CN117794397A

CN117794397A - Aerosol-forming matrix in solid unitary form formed from two particulate materials

Info

Publication number: CN117794397A
Application number: CN202280055307.4A
Authority: CN
Inventors: A·阿基斯库马尔; F·夫劳恩多弗
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2021-08-19
Filing date: 2022-08-19
Publication date: 2024-03-29
Also published as: US20240324653A1; EP4387474A1; KR20240043153A; WO2023021194A1; JP2024529679A

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 includes a first particulate material and a second particulate material. The first particulate material is formed from particles having a D50 size between 2 microns and 20 microns. The second particulate material is formed from particles having a D50 size between 50 microns and 80 microns. An aerosol-generating article comprising an aerosol-forming substrate is also provided.

Description

Aerosol-forming matrix in solid unitary form formed from two particulate materials

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-generating system, the aerosol-forming substrate comprising a first particulate material and a second particulate material, and to a method for manufacturing such an aerosol-forming substrate.

An aerosol-generating system for delivering an aerosol to a user typically comprises a nebulizer configured to generate an inhalable aerosol from an aerosol-forming substrate. Some known aerosol-generating systems include a thermal atomizer, such as an electric heater or an induction heating device. The thermal atomizer is configured to heat and vaporize an aerosol-forming substrate to generate an aerosol. A typical aerosol-forming substrate used in aerosol-generating systems is a nicotine formulation, which may be a liquid nicotine formulation comprising an aerosol-forming agent such as glycerol 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 comprise a particulate material having a certain size.

However, it has been found that solid aerosol-forming substrates comprising particulate material may be difficult to handle during manufacture due to agglomeration of the particulate material. In addition, aerosol-forming substrates comprising solid particles formed into sheets may exhibit defects such as stretch marks and slits. It has also been found that such an aerosol-forming substrate may not provide for delivery of aerosol throughout the duration of the user experience of the aerosol-forming substrate.

It is desirable to provide an aerosol-forming substrate that is easy to handle during manufacture and that does not exhibit the drawbacks observed in the prior art. It is also desirable to provide an aerosol-forming substrate that provides acceptable aerosol delivery throughout the duration of the user experience of the aerosol-forming substrate.

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 size between 2 microns and 20 microns. The second particulate material may be formed from particles having a D50 size between 50 microns and 80 microns.

According to the present invention there is provided an aerosol-forming substrate for use in an aerosol-generating system. The matrix includes a first particulate material formed from particles having a D50 size between 2 microns and 20 microns, a second particulate material formed from particles having a D50 size between 50 microns and 80 microns.

According to the present invention there is provided an aerosol-forming substrate for use in an aerosol-generating system, wherein the aerosol-forming substrate is a solid unitary body and comprises: a first particulate material formed from particles having a D50 size between 2 microns and 20 microns, and a second particulate material formed from particles having a D50 size between 50 microns and 80 microns.

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

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 size between 2 microns and 20 microns; providing a second particulate material formed from particles having a D50 size between 50 microns and 80 microns; mixing the first particulate material and the second particulate material in an aqueous solution to form a slurry; casting the slurry; and drying the cast slurry to form a solid matrix.

The inventors of the present invention have determined that aerosol-forming substrates comprising particles or "small" particles having a D50 size between 2 microns and 20 microns may disadvantageously exhibit agglomeration during manufacture and processing. In addition, in the case where the aerosol-forming substrate is formed into a thin sheet, the sheet may exhibit defects including stretch marks and slits. However, aerosol-forming substrates comprising particles having a D50 size between 2 microns and 20 microns produce high density aerosol-forming substrates. This may advantageously provide enhanced aerosol generation throughout the duration of the user experience of the aerosol-forming substrate.

On the other hand, the inventors of the present invention have determined that aerosol-forming substrates comprising particles or "large" particles having a D50 size between 50 microns and 80 microns may be advantageously easier to handle during manufacture and processing, as the particles do not exhibit the same degree of agglomeration. In addition, in the case where the aerosol-forming substrate is formed into a sheet, the sheet may be less likely to exhibit defects, allowing the particles to be more easily formed into a thin sheet. However, aerosol-forming substrates comprising particles having a D50 size between 50 and 80 microns result in lower density aerosol-forming substrates that exhibit a decrease or decay in aerosol delivery in the experience of the aerosol-forming substrate.

By providing an aerosol-forming substrate comprising a first particulate material comprising particles having a D50 size of between 2 and 20 microns and a second particulate material comprising particles having a D50 size of between 50 and 80 microns, the inventors have found that advantageous properties of both particle sizes can be achieved. At the same time, the disadvantageous properties of each particle size can be alleviated.

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

As used herein with reference to the present invention, the term "D50 size" refers to the median particle size of the particulate material. The D50 size is the particle size that divides the distribution in half, with half of the particles being larger than the D50 size and half of the particles being smaller than the D50 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 manufacturer's instructions.

In use, the aerosol-forming substrate may form part of an aerosol-generating article, which may be inserted into an aerosol-generating device. The aerosol-generating device may comprise a heater which heats the aerosol-forming substrate to release aerosol which may be delivered to a user. The aerosol-forming substrate may release the aerosol when it is 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 release an aerosol when it is 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 release an aerosol when it is heated to about 260 degrees celsius.

As used herein with reference to the present invention, the term "aerosol-forming substrate" refers to a substrate capable of generating volatile compounds upon heating that can form an aerosol. The aerosols generated by the aerosol-forming substrate may be visible or invisible to the human eye and may comprise droplets of vapor (e.g., fine particulate matter in the gaseous state, which is typically a liquid or solid at room temperature) as well as gases and condensed vapors.

