Aerosol-generating article with chambered mouthpiece

Abstract

An aerosol-generating article comprises a planar aerosol-forming substrate and a mouthpiece. The mouthpiece comprises a proximal portion for insertion into a user's mouth and a distal portion configured for engagement with the aerosol-forming substrate. An airflow path is defined by an airflow channel passing through the mouthpiece between the distal portion and the proximal portion. The airflow channel comprises a first constriction portion and a first expansion portion downstream of the first constriction portion to facilitate mixing and aerosol formation.

Description

[0001] AEROSOL-GENERATING ARTICLE WITH CHAMBERED MOUTHPIECE

[0002] The present disclosure relates to an aerosol-generating article comprising an aerosolforming substrate and a mouthpiece.

[0003] A typical aerosol-generating article may appear similar to a conventional cigarette. For example, such an aerosol-generating article may be a substantially cylindrical article comprising an aerosol-forming substrate and other components such as a mouthpiece filter element, all wrapped in a cigarette paper. Dimensions of typical aerosol-generating articles are often similar to the dimensions of conventional cigarettes.

[0004] Research has shown that, in such a typical aerosol-generating article comprising a plug of aerosol-forming substrate, a significant portion of the plug of aerosol-forming substrate may not be sufficiently heated to form an aerosol during use. This is undesirable since this portion of the plug of aerosol-forming substrate contributes to the cost of manufacture and transport of the aerosol-generating article, but does not contribute to the aerosol delivered to an end user. This may be the case regardless of the way in which the aerosol-forming substrate is heated, for example regardless of whether a resistive or inductive heater is used and regardless of whether the plug of aerosol-forming substrate is heated from the inside or the outside.

[0005] It is an aim of the present disclosure to provide an aerosol-generating article, in which a greater portion of an aerosol-forming substrate of the aerosol-generating article is sufficiently heated to form an aerosol during use.

[0006] According to the present disclosure, there may be provided an aerosol-generating article comprising an aerosol-forming substrate for producing an aerosol. The aerosol-generating article is preferably a substantially planar aerosol-generating article. For example, the aerosolgenerating article may have a base defined by a length extending in an x direction, a width extending in a y direction, and a height extending in a z direction. Preferably, the aerosolgenerating article comprises a mouthpiece. The mouthpiece may be removably couplable to the aerosol-forming substrate. The mouthpiece may be integral with the aerosol-forming substrate. Preferably, an airflow path is defined through the aerosol-forming substrate and the mouthpiece.

[0007] According to the present disclosure, there may be provided an aerosol-generating article comprising an aerosol-forming substrate for producing an aerosol coupled to a mouthpiece. The aerosol-generating article may comprise a substantially planar upper surface defined by a length extending in an x direction and a width extending in a y direction, and a substantially planar lower surface defined by a length extending in an x direction and a width extending in a y direction. The substantially planar upper surface and the substantially planar lower surface may be vertically spaced from each other by a height defined in a z direction.

[0008] According to the present disclosure, there may be provided an aerosol-generating article comprising an aerosol-forming substrate and a mouthpiece. The mouthpiece comprises a proximal portion for insertion into a user’s mouth and a distal portion. The mouthpiece may be engaged with the aerosol-forming substrate. The mouthpiece may be configured for engagement with the aerosol-forming substrate. An airflow path is defined by an airflow channel passing through the mouthpiece between the distal portion and the proximal portion. The airflow channel comprises a first constriction portion and a first expansion portion downstream of the first constriction portion.

[0009] In use, air may be drawn through the aerosol-generating article by a user sucking on the mouthpiece. Air is drawn into and through the aerosol-forming substrate, into the mouthpiece through the first constriction portion and the first expansion portion, and into a user’s mouth. In use, the airflow entrains volatile components of the aerosol-forming substrate that are liberated from the substrate, for example by heating. On passing through the constriction portion and into the expansion portion, the airflow may undergo a Venturi effect in which the pressure of the airflow drops and its speed increases while passing through the constriction, and its pressure increases and its speed decreases on passing into the expansion portion. Turbulence in the airflow is created in the expansion portion. The turbulence facilitates mixing of air and entrained volatile components of the aerosol forming substrate, to homogenise the mixture. The expansion portion also slows the air flow and allows cooling of the airflow and subsequent formation of aerosol.

[0010] The airflow channel may taper or funnel inwards towards the first constriction portion. The airflow channel may taper or funnel outwards away from the first constriction portion, towards the first expansion portion.

[0011] Advantageously, the airflow path may further comprise a second constriction portion downstream of the first expansion portion. The airflow channel may taper or funnel inwards towards the second constriction portion. The airflow channel may taper or funnel outwards away from the second constriction portion. The airflow path may further comprise a second expansion portion downstream of the second constriction portion.

[0012] By providing alternate constriction and expansion of the airflow path, homogenisation and cooling of the airflow path may be improved and a highly homogenised and optimally cooled aerosol may be generated.

[0013] An airflow outlet may be defined at the second expansion portion. An aerosol collection chamber may be defined by the mouthpiece, the aerosol collection chamber being located downstream of the aerosol-forming substrate and upstream of the first constriction portion. The aerosol collection chamber may be a space in which volatile components of the aerosol-forming substrate that are entrained in the airflow can condense to form an aerosol.

[0014] According to the present disclosure, there may be provided an aerosol-generating article comprising an aerosol-forming substrate and a mouthpiece, the mouthpiece comprising a proximal portion for insertion into a user’s mouth. The aerosol-forming substrate has a length dimension that is greater than or equal to a width dimension, and a width dimension that is greater than a thickness dimension. The proximal portion of the mouthpiece may have a major axis dimension which is greater than the width dimension of the aerosol-forming substrate.

[0015] The proximal portion of the mouthpiece may have a transverse cross-section which has a greater area than a transverse cross-section of the aerosol-forming substrate, the transverse cross-section of the substrate and the mouthpiece being cross-sections taken perpendicular to the length dimension of aerosol-forming substrate.

[0016] The mouthpiece may have a distal portion comprising a recess dimensioned for engagement with the aerosol-forming substrate. An airflow path may be defined through the mouthpiece between the distal portion and the proximal portion.

[0017] Non-rod-shaped aerosol-generating articles, particularly predominantly thin planar and flat consumables, have an overall shape that may not be comfortable for a user to draw directly on. A planar aerosol-forming substrate provides benefits in rapid heating response and optimised substrate utilisation, but the shape is not ergonomic due to a very thin profile incorporating sharp edges. Advantageously, a mouthpiece may be combined with a planar aerosol-forming substrate to provide an aerosol-generating article having a comfortable shape for a user to draw on, while still retaining benefits of a planar substrate. The mouthpiece may allow the use of very small substrates, for example very narrow substrates and / or very thin substrates that would be difficult to handle otherwise.

[0018] The mouthpiece may comprise a recess having a shape substantially the same as the transverse cross-section of the aerosol-forming substrate, the transverse cross-section being the cross-section taken perpendicular to the length dimension of the aerosol-forming substrate. The recess may be dimensioned to form a mechanical interaction with the aerosol-forming substrate to couple the aerosol-forming substrate to the mouthpiece. The recess may define a ridge or lip for engaging with the aerosol-forming substrate. The recess may be dimensioned to provide an interference fit with the aerosol-forming substrate.

[0019] The mouthpiece may form an integral part of the aerosol-generating article. That is, the mouthpiece may be an irremovable part of the article. Advantageously, however, the mouthpiece may be removably couplable to the aerosol-forming substrate. Thus, a single mouthpiece may be used to consume many individual aerosol-forming substrates. Thus, the mouthpiece may be a detachable mouthpiece and may be separated from the aerosol-forming substrate.

[0020] The proximal portion of the mouthpiece may be shaped to have an ergonomic fit in a user’s mouth. For example, the proximal portion of the mouthpiece may have a curved transverse cross- sectional shape, for example a curved non-circular cross-sectional shape. The transverse cross- sectional shape may be described as oval or elliptical or lenticular.

[0021] The proximal portion of the mouthpiece may have a cross-sectional shape defined by a maximum width and a maximum height. For example, the maximum width may be between 6 mm and 26 mm, for example between 11 mm and 25 mm, for example between 13 mm and 23 mm, for example about 10 mm, or about 13 mm, or about 16 mm, or about 23 mm. The maximum height may be between 4 mm and 15 mm, for example between 5 mm and 13 mm, for example between 6 mm and 9 mm, for example about 5 mm, or about 5 mm, or about 9 mm, or about 13 mm.

[0022] A transverse cross-section of the proximal portion of the mouthpiece may have a shape defined by a maximum width and a maximum height, in which the ratio of maximum width to maximum height is between 2:1 and 5:1 , for example between 2.5:1 and 4:1 , for example between 3:1 and 3.5:1. A transverse cross-section of the mouthpiece, for example a proximal portion of the mouthpiece, may have an oval, elliptical, or lenticular shape, and a transverse cross-section of the aerosol-forming substrate may have a rectangular cross-section.

[0023] A transverse cross-section of the mouthpiece, for example a proximal portion of the mouthpiece, may have a curved non-circular shape defined by a major axis and a minor axis. A ratio of the maximum dimension of the major axis to the maximum dimension of the minor axis may be between 1.5:1 and 5.5:1 , for example between 2:1 and 5:1 , for example between 2.5:1 and 4: 1 , for example between 3: 1 and 3.5: 1.

[0024] Preferably, the mouthpiece has a length of between 10 mm and 25 mm, for example between 12 mm and 21 mm. An airflow path preferably defined through the length dimension of the mouthpiece and may include one or more chambers and / or airflow constrictions.

[0025] Aerosol-generating articles according to the present disclosure may comprise a mouthpiece portion and a substrate portion, for example a substantially planar substrate portion. Thus, the aerosol-generating articles may be described as flat articles or planar articles.

