Aerosol-generating article having a downstream tubular element

Abstract

An aerosol-generating article (1) is provided. The aerosol-generating article (1) includes a first element (11) having an aerosol-forming substrate (12). The aerosol-generating article (1) further includes a tubular element (100) positioned downstream of the first element (11). The tubular element (100) has an end wall (104) formed by a folded end (101) of the tubular element (100). The end wall (104) defines a plurality of openings (110) for fluidly connecting the interior of the tubular element (106) and the exterior of the tubular element.

Description

[Technical Field]

[0001] The present invention relates to an aerosol-generating article comprising an aerosol-forming substrate adapted such that upon heating of the aerosol-forming substrate, the aerosol-generating article generates an inhalable aerosol. [Background technology]

[0002] Aerosol-generating articles in which an aerosol-forming substrate, such as a tobacco-containing substrate, is heated rather than combusted are known in the art. Typically, in such heated aerosol-generating articles, an aerosol is generated by transferring heat from a heat source to a physically separated aerosol-forming substrate or material, which may be located in contact with, within, around, or downstream of the heat source. During use of the aerosol-generating article, volatile compounds are released from the aerosol-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 to form an aerosol.

[0003] It is known to provide aerosol-generating articles having one or more elements downstream of an aerosol-forming substrate configured to perform a specific function. For example, WO 2013 / 120565 A2 discloses an aerosol-generating article including 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 located immediately downstream of the aerosol-forming substrate, and an aerosol-cooling element made from a sheet of polylactic acid 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, these elements downstream of the aerosol-forming substrate can undesirably affect 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 lead to an unsatisfactory user experience.

[0005] It would be desirable to provide an aerosol-generating article having an element downstream of an aerosol-forming substrate that is capable of performing one or more of the above-mentioned functions while being relatively simple and inexpensive to manufacture. It would also be desirable for such an element to provide improved functionality over known prior art downstream elements. It would further be desirable for the RTD of the element to be controllable to provide a satisfactory RTD. Summary of the Invention

[0006] The present invention relates to an aerosol-generating article. The aerosol-generating article may comprise a first element. The first element may include an aerosol-forming substrate. The aerosol-generating article may further comprise a tubular element positioned downstream of the first element. The tubular element may have an end wall formed by a folded end of the tubular element. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 shows a schematic cross-sectional side view of an aerosol-generating article according to a first embodiment of the present invention. [Figure 2] FIG. 2 shows a perspective view of the tubular element of the aerosol-generating article of FIG. [Figure 3] 3A-3E show schematic cross-sectional side views illustrating stages in the formation of the tubular element of FIG. [Figure 4] FIG. 4 shows a schematic front view of an alternative tubular element according to an embodiment of the present invention. [Figure 5] FIG. 5 shows a schematic front view of a further alternative tubular element according to an embodiment of the present invention. [Figure 6] FIG. 6 shows a schematic cross-sectional side view of an aerosol-generating article according to a second embodiment of the present invention. [Figure 7] FIG. 7 shows a schematic cross-sectional side view of an aerosol-generating article according to a third embodiment of the present invention. [Figure 8] FIG. 8 shows a schematic cross-sectional side view of an aerosol-generating article according to a fourth embodiment of the present invention. [Figure 9] FIG. 9 shows a schematic cross-sectional side view of an aerosol-generating article according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] The end wall may define a plurality of openings for fluidly connecting the interior of the tubular element with the exterior of the tubular element.

[0009] The end wall may include a central region coaxial with the longitudinal axis of the tubular element. The end wall may include a peripheral region surrounding the central region. The end wall may define one or more openings for fluidly connecting the interior of the tubular element with the exterior of the tubular element. The total cross-sectional area of ​​the openings defined in the peripheral region of the end wall may be greater than the total cross-sectional area of ​​any openings defined in the central region of the end wall.

[0010] According to a first aspect of the present invention, there is provided an aerosol-generating article. The aerosol-generating article comprises a first element. The first element includes an aerosol-forming substrate. The aerosol-generating article further comprises a tubular element positioned downstream from the first element. The tubular element has an end wall formed by folded ends of the tubular element. The end wall defines a plurality of openings for fluidly connecting the interior of the tubular element with the exterior of the tubular element.

[0011] The tubular element of the present invention is particularly adapted to function as an aerosol cooling element. When the aerosol-forming substrate is heated, volatile compounds are released and entrained in the air drawn through the aerosol-generating article when a user inhales on the mouth end of the article. The tubular element is positioned downstream of the aerosol-forming substrate. Thus, as the 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 allows heat to be transferred from the air and volatile compounds to the relatively cool structure of the tubular element, which can then dissipate it into the environment.

[0012] By providing the tubular element with an end wall that defines multiple openings, air and volatile compounds form multiple flow paths as they pass between the interior of the tubular element and the exterior of the tubular element. These multiple flow paths may interact upstream and downstream of the end wall, which can result in increased turbulence within the tubular element. Advantageously, increased turbulence within the tubular element can increase the rate at which heat from the air and volatile compounds is transferred to the structure of the tubular element.

[0013] By providing the tubular element with an end wall that defines multiple openings rather than a single opening, the cross-sectional area of ​​each opening can be reduced while maintaining a satisfactory RTD. For example, the single opening can be replaced with two openings, each having half the cross-sectional area of ​​the single opening. Advantageously, this allows the tubular element to function as a filter, since the cross-sectional area of ​​the openings can be small enough to prevent undesirable components from being inhaled by the user. For example, the tubular element can prevent particles of the aerosol-forming substrate from passing through the end wall and thus further downstream, where they could be inhaled by the user.

[0014] By providing end walls formed from the folded ends of the tubular element, the tubular element can be configured to have a desired RTD through the size and shape of the end walls and the configuration of the multiple openings. In particular, the tubular element and its end walls can be efficiently and quickly manufactured with satisfactory RTD and low RTD between articles. Furthermore, the configuration of the tubular element and its end walls means that the RTD can be localized to a specific longitudinal location of the tubular element, rather than being continuously distributed along the length of the tubular element.

[0015] As used herein, the term "end wall" refers to the wall at the most upstream or most downstream end of a tubular element.

[0016] As used herein, the term "aerosol-generating article" means an article in which an aerosol-forming substrate is heated to generate an inhalable aerosol for delivery to a consumer.

[0017] As used herein, the term "aerosol-forming substrate" refers to a substrate that has the ability to release volatile compounds upon heating to generate an aerosol.

[0018] As used herein, the term "rod" refers to a generally cylindrical element of substantially polygonal cross-section, and preferably of circular, elliptical or oval cross-section.

[0019] As used herein, the term "longitudinal" refers to a direction corresponding to the major longitudinal axis of the aerosol-generating article extending between the upstream and downstream ends of the aerosol-generating article. During use, air is drawn longitudinally through the aerosol-generating article.

[0020] As used herein, the terms "upstream" and "downstream" describe the relative location 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.

[0021] The term "transverse" refers to a direction perpendicular to the longitudinal axis. References to a "cross section" of an aerosol-generating article or a component of an aerosol-generating article refer to a transverse cross section, unless otherwise specified.

[0022] The term "length" refers to the dimension of a component of an aerosol-generating article in its longitudinal direction. For example, it can be used to refer to the dimension of the aerosol-forming substrate or the first element, including the tubular element, in its longitudinal direction.

[0023] As used herein, the term "tubular element" is used to mean a generally elongated element that defines a lumen or airflow passage along its longitudinal axis. In particular, the term "tubular" is used hereinafter with reference to a tubular element that has a substantially cylindrical cross-section and defines at least one airflow conduit that establishes uninterrupted fluid communication between the upstream end of the tubular element and the downstream end of the tubular element. However, it will be appreciated that alternative shapes (e.g., alternative cross-sectional shapes) of the tubular element may be possible.

[0024] As used herein, the term "elongated" means that an element has a length dimension that is greater than its width dimension or its diameter dimension, e.g., more than twice its width dimension or its diameter dimension.

[0025] 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 ignites the end of the cigarette, and the resulting combustion produces inhalable smoke. In contrast, in heated aerosol-generating articles, the 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 the aerosol is generated by heat transfer from a combustible fuel element or heat source to a physically separated aerosol-forming material.

[0026] 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 use in an aerosol generation system comprising an electrically heated aerosol generator having an internal heater blade adapted to be inserted into an aerosol-forming substrate.

[0027] As used herein, the term "aerosol-generating device" refers to a device that includes a heater element that interacts with an aerosol-forming substrate of an aerosol-generating article to generate an aerosol.

[0028] The end wall may be located at the upstream end of the tubular element. In other words, the end wall may be an upstream end wall. In such a configuration, the air and volatile compounds pass through the multiple openings before entering the interior of the tubular element. This may promote turbulent flow downstream of the multiple openings and therefore within the interior of the tubular element. Advantageously, the turbulent flow may 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 may prevent undesirable components, such as solid substrate particles, from entering the interior of the tubular element, which may adversely affect the cooling and nucleation efficiency of the tubular element.

[0029] The end wall may be located at the downstream end of the tubular element. In other words, the end wall may be a downstream end wall. In such a configuration, the openings defined by the downstream end wall may act to accelerate, and thereby cool, the aerosol as it exits the tubular element.

[0030] The first element and the tubular element may be adjacent to each other. This may limit the extent to which undesirable components, such as tobacco particles, can pass downstream before being blocked by the end wall. This may also allow the aerosol to be cooled by the tubular element before interacting with any additional elements downstream of the first element. Advantageously, this may reduce the need for downstream elements formed from heat-resistant materials.

[0031] The term "adjacent" is used herein with respect to a tubular element and a first element to indicate that the tubular element is longitudinally positioned next to the first element. In particular, this term indicates that no other elements of the aerosol-generating article are longitudinally disposed between the first element and the tubular element.

[0032] 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 the aerosol-forming substrate, the tubular element may restrict downstream movement of the aerosol-forming substrate. For example, in embodiments having a downstream end wall, the tubular wall of the tubular element may contact the periphery of the first element or the aerosol-forming substrate, thereby restricting downstream movement. However, embodiments of tubular elements having an upstream end wall may be particularly effective in preventing downstream movement of the first element or the aerosol-forming substrate. 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 deformable than the end of a hollow cellulose acetate tube. The structure of the tubular element may also be better suited to withstand temperatures generated by a heating blade or susceptor element.

[0033] The first element and the tubular element may be adjacent to each other or may not be in contact with each other. A small gap of empty space may separate the first element and the tubular element from each other along the longitudinal axis of the aerosol-generating article. For example, the end wall of the tubular element may be adjacent to the aerosol-forming substrate or may not be in contact with the aerosol-forming substrate. The gap may be 2 millimeters or less. The gap may be 1 millimeter or less. Advantageously, such a gap may provide space for loose particles or fragments from the aerosol-forming substrate to coalesce during use of the aerosol-generating article.

[0034] The plurality of openings may be substantially equally spaced circumferentially. Equally spaced circumferentially between each of the plurality of openings helps ensure that the entire interior volume of the tubular element is used to cool the air and volatile compounds. Advantageously, this may lead to more efficient cooling of the air and volatile compounds. Preferably, the arc measurements between each of the plurality of openings are substantially equal. The arc measurements may be measured between the geometric centers of adjacent openings.

[0035] At least one of the plurality of openings may be radially spaced from the longitudinal axis of the tubular element. At least one of the plurality of openings may be radially spaced from the longitudinal axis of the tubular element by a radial distance.

[0036] The plurality of openings, or each of the plurality of openings, may be radially spaced from the longitudinal axis of the tubular element. The plurality of openings, or each of the plurality of openings, may be substantially equally radially spaced from the longitudinal axis of the tubular element. In some embodiments, each of the plurality of openings may be radially spaced a radial distance from the longitudinal axis of the tubular element. For example, the longitudinal axis of the tubular element may be positioned outside each of the plurality of openings. In other words, the longitudinal axis of the tubular element may not extend through any of the plurality of openings. In some other embodiments, the plurality of openings may be radially spaced an average radial distance from the longitudinal axis of the tubular element.

[0037] By spacing the openings radially from the longitudinal axis of the tubular element, the flow of air and volatile compounds can be closer to the tubular wall of the tubular element, which can advantageously improve heat transfer between the air, volatile compounds, and the tubular wall.

[0038] The radial distance may be at least 0.5 millimeters. The radial distance may be at least 0.8 millimeters. The radial distance may be at least 1 millimeter. The radial distance may be at least 1.2 millimeters. The radial distance may be at least 1.5 millimeters. The radial distance may be at least 1.8 millimeters. The radial distance may be at least 2 millimeters. The radial distance may be at least 2.5 millimeters.

[0039] The radial distance may be at least 1 percent of the diameter of the end wall. The radial distance may be at least 3 percent of the diameter of the end wall. The radial distance may be at least 5 percent of the diameter of the end wall. The radial distance may be at least 7 percent of the diameter of the end wall. The radial distance may be at least 10 percent of the diameter of the end wall. The radial distance may be at least 15 percent of the diameter of the end wall. The radial distance may be at least 20 percent of the diameter of the end wall. The radial distance may be at least 30 percent of the diameter of the end wall. The radial distance may be at least 40 percent of the diameter of the end wall.

[0040] The radial distance that an opening is spaced from the longitudinal axis of the tubular element is determined by the smallest distance from the longitudinal axis of the tubular element to the periphery of the opening.

[0041] Each of the plurality of openings may have a perimeter. At least a portion of the perimeter of each of the plurality of openings may be located less than 2 millimeters from the perimeter of the end wall. For example, less than 1.5 millimeters, less than 1 millimeter, less than 0.8 millimeters, less than 0.6 millimeters, less than 0.4 millimeters, less than 0.2 millimeters, or less than 0.1 millimeters. Preferably, the entire perimeter of each of the plurality of openings may be located less than 2 millimeters from the perimeter of the end wall. More preferably, the entire perimeter of each of the plurality of openings may be located less than 1 millimeter from the perimeter of the end wall.

