Patent Publication Number: US-2023137057-A1

Title: Randomly-Oriented Fibre Tobacco Mousse Consumables

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to the field of tobacco, especially tobacco-containing foam-like or mousse-like aerosol-generating material for use in a heat-not-burn vaping device or an oven-type vaping device. 
     BACKGROUND OF THE INVENTION 
     Aerosol-generating articles comprising aerosol-generating material used in a heat-not-burn (HnB) vaping device have been known since 1980. It is nonetheless only becoming more popular since the turn of the 21 st  century, as studies have shown that HnB vapour releases significantly less of most of the chemicals in tobacco smoke. Moreover, none of the combustion emission process occurs when the HnB smoking articles are used in the HnB holder. Hence, it is generally agreed that the aerosol generated is not smoke, and thus such a smoking consumables could be better known as an aerosol-generating consumables or an aerosol-generating article. 
     Patent document DE 102013220758 relates to a method for producing rod-shaped articles of the tobacco processing industry, in which a tobacco fibre cake is first shaken up in a suction strand conveyor. Further, tobacco fibres are applied to the tobacco fibre cake and the portions of the solid material to form a strand. The invention nevertheless fails to address the vapour performance of the smoking article. 
     Although there exist different shapes and sizes of HnB aerosol-generating articles in the market, consumers at the same time acknowledge that they do not offer a comparable taste and sensory experience to conventional smoking articles such as cigarettes or cigars. In particular, consumers find currently available products to lack real tobacco taste. 
     It would thus be advantageous to provide consumers with aerosol-generating articles and materials providing a more pleasant taste experience to consumers where consumables mimic closer to real tobacco. 
     SUMMARY OF THE INVENTION 
     The inventors of the present invention have found solutions to the above-discussed problems through a new and inventive aerosol-generating article as defined in the claims. 
     A first aspect of the invention relates to an aerosol-generating material, comprising a mixed arrangement of randomly-oriented fibres and an aerosol-generating substrate in a semi-solid state such as a foam or a paste. 
     A second aspect of the invention relates to an aerosol-generating article comprising the aerosol-generating material of the present invention. 
     A third aspect of the invention relates to a method of manufacturing an aerosol-generating material of the present invention, comprising the steps of: 
     a. Providing a semi-solid aerosol-generating substrate; 
     b. Providing randomly-oriented fibres to the aerosol-generating substrate, to form an arrangement of randomly-oriented tobacco-containing substrate-coated fibres; 
     c. Drying said randomly-oriented substrate-coated fibres. 
     A fourth aspect of the invention relates to a method of manufacturing an aerosol-generating article according to the present invention, comprising the steps of: 
     a. Providing an aerosol-generating material according to the present invention to one or more surfaces of a support element by spraying, filling, dipping, bathing, coating or extruding; and 
     b. Drying the aerosol-generating material applied to the support element. 
     A fifth aspect of the invention relates to the use of the aerosol-generating material according to the present invention or an aerosol-generating article according to the present invention in a heat-not-burn vaping device or in an oven-type vaping device. 
     The inventors of the present invention found out that the aerosol-generating material and the aerosol-generating article of the present invention has better vapour performance due to the fact that the aerosol-generating material which comprises randomly oriented fibre can be heated more evenly and easily, as more surface area of the fibre material is in direct contact with air, thereby the article can be heated more efficiently for the release of vapour/aerosol. Moreover, also thanks to the fact that the aerosol-generating material comprises very short fibres which may be in form of a strand is also particularly suitable to be provided into a secondary structure, such as a 3-dimensional object. 
     According to one embodiment, the fibres are coated with the aerosol-generating substrate. This allows the substrate which is applied on the fibre to release the aerosol more easily as more surface area (as well as the nature of the substrate itself) of the aerosol-generating material are in contact with heated air. The aerosol-generating substrate may be for instance tobacco-containing aerosol-generating substrate, wherein the substrate may be provided in powdery form, or provided into a powdery-foam mixture of a semi-solid state. 
     According to some preferred embodiments, the fibres are formed from aerosol-generating substrate. This embodiment allows higher amount of aerosol to be released as higher volume of the aerosol-generating substrate are being compacted to form the aerosol-generating material. 