[0026] Aerosol-generating articles according to the present disclosure may preferably be substantially flat articles or substantially planar articles. Such articles have a large base area relative to the volume of the article, at least with reference to the aerosol-forming substrate portion of the article. Advantageously, a larger base area may provide greater surface area for heating by a planar heater of an aerosol-generating device. Advantageously, a smaller height may allow a smaller temperature gradient or difference across the height of the aerosol-generating article during heating. For example, where the base of the aerosol-generating article is in contact with, and heated by, a planar heater, there may be a smaller temperature difference between the base and an upper surface opposing the base if the spacing, or height, between the base and the upper surface is smaller. Advantageously, this may allow heating of a greater proportion of the aerosolforming substrate of the aerosol-generating article to a temperature at which an aerosol is released, whilst minimising the risk of burning the hottest portion of the substrate closest to the heater. Alternatively, or in addition, this may reduce a time required to heat the aerosol-forming substrate sufficiently to release an aerosol.

[0027] The aerosol-generating article according to any of the aspects disclosed herein may have an air flow path extending through the aerosol-generating article. The aerosol-generating article may have an air-flow path defined through the aerosol-generating article in an x / y plane from one side of the aerosol-generating article to the other side of the aerosol-generating article. The aerosol-generating article preferably has a resistance to draw (RTD) of less than 20 millimetre H2O, for example less than 10 millimetre H2O, in the direction of the airflow path. Preferably, the aerosol-generating article has a RTD of less than 20 millimetre H2O, for example less than 10 millimetre H2O, in at least one direction in an x / y plane of the aerosol-generating article. An aerosol-generating article with a low resistance air-flow path may allow for superior air-flow management and allow aerosol to be extracted more efficiently from the aerosol-generating article and guided to a user. A free flow of air through the substrate may result in a lack of mixing of the airflow and entrained volatile components. Lack of mixing may result in an inhomogeneous aerosol. The use of a mouthpiece as described herein may be of particular benefit in an aerosolgenerating article in which the substrate is a planar substrate, in particular a planar substrate with a free airflow path and a low RTD. The benefits of use of a planar substrate may be obtained while still achieving a homogeneous aerosol.

[0028] Unless otherwise specified, the resistance to draw (RTD) is measured in accordance with ISO 6565-2015. The RTD refers to the pressure required to force air through the full length of a component, such as the aerosol-generating article. The terms “pressure drop” or “draw resistance” of a component or article may also refer to the “resistance to draw”. Such terms generally refer to the measurements made in accordance with ISO 6565-2015 and are normally carried out at under test at a volumetric flow rate of about 17.5 millilitres per second at the output or downstream end of the measured component at a temperature of about 22 degrees Celsius, a pressure of about 101 kPa (about 760 Torr) and a relative humidity of about 60%.

[0029] The aerosol-generating article according to any of the aspects disclosed herein may comprise substantially planar upper and lower surfaces. A vertical separation between the substantially planar upper and lower surfaces may define a height (for example, a z dimension) of the aerosol-generating article. An air flow channel may be defined between the substantially planar upper and lower surfaces. The height of the aerosol-generating article may be less than 5 millimetres, for example between 1.5 millimetres and 5 millimetres, for example between 1.5 millimetres and 4 millimetres, for example between 1.5 millimetres and 3 millimetres, for example between 1.5 millimetres and 2 millimetres. One or both of the substantially planar upper and lower surfaces may comprise an aerosol-forming substrate. The aerosol-generating article may comprise upper and lower layers, at least one of the upper and lower layers comprising or consisting of aerosol-forming substrate, the upper layer forming the substantially planar upper surface and the lower layer forming the substantially planar lower surface.

[0030] According to the present disclosure, there may be provided an aerosol-generating article comprising a substrate portion having a first planar layer, a second planar layer, and a corrugated layer arranged between the first planar layer and the second planar layer, and a mouthpiece coupled to the substrate portion. At least one of the first planar layer, the second planar layer and the corrugated layer may comprise or consist of an aerosol-forming substrate.

[0031] The use of a corrugated structure in the aerosol-generating article may advantageously allow the production of an aerosol-generating article that has extremely low RTD while still being sufficiently rigid to for a user to handle. Further, use of a corrugated structure may allow a low density, low RTD, aerosol-generating article to be produced using high speed production methods similar to those used for production of corrugated cardboard.

[0032] According to the present disclosure, there may be provided an aerosol-generating article, the aerosol-generating article comprising: a substrate portion having a first planar external surface, a second planar external surface, a cavity, a frame positioned between the first planar external surface and the second planar external surface, the frame at least partially defining the cavity, an aerosol-forming substrate positioned between the first planar external surface and the second planar external surface, and an air inlet and an air outlet, an airflow passage extending between the air inlet and the air outlet through the cavity, and a mouthpiece coupled to the substrate portion.

[0033] The frame may comprise a peripheral wall at least partially circumscribing or encircling the cavity. The frame may comprise a peripheral wall wholly circumscribing or encircling the cavity.

[0034] The aerosol-generating article may comprise a first planar external layer and a second planar external layer, in which the first planar external layer forms the first planar external surface and the second planar external layer forms the second planar external surface. Optionally, at least one of the first planar external layer, the second planar external layer, and the frame may comprise or consist of aerosol-forming substrate.

[0035] The cavity may be substantially empty.

[0036] Aerosol-forming substrate may be positioned within the cavity.

[0037] A corrugated layer may be positioned within the cavity.

[0038] The aerosol-generating article of any of the aspects of the present disclosure may have a length (for example, an x dimension) of between 10 millimetres and 100 millimetres, or between 10 millimetres and 50 millimetres, for example between 12 millimetres and 30 millimetres, for example between 14 millimetres and 26 millimetres, for example between 16 millimetres and 24 millimetres, for example between 18 millimetres and 22 millimetres, for example about 18 millimetres, or about 19 millimetres, or about 20 millimetres, or about 21 millimetres, or about 22 millimetres.

[0039] The aerosol-generating article may have a width (for example, a y dimension) of between 5 millimetres and 20 millimetres, for example between 8 millimetres and 18 millimetres, for example between 10 millimetres and 16 millimetres, for example between 11 millimetres and 15 millimetres, for example between 12 millimetres and 14 millimetres, for example about 13 millimetres. The aerosol-generating article may have a height (for example, a z dimension) of between 1 millimetres and 10 millimetres, for example between 1.2 millimetres and 8 millimetres, for example between 1.4 millimetres and 7 millimetres, for example between 1.6 millimetres and 6 millimetres, for example between 1.7 millimetres and 5 millimetres, for example about 1 .7 millimetres, or about 4.5 millimetres, or about 2 millimetres, or about 3 millimetres, or about 4 millimetres.

[0040] At least the substrate portion of an aerosol-generating article of any of the aspects of the present disclosure, when viewed in plan, may have a shape defining a polygon, a quadrilateral (for example, a rectangle or a square), oval, or circle, or a combination thereof. Where the aerosolgenerating article comprises substantially planar upper and lower surfaces, one or both of the upper and lower surfaces when viewed in plan may have a shape defining a polygon, a quadrilateral (for example, a rectangle or a square), an oval, a circle, or a combination thereof. A perimeter of the aerosol-generating article when viewed in plan may be formed of a plurality of straight sides, a plurality of curved sides, or a combination of straight and curved sides. Where the aerosol-generating article comprises substantially planar upper and lower surfaces, a perimeter of one or both of the upper and lower surfaces when viewed in plan may have a shape defining a polygon, a quadrilateral (for example, a rectangle or a square), an oval, a circle, or a combination thereof.

[0041] The aerosol-generating article may consist entirely of aerosol-forming substrate, in which case any mouthpiece may be integrally formed as part of the aerosol-forming substrate. Alternatively, the aerosol-forming substrate may be one of a plurality of component parts of the aerosol-generating article and may be removably couplable to a mouthpiece. The substrate may be described as being detachable from the mouthpiece.

[0042] The aerosol-forming substrate may comprise nicotine. Nicotine may be present in the form of a tobacco material or may be in the form of a nicotine extract.

[0043] Preferably, the aerosol-forming substrate comprises, or consists of, homogenised tobacco material, for example a reconstituted tobacco material or a cast leaf tobacco material.

[0044] The aerosol-forming substrate may comprise, or consist of, a solid aerosol-forming material. The aerosol-forming substrate may comprise a liquid aerosol-forming material, for example a liquid aerosol-forming material retained within a porous matrix. The aerosol-forming substrate may comprise a gel aerosol-forming material.

[0045] The aerosol-forming substrate may comprise one or more aerosol-formers. Suitable aerosol-formers are well known in the art and include, but are not limited to, one or more aerosolformers selected from: polyhydric alcohols, such as propylene glycol, polyethylene glycol, triethylene glycol, 1 , 3-butanediol and glycerine; esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate. It may be particularly preferable for the aerosolformer to be or comprise glycerine.

[0046] The aerosol-forming substrate may comprise aerosol-forming material having at least 1 , 2, 5, 10, or 15 weight percent aerosol-former. The aerosol-forming material may comprise greater than 15 weight percent aerosol-former, for example greater than 20 weight percent, or greater than 25 weight percent, or greater than 30 weight percent, or greater than 40 weight percent, or greater than 50 weight percent aerosol-former.

[0047] The aerosol-forming material may comprise less than or equal to 30 percent by weight of aerosol former, less than or equal to 25 percent by weight of aerosol former, or less than or equal to 20 percent by weight of aerosol former. That is, the aerosol-forming material may have an aerosol former content of less than or equal to 30 percent by weight, less than or equal to 25 percent by weight, or less than or equal to 20 percent by weight.

[0048] The aerosol-forming material may comprise between 1 percent and 30 percent by weight of aerosol former, between 1 percent and 25 percent by weight of aerosol former, or between 1 percent and 20 percent by weight of aerosol former.

[0049] The aerosol-forming material may comprise between 5 percent and 30 percent by weight of aerosol former, between 5 percent and 25 percent by weight of aerosol former, or between 5 percent and 20 percent by weight of aerosol former.

