WO2019086462A1

WO2019086462A1 - Sheet of a material containing alkaloids and method for producing the same

Info

Publication number: WO2019086462A1
Application number: PCT/EP2018/079720
Authority: WO
Inventors: Rui Nuno BATISTA; Antoine ZUEND
Original assignee: Philip Morris Products S.A.
Priority date: 2017-10-31
Filing date: 2018-10-30
Publication date: 2019-05-09

Abstract

The present invention relates to an aerosol generating article comprising a component including: - a material containing alkaloids, - a binder, - an aerosol-former, and - an encapsulated antisticking material, - wherein the encapsulated antisticking material comprises: - a core comprising an antisticking material, and - a shell comprising a shell-forming material surrounding the core.

Description

SHEET OF A MATERIAL CONTAINING ALKALOIDS AND METHOD

FOR PRODUCING THE SAME

The present invention is related to a method for producing a sheet of a material containing alkaloids, such as homogenized tobacco material, and including an encapsulated antisticking material.

Today, in the manufacture of tobacco products, besides tobacco leaves, also homogenized tobacco material is used. This homogenized tobacco material is tipically manufactured from parts of the tobacco plant that are less suited for the production of cut filler, like, for example, tobacco stems or tobacco dust. Typically, tobacco dust is created as a side product during the handling of the tobacco leaves during manufacture.

The starting material for the production of homogenized tobacco material for aerosol-generating article may also be mostly tobacco leaves that have thus the same size and physical properties as the tobacco for the blending of cut filler.

Possible forms of homogenized tobacco material include reconstituted tobacco sheet and cast leaf. The process to form homogenized tobacco material sheets commonly comprises a step in which ground tobacco and a binder are mixed to form a slurry. The slurry is then used to create a tobacco web or sheet, for example by casting a viscous slurry onto a moving metal belt to produce so called cast leaf. Alternatively, a slurry with low viscosity and high water content can be used to create reconstituted tobacco in a process that resembles paper-making.

The sheet or web of homogenized tobacco material is then rolled in bobbins which need to be unwound in order to be further processed and included in the aerosol-forming substrate of the aerosol-forming article.

Unwinding such bobbins can be however a difficult task. The homogenized tobacco material sheet, when coiled in bobbins, may be indeed difficult to unwind due to its consistency, sensitivity to heat, stickiness and low tensile strength : it could easily be torn apart and, if too high tensile strength is used to unwind the sheet, the sheet could break.

Furthermore, these bobbins may be difficult to transport and are furthermore currently consumed within a very short timeframe, since otherwise the windings of the sheet of homogenized tobacco materials bond together and this they quite definitively compromise unwinding. Consequently, building up a safety-stock of such bobbins can be a difficult task as well.

There is therefore a need of a sheet of material containing alkaloids, such as homogenized tobacco material, and method for producing the same, that is easily handled and transported, in particular when needed, and that therefore allows providing a continuous, constant and regular feed of material so that the rest of the production line can increase the overall production rate.

The invention may satisfy at least one of the above needs.

According to an aspect, the invention relates to an aerosol generating article comprising a component including : a material containing alkaloids, a binder, an aerosol -former, and an encapsulated antisticking material. The encapsulated antisticking material comprises: a core comprising an antisticking material, and a shell comprising a shell- forming material surrounding the core.

The component of the aerosol generating article is formed from a sheet. The sheet includes: a material containing alkaloids, and an encapsulated antisticking material. The encapsulated antisticking material comprises: a core comprising an antisticking material, and a shell comprising a shell-forming material surrounding the core.

The sheet comprises a material containing alkaloids and an encapsulated antisticking material. The antisticking material limits the stickiness of the sheet. The antisticking material is encapsulated, that is, it comprises a core including an antisticking material, and a shell surrounding the core. Therefore, depending on the properties of the material in which the shell is made, the antisticking material may exert a function or not. The resulting sheet including the encapsulated antisticking material may alter its properties depending on the availability of the antisticking material, such as it may be more or less "sticky".

As used herein, the term "sheet" denotes a laminar element having a length and length substantially greater than the thickness thereof. The width of a sheet is preferably greater than about 10 millimeters, more preferably greater than about 20 millimeters or about 30 millimeters. Even more preferably, the width of the sheet is comprised between about 100 millimeters and about 300 millimeters.

A "material containing alkaloids" is a material which contains one or more alkaloids. The alkaloids may comprise nicotine. The nicotine may be found, for example, in tobacco.

Alkaloids are a group of naturally occurring chemical compounds that mostly contain basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar structure are also termed alkaloids. In addition to carbon, hydrogen and nitrogen, alkaloids may also contain oxygen, sulfur and, more rarely, other elements such as chlorine, bromine, and phosphorus.

Alkaloids are produced by a large variety of organisms including bacteria, fungi, plants, and animals. They can be purified from crude extracts of these organisms by acid-base extraction. Caffeine, nicotine, theobromine, atropine, tubocurarine are examples of alkaloids.

As used herein, the term "homogenised tobacco material" denotes material formed by agglomerating particulate tobacco, which contains the alkaloid nicotine. The material containing alkaloids can thus be a homogenised tobacco material.

