An aerosol-forming substrate in the form of a solid unitary body forming two particulate materials.

Abstract

An aerosol-forming substrate (1020) for use in an aerosol-generating system is provided. The aerosol-forming substrate is a solid unitary body and comprises a first particulate material and a second particulate material. The first particulate material is formed from particles having a D50 particle size of between 2 micrometers and 20 micrometers. The second particulate material is formed from particles having a D50 particle size of between 50 micrometers and 80 micrometers. An aerosol-generating article is also provided that comprises the aerosol-forming substrate.

Description

[Technical field]

[0001] The present invention relates to an aerosol-forming substrate. In particular, the present invention relates to an aerosol-forming substrate for use in an aerosol generation system, the aerosol-forming substrate comprising a first particulate material and a second particulate material, and a method for producing such an aerosol-forming substrate. [Background technology]

[0002] Aerosol generating systems for delivering aerosols to a user typically comprise an atomizer configured to generate an inhalable aerosol from an aerosol-forming substrate. Some known aerosol generating systems comprise a thermal atomizer, such as an electric heater or an induction heating device. The thermal atomizer is configured to heat and vaporize the aerosol-forming substrate to generate an aerosol. A typical aerosol-forming substrate for use in an aerosol generating system is a nicotine formulation, which may be a liquid nicotine formulation that includes an aerosol former such as glycerin and propylene glycol. Alternatively, an aerosol-forming substrate for use in an aerosol generating system may comprise a solid component. For example, the aerosol-forming substrate may include a particulate material having a certain particle size.

[0003] However, it has been found that solid aerosol-forming substrates containing particulate material can be difficult to handle during manufacturing due to the agglomeration of the particulate material.Furthermore, aerosol-forming substrates containing solid particles formed into sheets can exhibit defects such as stretch marks and slits.It has also been found that such aerosol-forming substrates may not provide aerosol delivery throughout the entire time of the user's experience of the aerosol-forming substrate.

[0004] It would be desirable to provide an aerosol-forming substrate that is easy to handle during manufacturing and does not exhibit the deficiencies observed in the prior art, and that provides acceptable delivery of the aerosol throughout the duration of a user's experience with the aerosol-forming substrate. Summary of the Invention

[0005] The present disclosure relates to an aerosol-forming substrate for use in an aerosol generating system. The aerosol-forming substrate may be a solid unitary body. The aerosol-forming substrate may comprise a first particulate material. The aerosol-forming substrate may comprise a second particulate material. The first particulate material may be formed from particles having a D50 particle size of between 2 micrometers and 20 micrometers. The second particulate material may be formed from particles having a D50 particle size of between 50 micrometers and 80 micrometers.

[0006] According to the present invention there is provided an aerosol-forming substrate for use in an aerosol generating system, the substrate comprising a first particulate material and a second particulate material, the first particulate material being formed from particles having a D50 particle size of between 2 micrometers and 20 micrometers and the second particulate material being formed from particles having a D50 particle size of between 50 micrometers and 80 micrometers.

[0007] According to the present invention there is provided an aerosol-forming substrate for use in an aerosol generating system, the aerosol-forming substrate being a solid unitary body comprising a first particulate material and a second particulate material, the first particulate material being formed from particles having a D50 particle size of between 2 micrometers and 20 micrometers and the second particulate material being formed from particles having a D50 particle size of between 50 micrometers and 80 micrometers.

[0008] As used herein in connection with the present invention, the term "solid unitary body" refers to an aerosol-forming substrate comprising a first particulate material and a second particulate material held together in a single solid agglomerate.

[0009] According to the present invention there is also provided a method for manufacturing an aerosol-forming substrate, the method comprising providing a first particulate material formed from particles having a D50 particle size of between 2 micrometers and 20 micrometers, providing a second particulate material formed from particles having a D50 particle size of between 50 micrometers and 80 micrometers, mixing the first particulate material and the second particles in an aqueous solution to form a slurry, casting the slurry, and drying the cast slurry to form a solid substrate.

[0010] The inventors of the present invention have identified that aerosol-forming substrates comprising particles having a D50 particle size between 2 micrometers and 20 micrometers, or "small" particles, may exhibit disadvantageous agglomeration during manufacture and processing. Furthermore, if the aerosol-forming substrate is formed as a thin sheet, the sheet may exhibit defects including stretch marks and slits. However, aerosol-forming substrates comprising particles having a D50 particle size between 2 micrometers and 20 micrometers result in high density aerosol-forming substrates. This may advantageously provide enhanced aerosol generation throughout the duration of the user's experience of the aerosol-forming substrate.

[0011] On the other hand, the inventors of the present invention have identified that aerosol-forming substrates comprising particles having a D50 particle size of 50 micrometers to 80 micrometers, or "large" particles, may advantageously be easier to handle during manufacture and processing since the particles do not exhibit agglomeration to the same extent. Furthermore, if the aerosol-forming substrate is formed as a sheet, the sheet may be less likely to exhibit defects, allowing the particles to be more easily formed into thin sheets. However, aerosol-forming substrates comprising particles having a D50 particle size of 50 micrometers to 80 micrometers result in low density aerosol-forming substrates that exhibit reduced or diminished aerosol delivery over the life of the aerosol-forming substrate.

[0012] By providing an aerosol-forming substrate comprising a first particulate material comprising particles having a D50 size between 2 micrometers and 20 micrometers, and a second particulate material comprising particles having a D50 size between 50 micrometers and 80 micrometers, the inventors have found that the advantageous properties of both particle sizes can be realised, whilst at the same time the disadvantageous properties of each particle size can be mitigated.

[0013] In other words, the inventors have found that providing an aerosol-forming substrate comprising a first particulate material formed from particles having a D50 particle size of between 2 micrometers and 20 micrometers and a second particulate material formed from particles having a D50 particle size of between 50 micrometers and 80 micrometers may advantageously be easy to handle during manufacture and processing and may exhibit good aerosol generation throughout the time of a user's experience of the aerosol-forming substrate.

[0014] As used herein in connection with the present invention, the term "D50 particle size" refers to the median particle size of a particulate material. The D50 particle size is the particle size that splits the distribution in half, with half of the particles being larger than the D50 particle size and half of the particles being smaller than the D50 particle size. The particle size distribution may be determined by laser diffraction. For example, the particle size distribution may be determined by laser diffraction using a Malvern Mastersizer 3000 laser diffraction particle size analyzer according to the manufacturer's instructions.

[0015] In use, the aerosol-forming substrate may form part of an aerosol-generating article that may be inserted into an aerosol-generating device. The aerosol-generating device may include a heater that heats the aerosol-forming substrate to emit an aerosol that may be delivered to a user. The aerosol-forming substrate may emit an aerosol when heated to at least about 100 degrees Celsius, at least about 200 degrees Celsius, at least about 250 degrees Celsius, at least about 350 degrees Celsius, or at least about 500 degrees Celsius. For example, the aerosol-forming substrate may emit an aerosol when heated to between about 100 degrees Celsius and about 850 degrees Celsius, between about 200 degrees Celsius and about 600 degrees Celsius, or between about 250 degrees Celsius and about 400 degrees Celsius. For example, the aerosol-forming substrate may emit an aerosol when heated to about 260 degrees Celsius.

[0016] As used herein in connection with the present invention, the term "aerosol-forming substrate" refers to a substrate capable of generating, upon heating, a volatile compound capable of forming an aerosol. The aerosol generated from the aerosol-forming substrate may be visible or invisible to the human eye and may include vapor (e.g., gaseous fine particles of a substance that is normally liquid or solid at room temperature), as well as gas and liquid droplets of condensed vapor.