[0050] The aerosol-forming material may comprise between 10 percent and 30 percent by weight of aerosol former, between 10 percent and 25 percent by weight of aerosol former, or between 10 percent and 20 percent by weight of aerosol former.

[0051] The aerosol-forming material may comprise between 15 percent and 30 percent by weight of aerosol former, between 15 percent and 25 percent by weight of aerosol former, or between 15 percent and 20 percent by weight of aerosol former.

[0052] The aerosol-forming material may comprise at least 50 percent by weight of aerosol former, at least 60 percent by weight of aerosol former, or at least 70 percent by weight of aerosol former.

[0053] The aerosol-forming material may comprise less than or equal to 85 percent by weight of aerosol former, less than or equal to 80 percent by weight of aerosol former, or less than or equal to 75 percent by weight of aerosol former.

[0054] The aerosol-forming material may comprise between 50 percent and 85 percent by weight of aerosol former, between 50 percent and 80 percent by weight of aerosol former, or between 50 percent and 75 percent by weight of aerosol former.

[0055] The aerosol-forming material may comprise between 60 percent and 85 percent by weight of aerosol former, between 60 percent and 80 percent by weight of aerosol former, or between 60 percent and 75 percent by weight of aerosol former. The aerosol-forming material may comprise between 70 percent and 85 percent by weight of aerosol former, between 70 percent and 80 percent by weight of aerosol former, or between 70 percent and 75 percent by weight of aerosol former.

[0056] The aerosol-forming material may comprise nicotine. The aerosol-forming material may comprise natural nicotine, or synthetic nicotine, or a combination of natural nicotine and synthetic nicotine.

[0057] The aerosol-forming material may comprise at least 0.5 percent by weight of nicotine, at least 1 percent by weight of nicotine, at least 1 .5 percent by weight of nicotine, or at least 2 percent by weight of nicotine. That is, the aerosol-forming material may have a nicotine content of at least 0.5 percent by weight, at least 1 percent by weight, at least 1 .5 percent by weight, or at least 2 percent by weight.

[0058] The aerosol-forming material may comprise one or more cannabinoid compounds such as one or more of: tetrahydrocannabinol (THC), tetrahydrocannabinolic acid (THCA), cannabidiol (CBD), cannabidiolic acid (CBDA), cannabinol (CBN), cannabigerol (CBG), cannabigerol monomethyl ether (CBGM), cannabivarin (CBV), cannabidivarin (CBDV), tetrahydrocannabivarin (THCV), cannabichromene (CBC), cannabicyclol (CBL), cannabichromevarin (CBCV), cannabigerovarin (CBGV), cannabielsoin (CBE), cannabicitran (CBT). It may be preferable that the cannabinoid compound is CBD or THC. It may be particularly preferable that the cannabinoid compound is CBD.

[0059] The aerosol-forming substrate may comprise one or more flavourants. The one or more flavourants may comprise one or more of: one or more essential oils such as eugenol, peppermint oil and spearmint oil; one or both of menthol and eugenol; one or both of anethole and linalool; and a herbaceous material. Suitable herbaceous material includes herb leaf or other herbaceous material from herbaceous plants including, but not limited to, mints, such as peppermint and spearmint, lemon balm, basil, cinnamon, lemon basil, chive, coriander, lavender, sage, tea, thyme, and caraway. The one or more flavourants may comprise a tobacco material.

[0060] The aerosol-forming material may have a moisture content of about 5 to 25%, preferably of about 7 to 15%, at final product state. For example, the aerosol-forming material may be a homogenised tobacco material with a moisture of about 5 to 25%, preferably of about 7 to 15%, at final product state.

[0061] The aerosol-forming material may comprise tobacco leaf; for example about 15 to 45%, preferably of about 20 to 35% of a blend of tobacco leaf, incorporating at least one of the following tobacco types: bright tobacco; dark tobacco; aromatic tobacco. Tobacco material such as tobacco leaf is preferably ground and graded to a particle size of about 100 to 380 mesh, preferably of about 170 to 320 mesh. “Tobacco type” means one of the different varieties of tobacco, for example based on the distinct curing process that the tobacco undergoes before it is further processed in a tobacco product.

[0062] Examples of bright tobaccos are Flue-Cured Brazil, Indian Flue-Cured, Chinese Flue- Cured, US Flue-Cured such as Virginia tobacco, and Flue-Cured from Tanzania.

[0063] Examples of aromatic tobaccos are Oriental Turkey, Greek Oriental, semi-oriental tobacco but also Fire Cured, US Burley, such as Perique, and Rustica.

[0064] Examples of dark tobacco are Dark Cured Brazil Galpao, Burley Malawi or other African Burley, Sun Cured or Air Cured Indonesian Kasturi.

[0065] The aerosol-forming material may comprise Cellulose fibres. For example, the aerosolforming material may comprise about 1 to 15% of cellulose fibres, preferably of about 3 to 7% of cellulose fibres. Preferably, cellulose fibres may have a length of about 10 to 250 pm, preferably of about 10 to 120 pm.

[0066] The aerosol-forming material may comprise organic fibres such as non-tobacco fibres, or tobacco fibres. For example, the aerosol-forming material may comprise about 5 to 20%, preferably about 7 to 15% of tobacco fibres. Tobacco fibres are preferably derived from stems and / or stalks, graded to fibres of a length of about 10 to 350 pm, preferably of about 10 to 180 pm. The aerosol-forming material may comprise about 10 to 30 %, preferably of about 15 to 25%, of a non-tobacco organic fibre. For example, organic fibres may derive from cellulose, cotton, wood, tea botanical varieties as sub-products, and sub-processed waste, the tea industry. Organic fibres are preferably of a length of about 10 to 400 pm, preferably of about 10 to 200 pm.

[0067] The aerosol-forming material may comprise a binder. For example, the aerosol-forming material may comprise about 1 to 10%, preferably of about 1 to 5%, of a binder such as any of common gums or pectins used in food and beverage (F&B) industries. Preferred binders may be natural pectins, such as fruit, for example citrus, or tobacco pectins; guar gums, land locust bean gums, such as hydroxyethyl and / or hydroxypropyl of those; starches, such as modified or derivatized starches; alginate; methyl, ethyl, ethylhydroxymethyl and carboxy methyl, celluloses; dextran; and xanthan gum. A preferable binder is guar.

[0068] The aerosol-forming material may comprise an organic botanical glycerite. For example, the aerosol-forming material may comprise about 15 to 55 %, preferably of about 20 to 35 %, of botanicals such as Clove, Echinacea sp., Fennel, Ginger, Hawthorn berry, Elderberry, Monarda, Mullein leaves, Nettle, Plantain, Turmeric, Yarrow, and compounds of those.

[0069] The aerosol-forming material may comprise organic botanical extracts. For example, the aerosol-forming substrate may comprise about 1 to 15 %, preferably of about 2 to 7 %, of any of the previously referred botanicals, as well as menthol (dl-Menthol, C10H20G, 2-lsopropyl-5- methylcyclohexanol) such as obtained from Chaerophyllum macrospermum, Mesosphaerum sidifolium, or other related botanic varieties, as well as P-menthan-3-ol, as any secondary alcohol as diastereoisomers of 5-methyl-2-(propan-2-yl)cyclohexan-1-ol.

[0070] The aerosol-forming material may comprise botanical essential oils, for example about 0.5 to 5 %, preferably of about 1 to 3 %, of a botanical essential oil, for example a botanical essential oil such as of palm, coconut, and wooden-based essential oils.

[0071] The aerosol-forming material preferably comprises an aerosol-former, for example about 5 to 35%, preferably of about 10 to 25%, of an aerosol former. Suitable aerosol-formers known in the art include: glycerine; monohydric alcohols like menthol, polyhydric alcohols, such as triethylene glycol; esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyls of those.

[0072] As used herein, the term “aerosol-generating article” may refer to an article able to generate, or release, an aerosol. The article may comprise an aerosol-forming substrate portion and a mouthpiece.

[0073] As used herein, the term “aerosol-forming substrate” may refer to a component part of an aerosol-generating article comprising a material capable of releasing an aerosol or volatile compounds that can form an aerosol. Such volatile compounds may be released from the aerosolforming material by heating the aerosol-forming substrate. An aerosol-forming substrate may substantially comprise, or entirely consist of, an aerosol-forming material. An aerosol-forming substrate may comprise aerosol-forming material and non-aerosol forming material. The non aerosol forming material may provide structure to the aerosol-forming substrate. An aerosolforming material may be adsorbed, coated, impregnated, or otherwise loaded onto a carrier or support to form the aerosol-forming substrate.

[0074] As used herein, the term “aerosol-generating device” may refer to a device for use with an aerosol-generating article to enable the generation, or release, of an aerosol.

[0075] As used herein, the term “aerosol generating system” refers to a combination of an aerosolgenerating device and one or more aerosol-forming articles for use with the device. An aerosolgenerating system may include additional components, such as a charging unit for recharging an on-board electric power supply in an electrically operated or electric aerosol-generating device.

[0076] As used herein, the term “aerosol former” may refer to any suitable known compound or mixture of compounds that, in use, facilitates formation of an aerosol. The aerosol may be a dense and stable aerosol. The aerosol may be substantially resistant to thermal degradation at the operating temperature of the aerosol-forming substrate or aerosol-generating article.

[0077] As used herein with reference to the invention, the term “nicotine”, is used to describe nicotine, nicotine base or a nicotine salt.

[0078] As used herein with reference to the invention, the terms “proximal”, “distal”, “upstream” and “downstream” are used to describe the relative positions of components, or portions of components, of the aerosol-generating article. “Upstream” and “downstream” refer to the direction of airflow when a user draws on an aerosol-generating article or device.

[0079] As used herein, the term “longitudinal” refers to the direction corresponding to the main longitudinal axis of the aerosol-generating article, which extends between the upstream and downstream ends of the aerosol-generating article. During use, air may be drawn through the aerosol-generating article in the longitudinal direction.

