EP3297460A1

EP3297460A1 - Aerosol generating material and devices including the same

Info

Publication number: EP3297460A1
Application number: EP16727967.8A
Authority: EP
Inventors: Walid Abi Aoun; Bryan ALLBUTT; Edward Dennis John
Original assignee: British American Tobacco Investments Ltd IFI
Current assignee: Nicoventures Trading Ltd
Priority date: 2015-05-20
Filing date: 2016-05-19
Publication date: 2018-03-28
Anticipated expiration: 2036-05-19
Also published as: BR112017024789A2; JP2018515119A; GB201508671D0; RU2675474C1; US20180279666A1; JP6695359B2; CN107846963A; HK1245589A1; EP3297460B1; WO2016184977A1

Abstract

There is provided a solid aerosol generating material comprising about 5-35 wt% tobacco extract; about 50-80 wt% filler; about 10-35 wt% aerosol generating agent; and about 2.5-10 wt% binder; wherein weight percentage is calculated on a dry weight basis.

Description

AEROSOL GENERATING MATERIAL AND DEVICES INCLUDING THE

SAME

Technical Field

The present invention relates to aerosol generating material which emits an aerosol and/or gas on heating.

Background

Tobacco material is heated in smoking articles for the purpose of releasing substances contained in the material and delivering these as an aerosol.

In many smoking articles, combustion of tobacco material releases thermal energy which in turn releases a smoke aerosol from the tobacco material. Combustion causes various physico-chemical degradation processes, which may be a combination of oxidative degradation, pyrolysis, pyrosynthesis, and distillation. The thermal energy generated by combustion tends to be high, however, and the amount of heat released is often difficult to control.

In other smoking articles, the heat providing the thermal energy needed to release an aerosol is provided by electrical heating.

Heat not burn devices (also known as tobacco heating devices or tobacco heating products) are non-combustion type smoking articles, developed as an alternative to conventional, combustible cigarettes. These devices volatilise components of tobacco by heating the tobacco material, suitably by electrical heating (although other means of heating could be used); pyrolysis or combustion of the tobacco or volatiles is avoided. The volatilised components condense to form an inhaiabie aerosol. Summary

According to a first aspect of the invention, there is provided a solid aerosol generating material comprising about 5-35 wt% tobacco extract, about 50-80 wt% filler, about 10-35 wt% aerosol generating agent and about 2.5- 10 wt% binder.

In use, the aerosol generating material is heated to generate at least one delivery of an inhalable aerosol and/or gas. In some cases, the aerosol generating material may be heated to generate multiple deliveries of an inhalable aerosol and/or gas.

All percentages by weight described herein (denoted wt%) are calculated on a dry weight basis, unless explicitly stated otherwise. All weight ratios are also calculated on a dry weight basis. A weight quoted on a dry weight basis refers to the whole of the extract or slurry or material, other than the water, and may include components which by themselves are l iquid at room temperature and pressure, such as glycerol. Conversely, a wet weight refers to all components, including water.

In some embodiments, the aerosol generating material is in the form of a sheet.

In some embodiments, the filler comprises an inorganic material such as calcium carbonate, perlite, vermiculite, diatomaceous earth, colloidal silica, magnesium oxide, magnesium sulphate and magnesium carbonate. In some embodiments, the filler comprises chalk. In some cases, the filler comprises an organic material such as wood pulp, cellulose and cellulose derivatives. In some embodiments, the aerosol generating agent comprises a polyol such as sorbitol, glycerol, and glycols like propylene glycol or triethylene glycol; a non-polyol such as monohydric alcohols, high boiling point hydrocarbons, acids such as lactic acid, glycerol derivatives, esters such as diacelin, triacetin, methylene glycol diacetate, triethyl citrate or myri states including ethyl myri state and isopropyl myri state and aliphatic carboxvlic acid esters such as methyl stearate, dimethyl dodecanedioate and dimethyl tetradecanedioate. In some embodiments, the aerosol generating agent comprises glycerol or propylene glycol.

In some embodiments, the binder comprises alginate, celluloses or modified celluloses, starches or modified starches, or natural gums. In some embodiments, the binder comprises an alginate such as sodium alginate, calcium alginate, potassium alginate or ammonium alginate.

In some embodiments, the aerosol generating material is a cast material.

According to a second aspect of the present invention, there is provided a component for aerosol generation by electrical heating, the component comprising an aerosol generating material as described herein and an electrically resistive heating element, wherein the elect ically resistive heating element is at least partially embedded in the aerosol generating material.

According to a third aspect of the present invention, there is provided a device for generating an inhalable aerosol and/or gas, the device comprising an aerosol generating material as described herein and a heating means which volatilises components in use to form an aerosol and/or gas.

In some embodiments, the heating means is an electrical heating means. In some embodiments, the electrical heating means is an electrically resistive heating element.

In some embodiments, the heating means is at least partially embedded in the aerosol generating material. In some embodiments, the device for generating an inhalable aerosol and/or gas, comprises a component for aerosol generation by electrical heating as described herein.

In some embodiments, the device is a tobacco heating product (also known as a heat not bum device or a tobacco heating device).

According to a fourth aspect of the present invention, there is provided a slurry for forming an aerosol generating material as described herein, comprising water, about 5-35 wt% tobacco extract, about 50-80 wt% filler, about 10-35 wt% aerosol generating agent and about 2.5- 1 0 wt% binder.

