Aerosol-forming substrate

Abstract

An aerosol-forming substrate (12, 512, 1020) comprising the following based on dry weight: X weight% non-expanded graphite; and Y weight% expanded graphite. The value of X divided by Y is at least 0.5. Additionally, an aerosol-generating article (10, 510, 1000), an aerosol-generating system (100, 200, 2000), and a method for manufacturing an aerosol-forming substrate are provided.

Description

Technology Field

[0001] The present disclosure relates to an aerosol-forming substrate. The present disclosure also relates to an aerosol-generating article, an aerosol-generating system, and a method for manufacturing an aerosol-forming substrate. Background Technology

[0002] A conventional aerosol generating system comprises an aerosol generating device and an aerosol generating article comprising an aerosol forming substrate. When in use, the aerosol generating device interacts with the aerosol generating article to heat the aerosol forming substrate and cause the aerosol forming substrate to release volatile compounds. These compounds are then cooled to form an aerosol that is inhaled by a user.

[0003] The disclosed aerosol-forming substrate typically has relatively low thermal conductivity. This may be undesirable, particularly in aerosol generation systems where a blade is inserted into the aerosol-forming substrate and heated to heat the substrate. This is because the low thermal conductivity of the aerosol-forming substrate can result in a relatively large temperature gradient within the substrate during use. This may mean that the portion of the aerosol-forming substrate located furthest from the blade does not reach high temperatures and, consequently, does not release as many volatile compounds as would be released if the aerosol-forming substrate had higher thermal conductivity. In other words, the low thermal conductivity of the aerosol-forming substrate can undesirably lead to low utilization efficiency. Such low utilization efficiency may result in insufficient extraction of flavor and nicotine, as well as waste of the aerosol-forming substrate material, or both.

[0004] Furthermore, the disclosed aerosol-forming substrate cannot typically be heated to an operating temperature by induction. This implies that a separate susceptor element is typically required for induction heating. This can lead to increased costs. Additionally, this can result in the same problems as previously mentioned. For example, if the induction-heated susceptor element is positioned in a central location within the aerosol-forming substrate, the portion of the substrate furthest from the susceptor element may not reach high temperatures and, consequently, may not release a significant amount of volatile compounds.

[0005] Attempts have been made to increase the thermal conductivity of aerosol-forming substrates. However, to date, these attempts have been inadequate in one or more aspects.

[0006] The object of the present invention is to provide an improved aerosol-forming substrate, for example, an aerosol-forming substrate having increased thermal conductivity, and an aerosol-forming substrate that can ideally be manufactured using conventional machinery.

[0007] An aerosol-forming substrate is provided. The aerosol-forming substrate may comprise X weight% of non-expanded graphite based on dry weight. The aerosol-forming substrate may comprise Y weight% of expanded graphite based on dry weight. The value obtained by dividing X by Y may be at least 0.5.

[0008] Accordingly, according to the first aspect of the present disclosure, an aerosol-forming substrate is provided comprising X weight% of non-expanded graphite based on dry weight. The aerosol-forming substrate also comprises Y weight% of expanded graphite based on dry weight. The value obtained by dividing X by Y is at least 0.5.

[0009] Surprisingly, including expanded graphite in the aerosol-forming substrate can improve the performance of the aerosol-forming substrate more than including the same amount of non-expanded graphite. In this context, performance may refer to the nicotine and glycerin yields from an aerosol-generating article containing the aerosol-forming substrate during 12 puffs. These improvements are indicated by the data in Table 1 below. To collect the data in Table 1, three different plugs of aerosol-forming substrates were manually manufactured and then tested for 12 puffs under Health Canada Intense (HCI) smoking conditions using FTIR spectroscopy. However, as will be understood by those skilled in the art, plugs of aerosol-forming substrates may be manufactured using other techniques, such as using a machine, and data may be collected using other tests.

[0010] Table 1:

[0011]

[0012] Without being bound by theory, it is believed that at least some of these performance improvements are a result of the fact that expanded graphite has a lower bulk density than non-expanded graphite. This means that, for a sheet of aerosol-forming substrate having a specific basis weight, an aerosol-forming substrate containing expanded graphite is thicker than an aerosol-forming substrate containing non-expanded graphite. This can advantageously result in a reduction in the number or size of air gaps within the aerosol-forming substrate itself or between the surfaces of the aerosol-forming substrate, or both, for example when the aerosol-forming substrate is in the form of a corrugated sheet. Since these air gaps can act as thermal insulators within the aerosol-forming substrate, reducing the number or average size of these air gaps, or both, can advantageously improve the thermal conductivity of the aerosol-forming substrate and thus increase the yield of nicotine and glycerin when the aerosol-forming substrate is heated.

[0013] However, using too much expanded graphite can make the manufacture of aerosol-forming substrates more difficult, especially when using conventional machinery. For example, an aerosol-forming substrate may be manufactured by a method comprising the steps of preparing a slurry containing expanded graphite, then mixing the slurry, then casting and drying the slurry. However, in this case, as the proportion of expanded graphite in the slurry increases, the viscosity of the slurry also increases. If the viscosity of the slurry is too high, it may be difficult to mix or cast the slurry, especially when using conventional machinery. Any reference to the viscosity of the slurry in this invention refers to dynamic viscosity, which can be measured at room temperature unless otherwise specified and can be measured using a commercially available Anton Paar MCR302 rheometer.

[0014] The inventors have creatively overcome this potential problem by including expanded graphite as well as non-expanded graphite in the substrate. Referring again to the method mentioned in the previous paragraph, the inventors surprisingly discovered that adding non-expanded graphite to the slurry can reduce the viscosity of the slurry. Thus, non-expanded graphite, which reduces the viscosity of the slurry, can be used to counteract expanded graphite, which increases the viscosity of the slurry. By maintaining the ratio of non-expanded graphite to expanded graphite in the slurry above a critical threshold, the viscosity of the slurry can be maintained at an acceptable level while still obtaining the performance improvement provided by the expanded graphite.

[0015] Optionally, the value of X divided by Y is at least 0.65, 0.8, 1, 1.2, or 1.4. Advantageously, as the value of X divided by Y increases, the aerosol-forming substrate may become easier to manufacture, particularly with conventional machinery. As previously mentioned, this may be because the viscosity of the slurry decreases as the ratio of non-expanded graphite to expanded graphite in the slurry for manufacturing the aerosol-forming substrate increases.

[0016] Optionally, the value of X divided by Y is 10, 8, 6, 4, or 2 or less. Advantageously, as the value of X divided by Y decreases, the performance of the aerosol-forming substrate is improved, approaching the performance of an aerosol-forming substrate having expanded graphite and not having non-expanded graphite. As previously mentioned, this may be at least partially due to the reduction of the air gap within the aerosol-forming substrate when proportionally more expanded graphite is present.

[0017] Optionally, the value of X divided by Y is 0.5 to 10, 0.5 to 8, 0.5 to 6, 0.5 to 4, or 0.5 to 2. Optionally, the value of X divided by Y is 0.65 to 10, 0.65 to 8, 0.65 to 6, 0.65 to 4, or 0.65 to 2. Optionally, the value of X divided by Y is 0.8 to 10, 0.8 to 8, 0.8 to 6, 0.8 to 4, or 0.8 to 2. Optionally, the value of X divided by Y is 1 to 10, 1 to 8, 1 to 6, 1 to 4, or 1 to 2. Optionally, the value of X divided by Y is 1.2 to 10, 1.2 to 8, 1.2 to 6, 1.2 to 4, or 1.2 to 2. Optionally, the value of X divided by Y is 1.4 to 10, 1.4 to 8, 1.4 to 6, 1.4 to 4, or 1.4 to 2. Advantageously, these ranges may provide an optimal compromise between manufacturability, which can be improved as the value of X divided by Y increases, and aerosol-forming substrate performance, which can be improved as the value of X divided by Y decreases.

[0018] As described above, the aerosol-forming substrate may comprise X weight% of non-expanded graphite based on dry weight. Optionally, X is at least 1, 2, 3, 4, or 5. It may be particularly preferable that X is at least 4. Advantageously, increasing X can improve the manufacturability of the aerosol-forming substrate, as described above.

[0019] Optionally, X is 50, 30, 20, 15, 12, or 10 or less. It may be particularly desirable for X to be 20 or less. Preferably, limiting the amount of non-expanded graphite in the aerosol-forming substrate can provide more room for other components such as expanded graphite, tobacco, fibers, binders, flavoring agents, etc.

[0020] Optionally, X is 1 to 50, 1 to 30, 1 to 20, 1 to 15, 1 to 12, or 1 to 10. Optionally, X is 2 to 50, 2 to 30, 2 to 20, 2 to 15, 2 to 12, or 2 to 10. Optionally, X is 2 to 30, 2 to 20, 2 to 15, 2 to 12, or 2 to 10. Optionally, X is 3 to 50, 3 to 30, 3 to 20, 3 to 15, 3 to 12, or 3 to 10. Optionally, X is 4 to 50, 4 to 30, 4 to 20, 4 to 15, 4 to 12, or 4 to 10. Optionally, X is 5 to 50, 5 to 30, 5 to 20, 5 to 15, 5 to 12, or 5 to 10. It may be particularly preferable that X is 4 to 20. Advantageously, these ranges may provide an optimal compromise between the manufacturability of the aerosol-forming substrate, which can be improved as X increases, and allowing a larger amount of other components of the aerosol-forming substrate, which can be improved as X decreases.

[0021] As described above, the aerosol-forming substrate may comprise expanded graphite in weight% Y based on dry weight. Optionally, Y is at least 1, 2, 3, or 4. It may be particularly preferable that Y is at least 2. Advantageously, increasing Y can improve the performance of the aerosol-forming substrate as described above.

[0022] Optionally, Y is 40, 20, 15, 10, 8, or 6 or less. It may be particularly desirable for Y to be 10 or less. Advantageously, limiting the amount of expanded graphite contained in the aerosol-forming substrate can improve the manufacturability of the aerosol-forming substrate and allow for a larger amount of other components such as tobacco, fibers, binders, flavoring agents, etc.

[0023] Optionally, Y is 1 to 40, 1 to 20, 1 to 15, 1 to 10, 1 to 8, or 1 to 6. Optionally, Y is 2 to 40, 2 to 20, 2 to 15, 2 to 10, 2 to 8, or 2 to 6. Optionally, Y is 3 to 40, 3 to 20, 3 to 15, 3 to 10, 3 to 8, or 3 to 6. Optionally, Y is 4 to 40, 4 to 20, 4 to 15, 4 to 10, 4 to 8, or 4 to 6. It may be particularly preferable that n is at least 2 to 10. Advantageously, these ranges can provide an optimal compromise between the performance of the aerosol-forming substrate, which can be improved as Y increases, and the manufacturability of the aerosol-forming substrate, which can be improved as Y decreases, and the extent to which a larger amount of other components can be allowed.

[0024] It may be preferable for X to be 2 to 50 and Y to be 2 to 40. It may be more preferable for X to be 2 to 30 and Y to be 2 to 20. It may be much more preferable for X to be 2 to 20 and Y to be 2 to 20. It may be even more preferable for X to be 4 to 20 and Y to be 2 to 10. It may be most preferable for X to be 4 to 15 and Y to be 2 to 8.

[0025] Optionally, X weight% non-expanded graphite comprises or consists of a plurality of non-expanded graphite particles. The term “non-expanded graphite particles” may refer to particles comprising non-expanded graphite, for example, at least 50, 75, 90, 95, or 98 weight% non-expanded graphite, or particles composed of non-expanded graphite, or particles composed of non-expanded graphite excluding trace amounts of impurities.