     In some embodiments, the fibres have a length of less than 5.0 mm, preferably between 0.2 mm to 3.5 mm, more preferably between 0.5 mm and 2.0 mm. This very short length of fibre gives the aerosol-generating material a unique physical property, as this very short length of fibre give good vapour performance when being heated. 
     In other embodiments, the fibres are provided to the surface of the aerosol-generating substrate or are mixed with the aerosol-generating substrate. The fibres can for instance be dipped into a pool aerosol-generating substrate through the surface of the pool or bath of the aerosol-generating substrate. 
     In some further embodiments, the aerosol-generating substrate is adhered to the fibres through a binder or a glue, or without any assistance of the glue or binder. One or more binders or glues can be mixed with the aerosol-generating substrate to enhance the capacity of the substrate to be adhered to other surfaces i.e. the fibres or any carrier elements. 
     According to some preferred embodiments, the aerosol-generating material is adhered to one or more of the surfaces of a support element. The aerosol-generating material which comprise fibres, aerosol-generating substrate and/or other compositions is capable of adhering itself to the surfaces of a support element or a carrier element. The texture and consistency of the aerosol-generating substrate which is in semi-solid state provides 
     According to some preferred embodiments, the support element is a frame, a woven or a non-woven fabric, a backing material and/or a sheet. 
     In some particularly preferred embodiments, the method further comprises one or more of the following steps: 
     a. Providing a binder or a glue to the fibres; 
     b. Providing the fibres to the aerosol-generating substrate by mixing, spraying, dipping, bathing or coating. 
     In some other embodiments, it further comprises a step of removing the support element from the aerosol-generating material after drying. A final version of aerosol-generating article (or material) is thus shaped thanks the support element which serves as a mould. 
     In some further embodiments, it further comprises a step of forming the aerosol-generating material into a determined shape by molding, cutting, folding, rolling or stamping. 
     By “about” or “approximately” in relation to a given numerical value, it is meant to include numerical values within  10 % of the specified value. All values given in the present disclosure are to be understood to be complemented by the word “about”, unless it is clear to the contrary from the context. 
     The indefinite article “a” or “an” does not exclude a plurality, thus should be treated broadly. 
     The term “comprise” as used herein can be replaceable with “is” when only one element is described or can be replaceable with “are” when more than one elements are described. 
     Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. 
     Any reference to the “cross section profile” of the aerosol-generating consumable article or a component of the aerosol-generating article refers to the transverse cross-section unless stated otherwise. 
     A “tobacco-containing” can be any compound, mixture, particle matter, and/or solution that contains and/or carries a constituent of tobacco, either artificially included or naturally contained in tobacco, e.g. tobacco, tobacco particles, tobacco flavor and/or nicotine. In contrast, an example for an artificially added non-tobacco specific flavor would be menthol. 
     As used herein, the term “aerosol-generating article” refers to an aerosol-generating article for producing an aerosol comprising an aerosol-generating material that is intended to be heated rather than com busted in order to release volatile compounds that can form an aerosol. The consumable article can be heated in an oven-type or an internal heating type of vaping device. 
     As used herein, the term “aerosol-generating material” refers to a material capable of releasing upon heating volatile compounds, which can form an aerosol. The aerosol generated from aerosol-generating material of aerosol-generating articles described herein may be visible or invisible and may include vapours (for example, fine particles of substances, which are in a gaseous state, that are ordinarily liquid or solid at room temperature) as well as gases and liquid droplets of condensed vapours. The “aerosol-generating material” as used herein is a final version and is ready to be used for the manufacturing of the aerosol-generating article. The aerosol-generating material may comprise for instance fibres, aerosol-generating substrate, binder, water, humectant and etc. 
     As used herein, the term “aerosol-generating substrate” refers to a substance which is capable of releasing aerosol and/or vapour. The aerosol-generating substrate can for example be made up of tobacco-containing material which is provided in fine particles or in a powdery form, and/or may comprise other aerosol-forming/stabilizing material such as propylene glycol and glycerine such that the aerosol-generating substrate can be provided in a semi-solid state such as foam or mousse. 
