EP4362716A1

EP4362716A1 - Flat tobacco article comprising at least two layers and aerosol generating device with such an article

Info

Publication number: EP4362716A1
Application number: EP22735464.4A
Authority: EP
Inventors: Yasuhiro Miyatani
Original assignee: JT International SA
Current assignee: JT International SA
Priority date: 2021-06-30
Filing date: 2022-06-29
Publication date: 2024-05-08
Also published as: JP2024525319A; WO2023275121A1; KR20240027615A; US20240268452A1

Abstract

The present invention concerns a flat-shaped tobacco article defining a pair of parallel outer surfaces, at least one of said outer surfaces being intended to be heated by a flat heater of an aerosol generating device, the flat-shaped tobacco article comprising a substrate layer (81) comprising tobacco substrate and at least one retainer layer (82) in contact with a side of the substrate layer (81) and comprising an agent retainer impregnated with a vapour forming agent, the at least one retainer layer comprising only agent retainer impregnated with vapour forming agent, the agent retainer not comprising any tobacco or nicotine containing substrate, said layers (81, 82) being arranged parallel to said outer surfaces.

Description

FLAT TOBACCO ARTICLE COMPRISING AT LEAST TWO LAYERS AND AEROSOL GENERATING DEVICE WITH

SUCH AN ARTICLE

FIELD OF THE INVENTION

The present invention concerns a flat-shaped tobacco article comprising at least one retainer layer.

The present invention also concerns an aerosol generating assembly comprising such an article and an aerosol generating device configured to operate with this article. The tobacco article comprises for example a solid substrate able to form aerosol when being heated. Thus, the aerosol generating device configured to operate with the article, also known as a heat-not-burn device, is adapted to heat, rather than burn, the substrate by conduction, convection and/or radiation, to generate aerosol for inhalation.

BACKGROUND OF THE INVENTION

The popularity and use of reduced-risk or modified-risk devices (also known as vaporisers) has grown rapidly in the past few years as an aid to assist habitual smokers wishing to quit smoking traditional tobacco products such as cigarettes, cigars, cigarillos, and rolling tobacco. Various devices and systems are available that heat or warm vaporizable substances as opposed to burning tobacco in conventional tobacco products.

A commonly available reduced-risk or modified-risk device is the heated substrate aerosol generation device or heat-not-burn device. Devices of this type generate aerosol or vapour by heating an aerosol substrate comprised in a tobacco article usable with such type of devices. The aerosol substrate typically comprises moist leaf tobacco or other suitable vaporizable material to a temperature typically in the range 150°C to 350°C. Heating an aerosol substrate, but not combusting or burning it, releases aerosol that comprises the components sought by the user but not the toxic and carcinogenic by-products of combustion and burning. Furthermore, the aerosol produced by heating the tobacco or other vaporizable material does not typically comprise the burnt or bitter taste resulting from combustion and burning that can be unpleasant for the user and so the substrate does not therefore require the sugars and other additives that are typically added to such materials to make the smoke and/or vapour more palatable for the user. It is clear therefore that the aerosol generation from the substrate through the whole vaping session presents a challenging issue. For example, in some cases, the aerosol substrate can generate vapour at the beginning of the session and can be exhausted at the end. Thus, the quantity of vapour generated during the session can vary significantly that can cause undesirable user experience.

SUMMARY OF THE INVENTION

The present invention aims to propose a tobacco article for using with a heat-not- burn device which can provide a better user experience during the whole vaping session. Particularly, the invention aims to enhance and make it last during the whole vaping session aerosol generation ensured by a tobacco article when it is used with a heat-not-burn device.

For this purpose, the invention relates to a flat-shaped tobacco article defining a pair of parallel outer surfaces, at least one of said outer surfaces being intended to be heated by a flat heater of an aerosol generating device; the flat-shaped tobacco article comprising:

- a substrate layer comprising tobacco substrate;

- at least one retainer layer in contact with a side of the substrate layer and comprising an agent retainer impregnated with a vapour forming agent; said layers being arranged parallel to said outer surfaces.

