WO2023083962A1

WO2023083962A1 - Surface treatment for tobacco material

Info

Publication number: WO2023083962A1
Application number: PCT/EP2022/081469
Authority: WO
Inventors: Daniel Lickefeld
Original assignee: Jt International Sa
Priority date: 2021-11-10
Filing date: 2022-11-10
Publication date: 2023-05-19

Abstract

The present invention relates to an aerosol generating product for use in an aerosol generating article. The aerosol generating product is arranged in a filter section of the aerosol generating article and interacts with a vapor flow which is generated in an aerosol generating section of the article. The generated vapor flows along a flowpath from the heated aerosol generating section to the filter section. The aerosol generating product comprises at least one core which modifies the properties of the vapor. The aerosol generating product further comprises at least a first and a second flavoured layers which are coated onto the common core. The first and the second layers are dissolvable by a moisture comprised in the vapor flow one after another thereby modifying the vapor with a first and a second flavouring. The invention relates also to a method for manufacturing such an aerosol generating product.

Description

Surface treatment for tobacco material

Description

The present invention relates to an aerosol generating product comprising at least a first and a second flavoured layers which are coated onto a common core, wherein the first and the second layers are dissolvable by a moisture comprised in the vapor flow one after another thereby modifying the vapor with a first and a second flavouring successively. The invention also relates to a method for manufacturing such as an aerosol generating product.

The taste of the usual smoking articles which contain smokable substances, such as tobacco, can be modified by flavourings as additives which enhance the vapor during the smoking session. This can be achieved through various flavoring devices for enhancing the taste of the smoking articles. For example, there are multi-stage flavorant delivery systems known which can achieve enhancing the vapor by users actuating with different flavourings, as described in US10893700. Such delivery system mostly comprises at least a first encapsulated flavour being releasable by pressure and second encapsuled flavouring being heat sensitive. The capsules mostly comprise liquid or gel based flavouring compositions which can be released during the smoking session. However, there is a risk of cross-contamination of different tastings for example after pressing the pressure sensitive capsule prematurely, the user may suffer an unpleasant resulting taste. The user must therefore intuitively find a moment for the first flavouring substance to stop flavouring the vapor in order to crush the second capsule.

There exists also aerosol generating articles comprising two or more different flavoringrelease additives having different flavoring release temperatures are located at different locations in an electrically heated cigarette that reach different temperatures from each other. However, again there is a risk of cross-contamination. Moreover, the proper positioning of the different flavoring-release additives complicates the manufacturing of the article.

It is therefore the objective of the invention to provide an aerosol generating product which reduces or prevents a cross-contamination of several tastings during the smoking session. Preferably such aerosol generating product comprises a self-regulating flavor delivery for different flavourings. Furthermore, the objective of the invention is also to provide a method of manufacturing the mentioned aerosol generating product.

The above-mentioned requirement is met by the object of claim 1. Preferred embodiments are objects of the dependent claims.

An aerosol generating product for use in an aerosol generating article, wherein the aerosol generating product is arranged in a filter section of the aerosol generating article for interacting with a vapor flow which is generated in an aerosol generating section of the article. Preferably the aerosol generating article is selected from the group of consumables such as cigarettes or Heat not Burn articles. Thus, the aerosol generating section may comprise tobacco substrates such as tobacco leaves, reconstituted tobacco or other heatable or combustible products which comprise at least nicotine. During heating the aerosol generating section of the article generates inhalable aerosol, vapor or smoke which comprises at least a residual amount of moisture. In the following, only vapor is mentioned. However, this is not intended to be restrictive, but merely serves to simplify matters.

The generated vapor in the aerosol generating section of the article flows along a flowpath from the heated aerosol generating section to the filter section during use of the aerosol generating article. The filter section may be divided into at least two compartments. Preferably at least one compartment in the filter section comprises a fibrous filter material such as cellulose acetate or paper fibre. Also preferably another compartment in the filter section comprises a cavity which may be filled with filtering granules such as charcoal granules.

