CN118973416A - Aerosol-generating article having an upstream component - Google Patents

Abstract

An aerosol-generating article is provided. The aerosol-generating article comprises a strip of aerosol-generating substrate and a downstream section disposed downstream of the strip of aerosol-generating substrate and extending to a downstream end of the aerosol-generating article. The downstream section includes hollow tubular cooling elements and has a length greater than 45 millimeters. The aerosol-generating article further comprises an upstream element arranged upstream of the strip of aerosol-generating substrate. The upstream element is adjacent to an upstream end of the strip of aerosol-generating substrate and has a length of at least 3 mm.

Description

Aerosol-generating article having an upstream component

The present invention relates to an aerosol-generating article comprising an aerosol-generating substrate and adapted to generate an inhalable aerosol upon heating.

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

Many prior art documents disclose aerosol generating devices for consuming aerosol generating articles. Such devices include, for example, electrically heated aerosol generating devices, in which an aerosol is generated by transferring heat from one or more electric heater elements of the aerosol generating device to an aerosol generating substrate of a heated aerosol generating article. For example, electrically heated aerosol generating devices including internal heater blades have been proposed, and the internal heater blades are suitable for being inserted into the aerosol generating substrate. It is also known to use aerosol generating articles in combination with external heating systems. For example, WO2020/115151 describes the provision of one or more heating elements arranged around the periphery of the aerosol generating article when the aerosol generating article is received in the cavity of the aerosol generating device. As an alternative, an inductively heatable aerosol generating article is proposed by WO2015/176898, which includes an aerosol generating substrate and a receptor arranged in the aerosol generating substrate.

Aerosol generation articles wherein the substrate containing tobacco is heated and not burnt present many challenges that conventional smoking articles have not encountered.First, compared with the temperature reached by the combustion front in conventional cigarettes, the substrate containing tobacco is usually heated to a significantly lower temperature.This may affect the nicotine release of the substrate containing tobacco and deliver nicotine to the consumer.Meanwhile, if the heating temperature increases in an attempt to strengthen nicotine delivery, the generated aerosol usually needs to cool to a greater extent and faster before it arrives at the consumer.However, the technical solution (such as providing high filtration efficiency sections at the mouth end of cigarette) that is usually used to cool the mainstream smoke in conventional smoking articles may have undesirable effects in the aerosol generation articles wherein the substrate containing tobacco is heated and not burnt, because they can reduce the delivery of nicotine.Therefore, it is desirable to provide a novel aerosol generation article that can consistently ensure that a satisfactory aerosol delivery is provided to the consumer.

In addition, there is a generally recognized need for an aerosol-generating article that is easy to use and has improved utility. For example, it is desirable to provide an aerosol-generating article that can be easily inserted into the heating cavity of an aerosol-generating device, and at the same time can be securely retained within the heating cavity so that it does not slip out during use.

It would also be desirable to provide an aerosol-generating article that is adapted such that an aerosol-generating substrate can be heated more efficiently when the aerosol-generating article is inserted into a heating chamber of an aerosol-generating device, thereby minimizing waste of tobacco material.

The present disclosure relates to an aerosol generating article. The aerosol generating article may include a strip of an aerosol generating substrate. The aerosol generating article may include a downstream section, which is disposed downstream of the strip of the aerosol generating substrate and extends to the downstream end of the aerosol generating article. The downstream section may include a hollow tubular cooling element. The downstream section may have a length of at least 45 mm. The aerosol generating article may also include an upstream element, which is disposed upstream of the strip of the aerosol generating substrate. The upstream element may be adjacent to the upstream end of the strip of the aerosol generating substrate.

According to the present invention, an aerosol generating article is provided, comprising: a strip of an aerosol generating substrate; a downstream section, which is arranged downstream of the strip of the aerosol generating substrate and extends to the downstream end of the aerosol generating article, wherein the downstream section comprises a hollow tubular cooling element, and wherein the downstream section has a length of at least 45 mm; and an upstream element, which is arranged upstream of the strip of the aerosol generating substrate and is adjacent to the upstream end of the strip of the aerosol generating substrate.

The present invention relates to an aerosol generating article which provides a combination of an upstream element and a relatively long downstream section having a length of at least 45 mm, which is significantly longer than the downstream sections of aerosol generating articles of the prior art. This combination of features enables the length of the strip of aerosol generating substrate to be reduced while maintaining the overall length of the aerosol generating article. The position of the strip of aerosol generating substrate can also be maintained as much as possible so that the placement of the strip of aerosol generating substrate in the heating chamber of the aerosol generating device is not significantly affected. Therefore, the inclusion of the upstream element has a minimal effect on the generation of aerosol from the strip of aerosol generating substrate during use.

It may be desirable to have a strip of aerosol generating substrate with a reduced length, for example in order to maximize the proportion of the strip of aerosol generating substrate that is heated when the aerosol generating article is inserted into the heating chamber of the aerosol generating device. This in turn optimizes the efficiency of generating aerosols from the strip of aerosol generating substrate, so that the amount of aerosol generating substrate can be minimized as much as possible without affecting the generation of aerosols. The amount of aerosol generating substrate that is actually wasted because it is not used to generate aerosols can also be minimized. However, it may also be important to maintain the overall length of the aerosol generating article so that the article can continue to be used in combination with existing aerosol generating devices. Equally important, existing machines and packaging can also be used without modification.

It may also be desirable to provide an aerosol-generating article having a relatively long overall length, as this may improve anchoring of the aerosol-generating article within the heating chamber of the aerosol-generating device and may provide improvements in the mechanical integrity of the article.

Additionally, due to the increased length of the downstream section, the relatively long overall length of the aerosol-generating article means that aerosol-generating articles according to the invention more closely resemble combustible cigarettes, which may be attractive to consumers.

In the aerosol generating article of the present invention, providing a relatively long downstream section increases the available distance and time, in which the aerosol can be cooled downstream of the strip of aerosol generating substrate. Therefore, the aerosol can be cooled more effectively before being delivered to the consumer. For example, in a preferred embodiment, the increase in the length of the downstream section enables the inclusion of a relatively long hollow tubular cooling element, thereby optimizing the cooling provided in the downstream section due to the increase in the length and volume of the inner cavity along which the aerosol travels during use. This may be particularly advantageous for embodiments in which the aerosol generating article has a reduced outer diameter (e.g., the article has a maximum outer diameter of less than 7 mm). In such articles, it has been found that a reduction in the diameter of the hollow tubular cooling element reduces the effectiveness of cooling due to a reduction in surface area and volume. Therefore, in order to ensure that the aerosol is delivered to the consumer at an acceptable temperature, the additional length provided by the longer downstream section is particularly important.

Including an upstream element in an aerosol generating article according to the present invention also advantageously provides additional benefits. Before use, the upstream element prevents loose particles of an aerosol generating substrate such as tobacco material from being lost from the upstream end of the strip. This may be particularly advantageous in embodiments in which the strip of the aerosol generating substrate comprises shredded tobacco material (such as shredded filler). The presence of the upstream element may also enable the use of shredded tobacco material of lower density, which, due to its looser packaging in the strip, will have a higher risk of falling from the aerosol generating article.

During use of the aerosol-generating article, providing an upstream element in abutting relation to the substrate can advantageously provide for retention of any condensed aerosol formed within the article during use, such that it is contained within the article and substantially prevented from leaking. It has been found that the condensed aerosol is naturally drawn towards the upstream element during use due to capillary action. The condensate is then typically retained within the upstream element by means of surface tension or absorption.

Furthermore, providing an upstream element may improve the mechanical robustness of the upstream end of the aerosol-generating article and facilitate insertion of the upstream end of the aerosol-generating article into the cavity of the heating device. It may also protect the upstream end of the strip of aerosol-generating substrate during insertion. Once the aerosol-generating article is inserted into the cavity of the heating device, the upstream element may help anchor the article inside the cavity so that it does not slip out during use.

Additionally, the resistance to draw (RTD) of the upstream element may be easily adjusted to take into account variations in the RTD levels of the strips and downstream segments of the aerosol generating substrate, which may be due to variations in their length (or density in the case of strips of aerosol generating substrate). Variations in the RTD of the upstream element may advantageously be made without affecting the generation of the aerosol, since this occurs downstream of the upstream element.

The aerosol generating article according to the present invention comprises a strip of an aerosol generating substrate. In addition, the aerosol generating article according to the present invention comprises one or more elements arranged downstream of the aerosol generating substrate. Where present, the one or more elements downstream of the strip of the aerosol generating substrate form a downstream section of the aerosol generating article. The aerosol generating article according to the present invention may comprise one or more elements arranged upstream of the aerosol generating substrate. Where present, the one or more elements upstream of the strip of the aerosol generating substrate form an upstream section of the aerosol generating article.

The strip of aerosol-generating substrate is preferably defined by a wrapper such as a stick wrapper.

The strip of aerosol generating substrate preferably has a length of at least 10 millimeters. Preferably, the strip of aerosol generating substrate has a length of at least 15 millimeters. More preferably, the strip of aerosol generating substrate has a length of at least 17 millimeters. Even more preferably, the strip of aerosol generating substrate has a length of at least 18 millimeters. Most preferably, the strip of aerosol generating substrate has a length of at least 20 millimeters.

The strip of aerosol-generating substrate preferably has a length of less than 40 mm. Preferably, the strip of aerosol-generating substrate has a length of less than 35 mm. More preferably, the strip of aerosol-generating substrate has a length of less than 30 mm.

For example, the strip of aerosol generating substrate preferably has a length between 10 mm and 40 mm, or between 10 mm and 35 mm, or between 10 mm and 30 mm, or between 15 mm and 40 mm, or between 15 mm and 35 mm, or between 15 mm and 30 mm, or between 20 mm and 40 mm, or between 20 mm and 35 mm, or between 20 mm and 30 mm.

The strip of aerosol-generating substrate preferably has an outer diameter substantially equal to the outer diameter of the aerosol-generating article.

The "outer diameter of the stripe of aerosol-generating substrate" may be calculated as the average of a plurality of measurements of the diameter of the stripe of aerosol-generating substrate taken at different positions along the length of the stripe of aerosol-generating substrate.

Preferably, the strip of aerosol-generating substrate has an outer diameter of at least about 5 mm. More preferably, the strip of aerosol-generating substrate has an outer diameter of at least 5.25 mm. Even more preferably, the strip of aerosol-generating substrate has an outer diameter of at least 5.5 mm.

The strip of aerosol-generating substrate preferably has an outer diameter of less than 8 mm. More preferably, the strip of aerosol-generating substrate has an outer diameter of less than 7.5 mm. Even more preferably, the strip of aerosol-generating substrate has an outer diameter of less than 7 mm.

In general, it has been observed that the smaller the diameter of the strip of aerosol generating substrate, the lower the temperature required to raise the core temperature of the strip of aerosol generating substrate so as to release a sufficient amount of vaporizable substance from the aerosol generating substrate to form a desired amount of aerosol. At the same time, without wishing to be bound by theory, it should be understood that the smaller diameter of the strip of aerosol generating substrate allows the heat supplied to the aerosol generating article to penetrate more quickly into the entire volume of the aerosol generating substrate. However, in the case where the diameter of the strip of aerosol generating substrate is too small, the volume to surface ratio of the aerosol generating substrate becomes less favorable because the amount of available aerosol generating substrate is reduced.

The diameter of the strip of aerosol-generating substrate falling within the range described herein is particularly advantageous in terms of the balance between energy consumption and aerosol delivery. This advantage is felt when the aerosol-generating article including the strip of aerosol-generating substrate with a diameter as described herein is used in combination with an external heater arranged around the periphery of the aerosol-generating article. Under such operating conditions, it has been observed that at the core of the strip of aerosol-generating substrate, and generally at the core of the article, less heat energy is required to achieve a sufficiently high temperature. Therefore, when operating at a lower temperature, the desired target temperature at the core of the aerosol-generating substrate can be achieved within the desired reduced time range and by lower energy consumption.

The use of rods of aerosol-generating substrates having a smaller diameter may also advantageously reduce the overall weight of tobacco material required in an aerosol-generating article, whilst still being able to generate a desired level of aerosol.Thus, levels of tobacco waste may be reduced.

The ratio between the length of the strip of aerosol-generating substrate and the overall length of the aerosol-generating article is preferably at least 0.20. Preferably, the ratio between the length of the strip of aerosol-generating substrate and the overall length of the aerosol-generating article is at least 0.25. More preferably, the ratio between the length of the strip of aerosol-generating substrate and the overall length of the aerosol-generating article is at least 0.30.

The ratio between the length of the strip of aerosol-generating substrate and the overall length of the aerosol-generating article is preferably less than 0.50. Preferably, the ratio between the length of the strip of aerosol-generating substrate and the overall length of the aerosol-generating article is less than 0.45. More preferably, the ratio between the length of the strip of aerosol-generating substrate and the overall length of the aerosol-generating article is less than 0.40.

In some embodiments, the ratio between the length of the strip of the aerosol generating substrate and the overall length of the aerosol generating article is 0.20 to 0.50, preferably 0.20 to 0.45, and more preferably 0.20 to 0.40. In other embodiments, the ratio between the length of the strip of the aerosol generating substrate and the overall length of the aerosol generating article is 0.25 to 0.50, preferably 0.25 to 0.45, and more preferably 0.25 to 0.40. In other embodiments, the ratio between the length of the strip of the aerosol generating substrate and the overall length of the aerosol generating article is 0.30 to 0.50, preferably 0.30 to 0.45, and more preferably 0.30 to 0.40. In some other embodiments, the ratio between the length of the strip of the aerosol generating substrate and the overall length of the aerosol generating article is 0.30 to 0.50, preferably 0.30 to 0.45, and more preferably 0.30 to 0.40.

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

Preferably, the density of the aerosol-generating substrate is at least 100 mg/cm3. More preferably, the density of the aerosol-generating substrate is at least 125 mg/cm3. More preferably, the density of the aerosol-generating substrate is at least 150 mg/cm3. Even more preferably, the density of the aerosol-generating substrate is at least 200 mg/cm3.

Preferably, the density of the aerosol generating substrate is less than 1000 mg/cm3. More preferably, the density of the aerosol generating substrate is less than 800 mg/cm3. More preferably, the density of the aerosol generating substrate is less than 700 mg/cm3. More preferably, the density of the aerosol generating substrate is less than 600 mg/cm3. More preferably, the density of the aerosol generating substrate is less than 500 mg/cm3. More preferably, the density of the aerosol generating substrate is less than 400 mg/cm3. More preferably, the density of the aerosol generating substrate is less than 350 mg/cm3. More preferably, the density of the aerosol generating substrate is less than 345 mg/cm3. More preferably, the density of the aerosol generating substrate is less than 325 mg/cm3. More preferably, the density of the aerosol generating substrate is less than 300 mg/cm3. More preferably, the density of the aerosol generating substrate is less than 290 mg/cm3. Even more preferably, the density of the aerosol-generating substrate is less than 280 mg/cm3.

For example, the density of the aerosol generating substrate is preferably 100 mg/cm3 to 1000 mg/cm3, preferably 100 mg/cm3 to 800 mg/cm3, more preferably 100 mg/cm3 to 700 mg/cm3, more preferably 100 mg/cm3 to 600 mg/cm3, more preferably 100 mg/cm3 to 500 mg/cm3, and even more preferably 100 mg/cm3 to 400 mg/cm3.

For example, the density of the aerosol generating substrate is preferably 100 mg/cm3 to 350 mg/cm3, preferably 100 mg/cm3 to 345 mg/cm3, preferably 125 mg/cm3 to 325 mg/cm3, more preferably 150 mg/cm3 to 300 mg/cm3, more preferably 150 mg/cm3 to 290 mg/cm3, and even more preferably 200 mg/cm3 to 280 mg/cm3.

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

Preferably, tobacco material has a bulk density of at least 100mg/ cubic centimeter. More preferably, tobacco material has a bulk density of at least 125mg/ cubic centimeter. More preferably, tobacco material has a bulk density of at least 150mg/ cubic centimeter. Even more preferably, tobacco material has a bulk density of at least 200mg/ cubic centimeter. Preferably, tobacco material has a bulk density less than 345mg/ cubic centimeter. More preferably, tobacco material has a bulk density less than 325mg/ cubic centimeter. Even more preferably, tobacco material has a bulk density less than 300mg/ cubic centimeter. Even more preferably, tobacco material has a bulk density less than 290mg/ cubic centimeter. Even more preferably, tobacco material has a bulk density less than 280mg/ cubic centimeter. For example, the tobacco material may have a bulk density of 100 mg/cm3 to 350 mg/cm3, preferably 100 mg/cm3 to 345 mg/cm3, more preferably 125 mg/cm3 to 325 mg/cm3, more preferably 150 mg/cm3 to 300 mg/cm3, more preferably 150 mg/cm3 to 290 mg/cm3, even more preferably 200 mg/cm3 to 280 mg/cm3.

The term "density" as used herein with respect to an aerosol-generating substrate refers to the bulk density of the aerosol-generating substrate. This can be calculated by measuring the total weight of the aerosol-generating substrate and dividing it by the volume of the strip of aerosol-generating substrate (excluding any wrapper).

The bulk density of the tobacco material in the aerosol generating substrate can be calculated by dividing the sum of the mass of the tobacco material in the strip of the aerosol generating substrate by the volume of the aerosol generating substrate (excluding any wrapper). The mass of the tobacco material in the aerosol generating substrate can be determined by removing the tobacco material from the aerosol generating substrate and weighing the tobacco material. After adjusting the aerosol generating substrate according to ISO standard 3402:1999, the bulk density of the tobacco material in the aerosol generating substrate can be determined.

The aerosol generating substrate may include shredded tobacco material. The strip of aerosol generating substrate may include shredded tobacco material. The shredded tobacco material may be in the form of cut filler or tobacco cut filler. The density of such aerosol generating substrate or shredded tobacco material may be according to the following.

