WO2023118211A1

WO2023118211A1 - Aerosol generating material comprising one or more foam forming agents

Info

Publication number: WO2023118211A1
Application number: PCT/EP2022/087091
Authority: WO
Inventors: Luis Monsalud; John-Paul Mua
Original assignee: British American Tobacco (Investments) Limited
Priority date: 2021-12-20
Filing date: 2022-12-20
Publication date: 2023-06-29

Abstract

The present invention relates to an aerosol-generating material; an aerosol- generating composition comprising the aerosol-generating material; a consumable comprising the aerosol-generating composition; a non-combustible aerosol provision system comprising the consumable and a method of forming the aerosol-generating material. The aerosol-generating material comprises: (i) one or more foam forming agents; (ii) filler; and (iii) aerosol-former material; wherein the aerosol-generating material is a foam; and wherein the aerosol-generating material has a density from about 0.02 g/cm3 to about 0.7 g/cm3.

Description

AEROSOL GENERATING MATERIAL COMPRISING ONE OR MORE FOAM FORMING AGENTS

Technical Field

The present invention relates to aerosol-generating compositions comprising a foamed aerosol-generating material; methods of making the foamed aerosolgenerating material; consumables for use within a non-combustible aerosol provision system; consumables for use within a combustible aerosol provision system, the consumables comprising the aerosol-generating composition; and non-combustible and combustible aerosol provision systems.

Background

Smoking articles such as cigarettes, cigars and the like burn tobacco during use to create tobacco smoke. Alternatives to these types of articles release an inhalable aerosol or vapour by releasing compounds from a substrate material by heating without burning. These may be referred to as non-combustible smoking articles, aerosol generating assemblies or non-combustible aerosol provision systems.

One example of such a product is a heating device which release compounds by heating, but not burning, a solid aerosolisable material. This solid aerosolisable material may, in some cases, contain a tobacco material. The heating volatilises at least one component of the material, typically forming an inhalable aerosol. These products may be referred to as heat-not-burn devices, tobacco heating devices or tobacco heating products (THP). Various different arrangements for volatilising at least one component of the solid aerosolisable material are known.

As another example, there are e-cigarette / tobacco heating product hybrid devices, also known as electronic tobacco hybrid devices. These hybrid devices contain a liquid source (which may or may not contain nicotine) which is vaporised by heating to produce an inhalable vapour or aerosol. The device additionally contains a solid aerosolisable material (which may or may not contain a tobacco material) and components of this material are entrained in the inhalable vapour or aerosol to produce the inhaled medium.

Summary of the Disclosure

In a first aspect, there is provided an aerosol-generating material comprising: (i) one or more foam forming agents;

(ii) filler; and

(iii) aerosol-former material; wherein the aerosol-generating material is a foam; and wherein the aerosol-generating material has a density from about 0.02 g/cm³ to about 0.7 g/cm³.

In one embodiment the aerosol-generating material further comprises a foam stabilising agent.

In one embodiment the aerosol-generating material further comprises an effervescent agent.

According to a further aspect of the present invention, there is provided, a method of forming an aerosol-generating material, the method comprising:

(a) providing a slurry comprising:

(i) one or more foam forming agents;

(ii) filler;

(iii) aerosol-former material; and

(iv) solvent;

(b) aerating the slurry;

(c) forming a layer of the aerated slurry;

(d) drying the slurry to form the aerosol-generating material.

According to a further aspect of the present invention, there is provided a method of forming an aerosol-generating material, the method comprising:

(a) providing a slurry comprising:

(i) one or more foam forming agents;

(ii) filler;

(iii) an effervescent agent;

(iv) aerosol-former material; and

(v) solvent;

(b) forming a layer of the slurry;

(c) drying the slurry to form the aerosol-generating material.

According to a further aspect, there is provided an aerosol-generating material obtainable or obtained by a method as described herein. According to a further aspect, there is provided an aerosol-generating composition comprising the aerosol-generating material described herein.

According to a further aspect, there is provided a consumable for use within a combustible aerosol provision system, the consumable comprising the aerosolgenerating composition as described herein.

According to a further aspect, there is provided a consumable for use within a non-combustible aerosol provision device, the consumable comprising the aerosolgenerating composition as described herein.

According to a further aspect of the present invention, there is provided a noncombustible aerosol provision system comprising the consumable as defined herein and a non-combustible aerosol provision device, the non-combustible aerosol provision device comprising an aerosol-generation device arranged to generate aerosol from the consumable when the consumable is used with the non-combustible aerosol provision device.

To the extent that they are combinable, features described herein in relation to one aspect of the invention are explicitly disclosed in combination with each and every other aspect.

Further aspects of the invention described herein may provide the use of the aerosol-generating material, the consumable, the combustible aerosol provision system or the non-combustible aerosol provision system, in the generating of an inhalable aerosol.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, given by way of example only, which is made with reference to the accompanying figures.

Brief Description of the Figures

Figure 1 shows a section view of an example of a consumable.

Figure 2 shows a perspective view of the article of Figure 1.

Figure 3 shows a sectional elevation of an example of a consumable.

Figure 4 shows a perspective view of the article of Figure 3. Figure 5 shows a perspective view of an example of a non-combustible aerosol provision system.

Figure 6 shows a section view of an example of a non-combustible aerosol provision system.

Figure 7 shows a perspective view of an example of a non-combustible aerosol provision system.

Detailed Description

The aerosol-generating compositions described herein are materials that are capable of generating aerosol, for example when heated, irradiated or energized in any other way. The aerosol-generating composition may, for example, be in the form of a solid, liquid or gel which may or may not contain nicotine. The aerosol-generating composition comprises an aerosol-generating material.

The aerosol-generating material may be an “amorphous solid”. In some embodiments, the amorphous solid is a “monolithic solid”. The aerosol-generating material may be non-fibrous or fibrous. The aerosol-generating material may be a solid material that may retain some fluid, such as liquid, within it. In some embodiments the retained fluid may be water (such as water absorbed from the surroundings of the aerosol-generating material) or the retained fluid may be solvent (such as when the aerosol-generating material is formed from a slurry). In some embodiments, the solvent may be water.

In some embodiments, the aerosol-generating composition may for example comprise from about 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, 60wt% or 70wt% of aerosol-generating material, to about 90wt%, 95wt% or 100wt% of aerosol-generating material.

In some embodiments, the aerosol-generating composition consists of aerosolgenerating material.

Aerosol-generating material

As described hereinabove, the invention provides an aerosol-generating material, wherein the aerosol-generating material comprises:

(i) one or more foam forming agents; (ii) filler; and

The aerosol-generating material may enhance sensory (e.g. organoleptic) properties of the aerosol-generating material. In particular, the aerosol that is produced by the aerosol-generating material when heated or the smoke that is produced when the article is smoked may be particularly smooth. The aerosolgenerating material may not exhibit undesirable organoleptic properties when heated or burned. Thus, the material exhibits a smooth and neutral flavour profile when smoked and does not emit overpowering or unpleasant flavours. Without wishing to be bound by theory, it is postulated that this may be due to the aerosol-generating material having a diluting effect on the aerosol or smoke that is produced.

Foam forming agent

The inventors have established that by including one or more foam forming agents, air may be incorporated into the aerosol-generating material during formation of the material. That is, by including one or more foam forming agents, the aerosolgenerating material may be provided in the form of a foam. This results in a decrease in the density of the material compared to when no foam forming agent is present. The inventors have found that this decrease in density does not adversely affect the sensory experience for the user. The invention therefore provides an aerosolgenerating material having reduced density, whilst maintaining a good sensory experience. The fill value of the aerosol-generating material may also be reduced by the inclusion of one or more foam forming agents.

The aerosol-generating material may comprise from about 5wt%, 6 wt%, 7wt%, 10wt%, 12 wt% or 15wt% to about 18 wt%, 20wt%, 25wt%, 30wt% or 35wt% of one or more foaming agents (all calculated on a dry weight basis). In exemplary embodiments, the aerosol-generating material comprises 5-35wt%, 5-30wt%, 6- 25wt%, 7-20wt% or 12-18wt% of one of more foaming agents (all calculated on a dry weight basis). The foam forming agent generally acts to trap the bubbles when the foam is formed, e.g. by aeration of the slurry.

The one or more foam forming agents may comprise hydroxypropyl methyl cellulose (HPMC), guar gum, pectin, modified starch (e.g. hydroxylated starch), maltodextrin and mixtures thereof. In some embodiments, the one or more foaming agents comprises, consists essentially of or consists of HPMC.

Filler

The aerosol-generating material may comprise from about 10wt%, 20wt%, 30 wt%, 40wt%, 50wt% or60wt% to about 85wt%, 80wt% or 75wt% of filler (all calculated on a dry weight basis). In exemplary embodiments, the aerosol-generating material comprises 10-85%, 50-80wt% or 60-75wt% filler (all calculated on a dry weight basis).

The filler may comprise one or more inorganic filler materials, such as calcium carbonate, chitosan, perlite, vermiculite, diatomaceous earth, colloidal silica, magnesium oxide, magnesium sulphate, magnesium carbonate, and suitable inorganic sorbents, such as molecular sieves. The filler may comprise one or more organic filler materials such as wood pulp, cellulose and cellulose derivatives.

In some embodiments, the filler is fibrous. For example, the filler may be a fibrous organic filler material such as wood pulp, hemp fibre, cellulose or cellulose derivatives, such as microcrystalline cellulose (MCC) and/or nanocrystalline cellulose.

Without wishing to be bound by theory, it is believed that including fibrous filler in an aerosol-generating material may increase the tensile strength of the material. This may be particularly advantageous in examples wherein the aerosol-generating material is provided as a sheet, such as when an aerosol-generating material sheet circumscribes a rod of aerosol-generating composition.

In some cases, the filler comprises maltodextrin or microcrystalline cellulose (MCC).

As would be well understood by the skilled person, microcrystalline cellulose may be formed by depolymerising cellulose by a chemical process (e.g. using an acid or enzyme). One example method for forming microcrystalline cellulose involves acid hydrolysis of cellulose, using an acid such as HCI. The cellulose produced after this treatment is crystalline (i.e. no amorphous regions remain). Suitable methods and conditions for forming microcrystalline cellulose are well-known in the art.

In some cases, the filler comprises, consists essentially of or consists of wood pulp, calcium carbonate and combinations thereof.

In some cases, the filler comprises, consists essentially of or consists of wood pulp and calcium carbonate.

In some cases, the filler comprises, consists essentially of or consists of wood pulp.

The aerosol-generating material may comprise about 1wt%, 5wt%, 10wt%, 12wt% or 13wt% to about 15wt%, 17wt% or 20wt% of wood pulp (all calculated on a dry weight basis). In exemplary embodiments, the aerosol-generating material comprises from 10-20wt%, 10-15wt% or 13-14wt% wood pulp (all calculated on a dry weight basis).

The aerosol-generating material may comprise from about 10wt%, 20wt%, 30wt%, 35wt%, 40wt% or 45wt% to about 55wt%, 60wt%, 65wt% or 70wt% of calcium carbonate (all calculated on a dry weight basis). In exemplary embodiments, the aerosol-generating material comprises 30-70wt%, 35-65wt% or 45-65wt% calcium carbonate (all calculated on a dry weight basis).

Aerosol-former material

The aerosol-generating material comprises about 1wt%, 5wt%, 10wt%, 12wt% or 13wt% to about 18wt%, 20wt%, 25wt%, 30wt%, 35wt%, 45wt%, 55wt%, 65wt%, 75wt% or 80wt% of an aerosol-former material (all calculated on a dry weight basis). In exemplary embodiments, the aerosol-generating material comprises 1-80wt%, 1- 50wt%, 5-35wt%, 10-25wt%, 12-20wt% or 13-18wt% of an aerosol-former material (all calculated on a dry weight basis).

The aerosol-former material may comprise one or more of glycerol, propylene glycol, 1 ,3-propanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1 ,3- butylene glycol, erythrito, meso-Erythritol, ethyl vanillate, ethyl laurate, a diethyl suberate, triethyl citrate, triacetin, a diacetin mixture, benzyl benzoate, benzyl phenyl acetate, tributyrin, lauryl acetate, lauric acid, myristic acid, and propylene carbonate. In some cases, the aerosol-former material comprises, consists essentially of or consists of glycerol.

Foam stabilising agent

The aerosol-generating material may comprise a foam stabilising agent. The foam stabilizing agent can reduce and even prevent breakdown of the foam after it has been formed. Put another way, the foam stabilizing agent can reduce the propensity of the surface tension of the liquid forming the bubbles of the foam to decrease.

