable method. For example, the mouthpiece element may be formed from a bundle of longitudinally extending tubes. The longitudinally extending tubes may be formed from polylactic acid. The mouthpiece element may be formed by extrusion, casting, lamination, injection or milling of a suitable material. Thus, it is preferable that there is a small pressure drop (or RTD) from the upstream end of the mouthpiece element to the downstream end of the mouthpiece element.

The length of the mouthpiece element may be at least approximately 3 mm. The length of the mouthpiece element may be at least approximately 5 mm. The length of the mouthpiece element may be equal to or less than approximately 11 mm. The length of the mouthpiece element may be equal to or less than approximately 9 mm. The length of the mouthpiece element may be from approximately 3 mm to approximately 11 mm. The length of the mouthpiece element may be from approximately 5 millimeters to approximately 9 millimeters. Preferably, the length of the mouthpiece element may be approximately 7 mm.

The ratio between the length of the mouthpiece element and the length of the downstream section may be less than or equal to approximately 0.55. Preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be less than or equal to approximately 0.45. More preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be less than or equal to approximately 0.35. Even more preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be less than or equal to approximately 0.25.

The ratio between the length of the mouthpiece element and the length of the downstream section may be at least approximately 0.05. Preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be at least approximately 0.10. More preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be at least approximately 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 approximately 0.20.

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

The ratio between the length of the mouthpiece element and the total length of the aerosol-generating article may be less than or equal to approximately 0.40. Preferably, the ratio between the length of the mouthpiece element and the total length of the aerosol-generating article may be less than or equal to approximately 0.30. More preferably, the ratio between the length of the mouthpiece element and the total length of the aerosol-generating article may be less than or equal to approximately 0.25. Even more preferably, the ratio between the length of the mouthpiece element and the total length of the aerosol-generating article may be less than or equal to approximately 0.20.

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.

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

In embodiments where the downstream section comprises a hollow tubular element and a mouthpiece element, the ratio between the length of the hollow tubular element and the length of the mouthpiece element may be at least approximately 1.25. In other words, the length of the hollow tubular element may be equivalent to approximately 125% of the length of the mouthpiece. The ratio between the length of the hollow tubular element and the length of the mouthpiece element may be at least approximately 1.5. The ratio between the length of the hollow tubular element and the length of the mouthpiece element may be at least approximately 2.

The ratio between the length of the hollow tubular element and the length of the mouthpiece element may be equal to or less than approximately 8.5. The ratio between the length of the hollow tubular element and the length of the mouthpiece element may be equal to or less than approximately 6. The ratio between the length of the hollow tubular element and the length of the mouthpiece element may be equal to or less than approximately 4.

The ratio between the length of the hollow tubular element and the length of the mouthpiece element may be from about 1.25 to about 8.5. The ratio between the length of the hollow tubular element and the length of the mouthpiece element may be from about 1.5 to about 6. The ratio between the length of the hollow tubular element and the length of the mouthpiece element may be from about 2 to about 4.

Preferably, the ratio between the length of the hollow tubular element and the length of the mouthpiece element may be approximately 3. In such an embodiment, the length of the hollow tubular element is approximately 21 mm, and the length of the mouthpiece element is approximately 7 mm.

The aerosol generating article may have an overall length of from approximately 35 millimeters to approximately 100 millimeters.

Preferably, the total length of the aerosol-generating article according to the present invention is 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.

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

In some embodiments, the overall length of the aerosol-generating article is preferably from about 38 millimeters to about 70 millimeters, more preferably from about 40 millimeters to about 70 millimeters, even more preferably from about 42 millimeters to about 70 millimeters. In other embodiments, the overall length of the aerosol-generating article is preferably from about 38 millimeters to about 60 millimeters, more preferably from about 40 millimeters to about 60 millimeters, even more preferably from about 42 millimeters to about 60 millimeters. In further embodiments, the overall length of the aerosol-generating article is preferably from about 38 millimeters to about 50 millimeters, more preferably from about 40 millimeters to about 50 millimeters, even more preferably from about 42 millimeters to about 50 millimeters. In an exemplary embodiment, the overall length of the aerosol generating article is approximately 45 millimeters.

The aerosol generating article has an external diameter of at least 5 millimeters. Preferably, the aerosol generating article has an external diameter of at least 6 millimeters. More preferably, the aerosol generating article has an external diameter of at least 7 millimeters.

Preferably, the aerosol-generating article has an outer diameter that is less than or equal to approximately 12 millimeters. More preferably, the aerosol-generating article has an outer diameter that is less than or equal to approximately 10 millimeters. Even more preferably, the aerosol-generating article has an outer diameter that is less than or equal to approximately 8 millimeters.

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

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

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

In an embodiment, the aerosol-generating substrate rod and the mouthpiece element are wrapped separately. The upstream element, the aerosol-generating substrate rod and the hollow tubular element are then combined together with the outer wrapper. Accordingly, they are combined with the mouthpiece element, which has its own wrapper, using tipping paper.