Thanks to these features, it is possible to obtain different layers of the tobacco article which have different response times while being heated. Particularly, by “response time”, it should be understood the time that is necessary to the corresponding layer to provide the desired effect when it is being heated. The desired effect can be vapour generation. Different response times imply different temperatures of the corresponding layers at least at some moments of the vaping session. These layers can be used to store separately at least a part of the vapour forming agent from the tobacco substrate. By adapting the properties of these layers, their composition and respective arrangement, it is possible to enhance vapour generation at different moments of the vaping session. For example, it is possible to enhance vapour generation at early stages of the vaping session (i.e. preheating stage) or on the contrary, at the end of the vaping session. Advantageously, the agent retainer does not comprise any tobacco or nicotine containing substrate. In other words, the agent retainer is free of any tobacco or nicotine containing substrate.

According to some embodiments, the agent retainer is chosen in the group consisting of unwoven fabric; cotton and paper.

Thanks to these features, an appropriate agent retainer adapted to retain the vapour forming agent and heat it until a suitable temperature at a suitable moment of the vaping session can be chosen.

According to some embodiments, the vapour forming agent is chosen in the group consisting of:

- polyol such as sorbitol, glycerol;

- glycol such as propylene glycol or triethylene glycol;

- non-polyol such as monohydric alcohols;

- acid such as lactic acid, glycerol derivatives;

- esters such as triacetin, triethylene glycol diacetate, triethyl citrate, glycerine or vegetable glycerine;

- any mixture of the previously cited elements.

Thanks to these features, an appropriate vapour forming agent adapted to release vapour when being heated until a suitable temperature at a suitable moment of the vaping session can be chosen.

According to some embodiments, the retainer layer extends along the whole said side of the substrate layer.

Thanks to these features, it possible to make homogeneous heat transfer between said layers of the tobacco article.

According to some embodiments, the article comprises two retainer layers.

According to some embodiments, the retainer layers are in contact with either side of the substrate layer. According to some embodiments, the retainer layers are arranged to form different distances until the flat heater when the flat-shaped tobacco article is used with the aerosol generating device.

Thanks to these features, it is possible to arrange the retainer layers with different distances until the heater of the aerosol generating device. Thus, these layers can present different response times while being heated by the heater and generate vapour at different moments of the vaping session.

According to some embodiments, the retainer layers have different thicknesses.

Thanks to these features, it is possible to further control heat transfer between the corresponding layers and thus, control response time of each layer to generate vapour at different moments of the vaping session.

According to some embodiments, the retainer layers comprise different vapour forming agents.

According to some embodiments, said different vapour forming agents have a difference in response time while being heated.

According to some embodiments, the retainer layers comprise different agent retainers.

Thanks to these features, it is possible to further control the response time of the retainer layers at different moments of the vaping session.

According to some embodiments, the article comprises a filter part arranged in extension of said layers.

Thanks to these features, the aerosol formed by the substrate layer and the or each retainer layer can be filtered before being delivered to the user.

According to some embodiments, the article comprises a wrapper wrapping said layers together. Thanks to these features, it is possible to attach different layers of the article between them.

The invention also relates to an aerosol generating assembly comprising:

- an aerosol generating device comprising a flat heater;

- a flat-shaped tobacco article intended to be heated by the heater to generate aerosol.

According to some embodiments, the retainer layers comprise between them different vapour forming agents.

According to some embodiments, the vapour forming agent of one of the retainer layers is different from the vapour forming agent of the other retainer layers.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and its advantages will be better understood upon reading the following description, which is given solely by way of non-limiting example and which is made with reference to the appended drawings, in which:

- Figure 1 is a perspective view of an aerosol generating assembly according to the invention, the aerosol generating assembly comprising an aerosol generating device and a flat-shaped tobacco article;

- Figure 2 is a perspective view of the flat-shaped tobacco article of Figure 1 ;

- Figure 3 is a perspective view of a heating chamber of the aerosol generating device of Figure 1 , the heating chamber receiving the flat-shaped tobacco article;

- Figure 4 is a cross-sectional view of a part of Figure 2 according to plane IV, the flat shaped tobacco article being according to a first embodiment of the invention;

- Figure 5 is a cross-sectional view of a part of Figure 2 according to plane V, the flat shaped tobacco article being according to a second embodiment of the invention; and - Figure 6 is a cross-sectional view of a part of Figure 2 according to plane VI, the flat shaped tobacco article being according to a third embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Before describing the invention, it is to be understood that it is not limited to the details of construction set forth in the following description. It will be apparent to those skilled in the art having the benefit of the present disclosure that the invention is capable of other embodiments and of being practiced or being carried out in various ways.

