Patent Description:
Aerosol generating systems for delivering an aerosol to a user typically comprise an atomiser configured to generate an inhalable aerosol from an aerosol-forming substrate. Some known aerosol generating systems comprise a thermal atomiser such as an electric heater or an inductive heating device. The thermal atomiser is configured to heat and vaporise the aerosol-forming substrate to generate an aerosol. Typical aerosol-forming substrates for use in aerosol generating systems are nicotine formulations, which may be liquid nicotine formulations comprising an aerosol former such as glycerine and propylene glycol. Alternatively, aerosol-forming substrates for use in aerosol generating systems may comprise solid components. For example, aerosol-forming substrates may comprise particulate material having a certain size.

<CIT> relates to a sheet comprising: cellulosic material comprising cellulose powder, wherein the weight ratio of cellulose powder to total cellulosic material in the sheet on a dry weight basis is greater than about <NUM>:<NUM>; and one or more nicotine salts, wherein at least about <NUM>% by weight of the one or more nicotine salts are monoprotic.

<CIT> relates to a tobacco flavoured dry powder formulation comprising a plurality of particles comprising a base material and a tobacco flavouring composition, wherein a first ratio by weight of (β-ionone + β-damascenone) to (phenol) in the tobacco flavoured dry powder formulation is greater than <NUM>. There is provided a method of producing one such tobacco flavoured powder formulation comprising the steps of: preparing a tobacco starting material; heating the tobacco starting material at an extraction temperature of between <NUM> degrees Celsius and <NUM> degrees Celsius for at least <NUM> minutes; collecting the volatile compounds released from the tobacco starting material during the heating step; forming a liquid tobacco flavouring composition comprising the collected volatile compounds; combining a base material and the liquid tobacco flavouring composition to form tobacco flavoured particles.

<CIT> relates to a container containing a powder system including a first plurality of particles having a particle size of about <NUM> micrometers or less, and a second plurality of particles having a particle size of about <NUM> micrometers or greater, and a single aperture extending through the container.

<CIT> relates to an inhalable dry powder formulation containing SAE-CD and an active agent is provided. The average particle size of the SAE-CD is large enough to preclude (for the most part) pulmonary deposition thereof.

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

It would be desirable to provide an aerosol-forming substrate which is straightforward to handle during manufacturing and which does not exhibit the defects observed in the prior art. It would also be desirable to provide an aerosol-forming substrate which provides acceptable delivery of an aerosol over the whole 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 of between <NUM> micrometres and <NUM> micrometres. The second particulate material may be formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres.

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, a second particulate material, the first particulate material being formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres, and the second particulate material being formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres.

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, and a second particulate material, the first particulate material being formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres, and the second particulate material being formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres.

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

According to the present invention, there is also provided a process for manufacturing an aerosol-forming substrate, the process comprising: providing a first particulate material, the first particulate material being formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres; providing a second particulate material, the second particulate material being formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres; mixing the first particulate material and the second particulate in an aqueous solution to form a slurry; casting the slurry; and drying the cast slurry to form a solid substrate.

The inventors of the present invention have identified that an aerosol-forming substrate comprising particles having a D50 size of between <NUM> micrometres and <NUM> micrometres, or 'small' particles, may disadvantageously exhibit agglomeration during manufacturing and processing. In addition, where 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 size between <NUM> micrometres and <NUM> micrometres result in high density aerosol-forming substrates. This may advantageously provide enhanced aerosol generation over the whole duration of the user experience of the aerosol-forming substrate.

On the other hand, the inventors of the present invention have identified that an aerosol-forming substrate comprising particles having a D50 size of between <NUM> micrometres and <NUM> micrometres, or 'large' particles, may advantageously be more straightforward to handle during manufacture and processing since the particles do not exhibit agglomeration to the same extent. In addition, where the aerosol-forming substrate is formed as a sheet, the sheet may be less likely to exhibit defects, allowing the particles to be more readily formed into a thin sheet. However, aerosol-forming substrates comprising particles having a D50 size of between <NUM> micrometres and <NUM> micrometres result in lower density aerosol-forming substrates which exhibit a drop or fading of aerosol delivery over the experience of the aerosol-forming substrate.

By providing an aerosol-forming substrate comprising a first particulate material comprising particles having a D50 size between <NUM> micrometres and <NUM> micrometres, and a second particulate material comprising particles having a D50 size of between <NUM> micrometres and <NUM> micrometres, the inventors have found that the advantageous properties of both particle sizes may be realised. At the same time, the disadvantageous properties of each particle size may be mitigated.