In certain preferred embodiments, the rod of the aerosol generating substrate comprises shredded tobacco material (e.g., tobacco cut filler) having a density of less than 350 mg/cm3, preferably less than 345 mg/cm3, preferably less than 325 mg/cm3, more preferably less than 300 mg/cm3, more preferably less than 290 mg/cm3, more preferably less than 280 mg/cm3. Preferably, the rod of the aerosol generating substrate comprises shredded tobacco material having a bulk density of at least 100 mg/cm3. More preferably, the rod of the aerosol generating substrate comprises shredded tobacco material having a bulk density of at least 125 mg/cm3. More preferably, the rod of the aerosol generating substrate comprises shredded tobacco material having a bulk density of at least 150 mg/cm3. Even more preferably, the rod of the aerosol generating substrate comprises shredded tobacco material having a bulk density of at least 200 mg/cm3. For example, the rod of the aerosol generating substrate may comprise shredded tobacco material having a density of 100 mg/cm3 to 350 mg/cm3, preferably 100 mg/cm3 to 345 mg/cm3, preferably 125 mg/cm3 to 325 mg/cm3, more preferably 150 mg/cm3 to 300 mg/cm3, more preferably 150 mg/cm3 to 290 mg/cm3, even more preferably 200 mg/cm3 to 280 mg/cm3.

Preferably, the RTD of the strip of aerosol-generating substrate is less than about 10 mm H ₂ O. More preferably, the RTD of the strip of aerosol-generating substrate is less than 9 mm H ₂ O. Even more preferably, the RTD of the strip of aerosol-generating substrate is less than 8 mm H ₂ O.

The RTD of the strip of aerosol-generating substrate is preferably at least 4 mm H ₂ O. More preferably, the RTD of the strip of aerosol-generating substrate is at least 5 mm H ₂ O. Even more preferably, the RTD of the strip of aerosol-generating substrate is at least 6 mm H ₂ O.

In some embodiments, the strip of aerosol-generating substrate has an RTD of 4 mm H ₂ O to 10 mm H ₂ O, preferably 5 mm H ₂ O to 10 mm H ₂ O, preferably 6 mm H ₂ O to 25 mm H ₂ O. In other embodiments, the strip of aerosol-generating substrate has an RTD of 4 mm H ₂ O to 20 mm H ₂ O, preferably 5 mm H ₂ O to 18 mm H ₂ O, preferably 6 mm H ₂ O to 16 mm H ₂ O. In further embodiments, the strip of aerosol-generating substrate has an RTD of 4 mm H ₂ O to 15 mm H ₂ O, preferably 5 mm H ₂ O to 14 mm H ₂ O, more preferably 6 mm H ₂ O to 12 mm H ₂ O.

Unless otherwise stated, the resistance to draw (RTD) of a component or aerosol generating article is measured in accordance with ISO 6565-2015. RTD refers to the pressure required to force air through the full length of a component. The term "pressure drop" or "draw resistance" 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 generally made in tests at a temperature of 22 degrees Celsius, a pressure of 101 kPa (about 760 Torr) and a relative humidity of 60%, at a volume flow rate of 17.5 ml/sec at the output or downstream end of the measuring component. Conditions for smoking and smoking machine specifications are set forth in ISO Standard 3308 (ISO 3308:2000). The atmosphere for conditioning and testing is set forth in ISO Standard 3402 (ISO 3402:1999).

The aerosol-generating substrate may be a solid aerosol-generating substrate. Preferably, the aerosol-generating substrate comprises an aerosol-forming agent. The aerosol-forming agent may be any suitable known compound or mixture of compounds that facilitates the formation of a dense and stable aerosol in use. The aerosol-forming agent may facilitate that the aerosol is substantially resistant to thermal degradation at the temperatures typically applied during the use of the aerosol-generating article. Suitable aerosol-forming agents are, for example: polyols, such as triethylene glycol, 1,3-butylene glycol, propylene glycol and glycerol; esters of polyols, such as mono-, di- or triacetates of glycerol; aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate; and combinations thereof.

Preferably, the aerosol former comprises one or more of glycerol and propylene glycol. The aerosol former may consist of glycerol or propylene glycol or a combination of glycerol and propylene glycol.

Preferably, the aerosol-generating substrate comprises at least 5 wt% aerosol-forming agent based on the dry weight of the aerosol-generating substrate, more preferably at least 6 wt% aerosol-forming agent based on the dry weight of the aerosol-generating substrate, and at least 8 wt% aerosol-forming agent based on the dry weight of the aerosol-generating substrate.

Preferably, the aerosol-generating substrate comprises less than 90 wt % aerosol-forming agent based on the dry weight of the aerosol-generating substrate, more preferably less than 80 wt % aerosol-forming agent based on the dry weight of the aerosol-generating substrate, more preferably less than 70 wt % aerosol-forming agent based on the dry weight of the aerosol-generating substrate, more preferably less than 60 wt % aerosol-forming agent based on the dry weight of the aerosol-generating substrate, more preferably less than 50 wt % aerosol-forming agent based on the dry weight of the aerosol-generating substrate, more preferably less than 40 wt % aerosol-forming agent based on the dry weight of the aerosol-generating substrate.

More preferably, the aerosol-generating substrate contains less than 30 wt% aerosol-forming agent based on the dry weight of the aerosol-generating substrate, more preferably less than 25 wt% aerosol-forming agent based on the dry weight of the aerosol-generating substrate, and more preferably less than 20 wt% aerosol-forming agent based on the dry weight of the aerosol-generating substrate.

For example, the aerosol-generating substrate may contain between 5 wt % and 30 wt % aerosol-forming agent based on the dry weight of the aerosol-generating substrate, more preferably between 6 wt % and 25 wt % aerosol-forming agent based on the dry weight of the aerosol-generating substrate, and more preferably between 10 wt % and 20 wt % aerosol-forming agent based on the dry weight of the aerosol-generating substrate.

For example, preferably, the aerosol generating substrate can comprise the glycerine between 5 % by weight and 30 % by weight based on the dry weight of the aerosol generating substrate, more preferably the glycerine between 6 % by weight and 25 % by weight based on the dry weight of the aerosol generating substrate, more preferably the glycerine between 10 % by weight and 20 % by weight based on the dry weight of the aerosol generating substrate. In some preferred embodiments of the present invention, the aerosol generating substrate comprises the tobacco material of shredding. For example, as described in more detail below, the tobacco material of shredding can be the form of shredded filler. Alternatively, the tobacco material of shredding can be the form of shredded material of homogenized tobacco material. Suitable homogenized tobacco material for the present invention is described below.

In the context of this specification, the term "cut filler" is used to describe a blend of chopped plant material, such as tobacco plant material, particularly including one or more of leaves, processed stems and ribs, homogenised plant material.

Cut filler may also include other post-cut filler tobaccos or addenda.

Preferably, the shredded filler comprises at least 25% plant leaves, more preferably at least 50% plant leaves, still more preferably at least 75% plant leaves, and most preferably at least 90% plant leaves. Preferably, the plant material is one of tobacco, mint, tea and cloves. Most preferably, the plant material is tobacco. However, as will be discussed in more detail below, the present invention is equally applicable to other plant materials that are capable of releasing a substance that can subsequently form an aerosol when heat is applied.

Preferably, the cut filler comprises a tobacco plant material, which comprises a thin layer of one or more of flue-cured tobacco, sun-cured tobacco, spice tobacco and filler tobacco. With reference to the present invention, the term "tobacco" describes any plant member of the genus Nicotiana . Flue-cured tobacco is tobacco with generally large light-colored leaves. Throughout the specification, the term "flue-cured tobacco" is used for flue-cured tobacco. Examples of flue-cured tobacco are Chinese flue-cured tobacco, Brazilian flue-cured tobacco, American flue-cured tobacco, such as Virginia tobacco, Indian flue-cured tobacco, Tanzanian flue-cured tobacco or other African flue-cured tobacco. Flue-cured tobacco is characterized by a high sugar-nitrogen ratio. From a sensory perspective, flue-cured tobacco is a type of tobacco that is accompanied by a spicy and refreshing feeling after curing. Within the scope of the present invention, flue-cured tobacco is a tobacco having a reducing sugar content of between about 2.5% and about 20% by leaf dry weight and a total ammonia content of less than about 0.12% by leaf dry weight. Reducing sugars include, for example, glucose or fructose. Total ammonia includes, for example, ammonia and ammonia salts.

Sun-cured tobacco is tobacco with dark leaves that are usually large. Throughout the specification, the term "sun-cured tobacco" is used for tobacco that has been air-cured. In addition, sun-cured tobacco can be fermented. Tobacco that is mainly used for chewing, snuff, cigars and pipe blends is also included in this category. Usually, these sun-cured tobaccos are air-cured and can be fermented. From a sensory perspective, sun-cured tobacco is a type of tobacco that is accompanied by a dark cigar-type feeling of smoky flavor after curing. Sun-cured tobacco is characterized by a low sugar-nitrogen ratio. Examples of sun-cured tobacco are Malawi white burley or other African white burley, dark-cured Brazilian Galpao, sun-cured or air-cured Indonesian Kasturi. According to the present invention, sun-cured tobacco is a tobacco with a reducing sugar content of less than about 5% by tobacco leaf dry weight and a total ammonia content of up to about 0.5% by tobacco leaf dry weight.

Spicy tobacco is tobacco that often has small light-colored leaves. Throughout the specification, the term "spice tobacco" is used for other tobaccos with high aromatic compound (e.g., essential oil) content. From a sensory perspective, spice tobacco is a tobacco type that is accompanied by a spicy and aromatic sensation after baking. Examples of spice tobacco are Greek Oriental, Oriental Turkey, semi-Oriental tobacco, and baked American white burley, such as Perique, Rustica, American white burley, or Meriland. Filler tobacco is not a specific tobacco type, but it comprises a tobacco type that is mainly used to supplement other tobacco types used in the blend and does not bring a specific characteristic aroma into the final product. Examples of filler tobacco are stems, midribs, or stems of other tobacco types. A specific example can be a stem that is dried by baking the lower stem of Brazilian flue-cured tobacco.

The shredded filler suitable for use with the present invention can be similar to the shredded filler for conventional smoking articles in general. The shredded width of the shredded filler is preferably between 0.3 mm and 2.0 mm, more preferably the shredded width of the shredded filler is between 0.5 mm and 1.2 mm, and most preferably the shredded width of the shredded filler is between 0.6 mm and 0.9 mm. The shredded width can work in the thermal distribution of the strip inside of the aerosol generating substrate. Equally, the shredded width can work in the suction resistance of the product. In addition, the shredded width can affect the total density of the aerosol generating substrate as a whole.

The strand length of the shredded filler is a random value to some extent, because the length of the strand will depend on the overall size of the object from which the strand is cut. However, by adjusting the material before cutting, for example, by controlling the moisture content and overall fineness of the material, longer strands can be cut. Preferably, before arranging the strands to form the strips of the aerosol generating substrate, the strands have a length between about 10 millimeters and about 40 millimeters. Obviously, if the strands are arranged in the strips of the aerosol generating substrate with longitudinal extension, wherein the longitudinal extension of the section is lower than 40 millimeters, the strips of the final aerosol generating substrate may include strands that are shorter than the initial strand length on average. Preferably, the strand length of the shredded filler makes the strands between about 20% and 60% extend along the full length of the strips of the aerosol generating substrate. This prevents the strands from being easily removed from the strips of the aerosol generating substrate.

In a preferred embodiment, the weight of the shredded filler is between 80 milligrams and 400 milligrams, preferably between 150 milligrams and 250 milligrams, more preferably between 170 milligrams and 220 milligrams. The shredded filler of this amount usually allows enough materials to form an aerosol. In addition, in view of the above-mentioned constraints to diameter and size, when the aerosol generating substrate comprises plant material, this allows the balance density between the fluid paths in the strip of the aerosol generating substrate in energy absorption, suction resistance and the strip of the aerosol generating substrate.

Preferably, the shredded filler is soaked with an aerosol former. Soaking the shredded filler can be accomplished by spraying or by other suitable application methods. The aerosol former can be applied to the blend during the preparation of the shredded filler. For example, the aerosol former can be applied to the blend in a direct conditioning casing cylinder (DCCC). The aerosol former can be applied to the shredded filler using a conventional machine. The aerosol former can be any suitable known compound or mixture of compounds that helps to form a dense and stable aerosol in use. The aerosol former can facilitate the aerosol to be substantially resistant to thermal degradation at temperatures typically applied during the use of the aerosol-generating article. Suitable aerosol formers are, for example: polyols, such as triethylene glycol, 1,3-butylene glycol, propylene glycol and glycerol; esters of polyols, such as mono-, di- or triacetates of glycerol; aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate; and combinations thereof.

Preferably, the aerosol former comprises one or more of glycerol and propylene glycol. The aerosol former may consist of glycerol or propylene glycol or a combination of glycerol and propylene glycol.

Preferably, the amount of aerosol forming agent is at least 5% by weight based on dry weight, preferably between 5% and 30% by weight based on dry weight of the cut filler, more preferably, the amount of aerosol forming agent is between 6% and 20% by weight based on dry weight of the cut filler, for example, the amount of aerosol forming agent is between 8% and 15% by weight based on dry weight of the cut filler. When the aerosol forming agent is added to the cut filler in the above amounts, the cut filler may become relatively sticky. This advantageously helps to keep the cut filler at a predetermined position within the article, because the particles of the cut filler show a tendency to adhere to surrounding cut filler particles and surrounding surfaces (e.g., the inner surface of the packaging defining the cut filler).

For some embodiments, the amount of aerosol former has a target value of about 13% by weight based on the dry weight of the cut filler. Whether the cut filler includes plant leaves or homogenized plant material, the most effective amount of aerosol former will also depend on the cut filler. For example, among other factors, the type of cut filler will determine to what extent the aerosol former can facilitate the release of the substance from the cut filler.

For these reasons, as described above, a rod of aerosol-generating substrate comprising a cut filler is able to effectively generate a sufficient amount of aerosol at relatively low temperatures. A temperature of between 150 degrees Celsius and 200 degrees Celsius in a heating chamber may be sufficient to generate a sufficient amount of aerosol for one such cut filler, while in an aerosol-generating device using a tobacco cast leaf, a temperature of about 250 degrees Celsius is typically employed.

Another advantage associated with operating at lower temperatures is the reduced need to cool the aerosol. Since low temperatures are typically used, a simpler cooling function is sufficient. This in turn allows the use of a simpler and less complex structure of the aerosol generating article.

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

As used herein, the term "homogenized plant material" includes any plant material formed by the agglomeration of plant particles. For example, sheets or webs of homogenized tobacco material used for aerosol-generating substrates of the present invention can be formed by agglomerating particles of tobacco material, which are obtained by pulverizing, grinding or grinding plant material and one or more of optional tobacco leaves and tobacco stems. Homogenized plant material can be produced by casting, extruding, papermaking technology or other any suitable process known in the art.

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

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

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

Homogenized plant material can be in the form of multiple stocks, strips or fragments. As used herein, the term "stock" describes an elongated element material whose length is significantly greater than its width and thickness. The term "stock" should be considered to include strips, fragments and any other homogenized plant material with similar forms. The stock of homogenized plant material can be formed by the sheet of homogenized plant material, such as by cutting or chopping, or by other methods, such as by extrusion methods.

In certain embodiments, due to the splitting or splitting of the homogenized plant material sheet during the formation of the aerosol generating substrate, for example, due to curling, the stock can be formed in situ in the aerosol generating substrate. The homogenized plant material stocks in the aerosol generating substrate can be separated from each other. Alternatively, each stock of the homogenized plant material in the aerosol generating substrate can be connected to adjacent one or more stocks at least in part along the length of the stock. For example, adjacent stocks can be connected by one or more fibers. This can occur, for example, due to the splitting of the sheet of the homogenized plant material during the production of the aerosol generating substrate and the formation of stocks, as described above.

As mentioned above, when the homogenised plant material is in the form of one or more sheets, the sheets may be produced by a casting process. Alternatively, the sheets of homogenised plant material may be produced by a papermaking process.

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

One or more sheets as described herein may each individually have a grammage between 100 g/m2 and 600 g/m2.

One or more sheets as described herein may each individually have a density of 0.3 g/cm3 to 1.3 g/cm3, and preferably 0.7 g/cm3 to 1.0 g/cm3.

In embodiments of the invention where the aerosol generating substrate comprises one or more sheets of homogenized plant material, the sheets are preferably in the form of one or more aggregated sheets. As used herein, the term "aggregated" means that the sheets of homogenized plant material are rolled, folded or otherwise compressed or contracted substantially transversely to the cylindrical axis of the rod or strip.

One or more sheets of homogenised plant material may be gathered transversely relative to their longitudinal axis and bounded by a wrapper to form a continuous strip or stick.

One or more sheets of homogenized plant material may advantageously be curled or similarly treated. As used herein, the term "curled" means that the sheet has a plurality of substantially parallel ridges or wrinkles. One or more sheets of homogenized plant material may be embossed, gravure, perforated or otherwise deformed to provide texture on one or both sides of the sheet.

Preferably, one or more sheets of homogenized plant material are curled so that they have a plurality of ridges or wrinkles substantially parallel to the cylindrical axis of the rod. This treatment advantageously promotes the gathering of the curled sheets of homogenized plant material to form a rod. Preferably, one or more sheets of homogenized plant material can be gathered. It should be appreciated that the curled sheets of homogenized plant material may alternatively or additionally have a plurality of substantially parallel ridges or wrinkles, which are arranged at an acute angle or an obtuse angle to the cylindrical axis of the rod. The sheet may be curled to a certain extent so that the integrity of the sheet is destroyed at a plurality of parallel ridges or wrinkles, causing material separation, and resulting in the formation of fragments, strands or strips of homogenized plant material.

One or more sheets of homogenized plant material can be cut into stocks as described above. In such embodiments, the aerosol generating matrix comprises a plurality of homogenized plant material stocks. Stock can be used to form a rod. Usually, the width of these stocks is about 5 millimeters, or about 4 millimeters, or about 3 millimeters, or about 2 millimeters or less. The length of stock can be greater than about 5 millimeters, between about 5 millimeters and about 15 millimeters, about 8 millimeters to about 12 millimeters, or about 12 millimeters. Preferably, stock has substantially the same length as each other.

The homogenized plant material may comprise up to 95% by weight of plant particles on a dry weight basis. Preferably, the homogenized plant material comprises up to 90% by weight of plant particles on a dry weight basis, more preferably up to 80% by weight of plant particles, more preferably up to 70% by weight of plant particles, more preferably up to 60% by weight of plant particles, more preferably up to 50% by weight of plant particles.