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

The term "hydrophobic" refers to a surface that exhibits water-repellent properties. One commonly used method for determining this property is by measuring the water contact angle. The "water contact angle" is the angle, typically measured by a liquid, where the liquid/vapor interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid according to Young's equation. Hydrophobicity or water contact angle can be determined using TAPPI Test Method T558 and the result is reported as the contact angle at the interface, expressed in "degrees", which can range from approximately zero to approximately 180 degrees.

In preferred embodiments, the hydrophobic wrapper is a wrapper comprising a paper layer having a water contact angle of about 30 degrees or greater, and preferably about 35 degrees or greater, or about 40 degrees or greater, or about 45 degrees or greater.

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 have a surface treatment that includes PVOH or silicon.

In a particularly preferred embodiment, the aerosol-generating article according to the present invention comprises, in a linear sequential arrangement, an upstream element, a rod of aerosol-generating substrate positioned immediately downstream of the upstream element, a hollow tubular element positioned immediately downstream of the rod of aerosol-generating substrate, a mouthpiece element positioned immediately downstream of the aerosol-cooling element, and one or more outer wrappers combining the upstream element, the rod of aerosol-generating substrate, the hollow tubular element, and the mouthpiece element. The upstream element defines an upstream section of the aerosol-generating article. The hollow tubular element and the mouthpiece element form a downstream section of the aerosol-generating article.

The aerosol-generating substrate rod may be adjacent to an upstream element. The hollow tubular element may be adjacent to the aerosol-generating substrate rod. The mouthpiece element may be adjacent to the hollow tubular element. Preferably, the hollow tubular element is adjacent to the aerosol-generating substrate rod and the mouthpiece element is adjacent to the hollow tubular element.

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

The upstream element defining the upstream section has a length of 5 millimeters, the rod of the aerosol generating article has a length of 12 millimeters, the hollow tubular element has a length of 21 millimeters, and the mouthpiece element has a length of 7 millimeters. Thus, the length of the downstream section is 28 mm, and the total length of the aerosol generating article is approximately 45 millimeters. Thus, the total length of the hollow tubular element and the mouthpiece element is 28 mm.

The element located upstream of the flow has the form of a hollow plug made of acetyl cellulose rope, which is wrapped in a rigid fiberglass.

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

In more detail, the hollow tubular member has the shape of a cardboard tube and has an internal diameter of approximately 6.7 millimeters. Thus, the thickness of the peripheral wall of the hollow tubular member is approximately 0.25 millimeters.

A ventilation zone containing an annular row of openings is provided along the hollow tubular element at a distance of 12 millimetres from the upstream end of the hollow tubular element and at a distance of 29 millimetres from the upstream end of the upstream element (or the upstream end of the aerosol generating article).

The mouthpiece is shaped as a filter segment made of low density cellulose acetate.

As discussed above, the present invention also relates to an aerosol generating system comprising an aerosol generating device having a distal end and a mouth end. The aerosol generating device may comprise a main part. The main part or casing of the aerosol generating device may define a cavity of the device for removably receiving an aerosol generating article at the mouth end of the device. The aerosol generating device may comprise a heating element or a heater for heating an aerosol generating substrate when the aerosol generating article is received within the cavity of the device.

The cavity of the device may be called the heating chamber of the aerosol generating device. The cavity of the device may extend between the distal end and the mouthpiece, or near end. The distal end of the cavity of the device may be a closed end, and the mouthpiece, or near end of the cavity of the device may be an open end. The aerosol generating article may be inserted into the cavity of the device, or the heating chamber, through the open end of the cavity of the device. The cavity of the device may have a cylindrical shape in order to match the same shape of the aerosol generating article.

The term "contained within" may refer to the fact that a component or element is contained, in whole or in part, within another component or element. For example, the term "an aerosol-generating article is contained within a cavity of a device" refers to an aerosol-generating article that is contained, in whole or in part, within a cavity of a device of an aerosol-generating article. When an aerosol-generating article is contained within a cavity of a device, the aerosol-generating article may abut a distal end of the cavity of the device. When an aerosol-generating article is contained within a cavity of a device, the aerosol-generating article may be in substantial proximity to a distal end of the cavity of the device. The distal end of the cavity of the device may be defined by an end wall.

The length of the cavity of the device may be from about 10 mm to about 50 mm. The length of the cavity of the device may be from about 20 mm to about 40 mm. The length of the cavity of the device may be from about 25 mm to about 30 mm.

The length of the cavity of the device (or heating chamber) can be the same as or greater than the length of the aerosol-generating substrate rod. The length of the cavity of the device can be the same as or greater than the total length of the upstream section or element and the aerosol-generating substrate rod. The length of the cavity of the device can be such that the downstream section or part thereof is configured to protrude from the cavity of the device when the aerosol-generating article is placed inside the cavity of the device. The length of the cavity of the device can be such that a part of the downstream section (for example, a hollow tubular element or a mouthpiece element) is configured to protrude from the cavity of the device when the aerosol-generating article is placed inside the cavity of the device. The length of the cavity of the device can be such that a part of the downstream section (for example, a hollow tubular element or a mouthpiece element) is configured to be placed inside the cavity of the device when the aerosol-generating article is placed inside the cavity of the device.