The second particulate material may be formed from particles having a D50 size at least 10 microns greater than the D50 size of the first particulate material. For example, the second particulate material may be formed from particles having a D50 size at least 10 microns greater, at least 15 microns greater, at least 20 microns greater, at least 30 microns greater, at least 40 microns greater, or at least 50 microns greater than the D50 size of the first particulate material.

The second particulate material may be formed from particles having a D50 size not greater than 100 microns greater than the D50 size of the first particulate material. For example, the second particulate material may be formed from particles having a D50 size no greater than 90 microns, no greater than 80 microns, no greater than 70 microns, no greater than 60 microns, no greater than 55 microns, or no greater than 50 microns greater than the D50 size of the first particulate material.

The first particulate material and the second particulate material may be bonded together using a binder to form an aerosol-forming substrate.

The first particulate material and the second particulate material may be bonded together using pressure to form an aerosol-forming substrate.

The first particulate material and the second particulate material may be bonded together using a compression process, an extrusion process or a casting process.

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

The aerosol-forming substrate may be a sheet, strip, bar or pellet.

The aerosol-forming substrate may be manufactured by any method. The aerosol-forming substrate may be produced using a compression 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 the step of forming a slurry of the first and second particulate materials in an aqueous solution. The aqueous solution may also contain 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 by using an appropriate mold to form a solid unitary body having any desired geometry. In some examples, the cast slurry may be dried to form a sheet. The sheet may be crimped and folded to form a finished aerosol-forming substrate. In some examples, the sheet may be over-crimped to sever the sheet into a plurality of strips. In other examples, the cast slurry may be dried to form a tape, strip, or pellet.

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, the aerosol-forming substrate may comprise more of the first particulate material than the second particulate material by mass.

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 greater than 1. In other words, the aerosol-forming substrate may comprise more of the second particulate material than the first particulate material by mass.

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 greater 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 greater than 3:1, no greater than 1.

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 greater than 1:2. In other words, the second particulate material is at least twice as much as the first particulate material by mass.

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

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.

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 between 1:10 and 5:1, between 1:8 and 3:1, between 1:5 and 1, between 1:5 and 1:2, between 1:3 and 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.

The aerosol-forming substrate may have a first particulate material content of greater than 1% by weight.

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

The aerosol-forming substrate may have a first particulate material content of greater than 5 wt%, greater than 8 wt%, greater than 10 wt% or greater than 13 wt%.

The aerosol-forming substrate may have a first particulate material content of not more than 30% by weight. For example, the aerosol-forming substrate may have a first particulate material content of not greater than 25 wt%, not greater than 20 wt% or not greater than 17 wt%.

The aerosol-forming substrate may have a first particulate material content of between 5% and 30% by weight. For example, the aerosol-forming substrate may have a first particulate material content of between 5% and 25% by weight, between 5% and 20% by weight, or between 5% and 17% by weight.

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

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

The aerosol-forming substrate may have a first particulate material content of about 15% by weight.

The aerosol-forming substrate may have a second particulate material content of greater than 2% by weight.

The aerosol-forming substrate may have a second particulate material content of greater than 10 wt%, greater than 16 wt%, greater than 20 wt% or greater than 26 wt%.

The aerosol-forming substrate may have a second particulate material content of not more than 60% by weight. For example, the aerosol-forming substrate may have a second particulate material content of not greater than 50 wt%, not greater than 40 wt% or not greater than 34 wt%.

The aerosol-forming substrate may have a second particulate material content of between 10% and 60% by weight. For example, the aerosol-forming substrate may have a second particulate material content of between 10 wt% and 50 wt%, between 10 wt% and 40 wt%, or between 10 wt% and 34 wt%.

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

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

The aerosol-forming substrate may have a second particulate material content of about 30% by weight.

The aerosol-forming substrate may further comprise one or more aerosol-forming agents.

The provision of one or more aerosol-forming agents advantageously assists the aerosol-forming substrate in generating an aerosol when the aerosol-forming substrate is heated.

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 glycerol and propylene glycol.

The aerosol-forming substrate may have an aerosol former content of greater than 0.5 wt%. The aerosol-forming substrate may have an aerosol former content of greater than 10% by weight. The aerosol-forming substrate may have an aerosol former content of greater than 20 wt%. The aerosol-forming substrate may have an aerosol former content of greater than 30% by weight. The aerosol-forming substrate may have an aerosol former content of greater than 40% by weight.

The aerosol-forming substrate may have an aerosol former content of not greater than 80% by weight. The aerosol-forming substrate may have an aerosol former content of not greater than 70% by weight. The aerosol-forming substrate may have an aerosol former content of not greater than 60% by weight. The aerosol-forming substrate may have an aerosol former content of not more than 50% by weight. The aerosol-forming substrate may have an aerosol former content of not greater than 42% by weight.

In some cases, aerosol-forming substrates having an aerosol former content of greater than about 42 wt% have been found to be difficult to manufacture.

The first particulate material may be formed from particles having a D50 size between 2 microns and 20 microns, between 5 microns and 20 microns, between 10 microns and 20 microns, or between 15 microns and 20 microns.

The first particulate material may be formed from particles having a D50 size between 2 microns and 15 microns, between 2 microns and 10 microns, or between 2 microns and 5 microns.

The first particulate material may be formed from particles having a D50 size between 5 microns and 15 microns. The first particulate material may be formed from particles having a D50 size of about 10 microns.

The second particulate material may be formed from particles having a D50 size between 50 microns and 80 microns, between 60 microns and 80 microns, between 70 microns and 80 microns, or between 75 microns and 80 microns.

The second particulate material may be formed from particles having a D50 size between 50 microns and 75 microns, between 50 microns and 70 microns, or between 50 microns and 60 microns.