[0026] Optionally, Y weight% of expanded graphite comprises or consists of a plurality of expanded graphite particles. The term "expanded graphite particles" may refer to particles containing expanded graphite, for example, at least 50, 75, 90, 95, or 98 weight% of expanded graphite, or particles composed of expanded graphite, or particles composed of expanded graphite excluding trace impurities.

[0027] The particles may be spherical, but to avoid any doubt, the term "particle" does not mean spherical particles. Non-expanded graphite particles may comprise one or more of non-expanded graphite flakes, non-expanded graphite sheets, and non-expanded graphite fibers. Expanded graphite particles may comprise one or more of expanded graphite flakes, expanded graphite sheets, and expanded graphite fibers.

[0028] Optionally, one or both of the plurality of non-expanded graphite particles and the plurality of expanded graphite particles may have a particle size distribution. The particle size distribution may be characterized by volume D10, D50, and D90 particle sizes. The volume D10 particle size is defined such that 10% of the sum of the volumes of all particles corresponds to the sum of the volumes of particles having a particle size of volume D10 or less. Similarly, the volume D50 particle size is defined such that 50% of the sum of the volumes of all particles corresponds to the sum of the volumes of particles having a particle size of volume D50 or less. And, the volume D90 particle size is defined such that 90% of the sum of the volumes of all particles corresponds to the sum of the volumes of particles having a particle size of volume D90 or less.

[0029] Optionally, a plurality of non-expanded graphite particles have a particle size distribution having a volume D90 diameter of at least 0.1, 0.5, 1, 5, or 10 μm. Optionally, a plurality of non-expanded graphite particles have a particle size distribution having a volume D90 diameter of 500, 200, 100, 75, 50, or 35 μm or less. Optionally, a plurality of non-expanded graphite particles have a particle size distribution having a volume D90 diameter of 1 to 200 μm, preferably 5 to 100 μm, particularly preferably 10 to 75 μm, most preferably 35 to 75 μm.

[0030] Optionally, a plurality of non-expanded graphite particles have a particle size distribution having a volume D50 diameter of at least 0.1, 0.5, 1, 5, or 10 μm. Optionally, a plurality of non-expanded graphite particles have a particle size distribution having a volume D50 diameter of 500, 200, 100, 75, 50, or 35 μm or less. Optionally, a plurality of non-expanded graphite particles have a particle size distribution having a volume D50 diameter of 0.5 to 200 μm, preferably 1 to 100 μm, particularly preferably 2 to 75 μm, most preferably 5 to 50 μm.

[0031] Optionally, a plurality of non-expanding graphite particles have a particle size distribution having a volume D10 diameter of at least 0.1, 0.5, 1, or 5 μm. Optionally, a plurality of non-expanding graphite particles have a particle size distribution having a volume D10 diameter of 500, 200, 100, 75, 50, or 35 μm or less. Optionally, a plurality of non-expanding graphite particles have a particle size distribution having a volume D10 diameter of 0.1 to 100 μm, preferably 0.1 to 75 μm, particularly preferably 0.5 to 50 μm, most preferably 1 to 35 μm.

[0032] Optionally, a plurality of expanded graphite particles have a particle size distribution having a volume D90 diameter of at least 0.1, 0.5, 1, 5, or 10 μm. Optionally, a plurality of expanded graphite particles have a particle size distribution having a volume D90 diameter of 500, 200, 100, 75, 50, or 35 μm or less. Optionally, a plurality of expanded graphite particles have a particle size distribution having a volume D90 diameter of 1 to 200 μm, preferably 5 to 100 μm, particularly preferably 10 to 75 μm, most preferably 35 to 75 μm.

[0033] Optionally, a plurality of expanded graphite particles have a particle size distribution having a volume D50 diameter of at least 0.1, 0.5, 1, 5, or 10 μm. Optionally, a plurality of expanded graphite particles have a particle size distribution having a volume D50 diameter of 500, 200, 100, 75, 50, or 35 μm or less. Optionally, a plurality of expanded graphite particles have a particle size distribution having a volume D50 diameter of 0.5 to 200 μm, preferably 1 to 100 μm, particularly preferably 2 to 75 μm, most preferably 5 to 50 μm.

[0034] Optionally, a plurality of expanded graphite particles have a particle size distribution having a volume D10 diameter of at least 0.1, 0.5, 1, or 5 μm. Optionally, a plurality of expanded graphite particles have a particle size distribution having a volume D10 diameter of 500, 200, 100, 75, 50, or 35 μm or less. Optionally, a plurality of expanded graphite particles have a particle size distribution having a volume D10 diameter of 0.1 to 100 μm, preferably 0.1 to 75 μm, particularly preferably 0.5 to 50 μm, most preferably 1 to 35 μm.

[0035] Advantageously, the above range can provide an optimal compromise between increasing the thermal conductivity of the aerosol-forming substrate more significantly than that of small particles while reducing the available space for other components within the aerosol-forming substrate.

[0036] Optionally, a plurality of non-expanding graphite particles have a particle size distribution in which the volume D90 particle size is 50, 40, 30, 20, 10, or 5 times or less the volume D10 particle size. Optionally, a plurality of non-expanding graphite particles have a particle size distribution in which the volume D90 particle size is at least 1.5, 2, 3, 5, 10, or 20 times the volume D10 particle size.

[0037] Optionally, a plurality of expanded graphite particles have a particle size distribution in which the volume D90 particle size is 50, 40, 30, 20, 10, or 5 times or less the volume D10 particle size. Optionally, a plurality of expanded graphite particles have a particle size distribution in which the volume D90 particle size is at least 1.5, 2, 3, 5, 10, or 20 times the volume D10 particle size.

[0038] A compromise must be made regarding particle size distribution. For example, a narrower particle size distribution characterized by a smaller proportion between D90 and D10 particle sizes can advantageously provide more uniform thermal conductivity across the entire aerosol-forming substrate. This is because there is less variation in particle size at different locations within the substrate. This can advantageously allow for more efficient use of the aerosol-forming material across the entire aerosol-forming substrate. However, a stricter particle size distribution can disadvantageously be more difficult and costly to achieve. The aforementioned particle size distribution can provide an optimal compromise between these two factors.

[0039] Optionally, each of the plurality of non-expanding graphite particles has three mutually perpendicular dimensions, wherein the maximum dimension of the three dimensions is 10, 8, 5, 3, or 2 times or less than the minimum dimension of the three dimensions; and one or both of the second maximum dimension of the three dimensions is 10, 8, 5, 3, or 2 times or less. Optionally, each of the plurality of non-expanding graphite particles is substantially spherical.

[0040] Optionally, each of the plurality of expanded graphite particles has three mutually perpendicular dimensions, wherein the maximum dimension of the three dimensions is no more than 10, 8, 5, 3, or 2 times larger than one or both of the minimum dimension of the three dimensions and the second maximum dimension of the three dimensions. Optionally, each of the plurality of expanded graphite particles is substantially spherical.

[0041] Optionally, the plurality of non-expanded graphite particles comprises at least 10, 20, 50, 100, 200, 500, or 1,000 particles. Optionally, the plurality of expanded graphite particles comprises at least 10, 20, 50, 100, 200, 500, or 1,000 particles. Advantageously, the more particles there are, the more uniform the thermal conductivity of the aerosol-forming substrate can be.

[0042] Expanded graphite can have a density less than 0.2, 0.1, 0.05, or 0.01 times that of non-expanded graphite.

[0043] Expanded graphite is 2, 1.8, 1.5, 1.2, 1, 0.8, or 0.5, 0.2, 0.1, 0.05, 0.02 g / cm³ 3 It can have a density of less than 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 0.8, 1, 1.2, 1.5, or 1.8 g / cm³. 3It can have excess density. Expanded graphite is 0.01 to 3, 0.01 to 2, 0.01 to 1.8, 0.01 to 1.5, 0.01 to 1.2, 0.01 to 1, 0.01 to 0.8, 0.01 to 0.5, 0.02 to 3, 0.02 to 2, 0.02 to 1.8, 0.02 to 1.5, 0.02 to 1.2, 0.02 to 1, 0.02 to 0.8, 0.02 to 0.5, 0.01 to 3, 0.05 to 2, 0.05 to 1.8, 0.05 to 1.5, 0.05 to 1.2, 0.05 to 1, 0.05 to 0.8, 0.05 to 0.5g / cm 3 , 0.1 to 3, 0.1 to 2, 0.1 to 1.8, 0.1 to 1.5, 0.1 to 1.2, 0.1 to 1, 0.1 to 0.8, 0.1 to 0.5, 0.2 to 3, 0.2 to 2, 0.2 to 1.8, 0.2 to 1.5, 0.2 to 1.2, 0.2 to 1, 0.2 to 0.8, 0.2 to 0.5, 0.5 to 3, 0.5 to 2, 0.5 to 1.8, 0.5 to 1.5, 0.5 to 1.2, 0.5 to 1, 0.5 to 0.8, 0.8 to 3, 0.8 to 2, 0.8 to 1.8, 0.8 to 1.5, 0.8 to 1.2, 0.8 to 1 g / cm³ 3 It can have a density of.

[0044] Optionally, the substrate comprises at least one aerosol-forming agent. Optionally, the substrate comprises at least 5, 10, 20, 30, or 50 weight percent of at least one aerosol-forming agent based on dry weight. Optionally, the substrate comprises 95, 80, 50, or 30 weight percent or less of at least one aerosol-forming agent based on dry weight. Optionally, the substrate comprises at least one aerosol-forming agent in an amount of 5 to 80, 5 to 50, 5 to 30, 10 to 80, 10 to 50, 10 to 30, 20 to 80, 20 to 50, 20 to 30, or 30 to 80 weight percent based on dry weight. It may be particularly desirable for the substrate to comprise at least one aerosol-forming agent in an amount of 10 to 80, more preferably 10 to 50, based on dry weight.

[0045] Optionally, at least one aerosol-forming agent comprises or consists of one or more of polyhydric alcohols such as propylene glycol, polyethylene glycol, triethylene glycol, 1,3-butanediol, and glycerin; 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. Optionally, the aerosol-forming substrate comprises one or both of glycerin and propylene glycol.

[0046] Optionally, the substrate comprises fibers. Optionally, the substrate comprises 2, 5, or 10 weight percent of fibers based on dry weight. Optionally, the substrate comprises 20 or 10 weight percent or less of fibers based on dry weight. Optionally, the substrate comprises 2 to 20, 2 to 10, 5 to 20, 5 to 10, or 10 to 20 weight percent of fibers based on dry weight. It may be particularly preferable for the substrate to comprise 2 to 10 weight percent of fibers based on dry weight.

[0047] Optionally, the fiber is a cellulose fiber. Advantageously, cellulose fibers can increase the tensile strength of the substrate without excessive cost.

[0048] Optionally, each fiber has three mutually perpendicular dimensions, and the maximum of the three dimensions is at least 1.5, 2, 3, 5, 10, or 20 times larger than the minimum of the three dimensions. Optionally, each fiber has three mutually perpendicular dimensions, and the maximum of the three dimensions is at least 1.5, 2, 3, 5, 10, or 20 times larger than the second maximum of the three dimensions.

[0049] Optionally, the substrate comprises at least one binder. Optionally, the substrate comprises at least 1, 2, or 5 weight percent of at least one binder based on dry weight. Optionally, the substrate comprises at least 20, 15, 10, or 5 weight percent or less of at least one binder based on dry weight. Optionally, the substrate comprises at least one binder in 1 to 20, 2 to 20, 5 to 20, 1 to 15, 2 to 15, 5 to 15, 1 to 10, 2 to 10, 5 to 10, 1 to 5, or 2 to 5 weight percent based on dry weight. It may be particularly desirable for the substrate to comprise at least one binder in 1 to 20, more preferably 2 to 20, and most preferably 2 to 15 weight percent based on dry weight.

