Aerosol-generating article with improved configuration

Abstract

To provide an aerosol-generating article for generating an inhalable aerosol upon heating.SOLUTION: An aerosol generating article (10) includes a rod (12) of aerosol generating substrate, a mouthpiece element (42) having a length of at least 10 millimetres, and an intermediate hollow section (50) between the rod (12) of aerosol generating substrate and the mouthpiece element (42). The intermediate hollow section (50) comprises an aerosol-cooling element (24) axially aligned with and abutting an upstream end of the mouthpiece element (42), the aerosol-cooling element (24) comprising a hollow tubular segment (34) having a length of less than 10 millimetres and defining a longitudinal cavity (36) providing an unrestricted flow channel, the hollow tubular segment having a wall thickness of between 1.5 millimetres and 2.5 millimetres.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an aerosol-generating article that includes an aerosol-generating substrate and is adapted to generate an inhalable aerosol upon heating. [Background technology]

[0002] Aerosol-generating articles in which an aerosol-generating substrate, such as a tobacco-containing substrate, is heated rather than combusted are known in the art. Typically, in such heated smoking articles, the aerosol is generated by transferring heat from a heat source to a physically separated aerosol-generating 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-generating substrate by heat transfer from the heat source and are entrained in the air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol.

[0003] Numerous prior art documents disclose aerosol generating devices for consuming aerosol-generating articles. These devices include, for example, electrically heated aerosol generating devices in which an aerosol is generated by heat transfer from one or more electric heater elements of the aerosol generating device to an aerosol-generating substrate of a heated aerosol-generating article. For example, an electrically heated aerosol generating device has been proposed that includes an internal heater blade adapted to be inserted into the aerosol-generating substrate. Alternatively, WO 2015 / 176898 proposes an inductively heated aerosol-generating article that includes an aerosol-generating substrate and a susceptor element disposed within the aerosol-generating substrate.

[0004] Aerosol-generating articles in which a tobacco-containing substrate is heated rather than combusted present several challenges not encountered by conventional smoking articles. First, the tobacco-containing substrate is typically heated to a significantly lower temperature compared to the temperature reached by the combustion front of a conventional cigarette. This can affect nicotine release from the tobacco-containing substrate and nicotine delivery to the consumer. At the same time, if the heating temperature is increased in an attempt to enhance nicotine delivery, the aerosol generated typically needs to be cooled more extensively and more quickly before reaching the consumer. However, technical solutions commonly used to cool mainstream smoke in conventional smoking articles, such as providing a high-filtration efficiency segment at the mouth end of the cigarette, can have undesirable effects in aerosol-generating articles in which the tobacco-containing substrate is heated rather than combusted, as this can reduce nicotine delivery. Second, there is a general need for aerosol-generating articles that are easier to use and have improved practicality in general.

[0005] It would therefore be desirable to provide a new and improved aerosol-generating article adapted to achieve at least one of the above-mentioned desired results. It would further be desirable to provide one such aerosol-generating article that can be manufactured efficiently and rapidly, and that preferably has a satisfactory RTD and low RTD variation between articles. Summary of the Invention

[0006] The present disclosure relates to an aerosol-generating article comprising a rod of aerosol-generating substrate. The aerosol-generating article may further comprise a mouthpiece element having a length of at least 10 millimeters. The aerosol-generating article may comprise an intermediate hollow section between the rod of aerosol-generating substrate and the mouthpiece element. The intermediate hollow section may comprise an aerosol cooling element axially aligned with the mouthpiece element and abutting the upstream end of the mouthpiece element. The aerosol cooling element may have a length of less than 10 millimeters. The aerosol cooling element may comprise a hollow tubular segment defining a longitudinal cavity that provides an unrestricted flow channel. The hollow tubular segment may have a wall thickness of less than 2.5 millimeters.

[0007] According to the present invention, there is provided an aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising a rod of aerosol-generating substrate, a mouthpiece element having a length of at least 10 millimeters, and an intermediate hollow section between the rod of aerosol-generating substrate and the mouthpiece element. The intermediate hollow section comprises an aerosol cooling element axially aligned with the mouthpiece element and abutting the upstream end of the mouthpiece element, the aerosol cooling element having a length of less than 10 millimeters and comprising a hollow tubular segment defining a longitudinal cavity providing an unrestricted flow channel. According to the present invention, the hollow tubular segment has a wall thickness of less than 2.5 millimeters.

[0008] The term "aerosol-generating article" is used herein to mean an article in which an aerosol-generating substrate is heated to generate an inhalable aerosol for delivery to a consumer. As used herein, the term "aerosol-generating substrate" means a substrate capable of generating an aerosol by releasing a volatile compound upon heating.

[0009] 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 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 a flavor-generating 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. For example, the aerosol-generating article according to the present invention finds particular application in aerosol-generating systems comprising an electrically heated aerosol generator having an internal heater blade adapted to be inserted into a rod of the aerosol-generating substrate. Aerosol-generating articles of this type are described in the prior art, for example, in EP 0 822 670.

[0010] As used herein, the term "aerosol-generating device" refers to a device that includes a heater element that interacts with an aerosol-generating substrate of an aerosol-generating article to generate an aerosol.

[0011] As used herein in connection with the present invention, the term "rod" is used to denote a generally cylindrical element of substantially circular, oval or elliptical cross section.

[0012] As used herein, the term "longitudinal" refers to a direction corresponding to a major longitudinal axis of the aerosol-generating article extending between the upstream and downstream ends of the aerosol-generating article. As used herein, the terms "upstream" and "downstream" describe the relative positions of elements (or portions of elements) of the aerosol-generating article with respect to the direction in which aerosol is transported through the aerosol-generating article during use.

[0013] In use, air is drawn longitudinally through the aerosol-generating article. The term "transverse" refers to a direction perpendicular to the longitudinal axis. Any reference to a "cross section" of an aerosol-generating article or a component of an aerosol-generating article refers to a transverse cross section, unless otherwise specified.

[0014] The term "length" refers to the dimension of a component of an aerosol-generating article in the longitudinal direction. For example, it may be used to refer to the dimension of a rod or elongated tubular element in the longitudinal direction.

[0015] As used herein, the term "hollow tubular segment" is used generally to mean an 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 understood that alternative shapes (e.g., alternative cross-sectional shapes) of the tubular segment may be possible. A hollow tubular segment is an individual, discrete element of an aerosol-generating article having a defined length and thickness.

[0016] 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.

[0017] In the context of the present invention, the hollow tubular segment provides an unrestricted flow channel. This means that the hollow tubular segment provides a negligible level of resistance to withdrawal (RTD). Therefore, the flow channel should not include any components that would obstruct the longitudinal air flow. Preferably, the flow channel is substantially empty.

[0018] The aerosol-generating article of the present invention provides an improved configuration of the downstream element of the aerosol-generating substrate rod, comprising a relatively long mouthpiece element having a length of at least 10 millimeters in combination with an aerosol-cooling element having a length of less than 10 millimeters, and formed from a hollow tubular segment having a relatively low wall thickness of less than 2.5 millimeters. This combination of elements has been found to achieve optimal aerosol delivery to the consumer during use. The aerosol-cooling element has a relatively large internal volume as a result of the low wall thickness of the hollow tubular segment, which achieves optimal cooling and nucleation of the aerosol.

[0019] Advantageously, the wall thickness of the hollow tubular segment can be selected at a level of less than 2.5 millimeters, which provides sufficient structural rigidity to prevent collapse of the aerosol cooling element during use while maintaining the benefits of improved cooling and nucleation, as described. Construction of the aerosol cooling element as a relatively thin-walled hollow tubular segment means that the aerosol cooling element has a minimal level of resistance to withdrawal (RTD) and therefore does not affect the overall RTD of the aerosol-generating article. Therefore, the overall RTD of the aerosol-generating article can be effectively tuned by adjusting the characteristics of the mouthpiece elements, such as length and density.

[0020] As described above, as a result of the optimized structure of the aerosol-cooling element, effective cooling and nucleation of the aerosol can be achieved over a relatively short distance, such that the length of the aerosol-cooling element can be reduced compared to prior art articles. This, in turn, allows the length of the mouthpiece element to be increased while maintaining the same overall length of the aerosol-generating article. As explained in more detail below, the inclusion of a relatively long mouthpiece provides optimal filtration of the aerosol.

[0021] Furthermore, it has been found that this combination of elements in an aerosol-generating article according to the present invention advantageously provides improved tactile feedback to the consumer during use. The hollow tubular segment of the aerosol cooling element provides a relatively high degree of rigidity compared to the mouthpiece, thus allowing the consumer to more clearly feel the junction between the mouthpiece and the aerosol cooling element. This allows the consumer to position their lips in the appropriate position on the aerosol-generating article, minimizing the risk of blocking the provided ventilation holes.

[0022] The combination of a relatively long mouthpiece element with an aerosol cooling element in the form of a hollow tubular segment has also been found to advantageously provide a more rigid mouthpiece element in an aerosol-generating article according to the present invention. Accordingly, the aerosol-generating article can provide greater resistance to radial compression toward the downstream end of the article. Advantageously, this benefit can be provided without affecting the overall length of the article, so as to maintain an overall length consistent with existing aerosol-generating articles.

[0023] It has been found that providing a more rigid mouthpiece element contributes to a more efficient puffing action by the consumer, so that aerosol delivery can be further optimized. Furthermore, by providing a more rigid mouthpiece element proximal to the aerosol cooling element, the risk of deformation of the aerosol cooling element during use can be significantly reduced. This is important because deformation of the aerosol cooling element is undesirable due to the adverse effects such deformation can have on aerosol formation.

[0024] The mouthpiece element is typically more resilient to deformation than other elements provided downstream of the rod of the aerosol-generating substrate. Therefore, increasing the length of the mouthpiece element relative to the length of the intermediate hollow section has been found to provide an improved grip by the consumer. Insertion of the aerosol-generating article into the heating device is also facilitated.

[0025] Increasing the length of the mouthpiece element provides several other technical advantages. Longer mouthpiece elements can be used to provide greater filtration and removal of undesirable aerosol components, such as phenol, thereby delivering a higher quality aerosol. Furthermore, the use of longer mouthpiece elements allows for more complex mouthpiece structures to be provided, as there is more space to incorporate mouthpiece components such as capsules, threads, and restrictors.

[0026] As described, the relatively long mouthpiece element of the aerosol-generating article according to the present invention can be particularly effective when combined with an intermediate hollow section having a reduced length. A reduction in the length of the hollow intermediate section relative to the mouthpiece element can be advantageously provided by reducing the length of the aerosol cooling element, as described in more detail below. Aerosol cooling elements typically have a lower resistance to deformation than the mouthpiece element. Reducing the length of the aerosol cooling element further reduces the risk of deformation of the aerosol-generating article due to compression during use. Furthermore, reducing the length of the aerosol cooling element can provide cost benefits to manufacturers, as the cost of hollow tubular segments is typically higher per unit length than the cost of the mouthpiece element.

[0027] According to the present invention, there is provided an aerosol-generating article for generating an inhalable aerosol upon heating. The aerosol-generating article comprises a rod of aerosol-generating substrate. The aerosol-generating article further comprises a downstream section located downstream of the rod of aerosol-generating substrate. The downstream section may comprise one or more downstream elements.

[0028] In an aerosol-generating article according to the present invention, the downstream section comprises a mouthpiece element. The mouthpiece element may extend all the way to the oral end of the aerosol-generating article. The downstream section further comprises an intermediate hollow section between the mouthpiece element and the rod of the aerosol-generating substrate. The intermediate hollow section comprises an aerosol cooling element. The aerosol cooling element comprises a hollow tubular segment. The intermediate hollow section may further comprise a support element, which may comprise a hollow tubular segment.

