CN118317708A

CN118317708A - Aerosol-generating article comprising a hollow tubular matrix element with a sealing element

Info

Publication number: CN118317708A
Application number: CN202280078966.XA
Authority: CN
Inventors: R·卡利; 张耀之
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2021-12-06
Filing date: 2022-12-05
Publication date: 2024-07-09

Abstract

An aerosol-generating article (10) (110) comprising: an aerosol-generating substrate (12) comprising a hollow tubular substrate element (40) having a peripheral wall (42) defining a longitudinal airflow channel (44) extending between an upstream end and a downstream end of the hollow tubular substrate element (40), wherein the peripheral wall (42) is formed from one or more layers of homogenized plant material; a sealing element (24) at an upstream end of the hollow tubular matrix element (40), wherein the sealing element (24) is arranged to provide a substantially airtight seal at an upstream end of the longitudinal gas flow channel (44); and a downstream section (14) disposed downstream of the aerosol-generating substrate (12).

Description

Aerosol-generating article comprising a hollow tubular matrix element with a sealing element

Technical Field

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

Background

Aerosol-generating articles in which an aerosol-generating substrate, such as a tobacco-containing substrate, is heated rather than combusted are known in the art. Generally, in such heated smoking articles, an aerosol is generated by transferring heat from a heat source to a physically separate aerosol-generating substrate or material that 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 entrained in air drawn through the aerosol-generating article. As the released compound cools, the compound condenses to form an aerosol.

A number of prior art documents disclose aerosol-generating devices for consuming aerosol-generating articles. Such devices include, for example, electrically heated aerosol-generating devices in which 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 have been proposed which comprise an internal heater blade adapted to be inserted into an aerosol-generating substrate. It is also known to use aerosol-generating articles in combination with external heating systems. For example, WO-A-2020/115151 describes the provision of one or more heating elements arranged around the periphery of an aerosol-generating article when the aerosol-generating article is received in A cavity of an aerosol-generating device. As an alternative WO-A-2015/176898 proposes an inductively heatable aerosol-generating article comprising an aerosol-generating substrate and A susceptor arranged within the aerosol-generating substrate.

In general, it may be difficult to provide efficient heating of the aerosol-generating substrate across the entire strip of the substrate. The portion of the substrate closest to the heating element will inevitably be heated most effectively, while imperfect transfer of heat through the substrate will mean that the portion of the substrate furthest from the heating element may not be heated effectively. Thus, aerosol generation from those portions of the substrate that are not effectively heated is not optimal, and in some cases, portions of the substrate may not reach sufficiently high temperatures at all during use to generate an aerosol. For example, in the case of using an external heating element to heat a strip of aerosol-generating substrate, as described above, the central portion of the strip of aerosol-generating substrate is less likely to generate as much aerosol as the outer portion of the strip, and in some cases may not generate any aerosol. In summary, aerosol generation from an aerosol-generating rod may thus be inefficient, wherein a portion of the aerosol-generating substrate may be wasted.

The aerosol-generating article is designed to provide a specific airflow pattern during use, which determines the location where air is drawn into the aerosol-generating article during use, how the air flows through the aerosol-generating article and how the air mixes with the aerosol generated by the aerosol-generating substrate. Many existing aerosol-generating articles are designed to provide a longitudinal air flow, which means that air is drawn through the article in a longitudinal direction from an upstream end to a downstream end. Aerosol-generating articles are also known which provide a transverse air flow, wherein air is drawn through the aerosol-generating substrate in a transverse or circumferential direction from the outside towards the inside of the article. In such articles, a side-to-side airflow is provided instead of a side-to-side airflow.

It has been found to be technically difficult to provide an aerosol-generating article that is capable of utilizing both longitudinal and transverse air flows during use, while still providing an article that maintains other desirable characteristics, such as acceptable Resistance To Draw (RTD) levels and required ventilation levels.

Disclosure of Invention

It is therefore desirable to provide an aerosol-generating article adapted to allow greater flexibility in the airflow that can be provided. In particular, it would be desirable if both longitudinal and transverse air flows could be used for the same article while maintaining the desired characteristics of the article. It is particularly desirable to provide an article having a relatively simple design such that it can be manufactured in a cost-effective manner and incorporated into existing product designs. It is also desirable to provide an aerosol-generating article having an aerosol-generating substrate that is adapted to provide more efficient aerosolization of the aerosol-generating substrate and reduce wastage of substrate material such as tobacco. It is also desirable to provide an article that can be easily adapted such that it can be heated in various types of heating devices, including induction heating devices and resistance heating devices.

The present disclosure relates to an aerosol-generating article. The aerosol-generating article may comprise an aerosol-generating substrate comprising a hollow tubular substrate element. The hollow tubular matrix member may have a peripheral wall defining a longitudinal gas flow channel extending between an upstream end and a downstream end of the hollow tubular matrix member. The peripheral wall may be formed from one or more layers of homogenized plant material. The aerosol-generating article may further comprise a sealing element at the upstream end of the hollow tubular matrix element. The sealing element may be arranged to provide a substantially airtight seal at the upstream end of the hollow tubular matrix element. The aerosol-generating article may further comprise a downstream section arranged downstream of the aerosol-generating substrate.

According to the present invention, there is provided: an aerosol-generating article, the aerosol-generating article comprising: an aerosol-generating substrate comprising a hollow tubular substrate element having a peripheral wall defining a longitudinal airflow channel extending between an upstream end and a downstream end of the hollow tubular substrate element, wherein the peripheral wall is formed from one or more layers of homogenized plant material; a sealing element at an upstream end of the hollow tubular matrix element, wherein the sealing element is arranged to provide a substantially airtight seal at an upstream end of the longitudinal channel; and a downstream section disposed downstream of the aerosol-generating substrate.

As used herein, the term "aerosol-generating article" refers to a heated article for generating an aerosol, wherein the article comprises an aerosol-generating substrate that is suitable and intended to be heated or combusted so as to release volatile compounds that can form an aerosol. Such articles are commonly referred to as heated non-flammable articles. When a user applies a flame to one end of the cigarette and draws air through the other end, the conventional cigarette will be lit. The localized heat provided by the flame and oxygen in the air drawn through the cigarette causes the ends of the cigarette to be lit and the resulting combustion generates inhalable smoke. In contrast, in a "heated aerosol-generating article", the aerosol is generated by heating the aerosol-generating substrate rather than by burning the aerosol-generating substrate. Heated aerosol-generating articles are known to include, for example, electrically heated aerosol-generating articles and aerosol-generating articles in which an aerosol is generated by heat transfer from a combustible fuel element or heat source to a physically separate aerosol-generating substrate.

Aerosol-generating articles suitable for use in aerosol-generating systems for supplying an aerosol-forming agent to the aerosol-generating article are also known. In this system, the aerosol-generating substrate in the aerosol-generating article contains significantly less aerosol-forming agent relative to those that carry and provide substantially all of the aerosol-forming agent used in forming an aerosol during operation.

As used herein, the term "aerosol-generating substrate" refers to a substrate capable of releasing volatile compounds that can form an aerosol upon heating. The aerosols generated by the aerosol-generating substrates of the aerosol-generating articles described herein may be visible or invisible and may comprise vapors (e.g., fine particles of a substance in a gaseous state, which is typically a liquid or solid at room temperature) as well as gases and droplets of condensed vapors.

As used herein, the term "homogenized plant material" encompasses any plant material formed from the agglomeration of plant particles. For example, a sheet or web of homogenized tobacco material for use in an aerosol-generating substrate of the invention may be formed by agglomerating particles of tobacco material obtained by comminuting, grinding or milling plant material and optionally one or more of tobacco lamina and tobacco leaf stems. The homogenized plant material may be produced by casting, extrusion, papermaking processes, or any other suitable process known in the art.

As used herein, the term "substantially airtight seal" means that the sealing element provides a seal on the upstream end of the longitudinal channel that substantially prevents air from being drawn into the longitudinal channel at the upstream end of the hollow tubular matrix element during normal use of the aerosol-generating article in the aerosol-generating device. Preferably, the sealing element provides a gas-tight seal that prevents any air from entering the longitudinal channel through the upstream end.

In the aerosol-generating article according to the invention, the upstream end of the longitudinal channel is thus covered and sealed by a sealing element provided at the upstream end of the hollow tubular matrix element. With the sealing element in place and still intact, longitudinal air flow is prevented from passing through the longitudinal air flow channel because air cannot enter the longitudinal air flow channel at the upstream end. Instead, the hollow tubular matrix element is adapted such that air is drawn from outside the hollow tubular matrix element through the one or more layers of homogenized plant material laterally through the peripheral wall and into the longitudinal air flow channels. As described in more detail below, the hollow tubular matrix element is preferably porous due to the arrangement of overlapping layers of homogenized plant material.

The provision of a transverse air flow may be particularly advantageous when the heating of the hollow tubular matrix element takes place externally, so that heat is transferred from the outside to the inside of the hollow tubular matrix element through the peripheral wall. Due to the tubular form of the matrix, which provides a relatively thin wall for air penetration, the side-to-side airflow may work particularly efficiently.

Once the sealing element is removed or pierced, an opening is provided at the upstream end of the longitudinal gas flow channel and a longitudinal gas flow is achieved between the upstream and downstream ends of the hollow tubular matrix element. A combination of longitudinal and transverse air flows is possible, wherein the air flows are partly longitudinal and partly transverse. The addition of a longitudinal air flow may advantageously improve the flow of aerosol through the hollow tubular matrix element.