[0080] As used herein, the term “sheet” denotes a laminar element having a width and length substantially greater than the thickness thereof. The width of a sheet may be greater than 10 mm, preferably greater than 20 mm or 30 mm. In certain embodiments, sheets of material for use in forming aerosol-forming substrates as described herein may have a thickness of between 10 pm and about 1000 pm, for example between 10 pm and about 300 pm.

[0081] As used herein, the term “homogenised tobacco material” encompasses any tobacco material formed by the agglomeration of particles of tobacco material. Sheets or webs of homogenised tobacco material are formed by agglomerating particulate tobacco obtained by grinding or otherwise powdering of one or both of tobacco leaf lamina and tobacco leaf stems. In addition, homogenised tobacco material may comprise a minor quantity of one or more of tobacco dust, tobacco fines, and other particulate tobacco by-products formed during the treating, handling and shipping of tobacco. The sheets of homogenised tobacco material may be produced by casting, extrusion, paper making processes or other any other suitable processes known in the art.

[0082] The term “cast leaf” is used herein to refer to a product made by a casting process that is based on casting a slurry comprising plant particles (for example, clove particles or tobacco particles and clove particles in a mixture) and a binder (for example, guar gum) onto a supportive surface, such as a belt conveyor, drying the slurry and removing the dried sheet from the supportive surface. An example of the casting or cast leaf process is described in, for example, US-A-5,724,998 for making cast leaf tobacco. In a cast leaf process, particulate plant materials are produced by pulverizing, grinding, or comminuting parts of the plant. The particles produced from one or more plants are mixed with a liquid component, typically water, to form a slurry. Other components in the slurry may include fibres, a binder and an aerosol former. The particulate plant materials may be agglomerated in the presence of the binder. The slurry is cast onto a supportive surface and dried into a sheet of homogenized plant material. Preferably, homogenized plant material used in articles according to the present invention may be produced by casting. Such homogenized plant material may comprise agglomerated particulate plant material.

[0083] As used herein, resistance to draw is expressed with the units of pressure “mm H2O” or “mm WG” or “mm of water gauge” and may be measured in accordance with ISO 6565:2002. The invention is defined in the claims. However, below there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0084] Exi. An aerosol-generating article comprising a substantially planar aerosol-forming substrate coupled to a mouthpiece.

[0085] Exii. An aerosol-generating article comprising a substantially planar aerosol-forming substrate removably-couplable to a mouthpiece, or detachable from a mouthpiece.

[0086] Exiii. An aerosol-generating article comprising a substantially planar aerosol-forming substrate coupled to a mouthpiece, an airflow path being defined through the aerosol-forming substrate and the mouthpiece.

[0087] Exiv. An aerosol-generating article comprising a substantially planar aerosol-forming substrate coupled to a mouthpiece, an airflow path being defined through the aerosol-forming substrate and the mouthpiece, in which the airflow path through the mouthpiece passes through a channel having a first constriction portion and a first expansion portion downstream of the first constriction portion.

[0088] Exv. An aerosol-generating article, for example an aerosol-generating article according to any preceding example, comprising an aerosol-forming substrate and a mouthpiece, the mouthpiece comprising a proximal portion for insertion into a user’s mouth, in which the aerosolforming substrate has a length dimension that is greater than or equal to a width dimension, and a width dimension that is greater than a thickness dimension, and in which the proximal portion of the mouthpiece has a major axis dimension which is greater than the width dimension of the aerosol-forming substrate.

[0089] Exvi. An aerosol-generating article, for example an aerosol-generating article according to any preceding example, comprising an aerosol-forming substrate and a mouthpiece, the mouthpiece comprising a proximal portion for insertion into a user’s mouth, in which the aerosolforming substrate has a length dimension that is greater than or equal to a width dimension, and a width dimension that is greater than a thickness dimension, and in which the proximal portion of the mouthpiece has a transverse cross-section which has a greater area than a transverse cross-section of the aerosol-forming substrate, the transverse cross-section of the substrate and the mouthpiece being cross-sections taken perpendicular to the length dimension of aerosolforming substrate.

[0090] Exvii. An aerosol-generating article, for example an aerosol-generating article according to any preceding example, comprising an aerosol-forming substrate and a mouthpiece, in which the mouthpiece comprises a proximal portion for insertion into a user’s mouth and a distal portion comprising a recess dimensioned for engagement with the aerosol-forming substrate, in which an airflow path is defined through the mouthpiece between the distal portion and the proximal portion, and in which the aerosol-forming substrate has a length dimension that is greater than or equal to a width dimension, and a width dimension that is greater than a thickness dimension.

[0091] Ex1 . An aerosol-generating article, for example an aerosol-generating article according to any preceding example, comprising an aerosol-forming substrate and a mouthpiece, in which the mouthpiece comprises a proximal portion for insertion into a user’s mouth and a distal portion configured for engagement with the aerosol-forming substrate, in which an airflow path is defined by an airflow channel passing through the mouthpiece between the distal portion and the proximal portion, and in which the airflow channel comprises a first constriction portion and a first expansion portion downstream of the first constriction portion.

[0092] Ex2. An aerosol-generating article according to Ex1 in which the airflow channel tapers or funnels inwards towards the first constriction portion.

[0093] Ex3. An aerosol-generating article according to Ex1 or Ex2 in which the airflow channel tapers or funnels outwards away from the first constriction portion, towards the first expansion portion.

[0094] Ex4. An aerosol-generating article according to any of Ex1 to Ex3 in which the airflow path further comprises a second constriction portion downstream of the first expansion portion.

[0095] Ex5. An aerosol-generating article according to Ex4 in which the airflow channel tapers or funnels inwards towards the second constriction portion.

[0096] Ex6. An aerosol-generating article according to Ex4 or Ex5 in which the airflow channel tapers or funnels outwards away from the second constriction portion.

[0097] Ex7. An aerosol-generating article according to any of Ex4 to Ex6 in which the airflow path further comprises a second expansion portion downstream of the second constriction portion.

[0098] Ex8. An aerosol-generating article according to Ex7 in which an airflow outlet is defined at the second expansion portion.

[0099] Ex9. An aerosol-generating article according to any of examples Ex1 to Ex8 in which a collection chamber is defined by the mouthpiece, the collection chamber being located downstream of the aerosol-forming substrate and upstream of the first constriction portion.

[0100] Ex10. An aerosol-generating article according to any preceding example in which the aerosol-forming substrate is a substantially planar substrate, for example in which the aerosolforming substrate is substantially parallelepiped shaped, for example substantially cuboid shaped.

[0101] Ex11. An aerosol-forming article according to any preceding example in which the aerosol-forming substrate has a length defined by an x dimension extending in an x direction, a width defined by a y dimension extending in a y direction, and a thickness defined by a z dimension extending in a z direction.

[0102] Ex12. An aerosol-generating article according to any preceding example in which the thickness of the aerosol-forming substrate is between 1 mm and 5 mm, for example between 1.2 mm and 4.7 mm, for example between 2 mm and 4 mm, for example about 1 .5 mm, or about 2.5 mm, or about 3 mm, or about 4 mm.

[0103] Ex13. An aerosol-generating article according to any preceding example in which the length of the aerosol-forming substrate is between 10 mm and 35 mm, for example between 24 mm and 31 mm, for example between 20 mm and 25 mm, for example about 14 mm, or about 20 mm, or about 25 mm, or about 31 mm.

[0104] Ex14. An aerosol-generating article according to any preceding example in which the width of the aerosol-forming substrate is between 5 mm and 25 mm, for example between 9 mm and 21 mm, for example between 12 mm and 16 mm, for example about 9 mm, or about 12 mm, or about 15 mm, or about 20 mm.

[0105] Ex15. An aerosol-forming article according to any preceding example in which the aerosol-forming substrate has a thickness to width ratio of between about 0.13:1 to 0.22:1.

[0106] Ex16. An aerosol-forming article according to any preceding example in which the aerosol-forming substrate has a length to width ratio of between about 1.55:1 to 1.48:1.

[0107] Ex17. An aerosol-generating article according to any preceding example in which the aerosol-forming substrate comprises two or more layers, for example two or more layers laminated together, for example in which the aerosol-forming substrate comprises at least a first planar layer forming an upper surface of the aerosol-forming substrate and a second planar layer forming a lower surface of the aerosol-forming substrate.

[0108] Ex18. An aerosol-generating article according to example Ex17 in which the aerosolforming substrate comprises a first planar layer, a second planar layer, and an intermediate layer or separation layer arranged between the first planar layer and the second planar layer, at least one of the first planar layer, the second planar layer and the intermediate or separation layer comprising or consisting of an aerosol-forming material.

[0109] Ex19. An aerosol-generating article according to example Ex18 in which the intermediate layer or the separation layer is a corrugated layer, for example in which the aerosol-forming substrate comprises a first planar layer, a second planar layer, and a corrugated layer arranged between the first planar layer and the second planar layer, at least one of the first planar layer, the second planar layer and the corrugated layer comprising or consisting of an aerosol-forming material.

[0110] Ex20. An aerosol-generating article according to example Ex19 in which corrugations are arranged perpendicular to the width direction of the aerosol forming substrate and parallel to the length direction of the aerosol-forming substrate.

[0111] Ex21 . An aerosol- generating article according to any preceding example in which an air flow path is defined through the aerosol-forming substrate, for example in which a low resistance air-flow path is defined through the substrate, for example in which the aerosol-forming substrate has a resistance to draw (RTD), along the air-flow path, of less than 20 millimetre H2O. Ex22. An aerosol-generating article according to any preceding example in which an air flow path extends through the substrate in its x dimension from end to the other end, for example in which the air flow path extends substantially in the x direction.

[0112] Ex23. An aerosol-generating article according to any preceding example configured to be coupled to an aerosol-generating device for generating an aerosol.

[0113] Ex24. An aerosol-generating article according to any preceding example in which the aerosol-forming substrate is configured to be received in a heating cavity of an aerosol-generating device, for example in which a portion of the mouthpiece is configured to engage with a portion of the aerosol-generating device to locate the aerosol-forming substrate within the heating cavity.