[0029] In some embodiments, the aerosol-generating article may include a ventilation zone at a location along the downstream section. More particularly, the aerosol-generating article may include a ventilation zone at a location along the aerosol cooling element. In a preferred embodiment, the aerosol cooling element includes or is in the form of a hollow tubular segment, and the ventilation zone is provided at a location along the hollow tubular segment of the aerosol cooling element.

[0030] The aerosol-generating article may further comprise an upstream section located upstream of the rod of aerosol-generating substrate. The upstream section may comprise one or more upstream elements. In some embodiments, the upstream section comprises an upstream element located immediately upstream of the rod of aerosol-generating substrate.

[0031] The aerosol-generating article may further comprise a susceptor element within the aerosol-generating substrate. In some embodiments, the susceptor element may be an elongated susceptor element. In a preferred embodiment, the susceptor element extends longitudinally within the aerosol-generating substrate.

[0032] These elements of the aerosol-generating article are described in more detail below.

[0033] As defined above, the downstream section of the aerosol-generating article of the present invention comprises a mouthpiece element. The mouthpiece element is preferably located at the downstream or mouth end of the aerosol-generating article. The mouthpiece element preferably comprises at least one mouthpiece filter segment for filtering the aerosol generated from the aerosol-generating 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. Particularly preferably, the at least one mouthpiece filter segment comprises a cellulose acetate filter segment formed from cellulose acetate tow.

[0034] In certain preferred embodiments, the mouthpiece element comprises a single mouthpiece filter segment, hi alternative embodiments, the mouthpiece element comprises two or more mouthpiece filter segments axially aligned in end-to-end relationship with one another.

[0035] In certain embodiments of the present invention, the downstream section may comprise a mouth-end cavity at a downstream end downstream of the mouthpiece element as described above. 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 an outer wrapper of the mouthpiece element, where the outer wrapper extends in a downstream direction from the mouthpiece element.

[0036] The mouthpiece element may optionally include a flavorant, which may be provided in any suitable form, for example, the mouthpiece element may include one or more capsules, flavorant beads or granules, or one or more flavor-loaded threads or filaments.

[0037] In aerosol-generating articles according to the invention, the mouthpiece element forms part of the downstream section and is therefore located downstream of the rod of the aerosol-generating substrate.

[0038] Preferably, the mouthpiece element is located immediately downstream of the aerosol cooling element. As an example, the mouthpiece element may abut the downstream end of the aerosol cooling element.

[0039] Preferably, the mouthpiece element has a low particle filtration efficiency.

[0040] Preferably, the mouthpiece is formed from a segment of fibrous filtering material.

[0041] 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 along the mouthpiece element.

[0042] The mouthpiece element is preferably connected to one or more of the adjacent upstream components of the aerosol-generating article by a tip wrapper.

[0043] 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.

[0044] 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.

[0045] The mouthpiece element preferably has 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.

[0046] In accordance with the present invention, the mouthpiece element preferably has a length of at least about 10 millimeters, more preferably at least about 11 millimeters, more preferably at least about 12 millimeters. Alternatively, or additionally, the mouthpiece element preferably has a length of less than about 25 millimeters, more preferably less than about 20 millimeters, more preferably less than about 15 millimeters.

[0047] In some embodiments, the mouthpiece element preferably has 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. In other embodiments, the mouthpiece element preferably has 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 20 millimeters. In other embodiments, the mouthpiece element preferably has 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.

[0048] In a preferred embodiment, the mouthpiece element has a length of approximately 12 millimeters.

[0049] In the aerosol-generating articles of the present invention, the mouthpiece element is relatively long compared to mouthpiece elements provided in prior art articles. The provision of a relatively long mouthpiece element in the aerosol-generating articles of the present invention may provide several benefits to the consumer, as discussed above.

[0050] In a particularly preferred embodiment of the present invention, a mouthpiece element having a length of at least 10 millimeters is combined with a relatively short aerosol cooling element, for example, an aerosol cooling element having a length of less than 10 millimeters. This combination has been found to reduce the risk of deformation of the aerosol cooling element during use and to provide a more rigid mouthpiece element that contributes to a more efficient puffing action by the consumer.

[0051] The length of the mouthpiece element is preferably at least 0.4 times the total length of the intermediate hollow section, preferably at least 0.5 times the length of the intermediate hollow section, more preferably at least 0.6 times the length of the intermediate hollow section, more preferably at least 0.7 times the length of the intermediate hollow section. Thus, the ratio between the length of the mouthpiece element and the total length of the intermediate hollow section is at least about 0.4, preferably at least about 0.5, more preferably at least about 0.6, and most preferably at least about 0.7.

[0052] The ratio between the length of the mouthpiece element and the length of the rod of the aerosol-generating substrate may be from about 0.5 to about 1.5.

[0053] The ratio between the length of the mouthpiece element and the length of the rod of the aerosol-generating substrate is preferably at least about 0.6, more preferably at least about 0.7, and even more preferably at least about 0.8. In preferred embodiments, the ratio between the length of the mouthpiece element and the length of the rod of the aerosol-generating substrate is less than about 1.4, more preferably less than about 1.3, and even more preferably less than about 1.2.

[0054] In some embodiments, the ratio between the length of the mouthpiece element and the length of the rod of the aerosol-generating substrate is about 0.6 to about 1.4, preferably about 0.7 to about 1.4, and more preferably about 0.8 to about 1.4. In other embodiments, the ratio between the length of the mouthpiece element and the length of the rod of the aerosol-generating substrate is about 0.6 to about 1.3, preferably about 0.7 to about 1.3, and more preferably about 0.8 to about 1.3. In further embodiments, the ratio between the length of the mouthpiece element and the length of the rod of the aerosol-generating substrate is about 0.6 to about 1.2, preferably about 0.7 to about 1.2, and more preferably about 0.8 to about 1.2.

[0055] In a particularly preferred embodiment, the ratio between the length of the mouthpiece element and the length of the rod of the aerosol-generating substrate is about 1.

[0056] The ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article substrate may be from about 0.2 to about 0.35.

[0057] Preferably, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article substrate is at least about 0.22, more preferably at least about 0.24, and even more preferably at least about 0.26. The ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article substrate is preferably less than about 0.34, more preferably less than about 0.32, and even more preferably less than about 0.3.

[0058] In some embodiments, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article substrate is preferably 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. In other embodiments, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article substrate is preferably 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 further embodiments, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article substrate 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.

[0059] In a particularly preferred embodiment, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article substrate is about 0.27.

[0060] As mentioned above, the downstream section of the aerosol-generating article according to the present invention further comprises an intermediate hollow section comprising an aerosol-cooling element aligned with and positioned downstream of the rod of the aerosol-generating substrate.

[0061] The aerosol cooling element is positioned substantially in alignment with the rod, meaning that the length dimension of the aerosol cooling element is positioned approximately parallel to the longitudinal direction of the rod and article, for example, within ±10 degrees of parallel to the longitudinal direction of the rod. In a preferred embodiment, the aerosol cooling element extends along the longitudinal axis of the rod.

[0062] In an aerosol-generating article according to the invention, the aerosol cooling element is in the form of a hollow tubular segment defining a cavity extending entirely from the upstream end of the aerosol cooling element to the downstream end of the aerosol cooling element, and preferably, ventilation zones are provided at locations along the hollow tubular segment.

[0063] The inventors have found that satisfactory cooling of the aerosol stream generated upon heating of an aerosol-generating substrate and drawn through one of such aerosol-cooling elements can be achieved by providing ventilation zones at locations along the hollow tubular segment. Furthermore, the inventors have found that, as described in more detail below, it may be possible to counter the effects of increased aerosol dilution caused by entrainment of ventilation air into the article, particularly by locating ventilation zones at precisely defined locations along the length of the aerosol-cooling element, and preferably by utilizing hollow tubular segments having a predetermined wall thickness or internal volume.

[0064] Without being bound by theory, it is believed that the introduction of ventilated air rapidly reduces the temperature of the aerosol stream as it moves toward the mouthpiece segment, so that the ventilated air enters the aerosol stream relatively close to the upstream end of the aerosol-cooling element (i.e., close enough to the susceptor element extending into the rod of the aerosol-generating substrate that is the heat source in use), achieving dramatic cooling of the aerosol stream, which has a favorable effect on aerosol particle condensation and nucleation. As a result, the overall ratio of aerosol particle phase to aerosol vapor phase may be increased compared to existing non-vented aerosol-generating articles.

[0065] At the same time, maintaining a relatively low peripheral wall thickness of the hollow tubular segment ensures that the overall internal volume of the hollow tubular segment, which becomes available for the aerosol to initiate the nucleation process as soon as the aerosol components leave the aerosol-generating substrate rod, and the cross-sectional area of ​​the hollow tubular segment are effectively maximized, while simultaneously ensuring that the hollow tubular segment has the structural strength necessary to prevent collapse of the aerosol-generating article and provide some support to the aerosol-generating substrate rod, and that the RTD of the hollow tubular segment is minimized. It is understood that a larger value for the cross-sectional area of ​​the cavity of the hollow tubular segment is associated with a reduced velocity of the aerosol stream traveling along the aerosol-generating article, which is expected to further favor nucleation. Furthermore, it is understood that utilizing hollow tubular segments with a relatively low thickness can substantially prevent the diffusion of the vent air before it contacts and mixes with the aerosol stream, further favoring the nucleation phenomenon. In effect, by providing more controllably localized cooling of the stream of volatilized species, it is possible to improve the cooling effect on the formation of new aerosol particles.

[0066] The aerosol cooling element preferably has an outer diameter approximately equal to the outer diameter of the rod of the aerosol-generating substrate and the outer diameter of the aerosol-generating article.

[0067] The aerosol cooling element may have an outer diameter of 5 millimeters to 12 millimeters, such as an outer diameter of 5 millimeters to 10 millimeters, or an outer diameter of 6 millimeters to 8 millimeters. In a preferred embodiment, the aerosol cooling element has an outer diameter of 7.2 millimeters plus or minus 10 percent.

[0068] Preferably, the hollow tubular segment of the aerosol cooling element has an inner diameter of at least about 2 millimeters. More preferably, the hollow tubular segment of the aerosol cooling element has an inner diameter of at least about 2.5 millimeters. Even more preferably, the hollow tubular segment of the aerosol cooling element has an inner diameter of at least about 3 millimeters.

[0069] In accordance with the present invention, the hollow tubular segments of the aerosol cooling element have a wall thickness of less than about 2.5 millimeters, preferably less than about 2.2 millimeters. In a preferred embodiment, the hollow tubular segments of the aerosol cooling element have a wall thickness of about 2 millimeters.

[0070] The hollow tubular segments of the aerosol cooling element preferably have a wall thickness of at least about 1.5 millimeters, more preferably at least about 1.75 millimeters, and therefore preferably have a wall thickness of from about 1.5 millimeters to about 2.5 millimeters, or from about 1.75 millimeters to about 2.5 millimeters, or from about 1.75 millimeters to about 2.2 millimeters, or approximately 2 millimeters.

[0071] Preferably, the aerosol cooling element has a length of at least about 5 millimeters, more preferably at least about 6 millimeters, more preferably at least about 7 millimeters.

[0072] In accordance with the present invention, the aerosol cooling element has a length of less than about 10 millimeters, preferably less than about 9 millimeters.

