Aerosol-generating article with tubular element and ventilation

Abstract

An aerosol-generating article comprises a plurality of elements assembled in the form of a rod (11). The elements comprise a first element (100, 11) having an aerosol-generating substrate and a tubular element (100, 200, 300, 500, 600, 700, 800) upstream or downstream of the first element (100, 11). The tubular element (100, 200, 300, 500, 600, 700, 800) comprises a tubular body (103, 203) defining a lumen (106, 206, 606) extending from a first end (101) of the tubular body (103, 203) to a second end (102) of the tubular body (103, 203) and a folded end portion forming a first end wall (104, 105, 204A, 604, 804) at the first end (101) of the tubular body (103, 203). The first end wall (104, 105, 204A, 604, 804) delimits an opening (105, 205A, 205B, 605B, 605) for airflow between the lumen (106, 206, 606) of the tubular element (100, 200, 300, 500, 600, 700, 800) and the exterior.

Description

TECHNICAL FIELD

[0001] The present application relates to an aerosol-generating article comprising an aerosol- generating substrate and adapted to generate an inhalable aerosol upon heating. BACKGROUND

[0002] 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. Typically, in such heated smoking articles, an aerosol is generated by the transfer of heat from a heat source to a physically separate aerosol-generating substrate or material that can 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 compounds cool, they condense to form an aerosol.

[0003] 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 the transfer of heat from one or more electrically heated 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 comprising an internal heating blade adapted to be inserted into an aerosol-generating substrate have been proposed. As an alternative, inductively heatable aerosol-generating articles comprising an aerosol-generating substrate and a susceptor element arranged within the aerosol-generating substrate have been proposed by WO 2015 / 176898.

[0004] Aerosol-generating articles in which a tobacco-containing substrate is heated rather than combusted present a number of challenges not encountered with conventional smoking articles. For example, it can be desirable to limit the movement of the aerosol-generating substrate within the aerosol-generating article while still ensuring that sufficient levels of airflow can pass through the aerosol-generating substrate and the aerosol-generating article. Limiting the potential movement of the aerosol-generating substrate is particularly desirable as this can, for example, help to improve the consistency of performance from one article to another by helping to increase the consistency of the interaction between the aerosol-generating substrate and the heater element. This can be particularly applicable to aerosol-generating articles adapted to receive a heater blade as the action of inserting the heater blade can otherwise increase the likelihood of displacement of the aerosol-generating substrate.

[0005] WO 2013 / 098405 proposes a support element comprising the aerosol- generating substrate immediately downstream. The support element is provided in the form of a ring-shaped tube of filter material, commonly referred to as a hollow acetate tube. The support element is configured to resist downstream movement of the aerosol-generating substrate during insertion of a heating blade of an aerosol-generating device into the aerosol-generating substrate. The empty space within the hollow support element provides an opening for the flow of aerosol from the aerosol-generating substrate towards the mouth end of the aerosol-generating article.

[0006] However, some support elements, such as hollow acetate tubes, can undesirably filter some volatile compounds released from the aerosol-generating substrate. Furthermore, some support elements can not provide the desired RTD characteristics for the aerosol-generating article. Prior art support elements, such as hollow acetate tubes, can also be expensive, or expensive and complex to manufacture. Prior art support elements, such as hollow acetate tubes, can also be undesirably suited to the temperatures generated by the susceptor element in aerosol-generating articles in which the susceptor element is arranged within the aerosol-generating substrate. For example, because prior art support elements can not be desirably suited to the temperatures generated by the susceptor element. SUMMARY

[0007] It would therefore be desirable to provide a new and improved aerosol-generating article adapted to achieve at least one of the above-mentioned desirable results. Furthermore, it would be desirable to provide an aerosol-generating article of this kind which can be manufactured efficiently and at high speed, preferably with satisfactory RTD and low RTD variability from one article to another.

[0008] The present disclosure relates to an aerosol-generating article.

[0009] The present disclosure relates to a tubular element for an aerosol-generating article. The tubular element can comprise a tubular body defining a lumen. The lumen can extend from a first end of the tubular body to a second end of the tubular body. The tubular element can further comprise a folded end portion forming a first end wall at the first end of the tubular body. The first end wall can delimit an opening for airflow between the lumen of the tubular element and the exterior. The tubular element can comprise a ventilation zone at a location along the tubular body of the tubular element.

[0010] The present disclosure also relates to an aerosol-generating article comprising a tubular element. The aerosol-generating article can comprise a plurality of elements assembled in the form of a rod. The plurality of elements can comprise a first element comprising an aerosol-generating substrate. The plurality of elements can comprise a tubular element upstream or downstream of the first element. The first end wall of the tubular element can be adjacent to the aerosol-generating substrate.

[0011] The aerosol-generating article can further comprise an outer wrapper surrounding at least the tubular element.

[0012] The outer wrapper can define an outer surface of the aerosol-generating article. The outer wrapper can also surround the first element. The outer wrapper can surround all of the plurality of elements of the aerosol-generating article assembled in the form of a rod. As described below, the outer wrapper can be a tipping wrapper. The outer wrapper surrounding the tubular element can be a paper wrapper or a non-paper wrapper. Suitable paper wrappers for use in particular embodiments of the application are known in the art and include, but are not limited to: cigarette paper; and filter plug wrap. Suitable non-paper wrappers for use in particular embodiments of the application are known in the art and include, but are not limited to: sheets of homogenised tobacco material. In certain preferred embodiments, the wrapper can be formed from a laminate comprising a plurality of layers. Preferably, the wrapper is formed from an aluminium co-laminate sheet. The use of a co-laminate sheet comprising aluminium advantageously prevents combustion of the outer wrapper in the event that the aerosol-generating substrate is intended to be lit rather than heated in the intended manner.

[0013] According to the present application, there is provided a tubular element for an aerosol-generating article. The tubular element comprises: a tubular body defining a cavity extending from a first end of the tubular body to a second end of the tubular body; and a folded end portion forming a first end wall at the first end of the tubular body, the first end wall delimiting an opening for airflow between the cavity of the tubular element and the exterior. The tubular element further comprises a ventilation zone at a location along the tubular body of the tubular element.

[0014] The term "aerosol-generating article" is used herein to mean an article in which an aerosol-generating substrate is heated to generate an inhalable aerosol and deliver it to a consumer. As used herein, the term "aerosol-generating substrate" means a substrate capable of releasing volatile compounds upon heating to generate an aerosol.

[0015] A conventional cigarette will be lit when a user applies a flame to one end of the cigarette and draws air through the other end. The localised heat provided by the flame and the oxygen in the air drawn through the cigarette causes the end of the cigarette to be ignited and the combustion formed generates an inhalable smoke. In contrast, in a heated aerosol-generating article, an aerosol is generated by heating a flavour-generating substrate, such as tobacco. Known heated aerosol-generating articles 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 physically separate aerosol-forming material. For example, aerosol-generating articles according to the present application have particular application in aerosol-generating systems comprising electrically heated aerosol-generating devices having an internal heater blade adapted to be inserted into a rod of aerosol-generating substrate. Aerosol-generating articles of this type are described in the prior art, for example, in European Patent Application EP 0822670.

[0016] As used herein, the term "aerosol-generating device" refers to a device comprising a heater element that interacts with an aerosol-generating substrate of an aerosol-generating article to generate an aerosol.

[0017] As used herein, the term "rod" is used to denote a generally cylindrical element having a substantially circular, oval or elliptical cross-section.

[0018] As used herein, the term "longitudinal" refers to a direction corresponding to a main longitudinal axis of the aerosol-generating article, which direction extends between an upstream end and a downstream end of the aerosol-generating article. As used herein, the terms "upstream" and "downstream" describe the relative position of elements or portions of elements of the aerosol-generating article with respect to the direction of the aerosol's transport through the aerosol-generating article during use.

[0019] During use, air is drawn through the aerosol-generating article in the longitudinal direction. The term "transverse" refers to a direction perpendicular to the longitudinal axis. Unless otherwise stated, any reference to a "cross-section" of the aerosol-generating article or a component of the aerosol-generating article refers to a transverse cross-section.

[0020] The term "length" denotes the dimension of a component of the aerosol-generating article in the longitudinal direction. For example, it can be used to denote the dimension of a first element comprising an aerosol-generating substrate or a hollow tubular element in the longitudinal direction.

[0021] As used herein, the term "tubular element" is used to denote a generally elongated element defining an internal cavity or airflow passage along its longitudinal axis. In particular, the term "tubular" will be used hereinafter with reference to a tubular element having a tubular body having a substantially cylindrical cross-section and defining at least one airflow conduit establishing uninterrupted fluid communication between an upstream end of the tubular body and a downstream end of the tubular body. However, it will be appreciated that alternative geometrical shapes of the tubular body, e.g. alternative cross-sectional shapes, can be possible.

[0022] As used herein, the term "elongated" means that the length dimension of an element is greater than its width dimension or its diameter dimension, e.g. two times or more.

[0023] In the context of the present invention, the tubular body of the tubular element provides a non-restrictive flow passage. This means that the tubular body portion of the tubular element provides a negligible level of resistance to draw (RTD). Accordingly, the flow passage should be free of any components that would impede the flow of air in the longitudinal direction. Preferably, the flow passage is substantially empty. In this case, the tubular body of the tubular element defines a cavity.

[0024] The tubular element of the present invention provides an improved component for an aerosol-generating article. By forming the tubular element from a tubular body defining a cavity extending from a first end of the tubular body to a second end of the tubular body, a relatively large proportion of the tubular element can be hollow and allow unimpeded airflow. This can help to improve the cooling and nucleation of aerosol when the tubular element is downstream of an aerosol-generating substrate. Furthermore, such a configuration can also help to minimise filtration of any compounds released from the aerosol-generating substrate, particularly when compared to a hollow acetate tube of the prior art.

[0025] By providing the tubular element with a folded end portion forming a first end wall at the first end of the tubular body, the tubular element can be configured to have a desired RTD by the configuration of the size and shape of the first end wall. In particular, the tubular element and its first end wall can be manufactured efficiently and at high speed, with a satisfactory RTD and low RTD variability between different articles. Furthermore, the configuration of the tubular element and its first end wall means that the RTD can be localised at a particular longitudinal position of the tubular element, rather than being distributed continuously along the length of the tubular element.

[0026] With the first end wall of the tubular element adjacent to the aerosol-generating substrate, the first end wall can provide a barrier capable of limiting movement of the aerosol-generating substrate. This arrangement can also advantageously enable one or both of air and aerosol to flow through the opening into the cavity.

[0027] The barrier provided by the first end wall of the tubular element can be more effective than the barrier provided by the end of a hollow acetate tube, as the first end wall can be less deformable than the end of a hollow acetate tube. The construction of the tubular element can also be more suitable to withstand the temperatures generated by a heating blade or susceptor element.

[0028] The term "adjacent" when used herein in relation to the tubular element and the first element means that the tubular element is positioned longitudinally adjacent to the first element in an assembled element rod. In particular, the term means that no other assembled rod element is arranged between the first element and the tubular element in the longitudinal direction.

[0029] The first element and the tubular element can be adjacent to and in contact with each other. For example, the first end wall of the tubular element can be adjacent to and in contact with the aerosol-generating substrate.

[0030] The first element and the tubular element can be adjacent to but not in contact with each other, as a small gap of empty space separates the first element from the tubular element in the longitudinal direction of the aerosol-generating article. For example, the first end wall of the tubular element can be adjacent to but not in contact with the aerosol-generating substrate. The gap can be 2 millimetres or less. The gap can be 1 millimetre or less.

[0031] The first element can be referred to as an aerosol-generating element.

[0032] The tubular element can be located upstream of the first element. In such embodiments, the tubular element can be referred to as an upstream tubular element.

[0033] The tubular element can be located downstream of the first element. In such embodiments, the tubular element can be referred to as a downstream tubular element.

[0034] The aerosol-generating article can comprise two tubular elements, one being a first tubular element located downstream of the first element and the other being a second tubular element located upstream of the first element. The first and second tubular elements can each have any of the features or combinations of features described above or below in relation to the tubular elements of the application.

[0035] For example, the tubular element can be a first tubular element located downstream of the aerosol-forming substrate, wherein a first end wall of the first tubular element is adjacent to a downstream end of the aerosol-forming substrate. In such embodiments, the aerosol-generating article can further comprise a second tubular element. The second tubular element can be located upstream of the first element. The second tubular element can comprise: a tubular body defining a cavity extending from a first end of the tubular body to a second end of the tubular body; and a folded end portion forming a first end wall at the first end of the tubular body, the first end wall delimiting an opening for airflow between the cavity of the second tubular element and the exterior. The first end wall of the second tubular element can be adjacent to an upstream end of the aerosol-forming substrate. Thus, in such embodiments, the first element comprising the aerosol-forming substrate can be sandwiched between the first and second tubular elements, with each tubular element having a folded end portion that provides a respective end wall adjacent to an upstream or downstream end of the first element. In such embodiments, the second tubular element can be referred to as an upstream tubular element and the first tubular element can be referred to as a downstream tubular element.

[0036] The second tubular element can further comprise a folded end portion forming a second end wall at the second end of its tubular body. The second end wall of the second tubular element can delimit an opening for airflow between the cavity of the second tubular element and the exterior. The opening delimited by the second end wall of the second tubular element can be smaller than the opening delimited by the first end wall of the second tubular element. For example, the size of the opening delimited by the second end wall of the second tubular element can be between about 20% and about 80% of the size of the opening delimited by the first end wall of the second tubular element. The size of the opening delimited by the second end wall of the second tubular element can be between about 40% and about 60% of the size of the opening delimited by the first end wall of the second tubular element, more preferably between about 45% and about 55% of the size of the opening delimited by the first end wall of the second tubular element.

[0037] Generally, where the tubular element of the application comprises two end walls each having a respective opening, the size of the opening defined by the second end wall of the tubular element can be between about 20% and about 80% of the size of the opening defined by the first end wall of the tubular element.

[0038] The second tubular element can be the most upstream component of the aerosol- generating article. For example, the upstream end of the aerosol-generating article can be defined by the upstream end of the second tubular element.

[0039] As will be described in more detail below, the aerosol-generating article can also comprise a ventilation zone at a location along the tubular element. Where the aerosol- generating article comprises the first and second tubular elements described above, the ventilation zone is preferably located along the first tubular element.

[0040] The first end wall can extend substantially transversely to the longitudinal direction of the aerosol-generating article. The first end wall can extend substantially transversely to the longitudinal direction of the tubular body.

[0041] The first end wall can extend partially into the cavity of the tubular body and form an angle of less than 90 degrees with the inner surface of the tubular body, more preferably an angle of less than 80 degrees with the inner surface of the tubular body, even more preferably an angle of less than 70 degrees with the inner surface of the tubular body. This can be achieved by ensuring that a folding force is applied to the tubular element during manufacture of the tubular element such that at least a portion of the first end portion of the tubular element is pushed into the cavity of the tubular body. Such an arrangement can advantageously increase the likelihood that the first end wall remains stationary relative to the tubular body after the tubular element has been manufactured. In particular, such an arrangement can help to overcome any natural elasticity in the material from which the tubular element is formed, such that the folded end portion of the tubular element is less likely to recover towards its pre-folded state after manufacture.

