Aerosol-generating article comprising tubular element having opening

Abstract

An aerosol-generating article (1) is provided. The aerosol-generating article (1) comprises a first element (11) comprising an aerosol-forming substrate (12). The aerosol-generating article further comprises a tubular element (100) positioned downstream of the first element (11). The tubular element (100) has a radial central axis and includes an end wall (104) formed by a folded end portion of the tubular element. The end wall (104) defines an opening (110) having a perimeter. An opening (110) is used to fluidly connect an interior of the tubular element and an exterior of the tubular element. The radial central axis of the tubular element is positioned outside the periphery of the opening. A method of forming a tubular element for an aerosol-generating article is also provided.

Description

Technical Field

[0001] The present invention relates to an aerosol-generating article comprising an aerosol-forming substrate, wherein the aerosol-generating article is adapted to generate an inhalable aerosol upon heating the aerosol-forming substrate. Background Art

[0002] Aerosol-forming articles in which an aerosol-forming substrate, such as a tobacco-containing substrate, is heated rather than burned are known in the art. Typically, in such heated aerosol-forming articles, an aerosol is generated by transferring heat from a heat source to a physically separate aerosol-forming substrate or material, which may be positioned in contact with, within, around, or downstream of the heat source. During use of the aerosol-forming article, volatile compounds are released from the aerosol-forming substrate by heat transfer from the heat source. The volatile compounds are then entrained in the air drawn through the aerosol-generating article. As the volatile compounds cool, they condense and form an aerosol.

[0003] It is known to provide aerosol-generating articles with one or more elements downstream of an aerosol-forming substrate, the one or more elements being configured to perform certain functions. For example, WO 2013 / 120565 A2 discloses an aerosol-generating article comprising an aerosol-cooling element for cooling an aerosol formed from the substrate. In one embodiment disclosed in WO 2013 / 120565 A2, a hollow cellulose acetate tube is positioned immediately downstream of the aerosol-forming substrate, and an aerosol-cooling element made of a polylactic acid sheet is positioned downstream of the hollow cellulose acetate tube. The function of the hollow cellulose acetate tube is described as preventing the aerosol-forming substrate from being pushed downstream when a heating element is inserted into the aerosol-forming substrate.

[0004] Providing an aerosol-generating article with such elements downstream of the aerosol-forming substrate can increase the cost and complexity of manufacturing the aerosol-generating article. Furthermore, such elements downstream of the aerosol-forming substrate can have an undesirable effect on the resistance to draw (RTD) of the aerosol-generating article. For example, an aerosol-generating article with an RTD that is too low or too high can result in an unsatisfactory user experience. Summary of the Invention

[0005] It would be desirable to provide an aerosol-generating article having an element downstream of an aerosol-forming substrate that can perform one or more of the functions described above while being relatively simple and inexpensive to manufacture. It would also be desirable that such an element could provide improved functionality over known prior art downstream elements. It would further be desirable that the RTD of the element could be controlled to provide a satisfactory RTD.

[0006] The present disclosure relates to an aerosol-generating article. The aerosol-generating article may include a first element. The first element may include an aerosol-forming substrate. The aerosol-generating article may also include a tubular element positioned downstream of the first element. The tubular element may have a radial central axis and may include an end wall formed by a folded end portion of the tubular element. The end wall may define an opening. The opening may have a perimeter. The opening may have a geometric center. The opening may be configured to fluidly connect an interior of the tubular element to an exterior of the tubular element.

[0007] The radial center axis of the tubular element may be positioned outside the periphery of the opening. The periphery of the opening may not define the radial center axis of the tubular element. The radial center axis may not extend through the opening. Additionally or alternatively, the geometric center of the opening may be radially spaced from the radial center axis of the tubular element. For example, the geometric center of the opening may be radially spaced from the radial center axis of the tubular element by at least 10% of the diameter of the end wall.

[0008] According to a first aspect of the present invention, an aerosol-generating article is provided. The aerosol-generating article comprises a first element comprising an aerosol-forming substrate. The aerosol-generating article further comprises a tubular element positioned downstream of the first element. The tubular element has a radial central axis and includes an end wall formed by a folded end portion of the tubular element. The end wall defines an opening having a periphery. The opening is for fluidly connecting an interior of the tubular element with an exterior of the tubular element. The radial central axis of the tubular element is positioned outside the periphery of the opening.

[0009] The tubular element of the present invention is particularly suitable for acting as an aerosol-cooling element. When the aerosol-forming substrate is heated, volatile compounds are released, and when a user draws on the mouth end of the aerosol-generating article, the volatile compounds are entrained in the air drawn through the aerosol-generating article. The tubular element is positioned downstream of the aerosol-forming substrate. Therefore, when air and volatile compounds are drawn toward the mouth end of the aerosol-generating article, they can pass through the interior of the tubular element. This can allow heat to be transferred from the air and volatile compounds to the relatively cool structure of the tubular element and subsequently dissipated into the environment.

[0010] By providing an opening in the end wall such that the radial center axis of the tubular element is positioned outside the periphery of the opening, such an opening can be radially spaced from or offset relative to the radial center axis of the tubular element and positioned toward the outer periphery of the end wall. Consequently, air and volatile compounds flowing through the opening can be closer to the tubular wall of the tubular element than with a centrally positioned opening. Advantageously, this can increase the amount of heat transferred from the air and volatile compounds to the tubular wall of the tubular element.

[0011] By providing an end wall formed by a folded end portion of the tubular element, the tubular element can be configured to have a desired RTD by configuring the size and shape of the end wall and the opening. In particular, the tubular element and its end wall can be manufactured efficiently and at high speeds with a satisfactory RTD and low RTD variability from one article to another. Furthermore, the configuration of the tubular element and its end wall means that the RTD can be localized at a specific longitudinal position of the tubular element, rather than being continuously distributed along the length of the tubular element.

[0012] According to a second aspect of the present invention, an aerosol-generating article is provided. The aerosol-generating article comprises a first element comprising an aerosol-forming substrate. The aerosol-generating article further comprises a tubular element positioned downstream of the first element. The tubular element has a radial central axis and comprises an end wall formed by a folded end portion of the tubular element. The end wall defines an opening having a geometric center. The opening is for fluidly connecting an interior of the tubular element and an exterior of the tubular element. The geometric center of the opening is radially spaced from the radial central axis of the tubular element by at least 10% of a diameter of the end wall.

[0013] As used herein, the term "end wall" refers to the wall at the most upstream end or the most downstream end of a tubular element.

[0014] As used herein, the term "aerosol-generating article" refers to an article in which an aerosol-forming substrate is heated to generate and deliver an inhalable aerosol to a consumer.

[0015] As used herein, the term "aerosol-forming substrate" refers to a substrate that is capable of releasing volatile compounds upon heating to generate an aerosol.

[0016] As used herein, the term "rod" refers to a generally cylindrical element having a substantially polygonal cross-sectional area and preferably having a circular, oval or elliptical cross-section.

[0017] As used herein, the term "longitudinal" refers to a direction corresponding to the principal longitudinal axis of the aerosol-generating article, which extends between the upstream and downstream ends of the aerosol-generating article. During use, air is drawn through the aerosol-generating article in the longitudinal direction. The radial central axis extends in the longitudinal direction.

[0018] As used herein, the terms "upstream" and "downstream" describe the relative position of an element or part of an element of an aerosol-generating article with respect to the direction in which aerosol is transported through the aerosol-generating article during use.

[0019] The term "transverse" refers to a direction perpendicular to the longitudinal direction. Unless otherwise stated, any reference to a "cross-section" of an aerosol-generating article or component of an aerosol-generating article refers to the cross-sectional area.

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

[0021] As used herein, the term "tubular element" is used to refer to a generally elongated element that defines an interior cavity or airflow passageway along its longitudinal axis. In particular, the term "tubular" will hereinafter be used to refer to a tubular element having a substantially cylindrical cross-sectional area and defining at least one airflow conduit that establishes uninterrupted fluid communication between an upstream end of the tubular element and a downstream end of the tubular element. However, it should be understood that alternative geometries (e.g., alternative cross-sectional shapes) of the tubular element may 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, such as twice or more its width dimension or its diameter dimension.

[0023] A conventional cigarette is lit when a user applies a flame to one end of the cigarette and draws air through the other end. Localized heat provided by the flame and the oxygen in the air drawn through the cigarette causes the end of the cigarette to ignite, and the resulting combustion generates inhalable smoke. In contrast, in heated aerosol-generating articles, aerosol is generated by heating an aerosol-forming substrate, such as tobacco. Known heated aerosol-generating articles include, for example, electrically heated aerosol-generating articles and aerosol-generating articles in which aerosol is generated by heat transfer from a combustible fuel element or heat source to a physically separate aerosol-forming material.

[0024] The aerosol-generating article according to the present invention may be a heated aerosol-generating article. The aerosol-generating article according to the present invention may be an electrically heated aerosol-generating article. For example, the aerosol-generating article according to the present invention finds particular application in aerosol-generating systems comprising an electrically heated aerosol-generating device having an internal heater blade adapted to be inserted into an aerosol-forming substrate.

[0025] As used herein, the term "aerosol-generating device" refers to a device comprising a heater element that interacts with an aerosol-forming substrate of an aerosol-generating article to generate an aerosol.

[0026] The end wall may be positioned at the upstream end of the tubular element. In other words, the end wall may be an upstream end wall. In this configuration, air and volatile compounds pass through the opening before entering the interior of the tubular element. This can promote turbulent flow downstream of the opening and, therefore, within the interior of the tubular element. Advantageously, the turbulent flow can increase the rate of heat transfer from the air and volatile compounds to the tubular wall of the tubular element. Furthermore, the upstream end wall can prevent undesirable components, such as solid matrix particles, from entering the interior of the tubular element, which could adversely affect the cooling and nucleation efficiency of the tubular element.

[0027] The end wall may be positioned at the downstream end of the tubular element. In other words, the end wall may be a downstream end wall. In this configuration, the opening defined by the downstream end wall may be used to accelerate and thereby cool the aerosol as it leaves the tubular element.

[0028] The first element and the tubular element may be adjacent to each other. This can limit the extent to which undesirable components, such as tobacco particles, can pass downstream before being blocked by the end wall. This can also allow the tubular element to cool the aerosol before it interacts with any other elements downstream of the first element. Advantageously, this can reduce the need for downstream elements to be formed of heat-resistant materials.

[0029] The term "adjacent to" is used herein with respect to the tubular element and the first element to indicate that the tubular element is longitudinally positioned beside the first element. In particular, the term indicates that there are no other elements of the aerosol-generating article disposed between the first element and the tubular element in the longitudinal direction.

[0030] The first element and the tubular element may be adjacent to and in contact with each other. For example, the end wall of the tubular element may be adjacent to and in contact with the aerosol-forming substrate. When the first element and the tubular element are adjacent to and in contact with each other, the tubular element may restrict downstream movement of the aerosol-forming substrate. For example, in an embodiment with a downstream end wall, the tubular wall of the tubular element may contact the periphery of the first element or the aerosol-forming substrate and thereby restrict downstream movement. However, embodiments of the tubular element with an upstream end wall may be particularly effective in preventing the first element or the aerosol-forming substrate from moving downstream. In particular, such embodiments may be more effective than the end of a hollow cellulose acetate tube because the upstream end wall may be less resistant to deformation than the end of a hollow cellulose acetate tube. The construction of the tubular element may also be better suited to withstand the temperatures generated by the heating blades or the susceptor element.

[0031] The first element and the tubular element may be adjacent to each other and not in contact with each other. A small gap of empty space may separate the first element from the tubular element in the longitudinal direction of the aerosol-generating article. For example, an end wall of the tubular element may be adjacent to the aerosol-forming substrate but not in contact with the aerosol-forming substrate. The gap may be 2 mm or less. The gap may be 1 mm or less. Advantageously, such a gap may provide space for loose particles or clumps from the aerosol-forming substrate to accumulate during use of the aerosol-generating article.

[0032] The opening defined by the end wall can be the only opening in the end wall. In other words, the end wall can define a single opening, and the opening is a single opening. This can mean that the RTD of the tubular element is determined solely by the configuration (such as size and shape) of the single opening. Advantageously, this can make it easier to provide the tubular element with a desired RTD and reduce variability in RTD between different tubular elements.

[0033] The periphery of the opening may be radially spaced at least 0.5 mm from the radial center axis of the tubular element. The periphery of the opening may be radially spaced at least 0.8 mm from the radial center axis of the tubular element. The periphery of the opening may be radially spaced at least 1 mm from the radial center axis of the tubular element. The periphery of the opening may be radially spaced at least 1.2 mm from the radial center axis of the tubular element. The periphery of the opening may be radially spaced at least 1.5 mm from the radial center axis of the tubular element. The periphery of the opening may be radially spaced at least 1.8 mm from the radial center axis of the tubular element. The periphery of the opening may be radially spaced at least 2 mm from the radial center axis of the tubular element. The periphery of the opening may be radially spaced at least 2.5 mm from the radial center axis of the tubular element.

[0034] The perimeter of the opening may be radially spaced from the radial center axis of the tubular element by at least 1% of the diameter of the end wall. The perimeter of the opening may be radially spaced from the radial center axis of the tubular element by at least 3% of the diameter of the end wall. The perimeter of the opening may be radially spaced from the radial center axis of the tubular element by at least 5% of the diameter of the end wall. The perimeter of the opening may be radially spaced from the radial center axis of the tubular element by at least 7% of the diameter of the end wall. The perimeter of the opening may be radially spaced from the radial center axis of the tubular element by at least 10% of the diameter of the end wall. Preferably, the perimeter of the opening may be radially spaced from the radial center axis of the tubular element by at least 15% of the diameter of the end wall. More preferably, the perimeter of the opening may be radially spaced from the radial center axis of the tubular element by at least 20% of the diameter of the end wall. In some embodiments, the perimeter of the opening may be radially spaced from the radial center axis of the tubular element by at least 25% of the diameter of the end wall. In some other embodiments, the perimeter of the opening may be radially spaced from the radial center axis of the tubular element by at least 30% of the diameter of the end wall. The distance that the perimeter of the opening is radially spaced from the radial center axis is determined based on a minimum distance from the radial center axis of the tubular element to the perimeter of the opening.