In other words, the inventors have found that the provision of an aerosol-forming substrate comprising a first particulate material being formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres, and a second particulate material being formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres may advantageously be straightforward to handle during manufacturing and processing and may exhibit good aerosol generation over the whole 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 which splits the distribution in half, where half of the particles are larger than the D50 size and half of the particles are 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 <NUM> laser diffraction particle size analyser in accordance with the 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 include a heater which heats the aerosol-forming substrate to release an aerosol which may be delivered to a user. The aerosol-forming substrate may release an aerosol when it is heated to at least about <NUM> degrees Celsius, at least about <NUM> degrees Celsius, at least about <NUM> degrees Celsius, at least about <NUM> degrees Celsius, or at least about <NUM> degrees Celsius. For example, the aerosol-forming substrate may release an aerosol when it is heated to between about <NUM> degrees Celsius and about <NUM> degrees Celsius, between about <NUM> degrees Celsius and about <NUM> degrees Celsius, or between about <NUM> degrees Celsius about <NUM> degrees Celsius. For example, the aerosol-forming substrate may release an aerosol when it is heated to about <NUM> degrees Celsius.

As used herein with reference to the present invention, the term "aerosol-forming substrate" refers to a substrate that is capable of producing upon heating volatile compounds, which can form an aerosol. The aerosol generated from aerosol-forming substrate may be visible to the human eye or invisible and may include vapours (for example, fine particles of substances, which are in a gaseous state, that are ordinarily liquid or solid at room temperature) as well as gases and liquid droplets of condensed vapours.

The second particulate material may be formed from particles having a D50 size which is at least <NUM> micrometres 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 which is at least <NUM> micrometres greater, <NUM> micrometres greater, <NUM> micrometres greater, <NUM> micrometres greater, <NUM> micrometres greater, or <NUM> micrometres greater than the D50 size of the first particulate material.

The second particulate material may be formed from particles having a D50 size which is no more than <NUM> micrometres 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 which is no more than <NUM> micrometres greater, <NUM> micrometres greater, <NUM> micrometres greater, <NUM> micrometres greater, <NUM> micrometres greater, or <NUM> micrometres 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 the aerosol-forming substrate.

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

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

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

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

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 cast process. The process may include steps of forming a slurry of the first and second particulate materials in an aqueous solution. The aqueous solution may further comprise 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 to form a solid unitary body having any desired geometry through use of an appropriate mould. In some examples, the cast slurry may be dried to form a sheet. The sheet may be crimped and folded to form the 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 strip, a rod or a pellet.

The aerosol-forming substrate may include 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 <NUM>. In other words, by mass, the aerosol-forming substrate may comprise more of the first particulate material than 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 no more than <NUM>. In other words, by mass, the aerosol-forming substrate may comprise more of the second particulate material than the first 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 no more than <NUM>:<NUM>. 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 <NUM>:<NUM>, no more than <NUM>.

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 <NUM>:<NUM>. In other words, by mass, there is at least twice as much of the second particulate material as the first particulate material.

The inventors have found that where more than one third by mass of the particulate material in the aerosol-forming substrate comprises the first particulate material, being formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres, the aerosol-forming substrate may exhibit defects such as cracking 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 <NUM>:<NUM>. 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 <NUM>:<NUM>, at least <NUM>:<NUM>, or at least <NUM>:<NUM>.

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 <NUM>:<NUM> and <NUM>:<NUM>, between <NUM>:<NUM> and <NUM>:<NUM>, between <NUM>:<NUM> and <NUM>, between <NUM>:<NUM> and <NUM>:<NUM>, between <NUM>:<NUM> and <NUM>:<NUM>. 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 <NUM>:<NUM>.

The aerosol-forming substrate may have a first particulate material content of greater than <NUM> weight percent.

As used herein with reference to the 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 <NUM> weight percent, greater than <NUM> weight percent, greater than <NUM> weight percent, or greater than <NUM> weight percent.

The aerosol-forming substrate may have a first particulate material content of no more than <NUM> weight percent. For example, the aerosol-forming substrate may have a first particulate material content of no more than <NUM> weight percent, no more than <NUM> weight percent, or no more than <NUM> weight percent.

The aerosol-forming substrate may have a first particulate material content of between <NUM> weight percent and <NUM> weight percent. For example, the aerosol-forming substrate may have a first particulate material content of between <NUM> weight percent and <NUM> weight percent, between <NUM> weight percent and <NUM> weight percent, or between <NUM> weight percent and <NUM> weight percent.

The aerosol-forming substrate may have a first particulate material content of between <NUM> weight percent and <NUM> weight percent. For example, the aerosol-forming substrate may have a first particulate material content of between <NUM> weight percent and <NUM> weight percent, or between <NUM> weight percent and <NUM> weight percent.

The aerosol-forming substrate may have a first particulate material content of about <NUM> weight percent.

The aerosol-forming substrate may have a second particulate material content of greater than <NUM> weight percent.