[0050] Suitable binders are well known in the art and include, but are not limited to, natural pectin such as fruit, citrus, or tobacco pectin; guar gum such as hydroxyethyl guar and hydroxypropyl guar; locust bean gum such as hydroxyethyl and hydroxypropyl locust bean gum; alginate; starch such as modified or derived starch; cellulose such as methyl, ethyl, ethylhydroxymethyl, and carboxymethyl cellulose; tamarind gum; dextran; pullon; konjac flour; xanthan gum, etc. It may be particularly preferable that the binder comprises or consists of one or more of carboxymethyl cellulose, hydroxypropyl cellulose, gum, or guar, e.g., guar gum. It may be particularly desirable that at least one binder comprises one or both of carboxymethyl cellulose and guar gum, or is composed of them.

[0051] Advantageously, carboxymethyl cellulose may have the additional advantage of reducing crusting of the aerosol-forming substrate when used in aerosol-generating articles.

[0052] Optionally, carboxymethyl cellulose includes sodium carboxymethyl cellulose. Advantageously, sodium carboxymethyl cellulose is carboxymethyl cellulose that can be particularly effective in preventing the crusting problems mentioned above.

[0053] Optionally, the material contains nicotine. If the material contains tobacco and the tobacco contains nicotine, the material may contain additional nicotine in addition to the nicotine of the tobacco.

[0054] Optionally, the substrate comprises at least 0.01, 0.1, 1, or 2 weight percent of nicotine based on dry weight. Optionally, the substrate comprises 5, 2, or 1 weight percent or less of nicotine based on dry weight. Optionally, the substrate comprises 0.01 to 5, 0.01 to 2, 0.01 to 1, 0.1 to 5, 0.1 to 2, 0.1 to 1, 1 to 5, 1 to 2, or 2 to 5 weight percent of nicotine based on dry weight. It may be particularly preferable for the substrate to comprise 0.1 to 2 weight percent of nicotine based on dry weight. These weight percent of nicotine may refer to the weight percent of nicotine in the entire substrate. Alternatively, if the substrate comprises tobacco and the tobacco comprises nicotine, these weight percent may refer to the weight percent of additional nicotine in addition to the nicotine in the tobacco.

[0055] Optionally, the substrate comprises at least one acid. Optionally, the substrate comprises at least 0.01, 1, 2, 3, or 4 weight percent of at least one acid based on dry weight. Optionally, the substrate comprises at least 5, 4, 3, 2, or 1 weight percent or less of at least one acid based on dry weight. Optionally, the substrate comprises at least one acid based on dry weight in an amount of 0.01 to 5, 1 to 5, 2 to 5, 3 to 5, 4 to 5, 0.01 to 4, 1 to 4, 2 to 4, 3 to 4, 0.01 to 3, 1 to 3, 2 to 3, 0.01 to 2, 1 to 2, or 0.01 to 1 weight percent. It may be particularly preferable that the substrate comprises at least one acid in an amount of 0.5 to 3 weight percent based on dry weight.

[0056] Optionally, at least one acid comprises or consists of one or more carboxylic acids. Optionally, at least one acid comprises or consists of one or more of fumaric acid, lactic acid, benzoic acid, and levulinic acid.

[0057] Optionally, the substrate comprises at least one plant. The at least one plant may be at least one non-tobacco plant. Optionally, the substrate comprises at least 0.01, 1, 2, 5, or 10 weight% of at least one plant based on dry weight. Optionally, the substrate comprises at least 50, 20, 10, or 5 weight% or less of at least one plant based on dry weight. Optionally, the substrate comprises at least one plant based on dry weight in an amount of 0.01 to 50, 1 to 50, 2 to 50, 5 to 50, 10 to 50, 0.01 to 20, 1 to 20, 2 to 20, 5 to 20, 10 to 20, 0.01 to 10, 1 to 10, 2 to 10, 5 to 10, 0.01 to 5, 1 to 5, or 2 to 5 weight%. Based on dry weight, it may be particularly preferable that the substrate contains at least one plant in an amount of 2 to 20 weight percent.

[0058] At least one non-tobacco plant may comprise or consist of any one or more of peppermint, star anise, lavender, clove, common sage, chamomile, rosemary, eucalyptus, ginger, dill seed, thyme, oregano, and cumin. Preferably, at least one non-tobacco plant may comprise or consist of any one or more of peppermint, star anise, lavender, clove, common sage, chamomile, and rosemary. Advantageously, at least one plant may impart desirable flavor characteristics to the substrate.

[0059] Optionally, at least a portion of at least one plant may be present in the substrate in the form of particles. These particles may be dispersed through an aerosol-forming substrate and, for example, may be substantially homogeneously dispersed.

[0060] Optionally, the substrate comprises at least one flavorant. Optionally, the substrate comprises at least 0.1, 1, 2, or 5 weight percent of at least one flavorant based on dry weight. Optionally, the substrate comprises at least 10, 5, 2, or 1 weight percent or less of at least one flavorant based on dry weight. Optionally, the substrate comprises at least one flavorant based on dry weight in an amount of 0.1 to 10, 1 to 10, 2 to 10, 5 to 10, 0.1 to 5, 1 to 5, 2 to 5, 0.1 to 2, 1 to 2, or 0.1 to 1 weight percent. It may be particularly preferable for the substrate to comprise at least one flavorant in an amount of 0.1 to 5 weight percent based on dry weight.

[0061] Optionally, the aerosol-forming substrate comprises at least one organic material such as tobacco. Optionally, at least one organic material comprises one or more of herb leaves, tobacco leaves, tobacco rib pieces, reconstituted tobacco, homogenized tobacco, tobacco powder, extruded tobacco, and puffed tobacco.

[0062] Optionally, the aerosol-forming substrate comprises at least 20, 30, 40, 50, or 60 weight percent of at least one organic material such as tobacco, based on dry weight. Optionally, the aerosol-forming substrate comprises 90, 80, or 70 weight percent or less of at least one organic material such as tobacco, based on dry weight. Optionally, the aerosol-forming substrate comprises 20 to 90, 20 to 80, 20 to 70, 30 to 90, 30 to 80, 30 to 70, 40 to 90, 40 to 80, 40 to 70, 50 to 90, 50 to 80, or 50 to 70 weight percent of at least one organic material such as tobacco, based on dry weight. It may be particularly desirable for the substrate to contain 40 to 90, more preferably 50 to 80, and most preferably 60 to 70 weight percent of at least one organic material, such as tobacco, based on dry weight.

[0063] Alternatively, the aerosol-forming substrate may be a low-tobacco or non-tobacco aerosol-forming substrate. Optionally, the aerosol-forming substrate contains less than 10 or 5 weight percent of tobacco on a dry weight basis. Optionally, the aerosol-forming substrate is a substantially tobacco-free aerosol-forming substrate.

[0064] Optionally, the aerosol-forming substrate has a moisture content of 1 to 20, or 3 to 15 weight%. This moisture content can be measured after equilibration for 48 hours at 20°C and 50% relative humidity. Optionally, the aerosol-forming substrate contains 1 to 20, or 3 to 15 weight% of water. The moisture or water content of the substrate can be measured using a titration method. The moisture or water content of the substrate can be measured using the Karl Fischer method.

[0065] In light of the foregoing, in a first set of particularly preferred embodiments of the present disclosure, for example, a first set of particularly preferred embodiments of the first aspect of the present disclosure, the substrate comprises: non-expanded graphite; expanded graphite; at least one organic material comprising or consisting of, preferably, tobacco; at least one binder comprising or consisting of, preferably, guar gum; at least one aerosol-forming agent comprising or consisting of, preferably, glycerin; and, preferably, a fiber comprising or consisting of, cellulose fiber.

[0066] In a first set of particularly preferred embodiments, the substrate preferably comprises at least 3 weight% and 20 weight% or less of non-expanded graphite based on dry weight, or both. The substrate preferably comprises 4 to 12 weight% of non-expanded graphite based on dry weight.

[0067] In a first set of particularly preferred embodiments, the substrate preferably comprises at least 2 weight% and 15 weight% or less of expanded graphite on a dry weight basis, or both. The substrate preferably comprises 3 to 10 weight% of expanded graphite on a dry weight basis.

[0068] In a first set of particularly preferred embodiments, the substrate preferably comprises at least 40% by weight and 90% by weight or less of at least one organic material based on dry weight, or both. The substrate preferably comprises 50 to 80% by weight of at least one organic material based on dry weight.

[0069] In a first set of particularly preferred embodiments, the substrate preferably comprises at least 0.5 weight% and 10 weight% or less of at least one binder based on dry weight, or both. The substrate preferably comprises 1 to 5 weight% of at least one binder based on dry weight.

[0070] In a first set of particularly preferred embodiments, the substrate preferably comprises at least 5% by weight and 50% by weight or less of at least one aerosol-forming agent based on dry weight, or both. Preferably, the substrate comprises 10 to 30% by weight of at least one aerosol-forming agent based on dry weight.

[0071] In the first set of particularly preferred embodiments, the substrate preferably comprises, on a dry weight basis, at least 1 weight percent and 15 weight percent or less of fibers, or both. The substrate preferably comprises 2 to 10 weight percent of fibers on a dry weight basis. Accordingly, according to the first set of particularly preferred embodiments, the substrate, on a dry weight basis,

[0072] 3 to 20 weight%, preferably 4 to 12 weight% of non-expanded graphite;

[0073] 2 to 15 weight%, preferably 3 to 10 weight% of expanded graphite;

[0074] At least one organic material comprising or composed of 40 to 90 weight%, preferably 50 to 80 weight%, preferably tobacco;

[0075] At least one binder comprising or composed of 0.5 to 10 weight%, preferably 1 to 5 weight%, of guar gum, preferably guar gum;

[0076] At least one aerosol-forming agent comprising or composed of 5 to 50 weight%, preferably 10 to 30 weight%, of glycerin; and

[0077] It may include fibers comprising 1 to 15 weight%, preferably 2 to 10 weight%, preferably cellulose fibers, or fibers composed thereof.

[0078] As will be understood by those skilled in the art after reading this disclosure, other features described herein may be applicable to particularly preferred embodiments of the first set. The method for manufacturing an aerosol-forming substrate described below may be a method for manufacturing an aerosol-forming substrate of a particularly preferred embodiment of the first set.

[0079] Optionally, the aerosol-forming substrate comprises hydroxypropylmethyl cellulose. Optionally, the aerosol-forming substrate comprises one or more cellulose-based reinforcing agents. Optionally, the aerosol-forming substrate comprises hydroxypropylmethyl cellulose and one or more cellulose-based reinforcing agents. Optionally, the aerosol-forming substrate comprises hydroxypropylmethyl cellulose and one or more cellulose-based reinforcing agents, and preferably does not contain tobacco or comprises one or more aerosol-forming agents. Thus, optionally, the aerosol-forming substrate comprises hydroxypropylmethyl cellulose and one or more cellulose-based reinforcing agents, is tobacco-free, and also comprises one or more aerosol-forming agents.

[0080] An aerosol-forming substrate comprising hydroxypropylmethyl cellulose and one or more cellulose-based reinforcing agents can have multiple advantages.

[0081] Including hydroxypropylmethyl cellulose in an aerosol-forming substrate can improve the manufacturing process of the aerosol-forming substrate. For example, hydroxypropylmethyl cellulose can reduce the viscosity of the slurry mixed when manufacturing the aerosol-forming substrate. The low-viscosity slurry can flow more easily than conventional slurries, and the low-viscosity slurry is easier to mix, deliver, and handle during the manufacturing process.