The inclusion of the sealing element thus provides greater flexibility in terms of the possible airflow designs achievable with the aerosol-generating article according to the invention. There is also greater control over the airflow provided during use so that the aerosol-generating article according to the invention may be more accurately adapted to provide the desired airflow pattern during use. This may advantageously enable the aerosol-generating article to be optimised according to the particular design of the aerosol-generating device with which it is intended to be used.

Thus, the aerosol-generating article according to the invention provides a novel configuration which enables both longitudinal and transverse airflow to be provided during use, alone or in combination. The configuration as defined may be incorporated into an aerosol-generating article while still being able to achieve a desired level of ventilation and RTD.

The sealing element may advantageously be adapted such that the sealing element is automatically pierced, pierced or ruptured when the aerosol-generating article is inserted into the heating chamber of the aerosol-generating device. In some cases, the presence of the sealing element may also facilitate the correct insertion of the heating element into the article, for example, wherein the internal heating element is inserted into the hollow tubular matrix element.

Furthermore, the sealing element may advantageously prevent contamination or degradation of the interior of the hollow tubular matrix element prior to use.

As defined above, the present invention provides an aerosol-generating article having an aerosol-generating substrate in the form of a hollow tubular substrate element. The hollow tubular matrix member includes one or more layers of homogenized plant material that forms a peripheral wall of the hollow tubular matrix member. The "peripheral" wall of the hollow tubular matrix corresponds to the main wall defining the tubular structure. Preferably, the hollow tubular matrix element is constituted by the peripheral wall only. Thus, the peripheral wall contains all homogenized plant material that will generate aerosol upon heating of the aerosol-generating substrate.

The peripheral wall of the hollow tubular matrix element defines a longitudinal air flow channel, wherein the term "longitudinal" relates to the longitudinal axis of the aerosol-generating article. Preferably, the longitudinal air flow channel is empty or substantially empty, such that there is nothing in the channel that could potentially impede the flow of air and aerosol through the hollow tubular matrix element. In particular, the longitudinal air flow channel is substantially free of plant material including tobacco material.

The provision of the aerosol-generating substrate in tubular form advantageously enables the amount of plant material in the aerosol-generating substrate to be optimised so that an aerosol can be effectively generated from the aerosol-generating substrate upon heating. The tubular form also removes a central portion of homogenized plant material that may not be heated as effectively as an outer portion, particularly in an aerosol-generating device comprising an external heating device. Overall, the amount of plant material may thus be significantly reduced, and plant waste may be reduced, compared to conventional solid bars of homogenized plant material. For example, where the homogenized plant material comprises tobacco particles, it has been found that the amount of tobacco material in the hollow tubular matrix element for an aerosol-generating article according to the invention may be reduced by up to 40% as compared to the amount of tobacco material used in a matrix solid rod in a conventional aerosol-generating article, while maintaining similar delivery of the aerosol to the consumer.

By controlling parameters of the hollow tubular matrix element, such as the density and wall thickness of the peripheral wall, the amount of plant material provided in the matrix can be easily modified. In this way, it is possible to modify the hollow tubular matrix element such that it matches the heating zone of the associated aerosol-generating device. Thus, the proportion of aerosol-generating substrate that can be heated to the required temperature for aerosol generation can be maximised so that the generation of aerosol from the aerosol-generating substrate is optimised.

As described above, the hollow tubular matrix element is formed from one or more layers of homogenized plant material. Preferably, the hollow tubular matrix element is formed from a plurality of overlapping layers of homogenized plant material. Preferably, the multiple overlapping layers of homogenized plant material are directly overlying each other such that adjacent layers are in direct contact with each other without an intermediate layer. The plurality of overlapping layers of homogenized plant material may advantageously be arranged to define a plurality of voids between adjacent layers. Thus, as mentioned above, the peripheral wall generally has a porous structure that enables the lateral airflow to pass through the peripheral wall during use. As described in more detail below, the voids defined between adjacent layers of homogenized plant material may advantageously provide both lateral and longitudinal porosity such that aerosol generated upon heating the aerosol-generating substrate is effectively released into the longitudinal airflow channels and flows through the channels, mixing with external air that is drawn through the article upon consumer suction.

The multi-layer arrangement of layers additionally provides a relatively dense structure with sufficient structural rigidity to provide an aerosol-generating substrate in the aerosol-generating article without the need for any additional support, such as a carrier layer or an internal support member within the longitudinal airflow channel.

The diameter of the longitudinal airflow channel may be adapted to provide greater control over the management of airflow through the aerosol-generating article.

The hollow tubular matrix element has a relatively simple structure which can be produced in a simple and cost-effective manner using existing equipment. The hollow tubular matrix element may then be included with other components into an aerosol-generating article using known assembly methods and apparatus.

Advantageously, if desired, the hollow tubular matrix element may be directly included into the aerosol-generating article without an outer wrapper. This provides a unique appearance and texture to the outer surface of the aerosol-generating substrate.

As described above, the hollow tubular matrix element forming the aerosol-generating matrix of the aerosol-generating article according to the invention is formed from a plurality of overlapping layers of homogenized plant material. The layers overlap each other in the transverse direction to provide a multilayer structure.

Preferably, the hollow tubular matrix element comprises at least about 2 overlapping layers of homogenized plant material, more preferably at least about 3 overlapping layers of homogenized plant material.

Preferably, the hollow tubular matrix element comprises up to about 10 overlapping layers of homogenized plant material, more preferably up to about 5 overlapping layers of homogenized plant material. For example, the hollow tubular matrix element may comprise about 2 to about 10 overlapping layers of homogenized plant material, or about 3 to about 5 overlapping layers of homogenized plant material.

As mentioned above, the peripheral wall of the hollow tubular matrix element preferably has a porous structure due to the voids formed between the overlapping layers of homogenized plant material. Preferably, the peripheral wall is porous both transversely and longitudinally.

Preferably, the peripheral wall of the hollow tubular matrix member has a cross-sectional porosity of at least about 0.3, more preferably at least about 0.35 and most preferably at least about 0.4.

Preferably, the peripheral wall has a cross-sectional porosity of up to about 0.7, more preferably up to about 0.65, most preferably up to about 0.6.

For example, the cross-sectional porosity of the peripheral wall may be between about 0.3 and about 0.7, or between about 0.35 and about 0.65, or between about 0.4 and about 0.6.

As used herein, the term "porosity" refers to the fraction of void space in a gas permeable or porous body. In particular, in the context of the present invention, the term "cross-sectional porosity" refers to the fraction of void space in a cross-sectional area of the peripheral wall of the hollow tubular matrix element. The cross-sectional porosity is the area fraction of void space in the cross-sectional area of the peripheral wall. The cross-sectional area of the peripheral wall is the area of the peripheral wall in a plane perpendicular to the longitudinal axis of the hollow tubular matrix element.

Additional details regarding measuring cross-sectional porosity in porous or gas permeable bodies can be found in the international patent application WO-A-2016/023965 published under the name of the present inventors.

The cross-sectional porosity of the peripheral wall enables the aerosol to pass through the peripheral wall in a transverse direction such that it can be drawn into the longitudinal airflow channel and through the longitudinal airflow channel.

Preferably, the peripheral wall of the hollow tubular matrix member has a density of at least about 200 mg/cc, more preferably at least about 300 mg/cc, more preferably at least about 400 mg/cc, more preferably at least about 500 mg/cc, more preferably at least about 600 mg/cc, more preferably at least about 700 mg/cc, more preferably at least about 800 mg/cc.

Preferably, the peripheral wall of the hollow tubular matrix member has a density of less than about 1 gram per cubic centimeter.

In the context of the present invention, "density" refers to the overall density of the peripheral walls comprising overlapping layers, rather than the density of the individual layers. The relatively high density of the peripheral wall maximizes the amount of plant material that can be provided for a given length of aerosol-generating substrate, so that the amount of aerosol generated by the hollow tubular substrate element can be maximized.

Preferably, the peripheral wall provides a hollow tubular matrix of at least about 150 milligrams of homogenized plant material per centimeter length, more preferably at least about 200 milligrams of homogenized plant material per centimeter length, more preferably at least about 300 milligrams of homogenized plant material per centimeter length, more preferably at least about 400 milligrams of homogenized plant material per centimeter length, more preferably at least about 500 milligrams of homogenized plant material per centimeter length, more preferably at least about 600 milligrams of homogenized plant material per centimeter length, more preferably at least about 700 milligrams of homogenized plant material per centimeter length, more preferably at least about 800 milligrams of homogenized plant material per centimeter length. This is based on measurements made at 22.5 degrees celsius at 60% humidity.

Preferably, the hollow tubular matrix member has a longitudinal tensile strength of between 11 kilonewtons per meter and 14 kilonewtons per meter as measured according to TAPPI test method T494om-01 2006.

Preferably, the hollow tubular matrix element has an axial compressive strength of between 7MPa and 9MPa measured according to the test method described in ASTM D695-15 (2018).

Preferably, the radial compressive strength of the hollow tubular matrix element measured according to the test method described in ASTM D2412-11 (2018) is between 7MPa and 9 MPa.

Preferably, the hollow tubular matrix element has a length of at least about 10 millimeters, more preferably at least about 12 millimeters, more preferably at least about 15 millimeters.

Preferably, the hollow tubular matrix element has a length of up to about 40 mm, more preferably up to about 37 mm, more preferably up to about 35 mm.

For example, the hollow tubular matrix element can have a length of between about 10 millimeters and about 40 millimeters, or between about 12 millimeters and about 37 millimeters, or between about 15 millimeters and about 35 millimeters.

As discussed above, the length of the hollow tubular matrix element may advantageously match the longitudinal dimension of a heating element in a corresponding aerosol-generating device to be used for heating an aerosol-generating article. In this way, as much of the aerosol-generating substrate as possible may be heated during use in order to optimise the amount of aerosol that can be generated and reduce the amount of plant material waste, such as tobacco waste.