The aerosol-forming substrate may have a second particulate material content of greater than <NUM> weight percent, greater than <NUM> weight percent, greater than <NUM> weight percent, or greater than <NUM> weight percent.

The aerosol-forming substrate may have a second particulate material content of no more than <NUM> weight percent. For example, the aerosol-forming substrate may have a second particulate material content of no more than <NUM> weight percent, no more than <NUM> weight percent, or no more than <NUM> weight percent.

The aerosol-forming substrate may have a second particulate material content of between <NUM> weight percent and <NUM> weight percent. For example, the aerosol-forming substrate may have a second particulate material content of between <NUM> weight percent and <NUM> weight percent, between <NUM> weight percent and <NUM> weight percent, or between <NUM> weight percent and <NUM> weight percent.

The aerosol-forming substrate may have a second particulate material content of between <NUM> weight percent and <NUM> weight percent. For example, the aerosol-forming substrate may have a second particulate material content of between <NUM> weight percent and <NUM> weight percent, or between <NUM> weight percent and <NUM> weight percent.

The aerosol-forming substrate may have a second particulate material content of between <NUM> weight percent and <NUM> weight percent. For example, the aerosol-forming substrate may have a first particulate material content of between <NUM> weight percent and <NUM> weight percent.

The aerosol-forming substrate may have a second particulate material content of about <NUM> weight percent.

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

The provision of one or more aerosol formers advantageously helps the aerosol-forming substrate to generate an aerosol when the aerosol-forming substrate is heated.

The one or more aerosol formers may comprise glycerine. The one or more aerosol formers may comprise propylene glycol. The one or more aerosol formers may include a combination of glycerine and propylene glycol.

The aerosol-forming substrate may have an aerosol former content of greater than <NUM> weight percent. The aerosol-forming substrate may have an aerosol former content of greater than <NUM> weight percent. The aerosol-forming substrate may have an aerosol former content of greater than <NUM> weight percent weight percent. The aerosol-forming substrate may have an aerosol former content of greater than <NUM> weight percent. The aerosol-forming substrate may have an aerosol former content of greater than <NUM> weight percent.

The aerosol-forming substrate may have an aerosol former content of no more than <NUM> weight percent. The aerosol-forming substrate may have an aerosol former content of no more than <NUM> weight percent. The aerosol-forming substrate may have an aerosol former content of no more than <NUM> weight percent. The aerosol-forming substrate may have an aerosol former content of no more than <NUM> weight percent. The aerosol-forming substrate may have an aerosol former content of no more than <NUM> weight percent.

In some instances, it has been found that aerosol-forming substrates having an aerosol former content of more than about <NUM> weight percent were difficult to manufacture.

The first particulate material may be formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres, between <NUM> micrometres and <NUM> micrometres, between <NUM> micrometres and <NUM> micrometres, or between <NUM> micrometres and <NUM> micrometres.

The first particulate material may be formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres, between <NUM> micrometres and <NUM> micrometres, or between <NUM> micrometres and <NUM> micrometres.

The first particulate material may be formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres. The first particulate material may be formed from particles having a D50 size of about <NUM> micrometres.

The second particulate material may be formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres, between <NUM> micrometres and <NUM> micrometres, between <NUM> micrometres and <NUM> micrometres, or between <NUM> micrometres and <NUM> micrometres.

The second particulate material may be formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres, between <NUM> micrometres and <NUM> micrometres, or between <NUM> micrometres and <NUM> micrometres.

The second particulate material may be formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres. The second particulate material may be formed from particles having a D50 size of about <NUM> micrometres.

The first particulate material may be formed from particles having a D50 size of <NUM> micrometres, and the second particulate material may be formed from particles having a D50 size of <NUM> micrometres.

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 sizes may advantageously exhibit both improved handling during manufacture, as well as good delivery of aerosol during use.

The first particulate material may be formed from particles having a D95 size of at least <NUM> micrometres.

As used herein with reference to the present invention, the term "D95 size" is the size at which the proportion by mass of particles with sizes below this value is <NUM> percent.

The first particulate material may be formed from particles having a D95 size of at least <NUM> micrometres, at least <NUM> micrometres, or at least <NUM> micrometres.

The first particulate material may be formed from particles having a D95 size of no more than <NUM> micrometres, no more than <NUM> micrometres, or no more than <NUM> micrometres.

The first particulate material may be formed from particles having a D95 between <NUM> micrometres and <NUM> micrometres, between <NUM> micrometres and <NUM> micrometres, between <NUM> micrometres and <NUM> micrometres, or between <NUM> micrometres and <NUM> micrometres.

The second particulate material may be formed from particles having a D95 size of at least <NUM> micrometres.

