Technical field of the invention

The present invention relates to an aerosol-generating substrate and its manufacturing method. The invention also relates to an aerosol-generating article comprising the aerosol-generating substrate, wherein the aerosol generating substrate is provided in form of a semi-solid matrix.

Background of the invention Different kinds of aerosol-generating articles and devices for use therewith as an alternative to cigarette smoking have been mushrooming and have been made commercially available on the market over the last decade. These include regular e-cigarettes which generate an inhalable, usually flavoured, aerosol or vapour from electrically heated liquid(s) contacted with a heating element powered with a battery.

Another common alternative consists in heat-not-burn aerosol generating articles comprising an aerosol-forming substrate, which is resistively or inductively heated at a rather relatively low temperature, for instance below 350 °C, to avoid combustion thereof. A charge of inhalable aerosol can then be released from the aerosol-generating article. The aerosol released is originated from the aerosol formers, which are incorporated into the tobacco material.

The tobacco material typically used in such heat-not-burn aerosol generating articles are made of reconstituted tobacco (Recon or RTB) for instance. The Recon can be defined as a tobacco material in sheet shape which is acquired by collecting the remnants of tobacco leaf, dust, stem or other relevant parts after the processing procedure. Patent application EP3528652 relates to a new form of aerosol generating substrate, wherein the substrate is provided in form of a mousse. Such form of an aerosol-generating article is described to be advantageous as it provides a more uniform heating, a good quality aerosol, and extremely efficient extraction of the tobacco ingredient containing agent and/or the inhalable agent. However, due to its non-solid form, it is noticeable that the flavour is lost very quickly, hence rendering an overall low smoking experience to the users.

Patent application US 20190261685 relates to an aerosol-generating substrate for use in an aerosol source member. The substrate may comprise a fibrous filler material, an aerosol forming material, and a plurality of heat- conducting constituents. The substrate may be formed as a sheet, and the heat conducting constituents may be part of the sheet. Flavourant may also be provided to the aerosol generating substrate.

Patent application W003009711 relates to another method which aim to increase or alter the flavour strength and intensity. It was proposed therein that a capsule containing flavourant is placed in the filter portion. When the capsule is pressed, the capsule bursts and discharges the aromatic material into the filter in order to change a taste of the tobacco.

It would therefore be desirable to provide a solution to overcome the above-mentioned problems as well as to provide an alternative which is able to deliver a more pleasant smoking and/or vaping experience.

In a further aspect, it is also the aim of the present invention to provide a solution for improving the sensory properties of the above-mentioned consumables. Summary of the invention

The inventors of the present invention have found solutions to the above-discussed problems and propose, in a first aspect of the invention to provide an aerosol-generating article comprising a foamed tobacco-containing aerosol-generating substrate and a plurality of non-tobacco granulated flavour particles incorporated into the aerosol-generating substrate.

A second aspect of the invention relates to the provision of an aerosol generating article comprising a tobacco-containing portion and a filter portion, wherein the tobacco-containing portion comprises the aerosol-generating substrate as previously defined.

A third aspect of the invention provides a method of preparing an aerosol-generating substrate, comprising the steps of: (a) Providing a mixture comprising one or more components selected from the list consisting of propylene glycol, 1, 3-Propanediol, glycerol, water, gum and binder; (b) Mixing the mixture; (c) Providing tobacco-containing material into the mixture; (d) Mixing the mixture; (e) Providing a plurality of granulated flavour particles into the aerosol-generating substrate; (f) Mixing the mixture.

The inventors have found out that the aerosol-generating article according to the present invention, thanks to the granulated flavoured particles (e.g. non-tobacco), can offer a consistent flavour delivery over a typical use of a heat-not-burn consumable article, i.e. for an average 12 to 20 puffs smoking experience. Although the aerosol-generating article is provided in a semi-solid matrix i.e. foam, as the granulated flavoured particles comprises a “shell-like” hardened surface, a prolonged period of flavour release can be ensured, hence the favoured flavoured is consistent throughout the entire smoking experience to the contrary of the prior art articles where the flavour depletes typically after the first few puffs.

The granulated flavour particles described herein referred to tobacco- containing and/or non-tobacco granulated flavour particles. In other words, the flavoured particles may comprise particles with or without tobacco/nicotine flavouring.