Preferably, the ratio of the length of the hollow tubular matrix element to the overall length of the aerosol-generating article is at least about 0.15. More preferably, the ratio of the length of the hollow tubular matrix element to the overall length of the aerosol-generating article is at least about 0.25. More preferably, the ratio of the length of the hollow tubular matrix element to the overall length of the aerosol-generating article is at least about 0.4.

Preferably, the ratio of the length of the hollow tubular matrix element to the overall length of the aerosol-generating article is up to about 0.6. More preferably, the ratio of the length of the hollow tubular matrix element to the overall length of the aerosol-generating article is up to about 0.55. More preferably, the ratio of the length of the hollow tubular matrix element to the overall length of the aerosol-generating article is up to about 0.5.

For example, the ratio of the length of the hollow tubular matrix element to the overall length of the aerosol-generating article may be between about 0.15 and about 0.6, more preferably between about 0.25 and about 0.55, more preferably between about 0.4 and about 0.5.

Preferably, the hollow tubular matrix member has an outer diameter of at least about 4 millimeters, more preferably at least about 4.25 millimeters, and more preferably at least about 4.5 millimeters.

Preferably, the hollow tubular matrix member has an outer diameter of up to about 9 millimeters, more preferably up to about 8 millimeters, and more preferably up to about 7.5 millimeters.

For example, the hollow tubular matrix element can have an outer diameter of between about 4 millimeters and about 9 millimeters, or between about 4.25 millimeters and about 8 millimeters, or between about 4.5 millimeters and about 7.5 millimeters.

Preferably, the outer diameter of the hollow tubular matrix element is substantially the same as the outer diameter of the aerosol-generating article.

As described above, the hollow tubular matrix element provides a longitudinal airflow channel defined by the peripheral wall. The longitudinal gas flow channel extends between the upstream and downstream ends of the hollow tubular matrix element and is preferably open at the downstream end. The longitudinal air flow channels provide a primary passageway for air and aerosol to flow through the article.

Preferably, the hollow tubular matrix element provides an unrestricted flow channel. This means that the hollow tubular section provides a negligible level of resistance to suction (RTD). The term "negligible level RTD" is used to describe an RTD of less than 1mm H ₂ O per 10 mm length of hollow tubular element, preferably less than 0.4mm H ₂ O per 10 mm length of hollow tubular element, more preferably less than 0.1mm H ₂ O per 10 mm length of hollow tubular element.

Preferably, the longitudinal air flow channel has a diameter of at least 3mm. This corresponds to the inner diameter of the hollow tubular matrix member. Preferably, the longitudinal air flow channels have a diameter of at least about 3.25 millimeters, more preferably at least about 3.5 millimeters.

Preferably, the longitudinal air flow channels have a diameter of up to about 7 millimeters, more preferably up to about 6 millimeters, more preferably up to about 5.5 millimeters.

For example, the longitudinal air flow channels may have a diameter of between about 3 millimeters and about 7 millimeters, or between about 3.25 millimeters and about 6 millimeters, or between about 3.5 millimeters and about 5.5 millimeters.

Providing an airflow channel having a minimum diameter of 3 mm enables the volume of the channel to be sufficiently large to provide a desired level of airflow while also maintaining a sufficient wall thickness. This is necessary so that a sufficient amount of plant material is provided within the hollow tubular matrix element, and so that the hollow tubular matrix element has a sufficiently high stiffness so that it can be self-supporting.

The longitudinal gas flow channels may have a constant diameter along the length of the hollow tubular matrix element. However, the diameter of the longitudinal gas flow channels may vary along the length of the hollow tubular matrix member.

Preferably, the longitudinal air flow channel has a substantially circular cross section. Alternatively, the longitudinal air flow channel may have a substantially oval cross section.

Preferably, the ratio of the inner diameter to the outer diameter of the hollow tubular matrix member is at least about 0.4, more preferably at least about 0.45 and more preferably at least about 0.5.

Preferably, the outer diameter of the hollow tubular matrix member and the diameter of the longitudinal gas flow channels are adapted to provide a desired wall thickness to the peripheral wall. Preferably, the peripheral wall has a wall thickness of at least about 1 millimeter, more preferably at least about 1.25 millimeter and more preferably at least about 1.5 millimeter.

Preferably, the peripheral wall has a wall thickness of up to about 2.25 mm, more preferably up to about 2 mm, more preferably up to about 1.8 mm.

For example, the peripheral wall may have a thickness of between 1 millimeter and about 2.25 millimeters, or between about 1.25 millimeters and about 2 millimeters, or between about 1.5 millimeters and about 1.8 millimeters.

The overlapping layers of homogenized plant material may be arranged in any suitable manner to provide the desired wall thickness and porosity to the peripheral wall. Each layer of homogenized plant material will typically extend at least once around the hollow tubular matrix element, and preferably each layer of homogenized plant material extends multiple times around the hollow tubular matrix element to build up the structure of the peripheral wall.

Preferably, the multilayer homogenized plant material is spirally wound around the longitudinal axis of the hollow tubular matrix element. This provides a spirally wound structure similar to the layered structure of a conventional paper straw. Hollow tubular matrix elements comprising a spiral arrangement of layers for use in the present invention can be manufactured using existing straw manufacturing equipment, such as Hauni STRAW MAKER (HSM) from Hauni Maschinenbau GmbH.

The use of a spiral wound structure provides the hollow tubular matrix element with optimal structural strength with increased mechanical strength in all directions compared to a similar structure with a simple longitudinal wrap. In addition, the spiral winding arrangement enables a higher density of homogenized plant material in the peripheral wall. The manufacturing method for producing the helical arrangement of layers additionally provides for greater control of the dimensions of the hollow tubular matrix element such that variations in the outer and inner diameters are minimized. This provides greater consistency between products.

Alternatively, the hollow tubular matrix element may comprise an adhesive for sealing adjacent layers to each other. Suitable adhesives are known to those skilled in the art. Preferably, the adhesive is a water-based adhesive, such as a water-based starch adhesive or a polyvinyl alcohol (PVOH) adhesive.

Preferably, the peripheral wall of the hollow tubular matrix member formed from one or more layers of homogenized plant material is at least partially exposed on the outer surface of the hollow tubular matrix member. Thus, the hollow tubular matrix element is preferably not wrapped along at least a portion of its length. The outer surface of the peripheral wall should provide an acceptable surface to form the exterior of the aerosol-generating article, and the layered structure may provide a unique appearance and texture.

Alternatively, the hollow tubular matrix element may be overwrapped with at least one wrapper. For example, the hollow tubular matrix element may be overwrapped with a conventional paper wrapper. The hollow tubular matrix member may be overwrapped with a tobacco-containing wrapper, such as a tobacco paper wrapper.

The hollow tubular matrix element is formed from a multilayer homogenized plant material, preferably in sheet form. As used herein with reference to the present invention, the term "sheet" describes a layered element having a width and length substantially greater than its thickness.

The sheets may each individually have a thickness of between 100 and 600 microns, preferably between 150 and 300 microns, and most preferably between 200 and 250 microns.

Preferably, the homogenized plant material is homogenized tobacco material. The homogenized tobacco material comprises tobacco particles. The sheet of homogenized tobacco material used in the present invention may have a tobacco content of at least about 40 weight percent on a dry weight basis, more preferably at least about 50 weight percent on a dry weight basis, more preferably at least about 70 weight percent on a dry weight basis, and most preferably at least about 90 weight percent on a dry weight basis.

With reference to the present invention, the term "tobacco particles" describes particles of any plant member of the genus nicotiana. The term "tobacco particles" includes ground or crushed tobacco lamina, ground or crushed tobacco leaf stem, tobacco dust, tobacco fines and other particulate tobacco by-products formed during the handling, manipulation and transportation of tobacco. In a preferred embodiment, the tobacco particles are substantially entirely derived from tobacco lamina. In contrast, the isolated nicotine and nicotine salts are tobacco-derived compounds, but are not considered tobacco particles for the purposes of the present invention and are not included in the percentage of particulate plant material.

Preferably, the homogenized plant material comprises one or more aerosol formers. Upon volatilization, the aerosol-forming agent can deliver other vaporized compounds such as nicotine and flavoring agents in the aerosol that are released from the aerosol-generating substrate upon heating. Suitable aerosol formers included in homogenized plant material are known in the art and include, but are not limited to: polyols such as triethylene glycol, propylene glycol, 1, 3-butanediol 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 about 5 wt.% and about 30 wt.% on a dry weight basis, for example between about 10 wt.% and about 25 wt.% on a dry weight basis, or between about 15 wt.% and about 20 wt.% on a dry weight basis. The aerosol former may act as a humectant in the homogenized plant material.

The two or more overlapping layers of homogenized plant material forming the peripheral wall of the hollow tubular matrix element may all be formed from the same homogenized plant material. Alternatively, the peripheral wall comprises one or more layers of a first homogenized plant material and one or more layers of a second homogenized plant material different from the first homogenized plant material. Thus, the peripheral wall is formed by a combination of at least two different homogenized plant materials. The first homogenized plant material and the second homogenized plant material may differ from each other in composition. For example, the first homogenized plant material and the second homogenized plant material may have different tobacco content than each other, or different aerosol former content, or both. Alternatively or additionally, the first homogenized plant material and the second homogenized plant material have been provided with different levels of flavoring in order to provide a flavor profile. Alternatively or additionally, the first homogenized plant material and the second homogenized plant material may differ from each other in one or more physical parameters, including, but not limited to, density, porosity, or thickness.

