Aerosol generating article for an HNB aerosol generating device

Abstract

The present invention concerns an aerosol generating article for an HNB aerosol generating device, the aerosol generating article extending along an article axis (X) and comprising: - a substrate portion (12); - a filter portion (14) defining a mouth end; - a filter wrapper wrapping at least the filter portion (14); wherein the filter wrapper forms a plurality of airflow channels (140) extending at least partially along the article axis (X), the airflow channels being distributed according to a circumferential direction (Y) around the filter portion (14).

Description

[0001] Aerosol generating article for an HNB aerosol generating device

[0002] FIELD OF THE INVENTION

[0003] The present invention concerns an aerosol generating article.

[0004] Particularly, the aerosol generating article according to the invention is configured to operate with an aerosol generating device, also known as a heat-not-burn device or HNB device. Such type of aerosol generating devices is adapted to heat, rather than burn, a substrate portion comprised in the article.

[0005] BACKGROUND OF THE INVENTION

[0006] 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.

[0007] Available reduced-risk or modified-risk devices are so called “aerosol generating devices” or “heat-not-burn devices” which are configured to heat vaporizable materials as opposed to burning tobacco in conventional tobacco products.

[0008] Such an aerosol generating device is configured to generate aerosol or vapour by heating an aerosol generating substrate that is usually comprised in a consumable article separate from the aerosol generating device.

[0009] The aerosol generating substrate contains for example blends of moist tobacco leaf, reconstituted tobacco substrate or other suitable vaporizable material that vaporizes at a temperature typically in the range of 150°C to 350°C. According to some known examples, the aerosol generating substrate comprises propylene glycol (PG) and / or vegetable glycerin (VG).

[0010] Heating an aerosol generating substrate, without combusting or burning it, releases aerosol that comprises the components sought by the user but not by-products of combustion and burning. Furthermore, the aerosol produced by heating the vaporizable material contained in the aerosol generating substrate does not comprise the typical burnt or bitter taste resulting from combustion and burning that can be unpleasant for the user and the smoke that can be irritating and polluting for the surroundings.

[0011] One prominent issue with HNB devices is the high temperature experienced primarily at the beginning of the session. This is due to hot water vapour being produced first, as it has a lower boiling point than PG and VG. Additionally, the filter region of the aerosol generating article having a high specific heat capacity, generally absorbs the heat produced during the initial heating and transfers it to the wrapper e.g. a tipping paper, in the filter region. In this way, the outer surface of the wrapper in contact with the user’s lips becomes too hot. This means the user can feel a high temperature on the lips, which is an unpleasant experience in the session.

[0012] SUMMARY OF THE INVENTION

[0013] One of the aims of the present invention is to propose an aerosol generating article for an HBN device which can improve the user experience by avoiding high temperature in the mouth end region in contact with the user’s body, notably with the user’s lips.

[0014] For this purpose, the invention relates to an aerosol generating article for an HNB aerosol generating device, the aerosol generating article extending along an article axis and comprising:

[0015] - a substrate portion;

[0016] - a filter portion defining a mouth end;

[0017] - a filter wrapper wrapping at least the filter portion; wherein the filter wrapper forms a plurality of airflow channels extending at least partially along the article axis, the airflow channels being distributed according to a circumferential direction around the filter portion.

[0018] The airflow channels formed on the filter wrapper provide thus air pockets between the outer surface of the aerosol generating article and the user’s lips. These air pockets decrease the temperature felt by the user in contact with the filter wrapper. As air has a low thermal conductivity, even a thin air pocket of 0.2 mm height would create a useful cooling effect. Additionally, circumferential distribution of the airflow channels around the filter portion makes the cooling effect irrespective of the orientation of the aerosol generating article in the mouth of the user. Depending on different embodiments explained in more detail below, the circumferential distribution as well as the cross-sectional shape and area of the airflow channels may be homogeneous. In this case, the cooling effect is substantially constant according to any orientation of the aerosol generating device in the mouth of the user. According to other embodiments, the circumferential distribution and / or the cross- sectional shape or area of the airflow channels may be inhomogeneous. In this case, the cooling effect may be adjusted depending on the orientation of the aerosol generating article in the user’s mouth.