[0042] The opening defined by the first end wall can be the only opening in the first end wall. The opening can be provided in a generally radially central position of the tubular element. The first end wall can be generally annular.

[0043] The first end wall can extend from a fold point on the tubular element and towards a radially central position of the tubular element. The fold point can generally correspond to the first end of the tubular body of the tubular element.

[0044] Preferably, at least the first portion of the tubular element forming the first end wall is substantially air impermeable. In other words, preferably, the first end wall is substantially non-porous. Preferably, the first end wall does not comprise any perforations. The material forming the first end wall can have a porosity of less than 2000 Coresta units. The material forming the first end wall can have a porosity of less than 1000 Coresta units. The material forming the first end wall can have a porosity of less than 500 Coresta units.

[0045] In the case where the first element comprises a susceptor element within the aerosol- generating substrate, the opening in the first wall can be substantially aligned with the radial position of the susceptor element. This can advantageously help to maintain the distance between the first end wall of the tubular element and the susceptor of the first element. Maintaining this distance can help to mitigate any undesirable heating of the first end wall of the tubular element by the susceptor element.

[0046] The present disclosure also includes a method of forming a tubular element for an aerosol- generating article of the invention. The method can comprise the step of providing a tubular element precursor comprising: a tubular body defining a cavity extending from a first end of the tubular body to a second end of the tubular body; and a first end portion adjacent to and integrally formed with the first end of the tubular body. The method further comprises the step of applying a folding force to the tubular element precursor to bend or fold the first end portion about a folding point corresponding to the first end of the tubular body, the folding force being applied such that at least a portion of the first end portion of the tubular element extends into the cavity of the tubular body. The method can further comprise the step of releasing the folding force such that the first end portion of the tubular element partially returns along its folding path and reaches a position in which the first end portion extends substantially transversely to the longitudinal direction of the tubular body, thereby forming a first end wall at the first end of the tubular body, wherein the first end wall bounds an opening for airflow between the cavity of the tubular element and the exterior.

[0047] The present disclosure also includes a tubular element for an aerosol-generating article. The tubular element can comprise: a tubular body defining a cavity extending from a first end of the tubular body to a second end of the tubular body; a first folded end portion forming a first end wall at the first end of the tubular body, the first end wall bounding a first opening for airflow between the cavity of the tubular element and the exterior; and a second folded end portion forming a second end wall at the second end of the tubular body, the second end wall bounding a second opening for airflow between the cavity of the tubular element and the exterior. The tubular element can comprise or be combined with any feature or combination of features described above or below in relation to the tubular element of the aerosol-generating article of the invention.

[0048] The outer diameter of the tubular element is preferably substantially equal to the outer diameter of the aerosol-generating article. Where the first element is formed as a rod, the outer diameter of the tubular element is preferably substantially equal to the outer diameter of the first element.

[0049] The tubular element can have an outer diameter of between 6 and 10 millimetres, for example between 7 and 9 millimetres or between 7.5 and 8.5 millimetres. In preferred embodiments, the tubular element has an outer diameter of 7.8 millimetres + / - 10%.

[0050] Preferably, the tubular element has an equivalent internal diameter of at least about 5.5 millimetres. More preferably, the tubular element has an equivalent internal diameter of at least about 6 millimetres. Even more preferably, the tubular element has an equivalent internal diameter of at least about 7 millimetres. The term "equivalent internal diameter" is used herein to mean the diameter of a circle having the same surface area of the cross-section of the airflow conduit defined by the interior of the hollow tubular segment. The cross-section of the airflow conduit can have any suitable shape. However, as briefly described above, a circular cross-section is preferred, i.e. the hollow tubular segment is effectively a cylindrical tube. In this case, the equivalent internal diameter of the hollow tubular segment effectively coincides with the internal diameter of the cylindrical tube.

[0051] The equivalent internal diameter of the hollow tubular segment is preferably less than about 10 millimetres. More preferably, the equivalent internal diameter of the hollow tubular segment is less than about 9.5 millimetres, even more preferably less than 9 millimetres.

[0052] Preferably, the tubular element has a wall thickness of at least about 0.1 millimetres, more preferably at least about 0.2 millimetres.

[0053] Preferably, the tubular element has a wall thickness of less than about 1.5 millimetres, preferably less than about 1.25 millimetres. In preferred embodiments, the tubular element has a wall thickness of less than about 1 millimetre.

[0054] Accordingly, the tubular element preferably has a wall thickness of between about 0.1 millimetres and about 1.5 millimetres, or between about 0.2 millimetres and about 1.25 millimetres, or between about 0.5 millimetres and about 1 millimetre.

[0055] Providing the tubular element with such a wall thickness can help to improve the resistance of the tubular body to collapse or deformation, whilst still enabling the first end wall to be formed from the folded end portion of the tubular element.

[0056] The wall thickness of the tubular element can be the same as the wall thickness of one or both of the tubular body and the first end wall.

[0057] The length of the tubular element can be substantially the same as the length of the tubular body.

[0058] Preferably, the tubular element has a length of at least about 10 millimetres, more preferably at least about 15 millimetres.

[0059] Preferably, the tubular element has a length of less than about 30 millimetres, preferably less than about 25 millimetres, even more preferably less than about 20 millimetres.

[0060] The tubular element can have a length of about 10 millimetres to about 30 millimetres, preferably about 15 millimetres to about 25 millimetres, more preferably about 15 millimetres to about 20 millimetres. For example, in one particularly preferred embodiment, the tubular element has a length of 18 millimetres. Such a length can be particularly preferred in embodiments in which the tubular element is positioned downstream of the aerosol- generating substrate with the first end wall of the tubular element adjacent the downstream end of the aerosol-generating substrate.

[0061] The tubular element can have a length of about 5 millimetres to about 20 millimetres, preferably about 8 millimetres to about 15 millimetres, more preferably about 10 millimetres to about 13 millimetres. For example, in one particularly preferred embodiment, the tubular element has a length of 12 millimetres. Such a length can be particularly preferred in embodiments in which the tubular element is positioned upstream of the aerosol-generating substrate with the first end wall of the tubular element adjacent the upstream end of the aerosol-generating substrate.

[0062] Preferably, the tubular element is adapted to generate an RTD of between about 0 millimetres H20 (about 0 Pa) and about 20 millimetres H20 (about 100 Pa), more preferably between about 0 millimetres H20 (about 0 Pa) and about 10 millimetres H20 (about 100 Pa).

[0063] The tubular element is preferably formed from a paper material, for example paper, paperboard or cardboard. The tubular element can be formed from a plurality of overlapping paper layers, for example a plurality of parallel wound paper layers or a plurality of spiral wound paper layers. Forming the tubular element from a plurality of overlapping paper layers can help to improve the resistance of the tubular body to collapse or deformation, whilst still enabling the first end wall to be formed from the folded end portion of the tubular element.

[0064] The tubular element can comprise at least two paper layers. The tubular element can comprise fewer than eleven paper layers.

[0065] Where the tubular element is formed from a paper material, the paper material can have a basis weight of at least about 90 grams per square metre. The paper material can have a basis weight of less than about 300 grams per square metre. The paper material can have a basis weight of about 100 grams per square metre to about 200 grams per square metre. Providing the tubular element with such a wall basis weight can help to improve the resistance of the tubular body to collapse or deformation, whilst still enabling the first end wall to be formed from the folded end portion of the tubular element.

[0066] The first end wall of the tubular element can comprise a hydrophobic region comprising a hydrophobic group covalently bound to the first end wall. Where the tubular element comprises a second end wall, the second end wall can also comprise a hydrophobic region.

[0067] In another aspect, the hydrophobic region has a water contact angle of at least about 90 degrees or at least about 100 degrees, and a Cobb measurement (at 60 seconds) of about 40 g / m 2 or less, or about 35 g / m 2 or less.

[0068] The hydrophobic region can be prepared by a method comprising the steps of applying a liquid composition comprising a fatty acid halide to a surface of the first end wall and maintaining the surface at a temperature of about 120 degrees Celsius to about 180 degrees Celsius. The fatty acid halide reacts in situ with the native groups of the material in the hydrophobic region, resulting in the formation of a fatty acid ester.

[0069] The term "hydrophobic" means that the surface exhibits water repellent properties. One useful method of determining this is to measure the water contact angle. The "water contact angle" is the angle through the liquid conventionally measured when a liquid / vapor interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid via the Young equation.

[0070] The hydrophobic region has a Cobb water absorption (ISO 535:1991) value (at 60 seconds) of less than about 40 g / m 2 , less than about 35 g / m 2 , less than about 30 g / m 2 , or less than about 25 g / m 2 .

[0071] The hydrophobic region has a water contact angle of at least about 90 degrees, at least about 95 degrees, at least about 100 degrees, at least about 110 degrees, at least about 120 degrees, at least about 130 degrees, at least about 140 degrees, at least about 150 degrees, at least about 160 degrees, or at least about 170 degrees. Hydrophobicity is determined by testing with TAPPI T558 om-97, and the results are presented as the interfacial contact angle and reported in "degrees," and can range from close to zero degrees to close to 180 degrees. When the contact angle is not specified along with the term hydrophobic, the water contact angle is at least 90 degrees.

[0072] According to the present disclosure, there is provided an aerosol-generating article for generating an inhalable aerosol upon heating. The aerosol-generating article comprises a first element comprising an aerosol-generating substrate and a tubular element. The aerosol-generating article comprises a downstream section at a location downstream of the aerosol-generating substrate. The downstream section can comprise one or more downstream elements, such as a tubular element.

[0073] The downstream section can comprise a mouthpiece element. The mouthpiece element can extend all the way to the mouth end of the aerosol-generating article.

[0074] The mouthpiece element can extend all the way to the downstream end of the aerosol- generating substrate. In cases where the mouthpiece element extends all the way from the downstream end of the aerosol-generating substrate to the mouth end of the aerosol-generating article, the mouthpiece element can be the only element in the downstream section of the aerosol-generating article. As an alternative, the mouthpiece element can be located downstream of the first tubular element when a tubular element is provided downstream of the aerosol-generating substrate. In such embodiments, the mouthpiece element can extend all the way to the downstream end of the tubular element. In other words, the mouthpiece element is located immediately downstream of the tubular element. For example, the mouthpiece element can abut the downstream end of the tubular element.

[0075] The mouthpiece element can preferably be located at the downstream end or mouth end of the aerosol-generating article. The mouthpiece element preferably comprises at least one mouthpiece filter section for filtering aerosol generated by the aerosol-generating substrate. For example, the mouthpiece element can comprise one or more segments of fibrous filter material. Suitable fibrous filter materials will be known to the skilled person. Particularly preferably, the at least one mouthpiece filter section comprises a cellulose acetate filter section formed from cellulose acetate tow.

[0076] The mouthpiece element can be constituted by a single mouthpiece filter section. In alternative embodiments, the mouthpiece element comprises two or more mouthpiece filter sections axially aligned with one another in abutting end-to-end relationship.

[0077] The mouthpiece element can comprise a mouth end cavity. The mouth end cavity can be defined by a hollow tubular element provided at the downstream end of the mouthpiece. Alternatively, the mouth end cavity can be defined by the outer wrapper of the aerosol-generating article at the mouth end.

[0078] The mouthpiece element can optionally comprise a flavourant, which can be provided in any suitable form. For example, the mouthpiece element can comprise one or more capsules, beads or granules of flavourant, or one or more flavour-laden threads or filaments.

[0079] Preferably, the mouthpiece element has a low particulate filtration efficiency.

[0080] Preferably, the mouthpiece is formed from a segment of fibrous filter material.

[0081] Preferably, the mouthpiece element is defined by a filter segment wrapper. Preferably, the mouthpiece element is non-ventilated, such that air does not enter the aerosol-generating article along the mouthpiece element.

[0082] The mouthpiece element is preferably connected to one or more of the adjacent upstream components of the aerosol-generating article, such as one or more tubular elements, by means of a tipping wrapper.

[0083] Preferably, the mouthpiece element has an RTD of less than about 25 mm H20. More preferably, the mouthpiece element has an RTD of less than about 20 mm H20. Even more preferably, the mouthpiece element has an RTD of less than about 15 mm H20.

[0084] An RTD value of about 10 mm H20 to about 15 mm H20 is particularly preferred, as a mouthpiece element having one such RTD is expected to contribute minimally to the overall RTD of the aerosol-generating article, imposing substantially no filtration on the aerosol delivered to the consumer.

[0085] Preferably, the mouthpiece element has an outer diameter substantially equal to the outer diameter of the aerosol-generating article. The mouthpiece element can have an outer diameter of between about 5 mm and about 10 mm, or between about 6 mm and about 8 mm. In preferred embodiments, the mouthpiece element has an outer diameter of about 7.2 mm.

[0086] The mouthpiece element can have a length of at least about 10 mm, more preferably at least about 11 mm, more preferably at least about 12 mm. The mouthpiece element can have a length of less than about 25 mm, more preferably less than about 20 mm, more preferably less than about 15 mm.

[0087] The mouthpiece element can have a length of about 10 mm to about 25 mm, more preferably about 10 mm to about 20 mm, even more preferably about 10 mm to about 15 mm. The mouthpiece element can have a length of about 11 mm to about 25 mm, more preferably about 11 mm to about 20 mm, even more preferably about 11 mm to about 15 mm. The mouthpiece element can have a length of about 12 mm to about 25 mm, more preferably about 12 mm to about 20 mm, even more preferably about 12 mm to about 20 mm.

[0088] In preferred embodiments, the mouthpiece element has a length of about 12 mm.

[0089] Providing a relatively long mouthpiece element in the aerosol-generating article can allow for the inclusion of a capsule, or can allow the article to be more rigid at the location where the user applies the lip, or can allow for both.

[0090] The aerosol-generating article can comprise a ventilation zone at a location along the downstream segment. Where the downstream segment comprises a tubular element, the ventilation zone can be provided at a location along the tubular element.

[0091] The tubular element of the present application can comprise a ventilation zone at a location along the tubular body of the tubular element. The features of the ventilation zone are described below in relation to the aerosol-generating article. However, it will be appreciated that they can also be applied directly to the tubular element itself.

[0092] The ventilation zone can be located between about 5 millimetres and about 15 millimetres from the folded end portion of the tubular element. The ventilation zone can be located at least 2 millimetres from the folded end portion of the tubular element, more preferably at least 3 millimetres from the folded end portion of the tubular element, even more preferably at least 5 millimetres from the folded end portion of the tubular element.

[0093] The ventilation zone can be located less than 20 millimetres from the folded end portion of the tubular element, more preferably less than 15 millimetres from the folded end portion of the tubular element, even more preferably less than 10 millimetres from the folded end portion of the tubular element.