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

At least 30 percent of the length of the hollow tubular element can be inserted or accommodated within the cavity of the device when the aerosol-generating article is inserted within the device. At least 40 percent of the length of the hollow tubular element can be inserted or accommodated within the cavity of the device when the aerosol-generating article is inserted within the device. At least 50 percent of the length of the hollow tubular element can be inserted or accommodated within the cavity of the device when the aerosol-generating article is inserted within the device. Various lengths of the hollow tubular element are described in more detail in the present invention.

Optimizing the amount or length of the article inserted into the aerosol generating device can improve the resistance of the article to unintentional falling out during use. In particular, during the heating of the aerosol generating substrate, the substrate can be compressed in such a way that its outer diameter can decrease, thereby reducing the extent to which the inserted part of the article inserted into the device can engage with friction with the cavity of the device. The inserted part of the article or the part of the article configured to be contained within the cavity of the device can have the same length as the cavity of the device.

Preferably, the length of the cavity of the device is from about 25 mm to about 29 mm. More preferably, the length of the cavity of the device is from about 26 mm to about 29 mm. Even more preferably, the length of the cavity of the device is from about 27 mm to about 28 mm.

Preferably, the total length of the upstream section (or element) and the inserted portion of the downstream section or hollow tubular element is equivalent to a range of about 80 percent to about 120 percent of the length of the protruding portion of the aerosol-generating article. The inserted portion of the downstream section or hollow tubular element or aerosol-generating article refers to the portion of the downstream section or hollow tubular element or aerosol-generating article that is configured to be located within the cavity of the device when the aerosol-generating article is received therein. The protruding portion of the aerosol-generating article refers to the article that is configured to be located outside the cavity of the device or to protrude from the device when the aerosol-generating article is received therein. The inventors of the present invention have found that such a ratio minimizes the risk of the article unintentionally coming out of the device during use, especially after possible shrinkage of the article during use. The portion of the aerosol generating article adapted to be inserted into the device is preferably longer than the portion of the aerosol generating article adapted to protrude from the device when the aerosol generating article is placed inside the aerosol generating device.

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

The diameter of the cavity of the device may be substantially the same as or greater than the diameter of the aerosol-generating article. The diameter of the cavity of the device may be the same as the diameter of the aerosol-generating article to form an interference fit with the aerosol-generating article.

The cavity of the device may be configured to form a press fit with an aerosol-generating article received inside the cavity of the device. The press fit may refer to a tight fit. The aerosol-generating device may comprise a peripheral wall. Such a peripheral wall may define a cavity of the device or a heating chamber. The peripheral wall defining the cavity of the device may be configured to engage with the aerosol-generating article received inside the cavity of the device by means of a press fit, so that there is essentially no gap or empty space between the peripheral wall defining the cavity of the device and the aerosol-generating article when it is received inside the device.

Such an interference fit may create a hermetic fit or configuration between the cavity of the device and the aerosol generating article contained therein.

With such a sealed configuration, there will be essentially no gap or empty space between the peripheral wall defining the cavity of the device and the aerosol generating article for air to flow therethrough.

An interference fit with the aerosol generating article may be created along the entire length of the cavity of the device or along a portion of the length of the cavity of the device.

The aerosol generating device may comprise an air flow channel extending between the channel inlet and the channel outlet. The air flow channel may be configured to create a fluid communication between the interior of the cavity of the device and the exterior of the aerosol generating device. The air flow channel of the aerosol generating device may be defined inside the casing of the aerosol generating device to provide a fluid communication between the interior of the cavity of the device and the exterior of the aerosol generating device. When the aerosol generating article is accommodated inside the cavity of the device, the air flow channel may be configured to provide an air flow into the article to deliver the generated aerosol to the user who takes a puff through the mouth end of the article.

The air flow channel of the aerosol generating device may be defined inside the peripheral wall of the housing of the aerosol generating device, or by this peripheral wall. In other words, the air flow channel of the aerosol generating device may be defined within the thickness of the peripheral wall, or by the inner surface of the peripheral wall, or a combination of both. The air flow channel may be partially defined by the inner surface of the peripheral wall and may be partially defined within the thickness of the peripheral wall. The inner surface of the peripheral wall defines a peripheral boundary of the cavity of the device.

The air flow channel of the aerosol generating device may extend from an inlet located at the mouth end or the proximal end of the aerosol generating device to an outlet located away from the mouth end of the device. The air flow channel may extend along a direction parallel to the longitudinal axis of the aerosol generating device.

The heater may be any suitable type of heater. Preferably, in the present invention, the heater is an external heater.