     The term “semi-solid state” as used herein refers strictly to non-solid and non-liquid condition. In the broadest definition, the semi-solid state according to the present invention includes gel, cream, foam, slurry, mud or mousse. In the strictest definition, the semi-solid state according to the present invention refers to foam or mousse. 
     The term “randomly-oriented fibre” as used herein refers to a state where the fibres are not arranged, not aligned, and has not been pressed or compacted. The fibres are loosely positioned and spaced from each other, and hence are preferably single stranded fibres. The randomly-oriented fibres could for example obtained from reconstituted tobacco material which is subjected to shredding and filtered through sieving. The fibres are spaced and positioned through free-flowing for instance. 
     An aerosol-forming agent can be any compound, mixture and/or solution that is capable of forming an aerosol, e.g. when heated, mixed, blended, aerated and/or in mixture with a tobacco ingredient containing agent. Well known examples include humectants such as glycerin and propylene glycol, other alcohols, such as ethanol, etc. 
     As used herein, wt.-% is to be understood as weight percent, based on the total weight of element e.g. foam or material, unless explicitly otherwise specified. In the present disclosure, all amounts are given in wt.-%, unless clearly stated otherwise or obvious from context. In the present disclosure, furthermore all amounts given in wt.-% in a particular foam add up to 100 wt.-%. The weight percent are thereby calculated by dividing the mass of each component by the total mass of the foam, unless indicated otherwise or clear from context. 
     As used herein, the term “foam” is used interchangeably with the term “mousse”. The foam of the present invention is an open pored foam according to certain embodiments. An open pored foam as used herein is to be understood as a foam which can be considered as being formed of a plurality of interconnecting pores (formed out of a structural material derived from the foam forming agent cooperating with the interacting components such as the foam stabilizing agent, solid components such as tobacco particles and some solvent, etc.) which are able to contain fluid, in particular a mixture of humectant/liquid aerosol-forming substrate and air, wherein at least a significant portion (e.g. greater than 50% by volume) of the pores in the foam are fluidly connected with each other, contrary to a closed-cell foam, wherein the majority of the pores form discrete pockets, each completely enclosed by pore-forming material so as to substantially prevent fluid from passing freely between pores. It is currently believed that the foams, particularly mousses, formed as described herein are largely open-pored foams, particularly mousses, because after heating the foam, particularly mousse, to release vapour, substantially all of the humectant appears to be released based on measuring the weight of the foam, particularly mousse, portion before and after heating, which could not be readily explained if the humectant was not able to travel through neighbouring pores to reach the surface of the foam, particularly mousse, portion. However, alternative explanations cannot be totally excluded—for example closed pores could perhaps be opened by rupturing a closed cell wall as a result of the pressure of vaporized gas, etc. For example, according to the definition of the present invention, the term “foam” cannot be equate to terms like gel, cream or slurry. 
     It is disclosed herein that according to the gist of the present invention, in some most preferred embodiments, the aerosol-generating material comprises a mixed arrangement of randomly-oriented fibres and an aerosol-generating tobacco-containing substrate in a semi-solid state such as a foam or a paste. The aerosol-generating tobacco-containing substrate for example can be made up of at least 20 wt. %, or between 25 wt. % and 40 wt. % of the total dry weight for instance of the aerosol-generating material. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Present invention relates to an aerosol-generating material, comprising a mixed arrangement of randomly-oriented fibres and an aerosol-generating substrate in a semi-solid state such as a foam or a paste. The aerosol-generating material is therefore a mixed of fibres with semi-solid aerosol-generating substrate such as foam, paste or cream, preferably containing tobacco material i.e. fine particulates, powder or the like. Thanks to the aerosol-generating material of the present invention, higher vapour performance of the aerosol-generating article is observed as the randomly oriented fibre with the aerosol-generating substrate allow more heated air to contact with the surface of the aerosol-generating substrate of the aerosol-generating material. Moreover, due to the texture and composition of the present invention, it successfully reproduces a taste closer to the conventional tobacco consumables. 