[0035] The geometric center of the opening may be radially spaced at least 0.5 mm from the radial center axis of the tubular element. The geometric structure of the opening may be radially spaced at least 0.8 mm from the radial center axis of the tubular element. The geometric center of the opening may be radially spaced at least 1 mm from the radial center axis of the tubular element. The geometric center of the opening may be radially spaced at least 1.2 mm from the radial center axis of the tubular element. The geometric center of the opening may be radially spaced at least 1.5 mm from the radial center axis of the tubular element. The geometric center of the opening may be radially spaced at least 1.8 mm from the radial center axis of the tubular element. The geometric center of the opening may be radially spaced at least 2 mm from the radial center axis of the tubular element. The geometric center of the opening may be radially spaced at least 2.5 mm from the radial center axis of the tubular element.

[0036] The geometric center of the opening may be radially spaced from the radial center axis of the tubular element by at least 1% of the diameter of the end wall. The geometric center of the opening may be radially spaced from the radial center axis of the tubular element by at least 5% of the diameter of the end wall. The geometric center of the opening may be radially spaced from the radial center axis of the tubular element by at least 10% of the diameter of the end wall. The geometric center of the opening may be radially spaced from the radial center axis of the tubular element by at least 15% of the diameter of the end wall. The geometric center of the opening may be radially spaced from the radial center axis of the tubular element by at least 20% of the diameter of the end wall. The geometric center of the opening may be radially spaced from the radial center axis of the tubular element by at least 25% of the diameter of the end wall. The geometric center of the opening may be radially spaced from the radial center axis of the tubular element by at least 30% of the diameter of the end wall.

[0037] The opening may coincide with the perimeter of the end wall. For example, the perimeter of the end wall may form at least a portion of the perimeter of the opening. This means that the opening is immediately adjacent to the tubular wall of the tubular element. Advantageously, this allows air and volatile compounds flowing through the opening to come into close contact with the tubular wall of the tubular element, thereby increasing heat transfer between the air, volatile compounds, and the tubular wall.

[0038] The term "equivalent diameter" of an opening is used herein to mean the diameter of a circular opening having the same cross-sectional area as the opening.

[0039] The opening may have an equivalent diameter of about 0.5 mm to about 5 mm. The opening may have an equivalent diameter of about 0.8 mm to about 3 mm. The opening may have an equivalent diameter of about 1 mm to about 2 mm. The opening may have an equivalent diameter of about 2 mm to about 3 mm. The opening may have a diameter of about 0.5 mm to about 5 mm.

[0040] The opening may have an equivalent diameter of at least about 0.5 mm. The opening may have an equivalent diameter of at least about 0.8 mm. The opening may have an equivalent diameter of at least about 1 mm. The opening may have an equivalent diameter of at least about 1.5 mm. The opening may have an equivalent diameter of at least about 2 mm. The opening may have an equivalent diameter of at least about 2.5 mm. The opening may have an equivalent diameter of at least about 3 mm.

[0041] The opening may have an equivalent diameter of no more than about 5 mm. The opening may have an equivalent diameter of no more than about 3 mm. The opening may have an equivalent diameter of no more than about 2 mm.

[0042] The opening may have an equivalent diameter equal to or greater than 10% of the diameter of the end wall. The opening may have an equivalent diameter equal to or greater than 20% of the diameter of the end wall. The opening may have an equivalent diameter equal to or greater than 30% of the diameter of the end wall. The opening may have an equivalent diameter equal to or greater than 40% of the diameter of the end wall. The opening may have an equivalent diameter equal to or greater than 50% of the diameter of the end wall.

[0043] The opening may have an equivalent diameter of about 7% to about 70% of the diameter of the end wall. The opening may have an equivalent diameter of about 11% to about 45% of the diameter of the end wall. The opening may have an equivalent diameter of about 13% to about 27% of the diameter of the end wall. The opening may have an equivalent diameter of about 27% to about 42% of the diameter of the end wall.

[0044] The opening may have an equivalent diameter of at least about 7% of the diameter of the end wall. The opening may have an equivalent diameter of at least about 10% of the diameter of the end wall. The opening may have an equivalent diameter of at least about 11% of the diameter of the end wall. The opening may have an equivalent diameter of at least about 13% of the diameter of the end wall.

[0045] The opening may have an equivalent diameter of no more than about 70% of the diameter of the end wall. The opening may have an equivalent diameter of no more than about 45% of the diameter of the end wall. The opening may have an equivalent diameter of no more than about 42% of the outer diameter of the end wall. The opening may have an equivalent diameter of no more than about 30% of the diameter of the end wall. The opening may have an equivalent diameter of no more than about 27% of the diameter of the end wall.

[0046] The end wall may include a central region coaxial with the radial center axis of the tubular element. The end wall may include a peripheral region defining the central region. The peripheral region may be defined by a periphery of the central region and a periphery of the end wall. The central region may be circular in shape. The central region may be air-impermeable. The opening may be defined in the peripheral region.

[0047] The central region may have a diameter equal to or greater than 70% of the diameter of the end wall. The central region may have a diameter equal to or greater than 60% of the diameter of the end wall. The central region may have a diameter equal to or greater than 50% of the diameter of the end wall. The central region may have a diameter equal to or greater than 40% of the diameter of the end wall. The central region may have a diameter equal to or greater than 30% of the diameter of the end wall. The central region may have a diameter equal to or greater than 20% of the diameter of the end wall. The central region may have a diameter equal to or greater than 10% of the diameter of the end wall.

[0048] In some embodiments, the cross-sectional area of the central region is equal to the cross-sectional area of the peripheral region.

[0049] As will be described in more detail below, the aerosol-generating article may further include ventilation zones at locations along the tubular element. Advantageously, this can increase the cooling of the air and volatile compounds within the interior of the tubular element by drawing in cooler outside air. It can also increase turbulence within the tubular element, particularly if the ventilation zones cause air to be drawn into the tubular element in a direction transverse to the longitudinal axis of the tubular element.

[0050] The tubular element may include a first end and a second end positioned opposite the first end. The end wall may be a first end wall formed by a first folded end portion. The first end wall may be positioned at the first end of the tubular element. The tubular element may include a second end wall formed by a second folded end portion. The second end wall may be positioned at the second end of the tubular element. The second end wall may define an opening for fluidly connecting the interior of the tubular element and the exterior of the tubular element. The opening defined by the second end wall may have an equivalent diameter that is smaller than the equivalent diameter of the opening defined in the first end wall. Alternatively, the opening defined by the second end wall may have an equivalent diameter that is larger than the equivalent diameter of the opening defined in the first end wall.

[0051] As will be described in more detail below, the first element may further comprise a susceptor element. The susceptor element may be positioned at a radially central position within the aerosol-forming substrate. The susceptor element may extend along the radial central axis of the aerosol-forming substrate. In this configuration, the opening may be radially spaced apart from the susceptor element. For example, the opening and the susceptor element may be positioned such that, when the aerosol-generating article is viewed parallel to the longitudinal direction of the aerosol-generating article, a cross-section of the susceptor element does not overlap with a cross-section of the opening. Alternatively, the opening and the susceptor element may be positioned such that, when the aerosol-generating article is viewed parallel to the longitudinal direction of the aerosol-generating article, a cross-section of the susceptor element partially, but not completely, overlaps with a cross-section of the opening. For example, the cross-section of the susceptor element may overlap by less than 50% of the cross-section of the opening. Preferably, less than 40%, more preferably less than 30%. Most preferably, less than 20%.

[0052] Because the opening is offset relative to the radial center axis, the aerosol generated in the aerosol-forming substrate, such as an aerosol generated near the radial center axis, can move radially outwards when the aerosol is drawn through the aerosol-forming substrate. This is particularly advantageous in embodiments in which a heat source is positioned at a radially central position within the aerosol-forming substrate, such as the above-mentioned susceptor element or heating element of a device that is inserted into the substrate during use. Typically, in such embodiments, the peripheral portion of the substrate is cooler than the radial center portion of the substrate. Therefore, as the aerosol moves radially outwards within the aerosol-forming substrate, the aerosol can cool. When most of the aerosol can be formed near the heat source, this can be particularly beneficial during the user's first puff on the article.

[0053] The tubular element may define a lumen. The lumen may extend from a first end of the tubular element to a second end of the tubular element. For example, the lumen may extend from an upstream end of the tubular element to a downstream end of the tubular element. The lumen may be the interior of the tubular element. The lumen may be substantially empty. Advantageously, an empty lumen allows for unimpeded flow within the tubular element.

[0054] The cavity may have a cross-sectional area that is at least 70% of the cross-sectional area of the end wall. The cavity may have a cross-sectional area that is at least 80% of the cross-sectional area of the end wall. The cavity may have a cross-sectional area that is at least 90% of the cross-sectional area of the end wall. The cavity may have a cross-sectional area that is at least 95% of the cross-sectional area of the end wall.

[0055] The tubular element can be formed from a paper material, such as paper, paperboard, or cardboard. The tubular element can be formed from multiple overlapping paper layers, such as multiple parallel-wound paper layers or multiple spirally-wound paper layers. Forming the tubular element from multiple overlapping paper layers can help improve the tubular element's resistance to collapse or deformation while still allowing the end wall to be formed from the folded end portion of the tubular element.

[0056] The aerosol-generating article may comprise a plurality of elements assembled in the form of a strip.The plurality of elements may comprise a first element and a tubular element.

[0057] The aerosol-generating article may comprise an outer wrapper that defines at least a tubular element. The outer wrapper may define the outer surface of the aerosol-generating article. The outer wrapper may also define a first element. The outer wrapper may define all of a plurality of elements of the aerosol-generating article assembled in the form of a strip. As described below, the outer wrapper may be a tipping wrapper. The outer wrapper that defines the tubular element may be a paper wrapper or a non-paper wrapper. Suitable paper wrappers for use in particular embodiments of the present invention are known in the art and include, but are not limited to, cigarette papers; and filter segment wrappers. Suitable non-paper wrappers for use in particular embodiments of the present invention are known in the art and include, but are not limited to, sheets of homogenized tobacco material. In certain preferred embodiments, the outer wrapper may be formed from a laminate comprising a plurality of layers. Preferably, the wrapper is formed from an aluminum co-laminated sheet. In situations where the aerosol-forming substrate should be ignited rather than heated in the intended manner, the use of a co-laminated sheet comprising aluminum advantageously prevents combustion of the outer wrapper.

[0058] The end wall may extend substantially transversely to the longitudinal direction of the aerosol-generating article.The end wall may extend substantially transversely to the longitudinal direction of the tubular element.

[0059] In another embodiment, the end wall of tubular element is provided with a plurality of end portions which extend into the tubular element. The end wall can partially extend into the inside of the tubular element. The end wall can form an angle less than 90 degrees with the inner surface of the tubular element, more preferably form an angle less than 80 degrees with the inner surface of the tubular element, even more preferably form an angle less than 70 degrees with the inner surface of the tubular element. This can be achieved by ensuring that folding force is applied to the tubular element during the manufacture of the tubular element so that at least a portion of the first end portion of the tubular element is pushed into the inside of the tubular element. This type of arrangement can advantageously increase the possibility that the end wall remains stationary relative to the tubular element after having manufactured the tubular element. Especially, this type of arrangement can help to overcome any natural elasticity in the material forming the tubular element so that the folded end portion of the tubular element is unlikely to recover towards its folded front state after manufacture.

[0060] The end wall may extend from a fold point on the tubular element and towards a radially central location of the tubular element.

[0061] Preferably, the material forming the end wall is substantially air impermeable. The material forming the end wall may have a porosity of less than 2000 Coresta units. The material forming the end wall may have a porosity of less than 1000 Coresta units. The material forming the end wall may have a porosity of less than 500 Coresta units.

[0062] The tubular element may have an outer diameter substantially equal to the outer diameter of the aerosol-generating article.Preferably, the tubular element has an outer diameter substantially equal to the outer diameter of the first element.

[0063] The tubular element may have an outer diameter between 5 mm and 11 mm. The outer diameter of the tubular element may be between 6 mm and 10 mm, for example, between 7 mm and 9 mm, or between 7.5 mm and 8.5 mm. In a preferred embodiment, the tubular element has an outer diameter of 7.8 mm + / - 10%. In another preferred embodiment, the tubular element has an outer diameter of 6 mm + / - 10%.

[0064] Preferably, the tubular element has an equivalent inner diameter of at least about 5.5 millimeters. More preferably, the tubular element has an equivalent inner diameter of at least about 6 millimeters. Even more preferably, the tubular element has an equivalent inner diameter of at least about 7 millimeters. The term "equivalent inner diameter" is used herein to represent the diameter of a circle having the same surface area as the cross-section of the airflow conduit defined within the tubular element. The cross-section of the airflow conduit can have any suitable shape. However, as briefly described above, a circular cross-section is preferred, that is, the tubular element is actually a cylindrical tube. In this case, the equivalent inner diameter of the tubular element effectively coincides with the inner diameter of the cylindrical tube.

[0065] The equivalent inner diameter of the tubular element is preferably less than about 10 mm. More preferably, the equivalent inner diameter of the tubular element is less than about 9.5 mm, even more preferably less than 9 mm.

[0066] Preferably, the wall thickness of the tubular element is at least about 0.1 mm, more preferably at least about 0.2 mm.

[0067] Preferably, the wall thickness of the tubular element is less than about 1.5 mm, preferably less than about 1.25 mm. In a preferred embodiment, the tubular element has a wall thickness of less than about 1 mm.

[0068] Thus, the wall thickness of the tubular element is preferably between about 0.1 mm and about 1.5 mm, or between about 0.2 mm and about 1.25 mm, or between about 0.5 mm and about 1 mm.

[0069] Providing the tubular element with such a wall thickness can help improve the tubular element's resistance to collapse or deformation, while still enabling the end walls to be formed from the folded end portions of the tubular element.

[0070] Preferably, the length of the tubular element is at least about 10 mm, more preferably at least about 15 mm.