For example, the homogenized plant material may include between 2.5 wt% and 95 wt% plant particles, or between 5 wt% and 90 wt% plant particles, or between 10 wt% and 80 wt% plant particles, or between 15 wt% and 70 wt% plant particles, or between 20 wt% and 60 wt% plant particles, or between 30 wt% and 50 wt% 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. The sheet material of the homogenized tobacco material of this type of embodiment of the present invention can have at least about 40% by weight on a dry basis, more preferably at least about 50% by weight on a dry basis, more preferably at least about 70% by weight on a dry basis, and most preferably at least about 90% by weight tobacco content on a dry basis.

With reference to the present invention, the particle of any plant member of the Nicotiana genus is described in term " tobacco particles ".Term " tobacco particles " comprises ground or pulverized tobacco leaf blade, ground or pulverized tobacco leaf stem, tobacco dust, tobacco fines and other granular tobacco byproducts formed in the processing, operation and transportation process of tobacco.In a preferred embodiment, tobacco particles are all derived from tobacco leaf blade basically.By contrast, isolated nicotine and nicotine salt are compounds derived from tobacco, but are not considered to tobacco particles for purposes of the present invention, and are not included in the percentage of granular plant material.

The homogenized plant material may also contain one or more aerosol formers. Upon volatilization, the aerosol formers may convey in the aerosol other volatile compounds such as nicotine and flavorings that are released from the aerosol-generating substrate upon heating. Suitable aerosol formers for inclusion in the homogenized plant material are known in the art and include, but are not limited to: polyols such as triethylene glycol, propylene glycol, 1,3-butylene glycol and glycerol; esters of polyols 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 former content of between 5 wt% and 30 wt% on a dry weight basis, for example between 10 wt% and 25 wt% on a dry weight basis or between 15 wt% and 20 wt% on a dry weight basis. The aerosol former may act as a wetting agent in the homogenized plant material.

In certain embodiments of the invention, the aerosol-generating article further comprises a susceptor element within the strip of aerosol-generating substrate.For example, the elongate susceptor element may be disposed substantially longitudinally within the strip of aerosol-generating substrate and in thermal contact with the aerosol-generating substrate.

As used herein with reference to the present invention, the term "susceptor element" refers to a material that is capable of converting electromagnetic energy into heat. When located within a fluctuating electromagnetic field, eddy currents induced in the susceptor element result in heating of the susceptor element. As the susceptor element is positioned in thermal contact with the aerosol-generating substrate, the aerosol-generating substrate is heated by the susceptor element.

The term "elongated" when used to describe a susceptor element means that the length dimension of the susceptor element is greater than its width dimension or its thickness dimension, such as greater than twice its width dimension or its thickness dimension.

The susceptor element is arranged substantially longitudinally within the strip. This means that the length dimension of the elongated susceptor element is arranged substantially parallel to the longitudinal direction of the strip, for example within plus or minus 10 degrees of parallel to the longitudinal direction of the strip. In a preferred embodiment, the elongated susceptor element may be positioned in a radially central position within the strip and extend along the longitudinal axis of the strip.

Preferably, the susceptor element extends all the way to the downstream end of the strip of aerosol generating substrate. In some embodiments, the susceptor element may extend all the way to the upstream end of the strip of aerosol generating substrate. In particularly preferred embodiments, the susceptor element has substantially the same length as the strip of aerosol generating substrate and extends from the upstream end of the strip to the downstream end of the strip.

The susceptor element is preferably in the form of a pin, a bar, a strip or a blade.

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

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

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

The thickness of the susceptor element is typically 0.01 mm to 2 mm, such as 0.5 mm to 2 mm. In some embodiments, the susceptor element preferably has a thickness of 10 microns to 500 microns, more preferably 10 microns to 100 microns.

If the susceptor element has a constant cross-section, for example a circular cross-section, it has a preferred width or diameter of 1 mm to 5 mm.

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

If the susceptor element has the form of a strip or blade, the strip or blade preferably has a rectangular shape and a thickness of 0.03 mm to 0.15 mm, more preferably 0.05 mm to 0.09 mm. For example, the susceptor element in the form of a strip or blade may have a thickness of 0.07 mm.

In a preferred embodiment, the elongated susceptor elements are in the form of strips or blades, preferably having a rectangular shape, and having a thickness of 55 to 65 microns.

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

Preferably, the elongate susceptor element has a length that is the same as or shorter than the length of the aerosol-generating substrate.Preferably, the elongate susceptor element has the same length as the aerosol-generating substrate.

The susceptor element may be formed from any material that is capable of being inductively heated to a temperature sufficient to generate an aerosol from the aerosol-generating substrate.Preferably the susceptor element comprises metal or carbon.

Preferred susceptor elements may include or consist of ferromagnetic materials, such as ferromagnetic alloys, ferritic iron, or ferromagnetic steel or stainless steel. Suitable susceptor elements may be or include aluminum. Preferred susceptor elements may be formed of 400 series stainless steel, such as 410 grade or 420 grade or 430 grade stainless steel. Different materials will dissipate different amounts of energy when positioned within an electromagnetic field having similar frequency and field strength values.

Thus, parameters of the susceptor element such as material type, length, width and thickness may all be altered to achieve the desired power dissipation within a known electromagnetic field.Preferred susceptor elements may be heated to temperatures in excess of 250 degrees Celsius.

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

The susceptor element is arranged in thermal contact with the aerosol-generating substrate. Thus, when the susceptor element heats up, the aerosol-generating substrate heats up and forms an aerosol. Preferably, the susceptor element is arranged in direct physical contact with the aerosol-generating substrate, for example within the aerosol-generating substrate.

As described above, the strip of aerosol generating substrate may be defined by a wrapper. The wrapper defining the strip of aerosol generating substrate may be a paper wrapper or a non-paper wrapper. Suitable paper wrappers for use in particular embodiments of the invention are known in the art and include, but are not limited to: cigarette papers; and filter segment wrappers. Suitable non-paper wrappers for use in particular embodiments of the invention are known in the art and include, but are not limited to, sheets of homogenized tobacco material.

The paper wrapper may have a grammage of at least 15gsm (grams per square meter), preferably at least 20gsm. The paper wrapper may have a grammage of less than or equal to 35gsm, preferably less than or equal to 30gsm. The paper wrapper may have a grammage of 15gsm to 35gsm, preferably 20gsm to 30gsm. In a preferred embodiment, the paper wrapper may have a grammage of 25gsm. The paper wrapper may have a thickness of at least 25 microns, preferably at least 30 microns, more preferably at least 35 microns. The paper wrapper may have a thickness of less than or equal to 55 microns, preferably less than or equal to 50 microns, more preferably less than or equal to 45 microns. The paper wrapper may have a thickness of 25 microns to 55 microns, preferably 30 microns to 50 microns, more preferably 35 microns to 45 microns. 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 laminate comprising a plurality of layers. Preferably, the wrapper is formed from an aluminium co-laminated sheet. In the event that the aerosol generating substrate should ignite rather than heat up in the intended manner, the use of a co-laminated sheet comprising aluminium advantageously prevents combustion of the aerosol generating substrate.

The paper layer of the co-laminated sheet may have a grammage of at least 35 gsm, preferably at least 40 gsm. The paper layer of the co-laminated sheet may have a grammage of less than or equal to 55 gsm, preferably less than or equal to 50 gsm. The paper layer of the co-laminated sheet may have a grammage of 35 gsm to 55 gsm, preferably 40 gsm to 50 gsm. In a preferred embodiment, the paper layer of the co-laminated sheet may have a grammage of 45 gsm.

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

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

The metal layer of the co-laminated sheet may have a grammage of at least 12 gsm, preferably at least 15 gsm. The metal layer of the co-laminated sheet may have a grammage of less than or equal to 25 gsm, preferably less than or equal to 20 gsm. The metal layer of the co-laminated sheet may have a grammage of 12 gsm to 25 gsm, preferably 15 gsm to 20 gsm. In a preferred embodiment, the metal layer of the co-laminated sheet may have a grammage of 17 gsm.

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

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

The wrapper of the strip defining the aerosol generating substrate may be a paper wrapper comprising PVOH (polyvinyl alcohol) or silicone (or polysiloxane) (or polysiloxane). The addition of PVOH (polyvinyl alcohol) or silicone (or polysiloxane) may improve the grease barrier properties of the wrapper.

PVOH or silicone (or polysiloxane) may be applied as a surface coating to the paper layer, such as disposed on the outer surface of the wrapper paper layer of the strip defining the aerosol generating substrate. PVOH or silicone (or polysiloxane) may be disposed on the outer surface of the wrapper paper layer and form a layer thereon. PVOH or silicone (or polysiloxane) may be disposed on the inner surface of the wrapper paper layer. PVOH or silicone (or polysiloxane) may be disposed on the inner surface of the aerosol generating article paper layer and form a layer thereon. PVOH or silicone (or polysiloxane) may be disposed on the inner and outer surfaces of the wrapper paper layer. PVOH or silicone (or polysiloxane) may be disposed on the inner and outer surfaces of the wrapper paper layer and form a layer thereon.

The paper packaging material comprising PVOH or silicone (or polysiloxane) may have a grammage of at least 20gsm, preferably at least 25gsm, and more preferably at least 30gsm. The paper packaging material comprising PVOH or silicone (or polysiloxane) may have a grammage of less than or equal to 50gsm, preferably less than or equal to 45gsm, and more preferably less than or equal to 40gsm. The paper packaging material comprising PVOH or silicone (or polysiloxane) may have a grammage of 20gsm to 50gsm, preferably 25gsm to 45gsm, and more preferably 30gsm to 40gsm. In a particularly preferred embodiment, the paper packaging material comprising PVOH or silicone (or polysiloxane) may have a grammage of 35gsm.

The paper packaging material comprising PVOH or silicone (or polysiloxane) may have a thickness of at least 25 microns, preferably at least 30 microns, and more preferably at least 35 microns. The paper packaging material comprising PVOH or silicone (or polysiloxane) may have a thickness of less than or equal to 50 microns, preferably less than or equal to 45 microns, and more preferably less than or equal to 40 microns. The paper packaging material comprising PVOH or silicone (or polysiloxane) may have a thickness of 25 to 50 microns, preferably 30 to 45 microns, and more preferably 35 to 40 microns. In a particularly preferred embodiment, the paper packaging material comprising PVOH or silicone (or polysiloxane) may have a thickness of 37 microns.

The wrapper of the strip defining the aerosol generating substrate may include a flame retardant composition comprising one or more flame retardant compounds. The term "flame retardant compound" is used herein to describe compounds that, when added to or otherwise incorporated into a carrier substrate (e.g., a paper or plastic compound), provide varying degrees of flammability protection to the carrier substrate. In practice, the flame retardant compound may be activated by the presence of an ignition source and is adapted to prevent or slow the further development of ignition by a variety of different physical and chemical mechanisms.

The flame retardant composition may also typically include one or more non-flame retardant compounds, i.e., one or more compounds (e.g., solvents, excipients, fillers) that do not actively contribute to providing flammability protection to the carrier substrate, but are used to facilitate the application of one or more flame retardant compounds to or in the packaging or both. Some non-flame retardant compounds of the flame retardant composition—e.g., solvents—are volatile and may evaporate from the packaging upon drying after the flame retardant composition is applied to or in the packaging base material or both. Thus, although such non-flame retardant compounds form part of the formulation of the flame retardant composition, in the packaging of the aerosol-generating article, they may no longer be present or they may only be detectable in trace amounts.

Many suitable flame retardant compounds are known to the skilled person. In particular, several flame retardant compounds and formulations suitable for treating cellulosic materials are known and have been disclosed and can be used in the manufacture of packaging for aerosol-generating articles according to the present invention.

For example, the flame retardant composition may include a polymer and a mixed salt based on at least one monocarboxylic acid, dicarboxylic acid and/or tricarboxylic acid, at least one polyphosphoric acid, pyrophosphoric acid and/or phosphoric acid, and a hydroxide or salt of an alkali metal or alkaline earth metal, wherein the at least one monocarboxylic acid, dicarboxylic acid and/or tricarboxylic acid forms a carboxylate with the hydroxide or salt, and the at least one polyphosphoric acid, pyrophosphoric acid and/or phosphoric acid forms a phosphate with the hydroxide or salt. Preferably, the flame retardant composition may also include a carbonate of an alkali metal or an alkaline earth metal. Alternatively, the flame retardant composition may include cellulose modified with at least one C ₁₀ or higher fatty acid, tall oil fatty acid (TOFA), phosphorylated linseed oil, phosphorylated downstream corn oil. Preferably, at least one C ₁₀ or higher fatty acid is selected from capric acid, myristic acid, palmitic acid, and combinations thereof.

In a package comprising a flame retardant composition suitable for an aerosol generating article according to the present invention, the flame retardant composition may be arranged in a treatment portion of the package. This means that the flame retardant composition has been applied to or in a corresponding portion of the packaging base material of the package, or both on and in the corresponding portion. Therefore, in the treatment portion, the package has an overall dry basis weight greater than the dry basis weight of the packaging base material. The treatment portion of the package may extend over at least 10% of the outer surface area of the strip of the aerosol generating substrate defined by the package, preferably over at least 20% of the outer surface area of the strip of the aerosol generating substrate defined by the package, more preferably over at least 40% of the outer surface area of the strip of the aerosol generating substrate, and even more preferably over at least 60% of the outer surface area of the strip of the aerosol generating substrate. Most preferably, the treatment portion of the package extends over at least 80% of the outer surface area of the strip of the aerosol generating substrate. In a particularly preferred embodiment, the treatment portion of the package extends over at least 90% or even 95% of the outer surface area of the strip of the aerosol generating substrate. Most preferably, the treatment portion of the wrapper extends over substantially the entire outer surface area of the strip of aerosol-generating substrate.

The packaging material including the flame retardant composition may have a grammage of at least 20 gsm, preferably at least 25 gsm, and more preferably at least 30 gsm. The packaging material including the flame retardant composition may have a grammage of less than or equal to 45 gsm, preferably less than or equal to 40 gsm, and more preferably less than or equal to 35 gsm. The packaging material including the flame retardant composition may have a grammage of 20 gsm to 45 gsm, preferably 25 gsm to 40 gsm, and more preferably 30 gsm to 35 gsm. In some preferred embodiments, the packaging material including the flame retardant composition may have a grammage of 33 gsm.

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

Aerosol generating articles according to the present disclosure may also include an upstream section located upstream of the strip of aerosol generating substrate. The upstream section is preferably positioned immediately upstream of the strip of aerosol generating substrate. The upstream section preferably extends between the upstream end of the aerosol generating article and the strip of aerosol generating substrate. The upstream section may include one or more upstream elements located upstream of the strip of aerosol generating substrate. Such one or more upstream elements are described within the present disclosure.

The aerosol generating article of the present invention preferably includes an upstream element located upstream and near the aerosol generating substrate. The upstream element advantageously prevents direct physical contact with the upstream end of the aerosol generating substrate. For example, where the aerosol generating substrate includes a receptor element, the upstream element may prevent direct physical contact with the upstream end of the receptor element. This helps prevent the receptor element from shifting or deforming during handling or transporting the aerosol generating article. This in turn helps fix the form and position of the receptor element. In addition, the presence of the upstream element helps prevent any loss of the substrate, which may be advantageous, for example, if the substrate contains particulate plant material.

Where the aerosol-generating substrate comprises shredded tobacco (such as tobacco cut filler), the upstream section or elements thereof may additionally help prevent loose tobacco particles from being lost from the upstream end of the article. This may be particularly important, for example, when the shredded tobacco has a relatively low density.

The upstream section or an upstream element thereof may additionally provide a degree of protection for the aerosol-generating substrate during storage, as it covers, at least to some extent, the upstream end of the aerosol-generating substrate which might otherwise be exposed.

For aerosol-generating articles intended to be inserted into a cavity in an aerosol-generating device such that the aerosol-generating substrate can be heated externally within the cavity, the upstream section or its upstream element may advantageously facilitate the insertion of the upstream end of the article into the cavity. The inclusion of the upstream element may additionally protect the end of the strip of the aerosol-generating substrate during insertion of the article into the cavity, minimizing the risk of damage to the substrate.

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

The upstream element may be a porous rod element. Preferably, the upstream element has a porosity of at least 50% in the longitudinal direction of the aerosol generating article. More preferably, the upstream element has a porosity of between 50% and 90% in the longitudinal direction. The porosity of the upstream element in the longitudinal direction is defined by the ratio of the cross-sectional area of the material forming the upstream element to the internal cross-sectional area of the aerosol generating article at the location of the upstream element.

The upstream element may be made of a porous material or may include a plurality of openings. For example, this may be achieved by laser perforation. Preferably, the plurality of openings are evenly distributed over the cross section of the upstream element.

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

The upstream element may be formed from a material that is impermeable to air.In such embodiments, the aerosol-generating article may be configured such that air flows into the strip of aerosol-generating substrate via suitable ventilation means provided in the packaging.

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

The RTD of the upstream element is preferably less than 30 mm H ₂ O. More preferably, the RTD of the upstream element is less than 20 mm H ₂ O. Even more preferably, the RTD of the upstream element is less than or equal to 10 mm H ₂ O. Even more preferably, the RTD of the upstream element is less than or equal to 5 mm H ₂ O. Even more preferably, the RTD of the upstream element is less than or equal to 2 mm H ₂ O.

The RTD of the upstream element may be at least 0.1 mm _H2O , or at least 0.25 mm _H2O , or at least 0.5 mm _H2O .

In some embodiments, the RTD of the upstream element is 0.1 mmH ₂ O to 30 mmH ₂ O, preferably 0.25 mmH ₂ O to 30 mmH ₂ O, and preferably 0.5 mmH ₂ O to 30 mmH ₂ O. In other embodiments, the RTD of the upstream element is 0.1 mmH ₂ O to 20 mmH ₂ O, preferably 0.25 mmH ₂ O to 20 mmH ₂ O, and preferably 0.5 mmH ₂ O to 20 mmH ₂ O. In further embodiments, the RTD of the upstream element is 0.1 mmH ₂ O to 10 mmH ₂ O, preferably 0.25 mmH ₂ O to 10 mmH ₂ O, and more preferably 0.5 mmH ₂ O to 10 mmH ₂ O. In other embodiments, the upstream element has an RTD of 0.1 _mmH2O to 5 _mmH2O , preferably 0.25 _mmH2O to 5 _mmH2O , more preferably 0.5 _mmH2O to 5 _mmH2O . In other embodiments, the upstream element has an RTD of 0.1 _mmH2O to 2 _mmH2O , preferably 0.25 _mmH2O to 2 _mmH2O , more preferably 0.5 _mmH2O to ₂ mmH2O.