[0042] The plurality of openings may coincide with the periphery of the end wall. For example, the periphery of the end wall may form at least a portion of the periphery of each of the plurality of openings. This means that the plurality of openings are immediately adjacent to the tubular wall of the tubular element. Advantageously, this may allow the air and volatile compounds flowing through the plurality of openings to be in intimate contact with the tubular wall of the tubular element, thereby increasing heat transfer between the air, volatile compounds, and the tubular wall of the tubular element. The plurality of openings may overlap the periphery of the end wall. In some embodiments in which the tubular element is surrounded by an outer wrapper, the outer wrapper may form at least a portion of the periphery of each of the plurality of openings.

[0043] The openings may be positioned to form an irregular pattern on the end wall, which may increase turbulence upstream or downstream of the openings, which may advantageously improve cooling of the air and volatile compounds.

[0044] 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.

[0045] Each of the plurality of openings may have an equivalent diameter of about 0.5 millimeters to about 5 millimeters. Each of the plurality of openings may have an equivalent diameter of about 0.8 millimeters to about 3 millimeters. Each of the plurality of openings may have an equivalent diameter of about 1 millimeter to about 2 millimeters. Each of the plurality of openings may have an equivalent diameter of about 2 millimeters to about 3 millimeters. Each of the plurality of openings may have an equivalent diameter of about 0.5 millimeters to about 5 millimeters.

[0046] Each of the plurality of openings may have an equivalent diameter of at least about 0.5 millimeters. Each of the plurality of openings may have an equivalent diameter of at least about 0.8 millimeters. Each of the plurality of openings may have an equivalent diameter of at least about 1 millimeter. Each of the plurality of openings may have an equivalent diameter of at least about 1.5 millimeters. Each of the plurality of openings may have an equivalent diameter of at least about 2 millimeters. Each of the plurality of openings may have an equivalent diameter of at least about 2.5 millimeters. Each of the plurality of openings may have an equivalent diameter of at least about 3 millimeters.

[0047] Each of the plurality of openings may have an equivalent diameter of about 5 millimeters or less. Each of the plurality of openings may have an equivalent diameter of about 3 millimeters or less. Each of the plurality of openings may have an equivalent diameter of about 2 millimeters or less. Advantageously, a plurality of openings having such equivalent diameters have been found to provide good filtration of solid particles while maintaining an acceptable RTD.

[0048] The plurality of openings may include at least 2 openings. The plurality of openings may include at least 4 openings. The plurality of openings may include at least 6 openings.

[0049] The plurality of openings may be a plurality of radially extending slits. The plurality of openings may be circular in shape. The plurality of openings may be oval in shape. The plurality of openings may be elliptical in shape. The plurality of openings may be rectangular in shape.

[0050] The end wall may define a substantially central opening. That is, there may be a plurality of openings as well as a substantially central opening. The substantially central opening may be coaxial with the longitudinal axis of the tubular element. The periphery of the substantially central opening may surround the longitudinal axis of the tubular element. The longitudinal axis of the tubular element may extend substantially through the central opening. The substantially central opening may be a single substantially central opening.

[0051] The substantially central opening may have an equivalent diameter of less than about 2 millimeters. Preferably, the substantially central opening may have an equivalent diameter of less than about 1.5 millimeters. More preferably, the substantially central opening may have an equivalent diameter of less than about 1.2 millimeters. Even more preferably, the substantially central opening may have an equivalent diameter of less than about 1 millimeter. Most preferably, the substantially central opening may have an equivalent diameter of less than about 0.8 millimeters.

[0052] The substantially central opening may be circular in shape. The substantially central opening may be oval in shape. The substantially central opening may be elliptical in shape. The substantially central opening may be rectangular in shape.

[0053] The plurality of openings may be positioned substantially around a central opening. The plurality of openings may be radially spaced from the substantially central opening.

[0054] The total cross-sectional area of ​​the plurality of openings may be greater than the cross-sectional area of ​​the substantially central opening. The total cross-sectional area of ​​the plurality of openings may be at least 200 percent of the cross-sectional area of ​​the substantially central opening. Preferably, the total cross-sectional area of ​​the plurality of openings may be at least 400 percent of the cross-sectional area of ​​the substantially central opening. The total cross-sectional area of ​​the plurality of openings may be at least 600 percent of the cross-sectional area of ​​the substantially central opening. The total cross-sectional area of ​​the plurality of openings may be at least 800 percent of the cross-sectional area of ​​the substantially central opening. The total cross-sectional area of ​​the plurality of openings may be at least 1000 percent of the cross-sectional area of ​​the substantially central opening.

[0055] The end wall may comprise a central region coaxial with the longitudinal axis of the tubular element. The end wall may comprise a peripheral region surrounding the central region. The peripheral region may be bounded by the periphery of the central region and the periphery of the end wall. The central region may be circular in shape.

[0056] The central region may have a diameter that is 70 percent or more of the diameter of the end wall. The central region may have a diameter that is 60 percent or more of the diameter of the end wall. The central region may have a diameter that is 50 percent or more of the diameter of the end wall. The central region may have a diameter that is 40 percent or more of the diameter of the end wall. The central region may have a diameter that is 30 percent or more of the diameter of the end wall. The central region may have a diameter that is 20 percent or more of the diameter of the end wall. The central region may have a diameter that is 10 percent or more of the diameter of the end wall.

[0057] In some embodiments, the cross-sectional area of ​​the central region is equal to the cross-sectional area of ​​the peripheral region.

[0058] The total cross-sectional area of ​​the openings defined in the peripheral region of the end wall may be greater than the total cross-sectional area of ​​any openings defined in the central region of the end wall.

[0059] The total cross-sectional area of ​​the openings defined in the peripheral region may be at least 60 percent of the total cross-sectional area of ​​all openings defined in the end wall, such as at least 70 percent, at least 80 percent, at least 90 percent, or at least 95 percent. In some embodiments, the total cross-sectional area of ​​the openings defined in the peripheral region may be 100 percent of the total cross-sectional area of ​​all openings defined in the end wall.

[0060] The plurality of openings may be defined in the peripheral region. A substantially central opening may be defined in the central region. Alternatively, the central region may be impermeable.

[0061] As described in more detail below, the aerosol-generating article may further include ventilation zones at locations along the tubular element. Advantageously, this may increase cooling of the air and volatile compounds within the interior of the tubular element by drawing in cooler ambient air. It may also increase turbulence within the tubular element, particularly if the ventilation zones draw air into the tubular element in a direction transverse to the longitudinal axis of the tubular element.

[0062] The tubular element may have a first end and a second end opposite the first end. The end wall may be a first end wall formed by a first folded end. The first end wall may be positioned at the first end of the tubular element. The tubular element may have a second end wall formed by a second folded end. 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 with the exterior of the tubular element. The opening defined by the second end wall may have an equivalent diameter 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 larger than the equivalent diameter of the opening defined in the first end wall.

[0063] As 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 a radially central axis of the aerosol-forming substrate. In such a configuration, the plurality of openings may be radially spaced from the susceptor element.

[0064] The tubular element may define a cavity. The cavity may extend from the upstream end of the tubular element to the downstream end of the tubular element. The cavity may be internal to the tubular element. The cavity may be substantially empty. A plurality of openings may be for fluidly connecting the cavity with the exterior of the tubular element. Each of the plurality of openings may be for fluidly connecting the cavity with the exterior of the tubular element.

[0065] The cavity may have a cross-sectional area that is at least 70 percent of the cross-sectional area of ​​the end wall. The cavity may have a cross-sectional area that is at least 80 percent of the cross-sectional area of ​​the end wall. The cavity may have a cross-sectional area that is at least 90 percent of the cross-sectional area of ​​the end wall. The cavity may have a cross-sectional area that is at least 95 percent of the cross-sectional area of ​​the end wall.

[0066] The aerosol-generating article may comprise a plurality of elements assembled in the form of a rod. The plurality of elements may comprise a first element and a tubular element.

[0067] The aerosol-generating article may include an outer wrapper surrounding at least the tubular element. The outer wrapper may define the outer surface of the aerosol-generating article. The outer wrapper may surround the first element. The outer wrapper may surround all of the multiple elements of the aerosol-generating article assembled in the form of a rod. The outer wrapper may be a tipping wrapper, as described below. The outer wrapper surrounding the tubular element may be a paper wrapper or a non-paper wrapper. Suitable paper wrappers for use in certain embodiments of the present invention are known in the art and include, but are not limited to, cigarette paper and filter plug wrap. Suitable non-paper wrappers for use in certain 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 material comprising multiple layers. Preferably, the wrapper is formed from an aluminum co-laminate sheet. The use of an aluminum-containing co-laminate sheet advantageously prevents combustion of the outer wrapper if the aerosol-forming substrate is ignited rather than heated in the intended manner.

[0068] The end wall may extend substantially transverse to the longitudinal direction of the aerosol-generating article.The end wall may extend substantially transverse to the longitudinal direction of the tubular element.

[0069] The end wall may extend partially into the interior of the tubular element. The end wall may form an angle of less than 90 degrees with the inner surface of the tubular element, more preferably an angle of less than 80 degrees with the inner surface of the tubular element, and even more preferably an angle of less than 70 degrees with the inner surface of the tubular element. This may be achieved by ensuring that a folding force is applied to the tubular element during manufacture such that at least a portion of the first end portion of the tubular element is forced into the interior of the tubular element. Such an arrangement may advantageously increase the likelihood that the end wall will remain stationary relative to the tubular element after the tubular element is manufactured. In particular, such an arrangement helps to overcome any natural elasticity of the material forming the tubular element, such that the folded end of the tubular element is less likely to return to its pre-folded state after manufacture.

[0070] The end walls may extend from a fold point on the tubular element towards a radially central location of the tubular element.

[0071] The material forming the end wall is preferably substantially 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.

[0072] The tubular element may have an outer diameter approximately equal to the outer diameter of the aerosol-generating article. Preferably, the tubular element has an outer diameter approximately equal to the outer diameter of the first element.

[0073] The tubular element may have an outer diameter of 5 millimeters to 11 millimeters. The tubular element may have an outer diameter of 6 millimeters to 10 millimeters, such as an outer diameter of 7 millimeters to 9 millimeters, or an outer diameter of 7.5 millimeters to 8.5 millimeters. In a preferred embodiment, the tubular element has an outer diameter of 7.8 millimeters ±10 percent. In another preferred embodiment, the tubular element has an outer diameter of 6 millimeters ±10 percent.

[0074] Preferably, the tubular element has an equivalent inner diameter of at least about 5.5 millimeters. More preferably, the elongated tubular element has an equivalent inner diameter of at least about 6 millimeters. Even more preferably, the elongated tubular element has an equivalent inner diameter of at least about 7 millimeters. The term "equivalent inner diameter" is used herein to refer to the diameter of a circle having the same surface area as the cross-section of the airflow conduit defined therein by the tubular element. The cross-section of the airflow conduit may have any suitable shape. However, as briefly mentioned above, a circular cross-section is preferred, i.e., the tubular element is a substantially cylindrical tube. In that case, the equivalent inner diameter of the tubular element substantially corresponds to the inner diameter of the cylindrical tube.

[0075] Preferably, the equivalent inner diameter of the tubular element is less than about 10 millimeters, more preferably less than about 9.5 millimeters, and even more preferably less than 9 millimeters.

[0076] Preferably, the tubular elements have a wall thickness of at least about 0.1 millimeters, and more preferably at least about 0.2 millimeters.

[0077] The tubular elements preferably have a wall thickness of less than about 1.5 millimeters, preferably less than about 1.25 millimeters. In one preferred embodiment, the tubular elements have a wall thickness of less than about 1 millimeter.

[0078] The tubular element therefore preferably has a wall thickness of from about 0.1 millimeters to about 1.5 millimeters, or from about 0.2 millimeters to about 1.25 millimeters, or from about 0.5 millimeters to about 1 millimeter.

[0079] Providing a tubular element with such a wall thickness can help improve the resistance of the tubular element to collapse or deformation, while allowing the end walls to be formed by the folded ends of the tubular element.

[0080] Preferably, the tubular element has a length of at least about 10 millimeters, more preferably at least about 15 millimeters.

[0081] The tubular element preferably has a length of less than about 30 millimeters, preferably less than about 25 millimeters, and more preferably less than about 20 millimeters.

[0082] The tubular elements may have a length of about 10 millimeters to about 30 millimeters, preferably about 15 millimeters to about 25 millimeters, and more preferably about 15 millimeters to about 20 millimeters. For example, in one particularly preferred embodiment, the tubular elements have a length of 18 millimeters.

[0083] The tubing elements may have a length of about 5 millimeters to about 20 millimeters, preferably about 8 millimeters to about 15 millimeters, and more preferably about 10 millimeters to about 13 millimeters. For example, in one particularly preferred embodiment, the tubing elements have a length of 12 millimeters.

[0084] The tubing element is preferably adapted to generate an RTD of from about 0 millimeters HO to about 80 millimeters HO, more preferably from about 20 millimeters HO to about 70 millimeters HO, and even more preferably from about 30 millimeters HO to about 70 millimeters HO. For example, the tubing element may be adapted to generate an RTD of from about 35 millimeters HO to about 70 millimeters HO.

[0085] The tubular element may be adapted to generate an RTD from approximately 0 millimeters H2O to approximately 20 millimeters H2O, more preferably from approximately 0 millimeters H2O to approximately 10 millimeters H2O.

[0086] The tubular element may be formed from a paper material, such as paper, paperboard, or cardboard. The tubular element may 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 may help improve the resistance of the tubular element to collapse or deformation, while allowing end walls to be formed by folded ends of the tubular element.

[0087] The tubular element may comprise at least two paper layers. The tubular element may preferably comprise less than 11 paper layers.

[0088] When 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 200 grams per square meter. Providing a tubular element with such a basis weight can help improve the resistance of the tubular element to collapse or deformation, while allowing the folded ends of the tubular element to form end walls.

[0089] The end wall of the tubular element may include a hydrophobic region comprising hydrophobic groups covalently bonded to the end wall. If the tubular element includes a second end wall, the second end wall may also include a hydrophobic region.

[0090] In another embodiment, 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 no more than about 40 g / m 2 or no more than about 35 g / m 2 .