It is conceivable that the vapor passes further sections of the article during the use. Thus, the aerosol generating article may further comprise a cooling section through which the vapor moves from the heated aerosol generating section to the filter section and finally into the mouth of a consumer. For example, the cooling section is formed of a hollow tube, a tube containing cooling substrate (e.g., polylactic acid) or a hollow filter segment or combinations thereof.

The aerosol generating product comprises at least one core which modifies the properties of the vapor. It is conceivable that the core is selected of the group of organic or non-organic materials suitable for use in the aerosol generating article, such as granules with solid or liquid structure. The granules might be made of tobacco material, flavor capsules, charcoal or a combination of at least the mentioned materials.

According to one aspect of the invention, the aerosol generating product comprises at least a first and a second flavoured layers which are coated onto the common core. The first and the second layers are dissolvable by a moisture comprised in the vapor flow one after another thereby modifying the vapor with a first and a second flavouring.

It is also conceivable to coat more than two flavoured layers onto the core, for example three or four layers with different flavourings. However, the more layers with different flavorings are used, the longer the consumer may enjoy successive changes in taste. This taste variation during one smoking session provides a continuous pleasant smoking experience. Due to the dissolution in sequence of the flavoured layers, the risk of cross-contamination of the several flavourings is successfully reduced or prevented.

In the preferred embodiment, the aerosol generating product is fully encased or coated with the dissolvable layers. This has the advantage that it does not matter how the product is inserted into the article because the coated areas might interact with the vapor flow in any case.

The dissolvable flavoured layers might comprise an aerosolisable carrier material or humectants selected of the group of water dissolvable materials selected amongst the group of: glycerol (glycerin), glycol ether such as propylene glycol, 1,3-butanediol, sorbitol, esters of polyhydric alcohols, triethyl citrate (TEC), or triacetin and combinations thereof. The aerosolisable carrier is vaporized upon heating, generally at a temperature of about 350°C or lower.

Alternatively or additionally the flavoured layers comprise sugar solution, coloring agent, aroma additives and/or sweetener. Due to this, it is possible to provide an aerosol generating product with several flavours such as double apple, coffee, lemon, menthol, peppermint, vanilla, black tea or others at the same smoking session. Furthermore, it is conceivable that the dissolvable layers comprise tobacco particles and/or nicotine additives which could significantly improve the tobacco taste or nicotine content of the inhalable vapor.

According to another embodiment, the first and second flavour layers are separated by a protective layer preventing thereby flavour cross-contamination between the flavour layers. Preferably the protective layer comprises a flavor neutral or low intensity flavor binder material which is dissolvable by the moisture comprised in the vapor. Applying the protective layer between the first and the second layer is particularly advantageous for separating especially intense flavours, for example such as peppermint or coffee.

Additionally or alternatively, the aerosol generating product comprises two or more protective layers which are successively applied between the flavoured layers. Thus, it is possible to coat the core sequentially with the first flavoured layer, a first protective layer, the second flavoured layer, the second protective layer and a third flavoured layer. This allows several flavours to be neatly separated from each other.

According to another embodiment, the protective layer is a sugar-based or starch layer. The protective layer comprising sugar and/or starch preferably further comprises coloring agents or other non-aromatised additives. Such non-aromatised aditives are preferably selected from the group of humectants with hydrophilic character, such as glycerin or sorbitol.

According to another embodiment, the protective layer is non-flavoured. As the protective layer is preferably odourless and tasteless, it does not change the properties of the vapor during the dissolution. Thus, the consumer can enjoy preferably the unflavoured generated vapor for a short period of time before the second flavor appears. This can create a smooth transition between several flavours allowing the consumer not to be irritated by the sudden changes in taste and slowly adapt to a new taste experience during the smoking session.

According to another embodiment, each coated layer has a thickness between 10 microns and 1000 microns. It is also conceivable that the protective layer comprises a lower thickness than the flavoured layers. In this case the flavoured layers might comprise a thickness in a range of 100 microns and 900 microns, preferably 500 microns and 1000 microns. Preferably the protective layer comprises the thickness in a range of 10 microns and 100 microns, preferably in the range of 30 microns and 80 microns.