Preferably, the RTD of the upstream element is less than 2 mm _H2O /mm length, more preferably less than 1.5 mm _H2O /mm length, more preferably less than 1 mm _H2O /mm length, more preferably less than 0.5 mm _H2O /mm length, more preferably less than 0.3 mm _H2O /mm length, more preferably less than 0.2 mm _H2O /mm length.

Preferably, the combined RTD of the upstream section or upstream element thereof and the strip of aerosol-generating substrate is less than 15 mm _H2O , more preferably less than 12 mm _H2O , more preferably less than 10 mm _H2O .

In certain preferred embodiments, the upstream element is formed by a solid cylindrical rod element having a filled cross section. Such rod elements may be referred to as "plain" elements. As described above, solid rod elements may be porous, but do not have a tubular form and therefore do not provide longitudinal flow channels. Solid rod elements preferably have a substantially uniform cross section.

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

Preferably, the diameter of the longitudinal lumen of the hollow tubular segment forming the upstream element is at least 3 mm, more preferably at least 3.5 mm, more preferably at least 4 mm, and more preferably at least 4.5 mm. Preferably, the diameter of the longitudinal lumen is maximized in order to minimize the RTD of the upstream segment or its upstream element.

Preferably, the wall thickness of the hollow tubular segment is less than 2 mm, more preferably less than 1.5 mm, and more preferably less than 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, for example, be made of the same material as one of the other components of the aerosol generating article, such as a downstream filter segment or a hollow tubular cooling element. Suitable materials for forming the upstream element include filter materials, ceramics, polymeric materials, cellulose acetate, paperboard, zeolites, or an aerosol generating matrix. The upstream element may include a rod of cellulose acetate. The upstream element may include a hollow acetate tube or a paperboard tube.

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

Preferably, the upstream section or its upstream element has an outer diameter substantially equal to the outer diameter of the aerosol generating article. Preferably, the outer diameter of the upstream section or its upstream element is between 5 mm and 8 mm, more preferably between 5.25 mm and 7.5 mm, more preferably between 5.5 mm and 7 mm.

Preferably, the upstream section or upstream element has a length of at least 2 mm, more preferably at least 3 mm, more preferably at least 4 mm.

Preferably, the upstream section or upstream element has a length of between 2 mm and 10 mm, more preferably between 3 mm and 8 mm, more preferably between 2 mm and 6 mm, more preferably between 3 mm and 6 mm, more preferably between 4 mm and 8 mm, more preferably between 4 mm and 6 mm. In a particularly preferred embodiment, the upstream section or upstream element has a length of 5 mm. The length of the upstream section or upstream element may advantageously be varied in order to provide a desired overall length of the aerosol-generating article. For example, in case 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 upstream element may be increased in order to maintain the same overall length of the article.

Additionally, for articles intended for external heating, the length of the upstream section or its upstream element may be used to control the position of the aerosol-generating article within the cavity of the aerosol-generating device. This may advantageously ensure that the position of the aerosol-generating substrate within the cavity may be optimized for heating, and may also optimize the position of any ventilation.

The upstream section is preferably defined by a wrapper such as a stick wrapper. The wrapper defining the upstream section is preferably a rigid stick wrapper, for example a stick wrapper having a basis weight of at least 80 grams per square meter (gsm), or at least 100 gsm, or at least 110 gsm. This provides structural rigidity to the upstream section.

The upstream section is preferably connected to the strip of aerosol-generating substrate, and optionally at least a portion of the downstream section, by means of an overwrap as described herein.

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

The length of the downstream section may be at least 40 mm. The length of the downstream section may be at least 45 mm. The length of the downstream section may be greater than 45 mm. The length of the downstream section may be at least 48 mm. The length of the downstream section may be at least 50 mm.

The length of the downstream section may be less than 75 mm. The length of the downstream section may be equal to or less than 70 mm. The length of the downstream section may be equal to or less than 65 mm.

For example, the length of the downstream section may be between 40 mm and 75 mm, or between 45 mm and 75 mm, or between 48 mm and 75 mm, or between 50 mm and 75 mm. In other embodiments, the length of the downstream section may be between 40 mm and 70 mm, or between 45 mm and 70 mm, or between 48 mm and 70 mm, or between 50 mm and 70 mm. In other embodiments, the length of the downstream section may be between 40 mm and 65 mm, or between 45 mm and 65 mm, or between 48 mm and 65 mm, or between 50 mm and 65 mm.

Providing a relatively long downstream section ensures that when the aerosol-generating article is received in the aerosol-generating device, a suitable length of the article protrudes from the aerosol-generating device. Such a suitable protruding length facilitates easy insertion and extraction of the article from the device, which also ensures that the upstream part of the article (particularly during insertion) is properly inserted into the device with a reduced risk of damage.

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

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

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

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

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

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

Preferably, the ratio between the length of the downstream segment and the length of the strip of aerosol-generating substrate is at least 1.0. More preferably, the ratio between the length of the downstream segment and the length of the strip of aerosol-generating substrate is at least 1.25. More preferably, the ratio between the length of the downstream segment and the length of the strip of aerosol-generating substrate is at least 1.5. More preferably, the ratio between the length of the downstream segment and the length of the strip of aerosol-generating substrate is at least 1.75.

The ratio between the length of the downstream segment and the length of the strip of aerosol-generating substrate is preferably less than 3.5. Preferably, the ratio between the length of the downstream segment and the length of the strip of aerosol-generating substrate is less than 3.25. More preferably, the ratio between the length of the downstream segment and the length of the strip of aerosol-generating substrate is less than 3.0. Even more preferably, the ratio between the length of the downstream segment and the length of the strip of aerosol-generating substrate is less than 2.75.

In some embodiments, the ratio between the length of the downstream segment and the length of the strip of the aerosol-generating substrate is 1.0 to 3.5, preferably 1.25 to 3.5, more preferably 1.50 to 3.5, and even more preferably 1.75 to 3.5. In other embodiments, the ratio between the length of the downstream segment and the length of the strip of the aerosol-generating substrate is 1.0 to 3.25, preferably 1.25 to 3.25, more preferably 1.50 to 3.25, and even more preferably 1.75 to 3.25. In further embodiments, the ratio between the length of the downstream segment and the length of the strip of the aerosol-generating substrate is 1.0 to 3.0, preferably 1.25 to 3.0, more preferably 1.50 to 3.0, and even more preferably 1.75 to 3.0. In further embodiments, the ratio between the length of the downstream section and the length of the strip of aerosol-generating substrate is from 1.0 to 2.75, preferably from 1.25 to 2.75, more preferably from 1.50 to 2.75, even more preferably from 1.75 to 2.75.

Preferably, the downstream section of an aerosol-generating article according to the invention comprises a hollow tubular cooling element disposed downstream of the strip of aerosol-generating substrate.The hollow tubular cooling element may advantageously provide an aerosol-cooling element for the aerosol-generating article.

The hollow tubular cooling element is arranged immediately downstream of the strip of aerosol generating substrate. In other words, the hollow tubular cooling element may abut the downstream end of the strip of aerosol generating substrate. The hollow tubular cooling element may define the upstream end of the downstream section of the aerosol generating article. The downstream end of the aerosol generating article may coincide with the downstream end of the downstream section. In some embodiments, the downstream section of the aerosol generating article comprises a single hollow tubular element. In other words, the downstream section of the aerosol generating article may comprise only one hollow tubular element. In other embodiments, as described below, the downstream section comprises two or more hollow tubular elements.

As used throughout this disclosure, the term "hollow tubular element" refers to a generally elongated element that defines a lumen or airflow passage along its longitudinal axis. In particular, the term "tubular" will hereinafter be used to refer to a tubular element having a substantially cylindrical cross-section and defining at least one airflow conduit that establishes uninterrupted 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 of the tubular element (e.g., alternative cross-sectional shapes) may be possible. The hollow tubular cooling element may be a single discrete element of the aerosol-generating article having a defined length and thickness.

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

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

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

In the context of the present invention, the hollow tubular cooling element provides an unrestricted flow channel. This means that the hollow tubular cooling element provides a negligible resistance to draw (RTD) level. The term "negligible RTD level" is used to describe a hollow tubular cooling element having an RTD of less than 1 mm _H2O /10 mm length, preferably less than 0.4 mm _H2O /10 mm length of the hollow tubular cooling element, and more preferably less than 0.1 mm _H2O /10 mm length of the hollow tubular cooling element.

The RTD of the hollow tubular cooling element is preferably less than or equal to 10 mm H ₂ O. More preferably, the RTD of the hollow tubular cooling element is less than or equal to 5 mm H ₂ O. Even more preferably, the RTD of the hollow tubular cooling element is less than or equal to 2.5 mm H ₂ O. Even more preferably, the RTD of the hollow tubular cooling element is less than or equal to 2 mm H ₂ O. Even more preferably, the RTD of the hollow tubular cooling element is less than or equal to 1 mm H ₂ O.

The RTD of the hollow tubular cooling element may be at least 0 mm _H2O , or at least 0.25 mm _H2O , or at least 0.5 mm _H2O , or at least 1 mm _H2O .

In some embodiments, the RTD of the hollow tubular cooling element is 0 mmH ₂ O to 10 mmH ₂ O, preferably 0.25 mmH ₂ O to 10 mmH ₂ O, preferably 0.5 mmH ₂ O to 10 mmH ₂ O. In other embodiments, the RTD of the hollow tubular cooling element is 0 mmH ₂ O to 5 mmH ₂ O, preferably 0.25 mmH ₂ O to 5 mmH ₂ O, preferably 0.5 mmH ₂ O to 5 mmH ₂ O. In other embodiments, the RTD of the hollow tubular cooling element is 1 mmH ₂ O to 5 mmH ₂ O. In further embodiments, the RTD of the hollow tubular cooling element is 0 mmH ₂ O to 2.5 mmH ₂ O, preferably 0.25 mmH ₂ O to 2.5 mmH ₂ O, more preferably 0.5 mmH ₂ O to 2.5 mmH ₂ O. In further embodiments, the RTD of the hollow tubular cooling element is 0 _mmH2O to 2 _mmH2O , preferably 0.25 _mmH2O to 2 _mmH2O , more preferably 0.5 _mmH2O to 2 _mmH2O . In particularly preferred embodiments, the RTD of the hollow tubular cooling element is 0 _mmH2O .

In an aerosol-generating article according to the invention, the overall RTD of the article depends substantially on the RTD of the strip and optionally on the RTD of downstream and/or upstream elements. This is because the hollow tubular cooling element is substantially empty and thus substantially only minimally affects the overall RTD of the aerosol-generating article.

Therefore, the flow channel should be free of any components that would hinder the flow of air in the longitudinal direction.Preferably, the flow channel is substantially empty, and particularly preferably the flow channel is empty.

As will be described in more detail within the present disclosure, the aerosol-generating article may include a ventilation zone at a location along the downstream segment. In some embodiments, the aerosol-generating article may include a ventilation zone at a location along the hollow tubular cooling element. This ventilation zone or any ventilation zone may extend through the peripheral wall of the hollow tubular cooling element. Thus, fluid communication is established between the flow channel defined by the interior of the hollow tubular cooling element and the external environment. Ventilation zones are further described within the present disclosure.

Preferably, the length of the hollow tubular cooling element is at least 20 mm. More preferably, the length of the hollow tubular cooling element is at least 30 mm. The length of the hollow tubular cooling element may be at least 40 mm. More preferably, the length of the hollow tubular cooling element is at least 45 mm.

The length of the hollow tubular cooling element is preferably less than 60 mm. More preferably, the length of the hollow tubular cooling element is less than 55 mm. More preferably, the length of the hollow tubular cooling element is less than 50 mm.

For example, the length of the hollow tubular cooling element can be between 20 mm and 60 mm, or between 30 mm and 60 mm, or between 40 mm and 60 mm, or between 45 mm and 60 mm. In other embodiments, the length of the hollow tubular cooling element can be between 20 mm and 55 mm, or between 30 mm and 55 mm, or between 40 mm and 55 mm, or between 45 mm and 55 mm. In other embodiments, the length of the hollow tubular cooling element can be between 20 mm and 50 mm, or between 30 mm and 50 mm, or between 40 mm and 50 mm, or between 45 mm and 50 mm.

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

Preferably, the ratio between the length of the hollow tubular cooling element and the length of the strip of aerosol-generating substrate is at least 1.0. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the strip of aerosol-generating substrate is at least 1.25. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the strip of aerosol-generating substrate is at least 1.5. More preferably, the ratio between the length of the hollow tubular cooling element and the length of the strip of aerosol-generating substrate is at least 1.75.

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

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

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

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

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

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

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

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

Providing a downstream segment or hollow tubular cooling element having the above ratio maximizes the aerosol cooling and formation benefits of having a relatively long hollow tubular cooling element while providing a sufficient amount of filtration for an aerosol generating article configured to heat but not burn. In addition, providing a longer hollow tubular cooling element can advantageously reduce the effective RTD of the downstream segment of the aerosol generating article, which is primarily defined by the RTD of the downstream filter segment.

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

The wall thickness of the hollow tubular cooling element may be less than or equal to 2 mm, preferably less than or equal to 1.5 mm, and even more preferably less than or equal to 1.25 mm. The wall thickness of the hollow tubular cooling element may be less than or equal to 1 mm. The wall thickness of the hollow tubular cooling element may be less than or equal to 500 microns.

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

Preferably, the wall thickness of the hollow tubular cooling element is 250 microns (0.25 mm).

At the same time, keeping the thickness of the peripheral wall of the hollow tubular cooling element relatively low ensures the total internal volume of the hollow tubular cooling element (which makes the aerosol available to start the nucleation process once the aerosol components leave the strips of the aerosol generating substrate), and effectively maximizes the cross-sectional surface area of the hollow tubular cooling element, while ensuring that the hollow tubular cooling element has the necessary structural strength to prevent the collapse of the aerosol generating article and provide some support for the strips of the aerosol generating substrate, and ensuring that the RTD of the hollow tubular cooling element is minimized. Larger values of the cross-sectional surface area of the cavity of the hollow tubular cooling element should be understood to be associated with a reduced velocity of the aerosol flow traveling along the aerosol generating article, which is also expected to be beneficial to aerosol nucleation. In addition, it seems that by utilizing a hollow tubular cooling element with a relatively low thickness, the ventilation air can be substantially prevented from diffusing before the ventilation air contacts and mixes with the aerosol flow, which is also understood to be further beneficial to the nucleation phenomenon. In practice, the effect of cooling on the formation of new aerosol particles can be enhanced by providing more controlled local cooling of the volatile substance flow.

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

The hollow tubular cooling element may have an outer diameter between 5 and 10 mm, such as between 5.5 and 9 mm or between 6 and 8 mm. In a preferred embodiment, the hollow tubular cooling element has an outer diameter of less than 7 mm.

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

The hollow tubular cooling element may have an inner diameter of at least 2 mm. For example, the hollow tubular cooling element may have an inner diameter of at least 3 mm, at least 4 mm, or at least 5 mm.

Providing a hollow tubular cooling element having an inner diameter as described above may advantageously provide the hollow tubular cooling element with sufficient rigidity and strength.

The hollow tubular cooling element may have an inner diameter of no more than 10 mm. For example, the hollow tubular cooling element may have an inner diameter of no more than 9 mm, no more than 8 mm, or no more than 7 mm.

Providing a hollow tubular cooling element having an inner diameter as described above may advantageously reduce the pumping resistance of the hollow tubular cooling element.

The hollow tubular cooling element may have an inner diameter of between 2 mm and 10 mm, between 3 mm and 9 mm, between 4 mm and 8 mm, or between 5 mm and 7 mm.

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

The ratio between the inner diameter of the hollow tubular cooling element and the outer diameter of the hollow tubular cooling element may not exceed 0.99. For example, the ratio between the inner diameter of the hollow tubular cooling element and the outer diameter of the hollow tubular cooling element may not exceed 0.98.

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

Providing a relatively large inner diameter may advantageously reduce the draw resistance of the hollow tubular cooling element and enhance cooling and nucleation of aerosol particles.

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

The hollow tubular cooling element may comprise a paper based material. The hollow tubular cooling element may comprise at least one paper layer. The paper may be a very stiff paper. The paper may be a curled paper, such as a curled heat resistant paper or a curled parchment paper.

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

The hollow tubular cooling element may be a paper tube. The hollow tubular cooling element may be a tube formed from spirally wound paper. The hollow tubular cooling element may be formed from a plurality of paper layers. The paper may have a basis weight of at least 50 g/m2, at least 60 g/m2, at least 70 g/m2 or at least 90 g/m2.

The hollow tubular cooling element may include a polymeric material. For example, the hollow tubular cooling element may include a polymer film. The polymer film may include a cellulose film. The hollow tubular cooling element may include low density polyethylene (HDPE) or polyhydroxyalkanoate (PHA) fibers. The hollow tube may include cellulose acetate tow.

Where the hollow tubular cooling element comprises cellulose acetate tow, the cellulose acetate tow may have a denier per filament between 2 and 4 and a total denier between 25 and 40.

In some embodiments, aerosol-generating articles according to the invention may comprise a ventilation zone at a position along the downstream segment. In more detail, in those embodiments in which the downstream segment comprises a hollow tubular cooling element, the ventilation zone may be provided at a position along the hollow tubular cooling element. Alternatively, in those embodiments in which the downstream segment comprises a downstream hollow tubular element, as described below, the ventilation zone may be provided at a position along the downstream hollow tubular element.

Thus, the ventilation cavity is provided downstream of the strip of aerosol-generating substrate.This provides several potential technical benefits.

Firstly, the inventors have found that one such ventilated hollow tubular cooling element provides particularly effective aerosol cooling. Thus, satisfactory aerosol cooling can be achieved even with a relatively short downstream section. This is particularly desirable because it enables the provision of an aerosol-generating article in which an aerosol-generating substrate (and in particular a tobacco-containing substrate) is heated without combustion, which combines satisfactory aerosol delivery with effective cooling of the aerosol to a temperature desired by the consumer.