[0073] In some embodiments, the aerosol cooling element has a length of about 5 millimeters to about 10 millimeters, preferably about 6 millimeters to about 10 millimeters, and more preferably about 7 millimeters to about 10 millimeters. In other embodiments, the aerosol cooling element has a length of about 5 millimeters to about 9 millimeters, preferably about 6 millimeters to about 9 millimeters, and more preferably about 7 millimeters to about 9 millimeters. For example, in one particularly preferred embodiment, the aerosol cooling element has a length of 8 millimeters.

[0074] In the aerosol-generating article according to the present invention, the aerosol cooling element therefore has a relatively short length compared to the aerosol cooling elements of prior art aerosol-generating articles. The reduction in the length of the aerosol cooling element is possible due to the optimization of the effectiveness of the hollow tubular segments forming the aerosol cooling element in aerosol cooling and nucleation. The reduction in the length of the aerosol cooling element advantageously reduces the risk of deformation of the aerosol-generating article due to compression during use, since the aerosol cooling element typically has lower resistance to deformation than the mouthpiece. Furthermore, the reduction in the length of the aerosol cooling element can provide cost benefits to manufacturers, since the cost of hollow tubular segments is typically higher per unit length than the cost of other elements, such as the mouthpiece element.

[0075] The ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-generating substrate may be from about 0.25 to about 1.

[0076] Preferably, the ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-generating substrate is at least about 0.3, more preferably at least about 0.4, even more preferably at least about 0.5. In preferred embodiments, the ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-generating substrate is less than about 0.9, more preferably less than about 0.8, even more preferably less than about 0.7.

[0077] In some embodiments, the ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-generating substrate is about 0.3 to about 0.9, preferably about 0.4 to about 0.9, and more preferably about 0.5 to about 0.9. In other embodiments, the ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-generating substrate is about 0.3 to about 0.8, preferably about 0.4 to about 0.8, and more preferably about 0.5 to about 0.8. In further embodiments, the ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-generating substrate is about 0.3 to about 0.7, preferably about 0.4 to about 0.7, and more preferably about 0.5 to about 0.7.

[0078] In a particularly preferred embodiment, the ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-generating substrate is about 0.66.

[0079] Preferably, the ratio between the length of the aerosol-cooling element and the total length of the aerosol-generating article substrate is at least about 0.13, more preferably at least about 0.14, and even more preferably at least about 0.15. The ratio between the length of the aerosol-cooling element and the total length of the aerosol-generating article substrate is preferably less than about 0.3, more preferably less than about 0.25, and even more preferably less than about 0.20.

[0080] In some embodiments, the ratio between the length of the aerosol-cooling element and the overall length of the aerosol-generating article substrate is preferably about 0.13 to about 0.3, more preferably about 0.14 to about 0.3, and even more preferably about 0.15 to about 0.3. In other embodiments, the ratio between the length of the aerosol-cooling element and the overall length of the aerosol-generating article substrate is preferably about 0.13 to about 0.25, more preferably about 0.14 to about 0.25, and even more preferably about 0.15 to about 0.25. In further embodiments, the ratio between the length of the aerosol-cooling element and the overall length of the aerosol-generating article substrate is preferably about 0.13 to about 0.2, more preferably about 0.14 to about 0.2, and even more preferably about 0.15 to about 0.2.

[0081] In a particularly preferred embodiment, the ratio between the length of the aerosol-cooling element and the overall length of the aerosol-generating article substrate is about 0.18.

[0082] The length of the mouthpiece element is preferably at least 1 millimeter greater than the length of the aerosol cooling element, more preferably at least 2 millimeters greater than the length of the aerosol cooling element, and more preferably at least 3 millimeters greater than the length of the aerosol cooling element. Reducing the length of the aerosol cooling element as described above can advantageously allow for an increase in the length of other elements of the aerosol-generating article, such as the mouthpiece element. The potential technical benefits of providing a relatively long mouthpiece element are discussed above.

[0083] The ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-generating substrate may be from about 0.25 to about 1.

[0084] Preferably, the ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-generating substrate is at least about 0.3, more preferably at least about 0.4, even more preferably at least about 0.5. In preferred embodiments, the ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-generating substrate is less than about 0.9, more preferably less than about 0.8, even more preferably less than about 0.7.

[0085] In some embodiments, the ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-generating substrate is about 0.3 to about 0.9, preferably about 0.4 to about 0.9, and more preferably about 0.5 to about 0.9. In other embodiments, the ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-generating substrate is about 0.3 to about 0.8, preferably about 0.4 to about 0.8, and more preferably about 0.5 to about 0.8. In further embodiments, the ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-generating substrate is about 0.3 to about 0.7, preferably about 0.4 to about 0.7, and more preferably about 0.5 to about 0.7.

[0086] In a particularly preferred embodiment, the ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-generating substrate is about 0.66.

[0087] The ratio between the length of the aerosol-cooling element and the overall length of the aerosol-generating article substrate may be from about 0.125 to about 0.375.

[0088] Preferably, the ratio between the length of the aerosol-cooling element and the total length of the aerosol-generating article substrate is at least about 0.13, more preferably at least about 0.14, and even more preferably at least about 0.15. The ratio between the length of the aerosol-cooling element and the total length of the aerosol-generating article substrate is preferably less than about 0.3, more preferably less than about 0.25, and even more preferably less than about 0.20.

[0089] In some embodiments, the ratio between the length of the aerosol-cooling element and the overall length of the aerosol-generating article substrate is preferably about 0.13 to about 0.3, more preferably about 0.14 to about 0.3, and even more preferably about 0.15 to about 0.3. In other embodiments, the ratio between the length of the aerosol-cooling element and the overall length of the aerosol-generating article substrate is preferably about 0.13 to about 0.25, more preferably about 0.14 to about 0.25, and even more preferably about 0.15 to about 0.25. In further embodiments, the ratio between the length of the aerosol-cooling element and the overall length of the aerosol-generating article substrate is preferably about 0.13 to about 0.2, more preferably about 0.14 to about 0.2, and even more preferably about 0.15 to about 0.2.

[0090] In a particularly preferred embodiment, the ratio between the length of the aerosol-cooling element and the overall length of the aerosol-generating article substrate is about 0.18.

[0091] The length of the mouthpiece element is preferably at least 1 millimeter greater than the length of the aerosol cooling element, more preferably at least 2 millimeters greater than the length of the aerosol cooling element, and more preferably at least 3 millimeters greater than the length of the aerosol cooling element. Reducing the length of the aerosol cooling element as described above can advantageously allow for an increase in the length of other elements of the aerosol-generating article, such as the mouthpiece element. The potential technical benefits of providing a relatively long mouthpiece element are discussed above.

[0092] In aerosol-generating articles according to the present invention, the aerosol cooling element preferably has an average radial hardness of at least about 80 percent, more preferably at least about 85 percent, and even more preferably at least about 90 percent, such that the aerosol cooling element can provide the aerosol-generating article with the desired level of hardness.

[0093] If desired, the radial stiffness of the aerosol cooling element of an aerosol-generating article according to the present invention may be further increased by surrounding the aerosol cooling element with a stiff plug wrap, such as a plug wrap having a basis weight of at least about 80 grams per square meter (gsm), or at least about 100 gsm, or at least about 110 gsm.

[0094] As used herein, the term "radial hardness" of an element refers to its resistance to compression in a direction transverse to the longitudinal axis of the element. The radial hardness of an aerosol-generating article around an element can be determined by applying a load across the article at the location of the element in a direction transverse to the longitudinal axis of the article and measuring the average (mean) depressed diameter of the article. Radial hardness is given by: TIFF2026034549000002.tif2061D S is the original (undepressed) diameter, and D dis the depressed diameter after applying a set load for a set duration. The harder the material, the closer the hardness will be to 100 percent.

[0095] To determine the hardness of a portion of an aerosol article (such as an aerosol cooling element provided in the form of a hollow tubing segment), the aerosol-generating articles should be aligned parallel in a plane, and the same portion of each aerosol-generating article being tested should be subjected to a set load for a set duration. This test is performed using a known DD60A Densimeter instrument (manufactured and sold by Heinr Borgwaldt GmbH, Germany), which is fitted with a measuring head for an aerosol-generating article such as a cigarette, and which also includes an aerosol-generating article container.

[0096] Load is applied using two load-applying cylindrical rods that extend across the diameter of all aerosol-generating articles at once. According to the standard test method for this instrument, the test should be conducted so that twenty points of contact occur between the aerosol-generating articles and the load-applying cylindrical rods. In some cases, the hollow tube segment being tested may be long enough so that only ten aerosol-generating articles are needed to form twenty points of contact where each smoking article contacts both load-applying rods (because they are long enough to extend between both rods). In other cases, if the support element is too short to achieve this, twenty aerosol-generating articles should be used to form twenty points of contact, with each aerosol-generating article contacting only one of the load-applying rods, as discussed further below.

[0097] Two additional fixed cylindrical rods are positioned below the aerosol-generating article to support the aerosol-generating article and counter the loads exerted by each of the load-applying cylindrical rods.

[0098] For standard operating procedures for such devices, a total load of 2 kg is applied for 20 seconds. After 20 seconds have elapsed (and the load is still applied to the smoking article), the depression on the load-applying cylindrical rod is determined and then used to calculate hardness from the above equation. The temperature is maintained within a range of 22 degrees Celsius ± 2 degrees Celsius. The above test is referred to as the DD60A test. The standard method for measuring filter hardness is when the aerosol-generating article has not yet been consumed. Additional information regarding measuring average radial hardness can be found, for example, in U.S. Published Patent Application Publication No. 2016 / 0128378.

[0099] The aerosol cooling element may be formed from any suitable material or combination of materials. For example, the aerosol cooling element may be formed from one or more materials selected from the group consisting of cellulose acetate, cardboard, crimped paper (such as crimped heat-resistant paper or crimped parchment paper), and polymeric materials (such as low-density polyethylene (LDPE)). Other suitable materials include polyhydroxyalkanoate (PHA) fibers.

[0100] In a preferred embodiment, the aerosol cooling element is formed from cellulose acetate.

[0101] Preferably, the hollow tubular segment of the aerosol cooling element is adapted to generate an RTD of approximately 0 millimeters of HO (about 0 Pa) to approximately 20 millimeters of HO (about 100 Pa), more preferably approximately 0 millimeters of HO (about 0 Pa) to approximately 10 millimeters of HO (about 100 Pa).

[0102] In an aerosol-generating article according to the present invention, the overall RTD of the article depends essentially on the RTD of the rod and, optionally, the RTD of the mouthpiece and / or upstream plug, since the hollow tubular segments of the aerosol-cooling element and the hollow tubular segments of the support element are substantially empty and therefore only make a substantially small contribution to the overall RTD of the aerosol-generating article.

[0103] The ventilation zone comprises a plurality of perforations through the peripheral wall of the aerosol-cooling element. Preferably, the ventilation zone comprises at least one peripheral row of perforations. In some embodiments, the ventilation zone may comprise two peripheral rows of perforations. For example, the perforations may be formed online during the manufacture of the aerosol-generating article. Preferably, each peripheral row of perforations comprises between 8 and 30 perforations.

[0104] Aerosol-generating articles according to the present invention may have a breathability level of at least about 5 percent.

[0105] 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.

[0106] Aerosol-generating articles may typically have a breathability level of at least about 10 percent, preferably at least about 15 percent, and even more preferably at least about 20 percent.

[0107] In a preferred embodiment, 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. Preferably, the aerosol-generating article according to the present invention has a breathability level of about 45 percent or less. More preferably, the aerosol-generating article according to the present invention has a breathability level of about 40 percent or less, and even more preferably about 35 percent or less.