[0017] The second particulate material may be formed from particles having a D50 particle size at least 10 micrometers larger than the D50 particle size of the first particulate material. For example, the second particulate material may be formed from particles having a D50 particle size at least 10 micrometers larger, 15 micrometers larger, 20 micrometers larger, 30 micrometers larger, 40 micrometers larger, or 50 micrometers larger than the D50 particle size of the first particulate material.

[0018] The second particulate material may be formed from particles having a D50 particle size that is 100 micrometers or less larger than the D50 particle size of the first particulate material. For example, the second particulate material may be formed from particles having a D50 particle size that is 90 micrometers or less larger, 80 micrometers or less larger, 70 micrometers or less larger, 60 micrometers or less larger, 55 micrometers or less larger, or 50 micrometers or less larger than the D50 particle size of the first particulate material.

[0019] The first particulate material and the second particulate material may be bound together using a binder to form the aerosol-forming substrate.

[0020] The first particulate material and the second particulate material may be bound together using pressure to form the aerosol-forming substrate.

[0021] The first particulate material and the second particulate material may be bonded together using a pressing, extrusion process, or a casting process.

[0022] The aerosol-forming substrate may have a large surface area.

[0023] The aerosol-forming substrate may be a sheet, strip, rod, or pellet.

[0024] The aerosol-forming substrate may be manufactured by any method. The aerosol-forming substrate may be manufactured using a pressing process. The aerosol-forming substrate may be manufactured using an extrusion process. The aerosol-forming substrate may be manufactured using a casting process. The method may include forming a slurry of a first particulate material and a second particulate material in an aqueous solution. The aqueous solution may further include a binder. The slurry may then be cast, for example, using a continuous casting process. The cast slurry may then be dried to form a solid unitary body comprising the first particulate material and the second particulate material. The cast slurry may be dried through the use of a suitable mold to form a solid unitary body having any desired geometric shape. In some examples, the cast slurry may be dried to form a sheet. The sheet may be crimped and folded to form a completed aerosol-forming substrate. In some examples, the sheet may be over-crimped to cut the sheet into a plurality of strips. In other examples, the cast slurry may be dried to form strips, rods, or pellets.

[0025] The aerosol-forming substrate may comprise any proportion of the first particulate material and the second particulate material. The ratio of the mass of the first particulate material to the mass of the second particulate material in the aerosol-forming substrate may be greater than 1. In other words, on a mass basis, the aerosol-forming substrate may comprise more of the first particulate material than the second particulate material.

[0026] The ratio of the mass of the first particulate material to the mass of the second particulate material in the aerosol-forming substrate may be less than or equal to 1. In other words, on a mass basis, the aerosol-forming substrate may comprise more of the second particulate material than the first particulate material.

[0027] The ratio of the mass of the first particulate material to the mass of the second particulate material in the aerosol-forming substrate may be no more than 5: 1. For example, the ratio of the mass of the first particulate material to the mass of the second particulate material in the aerosol-forming substrate may be no more than 3: 1, no more than 1.

[0028] The ratio of the mass of the first particulate material to the mass of the second particulate material in the aerosol-forming substrate may be no more than 1:2, in other words, there is at least twice as much of the second particulate material as the first particulate material by mass.

[0029] The inventors have found that if more than one-third of the mass of the particulate material in the aerosol-forming substrate comprises a first particulate material formed from particles having a D50 particle size between 2 micrometers and 20 micrometers, the aerosol-forming substrate may exhibit defects such as cracks or slits.

[0030] The ratio of the mass of the first particulate material to the mass of the second particulate material in the aerosol-forming substrate may be at least 1: 10. For example, the ratio of the mass of the first particulate material to the mass of the second particulate material in the aerosol-forming substrate may be at least 1:8, at least 1:5, or at least 1:3.

[0031] The ratio of the mass of the first particulate material to the mass of the second particulate material in the aerosol-forming substrate may be from 1:10 to 5:1, from 1:8 to 3:1, from 1:5 to 1, from 1:5 to 1:2, from 1:3 to 1:2. The ratio of the mass of the first particulate material to the mass of the second particulate material in the aerosol-forming substrate may be about 1:2.

[0032] The aerosol-forming substrate may have a first particulate material content of greater than 1 weight percent.

[0033] As used herein with reference to the present invention, all weight percentages are given on a dry weight basis.

[0034] The aerosol-forming substrate may have a first particulate material content of greater than 5 weight percent, greater than 8 weight percent, greater than 10 weight percent, or greater than 13 weight percent.

[0035] The aerosol-forming substrate may have a first particulate material content of 30 weight percent or less. For example, the aerosol-forming substrate may have a first particulate material content of 25 weight percent or less, 20 weight percent or less, or 17 weight percent or less.

[0036] The aerosol-forming substrate may have a first particulate material content of 5 weight percent to 30 weight percent. For example, the aerosol-forming substrate may have a first particulate material content of 5 weight percent to 25 weight percent, 5 weight percent to 20 weight percent, or 5 weight percent to 17 weight percent.

[0037] The aerosol-forming substrate may have a first particulate material content of between 8 percent and 30 percent by weight. For example, the aerosol-forming substrate may have a first particulate material content of between 10 percent and 30 percent by weight, or between 13 percent and 30 percent by weight.

[0038] The aerosol-forming substrate may have a first particulate material content of between 8 percent and 25 percent by weight. For example, the aerosol-forming substrate may have a first particulate material content of between 10 percent and 20 percent by weight, or between 13 percent and 17 percent by weight.

[0039] The aerosol-forming substrate may have a first particulate material content of about 15 percent by weight.

[0040] The aerosol-forming substrate may have 2 percent by weight or more of the second particulate material.

[0041] The aerosol-forming substrate may have a second particulate material content of greater than 10 weight percent, greater than 16 weight percent, greater than 20 weight percent, or greater than 26 weight percent.

[0042] The aerosol-forming substrate may have a second particulate material content of 60 weight percent or less. For example, the aerosol-forming substrate may have a second particulate material content of 50 weight percent or less, 40 weight percent or less, or 34 weight percent or less.

[0043] The aerosol-forming substrate may have a second particulate material content of 10 weight percent to 60 weight percent. For example, the aerosol-forming substrate may have a second particulate material content of 10 weight percent to 50 weight percent, 10 weight percent to 40 weight percent, or 10 weight percent to 34 weight percent.

[0044] The aerosol-forming substrate may have a second particulate material content of between 16 percent and 60 percent by weight. For example, the aerosol-forming substrate may have a second particulate material content of between 20 percent and 60 percent by weight, or between 26 percent and 60 percent by weight.

[0045] The aerosol-forming substrate may have a second particulate material content of between 20 percent and 40 percent by weight. For example, the aerosol-forming substrate may have a first particulate material content of between 26 percent and 34 percent by weight.

[0046] The aerosol-forming substrate may have a second particulate material content of about 30 percent by weight.

[0047] The aerosol-forming substrate may further comprise one or more aerosol formers.

[0048] Providing one or more aerosol formers advantageously aids the aerosol-forming substrate in generating an aerosol when the aerosol-forming substrate is heated.

[0049] The one or more aerosol formers may include glycerin. The one or more aerosol formers may include propylene glycol. The one or more aerosol formers may include a combination of glycerin and propylene glycol.