Secondly, the inventors have surprisingly found that this rapid cooling of the volatile substances released upon heating the aerosol-generating substrate promotes enhanced nucleation of aerosol particles. As will be described in more detail below, this effect is particularly felt when the ventilation zone is arranged at a precisely defined position along the length of the hollow tubular cooling element relative to other components of the aerosol-generating article. In fact, the inventors have found that the beneficial effect of enhanced nucleation can significantly offset the potentially less desirable dilution effect caused by the introduction of ventilation air.

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

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

The distance between the ventilation zone and the upstream end of the upstream element may be less than or equal to 34 mm. Preferably, the distance between the ventilation zone and the upstream end of the upstream element is less than or equal to 33 mm. More preferably, the distance between the ventilation zone and the upstream end of the upstream element is less than or equal to 31 mm.

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

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

In a further embodiment, the distance between the ventilation zone and the upstream end of the upstream element is 25 mm to 31 mm, preferably 26 mm to 31 mm, more preferably 27 mm to 31 mm.

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

It has been discovered that an aerosol-generating article comprising a ventilation zone at a location along the hollow tubular cooling element at a distance from the upstream end of the upstream element within the above range has various benefits.

Firstly, it has been observed that such articles provide particularly satisfactory aerosol delivery to consumers, particularly where the aerosol-generating substrate comprises tobacco.

Without wishing to be bound by theory, the intense cooling caused by the ambient air drawn into the cavity of the hollow tubular cooling element at the ventilation zone is understood to accelerate the condensation of droplets of aerosol formers (e.g., glycerol) released from the aerosol-generating substrate upon heating. In turn, volatile nicotine and organic acids similarly released from the tobacco substrate accumulate on the newly formed aerosol former droplets and subsequently combine to form nicotine salts. Thus, the overall ratio of aerosol particle phase to aerosol gas phase can be increased compared to existing aerosol-generating articles.

Positioning the ventilation zone at a distance from the upstream end of the upstream element as described above advantageously reduces the flight time of the volatilized nicotine before the volatilized nicotine particles reach the droplets of the aerosol former. At the same time, such a positioning of the ventilation zone relative to the upstream end of the upstream element ensures that there is sufficient time and space for the accumulation of nicotine and the formation of nicotine salts to occur in significant proportions before the aerosol stream reaches the mouth of the consumer.

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

Aerosol-generating articles according to the invention may have a ventilation level of at least 2%.

Throughout this specification, the term "ventilation level" is used to denote the volume ratio between the airflow entering the aerosol-generating article via the ventilation zone (ventilation airflow) and the sum of the aerosol airflow and the ventilation airflow. The greater the ventilation level, the higher the dilution of the aerosol flow delivered to the consumer. The aerosol-generating article preferably has a ventilation level of at least 5%, more preferably at least 10%, even more preferably at least 12% or at least 15%.

Aerosol-generating articles according to the present invention may have a ventilation level of up to 90%. Preferably, aerosol-generating articles according to the present invention have a ventilation level of less than or equal to 80%, more preferably less than or equal to 70%, even more preferably less than or equal to 60%, most preferably less than or equal to 50%.

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

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

Without wishing to be bound by theory, the inventors have discovered that the temperature drop caused by cooler outside air entering the hollow tubular cooling element via the ventilation zone can have a beneficial effect on the nucleation and growth of aerosol particles.

The formation of aerosols from gas mixtures containing various chemical species depends on a delicate interplay of nucleation, evaporation and condensation as well as coalescence, taking into account changes in vapor concentration, temperature as well as velocity fields. The so-called classical nucleation theory is based on the assumption that a fraction of the molecules in the gas phase are large enough to remain coherent for a long time with sufficient probability (e.g., half the probability). These molecules represent some kind of critical, threshold molecular clusters in the transient molecular aggregate, which means that on average, smaller molecular clusters are likely to break up quickly into the gas phase, while larger clusters are likely to grow on average. Such critical clusters are considered to be the key nucleation cores from which droplets are expected to grow due to condensation of molecules in the vapor. The newly nucleated original droplet is assumed to appear with a certain original diameter and then may grow by several orders of magnitude. This process is facilitated and enhanced by condensation caused by rapid cooling of the surrounding vapor. In this regard, it should be remembered that evaporation and condensation are two aspects of the same mechanism, namely, gas-liquid mass transfer. While evaporation involves a net mass transfer from the droplet to the gas phase, condensation is a net mass transfer from the gas phase to the droplet phase. Evaporation (or condensation) will shrink (or grow) the droplet but will not change the number of droplets.

In this scenario, which may be further complicated by coalescence phenomena, the temperature and rate of cooling play a key role in determining how the system responds. In general, different cooling rates can lead to significantly different temporal behaviors related to the formation of the liquid phase (droplets), because the nucleation process is generally non-linear. Without wishing to be bound by theory, it is assumed that cooling can lead to a rapid increase in the number concentration of droplets, followed by a strong, short-lived increase in this growth (nucleation burst). This nucleation burst seems to be more significant at lower temperatures. In addition, it seems that higher cooling rates may favor an earlier start of nucleation. In contrast, a reduction in the cooling rate seems to have a favorable effect on the final size that the aerosol droplets eventually reach.

Therefore, the rapid cooling caused by the entry of external air into the hollow tubular cooling element via the ventilation zone can be advantageously used to facilitate the nucleation and growth of aerosol droplets.However, at the same time, the entry of external air into the hollow tubular cooling element has the direct disadvantage of diluting the aerosol flow delivered to the consumer.

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

The inventors have also surprisingly found that when ventilation levels are within the above ranges, the dilution effect on the aerosol (particularly as can be assessed by measuring the delivery effect of an aerosol former (eg glycerol) included in the aerosol-generating substrate) is advantageously minimized.

In particular, it has been found that aeration levels of between 10% and 20% and even more preferably between 12% and 18% result in particularly satisfactory glycerol delivery values.

Because the ventilated hollow tubular cooling element does not substantially affect the overall RTD of the aerosol-generating article, in an aerosol-generating article according to the invention, the overall RTD of the article can be advantageously fine-tuned by adjusting the length and density of the strips of the aerosol-generating substrate, as well as the length and optional length and density of any segment of filter material forming part of a downstream segment (e.g., such as a downstream filter segment), or the length and density of a segment of filter material disposed upstream of the aerosol-generating substrate. Thus, aerosol-generating articles having a predetermined RTD can be manufactured consistently and with high precision, such that a satisfactory RTD level can be provided to consumers even in the presence of ventilation.

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

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

In certain embodiments, the distance between the downstream end of the strip of the aerosol generating substrate in the ventilation zone is 4 mm to 17 mm, preferably 7 mm to 17 mm, more preferably 10 mm to 17 mm. In other embodiments, the distance between the downstream end of the strip of the aerosol generating substrate in the ventilation zone is 8 mm to 16 mm, preferably 9 mm to 16 mm, more preferably 10 mm to 16 mm. In other embodiments, the distance between the downstream end of the strip of the aerosol generating substrate in the ventilation zone is 8 mm to 15 mm, preferably 9 mm to 15 mm, more preferably 10 mm to 15 mm. For example, the distance between the downstream end of the strip of the aerosol generating substrate in the ventilation zone can be 10 mm to 14 mm, preferably 10 mm to 13 mm, more preferably 10 mm to 12 mm.

Positioning the ventilation zone at a distance within the above range from the downstream end of the strip of aerosol-generating substrate has the benefit of generally ensuring that during use, when the aerosol-generating article is inserted into the heating device, the ventilation zone is just outside the heating device, while reducing the risk of the ventilation zone being inadvertently blocked by the user's lips or hands. In addition, it has been found that positioning the ventilation zone at a distance within the above range from the downstream end of the strip of aerosol-generating substrate can advantageously enhance nucleation and aerosol formation and delivery.

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

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

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

Positioning the ventilation zone at a distance within the above range from the downstream end of the hollow tubular cooling element has the benefit of generally ensuring that during use, when the aerosol-generating article is inserted into the heating device, the ventilation zone is just outside the heating device, while reducing the risk of the ventilation zone being inadvertently blocked by the user's lips or hands. In addition, it has been found that positioning the ventilation zone at a distance within the above range from the downstream end of the hollow tubular cooling element can advantageously result in the formation and delivery of a relatively more uniform aerosol.

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

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

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

Positioning the ventilation zone at a distance within the above range from the downstream end of the aerosol-generating article has the benefit of generally ensuring that during use, when the aerosol-generating article is partially received within the heating device, the portion of the aerosol-generating article extending outside the heating device is long enough for the consumer to comfortably hold the article between their lips, while reducing the risk of the ventilation zone being inadvertently obscured by the user's lips or hands. At the same time, evidence suggests that if the length of the portion of the aerosol-generating article extending outside the heating device is greater, it may become easier to inadvertently and undesirably bend the aerosol-generating article, and this may impair the delivery of the aerosol or generally affect the intended use of the aerosol-generating article.

As discussed in the present disclosure, the downstream segment may include a downstream filter segment. The downstream filter segment may extend to a downstream end of the downstream segment. The downstream filter segment may be located at the downstream end of the aerosol-generating article. The downstream end of the downstream filter segment may define the downstream end of the aerosol-generating article.

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

The downstream filter segment is preferably a solid rod, which may also be described as a "plain" rod and is non-tubular. Thus, the filter segment preferably has a substantially uniform cross-section.

The downstream filter segment is preferably formed of a fibrous filter material. The fibrous filter material can be used to filter the aerosol generated by the aerosol generating substrate. Suitable fibrous filter materials will be known to the skilled person. Particularly preferably, at least one downstream filter segment comprises a cellulose acetate filter segment formed of cellulose acetate tow.

In certain preferred embodiments, the downstream section comprises a single downstream filter segment.In alternative embodiments, the downstream section comprises two or more downstream filter segments axially aligned in end-to-end abutting relationship with each other.

The downstream filter segment may optionally include a flavoring agent, which may be provided in any suitable form. For example, the downstream filter segment may include one or more capsules, beads or particles of a flavoring agent, or one or more threads or wires loaded with a flavoring agent.

Preferably, the downstream filter segment has a low particle filtration efficiency.

Preferably, the downstream filter segment is defined by the stick wrap.Preferably, the downstream filter segment is not ventilated, such that air does not enter the aerosol-generating article along the downstream filter segment.

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

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

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

The resistance to draw (RTD) of the downstream section may be at least 0 mm H ₂ O. The RTD of the downstream section may be at least 3 mm H ₂ O. The RTD of the downstream section may be at least 6 mm H ₂ O.

The RTD of the downstream section may be no greater than 12 mm H ₂ O. The RTD of the downstream section may be no greater than 11 mm H ₂ O. The RTD of the downstream section may be no greater than 10 mm H ₂ O.

The suction resistance of the downstream section may be greater than or equal to 0 mm H ₂ O and less than 12 mm H ₂ O. Preferably, the suction resistance of the downstream section may be greater than or equal to 3 mm H ₂ O and less than 12 mm H ₂ O. The suction resistance of the downstream section may be greater than or equal to 0 mm H ₂ O and less than 11 mm H ₂ O. Even more preferably, the suction resistance of the downstream section may be greater than or equal to 3 mm H ₂ O and less than 11 mm H ₂ O. Even more preferably, the suction resistance of the downstream section may be greater than or equal to 6 mm H ₂ O and less than 10 mm H ₂ O. Preferably, the suction resistance of the downstream section may be 8 mm H ₂ O.

The resistance to draw (RTD) characteristics of the downstream segment may be entirely or primarily attributable to the RTD characteristics of the downstream filter segment of the downstream segment. In other words, the RTD of the downstream filter segment of the downstream segment may entirely define the RTD of the downstream segment.

The downstream filter segment may have a resistance to draw (RTD) of at least 0 mm H ₂ O. The downstream filter segment may have an RTD of at least 3 mm H ₂ O. The downstream filter segment may have an RTD of at least 6 mm H ₂ O.

The RTD of the downstream filter segment may be no greater than 12 mm H ₂ O. The RTD of the downstream filter segment may be no greater than 11 mm H ₂ O. The RTD of the downstream filter segment may be no greater than 10 mm H ₂ O.

The suction resistance of the downstream filter segment may be greater than or equal to 0 mm H ₂ O and less than 12 mm H ₂ O. Preferably, the suction resistance of the downstream filter segment may be greater than or equal to 3 mm H ₂ O and less than 12 mm H ₂ O. The suction resistance of the downstream filter segment may be greater than or equal to 0 mm H ₂ O and less than 11 mm H ₂ O. Even more preferably, the suction resistance of the downstream filter segment may be greater than or equal to 3 mm H ₂ O and less than 11 mm H ₂ O. Even more preferably, the suction resistance of the downstream filter segment may be greater than or equal to 6 mm H ₂ O and less than 10 mm H ₂ O. Preferably, the suction resistance of the downstream filter segment may be 8 mm H ₂ O.

As described above, the downstream filter segment can be formed of a fibrous filter material. The downstream filter segment can be formed of a porous material. The downstream filter segment can be formed of a biodegradable material. The downstream filter segment can be formed of a cellulosic material such as cellulose acetate. For example, the downstream filter segment can be formed of bundled cellulose acetate fibers having a single filament denier between 10 and 15. For example, the downstream filter segment is formed of a relatively low density cellulose acetate tow (such as a cellulose acetate tow comprising fibers having a single filament denier of 12).

The downstream filter segment can be formed by a material based on polylactic acid. The downstream filter segment can be formed by a bioplastic material (preferably a starch-based bioplastic material). The downstream filter segment can be made by injection molding or by extrusion. Bioplastic-based materials are advantageous because they can provide a downstream filter segment structure that is simple and inexpensive to manufacture, has a specific and complex cross-sectional profile, and can include a plurality of relatively large airflow channels extending through the downstream filter segment material, which provides suitable RTD characteristics.

The downstream filter segment may be formed from a sheet of suitable material that has been curled, pleated, gathered, woven or folded into an element defining a plurality of longitudinally extending channels. Such sheets of suitable material may be formed from paper, paperboard, polymers (e.g., polylactic acid), or any other cellulose-based, paper-based, or bioplastic-based material. The cross-sectional profile of such a downstream filter segment may show the channels as being randomly oriented.

The downstream filter segment can be formed in any other suitable manner. For example, the downstream filter segment can be formed by bundles of longitudinally extending tubes. The longitudinally extending tubes can be formed from polylactic acid. The downstream filter segment can be formed by extrusion, molding, lamination, injection molding or shredding of suitable materials. Therefore, it is preferred that there is a low pressure drop (or RTD) from the upstream end of the downstream filter segment to the downstream end of the downstream filter segment.

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

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

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

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

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

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

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

In an embodiment where the downstream section comprises a hollow tubular cooling element and a downstream filter segment, the ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be at least 1.25. In other words, the length of the hollow tubular cooling element may be equal to 125% of the length of the downstream filter segment. The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be at least 1.5. The ratio of the length of the hollow tubular cooling element to the length of the downstream filter segment may be at least 2.

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

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

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

The ventilation zone downstream of the filter segment may include a plurality of perforations. Preferably, the ventilation zone downstream of the filter segment includes at least one row of circumferential perforations. In some embodiments, the ventilation zone downstream of the filter segment may include two rows of circumferential perforations. For example, the perforations may be formed on a production line during manufacture of the aerosol generating article. Preferably, each row of circumferential perforations includes 8 to 30 perforations.

The downstream section may also include one or more additional hollow tubular elements.

In certain embodiments, the downstream section may include a hollow tubular support element upstream of the hollow tubular cooling element described above. Preferably, the hollow tubular support element abuts the downstream end of the strip of aerosol generating substrate. Preferably, the hollow tubular support element abuts the upstream end of the hollow tubular cooling element. Preferably, the hollow tubular support element and the hollow tubular cooling element are adjacent to each other and together provide a hollow tubular section within the downstream section.

The hollow tubular support element may be formed from any suitable material or combination of materials. For example, the support element may be formed from one or more materials selected from the group consisting of: cellulose acetate; paperboard; curled paper, such as curled heat resistant paper or curled parchment paper; and polymeric materials, such as low density polyethylene (LDPE). In a preferred embodiment, the support element is formed from cellulose acetate. Other suitable materials include polyhydroxyalkanoate (PHA) fibers. In a preferred embodiment, the hollow tubular support element comprises a hollow acetate tube.

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

The hollow tubular support element may have an outer diameter between 5 and 10 mm, such as between 5.5 and 9 mm or between 6 and 8 mm. In a preferred embodiment, the hollow tubular support element has an outer diameter of less than 7 mm.

The hollow tubular support element may have a wall thickness of at least 1 mm, preferably at least 1.5 mm, more preferably at least 2 mm.

The hollow tubular support element may have a length of at least 5 mm. Preferably, the support element has a length of at least 6 mm, more preferably at least 7 mm.

The hollow tubular support element may have a length of less than 15 mm. Preferably, the hollow tubular support element has a length of less than 12 mm, more preferably less than 10 mm.

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

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

The length of the hollow tubular section is preferably less than 60 mm. More preferably, the length of the hollow tubular section is less than 55 mm. More preferably, the length of the hollow tubular section is less than 50 mm.

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

Alternatively or in addition to the hollow tubular support element, the downstream section may also include a downstream hollow tubular element downstream of the hollow tubular cooling element. The downstream hollow tubular element may be arranged in close proximity to the hollow tubular cooling element. Alternatively and preferably, the downstream hollow tubular element is separated from the hollow tubular cooling element by at least one other component. For example, the downstream section may include a downstream filter segment between the hollow tubular cooling element and the downstream hollow tubular element. Thus, the downstream hollow tubular element is located downstream of the downstream filter segment, and preferably, the downstream hollow tubular element abuts the downstream end of the downstream filter segment.

Preferably, the downstream hollow tubular element extends to the downstream end of the downstream section. Thus, the downstream hollow tubular element preferably extends to the downstream end of the aerosol generating article. In certain embodiments, additional downstream hollow tubular elements may be provided so that the downstream section comprises two adjacent downstream hollow tubular elements downstream of the downstream filter segment.