Preferably, the heater can externally heat the aerosol-generating article when it is placed inside the aerosol-generating device. Such an external heater can surround the aerosol-generating article when it is inserted into the aerosol-generating device or placed inside it.

In some embodiments, the heater is arranged to heat the outer surface of the aerosol-generating substrate. In some embodiments, the heater is configured to be inserted into the aerosol-generating substrate when the aerosol-generating substrate is housed within the cavity. The heater may be arranged within the cavity of the device, or the heating chamber.

The heater may comprise at least one heating element. The at least one heating element may be a heating element of any suitable type. In some embodiments, the device comprises only one heating element. In some embodiments, the device comprises several heating elements. The heater may comprise at least one resistive heating element. Preferably, the heater comprises several resistive heating elements. Preferably, the resistive heating elements are electrically connected in a parallel arrangement. Advantageously, providing several resistive heating elements electrically connected in a parallel arrangement may facilitate the delivery of the desired electrical power to the heater, while reducing or minimizing the voltage required to provide the desired electrical power. Advantageously, reducing or minimizing the voltage required to operate the heater may help to reduce or minimize the physical size of the power supply.

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

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

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

The electrically insulating substrate may comprise any suitable material. For example, the electrically insulating substrate may comprise one or more of paper, glass, ceramic, anodized metal, coated metal, and polyimide. The ceramic may comprise mica, aluminum oxide (Al ₂ O ₃ ), or zirconium dioxide (ZrO ₂ ). Preferably, the electrically insulating substrate has a thermal conductivity that is less than or equal to about 40 watts per meter Kelvin, preferably less than or equal to about 20 watts per meter Kelvin, and ideally less than or equal to about 2 watts per meter Kelvin.

The heater may comprise a heating element comprising a rigid electrically insulating substrate with one or more electrically conductive paths or wires located on its surface. The size and shape of the electrically insulating substrate may allow it to be inserted directly into the aerosol-generating substrate. If the electrically insulating substrate is not rigid enough, the heating element may comprise additional amplifying means. Current may flow through one or more electrically conductive paths to heat the heating element and the aerosol-generating substrate.

In some embodiments, the heater comprises an induction heating device. The induction heating device may comprise an induction coil and a power supply configured to provide a high-frequency oscillating current to the induction coil. In the context of this document, "high-frequency oscillating current" means an oscillating current with a frequency of from about 500 kHz to about 30 MHz. The heater may advantageously comprise a DC-AC converter for converting a DC current supplied by a DC power supply into an AC current. The induction coil may be designed to generate a high-frequency oscillating electromagnetic field when receiving the high-frequency oscillating current from the power supply. The induction coil may be designed to generate a high-frequency oscillating electromagnetic field in a cavity of the device. In some embodiments, the induction coil may substantially surround the cavity of the device. The induction coil may extend at least partially along the length of the cavity of the device.

The heater may comprise an induction heating element. The induction heating element may be a current collector. In the context of this document, the term "current collector" refers to an element comprising a material that is capable of converting electromagnetic energy into heat. When the current collector is placed in an alternating electromagnetic field, the current collector heats up. The heating of the current collector may be the result of at least one of hysteresis losses and eddy currents induced in the current collector, depending on the electrical and magnetic properties of the current collector material.

The current-receiving element can be arranged so that when the aerosol-generating article is accommodated in the cavity of the aerosol-generating device, the oscillating electromagnetic field generated by the induction coil induces a current in the current-receiving element, which results in heating of the current-receiving element. In these embodiments, the aerosol-generating device is preferably capable of generating a fluctuating electromagnetic field having a magnetic field strength (field strength H) of 1 to 5 kiloamperes per meter (kA/m), preferably 2 to 3 kA/m, for example approximately 2.5 kA/m. The electrical aerosol-generating device 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.

In these embodiments, the current-receiving element is preferably placed in contact with the aerosol-forming substrate. In some embodiments, the current-receiving element is placed in the aerosol-generating device. In these embodiments, the current-receiving element may be placed in a cavity. The aerosol-generating device may contain only one current-receiving element. The aerosol-generating device may contain several current-receiving elements. In some embodiments, the current-receiving element is preferably positioned so as to heat the outer surface of the aerosol-forming substrate.

The current collecting element may comprise any suitable material. The current collecting 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 the elongated current collecting element include graphite, molybdenum, silicon carbide, stainless steels, niobium, aluminum, nickel, nickel compounds, titanium, and composites of metallic materials. Some current collecting elements comprise metal or carbon. Advantageously, the current collecting element may comprise or consist of a ferromagnetic material, such as ferritic iron, a ferromagnetic alloy such as ferromagnetic steel or stainless steel, ferromagnetic particles, and ferrite. A suitable current collecting element may be made of or comprise aluminum. The current collecting element preferably comprises more than about 5 percent, preferably more than about 20 percent, more preferably more than about 50 percent or more than about 90 percent of ferromagnetic or paramagnetic materials. Some elongated current collecting elements can be heated to a temperature in excess of about 250 degrees Celsius.