[0108] In particularly preferred embodiments, the aerosol-generating article has a ventilation level of about 30 percent. In some embodiments, the aerosol-generating article has 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. In other embodiments, the aerosol-generating article has 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.

[0109] In particularly 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.

[0110] Without wishing to be bound by theory, the inventors have found that the temperature reduction caused by admitting cooler outside air into the hollow tubular segment through the ventilation zone can have a beneficial effect on the nucleation and growth of aerosol particles.

[0111] 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.

[0112] 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.

[0113] Thus, the rapid cooling induced by admitting ambient air into the hollow tubular segment through 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 hollow tubular segment has the direct drawback of diluting the aerosol stream delivered to the consumer.

[0114] The inventors have surprisingly found that the dilution effect on the aerosol (which may be assessed, inter alia, by measuring the effect on the delivery of the aerosol former (e.g., glycerol) contained in the aerosol-generating 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.

[0115] The inventors have surprisingly found that the favorable effect 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, and therefore satisfactory aerosol delivery values ​​are consistently achieved by aerosol-generating articles in accordance with the present invention.

[0116] This is particularly advantageous for "short" aerosol-generating articles, such as a rod of aerosol-generating substrate less than about 40 millimeters in length, preferably less than 25 millimeters, and even more preferably less than 20 millimeters, or a total length of the aerosol-generating article 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.

[0117] Furthermore, because the vented hollow tubular segment does not substantially contribute to the overall RTD of the aerosol-generating article, the overall RTD of the article can be advantageously fine-tuned in an aerosol-generating article according to the present invention by adjusting the length and density of the rod of the aerosol-generating substrate, or the length and optional length and density of the segment of filtering material forming part of the mouthpiece, or the length and density of the segment of filtering material provided upstream of the aerosol-generating substrate and susceptor element. This therefore makes it possible to consistently and very accurately manufacture aerosol-generating articles having a predetermined RTD so as to provide consumers with a satisfactory level of RTD, even in the presence of ventilation.

[0118] In some embodiments, the aerosol-generating article may further comprise an additional cooling element defining multiple longitudinally extending channels, such as to make a high surface area available for heat exchange. In other words, one such additional cooling element is adapted to function substantially as a heat exchanger. The multiple longitudinally extending channels may be defined by a sheet material that has been pleated, gathered, or folded to form the channels. The multiple longitudinally extending channels may be defined by a single sheet that has been pleated, gathered, or folded to form the multiple channels. The sheet may also be crimped before being pleated, gathered, or folded. Alternatively, the multiple longitudinally extending channels may be defined by multiple sheets that have been crimped, pleated, gathered, or folded to form the multiple channels. In some embodiments, the multiple longitudinally extending channels may be defined by multiple sheets that have been crimped, pleated, gathered, or folded, i.e., two or more sheets that have been brought into an overlay arrangement and then crimped, pleated, gathered, or folded as one. As used herein, the term "sheet" means a laminar element having a width and length that is substantially greater than its thickness.

[0119] As used herein, the term "longitudinal" refers to a direction extending along or parallel to the cylindrical axis of the rod. As used herein, the term "crimped" refers to a sheet having a plurality of substantially parallel ridges or corrugations. When the aerosol-generating article is assembled, the substantially parallel ridges or corrugations preferably extend longitudinally relative to the rod. As used herein, the terms "gathered," "pleated," or "folded" mean that a sheet of material is convoluted, folded, or otherwise compressed or contracted in a direction substantially transverse to the cylindrical axis of the rod. The sheet may be crimped before being gathered, pleated, or folded. The sheet may also be gathered, pleated, or folded without prior crimping.

[0120] One such additional cooling element may have a total surface area of ​​about 300 square millimeters per millimeter of length to about 1000 square millimeters per millimeter of length.

[0121] Preferably, the additional cooling element provides a low resistance to air passage through the additional cooling element. Preferably, the additional cooling element does not substantially affect the resistance to air passage through the aerosol-generating article. To achieve this, the longitudinal porosity is preferably greater than 50 percent, and the airflow path through the additional cooling element is preferably relatively unrestricted. The longitudinal porosity of the additional cooling element may be defined by the ratio of the cross-sectional area of ​​the material forming the additional cooling element to the internal cross-sectional area of ​​the aerosol-generating article at the location of the portion including the additional cooling element.

[0122] The additional cooling element preferably comprises a sheet material selected from the group including metal foil, polymeric sheet, and substantially imperforate paper or cardboard. In some embodiments, the aerosol cooling element may comprise a sheet material selected from the group consisting of polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polylactic acid (PLA), cellulose acetate (CA), and aluminum foil. In a particularly preferred embodiment, the additional cooling element comprises a sheet of PLA.

[0123] As mentioned above, the intermediate hollow section preferably further comprises a support element aligned with and positioned downstream of the rod of the aerosol-generating substrate. In particular, the support element may be located immediately downstream of the rod of the aerosol-generating substrate, or adjacent to the rod of the aerosol-generating substrate.

[0124] The support element may be formed from any suitable material or combination of materials. For example, the support element may be formed from one or more materials selected from the group consisting of cellulose acetate, cardboard, crimped paper (such as crimped heat-resistant paper or crimped parchment paper), and polymeric materials (such as low-density polyethylene (LDPE)). In a preferred embodiment, the support element is formed from cellulose acetate. Other suitable materials include polyhydroxyalkanoate (PHA) fibers.

[0125] The support element may comprise a hollow tubular segment. In a preferred embodiment, the support element comprises a hollow cellulose acetate tube.

[0126] The support element is preferably positioned substantially aligned with the rod, meaning that the length dimension of the support element is positioned approximately parallel to the longitudinal direction of the rod and article, for example, within ±10 degrees of parallel to the longitudinal direction of the rod. In a preferred embodiment, the support element extends along the longitudinal axis of the rod.

[0127] The support element preferably has an outer diameter approximately equal to the outer diameter of the rod of the aerosol-generating substrate and the outer diameter of the aerosol-generating article.

[0128] The support element may have an outer diameter of 5 millimeters to 12 millimeters, such as an outer diameter of 5 millimeters to 10 millimeters, or an outer diameter of 6 millimeters to 8 millimeters. In a preferred embodiment, the support element has an outer diameter of 7.2 millimeters ± 10 percent.

[0129] The peripheral wall of the support element may have a thickness of at least 1 millimeter, preferably at least about 1.5 millimeters, and more preferably at least about 2 millimeters.

[0130] The support element may have a length of from about 5 millimeters to about 15 millimeters.

[0131] Preferably, the support element has a length of at least about 6 millimeters, and more preferably at least about 7 millimeters.

[0132] In preferred embodiments, the support element has a length of less than about 12 millimeters, more preferably less than about 10 millimeters.

[0133] In some embodiments, the support element has a length of about 5 millimeters to about 15 millimeters, preferably about 6 millimeters to about 15 millimeters, and more preferably about 7 millimeters to about 15 millimeters. In other embodiments, the support element has a length of about 5 millimeters to about 12 millimeters, preferably about 6 millimeters to about 12 millimeters, and more preferably about 7 millimeters to about 12 millimeters. In further embodiments, the support element has a length of about 5 millimeters to about 10 millimeters, preferably about 6 millimeters to about 10 millimeters, and more preferably about 7 millimeters to about 10 millimeters.

[0134] In a preferred embodiment, the support element has a length of about 8 millimeters.

[0135] Preferably, the intermediate hollow section has an overall length of about 18 millimeters or less, preferably about 17 millimeters or less, and more preferably about 16 millimeters or less.

[0136] The ratio between the length of the support element and the length of the rod of the aerosol-generating substrate may be from about 0.25 to about 1.

[0137] The ratio between the length of the support element and the length of the rod of the aerosol-generating substrate is at least about 0.3, more preferably at least about 0.4, and even more preferably at least about 0.5. In preferred embodiments, the ratio between the length of the support element and the length of the rod of the aerosol-generating substrate is less than about 0.9, more preferably less than about 0.8, and even more preferably less than about 0.7.

[0138] In some embodiments, the ratio between the length of the support element and the length of the rod of the aerosol-generating substrate is about 0.3 to about 0.9, preferably about 0.4 to about 0.9, and more preferably about 0.5 to about 0.9. In other embodiments, the ratio between the length of the support element and the length of the rod of the aerosol-generating substrate is about 0.3 to about 0.8, preferably about 0.4 to about 0.8, and more preferably about 0.5 to about 0.8. In further embodiments, the ratio between the length of the support element and the length of the rod of the aerosol-generating substrate is about 0.3 to about 0.7, preferably about 0.4 to about 0.7, and more preferably about 0.5 to about 0.7.

[0139] In a particularly preferred embodiment, the ratio between the length of the support element and the length of the rod of the aerosol-generating substrate is about 0.66.

[0140] The ratio between the length of the support element and the overall length of the aerosol-generating article substrate may be from about 0.125 to about 0.375.

[0141] Preferably, the ratio between the length of the support element and the overall length of the aerosol-generating article substrate is at least about 0.13, more preferably at least about 0.14, and even more preferably at least about 0.15. The ratio between the length of the support element and the overall length of the aerosol-generating article substrate is preferably less than about 0.3, more preferably less than about 0.25, and even more preferably less than about 0.20.

[0142] In some embodiments, the ratio between the length of the support element and the overall length of the aerosol-generating article substrate is preferably about 0.13 to about 0.3, more preferably about 0.14 to about 0.3, and even more preferably about 0.15 to about 0.3. In other embodiments, the ratio between the length of the support element and the overall length of the aerosol-generating article substrate is preferably about 0.13 to about 0.25, more preferably about 0.14 to about 0.25, and even more preferably about 0.15 to about 0.25. In further embodiments, the ratio between the length of the support element and the overall length of the aerosol-generating article substrate is preferably about 0.13 to about 0.2, more preferably about 0.14 to about 0.2, and even more preferably about 0.15 to about 0.2.

[0143] In a particularly preferred embodiment, the ratio between the length of the support element and the overall length of the aerosol-generating article substrate is about 0.18.

[0144] In aerosol-generating articles according to the present invention, the support element preferably has an average radial hardness of at least about 80 percent, more preferably at least about 85 percent, and even more preferably at least about 90 percent, such that the support element can provide the aerosol-generating article with the desired level of hardness.

[0145] If desired, the radial stiffness of the support element of an aerosol-generating article according to the present invention may be further increased by surrounding the support element with a stiff plug wrap, such as a plug wrap having a basis weight of at least about 80 grams per square meter (gsm), or at least about 100 gsm, or at least about 110 gsm.

[0146] When inserting an aerosol-generating article according to the present invention into an aerosol-generating device to heat the aerosol-generating substrate, the user may need to apply some force to overcome the resistance to insertion of the aerosol-generating substrate of the aerosol-generating article. This may damage one or both of the aerosol-generating article and the aerosol-generating device. In addition, the application of force during insertion of the aerosol-generating article into the aerosol-generating device may displace the aerosol-generating substrate within the aerosol-generating article. This may result in the heating element of the aerosol-generating device not being properly aligned with the susceptor element provided within the aerosol-generating substrate, leading to uneven and inefficient heating of the aerosol-generating substrate of the aerosol-generating article. Advantageously, the support element is configured to resist downstream movement of the aerosol-generating substrate during insertion of the article into the aerosol-generating device.

[0147] Preferably, the hollow tubular segment of the support element is adapted to generate an RTD of from about 0 millimeters of H2O (about 0 Pa) to about 20 millimeters of H2O (about 100 Pa), more preferably from about 0 millimeters of H2O (about 0 Pa) to about 10 millimeters of H2O (about 100 Pa). Thus, the support element preferably does not contribute to the overall RTD of the aerosol-generating article.