The most commonly used forms of homogenized tobacco material is reconstituted tobacco sheet and cast leaf. The process to form homogenized tobacco material sheets commonly comprises a step in which tobacco dust and a binder, are mixed to form a slurry. The slurry is then used to create a tobacco web. For example by casting a viscous slurry onto a moving metal belt to produce so called cast leaf. Alternatively, a slurry with low viscosity and high water content can be used to create reconstituted tobacco in a process that resembles paper- making.

The sheet material of tobacco can be referred to as a reconstituted sheet material and formed using particulate tobacco (for example, reconstituted tobacco) or a tobacco particulate blend, a humectant and an aqueous solvent to form the tobacco composition. This tobacco composition may then be casted, extruded, rolled or pressed to form a sheet material from the tobacco composition. The sheet of tobacco material can be formed utilizing a wet process, where tobacco fines are used to make a paper-like material; or a cast leaf process, where tobacco fines are mixed together with a binder material and cast onto a moving belt to form a sheet.

The sheet of homogenized tobacco material may be then rolled in bobbins which needs to be unwound in order to be further processed, to be part for example of an aerosol-forming article, that is to be included in the aerosol-forming substrate of the aerosol-forming article. In a "heat-not-burn" aerosol-generating article, an aerosol -forming substrate is heated to a relatively low temperature, in order to form an aerosol but prevent combustion of the tobacco material. Further, the tobacco present in the homogenized tobacco sheet is typically the only tobacco, or includes the majority of the tobacco, present in the homogenized tobacco material of such a "heat-not-burn" aerosol- generating article. This means that the aerosol composition that is generated by such a "heat-not-burn" aerosol-generating article is substantially only based on the homogenized tobacco material.

As used herein, the term "aerosol forming material" denotes a material that is capable of releasing volatile compounds upon heating to generate an aerosol. Tobacco, together with other compounds, may be classed as an aerosol forming material, particularly a sheet of homogenized tobacco comprising an aerosol former. An aerosol forming substrate may comprise or consist of an aerosol forming material.

The sheet containing alkaloids includes, in addition to the alkaloids containing material, such as tobacco, a binder and an aerosol -former, such as guar and glycerin. This composition leads to a sheet which may be "sticky", that is, it glues to adjacent objects, and at the same time it is rather fragile having a relatively low tensile strength.

Once a sheet of material containing alkaloids is produced, such as a sheet of homogenized tobacco material, it often needs to be stored at least for a certain time before it is further processed. In order to store it properly, without or with minimal risks of breakage or without occupying too much space, it is commonly wound into bobbins. However, winding the alkaloids containing sheet in a bobbin as such may create several problems in the subsequent unwinding, due to the "sticky" properties of the sheets. Due to the fact that the alkaloids containing sheet is sticky, the layers formed in the bobbin by the sheet wound in itself are prone to glue one onto the others, preventing unwinding.

In order to simplify the unwinding, or to anyhow produce a sheet of material which is relatively easy to handle, according to the invention a sheet of material containing alkaloids including an encapsulated antisticking material is provided.

In order to produce the sheet of material containing alkaloids including an encapsulated antisticking material, a sheet of material containing alkaloids is first provided. Commonly the sheet of material is formed, for example by extrusion or casting, from a slurry. An encapsulated antisticking material is applied to the sheet of material containing alkaloids.

The application of the encapsulated antisticking material can be performed according to any method. The encapsulated antisticking material may be sprayed, coated, brushed, on the sheet having a given second moisture content. The sheet itself may be immerged in the encapsulated antisticking material. The encapsulated antisticking material may be added as a further component to the slurry which is then preferably casted or extruded to form the sheet.

The term "antisticking material" means a material which acts to prevent adhesion. Therefore, it is less probable that something adheres on a surface threated with an antisticking material than on the same surface without the antisticking treatment. In other words, "antisticking material" defines a material that lowers the adhesion on a surface, with respect to the adhesion onto the same surface without the antisticking material.

The encapsulated material is commonly referred to as the core material . The encapsulation material is known as the shell . Thus the encapsulated antisticking material includes a core formed by the antisticking material itself. Around the core, the shell is positioned, to wrap the core as a membrane or coating.

The encapsulated antisticking material thus forms substantially a "particle". The core may vary greatly in size, shape and composition, as long as it includes the antisticking material. Further, the final encapsulated particle can be have an appearance that ranges from having regular, uniform shape through to being jagged and irregular.

Any technique may be used in the encapsulation of the core by the external shell. These techniques may include: fluid bed coating, wax and lipid coating, spray drying, spray congealing, hydrogel encapsulation, melt extrusion, or others.

Due to the encapsulation, the core material is protected and its release takes place when it is required.

For example, the antisticking material may have a timed release delivery. The shell coating material can be customized to determine the rate of delivery. Moreover, an encapsulated antisticking material may have an increasing shelf life and stability.