[0091] The hydrophobic region may be produced by a process that includes applying a liquid composition containing a fatty acid halide to the surface of the end wall and maintaining the surface at a temperature of about 120 to about 180 degrees Celsius. The fatty acid halide reacts in situ with proton groups of the material in the hydrophobic region, resulting in the formation of a fatty acid ester.

[0092] The term "hydrophobic" refers to a surface that exhibits water-repellent properties. One useful way to determine this is to measure the water contact angle. The "water contact angle" is the angle, traditionally measured through a liquid, where the liquid / vapor interface meets the solid surface. It quantifies the wettability of a solid surface by a liquid via Young's equation.

[0093] The hydrophobic region has a Cobb water absorption (ISO 535:1991) value (at 60 seconds) of less than about 40 g / m 2 , less than about 35 g / m 2 , less than about 30 g / m 2 , or less than about 25 g / m 2 .

[0094] The hydrophobic region has a water contact angle of at least about 90 degrees, at least about 95 degrees, at least about 100 degrees, at least about 110 degrees, at least about 120 degrees, at least about 130 degrees, at least about 140 degrees, at least about 150 degrees, at least about 160 degrees, or at least about 170 degrees. Hydrophobicity is determined using the TAPPI T558 om-97 test, with results presented as interfacial contact angles, reported in degrees, which can range from approximately 0 degrees to approximately 180 degrees. If no contact angle is specified with the term hydrophobic, the water contact angle is at least 90 degrees.

[0095] The aerosol-generating article may comprise a downstream section at a location downstream of the first element, which may include one or more downstream elements, such as tubular elements.

[0096] The aerosol-generating article may comprise a mouthpiece element. The downstream section may include the mouthpiece element. The mouthpiece element may be located downstream of the tubular element. The mouthpiece element may be located immediately downstream of the tubular element. The mouthpiece element may abut 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.

[0097] The mouthpiece element may comprise at least one mouthpiece filter segment for filtering the aerosol generated from the aerosol-forming substrate. For example, the mouthpiece element may comprise one or more segments of fibrous filtering material. Suitable fibrous filtering materials are known to those skilled in the art. Preferably, the at least one mouthpiece filter segment comprises a cellulose acetate filter segment formed from cellulose acetate tow.

[0098] The mouthpiece element may consist of a single mouthpiece filter segment. In alternative embodiments, the mouthpiece element comprises two or more mouthpiece filter segments axially aligned in end-to-end relationship with one another.

[0099] The mouthpiece element may include 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.

[0100] The mouthpiece element may include a flavoring agent. The flavoring agent may be provided in any suitable form. For example, the mouthpiece element may comprise one or more capsules, beads, or granules of flavoring agent, or one or more threads or filaments loaded with flavoring agent.

[0101] Preferably, the mouthpiece element has a low particle filtration efficiency.

[0102] Preferably, the mouthpiece is formed from a segment of fibrous filtering material.

[0103] The mouthpiece element is preferably surrounded by plug wrap. Preferably, the mouthpiece element is non-ventilated so that air does not enter the aerosol-generating article through the mouthpiece element.

[0104] The mouthpiece element may be connected to one or more adjacent upstream components of the aerosol-generating article, such as a tubular element, by a tipping wrapper.

[0105] Preferably, the mouthpiece element has an RTD of less than about 25 millimeters HO. More preferably, the mouthpiece element has an RTD of less than about 20 millimeters HO. Even more preferably, the mouthpiece element has an RTD of less than about 15 millimeters HO.

[0106] RTD values ​​of about 10 millimeters HO to about 15 millimeters HO are particularly preferred, as a mouthpiece element having one such RTD is expected to contribute minimally to the overall RTD of the aerosol-generating article, thereby providing substantially no filtering effect on the aerosol delivered to the consumer.

[0107] 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 of about 5 millimeters to about 10 millimeters, or about 6 millimeters to about 8 millimeters. In a preferred embodiment, the mouthpiece element has an outer diameter of about 7.2 millimeters.

[0108] The mouthpiece element may have a length of at least about 10 millimeters, more preferably at least about 11 millimeters, more preferably at least about 12 millimeters. The mouthpiece element may have a length of less than about 25 millimeters, more preferably less than about 20 millimeters, more preferably less than about 15 millimeters.

[0109] The mouthpiece element may have a length of about 10 millimeters to about 25 millimeters, more preferably about 10 millimeters to about 20 millimeters, and even more preferably about 10 millimeters to about 15 millimeters. The mouthpiece element may have a length of about 11 millimeters to about 25 millimeters, more preferably about 11 millimeters to about 20 millimeters, and even more preferably about 11 millimeters to about 15 millimeters. The mouthpiece element may have a length of about 12 millimeters to about 25 millimeters, more preferably about 12 millimeters to about 20 millimeters, and even more preferably about 12 millimeters to about 20 millimeters.

[0110] In a preferred embodiment, the mouthpiece element has a length of approximately 12 millimeters.

[0111] Providing a relatively long mouthpiece element in the aerosol-generating article may allow for the inclusion of a capsule, or may allow the article to be more rigid where the user applies it to their lips, or both.

[0112] The aerosol-generating article may include a ventilation zone at a location along the downstream portion. The ventilation zone may be provided at a location along the tubular element. The characteristics of the ventilation zone are described below with respect to the aerosol-generating article. However, it will be understood that they may also be applied directly to the tubular element itself.

[0113] The ventilation zone may be located between about 5 millimeters and about 15 millimeters from the folded end of the tubular element. The ventilation zone may be located at least 2 millimeters from the folded end of the tubular element, more preferably at least 3 millimeters from the folded end of the tubular element, and even more preferably at least 5 millimeters from the folded end of the tubular element.

[0114] The ventilation zone may be located less than 20 millimeters from the folded end of the tubular element, more preferably less than 15 millimeters from the folded end of the tubular element, and even more preferably less than 10 millimeters from the folded end of the tubular element.

[0115] The ventilation zone may be located in the downstream section of the tubular element. Preferably, the ventilation zone is located from about 1 millimeter to about 10 millimeters from the downstream end of the tubular element, more preferably from about 2 millimeters to about 8 millimeters from the downstream end of the tubular element, and even more preferably from about 3 millimeters to about 6 millimeters from the downstream end of the first tubular element.

[0116] The ventilation zone may be located at least 1 millimeter from the downstream end of the tubular element, more preferably the ventilation zone is located at least 2 millimeters from the downstream end of the tubular element, and even more preferably the ventilation zone is located at least 3 millimeters from the downstream end of the tubular element.

[0117] The ventilation zone may be located less than 10 millimeters from the downstream end of the tubular element, more preferably the ventilation zone may be located less than 8 millimeters from the downstream end of the tubular element, and even more preferably the ventilation zone may be located less than 6 millimeters from the downstream end of the tubular element.

[0118] The ventilation zone may comprise a plurality of perforations through the peripheral wall of the vent element, which may be a tubular element. Preferably, the ventilation zone comprises at least one circumferential row of perforations. The ventilation zone may also comprise two circumferential rows of perforations. For example, the perforations may be formed during manufacture of the aerosol-generating article. Preferably, each circumferential row of perforations comprises between 8 and 30 perforations.

[0119] Aerosol-generating articles according to the present invention may have a breathability level of at least about 5 percent.

[0120] The term "ventilation level" is used throughout this specification to mean 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 greater the dilution of the aerosol stream delivered to the consumer.

[0121] Aerosol-generating articles may typically have a breathability level of at least about 10 percent, preferably at least about 15 percent, and more preferably at least about 20 percent.

[0122] In preferred embodiments, the aerosol-generating article has a breathability level of at least about 25 percent. Preferably, the aerosol-generating article has a breathability level of less than about 60 percent. The aerosol-generating article may have a breathability level of about 45 percent or less. More preferably, the aerosol-generating article may have a breathability level of about 40 percent or less, and even more preferably, about 35 percent or less.

[0123] In particularly preferred embodiments, the aerosol-generating article has a ventilation level of about 30 percent. The aerosol-generating article may have a ventilation level of about 20 percent to about 60 percent, preferably about 20 percent to about 45 percent, and more preferably about 20 percent to about 40 percent. The aerosol-generating article may have a ventilation level of about 25 percent to about 60 percent, preferably about 25 percent to about 45 percent, and more preferably about 25 percent to about 40 percent. In further embodiments, the aerosol-generating article has a ventilation level of about 30 percent to about 60 percent, preferably about 30 percent to about 45 percent, and more preferably about 30 percent to about 40 percent.

[0124] In some preferred embodiments, the aerosol-generating article has a breathability level of about 28 percent to about 42 percent. In some particularly preferred embodiments, the aerosol-generating article has a breathability level of about 30 percent.

[0125] Embodiments in which ventilation zones are provided at locations along the tubular elements may provide a number of advantages. For example, without wishing to be bound by theory, the inventors have found that the temperature reduction caused by admitting cooler ambient air into the tubular elements through the ventilation zones can have a beneficial effect on aerosol particle nucleation and growth.

[0126] The formation of aerosols from gaseous mixtures containing various chemical species depends on a delicate interplay between nucleation, evaporation, condensation, and even fusion, which accounts for changes in vapor concentration, temperature, and velocity fields. The so-called classical nucleation theory is based on the assumption that a fraction of molecules in the gas phase are large enough to remain coherent for a long time with a sufficient probability (e.g., a 50 / 50 chance). These molecules represent a certain kind of critical, threshold molecular cluster within the transient molecular aggregates, meaning that smaller molecular clusters generally tend to break down into the gas phase rather quickly, while larger clusters generally tend to grow. These critical clusters are identified as primary nucleation cores from which droplets are expected to grow due to the condensation of molecules from the vapor. It is assumed that freshly nucleated, virgin droplets emerge with a certain original diameter and may subsequently grow by several orders of magnitude. This may be facilitated and enhanced by the rapid cooling of the surrounding vapor, which induces condensation. In this regard, it is helpful to remember that evaporation and condensation are two aspects of one and the same mechanism: gas-liquid mass transfer. Evaporation involves the net mass transfer from the droplets to the gas phase, while condensation is the net mass transfer from the gas phase to the droplet phase. Evaporation (or condensation) causes the droplets to shrink (or grow), but the number of droplets remains the same.

[0127] In this scenario (when the scenario is further complicated by fusion phenomena), the temperature and rate of cooling may play an important role in determining how the system responds. In general, because the nucleation process is typically nonlinear, different cooling rates may lead to significantly different temperature behaviors with respect to the formation of the liquid phase (droplets). Without wishing to be bound by theory, it is hypothesized that cooling can cause a rapid increase in the number of condensed droplets, followed by a short-term, strong increase in this growth (nucleation burst). This nucleation burst appears to be more pronounced at lower temperatures. Furthermore, it appears that a faster cooling rate may favor the onset of early nucleation. In contrast, a decrease in the cooling rate appears to have a favorable effect on the final size that the aerosol droplets ultimately reach.

[0128] Thus, the rapid cooling induced by admitting ambient air into the tubular element via the ventilation zone can be used to favor favorable nucleation and growth of aerosol droplets. At the same time, however, admitting ambient air into the tubular element has the direct drawback of diluting the aerosol stream delivered to the consumer.

[0129] The inventors have surprisingly found that the dilution effect on the aerosol (which can be assessed, inter alia, by measuring the effect on the delivery of the aerosol former (e.g., glycerol) contained in the aerosol-forming substrate) is advantageously minimized at aeration levels within the aforementioned ranges. In particular, aeration levels of 25 percent to 50 percent, and even more preferably 28 to 42 percent, have been found to lead to particularly satisfactory glycerin delivery values. At the same time, the degree of nucleation, and consequently the delivery of nicotine and aerosol former (e.g., glycerol), is enhanced.

[0130] The inventors have surprisingly found that the favorable effects of enhanced nucleation promoted by the rapid cooling induced by the introduction of ventilation air into the article can significantly counteract the undesirable effects of dilution. Thus, satisfactory values ​​of aerosol delivery are consistently achieved by aerosol-generating articles in accordance with the present disclosure.

[0131] This is particularly advantageous for "short" aerosol-generating articles, such as those in which the length of the first element comprising the aerosol-generating substrate is less than about 40 millimeters, preferably less than 25 millimeters, and even more preferably less than 20 millimeters, or the total length of the aerosol-generating article is less than about 70 millimeters, preferably less than about 60 millimeters, and even more preferably less than 50 millimeters. As will be appreciated, in such aerosol-generating articles, there is little time and space for aerosol formation and for the particle phase of the aerosol to become available for delivery to the consumer.

[0132] Furthermore, because the vented tubular element can be configured so as not to substantially contribute to the overall RTD of the aerosol-generating article, the overall RTD of the article can be advantageously fine-tuned in such an aerosol-generating article by adjusting the length and density of the first element comprising the aerosol-forming substrate, or the length, optionally the length and density, of the segment of filtering material forming part of the mouthpiece, or the length and density of the element provided upstream of the first element comprising the aerosol-forming substrate. Thus, aerosol-generating articles having a predetermined RTD can be consistently and precisely manufactured, thereby providing a satisfactory level of RTD for the consumer, even in the presence of ventilation.

[0133] Furthermore, the inventors have found that promoting mixing of the hot air from the aerosol-forming substrate with fresh air from the vents drawn through the vent holes is achieved when providing a vent in a tubular element with end walls formed by folded ends of the tubular element, the end walls defining a plurality of openings for fluidly connecting the interior of the tubular element with the exterior of the tubular element. Without intending to be bound by theory, it is believed that in particular the combination of the partial airflow restriction created by the end walls and the presence of incoming air from the vents may be particularly effective in promoting mixing of the fresh air drawn through the vent holes with the hot air drawn through the aerosol-forming substrate.

[0134] 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 upstream of the first element.

[0135] The first element including the aerosol-forming substrate may further include a susceptor element located 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.

[0136] As used herein, the term "susceptor element" refers to a material capable of converting electromagnetic energy into heat. When located within a varying electromagnetic field, induced eddy currents in the susceptor element cause the susceptor element to heat. When the elongated susceptor element is positioned in thermal contact with the aerosol-forming substrate, the aerosol-forming substrate is heated by the susceptor element.

[0137] The term "elongated" when used to describe a susceptor element means that the susceptor element has a length dimension that is greater than its width dimension or its thickness dimension, for example, more than twice its width dimension or its thickness dimension.