[0082] Including a cellulose-based reinforcing agent in an aerosol-forming substrate can increase the tensile strength of the aerosol-forming substrate. This can be particularly beneficial in the presence of hydroxypropylmethyl cellulose, as hydroxypropylmethyl cellulose can reduce the tensile strength of the substrate. An aerosol-forming substrate with higher tensile strength may be less likely to deteriorate or break, for example, during transport or during the manufacturing process.

[0083] Optionally, the aerosol-forming substrate comprises at least 0.5, 1, 5, 10, 15, or 20 weight% of hydroxypropylmethyl cellulose based on dry weight. Optionally, the aerosol-forming substrate comprises 50, 45, 40, 35, 30, 25, or 20 weight% or less of hydroxypropylmethyl cellulose based on dry weight. Optionally, the aerosol-forming substrate comprises 0.1 to 50, 1 to 50, 5 to 50, 10 to 50, 20 to 50, 0.1 to 40, 1 to 40, 5 to 40, 10 to 40, 20 to 40, 0.1 to 30, 1 to 30, 5 to 30, 10 to 30, 20 to 30, 0.1 to 20, 1 to 20, 5 to 20, 10 to 20, 0.1 to 10, 1 to 10, or 5 to 10 weight% of hydroxypropylmethyl cellulose based on dry weight. It may be preferable for the aerosol-forming substrate to contain 5 to 50, more preferably 10 to 50, and most preferably 20 to 50 weight% of hydroxypropylmethyl cellulose based on dry weight.

[0084] Optionally, the aerosol-forming substrate comprises at least 0.5, 1, 5, 10, 15, or 20 weight% of one or more cellulose-based reinforcing agents based on dry weight. Optionally, the aerosol-forming substrate comprises 50, 45, 40, 35, 30, 25, or 20 weight% or less of one or more cellulose-based reinforcing agents based on dry weight. Optionally, the aerosol-forming substrate comprises, based on dry weight, one or more cellulose-based reinforcing agents in an amount of 0.1 to 50, 1 to 50, 5 to 50, 10 to 50, 20 to 50, 0.1 to 40, 1 to 40, 5 to 40, 10 to 40, 20 to 40, 0.1 to 30, 1 to 30, 5 to 30, 10 to 30, 20 to 30, 0.1 to 20, 1 to 20, 5 to 20, or 10 to 20 weight%. It may be preferable for the aerosol-forming substrate to comprise one or more cellulose-based reinforcing agents in an amount of 5 to 50, more preferably 10 to 50, and most preferably 20 to 50 weight% based on dry weight.

[0085] One or more cellulose-based reinforcing agents may comprise or consist of one or more of cellulose fibers, microcrystalline cellulose, and cellulose powder. Advantageously, such cellulose-based reinforcing agents may be particularly effective in increasing the tensile strength of an aerosol-forming substrate.

[0086] In light of the foregoing, in a second set of particularly preferred embodiments of the present disclosure, such as a second set of particularly preferred embodiments of the first aspect of the present disclosure, the substrate comprises non-expanded graphite; expanded graphite; hydroxypropylmethyl cellulose; and at least one aerosol-forming agent, preferably glycerin.

[0087] A second set of particularly preferred embodiments may preferably contain less than 10 or 5 weight percent of tobacco based on dry weight. It may be particularly preferred that the substrate be tobacco-free.

[0088] This second set of particularly preferred embodiments may comprise any one or more or all of fibers, preferably cellulose fibers; microcrystalline cellulose; cellulose powder; sodium carboxymethyl cellulose; at least one binder or gelling agent, preferably agar; nicotine; and at least one acid such as a carboxylic acid, for example, lactic acid.

[0089] In a second set of particularly preferred embodiments, the substrate preferably comprises at least 3 weight% and 20 weight% or less of non-expanded graphite based on dry weight, or both. The substrate preferably comprises 4 to 12 weight% of non-expanded graphite based on dry weight.

[0090] In a second set of particularly preferred embodiments, the substrate preferably comprises at least 2 weight% and 15 weight% or less of expanded graphite on a dry weight basis, or both. The substrate preferably comprises 3 to 10 weight% of expanded graphite on a dry weight basis.

[0091] In a second set of particularly preferred embodiments, the substrate preferably comprises, on a dry weight basis, at least 5% by weight and 50% by weight or less of hydroxypropylmethyl cellulose, or both. The substrate preferably comprises 5 to 40% by weight of hydroxypropylmethyl cellulose on a dry weight basis.

[0092] In a second set of particularly preferred embodiments, the substrate preferably comprises at least 30% by weight and 80% by weight or less of at least one aerosol-forming agent based on dry weight, or both. Preferably, the substrate comprises 40 to 70% by weight of at least one aerosol-forming agent based on dry weight.

[0093] In a second set of particularly preferred embodiments in which the substrate comprises at least one binder or gelling agent, the substrate preferably comprises at least 2% by weight and 20% or less of at least one binder or gelling agent based on dry weight, or both. The substrate preferably comprises 2 to 10% by weight of at least one binder or gelling agent based on dry weight.

[0094] In a second set of particularly preferred embodiments in which the substrate comprises fibers, the substrate preferably comprises at least 2 weight% and 50 weight% or less of fibers on a dry weight basis, or both. The substrate preferably comprises 2 to 40 weight% of fibers on a dry weight basis.

[0095] In a second set of particularly preferred embodiments in which the substrate comprises microcrystalline cellulose, the substrate preferably comprises at least 2% by weight and 20% by weight or less of microcrystalline cellulose on a dry weight basis, or both. The substrate preferably comprises 2 to 10% by weight of microcrystalline cellulose on a dry weight basis.

[0096] In a second set of particularly preferred embodiments in which the substrate comprises sodium carboxymethyl cellulose, the substrate preferably comprises, on a dry weight basis, at least 2 weight% and 20 weight% or less of sodium carboxymethyl cellulose, or both. The substrate preferably comprises 2 to 10 weight% of sodium carboxymethyl cellulose on a dry weight basis.

[0097] In a second set of particularly preferred embodiments in which the substrate comprises cellulose powder, the substrate preferably comprises at least 2% by weight and 40% by weight or less of cellulose powder on a dry weight basis, or both. The substrate preferably comprises 5 to 30% by weight of cellulose powder on a dry weight basis.

[0098] In a second set of particularly preferred embodiments in which the substrate comprises nicotine, the substrate preferably comprises at least 0.5% by weight and 5% or less of nicotine based on dry weight, or both. Preferably, the substrate comprises 1 to 4% by weight of nicotine based on dry weight.

[0099] In a second set of particularly preferred embodiments in which the substrate comprises at least one acid, the substrate preferably comprises at least 1 weight% and 20 weight% or less of at least one acid based on dry weight, or both. The substrate preferably comprises 1 to 10 weight% of at least one acid based on dry weight.

[0100] Accordingly, according to a second set of particularly preferred embodiments, the substrate may comprise, on a dry weight basis, the following:

[0101] 3 to 20 weight%, preferably 4 to 12 weight% of non-expanded graphite;

[0102] 2 to 15 weight%, preferably 3 to 10 weight% of expanded graphite;

[0103] 5 to 50, preferably 5 to 40 weight% of hydroxypropylmethyl cellulose; and

[0104] 30 to 80 weight%, preferably 40 to 70 weight%, of at least one aerosol-forming agent.

[0105] In addition, according to a second set of particularly preferred embodiments, the substrate may comprise, on a dry weight basis, one or more or all of the following:

[0106] 2 to 20 weight%, preferably 2 to 10 weight%, of at least one binder or gelling agent;

[0107] 20 to 50 weight%, preferably 2 to 40 weight% of fibers;

[0108] 20 to 20 weight%, preferably 2 to 10 weight% of microcrystalline cellulose;

[0109] 2 to 20 weight%, preferably 2 to 10 weight% of sodium carboxymethyl cellulose;

[0110] 2 to 40 weight%, preferably 5 to 30 weight%, of cellulose powder

[0111] 0.5 to 5 weight%, preferably 1 to 4 weight% of nicotine; and

[0112] 1 to 20 weight%, preferably 1 to 10 weight% of at least one acid.

[0113] As will be understood by those skilled in the art after reading this disclosure, other features described herein may be applied to particularly preferred embodiments of the second set.

[0114] Optionally, in any one of the materials described herein, non-expanded graphite is substantially homogeneously distributed throughout the aerosol-forming substrate. Optionally, expanded graphite is substantially homogeneously distributed throughout the aerosol-forming substrate. Optionally, at least one aerosol-forming agent is substantially homogeneously distributed throughout the aerosol-forming substrate. Optionally, fibers are substantially homogeneously distributed throughout the aerosol-forming substrate. Optionally, at least one binder is substantially homogeneously distributed throughout the aerosol-forming substrate. Optionally, nicotine is substantially homogeneously distributed throughout the aerosol-forming substrate. Optionally, at least one acid is substantially homogeneously distributed throughout the aerosol-forming substrate. Optionally, at least one plant is substantially homogeneously distributed throughout the aerosol-forming substrate. Optionally, at least one flavoring agent is substantially homogeneously distributed throughout the aerosol-forming substrate. Optionally, at least one organic material is substantially homogeneously distributed throughout the aerosol-forming substrate. Optionally, hydroxypropylmethyl cellulose is substantially homogeneously distributed throughout the aerosol-forming substrate. Optionally, one or more cellulose-based reinforcing agents are substantially homogeneously distributed throughout the aerosol-forming substrate. Optionally, carboxymethyl cellulose is substantially homogeneously distributed throughout the aerosol-forming substrate.

[0115] Advantageously, a homogeneous distribution of the substrate components can cause the substrate to have more spatially uniform characteristics. For example, substantially homogeneously distributed non-expanding and expanded graphite particles can cause the substrate to have substantially uniform thermal conductivity. As another example, substantially homogeneously distributed binders or fibers can cause the substrate to have substantially uniform tensile strength.

[0116] Optionally, the aerosol-forming substrate comprises one or more of: a chip, powder particles, granules, pellets, pieces, spaghetti, strips, threads, ribbons, or sheets, or is in the form thereof.

[0117] Optionally, the aerosol-forming substrate comprises or is in the form of one or more sheets, e.g., corrugated sheets or rolled sheets. Optionally, the aerosol-forming substrate comprises or is in the form of multiple strips. Optionally, the aerosol-forming substrate is in the form of a tube.

[0118] Optionally, the sheet or each sheet is crimped. Optionally, the sheet or each sheet is crimped and pleated. The sheet or each sheet may be crimped and then pleated to form the or each crimped and pleated sheet.

[0119] Optionally, the above or each sheet or strip has a thickness of 5, 10, 20, 50, 100, 150, or 200 μm or more. Optionally, the above or each sheet or strip has a thickness of 2000, 1000, 500, 400, 300, or 250 μm or less. Optionally, the above or each sheet or strip has a thickness of 100 to 350, or 150 to 300 μm.

[0120] Optionally, the above or each sheet or strip has a width of at least 100, 200, 500, or 1000 μm. Optionally, the above or each sheet or strip has a width of 2000, 1000, 500, 400, 300, 250, or 200 μm or less. Optionally, the above or each sheet or strip has a width of 100 to 2000, or 500 to 1000, or 600 to 1000 μm.

[0121] Optionally, the above or each sheet or strip has a length of at least 100, 200, 500, 1000, 2000, or 3000 μm. Optionally, the above or each sheet or strip has a length of 6000, 5000, 3000, 2000, 1000, 500, or 200 μm or less. Optionally, the above or each sheet or strip has a length of 100 to 6000, or 500 to 5000, or 1000 to 4000 μm.