According to another embodiment, a plurality of cores is formed of granules of tobacco substrate and/or charcoal being arranged in the filter section or in a cavity section or heated aerosol generating section. Preferably the cavity section is the cooling section or a part of the cooling section of the aerosol generating article. Also preferably the cooling or cavity section is connected to the filter section and the aerosol generating section. Alternatively or additionally the cavity section may be the compartment of the filter section. In this case, it is conceivable that the cavity is surrounded by at least two further filter compartments or is connected to the aerosol generating section of the article.

The plurality of cores may comprise at least one capsule filled with a flavouring liquid and at least one core with a solid structure. The capsule may comprise the liquid tobacco substrate. Such tobacco substrate preferably comprises tobacco particles and/or other organic flavour enhancer. Preferably the core with the tobacco substrate is arranged in the filter section of the aerosol generating article. Also preferably, the core with the solid structure is arranged in the cavity section of the aerosol generating device.

The combination of the coated capsule and charcoal with at least two flavoured layers may deliver an option for the consumer to enrich the vapour with the second flavouring at a time he has chosen. Thus at least one flavoured layer or protective layer coated on the solid cores, preferably charcoal, may be dissolvable by the liquid comprised in the capsule. In this case, it is conceivable that at least one flavoured layer is dissolvable by the vapour. After dissolving of the flavoured layer, the consumer may activate the capsule, preferably by applying pressure to the capsule, to dissolve the protective layer. After dissolving the protective layer, the second flavoured layer may interact with the vapour and modify the vapour with another flavouring. This combination assumes that the capsule preferably comprises a predefined discharging direction. Also preferably, the discharging direction of the capsule opposes the vapour flow and/or runs along the flow path.

It is conceivable that a plurality of charcoal as the plurality of cores is comprised in the aerosol generating section of the article. In this case, it is conceivable that the flavoured layers and/or the protective layer comprise a material which interacts with the uncooled vapour flow. However, it has been found that the heated flavoured layers which interact with vapour in the aerosol generating section may unfold more intense aroma.

According to another embodiment, the plurality of cores comprises an aerosol former, wherein the aerosol former comprises at least one of the following ingredients: water, monovalent alcohols, polyvalent alcohols, sugar alcohols, sugars and/or polyvalent alcohol esters. The aerosol former is preferably selected from the commonly used aerosol former in the tobacco industry, e.g. glycerol (glycerin), propylene glycol, 1 ,3-butanediol, esters of polyhydric alcohols, triethyl citrate (TEC), or triacetin and combinations thereof. The plurality of cores or at least one core of the aerosol generating product preferably comprises an amount of the aerosol former in a range of 5 percent and 25 percent, preferably in range of 10 percent and 20 percent, also preferred in range of 12 percent and 18 percent, by weight on a dry weight basis of the aerosol generating product.

According to another embodiment, the plurality of cores comprises a binder such as gums, starch, cellulose derivatives or combinations thereof. Preferably the binder is selected from a group of consisting of alginates, pectins, starches (and derivatives), celluloses (and derivatives), gums, silica or silicones compounds and combinations thereof. Preferably, the binder is selected amongst the group of: guar gum, acacia gum, carboxymethylcellulose (CMC), hydroxypropyl cellulose (HPMC), hydroxyethyl cellulose, gellan gum, . Preferably the plurality of cores or at least one core of the aerosol generating product comprises an amount of the binder in a range of 3 percent and 30 percent, preferably 8 percent and 20 percent, also preferably 10 percent and 15 percent, by weight on a dry weight basis of the aerosol generating product.

According to another embodiment, the core or each of the plurality of cores has a maximum dimension or diameter between 100 and 1000 microns. In particular the plurality of cores may comprise a uniform size. Preferably the core as the with liquid filled capsule comprises a volumetric capacity in range of at 0.3 ml and 0.8 ml, preferably 0.4 ml and 0.6 ml. The capsule preferably comprises a maximum diameter of at least 3 mm.