The current collecting element may comprise a non-metallic core with a metallic layer located on the non-metallic core. For example, the current collecting element may comprise metallic tracks formed on the outer surface of a ceramic core or substrate.

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

During use, the heater can be controlled to operate in a certain range of operating temperatures below the maximum operating temperature. The preferred operating temperature range is from about 150 degrees Celsius to about 300 degrees Celsius in the heating chamber (or cavity of the device). The operating temperature range of the heater can be from about 150 degrees Celsius to about 250 degrees Celsius.

Preferably, the operating temperature range of the heater may be from about 150 degrees Celsius to about 200 degrees Celsius. More preferably, the operating temperature range of the heater may be from about 180 degrees Celsius to about 200 degrees Celsius. In particular, it has been found that optimal and stable aerosol delivery can be achieved by using an aerosol generating device having an external heater that has an operating temperature range of from about 180 degrees Celsius to about 200 degrees Celsius, wherein the aerosol generating articles have a relatively low RTD (for example, the RTD of the downstream section is less than 15 mm H2O), as mentioned in the present invention.

In embodiments where the aerosol-generating article comprises a ventilation zone at a location along a downstream section or a hollow tubular element, the ventilation zone may be arranged so as to be open when the aerosol-generating article is housed within the cavity of the device. Thus, the length of the cavity of the device or the 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 housed 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.

When the article is placed inside the cavity of the device, the ventilation zone can be located at a distance of at least 0.5 mm (in the direction downstream of the article) from the mouth end (or the surface of the mouth end) of the cavity of the device or the device itself. When the article is placed inside the cavity of the device, the ventilation zone can be located at a distance of at least 1 mm (in the direction downstream of the article) from the mouth end (or the surface of the mouth end) of the cavity of the device or the device itself. When the article is placed inside the cavity of the device, the ventilation zone can be located at a distance of at least 2 mm (in the direction downstream of the article) from the mouth end (or the surface of the mouth end) of the cavity of the device or the device itself.

Preferably, the ratio between the distance between the ventilation zone and the upstream end of the upstream element and the length of the heating chamber is from approximately 1.03 to approximately 1.13.

This arrangement of the ventilation zone ensures that the ventilation zone is not blocked within the cavity of the device itself, while minimizing the risk of blocking by the lips or hands of the user, since the ventilation zone is located in a position as far upstream as possible relative to the end of the product located further downstream, without being blocked within the cavity of the device.

The aerosol generating device may comprise 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, such as a lithium-cobalt, lithium-iron phosphate, or lithium-polymer battery. However, in some embodiments, the power supply may be another type of charge storage device, such as a capacitor. The power supply may require recharging and may have a capacity that allows storing enough energy for one or more user operations, such as one or more aerosol generation sessions. For example, the power supply may have sufficient capacity to ensure continuous heating of the aerosol generating substrate for a period of approximately six minutes, which corresponds to the typical time required to smoke a conventional cigarette, or for a period that is a multiple of six minutes. In another example, the power supply may have sufficient capacity to enable a specified number of puffs or individual heater activations.

The following is a non-exhaustive list of non-limiting examples. Any one or more features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

EX1. An aerosol generating article comprising: a rod of aerosol generating substrate; and a downstream section provided downstream of the rod of aerosol generating substrate, wherein the downstream section comprises at least one hollow tubular element.

EX2. An aerosol generating article according to example EX1, further comprising an upstream section provided upstream of the aerosol generating substrate rod, wherein the upstream section comprises at least one upstream element.

EX3. An aerosol generating article according to example EX2, wherein the upstream element has a length of between 2 millimetres and 8 millimetres.

EX4. An aerosol generating article according to example EX2 or EX3, wherein the upstream element is formed from a hollow tubular segment defining a longitudinal cavity providing a channel for unrestricted flow.

EX5. An aerosol generating article according to example EX4, wherein the longitudinal cavity of the hollow tubular segment has a diameter of at least 5 millimetres.

EX6. An aerosol generating article according to example EX4 or EX5, wherein the hollow tubular segment has a wall thickness of less than 1 millimetre.

EX7. An aerosol generating article according to any of EX2-EX6, wherein the upstream element has a resistance to draw (RTD) of less than 2 mm H2O.

EX8. An aerosol generating article according to any of the examples EX2-EX7, wherein the upstream end of the upstream element defines the upstream end of the aerosol generating article.

EX9. An aerosol generating article according to any preceding example, further comprising a ventilation zone.

EX10. An aerosol generating article according to example EX9, wherein the ventilation zone is provided at a location along the hollow tubular element of the downstream section.

EX11. An aerosol generating article according to example EX9 or EX10, wherein the ventilation zone is provided at a distance of from 26 millimetres to 33 millimetres from the upstream end of the article.

EX12. An aerosol generating article according to example EX9 or EX10, wherein the ventilation zone is provided at a distance of from 27 millimetres to 31 millimetres from the upstream end of the article.

