JP2023501121A - Method and foam for forming foam for aerosol-generating articles - Google Patents

Abstract

The present invention provides improved venting of foams and methods of forming said foams for aerosol-generating articles, comprising (a) an aerosol-forming agent, a foam-forming agent and optionally a solvent and/or at least (b) adding a tobacco-containing agent and/or an inhalable agent to the mixture; and (c) adding a foam stabilizer. (d) cooling the mixture, wherein the mixture is aerated after adding the foam stabilizer and/or after cooling the mixture, and sodium bicarbonate is added to the mixture prior to cooling the mixture; The content of sodium bicarbonate relates to processes wherein the content is less than 1% by weight, based on the total weight of the foam. [Selection figure] None

Description

The present invention relates to a method of forming a foam for an aerosol-generating article comprising a tobacco-containing and/or inhalable agent, an aerosol-forming agent, a foam stabilizer and a foam-forming agent. The present invention also relates to foams produced by the method and foams with certain improved aeration.

A wide variety of aerosol-generating articles and devices thereof for use as novel forms of smoking have proliferated in recent years and have become commercially available in the marketplace. These include one of the best known new forms, electrically heated e-cigarettes, in which an aerosol is generated by the transfer of heat from a heating element of an aerosol-generating device to an aerosol-generating substrate or material. be done.

In heat-not-burn aerosol-generating articles, the aerosol-forming substrates are reportedly heated to relatively low temperatures, eg, less than 350° C., to avoid their combustion. The charge of the inhalable aerosol can then be expelled from the aerosol-generating article. The emitted aerosol results from an aerosol-forming agent incorporated into the tobacco material, which may be particulate or particulate.

Homogenized tobacco material is often used in the manufacture of tobacco products. Parts of tobacco plants that are less suitable for the production of cut fillers, such as tobacco stems or tobacco dust, are typically the materials used for homogenized tobacco material. These reconstituted tobaccos may be provided, for example, in powder, sheet or foam (mousse) form.

The described foam tobacco product is one example known in the prior art, primarily in the field of reconstituted tobacco products. The manufacturing process typically includes the steps of forming a reconstituted tobacco sheet from pulverized tobacco particles using a foam former and a foam stabilizer, followed by crushing the reconstituted sheet, and blending with natural tobacco shreds. and the step of Reconstituted tobacco products are commonly used to manufacture cigarettes.

Reconstituted tobaccos in sheet or powder form generally have better market acceptance than reconstituted tobaccos in foam or mousse form due to their closer texture and consistency to the original tobacco material. be done. However, foamed reconstituted tobacco generally has the inherent advantage of requiring less tobacco-containing material to be provided in, for example, an aerosol-generating consumable, compared to those provided in sheet or powder form. Due to the higher delivery capacity of volatile compounds such as nicotine, less tobacco-containing material is required to achieve the same results as other forms such as reconstituted tobacco sheets. As a result, lower manufacturing costs can be achieved.

Accordingly, it would be desirable to provide improved methods of forming foams for aerosol-generating articles, as well as improved foams capable of delivering more conventional smoking articles.

The inventors of the present invention have found a solution to the problems discussed above through methods and foams for forming foams for aerosol-generating articles.

A first aspect of the invention is therefore a method of forming a foam for an aerosol-generating article comprising:
- mixing an aerosol-forming agent, a foam-forming agent and optionally a solvent and/or at least one non-tobacco flavorant, preferably under heating;
- adding tobacco-containing and/or inhalable agents to the mixture;
- adding a foam stabilizer;
- cooling the mixture;
The mixture is aerated after addition of the foam stabilizer and/or after cooling of the mixture, sodium bicarbonate is added to the mixture prior to cooling of the mixture, and the content of sodium bicarbonate is based on the total weight of the foam. It is to provide a method that is less than 1% by weight.

A second aspect of the present invention is a foam comprising: a tobacco-containing and/or inhalable agent, an aerosol-forming agent, a foam-forming agent, sodium bicarbonate and a foam-stabilizing agent;
The weight of the tobacco-containing and/or inhalable agent is 0.1-33% by weight of the foam and the weight of the aerosol-forming agent is 10-80% by weight of the foam, preferably 40%. ~70% by weight and the weight of sodium bicarbonate is less than 1% by weight based on the total weight of the foam.

