Aerosol-forming substrate having expanded graphite

Abstract

An aerosol-forming substrate for use in a heated aerosol-generating article includes expanded graphite particles, which have high thermal conductivity and low density and can improve the efficiency of aerosol delivery from the substrate.

Description

[Technical Field]

[0001] This disclosure relates to aerosol-forming substrates. This disclosure also relates to methods for producing aerosol-forming substrates, aerosol-generating articles, and aerosol-generating systems. [Background technology]

[0002] A typical aerosol generation system comprises an aerosol generator and an aerosol-generating article containing an aerosol-forming substrate. During use, the aerosol generator interacts with the aerosol-generating article to heat the aerosol-forming substrate, causing it to release volatile compounds. These compounds then cool to form an aerosol, which is inhaled by the user.

[0003] Known aerosol-forming substrates typically have relatively low thermal conductivity. This can be particularly undesirable in aerosol generation systems where a blade is inserted into the aerosol-forming substrate for heating. This is because the low thermal conductivity of the aerosol-forming substrate can result in a relatively large temperature gradient during use. This means that the portion of the aerosol-forming substrate furthest from the blade will not reach high temperatures and therefore will not release as many volatile compounds as a substrate with higher thermal conductivity. In other words, the undesirability of aerosol-forming substrates can lead to low utilization efficiency.

[0004] Furthermore, known aerosol-forming substrates are typically not heatable to operating temperature by induction. This means that a separate susceptor element is typically required for induction heating, which can increase costs. Moreover, this can lead to the same problems mentioned above. For example, if the induction heating susceptor element is located in the center of the substrate, the portion of the aerosol-forming substrate furthest from the susceptor element may not reach high temperatures and therefore may not release many volatile compounds.

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

[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. [Overview of the project]

[0007] This disclosure provides an aerosol-forming substrate containing expanded graphite particles. The aerosol-forming substrate may include an aerosol-forming material such as expanded graphite particles and an aerosol-forming body. The aerosol-forming substrate may contain more than 0.1% by weight (wt.%) of expanded graphite particles. The volume-average particle size of the expanded graphite particles may be greater than 5 microns, for example, greater than 10 microns. The aerosol-forming substrate may have a thermal conductivity greater than that of a homogenized tobacco substrate. The aerosol-forming substrate may have a thermal conductivity greater than 0.12 W / mk in at least one direction when measured at a temperature of, for example, 25 degrees Celsius. In some specific embodiments, the aerosol-forming substrate may have a thermal conductivity greater than 0.22 W / mk in at least one direction when measured at a temperature of, for example, 25 degrees Celsius.

[0008] An exemplary aerosol-forming substrate may comprise, on a dry weight basis, 1 to 90% by weight of expanded graphite particles, each of which has a thermal conductivity of at least 1 W / (mK) in at least one direction at 25 degrees Celsius; 7 to 60% by weight of an aerosol-forming body; 2 to 20% by weight of fibers; and 2 to 10% by weight of a binder, wherein the aerosol-forming substrate has a thermal conductivity of at least 0.12 W / (mK) in at least one direction at 25 degrees Celsius. For example, an exemplary aerosol-forming substrate may comprise 1 to 10% by weight of expanded graphite particles, on a dry weight basis, where each expanded graphite particle has a thermal conductivity of at least 1 W / (mK) in at least one direction at 25 degrees Celsius; 7 to 20% by weight of an aerosol-forming material; 2 to 20% by weight of fibers; and 2 to 10% by weight of a binder, wherein the aerosol-forming substrate has a thermal conductivity of at least 0.12 W / (mK) in at least one direction at 25 degrees Celsius. The aerosol-forming substrate may contain nicotine. The aerosol-forming substrate may contain tobacco.

[0009] Advantageously, the expanded graphite particles can increase the thermal conductivity of the aerosol-forming substrate. The increased thermal conductivity of the substrate can provide a more uniform temperature distribution throughout the substrate during use. This allows a larger proportion of the aerosol-forming substrate to reach a temperature high enough to release volatile compounds, thus potentially increasing the efficiency of use of the aerosol-forming substrate. Furthermore, the increased thermal conductivity of the substrate allows heaters, such as heating blades configured to heat the substrate, to operate at lower temperatures, thus requiring less power. In addition, the increased thermal conductivity of the substrate may allow heaters to heat the substrate to a temperature at which volatile compounds are released in a shorter time. Therefore, the increased thermal conductivity can reduce the time required to form an aerosol that can be inhaled by the user.

[0010] Expanded graphite is a modified graphite material. Expanded graphite has a layered structure similar to graphite, but with increased or expanded interlayer spacing. Particularly advantageous is that expanded graphite has a lower density than graphite. Therefore, aerosol-forming substrates consisting of expanded graphite particles can be formed at a lower density compared to similar substrates manufactured using ordinary, non-expanded graphite or other conductive particles of equivalent particle size. A lower-density substrate may allow for the manufacture of aerosol-generating articles with a lower total weight while providing equivalent aerosol delivery. This can advantageously reduce transport costs. Even a lower-density aerosol-forming substrate can have lower thermal inertia if it has equivalent or greater thermal conductivity, thereby reducing preheating time and shortening the time to initial fuming.

[0011] Advantageously, one or both of the fibers and / or the binder can increase the tensile strength of the aerosol-forming substrate. Increased tensile strength can enable the production of aerosol-forming substrate sheets that are not easily torn. Increased tensile strength may also enable the production of aerosol-forming substrate sheets using existing manufacturing machinery.

[0012] As described above, the aerosol-forming substrate may have a thermal conductivity of at least 0.12 W / (mK), for example, at least 0.22 W / mK, in at least one direction at 25 degrees Celsius. This thermal conductivity can be measured when the water content of the substrate is 0-20%, or 5-15%, for example, about 10%. This thermal conductivity may also be measured when the substrate contains 0-20% by weight, or 5-15% by weight, for example, about 10% by weight of water. The water content of the substrate may be measured using titration. The water content of the substrate may also be measured using the Karl Fisher method.

[0013] Expanded graphite particles may have anisotropic thermal conductivity values. Some or each of the expanded graphite particles may have thermal conductivity values ​​of 2, 5, 10, 20, 50, 100, 200, 500, or greater than 1000 W / mK in at least one direction, for example, when measured at 25 degrees Celsius.

[0014] Expanded graphite can be expanded up to 100 to 300 times compared to non-expanded graphite. Expanded graphite can have a density of less than 2, 1.8, 1.5, 1.2, 1, 0.8, or 0.5, 0.2, 0.1, 0.05, 0.02 grams per cubic centimeter (g / cm 3 ). Expanded graphite can have a density greater than 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 0.8, 1, 1.2, 1.5, or 1.8 grams per cubic centimeter (g / cm 3 ). Expanded graphite can have a density of 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 0.5 g / 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 grams per cubic centimeter (g / cm 3 ).

[0015] Expanded graphite particles can each have a certain "particle size". The meaning of the term "particle size" and the method for measuring the particle size will be described later.

[0016] The expanded graphite particles can be characterized by a particle size distribution. The particle size distribution can have number D10, D50, and D90 particle sizes. The number D10 particle size is defined such that 10% of the particles have a particle size that is less than or equal to the number D10 particle size. Similarly, the number D50 particle size is defined such that 50% of the particles have a particle size that is less than or equal to the number D50 particle size. Thus, the number D50 particle size can also be referred to as the median particle size. The number D90 particle size is defined such that 90% of the particles have a particle size that is less than or equal to the number D90 particle size. Thus, if there are 1,000 particles in the distribution and the particles are arranged in ascending order by particle size, the number D10 particle size is expected to be approximately equal to the 100th particle size, the number D50 particle size is expected to be approximately equal to the 500th particle size, and the number D90 particle size is expected to be approximately equal to the 900th particle size.

[0017] The particle size distribution can have volume D10, D50, and D90 particle sizes. The volume D10 particle size is defined such that 10% of the total volume of all the particles is occupied by the total volume of the particles having a particle size that is less than or equal to the volume D10 particle size. Similarly, the volume D50 particle size is defined such that 50% of the total volume of all the particles is occupied by the total volume of the particles having a particle size that is less than or equal to the volume D50 particle size. Also, the volume D90 particle size is defined such that 90% of the total volume of all the particles is occupied by the total volume of the particles having a particle size that is less than or equal to the volume D90 particle size.

[0018] Optionally, the expanded graphite particles have a particle size distribution having a number D10 particle size, and the number D10 particle size is at least 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 microns.

[0019] Optionally, the thermally conductive particles have a particle size distribution having a number D10 particle size, and the number D10 particle size is 1,000, 500, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, or 0.2 microns or less.

[0020] A compromise must be made when determining the particle size. Larger expanded graphite particles can favorably increase the thermal conductivity of the aerosol-forming substrate compared to smaller expanded graphite particles. However, larger expanded graphite particles may reduce the available space within the substrate for the aerosol-forming material.

[0021] Selectively, the expanded graphite particles have a particle size distribution with several D50 particle sizes, where several D50 particle sizes are at least 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 microns.

[0022] Selectively, the thermally conductive particles have a particle size distribution with particle sizes of several D50, where the particle sizes of several D50 are 1,000, 500, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, or 0.2 microns or less.

[0023] Selectively, the expanded graphite particles have a particle size distribution with several D90 particle sizes, where several D90 particle sizes are at least 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 microns.

[0024] Selectively, the thermally conductive particles have a particle size distribution with a number D90 particle size, where the number D90 particle size is 1,000, 500, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, or 0.2 microns or less.

[0025] Selectively, the expanded graphite particles have a particle size distribution with particle sizes of several D10 and several D90, where the particle size of several D90 is 50, 40, 30, 20, 10, or 5 times or less the particle size of several D10.

[0026] Selectively, the expanded graphite particles have a particle size distribution with several D10 particle sizes and several D90 particle sizes, where the several D90 particle size is at least 1.5, 2, 3, 5, 10, or 20 times the several D10 particle size.

[0027] A compromise is necessary regarding the particle size distribution. For example, a tighter particle size distribution, characterized by a small ratio between D90 and D10 particle sizes, can advantageously provide a more uniform thermal conductivity throughout the aerosol-forming substrate. This is because there is less variation in particle size at different locations within the substrate. This can advantageously enable more efficient use of the aerosol-forming material throughout the aerosol-forming substrate. However, a tight particle size distribution can be inconveniently more difficult and expensive to achieve. The inventors have found that the particle size distribution described above can offer an optimal compromise between these two factors.

[0028] Selectively, the expanded graphite particles have a particle size distribution having a volume D10 particle size, where the volume D10 particle size is at least 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 microns.

[0029] Selectively, the expanded graphite particles have a particle size distribution with a volume D10 particle size, where the volume D10 particle size is 1,000, 500, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, or 0.2 microns or less.

[0030] Optionally, the expanded graphite particles have a particle size distribution having a volume D50 particle size, where the volume D50 particle size is at least 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 microns.

[0031] Selectively, the expanded graphite particles have a particle size distribution with a volume D50 particle size, where the volume D50 particle size is 1,000, 500, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, or 0.2 microns or less.

[0032] Selectively, the expanded graphite particles have a particle size distribution having a volume D90 particle size, where the volume D90 particle size is at least 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 microns.

[0033] Selectively, the expanded graphite particles have a particle size distribution with a volume D90 particle size of 1,000, 500, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, or 0.2 microns or less.

[0034] It is particularly preferable that the expanded graphite particles have a particle size distribution with a volume D10 particle size of 1 to 20 microns. Alternatively or additionally, it is particularly preferable that the expanded graphite particles have a particle size distribution with a volume D90 particle size of 50 to 300 microns, or 50 to 200 microns.

[0035] Selectively, the expanded graphite particles have a particle size distribution with volume D10 particle size and volume D90 particle size, where the volume D90 particle size is 50, 40, 30, 20, 10, or 5 times or less the volume D10 particle size.

[0036] Selectively, the expanded graphite particles have a particle size distribution with volume D10 particle size and volume D90 particle size, where the volume D90 particle size is at least 1.5, 2, 3, 5, 10, or 20 times the volume D10 particle size.

[0037] Expanded graphite may have a volume-average particle size of 1, 2, 3, 5, 10, 20, 30, 35, 50, 75, 100, 150, 200, 250, 500, or 900 micrometers or larger.

[0038] It is particularly preferable that the volume-average particle size of the expanded graphite particles is greater than 10 micrometers.

[0039] Expanded graphite particles may have a volume-average particle size of 1000, 900, 500, 200, 100, 150, 100, 75, 50, 35, 30, 20, 10, 5, 3, or 2 micrometers or less. Expanded graphite particles may have a volume-average particle size of 1 to 1000, 35 to 1000, or 100 to 900 micrometers. These particle size ranges may be particularly preferred when the aerosol-forming material contains or is in the form of one or more of the following: cut fillers, powder particles, granules, pellets, fragments, spaghetti, slivers, or sheets.

[0040] Expanded graphite particles may have volume-average particle sizes of 1-1000, 10-200, 30-150, or 50-75 micrometers. These volume-average particle size ranges may be particularly preferred when the aerosol-forming material contains sheets, such as an aggregate of sheets, or is in the form of sheets.

[0041] Expanded graphite particles may have a volume-average particle size at least 2, 3, 5, 8, 10, 15, or 20 times their number-average particle size.

[0042] As explained above, a compromise was necessary regarding the particle size distribution, and the inventors found that the above particle size distribution could provide an optimal compromise.

[0043] Optionally, each expanded graphite particle may have a particle size of at least 0.01, 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 microns. Optionally, each expanded graphite particle may have a particle size of 1,000, 500, 300, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, or 0.2 microns or less. It may be particularly preferable that each expanded graphite particle has a particle size of at least 1 micron. Alternatively or additionally, it may be particularly preferable that each expanded graphite particle has a particle size of 300 microns or less. Particles smaller than 1 micron may be difficult to handle during manufacturing. Particles larger than 300 microns may occupy a considerably large space in the substrate that can be used in aerosol-forming materials. Therefore, it may be particularly advantageous for each of the expanded graphite particles to have a particle size of at least 1 micron, or a particle size of 300 microns or less, or both.

