Aerosol-generating article comprising a coated susceptor element

Abstract

An aerosol-generating article (10) for generating an inhalable aerosol upon heating is provided. The aerosol-generating article (10) comprises an aerosol-generating element (12) comprising an aerosol-generating substrate. The aerosol-generating substrate comprises a homogenized tobacco material comprising an aerosol former. The aerosol-generating article further comprises a susceptor (44) disposed within the aerosol-generating element (12) and configured to heat the homogenized tobacco material. The susceptor (44) is coated with a coating composition comprising at least 20 weight percent of the aerosol former. The coating composition further comprises isolated nicotine or a monobasic nicotine salt, or both.

Description

[Technical field]

[0001] The present invention relates to an aerosol-generating article comprising an aerosol-generating substrate and 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, 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. Such devices include, for example, electrically heated aerosol generating devices, in which 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, an inductively heated aerosol-generating article has been proposed by WO2015 / 176898, which includes an aerosol-generating substrate and a susceptor disposed within the aerosol-generating substrate.

[0004] Aerosol-generating articles in which the tobacco-containing substrate is heated rather than combusted present a number of challenges not found in 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 the release of nicotine from the tobacco-containing substrate and the delivery of nicotine 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.

[0005] Second, it typically takes time to heat a tobacco-containing aerosol-generating substrate to one of those temperatures required for aerosol formation, which may delay aerosol delivery to the consumer. When a user first draws on the article, the aerosol that reaches the user may be relatively low in flavor or nicotine content, or both, often referred to as the "cold puff" or "empty puff" effect.

[0006] For example, one such delay may be detectable in aerosol-generating rods and articles in which the aerosol-generating substrate comprises homogenized tobacco material, as the aerosol former and nicotine may not be particularly readily available for release, particularly when using cast leaf homogenized tobacco material prepared from a slurry containing the aerosol former, as opposed to one in which the aerosol former is applied (e.g., sprayed) onto a formed sheet.

[0007] Previously, it has been proposed to address this by providing two or more independent heating zones within the device in which the aerosol-generating rod or article is heated, which allows different heating profiles to be implemented for different parts of the aerosol-generating substrate, which can help combat the "cold puff" effect.

[0008] However, it would be desirable to provide new and improved aerosol-generating rods or articles adapted to address the initial "cold puff" or "empty puff" effect. For example, it would be desirable to provide new and improved aerosol-generating rods or articles that can more quickly provide a satisfactory aerosol delivery to the user and that generally allow finer adjustment of the aerosol delivery during use.

[0009] It would be particularly desirable to provide such new and improved aerosol generating rods or articles which are capable of generating satisfactory aerosol delivery to the user at lower temperatures while still heating the tobacco-containing substrate for normal consumption.

[0010] In general, it would be desirable to provide an aerosol-generating article that is adapted to address the initial "cold puff" or "empty puff" effect, is easy to use, and may have improved utility.

[0011] It would be desirable to provide such an aerosol-generating rod or article that could be efficiently and rapidly manufactured without requiring extensive modifications of existing equipment.

[0012] It would therefore be desirable to provide new and improved aerosol-generating articles adapted to achieve at least one of the above desired results. Summary of the Invention

[0013] The present disclosure relates to an aerosol-generating article for generating an inhalable aerosol upon heating. The aerosol-generating article may comprise an aerosol-generating element comprising an aerosol-generating substrate. The aerosol-generating substrate may comprise a homogenized tobacco material comprising an aerosol former. The aerosol-generating article may further comprise a susceptor disposed within the aerosol-generating element and configured to heat the homogenized tobacco material. The susceptor may be coated with a coating composition. The coating composition may comprise at least 20 weight percent of the aerosol former. The coating composition may further comprise isolated nicotine or a monobasic nicotine salt, or both.

[0014] According to the present invention there is provided an aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising: an aerosol-generating element comprising an aerosol-generating substrate, the aerosol-generating substrate comprising a homogenized tobacco material comprising an aerosol former; and a susceptor disposed within the aerosol-generating element and configured to heat the homogenized tobacco material, the susceptor being coated with a coating composition comprising at least 20 percent by weight of the aerosol former, the coating composition comprising isolated nicotine or a monobasic nicotine salt or both.

[0015] In contrast to existing aerosol-generating articles, the aerosol-generating article according to the present invention comprises a susceptor coated with a coating composition comprising a predetermined amount of an aerosol former and isolated nicotine or a nicotine salt or both.

[0016] The inventors have discovered that by thermally bonding a susceptor coated with such a composition to a homogenized tobacco-based aerosol-generating substrate, it is advantageously possible to at least partially avoid the initial delay in aerosol generation and delivery often observed with existing aerosol-generating articles.

[0017] Without wishing to be bound by theory, it is understood that the nicotine in the coating composition - whether present in isolated form, as a monobasic acid, or both - and the aerosol formers are more readily available than the nicotine and aerosol formers contained in the homogenized tobacco material. It is further understood that during the initial heating cycle, the heat generated by induction through the susceptor is rapidly and directly transferred to the coating composition, and thus an initial burst of nicotine-containing aerosol can be provided to the consumer while the bulk temperature of the substrate, including the homogenized tobacco material surrounding the coating susceptor, continues to increase. Thus, once the aerosol emanating from the homogenized tobacco material begins to be released at a satisfactory rate and with the desired flavor and nicotine content, this flow provides a sustained release of aerosol for the remainder of the usage cycle.

[0018] By adjusting the content of aerosol formers and nicotine in the composition, and the ratio of the content of aerosol formers and nicotine in the composition to the corresponding contents in the homogenized tobacco material, it is advantageously possible to fine-tune the transition from one aerosol source to the other, in particular so that the transition is particularly smooth and undetectable to the consumer.

[0019] FIG. 1 qualitatively illustrates how the aerosol delivery from each of the homogenized tobacco substrate and the coating composition provided on the susceptor changes over time. As shown by line A in FIG. 1, the aerosol is rapidly released from the coating composition upon initiation of heating of the article, rapidly reaches a maximum value, and then decreases almost rapidly. Because the content of aerosol species in the coating composition decreases relatively quickly, the aerosol emission from the coating composition essentially stops after a relatively short period of time. On the other hand, the aerosol emission from the homogenized tobacco substrate, represented by line B, is not very high at first, and only reaches a comparable level with the aerosol emission from the homogenized tobacco substrate after the aerosol emission from the coating composition begins to decrease. By the time the aerosol emission from the coating composition nearly stops, the aerosol emission from the homogenized tobacco substrate will have more than doubled in intensity, only to decrease smoothly over a long period of time covering the remainder of the use cycle of the article.

[0020] At any given time during use, the consumer receives substantially the sum of the flow of aerosol species emitted from the coating composition provided on the susceptor and the flow of aerosol species emitted from the homogenized tobacco substrate. The dotted line C in FIG. 1 illustrates this effect during the initial portion of the article's use cycle. As can be seen from the graph, the aerosol emission from the coating composition provided on the susceptor makes up for the initial delay in aerosol emission from the homogenized tobacco substrate until the latter substantially takes over. This is perceived by the consumer as an overall more rapid, uniform and consistent aerosol delivery throughout the use cycle of the article as compared to existing aerosol-generating articles.

[0021] Below will also be described methods that allow aerosol-generating articles that provide one or more of the above-mentioned advantages to be manufactured on existing production lines without requiring major reconfiguration thereof.

[0022] As briefly described above, the present invention provides an aerosol-generating article for producing an inhalable aerosol upon heating. The aerosol-generating article comprises an aerosol-generating element comprising an aerosol-generating substrate.

[0023] 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 releasing a volatile compound upon heating to generate an aerosol.

[0024] 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 the transfer of heat 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 aerosol-generating substrate. Aerosol-generating articles of this type are described in the prior art, for example in EP0822670.

[0025] 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.

[0026] The aerosol-generating element may be in the form of a rod. 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.

[0027] The term "longitudinal" as used herein 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. The terms "upstream" and "downstream" as used herein describe the relative positions of an element (or part of an element) of the aerosol-generating article with respect to the direction in which aerosol is transported through the aerosol-generating article during use.

[0028] 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.

[0029] The term "length" refers to the dimension of a component of an aerosol-generating article in a longitudinal direction. For example, it may be used to refer to the dimension of a rod or elongated tubular element in a longitudinal direction.

[0030] The aerosol-generating substrate is a solid aerosol-generating substrate, more particularly, the aerosol-generating substrate comprises homogenized tobacco material.

[0031] Homogenized tobacco material is an example of a "homogenized plant material." 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, crushing, or comminuting 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.

[0032] The homogenized tobacco material can be provided in any suitable form. For example, the homogenized tobacco material may be in the form of one or more sheets. As used herein with respect to the present invention, the term "sheet" describes a layered element having a width and length substantially greater than its thickness. The homogenized tobacco material may be in the form of a plurality of pellets or granules.

[0033] The homogenized tobacco material may be in the form of multiple strands, strips, or pieces. As used herein, the term "strand" describes an elongated element of material having a width and length substantially greater than its width and thickness. The term "strand" should be considered to encompass strips, pieces, and any other homogenized tobacco material having a similar form. Strands of homogenized tobacco material may be formed from a sheet of homogenized tobacco material, for example, by cutting or chopping, or by other methods, such as extrusion methods.

[0034] In some embodiments, the strands may be formed in situ within the aerosol-generating substrate as a result of splitting or breaking of a sheet of homogenized tobacco material during formation of the aerosol-generating substrate, for example as a result of crimping. The strands of homogenized tobacco material within the aerosol-generating substrate may be separated from one another. Alternatively, each strand of homogenized tobacco material within the aerosol-generating substrate may be at least partially connected to adjacent strands along the length of the strand. 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 a sheet of homogenized tobacco material during manufacture of the aerosol-generating substrate, as described above.

[0035] The aerosol-generating substrate is preferably in the form of one or more sheets of homogenized tobacco material. In various embodiments of the invention, the one or more sheets of homogenized tobacco material may be produced by a casting process. In various embodiments of the invention, the one or more sheets of homogenized tobacco material may be produced by a papermaking process. The one or more sheets described herein may each individually have a thickness of from 100 micrometers to 600 micrometers, preferably from 150 micrometers to 300 micrometers, and most preferably from 200 micrometers to 250 micrometers. Individual thickness refers to the thickness of an individual sheet, and combined thickness refers to the total thickness of all sheets that make up 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, and the two sheets are stacked within the aerosol-generating substrate.