[0019] The number of airflow channels can be greater than 5 and preferably is comprised between 10 and 20.

[0020] It was observed that this number of channels can ensure the desired cooling effect while remaining technically feasible in manufacturing.

[0021] The depth of each airflow channel can be comprised between 0.05 mm and 0.5 mm, advantageously between 0.1 mm and 0.4 mm and more advantageously between 0.2 mm and 0.35 mm.

[0022] In some embodiments, the airflow channels may cover at least 30%, advantageously 40% and more advantageously 50% of the total surface area of the filter wrapper. For the example, the total external surface area of the filter wrapper can be comprised between 400 mm2and 600 mm2whereas the area covered by the airflow channels can be comprised between 200 mm2and 300 mm2.

[0023] In some embodiments, the airflow channels may cover between 50% and 80% of the total surface area of the filter wrapper.

[0024] According to some embodiments, the or each airflow channel is formed by embossing and / or debossing at least a part of the filter wrapper.

[0025] The embossing and / or debossing can be performed using one or a pair of rollers configured to apply a predetermined pattern to on one or both surfaces of the filter wrapper. When the filter wrapper presents at least two layers, the embossing and / or debossing can be applied on at least one layer of the filter wrapper. The predetermined pattern can be constant along the rotation axis of the rollers. Alternatively, the predetermined pattern can vary according to this axis. In this case, it is possible to form airflow channels having different shapes and / or dimensions according to the article axis. Both embossed and debossed airflow channels perform similarly on the final product. However, during manufacturing, debossing can be preferred according to some embodiments. This is due to the rollers designed to hold the uniformly curved surface of the aerosol generating articles with a set diameter. Therefore, any debossed features are less prone to flattening by the rollers.

[0026] As used herein, the term “embossing and / or debossing” refers to the case when either only embossing or only debossing or both embossing and debossing is(are) applied. It some case, the term “bossing” is used instead.

[0027] According to some embodiments, the filter wrapper can be embossed and / or debossed in order to increase the cross-sectional area of the airflow channels formed in the filter portion.

[0028] According to some embodiments, the airflow channels are arranged uniformly according to the circumferential direction and form substantially a same cross-sectional area according to the circumferential direction.

[0029] Thanks to these features, it is possible to achieve a same cooling effect according to any orientation of the aerosol generating article in the user’s mouth.

[0030] According to some embodiments, the airflow channels are arranged non-uniformly according to the circumferential direction and / or form different cross-sectional areas according to this direction.

[0031] In this case, the achieved cooling effect depends on the orientation of the aerosol generating article in the user’s mouth. Particularly, a greater cooling effect can be achieved in regions having a greater concentration of the airflow channels, since the contact surface with the user’s lips is decreased. A lower cooling effect may be achieved in regions where the channels have a greater cross-sectional area, since the contact surface with the user’s lips is increased. Thus, the user can control the cooling effect simply by changing the orientation of the aerosol generating article in his / her mouth.

[0032] In some embodiments, the airflow channels form a same or unchanged cross- sectional area along the article axis. In this case, a constant pattern along the article axis can be used to form the channels. Thus, it is possible to form these channels in a simple way using for example an embossing and / or debossing process as previously disclosed. Additionally, it was observed that the airflow guided by an airflow channel having a same cross-sectional area is sufficient to ensure the desired cooling effect.

[0033] In some embodiments, the airflow channels form a decreasing cross-sectional area along the article axis in the direction towards the mouth end.

[0034] Provided with these features, the airflow guided by the airflow channels can be accelerated in the direction towards the mouth end. This contributes to diminishing of the temperature in the region of contact with the user’s lips. Additionally, a lower cross-section area of the airflow channels in the region of contact with the user’s lips decreases the contact surface of the lips with the filter portion. Therefore, a better cooling effect can be achieved.

[0035] In some embodiments, each airflow channel presents a rectilinear shape extending along the article axis.