[0122] Optionally, the above or each sheet or strip has a basis weight of 20, 50, or 100 g / m2 or more. Optionally, the above or each sheet or strip has a basis weight of 300 g / m2 or less. Optionally, the above or each sheet or strip has a basis weight of 20 to 300, 50 to 250, or 100 to 250 g / m2.

[0123] Optionally, the above or each sheet or strip has a density of 0.1, 0.2, 0.3, or 0.5 g / m3 or greater. Optionally, the above or each sheet or strip has a density of 2, 1.5, 1.2, or 1 g / m3 or less. Optionally, the above or each sheet or strip has a density of 0.1 to 2, 0.2 to 2, 0.3 to 2, 0.3 to 1.5, or 0.3 to 1.2 g / m3.

[0124] If the substrate includes one or more corrugated sheets, the said or each corrugated sheet may have a width of about 1, 2, 5, 10, 25, 50, or 100 mm or more.

[0125] The aerosol-forming material may be in the form of a rod. In this way, a rod of the aerosol-forming material may be provided. The rod may be substantially cylindrical in shape, for example, a rectangular cylindrical shape.

[0126] The aerosol-forming substrate may include a susceptor element. The susceptor element may be distinguished from expanded graphite and non-expanded graphite. The susceptor element may be in contact with or located within the aerosol-forming substrate. The susceptor element may be an elongated susceptor element. The susceptor element may extend longitudinally within the rod of the aerosol-forming substrate. The susceptor element may be located at the radial center within the aerosol-forming substrate. The susceptor element may extend along the central longitudinal axis of the rod of the aerosol-forming substrate. The susceptor element may extend completely to the downstream end of the rod of the aerosol-forming substrate. The susceptor element may extend completely to the upstream end of the rod of the aerosol-forming substrate. The susceptor element may have substantially the same length as the rod of the aerosol-forming substrate. The susceptor element may extend completely from the upstream end to the downstream end of the rod of the aerosol-forming substrate. The susceptor element may be in the form of a pin, rod, strip, or blade. The susceptor element may have a length of 5 to 15, 6 to 12, or 8 to 10 mm. The susceptor element may have a width of 1 to 5 mm. The susceptor element may have a thickness of 0.01 to 2, 0.5 to 2, or 0.5 to 1 mm.

[0127] Alternatively, such susceptor elements may not be present within the aerosol-forming substrate or the load of the aerosol-forming substrate.

[0128] Optionally, the aerosol-forming substrate comprises a gel, e.g., a stable gel, or is in the form of a gel. Non-expanded graphite may be dispersed within the gel. Expanded graphite may be dispersed within the gel.

[0129] Optionally, the gel comprises a gelling agent, for example, a gelling agent that forms a solid medium. Optionally, the gel comprises an aerosol-forming agent such as glycerin. Optionally, the gel comprises nicotine. Optionally, the gel comprises a gelling agent that forms a solid medium, glycerin dispersed within the solid medium, and nicotine dispersed in the glycerin.

[0130] The gelling agent may comprise one or more of agar, xanthan gum, and low-acyl gellan. Optionally, the gel comprises 2.5 to 5 weight percent of the gelling agent based on dry weight. Optionally, the gel comprises 1 to 3, or 1.5 to 2.5 weight percent of nicotine based on dry weight. Optionally, the gel comprises 35 to 95 weight percent, preferably 50 to 95 weight percent, and more preferably 70 to 95 weight percent of an aerosol-forming agent such as glycerin based on dry weight. Optionally, the gel comprises less than 22 weight percent of water. Optionally, the gel comprises an acid such as a carboxylic acid, e.g., levulinic acid. Optionally, the gel comprises a divalent cation such as calcium ions.

[0131] Additionally, an aerosol generating article comprising an aerosol forming substrate is provided. The aerosol forming substrate may be an aerosol forming substrate according to the first aspect.

[0132] Accordingly, according to the second aspect of the present disclosure, an aerosol generating article comprising an aerosol forming substrate according to the first aspect is provided.

[0133] Optionally, the article may be in the form of a rod. Optionally, the article comprises a plurality of components including an aerosol-forming substrate assembled within a wrapper or casing.

[0134] Optionally, the aerosol generating article comprises a front plug. Optionally, the aerosol generating article comprises a first hollow tube, e.g., a first hollow acetate tube. Optionally, the aerosol generating article comprises a second hollow tube, e.g., a second hollow acetate tube. Optionally, the second hollow tube comprises one or more ventilation holes. Optionally, the aerosol generating article comprises a mouth plug filter. Optionally, the aerosol generating article comprises a wrapper, e.g., a paper wrapper.

[0135] Optionally, a foreplug is positioned at the upstream end of the article. Optionally, an aerosol-forming material is positioned downstream of the foreplug. Optionally, a first hollow tube is positioned downstream of the aerosol-forming material. Optionally, a second hollow tube is positioned downstream of the first hollow tube. Optionally, a mouth plug filter is positioned downstream of one or both of the first and second hollow tubes. Optionally, a mouth plug filter is positioned at the downstream end of the article. Optionally, the downstream end of the article, which may be referred to as the mouth end of the article, may be configured to be inserted into the user's mouth. The user may inhale, for example, directly from the mouth end of the article.

[0136] Optionally, the front plug, the aerosol-forming substrate, one or both of the first hollow tube and the second hollow tube, and the mouse plug filter are surrounded by a wrapper, e.g., a paper wrapper.

[0137] One or more of the front plug, aerosol forming material, first hollow tube, second hollow tube, and mouth plug filter may be substantially cylindrical, for example, in a vertical cylindrical shape.

[0138] An aerosol generating system comprising an aerosol generating article is also provided. The aerosol generating article may be an aerosol generating article according to the second aspect.

[0139] Accordingly, according to a third aspect of the present disclosure, an aerosol generating system comprising an aerosol generating article and an aerosol generating device is provided. The aerosol generating article is an aerosol generating article according to a second aspect.

[0140] Optionally, the device includes an inductor configured to inductively heat one or both of the non-expanding graphite and the expanding graphite of the article during use, for example, the substrate of the article.

[0141] Optionally, the device includes an electric resistance heating element configured to heat an article, for example, the substrate of the article, during use.

[0142] A method for forming an aerosol-forming substrate is also provided. The aerosol-forming substrate may be an aerosol-forming substrate according to the first aspect. The aerosol-forming substrate may be an aerosol-forming substrate of the first set of particularly preferred embodiments described above. The method may include the step of forming a slurry. The method may include the step of casting the slurry. The method may include the step of drying the slurry. The method may include the step of drying the slurry after casting it. The method may include the step of drying the slurry after casting it to form an aerosol-forming substrate or a precursor formed into an aerosol-forming substrate.

[0143] Accordingly, according to the fourth aspect of the present disclosure, a method for forming an aerosol-forming substrate according to the first aspect is provided. The method comprises the step of forming a slurry. The method comprises the step of casting and drying the slurry to form a precursor for forming an aerosol-forming substrate or an aerosol-forming substrate.

[0144] The aerosol-forming substrate may be the aerosol-forming substrate of the first set of particularly preferred embodiments described above.

[0145] The slurry may contain non-expanded graphite. The slurry may contain expanded graphite.

[0146] Optionally, the method comprises the step of forming a slurry comprising any one or more of water, tobacco, acid, nicotine, an aerosol forming agent, a fiber, a binder, hydroxypropylmethyl cellulose, one or more cellulose-based reinforcing agents, carboxymethyl cellulose, optionally non-expanded graphite in the form of non-expanded graphite particles, and optionally expanded graphite in the form of expanded graphite particles.

[0147] Optionally, the slurry contains water. Optionally, the slurry contains 20 to 90, 30 to 90, 40 to 90, 40 to 85, 50 to 80, 60 to 80, or 60 to 75 weight percent of water.

[0148] Optionally, the slurry comprises, on a dry weight basis, 0.5 X to 1.5 X weight% of non-expanded graphite, for example, about X weight% of expanded graphite. Optionally, the slurry comprises, on a dry weight basis, 0.5 Y to 1.5 Y weight% of expanded graphite, for example, about Y weight% of expanded graphite.

[0149] Optionally, the step of forming a slurry includes the step of forming a first mixture. The first mixture may include an aerosol-forming agent. The first mixture may include fibers. The first mixture may include water. The first mixture may include an acid. The first mixture may include nicotine.

[0150] The step of forming a slurry may include the step of forming a second mixture. The second mixture may include non-expanded graphite particles. The second mixture may include expanded graphite particles. The second mixture may include a binder.

[0151] The step of forming a slurry may include the step of adding a second mixture to a first mixture to form a combined mixture.

[0152] Accordingly, the step of forming a slurry may include the step of forming a first mixture; the step of forming a second mixture; and the step of adding the second mixture to the first mixture to form a combined mixture. The combined mixture may subsequently be formed into a slurry, for example, by mixing the combined mixture.

[0153] Optionally, the step of casting the slurry includes the step of casting the slurry onto a flat support, for example, a flat support made of steel.

[0154] Optionally, after casting the slurry and before drying the slurry, the method includes the step of setting the thickness of the slurry, for example, setting the thickness of the slurry to 100 to 1200, 200 to 1000, 300 to 900, 500 to 700 μm, for example, about 600 μm.

[0155] Optionally, the step of drying the slurry includes providing a flow of a gas, such as air, over or through the slurry. Optionally, the gas flow is heated. Optionally, the gas flow is heated to a temperature of 50 to 200, 100 to 160, or 120 to 140°C. Optionally, the gas flow is provided for 1 to 10 minutes or 2 to 5 minutes. Optionally, the step of drying the slurry includes drying the slurry until the slurry has a moisture content of 1 to 20, 2 to 15, 2 to 10, or 3 to 7 weight%.

[0156] Optionally, drying the slurry forms a precursor that forms an aerosol-forming substrate, and the precursor is a sheet of aerosol-forming material. Optionally, the method includes the step of cutting the sheet of aerosol-forming material.

[0157] As will be understood by those skilled in the art who read this disclosure, features described herein in relation to one aspect may be applicable to any other aspect. For example, features described in relation to a combined aerosol-forming substrate of a second aspect, or in relation to a first-second material of a combined aerosol-forming substrate of a second aspect, may be applied to an aerosol-forming substrate of a first aspect, and vice versa.

[0158] As used herein, the term “aerosol-forming substrate” may refer to a substrate capable of releasing an aerosol or a volatile compound capable of forming an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. The aerosol-forming substrate may comprise an aerosol-forming material. The aerosol-forming substrate may be adsorbed, coated, impregnated, or otherwise loaded onto a carrier or support. For convenience, the aerosol-forming substrate may be part of an aerosol-generating article or a smoking article.

[0159] As used herein, the term "nicotine" may refer to nicotine and nicotine derivatives such as free base nicotine, nicotine salts, etc.

[0160] As used herein, the term "non-expanded graphite" may refer to natural graphite or synthetic graphite. Non-expanded graphite may have carbon layers in which no elements or compounds are inserted into the spaces between the carbon layers.

[0161] Non-expanding graphite particles suitable for use as described herein are commercially available. For example, suitable non-expanding graphite particles are Graphit Kropfm It contains FP 99.5 L (>99.5% purity) natural graphite particles from hl GmbH, AMG Graphite GK. These particles typically have a carbon content of 99.7%, and when measured using laser diffraction with a Sympatec HELOS laser diffraction sensor, the particle size of volume D10 is 7 μm, the particle size of volume D50 is 21 μm, and the particle size of volume D90 is 55 μm.