According to some embodiments, up to about 10.0 wt. % of the total weight of the aerosol-generating article are the granulated flavour particles. The granulated flavoured particles can be evenly or randomly distributed within the substrate. In such cases, usually around 5.0 wt. % of granulated flavoured particles (from the total weight of the aerosol-generating substrate) are enough to render a consistent flavour release throughout

To this end, in embodiments where the granulated flavoured particles are distributed in a gradient manner, highest concentration (or density) of the granulated flavoured particles are arranged closer to the longitudinal central axis than the periphery area of the tobacco-containing portion. Such arrangement of the granulated flavoured particles allows a consistent and prolonged release of flavour over time to the end of vaping session. For instance, an increasing gradient density of the granulated flavour particles can be provided to the aerosol generating substrate, with a density from 0.01 g/cm ³ at the periphery area of the aerosol-generating article, increasing for example step-wise to about less than 2.0 g/cm ³ towards the longitudinal central axis of the aerosol-generating article. Such arrangement of granulated flavoured particles is particularly advantageous for aerosol-generating device having an oven-like heating chamber, wherein the tobacco-containing portion of the aerosol-generating article is heated externally at the outer surface instead of internally.

It is noted also that an even distribution of granulated flavour particles renders less significant result compared to the aforementioned increasing gradient density distribution of granulated flavour particles, as the even distribution of granulated particles does not always guarantee a consistent flavour delivery i.e. from the first puff to the last puff.

In an embodiment, the aerosol-generating substrates can be provided in at least two steps, wherein in the first step, aerosol-generating substrate containing higher density (or concentration) of granulated flavoured particles can be provided as a first layer followed by a second layer of aerosol-generating substrate, which contains lower concentration of granulated flavoured particles. This allows a gradient of increasing concentration of granulated particles towards the longitudinal axis (central axis) of the aerosol-generating article, thus allowing a consistent and prolonged release of flavour over time to the end of vaping session.

According to some preferred embodiments, the granulated flavour particles are provided in the aerosol-generating article with a density of less than 2.0 g/cm ³ , preferably less than 1.0 g/cm ³ , preferably less than 0.5 g/cm ³ , or more preferably between 0.01 g/cm ³ and 0.1 g/cm ³ . In some embodiments, the granulated flavour particles are provided ranging from between 2.0 wt. % and 10.0 wt. % of the total weight of the aerosol generating substrate, preferably between 2.5 wt. % and 8.0 % of the total weight of the aerosol-generating substrate, preferably between 3.5 wt. % and 7.0 % of the total weight of the aerosol-generating substrate, most preferably between 4.5 wt. % and 6.0 % of the total weight of the aerosol-generating substrate.

In some embodiments, the granulated flavour particles have a mean diameter of between about 0.1 mm and about 3 mm, preferably between about 0.5 mm and about 2 mm, or more preferably around 1.5 mm.

In some embodiments, the granulated flavour particles comprise a gel of a polysaccharide. For instance, the granulated particles comprised a flavour that is coated with a polysaccharide without adding any gelling agent, such as a metal chloride, to the material.

In some examples, it has been noticed to be effective that a flavour and a polysaccharide are sufficiently kneaded and emulsified in a heated aqueous solution, and the emulsified state that the flavour coated with the gelled polysaccharide is present in the aqueous solution is maintained while the flavour- containing material is prepared.

In yet some embodiments, the granulated flavour particles comprise a gel of a polysaccharide containing no gelling agent. Thus, an unfavourable decomposed product of the chloride is not produced in the mainstream smoke during smoking.

According to some embodiments, the aerosol-generating substrate/article further comprises one or more components selected from the group consisting of propylene glycol, 1, 3 propanediol, glycerol, water, gum, flavourant, additives, nicotine and binder.

According to some embodiments, the aerosol-generating substrate/article comprising the granulated (non-tobacco) flavour particles are provided in an increasing gradient density towards the longitudinal central axis of the aerosol-generating article. This renders the aerosol-generating articles a better flavour-retaining property. A more consistent and prolonged flavour delivery throughout the entire vaping process (e.g. approximately 15 puffs) was observed.

It is disclosed herein that the semi-solid matrix of the aerosol- generating substrate may be in form of a foam, a mousse, a gel or a viscous liquid.

According to yet some embodiments, the aerosol-generating article comprises a tobacco-containing portion comprising the aerosol-generating substrate and a filter portion. According to yet some embodiments, the present invention further comprising a step of providing gums to the mixture before the step (e) i.e. providing a plurality of granulated flavour particles into the aerosol-generating substrate. The gum gives a good binding property.

According to yet some embodiments, the mixture is constantly mixed for a certain amount of time and heated slightly at above room temperature in each step.

According to yet some embodiments, the mixture is constantly mixed for at least 6 minutes and/or is heated at approximately 45 °C and/or is aerated. According to some preferred embodiments, the method further comprising a step of providing a first layer of aerosol-generating substrate encircled by a second layer of aerosol-generating substrate, wherein the first layer has a higher volume and/or density of granulated flavour particles than the second layer. Such a method allows an increasing gradient density of the granulated flavour particles to be provided to the aerosol-generating article.

Brief description of drawings

Figure 1 shows a side view of an aerosol-generating article of the present invention.

Figure 2 shows a cross section view from point W of the Figure 1.