[0036] Thus, the airflow channels can be formed in a simple way, using for example an embossing and / or debossing process or any other available process.

[0037] In some embodiments, each airflow channel presents a helical shape extending around the article axis.

[0038] The helical shape of the airflow channels can be formed by forming channels having a wave shape when the filter wrapper is unrolled. The ends of each wave can match each other so as to form a looped channel when the filter wrapper is rolled around the filter portion. The helical shape of the airflow channels allows controlling of the cooling effect depending on the orientation of the aerosol generating article in the user’s mouth.

[0039] In some embodiments, the airflow channels are formed on the outer surface of an outer wrapper of the filter wrapper. In some embodiments, the airflow channel are formed on the outer surface of the aerosol generating article, the outer surface of the aerosol generating article being intended to be in contact with the user’s lip.

[0040] Here, the outer surface of the aerosol generating article onto which the airflow channel are formed is the outer surface of an outermost wrapper of the filter wrapper, for example the outer surface of an outermost sleeve of the filter wrapper.

[0041] For example, the outermost sleeve is made up of silicon. Silicon provides a pleasant feeling on the lips of the user and presents a relatively low thermal conductivity, in particular in comparison with other materials typically used for such sleeves.

[0042] In some embodiments, at least one airflow channel is formed inside the filter wrapper, advantageously between different layers forming the filter wrapper. In particular, each airflow channel extends from at least one hole formed in an outer layer to the mouth end.

[0043] The outer wrapper can be formed by a tipping paper which assembles the filter portion with the substrate portion. Before being rolled around the filter portion, the tipping paper can be embossed and / or debossed to form airflow channels on the outer surface of the tipping paper.

[0044] Alternatively, the outer wrapper can be embossed and / or debossed after being rolled around the filter portion. In this case, the same embossing and / or debossing may be provided to the inner wrapper being placed adjacent to the outer wrapper during embossing and / or debossing.

[0045] Alternatively, the outer wrapper can comprise a separate sleeve made with debossed and / or embossed features. The sleeve can be applied over the filter portion and a tipping paper to form the airflow channels as explained above. The sleeve can be made of silicon.

[0046] Alternatively, bossed features made for example of silicon can be glued to the filter portion and then wrapped to give the bossed appearance and form the airflow channels. Additional benefits of silicon include its good feeling on the lips for the user and its lower thermal conductivity. Silicon also allows debossed features without the problem of potential crushing by the rollers.

[0047] When a sleeve or bossed features are used, the rest of the aerosol generating article can be manufactured in a conventional way and then, the sleeve or bossed features can be applied.

[0048] In some embodiments, the filter wrapper presents a multilayer structure comprising at least two layers.

[0049] In this case, the filter wrapper can comprise an outer wrapper and an inner wrapper. The inner wrapper can for example be formed by a plug wrap. The outer wrapper can for example be formed by a tipping paper, sleeve or bossed features, as explained above.

[0050] The filter wrapper can also form a multilayer structure comprising at least three layers.

[0051] According to some embodiments, the airflow channels are formed between different layers of the multilayer structure.

[0052] Particularly, the airflow channels can be formed between the inner and the outer wrappers. Alternatively, the airflow channels can be formed between a pair of layers of the outer wrapper or a pair of layers of the inner wrapper.

[0053] The airflow channels can be formed between a pair of layers by providing these layers with bossed features delimiting the airflow channels. The bossed features can be formed by an embossing and / or debossing process as previously explained.

[0054] The airflow channels formed between a pair of layers are invisible by the user. Thus, the aerosol generating article can preserve its conventional appearance while ensuring the desired cooling effect at the mouth end.

[0055] It was observed that in the aerosol generating articles having airflow channels formed between a pair of layers, the draw resistance can be controlled in the same way as for the conventional products. In some examples,, this draw resistance can be controlled by adapting the number and the dimensions of the holes forming inlets for these channels.