The second particulate material may be formed from particles having a D50 size between 55 microns and 65 microns. The second particulate material may be formed from particles having a D50 size of about 59 microns.

The first particulate material may be formed from particles having a D50 size of 10 microns and the second particulate material may be formed from particles having a D50 size of 59 microns.

It has been found that the provision of an aerosol-forming substrate comprising a first particulate material and a second particulate material having these D50 dimensions may advantageously exhibit improved handling during manufacture and good aerosol delivery during use.

The first particulate material may be formed from particles having a D95 size of at least 10 microns.

As used herein with reference to the present invention, the term "D95 size" is the size at which the proportion by mass of particles having a size below this value is 95%.

The first particulate material may be formed from particles having a D95 size of at least 15 microns, at least 20 microns, or at least 30 microns.

The first particulate material may be formed from particles having a D95 size of no greater than 60 microns, no greater than 50 microns, or no greater than 40 microns.

The first particulate material may be formed from particles having a D95 size between 10 microns and 60 microns, between 15 microns and 50 microns, between 20 microns and 40 microns, or between 30 microns and 40 microns.

The second particulate material may be formed from particles having a D95 size of at least 80 microns.

The second particulate material may be formed from particles having a D95 size of at least 90 microns, at least 100 microns, or at least 110 microns.

The second particulate material may be formed from particles having a D95 size of no greater than 130 microns, no greater than 125 microns, or no greater than 120 microns.

The second particulate material may be formed from particles having a D95 size between 80 microns and 130 microns, between 90 microns and 125 microns, between 100 microns and 120 microns, or between 110 microns and 120 microns.

The first particulate material may be formed from particles having a D95 size of 33 microns. The second particulate material may be formed from particles having a D95 size of 116 microns.

The second particulate material may be formed from particles having a D95 size at least 40 microns greater than the D95 size of the first particulate material. For example, the second particulate material may be formed from particles having a D95 size at least 50 microns greater, at least 60 microns greater, at least 70 microns greater, or at least 80 microns greater than the D95 size of the first particulate material.

The second particulate material may be formed from particles having a D95 size not greater than 200 microns greater than the D95 size of the first particulate material. For example, the second particulate material may be formed from particles having a D95 size no greater than 180 microns, no greater than 150 microns, no greater than 120 microns, no greater than 100 microns, no greater than 90 microns, or no greater than 80 microns greater than the D95 size of the first particulate material.

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

As used herein with reference to the present invention, the term "diameter" refers to the linear distance between two points on the surface of a particle. In the case where the straight line distance between two furthest points on the surface of the particle is 5 microns, it will be appreciated that the particle has a diameter of at least 5 microns. The use of the term "diameter" does not mean that the particles characterized are spherical. In the case where the particles are fibers, the "diameter" will correspond to the length of the fibers.

The first particulate material may be formed from particles having a diameter of no greater than 40 microns. For example, the first particulate material may be formed from particles having a diameter of no greater than 50 microns, no greater than 40 microns, or no greater than 35 microns.

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

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

The second particulate material may be formed from particles having a diameter of no greater than 250 microns. For example, the second particulate material may be formed from particles having a diameter of no greater than 225 microns, no greater than 200 microns, or no greater than 150 microns.

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

The first particulate material may be formed from particles having a diameter between 5 microns and 40 microns and the second particulate material may be formed from particles having a diameter between 50 microns and 250 microns.

The first particulate material and the second particulate material may be formed of different materials.

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

At least one of the first particulate material and the second particulate material may include one or more of cellulose and microcrystalline cellulose (MCC).

The first particulate material may include cellulose. The first particulate material may comprise microcrystalline cellulose. The second particulate material may include cellulose. The second particulate material may comprise microcrystalline cellulose.

Cellulose or microcrystalline cellulose may advantageously increase the tensile strength of the aerosol-forming substrate.

Both the first particulate material and the second particulate material may include one or more of cellulose and microcrystalline cellulose (MCC).

The particles of the first and second particulate materials may be fibers. In this case, the first particulate material may be a first fibrous material and the second particulate material may be a second fibrous material.

The particles of the first particulate material and the second particulate material may form a bimodal size distribution, wherein a first peak of the bimodal size distribution corresponds to the first particulate material and a second peak of the bimodal size distribution corresponds to the second particulate material.

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

The aerosol-forming substrate may be a ribbon.

The aerosol-forming substrate may be a rod.

The aerosol-forming substrate may be a pellet.

The aerosol-forming substrate may be a sheet.

As used herein with reference to the present invention, the term "sheet" means a layered element having a width and length substantially greater than its thickness.

The sheet may be an aggregate sheet. As used herein with reference to the present invention, the term "gathered" means that the sheet is curled, folded or otherwise compressed or contracted. The sheet may be folded substantially transverse to the cylindrical axis of the aerosol-generating article.

The sheet according to the invention does not comprise a flowable liquid. Thus, the aerosol-generating strip and the user of the aerosol-generating article according to the invention advantageously do not need to handle a liquid formulation.

Electronic cigarettes typically use a liquid formulation that includes free nicotine bases. The nicotine salt may be more stable than the free nicotine base. Thus, aerosol-forming substrates according to the present invention may advantageously have a longer shelf life than liquid formulations typically used in electronic cigarettes.

The aerosol-forming substrate may further comprise a binder.

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

The inclusion of a binder may advantageously improve the homogeneity of the aerosol-forming substrate compared to an aerosol-forming substrate in which the binder is not included.

The aerosol-forming substrate may comprise a glue binder.

The aerosol-forming substrate may comprise a natural gum binder. The aerosol-forming substrate may comprise one or more natural gum binders selected from guar gum, xanthan gum, natural gum and acacia gum.