     To this end, it is disclosed that the aerosol-generating material is the “final version” of the “intermediate version” of the aerosol-generating substrate, wherein the aerosol-generating material comprises not only the aerosol-generating substrate but also a mixture of other substances or components such as water, humectants, flavourant, additives, binders and/or other minute compounds. 
     The inventors found that when the aerosol-generating material or aerosol-generating article comprises tobacco components from two different distinct components i.e. randomly-oriented fibres especially tobacco-containing fibres and semi-solid aerosol-generating substrate such as tobacco mousse, due to their different heating rate and heating temperature, the aerosol-generating material gives a stronger and richer tobacco flavour which is generally preferred by some users. Moreover, when the fibres are randomly-oriented, more space are created between the fibres, hence it encourages heated air to interact more often with the fibre surface, thereby increasing the vapour performance of the consumables. 
     The advantage of the present invention is particularly observed when the (tobacco-containing) semi-solid aerosol-generating substrate e.g. foam or mousse are applied to the surface of the fibres for example through coating, spraying, dipping or painting, due to different consistency of the materials (fibres and layer of coat applied thereon), when the aerosol-generating material is exposed to the heat, a strong, rich tobacco sensation of aerosol/vapour is firstly produced due to the layer of the semi-solid aerosol-general substrate is quickly evaporated, followed by an extended heating period thanks to the randomly-oriented fibres which is under the layer of the aerosol-generating substrate. It is foreseeable that when the randomly-oriented fibres are made of tobacco-containing material, the heating time of the aerosol-generating material will be extended and accompanied by prolonged tobacco-containing aerosol/vapour. Similar results (but to a less extent) can be observed when the semi-solid aerosol-generating substrate is not applied or coated to the surface of the randomly-oriented fibres. 
     In some instances where the aerosol-generating material comprises (randomly-oriented) fibre materials, especially tobacco-containing material, these fibres oftentimes are direct products taken from reconstituted tobacco. Reconstituted tobacco uses the leftover bits from tobacco production which include the stems and leaf scraps that result from stripping tobacco leaves. 
     There are a few different processes that can be used to make reconstituted tobacco. The primary three processes are nanofiber, paper making, and slurry type. 
     The first process being the “nanofiber reconstituted tobacco production process”. The process starts with manufacturers grinding the tobacco down and then removing sand and other non-tobacco materials. The tobacco then goes through a mixing process, which includes three stages: solid, liquid, and turbo mixing. After that, it gets laminated into sheets, dried, and cut and packed. 
     The second process being the so-called “papermaking process”. It starts out with a similar process; the tobacco gets ground down and mixed with water. The fibre materials get turned into the paper we mentioned earlier. Once the paper is laminated, they spray the water mixture over the sheets to add the components back in. 
     The third process is the so-called “slurry-type process”, wherein the fibre materials and soluble materials never get separated. Instead, they all get mixed into water to create a slurry. This gets spread out and has the water evaporated out of it to create the reconstituted sheets. 
     In all the above three methods, reconstituted tobacco sheets are pressed, compacted and subsequently dried. Hence, it is foreseen that even when a small portion of such reconstituted tobacco is used, due to the compactness and thickness of the material, the vapour performance resulting from such material is poor. 
     The aerosol-generating material according to the present invention, therefore circumvents the problem by using randomly-oriented fibres. Thanks to the randomly-oriented fibres (and preferably single stranded and has a short length e.g. less than 5 mm), it gives a superior vapour performance as almost all or most of the aerosol-generating material can be heated properly to release the vapour and/or aerosol as more surface area of the aerosol-generating material can be contacted with the heated air. This in turn reduces the waste of the unused consumables. 
     To this end, it is mentioned that the fibres of the present invention are preferably single stranded fibre, having a length of preferably less than about 5.0 mm, preferably between about 0.2 mm and about 3.5 mm. The single stranded fibre may be obtained from a tobacco plants as described above, or from reconstituted tobacco wherein the sheet is shredded finely in order to be within the desired size and thickness. Preferred tobacco parts are such as from stem and/or leaf. 