[0056] BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The invention and its advantages will be better understood upon reading the following description, which is given by way of none-limiting examples and which is made with reference to the appended drawings, in which:

[0058] - Figure 1 is a schematic view of an aerosol generating article according to the invention;

[0059] - Figures 2 to 7 are schematic detailed views of different embodiments of a filter wrapper of the aerosol generating article according to Figure 1 ; and

[0060] - Figure 8 is a result of a numeric simulation showing temperature of different regions of the aerosol generating article according to Figure 1 during a vaping session.

[0061] DETAILED DESCRIPTION OF THE INVENTION

[0062] 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.

[0063] The expression “substantially equal to” is understood hereinafter as an equality at plus or minus 10% and preferably at plus or minus 5%.

[0064] As used herein, the term “aerosol generating device” or “device” may include a vaping device to deliver aerosol from a tobacco article received in the device, for example comprising tobacco. 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 a heating system for a variable amount of time (as opposed to a metered dose of aerosol) using 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 vapor to be provided (so as to mimic the effect of smoking a conventional combustible smoking article such as a cigarette, cigar or pipe, etc.).

[0065] As used herein, the term “aerosol generating substrate” or “aerosol substrate” or “tobacco substrate” may refer to a material that is designed to deliver aerosol upon heating in an aerosol generating device and which may for example comprise nicotine or tobacco and an aerosol former. Tobacco may take the form of various materials such as shredded tobacco, tobacco cut filler, granulated tobacco, tobacco leaf and / or reconstituted tobacco. Reconstituted tobacco can be produced in the form of a sheet by any suitable process such as paper making process, cast sheet, extrusion / lamination. The sheet can then be gathered, cut or shredded, optionally mixed with cellulose or other fillers, tobacco lamina, stems, aerosol former, additives, flavour (e.g., menthol), acid (e.g., benzoic acid), and wrapped in a wrapper to form a tobacco portion. The filling density of the tobacco portion is not particularly limited, but is usually 250 mg I cm3 to 900 mg I cm3 from the viewpoint of ensuring the performance of the tobacco portion and imparting a good taste. Suitable aerosol formers include: 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, 1 ,3-butanediol, glycerin or vegetable glycerin. Suitable amount of aerosol former may be between e.g., 5 wt. % and 50 wt.% of the substrate. In some embodiments, the aerosol generating agent may be glycerol, propylene glycol, or a mixture of glycerol and propylene glycol. The substrate may also comprise at least one of a gelling agent, a binding agent, a stabilizing agent, and a humectant.

[0066] As used herein, the term “aerosol” may include a suspension of precursor as one or more of: solid particles; liquid droplets; gas. Said suspension may be in a gas including air. Aerosol may be formed by the aerosol generating substrate and may comprise one or several components of it. The aerosol is generally obtained by a temperature increase of the aerosol generating substrate, such as at a temperature less than 400°C, preferably up to 350°C.

[0067] As used herein, the term “vaping session” may refer to a using period of the aerosol generated device starting from the activation of the trigger defined above to the moment in which the aerosol generation device is disabled. As used herein, the terms “upstream” and “downstream” refer to a position relative to the direction of the flow in the article towards the mouth end.

[0068] As used herein, the term “longitudinal” refers to the extension direction of the article axis. The term “length” refers to a dimension measured according to the article axis.

[0069] GENERAL DESCRIPTION

[0070] In reference to Figure 1 , the aerosol generating article 10 extends according to an article axis X between a mouth end and substrate end. According to the example of this Figure, the aerosol generating article 10 comprises a substrate portion 12 forming the substrate end, a filter portion 14 forming the mouth end and a filter wrapper 16. The aerosol generating article 10 is designed to be used with an aerosol generating device, such an HNB device where the substrate portion 12 is heated and not burnt. For this purpose, the substrate portion 12 is for example configured to be received in a heating chamber of the aerosol generating device where it is heated using any suitable technique known as such. The aerosol generating article 10 has for example a cylindrical shape with a circular or oval cross-section.

[0071] As it is shown in Figure 1 , the substrate portion 12 and the filter portion 14 are arranged successively according to the article axis X.