[0162] As used herein, the term “expanded graphite” may refer to a modified graphite material or a material having a graphite-like structure. Expanded graphite may have carbon layers (e.g., similar to graphite) with an average spacing between carbon layers that is, for example, greater than the average spacing found between carbon layers in non-expanded graphite, for example, at least 2, 5, or 10 times greater. Expanded graphite may have carbon layers (e.g., similar to graphite) with an average spacing between carbon layers that is, for example, greater than the average spacing found between carbon layers in natural graphite, for example, at least 2, 5, or 10 times greater than the average spacing found between carbon layers in natural graphite. In some situations, non-expanded graphite may be heated to form expanded graphite. Expanded graphite may have carbon layers having elements or compounds inserted into the spaces between the carbon layers.

[0163] Expanded graphite particles suitable for use as described herein are commercially available. For example, suitable expanded graphite particles are Graphit Kropfm It includes SC 20 OS (>99% purity) expanded graphite particles from hl GmbH, AMG Graphite GK. These particles typically have a carbon content of 99.1%, and when measured using laser diffraction with a Sympatec HELOS laser diffraction sensor, the particle size of volume D10 is 6.5 μm, the particle size of volume D50 is 20 μm, and the particle size of volume D90 is 56 μm.

[0164] As used herein, the term "particle size" may refer to a single dimension and may be used to characterize the size of a given particle. The dimension may be the diameter of a spherical particle that occupies the same volume as the given particle at the same density as the given particle. All particle sizes and particle size distributions described herein can be obtained using standard laser diffraction techniques. Particle sizes and particle size distributions as described herein can be obtained using commercially available sensors, for example, Sympatec HELOS laser diffraction sensors.

[0165] As used herein, unless otherwise specified, the term "density" may be used to refer to true density. Thus, unless otherwise specified, the density of a powder or a plurality of particles may refer to the true density of the powder or a plurality of particles (not the bulk density of the powder or a plurality of particles, which can vary significantly depending on how the powder or a plurality of particles are handled). Measurement of true density can be performed using a number of standard methods, which are often based on Archimedes' principle. The most widely used method, when used to measure the true density of a powder, involves placing the powder inside a container of known volume (a pycnometer) and weighing it. Then, the pycnometer is filled with a fluid of known density in which the powder does not dissolve. The volume of the powder is determined by the difference between the volume indicated by the pycnometer and the volume of the added liquid (i.e., the volume of displaced air).

[0166] As used herein, the term "aerosol generating article" may refer to an article capable of generating or releasing an aerosol when heated, for example.

[0167] As used herein, the term “longitudinal” may refer to a direction extending between the downstream or proximal end and the upstream or distal end of a component, such as an aerosol-forming substrate or an aerosol-generating article.

[0168] As used herein, the term "transverse direction" may refer to a direction perpendicular to the longitudinal direction.

[0169] As used herein, the term "aerosol generating device" may refer to a device used in conjunction with an aerosol generating article to enable the generation or release of an aerosol from an aerosol generating article.

[0170] As used herein, the term “corrugated sheet” may refer to, for example, a sheet of an aerosol-forming substrate or an aerosol-generating article that is wavy, folded, or otherwise compressed or shrunken substantially transversely to the longitudinal axis of the aerosol-forming substrate or the aerosol-generating article.

[0171] As used herein, the term “sheet” may refer to a generally flat laminar element having a width and length substantially greater than its thickness by at least 2, 3, 5, 10, 20, or 50 times.

[0172] As used herein, the term “strip” may refer to a generally flat thin layer element having one or both of a width substantially greater than its thickness and a length substantially greater than its thickness. The width of the strip may be greater than its thickness, for example, at least 2, 3, 5, or 10 times its thickness. The length of the strip may be greater than its width, for example, at least 2, 3, 5, or 10 times its width.

[0173] As used herein, the term "aerosol-forming agent" may refer to any suitable known compound or mixture of compounds that facilitates the formation of an aerosol upon use. The aerosol may be a dense and stable aerosol. The aerosol may be substantially resistant to thermal decomposition at the operating temperature of the aerosol-forming substrate or the aerosol-generating article.

[0174] As used herein, the term "aerosol cooling element" refers to a component of an aerosol generating article located downstream of an aerosol forming substrate such that, upon use, the aerosol formed by a volatile compound released from the aerosol forming substrate passes through the aerosol cooling element and is cooled by it before being inhaled by a consumer.

[0175] As used herein, the term "rod" may refer to an element that is generally cylindrical, e.g., vertical cylinder, having a substantially circular, oval, or elliptical cross-section.

[0176] As used herein, the term “crimped” may refer to a sheet having one or more ridges or creases. The ridges or creases may be substantially parallel. When present within a component of an aerosol-generating article, the ridges or creases may extend longitudinally with respect to the aerosol-generating article.

[0177] As used herein, the terms “stable gel phase” or “stable gel” may refer 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 while varying relative humidity from about 10% to about 60%. For example, a stable gel can substantially maintain its shape and mass when exposed to standard temperature and pressure while varying relative humidity from about 10% to about 60%.

[0178] The present invention is defined in the claims. However, a non-limiting, non-comprehensive list of embodiments is provided below. Any one or more features of these embodiments may be combined with any one or more features of other embodiments, embodiments, or aspects described herein.

[0179] Ex1. As an aerosol-forming substrate, based on dry weight,

[0180] X weight% non-expanding graphite; and

[0181] Contains Y weight% expanded graphite,

[0182] Here, the value of X divided by Y is at least 0.5.

[0183] Ex2. An aerosol-forming substrate in Example Ex1, wherein the value of X divided by Y is at least 0.65, 0.8, 1, 1.2, or 1.4.

[0184] Ex3. An aerosol-forming substrate, wherein in any one of the previous embodiments, the value of X divided by Y is 10, 8, 6, 4, or 2 or less.

[0185] Ex4. An aerosol-forming substrate, wherein in any one of the previous embodiments, the value of X divided by Y is 0.5 to 10, 0.5 to 8, 0.5 to 6, 0.5 to 4, or 0.5 to 2.

[0186] Ex5. An aerosol-forming substrate, wherein in any one of the previous embodiments, the value of X divided by Y is 0.65 to 10, 0.65 to 8, 0.65 to 6, 0.65 to 4, or 0.65 to 2.

[0187] Ex6. An aerosol-forming substrate, wherein in any one of the previous embodiments, the value of X divided by Y is 0.8 to 10, 0.8 to 8, 0.8 to 6, 0.8 to 4, or 0.8 to 2.

[0188] Ex7. An aerosol-forming substrate, wherein in any one of the previous embodiments, the value of X divided by Y is 1 to 10, 1 to 8, 1 to 6, 1 to 4, or 1 to 2.

[0189] Ex8. An aerosol generating substrate, wherein in any one of the previous embodiments, the value of X divided by Y is 1.2 to 10, 1.2 to 8, 1.2 to 6, 1.2 to 4, or 1.2 to 2.

[0190] Ex9. An aerosol-forming substrate, wherein in any one of the previous embodiments, the value of X divided by Y is 1.4 to 10, 1.4 to 8, 1.4 to 6, 1.4 to 4, or 1.4 to 2.

[0191] Ex10. An aerosol-forming substrate, wherein X is at least 1, 2, 3, 4, or 5 in any one of the previous embodiments.

[0192] Ex11. An aerosol-forming substrate, wherein in any one of the previous embodiments, X is 30, 20, 15, 12, or 10 or less.

[0193] Ex12. In any one of the previous embodiments, X is 1 to 30, 1 to 20, 1 to 15, 1 to 12, or 1 to 10, an aerosol-forming substrate.

[0194] Ex13. In any one of the previous embodiments, X is an aerosol-forming substrate, wherein X is 2 to 30, 2 to 20, 2 to 15, 2 to 12, or 2 to 10.

[0195] Ex14. In any one of the previous embodiments, X is an aerosol-forming substrate, wherein X is 2 to 30, 2 to 20, 2 to 15, 2 to 12, or 2 to 10.

[0196] Ex15. In any one of the previous embodiments, X is an aerosol-forming substrate, wherein X is 3 to 30, 3 to 20, 3 to 15, 3 to 12, or 3 to 10.

[0197] Ex16. In any one of the previous embodiments, X is an aerosol-forming substrate of 4 to 30, 4 to 20, 4 to 15, 4 to 12, or 4 to 10.

[0198] Ex17. In any one of the previous embodiments, the aerosol-forming substrate is X, which is 5 to 30, 5 to 20, 5 to 15, 5 to 12, or 5 to 10.

[0199] Ex18. In any one of the previous embodiments, the aerosol-forming substrate, wherein Y is at least 1, 2, 3, or 4.

[0200] Ex19. An aerosol-forming substrate, wherein in any one of the previous embodiments, Y is 20, 15, 10, 8, or 6 or less.

[0201] Ex20. In any one of the previous embodiments, the aerosol-forming substrate, wherein Y is 1 to 20, 1 to 15, 1 to 10, 1 to 8, or 1 to 6.

[0202] Ex21. In any one of the previous embodiments, the aerosol-forming substrate, wherein Y is 2 to 20, 2 to 15, 2 to 10, 2 to 8, or 2 to 6.

[0203] Ex22. In any one of the previous embodiments, the aerosol-forming substrate, wherein Y is 3 to 20, 3 to 15, 3 to 10, 3 to 8, or 3 to 6.

[0204] Ex23. In any one of the previous embodiments, the aerosol-forming substrate, wherein Y is 4 to 20, 4 to 15, 4 to 10, 4 to 8, or 4 to 6.

[0205] Ex24. In any one of the previous embodiments,

[0206] X is 2 to 50 and Y is 2 to 40; or

[0207] X is 2 to 30 and Y is 2 to 20; or

[0208] X is 2 to 20 and Y is 2 to 20; or

[0209] X is 4 to 20 and Y is 2 to 10; or

[0210] An aerosol-forming substrate in which X is 4 to 15 and Y is 2 to 8.

[0211] Ex25. In any one of the prior embodiments, the X weight% non-expanded graphite comprises or consists of a plurality of non-expanded graphite particles; and the Y weight% expanded graphite comprises or consists of a plurality of expanded graphite particles, an aerosol-forming substrate.

[0212] Ex26. In any one of the previous embodiments,

[0213] The above X weight% non-expanding graphite comprises or is composed of a plurality of non-expanding graphite particles;

[0214] The above Y weight% expanded graphite comprises or is composed of a plurality of expanded graphite particles, an aerosol-forming substrate.

[0215] Ex27. An aerosol-forming substrate, wherein, in Example Ex25 or Ex26, the plurality of non-expanding graphite particles have a particle size distribution having a volume D90 diameter of 100 or 75 μm or less, preferably the volume D90 diameter is 10 to 100 μm or 35 to 75 μm, for example, the volume D90 diameter is about 55 μm.

[0216] Ex28. An aerosol-forming substrate, wherein, in Example Ex25 or Ex26, the plurality of expanded graphite particles have a particle size distribution having a volume D90 diameter of 100 or 75 μm or less, preferably the volume D90 diameter is 10 to 100 μm or 35 to 75 μm, for example, the volume D90 diameter is about 55 μm.

[0217] Ex29. An aerosol generating article comprising an aerosol-forming substrate according to any one of the previous embodiments.

[0218] Ex30. In Example Ex29, the aerosol-generating article is in the form of a corrugated sheet, wherein the aerosol-forming substrate is an aerosol-generating article.

[0219] Ex31. An aerosol generating system comprising an aerosol generating article and an aerosol generating device according to Example EX29 or EX30.

[0220] Ex32. In Example Ex31, the device comprises an inductor configured to inductively heat one or both of the non-expanded graphite and expanded graphite of the article, for example, the substrate of the article, during use, an aerosol generating system.