The second particulate material may be formed from particles having a D95 size of at least <NUM> micrometres, at least <NUM> micrometres, or at least <NUM> micrometres.

The second particulate material may be formed from particles having a D95 size of no more than <NUM> micrometres, no more than <NUM> micrometres, or no more than <NUM> micrometres.

The second particulate material may be formed from particles having a D95 between <NUM> micrometres and <NUM> micrometres, between <NUM> micrometres and <NUM> micrometres, between <NUM> micrometres and <NUM> micrometres, or between <NUM> micrometres and <NUM> micrometres.

The first particulate material may be formed from particles having a D95 size of <NUM> micrometres. The second particulate material may be formed from particles having a D95 size of <NUM> micrometres.

The second particulate material may be formed from particles having a D95 size which is at least <NUM> micrometres 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 which is at least <NUM> micrometres greater, <NUM> micrometres greater, <NUM> micrometres greater, or <NUM> micrometres greater than the D95 size of the first particulate material.

The second particulate material may be formed from particles having a D95 size which is no more than <NUM> micrometres 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 which is no more than <NUM> micrometres greater, <NUM> micrometres greater, <NUM> micrometres greater, <NUM> micrometres greater, <NUM> micrometres greater, or <NUM> micrometres 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 <NUM> micrometres. For example, the first particulate material may be formed from particles having a diameter of at least <NUM> micrometres, at least <NUM> micrometres, or at least <NUM> micrometres.

As used herein with reference to the present invention, the term "diameter" refers to a straight line distance between two points on the surface of a particle. Where the straight line distance between the two most distant points on the surface of a particle is <NUM> micrometres, it will be understood the particle has a diameter of at least <NUM> micrometres. Use of the term "diameter" does not imply that the particles being characterized are spherical. Where the particle is a fibre, the "diameter" will correspond to the length of the fibre.

The first particulate material may be formed from particles having a diameter of no more than <NUM> micrometres. For example, the first particulate material may be formed from particles having a diameter of no more than <NUM> micrometres, no more than <NUM> micrometres, or no more than <NUM> micrometres.

The first particulate material may be formed from particles having a diameter between <NUM> micrometres and <NUM> micrometres, between <NUM> micrometres and <NUM> micrometres, or between <NUM> micrometres and <NUM> micrometres.

The second particulate material may be formed from particles having a diameter of at least <NUM> micrometres. For example, the second particulate material may be formed from particles having a diameter of at least <NUM> micrometres, at least <NUM> micrometres, or at least <NUM> micrometres.

The second particulate material may be formed from particles having a diameter of no more than <NUM> micrometres. For example, the second particulate material may be formed from particles having a diameter of no more than <NUM> micrometres, no more than <NUM> micrometres, or no more than <NUM> micrometres.

The second particulate material may be formed from particles having a diameter between <NUM> micrometres and <NUM> micrometres, between <NUM> micrometres and <NUM> micrometres, or between <NUM> micrometres and <NUM> micrometres.

The first particulate material may be formed from particles having a diameter between <NUM> micrometres and <NUM> micrometres, and the second particulate material may be formed from particles having a diameter of between <NUM> micrometres and <NUM> micrometres.

The first particulate material and the second particulate material may be formed from 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 comprise one or more of cellulose and microcrystalline cellulose (MCC).

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.

The 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 comprise one or more of cellulose and microcrystalline cellulose (MCC).

The particles of the first and second particulate materials may be fibres. Where this is the 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 with two different 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 strip.

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" denotes a laminar element having a width and length substantially greater than the thickness thereof.

The sheet may be a gathered sheet. As used herein with reference to the invention, the term "gathered" denotes that the sheet is convoluted, folded, or otherwise compressed or constricted. The sheet may be folded substantially transversely to a cylindrical axis of the aerosol generating article.

Sheets according to the invention do not comprise flowable liquid. Consequently, users of aerosol generating rods and aerosol generating articles according to the invention are advantageously not required to handle liquid formulations.

E-cigarettes typically use a liquid formulation comprising free nicotine base. Nicotine salts may be more stable than free nicotine base. Consequently, aerosol-forming substrate according to the invention may advantageously have longer shelf lives than liquid formulations typical used in e-cigarettes.

The aerosol-forming substrate may further comprise a binder.

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

Inclusion of a binder may advantageously improve the homogeneity of the aerosol-forming substrate compared to an aerosol-forming substrate in which no binder is included.

The aerosol-forming substrate may comprise a gum 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 the group consisting of guar gum, xanthan gum, natural gum, and gum arabic.

The aerosol-forming substrate may have a binder content of greater than <NUM> weight percent. For example, the aerosol-forming substrate may have a binder content of greater than <NUM> weight percent, or greater than <NUM> weight percent.