The antisticking material encapsulated form can be designed in a way that it degrades in a defined predictable way only under certain conditions, and therefore it releases its content only when such conditions are met. By way of example, an antisticking material in encapsulated form may comprise a shell material that is sensitive to temperature, or humidity. In this way, the antisticking material in encapsulated form may release its content when the environmental temperature, or humidity, is above a certain defined value. This can be particularly useful when adverse environmental conditions are present that may directly promote stickiness, and therefore avoiding or preventing such stickiness is desired.

An antisticking material in encapsulated form may comprise a shell material that is degradable in a certain defined predictable time, for example when exposed to the material containing alkaloids. In this way, the antisticking material in encapsulated form would release its content at a defined rate. This can be particularly useful in order to create a defined time delay effect of the release of the antisticking material independently of other factors, knowing that the stickiness problem only occurs after a certain time, and therefore releasing the antisticking material only when it is expected that the stickiness problem may occur. This delay may avoid or prevent potential problems of an early contact of the antisticking material with the material containing alkaloids, namely potential migration over time of the antisticking material to the interior of the material containing alkaloids, instead of remaining on its surfaces, and therefore causing inefficiencies in the antisticking effect on the surface of the material.

In this way an aerosol generating article with proper properties is obtained.

Preferably, the shell-forming material is selected from the group consisting of water soluble resins, water insoluble resins, waxes, enteric resins and mixtures thereof. The shell material, which is preferably formed in a degradable material, is preferably selected depending on the specific application and the specific antisticking material used as a core. For example, it may degrade with water (soluble shell).

More preferably, the water soluble resins are selected from the group consisting of gelatin, starch, polyvinylpyrrolidone, hydroxyethylcellulose and mixtures thereof.

More preferably, the water insoluble resins are selected from the group consisting of ethyl cellulose, polyethylene, polyamides, polymethacrylates and mixtures thereof.

More preferably, the waxes are selected from the group consisting of paraffins, beeswax, stearic acid, steryl alcohol and mixtures thereof.

More preferably, the enteric resins are selected from the group consisting of shellac, cellulose acetate phthalate, zein and mixtures thereof.

Preferably, the shell comprises a biodegradable polymer.

More preferably, the biodegradable polymer is selected from the group consisting of sodium alginate and sodium alginate compounds incorporating co-polymers such as sodium carboxy methyl cellulose (SCMC), methyl cellulose (MC), and/or poly vinyl pyrrolidone (PVP).

When the shell comprises a biodegradable polymer, the same may preferably degrade in a time comprised between about 36 hours to about 48 hours, at ISO standard room temperature and relative humidity, thus releasing the antisticking material in a defined time. Depending on the biodegradability characteristics of the shell, the release may preferably occur earlier when relative humidity is above 80 percent, namely releasing the antisticking material in about 6 to about 12 hours at such relative humidity conditions.

Preferably, the shell comprises a gumming agent. More preferably, the gumming agent is xanthan gum.

The fact that the shell comprises a gumming agent is advantageous as the same regulates the thickness, density and surface characteristics of the shell, leading to an encapsulated antisticking material comprising mainly spherical and free flowing encapsulated particles that are easy to handle and to use in the method of the invention.

Preferably, the shell comprises a cellulose material, more preferably methyl cellulose.

The fact that the shell comprises a cellulose material is particularly advantageous when the material containing alkaloids comprises cellulose fibers, due to the chemical compatibility of the same with the cellulose fibers, which may improve affinity of the encapsulated antisticking material to the material containing alkaloids.

Preferably, the antisticking material is selected from the group consisting of talc, sodium stearyl fumarate, sodium benzoate, magnesium stearate, tobacco powder or a mixture thereof.

Preferably, the antisticking material is selected from the group consisting of sodium starch, hydroxypropyl methylcellulose phthalate, glyceryl behenate, glyceryl monostearate, calcium stearate, ethyl cellulose cellulose acetate phthalate, ethyl acetate or a mixture thereof.

Preferably, the antisticking material is dimethicone.

The antisticking material and compounds are preferably selected among those listed and approved as additives for Food & Beverage and Pharma industries as neutral expedients additives, preferably also as inactive ingredients. Preferably the antisticking material can be applied in aqueous forms within several dilution ratios depending of the type of application. Even more preferably, the antisticking materials are selected among those which are cellulose based. Indeed, when the material containing alkaloids comprises cellulose fibers there is a natural compatibility of those ingredients in many ways, including chemical stability during, and after, drying.

Preferably, the sheet comprises: particles of the material containing alkaloids having a mean size comprised between about 0.03 millimetres and about 0.12 millimetres; a binder; and water.

In order to produce a slurry, the selected material containing alkaloids, such as the selected tobacco types, are to be ground in order to achieve a proper size, for example a size which is suitable for forming a slurry.

Preferably, the particles used in the slurry comprises particles of a material containing alkaloids, such as tobacco powder, having a mean size of between about 0.03 millimetres and about 0.12 millimetres. The mean size of between about 0.03 millimetres and about 0.12 millimetres represents the size at which the cells of the material may be at least in part destroyed. Moreover, the slurry obtained using the particles having this mean size is smooth and uniform.