The aerosol-generating material may comprise about 1wt%, 1.5wt% or 2wt% to about 6 wt%, 8wt% or 10wt% of foam stabilising agent (all calculated on a dry weight basis). In exemplary embodiments, the aerosol-generating material comprises 1- 10wt%, 1.5-9wt% or 2-6wt% of foam stabilising agent (calculated on a dry weight basis).

The foam stabilising agent may comprise one or more surfactants. In some embodiments, the one or more surfactants are each non-ionic, anionic or amphoteric. In some cases, the foam stabilising agent comprises sodium lauryl sulfate (SLS), Tween 60 (polyethylene glycol sorbitan monostearate), Tween 80 (polysorbate 80), Amphosol CA, Span 60 (sorbitan monosterate), Span 80 (sorbitan monooleate), lecithin or mixtures thereof.

The inventors have found that the use of a foam stabilising agent can help formation of the foamed materials of the present invention. In particular, the foam stabilising agent can stabilise bubbles formed in the slurry and therefore help prevent the bubbles from collapsing when the slurry is dried. The use of a foam stabilising agent may therefore assist with the formation of the aerosol-generating materials of the present invention.

The inventors have, however, surprisingly found that when certain foam forming agents are used (e.g. HPMC), a foam stabilising agent is not needed, and a stable foam can be formed even without the use of a foam stabilising agent. Even when not essential, a foam stabilising agent may however still be used.

Effervescent agent

The aerosol-generating material may comprise an effervescent agent. The aerosol-generating material may comprise from about 1wt%, 2 wt% or 4wt% to about 7wt%, 8wt% or 10wt% of effervescent agent (all calculated on a dry weight basis). In exemplary embodiments, the aerosol-generating material comprises 1-10wt%, 2-8wt% or 4-7wt% of effervescent agent (all calculated on a dry weight basis).

The effervescent agent may comprise calcium carbonate, sodium carbonate, sodium bicarbonate, citric acid, tartaric acid, lactic acid, acetic acid, aluminium sulfate or mixtures thereof. Calcium carbonate may be used as a filler and an effervescent agent. When calcium carbonate is used in this way, it may be present in any amount, such as those disclosed above with respect to the filler.

The inventors have found that by using an effervescent agent the slurry does not require mixing at high speed to aerate the slurry. This is particularly useful when a continuous process is used to form the aerosol-generating material.

Flavour

The aerosol-generating material may comprise about 0.1 wt%, 0.5 wt%, 1wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt% or 35wt% to about 45wt%, 50wt% or 60wt% of flavour (all calculated on a dry weight basis). In exemplary embodiments, the aerosol-generating material comprises 1 wt%, 5 wt%, 10 wt%, 20 wt%, 30wt%, or 35wt% to about 42wt%, 45wt% or 47wt% of flavour. For example, the aerosolgenerating material may comprise 1-60wt%, 1-45wt%, 10-45wt%, 20-50wt%, 30- 50wt%, 30-45wt% or 35-45wt% of flavour.

As used herein, the terms “flavour” and “flavourant” refer to materials which, where local regulations permit, may be used to create a desired taste, aroma, or other somatosensorial sensation in a product for adult consumers. They may include naturally occurring flavour materials, botanicals, extracts of botanicals, synthetically obtained materials, or combinations thereof (e.g., tobacco, cannabis, licorice (liquorice), hydrangea, eugenol, Japanese white bark magnolia leaf, chamomile, fenugreek, clove, maple, matcha, menthol, Japanese mint, aniseed (anise), cinnamon, turmeric, Indian spices, Asian spices, herb, Wintergreen, cherry, berry, red berry, cranberry, peach, apple, orange, mango, clementine, lemon, lime, tropical fruit, papaya, rhubarb, grape, durian, dragon fruit, cucumber, blueberry, mulberry, citrus fruits, Drambuie, bourbon, scotch, whiskey, gin, tequila, rum, spearmint, peppermint, lavender, aloe vera, cardamom, celery, cascarilla, nutmeg, sandalwood, bergamot, geranium, khat, naswar, betel, shisha, pine, honey essence, rose oil, vanilla, lemon oil, orange oil, orange blossom, cherry blossom, cassia, caraway, cognac, jasmine, ylang- ylang, sage, fennel, wasabi, piment, ginger, coriander, coffee, hemp, a mint oil from any species of the genus Mentha, eucalyptus, star anise, cocoa, lemongrass, rooibos, flax, ginkgo biloba, hazel, hibiscus, laurel, mate, orange skin, rose, tea such as green tea or black tea, thyme, juniper, elderflower, basil, bay leaves, cumin, oregano, paprika, rosemary, saffron, lemon peel, mint, beefsteak plant, curcuma, cilantro, myrtle, cassis, valerian, pimento, mace, damien, marjoram, olive, lemon balm, lemon basil, chive, carvi, verbena, tarragon, limonene, thymol, camphene), flavour enhancers, bitterness receptor site blockers, sensorial receptor site activators or stimulators, sugars and/or sugar substitutes (e.g., sucralose, acesulfame potassium, aspartame, saccharine, cyclamates, lactose, sucrose, glucose, fructose, sorbitol, or mannitol), and other additives such as charcoal, chlorophyll, minerals, botanicals, or breath freshening agents. They may be imitation, synthetic or natural ingredients or blends thereof. They may be in any suitable form, for example, liquid such as an oil, solid such as a powder, or gas.

In some embodiments, the flavour comprises flavour components of cucumber, blueberry, citrus fruits and/or redberry.

In some embodiments, the flavour comprises eugenol.

In some embodiments, the flavour comprises flavour components extracted from tobacco.

In some embodiments, the flavour may comprise a sensate, which is intended to achieve a somatosensorial sensation which are usually chemically induced and perceived by the stimulation of the fifth cranial nerve (trigeminal nerve), in addition to or in place of aroma or taste nerves, and these may include agents providing heating, cooling, tingling, numbing effect. A suitable heat effect agent may be, but is not limited to, vanillyl ethyl ether and a suitable cooling agent may be, but not limited to eucalyptol or WS-3 (/V-ethyl-2-isopropyl-5-methylcyclohexanecarboxamide).

In some embodiments, the aerosol-generating composition comprises a flavour. In some embodiments, the flavour is applied by spraying directly onto the composition once the composition is formed.

The aerosol-generating material may have any suitable water content, such as from 1wt % to 15wt%. Suitably, the water content of the aerosol-generating material may be from about 5wt%, 7wt% or 9wt% to about 15wt%, 13wt% or 11wt% (wet weight basis) (WWB). The water content of the aerosol-generating material may, for example, be determined by Karl-Fischer-titration or Gas Chromatography with Thermal Conductivity Detector (GC-TCD).

Colourant

The aerosol-generating material may comprise a colourant. The addition of a colourant may alter the visual appearance of the aerosol-generating material. The presence of colourant in the aerosol-generating material may enhance the visual appearance of the aerosol-generating material and the aerosol-generating composition. By adding a colourant to the aerosol-generating material, the aerosolgenerating material may be colour-matched to other components of the aerosolgenerating composition or to other components of an article comprising the aerosolgenerating material.

A variety of colourants may be used depending on the desired colour of the aerosol-generating material. The colour of aerosol-generating material may be, for example, white, green, red, purple, blue, brown or black. Other colours are also envisaged. Natural or synthetic colourants, such as natural or synthetic dyes, foodgrade colourants and pharmaceutical-grade colourants may be used. In certain embodiments, the colourant is caramel, which may confer the aerosol-generating material with a brown appearance. In such embodiments, the colour of the aerosolgenerating material may be similar to the colour of other components (such as tobacco material) in an aerosol-generating composition comprising the aerosol-generating material. In some embodiments, the addition of a colourant to the aerosol-generating material renders it visually indistinguishable from other components in the aerosolgenerating composition.

The colourant may be incorporated during the formation of the aerosolgenerating material (e.g. when forming a slurry comprising the materials that form the aerosol-generating material) or it may be applied to the aerosol-generating material after its formation (e.g. by spraying it onto the aerosol-generating material). Active substance

In some embodiments, the aerosol-generating material additionally comprises an active substance. In some embodiments, the aerosol-generating composition comprises an active substance.

The active substance as used herein may be a physiologically active material, which is a material intended to achieve or enhance a physiological response. The active substance may for example be selected from nutraceuticals, nootropics, psychoactives. The active substance may be naturally occurring or synthetically obtained. The active substance may comprise for example nicotine, caffeine, taurine, theine, vitamins such as B6 or B12 or C, melatonin, cannabinoids, or constituents, derivatives, or combinations thereof. The active substance may comprise one or more constituents, derivatives or extracts of tobacco, cannabis or another botanical.

In some embodiments, the active substance comprises nicotine. In some embodiments, the active substance comprises caffeine, melatonin or vitamin B12.

In some embodiments, the active substance may comprise one or more constituents, derivatives or extracts of cannabis, such as one or more cannabinoids or terpenes.

In some embodiments, the active substance may comprise or be derived from one or more botanicals or constituents, derivatives or extracts thereof. As used herein, the term "botanical" includes any material derived from plants including, but not limited to, extracts, leaves, bark, fibres, stems, roots, seeds, flowers, fruits, pollen, husk, shells or the like. Alternatively, the material may comprise an active compound naturally existing in a botanical, obtained synthetically. The material may be in the form of liquid, gas, solid, powder, dust, crushed particles, granules, pellets, shreds, strips, sheets, or the like. Example botanicals are tobacco, eucalyptus, star anise, hemp, cocoa, cannabis, fennel, lemongrass, peppermint, spearmint, rooibos, chamomile, flax, ginger, ginkgo biloba, hazel, hibiscus, laurel, licorice (liquorice), matcha, mate, orange skin, papaya, rose, sage, tea such as green tea or black tea, thyme, clove, cinnamon, coffee, aniseed (anise), basil, bay leaves, cardamom, coriander, cumin, nutmeg, oregano, paprika, rosemary, saffron, lavender, lemon peel, mint, juniper, elderflower, vanilla, Wintergreen, beefsteak plant, curcuma, turmeric, sandalwood, cilantro, bergamot, orange blossom, myrtle, cassis, valerian, pimento, mace, damien, marjoram, olive, lemon balm, lemon basil, chive, carvi, verbena, tarragon, geranium, mulberry, ginseng, theanine, theacrine, maca, ashwagandha, damiana, guarana, chlorophyll, baobab or any combination thereof. The mint may be chosen from the following mint varieties: Mentha Arventis, Mentha c.v., Mentha niliaca, Mentha piperita, Mentha piperita citrata c.v., Mentha piperita c.v, Mentha spicata crispa, Mentha cardifolia, Memtha longifolia, Mentha suaveolens variegata, Mentha pulegium, Mentha spicata c.v. and Mentha suaveolens

In some embodiments, the active substance comprises or is derived from one or more botanicals or constituents, derivatives or extracts thereof and the botanical is tobacco.

In some embodiments, the active substance comprises or derived from one or more botanicals or constituents, derivatives or extracts thereof and the botanical is selected from eucalyptus, star anise, cocoa and hemp.

In some embodiments, the active substance comprises or derived from one or more botanicals or constituents, derivatives or extracts thereof and the botanical is selected from rooibos and fennel.

For example, in some cases, the aerosol-generating composition additionally comprises a tobacco material and/or nicotine. In some cases, the aerosol-generating composition may comprise 5-60wt% (calculated on a dry weight basis) of a tobacco material and/or nicotine. In some cases, the aerosol-generating composition may comprise from about 1wt%, 5wt%, 10wt%, 15wt%, 20wt% or 25wt% to about 70wt%, 60wt%, 50wt%, 45wt%, 40wt%, 35wt%, or 30wt% (calculated on a dry weight basis) of an active substance. In some cases, the aerosol-generating composition may comprise from about 1wt%, 5wt%, 10wt%, 15wt%, 20wt% or 25wt% to about 70wt%, 60wt%, 50wt%, 45wt%, 40wt%, 35wt%, or 30wt% (calculated on a dry weight basis) of a tobacco material. For example, the aerosol-generating composition may comprise 1-70wt%, 10-50wt%, 15-40wt% or 20-35wt% of a tobacco material. In some cases, the aerosol-generating composition may comprise from about 1wt%, 2wt%, 3wt% or 4wt% to about 20wt%, 18wt%, 15wt% or 12wt% (calculated on a dry weight basis) of nicotine. For example, the aerosol-generating composition may comprise 1-20wt%, 2-18wt% or

In some cases, the aerosol-generating composition comprises an active substance such as tobacco extract. In some cases, the aerosol-generating composition may comprise 5-60wt% (calculated on a dry weight basis) of tobacco extract. In some cases, the aerosol-generating composition may comprise from about 5wt%, 10wt%, 15wt%, 20wt% or 25wt% to about 60wt%, 50wt%, 45wt%, 40wt%, 35wt%, or 30wt% (calculated on a dry weight basis) tobacco extract. For example, the aerosol-generating composition may comprise 10-50wt%, 15-40wt% or 20-35wt% of tobacco extract. The tobacco extract may contain nicotine at a concentration such that the aerosol-generating composition comprises 1 wt% 1 ,5wt%, 2wt% or 2.5wt% to about 10wt%, 8wt%, 6wt%, 5wt%, 4.5wt% or 4wt% (calculated on a dry weight basis) of nicotine. In some embodiments, the aerosol-generating composition may comprise 1-10 wt%, 2.5-8 wt% or 2-6wt% nicotine. In some cases, there may be no nicotine in the aerosol-generating composition other than that which results from the tobacco extract.