[0071] Preferably, the length of the tubular element is less than about 30 mm, preferably less than about 25 mm, even more preferably less than about 20 mm.

[0072] The length of the tubular element can be from about 10 mm to about 30 mm, preferably from about 15 mm to about 25 mm, more preferably from about 15 mm to about 20 mm. For example, in a particularly preferred embodiment, the tubular element has a length of 18 mm.

[0073] The length of the tubular element can be from about 5 mm to about 20 mm, preferably from about 8 mm to about 15 mm, more preferably from about 10 mm to about 13 mm. For example, in a particularly preferred embodiment, the tubular element has a length of 12 mm.

[0074] Preferably, the tubular element is adapted to generate an RTD between about 0 mm H2O and about 80 mm H2O, more preferably between about 20 mm H2O and about 70 mm H2O, and even more preferably between about 30 mm H2O and about 70 mm H2O. For example, the tubular element may be adapted to generate an RTD between about 35 mm H2O and about 70 mm H2O.

[0075] The tubular element may be adapted to generate an RTD between about 0 mm H2O and about 20 mm H2O, more preferably between about 0 mm H2O and about 10 mm H2O.

[0076] The tubular element may comprise at least two paper layers.The tubular element may comprise fewer than eleven paper layers.

[0077] Where the tubular element is formed from a paper material, the paper material may have a basis weight of at least about 90 grams per square meter. The paper material may have a basis weight of less than about 300 grams per square meter. The paper material may have a basis weight of about 100 to about 200 grams per square meter. Providing the tubular element with such a wall basis weight may help improve the tubular element's resistance to collapse or deformation while still enabling the end wall to be formed from the folded end portion of the tubular element.

[0078] The end wall of the tubular element may comprise a hydrophobic region comprising hydrophobic groups covalently bonded to the end wall.Where the tubular element comprises a second end wall, the second end wall may also comprise a hydrophobic region.

[0079] 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 / m2 or less, or about 35 g / m2 or less.

[0080] The hydrophobic region can be produced by a process comprising applying a liquid composition comprising a fatty acid halide to the surface of the end wall and maintaining the surface at a temperature of about 120 degrees C. to about 180 degrees C. The fatty acid halide reacts in situ with the proton groups of the material in the hydrophobic region, resulting in the formation of fatty acid esters.

[0081] The term "hydrophobicity" refers to the property of a surface to repel water. A useful method for determining this is to measure the water contact angle. The "water contact angle" is the angle, conventionally measured, made by a liquid when a liquid / vapor interface encounters a solid surface. It quantifies the wettability of a solid surface by a liquid via Young's equation.

[0082] The hydrophobic region has a Cobb Water Absorption (ISO 535:1991) value (at 60 seconds) of less than about 40 g / m2, less than about 35 g / m2, less than about 30 g / m2, or less than about 25 g / m2.

[0083] The water contact angle of the hydrophobic region is 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 using the TAPPI T558 om-97 test, and the results are presented as the interfacial contact angle and reported in degrees, and can range from approximately zero to approximately 180 degrees. When the contact angle is not specified along with the term hydrophobicity, the water contact angle is at least 90 degrees.

[0084] The aerosol-generating article may comprise a downstream section located at a position downstream from the first element.The downstream section may comprise one or more downstream elements, such as a tubular element.

[0085] The aerosol-generating article may include a mouthpiece element. The downstream section may include a mouthpiece element. The mouthpiece element may be positioned downstream of the tubular element. The mouthpiece element may be positioned immediately downstream of the tubular element. The mouthpiece element may be adjacent to the downstream end of the tubular element. The mouthpiece element may extend all the way to the mouth end of the aerosol-generating article. The mouthpiece element may extend from the downstream end of the tubular element to the mouth end of the aerosol-generating article.

[0086] The mouthpiece element may comprise at least one mouthpiece filter segment for filtering aerosols generated by the aerosol-forming substrate. For example, the mouthpiece element may comprise one or more segments of fibrous filter material. Suitable fibrous filter materials will be known to the skilled person. Preferably, at least one mouthpiece filter segment comprises a cellulose acetate filter segment formed from cellulose acetate tow.

[0087] The mouthpiece element may be comprised of a single mouthpiece filter segment.In an alternative embodiment, the mouthpiece element comprises two or more mouthpiece filter segments axially aligned with each other in an abutting end-to-end relationship.

[0088] The mouthpiece element may comprise a mouth end cavity. The mouth end cavity may be defined by a hollow tubular element provided at the downstream end of the mouthpiece. Alternatively, the mouth end cavity may be defined by the outer wrapper of the aerosol-generating article at the mouth end.

[0089] The mouthpiece element may include flavorings. The flavorings may be provided in any suitable form. For example, the mouthpiece element may include one or more capsules, beads or particles of flavorings, or one or more threads or wires loaded with flavorings.

[0090] Preferably, the mouthpiece element has a low particle filtration efficiency.

[0091] Preferably, the mouthpiece is formed from sections of fibrous filter material.

[0092] Preferably, the mouthend element is defined by a filter segment wrapper.Preferably, the mouthend element is non-ventilated, such that air does not enter the aerosol-generating article through the mouthend element.

[0093] The mouthend element may be connected to one or more of the adjacent upstream components of the aerosol-generating article, such as the tubular element, by means of a tipping wrapper.

[0094] Preferably, the mouthpiece element has an RTD of less than about 25 mm H2 O. More preferably, the mouthpiece element has an RTD of less than about 20 mm H2 O. Even more preferably, the mouthpiece element has an RTD of less than about 15 mm H2 O.

[0095] RTD values of about 10 mm H2O to about 15 mm H2O are particularly preferred, as a mouthpiece element having such an RTD is expected to contribute minimally to the overall RTD of the aerosol-generating article and to exert substantially no filtering effect on the aerosol delivered to the consumer.

[0096] The mouthpiece element may have an outer diameter approximately equal to the outer diameter of the aerosol-generating article. The mouthpiece element may have an outer diameter between about 5 mm and about 10 mm, or between about 6 mm and about 8 mm. In a preferred embodiment, the mouthpiece element has an outer diameter of about 7.2 mm.

[0097] The length of the mouthpiece element may be at least about 10 mm, more preferably at least about 11 mm, more preferably at least about 12 mm. The length of the mouthpiece element may be less than about 25 mm, more preferably less than about 20 mm, more preferably less than about 15 mm.

[0098] The length of the mouthpiece element may be from about 10 mm to about 25 mm, more preferably from about 10 mm to about 20 mm, even more preferably from about 10 mm to about 15 mm. The length of the mouthpiece element may be from about 11 mm to about 25 mm, more preferably from about 11 mm to about 20 mm, even more preferably from about 11 mm to about 15 mm. The length of the mouthpiece element may be from about 12 mm to about 25 mm, more preferably from about 12 mm to about 20 mm, even more preferably from about 12 mm to about 20 mm.

[0099] In a preferred embodiment, the mouthend element has a length of approximately 12 mm.

[0100] Providing a relatively long mouthend element in an aerosol-generating article may allow for the inclusion of a pouch, or allow the article to be more rigid at the point where the user applies the lips, or both.

[0101] The aerosol-generating article may include a ventilation zone at a location along the downstream section. The ventilation zone may be provided at a location along the tubular element. The features of the ventilation zone are described below with respect to the aerosol-generating article. However, it will be appreciated that they may also be applied directly to the tubular element itself.

[0102] The ventilation zone may be positioned between about 5 mm and about 15 mm from the folded end portion of the tubular element. The ventilation zone may be positioned at least 2 mm from the folded end portion of the tubular element, more preferably at least 3 mm from the folded end portion of the tubular element, and even more preferably at least 5 mm from the folded end portion of the tubular element.

[0103] The ventilation zone may be located less than 20 mm from the folded end portion of the tubular element, more preferably less than 15 mm from the folded end portion of the tubular element, even more preferably less than 10 mm from the folded end portion of the tubular element.

[0104] The ventilation zone may be located in the downstream section of the tubular element. Preferably, the ventilation zone is positioned between about 1 mm and about 10 mm from the downstream end of the tubular element, more preferably between about 2 mm and about 8 mm from the downstream end of the tubular element, and even more preferably between about 3 mm and about 6 mm from the downstream end of the first tubular element.

[0105] The ventilation zone may be located at least 1 mm from the downstream end of the tubular element, more preferably the ventilation zone is located at least 2 mm from the downstream end of the tubular element, even more preferably the ventilation zone is located at least 3 mm from the downstream end of the tubular element.

[0106] The ventilation zone may be located less than 10 mm from the downstream end of the tubular element, more preferably less than 8 mm from the downstream end of the tubular element, even more preferably less than 6 mm from the downstream end of the tubular element.

[0107] The ventilation zone may comprise a plurality of perforations extending through the circumferential wall of the ventilated element, which may be a tubular element. Preferably, the ventilation zone comprises at least one row of circumferential perforations. The ventilation zone may comprise two rows of circumferential perforations. For example, the perforations may be formed during manufacture of the aerosol-generating article. Preferably, each row of circumferential perforations comprises 8 to 30 perforations.

[0108] Aerosol-generating articles according to the present invention may have a ventilation level of at least about 5%.

[0109] Throughout this specification, the term "ventilation level" is used to denote the volume ratio of the airflow entering 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 more diluted the aerosol flow delivered to the consumer.

[0110] Aerosol-generating articles may typically have a ventilation level of at least about 10%, preferably at least about 15%, more preferably at least about 20%.

[0111] In a preferred embodiment, 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 may have a ventilation level of less than or equal to about 45%. More preferably, the aerosol-generating article may have a ventilation level of less than or equal to about 40%, even more preferably less than or equal to about 35%.

[0112] In a particularly preferred embodiment, the aerosol-generating article has a ventilation level of about 30%. The ventilation level of the aerosol-generating article may be from about 20% to about 60%, preferably from about 20% to about 45%, more preferably from about 20% to about 40%. The ventilation level of the aerosol-generating article may be from about 25% to about 60%, preferably from about 25% to about 45%, more preferably from about 25% to about 40%. In another embodiment, the aerosol-generating article has a ventilation level of from about 30% to about 60%, preferably from about 30% to about 45%, more preferably from about 30% to about 40%.

[0113] 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%.

[0114] Embodiments in which the ventilation zone is disposed at a location along the tubular element can provide a number of advantages. For example, and without wishing to be bound by theory, the inventors have discovered that the temperature drop caused by cooler outside air entering the tubular element via the ventilation zone can have a beneficial effect on the nucleation and growth of aerosol particles.

[0115] Aerosol formation from gas mixtures containing various chemical species depends on a delicate interplay of nucleation, evaporation, condensation, and coalescence, taking into account variations in vapor concentration, temperature, and the velocity field. The so-called classical nucleation theory is based on the assumption that a fraction of molecules in the vapor phase are large enough to remain coherent for extended periods with sufficient probability (e.g., half the probability). These molecules represent a critical, threshold molecular cluster within the transient molecular aggregate, meaning that, on average, smaller clusters are likely to quickly disintegrate into the vapor phase, while larger clusters are likely to grow. This critical cluster is considered the key nucleation core from which droplets are expected to grow due to condensation of molecules from the vapor. Assuming that the newly nucleated droplet begins with a certain initial diameter, it may then grow by several orders of magnitude. This process is facilitated and enhanced by condensation caused by rapid cooling of the surrounding vapor. In this regard, it is important to remember that evaporation and condensation are two aspects of the same mechanism: gas-liquid mass transfer. While evaporation involves a net mass transfer from the droplet to the vapor phase, condensation involves a net mass transfer from the vapor phase to the droplet phase. Evaporation (or condensation) will cause the droplet to shrink (or grow) but will not change its population.

[0116] 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 behaviors associated with the formation of the liquid phase (droplets), as the nucleation process is generally nonlinear. Without wishing to be bound by theory, it is hypothesized that cooling can lead to a rapid increase in the number concentration of droplets, followed by a strong, short-lived increase in this growth (a nucleation burst). This nucleation burst appears to be more pronounced at lower temperatures. Furthermore, it appears that higher cooling rates may favor an earlier onset of nucleation. In contrast, a reduction in the cooling rate appears to have a favorable effect on the final size ultimately achieved by the aerosol droplets.

[0117] Therefore, the rapid cooling caused by the entry of external air into the tubular element via the ventilation zone can be advantageously used to promote the nucleation and growth of aerosol droplets.However, at the same time, letting external air into the tubular element has the direct disadvantage of diluting the aerosol flow delivered to the consumer.

[0118] The present inventors have surprisingly discovered that when ventilation levels are within the above-mentioned ranges, the dilution effect on the aerosol (particularly as assessed by measuring the effect on the delivery of an aerosol-forming agent (such as glycerol) contained in the aerosol-forming substrate) is advantageously minimized. In particular, ventilation levels between 25% and 50%, and even more preferably between 28% and 42%, have been found to produce particularly satisfactory glycerol delivery values. At the same time, the degree of nucleation, and therefore the delivery of nicotine and aerosol-forming agent (e.g., glycerol), is enhanced.

[0119] The present inventors have unexpectedly discovered how the beneficial effect of enhanced nucleation facilitated by the rapid cooling caused by the introduction of ventilation air into the article can significantly offset the less desirable dilution effect. Thus, satisfactory aerosol delivery values are consistently achieved with aerosol-generating articles according to the present disclosure.

[0120] This is particularly advantageous for "short" aerosol-generating articles, such as aerosol-generating articles in which the length of the first element comprising the aerosol-forming substrate is less than about 40 mm, preferably less than 25 mm, even more preferably less than 20 mm, or in which the overall length of the aerosol-generating article is less than about 70 mm, preferably less than about 60 mm, even more preferably less than 50 mm. As will be appreciated, in such aerosol-generating articles there is little time and space for the aerosol to form and for the particle phase of the aerosol to become available for delivery to a consumer.