[0044] Optionally, each expanded graphite particle has three mutually orthogonal dimensions, and the largest of the three dimensions is no more than 10, 8, 5, 3, or 2 times the smallest of the three dimensions. Optionally, each expanded graphite particle has three mutually orthogonal dimensions, and the largest of the three dimensions is no more than 10, 8, 5, 3, or 2 times the second largest of the three dimensions. Optionally, each expanded graphite particle is substantially spherical.

[0045] Optionally, the aerosol-forming substrate contains at least 10, 20, 50, 100, 200, 500, or 1000 expanded graphite particles. Advantageously, a larger number of expanded graphite particles in the aerosol-forming substrate may allow for more uniform thermal conductivity of the substrate.

[0046] In some embodiments, the aerosol-forming substrate may have a relatively low proportion of expanded graphite particles. For example, the substrate may contain an aerosol-forming material such as homogenized tobacco containing 0.1 to 25% by weight of expanded graphite particles. The expanded graphite particles may account for 80, 50, 20, 10, or 5% by weight or less of the aerosol-forming substrate. The expanded graphite particles may account for 0.1, 0.2, 0.5, 1, 2, 3, 5, 10, 20, or 50% by weight or more of the aerosol-forming substrate. Expanded graphite particles may constitute 0.1-20, 0.2-20, 0.5-20, 1-20, 2-20, 3-20, 5-20, 0.1-15, 0.2-15, 0.5-15, 1-15, 2-15, 3-15, 5-15, 0.1-10, 0.2-10, 0.5-10, 1-10, 2-10, 3-10, or 5-10% by weight of the aerosol-forming substrate. Expanded graphite particles may constitute 0.1-20, 0.2-20, 0.5-20, 1-20, 2-20, 3-20, 5-20, 0.1-15, 0.2-15, 0.5-15, 1-15, 2-15, 3-15, 5-15, 0.1-10, 0.2-10, 0.5-10, 1-10, 2-10, 3-10, or 5-10% by weight of the aerosol-forming substrate.

[0047] It may be particularly preferable that the expanded graphite particles constitute more than 1% by weight of the aerosol-forming substrate. It may also be preferable that the expanded graphite particles constitute less than 20% by weight of the aerosol-forming substrate. Advantageously, the inventors have found that these weight percentages offer an optimal compromise between increasing the thermal conductivity of the aerosol-forming substrate and maintaining sufficient aerosol-forming material, such as homogenized tobacco, to form an appropriate amount of aerosol. It may be particularly preferable that the expanded graphite particles constitute 1–20, 2–15, or 3–10% by weight of the aerosol-forming substrate. This is because the inventors have found that for certain aerosol-forming substrates, these weight percentage ranges may provide more consistent glycerol and nicotine delivery over approximately 12 puffs. While we do not wish to be bound by theory, it is believed that having less than 1, 2, or 3 wt% of expanded graphite particles does not have a sufficiently large effect on the thermal conductivity of the substrate, while more than 10, 15, or 20 wt% of expanded graphite particles raise the local substrate temperature excessively high and excessively quickly, resulting in relatively high glycerol and nicotine delivery in the initial inhalation, but relatively low glycerol and nicotine delivery in subsequent inhalations. In addition, we have surprisingly found that for certain aerosol-forming substrates, the total yield of glycerol and nicotine over approximately 12 inhalations appears to be maximized for substrates having 1–20, 2–15, or 3–10 wt% of expanded graphite particles. This may be advantageous because less substrate may be required to deliver the same amount of glycerol and nicotine to the user.

[0048] In some embodiments, the aerosol-forming substrate may include a relatively high proportion of expanded graphite particles, e.g., expanded graphite particles, a binder, a fibrous component, and an aerosol-forming body. Optionally, the substrate may contain at least 20, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or 85% by weight of expanded graphite particles, based on dry weight. Optionally, the substrate may contain 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, or 15% by weight of expanded graphite particles, based on dry weight. Optionally, the substrate contains expanded graphite particles in the following quantities by dry weight: 10-90, 20-90, 30-90, 40-90, 50-90, 60-90, 70-90, 80-90, 10-80, 20-80, 30-80, 40-80, 50-80, 60-80, 70-80, 10-70, 20-70, 30-70, 40-70, 50-70, 60-70, 10-60, 20-60, 30-60, 40-60, 50-60, 10-50, 20-50, 30-50, 40-50, 10-40, 20-40, 30-40, 10-30, 20-30, or 10-20% by weight. The substrate may particularly preferably contain 50 to 90, more preferably 60 to 90, or even more preferably 65 to 85% by weight of expanded graphite particles on a dry weight basis.

[0049] A compromise may be necessary regarding the weight percentage of expanded graphite particles within the substrate. Increasing the weight percentage of particles in the aerosol-forming substrate can, advantageously, increase the thermal conductivity of the substrate. However, increasing the weight percentage of particles in the aerosol-forming substrate may also reduce the available space for one or more of the aerosol-forming material, binder, and fibers, potentially resulting in a substrate that forms fewer aerosols or has lower tensile strength.

[0050] Optionally, the substrate contains at least 10, 15, 20, 25, 30, 35, 40, 45, 50, or 55% by weight of aerosol-forming material on a dry weight basis. Optionally, the substrate contains 55, 50, 45, 40, 35, 30, 25, 20, or 15% by weight or less of aerosol-forming material on a dry weight basis. Optionally, the substrate contains 7-60, 10-60, 20-60, 30-60, 40-60, 50-60, 7-50, 10-50, 20-50, 30-50, 40-50, 7-40, 10-40, 20-40, 30-40, 7-30, 10-30, 20-30, 7-20, 10-20, or 7-10% by weight of aerosol-forming material on a dry weight basis. The substrate may particularly preferably contain 15 to 25% by weight of aerosol-forming material on a dry weight basis.

[0051] Optionally, the aerosol-forming body contains or consists of one or more of the following: 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 tri-acetates, and aliphatic esters or mono, di-, or polycarboxylic acids (such as dimethyldodecanediol and dimethyl tetradecanediol). Optionally, the aerosol-forming substrate contains either or both of glycerin and glycerol.

[0052] Optionally, the substrate contains at least 2, 4, 6, 8, 10, 12, 14, 16, or 18% by weight of fibers, based on dry weight. Optionally, the substrate contains 20, 18, 16, 14, 12, 10, 8, 6, or 4% or less by weight of fibers, based on dry weight. Optionally, the substrate contains 4-20, 6-20, 8-20, 10-20, 12-20, 14-20, 16-20, 18-20, 2-18, 4-18, 6-18, 8-18, 10-18, 12-18, 14-18, 16-18, 2-16, 4-16, 6-16, 8-16, 10 The material contains fibers in the following proportions: ~16, 12~16, 14~16, 2~14, 4~14, 6~14, 8~14, 10~14, 12~14, 2~12, 4~12, 6~12, 8~12, 10~12, 2~10, 4~10, 6~10, 8~10, 2~8, 4~8, 6~8, 2~6, 4~6, or 2~4% by weight. The substrate may be particularly preferably to contain 2.1~9.8% by weight of fibers on a dry weight basis.

[0053] Optionally, the fiber is a cellulose fiber. Advantageously, cellulose fibers are not excessively expensive and can increase the tensile strength of the substrate.

[0054] Optionally, each fiber has three mutually orthogonal dimensions, and the largest of the three dimensions is at least 1.5, 2, 3, 5, 10, or 20 times larger than the smallest of the three dimensions. Optionally, each fiber has three mutually orthogonal dimensions, and the largest of the three dimensions is at least 1.5, 2, 3, 5, 10, or 20 times larger than the second largest of the three dimensions.

[0055] Optionally, the substrate contains at least 4, 6, or 8% by weight of the binder, based on dry weight. Optionally, the substrate contains 8, 6, or 4% or less of the binder, based on dry weight. Optionally, the substrate contains 4-10, 6-10, 8-10, 2-8, 4-8, 6-8, 2-6, 4-6, or 2-4% by weight of the binder, based on dry weight. It may be particularly preferable that the substrate contains 2.1-10% by weight of the binder, based on dry weight.

[0056] Preferred binders are well known in the art and include, but are not limited to, natural pectin (such as fruit pectin, citrus pectin, or tobacco pectin), guar gum (such as hydroxyethyl guar and hydroxypropyl guar), locust bean gum (such as hydroxyethyl and hydroxypropyl locust bean gum), alginates, starch (such as modified starch or derivatized starch), cellulose (such as methylcellulose, ethylcellulose, ethylhydroxymethylcellulose, and carboxymethylcellulose), tamarind gum, dextran, pralon, konjac powder, xanthan gum, and similar materials. The binder may be guar or may particularly preferably contain guar. The binder may particularly preferably contain or consist of one or more of carboxymethylcellulose or hydroxypropylcellulose, or gums such as guar gum.

[0057] Optionally, expanded graphite particles are distributed substantially homogeneously throughout the aerosol-forming substrate. Optionally, aerosol-forming materials are distributed substantially homogeneously throughout the aerosol-forming substrate. Optionally, fibers are distributed substantially homogeneously throughout the aerosol-forming substrate. Optionally, binders are distributed substantially homogeneously throughout the aerosol-forming substrate. Advantageously, the homogeneous distribution of the substrate components may result in a substrate with more spatially uniform properties. For example, substantially homogeneously distributed expanded graphite particles may result in a substrate with substantially uniform thermal conductivity. In another example, substantially homogeneously distributed binders or fibers may result in a substrate with substantially uniform tensile strength.

[0058] Optionally, the substrate contains nicotine. Optionally, the substrate contains at least 0.01, 1, 2, 3, or 4% by weight of nicotine on a dry weight basis. Optionally, the substrate contains 5, 4, 3, 2, or 1% by weight or less of nicotine on a dry weight basis. Optionally, the substrate contains 0.01-5, 1-5, 2-5, 3-5, 4-5, 0.01-4, 1-4, 2-4, 3-4, 0.01-3, 1-3, 2-3, 0.01-2, 1-2, or 0.01-1% by weight of nicotine on a dry weight basis. It may be particularly preferable that the substrate contains 0.5-3% by weight of nicotine on a dry weight basis.

[0059] Selectively, nicotine is distributed substantially homogeneously throughout the aerosol-forming substrate.

[0060] Optionally, the substrate contains acid. Optionally, the substrate contains at least 0.01, 1, 2, 3, or 4% by weight of acid on a dry weight basis. Optionally, the substrate contains 5, 4, 3, 2, or 1% or less by weight of acid on a dry weight basis. Optionally, the substrate contains 0.01-5, 1-5, 2-5, 3-5, 4-5, 0.01-4, 1-4, 2-4, 3-4, 0.01-3, 1-3, 2-3, 0.01-2, 1-2, or 0.01-1% by weight of acid on a dry weight basis. It may be particularly preferable that the substrate contains 0.5-3% by weight of acid on a dry weight basis.

[0061] Optionally, the acid may contain or consist of one or more of fumaric acid, lactic acid, benzoic acid, and levulinic acid.

[0062] Selectively, the acid is distributed substantially homogeneously throughout the aerosol-forming substrate.

[0063] Optionally, the substrate contains at least one plant. Optionally, the substrate contains at least 0.01, 1, 2, 5, 10, or 15% by weight on a dry weight basis of at least one plant. Optionally, the substrate contains 20, 15, 10, 5, 2, or 1% or less by weight on a dry weight basis of at least one plant. Optionally, the substrate contains at least 0.01-20, 1-20, 2-20, 5-20, 10-20, 15-20, 0.01-15, 1-15, 2-15, 5-15, 10-15, 0.01-10, 1-10, 2-10, 5-10, 0.01-5, 1-5, 2-5, 0.01-2, 1-2, or 0.01-1% by weight on a dry weight basis of at least one plant. The substrate may be particularly preferably contain at least one plant component in an amount of 5 to 15% by weight, based on dry weight.

[0064] Optionally, at least one plant may include or consist of either clove or rosmarinus.

[0065] At least one plant is selectively distributed substantially homogeneously throughout the aerosol-forming substrate.

[0066] Optionally, the base contains at least one flavoring agent. Optionally, the base contains at least 0.1, 1, 2, or 5% by weight of at least one flavoring agent on a dry weight basis. Optionally, the base contains 10, 5, 2, or 1% or less by weight of at least one flavoring agent on a dry weight basis. Optionally, the base contains at least one flavoring agent in amounts of 0.1-10, 1-10, 2-10, 5-10, 0.1-5, 1-5, 2-5, 0.1-2, 1-2, or 0.1-1% by weight on a dry weight basis. It may be particularly preferable that the base contains at least one flavoring agent in amounts of 0.5-4.0% by weight on a dry weight basis.

[0067] Optionally, at least one flavoring agent is present as a coating, for example, a coating on one or more other components of the aerosol-forming substrate. Alternatively, or additionally, at least one flavoring agent is distributed substantially homogeneously throughout the aerosol-forming substrate.

[0068] Optionally, the aerosol-forming substrate includes at least one organic material, such as tobacco. The at least one organic material includes one or more of the following: herb leaves, tobacco leaves, tobacco stem fragments, reconstituted tobacco, homogenized tobacco, extruded tobacco, and puffed tobacco. Optionally, the at least one organic material is substantially homogeneously distributed throughout the aerosol-forming substrate.

[0069] The substrate may contain 10, 5, 3, 2, or less than 1% by weight of tobacco, on a dry weight basis. Optionally, the aerosol-forming substrate is a tobacco-free aerosol-forming substrate.

[0070] The aerosol-forming substrate may be in the form of a rod. Therefore, a rod of the aerosol-forming substrate can be provided.