[0036] 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 weight may have a number of grams.

[0037] 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 granular material is 0.01 to 0.15.

[0038] In embodiments of the invention in which the aerosol-generating substrate comprises one or more sheets of homogenized tobacco 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 sheet of homogenized tobacco material is spiraled, folded, or otherwise compressed or pinched in a direction substantially transverse to the cylindrical axis of the plug or rod.

[0039] One or more sheets of homogenized tobacco material may be gathered transversely to their longitudinal axes and surrounded by a wrapper to form a continuous rod or plug.

[0040] One or more sheets of homogenized tobacco 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 in addition to being crimped, one or more sheets of homogenized tobacco material may be embossed, debossed, perforated, or otherwise deformed to provide texture to one or both sides of the sheet.

[0041] Preferably, each sheet of homogenized tobacco 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 tobacco material to form the plug. Preferably, one or more sheets of homogenized tobacco material may be assembled. Of course, the crimped sheets of homogenized tobacco 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 disturbed at the plurality of parallel ridges or corrugations, causing separation of the material and resulting in the formation of fragments, strands, or strips of homogenized tobacco material.

[0042] Alternatively, one or more sheets of homogenized tobacco material may be cut into strands, as mentioned above. In such an embodiment, the aerosol-generating substrate comprises a plurality of strands of homogenized tobacco material. The strands may be used to form plugs. Typically, such strands have a width of about 5 millimeters, or about 4 millimeters, or about 3 millimeters, or about 2 millimeters, or less. The length of the strands may be greater than about 5 millimeters, about 5 millimeters to about 15 millimeters, about 8 millimeters to about 12 millimeters, or about 12 millimeters. The strands preferably have substantially the same length as one another. The length of the strands may be determined by the manufacturing process whereby the rod is cut into shorter plugs, the length of the strands corresponding to the length of the plugs. The strands are fragile and may break, especially during transition. In such cases, the length of some of the strands may be shorter than the length of the plugs.

[0043] The strands preferably extend substantially longitudinally along the length of the aerosol-generating substrate, aligned with the longitudinal axis, and thus preferably are aligned substantially parallel to one another.

[0044] The homogenized tobacco material may comprise up to about 95 weight percent plant particles on a dry weight basis. Preferably, the homogenized tobacco material comprises up to about 90 weight percent plant particles on a dry weight basis, more preferably comprises up to about 80 weight percent plant particles, more preferably comprises up to about 70 weight percent plant particles, more preferably comprises up to about 60 weight percent plant particles, and more preferably comprises up to about 50 weight percent plant particles.

[0045] For example, the homogenized tobacco material may 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.

[0046] Sheets of homogenized tobacco material used in the present invention may have a tobacco content of at least about 40 weight percent on a dry weight basis, more preferably at least about 50 weight percent on a dry weight basis, more preferably at least about 70 weight percent on a dry weight basis, and most preferably at least about 90 weight percent on a dry weight basis.

[0047] In the context of the present invention, the term "tobacco particles" refers to particles of any plant member 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 a preferred embodiment, the tobacco particles are substantially entirely derived from tobacco lamina. In contrast, isolated nicotine and nicotine salts, which are compounds derived from tobacco, are not considered tobacco particles for purposes of the present invention and are not included in the percentage of particulate plant material.

[0048] 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.

[0049] Flame-curing is a tobacco curing method used specifically with Virginia tobacco. During the flue-curing process, heated air is circulated through tightly packed tobacco. During the first stage, the tobacco leaves turn yellow and wither. During the second stage, the leaf lamina dries completely. During the third stage, the leaf stem dries completely.

[0050] Burley tobacco plays an important role in many tobacco blends. It has a unique flavor and aroma, and the ability to absorb large amounts of casing.

[0051] Orient is a type of tobacco that has small leaves and high aromatic qualities. However, Orient tobacco has a milder flavor than, for example, Burley. Thus, Orient tobacco is generally used in relatively small proportions in tobacco blends.

[0052] Kasturi, Madura, and Jatim are subtypes of sun-cured tobacco that may be used. Preferably, Kasturi and flue-cured tobaccos are used in a blend to produce tobacco particles. Thus, the tobacco particles in the particulate plant material may comprise a blend of Kasturi and flue-cured tobaccos.

[0053] The tobacco particles may have a nicotine content of at least about 2.5 weight percent based on dry weight. More preferably, the tobacco particles may have a nicotine content of at least about 3 weight percent based on dry weight, 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.

[0054] In certain other embodiments of the present invention, the homogenized tobacco material may include tobacco particles in combination with non-tobacco plant flavor particles. Preferably, the non-tobacco plant flavor particles are selected from one or more of ginger particles, eucalyptus particles, clove particles, and star anise particles. Preferably, in such embodiments, the homogenized tobacco material includes at least about 2.5 weight percent of non-tobacco plant flavor particles on a dry weight basis, with the remaining plant particles being tobacco particles. Preferably, the homogenized tobacco material includes at least about 4 weight percent of non-tobacco plant flavor particles on a dry weight basis, 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, more preferably at least about 10 weight percent of non-tobacco plant flavor particles. Preferably, the homogenized tobacco material includes up to about 20 weight percent of non-tobacco plant flavor particles, more preferably up to about 18 weight percent of non-tobacco plant flavor particles, more preferably up to about 16 weight percent of non-tobacco plant flavor particles.

[0055] The weight ratio of non-tobacco plant flavour particles and tobacco particles in the particulate plant material forming the homogenized tobacco material may vary depending on the desired flavour characteristics and composition of the aerosol generated from the aerosol-generating substrate during use. Preferably, the homogenized tobacco material comprises, on a dry weight basis, at least a 1:30 weight ratio of non-tobacco plant flavour particles to tobacco particles, more preferably at least a 1:20 weight ratio of non-tobacco plant flavour particles to tobacco particles, more preferably at least a 1:10 weight ratio of non-tobacco plant flavour particles to tobacco particles, and most preferably at least a 1:5 weight ratio of non-tobacco plant flavour particles to tobacco particles.

[0056] The homogenized tobacco 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 tobacco material.

[0057] The homogenized tobacco material may further comprise a binder for modifying the mechanical properties of the particulate plant material, where the binder is included in the homogenized tobacco material during manufacture as described herein.Suitable extrinsic 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, conjugate base salts of organic acids such as agar and pectin, and combinations thereof.Preferably, the binder comprises guar gum.

[0058] 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 tobacco material, preferably in an amount of about 2 weight percent to about 5 weight percent, based on the dry weight of the homogenized tobacco material.

[0059] Alternatively, or in addition, the homogenized tobacco material may further include one or more lipids to enhance the diffusion rate of volatile components (e.g., aerosol-forming agents, gingerols, and nicotine), where the lipids are included in the homogenized tobacco material during manufacture as described herein. Suitable lipids for inclusion within the homogenized tobacco material include, but are not limited to, medium chain triglycerides, cocoa butter, palm oil, palm kernel oil, mango oil, shea butter, soybean oil, cottonseed oil, coconut oil, hydrogenated coconut oil, candellila wax, carnauba wax, shellac, sunflower wax, sunflower oil, rice bran, and Revel A, and combinations thereof.

[0060] Alternatively, or additionally, the homogenized tobacco material may further include a pH adjuster.

[0061] Alternatively or additionally, the homogenized tobacco material may further include fibers to alter the mechanical properties of the homogenized tobacco material, the fibers being included within the homogenized tobacco material during manufacture as described herein. Suitable exogenous fibers for inclusion in the homogenized tobacco 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 tobacco material are not considered to form part of the "particulate plant material" as defined above. Prior to inclusion within the homogenized tobacco material, the fibers may be treated by any 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.

[0062] 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.

[0063] In the context of the present invention, the homogenized tobacco material further comprises one or more aerosol formers. Upon volatilization, the aerosol formers can carry other vaporized compounds released from the aerosol-generating substrate upon heating, such as nicotine and flavorants in the aerosol. Aerosol formers suitable for inclusion within the homogenized tobacco 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 dimethyl tetradecanedioate).

[0064] The homogenized tobacco material may have an aerosol former content of about 5 to about 30 weight percent on a dry weight basis. Preferably, the homogenized tobacco material has an aerosol former content of at least about 10 weight percent on a dry weight basis, and more preferably, at least about 15 weight percent on a dry weight basis.

[0065] The homogenized tobacco material preferably has an aerosol former content of greater than or equal to about 25 weight percent on a dry weight basis, and more preferably greater than or equal to about 20 weight percent on a dry weight basis.

[0066] In some embodiments, the homogenized tobacco material has an aerosol former content of from 5 weight percent to 25 weight percent on a dry weight basis, preferably from 10 weight percent to 25 weight percent on a dry weight basis, more preferably from 15 weight percent to 25 weight percent on a dry weight basis. In other embodiments, the homogenized tobacco material has an aerosol former content of from 5 weight percent to 20 weight percent on a dry weight basis, preferably from 10 weight percent to 20 weight percent on a dry weight basis, more preferably from 15 weight percent to 20 weight percent on a dry weight basis.

[0067] In other embodiments, the homogenized tobacco 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 embodiments, the homogenized tobacco material preferably further comprises, on a dry weight basis, about 2 weight percent to about 10 weight percent of 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 cellulose ether and additional cellulose has been found to provide particularly effective aerosol delivery when used in an aerosol-generating substrate having an aerosol former content of 30 weight percent to 45 weight percent.

[0068] 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.

[0069] As used herein, the term "additional cellulose" encompasses any cellulose material incorporated into the homogenized tobacco material that is not derived from non-tobacco plant particles or tobacco particles provided in the homogenized tobacco material. Thus, the additional cellulose is incorporated into the homogenized tobacco material as an individual and separate cellulose source to any cellulose essentially provided within the non-tobacco plant particles or tobacco particles, in addition to the non-tobacco plant materials or tobacco materials. 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, which 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.