As used herein, the term “aerosol generating device” or “device” may include a vaping device to deliver an aerosol to a user, including an aerosol for vaping, by means of a heater element explained in further detail below. The device may be portable. “Portable” may refer to the device being for use when held by a user. The device may be adapted to generate a variable amount of aerosol, e.g. by activating the heater element for a variable amount of time (as opposed to a metered dose of aerosol), which can be controlled by a trigger. The trigger may be user activated, such as a vaping button and/or inhalation sensor. The inhalation sensor may be sensitive to the strength of inhalation as well as the duration of inhalation to enable a variable amount of vapour to be provided (so as to mimic the effect of smoking a conventional combustible smoking article such as a cigarette, cigar or pipe, etc.). The device may include a temperature regulation control to drive the temperature of the heater and/or the heated aerosol generating substance (aerosol pre-cursor) to a specified target temperature and thereafter to maintain the temperature at the target temperature that enables efficient generation of aerosol.

As used herein, the term “aerosol” may include a suspension of vaporizable material as one or more of: solid particles; liquid droplets; gas. Said suspension may be in a gas including air. Aerosol herein may generally refer to/include a vapour. Aerosol may include one or more components of the vaporizable material.

As used herein, the term “vaporizable material” or “precursor” may refer to a smokable material which may for example comprise nicotine or tobacco and a vapour forming agent. Tobacco may take the form of various materials such as shredded tobacco, granulated tobacco, tobacco leaf and/or reconstituted tobacco. The vaporizable material may also comprise at least one of a gelling agent, a binding agent, a stabilizing agent, and a humectant. As used herein, the term “vapour forming agent” or “aerosol forming agent” or “aerosol former” may referrer to: a polyol such as sorbitol, glycerol, and glycols like propylene glycol or triethylene glycol; a non-polyol such as monohydric alcohols, acids such as lactic acid, glycerol derivatives, esters such as triacetin, triethylene glycol diacetate, triethyl citrate, glycerin or vegetable glycerin. In some embodiments, the aerosol generating agent may be glycerol, propylene glycol, or a mixture of glycerol and propylene glycol. A vapour forming agent may also refer to any mixture of the previously cited elements.

Figure 1 shows an aerosol generating assembly 10 comprising an aerosol generating device 11 and flat-shaped tobacco article 12 inserted into the aerosol generating device 11 . This flat-shaped tobacco article 12 is shown in more detail on Figure 2.

In reference to Figure 2, the flat-shaped tobacco article 12, referenced here-below as tobacco article 12, is for example a flat-shaped cuboid extending along a longitudinal axis X and having external dimensions LxWxD. In a typical example, the length L of the article according to the longitudinal axis X equals substantially to 33 mm while its width W and depth D are substantially equal respectively to 12 mm and 1 ,2 mm. According to different examples, the values L, W and D can be selected within a range of +/- 40%, for example. Flowever, in the general case, the dimensions of the flat-shaped tobacco article 12 of the invention are not limited to specific ranges. The depth D of the tobacco article 12 is formed by a pair of parallel walls 13A, 13B, called hereinafter article lateral walls 13A, 13B, and the width W of the tobacco article 12 is formed by a pair of parallel walls 14A, 14B, called hereinafter article contact walls 14A, 14B. The article walls 13A, 13B, 14A, 14B form two parallel pairs of outer surfaces of the tobacco article 12. According to other examples of the invention, the tobacco article 12 can have any other suitable flat shape and/or external dimensions. In a general case, the flat shape of the tobacco article should be understood as a shape having its depth for example at least 5 times, advantageously at least 10 times and more advantageously at least 15 times less than each of its longitudinal and/or transversal dimension.