[0072] In a preferred example, the length of the substrate portion 12 is comprised between 10 and 30 mm, preferably between 15 and 25 mm, more preferably substantially equal to 20 mm (+ / - 2 mm). In said example, the length of the filter portion 14 is comprised between 10 and 30 mm, preferably between 15 and 25 mm, more preferably substantially equal to 20 mm (+ / - 2 mm).

[0073] The substrate portion 12 contains an aerosol generating substrate as defined above. The substrate portion 12 is wrapped in a substrate wrapper (not shown) which is advantageously rolled around the whole length of the substrate portion 12 and keeps the ends of the substrate portion unwrapped. This substrate wrapper is for example formed by a known cigarette paper. In some examples, the substrate wrapper comprises aluminum, e.g. a paper-aluminum laminate. The filter portion 14 contains any material or a combination of materials forming a filter of an airflow generated during heating the substrate portion 12. The filter portion 14 may thus comprise cellulose acetate fiber and / or paper. The filter portion 14 may be formed of a densified bundle of filaments, in particular of cellulose acetate tow, or be a gathered paper sheet or nonwoven. The filter portion may comprise additives such as a plasticizer, for example triacetin. In some examples, the filter portion 14 may further comprise a flavouring element, like a flavouring capsule breakable by the user and / or soluble by heating and / or interaction with saliva.

[0074] The substrate portion 12 and the filter portion 14 are maintained together with the filter wrapper 16. The filter wrapper 16 is composed of at least two elements: an outer wrapper 21 and an inner wrapper 22. Particularly, the inner wrapper 22 is rolled around the filter portion 14 and the outer wrapper 21 is rolled around the inner wrapper 22 and around a part of the substrate portion 12.

[0075] The inner wrapper 22 is for example a plug wrap designed to wrap the filter portion 14 and extends for example according to the whole length of the filter portion 14. The inner wrapper 22 defines thus a downstream part adjacent to the mouth end and an upstream part opposite to the downstream part and adjacent to the substrate portion 12. The inner wrapper 22 is formed for example from a single sheet rolled around the filter portion 14. The inner wrapper 22 overlaps at a small longitudinal sealed seam.

[0076] The outer wrapper 21 is designed to fix the filter portion 14 with the inner wrapper 22 to the substrate portion 12. For this purpose, the outer wrapper 21 has an overlapping zone with each of the inner wrapper 22 and the substrate wrapper. In other words, the length of the outer wrapper 21 may be greater than the length of the inner wrapper 21 to form the overlapping zone with the substrate wrapper. Depending on different examples explained in more detail below, the outer wrapper 21 can present a monolayer structure or a multilayer structure. The outer wrapper 21 can be formed by a tipping paper known as such.

[0077] According to some examples, the filter wrapper 16 is formed only by one wrapper which is the outer wrapper 21 as explained above.

[0078] According to some other examples, the outer wrapper 21 extends according to the whole length of the aerosol generating article 10 (i.e. it covers entirely the substrate portion 12). In the last case, the substrate portion 12 can be provided without the substrate wrapper as mentioned before.

[0079] According to further examples, the inner wrapper 22 can be formed by at least one plug wrap as a conventional cigarette. In this case, the outer wrapper 21 can present a tipping paper and an outer separate sleeve made for example of silicon and designed to form bossed features as it is explained in further detail below. The sleeve can be adapted to be fixed on the filter portion 14. Alternatively, the outer wrapper 21 can be formed by embossed and / or debossed features made for example of silicon and glued on the outer surface of the tipping paper.

[0080] According to the invention, the filter wrapper 16 forms a plurality of airflow channels extending at least partially along the article axis X. In other words, the airflow channels extend along at least a part of the filter portion 14 comprising the mouth end. These airflow channels will be explained below in further detail in reference to different embodiments of the invention.

[0081] FIRST EMBODIMENT

[0082] Figures 2 and 3 shows airflow channels 140 according to a first embodiment.

[0083] As it can be seen in these Figures, the airflow channels 140 present rectilinear channels extending according to the article axis X along the whole length of the filter portion 14. Additionally, the airflow channels 140 can be distributed, advantageously evenly, around the filter portion 14 according to the circumferential direction Y.