[0094] Where the tubular element is a first tubular element located downstream of the aerosol-forming substrate, the ventilation zone is preferably located in a downstream section of the first tubular element. Preferably, the ventilation zone is located between about 1 millimetres and about 10 millimetres from the downstream end of the first tubular element, more preferably between about 2 millimetres and about 8 millimetres from the downstream end of the first tubular element, even more preferably between about 3 millimetres and about 6 millimetres from the downstream end of the first tubular element.

[0095] Preferably, the ventilation zone is located at least 1 millimetres from the downstream end of the first tubular element, more preferably the ventilation zone is located at least 2 millimetres from the downstream end of the first tubular element, even more preferably the ventilation zone is located at least 3 millimetres from the downstream end of the first tubular element.

[0096] Preferably, the ventilation zone is located less than 10 millimetres from the downstream end of the first tubular element, more preferably the ventilation zone is located less than 8 millimetres from the downstream end of the first tubular element, even more preferably the ventilation zone is located less than 6 millimetres from the downstream end of the first tubular element.

[0097] The ventilation zone can comprise a plurality of perforations through the peripheral wall of a ventilation element, which can be the tubular element. Preferably, the ventilation zone comprises at least one circumferential row of perforations, the ventilation zone can comprise two circumferential rows of perforations. For example, the perforations can be formed on the production line during manufacture of the aerosol-generating article. Preferably, each row of circumferential perforations comprises 8 to 30 perforations.

[0098] The aerosol-generating article according to the application can have a ventilation level of at least about 5%.

[0099] Throughout this specification, the term “ventilation level” is used to mean the volume ratio of the airflow into the aerosol-generating article via the ventilation zone (ventilation airflow) to the sum of the aerosol airflow and the ventilation airflow. The greater the ventilation level, the higher the dilution of the aerosol stream delivered to the consumer.

[0100] The aerosol-generating article can generally have a ventilation level of at least about 10%, preferably at least about 15%, more preferably at least about 20%.

[0101] In preferred embodiments, the aerosol-generating article has a ventilation level of at least about 25%. The aerosol-generating article preferably has a ventilation level of less than about 60%. The aerosol-generating article can have a ventilation level of less than or equal to about 45%. More preferably, the aerosol-generating article has a ventilation level of less than or equal to about 40%, and even more preferably a ventilation level of less than or equal to about 35%.

[0102] In particularly preferred embodiments, the aerosol-generating article has a ventilation level of about 30%. The aerosol-generating article can have a ventilation level of about 20% to about 60%, preferably about 20% to about 45%, more preferably about 20% to about 40%. The aerosol-generating article can have a ventilation level of about 25% to about 60%, preferably about 25% to about 45%, more preferably about 25% to about 40%. In further embodiments, the aerosol-generating article has a ventilation level of about 30% to about 60%, preferably about 30% to about 45%, more preferably about 30% to about 40%.

[0103] In some particularly preferred embodiments, the aerosol-generating article has a ventilation level of about 28% to about 42%. In some particularly preferred embodiments, the aerosol-generating article has a ventilation level of about 30%.

[0104] Embodiments in which the aerosol-generating article comprises a first tubular element downstream of the aerosol-generating substrate and is provided with a ventilation zone at a location along the first tubular element can provide a number of advantages. For example, and without wishing to be bound by theory, the inventors have found that the temperature drop caused by cooler external air entering the first tubular element via the ventilation zone can have a beneficial effect on the nucleation and growth of aerosol particles.

[0105] The formation of aerosols from a gas mixture containing various chemical species depends on subtle interplay between nucleation, evaporation and condensation, while taking into account variations in vapour concentration, temperature and velocity field. The so-called classical nucleation theory is based on the assumption that a fraction of the molecules in the gas phase is large enough to remain coherent for a long time with a certain probability (e.g. half the probability). These molecules represent some kind of critical, threshold molecular cluster in a transient molecular aggregate, which means that on average smaller clusters can quickly dissolve into the gas phase, while larger clusters can on average grow. Such critical clusters are considered to be the key nucleation cores from which droplets are expected to grow due to condensation of molecules from the vapour. It is assumed that the freshly nucleated original droplets appear with a certain original diameter, which can then grow by several orders of magnitude. This process is facilitated and enhanced by rapid cooling of the surrounding vapour. In this regard, it should be kept in mind that evaporation and condensation are two aspects of the same mechanism, namely gas-liquid mass transfer. While evaporation involves net mass transfer from the droplet to the gas phase, condensation is net mass transfer from the gas phase to the droplet phase. Evaporation (or condensation) will shrink (or grow) the droplet, but will not change the number of droplets.

[0106] In this scenario, which can be further complicated by coalescence phenomena, the temperature and rate of cooling play a key role in determining how the system responds. Generally speaking, different cooling rates can lead to significantly different temporal behaviour related to the formation of the liquid phase (droplets), as the nucleation process is often non-linear. Without wishing to be bound by theory, it is assumed that cooling can lead to a rapid increase in the number concentration of droplets, followed by a strong, transient increase in this growth (nucleation burst). This nucleation burst appears to be more pronounced at lower temperatures. Furthermore, it appears that higher cooling rates can favour the onset of nucleation earlier. In contrast, a decrease in the cooling rate appears to have a favourable effect on the final size of the aerosol droplets reached.

[0107] Therefore, the rapid cooling induced by the external air entering the first tubular element via the ventilation zone can advantageously be used to promote the nucleation and growth of aerosol droplets. However, at the same time, the entry of external air into the first tubular element has the direct disadvantage of diluting the aerosol stream delivered to the consumer.

[0108] The inventors have surprisingly found that, when the ventilation level is in the above-mentioned range, the dilution effect on the aerosol, which can be evaluated by measuring in particular the impact on the delivery of aerosol-forming agents, such as glycerol, comprised in the aerosol-generating substrate, is advantageously minimised. In particular, it has been found that a ventilation level between 25% and 50% and even more preferably between 28% and 42% yields particularly satisfactory glycerol delivery values. At the same time, the extent of nucleation and thus the delivery of nicotine and aerosol-forming agents, such as glycerol, is increased.

[0109] The inventors have surprisingly found how the advantageous effects of enhanced nucleation promoted by the rapid cooling caused by the introduction of ventilation air into the article can significantly offset the less desirable dilution effects. Thus, a satisfactory aerosol delivery value is consistently achieved with aerosol-generating articles according to the present disclosure.

[0110] This is particularly advantageous for "short" aerosol-generating articles, for example aerosol-generating articles in which the length of the first element comprising aerosol-generating substrate is less than about 40 millimetres, preferably less than 25 millimetres, even more preferably less than 20 millimetres, or aerosol-generating articles in which the overall length of the aerosol-generating article is less than about 70 millimetres, preferably less than about 60 millimetres, even more preferably less than 50 millimetres. As will be appreciated, in such aerosol-generating articles there is little time and space for the formation of aerosol and the particulate phase of the aerosol to become available for delivery to the consumer.

[0111] Furthermore, because the ventilated first tubular element can be configured to contribute substantially nothing to the overall RTD of the aerosol-generating article, in such aerosol-generating articles the overall RTD of the article can be advantageously fine-tuned by adjusting the length and density of the first element comprising aerosol-generating substrate, or the length and optionally the length and density of the segment of filtration material forming part of the mouthpiece, or the length and density of the element provided upstream of the first element comprising aerosol-generating substrate. Thus, aerosol-generating articles having a predetermined RTD can be consistently and with high precision manufactured, such that a satisfactory level of RTD can be provided to the consumer even in the presence of ventilation.

[0112] Furthermore, the inventors have found that when ventilation is provided into a tubular element having a folded end portion forming a first end wall at a first end of the tubular body, wherein the first end wall bounds an opening for airflow between the cavity of the tubular element and the exterior, an enhanced mixing of hot air from the aerosol-generating substrate with fresh air drawn through the ventilation holes can be achieved. In particular, and without wishing to be bound by theory, it is thought that the partial airflow restriction created by the first end wall in combination with the presence of incoming air from the ventilation can particularly effectively promote the mixing of hot air drawn through the aerosol-forming substrate with fresh air drawn through the ventilation holes.

[0113] The aerosol-generating substrate can further comprise an upstream segment at a position upstream of the aerosol-generating substrate. The upstream segment can comprise one or more upstream elements, for example tubular elements according to the present application. The upstream segment can comprise an upstream element arranged immediately upstream of the aerosol-generating substrate rod. The upstream element can be a tubular element according to the present application, for example the second tubular element described above.

[0114] The first element comprising the aerosol-generating substrate can further comprise a susceptor element located within the aerosol-generating substrate. The susceptor element can be an elongate susceptor element. The susceptor element can extend longitudinally within the aerosol-generating substrate. The susceptor element is configured to be in thermal contact with the aerosol-generating substrate.

[0115] As used herein, the term "susceptor element" refers to a material that can convert electromagnetic energy into heat. When located in a fluctuating electromagnetic field, eddy currents induced in the susceptor element cause the susceptor element to heat up. When an elongate susceptor element is located in thermal contact with the aerosol-generating substrate, the aerosol-generating substrate is heated by the susceptor element.

[0116] The term "elongate" when used to describe a susceptor element means that the length dimension of the susceptor element is greater than its width dimension or its thickness dimension, for example twice as great as its width dimension or its thickness dimension.

[0117] The susceptor element is arranged substantially longitudinally within the rod. This means that the length dimension of the elongate susceptor element is arranged approximately parallel to the longitudinal direction of the rod, for example within plus or minus 10 degrees of the longitudinal direction of the rod. In preferred embodiments, the elongate susceptor element can be located at a radially central position within the rod and extend along the longitudinal axis of the rod.

[0118] Preferably, the susceptor element extends all the way to the downstream end of the first element. The susceptor element can extend all the way to the upstream end of the first element. In particularly preferred embodiments, the susceptor element has substantially the same length as the first element and extends from the upstream end of the first element to the downstream end of the first element.

[0119] The susceptor element is preferably in the form of a pin, rod, ribbon or leaf.

[0120] The susceptor element preferably has a length of from about 5 millimetres to about 15 millimetres, for example from about 6 millimetres to about 12 millimetres, or from about 8 millimetres to about 10 millimetres.

[0121] The ratio of the length of the susceptor element to the overall length of the aerosol- generating article substrate can be from about 0.2 to about 0.35.

[0122] Preferably, the ratio between the length of the susceptor element and the overall length of the aerosol-generating article substrate is at least about 0.22, more preferably at least about 0.24, even more preferably at least about 0.26. The ratio between the length of the susceptor element and the overall length of the aerosol-generating article substrate is preferably less than about 0.34, more preferably less than about 0.32, even more preferably less than about 0.3.

[0123] The ratio between the length of the susceptor element and the overall length of the aerosol- generating article substrate can be from about 0.22 to about 0.34, more preferably from about 0.24 to about 0.34, even more preferably from about 0.26 to about 0.34. The ratio between the length of the susceptor element and the overall length of the aerosol-generating article substrate can be from about 0.22 to about 0.32, more preferably from about 0.24 to about 0.32, even more preferably from about 0.26 to about 0.32. In further embodiments, the ratio between the length of the susceptor element and the overall length of the aerosol-generating article substrate is preferably from about 0.22 to about 0.3, more preferably from about 0.24 to about 0.3, even more preferably from about 0.26 to about 0.3.

[0124] In particularly preferred embodiments, the ratio between the length of the susceptor element and the overall length of the aerosol-generating article substrate is about 0.27.

[0125] The susceptor element preferably has a width of from about 1 millimetre to about 5 millimetres.

[0126] The susceptor element can typically have a thickness of from about 0.01 millimetres to about 2 millimetres, for example from about 0.5 millimetres to about 2 millimetres. The susceptor element can have a thickness of from about 10 micrometres to about 500 micrometres, more preferably from about 10 micrometres to about 100 micrometres.

[0127] If the susceptor element has a constant cross-section, for example a circular cross-section, it has a preferred width or diameter of from about 1 millimetre to about 5 millimetres.

[0128] If the susceptor element has the form of a strip or a leaf, the strip or leaf preferably has a rectangular shape with a width of preferably from about 2 millimetres to about 8 millimetres, more preferably from about 3 millimetres to about 5 millimetres. For example, the susceptor element in the form of a strip or a leaf can have a width of about 4 millimetres.

[0129] If the susceptor element has the form of a strip or a leaf, the strip or leaf preferably has a rectangular shape and a thickness of from about 0.03 millimetres to about 0.15 millimetres, more preferably from about 0.05 millimetres to about 0.09 millimetres. For example, the susceptor element in the form of a strip or a leaf can have a thickness of about 0.07 millimetres.

[0130] In preferred embodiments, the elongate susceptor element is in the form of a strip or a leaf, preferably has a rectangular shape, and has a thickness of from about 55 micrometres to about 65 micrometres.

[0131] More preferably, the elongate susceptor element has a thickness of from about 57 microns to about 63 microns. Even more preferably, the elongate susceptor element has a thickness of from about 58 microns to about 62 microns. In particularly preferred embodiments, the elongate susceptor element has a thickness of about 60 microns.

[0132] Preferably, the elongate susceptor element has a length that is the same as or shorter than the length of the aerosol-generating substrate. Preferably, the elongate susceptor element has the same length as the aerosol-generating substrate.

[0133] The susceptor element can be formed of any material that is capable of being inductively heated to a temperature sufficient to generate an aerosol from the aerosol-generating substrate. Preferably, the susceptor element comprises a metal or carbon.

[0134] Preferably, the susceptor element can comprise or consist of a ferromagnetic material, such as a ferromagnetic alloy, ferritic iron, or a ferromagnetic steel or stainless steel. Suitable susceptor elements can be aluminium or comprise aluminium. Preferably, the susceptor element can be formed of a 400 series stainless steel, such as a 410 grade or 420 grade or 430 grade stainless steel. Different materials will consume different amounts of energy when positioned within an electromagnetic field having similar frequency and field strength values.

[0135] Accordingly, parameters such as the material type, length, width and thickness of the susceptor element can all be altered to achieve a desired power dissipation within a known electromagnetic field. Preferably, the susceptor element can be heated to a temperature in excess of 250 degrees Celsius.

[0136] Suitable susceptor elements can comprise a non-metallic core with a metal layer disposed on the non-metallic core, such as a metal track formed on a surface of a ceramic core. The susceptor element can have an outer protective layer, such as a ceramic protective layer or a glass protective layer encapsulating the susceptor element. The susceptor element can comprise a protective coating of glass, ceramic or inert metal formed on a core of the susceptor element material.

[0137] The susceptor element is arranged in thermal contact with the aerosol-generating substrate. Accordingly, when the susceptor element is heated, the aerosol-generating substrate is heated and an aerosol is formed. Preferably, the susceptor element is arranged in direct physical contact with the aerosol-generating substrate, such as within the aerosol-generating substrate.