[0138] The susceptor elements may be disposed substantially longitudinally within the aerosol-forming substrate. This means that the length dimension of the elongated susceptor elements is disposed approximately parallel to the longitudinal axis of the aerosol-forming substrate, for example, within ±10 degrees of parallel to the longitudinal axis of the aerosol-forming substrate. In a preferred embodiment, the elongated susceptor elements may be positioned at a radially central position within the aerosol-forming substrate and extend along the longitudinal axis of the aerosol-forming substrate.

[0139] In embodiments in which the aerosol-generating article is in the form of a rod, the susceptor elements are substantially longitudinally disposed within the rod. This means that the length dimension of the elongated susceptor elements is disposed approximately parallel to the longitudinal axis of the rod, e.g., within ±10 degrees of parallel to the longitudinal axis of the rod. In preferred embodiments, the elongated susceptor elements may be positioned at a radially central position within the rod and extend along the longitudinal axis of the rod.

[0140] 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.

[0141] The susceptor elements are preferably in the form of pins, rods, strips or blades.

[0142] The susceptor element preferably has a length of about 5 millimeters to about 15 millimeters, such as, for example, about 6 millimeters to about 12 millimeters, or about 8 millimeters to about 10 millimeters.

[0143] The ratio of the length of the susceptor element to the overall length of the aerosol-generating article may be from about 0.2 to about 0.35.

[0144] 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, and 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, and even more preferably less than about 0.3.

[0145] The ratio of the length of the susceptor element to the total length of the aerosol-generating article may be about 0.22 to about 0.34, more preferably about 0.24 to about 0.34, and even more preferably about 0.26 to about 0.34. The ratio of the length of the susceptor element to the total length of the aerosol-generating article may be about 0.22 to about 0.32, more preferably about 0.24 to about 0.32, and even more preferably about 0.26 to about 0.32. In a further embodiment, the ratio of the length of the susceptor element to the total length of the aerosol-generating article is preferably about 0.22 to about 0.3, more preferably about 0.24 to about 0.3, and even more preferably about 0.26 to about 0.3.

[0146] In a particularly preferred embodiment, the ratio of the length of the susceptor element to the overall length of the aerosol-generating article is about 0.27.

[0147] The susceptor element preferably has a width of about 1 millimeter to about 5 millimeters.

[0148] The susceptor element may generally have a thickness of about 0.01 millimeters to about 2 millimeters, for example, about 0.5 millimeters to about 2 millimeters. The susceptor element may have a thickness of about 10 micrometers to about 500 micrometers, and more preferably about 10 micrometers to about 100 micrometers.

[0149] When the susceptor element has a constant cross-section, for example a circular cross-section, it has a preferred width or diameter of about 1 millimeter to about 5 millimeters.

[0150] When the susceptor elements have the form of strips or blades, the strips or blades preferably have a rectangular shape, preferably having a width of about 2 millimeters to about 8 millimeters, more preferably about 3 millimeters to about 5 millimeters. As an example, a susceptor element in the form of a blade strip may have a width of about 4 millimeters.

[0151] When the susceptor elements are in the form of strips or blades, the strips or blades preferably have a rectangular shape and a thickness of about 0.03 millimeters to about 0.15 millimeters, more preferably about 0.05 millimeters to about 0.09 millimeters. As an example, a susceptor element in the form of a blade strip may have a thickness of about 0.07 millimeters.

[0152] In a preferred embodiment, the elongated susceptor elements are in the form of strips or blades, preferably having a rectangular shape and a thickness of about 55 micrometers to about 65 micrometers.

[0153] More preferably, the elongated susceptor elements have a thickness of about 57 micrometers to about 63 micrometers. Even more preferably, the elongated susceptor elements have a thickness of about 58 micrometers to about 62 micrometers. In a particularly preferred embodiment, the elongated susceptor elements have a thickness of about 60 micrometers.

[0154] The elongated susceptor elements preferably have a length that is the same as or shorter than the length of the aerosol-forming substrate. Preferably, the elongated susceptor elements have the same length as the aerosol-forming substrate.

[0155] The susceptor element may be formed from any material that can be inductively heated to a temperature sufficient to generate an aerosol from the aerosol-forming substrate. Preferred susceptor elements comprise metal or carbon.

[0156] Preferred susceptor elements may include or consist of a ferromagnetic material, such as a ferromagnetic alloy, 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 grade 410, grade 420, or grade 430 stainless steel. Different materials dissipate different amounts of energy when placed in electromagnetic fields of similar frequency and field strength.

[0157] Thus, any of the susceptor element parameters, such as type of material, length, width, and thickness, can be varied to provide a desired power distribution within a known electromagnetic field. Preferred susceptor elements may be heated to temperatures in excess of 250 degrees Celsius.

[0158] Suitable susceptor elements may include a non-metallic core having a metal layer, such as a metal band formed on the surface of the ceramic core. The susceptor element may have a protective outer layer, such as a protective ceramic or glass layer, encapsulating the susceptor element. The susceptor element may include a protective coating formed of glass, ceramic, or an inert metal formed over a core of susceptor element material.

[0159] The susceptor element is placed in thermal contact with the aerosol-forming substrate, such that as the temperature of the susceptor element increases, the aerosol-forming substrate is heated and an aerosol is formed. Preferably, the susceptor element is placed in direct physical contact with the aerosol-forming substrate, for example, within the aerosol-forming substrate.

[0160] The susceptor element may be a multi-material susceptor element and may comprise a first susceptor element material and a second susceptor element material. The first susceptor element material is disposed 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 is preferably primarily used to heat the susceptor element when the susceptor element is placed in a fluctuating electromagnetic field. Any suitable material may be used. For example, the first susceptor element material may be aluminum or an iron-based material such as stainless steel. The second susceptor element material is preferably primarily used to indicate when the susceptor element reaches 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.

[0161] The heating of the aerosol-forming substrate and the temperature control of the heating can be separated by providing a susceptor element having at least first and second susceptor element materials with a second susceptor element material having a Curie temperature and a first susceptor element material having no Curie temperature, or by providing first and second susceptor element materials having different first and second Curie temperatures. The first susceptor element material is preferably a magnetic material having a Curie temperature greater than 500°C. From the standpoint of heating efficiency, it is desirable that the Curie temperature of the first susceptor element material exceed any maximum temperature to which the susceptor element can be heated. The second Curie temperature may be selected to be preferably lower than 400°C, preferably lower than 380°C, or even lower than 360°C. The second susceptor element material is preferably a magnetic material selected to have a second Curie temperature substantially equal to the desired maximum heating temperature. That is, the second Curie temperature is preferably approximately the same as the temperature to which the susceptor element must be heated to generate an aerosol from the aerosol-forming substrate. The second Curie temperature may be, for example, within the range of 200° C. to 400° C., or within the range of 250° C. to 360° C. The second Curie temperature of the second susceptor element material may be selected such that the overall average temperature of the aerosol-forming substrate does not exceed 240° C. when heated by a susceptor element having a temperature equal to the second Curie temperature.

[0162] The aerosol-forming substrate may be in the form of a rod.The aerosol-forming substrate may be a solid aerosol-forming substrate.

[0163] In certain preferred embodiments, the aerosol-forming substrate comprises homogenized plant material, preferably homogenized tobacco material.

[0164] As used herein, the term "homogenized plant material" encompasses any plant material formed by agglomeration of plant particles. For example, a sheet or web of homogenized tobacco material for the aerosol-forming substrate of the present invention may be formed by agglomerating particles of tobacco material obtained by grinding, crushing, or comminuting plant material and, optionally, one or more of tobacco lamina and tobacco stems. Homogenized plant material may be produced by casting, extrusion, a papermaking process, or any other suitable process known in the art.

[0165] The homogenized plant material may be provided in any suitable form. For example, the homogenized plant material may be in the form of one or more sheets. As used herein, the term "sheet" describes a thin layer of material having a width and length substantially greater than its thickness. The homogenized plant material may be in the form of a plurality of pellets or granules. The homogenized plant material may also be in the form of a plurality of strands, pieces, or fragments. As used herein, the term "strand" describes an elongated element of material having a length substantially greater than its width and thickness. The term "strand" should be considered to encompass pieces, fragments, and any other homogenized plant material having a similar form. The strands of homogenized plant material may be formed from a sheet of homogenized plant material, for example, by cutting or chopping, or by other methods, such as extrusion.

[0166] The strands may be formed in situ within the aerosol-forming substrate as a result of splitting or cracking of the sheet of homogenized plant material during the formation of the aerosol-forming substrate, for example, as a result of crimping. The strands of homogenized plant material within the aerosol-forming substrate may be separated from one another. At least some strands of homogenized plant material within the aerosol-forming substrate may be at least partially connected to adjacent strands along their length. For example, adjacent strands may be connected by one or more fibers. This may occur, for example, when strands are formed due to splitting of the sheet of homogenized plant material during the manufacture of the aerosol-forming substrate, as described above.

[0167] The aerosol-forming substrate is preferably in the form of one or more sheets of homogenized plant material. The one or more sheets of homogenized plant material may be produced by a casting process. The one or more sheets of homogenized plant material may be produced by a paper-making process. The one or more sheets described herein may each individually have a thickness of 100 micrometers to 600 micrometers, preferably 150 micrometers to 300 micrometers, and most preferably 200 micrometers to 250 micrometers. Individual thickness refers to the thickness of an individual sheet, while combined thickness refers to the total thickness of all sheets comprising the aerosol-forming substrate. For example, if the aerosol-forming substrate is formed from two individual sheets, the combined thickness is the thickness of the two individual sheets or the sum of the measured thicknesses of the two sheets when the two sheets are stacked within the aerosol-forming substrate.

[0168] One or more of the sheets described herein can each individually have a basis weight of from about 100 g / m2 to about 300 g / m2.

[0169] One or more of the sheets described herein may each individually have a density of from about 0.3 g / cm 3 to about 1.3 g / cm 3 , and preferably have a density of from about 0.7 g / cm 3 to about 1.0 g / cm 3 .

[0170] In embodiments in which the aerosol-forming substrate comprises one or more sheets of homogenized plant material, the sheets are preferably in the form of an assembly of one or more sheets. As used herein, the term "assembly" means that the sheets of homogenized plant material are coiled, folded, or otherwise compressed or contracted in a direction substantially transverse to the cylindrical axis of the plug or rod.

[0171] One or more sheets of homogenized plant material may be gathered transversely to their longitudinal axes and surrounded by a wrapper to form a continuous rod or plug.

[0172] One or more sheets of homogenized plant material may advantageously be crimped or similarly treated. As used herein, the term "crimped" means a sheet having a plurality of substantially parallel ridges or corrugations. Alternatively or additionally to being crimped, one or more sheets of homogenized plant material may be embossed, debossed, perforated, or otherwise deformed to provide texture to one or both sides of the sheet.

[0173] Preferably, each sheet of homogenized plant material may be crimped to have a plurality of ridges or corrugations substantially parallel to the cylindrical axis of the plug. This process advantageously facilitates assembling the crimped sheets of homogenized plant material to form a plug. Preferably, one or more sheets of homogenized plant material may be assembled. Of course, the crimped sheets of homogenized plant material may alternatively or additionally have a plurality of substantially parallel ridges or corrugations that form acute or obtuse angles with respect to the cylindrical axis of the plug. The sheet may be crimped to an extent that the integrity of the sheet is interrupted at the plurality of parallel ridges or corrugations, causing separation of the material and resulting in the formation of fragments, strands, or pieces of homogenized plant material.

[0174] One or more sheets of homogenized plant material may be cut into strands, as mentioned above. The aerosol-forming substrate may contain multiple strands of homogenized plant material. The strands may be used to form plugs. Typically, the width of such strands is about 5 millimeters, about 4 millimeters, about 3 millimeters, or about 2 millimeters or less. The length of the strands may be greater than about 5 millimeters, about 5 millimeters to about 15 millimeters, about 8 millimeters to about 12 millimeters, or about 12 millimeters. Preferably, the strands have substantially the same length as each other. The length of the strands may be determined by the manufacturing process by which the rod is cut into shorter plugs, and the length of the strands corresponds to the length of the plugs. Strands are fragile and may break, especially during transport. In such cases, the length of some of the strands may be shorter than the length of the plugs.

[0175] The strands preferably extend substantially longitudinally along the length of the aerosol-forming substrate, aligned with the longitudinal axis, and thus preferably aligned substantially parallel to one another.

[0176] The homogenized plant material may contain up to about 95 weight percent plant particles on a dry weight basis, preferably up to about 90 weight percent plant particles, more preferably up to about 80 weight percent plant particles, more preferably up to about 70 weight percent plant particles, more preferably up to about 60 weight percent plant particles, and even more preferably up to about 50 weight percent plant particles on a dry weight basis.

[0177] For example, the homogenized plant material can contain, on a dry weight basis, from about 2.5 weight percent to about 95 weight percent plant particles, or from about 5 weight percent to about 90 weight percent plant particles, or from about 10 weight percent to about 80 weight percent plant particles, or from about 15 weight percent to about 70 weight percent plant particles, or from about 20 weight percent to about 60 weight percent plant particles, or from about 30 weight percent to about 50 weight percent plant particles.

[0178] The homogenized plant material may be a homogenized tobacco material comprising tobacco particles. The sheets of homogenized tobacco material used in such embodiments may have a tobacco content of at least about 40 weight percent on a dry weight basis, more preferably at least about 50 weight percent on a dry weight basis, even more preferably at least about 70 weight percent on a dry weight basis, and most preferably at least about 90 weight percent on a dry weight basis.

[0179] The term "tobacco particles" refers to particles of any plant member of the genus Nicotiana. The term "tobacco particles" encompasses ground or powdered tobacco lamina, ground or powdered tobacco stems, tobacco dust, tobacco fines, and other particulate tobacco by-products formed during tobacco processing, handling, and shipping. In preferred embodiments, the tobacco particles are derived substantially entirely from tobacco lamina. In contrast, isolated nicotine and nicotine salts, although tobacco-derived compounds, are not considered tobacco particles for purposes of the present invention and are not included in the proportion of particulate plant material.