[0114] Ex25. An aerosol-generating article according to Ex24 in which the distal portion of the mouthpiece engages with an opening to the heating cavity of the aerosol-forming device, for example in which there is a mechanical interaction between the distal portion of the mouthpiece and the opening to the heating cavity, for example in which there is an interference fit between the distal portion of the mouthpiece and the opening to the heating cavity, and / or in which there is a mechanical fastening fit between the distal portion of the mouthpiece and the opening to the heating cavity.

[0115] Ex26. An aerosol-generating article according to any preceding example in which the aerosol-forming substrate has a substantially rectangular transverse cross-section, the transverse cross-section being the cross-section taken perpendicular to the length dimension of the aerosolforming substrate.

[0116] Ex27. An aerosol-generating article according to any preceding example in which the mouthpiece comprises a recess having a shape substantially the same as the transverse crosssection of the aerosol-forming substrate, the transverse cross-section being the cross-section taken perpendicular to the length dimension of the aerosol-forming substrate, for example in which a collection chamber is defined at a proximal end of the recess.

[0117] Ex28. An aerosol- generating article according to Ex27 in which the recess is dimensioned to form a mechanical interaction with the aerosol-forming substrate to couple the aerosol-forming substrate to the mouthpiece, for example in which the recess defines a ridge or lip for engaging with the aerosol-forming substrate, and / or in which the recess is dimensioned to provide an interference fit with the aerosol-forming substrate.

[0118] Ex29. An aerosol- generating article according to Ex27 or Ex28 in which the airflow path through the mouthpiece is defined by an airflow channel, an inlet of the airflow channel being defined within the recess and an outlet of the airflow channel being defined in the proximal portion of the mouthpiece, for example in which air passing along the airflow path between the inlet and the outlet passes through the first constriction portion and then the first expansion portion before passing through the outlet. Ex30. An aerosol- generating article according to any preceding example in which the mouthpiece is formed from biodegradable material, and / or in which the mouthpiece is formed from paper material.

[0119] Ex31. An aerosol- generating article according to any preceding example in which the proximal portion of the mouthpiece is shaped to have an ergonomic fit in a user’s mouth.

[0120] Ex32. An aerosol- generating article according to any preceding example in which the proximal portion of the mouthpiece has a curved transverse cross-sectional shape, for example a curved non-circular cross-sectional shape, for example in which the transverse cross-sectional shape is oval or elliptical or lenticular.

[0121] Ex33. An aerosol-generating article according to any preceding example in which the proximal portion of the mouthpiece has a cross-sectional shape defined by a maximum width and a maximum height, in which the maximum width is between 6 mm and 26 mm, for example between 11 mm and 25 mm, for example between 13 mm and 23 mm, for example about 10 mm, or about 13 mm, or about 16 mm, or about 23 mm.

[0122] Ex34. An aerosol-generating article according to any preceding example in which the proximal portion of the mouthpiece has a cross-sectional shape defined by a maximum width and a maximum height, in which the maximum height is between 4 mm and 15 mm, for example between 5 mm and 13 mm, for example between 6 mm and 9 mm, for example about 5 mm, or about 5 mm, or about 9 mm, or about 13 mm.

[0123] Ex35. An aerosol-generating article according to any preceding example in which a transverse cross-section of the proximal portion of the mouthpiece has a shape defined by a maximum width and a maximum height, in which the ratio of maximum width to maximum height is between 2:1 and 5:1 , for example between 2.5:1 and 4:1 , for example between 3:1 and 3.5:1.

[0124] Ex36. An aerosol-generating article according to any preceding example in which a transverse cross-section of the mouthpiece, for example a proximal portion of the mouthpiece, has an oval, elliptical, or lenticular shape, and a transverse cross-section of the aerosol-forming substrate has a rectangular cross-section.

[0125] Ex37. An aerosol-generating article according to any preceding example in which a transverse cross-section of the mouthpiece, for example a proximal portion of the mouthpiece, has a curved non-circular shape defined by a major axis and a minor axis, in which a ratio of the maximum dimension of the major axis to the maximum dimension of the minor axis is between 1.5:1 and 5.5:1 , for example between 2:1 and 5:1 , for example between 2.5:1 and 4:1 , for example between 3:1 and 3.5:1.

[0126] Ex38. An aerosol-generating article according to any preceding example in which the mouthpiece has a length of between 10 mm and 25 mm, for example between 12 mm and 21 mm. Ex39. An aerosol-generating article according to any preceding example comprising a mouthpiece and a planar aerosol-forming substrate coupled to the mouthpiece, in which the planar aerosol-forming substrate comprises a planar frame positioned between an upper layer and a lower layer, the upper surface defining an external surface of the upper layer and the lower surface defining an external surface of the lower layer, the planar frame defining a cavity, wherein an air flow path is defined through the aerosol-generating article in an x / y plane, the air-flow path extending through the cavity and the mouthpiece.

[0127] Ex40. An aerosol-generating article according to Ex39, wherein the upper layer and the lower layer are coupled to opposing surfaces of the frame to overlie opposing ends of the cavity.

[0128] Ex41. An aerosol-generating article according to either one of Ex39 or Ex40, wherein one or both of the upper layer and the lower layer comprise or consist of aerosol-forming substrate.

[0129] Ex42. An aerosol-generating article according to anyone of Ex39 to Ex41 , wherein the upper layer and the lower layer are free of aerosol-forming substrate.

[0130] Ex43. An aerosol-generating article according to any one of Ex39 to Ex42, wherein the frame is free of aerosol-forming substrate.

[0131] Ex44. An aerosol-generating article according to any one of Ex39 to Ex43, comprising one or more of particles, shreds, or a sheet of aerosol-forming substrate disposed within the cavity between the upper and lower layers.

[0132] Ex45. An aerosol-generating article according to any one of Ex39 to Ex44, wherein a corrugated element is disposed within the cavity between the upper and lower layers.

[0133] Ex46. An aerosol-generating article according to Ex45, wherein the corrugated element comprises or consists of aerosol-forming substrate.

[0134] Ex47. An aerosol-generating article according to Ex45, wherein the corrugated element is free of aerosol-forming substrate.

[0135] Ex48. An aerosol-generating article according to any one of Ex45 to Ex47, wherein a plurality of longitudinally extending channels are defined by corrugations between the upper layer and the corrugated element and between the corrugated element and the lower layer.

[0136] Ex49. An aerosol-generating article according to Ex48, wherein the longitudinally extending channels extend along in an x / y plane between opposing ends of the frame.

[0137] Ex50. An aerosol-generating article according to any one of Ex39 to Ex49, wherein the air-flow path is at least partially defined by the frame.

[0138] Ex51 . An aerosol-generating article according to Ex50, wherein the frame comprises an inlet air-flow channel and an outlet air-flow channel, the inlet air-flow channel configured to permit a flow of air into the cavity and the outlet air-flow channel configured to permit a flow of air to exit the cavity and pass thorough the mouthpiece. Ex52. An aerosol-generating article according to Ex51 , wherein the inlet air-flow channel and the outlet air-flow channel are defined on opposing ends of the frame.

[0139] Ex53. An aerosol-generating article according to either one of Ex51 or Ex52, wherein the inlet air-flow channel is defined in a first width edge of the frame and the outlet air-flow channel is defined in a second width edge of the frame.

[0140] Ex54. An aerosol-generating article according to any of examples Exi to Ex38 comprising a mouthpiece and a planar aerosol-forming substrate coupled to the mouthpiece, in which the planar aerosol-forming substrate comprises an intermediate layer arranged between an upper layer and a lower layer, the upper surface defining an external surface of the upper layer and the lower surface defining an external surface of the lower layer, wherein an air flow path is defined through the aerosol-generating article in an x / y plane between a distal end and a proximal end of the aerosol-generating article.

[0141] Ex55. An aerosol-generating article according to Ex54, wherein a resistance to draw (RTD) of the aerosol-generating article, along the air-flow path, is less than 20 millimetre H2O, for example less than 15 mm H2O, or less than 10 mm H2O.

[0142] Ex56. An aerosol-generating article according to either one of Ex54 or Ex55, wherein one or more of the upper layer, the intermediate layer and the lower layer comprise or consist of aerosol-forming substrate.

[0143] Ex57. An aerosol-generating article according to Ex56, wherein one or both of the upper layer and the lower layer comprise or consist of aerosol-forming substrate, the intermediate layer being free of aerosol-forming substrate.

[0144] Ex58. An aerosol-generating article according to Ex56, wherein the intermediate layer comprises or consists of aerosol-forming substrate, the upper layer and the lower layer being free of aerosol-forming substrate.

[0145] Ex59. An aerosol-generating article according to any one of Ex54 to Ex58, wherein a plurality of longitudinally extending channels are defined by corrugations between the upper layer and the intermediate layer and between the intermediate layer and the lower layer.

[0146] Ex60. An aerosol-generating article according to Ex59, wherein the longitudinally extending channels extend along in an x / y plane between the distal end and the proximal end.

[0147] Ex61. An aerosol-generating article according to any one of Ex54 to Ex60, wherein the intermediate layer is fixed relative to at least one of the upper layer and lower layer by an adhesive, for example in which the adhesive comprises guar gum, optionally in which the adhesive comprises an aerosol-forming material such as homogenised tobacco slurry.

[0148] Ex62. An aerosol-generating article according to any one of Ex54 to Ex61 , wherein the intermediate layer comprises a corrugated element.

[0149] Ex63. An aerosol-generating article according to Ex62, wherein the intermediate layer comprises a plurality of corrugated elements, in which two or more of the plurality of corrugated elements are arranged in vertical relationship to each other between the upper layer and the lower layer.

[0150] Ex64. An aerosol-generating article according to Ex63, wherein one or more of the plurality of corrugated elements comprise aerosol-forming substrate.

[0151] Ex65. An aerosol-generating article according to either one of Ex63 or Ex64, wherein the intermediate layer further comprises a planar element positioned between two of the plurality of corrugated elements.