Preferably, in order to minimize the energy used to obtain particles of the above mentioned size, the grinding phase is divided into two steps. For example, a coarse grinding step can be followed by a fine grinding step till the desired mean size of the particles is obtained. The coarse grinding step may comprise grinding material containing alkaloids strips into the smallest possible size while at the same time their cell structure remains substantially undamaged. Thus, the coarsely ground particles of the material containing alkaloids remain substantially dry. This is advantageous as the dry particles can be handled easily, for example for storing, blending and other subsequent processes. It has been found that, due to the inclusion of the coarse grinding step, the energy consumption in the further fine grinding step can be advantageously reduced by about 30 percent. This reduction in energy consumption in the fine grinding step is therefore available to increase the possible throughput through the fine grinding step when the energy consumption is kept at the same level as without the coarse grinding. Advantageously, this also allows decreasing the cost of production as less sophisticated machinery needs to be utilized to manufacture the coarse ground tobacco particles than is required for the manufacture of fine ground tobacco powder.

Therefore, in a preferred step the material containing alkaloids is coarse grinded, that is, it is reduced to a particle size in which the cells are on average not broken or destroyed. Advantageously, at this stage, the resulting coarse ground material containing alkaloids stays dry, such that any viscous or sticky behaviour of the resulting coarse ground material containing alkaloids is avoided. After this first coarse grinding, in an additional grinding step the material containing alkaloids is preferably ground into a powder with a mean particle size which is suitable for the formation of a slurry. In this second grinding step, the cells of the material containing alkaloids may be to some extent or completely destroyed.

By reducing the powder mean size, less binder may be required to form the sheets described herein. It is also believed that by fine grinding the material containing alkaloids to a finer powder size, substances within the cells can be released in a relatively easy manner, such as for example - in case of tobacco - pectin, nicotine, essential oils and other flavours.

Preferably, the step of coarse grinding according to the invention comprises coarse grinding said material containing alkaloids, for example tobacco leaves, to obtain particles of a mean size of between about 0.25 millimetres and about 2.0 millimetres, more preferably, a mean size of between about 0.3 millimetres and about 1.0 millimetres and most preferably, a mean size of between about 0.3 millimetres and about 0.6 millimetres. At the size of between about 0.25 millimetres and about 2 millimetres, the cells of the material containing alkaloids are still substantially intact such that the handling of the coarse ground material containing alkaloids is relatively easy.

These particles of the material containing alkaloids are preferably added together with a binder and an antisticking material in order to form a slurry.

The addition of the encapsulated antisticking material allows creating a final product, such as a sheet, which has a reduced thickness, so that bobbins formed by the sheet are more easily handled and unwind. A sheet formed by a slurry including an anti-sticking material is less "sticky" than a sheet which includes only the material including alkaloids and the binder. In particular, the relatively small sizes of the particles of the material containing alkaloids which are included in the slurry may render the latter particularly sticky when cast.

Due to the facilitated handling of the sheet, production speed may be increased.

Preferably, said material containing alkaloids is included in an amount from about 45 percent and about 93 percent in dry weight basis in the sheet.

The material containing alkaloids, such as tobacco, is the main component of the sheet.

Preferably, said material containing alkaloids is a tobacco material.

Preferably, the sheet comprises a coating layer of the encapsulated antisticking material. Forming a coating layer is a relatively easy and reliable process that can be performed fast and therefore it is suitable for the speed required in the manufacturing of aerosol-generating articles.

Preferably, the coating layer of the encapsulated antisticking material has a thickness comprised between about 5 micron and about 20 micron. More preferably, the coating layer of the encapsulated antisticking material has a thickness comprised between about 5 micron and about 15 micron.

The thickness of the coating layer of the encapsulated antisticking material depends on the minimum layer for which an antisticking effect is achieved and on the desired overall thickness of the sheet. The overall thickness of the sheet may influence the smoking experience of the user and therefore it may be a relevant factor. Further, the thickness of the coating layer of the encapsulated antisticking material may depends on the speed of the sheet during for example casting, because it influences the speed of the devices used to realize the coating layer.

Preferably, said encapsulated antisticking material is in nano- encapsulated or micro-encapsulated form.

Nanoencapsulation is the coating of various substances within another material at sizes on the nano-scale. Microencapsulation is similar to nanoencapsulation aside from it involving larger particles.

Preferably, the total size of the particles of encapsulated antisticking material is from about 5 to about 10 micron.

Preferably, in the encapsulated antisticking material the ratio between the volume of the shell and the volume of the core is comprised between about 1 : 3 to about 1 : 9.

The invention relates to a method for producing an aerosol generating article including an encapsulated antisticking material, the method comprising the steps of: providing a sheet including a material containing alkaloids, a binder and an aerosol -former; applying to the sheet an encapsulated antisticking material including a core comprising an antisticking material and a shell comprising a shell-forming material surrounding the core; cutting the sheet to form components; and including at least a component into the aerosol generating article.

The invention also relates to a method for producing a sheet including an encapsulated antisticking material, the method comprising the steps of: providing a sheet including a material containing alkaloids; and applying to the sheet an encapsulated antisticking material including a core comprising an antisticking material and a shell comprising a shell- forming material surrounding the core.