In some embodiments, the aerosol-generating composition comprises no tobacco material but does comprise nicotine. In some such cases, the aerosolgenerating composition may comprise from about 1 wt%, 2wt%, 3wt% or 4wt% to about 20wt%, 18wt%, 15wt% or 12wt% (calculated on a dry weight basis) of nicotine. For example, the aerosol-generating composition may comprise 1-20wt%, 2-18wt% or 3- 12wt% of nicotine.

The aerosol-generating composition may comprise an acid. The acid may be an organic acid. In some of these embodiments, the acid may be at least one of a monoprotic acid, a diprotic acid and a triprotic acid. In some such embodiments, the acid may contain at least one carboxyl functional group. In some such embodiments, the acid may be at least one of an alpha-hydroxy acid, carboxylic acid, dicarboxylic acid, tricarboxylic acid and keto acid. In some such embodiments, the acid may be an alpha-keto acid.

In some such embodiments, the acid may be at least one of succinic acid, lactic acid, benzoic acid, citric acid, tartaric acid, fumaric acid, levulinic acid, acetic acid, malic acid, formic acid, sorbic acid, benzoic acid, propanoic and pyruvic acid.

Suitably the acid is lactic acid. In other embodiments, the acid is benzoic acid. In other embodiments the acid may be an inorganic acid. In some of these embodiments the acid may be a mineral acid. In some such embodiments, the acid may be at least one of sulphuric acid, hydrochloric acid, boric acid and phosphoric acid. In some embodiments, the acid is levulinic acid.

Inclusion of an acid is particularly preferred in embodiments in which the aerosol-generating composition comprises nicotine. In such embodiments, the presence of an acid may stabilise dissolved species in the slurry from which the aerosol-generating composition is formed. The presence of the acid may reduce or substantially prevent evaporation of nicotine during drying of the slurry, thereby reducing loss of nicotine during manufacturing. The presence of the acid may also improve the flavour of the aerosol when nicotine is present. For example, the perceived harshness of the nicotine may be reduced by the presence of the acid.

In some embodiments, the aerosol-generating material is substantially free from tobacco. By “substantially free from” it is meant that the material comprises less than 1wt%, such as less than 0.5wt% tobacco. In some embodiments, the aerosolgenerating material is free from tobacco. In some embodiments, the aerosolgenerating material does not comprise tobacco fibres. In particular embodiments, the aerosol-generating material does not comprise fibrous material.

In some embodiments, the aerosol-generating composition does not comprise tobacco fibres. In particular embodiments, the aerosol-generating composition does not comprise fibrous material.

Aerosol-generating composition

An aspect provides an aerosol-generating composition comprising an aerosolgenerating material as defined herein.

In some embodiments, the aerosol-generating composition further comprises tobacco material. In these embodiments, the tobacco material does not form part of the aerosol-generating material. That is, it is present in the aerosol-generating composition separately to the aerosol-generating material.

As used herein, the term “tobacco material” refers to any material comprising tobacco or derivatives therefore. The term “tobacco material” may include one or more of tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes. The tobacco material may comprise one or more of ground tobacco, tobacco fibre, cut tobacco, extruded tobacco, tobacco stem, reconstituted tobacco and/or tobacco extract.

The tobacco used to produce tobacco material may be any suitable tobacco, such as single grades or blends, cut rag or whole leaf, including Virginia and/or Burley and/or Oriental. It may also be tobacco particle ‘fines’ or dust, expanded tobacco, stems, expanded stems, and other processed stem materials, such as cut rolled stems. The tobacco material may be a ground tobacco or a reconstituted tobacco material. The reconstituted tobacco material may comprise tobacco fibres, and may be formed by casting, a Fourdrinier-based paper making-type approach with back addition of tobacco extract, or by extrusion.

In some embodiments, the amount of aerosol-former material in the aerosolgenerating composition is from about 5 to about 30 wt% of the aerosol-generating composition on a dry weight basis. For example, in some embodiments the aerosolgenerating composition comprises aerosol-former material in an amount of from about 10 to about 20 wt%, or about 13 to about 17 wt%. In some embodiments, the aerosolgenerating composition comprises aerosol-former material in an amount of about 15 wt%. This amount includes any aerosol-former material present in the aerosolgenerating composition, such as aerosol-former material provided in the aerosolgenerating material and any aerosol-former material loaded on to the tobacco material.

In some embodiments, the tobacco material comprises or consists of lamina tobacco (such as cut rag tobacco), which provides desirable sensory characteristics.

In some embodiments, the tobacco material comprises reconstituted tobacco in an amount less than about 50 wt%, 30 wt%, 10 wt%, 5 wt%, or 1 wt% by dry weight of the tobacco material. In some embodiments, the tobacco material substantially does not comprise reconstituted tobacco.

The tobacco material may be present in any format, but is typically fine-cut (e.g. cut into narrow shreds). Fine-cut tobacco material may advantageously be blended with the aerosol-generating material to provide an aerosol-generating composition which has an even dispersion of tobacco material and aerosol-generating material throughout the aerosol-generating composition.

In some embodiments, the tobacco material comprises one or more of ground tobacco, tobacco fibre, cut tobacco, extruded tobacco, tobacco stem, reconstituted tobacco and/or tobacco extract. It is possible to use a relatively large amount of lamina tobacco in the aerosol-generating composition and still provide an acceptable aerosol when heated by a non-combustible aerosol provision system. Lamina tobacco typically provides superior sensory characteristics. In examples, the tobacco material comprises lamina tobacco in an amount of at least about 50 wt%, 60 wt%, 70 wt%, 80 wt%, 85 wt%, 90 wt%, or 95 wt% of the tobacco material. In particular examples, the tobacco material comprises cut tobacco in an amount of at least about 50 wt%, 60 wt%, 70 wt%, 80 wt%, 85 wt%, 90 wt%, or 95 wt% of the tobacco material.

The tobacco used to produce tobacco material may be any suitable tobacco, such as single grades or blends, cut rag or whole leaf, including Virginia and/or Burley and/or Oriental.

The tobacco material may typically be present in the aerosol-generating composition in an amount of from about 50 to 95 wt%, or about 60 to 95 wt%, or about 70 to 90 wt%, or about 80 to 90 wt% of the aerosol generating composition.

In some embodiments, the aerosol-generating material is present in the aerosol-generating composition in an amount of about 5 to 40 wt%, 5 to 30 wt%, 5 to 25 wt%, or 10 to 25 wt% or 10 to 20 wt%.

In some embodiments, the aerosol-generating composition consists of, or consists essentially of the aerosol-generating material and the tobacco material.

In some embodiments, the tobacco material itself comprises aerosol-former material. Typically, the tobacco material comprises tobacco which is fine-cut, and aerosol-former material is loaded onto the shreds of tobacco. In examples, the tobacco material comprises aerosol-former material in an amount of from about 1 to 10 wt% of the tobacco material, such as about 3 to 6 wt%. The aerosol-former material defined above in relation to the aerosol-generating material are also suitable for use in the tobacco material.

The aerosol-generating material may be present in the aerosol-generating composition in any suitable form. In examples, the aerosol-generating material is present in sheet form. In examples, the aerosol-generating material is present as a shredded sheet (e.g. the aerosol-generating composition comprises shreds of aerosolgenerating material). In examples, the aerosol-generating material is present as a shredded sheet and is blended with tobacco material which is fine-cut and/or shredded, e.g. the aerosol-generating material and tobacco material are in a similar form. Advantageously, providing both the aerosol-generating material and tobacco material as shreds / fine-cut portions allows for an aerosol-generating composition blend which has an even dispersion of aerosol-generating material and tobacco material throughout the aerosol-generating composition.

In examples, the aerosol-generating material has an area density which is from about 90 to 110% of the area density of any tobacco material in the aerosol generating composition. That is, the aerosol-generating material and the tobacco material have similar area densities. Configuring the aerosol-generating material and tobacco material to have similar area densities may allow for better blending of the aerosolgenerating material and tobacco material, typically when provided as shredded sheet. For example, aerosol-generated material in the form of a shredded sheet and cut rag tobacco which have similar area densities can be blended to provide a more homogenous aerosol-generating composition (e.g. better distribution of each component throughout the aerosol-generating composition).

Fine cut tobacco (such as cut rag tobacco) has a cut width, typically represented as CPI (cuts per inch), and refers to the width of a shred of tobacco. In some examples where the tobacco material is fine cut (e.g. where the tobacco material comprises cut rag tobacco) and the aerosol-generating material is a shredded sheet, the cut width of the aerosol-generating material is from about 90 to 110% of the cut width of the cut rag tobacco. That is, the aerosol-generating material and the tobacco material have similar cut widths, or shred widths. Configuring the aerosol-generating material and tobacco material to have similar cut widths allows for better blending of the aerosol-generating material and tobacco material. For example, shredded aerosolgenerating material sheet and cut rag tobacco which have similar cut widths can be blended to provide a more homogenous aerosol-generating composition (e.g. better distribution of each component throughout the aerosol-generating composition). The tobacco material may have a length of 1-4 cm.

Support

The aerosol-generating material may be present on or in a support to form a substrate. The support functions as a support on which the aerosol-generating material layer forms, easing manufacture. The support may provide rigidity to the aerosolgenerating material layer, easing handling. The support may be any suitable material which can be used to support an aerosol-generating material. In some cases, the support may be formed from materials selected from metal foil, paper, carbon paper, greaseproof paper, ceramic, carbon allotropes such as graphite and graphene, plastic, cardboard, wood or combinations thereof. In some cases, the support may comprise or consist of a tobacco material, such as a sheet of reconstituted tobacco. In some cases, the support may be formed from materials selected from metal foil, paper, cardboard, wood or combinations thereof. In some cases, the support comprises paper. In some cases, the support itself may be a laminate structure comprising layers of materials selected from the preceding lists. In some cases, the support may also function as a flavour support. For example, the support may be impregnated with a flavourant or with tobacco extract.

Suitably, the thickness of the support layer may be in the range of about 10pm, 15pm, 17pm, 20pm, 23pm, 25pm, 50pm, 75pm or 0.1mm to about 2.5mm, 2.0mm, 1.5mm, 1.0mm or 0.5mm. The support may comprise more than one layer, and the thickness described herein refers to the aggregate thickness of those layers.

In some cases, the support may be magnetic. This functionality may be used to fasten the support to the assembly in use, or may be used to generate particular aerosol-generating material shapes. In some cases, the aerosol-generating substrate may comprise one or more magnets which can be used to fasten the substrate to an induction heater in use.

In some cases, the support may be substantially or wholly impermeable to gas and/or aerosol. This prevents aerosol or gas passage through the support layer, thereby controlling the flow and ensuring it is delivered to the user. This can also be used to prevent condensation or other deposition of the gas/aerosol in use on, for example, the surface of a heater provided in an aerosol generating assembly. Thus, consumption efficiency and hygiene can be improved in some cases.

In some cases, the surface of the support that abuts the aerosol-generating material may be porous. For example, in one case, the support comprises paper. A porous support such as paper is particularly suitable for the present invention; the porous (e.g. paper) layer abuts the aerosol-generating layer and forms a strong bond. The aerosol-generating material is formed by drying a gel and, without being limited by theory, it is thought that the slurry from which the gel is formed partially impregnates the porous support (e.g. paper) so that when the gel sets and forms cross-links, the support is partially bound into the gel. This provides a strong binding between the gel and the support (and between the dried gel and the support).

Additionally, surface roughness may contribute to the strength of bond between the aerosol-generating material and the support. The paper roughness (for the surface abutting the support) may suitably be in the range of 50-1000 Bekk seconds, suitably 50-150 Bekk seconds, suitably 100 Bekk seconds (measured over an air pressure interval of 50.66-48.00 kPa). (A Bekk smoothness tester is an instrument used to determine the smoothness of a paper surface, in which air at a specified pressure is leaked between a smooth glass surface and a paper sample, and the time (in seconds) for a fixed volume of air to seep between these surfaces is the "Bekk smoothness”.)