[0050] The aerosol-forming substrate may have an aerosol former content of greater than 0.5 percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than 10 percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than 20 percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than 30 percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than 40 percent by weight.

[0051] The aerosol-forming substrate may have an aerosol former content of 80 percent by weight or less. The aerosol-forming substrate may have an aerosol former content of 70 percent by weight or less. The aerosol-forming substrate may have an aerosol former content of 60 percent by weight or less. The aerosol-forming substrate may have an aerosol former content of 50 percent by weight or less. The aerosol-forming substrate may have an aerosol former content of 42 percent by weight or less.

[0052] In some instances, aerosol-forming substrates having an aerosol former content greater than about 42 weight percent have proven difficult to manufacture.

[0053] The first particulate material may be formed from particles having a D50 particle size of 2 micrometers to 20 micrometers, 5 micrometers to 20 micrometers, 10 micrometers to 20 micrometers, or 15 micrometers to 20 micrometers.

[0054] The first particulate material may be formed from particles having a D50 particle size of between 2 micrometers and 15 micrometers, between 2 micrometers and 10 micrometers, or between 2 micrometers and 5 micrometers.

[0055] The first particulate material may be formed from particles having a D50 particle size of between 5 micrometers and 15 micrometers.The first particulate material may be formed from particles having a D50 particle size of about 10 micrometers.

[0056] The second particulate material may be formed from particles having a D50 particle size of 50 micrometers to 80 micrometers, 60 micrometers to 80 micrometers, 70 micrometers to 80 micrometers, or 75 micrometers to 80 micrometers.

[0057] The second particulate material may be formed from particles having a D50 particle size of 50 micrometers to 75 micrometers, 50 micrometers to 70 micrometers, or 50 micrometers to 60 micrometers.

[0058] The second particulate material may be formed from particles having a D50 particle size of between 55 micrometers and 65 micrometers. The second particulate material may be formed from particles having a D50 particle size of about 59 micrometers.

[0059] The first particulate material may be formed from particles having a D50 particle size of 10 micrometers and the second particulate material may be formed from particles having a D50 particle size of 59 micrometers.

[0060] It has been found that providing an aerosol-forming substrate comprising a first particulate material and a second particulate material having these D50 particle sizes can advantageously exhibit both improved handling during manufacture, as well as better delivery of the aerosol during use.

[0061] The first particulate material may be formed from particles having a D95 particle size of at least 10 micrometers.

[0062] As used herein in connection with the present invention, the term "D95 particle size" is the particle size below which the mass fraction of particles has a particle size of 95 percent.

[0063] The first particulate material may be formed from particles having a D95 particle size of at least 15 micrometers, at least 20 micrometers, or at least 30 micrometers.

[0064] The first particulate material may be formed from particles having a D95 particle size of 60 micrometers or less, 50 micrometers or less, or 40 micrometers or less.

[0065] The first particulate material may be formed from particles having a D95 of 10 micrometers to 60 micrometers, 15 micrometers to 50 micrometers, 20 micrometers to 40 micrometers, or 30 micrometers to 40 micrometers.

[0066] The second particulate material may be formed from particles having a D95 particle size of at least 80 micrometers.

[0067] The second particulate material may be formed from particles having a D95 particle size of at least 90 micrometers, at least 100 micrometers, or at least 110 micrometers.

[0068] The second particulate material may be formed from particles having a D95 particle size of 130 micrometers or less, 125 micrometers or less, or 120 micrometers or less.

[0069] The second particulate material may be formed from particles having a D95 of 80 micrometers to 130 micrometers, 90 micrometers to 125 micrometers, 100 micrometers to 120 micrometers, or 110 micrometers to 120 micrometers.

[0070] The first particulate material may be formed from particles having a D95 particle size of 33 micrometers.The second particulate material may be formed from particles having a D95 particle size of 116 micrometers.

[0071] The second particulate material may be formed from particles having a D95 particle size at least 40 micrometers larger than the D95 particle size of the first particulate material. For example, the second particulate material may be formed from particles having a D95 particle size at least 50 micrometers larger, 60 micrometers larger, 70 micrometers larger, or 80 micrometers larger than the D95 particle size of the first particulate material.

[0072] The second particulate material may be formed from particles having a D95 particle size that is 200 micrometers or less larger than the D95 particle size of the first particulate material. For example, the second particulate material may be formed from particles having a D95 particle size that is 180 micrometers or less larger, 150 micrometers or less larger, 120 micrometers or less larger, 100 micrometers or less larger, 90 micrometers or less larger, or 80 micrometers or less larger than the D95 particle size of the first particulate material.

[0073] The first particulate material may be formed from particles having a diameter of at least 5 micrometers. For example, the first particulate material may be formed from particles having a diameter of at least 10 micrometers, at least 20 micrometers, or at least 30 micrometers.

[0074] As used herein in connection with the present invention, the term "diameter" refers to the linear distance between two points on the surface of a particle. If the linear distance between the two most distant points on the surface of the particle is 5 micrometers, then the particle will be understood to have a diameter of at least 5 micrometers. The use of the term "diameter" does not imply that the particle being characterized is spherical. If the particle is a fiber, then the "diameter" corresponds to the length of the fiber.

[0075] The first particulate material may be formed from particles having a diameter of 40 micrometers or less. For example, the first particulate material may be formed from particles having a diameter of 50 micrometers or less, 40 micrometers or less, or 35 micrometers or less.

[0076] The first particulate material may be formed from particles having a diameter of between 5 micrometers and 40 micrometers, between 10 micrometers and 35 micrometers, or between 20 micrometers and 30 micrometers.

[0077] The second particulate material may be formed from particles having a diameter of at least 50 micrometers. For example, the second particulate material may be formed from particles having a diameter of at least 80 micrometers, at least 100 micrometers, or at least 125 micrometers.

[0078] The second particulate material may be formed from particles having a diameter of 250 micrometers or less. For example, the second particulate material may be formed from particles having a diameter of 225 micrometers or less, 200 micrometers or less, or 150 micrometers or less.

[0079] The second particulate material may be formed from particles having a diameter of between 50 micrometers and 250 micrometers, between 80 micrometers and 225 micrometers, or between 100 micrometers and 125 micrometers.

[0080] The first particulate material may be formed from particles having a diameter between 5 micrometers and 40 micrometers, and the second particulate material may be formed from particles having a diameter between 50 micrometers and 250 micrometers.

[0081] The first particulate material and the second particulate material may be formed from different materials.

[0082] The first particulate material and the second particulate material may be formed from the same material.

[0083] At least one of the first particulate material and the second particulate material may comprise one or more of cellulose and microcrystalline cellulose (MCC).

[0084] The first particulate material may comprise cellulose.The first particulate material may comprise microcrystalline cellulose.The second particulate material may comprise cellulose.The second particulate material may comprise microcrystalline cellulose.

[0085] The cellulose or microcrystalline cellulose may advantageously increase the tensile strength of the aerosol-forming substrate.

[0086] Both the first particulate material and the second particulate material may comprise one or more of cellulose and microcrystalline cellulose (MCC).

[0087] The particles of the first particulate material and the second particulate material may be fibers, in which case the first particulate material may be a first fibrous material and the second particulate material may be a second fibrous material.

[0088] The particles of the first particulate material and the second particulate material may form a bimodal particle size distribution, a first peak of the bimodal distribution corresponding to the first particulate material and a second peak of the bimodal particle size distribution corresponding to the second particulate material.

[0089] As used herein with reference to the present invention, a "bimodal particle size distribution" refers to a particle size frequency distribution having two distinct modes or peaks, a first peak corresponding to a first particulate material and a second peak corresponding to a second particulate material.