[0070] The additional cellulose may include cellulose powder, cellulose fibers, or a combination thereof.

[0071] The aerosol former may act as a wetting agent in the aerosol-generating substrate.

[0072] The aerosol-generating elements, including the aerosol-generating substrate, may be surrounded by a wrapper, which may be a paper wrapper or a non-paper wrapper. Suitable paper wrappers for use in certain embodiments of the present invention are known in the art and include, but are not limited to, cigarette paper and filter plug wrap. Suitable non-paper wrappers for use in certain embodiments of the present invention are known in the art and include, but are not limited to, sheets of homogenized tobacco material. In certain preferred embodiments, the wrapper may be formed from a laminate material comprising multiple layers. The wrapper is preferably 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 substrate is to be ignited rather than heated in the intended manner.

[0073] As briefly described above, in an aerosol-generating article according to the invention, a susceptor is disposed within the aerosol-generating element and configured to heat an aerosol-generating substrate, such as a homogenized tobacco material, and further coated with a coating composition, which is described in more detail below.

[0074] As used herein with respect to the present invention, the term "susceptor" refers to a material capable of converting electromagnetic energy into heat. When located within a varying electromagnetic field, induced eddy currents in the susceptor cause heating of the susceptor. The elongated susceptor is thermally coupled, such as being located in thermal contact with, an aerosol-generating substrate, and the aerosol-generating substrate is heated by the susceptor.

[0075] Preferably, the coated susceptor is surrounded by the aerosol-generating substrate. In a preferred embodiment, the coated susceptor is surrounded by homogenized tobacco material, and in a particularly preferred embodiment, by homogenized tobacco material.

[0076] More preferably, the susceptor is an elongated susceptor. When used to describe a susceptor, the term "elongated" means that the susceptor has a length dimension that is greater than its width or its thickness dimension, for example, greater than twice its width or its thickness dimension.

[0077] The susceptor element is preferably disposed substantially longitudinally within the aerosol generating element, meaning that the length dimension of the elongated susceptor is disposed approximately parallel to the longitudinal axis of the aerosol generating element, for example within ±10 degrees of parallel to the longitudinal axis of the aerosol generating element. In a preferred embodiment, the elongated susceptor element may be positioned at a radially central location within the elongated susceptor element and extend along the longitudinal axis of the aerosol generating element, the aerosol generating element being provided in the form of a rod.

[0078] By way of example, a coated elongated susceptor may be positioned substantially longitudinally within a rod of aerosol-generating substrate containing homogenized tobacco material such that the susceptor is thermally coupled to the aerosol-generating substrate.

[0079] Preferably, the susceptor extends all the way to the downstream end of the aerosol generating element. In some embodiments, the susceptor may extend all the way to the upstream end of the aerosol generating element. In particularly preferred embodiments, the susceptor has substantially the same length as the aerosol generating element and extends from the upstream end of the rod to the downstream end of the aerosol generating element.

[0080] The susceptor is preferably in the form of a pin, rod, strip or blade.

[0081] The susceptor 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.

[0082] The ratio between the length of the susceptor and the overall length of the aerosol-generating article may be from about 0.2 to about 0.35.

[0083] Preferably, the ratio between the length of the susceptor and the overall length of the aerosol-generating article is at least about 0.22, more preferably at least about 0.24, and even more preferably at least about 0.26. The ratio between the length of the susceptor and the overall length of the aerosol-generating article is preferably less than about 0.34, more preferably less than about 0.32, and even more preferably less than about 0.3.

[0084] In some embodiments, the ratio between the length of the susceptor and the total length of the aerosol-generating article 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 and the total length of the aerosol-generating article 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 and the total length of the aerosol-generating article is preferably about 0.22 to about 0.3, more preferably about 0.24 to about 0.3, and even more preferably about 0.26 to about 0.3.

[0085] In a particularly preferred embodiment, the ratio between the length of the susceptor and the overall length of the aerosol-generating article is about 0.27.

[0086] Preferably, the susceptor has a width of about 1 millimeter to about 6 millimeters. More preferably, the susceptor has a width of at least about 2 millimeters. Even more preferably, the susceptor has a width of at least about 3 millimeters. In particularly preferred embodiments, the susceptor has a width of about 4 or 5 millimeters. This is believed to maximize the surface area available for heat transfer while ensuring that the susceptor is completely surrounded by the aerosol-generating substrate.

[0087] The susceptor may generally 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 preferably has a thickness of about 10 micrometers to about 500 micrometers, more preferably about 10 micrometers to about 100 micrometers.

[0088] When the susceptor has a uniform cross-section, such as a circular cross-section, it has a preferred width or diameter of about 1 millimeter to about 5 millimeters.

[0089] When the susceptor has the form of a strip or blade, the strip or blade preferably has a rectangular shape with a width of about 2 millimeters to about 8 millimeters, more preferably about 3 millimeters to about 5 millimeters. By way of example, a susceptor in the form of a blade strip may have a width of about 4 millimeters.

[0090] When the susceptor has the form of a strip or blade, the strip or blade preferably has 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 in the form of a strip blade may have a thickness of about 0.07 millimeters.

[0091] In a preferred embodiment, the elongated susceptor (in the form of a strip or blade, preferably having a rectangular shape) has a thickness of about 55 micrometers to about 65 micrometers.

[0092] More preferably, the elongated susceptor has a thickness of about 57 micrometers to about 63 micrometers. Even more preferably, the elongated susceptor has a thickness of about 58 micrometers to about 62 micrometers. In a particularly preferred embodiment, the elongated susceptor has a thickness of about 60 micrometers.

[0093] Without wishing to be bound by theory, the inventors believe that, overall, the selection of a given thickness of the susceptor is also influenced by the constraints set by the selected length and width of the susceptor, as well as the constraints set by the geometry and dimensions of the rod of the aerosol-generating substrate. As an example, the length of the susceptor is preferably selected to match the length of the aerosol-generating element. The width of the susceptor should preferably be selected to prevent displacement of the susceptor within the substrate, while also allowing easy insertion during manufacture.

[0094] The inventors have found that susceptors having a thickness within the above ranges, in aerosol-generating articles provided to inductively supply heat during use, advantageously generate and distribute heat throughout the aerosol-generating substrate in a particularly effective and efficient manner. Without wishing to be bound by theory, the inventors believe that such susceptors are adapted to provide optimal heat generation and heat transfer due to the surface area and inductive power of the susceptor. In contrast, thinner susceptors may be too easily deformed to maintain the desired shape and orientation within the rod of the aerosol-generating substrate during manufacture of the aerosol-generating article, resulting in a less uniform and finely tuned heat distribution during use. At the same time, thicker susceptors may be more difficult to cut to precise and consistent lengths, which may also affect how the susceptor is provided accurately in longitudinal alignment within the rod of the aerosol-generating substrate, and thus the uniformity of the heat distribution within the rod. These beneficial effects are especially felt when the susceptor extends all the way to the downstream end of the aerosol-generating article rod, since there is no aerosol-generating substrate within the rod downstream of the susceptor that could contribute to resistance to draw (RTD), essentially minimizing RTD downstream of the susceptor.

[0095] Without being bound by theory, the inventors believe that the most downstream portion of the aerosol-generating element can act to some extent as a filter for the more upstream portions of the aerosol-generating element. The inventors therefore believe that it would be desirable to be able to uniformly heat the most downstream portion of the aerosol-generating element as well, so that it actively participates in the release of volatile aerosol species, contributing to the overall generation and delivery of the aerosol, and that any filtering effects that may impede the delivery of the aerosol to the consumer are actively countered by the release of volatile aerosol species throughout the aerosol-generating element.

[0096] The susceptor 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 susceptors include metal or carbon.

[0097] A preferred susceptor may include or consist of a ferromagnetic material (e.g., a ferromagnetic alloy, ferritic iron, or a ferromagnetic steel or stainless steel). A suitable susceptor may be or include aluminum. A preferred susceptor may be formed from 400 series stainless steel, such as grade 410, or grade 420, or grade 430 stainless steel. Different materials dissipate different amounts of energy when positioned in an electromagnetic field having similar values ​​of frequency and field strength.

[0098] Thus, the parameters of the susceptor, such as type of material, length, width, and thickness, may all be modified to provide the desired power dissipation within a known electromagnetic field. Preferred susceptors may be heated to temperatures in excess of 250 degrees Celsius.

[0099] A suitable susceptor may comprise a non-metallic core having a metal layer disposed thereon (e.g., a track of metal formed on the surface of a ceramic core). The susceptor may have a protective outer layer, such as a protective ceramic or glass layer, that encapsulates the susceptor. The susceptor may consist of a protective layer formed of glass, ceramic, or an inert metal that extends over a core of susceptor material.

[0100] The susceptor is positioned in thermal communication with the aerosol-generating substrate such that an increased temperature of the susceptor heats the aerosol-generating substrate and forms an aerosol.

[0101] The susceptor may be a multi-material susceptor and may include a first susceptor material and a second susceptor material. The first susceptor material is placed in close physical contact with the second susceptor material. The second susceptor material preferably has a Curie temperature below 500 degrees Celsius. The first susceptor material is preferably used primarily to heat the susceptor when it is placed in a fluctuating electromagnetic field. Any suitable material may be used. For example, the first susceptor material may be aluminum or an iron-based material such as stainless steel. The second susceptor material is preferably used primarily to indicate when the susceptor has reached a particular temperature, the temperature being the Curie temperature of the second susceptor material. The Curie temperature of the second susceptor material may be used to regulate the temperature of the entire susceptor during operation. Therefore, the Curie temperature of the second susceptor material should be below the ignition point of the aerosol-generating substrate. Suitable materials for the second susceptor material may include nickel and certain nickel alloys.