[0180] The tobacco particles may be prepared from one or more tobacco plant varieties. Any type of tobacco may be used in the blend. Examples of tobacco types that may be used include, but are not limited to, sun-cured tobacco, flue-cured tobacco, burley tobacco, Maryland tobacco, Orient tobacco, Virginia tobacco, and other specialty tobaccos.

[0181] Flame-curing is a tobacco curing method used specifically with Virginia tobacco. During the flue-curing process, heated air is circulated through tightly packed tobacco. During the first stage, the tobacco leaves yellow and wither. During the second stage, the leaf lamina dries completely. During the third stage, the leaf stem dries completely.

[0182] Burley tobacco plays an important role in many tobacco blends. It has a unique flavor and aroma and the ability to absorb large amounts of casing.

[0183] Orient is a type of tobacco with small leaves and high aromatic qualities. However, Orient tobacco has a milder flavor than, for example, Burley. Therefore, Orient tobacco is generally used in relatively small proportions in tobacco blends.

[0184] Kasturi, Madura, and Jatim are subtypes of sun-cured tobacco that can be used. Preferably, Kasturi and flue-cured tobaccos are blended to produce tobacco particles. Thus, the tobacco particles in the particulate plant material can comprise a blend of Kasturi and flue-cured tobaccos.

[0185] The tobacco particles may have a nicotine content of at least about 2.5 weight percent on a dry weight basis. More preferably, the tobacco particles may have a nicotine content of at least about 3 weight percent on a dry weight basis, even more preferably at least about 3.2 weight percent, even more preferably at least about 3.5 weight percent, and most preferably at least about 4 weight percent.

[0186] The homogenized plant material may include tobacco particles combined with non-tobacco plant flavor particles. Preferably, the non-tobacco plant flavor particles are selected from one or more of ginger, rosemary, eucalyptus, clove, and star anise particles. Preferably, in such embodiments, the homogenized plant material comprises, on a dry weight basis, at least about 2.5 weight percent of non-tobacco plant flavor particles, with the remaining plant particles being tobacco particles. Preferably, the homogenized plant material comprises, on a dry weight basis, at least about 4 weight percent of non-tobacco plant flavor particles, more preferably at least about 6 weight percent of non-tobacco plant flavor particles, more preferably at least about 8 weight percent of non-tobacco plant flavor particles, and more preferably at least about 10 weight percent of non-tobacco plant flavor particles. Preferably, the homogenized plant material comprises, on a dry weight basis, at most about 20 weight percent of non-tobacco plant flavor particles, more preferably at most about 18 weight percent of non-tobacco plant flavor particles, and more preferably at most about 16 weight percent of non-tobacco plant flavor particles.

[0187] The weight ratio of non-tobacco plant flavor particles and tobacco particles in the particulate plant material forming the homogenized plant material can vary depending on the desired flavor characteristics and composition of the aerosol generated from the aerosol-forming substrate during use. Preferably, the homogenized plant material comprises, on a dry weight basis, a weight ratio of non-tobacco plant flavor particles to tobacco particles of at least 1:30, more preferably a weight ratio of non-tobacco plant flavor particles to tobacco particles of at least 1:20, more preferably a weight ratio of non-tobacco plant flavor particles to tobacco particles of at least 1:10, and most preferably a weight ratio of non-tobacco plant flavor particles to tobacco particles of at least 1:5.

[0188] The homogenized plant material may include cannabis particles. The term "cannabis particles" refers to particles of the cannabis plant, such as Cannabis sativa, Cannabis indica, and Cannabis ruderalis.

[0189] The homogenized plant material preferably comprises no more than 95 weight percent particulate plant material on a dry weight basis. Accordingly, the particulate plant material is typically combined with one or more other ingredients to form the homogenized plant material.

[0190] The homogenized plant material may further comprise a binder for modifying the mechanical properties of the particulate plant material, wherein the binder is included in the homogenized plant material during production as described herein. Suitable exogenous binders known to those skilled in the art are known in the art and include, but are not limited to, gums such as guar gum, xanthan gum, gum arabic, and locust bean gum; cellulose binders such as hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, and ethyl cellulose; polysaccharides such as starch, organic acids such as alginic acid, sodium alginate, agar, and conjugate base salts of organic acids such as pectin, and combinations thereof. Preferably, the binder comprises guar gum.

[0191] The binder may be present in an amount of about 1 weight percent to about 10 weight percent based on the dry weight of the homogenized plant material, preferably in an amount of about 2 weight percent to about 5 weight percent based on the dry weight of the homogenized plant material.

[0192] The homogenized plant material may further include one or more lipids to enhance the diffusion rate of the volatile components (e.g., aerosol formers, gingerol, and nicotine), where the lipids are included in the homogenized plant material during the processes described herein. Suitable lipids for inclusion in the homogenized plant material include, but are not limited to, medium chain triglycerides, cocoa butter, palm oil, palm kernel oil, mango oil, shea 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.

[0193] The homogenized plant material may further include a pH modifier.

[0194] The homogenized plant material may further include fibers to alter the mechanical properties of the homogenized plant material, where the fibers are included in the homogenized plant material during the manufacturing process described herein. Suitable exogenous fibers for inclusion in the homogenized plant material are known in the art and include fibers formed from non-tobacco and non-ginger materials, including, but not limited to, cellulose fibers, soft wood fibers, hard wood 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 "particulate plant material" defined above. Before being included in the homogenized plant material, the fibers may be processed by a suitable process known in the art, including, but not limited to, mechanical pulping, refining, chemical pulping, bleaching, sulfate pulping, and combinations thereof. Typically, the fibers have a length greater than their width.

[0195] Suitable fibers are typically greater than 400 micrometers and have a length of 4 millimeters or less, with lengths in the range of 0.7 millimeters to 4 millimeters being preferred. The fibers are preferably present in an amount of about 2 weight percent to about 15 weight percent, most preferably about 4 weight percent, based on the dry weight of the substrate.

[0196] The homogenized plant material may further include one or more aerosol formers. Upon volatilization, the aerosol formers may carry other vaporized compounds, such as nicotine and flavorants, that are released from the aerosol-forming substrate upon heating. Suitable aerosol formers for inclusion in the homogenized plant material are known in the art and include, but are not limited to, polyhydric alcohols (such as triethylene glycol, propylene glycol, 1,3-butanediol, and glycerol), esters of polyhydric alcohols (such as glycerol mono-, di-, or triacetate), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate and tetradecanedioate).

[0197] The homogenized plant material may have an aerosol former content of from about 5 weight percent to about 30 weight percent on a dry weight basis, such as from about 10 weight percent to about 25 weight percent on a dry weight basis, or from about 15 weight percent to about 20 weight percent on a dry weight basis.

[0198] For example, when the substrate is intended for use in an aerosol-generating article for an electrically-operated aerosol-generating system having a heating element, the aerosol former content may preferably be about 5 weight percent to about 30 weight percent on a dry weight basis.When the substrate is intended for use in an aerosol-generating article for an electrically-operated aerosol-generating system having a heating element, the aerosol former is preferably glycerol.

[0199] The homogenized plant material may have an aerosol former content of about 1 percent to about 5 percent by weight on a dry weight basis. For example, if the substrate is intended for use in an aerosol-generating article in which the aerosol former is held in a reservoir separate from the substrate, the substrate may have an aerosol former content greater than 1 percent and less than about 5 percent. In such embodiments, the aerosol former volatilizes upon heating, and the aerosol former stream contacts the aerosol-forming substrate so as to incorporate flavors from the aerosol-forming substrate into the aerosol.

[0200] The homogenized plant material may have an aerosol former content of about 30 weight percent to about 45 weight percent. This relatively high level of aerosol former is particularly suitable for aerosol-forming substrates intended to be heated at temperatures below 275 degrees Celsius. In such embodiments, the homogenized plant material preferably further comprises, on a dry weight basis, about 2 weight percent to about 10 weight percent of a cellulose ether and, on a dry weight basis, about 5 weight percent to about 50 weight percent of additional cellulose. The use of a combination of a cellulose ether and additional cellulose has been found to provide particularly effective aerosol delivery when used in an aerosol-forming substrate having an aerosol former content of 30 weight percent to 45 weight percent.

[0201] Suitable cellulose ethers include, but are not limited to, methyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, hydroxyl ethyl cellulose, hydroxyl propyl cellulose, ethyl hydroxyl ethyl cellulose and carboxymethyl cellulose (CMC). In a particularly preferred embodiment, the cellulose ether is carboxymethyl cellulose.

[0202] As used herein, the term "additional cellulose" encompasses any cellulose material incorporated into the homogenized plant material that is not derived from the non-tobacco plant particles or tobacco particles provided in the homogenized plant material. Thus, the additional cellulose is incorporated into the homogenized plant material as a separate and distinct cellulose source in addition to the non-tobacco plant material or tobacco material, relative to any cellulose inherently provided within the non-tobacco plant particles or tobacco particles. The additional cellulose is typically derived from a plant different from the non-tobacco plant particles or tobacco particles. Preferably, the additional cellulose is in the form of an inert cellulose material that is sensorily inert and therefore does not substantially affect the sensory properties of the aerosol generated from the aerosol-forming substrate. For example, the additional cellulose is preferably a tasteless and odorless material.

[0203] The additional cellulose may include cellulose powder, cellulose fiber, or a combination thereof.

[0204] The aerosol former may act as a wetting agent in the aerosol-forming substrate.

[0205] The wrapper surrounding the rod of homogenized plant material can be a paper wrapper or a non-paper wrapper. Suitable paper wrappers for use in certain embodiments of the present invention are known in the art and include, but are not limited to, cigarette paper and filter plug wrap. Suitable non-paper wrappers for use in certain 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 wrapper may be formed from a laminate material comprising multiple layers. Preferably, the wrapper is formed from an aluminum co-laminate sheet. The use of an aluminum-containing co-laminate sheet advantageously prevents combustion of the aerosol-forming substrate if the aerosol-forming substrate is to be ignited rather than heated in the intended manner.

[0206] In some preferred embodiments, the aerosol-forming substrate comprises a gel composition comprising an alkaloid compound, or a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound, hi particularly preferred embodiments, the aerosol-forming substrate comprises a gel composition comprising nicotine.

[0207] Preferably, the gel composition comprises an alkaloid compound, or a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound, an aerosol former, and at least one gelling agent. Preferably, the at least one gelling agent forms a solid medium, the glycerol is dispersed in the solid medium, and the alkaloid or cannabinoid is dispersed in the glycerol. Preferably, the gel composition is in a stable gel phase.

[0208] Advantageously, the stable gel composition comprising nicotine provides a predictable composition shape upon storage or during transition from manufacture to consumer. The stable gel composition comprising nicotine substantially maintains its shape. The stable gel composition comprising nicotine does not substantially release a liquid phase upon storage or during transition from manufacture to consumer. The stable gel composition comprising nicotine may provide a simple consumable design. The consumable may not need to be designed to contain a liquid, and therefore a wider range of materials and container configurations may be contemplated.

[0209] The gel compositions described herein may be combined with an aerosol generating device to provide nicotine aerosol to the lungs at inhalation or airflow rates within those of traditional smoking. The aerosol generating device may continuously heat the gel composition. The consumer may take multiple inhalations or "puffs," with each "puff" delivering a quantity of nicotine aerosol. Upon heating, the gel composition may deliver a high-nicotine / low total particulate matter (TPM) aerosol to the consumer, preferably in a continuous manner.

[0210] 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 cannot substantially release or absorb water (sweat) when exposed to standard temperatures and pressures while varying relative humidity from about 10 percent to about 60 percent. For example, a stable gel can substantially maintain its shape and mass when exposed to standard temperatures and pressures while varying relative humidity from about 10 percent to about 60 percent.

[0211] The gel composition may contain an alkaloid compound, or a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound. The gel composition may contain one or more alkaloids. The gel composition may contain one or more cannabinoids. The gel composition may contain a combination of one or more alkaloids and one or more cannabinoids.

[0212] The term "alkaloid compound" refers to any class of naturally occurring organic compounds containing one or more basic nitrogen atoms. Generally, alkaloids contain at least one nitrogen atom in an amine-type structure. This or another nitrogen atom within the molecule of an alkaloid compound can be active as a base in an acid-base reaction. Most alkaloid compounds have one or more of their nitrogen atoms as part of a ring system, such as a heterocycle. In nature, alkaloid compounds are found primarily in plants and are particularly common in certain families of flowering plants. However, some alkaloid compounds are found in animal species and fungi. In this disclosure, the term "alkaloid compound" refers to both naturally occurring and synthetically produced alkaloid compounds.

[0213] The gel composition preferably comprises an alkaloid compound selected from the group consisting of nicotine, anatabine, and combinations thereof.

[0214] Preferably, the gel composition comprises nicotine.

[0215] The term "nicotine" refers to nicotine and nicotine derivatives (eg, free base nicotine, nicotine salts, and the like).

[0216] The term "cannabinoid compounds" refers to any one of a class of naturally occurring compounds found in parts of the cannabis plant, including Cannabis sativa, Cannabis indica, and Cannabis ruderalis. Cannabinoid compounds are particularly concentrated in the female flower heads. Cannabinoid compounds that occur naturally in cannabis plants include cannabidiol (CBD) and tetrahydrocannabinol (THC). In this disclosure, the term "cannabinoid compounds" is used to describe both naturally occurring and synthetically produced cannabinoid compounds.

[0217] The gel may comprise a cannabinoid compound selected from the group consisting of cannabidiol (CBD), tetrahydrocannabinol (THC), tetrahydrocannabinolic acid (THCA), cannabidiolic acid (CBDA), cannabinol (CBN), cannabigerol (CBG), cannabichromene (CBC), cannabicyclol (CBL), cannabivarin (CBV), tetrahydrocannabivarin (THCV), cannabidivarin (CBDV), cannabichromevarin (CBCV), cannabigerovarin (CBGV), cannabigerol monomethyl ether (CBGM), cannabielsoin (CBE), cannabicitran (CBT), and combinations thereof.

[0218] The gel composition may preferably comprise a cannabinoid compound selected from the group consisting of cannabidiol (CBD), THC (tetrahydrocannabinol) and combinations thereof.