According to a fifth aspect of the inventi n, there is provided a method of making an aerosol generating material as described herein. The method comprises the steps of (a) providing a slurry comprising the components of the aerosol generating material and water, (b) casting, extruding or spraying the slurry, and (c) drying the slurry to form the solid aerosol generating material.

According to a sixth aspect of the invention, there is provided the use of an aerosol generating material as described herein, a component as described herein or a device as described herein, to generate an aerosol and/or gas.

To the extent that they are compatible, optional or preferable features of each aspect of the invention may be combined with other aspects of the invention defined herein. Speci ically, features of the aerosol generating material described herein may be applicable to the component for aerosol generation, the device for generating an inhalable aerosol and/or gas, the slurry for making the aerosol generating material and methods of making the aerosol generating material, and v ice versa. Further features and advantages of the invention wil l become apparent from the following description of preferred embodiments of the invention, given by way of example only.

Detailed Description

The present invention relates to an aerosol generating material that may be heated to emit an inhalable aerosol and to devices incorporating the same.

More specifically, the present invention provides a solid aerosol generating material comprising about 5-35 wt% tobacco extract, about 50-80 wt% filler, about 10-35 wt% aerosol generating agent and about 2.5-10 wt% binder.

The invention also provides a component for aerosol generation by electrical heating comprising an aerosol generating material as described herein and an electrically resistive heating element, wherein the electrically resistive heating element is at least partially embedded in the aerosol generating material.

The invention also provides a device for generating an inhalable aerosol and/or gas, the device comprising an aerosol generating material as described herein. In some embodiments, the device comprises a component for aerosol generation as described herein.

The inventors have found that specific amounts of the various components must be included in the aerosol generating material. As set out in detail below, the aerosol generating material is generally a cast or extruded material, suitably formed from a slurry of the constituent components. If the relative proportions of the constituents are incorrect, the binder may gel, the slurry solids content may be too high and/or the slurry may be too viscous (or conversely, not viscous enough), thereby preventing casting or extrusion. Additionally, the aerosol generating materials defined herein produce an aerosol with acceptable characteristics such as taste and density, whilst forming the aerosol efficiently and effectively.

Tobacco extract

The aerosol generating material comprises a tobacco extract. A tobacco extract is a composition of tobacco that is obtained by a method comprising the treatment of tobacco with a solvent, and may further comprise other treatment steps ( such as concentration). The extract may be formed by the treatment of any suitable tobacco, such as single grades or blends, cut rag or whole leaf, including Virginia and/or Buriey and/or Oriental tobacco.

The solid aerosol generating material comprises about 5-35 wt% tobacco extract. In some embodiments, the aerosol generating material comprises 5- 25wt%, 5-20 wt%, 10-20 wt% or 10- ! 5 wt% tobacco extract. In some embodiments, it may comprise at least about 5%, 7%, 10% or 12% by weight of tobacco extract. In some embodiments, it may comprises less than about 35%, 25%, 20%, 18% or 15% by weight of tobacco extract. In some embodiments, the solid aerosol generating material comprises about 12 wt% tobacco extract.

In some embodiments, the tobacco extract may be obtained by a method comprising the treatment of tobacco with water. In some embodiments, the treatment of tobacco with water may comprise adding water to tobacco, separating the resulting water-based liquid extract from the insoluble portion of tobacco feedstock, and optionally removing excess water to form a tobacco extract. Any suitable filtration methods may be used, such as centrifugal solids filtration or vacuum fluidised bed filtration. Any suitable evaporative concentration methods may be used, such as vacuum spinning disk, vacuum falling, or rising film evaporation. Techniques including spray-drying or freeze - drying may also be utilised to reduce/remove water content. Such processes would be known to those skilled in the art of filtration and evaporative concentration.

In some embodiments, tobacco extract may be obtained by a method comprising steps for altering the pH of the solution. In some embodiments, the pH of the tobacco extract may be greater than or equal to about 6, 6.5, 7, 7.5, 8 or 9. In some cases, the pH of the tobacco extract is less than or equal to about 10.5, 10 or 9.5. In some embodiments, the pH of the tobacco extract is greater than or equal to about 7. In some embodiments, the pH of the tobacco extract is about 7. The steps for altering the pFI of the solution may comprise the addition of an alkaline material, suitably a carbonate such as lithium, sodium, potassium or calcium carbonate, to the solution to increase the pH. In some embodiments, the water extract solution is acidic (pH around 5.2) and, on addition of a metal carbonate, the pi 1 is adjusted to give a tobacco extract solution with pH of greater than or equal to about 7. The inventors have found that a tobacco extract with a pH in the claimed range reduces excessive gelling on addition to a slurry, giving a mixable slurry that is easily proces sable into a homogenous aerosol generating material. The slurry viscosity is such that the slurry can be easily cast or extruded. If the pH of the tobacco extract is too acidic, the pH of the slurry may drop causing solvation of metal ions (such as calcium ions from chalk), which in turn cause excessive gelation.