The advantages of this aspect have been already outlined with reference to the first aspect and are not repeated herewith.

Preferably, the shell-forming material is selected from the group consisting of water soluble resins, water insoluble resins, waxes, enteric resins and mixtures thereof to the sheet including a material containing alkaloids.

More preferably, the method comprises drying the sheet including a material containing alkaloids and an encapsulated antisticking material.

A web of material containing alkaloids is preferably formed by a casting process of the type generally comprising casting a slurry prepared including the blend of tobacco powder above described on a support surface. Preferably, the cast web is then dried to form a web of homogenized material containing alkaloids and it is then removed from the support surface.

Preferably, the moisture of said cast material containing alkaloids web at casting is between about 60 percent and about 80 percent of the total weight of the tobacco material at casting. Preferably, the method for production of a homogenized material containing alkaloids comprises the step of drying said cast web, winding said cast web, wherein the moisture of said cast web at winding is between about 7 percent and about 15 percent of dry weight of the material containing alkaloids web. Preferably, the moisture of said homogenized tobacco web at winding is between about 8 percent and about 12 percent of dry weight of the homogenized material containing alkaloids web.

Preferably, said sheet including a material containing alkaloids has a first free surface and a second free surface and said step of applying an encapsulated antisticking material comprises applying the encapsulated antisticking material on at least one of the first and second free surface of the sheet including a material containing alkaloids.

More preferably, the step of applying an encapsulated antisticking material on at least one of the first and second free surface of the sheet including a material containing alkaloids comprises applying an encapsulated antisticking material on both first and second free surface of the sheet including a material containing alkaloids.

The first and second application of the encapsulated antisticking material may respectively and independently render the whole first and the whole second free surface of the sheet or only a portion thereof non- sticky. Each or both of application may also respectively be applied only on selected areas of the first and second free surfaces.

In this way, the multilayer sheet including a material containing alkaloids has at least two "not-sticky" free surfaces and may therefore be wound up to form a bobbin without or with minimal risks of breakage during unwinding of the same.

Preferably, the sheet including a material containing alkaloids has a first free surface and a second free surface and the step of applying an encapsulated antisticking material comprises depositing a coating layer including an encapsulated antisticking material on the first or on the second free surface.

As used herein, the term "coating" denotes a covering that is applied to the surface of an object. The coating may be an all-over coating, completely covering the substrate, in this case the free surface of the sheet onto which it is applied, or it may only cover parts of the same.

If the resulting multilayer sheet is coiled into a bobbin, the first coating layers including the antisticking material or the second coating layer including the antisticking material are in contact with each other and therefore the possibility that they "glue" together is rather limited. In this way, the multilayer sheet may be wound into a bobbin comprising a plurality of windings of a multilayer sheet including a material containing alkaloids that do not stick together and may therefore be easily unwound. Preferably, the coating layer including an encapsulated antisticking material has a thickness comprised between about 5 micron and about 20 micron. More preferably, the coating layer including an encapsulated antisticking material has a thickness comprised between about 5 micron and about 15 micron.

Aerosol generating articles, also called aerosol forming articles, according to the present invention may be in the form of filter cigarettes or other smoking articles in which tobacco material is combusted to form smoke. The present invention additionally encompasses articles in which tobacco material is heated to form an aerosol, rather than combusted, and articles in which a nicotine-containing aerosol is generated from a tobacco material without combustion or heating.

Aerosol forming articles according to the invention may be whole, assembled aerosol forming articles or components of aerosol forming articles that are combined with one or more other components in order to provide an assembled article for producing an aerosol, such as for example, the consumable part of a heated smoking device.

An aerosol forming article may be an article that generates an aerosol that is directly inhalable into a user's lungs through the user's mouth. An aerosol forming article may resemble a conventional smoking article, such as a cigarette and may comprise tobacco. An aerosol forming article may be disposable. An aerosol forming article may alternatively be partially-reusable and comprise a replenishable or replaceable aerosol forming substrate.

An aerosol forming article may also include a combustible cigarette. In preferred embodiments, the aerosol forming- article may be substantially cylindrical in shape. The aerosol forming article may be substantially elongated. The aerosol forming article may have a length and a circumference substantially perpendicular to the length. The aerosol forming article may have a total length between approximately about 30 millimeters and approximately about 100 millimeters. The aerosol forming article may have an external diameter between approximately about 5 millimeters and approximately about 12 millimeters.

In all the aspects of the invention, preferably, the sheet including a material containing alkaloids is a homogenized tobacco sheet, where the material containing alkaloids is tobacco containing nicotine.

Preferably, the homogenized tobacco sheet is obtained casting a slurry.

The homogenized tobacco sheet includes tobacco particles grinded from tobacco leaves (for example tobacco stem and lamina).

The homogenized tobacco sheet may also comprise a minor quantity of one or more of tobacco dust, tobacco fines, and other particulate tobacco by-products formed during the treating, handling and shipping of tobacco.