[0219] The gel may preferably contain cannabidiol (CBD).

[0220] The gel composition may include nicotine and cannabidiol (CBD).

[0221] The gel composition may include nicotine, cannabidiol (CBD), and THC (tetrahydrocannabinol).

[0222] The gel composition preferably contains about 0.5 to about 10 weight percent alkaloid compounds, or about 0.5 to about 10 weight percent cannabinoid compounds, or a total of about 0.5 to about 10 weight percent alkaloid and cannabinoid compounds. The gel composition may contain about 0.5 to about 5 weight percent alkaloid compounds, or about 0.5 to about 5 weight percent cannabinoid compounds, or a total of about 0.5 to about 5 weight percent alkaloid and cannabinoid compounds. The gel composition preferably contains about 1 to about 3 weight percent alkaloid compounds, or about 1 to about 3 weight percent cannabinoid compounds, or a total of about 1 to about 3 weight percent alkaloid and cannabinoid compounds. The gel composition may preferably contain about 1.5 weight percent to about 2.5 weight percent alkaloid compounds, or about 1.5 weight percent to about 2.5 weight percent cannabinoid compounds, or a total amount of about 1.5 weight percent to about 2.5 weight percent alkaloid compounds and cannabinoid compounds. The gel composition may preferably contain about 2 weight percent alkaloid compounds, or about 2 weight percent cannabinoid compounds, or a total amount of about 2 weight percent alkaloid compounds and cannabinoid compounds. The alkaloid compound component of the gel formulation may be the most volatile component of the gel formulation. In some embodiments, 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. The cannabinoid compound component of the gel formulation may be the most volatile component of the gel formulation. In some embodiments, 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.

[0223] Preferably, nicotine is included in the gel composition. Nicotine can be added to the composition in free base or salt form. The gel composition contains about 0.5 weight percent to about 10 weight percent nicotine, or about 0.5 weight percent to about 5 weight percent nicotine. Preferably, the gel composition contains about 1 weight percent to about 3 weight percent nicotine, or about 1.5 weight percent to about 2.5 weight percent nicotine, or about 2 weight percent nicotine. The nicotine component of the gel formulation can be the most volatile component of the gel formulation. In some embodiments, 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.

[0224] The gel composition preferably includes an aerosol former. Ideally, the aerosol former is substantially resistant to thermal degradation at the operating temperature of the associated aerosol-generating device. Suitable aerosol formers include, but are not limited to, polyhydric alcohols (such as triethylene glycol, 1,3-butanediol, and glycerin), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids (such as dimethyl dodecanedioate and dimethyl tetradecanedioate). The polyhydric alcohol or mixture thereof may be one or more of triethylene glycol, 1,3-butanediol, and glycerin (glycerol or propane-1,2,3-triol) or polyethylene glycol. The aerosol former is preferably glycerol.

[0225] The gel composition comprises a majority of the aerosol former. The gel composition may comprise a mixture of water and aerosol former, with the aerosol former forming a majority (by weight) of the gel composition. The aerosol former may form at least about 50 weight percent of the gel composition. The aerosol former may form at least about 60 weight percent, or at least about 65 weight percent, or at least about 70 weight percent of the gel composition. The aerosol former may form about 70 weight percent to about 80 weight percent of the gel composition. The aerosol former may form about 70 weight percent to about 75 weight percent of the gel composition.

[0226] The gel composition may comprise a majority of glycerol. The gel composition may comprise a mixture of water and glycerol, with glycerol forming the majority (by weight) of the gel composition. Glycerol may form at least about 50 weight percent of the gel composition. Glycerol may form at least about 60 weight percent, or at least about 65 weight percent, or at least about 70 weight percent of the gel composition. Glycerol may form about 70 weight percent to about 80 weight percent of the gel composition. Glycerol may form about 70 weight percent to about 75 weight percent of the gel composition.

[0227] The gel composition preferably includes at least one gelling agent. The gel composition preferably includes a total amount of gelling agents ranging from about 0.4 weight percent to about 10 weight percent. More preferably, the composition includes gelling agents in a range of about 0.5 weight percent to about 8 weight percent. More preferably, the composition includes gelling agents in a range of about 1 weight percent to about 6 weight percent. More preferably, the composition includes gelling agents in a range of about 2 weight percent to about 4 weight percent. More preferably, the composition includes gelling agents in a range of about 2 weight percent to about 3 weight percent.

[0228] The term "gelling agent" refers to a compound that, when homogeneously added in an amount of about 0.3 weight percent to a 50 weight percent water / 50 weight percent glycerol mixture, forms a solid medium or support matrix leading to a gel. Gelling agents include, but are not limited to, hydrogen-bond cross-linking gelling agents and ionic cross-linking gelling agents.

[0229] The gelling agent may comprise one or more biopolymers, which may be formed from polysaccharides.

[0230] Examples of biopolymers include gellan gum (natural gellan gum, low acyl gellan gum, high acyl gellan gum, and low acyl gellan gum are preferred), xanthan gum, alginate (alginic acid), agar, and guar gum. It may be preferable for the composition to include xanthan gum. The composition may include two biopolymers. The composition may include three biopolymers. The composition may include two biopolymers in substantially equal amounts by weight. The composition may include three biopolymers in substantially equal amounts by weight.

[0231] Preferably, the gel composition contains at least about 0.2 weight percent of a hydrogen-bond cross-linked gelling agent. The gel composition preferably contains at least about 0.2 weight percent of an ionic cross-linked gelling agent. Most preferably, the gel composition contains at least about 0.2 weight percent of a hydrogen-bond cross-linked gelling agent and at least about 0.2 weight percent of an ionic cross-linked gelling agent. The gel composition may contain from about 0.5 weight percent to about 3 weight percent of a hydrogen-bond cross-linked gelling agent and from about 0.5 weight percent to about 3 weight percent of an ionic cross-linked gelling agent, or from about 1 weight percent to about 2 weight percent of a hydrogen-bond cross-linked gelling agent and from about 1 weight percent to about 2 weight percent of an ionic cross-linked gelling agent. The hydrogen-bond cross-linked gelling agent and the ionic cross-linked gelling agent may be present in substantially equal amounts in the gel composition.

[0232] The term "hydrogen-bond cross-linking gelator" refers to a gelator that forms non-covalent or physical cross-links via hydrogen bonds. Hydrogen bonds are not covalent bonds to hydrogen atoms, but rather a type of electrostatic dipole-dipole attraction between molecules. They result from the attraction between a hydrogen atom covalently bonded to another extremely electronegative atom, such as an N, O, or F atom, and another extremely electronegative atom.

[0233] The hydrogen-bond cross-linking gelling agent may comprise one or more of galactomannan, gelatin, agarose, or konjac gum, or agar. Preferably, the hydrogen-bond cross-linking gelling agent comprises agar.

[0234] The gel composition preferably contains from about 0.3 weight percent to about 5 weight percent of the hydrogen-bond cross-linking gelling agent. Preferably, the composition contains from about 0.5 weight percent to about 3 weight percent of the hydrogen-bond cross-linking gelling agent. Preferably, the composition contains from about 1 weight percent to about 2 weight percent of the hydrogen-bond cross-linking gelling agent.

[0235] The gel composition may contain galactomannan in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the galactomannan may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the galactomannan may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the galactomannan may be in the range of about 1 weight percent to about 2 weight percent.

[0236] The gel composition may contain gelatin in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the gelatin may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the gelatin may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the gelatin may be in the range of about 1 weight percent to about 2 weight percent.

[0237] The gel composition may contain agarose in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the agarose may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the agarose may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the agarose may be in the range of about 1 weight percent to about 2 weight percent.

[0238] The gel composition may contain konjac gum in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the konjac gum may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the konjac gum may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the konjac gum may be in the range of about 1 weight percent to about 2 weight percent.

[0239] The gel composition may contain agar in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the agar may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the agar may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the agar may be in the range of about 1 weight percent to about 2 weight percent.

[0240] The term "ionically cross-linking gelator" refers to a gelator that forms non-covalent or physical cross-links through ionic bonds. Ionic cross-linking involves the association of polymer chains through non-covalent interactions. A cross-linked network is formed when multivalent molecules with opposite charges are electrostatically attracted to each other, resulting in a cross-linked polymer network.

[0241] The ionic cross-linking gelling agent may include low acyl gellan, pectin, kappa carrageenan, iota carrageenan or alginate. Preferably, the ionic cross-linking gelling agent may include low acyl gellan.

[0242] The gel composition may comprise an ionically cross-linked gelling agent in the range of about 0.3 weight percent to about 5 weight percent. Preferably, the composition comprises an ionically cross-linked gelling agent in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the composition comprises an ionically cross-linked gelling agent in the range of about 1 weight percent to about 2 weight percent.

[0243] The gel composition may contain low acyl gellan in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the low acyl gellan may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the low acyl gellan may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the low acyl gellan may be in the range of about 1 weight percent to about 2 weight percent.

[0244] The gel composition may comprise pectin in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the pectin may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the pectin may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the pectin may be in the range of about 1 weight percent to about 2 weight percent.

[0245] The gel composition may comprise kappa carrageenan in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the kappa carrageenan may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the kappa carrageenan may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the kappa carrageenan may be in the range of about 1 weight percent to about 2 weight percent.

[0246] The gel composition may comprise iota carrageenan in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the iota carrageenan may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the iota carrageenan may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the iota carrageenan may be in the range of about 1 weight percent to about 2 weight percent.

[0247] The gel composition may comprise alginate in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the alginate may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the alginate may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the alginate may be in the range of about 1 weight percent to about 2 weight percent.

[0248] The gel composition may contain a hydrogen-bond cross-linking gelator and an ionic cross-linking gelator in a ratio of about 3:1 to about 1:3. Preferably, the gel composition may contain a hydrogen-bond cross-linking gelator and an ionic cross-linking gelator in a ratio of about 2:1 to about 1:2. Preferably, the gel composition may contain a hydrogen-bond cross-linking gelator and an ionic cross-linking gelator in a ratio of about 1:1.

[0249] The gel composition may further comprise a thickening agent. The thickening agent in combination with the hydrogen-bond cross-linking gelling agent and the ionic cross-linking gelling agent surprisingly appears to support a solid medium and maintain the gel composition even when the gel composition contains high levels of glycerol.

[0250] The term "thickener" refers to a compound that, when uniformly added in an amount of 0.3 weight percent to a 50 weight percent water / 50 weight percent glycerol mixture at 25 degrees Celsius, increases the viscosity without resulting in the formation of a gel, and causes the mixture to remain fluid. Preferably, a thickener refers to a compound that, when uniformly added in an amount of 0.3 weight percent to a 50 weight percent water / 50 weight percent glycerol mixture at 25 degrees Celsius, increases the 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 resulting in the formation of a gel, and causes the mixture to remain fluid. Preferably, a thickener refers to a compound that, when homogeneously added in an amount of 0.3 weight percent to a 50 weight percent water / 50 weight percent glycerol mixture at 25 degrees Celsius, increases the viscosity at a shear rate of 0.1 s-1 by at least 2 times, at least 5 times, at least 10 times, or at least 100 times greater than before addition without resulting in the formation of a gel, and the mixture becomes or remains fluid.

[0251] The viscosity values ​​provided herein may be measured using a Brookfield RVT viscometer with a disc type RV#2 spindle rotating at 25 degrees Celsius at a speed of 6 revolutions per minute (rpm).

[0252] The gel composition preferably comprises a thickening agent in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the composition comprises a thickening agent in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the composition comprises a thickening agent in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the composition comprises a thickening agent in the range of about 1 weight percent to about 2 weight percent.

[0253] The thickening agent may comprise one or more of xanthan gum, carboxymethylcellulose, microcrystalline cellulose, methylcellulose, gum arabic, guar gum, lambda carrageenan, or starch. Preferably, the thickening agent may comprise xanthan gum.

[0254] The gel composition may contain xanthan gum in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the xanthan gum may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the xanthan gum may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the xanthan gum may be in the range of about 1 weight percent to about 2 weight percent.

[0255] The gel composition may contain carboxymethylcellulose in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the carboxymethylcellulose may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the carboxymethylcellulose may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the carboxymethylcellulose may be in the range of about 1 weight percent to about 2 weight percent.

[0256] The gel composition may contain microcrystalline cellulose in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the microcrystalline cellulose may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the microcrystalline cellulose may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the microcrystalline cellulose may be in the range of about 1 weight percent to about 2 weight percent.

[0257] The gel composition may contain methylcellulose in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the methylcellulose may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the methylcellulose may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the methylcellulose may be in the range of about 1 weight percent to about 2 weight percent.

[0258] The gel composition may include gum arabic in the range of about 0.2 weight percent to about 5 weight percent. Preferably, gum arabic may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, gum arabic may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, gum arabic may be in the range of about 1 weight percent to about 2 weight percent.

[0259] The gel composition may contain guar gum in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the guar gum may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the guar gum may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the guar gum may be in the range of about 1 weight percent to about 2 weight percent.

[0260] The gel composition may comprise lambda carrageenan in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the lambda carrageenan may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the lambda carrageenan may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the lambda carrageenan may be in the range of about 1 weight percent to about 2 weight percent.

[0261] The gel composition may comprise starch in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the starch may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the starch may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the starch may be in the range of about 1 weight percent to about 2 weight percent.

[0262] The gel composition may further comprise a divalent cation. Preferably, the divalent cation comprises calcium ions, such as calcium lactate in solution. The divalent cation (e.g., calcium ions) may aid in gel formation in compositions that include a gelling agent, such as an ionically crosslinking gelling agent. Ionic effects may aid gel formation. The divalent cation may be present in the gel composition in a range of about 0.1 to about 1 weight percent, or about 0.5 weight percent.

[0263] The gel composition may further comprise an acid. The acid may comprise a carboxylic acid. The carboxylic acid may comprise a ketone group. Preferably, the carboxylic acid may comprise a ketone group having less than about 10 carbon atoms, such as levulinic acid or lactic acid, or less than about 6 carbon atoms, or less than about 4 carbon atoms. Preferably, the carboxylic acid has three carbon atoms (such as lactic acid). Lactic acid surprisingly improves the stability of the gel composition over similar carboxylic acids. The carboxylic acid may aid in gel formation. The carboxylic acid may reduce changes in the alkaloid compound concentration, or cannabinoid compound concentration, or both the alkaloid compound concentration and the cannabinoid compound concentration in the gel composition during storage. The carboxylic acid may reduce changes in the nicotine concentration in the gel composition during storage.