The use of different homogenized plant material within a hollow tubular matrix element provides greater flexibility in delivering aerosols upon heating. For example, the composition of the first homogenized plant material and the second homogenized plant material may be adapted to provide delivery of the aerosol at different times or at different rates. The use of different homogenized plant materials may also provide improved stability, for example, by avoiding combinations of potentially incompatible components.

Preferably, in embodiments in which the aerosol-generating substrate comprises homogenized tobacco material, the multi-layer homogenized tobacco material comprises one or more casting She Piancai.

Preferably, the cast leaf has a porosity at 25 degrees celsius of between about 20% and about 60%, more preferably between about 30% and about 50%, more preferably between about 35% and about 45%.

Alternatively or in addition to one or more casting She Piancai, the multi-layer homogenized tobacco material may comprise one or more layers of cigarillo paper.

Preferably, the cigarillo paper has a porosity of between about 30% and about 80%, more preferably between about 40% and about 70%, more preferably between about 50% and about 60% at 25 degrees celsius.

The peripheral wall may be formed from alternating layers of cast leaf and cigarillo paper.

The hollow tubular substrate element of the aerosol-generating article according to the invention preferably comprises one or more susceptor elements positioned in contact with the peripheral wall for inductively heating homogenized plant material during use.

As used herein, the term "susceptor element" refers to an element comprising a material capable of converting electromagnetic energy into heat. When the susceptor element is in an alternating electromagnetic field, the susceptor is heated. Heating of the susceptor element may be a 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 an electric 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 kiloamp per meter and 5 kiloamps per meter (kA m), preferably between 2kA/m and 3kA/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 1MHz and 30MHz, for example between 1MHz and 10MHz, for example between 5MHz and 7 MHz.

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

The susceptor element may comprise a non-metallic core on which a metal layer is provided. For example, the susceptor element may comprise a metal track formed on an outer surface of a ceramic core or substrate.

Preferably, the hollow tubular matrix element comprises one or more susceptor elements on the surface of the peripheral wall. The hollow tubular matrix element may comprise one or more susceptor elements on the inner surface of the peripheral wall within the longitudinal airflow channel. Alternatively or additionally, the hollow tubular matrix element may comprise one or more susceptor elements on the outer surface of the peripheral wall.

Preferably, the hollow tubular matrix element comprises a tubular susceptor element provided on at least one surface of the peripheral wall. The tubular susceptor element may be arranged on an inner surface of the peripheral wall for internally heating the hollow tubular substrate element. Alternatively, the tubular susceptor element may be arranged on an outer surface of the hollow tubular substrate element for externally heating the hollow tubular substrate element.

The use of tubular susceptor elements advantageously optimizes the heating of the homogenized plant material within the peripheral wall, since the susceptor elements are in contact with the relatively large surface area of the homogenized plant material. Due to the tubular form of the hollow tubular substrate element, the thickness of the substrate is relatively low, so that heat can be efficiently transferred through the peripheral wall from the side where the tubular susceptor element is located.

As defined above, the aerosol-generating article of the invention further comprises a sealing element provided at the upstream end of the hollow tubular matrix element to provide an airtight seal, which prevents air from being drawn into the upstream end of the longitudinal air flow channel during use. Thus, the sealing element covers and seals the opening of the longitudinal air flow channel at the upstream end.

The sealing element may be formed of any suitable material that is attachable to the hollow tubular substrate and substantially impermeable to air such that an airtight seal may be provided. The sealing element may be adapted such that it is removable by a consumer prior to use.

Preferably, the sealing element comprises a membrane layer attached to the peripheral wall at the upstream end of the hollow tubular matrix element. Preferably, the film layer is pierceable. This means that the film layer can be pierced or pierced by means of a heating element, susceptor core or other piercing element arranged in the heating chamber of the aerosol-generating device. Preferably, such penetration of the film layer occurs when the aerosol-generating article is inserted into the heating chamber prior to use.

Preferably, the film layer is formed from a laminate comprising a plurality of overlapping layers. The film layer may include one or more polymer layers. Suitable polymers include, but are not limited to, polyethylene terephthalate (PET), low and high density polyethylene (LDPE and HDPE, respectively), polypropylene (PP), polyvinyl chloride (PVC), polyamides, polyolefins, polystyrene, ethylene vinyl alcohol copolymers, and combinations thereof. Alternatively or additionally, the film layer may comprise one or more metal layers, such as one or more aluminum layers.

The membrane layer may be heat sealed to the peripheral wall of the hollow tubular matrix member. Alternatively, the membrane layer may be attached to the peripheral wall of the hollow tubular matrix element by means of a suitable adhesive, as described below.

In an alternative embodiment, the sealing element comprises a paper wrapper. The paper wrapper may be folded over the upstream end of the hollow tubular matrix member. The paper wrapper may be formed from any paper material used to provide a rod wrapper or tipping wrapper for a conventional aerosol-generating article. Preferably, to ensure that an airtight seal is provided, the paper wrapper is coated or laminated with an impermeable coating, such as a wax layer. Suitable coating materials are known to the skilled person.

Preferably, the sealing element is attached to the upstream end of the hollow tubular matrix element by means of an adhesive layer. Preferably, the adhesive layer is arranged between the sealing element and the area of the circumferential wall of the hollow tubular matrix element covered by the sealing element.

Suitable binders are known to the skilled person and include most food grade binders, such as polysaccharide binders.

The sealing element may be provided only on the upstream face of the hollow tubular matrix element. In such embodiments, the sealing element would be attached to the upstream face or edge of the peripheral wall. Alternatively, the sealing element may extend from the upstream end at least partially along the outer surface of the peripheral wall of the hollow tubular matrix element. This may facilitate sealing of the sealing element with the peripheral wall, as the contact area between the sealing element and the peripheral wall increases. For example, the sealing element may extend from the upstream end along the outer surface of the peripheral wall for at least 1mm, more preferably at least 2 mm, more preferably at least 3 mm.

In certain embodiments, as described above, the aerosol-generating article according to the invention further comprises a securing strap extending circumferentially around the hollow tubular matrix element and overlying a portion of the sealing element extending downstream from the upstream end of the hollow tubular matrix element. Preferably, the securing strap is attached to the outer surface of the hollow tubular matrix member. Preferably, the securing strap is a paper strap.

Providing a securing strap overlying the sealing element helps to hold the sealing element in place on the hollow tubular matrix member. It may also provide a more consistent appearance on the exterior of the hollow tubular matrix element and a more desirable surface texture for the consumer. Preferably, an adhesive is used to attach the securing strap to the outer surface of the hollow tubular matrix member.

Preferably, the fixation strap has a length of at least 2 millimeters, more preferably at least 3 millimeters and more preferably at least 4 millimeters.

As defined above, in the aerosol-generating article of the invention, the aerosol-generating substrate formed from the hollow tubular substrate element is combined with a downstream section located downstream of the aerosol-generating substrate. Preferably, the downstream section is located immediately downstream of the aerosol-generating substrate. Preferably, the downstream section of the aerosol-generating article extends between the aerosol-generating substrate and the downstream end of the aerosol-generating article. The downstream section may include one or more elements, each of which will be described in more detail within this disclosure.

Preferably, the downstream section comprises at least one hollow tubular element. The hollow tubular element may be arranged immediately downstream of the aerosol-generating substrate. In other words, the hollow tubular element may abut the downstream end of the aerosol-generating substrate. This arrangement optimizes the flow of aerosol from the longitudinal airflow channel of the hollow tubular substrate element into the downstream section and through the aerosol-generating article.

Preferably, the downstream section of the aerosol-generating article comprises a single hollow tubular element. In other words, the downstream section of the aerosol-generating article may comprise only one hollow tubular element.

As used throughout this disclosure, "hollow tubular element" refers to a generally elongated element that defines a lumen or airflow path along its longitudinal axis. In particular, the term "tubular" will be used hereinafter to refer to a tubular element having a substantially cylindrical section and defining at least one air flow conduit establishing uninterrupted fluid communication between an upstream end of the tubular element and a downstream end of the tubular element. However, it will be appreciated that alternative geometries (e.g., alternative cross-sectional shapes) of the tubular segments are possible. The hollow tubular element may be a single discrete element of the aerosol-generating article having a defined length and thickness.

In the context of the present invention, the hollow tubular element of the downstream section provides an unrestricted flow channel through the airflow passage. This means that the hollow tubular element provides a negligible level of resistance to suction (RTD) as defined above. Thus, the air flow path should be free of any components that obstruct the flow of air in the longitudinal direction. Preferably, the airflow path is substantially empty.

The hollow tubular element of the downstream section provides a cavity downstream of the aerosol-generating substrate, which enhances cooling and nucleation of aerosol particles generated by the aerosol-generating substrate. Thus, the hollow tubular element of the downstream section serves as an aerosol-cooling element.

The hollow tubular member may have a length of at least about 12 millimeters. The hollow tubular member may have a length of at least about 15 millimeters. The hollow tubular member may have a length of at least about 20 millimeters.

The hollow tubular element of the downstream section may have a length of less than or equal to about 50 millimeters. The hollow tubular member may have a length of less than or equal to about 45 millimeters. The hollow tubular member may have a length of less than or equal to about 40 millimeters.

For example, the hollow tubular element of the downstream section may have a length between about 12 millimeters and 50 millimeters. The hollow tubular member may have a length of between about 15 mm and 45 mm. The hollow tubular member may have a length of between about 20mm and 40 mm. The hollow tubular member may be about 30 millimeters in length.

A relatively long hollow tubular element is provided within the downstream section of the aerosol-generating article and defines a relatively long lumen. Providing a relatively long cavity maximizes the nucleation benefits described above, thereby improving aerosol formation and cooling.