The RTD of the downstream hollow tubular element is preferably less than or equal to 10 mm H ₂ O. More preferably, the RTD of the downstream hollow tubular element is less than or equal to 5 mm H ₂ O. Even more preferably, the RTD of the downstream hollow tubular element is less than or equal to 2.5 mm H ₂ O. Even more preferably, the RTD of the downstream hollow tubular element is less than or equal to 2 mm H ₂ O. Even more preferably, the RTD of the downstream hollow tubular element is less than or equal to 1 mm H ₂ O.

The RTD of the downstream hollow tubular element may be at least 0 mm _H2O , or at least 0.25 mm _H2O , or at least 0.5 mm _H2O , or at least 1 mm _H2O .

In some embodiments, the RTD of the downstream hollow tubular element is 0 mmH ₂ O to 10 mmH ₂ O, preferably 0.25 mmH ₂ O to 10 mmH ₂ O, preferably 0.5 mmH ₂ O to 10 mmH ₂ O. In other embodiments, the RTD of the downstream hollow tubular element is 0 mmH ₂ O to 5 mmH ₂ O, preferably 0.25 mmH ₂ O to 5 mmH ₂ O, preferably 0.5 mmH ₂ O to 5 mmH ₂ O. In other embodiments, the RTD of the downstream hollow tubular element is 1 mmH ₂ O to 5 mmH ₂ O. In further embodiments, the RTD of the downstream hollow tubular element is 0 mmH ₂ O to 2.5 mmH ₂ O, preferably 0.25 mmH ₂ O to 2.5 mmH ₂ O, more preferably 0.5 mmH ₂ O to 2.5 mmH ₂ O. In further embodiments, the RTD of the downstream hollow tubular element is 0 _mmH2O to 2 _mmH2O , preferably 0.25 _mmH2O to 2 _mmH2O , more preferably 0.5 _mmH2O to 2 _mmH2O . In particularly preferred embodiments, the RTD of the downstream hollow tubular element is 0 _mmH2O .

Therefore, the flow channel of the downstream hollow tubular element should be free of any components that would hinder the flow of air in the longitudinal direction.Preferably, the flow channel is substantially empty, and particularly preferably the flow channel is empty.

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

The length of the downstream hollow tubular element is preferably less than 20 mm. More preferably, the length of the downstream hollow tubular element is less than 15 mm. More preferably, the length of the downstream hollow tubular element is less than 12 mm. More preferably, the length of the downstream hollow tubular element is less than 10 mm.

For example, the length of the downstream hollow tubular element can be between 3 mm and 20 mm, or between 4 mm and 20 mm, or between 5 mm and 20 mm, or between 6 mm and 20 mm. In other embodiments, the length of the downstream hollow tubular element can be between 3 mm and 15 mm, or between 4 mm and 15 mm, or between 5 mm and 15 mm, or between 6 mm and 15 mm. In other embodiments, the length of the downstream hollow tubular element can be between 3 mm and 12 mm, or between 4 mm and 12 mm, or between 5 mm and 12 mm, or between 6 mm and 12 mm. In other embodiments, the length of the downstream hollow tubular element can be between 3 mm and 10 mm, or between 4 mm and 10 mm, or between 5 mm and 10 mm, or between 6 mm and 10 mm.

In case a downstream hollow tubular element is included in the downstream section, the combined length of the hollow tubular cooling element and the downstream hollow tubular element(s) is preferably at least 20 mm. This corresponds to the sum of the length of the hollow tubular cooling element and the length of the downstream hollow tubular element(s), without taking into account the length of any components provided in between. More preferably, the combined length is at least 30 mm. The combined length may at least be at least 40 mm. More preferably, the combined length is at least 45 mm.

The combined length of the hollow tubular cooling element and the downstream hollow tubular element(s) is preferably less than 60 mm. More preferably, the combined length is less than 55 mm. More preferably, the combined length is less than 50 mm.

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

By providing a combined length within the above ranges, the overall length of the hollow tubular element in the downstream section is relatively long, with the benefits as set out above with respect to the length of the hollow tubular cooling element.

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

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

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

The downstream hollow tubular element may be a paper tube. The downstream hollow tubular element may be a tube formed by spirally winding paper. The downstream hollow tubular element may be formed from multiple paper layers. The paper may have a basis weight of at least 50 g/m2, at least 60 g/m2, at least 70 g/m2, or at least 90 g/m2.

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

Where the downstream hollow tubular element comprises cellulose acetate tow, the cellulose acetate tow may have a denier per filament of between 2 and 4 and a total denier of between 25 and 40.

In case the downstream section further comprises an additional downstream hollow tubular element, as described above, the additional downstream hollow tubular element may be formed of the same material as the downstream hollow tubular element or of a different material.

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

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

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

The distance between the ventilation zone and the upstream end of the downstream hollow tubular element is preferably less than or equal to 10 mm. More preferably, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is less than or equal to 7 mm. Even more preferably, the distance between the ventilation zone and the upstream end of the downstream hollow tubular element is less than or equal to 5 mm.

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

The benefit of positioning the ventilation zone at a distance within the above range from the upstream end of the downstream hollow tubular element is that it generally ensures that during use, when the aerosol generating article is inserted into the heating device, the ventilation zone is just outside the heating device, while reducing the risk of the ventilation zone being inadvertently blocked by the user's lips or hands.

The downstream section may optionally further include an additional cooling element that defines a plurality of longitudinally extending channels so that a large surface area is available for heat exchange. In other words, one such additional cooling element is suitable for acting essentially as a heat exchanger. A plurality of longitudinally extending channels may be defined by a sheet material that has been pleated, gathered or folded to form a channel. A plurality of longitudinally extending channels may be defined by a single sheet that has been pleated, gathered and folded to form a plurality of channels. The sheet may have been curled before pleating, gathering or folding. Alternatively, a plurality of longitudinally extending channels may be defined by a plurality of sheets that have been curled, pleated, gathered and folded to form a plurality of channels. In some embodiments, a plurality of longitudinally extending channels may be defined by a plurality of sheets that have been curled, pleated, gathered or folded together, i.e., defined by two or more sheets that have entered an overlying arrangement and then curled, pleated, gathered or folded into one.

As used herein, the term "curled" means that the sheet has a plurality of substantially parallel ridges or folds. Preferably, when the aerosol-generating article has been assembled, the substantially parallel ridges or folds extend in a longitudinal direction relative to the strip. As used herein, the terms "gathered", "pleated" or "folded" mean that the sheet of material is rolled, folded or otherwise compressed or contracted substantially transversely to the cylindrical axis of the strip. The sheet may be curled before being gathered, pleated or folded. The sheet may be gathered, pleated or folded without prior curling.

One such additional cooling element may have a total surface area of between about 300 square millimeters per millimeter of length and about 1000 square millimeters per millimeter of length.

The additional cooling element preferably provides low resistance to air passing through the additional cooling element. Preferably, the additional cooling element does not substantially affect the resistance to draw of the aerosol-generating article. In order to achieve this, it is preferred that the porosity in the longitudinal direction is greater than 50% and the airflow path through the additional cooling element is relatively unrestricted. The longitudinal porosity of the additional cooling element may be defined by the ratio of the cross-sectional area of the material forming the additional cooling element to the internal cross-sectional area of the aerosol-generating article at the portion containing the additional cooling element.

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

The aerosol-generating article may have an overall length of 45 mm to 100 mm.

Preferably, the overall length of the aerosol-generating article according to the present invention is at least 50 mm. More preferably, the overall length of the aerosol-generating article according to the present invention is at least 60 mm. Even more preferably, the overall length of the aerosol-generating article according to the present invention is at least 70 mm.

The overall length of the aerosol-generating article according to the present invention is preferably less than or equal to 90 mm. More preferably, the overall length of the aerosol-generating article according to the present invention is preferably less than or equal to 85 mm. Even more preferably, the overall length of the aerosol-generating article according to the present invention is preferably less than or equal to 80 mm.

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

The aerosol-generating article preferably has an outer diameter of at least 5 mm along the full length of the article. Where the diameter varies along the length of the aerosol-generating article, the outer diameter is preferably at least 5 mm at all locations along the length of the article.

Preferably, the aerosol-generating article has an outer diameter along the full length of the article of at least 5.5 mm. More preferably, the aerosol-generating article has an outer diameter along the full length of the article of at least 6 mm.

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

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

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

In particularly preferred embodiments, one or more of the components of the aerosol-generating article is individually defined by its own wrapper.

In an embodiment, the strip of aerosol-generating substrate and the downstream filter segment are packaged separately. The upstream element, the strip of aerosol-generating substrate and the hollow tubular element are then combined with an outer wrapper. Subsequently, they are combined with the downstream filter segment having its own wrapper by means of tipping paper.

Preferably, at least one component of the aerosol-generating article is packaged in a hydrophobic wrapper.

The term "hydrophobic" refers to a surface that exhibits water repellent properties. A useful method for determining this is to measure the water contact angle. The "water contact angle" is the angle conventionally measured across a liquid when a liquid/vapor interface encounters a solid surface. It quantifies the wettability of a solid surface by a liquid via Young's equation. Hydrophobicity or water contact angle can be determined by utilizing the TAPPI T558 test method, and the results are presented as the interfacial contact angle and are reported in "degrees," and can range from near zero to near 180 degrees.

In a preferred embodiment, 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.

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

In a particularly preferred embodiment, the aerosol-generating article according to the present invention comprises an upstream element arranged in a linear sequence, a strip of aerosol-generating substrate positioned immediately downstream of the upstream element, a hollow tubular cooling element positioned immediately downstream of the strip of aerosol-generating substrate, a downstream filter segment positioned immediately downstream of the hollow tubular cooling element, a downstream hollow tubular element positioned immediately downstream of the downstream filter segment, and one or more outer packagings combining the above components. The upstream element defines the upstream section of the aerosol-generating article. The hollow tubular cooling element, the downstream filter segment and the downstream hollow tubular element form the downstream section of the aerosol-generating article.

The strips of aerosol-generating substrate may abut the upstream element. The hollow tubular cooling element may abut the strips of aerosol-generating substrate. The downstream filter segment may abut the hollow tubular cooling element. The downstream hollow tubular element may abut the downstream filter segment. Preferably, the hollow tubular cooling element abuts the strips of aerosol-generating substrate, the downstream filter segment abuts the hollow tubular cooling element, and the downstream hollow tubular element abuts the downstream filter segment.

The present disclosure 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 include a body. The body or housing of the aerosol generating device may define a device cavity for removably receiving an aerosol generating article at the mouth end of the device. The aerosol generating device may include a heating element or heater for heating an aerosol generating substrate when the aerosol generating article is received in the device cavity.

The device cavity may be referred to as a heating chamber of the aerosol-generating device. The device cavity may extend between a distal end and an oral end or a proximal end. The distal end of the device cavity may be a closed end, and the oral end or the proximal end of the device cavity may be an open end. The aerosol-generating article may be inserted into the device cavity or the heating chamber via the open end of the device cavity. The device cavity may be cylindrical so as to conform to the same shape of the aerosol-generating article.

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

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

The length of the device cavity (or heating chamber) may be equal to or greater than the length of the strip of the aerosol generating substrate. The length of the device cavity may be equal to or greater than the combined length of the upstream section or element and the strip of the aerosol generating substrate. Preferably, the length of the device cavity is such that when the aerosol generating article is received in the aerosol generating device, at least 75% of the length of the strip of the aerosol generating substrate is inserted or received in the device cavity. More preferably, the length of the device cavity is such that when the aerosol generating article is received in the aerosol generating device, at least 80% of the length of the strip of the aerosol generating substrate is inserted or received in the device cavity. More preferably, the length of the device cavity is such that when the aerosol generating article is received in the aerosol generating device, at least 90% of the length of the strip of the aerosol generating substrate is inserted or received in the device cavity. This maximizes the length of the strip of the aerosol generating substrate, and the aerosol generating substrate can be heated along the length during use, thereby optimizing the generation of aerosol from the aerosol generating substrate and reducing tobacco waste.

The length of the device cavity may be such that the downstream segment or a portion thereof is configured to protrude from the device cavity when the aerosol-generating article is received in the device cavity. The length of the device cavity may be such that a portion of the downstream segment (such as a hollow tubular cooling element or a downstream filter segment) is configured to protrude from the device cavity when the aerosol-generating article is received in the device cavity. The length of the device cavity may be such that a portion of the downstream segment (such as a hollow tubular cooling element or a downstream filter segment) is configured to be received in the device cavity when the aerosol-generating article is received in the device cavity.

When the aerosol-generating article is received in the device, at least 25% of the length of the downstream segment may be inserted or received in the device cavity.When the aerosol-generating article is received in the device, at least 30% of the length of the downstream segment may be inserted or received in the device cavity.

When the aerosol-generating article is received in the device, at least 30% of the length of the hollow tubular element can be inserted or received in the device cavity. When the aerosol-generating article is received in the device, at least 40% of the length of the hollow tubular element can be inserted or received in the device cavity. When the aerosol-generating article is received in the device, at least 50% of the length of the hollow tubular element can be inserted or received in the device cavity. Hollow tubular elements of various lengths are described in more detail in the present disclosure.

Optimizing the amount or length of the article inserted into the aerosol-generating device may enhance resistance to accidental dropping of the article during use. In particular, during heating of the aerosol-generating substrate, the substrate may shrink such that its outer diameter may decrease, thereby reducing the extent to which an insertion portion of the article inserted into the device may frictionally engage with the device cavity. The insertion portion of the article, or the portion of the article configured to be received within the device cavity, may be the same length as the device cavity.

The length of the device cavity may be between 15 mm and 80 mm. Preferably, the length of the device cavity is between 20 mm and 70 mm. More preferably, the length of the device cavity is between 25 mm and 60 mm. More preferably, the length of the device is between 25 mm and 50 mm.

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

The diameter of the device lumen may be between 4 mm and 10 mm. The diameter of the device lumen may be between 5 mm and 9 mm. The diameter of the device lumen may be between 6 mm and 8 mm. The diameter of the device lumen may be between 6 mm and 7 mm.

The diameter of the device cavity may be substantially equal to or greater than the diameter of the aerosol-generating article.The diameter of the device cavity may be the same as the diameter of the aerosol-generating article so as to establish a close fit with the aerosol-generating article.

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

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

With such an airtight configuration, there will be substantially no gaps or empty spaces between the peripheral wall defining the device cavity and the aerosol-generating article for air to flow through.

The close fit with the aerosol-generating article may be established along the entire length of the device cavity or along a portion of the length of the device cavity.

The aerosol generating device may include an airflow channel extending between a channel inlet and a channel outlet. The airflow channel may be configured to establish fluid communication between the interior of the device cavity and the exterior of the aerosol generating device. The airflow channel of the aerosol generating device may be defined within a housing of the aerosol generating device to enable fluid communication between the interior of the device cavity and the exterior of the aerosol generating device. When the aerosol generating article is received in the device cavity, the airflow channel may be configured to provide airflow into the article so as to deliver the generated aerosol to a user who draws from the mouth end of the article.

The airflow passage of the aerosol generating device may be defined within or by the peripheral wall of the housing of the aerosol generating device. In other words, the airflow passage of the aerosol generating device may be defined within the thickness of the peripheral wall or by the inner surface of the peripheral wall, or a combination of both. The airflow passage 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 the peripheral boundary of the device cavity.

The airflow channel of the aerosol generating device may extend from an inlet at the mouth or proximal end of the aerosol generating device to an outlet distal to the mouth end of the device.The airflow channel may extend in 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 may externally heat the aerosol-generating article when the aerosol-generating article is received in the aerosol-generating device.Such an external heater may confine the aerosol-generating article when the aerosol-generating article is inserted into or received in the aerosol-generating device.

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

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

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

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

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

The electrically insulating substrate may include any suitable material. For example, the electrically insulating substrate may include one or more of: paper, glass, ceramic, anodized metal, coated metal, and polyimide. The ceramic may include mica, aluminum oxide (Al ₂ O ₃ ) or zirconium oxide (ZrO ₂ ). Preferably, the electrically insulating substrate has a thermal conductivity of less than or equal to about 40 W/m·Kelvin, preferably less than or equal to about 20 W/m·Kelvin, and ideally less than or equal to about 2 W/m·Kelvin.

The heater may comprise a heating element comprising a rigid electrically insulating substrate having one or more conductive tracks or wires disposed on its surface. The size and shape of the electrically insulating substrate may allow 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 reinforcement means. An electric current may be passed through the one or more conductive tracks 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 include an inductor coil and a power supply configured to provide a high-frequency oscillating current to the inductor coil. As used herein, a high-frequency oscillating current means an oscillating current having a frequency between about 500 kHz and about 30 MHz. Advantageously, the heater may include a DC/AC inverter for converting a DC current supplied by a DC power supply into an alternating current. The inductor coil may be arranged to generate a high-frequency oscillating electromagnetic field when receiving the high-frequency oscillating current from the power supply. The inductor coil may be arranged to generate a high-frequency oscillating electromagnetic field in a device cavity. In some embodiments, the inductor coil may substantially define the device cavity. The inductor coil may extend at least partially along the length of the device cavity.

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

The susceptor element may be arranged such that when the aerosol generating article is received in the cavity of the aerosol generating device, the oscillating electromagnetic field generated by the inductor coil induces a current in the susceptor element, thereby causing the susceptor element to heat up. In these embodiments, the aerosol generating device is preferably capable of generating a fluctuating electromagnetic field having a magnetic field strength (H field strength) of between 1 kiloamperes per meter and 5 kiloamperes per meter (kA m), preferably between 2 kA/m and 3 kA/m, for example about 2.5 kA/m. Preferably, the electrically operated aerosol generating device is capable of generating a fluctuating electromagnetic field having a frequency of between 1 MHz and 30 MHz, for example between 1 MHz and 10 MHz, for example between 5 MHz and 7 MHz.

In these embodiments, the susceptor element is preferably positioned to contact the aerosol generating substrate. In some embodiments, the susceptor element is located in the aerosol generating device. In these embodiments, the susceptor element may be located in a cavity. The aerosol generating device may include only one susceptor element. The aerosol generating device may include a plurality of susceptor elements. In some embodiments, the susceptor element is preferably arranged to heat the outer surface of the aerosol generating substrate.