The tobacco article 12 comprises a heater part 15 and a mouthpiece part 16 arranged along the longitudinal axis X. In some embodiments, the tobacco article 12 may comprise only the heater part 15. The heater part 15 may for example be slightly longer than the mouthpiece part 16. For example, the length L2 of the heater part 15 according to the longitudinal axis X may be substantially equal to 18 mm and the length L1 of the mouthpiece part 16 according to the longitudinal axis X may be substantially equal to 15 mm. The heater part 15 defines an abutting end 18 of the article 12 and the mouthpiece part 16 defines a mouth end 20 of the article 12. The heater part 15 and the mouthpiece part 16 may be fixed one to the other by a unique wrapper extending around the longitudinal axis X. In other embodiments, the parts 15, 16 may be wrapped by different wrappers and fixed one to the other by any other suitable mean. The or each wrapper may, for example, comprise paper and/or non-woven fabric and/or aluminium. The or each wrapper may be porous or air impermeable. The or each wrapper forms a plurality of airflow channels extending inside the article 12 between the abutting end 18 and the mouth end 20.

The heater part 15 is intended to be heated by a heater (using a heating chamber in the present example) and comprises vaporizable material as defined above. The vaporizable material may be arranged to form two or more different layers. These layers will be explained in more detail referring to cross-sectional views of the heater part 15 shown on Figures 4 to 6, according to different embodiments of the invention.

According to the example of Figure 1 , the mouthpiece part 16 is intended to be received inside a mouthpiece of aerosol generating device 11 . According to other examples of the invention, the mouthpiece part 16 forms itself a mouthpiece intended to be in contact with the user’s mouth and/or lips. The mouthpiece part 16 comprises a core 17 acting for example like a filter. The core 17 may for example be a foam, or packed strands or fibres. The core 17 may be formed through an extrusion and/or rolling process into a stable shape. The article may be shaped to provide one or more airflow channels. In the particular example of Figure 2, the mouthpiece part 16 defines a plurality of venting holes 22 arranged for example according to the whole perimeter of the mouthpiece part 16 along two axis perpendicular to the longitudinal axis X. In other words, according to this example, the venting holes 22 are arranged on each wall of the article among the article lateral walls 13A, 13B and the article contact walls 14A, 14B. According to another example, the venting holes 22 are arranged only on the article contact walls 14A, 14B or preferably, only on one of the article contact walls 14A, 14B. In both examples, the venting holes 22 may be aligned perpendicularly to the longitudinal axis X on the or each corresponding wall of the tobacco article 12, and can be spaced by a same distance. The venting holes 22 allow fresh air entering inside the tobacco article 12 to achieve particular vaping/tasting effects.

Referring again to Figure 1 , the aerosol generating device 11 comprises a device body 30 forming at least one side wall 40. The device body 30 comprises a mouthpiece 32 and a housing 34 arranged successively according to axis Y shown on Figure 1 . According to different examples of the invention, the mouthpiece 32 and the housing 34 can form two different pieces or one single piece. Particularly, in case of two different pieces, the mouthpiece 32 is designed to be fixed on or be received in an insertion opening formed at one of the ends of the housing 34.

In each cross section, the housing 34 may for example form a substantially rectangular shape with rounded edges. In this case, the housing 34 with the mouthpiece 32 form at least four side walls 40. According to other examples, the housing 34 can have a round cross-sectional shape. In this case, it can form with the mouthpiece 32 only one side wall 40. The housing 34 can be formed from a single piece or several assembled pieces made of any suitable material like aluminium or plastic. In some embodiments, the material of the housing 34 can be a thermally conductive material. In some other embodiments, it can be a thermally insulating material. In some embodiments, the housing 34 can form on the corresponding part of the device side wall 40 one or several openings suitable for arranging control and/or visual elements. For example, such element may comprise control buttons, touch panels, screens, LEDs, etc. Particularly, in the example of Figure 1 , the housing 34 forms a slot opening 42 receiving for example a LED indicating at least an ON state of the device 11 . It can also indicate for example a battery law state, an error state, etc.