The inventors have found that the foams made according to the present invention unexpectedly improve the tobacco flavor of the aerosol-generating article and improve the stability, processability of the foams, thanks to sodium bicarbonate (NaHCO ₃ ). as well as improved pore volume increased. According to a series of observations and tests performed, foams containing sodium bicarbonate have increased airflow values (pore volume) of the foam/mousse compared to tobacco foams without sodium bicarbonate. Therefore, it has been observed to be particularly suitable for compact molded substrates, for example when the substrates are molded into various forms such as cards, pellets and sticks. Furthermore, it has been found that not only is the porosity of the foam significantly increased, but the texture of the resulting product is fluffier and the tobacco flavor and aroma much sought after by consumers is greatly increased.

The content of sodium bicarbonate is less than 1% by weight, based on the total weight of the foam according to the invention. Thanks to the sodium bicarbonate reacting with the mixture, which is preferably acidic, a gas such as for example carbon dioxide is released which, in addition to the aeration of the mixture, contributes to the increased porosity of the foam thereat.

According to some embodiments, the pH of the mixture is adjusted to a pH value of 5-9, such as 5-8.5. In other embodiments, an acidity of eg 4 to 6.9 is preferred. Such acidic conditions enhance the release of carbon dioxide from the sodium bicarbonate reaction, thus providing the foam with increased pore volume.

Further, in some embodiments, the method further comprises adding a binder to the mixture, preferably prior to the step of aeration or prior to the step of cooling the mixture. Binders are used in the present invention to bind together fine particles such as tobacco-containing agents and other agents.

In yet another embodiment, the binder content is less than 15% by weight, based on the total weight of the foam.

According to one preferred embodiment, the sodium bicarbonate content is about 0.25% to 0.75% by weight based on the total weight of the foam. We have found that 0.75 wt% sodium bicarbonate, based on total foam weight, produces greater than 0.25 wt% open pore foam, based on total foam weight. I found A higher percentage of open pore foam allows for increased aeration of the foam, thus improving the vapor released from the tobacco-containing foam.

In one embodiment, the pH of the mixture is adjusted to a pH value of 5-9, such as 5-8.5.

In one particularly preferred embodiment, sodium bicarbonate is added back to the mixture after the step of cooling the mixture. After cooling the mixture, for example after at least 6 hours at room temperature (approximately 22° C.), an additional amount of sodium bicarbonate is added (e.g. totaling less than 1% by weight of sodium bicarbonate based on the total weight of the foam), Sodium bicarbonate reacts well with the cooled (to room temperature) mixture by releasing a gas such as carbon dioxide, thereby aerating the foam. The external aeration step could further enhance the aeration of the foam, thereby creating a higher percentage of pore volume in the foam.

According to some preferred embodiments, the foam stabilizer has a viscosity of 300 mPas to 3,000 mPas, preferably 400 mPas to 2,500 mPas, more preferably 500 mPas to 2,000 mPas, measured at room temperature, ie about 22°C. It has viscosity.

Further, according to some embodiments, the foam forming agent comprises from 300 g/cm3 to 3,000 g/cm3, preferably from 400 g/cm3 to 2,500 g/cm3, measured at room temperature, ie, about 22°C. More preferably it has a gel strength of 500 g/cm3 to 2000 g/cm3 and/or the foam former has a It has viscosity.

According to yet another embodiment, the foam is extruded into pieces and/or shaped after cooling.

In some embodiments, the foam has at least 5 vol. % pore volume.

In yet another embodiment, the foam forming agent is a non-protein containing polysaccharide and the weight of the foam forming agent is less than 20% by weight of the total weight of the foam.

According to some preferred embodiments, the present invention uses a solvent, preferably water and/or acid and/or ester, in an amount of up to 15% by weight, preferably up to 5% by weight, based on the total weight of the foam. further includes

According to one preferred embodiment, the foam is an open-pore foam. That is, more than 50% of the foams are open pore foams, ie fluidly interconnected.

In one particularly preferred embodiment, the foam has at least 20% of the cells within the foam having a diameter between 25 μm and 50 μm and/or at least 15% of the cells having a diameter between 51 μm and 100 μm and/or including at least 11% having a diameter between 101 μm and 171 μm.

According to another embodiment, the foam has at least 30% or at least 40% of the cells within the foam having a diameter of 25 μm to 50 μm and/or at least 23% or at least 30% of the cells having a diameter of 51 μm to 100 μm. and/or at least 15% or at least 22% of the cells have a diameter between 101 μm and 171 μm.