The ratio between the length of the hollow tubular matrix element and the length of the hollow tubular element of the downstream section may be less than or equal to about 1.25. Preferably, the ratio between the length of the hollow tubular matrix element and the length of the hollow tubular element of the downstream section may be less than or equal to about 1. More preferably, the ratio between the length of the hollow tubular matrix element and the length of the hollow tubular element of the downstream section may be less than or equal to about 0.75.

The ratio between the length of the hollow tubular matrix member and the length of the hollow tubular member of the downstream section may be at least about 0.25. Preferably, the ratio between the length of the hollow tubular matrix element and the length of the hollow tubular element of the downstream section may be at least about 0.30. More preferably, the ratio between the length of the hollow tubular matrix member and the length of the hollow tubular member of the downstream section may be at least about 0.40.

For example, the ratio between the length of the hollow tubular matrix element and the length of the hollow tubular element of the downstream section may be between about 0.25 and about 1.25, or between about 0.3 and about 1, or between about 0.4 and about 0.75.

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

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

For example, the ratio between the length of the hollow tubular element of the downstream section and the total length of the downstream section may be between about 0.35 and about 1, or between about 0.45 and about 0.9, or between about 0.5 and about 0.85.

The ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be less than or equal to about 0.80. Preferably, the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be less than or equal to about 0.70. More preferably, the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be less than or equal to about 0.60.

The ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be at least about 0.25. Preferably, the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be at least about 0.30. More preferably, the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be at least about 0.40.

For example, the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be between about 0.25 and about 0.8, or between about 0.3 and about 0.7, or between about 0.4 and about 0.6.

The hollow tubular element of the downstream section may have a wall thickness of at least about 100 microns. The hollow tubular element of the downstream section may have a wall thickness of at least about 150 microns. The hollow tubular element of the downstream section may have a wall thickness of at least about 200 microns, preferably at least about 250 microns, and even more preferably at least about 500 microns (or 0.5 mm).

The wall thickness of the hollow tubular element of the downstream section may be less than or equal to about 2 millimeters, preferably less than or equal to about 1.5 millimeters, and even more preferably less than or equal to about 1.25mm. The hollow tubular member of the downstream section may have a wall thickness of less than or equal to about 1 millimeter. The hollow tubular member of the downstream section may have a wall thickness of less than or equal to about 500 microns.

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

Keeping the wall thickness of the hollow tubular section of the downstream section relatively low ensures that the overall internal volume of the hollow tubular element (which allows the aerosol to begin the nucleation process once the aerosol components leave the aerosol-generating substrate) and that the cross-sectional surface area of the hollow tubular element is effectively maximized, while ensuring that the hollow tubular element has the necessary structural strength to prevent collapse of the aerosol-generating article and to provide some support for the strips of aerosol-generating substrate, and that the RTD of the hollow tubular element is minimized. A larger value of the cross-sectional surface area of the lumen of the hollow tubular element is understood to be associated with a reduced velocity of the aerosol-generating stream travelling along the aerosol-generating article, which reduced velocity is also expected to facilitate aerosol nucleation. Furthermore, it appears that by using hollow tubular elements having a relatively low thickness, the ventilation air can be substantially prevented from diffusing before it comes into contact and mixes with the aerosol flow, which is also understood to further facilitate nucleation. In practice, by providing a more controlled localized cooling of the volatile material flow, the effect of cooling on the formation of new aerosol particles can be enhanced.

Preferably, the hollow tubular element of the downstream section has an outer diameter substantially equal to the outer diameter of the aerosol-generating substrate and the outer diameter of the aerosol-generating article.

The hollow tubular element may have an outer diameter of between about 5mm and about 12 mm, for example between about 5mm and about 10 mm or between about 6mm and about 8 mm. Preferably, the hollow tubular element has an outer diameter of 7.2 mm +/-10%.

The hollow tubular element of the downstream section may have a constant inner diameter along the length of the hollow tubular element. However, the inner diameter of the hollow tubular element may vary along the length of the hollow tubular element.

The hollow tubular element of the downstream section may have an inner diameter of at least about 2 millimeters. For example, the hollow tubular member can have an inner diameter of at least about 2.5 millimeters, at least about 3 millimeters, or at least about 3.5 millimeters. Providing a hollow tubular element having an inner diameter as described above may advantageously provide the hollow tubular element with sufficient rigidity and strength.

The hollow tubular element of the downstream section may have an inner diameter of no more than about 10 millimeters. For example, the hollow tubular element may have an inner diameter of no more than about 9 millimeters, no more than about 8 millimeters, or no more than about 7.5 millimeters. Providing a hollow tubular element having an inner diameter as described above may advantageously reduce the suction resistance of the hollow tubular section.

For example, the hollow tubular element of the downstream section may have an inner diameter of between about 2 millimeters and about 10 millimeters, between about 2.5 millimeters and about 9 millimeters, between about 3 millimeters and about 8 millimeters, or between about 3.5 millimeters and about 7.5 millimeters.

The ratio of the inner diameter of the hollow tubular matrix member to the inner diameter of the hollow tubular member of the downstream section is preferably between about 0.8 and about 1.2, more preferably between about 0.9 and about 1.1, most preferably about 1.

It is particularly preferred that the inner diameter of the hollow tubular matrix member is substantially equal to the inner diameter of the hollow tubular member of the downstream section.

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

Preferably, the hollow tubular element may comprise cardboard. The hollow tubular element may be a cardboard tube. The hollow tubular element may be formed from cardboard. Advantageously, the cardboard is a cost-effective material that provides a balance between being deformable so as to provide ease of insertion of the article into the aerosol-generating device and being sufficiently rigid to provide proper 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 section may be a paper tube. The hollow tubular section may be a tube formed from spirally wound paper. The hollow tubular section may be formed from a plurality of paper layers. The paper may have a basis weight of at least about 50 grams per square meter, at least about 60 grams per square meter, at least about 70 grams per square meter, or at least about 90 grams per square meter.

The hollow tubular section of the downstream section may comprise a polymeric material. For example, the hollow tubular section may comprise a polymer membrane. The polymer film may comprise a cellulosic film. The hollow tubular section may comprise low density polyethylene (HDPE) or Polyhydroxyalkanoate (PHA) fibers. The hollow tube may comprise cellulose acetate tow.

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

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

Thus, the ventilation chamber is arranged downstream of the strip of aerosol-generating substrate. This provides particularly efficient cooling of the aerosol and promotes enhanced nucleation of aerosol particles.

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

The downstream section may further comprise a mouthpiece element. The mouthpiece element may be located at the downstream end of the aerosol-generating article. Preferably, the mouthpiece element is located downstream of the hollow tubular element of the downstream section, which is described hereinabove. The mouthpiece element may extend between the hollow tubular element of the downstream section and the downstream end of the aerosol-generating article.

Providing a mouthpiece element at the downstream end of an aerosol-generating article according to the invention provides an attractive appearance and mouthfeel for the consumer.

The mouthpiece element may comprise at least one mouthpiece filter segment formed from fibrous filter material. The parameters or characteristics described in relation to the mouthpiece element as a whole are equally applicable to the mouthpiece filter segment of the mouthpiece element.

The fibrous filter material may be used to filter aerosols generated by the aerosol-generating substrate. Suitable fibrous filter materials will be known to the skilled person. Particularly preferably, the at least one mouthpiece filter segment comprises a cellulose acetate filter segment formed from cellulose acetate tow.

The mouthpiece element may be constituted by a single mouthpiece filter segment. The mouthpiece element may comprise two or more mouthpiece filter segments axially aligned with each other in abutting end-to-end relationship.

The downstream section may comprise an oral cavity at the downstream end of the mouthpiece element downstream as described above. The mouth end cavity may be defined by another hollow tubular element disposed at the downstream end of the mouthpiece. The mouth end cavity may be defined by an outer wrapper of the aerosol-generating article, wherein the outer wrapper extends from (or through) the mouthpiece element in the downstream direction.

The mouthpiece element may optionally include a flavour, which may be provided in any suitable form. For example, the mouthpiece element may comprise one or more capsules, beads or granules of flavour, or one or more filaments or threads carrying flavour.

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

Preferably, the mouthpiece element is defined by a rod wrapper. Preferably, the mouthpiece element is non-ventilated such that air does not enter the aerosol-generating article along the mouthpiece element.

Preferably, the mouthpiece element has an outer diameter substantially equal to the outer diameter of the aerosol-generating article. The diameter of the mouthpiece element (or mouthpiece filter segment) may be substantially the same as the outer diameter of the hollow tubular element. As mentioned in this disclosure, the outer diameter of the hollow tubular element may be about 7.2mm±10%.

The mouthpiece element may be between about 5mm and about 10mm in diameter. The mouthpiece element may be between about 6mm and about 8mm in diameter. The mouthpiece element may be between about 7mm and about 8mm in diameter. The diameter of the mouthpiece element may be about 7.2mm±10%. The diameter of the mouthpiece element may be about 7.25mm±10%.

The Resistance To Draw (RTD) of a component or aerosol-generating article is measured according to ISO6565-2015 unless otherwise specified. RTD refers to the pressure required to force air through the entire length of the component. The term "pressure drop" or "pumping resistance (DRAW RESISTANCE)" of a component or article may also refer to "pumping resistance (RESISTANCE TO DRAW)". Such terms generally refer to measurements according to ISO6565-2015 typically performed in a test at a volumetric flow rate of about 17.5 milliliters per second at the output or downstream end of the measurement component at a temperature of about 22 degrees celsius, a pressure of about 101kPa (about 760 torr), and a relative humidity of about 60%.