The susceptor element may comprise any suitable material. The susceptor element may be formed of any material that can be inductively heated to a temperature sufficient to release volatile compounds from the aerosol generating substrate. Suitable materials for the elongated susceptor element include graphite, molybdenum, silicon carbide, stainless steel, niobium, aluminum, nickel, nickel-containing compounds, titanium, and metal material composites. Some susceptor elements include metal or carbon. Advantageously, the susceptor element may include or consist of a ferromagnetic material, such as ferritic iron, ferromagnetic alloys (e.g., ferromagnetic steel or stainless steel), ferromagnetic particles, and ferrites. Suitable susceptor elements may be aluminum or include aluminum. The susceptor element preferably comprises about greater than 5%, preferably greater than 20%, more preferably greater than 50% or greater than 90% ferromagnetic or paramagnetic material. Some elongated susceptor elements may be heated to a temperature in excess of 250 degrees Celsius.

The susceptor element may comprise a non-metallic core with a metallic layer disposed thereon.For example, the susceptor element may comprise a metallic track 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 within a limited operating temperature range below the maximum operating temperature. An operating temperature range between about 150 degrees Celsius and about 300 degrees Celsius in the heating chamber (or device cavity) is preferred. The operating temperature range of the heater may be between about 150 degrees Celsius and about 250 degrees Celsius.

Preferably, the operating temperature range of the heater may be between about 150 degrees Celsius and about 200 degrees Celsius. More preferably, the operating temperature range of the heater may be between about 180 degrees Celsius and about 200 degrees Celsius. In particular, it has been found that optimal and consistent aerosol delivery can be achieved when using an aerosol generating device with an external heater having an operating temperature range between about 180 degrees Celsius and about 200 degrees Celsius, wherein the aerosol generating article has a relatively low RTD (e.g., a downstream segment RTD of less than 15 mm _H2O ) as described in the present disclosure.

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

When the article is received in the device cavity, the ventilation zone may be positioned at least 0.5 mm away from the mouth end (or mouth end face) of the device cavity or the device itself (in the downstream direction of the article). When the article is received in the device cavity, the ventilation zone may be positioned at least 1 mm away from the mouth end (or mouth end face) of the device cavity or the device itself (in the downstream direction of the article). When the article is received in the device cavity, the ventilation zone may be positioned at least 2 mm away from the mouth end (or mouth end face) of the device cavity or the device itself (in the downstream direction of the article).

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 1.03 to 1.13.

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

The aerosol generating device may include a power source. The power source may be a DC power source. In some embodiments, the power source is a battery. The power source may be a nickel metal hydride battery, a nickel cadmium battery, or a lithium-based battery, such as a lithium cobalt battery, a lithium iron phosphate battery, or a lithium polymer battery. However, in some embodiments, the power source may be another form of charge storage device, such as a capacitor. The power source may need to be recharged and may have a capacity that allows storage of enough energy for one or more user operations (e.g., one or more aerosol generating experiences). For example, the power source may have sufficient capacity to allow continuous heating of the aerosol generating substrate for a period of about six minutes, corresponding to the typical time spent smoking a conventional cigarette, or for a period of time that is a multiple of six minutes. In another example, the power source may have sufficient capacity to allow a predetermined number of puffs or discontinuous activation of the heater.

A non-exhaustive list of non-limiting examples is provided below.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 strip of an aerosol-generating substrate.

EX2. An aerosol-generating article according to example EX1, wherein the strip of aerosol-generating substrate has a length of at least 17 mm.

EX3. An aerosol-generating article according to any preceding example, wherein the rod of aerosol-generating substrate comprises tobacco material.

EX4. An aerosol-generating article according to example EX3, wherein the tobacco material has a density of less than 350 mg/cm3.

EX5. An aerosol-generating article according to example EX4, wherein the tobacco material has a density of less than 300 mg/cm3.

EX6. An aerosol-generating article according to example EX3, EX4 or EX5, wherein the tobacco material has a density of at least 100 mg/cm3.

EX7. An aerosol-generating article according to example EX3, wherein the tobacco material has a density between 150 mg/cm3 and 500 mg/cm3.

EX8. An aerosol-generating article according to example EX7, wherein the tobacco material has a density between 200 mg/cm3 and 400 mg/cm3.

EX9. An aerosol-generating article according to any preceding example, comprising a downstream section disposed downstream of the strip of aerosol-generating substrate.

EX10. An aerosol-generating article according to example EX9, wherein the downstream section comprises a hollow tubular element adjacent to the downstream end of the strip of aerosol-generating substrate.

EX11. An aerosol-generating article according to example EX10, wherein the hollow tubular element has a length of at least 40 mm.

EX12. An aerosol-generating article according to example EX9, wherein the downstream section comprises a downstream filter segment.

EX13. An aerosol-generating article according to example EX12, wherein the downstream segment comprises a ventilation zone located at a position downstream of the downstream filter segment.

EX14. An aerosol-generating article according to example EX12 or EX13, wherein the downstream filter segment is a solid rod.

EX15. An aerosol-generating article according to any of examples EX12 to EX14, comprising a downstream hollow tubular element located downstream of the downstream filter segment.

EX16. An aerosol-generating article according to example EX15, wherein the downstream hollow tubular element is adjacent to the downstream end of the downstream filter segment.

EX17. An aerosol-generating article according to example EX15 or EX16, wherein the ventilation zone is at a position along the downstream hollow tubular element.

EX18. An aerosol-generating article according to example EX17, wherein the ventilation zone is located towards the upstream end of the downstream hollow tubular element.

EX19. The aerosol-generating article according to any of examples EX12 to EX18, wherein the downstream section comprises a hollow tubular cooling element, and wherein the downstream filter segment abuts a downstream end of the hollow tubular cooling element.

EX20. An aerosol-generating article according to any one of examples EX12 to EX19, wherein the downstream filter segment has a length of at least 5 mm.

EX21. An aerosol-generating article according to any one of examples EX12 to EX20, wherein the downstream filter segment has a length less than or equal to 20 millimeters.

EX22. An aerosol-generating article according to any of examples EX12 or EX21, wherein the downstream filter segment has a length between 5 mm and 20 mm.

EX23. An aerosol-generating article according to example EX9, wherein the downstream section extends to a downstream end of the aerosol-generating article.

EX24. An aerosol-generating article according to example EX9 or EX23, wherein the downstream section comprises a hollow tubular cooling element.

EX25. An aerosol-generating article according to example EX24, wherein the hollow tubular cooling element has a length of at least 20 mm.

EX26. An aerosol-generating article according to example EX25, wherein the hollow tubular cooling element has a length of at least 25 mm.

EX27. An aerosol-generating article according to any one of examples EX24 to EX26, wherein the hollow tubular cooling element has a length less than or equal to 50 mm.

EX28. An aerosol-generating article according to example EX27, wherein the hollow tubular cooling element has a length between 20 mm and 50 mm.

EX29. An aerosol-generating article according to any one of examples EX9 or EX23 to EX26, wherein the downstream segment has a length of at least 45 millimeters.

EX30. An aerosol-generating article according to any preceding example, wherein the maximum outer diameter of the aerosol-generating article is less than 8 mm.

EX31. An aerosol-generating article according to example EX30, wherein the aerosol-generating article has a maximum outer diameter of between 5 mm and 8 mm.

EX32. An aerosol-generating article according to example EX30 or EX31, wherein the aerosol-generating article has a maximum outer diameter less than or equal to 7 mm.

EX33. An aerosol-generating article according to example EX32, wherein the aerosol-generating article has a maximum outer diameter of between 5.5 mm and 7 mm.

EX34. An aerosol-generating article according to example EX9, wherein a ratio of the length of the downstream segment to the length of the strip of the aerosol-generating substrate is at least 1.5.

EX35. An aerosol-generating article according to example EX9, wherein a ratio of the length of the downstream segment to the total length of the aerosol-generating article is at least 0.6.

EX36. An aerosol-generating article according to any preceding example, wherein the aerosol-generating article has an overall length of at least 50 mm.

EX37. An aerosol-generating article according to any preceding example, wherein the strip of aerosol-generating substrate has a length less than or equal to 40 mm.

EX38. An aerosol-generating article according to example EX37, wherein the strip of aerosol-generating substrate has a length less than or equal to 36 millimeters.

EX39. An aerosol-generating article according to any preceding example, wherein the strip of aerosol-generating substrate has a length less than or equal to 30 mm.

EX40. An aerosol-generating article according to any preceding example, wherein the strip of aerosol-generating substrate has a length less than or equal to 25 millimeters.

EX41. An aerosol-generating article according to any preceding example, wherein the strip of aerosol-generating substrate has a length less than or equal to 20 mm.

EX42. The aerosol-generating article according to any preceding example, wherein a ratio of the length of the strip of the aerosol-generating substrate to the total length of the aerosol-generating article is less than or equal to 0.4.

EX43. An aerosol-generating article according to any preceding example, wherein the strip of aerosol-generating substrate has a length of at least 17 millimeters.

EX44. An aerosol-generating article according to any preceding example, wherein the strip of aerosol-generating substrate has a length of at least 20 millimeters.

EX45. An aerosol-generating article according to any preceding example, wherein the strip of aerosol-generating substrate has a length of at least 25 mm.

EX46. An aerosol-generating article according to any preceding example, wherein the strip of aerosol-generating substrate has a length of at least 29 millimeters.

EX47. An aerosol-generating article according to any preceding example, wherein the strip of aerosol-generating substrate has a length between 29 mm and 36 mm.

EX48. An aerosol-generating article according to any preceding example, comprising an upstream element.

EX49. An aerosol-generating article according to example EX48, wherein the upstream element is disposed upstream of the strip of aerosol-generating substrate.

EX50. An aerosol-generating article according to example EX48 or EX49, wherein the upstream element is disposed adjacent to the upstream end of the strip of aerosol-generating substrate.

EX51. An aerosol-generating article according to any one of examples EX48 to EX50, wherein the upstream element has a length between 2 mm and 8 mm.

EX52. An aerosol-generating article according to any one of examples EX48 to EX51, wherein the upstream element has a length between 2 mm and 6 mm.

EX53. An aerosol-generating article according to any one of examples EX48 to EX52, wherein the upstream element has a length between 4 mm and 6 mm.

EX54. An aerosol-generating article according to any of examples EX48 to EX53, wherein the upstream element comprises a hollow support segment having a central longitudinal cavity extending through the hollow support segment.

EX55. An aerosol-generating article according to example EX54, wherein the hollow tubular support element has a wall thickness of less than 1 mm.

EX56. The aerosol-generating article according to one of examples EX48 to EX55, wherein the resistance to draw (RTD) of the upstream element is less than or equal to 10 mm _H20 .

EX57. An aerosol-generating article according to any preceding example, wherein the aerosol-generating article has an overall length of at least 60 mm.

EX58. An aerosol-generating article according to example EX57, wherein the aerosol-generating article has an overall length of at least 65 mm.

EX59. An aerosol-generating article according to any preceding example, wherein the aerosol-generating article has an overall length less than or equal to 90 mm.

EX60. An aerosol-generating article according to any preceding example, wherein the aerosol-generating article has an overall length of between 65 mm and 90 mm.

EX61. An aerosol-generating article according to any preceding example, wherein the strip of aerosol-generating substrate comprises one or more aerosol formers.

EX62. An aerosol-generating article according to example EX61, wherein the strip of aerosol-generating substrate has an aerosol former content of less than or equal to 30 wt.-% on a dry weight basis.

EX63. An aerosol-generating article according to example EX62, wherein the strip of aerosol-generating substrate has an aerosol former content of less than or equal to 20 wt.-% on a dry weight basis.

EX64. An aerosol-generating article according to example EX63, wherein the strip of aerosol-generating substrate has an aerosol former content of less than or equal to 10 wt.-% on a dry weight basis.

EX65. An aerosol-generating article according to example EX62, wherein the strip of aerosol-generating substrate has an aerosol former content of between 10 wt% and 30 wt% on a dry weight basis.

EX66. The aerosol-generating article according to any one of examples EX61 to EX65, wherein the one or more aerosol formers include one or more of glycerol and propylene glycol.

EX67. The aerosol-generating article according to any preceding example, wherein a ratio of the length of the upstream element to the length of the hollow tubular element of the downstream section is between 0.01 and 0.15.

EX68. An aerosol-generating article according to any one of examples EX3 to EX67, wherein the tobacco material comprises shredded tobacco material.

EX69. An aerosol-generating article according to any preceding example, wherein the ratio of the length of the strip of the aerosol-generating substrate to the total length of the aerosol-generating article is at least 0.2, preferably 0.25.

EX70. An aerosol generating system, the aerosol generating system comprising:

An aerosol-generating article according to any preceding example; and

An aerosol-generating device comprises a heating chamber for receiving the aerosol-generating article and at least a heating element arranged at or around a periphery of the heating chamber.

In the following, the present invention will be further described with reference to the figures of the accompanying drawings, in which:

FIG1 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

FIG2 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

3a and 3b show schematic side cross-sectional views of aerosol-generating articles according to the present disclosure;

4a and 4b show schematic side cross-sectional views of aerosol-generating articles according to the present disclosure;

FIG5 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

FIG6 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

FIG7 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

FIG8 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

FIG9 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

FIG10 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

FIG11 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

FIG12 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

FIG13 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

FIG14 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure;

FIG15 shows a schematic side cross-sectional view of an aerosol-generating article according to the present disclosure; and

16 shows a schematic side cross-sectional view of an aerosol-generating system comprising an aerosol-generating device and an aerosol-generating article according to the present disclosure.

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

Each component of the aerosol-generating article shown in the figures and described in the present disclosure may be defined by a corresponding wrapper, or may be linked together by one or more wrappers not shown in the figures. Unless otherwise specified, the maximum outer diameter of each of the aerosol-generating articles shown in the figures is about 6.5 mm.

The rod 12 of aerosol-generating substrate is defined by a wrapper (not shown) and includes at least one aerosol-generating substrate type described in the present disclosure, such as plant cut filler (particularly tobacco cut filler), homogenized tobacco, a gel preparation, or a homogenized plant material including particles of plants other than tobacco. The rods 12 of the aerosol-generating articles shown in all figures have an average tobacco density of about 250 mg/cm3.

The downstream section 14 of the aerosol generating article 10 shown in Figure 1 includes a hollow tubular cooling element 22, a downstream filter segment 24, and a downstream end or mouth end hollow tubular element 26. The hollow tubular cooling element 22 is positioned immediately downstream of the strip 12 of the aerosol generating substrate. In other words, the hollow tubular cooling element 22 is adjacent to the downstream end of the strip 12. The downstream filter segment 24 is adjacent to the downstream end of the hollow tubular cooling element 22, and the downstream hollow tubular element 26 is adjacent to the downstream end of the downstream filter segment 24. Therefore, the downstream filter segment 24 is located between the hollow tubular cooling element 22 and the downstream hollow tubular element 26. The downstream end 19 of the article 10 is defined by the downstream end of the downstream hollow tubular element 26.

The length of the strip 12 of aerosol-generating substrate is approximately 40 mm.

The hollow tubular cooling element 22 is provided in the form of a hollow cylindrical tube made of paperboard or cellulose acetate. The hollow tubular cooling segment 22 defines an inner cavity extending from the upstream end of the hollow tubular cooling element 22 to the downstream end of the hollow tubular cooling element 22. The inner cavity is substantially empty, and thus substantially unrestricted airflow is achieved along the inner cavity. The hollow tubular cooling element 22 may not substantially affect the overall RTD of the aerosol-generating article 10. The length of the hollow tubular cooling element 22 is about 25 mm. The wall thickness of the hollow tubular cooling element 22 is about 250 micrometers (µm).

The downstream filter segment 24 comprises a cylindrical rod of cellulose acetate tow. The length of the downstream filter segment 24 is approximately 10 mm.

The downstream hollow tubular element 26 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The downstream hollow tubular element 26 defines an inner cavity extending from the upstream end of the downstream hollow tubular element 26 to the downstream end of the downstream hollow tubular element 26. The inner cavity is substantially empty, and thus substantially unrestricted airflow is achieved along the inner cavity. The downstream hollow tubular element 26 does not substantially affect the overall RTD of the aerosol-generating article 10. The length of the downstream hollow tubular element 26 is about 6 mm. The wall thickness of the downstream hollow tubular element 26 is about 1 mm.

The aerosol-generating article 10 includes a ventilation zone 36 disposed at a location along the hollow tubular cooling element 22. The ventilation zone 36 includes at least one row of circumferential perforations extending through the outer peripheral wall of the hollow tubular cooling element 22 and any wrapper (not shown) defining the hollow tubular cooling element 22. The ventilation zone 36 is disposed approximately 2 mm from the downstream end of the hollow tubular cooling element 22.

The aerosol-generating article 101 shown in Figure 2 is similar to the aerosol-generating article 10 shown in Figure 1 and differs only in the following respects. The strip 12 of aerosol-generating substrate is shorter and the hollow tubular cooling element 22 is longer. The length of the strip 12 of aerosol-generating substrate is about 25 mm. The length of the hollow tubular cooling element 22 is about 40 mm.

The aerosol generating article 102 shown in Figure 3a is similar to the aerosol generating article 101 shown in Figure 2 and differs only in the following respects. The hollow tubular cooling element 22 is shorter and the downstream hollow tubular element 27 is longer. The length of the hollow tubular cooling element 22 is about 25 mm. The length of the downstream hollow tubular element 27 is about 20 mm. In addition, a ventilation zone 36 is provided along the downstream hollow tubular element 27. The ventilation zone 36 is provided about 2 mm from the upstream end of the downstream hollow tubular element 26. The ventilation zone 36 includes at least one row of circumferential perforations extending through the outer peripheral wall of the downstream hollow tubular element 27 and any wrapper (not shown) that defines the downstream hollow tubular element 27.

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

In FIG. 3 b , the first hollow tubular segment 271 is provided in the form of a hollow cylindrical tube made of paperboard. The first hollow tubular segment 271 defines an inner cavity extending from the upstream end of the first hollow tubular segment 271 to the downstream end of the first hollow tubular segment 271. The inner cavity is substantially empty, and thus substantially unrestricted airflow is achieved along the inner cavity. The first hollow tubular segment 271 may not substantially affect the overall RTD of the aerosol generating article 103. The length of the first hollow tubular segment 271 is about 10 mm. The wall thickness of the first hollow tubular segment 271 is about 250 micrometers (μm). The ventilation zone 36 is provided at about 2 mm from the upstream end of the first hollow tubular segment 271 of the downstream hollow tubular element 27.