According to another embodiment, the core comprises agglomerated tobacco powder having a median diameter of the particle size distribution (D50) equal to or smaller than 50 microns, preferably equal to or smaller 30 microns. Preferably the core is coated by the flavoured layer comprising the tobacco powder. Tobacco particles having such a small median diameter provide a high surface area when contacted by the passing vapour. This allows transfer of the molecules from the particles into the vapour flow at least during the dissolving of the flavoured layer. The particle diameter of < 30 pm has been found to allow transfer of a plurality of flavoring molecules, which contribute to a full tobacco flavor. Also nicotine could pass over from the tobacco particles to the vapour in a similar way. Since nicotine has a flavour and is usually a constituent of tobacco, the term “flavoring molecules” may also include nicotine.

According to another embodiment, the core is a capsule comprising a breakable shell and an inner flavouring liquid, wherein the liquid modifies the vapor with a third flavouring. Preferably the shell of the capsule is pressure sensitive and/or comprises a predefined discharging direction. Also preferably the capsule may be arranged in the filter section of the aerosol generating article and/or is in fluidic connection to a further aerosol generating product or core coated with flavoured layer. It is conceivable that at least one flavoured layer and/or the protective layer coated on the core is dissolvable by the inner flavouring liquid comprised in the capsule.

Additionally or alternatively, the inner flavouring liquid of the capsule may interact with the protective layer of an adjacent with flavouring and/or protective layer coated core. In this case, it is conceivable that the non-flavoured protective layer may be enhanced with the third flavouring. Thus, the consumer may enjoy the first flavouring immediately after heating the aerosol generating section and generating the vapor, which preferably dissolves the first layer when the vapour flows along the flowpath. When the first flavouring layer is dissolved, the consumer may activate the capsule for dissolving the protective layer and/or enriching the protective layer with a third flavouring. After dissolving the protective layer, the consumer may enjoy the second flavouring, wherein the second flavoured layer interacts with the vapour.

The objective is also reached by a method for manufacturing an aerosol generating product for use in an aerosol generating article as described above. The aerosol generating product may be arranged in a filter section or cooling section of the aerosol generating article and interacts with a vapor flow which is generated in an aerosol generating section of the article. The generated vapor flows along a flowpath from the heated aerosol generating section to the filter section. The aerosol generating product comprises at least one core which modifies the properties of the vapor. According to the invention, the method is characterized by coating the core or a plurality of cores successively with a first and a second flavoured layers by spraying a first and a second flavours on the core. It is conceivable to coat the flavoured and/or the protective layers onto the core by glazing.

Preferably the core or the plurality of cores are provided by in the tobacco industry common manufacturing steps. Thus, it is conceivable that the core or the plurality of cores are manufactured depending on its structure. In case of the capsule comprising an inner liquid, preferably a flavoured liquid, a crushable shell is preferably provided before the inner liquid is fillable into the shell. It is conceivable that the manufacturing step of the capsule comprises a sealing step.

Alternatively or additionally, the core comprising charcoal may be manufactured in a separated manufacturing step by forming the charcoal to a diameter between 100 and 1000 microns. Also preferably, the method may comprise a mixing step, wherein several materials such as humectants, binder, flavour- barrier material, flavourings or carrier material are mixed to prepare a flavoured and/or protective mixture. Preferably the flavoured and/or protective mixture forms the flavouring and/or protective layer of the aerosol generating product.

It is conceivable that the flavoured and/or protective layers are applied on the core by passing several applying areas of manufacturing machinery sequentially one after another as separate application steps or stages of the coating process. Preferably the manufacturing machinery is divided in at least two different applying areas, for example an applying area for applying the first flavoured layer and another applying area for coating the applying the second flavoured layer on the core. It is conceivable that the manufacturing machinery additionally comprises an applying area for applying the protective layer on the core.

According to another embodiment, the method comprises coating the core or the plurality of cores sequentially with the first flavour to provide the first flavoured layer, a flavour-barrier material to provide a protective layer and the second flavour to provide the second flavoured layer. Preferably, the flavour-barrier material is tasteless, non-flavoured and/or comprises a flavor neutral binder material. The flavour- barrier material might be dissolvable by a moisture comprised in the vapor or an inner liquid comprised in the capsule. According to another embodiment, the method comprises coating the core or the plurality of cores in a rotary cylinder. Preferably the manufacturing machinery comprises the rotary cylinder with several application sections which are separated from each other. Also preferably, each application section coats the core with one flavouring or protective layer. It is conceivable that each flavouring and/or protective layer goes through an air flow process in the rotary cylinder to avoid the cross-contamination in the different application sections.