The aerosol-forming substrate may have a binder content of greater than 1% by weight. For example, the aerosol-forming substrate may have a binder content of greater than 2 wt% or greater than 3 wt%.

The aerosol-forming substrate may have a binder content of not more than 10% by weight. For example, the aerosol-forming substrate may have a binder content of no greater than 8 wt% or no greater than 6 wt%.

The aerosol-forming substrate may have a binder content of between 1% and 10% by weight, between 1% and 8% by weight or between 1% and 6% by weight.

The aerosol-forming substrate may have a binder content of between 2% and 10% by weight, between 2% and 8% by weight or between 2% and 6% by weight.

The aerosol-forming substrate may have a binder content of between 3 wt% and 10 wt%, between 3 wt% and 8 wt%, or between 3 wt% and 6 wt%.

The aerosol-forming substrate may have a binder content of about 5% by weight.

The binder may include carboxymethyl cellulose (CMC).

Advantageously, carboxymethyl cellulose may provide faster delivery of aerosols in aerosol-forming substrates including CMC. In particular, aerosol-forming substrates using CMC as a binder have been found to exhibit good aerosol delivery from the first puff compared to aerosol-forming substrates using other binders.

The carboxymethyl cellulose may include sodium carboxymethyl cellulose. Advantageously, the inventors have found that sodium carboxymethyl cellulose is a carboxymethyl cellulose that may be particularly effective in providing rapid aerosol delivery from very early in the user experience.

The aerosol-forming substrate may comprise nicotine.

The nicotine may comprise one or more nicotine salts. The one or more nicotine salts may be selected from the list of: nicotine lactate, nicotine citrate, nicotine pyruvate, nicotine bitartrate, nicotine benzoate, nicotine pectate, nicotine alginate and nicotine salicylate.

The nicotine may comprise tobacco extract.

The aerosol-forming substrate may have a nicotine content of greater than 0.5% by weight. For example, the aerosol-forming substrate may have a nicotine content of greater than 1 wt%, greater than 2 wt%, greater than 3 wt%, greater than 5 wt%, or 8 wt%.

The aerosol-forming substrate may have a nicotine content of no more than 10% by weight. For example, the aerosol-forming substrate may have a nicotine content of no greater than 8 wt%, no greater than 5 wt%, no greater than 3 wt%, no greater than 2 wt%, or no greater than 1 wt%.

The aerosol-forming substrate may have a nicotine content of between 0.5% and 10% by weight. For example, the aerosol-forming substrate may have a nicotine content of between 0.5% and 8% by weight, between 0.5% and 5% by weight, between 0.5% and 3% by weight, between 0.5% and 2% by weight, or between 0.5% and 1% by weight.

The aerosol-forming substrate may have a nicotine content of between 1% and 5% by weight. For example, the aerosol-forming substrate may have a nicotine content of between 1% and 3% by weight or between 1% and 2% by weight. The aerosol-forming substrate may have a nicotine content of about 1.5% by weight.

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.

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

The aerosol-forming substrate may have a carboxylic acid content of greater than 0.5% by weight. For example, the aerosol-forming substrate may have a carboxylic acid content of greater than 1 wt%, greater than 2 wt%, or greater than 3 wt%.

The aerosol-forming substrate may have a carboxylic acid content of no greater than 15% by weight. For example, the aerosol-forming substrate may have a carboxylic acid content of no greater than 10 wt%, no greater than 5 wt%, or no greater than 3 wt%.

The aerosol-forming substrate may have a carboxylic acid content of between 0.5% and 15% by weight. For example, the aerosol-forming substrate may have a carboxylic acid content of between 0.5 wt% and 10 wt%, between 0.5 wt% and 5 wt%, or between 0.5 wt% and 3 wt%.

The aerosol-forming substrate may have a carboxylic acid content of between 2% and 15% by weight. For example, the aerosol-forming substrate may have a carboxylic acid content of between 2 wt% and 10 wt%, between 2 wt% and 5 wt%, or between 2 wt% and 3 wt%. The aerosol-forming substrate may have a carboxylic acid content of about 2.5% by weight. The aerosol-forming substrate may have a lactic acid content of about 2.5% by weight.

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.

The aerosol-forming substrate may have a disaccharide content of greater than 0.5% by weight. For example, the aerosol-forming substrate may have a disaccharide content of greater than 1 wt%, greater than 2 wt% or greater than 3 wt%.

The aerosol-forming substrate may have a disaccharide content of not more than 15% by weight. For example, the aerosol-forming substrate may have a disaccharide content of not greater than 10 wt%, not greater than 8 wt% or not greater than 5 wt%.

The aerosol-forming substrate may have a disaccharide content of between 0.5% and 15% by weight. For example, the aerosol-forming substrate may have a disaccharide content of between 0.5% and 10% by weight, between 0.5% and 8% by weight, or between 0.5% and 5% by weight.

The aerosol-forming substrate may have a disaccharide content of between 3% and 15% by weight. For example, the aerosol-forming substrate may have a disaccharide content of between 3% and 10% by weight or between 3% and 8% by weight. The aerosol-forming substrate may have a disaccharide content of about 2.5% by weight. The aerosol-forming substrate may have a sucrose content of about 2.5% by weight.

The aerosol-forming substrate may comprise cellulosic reinforcing fibres.

The cellulosic reinforcing fibers may have a D50 size of at least 0.2 millimeters, at least 0.5 millimeters, at least 0.7 millimeters, or at least 0.9 millimeters.

The cellulose reinforcing fibers may have a D50 size of not greater than 2.0 millimeters, not greater than 1.8 millimeters, not greater than 1.6 millimeters, or not greater than 1.4 millimeters.