[0138] The susceptor element can be a multi-material susceptor element and can comprise a first susceptor element material and a second susceptor element material. The first susceptor element material is arranged in intimate physical contact with the second susceptor element material. The second susceptor element material preferably has a Curie temperature below 500 degrees Celsius. The first susceptor element material is preferably primarily used to heat the susceptor element when the susceptor element is placed in a fluctuating electromagnetic field. Any suitable material can be used. For example, the first susceptor element material can be aluminium, or can be a ferrous material such as stainless steel. The second susceptor element material is preferably primarily used to indicate when the susceptor element has reached a particular temperature, which is the Curie temperature of the second susceptor element material. The Curie temperature of the second susceptor element material can be used to regulate the temperature of the overall susceptor element during operation. Thus, the Curie temperature of the second susceptor element material should be below the ignition point of the aerosol generating substrate. Suitable materials for the second susceptor element material can include nickel and certain nickel alloys.

[0139] By providing a susceptor element having at least a first susceptor element material and a second susceptor element material, where the second susceptor element material has a Curie temperature and the first susceptor element material does not have a Curie temperature, or the first susceptor element material and the second susceptor element material have first and second Curie temperatures that are different from each other, heating of the aerosol generating substrate and temperature control of the heating can be decoupled. The first susceptor element material is preferably a magnetic material having a Curie temperature above 500 degrees Celsius. From a heating efficiency point of view, it is desirable that the Curie temperature of the first susceptor element material is above any maximum temperature that the susceptor element should be able to heat to. The second Curie temperature can preferably be chosen to be below 400 degrees Celsius, preferably below 380 degrees Celsius, or below 360 degrees Celsius. It is preferred that the second susceptor element material is a magnetic material chosen to have a second Curie temperature that is substantially the same as the maximum heating temperature desired. That is, it is preferred that the second Curie temperature is approximately the same as the temperature that the susceptor element should heat to in order to generate an aerosol from the aerosol generating substrate. The second Curie temperature can for example be in the range of 200 degrees Celsius to 400 degrees Celsius, or between 250 degrees Celsius and 360 degrees Celsius. The second Curie temperature of the second susceptor element material can for example be chosen so that the overall average temperature of the aerosol generating substrate does not exceed 240 degrees Celsius after heating by the susceptor element having a temperature equal to the second Curie temperature.

[0140] As mentioned above, the aerosol generating article of the present application comprises a rod of aerosol generating substrate. The aerosol generating substrate can be a solid aerosol generating substrate.

[0141] In certain preferred embodiments, the aerosol generating substrate comprises homogenised plant material, preferably homogenised tobacco material.

[0142] As used herein, the term "homogenised plant material" encompasses any plant material formed from the agglomeration of particles of plant. For example, a sheet or web of homogenised tobacco material for use in the aerosol generating substrate of the application can be formed by coalescing particles of tobacco material obtained by one or more of comminution, milling or crushing plant material, and optionally tobacco lamina and tobacco stems. The homogenised plant material can be produced by casting, extrusion, paper making processes or any other suitable process known in the art.

[0143] The homogenised plant material can be provided in any suitable form. For example, the homogenised plant material can be in the form of one or more sheets. As used herein, the term "sheet" describes a sheet-like element having a width and length substantially greater than its thickness. The homogenised plant material can be in the form of a plurality of pellets or granules. The homogenised plant material can be in the form of a plurality of slivers, strips or shreds. As used herein, the term "sliver" describes an elongate element of material having a length substantially greater than its width and thickness. The term "sliver" should be taken to include strips, shreds and any other homogenised plant material having a similar form. The bundle of homogenised plant material can be formed from a sheet of homogenised plant material, for example by cutting or chopping, or by other methods, for example by an extrusion process.

[0144] The slivers can be formed in situ within the aerosol generating substrate as a result of splitting or breaking of the sheet of homogenised plant material during formation of the aerosol generating substrate, for example as a result of crimping. The slivers of homogenised plant material within the aerosol generating substrate can be separate from one another. At least some of the slivers of homogenised plant material within the aerosol generating substrate can be at least partially connected to an adjacent sliver or slivers along the length of the sliver. For example, adjacent slivers can be connected by one or more fibres. This can occur, for example, in the case of a line of slivers formed as a result of splitting of a sheet of homogenised plant material during production of the aerosol generating substrate, as described above.

[0145] Preferably, the aerosol generating substrate is in the form of one or more sheets of homogenised plant material. The one or more sheets of homogenised plant material can be produced by a casting process. The one or more sheets of homogenised plant material can be produced by a paper making process. The one or more sheets as described herein can each individually have a thickness of between 100 micrometres and 600 micrometres, preferably between 150 micrometres and 300 micrometres, and most preferably between 200 micrometres and 250 micrometres. Individual thickness refers to the thickness of an individual sheet, whereas the combined thickness refers to the total thickness of all sheets making up the aerosol generating substrate. For example, if the aerosol generating substrate is formed from two individual sheets, the combined thickness is the sum of the thicknesses of the two individual sheets or the measured thickness of the two sheets if the two sheets are stacked in the aerosol generating substrate.

[0146] One or more of the sheets as described herein can each individually have a basis weight of about 100 g / m2 2 to about 300 g / m2. 2

[0147] One or more of the sheets as described herein can each individually have a density of about 0.3 g / cm3 3 to about 1.3 g / cm3 3 , preferably about 0.7 g / cm3 3 to about 1.0 g / cm3 3

[0148] In embodiments in which the aerosol generating substrate comprises one or more sheets of homogenised plant material, the sheets are preferably in the form of one or more gathered sheets. As used herein, the term "gathered" means that the sheets of homogenised plant material are rolled, folded or otherwise compressed or contracted substantially transverse to the cylindrical axis of the rod or stick.

[0149] The one or more sheets of homogenised plant material can be gathered transverse to their longitudinal axis and confined with a wrapper to form a continuous stick or rod.

[0150] The one or more sheets of homogenised plant material can advantageously be crimped or similarly treated. As used herein, the term "crimped" means that the sheet has a plurality of substantially parallel ridges or corrugations. Alternatively or in addition to being crimped, the one or more sheets of homogenised plant material can be embossed, debossed, perforated or otherwise deformed to provide a texture on one or both sides of the sheet.

[0151] Preferably, each sheet of homogenised plant material can be crimped such that it has a plurality of ridges or corrugations substantially parallel to the cylindrical axis of the rod. This treatment advantageously facilitates gathering of the crimped sheets of homogenised plant material to form a rod. Preferably, the one or more sheets of homogenised plant material can be gathered. It will be appreciated that the crimped sheets of homogenised plant material can alternatively or additionally have a plurality of substantially parallel ridges or corrugations disposed at an acute or obtuse angle to the cylindrical axis of the rod. The sheets can be crimped to such an extent that the integrity of the sheet is broken at the plurality of parallel ridges or corrugations, causing the material to separate and resulting in the formation of shreds, slivers or ribbons of homogenised plant material.

[0152] ​​One or more sheets of homogenised plant material can be cut into strands as described above. The aerosol generating substrate can comprise a plurality of strands of homogenised plant material. The strands can be used to form a rod. Typically, the strands have a width of about 5 millimetres, or about 4 millimetres, or about 3 millimetres, or about 2 millimetres or less. The strands can have a length of greater than about 5 millimetres, between about 5 millimetres and about 15 millimetres, about 8 millimetres to about 12 millimetres, or about 12 millimetres. Preferably, the strands have substantially the same length as each other. The length of the strands can be determined by the manufacturing process whereby the rod is cut into shorter rods, and the length of the strands corresponds to the length of the rods. The strands can be brittle, which can result in breakage, particularly during transportation. In such cases, the length of some strands can be less than the length of the rods.

[0153] The plurality of strands preferably extend substantially longitudinally along the length of the aerosol generating substrate in alignment with the longitudinal axis. Preferably, the plurality of strands are thus aligned substantially parallel to each other.

[0154] The homogenised plant material can comprise up to about 95% by weight of plant particles on a dry weight basis. Preferably, the homogenised plant material comprises up to about 90% by weight of plant particles on a dry weight basis, more preferably up to about 80% by weight of plant particles, more preferably up to about 70% by weight of plant particles, more preferably up to about 60% by weight of plant particles, more preferably up to about 50% by weight of plant particles on a dry weight basis.

[0155] For example, the homogenised plant material can comprise between about 2.5% and about 95% by weight of plant particles on a dry weight basis, or between about 5% and about 90% by weight of plant particles, or between about 10% and about 80% by weight of plant particles, or between about 15% and about 70% by weight of plant particles, or between about 20% and about 60% by weight of plant particles, or between about 30% and about 50% by weight of plant particles on a dry weight basis.

[0156] The homogenised plant material can be a homogenised tobacco material comprising tobacco particles. The sheet of homogenised tobacco material for use in such embodiments can have a tobacco content of at least about 40% by weight on a dry weight basis, more preferably at least about 50% by weight on a dry weight basis, more preferably at least about 70% by weight on a dry weight basis, and most preferably at least about 90% by weight on a dry weight basis.

[0157] The term "tobacco particles" describes particles of any plant member of the genus Nicotiana. The term "tobacco particles" includes ground or comminuted tobacco leaves, ground or comminuted tobacco lamina, tobacco dust, tobacco fines, and other particulate tobacco by-products formed during the handling, manipulation, and transportation of tobacco. In preferred embodiments, the tobacco particles are derived substantially entirely from tobacco leaves. In contrast, isolated nicotine and nicotine salts are compounds derived from tobacco but are not considered to be tobacco particles for the purposes of the present invention and are not included in the percentage of particulate plant material.

[0158] The tobacco particles can be prepared from one or more tobacco plants. Any type of tobacco can be used in the blend. Examples of tobacco types that can be used include, but are not limited to, sun-cured tobacco, flue-cured tobacco, burley tobacco, Maryland tobacco, Oriental tobacco, Virginia tobacco, and other specialty tobaccos.

[0159] Flue-cured tobacco is a method of curing tobacco, particularly used with Virginia tobacco. During the curing process, heated air is circulated through densely packed tobacco. During the first stage, the leaves turn yellow and wilt. During the second stage, the leaves are fully dried. In the third stage, the stems are fully dried.

[0160] Burley tobacco plays an important role in many tobacco blends. Burley tobacco has a distinctive flavor and aroma and also has the ability to absorb a large amount of casing.

[0161] Oriental tobacco is a type of tobacco that has small leaves and a high aromatic quality. However, the flavor of Oriental tobacco is milder than, for example, the flavor of burley tobacco. Therefore, a relatively small proportion of Oriental tobacco is typically used in tobacco blends.

[0162] Kasturi, Madura, and Jatim are all subtypes of sun-cured tobacco that can be used. Preferably, Kasturi tobacco and flue-cured tobacco can be used in the blend to produce the tobacco particles. Thus, the tobacco particles in the particulate plant material can include a mixture of Kasturi tobacco and flue-cured tobacco.

[0163] The tobacco particles can have a nicotine content of at least about 2.5% by weight on a dry weight basis. More preferably, the tobacco particles can have a nicotine content of at least about 3% by weight on a dry weight basis, even more preferably at least about 3.2% by weight, even more preferably at least about 3.5% by weight, most preferably at least about 4% by weight.

[0164] The homogenised plant material can comprise a combination of tobacco particles and non-tobacco plant flavour particles. Preferably, the non-tobacco plant flavour particles are selected from one or more of: ginger particles, rosemary particles, eucalyptus particles, clove particles and star anise particles. Preferably, in such embodiments, the homogenised plant material comprises at least about 2.5% by weight of non-tobacco plant flavour particles on a dry weight basis, with the remainder of the plant particles being tobacco particles. Preferably, the homogenised plant material comprises at least about 4% by weight of non-tobacco plant flavour particles on a dry weight basis, more preferably at least about 6% by weight of non-tobacco plant flavour particles, more preferably at least about 8% by weight of non-tobacco plant flavour particles, and more preferably at least about 10% by weight of non-tobacco plant flavour particles. Preferably, the homogenised plant material comprises at most about 20% by weight of non-tobacco plant flavour particles, more preferably at most about 18% by weight of non-tobacco plant flavour particles, more preferably at most about 16% by weight of non-tobacco plant flavour particles.

[0165] The weight ratio of non-tobacco plant flavour particles to tobacco particles in the particulate plant material forming the homogenised plant material can vary depending on the desired flavour profile and composition of the aerosol generated from the aerosol generating substrate during use. Preferably, the homogenised plant material comprises at least a 1 :30 weight ratio of non-tobacco plant flavour particles to tobacco particles on a dry weight basis, more preferably at least a 1 :20 weight ratio of non-tobacco plant flavour particles to tobacco particles, more preferably at least a 1 : 10 weight ratio of non-tobacco plant flavour particles to tobacco particles, and most preferably at least a 1 :5 weight ratio of non-tobacco plant flavour particles to tobacco particles.

[0166] The homogenised plant material preferably comprises no more than 95% by weight of particulate plant material on a dry weight basis. Thus, the particulate plant material is typically combined with one or more other components to form the homogenised plant material.

[0167] The homogenised plant material can also comprise a binder to alter the mechanical properties of the particulate plant material, wherein the binder is included in the homogenised plant material during manufacture as described herein. Suitable extrinsic binders are known to those skilled in the art and include, but are not limited to: gums, such as guar gum, xanthan gum, gum arabic and locust bean gum; cellulosic binders, such as hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose and ethyl cellulose; polysaccharides, such as starch; organic acids, such as alginic acid; conjugate base salts of organic acids, such as sodium alginate, agar and pectin; and combinations thereof. Preferably, the binder comprises guar gum.

[0168] The binder can be present in an amount of from about 1% to about 10% by weight based on the dry weight of the homogenised plant material, preferably in an amount of from about 2% to about 5% by weight based on the dry weight of the homogenised plant material.

[0169] The homogenized plant material can further include one or more lipids to facilitate diffusion of volatile components (e.g., aerosol formers, capsaicin, and nicotine), wherein the lipids are included in the homogenized plant material during manufacture as described herein. Suitable lipids for inclusion in the homogenized plant material include, but are not limited to: medium chain triglycerides, cocoa butter, palm oil, palm kernel oil, mango oil, shea oil, soybean oil, cottonseed oil, coconut oil, hydrogenated coconut oil, candelilla wax, carnauba wax, shellac, sunflower wax, sunflower oil, rice bran, and Revel A; and combinations thereof.

[0170] The homogenized plant material can further include a pH modifier.

[0171] The homogenized plant material can further include fibers to alter the mechanical properties of the homogenized plant material, wherein the fibers are included in the homogenized plant material during manufacture as described herein. Suitable exogenous fibers for inclusion in the homogenized plant material are known in the art and include fibers formed from non-tobacco materials and non-ginger materials, including but not limited to: cellulose fibers; softwood fibers; hardwood fibers; and combinations thereof. Exogenous fibers derived from tobacco and / or ginger can also be added. Any fibers added to the homogenized plant material are not considered to form part of the "particulate plant material" as defined above. The fibers can be treated by suitable methods known in the art prior to inclusion in the homogenized plant material, including but not limited to: mechanical pulping; refining; chemical pulping; bleaching; kraft pulping; and combinations thereof. The fibers generally have a length greater than their width.