The downstream section may have a Resistance To Draw (RTD) of at least about 0mm H ₂ O. The RTD of the downstream segment may be at least about 3mm H ₂ O. The RTD of the downstream segment may be at least about 6mm H ₂ O.

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

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

The Resistance To Draw (RTD) characteristics of the downstream segment may be attributed entirely or primarily to the RTD characteristics of the mouthpiece element of the downstream segment. In other words, the RTD of the mouthpiece element of the downstream segment may fully define the RTD of the downstream segment.

The mouthpiece element may have a Resistance To Draw (RTD) of at least about 0mm H ₂ O. The RTD of the mouthpiece element may be at least about 3mm H ₂ O. The RTD of the mouthpiece element may be at least about 6mm H ₂ O.

The RTD of the mouthpiece element may be no greater than about 12mm H ₂ O. The RTD of the mouthpiece element may be no greater than about 11mm H ₂ O. The RTD of the mouthpiece element may be no greater than about 10mm H ₂ O.

The mouthpiece element may have a resistance to draw greater than or equal to about 0mm H ₂ O and less than about 12mm H ₂ O. Preferably, the mouthpiece element may have a resistance to draw greater than or equal to about 3mm H ₂ O and less than about 12mm H ₂ O. The mouthpiece element may have a resistance to draw greater than or equal to about 0mm H ₂ O and less than about 11mm H ₂ O. Even more preferably, the mouthpiece element may have a resistance to draw greater than or equal to about 3mm H ₂ O and less than about 11mm H ₂ O. Even more preferably, the mouthpiece element may have a resistance to draw greater than or equal to about 6mm H ₂ O and less than about 10mm H ₂ O. Preferably, the mouthpiece element may have a resistance to draw of about 8mm H ₂ O.

As described above, the mouthpiece element or mouthpiece filter segment may be formed from a fibrous material. The mouthpiece element may be formed from a porous material. The mouthpiece element may be formed from a biodegradable material. The mouthpiece element may be formed from a cellulosic material such as cellulose acetate. For example, the mouthpiece element may be formed from a bundle of cellulose acetate of between about 10 and about 15 denier per filament. For example, the mouthpiece element is formed from a relatively low density cellulose acetate tow, such as a cellulose acetate tow comprising fibers of about 12 denier per filament.

The mouthpiece element may be a solid rod of fibrous filter material, such as a solid rod of cellulose acetate tow.

The mouthpiece element may be formed from a polylactic acid based material. The mouthpiece element may be formed from a bio-plastics material, preferably a starch-based bio-plastics material. The mouthpiece element may be made by injection moulding or by extrusion. Bio-plastic based materials are advantageous because they can provide a mouthpiece element structure that is simple and inexpensive to manufacture, has a specific and complex cross-sectional profile that can include a plurality of relatively large air flow channels extending through the mouthpiece element material that provide suitable RTD characteristics.

The mouthpiece element may be formed from a sheet of suitable material that has been rolled, pleated, gathered, woven or folded into an element defining a plurality of longitudinally extending channels. Sheets of such suitable materials 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 mouthpiece elements may show the channels as being randomly oriented.

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

The length of the mouthpiece element may be at least about 1.5 mm. The length of the mouthpiece element may be at least about 2 mm. The length of the mouthpiece element may be equal to or less than about 7 millimeters. The length of the mouthpiece element may be equal to or less than about 4 millimeters. For example, the length of the mouthpiece element may be between about 1.5 millimeters and about 7 millimeters. The length of the mouthpiece element may be between about 2mm and about 4 mm.

The ratio between the length of the mouthpiece element and the length of the downstream section may be less than or equal to about 0.35. Preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be less than or equal to about 0.30. More preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be less than or equal to about 0.25.

The ratio between the length of the mouthpiece element and the length of the downstream section may be at least about 0.03. Preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be at least about 0.05. More preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be at least about 0.1.

For example, the ratio between the length of the mouthpiece element and the length of the downstream section is about 0.03 to about 0.35, preferably about 0.05 to about 0.30, more preferably about 0.1 to about 0.25.

The ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be less than or equal to about 0.20. Preferably, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be less than or equal to about 0.15. More preferably, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be less than or equal to about 0.1.

The ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be at least about 0.01. Preferably, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be at least about 0.02. More preferably, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be at least about 0.05.

For example, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article is from about 0.01 to about 0.2, preferably from about 0.02 to about 0.15, more preferably from about 0.05 to about 0.1.

In embodiments in which the downstream section comprises a hollow tubular element and a mouthpiece element, the ratio of the length of the hollow tubular element to the length of the mouthpiece element may be at least about 1.5. In other words, the length of the hollow tubular element may be equal to about 150% of the length of the mouthpiece. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be at least about 5. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be at least about 7.5.

The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be equal to or less than about 20. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be equal to or less than about 15. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be equal to or less than about 12.5.

For example, the ratio of the length of the hollow tubular element to the length of the mouthpiece element may be between about 1.5 and about 20, or between about 5 and about 15, or between about 7.5 and about 10.

The overall length of the downstream section is preferably at least about 15 millimeters, more preferably at least about 20 millimeters, and more preferably at least about 25 millimeters.

The overall length of the downstream section is preferably less than about 50 millimeters, more preferably less than about 45 millimeters, and more preferably less than about 40 millimeters.

For example, the downstream section may have an overall length of between about 20 millimeters and about 50 millimeters, more preferably between about 25 millimeters and about 45 millimeters, more preferably between about 30 millimeters and about 40 millimeters.

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

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

Preferably, the overall length of the aerosol-generating article according to the invention is at least about 35 mm. More preferably, the overall length of the aerosol-generating article according to the invention is at least about 40 mm. Even more preferably, the overall length of the aerosol-generating article according to the invention is at least about 45 mm. Even more preferably, the overall length of the aerosol-generating article according to the invention is at least about 50 mm.

The overall length of the aerosol-generating article according to the invention is preferably less than or equal to 110 mm. More preferably, the overall length of the aerosol-generating article according to the invention is preferably less than or equal to 100 mm. Even more preferably, the overall length of the aerosol-generating article according to the invention is preferably less than or equal to 75 mm. Even more preferably, the overall length of the aerosol-generating article according to the invention is preferably less than or equal to 70 mm.

For example, the overall length of the aerosol-generating article may be between about 35 millimeters and about 110 millimeters, or between about 40 millimeters and about 100 millimeters, or between about 45 millimeters and about 75 millimeters, or between about 50 millimeters and about 70 millimeters.

Preferably, the aerosol-generating article has an outer diameter of at least 4 mm. Preferably, the aerosol-generating article has an outer diameter of at least 4.5 mm. More preferably, the aerosol-generating article has an outer diameter of at least 5 mm.

Preferably, the aerosol-generating article has an outer diameter of less than or equal to about 9 millimeters. More preferably, the aerosol-generating article has an outer diameter of less than or equal to about 8 millimeters. Even more preferably, the aerosol-generating article has an outer diameter of less than or equal to about 7 millimeters.

For example, the aerosol-generating article may have an outer diameter of between about 4 millimeters and about 9 millimeters, or between about 4.5 millimeters and about 8 millimeters, or between about 5 millimeters and about 7 millimeters.

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

In certain embodiments of the invention, one or more of the components of the aerosol-generating article are individually defined by their own wrapper.

Preferably, the aerosol-generating substrate and the downstream section are combined together with an outer wrapper, such as a tipping wrapper.

Preferably, the components of the aerosol-generating article according to the invention are made of biodegradable material.

Preferably, an aerosol-generating article according to the invention as described herein is suitable for use in an electrically operated aerosol-generating system, wherein the aerosol-generating substrate of the heated aerosol-generating article is heated by an electrical heat source.

The heating element of such an aerosol-generating device may be of any suitable form to conduct heat. The heating of the aerosol-generating substrate may be effected internally, externally or both internally and externally. The heating element may preferably be a heater blade or pin adapted to be inserted into the substrate such that the substrate is heated from the inside. The heating element may partially or completely surround the substrate and externally heat the substrate circumferentially from the outside.

The aerosol-generating system may be an electrically operated aerosol-generating system comprising an induction heating device. As in certain embodiments of the invention described above, the induction heating device generally comprises an induction source configured to be coupled to a susceptor, which may be arranged outside the aerosol-generating substrate or inside the aerosol-generating substrate. The induction source generates an alternating electromagnetic field that induces magnetization or eddy currents in the susceptor. Susceptors may be heated due to hysteresis losses or induced eddy currents that heat the susceptor by ohmic or resistive heating.

An electrically operated aerosol-generating system comprising an induction heating device may further comprise an aerosol-generating article having an aerosol-generating substrate and a susceptor in thermal proximity to the aerosol-generating substrate. Typically, the susceptor is in direct contact with the aerosol-generating substrate and heat is transferred from the susceptor to the aerosol-generating substrate primarily by conduction. Examples of electrically operated aerosol-generating systems with induction heating means and aerosol-generating articles with susceptors are described in WO-A1-95/27411 and WO-A1-2015/177255.

In some cases, the electrically operated aerosol-generating system may comprise an aerosol-generating article as defined above, a source of aerosol-forming agent and means for vaporising the aerosol-forming agent, preferably a heating element. The aerosol-former source may be a refillable or replaceable reservoir located on the aerosol-generating device. When the reservoir is physically separated from the aerosol-generating article, the generated vapor is directed through the aerosol-generating article. The vapor is contacted with an aerosol-generating substrate that releases volatile compounds such as nicotine and flavoring in particulate plant material to form an aerosol. Optionally, to assist in volatilisation of compounds in the aerosol-generating substrate, the aerosol-generating system may further comprise a heating element to heat the aerosol-generating substrate, preferably in a coordinated manner with the aerosol-former. However, in certain embodiments, the heating element for heating the aerosol-generating article is separate from the heater for heating the aerosol-forming agent.