[0102] The heating of the aerosol-generating substrate and the temperature control of the heating can be decoupled by providing a susceptor having at least a first and a second susceptor material with a second susceptor material having a Curie temperature and a first susceptor material having no Curie temperature, or by providing a first and a second susceptor material having first and second Curie temperatures different from each other. The first susceptor material is preferably a magnetic material having a Curie temperature of more than 500 degrees Celsius. From the viewpoint of heating efficiency, it is desirable that the Curie temperature of the first susceptor material exceeds any maximum temperature to which the susceptor can be heated. The second Curie temperature may be selected to be preferably less than 400 degrees Celsius, preferably less than 380 degrees Celsius, or less than 360 degrees Celsius. The second susceptor material is preferably a magnetic material selected to have a second Curie temperature that is substantially the same as the desired maximum heating temperature. That is, the second Curie temperature is preferably about the same as the temperature to which the susceptor should be heated in order to generate an aerosol from the aerosol-generating substrate. The second Curie temperature may, for example, be in the range of 200 degrees Celsius to 400 degrees Celsius, or in the range of 250 degrees Celsius to 360 degrees Celsius. The second Curie temperature of the second susceptor material may, for example, be selected such that the overall average temperature of the aerosol-generating substrate does not exceed 240 degrees Celsius when heated by a susceptor that is at a temperature equal to the second Curie temperature.

[0103] In those embodiments in which the susceptor is in the form of a strip or blade, the gram weight of the susceptor is at least about 350 grams per square meter, preferably at least about 400 grams per square meter, and more preferably at least about 450 grams per square meter. Preferably, in such embodiments, the gram weight of the susceptor is no more than about 650 grams per square meter, more preferably no more than about 600 grams per square meter, and even more preferably no more than about 550 grams per square meter. In certain preferred embodiments, the gram weight of the susceptor is about 500 grams per square meter.

[0104] In aerosol-generating articles according to the invention, the susceptor may have a density of at least about 5 grams per cubic centimeter, preferably at least about 6 grams per cubic centimeter, and more preferably at least about 7 grams per cubic centimeter. The susceptor preferably has a density of about 11 grams per cubic centimeter or less, more preferably about 10 grams per cubic centimeter or less, and even more preferably about 9 grams per cubic centimeter or less. In certain preferred embodiments, the susceptor has a density of about 8 grams per cubic centimeter.

[0105] In the aerosol-generating article according to the present invention, the susceptor is coated with a coating composition. As used herein, the term "coated" means that a layer including the coating composition is provided on the outer surface of the susceptor. It is not limited by the mechanism or method of forming or applying the coating on the outer surface of the susceptor. As an example, the coating composition can be applied on the outer surface of the susceptor by spraying, dip-coating, extruding the coating composition on the susceptor.

[0106] In some embodiments, the entire outer surface of the susceptor is coated, which may also be described as a "continuous coating." In other embodiments, only a portion of the outer surface of the susceptor is coated, which may also be described as a "discontinuous coating," since the coating effectively forms coated and uncoated areas on the outer surface of the susceptor.

[0107] Preferably, at least 50 percent of the surface area of ​​the outer surface of the susceptor is coated with the coating composition. More preferably, at least 75 percent of the surface area of ​​the outer surface of the susceptor is coated with the coating composition. Even more preferably, at least 90 percent of the surface area of ​​the outer surface of the susceptor is coated with the coating composition. Most preferably, at least 95 percent of the surface area of ​​the outer surface of the susceptor is coated with the coating composition. In some particularly preferred embodiments, substantially the entire surface area of ​​the outer surface of the susceptor is coated with the coating composition.

[0108] The coating composition forms a layer on the outer surface of the susceptor. The thickness of the layer of the coating composition can be controlled by adjusting parameters such as the viscosity of the slurry before starting the application process. Furthermore, different application techniques such as dipping and spraying can be selectively used to control the thickness of the layer of the coating composition.

[0109] The layer of the coating composition may have a thickness of at least 1 micrometer. Preferably, the layer of the coating composition has a thickness of at least 2 micrometers, more preferably at least 3 micrometers, and even more preferably at least 4 micrometers. In a particularly preferred embodiment, the layer of the coating composition has a thickness of at least about 5 micrometers, more preferably about 6 micrometers.

[0110] The layer of the coating composition may have a thickness of up to about 100 micrometers. Preferably, the layer of the coating composition has a thickness of about 50 micrometers or less, more preferably about 30 micrometers or less, and even more preferably about 15 micrometers or less. In a particularly preferred embodiment, the layer of the coating composition has a thickness of about 12 micrometers or less, more preferably about 10 micrometers or less.

[0111] In some embodiments, the layer of the coating composition has a thickness of about 2 micrometers to about 50 micrometers, preferably about 3 micrometers to about 50 micrometers, more preferably about 4 micrometers to about 50 micrometers, even more preferably about 5 micrometers to about 50 micrometers, and most preferably about 6 micrometers to about 50 micrometers. In other embodiments, the layer of the coating composition has a thickness of about 2 micrometers to about 30 micrometers, preferably about 3 micrometers to about 30 micrometers, more preferably about 4 micrometers to about 30 micrometers, even more preferably about 5 micrometers to about 30 micrometers, and most preferably about 6 micrometers to about 30 micrometers. In further embodiments, the layer of the coating composition has a thickness of about 2 micrometers to about 15 micrometers, preferably about 3 micrometers to about 15 micrometers, more preferably about 4 micrometers to about 15 micrometers, even more preferably about 5 micrometers to about 15 micrometers, and most preferably about 6 micrometers to about 15 micrometers. In additional embodiments, the layer of the coating composition has a thickness of about 2 micrometers to about 12 micrometers, preferably about 3 micrometers to about 12 micrometers, more preferably about 4 micrometers to about 12 micrometers, even more preferably about 5 micrometers to about 30 micrometers, and most preferably about 6 micrometers to about 12 micrometers. In still further embodiments, the layer of the coating composition has a thickness of about 2 micrometers to about 10 micrometers, preferably about 3 micrometers to about 10 micrometers, more preferably about 4 micrometers to about 10 micrometers, even more preferably about 5 micrometers to about 10 micrometers, and most preferably about 6 micrometers to about 10 micrometers.

[0112] The total weight of coating composition present in an aerosol-generating article according to the present invention may be from about 1 milligram to about 4 milligrams, preferably from about 1 milligram to about 3 milligrams, and more preferably from about 1 milligram to about 2 milligrams.

[0113] The sum of the total weight of the aerosol-generating substrate in the aerosol-generating element and the total weight of the coating composition in the aerosol-generating article according to the present invention may be from about 150 milligrams to about 500 milligrams, preferably from about 180 milligrams to about 400 milligrams, more preferably from about 200 milligrams to about 300 milligrams. In a particularly preferred embodiment, the sum of the total weight of the aerosol-generating substrate in the aerosol-generating element and the total weight of the coating composition is about 250 milligrams.

[0114] As mentioned above, in the aerosol-generating article according to the present invention, the coating composition comprises at least 20 weight percent of an aerosol former. In addition, the coating composition comprises isolated nicotine or a monobasic nicotine salt, or both. Upon heating, the coating composition described herein is adapted to provide a nicotine-containing aerosol to the lungs at an inhalation dose or airflow rate within the inhalation dose or airflow rate of a conventional smoking regimen.

[0115] The coating composition preferably comprises from about 0.5 weight percent to about 10 weight percent of isolated nicotine or monobasic nicotine salt, or both. More preferably, the coating composition comprises from about 1 weight percent to about 3 weight percent of isolated nicotine or monobasic nicotine salt, or both. Even more preferably, the coating composition comprises from about 1.5 weight percent to about 2.5 weight percent of isolated nicotine or monobasic nicotine salt, or both. In some preferred embodiments, the coating composition comprises about 1.5 weight percent of isolated nicotine or monobasic nicotine salt, or both. The coating composition may comprise about 2 weight percent of isolated nicotine or monobasic nicotine salt, or both.

[0116] The nicotine component of the coating composition may be the most volatile component of the coating composition. In some embodiments, water may be the most volatile component of the coating composition and the nicotine component of the coating composition may be the second most volatile component of the coating composition.

[0117] As mentioned above, the aerosol-generating substrate comprises a homogenized tobacco material with an aerosol former. Thus, the total weight of nicotine in the aerosol-generating article substantially corresponds to the sum of the nicotine content in the coating composition and the nicotine content in the homogenized tobacco material. The nicotine content in the coating composition may account for at least about 0.1 weight percent of the total nicotine content in the aerosol-generating article as a whole. Preferably, the nicotine content in the coating composition accounts for at least about 0.25 weight percent of the total nicotine content in the aerosol-generating article as a whole. More preferably, the nicotine content in the coating composition accounts for at least about 0.5 weight percent of the total nicotine content in the aerosol-generating article as a whole.

[0118] The nicotine content in the coating composition preferably accounts for at least about 10 weight percent or less of the total nicotine content in the aerosol-generating article as a whole. More preferably, the nicotine content in the coating composition accounts for at least about 5 weight percent or less of the total nicotine content in the aerosol-generating article as a whole. Even more preferably, the nicotine content in the coating composition accounts for at least 2 weight percent or less of the total nicotine content in the aerosol-generating article as a whole.

[0119] In some embodiments, the nicotine content in the coating composition preferably accounts for about 0.1 to about 10 weight percent of the total nicotine content in the aerosol-generating article as a whole. Preferably, the nicotine content in the coating composition preferably accounts for about 0.25 to about 10 weight percent of the total nicotine content in the aerosol-generating article as a whole. More preferably, the nicotine content in the coating composition preferably accounts for about 0.5 to about 10 weight percent of the total nicotine content in the aerosol-generating article as a whole. In other embodiments, the nicotine content in the coating composition preferably accounts for about 0.1 to about 15 weight percent of the total nicotine content in the aerosol-generating article as a whole. Preferably, the nicotine content in the coating composition preferably accounts for about 0.25 to about 5 weight percent of the total nicotine content in the aerosol-generating article as a whole. More preferably, the nicotine content in the coating composition preferably accounts for about 0.5 to about 5 weight percent of the total nicotine content in the aerosol-generating article as a whole. In a further embodiment, the nicotine content in the coating composition preferably accounts for about 0.1 to about 2 weight percent of the total nicotine content in the aerosol-generating article as a whole. Preferably, the nicotine content in the coating composition preferably accounts for about 0.25 to about 2 weight percent of the total nicotine content in the aerosol-generating article as a whole. More preferably, the nicotine content in the coating composition preferably accounts for about 0.5 to about 2 weight percent of the total nicotine content in the aerosol-generating article as a whole.