The tobacco present in the homogenized tobacco material may constitute the majority of the tobacco, or even substantially the total amount of tobacco present in the aerosol-generating article. The impact on the characteristics of the aerosol, such as its flavour, may derive predominantly from the homogenized tobacco material. It is preferred that the release of substances from the tobacco present in the homogenized tobacco material is simplified, in order to optimize use of tobacco. In the following, the term "tobacco particles" is used through the specification to indicate tobacco having a mean size per weight between about 0.03 millimetres and about 0.12 millimetres.

Tobacco particles having a mean particle size by weight between about 0.03 millimetres and about 0.12 millimetres may improve the homogeneity of the slurry. The quantity of binder added to the blend of one or more tobacco types is comprised between about 1 percent and about 5 percent in dry weight of the slurry. The binder used in the slurry may be any of the gums or pectins described herein. The binder may ensure that the tobacco powder remains substantially dispersed throughout the homogenized tobacco web. For a descriptive review of gums, see Gums And Stabilizers For The Food Industry, IRL Press (G.O. Phillip et al. eds. 1988); Whistler, Industrial Gums: Polysaccharides And Their Derivatives, Academic Press (2d ed. 1973); and Lawrence, Natural Gums For Edible Purposes, Noyes Data Corp. (1976).

The homogenized tobacco material comprises preferably between about 45 percent and about 93 percent in dry weight basis of tobacco particles.

Preferably, the homogenized tobacco sheet also includes a binder.

Although any binder may be employed, preferred binders are natural pectins, such as fruit, citrus or tobacco pectins; guar gums, such as hydroxyethyl guar and hydroxypropyl guar; locust bean gums, such as hydroxyethyl and hydroxypropyl locust bean gum; alginate; starches, such as modified or derivitized starches; celluloses, such as methyl, ethyl, ethylhydroxymethyl and carboxymethyl cellulose; tamarind gum; dextran; pullalon; konjac flour; xanthan gum and the like. The particularly preferred binder for use in the present invention is guar.

Preferably, binder is in an amount comprised between about 1 percent and about 5 percent in dry weight basis of the homogenized tobacco sheet. More preferably, it is comprised between about 2 percent and about 4 percent.

Preferably, the homogenized tobacco sheet also includes cellulose fibers, in addition to the cellulose fibers already present in the tobacco.

Cellulose fibres may be introduced in the slurry. The introduction of cellulose fibres in the slurry typically increases the tensile strength of the tobacco material web, acting as a strengthening agent. Therefore, adding cellulose fibres may increase the resilience of the homogenized tobacco material web.

Cellulose fibres for including in a slurry for homogenized tobacco material are known in the art and include, but are not limited to: softwood fibres, hard wood fibres, jute fibres, flax fibres, tobacco fibres and combination thereof. In addition to pulping, the cellulose fibres might be subjected to suitable processes such as refining, mechanical pulping, chemical pulping, bleaching, sulphate pulping and combination thereof.

Cellulose fibres may include tobacco stem materials, stalks or other tobacco plant material. Preferably, cellulose fibres such as wood fibres comprise a low lignin content. Alternatively fibres, such as vegetable fibres, may be used either with the above fibres or in the alternative, including hemp and bamboo.

The length of cellulose fibres is advantageously between about 0.2 millimetres and about 4 millimetres. Preferably, the mean length per weight of the cellulose fibres is between about 1 millimetre and about 3 millimetres.

Further, preferably, the amount of the cellulose fibres is comprised between about 1 percent and about 7 percent in dry weight basis of the total weight of the slurry (or homogenized tobacco sheet).

Advantageously, the method comprises the step of adding an aerosol- former to the slurry. Suitable aerosol -formers for inclusion in slurry for homogenised tobacco material are known in the art and include, but are not limited to: monohydric alcohols like menthol, polyhydric alcohols, such as triethylene glycol, 1,3-butanediol and glycerin; esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate. Examples of preferred aerosol -formers are glycerin and propylene glycol.

The homogenized tobacco material may have an aerosol-former content of greater than about 5 percent on a dry weight basis. The homogenized tobacco material may alternatively have an aerosol former content of between about 5 percent and about 30 percent by weight on a dry weight basis. More preferably, the aerosol -former is comprised between about 10 percent to about 25 percent of dry weight of the homogenized tobacco material. More preferably, the aerosol-former is comprised between about 15 percent to about 25 percent of dry weight of the homogenized tobacco material.

The binder and the cellulose fibers are preferably included in a weight ratio comprised between about 1 : 7 and about 5 : 1. More preferably, the binder and the cellulose fibers are included in a weight ratio comprised between about 1 : 1 and about 3 : 1.

The binder and the aerosol-former are preferably included in a weight ratio comprised between about 1 : 30 and about 1 : 1. More preferably, the binder and the aerosol -former are included in a weight ratio comprised between about 1 : 20 and about 1 :4.

The binder and the tobacco particles are preferably included in a weight ratio comprised between about 1 : 100 and about 1 : 10. More preferably, the binder and the tobacco particles are included in a weight ratio comprised between about 1 : 50 and about 1 : 15, even more preferably between about 1 : 30 and 1 : 20.