[0121] Furthermore, because the vented tubular element can be configured to make substantially no contribution to the overall RTD of the aerosol-generating article, in such an aerosol-generating article, the overall RTD of the article can be advantageously fine-tuned by adjusting the length and density of the first element comprising the aerosol-forming substrate, or the length and optionally the length and density of the filter material segment forming part of the mouthpiece element, or the length and density of an element disposed upstream of the first element comprising the aerosol-forming substrate. Thus, aerosol-generating articles having a predetermined RTD can be manufactured consistently and with high precision, such that a satisfactory RTD level can be provided to consumers even in the presence of ventilation.

[0122] Furthermore, the inventors have discovered that enhanced mixing of heated air from the aerosol-forming substrate with fresh air from the ventilation system drawn through the ventilation apertures can be achieved when ventilation is provided to a tubular element, the tubular element comprising an end wall formed by a folded end portion of the tubular element, wherein the end wall defines an opening for fluidly connecting an interior of the tubular element with an exterior of the tubular element. In particular, and without wishing to be bound by theory, it is believed that the partial airflow restriction created by the end wall, combined with the presence of incoming air from the ventilation system, can be particularly effective in promoting mixing of heated air drawn through the aerosol-forming substrate with fresh air drawn through the ventilation apertures.

[0123] The aerosol-generating article may further comprise an upstream section located upstream of the first element. The upstream section may comprise one or more upstream elements, such as tubular elements according to the present invention. In other words, the aerosol-generating article may comprise a first tubular element according to the present invention located downstream of the first element and a second tubular element according to the present invention located upstream of the first element.

[0124] The first element comprising the aerosol-forming substrate may further comprise a susceptor element positioned within the aerosol-forming substrate. The susceptor element may be an elongated susceptor element. The susceptor element may extend longitudinally within the aerosol-forming substrate. The susceptor element is configured to be in thermal contact with the aerosol-forming substrate.

[0125] As used herein, the term "susceptor element" refers to a material that can convert electromagnetic energy into heat. When placed in a fluctuating electromagnetic field, eddy currents induced in the susceptor element cause the susceptor element to heat. When the elongated susceptor element is placed in thermal contact with an aerosol-forming substrate, the aerosol-forming substrate is heated by the susceptor element.

[0126] The term "elongated" when used to describe a susceptor element means that the length dimension of the susceptor element is greater than its width dimension or its thickness dimension, such as greater than twice its width dimension or its thickness dimension.

[0127] The susceptor element may be arranged substantially longitudinally within the aerosol-forming substrate. This means that the length dimension of the elongate susceptor element is arranged substantially parallel to the longitudinal direction of the aerosol-forming substrate, for example within plus or minus 10 degrees of parallel to the longitudinal direction of the aerosol-forming substrate. In a preferred embodiment, the elongate susceptor element may be positioned at a radially central position within the aerosol-forming substrate and extend along the longitudinal axis of the aerosol-forming substrate.

[0128] In embodiments where the aerosol-generating article is in the form of a strip, the susceptor element is arranged substantially longitudinally within the strip. This means that the length dimension of the elongate susceptor element is arranged approximately parallel to the longitudinal direction of the strip, for example within plus or minus 10 degrees of parallel to the longitudinal direction of the strip. In preferred embodiments, the elongate susceptor element may be positioned at a radially central position within the strip and extend along the longitudinal axis of the strip.

[0129] Preferably, the susceptor element extends all the way to the downstream end of the first element. The susceptor element may extend all the way to the upstream end of the first element. In a particularly preferred embodiment, 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.

[0130] The susceptor element is preferably in the form of a pin, bar, strip or blade.

[0131] The susceptor element preferably has a length of about 5 mm to about 15 mm, such as about 6 mm to about 12 mm, or about 8 mm to about 10 mm.

[0132] The ratio between the length of the susceptor element and the overall length of the aerosol-generating article may be from about 0.2 to about 0.35.

[0133] Preferably, the ratio of the length of the susceptor element to the overall length of the aerosol-generating article is at least about 0.22, more preferably at least about 0.24, even more preferably at least about 0.26. The ratio of the length of the susceptor element to the overall length of the aerosol-generating article is preferably less than about 0.34, more preferably less than about 0.32, even more preferably less than about 0.3.

[0134] The ratio of the length of the susceptor element to the overall length of the aerosol-generating article may 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 of the length of the susceptor element to the overall length of the aerosol-generating article may 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 of the length of the susceptor element to the overall length of the aerosol-generating article 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.

[0135] In particularly preferred embodiments, the ratio of the length of the susceptor element to the overall length of the aerosol-generating article is about 0.27.

[0136] The susceptor element preferably has a width of about 1 mm to about 5 mm.

[0137] The susceptor element may typically have a thickness of about 0.01 mm to about 2 mm, such as about 0.5 mm to about 2 mm. The thickness of the susceptor element may be about 10 microns to about 500 microns, more preferably about 10 microns to about 100 microns.

[0138] If the susceptor element has a constant cross-section, such as a circular cross-section, it has a preferred width or diameter of about 1 mm to about 5 mm.

[0139] If the susceptor element is in the form of a strip or blade, the strip or blade preferably has a rectangular shape with a width of preferably about 2 mm to about 8 mm, more preferably about 3 mm to about 5 mm. For example, the susceptor element in the form of a strip or blade may have a width of about 4 mm.

[0140] If the susceptor element is in the form of a strip or blade, the strip or blade preferably has a rectangular shape and a thickness of about 0.03 mm to about 0.15 mm, more preferably about 0.05 mm to about 0.09 mm. For example, the susceptor element in the form of a strip or blade may have a thickness of about 0.07 mm.

[0141] In a preferred embodiment, the elongated susceptor elements are in the form of strips or blades, preferably having a rectangular shape, and having a thickness of about 55 microns to about 65 microns.

[0142] More preferably, the elongated susceptor element has a thickness of about 57 microns to about 63 microns. Even more preferably, the elongated susceptor element has a thickness of about 58 microns to about 62 microns. In a particularly preferred embodiment, the elongated susceptor element has a thickness of about 60 microns.

[0143] Preferably, the elongate susceptor element has a length that is the same as or shorter than the length of the aerosol-forming substrate.Preferably, the elongate susceptor element has the same length as the aerosol-forming substrate.

[0144] The susceptor element may be formed from any material that can be heated inductively to a temperature sufficient to generate an aerosol from the aerosol-forming substrate.Preferably the susceptor element comprises metal or carbon.

[0145] Preferred susceptor elements may include or be composed of ferromagnetic materials, such as ferromagnetic alloys, ferritic iron, or ferromagnetic steel or stainless steel. Suitable susceptor elements may be or include aluminum. Preferred susceptor elements may be formed from 400 series stainless steel, such as 410 grade, 420 grade, or 430 grade stainless steel. Different materials will dissipate different amounts of energy when placed within an electromagnetic field having similar frequency and field strength values.

[0146] Thus, parameters of the susceptor element such as material type, length, width and thickness may all be modified to provide the desired power dissipation within a known electromagnetic field.Preferred susceptor elements may be heated to temperatures in excess of 250 degrees Celsius.

[0147] Suitable susceptor elements may include a non-metallic core having a metallic layer disposed on the non-metallic core, such as a metal track formed on the surface of a ceramic core. The susceptor element may have an outer protective layer, such as a ceramic protective layer or a glass protective layer, encapsulating the susceptor element. The susceptor element may include a protective coating formed of glass, ceramic, or an inert metal formed on the core of the susceptor element material.

[0148] The susceptor element is arranged in thermal contact with the aerosol-forming substrate. Thus, when the susceptor element heats up, the aerosol-forming substrate heats up and an aerosol is formed. Preferably, the susceptor element is arranged in direct physical contact with the aerosol-forming substrate, for example within the aerosol-forming substrate.

[0149] The susceptor element may be a multi-material susceptor element and may include a first susceptor element material and a second susceptor element material. The first susceptor element material is placed in close 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 preferably serves primarily to heat the susceptor element when placed in a fluctuating electromagnetic field. Any suitable material may be used. For example, the first susceptor element material may be aluminum, or may be a ferrous material such as stainless steel. The second susceptor element material preferably serves primarily to indicate when the susceptor element has reached a specific 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 entire susceptor element during operation. Therefore, the Curie temperature of the second susceptor element material should be below the ignition point of the aerosol-forming substrate. Suitable materials for the second susceptor element material may include nickel and certain nickel alloys.

[0150] By providing a susceptor element having at least a first susceptor element material and a second susceptor element material, wherein the second susceptor element material has a Curie temperature and the first susceptor element material does not have a Curie temperature, or wherein the first susceptor element material and the second susceptor element material have first and second Curie temperatures that differ from each other, heating of the aerosol-forming substrate and temperature control of the heating can be separated. The first susceptor element material is preferably a magnetic material having a Curie temperature of 500 degrees Celsius or greater. From the perspective of heating efficiency, it is desirable that the Curie temperature of the first susceptor element material be above any maximum temperature to which the susceptor element should be heated. The second Curie temperature may preferably be selected to be less than 400 degrees Celsius, preferably less than 380 degrees Celsius, or less than 360 degrees Celsius. Preferably, the second susceptor element material is a magnetic material selected to have a second Curie temperature that is substantially the same as the desired maximum heating temperature. That is, preferably, the second Curie temperature is approximately the same as the temperature to which the susceptor element should be heated in order to generate an aerosol from the aerosol-forming substrate. The second Curie temperature may, for example, be in the range of 200 to 400 degrees Celsius, or between 250 and 360 degrees Celsius. The second Curie temperature of the second susceptor element material may, for example, be selected such that the bulk average temperature of the aerosol-forming substrate does not exceed 240 degrees Celsius after being heated by the susceptor element at a temperature equal to the second Curie temperature.

[0151] The aerosol-forming substrate may be in the form of a strip.The aerosol-forming substrate may be a solid aerosol-forming substrate.

[0152] In certain preferred embodiments, the aerosol-forming substrate comprises homogenised plant material, preferably homogenised tobacco material.

[0153] As used herein, the term "homogenized plant material" encompasses any plant material formed by the agglomeration of plant particles. For example, a sheet or web of homogenized tobacco material for use in the aerosol-forming substrate of the present invention may be formed by agglomerating particles of tobacco material obtained by comminuting, grinding or crushing plant material and optionally one or more of tobacco leaves and tobacco stems. Homogenized plant material may be produced by casting, extrusion, papermaking, or any other suitable process known in the art.

[0154] Homogenized plant material can be provided in any suitable form. For example, the homogenized plant material can be in the form of one or more sheets. As used herein, the term "sheet" describes a layered element whose width and length are substantially greater than its thickness. The homogenized plant material can be in the form of multiple pellets or particles. The homogenized plant material can be in the form of multiple strands, strips or fragments. As used herein, the term "strand" describes an elongated element material whose length is significantly greater than its width and thickness. The term "strand" should be considered to include strips, fragments and any other homogenized plant material with similar forms. The strand of the homogenized plant material can be formed by the sheet of the homogenized plant material, for example, by cutting or chopping, or by other methods, for example, by extrusion.

[0155] Due to the splitting or cracking of the homogenized plant material sheet during the formation of the aerosol-forming substrate, for example, due to curling, stock can be formed in situ in the aerosol-forming substrate. The homogenized plant material stocks in the aerosol-forming substrate can be separated from each other. At least some stocks of the homogenized plant material in the aerosol-forming substrate can be at least partially connected to adjacent one or more stocks along the length of the stock. For example, adjacent stocks can be connected by one or more fibers. As mentioned above, this can occur in the case of, for example, forming stocks due to the splitting of the sheet of the homogenized plant material during the production of the aerosol-forming substrate.

[0156] Preferably, the aerosol forming matrix is in the form of one or more sheets of homogenized plant material. One or more sheets of homogenized plant material can be produced by a casting process. One or more sheets of homogenized plant material can be produced by a papermaking process. As described herein, one or more sheets can each have a thickness between 100 microns and 600 microns, preferably between 150 microns and 300 microns and most preferably between 200 microns and 250 microns. Independent thickness refers to the thickness of an independent sheet, and combined thickness refers to the total thickness of all sheets constituting the aerosol forming matrix. For example, if the aerosol forming matrix is formed by two independent sheets, the combined thickness is the sum of the thickness of the two independent sheets or is the measured thickness of the two sheets when two sheets are stacked in the aerosol forming matrix.

[0157] One or more sheets as described herein may each individually have a grammage of from about 100 g / m2 to about 300 g / m2.

[0158] The one or more sheets described herein may each individually have a density of from about 0.3 g / cm3 to about 1.3 g / cm3, and preferably from about 0.7 g / cm3 to about 1.0 g / cm3.

[0159] In embodiments where the aerosol-forming substrate comprises one or more sheets of homogenised plant material, the sheets are preferably in the form of one or more aggregated sheets. As used herein, the term "aggregated" means that the sheets of homogenised plant material are rolled, folded or otherwise compressed or shrunk substantially transversely to the cylindrical axis of the rod or strip.

[0160] One or more sheets of homogenised plant material may be gathered transversely relative to their longitudinal axis and confined with a wrapper to form a continuous strip or stick.

[0161] One or more sheets of homogenized plant material may advantageously be curled or similarly treated. As used herein, the term "curled" means that the sheet has a plurality of substantially parallel ridges or ripples. Alternatively or in addition to curling, one or more sheets of homogenized plant material may be embossed, debossed, perforated, or otherwise deformed to provide texture on one or both sides of the sheet.

[0162] Preferably, each sheet of the homogenized plant material is curled so that it has a plurality of ridges or ripples that are substantially parallel to the cylindrical axis of the rod. This treatment advantageously promotes the gathering of the curled sheets of the homogenized plant material to form a rod. Preferably, one or more sheets of the homogenized plant material can be gathered. It should be appreciated that the curled sheets of the homogenized plant material may alternatively or additionally have a plurality of substantially parallel ridges or ripples that are arranged at an acute angle or an obtuse angle to the cylindrical axis of the rod. The sheet may be curled to a certain extent so that the integrity of the sheet is destroyed at the plurality of parallel ridges or ripples, thereby causing the material to separate and resulting in fragments, strands or strips of the homogenized plant material.