[0120] The coating composition 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, glycerin, etc.), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate, dimethyl tetradecanedioate, etc.). The polyhydric alcohol or mixtures 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.

[0121] As briefly described above, the coating composition includes at least 20 weight percent aerosol formers. The coating composition can include from about 20 weight percent aerosol formers to about 90 weight percent aerosol formers, such as from about 30 weight percent aerosol formers to about 80 weight percent aerosol formers, or from about 40 weight percent aerosol formers to about 70 weight percent aerosol formers, etc. In some preferred embodiments, the coating composition can include about 50 weight percent aerosol formers.

[0122] In particular, the composition may include from about 20 weight percent glycerol to about 90 weight percent glycerol, such as from about 30 weight percent glycerol to about 80 weight percent glycerol, or from about 40 weight percent glycerol to about 70 weight percent glycerol. In some preferred embodiments, the coating composition may include about 50 weight percent glycerol.

[0123] The coating composition comprises a majority of the aerosol former. The coating composition may comprise a mixture of water and aerosol former, with the aerosol former forming a majority (by weight) of the coating composition. The aerosol former may form at least about 50 percent by weight of the coating composition. The aerosol former may form at least about 60 percent by weight, or at least about 65 percent by weight, or at least about 70 percent by weight of the coating composition. The aerosol former may form about 70 percent to about 80 percent by weight of the coating composition. The aerosol former may form about 70 percent to about 75 percent by weight of the coating composition.

[0124] The coating composition may, in particular, comprise a majority of glycerol. The coating composition may comprise a mixture of water and glycerol, with glycerol forming the majority (by weight) of the coating composition. Glycerol may form at least about 50 weight percent of the coating 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 coating composition. Glycerol may form about 70 weight percent to about 80 weight percent of the coating composition.

[0125] Glycerol may form about 70 percent to about 75 percent by weight of the coating composition.

[0126] As noted above, the aerosol-generating substrate comprises a homogenized tobacco material comprising an aerosol former, and thus the total content of aerosol former in the aerosol-generating article substantially corresponds to the sum of the content of aerosol former in the coating composition and the content of aerosol former in the homogenized tobacco material.

[0127] The aerosol former content in the coating composition may comprise at least about 0.1 weight percent of the total aerosol former content in the aerosol-generating article as a whole. Preferably, the aerosol former content in the coating composition comprises at least about 0.25 weight percent of the total aerosol former content in the aerosol-generating article as a whole. More preferably, the aerosol former content in the coating composition comprises at least about 0.5 weight percent of the total aerosol former content in the aerosol-generating article as a whole.

[0128] The aerosol former content in the coating composition preferably accounts for about 10 weight percent or less of the total aerosol former content in the aerosol-generating article as a whole. More preferably, the aerosol former content in the coating composition accounts for about 5 weight percent or less of the total aerosol former content in the aerosol-generating article as a whole. Even more preferably, the aerosol former content in the coating composition accounts for 2 weight percent or less of the total aerosol former content in the aerosol-generating article as a whole.

[0129] In some embodiments, the aerosol former content in the coating composition preferably accounts for about 0.1 weight percent to about 10 weight percent of the total aerosol former content in the aerosol-generating article as a whole. Preferably, the aerosol former content in the coating composition preferably accounts for about 0.25 weight percent to about 10 weight percent of the total aerosol former content in the aerosol-generating article as a whole. More preferably, the aerosol former content in the coating composition preferably accounts for about 0.5 weight percent to about 10 weight percent of the total aerosol former content in the aerosol-generating article as a whole. In other embodiments, the aerosol former content in the coating composition preferably accounts for about 0.1 weight percent to about 15 weight percent of the total aerosol former content in the aerosol-generating article as a whole. Preferably, the aerosol former content in the coating composition preferably accounts for about 0.25 weight percent to about 5 weight percent of the total aerosol former content in the aerosol-generating article as a whole. More preferably, the aerosol former content in the coating composition preferably accounts for about 0.5 weight percent to about 5 weight percent of the total aerosol former content in the aerosol-generating article as a whole. In a further embodiment, the aerosol former content in the coating composition preferably accounts for about 0.1 weight percent to about 2 weight percent of the total aerosol former content in the aerosol-generating article as a whole. Preferably, the aerosol former content in the coating composition preferably accounts for about 0.25 weight percent to about 2 weight percent of the total aerosol former content in the aerosol-generating article as a whole. More preferably, the aerosol former content in the coating composition preferably accounts for about 0.5 weight percent to about 2 weight percent of the total aerosol former content in the aerosol-generating article as a whole.

[0130] In a preferred embodiment, the glycerol content of the coating composition may account for at least about 0.1 weight percent of the total aerosol former content in the aerosol-generating article as a whole. Preferably, the glycerol content of the coating composition accounts for at least about 0.25 weight percent of the total aerosol former content in the aerosol-generating article as a whole. More preferably, the glycerol content of the coating composition accounts for at least about 0.5 weight percent of the total aerosol former content in the aerosol-generating article as a whole.

[0131] The glycerol content of the coating composition as a whole preferably accounts for about 10 weight percent or less of the total aerosol former content in the aerosol-generating article. More preferably, the glycerol content of the coating composition as a whole accounts for about 5 weight percent or less of the total aerosol former content in the aerosol-generating article. Even more preferably, the glycerol content of the coating composition as a whole accounts for about 2 weight percent or less of the total aerosol former content in the aerosol-generating article.

[0132] In some preferred embodiments, the glycerol content in the coating composition preferably accounts for about 0.1 weight percent to about 10 weight percent of the total aerosol former content in the aerosol-generating article as a whole. Preferably, the glycerol content in the coating composition preferably accounts for about 0.25 weight percent to about 10 weight percent of the total aerosol former content in the aerosol-generating article as a whole. More preferably, the glycerol content in the coating composition preferably accounts for about 0.5 weight percent to about 10 weight percent of the total aerosol former content in the aerosol-generating article as a whole. In other embodiments, the glycerol content in the coating composition preferably accounts for about 0.1 weight percent to about 15 weight percent of the total aerosol former content in the aerosol-generating article as a whole. Preferably, the glycerol content in the coating composition preferably accounts for about 0.25 weight percent to about 5 weight percent of the total aerosol former content in the aerosol-generating article as a whole. More preferably, the glycerol content in the coating composition preferably accounts for about 0.5 weight percent to about 5 weight percent of the total aerosol former content in the aerosol-generating article as a whole. In a further embodiment, the glycerol content in the coating composition preferably accounts for about 0.1 weight percent to about 2 weight percent of the total aerosol former content in the aerosol-generating article as a whole. Preferably, the glycerol content in the coating composition preferably accounts for about 0.25 weight percent to about 2 weight percent of the total aerosol former content in the aerosol-generating article as a whole. More preferably, the glycerol content in the coating composition preferably accounts for about 0.5 weight percent to about 2 weight percent of the total aerosol former content in the aerosol-generating article as a whole.

[0133] In certain preferred embodiments of the present invention, the coating composition further comprises at least one gelling agent. In other words, the coating composition is preferably a gel composition. Preferably, the at least one gelling agent forms a solid medium, the aerosol former is dispersed in the solid medium, and isolated nicotine or monobasic nicotine salt or both are dispersed in the aerosol former.

[0134] 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 leading to a gel. Gelling agents include, but are not limited to, hydrogen bond cross-linking gelling agents and ionic cross-linking gelling agents.

[0135] The gelling agent may comprise one or more biopolymers. The biopolymers may be formed from polysaccharides.

[0136] Biopolymers include, for example, gellan gum (preferably native gellan gum, low acyl gellan gum, high acyl gellan gum, low acyl gellan gum), xanthan gum, alginate (alginic acid), agar, guar gum, etc. It may be preferred that the composition comprises xanthan gum. The composition may comprise two biopolymers. The composition may comprise three biopolymers. The composition may comprise two biopolymers in substantially equal amounts by weight. The composition may comprise three biopolymers in substantially equal amounts by weight.

[0137] The gel composition is preferably a stable gel phase. Advantageously, the stable gel composition comprising nicotine provides a predictable composition form upon storage or upon 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 upon 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.

[0138] 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 temperature and pressure with relative humidity varying from about 10 percent to about 60 percent. For example, a stable gel can substantially maintain its shape and mass when exposed to standard temperature and pressure with relative humidity varying from about 10 percent to about 60 percent.

[0139] The coating composition preferably includes one or more gelling agents. In certain preferred embodiments, the gelling agent includes carboxymethylcellulose (CMC) or hydroxypropylmethylcellulose (HPMC), or both. Preferably, in these embodiments, the aerosol former includes glycerol.

[0140] Preferably, the coating composition comprises a total amount of gelling agent in the range of about 0.4 weight percent to about 10 weight percent. More preferably, the coating composition comprises a total amount of gelling agent in the range of about 0.5 weight percent to about 8 weight percent. More preferably, the coating composition comprises a total amount of gelling agent in the range of about 1 weight percent to about 6 weight percent. More preferably, the coating composition comprises a total amount of gelling agent in the range of about 2 weight percent to about 4 weight percent. More preferably, the coating composition comprises a total amount of gelling agent in the range of about 2 weight percent to about 3 weight percent.

[0141] The aerosol-generating article of the present invention may preferably further comprise a downstream section at a location downstream of the aerosol-generating element. As will become apparent from the following description of different embodiments of the aerosol-generating article of the present invention, the downstream section may comprise one or more downstream elements.

[0142] The downstream section may comprise a support element disposed in alignment with and downstream of the aerosol-generating element, in particular the support element may be located immediately downstream of the aerosol-generating element and may abut the rod of the aerosol-generating substrate.

[0143] 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.

[0144] The support element may comprise a hollow tubular segment. In a preferred embodiment, the support element comprises a hollow cellulose acetate tube.

[0145] The support element is disposed substantially in alignment with the rod, meaning that the length dimension of the support element is disposed 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.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] The support element may have a length of from about 5 millimeters to about 15 millimeters.