Figure 3 illustrates the comparison of flavour delivery of aerosol generating substrate with or without granulated flavour particles.

Detailed description of the invention

Figure 1 shows a side view of an aerosol-generating article 100 according to the first embodiment of the present invention. The aerosol generating article 100 comprises a filter portion 10 and a tobacco-containing portion 20. The elongated cylindrical article 100 comprises a longitudinal central axis X. Aerosol-generating substrate 24 that is provided in a semi-solid matrix comprising granulated flavour particles are provided in the tobacco-containing portion 20.

Figure 2 shows a cross section view at point W as shown the Figure 1 where the cross section was sectioned in the tobacco-containing portion 20. The aerosol-generating article 100 comprises a central axis X. Aerosol-generating substrate 24 that is provided in form of semi-solid matrix comprises a plurality of granulated flavour particles 22. The granulated flavour particles 22 can be randomly distributed within the tobacco-containing portion 20 to have an evenly distributed profile or can be distributed in an increasing gradient density towards the central axis, as shown in the Figure 2.

The inventors of the present invention discovered that although aerosol-generating substrate 24 provided in form of a semi-solid matrix such as tobacco mousse is superior to standard reconstituted tobacco (e.g. more uniform heating, a good quality aerosol, and extremely efficient extraction of the tobacco ingredient containing agent and/or the inhalable agent), its non-solid form, induces fast disappearance of the top flavours used in the tobacco recipe within the first few puffs of consumption, hence affecting negatively the overall smoking experience.

The invention provides a solution to compensate for the fast flavour disappearance experienced with semi-solid matrix aerosol-generating substrates by the introduction in the substrate of flavour particles in granulated form. For the avoidance of doubts and full clarity of the present disclosure, the terms “granulated particles” shall not be construed limitedly to only regular, rounded, granules of flavoured material but shall be understood in the context of the present invention as particles of a substantially 3-dimensional shape, such as irregular granules or flakes. Flence, the granulated flavour particles can be small pieces of flavoured sheet that is flavoured encapsulated. The particles can be provided by cutting or shredding sheet of flavoured material into fine pieces or particles, where the dimension of the particles can be adjusted accordingly. The granulated flavour particles 22 can then be added to the semi-solid matrix (e.g. mousse) substrate recipe to avoid quick flavour release so that consistent gradual release of flavour during vaping process can be ensured. To this end, it is disclosed that the granulated flavour particles 22 can be added in the end of the mixing process to minimize flavour loss.

The granulated flavour particles 22 can be obtained through any conventional methods within the common general knowledge of a skilled person. As an example, a flavour can be coated with a polysaccharide, with or without adding any gelling agent, such as a metal chloride, to the material. Alternatively, a combination of polysaccharide and one or more flavouring materials can be used to provide the granulated flavour particles 22. The polysaccharide serves as a substrate is found to be an excellent medium to carry the flavouring ingredients. The granulated flavour particles 22 can be provided having a mean diameter of between about 0.1 mm and about 3 mm, preferably between about 0.5 mm and about 2 mm, or more preferably around 1 mm.

It is however noted that in the process of preparing the granulated flavour particles, extremely high temperatures e.g. higher that 85 °C should be avoided in order to preserve the flavour. Flavours tend to be lost or turn weaker on such high temperatures. For this reason, the granulated flavour particles are only introduced into the mixture in the last (or second last) step in order to maximally preserve its flavour.

The granulated flavour particles 22 proposed in the present invention can be provided in any kind of flavour that is permitted in the tobacco industry. Typical flavours are for instance fruity, berry, menthol, wood, chocolate, tobacco etc.

In some examples, it was found out that the polysaccharide used in the invention can be gelled by applying heat. Thus, no gelling agent is required. Accordingly, the granulated flavour particles 22 according to the invention contains no gelling agent such as a metal chloride. Thus, for example, an unfavourable decomposed product of the chloride is not produced in the mainstream smoke during smoking.

In order to increase the flavour content of the granulated flavour particles, it is necessary that the flavour is effectively blended or coated with the polysaccharide. The present inventors have found that it is effective that a flavour and a polysaccharide are sufficiently kneaded and emulsified in a heated aqueous solution, and the emulsified state that the flavour coated with the gelled polysaccharide is present in the aqueous solution is maintained while the granulated flavour particles are prepared. That is, in granulated flavour particles that can be sufficiently kneaded and emulsified and can keep the emulsified state, high flavour content can be finally obtained. On the other hand, it has been found out that, in a system that cannot keep the emulsified state in the aqueous solution during the preparation of the material even when sufficient kneading and emulsifying are performed, high flavour content cannot be attained. The granulated flavour particles 22 of the invention may contain for instance 18 wt. % or more, preferably 60 wt. % or more, more preferably 70 wt. % or more of flavour. In other words, these numbers represent the granulated (or encapsulated) flavour contains this amount of flavour in it by weight.