In some embodiments, tobacco extract may be obtained by a method comprising extraction using a supercritical fluid, e.g. supercritical carbon dioxide. In some other embodiments, tobacco extract may be obtained by a method comprising extraction with a solvent which may comprise a polyol or other suitable higher boiling liquids. In some cases, the extraction solvent may comprise glycerol and/or propylene glycol (and optionally water). In some embodiments, the tobacco extract may be prepared by a method comprising steps for removing or reducing the concentration of certain substances. For example, the tobacco extract may be treated with bentonite to reduce protein content, and/or polyvinyl olypyrrolidone to reduce polyphenol content.

In some embodiments, the tobacco extract may be prepared by a method comprising steps for adding or increasing the concentration of one or more substances. In some of these embodiments, aerosol generating agents and/or flavourants may be added, for example.

A tobacco extract included in the aerosol generating material in the devices of the invention may have any suitable chemical composition. The solid content of the tobacco extract may be at least about 2%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% 50%, 60%, 75%, 80%, 85%, 90% or 95% on a wet weight basis (total weight including water). The tobacco extract may have a pH in the range of 5 to 9, suitably 6 to 8, 6.5 to 7.5 or about 7.

Filler

The aerosol generating material comprises a filler. Suitably the filler may comprise one or more inorganic filler materials, which include, but are not limited to: calcium carbonate, perlite, vermiculite, diatomaceous earth, colloidal silica, magnesium oxide, magnesium sulphate, magnesium carbonate, and suitable inorganic sorbents, such as molecular sieves. Chalk is particularly suitable. In some cases, the filler may comprises one or more organic filler materials, which include, but are not limited to: wood pulp, cellulose and cellulose derivatives.

The filler material may be selected to have one or more purposes. In some embodiments, it may act as a sorbent and/or support for other substances in the aerosol generating material. In some embodiments, it may act as a structure for adsorbing other substances before releasing them on heating. In some embodiments, it may act as a sorbent and/or support for an aerosol generating agent, such as glycerol, and/or any other substances that influence the sensory characteristics of the aerosol generated on heating.

In some embodiments, an inorganic filler material may be included in the aerosol generating material to provide additional strength. In some embodiments, it may be included to help retain the tobacco extract within the aerosol generating material and to provide an aerosol generating material with suitable strength for subsequent processing/utilisation. The aerosol generating material comprises about 50-80 wt% filler, suitably an inorganic filler material. In some embodiments, the aerosol generating material comprises 60-80 wt% or 65-75 wt% filler. In some embodiments, it may comprise at least about 50%, 55%, 60%, 65% or 67% by weight of filler. In some embodiments, it may comprise less than about 80%, 78%, 75% or 70% by weight of filler. In some embodiments, the solid aerosol generating material comprises about 67 wt% filler. In these embodiments, the filler may comprise, substantially consist of or consist of chalk.

A filler material is necessary to give the solid aerosol generating material a dry consistency which means that the material can be processed down-stream

(shredded, blended, rolled, crimped, shaped etc.). If the filler content is too low, the aerosol generating material is not processable; the material is typically tacky or sticky. Additionally, the inventors believe that the filler material, and in particular chalk, increases the strength of the aerosol generating material, prevents migration of the aerosol generating agent (i.e. ensures a uniform composition) and minimises unwanted water uptake (i.e. the material is then less hygroscopic).

However, the inventors have also established that, i the filler content is too high, the aerosol generating material is difficult to form. In some embodiments, the aerosol generating material is formed from a slurry (as discussed in detail herein) and, if the filler content is high, the slurry is difficult to process because the solid content is too high. A high filler content makes it difficult to cast the slurry (although extrusion may be possible). Additionally, if the filler content is too high it may insulate the volatilisable components of the aerosol generating material, thereby necessitating the use of more energy to form an aerosol and to consume all of the material. The inventors have established that the filler content defined herein provides a good balance of these properties.

Aerosol generating agent

The aerosol generating material comprises an aerosol generating agent. In this context, an "aerosol generating agent" is an agent that promotes the generation of an aerosol. An aerosol generating agent may promote the generation of an aerosol by promoting an initial vapourisation and/or the condensation of a gas to an inhalable solid and/or liquid aerosol. In some embodiments, an aerosol generating agent may improve the delivery of flavour from the aerosol generating material.

Any suitable aerosol generating agent or agents may be included in the aerosol generating material of the invention. Suitable aerosol generating agents include, but are not limited to: a polyol such as sorbitol, glycerol, and glycols like propylene glycol or methylene glycol; a non-polyol such as monohydric alcohols, high boiling point hydrocarbons, acids such as lactic acid, glycerol derivatives, esters such as diacetin, triacetin, Methylene glycol diacetate, triethyl citrate or my i states including ethyl myristate and isopropyl my i state and aliphatic carboxylic acid esters such as methyl stearate, dimethyl dodecanedioate and dimethyl tetradecanedioate. Suitably, the aerosol generating agent may comprise, substantially consist of, or consist of glycerol, propylene glycol, triacetin and/or ethyl myristate. In some cases, the aerosol generating agent may comprise, substantially consist of, or consist of glycerol and/or propylene glycol. I I

The solid aerosol generating material comprises about 10-35 wt aerosol generating agent. In some embodiments, the aerosol generating material comprises 10-30 wt%, 15-25 wt% or 15-20 wt% aerosol generating agent. In some embodiments, it may comprise at least about 10%, 12% or 15% by weight of aerosol generating agent. In some embodiments, it may comprise less than about 35%, 30%, 25% or 20% by weight of aerosol generating agent.