According to another embodiment, the cylinder is rotated at 4 - 7 RPM and/or coating is applied at a temperature between 40 - 50 °C. Preferably the mixture is applied at a relative humidity of at least 60% in the rotary cylinder to avoid breaking of the flavoured and/or protective layers during the application step.

Preferably the mixture may comprise tobacco powder. Also preferably the core or the plurality of cores comprises dimensions in range of 100 pm and 1000 pm. This particle size allows a proper air flow circulation for the applying step with the rotary cylinder.

As used herein, the term “vapor” may include a suspension of precursor as one or more of: solid particles, liquid droplets, gas, smoke. The suspension may be in the form of an aerosol containing small liquid droplets and gas.

Further advantages, objectives and features of the present invention will be described, by way of example only, in the following description with reference to the appended figures. In the figures, like components in different embodiments can exhibit the same reference symbols.

The figures show:

Fig. 1 schematic cross-sectional lateral view of an aerosol generating article comprising an aerosol generating product in a filter section;

Fig. 1a schematic cross-sectional lateral view of an filter section with two compartments comprising an aerosol generating product;

Fig. 2 schematic cross-sectional lateral view of an aerosol generating product with solid core; Fig. 3 schematic cross-sectional lateral view of an aerosol generating product with liquid core;

Fig. 4 schematic cross-sectional lateral view of an aerosol generating article comprising aerosol generating products in a filter section and a cooling section;

Fig. 5 schematic cross-sectional lateral view of an aerosol generating article comprising an aerosol generating product in an aerosol generating section;

Fig. 6 flow chart of a method for manufacturing an aerosol generating product with two coating steps;

Fig. 7 flow chart of a method for manufacturing an aerosol generating product with three coating steps.

Figure 1 shows a schematic cross-sectional lateral view of an aerosol generating article 2 comprising an aerosol generating product 1 in a filter section 3.

The aerosol generating article may be a “heat-not-burn” aerosol generating article containing tobacco-based aerosol-forming substrate in an aerosol generating section which is heated to a temperature below combustion of the substrate (in particular tobacco) in order to form a vapor. The heating may be implemented in an electrically heating device or, less preferably, by a combustible carbon source positioned adjacent the aerosol generating section. The heating device may comprise a heating chamber configured for receiving at least the aerosol generating section of the aerosol generating article. The heating chamber may be heated by an external heater (e.g., thin film, heating coil, etc.), or a heating blade or pin insertable in the aerosol generating article or be heated by induction such as by a heating susceptor or susceptors inserted in aerosol generating section.

The shown aerosol generating article 2 comprises, when viewed from a mouth end to a tip end, the filter section 3, a cooling section 16 and an aerosol generating section 4. The aerosol generating section 4 preferably comprises substances for generating an inhalable vapour which flows, when the user sucks air at the mouth end, from the aerosol generating section 4 to the filter section 3 of the article 2 along a flow path fp. Thus thereby generated vapour flow vf interacts with the aerosol generating product 1.

The shown aerosol generating product 1 comprises a plurality p of cores 5 which comprise preferably a solid material with a hydrophilic character. Such material might comprise charcoal or a mixture of charcoal with tobacco particles and binder or agglomerated tobacco particles with binder (shown in fig. 2). However, the plurality p of cores 5 are coated with at least two dissolvable flavoured layer which interacts with the vapour flow vf and enhances the vapour with a flavour.

The aerosol generating product 1 is arranged in the filter section 3 of the article 2. The shown filter section 3 comprises a filter compartment 18 comprising a filtering material and a cavity filter compartment 17. The cavity filter compartment 17 is preferably surrounded by the filter compartment 18. It is conceivable, but not necessary, that the cavity filter compartment 17 is entirely filled with the plurality p of coated cores 5. The cavity may be demarcated at both ends of the filter compartment 18 by a filter plug (not shown). Alternatively, the plurality p of coated cores 5 may also be embedded in the filter material (e.g., filter tow) of the filter section without a single cavity being necessarily formed to encase the full aerosol generating product 1 . However, the vapour flow vf passes all sections 4, 16, 3 of the article 2 before it enters a consumers mouth.