Conversely, the surface of the support facing away from the aerosol-generating material may be arranged in contact with the heater, and a smoother surface may provide more efficient heat transfer. Thus, in some cases, the support is disposed so as to have a rougher side abutting the aerosol-generating material and a smoother side facing away from the aerosol-generating material.

In one particular case, the support may be a paper-backed foil; the paper layer abuts the aerosol-generating material layer and the properties discussed in the previous paragraphs are afforded by this abutment. The foil backing is substantially impermeable, providing control of the aerosol flow path. A metal foil backing may also serve to conduct heat to the aerosol-generating material.

In another case, the foil layer of the paper-backed foil abuts the aerosolgenerating material. The foil is substantially impermeable, thereby preventing water provided in the aerosol-generating material to be absorbed into the paper which could weaken its structural integrity.

In some cases, the support is formed from or comprises metal foil, such as aluminium foil. A metallic support may allow for better conduction of thermal energy to the aerosol-generating material. Additionally, or alternatively, a metal foil may function as a susceptor in an induction heating system. In particular embodiments, the support comprises a metal foil layer and a support layer, such as cardboard. In these embodiments, the metal foil layer may have a thickness of less than 20pm, such as from about 1 m to about 10pm, suitably about 5pm. In some cases, the support may have a thickness of between about 0.017mm and about 2.0mm, suitably from about 0.02mm, 0.05mm or 0.1mm to about 1.5mm, 1.0mm, or 0.5mm.

The aerosol-generating material may be made from a gel, and this gel may additionally comprise a solvent, included at 0.1-50wt%. However, the inclusion of a solvent in which the flavour is soluble may reduce the gel stability and the flavour may crystallise out of the gel. As such, in some cases, the gel does not include a solvent in which the flavour is soluble.

The aerosol-generating material may have a density from about 0.02 g/cm³, 0.06 g/cm³, 0.1 g/cm³ or 0.15 g/cm³ to about 0.25 g/cm³, 0.4 g/cm³, 0.6 g/cm³ or 0.7 g/cm³. In exemplary embodiments, the aerosol-generating material has a density from 0.02-0.7 g/cm³, 0.02-0.6 g/cm³, 0.02-0.5 g/cm³ 0.02-0.4 g/cm³ or 0.1 -0.3 g/cm³.

The aerosol-generating material may have a fill value of more than about 380 cm³/100 g, more than about 400 cm³/100 g or more than 420 cm³/100 g.

The fill value may be measured using a densimeter.

In one embodiment, the fill value is measured according to Method A: Approximately 70-80 g of the aerosol-generating material is weighed. The weighed aerosol-generating material is then transferred to the container assembly of a densimeter and the bulk volume measured. The fill value is then calculated according to equation 1.

Fill value = (bulk volume / weight) x 100 (Equation 1)

In some embodiments, there is provided an aerosol-generating material comprising:

(i) one or more foam forming agents;

(ii) filler; and

(iii) aerosol-former material; wherein the aerosol-generating material is a foam; wherein the aerosol-generating material has a density from about 0.02 g/cm³ to about 0.7 g/cm³; and wherein the aerosol-generating material has a fill value of more than about 380 g/cm³. The aerosol-generating material may have a Gurley porosity of about 100 s/100 mL or more, 125 s/100 mL or more or 150 s/100 mL or more.

The Gurley porosity may be measured using a Gurley Densometer.

In one embodiment, the Gurley porosity is measured according to Method B: The aerosol-generating material is placed between the clamping plates in a Gurley Densometer. The inner cylinder is then lowered and the time taken for 100 cc of air to flow through the material is measured.

(i) one or more foam forming agents;

(ii) filler; and

(iii) aerosol-former material; wherein the aerosol-generating material is a foam; wherein the aerosol-generating material has a density from about 0.02 g/cm³ to about 0.7 g/cm³; and wherein the aerosol-generating material has a Gurley porosity of about 100 s/100 mL or more.

Consumable

An aspect of the present invention relates to an article (also referred to herein as a consumable). A consumable is an article, part or all of which is intended to be consumed during use by a user. A consumable may comprise or consist of aerosolgenerating composition. A consumable may comprise one or more other elements, such as a filter or an aerosol modifying substance. A consumable may comprise a heating element that emits heat to cause the aerosol-generating composition to generate aerosol in use. The heating element may, for example, comprise combustible material, or may comprise a susceptor that is heatable by penetration with a varying magnetic field.

A susceptor is material that is heatable by penetration with a varying magnetic field, such as an alternating magnetic field. The heating material may be an electrically- conductive material, so that penetration thereof with a varying magnetic field causes induction heating of the heating material. The heating material may be magnetic material, so that penetration thereof with a varying magnetic field causes magnetic hysteresis heating of the heating material. The heating material may be both electrically-conductive and magnetic, so that the heating material is heatable by both heating mechanisms.

Induction heating is a process in which an electrically-conductive object is heated by penetrating the object with a varying magnetic field. The process is described by Faraday's law of induction and Ohm's law. An induction heater may comprise an electromagnet and a device for passing a varying electrical current, such as an alternating current, through the electromagnet. When the electromagnet and the object to be heated are suitably relatively positioned so that the resultant varying magnetic field produced by the electromagnet penetrates the object, one or more eddy currents are generated inside the object. The object has a resistance to the flow of electrical currents. Therefore, when such eddy currents are generated in the object, their flow against the electrical resistance of the object causes the object to be heated. This process is called Joule, ohmic, or resistive heating.

In some embodiments, the susceptor is in the form of a closed circuit. It has been found that, when the susceptor is in the form of a closed circuit, magnetic coupling between the susceptor and the electromagnet in use is enhanced, which results in greater or improved Joule heating.

Magnetic hysteresis heating is a process in which an object made of a magnetic material is heated by penetrating the object with a varying magnetic field. A magnetic material can be considered to comprise many atomic-scale magnets, or magnetic dipoles. When a magnetic field penetrates such material, the magnetic dipoles align with the magnetic field. Therefore, when a varying magnetic field, such as an alternating magnetic field, for example as produced by an electromagnet, penetrates the magnetic material, the orientation of the magnetic dipoles changes with the varying applied magnetic field. Such magnetic dipole reorientation causes heat to be generated in the magnetic material.

When an object is both electrically-conductive and magnetic, penetrating the object with a varying magnetic field can cause both Joule heating and magnetic hysteresis heating in the object. Moreover, the use of magnetic material can strengthen the magnetic field, which can intensify the Joule heating. In each of the above processes, as heat is generated inside the object itself, rather than by an external heat source by heat conduction, a rapid temperature rise in the object and more uniform heat distribution can be achieved, particularly through selection of suitable object material and geometry, and suitable varying magnetic field magnitude and orientation relative to the object. Moreover, as induction heating and magnetic hysteresis heating do not require a physical connection to be provided between the source of the varying magnetic field and the object, design freedom and control over the heating profile may be greater, and cost may be lower.

Articles of the present invention may be provided in any suitable shape. In some examples, the article is provided as a rod (e.g. substantially cylindrical). An article provided as a rod may include the aerosol-generating composition as a shredded sheet, optionally blended with cut tobacco. Alternatively, or additionally, the article provided as a rod may include the aerosol-generating composition as a sheet, such as a sheet circumscribing a rod of aerosol-generating material (e.g. tobacco, or a combination of tobacco and an aerosol-generating material such as that described herein). In some embodiments, the article comprises a layer portion of aerosolgenerating composition disposed on a carrier. In examples, the article may have at least one substantially planar (flat) surface.

The aerosol-generating material is a foam. In some cases, the aerosolgenerating material is porous.

The aerosol-generating material may be continuous. For example, the foam may comprise or be a continuous sheet of material. The sheet may be cut into strips, such as from about 20 to 30 cuts per inch and used as a consumable or a cigarette filler. The sheet may also be shredded to form a shredded sheet and gathered into strands or bundles which are used as a consumable or cigarette. The sheet may be in the form of a wrapper, it may be gathered to form a gathered sheet.

In some embodiments, the aerosol-generating material is shredded and blended with other substrates. In one case, the aerosol-generating material is shredded and blended with another shredded aerosol-generating material. In some cases the aerosol-generating material is shredded and blended with tobacco material.

The thickness values stipulated herein are mean values for the thickness in question. In some cases, the thickness may vary by no more than 25%, 20%, 15%, 10%, 5% or 1%. The “thickness” of the aerosol-generating material describes the shortest distance between a first surface and a second surface. In embodiments where the aerosol-generating material is in the form of a sheet, the thickness of the aerosolgenerating material is the shortest distance between a first planar surface of the sheet and a second planar surface of the sheet which opposes the first planar surface of the sheet. In some cases, the aerosol-generating composition may have a thickness of about 0.015mm to about 10mm. Suitably, the thickness may be in the range of about 0.05mm, 0.1mm or 0.15mm to about 5mm, 3mm, 2mm, 1mm, 0.5mm or 0.3mm. The aerosol-generating material may comprise more than one layer, and the thickness described herein refers to the aggregate thickness of those layers.

In some cases, the aerosol-generating material (i.e. the foam) may have a thickness of about 0.015mm to about 10mm. Suitably, the thickness may be in the range of about 0.05mm, 0.1mm or 0.15mm to about 5mm, 3mm, 2mm, 1mm, 0.5mm or 0.3mm. The aerosol-generating material may comprise more than one layer, and the thickness described herein refers to the aggregate thickness of those layers.

The delivery system described herein can be implemented as a combustible aerosol provision system or a non-combustible aerosol provision system.

Combustible Aerosol Provision System

An aspect of the invention provides a combustible aerosol provision system where a constituent aerosol-generating material of the aerosol provision system (or component thereof) is combusted or burned during use in order to facilitate delivery of at least one substance to a user.

In some embodiments, the delivery system is a combustible aerosol provision system, such as a system selected from the group consisting of a cigarette, a cigarillo and a cigar.

Non-combustible aerosol provision device

An aspect of the invention provides non-combustible aerosol provision system comprising an article according as described herein and non-combustible aerosol provision device comprising a heater which is configured to heat not burn the aerosolgenerating article. A non-combustible aerosol provision system may also be referred to as an aerosol generating assembly. A non-combustible aerosol provision device may be referred to as an aerosol generating apparatus.

In some cases, in use, the heater may heat, without burning, the aerosolgenerating material to a temperature equal to or less than 350 °C, such as between 120°C and 350 °C. In some cases, the heater may heat, without burning, the aerosolgenerating composition to between 140 °C and 250 °C in use, or between 220 °C and 280 °C. In some cases in use, substantially all of the aerosol-generating material is less than about 4mm, 3mm, 2mm or 1mm from the heater. In some cases, the material is disposed between about 0.010mm and 2.0mm from the heater, suitably between about 0.02mm and 1 .0mm, suitably 0.1 mm to 0.5mm. These minimum distances may, in some cases, reflect the thickness of a support that supports the aerosol-generating material. In some cases, a surface of the aerosol-generating material may directly abut the heater.

The heater is configured to heat not burn the aerosol-generating article, and thus the aerosol-generating composition. The heater may be, in some cases, a thin film, electrically resistive heater. In other cases, the heater may comprise an induction heater or the like. The heater may be a combustible heat source or a chemical heat source which undergoes an exothermic reaction to produce heat in use. The aerosol generating assembly may comprise a plurality of heaters. The heater(s) may be powered by a battery.

The aerosol-generating article may additionally comprise a cooling element and/or a filter. The cooling element, if present, may act or function to cool gaseous or aerosol components. In some cases, it may act to cool gaseous components such that they condense to form an aerosol. It may also act to space the very hot parts of the non-combustible aerosol provision device from the user. The filter, if present, may comprise any suitable filter known in the art such as a cellulose acetate plug.

In some cases, the aerosol generating assembly may be a heat-not-burn device. That is, it may contain a solid tobacco-containing material (and no liquid aerosol-generating material). In some cases, the aerosol-generating material may comprise the tobacco material. A heat-not-burn device is disclosed in WO 2015/062983 A2, which is incorporated by reference in its entirety. In some cases, the aerosol generating assembly may be an electronic tobacco hybrid device. That is, it may contain a solid aerosol-generating composition and a liquid aerosol-generating material. In some cases, the aerosol-generating material may comprise nicotine. In some cases, the aerosol-generating material may comprise a tobacco material. In some cases, the aerosol-generating material may comprise a tobacco material and a separate nicotine source. The separate aerosol-generating compositions may be heated by separate heaters, the same heater or, in one case, a downstream aerosol-generating material may be heated by a hot aerosol which is generated from the upstream aerosol-generating composition. An electronic tobacco hybrid device is disclosed in WO 2016/135331 A1 , which is incorporated by reference in its entirety.