[0152] Ex66. An aerosol-generating system comprising an aerosol-generating article according to any preceding example and an aerosol-generating device configured to receive the aerosolgenerating article.

[0153] Ex67. An aerosol-generating system according to Ex66 in which the aerosol-generating device is configured to generate an inhalable aerosol from at least a portion of the aerosolgenerating article, for example in which the aerosol-generating device is configured to heat at least a portion of the aerosol-generating article to form an inhalable aerosol.

[0154] Ex68. An aerosol-generating system according to Ex66 or Ex67 in which the aerosolgenerating device comprises a heater located within a chamber for receiving the aerosol-forming substrate of the aerosol-generating article.

[0155] Ex69. An aerosol-generating system according to Ex68 in which the mouthpiece of the aerosol-generating article is configured to mechanically engage with the aerosol-generating device such that the aerosol-forming substrate is received within the chamber for heating.

[0156] Ex70. An aerosol-generating system according to any of Ex66 to Ex69 in which the aerosol-generating device comprises an air inlet, an airflow path being defined such that when a user draws on the mouthpiece air flows into the device, through the aerosol-forming substrate, through the first constriction portion of the mouthpiece, through the first expansion portion of the mouthpiece, and into the mouth of the user.

[0157] Examples will now be further described with reference to the figures in which:

[0158] Figure 1 is a perspective side view of an aerosol-forming substrate suitable for use as part of an aerosol-generating article according to an embodiment of the present disclosure;

[0159] Figure 2 is a perspective side view of a further aerosol-forming substrate ;

[0160] Figure 3 is a schematic end view of a further aerosol-forming substrate;

[0161] Figure 4 is a schematic side view of the aerosol-forming substrate of figure 3;

[0162] Figure 5 is a schematic plan view of the aerosol-forming substrate of figure 3;

[0163] Figure 6 shows a schematic illustration of a corrugated element as used in the aerosolforming substrate of figure 3;

[0164] Figure 7 shows a perspective view of a further aerosol-forming substrate;

[0165] Figure 8 shows an exploded perspective view of the aerosol-forming substrate of Figure 7; Figure 9 shows a further exploded perspective view of the aerosol-forming substrate of Figure 7;

[0166] Figure 10 shows a schematic transverse cross-sectional view of the aerosol-forming substrate of Figure 7;

[0167] Figure 11 shows a schematic longitudinal cross-sectional view of the aerosol-forming substrate of Figure 7;

[0168] Figure 12 shows an exploded perspective view of a further aerosol-forming substrate ;

[0169] Figure 13 shows a schematic transverse cross-sectional view of the aerosol-forming substrate of Figure 12;

[0170] Figure 14 shows a schematic lateral cross-sectional view of the aerosol-forming substrate of Figure 12;

[0171] Figure 15 shows a perspective view from the distal end of an aerosol-generating article according to an embodiment of the invention;

[0172] Figure 16 shows a perspective view from the proximal end of the aerosol-generating article of figure 15;

[0173] Figure 17 shows a perspective view of a mouthpiece portion of the aerosol-generating article of figure 15;

[0174] Figure 18 shows a cut-away view of the aerosol-generating article of figure 15;

[0175] Figure 19 shows the aerosol-generating article of figure 15 being inserted into an aerosolgenerating device;

[0176] Figure 20 shows the aerosol-generating article of figure 15 when inserted into the aerosolgenerating device;

[0177] Figure 21 shows a cut-away view of the aerosol-generating article of figure 15 when inserted into the aerosol-generating device;

[0178] Figure 22 shows a perspective view from the distal end of a further aerosol-generating article according to an embodiment of the invention; and

[0179] Figure 23 shows a perspective view from the proximal end of the aerosol-generating article of figure 22.

[0180] Specific examples of aerosol-generating articles comprising a substantially planar aerosolforming substrate portion and a mouthpiece are described below. Specific examples of planar aerosol-forming substrates suitable to be used in such articles are described in relation to figures 1 to 14 below.

[0181] Figure 1 illustrates a perspective side view of a planar aerosol-forming substrate 100 for use in an aerosol-generating article according to an embodiment of the present disclosure. The aerosol-forming substrate 100 has upper and lower surfaces 110, 120 which are flat or planar.

[0182] In one embodiment, the aerosol-forming substrate 100 may consist substantially of aerosolforming material. In another embodiment, the aerosol-forming material, for example homogenised tobacco, may be one of a plurality of component parts of the aerosol-forming substrate 100. The aerosol-forming material may be enclosed within an interior of the aerosol-forming substrate 100. The aerosol-forming substrate 100 may at least partially define an exterior of an aerosolgenerating article; for example, one or both of the upper and lower surfaces 110, 120 may comprise or consist of aerosol-forming material.

[0183] A suitable aerosol-forming material may be homogenised tobacco.

[0184] The aerosol-forming substrate 100 has a length, extending in an x dimension, of 80 millimetres, a width, extending in a y dimension, of 15 millimetres, and a height (which may also be referred to as a thickness), extending in a z dimension, of 3.6 millimetres.

[0185] Figure 2 illustrates a perspective side view of an aerosol-forming substrate 200. Features in common with aerosol-forming substrate 100 are referred to with like reference signs. An air flow path 230 is defined through the aerosol-forming substrate 200 between the upper and lower surfaces 110, 120. The air flow path 230 extends between opposed first and second ends 201 , 202 of the aerosol-forming substrate 200. The first end 201 may define a distal end of the aerosolforming substrate 200, and the second end 202 may define a proximal end of the aerosol-forming substrate . The air flow path 230 may be directed towards a mouth of a user to allow a user to inhale aerosol generated in consequence of heating of aerosol-forming material of the aerosolforming substrate 200.

[0186] Figures 3, 4, and 5 illustrate respectively an end view, a side view, and a plan view of an aerosol-forming substrate 300. The aerosol-forming substrate 300 comprises a planar upper layer 310, a planar lower layer 320, and an intermediate or separation layer 340 arranged between the upper layer 310 and lower layer 320.

[0187] The planar upper layer 310 is formed from a sheet of paper having a thickness of 300 microns. The planar lower layer 320 is formed from a sheet of paper having a thickness of 300 microns. The intermediate layer 340 is a corrugated element formed from a corrugated sheet of aerosol-forming material 345. A suitable aerosol-forming material may be homogenised tobacco. Thus, the intermediate layer 340 may be formed from a corrugated sheet of homogenised tobacco material 345.

[0188] Figure 6 illustrates the corrugated sheet of aerosol-forming material 345. The corrugations have an amplitude 346 of 3 millimetres and a wavelength 347 of 3 millimetres. The sheet of aerosol-forming material 345 forming the intermediate layer 340 has a thickness of 150 microns.

[0189] Points of intersection 351 , 352 between the upper layer 310 and the intermediate layer 340 and between the lower layer 320 and the intermediate layer 340 comprise an adhesive that joins the respective layers.

[0190] The aerosol-forming substrate 300 has a length, extending in an x dimension, of 80 millimetres, a width, extending in a y dimension, of 15 millimetres, and a height (or thickness), extending in a z dimension, of 3.6 millimetres. Corrugations of the intermediate layer 340 form a first set of longitudinally extending channels 361 that are bounded by the upper layer 310 and the intermediate layer 340, and a second set of longitudinally extending channels 362 bounded by the lower layer 320 and the intermediate layer 340. The first and second sets of longitudinally extending channels 361 , 362 extend through the length of the aerosol-forming material between a proximal end 371 of the material 345 and a distal end 372 of the material 345. The longitudinally extending channels 361 , 362 define an air-flow path through the substrate 300. The air-flow path, therefore, passes over both sides of the sheet of aerosol-forming material 345. The porosity of the aerosol-forming substrate along the air-flow path is in the region of 90 %. This provides a very low resistance to draw (RTD) of less than 5 mm H2O. In fact, the RTD is close to zero.

[0191] The aerosol-forming material 345 may be a sheet of any suitable aerosol-forming material.

[0192] During use of an aerosol-generating article comprising the aerosol-forming substrate 300, the aerosol-forming material 345 is heated up to cause the aerosol-forming material 345 to release volatile compounds, which are then entrained in air drawn into the channels 361 , 362 via the distal end 372. The volatile compounds then cool and condense to form an aerosol which may be drawn out of the channels 361 , 362 of the aerosol-forming substrate 300 via the proximal end 371.

[0193] Figure 7 shows an aerosol-forming substrate 400. The aerosol-forming substrate 400 comprises a first planar external layer 424 forming a first planar external surface 421 , a second planar external layer 425 forming a second planar external surface 422, and a frame 450 positioned between the first planar external layer 424 and the second planar external layer 425. The second planar external surface 422 is positioned parallel to the first planar external surface 421.

[0194] Figures 8 and 9 show exploded views of the aerosol-forming substrate 400 of Figure 7. The frame 450 circumscribes and at least partially defines a cavity 430. Figure 8 shows the cavity 430 in an empty state. Figure 9 shows the cavity 430 filled with aerosol-forming material 440. Figures 10 and 11 show respective transverse and longitudinal cross-sectional views of the aerosolforming substrate 400 when the cavity 430 is filled with aerosol-forming material 440.

[0195] The first planar external layer 424 and the second planar external layer 425 are made from cigarette paper having a thickness of 35 micrometres and are in physical contact, with and bonded to, the frame 450. The first planar external layer 424 overlies a first end of the cavity 430 and forms a first cavity end wall 431. The second planar external layer 425 overlies a second end of the cavity 430 and forms a second cavity end wall 432, the second cavity end wall 432 being opposite to the first cavity end wall 431 . That is, the frame 450, the first planar external layer 424 and the second planar external layer 425 collectively define the cavity 430.