EX13. An aerosol generating article according to any of EX9-EX12, wherein the ventilation zone is provided at a distance of from 12 millimetres to 20 millimetres from the downstream end of the article.

EX14. An aerosol generating article according to any of the examples EX9-EX13, wherein the ventilation zone is provided at least 10 millimeters downstream of the downstream end of the aerosol generating substrate rod.

EX15. An aerosol generating article according to any preceding example, wherein the hollow tubular member of the downstream section has a length of between 17 millimetres and 25 millimetres.

EX16. An aerosol generating article according to any preceding example, wherein the hollow tubular element of the downstream section has an internal volume of at least 300 cubic millimeters.

EX17. An aerosol generating article according to any preceding example, wherein the aerosol generating substrate rod has a length of between 8 millimeters and 16 millimeters.

EX18. An aerosol generating article according to any preceding example, wherein the aerosol generating substrate rod has a resistance to draw (RTD) of from 4 mm H2O to 10 mm H2O.

EX19. An aerosol-generating article according to any preceding example, wherein the aerosol-generating substrate comprises shredded tobacco material.

EX20. An aerosol generating article according to example EX19, wherein the shredded tobacco material has an average density of from 150 milligrams per cubic centimeter to 500 milligrams per cubic centimeter.

EX21. An aerosol-generating article according to any preceding example, wherein the aerosol-generating substrate comprises one or more aerosol-forming substances, and wherein the content of the aerosol-forming substance in the aerosol-generating substrate is from 10 percent to 20 percent by weight on a dry weight basis.

EX22. An aerosol generating article according to example EX19, wherein the aerosol forming substance comprises one or more of glycerol and propylene glycol.

EX23. An aerosol-generating article according to any preceding example, wherein the aerosol-generating substrate comprises tobacco shredded filler.

EX24. An aerosol generating article according to any preceding example, wherein the downstream section further comprises a mouthpiece element.

EX25. An aerosol generating article according to example EX24, wherein the mouthpiece element comprises at least one mouthpiece filter segment formed from a fibrous filter material.

EX26. An aerosol generating article according to example EX24 or EX25, wherein the length of the mouthpiece element is from 3 millimetres to 11 millimetres.

EX27. An aerosol generating article according to any of EX24-EX26, wherein the mouthpiece has a resistance to draw (RTD) of from 4 mm H2O to 11 mm H2O.

EX28. An aerosol generating article according to any of EX24-EX27, wherein the combined length of the hollow tubular member and the mouthpiece of the downstream section is between 24 millimeters and 32 millimeters.

EX29. An aerosol-generating article according to any preceding example, wherein the resistance to draw (RTD) of the article is between 20 mmH2O and 22 mmH2O.

EX30. An aerosol generating article according to any preceding example, wherein the outside diameter of the article is substantially uniform along its length.

EX31. An aerosol-generating article according to any preceding example, wherein the ventilation rate of the aerosol-generating article is between 10 percent and 30 percent.

EX32. An aerosol-generating article according to any preceding example, where

EX33. An aerosol generating system comprising an aerosol generating article according to any of the previous examples and an aerosol generating device comprising a heating chamber for containing the aerosol generating article and at least a heating element provided at or around the periphery of the heating chamber.

The present invention will now be further described with reference to the accompanying drawings, in which:

Fig. 1 is a schematic side perspective view of an aerosol generating article according to an embodiment of the present invention;

Fig. 2 is a schematic side sectional view of an aerosol generating article according to an embodiment of the present invention; and

Fig. 3 is a schematic side sectional view of an aerosol generating system comprising an aerosol generating article according to an embodiment of the present invention and an aerosol generating device.

The aerosol generating article 10 shown in Fig. 1 comprises a rod of aerosol generating substrate 12 and a downstream section 14 at a location downstream of the rod 12 of the aerosol generating substrate. Thus, the aerosol generating article 10 extends from an upstream or distal end 16, which substantially coincides with the upstream end of the rod 12, to a downstream or mouth end 18, which coincides with the downstream end of the downstream section 14. The downstream section 14 comprises a hollow tubular element 20 and a mouthpiece element 50.

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

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 percent by weight to 16 percent by weight of glycerol. 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 6-8 mm H2O. The aerosol generating substrate rod 12 is individually wrapped in a wick (not shown). The wick (not shown) that wraps the aerosol generating substrate rod comprises non-porous paper having a square meter weight of approximately 25 grams per square meter (gsm) and a thickness of approximately 40 micrometers.

The hollow tubular element 20 is positioned immediately downstream of the aerosol-generating substrate rod 12, wherein the hollow tubular element 20 is in longitudinal alignment with the rod 12. The upstream end of the hollow tubular element 20 is adjacent to the downstream end of the aerosol-generating substrate rod 12.

The hollow tubular element 20 defines a hollow section of the aerosol generating article 10. The hollow tubular element does not substantially affect the overall RTD of the aerosol generating article. In more detail, the RTD of the hollow tubular element 20 is approximately 0 mm H2O.