[0071] The susceptor element may be located within the rod of the aerosol-forming substrate. The susceptor element may be elongated. The susceptor element may extend along its long axis within the rod of the aerosol-forming substrate. The rod may be substantially cylindrical, for example, a right cylinder. The susceptor element may be located at the radial center within the rod of the aerosol-forming substrate. The susceptor element may extend along the central long axis of the rod of the aerosol-forming substrate. The susceptor element may extend all the way to the downstream end of the rod of the aerosol-forming substrate. The susceptor element may extend all the way 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 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 millimeters, 6 to 12 millimeters, or 8 to 10 millimeters. The susceptor element may have a width of 1 to 5 millimeters. The susceptor element may have a thickness of 0.01 to 2 millimeters, 0.5 to 2 millimeters, or 0.5 to 1 millimeter.

[0072] Alternatively, the susceptor material may not be present within the aerosol-forming substrate or within the rod of the aerosol-forming substrate.

[0073] Optionally, some or each of the expanded graphite particles may be induction heated to temperatures of, for example, at least 100, 150, or 200 degrees Celsius. The expanded graphite particles may contain, or be the only, susceptor material present in the aerosol-forming substrate or rod of the aerosol-forming substrate. That is, apart from the expanded graphite particles, there may be no other susceptor elements present in the aerosol-forming substrate or rod of the aerosol-forming substrate.

[0074] Optionally, the aerosol-forming substrate has a thermal conductivity greater than 0.05, 0.1, 0.15, 0.2, 0.3, 0.4, 0.5, 0.75, 1, 1.25, 1.5, 2, 5, 10, 20, 50, 100, 200, or 500 W / (mK) at 25 degrees Celsius in at least one direction.

[0075] Optionally, the aerosol-forming substrate can be 1500, 1450, 1400, 1350, 1300, 1250, 1200, 1100, 1050, 1000, 950, 900, 850, 800, 850, 800, 750, 700, 650, or 600 kg / m 3 The following densities are observed. Optionally, the aerosol-forming substrate has a density of 600-1400 kg / m³. 3 800-1200 kg / m 3 , or 900-1100 kg / m 3 It has a density of [value missing]. Advantageously, by reducing the density of the substrate, the transportation cost of the substrate can be reduced.

[0076] Optionally, the aerosol-forming substrate has a water content of 1–20 or 3–15% by weight. This water content can be measured after 48 hours of equilibration at 50% relative humidity and 20 degrees Celsius. Optionally, the aerosol-forming substrate contains 1–20 or 3–15% by weight of water. The water content of the substrate may be measured using titration. The water content of the substrate may be measured using the Karl Fisher method.

[0077] Optionally, the aerosol-forming substrate comprises one or more of the following: cut fillers, powder particles, granules, pellets, fragments, spaghetti, strips, threads, ribbons, or sheets, or in the form thereof. Optionally, the aerosol-forming substrate comprises one or more sheets or strips, or in the form thereof.

[0078] Optionally, the aerosol-forming substrate may include or be in the form of one or more sheets, such as an assembly of sheets or a roll of sheets. Optionally, the aerosol-forming substrate may include or be in the form of a plurality of fragments. Optionally, the aerosol-forming substrate may be in the form of a tube.

[0079] Optionally, each sheet or strip has a thickness of at least 5, 10, 20, 50, 100, 150, or 200 microns. Optionally, each sheet or strip has a thickness of 2000, 1000, 500, 400, 300, or 250 microns or less. Optionally, each sheet or strip has a thickness of 100 to 350 microns, or 150 to 300 microns.

[0080] Optionally, the sheet or strip or each thereof has a width of at least 100, 200, 500, or 1000 microns. Optionally, the sheet or strip or each thereof has a width of 2000, 1000, 500, 400, 300, 250, or 200 microns or less. Optionally, the sheet or strip or each thereof has a width of 100 to 2000 microns, or 500 to 1000 microns, or 600 to 1000 microns.

[0081] Optionally, the sheet or strip, or each thereof has a length of at least 100, 200, 500, 1000, 2000, or 3000 microns. Optionally, the sheet or strip, or each thereof has a length of 6000, 5000, 3000, 2000, 1000, 500, or 200 microns or less. Optionally, the sheet or strip, or each thereof has a length of 100 to 6000 microns, or 500 to 5000 microns, or 1000 to 4000 microns.

[0082] Optionally, the sheet or strip, or each thereof has a basis weight of at least 20, 50, or 100 g / m 2 ². Optionally, the sheet or strip, or each thereof has a basis weight of 300 g / m 2 ² or less. Optionally, the sheet or strip, or each thereof has a basis weight of 20 to 300 g / m 2 , 50 to 250 g / m 2 , or 100 to 250 g / m 2 ².

[0083] Optionally, the sheet or strip, or each thereof has a density of at least 0.1, 0.2, 0.3, or 0.5 g / m 3 ³. Optionally, the sheet or strip, or each thereof has a density of 2, 1.5, 1.2, or 1 g / m 3 ³ or less. Optionally, the sheet or strip, or each thereof has a density of 0.1 to 2 g / m 3 , 0.2 to 2 g / m 3 , 0.3 to 2 g / m 3, 0.3~1.5g / m 3 , or 0.3~1.2g / m 3 It has a density of .

[0084] If the substrate includes an assembly of one or more sheets, the assembly of sheets or each of them may have a width of at least about 1, 2, 5, 10, 25, 50, or 100 mm.

[0085] Optionally, the aerosol-forming substrate comprises an aerosol-forming body and expanded graphite particles constituting 3% to 90% by weight of a second material on a dry weight basis, wherein the second material is configured to generate an aerosol when heated to a temperature of 120°C to 395°C. Optionally, the aerosol-forming substrate comprises tobacco, an aerosol-forming body, and expanded graphite particles constituting 3% to 90% by weight of a second material on a dry weight basis, wherein the second material is configured to generate an aerosol when heated to a temperature of 120°C to 395°C. Optionally, the aerosol-forming substrate is a thermally conductive, homogenized tobacco material containing expanded graphite particles, further comprising fibers and a binder.

[0086] Optionally, the aerosol-forming substrate does not contain tobacco, for example, the substrate is a thermally conductive, tobacco-free material containing expanded graphite particles, and further comprises fibers and a binder.

[0087] According to a second aspect of this disclosure, an aerosol-generating article is also provided.

[0088] The article may comprise the aerosol-forming substrate described above, for example, the aerosol-forming substrate according to the first embodiment.

[0089] Optionally, the article is in the form of a rod and comprises a plurality of components including an aerosol-forming substrate assembled within a wrapper or casing, or a combination of aerosol-forming substrates.

[0090] Optionally, the aerosol generating article includes a front plug. Optionally, the aerosol generating article includes a first hollow tube, for example, a first hollow acetate tube. Optionally, the aerosol generating article includes a second hollow tube, for example, a second hollow acetate tube. Optionally, the second hollow tube includes one or more vents. Optionally, the aerosol generating article includes a mouth-side plug filter. Optionally, the aerosol generating article includes a wrapper, for example, a paper wrapper.

[0091] Optionally, the front plug is located at the upstream end of the article. Optionally, the aerosol-forming substrate is located downstream of the front plug. Optionally, the first hollow tube is located downstream of the aerosol-forming substrate. Optionally, the second hollow tube is located downstream of the first hollow tube. Optionally, the mouth-side plug filter is located downstream of one or both of the first and second hollow tubes. Optionally, the mouth-side plug filter is located at the downstream end of the article. Optionally, the downstream end of the article, also called the mouth end of the article, may be configured to be inserted into the user's mouth. The user may, for example, directly inhale the mouth end of the article.

[0092] Optionally, the front plug, aerosol-forming substrate, one or both of the first and second hollow tubes, and the mouth plug filter are surrounded by a wrapper, such as a paper wrapper.

[0093] Optionally, the front plug has a length of 2-10 mm, 3-8 mm, or 4-6 mm, for example, about 5 mm. Optionally, the aerosol-forming substrate has a length of 5-20 mm, 8-15 mm, or 10-15 mm, for example, about 12 mm. Optionally, the first hollow tube has a length of 2-20 mm, 5-15 mm, or 5-10 mm, for example, about 8 mm. Optionally, the second hollow tube has a length of 2-20 mm, 5-15 mm, or 5-10 mm, for example, about 8 mm. Optionally, the mouth-side plug filter has a length of 5-20 mm, 8-15 mm, or 10-15 mm, for example, about 12 mm. The length of one or more of the front plug, aerosol-forming substrate, first hollow tube, second hollow tube, and mouth-side plug filter may extend in the longitudinal direction.

[0094] One or more of the front plug, aerosol-forming substrate, first hollow tube, second hollow tube, and mouth plug filter may be substantially cylindrical in shape, for example, a straight cylinder.

[0095] A third aspect of this disclosure provides an aerosol generating system.

[0096] The system may comprise an aerosol-generating article and an electro-aerosol generator. The article may be one of the articles described above, for example, an article according to the second embodiment.

[0097] Optionally, the electric aerosol generator may be configured to resistively heat the aerosol generating article during use.

[0098] Optionally, the electric aerosol generator is configured to induce heating of the aerosol generating article, for example, the aerosol-forming substrate of the aerosol generating article, during use.

[0099] The present disclosure provides a method for forming an aerosol-forming substrate, such as the substrate described above, for example, the substrate according to the first embodiment. The method may include forming a slurry comprising one or more or all of expanded graphite particles, aerosol-forming materials, fibers, and binders. The method may include casting and drying the slurry to form an aerosol-forming substrate or a precursor for forming an aerosol-forming substrate.

[0100] Accordingly, according to a fourth aspect of this disclosure, a method is provided for forming an aerosol-forming substrate, such as the substrate described above, including the substrate according to the first aspect. The method is as follows: Forming a slurry containing expanded graphite particles, aerosol formers, fibers, and a binder, The process includes casting and drying a slurry to form an aerosol-forming substrate or a precursor for forming an aerosol-forming substrate.

[0101] Optionally, the slurry may contain water. Optionally, the slurry may contain 20-90, 30-90, 40-90, 40-85, 50-80, 60-80, or 60-75% by weight of water.

[0102] Optionally, the slurry contains an acid. Optionally, the acid contains or consists of one or more of fumaric acid, lactic acid, benzoic acid, and levulinic acid.

[0103] Optionally, the slurry contains nicotine.

[0104] Optionally, forming a slurry may include forming a first mixture. The first mixture may contain an aerosol-forming agent. The first mixture may contain fibers. The first mixture may contain water. The first mixture may contain an acid. The first mixture may contain nicotine. Forming a slurry may also include forming a second mixture. The second mixture may contain expanded graphite particles. The second mixture may contain a binder. Forming a slurry may also include adding the second mixture to the first mixture to form a combined mixture.

[0105] Therefore, forming a slurry is To form a first mixture comprising an aerosol-forming material, fiber, water, optionally an acid, and optionally nicotine, To form a second mixture containing expanded graphite particles and a binder, This may include adding a second mixture to a first mixture to form a combined mixture.

[0106] The combined mixture can then be formed into a slurry, for example, by mixing.

[0107] Optionally, forming a first mixture includes providing an aerosol-forming body or a solution containing an aerosol-forming body and nicotine.

[0108] Optionally, forming a first mixture involves adding an acid to an aerosol-forming agent, or a solution containing an aerosol-forming agent and nicotine, to form a first premixture.

[0109] Optionally, forming a first mixture involves adding water to an aerosol-forming agent, or a solution containing an aerosol-forming agent and nicotine, or to the first premixture to form a second premixture.

[0110] Optionally, forming a first mixture involves adding fibers to a second premixture.

[0111] Optionally, forming a second mixture involves mixing expanded graphite particles with a binder.

[0112] Optionally, the method, for example, the step of forming a slurry, includes a first mixing of the combined mixture. Optionally, the first mixing is carried out under a first pressure of 500, 400, 300, 250, or 200 mbar or less. Optionally, the first mixing is carried out for 1 to 10 minutes, 2 to 8 minutes, or 3 to 6 minutes, for example, about 4 minutes.

[0113] Optionally, the method, for example, the step of forming a slurry, includes a second mixing after the first mixing. Optionally, the second mixing is carried out under a second pressure lower than the first pressure. Optionally, the second pressure is 500, 400, 300, 200, 150, or 100 mbar or less. Optionally, the second mixing is carried out for 5-120 seconds, 5-80 seconds, 5-40 seconds, or 10-30 seconds, for example, about 20 seconds.

[0114] Optionally, casting a slurry includes casting the slurry onto a flat support, such as a flat steel support.

[0115] Optionally, after casting the slurry and before drying the slurry, the method includes setting the slurry thickness, for example, setting the slurry thickness to 100-1200 microns, 200-1000 microns, 300-900 microns, 500-700 microns, or, for example, about 600 microns.

[0116] Optionally, drying the slurry involves providing a flow of 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 100–160 degrees Celsius or 120–140 degrees Celsius. Optionally, the gas flow is provided for 1–10 minutes or 2–5 minutes. Optionally, drying the slurry involves drying the slurry until it has a water content of 1–20, 2–15, 2–10, or 3–7% by weight.

[0117] Optionally, the slurry is dried to form a precursor for forming an aerosol-forming substrate, the precursor being a sheet of aerosol-forming material. Optionally, the method includes cutting the sheet of aerosol-forming material.

[0118] As will be understood by those skilled in the art who have read this disclosure, features described herein in relation to one embodiment may be applicable to any other embodiment. For example, features described in relation to the combined aerosol-forming substrate of the second embodiment, or in relation to the first and second materials of the combined aerosol-forming substrate of the second embodiment, may be applicable to the aerosol-forming substrate of the first embodiment, and vice versa.