[0148] In some embodiments, where the intermediate hollow section includes both a support element comprising a first hollow tubular segment and an aerosol cooling element comprising a second hollow tubular segment, the inner diameter (D STS ) is the inner diameter (D FTS ) is preferably greater than

[0149] More specifically, the inner diameter (D STS ) and the inner diameter (D FTS ) is preferably at least about 1.25. More preferably, the ratio between the inner diameter (D STS ) and the inner diameter (D FTS ) is preferably at least about 1.3. Even more preferably, the ratio between the inner diameter (D STS ) and the inner diameter (D FTS ) is preferably at least about 1.4. In particularly preferred embodiments, the ratio between the inner diameter (D STS ) and the inner diameter (D FTS ) is at least about 1.5, more preferably at least about 1.6.

[0150] The inner diameter (D STS ) and the inner diameter (D FTS ) is preferably about 2.5 or less. More preferably, the ratio between the inner diameter (D STS ) and the inner diameter (DFTS ) is preferably about 2.25 or less. Even more preferably, the ratio between the inner diameter (D STS ) and the inner diameter (D FTS ) is preferably about 2 or less.

[0151] In some embodiments, the inner diameter (D STS ) and the inner diameter (D FTS ) is about 1.25 to about 2.5. STS ) and the inner diameter (D FTS ) is about 1.3 to about 2.5. STS ) and the inner diameter (D FTS ) is about 1.4 to about 2.5. In a particularly preferred embodiment, the ratio of the inner diameter (D STS ) and the inner diameter (D FTS ) is about 1.5 to about 2.5.

[0152] In other embodiments, the inner diameter (D STS ) and the inner diameter (D FTS ) is about 1.25 to about 2.25. STS ) and the inner diameter (D FTS ) is about 1.3 to about 2.25. STS ) and the inner diameter (D FTS ) is about 1.4 to about 2.25. In a particularly preferred embodiment, the ratio of the inner diameter (D STS ) and the inner diameter (D FTS ) is about 1.5 to about 2.25.

[0153] In a further embodiment, the inner diameter (D STS ) and the inner diameter (D FTS ) is about 1.25 to about 2. Preferably, the ratio between the inner diameter (D STS ) and the inner diameter (D FTS ) is about 1.3 to about 2. More preferably, the ratio of the inner diameter (D STS ) and the inner diameter (D FTS ) is about 1.4 to about 2. In a particularly preferred embodiment, the ratio of the inner diameter (D STS ) and the inner diameter (D FTS ) is about 1.5 to about 2.

[0154] In those embodiments in which the article further comprises an elongated susceptor element longitudinally disposed within the aerosol-generating substrate, the inner diameter (D FTS It is preferred that the ratio between the inner diameter (D ) of the first hollow tubular segment and the width of the susceptor element is at least about 0.2. FTS ) and the width of the susceptor element is at least about 0.3. Even more preferably, the ratio between the inner diameter (D FTS ) and the width of the susceptor element is at least about 0.4.

[0155] Additionally or alternatively, the inner diameter (D STS It is preferred that the ratio between the inner diameter (D ) of the second hollow tubular segment and the width of the susceptor element is at least about 0.2. STS ) and the width of the susceptor element is at least about 0.5. Even more preferably, the ratio between the inner diameter (D STS ) and the width of the susceptor element is at least about 0.8.

[0156] Preferably, the ratio between the volume of the cavity of the first hollow tubular segment and the volume of the cavity of the second hollow tubular segment is at least about 0.1. More preferably, the ratio between the volume of the cavity of the first hollow tubular segment and the volume of the cavity of the second hollow tubular segment is at least about 0.2. Even more preferably, the ratio between the volume of the cavity of the first hollow tubular segment and the volume of the cavity of the second hollow tubular segment is at least about 0.3.

[0157] Preferably, the ratio between the volume of the cavity of the first hollow tubular segment and the volume of the cavity of the second hollow tubular segment is about 0.9 or less. More preferably, the ratio between the volume of the cavity of the first hollow tubular segment and the volume of the cavity of the second hollow tubular segment is about 0.7 or less. Even more preferably, the ratio between the volume of the cavity of the first hollow tubular segment and the volume of the cavity of the second hollow tubular segment is about 0.5 or less.

[0158] As mentioned above, the aerosol-generating article of the present invention comprises a rod of aerosol-generating substrate, which may be a solid aerosol-generating substrate.

[0159] In certain preferred embodiments, the aerosol-generating substrate comprises homogenized plant material, preferably homogenized tobacco material.

[0160] 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 an aerosol-generating substrate of the present invention may be formed by agglomerating particles of tobacco material obtained by grinding, milling, 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.

[0161] 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. The term "sheet" as used herein with respect to the present invention describes a thin layer of material having a width and length that is significantly greater than its thickness.

[0162] Alternatively, or additionally, the homogenized plant material may be in the form of a plurality of pellets or granules.

[0163] Alternatively, or additionally, the homogenized plant material may 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" is intended to encompass pieces, fragments, and any other homogenized plant material having a similar morphology. 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 methods.

[0164] In some embodiments, the strands may be formed in situ within the aerosol-generating substrate as a result of splitting or cracking of the sheet of homogenized plant material during the formation of the aerosol-generating substrate, e.g., as a result of crimping. The strands of homogenized plant material within the aerosol-generating substrate may be separated from one another. Alternatively, each strand of homogenized plant material within the aerosol-generating substrate may be at least partially connected to adjacent strands along its 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-generating substrate, as described above.

[0165] The aerosol-generating substrate is preferably in the form of one or more sheets of homogenized plant material. In various embodiments of the present invention, the one or more sheets of homogenized plant material may be produced by a casting process. In various embodiments of the present invention, the one or more sheets of homogenized plant material may be produced by a papermaking 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-generating substrate. For example, if the aerosol-generating 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, stacked within the aerosol-generating substrate.

[0166] One or more of the sheets described herein may each individually have a weight of about 100 g / m 2 ~about 300g / m 2 The sheet may have a basis weight of 1000 gram.

[0167] One or more of the sheets described herein may each individually have a density of about 0.3 g / cm 3 ~Approx. 1.3g / cm 3 and may have a density of about 0.7 g / cm 3 ~Approx. 1.0g / cm 3 It is preferred that the density of the cellulose acylate is 0.05 to 0.15.

[0168] In embodiments of the invention in which the aerosol-generating 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.

[0169] 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.

[0170] One or more sheets of homogenized plant material may be advantageously crimped or similarly treated. As used herein, the term "crimped" refers to 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.

[0171] 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.

[0172] Alternatively, one or more sheets of homogenized plant material may be cut into strands, as mentioned above. In such embodiments, the aerosol-generating substrate includes multiple strands of homogenized plant material. The strands can 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 even 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, whereby 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 transportation. In such cases, the length of some of the strands may be shorter than the length of the plugs.

[0173] The strands are preferably aligned with the longitudinal axis and extend substantially along the length of the aerosol-generating substrate, and are therefore preferably aligned substantially parallel to one another.

[0174] 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.

[0175] 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.

[0176] In certain embodiments of the present invention, the homogenized plant material is a homogenized tobacco material comprising tobacco particles. The sheets of homogenized tobacco material used in such embodiments of the present invention may have a tobacco content of at least about 40 weight percent on a dry weight basis, more preferably at least about 50 weight percent on a dry weight basis, 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.

[0177] For purposes of the present invention, the term "tobacco particles" describes particles of any plant material of the Nicotiana species. 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.

[0178] 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 types of tobacco materials 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.

[0179] Flue-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.

[0180] Burley tobacco plays an important role in many tobacco blends. Burley tobacco has a unique flavor and aroma and the ability to absorb large amounts of casing.

[0181] 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.

[0182] 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.

[0183] The tobacco particles may have a nicotine content of at least about 2.5 weight percent on a dry weight basis, more preferably at least about 3 weight percent, 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 on a dry weight basis.

[0184] In certain other embodiments of the present invention, the homogenized plant material comprises 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 these 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.

[0185] The weight ratio of non-tobacco plant flavor particles to 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-generating substrate during use. Preferably, the homogenized plant material comprises, on a dry weight basis, at least a 1:30 weight ratio of non-tobacco plant flavor particles to tobacco particles, more preferably at least a 1:20 weight ratio of non-tobacco plant flavor particles to tobacco particles, more preferably at least a 1:10 weight ratio of non-tobacco plant flavor particles to tobacco particles, and most preferably at least a 1:5 weight ratio of non-tobacco plant flavor particles to tobacco particles.

[0186] As an alternative to, or in addition to, including tobacco particles in the homogenized plant material of an aerosol-generating substrate according to the present invention, the homogenized plant material may include cannabis particles. The term "cannabis particles" refers to particles of cannabis plants, such as Cannabis sativa, Cannabis indica, and Cannabis ruderalis.

[0187] 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.

[0188] 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.

[0189] 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.

[0190] Alternatively, or additionally, the homogenized plant material may further comprise 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, 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.

[0191] Alternatively, or additionally, the homogenized plant material may further comprise a pH adjuster.

[0192] Alternatively, or in addition, the homogenized plant material may further comprise fibers to alter the mechanical properties of the homogenized plant material, where the fibers are included in the homogenized plant material during the processes 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. Prior to inclusion 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.

[0193] 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.

[0194] Alternatively, or in addition, the homogenized plant material may further comprise one or more aerosol formers. Upon volatilization, the aerosol formers can carry other vaporized compounds, such as nicotine and flavorants, that are released from the aerosol-generating substrate upon heating. Suitable aerosol formers for inclusion in the homogenized plant material are known in the art and include, but are not limited to, 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).

[0195] 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.

[0196] 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.

[0197] In another embodiment, 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 of 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-generating substrate in a manner that incorporates flavors from the aerosol-generating substrate into the aerosol.

[0198] In another embodiment, 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-generating substrates intended to be heated at temperatures below 275 degrees Celsius. In such an embodiment, 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 result in particularly effective aerosol delivery when used in an aerosol-generating substrate having an aerosol former content of 30 weight percent to 45 weight percent.

[0199] 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.

[0200] As used herein, the term "additional cellulose" encompasses any cellulose material incorporated into the homogenized plant material that is not derived from non-tobacco plant particles or tobacco particles provided therein. 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-generating substrate. For example, the additional cellulose is preferably a tasteless and odorless material.

[0201] The additional cellulose may include cellulose powder, cellulose fiber, or a combination thereof.

[0202] The aerosol former may act as a wetting agent in the aerosol-generating substrate.

[0203] 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, a sheet 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-generating substrate if the aerosol-generating substrate is to be ignited rather than heated in the intended manner.

[0204] In other preferred embodiments of the invention, the aerosol-generating substrate comprises a gel composition comprising an alkaloid compound, or a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound. In particularly preferred embodiments, the aerosol-generating substrate comprises a gel composition comprising nicotine.

[0205] 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.

[0206] 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.

[0207] 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 / total particulate matter (TPM) aerosol to the consumer, preferably in a continuous manner.

[0208] 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.

[0209] 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.

[0210] The term "alkaloid compound" refers to any one or more classes 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, e.g., 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.

[0211] The gel composition preferably comprises an alkaloid compound selected from the group consisting of nicotine, anatabine, and combinations thereof.

[0212] Preferably, the gel composition comprises nicotine.

[0213] The term "nicotine" refers to nicotine and nicotine derivatives (eg, free base nicotine, nicotine salts, and the like).

[0214] 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 naturally occurring in the cannabis plant 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.