[0163] One or more sheets of homogenized plant material can be cut into stocks as described above. The aerosol-forming matrix can include a plurality of homogenized plant material stocks. Stock can be used to form a rod. Usually, the width of these stocks is about 5 millimeters, or about 4 millimeters, or about 3 millimeters, or about 2 millimeters or less. The length of stock can be greater than about 5 millimeters, between about 5 millimeters and about 15 millimeters, about 8 millimeters to about 12 millimeters, or about 12 millimeters. Preferably, stock has a length substantially identical to each other. The length of stock can be determined by manufacturing process, so that the bar is cut into shorter rods, and the length of stock corresponds to the length of rod. Stock may be fragile, which may cause fracture, especially during transportation. In this case, the length of some stocks may be less than the length of rod.

[0164] The plurality of strands preferably extend substantially longitudinally along the length of the aerosol-forming substrate, aligned with the longitudinal axis. Preferably, the plurality of strands are therefore aligned substantially parallel to one another.

[0165] The homogenized plant material may comprise up to about 95% by weight of plant particles on a dry weight basis. Preferably, the homogenized 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.

[0166] For example, the homogenized plant material can include between about 2.5% and about 95% by weight plant particles, or between about 5% and about 90% by weight plant particles, or between about 10% and about 80% by weight plant particles, or between about 15% and about 70% by weight plant particles, or between about 20% and about 60% by weight plant particles, or between about 30% and about 50% by weight plant particles on a dry weight basis.

[0167] The homogenized plant material can be a homogenized tobacco material comprising tobacco particles. The sheet of homogenized tobacco material for 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.

[0168] The term "tobacco particles" refers to particles of any plant member of the genus Nicotiana. The term "tobacco particles" refers to particles of ground or powdered tobacco leaves, ground or powdered tobacco stems, tobacco dust, tobacco fines, and other granular tobacco by-products formed during the processing, handling, and transportation of tobacco. In a preferred embodiment, tobacco particles are substantially all derived from tobacco leaves. By contrast, isolated nicotine and nicotine salts are compounds derived from tobacco, but are not considered to be tobacco particles for purposes of the present invention and are not included in the percentage of granular plant material.

[0169] Tobacco particles can be prepared from one or more tobacco plants. Any type of tobacco can be used in the blend. Examples of spendable tobacco types include, but are not limited to, sun-cured tobacco, flue-cured tobacco, burley tobacco, Maryland tobacco, Oriental tobacco, Virginia tobacco, and other specialty tobaccos.

[0170] Flue-curing 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 tobacco leaves turn yellow and wilt. During the second stage, the leaves are completely dried. During the third stage, the leaf stems are completely dried.

[0171] 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 large amounts of casing.

[0172] Oriental tobacco is a type of tobacco with small leaves and high aromatic qualities. However, the flavor of Oriental tobacco is milder than, for example, Burley tobacco. Therefore, a relatively small proportion of Oriental tobacco is typically used in tobacco blends.

[0173] 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 a mixture to produce tobacco particles. Therefore, the tobacco particles in the granular plant material can include a mixture of Kasturi tobacco and flue-cured tobacco.

[0174] 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, and most preferably at least about 4% by weight.

[0175] Homogenized plant material can comprise the tobacco particles that combines with the non-tobacco plant flavor particles.Preferably, the non-tobacco plant flavor particles are selected from one or more of the following: ginger particle, rosemary particle, eucalyptus particle, clove particle and anise particle.Preferably, in this type of embodiment, the homogenized plant material comprises with dry weight basis at least about 2.5 % by weight non-tobacco plant flavor particles, and wherein the remainder of plant particles is a tobacco particle.Preferably, the homogenized plant material comprises with dry weight basis at least about 4 % by weight non-tobacco plant flavor particles, more preferably at least about 6 % by weight non-tobacco plant flavor particles, more preferably at least about 8 % by weight non-tobacco plant flavor particles and more preferably at least about 10 % by weight non-tobacco plant flavor particles.Preferably, the homogenized plant material comprises with dry weight basis at least about 20 % by weight non-tobacco plant flavor particles, more preferably at most about 18 % by weight non-tobacco plant flavor particles, more preferably at most about 16 % by weight non-tobacco plant flavor particles.

[0176] The weight ratio of non-tobacco plant flavor particles and tobacco particles in the granular plant material forming the homogenized plant material can vary depending on the desired flavor profile and composition of the aerosol generated by the aerosol-forming substrate during use. Preferably, the homogenized plant material comprises, on a dry weight basis, at least a 1:30 weight ratio of non-tobacco plant flavor particles to tobacco particles, more preferably at least a 1:20 weight ratio of non-tobacco plant flavor particles to tobacco particles, more preferably at least a 1:10 weight ratio of non-tobacco plant flavor particles to tobacco particles, and most preferably at least a 1:5 weight ratio of non-tobacco plant flavor particles to tobacco particles.

[0177] The homogenised plant material preferably comprises no more than 95 wt% particulate plant material on a dry weight basis.Thus, the particulate plant material is typically combined with one or more further components to form the homogenised plant material.

[0178] The homogenized plant material may further comprise a binder to modify the mechanical properties of the granulated plant material, wherein the binder is included in the homogenized plant material during manufacture as described herein. Suitable exogenous 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.

[0179] The binder may be present in an amount of about 1 wt% to about 10 wt% based on the dry weight of the homogenized plant material, preferably in an amount of about 2 wt% to about 5 wt% based on the dry weight of the homogenized plant material.

[0180] The homogenized plant material may further include one or more lipids to facilitate diffusion of volatile components (e.g., aerosol formers, gingerol, 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 butter, shea butter, 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.

[0181] The homogenized plant material may further include a pH adjusting agent.

[0182] The homogenized plant material may further include fibers to modify 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; jute fibers and combinations thereof. Exogenous fibers derived from tobacco and / or ginger may also be added. Any fibers added to the homogenized plant material are not considered to form part of the "granular plant material" as defined above. Prior to inclusion in the homogenized plant material, the fibers may be treated by suitable methods known in the art, including but not limited to: mechanical pulping; refining; chemical pulping; bleaching; sulfate pulping; and combinations thereof. The fibers typically have a length greater than their width.

[0183] Suitable fibers generally have a length greater than 400 microns and less than or equal to 4 mm, preferably in the range of 0.7 mm to 4 mm. 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.

[0184] The homogenized plant material may further include one or more aerosol formers. Upon volatilization, the aerosol formers can transport other volatile compounds released from the aerosol-forming substrate upon heating, such as nicotine and flavorants, in the aerosol. Suitable aerosol formers for inclusion in the homogenized plant material are known in the art and include, but are not limited to: polyols, such as triethylene glycol, propylene glycol, 1,3-butylene glycol, and glycerol; esters of polyols, such as glycerol mono-, di-, or triacetate; and aliphatic esters of mono-, di-, or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate.

[0185] The homogenized plant material may have an aerosol-former content of between about 5% and about 30% by weight on a dry weight basis, such as 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.

[0186] 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 may preferably comprise an aerosol-forming agent 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-forming agent is preferably glycerol.

[0187] The homogenized plant material may have an aerosol-forming agent content of about 1% to 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-forming agent is retained in a reservoir separate from the substrate, the substrate may have an aerosol-forming agent content of greater than 1% and less than about 5%. In such embodiments, the aerosol-forming agent volatilizes upon heating, and the stream of aerosol-forming agent contacts the aerosol-forming substrate to entrain flavor from the aerosol-forming substrate in the aerosol.

[0188] The homogenized plant material may have an aerosol-forming agent content of about 30% to about 45% by weight. Such relatively high levels of aerosol-forming agent are particularly suitable for aerosol-forming substrates that are expected to be heated at temperatures below 275 degrees Celsius. In such embodiments, the homogenized plant material preferably further comprises between about 2% and about 10% by weight of cellulose ether on a dry weight basis and between about 5% and about 50% by weight of additional cellulose on a dry weight basis. It has been found that the use of a combination of cellulose ether and additional cellulose provides particularly effective aerosol delivery when used with an aerosol-forming substrate having an aerosol-forming agent content of between 30% and 45% by weight.

[0189] Suitable cellulose ethers include, but are not limited to, methylcellulose, hydroxypropylmethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, ethylhydroxyethylcellulose, and carboxymethylcellulose (CMC). In a particularly preferred embodiment, the cellulose ether is carboxymethylcellulose.

[0190] As used herein, term " additional cellulose " contains any cellulose material that is incorporated into the homogenizing plant material, and it is not derived from the non-tobacco plant particle or the tobacco particle that provide in the homogenizing plant material.Therefore, except non-tobacco plant material or tobacco material, additional cellulose is incorporated in the homogenizing plant material, as separates and different cellulose sources with any cellulose that provides inherently in non-tobacco plant particle or the tobacco particle.Additional cellulose will be derived from the plant different from non-tobacco plant particle or tobacco particle usually.Preferably, additional cellulose is the form of inert cellulose material, and described inert cellulose material is inert on the sense, and therefore does not influence the organoleptic properties that is formed by the aerosol matrix generation basically.For example, additional cellulose is preferably tasteless and odorless material.

[0191] The additional cellulose may include cellulose powder, cellulose fibers, or a combination thereof.

[0192] The aerosol-forming agent may act as a humectant in the aerosol-forming matrix.

[0193] The wrapper confining the strip of homogenised plant material may be a paper wrapper or a non-paper wrapper. Suitable paper wrappers for use in particular embodiments of the present invention are known in the art and include, but are not limited to: cigarette papers; and filter segment wrappers. Suitable non-paper wrappers for use in particular embodiments of the present invention are known in the art and include, but are not limited to, sheets of homogenised tobacco material. In certain preferred embodiments, the wrapper may be formed from a laminate comprising a plurality of layers. Preferably, the wrapper is formed from an aluminium co-laminated sheet. The use of a co-laminated sheet comprising aluminium advantageously prevents combustion of the aerosol-forming substrate in situations where the aerosol-forming substrate should be ignited rather than heated in the intended manner.

[0194] In some preferred embodiments, the aerosol-forming substrate comprises a gel composition comprising an alkaloid compound. In particularly preferred embodiments, the aerosol-forming substrate comprises a gel composition comprising nicotine.

[0195] Preferably, the gel composition comprises an alkaloid compound; an aerosol-forming agent; 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.

[0196] Advantageously, the stable gel composition comprising nicotine provides a predictable composition form during storage or during shipment from the manufacturer to the consumer. The stable gel composition comprising nicotine substantially maintains its shape. The stable gel composition comprising nicotine does not substantially release a liquid phase during storage or during shipment from the manufacturer to the consumer. The stable gel composition comprising nicotine can provide a simple consumable design. The consumable does not need to be designed to contain a liquid, thus allowing for a wider range of materials and container configurations.

[0197] The gel compositions described herein can be combined with an aerosol-generating device to deliver nicotine aerosol to the lungs at an inhalation rate or airflow rate within the range of conventional smoking. The aerosol-generating device can continuously heat the gel composition. The consumer can take multiple inhalations, or "puffs," with each "puff" delivering a certain amount of nicotine aerosol. When heated, preferably continuously, the gel composition is capable of delivering a high-nicotine / low-total-particulate-matter (TPM) aerosol to the consumer.

[0198] 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 may not substantially release (sweat) or absorb water when exposed to standard temperature and pressure while the relative humidity changes from about 10% to about 60%. For example, a stable gel may substantially maintain its shape and mass when exposed to standard temperature and pressure while the relative humidity changes from about 10% to about 60%.

[0199] The gel composition may include an alkaloid compound.The gel composition may include one or more alkaloids.

[0200] The term "alkaloid compound" refers to any 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. One or more nitrogen atoms in the alkaloid compound molecule can act as a base in an acid-base reaction. In most alkaloid compounds, one or more of the nitrogen atoms is part of a ring system, such as a heterocycle. In nature, alkaloid compounds are primarily found in plants and are particularly common 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 alkaloid compounds of natural origin and synthetically produced alkaloid compounds.

[0201] The gel composition may preferably include an alkaloid compound selected from the group consisting of nicotine, anacitabine, and combinations thereof.

[0202] Preferably, the gel composition comprises nicotine.

[0203] The term "nicotine" refers to nicotine and nicotine derivatives, such as freebase nicotine, nicotine salts, and the like.

[0204] The gel composition preferably includes about 0.5% to about 10% by weight of the alkaloid compound. The gel composition may 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 may preferably include about 1.5% to about 2.5% by weight of the alkaloid compound. The gel composition may preferably include about 2% by weight of the alkaloid compound. The alkaloid compound component of the gel formulation may be the most volatile component of the gel formulation. In some aspects, water may be the most volatile component of the gel formulation, and the alkaloid compound component of the gel formulation may be the second most volatile component of the gel formulation. In some aspects, water may be the most volatile component of the gel formulation, and the alkaloid compound component of the gel formulation may be the second most volatile component of the gel formulation.

[0205] 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 nicotine, or about 0.5% to about 5% by weight of nicotine. Preferably, the gel composition includes about 1% to about 3% by weight of nicotine, or about 1.5% to about 2.5% by weight of nicotine, or about 2% by weight of nicotine. The nicotine component of the gel formulation can be the most volatile component of the gel formulation. In some aspects, water can be the most volatile component of the gel formulation, and the nicotine component of the gel formulation can be the second most volatile component of the gel formulation.

[0206] 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, polyols such as triethylene glycol, 1,3-butylene glycol, and glycerol; esters of polyols such as glycerol mono-, di-, or triacetate; and aliphatic esters of mono-, di-, or polycarboxylic acids such as dimethyl dodecanedioate and dimethyl tetradecanedioate. The polyol or mixture thereof may be one or more of triethylene glycol, 1,3-butylene glycol, glycerol (glycerol or propane-1,2,3-triol), or polyethylene glycol. The aerosol former is preferably glycerol.

[0207] The gel composition may include a majority of an aerosol former. The gel composition may include a mixture of water and an aerosol former, wherein the aerosol former forms a majority of the gel composition (by weight). The aerosol former may form at least about 50% by weight of the gel composition. The aerosol former may 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 may form from about 70% to about 80% by weight of the gel composition. The aerosol former may form from about 70% to about 75% by weight of the gel composition.