A minimum amount of aerosol generating agent is required to efficiently and effectively generate an aerosol. However, the inventors have found if the amount of aerosol generating agent is too high, the aerosol generating material is difficult to form. In some embodiments, the aerosol generating material is formed from a slurry (as discussed in detail herein) and, i the aerosol generating agent content is high, the resulting aerosol generating material is too tacky/sticky/hygroscopic to allow processing into a consumable product. The inventors have established that the aerosol generating agent content defined herein provides a good balance of these properties.

Binder

The aerosol generating material comprises 2.5-10 wt% binder. In some embodiments, the binder comprises one or more of an alginate, celluloses or modified celluloses, starches or modified starches, and natural gums.

Suitable binders include, but are not limited to: alginate salts comprising any suitable cation; celluloses or modified celluloses, such as hydroxypropyl cellulose and carboxymethylcellulose; starches or modified starches; polysaccharides such as pectin salts comprising any suitable cation, such as sodium, potassium, calcium or magnesium pectate; xanthan gum, guar gum, and any other suitable natural gums; and mixtures thereof. In some embodiments, the binder comprises, substantially consists of or consists of one or more alginate salts selected from sodium alginate, calcium alginate, potassium alginate or ammonium alginate. In some embodiments, the aerosol generating material comprises 5- 10 wt%, 6-9 wt%, 6-8 wt% or 6-7 wt% binder. In some embodiments, it may comprise at least about 2.5%, 3%, 4%, 5% or 6% by weight of binder. In some embodiments, it may comprises less than about 10%, 9%, 8% or 7% by weight of binder. In some embodiments, the aerosol generating material comprises 6.2-6.8 wt% binder. In some embodiments, the aerosol generating material contains more tobacco extract (dry weight) than binder.

The binder increases the toughness or strength of the aerosol generating material. It also increases the viscosity of the slurry used to form the aerosol generating material, allowing it to be cast or extruded (for example) and to retain the desired shape. However, higher binder contents are undesirable because the slurries used to form the aerosol generating material may become too viscous to allow casting. Additionally, the cost of such aerosol generating materials increases with the binder content level.

The inventors have also found that the weight ratio of tobacco extract to binder (such as alginate) is important because ions present in the tobacco extract can cause the binder to gel excessively and cause syneresis; at the weight ratios claimed, excessive gelation and syneresis are minimised. Thus, the inventors have determined suitable maximum binder contents.

Alginate salts are derivatives of alginic acid and are typically high molecular weight polymers (10-600 kl )a ). Alginic acid is a copolymer of β-D-mannuronic (M) and a-L-guluronic acid (G) units (blocks) linked together with (l,4)-glycosidic bonds to form a polysaccharide. The inventors have determined that alginate salts with a high M monomer content are less susceptible to undesired gelling on contact with tobacco extract and accordingly, syneresis is reduced when using an alginate with a high M monomer content. The binder may therefore comprise an alginate salt in which at least about 40%, 45%, 50%, 55%, 60% or 70% of the monomer units in the alginate copolymer are β-D-mannuronic units.

Further optional components

In some embodiments, one or more further components may be included in the aerosol generating material.

In some embodiments, additional ingredients may be included in the aerosol generating material for amelioration of sensory characteristics of the aerosols generated. In some cases, water, flavourings, casings, or substances which may be acidic or basic in character may alter the taste, flavour, and sensory impact of the aerosol. In some embodiments, these additional ingredients may lead to a milder or mellow effect. In some embodiments, they may lead to more pronounced sensory effects.

In some embodiments, the aerosol generating material may comprise water. Water may be included for any suitable purpose, and may be included having been purified using any suitable method of purification, such as reverse osmosis, distillation, and/or ion exchange. In some embodiments, it may be included to moisten the material. Alternatively or in addition, i may be included to modify the sensory characteristics of the aerosol and/or gas generated from the material on heating. Any suitable quantity of water may be included in the aerosol generating material. For example, in some embodiments, the aerosol generating material may comprise about 1-25%, 1- 15%, 3- 15%, 3- 10%, 7- 10% or about 3-7% water by weight on a wet weight basis (i.e. by weight of the total composition including water).

In some embodiments, the aerosol generating material may comprise one or more compounds for the purpose of lowering the boiling point of one or more other substances in the aerosol generating material. In some of these embodiments, the aerosol generating material may comprise one or more compounds for the purpose of forming an azeotrope with one or more other substances in the aerosol generating material.

In some embodiments, the aerosol generating material may comprise one or more flavou rants. As used herein, the terms "flavour" and "flavourant" refer to materials which, where local regulations permit, may be used to create a desired taste or aroma in a product for adult consumers.

The terms "flavour" and "flavourant" may include extracts (e.g., licorice, hydrangea, Japanese white bark magnolia leaf, chamomile, fenugreek, clove, menthol, Japanese mint, aniseed, cinnamon, herb, wintergreen, cherry, berry, peach, apple, Drambuie, bourbon, scotch, whiskey, spearmint, peppermint, lavender, cardamom, celery, cascarilla, nutmeg, sandalwood, bergamot, geranium, honey essence, rose oil, vanilla, lemon oil, orange oil, cassia, caraway, cognac, jasmine, ylang-ylang, sage, fennel, piment, ginger, anise, coriander, coffee, or a mint oil from any species of the genus Mentha), 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, oil, liquid, or powder.