In some examples, the housing 34 and/or the mouthpiece 32 may form an air inlet 43 in a fluid communication with an airflow path inside the device 11 . This air inlet 43 can be formed for example on the side wall 40, for example in the transition zone between the mouthpiece 32 and the housing 34, as it is shown on Figure 1. According to another example, the air inlet can be formed in a bottom wall of the housing 34, opposite to the insertion opening of the housing 34.

The mouthpiece 32 forms an air outlet 44 in a fluid communication with the airflow path inside the device 11 . Particularly, the air outlet 44 is configured to deliver to the user aerosol formed inside the device 11 . In some examples, the air outlet 44 may also be used to load the tobacco article 12 inside the device 11. In some other examples, the tobacco article 12 can be loaded inside the device 11 when the mouthpiece 32 is detached from the housing 34. The housing 34 delimits an internal space of the device 11 receiving various elements designed to carry out different functionalities of the device 11. This internal space can for example receive a battery for powering the device 11 , a control module for controlling the operation of the device 11 , a heating chamber 45 for heating the tobacco article 12 and at least one heating element 47 for heating the heating chamber 45. Among these elements, only the heating chamber 45 and the heating element 47 will be explained in further detail in reference to Figure 3.

Referring to this Figure 3, the heating chamber 45 forms a cup-shaped heating chamber extending along the axis Y between a proximal end 70 and a distal end 71. The heating chamber 45 is designed to receive the heater part 15 of the tobacco article 12. For this purpose, the heating chamber 45 defines substantially the same cross-sectional shape as the tobacco article 12. Particularly, in the example of the Figure 3, the heating chamber 45 defines a rectangular cross-sectional shape with two parallel chamber lateral walls 73A, 73B and two parallel chamber contact walls 74A, 74B. The heating chamber 45 also defines a distal wall 75 arranged perpendicularly to the axis Y. Particularly, the distal wall 75 is adjacent to each of the walls 73A, 73B, 74A, 74B.

The heating chamber 45 is adapted to receive at least the heater part 15 of the tobacco article 12 so as the longitudinal axis X coincides with the axis Y, the article lateral walls 13A, 13B face the respective chamber lateral walls 73A, 73B and the article contact walls 14A, 14B face the respective camber contact walls 74A, 74B.

According to different examples of the invention, the distal end 71 of the heating chamber 45 may be sealed or may define at least one opening. In the first case, the proximal end 70 of the chamber 45 may form the unique opening of the chamber 45 configured to receive the tobacco article 12 with a play. Particularly, in this case, an airflow channel can be formed between each pair of the lateral walls 13A, 73A and 13B, 73B of the article 12 and the chamber 45, while the corresponding contact walls 14A, 74A and 14B, 74B can be in contact one with the other. As it is shown on Figure 3, while using the device 11 , in this case, an airflow path can extend from the air inlet 43 through the airflow channels formed between the corresponding pairs of lateral walls and then, after a “U”-turn inside the heating chamber 45 through the tobacco article 12 until the air outlet 44. In the second case, all of the walls of the tobacco article 12 can be in contact with the corresponding walls of the heating chamber 45. In this case, while using the device 11 , an airflow path can extend from the air inlet 43 through the opening formed in the distal end 71 and then, through the tobacco article 12 until the air outlet 44. According to other examples, the heating chamber 45 may form other openings for example in its lateral or contact walls to form an airflow path through the tobacco article 12.

As shown on Figure 3, the heating element 47 is arranged in contact with one of the chamber contact walls 74A, 74B outside of the heating chamber 45. Particularly, in the example of this Figure, the heating element 47 is arranged adjacent to an outer surface of the chamber contact wall 74A. The heating element 47 is a flat heater which may comprise a polyimide film heater extending along substantially the total area of said outer surface of the chamber contact wall 74A or only along a part of this surface. The heating element 45 is powered by the battery and controlled by the control module of the aerosol generating device 11 . In some embodiments, the aerosol generating device 11 may comprise two heating elements 47, each heating element 47 being attached on the outer surface of one of the chamber contact walls 74A, 74B.