[0119] As used herein, the term “aerosol-forming substrate” may refer to a substrate having the ability to release aerosols or volatile compounds that can form aerosols. Such volatile compounds may be released by heating the aerosol-forming substrate. The aerosol-forming substrate may include aerosol-forming materials. The aerosol-forming substrate may be adsorbed, coated, impregnated, or otherwise loaded onto a carrier or support. Conveniently, the aerosol-forming substrate may be part of an aerosol-generating article or a smoking article.

[0120] As used herein, the term “thermally conductive particles” may refer to particles having a thermal conductivity greater than 1 W / (MK) in at least one direction at 25 degrees Celsius, such as in all directions at 25 degrees Celsius. The particles may exhibit anisotropic or isotropic thermal conductivity.

[0121] As used herein, the term “stretched graphite” may refer to a graphite-based material or a material having a graphite-like structure. Stretched graphite may have carbon layers (e.g., similar to graphite) where the spacing between carbon layers is greater than that found between carbon layers in ordinary graphite. Stretched graphite may have carbon layers with elements or compounds interposed in the spaces between carbon layers.

[0122] As used herein, the term “particle size” may refer to a single dimension and may be used to characterize a given particle size. The dimension may also be the diameter of a spherical particle occupying the same volume as a given particle. All particle sizes and particle size distributions herein can be obtained using standard laser diffraction techniques. The particle sizes and particle size distributions described herein can be obtained using commercially available sensors, such as Sympatec’s HELOS laser diffraction sensor.

[0123] Where used herein, unless otherwise specified, the term “density” may be used to mean true density. Thus, unless otherwise specified, the density of a powder or a group of particles may refer to the true density of the powder or the group of particles (rather than the bulk density of the powder or the group of particles, which can vary considerably depending on how the powder or the group of particles is handled). The measurement of true density can be performed using many 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 the powder being weighed in a container of known volume (pycnometer). The pycnometer is then filled with a fluid of known density, in which the powder is not available. The volume of the powder is determined by the difference between the volume indicated by the pycnometer and the volume to which the liquid has been added (i.e., the volume of displaced air).

[0124] As used herein, the term "aerosol-generating article" may refer to an article that can generate or release aerosols, for example, when heated.

[0125] As used herein, the term “long axis direction” may refer to the direction extending between the downstream or proximal end and the upstream or distal end of a component such as an aerosol-forming substrate or aerosol-generating article.

[0126] As mentioned above, the term "transverse direction" can refer to a direction perpendicular to the longitudinal axis.

[0127] As used herein, the term “aerosol generator” may refer to a device used in conjunction with an aerosol-generating article to enable the generation or release of an aerosol.

[0128] As used herein, the term “assembly of sheets” may refer to an aerosol-forming substrate, or a sheet of an aerosol-generating article that is spirally wound, folded, or otherwise compressed or shrunk substantially transversely to the longitudinal axis of the aerosol-forming substrate or the aerosol-generating article.

[0129] As used herein, the term “sheet” may refer to a substantially planar, thin layered element having a width and length substantially greater than at least 2, 3, 5, 10, 20, or 50 times its thickness.

[0130] As used herein, the term “fiber strip” may refer to a substantially planar, thin-layered element having a width and length substantially greater than its thickness. The width of a fiber strip may be greater than its thickness, for example, at least 2, 3, 5, or 10 times its thickness. The length of a fiber strip may be greater than its width, for example, at least 2, 3, 5, or 10 times its width.

[0131] As used herein, the term “aerosol-forming material” may refer to any suitable known compound or mixture of compounds that facilitates aerosol formation during use. The aerosol may be high-density and stable. The aerosol may be substantially resistant to thermal decomposition at the operating temperature of the aerosol-forming substrate or aerosol-generating article.

[0132] As used herein, the term “aerosol cooling element” may refer to a component of an aerosol-generating article located downstream of an aerosol-forming substrate, such that, during use, an aerosol formed by the substrate or by volatile compounds released from the aerosol-forming substrate passes through the aerosol cooling element and is cooled by the aerosol-generating element before being inhaled by the user.

[0133] As used herein, the term "rod" may generally refer to a cylindrical element, for example, a right cylindrical element with a substantially circular, oval, or elliptical cross-section.

[0134] As used herein, the term “crimp” may refer to a sheet having one or more ridges or undulations. The ridges or undulations may be substantially parallel. If present within a component of an aerosol-generating article, the ridges or undulations may extend along the longitudinal axis relative to the aerosol-generating article.

[0135] As used herein, the term “ventilation level” may refer to the volume ratio of the airflow entering the aerosol-generating article through the ventilation zone (ventilation airflow) to the sum of the aerosol airflow and the ventilation airflow. A higher ventilation level results in greater dilution of the aerosol flow delivered to the consumer. [Examples]

[0136] The present invention is defined in the claims. However, a non-exclusive list of non-limiting embodiments is provided below. One or more features of these embodiments may be combined with one or more features of other embodiments, forms, or aspects described herein.