For example, the cellulose reinforcing fibers may have a D50 size between 0.2 millimeters and 2.0 millimeters, between 0.5 millimeters and 1.8 millimeters, between 0.7 millimeters and 1.6 millimeters, or between 0.9 millimeters and 1.4 millimeters.

The cellulose reinforcing fibers may have a D50 size between 0.2 millimeters and 1.8 millimeters, between 0.2 millimeters and 1.6 millimeters, or between 0.2 millimeters and 1.4 millimeters.

The cellulose reinforcing fibers may have a D50 size between 0.5 millimeters and 2.0 millimeters, between 0.5 millimeters and 1.6 millimeters, or between 0.5 millimeters and 1.4 millimeters.

The cellulose reinforcing fibers may have a D50 size between 0.7 millimeters and 2.0 millimeters, between 0.7 millimeters and 1.8 millimeters, or between 0.7 millimeters and 1.4 millimeters.

Advantageously, the inventors have found that cellulose fibers can act as reinforcing agents that are particularly effective in increasing the tensile strength of aerosol-forming substrates. Accordingly, these cellulosic fibers may be referred to as cellulosic reinforcing fibers.

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.

The cellulose reinforcing fibers may have a particle diameter of not greater than 2.0 millimeters, not greater than 1.8 millimeters, not greater than 1.6 millimeters, or not greater than 1.4 millimeters.

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

The cellulose reinforcing fibers may have a particle diameter of between 0.2 mm and 1.8 mm, between 0.2 mm and 1.6 mm, or between 0.2 mm and 1.4 mm.

The cellulose reinforcing fibers may have a particle diameter of between 0.5 mm and 2.0 mm, between 0.5 mm and 1.6 mm, or between 0.5 mm and 1.4 mm.

The cellulose reinforcing fibers may have a particle diameter of between 0.7 mm and 2.0 mm, between 0.7 mm and 1.8 mm, or between 0.7 mm and 1.4 mm.

The aerosol-forming substrate may have a cellulose reinforcing fiber content of greater than 0.5 wt%. For example, the aerosol-forming substrate may have a cellulose reinforcing fiber content of greater than 1 wt%, greater than 2 wt%, or greater than 3 wt%.

The aerosol-forming substrate may have a cellulose reinforcing fiber content of not greater than 15 wt%. For example, the aerosol-forming substrate may have a cellulose fiber content of no greater than 10 wt%, no greater than 8 wt%, or no greater than 5 wt%.

The aerosol-forming substrate may have a cellulose fiber content of between 0.5% and 15% by weight. For example, the aerosol-forming substrate may have a cellulose fiber content of between 0.5 wt% and 10 wt%, between 0.5 wt% and 8 wt%, or between 0.5 wt% and 5 wt%.

The aerosol-forming substrate may have a cellulose fiber content of between 3% and 15% by weight. For example, the aerosol-forming substrate may have a cellulose fiber content of between 3% and 10% by weight or between 3% and 8% by weight. The aerosol-forming substrate may have a cellulose fiber content of about 6% by weight.

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

The first particulate material may have any density. The first particulate material may have a density greater than 0.5 grams per cubic centimeter. For example, the first particulate material may have a density greater than 1.0 g/cc, greater than 1.5 g/cc, greater than 3.0 g/cc, or greater than 5.0 g/cc.

As set forth above, the provision of a first particulate material having a relatively high density may advantageously provide enhanced aerosol generation throughout the duration of the user experience of the aerosol-forming substrate.

The second particulate material may have any density. The second particulate material may have a density greater than 0.1 grams per cubic centimeter. For example, the first particulate material may have a density greater than 0.3 g/cc, greater than 0.5 g/cc, or greater than 0.6 g/cc.

The second particulate material may have a density of no greater than 2.0 grams per cubic centimeter. For example, the first particulate material may have a density of no greater than 1.5 g/cc, no greater than 1.0 g/cc, or greater than 0.8 g/cc.

The second particulate material may have a density of between 0.1 g/cc and 2.0 g/cc. For example, the second particulate material may have a density of between 0.3 g/cc and 1.5 g/cc, between 0.5 g/cc and 1.0 g/cc, or between 0.5 g/cc and 0.8 g/cc.

The second particulate material may have a density of between 0.6 g/cc and 0.8 g/cc.

As set forth above, the provision of a second particulate material having a relatively low density may advantageously improve the physical properties of the aerosol-forming substrate such that it is less prone to exhibiting defects.

The aerosol-forming substrate may not comprise tobacco.

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

As used herein, the term "aerosol-generating article" refers to an article for generating an aerosol. Aerosol-generating articles generally comprise an aerosol-forming substrate adapted and intended to be heated or combusted to release volatile compounds that can form an aerosol. When a user applies a flame to one end of the cigarette and draws air through the other end, the conventional cigarette will be lit. The localized heat provided by the flame and the oxygen in the air drawn through the cigarette causes the ends of the cigarette to be lit and the resulting combustion generates inhalable smoke. In contrast, in a "heated aerosol-generating article", the aerosol is generated by heating the aerosol-forming substrate rather than by burning the aerosol-forming substrate. Known heated aerosol-generating articles include, for example, electrically heated aerosol-generating articles.

The aerosol-generating article may comprise a hollow cellulose acetate tube. The aerosol-generating article may comprise a spacing element. The aerosol-generating article may comprise a mouthpiece filter. The aerosol-forming substrate, hollow cellulose acetate tube, spacer element and mouthpiece filter may be arranged in sequence. The aerosol-forming substrate, hollow cellulose acetate tube, spacer element and mouthpiece filter may be arranged in coaxial alignment.

The aerosol-generating article may comprise cigarette paper.

The aerosol-forming substrate, hollow cellulose acetate tube, spacer element and mouthpiece filter may be assembled from cigarette paper.