[0208] The gel composition may include a majority of glycerin. The gel composition may include a mixture of water and glycerin, wherein the glycerin forms a majority of the gel composition (by weight). Glycerin may form at least about 50% by weight of the gel composition. Glycerin may 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. Glycerin may form from about 70% to about 80% by weight of the gel composition. Glycerin may form from about 70% to about 75% by weight of the gel composition.

[0209] The gel composition preferably includes at least one gelling agent. Preferably, the gel composition includes a total amount of gelling agent in a range of about 0.4% to about 10% by weight. More preferably, the composition includes a gelling agent in a range of about 0.5% to about 8% by weight. More preferably, the composition includes a gelling agent in a range of about 1% to about 6% by weight. More preferably, the composition includes a gelling agent in a range of about 2% to about 4% by weight. More preferably, the composition includes a gelling agent in a range of about 2% to about 3% by weight.

[0210] The term "gelling agent" refers to a compound that, when added to a mixture of 50% by weight water / 50% by weight glycerol in an amount of about 0.3% by weight, homogeneously forms a solid medium or support matrix that results in a gel. Gelling agents include, but are not limited to, hydrogen-bonding crosslinking gelling agents and ionic crosslinking gelling agents.

[0211] The gelling agent may comprise one or more biopolymers. The biopolymer may be formed from a polysaccharide.

[0212] Biopolymers include, for example, gellan gum (natural, low acyl gellan gum, high acyl gellan gum, preferably low acyl gellan gum), xanthan gum, alginates (alginic acid), agar, guar gum, and the like. The composition may preferably include xanthan gum. The composition may include two biopolymers. The composition may include three biopolymers. The composition may include substantially equal weights of the two biopolymers. The composition may include substantially equal weights of the three biopolymers.

[0213] Preferably, the gel composition includes at least about 0.2% by weight of a hydrogen-bonding cross-linking gelling agent. The gel composition preferably includes at least about 0.2% by weight of an ionic cross-linking gelling agent. Most preferably, the gel composition includes at least about 0.2% by weight of a hydrogen-bonding cross-linking gelling agent and at least about 0.2% by weight of an ionic cross-linking gelling agent. The gel composition may include about 0.5% to about 3% by weight of a hydrogen-bonding cross-linking gelling agent and about 0.5% to about 3% by weight of an ionic cross-linking gelling agent, or about 1% to about 2% by weight of a hydrogen-bonding cross-linking gelling agent and about 1% to about 2% by weight of an ionic cross-linking gelling agent. The hydrogen-bonding cross-linking gelling agent and the ionic cross-linking gelling agent may be present in the gel composition in substantially equal amounts by weight.

[0214] The term "hydrogen-bonding crosslinking gelling agent" refers to a gelling agent that forms non-covalent or physical crosslinks via hydrogen bonding. Hydrogen bonding is a type of electrostatic dipole-dipole attraction between molecules, rather than a covalent bond to a hydrogen atom. It results from the attractive force between a hydrogen atom covalently bonded to an extremely electronegative atom (such as a nitrogen, oxygen, or fluorine atom) and another extremely electronegative atom.

[0215] The hydrogen bond cross-linking gelling agent may include one or more of galactomannan, gelatin, agarose, konjac gum or agar. The hydrogen bond cross-linking gelling agent may preferably include agar.

[0216] The gel composition preferably includes a hydrogen-bonding cross-linking gelling agent in a range of about 0.3% to about 5% by weight. Preferably, the composition includes a hydrogen-bonding cross-linking gelling agent in a range of about 0.5% to about 3% by weight. Preferably, the composition includes a hydrogen-bonding cross-linking gelling agent in a range of about 1% to about 2% by weight.

[0217] The gel composition may include galactomannan in the range of about 0.2% to about 5% by weight. Preferably, the galactomannan may be in the range of about 0.5% to about 3% by weight. Preferably, the galactomannan may be in the range of about 0.5% to about 2% by weight. Preferably, the galactomannan may be in the range of about 1% to about 2% by weight.

[0218] The gel composition may include gelatin in a range of about 0.2% to about 5% by weight. Preferably, the gelatin may be in a range of about 0.5% to about 3% by weight. Preferably, the gelatin may be in a range of about 0.5% to about 2% by weight. Preferably, the gelatin may be in a range of about 1% to about 2% by weight.

[0219] The gel composition may include agarose in a range of about 0.2% to about 5% by weight. Preferably, the agarose may be in a range of about 0.5% to about 3% by weight. Preferably, the agarose may be in a range of about 0.5% to about 2% by weight. Preferably, the agarose may be in a range of about 1% to about 2% by weight.

[0220] The gel composition may include konjac gum in a range of about 0.2% to about 5% by weight. Preferably, konjac gum may be in a range of about 0.5% to about 3% by weight. Preferably, konjac gum may be in a range of about 0.5% to about 2% by weight. Preferably, konjac gum may be in a range of about 1% to about 2% by weight.

[0221] The gel composition may include agar in a range of about 0.2% to about 5% by weight. Preferably, the agar may be in a range of about 0.5% to about 3% by weight. Preferably, the agar may be in a range of about 0.5% to about 2% by weight. Preferably, the agar may be in a range of about 1% to about 2% by weight.

[0222] The term "ionic crosslinking gelling agent" refers to a gelling agent that forms non-covalent or physical crosslinks via ionic bonds. Ionic crosslinking involves the association of polymer chains through non-covalent interactions. A crosslinked network forms when oppositely charged multivalent molecules are electrostatically attracted to each other, forming a crosslinked polymer network.

[0223] The ionically cross-linked gelling agent may include low acyl gellan gum, pectin, kappa-carrageenan, iota-carrageenan or alginate. The ionically cross-linked gelling agent may preferably include low acyl gellan gum.

[0224] The gel composition may include an ionically cross-linked gelling agent in the range of about 0.3% to about 5% by weight. Preferably, the composition includes an ionically cross-linked gelling agent in the range of about 0.5% to about 3% by weight. Preferably, the composition includes an ionically cross-linked gelling agent in the range of about 1% to about 2% by weight.

[0225] The gel composition may include low acyl gellan gum in a range of about 0.2% to about 5% by weight. Preferably, the low acyl gellan gum may be in a range of about 0.5% to about 3% by weight. Preferably, the low acyl gellan gum may be in a range of about 0.5% to about 2% by weight. Preferably, the low acyl gellan gum may be in a range of about 1% to about 2% by weight.

[0226] The gel composition may include pectin in a range of about 0.2% to about 5% by weight. Preferably, the pectin may be in a range of about 0.5% to about 3% by weight. Preferably, the pectin may be in a range of about 0.5% to about 2% by weight. Preferably, the pectin may be in a range of about 1% to about 2% by weight.

[0227] The gel composition may include kappa carrageenan in a range of about 0.2% to about 5% by weight. Preferably, kappa carrageenan may be in a range of about 0.5% to about 3% by weight. Preferably, kappa carrageenan may be in a range of about 0.5% to about 2% by weight. Preferably, kappa carrageenan may be in a range of about 1% to about 2% by weight.

[0228] The gel composition can include iota carrageenan in a range of about 0.2% to about 5% by weight. Preferably, iota carrageenan can be in a range of about 0.5% to about 3% by weight. Preferably, iota carrageenan can be in a range of about 0.5% to about 2% by weight. Preferably, iota carrageenan can be in a range of about 1% to about 2% by weight.

[0229] The gel composition may include alginate in a range of about 0.2% to about 5% by weight. Preferably, the alginate may be in a range of about 0.5% to about 3% by weight. Preferably, the alginate may be in a range of about 0.5% to about 2% by weight. Preferably, the alginate may be in a range of about 1% to about 2% by weight.

[0230] The gel composition may include the hydrogen-bonding cross-linking gelling agent and the ionic cross-linking gelling agent in a ratio of about 3:1 to about 1:3. Preferably, the gel composition may include the hydrogen-bonding cross-linking gelling agent and the ionic cross-linking gelling agent in a ratio of about 2:1 to about 1:2. Preferably, the gel composition may include the hydrogen-bonding cross-linking gelling agent and the ionic cross-linking gelling agent in a ratio of about 1:1.

[0231] The gel composition may also include a viscosity increasing agent. The viscosity increasing agent in combination with the hydrogen bonding cross-linking gelling agent and the ion bonding cross-linking gelling agent appears to unexpectedly support the solid medium and maintain the gel composition even when the gel composition includes high levels of glycerol.

[0232] The term "viscosity increasing agent" refers to a compound that, when homogenously added in an amount of 0.3% by weight to a mixture of 50% by weight water / 50% by weight glycerol at 25 degrees Celsius, increases viscosity without causing gel formation, the mixture remaining or remaining fluid. Preferably, the viscosity increasing agent refers to a compound that, when homogenously added in an amount of 0.3% by weight to a mixture of 50% by weight water / 50% by weight glycerol at 25 degrees Celsius, increases viscosity to at least 50 cPs, preferably at least 200 cPs, preferably at least 500 cPs, preferably at least 1000 cPs at a shear rate of 0.1 s-1, without causing gel formation, the mixture remaining or remaining fluid. Preferably, the viscosity increasing agent refers to a compound that, when homogeneously added in an amount of 0.3 wt % to a mixture of 50 wt % water / 50 wt % glycerol at 25 degrees Celsius, increases the viscosity by at least 2 times, or at least 5 times, or at least 10 times, or at least 100 times at a shear rate of 0.1 s-1 compared to before addition, without causing gel formation, and the mixture remains or remains fluid.

[0233] The viscosity values stated herein can be measured using a Brookfield RVT viscometer at 25 degrees Celsius with a rotating disc RV#2 spindle at 6 revolutions per minute (rpm).

[0234] The gel composition preferably includes a viscosity increasing agent in a range of about 0.2% to about 5% by weight. Preferably, the composition includes a viscosity increasing agent in a range of about 0.5% to about 3% by weight. Preferably, the composition includes a viscosity increasing agent in a range of about 0.5% to about 2% by weight. Preferably, the composition includes a viscosity increasing agent in a range of about 1% to about 2% by weight.

[0235] The viscosity increasing agent may 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 may preferably include xanthan gum.

[0236] The gel composition may include xanthan gum in a range of about 0.2% to about 5% by weight. Preferably, the xanthan gum may be in a range of about 0.5% to about 3% by weight. Preferably, the xanthan gum may be in a range of about 0.5% to about 2% by weight. Preferably, the xanthan gum may be in a range of about 1% to about 2% by weight.

[0237] The gel composition may include carboxymethyl cellulose in a range of about 0.2% to about 5% by weight. Preferably, the carboxymethyl cellulose may be in a range of about 0.5% to about 3% by weight. Preferably, the carboxymethyl cellulose may be in a range of about 0.5% to about 2% by weight. Preferably, the carboxymethyl cellulose may be in a range of about 1% to about 2% by weight.

[0238] The gel composition may include microcrystalline cellulose in a range of about 0.2% to about 5% by weight. Preferably, the microcrystalline cellulose may be in a range of about 0.5% to about 3% by weight. Preferably, the microcrystalline cellulose may be in a range of about 0.5% to about 2% by weight. Preferably, the microcrystalline cellulose may be in a range of about 1% to about 2% by weight.

[0239] The gel composition may include methylcellulose in a range of about 0.2% to about 5% by weight. Preferably, the methylcellulose may be in a range of about 0.5% to about 3% by weight. Preferably, the methylcellulose may be in a range of about 0.5% to about 2% by weight. Preferably, the methylcellulose may be in a range of about 1% to about 2% by weight.

[0240] The gel composition may include gum arabic in a range of about 0.2% to about 5% by weight. Preferably, the gum arabic may be in a range of about 0.5% to about 3% by weight. Preferably, the gum arabic may be in a range of about 0.5% to about 2% by weight. Preferably, the gum arabic may be in a range of about 1% to about 2% by weight.

[0241] The gel composition may include guar gum in a range of about 0.2% to about 5% by weight. Preferably, the guar gum may be in a range of about 0.5% to about 3% by weight. Preferably, the guar gum may be in a range of about 0.5% to about 2% by weight. Preferably, the guar gum may be in a range of about 1% to about 2% by weight.

[0242] The gel composition may include lambda carrageenan in a range of about 0.2% to about 5% by weight. Preferably, lambda carrageenan may be in a range of about 0.5% to about 3% by weight. Preferably, lambda carrageenan may be in a range of about 0.5% to about 2% by weight. Preferably, lambda carrageenan may be in a range of about 1% to about 2% by weight.

[0243] The gel composition may include starch in a range of about 0.2% to about 5% by weight. Preferably, the starch may be in a range of about 0.5% to about 3% by weight. Preferably, the starch may be in a range of about 0.5% to about 2% by weight. Preferably, the starch may be in a range of about 1% to about 2% by weight.

[0244] The gel composition may also include divalent cations. Preferably, the divalent cations include calcium ions, such as calcium lactate in solution. For example, divalent cations (such as calcium ions) can aid in the formation of a gel in a composition that includes a gelling agent, such as an ionically crosslinked gelling agent. Ionic effects can aid gel formation. The divalent cations can be present in the gel composition in a range of about 0.1% to about 1% by weight, or about 0.5% by weight.

[0245] The gel composition may also include an acid. The acid may include a carboxylic acid. The carboxylic acid may include a ketone group. Preferably, the carboxylic acid may include a ketone group having less than about 10 carbon atoms, 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 may aid gel formation. During storage, the carboxylic acid may reduce variations in the concentration of alkaloid compounds in the gel composition. During storage, the carboxylic acid may reduce variations in the concentration of nicotine in the gel composition.

[0246] The gel composition may include a carboxylic acid in a range of about 0.1% to about 5% by weight. Preferably, the carboxylic acid may be in a range of about 0.5% to about 3% by weight. Preferably, the carboxylic acid may be in a range of about 0.5% to about 2% by weight. Preferably, the carboxylic acid may be in a range of about 1% to about 2% by weight.

[0247] The gel composition may include lactic acid in a range of about 0.1 wt % to about 5 wt %. Preferably, the lactic acid may be in a range of about 0.5 wt % to about 3 wt %. Preferably, the lactic acid may be in a range of about 0.5 wt % to about 2 wt %. Preferably, the lactic acid may be in a range of about 1 wt % to about 2 wt %.