[0090] The aerosol-forming substrate may be a strip.

[0091] The aerosol-forming substrate may be a rod.

[0092] The aerosol-forming substrate may be a pellet.

[0093] The aerosol-forming substrate may be a sheet.

[0094] As used herein in connection with the present invention, the term "sheet" means a laminar element having a width and length substantially greater than its thickness.

[0095] The sheet may be an assembly of sheets. As used herein in connection with the present invention, the term "assembled" means that the sheets are rolled, folded, or otherwise compressed or contracted. The sheets may be folded substantially transversely to the cylindrical axis of the aerosol-generating article.

[0096] The sheets according to the invention do not contain flowable liquids, so that users of the aerosol-generating rods and aerosol-generating articles according to the invention advantageously do not have to handle liquid agents.

[0097] Electronic cigarettes generally use liquid formulations that contain free nicotine base. Nicotine salts can be more stable than free nicotine base. As a result, the aerosol-forming substrate according to the present invention can advantageously have a longer shelf life than the liquid formulations commonly used in electronic cigarettes.

[0098] The aerosol-forming substrate may further comprise a binder.

[0099] The inclusion of a binder may advantageously facilitate the manufacture of the aerosol-forming substrate.

[0100] The inclusion of a binder may advantageously improve the homogeneity of the aerosol-forming substrate compared to an aerosol-forming substrate that does not include a binder.

[0101] The aerosol-forming substrate may include a gum binder.

[0102] The aerosol-forming substrate may comprise a natural gum binder. The aerosol-forming substrate may comprise one or more natural gum binders selected from the group consisting of guar gum, xanthan gum, natural gum and gum arabic.

[0103] The aerosol-forming substrate may have a binder content of greater than 1 weight percent. For example, the aerosol-forming substrate may have a binder content of greater than 2 weight percent, or greater than 3 weight percent.

[0104] The aerosol-forming substrate may have a binder content of 10 weight percent or less. For example, the aerosol-forming substrate may have a binder content of 8 weight percent or less, or 6 weight percent or less.

[0105] The aerosol-forming substrate may have a binder content of from 1 weight percent to 10 weight percent, from 1 weight percent to 8 weight percent, or from 1 weight percent to 6 weight percent.

[0106] The aerosol-forming substrate may have a binder content of from 2 weight percent to 10 weight percent, from 2 weight percent to 8 weight percent, or from 2 weight percent to 6 weight percent.

[0107] The aerosol-forming substrate may have a binder content of from 3 weight percent to 10 weight percent, from 3 weight percent to 8 weight percent, or from 3 weight percent to 6 weight percent.

[0108] The aerosol-forming substrate may have a binder content of about 5 percent by weight.

[0109] The binder may include carboxymethylcellulose (CMC).

[0110] Advantageously, carboxymethylcellulose can provide a faster delivery of aerosol in aerosol-forming substrates containing CMC. In particular, it has been found that aerosol-forming substrates using CMC as a binder exhibit good aerosol delivery from the first puff separated from aerosol-forming substrates using other binders.

[0111] The carboxymethylcellulose may include sodium carboxymethylcellulose. Advantageously, the inventors have discovered that sodium carboxymethylcellulose is a carboxymethylcellulose that may be particularly effective in providing rapid aerosol delivery early in the user experience.

[0112] The aerosol-forming substrate may comprise nicotine.

[0113] The nicotine may comprise one or more nicotine salts, which may be selected from the list consisting of nicotine lactate, nicotine citrate, nicotine pyruvate, nicotine bitartrate, nicotine benzoate, nicotine pectinate, nicotine alginate, and nicotine salicylate.

[0114] The nicotine may comprise an extract of tobacco.

[0115] The aerosol-forming substrate may have a nicotine content of more than 0.5 percent by weight. For example, the aerosol-forming substrate may have a nicotine content of more than 1 percent by weight, more than 2 percent by weight, more than 3 percent by weight, more than 5 percent by weight, or more than 8 percent by weight.

[0116] The aerosol-forming substrate may have a nicotine content of 10 weight percent or less. For example, the aerosol-forming substrate may have a nicotine content of 8 weight percent or less, 5 weight percent or less, 3 weight percent or less, 2 weight percent or less, or 1 weight percent or less.

[0117] The aerosol-forming substrate may have a nicotine content of from 0.5 to 10 percent by weight. For example, the aerosol-forming substrate may have a nicotine content of from 0.5 to 8 percent by weight, from 0.5 to 5 percent by weight, from 0.5 to 3 percent by weight, from 0.5 to 2 percent by weight, or from 0.5 to 1 percent by weight.

[0118] The aerosol-forming substrate may have a nicotine content of from 1 percent to 5 percent by weight. For example, the aerosol-forming substrate may have a nicotine content of from 1 percent to 3 percent by weight, or from 1 percent to 2 percent by weight. The aerosol-forming substrate may have a nicotine content of about 1.5 percent by weight.

[0119] The aerosol-forming substrate may comprise one or more carboxylic acids. Advantageously, the inclusion of one or more carboxylic acids in the aerosol-forming substrate may produce a nicotine salt.

[0120] The one or more carboxylic acids include one or more of lactic acid and levulinic acid. Advantageously, the inventors have discovered that lactic acid and levulinic acid are particularly good carboxylic acids for producing nicotine salts.

[0121] The aerosol-forming substrate may have a carboxylic acid content of greater than 0.5 weight percent. For example, the aerosol-forming substrate may have a carboxylic acid content of greater than 1 weight percent, greater than 2 weight percent, or greater than 3 weight percent.

[0122] The aerosol-forming substrate may have a carboxylic acid content of 15 weight percent or less. For example, the aerosol-forming substrate may have a carboxylic acid content of 10 weight percent or less, 5 weight percent or less, or 3 weight percent or less.

[0123] The aerosol-forming substrate may have a carboxylic acid content of from 0.5 weight percent to 15 weight percent. For example, the aerosol-forming substrate may have a carboxylic acid content of from 0.5 weight percent to 10 weight percent, from 0.5 weight percent to 5 weight percent, or from 0.5 weight percent to 3 weight percent.

[0124] The aerosol-forming substrate may have a carboxylic acid content of 2 weight percent to 15 weight percent. For example, the aerosol-forming substrate may have a carboxylic acid content of 2 weight percent to 10 weight percent, 2 weight percent to 5 weight percent, or 2 weight percent to 3 weight percent. The aerosol-forming substrate may have a carboxylic acid content of about 2.5 weight percent. The aerosol-forming substrate may have a lactic acid content of about 2.5 weight percent.

[0125] The aerosol-forming substrate may comprise one or more disaccharides, such as lactose, sucrose and trehalose, one or more sugar alcohols, such as mannitol and sorbitol, or a combination of one or more disaccharides and one or more sugar alcohols.

[0126] The aerosol-forming substrate may have a disaccharide content of greater than about 0.5 weight percent. For example, the aerosol-forming substrate may have a disaccharide content of greater than 1 weight percent, greater than 2 weight percent, or greater than 3 weight percent.

[0127] The aerosol-forming substrate may have a disaccharide content of 15 weight percent or less. For example, the aerosol-forming substrate may have a disaccharide content of 10 weight percent or less, 8 weight percent or less, or 5 weight percent or less.