In some embodiments, the aerosol generating material may comprise one or more colourants. In some embodiments, the aerosol generating material may be coloured such that it resembles components of a conventional, combustible cigarette. In some embodiments a caramel colourant may be included in the aerosol generating material. In some embodiments, the aerosol generating material may comprise heat-conducting particles. These may improve the rate of heat transfer in use through the aerosol generating material. In some embodiments, the aerosol generating material may additionally comprise a further tobacco material in addition to tobacco extract, such as ground tobacco, tobacco fibre, cut tobacco, extruded tobacco, tobacco stem and/or reconstituted tobacco. Component for aerosol generation

The component for aerosol generation by electrical heating comprises the aerosol generating material described herein and an electrically resistive heating element, wherein the heating element is at least partially embedded in the aerosol generating material.

By "electrically resistive heating element", it is meant that on application of a current to the element, resistance in the element transduces electrical energy into thermal energy which heats the aerosol generating material.

The heating element may be in the form of a mesh, coil or a plurality of wires. The heating element may comprise a metal or metal alloy. Metals are excellent conductors of electricity and thermal energy. Suitable metals include but are not limited to: copper, aluminium, platinum, tungsten, gold, silver, and titanium. Suitable metal alloys include but are not limited to: nichrome and stainless steel.

The component for aerosol generation may be formed by casting, extruding or spraying a slurry onto the heating element, the slurry comprising the components of the aerosol generating material and water. The component may be in sheet form.

Device for generating an inhalable aerosol and/or gas

The device comprises an aerosol generating material as described herein and a heating means which volatilises components in use to form an aerosol and/or gas. In some embodiments, the heating means is an electrical heating means.

In some embodiments, the heating means is at least partially embedded in the aerosol generating material. In some embodiments, the electrical heating means is an electrically resistive heating element.

In some embodiments, the device comprises a component for aerosol generation as described herein.

In some embodiments, the heating of the aerosol generating material does not result in any significant combustion of the material. In some embodiments, the heating results in no combustion or essentially no combustion of the aerosol generating material. In some embodiments, the device is a heat not burn device, also known as a tobacco heating device or a tobacco heating product. Such devices are non-combustion type smoking articles, developed as an alternative to conventional, combustible cigarettes. These devices volatilise components of tobacco by heating the tobacco material; pyrolysis or combustion of the tobacco or volatiles is avoided. The volatised components condense to form an inhalable aerosol. The aerosol often comprises water, a humectant, nicotine and optionally other tobacco components such as flavours and aromas. Thus, in some embodiments, the device is one in which tobacco is heated to volatilise components without pyrolysis or combustion of the tobacco. Using electricity to heat aerosol generating material in a smoking article has many advantages. In particular, it has many advantages over using combustion. Combustion is a complex process that generates aerosols by a combination of interactive physico-chemical processes which may include oxidative degradation, pyrolysis, pyrosynthesis, and distillation. It generally leads to the generation of complex aerosols. For example, smoke arising from a combustible smoking article comprising tobacco is a complex, dynamic mixture of more than 5000 identified constituents. The exothermic processes of combustion may be self-sustaining, and may result in heat generation rates, and heat output quantities, sufficient for degradation of the combustible matrix. In some cases, the matrix may be completely degraded to an ash residue which may comprise inorganic, non-combustible materials. Very high temperatures can be reached in burning cigarettes due to the exothermic reaction of combustion. In between taking puffs of a cigarette (the inter-puff smouldering period), the centre of the burning zone in the tobacco rod of the cigarette can reach temperatures as high as 800°C. During taking a puff of a cigarette, the periphery of the burning zone in the tobacco rod of the cigarette can reach temperatures as high as 910°C. Using electrical resistance heating systems (such as some heat not burn devices, also known as tobacco heating products or tobacco heating devices) is advantageous because the rate of heat generation is easier to control, and lower levels of heat are easier to generate, compared with using combustion for heat generation. In some embodiments, the device includes an actuator, which allows the user to initiate electrical heating.

The use of electrical heating systems therefore allows greater control over the generation of an aerosol and/or gas from aerosol generating materials. Furthermore, it allows for aerosol and/or gas to be generated without combustion taking place, rather than through combustive degradation. Electrical heating systems can also facilitate the generation of an aerosol and/or gas from inherently non-combustible materials, such as inorganic sorbents with ingredients that generate an aerosol and/or gas when heated.

In some embodiments, the devices of the invention are able to provide multiple deliveries or doses of aerosol and/or gas. This means that the aerosol generating material may be heated to produce sufficient aerosol and/or gas to allow multiple puffs. This may be achieved by heating the aerosol generating material for a period of time sufficient to produce a volume of aerosol and/or gas suitable for multiple deliveries. In some embodiments, this may involve heating the aerosol generating material constantly. Alternatively, this may involve successive, shorter periods of heating the aerosol generating material, optionally with each period producing a single delivery or dose of aerosol and/or gas. In some embodiments, the device is capable of heating the aerosol generating material to a temperature sufficient to significantly increase the rate of evaporation and/or sublimation of a substance in the aerosol generating material, but insufficient to initiate combustion. This may be the case when the device is a heat not burn device. In some other embodiments, the device is capable of heating the aerosol generating material to a temperature sufficient to initiate combustion. This may be the case when the device is a combustible device.