[0137] Example 1. An aerosol-forming substrate for use in an aerosol-generating article, comprising expanded graphite particles. Example 2. For example, an aerosol-forming substrate according to Example 1, further comprising an aerosol-forming material such as an aerosol-forming body. Example 3. An aerosol-forming substrate according to Example 1 or 2, wherein expanded graphite particles constitute 80, 50, 20, 10, or 5% by weight or less of the aerosol-forming substrate. Example 4. An aerosol-forming substrate according to any of Examples 1 to 3, wherein expanded graphite particles constitute 0.1, 0.2, 0.5, 1, 2, 3, 5, 10, 20, or 50% or more by weight of the aerosol-forming substrate. Example 5. An aerosol-forming substrate according to any of Examples 1 to 4, wherein expanded graphite particles constitute 1 to 20, 2 to 20, 3 to 20, 5 to 20, 3 to 15, 5 to 15, or 3 to 10% by weight of the aerosol-forming substrate. Example 6. Based on dry weight, 1-90% by weight of expanded graphite particles, 7-60% by weight of an aerosol-forming material, 2-20% by weight of fiber, An aerosol-forming substrate according to any of Examples 1 to 5, comprising 2 to 10% by weight of a binder. Example 7. Based on dry weight, 10-90% by weight of expanded graphite particles, 7-60% by weight of an aerosol-forming material, 2-20% by weight of fiber, An aerosol-forming substrate according to any of Examples 1 to 6, comprising 2 to 10% by weight of a binder. Example 8. An aerosol-forming substrate according to any of Examples 1 to 7, wherein the expanded graphite particles have a thermal conductivity of at least 0.3, 0.5, 1, 2, 5, or 10 W / (mK) in at least one direction at 25 degrees Celsius. Example 9. Based on dry weight, 1-90% by weight of expanded graphite particles, 7-60% by weight of an aerosol-forming material, 2-20% by weight of fiber, It contains 2-10% by weight of a binder, An aerosol-forming substrate according to any of Examples 1 to 8, wherein the aerosol-forming substrate has a thermal conductivity of at least 0.22 W / (mK) in at least one direction at 25 degrees Celsius. Example 10. Based on dry weight, 10-90% by weight of expanded graphite particles, 7-60% by weight of an aerosol-forming material, 2-20% by weight of fiber, It contains 2-10% by weight of a binder, An aerosol-forming substrate according to any of Examples 1 to 9, wherein the aerosol-forming substrate has a thermal conductivity of at least 0.22 W / (mK) in at least one direction at 25 degrees Celsius. Example 11. Aerosol-forming substrate according to any of Examples 1 to 10, containing 1 to 15% by weight of expanded graphite particles. Example 12. An aerosol-forming substrate according to any of Examples 1 to 11, containing 3 to 6% by weight of expanded graphite particles. Example 13. An aerosol-forming substrate according to any of Examples 1 to 12, wherein the expanded graphite particles have a particle size distribution having several D10 particle sizes, and the several D10 particle sizes are at least 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 microns. Example 14. An aerosol-forming substrate according to any of Examples 1 to 13, wherein the expanded graphite particles have a particle size distribution having several D10 particle sizes, and the several D10 particle sizes are 1,000, 500, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, or 0.2 microns or less. Example 15. An aerosol-forming substrate according to any of Examples 1 to 14, wherein the expanded graphite particles have a particle size distribution having several D50 particle sizes, and the several D50 particle size is at least 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 microns. Example 16. An aerosol-forming substrate according to any of Examples 1 to 15, wherein the expanded graphite particles have a particle size distribution with several D50 particle sizes, and the several D50 particle sizes are 1,000, 500, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, or 0.2 microns or less. Example 17. An aerosol-forming substrate according to any of Examples 1 to 16, wherein the expanded graphite particles have a particle size distribution having several D90 particle size, and the several D90 particle size is at least 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 microns. Example 18. An aerosol-forming substrate according to any of Examples 1 to 17, wherein the expanded graphite particles have a particle size distribution with several D90 particle sizes, and the several D90 particle sizes are 1,000, 500, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, or 0.2 microns or less. Example 19. An aerosol-forming substrate according to any of Examples 1 to 18, wherein the expanded graphite particles have a particle size distribution having a volume D10 particle size, and the volume D10 particle size is at least 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 microns. Example 20. An aerosol-forming substrate according to any of Examples 1 to 19, wherein the expanded graphite particles have a particle size distribution having a volume D10 particle size, and the volume D10 particle size is 1,000, 500, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, or 0.2 microns or less. Example 21. An aerosol-forming substrate according to any of Examples 1 to 20, wherein the expanded graphite particles have a particle size distribution having a volume D50 particle size, and the volume D50 particle size is at least 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 microns. Example 22. An aerosol-forming substrate according to any of Examples 1 to 21, wherein the expanded graphite particles have a particle size distribution having a volume D50 particle size, and the volume D50 particle size is 1,000, 500, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, or 0.2 microns or less. Example 23. An aerosol-forming substrate according to any of Examples 1 to 22, wherein the expanded graphite particles have a particle size distribution having a volume D90 particle size, and the volume D90 particle size is at least 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 microns. Example 24. An aerosol-forming substrate according to any of Examples 1 to 23, wherein the expanded graphite particles have a particle size distribution having a volume D90 particle size, and the volume D90 particle size is 1,000, 500, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, or 0.2 microns or less. Example 25. The expanded graphite particles have a particle size distribution with several D10 particle size, several D90 particle size, volume D10 particle size, and volume D90 particle size. The particle size of D90 is 50, 40, 30, 20, 10, or 5 times or less than the particle size of D10. Alternatively, the volume D10 particle size is 50, 40, 30, 20, 10, or 5 times or less the volume D10 particle size. Alternatively, an aerosol-forming substrate according to any of Examples 1 to 24, wherein the particle size of several D90 is 50, 40, 30, 20, 10, or 5 times or less the particle size of several D10, and the volume D10 particle size is 50, 40, 30, 20, 10, or 5 times or less the volume D10 particle size. Example 26. An aerosol-forming substrate according to any of Examples 1 to 26, wherein the expanded graphite particles have a particle size distribution, and one or both of the several D10 particle size and volume D1 particle size are 1 to 20 microns. Example 27. An aerosol-forming substrate according to any of Examples 1 to 26, wherein the expanded graphite particles have a particle size distribution, and one or both of the number D90 particle size and volume D90 particle size are 50 to 300 microns or 50 to 200 microns. Example 28. An aerosol-forming substrate according to any of Examples 1 to 27, wherein each expanded graphite particle has a particle size of at least 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 microns. Example 29. An aerosol-forming substrate according to any of Examples 1 to 28, wherein each thermally conductive particle has a particle size of 1,000, 500, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, or 0.2 microns or less. Example 30. An aerosol-forming substrate according to any of Examples 1 to 29, wherein each expanded graphite particle has three mutually orthogonal dimensions, and the largest of the three dimensions is 10, 8, 5, 3, or 2 times greater than one or both of the smallest of the three dimensions and the second largest of the three dimensions. Example 31. An aerosol-forming substrate according to any of Examples 1 to 30, wherein each of the expanded graphite particles is substantially spherical. Example 32. An aerosol-forming substrate according to any of Examples 1 to 31, comprising at least 10, 20, 50, 100, 200, 500, or 1000 expanded graphite particles. Example 33. Aerosol-forming substrate according to any of Examples 1 to 32, wherein the substrate contains at least 20, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or 85% by weight of expanded graphite particles on a dry weight basis. Example 34. Aerosol-forming substrate according to any of Examples 1 to 33, wherein the substrate contains expanded graphite particles in an amount of 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, or 15% by weight or less, on a dry weight basis. Example 35. The base material is based on dry weight and is available in the following ranges: 1-95, 4-94, 10-90, 20-90, 30-90, 40-90, 50-90, 60-90, 70-90, 80-90, 10-80, 20-80, 30-80, 40-80, 50-80, 60-80, 70-80, 10-70, 20-70, 30-70, 40-70, 50- Aerosol-forming substrate according to any of Examples 1 to 34, comprising expanded graphite particles in a quantity of 70, 60-70, 10-60, 20-60, 30-60, 40-60, 50-60, 10-50, 20-50, 30-50, 40-50, 10-40, 20-40, 30-40, 10-30, 20-30, or 10-20% by weight. Example 36. Aerosol-forming substrate according to any of Examples 1 to 35, wherein the substrate contains at least 10, 15, 20, 25, 30, 35, 40, 45, 50, or 55% by weight of an aerosol-forming material, on a dry weight basis. Example 37. An aerosol-forming substrate according to any of Examples 1 to 36, wherein the substrate contains an aerosol-forming material in an amount of 55, 50, 45, 40, 35, 30, 25, 20, or 15% by weight or less, on a dry weight basis. Example 38. An aerosol-forming substrate according to any of Examples 1 to 37, wherein the substrate contains 7-60, 10-60, 20-60, 30-60, 40-60, 50-60, 7-50, 10-50, 20-50, 30-50, 40-50, 7-40, 10-40, 20-40, 30-40, 7-30, 10-30, 20-30, 7-20, 10-20, or 7-10% by weight of aerosol-forming material, and particularly preferably contains 15-25% by weight of aerosol-forming material. Example 39. An aerosol-forming substrate according to any of Examples 1 to 38, wherein the aerosol-forming body contains or consists of one or more of the following: 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 tri-acetates, and aliphatic esters or mono, di-, or polycarboxylic acids (such as dimethyldodecanediol and dimethyl tetradecanediol). Example 40. An aerosol-forming substrate according to any of Examples 1 to 39, wherein the aerosol-forming substrate contains one or both of glycerin and glycerol. Example 41. Aerosol-forming substrate according to any of Examples 1 to 40, wherein the substrate contains at least 2, 4, 6, 8, 10, 12, 14, 16, or 18% by weight of fibers on a dry weight basis. Example 42. Aerosol-forming substrate according to any of Examples 1 to 41, wherein the substrate contains 20, 18, 16, 14, 12, 10, 8, 6, or 4% or less of fibers by dry weight. Example 43. The base material, based on dry weight, is available in the following quantities: 4-20, 6-20, 8-20, 10-20, 12-20, 14-20, 16-20, 18-20, 2-18, 4-18, 6-18, 8-18, 10-18, 12-18, 14-18, 16-18, 2-16, 4-16, 6-16, 8-16, 10-16, 12-16, 14-16, 2-14, 4-1 Aerosol-forming substrate according to any of Examples 1 to 42, comprising 4, 6-14, 8-14, 10-14, 12-14, 2-12, 4-12, 6-12, 8-12, 10-12, 2-10, 4-10, 6-10, 8-10, 2-8, 4-8, 6-8, 2-6, 4-6, or 2-4% by weight of fibers, preferably 2-10% by weight of fibers. Example 44. An aerosol-forming substrate according to any of Examples 1 to 43, wherein the fibers are cellulose fibers. Example 45. An aerosol-forming substrate according to any of Examples 1 to 44, wherein each fiber has three mutually orthogonal dimensions, and the largest of the three dimensions is at least 1.5, 2, 3, 5, 10, or 20 times larger than the smallest of the three dimensions. Example 46. An aerosol-forming substrate according to any of Examples 1 to 45, wherein each fiber has three mutually orthogonal dimensions, and the largest of the three dimensions is at least 1.5, 2, 3, 5, 10, or 20 times larger than the second largest of the three dimensions. Example 47. Aerosol-forming substrate according to any of Examples 1 to 46, wherein the substrate contains at least 4, 6, or 8% by weight of a binder on a dry weight basis. Example 48. Aerosol-forming substrate according to any of Examples 1 to 47, wherein the substrate contains 8, 6, or 4% by weight or less of a binder on a dry weight basis. Example 49. Aerosol-forming substrate according to any of Examples 1 to 48, wherein the substrate contains 4-10, 6-10, 8-10, 2-8, 4-8, 6-8, 2-6, 4-6, or 2-4% by weight of a binder, particularly preferably 2-10% by weight of a binder, on a dry weight basis. Example 50. An aerosol-forming substrate according to any of Examples 1 to 49, wherein the binder contains one or both of carboxymethylcellulose or hydroxypropylcellulose, or consists of them. Example 51. An aerosol-forming substrate according to any of Examples 1 to 50, wherein the binder contains or consists of one or more gums, such as guar gum. Example 52. An aerosol-forming substrate according to any of Examples 1 to 51, wherein expanded graphite particles are substantially homogeneously distributed throughout the entire aerosol-forming substrate. Example 53. An aerosol-forming substrate according to any of Examples 1 to 52, wherein the aerosol-forming material is substantially homogeneously distributed throughout the entire aerosol-forming substrate. Example 54. An aerosol-forming substrate according to any of Examples 1 to 53, wherein the fibers are substantially homogeneously distributed throughout the entire aerosol-forming substrate. Example 55. An aerosol-forming substrate according to any of Examples 1 to 54, wherein the binder is substantially homogeneously distributed throughout the entire aerosol-forming substrate. Example 56. An aerosol-forming substrate according to any of Examples 1 to 55, wherein the substrate contains nicotine. Example 57. Aerosol-forming substrate according to Example 56, wherein the substrate contains at least 0.01, 1, 2, 3, or 4% by weight of nicotine on a dry weight basis. Example 58. Aerosol-forming substrate according to any of Examples 56-57, wherein the substrate contains 5, 4, 3, 2, or 1% by weight or less of nicotine on a dry weight basis. Example 59. Aerosol-forming substrate according to any of Examples 1 to 58, wherein the substrate contains nicotine in amounts of 0.01-5, 1-5, 2-5, 3-5, 4-5, 0.01-4, 1-4, 2-4, 3-4, 0.01-3, 1-3, 2-3, 0.01-2, 1-2, or 0.01-1% by weight, particularly preferably 0.5-4% by weight, on a dry weight basis. Example 60. An aerosol-forming substrate according to any of Examples 56 to 58, wherein nicotine is substantially homogeneously distributed throughout the entire aerosol-forming substrate. Example 61. A substrate comprising an acid, an aerosol-forming substrate according to any of Examples 1 to 60. Example 62. An aerosol-forming substrate according to Example 61, wherein the substrate contains at least 0.01, 1, or 2% by weight of acid on a dry weight basis. Example 63. Aerosol-forming substrate according to any of Examples 61 to 62, wherein the substrate contains 3, 2, or 1% by weight or less of acid on a dry weight basis. Example 64. Aerosol-forming substrate according to any of Examples 61 to 63, wherein the substrate contains 0.01 to 3, 1 to 3, 2 to 3, 0.01 to 2, 1 to 2, or 0.01 to 1% by weight of acid, particularly preferably 0.5 to 5% by weight of acid, on a dry weight basis. Example 65. An aerosol-forming substrate according to any of Examples 61 to 64, wherein the acid contains one or more of fumaric acid, lactic acid, benzoic acid, and levulinic acid, or consists of these. Example 66. An aerosol-forming substrate according to any of Examples 61 to 65, wherein the acid is substantially homogeneously distributed throughout the entire aerosol-forming substrate. Example 67. an aerosol-forming substrate according to any of Examples 1 to 66, wherein the substrate contains at least one plant. Example 68. Aerosol-forming substrate according to Example 67, wherein the substrate contains at least 0.01, 1, 2, 5, 10, or 1% by weight of at least one plant, on a dry weight basis. Example 69. Aerosol-forming substrate according to any of Examples 67-68, wherein the substrate contains at least one plant in an amount of 20, 15, 10, 5, 2, or 1% by weight or less, on a dry weight basis. Example 70. Aerosol-forming substrate according to any of Examples 67 to 69, wherein the substrate contains, on a dry weight basis, at least one plant in amounts of 0.01-20, 1-20, 2-20, 5-20, 10-20, 15-20, 0.01-15, 1-15, 2-15, 5-15, 10-15, 0.01-10, 1-10, 2-10, 5-10, 0.01-5, 1-5, 2-5, 0.01-2, 1-2, and 0.01-1% by weight, particularly preferably at least one plant in amounts of 1-15% by weight. Example 71. Aerosol-forming substrate according to any of Examples 67-70, wherein at least one plant comprises one or both of clove and rosmanus, or consists of them. Example 72. An aerosol-forming substrate according to any of Examples 67 to 71, wherein at least one plant is substantially homogeneously distributed throughout the aerosol-forming substrate. Example 73. An aerosol-forming substrate according to any of Examples 1 to 72, wherein the substrate contains at least one flavoring agent. Example 74. An aerosol-forming substrate according to Example 73, wherein the substrate contains at least 0.1, 1, 2, or 5% by weight of at least one flavoring agent on a dry weight basis. Example 75. Aerosol-forming substrate according to any of Examples 73 to 74, wherein the substrate contains at least one flavoring agent in an amount of 10, 5, 2, or 1% by weight on a dry weight basis. Example 76. Aerosol-forming substrate according to any of Examples 73 to 75, wherein the substrate contains, on a dry weight basis, at least one flavoring agent in amounts 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% by weight, particularly preferably at least one flavoring agent in amounts of 0.1 to 5% by weight. Example 77. An aerosol-forming substrate according to any of Examples 73 to 76, wherein at least one flavoring agent is present as a coating, for example, a coating on one or more other components of the aerosol-forming substrate. Example 78. An aerosol-forming substrate according to any of Examples 73 to 77, wherein at least one flavoring agent is substantially homogeneously distributed throughout the entire aerosol-forming substrate. Example 79. An aerosol-forming substrate according to any of Examples 1 to 78, wherein the aerosol-forming substrate contains one or more organic materials such as tobacco. Example 80. The organic material is an aerosol-forming substrate according to any of Examples 1 to 79, comprising one or more of the following: medicinal herb leaves, tobacco leaves, tobacco stem fragments, reconstituted tobacco, homogenized tobacco, extruded tobacco, and puffed tobacco. Example 81. An aerosol-forming substrate according to any of Examples 1 to 80, wherein the organic material is substantially homogeneously distributed throughout the entire aerosol-forming substrate. Example 82. An aerosol-forming substrate according to any of Examples 1 to 81, wherein the aerosol-forming substrate is a tobacco-free aerosol-forming substrate. Example 83. An aerosol-forming substrate according to any of Examples 1 to 82, wherein some or each of the expanded graphite particles acts as a susceptor material. Example 84. An aerosol-forming substrate according to any of Examples 1 to 83, wherein the aerosol-forming substrate has a thermal conductivity of at least 0.15, 0.2, 0.22, 0.3, 0.4, 0.5, 0.75, 1, 1.25, or 1.5 W / (mK) at 25 degrees Celsius in at least one direction or in all directions. Example 85. The aerosol-forming substrate is 1500, 1050, 1000, 950, 900, 850, 800, 850, 800, 750, 700, or 650 kg / m³ 3 Aerosol-forming substrate having a density less than 1, according to any of Examples 1 to 84. Example 86. Aerosol-forming substrate, 500-900 kg / m³ 3 , or 600-800 kg / m 3 An aerosol-forming substrate having the density of any of Examples 1 to 85. Example 87. An aerosol-forming substrate according to any of Examples 1 to 86, wherein the aerosol-forming substrate has a water content of 1 to 20 or 3 to 15% by weight. Example 88. Aerosol-forming substrate according to any of Examples 1 to 87, wherein the aerosol-forming substrate contains 1 to 20 or 3 to 15% by weight of water. Example 89. An aerosol-forming substrate according to any of Examples 1 to 88, wherein the aerosol-forming substrate comprises one or more of the following: cut filler, powder particles, granules, pellets, fragments, spaghetti, slivers, sheets, sheet rolls, sheet aggregates, or tubes, or is in the form thereof. Example 90. An aerosol-forming substrate according to any of Examples 1 to 89, wherein the aerosol-forming substrate comprises one or more sheets or fragments, or is in the form of such sheets or fragments. Example 91. An aerosol-forming substrate according to any of Examples 1 to 90, wherein the aerosol-forming substrate comprises or is in the form of an aggregate of one or more sheets. Example 92. An aerosol-forming substrate according to Example 91, wherein the aggregate of sheets, or each of them, has a width of at least about 5, 10, 25, 50, or 100 mm. Example 93. An aerosol-forming substrate according to any of Examples 1 to 92, wherein the aerosol-forming substrate comprises a plurality of fragments or is in the form of such fragments. Example 94. An aerosol-forming substrate according to any of Example 93, wherein each of the multiple strips has a length of at least about 3, 5, or 10 mm. Example 95. An aerosol-forming substrate according to any of Examples 93-94, wherein each of the multiple flakes has a width of approximately 3, 2, or less than 1 mm. Example 96. Aerosol-forming substrate according to any of Examples 90 to 95, wherein each sheet or strip, or each thereof, has a thickness of at least 100, 150, or 200 microns. Example 97. Aerosol-forming substrate according to any of Examples 90 to 96, wherein each sheet or strip, or each thereof, has a thickness of 300 or 250 microns or less. Example 98. Aerosol-forming substrate according to any of Examples 90 to 97, wherein each sheet or strip, or each thereof, has a thickness of 100 to 300 microns, 150 to 250 microns, or 200 to 250 microns. Example 99. Each sheet or strip contains at least 20, 50, or 100 g / m² of material. 2An aerosol-forming substrate having the basis weight of any of Examples 90 to 98. Example 100. Each sheet or strip, or each of them, contains 300g / m². 2 An aerosol-forming substrate according to any of Examples 90 to 99, having the following basis weights. Example 101. Each sheet or strip contains 20-300 g / m². 2 50-250g / m 2 , or 100-250g / m 2 An aerosol-forming substrate having the basis weight of any of Examples 90 to 100. Example 102. Each sheet or strip contains at least 0.1, 0.2, 0.3, or 0.5 g / m². 3 An aerosol-forming substrate having the density of any of Examples 90 to 101. Example 103. Each sheet or piece, or each of them, contains 2, 1.5, 1.2, or 1 g / m². 3 Aerosol-forming substrate according to any of Examples 90 to 102, having the following densities. Example 104. Each sheet or piece contains 0.1-2 g / m². 2 , 0.2~2g / m 2 , 0.3~2g / m 2 , 0.3~1.5g / m 2 , or 0.3~1.2g / m 3 An aerosol-forming substrate having the density of any of Examples 90 to 103. Example 105. An aerosol-generating article comprising an aerosol-forming substrate as defined in any of Examples 1 to 104. Example 106. An aerosol generating article according to Example 105, wherein the article is in the form of a rod and comprises a plurality of components including an aerosol-forming substrate assembled within a wrapper or casing. Example 107. An aerosol generating article comprising an assembly or roll of sheets of an aerosol-forming substrate according to any of Examples 1 to 106. Example 108. An aerosol generating article according to any of Examples 105 to 107, wherein the aerosol generating article is equipped with a front plug. Example 109. An aerosol generating article according to any of Examples 105 to 108, wherein the aerosol generating article comprises a first hollow tube, for example, a first hollow acetate tube. Example 110. An aerosol generating article according to Example 109, wherein the aerosol generating article comprises a second hollow tube, for example, a second hollow acetate tube. Example 111. An aerosol generating article according to Example 110, wherein the second hollow tube includes one or more ventilation holes. Example 112. An aerosol generating article according to any of Examples 105 to 111, wherein the aerosol generating article is equipped with a mouth-side plug filter. Example 113. An aerosol-generating article according to any of Examples 105 to 112, wherein the aerosol-generating article includes a wrapper, such as a paper wrapper. Example 114. An aerosol generating article according to any of Examples 105 to 113, comprising a front plug, an aerosol forming substrate disposed downstream of the front plug, a first hollow tube disposed downstream of the aerosol forming substrate, a second hollow tube disposed downstream of the first hollow tube, and a mouth-side plug filter disposed downstream of the second hollow tube. Example 115. An aerosol generating article according to Example 114, in which a front plug, an aerosol-forming substrate, a first hollow tube, a second hollow tube, and a mouth-side plug filter are surrounded by a wrapper, such as a paper wrapper. Example 116. An aerosol-generating article according to any of Examples 108-115, wherein the front plug has a length of 2-10, 3-8, or 4-6 mm, for example, about 5 mm. Example 117. An aerosol-generating article according to any of Examples 105 to 116, wherein the aerosol-forming substrate has a length of 5 to 20, 8 to 15, or 10 to 15 mm, for example, about 12 mm. Example 118. An aerosol generating article according to Example 109 or 110-117, in which the first hollow tube has a length of 2-20, 5-15, or 5-10 mm, for example, about 8 mm, as is the case with Example 109. Example 119. An aerosol generating article according to either Example 110 or any of Examples 111-118, wherein the second hollow tube has a length of 2-20, 5-15, or 5-10 mm, for example, about 8 mm, as is dependent on Example 110. Example 120. An aerosol-generating article according to any of Examples 112 or 113-119, in which the mouth-side plug filter has a length of 5-20, 8-15, or 10-15 mm, for example, about 12 mm, as is dependent on Example 112. Example 121. An aerosol generating system comprising an aerosol generating article according to any of Examples 105 to 120 and an electric aerosol generating device. Example 122. An aerosol generation system according to Example 121, wherein the electric aerosol generator is configured to resistively heat the aerosol generating article during use. Example 123. An aerosol generation system according to any one of Examples 121 to 122, wherein the electric aerosol generator is configured to inductively heat an aerosol generating article, for example, the aerosol-forming substrate of the aerosol generating article, when in use. Example 124. A method for forming an aerosol-forming substrate according to any of Examples 1 to 123, for example, any of Examples 1 to 104, wherein the method is Forming a slurry containing expanded graphite particles, aerosol formers, fibers, and a binder, A method comprising casting and drying a slurry to form an aerosol-forming substrate or a precursor for forming an aerosol-forming substrate. Example 125. The method according to Example 124, wherein the slurry contains water. Example 126. The method according to any of Examples 124 to 125, wherein the slurry contains 40-90, 40-85, 50-80, 60-80, or 60-75% by weight of water. Example 127. A method according to any of Examples 124 to 126, wherein the slurry contains an acid such as fumaric acid. Example 128. A method according to any of Examples 124 to 127, wherein the slurry contains nicotine. Example 129. Forming a slurry aerosol former and Fibers and, Water and, Selectively, an acid and To optionally form a first mixture containing nicotine, Expanded graphite particles and, Forming a second mixture containing a binder, A method according to any one of Examples 124 to 128, comprising adding a second mixture to a first mixture to form a combined mixture. Example 130. A method according to Example 129, comprising forming a first mixture to provide an aerosol-forming body or a solution containing an aerosol-forming body and nicotine. Example 131. The method according to Example 130, wherein forming a first mixture involves adding an acid to an aerosol-forming agent or a solution containing an aerosol-forming agent and nicotine to form a first premixture. Example 132. A method according to any of Examples 129 to 131, wherein forming a first mixture involves adding water to an aerosol-forming agent or a solution containing an aerosol-forming agent and nicotine, or to a first premixture, to form a second premixture. Example 133. A method according to any of Examples 129 to 132, wherein forming a first mixture involves adding fibers to a second premixture. Example 134. A method according to any of Examples 129 to 133, wherein forming a second mixture involves mixing expanded graphite particles and a binder. Example 135. A method according to any of Examples 129 to 134, wherein the method includes a first mixing of the combined mixtures. Example 136. The method according to Example 135, wherein the first mixing is performed under a first pressure of 500, 400, 300, 250, or 200 mbar or less. Example 137. The method according to Example 135 or 136, wherein the first mixing is carried out for 1 to 10 minutes, 2 to 8 minutes, or 3 to 6 minutes, for example, about 4 minutes. Example 138. The method is one of the methods in Examples 135 to 137, wherein the method includes a second mixture after the first mixture. Example 139. The method according to Example 138, wherein the second mixing is performed under a second pressure lower than the first pressure. Example 140. The method according to Example 139, wherein the second pressure is 500, 400, 300, 200, 150, or 100 mbar or less. Example 141. The method according to Example 138, 139, or 140, wherein the second mixing is performed for 5-120, 5-80, 5-40, or 10-30 seconds, for example, about 20 seconds. Example 142. A method according to any of Examples 124 to 141, wherein casting the slurry includes casting the slurry onto a flat support, such as a flat steel support. Example 143. A method according to any of Examples 124 to 142, wherein, after casting the slurry and before drying the slurry, the method includes setting the thickness of the slurry, for example, setting the thickness of the slurry to 100 to 1,000 microns, 200 to 900 microns, 300 to 800, 500 to 700 microns, for example, about 600 microns. Example 144. A method according to any one of Examples 124 to 143, wherein drying the slurry involves providing a flow of gas, such as air, on or through the slurry. Example 145. The method according to Example 144, in which the gas flow is heated. Example 146. The method according to Example 145, wherein the gas flow is heated to a temperature of 100-160 degrees Celsius or 120-140 degrees Celsius. Example 147. A method according to any of Examples 144-146, wherein the gas flow is provided for 1-10 minutes or 2-5 minutes. Example 148. A method according to any one of Examples 124 to 147, wherein drying the slurry is performed until the slurry has a water content of 1 to 20, 2 to 15, 2 to 10, or 3 to 7% by weight. Example 149. A method according to any of Examples 124 to 148, wherein drying the slurry forms a precursor for forming an aerosol-forming substrate, and the precursor is a sheet of aerosol-forming material. Example 150. The method according to Example 149, wherein the method includes cutting a sheet of aerosol-forming material.