The aerosol-forming substrate may a have a binder content of no more than <NUM> weight percent. For example, the aerosol-forming substrate may have a binder content of no more than <NUM> weight percent, or no more than <NUM> weight percent.

The aerosol-forming substrate may have a binder content of between <NUM> weight percent and <NUM> weight percent, between <NUM> weight percent and <NUM> weight percent, or between <NUM> weight percent and <NUM> weight percent.

The aerosol-forming substrate may have a binder content of about <NUM> weight percent.

The binder may comprise carboxymethyl cellulose (CMC).

Advantageously, carboxymethyl cellulose may provide quicker delivery of an aerosol in aerosol-forming substrates comprising CMC. In particular, it has been found that aerosol-forming substrates using CMC as a binder exhibit good aerosol delivery from the first puff comparted to aerosol-forming substrates which use other binders.

The carboxymethyl cellulose may comprise sodium carboxymethyl cellulose. Advantageously, the present inventors have found that sodium carboxymethyl cellulose is a carboxymethyl cellulose that may be particularly effective at providing quick aerosol delivery from early on 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 consisting of nicotine lactate, nicotine citrate, nicotine pyruvate, nicotine bitartrate, nicotine benzoate, nicotine pectate, nicotine alginate, and nicotine salicylate.

The nicotine may comprise an extract of tobacco.

The aerosol-forming substrate may have a nicotine content of greater than <NUM> weight percent. For example, the aerosol-forming substrate may have a nicotine content of greater than <NUM> weight percent, greater than <NUM> weight percent, greater than <NUM> weight percent, greater than <NUM> weight percent, or <NUM> weight percent.

The aerosol-forming substrate may have a nicotine content of no more than <NUM> weight percent. For example, the aerosol-forming substrate may have a nicotine content of no more than <NUM> weight percent, no more than <NUM> weight percent, no more than <NUM> weight percent, no more than <NUM> weight percent, or no more than <NUM> weight percent.

The aerosol-forming substrate may have a nicotine content of between <NUM> weight percent and <NUM> weight percent. For example, the aerosol-forming substrate may have a nicotine content of between <NUM> weight percent and <NUM> weight percent, between <NUM> weight percent and <NUM> weight percent, between <NUM> weight percent and <NUM> weight percent, between <NUM> weight percent and <NUM> weight percent, or between <NUM> weight percent and <NUM> weight percent.

The aerosol-forming substrate may have a nicotine content of between <NUM> weight percent and <NUM> weight percent. For example, the aerosol-forming substrate may have a nicotine content of between <NUM> weight percent and <NUM> weight percent, or between <NUM> weight percent and <NUM> weight percent. The aerosol-forming substrate may have a nicotine content of about <NUM> weight percent.

The aerosol-forming substrate may comprise one or more carboxylic acids. Advantageously, including one or more carboxylic acids in the aerosol-forming substrate may create a nicotine salt.

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

The aerosol-forming substrate may have a carboxylic acid content of greater than <NUM> weight percent. For example, the aerosol-forming substrate may have a carboxylic acid content of greater than <NUM> weight percent, greater than <NUM> weight percent, or greater than <NUM> weight percent.

The aerosol-forming substrate may have a carboxylic acid content of no more than <NUM> weight percent. For example, the aerosol-forming substrate may have a carboxylic acid content of no more than <NUM> weight percent, no more than <NUM> weight percent, or no more than <NUM> weight percent.

The aerosol-forming substrate may have a carboxylic acid content of between <NUM> weight percent and <NUM> weight percent. For example, the aerosol-forming substrate may have a carboxylic acid content of between <NUM> weight percent and <NUM> weight percent, between <NUM> weight percent and <NUM> weight percent, or between <NUM> weight percent and <NUM> weight percent.

The aerosol-forming substrate may have a carboxylic acid content of between <NUM> weight percent and <NUM> weight percent. For example, the aerosol-forming substrate may have a carboxylic acid content of between <NUM> weight percent and <NUM> weight percent, between <NUM> weight percent and <NUM> weight percent, or between <NUM> weight percent and <NUM> weight percent. The aerosol-forming substrate may have a carboxylic acid content of about <NUM> weight percent. The aerosol-forming substrate may have a lactic acid content of about <NUM> weight percent.

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 <NUM> weight percent. For example, the aerosol-forming substrate may have a disaccharide content of greater than <NUM> weight percent, greater than <NUM> weight percent, or greater than <NUM> weight percent.

The aerosol-forming substrate may have a disaccharide content of no more than <NUM> weight percent. For example, the aerosol-forming substrate may have a disaccharide content of no more than <NUM> weight percent, no more than <NUM> weight percent, or no more than <NUM> weight percent.