The aerosol-generating article may have a mouth end and a distal end. In use, a user may insert the mouth end into his mouth.

The aerosol-generating article may be suitable for use with an electrically operated aerosol-generating device comprising a heater for heating an aerosol-forming substrate.

The aerosol-forming substrate may be provided in the form of a rod.

The aerosol-generating article may comprise a susceptor. The susceptor may be a plurality of susceptor particles, which may be deposited on or embedded within the aerosol-forming substrate. The susceptor particles may be fixed and held in an initial position by the aerosol-forming substrate. The susceptor particles may be uniformly distributed in the aerosol-forming substrate. Due to the particulate nature of the susceptor, heat may be generated according to the distribution of particles in the aerosol-forming substrate. Alternatively, the susceptor may be in the form of one or more sheets, strips, chips or strips, which may be placed beside or embedded in the aerosol-forming substrate. The aerosol-forming substrate may comprise one or more susceptor strips.

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

Example 1: an aerosol-forming substrate for use in an aerosol-generating system, comprising: a first particulate material formed from particles having a D50 size between 2 microns and 20 microns, a second particulate material formed from particles having a D50 size between 50 microns and 80 microns.

Example 1A: an aerosol-forming substrate for use in an aerosol-generating system, comprising: a first particulate material and a second particulate material bonded to the first particulate material, the first particulate material formed from particles having a D50 size between 2 microns and 20 microns, and the second particulate material formed from particles having a D50 size between 50 microns and 80 microns.

Example 2: an aerosol-forming substrate for use in an aerosol-generating system, comprising: a particulate material comprising a plurality of fibers having a size distribution comprising: a first peak corresponding to a D50 value between 2 microns and 20 microns, and a second peak corresponding to a D50 value between 50 microns and 80 microns.

Example 3: an aerosol-forming substrate for use in an aerosol-generating system, comprising: a first particulate material, a second particulate material, the first particulate material formed from particles having a D50 size of 10 microns, and the second particulate material formed from particles having a D50 size of 59 microns.

Example 4: an aerosol-forming substrate for use in an aerosol-generating system, comprising: a first particulate material, a second particulate material, the first particulate material formed from particles having a D95 size between 10 microns and 60 microns, and the second particulate material formed from particles having a D95 size between 80 microns and 130 microns.

Example 5: an aerosol-forming substrate for use in an aerosol-generating system, comprising: a first particulate material, a second particulate material, the first particulate material formed from particles having a D95 size of 33 microns, and the second particulate material formed from particles having a D95 size of 116 microns.

Example 6: an aerosol-forming substrate for use in an aerosol-generating system, comprising: a first particulate material, a second particulate material, the first particulate material formed from particles having a diameter between 5 microns and 40 microns, and the second particulate material formed from particles having a diameter between 50 microns and 250 microns.

Example 6A: an aerosol-forming substrate according to any preceding example, wherein the aerosol-forming substrate is a solid unitary body.

Example 7: an aerosol-forming substrate according to any preceding example, 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 not greater than 1:2.

Example 8: an aerosol-forming substrate according to any preceding example, wherein the aerosol-forming substrate further comprises one or more aerosol-forming agents.

Example 9: the aerosol-forming substrate of example 8, wherein the aerosol-former comprises glycerol.

Example 10: an aerosol-forming substrate according to any preceding example, wherein the first particulate material is formed from particles having a D50 size of 10 microns and the second particulate material is formed from particles having a D50 size of 59 microns.

Example 11: an aerosol-forming substrate according to any preceding example, wherein the first particulate material is formed from particles having a D95 size of between 10 microns and 60 microns.

Example 12: an aerosol-forming substrate according to any preceding example, wherein the second particulate material is formed from particles having a D95 size of between 80 microns and 130 microns.

Example 13: an aerosol-forming substrate according to any preceding example, wherein the first particulate material is formed from particles having a D95 size of 33 microns and the second particulate material is formed from particles having a D95 size of 116 microns.

Example 14: an aerosol-forming substrate according to any preceding example, wherein the first particulate material is formed from particles having a diameter of between 5 microns and 40 microns and the second particulate material is formed from particles having a diameter of between 50 microns and 250 microns.

Example 15: an aerosol-forming substrate according to any preceding example, 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: an aerosol-forming substrate according to any preceding example, 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: the aerosol-forming substrate of example 17, wherein the first particulate material and the second particulate material both comprise one or more of cellulose and microcrystalline cellulose (MCC).

Example 19: an aerosol-forming substrate according to any preceding example, wherein the particles of the first and second particulate materials are fibres.

Example 20: an aerosol-forming substrate according to any preceding example, wherein the particles of the first particulate material and the second particulate material form a bimodal size distribution, wherein a first peak of the bimodal size distribution corresponds to the first particulate material and a second peak of the bimodal size distribution corresponds to the second particulate material.

Example 21: an aerosol-forming substrate according to any preceding example, wherein the aerosol-forming substrate is a sheet.

Example 22: an aerosol-forming substrate according to any preceding example, 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 wt%.

Example 25: an aerosol-forming substrate according to any preceding example, wherein the aerosol-forming substrate further comprises nicotine.

Example 26: the aerosol-forming substrate according to example 25, wherein the aerosol-forming substrate has a nicotine content of about 1.5% by weight.

Example 27: an aerosol-forming substrate according to any preceding example, wherein the aerosol-forming substrate further comprises lactic acid.

Example 28: the aerosol-forming substrate according to example 27, wherein the aerosol-forming substrate has a lactic acid content of about 2.5 wt%.

Example 29: an aerosol-forming substrate according to any preceding example, wherein the aerosol-forming substrate further comprises sucrose.

Example 30: the aerosol-forming substrate according to example 29, wherein the aerosol-forming substrate has a sucrose content of about 2.5 wt%.