[0084] The airflow channels 140 can be formed on the outer wrapper 21 using a predetermined constant pattern all along the article axis X. In this case, the airflow channels 140 present a constant shape and constant dimensions along the article axis X. Advantageously, the number and / or dimensions of the airflow channels 140 are adapted so as the airflow channels 140 cover at least 50% of the area of the outer wrapper 21 .

[0085] The outer wrapper 21 can present a monolayer structure formed for example from paper, advantageously from tipping paper. Additionally, as it is shown in part B of Figures 2 and 3 illustrating the outer wrapper in an unrolled state, the predetermined pattern can be applied on the whole width and length of the outer wrapper 22. Thus, when the outer wrapper is rolled around the filter portion 14, the airflow channels 140 can be distributed all around the filter portion 14.

[0086] As it is shown in part C of Figures 2 and 3, the predetermined pattern can present a continuous wave forming a plurality of valley and ridge regions. In this case, the airflow channels 140 are formed by the valley regions. The wave can be smooth (i.e. present a differentiable function) or form an angle at the top of each ridge region and at the bottom of each valley region (i.e. form a zigzag pattern). In this last case, the angles can be formed by folds extending along the article axis X. Additionally, the angles can present an even degree of change in each step of the full circumference. In other words, each following angle according to the circumferential direction Y can be increased or decreased by a same value in comparison with the previous angle.

[0087] The wave forming the predetermined pattern may present a constant amplitude and a constant wavelength. The amplitude defines the depth of the airflow channels 140. This depth can be comprised between 0.05 mm and 0.5 mm, advantageously between 0.1 mm and 0.4 mm and more advantageously between 0.2 mm and 0.35 mm. The wavelength defines the density (or frequency) of the airflow channels 140 on the surface of the filter wrapper 16. According to some examples, the density of the airflow channels 140 may be linked to their depth. For example, in some embodiments, for a greater density, a lower depth can be used. Inversely, for a greater depth, a lower density can be used. For example, the depth of the airflow channels 140 in Figure 2 may be substantially equal to 0.3 mm ± 0.15 mm. In the example of Figure 3, the density of the airflow channels 140 is greater in comparison with the example of Figure 2. In this Figure 3, the depth of the airflow channels 140 may be substantially equal to 0.15 mm ±0.075 mm.

[0088] Alternatively, the wave may present a variable amplitude and / or a variable wavelength. In case of a variable amplitude, it may vary within the ranges given above.

[0089] When the outer wrapper 21 is separated from the substrate wrapper, the valley regions forming the airflow channels 140 can be flush in respect with the external surface of the substrate wrapper and the ridge regions can form a smooth transition with this surface or at least slightly protrude in respect with this surface. Alternatively, the valley regions forming the airflow channels 140 can form a smooth transition with the surface of the substrate wrapper and the ridge regions can protrude in respect with this surface. To form the airflow channels 140 according to the predetermined pattern, an embossing and / or debossing process can be used. For example, before being rolled around the filter portion 14, the outer wrapper 21 is processed by at least one embossing roller applying the predetermined pattern on one surface of the outer wrapper 21. Advantageously, a pair of rollers can be used. In this case, the predetermined pattern can be simultaneously applied on the opposite surfaces of the outer wrapper 21.

[0090] SECOND EMBODIMENT

[0091] Figure 4 shows airflow channels 240 according to a second embodiment. These airflow channels 240 are similar to the airflow channels 140 according to the first embodiment, except the features disclosed below.

[0092] Particularly, according to the second embodiment, the pattern used to form the airflow channels 240 varies along the article axis X. In this case, the shape and / or dimensions of the airflow channels vary along the article axis X.

[0093] As it shown in Figure 4, the airflow channels 240 form a decreasing cross-sectional area along the article axis X in the direction towards the mouth end 241. In reference to part C of Figure 4 showing the pattern close to the mouth end 241 , each airflow channel 240 has a base portion 242 corresponding to a bottom wall delimiting this channel 240. This base portion 242 becomes wider in the direction towards the substrate portion 12. In other words, the width of the airflow channels 240 increases in the direction towards the substrate portion 12. Advantageously, the depth of the airflow channels 240 remains substantially the same all along the article axis X. Alternatively, the depth of the airflow channels 240 varies along the article axis X. It can for example at least slightly decrease in the direction from the mouth end 241 toward the substrate portion 12.