[0248] The gel composition may include levulinic acid in a range of about 0.1% to about 5% by weight. Preferably, levulinic acid may be in a range of about 0.5% to about 3% by weight. Preferably, levulinic acid may be in a range of about 0.5% to about 2% by weight. Preferably, levulinic acid may be in a range of about 1% to about 2% by weight.

[0249] 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% by weight, or at least about 2% by weight, or at least about 5% by weight water. Preferably, the gel composition includes at least about 10% by weight or at least about 15% by weight water.

[0250] Preferably, the gel composition comprises between about 8% and 32% water by weight. Preferably, the gel composition comprises between about 15% and about 25% water by weight. Preferably, the gel composition comprises between about 18% and about 22% water by weight. Preferably, the gel composition comprises about 20% water by weight.

[0251] Preferably, the aerosol-forming substrate comprises between about 150 mg and about 350 mg of the gel composition.

[0252] Preferably, in embodiments comprising a gel composition, the aerosol-forming substrate comprises a porous medium loaded with the gel composition. An advantage of a porous medium loaded with the gel composition is that the gel composition is retained within the porous medium, and this may facilitate the manufacture, storage, or transport of the gel composition. This may help maintain the desired shape of the gel composition, particularly during manufacture, transport, or use.

[0253] 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.

[0254] The porous medium can be any suitable porous material capable of containing or retaining the gel composition. Ideally, the porous medium allows the gel composition to move therein. In certain embodiments, the porous medium comprises a natural material, a synthetic or semi-synthetic material, or a combination thereof. In certain embodiments, the porous medium comprises a sheet material, a foam, or fibers, such as loose fibers; or a combination thereof. In certain embodiments, the porous medium comprises a woven, non-woven, 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.

[0255] The porous medium can be rolled or chopped. In a preferred embodiment, the porous medium is rolled. In an alternative embodiment, the porous medium comprises chopped porous medium. The rolling or chopped process can be before or after loading the gel composition.

[0256] Curling the sheet material has the benefit of improving the structure to allow passage through the structure. The passage through the curled sheet material helps to load the gel, retain the gel, and also helps to pass the fluid through the curled sheet material. Therefore, using a curled sheet material as a porous medium has advantages.

[0257] Mincing enables a high surface area to volume ratio of the medium to readily absorb the gel.

[0258] In some embodiments, the sheet material is a composite material. Preferably, the sheet material is porous. The sheet material can facilitate the manufacture of tubular elements comprising gels. The sheet material can facilitate the introduction of active agents into tubular elements comprising gels. The sheet material can help stabilize the structure of tubular elements comprising gels. The sheet material can aid in the transport or storage of gels. The use of the sheet material can enable or facilitate the addition of structure to porous media, for example, by curling the sheet material.

[0259] The porous medium may be a thread. The thread may comprise, for example, cotton, paper, or acetate tow. The thread may also be loaded with gel, as with any other porous medium. The advantage of using a thread as the porous medium is that it facilitates ease of manufacture.

[0260] The thread may be loaded with gel by any known means. The thread may simply be coated with gel, or the thread may be impregnated with gel. In manufacture, the thread may be impregnated with gel and stored ready for inclusion in the assembly of the tubular element.

[0261] Preferably, in embodiments where the first element comprises a gel composition, as described above, the tubular element has a length of less than 10 mm. The use of such a relatively short tubular element in combination with the gel composition can optimize aerosol delivery to the consumer.

[0262] Embodiments of the present invention in which the aerosol-forming substrate comprises a gel composition as described above preferably comprise an upstream element upstream of the first element comprising the aerosol-forming substrate. In this case, the upstream element advantageously prevents physical contact with the gel composition. The upstream element may 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-forming substrate during use.

[0263] According to a third aspect of the present invention, there is provided a method of forming a tubular element for use in an aerosol-generating article as described herein. The method comprises providing a tubular element precursor, the tubular element precursor comprising a tubular body, and a first end portion adjacent to and integrally formed with a first end of the tubular body, the tubular body defining a lumen extending along a longitudinal axis from the first end of the tubular body to the second end of the tubular body. The method further comprises cutting the first end portion at an angle to the longitudinal axis, thereby providing the tubular element precursor with an angled first end portion. The method further comprises applying a folding force to the tubular element precursor to bend or fold the angled first end portion about a fold point corresponding to the first end of the tubular body, the folding force being applied such that at least a portion of the angled first end portion of the tubular element extends into the lumen of the tubular body. The method may further comprise releasing the folding force such that the angled first end portion of the tubular element partially recovers along its folded path and reaches a position in which the angled 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 defines an opening for fluidly connecting the lumen and an exterior of the tubular element.

[0264] Preferably, the step of cutting the first end portion at an angle to the longitudinal axis comprises cutting the first end portion such that an angle between 10 and 80 degrees is formed between the cut line and the longitudinal axis, for example, between 20 and 80 degrees, between 30 and 80 degrees, or between 30 and 70 degrees.

[0265] According to a fourth aspect of the present invention, there is provided an electrically heated aerosol-generating system comprising an aerosol-generating article as described herein, and an aerosol-generating device comprising electrical components for heating the aerosol-forming substrate.

[0266] The aerosol generating device may include a power source. The power source may be configured to supply power to the electrical components. The power source may be any suitable power source, such as a DC voltage source, such as a battery. In one embodiment, the power source is a lithium-ion battery. Alternatively, the power source may be a nickel-metal hydride battery, a nickel-cadmium battery, or a lithium-based battery such as a lithium-cobalt, lithium-iron-phosphate, lithium titanate, or lithium-polymer battery.

[0267] The electrical element may be a heating element. The heating element may be arranged within or around the heating chamber for heating the aerosol-generating article insertable into the heating chamber. The heating chamber may be a cavity.

[0268] The aerosol-generating device may comprise an internal heating element, such as a pin or blade, at least partially inserted into the aerosol-forming substrate for use.The internal heating element may be configured to be inserted into a radially central position of the aerosol-forming substrate.

[0269] The aerosol generating device may include an external heating element positioned around the periphery of the heating chamber. The external heating element may take any suitable form. For example, the external heating element may take the form of one or more flexible heating foils on a dielectric substrate (e.g., polyimide). The flexible heating foils may be shaped to conform to the periphery of the heating chamber. Alternatively, the external heating element may take the form of a metal grid, a flexible printed circuit board, a molded interconnect device (MID), a ceramic heating element, a flexible carbon fiber heating element, or may be formed on a suitable molded substrate using a coating technique, such as plasma vapor deposition.

[0270] It will be appreciated that any feature described with reference to one aspect of the invention or disclosure is equally applicable to any other aspect of the invention or disclosure.

[0271] The present invention is defined in the claims. However, a non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples may be combined with any one or more features of another example, embodiment or aspect described herein.

[0272] Ex1. An aerosol-generating article comprising:

[0273] a first element comprising an aerosol-forming substrate; and

[0274] a tubular element positioned downstream of the first element, the tubular element having a radial central axis and including an end wall formed by a folded end portion of the tubular element;

[0275] Wherein the end wall defines an opening having a perimeter for fluidly connecting an interior of the tubular element and an exterior of the tubular element, and wherein a radial center axis of the tubular element is positioned outside of the perimeter of the opening.

[0276] Ex2. An aerosol-generating article comprising:

[0277] a first element comprising an aerosol-forming substrate; and

[0278] a tubular element positioned downstream of the first element, the tubular element having a radial central axis and including an end wall formed by a folded end portion of the tubular element;

[0279] wherein the end wall defines an opening having a geometric center for fluidly connecting an interior of the tubular element and an exterior of the tubular element, and wherein the geometric center of the opening is radially spaced from a radial center axis of the tubular element by at least 10% of a diameter of the end wall.

[0280] Ex3. An aerosol-generating article according to Ex1 or Ex2, wherein the end wall is an upstream end wall.

[0281] Ex4. An aerosol-generating article according to any one of Ex1 to Ex3, wherein the end wall is a downstream end wall.

[0282] Ex5. An aerosol-generating article according to any one of Ex1 to Ex4, wherein the tubular element is adjacent to the first element.

[0283] Ex6. An aerosol-generating article according to Ex5, wherein the first element and the tubular element are in contact with each other.

[0284] Ex7. An aerosol-generating article according to Ex5 or Ex6, wherein the tubular element restricts downstream movement of the aerosol-forming substrate.

[0285] Ex8. An aerosol-generating article according to any one of Ex1 to Ex7, wherein the opening defined by the end wall is the only opening in the end wall.

[0286] Ex9. An aerosol-generating article according to any one of Ex1 to Ex8, wherein the end wall defines a single opening, and the opening is the single opening.

[0287] Ex10. An aerosol-generating article according to any one of Ex1 to Ex9, wherein the periphery of the opening is radially spaced from the radial center axis of the tubular element by at least 5% of the diameter of the end wall, or wherein the geometric center of the opening is radially spaced from the radial center axis of the tubular element by at least 5% of the diameter of the end wall.

[0288] Ex11. An aerosol-generating article according to any one of Ex1 to Ex10, wherein the opening coincides with the periphery of the end wall.

[0289] Ex 12. An aerosol-generating article according to any one of Ex 1 to Ex 11, wherein the opening has an equivalent diameter greater than about 2 mm.

[0290] Ex 13. An aerosol-generating article according to any one of Ex 1 to Ex 12, wherein the opening has an equivalent diameter that is equal to or greater than 10% of the diameter of the end wall.

[0291] Ex 14. An aerosol-generating article according to any one of Ex 1 to Ex 13, wherein the end wall comprises a central region coaxial with the radial central axis of the tubular element, and the end wall comprises a peripheral region defining the central region.

[0292] Ex15. An aerosol-generating article according to Ex14, wherein the central region is circular in shape.

[0293] Ex 16. An aerosol-generating article according to Ex 14 or Ex 15, wherein the central region is air-impermeable.

[0294] Ex17. An aerosol-generating article according to any one of Ex14 to Ex16, wherein the opening is defined in the peripheral region.

[0295] Ex18. An aerosol-generating article according to any one of Ex14 to Ex17, wherein the central region is equal to or greater than 30% of the end wall diameter.

[0296] Ex19. An aerosol-generating article according to any one of Ex1 to Ex18, further comprising a ventilation zone at a position along the tubular element.

[0297] Ex20. An aerosol-generating article according to any one of Ex1 to Ex19, wherein the tubular element comprises a first end and a second end positioned opposite to the first end, and wherein the end wall is a first end wall formed by a first folded end portion, and the tubular element comprises a second end wall formed by a second folded end portion, and wherein the second end wall defines an opening for fluidly connecting the interior of the tubular element and the exterior of the tubular element.

[0298] Ex21. An aerosol-generating article according to any one of Ex1 to Ex20, wherein the first element comprises a susceptor element positioned at a radially central position within the aerosol-forming substrate and extending along the longitudinal axis of the aerosol-forming substrate.

[0299] Ex22. An aerosol-generating article according to any one of Ex1 to Ex21, wherein the tubular element defines a lumen extending from an upstream end of the tubular element to a downstream end of the tubular element.

[0300] Ex23. An aerosol-generating article according to Ex22, wherein the cavity is substantially empty.

[0301] Ex24. An aerosol-generating article according to Ex1 to Ex23, wherein the tubular element is formed from cardboard.

[0302] Ex25. An electrically heated aerosol generating system comprising an aerosol-generating article according to any one of Ex1 to Ex25, and an aerosol generating device comprising a heating element for heating the aerosol-forming substrate.

[0303] Ex26. A method of forming a tubular element for an aerosol-generating article according to any one of Ex1 to Ex24, the method comprising:

[0304] providing a tubular element precursor comprising a tubular body and a first end portion adjacent to and integrally formed with a first end of the tubular body, the tubular body defining a lumen extending along a longitudinal axis from the first end of the tubular body to a second end of the tubular body;

[0305] cutting the first end portion at an angle to the longitudinal axis, thereby providing the tubular element precursor with an angled first end portion;

[0306] A folding force is applied to the tubular element precursor to bend or fold the angled 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 angled first end portion of the tubular element extends into the lumen of the tubular body. BRIEF DESCRIPTION OF THE DRAWINGS

[0307] Several examples will now be further described with reference to the accompanying drawings, in which:

[0308] Figure 1 shows a schematic side cross-sectional view of an aerosol-generating article according to a first embodiment of the present invention;

[0309] Figure 2 Shown Figure 1 a perspective view of a tubular element of an aerosol-generating article;

[0310] Figures 3A to 3E shows a schematic side cross-sectional view depicting a stage in forming the tubular element of FIG. 3 ;

[0311] Figure 4 shows a schematic side cross-sectional view of an aerosol-generating article according to a second embodiment of the invention;

[0312] Figure 5 shows a schematic side cross-sectional view of an aerosol-generating article according to a third embodiment of the invention;

[0313] Figure 6 shows a schematic side cross-sectional view of an aerosol-generating article according to a fourth embodiment of the invention;

[0314] Figure 7 A schematic side cross-sectional view of an aerosol-generating article according to a fifth embodiment of the invention is shown. DETAILED DESCRIPTION

[0315] Figure 1 An aerosol-generating article 1 according to a first embodiment of the present invention is shown. The aerosol-generating article 1 comprises a first element 11 comprising an aerosol-forming substrate 12, and a downstream section 14 at a position downstream of the first element 11. Furthermore, the aerosol-generating article 1 comprises an upstream section 16 at a position upstream of the first element 11. Thus, the aerosol-generating article 1 extends from an upstream end or distal end 18 to a downstream end or mouth end 20.

[0316] The aerosol-generating article has an overall length of approximately 45 mm.

[0317] The downstream section 14 comprises a tubular element 100 positioned immediately downstream of the first element 11, the tubular element 100 being longitudinally aligned with the first element 11. Figure 1 In the embodiment of FIG. 5 , 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-forming substrate 12 .

[0318] In addition, the downstream section 14 includes a mouthpiece element 42 at a position downstream of the tubular element 100. In more detail, the mouthpiece element 42 is located immediately downstream of the tubular element 100. Figure 1 As shown in FIG, the upstream end of the mouthpiece member 42 abuts the downstream end of the tubular member 100.