[0172] Suitable fibers generally have a length greater than 400 microns and less than or equal to 4 millimeters, preferably in the range of 0.7 millimeters to 4 millimeters. Preferably, the fibers are present in an amount of about 2 wt% to about 15 wt%, most preferably about 4 wt%, based on the dry weight of the substrate.

[0173] The homogenized plant material can further include one or more aerosol formers. Upon volatilization, the aerosol formers can transport other volatilized compounds such as nicotine and flavorants released from the aerosol-generating substrate upon heating in an aerosol. Suitable aerosol formers for inclusion in the homogenized plant material are known in the art and include, but are not limited to: polyhydric alcohols such as triethylene glycol, 1,3-butanediol, and glycerol; esters of polyhydric alcohols such as glycerol mono-, di-, or triacetate; and aliphatic esters of mono-, di-, or poly-carboxylic acids such as dimethyl dodecanedioate and dimethyl tetradecanedioate.

[0174] The homogenised plant material can have an aerosol former content of between about 5% and about 30% by weight on a dry weight basis, for example between about 10% and about 25% by weight on a dry weight basis, or between about 15% and about 20% by weight on a dry weight basis.

[0175] For example, if the substrate is intended for use in an aerosol-generating article for an electrically operated aerosol-generating system having a heating element, it can preferably comprise an aerosol former content of between about 5% and about 30% by weight on a dry weight basis. If the substrate is intended for use in an aerosol-generating article for an electrically operated aerosol-generating system having a heating element, the aerosol former is preferably glycerol.

[0176] The homogenised plant material can have an aerosol former content of between about 1% and about 5% by weight on a dry weight basis. For example, if the substrate is intended for use in an aerosol-generating article in which the aerosol former is held in a reservoir separate from the substrate, the substrate can have an aerosol former content of greater than 1% and less than about 5%. In such embodiments, the aerosol former volatilises on heating and a stream of aerosol former contacts the aerosol-generating substrate in order to entrain flavour from the aerosol-generating substrate in the aerosol.

[0177] The homogenised plant material can have an aerosol former content of between about 30% and about 45% by weight. This relatively high level of aerosol former is particularly suitable for aerosol-generating substrates which are intended to be heated at a temperature of less than 275 degrees Celsius. In such embodiments, the homogenised plant material preferably further comprises between about 2% and about 10% by weight on a dry weight basis of a cellulose ether and between about 5% and about 50% by weight on a dry weight basis of additional cellulose. The use of a combination of cellulose ether and additional cellulose has been found to provide particularly effective aerosol delivery when used in an aerosol-generating substrate having an aerosol former content of between 30% and 45% by weight.

[0178] Suitable cellulose ethers include, but are not limited to, methyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, ethyl hydroxyethyl cellulose and carboxymethyl cellulose (CMC). In particularly preferred embodiments, the cellulose ether is carboxymethyl cellulose.

[0179] As used herein, the term "additional cellulose" encompasses any cellulose material that is incorporated into the homogenized plant material that does not originate from the non-tobacco plant particles or tobacco particles provided in the homogenized plant material. Thus, in addition to the non-tobacco plant material or tobacco material, the additional cellulose is incorporated into the homogenized plant material as a separate and distinct source of cellulose from any cellulose inherently provided within the non-tobacco plant particles or tobacco particles. The additional cellulose is typically derived from a different plant than the non-tobacco plant particles or tobacco particles. Preferably, the additional cellulose is in the form of an inert cellulose material that is sensorially inert and thus does not substantially affect the organoleptic properties of the aerosol generated by the aerosol generating substrate. For example, the additional cellulose is preferably a tasteless and odorless material.

[0180] The additional cellulose can comprise cellulose powder, cellulose fibers, or a combination thereof.

[0181] The aerosol former can act as a humectant in the aerosol generating substrate.

[0182] The wrapper defining the homogenized plant material rod can be a paper wrapper or a non-paper wrapper. Suitable paper wrappers for use in particular embodiments of the present application are known in the art and include, but are not limited to: cigarette paper; and filter plug wrap. Suitable non-paper wrappers for use in particular embodiments of the present application are known in the art and include, but are not limited to, sheets of homogenized tobacco material. In certain preferred embodiments, the wrapper can be formed from a laminate comprising a plurality of layers. Preferably, the wrapper is formed from an aluminum co-laminate sheet. The use of a co-laminate sheet comprising aluminum advantageously prevents combustion of the aerosol generating substrate in the event that the aerosol generating substrate is intended to be ignited rather than heated in the intended manner.

[0183] In some preferred embodiments, the aerosol generating substrate comprises a gel composition comprising an alkaloid compound. In particularly preferred embodiments, the aerosol generating substrate comprises a gel composition comprising nicotine.

[0184] Preferably, the gel composition comprises an alkaloid compound; an aerosol former; and at least one gelling agent. Preferably, the at least one gelling agent forms a solid medium and the glycerol is dispersed in the solid medium, wherein the alkaloid is dispersed in the glycerol. Preferably, the gel composition is a stable gel phase.

[0185] Advantageously, the stable gel composition including nicotine provides a predictable composition form upon storage or shipping from the manufacturer to the consumer. The stable gel composition including nicotine substantially maintains its shape. The stable gel composition including nicotine does not substantially release a liquid phase upon storage or shipping from the manufacturer to the consumer. The stable gel composition including nicotine can provide a simple consumable design. The consumable can not have to be designed to contain a liquid, thus a wider range of materials and container configurations can be considered.

[0186] The gel composition described herein can be combined with an aerosol-generating device to provide a nicotine aerosol to the lungs at an inhalation rate or airflow rate in the range of conventional smoking mode inhalation rates or airflow rates. The aerosol-generating device can continuously heat the gel composition. The consumer can take multiple inhalations or “puffs,” with each “puff” delivering an amount of nicotine aerosol. When heated, preferably in a continuous manner, the gel composition is capable of delivering a high nicotine / low total particulate matter (TPM) aerosol to the consumer.

[0187] The phrase “stable gel phase” or “stable gel” refers to a gel that substantially maintains its shape and mass when exposed to various environmental conditions. A stable gel can not substantially release (sweat) or absorb moisture when exposed to standard temperature and pressure while the relative humidity is changed from about 10% to about 60%. For example, a stable gel can substantially maintain its shape and mass when exposed to standard temperature and pressure while the relative humidity is changed from about 10% to about 60%.

[0188] The gel composition can include an alkaloid compound. The gel composition can include one or more alkaloids.

[0189] The term “alkaloid compound” refers to any one of a class of naturally occurring organic compounds that contain one or more basic nitrogen atoms. Typically, alkaloids contain at least one nitrogen atom in an amine-type structure. This or another nitrogen atom in the molecule of an alkaloid compound can act as a base in an acid-base reaction. One or more of the nitrogen atoms of most alkaloid compounds are part of a cyclic system, such as a heterocycle. In nature, alkaloid compounds are found primarily in plants, especially in certain families of flowering plants. However, some alkaloid compounds are found in animal species and fungi. In the present disclosure, the term “alkaloid compound” refers to both naturally sourced alkaloid compounds and synthetically manufactured alkaloid compounds.

[0190] The gel composition can preferably include an alkaloid compound selected from the group consisting of nicotine, anatabine, and combinations thereof.

[0191] Preferably, the gel composition includes nicotine.

[0192] The term "nicotine" refers to nicotine and nicotine derivatives, such as free base nicotine, nicotine salts, and the like.

[0193] The gel composition can contain nicotine.

[0194] The gel composition preferably includes about 0.5% to about 10% by weight of the alkaloid compound. The gel composition can include about 0.5% to about 5% by weight of the alkaloid compound. Preferably, the gel composition includes about 1% to about 3% by weight of the alkaloid compound. The gel composition can preferably include about 1.5% to about 2.5% by weight of the alkaloid compound. The gel composition can preferably include about 2% by weight of the alkaloid compound. The alkaloid compound component of the gel formulation can be the most volatile component in the gel formulation. In some aspects, water can be the most volatile component in the gel formulation, and the alkaloid compound component of the gel formulation can be the second most volatile component in the gel formulation. In some aspects, water can be the most volatile component in the gel formulation, and the alkaloid compound component of the gel formulation can be the second most volatile component in the gel formulation.

[0195] Preferably, the gel composition contains nicotine. Nicotine can be added to the composition in free base form or salt form. The gel composition includes about 0.5% to about 10% by weight of the nicotine, or about 0.5% to about 5% by weight of the nicotine. Preferably, the gel composition includes about 1% to about 3% by weight of the nicotine, or about 1.5% to about 2.5% by weight of the nicotine, or about 2% by weight of the nicotine. The nicotine component of the gel formulation can be the most volatile component in the gel formulation. In some aspects, water can be the most volatile component in the gel formulation, and the nicotine component of the gel formulation can be the second most volatile component in the gel formulation.

[0196] The gel composition preferably includes an aerosol former. Ideally, the aerosol former is substantially resistant to thermal degradation at the operating temperature of the associated aerosol-generating device. Suitable aerosol formers include, but are not limited to, polyhydric alcohols such as triethylene glycol, 1,3-butanediol, and glycerol; esters of polyhydric alcohols such as glycerol mono-, di-, or triacetate; and aliphatic esters of mono-, di-, or polycarboxylic acids such as dimethyl dodecanedioate and dimethyl tetradecanedioate. The polyhydric alcohol or mixture thereof can be one or more of triethylene glycol, 1,3-butanediol, glycerol (glycerin or propane-1,2,3-triol), or polyethylene glycol. The aerosol former is preferably glycerol.

[0197] The gel composition can include a majority of the aerosol former. The gel composition can include a mixture of water and aerosol former, wherein the aerosol former forms a majority (by weight) of the gel composition. The aerosol former can form at least about 50% by weight of the gel composition. The aerosol former can form at least about 60% by weight or at least about 65% by weight or at least about 70% by weight of the gel composition. The aerosol former can form about 70% to about 80% by weight of the gel composition. The aerosol former can form about 70% to about 75% by weight of the gel composition.

[0198] The gel composition can include a majority of glycerol. The gel composition can include a mixture of water and glycerol, wherein the glycerol forms a majority (by weight) of the gel composition. The glycerol can form at least about 50% by weight of the gel composition. The glycerol can form at least about 60% by weight or at least about 65% by weight or at least about 70% by weight of the gel composition. The glycerol can form about 70% to about 80% by weight of the gel composition. The glycerol can form about 70% to about 75% by weight of the gel composition.

[0199] The gel composition preferably includes at least one gelling agent. Preferably, the gel composition includes a gelling agent in a total amount in the range of about 0.4% to about 10% by weight. More preferably, the composition includes a gelling agent in the range of about 0.5% to about 8% by weight. More preferably, the composition includes a gelling agent in the range of about 1% to about 6% by weight. More preferably, the composition includes a gelling agent in the range of about 2% to about 4% by weight. More preferably, the composition includes a gelling agent in the range of about 2% to about 3% by weight.

[0200] The term "gelling agent" refers to a compound that, when added in an amount of about 0.3% by weight to a mixture of 50% by weight water / 50% by weight glycerol, uniformly forms a solid medium or supporting matrix that results in a gel. Gelling agents include, but are not limited to, hydrogen-bond crosslinking gelling agents and ionically crosslinking gelling agents.

[0201] The gelling agent can include one or more biopolymers. The biopolymers can be formed from polysaccharides.

[0202] Biopolymers include, for example, gellan gum (natural, low acyl gellan gum, high acyl gellan gum, preferably low acyl gellan gum), xanthan gum, alginate (alginic acid), agar, guar gum, and the like. The composition can preferably include xanthan gum. The composition can include two biopolymers. The composition can include three biopolymers. The composition can include two biopolymers in substantially equal amounts by weight. The composition can include three biopolymers in substantially equal amounts by weight.

[0203] Preferably, the gel composition includes at least about 0.2% by weight of a hydrogen bond cross-linking gelling agent. The gel composition preferably includes at least about 0.2% by weight of an ionically cross-linking gelling agent. Most preferably, the gel composition includes at least about 0.2% by weight of a hydrogen bond cross-linking gelling agent and at least about 0.2% by weight of an ionically cross-linking gelling agent. The gel composition can include from about 0.5% to about 3% by weight of a hydrogen bond cross-linking gelling agent and from about 0.5% to about 3% by weight of an ionically cross-linking gelling agent, or from about 1% to about 2% by weight of a hydrogen bond cross-linking gelling agent and from about 1% to about 2% by weight of an ionically cross-linking gelling agent. The hydrogen bond cross-linking gelling agent and the ionically cross-linking gelling agent can be present in the gel composition in substantially equal amounts by weight.

[0204] The term "hydrogen bond cross-linking gelling agent" refers to a gelling agent that forms non-covalent cross-linking bonds or physical cross-linking bonds via hydrogen bonds. A hydrogen bond is an electrostatic dipole-dipole attraction type between molecules, rather than a covalent bond with a hydrogen atom. It is created by an attractive force between a hydrogen atom covalently bonded to a highly electronegative atom, such as an N, O, or F atom, and another highly electronegative atom.

[0205] The hydrogen bond cross-linking gelling agent can include one or more of a galactomannan, a gelatin, an agarose, or a konjac gum or agar. The hydrogen bond cross-linking gelling agent can preferably include agar.

[0206] The gel composition preferably includes a hydrogen bond cross-linking gelling agent in a range of from about 0.3% to about 5% by weight. Preferably, the composition includes a hydrogen bond cross-linking gelling agent in a range of from about 0.5% to about 3% by weight. Preferably, the composition includes a hydrogen bond cross-linking gelling agent in a range of from about 1% to about 2% by weight.

[0207] The gel composition can include a galactomannan in a range of from about 0.2% to about 5% by weight. Preferably, the galactomannan can be in a range of from about 0.5% to about 3% by weight. Preferably, the galactomannan can be in a range of from about 0.5% to about 2% by weight. Preferably, the galactomannan can be in a range of from about 1% to about 2% by weight.

[0208] The gel composition can include a gelatin in a range of from about 0.2% to about 5% by weight. Preferably, the gelatin can be in a range of from about 0.5% to about 3% by weight. Preferably, the gelatin can be in a range of from about 0.5% to about 2% by weight. Preferably, the gelatin can be in a range of from about 1% to about 2% by weight.

[0209] The gel composition can include an agarose in a range of from about 0.2% to about 5% by weight. Preferably, the agarose can be in a range of from about 0.5% to about 3% by weight. Preferably, the agarose can be in a range of from about 0.5% to about 2% by weight. Preferably, the agarose can be in a range of from about 1% to about 2% by weight.

[0210] The gel composition can include konjac gum in a range of about 0.2 wt% to about 5 wt%. Preferably, the konjac gum can be in a range of about 0.5 wt% to about 3 wt%. Preferably, the konjac gum can be in a range of about 0.5 wt% to about 2 wt%. Preferably, the konjac gum can be in a range of about 1 wt% to about 2 wt%.