[0094] As in the previous embodiment, the airflow channels 240 can also be formed using an embossing and / or debossing process. According to this embodiment, a variable pattern is applied by one or two rollers to form the airflow channels 20 with variable shape and / or dimensions according to the article axis X. THIRD EMBODIMENT

[0095] Figure 5 shows airflow channels 340 according to a third embodiment. These airflow channels 340 are similar to the airflow channels 140, 240 according to the previous embodiments, except the features disclosed below.

[0096] Particularly, according to the third embodiment, the pattern used to form the airflow channels 340 varies along the article axis X to form a helical shape of the airflow channels 340 extending around the article axis X. The number of the airflow channels 340 can be greater than or equal to 2. The airflow channels 340 can form a constant shape and / or dimensions at each cross-section.

[0097] The airflow channels 340 can extend parallel to each other. In the example of Figure 5, two airflow channels 340 extend parallel to each other. Alternatively, at least one airflow channel 340 can cross another airflow channel 340 forming for example an angle substantially equal to 90°.

[0098] To form the helical shape of the airflow channels 340, these channels 340 can be first formed on the unrolled outer wrapper 21 in a shape of a wave, as it is shown in part B of Figure 5. This wave can have one central ridge region and two lateral valley regions extending on either side of the central ridge region. The central ridge region can be arranged closer to the border of the outer wrapper 21 designed to form the mouth end, than the lateral valley regions. Additionally, the lateral valley regions may be arranged so as to match each other when the outer wrapper 21 is rolled around the filter portion 14. In this way, each airflow channel 340 can be looped. In some embodiments, several ridge regions and more than two valley regions can be provided.

[0099] Due to the helical shape, the airflow channels 340 are not evenly distributed according to the circumferential direction Y. Thus, the airflow channels 340 according to this embodiment provide different levels of ventilation depending on the orientation of the aerosol generating article 10 in respect with the user’s lips. Particularly, when the aerosol generating article 10 is oriented so as a region with a greater concentration of the airflow channels 340 is in contact with the user’s lips, a greater ventilation level is can be ensured.

[0100] The airflow channels 340 can be formed using an embossing and / or debossing process as previously explained. FOURTH EMBODIMENT

[0101] Figure 6 shows airflow channels 440 according to a fourth embodiment. These airflow channels 440 are similar to the airflow channels 140, 240, 340 according to the previous embodiments, except the features disclosed below.

[0102] Particularly, according to this embodiment, at least one airflow channel 440 is formed inside the filter wrapper 16, advantageously between different layers forming the filter wrapper 16. This channel 440 can have a rectilinear or any other suitable shape and extend from at least one hole 25 and to the mouth end 441. The or each hole 25 can be formed in the outer layer of the filter wrapper 16 (par example in the outer wrapper 21).

[0103] According to a first example of this embodiment (shown in Figure 6), at least one airflow channel 440 is formed between the inner wrapper 22 and the outer wrapper 21. In this case, the outer wrapper 21 can present either a monolayer or a multilayer structure. The airflow channel 440 can for example be formed by embossing and / or debossing an inner surface of the outer wrapper 21 and / or an outer surface of the inner wrapper 22.

[0104] According to a second example of this embodiment (not-shown), the outer wrapper 21 presents a multilayer structure and at least one airflow channel 440 is formed between a pair of layers forming the outer wrapper 21 . Like in the previous case, the airflow channel 440 can be formed by embossing and / or debossing the facing surfaces of these layers.

[0105] Additionally, in some examples, when the outer wrapper 21 presents a multilayer structure, at least one of these layers (for example the outmost layer) can be peelable. For this purpose, as it is shown in Figure 7, a longitudinal tearing line 452 and a circumferential tearing line 453 can be provided. A peelable layer can also be formed in the outer wrapper 21 according to any one of preceding embodiments.