"About" or "approximately" with respect to a given numerical value is meant to include numerical values within 10% of the specified value. All values given in this disclosure should be understood to be supplemented by the term "about" unless the context clearly dictates otherwise.

The indefinite article "a" or "an" does not exclude a plurality and should therefore be treated broadly.

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.

Tobacco-containing material is any compound that contains and/or carries tobacco constituents, such as tobacco, tobacco particles, tobacco flavor and/or nicotine, either artificially contained or contained naturally in tobacco. , mixtures, particulate matter and/or solutions. In contrast, an example for an artificially added non-tobacco specific flavor would be menthol.

As used herein, the term "aerosol-generating article" produces an aerosol comprising an aerosol-generating material that is intended to be heated, rather than incinerated, to release volatile compounds capable of forming an aerosol. It refers to an aerosol-generating article for

As used herein, the term "aerosol-generating material" refers to a material that, when heated, can release volatile compounds that can form an aerosol. Aerosols generated from the aerosol-generating materials of the aerosol-generating articles described herein can be visible or invisible, vapors (e.g., fine particles of substances in a gaseous state that are normally liquid or solid at room temperature) as well as It may contain droplets of gas and condensed vapor.

The aerosol-forming agent can be any compound, mixture and/or solution capable of forming an aerosol, eg, when heated and/or in admixture with tobacco-containing agents. Well-known examples include humectants such as glycerin and propylene glycol, other alcohols such as ethanol, and the like.

As used herein, an open-celled foam has a plurality of interconnected pores (such as foam stabilizers, tobacco particles, etc.) that can contain a mixture of fluids, particularly humectants/liquid aerosol-forming substrates, and air. It should be understood to be a foam that can be considered to be formed from a solid component and a structural material derived from a foam-forming agent associated with interacting components such as some solvent. A, wherein at least a majority (e.g., greater than 50% by volume) of the pores in the foam are fluidly connected to each other, in contrast to closed-cell foams, wherein a majority of the pores forms separate pockets, each completely surrounded by pore-forming material, so as to substantially prevent fluid from freely passing between the pores. It is presently believed that the mousses formed as described herein are mostly open pore mousses, which, after cooling or heating the aerosol-generating material comprising sodium bicarbonate, are treated with steam. is released from the mousse and substantially all of the humectant appears to be released based on measurements of the weight of the mousse portion before and after heating, the humectant passing through adjacent pores to the surface of the mousse portion. could not be easily explained. However, alternative explanations cannot be ruled out entirely - for example, closed cells could possibly be opened by rupturing the closed cell walls as a result of vaporized gas pressure or the like.

Electronic cigarettes (e-cigarettes) or electronic pipes or similar devices such as heated devices referred to in the present invention are not particularly limited and may be used to provide an aerosol for inhalation to the user. It includes, according to certain embodiments, mouthpieces, heaters, containing parts such as pods, sticks, capsules and casings.

Weight percents used herein should be understood to be weight percents based on the total weight of the foam, unless otherwise specified. In this disclosure, all amounts are given in weight percent unless explicitly stated otherwise or clear from the context. In this disclosure, all amounts further given in weight percent add up to 100 weight percent. Thus, weight percents are calculated by dividing the weight of each component by, for example, the total weight of the foam, unless otherwise indicated or clear from context.

As used herein, unless expressly specified otherwise, volume percentages are to be understood as volume percentages based on the total volume of the foam. In this disclosure, all amounts given as volume % in a given foam add up to 100 volume %. Accordingly, volume percents are calculated by dividing the volume of each component by the total volume of the foam, unless otherwise indicated or clear from context.

Similarly, the air permeability value (also known as pore volume as used herein) indicates the volume percent of a foam or mousse made up of air. The actual aeration value of the sample is estimated using the following procedure: A sample of "foam" is subjected to any action (e.g., whisking or aerating with an aerator) to aerate the "foam". A known volume of this unexpanded "foam"/material is measured. A sample having the same known volume as the aerated foam, produced after performing an aeration step (e.g., a step such as bubbling or aeration with an aerator), is then reweighed and the percentage of weight is A reduction rate is calculated. By assuming that the unfoamed material has zero aeration, and that air has negligible weight, this directly indicates that the measured weight loss is between the unfoamed material and the (weightless) air. directly yields an estimate of the ventilation value by assuming that it arises from the permutation of . For example, if 4% less weight is observed for the same volume of foamed material as compared to the volume of unfoamed material, then 4% of the unfoamed material is considered to be replaced by air; This means that the volume percent of air is 4%.