Figure 4 shows a cross-sectional view of the heater part 15 of the tobacco article 12 according to the first embodiment of the invention. Thus, as it is shown on this Figure 4, the heater part 15 of the tobacco article 12 comprises a substrate layer 81 and a retainer layer 82 arranged parallel to the substrate layer 81 . Both layers may be wrapped together using a unique wrapper. The wrapper may further extend on the abutting end 18 of the article 12 and may form an opening on this end.

The substrate layer 81 comprises tobacco substrate as for example shredded tobacco, granulated tobacco, tobacco leaf and/or reconstituted tobacco. According to some examples, the substrate layer 81 may further comprise a vapour forming agent integrated into the tobacco substrate. The retainer layer 82 comprises an agent retainer impregnated with a vapour forming agent. The agent retainer is chosen for example in the group comprising:

- unwoven fabric;

- cotton; and

- paper.

The agent retainer can be impregnated with the vapour forming agent in a liquid or gas form using any suitable manufacturing process. For example, this can be done while forming the layers 81 , 82 or after the layers have been formed and attached together but before the wrapping. After being impregnated, the agent retainer keeps substantially unchanged its internal structure and stocks the vapour forming agent for example in a form of droplets between different segments of this internal structure.

Advantageously, the retainer layer 82 consists of said agent retainer impregnated with said vapour forming agent. In other words, in this case, the retainer layer 82 comprises only said elements and notably, does not comprise any tobacco or nicotine containing substrate.

Advantageously, in the case where the substrate layer 81 also comprises a vapour forming agent. This vapour forming agent may be chosen different or substantially the same that the vapour forming agent comprised in the retainer layer 82, based on the response time of each layer 81 , 82.

As it is shown on Figure 4, the retainer layer 82 is adjacent to a bottom side of the substrate layer 81 and extends for example according to the whole area of this side. The retainer layer 82 can for example be thicker than the substrate layer 81 .

According to different examples of the invention, at least one of the layers 81 , 82 is intended to be heated directly by the heating element 47. Particularly, as used herein, a layer of the tobacco article 12 is considered to be heated directly by the heating element 47 when there is no any other layer of the tobacco article 12 between this layer and the heating element 47. However, other elements, like the wrapper or the corresponding wall of the heating chamber 45 may be interposed between this layer and the heating element 47. In the example of Figure 4, the retainer layer 82 is for example intended to be heated directly by the heating element 47 and the substrate layer 81 is intended to be heated through the retainer layer 82. In this case, according to the example of Figure 3, the retainer layer 81 should be in contact (eventually via the wrapper) with the chamber contact wall 74A heated directly by the heating element 47. For this purpose, the tobacco article 12 may for example define a unique insertion orientation. This insertion orientation can for example be indicated on the wrapper or be defined by a specific shape of the article 12 and/or the heating chamber 45 preventing the insertion of the tobacco article 12 according to the other orientation. In some examples, the user can chose the orientation of the tobacco article 12 in respect with the heating element 47 according to his/her own preferences.

Figure 5 shows a cross-sectional view of the heater part 15 of the tobacco article 12 according to the second embodiment of the invention. Thus, as it is shown on this Figure, the heater part 15 may comprise the same substrate layer 81 and retainer layer 82 as those explained above. Additionally to these layers 81 , 82, the heater part 15 can further comprise another retainer layer 83. This retainer layer 83 is referred hereinafter as top retainer layer 83 whereas the retainer layer 82 is referred hereinafter as bottom retainer layer 82.

The top retainer layer 83 is arranged parallel to the layers 81 , 82 so as, for example, the substrate layer 81 is arranged between the retainer layers 82, 83. The top retainer layer 83 can form the same thickness as the bottom retainer layer 82 and can have the same composition as this bottom retainer layer 82. Notably, the top retainer layer 83 can include the same vapour forming agent as the bottom retainer layer 82. As in the bottom retainer layer 82, the vapour forming agent of the top retainer layer 83 can be impregnated into the corresponding agent retainer. In this case, difference in the response time of the retainer layers 82, 83 may ensured by different distances until the heating element 47. For example, when the bottom retainer layer 82 is intended to be heated directly by the heating element 47, the top retainer layer 83 is arranged with a greater distance until the heating element 47 and defines thus, a greater response time.