As shown in Fig. 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 over the entire distance 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 a substantially unimpeded flow of air through the internal cavity 22 is possible. The hollow tubular element 20 does not substantially affect the overall RTD of the aerosol-generating article 10.

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. Thus, the thickness of the peripheral wall of the hollow tubular element 20 is approximately 0.25 millimeters.

The aerosol generating article 10 comprises a ventilation zone 30 provided at a location along the hollow tubular element 20. In more detail, the ventilation zone 30 is provided at a distance of approximately 16 millimeters from the downstream end 18 of the article 10. The ventilation zone 30 is provided at a distance of approximately 12 mm downstream from the downstream end of the aerosol generating substrate rod 12. The ventilation zone 30 is provided at a distance of approximately 9 mm upstream of the upstream end of the mouthpiece element 50. The ventilation zone 30 comprises an annular row of openings or perforations surrounding the hollow tubular element 20. The perforations of the ventilation zone 30 pass through the wall 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 approximately 16 percent.

Above the rod 12 of the aerosol generating substrate and the downstream section 14 at a location downstream of the rod 12, the aerosol generating article 100 comprises an upstream section 40 at a location 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.

The upstream section 40 comprises an upstream element 42 positioned immediately upstream of the aerosol-generating substrate rod 12, wherein the upstream element 42 is in longitudinal alignment with the rod 12. The downstream end of the upstream element 42 is adjacent to the upstream end of the aerosol-generating substrate rod 12. The upstream element 42 is provided in the form of a hollow cylindrical plug made of cellulose acetate tow having a wall thickness of approximately 1 mm and defining an internal cavity 23. The upstream element 42 has a length of approximately 5 millimetres. The outer diameter of the upstream element 42 is approximately 7.1 mm. The inner diameter of the upstream element 42 is approximately 5.1 mm.

The mouthpiece element 50 extends from the downstream end of the hollow tubular element 20 to the downstream or mouthpiece end of the aerosol generating article 10. The mouthpiece element 50 has a length of approximately 7 mm. The outer diameter of the mouthpiece element 50 is approximately 7.2 mm. The mouthpiece element 50 comprises a low density cellulose acetate filter segment. The RTD of the mouthpiece element 50 is approximately 8 mm H2O. The mouthpiece element 50 may be individually wrapped with a filament (not shown).

As shown in Fig. 1 and 2, the article 10 comprises an upstream wrapper 44 surrounding an upstream element 42, an aerosol generating substrate 12, and a hollow tubular element 20. The ventilation zone 30 may also comprise an annular row of perforations provided on the upstream wrapper 44. The perforations of the upstream wrapper 44 overlap the perforations provided on the hollow tubular element 20. Accordingly, the upstream wrapper 44 overlaps the perforations of the ventilation zone 30 provided on the hollow tubular element 20.

The article 10 also comprises a rim wrap 52 that encloses the hollow tubular element 20 and the mouthpiece element 50. The rim wrap 52 overlaps a portion of the upstream wrap 44 that overlaps the hollow tubular element 20. Thus, the rim wrap 52 effectively connects the mouthpiece element 50 to the remaining components of the article 10. The width of the rim wrap 52 is approximately 26 mm. Additionally, the ventilation zone 30 may comprise an annular row of perforations provided on the rim wrap 52. The perforations of the rim wrap 52 overlap the perforations provided on the hollow tubular element 20 and the wrap 44 located upstream. Accordingly, the rim wrap 52 overlaps the perforations of the ventilation zone 30 provided on the hollow tubular element 20 and the wrap 44 located upstream.

Fig. 3 shows an aerosol generating system 100, comprising an illustrative aerosol generating device 1 and an aerosol generating article 10, equivalent to that shown in Figs. 1 and 2. Fig. 3 shows a downstream portion of the mouthpiece end of the aerosol generating device 1, where a cavity of the device is defined and can accommodate the aerosol generating article 10. The aerosol generating device 1 comprises a housing (or main part) 4, extending between the mouthpiece end 2 and a distal end (not shown). The housing 4 comprises a peripheral wall 6. The peripheral wall 6 defines a cavity of the device for receiving the aerosol generating article 10. The cavity of the device is defined by a closed distal end and an open mouthpiece end. The mouthpiece end of the cavity of the device is located on the mouthpiece end of the aerosol-generating device 1. The aerosol-generating article 10 is designed with the possibility of being contained through the mouthpiece end of the cavity of the device and is designed with the possibility of adjoining the closed end of the cavity of the device.

An air flow channel 5 of the device is defined inside the peripheral wall 6. The air flow channel 5 extends between the inlet opening 7 located at the mouth end of the aerosol generating device 1 and the closed end of the cavity of the device. Air can enter the aerosol generating substrate 12 through an opening (not shown) provided at the closed end of the cavity of the device, providing fluid communication between the air flow channel 5 and the aerosol generating substrate 12.