The particle size disclosed in the present invention can be measured by any suitable method such as sieving or laser diffraction, preferably sieving.

(Dynamic) viscosity as described herein refers to the flow behavior of a liquid. Dynamic viscosity is defined as the internal frictional resistance of a liquid to the application of pressure or shear stress. Dynamic viscosity is expressed in mPas (milliPascal seconds) and is determined using a rotational viscometer. Viscosity measurements are performed at room temperature, ie 22°C.

As used herein, “cooling” refers to room temperature (approximately 22-24° C.) for at least 60 minutes, or a temperature below 16° C. for at least 10 minutes, or more preferably 12° C. for at least 5 minutes. It should be understood to have a temperature below the temperature.

As used herein, "venting" should be understood to be the introduction of air or gas into the material through an external process. Aeration can be accomplished by frothing, beating, mixing or through aeration with an aerator such as, for example, the Krups Prep & Cook HP 5031 Mousse Whisk Shuffle, or by blasting air with an aerator such as, for example, the Mondomix aerator. can. Aeration may be performed at any suitable temperature. The duration of aeration can be, for example, 1, 2, 3, 4, 5 or 10 minutes or longer.

The present invention relates to methods and foams for forming foams for aerosol-generating articles. It has been found that a significant increase in aeration of the tobacco mousse is observed when the aerosol-generating tobacco-containing mixture for forming the foam additionally contains sodium bicarbonate. This observation can be attributed to the fact that more gases such as carbon dioxide are released from the foam mixture, especially when the mixture is provided in acidic conditions. In other words, the pore volume of the foam increased significantly compared to the foam without sodium bicarbonate.

Interestingly, this result of foams producing a higher percentage of pore volume was observed only in foams containing sodium bicarbonate (NaHCO ₃ ), whereas in foams containing sodium carbonate (Na ₂ CO ₃ ) have observed less pronounced results. Without being bound by theory, this phenomenon is likely due to the corrosive properties of sodium carbonate, while sodium bicarbonate exhibits less corrosive properties. Of these two basic compounds, sodium carbonate is the stronger base because it is also diprotic, a term given to those that react with two equivalents of acid. After reacting with one equivalent of acid, the acid then converts to monobasic sodium bicarbonate. For this reason, sodium bicarbonate, a weakly basic (alkaline) compound, is believed to always generate gas, thereby allowing better aeration of the foam. Therefore, it is preferred that sodium bicarbonate is added to the mixture for foam formation in a more acidic state, eg with a pH of 5.0-6.9.

Foams according to the invention are particularly suitable to be molded into compact substrates such as in the form of thin cards, pellets or sticks. If the foam substrate is compressed into, for example, a very thin foam (approximately 1 mm), the pore volume of the foam becomes very important as it determines the airflow efficiency of the foam. Therefore, existing tobacco foam products are not adapted to be compressed as the foam/mousse aeration is significantly reduced when compressed.

For this reason, due to the sodium bicarbonate the foam preferably contains less than 1% of the total weight of the foam, the foam according to the invention has a better performance due to the higher pore volume in the foam. achieve ventilation. This in turn increases the vapor/aerosol emission. Because of this, not only is the foam more stable and fluffy, but it is also capable of releasing more intense tobacco flavor and aroma after heating of the foam, thus unexpectedly improving the flavor of the tobacco. It has been found that The aeration of the substrate achieved thanks to the addition of sodium bicarbonate significantly reduces the total weight of the substrate portion compared to the same substrate portion without sodium bicarbonate for a given substrate portion format. In addition, it is further beneficial that a reduction of 20% to 40% can actually be achieved.

It is disclosed herein that foams according to certain embodiments are not tied and/or connected to a carrier, i.e., can be used as is, i.e., as a self-supporting foam. Notably, the foam is not tied to a substrate according to certain embodiments, but rather is used as is. Thus, according to certain embodiments, the foam is sufficiently stable to be used as is, i.e., free-standing, does not bend when picked up by itself, and is otherwise stabilizing. It is rigid enough to not require a substrate.

According to certain embodiments, the foam is biodegradable.