Figure 1a shows a schematic cross-sectional lateral view of a filter section 3 with two compartments 17, 18 comprising an aerosol generating product 1. In particular, figure 1a shows another embodiment of the filter section 3 of the article 2 as shown in figure 1. However, preferably the cavity filter compartment 17 is a first compartment of the filter section 3 to be passed by the vapour flow vf. Also preferably, the filter compartment 18 is a second compartment of the filter section 3 to be passed by the vapour flow vf until the vapour enters the mouth of the consumer (not shown).

Preferably, the cavity filter compartment 17 and the filter compartment 18 are sequentially arranged one after another. Preferably the cavity is formed by at least one wrapper 19 which also envelopes the filter compartment 17. The filter section 3 may also be formed of two monoacetate segments, which are spaced apart from each other, and both are enveloped with at least one common wrapper 19 to form a cavity. In the shown embodiment, the filter compartment 18 comprises a first aerosol generating product 1 which comprises a core 5 filled with liquid. Preferably the core 5 is a capsule 5a which is coated with at least one flavoured and/or protective layer 6, 7, 8 (shown in fig.3). Also preferably, the capsule 5a is pressure sensitive and extrudes the liquid 15 (shown in fig. 3) against the flow path fp.

The shown cavity filter compartment 17 comprises a second aerosol generating product 1. Preferably the second aerosol generating product 1 comprises the plurality p of solid cores 5. Also preferably the cores comprise charcoal and/or agglomerated tobacco powder coated with at least one flavoured and/or protective layer 6, 7, 8 (shown in fig.2).

Preferably the first aerosol generating product 1 is dischargeable towards the second aerosol generating product 1. Also preferably the second aerosol generating product comprise cores 5 coated with flavoured and/or protective layer 6, 7, 8 which is dissolvable by the inner flavouring liquid 15 of the first aerosol generating product 1.

Figure 2 shows schematic cross-sectional lateral view of an aerosol generating product 1 with solid core 5. Preferably the core 5 is charcoal which is coated on its surface s1 at least partially. Alternatively, or additionally to charcoal, the core comprises tobacco powder 13, aerosol former and binder material which are evenly distributed throughout the core 5.

The shown core 5 comprises a round shape being circumferentially coated by several flavouring and/or protective layers 6, 7, 8. In particular, the shape of the aerosol generating product 1 resembles a granule with an average size of at least 1000 pm. Preferably the first flavoured layer 6 is applied on the surface s1 of the core 5 covering it entirely. The first flavoured layer 6 is preferably sheathed by the protective layer 8. And finally, the protective layer 8 is coated by the second flavoured layer 7.

Preferably the first flavoured layer 6 comprises a first thickness t1 of at least 50 pm, preferably 100 pm. The thickness t1 of the first flavoured layer 6 may vary depending on at least the coating method used for coating the flavouring onto the core 5. It is conceivable to reach an even thickness t1 , t2, t3 for the flavoured and/or protective layer 6, 7, 8 by spraying. Addi- tinally, the second flavouring layer 8 may comprise a similar or different thickness t2. Preferably the first and second layers 6, 8 are separated by the protective layer 8 which comprises a thickness t3 in range of 30 pm and 70 pm, preferably 70 pm and 120 pm. In the shown embodiment the flavoured and the protective layers 6, 7, 8 comprise the similar thickness t1 , t2, t3. Figure 3 shows a schematic cross-sectional lateral view of an aerosol generating product 1 formed as a single capsule with a liquid core 5. The mentioned aerosol generating product 1 comprises an ellipsoid shape preferably as a conventional capsule for smoking articles. Preferably the core 5 is a capsule 5a comprising a breakable shell 14 and an inner flavouring liquid 15. The flavouring liquid 15 may comprise aerosol former 11 , binder 12, tobacco powder 13 or other additives and flavourings.