The aerosol -former and the tobacco particles are preferably included in a weight ratio comprised between about 1 : 20 and about 1 : 1. More preferably, the aerosol-former and the tobacco particles are included in a weight ratio comprised between about 1 :6 and about 1 : 2. The aerosol former and the cellulose fibres are preferably included in a weight ratio comprised between about 1 : 1 and about 30: 1. More preferably, the aerosol -former and the cellulose fibres are included in a weight ratio comprised between about 5 : 1 and about 15 : 1.

The cellulose fibres and the tobacco particles are preferably included in a weight ratio comprised between about 1 : 100 and about 1 : 10. More preferably, the cellulose fibres and the tobacco particles are preferably included in a weight ratio comprised between about 1 : 50 and about 1 : 20.

The above mentioned weight ratios of the ingredients of the homogenized tobacco sheet are applicable not only to the homogenized tobacco sheet, but also they are the weight ratios of the various ingredients present in the slurry.

A web of homogenized tobacco material is preferably formed by a casting process of the type generally comprising casting a tobacco slurry onto a moving metal belt. Preferably, the cast web is dried to form a web of homogenized tobacco material and it is then removed from the support surface.

Specific embodiments of the invention will be further described, by way of example only, with reference to the accompanying drawings in which:

• Figure 1 shows a flow diagram of the method of the invention to produce a multilayer coated sheet including an antisticking material;

• Figure 2 is a lateral perspective view of a multilayer coated sheet of the invention; and

• Figure 3 is a lateral schematic view of an apparatus for carrying out the method of the invention to produce a multilayer coated sheet of the invention. With initial reference to Figure 1 and 2, a method for the production of a multilayer coated sheet 200 (visible in figure 2) of the invention is represented. The first step 100 of the method of the invention is the provision of a sheet 210 of a material containing alkaloids having a first free surface and a second free surface. Material containing alkaloids to be used in the method of the invention preferably is a homogenized tobacco material. Preferably, in step 100 the homogenized tobacco sheet 210 has a thickness of between about 100 micron and about 300 micron and a width from between about 0.1 meters to about 2 meters.

The method includes a further step 101 in which a first coating layer 220 of a first antisticking material is applied on the first free surface of the sheet 210 of a material containing alkaloids. Preferably, the thickness of said first coating layer 220 is comprised between about 5 micron and about 20 micron.

The antisticking m aterial is a micro-encapsulated antisticking material.

Further, the method of the invention may include a step 102 of applying a second coating layer 230 of a second antisticking material on the second free surface of the sheet 210 of a material containing alkaloids. Preferably, the thickness of said second coating layer 230 is comprised between about 5 micron and about 20 micron.

In this way, at the end of step 102 a multilayer coated sheet 200 of a material containing alkaloids comprising a layer 210 of a material containing alkaloids, a first coating layer 220 of a first antisticking material and a second coating layer 230 of a second antisticking material is obtained.

In Fig. 2, a lateral perspective view of the multilayer coated sheet 200 realized according to the method of the invention is shown. In Fig. 3, a lateral schematic view of an apparatus 300 for carrying out the method of the invention to produce a multilayer coated sheet 200 from the sheet 210 of a material containing alkaloids is shown. Sheet 210 defines a free surface 305 and a second surface 306.

Preferably, but not necessarily, the apparatus 300 puts in operation the method of the invention described with reference to figure 1.

In Fig. 3, the apparatus 300 includes a conveyor belt 302 and an applying device 304.

Conveyor belt 302 moves the sheet 210 of a material containing alkaloids along a transport direction (indicated by arrow 303) towards applying device 304.

Material containing alkaloids to be used in the method of the invention preferably includes a homogenized tobacco material . Sheet 210 is preferably a homogenized tobacco material sheet having a thickness of between about 100 micron and about 300 micron and a width from between about 0.1 meters to about 2 meters.

Applying device 304 includes two coating devices 307 and 308. Coating devices 307 applies to first free surface 305 a coating layer 220 having a thickness of about 7 micron of a first antisticking material.

Coating device 308 applies to second free surface 306 a coating layer 230 having a thickness of about 7 micron of a second antisticking material.

The antisticking materials applied by coating devices 307 and 308 are different each other, or they may be the same. In both cases, the antisticking material is a micro-encapsulated antisticking material.

Downstream of coating devices 307 and 308, the multilayer coated sheet 200 comprising the layer (sheet) 210 of a material containing alkaloids, the first coating layer 220 of a first antisticking material and the second coating layer 230 of a second antisticking material is obtained, which may be directed by roller 310 to further downstream processing steps.

Claims

Aerosol generating article comprising a component including :

- a material containing alkaloids,

- a binder,

- an aerosol -former, and

- an encapsulated antisticking material,

- wherein the encapsulated antisticking material comprises:

o a core comprising an antisticking material, and o a shell comprising a shell-forming material surrounding the core.

Aerosol generating article according to claim 1, wherein the shell-forming material is selected from the group consisting of water soluble resins, water insoluble resins, waxes, enteric resins and mixtures thereof.