[0211] The gel composition can include agar in a range of about 0.2 wt% to about 5 wt%. Preferably, the agar can be in a range of about 0.5 wt% to about 3 wt%. Preferably, the agar can be in a range of about 0.5 wt% to about 2 wt%. Preferably, the agar can be in a range of about 1 wt% to about 2 wt%.

[0212] The term“ionically crosslinking gelling agent” refers to a gelling agent that forms non-covalent crosslinks or physical crosslinks through ionic bonds. Ionic crosslinking involves the association of polymer chains through non-covalent interactions. A crosslinked network is formed when oppositely charged multivalent molecules electrostatically attract each other to form a crosslinked polymer network.

[0213] The ionically crosslinking gelling agent can include low acyl gellan gum, pectin, kappa-carrageenan, iota-carrageenan, or alginate. The ionically crosslinking gelling agent can preferably include low acyl gellan gum.

[0214] The gel composition can include an ionically crosslinking gelling agent in a range of about 0.3 wt% to about 5 wt%. Preferably, the composition includes an ionically crosslinking gelling agent in a range of about 0.5 wt% to about 3 wt%. Preferably, the composition includes an ionically crosslinking gelling agent in a range of about 1 wt% to about 2 wt%.

[0215] The gel composition can include low acyl gellan gum in a range of about 0.2 wt% to about 5 wt%. Preferably, the low acyl gellan gum can be in a range of about 0.5 wt% to about 3 wt%. Preferably, the low acyl gellan gum can be in a range of about 0.5 wt% to about 2 wt%. Preferably, the low acyl gellan gum can be in a range of about 1 wt% to about 2 wt%.

[0216] The gel composition can include pectin in a range of about 0.2 wt% to about 5 wt%. Preferably, the pectin can be in a range of about 0.5 wt% to about 3 wt%. Preferably, the pectin can be in a range of about 0.5 wt% to about 2 wt%. Preferably, the pectin can be in a range of about 1 wt% to about 2 wt%.

[0217] The gel composition can include kappa-carrageenan in a range of about 0.2 wt% to about 5 wt%. Preferably, the kappa-carrageenan can be in a range of about 0.5 wt% to about 3 wt%. Preferably, the kappa-carrageenan can be in a range of about 0.5 wt% to about 2 wt%. Preferably, the kappa-carrageenan can be in a range of about 1 wt% to about 2 wt%.

[0218] The gel composition can include iota-carrageenan in a range of about 0.2 wt% to about 5 wt%. Preferably, the iota-carrageenan can be in a range of about 0.5 wt% to about 3 wt%. Preferably, the iota-carrageenan can be in a range of about 0.5 wt% to about 2 wt%. Preferably, the iota-carrageenan can be in a range of about 1 wt% to about 2 wt%.

[0219] The gel composition can include alginate in a range of about 0.2 wt% to about 5 wt%. Preferably, the alginate can be in a range of about 0.5 wt% to about 3 wt%. Preferably, the alginate can be in a range of about 0.5 wt% to about 2 wt%. Preferably, the alginate can be in a range of about 1 wt% to about 2 wt%.

[0220] The gel composition can include the hydrogen-bond crosslinking gelling agent and the ionic crosslinking gelling agent in a ratio of about 3: 1 to about 1 :3. Preferably, the gel composition can include the hydrogen-bond crosslinking gelling agent and the ionic crosslinking gelling agent in a ratio of about 2: 1 to about 1 :2. Preferably, the gel composition can include the hydrogen-bond crosslinking gelling agent and the ionic crosslinking gelling agent in a ratio of about 1 : 1.

[0221] The gel composition can further include a viscosity enhancing agent. The viscosity enhancing agent in combination with the hydrogen-bond crosslinking gelling agent and the ionic crosslinking gelling agent appears to unexpectedly support the solid medium and maintain the gel composition even when the gel composition includes high levels of glycerol.

[0222] The term "viscosity enhancing agent" refers to a compound that increases the viscosity without causing the mixture to form a gel, remain or retain fluid when homogenously added in an amount of 0.3 wt% to a mixture of 50 wt% water / 50 wt% glycerol at 25°C. Preferably, the viscosity enhancing agent refers to a compound that increases the viscosity to at least 50 cPs, preferably at least 200 cPs, preferably at least 500 cPs, preferably at least 1000 cPs, without causing the mixture to form a gel, remain or retain fluid when homogenously added in an amount of 0.3 wt% to a mixture of 50 wt% water / 50 wt% glycerol at 25°C at a shear rate of 0.1 s -1 -1 ​a shear rate that increases the viscosity to at least 2-fold, or at least 5-fold, or at least 10-fold, or at least 100-fold of the viscosity before the addition, without causing gel formation, the mixture remains or retains fluidity.

[0223] Viscosity values described herein can be measured using a Brookfield RVT viscometer with a spindle RV#2 disc rotating at 6 revolutions per minute (rpm) at 25 °C.

[0224] The gel composition preferably includes a viscosity increasing agent in a range of about 0.2 wt% to about 5 wt%. Preferably, the composition includes a viscosity increasing agent in a range of about 0.5 wt% to about 3 wt%. Preferably, the composition includes a viscosity increasing agent in a range of about 0.5 wt% to about 2 wt%. Preferably, the composition includes a viscosity increasing agent in a range of about 1 wt% to about 2 wt%.

[0225] The viscosity increasing agent can include one or more of xanthan gum, carboxymethyl cellulose, microcrystalline cellulose, methyl cellulose, gum arabic, guar gum, lambda carrageenan, or starch. The viscosity increasing agent can preferably include xanthan gum.

[0226] The gel composition can include xanthan gum in a range of about 0.2 wt% to about 5 wt%. Preferably, the xanthan gum can be in a range of about 0.5 wt% to about 3 wt%. Preferably, the xanthan gum can be in a range of about 0.5 wt% to about 2 wt%. Preferably, the xanthan gum can be in a range of about 1 wt% to about 2 wt%.

[0227] The gel composition can include carboxymethyl cellulose in a range of about 0.2 wt% to about 5 wt%. Preferably, the carboxymethyl cellulose can be in a range of about 0.5 wt% to about 3 wt%. Preferably, the carboxymethyl cellulose can be in a range of about 0.5 wt% to about 2 wt%. Preferably, the carboxymethyl cellulose can be in a range of about 1 wt% to about 2 wt%.

[0228] The gel composition can include microcrystalline cellulose in a range of about 0.2 wt% to about 5 wt%. Preferably, the microcrystalline cellulose can be in a range of about 0.5 wt% to about 3 wt%. Preferably, the microcrystalline cellulose can be in a range of about 0.5 wt% to about 2 wt%. Preferably, the microcrystalline cellulose can be in a range of about 1 wt% to about 2 wt%.

[0229] The gel composition can include methyl cellulose in a range of about 0.2 wt% to about 5 wt%. Preferably, the methyl cellulose can be in a range of about 0.5 wt% to about 3 wt%. Preferably, the methyl cellulose can be in a range of about 0.5 wt% to about 2 wt%. Preferably, the methyl cellulose can be in a range of about 1 wt% to about 2 wt%.

[0230] The gel composition can include gum arabic in a range of about 0.2 wt% to about 5 wt%. Preferably, gum arabic can be in a range of about 0.5 wt% to about 3 wt%. Preferably, gum arabic can be in a range of about 0.5 wt% to about 2 wt%. Preferably, gum arabic can be in a range of about 1 wt% to about 2 wt%.

[0231] The gel composition can include guar gum in a range of about 0.2 wt% to about 5 wt%. Preferably, guar gum can be in a range of about 0.5 wt% to about 3 wt%. Preferably, guar gum can be in a range of about 0.5 wt% to about 2 wt%. Preferably, guar gum can be in a range of about 1 wt% to about 2 wt%.

[0232] The gel composition can include lambda carrageenan in a range of about 0.2 wt% to about 5 wt%. Preferably, lambda carrageenan can be in a range of about 0.5 wt% to about 3 wt%. Preferably, lambda carrageenan can be in a range of about 0.5 wt% to about 2 wt%. Preferably, lambda carrageenan can be in a range of about 1 wt% to about 2 wt%.

[0233] The gel composition can include starch in a range of about 0.2 wt% to about 5 wt%. Preferably, starch can be in a range of about 0.5 wt% to about 3 wt%. Preferably, starch can be in a range of about 0.5 wt% to about 2 wt%. Preferably, starch can be in a range of about 1 wt% to about 2 wt%.

[0234] The gel composition can further include a divalent cation. Preferably, the divalent cation includes a calcium ion, such as calcium lactate in solution. For example, the divalent cation, such as calcium ion, can help form a gel of the composition including a gelling agent, such as an ionically crosslinked gelling agent. The ionic effect can help gel formation. The divalent cation can be present in the gel composition in a range of about 0.1 wt% to about 1 wt% or about 0.5 wt%.

[0235] The gel composition can further include an acid. The acid can include a carboxylic acid. The carboxylic acid can include a ketone group. Preferably, the carboxylic acid can include a ketone group having less than about 10 carbon atoms or less than about 6 carbon atoms or less than about 4 carbon atoms, such as levulinic acid or lactic acid. Preferably, the carboxylic acid has three carbon atoms, such as lactic acid. Lactic acid surprisingly improves the stability of the gel composition even more than similar carboxylic acids. The carboxylic acid can help gel formation. During storage, the carboxylic acid can reduce changes in the concentration of the alkaloid compound in the gel composition. During storage, the carboxylic acid can reduce changes in the concentration of nicotine in the gel composition.

[0236] The gel composition can include carboxylic acid in a range of about 0.1 wt% to about 5 wt%. Preferably, the carboxylic acid can be in a range of about 0.5 wt% to about 3 wt%. Preferably, the carboxylic acid can be in a range of about 0.5 wt% to about 2 wt%. Preferably, the carboxylic acid can be in a range of about 1 wt% to about 2 wt%.

[0237] The gel composition can include lactic acid in a range of about 0.1 wt% to about 5 wt%. Preferably, the lactic acid can be in a range of about 0.5 wt% to about 3 wt%. Preferably, the lactic acid can be in a range of about 0.5 wt% to about 2 wt%. Preferably, the lactic acid can be in a range of about 1 wt% to about 2 wt%.

[0238] The gel composition can include levulinic acid in a range of about 0.1 wt% to about 5 wt%. Preferably, the levulinic acid can be in a range of about 0.5 wt% to about 3 wt%. Preferably, the levulinic acid can be in a range of about 0.5 wt% to about 2 wt%. Preferably, the levulinic acid can be in a range of about 1 wt% to about 2 wt%.

[0239] The gel composition preferably includes some water. When the gel composition includes some water, the gel composition is more stable. Preferably, the gel composition includes at least about 1 wt%, or at least about 2 wt%, or at least about 5 wt% water. Preferably, the gel composition includes at least about 10 wt% or at least about 15 wt% water.

[0240] Preferably, the gel composition includes between about 8 wt% and 32 wt% water. Preferably, the gel composition includes about 15 wt% to about 25 wt% water. Preferably, the gel composition includes about 18 wt% to about 22 wt% water. Preferably, the gel composition includes about 20 wt% water.

[0241] Preferably, the aerosol-generating substrate includes between about 150 mg and about 350 mg of the gel composition.

[0242] Preferably, in embodiments comprising the gel composition, the aerosol-generating substrate comprises a porous medium loaded with the gel composition. The advantage of a porous medium loaded with the gel composition is that the gel composition is retained within the porous medium and this can aid in the manufacture, storage or transportation of the gel composition. It can help to maintain the desired shape of the gel composition, particularly during manufacture, transportation or use.

[0243] The term “porous” is used herein to refer to a material that provides a plurality of pores or openings that allow air to pass through the material.

[0244] The porous medium can be any suitable porous material capable of holding or retaining the gel composition. Desirably, the porous medium can allow the gel composition to move within it. In particular embodiments, the porous medium comprises a natural material, a synthetic or semi-synthetic material, or a combination thereof. In particular embodiments, the porous medium comprises a sheet material, a foam, or a fiber, such as a loose fiber; or a combination thereof. In particular embodiments, the porous medium comprises a woven, nonwoven, or extruded material, or a combination thereof. Preferably, the porous medium comprises cotton, paper, viscose, PLA, or cellulose acetate, or a combination thereof. Preferably, the porous medium comprises a sheet material, such as cotton or cellulose acetate. In particularly preferred embodiments, the porous medium comprises a sheet made of cotton fibers.

[0245] The porous medium can be crimped or shredded. In preferred embodiments, the porous medium is crimped. In alternative embodiments, the porous medium comprises shredded porous medium. The crimping or shredding process can be performed before or after loading the gel composition.

[0246] Crimping the sheet has the benefit of improving the structure to allow for passage through the structure. Channels through the crimped sheet material facilitate loading of the gel, holding of the gel, and also facilitate passage of fluid through the crimped sheet material. Thus, there are advantages to using a crimped sheet material as the porous medium.

[0247] Shredding enables easy absorption of the gel by the high surface area to volume ratio of the culture medium.

[0248] In some embodiments, the sheet is a composite material. Preferably, the sheet is porous. The sheet can aid in manufacturing the tubular element comprising the gel. The sheet can aid in introducing the active agent into the tubular element comprising the gel. The sheet can aid in stabilizing the structure of the tubular element comprising the gel. The sheet can aid in transporting or storing the gel. Using the sheet can enable or aid in adding structure to the porous medium, such as by crimping the sheet.

[0249] The porous medium can be a thread. The thread can comprise, for example, cotton, paper, or acetate silk. The thread can also be loaded with gel, as any other porous medium. An advantage of using a thread as the porous medium is that it can aid in ease of manufacture.

[0250] The thread can be loaded with gel by any known means. The thread can simply be coated with gel, or the thread can be impregnated with gel. In manufacture, the thread can be impregnated with gel and stored ready for inclusion in the assembly of the tubular element.

[0251] Preferably, in embodiments wherein the first element comprises a gel composition as described above, the downstream section of the aerosol-generating article comprises a first tubular element according to the application, wherein the first tubular element has a length of less than 10 millimetres. The use of such a relatively short tubular element in combination with a gel composition can optimise the delivery of aerosol to the consumer.

[0252] Embodiments of the application wherein the aerosol-generating substrate comprises a gel composition as described above preferably comprise an upstream element upstream of the first element comprising the aerosol-generating substrate. In this case, the upstream element advantageously prevents physical contact with the gel composition. The upstream element can also advantageously compensate for any potential reduction in RTD, for example due to evaporation of the gel composition upon heating of the first element comprising the aerosol-generating substrate during use.

[0253] Features described in relation to one embodiment or implementation can also be applicable to other embodiments and implementations.

[0254] A non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples can be combined with any one or more features of another example, implementation or aspect described herein.

[0255] EX1. A tubular element for an aerosol-generating article, the tubular element comprising: a tubular body defining a lumen extending from a first end of the tubular body to a second end of the tubular body; a folded end portion forming a first end wall at the first end of the tubular body, the first end wall delimiting an opening for airflow between the lumen of the tubular element and the exterior; and a ventilation zone at a location along the tubular body of the tubular element.