[0221] Ex33. A method for forming an aerosol-forming substrate according to any one of Examples Ex1 to Ex28, wherein the method comprises:

[0222] A step of forming a slurry comprising the above-mentioned non-expanded graphite and the above-mentioned expanded graphite;

[0223] A method comprising the step of casting and drying the above slurry to form the aerosol-forming substrate or the precursor formed into the aerosol-forming substrate. Brief explanation of the drawing

[0224] Examples will be further described with reference to the drawings. FIG. 1 shows a schematic cross-sectional view of a first embodiment of an aerosol generating article. FIG. 2 shows a schematic cross-sectional view of a first embodiment of an aerosol generation system including an aerosol generating device. FIG. 3 shows a schematic cross-sectional view of a second embodiment of an aerosol generating system including an aerosol generating device. FIG. 4 shows a schematic cross-sectional view of a second embodiment of an aerosol generating article. FIG. 5 illustrates an example of an aerosol generating article containing an aerosol-forming substrate as described herein. FIG. 6 shows an example of an aerosol generating system including the aerosol generating article and aerosol generating device shown in FIG. 5. Specific details for implementing the invention

[0225] FIG. 1 shows a schematic cross-sectional view of a first embodiment of an aerosol generating article (10).

[0226] The aerosol generating article (10) comprises a rod (12) of an aerosol forming material, a downstream section (14) located downstream of the rod (12), and an upstream section (16) located upstream of the rod (12). The aerosol generating article (10) extends from an upstream or distal end (18) to a downstream or proximal or mouse end (20). The aerosol generating article has a total length of about 45 mm.

[0227] The downstream section (14) includes a support element (22) located immediately downstream of the rod (12) of the aerosol-forming material, and the support element (22) is aligned longitudinally with the rod (12). The upstream end of the support element (22) borders the downstream end of the rod (12). The downstream section (14) further includes an aerosol cooling element (24) located immediately downstream of the support element (22), and the aerosol cooling element (24) is aligned longitudinally with the rod (12) and the support element (22). The upstream end of the aerosol cooling element (24) borders the downstream end of the support element (22). The support element (22) and the aerosol cooling element (24) together define an intermediate hollow section (50) of the aerosol-generating article (10).

[0228] The support element (22) includes a first hollow tubular segment (26). The first hollow tubular segment (26) is provided in the form of a hollow cylindrical tube made of cellulose acetate. The first hollow tubular segment (26) defines an internal cavity (28) that extends completely from the upstream end (30) of the first hollow tubular segment to the downstream end (32) of the first hollow tubular segment (20). The first hollow tubular segment (26) has a length of about 8 mm, an outer diameter of about 7.25 mm, and an inner diameter of about 1.9 mm. Thus, the thickness of the periphery wall of the first hollow tubular segment (26) is about 2.67 mm.

[0229] The aerosol cooling element (24) includes a second hollow tubular segment (34). The second hollow tubular segment (34) is provided in the form of a hollow cylindrical tube made of cellulose acetate. The second hollow tubular segment (34) defines an internal cavity (36) that extends completely from the upstream end (38) of the hollow tubular segment to the downstream end (40) of the second hollow tubular segment (34). The second hollow tubular segment (34) has a length of about 8 mm, an outer diameter of about 7.25 mm, and an inner diameter of about 3.25 mm. Thus, the thickness of the periphery wall of the second hollow tubular segment (34) is about 2 mm.

[0230] The aerosol generating article (10) includes an air vent (60) provided at a position approximately 2 mm from the upstream end of the second hollow tubular segment (34). The air vent (60) includes a circumferential perforation row penetrating the paper wrapper (70).

[0231] The downstream section (14) further includes a mouthpiece element (42) located immediately downstream of the aerosol cooling element (24). The upstream end of the mouthpiece element (42) is in contact with the downstream end (40) of the aerosol cooling element (24).

[0232] The mouthpiece element (42) is provided in the form of a cylindrical plug of low-density cellulose acetate. The mouthpiece element (42) has a length of about 12 mm and an outer diameter of about 7.25 mm.

[0233] The upstream section (16) includes an upstream element (46) located immediately upstream of the rod (12) of the aerosol-forming substrate, and the upstream element (46) is aligned longitudinally with the rod (12). The downstream end of the upstream element (46) borders the upstream end of the rod (12). The upstream element (46) is provided in the form of a cylindrical plug of cellulose acetate. The upstream element (46) has a length of about 5 mm.

[0234] The rod (12) of the aerosol-forming material has an outer diameter of about 7.25 mm and a length of about 12 mm.

[0235] The upstream element (46), the aerosol forming material rod (12), the support element (22), the aerosol cooling element (24), and the mouthpiece element (42) are surrounded by a paper wrapper (70).

[0236] The aerosol-forming material rod (12) comprises an aerosol-forming material, non-expanded graphite particles (44), and expanded graphite particles (45). The aerosol-forming material comprises a reconstituted and corrugated sheet comprising tobacco material, glycerin, cellulose fibers, and guar gum.

[0237] Non-expanding graphite particles (44) are Graphit Kropfm These are FP 99.5 L (>99.5% purity) natural graphite particles from hl GmbH, AMG Graphite GK, but any suitable non-expanded graphite may be used. These non-expanded graphite particles are natural graphite particles with a carbon content of 99.7% and an ash content of 0.3%, and when measured using laser diffraction with a Sympatec HELOS laser diffraction sensor, the particle size of volume D10 is 7 μm, the particle size of volume D50 is 21 μm, and the particle size of volume D90 is 55 μm.

[0238] Expanded graphite particles (45) are Graphit Kropfm SC 20 OS (>99% purity) expanded graphite particles from hl GmbH, AMG Graphite GK, but any suitable expanded graphite may be used. These expanded graphite particles have a carbon content of 99.1% and an ash content of 0.9%, and when measured using laser diffraction with a Sympatec HELOS laser diffraction sensor, the particle size of volume D10 is 6.5 μm, the particle size of volume D50 is 20 μm, and the particle size of volume D90 is 56 μm.

[0239] Each particle (44, 45) is substantially spherical in shape.

[0240] The aerosol-forming substrate has the following composition on a dry weight basis:

[0241] · 64% by weight tobacco;

[0242] · 18 wt% glycerin;

[0243] · 7.4 wt% non-expanding graphite;

[0244] · 4.6 wt% expanded graphite;

[0245] · 4 wt% fibers, particularly cellulose fibers; and

[0246] · 2 wt% binder, especially guar gum.

[0247] However, as will be understood by those skilled in the art after reading the present disclosure, other compositions comprising compositions having much higher levels of non-expanding graphite and expanded graphite are also possible.

[0248] The aerosol-forming material rod (12) is formed by a process comprising the following steps:

[0249] · A step of forming a first premix by premixing a binder and guar gum with an aerosol-forming agent and glycerin;

[0250] · A step of forming a second premix by premixing a powder composed of cellulose fibers, finely crushed tobacco material, and particles (44, 45);

[0251] · A step of mixing the above first and second premixes with water to form a slurry;

[0252] · A step of homogenizing the slurry using a high-shear mixer;

[0253] · A step of casting the above slurry onto a conveyor belt;

[0254] · A step of controlling the thickness of the slurry and drying the slurry to form a large sheet of an aerosol-forming substrate; and

[0255] · A step of forming a large crimped sheet by crimping a large sheet using a crimping roller; and

[0256] · A step of crimping and cutting a large crimp sheet of the aerosol-forming substrate to form a rod (12) of the aerosol-forming substrate.

[0257] Advantageously, the presence of graphite, particularly expanded graphite, means that the resulting aerosol-forming substrate has high thermal conductivity, and the presence of non-expanded graphite allows the substrate to be easily manufactured with conventional machinery because the non-expanded graphite corresponds to the effect of expanded graphite that increases the viscosity of the slurry.

[0258] After forming a rod (12) of an aerosol-forming material, the aerosol-generating article (10) is assembled by positioning various components of the article (10) and wrapping the components with a wrapper (70).

[0259] FIG. 2 shows a schematic cross-sectional view of a first embodiment of an aerosol generating system (100). The system (100) includes an aerosol generating device (102) and an aerosol generating article (10) of FIG. 1.

[0260] The aerosol generating device (102) includes a battery (104), a controller (106), a heating blade (108) coupled to the battery, and a puff detection mechanism (not shown). The controller (106) is coupled to the battery (104), the heating blade (108), and the puff detection mechanism.

[0261] The aerosol generating device (102) further comprises a housing (110) defining a substantially cylindrical cavity for accommodating a portion of the article (10). A heating blade (108) is positioned at the center of the cavity and extends longitudinally from the base of the cavity.

[0262] In this embodiment, the heating blade (108) includes a substrate and an electric resistance track located on the substrate. A battery (104) is coupled to the heating blade (108) so as to pass current through the electric resistance track and heat the electric resistance track and the heating blade (108) to an operating temperature of about 400°C.

[0263] When in use, the user inserts the article (10) into the cavity so that the heating blade (108) penetrates the upstream element (46) and the rod (12) of the aerosol-forming substrate of the article (10). FIG. 2 shows the article (10) inserted into the cavity of the device (102).

[0264] Then, the user puffs at the downstream end of the item (10). This causes air to flow into the user's mouth through the air inlet (not shown) of the device (102), then through the item (10), from the upstream end (18) to the downstream end (20).

[0265] The user puffing the item (10) causes air to flow through the air inlet of the device. The puff detection mechanism detects that the airflow velocity through the air inlet has increased significantly above a critical flow rate that is not zero. Accordingly, the puff detection mechanism transmits a signal to the controller (106). Then, the controller (106) controls the battery (104) to pass current through the electric resistance track and heat the heating blade (108). This heats the rod (12) of the aerosol-forming material that is in contact with the heating blade (108).

[0266] The particles (44, 45) have significantly higher thermal conductivity than the surrounding aerosol-forming material. As such, these particles (44, 45) can act as localized hot spots and provide a more uniform temperature radially from the heating blade (108) across the entire aerosol-forming substrate, particularly in the prior art substrate, where there may be a significant temperature gradient. This allows a greater proportion of the aerosol-forming substrate to reach a temperature high enough to release volatile compounds, and thus can result in higher utilization efficiency of the aerosol-forming substrate.

[0267] Heating the aerosol-forming substrate causes the aerosol-forming substrate to release volatile compounds. These compounds are entrained by air flowing from the upstream end (18) of the article (10) toward the downstream end (20) of the article (10). The compounds are cooled and condensed to form an aerosol as they pass through the internal cavities (28, 36) of the support element and the aerosol cooling element. Then, the aerosol passes into the user's mouth through a mouthpiece element (42) capable of filtering unwanted particles entrained in the airflow.

[0268] When the user stops inhaling the item (10), the airflow velocity through the air inlet of the device decreases to a non-zero critical flow rate. This is detected by a puff detection mechanism. The puff detection mechanism transmits a signal to the controller (106) accordingly. Then, the controller (106) controls the battery (104) to reduce the current passing through the electric resistance track to zero.

[0269] After puffing the item (10) several times, the user may choose to replace the item (10) with a new item.

[0270] FIG. 3 shows a schematic cross-sectional view of a second embodiment of an aerosol generating system (200). The system (200) includes an aerosol generating device (202) and an aerosol generating article (10) of FIG. 1.

[0271] The aerosol generating device (202) includes a battery (204), a controller (206), an inductor coil (208), and a puff detection mechanism (not shown). The controller (206) is coupled to the battery (204), the inductor coil (208), and the puff detection mechanism.

[0272] The aerosol generating device (202) further includes a housing (210) that defines a substantially cylindrical cavity for accommodating a portion of the article (10). An inductor coil (208) spirals around the cavity.

[0273] The battery (204) is coupled to the inductor coil (208) so that alternating current can pass through the inductor coil (208).