     The randomly-oriented fibre may then be mixed with the aerosol-generating substrate together with one or more binders, water, humectants, additives or etc. for the formation of the aerosol-generating material. The aerosol-generating substrate may comprise of tobacco-containing material, propylene glycol, glycerine, water and/or aerosol-forming agent and aerosol-stabilizing agent, where these components are mixed and provided in a semi-solid state such as foam or mousse. 
     According to a preferred manufacturing process, the aerosol-generating substrate can firstly be produced. The aerosol-generating substrate which is in form of a semi-solid state such as foam or mousse can be used to coat, paint or applied to at least part or full of the surface of the fibres together with other components or substances such as binder, humectant, additives or flavouring for creating the aerosol-generating material. The coating method are for instance spraying, filling, dipping, bathing, coating or extruding. 
     Once these components or substances are applied to the non-oriented fibres, drying process through air-dry or through oven-dry can take place such that the aerosol-generating material is prepared. 
     The aerosol-generating material can be adhered to one or more surfaces of a support element or carrier element such that a shape can be formed. The support element can be for instance any 3D object, a frame, a woven or a non-woven fabric, a backing material and/or a sheet. 
     In some cases, the randomly-oriented fibres can be made up of the material such as shredded reconstituted tobacco, tobacco derivatives such as leaves portion, stem portion or lamina portion. The randomly-oriented fibres have a predominantly short length and may appear as if sawdust. The mean diameter of the aerosol-generating fibres may be less than 2 mm or preferably less than 1 mm. The aerosol-generating substrate preferably comprises tobacco-containing material that is in form of fine particle (less than about 0.5 mm in diameter). 
     The fibres used in the present invention according to some embodiments may be provided in length between 0.5 mm and 2.0 mm, having cross-sectional profile such as round, rectangular, ovule, polygon or irregular shapes. The fibres may be flat or square or having edges. The randomly-oriented fibres may be made from the semi-solid aerosol-generating substrate, any fibre materials such as cellulose fibre. 
     It is disclosed herein that the semi-solid state aerosol-generating substrate of the present invention according to certain embodiments are not bound and/or connected to a carrier or to fibres, i.e. can be used as is, i.e. as free-standing foam. Particularly, the aerosol-generating substrate (e.g. foam) are not bound to a substrate according to certain embodiments, but rather are used as is. Thus, according to certain embodiments, the present aerosol-generating substrate (e.g. foam) are stable enough to be used as is, i.e. are self-supporting, and have a sufficient stiffness so that they are not bent when picked up on their own and do not require a further stabilizing substrate. 
     According to certain embodiments, the present aerosol-generating substrate (e.g. foam) are biodegradable. 
     Nevertheless, according to some preferred embodiments, the semi-solid aerosol-generating substrate e.g. foam can be coated to the surface of the randomly-oriented fibres. 
     When the semi-solid aerosol-generating substrate is provided in form of a mousse or a foam, the foam structure in the foams is not particularly limited and can, for example, comprise trapped air bubbles and/or bubbles of other gases such as nitrogen or oxygen, e.g. air bubbles. It can be provided as an open structure with a large surface area, which enables heat and aerosol to circulate through the foam, particularly during heating, thus providing uniform heating, a good quality aerosol, and extremely efficient extraction of the tobacco-containing agent and/or the inhalable agent. According to certain embodiments the foam is an open pored foam. This means that the foam has an open pore structure according to certain embodiments. With an open pored structure, i.e. an open pored foam, circulation of heat and aerosol is enhanced. It can be a liquid foam, a dry foam, a solid foam, or a pellet, preferably a dry foam, a solid foam or a pellet. The foam forming agent generally can trap the bubbles when the foam is formed, e.g. whipped, and the foam stabilizing agent can reduce and even prevent breakdown of the foam. 
     In the present invention, ingredients for forming the aerosol from the semi-solid state aerosol-generating substrate (e.g. foam) comprised of for example the aerosol-forming agent, the form-foaming agent, the foam-stabilizing agent, the tobacco-containing agent, the inhalable agent and/or at least one non-tobacco-flavoring agent, and the solvent are not particularly restricted. Also a gas used for aeration is not particularly restricted, and can be e.g. air. Also further components can be admixed. According to certain embodiments, essentially no further components or no further components are admixed, though. 