[0106] Additionally, in some examples, the outer wrapper 21 may form on its outer surface embossed and / or debossed features 460 to minimize the contact of the user’s lips with this surface. These features 460 can for example be formed using any suitable pattern. SIMULATION RESULTS

[0107] Figure 8 shows a CFD (computational fluid dynamics) simulation of an airflow inside and near the aerosol generating article 10. In this simulation, M designates a region inside the user’s mouth and L designates a region in contact with the user’s lips.

[0108] During a vaping session, the main part F1 of the airflow (more 90% or even more 95% of the total flow) passes through the filter portion 14. The remaining part F2 (less than 10% or even less than 5% of the total flow) passes through the airflow channels formed by the filter wrapper 16 (airflow channel 140 according to the example of the Figure). As it can be seen on the simulation, the flow F2 significantly cools down the region L, even with a low ratio of the airflow passing through the airflow channels.

Claims

CLAIMS1. An aerosol generating article (10) for an HNB aerosol generating device, the aerosol generating article extending along an article axis (X) and comprising:- a substrate portion (12);- a filter portion (14) defining a mouth end;- a filter wrapper (16) wrapping at least the filter portion (14); wherein the filter wrapper (16) forms a plurality of airflow channels (140; 240; 340; 440) extending at least partially along the article axis (X), the airflow channels being distributed according to a circumferential direction (Y) around the filter portion (14).

2. The aerosol generating article (10) according to claim 1 , wherein the or each airflow channel (140; 240; 340; 440) is formed by embossing and / or debossing at least a part of the filter wrapper (16).

3. The aerosol generating article (10) according to any one of the preceding claims, wherein the airflow channels (140; 240; 440) are arranged uniformly according to the circumferential direction (Y) and form substantially a same cross-sectional area according to the circumferential direction (Y).

4. The aerosol generating article (10) according to any one of claims 1 to 2, wherein the airflow channels (340) are arranged non-uniformly according to the circumferential direction (Y) and / or form different cross-sectional areas according to this direction.

5. The aerosol generating article (10) according to any one of the preceding claims, wherein the airflow channels (140; 340; 440) form a same cross-sectional area along the article axis (X).

6. The aerosol generating article (10) according to any one of claims 1 to 4, wherein the airflow channels (240) form a decreasing cross-sectional area along the article axis (X) in the direction towards the mouth end (241).

7. The aerosol generating article (10) according to any one of the preceding claims, wherein each airflow channel (140; 240; 440) presents a rectilinear shape extending along the article axis.

8. The aerosol generating article (10) according to any one of claims 1 to 6, wherein each airflow channel (340) presents a helical shape extending around the article axis (X).

9. The aerosol generating article (10) according to any one of the preceding claims, wherein the airflow channels (140; 240; 340) are formed on the outer surface of an outer wrapper (21) of the filter wrapper (16).

10. The aerosol generating article (10) according to any one of the preceding claims, wherein the airflow channels (140; 240; 340) are formed on the outer surface of the aerosol generating article (10), the outer surface of the aerosol generating article (10) being intended to be in contact with the user’s lip.

11. The aerosol generating article (10) according to any one of claims 1 to 9, wherein the filter wrapper (16) presents a multilayer structure comprising at least two layers, advantageously at least three layers.

12. The aerosol generating article (10) according to claim 11 , wherein the airflow channels (440) are formed between different layers of the multilayer structure.

13. The aerosol generating article (10) according to claim 11 or 12, wherein at least one outer layer of the multilayer structure is peelable.

14. The aerosol generating article (10) according to any one of claims 11 to 13, wherein the outer wrapper (21) forms on its outer surface embossed and / or debossed features (460) to minimize the contact of the user’s lips with this surface.

15. The aerosol generating article (10) according to any one of the preceding claims, wherein each airflow channel (440) extends from at least one hole (25) formed in an outer layer to the mouth end (441).

16. The aerosol generating article (10) according to any one of the preceding claims, wherein the filter wrapper (16) comprises a sleeve forming at least partially the airflow channels.

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