[0138] Here, we will further describe the examples with reference to the following figures. [Brief explanation of the drawing]

[0139] [Figure 1] Figure 1 shows a schematic cross-sectional view of the first embodiment of the aerosol generating article. [Figure 2] Figure 2 shows a schematic cross-sectional view of a first embodiment of an aerosol generation system equipped with a first aerosol generator. [Figure 3] Figure 3 shows a schematic cross-sectional view of a second embodiment of an aerosol generation system equipped with a second aerosol generator. [Figure 4] Figure 4 shows a schematic cross-sectional view of a second embodiment of the aerosol generating article. [Figure 5] Figure 5 is a bar graph showing the nicotine yield from the aerosol generating article of the first embodiment when used with the aerosol generating device of Figure 2, compared with two alternative aerosol generating articles. [Figure 6] Figure 6 is a bar graph showing the yield of glycerin from the aerosol generating article of the first embodiment when used with the aerosol generating device of Figure 2, compared with two alternative aerosol generating articles. [Figure 7] Figure 7 is a bar graph showing the delivery efficiency of nicotine and glycerin from the aerosol generating article of the first embodiment when used with the aerosol generating device of Figure 2, compared with two alternative aerosol generating articles. [Figure 8] Figure 8 is a bar graph showing the nicotine yield from the aerosol generating article of the first embodiment when used with the aerosol generating device of Figure 3, compared to two alternative aerosol generating articles. [Figure 9] Figure 9 is a bar graph showing the yield of glycerin from the aerosol generating article of the first embodiment when used with the aerosol generating device of Figure 3, compared with two alternative aerosol generating articles. [Figure 10] Figure 10 is a bar graph showing the delivery efficiency of nicotine and glycerin from the aerosol generating article of the first embodiment when used with the aerosol generating device of Figure 3, compared with two alternative aerosol generating articles. [Figure 11]Figure 11 shows an alternative embodiment of an aerosol generating article comprising a heat-enhanced aerosol-forming substrate containing individual elements of the first material and individual elements of the second material. [Modes for carrying out the invention]

[0140] Figure 1 shows a schematic cross-sectional view of a first embodiment of the aerosol generating article 10. The aerosol generating article 10 comprises a rod 12 of an aerosol forming substrate and a downstream section 14 located downstream of the rod 12 of the aerosol forming substrate. Furthermore, the aerosol generating article 10 comprises an upstream section 16 located upstream of the rod 12 of the aerosol forming substrate. Thus, the aerosol generating article 10 extends from the upstream or distal end 18 to the downstream or proximal or oral end 20.

[0141] The aerosol-generating article has a total length of approximately 45 millimeters.

[0142] The downstream section 14 includes a support element 22 located immediately downstream of the rod 12 of the aerosol-forming substrate, and the support element 22 is longitudinally aligned with the rod 12. In the embodiment shown in Figure 1, the upstream end of the support element 22 abuts against the downstream end of the rod 12 of the aerosol-generating substrate. In addition, the downstream section 14 includes an aerosol cooling element 24 located immediately downstream of the support element 22, and the aerosol cooling element 24 is longitudinally aligned with the rod 12 and the support element 22. In the embodiment shown in Figure 1, the upstream end of the aerosol cooling element 24 abuts against the downstream end of the support element 22.

[0143] As will be apparent from the following description, the support element 22 and the aerosol cooling element 24 together define the intermediate hollow section 50 of the aerosol generating article 10. Overall, the intermediate hollow section 50 does not substantially contribute to the overall RTD of the aerosol generating article. The RTD of the intermediate hollow section 26 as a whole is substantially 0 mmH2O.

[0144] The support element 22 may include a first hollow tubular segment 26. The first hollow tubular segment 26 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The first hollow tubular segment 26 defines an internal cavity 28 that extends entirely from the upstream end 30 of the first hollow tubular segment 20 to the downstream end 32 of the first hollow tubular segment 20. The internal cavity 28 is substantially empty, and therefore substantially unrestricted airflow is possible along the internal cavity 28. The first hollow tubular segment 26, and consequently the support element 22, does not substantially contribute to the overall RTD of the aerosol generating article 10. More specifically, the RTD of the first hollow tubular segment 26 (which is substantially the RTD of the support element 22) is substantially 0 mmH2O.

[0145] The first hollow tubular segment 26 has a length of approximately 8 mm, an outer diameter of approximately 7.25 mm, and an inner diameter of approximately 1.9 mm (D FTS ) has. Therefore, the thickness of the peripheral wall of the first hollow tubular segment 26 is approximately 2.67 millimeters.

[0146] The aerosol cooling element 24 comprises 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 entirely from the upstream end 38 of the second hollow tubular segment 34 to the downstream end 40 of the second hollow tubular segment 34. The internal cavity 36 is substantially empty, and therefore substantially unrestricted airflow is possible along the internal cavity 36. The second hollow tubular segment 28, and consequently the aerosol cooling element 24, does not substantially contribute to the overall RTD of the aerosol generating article 10. More specifically, the RTD of the second hollow tubular segment 34 (which is essentially the RTD of the aerosol cooling element 24) is substantially 0 mmH2O.

[0147] The second hollow tubular segment 34 has a length of approximately 8 mm, an outer diameter of approximately 7.25 mm, and an inner diameter of approximately 3.25 mm (D STS) has. Therefore, the thickness of the peripheral wall of the second hollow tubular segment 34 is about 2 millimeters. Therefore, the inner diameter (D) of the first hollow tubular segment 26 is FTS ) and the inner diameter (D) of the second hollow tubular segment 34 STS The ratio between ) is approximately 0.75.

[0148] The aerosol-generating article 10 includes a ventilation zone 60 provided along the second hollow tubular segment 34. More specifically, the ventilation zone is provided about 2 millimeters from the upstream end of the second hollow tubular segment 34. In this embodiment, the ventilation zone 60 includes a circumferential row of perforations through the paper wrapper 70, and the ventilation level of the aerosol-generating article 10 is about 25%.

[0149] In the embodiment shown in Figure 1, the downstream section 14 further comprises a mouthpiece element 42 located downstream of the intermediate hollow section 50. More specifically, the mouthpiece element 42 is positioned immediately downstream of the aerosol cooling element 24. As shown in the drawing of Figure 1, the upstream end of the mouthpiece element 42 abuts against the downstream end 40 of the aerosol cooling element 24.

[0150] The mouthpiece element 42 is provided in the form of a cylindrical plug made of low-density cellulose acetate.

[0151] The mouthpiece element 42 has a length of approximately 12 mm and an outer diameter of approximately 7.25 mm. The RTD of the mouthpiece element 42 is approximately 12 mm of H2O. The ratio of the length of the mouthpiece element 42 to the length of the intermediate hollow section 50 is approximately 0.6.

[0152] The rod 12 of the aerosol-forming substrate has an outer diameter of approximately 7.25 millimeters and a length of approximately 12 millimeters.

[0153] The upstream section 16 comprises an upstream element 46 located immediately upstream of the rod 12 of the aerosol-forming substrate, and the upstream element 46 is longitudinally aligned with the rod 12. In the embodiment shown in Figure 1, the downstream end of the upstream element 46 abuts against the upstream end of the rod 12 of the aerosol-forming substrate. The upstream element 46 is supplied in the form of a cylindrical plug of cellulose acetate. The upstream element 46 has a length of about 5 millimeters. The RTD of the upstream element 46 is about 30 millimeters of H2O.

[0154] The upstream element 46, the rod 12 of the aerosol-forming substrate, the support element 22, the aerosol cooling element 24, and the mouthpiece element 42 are wrapped in a paper wrapper 70.