As mentioned above, the hollow tubular matrix element of the aerosol-generating article according to the invention may advantageously be adapted such that the length substantially matches the longitudinal dimension of a heating element of an aerosol-generating system intended for heating the aerosol-generating article. This ensures that the hollow tubular substrate element is heated along substantially its entire length so that aerosol generation from the aerosol generating substrate can be maximised.

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: an aerosol-generating substrate comprising a hollow tubular substrate element having a peripheral wall defining a longitudinal airflow channel extending between an upstream end and a downstream end of the hollow tubular substrate element, wherein the peripheral wall is formed from one or more layers of homogenized plant material; a sealing element at an upstream end of the hollow tubular matrix element; and a downstream section disposed downstream of the aerosol-generating substrate.

Ex2 the aerosol-generating article of example EX1, wherein the sealing element is arranged to provide a hermetic seal at the upstream end of the longitudinal gas flow channel.

Ex3. the aerosol-generating article according to example EX1 or EX2, wherein the sealing element comprises a film layer.

Ex4 the aerosol-generating article of example EX3 wherein the film layer is pierceable.

Ex5 the aerosol-generating article according to example EX3 or EX4, wherein the film layer comprises one or more polymer layers.

Ex6 the aerosol-generating article of example EX5, wherein the one or more polymeric layers are formed from polyethylene terephthalate (PET), low density and high density polyethylene (LDPE and HDPE, respectively), polypropylene (PP), polyvinyl chloride (PVC), polyamide, polyolefin, polystyrene, ethylene-vinyl alcohol copolymer, or a combination thereof.

The aerosol-generating article of any of examples EX3 to EX6, wherein the film layer comprises one or more metal layers.

Ex8 the aerosol-generating article of example EX7, wherein the film layer comprises one or more layers of aluminum.

The aerosol-generating article according to any one of examples EX3 to EX8, wherein the membrane layer is heat sealed to the peripheral wall of the hollow tubular matrix element.

Ex10 the aerosol-generating article according to example EX1 or EX2, wherein the sealing element comprises a paper wrapper.

Ex11 the aerosol-generating article according to example EX10, wherein the paper wrapper is folded over the upstream end of the hollow tubular matrix element.

Ex12 an aerosol-generating article according to example EX10 or EX11, wherein the paper wrapper is provided with an impermeable coating.

Ex13 an aerosol-generating article according to example EX12 wherein the paper wrapper is coated with wax.

An aerosol-generating article according to any preceding example, wherein the sealing element is attached to the upstream end of the hollow tubular matrix element by means of an adhesive layer.

An aerosol-generating article according to any preceding example, wherein the sealing element extends downstream from the upstream end at least partially along an outer surface of the peripheral wall of the hollow tubular matrix element.

EX16 the aerosol-generating article of example EX15, wherein the sealing element extends at least 2 millimeters downstream from the upstream end along the outer surface of the peripheral wall.

The aerosol-generating formulation of example EX15 or EX16, further comprising a securing strap extending circumferentially around the hollow tubular matrix element and overlying a portion of the sealing element extending downstream from an upstream end of the hollow tubular matrix element, wherein the securing strap is attached to an outer surface of the hollow tubular matrix element.

Ex18 the aerosol-generating article of example EX17 wherein the securing strap is a paper strap.

Ex19 the aerosol-generating article of example EX17 or EX18, wherein the fixation strap has a length of at least 2 millimeters.

An aerosol-generating article according to any preceding example, wherein the longitudinal gas flow channel has a diameter of at least 3 millimeters.

An aerosol-generating article according to any preceding example, wherein the hollow tubular matrix element comprises at least 2 overlapping layers of homogenized plant material.

An aerosol-generating article according to any of the preceding examples, wherein the hollow tubular matrix element comprises up to 10 overlapping layers of homogenized plant material.

An aerosol-generating article according to any of the preceding examples, wherein the peripheral wall of the hollow tubular matrix element has a cross-sectional porosity of at least about 0.3.

An aerosol-generating article according to any of the preceding examples, wherein the peripheral wall of the hollow tubular matrix element has a cross-sectional porosity of at least about 0.7.

An aerosol-generating article according to any of the preceding examples, wherein the peripheral wall of the hollow tubular matrix element has a density of at least 200 mg/cc.

An aerosol-generating article according to any of the preceding examples, wherein the peripheral wall of the hollow tubular matrix element has a density of less than 1 gram per cubic centimeter.

An aerosol-generating article according to any of the preceding examples, wherein the peripheral wall of the hollow tubular matrix element provides a hollow tubular matrix of at least 150 milligrams of homogenized plant material per centimeter of length.

An aerosol-generating article according to any of the preceding examples, wherein the longitudinal tensile strength of the hollow tubular matrix element is between 11 kilonewtons/meter and 14 kilonewtons/meter.

An aerosol-generating article according to any of the preceding examples, wherein the axial compressive strength of the hollow tubular matrix element is between 7MPa and 9 MPa.

An aerosol-generating article according to any of the preceding examples, wherein the radial compressive strength of the hollow tubular matrix element is between 7MPa and 9 MPa.

An aerosol-generating article according to any of the preceding examples, wherein the hollow tubular matrix element has a length of up to 40 mm.

An aerosol-generating article according to any of the preceding examples, wherein the hollow tubular matrix element has a length of at least 10 mm.

An aerosol-generating article according to any of the preceding examples, wherein the ratio of the length of the hollow tubular matrix element to the overall length of the aerosol-generating article is at least 0.15.

An aerosol-generating article according to any of the preceding examples, wherein the ratio of the length of the hollow tubular matrix element to the overall length of the aerosol-generating article is up to 0.6.

An aerosol-generating article according to any of the preceding examples, wherein the hollow tubular matrix element has an outer diameter of at least 4 mm.

An aerosol-generating article according to any of the preceding examples, wherein the hollow tubular matrix element has an outer diameter of up to 9 mm.

An aerosol-generating article according to any of the preceding examples, wherein the hollow tubular matrix element provides an unrestricted flow channel.

An aerosol-generating article according to any of the preceding examples, wherein the longitudinal gas flow channels of the hollow tubular matrix element have a diameter of up to 7 mm.

An aerosol-generating article according to any of the preceding examples, wherein the ratio of the inner diameter to the outer diameter of the hollow tubular matrix element is at least 0.4.

An aerosol-generating article according to any of the preceding examples, wherein the peripheral wall has a wall thickness of at least 1 mm.

An aerosol-generating article according to any of the preceding examples, wherein the peripheral wall has a wall thickness of up to 2.25 mm.

An aerosol-generating article according to any of the preceding examples, wherein the multi-layered homogenized plant material is spirally wound around the longitudinal axis of the hollow tubular matrix element.

An aerosol-generating article according to any of the preceding examples, wherein the hollow tubular matrix element further comprises an adhesive for sealing adjacent layers to each other.

An aerosol-generating article according to any of the preceding examples, wherein the homogenized plant material is a homogenized tobacco material having a tobacco content of at least 40 weight percent on a dry weight basis.

An aerosol-generating article according to any of the preceding examples, wherein the homogenized plant material further comprises one or more aerosol-forming agents.

An aerosol-generating article according to any of the preceding examples, wherein the hollow tubular substrate element comprises one or more susceptor elements positioned in contact with the peripheral wall.

Ex47 the aerosol-generating article of example EX46, wherein the hollow tubular substrate element comprises one or more susceptor elements on a surface of the peripheral wall.

Ex48 the aerosol-generating article of example EX46, wherein the hollow tubular substrate element comprises a tubular susceptor element disposed on at least one surface of the peripheral wall.

An aerosol-generating article according to any of the preceding examples, wherein the downstream section comprises a hollow tubular element.

Ex50 the aerosol-generating article of example EX49, wherein the hollow tubular element of the downstream section has a length between 12mm and 50 mm.

Ex51. the aerosol-generating article of example EX49 or EX50, wherein the ratio between the length of the hollow tubular matrix element and the length of the hollow tubular element of the downstream section is at least 0.25.

The aerosol-generating article according to any of examples EX49 to EX51, wherein the ratio between the length of the hollow tubular matrix element and the length of the hollow tubular element of the downstream section is less than or equal to 1.25.

An aerosol-generating article according to any of examples EX49 to EX52, wherein the ratio between the length of the hollow tubular element of the downstream section and the total length of the downstream section is at least 0.35.

The aerosol-generating article according to any one of examples EX49 to EX53, wherein the ratio between the length of the hollow tubular element of the downstream section and the total length of the downstream section is less than or equal to 1.

Ex55 an aerosol-generating article according to any of examples EX49 to EX54, wherein the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article is at least 0.25.

Ex56 an aerosol-generating article according to any of examples EX49 to EX55, wherein the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article is less than or equal to 0.8.

Ex57. an aerosol-generating article according to any of examples EX49 to EX56, wherein the hollow tubular element of the downstream section has a wall thickness of at least 100 micrometers.

An aerosol-generating article according to any of examples EX49 to EX57, wherein the hollow tubular element of the downstream section has a wall thickness of less than or equal to 2 millimeters.

An aerosol-generating article according to any of examples EX49 to EX58, wherein the hollow tubular element of the downstream section has an inner diameter of between 2 and 10 millimeters.

Ex60. the aerosol-generating article of any of examples EX49 to EX59, wherein the ratio of the inner diameter of the hollow tubular matrix element to the inner diameter of the hollow tubular element of the downstream section is between 0.8 and 1.2.

An aerosol-generating article according to any of the preceding examples, wherein the downstream section further comprises a mouthpiece element.