The aerosol generating device 1 further comprises a heater (not shown) and a power source (not shown) for supplying power to the heater. A controller (not shown) is also provided for controlling such power supply to the heater. The heater is configured to controllably heat the aerosol generating article 10 during use, when the aerosol generating article 1 is housed inside the device 1. The heater is preferably configured to externally heat the aerosol generating substrate 12 for optimal aerosol generation. The ventilation zone 30 is arranged to be open, when the aerosol generating article 10 is housed inside the aerosol generating device 1.

In the embodiment shown in Fig. 3, the cavity of the device defined by the peripheral wall 6 has a length of 28 mm. When the article 10 is received inside the cavity of the device, the upstream section 40, the rod of the aerosol generating substrate 12 and the upstream portion of the hollow tubular element 20 are received inside the cavity of the device. The length of such upstream portion of the hollow tubular element 20 is 11 mm. Accordingly, approximately 28 mm of the article 10 is received inside the device 1, and approximately 17 mm of the article 10 is located outside the device 1. In other words, approximately 17 mm of the article 10 projects from the device 1 when the article 10 is received in it. Such a length PL of the article 10 projecting from the device 1 is shown in Fig. 3.

As a result, the ventilation zone 30 is preferably located outside the device 1 when the article 10 is inserted into the device 1. If the cavity of the device has a length of 28 mm, the ventilation zone 30 is located at a distance of 1 mm downstream from the mouthpiece end 2 of the device 1 when the article 10 is placed inside the device 1. For the purposes of the present description and the appended claims, except where otherwise indicated, all numbers expressing quantities, amounts, percentages, etc., are to be understood as modified in all cases by the term "about". Also, all ranges include the disclosed maximum and minimum points and include any intermediate ranges therebetween that may or may not be specifically listed herein. Therefore, in this context, the number A is understood to be A ± 10% of A. In this context, the number A may be considered to include numerical values that are within the common standard error for the measurement of the property that the number A modifies. The number A, in some cases, when used in the appended claims, may vary by the percentages listed above, provided that the amount by which A varies does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the disclosed maximum and minimum points and include any intermediate ranges therebetween that may or may not be specifically listed herein.

Claims (19)

1. An aerosol generating article comprising: a rod of aerosol generating substrate, having a length of 8 mm to 16 mm; an upstream element provided upstream of the aerosol generating substrate rod, wherein the upstream element has an outer diameter of 6 mm to 8 mm; a hollow tubular element provided downstream of the aerosol generating substrate rod, wherein the internal volume defined by the hollow tubular element is at least 300 cubic millimetres; and a ventilation zone for providing ventilation in the aerosol-generating article, wherein the ventilation zone is located at a distance of 12 mm to 20 mm upstream of the said downstream end of the aerosol-generating article. 2. An aerosol generating article according to paragraph 1, characterized in that the ventilation zone is provided in a location along the hollow tubular element. 3. An aerosol-generating article according to claim 1 or 2, characterized in that the ventilation zone is located at a distance of 14 mm to 18 mm upstream of the flow relative to the said end of the aerosol-generating article located further downstream. 4. An aerosol generating article according to any of the preceding claims, characterized in that the ventilation zone is located at a distance of at least 10 mm downstream of said downstream end of the aerosol generating substrate rod. 5. An aerosol generating article according to any of the preceding paragraphs, characterized in that said element located upstream of the flow has a length of from 2 mm to 8 mm. 6. An aerosol generating article according to any of the preceding claims, characterized in that the wall thickness of the hollow tubular element is at least 0.1 mm. 7. An aerosol generating article according to any of the preceding paragraphs, characterized in that the wall thickness of the hollow tubular element is no more than 2 mm. 8. An aerosol generating article according to any of the preceding claims, characterized in that the hollow tubular element consists of a continuous hollow tubular segment. 9. An aerosol generating article according to any of the preceding claims, characterized in that the length of the hollow tubular element is at least 15 mm. 10. An aerosol-generating article according to any one of the preceding claims, characterized in that the aerosol-generating substrate contains one or more aerosol-forming substances, and wherein the content of the aerosol-forming substance in the aerosol-forming substrate is at least 10 percent by weight, calculated on a dry weight basis. 11. An aerosol-generating article according to any of the preceding claims, characterized in that the aerosol-generating substrate comprises shredded tobacco material. 12. An aerosol-generating article according to paragraph 11, characterized in that the crushed tobacco material has a density of 150 milligrams per cubic centimeter to 500 milligrams per cubic centimeter. 13. An aerosol generating article according to any of the preceding paragraphs, characterized in that the aerosol generating article additionally comprises a mouthpiece element located further downstream of the hollow tubular element. 14. An aerosol generating system comprising an aerosol generating article according to any one of the preceding claims and an aerosol generating device comprising a heating chamber for containing the aerosol generating article and at least a heating element provided at or around the periphery of the heating chamber. 15. An aerosol generating system according to claim 14, characterized in that when the aerosol generating article is placed inside the aerosol generating device, the distance between the ventilation zone and the upstream end of the upstream element is greater than the length of the heating chamber.