[0155] The rod 12 of the aerosol-forming substrate comprises an aerosol-forming material and thermally conductive particles 44. The aerosol-forming material comprises a reconstituted and assembled sheet containing tobacco material and glycerin. The thermally conductive particles 44 are carbon particles, specifically expanded graphite particles, having a particle size distribution of D10 particle size of 6.6 micrometers, D50 particle size of 20 micrometers, and D90 particle size of 56 micrometers. Each of the expanded graphite particles has a particle size greater than 2 microns and less than 100 microns. The expanded graphite particles have a volume-average particle size of about 35 microns. Each of the expanded graphite particles is substantially spherical in shape. The expanded graphite particles have a density of less than 1000 kilograms / cubic meter. The aerosol-forming substrate containing the aerosol-forming material and thermally conductive particles 44 has a composite density of approximately 760 kilograms / cubic meter. The expanded graphite particles account for approximately 4.6% by weight of the aerosol-forming substrate. Glycerin accounts for approximately 1.7% by weight of the aerosol-forming substrate.

[0156] The rod 12 of the aerosol-forming substrate is formed by a process that includes the following steps: - A step of premixing guar gum, which is a binder, with glycerin, which is an aerosol-forming agent, to form a first premixture. - A step of forming a second premixture by premixing finely shredded tobacco material with a powder consisting of expanded graphite particles 44 and having a bulk density of approximately 0.065 grams per cubic centimeter. - A step of mixing the first premixture and the second premixture with water to form a slurry. • A process of homogenizing the slurry using a high-shear mixer. • A process of casting slurry onto a conveyor belt. • A step of controlling the thickness of the slurry and drying the slurry to form a sheet with a large aerosol-forming substrate, and • A step of assembling and cutting large sheets of aerosol-forming substrate to form a rod 12 of aerosol-forming substrate.

[0157] After forming the rod 12 of the aerosol-forming substrate, the aerosol-generating article 10 is assembled by positioning the various components of the article 10 and packaging the components inside the wrapper 70.

[0158] Figure 2 shows a schematic cross-sectional view of a first embodiment of the aerosol generating system 100. The system 100 comprises an aerosol generating device 102 and the aerosol generating article 10 shown in Figure 1.

[0159] The aerosol generator 102 comprises a battery 104, a controller 106, a heating blade 108 coupled to the battery, and a smoke extraction detection mechanism (not shown). The controller 106 is coupled to the battery 104, the heating blade 108, and the smoke extraction detection mechanism.

[0160] The aerosol generator 102 further comprises a housing 110 that defines a substantially cylindrical cavity for receiving a portion of the article 10. The heating blade 108 is positioned in the center of the cavity and extends along its long axis from the base of the cavity.

[0161] In this embodiment, the heating blade 108 includes a substrate and an electrically resistive track located on the substrate. The battery 104 is coupled to the heating blade 108 such that it can pass an electric current through the electrically resistive track and heat the electrically resistive track and the heating blade 108 to an operating temperature.

[0162] In use, the user inserts the article 10 into the cavity and passes the heating blade 108 through the upstream element 46 of the aerosol-forming substrate of the article 10 and the rod 12. FIG. 3 shows the article 10 inserted into the cavity of the device 102.

[0163] The user then smokes at the downstream end of the article 10. This causes air to flow through an air inlet (not shown) of the device 102, then through the article 10, from the upstream end 18 to the downstream end 20, and into the user's mouth.

[0164] When the user smokes the article 1 (0), air flows through an air inlet of the device. The smoking detection mechanism detects that the airflow rate through the air inlet has increased above a threshold flow rate that is non-zero. The smoking detection mechanism then sends a signal to the controller 106 in response. The controller 106 then controls the battery (04)to pass an electric current through the electrically resistive track and heat (0)heat the heating blade 108. This heats the rod 12 of the aerosol-forming substrate in contact with the heating blade 108.

[0165] The expanded graphite particles 44 have a significantly higher thermal conductivity than the surrounding aerosol-forming material. Thus, these particles can act as local hot spots and provide a more uniform temperature across the aerosol-forming substrate, particularly radially from the heating blade 108, whereas in prior art substrates there can be significant temperature gradients. This allows a larger proportion of the aerosol-forming substrate to reach a temperature high enough to release volatile compounds, and thus the efficiency of use of the aerosol-forming substrate can be increased.

[0166] Upon heating of the aerosol-forming substrate, it releases volatile compounds. These compounds are carried by the air flowing from the upstream end 18 of article 10 toward the downstream end 20 of article 10. The compounds cool and condense, forming an aerosol as they pass through the internal cavities 28, 36 of the support element and aerosol cooling element. The aerosol then passes through the mouthpiece element 42, thereby removing undesirable particles that could be carried by the airflow into the user's mouth.

[0167] When the user stops inhaling from item 10, the airflow through the device's air intake decreases to below a non-zero threshold flow rate. This is detected by the smoke detection mechanism. The smoke detection mechanism sends a signal to the controller 106 accordingly. The controller 106 then controls the battery 104 to reduce the current passing through the electrical resistance track to zero.

[0168] After smoking item 10 several times, the user may choose to replace item 10 with a new item.

[0169] Figure 3 shows a schematic cross-sectional view of a second embodiment of the aerosol generating system 200. The system 200 comprises an aerosol generating device 202 and the aerosol generating article 11 shown in Figure 1.

[0170] The aerosol generator 202 comprises a battery 204, a controller 206, an inductor coil 208, and a smoke extraction detection mechanism (not shown). The controller 206 is coupled to the battery 204, the inductor coil 208, and the smoke extraction detection mechanism.

[0171] The aerosol generator 202 further comprises a housing 210 that defines a substantially cylindrical cavity for receiving a portion of the article 10. The inductor coil 208 is spirally arranged around the cavity.

[0172] The battery 204 is coupled to the inductor coil 208 so that it can supply alternating current to the inductor coil 208.

[0173] During use, the user inserts the item 11 into the cavity. Figure 3 shows the item 10 inserted into the cavity of the device 202.

[0174] Next, the user inhales smoke at the downstream end of item 10. This causes air to flow through the air intake port (not shown) of the device 202, then through item 10, from the upstream end 18 to the downstream end 20, and into the user's mouth.

[0175] When a user inhales smoke from item 10, air flows through the air intake of the device. The smoke inhalation detection mechanism detects that the airflow rate through the air intake has increased significantly above a non-zero threshold flow rate. The smoke inhalation detection mechanism transmits a signal to the controller 206 accordingly. The controller 206 then controls the battery 204 to pass an 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 substrate is located within this fluctuating electromagnetic field, and the expanded graphite, which is the material of the particles 44, is the susceptor material. Therefore, the fluctuating electromagnetic field induces eddy currents in the particles 44. This heats the particles 44, and thereby heats the nearby aerosol-forming material as well.

[0176] Heating of the aerosol-forming material causes it to release volatile compounds. These compounds are carried by the air flowing from the upstream end 18 of article 10 toward the downstream end 20 of article 10. The compounds cool and condense, forming an aerosol as they pass through the internal cavities 28, 36 of the support element and aerosol cooling element. The aerosol then passes through the mouthpiece element 42, thereby removing undesirable particles that could be carried by the airflow into the user's mouth.

[0177] When the user stops inhaling from item 10, the airflow through the air intake of the device decreases to below a non-zero threshold flow rate. This is detected by the smoke detection mechanism. The smoke detection mechanism sends a signal to the controller 206 accordingly. The controller 206 then controls the battery 204 to reduce the current passing through the electrical resistance track to zero.

[0178] After smoking item 11 several times, the user may choose to replace item 11 with a new item.

[0179] Figure 4 shows a schematic cross-sectional view of a second embodiment of the aerosol-generating article 510. This second embodiment is identical to the first embodiment in Figure 1, except that the rod 12 of the aerosol-forming substrate is replaced by an alternative rod 512 of the aerosol-forming substrate. The same reference numerals are used for the same components in the embodiments of Figures 1 and 3.

[0180] The rod 512 of the aerosol-forming substrate in the second embodiment shown in Figure 4 is identical to the rod 12 of the aerosol-forming substrate in the first embodiment shown in Figure 1, except that the rod 512 of the aerosol-forming substrate in the third embodiment shown in Figure 4 additionally includes an elongated susceptor element 580.

[0181] The susceptor element 580 is positioned substantially along the longitudinal axis within the aerosol-forming substrate rod 512, so as to be approximately parallel to the longitudinal axis of the aerosol-forming substrate rod 512. As shown in Figure 4, the susceptor element 580 is positioned at the radial center within the rod and extends along the longitudinal axis of the rod 12.

[0182] The susceptor element 580 extends along the entire length of the rod 512 of the aerosol-forming substrate, from the upstream end to the downstream end. Therefore, the susceptor element 580 has substantially the same length as the rod 512 of the aerosol-forming substrate.

[0183] 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 millimeters, a thickness of about 60 micrometers, and a width of about 4 millimeters.

[0184] The aerosol generating article 510 of FIG. 4 may be used with the aerosol generating device 202 of FIG. 3 in the same manner as the aerosol generating article 10 of FIG. 1. In particular, including the susceptor element 580 means that the article 510 can be inductively heated. In the example shown in FIG. 4, both the expanded graphite particles and the susceptor element 580 are inductively heatable. Therefore, both the susceptor element 580 and the expanded graphite particles 44 contribute to the heating during use.

[0185] The rods of the aerosol forming substrates 12, 512 of the aerosol generating articles 10, 510 contain 4.6 wt% expanded graphite particles and can be said to be thermally strengthened. The inventors have found that such aerosol generating articles according to the present disclosure have improved yields and delivery efficiencies of nicotine and glycerin compared to aerosol generating articles including rods of aerosol forming substrates that do not contain expanded graphite particles.

[0186] The inventors measured the yields of nicotine and glycerin from an aerosol generating article 602 that does not contain thermally conductive particles, an aerosol generating article 604 in which 4.6% of the tobacco of the aerosol generating article 602 is replaced with graphite particles, and an aerosol generating article 606 in which 4.6% of the tobacco of the aerosol generating article 602 is replaced with expanded graphite particles. In other words, the aerosol generating article 606 is an aerosol generating article according to the present disclosure and can be the aerosol generating article shown in FIG. 1.

[0187] FIGS. 5-7 show the results when the aerosol generating articles 602-606 are used with a resistive aerosol generating device (such as the device shown in FIG. 2).

[0188] Figure 5 is a bar graph 600 showing the nicotine yield for each aerosol-generating article on the Y axis. The yield is measured in micrograms per article and is the total yield achieved during a usage session. The X axis has bars for each of the aerosol-generating articles 602 to 606. The nicotine yield from aerosol-generating article 602, which does not contain thermally conductive particles, is 1150 micrograms per article. The nicotine yield from aerosol-generating article 604, which contains 4.6 wt% graphite particles, is 1190 micrograms per article. The nicotine yield from aerosol-generating article 606, which contains 4.6 wt% expanded graphite particles, is 1125 micrograms per article.

[0189] Figure 6 is a bar graph 700 showing the glycerin yield for each aerosol-generating article on the Y axis. The yield is measured in micrograms per article and is the total yield achieved during the usage session. The X axis has bars for each of the aerosol-generating articles 602 to 606. The glycerin yield from aerosol-generating article 602, which does not contain thermally conductive particles, is 3640 micrograms per article. The glycerin yield from aerosol-generating article 604, which contains 4.6 wt% graphite particles, is 4150 micrograms per article. The glycerin yield from aerosol-generating article 606, which contains 4.6 wt% expanded graphite particles, is 4540 micrograms per article.

[0190] Figure 7 is a bar graph 800 showing the delivery efficiency of nicotine and glycerin for each aerosol-generating article 602-608 during a usage session. Efficiency is shown on the Y-axis as a percentage. Specifically, efficiency is the proportion of the total initial nicotine or glycerin contained in the aerosol-generating article that is delivered to the user or smoking machine throughout the usage session of that article. Bar 802, which shows nicotine delivery efficiency, is hatched diagonally. Bar 804, which shows glycerin delivery efficiency, is hatched with a vertical dashed line.

[0191] The nicotine delivery efficiency from aerosol-generating article 602, which does not contain thermally conductive particles, is 29%. The nicotine delivery efficiency from aerosol-generating article 604, which contains 4.6% by weight of graphite particles, is 31.5%. The nicotine delivery efficiency from aerosol-generating article 606, which contains 4.6% by weight of expanded graphite particles, is 35.4%.

[0192] The glycerin delivery efficiency from aerosol-generating article 602, which does not contain thermally conductive particles, is 9.3%. The glycerin delivery efficiency from aerosol-generating article 604, which contains 4.6% by weight of graphite particles, is 10.6%. The nicotine delivery efficiency from aerosol-generating article 606, which contains 4.6% by weight of expanded graphite particles, is 12.1%.

[0193] Figures 8-10 show the results when aerosol generating articles 602-606 are used together with an induction aerosol generating device (such as the device shown in Figure 3).

[0194] Figure 8 is a bar graph showing the nicotine yield for each aerosol-generating article on the Y axis. The yield is measured in micrograms per article and represents the total yield achieved during a usage session. The X axis has bars for each of the aerosol-generating articles 602-606. The nicotine yield from aerosol-generating article 602, which does not contain thermally conductive particles, is 790 micrograms per article. The nicotine yield from aerosol-generating article 604, which contains 4.6 wt% graphite particles, is 886 micrograms per article. The nicotine yield from aerosol-generating article 606, which contains 4.6 wt% expanded graphite particles, is 1197 micrograms per article.