In some embodiments, the device may be configured to heat the aerosol generating material to a temperature of between about 50-400°C, 100-350°C, 150-350 ( \ 150-330°C, or 180-300°C.

In some embodiments, the aerosol generating material may be provided in a cartridge, and the cartridge may be msertable into the device. In some of these embodiments, this cartridge may be replaceable. In some embodiments, the cartridge may be combined with other parts of the aerosol generating device in any suitable way. In some embodiments, it may be attached to other parts of the device by a friction fit and/or a screw fit and/or a press fit.

Method of making the aerosol generating material

In some embodiments, the aerosol generating material is made from a slurry, the slurry comprising the components of the aerosol generating material and water. In some embodiments, the slurry is extruded or cast and then dried to form the aerosol generating material. In alternative embodiments, the slurry may be sprayed and then dried to form the aerosol generating material. In some embodiments, the method of making the aerosol generating material further comprises the initial step of making the slurry.

To form the slurry, the components of the aerosol generating material may be added in any suitable order. In some embodiments, the slurry may undergo mixing during and/or after the addition of its components and, in these embodiments, may undergo mixing for any suitable length of time. The length of time over which the slurry undergoes mixing will depend on its composition and volume, and may be varied accordingly. In some embodiments, the slurry may undergo mixing as necessary to make the composition of the slurry substantially homogeneous and to ensure that the slurry has the required flow and viscosity characteristics for casting.

Phase separation of slurries used to from the aerosol generating material defined herein is minimal at the weight ratios of tobacco extract to binder defined herein. At low binder concentrations, the inventors have observed separation of water from the slurry. Thus, the inventors have established that a minimum binder quantity is necessary as defined herein. The inventors have also established that the binder to water weight ratio is important in reducing/minimising or preventing syneresis. The wet weight ratio of tobacco extract to binder in the slurry may be in the range of about 10: 1 to about 2: 1 , suitably about 6: 1 to about 3: 1. The weight ratio of water ( including water present in other components, such as water used as a solvent in the tobacco extract) to binder may be in the range of about 100: 1, 80: 1 or 75: 1 to about 50: 1, 30: 1 or 25: 1.

In some embodiments, the method of the invention comprises steps for obtaining a tobacco extract, as set out above. The resulting tobacco extract may be added to the slurry.

In some embodiments, the method of making a slurry may comprise the steps of (1) mi ing the glycerol and binder, (2) adding water and mixing. (3) adding filler and mixing, (4) adding tobacco extract and mixing to form a smooth slurry. The mixing after addition of tobacco extract will typically be a high shear mixing. In embodiments in which the binder is a solid, step (1) creates a dispersion/suspension of the binder in the aerosol generating agent.

In some embodiments, the method of making a slurry may comprise the steps of (1) adding the binder to the water and mixing, (2) adding the aerosol generating agent and mixing (3) adding filler and mixing, and (4) adding tobacco extract and mixing thoroughly to form a smooth slurry.

In some embodiments, the slurry of aerosol generating material may be formed by a process comprising adding one or more additives, such as flavourants or colourants.

The slurry may be cast into a sheet on a casting plate or the band of a bandcasting machine. In some embodiments, the slurry may be cast so that the sheet has approximately even thickness or depth; a casting kni e may be used to ensure even thickness. In some embodiments, the cast sheet may have a thickness or depth of about 0.5-6 mm, 0.6-5 mm, 0.7-4 mm, 0.8-3 mm, 0.9-2.5 mm or 1-2 mm. In some embodiments, the slurry may be cast to have a thickness or depth of about 2 mm or of about 1 mm.

After being shaped, for example by casting or extruding, the slurry may be dried using any suitable method of drying. In some embodiments, the slurry may be dried at room temperature (i.e. about 20-25°C). In some embodiments, the slurry may be warmed to effect drying. In some embodiments, the slurry may be dried in warm air (i.e. an oven). In some embodiments, plate or band on which the wet slurry is resting may be warmed to effect drying. In embodiments where the slurry is warmed, the slurry may be dried at any suitable temperature for any suitable length of time. In some embodi ments, the slurry may be dried at a temperature of about 30-120°C, 70-110°C, 60-100°C, 40- 75^' r. 45-60 C or 45-55 C.

The cast sheet may be removed from the casting plate or band of the bandcasting machine by any suitable method. In some cases, the sheet and plate/band simply separate on application of a force. In some cases, the sheet may be removed using an item for accessing the space between structure and the plate, such as a knife or blade (a "doctoring knife"). Alternatively or in addition, the structure may be removed by increasing the temperature of the contact point between the structure and the plate. In some such embodiments, the structure may be removed from the plate using steam which, in addition to increasing the temperature of the contact point between the structure and the plate, causes sorption of water by the aerosol generating material which aids its removal.

In some embodiments, the sheet may be conditioned after being removed from the plate. In some embodi ments, the sheet may be conditioned at a temperature of about 20-25 ^'( ^', such as about 22 ( '. Alternatively or in addition, the component may be conditioned in air with a relative humidity of about 50-80%, such as about 60%. Commonly, conditioning is carried out at 22°C and a relative humidity of 60% for an appropriate time period, e.g. 48 hours.

In some embodiments, the component may then be stored (e.g. in a sealed container) at a temperature below room temperature (e.g. 4-20°C) and at any suitable humidity for any suitable length of time, before being incorporated into the device of the invention.