[0264] The gel composition may include a carboxylic acid in the range of about 0.1 weight percent to about 5 weight percent. Preferably, the carboxylic acid may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the carboxylic acid may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the carboxylic acid may be in the range of about 1 weight percent to about 2 weight percent.

[0265] The gel composition may contain lactic acid in the range of about 0.1 weight percent to about 5 weight percent. Preferably, the lactic acid may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the lactic acid may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the lactic acid may be in the range of about 1 weight percent to about 2 weight percent.

[0266] The gel composition may include levulinic acid in the range of about 0.1 weight percent to about 5 weight percent. Preferably, the levulinic acid may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the levulinic acid may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the levulinic acid may be in the range of about 1 weight percent to about 2 weight percent.

[0267] The gel composition preferably contains some water. When the composition contains some water, the gel composition is more stable. The gel composition preferably contains at least about 1 weight percent, or at least about 2 weight percent, or at least about 5 weight percent water. The gel composition preferably contains at least about 10 weight percent or at least about 15 weight percent water.

[0268] The gel composition preferably contains about 8 weight percent to about 32 weight percent water. The gel composition preferably contains about 15 weight percent to about 25 weight percent water. The gel composition preferably contains about 18 weight percent to about 22 weight percent water. The gel composition preferably contains about 20 weight percent water.

[0269] Preferably, the aerosol-forming substrate contains from about 150 mg to about 350 mg of the gel composition.

[0270] 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 a gel composition is that the gel composition is retained within the porous medium, which may aid in 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.

[0271] The term "porous" is used herein to refer to a material that provides a plurality of pores or openings that allow the passage of air through the material.

[0272] The porous medium may be any suitable porous material capable of holding or retaining the gel composition. Ideally, the porous medium allows the gel composition to move within. In certain embodiments, the porous medium comprises natural, synthetic, or semi-synthetic materials, or a combination thereof. In certain embodiments, the porous medium comprises a sheet material, a foam, or a fiber, e.g., loose fiber, or a combination thereof. In certain embodiments, the porous medium comprises a woven fabric, a nonwoven fabric, or an 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, e.g., cotton or cellulose acetate. In a particularly preferred embodiment, the porous medium comprises a sheet made from cotton fibers.

[0273] The porous medium may be crimped or chopped. In a preferred embodiment, the porous medium is crimped. In an alternative embodiment, the porous medium comprises chopped porous medium. The crimping or chopping process can be before or after loading with the gel composition.

[0274] Crimping the sheet material has the advantage of improving the structure and allowing passageways through the structure. The passageways through the crimped sheet material aid in gel loading, gel retention, and fluid passage through the crimped sheet material. Therefore, there are advantages to using crimped sheet materials as porous media.

[0275] The shredding provides the medium with a high surface area to volume ratio so that it can readily absorb the gel.

[0276] In certain embodiments, the sheet material is a composite material. Preferably, the sheet material is porous. The sheet material may aid in the manufacture of the tubular element containing the gel. The sheet material may aid in the introduction of an active agent into the tubular element containing the gel. The sheet material may help stabilize the structure of the tubular element containing the gel. The sheet material may aid in the transportation or storage of the gel. The use of the sheet material allows or aids in adding structure to the porous medium, for example, by crimping the sheet material.

[0277] The porous medium can be a thread. The thread can include, for example, cotton, paper, or acetate tow. The thread can also be loaded with a gel, like any other porous medium. An advantage of using thread as the porous medium is that it can aid in ease of manufacturing.

[0278] 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 manufacturing, the thread may be impregnated with gel and stored ready to be used for inclusion in the assembly of tubular elements.

[0279] Preferably, in embodiments in which the first component comprises a gel composition, as described above, the tubular component has a length of less than 10 millimeters. The use of such a relatively short tubular component in combination with the gel composition may optimize delivery of the aerosol to the consumer.

[0280]

[0013] Embodiments of the present invention in which the aerosol-forming substrate comprises the gel composition described above preferably include 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 can also advantageously compensate for potential decreases in RTD due to evaporation of the gel composition, for example, when the first element comprising the aerosol-forming substrate is heated during use.

[0281] According to a second aspect of the present invention, there is provided an aerosol-generating article. The aerosol-generating article comprises a first element. The first element includes an aerosol-forming substrate. The aerosol-generating article further comprises a tubular element positioned downstream of the first element. The tubular element has an end wall formed by folded ends of the tubular element. The end wall has a central region coaxial with the longitudinal axis of the tubular element and a peripheral region surrounding the central region. The end wall defines one or more openings for fluidly connecting the interior of the tubular element with the exterior of the tubular element. The total cross-sectional area of ​​the openings defined in the peripheral region of the end wall is greater than the total cross-sectional area of ​​any openings defined in the central region of the end wall.

[0282] According to a third aspect of the present invention, there is provided a method for forming a tubular element for an aerosol-generating article as described herein. The method may include providing a precursor tubular element in the form of a tube of material defining an internal passageway, and applying a folding force to the precursor tubular element to bend or fold a first end of the precursor tubular element about a folding point, the folding force being applied such that at least a portion of the first end of the precursor tubular element extends into the internal passageway. The method may further include releasing the folding force such that the first end of the tubular element partially returns along its folding path to a position where the first end extends substantially transverse to a longitudinal axis of the precursor tubular element, thereby forming an end wall at the end of the tubular element. The method may further include perforating the end wall to form a plurality of openings in the end wall.

[0283] 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 an electrical element for heating an aerosol-forming substrate.

[0284] The aerosol generating device may include a power source. The power source may be configured to provide power to the electrical elements. The power source may be any suitable power source, for example, 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 (e.g., a lithium-cobalt battery, a lithium iron phosphate battery, a lithium titanate battery, or a lithium polymer battery).

[0285] The electrical element may be a heating element. The heating element may be disposed within or around the heating chamber to heat an aerosol-generating article insertable into the heating chamber. The heating chamber may be hollow.

[0286] The aerosol-generating device may comprise an internal heating element, which may be provided with, for example, a pin or blade that is inserted at least partially 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.

[0287] 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 such as polyimide. The flexible heating foils may be shaped to fit the periphery of the heating chamber. Alternatively, the external heating element may take the form of one or more metal grids, flexible printed circuit boards, molded circuit components (MIDs), ceramic heating elements, flexible carbon fiber heating elements, or may be formed using coating techniques such as plasma deposition on a suitably shaped substrate.

[0288] It will be appreciated that any feature described with respect to one aspect of the invention or disclosure is equally applicable to any other aspect of the invention or disclosure. [Example]

[0289] The present invention is defined in the claims. However, below is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of any other example, embodiment, or aspect described herein.

[0290] Example 1 An aerosol-generating article, comprising: a first element comprising an aerosol-forming substrate; a tubular element positioned downstream of the first element, the tubular element having an end wall formed by a folded end of the tubular element; An aerosol-generating article, wherein the end wall defines a plurality of openings for fluidly connecting the interior of the tubular element with the exterior of the tubular element. Example 2. 10. The aerosol-generating article of example 1, wherein the first element and the tubular element are adjacent to each other. Example 3. 3. An aerosol-generating article according to any one of claims 1 to 2, wherein the end wall of the tubular element is adjacent to and in contact with the aerosol-forming substrate. Example 4. An aerosol-generating article according to any one of Examples 1 to 3, wherein the end wall is an upstream end wall. Example 5. An aerosol-generating article as described in example 4, wherein the upstream end wall provides a barrier that limits downstream movement of the aerosol-forming substrate. Example 6 An aerosol-generating article according to any one of Examples 1 to 5, wherein the plurality of openings are substantially equally circumferentially spaced apart. Example 7 7. An aerosol-generating article according to any one of Examples 1 to 6, wherein at least one of the plurality of openings is spaced radially from the longitudinal axis of the tubular element by a radial distance. Example 8 7. An aerosol-generating article according to any one of Examples 1 to 6, wherein each of the plurality of openings is spaced radially from the longitudinal axis of the tubular element by a radial distance. Example 9. An aerosol-generating article according to any one of Examples 1 to 6, wherein the plurality of openings are spaced apart radially from the longitudinal axis of the tubular element by an average radial distance. Example 10. An aerosol-generating article according to any one of Examples 7 to 9, wherein the radial distance is at least 0.5 millimeters. Example 11 An aerosol-generating article according to any one of Examples 7 to 9, wherein the radial distance is at least 1 percent of the diameter of the end wall. Example 12 An aerosol-generating article described in any of Examples 1 to 11, wherein each of the plurality of openings has a periphery, and at least a portion of the periphery of each of the plurality of openings is positioned less than 2 millimeters from the periphery of the end wall. Example 13 An aerosol-generating article according to any one of Examples 1 to 12, wherein the plurality of openings coincide with the periphery of the end wall. Example 14. An aerosol-generating article according to any one of Examples 1 to 13, wherein the end walls further define a substantially central opening. Example 15. An aerosol-generating article as described in Example 14, wherein the plurality of openings are positioned substantially around a central opening. Example 16. 16. An aerosol-generating article as described in Example 14 or 15, wherein the plurality of openings have a total cross-sectional area substantially greater than the cross-sectional area of ​​the central opening. Example 17. An aerosol-generating article as described in Example 16, wherein the total cross-sectional area of ​​the multiple openings is substantially at least 200 percent of the cross-sectional area of ​​the central opening. Example 18. 18. An aerosol-generating article according to any one of Examples 1 to 17, wherein the end wall comprises a central region coaxial with the longitudinal axis of the tubular element, and the end wall comprises a peripheral region surrounding the central region. Example 19. An aerosol-generating article as described in Example 18, wherein the central region has a diameter that is 30 percent or more of the diameter of the end wall. Example 20. 20. An aerosol-generating article as described in Example 18 or 19, wherein the total cross-sectional area of ​​the openings defined in the peripheral region of the end wall is greater than the total cross-sectional area of ​​any openings defined in the central region of the end wall. Example 21. An aerosol-generating article described in any of Examples 18 to 20, wherein the total cross-sectional area of ​​the openings defined in the peripheral region is at least 60 percent of the total cross-sectional area of ​​all openings defined in the end wall. Example 22. 22. The aerosol-generating article of any one of Examples 18 to 21, wherein a plurality of openings are defined in the peripheral region. Example 23. An aerosol-generating article according to any one of Examples 1 to 22, wherein the tubular element has a length of at least about 15 millimeters. Example 24. An aerosol-generating article according to any one of Examples 1 to 23, wherein the tubular element is adapted to generate a resistance to draw (RTD) of between approximately 35 millimeters HO and approximately 70 millimeters HO. Example 25. 25. The aerosol-generating article of any one of Examples 1 to 24, further comprising a mouthpiece element positioned downstream of the tubular element. Example 26. An aerosol-generating article according to any one of Examples 1 to 25, further comprising ventilation zones at locations along the tubular element. Example 27. 27. The aerosol-generating article of Example 26, wherein the ventilation zone comprises a plurality of perforations through the peripheral wall of the tubular element. Example 28. The aerosol-generating article of any one of Examples 1 to 27, wherein the first element comprises a susceptor element disposed substantially longitudinally within the aerosol-forming substrate.

[0291] The embodiments will now be further described with reference to the figures.

[0292] 1 shows an aerosol-generating article 1 according to a first embodiment of the present invention. The aerosol-generating article 1 comprises a first element 11 including an aerosol-forming substrate 12 and a downstream section 14 located downstream of the first element 11. The aerosol-generating article 1 further comprises an upstream section 16 located upstream of the first element 11. The aerosol-generating article 1 may therefore extend from an upstream or distal end 18 to a downstream or oral end 20.

[0293] The aerosol-generating article has a total length of about 45 millimeters.

[0294] The downstream section 14 comprises a tubular element 100 located immediately downstream of the first element 11 and in longitudinal alignment with the first element 11. In the embodiment of Figure 1, the upstream end of the tubular element 100 abuts the downstream end of the first element 11, in particular the downstream end of the aerosol-forming substrate 12.

[0295] Additionally, the downstream section 14 includes a mouthpiece element 42 at a location downstream of the tubular element 100. More specifically, the mouthpiece element 42 is positioned immediately downstream of the tubular element 100. As shown in FIG. 1 , the upstream end of the mouthpiece element 42 abuts the downstream end of the tubular element 100.

[0296] Mouthpiece element 42 is provided in the form of a cylindrical plug of low-density cellulose acetate. Mouthpiece element 42 has a length of approximately 12 millimeters and an outer diameter of approximately 7.25 millimeters. The RTD of mouthpiece element 42 is approximately 12 millimeters HO.

[0297] The aerosol-generating article 1 includes a ventilation zone 60 provided at a location along the tubular element 100. More specifically, the ventilation zone is located approximately 4 millimeters from the downstream end of the tubular element 100. The ventilation level of the aerosol-generating article 10 is approximately 40 percent. While ventilation zones provide various advantages as discussed above, it will be understood that the following embodiments may not include ventilation zones.

[0298] The first element 11 is in the form of a rod including 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 rod 11. The rod 11 may further include a wrapper (not shown) surrounding the aerosol-forming substrate 12. The rod 11 including the aerosol-forming substrate has an outer diameter of about 7.25 millimeters and a length of about 12 millimeters.

[0299] The first element 11 also includes an elongated susceptor element 44 within the aerosol-forming substrate 12. More specifically, the susceptor element 44 is substantially longitudinally disposed within the aerosol-forming substrate 12, such as generally parallel to the longitudinal axis of the rod 11. As shown in the drawing in Figure 1, the susceptor element 44 is positioned at a radially central location within the rod and effectively extends along the longitudinal axis of the rod 11.

[0300] The susceptor element 44 extends all the way from the upstream end to the downstream end of the aerosol-forming substrate 12. In fact, the susceptor element 44 has substantially the same length as the first element 11 that comprises the aerosol-forming substrate 12.