The aerosol-generating article (which may be referred to herein as an article, a cartridge or a consumable) may be adapted for use in a THP, an electronic tobacco hybrid device or another aerosol generating device. In some cases, the article may additionally comprise a filter and/or cooling element (which have been described above). In some cases, the aerosol-generating article may be circumscribed by a wrapping material such as paper.

The aerosol-generating article may additionally comprise ventilation apertures. These may be provided in the sidewall of the article. In some cases, the ventilation apertures may be provided in the filter and/or cooling element. These apertures may allow cool air to be drawn into the article during use, which can mix with the heated volatilised components thereby cooling the aerosol.

The ventilation enhances the generation of visible heated volatilised components from the article when it is heated in use. The heated volatilised components are made visible by the process of cooling the heated volatilised components such that supersaturation of the heated volatilised components occurs. The heated volatilised components then undergo droplet formation, otherwise known as nucleation, and eventually the size of the aerosol particles of the heated volatilised components increases by further condensation of the heated volatilised components and by coagulation of newly formed droplets from the heated volatilised components.

In some cases, the ratio of the cool air to the sum of the heated volatilised components and the cool air, known as the ventilation ratio, is at least 15%. A ventilation ratio of 15% enables the heated volatilised components to be made visible by the method described above. The visibility of the heated volatilised components enables the user to identify that the volatilised components have been generated and adds to the sensory experience of the smoking experience.

In another example, the ventilation ratio is between 50% and 85% to provide additional cooling to the heated volatilised components. In some cases, the ventilation ratio may be at least 60% or 65%.

In some cases, the aerosol-generating composition may be included in the article/assembly in sheet form. In some cases, the aerosol-generating composition may be included as a planar sheet. In some cases, the aerosol-generating composition may be included as a planar sheet, as a bunched or gathered sheet, as a crimped sheet, or as a rolled sheet (i.e. in the form of a tube). In some such cases, the aerosolgenerating material of these embodiments may be included in an aerosol-generating article/assembly as a sheet, such as a sheet circumscribing a rod of aerosol-generating material (e.g. tobacco). In some other cases, the aerosol-generating composition may be formed as a sheet and then shredded and incorporated into the article. In some cases, the shredded sheet may be mixed with cut rag tobacco and incorporated into the article.

In some cases, the first and second aerosol-generating materials described herein may both be formed as a sheet and then shredded and mixed together to form an aerosol-generating composition. Said composition may then be incorporated into the article. In some cases, the shredded sheets may also be mixed with cut rag tobacco and incorporated into the article.

In some embodiments, the aerosol-generating material is formed as a foam on a support. The aerosol-generating foam may be a continuous foam or a discontinuous foam, such as an arrangement of discrete portions of foam on a support.

Referring to Figures 1 and 2, there are shown a partially cut-away section view and a perspective view of an example of an aerosol-generating article 101. The article 101 is adapted for use with a device having a power source and a heater. The article 101 of this embodiment is particularly suitable for use with the device 1 shown in Figures 5 to 7, described below. In use, the article 101 may be removably inserted into the device shown in Figure 5 at an insertion point 20 of the device 1 . The article 101 of one example is in the form of a substantially cylindrical rod that includes a body of aerosol-generating composition 103 and a filter assembly 105 in the form of a rod. The aerosol-generating composition comprises the aerosolgenerating material described herein. In some embodiments, it may be included in sheet form. In some embodiments it may be included in the form of a shredded sheet. In some embodiments, the aerosol-generating composition described herein may be incorporated in sheet form and in shredded form.

The filter assembly 105 includes three segments, a cooling segment 107, a filter segment 109 and a mouth end segment 111. The article 101 has a first end 113, also known as a mouth end or a proximal end and a second end 115, also known as a distal end. The body of aerosol-generating composition 103 is located towards the distal end 115 of the article 101. In one example, the cooling segment 107 is located adjacent the body of aerosol-generating composition 103 between the body of aerosolgenerating composition 103 and the filter segment 109, such that the cooling segment 107 is in an abutting relationship with the aerosol-generating composition 103 and the filter segment 103. In other examples, there may be a separation between the body of aerosol-generating composition 103 and the cooling segment 107 and between the body of aerosol-generating composition 103 and the filter segment 109. The filter segment 109 is located in between the cooling segment 107 and the mouth end segment 111. The mouth end segment 111 is located towards the proximal end 113 of the article 101 , adjacent the filter segment 109. In one example, the filter segment 109 is in an abutting relationship with the mouth end segment 111. In one embodiment, the total length of the filter assembly 105 is between 37mm and 45mm, more preferably, the total length of the filter assembly 105 is 41mm.

In one example, the rod of aerosol-generating composition 103 is between 34mm and 50mm in length, suitably between 38mm and 46mm in length, suitably 42mm in length.

In one example, the total length of the article 101 is between 71 mm and 95mm, suitably between 79mm and 87mm, suitably 83mm.

An axial end of the body of aerosol-generating composition 103 is visible at the distal end 115 of the article 101. However, in other embodiments, the distal end 115 of the article 101 may comprise an end member (not shown) covering the axial end of the body of aerosol-generating composition 103. The body of aerosol-generating composition 103 is joined to the filter assembly 105 by annular tipping paper (not shown), which is located substantially around the circumference of the filter assembly 105 to surround the filter assembly 105 and extends partially along the length of the body of aerosol-generating composition 103. In one example, the tipping paper is made of 58GSM standard tipping base paper. In one example the tipping paper has a length of between 42mm and 50mm, suitably of 46mm.

In one example, the cooling segment 107 is an annular tube and is located around and defines an air gap within the cooling segment. The air gap provides a chamber for heated volatilised components generated from the body of aerosolgenerating composition 103 to flow. The cooling segment 107 is hollow to provide a chamber for aerosol accumulation yet rigid enough to withstand axial compressive forces and bending moments that might arise during manufacture and whilst the article 101 is in use during insertion into the device 1. In one example, the thickness of the wall of the cooling segment 107 is approximately 0.29mm.

The cooling segment 107 provides a physical displacement between the aerosol-generating composition 103 and the filter segment 109. The physical displacement provided by the cooling segment 107 will provide a thermal gradient across the length of the cooling segment 107. In one example the cooling segment 107 is configured to provide a temperature differential of at least 40 degrees Celsius between a heated volatilised component entering a first end of the cooling segment 107 and a heated volatilised component exiting a second end of the cooling segment 107. In one example the cooling segment 107 is configured to provide a temperature differential of at least 60 degrees Celsius between a heated volatilised component entering a first end of the cooling segment 107 and a heated volatilised component exiting a second end of the cooling segment 107. This temperature differential across the length of the cooling element 107 protects the temperature sensitive filter segment 109 from the high temperatures of the aerosol-generating composition 103 when it is heated by the device 1 . If the physical displacement was not provided between the filter segment 109 and the body of aerosol-generating composition 103 and the heating elements of the device 1 , then the temperature sensitive filter segment may 109 become damaged in use, so it would not perform its required functions as effectively. In one example the length of the cooling segment 107 is at least 15mm. In one example, the length of the cooling segment 107 is between 20mm and 30mm, more particularly 23mm to 27mm, more particularly 25mm to 27mm, suitably 25mm.

The cooling segment 107 is made of paper, which means that it is comprised of a material that does not generate compounds of concern, for example, toxic compounds when in use adjacent to the heater of the device 1. In one example, the cooling segment 107 is manufactured from a spirally wound paper tube which provides a hollow internal chamber yet maintains mechanical rigidity. Spirally wound paper tubes are able to meet the tight dimensional accuracy requirements of high-speed manufacturing processes with respect to tube length, outer diameter, roundness and straightness.

In another example, the cooling segment 107 is a recess created from stiff plug wrap or tipping paper. The stiff plug wrap or tipping paper is manufactured to have a rigidity that is sufficient to withstand the axial compressive forces and bending moments that might arise during manufacture and whilst the article 101 is in use during insertion into the device 1.

The filter segment 109 may be formed of any filter material sufficient to remove one or more volatilised compounds from heated volatilised components from the aerosol-generating material. In one example the filter segment 109 is made of a monoacetate material, such as cellulose acetate. The filter segment 109 provides cooling and irritation-reduction from the heated volatilised components without depleting the quantity of the heated volatilised components to an unsatisfactory level for a user.

In some embodiments, a capsule (not illustrated) may be provided in filter segment 109. It may be disposed substantially centrally in the filter segment 109, both across the filter segment 109 diameter and along the filter segment 109 length. In other cases, it may be offset in one or more dimension. The capsule may in some cases, where present, contain a volatile component such as a flavourant or aerosol-former material.

The density of the cellulose acetate tow material of the filter segment 109 controls the pressure drop across the filter segment 109, which in turn controls the draw resistance of the article 101. Therefore the selection of the material of the filter segment 109 is important in controlling the resistance to draw of the article 101. In addition, the filter segment performs a filtration function in the article 101.

In one example, the filter segment 109 is made of a 8Y15 grade of filter tow material, which provides a filtration effect on the heated volatilised material, whilst also reducing the size of condensed aerosol droplets which result from the heated volatilised material.

The presence of the filter segment 109 provides an insulating effect by providing further cooling to the heated volatilised components that exit the cooling segment 107. This further cooling effect reduces the contact temperature of the user’s lips on the surface of the filter segment 109.

In one example, the filter segment 109 is between 6mm to 10mm in length, suitably 8mm.

The mouth end segment 111 is an annular tube and is located around and defines an air gap within the mouth end segment 111. The air gap provides a chamber for heated volatilised components that flow from the filter segment 109. The mouth end segment 111 is hollow to provide a chamber for aerosol accumulation yet rigid enough to withstand axial compressive forces and bending moments that might arise during manufacture and whilst the article is in use during insertion into the device 1. In one example, the thickness of the wall of the mouth end segment 111 is approximately 0.29mm. In one example, the length of the mouth end segment 111 is between 6mm to 10mm, suitably 8mm.

The mouth end segment 111 may be manufactured from a spirally wound paper tube which provides a hollow internal chamber yet maintains critical mechanical rigidity. Spirally wound paper tubes are able to meet the tight dimensional accuracy requirements of high-speed manufacturing processes with respect to tube length, outer diameter, roundness and straightness.

The mouth end segment 111 provides the function of preventing any liquid condensate that accumulates at the exit of the filter segment 109 from coming into direct contact with a user.

It should be appreciated that, in one example, the mouth end segment 111 and the cooling segment 107 may be formed of a single tube and the filter segment 109 is located within that tube separating the mouth end segment 111 and the cooling segment 107.

Referring to Figures 3 and 4, there are shown a partially cut-away section and perspective views of an example of an article 301. The reference signs shown in Figures 3 and 4 are equivalent to the reference signs shown in Figures 1 and 2, but with an increment of 200.

In the example of the article 301 shown in Figures 3 and 4, a ventilation region 317 is provided in the article 301 to enable air to flow into the interior of the article 301 from the exterior of the article 301. In one example the ventilation region 317 takes the form of one or more ventilation holes 317 formed through the outer layer of the article 301. The ventilation holes may be located in the cooling segment 307 to aid with the cooling of the article 301. In one example, the ventilation region 317 comprises one or more rows of holes, and preferably, each row of holes is arranged circumferentially around the article 301 in a cross-section that is substantially perpendicular to a longitudinal axis of the article 301 .

In one example, there are between one to four rows of ventilation holes to provide ventilation for the article 301. Each row of ventilation holes may have between 12 to 36 ventilation holes 317. The ventilation holes 317 may, for example, be between 100 to 500pm in diameter. In one example, an axial separation between rows of ventilation holes 317 is between 0.25mm and 0.75mm, suitably 0.5mm.

In one example, the ventilation holes 317 are of uniform size. In another example, the ventilation holes 317 vary in size. The ventilation holes can be made using any suitable technique, for example, one or more of the following techniques: laser technology, mechanical perforation of the cooling segment 307 or pre-perforation of the cooling segment 307 before it is formed into the article 301. The ventilation holes 317 are positioned so as to provide effective cooling to the article 301 .

In one example, the rows of ventilation holes 317 are located at least 11mm from the proximal end 313 of the article, suitably between 17mm and 20mm from the proximal end 313 of the article 301. The location of the ventilation holes 317 is positioned such that user does not block the ventilation holes 317 when the article 301 is in use. Providing the rows of ventilation holes between 17mm and 20mm from the proximal end 313 of the article 301 enables the ventilation holes 317 to be located outside of the device 1 , when the article 301 is fully inserted in the device 1 , as can be seen in Figures 6 and 7. By locating the ventilation holes outside of the device, nonheated air is able to enter the article 301 through the ventilation holes from outside the device 1 to aid with the cooling of the article 301.