[0128] The aerosol-forming substrate may have a disaccharide content of from 0.5 weight percent to 15 weight percent. For example, the aerosol-forming substrate may have a disaccharide content of from 0.5 weight percent to 10 weight percent, from 0.5 weight percent to 8 weight percent, or from 0.5 weight percent to 5 weight percent.

[0129] The aerosol-forming substrate may have a disaccharide content of 3 weight percent to 15 weight percent. For example, the aerosol-forming substrate may have a disaccharide content of 3 weight percent to 10 weight percent, or 3 weight percent to 8 weight percent. The aerosol-forming substrate may have a disaccharide content of about 2.5 weight percent. The aerosol-forming substrate may have a sucrose content of about 2.5 weight percent.

[0130] The aerosol-forming substrate may comprise cellulose reinforcing fibres.

[0131] The cellulose reinforcing fibers may have a D50 particle size of at least 0.2 millimeters, at least 0.5 millimeters, at least 0.7 millimeters, or at least 0.9 millimeters.

[0132] The cellulose reinforcing fibers may have a D50 particle size of 2.0 millimeters or less, 1.8 millimeters or less, 1.6 millimeters or less, or 1.4 millimeters or less.

[0133] For example, the cellulose reinforcing fibers may have a D50 particle size of 0.2 millimeters to 2.0 millimeters, 0.5 millimeters to 1.8 millimeters, 0.7 millimeters to 1.6 millimeters, or 0.9 millimeters to 1.4 millimeters.

[0134] The cellulose reinforcing fibers may have a D50 particle size of 0.2 millimeters to 1.8 millimeters, 0.2 millimeters to 1.6 millimeters, or 0.2 millimeters to 1.4 millimeters.

[0135] The cellulose reinforcing fibers may have a D50 particle size of 0.5 millimeters to 2.0 millimeters, 0.5 millimeters to 1.6 millimeters, or 0.5 millimeters to 1.4 millimeters.

[0136] The cellulose reinforcing fibers may have a D50 particle size of 0.7 millimeters to 2.0 millimeters, 0.7 millimeters to 1.8 millimeters, or 0.7 millimeters to 1.4 millimeters.

[0137] Advantageously, the inventors have discovered that cellulose fibres can act as reinforcing agents that are particularly effective in increasing the tensile strength of the aerosol-forming substrate, and therefore these cellulose fibres can be referred to as cellulose reinforcing fibres.

[0138] The cellulose reinforcing fibers may have a particle diameter of at least 0.2 millimeters, at least 0.5 millimeters, at least 0.7 millimeters, or at least 0.9 millimeters.

[0139] The cellulose reinforcing fibers may have a particle diameter of 2.0 millimeters or less, 1.8 millimeters or less, 1.6 millimeters or less, or 1.4 millimeters or less.

[0140] For example, the cellulose reinforcing fibers may have a particle diameter of 0.2 millimeters to 2.0 millimeters, 0.5 millimeters to 1.8 millimeters, 0.7 millimeters to 1.6 millimeters, or 0.9 millimeters to 1.4 millimeters.

[0141] The cellulose reinforcing fibers may have a particle diameter of 0.2 millimeters to 1.8 millimeters, 0.2 millimeters to 1.6 millimeters, or 0.2 millimeters to 1.4 millimeters.

[0142] The cellulose reinforcing fibers may have a particle diameter of 0.5 millimeters to 2.0 millimeters, 0.5 millimeters to 1.6 millimeters, or 0.5 millimeters to 1.4 millimeters.

[0143] The cellulose reinforcing fibers may have a particle diameter of 0.7 millimeters to 2.0 millimeters, 0.7 millimeters to 1.8 millimeters, or 0.7 millimeters to 1.4 millimeters.

[0144] The aerosol-forming substrate may have a cellulose reinforcing fiber content of more than 0.5 weight percent. For example, the aerosol-forming substrate may have a cellulose reinforcing fiber content of more than 1 weight percent, more than 2 weight percent, or more than 3 weight percent.

[0145] The aerosol-forming substrate may have a cellulose reinforcing fiber content of 15 weight percent or less. For example, the aerosol-forming substrate may have a cellulose fiber content of 10 weight percent or less, 8 weight percent or less, or 5 weight percent or less.

[0146] The aerosol-forming substrate may have a cellulose fiber content of 0.5 weight percent to 15 weight percent. For example, the aerosol-forming substrate may have a cellulose fiber content of 0.5 weight percent to 10 weight percent, 0.5 weight percent to 8 weight percent, or 0.5 weight percent to 5 weight percent.

[0147] The aerosol-forming substrate may have a cellulose fiber content of 3 to 15 percent by weight. For example, the aerosol-forming substrate may have a cellulose fiber content of 3 to 10 percent by weight, or 3 to 8 percent by weight. The aerosol-forming substrate may have a cellulose fiber content of about 6 percent by weight.

[0148] The aerosol-forming substrate may further comprise one or more of nicotine, lactic acid, and sucrose.

[0149] The first particulate material may have any density. The first particulate material may have a density of more than 0.5 grams per cubic centimeter. For example, the first particulate material may have a density of more than 1.0 grams per cubic centimeter, more than 1.5 grams per cubic centimeter, more than 3.0 grams per cubic centimeter, or more than 5.0 grams per cubic centimeter.

[0150] As mentioned above, providing a first particulate material with a relatively high density may advantageously provide improved aerosol generation over the duration of a user's experience of the aerosol-forming substrate.

[0151] The second particulate material may have any density. The second particulate material may have a density of more than 0.1 grams per cubic centimeter. For example, the first particulate material may have a density of more than 0.3 grams per cubic centimeter, more than 0.5 grams per cubic centimeter, or more than 0.6 grams per cubic centimeter.

[0152] The second particulate material may have a density of 2.0 grams per cubic centimeter or less. For example, the first particulate material may have a density of 1.5 grams per cubic centimeter or less, 1.0 grams per cubic centimeter or less, or greater than 0.8 grams per cubic centimeter.

[0153] The second particulate material may have a density of 0.1 grams per cubic centimeter to 2.0 grams per cubic centimeter. For example, the second particulate material may have a density of 0.3 grams per cubic centimeter to 1.5 grams per cubic centimeter, 0.5 grams per cubic centimeter to 1.0 grams per cubic centimeter, or 0.5 grams per cubic centimeter to 0.8 grams per cubic centimeter.

[0154] The second particulate material may have a density of between 0.6 grams per cubic centimeter and 0.8 grams per cubic centimeter.

[0155] As mentioned above, providing the second particulate material with a relatively low density may advantageously improve the physical properties of the aerosol-forming substrate making it less prone to exhibiting defects.

[0156] The aerosol-forming substrate may be tobacco-free.

[0157] According to the present invention, there is provided an aerosol-generating article comprising an aerosol-forming substrate as described above.

[0158] As used herein, the term "aerosol-generating article" refers to an article for generating an aerosol. An aerosol-generating article typically comprises an aerosol-forming substrate suitable and intended to be heated or burned to release volatile compounds capable of forming an aerosol. A conventional cigarette is ignited when a user lights one end of the cigarette and draws air through the other end. The localized heat provided by the flame and the oxygen in the air drawn through the cigarette causes the end of the cigarette to ignite, and the resulting combustion produces inhalable smoke. In contrast, in a "heated aerosol-generating article", the aerosol is generated by heating the aerosol-forming substrate, rather than by combustion of the aerosol-forming substrate. Known heated aerosol-generating articles include, for example, electrically heated aerosol-generating articles.