[0301] In the embodiment of FIG. 1, the susceptor element 44 is provided in the form of a strip, having a length of about 12 millimeters, a thickness of about 60 micrometers, and a width of about 4 millimeters.

[0302] The upstream section 16 comprises an upstream element 46 located immediately upstream of the first element 11 and longitudinally aligned with the first element 11. In the embodiment of Figure 1, 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 the susceptor element 44 from becoming dislodged. Furthermore, this ensures that a consumer cannot accidentally come into contact with the heated susceptor element 44 after use.

[0303] The upstream element 46 is provided in the form of a cylindrical plug of cellulose acetate surrounded by a hard wrapper. The upstream element 46 has a length of approximately 5 millimeters. The RTD of the upstream element 46 is approximately 30 millimeters HO.

[0304] The tubular element 100 defines a cavity 106 that extends 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 of the tubular element 100. The end wall 104 defines a plurality of openings 110 for fluidly connecting the cavity 106 with the exterior of the tubular element 100. In particular, the embodiment of Figure 1 is configured such that an aerosol can flow from the first element 11 through the plurality of openings 110 and into the cavity 106.

[0305] The cavity 106 is substantially empty, thus allowing substantially unrestricted airflow along the cavity 106. As a result, the RTD of the tubular element 100 can be localized at a specific longitudinal location of the tubular element 100, i.e., the end wall 104, and can be controlled through a selected configuration of the end wall 104 and the plurality of openings 110. In the embodiment of FIG. 1, the RTD of the tubular element 100 (which is essentially the RTD of the end wall 104) is substantially 40 millimeters HO. In the embodiment of FIG. 1, the tubular element 100 has a length of approximately 16 millimeters, an outer diameter of approximately 7.25 millimeters, and an inner diameter of approximately 6.5 millimeters. Thus, the thickness of the peripheral wall (or tubular wall) of the tubular element 100 is approximately 0.75 millimeters.

[0306] As shown in FIG. 1 and explained in more detail in the perspective view of FIG. 2, the end wall 104 extends substantially transverse to the longitudinal axis of the aerosol-generating article 1 and the longitudinal axis of the tubular element 100. Each of the plurality of openings 110 has an equivalent diameter of about 1 millimeter. The plurality of openings 110 are substantially equally circumferentially spaced apart from the longitudinal axis of the tubular element 100 and substantially equally radially spaced apart. More specifically, in the embodiment of FIG. 1, the plurality of openings are equally circumferentially spaced apart by about 180 degrees and substantially equally radially spaced apart from the longitudinal axis of the tubular element 100 by about 1.5 millimeters. Thus, the plurality of openings are radially spaced apart from the longitudinal axis of the tubular element by about 21 percent of the end wall diameter.

[0307] The combination of the end wall 104 and the plurality of openings 110 provides an effective barrier arrangement that can limit movement of the aerosol-forming substrate 12 while allowing air and / or aerosol to flow from the first element 11 through the plurality of openings 110 into the cavity 106. The plurality of openings 110 are radially spaced from the longitudinal axis of the tubular element, which can be advantageous because it allows the air and aerosol flowing through the plurality of openings 110 to come into closer proximity with the peripheral wall of the tubular element 100.

[0308] 1, the aerosol-generating article 1 comprises multiple elements assembled in the form of a rod. The multiple elements include an upstream element 46, a first element 11, a tubular element 100, and a mouthpiece element 42. The multiple elements are surrounded by an outer wrapper 109. The outer wrapper 109 is made of paper.

[0309] Figures 3A-3E show a tubular element for an aerosol-generating article according to the invention through different stages in its formation, and thus illustrate a method of forming a tubular element such as tubular element 100 of Figure 1.

[0310] 3A, the method begins by providing a tubular element 300 having a first end 305 and a tubular body 303 adjacent and integral with the first end 305. A folding force is applied to the tubular element 300 to bend the first end portion 305 about a folding point 307 to form an end wall 104.

[0311] The folding force deflects the first end 305 inwardly, toward the cavity 306, relative to the tubular body 303 (as indicated by the dashed curved arrows in FIGS. 3A, 3B, and 3C). The folding force continues to be applied until the first end 305 is folded at an angle greater than 90 degrees, as measured relative to the wall of the tubular body 303. Such a position is shown in FIG. 3C. As can be seen in FIG. 3C, in such a position, at least a portion of the first end 105 of the tubular element extends into the cavity 306. Stated another way, at least a portion of the first end 305 of the tubular element has a longitudinal position that is between the position of the first end of the tubular body 303 and the position of the second end of the tubular body 303.

[0312] Once first end 305 reaches the position of Figure 3C, the folding force is no longer applied. At this point, the inherent elastic properties of the paper material (such as paper, paperboard, or corrugated board) of tubular element 300 cause first end 305 to partially return along its folding path such that it reaches a position where it extends substantially transverse to the longitudinal axis of tubular body 303. This position is shown in Figure 3D. Folding point 306 is selected so that folding first end 305 results in a closed-end tube, as shown in Figure 3D.

[0313] After forming the closed-end tube of Figure 3D, the end wall 304 is perforated to form a plurality of openings 110. This results in a tubular element 100 with an end wall 104 formed by the folded end of the tubular element 100, the end wall 104 defining a plurality of openings 110 for fluidly connecting the cavity 106 of the tubular element 100 with the exterior of the tubular element 100, as shown in Figure 3E.

[0314] In the arrangement of Figures 3A-3E, only one end of the tubular element 100 is folded, but it will be understood that similar method steps can be applied to the other end of the tubular element 100 to obtain a tubular element having two folded ends, each forming a first and second end wall for the tubular element.

[0315] 4 shows an end wall of a tubular element according to an embodiment of the invention having an alternative arrangement of openings. In this embodiment, end wall 404 includes a circular central region 430 that is coaxial with the longitudinal axis of the tubular element. For illustrative purposes, a perimeter 431 of circular central region 430 is shown with a dashed line. End wall 404 also includes a peripheral region 440 that surrounds central region 430. Peripheral region 440 is bounded by central region perimeter 431 and end wall 404 perimeter 441. Central region has a diameter that is approximately 62 percent of the diameter of end wall 404.

[0316] The central region 430 defines a substantially central opening 420. The substantially central opening 420 has an equivalent diameter of about 0.8. In other words, the equivalent diameter of the substantially central opening 420 is about 11 percent of the diameter of the end wall 404.

[0317] Peripheral region 440 defines a plurality of openings 410. The plurality of openings 410 are positioned substantially around the central opening and are substantially equally circumferentially spaced about 90 degrees apart. More specifically, each opening of the plurality of openings 410 has an equivalent diameter of about 1.1 millimeters. Thus, the total cross-sectional area of ​​the openings defined in peripheral region 440 is about 750 percent of the cross-sectional area of ​​the openings defined in central region 430.

[0318] 5 shows an end wall of a tubular element according to an embodiment of the invention having a further alternative arrangement of openings. In this embodiment, end wall 504 includes a circular central region 530 that is coaxial with the longitudinal axis of the tubular element. Again, for illustrative purposes, the periphery 531 of circular central region 530 is shown in dashed lines. End wall 504 also includes a peripheral region 540 that surrounds central region 530. The central region has a diameter that is approximately 70 percent of the diameter of end wall 504.

[0319] In the embodiment shown in Figure 5, circular central region 530 does not define any openings. In fact, circular central region 530 is impermeable. Peripheral region 540 defines a plurality of openings 510. The plurality of openings is rectangular and coincides with perimeter 541 of end wall 505. In this case, perimeter 541 of end wall 504 forms at least a portion of the perimeter of each of the plurality of openings. Each of the plurality of openings 510 has an equivalent diameter of approximately 0.7 millimeters.

[0320] FIG. 6 shows an aerosol-generating article 2 according to a second embodiment of the present invention. The aerosol-generating article 2 of the second embodiment is generally the same as the aerosol-generating article 1 of the first embodiment, except that the aerosol-generating article 2 of the second embodiment does not include any form of upstream element 46 upstream of the first element 11. Thus, the upstream 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, such an aerosol-generating article 2 may be configured to receive a heater blade of an aerosol-generating device. The heater blade may be inserted into the aerosol-forming substrate 12 through the upstream end 18 of the aerosol-generating article 2.

[0321] The tubular element 600 of the aerosol-generating article 2 of the second embodiment is substantially the same as the tubular element 100 of the aerosol-generating article 1 of the first embodiment, except that the tubular element 600 is longer than the tubular element 100.

[0322] FIG. 7 illustrates an aerosol-generating article 3 according to a third embodiment of the present invention. The aerosol-generating article 3 of the third embodiment is generally the same as the aerosol-generating article 2 of the second embodiment, and similar reference numerals are used where appropriate. However, the aerosol-generating article 3 of the third embodiment does not include a mouthpiece element 42 downstream of the tubular element 700. Instead, the tubular element 700 of FIG. 7 extends from the downstream end of the aerosol-forming substrate 12 all the way to the oral end 20 of the aerosol-generating article 3. Thus, the downstream section 14 of the aerosol-generating article 3 of FIG. 7 is formed entirely by the tubular element 700. Furthermore, in the embodiment of FIG. 7 , the end wall 704 of the tubular element 700 is not positioned adjacent to the downstream end of the aerosol-forming substrate 12. Instead, the end wall 704 of the tubular element 700 is positioned at the oral end 20 of the aerosol-generating article 3.

[0323] Figure 8 shows an aerosol-generating article 4 according to a fourth embodiment of the present invention. The aerosol-generating article 4 of the fourth embodiment is generally the same as the aerosol-generating article 3 of the third embodiment, and like reference numerals are used where appropriate. However, the aerosol-generating article 4 of the fifth embodiment includes a mouthpiece element in the form of a hollow tube 842 downstream of the tubular element 800. Thus, the tubular element 800 of Figure 8 extends all the way to the upstream end of this hollow tube 842. The downstream section 14 of the aerosol-generating article 6 of Figure 8 is therefore defined by the tubular element 800 and the hollow tube 842.

[0324] Figure 9 shows an aerosol-generating article 5 according to a fifth embodiment of the present invention. The aerosol-generating article 5 of the fifth embodiment is generally the same as the aerosol-generating article 1 of the first embodiment, and like reference numerals are used where appropriate.

[0325] However, in the embodiment of Figure 9, the tubular element 900 is not in contact with the first element 11, which contains the aerosol-forming substrate 12. Instead, an empty space 950 exists at the upstream end of the tubular element 900, between the downstream end of the first element 11 and the end wall 904. Thus, in the embodiment of Figure 9, the end wall 904 of the tubular element 900 does not provide a barrier in contact with the aerosol-forming substrate 12 to restrict movement of the aerosol-forming substrate 12. However, the empty space 950 does provide an area in which loose particles or debris from the aerosol-forming substrate 12 can collect during use of the aerosol-generating article 5. The end wall 904 may utilize gravity to prevent such loose particles or debris from moving further downstream within the aerosol-generating article 5.

[0326] For purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like are understood to be modified in all instances by the term "about." Also, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically recited herein. Thus, in this context, the number A is understood as A ± 5%. Within this context, the number A may be considered to include a numerical value that is within the typical standard error for measurement of the property that the number A modifies. In some cases, as used in the appended claims, the number A may deviate by the percentages recited above, provided that the amount by which A deviates does not materially affect the basic and novel characteristics of the claimed invention. Also, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically recited herein.

Claims

1. An aerosol-generating article comprising: a first element comprising an aerosol-forming substrate; a tubular element positioned downstream of the first element, the tubular element having an end wall formed by a folded end of the tubular element; The end wall defines a plurality of openings for fluidly connecting the interior of the tubular element with the exterior of the tubular element.

2. 2. The aerosol-generating article of claim 1, wherein the end wall is an upstream end wall.

3. 3. The aerosol-generating article of claim 1, wherein the plurality of openings are substantially equally circumferentially spaced apart.

4. 4. An aerosol-generating article according to any one of claims 1 to 3, wherein the plurality of openings are radially spaced apart from the longitudinal axis of the tubular element, preferably the plurality of openings are radially spaced apart from the longitudinal axis of the tubular element by at least 5 percent of the diameter of the end wall.

5. 5. The aerosol-generating article according to claim 1, wherein the plurality of openings coincide with the periphery of the end wall.

6. 6. An aerosol-generating article according to any one of claims 1 to 5, wherein the end walls further define a substantially central opening.

7. 7. The aerosol-generating article of claim 6, wherein the plurality of openings are positioned around the substantially central opening.

8. 8. An aerosol-generating article as described in claim 6 or 7, wherein the plurality of openings have a total cross-sectional area that is greater than the cross-sectional area of ​​the substantially central opening, and preferably the total cross-sectional area of ​​the plurality of openings is at least 200 percent of the cross-sectional area of ​​the substantially central opening.

9. the end wall includes a central region coaxial with a longitudinal axis of the tubular element, the end wall including a peripheral region surrounding the central region; the central region has a diameter that is 10 percent or greater than the diameter of the end wall; 9. An aerosol-generating article as described in any one of claims 1 to 8, wherein the total cross-sectional area of ​​the openings defined in the peripheral region of the end wall is greater than the total cross-sectional area of ​​any openings defined in the central region of the end wall.

10. 10. The aerosol-generating article of claim 9, wherein the total cross-sectional area of ​​the openings defined in the peripheral region is at least 60 percent of the total cross-sectional area of ​​all openings defined in the end wall.

11. 11. The aerosol-generating article of claim 9 or 10, wherein the plurality of openings are defined in the peripheral region.

12. An aerosol-generating article according to any preceding claim, wherein the tubular element defines a cavity extending from the upstream end of the tubular element to the downstream end of the tubular element, the cavity being preferably substantially empty.

13. 13. The aerosol-generating article of any preceding claim, further comprising ventilation zones at locations along the tubular element.

14. 14. The aerosol-generating article of claim 1, wherein the first element comprises a susceptor element arranged substantially longitudinally within the aerosol-forming substrate.

15. An electrically heated aerosol generating system comprising: the aerosol-generating article according to any one of claims 1 to 14; and an aerosol generating device comprising a heating element for heating the aerosol-forming substrate.

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