In some embodiments, the slurry may be cast, extruded or sprayed onto an electrically resistive heating element so that, on drying of the slurry, the electrically resistive heating element is at least partially embedded in the aerosol generating material.

The formed aerosol generating material may be rolled, cut, shredded, blended or subject to other processes before being formed into suitable consumables and, optionally, incorporated into devices of the present invention.

The invention will now be illustrated with reference to examples. These examples are for illustrative purposes only and do not limit the scope of the invention in any way.

Examples

"Solids" and "Solid(s) Content" refer to the whole of the extract or slurry other than the water, and may include components which by themselves are liquid at room temperature and pressure, such as glycerol.

The term "Wet Weight Basis" (WWB) refers to constituent concentration data calculated for material weights including water; "Dry Weight Basis" (DWB) refers to constituent concentration data for material weights corrected for water content. A weight quoted on a dry weight basis may include components which by themselves are liquid at room temperature and pressure, such as glycerol.

In the Examples, Reverse Osmosis [RO] quality water refers to softened which is additionally purified by reverse osmosis.

Example 1: Tobacco extraction and extract composition

Seven batches of whole leaf Buriey tobacco (4.5 kg per batch) were extracted with 80kg water (RO quality) at 60° C for 25 - 30 minutes with gentle agitation. The resulting mixture was filtered and centrifuged and the combined resulting extracts (480 1) were concentrated utilising an evaporative concentration process to 41.1% solids content (in this context, 'solids content' refers to the non-aqueous portion of the water extract). Table 1 shows the composition of the resulting tobacco extract.

Table 1 : Composition of tobacco extract.

The nicotine value refers to the absolute nicotine content of the aqueous tobacco extract (including water). [In other words, it is quoted on a wet weight basis. I

The density of the concentrated extract was 1.21 g/cm³.

After the process 9.12 kg of concentrated extract was obtained and stored at -18°C until required. Example 2: Aerosol generating material- manufacturing procedure and composition

Water (756g - reverse osmosis purified) was placed in a high shear mixer. Whi lst mixing, sodium alginate powder (15.01g) was slowly added, ensuring even mixing and full hydration to a smooth, viscous fluid. Glycerol (24.99g) was added to the high shear mixer with continuous mixing. Chalk (156.99g) was then added in a slow powder stream with continuous hi h shear mixing. Finally, tobacco extract (61.26g, prepared according to Example 1) was added with continuous hi h shear mixing until a smooth, free flowing slurry was formed.

After a smooth, free flowing slurry had been formed, the material was ready for casting into sheet.

The slurry was then cast onto a stainless steel casting plate at 2mm thickness using a casting knife. This provided a constant thickness of the slurry which was then dried. Drying can be effected by air drying at ambient conditions for approximately 24 hours or in an oven at about 45-55 °C for 0.5- 5 hours ( minimum time used to reduce loss of volatiles). The dried sheet was then removed from the plate and conditioned by exposure at 22 °C and 60% relative humidity (RH), for 48 hours. In some cases, the dried sheet was cut off the casting plate using a "doctoring" knife.

The resulting aerosol generating material was analysed for water, nicotine and glycerol content and the results are shown in Table 2.

Table 2: Analysis of the aerosol generating material.

Nicotine (ing/g) Glycerol (nig/g) Water (%)

6.7 (WWB) 90.3 (WWB )

6.3

7. 1 (DWB) 96.4 (DWB) Note: WWR: Wet Weight Basis (data calculated for material weights including water content); DWB: Dry Weight Basis (corrected for water content).

Example 3: Aerosol generation

Three samples of aerosol generating material, prepared according to Example 2, were heated in contact with an electrically resistive heating element. The resulting aerosol was analysed.

Table 3 indicates the aerosol composition that resulted in some of the experiments.

Table 3: Resulting aerosol compositions.

Table 4 below indicates the percentage transfer of nicotine and glycerol from the aerosol generating material to the aerosol following heating.

Table 4: Percentage transfer of selected substances to form aerosol.

Example 4: Tobacco extraction and extract composition

Seven batches of whole leaf Virginia tobacco (4.5 kg per batch) were extracted with 80kg water (RO quality) at 60° C for 25 - 30 minutes with gentle agitation. The resulting mixture was filtered and centrifuged and the combined resulting extracts (500 1) were concentrated utilising an evaporative concentration process to 49.6% solids content (in this context, 'solids content' refers to the non-aqueous portion of the water extract). Table 5 shows the composition of the resulting tobacco extract.

Table 5: Composition of tobacco extract.

The nicotine value refers to the absolute nicotine content of the aqueous tobacco extract (including water). [In other words, it is quoted on a wet weight basis.]

The density of the concentrated extract was 1 .25 g/cnr . After the process 11.68 kg of concentrated extract was obtained and stored at -18°C until required.

Examples 5-17

The aerosol generating materials of these examples were prepared by:

1. The alginate powder was mixed with glycerol.

2. The alginate- glycerol mixture was then added to water using a Silverson homogeniser at a high speed for ~8 minutes; the beaker was kept in an ice-box which was filled with ice chips (in order to keep the mixtures cool, which would have heated up due to high energy mixing).

3. Chalk was added into the alginate-glycerol- water mixture and mixed for -10 minutes, using a Silverson homogeniser at the same high speed.