[0159] The aerosol-generating article may comprise a hollow cellulose acetate tube. The aerosol-generating article may comprise a spacer element. The aerosol-generating article may comprise a mouthpiece filter. The aerosol-forming substrate, the hollow cellulose acetate tube, the spacer element and the mouthpiece filter may be arranged in series. The aerosol-forming substrate, the hollow cellulose acetate tube, the spacer element and the mouthpiece filter may be arranged in coaxial alignment.

[0160] The aerosol-generating article may include tobacco paper.

[0161] The aerosol-forming substrate, the hollow cellulose acetate tube, the spacer element and the mouthpiece filter may be assembled with tobacco paper.

[0162] The aerosol-generating article may have an oral end and a distal end, and in use, a user may insert the oral end into their mouth.

[0163] The aerosol-generating article may be particularly suitable for use in an electrically operated aerosol-generating device that includes a heater for heating an aerosol-forming substrate.

[0164] The aerosol-forming substrate may be provided in the form of a plug.

[0165] The aerosol-generating article may comprise a susceptor. The susceptor may be a plurality of susceptor particles that may be deposited on or embedded within the aerosol-forming substrate. The susceptor particles may be immobilized by the aerosol-forming substrate or may remain at their initial position. The susceptor particles may be uniformly distributed in the aerosol-forming substrate. Due to the particle properties of the susceptor, heat may be generated according to the distribution of the particles in the aerosol-forming substrate. Alternatively, the susceptor may be in the form of one or more sheets, strips, pieces or rods that may be placed next to or embedded in the aerosol-forming substrate. The aerosol-forming substrate may include one or more susceptor strips.

[0166] The present invention is defined in the claims. However, below is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of any other example, embodiment, or aspect described herein.

[0167] Example 1: 1. An aerosol-forming substrate for use in an aerosol generating system, comprising a first particulate material and a second particulate material, the first particulate material being formed from particles having a D50 particle size of between 2 micrometers and 20 micrometers, and the second particulate material being formed from particles having a D50 particle size of between 50 micrometers and 80 micrometers. Example 1A: 1. An aerosol-forming substrate for use in an aerosol generating system, comprising a first particulate material and a second particulate material combined with the first particulate material, the first particulate material being formed from particles having a D50 particle size of between 2 micrometers and 20 micrometers, and the second particulate material being formed from particles having a D50 particle size of between 50 micrometers and 80 micrometers. Example 2: 1. An aerosol-forming substrate for use in an aerosol generating system, comprising a particulate material comprising a plurality of fibres, the plurality of fibres having a particle size distribution comprising a first peak corresponding to a D50 value between 2 micrometres and 20 micrometres, and a second peak corresponding to a D50 value between 50 micrometres and 80 micrometres. Example 3: An aerosol-forming substrate for use in an aerosol generating system, comprising a first particulate material and a second particulate material, the first particulate material being formed from particles having a D50 particle size of 10 micrometers and the second particulate material being formed from particles having a D50 particle size of 59 micrometers. Example 4: 1. An aerosol-forming substrate for use in an aerosol generating system, comprising a first particulate material and a second particulate material, the first particulate material being formed from particles having a D95 particle size of 10 micrometers to 60 micrometers, and the second particulate material being formed from particles having a D95 particle size of 80 micrometers to 130 micrometers. Example 5: An aerosol-forming substrate for use in an aerosol generating system, comprising a first particulate material and a second particulate material, the first particulate material being formed from particles having a D95 particle size of 33 micrometers and the second particulate material being formed from particles having a D95 particle size of 116 micrometers. Example 6: 1. An aerosol-forming substrate for use in an aerosol generating system, comprising a first particulate material and a second particulate material, the first particulate material being formed from particles having a diameter of between 5 micrometers and 40 micrometers, and the second particulate material being formed from particles having a diameter of between 50 micrometers and 250 micrometers. Example 6A: The aerosol-forming substrate according to any one of Examples 1 to 6, wherein the aerosol-forming substrate is a solid monolith. Example 7: The ratio of the mass of the first particulate material to the mass of the second particulate material in the aerosol-forming substrate is 1: The aerosol-forming substrate according to any one of Examples 1 to 6A, wherein the molecular weight of the aerosol-forming substrate is 2 or less. Example 8: The aerosol-forming substrate according to any one of Examples 1 to 7, wherein the aerosol-forming substrate further comprises one or more aerosol forming bodies. Example 9: The aerosol-forming substrate of example 8, wherein the aerosol former comprises glycerin. Example 10: An aerosol-forming substrate as described in any of Examples 1 to 9, wherein the first particulate material is formed from particles having a D50 particle size of 10 micrometers and the second particulate material is formed from particles having a D50 particle size of 59 micrometers. Example 11: 11. The aerosol-forming substrate according to any one of Examples 1 to 10, wherein the first particulate material is formed from particles having a D95 particle size of from 10 micrometers to 60 micrometers. Example 12: 12. The aerosol-forming substrate according to any one of Examples 1 to 11, wherein the second particulate material is formed from particles having a D95 particle size of between 80 micrometers and 130 micrometers. Example 13: 13. The aerosol-forming substrate of any one of Examples 1 to 12, wherein the first particulate material is formed from particles having a D95 particle size of 33 micrometers and the second particulate material is formed from particles having a D95 particle size of 116 micrometers. Example 14: The aerosol-forming substrate according to any one of Examples 1 to 13, wherein the first particulate material is formed of particles having a diameter of 5 micrometers to 40 micrometers, and the second particulate material is formed of particles having a diameter of 50 micrometers to 250 micrometers. Example 15: The aerosol-forming substrate according to any of Examples 1 to 14, wherein the first particulate material and the second particulate material are formed from different materials. Example 16: The aerosol-forming substrate according to any one of Examples 1 to 14, wherein the first particulate material and the second particulate material are formed from the same material. Example 17: 17. The aerosol-forming substrate according to any of Examples 1 to 16, wherein at least one of the first particulate material and the second particulate material comprises one or more of cellulose and microcrystalline cellulose (MCC). Example 18: 18. The aerosol-forming substrate of example 17, wherein both the first particulate material and the second particulate material comprise one or more of cellulose and microcrystalline cellulose (MCC). Example 19: The aerosol-forming substrate according to any of Examples 1 to 18, wherein the particles of the first and second particulate materials are fibers. Example 20: The aerosol-forming substrate according to any one of Examples 1 to 19, wherein the particles of the first particulate material and the second particulate material form a bimodal particle size distribution, a first peak of the bimodal particle size distribution corresponding to the first particulate material, and a second peak of the bimodal particle size distribution corresponding to the second particulate material. Example 21: The aerosol-forming substrate according to any one of Examples 1 to 20, wherein the aerosol-forming substrate is a sheet. Example 22: The aerosol-forming substrate according to any one of Examples 1 to 21, wherein the aerosol-forming substrate further comprises a binder. Example 23: The aerosol-forming substrate of Example 22, wherein the binder comprises carboxymethylcellulose (CMC). Example 24: The aerosol-forming substrate of Example 22 or Example 23, wherein the aerosol-forming substrate has a binder content of about 5 weight percent. Example 25: The aerosol-forming substrate according to any one of Examples 1 to 24, wherein the aerosol-forming substrate further comprises nicotine. Example 26: The aerosol-forming substrate of example 25, wherein the aerosol-forming substrate has a nicotine content of about 1.5 percent by weight. Example 27: The aerosol-forming substrate according to any one of Examples 1 to 26, further comprising lactic acid. Example 28: The aerosol-forming substrate of example 27, wherein the aerosol-forming substrate has a lactic acid content of about 2.5 percent by weight. Example 29: The aerosol-forming substrate according to any one of Examples 1 to 28, wherein the aerosol-forming substrate further comprises sucrose. Example 30: The aerosol-forming substrate of Example 29, wherein the aerosol-forming substrate has a sucrose content of about 2.5 percent by weight. Example 31: The aerosol-forming substrate according to any one of Examples 1 to 30, further comprising cellulose reinforcing fibers. Example 32: 32. The aerosol-forming substrate of example 31, wherein the cellulose reinforcing fibers have a D50 particle size of 0.8 millimeters to 1.5 millimeters. Example 33: The aerosol-forming substrate of example 31 or example 32, wherein the aerosol-forming substrate has a cellulose fiber content of about 6 percent by weight. Example 34: An aerosol-forming substrate according to any of examples 1 to 33, wherein the aerosol-forming substrate further comprises one or more of nicotine, lactic acid, and sucrose. Example 35: An aerosol-forming substrate according to any of examples 1 to 34, wherein the first particulate material has a density greater than 1.0 grams per cubic centimeter. Example 36: 36. The aerosol-forming substrate according to any of the preceding embodiments, wherein the second particulate material has a density of from 0.5 grams per cubic centimeter to 1.0 grams per cubic centimeter. Example 37: The ratio of the mass of the first particulate material to the mass of the second particulate material in the aerosol-forming substrate is at least 1: 5. The aerosol-forming substrate according to any one of Examples 1 to 36. Example 38: The aerosol-forming substrate according to any one of Examples 1 to 37, wherein the aerosol-forming substrate does not contain tobacco. Example 39: 39. The aerosol-forming substrate according to any one of Examples 1-38, comprising between 5 weight percent and 30 weight percent of the first particulate material and between 10 weight percent and 60 weight percent of the second particulate material. Example 40: An aerosol-generating article comprising the aerosol-forming substrate according to any one of Examples 1 to 39. Example 41: 1. A method for manufacturing an aerosol-forming substrate, the method comprising: providing a first particulate material formed of particles having a D50 particle size of between 2 micrometers and 20 micrometers; and a second particulate material formed of particles having a D50 particle size of between 50 micrometers and 80 micrometers; mixing the first particulate material and the second particles in an aqueous solution to form a slurry; casting the slurry; and drying the cast slurry to form a solid substrate. Example 42: The method of example 41, comprising drying the cast slurry to form a sheet. Example 43: The method of example 42, comprising crimping the sheet to form a plurality of strips. Example 44: 44. The method of any of embodiments 41 to 43, wherein the aqueous solution comprises a binder. Example 45: 1. A method for producing an aerosol-forming substrate, the method comprising: providing a first particulate material formed from particles having a D50 particle size of between 2 micrometers and 20 micrometers; providing a second particulate material formed from particles having a D50 particle size of between 50 micrometers and 80 micrometers; and combining the first particulate material with the second particulate material to form a solid substrate. Example 46: The method of example 45, comprising combining the first particulate material with the second particulate material to form a sheet. Example 47: The method of example 46, comprising crimping the sheet to form a plurality of strips. Example 48: The method of any of Examples 45-47, wherein combining the first particulate material with the second particulate material comprises a casting process. Example 49: 48. The method of any of examples 45-47, wherein combining the first particulate material with the second particulate material comprises pressing. Example 50: The method of any of examples 45-47, wherein combining the first particulate material with the second particulate material comprises an extrusion process. [Brief description of the drawings]