The length of the cooling segment 307 is such that the cooling segment 307 will be partially inserted into the device 1 , when the article 301 is fully inserted into the device 1 . The length of the cooling segment 307 provides a first function of providing a physical gap between the heater arrangement of the device 1 and the heat sensitive filter arrangement 309, and a second function of enabling the ventilation holes 317 to be located in the cooling segment, whilst also being located outside of the device 1 , when the article 301 is fully inserted into the device 1. As can be seen from Figures 6 and 7, the majority of the cooling element 307 is located within the device 1. However, there is a portion of the cooling element 307 that extends out of the device 1. It is in this portion of the cooling element 307 that extends out of the device 1 in which the ventilation holes 317 are located.

Referring now to Figures 5 to 7 in more detail, there is shown an example of a device 1 arranged to heat aerosol-generating composition to volatilise at least one component of said aerosol-generating composition, typically to form an aerosol which can be inhaled. The device 1 is a heating device which releases compounds by heating, but not burning, the aerosol-generating composition.

A first end 3 is sometimes referred to herein as the mouth or proximal end 3 of the device 1 and a second end 5 is sometimes referred to herein as the distal end 5 of the device 1. The device 1 has an on/off button 7 to allow the device 1 as a whole to be switched on and off as desired by a user.

The device 1 comprises a housing 9 for locating and protecting various internal components of the device 1. In the example shown, the housing 9 comprises a unibody sleeve 11 that encompasses the perimeter of the device 1 , capped with a top panel 17 which defines generally the ‘top’ of the device 1 and a bottom panel 19 which defines generally the ‘bottom’ of the device 1. In another example the housing comprises a front panel, a rear panel and a pair of opposite side panels in addition to the top panel 17 and the bottom panel 19. The top panel 17 and/or the bottom panel 19 may be removably fixed to the uni-body sleeve 11 , to permit easy access to the interior of the device 1 , or may be “permanently” fixed to the uni-body sleeve 11 , for example to deter a user from accessing the interior of the device 1. In an example, the panels 17 and 19 are made of a plastics material, including for example glass-filled nylon formed by injection moulding, and the uni-body sleeve 11 is made of aluminium, though other materials and other manufacturing processes may be used.

The top panel 17 of the device 1 has an opening 20 at the mouth end 3 of the device 1 through which, in use, the article 101 , 301 including the aerosol-generating composition may be inserted into the device 1 and removed from the device 1 by a user.

The housing 9 has located or fixed therein a heater arrangement 23, control circuitry 25 and a power source 27. In this example, the heater arrangement 23, the control circuitry 25 and the power source 27 are laterally adjacent (that is, adjacent when viewed from an end), with the control circuitry 25 being located generally between the heater arrangement 23 and the power source 27, though other locations are possible.

The control circuitry 25 may include a controller, such as a microprocessor arrangement, configured and arranged to control the heating of the aerosol-generating composition in the article 101 , 301 as discussed further below.

The power source 27 may be for example a battery, which may be a rechargeable battery or a non-rechargeable battery. Examples of suitable batteries include for example a lithium-ion battery, a nickel battery (such as a nickel-cadmium battery), an alkaline battery and/ or the like. The battery 27 is electrically coupled to the heater arrangement 23 to supply electrical power when required and under control of the control circuitry 25 to heat the aerosol-generating composition in the article (as discussed, to volatilise the aerosol-generating material without causing the aerosolgenerating composition to burn).

An advantage of locating the power source 27 laterally adjacent to the heater arrangement 23 is that a physically large power source 25 may be used without causing the device 1 as a whole to be unduly lengthy. As will be understood, in general a physically large power source 25 has a higher capacity (that is, the total electrical energy that can be supplied, often measured in Amp-hours or the like) and thus the battery life for the device 1 can be longer.

In one example, the heater arrangement 23 is generally in the form of a hollow cylindrical tube, having a hollow interior heating chamber into which the article 101 , 301 comprising the aerosol-generating material is inserted for heating in use. Different arrangements for the heater arrangement 23 are possible. For example, the heater arrangement 23 may comprise a single heating element or may be formed of plural heating elements aligned along the longitudinal axis of the heater arrangement 23. The or each heating element may be annular or tubular, or at least part-annular or parttubular around its circumference. In an example, the or each heating element may be a thin film heater. In another example, the or each heating element may be made of a ceramics material. Examples of suitable ceramics materials include alumina and aluminium nitride and silicon nitride ceramics, which may be laminated and sintered. Other heating arrangements are possible, including for example inductive heating, infrared heater elements, which heat by emitting infrared radiation, or resistive heating elements formed by for example a resistive electrical winding.

In one particular example, the heater arrangement 23 is supported by a stainless steel support tube and comprises a polyimide heating element. The heater arrangement 23 is dimensioned so that substantially the whole of the body of aerosolgenerating composition 103, 303 of the article 101 , 301 is inserted into the heater arrangement 23 when the article 101 , 301 is inserted into the device 1.

The or each heating element may be arranged so that selected zones of the aerosol-generating material can be independently heated, for example in turn (over time, as discussed above) or together (simultaneously) as desired.

The heater arrangement 23 in this example is surrounded along at least part of its length by a thermal insulator 31 . The insulator 31 helps to reduce heat passing from the heater arrangement 23 to the exterior of the device 1 . This helps to keep down the power requirements for the heater arrangement 23 as it reduces heat losses generally. The insulator 31 also helps to keep the exterior of the device 1 cool during operation of the heater arrangement 23. In one example, the insulator 31 may be a double-walled sleeve which provides a low pressure region between the two walls of the sleeve. That is, the insulator 31 may be for example a “vacuum” tube, i.e. a tube that has been at least partially evacuated so as to minimise heat transfer by conduction and/or convection. Other arrangements for the insulator 31 are possible, including using heat insulating materials, including for example a suitable foam-type material, in addition to or instead of a double-walled sleeve.

The housing 9 may further comprises various internal support structures 37 for supporting all internal components, as well as the heating arrangement 23.

The device 1 further comprises a collar 33 which extends around and projects from the opening 20 into the interior of the housing 9 and a generally tubular chamber 35 which is located between the collar 33 and one end of the vacuum sleeve 31 . The chamber 35 further comprises a cooling structure 35f, which in this example, comprises a plurality of cooling fins 35f spaced apart along the outer surface of the chamber 35, and each arranged circumferentially around outer surface of the chamber 35. There is an air gap 36 between the hollow chamber 35 and the article 101 , 301 when it is inserted in the device 1 over at least part of the length of the hollow chamber 35. The air gap 36 is around all of the circumference of the article 101 , 301 over at least part of the cooling segment 307.

The collar 33 comprises a plurality of ridges 60 arranged circumferentially around the periphery of the opening 20 and which project into the opening 20. The ridges 60 take up space within the opening 20 such that the open span of the opening 20 at the locations of the ridges 60 is less than the open span of the opening 20 at the locations without the ridges 60. The ridges 60 are configured to engage with an article 101 , 301 inserted into the device to assist in securing it within the device 1. Open spaces (not shown in the Figures) defined by adjacent pairs of ridges 60 and the article 101 , 301 form ventilation paths around the exterior of the article 101 , 301. These ventilation paths allow hot vapours that have escaped from the article 101 , 301 to exit the device 1 and allow cooling air to flow into the device 1 around the article 101 , 301 in the air gap 36.

In operation, the article 101 , 301 is removably inserted into an insertion point 20 of the device 1 , as shown in Figures 5 to 7. Referring particularly to Figure 6, in one example, the body of aerosol-generating composition 103, 303, which is located towards the distal end 115, 315 of the article 101 , 301 , is entirely received within the heater arrangement 23 of the device 1. The proximal end 113, 313 of the article 101, 301 extends from the device 1 and acts as a mouthpiece assembly for a user. In operation, the heater arrangement 23 will heat the article 101 , 301 to volatilise at least one component of the aerosol-generating composition from the body of aerosol-generating composition 103, 303.

The primary flow path for the heated volatilised components from the body of aerosol-generating composition 103, 303 is axially through the article 101 , 301 , through the chamber inside the cooling segment 107, 307, through the filter segment 109, 309, through the mouth end segment 111 , 313 to the user. In one example, the temperature of the heated volatilised components that are generated from the body of aerosol-generating composition is between 60°C and 250°C, which may be above the acceptable inhalation temperature for a user. As the heated volatilised component travels through the cooling segment 107, 307, it will cool and some volatilised components will condense on the inner surface of the cooling segment 107, 307.

In the examples of the article 301 shown in Figures 3 and 4, cool air will be able to enter the cooling segment 307 via the ventilation holes 317 formed in the cooling segment 307. This cool air will mix with the heated volatilised components to provide additional cooling to the heated volatilised components.

Method of manufacture

Another aspect of the invention provides a method of making an aerosol-generating composition as described herein.

The method of forming the aerosol-generating material may comprise:

(a) providing a slurry comprising:

(i) one or more foam forming agents;

(ii) filler;

(iii) aerosol-former material; and

(iv) solvent;

(b) aerating the slurry;

(c) forming a layer of the aerated slurry;

(d) drying the slurry to form the aerosol-generating material.

As discussed above, the aerosol-generating material formed from this process is a foam. Step (b) of aerating the slurry may comprise mixing the slurry under high shear conditions.

Step (c) of forming a layer of the slurry may comprise spraying, casting or extruding the slurry, for example. In some cases, the slurry layer is formed by electrospraying the slurry. In some cases, the slurry layer is formed by casting the slurry.

In some cases, (c) and (d) may, at least partially, occur simultaneously (for example, during electrospraying). In some cases, (c) and (d) may occur sequentially.

In some cases, the slurry is applied to a support. The layer of aerated slurry may be formed on a support.

The drying (d) may, in some cases, remove from about 50wt%, 60wt%, 70wt%, 80wt% or 90wt% to about 80wt%, 90wt% or 95wt% (WWB) of water in the slurry.

The drying (d) may, in some cases, may reduce the cast material thickness by at least 80%, suitably 85% or 87%. For instance, the slurry may be cast at a thickness of 2mm, and the resulting dried aerosol-generating material may have a thickness of 0.2mm.

During step (d) the slurry may be heated to remove at least about 60 wt%, 70 wt%, 80 wt%, 85 wt% or 90 wt% of the solvent.

In some embodiments, gas is bubbled through the slurry before step (d).

In some cases, step (a) of providing the slurry comprises mixing the slurry under high shear conditions, such that step (b) is part of step (a). In such an embodiment the method may comprise:

(a) providing a slurry and mixing the slurry under high shear conditions to form an aerated slurry, the slurry comprising:

(i) one or more foam forming agents;

(ii) filler;

(iii) aerosol-former material; and

(iv) solvent;

(b) forming a layer of the aerated slurry; and

(c) drying the slurry to form the aerosol-generating material. The step of aerating the slurry may occur after a layer of the slurry is formed. In such an embodiment the method may comprise:

(a) providing a slurry comprising:

(i) one or more foam forming agents;

(ii) filler;

(iii) aerosol-former material; and

(iv) solvent;

(b) forming a layer of the slurry;

(c) aerating the slurry; and

(d) drying the slurry to form the aerosol-generating material.

In some cases, the step of aerating the slurry may comprise bubbling gas through the slurry.

The slurry itself may also form part of the invention. In some cases, the slurry solvent may consist essentially of or consist of water. In some cases, the slurry may comprise from about 50wt%, 60wt%, 70wt%, 80wt% or 90wt% of solvent (WWB).

In cases where the solvent consists of water, the dry weight content of the slurry may match the dry weight content of the aerosol-generating material. Thus, the discussion herein relating to the solid composition is explicitly disclosed in combination with the slurry aspect of the invention.

The method of forming the aerosol-generating material may comprise:

(a) providing a slurry comprising:

(i) one or more foam forming agents;

(ii) filler;

(iii) an effervescent agent;

(iv) aerosol-former material; and

(v) solvent;

(b) forming a layer of the slurry;

(c) drying the slurry to form the aerosol-generating material.

Step (b) of forming a layer of the slurry may comprise spraying, casting or extruding the slurry, for example. In some cases, the slurry layer is formed by electrospraying the slurry. In some cases, the slurry layer is formed by casting the slurry. In some cases, (b) and (c) may, at least partially, occur simultaneously (for example, during electrospraying). In some cases, (b) and (c) may occur sequentially.

In some cases, the slurry is applied to a support. The layer of the slurry may be formed on a support.

The drying (c) may, in some cases, remove from about 50wt%, 60wt%, 70wt%, 80wt% or 90wt% to about 80wt%, 90wt% or 95wt% (WWB) of water in the slurry.