[0274] When in use, the user inserts the item (11) into the cavity. FIG. 3 shows the item (10) inserted into the cavity of the device (202).

[0275] Then, the user puffs at the downstream end of the item (10). As a result, air flows through the air inlet (not shown) of the device (202), then passes through the item (10), from the upstream end (18) to the downstream end (20), and into the user's mouth.

[0276] A user puffing the item (10) causes air to flow through the air inlet of the device. A puff detection mechanism detects that the airflow velocity through the air inlet has increased significantly above a critical flow rate that is not zero. Accordingly, the puff detection mechanism transmits a signal to the controller (206). Then, the controller (206) controls the battery (204) to pass alternating current through the inductor coil (208). This causes the inductor coil (208) to generate a fluctuating electromagnetic field. The rod (13) of the aerosol-forming material is positioned within this fluctuating electromagnetic field, and the non-expanded graphite and expanded graphite, which are the materials of the particles (44, 45), are susceptor materials. Thus, the fluctuating electromagnetic field causes eddy currents in the particles (44, 45). This causes the particles (44, 45) to heat up, thereby also heating the adjacent aerosol-forming material.

[0277] Heating of the aerosol-forming material causes the aerosol-forming material to release volatile compounds. These compounds are entrained by air flowing from the upstream end (18) of the article (10) toward the downstream end (20) of the article (10). The compounds are cooled and condensed to form an aerosol as they pass through the internal cavities (28, 36) of the support element and the aerosol cooling element. Then, the aerosol passes into the user's mouth through a mouthpiece element (42) capable of filtering unwanted particles entrained in the airflow.

[0278] When the user stops inhaling the item (10), the airflow velocity through the air inlet of the device decreases to a non-zero critical flow rate. This is detected by a puff detection mechanism. The puff detection mechanism transmits a signal to the controller (206) accordingly. Then, the controller (206) controls the battery (204) to reduce the current passing through the electric resistance track to zero.

[0279] After puffing the item (10) several times, the user may choose to replace the item (10) with a new item.

[0280] The aerosol-forming substrate of the article (10) illustrated in FIGS. 1, 2 and 3 was found by the inventors to have improved performance compared to alternative substrates during experiments. In this context, performance refers to the nicotine and glycerin yields from an aerosol-generating article containing the aerosol-forming substrate. This improvement is illustrated by the data in Table 2 below. To collect the data in Table 2, three different plugs of the aerosol-forming substrate were manufactured using a standard conventional machine including, in this case, a developed winder, and then tested under Health Canada Intense (HCI) smoking conditions for 12 puffs using FTIR spectroscopy. However, as will be understood by those skilled in the art, plugs of the aerosol-forming substrate may be manufactured using other techniques, e.g., by hand, and data may be collected using other tests.

[0281] Table 2:

[0282]

[0283] FIG. 4 shows a schematic cross-sectional view of a second embodiment of an aerosol generating article (510). This second embodiment is identical to the first embodiment of FIG. 1 except that the rod (12) of the aerosol forming material is replaced with an alternative rod (512) of the aerosol forming material. The same reference numerals were used for the same components in the embodiments of FIG. 1 and FIG. 3.

[0284] The rod (512) of the aerosol-forming substrate of the second embodiment of FIG. 4 is identical to the rod (12) of the aerosol-forming substrate of the first embodiment of FIG. 1, except that the rod (512) of the aerosol-forming substrate of the third embodiment of FIG. 4 additionally includes an elongated susceptor element (580).

[0285] The susceptor element (580) is arranged substantially longitudinally within the rod (512) of the aerosol-forming material so as to be approximately parallel to the longitudinal axis of the rod (512) of the aerosol-forming material. As illustrated in the drawing of FIG. 4, the susceptor element (580) is located at the radial center within the rod and extends along the longitudinal axis of the rod (12).

[0286] The susceptor element (580) extends completely from the upstream end to the downstream end of the rod (512) of the aerosol-forming material. In this way, the susceptor element (580) has substantially the same length as the rod (512) of the aerosol-forming material.

[0287] In the embodiment of FIG. 4, the susceptor element (580) is provided in the form of a strip of ferromagnetic steel and has a length of about 12 mm, a thickness of about 60 μm, and a width of about 4 mm.

[0288] The aerosol generating article (510) of FIG. 4 can be used with the aerosol generating device (202) of FIG. 3 in the same way as the aerosol generating article (10) of FIG. 1. In particular, including a susceptor element (580) means that the article (510) can be inductively heated. In the example illustrated in FIG. 4, both the particles (44, 45) and the susceptor element (580) are inductively heated. Thus, both the susceptor element (580) and the particles (44, 45) contribute to heating during use.

[0289] FIG. 5 illustrates an example of an aerosol generating article (1000) comprising a tobacco-free aerosol forming substrate.

[0290] The aerosol generating article (1000) comprises four elements: an aerosol forming substrate (1020), a hollow cellulose acetate tube (1030), a spacer element (1040), and a mouthpiece filter (1050). The four elements (1020, 1030, 1040, 1050) are arranged sequentially and concentrically. The four elements (1020, 1030, 1040, 1050) are assembled by cigarette paper (1060) to form the aerosol generating article (1000).

[0291] The aerosol generating article (1000) has a mouse end (1012) and a distal end (1013). The user may insert the mouse end (1012) into their mouth during use. The distal end (1013) is located at the opposite end of the aerosol generating article (1000) to the mouse end (1012). The example of the aerosol generating article (1000) shown in FIG. 5 is particularly suitable for use in an electric aerosol generating device including a heater for heating an aerosol generating substrate.

[0292] When assembled, the aerosol generating article (1000) has a length of about 45 millimeters, an outer diameter of about 7.2 millimeters, and an inner diameter of about 6.9 millimeters.

[0293] The aerosol-forming substrate (1020) is provided in the form of a plug manufactured by crimping a sheet of the aerosol-forming substrate. A number of example compositions of the aerosol-forming substrate (1020) are shown in the table below. A sheet is crimped and wrinkled, and wrapped in filter paper (not shown) to form a plug.

[0294] As illustrated in FIG. 5, the aerosol generating article (1000) is designed to be connected to an aerosol generating device for consumption. Such an aerosol generating device includes means for heating an aerosol forming substrate (1020) to a temperature sufficient to form an aerosol. Generally, the aerosol generating device may include a heating element surrounding the aerosol generating article (1000) adjacent to the aerosol forming substrate (1020), or a heating element inserted within the aerosol forming substrate (1020).

[0295] Once connected to the aerosol generating device, the user inhales the mouth end (1012) of the smoking item (1000), and the aerosol forming substrate (1020) is heated to a temperature of about 375°C. At this temperature, volatile compounds including nicotine and glycerin of Examples A to E described below are released from the aerosol forming substrate (1020). These compounds condense to form an aerosol. The aerosol is inhaled into the user's mouth through a filter (1050).

[0296] FIG. 6 shows a part of an electric aerosol generating system (2000). The aerosol generating system heats the aerosol generating substrate (1020) of an aerosol generating article (1000) using a heating blade (2100). In the example of FIG. 6, the heating blade (2100) is mounted within the aerosol article receiving chamber of an electric aerosol generating device (2010). The aerosol generating device (2010) defines a plurality of air holes (2050) to allow air to flow into the aerosol generating article (1000). The air flow is indicated by arrows in FIG. 6. The aerosol generating device (2010) includes a power supply and electronic devices, which are not shown in FIG. 6. The aerosol generating article (1000) of FIG. 6 is as described in relation to FIG. 5.

[0297] Exemplary compositions of the aerosol-forming substrates (Examples A, B, C, D, and E) illustrated in FIGS. 5 and 6 are shown in Table 3 below. All weight% values ​​are measured on a dry weight basis.

[0298] Table 3:

[0299]

[0300] In all of Examples A, B, C, D, and E, the substrate comprises 7.4 wt% non-expanded graphite and 4.6 wt% expanded graphite on a dry weight basis. These non-expanded graphite and expanded graphite may be present in the form of particles or in any other suitable manner with respect to the substrate illustrated and described with reference to FIGS. 1 to 4.

[0301] Advantageously, the presence of non-expanded graphite and expanded graphite, particularly expanded graphite, means that the resulting aerosol-forming substrate has high thermal conductivity. Also, the presence of non-expanded graphite allows the substrate to be easily manufactured using conventional machinery because the non-expanded graphite corresponds to the effect of expanded graphite in increasing the viscosity of the slurry.

[0302] The aerosol-forming substrates of Examples A, B, C, D, and E are prepared by the following:

[0303] (1) A step of forming a slurry by mixing ingredients with water using heat and stirring;

[0304] (2) A step of casting the layer of the slurry onto a plane to form a film having a thickness of about 210 μm;

[0305] (3) A step of leaving the above film on the plane to solidify it; and

[0306] (3) The above film is heated to about 140°C for about 8 minutes to dry the film and form a solid aerosol-forming substrate.

[0307] For the purposes of this description and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, etc., shall be understood in all cases as being modified by the term “about.” Additionally, all ranges include the disclosed maximum and minimum points and contain any intermediate ranges that may or may not be specifically enumerated herein. Accordingly, in this context, the number A is understood as 10% of A ± A. In this context, the number A may be considered to include numerical values ​​within the general standard error for measuring the characteristic that the number A modifies. In some examples used in the appended claims, the number A may deviate by the percentages listed above, provided that the amount of deviation does not substantially affect the basic and novel feature(s) of the claimed invention. Additionally, all ranges include the disclosed maximum and minimum points and contain any intermediate ranges that may or may not be specifically enumerated herein.

Claims

Claim 1 An aerosol-forming substrate comprising, based on dry weight, X weight% non-expanded graphite; and Y weight% expanded graphite, wherein the value obtained by dividing X by Y is at least 0.

5. Claim 2 An aerosol-forming substrate according to claim 1, wherein the value of X divided by Y is 0.65 to 8. Claim 3 An aerosol-forming substrate according to claim 1 or 2, wherein the value of X divided by Y is 0.8 to 4. Claim 4 An aerosol-forming substrate according to any one of claims 1 to 3, wherein the value obtained by dividing X by Y is 1.0 to 2. Claim 5 An aerosol-forming substrate according to any one of paragraphs 1 to 4, wherein X is at least 4. Claim 6 In paragraph 5, X is 4 to 12, an aerosol-forming substrate. Claim 7 An aerosol-forming substrate according to any one of claims 1 to 6, wherein Y is at least 3. Claim 8 In claim 7, the aerosol-forming substrate, where Y is 3 to 10. Claim 9 An aerosol-forming substrate according to any one of claims 1 to 8, wherein the X weight% non-expanding graphite comprises or is composed of a plurality of non-expanding graphite particles; and the Y weight% expanded graphite comprises or is composed of a plurality of expanded graphite particles. Claim 10 In claim 9, the plurality of non-expanding graphite particles have a particle size distribution having a volume D90 diameter of 75 μm or less, an aerosol-forming substrate. Claim 11 An aerosol-forming substrate according to claim 9 or 10, wherein the plurality of expanded graphite particles have a particle size distribution having a volume D90 diameter of 75 μm or less. Claim 12 An aerosol generating article comprising an aerosol-forming material according to any one of claims 1 to 11. Claim 13 In paragraph 12, the aerosol-forming substrate is an aerosol-generating article in the form of a crimped and corrugated sheet. Claim 14 An aerosol generating system comprising an aerosol generating article and an aerosol generating device according to paragraph 12 or 13. Claim 15 A method for forming an aerosol-forming substrate according to any one of claims 1 to 11, wherein the method comprises: a step of forming a slurry comprising non-expanded graphite and expanded graphite; and a step of casting and drying the slurry to form the aerosol-forming substrate or a precursor for forming the aerosol-forming substrate.

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