     Propylene glycol as used in the present invention is to be understood as propane-1,2-diol. Glycerin or glycerol as used in the present invention is to be understood as 1,2,3-propanetriol. These components are suitable to be transformed into semi-solid state of aerosol-generating substrate e.g. foam, under methods as described herein. In some embodiments, the foam may comprise fine particulate of tobacco material or tobacco-flavoring agent. 
     The aerosol forming agent can further comprise water. According to certain embodiments, no water is contained, though, since water in aerosol form can burn the mouth of a user. Water can be contained in an amount of 0-15 wt.-% of the weight of the foam, e.g. 5-10 wt.-%. 
     The method of aeration is not particularly restricted and can involve e.g. an injection of air, a whipping in of air—e.g. a mixing with a sufficiently large paddle/shuffle and/or a sufficient paddle movement and/or at sufficient lower speed so that air can be introduced into the mixture, bubbling air through the mixture, etc. For example, aeration can be carried out using a sufficient mixing machine similar to a mixer for preparing a mousse, e.g. a Krups Prep &amp; Cook HP  5031  mousse whipping shuffle, and or by injection air with an aerator, e.g. like Mondomix aerator. Aeration can be carried out at a suitable temperature, e.g. at room temperature (around 20-24 ° C.), 30-80° C., e.g. to 35-75° C., preferably between and including 30-60° C. In the present methods it is not excluded that aeration is carried out concomitantly with a mixing and/or in a step of adding an ingredient, e.g. when using whipping. 
     In the present invention, the foam-stabilizing agent is not particularly limited as long as it can stabilize the foam to some extent after formation. According to certain embodiments, the foam stabilizing agent of the present foam is selected from the group consisting of cellulose gum, hydroxyalkylated carbohydrates, and mixtures thereof. Both of the cellulose gum and the hydroxyalkylated carbohydrates are not particularly restricted. According to certain, preferred, embodiments, the foam-stabilizing agent is a cellulose gum, particularly a carboxymethylcellulose, or a derivative thereof. An exemplary, preferred, cellulose gum which may be used in the present invention is CEKOL® 2000 and/or Ceroga 4550C (C.E. Roeper GmbH), a purified sodium carboxymethylcellulose each. Another class of suitable foam stabilizing agents are hydroxyalkylated carbohydrates, and more preferably cellulose ethers and derivatives thereof. A cellulose ether or derivative thereof that can be used can have at least one substituent selected from the group consisting of methyl, ethyl, hydroxyethyl and hydroxypropyl groups. It can further be substituted with a linear or branched substituted or unsubstituted alkyl radicals having 1-20 carbon atoms or an aralkyl radical having 7 to 20 carbon atoms. Such radical is preferably attached by an ether linkage. Suitable substituents can e.g. a hydroxy group, a carboxy group with 1 to 4 carbon atoms, etc. According to certain embodiments the cellulose ether is selected from hydroxyethylcellulose, methylcellulose, methylhydroxyethylcellulose, ethylhydroxyethylcellulose, and mixtures thereof. Furthermore, mixtures of different cellulose gums, different hydroxyalkylated carbohydrates, and mixtures of one or more cellulose gum with one or more hydroxyalkylated carbohydrate, as well as derivatives of one or either thereof, can be used. Also included as derivatives are salts of these cellulose ethers, preferably alkali metal salts thereof, e.g. sodium and/or potassium salts thereof. 
     Also the foam-forming agent is not particularly restricted. According to certain embodiments, the foam-forming agent of the present foam is selected from the group consisting of agar, gellan gum, lecithin, polyglycerol esters of fatty acids, glycerol esters of fatty acids, sorbitan esters of fatty acids, and/or mixtures thereof, without being limited thereto. A preferred foam-forming agent is gellan gum. Glycerol esters can be prepared by standard esterification methods. If glycerol esters of fatty acids are used, the foam-forming agent can suitably be a compound such as glycerol monostearate and/or glycerol monooleate. Polyglycerol esters can be prepared by polymerizing glycerin under alkaline conditions suitably followed by reacting them with specific fatty acids. Suitable polyglycerol esters can be hexaglycerol monooleate, octaglycerol monostearate and/or octaglycerol monooleate. Sorbitan esters of fatty acids used in certain embodiments of the present invention can be sorbitan monostearate, sorbitan monooleate and/or sorbitan mono palmitate. Furthermore, any possible combinations of compounds belonging to the above mentioned classes can be used. 