4. Tobacco extract, prepared according to Example 4, was then added and the homogenisation carried out for -8-10 minutes, depending on the alginate type and concentration; the homogenisation speed was the same as in steps 2 and 3.

Overall, the total preparatory time was between 20 to 25 minutes.

The slurry compositions are shown below in Table 6.

Table 6: Slurry compositions.

* Tobacco extract weight is quoted on a wet weight basis (i.e. includes water content)

The slurries were cast onto metal plates to form 1mm thick sheets. The casted slurries were placed into an oven (Thermo Scientific Heraeus Oven) which was pre-set at 45 ( '. The slurries were dried into films, and when these were seen to be self-peeling off the plates, these were taken out of the oven and allowed to cool to room temperature. The sheets were then equilibrated in an oven (Binder unit ) which was pre-set at 20°C and 60% relative humidity for 48 hours.

Sheet constituent analysis

The water content of the equilibrated sheets was measured using the Karl Fischer technique. Approximately 5 g of a sample was accurately weighed into a dried 50 ml volumetric flask and filled to the mark with methanol. The sample and extraction solvent were mixed for 30 minutes and 5 ml of extraction solvent was then injected into the Karl Fischer equipment. Single extracts of the samples were taken with 3 measurements per extract carried out.

The equilibrated sheets were analysed for nicotine, propylene glycol and glycerol by GC-FID. For each sample, small pieces of the sheet were cut off for sample extraction. Approximately lg of sample was accurately weighed into a centrifuge tube and 20ml HPLC grade water added. The sample was macerated in the water for 2 minutes at 5000 rpm and subsequently filtered through a PTFE 0.45 Lim filter into a GC vial for GC-FID analysis. Each sample was prepared and analysed in duplicate.

The results are shown in Table 7 below.

Table 7: Water, nicotine and glycerol content of formed sheets.

The various embodiments described herein are presented only to assist in understanding and teaching the claimed features. These embodiments are provided as a representative sample of embodiments only, and are not exhaustive and/or exclusive. It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects described herein are not to be considered limitations on the scope of the invention as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the scope of the claimed invention. Various embodiments of the invention may suitably comprise, consist of, or consist essentially of, appropriate combinations of the disclosed elements, components, features, parts, steps, means, etc., other than those specifically described herein. In addition, this disclosure may include other inventions not presently claimed, but which may be claimed in future.

Claims

1. A solid aerosol generating material comprising;

about 5-35 wt% tobacco extract;

- about 50-80 wt% filler;

about 10-35 wt% aerosol generating agent; and about 2.5-10 wt% binder

wherein weight percentage is calculated on a dry weight basis.

2. An aerosol generating material according to claim 1 in the form of a sheet.

3. An aerosol generating material according to claim 1 or claim 2, wherein the filler is an organic material such as wood pulp, cellulose and cellulose derivatives, or wherein the filler is an inorganic material such as calcium carbonate, perlite, vermiculite, diatomaceous earth, colloidal silica, magnesium oxide, magnesium sulphate and magnesium carbonate.

4. An aerosol generating material according to claim 3, wherein the filler comprises chalk.

5. An aerosol generating material according to any preceding claim, wherein the aerosol generating agent comprises a polyol such as sorbitol, glycerol, and glycols like propylene glycol or triethylene glycol; a non-polyol such as monohydric alcohols, high boiling point hydrocarbons, acids such as lactic acid, glycerol derivatives, esters such as diacetin, triacetin, triethylene glycol diacetate, triethyl citrate or myristates including ethyl myristate and isopropyl myristate and aliphatic carboxylic acid esters such as methyl stearate, dimethyl dodecanedioate and dimethyl tetradecanedioate.

6. An aerosol generating material according to claim 5, wherein the aerosol generating agent comprises glycerol or propylene glycol.

7. An aerosol generating material according to any preceding claim, wherein the binder comprises alginate, polysaccharides, celluloses or modified celluloses, starches or modified starches, or natural gums.

8. An aerosol generating material according to claim 7, wherein the binder comprises an alginate such as sodium alginate, calcium alginate, potassium alginate or ammonium alginate.

9. An aerosol generating material according to any preceding claim, wherein the aerosol generating material is a cast material.

10. A component for aerosol generation by electrical heating, the component comprising an aerosol generating material according to any preceding claim and an electrically resistive heating element, wherein the electrically resistive heating element is at least partially embedded in the aerosol generating material.

11. A device for generating an inhaiable aerosol and/or gas, the device comprising an aerosol generating material according to any one of claim 1 to 9 and a heating means which volatilises components in use to form an aerosol and/or gas.

12. A device according to claim 11, wherein the heating means is an electrical heating means.

13. A device according to claim 12, wherein the electrical heating means is an electrically resistive heating element.

A device according to any one of claims 11 to 13, wherein the heating is at least partially embedded in the aerosol generating material.

15. A device according to any one of claims I I to 1 4, wherein the device is a tobacco heating product.

16. A method of making an aerosol generating material according to any one of claims 1 to 9 comprising the steps of;

(a) providing a slurry comprising the components of the aerosol generating material and water;

(b) casting, extruding or spraying the slurry; and

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

17. A method of making an aerosol generating material according to claim 16 further comprising the initial step of preparing a tobacco extract with a pi 1 that exceeds about 6.