[0215] 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.

[0216] The gel composition may preferably comprise a cannabinoid compound selected from the group consisting of cannabidiol (CBD), THC (tetrahydrocannabinol) and combinations thereof.

[0217] The gel preferably contains cannabidiol (CBD).

[0218] The gel composition may include nicotine and cannabidiol (CBD).

[0219] The gel composition may include nicotine, cannabidiol (CBD), and THC (tetrahydrocannabinol).

[0220] 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.

[0221] 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.

[0222] 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.

[0223] 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.

[0224] 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.

[0225] 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.

[0226] 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, leads to the formation of a solid medium or support matrix into a gel. Gelling agents include, but are not limited to, hydrogen-bond cross-linking gelling agents and ionic cross-linking gelling agents.

[0227] The gelling agent may comprise one or more biopolymers, which may be formed from polysaccharides.

[0228] 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.

[0229] Preferably, the gel composition contains at least about 0.2 weight percent of the hydrogen-bond cross-linked gelling agent. Alternatively or additionally, the gel composition preferably contains at least about 0.2 weight percent of the ionic cross-linked gelling agent. Most preferably, the gel composition contains at least about 0.2 weight percent of the hydrogen-bond cross-linked gelling agent and at least about 0.2 weight percent of the ionic cross-linked gelling agent. The gel composition may contain about 0.5 weight percent to about 3 weight percent of the hydrogen-bond cross-linked gelling agent and about 0.5 weight percent to about 3 weight percent of the ionic cross-linked gelling agent, or about 1 weight percent to about 2 weight percent of the hydrogen-bond cross-linked gelling agent and about 1 weight percent to about 2 weight percent of the 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.

[0230] 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.

[0231] 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.

[0232] 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.

[0233] 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.

[0234] 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.

[0235] 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.

[0236] 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.

[0237] 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.

[0238] 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.

[0239] 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.

[0240] 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.

[0241] 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.

[0242] 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.

[0243] 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.

[0244] 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.

[0245] 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.

[0246] 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.

[0247] 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.

[0248] The term "thickener" refers to a compound that, when uniformly added in an amount of 0.3 weight percent into a 50 weight percent water / 50 weight percent glycerin mixture at 25°C, increases the viscosity without resulting in the formation of a gel, and the mixture remains fluid. Preferably, the thickener, when uniformly added in an amount of 0.3 weight percent into a 50 weight percent water / 50 weight percent glycerin mixture at 25°C, increases the viscosity of the mixture without resulting in the formation of a gel, and the mixture remains fluid. -1Preferably, the thickener, when homogeneously added in an amount of 0.3 weight percent to a 50 weight percent water / 50 weight percent glycerol mixture at 25° C., increases the viscosity by 0.1 s at a shear rate of 0.3 weight percent, preferably at least 500 cPs, preferably at least 1000 cPs, without causing the formation of a gel, and the mixture remains fluid. -1 refers to a compound that increases the viscosity of a mixture at a shear rate of at least 2 times, at least 5 times, at least 10 times, or at least 100 times greater than before addition, and that maintains or preserves the mixture as a fluid.

[0249] The viscosity values ​​recited herein may be measured using a Brookfield RVT viscometer with a disc type RV#2 spindle rotating at 25° C. at a speed of 6 revolutions per minute (rpm).

[0250] 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.

[0251] 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.

[0252] 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.

[0253] 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.

[0254] 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.

[0255] 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.

[0256] 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.

[0257] 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.

[0258] 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.

[0259] 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.

[0260] 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.

[0261] 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.

[0262] 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.

[0263] 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.

[0264] 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.

[0265] 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.

[0266] 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.

[0267] Preferably, the aerosol-generating substrate contains about 150 mg to about 350 mg of the gel composition.

[0268] Preferably, in embodiments including a gel composition, the aerosol-generating substrate includes 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 transportation of the gel composition. This may help maintain the desired shape of the gel composition, particularly during manufacture, transportation, or use.

[0269] 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.

[0270] 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.

[0271] The porous media used in the present invention may be crimped or chopped. In a preferred embodiment, the porous media is crimped. In an alternative embodiment, the porous media comprises chopped porous media. The crimping or chopping process can be before or after loading the gel composition.

[0272] 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.

[0273] The shredding provides the medium with a high surface area to volume ratio so that it can readily absorb the gel.

[0274] 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.

[0275] 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.

[0276] 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.

[0277] The porous medium loaded with the gel composition is preferably provided within a tubular element that forms part of the aerosol-generating article. Ideally, the tubular element has a longitudinal length greater than its width, but this is not necessary, as the tubular element may be part of a multi-component item whose longitudinal length is greater than its width. Typically, the tubular element is cylindrical, but this is not necessary. For example, the tubular element may have an elliptical, polygonal, such as triangular or rectangular, or irregular cross section.

[0278] The tubular element preferably includes a first longitudinal passage. The tubular element is preferably formed from a wrapper that defines the first longitudinal passage. The wrapper is preferably a water-resistant wrapper. This water-resistant property of the wrapper can be achieved by using a water-resistant material or by treating the wrapper material. This can be achieved by treating one or both sides of the wrapper. Being water-resistant can help prevent loss of structure, hardness, or rigidity. This can also help prevent leakage of gel or liquid, especially when using a gel with a fluid structure.

[0279] Preferably, in embodiments in which the rod of aerosol-generating substrate comprises a gel composition, as described above, the downstream section of the aerosol-generating article comprises an aerosol cooling element having a length of less than 10 millimeters. It has been found that the use of a relatively short aerosol cooling element in combination with a gel composition optimizes the delivery of the aerosol to the consumer.

[0280] Embodiments of the present invention in which the aerosol-generating substrate rod comprises the gel composition described above preferably include an upstream element upstream of the aerosol-generating substrate rod. In this case, the upstream element advantageously prevents physical contact with the gel composition. The upstream element can also advantageously compensate for any potential decrease in RTD due to evaporation of the gel composition, for example, when the aerosol-generating substrate rod is heated during use.

[0281] In certain preferred embodiments of the present invention, the elongated susceptor element is disposed substantially longitudinally within the rod of the aerosol-generating substrate and is in thermal contact with the aerosol-generating substrate.

[0282] As used herein with respect to the present invention, the term "susceptor element" refers to a material capable of converting electromagnetic energy into heat. When positioned within a varying electromagnetic field, induced eddy currents in the susceptor element cause the susceptor element to heat. When an elongated susceptor element is positioned in thermal contact with an aerosol-generating substrate, the aerosol-generating substrate is heated by the susceptor element.

[0283] When used to describe a susceptor element, the term "elongated" means that the susceptor element has a length dimension that is greater than its width dimension or its thickness dimension, for example, greater than twice its width dimension or its thickness dimension.

[0284] The susceptor elements are disposed substantially longitudinally within the rod, meaning that the length dimension of the elongated susceptor elements is disposed approximately parallel to the longitudinal direction of the rod, for example, within ±10 degrees of parallel to the longitudinal direction of the rod. In a preferred embodiment, the elongated susceptor elements may be positioned in a radially central position within the rod and extend along the longitudinal axis of the rod.

[0285] Preferably, the susceptor element extends all the way to the downstream end of the rod of aerosol-generating article. In some embodiments, the susceptor element may extend all the way to the upstream end of the rod of aerosol-generating article. In particularly preferred embodiments, the susceptor element has substantially the same length as the rod of aerosol-generating substrate, extending from the upstream end of the rod to the downstream end of the rod.

[0286] The susceptor elements are preferably in the form of pins, rods, strips or blades.

[0287] 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.

[0288] The ratio between the length of the susceptor element and the overall length of the aerosol-generating article substrate may be from about 0.2 to about 0.35.

[0289] Preferably, the ratio between the length of the susceptor element and the overall length of the aerosol-generating article substrate is at least about 0.22, more preferably at least about 0.24, and even more preferably at least about 0.26. The ratio between the length of the susceptor element and the overall length of the aerosol-generating article substrate is preferably less than about 0.34, more preferably less than about 0.32, and even more preferably less than about 0.3.

[0290] In some embodiments, the ratio between the length of the susceptor element and the overall length of the aerosol-generating article substrate is preferably 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. In other embodiments, the ratio between the length of the susceptor element and the overall length of the aerosol-generating article substrate is preferably 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 further embodiments, the ratio between the length of the susceptor element and the overall length of the aerosol-generating article substrate 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.

[0291] In a particularly preferred embodiment, the ratio between the length of the susceptor element and the overall length of the aerosol-generating article substrate is about 0.27.

[0292] The susceptor element preferably has a width of about 1 millimeter to about 5 millimeters.

[0293] The susceptor element generally can have a thickness of about 0.01 millimeters to about 2 millimeters, for example, about 0.5 millimeters to about 2 millimeters. In some embodiments, the susceptor element preferably has a thickness of about 10 micrometers to about 500 micrometers, more preferably about 10 micrometers to about 100 micrometers.

[0294] 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.

[0295] 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.

[0296] 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.

[0297] 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.

[0298] 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.

[0299] The elongated susceptor elements preferably have a length that is the same as or shorter than the length of the aerosol-generating substrate.The elongated susceptor elements preferably have the same length as the aerosol-generating substrate.

[0300] 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-generating substrate. Preferred susceptor elements comprise metal or carbon.

[0301] 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 having similar values ​​of frequency and field strength.

[0302] Thus, any of the parameters of the susceptor element, such as type of material, length, width, and thickness, may 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.

[0303] Suitable susceptor elements may include a non-metallic core with a metal layer disposed thereon, e.g., a metal track formed on the surface of a ceramic core. The susceptor element may have a protective outer layer, e.g., 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.

[0304] The susceptor element is disposed in thermal contact with the aerosol-generating substrate, and as the temperature of the susceptor element increases, the aerosol-generating substrate is heated and an aerosol is formed. Preferably, the susceptor element is disposed in direct physical contact with the aerosol-generating substrate, for example, within the aerosol-generating substrate.

[0305] 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 used primarily 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 used primarily 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-generating substrate. Suitable materials for the second susceptor element material may include nickel and certain nickel alloys.

[0306] By providing a susceptor element having at least first and second susceptor element materials with either a second susceptor element material having a Curie temperature or a first susceptor element material without a Curie temperature, or by providing first and second susceptor element materials having different first and second Curie temperatures, the heating of the aerosol-generating substrate and the temperature control of the heating can be separated. 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 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-generating 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, for example, such that the overall average temperature of the aerosol-generating substrate does not exceed 240° C. when heated by a susceptor element having a temperature equal to the second Curie temperature.

[0307] The aerosol-generating article of the present invention can further comprise an upstream element located upstream of and adjacent to the aerosol-generating substrate, the upstream section comprising at least one upstream element. The upstream element advantageously prevents direct physical contact with the upstream end of the aerosol-generating substrate. In particular, if the aerosol-generating substrate comprises a susceptor element, the upstream element can prevent direct physical contact with the upstream end of the susceptor element. This helps to prevent displacement or deformation of the susceptor element during handling or transportation of the aerosol-generating article. This, in turn, helps to fix the shape and position of the susceptor element. Furthermore, the presence of the upstream element helps to prevent any loss of the substrate, which can be advantageous, for example, when the substrate contains particulate plant material.

[0308] The upstream element may also provide an improved appearance to the upstream end of the aerosol-generating article. Additionally, if desired, the upstream element may be used to provide information about the aerosol-generating article, such as the brand, flavor, content, or details of the aerosol-generating device in which the article is intended to be used.