Example 31: an aerosol-forming substrate according to any preceding example, wherein the aerosol-forming substrate further comprises cellulosic reinforcing fibers.

Example 32: the aerosol-forming substrate of example 31, wherein the cellulose reinforcing fibers have a D50 size between 0.8 millimeters and 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 wt%.

Example 34: an aerosol-forming substrate according to any preceding example, 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 preceding example, wherein the first particulate material has a density of greater than 1.0 g/cc.

Example 36: an aerosol-forming substrate according to any preceding example, wherein the second particulate material has a density of between 0.5 g/cc and 1.0 g/cc.

Example 37: an aerosol-forming substrate according to any preceding example, 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.

Example 38: an aerosol-forming substrate according to any preceding example, wherein the aerosol-forming substrate does not comprise tobacco.

Example 39: an aerosol-forming substrate according to any preceding example comprising between 5% and 30% by weight of the first particulate material and between 10% and 60% by weight.

Example 40: an aerosol-generating article comprising an aerosol-forming substrate according to any preceding example.

Example 41: a method for manufacturing an aerosol-forming substrate, the method comprising: providing a first particulate material formed from particles having a D50 size between 2 microns and 20 microns; providing a second particulate material formed from particles having a D50 size between 50 microns and 80 microns; mixing the first particulate material and the second particulate material in an aqueous solution to form a slurry; casting the slurry; and drying the cast slurry to form a solid matrix.

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: the method of any one of examples 41-43, wherein the aqueous solution comprises a binder.

Example 45: a method for manufacturing an aerosol-forming substrate, the method comprising: providing a first particulate material formed from particles having a D50 size between 2 microns and 20 microns; providing a second particulate material formed from particles having a D50 size between 50 microns and 80 microns; and bonding the first particulate material with the second particulate material to form a solid matrix.

Example 46: the method of example 45, comprising bonding the first particulate material and 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 bonding the first particulate material to the second particulate material comprises a casting process.

Example 49: the method of any of examples 45-47, wherein bonding the first particulate material to the second particulate material comprises a compaction process.

Example 50: the method of any of examples 45-47, wherein bonding the first particulate material to the second particulate material comprises an extrusion process.

Examples will now be further described with reference to the accompanying drawings, in which:

fig. 1 illustrates one example of an aerosol-generating article comprising an aerosol-forming substrate as described herein;

FIG. 2 is a graph of glycerol delivery per puff as a function of puff count for three aerosol-generating articles each containing a different aerosol-forming substrate;

figure 3 is a graph of nicotine delivery per puff as a function of puff count for three aerosol-generating articles each containing a different aerosol-forming substrate; and

fig. 4 is a schematic graph of particle size distribution of an aerosol-forming substrate according to the invention.

Fig. 1 illustrates one example of an aerosol-generating article 1000 containing an aerosol-forming substrate as described herein.

In the example of fig. 1, the aerosol-generating article 1000 comprises four elements: aerosol-forming substrate 1020, hollow cellulose acetate tube 1030, spacer element 1040, and 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 from cigarette paper 1060 to form the aerosol-generating article 1000.

In the example of fig. 1, the aerosol-generating article 1000 has a mouth end 1012 and a distal end 1013. During use, a user may insert the mouth end 1012 into his or her mouth. The distal end 1013 is located at an end of the aerosol-generating article 1000 opposite the oral end 1012. This example of an aerosol-generating article 1000 illustrated in fig. 1 is particularly suitable for use with an electrically operated aerosol-generating device comprising a heater for heating an aerosol-forming substrate.

In one example, when assembled, the aerosol-generating article 1000 is about 45 millimeters in length and has an outer diameter of about 7.2 millimeters and an inner diameter of about 6.9 millimeters.

In the example of fig. 1, aerosol-forming substrate 1020 is provided in the form of a rod made by crimping a sheet of aerosol-forming substrate. The sheets are gathered, crimped and wrapped in filter paper (not shown) to form a rod.

The aerosol-forming substrate 1020 comprises a first particulate material and a second particulate material. The first particulate material is formed from particles having a D50 size of about 10 microns and a D95 size of about 33 microns. The second particulate material is formed from particles having a D50 size of about 59 microns and a D95 size of about 116 microns.

The first particulate material is formed from particles having a diameter between 5 microns and 40 microns and the second particulate material is formed from particles having a diameter between 50 microns and 250 microns.

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.

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

The first particulate material has a density greater than 1.0 g/cc. The second particulate material has a density of between 0.5 g/cc and 1.0 g/cc.

Aerosol-forming substrate 1020 comprises about 15 wt% of the first particulate material.

Aerosol-forming substrate 1020 comprises about 30 wt% of the second particulate material.

Aerosol-forming substrate 1020 further comprises about 30 wt% glycerol as an aerosol former.

Aerosol-forming substrate 1020 further comprises about 5 wt% carboxymethyl cellulose as a binder.

The aerosol-forming substrate 1020 further comprises about 6 wt% cellulosic reinforcing fibers.

The aerosol-forming substrate 1020 further comprises about 1.5% by weight nicotine.

Aerosol-forming substrate 1020 further comprises about 2.5 wt% lactic acid.

Aerosol-forming substrate 1020 further comprises about 2.5 wt% sucrose.

The aerosol-generating article 1000 as illustrated in fig. 1 is designed to be engaged with an aerosol-generating device in order to be consumed. Such aerosol-generating devices include means for heating the aerosol-forming substrate 1020 to a temperature sufficient 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.

After engagement with the aerosol-generating device, a user draws on the mouth end 1012 of the smoking article 1000 and the aerosol-forming substrate 1020 is heated to a temperature of about 260 degrees celsius. At this temperature, volatile compounds will escape from the aerosol-forming substrate 1020. These compounds condense to form aerosols. The aerosol is drawn through the filter 1050 and into the user's mouth.