The foam structure in the foam is not particularly limited and can include, for example, trapped air bubbles and/or bubbles of other gases such as nitrogen or oxygen, such as air bubbles. The foam structure allows heat and aerosols to circulate through the foam, especially during heating, thus providing uniform heating, good quality aerosols and extremely high levels of tobacco-containing and/or inhalable agents. It can be provided as an open structure with a large surface area that provides efficient extraction. According to certain embodiments, the foam is an open-cell foam. This means that the foam has an open pore structure according to certain embodiments. Having an open pore structure, ie being an open pore foam, enhances heat and aerosol circulation. The open-cell foam can be liquid foam, dry foam, solid foam or pellets, preferably dry foam, solid foam or pellets. Foam formers are generally capable of trapping bubbles as the foam is formed, eg, as it is frothed, and foam stabilizers can reduce and even prevent foam collapse.

The bubbles of the foam may have an average diameter in the range of 25-130 μm, such as 45-110 μm, such as 70-85 μm, and about 97% of the bubbles are 180 μm or less, such as 160 μm or less, such as 140 μm or less, such as 120 μm. It can have the following diameters: According to certain embodiments, at least 20%, preferably at least 30%, more preferably at least 35% of the bubbles, which may also be referred to as pores, within the foam have a diameter between 30 μm and 55 μm, and/or at least 15%, preferably at least 25%, more preferably at least 30% of the bubbles have a diameter between 51 μm and 100 μm, and/or at least 15%, more preferably at least 20% of the bubbles have a diameter of 101 μm It has a diameter of ~171 μm.

The diameter here can be measured using eg microscopy methods, eg using a Digital Microscope VHX Keyence. However, the method for measuring the bubble size is not particularly limited. The foam may be molded into any suitable shape for insertion into an e-cigarette. According to certain embodiments, the foam has at least one blind or hole through the foam for circulation and aerosol transmission, e.g. Contains 8, 9, 10 or more holes.

Examples of shapes are through holes of any shape, e.g. about 1 cm in diameter, e.g. may be of any shape or size. According to certain embodiments, the foam has a large surface area, e.g., at least one surface with at least one distance between any two sides of the surface, or with a diameter sufficiently greater than the thickness of the foam. It has a structure with a surface. The foam may thus be in the form of a disc, eg a cylindrical disc, a thin plate or the like. According to certain embodiments, at least one hole passes through at least one surface with at least one distance between any two surfaces or with a diameter sufficiently greater than the thickness of the foam. .

In the present invention, the foam stabilizer is not particularly limited as long as it can stabilize the foam to some extent after formation. According to certain embodiments, the foam stabilizer of the foam is selected from the group consisting of cellulose gums, hydroxyalkylated carbohydrates and mixtures thereof. Neither cellulose gum nor hydroxyalkylated carbohydrates are particularly limited. According to certain preferred embodiments, the foam stabilizer is a cellulose gum, especially carboxymethylcellulose or a derivative thereof. Exemplary preferred cellulose gums that may be used in the present invention are CEKOL® 2000 and/or Ceroga 4550C (CE Roeper GmbH), each of which is purified sodium carboxymethylcellulose. Another class of suitable foam stabilizers are hydroxyalkylated carbohydrates, more preferably cellulose ethers and their derivatives. The cellulose ethers or derivatives 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 be further substituted with linear or branched substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms or aralkyl groups having 7 to 20 carbon atoms. Such groups are preferably linked by ether linkages. Suitable substituents can be, for example, hydroxy groups, carboxy groups of 1 to 4 carbon atoms, and the like. According to certain embodiments, the cellulose ether is selected from hydroxyethylcellulose, methylcellulose, methylhydroxyethylcellulose, ethylhydroxyethylcellulose and mixtures thereof. Additionally, different cellulose gums, mixtures of different hydroxyalkylated carbohydrates and mixtures of one or more cellulose gums and one or more hydroxyalkylated carbohydrates and derivatives of one or any thereof can be used. . Further derivatives include salts of these cellulose ethers, preferably alkali metal salts thereof such as sodium and/or potassium salts thereof.