Ex62 the aerosol-generating article of example EX61, wherein the mouthpiece element comprises at least one segment of fibrous filter material.

Ex63 an aerosol-generating article according to example EX61 or EX62, wherein the downstream section comprises an oral cavity at the downstream end downstream of the mouthpiece element.

An aerosol-generating article according to any of the preceding examples, wherein the RTD of the downstream section is not greater than 12mm H ₂ O.

An aerosol-generating article according to any of the preceding examples, wherein the downstream section is between 20 and 50 mm in length.

An aerosol-generating article according to any of the preceding examples, wherein the ratio between the total length of the downstream section and the total length of the aerosol-generating article is less than or equal to 0.80.

An aerosol-generating article according to any of the preceding examples, wherein the components of the aerosol-generating article are made of biodegradable material.

Drawings

Specific embodiments will be further described, by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 shows a schematic side cross-sectional view of an aerosol-generating article according to a first embodiment of the invention;

fig. 2 shows a schematic side cross-sectional view of an aerosol-generating article according to a second embodiment of the invention; and

Fig. 2 shows a schematic side cross-sectional view of an aerosol-generating system comprising an aerosol-generating article and an aerosol-generating device according to a third embodiment of the invention.

Detailed Description

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

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

The aerosol-generating substrate 12 comprises a hollow tubular substrate element 40 formed from a plurality of layers of homogenized tobacco material that have been helically wound about a longitudinal axis of the hollow tubular substrate element. The hollow tubular matrix element 40 has a peripheral wall 42 formed by overlapping layers of homogenized tobacco material. The peripheral wall 42 defines a central longitudinal air flow passage 44 extending through the hollow tubular matrix member 40. The hollow tubular matrix element 40 is not wrapped such that the homogenized tobacco material layer is visible on the outer surface of the aerosol generating article.

The sealing element 24 is provided at the upstream end of the hollow tubular matrix element 40. The sealing element 24 is attached to the upstream face of the peripheral wall 42 and provides an airtight seal on the upstream end of the longitudinal air flow channel 44 such that air cannot be drawn into the longitudinal air flow channel through the upstream opening. The sealing element 24 is formed from a polymer film layer.

With the sealing element 24 in place, front-to-back airflow through the article 10 is not possible. Instead, during use, air is drawn transversely through the porous peripheral wall 42 into the longitudinal air flow channels 44 where it will mix with the aerosol and be drawn to the downstream end of the article 10.

The sealing element 24 can be pierced or pierced by a suitable element within the heating chamber of the aerosol-generating device if desired. Upon piercing the sealing element, a longitudinal air flow is achieved through the longitudinal air flow channel 44. Air may thus be drawn through the pierced upstream element 24 in the longitudinal direction and through the hollow tubular matrix element 40.

The hollow tubular member 20 of the downstream section 14 is located immediately downstream of the hollow tubular matrix member 40, the hollow tubular member 20 being longitudinally aligned with the aerosol-generating substrate 12. The upstream end of the hollow tubular member 20 abuts the downstream end of the hollow tubular matrix member 40.

The hollow tubular member 20 is provided in the form of a hollow cylindrical tube made from cellulose acetate tow. The hollow tubular member 20 defines an inner lumen 22 extending from the upstream end of the hollow tubular member 20 all the way to the downstream end of the hollow tubular member 20. The lumen 22 is substantially empty and thus a substantially non-limiting flow of air is achieved along the lumen 22. The hollow tubular element 20 does not substantially affect the overall RTD of the aerosol-generating article 10. The RTD of the hollow tubular element 20 is thus about 0mm H ₂ O.

As shown in fig. 1, the inner diameter of the hollow tubular element 20 of the downstream section 14 is substantially the same as the inner diameter of the hollow tubular matrix element 40.

The mouthpiece element 50 extends from the downstream end of the hollow tubular element 20 to the downstream or mouth end 18 of the aerosol-generating article 10. The mouthpiece element 50 comprises a low density cellulose acetate filter segment. The mouthpiece element 50 may be individually packaged by a rod wrapper (not shown).

The article 10 includes a tipping wrapper 52 defining the hollow tubular element 20 and the mouthpiece element 50. The tipping wrapper 52 additionally overlies the upstream portion of the hollow tubular matrix member 40 so as to join the hollow tubular matrix member 40 and the downstream section 14.

The aerosol-generating article 10 is particularly suitable for use with an aerosol-generating device comprising external heating means for heating the aerosol-generating substrate 12 from the outside. During use, the aerosol-generating article 10 is thus preferably inserted into a heating cavity of an aerosol-generating device, wherein the outer surface of the hollow tubular matrix element 40 is proximate to one or more heating elements within the cavity. When a consumer draws on the article, the heating of the hollow tubular substrate element 40 generates an aerosol from the homogenized tobacco layer, which aerosol is drawn through the peripheral wall 42 and into the longitudinal air flow channel 44 of the hollow tubular substrate element 40, together with the air entering the longitudinal air flow channel 44 at the upstream end. The combined air and aerosol is drawn through the aerosol-generating article 10 and delivered from the downstream end of the aerosol-generating article 10 to the consumer.

Fig. 2 shows an aerosol-generating article 110 according to a second embodiment of the invention. The aerosol-generating article 110 has a similar construction to the aerosol-generating article 10 of fig. 1 having the same components as described above. However, the aerosol-generating article 110 further comprises a paper strap 26 defining the hollow tubular matrix element 20 at the upstream end. The paper strap 26 extends approximately 3mm from the upstream end of the hollow tubular matrix member 20 and is made of standard tipping paper material. Which is adhered to the exterior of the hollow tubular matrix member 20 by means of a suitable adhesive. Paper strap 26 helps to hold sealing element 24 in place at the upstream end of hollow tubular matrix element 20 and provides a more consistent appearance.

Fig. 3 shows an aerosol-generating system 100 comprising an aerosol-generating device 102 and an aerosol-generating article 10 according to a first embodiment of the invention as described above.

As shown in fig. 3, the aerosol-generating device 102 comprises a longitudinal heating chamber 104 for receiving an aerosol-generating article 210. The heating chamber 104 has a closed distal end and an open mouth end. The airflow inlet 106 is provided at the distal end of the cavity such that air may be drawn through the aerosol-generating article 210 during use. The heating chamber 104 comprises an arrangement of peripheral heating elements 108 for externally heating the hollow tubular matrix element of the aerosol-generating article 10 during use.

The aerosol-generating device 102 further comprises a power supply (not shown) for supplying power to the inductor coil 108 and a controller (not shown) for controllably heating the aerosol-generating article 110 during use when the aerosol-generating article 210 is received within the device 102.

As shown in fig. 3, the aerosol-generating article 10 is inserted into the heating chamber 104, wherein the sealing element 24 is still intact on the upstream end of the hollow tubular matrix element 40. Thus, longitudinal air flow through the longitudinal air flow channels 44 is prevented. Instead, air entering the heating chamber 104 through the air flow inlet 106 is drawn laterally through the peripheral wall 42 of the hollow tubular matrix member 40 and into the longitudinal air flow channel 44. This advantageously assists in drawing aerosol generated from the homogenized tobacco material layer in the peripheral wall 42 into the longitudinal airflow channel 44.

Claims

1. An aerosol-generating article comprising:

An aerosol-generating substrate comprising a hollow tubular substrate element having a peripheral wall defining a longitudinal airflow channel extending between an upstream end and a downstream end of the hollow tubular substrate element, wherein the peripheral wall is formed from one or more layers of homogenized plant material;

A sealing element at an upstream end of the hollow tubular matrix element, wherein the sealing element is arranged to provide a substantially airtight seal at an upstream end of the longitudinal gas flow channel; and

A downstream section disposed downstream of the aerosol-generating substrate.

2. An aerosol-generating article according to claim 1, wherein the sealing element comprises a membrane layer attached to the peripheral wall at an upstream end of the hollow tubular matrix element.

3. An aerosol-generating article according to claim 2, wherein the film layer is pierceable.

4. An aerosol-generating article according to claim 2 or 3, wherein the film layer comprises one or more polymer layers.

5. An aerosol-generating article according to claim 2, 3 or 4, wherein the film layer comprises one or more metal layers.

6. An aerosol-generating article according to any one of claims 2 to 5, wherein the membrane layer is heat sealed to the peripheral wall of the hollow tubular matrix element.

7. An aerosol-generating article according to claim 1, wherein the sealing element comprises a paper wrapper folded over an upstream end of the hollow tubular matrix element.

8. An aerosol-generating article according to claim 7, wherein the paper wrapper is provided with an impermeable coating.

9. An aerosol-generating article according to any preceding claim, wherein the sealing element is attached to the upstream end of the hollow tubular matrix element by means of an adhesive layer.

10. An aerosol-generating article according to any preceding claim, wherein the sealing element extends downstream from the upstream end at least partially along an outer surface of a peripheral wall of the hollow tubular matrix element.

11. An aerosol-generating article according to claim 10, further comprising a securing strap extending circumferentially around the hollow tubular matrix element and overlying a portion of the sealing element extending downstream from an upstream end of the hollow tubular matrix element, wherein the securing strap is attached to an outer surface of the hollow tubular matrix element.

12. An aerosol-generating article according to claim 11, wherein the securing strap is a paper strap.

13. An aerosol-generating article according to any preceding claim, wherein the longitudinal airflow channels have a length of at least 3 mm.

14. An aerosol-generating article according to any preceding claim, wherein the peripheral wall of the hollow tubular matrix element has a cross-sectional porosity of at least 0.3.

15. An aerosol-generating article according to any preceding claim, wherein the aerosol-generating substrate further comprises a tubular susceptor element on at least one surface of the hollow tubular substrate element.