[0256] EX2. The tubular element according to EX1, wherein the ventilation zone comprises a plurality of perforations through the tubular body.

[0257] EX3. The tubular element according to EX1 or EX2, wherein the ventilation zone is located between about 5 millimetres and about 15 millimetres from the folded end portion of the tubular element.

[0258] EX4. The tubular element according to any one of EX1 to EX3, wherein the ventilation zone comprises at least one circumferential row of perforations extending around the tubular body.

[0259] EX5. The tubular element according to any one of EX1 to EX4, wherein the tubular element has a ventilation level of about 20% to about 70%.

[0260] EX6. The tubular element according to any one of EX1 to EX5, wherein the tubular element is formed of a paper material.

[0261] EX7. The tubular element according to any of EX1 to EX6, wherein at least a first portion of the tubular element forming the first end wall is air impermeable.

[0262] EX8. The tubular element according to any of EX1 to EX7, wherein the first end wall extends partially into the lumen of the tubular body and forms an angle of less than 90 degrees with the inner surface of the tubular body.

[0263] EX9. An aerosol-generating article comprising: a first element comprising an aerosol- generating substrate; and a tubular element according to any of EX1 to EX8 upstream or downstream of the first element.

[0264] EX10. The aerosol-generating article according to EX9, wherein the tubular element is adjacent to the first element.

[0265] EX11. The aerosol-generating article according to EX10, wherein the first end wall of the tubular element is adjacent to the tubular element.

[0266] EX12. The aerosol-generating article according to EX11, wherein the first end wall of the tubular element is in contact with the aerosol-generating substrate.

[0267] EX13. The aerosol-generating article according to any of EX9 to EX12, wherein the aerosol- generating substrate is an aerosol-generating substrate rod, and wherein the first element further comprises a susceptor element arranged within the aerosol-generating substrate rod.

[0268] EX14. The aerosol-generating article according to EX13, wherein the susceptor element is an elongate susceptor arranged longitudinally within the aerosol-generating substrate.

[0269] EX15. The aerosol-generating article according to any of EX9 to EX14, wherein the tubular element is a first tubular element and is located downstream of the aerosol-forming substrate, wherein the first end wall of the first tubular element is adjacent to a downstream end of the aerosol- generating substrate.

[0270] EX16. The aerosol-generating article according to EX15, wherein the ventilation zone is located in a downstream section of the first tubular element.

[0271] EX17. An aerosol-generating article according to EX15 or EX16, further comprising a second tubular element comprising: a tubular body defining a cavity extending from a first end of the tubular body to a second end of the tubular body; and a folded end portion forming a first end wall at the first end of the tubular body, the first end wall delimiting an opening for airflow between the cavity of the second tubular element and the exterior, wherein the second tubular element is positioned upstream of the aerosol-generating substrate, wherein the first end wall of the second tubular element is adjacent to the upstream end of the aerosol-generating substrate.

[0272] EX18. An aerosol-generating article according to EX17, wherein the second tubular element further comprises a folded end portion forming a second end wall at the second end of the tubular body, the second end wall delimiting an opening for airflow between the cavity of the second tubular element and the exterior.

[0273] EX19. An aerosol-generating article according to EX18, wherein the opening delimited by the second end wall of the second tubular element is smaller than the opening delimited by the first end wall of the second tubular element.

[0274] EX20. An aerosol-generating article according to any of EX17 to EX19, wherein the second tubular element is the most upstream component of the aerosol-generating article.

[0275] EX21. An aerosol-generating article according to any of EX15 to EX20, further comprising a ventilation zone at a location along the first tubular element.

[0276] EX22. An aerosol-generating article according to any of EX15 to EX22, further comprising a mouthpiece element positioned downstream of the first tubular element.

[0277] EX23. An aerosol-generating article according to EX22, wherein the mouthpiece element comprises a segment of filter material.

[0278] EX24. An aerosol-generating article according to any of EX1 to EX23, wherein the cavity in the tubular body is a hollow cavity.

[0279] It will be appreciated that features described in relation to one example or embodiment can also be applicable to other examples and embodiments. For example, it will be appreciated that features described hitherto in relation to one or more of the devices, the use of the devices, and the components of the devices configured to perform particular functions for carrying out the method of operating the device are equally disclosed as a method of operating the device. For example, the disclosure of a crimping device configured to crimp a band of material is equally a disclosure of the method steps of crimping a band of material with a crimping device. BRIEF DESCRIPTION OF DRAWINGS

[0280] The application will now be further described, by way of example only, with reference to the accompanying drawings in which:

[0281] Figure 1 a schematic side view cross-section of an aerosol-generating article according to a first embodiment of the application is shown;

[0282] Figure 2 a schematic side view cross-section of an aerosol-generating article according to a second embodiment of the application is shown;

[0283] Figure 2 a schematic side view cross-section of an aerosol-generating article according to a third embodiment of the application is shown;

[0284] Figure 4 a perspective view of a tubular element of an aerosol-generating article of the first embodiment of the application is shown; and

[0285] Figures 5A-5D a schematic side view cross-section of a tubular element of an aerosol-generating article depicting Figure 1 a formation stage of the aerosol-generating article is shown;

[0286] Figure 6 a schematic side view cross-section of an aerosol-generating article according to a fourth embodiment of the application is shown;

[0287] Figure 7 a schematic side view cross-section of an aerosol-generating article according to a fifth embodiment of the application is shown;

[0288] Figure 8 a schematic side view cross-section of an aerosol-generating article according to a sixth embodiment of the application is shown;

[0289] Figure 9 a schematic side view cross-section of an aerosol-generating article not according to an embodiment of the application is shown;

[0290] Figure 10A and 10B a gas flow field depicting a comparison of an aerosol-generating article according to an embodiment of the application with an aerosol-generating article not according to the application is shown; and

[0291] Figure 11A and 11B a gas flow field depicting a comparison of an aerosol-generating article according to an embodiment of the application with an aerosol-generating article not according to the application is shown. DETAILED DESCRIPTION

[0292] Figure 1An aerosol-generating article 1 according to a first embodiment of the application is shown. The aerosol-generating article 1 comprises a first element 11 having an aerosol- generating substrate 12 and a downstream section 14 at a location downstream of the first element 11. Further, the aerosol-generating article 1 comprises an upstream section 16 at a location upstream of the first element 11. Thus, the aerosol-generating article 1 extends from an upstream or distal end 18 to a downstream or mouth end 20.

[0293] The aerosol-generating article has an overall length of about 45 millimetres.

[0294] The downstream section 14 comprises a tubular element 100 located immediately downstream of the first element 11, which tubular element 100 is longitudinally aligned with the first element 11. In Figure 1 embodiments, the upstream end of the tubular element 100 abuts the downstream end of the first element 11 and, in particular, the downstream end of the aerosol-generating substrate 12.

[0295] Further, the downstream section 14 comprises a mouthpiece element 42 at a location downstream of the tubular element 100. In more detail, the mouthpiece element 42 is positioned immediately downstream of the tubular element 100. As Figure 1 shown, the upstream end of the mouthpiece element 42 adjoins the downstream end 40 of the tubular element 100.

[0296] The mouthpiece element 42 is provided in the form of a cylindrical filter segment of low density cellulose acetate. The mouthpiece element 42 has a length of about 12 millimetres and an outer diameter of about 7.25 millimetres. The RTD of the mouthpiece element 42 is about 12 millimetres H20.

[0297] The aerosol-generating article 1 comprises a ventilation zone 60 provided at a location along the tubular element 100. In more detail, the ventilation zone is provided at about 4 millimetres from the downstream end of the tubular element 100. The ventilation level of the aerosol-generating article 10 is about 40%.

[0298] The first element 11 is in the form of a rod comprising an aerosol-generating substrate 12 of one of the above-mentioned types. The aerosol-generating substrate 12 can substantially define the structure and dimensions of the rod 11. The rod 11 can further comprise a wrapper (not shown) surrounding the aerosol-generating substrate 12. The rod 11 comprising the aerosol-generating substrate has an outer diameter of about 7.25 millimetres and a length of about 12 millimetres.

[0299] The first element 11 further comprises an elongate susceptor element 44 within the aerosol-generating substrate 12. In more detail, the susceptor element 44 is arranged substantially longitudinally within the aerosol-generating substrate 12 so as to be generally parallel to the longitudinal direction of the rod 11. As Figure 1 shown in the drawing, the susceptor element 44 is positioned in a radially central position within the rod and effectively extends along the longitudinal axis of the rod 11.

[0300] The susceptor element 44 extends from the upstream end to the downstream end of the aerosol- generating substrate 12. Indeed, the susceptor element 44 has substantially the same length as the first element 11 comprising the aerosol-generating substrate 12.

[0301] In Figure 1 embodiments, the susceptor element 44 is provided in the form of a strip and has a length of about 12 millimetres, a thickness of about 60 micrometres and a width of about 4 millimetres.

[0302] The upstream section 16 comprises an upstream element 46 located immediately upstream of the first element 11, the upstream element 46 being longitudinally aligned with the first element 11. In Figure 1 embodiments, the downstream end of the upstream element 46 abuts the upstream end of the first element 11 and, in particular, the upstream end of the aerosol-generating substrate 12. This advantageously prevents the susceptor element 44 from being removed. Furthermore, this ensures that the consumer does not accidentally touch the heated susceptor element 44 after use.

[0303] The upstream element 46 is provided in the form of a cylindrical cellulose acetate filter segment defined by a rigid wrapper. The upstream element 46 has a length of about 5 millimetres. The RTD of the upstream element 46 is about 30 millimetres H20.

[0304] The aerosol-generating article 1 further comprises an outer wrapper 109 which at least surrounds the tubular element. As Figure 1 shown in the drawings, the outer wrapper also surrounds the first element 11, the mouthpiece element 42 and the upstream element 46. The outer wrapper 109 extends from the upstream or distal end 18 to the downstream or mouth end 20.

[0305] The tubular element 100 comprises a tubular body 103 defining a lumen 106 extending from a first end 101 of the tubular body 103 to a second end 102 of the tubular body 103. The tubular element 100 further comprises a folded end portion forming a first end wall 104 at the first end 101 of the tubular body 103. The first end wall 104 delimits an opening 105 allowing airflow between the lumen 106 of the tubular element 100 and the outside. In particular, Figure 1 embodiments are configured such that aerosol can flow from the first element 11 through the opening 105 into the lumen 106.

[0306] The lumen 106 of the tubular body 103 is substantially empty and thus a substantially non-restrictive airflow is achieved along the lumen 106. Thus, the RTD of the tubular element 100 can be located at a specific longitudinal position of the tubular element 100, i.e. at the first end wall 104, and can be controlled by the selected configuration of the first end wall 104 and its corresponding opening 105. In Figure 1In embodiments of the tubular element 100, the RTD of the tubular element 100 (which is essentially the RTD of the first end wall 104) is substantially 10 millimetres H20. In Figure 1 In embodiments of the tubular element 100, the tubular element 100 has a length of about 16 millimetres, an outer diameter of about 7.25 millimetres and an inner diameter (D FTS ) of about 6.5 millimetres. Thus, the thickness of the peripheral wall of the tubular body 103 is about 0.75 millimetres.

[0307] As shown in Figure 1 and in more detail in the perspective view of Figure 4 , the first end wall 104 extends substantially transverse to the longitudinal direction of the aerosol-generating article 1 and the longitudinal direction of the tubular element 100. The opening 105 is the only opening in the first end wall 104 and the opening 105 is positioned in a generally radially central position of the tubular element 100. Thus, the first end wall 104 is generally annular.

[0308] The combination of the first end wall 104 and its corresponding opening 105 provides an effective barrier arrangement which can restrict movement of the aerosol-generating substrate while also enabling one or both of air and aerosol to flow from the first element 11 and through the opening 105 into the cavity 106. The opening 105 is generally aligned with the radially central position of the susceptor element 44 of the first element 11. This can be advantageous because it helps to maintain a distance between the first end wall 105 and the susceptor and thus reduces undesirable heating of the first end wall 105. This can also be advantageous because it can provide a direct unobstructed downstream flow of aerosol generated by the portion of the aerosol-generating substrate in close proximity to the susceptor element 44.

[0309] As will be described in more detail below with respect to Figures 5A-5D , the first end wall 104 is formed by folding an end portion of the tubular element 100 about a fold point. The fold point generally corresponds to the first end of the tubular body 103 of the tubular element 100.

[0310] Figure 2 An aerosol-generating article 2 according to a second embodiment of the application is shown. The aerosol-generating article 2 of the second embodiment is generally the same as the aerosol-generating article 1 of the first embodiment, except that the aerosol-generating article 2 of the second embodiment does not comprise an upstream element 46 provided in the form of a cylindrical cellulose acetate filter segment defined by a rigid wrapper. Instead, the aerosol-generating article 2 of the second embodiment comprises a second tubular element 200 located immediately upstream of the first element 11. Thus, in this second embodiment, the tubular element 100 located immediately downstream of the first element 11 is referred to as the first tubular element 100.

[0311] The second tubular element 200 comprises a tubular body 203 defining a cavity 206 extending from a first end of the tubular body 203 to a second end of the tubular body 203. The tubular element 200 further comprises a folded end portion forming a first end wall 204a at the first end of the tubular body 103. The first end wall 204a delimits an opening 205a allowing airflow between the cavity 206 of the second tubular element 200 and the outside. In particular, Figure 2 Embodiments of the second tubular element 200 are configured such that air can flow from the cavity 206 through the opening 205a and into the first element 11.

[0312] The second tubular element 200 is thus similar to the first tubular element 100 in that an end portion of the tubular element 200 is folded to form an end wall 205a which extends substantially transversely to the longitudinal direction of the aerosol-generating article and is disposed adjacent to an end of the aerosol-generating substrate 12. In this case, the second tubular element 200 is disposed upstream of the first element 11 containing the aerosol-generating substrate 12 rather than downstream, which means that the end wall 204a is disposed adjacent to the upstream end of the aerosol-generating substrate 12.

[0313] However, unlike the first tubular element, the second tubular element 200 further comprises a second end wall 204b at the second end of its tubular body 203. This second end wall 204b is formed by folding an end portion of the second tubular element 200 at the second end of the tubular body of the second tubular element 200. The second end wall 204b delimits an opening 205b allowing airflow between the cavity 206 of the second tubular element 200 and the outside. In the case of the second end wall 204b, the opening 205b is configured such that air can flow from the outside of the aerosol-generating article 2 through the opening 205b and into the cavity 206. Thus, the opening 205b provides a conduit through which air can be drawn into the aerosol-generating article 2 and through the aerosol-generating substrate 12. In Figure 2 In embodiments of the second tubular element 200, the first end wall 204a of the second tubular element 200 can be referred to as a downstream end wall of the second tubular element 200. Similarly, the second end wall 204b of the second tubular element 200 can be referred to as an upstream end wall of the second tubular element 200.