The aerosol-forming substrate may have a disaccharide content of between <NUM> weight percent and <NUM> weight percent. For example, the aerosol-forming substrate may have a disaccharide content of between <NUM> weight percent and <NUM> weight percent, between <NUM> weight percent and <NUM> weight percent, or between <NUM> weight percent and <NUM> weight percent.

The aerosol-forming substrate may have a disaccharide content of between <NUM> weight percent and <NUM> weight percent. For example, the aerosol-forming substrate may have a disaccharide content of between <NUM> weight percent and <NUM> weight percent, or between <NUM> weight percent and <NUM> weight percent. The aerosol-forming substrate may have a disaccharide content of about <NUM> weight percent. The aerosol-forming substrate may have a sucrose content of about <NUM> weight percent.

The aerosol-forming substrate may comprise cellulose strengthening fibres.

The cellulose strengthening fibres may have a D50 size of at least <NUM> millimetres, at least <NUM> millimetres, at least <NUM> millimetres, or at least <NUM> millimetres.

The cellulose strengthening fibres may have a D50 size of no more than <NUM> millimetres, no more than <NUM> millimetres, no more than <NUM> millimetres, or no more than <NUM> millimetres.

For example, the cellulose strengthening fibres may have a D50 size of between <NUM> millimetres and <NUM> millimetres, between <NUM> millimetres and <NUM> millimetres, between <NUM> millimetres and <NUM> millimetres, or between <NUM> millimetres and <NUM> millimetres.

The cellulose strengthening fibres may have a D50 size of between <NUM> millimetres and <NUM> millimetres, between <NUM> millimetres and <NUM> millimetres, or between <NUM> millimetres and <NUM> millimetres.

Advantageously, the present inventors have found that cellulose fibres may act as a strengthening agent that is particularly effective at increasing the tensile strength of an aerosol-forming substrate. Accordingly, these cellulose fibres may be referred to as cellulose strengthening fibres.

The cellulose strengthening fibres may have a particle diameter of at least <NUM> millimetres, at least <NUM> millimetres, at least <NUM> millimetres, or at least <NUM> millimetres.

The cellulose strengthening fibres may have a particle diameter of no more than <NUM> millimetres, no more than <NUM> millimetres, no more than <NUM> millimetres, or no more than <NUM> millimetres.

For example, the cellulose strengthening fibres may have a particle diameter of between <NUM> millimetres and <NUM> millimetres, between <NUM> millimetres and <NUM> millimetres, between <NUM> millimetres and <NUM> millimetres, or between <NUM> millimetres and <NUM> millimetres.

The cellulose strengthening fibres may have a particle diameter of between <NUM> millimetres and <NUM> millimetres, between <NUM> millimetres and <NUM> millimetres, or between <NUM> millimetres and <NUM> millimetres.

The aerosol-forming substrate may have a cellulose strengthening fibre content of greater than <NUM> weight percent. For example, the aerosol-forming substrate may have a cellulose strengthening fibre content of greater than <NUM> weight percent, greater than <NUM> weight percent, or greater than <NUM> weight percent.

The aerosol-forming substrate may have a cellulose strengthening fibre content of no more than <NUM> weight percent. For example, the aerosol-forming substrate may have a cellulose fibre content of no more than <NUM> weight percent, no more than <NUM> weight percent, or no more than <NUM> weight percent.

The aerosol-forming substrate may have a cellulose fibre content of between <NUM> weight percent and <NUM> weight percent. For example, the aerosol-forming substrate may have a cellulose fibre content of between <NUM> weight percent and <NUM> weight percent, between <NUM> weight percent and <NUM> weight percent, or between <NUM> weight percent and <NUM> weight percent.

The aerosol-forming substrate may have a cellulose fibre content of between <NUM> weight percent and <NUM> weight percent. For example, the aerosol-forming substrate may have a cellulose fibre content of between <NUM> weight percent and <NUM> weight percent, or between <NUM> weight percent and <NUM> weight percent. The aerosol-forming substrate may have a cellulose fibre content of about <NUM> weight percent.

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 of greater than <NUM> grams per centimetre cubed. For example, the first particulate material may have a density of greater than <NUM> grams per centimetre cubed, greater than <NUM> grams per centimetre cubed, greater than <NUM> grams per centimetre cubed, or greater than <NUM> grams per centimetre cubed.

As set out above, the provision of a first particulate material having a relatively high density may advantageously provide enhanced aerosol generation over the whole 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 of greater than <NUM> grams per centimetre cubed. For example, the first particulate material may have a density of greater than <NUM> grams per centimetre cubed, greater than <NUM> grams per centimetre cubed, or greater than <NUM> grams per centimetre cubed.