Also, the foam-forming agent is not particularly limited. According to certain embodiments, the foam former of the 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. but not limited to: A preferred foam former is gellan gum. Glycerol esters can be prepared by standard esterification methods. When glycerol esters of fatty acids are used, the foam former can suitably be compounds such as glycerol monostearate and/or glycerol monooleate. Polyglycerol esters can be prepared by polymerizing glycerol, preferably under alkaline conditions, and subsequently reacting them with certain fatty acids. Suitable polyglycerol esters can be hexaglycerol monooleate, octaglycerol monostearate and/or octaglycerol monooleate. The sorbitan esters of fatty acids used in certain embodiments of the invention may be sorbitan monostearate, sorbitan monooleate and/or sorbitan monopalmitate. Additionally, any possible combination of compounds belonging to the above classes can be used.

The method is characterized in that the mixture is aerated after addition of the foam stabilizer and sodium bicarbonate and/or after cooling of the mixture. This does not exclude that other venting steps are performed, and according to certain embodiments one, two or preferably all of the optional venting steps are performed in the method. It is also not excluded that aeration has already been carried out in connection with the mixing and/or addition steps.

The method of aeration is not particularly limited and can be introduced into the mixture, bubbled through the mixture, etc., e.g. air injection, air whipping in - e.g. large enough paddle/shuffle and/or mixing with sufficient paddle motion and/or a sufficient lower speed. For example, aeration can be achieved using a thorough mixing machine similar to a mixer for preparing mousses, such as the Krups Prep & Cook HP 5031 Mousse Whisk Shuffle, and/or using an aerator, such as a Mondomix aerator. It can be carried out by injection of air. Aeration can be carried out at any suitable temperature, such as room temperature (approximately 20-24° C.), 30-80° C., such as 35-75° C., preferably 30-60° C., inclusive. The method does not exclude that aeration is performed incidentally to the mixing of the components and/or in the step of adding the components, for example when frothing is used.

In the present invention, an aerosol forming agent, a foam blowing agent, a foam stabilizer, a tobacco-containing agent, an inhalable agent, at least one non-tobacco flavorant, sodium bicarbonate and a solvent to form an aerosol-generating foam such as is not particularly limited. Furthermore, the gas used for ventilation is not particularly limited and may be air, for example. Further ingredients can also be mixed. However, according to certain embodiments, essentially no further components or further components are combined.

Propylene glycol for use in the present invention should be understood to be propane-1,2-diol. Glycerin or glycerol for use in the present invention should be understood to be 1,2,3-propanetriol.

The aerosol-forming agent can further contain water. However, according to certain embodiments, no water is included because water in aerosol form can burn the user's mouth. Water may be included in an amount of 0-15%, such as 5-10% by weight of the foam.

Example 1
In the following, the invention will be described in detail in connection with these embodiments. However, these examples are for illustrative purposes and are not intended to limit the scope of the invention.

Table 1 shows that tobacco mousses containing various percentages of sodium bicarbonate were investigated. To make an exemplary foam, the ingredients shown in each column of Table 1 were mixed and combined as follows.

First, propylene glycol, glycerin and purified water were whipped and aerated using a Krups Prep & Cook HP5031 mousse whipping shuffle at 45°C for 5-10 minutes. When whipping the mousse, the speed should be adjusted so that there is a noticeable increase in volume and small bubbles appear and some remain in the foam. If the whipping is too rapid, mixing will prevail and the foam structure will tend to collapse and thus return to being fluid. One option is to start lathering slowly and slowly increase the lathering rate as the foam begins to develop a lighter, more mousse-like texture; If you notice that it seems to be getting better, slow down by about 10%. Rapid cooling with ice or cold water can be recommended to maintain the foam structure to create a stable portion. Using the Krups device described above, best results can be obtained at speeds of 60-200 rpm. Following the above description, a person skilled in the art can make adaptations within the scope of his knowledge.

In the next step, gum was added and the mixture was whipped and aerated for 5-10 minutes. Tobacco powder was then added and frothing and aeration was carried out for 5-10 minutes. Binder was added and the mixture was again whipped and aerated for 5-10 minutes. Sodium bicarbonate with the desired percentage was then added and the mixture was again whisked and aerated for 5-10 minutes. Finally, the mixture was cooled to 10°C within 10 minutes and aged at 45°C or room temperature for 8 hours.

The results obtained from Example 1 are shown in Table 2. Samples 2, 3 and 4 with sodium bicarbonate in the mixture showed higher pore volume or permeability values compared to the control sample (Sample 1). Sample 3 containing 1% sodium bicarbonate showed the greatest increase in pore volume (12%). However, it was observed that a higher percentage (2%) of sodium bicarbonate in the mixture did not give the higher than expected aeration values. For this reason, it is preferred to have no more than 1% sodium bicarbonate in the foam mixture.