The drying (c) may, in some cases, may reduce the cast material thickness by at least 80%, suitably 85% or 87%. For instance, the slurry may be cast at a thickness of 2mm, and the resulting dried aerosol-generating material may have a thickness of 0.2mm.

During step (c) the slurry may be heated to remove at least about 60 wt%, 70 wt%, 80 wt%, 85 wt% or 90 wt% of the solvent.

In some embodiments, the slurry is further aerated before step (c). For example, in some embodiments, gas is bubbled through the slurry before step (c).

According to an aspect of the present invention there is provided a method of generating an aerosol using a non-combustible aerosol provision system as described herein. In some embodiments, the method comprises heating the aerosol-generating material to a temperature of less than or equal to 350 °C. In some embodiments, the method comprises heating the aerosol-generating material to a temperature of from about 220 °C to about 280 °C. In some embodiments, the method comprises heating at least a portion of the aerosol-generating material to a temperature of from about 220 °C to about 280 °C over a session of use. “Session of use” as used herein refers to a single period of use of the noncombustible aerosol provision system by a user. The session of use begins at the point at which power is first supplied to at least one heating unit present in the heating assembly. The device will be ready for use after a period of time has elapsed from the start of the session of use. The session of use ends at the point at which no power is supplied to any of the heating elements in the aerosol-generating device. The end of the session of use may coincide with the point at which the smoking article is depleted (the point at which the total particulate matter yield (mg) in each puff would be deemed unacceptably low by a user). The session will have a duration of a plurality of puffs. Said session may have a duration less than 7 minutes, or 6 minutes, or 5 minutes, or 4 minutes and 30 seconds, or 4 minutes, or 3 minutes and 30 seconds. In some embodiments, the session of use may have a duration of from 2 to 5 minutes, or from 3 to 4.5 minutes, or 3.5 to 4.5 minutes, or suitably 4 minutes. A session may be initiated by the user actuating a button or switch on the device, causing at least one heating element to begin rising in temperature.

Example Embodiments

1. An aerosol-generating material or slurry as defined in the Summary of Disclosure.

2. The aerosol-generating material or slurry of Embodiment 1 , comprising about 5-35 wt% foam forming agent.

3. The aerosol-generating material or slurry of Embodiment 2, comprising about 5-25 wt% foam forming agent.

4. The aerosol-generating material or slurry of Embodiment 3, comprising about 5-20 wt% foam forming agent.

5. The aerosol-generating material or slurry of Embodiment 2, comprising about 10-35 wt% foam forming agent.

6. The aerosol-generating material or slurry of Embodiment 5, comprising about 10-25 wt% foam forming agent.

7. The aerosol-generating material or slurry of Embodiment 6, comprising about 10-20 wt% foam forming agent. 8. The aerosol-generating material or slurry of any preceding embodiment, wherein the foam forming agent comprises hydroxypropyl methyl cellulose (HPMC), guar gum, pectin, modified starch (e.g. hydroxylated starch), maltodextrin and mixtures thereof.

9. The aerosol-generating material or slurry of Embodiment 8, wherein the foam forming agent comprises (or is) HPMC.

10. The aerosol-generating material or slurry of any preceding embodiment, comprising about 10-80 wt% filler.

11 . The aerosol-generating material or slurry of Embodiment 10, comprising about 10- 75wt% filler.

12. The aerosol-generating material or slurry of Embodiment 11 , comprising about 10- 70wt% filler.

13. The aerosol-generating material or slurry of Embodiment 10, comprising about 20- 80wt% filler.

14. The aerosol-generating material or slurry of Embodiment 13, comprising about 20- 75wt% filler.

15. The aerosol-generating material or slurry of Embodiment 14, comprising about 20- 70wt% filler.

16. The aerosol-generating material or slurry of Embodiment 10, comprising about 30- 80wt% filler.

17. The aerosol-generating material or slurry of Embodiment 16, comprising about 30- 75wt% filler.

18. The aerosol-generating material or slurry of Embodiment 17, comprising about 30- 70wt% filler.

19. The aerosol-generating material or slurry of Embodiment 10, comprising about 40- 80wt% filler.

20. The aerosol-generating material or slurry of Embodiment 19, comprising about 40- 75wt% filler. 21 . The aerosol-generating material or slurry of Embodiment 20, comprising about 40- 70wt% filler.

22. The aerosol-generating material or slurry of Embodiment 10, comprising about 50- 80wt% filler.

23. The aerosol-generating material or slurry of Embodiment 22, comprising about 50- 75wt% filler.

24. The aerosol-generating material or slurry of Embodiment 23, comprising about 50- 70wt% filler.

25. The aerosol-generating material or slurry of Embodiment 10, comprising about 60- 80wt% filler.

26. The aerosol-generating material or slurry of Embodiment 25, comprising about 60- 75wt% filler.

27. The aerosol-generating material or slurry of Embodiment 26, comprising about 60- 70wt% filler.

28. The aerosol-generating material or slurry of any preceding embodiment, wherein the filler comprises inorganic filler materials, wood pulp, calcium carbonate, hemp fibre, cellulose and cellulose derivatives.

28a. The aerosol-generating material or slurry of any preceding embodiment, wherein the filler is selected from wood pulp, calcium carbonate, and combinations thereof.

29. The aerosol-generating material or slurry of Embodiment 28, wherein the filler comprises (or is) wood pulp.

30. The aerosol-generating material or slurry of any preceding embodiment, comprising about 1-20 wt% wood pulp.

31. The aerosol-generating material or slurry of Embodiment 30, comprising about 5- 15 wt% wood pulp.

32. The aerosol-generating material or slurry of Embodiment 31 , comprising about 13- 14wt% wood pulp. 33. The aerosol-generating material or slurry of any preceding embodiment, comprising about 10-70wt% calcium carbonate.

34. The aerosol-generating material or slurry of Embodiment 33, comprising about 30- 70wt% calcium carbonate.

35. The aerosol-generating material or slurry of Embodiment 34, comprising about 45- 65wt% calcium carbonate.

36. The aerosol-generating material or slurry of any preceding embodiment, comprising about 1-80wt% of an aerosol-former material.

37. The aerosol-generating material or slurry of Embodiment 36, comprising about 1- 50wt% of an aerosol-former material.

38. The aerosol-generating material or slurry of Embodiment 37, comprising about 5- 35wt% of an aerosol-former material.

39. The aerosol-generating material or slurry of Embodiment 38, comprising about 10- 25wt% of an aerosol-former material.

40. The aerosol-generating material or slurry of Embodiment 39, comprising about 12- 20wt% of an aerosol-former material.

41 . The aerosol-generating material or slurry of Embodiment 40, comprising about 13- 18wt% of an aerosol-former material.

42. The aerosol-generating material or slurry of any preceding embodiment, wherein the aerosol-former material comprises (or is) one or more of glycerol, propylene glycol, 1 ,3-propanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1 ,3-butylene glycol, erythritol, meso-Erythritol, ethyl vanillate, ethyl laurate, a diethyl suberate, triethyl citrate, triacetin, a diacetin mixture, benzyl benzoate, benzyl phenyl acetate tributyrin, laryl acetaee, lauric acid, myristic acid, and propylene carbonate.

43. The aerosol-generating material or slurry of Embodiment 42, wherein the aerosolformer material comprises (or is) one or more of erythritol, propylene glycol, glycerol, and triacetin. 44. The aerosol-generating material or slurry of Embodiment 42, wherein the aerosolformer material comprises (or is) glycerol optionally in combination with propylene glycol.

45. The aerosol-generating material or slurry of any preceding embodiment, comprising about 1-10wt% foam stabilising agent.

46. The aerosol-generating material or slurry of Embodiment 45, comprising about 1- 7wt% foam stabilising agent.

47. The aerosol-generating material or slurry of Embodiment 46, comprising about 1- 5wt% foam stabilising agent.

48. The aerosol-generating material or slurry of Embodiment 45, comprising about 2- 10wt% foam stabilising agent.

49. The aerosol-generating material or slurry of Embodiment 48, comprising about 2- 7wt% foam stabilising agent.

50. The aerosol-generating material or slurry of Embodiment 49, comprising about 2- 5wt% foam stabilising agent.

51. The aerosol-generating material or slurry of any preceding embodiment, wherein the foam stabilising agent comprises (or is) a surfactant.

52. The aerosol-generating material or slurry of Embodiment 51 , wherein the foam stabilising agent comprises (or is) sodium lauryl sulfate (SLS), Tween 60, Tween 80, Amphosol CA, Span 60 (sorbitan monostearate), Span 80 (sorbitan monooleate), lecithin or mixtures thereof.

53. The aerosol-generating material or slurry of any preceding embodiment, comprising about 1-10wt% of effervescent agent.

54. The aerosol-generating material or slurry of Embodiment 53, comprising about 1- 7wt% of effervescent agent.

55. The aerosol-generating material or slurry of Embodiment 54, comprising about 1- 5wt% of effervescent agent.

56. The aerosol-generating material or slurry of Embodiment 53, comprising about 2- 10wt% of effervescent agent. 57. The aerosol-generating material or slurry of Embodiment 56, comprising about 2- 7wt% of effervescent agent.

58. The aerosol-generating material or slurry of Embodiment 57, comprising about 2- 5wt% of effervescent agent.

59. The aerosol-generating material or slurry of Embodiment 53, comprising about 4- 10wt% of effervescent agent.

60. The aerosol-generating material or slurry of Embodiment 59, comprising about 4- 7wt% of effervescent agent.

61. The aerosol-generating material or slurry of Embodiment 60, comprising about 4- 5wt% of effervescent agent.

62. The aerosol-generating material or slurry of any preceding embodiment, wherein the effervescent agent comprises (or is) calcium carbonate, sodium carbonate, sodium bicarbonate, citric acid, tartaric acid, lactic acid, acetic acid, aluminium sulfate or mixtures thereof.

63. The aerosol-generating material or slurry of any preceding embodiment further comprising one or more other functional materials.

64. The aerosol-generating material or slurry of any preceding embodiment, wherein the aerosol-generating material or slurry does not comprise fibrous material.

65. The aerosol-generating material or slurry of any preceding embodiment, wherein the aerosol-generating material or slurry does not comprise tobacco fibres.

66. The aerosol-generating material of any preceding embodiment, wherein the aerosol-generating material consists of, or consists essentially of, one or more foam forming agents, filler, aerosol-former material and water.

67. The aerosol-generating material of any of Embodiments 1-65, wherein the aerosolgenerating material consists of, or consists essentially of, one or more foam forming agents, foam stabilising agent, filler, aerosol-former material and water.

68. The aerosol-generating material of any of Embodiments 1-65, wherein the aerosolgenerating material consists of, or consists essentially of, one or more foam forming agents, filler, aerosol-former material, effervescent agent and water. 69. The aerosol-generating material of any preceding claim, wherein the aerosolgenerating material is present on a support.

70. The aerosol-generating material of any preceding claim, wherein the aerosolgenerating material has a density from 0.02-0.7 g/cm³.

71. The aerosol-generating material of Embodiment 70, wherein the aerosol- generating material has a density from 0.02-0.6 g/cm³.

72. The aerosol-generating material of Embodiment 71, wherein the aerosolgenerating material has a density from 0.02-0.4 g/cm³.

73. The aerosol-generating material of Embodiment 72, wherein the aerosol- generating material has a density from 0.02-0.25 g/cm³.

74. The aerosol-generating material of Embodiment 70, wherein the aerosolgenerating material has a density from 0.06-0.7 g/cm³.

75. The aerosol-generating material of Embodiment 74, wherein the aerosol- generating material has a density from 0.06-0.6 g/cm³.

76. The aerosol-generating material of Embodiment 75, wherein the aerosolgenerating material has a density from 0.06-0.4 g/cm³.

77. The aerosol-generating material of Embodiment 76, wherein the aerosol- generating material has a density from 0.06-0.25 g/cm³.

78. The aerosol-generating material of Embodiment 70, wherein the aerosolgenerating material has a density from 0.1-0.7 g/cm³.

79. The aerosol-generating material of Embodiment 78, wherein the aerosol- generating material has a density from 0.1-0.6 g/cm³.

80. The aerosol-generating material of Embodiment 79, wherein the aerosol- generating material has a density from 0.1-0.4 g/cm³.

81. The aerosol-generating material of Embodiment 80, wherein the aerosol- generating material has a density from 0.1-0.25 g/cm³.

82. The aerosol-generating material of any preceding embodiment, wherein the aerosol-generating material has a fill value more than about 380 cm³/100 g. 83. The aerosol-generating material of Embodiment 82, wherein the aerosolgenerating material has a fill value more than about 400 cm³/100 g.