In FIG3 b , the second hollow tubular segment 272 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The second hollow tubular segment 272 defines an inner cavity extending from the upstream end of the second hollow tubular segment 272 to the downstream end of the second hollow tubular segment 272. The inner cavity is substantially empty, and thus substantially unrestricted airflow is achieved along the inner cavity. The second hollow tubular segment 272 does not substantially affect the overall RTD of the aerosol generating article 103. The length of the second hollow tubular segment 272 is about 10 mm. The wall thickness of the second hollow tubular segment 272 is about 1 mm.

The aerosol generating articles 104, 105 shown in Figures 4a and 4b are similar to the aerosol generating article 101 shown in Figure 2, and differ only in that the aerosol generating articles 104, 105 also include an upstream section 16 located upstream of the strip 12 of the aerosol generating substrate. The distal end 18 of the articles 104, 105 is defined by the upstream end of the upstream section 16. The upstream section 16 includes upstream elements 341, 342 adjacent to the upstream end of the strip 12. The length of the upstream elements 341, 342 is about 5mm. In the article 104 shown in Figure 4a, the upstream element 341 is arranged in the form of a cylindrical rod of cellulose acetate tow. In the article 105 shown in Figure 4b, the upstream element 342 is arranged in the form of a hollow cylindrical tube made of cellulose acetate, having a wall thickness of about 1mm.

The downstream section 14 of the aerosol generating article 20 shown in Figure 5 includes a hollow tubular support element 28, a cooling element 32 and a downstream filter segment 24. The hollow tubular support element 28 is positioned immediately downstream of the strip 12 of the aerosol generating substrate. In other words, the hollow tubular support element 28 is adjacent to the downstream end of the strip 12. The cooling element 32 is adjacent to the downstream end of the hollow tubular support element 28, and the downstream filter segment 24 is adjacent to the downstream end of the cooling element 32. Therefore, the cooling element 32 is located between the hollow tubular support element 28 and the downstream filter segment 24. The downstream end 19 of the article 20 is defined by the downstream end of the downstream filter segment 24.

The length of the strip 12 of aerosol-generating substrate is approximately 25 mm.

The hollow tubular support element 28 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The hollow tubular support element 28 defines an inner cavity extending from the upstream end of the hollow tubular support element 28 to the downstream end of the hollow tubular support element 28. The inner cavity is substantially empty, and thus substantially unrestricted airflow is achieved along the inner cavity. The hollow tubular support element 28 may not substantially affect the overall RTD of the aerosol-generating article 20. The length of the hollow tubular support element 28 is about 8 mm. The wall thickness of the hollow tubular support element 28 is about 1.5 mm.

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

The downstream filter segment 24 comprises a cylindrical rod of cellulose acetate tow. The length of the downstream filter segment 24 is about 7 mm.

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

The aerosol-generating article 201 shown in FIG6 is similar to the aerosol-generating article 20 shown in FIG5 and differs in that it further comprises a hollow tubular cooling element 22 and the strip 12 of aerosol-generating substrate is shorter. The length of the strip 12 of aerosol-generating substrate is about 12 mm. The hollow tubular cooling element 22 is positioned immediately downstream of the cooling element 32 and immediately upstream of the downstream filter segment 24. In other words, the hollow tubular cooling element 22 abuts the cooling element 32 and the downstream filter segment 24.

The hollow tubular cooling element 22 is provided in the form of a hollow cylindrical tube made of paperboard. The hollow tubular cooling segment 22 defines an inner cavity extending from the upstream end of the hollow tubular cooling element 22 to the downstream end of the hollow tubular cooling element 22. The inner cavity is substantially empty, and thus substantially unrestricted airflow is achieved along the inner cavity. The hollow tubular cooling element 22 may not substantially affect the overall RTD of the aerosol generating article 201. The length of the hollow tubular cooling element 22 is about 25 mm. The wall thickness of the hollow tubular cooling element 22 is about 250 micrometers (µm).

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

The downstream hollow tubular element 27 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The downstream hollow tubular element 27 defines an inner cavity extending from the upstream end of the downstream hollow tubular element 27 to the downstream end of the downstream hollow tubular element 27. The inner cavity is substantially empty, and thus substantially unrestricted airflow is achieved along the inner cavity. The downstream hollow tubular element 27 may not substantially affect the overall RTD of the aerosol-generating article 202. The length of the downstream hollow tubular element 27 is about 5 mm. The wall thickness of the downstream hollow tubular element 27 is about 1 mm.

The aerosol-generating article 30 shown in Figure 8 comprises a strip of aerosol-generating substrate 12 and a downstream section 14 located downstream of the strip of aerosol-generating substrate 12. In addition, the aerosol-generating article 30 comprises an upstream section 16 located upstream of the strip of aerosol-generating substrate 12. The distal end 18 of the article 30 is defined by the upstream end of the upstream section 16.

The downstream section 14 of the aerosol generating article 30 shown in Figure 8 includes a hollow tubular cooling element 22 and a downstream filter segment 24. The hollow tubular cooling element 22 is positioned immediately downstream of the strip 12 of the aerosol generating substrate. In other words, the hollow tubular cooling element 22 is adjacent to the downstream end of the strip 12. The downstream filter segment 24 is adjacent to the downstream end of the hollow tubular cooling element 22. Therefore, the hollow tubular cooling element 22 is located between the strip 12 and the downstream filter segment 24. The downstream end 19 of the article 30 is defined by the downstream end of the downstream filter segment 24.

The length of the strip 12 of aerosol-generating substrate is approximately 25 mm.

The hollow tubular cooling element 22 is provided in the form of a hollow cylindrical tube made of paperboard or cellulose acetate. The hollow tubular cooling segment 22 defines an inner cavity extending from the upstream end of the hollow tubular cooling element 22 to the downstream end of the hollow tubular cooling element 22. The inner cavity is substantially empty, and thus substantially unrestricted airflow is achieved along the inner cavity. The hollow tubular cooling element 22 may not substantially affect the overall RTD of the aerosol-generating article 30. The length of the hollow tubular cooling element 22 is about 21 mm. The wall thickness of the hollow tubular cooling element 22 is about 250 micrometers (µm).

The downstream filter segment 24 comprises a cylindrical rod of cellulose acetate tow. The length of the downstream filter segment 24 is about 7 mm.

The upstream section 16 comprises an upstream element 341 adjacent the upstream end of the strip 12. The upstream element 341 is provided in the form of a cylindrical rod of cellulose acetate tow. The length of the upstream element 341 is about 5 mm.

The aerosol-generating article 30 includes a ventilation zone 36 disposed at a location along the hollow tubular cooling element 22. The ventilation zone 36 includes at least one row of circumferential perforations extending through the outer peripheral wall of the hollow tubular cooling element 22 and any wrapper (not shown) defining the hollow tubular cooling element 22. The ventilation zone 36 is disposed approximately 2 mm from the downstream end of the hollow tubular cooling element 22.

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

The aerosol-generating article 302 shown in FIG10 is similar to the aerosol-generating article 301 shown in FIG8 , and differs in that the strip 12 is shorter and the hollow tubular cooling element 22 is longer, and the article 302 further comprises a downstream hollow tubular element 27. In FIG10 , the length of the strip 12 of the aerosol-generating substrate is about 12 mm, and the length of the hollow tubular cooling element 22 is about 40 mm. Thus, the downstream filter segment 24 is located between the hollow tubular cooling element 22 and the downstream hollow tubular element 27. The downstream end 19 of the article 302 is defined by the downstream end of the downstream hollow tubular element 27.

The downstream hollow tubular element 27 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The downstream hollow tubular element 27 defines an inner cavity extending from the upstream end of the downstream hollow tubular element 27 to the downstream end of the downstream hollow tubular element 27. The inner cavity is substantially empty, and thus substantially unrestricted airflow is achieved along the inner cavity. The downstream hollow tubular element 27 may not substantially affect the overall RTD of the aerosol-generating article 302. The length of the downstream hollow tubular element 27 is about 5 mm. The wall thickness of the downstream hollow tubular element 27 is about 1 mm.

The aerosol-generating article 304 shown in Figure 11 is similar to the aerosol-generating article 302 shown in Figure 10, and differs in that the ventilation zone 36 is instead provided along the downstream hollow tubular element 27. The ventilation zone 36 is provided approximately 2 mm from the upstream end of the downstream hollow tubular element 27. The ventilation zone 36 includes at least one row of circumferential perforations extending through the outer peripheral wall of the downstream hollow tubular element 27 and any wrapper (not shown) defining the downstream hollow tubular element 27.

The aerosol-generating article 40 shown in Figure 12 comprises a strip of aerosol-generating substrate 12 and a downstream section 14 located downstream of the strip of aerosol-generating substrate 12. In addition, the aerosol-generating article 40 comprises an upstream section 16 located upstream of the strip of aerosol-generating substrate 12. The distal end 18 of the article is defined by the upstream end of the upstream section 16.

The downstream section 14 of the aerosol generating article 40 shown in Figure 3 includes a hollow tubular support element 28, a hollow tubular cooling element 22 and a downstream filter segment 24. The hollow tubular support element 28 is positioned immediately downstream of the strip 12 of the aerosol generating substrate. In other words, the hollow tubular support element 28 is adjacent to the downstream end of the strip 12. The hollow tubular cooling element 22 is adjacent to the downstream end of the hollow tubular support element 28, and the downstream filter segment 24 is adjacent to the downstream end of the hollow tubular cooling element 22. Therefore, the hollow tubular cooling element 22 is located between the hollow tubular support element 28 and the downstream filter segment 24. The downstream end 19 of the article 40 is defined by the downstream end of the downstream filter segment 24.

The length of the strip 12 of aerosol-generating substrate is approximately 20 mm.

The hollow tubular support element 28 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The hollow tubular support element 28 defines an inner cavity extending from the upstream end of the hollow tubular support element 28 to the downstream end of the hollow tubular support element 28. The inner cavity is substantially empty, and thus substantially unrestricted airflow is achieved along the inner cavity. The hollow tubular support element 28 may not substantially affect the overall RTD of the aerosol-generating article 40. The length of the hollow tubular support element 28 is about 8 mm. The wall thickness of the hollow tubular support element 28 is about 1.5 mm.

The hollow tubular cooling element 22 is provided in the form of a hollow cylindrical tube made of paperboard or cellulose acetate. The hollow tubular cooling segment 22 defines an inner cavity extending from the upstream end of the hollow tubular cooling element 22 to the downstream end of the hollow tubular cooling element 22. The inner cavity is substantially empty, and thus substantially unrestricted airflow is achieved along the inner cavity. The hollow tubular cooling element 22 may not substantially affect the overall RTD of the aerosol-generating article 40. The length of the hollow tubular cooling element 22 is about 8 mm. The wall thickness of the hollow tubular cooling element 22 is about 250 micrometers (µm).

The downstream filter segment 24 comprises a cylindrical rod of cellulose acetate tow. The length of the downstream filter segment 24 is approximately 12 mm.

The upstream section 16 comprises an upstream element 341 adjacent the upstream end of the strip 12. The upstream element 341 is provided in the form of a cylindrical rod of cellulose acetate tow. The length of the upstream element 341 is about 5 mm.

The aerosol-generating article 40 includes a ventilation zone 36 disposed at a location along the hollow tubular cooling element 22. The ventilation zone 36 includes at least one row of circumferential perforations extending through the outer peripheral wall of the hollow tubular cooling element 22 and any wrapper (not shown) defining the hollow tubular cooling element 22. The ventilation zone 36 is disposed approximately 2 mm from the downstream end of the hollow tubular cooling element 22.

The aerosol-generating article 40 comprises an elongated susceptor element 44 positioned within the strip 12 of aerosol-generating substrate. The susceptor element 44 is arranged substantially longitudinally within the strip 12 so as to be generally parallel to the longitudinal direction of the strip 12. Since the elongated susceptor element 44 is positioned in thermal contact with the aerosol-generating substrate, the aerosol-generating substrate is heated by the susceptor element 44 when the susceptor element 44 is inductively heated when positioned within the fluctuating electromagnetic field.

As shown in Figure 12, the susceptor element 44 is positioned in a radially central position within the strip and effectively extends along the longitudinal axis of the strip 12. The susceptor element 44 extends from the upstream end to the downstream end of the strip 12. In practice, the susceptor element 44 has substantially the same length as the strip 12 of aerosol generating substrate.

The susceptor element 44 is provided in any form described in the present disclosure and has a length substantially equal to the length of the strip 12. The upstream section 16 advantageously prevents the susceptor element 44 from being removed. Furthermore, this ensures that the consumer does not accidentally come into contact with the heated susceptor element 44 after use.

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

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

The downstream hollow tubular element 27 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The downstream hollow tubular element 27 defines an inner cavity extending from the upstream end of the downstream hollow tubular element 27 to the downstream end of the downstream hollow tubular element 27. The inner cavity is substantially empty, and thus substantially unrestricted airflow is achieved along the inner cavity. The downstream hollow tubular element 27 may not substantially affect the overall RTD of the aerosol-generating article 402. The length of the downstream hollow tubular element 27 is about 5 mm. The wall thickness of the downstream hollow tubular element 27 is about 1 mm.

The aerosol-generating article 403 shown in Figure 15 is similar to the aerosol-generating article 402 shown in Figure 14, and differs in that a ventilation zone 36 is provided along the downstream hollow tubular element 27. The ventilation zone 36 is provided approximately 2 mm from the upstream end of the downstream hollow tubular element 27. The ventilation zone 36 includes at least one row of circumferential perforations extending through the outer peripheral wall of the downstream hollow tubular element 27 and any wrapper (not shown) defining the downstream hollow tubular element 27.

Figure 16 shows an aerosol generating system 1 comprising an exemplary aerosol generating device 50 and an aerosol generating article according to any one of those shown in Figures 1 to 15 and described above.

Figure 16 shows a downstream mouth end portion of an aerosol generating device 50 where a device cavity is defined and an aerosol generating article can be received. The aerosol generating device 50 includes a housing (or body) 4 extending between a mouth end 2 and a distal end (not shown). The housing 4 includes a peripheral wall 6. The peripheral wall 6 defines a device cavity for receiving an aerosol generating article 10. The device cavity is defined by a closed distal end and an open mouth end. The mouth end of the device cavity is located at the mouth end of the aerosol generating device 1. The aerosol generating article 10 is configured to be received by the mouth end of the device cavity and is configured to be adjacent to the closed end of the device cavity.

The device airflow channel 5 is defined within the peripheral wall 6. The airflow channel 5 extends between an inlet 7 located at the mouth end of the aerosol generating device 1 and the closed end of the device cavity. Air can enter the aerosol generating substrate 12 via an orifice (not shown) provided at the closed end of the device cavity to ensure fluid communication between the airflow 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 to control such power supply to the heater. The heater is configured to controllably heat the aerosol generating article during use when the aerosol generating article is received in the device 1. The heater is preferably arranged to externally heat an aerosol generating substrate of the aerosol generating article for optimal aerosol generation. The ventilation region of the aerosol generating article is arranged to be exposed when the aerosol generating article is received in the aerosol generating device 1.

For the purpose of this specification and the appended claims, unless otherwise stated, all numbers representing amounts, quantities, percentages, etc. should be understood to be modified by the term "about" in all cases. Moreover, all ranges include disclosed maximum and minimum points, and include any intermediate ranges therein that may be specifically listed or may not be listed herein. Therefore, in this article, the number A is understood to be ± 10% of A. In this article, the number A may be considered to be included in the numerical value within the general standard error of the measurement of the property modified by the number A. In some cases used in the appended claims, the number A may deviate from the percentage listed above, provided that the amount of A deviation will not substantially affect the basic features and novel features of the invention claimed for protection. Moreover, all ranges include disclosed maximum and minimum points, and include any intermediate ranges therein that may be specifically listed or may not be listed herein.

Claims (15)

1. An aerosol-generating article comprising:

A strip of aerosol-generating substrate;

A downstream section disposed downstream of the strip of aerosol-generating substrate and extending to a downstream end of the aerosol-generating article, wherein the downstream section comprises a hollow tubular cooling element, and wherein the downstream section has a length of greater than 45 millimeters;

An upstream element disposed upstream of and abutting an upstream end of the strip of aerosol-generating substrate, wherein the upstream element has a length of at least 3 millimeters.

2. An aerosol-generating article according to claim 1, wherein the strips of aerosol-generating substrate have a length of less than 30mm.

3. An aerosol-generating article according to claim 2, wherein the aerosol-generating article has an overall length of at least 60 mm.

4. An aerosol-generating article according to any preceding claim, wherein the hollow tubular cooling element of the downstream section has a length of at least 40 mm.

5. An aerosol-generating article according to any preceding claim, wherein the hollow tubular cooling element abuts a downstream end of the strip of aerosol-generating substrate.

6. An aerosol-generating article according to any preceding claim, wherein the ratio of the length of the hollow tubular cooling element of the downstream section to the length of the strip of aerosol-generating substrate is at least 1.5.

7. An aerosol-generating article according to any preceding claim, wherein the ratio of the length of the upstream element to the length of the hollow tubular element of the downstream section is between 0.01 and 0.15.

8. An aerosol-generating article according to any preceding claim, wherein the largest outer diameter of the aerosol-generating article is less than 7 mm.

9. An aerosol-generating article according to any preceding claim, wherein the upstream element has a length of between 3 and 6 mm.

10. An aerosol-generating article according to any preceding claim, wherein the upstream element comprises a hollow tubular section having a central longitudinal cavity extending therethrough.

11. An aerosol-generating article according to claim 10, wherein the hollow tubular section of the upstream element has a wall thickness of less than 1 millimeter.

12. An aerosol-generating article according to any preceding claim, wherein the upstream element has a Resistance To Draw (RTD) of less than or equal to 10mm H ₂ O.

13. An aerosol-generating article according to any preceding claim, further comprising a ventilation zone at a location along the hollow tubular cooling element of the downstream section.

14. An aerosol-generating article according to any preceding claim, wherein the hollow tubular cooling element of the downstream section has a wall thickness of less than 0.5 mm.

15. An aerosol-generating article according to any preceding claim, wherein the downstream section further comprises a downstream filter segment disposed downstream of the hollow tubular cooling element.