As an example, the polysaccharide that can keep an emulsified state as described above is preferably a single component system of carrageenan, agar, gellan gum, tamarind gum, psyllium seed gum or konjak glucomannan, or a composition system of combined two or more components selected from the group consisting of carrageenan, locust bean gum, guar gum, agar, gellan gum, tamarind gum, xanthan gum, tara gum, konjak glucomannan, starch, cassia gum and psyllium seed gum. At the time of the emulsification, it is preferred to use an ordinarily used emulsifier, such as lecithin, together.

Preferably, the granulated flavour particles 22 are provided in an increasing gradient density towards the longitudinal axis X compared to being evenly distributed within the aerosol-generating substrate 22. Higher density of granulated flavour particles 22 in the central position permits consistent and prolonged flavour delivery, as will be discussed below, see for instance Sample 1 of Figure 3 where the granulated flavour particles 22 are distributed in an increasing gradient density towards the longitudinal central axis X.

Examples

The present invention will now be described in detail with reference to examples thereof. However, these examples serve merely as illustrative purpose and do not limit the scope of the invention.

Example 1 k-Carrageenan (CARRAGEENAN CS-530, San-Ei Gen F.F.I., Inc.), which is extracted from red algae seaweed was selected as a single polysaccharide and l-menthol (special grade, Wako Pure Chemical Industries, Ltd.) was selected as a flavour, respectively. The granulated flavour particles for aerosol-generating substrate of Example 2 was prepared by the following procedures.

To each 5 g of k-carrageenan about 100 mL of water was added, which was then heated in a thermostat bath of 80°C to dissolve k-carrageenan sufficiently in water. A total of 25 g of menthol (TEG-10374410) and 2 mL of a 5% aqueous solution of lecithin (Sunlecithin A-1 , Taiyo Kagaku Co., Ltd.) were added thereto, which was sufficiently emulsified by means of a homogenizer (high performance mixer DMM, ATEC Japan Co., Ltd.). This emulsified slurry was turned into a granulated form, which was dried in a forced air circulation dryer of 40°C for one week. The granulated flavour particles were provided having a mean diameter of about 1.5 mm. Samples 1 and 2 comprise such granulated flavour particles.

Example 2

Table 2 shows an example ratio of the tobacco mousse with or without granulated flavour particles. For producing exemplary aerosol-generating substrate 24 (Samples 1 , 2 and 3) as shown in the Figure 3, the ingredients given in the respective column of Table 2 were mixed and combined as follows. It is noted herewith that the flavour of Sample 1 and Sample 2 are provided as granulated flavour particles (as explained in the Example 1) whereas the menthol flavour of Sample 3 was not provided as a granulated form but the menthol flavour is provided directly from a liquid mixture and is subsequently blended with the tobacco mousse, forming the Sample 3.

Table 2: Aerosol-generating substrate with (Samples 1, 2) or without (Sample 3) granulated flavour particles.

The propylene glycol, the glycerine and the purified water were whipped and aerated for 5-10 min at 45°C using a Krups Prep & Cook HP5031 mousse whipping shuffle, preferably at speed “6”. When whipping up the mousse, the speed can 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’s knowledge in accordance with the above description.

In a next step (within 1 minute of the previous step), the gum was added, and the mixture was whipped and aerated for 5-10 minutes, preferably at 6 min, at 45°C using a Krups Prep & Cook HP5031 mousse whipping shuffle, with the same speed. Afterwards the tobacco powder was added and whipping, and aeration were carried out for 5-10 min, preferably at 6 min, at 45°C with the same method.

Next, the granulated flavour particles were added followed by the binder (within 1 min), and the mixture was again whipped and aerated for 5-10 min, preferably at 6 min, at 45°C with the same method. Finally, the mixture was placed in an oven at 50 °C for approximately 18 hours before is ready to be packed and be used.

Figure 3 illustrates the perceived intensity of menthol flavour in smoke (in percentage) during sensory testing of three different types of aerosol- generating articles as explained above.

Both the Sample 1 and Sample 2 comprise granulated flavour particles 22 whereas the Sample 3 does not comprise such granulated flavour particles. The granulated flavour particles 22 of Sample 1 were distributed in an increasing gradient density towards the longitudinal central axis as shown in the Figure 2 whereas in the Sample 2, randomly distributed granulated flavour particles 22 were provided to the aerosol-generating substrate 24. The result showed that the Sample 1 and the Sample 2 have higher flavour-retaining property than the Sample 3 throughout the vaping process (from puff 0 to puff 14).

Surprisingly, when the granulated flavour particles are distributed in an increasing gradient density towards the central axis X, a consistent and higher flavour delivery was observed throughout the vaping process. In other words, Sample 1 rendered the most consistent flavour delivery throughout the entire vaping process.