[0150] Preferably, the support element has a length of at least about 6 millimeters, and more preferably, has a length of at least about 7 millimeters.

[0151] In a preferred embodiment, the support element has a length of less than about 12 millimeters, more preferably less than about 10 millimeters.

[0152] 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.

[0153] In a preferred embodiment, the support element has a length of about 8 millimeters.

[0154] Preferably, the overall length of the intermediate hollow section is about 18 millimeters or less, more preferably about 17 millimeters or less, more preferably 16 millimeters or less.

[0155] In an aerosol-generating article according to the 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. Thus, the support element can provide a desired level of hardness to the aerosol-generating article. If desired, the radial hardness of a component of the downstream section of the aerosol-generating article according to the invention, e.g., the support element, can be further increased by surrounding the aerosol-cooling element with a stiff plug wrap, e.g., 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.

[0156] The term "radial hardness" as used herein refers to the resistance to compression in a direction transverse to the longitudinal axis of the support element. The radial hardness of an aerosol-generating article around a support element may be determined by applying a load across the article at the location of the support 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: Radial hardness (%)=(D d / D S )*100 D in the formula S is the original (undepressed) diameter, and D d is the depressed diameter after a set load is applied for a set duration. The harder the material, the closer the hardness will be to 100 percent.

[0157] To determine the hardness of a portion of an aerosol-generating article (such as a support element provided in the form of a hollow tube segment), the aerosol-generating articles should be aligned parallel in a plane and the same portion of each aerosol-generating article tested should be subjected to a set load for a set duration. This test is carried out using a well-known DD60A Densimeter instrument (manufactured and commercially available by Heinr Borgwaldt GmbH, Germany), which is fitted with a measuring head for aerosol-generating articles such as cigarettes, and with an aerosol-generating article container.

[0158] The load is applied using two load application cylindrical rods that extend across the diameter of all the aerosol-generating articles at once. According to the standard test method for this instrument, the test should be performed so that twenty contact points are created between the aerosol-generating articles and the load application 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 create twenty contact points where each smoking article contacts both load application rods (because they are long enough to extend between both rods). In other cases, where the support element is too short to achieve this, twenty aerosol-generating articles should be used to create twenty contact points, with each aerosol-generating article contacting only one of the load application rods, as discussed further below.

[0159] Two further fixed cylindrical rods are positioned below the aerosol-generating article to support the aerosol-generating article and counter the load exerted by each of the load-applying cylindrical rods.

[0160] For the standard operating procedure for such devices, a total load of 2 kg is applied for 20 seconds. After the 20 seconds have elapsed (and the load is still applied to the smoking article), the depression on the load application cylindrical rod is determined and then used to calculate the hardness from the above equation. The temperature is kept within the range of 22 degrees Celsius ± 2 degrees Celsius. The above test is called the DD60A test. The standard method of measuring filter hardness is when the aerosol-generating article has not yet been consumed. Additional information regarding the measurement of average radial hardness can be found, for example, in U.S. Published Patent Application Publication No. 2016 / 0128378.

[0161] During insertion of the aerosol-generating article according to the invention into an aerosol-generating device for heating the aerosol-generating substrate, the user may need to apply some force to overcome the resistance to the 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 provided in the aerosol-generating substrate, leading to uneven and inefficient heating of the aerosol-generating substrate of the aerosol-generating article. The support element is advantageously configured to resist downstream movement of the aerosol-generating substrate during insertion of the article into the aerosol-generating device.

[0162] Preferably, the hollow tubular segment of the support element is adapted to generate an RTD of approximately 0 millimeters of H2O (about 0 Pa) to approximately 20 millimeters of H2O (about 100 Pa), more preferably approximately 0 millimeters of H2O (about 0 Pa) to approximately 10 millimeters of H2O (about 100 Pa). Thus, the support element preferably does not contribute to the overall RTD of the aerosol-generating article.

[0163] In certain preferred embodiments, the downstream section of the aerosol-generating article comprises a mouthpiece element positioned downstream of and in longitudinal alignment with the aerosol-generating element.

[0164] The mouthpiece element is preferably located at the downstream or mouth end of the aerosol-generating article and extends all the way to the mouth end of the aerosol-generating article.

[0165] Preferably, the mouthpiece element comprises at least one mouthpiece filter segment of fibrous filtration material for filtering the aerosol generated from the aerosol-generating substrate. Suitable fibrous filtration materials will be 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.

[0166] The mouthpiece element may consist of a single mouthpiece filter segment. The mouthpiece element may include two or more mouthpiece filter segments axially aligned in abutting end-to-end relationship with one another.

[0167] The downstream section may comprise an oral end cavity at a downstream end downstream of the mouthpiece element as described above. The oral end cavity may be defined by a hollow tubular element provided at the downstream end of the mouthpiece. The oral end cavity may be defined by an outer wrapper of the mouthpiece element, the outer wrapper extending in a downstream direction from the mouthpiece element.

[0168] The mouthpiece element may optionally include a flavourant, which may be provided in any suitable form, for example, the mouthpiece element may comprise one or more capsules, beads, or granules of flavourant, or one or more threads or filaments loaded with flavour.

[0169] In aerosol-generating articles according to the invention, the mouthpiece element forms part of the downstream section and is therefore located downstream of the aerosol-generating element.

[0170] In certain preferred embodiments, the downstream section of the aerosol-generating article further comprises both a support element located immediately downstream from the aerosol-generating element, and a mouthpiece element located downstream from the support element.

[0171] Preferably, the mouthpiece element has a low particle filtration efficiency.

[0172] Preferably, the mouthpiece is formed from a segment of fibrous filtration material.

[0173] The mouthpiece element is preferably surrounded by a plug wrap. The mouthpiece element is preferably non-ventilated so that air does not enter the aerosol-generating article along the mouthpiece element.

[0174] The mouthpiece element is preferably connected to one or more of the adjacent upstream components of the aerosol-generating article by a leading wrapper.

[0175] Preferably, the mouthpiece elements have an RTD of less than about 25 millimeters HO. More preferably, the mouthpiece elements have an RTD of less than about 20 millimeters HO. Even more preferably, the mouthpiece elements have an RTD of less than about 15 millimeters HO.

[0176] 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 and therefore provide substantially no filtering effect on the aerosol delivered to the consumer.

[0177] 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.

[0178] The mouthpiece element preferably has a length of at least about 5 millimeters, more preferably at least about 8 millimeters, more preferably at least about 10 millimeters. The mouthpiece element may preferably have a length of less than about 25 millimeters, more preferably less than about 20 millimeters, more preferably less than about 15 millimeters.

[0179] In some embodiments, the mouthpiece element preferably has a length of about 5 millimeters to about 25 millimeters, more preferably about 8 millimeters to about 25 millimeters, and even more preferably about 10 millimeters to about 25 millimeters. In other embodiments, the mouthpiece element preferably has a length of about 5 millimeters to about 10 millimeters, more preferably about 8 millimeters to about 20 millimeters, and even more preferably about 10 millimeters to about 20 millimeters. In further embodiments, the mouthpiece element preferably has a length of about 5 millimeters to about 15 millimeters, more preferably about 8 millimeters to about 15 millimeters, and even more preferably about 10 millimeters to about 15 millimeters.

[0180] For example, the mouthpiece element may have a length of about 5 millimeters to about 25 millimeters, or about 8 millimeters to about 20 millimeters, or about 10 millimeters to about 15 millimeters. In a preferred embodiment, the mouthpiece element has a length of approximately 12 millimeters.

[0181] In a particularly preferred embodiment, the downstream section further comprises an aerosol cooling element located downstream of the support element, and the mouthpiece element is located downstream of both the support element and the aerosol cooling element. Particularly 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.

[0182] The aerosol cooling element may define multiple longitudinally extending channels, for example to create a high surface area available for heat exchange. The multiple longitudinally extending channels may be defined by a sheet material that is pleated, assembled, or folded to form the channels. The multiple longitudinally extending channels may be defined by a single sheet that is pleated, assembled, or folded to form the channels. The sheet may also be crimped before being pleated, assembled, or folded. Alternatively, the multiple longitudinally extending channels may be defined by multiple sheets that are crimped, pleated, assembled, or folded to form the channels. In some embodiments, the multiple longitudinally extending channels may be defined by multiple sheets that are crimped, pleated, assembled, or folded, i.e., two or more sheets that are brought into an overlay arrangement and then crimped, pleated, assembled, or folded as one.

[0183] One such additional aerosol 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.

[0184] One such aerosol cooling element preferably provides a low draw resistance to the passage of air through the additional cooling element. Preferably, the aerosol cooling element does not substantially affect the draw resistance of the aerosol-generating article. The aerosol cooling element preferably comprises a sheet material selected from the group consisting of metal foil, polymer sheet, and substantially non-porous 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.

[0185] The aerosol-generating article further comprises an upstream section at a location upstream of the aerosol-generating element. The upstream section may comprise one or more upstream elements. In some embodiments, the upstream section may comprise an upstream element located immediately upstream of the aerosol-generating element.

[0186] The aerosol-generating article of the present invention preferably comprises an upstream element upstream of and adjacent to the aerosol-generating element, 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, the upstream element may prevent direct physical contact with the upstream end of the susceptor element provided within the aerosol-generating element. This helps to prevent displacement or deformation of the susceptor element during handling or transport 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.

[0187] 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 information about the brand, flavor, content, or details of the aerosol-generating device with which the article is intended to be used.

[0188] The upstream element may be a porous plug element. Preferably, the porous plug element does not alter the resistance to withdrawal 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 by 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.

[0189] 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 over the cross section of the upstream element.

[0190] The porosity or permeability of the upstream element may be advantageously varied to provide a desired overall withdrawal resistance of the aerosol-generating article.

[0191] It is preferred that 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.

[0192] The RTD of the upstream element is preferably less than or equal to about 80 millimeters of H2O. More preferably, the RTD of the upstream element is less than or equal to about 60 millimeters of H2O. Even more preferably, the RTD of the upstream element is less than or equal to about 40 millimeters of H2O.