[0314] Figure 3An aerosol-generating article 3 according to a third embodiment of the application is shown. The aerosol-generating article 3 of the third embodiment is substantially the same as the aerosol-generating article 1 of the first embodiment, except that the aerosol-generating article 3 of the third embodiment does not comprise any form of upstream element 46 upstream of the first element 11. Thus, the upstream or distal end 18 of the aerosol-generating article 3 is defined by the first element 11. Furthermore, in the third embodiment of the application, the first element 11 does not comprise a susceptor element 44 located within the aerosol-generating substrate 12. Thus, such an aerosol-generating article 3 can be an aerosol-generating article configured to receive a heater blade of an aerosol-generating device. The heater blade can be inserted into the aerosol-generating substrate 12 through the upstream end 18 of the aerosol-generating article 3.

[0315] The tubular element 300 of the aerosol-generating article 3 of the third embodiment is substantially the same as the tubular element 100 of the aerosol-generating article 1 of the first embodiment, except that the tubular element 300 is longer than the tubular element 100.

[0316] Figures 5A-5D A tubular element for an aerosol-generating article according to the application is shown through different stages of its formation. Thus, these figures show a method of forming a tubular element, for example Figure 1 the tubular element 100.

[0317] As shown in Figure 5A , the method starts with providing a tubular element 500 comprising a first end portion 504 and a tubular body 103 adjacent and integral with the first end portion 504. To form the first end wall 104, a folding force is applied to the tubular element 500 to bend the first end portion 504 about a folding point 501 corresponding to a first end of the tubular body 103.

[0318] The folding force deflects the first end portion 504 inwardly (as indicated by the dashed curved arrow in Figure 5A , 5B and 5C) relative to the tubular body 103 and towards the cavity 106 of the tubular body 103. The folding force continues to be applied until the first end portion 504 has been folded through an angle of more than 90 degrees, as measured relative to the wall of the tubular body 103. Such a position is depicted in Figure 5C . As can be seen from Figure 5C , in this position at least a portion of the first end portion 504 of the tubular element 500 extends into the cavity 106 of the tubular body 103. In other words, at least a portion of the first end portion 504 of the tubular element 500 has a longitudinal position between the position of the first end of the tubular body 103 and the position of the second end of the tubular body 103.

[0319] Once the first end portion 504 has reached Figure 5Cthe position of the first end portion 504, the application of the folding force is stopped. At this point, the inherent elastic properties of the paper material (e.g. paper, paperboard or cardboard) of the tubular element 500 will cause the first end portion 504 to partially recover along its folding path, so that the first end portion 504 reaches a position where it extends substantially transversely to the longitudinal direction of the tubular body 103. This position is indicated by the dashed line in Figure 2. Figure 5D is shown, the figure depicts the fully formed tubular element 100. In particular, the folded first end portion 504 forms a first end wall 104 at the first end of the tubular body 103, the first end wall 104 delimiting an opening 105 for air flow between the cavity 106 of the tubular element 100 and the outside.

[0320] In the arrangement of Figure 3, the second end of the tubular element 500 is not folded; however, it will be appreciated that similar method steps can be applied to this second end of the tubular element 500 in order to obtain a tubular element having two folded end portions, each forming a respective first end wall and second end wall of the tubular element. Figures 5A-5D

[0321] Figure 6 An aerosol-generating article 6 according to a fourth embodiment of the application is shown. The aerosol-generating article 6 of the fourth embodiment is substantially identical to the aerosol-generating article 3 of the third embodiment, and similar reference numerals are used where appropriate. However, the aerosol-generating article 6 of the fourth embodiment does not comprise a mouthpiece element 42 at a position downstream of the tubular element 600. Instead, Figure 6 The tubular element 600 extends from the downstream end of the aerosol-forming substrate 12 all the way to the mouth end 20 of the aerosol-generating article 6. Thus, Figure 6 The downstream section 14 of the aerosol-generating article 6 in Figure 3 is formed entirely by the tubular element 600.

[0322] Furthermore, in the embodiment of Figure 3, the first end wall 604 of the tubular element 600 is not provided adjacent to the downstream end of the aerosol-forming substrate 12. Instead, the first end wall 604 of the tubular element 600 is provided at the mouth end 20 of the aerosol-generating article 6. The first end wall 604 delimits an opening 605 which allows air flow between the cavity 606 of the tubular element 600 and the outside. The opening 605 is configured such that one or both of air and aerosol can flow from the cavity 606 through the opening 605b to the outside of the aerosol-generating article 6. Figure 6

[0323] Figure 7 ​​An aerosol-generating article 7 according to a fifth embodiment of the application is shown. The aerosol-generating article 7 of the fifth embodiment is generally the same as the aerosol-generating article 6 of the fourth embodiment, and similar reference numerals are used where appropriate. However, the aerosol-generating article 7 of the fifth embodiment now comprises a mouthpiece element in the form of a hollow tube 742 at a location downstream of the tubular element 700. Thus, Figure 7 The tubular element 700 extends all the way to the upstream end of this hollow tube 742. Thus, Figure 6 The downstream section 14 of the aerosol-generating article 6 in

[0324] Figure 8 An aerosol-generating article 8 according to a sixth embodiment of the application is shown. The aerosol-generating article 8 of the sixth embodiment is generally the same as the aerosol-generating article 1 of the first embodiment, and similar reference numerals are used where appropriate.

[0325] However, in the embodiment of Figure 8 The tubular element 800 does not contact the first element 11 comprising the aerosol-generating substrate 12. Instead, there is a blank space 850 between the downstream end of the first element 11 and the first end wall 804 at the upstream end 801 of the tubular element 800. Thus, in the embodiment of Figure 8 The first end wall 804 of the tubular element 800 does not provide a barrier in contact with the aerosol-generating substrate 12 for limiting movement of the aerosol-generating substrate 12 in the embodiment of

[0326] Figure 9 An aerosol-generating article 9 not according to the application is shown. The aerosol-generating article 9 has similarities to the aerosol-generating article 1 of the first embodiment of the application in Figure 1 and similar reference numerals are used where appropriate. However, Figure 9 The aerosol-generating article 9 of does not comprise a tubular element according to the application. In particular, in contrast to Figure 1 the aerosol-generating article 1, Figure 9 The aerosol-generating article 9 of does not comprise a tubular element 100 between the first element 100 and the mouthpiece element 42. Instead, Figure 9 The aerosol-generating article 9 of comprises two hollow acetate tubes between the first element 100 and the mouthpiece element 42. These are a first hollow acetate tube 980 located immediately downstream of the first element 11 and a second hollow acetate tube 990 located immediately downstream of the first hollow acetate tube 980.

[0327] Figure 10A and Figure 10B The airflow field generated in the computational fluid dynamics (CFD) simulation is depicted, which will be based on Figure 1 Aerosol-generating articles including tubular elements (hereinafter referred to as Example A) and according to Figure 9 The aerosol-generating articles comprising two known hollow acetic acid tubes (hereinafter referred to as Comparative Example A) are compared. Figure 10A The airflow field during a simulated 0.25-second suction is shown. Figure 10B The airflow field is shown when the simulated suction lasts for 1 second.

[0328] Example A's aerosol-generating article comprises the following elements placed adjacent to each other, starting from the upstream end of the aerosol-generating article: a cylindrical cellulose acetate filter tip segment (length: 5 mm); an aerosol-forming matrix formed of coiled tobacco sheets gathered around a receptor (length: 12 mm); a tubular element having a folded end portion forming a first end wall adjacent to the aerosol-forming matrix (length: 16 mm); and a cellulose acetate mouth-end filter tip segment (length: 12 mm).

[0329] The aerosol-generating article of Comparative Example A consists of elements similar to those of the article of Example A, except that the tubular elements have been replaced by two hollow acetate tubes of equal length. Therefore, the aerosol-generating article of Comparative Example A consists of the following elements placed adjacent to each other, starting from the upstream end of the aerosol-generating article: a cylindrical cellulose acetate filter tip section (length: 5 mm); an aerosol-forming matrix formed of coiled tobacco sheets clustered around the receptors (length: 12 mm); a first hollow acetate tube (length: 8 mm); a second hollow acetate tube (length: 8 mm); and a cellulose acetate end filter tip section (length: 12 mm).

[0330] A single-line ventilation providing a 40% ventilation level is provided around the tubular element of Example A, and this single-line ventilation is positioned 5 mm downstream of the tubular element. A second hollow acetic acid tube of Comparative Example A is also provided with a single-line ventilation providing a 40% ventilation level, and this single-line ventilation is positioned 5 mm downstream of the second hollow acetic acid tube.

[0331] As from Figure 10A As can be seen, after 0.25 seconds of suction, the mixing of air drawn in through the aerosol-forming matrix with fresh air drawn in through the ventilation holes was significantly more pronounced in Example A than in Comparative Example A. The higher velocity values ​​were also more significant in Example A compared to Comparative Example A.

[0332] like Figure 10B As shown, this phenomenon further develops as suction progresses over time. Specifically, in Figure 10BIn the middle, after 1 second of puffing, jet instability and additional velocity increase can be seen for Example A, which is not present for Comparative Example A. Such jet instability can improve the mixing of hot air drawn through the aerosol-forming substrate with fresh air drawn through the ventilation hole. This can lead to more favorable conditions for nucleation and growth of aerosol particles within the tubular element when compared to the hollow acetate tube of Comparative Example A. Without wishing to be bound by theory, it is believed that this favorable condition is particularly promoted in Example A by the combined use of the first end wall of the tubular element and the ventilation line provided around the tubular element. In particular, the first end wall of the tubular element can provide a partial restriction where air can flow into and out of the tubular element. This partial restriction appears to particularly effectively promote the mixing of hot air drawn through the aerosol-forming substrate with fresh air drawn through the ventilation hole when this partial restriction is combined with the ventilation downstream of the restriction.

[0333] Figure 11A and 11B depicts the air temperature field generated in a computational fluid dynamics (CFD) simulation and provides a comparison of these for the aerosol-generating article of Example A and the aerosol-generating article of Comparative Example A. Figure 11A shows the air temperature field into a simulated puff of 0.25 seconds, Figure 10B shows the air temperature field into a simulated puff of 1 second. As Figure 11A and 11B It is clear from the middle that a more uniform distribution and higher temperatures are achieved within the tubular element of Example A when compared to the hollow acetate tube of Comparative Example A. This is evident after 0.25 seconds of puffing and also after 1 second of puffing.

Claims

1. A tubular element for an aerosol-generating article, the tubular element comprising: a tubular body defining a cavity extending from a first end of the tubular body to a second end of the tubular body; a folded end portion forming a first end wall at the first end of the tubular body, the first end wall delimiting an opening for airflow between the cavity of the tubular element and the exterior; and a ventilation zone at a location along the tubular body of the tubular element; wherein the ventilation zone is located between 5 millimetres and 15 millimetres from the folded end portion of the tubular element.

2. The tubular element according to claim 1, wherein the ventilation zone comprises a plurality of perforations through the tubular body.

3. The tubular element according to claim 1 or 2, wherein the ventilation zone comprises at least one circumferential row of perforations extending around the tubular body.

4. The tubular element according to claim 1 or 2, wherein the tubular element has a ventilation level of 20% to 70%.

5. The tubular element according to claim 1 or 2, wherein the tubular element is formed of a paper material.

6. The tubular element according to claim 1 or 2, wherein at least a first portion of the tubular element forming the first end wall is air impermeable.

7. The tubular element according to claim 1 or 2, wherein the first end wall extends partially into the cavity of the tubular body and forms an angle of less than 90 degrees with an inner surface of the tubular body.

8. An aerosol-generating article comprising: a first element comprising an aerosol-generating substrate; and a tubular element according to any one of claims 1 to 7, the tubular element being upstream or downstream of the first element.

9. The aerosol-generating article according to claim 8, wherein the tubular element is adjacent to the first element.

10. The aerosol-generating article according to claim 9, wherein the first end wall of the tubular element is adjacent to the aerosol-generating substrate.

11. The aerosol-generating article according to claim 10, wherein the first end wall of the tubular element is in contact with the aerosol-generating substrate.

12. The aerosol-generating article according to any one of claims 8 to 11, wherein the aerosol-generating substrate is a rod of aerosol-generating substrate, and wherein the first element further comprises a susceptor element arranged within the rod of aerosol-generating substrate.

13. The aerosol-generating article according to any one of claims 8 to 11, wherein the tubular element is a first tubular element and is downstream of the aerosol-generating substrate, wherein the first end wall of the first tubular element is adjacent to a downstream end of the aerosol-generating substrate.

14. The aerosol-generating article according to claim 13, wherein the ventilation zone is located in a downstream section of the first tubular element.

15. A tubular element for an aerosol-generating article, the tubular element comprising: ​ ​ a tubular body defining a cavity extending from a first end of the tubular body to a second end of the tubular body; a folded end portion forming a first end wall at the first end of the tubular body, the first end wall delimiting an opening for airflow between the cavity of the tubular element and the exterior; and a ventilation zone at a location along the tubular body of the tubular element; and wherein the tubular element has a ventilation level of 20% to 70%.

16. The tubular element according to claim 15, wherein the ventilation zone comprises a plurality of perforations through the tubular body.

17. The tubular element according to claim 15 or claim 16, wherein the ventilation zone is located between 5 millimetres and 15 millimetres from the folded end portion of the tubular element.

18. The tubular element according to claim 15 or claim 16, wherein the ventilation zone comprises at least one circumferential row of perforations extending around the tubular body.

19. The tubular element according to claim 15 or claim 16, wherein the tubular element is formed from a paper material.

20. The tubular element according to claim 15 or claim 16, wherein at least a first portion of the tubular element forming the first end wall is air impermeable.

21. The tubular element according to claim 15 or claim 16, wherein the first end wall extends partially into the cavity of the tubular body and forms an angle of less than 90 degrees with an inner surface of the tubular body.

22. An aerosol-generating article comprising: a first element comprising aerosol-generating substrate; and a tubular element according to any one of claims 15 to 21, the tubular element being upstream or downstream of the first element.

23. The aerosol-generating article according to claim 22, wherein the tubular element is adjacent to the first element.

24. The aerosol-generating article according to claim 23, wherein the first end wall of the tubular element is adjacent to the aerosol-generating substrate.

25. The aerosol-generating article according to claim 24, wherein the first end wall of the tubular element is in contact with the aerosol-generating substrate.

26. The aerosol-generating article according to any one of claims 22 to 25, wherein the aerosol-generating substrate is a rod of aerosol-generating substrate, and wherein the first element further comprises a susceptor element arranged within the rod of aerosol-generating substrate.

27. The aerosol-generating article according to any one of claims 22 to 25, wherein the tubular element is a first tubular element and is downstream of the aerosol-generating substrate, wherein the first end wall of the first tubular element is adjacent to a downstream end of the aerosol-generating substrate.

28. The aerosol-generating article according to claim 27, wherein the ventilation zone is located in a downstream section of the first tubular element.

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