The capsule 5a is preferably surrounded by the first and second flavoured layers 6, 7 and the protective layer 8. All layers 6, 7, 8 comprise a thickness t1 , t2, t3 which may vary depending on different conditions. It is conceivable that the flavoured layers 6, 7 comprise a greater thickness t1 , t2 than the thickness t3 of the protective layer 8. This may be advantageous for a rapid resolution of the protective layer 8.

Figure 4 shows a schematic cross-sectional lateral view of an aerosol generating article 2 comprising aerosol generating products 1 in a filter section 3 and a cooling section 16. Preferably the cooling section 16 comprises a tubular element to ensure the stability of the article 2. However, the cooling section 16 may comprises a cavity, for example formed of a hollow paper tube and/or a wrapping 19, in which a first aerosol generating product 1 with the plurality p of coated cores 5, as described in fig. 2, might be arranged. The cooling section 16 is preferably at least partially closed on one side by the aerosol generating section 4 and on the other side by the filter section 3.

The shown aerosol generating article 2 further comprises a second aerosol generating product 1 arranged in the filter section 3. The second aerosol generating product 1 may comprise a coated capsule 5a with at least one flavoured and/or protective layer 6, 8. In particular, the mode of working is similar to the embodiment shown in figure 1a. The difference is that the filter section 3 comprises only one compartment 18 and the first aerosol generating product 1 is comprised in the cooling section 16 of the article 2. However, the first aerosol generating product 1 can be wetted with the liquid 15 comprised in the second aerosol generating product 1.

Preferably first and the second flavoured layers 6, 7 of the first aerosol generating product 1 are dissolvable by a moisture comprised in the vapour flow and generated by heating the aerosol generating section to the aerosolizing temperature of the aerosol formers present in the section. Also preferably the protective layer 8 might be dissolvable by the liquid 15 of the first aerosol generating product 1 .

Figure 5 shows a schematic cross-sectional lateral view of an aerosol generating article 2 comprising an aerosol generating product 1 in an aerosol generating section 4. The aerosol generating section 4 might comprise further materials suitable for generating inhalable vapour. For example, the aerosol generating section 4 comprises reconstituted tobacco and/or tobacco leaf. Preferably, reconstituted tobacco is selected from the list of: cast tobacco, tobacco paper, laminated tobacco, extruded tobacco, tobacco foam and combinations thereof. The reconstituted tobacco can be formed into sheet(s), shreds, strips, fragments. It can be blended with tobacco lamina, expanded tobacco and/or cellulose fibre. Preferably the aerosol generating product 1 enhances the generated vapour with at least one flavour when the flavoured layers 6, 7 of the aerosol generating product 1 dissolve.

Figures 6 and 7 show flow charts of a method for manufacturing 100 an aerosol generating product 1 with two or three coating steps. Preferably a core 5 or the plurality p of cores 5 are provided before the coating steps of the method. As described above, it is conceivable that the core 5 might comprise a solid or a liquid structure. However, this condition might not influence the method 100.

Preferably the method 100 comprises a first coating step 101 , wherein a first flavouring or a first mixture may be applied onto the core 5 to obtain a first flavoured layer 6. Afterwards as a second coating step 102, preferably a second flavouring or a second mixture is applied onto the first flavoured layer 6 to obtain the second flavoured layer 7 (shown in fig. 6). It is conceivable that a drying step is carried out between the first 101 and second 102 step to avoid a cross-contamination of flavours. Alternatively or additionally, the method 100 might comprise a third coating step 103 (shown in fig.7).

Preferably all coating steps 102, 102, 103 are carried out one after another under a relative humidity of at least 60% and an ambient temperature of at least 40 C°. Also preferably, a rotary cylinder is used for applying flavouring and/or protective layers 6, 7, 8 onto the core 5. List of reference symbols

1 aerosol generating product

2 aerosol generating article

3 filter section

4 aerosol generating section

5 core

5a capsule

6 first flavoured layer

7 second flavoured layer

8 protective layer

9 granules

10 charcoal

11 aerosol former

12 binder

13 tobacco powder

14 breakable shell

15 inner flavouring liquid

16 cooling section / cavity section

17 cavity filter compartment

18 filter compartment

19 wrapping p plurality of cores vf vapour flow fp flow path s1 surface of the core t1 thickness of the first layer t2 thickness of the second layer t3 thickness of the third layer