[0309] The upstream element may be a porous plug element. Preferably, the porous plug element does not alter the withdrawal resistance of the aerosol-generating article. Preferably, the upstream element has a porosity of at least about 50 percent in the longitudinal direction of the aerosol-generating article. More preferably, the upstream element has a porosity of between about 50 percent and about 90 percent in the longitudinal direction. The longitudinal porosity of the upstream element is defined as the ratio of the cross-sectional area of ​​the material forming the upstream element to the internal cross-sectional area of ​​the aerosol-generating article at the location of the upstream element.

[0310] The upstream element may be made of a porous material or may comprise a plurality of openings, which may be achieved, for example, by laser drilling, and the plurality of openings are preferably homogeneously distributed across the cross section of the upstream element.

[0311] The porosity or permeability of the upstream element may be advantageously varied to provide a desired overall resistance to withdrawal of the aerosol-generating article.

[0312] Preferably, the RTD of the upstream element is at least about 5 millimeters of H2O. More preferably, the RTD of the upstream element is at least about 10 millimeters of H2O. Even more preferably, the RTD of the upstream element is at least about 15 millimeters of H2O. In a particularly preferred embodiment, the RTD of the upstream element is at least about 20 millimeters of H2O.

[0313] Preferably, the RTD of the upstream element is about 80 millimeters H2O or less. More preferably, the RTD of the upstream element is about 60 millimeters H2O or less. Even more preferably, the RTD of the upstream element is about 40 millimeters H2O or less.

[0314] In some embodiments, the RTD of the upstream element is between about 5 millimeters HO and about 80 millimeters HO, preferably between about 10 millimeters HO and about 80 millimeters HO, more preferably between about 15 millimeters HO and about 80 millimeters HO, and even more preferably between about 20 millimeters HO and about 80 millimeters HO. In other embodiments, the RTD of the upstream element is between about 5 millimeters HO and about 60 millimeters HO, preferably between about 10 millimeters HO and about 60 millimeters HO, more preferably between about 15 millimeters HO and about 60 millimeters HO, and even more preferably between about 20 millimeters HO and about 60 millimeters HO. In further embodiments, the RTD of the upstream element is between about 5 millimeters HO and about 40 millimeters HO, preferably between about 10 millimeters HO and about 40 millimeters HO, more preferably between about 15 millimeters HO and about 40 millimeters HO, and even more preferably between about 20 millimeters HO and about 40 millimeters HO.

[0315] The RTD of the upstream element is preferably greater than the RTD of the mouthpiece element. Preferably, the RTD of the upstream element is at least 1.5 times the RTD of the mouthpiece, more preferably at least twice the RTD of the mouthpiece, and more preferably at least 2.5 times the RTD of the mouthpiece element. This advantageously provides a greater proportion of the overall RTD of the aerosol-generating article upstream of the rod of aerosol-generating substrate. This minimizes the RTD of the mouthpiece element and, if necessary, minimizes its filtering effect on the aerosol.

[0316] In alternative embodiments, the upstream element may be formed from a material that is impermeable to air. In such embodiments, the aerosol-generating article may be configured to allow air to flow into the rod of aerosol-generating substrate via suitable venting means provided in the wrapper.

[0317] The upstream element may be made of any material suitable for use in an aerosol-generating article. The upstream element may be made of the same material as that used in one of the other components of the aerosol-generating article, such as the mouthpiece, cooling element, or support element. Suitable materials for the upstream element include filter material, ceramic, polymeric material, cellulose acetate, cardboard, zeolite, or an aerosol-generating substrate. The upstream element is preferably formed from a plug of cellulose acetate.

[0318] The upstream element is preferably formed from a heat resistant material, for example, a material that can withstand temperatures up to 350 degrees Celsius, to ensure that the upstream element is not adversely affected by the heating means for heating the aerosol-generating substrate.

[0319] The upstream element preferably has a diameter approximately equal to the diameter of the aerosol-generating article.

[0320] Preferably, the upstream element has a length of about 1 millimeter to about 10 millimeters, more preferably about 3 millimeters to about 8 millimeters, and even more preferably about 4 millimeters to about 6 millimeters. In a particularly preferred embodiment, the upstream element has a length of about 5 millimeters. The length of the upstream element can be advantageously varied to provide a desired overall length for the aerosol-generating article. For example, if it is desired to reduce the length of one of the other components of the aerosol-generating article, the length of the upstream element can be increased to maintain the same overall length for the article.

[0321] The upstream element preferably has a substantially homogeneous structure. For example, the upstream element may be substantially homogeneous in texture and appearance. The upstream element may, for example, have a continuous, regular surface over its entire cross section. The upstream element may, for example, not have any discernible symmetry.

[0322] The upstream element is preferably surrounded by a wrapper that is preferably a stiff plug wrap, such as a plug wrap having a basis weight of at least about 80 grams per square meter (gsm), or at least about 100 gsm, or at least about 110 gsm, to provide structural rigidity to the upstream element.

[0323] Aerosol-generating articles according to the present invention may have a length of from about 35 millimeters to about 100 millimeters.

[0324] Preferably, the overall length of an aerosol-generating article according to the present invention is at least about 38 millimeters. More preferably, the overall length of an aerosol-generating article according to the present invention is at least about 40 millimeters. Even more preferably, the overall length of an aerosol-generating article according to the present invention is at least about 42 millimeters.

[0325] Preferably, the overall length of an aerosol-generating article according to the present invention is 70 mm or less, more preferably 60 mm or less, and even more preferably 50 mm or less.

[0326] In some embodiments, the total length of the aerosol-generating article is preferably between about 38 millimeters and about 70 millimeters, more preferably between about 40 millimeters and about 70 millimeters, and even more preferably between about 42 millimeters and about 70 millimeters. In other embodiments, the total length of the aerosol-generating article is preferably between about 38 millimeters and about 60 millimeters, more preferably between about 40 millimeters and about 60 millimeters, and even more preferably between about 42 millimeters and about 60 millimeters. In further embodiments, the total length of the aerosol-generating article is preferably between about 38 millimeters and about 50 millimeters, more preferably between about 40 millimeters and about 50 millimeters, and even more preferably between about 42 millimeters and about 50 millimeters. In an exemplary embodiment, the total length of the aerosol-generating article is about 45 millimeters.

[0327] Preferably, the aerosol-generating article has an outer diameter of at least 5 millimeters. Preferably, the aerosol-generating article has an outer diameter of at least 6 millimeters. More preferably, the aerosol-generating article has an outer diameter of at least 7 millimeters.

[0328] Preferably, the aerosol-generating article has an outer diameter of about 12 millimeters or less. More preferably, the aerosol-generating article has an outer diameter of about 10 millimeters or less. Even more preferably, the aerosol-generating article has an outer diameter of about 8 millimeters or less.

[0329] In some embodiments, the aerosol-generating article has an outer diameter of about 5 mm to about 12 mm, preferably about 6 mm to about 12 mm, and more preferably about 7 mm to about 12 mm. In other embodiments, the aerosol-generating article has an outer diameter of about 5 mm to about 10 mm, preferably about 6 mm to about 10 mm, and more preferably about 7 mm to about 10 mm. In further embodiments, the aerosol-generating article has an outer diameter of about 5 mm to about 8 mm, preferably about 6 mm to about 8 mm, and more preferably about 7 mm to about 8 mm.

[0330] In certain preferred embodiments of the present invention, the diameter of the aerosol-generating article at the mouth end (D ME ) is the diameter of the aerosol-generating article at its distal end (D DE ) is (preferably) greater than the ratio between the diameter of the aerosol-generating article at its mouth end and the diameter of the aerosol-generating article at its distal end (D ME / D DE ) is (preferably) at least about 1.005.

[0331] Preferably, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is (preferably) at least about 1.01. More preferably, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is at least about 1.02. Even more preferably, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is at least about 1.05.

[0332] The ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DEPreferably, the ratio between the diameter of the aerosol-generating article at the mouth end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is about 1.25 or less. Even more preferably, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is about 1.20 or less. In particularly preferred embodiments, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is less than or equal to 1.15 or 1.10.

[0333] In some preferred embodiments, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is about 1.01 to 1.30, more preferably 1.02 to 1.30, and even more preferably 1.05 to 1.30.

[0334] In other embodiments, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is about 1.01 to 1.25, more preferably 1.02 to 1.25, and even more preferably 1.05 to 1.25. In a further embodiment, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is about 1.01 to 1.20, more preferably 1.02 to 1.20, and even more preferably 1.05 to 1.20. In still further embodiments, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is about 1.01 to 1.15, more preferably 1.02 to 1.15, and even more preferably 1.05 to 1.15.

[0335] By way of example, the outer diameter of the article may be substantially constant over a distal portion of the aerosol-generating article that extends at least about 5 millimeters or at least about 10 millimeters from the distal end. Alternatively, the outer diameter of the article may taper over a distal portion of the article that extends at least about 5 millimeters or at least about 10 millimeters from the distal end.

[0336] In certain preferred embodiments of the present invention, as described above, the elements of the aerosol-generating article are arranged so that the center of mass of the aerosol-generating article is at least about 60 percent along the length of the aerosol-generating article from the downstream end, more preferably the elements of the aerosol-generating article are arranged so that the center of mass of the aerosol-generating article is at least about 62 percent along the length of the aerosol-generating article from the downstream end, and more preferably at least about 65 percent along the length of the aerosol-generating article from the downstream end.

[0337] The center of mass is preferably no more than about 70 percent along the length of the aerosol-generating article from the downstream end.

[0338] Providing an arrangement of elements that provides a center of mass closer to the upstream end than the downstream end results in an aerosol-generating article with a weight imbalance, with the upstream end being heavier. This weight imbalance can advantageously provide tactile feedback to the consumer, enabling them to distinguish between the upstream and downstream ends and insert the correct end into the aerosol generating device. This can be particularly beneficial when the upstream elements are provided such that the upstream and downstream ends of the aerosol-generating article visually resemble each other.

[0339] In embodiments of aerosol-generating articles according to the invention, both the aerosol cooling element and the support element are present, and these are preferably wrapped together in a combined wrapper that surrounds the aerosol cooling element and the support element but does not surround anything further downstream, such as a mouthpiece element.

[0340] In these embodiments, the aerosol cooling element and support element are combined before being surrounded by the combined wrapper, and then further combined with the mouthpiece segment.

[0341] From a manufacturing standpoint, this is advantageous in that it allows shorter aerosol-generating articles to be constructed.

[0342] In general, it can be difficult to handle individual elements with lengths smaller than their diameters. For example, for a 7-millimeter diameter element, a length of about 7 millimeters represents a threshold that is desirable to remain constant. However, a 10-millimeter aerosol-cooling element can be combined with a pair of 7-millimeter support elements on each side (and potentially with other elements, such as aerosol-generating substrate rods) to provide a 24-millimeter hollow segment, which can then be cut into two intermediate 12-millimeter hollow sections.

[0343] In a particularly preferred embodiment, the other components of the aerosol-generating article are individually surrounded by their own wrappers. In other words, the upstream element, the aerosol-generating substrate rod, the support element, and the aerosol cooling element are all individually wrapped. The support element and the aerosol cooling element are combined to form an intermediate hollow section. This is achieved by wrapping the support element and the aerosol cooling element in a combined wrapper. The upstream element, the aerosol-generating substrate rod, and the intermediate hollow section are then combined together with an outer wrapper. They are then combined with a mouthpiece element having its own wrapper using tipping paper.

[0344] Preferably, at least one of the components of the aerosol-generating article is enclosed in a hydrophobic wrapper.