Aerosol generating articleaccording to claim 2, wherein the water soluble resins are selected from the group consisting of gelatin, starch, polyvinylpyrrolidone, hydroxyethylcellulose and mixtures thereof.

Aerosol generating articleaccording to claim 2, wherein the water insoluble resins are selected from the group consisting of ethyl cellulose, polyethylene, polyamides, polymethacrylates and mixtures thereof.

Aerosol generating article according to claim 2, wherein the waxes are selected from the group consisting of paraffins, beeswax, stearic acid, steryl alcohol and mixtures thereof. Aerosol generating article according to claim 2, wherein the enteric resins are selected from the group consisting of shellac, cellulose acetate phthalate, zein and mixtures thereof.

Aerosol generating article according to any of the preceding claims, wherein the antisticking material is selected from the group consisting of talc, sodium stearyl fumarate, sodium benzoate, magnesium stearate, tobacco powder,sodium starch, hydroxypropyl methylcellulose phthalate, glyceryl behenate, glyceryl monostearate, calcium stearate, ethyl cellulose, cellulose acetate phthalate, ethyl acetate, dimethicone or a mixture thereof.

Aerosol generating article according to any of the preceding claims comprising :

- particles of the material containing alkaloids having a mean size comprised between about 0.03 millimetres and about 0.12 millimetres; and

- water.

Aerosol generating article according to any of the preceding claims, wherein said material containing alkaloids is included in an amount from about 45 percent and about 93 percent in dry weight basis in the sheet.

Aerosol generating article according to any one of the preceding claims, wherein said material containing alkaloids is a tobacco material.

Aerosol generating article according to any one of the preceding claims, wherein said encapsulated antisticking material is in nano-encapsulated or micro-encapsulated form.

Method for producing an aerosol generating article including an encapsulated antisticking material, the method comprising the steps of:

- providing a sheet including a material containing alkaloids, a binder and an aerosol -former;

- applying to the sheet an encapsulated antisticking material including a core comprising an antisticking material and a shell comprising a shell-forming material surrounding the core;

- cutting the sheet to form components; and

- including at least a component into the aerosol generating article.

13. The method according to claim 12, wherein the shell-forming material is selected from the group consisting of water soluble resins, water insoluble resins, waxes, enteric resins and mixtures thereof to the sheet including a material containing alkaloids.

14. Method according to claim 12 or 13, comprising the step of:

- drying the sheet including a material containing alkaloids and the encapsulated antisticking material.

15. Method according to any of claims 12 - 14, wherein said sheet including a material containing alkaloids has a first free surface and a second free surface and said step of applying an encapsulated antisticking material comprises applying the encapsulated antisticking material on at least one of the first and second free surface of the sheet including a material containing alkaloids.

16. Method according to claim 15, wherein the step of applying an encapsulated antisticking material on at least one of the first and second free surface of the sheet including a material containing alkaloids comprises applying an encapsulated antisticking material on both first and second free surface of the sheet including a material containing alkaloids.

17. Method according to any one of claims 12 to 16, wherein the sheet including a material containing alkaloids has a first free surface and a second free surface and wherein the step of applying an encapsulated antisticking material comprises depositing a coating layer including an encapsulated antisticking material on the first or on the second free surface.

18. Method according to claim 17, wherein the coating layer including an encapsulated antisticking material has a thickness comprised between about 5 micron and about 20 micron.

19. Method according to any one of claims 12 to 18 when dependent on claim 13, wherein the water soluble resins are selected from the group consisting of gelatin, starch, polyvinylpyrrolidone, hydroxyethylcellulose and mixtures thereof.

20. Method according to any one of claims 12 to 19 when dependent on claim 13, wherein the water insoluble resins are selected from the group consisting of ethyl cellulose, polyethylene, polyamides, polymethacrylates and mixtures thereof.

21. Method according to any one of claims 12 to 20 when dependent on claim 13, wherein the waxes are selected from the group consisting of paraffins, beeswax, stearic acid, steryl alcohol and mixtures thereof.

22. Method according to any one of claims 12 to 21 when dependent on claim 13, wherein the enteric resins are selected from the group consisting of shellac, cellulose acetate phthalate, zein and mixtures thereof.

23. Method according to any one of claims 12 to 22, wherein the antisticking material is selected from the group consisting of talc, sodium stearyl fumarate, sodium benzoate, magnesium stearate, tobacco powder,sodium starch, hydroxypropyl methylcellulose phthalate, glyceryl behenate, glyceryl monostearate, calcium stearate, ethyl cellulose, cellulose acetate phthalate, ethyl acetate, dimethicone or a mixture thereof.

24. Method according to any one of claims 12 to 23, wherein the sheet comprises:

- particles of a material containing alkaloids having a mean size comprised between about 0.03 millimetres and about 0.12 millimetres; and

- water.

25. Method according to claim 24, wherein said sheet comprises from about 45 percent and about 93 percent in dry weight basis of the particles of a material containing alkaloids.

26. Method according to any one of claims 12 to 25, wherein said material containing alkaloids is a tobacco material.