100 method for manufacturing an aerosol generating product

101 first coating step

102 second coating step

103 third coating step

Claims

Surface treatment for tobacco material

Claims

1. An aerosol generating product (1) for use in an aerosol generating article (2), wherein the aerosol generating product (1) is arranged in a filter section (3) of the aerosol generating article (2) for interacting with a vapor flow (vf) which is generatable in an aerosol generating section (4) of the article, wherein the generated vapor flowing along a flowpath (fp) from the heated aerosol generating section (4) to the filter section (3) during use of the aerosol generating article (2), wherein the aerosol generating product (1) comprises at least one core (5) which modifies the properties of the vapor, characterized in that the aerosol generating product (1) further comprises at least a first (6) and a second (7) flavoured layers which are coated onto the common core (5), wherein the first (6) and the second (7) layers are dissolvable by a moisture comprised in the vapor flow (vf) one after another thereby modifying the vapor with a first and a second flavouring, wherein the first (6) and second (7) flavour layers are separated by a protective layer (8) preventing thereby flavour cross-contamination between the flavour layers and wherein the protective layer (8) is non-flavoured.

2. Aerosol generating product (1) according to claim 1, characterized in that the protective layer (8) is a sugar-based or starch layer.

3. Aerosol generating product (1) according to any of the preceding claims, characterized in that each coated layer (6, 7, 8) has a thickness between 10 microns and 1000 microns.

4. Aerosol generating product (1) according to any of the preceding claims, characterized in that a plurality of cores (p) is formed of granules (9) of tobacco substrate and/or charcoal

(10) being arranged in the filter section (3) or in a cavity section (16) or heated aerosol generating section (4).

5. Aerosol generating product (1) according to claim 4, characterized in that the plurality of cores (p) comprises an aerosol former (11), wherein the aerosol former

(11) comprises at least one of the following ingredients: water, monovalent alcohols, polyvalent alcohols, sugar alcohols, sugars and/or polyvalent alcohol esters.

6. Aerosol generating product (1) according to any of the preceding claims, characterized in that the plurality of cores (p) comprises a binder (12) such as gums, starch or cellulose derivatives.

7. Aerosol generating product (1) according to any of the preceding claims, characterized in that the core (5) or each of the plurality of cores (p) has a maximum dimension or diameter between 100 and 1000 microns.

8. Aerosol generating product (1) according to any of the preceding claims, characterized in that the core (5) comprises agglomerated tobacco powder (13) having a median particle diameter (D50) equal to or smaller than 50 microns, preferably equal or smaller than 30 microns.

9. Aerosol generating product (1) according to claims 1 - 6, characterized in that the core (5) is a capsule (5a) comprising a breakable shell (14) and an inner flavouring liquid (15), wherein the liquid (15) modifies the vapor with a third flavouring.

10. A method (100) for manufacturing an aerosol generating product (1) for use in an aerosol generating article (2), wherein the aerosol generating product (1) is arranged in a filter section (3) of the aerosol generating article (2) for interacting with a vapor flow (vf) which is generated in an aerosol generating section (4) of the article (2), wherein - 18- the generated vapor flows along a flowpath (fp) from the heated aerosol generating section (4) to the filter section (3), wherein the aerosol generating product (1) comprises at least one core (5) which modifies the properties of the vapor, characterized by coating (101, 102) the at least one core (5) and optionally one or more further cores (p) successively with a first (6) and a second (7) flavoured layers by spraying a first and a second flavours on the core (5), by coating (101, 102, 103) sequentially the at least one core (5) and optionally one or more further cores (p) with the first flavour to provide the first flavoured layer, a flavour-barrier material to provide a protective layer and the second flavour to provide the second flavoured layer. Method according to claims 10, characterized by coating the core or the plurality of cores in a rotary cylinder. Method according to claim 11, characterized in that the cylinder is rotated at 4 - 7 RPM and / or coating is applied at a temperature between 40 - 50 °C.