[0345] The term "hydrophobicity" 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 a solid surface. It quantifies the wettability of a solid surface by a liquid via Young's equation. Hydrophobicity or water contact angle may be determined by utilizing the TAPPI T558 test method, and the results are expressed as interfacial contact angles, reported in degrees, which can range from approximately zero to approximately 180 degrees.

[0346] In preferred embodiments, the hydrophobic wrapper comprises a paper layer having a water contact angle of about 30 degrees or greater, preferably about 35 degrees or greater, or about 40 degrees or greater, or about 45 degrees or greater.

[0347] By way of example, the paper layer may comprise PVOH (polyvinyl alcohol) or silicone. The PVOH may be applied to the paper layer as a surface coating, or the paper layer may include a surface treatment that includes PVOH or silicone.

[0348] In a particularly preferred embodiment, an aerosol-generating article according to the invention comprises, in a linear series arrangement, an upstream element, a rod of aerosol-generating substrate located immediately downstream of the upstream element, a support element located immediately downstream of the rod of aerosol-generating substrate, an aerosol cooling element located immediately downstream of the support element, a mouthpiece element located immediately downstream of the aerosol cooling element, and an outer wrapper surrounding the upstream element, support element, aerosol cooling element and mouthpiece element.

[0349] More particularly, the rod of the aerosol-generating substrate may abut the upstream element. The support element may abut the rod of the aerosol-generating substrate. The aerosol-cooling element may abut the support element. The mouthpiece element may abut the aerosol-cooling element.

[0350] The aerosol-generating article has a substantially cylindrical shape and an outer diameter of about 7.25 millimeters.

[0351] The upstream element has a length of about 5 mm, the rod of the aerosol-generating article has a length of about 12 mm, the support element has a length of about 8 mm, and the mouthpiece element has a length of about 12 mm, so that the total length of the aerosol-generating article is about 45 mm.

[0352] The upstream element is in the form of a plug of cellulose acetate encased in a stiff plug wrap.

[0353] The aerosol-generating article comprises an elongated susceptor element disposed substantially longitudinally within and in thermal contact with the rod of aerosol-generating substrate, the susceptor element being in the form of a strip or blade having a length substantially equal to the length of the rod of aerosol-generating substrate and a thickness of about 60 micrometers.

[0354] The support element is in the form of a hollow cellulose acetate tube and has an inner diameter of about 1.9 millimeters, so that the peripheral wall thickness of the support element is about 2.675 millimeters.

[0355] The aerosol cooling element is in the form of a finer hollow cellulose acetate tube and has an inner diameter of about 3.25 millimeters, so the peripheral wall thickness of the aerosol cooling element is about 2 millimeters.

[0356] The mouthpiece is in the form of a low density cellulose acetate filter segment.

[0357] The rod of aerosol-generating substrate comprises at least one of the types of aerosol-generating substrates described above, such as homogenized tobacco, a gel formulation, or homogenized plant material containing particles of plants other than tobacco. [Brief explanation of the drawings]

[0358] In the following, the invention will be further explained with reference to the accompanying drawing of Figure 1, which shows a schematic cross-sectional side view of an aerosol-generating article according to the invention.

[0359] [Figure 1] 1 comprises a rod 12 of aerosol-generating substrate 12 and a downstream section 14 located downstream of the rod 12 of aerosol-generating substrate. Additionally, the aerosol-generating article 10 comprises an upstream section 16 located upstream of the rod 12 of aerosol-generating substrate. Thus, the aerosol-generating article 10 may extend from an upstream or distal end 18 to a downstream or oral end 20. DETAILED DESCRIPTION OF THE INVENTION

[0360] The aerosol-generating article has a total length of about 45 millimeters.

[0361] The downstream section 14 comprises a support element 22 located immediately downstream of the rod 12 of the aerosol-generating substrate, the support element 22 being longitudinally aligned with the rod 12. In the embodiment of Figure 1, the upstream end of the support element 18 abuts the downstream end of the rod 12 of the aerosol-generating substrate. The downstream section 14 further comprises an aerosol-cooling element 24 located immediately downstream of the support element 22, the aerosol-cooling element 24 being longitudinally aligned with the rod 12 and the support element 22. In the embodiment of Figure 1, the upstream end of the aerosol-cooling element 24 abuts the downstream end of the support element 22.

[0362] As will become apparent from the following description, the support element 22 and the aerosol cooling element 24 together define an intermediate hollow section 50 of the aerosol-generating article 10. As a whole, the intermediate hollow section 50 does not contribute substantially to the overall RTD of the aerosol-generating article. The RTD of the intermediate hollow section 26 as a whole is substantially 0 millimeters HO.

[0363] The support element 22 may include a first hollow tubular segment 26. The first hollow tubular segment 26 is provided in the form of a hollow cylindrical tube made from cellulose acetate. The first hollow tubular segment 26 defines an interior cavity 28 extending entirely from the upstream end 30 of the first hollow tubular segment to the downstream end 32 of the first hollow tubular segment 20. The interior cavity 28 is substantially empty, thus allowing substantially unrestricted airflow along the interior cavity 28. The first hollow tubular segment 26, and consequently the support element 22, does not substantially contribute to the overall RTD of the aerosol-generating article 10. More specifically, the RTD of the first hollow tubular segment 26 (which is substantially the RTD of the support element 22) is substantially 0 millimeters HO.

[0364] The first hollow tubular segment 26 has a length of about 8 millimeters, an outer diameter of about 7.25 millimeters, and an inner diameter (D FTS ) The peripheral wall thickness of the first hollow tubular segment 26 is therefore approximately 2.67 millimeters.

[0365] The aerosol cooling element 24 includes a second hollow tubular segment 34. The second hollow tubular segment 34 is provided in the form of a hollow cylindrical tube made from cellulose acetate. The second hollow tubular segment 34 defines an interior cavity 36 extending entirely from the upstream end 38 of the second hollow tubular segment to the downstream end 40 of the second hollow tubular segment 34. The interior cavity 36 is substantially empty, thus allowing substantially unrestricted airflow along the interior cavity 36. The second hollow tubular segment 28, and consequently the aerosol cooling element 24, does not substantially contribute to the overall RTD of the aerosol-generating article 10. More specifically, the RTD of the second hollow tubular segment 34 (which is essentially the RTD of the aerosol cooling element 24) is substantially 0 millimeters HO.

[0366] The second hollow tubular segment 34 has a length of about 8 millimeters, an outer diameter of about 7.25 millimeters, and an inner diameter (D STS) of the first hollow tubular segment 26. The thickness of the peripheral wall of the second hollow tubular segment 34 is therefore about 2 millimeters. FTS ) and the inner diameter (D STS ) is about 0.75.

[0367] The aerosol-generating article 10 includes a ventilation zone 60 provided at a location along the second hollow tubular segment 34. More specifically, the ventilation zone is provided approximately 2 millimeters from the upstream end of the second hollow tubular segment 34. The ventilation level of the aerosol-generating article 10 is approximately 25 percent.

[0368] 1, downstream section 14 further comprises a mouthpiece element 42 at a location downstream of intermediate hollow section 50. More particularly, mouthpiece element 42 is positioned immediately downstream of aerosol cooling element 24. As shown in the drawing of FIG. 1, the upstream end of mouthpiece element 42 abuts downstream end 40 of aerosol cooling element 18.

[0369] Mouthpiece element 42 is provided in the form of a cylindrical plug of low density cellulose acetate.

[0370] Mouthpiece element 42 has a length of about 12 millimeters and an outer diameter of about 7.25 millimeters. The RTD of mouthpiece element 42 is about 12 millimeters H2O.

[0371] The rod 12 includes an aerosol-generating substrate of one of the types described above.

[0372] The aerosol-generating substrate rod 12 has an outer diameter of about 7.25 millimeters and a length of about 12 millimeters.

[0373] The aerosol-generating article 10 further comprises an elongated susceptor element 44 within the rod 12 of the aerosol-generating substrate. More particularly, the susceptor element 44 is disposed substantially longitudinally within the aerosol-generating substrate, generally parallel to the longitudinal direction of the rod 12. As shown in the drawing of 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 12.

[0374] The susceptor element 44 extends completely from the upstream end to the downstream end of the rod 12. In practice, the susceptor element 44 has substantially the same length as the rod 12 of the aerosol-generating substrate.

[0375] In the embodiment of Figure 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. The upstream section 16 includes an upstream element 46 located immediately upstream of the aerosol-generating substrate rod 12, the upstream element 46 being longitudinally aligned with the rod 12. In the embodiment of Figure 1, the downstream end of the upstream element 46 abuts the upstream end of the aerosol-generating substrate rod 12. This advantageously prevents the susceptor element 44 from becoming dislodged. This further ensures that consumers cannot accidentally come into contact with the heated susceptor element 44 after use.

[0376] 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.

Claims

1. 1. An aerosol-generating article for producing an inhalable aerosol upon heating, said aerosol-generating article comprising: a rod of an aerosol-generating substrate; a mouthpiece element having a length of at least 10 millimeters; an intermediate hollow section between the rod of the aerosol-generating substrate and the mouthpiece element, the intermediate hollow section comprising an aerosol cooling element axially aligned with the mouthpiece element and abutting the upstream end of the mouthpiece element, the aerosol cooling element having a length of less than 10 millimeters and comprising a hollow tubular segment defining a longitudinal cavity providing an unrestricted flow channel, the hollow tubular segment having a wall thickness of less than 2.5 millimeters.

2. 10. The aerosol-generating article of claim 1, wherein the hollow tubular segment of the aerosol cooling element has a wall thickness of at least 1.5 millimeters.

3. 3. The aerosol-generating article of claim 1, wherein the length of the mouthpiece element is at least 2 millimeters longer than the length of the aerosol-cooling element.

4. 4. The aerosol-generating article of claim 1, wherein the aerosol cooling element includes a ventilation zone provided at a location along the hollow tubular segment of the aerosol cooling element.

5. 5. An aerosol-generating article according to claim 1, wherein the intermediate hollow section further defines a support element between the aerosol cooling element and the rod of the aerosol-generating substrate, the support element comprising a hollow tubular segment.

6. 6. An aerosol-generating article according to claim 5, wherein the ratio between the inner diameter of the hollow tubular segment of the aerosol-cooling element and the inner diameter of the hollow tubular segment of the support element is preferably at least about 1.

25.

7. 7. The aerosol-generating article of claim 1, wherein the inner diameter of the hollow tubular segment of the aerosol cooling element is at least about 3 millimeters.

8. The aerosol cooling element has a drawing resistance of 10 mmH 2 The aerosol-generating article according to any one of claims 1 to 7, wherein the viscosity is less than 0.

9. 9. An aerosol-generating article according to claim 1, wherein the intermediate hollow section has a length of about 18 millimeters or less.

10. 10. The aerosol-generating article according to claim 1, further comprising an upstream element provided upstream of the rod of the aerosol-generating substrate.

11. The resistance to withdrawal (RTD) of the upstream element is at least 20 mmH 2 The aerosol-generating article of claim 10, wherein

12. 12. An aerosol-generating article according to claim 10 or 11, wherein the resistance to draw (RTD) of the upstream element is at least twice the resistance to draw (RTD) of the mouthpiece element.

13. 13. An aerosol-generating article according to any preceding claim, wherein the length of the mouthpiece element is at least 0.4 times the length of the intermediate hollow section.

14. 14. An aerosol-generating article according to any preceding claim, wherein the rod of aerosol-generating substrate further comprises an elongated susceptor element extending longitudinally through the rod of aerosol-generating substrate.

15. 15. An aerosol-generating article according to any preceding claim, wherein the rod of aerosol-generating substrate comprises a gel composition.

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