     The aerosol-generating substrate provided in a semi-solid state such as a foam or a mousse can be obtained as follows: the mixture of aerosol-generating substrate (which may comprise tobacco-containing fine particles, propylene glycol, glycerin and etc.) is whipped constantly and aerated and may further comprise the steps of adding foam-stabilizing agent and followed by cooling of the mixture. This does not exclude that other aeration steps are also being carried out, and according to certain embodiments, one, two or preferably all of the optional aeration steps are carried out in the present methods. Also it is not excluded that aeration is carried out already concomitantly with a mixing and/or addition step. 
     The support element may serve as a mould for the formation of the aerosol-generating article. In other words, the support element may have a skeleton structure such that the aerosol-generating material can be applied (e.g. sprayed, dipped, coated, painted or etc.). The skeleton structure may have many perforations that are small enough that the fibres are sufficient to cover the openings but it has sufficient space to allow air flow passing through the openings. 
     The aerosol-generating material according to the present invention may be sprayed to a support element such as a base or a backing material, for instance a heat-resistant non-woven mesh. The aerosol-generating material may either adhere to the backing material, forming a sheet, or do not adhere to the backing material, resulting in a 3D and self-carrying mesh structure. The aerosol-generating material may be applied to all surfaces of the support element, or only to the exterior surfaces. 
     EXAMPLE 
     The present invention will now be described in detail with reference to examples thereof. However, these examples serves merely as illustrative purpose and do not limit the scope of the invention. 
     Firstly, in order to prepare for the aerosol-generating substrate, the propylene glycol, the glycerin and the purified water were whipped and aerated for 5-10 min at 45° C. using a Krups Prep &amp; Cook HP5031 mousse whipping shuffle. When whipping up the mousse, the speed has to be adjusted so that the volume visibly increases and small bubbles appear and partly stay in the foam. If whipping is too fast then mixing will take over and the foamy structure is going to collapse, thus back to fluid. As one option, whipping is started slowly and the whipping speed is slowly increased as the foam begins to develop a lighter, more mousse-like texture; the speed is backed-off by about 10% if it is noticed that the mousse seems to be reducing its mousse-like texture and becoming seemingly less aerated. In order to preserve the foamy structure for creating the stable portion, a sudden cooling with ice or cool water is recommendable. Using the above mentioned Krups device, the best results can be obtained with a speed in between 60 and 200 rpm. Adaptation is within the skilled person&#39;s knowledge in accordance with the above description. 
     In a next step, the gum was added and the mixture was whipped and aerated for 5-10 minutes. Afterwards the tobacco-containing material (e.g. powder) was added and whipping and aeration were carried out for 5-10 min. The binder was added and the mixture was again whipped and aerated for 5-10 min. Finally the mixture was cooled to 10° C. within 10 minutes and aged at 45° C. or at room temperature for 8 hours. 
     The aerosol-generating substrate was subsequently applied to the surface of the randomly-oriented fibres (which are preferably single stranded having length less than about  5  mm) through mixing, spraying, dipping, bathing or coating. After a drying step, the aerosol-generating material is prepared. The randomly-oriented fibres may be originated from reconstituted tobacco sheet, wherein the sheet is shredded, blown and mixed to the extended that the fibres have a mean length less than about 5 mm. This can be done through a sieve to filter out those larger particles. 
     The aerosol-generating material was then applied to one or more surfaces of the support element such that an aerosol-generating article can be created. The support element may serve as a mould for the formation of the aerosol-generating article. In other words, the support element may have a skeleton structure such that the aerosol-generating material can be applied (e.g. 
     sprayed, dipped, coated, painted or etc.). The skeleton structure may have many perforations that are small enough that the fibres is sufficient to cover the openings. Air flow may nonetheless flow through these perforations, allowing a better vapour performance.