[0168] The embodiments will now be further described with reference to the following figures:

[0169] [Figure 1] FIG. 1 shows an example of an aerosol-generating article containing an aerosol-forming substrate as described herein. [Diagram 2] FIG. 2 is a plot of glycerol delivery per puff as a function of puff number for three aerosol-generating articles, each containing a different aerosol-forming substrate. [Diagram 3] FIG. 3 is a plot of nicotine delivery per puff as a function of puff number for three aerosol-generating articles, each containing a different aerosol-forming substrate. [Figure 4] FIG. 4 is an exemplary plot of particle size distribution of an aerosol-forming substrate according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0170] FIG. 1 shows an example of an aerosol-generating article 1000 that contains an aerosol-forming substrate as described herein.

[0171] 1, the aerosol-generating article 1000 includes four elements: an aerosol-forming substrate 1020, a hollow cellulose acetate tube 1030, a spacer element 1040, and a mouthpiece filter 1050. The four elements 1020, 1030, 1040, 1050 are arranged in sequential and coaxial alignment. The four elements 1020, 1030, 1040, 1050 are assembled by a cigarette paper 1060 to form the aerosol-generating article 1000.

[0172] In the example of Figure 1, the aerosol-generating article 1000 has an oral end 1012 and a distal end 1013. A user may insert the oral end 1012 into their mouth during use. The distal end 1013 is located at the opposite end of the aerosol-generating article 1000 to the oral end 1012. The example of the aerosol-generating article 1000 shown in Figure 1 is particularly suitable for use in an electrically operated aerosol generating device that includes a heater for heating an aerosol-forming substrate.

[0173] In one embodiment, when assembled, the aerosol-generating article 1000 is about 45 millimeters long, has an outer diameter of about 7.2 millimeters, and an inner diameter of about 6.9 millimeters.

[0174] In the example of Figure 1, the aerosol-forming substrate 1020 is provided in the form of a plug made by crimping sheets of the aerosol-forming substrate, which are brought together, crimped and rolled into a filter paper (not shown) to form the plug.

[0175] The aerosol-forming substrate 1020 includes a first particulate material and a second particulate material. The first particulate material is formed of particles having a D50 particle size of about 10 micrometers and a D95 particle size of about 33 micrometers. The second particulate material is formed of particles having a D50 particle size of about 59 micrometers and a D95 particle size of about 116 micrometers.

[0176] The first particulate material is formed of particles having a diameter between 5 micrometers and 40 micrometers, and the second particulate material is formed of particles having a diameter between 50 micrometers and 250 micrometers.

[0177] The ratio of the mass of the first particulate material to the mass of the second particulate material in the aerosol-forming substrate is about 1:2.

[0178] The first and second particulate materials are formed from microcrystalline cellulose (MCC).

[0179] The first particulate material has a density greater than 1.0 grams per cubic centimeter.The second particulate material has a density between 0.5 grams per cubic centimeter and 1.0 grams per cubic centimeter.

[0180] The aerosol-forming substrate 1020 comprises about 15 percent by weight of a first particulate material.

[0181] The aerosol-forming substrate 1020 comprises about 30 percent by weight of a second particulate material.

[0182] The aerosol-forming substrate 1020 further comprises approximately 30 weight percent glycerin as an aerosol former.

[0183] The aerosol-forming substrate 1020 further comprises about 5 weight percent carboxymethylcellulose as a binder.

[0184] The aerosol-forming substrate 1020 further comprises about 6 percent by weight of cellulose reinforcing fibers.

[0185] The aerosol-forming substrate 1020 further comprises about 1.5 weight percent nicotine.

[0186] The aerosol-forming substrate 1020 further comprises about 2.5 weight percent lactic acid.

[0187] The aerosol-forming substrate 1020 further comprises about 2.5 weight percent sucrose.

[0188] The aerosol-generating article 1000 as shown in Figure 1 is designed to be engaged with an aerosol-generating device for consumption. Such an aerosol-generating device includes a means for heating the aerosol-forming substrate 1020 to a sufficient temperature to form an aerosol. In general, the aerosol-generating device may comprise a heating element surrounding the aerosol-generating article 1000 adjacent to the aerosol-forming substrate 1020 or a heating element inserted into the aerosol-forming substrate 1020.