Fig. 2 shows the results of a study to determine the glycerin delivery per puff as a function of the number of puffs for three aerosol-generating articles each containing a different aerosol-forming substrate.

The first aerosol-forming substrate is a reference substrate which is a hotbar for use with the 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.

The second aerosol-forming substrate comprises about 13.3 wt% of the first particulate material and about 26.7 wt% of the second particulate material. Accordingly, 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 invention.

The third aerosol-forming substrate comprises about 40 wt% 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.

Glycerol production in micrograms per puff is plotted on the vertical axis identified as 2001. The number of puffs is plotted on the horizontal axis identified as 2002.

As can be seen from the graph shown in fig. 2, it was found that in the second aerosol-forming substrate 2004 according to the invention, the delivery of glycerin advantageously lasted for all 12 puffs. In fact, it is advantageously demonstrated that the second aerosol-forming substrate 2004 according to the invention exhibits even greater glycerol production than the first reference aerosol-forming substrate 2003.

In contrast, the third aerosol-forming substrate 2005, which does not contain a mixture of the first and second particulate materials, exhibited significantly lower glycerin delivery at 12 puffs.

The experiment also demonstrated that providing a mass ratio of the first (smaller) particulate material to the second (larger) particulate material of about 1:2 in the aerosol-forming substrate resulted in advantageous glycerin delivery.

Figure 3 shows the results of a study to determine the nicotine delivery per puff as a function of the number of puffs for three aerosol-generating articles each containing the same aerosol-forming substrate described above with reference to figure 2.

The first aerosol-forming substrate that is the reference substrate is identified as 3003.

The second aerosol-forming substrate according to the invention is identified as 3004.

A third aerosol-forming substrate that does not comprise a mixture of the first and second particulate materials is identified as 3005.

Nicotine production in micrograms per puff is plotted on the vertical axis identified as 3001. The number of puffs is plotted on the horizontal axis identified as 3002.

As can be seen from the graph shown in fig. 3, it was found that the delivery of nicotine in the second aerosol-forming substrate 3004 according to the invention advantageously lasts for all 12 puffs when compared to the third aerosol-forming substrate 3005 without the mixture of the first and second particulate materials.

Fig. 4 is a schematic graph of particle size distribution of an aerosol-forming substrate according to the invention. The diagram shown in fig. 4 is for illustrative purposes only and is not based on actual data. The particle size is plotted on the horizontal axis labeled 4001. The frequency for a given particle size is plotted on the vertical axis identified as 4002.

As can be seen from fig. 4, the particle size distribution of the aerosol-forming substrate according to the invention shows a bimodal distribution pattern. The lower peak corresponds to the first (smaller) particulate material. From the lower peak, the D50 of the first particulate material can be determined ₁ And identified on the graph. D95 of first particulate material ₁ Also identified on the figure. From the higher peaks, the second particle can be determinedD50 of particulate material ₂ And identified on the graph. D95 of second particulate material ₂ Also identified on the figure.

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 demonstrated in the distribution on fig. 4, because the peak corresponding to the second particulate material is approximately twice as high as the first peak corresponding to the first particulate material.

Claims

1. An aerosol-forming substrate for use in an aerosol-generating system, wherein the aerosol-forming substrate is a solid unitary body and comprises:

a first particulate material, and

the second particulate material is present in the form of a second particulate material,

the first particulate material is formed from particles having a D50 size between 2 microns and 20 microns, and the second particulate material is formed from particles having a D50 size between 50 microns and 80 microns.

2. An 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 not greater than 1:2.

3. An aerosol-forming substrate according to any preceding claim, wherein the first particulate material is formed from particles having a D50 size of 10 microns and the second particulate material is formed from particles having a D50 size of 59 microns.

4. An aerosol-forming substrate according to any preceding claim, wherein the first particulate material is formed from particles having a D95 size of between 10 and 60 microns and the second particulate material is formed from particles having a D95 size of between 80 and 130 microns.

5. An aerosol-forming substrate according to claim 4, wherein the first particulate material is formed from particles having a D95 size of 33 microns and the second particulate material is formed from particles having a D95 size of 116 microns.

6. An aerosol-forming substrate according to any preceding claim, wherein the first particulate material is formed from particles having a diameter of between 5 and 40 microns and the second particulate material is formed from particles having a diameter of between 50 and 250 microns.

7. An aerosol-forming substrate according to any preceding claim, wherein the first particulate material and the second particulate material are formed from the same material.

8. An aerosol-forming substrate according to any preceding claim, 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. An aerosol-forming substrate according to any preceding claim, further comprising a binder.

10. An aerosol-forming substrate according to any preceding claim, further comprising one or more of nicotine, lactic acid and sucrose.

11. An aerosol-forming substrate according to any preceding claim, further comprising cellulosic reinforcing fibers, wherein the cellulosic reinforcing fibers have a D50 size of between 0.8 mm and 1.5 mm.

12. An aerosol-forming substrate according to any preceding claim, 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. An aerosol-forming substrate according to any preceding claim, wherein the aerosol-forming substrate does not comprise tobacco.

14. An aerosol-generating article comprising an aerosol-forming substrate according to any preceding claim.

15. A method for manufacturing an aerosol-forming substrate, the method comprising:

providing a first particulate material formed from particles having a D50 size between 2 microns and 20 microns;

Providing a second particulate material formed from particles having a D50 size between 50 microns and 80 microns;

mixing the first particulate material and the second particulate material in an aqueous solution to form a slurry;

casting the slurry; and

the cast slurry is dried to form a solid matrix.