[0195] Figure 9 is a bar graph with 1000 bars on the Y axis showing the glycerin yield for each aerosol-generating article. The yield is measured in micrograms per article and is the total yield achieved during the usage session. The X axis has bars for each of the aerosol-generating articles 602 to 606. The glycerin yield from aerosol-generating article 602, which does not contain thermally conductive particles, is 3100 micrograms per article. The glycerin yield from aerosol-generating article 604, which contains 4.6 wt% graphite particles, is 3840 micrograms per article. The glycerin yield from aerosol-generating article 606, which contains 4.6 wt% expanded graphite particles, is 4800 micrograms per article.

[0196] Figure 10 is a bar graph 1100 showing the delivery efficiency of nicotine and glycerin for each aerosol-generating article 602-608 during a usage session. Efficiency is shown on the Y-axis as a percentage. Specifically, efficiency is the proportion of the total initial nicotine or glycerin contained in the aerosol-generating article that is delivered to the user or smoking machine throughout the usage session of that article. Bar 1102, which shows nicotine delivery efficiency, is hatched diagonally. Bar 1104, which shows glycerin delivery efficiency, is hatched with vertical dashed lines.

[0197] The nicotine delivery efficiency from aerosol-generating article 602, which does not contain thermally conductive particles, is 19.1%. The nicotine delivery efficiency from aerosol-generating article 604, which contains 4.6% by weight of graphite particles, is 23.8%. The nicotine delivery efficiency from aerosol-generating article 606, which contains 4.6% by weight of expanded graphite particles, is 31.4%.

[0198] The glycerin delivery efficiency from aerosol-generating article 602, which does not contain thermally conductive particles, is 7.6%. The glycerin delivery efficiency from aerosol-generating article 604, which contains 4.6% by weight of graphite particles, is 9.9%. The nicotine delivery efficiency from aerosol-generating article 606, which contains 4.6% by weight of expanded graphite particles, is 12.1%.

[0199] Therefore, the bar graphs in Figures 5, 6, 8, and 9 show that the yields of both nicotine and glycerin increase when the aerosol-forming substrate is thermally strengthened by replacing a small amount of tobacco with expanded graphite, and that the increase in yield is greater when expanded graphite particles are used instead of graphite particles to thermally strengthen the substrate. The increase in aerosols is achieved regardless of whether aerosols are generated as a result of resistance heating or induction heating of the substrate.

[0200] Similarly, the bar graph in Figure 7 shows that the delivery efficiency of both nicotine and glycerin is improved when the aerosol-forming substrate is thermally strengthened by replacing a small amount of tobacco with expanded graphite, and that the improvement in efficiency is greater when expanded graphite particles are used instead of graphite particles to thermally strengthen the substrate. The increase in aerosols is achieved regardless of whether aerosols are generated as a result of resistance heating or induction heating of the substrate.

[0201] An aerosol-forming substrate containing expanded graphite particles according to a particular embodiment is described above. Naturally, the aerosol-forming substrate may differ in other embodiments. For example, the aerosol-forming substrate may contain expanded graphite particles in different amounts, ratios, sizes, or densities than those in the particular embodiment described above. In any case, the presence of expanded graphite particles may thermally enhance the substrate. Furthermore, other characteristics of the substrate, such as other features of the chemical composition of the substrate, may differ.

[0202] Figure 11 shows an alternative embodiment of the aerosol generating article 1110, which includes a heat-enhanced aerosol-forming substrate 1112 containing individual elements of a first material 1113 and individual elements of a second material 1114. Each individual element of the second material 1114 may be in contact with many individual elements of the first material 1113 and thus can act as a heat path through the substrate. The ratio of the first and second materials may vary depending on the specific properties of the first and second materials and the desired properties of the aerosol-forming substrate 1112. Apart from the difference in the substrate itself, the aerosol generating article 1110 is identical to the aerosol generating article 10 in Figure 1, with similar features numbered accordingly.

[0203] Several specific heat-enhanced aerosol-forming substrates are identified as examples. The examples use combinations of three specific materials, namely material A, material B, and material C, as specified below.

[0204] Material A Material A is a standard homogenized tobacco material. Material A contains tobacco powder, about 4% by weight of cellulose fibers, about 3% by weight of guar as a binder, and about 15% by weight of glycerin as an aerosol former.

[0205] Material A is formed by a process that includes the following steps: - A step of premixing guar gum, which is a binder, with glycerin, which is an aerosol-forming agent, to form a first premixture. • A step of pre-mixing tobacco powder and water to form a second premixture, • A step of mixing the first and second premixtures to form a slurry. • A process of homogenizing the slurry using a high-shear mixer. • A process of casting slurry onto a conveyor belt. The process involves controlling the thickness of the slurry, drying the slurry to form a large sheet of reconstructed, substantially homogeneous, tobacco-containing aerosol-forming material, and - A process of crimping and shredding a large sheet of reconfigured and substantially homogeneous aerosol-forming material to form cut fillers.

[0206] Material A has a thermal conductivity of 0.12 W / mK.

[0207] Material B Material B is a homogenized tobacco material with increased thermal conductivity. Material B contains tobacco powder, approximately 5% by weight of expanded graphite particles, approximately 4% by weight of cellulose fibers, approximately 3% by weight of guar as a binder, and approximately 15% by weight of glycerin as an aerosol former.

[0208] The expanded graphite particles have a particle size distribution with D10 particle size of 6.6 microns, D50 particle size of 20 microns, and D90 particle size of 56 microns. Each expanded graphite particle has a particle size greater than 2 microns and less than 100 microns. The expanded graphite particles have a volume-average particle size of approximately 35 microns. Each expanded graphite particle is substantially spherical in shape. The expanded graphite particles have a density of less than 1000 kilograms / cubic meter.

[0209] Material B is formed by a process that includes the following steps: - A step of premixing guar gum, which is a binder, with glycerin, which is an aerosol-forming agent, to form a first premixture. - A step of premixing tobacco powder, expanded graphite particles, and water to form a second premixture. • A step of mixing the first and second premixtures to form a slurry. • A process of homogenizing the slurry using a high-shear mixer. • A process of casting slurry onto a conveyor belt. The process involves controlling the thickness of the slurry, drying the slurry to form a large sheet of reconstructed, substantially homogeneous, tobacco-containing aerosol-forming material, and - A process of crimping and shredding a large sheet of reconfigured and substantially homogeneous aerosol-forming material to form cut fillers.

[0210] Material B has a thermal conductivity at least 10% higher than that of material A, for example, 0.14 W / mK to 0.25 W / mK. Replacing 5 wt% tobacco powder with expanded graphite particles slightly reduces the overall tobacco content, and therefore the nicotine content. However, the thermal conductivity of the material increases. In experiments, adding 4.5 wt% to 10 wt% expanded graphite particles to homogenized tobacco material increased the thermal conductivity by 20% to 50%.

[0211] Material C Material C is a non-tobacco aerosol-forming material with high thermal conductivity. Material C contains approximately 76.1% by weight of expanded graphite particles on a dry weight basis.

[0212] Material C further comprises approximately 17.7% by weight of an aerosol-forming agent. In this embodiment, the aerosol-forming agent is glycerol, in particular ICOF European food-grade (>99.5% purity) glycerol.

[0213] Material C further contains approximately 3.9% by weight of fibers on a dry weight basis. In this embodiment, the fibers are cellulose fibers, and in particular birch cellulose fibers of Stora Enso OYJ.

[0214] Material C further comprises about 2.3% by weight of a binder on a dry weight basis. In this embodiment, the binder is guar gum, in particular guar gum from Gumix International Inc.

[0215] Material C may further contain one or more of the following: nicotine, an acid such as fumaric acid, a plant component such as clove or rosmarinus, water, and a flavoring agent.

[0216] Material C is formed by the process described below.

[0217] The slurry is formed using a laboid sparer having the ability to mix viscous liquids, disperse powders through liquids, and remove gases from the mixture (e.g., by applying a vacuum or other appropriately low pressure). In this embodiment, a laboid sparer commercially available from PC Laborsystem was used.

[0218] To form the slurry, the first mixture is formed by adding approximately 7.11 grams of aerosol former, then approximately 157.5 grams of water, then approximately 1.57 grams of fiber to a Labodysseur. These first components are then mixed at 600-700 rpm for 5 minutes at 25 degrees Celsius to ensure a homogeneous mixture and hydrate the fiber. The second mixture is then formed by manually mixing approximately 32.95 grams of thermal conductive particles and approximately 0.92 grams of binder. This mixing of the second mixture prevents the formation of lumps in the Lab dispersion. The second mixture is then added to the first mixture to form a combined mixture. The combined mixture is then mixed at 5000 rpm for 4 minutes at 25 degrees Celsius and a first reduced pressure of approximately 200 mbar. Reduced pressure can help ensure that the thermal conductive particles are homogeneously dispersed in the mixture, and that there is little trapped air and very few lumps in the combined mixture. Next, the combined mixture is mixed at 5000 rpm for 20 seconds under a second reduced pressure of 25 degrees Celsius and approximately 100 mbar. This second reduced pressure may help remove any remaining air bubbles. This forms a slurry for casting.

[0219] The slurry is then cast and dried using appropriate equipment. In this embodiment, a commercially available Labcoater Mathis apparatus is used. This apparatus includes stainless steel, a flat support, and a comb blade for adjusting the thickness of the slurry cast on the flat support.

[0220] The slurry is cast onto a flat support, and the gap between the spool blade and the flat support is set to 0.6 millimeters. This ensures that the slurry thickness at any given point is 0.6 millimeters or less.

[0221] The slurry is then dried in high-temperature air at 120-140 degrees Celsius for 2-5 minutes. After this drying, a sheet of aerosol-forming substrate is formed. This sheet has a thickness of approximately 159 microns, a basis weight of approximately 125.7 grams / square meter, and a density of approximately 0.79 kilograms / cubic meter.

[0222] Next, the sheet is crimped and cut to form material C. The thermal conductivity of material C is at least 0.28 W (mK).

[0223] It can be seen that by combining materials A, B, and C in different ratios, a wide range of different aerosol-forming substrates can be generated.

[0224] Therefore, the first exemplary aerosol-forming substrate 12 may comprise a mixture of 60% by weight of individual elements of material A and 40% by weight of individual elements of material B. Both material A and material B are homogenized tobacco materials, but material B has increased thermal conductivity due to the presence of expanded graphite particles. The presence of material B in the first exemplary aerosol-forming substrate provides individual elements with increased thermal conductivity, resulting in improved aerosol and nicotine delivery.

[0225] The second exemplary aerosol-forming substrate 12 may contain a mixture of 70 wt% of individual elements of material A and 30 wt% of individual elements of material C. The presence of material C in the second exemplary aerosol-forming substrate reduced the overall amount of tobacco in the substrate but significantly improved the thermal conductivity. Material C also contributes to aerosol generation.

[0226] A third exemplary aerosol-forming substrate 12 may comprise a mixture of 80% by weight of individual elements of material B and 20% by weight of individual elements of material C. In this embodiment, the first material is material B, which is a homogenized tobacco material with increased thermal conductivity, and the second material is material C.

[0227] Any of these three exemplary aerosol-forming substrates can be used as the substrate for the aerosol-generating article 10 in Figure 1 or the aerosol-generating article 1110 in Figure 11.

[0228] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers representing amounts, quantities, percentages, etc., should be understood in all cases as being modified by the term “approximately.” Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges therewith, which may or may not be specifically listed herein. Thus, in this context, the number A is understood as A ± 10%. In this context, the number A may be considered to include a number that falls within the general standard error of the measurement of the characteristic that the number A modifies. In some cases as used in the appended claims, the number A may deviate by the percentage listed above, provided that the amount of deviation does not substantially affect the basic and novel characteristics(s) of the claimed invention. Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges therewith, which may or may not be specifically listed herein.

Claims

1. An aerosol-forming substrate for use in an aerosol-generating article, comprising expanded graphite particles.

2. The aerosol-forming substrate according to claim 1, wherein the aerosol-forming substrate has a thermal conductivity of at least 0.12 W / (mK).

3. The aerosol generating article according to claim 1, wherein the expanded graphite particles constitute at least 1% by weight of the aerosol forming substrate.

4. Based on dry weight, 1 to 90% by weight of expanded graphite particles, 7-60% by weight of an aerosol-forming material, 2-20% by weight of fiber, The aerosol-forming substrate according to claim 1, comprising 2 to 10% by weight of a binder.

5. The aerosol-forming substrate according to claim 1, comprising 1 to 15% by weight of expanded graphite particles.

6. The aerosol-forming substrate according to claim 1, wherein the expanded graphite particles have a particle size distribution having a volume D10 particle size of 1 to 20 microns.

7. The aerosol-forming substrate according to claim 1, wherein the expanded graphite particles have a particle size distribution having a volume D90 particle size of 50 to 300 microns.

8. The aerosol-forming substrate according to claim 1, wherein the expanded graphite particles are substantially homogeneously distributed throughout the entire aerosol-forming substrate.

9. The aerosol-forming substrate according to claim 1, wherein the aerosol-forming substrate is a tobacco-free aerosol-forming substrate.

10. The aerosol generating substrate according to claim 1, comprising tobacco particles.

11. A method for forming an aerosol-forming substrate according to claim 1, Forming a slurry containing expanded graphite particles, aerosol formers, fibers, and a binder, A method comprising casting and drying the slurry to form the aerosol-forming substrate or a precursor of the aerosol-forming substrate.

12. Forming the slurry The aerosol forming body and, The aforementioned fiber, Water and, Selectively, acid and, To optionally form a first mixture containing nicotine, The expanded graphite particles, To form a second mixture containing the aforementioned binder, The method according to claim 11, comprising adding the second mixture to the first mixture to form a combined mixture.

13. An aerosol generating article comprising an aerosol-forming substrate according to claim 1, or an aerosol-forming substrate formed by the method described in claim 11.

14. The aerosol generating article according to claim 13, comprising a plurality of elements including the aerosol-forming substrate assembled within a wrapper.

15. An aerosol generating system comprising an aerosol generating article according to claim 13, and an electric aerosol generating device for heating the aerosol forming substrate.

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