[0189] Upon engagement with the aerosol-generating device, a user draws on the mouth end 1012 of the smoking article 1000, causing the aerosol-forming substrate 1020 to heat to a temperature of approximately 260 degrees Celsius. At this temperature, volatile compounds are released from the aerosol-forming substrate 1020. These compounds condense to form an aerosol. The aerosol passes through the filter 1050 and is drawn into the user's mouth.

[0190] FIG. 2 shows the results of a study to determine the delivery of glycerol per puff as a function of puff number for three aerosol-generating articles, each containing a different aerosol-forming substrate.

[0191] The first aerosol-forming substrate is a reference substrate that was a heat stick for use in an IQOS heating device manufactured by Philip Morris Products. The reference substrate comprises cast leaf tobacco. The line corresponding to the first aerosol-forming substrate is identified as 2003.

[0192] The second aerosol-forming substrate comprises about 13.3 weight percent of the first particulate material and about 26.7 weight percent of the second particulate material. Thus, in the second aerosol-forming substrate, the ratio of the mass of the first (smaller) particulate material to the mass of the second (larger) particulate material in the aerosol-forming substrate is about 1:2. The line corresponding to the second aerosol-forming substrate is identified as 2004. The second aerosol-forming substrate is according to the present invention.

[0193] The third aerosol-forming substrate comprises about 40 weight percent of the second (larger) particulate material. The third aerosol-forming substrate does not comprise any amount of the first (smaller) particulate material. The line corresponding to the third aerosol-forming substrate is identified as 2005.

[0194] Glycerol yield in micrograms per puff is plotted on the vertical axis identified as 2001. Puff number is plotted on the horizontal axis identified as 2002.

[0195] As can be seen from the graph shown in Figure 2, it was found that the delivery of glycerol was advantageously maintained throughout the 12 puffs in the second aerosol-forming substrate 2004 according to the invention. Indeed, it was advantageously demonstrated that the second aerosol-forming substrate 2004 according to the invention exhibited a greater glycerol yield than the first reference aerosol-forming substrate 2003.

[0196] In contrast, the third aerosol-forming substrate 2005, which does not include a mixture of the first and second particulate materials, delivers significantly less glycerol over the 12 puffs.

[0197] Tests also demonstrated that a ratio of the mass of the first (smaller) particulate material to the mass of the second (larger) particulate material in the aerosol-forming substrate of about 1:2 resulted in good glycerol delivery.

[0198] FIG. 3 shows the results of a study to determine the delivery of nicotine per puff as a function of puff number for the same three aerosol-generating articles, each containing the same aerosol-forming substrate described above with reference to FIG.

[0199] The first aerosol-forming substrate, which is the reference substrate, is identified as 3003 .

[0200] A second aerosol-forming substrate according to the present invention is identified as 3004.

[0201] A third aerosol-forming substrate, not including a mixture of the first and second particulate materials, is identified as 3005 .

[0202] Nicotine yield in micrograms per puff is plotted on the vertical axis identified as 3001. Puff number is plotted on the horizontal axis identified as 3002.

[0203] As can be seen from the graph shown in Figure 3, it was found that nicotine delivery was advantageously maintained throughout the 12 puffs in the second aerosol-forming substrate 3004 according to the present invention compared to the third aerosol-forming substrate 3005 which did not include a mixture of the first and second particulate materials.

[0204] Figure 4 is an exemplary plot of particle size distribution for an aerosol-forming substrate according to the present invention. The graph shown in Figure 4 is for illustrative purposes only and is not based on actual data. Particle size is plotted on the horizontal axis identified as 4001. The frequency of a given particle size is plotted on the vertical axis identified as 4002.

[0205] As can be seen from Figure 4, the particle size distribution of the aerosol-forming substrate according to the invention exhibits a bimodal distribution pattern. The lower peak corresponds to the first (smaller) particulate material. From the lower peak the D501 diagram of the first particulate material can be determined and is identified on the graph. The D951 diagram of the first particulate material is also identified on the graph. From the higher peak the D502 diagram of the second particulate material can be determined and is identified on the graph. The D952 diagram of the second particulate material is also identified on the graph.

[0206] The ratio of the mass of the first (smaller) particulate material to the mass of the second (larger) particulate material in the aerosol-forming substrate is about 1:2. This is shown in the distribution of Figure 4 because the peak corresponding to the second particulate material is about twice as high as the first peak corresponding to the first particulate material.

Claims

1. 1. An aerosol-forming substrate for use in an aerosol-generating system, the aerosol-forming substrate being a solid, unitary body; a first particulate material; and a second particulate material; an aerosol-forming substrate, wherein the first particulate material is formed from particles having a D50 particle size of 2 micrometers to 20 micrometers, and the second particulate material is formed from particles having a D50 particle size of 50 micrometers to 80 micrometers.

2. 2. The aerosol-forming substrate according to claim 1, wherein the ratio of the mass of the first particulate material to the mass of the second particulate material in the aerosol-forming substrate is 1:2 or less.

3. 2. The aerosol-forming substrate of claim 1, wherein the first particulate material is formed from particles having a D50 particle size of 10 micrometers and the second particulate material is formed from particles having a D50 particle size of 59 micrometers.

4. 2. The aerosol-forming substrate of claim 1, wherein the first particulate material is formed from particles having a D95 particle size of 10 micrometers to 60 micrometers, and the second particulate material is formed from particles having a D95 particle size of 80 micrometers to 130 micrometers.

5. 5. The aerosol-forming substrate of claim 4, wherein the first particulate material is formed from particles having a D95 particle size of 33 micrometers and the second particulate material is formed from particles having a D95 particle size of 116 micrometers.

6. 2. The aerosol-forming substrate of claim 1, wherein the first particulate material is formed from particles having a diameter of 5 micrometers to 40 micrometers, and the second particulate material is formed from particles having a diameter of 50 micrometers to 250 micrometers.

7. 10. The aerosol-forming substrate according to claim 1, wherein the first particulate material and the second particulate material are formed from the same material.

8. 2. The aerosol-forming substrate according to claim 1, wherein at least one of the first particulate material and the second particulate material comprises one or more of cellulose and microcrystalline cellulose (MCC).

9. 10. The aerosol-forming substrate of claim 1, further comprising a binder.

10. 10. The aerosol-forming substrate of claim 1, further comprising one or more of nicotine, lactic acid, and sucrose.

11. 10. The aerosol-forming substrate of claim 1, further comprising cellulose reinforcing fibers, the cellulose reinforcing fibers having a D50 particle size of 0.8 millimeters to 1.5 millimeters.

12. 2. The aerosol-forming substrate according to claim 1, wherein the ratio of the mass of the first particulate material to the mass of the second particulate material in the aerosol-forming substrate is at least 1:

5.

13. The aerosol-forming substrate of claim 1 , wherein the aerosol-forming substrate does not contain tobacco.

14. An aerosol-generating article comprising the aerosol-forming substrate of claim 1.

15. 1. A method for producing an aerosol-forming substrate, comprising: providing a first particulate material formed of particles having a D50 particle size of between 2 micrometers and 20 micrometers; providing a second particulate material formed from particles having a D50 particle size of 50 micrometers to 80 micrometers; mixing the first particulate material and the second particles in an aqueous solution to form a slurry; casting the slurry; and drying the cast slurry to form a solid substrate.

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