[0319] 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 mm and an outer diameter of about 7.25 mm. The RTD of the mouthpiece element 42 is about 12 mm H2O.

[0320] The aerosol-generating article 1 includes a ventilation zone 60 disposed at a position along the tubular element 100. In more detail, the ventilation zone is disposed approximately 4 mm from the downstream end of the tubular element 100. The ventilation level of the aerosol-generating article 10 is approximately 40%. The ventilation zone provides various advantages as discussed above, but it should be recognized that the following embodiments may alternatively not include a ventilation zone.

[0321] The first element 11 is in the form of a strip comprising an aerosol-forming substrate 12 of one of the types described above. The aerosol-forming substrate 12 may substantially define the structure and dimensions of the strip 11. The strip 11 may also comprise a wrapper (not shown) that confines the aerosol-forming substrate 12. The strip 11 comprising the aerosol-forming substrate has an outer diameter of approximately 7.25 mm and a length of approximately 12 mm.

[0322] The first element 11 further comprises an elongate susceptor element 44 within the aerosol-forming substrate 12. In more detail, the susceptor element 44 is arranged substantially longitudinally within the aerosol-forming substrate 12 so as to be substantially parallel to the longitudinal direction of the strip 11. Figure 1 As shown in the Figures, the susceptor element 44 is positioned at a radially central position within the strip and effectively extends along the longitudinal axis of the strip 11.

[0323] The susceptor element 44 extends from the upstream end to the downstream end of the aerosol-forming substrate 12. In practice, the susceptor element 44 has substantially the same length as the first element 11 comprising the aerosol-forming substrate 12.

[0324] exist Figure 1 In the embodiment of FIG. 4 , the susceptor element 44 is provided in the form of a strip and has a length of about 12 mm, a thickness of about 60 microns, and a width of about 4 mm.

[0325] The upstream section 16 comprises an upstream element 46 positioned immediately upstream of the first element 11, the upstream element 46 being longitudinally aligned with the first element 11. Figure 1In the embodiment of FIG. 4 , 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-forming substrate 12. This advantageously prevents displacement of the susceptor element 44. Furthermore, this ensures that the consumer does not accidentally come into contact with the heated susceptor element 44 after use.

[0326] The upstream element 46 is provided in the form of a cylindrical filter segment of cellulose acetate defined by a rigid wrapper. The upstream element 46 has a length of approximately 5 mm. The RTD of the upstream element 46 is approximately 30 mm H2O.

[0327] The tubular element 100 defines a cavity 106 extending from a first or upstream end 101 of the tubular element 100 to a second or downstream end 102 of the tubular element 100. The tubular element 100 includes an end wall 104 formed by a folded end portion of the tubular element 100. The end wall 104 defines an opening 110 for fluidly connecting the cavity 106 to the exterior of the tubular element 100. In particular, Figure 1 The embodiment is configured such that an aerosol can flow from the first element 11 through the opening 110 into the cavity 106 .

[0328] The cavity 106 is substantially empty, and thus substantially unrestricted airflow is achieved along the cavity 106. Thus, the RTD of the tubular element 100 can be localized at a specific longitudinal location of the tubular element 100 (i.e., at the end wall 104) and can be controlled by the selected configuration of the end wall 104 and the opening 110. Figure 1 In the embodiment of the present invention, the RTD of the tubular element 100 (which is substantially the RTD of the end wall 104) is substantially 40 mm H2O. Figure 1 In the embodiment of the present invention, the tubular element 100 has a length of about 16 mm, an outer diameter of about 7.25 mm, and an inner diameter of about 6.5 mm. Therefore, the thickness of the peripheral wall (or tubular wall) of the tubular element 100 is about 0.75 mm.

[0329] like Figure 1 As shown in and also in Figure 2 , the end wall 104 extends substantially transversely to the longitudinal direction of the aerosol-generating article 1 and the longitudinal direction of the tubular element 100. The opening 110 has an equivalent diameter of approximately 3 mm. The radial central axis of the tubular element is positioned outside the periphery 111 of the opening 110. Therefore, the radial central axis does not extend through the opening.

[0330] The combination of the end wall 104 and the opening 110 provides an effective barrier arrangement that can restrict the movement of the aerosol-forming substrate 12, while also enabling one or both of air and aerosol to flow from the first element 11 and through the opening 110 into the cavity 106. The opening 110 is radially spaced from the radial centre axis of the tubular element, which may be advantageous because it allows air and aerosol flowing through the opening 110 to come into closer contact with the peripheral wall of the tubular element 100.

[0331] like Figure 1 As shown in , the aerosol-generating article 1 comprises a plurality of elements assembled in the form of a strip. The plurality of elements comprises an upstream element 46, a first element 11, a tubular element 100 and a mouthpiece element 42. The plurality of elements is defined by an outer wrapper 109. The outer wrapper 109 is made of paper.

[0332] Figures 3A to 3E A tubular element for use in an aerosol-generating article according to the present invention is shown through different stages of its formation. Thus, these figures illustrate the formation of a tubular element such as Figure 1 Method of tubular element 100).

[0333] As Figure 3A As shown, the method begins by providing a tubular element precursor 300 comprising a tubular body 303, and a first end portion 305 adjacent to and integrally formed with a first end of the tubular body, the tubular body defining a lumen 306 extending along a longitudinal axis from the first end of the tubular body to the second end of the tubular body. The method then includes cutting the first end portion 305 at an angle to the longitudinal axis, thereby providing the tubular element precursor 303 with an angled first end portion. Figure 3A , line AA depicts the cutting line.

[0334] To form the end wall 104, a folding force is applied to the tubular element precursor 300 to bend the angled first end portion about the fold point 307. The folding force causes the angled first end portion to bend inwardly relative to the tubular body 303 (e.g., by Figure 3B 、 3C and the dotted curved arrow in 3D) and deflects toward the cavity 306. The folding force continues to be applied until the angled first end portion has folded to an angle greater than 90 degrees (as measured relative to the wall of the tubular body 303). This position is Figure 3D Depicted in. Figure 3D It can be seen that in this position, at least a portion of the angled first end portion of the tubular element precursor extends into the lumen 306. In other words, at least a portion of the angled first end portion of the tubular element has a longitudinal position that is between the longitudinal position of the first end of the tubular body 303 and the longitudinal position of the second end of the tubular body 303.

[0335] Once the angled first end portion reaches Figure 3D At this point, the inherent elastic properties of the paper material (such as paper, paperboard or cardboard) of the tubular element precursor 300 will cause the angled first end portion to partially recover along its folded path, so that the angled first end portion reaches a position where it extends substantially transversely to the longitudinal direction of the tubular body 303. This position is determined by Figure 3E Shown.

[0336] exist Figures 3A to 3E In the arrangement of FIG, only one end of the tubular element precursor 300 is folded; however, it will be appreciated that similar method steps may be applied to the other end of the tubular element precursor 100 in order to obtain a tubular element having two folded end portions, each folded end portion forming a respective first and second end wall of the tubular element.

[0337] Figure 4 An aerosol-generating article 2 according to a second embodiment of the present invention is shown. The aerosol-generating article 2 of the second embodiment is substantially identical to the aerosol-generating article 1 of the first embodiment, except that the aerosol-generating article 2 of the second embodiment does not include any form of upstream element 46 upstream of the first element 11. Thus, the upstream end or distal end 18 of the aerosol-generating article 2 is defined by the first element 11. Furthermore, in the second embodiment of the present invention, the first element 11 does not include a susceptor element 44 located within the aerosol-forming substrate 12. Thus, this aerosol-generating article 2 can be an article configured to receive a heater paddle of an aerosol-generating device. The heater paddle can be inserted into the aerosol-forming substrate 12 through the upstream end 18 of the aerosol-generating article 2.

[0338] The tubular element 400 of the aerosol-generating article 2 of the second embodiment is substantially identical to the tubular element 100 of the aerosol-generating article 1 of the first embodiment, except that the tubular element 400 is longer than the tubular element 100 .

[0339] Figure 5 An aerosol-generating article 3 according to a third embodiment of the invention is shown. The aerosol-generating article 3 of the third embodiment is substantially identical to the aerosol-generating article 2 of the second embodiment, and like reference numerals are used where appropriate. However, the aerosol-generating article 3 of the third embodiment does not include a mouthpiece element 42 at a position downstream of the tubular element 500. Instead, Figure 5 The tubular element 500 extends from the downstream end of the aerosol-forming substrate 12 to the mouth end 20 of the aerosol-generating article 3. Figure 5 The downstream section 14 of the aerosol-generating article 3 is formed entirely by the tubular element 500. Figure 5In the embodiment of FIG. 5 , the end wall 504 of the tubular element 500 is not disposed adjacent the downstream end of the aerosol-forming substrate 12 . Instead, the end wall 504 of the tubular element 500 is disposed at the mouth end 20 of the aerosol-generating article 3 .

[0340] Figure 6 An aerosol-generating article 4 according to a fourth embodiment of the invention is shown. The aerosol-generating article 4 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 4 of the fourth embodiment now includes a mouthpiece element in the form of a hollow tube 642 at a position downstream of the tubular element 600. Thus, Figure 6 The tubular element 600 extends all the way to the upstream end of this hollow tube 642. Therefore, Figure 6 The downstream section 14 of the aerosol-generating article 6 in is defined by the tubular element 600 and the hollow tube 642 .

[0341] Figure 7 An aerosol-generating article 5 according to a fifth embodiment of the invention is shown.The aerosol-generating article 5 of the fifth embodiment is substantially identical to the aerosol-generating article 1 of the first embodiment, and like reference numerals are used where appropriate.

[0342] However, in Figure 7 In the embodiment of the invention, the tubular element 700 is not in contact with the first element 11 comprising the aerosol-forming substrate 12. Instead, there is an empty space 750 between the downstream end of the first element 11 and the end wall 704 at the upstream end of the tubular element 700. Figure 7 In the embodiment of FIG5 , the end wall 704 of the tubular element 700 does not provide a barrier in contact with the aerosol-forming substrate 12 for restricting movement of the aerosol-forming substrate 12. However, the empty space 750 does provide an area where any loose particles or chunks from the aerosol-forming substrate 12 may collect during use of the aerosol-generating article 5. The end wall 704 may, with the aid of gravity, prevent such loose particles or chunks from moving further downstream within the aerosol-generating article 5.

[0343] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers representing amounts, quantities, percentages, etc. should be understood to be modified by the term "about" in all cases. In addition, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically listed in this article. Therefore, in this context, the number A is understood to be A±5%A. In this context, the number A can be regarded as including the numerical value within the general standard error for the measurement of the attribute modified by the number A. In certain cases used in the appended claims, the number A may deviate from the percentages listed above, provided that the amount of A deviation does not substantially affect the basic characteristics and novel features of the invention claimed. In addition, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically listed in this article.

Claims

1. An aerosol-generating article comprising: a first element comprising an aerosol-forming substrate; as well as a tubular element positioned downstream of the first element, the tubular element having a radial central axis and including an end wall formed by a folded end portion of the tubular element; Wherein the end wall defines an opening having a perimeter for fluidly connecting an interior of the tubular element and an exterior of the tubular element, and wherein a radial center axis of the tubular element is positioned outside of the perimeter of the opening.

2. An aerosol-generating article comprising: a first element comprising an aerosol-forming substrate; as well as a tubular element positioned downstream of the first element, the tubular element having a radial central axis and including an end wall formed by a folded end portion of the tubular element; wherein the end wall defines an opening having a geometric center for fluidly connecting an interior of the tubular element and an exterior of the tubular element, and wherein the geometric center of the opening is radially spaced from a radial center axis of the tubular element by at least 10% of a diameter of the end wall.

3. An aerosol-generating article according to claim 1 or 2, wherein the end wall is an upstream end wall.

4. An aerosol-generating article according to any one of claims 1 to 3, wherein the tubular element is adjacent to the first element.

5. An aerosol-generating article according to any one of claims 1 to 4, wherein the end wall defines a single opening, and the opening is the single opening.

6. An aerosol-generating article according to any one of claims 1 to 5, wherein the periphery of the opening is radially spaced from the radial centre axis of the tubular element by at least 5% of the diameter of the end wall.

7. An aerosol-generating article according to any one of claims 1 to 6, wherein the opening coincides with the periphery of the end wall.

8. An aerosol-generating article according to any one of claims 1 to 7, wherein the opening has an equivalent diameter greater than about 2 mm.

9. An aerosol-generating article according to any one of claims 1 to 8, wherein the end wall comprises a central region coaxial with the radial central axis of the tubular element, and the end wall comprises a peripheral region defining the central region, wherein the central region has a diameter equal to or greater than 10% of the diameter of the end wall, and wherein the opening is defined in the peripheral region.

10. An aerosol-generating article according to claim 9, wherein the central region is equal to or greater than 30% of the diameter of the end wall.

11. An aerosol-generating article according to claim 9 or 10, wherein the central region is air-impermeable.

12. An aerosol-generating article according to any one of claims 1 to 11, further comprising a ventilation zone at a location along the tubular element.

13. An aerosol-generating article according to any one of claims 1 to 12, wherein the first element comprises a susceptor element positioned radially centrally within the aerosol-forming substrate and extending along the longitudinal axis of the aerosol-forming substrate.

14. An aerosol-generating article according to any one of claims 1 to 13, wherein the tubular element defines a cavity extending from an upstream end to a downstream end of the tubular element, preferably the cavity is substantially hollow.

15. A method of forming a tubular element for an aerosol-generating article according to any one of claims 1 to 14, the method comprising: providing a tubular element precursor comprising a tubular body and a first end portion adjacent to and integrally formed with a first end of the tubular body, the tubular body defining a lumen extending along a longitudinal axis from the first end of the tubular body to a second end of the tubular body; cutting the first end portion at an angle to the longitudinal axis, thereby providing the tubular element precursor with an angled first end portion; as well as A folding force is applied to the tubular element precursor to bend or fold the angled 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 angled first end portion of the tubular element extends into the lumen of the tubular body.

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