The second particulate material may have a density of no more than <NUM> grams per centimetre cubed. For example, the first particulate material may have a density of no more than <NUM> grams per centimetre cubed, no more than <NUM> grams per centimetre cubed, or greater than <NUM> grams per centimetre cubed.

The second particulate material may have a density of between <NUM> grams per centimetre cubed and <NUM> grams per centimetre cubed. For example, the second particulate material may have a density of between <NUM> grams per centimetre cubed and <NUM> grams per centimetre cubed, between <NUM> grams per centimetre cubed and <NUM> grams per centimetre cubed, or between <NUM> grams per centimetre cubed and <NUM> grams per centimetre cubed.

The second particulate material may have a density of between <NUM> grams per centimetre cubed and <NUM> grams per centimetre cubed.

As set out above, the provision of a second particulate material having a relatively low density may advantageously improve the physical properties of the aerosol-forming substrate making it less prone to exhibit defects.

The aerosol-forming substrate may not comprise tobacco.

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

As used herein, the term "aerosol generating article" refers to an article for producing an aerosol. An aerosol generating article typically comprises an aerosol-forming substrate that is suitable and intended to be heated or combusted in order to release volatile compounds that can form an aerosol. A conventional cigarette is lit when a user applies a flame to one end of the cigarette and draws air through the other end. The localised 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 generates an inhalable smoke. By contrast, in "heated aerosol generating articles", an aerosol is generated by heating an aerosol-forming substrate and not by combusting the aerosol-forming substrate. Known heated aerosol generating articles include, for example, electrically heated aerosol generating articles.

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

The aerosol generating article may include a cigarette paper.

The aerosol-forming substrate, the hollow cellulose acetate tube, the spacer element and the mouthpiece filter may be assembled by a 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 their mouth.

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

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

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 immobilized by the aerosol-forming substrate and remain at an initial position. The susceptor particles may be homogeneously distributed in the aerosol- forming substrate. Due to the particulate nature of the susceptor, heat may be produced 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, shreds or rods that may be placed next to or embedded in the aerosol-forming substrate. The aerosol-forming substrate may comprise one or more susceptor strips.

Examples will now be further described with reference to the figure in which:.

<FIG> illustrates an example of an aerosol generating article <NUM> containing an aerosol-forming substrate as described herein.

In the example of <FIG>, the aerosol generating article <NUM> includes four elements: the aerosol-forming substrate <NUM>, a hollow cellulose acetate tube <NUM>, a spacer element <NUM>, and a mouthpiece filter <NUM>. The four elements <NUM>, <NUM>, <NUM>, <NUM> are arranged sequentially and in a coaxial alignment. The four elements <NUM>, <NUM>, <NUM>, <NUM> are assembled by a cigarette paper <NUM> to form the aerosol generating article <NUM>.

In the example of <FIG>, the aerosol generating article <NUM> has a mouth-end <NUM> and a distal end <NUM>. A user may insert the mouth-end <NUM> into their mouth during use. The distal end <NUM> is located at the opposite end of the aerosol generating article <NUM> to the mouth end <NUM>. The example of an aerosol generating article <NUM> illustrated in <FIG> is particularly suitable for use with an electrically-operated aerosol generating device comprising a heater for heating the aerosol-forming substrate.

In one example, when assembled, the aerosol generating article <NUM> is about <NUM> millimetres in length and has an outer diameter of about <NUM> millimetres and an inner diameter of about <NUM> millimetres.

In the example of <FIG>, the aerosol-forming substrate <NUM> is provided in the form of a plug made by crimping a sheet of aerosol-forming substrate. The sheet is gathered, crimped and wrapped in a filter paper (not shown) to form the plug.

The aerosol-forming substrate <NUM> comprises a first particulate material and a second particulate material. The first particulate material is formed from particles having a D50 size of about <NUM> micrometres and a D95 size of about <NUM> micrometres. The second particulate material is formed from particles having a D50 size of about <NUM> micrometres and a D95 size of about <NUM> micrometres.

The first particulate material is formed from particles having a diameter of between <NUM> micrometres and <NUM> micrometres, and the second particulate material is formed from particles having a diameter of between <NUM> micrometres and <NUM> micrometres.

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 <NUM>:<NUM>.

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

The first particulate material has a density greater than <NUM> grams per centimetre cubed. The second particulate material has a density of between <NUM> grams per centimetre cubed and <NUM> grams per centimetre cubed.

The aerosol-forming substrate <NUM> comprises about <NUM> weight percent of the first particulate material.

The aerosol-forming substrate <NUM> comprises about <NUM> weight percent of the second particulate material.

The aerosol-forming substrate <NUM> further comprises about <NUM> weight percent glycerine as an aerosol former.

The aerosol-forming substrate <NUM> further comprises about <NUM> weight percent carboxymethyl cellulose as a binder.