[0193] In some embodiments, the RTD of the upstream element is about 5 millimeters H2O to about 80 millimeters H2O, preferably about 10 millimeters H2O to about 80 millimeters H2O, more preferably about 15 millimeters H2O to about 80 millimeters H2O, and even more preferably about 20 millimeters H2O to about 80 millimeters H2O. In other embodiments, the RTD of the upstream element is about 5 millimeters H2O to about 60 millimeters H2O, preferably about 10 millimeters H2O to about 60 millimeters H2O, more preferably about 15 millimeters H2O to about 60 millimeters H2O, and even more preferably about 20 millimeters H2O to about 60 millimeters H2O. In further embodiments, the RTD of the upstream element is about 5 millimeters H2O to about 40 millimeters H2O, preferably about 10 millimeters H2O to about 40 millimeters H2O, more preferably about 15 millimeters H2O to about 40 millimeters H2O, and even more preferably about 20 millimeters H2O to about 40 millimeters H2O.

[0194] The upstream element may be formed from a material that is impermeable to air. The aerosol-generating article may be configured to allow air to flow into the rod of aerosol-generating substrate through suitable vent means provided in the wrapper.

[0195] 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.

[0196] The upstream element is preferably formed from a heat resistant material, for example the upstream element is preferably formed from a material that can withstand temperatures up to 350 degrees Celsius, thereby ensuring that the upstream element is not adversely affected by the heating means for heating the aerosol-generating substrate.

[0197] The upstream element preferably has a diameter approximately equal to the diameter of the aerosol-generating article.

[0198] 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 may be advantageously varied to provide a desired overall length of 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 may be increased to maintain the same overall length of the article.

[0199] 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, have no discernible symmetry.

[0200] 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, which provides structural rigidity to the upstream element.

[0201] The aerosol-generating article may have a length of from about 35 millimeters to about 100 millimeters.

[0202] The aerosol-generating article may have a length of from about 35 millimeters to about 100 millimeters.

[0203] Preferably, the overall length of an aerosol-generating article according to the invention is at least about 38 millimeters. More preferably, the overall length of an aerosol-generating article according to the invention is at least about 40 millimeters. Even more preferably, the overall length of an aerosol-generating article according to the invention is at least about 42 millimeters.

[0204] Preferably, the overall length of an aerosol-generating article according to the invention is 70 mm or less. More preferably, the overall length of an aerosol-generating article according to the invention is 60 mm or less. Even more preferably, the overall length of an aerosol-generating article according to the invention is 50 mm or less.

[0205] 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.

[0206] 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.

[0207] 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.

[0208] 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, 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, 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, more preferably about 7 mm to about 8 mm.

[0209] Preferably, an aerosol-generating article according to the invention comprises, in a linear continuous arrangement, an upstream element, an aerosol-generating substrate located immediately downstream of the upstream element, a support element located immediately downstream of the aerosol-generating element, a mouthpiece element located immediately downstream of the support element, and an outer wrapper surrounding the upstream element, the aerosol-generating element, the support element and the mouthpiece element.

[0210] More particularly, the aerosol generation element may abut the upstream element. The support element may abut the aerosol generation element. The aerosol cooling element may abut the support element. The mouthpiece element may abut the aerosol cooling element.

[0211] The aerosol-generating article has a substantially cylindrical shape and an outer diameter of about 7.25 millimeters.

[0212] The upstream element has a length of about 5 millimeters, the aerosol-generating element has a length of about 12 millimeters, the support element has a length of about 16 millimeters, and the mouthpiece element has a length of about 12 millimeters. The total length of the aerosol-generating article is therefore about 45 millimeters.

[0213] The upstream element is in the form of a plug of cellulose acetate encased in stiff plug wrap. The aerosol-generating article comprises an elongated susceptor disposed longitudinally substantially within and thermally coupled to the aerosol-generating substrate, the susceptor being in the form of a strip or blade and having a length substantially equal to the length of the aerosol-generating element and a thickness of about 60 micrometers.

[0214] The support element is in the form of a hollow cellulose acetate tube and has an inside diameter of about 1.9 millimeters, so that the peripheral wall thickness of the support element is about 2.675 millimeters.

[0215] The mouthpiece is in the form of a low density cellulose acetate filter segment.

[0216] The aerosol-generating substrate comprises homogenized tobacco.

[0217] The coating composition covers a majority of the exterior surface of the susceptor, and preferably substantially the entire exterior surface of the susceptor.

[0218] As described above, the aerosol-generating article according to the present invention can be produced at high speed by applying an appropriate method to existing equipment without requiring significant modification.

[0219] In one such method, in a first step, an aerosol-generating substrate is provided that includes a homogenized tobacco material that includes an aerosol former. In a second step, a protected coated susceptor is provided that includes a susceptor element coated with a coating composition that includes an aerosol former and isolated nicotine or a monobasic nicotine salt or both, and a protective layer applied over the coating composition. In a third step, the protective layer is removed to expose the coating composition and provide an unprotected coated susceptor. In a fourth step, the unprotected coated susceptor and the aerosol-generating substrate form an aerosol-generating element, such that the unprotected coated susceptor is disposed within the aerosol-generating element and configured to heat the homogenized tobacco material within the aerosol-generating substrate.

[0220] According to this method, it is advantageously possible to store the coated susceptor in a protected state, where the coating composition is effectively preserved. The protective layer can be removed only immediately prior to combining the coated susceptor with an aerosol-generating substrate to form an aerosol-generating element, so that the coating composition is advantageously protected from dust or other potential contaminants, for example, during storage or transportation. Furthermore, providing such a protective layer can prevent the layers of the coated susceptor from adhering to each other, for example, when the coated susceptor is supplied wound on a bobbin. The protective layer can be in the form of a metal foil, for example, an aluminum foil, and can be mechanically removed. In one embodiment, a continuous strip of protected coated susceptor can be fed through a foil removal unit, where the protective layer can be removed with a wedge or the like and wound up. The continuous strip of coated susceptor exiting the foil removal unit can be fed into a cone or funnel together with a sheet of homogenized tobacco material and a sheet of wrapper material to be joined into a continuous rod, which can then be cut into segments having a predetermined length.

[0221] In another such suitable method, in a first step, an aerosol-generating substrate is provided that includes a homogenized tobacco material that includes an aerosol former. In a second step, a susceptor element is provided. In a third step, the susceptor element is coated with a coating composition that includes an aerosol former and isolated nicotine or a monobasic nicotine salt, or both, to provide a coated susceptor. In a fourth step, the coated susceptor and the aerosol-generating substrate form an aerosol-generating element, such that the coated susceptor is disposed within the aerosol-generating element and configured to heat the homogenized tobacco material.

[0222] According to this method, the coating composition may be applied onto the outer surface of the susceptor element in the same enclosure in which the coated susceptor and the aerosol-generating substrate are combined. This may be accomplished by ejecting the coating composition onto the metal strip that forms the susceptor element. The coated susceptor may then be fed into a cone or funnel along with a sheet of homogenized tobacco material and a sheet of wrapper material to provide a continuous blank rod that may then be cut into segments having a predetermined length.

[0223] The present invention is defined in the claims. However, below is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of the other examples, embodiments, or aspects described herein.

[0224] Example 1. 1. An aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising: an aerosol-generating element comprising an aerosol-generating substrate, the aerosol-generating substrate comprising a homogenized tobacco material comprising an aerosol former; and a susceptor disposed within the aerosol-generating element and configured to heat the homogenized tobacco material, the susceptor being coated with a coating composition comprising at least 20 percent by weight of the aerosol former, the coating composition comprising isolated nicotine or a monobasic nicotine salt or both. Example 2. 2. The aerosol-generating article of example 1, wherein the susceptor is surrounded by homogenized tobacco material. Example 3. 3. The aerosol-generating article of example 1 or 2, wherein the susceptor is an elongated susceptor extending longitudinally through the aerosol-generating element. Example 4. An aerosol-generating article according to any one of Examples 1 to 3, wherein the homogenized tobacco material is provided as a collection of sheets of homogenized tobacco material. Example 5. 5. The aerosol-generating article of any one of Examples 1 to 4, wherein the coating composition comprises at least one gelling agent that forms a solid medium, the aerosol former is dispersed in the solid medium, and the isolated nicotine or the monobasic nicotine salt or both are dispersed in the aerosol former. Example 6. The aerosol-generating article of example 5, wherein the gelling agent comprises carboxymethylcellulose (CMC) or hydroxypropylmethylcellulose (HPMC) or both, and the aerosol former comprises glycerol. Example 7. The aerosol-generating article of any one of Examples 1-6, wherein the aerosol former comprises at least about 50 weight percent of the coating composition. Example 8. An aerosol-generating article according to any one of Examples 1-7, wherein the isolated nicotine or nicotine salt, or both, constitute at least about 0.5 weight percent of the coating composition. Example 9. An aerosol-generating article according to any one of Examples 1 to 8, wherein the coating composition forms a layer on the outer surface of the susceptor, the layer having a thickness of at least about 1 micrometer. Example 10. An aerosol-generating article according to any one of Examples 1 to 9, wherein the content of the aerosol formers in the coating composition accounts for at least about 0.25 percent of the total content of the aerosol formers in the aerosol-generating article. Example 11. An aerosol-generating article described in any one of Examples 1 to 10, comprising a downstream section located downstream of the aerosol-generating element, the downstream section comprising a support element located immediately downstream of the aerosol-generating element, the support element being longitudinally aligned with the aerosol-generating element and comprising a hollow tubular segment. Example 12. 12. The aerosol-generating article of example 11, comprising a mouthpiece element downstream of the support element. Example 13. An aerosol-generating article described in any one of Examples 1 to 12, comprising an upstream section at an upstream position of the aerosol-generating element, the upstream section being positioned immediately upstream of the aerosol-generating element and having a resistance to withdrawal (RTD) of less than about 80 millimeters HO. Example 14. 1. A method of manufacturing an aerosol-generating article for producing an inhalable aerosol upon heating, the method comprising: providing an aerosol-generating substrate comprising a homogenized tobacco material including an aerosol former; providing a protected coated susceptor, the protected coated susceptor comprising a susceptor element coated with a coating composition comprising an aerosol former and isolated nicotine or a monobasic nicotine salt or both, a protective layer being applied over the coating composition; removing the protective layer to expose the coating composition to provide an unprotected coated susceptor; and combining the unprotected coated susceptor and the aerosol-generating substrate to form an aerosol-generating element, such that the unprotected coated susceptor is disposed within the aerosol-generating element and configured to heat the homogenized tobacco material. Example 15. 1. A method of manufacturing an aerosol-generating article for producing an inhalable aerosol upon heating, the method comprising: providing an aerosol-generating substrate comprising a homogenized tobacco material comprising an aerosol former; providing a susceptor element; coating the susceptor element with a coating composition comprising the aerosol former and isolated nicotine or a monobasic nicotine salt or both to provide a coated susceptor; and combining the coated susceptor and the aerosol-generating substrate to form an aerosol-generating element, such that the coated susceptor is disposed within the aerosol-generating element and configured to heat the homogenized tobacco material.