[0196] The frame 450 has a hollow cuboid shape and is made from cardboard. The frame 450 defines an aperture extending through the height (also referred to as the thickness) of the frame 450 and the aperture at least partially forms the cavity 430 of the aerosol-forming substrate 400. The frame 450 comprises a peripheral wall 451 that circumscribes the cavity 430. The peripheral wall 451 includes a front wall 413 and a back wall 414. In more detail, the peripheral wall 451 is defined by an inner transverse surface 452 of the frame 450 and an outer transverse surface 453 of the frame 450. The inner transverse surface 452 of the peripheral wall

[0197] 451 at least partially defines a perimeter of the cavity 430. The outer transverse surface 453 of the peripheral wall 451 at least partially defines a perimeter of the aerosol-forming substrate 400. The peripheral wall 451 has a radial thickness measured between the inner transverse surface

[0198] 452 of the frame 450 and the outer transverse surface 453 of the frame 450 of about 5 millimetres.

[0199] An air inlet 411 and an air outlet 412 are defined by, and extend through, the peripheral wall 451 of the frame 450. More specifically, the air inlet 411 extends through the front wall 413 and the air outlet 412 extends through the back wall 414. The air inlet 411 and the air outlet 412 have an equivalent diameter of 5 millimetres. An airflow passage extends between the air inlet 411 and the air outlet 412 through the cavity 430. As shown in Figures 9 to 11 , an aerosol-forming material 440 is positioned within the cavity 430. The aerosol-forming material 440 comprises tobacco cut filler and has an aerosol-former content of 5 percent by weight on a dry weight basis. As shown, the aerosol-forming material 440 fills the entire volume of the cavity 430.

[0200] The aerosol-forming substrate 400 has a cuboid shape and has a height (or thickness) extending in a z dimension, as measured between the first planar external surface 421 and the second planar external surface 422, of 8 millimetres, a width extending in a y dimension of 40 millimetres and a length extending in an x dimension of 60 millimetres. The frame 450 has a height (or thickness) extending in a z dimension of 7.93 millimetres, a width extending in a y dimension of 40 millimetres and a length extending in an x dimension of 60 millimetres. The cavity 430 has a height (or thickness) extending in a z dimension of 7.93 millimetres, a width extending in a y dimension of 39.93 millimetres and a length extending in an x dimension of 52 millimetres.

[0201] Figure 12 shows a further example of an aerosol-forming substrate 500. Features in common with aerosol-forming substrate 400 are referred to with like reference signs. Aerosolforming substrate 500 differs from aerosol-forming substrate 400 in that the aerosol-forming material is in the form of a sheet of aerosol-generating material 540, in particular a corrugated sheet of homogenised tobacco material. Figures 13 and 14 show respective transverse and lateral cross-section views of the aerosol-forming substrate 500 of Figure 12.

[0202] The corrugated sheet of homogenised tobacco material 540 comprises a plurality of parallel corrugations having a plurality of substantially parallel peaks 543 and troughs 544. The plurality of parallel corrugations are defined by a corrugation profile which, as seen in Figure 13, is sinusoidal. The plurality of parallel corrugations have a corrugation wavelength of about 4.6 millimetres. The corrugation amplitude is approximately the same as the height (or thickness) of the cavity 430, as shown by the peaks 543 and troughs 544 coinciding with the first cavity end wall 431 and the second cavity end wall 432, respectively.

[0203] The plurality of parallel corrugations form a plurality of channels 545 between the sheet of aerosol-generating material 540 and the first cavity end wall 431 , and a plurality of channels 546 between the sheet of aerosol-generating material 540 and the second cavity end wall 432. The plurality of channels 545, 546 extend in a longitudinal direction of the aerosol-forming substrate 500 and form at least a portion of the airflow passage extending between the air inlet 411 and the air outlet 412.

[0204] During use of each of the aerosol-forming substrates 400, 500, the aerosol-forming material 440, 540 is heated up to release volatile compounds, which are then entrained in air drawn through the air inlet 411 into the cavity 430. The volatile compounds then cool and condense to form an aerosol which may be drawn out of the aerosol-forming substrate 400, 500 through a mouthpiece coupled to the air outlet 412.

[0205] For exemplary purposes applicable to any of the embodiments described above, a composition of a suitable aerosol-forming material may be as follows. Percentages are given in weight percent with respect to the product in its final state. The aerosol-forming material may have a moisture of about 5 to 25%, preferably of about 7 to 15%, at final product state. The aerosolforming material may further comprise the following:

[0206] Tobacco leaf; for example about 15 to 45%, preferably of about 20 to 35% of a blend of tobacco leaf, incorporating at least one of the following tobacco types: bright tobacco; dark tobacco; aromatic tobacco. Tobacco material is ground and graded to a particle size of about 100 to 380 mesh, preferably of about 170 to 320 mesh.

[0207] Cellulose fibres; for example about 1 to 15%, preferably of about 3 to 7%, of cellulose fibres, of a length of about 10 to 250 pm, preferably of about 10 to 120 pm.

[0208] Tobacco fibres; for example about 5 to 20%, preferably of about 7 to 15% of tobacco fibres, as filler, of any tobacco type or a blend of tobacco types. Tobacco fibres are preferably derived from stems and / or stalks, graded to fibres of a length of about 10 to 350 pm, preferably of about 10 to 180 pm.

[0209] Binder; for example about 1 to 10%, preferably of about 1 to 5%, of a binder such as any of common gums or pectins used in food and beverage (F&B) industries. Preferred binders may be natural pectins, such as fruit, for example citrus, or tobacco pectins; guar gums, land locust bean gums, such as hydroxyethyl and / or hydroxypropyl of those; starches, such as modified or derivatized starches; alginate; methyl, ethyl, ethylhydroxymethyl and carboxymethyl, celluloses; dextran; and xanthan gum. The preferable binder is guar.

[0210] Aerosol-former; for example about 5 to 35%, preferably of about 10 to 25%, of an aerosol former. Suitable aerosol-formers known in the art include: glycerine; monohydric alcohols like menthol, polyhydric alcohols, such as triethylene glycol; esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyls of those.

[0211] “Tobacco type” means one of the different varieties of tobacco, for example based on the distinct curing process that the tobacco undergoes before it is further processed in a tobacco product.

[0212] For exemplary purposes, a composition of a further aerosol-forming material, which may also be suitable for use as the aerosol-forming substrate in any of the embodiments described above is described below. Percentages are given in weight percent with respect to the product in its final state. The aerosol-forming substrate may comprise:

[0213] An aerosol-former such as Glycerin; for example about 10 to 40 %, preferably of about 20 to 30 %.

[0214] Organic fibres; for example about 10 to 30 %, preferably of about 15 to 25%, of any botanical variety suitable and with purity to comply with applicable FDA F&B grade requirements, as commonly available in the market. For example, organic fibres may derive from cellulose, cotton, wood, tea botanical varieties as sub-products, and sub-processed waste, of F&B tea industry. Organic fibres are preferably of a length of about 10 to 400 pm, preferably of about 10 to 200 pm.

[0215] Organic botanical glycerite; for example about 15 to 55 %, preferably of about 20 to 35 %, of botanicals such as Clove, Echinacea sp., Fennel, Ginger, Hawthorn berry, Elderberry, Monarda, Mullein leaves, Nettle, Plantain, Turmeric, Yarrow, and compounds of those.

[0216] Organic botanical extracts; for example about 1 to 15 %, preferably of about 2 to 7 %, of any of the previously referred botanicals, as well as menthol (dl-Menthol, C10H20O, 2-lsopropyl- 5-methylcyclohexanol) such as obtained from Chaerophyllum macrospermum, Mesosphaerum sidifolium, or other related botanic varieties, as well as P-menthan-3-ol, as any secondary alcohol as diastereoisomers of 5-methyl-2-(propan-2-yl)cyclohexan-1-ol.

[0217] Alternatively, such aerosol-forming material may also contain botanical essential oils of about 0.5 to 5 %, preferably of about 1 to 3 %, such as of palm, coconut, and wooden-based essential oils.

[0218] Any of the aerosol-forming substrates described above in relation to figures 1 to 14 may be combined with a mouthpiece to form an aerosol-generating article according to one or more aspects of the present invention. Such aerosol-generating articles will now be described with reference to figures 15 to 20.

[0219] Figures 15 and 16 are schematic perspective illustrations of an aerosol-generating article 1000 according to an embodiment of the invention. Figure 15 illustrates the article 1000 viewed from its distal end, and figure 16 illustrates the same article viewed from its proximal end. Figure 17 is a schematic perspective view of a mouthpiece 1600 of the article 1000.

[0220] The aerosol-generating article 1000 comprises a planar aerosol-forming substrate 1100 coupled to the mouthpiece 1600. The planar aerosol-forming substrate 1100 may be any suitable substrate, for example any one of the substrates 100, 200, 300, 400, 500 described above. The aerosol-forming substrate 1100 comprises an aerosol-forming material and has an air flow channel defined through a length of the substrate 1100, between an airflow channel inlet 1112 and an airflow channel outlet (not shown) to allow air to be drawn through the substrate 1100. A specific example of the aerosol-forming substrate 1100 has a length of 30 mm, a width of 10 mm, and a thickness of 3 mm.

[0221] The mouthpiece 1600 has a distal portion 1601 that is ergonomically shaped to fit a user’s lips. The mouthpiece 1600 has an airflow channel defined therethrough between a distal face 1615 and a proximal face 1616, the distal portion 1601 terminating in an airflow opening or outlet 1620 for allowing a user to draw air through the mouthpiece.

[0222] As can be seen in figure 17, the distal face 1615 of the mouthpiece 1600 defines a recess 1630 dimensioned to receive a portion of the aerosol-forming substrate 1100 to facilitate coupling between the substrate 1100 and the mouthpiece 1600. When the substrate 1100 and the mouthpiece 1600 are coupled, an airflow path is defined between the airflow channel inlet 1112 of the substrate 1100 and the mouthpiece outlet 1620. The recess 1630 has a rectangular cross section and is dimensioned as a substrate carrier to hold the aerosol-forming substrate 1100. The recess 1630 may include retaining features to prevent a full insertion of the substrate 1100. for example, the recess 1630 may include retention features at its surface to restrain displacement of the substrate 1100 along its main axis.