In a variant of the second embodiment of the invention, the retainer layers 82, 83 can include different vapour forming agents and/or agent retainers. For example, the bottom retainer layer 82 may comprise propylene glycol and the top retainer layer may comprise vegetable glycerine. This variant is notably suitable in case of two heating elements 47 attached to opposite chamber contact walls 74A, 74B.

Figure 6 shows the third embodiment of the tobacco article 12. According to this embodiment, the heater part 15 of the tobacco article 12 comprises the same layers 81 , 82, and 83 as those explained in reference with the second embodiment. The only difference of the third embodiment consists in a difference between the thicknesses of the retainer layers 82, 83. For example, as shown on Figure 6, the bottom retainer layer 82 can be thicker than the top retainer layer 83. Additionally, as in the previous case, the retainer layers 82, 83 can comprise the same vapour forming agents and/or agent retainers or different vapour forming agents and/or retainers.

Of course, other embodiments corresponding to any combination of the embodiments cited below are possible. Additionally, for the person skilled in art, it is clear that the number of retainer layers and/or their arrangement and/or their thickness and/or their composition can be adapted basing on the desired response time of each of this layer.

Claims

1. A flat-shaped tobacco article (12) defining a pair of parallel outer surfaces (14A, 14B), at least one of said outer surfaces (14A, 14B) heatable by a flat heater (47) of an aerosol generating device (11); the flat-shaped tobacco article (12) comprising:

- a substrate layer (81) comprising tobacco substrate;

- at least one retainer layer (82, 83) in contact with a side of the substrate layer (81) and comprising an agent retainer impregnated with a vapour forming agent, the at least one retainer layer (82, 83) comprising only agent retainer impregnated with vapour forming agent, the agent retainer not comprising any tobacco or nicotine containing substrate; said layers (81 , 82, 83) being arranged parallel to said outer surfaces.

2. The flat-shaped tobacco article (12) according to claim 1 , wherein the agent retainer is chosen in the group consisting of:

- unwoven fabric;

- cotton;

- paper.

3. The flat-shaped tobacco article (12) according to claim 1 or 2, wherein the vapour forming agent is chosen in the group consisting of:

- polyol such as sorbitol, glycerol;

- glycol such as propylene glycol or triethylene glycol;

- monohydric alcohols;

- acid such as lactic acid, glycerol derivatives;

- any mixture of the previously cited elements.

4. The flat-shaped tobacco article (12) according to any one of the preceding claims, wherein the retainer layer (82, 83) extends along the whole said side of the substrate layer (81).

5. The flat-shaped tobacco article (12) according to any one of the preceding claims, comprising two retainer layers (82, 83).

6. The flat-shaped tobacco article (12) according to claim 5, wherein the retainer layers (82, 83) are in contact with either side of the substrate layer (81).

7. The flat-shaped tobacco article (12) according to any one of claims 5 or 6, wherein the retainer layers (82, 83) have different thicknesses.

8. The flat-shaped tobacco article (12) according to any one of claims 5 to 7, wherein the retainer layers (82, 83) comprise different vapour forming agents.

9. The flat-shaped tobacco article (12) according to claim 8, wherein said different vapour forming agents have a difference in response time while being heated, vapour forming agents requiring different time to provide vapour generation.

10. The flat-shaped tobacco article (12) according to any one of claims 5 to 9, wherein the retainer layers (82, 83) comprise different agent retainers.

11 . The flat-shaped tobacco article (12) according to any one of the preceding claims, further comprising a filter part (16) arranged in extension of said layers.

12. The flat-shaped tobacco article (12) according to any one of the preceding claims, further comprising a wrapper wrapping said layers (81 , 82, 83) together.

13. An aerosol generating assembly (10) comprising:

- an aerosol generating device (11) comprising a flat heater (47);

- a flat-shaped tobacco article (12) intended to be heated by the flat heater (47) to generate aerosol, the flat-shaped tobacco article (12) being according to any one of the preceding claims.

14. An aerosol generating assembly (10) according to claim 13, wherein the retainer layers (82, 83) are arranged to form different distances until the flat heater (47).