The aerosol-forming substrate <NUM> further comprises about <NUM> weight percent cellulose strengthening fibres.

The aerosol-forming substrate <NUM> further comprises about <NUM> weight percent nicotine.

The aerosol-forming substrate <NUM> further comprises about <NUM> weight percent lactic acid.

The aerosol-forming substrate <NUM> further comprises about <NUM> weight percent sucrose.

An aerosol generating article <NUM> as illustrated in <FIG> is designed to engage with an aerosol generating device in order to be consumed. Such an aerosol generating device includes means for heating the aerosol-forming substrate <NUM> to a sufficient temperature to form an aerosol. Typically, the aerosol generating device may comprise a heating element that surrounds the aerosol generating article <NUM> adjacent to the aerosol-forming substrate <NUM>, or a heating element that is inserted into the aerosol-forming substrate <NUM>.

Once engaged with an aerosol generating device, a user draws on the mouth-end <NUM> of the smoking article <NUM> and the aerosol-forming substrate <NUM> is heated to a temperature of about <NUM> degrees Celsius. At this temperature, volatile compounds are evolved from the aerosol-forming substrate <NUM>. These compounds condense to form an aerosol. The aerosol is drawn through the filter <NUM> and into the user's mouth.

<FIG> shows the result of a study to determine the delivery of glycerol per puff as a function of the puff number for three aerosol generating articles each containing a different aerosol-forming substrate.

The first aerosol-forming substrate is a reference substrate which was a heat stick for use with 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 <NUM>.

The second aerosol-forming substrate comprises about <NUM> weight percent of the first particulate material and about <NUM> weight percent 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 <NUM>:<NUM>. The line corresponding to the second aerosol-forming substrate is identified as <NUM>. The second aerosol-forming substrate is in accordance with the present invention.

The third aerosol-forming substrate comprises about <NUM> 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 <NUM>.

The glycerol yield in micrograms per puff is plotted on the vertical axis, identified as <NUM>. The puff number is plotted on the horizontal axis, identified as <NUM>.

As can be seen from the graph shown in <FIG>, it was found that the delivery of glycerol was advantageously sustained over the full <NUM> puffs in the second aerosol-forming substrate <NUM> according to the present invention. Indeed, it was advantageously demonstrated that the second aerosol-forming substrate <NUM> according to the present invention exhibited greater glycerol yield even than the first reference aerosol-forming substrate <NUM>.

By contrast, the third aerosol-forming substrate <NUM> which does not contain a mixture of the first and second particulate material exhibits significantly lower delivery of glycerol over the <NUM> puffs.

The test also demonstrated that providing 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 <NUM>:<NUM> results is favourable glycerol delivery.

<FIG> shows the result of a study to determine the delivery of nicotine per puff as a function of the puff number for the same three aerosol generating articles each containing the same aerosol-forming substrates described above in reference to <FIG>.

The first aerosol-forming substrate, which is a reference substrate, is identified as <NUM>.

The second aerosol-forming substrate, which is according to the present invention, is identified as <NUM>.

The third aerosol-forming substrate, which does not contain a mixture of the first and second particulate material, is identified as <NUM>.

The nicotine yield in micrograms per puff is plotted on the vertical axis, identified as <NUM>. The puff number is plotted on the horizontal axis, identified as <NUM>.

As can be seen from the graph shown in <FIG>, it was found that the delivery of nicotine was advantageously sustained over the full <NUM> puffs in the second aerosol-forming substrate <NUM> according to the present invention when compared to the third aerosol-forming substrate <NUM>, which does not contain a mixture of the first and second particulate material.

<FIG> is an illustrative plot of the particle size distribution of an aerosol-forming substrate according to the present invention. The graph shown in <FIG> is for illustrative purposes only and is not based on actual data. Particle size is plotted on the horizontal axis, identified as <NUM>. The frequency of a given particle size is plotted on the vertical axis, identified as <NUM>.

As can be seen from <FIG>, the particle size distribution of an aerosol-forming substrate according to the present invention exhibits a bimodal distribution pattern. The lower peak corresponds to the first (smaller) particulate material. From the lower peak, the D50<NUM> figure for the first particulate material may be determined and is identified on the graph. The D95<NUM> figure for the first particulate material is also identified on the graph. From the higher peak, the D50<NUM> figure for the second particulate material may be determined and is identified on the graph. The D95<NUM> figure for the second particulate material is also identified on the graph.

Claim 1:
An aerosol-forming substrate (<NUM>) for use in an aerosol generating system, wherein the aerosol-forming substrate (<NUM>) is a solid unitary body and comprises;
a first particulate material, and
a second particulate material,
the first particulate material being formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres, and the second particulate material being formed from particles having a D50 size of between <NUM> micrometres and <NUM> micrometres.