84. The aerosol-generating material of Embodiment 83, wherein the aerosolgenerating material has a fill value more than about 420 cm³/100 g.

85. The aerosol-generating material of any preceding embodiment, wherein the aerosol-generating material has a Gurley porosity of about 100 s/100 mL or more.

86. The aerosol-generating material of Embodiment 85, wherein the aerosolgenerating material has a Gurley porosity of about 125 s/100 mL or more.

87. The aerosol-generating material of Embodiment 86, wherein the aerosolgenerating material has a Gurley porosity of about 150 s/100 mL or more.

88. An aerosol-generating composition comprising an aerosol-generating material according to any preceding embodiment.

89. The aerosol-generating composition of Embodiment 88 further comprising one or more other functional material.

90. The aerosol-generating composition of Embodiment 89, wherein the other functional materials comprise one or more pH regulators, colouring agents, preservatives, binders, fillers, stabilisers, and/or antioxidants.

91. The aerosol-generating composition of any of Embodiments 88-90, comprising a total of from about 10-100 wt% (WWB) of aerosol-generating material.

92. The aerosol-generating composition of any of Embodiments 88-90, comprising a total of from about 20-100 wt% (WWB) of aerosol-generating material.

93. The aerosol-generating composition of any of Embodiments 88-90, comprising a total of from about 30-100wt% (WWB) of aerosol-generating material.

94. The aerosol-generating composition of any of Embodiments 88-90, comprising a total of from about 40-100 wt% (WWB) of aerosol-generating material.

95. The aerosol-generating composition of any of Embodiments 88-90, comprising a total of from about 50-100 wt% (WWB) of aerosol-generating material. 96. The aerosol-generating composition of any of Embodiments 88-90, comprising a total of from about 60-100 wt% (WWB) of aerosol-generating material.

97. The aerosol-generating composition of any of Embodiments 88-90, comprising a total of from about 70-100 wt% (WWB) of aerosol-generating material.

98. The aerosol-generating composition of any of Embodiments 88-90, comprising a total of from about 50-95 wt% (WWB) of aerosol-generating material.

99. The aerosol-generating composition of any of Embodiments 88-90, comprising a total of from about 50-90 wt% (WWB) of aerosol-generating material.

100. The aerosol-generating composition of any of Embodiments 88-90, consisting of, or consisting essentially of the aerosol-generating material(s).

100a. The aerosol-generating composition of any of Embodiments 88-100, wherein the aerosol-generating composition further comprises tobacco material.

100b. The aerosol-generating composition of Embodiment 100a, wherein the tobacco material is fine-cut.

100c. The aerosol-generating composition of any one of Embodiments 100a-100b, wherein the tobacco material comprises lamina tobacco.

100d. The aerosol-generating composition of any one of Embodiments 100a-100c, wherein the tobacco material comprises cut-rag tobacco.

100e. The aerosol-generating composition of any one of Embodiments 100a-100d, wherein the aerosol-generating material is in the form of a shredded sheet and is blended with the tobacco material.

101. A consumable for use in a non-combustible aerosol provision device, the consumable comprising the aerosol-generating composition of any of Embodiments 88-1 OOe.

101a. A consumable for use in a combustible aerosol provision device, the consumable comprising the aerosol-generating composition of any of Embodiments 88-1 OOe.

102. A non-combustible aerosol provision system comprising the consumable of Embodiment 101 and a non-combustible aerosol provision device. 102a. A combustible aerosol provision system comprising the consumable of Embodiment 101a and a combustible aerosol provision device.

103. The consumable for use in a non-combustible aerosol provision device of Embodiment 101 , or the non-combustible aerosol provision system of Embodiment 93, wherein the non-combustible aerosol provision device is a heat-not-burn device.

104. The consumable for use in a non-combustible aerosol provision device of Embodiment 101 , or the non-combustible aerosol provision system of Embodiment 102, wherein the non-combustible aerosol provision device is an electronic tobacco hybrid device.

105. A method of forming an aerosol-generating material as defined in any of Embodiments 1-87, the method comprising

(a) providing a slurry comprising:

(i) one or more foam forming agents;

(ii) filler;

(iii) aerosol-former material; and

(iv) solvent;

(b) aerating the slurry;

(c) forming a layer of the aerated slurry; and

(d) drying the slurry to form the aerosol-generating material.

105a. A method of forming an aerosol-generating material as defined in any of Embodiments 1-87, the method comprising

(a) providing a slurry comprising:

(v) one or more foam forming agents;

(vi) filler;

(vii) aerosol-former material; and

(viii) solvent;

(b) forming a layer of the slurry;

(c) aerating the slurry; and

(d) drying the slurry to form the aerosol-generating material.

105b. The method according to Embodiment 105a, wherein step (c) comprises bubbling a gas through the slurry. 106. The method according to Embodiment 105, wherein step (b) comprises mixing the slurry under high shear conditions.

106a. The method according to Embodiment 105, wherein step (b) comprises bubbling a gas through the slurry.

107. The method according to Embodiment 105 or 106, wherein step (a) of providing the slurry comprises mixing the slurry under high shear conditions, such that step (b) is part of step (a).

108. A method of forming an aerosol-generating material as defined in any of Embodiments 1-87, the method comprising

(a) providing a slurry comprising:

(i) one or more foam forming agents;

(ii) filler;

(iii) an effervescent agent;

(iv) aerosol-former material; and

(v) solvent;

(b) forming a layer of the slurry;

(c) drying the slurry to form the aerosol-generating material.

108a. The method according to Embodiment 108, wherein step (b) gas is bubbled through the slurry before the drying step.

108. The method of any of Embodiments 105-108, wherein the solvent comprises water.

109. The method of any of Embodiments 105-107, wherein the solvent consists essentially of, or consists of water.

110. The method of any of Embodiments 105-107, wherein the slurry comprises from about 50 wt%, 60 wt%, 70 wt%, 80 wt% or 90 wt% of solvent (WWB).

Examples

Exemplary and non-limiting formulations for aerosol-generating materials are provided in Table 1.

Table 1. Example formulations

Table 2. Results

Table 3. Results

The aerosol-generating material of the present invention provides a substrate having reduced weight but good sensory. The use of a foam forming agent (e.g. HPMC) allows air to be incorporated into the thin film and the density to be decreased (Table 3).

Claims

55 CLAIMS

1. An aerosol-generating material comprising:

(i) one or more foam forming agents;

(ii) filler; and

2. The aerosol-generating material according to claim 1, wherein the aerosolgenerating material further comprises a foam stabilising agent.

3. The aerosol-generating according to claim 1 or 2, wherein the aerosolgenerating material comprises an effervescent agent.

4. The aerosol-generating material according to any of claims 1 to 3, wherein the aerosol-generating material is porous.

5. The aerosol-generating material according to any of claims 1 to 4, wherein the aerosol-generating material has a density from about 0.02 g/cm³ to about 0.6 g/cm³.

6. The aerosol-generating material according to any of claims 1 to 5, wherein the aerosol-generating material has a density from about 0.02 g/cm³ to about 0.5 g/cm³.

7. The aerosol-generating material according to any of claims 1 to 6, wherein the aerosol-generating material has a density from about 0.02 g/cm³ to about 0.4 g/cm³.

8. The aerosol-generating material according to any of claims 1 to 7, wherein the foam forming agent comprises hydroxypropyl methylcellulose (HPMC), guar gum, modified starch such as hydroxylated starch, maltodextrin, or mixtures thereof.

9. The aerosol-generating material according to any of claims 1 to 8, wherein the foam forming agent comprises HPMC. 56

10. The aerosol-generating material according to any of claims 1 to 9, wherein the filler comprises calcium carbonate, wood pulp, or combinations thereof.

11. The aerosol-generating material according to any of claims 1 to 10, wherein the filler comprises wood pulp or a combination of wood pulp and calcium carbonate.

12. The aerosol-generating material according to any of claims 1 to 11 , wherein the aerosol-generating material comprises from about 5 to about 35 wt% foam forming agent.

13. The aerosol-generating material according to any of claims 1 to 12, wherein the aerosol-generating material comprises from about 6 to about 25 wt% foam forming agent.

14. The aerosol-generating material according to any of claims 1 to 13, wherein the aerosol-generating material comprises from about 10 to about 20 wt% foam forming agent.

15. The aerosol-generating material according to any of claims 1 to 14, wherein the aerosol-generating material comprises from about 10 to about 85 wt% filler.

16. The aerosol-generating material according to any of claims 1 to 15, wherein the aerosol-generating material comprises from about 50 to about 80 wt% filler.

17. The aerosol-generating material according to any of claims 1 to 16, wherein the aerosol-generating material has a fill value of more than about 380 g/cm³.

18. The aerosol-generating material according to claim 17, wherein the value is measured according to Method A as described herein.

19. The aerosol-generating material according to any of claims 1 to 18, wherein the aerosol-generating material has a Gurley porosity of about 100 s/100 mL or more.

20. The aerosol-generating material according to any of claims 1 to 19, wherein the aerosol-generating material has a Gurley porosity of about 150 s/100 mL or more. 57

21. The aerosol-generating material according to claim 19 or 20, wherein the Gurley porosity is measured according to Method B as described herein.

22. The aerosol-generating material according to claim 2, wherein the foam stabilising agent comprises one or more surfactants.

23. The aerosol-generating material according to any of claims 1 to 22, wherein the aerosol-generating material comprises from about 1 to about 5 wt% foam stabilising agent.

24. The aerosol-generating material according to claim 22 or 23, wherein the foam stabilising agent comprises sodium lauryl sulfate (SLS), Tween 60, Tween 80, Amphosol CA, Span 60 (sorbitan monostearate), Span 80 (sorbitan monooleate), lecithin or mixtures thereof.

25. The aerosol-generating material according to claim 3, wherein the effervescent agent comprises calcium carbonate, sodium carbonate, sodium bicarbonate, citric acid, tartaric acid, acetic acid, aluminium sulfate or mixtures thereof.

26. The aerosol-generating material according to any of claims 1 to 25, wherein the aerosol-generating material is substantially free from tobacco.

27. An aerosol-generating composition comprising the aerosol-generating material of any of claims 1 to 26.

28. The aerosol-generating composition according to claim 27, wherein the aerosol-generating material comprises tobacco.

29. The aerosol-generating composition of any of claims 25-26, comprising about 10-100 wt% (WWB) of aerosol-generating material.

30. The aerosol-generating composition of claim 27 or 29, wherein the aerosolgenerating composition further comprises tobacco material. 58

31 . The aerosol-generating composition of claim 30, wherein the tobacco material is fine-cut.

32. The aerosol-generating composition of any one of claims 30-31 , wherein the tobacco material comprises lamina tobacco.

33. The aerosol-generating composition of any one of claims 30-32, wherein the tobacco material comprises cut-rag tobacco.

34. The aerosol-generating composition of any one of claims 30-33, wherein the aerosol-generating material is in the form of a shredded sheet and is blended with the tobacco material.

35. A consumable for use in a non-combustible aerosol provision device, the consumable comprising the aerosol-generating composition of any of claims 27-34.

36. A consumable for use in a combustible aerosol provision device, the consumable comprising the aerosol-generating composition of any of claims 27-34.

37. A non-combustible aerosol provision system comprising the consumable of claim 35 and a non-combustible aerosol provision device, the non-combustible aerosol provision device comprising an aerosol-generating device arranged to generate aerosol from the consumable when the consumable is used with the non-combustible aerosol provision device.

38. A combustible aerosol provision system comprising the consumable of claim 36 and a combustible aerosol provision device.

39. A method of forming an aerosol-generating material, the method comprising:

(a) providing a slurry comprising:

(i) one or more foam forming agents;

(ii) filler;

(iii) aerosol-former material; and

(iv) solvent;

(b) aerating the slurry; (c) forming a layer of the aerated slurry;

(d) drying the slurry to form the aerosol-generating material.

40. The method according to claim 39, wherein step (b) comprises mixing the slurry under high shear conditions.

41. The method according to claim 39 or 40, wherein step (a) of providing the slurry comprises mixing the slurry under high shear conditions, such that step (b) is part of step (a).

42. The method according to claim 39, wherein step (b) comprises bubbling a gas through the slurry.

43. A method of forming an aerosol-generating material, the method comprising:

(a) providing a slurry comprising:

(i) one or more foam forming agents;

(ii) filler;

(iii) an effervescent agent;

(iv) aerosol-former material; and

(v) solvent;

(b) forming a layer of the slurry;

(c) drying the slurry to form the aerosol-generating material.

44. The method according to any of claims 39-43, wherein gas is bubbled through the slurry before the drying step.

45. The method according to any of claims 39-44, wherein the solvent is water.