In general, samples 2 and 3 achieved good puff impact and smooth, refined tobacco sweetness when heated to the first dry puff using an aerosol generator at 245°C for 20 seconds, whereas sample 3 , achieved a slightly higher sweetness and had a higher impact compared to sample 2.

Maximum binding force can be generated by appropriately increasing the reaction time towards thermodynamic equilibrium. The time to achieve equilibrium is determined primarily by kinetic effects that appear to be product temperature dependent in the aging and binding process steps. The temperature setting can also relate to the level of flavor volatility to maintain suitable tobacco mousse heating properties. For example, vapor release and flavor release, etc., produce distinct flavors and odors.

Example 2
The method was performed as in Example 1, except that the mixing and aerating steps were performed at 3,000 rpm using a Mondomix aerator. Again, 5-20% aeration was achieved. Also venting at an increased pressure of 2.5 bar as counterpressure (30 mmVA) did not increase this level.

Examples 3 and 4
Samples 2 and 3 as in Example 1 were prepared in the same manner except that sodium carbonate was added into the foam instead of sodium bicarbonate, e.g., with a correspondingly reduced amount of tobacco. Manufactured by Compared to samples 2 and 3 in Example 1, lower air permeability values (6% and 8% respectively) were achieved.

Claims (14)

A method of forming a foam for an aerosol-generating article comprising:
- mixing an aerosol-forming agent, a foam-forming agent and optionally a solvent and/or at least one non-tobacco flavorant, preferably under heating;
- adding a tobacco-containing agent and/or an inhalable agent to said mixture;
- adding a foam stabilizer;
- cooling the mixture;
the mixture is aerated after addition of the foam stabilizer and/or after cooling of the mixture;
and sodium bicarbonate is added to said mixture prior to cooling said mixture, said sodium bicarbonate content being less than 1% by weight based on the total weight of said foam. 3. The method of claim 2, wherein the sodium bicarbonate content is about 0.25% to 0.75% by weight, based on the total weight of the foam. 3. A method according to claim 1 or 2, further comprising adding a binder to said mixture, preferably before said aeration step. 5. The method of claim 4, wherein the binder content is less than 15% by weight, based on the total weight of the foam. Process according to any one of the preceding claims, wherein the foam stabilizer has a viscosity of 300 mPas to 3,000 mPas, preferably 400 mPas to 2,500. The foam former has a gel strength of 300 g/cm ³ to 3,000 g/cm ³ , preferably 400 g/cm ³ to 2,500 g/cm ³ ,
and/or the foam former has a viscosity of 300 mPas to 3,000 mPas, preferably 400 mPas to 2,500 mPas. below:
- a foam comprising a tobacco-containing and/or inhalable agent, an aerosol-forming agent, a foam-forming agent, sodium bicarbonate and a foam stabilizer,
- the weight of said tobacco-containing agent and/or said inhalable agent is between 0.1 and 33% by weight of said foam;
- the weight of said aerosol forming agent is between 10 and 80%, preferably between 40 and 70% by weight of said weight of said foam;
A foam, wherein the weight of said sodium bicarbonate is less than 1% by weight, based on said total weight of said foam. 9. The foam of claim 8, wherein said weight of said sodium bicarbonate content comprises 0.25% to 0.75% by weight. 10. Foam according to claim 8 or 9, wherein the foam has a pore volume of at least 5% by volume, preferably 12-20% by volume, based on the total volume of the foam. 11. Any one of claims 8-10, wherein the foam-forming agent is a protein-free polysaccharide and the weight of the foam-forming agent is less than 20% by weight of the total weight of the foam. Foam as described. of claims 8-11, further comprising a solvent, preferably water, and/or an acid and/or an ester, in an amount up to 15% by weight, preferably up to 5% by weight, based on the total weight of the foam. A foam according to any one of the clauses. A foam according to any one of claims 8 to 12, wherein the foam is an open pore foam. at least 20% of the cells in said foam have a diameter between 25 μm and 50 μm, and/or at least 15% of said cells have a diameter between 51 μm and 100 μm, and/or at least 11% have a diameter between 101 μm and 171 μm;
The foam according to any one of claims 8-13. Claims 8-, further comprising a binder, said binder being preferably added before said aeration, and the content of said binder being less than 15% by weight, based on said total weight of said foam. 15. The foam according to any one of 14.