[0223] Coupling between the substrate 1100 and the mouthpiece 1600 may be effected by a simple interference fit. Coupling may be facilitated by a wrapper, for example a paper wrapper that overlaps a portion of both the substrate 1100 and the mouthpiece 1600.

[0224] The airflow channel through the mouthpiece may be structured to cause turbulence in the air flow. Figure 18 illustrates the aerosol-generating article 1000 with a sectioned mouthpiece 1600 showing the structure of the air flow channel. The substrate 1100 is coupled to the recess 1630 of the mouthpiece 1600.

[0225] The airflow path through the mouthpiece formed will be described upstream to downstream from the recess 1630 to the outlet 1620. When the substrate is coupled to the mouthpiece, a space between the proximal face of the substrate and a rear portion of the recess 1630 forms a chamber, which may be termed an aerosol collection chamber 1640. In use, the aerosol collection chamber 1640 is a space within which volatilised components of the aerosol-forming substrate 1100, which are entrained in an airflow passing through the aerosol-forming substrate, can cool and begin to condense into an aerosol. The airflow path then narrows at a first constriction 1650. Air drawn through the first constriction increases in velocity due to the constriction and, consequently, is lower in pressure. Immediately on passing through the first constriction 1650, the airflow path enters an expansion chamber 1660. The expansion chamber has a greater crosssections area than the first constriction 1650. Air passing into the expansion chamber 1660 slows, increases in pressure, and experiences severe turbulence. As a result, the airflow, with entrained volatile components undergoes a significant mixing. Further, the continued cooling of the airflow and the rapid changes in pressure create conditions for nucleation and formation of aerosol. Upstream of the expansion chamber 1660 the airflow path passes through a second constriction 1670. The second constriction 1670 again constricts and accelerates the airflow before the airflow channel expands once more onto the mouthpiece outlet 1620 from where the aerosol may be discharged.

[0226] The first and second constrictions 1650, 1670 may be the narrowest sections along the airflow path. However, the relative dimensions of the first and second constrictions 1650, 1670 may be selected to provide a specific pressure differential along the airflow path. In particular, the relative dimensions of the first and second constrictions 1650, 1670 may have an impact on the air flow speed and the particle size of the aerosol reaching the outlet 1620 for delivery to a user’s mouth.

[0227] In order to consume an aerosol-forming substrate, the user inserts an aerosol-forming article 1000 comprising the substrate 1100 into an aerosol-generating device 1700 configured to receive the article 1000. As illustrated in figure 19, the aerosol-forming substrate portion 1100 of the article 1000 may be inserted into a substrate receiving cavity 1710 of the aerosol-generating device 1700. Figure 20 illustrates the article 1000 coupled to the device 1700 ready for use.

[0228] Engagement between the article 1000 and device 1700 may be achieved by commonly known engagement elements such as threaded portions, snap fit or press fit members incorporated into the matching surfaces of the receiving cavity 1710 and the article 1000. To ensure a hermetic seal between the article 1000 and the receiving cavity 1710, the article 1000 may include a seal 1655 configured to engage with the device 1700. For example, a seal 1655 may include over-molded material on the perimetry of the distal end 1615 of the mouthpiece 1600.

[0229] Figure 21 is a schematic cross-section of an aerosol-generating device 1700 when engaged with an aerosol-generating article 1000. The device 1700 comprises a housing 1703, which locates a battery 1701 and control electronics 1702. A wall of the substrate receiving cavity 1710 is in thermal communication with a planar heater 1750, for heating an aerosol-forming substrate 1100 received in the cavity 1710.

[0230] When the article 1000 is coupled to the device 1700, the user can activate the device, for example by pressing an activation button. The heater 1750 is activated, thereby heating the aerosol-forming substrate 1100 to an operating temperature sufficient to liberate volatile components of the substrate. As the user draws on the distal portion of the mouthpiece 1600, air is drawn into the aerosol-generating device 1700 and through the aerosol-forming substrate 1100, thereby entraining volatile components of the substrate that have been evolved by the heating. As the air is drawn through the mouthpiece, the air mixes and cools, and an aerosol is generated. The aerosol is delivered to the user through the outlet of the mouthpiece 1600. After the substrate 1100 has been consumed, the user can remove the article 1000 from the device 1700. If the article comprises a re-usable mouthpiece, the user may discard the depleted aerosol-forming substrate 1100 from the mouthpiece and replace with a fresh one. Alternatively, if the article 1000 is manufactured as a single piece product, the user may simply discard and replace with a new article.

[0231] Figures 22 and 23 illustrate a specific example of an aerosol-generating article 2000 having an ergonomically shaped mouthpiece 1800. The aerosol-generating article 2000 comprises a planar aerosol-forming substrate 1100 coupled to the mouthpiece 1800. The planar aerosolforming substrate 1100 may be any suitable substrate, for example any one of the substrates 100, 200, 300, 400, 500 described above. The aerosol-forming substrate 1100 comprises an aerosol-forming material and has an air flow channel defined through a length of the substrate 1100, between an airflow channel inlet 1112 and an airflow channel outlet (not shown) to allow air to be drawn through the substrate 1100. A specific example of the aerosol-forming substrate 1100 has a length of 35 mm, a width of 12 mm, and a thickness of 3.5 mm.

[0232] The mouthpiece 1800 is ergonomically shaped to fit a user’s lips and has an airflow channel defined therethrough, allowing a user to draw air through the mouthpiece 1800. A transverse cross-section of the mouthpiece 1800 is shaped as an ellipse having a major axis corresponding to a width dimension of the aerosol-forming substrate 1100 and a minor axis corresponding to a thickness dimension of the aerosol-forming substrate 1100. The maximum dimension of the major axis is 18 mm and the maximum dimension of the minor axis is 7 mm. The maximum dimension of the major axis of the mouthpiece 1800 is greater than the width of the substrate 1100. By using such a mouthpiece, the dimensions of the aerosol-forming substrate 1100 may be minimised while still allowing user manipulation.

[0233] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term “about”. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number “A” is understood as “A” ± 10% of “A”. Within this context, a number “A” may be considered to include numerical values that are within general standard error for the measurement of the property that the number “A” modifies. The number “A”, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which “A” deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. The terms “in which” and “wherein” are used synonymously through this specification.

Claims

CLAIMS1. An aerosol-generating article comprising an aerosol-forming substrate and a mouthpiece, in which the mouthpiece comprises a proximal portion for insertion into a user’s mouth and a distal portion configured for engagement with the aerosol-forming substrate, in which an airflow path is defined by an airflow channel passing through the mouthpiece between the distal portion and the proximal portion, and in which the airflow channel comprises a first constriction portion and a first expansion portion downstream of the first constriction portion.

2. An aerosol-generating article according to claim 1 in which the airflow path further comprises a second constriction portion downstream of the first expansion portion.

3. An aerosol-generating article according to any preceding claim in which the airflow path further comprises a second expansion portion downstream of the second constriction portion.

4. An aerosol-generating article according to claim 3 in which an airflow outlet is defined at the second expansion portion.

5. An aerosol-generating article according to any preceding claim in which a collection chamber is defined by the mouthpiece, the collection chamber being located downstream of the aerosol-forming substrate and upstream of the first constriction portion.

6. An aerosol-generating article according to any preceding example in which the aerosol-forming substrate is a substantially planar substrate, for example in which the aerosolforming substrate is substantially parallelepiped shaped, for example substantially cuboid shaped.

7. An aerosol- generating article according to any preceding claim in which an air flow path is defined through the aerosol-forming substrate, for example in which a low resistance airflow path is defined through the substrate, for example in which the aerosol-forming substrate has a resistance to draw (RTD), along the air-flow path, of less than 20 millimetre H2O.

8. An aerosol-generating article according to any preceding claim in which the aerosol-forming substrate is configured to be received in a heating cavity of an aerosol-generating device, for example in which a portion of the mouthpiece is configured to engage with a portion of the aerosol-generating device to locate the aerosol-forming substrate within the heating cavity.

9. An aerosol-generating article according to any preceding claim in which the mouthpiece comprises a recess having a shape substantially the same as the transverse crosssection of the aerosol-forming substrate, the transverse cross-section being the cross-section taken perpendicular to the length dimension of the aerosol-forming substrate.

10. An aerosol-generating article according to claim 9 in which a collection chamber is defined at a proximal end of the recess.

11. An aerosol- generating article according to claim 9 or 10 in which the recess is dimensioned to form a mechanical interaction with the aerosol-forming substrate to couple the aerosol-forming substrate to the mouthpiece, for example in which the recess defines a ridge orlip for engaging with the aerosol-forming substrate, and / or in which the recess is dimensioned to provide an interference fit with the aerosol-forming substrate.

12. An aerosol- generating article according to any of claims 9 to 11 in which the airflow path through the mouthpiece is defined by an airflow channel, an inlet of the airflow channel being defined within the recess and an outlet of the airflow channel being defined in the proximal portion of the mouthpiece, for example in which air passing along the airflow path between the inlet and the outlet passes through the first constriction portion and then the first expansion portion before passing through the outlet.

13. An aerosol- generating article according to any preceding claim in which the mouthpiece is formed from biodegradable material, and / or in which the mouthpiece is formed from paper material.

14. An aerosol-generating system comprising an aerosol-generating article according to any preceding claim and an aerosol-generating device configured to receive the aerosolgenerating article.

15. An aerosol-generating system according to claim 14 in which the aerosolgenerating device comprises an air inlet, an airflow path being defined such that when a user draws on the mouthpiece air flows into the device, through the aerosol-forming substrate, through the first constriction portion of the mouthpiece, through the first expansion portion of the mouthpiece, and into the mouth of the user.

16. An aerosol-generating article according to any preceding claim in which the mouthpiece is removably couplable to the aerosol-forming substrate, for example in which the mouthpiece is a reusable mouthpiece designed for use with multiple different aerosol-forming substrates.

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