[0225] The invention will now be further described with reference to the drawings of the accompanying drawings, in which: [Brief description of the drawings]

[0226] [Figure 1] FIG. 1 shows qualitative aerosol delivery over time during use of an aerosol-generating article according to the present invention. [Diagram 2] FIG. 2 shows a schematic cross-sectional side view of an aerosol-generating article according to the present invention. [Diagram 3] FIG. 3 shows a schematic perspective view of a coated susceptor of an aerosol-generating article according to an embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0227] The aerosol-generating article 10 shown in Figure 2 includes an aerosol-generating element 12 comprising an aerosol-generating substrate, and a downstream section 14 at a downstream position of the aerosol-generating element 12. In addition, the aerosol-generating article 10 includes an upstream section 16 at an upstream position of the aerosol-generating element 12. Thus, the aerosol-generating article 10 may extend from an upstream or distal end 18 to a downstream or oral end 20.

[0228] The aerosol-generating article has a total length of about 45 millimeters.

[0229] The downstream section 14 includes a support element 22 located immediately downstream of and in longitudinal alignment with the aerosol generation element 12. In the embodiment of Figure 2, the upstream end of the susceptor element 18 abuts the downstream end of the aerosol generation element 12.

[0230] The support element 22 includes a hollow tubular segment 24. The hollow tubular segment 24 is provided in the form of a hollow cylindrical tube made from cellulose acetate. The hollow tubular segment 24 defines an interior cavity 26 extending entirely from an upstream end 30 of the hollow tubular segment to a downstream end 32 of the hollow tubular segment 20. The interior cavity 26 is substantially empty, thus allowing substantially unrestricted airflow therealong. The hollow tubular segment 24, and consequently the support element 22, do not substantially contribute to the overall RTD of the aerosol-generating article 10. More specifically, the RTD of the first hollow tubular segment 24 (which is substantially the RTD of the support element 22) is substantially 0 millimeters H2O.

[0231] The hollow tubular segment 24 has a length of about 16 millimeters, an outer diameter of about 7.25 millimeters, and an inner diameter of about 1.9 millimeters. Thus, the peripheral wall thickness of the first hollow tubular segment 26 is about 2.67 millimeters.

[0232] In the embodiment of Figure 2, the downstream section 14 further comprises a mouthpiece element 42 downstream of the support element 22. More specifically, the mouthpiece element 42 is positioned immediately downstream of the support element 22. As shown in the diagram of Figure 2, the upstream end of the mouthpiece element 42 abuts the downstream end 40 of the support element 22.

[0233] Mouthpiece element 42 is provided in the form of a cylindrical plug of low density cellulose acetate.

[0234] 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.

[0235] The aerosol-generating element 12 comprises a sheet of homogenized tobacco material that is assembled to form a rod having an outer diameter of about 7.25 millimeters and a length of about 12 millimeters.

[0236] The aerosol-generating article 10 further comprises an elongated susceptor 44 within the aerosol-generating substrate 12. More specifically, the susceptor 44 is disposed substantially longitudinally within the aerosol-generating substrate 12 such that the susceptor 44 is generally parallel to the longitudinal direction of the aerosol-generating element 12. As shown in the diagram of Figure 2, the susceptor 44 is positioned at a radially central location within the rod and effectively extends along the longitudinal axis of the aerosol-generating element 12.

[0237] The susceptor 44 extends completely from the upstream end to the downstream end of the aerosol generating element 12. In practice, the susceptor 44 has substantially the same length as the aerosol generating element 12.

[0238] In the embodiment of FIG. 2, the susceptor 44 is provided in the form of a metal strip having a length of about 12 millimeters, a thickness of about 60 micrometers, and a width of about 4 millimeters.

[0239] The upstream section 16 includes an upstream element 46 located immediately upstream of the aerosol generation element 12, with the upstream element 46 being longitudinally aligned with the aerosol generation element 12. In the embodiment of Figure 1, the downstream end of the upstream element 46 abuts the upstream end of the aerosol generation element 12. This advantageously prevents the susceptor 44 from becoming dislodged. Furthermore, this can ensure that a consumer cannot accidentally come into contact with the heated susceptor 44 after use.

[0240] The upstream element 46 is provided in the form of a cylindrical plug of cellulose acetate surrounded by a rigid wrapper. The upstream element 46 has a length of about 5 millimeters. The RTD of the upstream element 46 is about 30 millimeters HO.

[0241] The susceptor 44 is shown in more detail in Figure 3. The outer surface of the metal strip is coated with a layer 48 of a coating composition, the layer 48 having a thickness of about 30 micrometers.

[0242] Examples of suitable coating compositions are shown in Table 1 below. [Table 1]

[0243] As shown in Figure 3, both the top surface 50 and the bottom surface 52 of the strip of susceptor 44 are coated with respective layers 54, 56 comprising the coating composition. Figure 3 further illustrates how the susceptor 44 is provided with protective layers 58, 60 applied over the layers 54, 56 comprising the coating composition according to one of the manufacturing methods described above.

[0244] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like should be understood in all cases as being modified by the term "about." Also, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically recited herein. Thus, in this context, the number A is understood as A ± 10% of A. Within this context, the number A may be considered to include numerical values ​​that are within the general standard error for the measurement of the property that the number A modifies. The number A may, in some instances used in the appended claims, deviate by the percentages recited above, provided that the amount by which A deviates does not materially affect the basic and novel properties of the claimed invention. Also, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically recited herein.

Claims

1. 1. An aerosol-generating article for generating an inhalable aerosol upon heating, said aerosol-generating article comprising: an aerosol-generating element comprising an aerosol-generating substrate comprising a homogenized tobacco material containing an aerosol former; and 1. An aerosol-generating article comprising: a susceptor disposed within the aerosol-generating element and configured to heat the homogenized tobacco material, the susceptor coated with a coating composition comprising at least 20 percent by weight of an aerosol former, the coating composition further comprising about 0.5 percent to about 10 percent by weight of tobacco-derived isolated nicotine or a monobasic nicotine salt, or both.

2. The aerosol-generating article of claim 1 , wherein the susceptor is surrounded by the homogenized tobacco material.

3. 3. The aerosol-generating article of claim 1 or 2, wherein the susceptor is an elongated susceptor extending longitudinally within the aerosol-generating element.

4. The aerosol-generating article of any one of claims 1 to 3, wherein the homogenized tobacco material is provided as an assembly of sheets of homogenized tobacco material.

5. 5. The aerosol-generating article of claim 1, wherein the coating composition comprises at least one gelling agent that forms a solid medium, the aerosol former is dispersed in the solid medium, and the isolated nicotine or monobasic nicotine salt or both are dispersed in the aerosol former.

6. 6. The aerosol-generating article of claim 5, wherein the gelling agent comprises carboxymethylcellulose (CMC) or hydroxypropylmethylcellulose (HPMC) or both, and the aerosol former comprises glycerol.

7. The aerosol-generating article of any one of claims 1 to 6, wherein the aerosol former comprises at least about 50 percent by weight of the coating composition.

8. 8. The aerosol-generating article of claim 1, wherein the coating composition forms a layer on the outer surface of the susceptor, the layer having a thickness of at least about 1 micrometer.

9. 9. The aerosol-generating article of claim 1, wherein the content of aerosol formers in the coating composition accounts for at least about 0.25 percent of the total content of aerosol formers in the aerosol-generating article.

10. 10. The aerosol-generating article of any one of claims 1 to 9, comprising a downstream section downstream of the aerosol generating element, the downstream section comprising a support element located immediately downstream of the aerosol generating element, the support element being longitudinally aligned with the aerosol generating element and comprising a hollow tubular segment.

11. The aerosol-generating article of claim 10 , comprising a mouthpiece element downstream of the support element.

12. 12. The aerosol-generating article of any one of claims 1 to 11, comprising an upstream section at an upstream position of the aerosol-generating element, the upstream section comprising an upstream element positioned immediately upstream of the aerosol-generating element and having a resistance to withdrawal (RTD) of less than about 80 millimeters HO.

13. 1. A method of making an aerosol-generating article for generating an inhalable aerosol upon heating, the method comprising: Providing an aerosol-generating substrate comprising a homogenized tobacco material with an aerosol former; providing a protected coated susceptor, the protected coated susceptor comprising a susceptor element coated with an aerosol former and a coating composition comprising about 0.5 weight percent to about 10 weight percent of tobacco-derived isolated nicotine or a monobasic nicotine salt or both, and a protective layer applied over the coating composition; removing said protective layer to expose said coating composition and provide an unprotected coated susceptor; combining the unprotected coated susceptor and the aerosol-generating substrate to form an aerosol-generating element, such that the unprotected coated susceptor is disposed within the aerosol-generating element and configured to heat the homogenized tobacco material.

14. 1. A method of making an aerosol-generating article for generating an inhalable aerosol upon heating, the method comprising: Providing an aerosol-generating substrate comprising a homogenized tobacco material with an aerosol former; Providing a susceptor element; coating a susceptor element with a coating composition comprising an aerosol former and about 0.5 weight percent to about 10 weight percent of tobacco-derived isolated nicotine or a monobasic nicotine salt, or both, to provide a coated susceptor; and combining the coated susceptor and the aerosol-generating substrate to form an aerosol-generating element, such that the coated susceptor is disposed within the aerosol-generating element and configured to heat the homogenized tobacco material.

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