Aerosol-generating article with cavity

Abstract

There is provided an aerosol-generating article comprising an aerosol-forming material for generating an aerosol. An aerosol-forming article includes a first planar layer extending in a first plane and a second planar layer extending in a second plane, the second plane being parallel to and spaced apart from the first plane. A thickness of the article extends in a direction perpendicular to the first plane and the second plane with a cavity defined between the first planar layer and the second planar layer. A height of the cavity is defined by a distance between a lower surface of the first planar layer and an upper surface of the second planar layer. The aerosol-generating article has a thickness of less than 5 mm, and the height of the cavity is greater than 50% of the thickness of the aerosol-generating article.

Description

[0001] The present disclosure relates to an aerosol-generating article comprising an aerosol-forming material.

[0002] A typical aerosol-generating article may look 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 of which are wrapped in cigarette paper. The dimensions of a typical aerosol-generating article are generally similar to those of a conventional cigarette.

[0003] Studies have shown that in typical aerosol-generating articles comprising a stick of an aerosol-forming substrate, a substantial portion of the stick of the aerosol-forming substrate may not be sufficiently heated during use to form an aerosol. This is undesirable because this portion of the stick of the aerosol-forming substrate affects the manufacturing and shipping costs of the aerosol-generating article, but does not affect the aerosol delivered to the end user. This may be the case regardless of the manner in which the aerosol-forming substrate is heated, for example, whether a resistive heater or an induction heater is used, and whether the stick of the aerosol-forming substrate is heated internally or externally.

[0004] It is an object of the present disclosure to provide an aerosol-generating article in which a major portion of the aerosol-forming substrate of the aerosol-generating article is heated sufficiently to form an aerosol during use.

[0005] According to the present disclosure, an aerosol-generating article may be provided, comprising an aerosol-forming material for generating an aerosol. The aerosol-generating article may comprise a first planar layer extending in a first plane and a second planar layer extending in a second plane, the second plane being parallel to and spaced apart from the first plane. The thickness of the aerosol-generating article may extend in a direction perpendicular to the first plane and the second plane, wherein a cavity is defined between the first planar layer and the second planar layer. The height of the cavity may be defined by the distance between the lower surface of the first planar layer and the upper surface of the second planar layer. The thickness of the aerosol-generating article may be less than 5 mm. The height of the cavity may be greater than 50% of the thickness of the aerosol-generating article.

[0006] According to the present disclosure, an aerosol-generating article may be provided, comprising an aerosol-forming substrate for generating an aerosol, the aerosol-generating article being a planar aerosol-generating article having 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. The aerosol-generating article may comprise a first planar layer extending in a first plane and a second planar layer extending in a second plane, the second plane being parallel to and spaced apart from the first plane. The thickness of the article may extend in a direction perpendicular to the first plane and the second plane, wherein a cavity is defined between the first planar layer and the second planar layer. The height of the cavity may be defined by the distance between a lower surface of the first planar layer and an upper surface of the second planar layer. The thickness of the aerosol-generating article may be less than 5 mm. The height of the cavity may be greater than 50% of the thickness of the aerosol-generating article.

[0007] According to the present disclosure, an aerosol-generating article may be provided, comprising an aerosol-forming substrate for generating an aerosol, the aerosol-generating article comprising a substantially planar upper surface defined by a length extending in the x-direction and a width extending in the y-direction, and a substantially planar lower surface defined by a length extending in the x-direction and a width extending in the y-direction. The substantially planar upper surface and the substantially planar lower surface may be vertically spaced apart from each other by a height defined in the z-direction. The aerosol-generating article may comprise a first planar layer extending in a first plane and a second planar layer extending in a second plane. The first planar layer may comprise the substantially planar upper surface and a lower surface of the first planar layer. The second planar layer may comprise the substantially planar lower surface and an upper surface of the second planar layer. The thickness of the aerosol-generating article may extend in a direction perpendicular to the first and second planes, wherein a cavity is defined between the first and second planar layers. The height of the cavity may be defined by the distance between the lower surface of the first planar layer and the upper surface of the second planar layer. The thickness of the aerosol-generating article may be less than 5 mm. The height of the cavity may be greater than 50% of the thickness of the aerosol-generating article.

[0008] The aerosol-generating articles of the present disclosure may be substantially flat and thin, for example having a thickness of less than 5 mm. Advantageously, providing a substantially flat and thin aerosol-generating article provides for rapid and efficient heating of the aerosol-forming material in the aerosol-generating article and improved uniformity in through-thickness heating.

[0009] Advantageously, the cavity height is relatively high, for example, the cavity height may be greater than 50% of the thickness of the aerosol-generating article. Providing a substantially high cavity height provides space for sufficient airflow through the aerosol-generating article, despite the article being substantially flat and thin. In use, the cavity height may allow air to flow through the cavity more slowly than a cavity having a smaller height, thereby providing improved contact between the airflow and the aerosol-forming material of the aerosol-forming article, enhanced mixing of the generated aerosol with the air in the cavity, and improved aerosolization.

[0010] The thickness of the aerosol-generating article may be defined by the distance between the upper surface of the aerosol-generating article and the lower surface of the aerosol-generating article. For example, the thickness of the aerosol-generating article may be defined between the upper surface of a first planar layer (e.g., the substantially planar upper surface of the first planar layer) and the lower surface of a second planar layer (e.g., the substantially planar lower surface of the second planar layer).

[0011] The first planar layer may include an upper surface of the aerosol-generating article and a lower surface of the aerosol-generating article, wherein the upper surface and the lower surface may be vertically spaced apart from each other by a height defined in the z-direction. The upper surface of the first planar layer may be substantially planar and defined by a length extending in the x-direction and a width extending in the y-direction. The lower surface of the first planar layer may be a substantially planar lower surface and defined by a length extending in the x-direction and a width extending in the y-direction. The upper surface of the first planar layer may be an exterior upper surface of the aerosol-generating article.

[0012] The second planar layer may include an upper surface and a lower surface, wherein the upper surface and the lower surface may be vertically spaced apart from each other by a height defined in the z-direction. The upper surface of the second planar layer may be substantially planar and defined by a length extending in the x-direction and a width extending in the y-direction. The lower surface of the second planar layer may be a substantially planar lower surface and defined by a length extending in the x-direction and a width extending in the y-direction. The lower surface of the second planar layer may be an exterior lower surface of the aerosol-generating article.

[0013] Advantageously, the upper outer surface of the first planar layer and the lower outer surface of the second planar layer allow good contact with an external heater of the aerosol-generating device, in particular a planar external heater, thereby providing optimal heating of the aerosol-generating substrate.

[0014] Advantageously, the upper outer surface of the first planar layer and the lower outer surface of the second planar layer may provide a large surface area for heating by an external heater of the aerosol-generating device, thereby allowing the aerosol-generating substrate to be quickly heated to a temperature sufficient to generate an aerosol.

[0015] 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. Advantageously, a larger base area can provide a larger surface area for heating by the planar heater of the aerosol-generating device. Advantageously, a smaller height can allow for a smaller temperature gradient or temperature 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 the planar heater, if the spacing or height between the base and the upper surface is small, there may be a smaller temperature difference between the base and the upper surface opposite the base. Advantageously, this can allow a larger proportion of the aerosol-forming substrate of the aerosol-generating article to be heated to a temperature at which the aerosol is released, while minimizing the risk of burning the hottest part of the substrate closest to the heater. Alternatively or in addition, this can reduce the time required to sufficiently heat the aerosol-forming substrate to release the aerosol.

[0016] The aerosol-generating article may comprise an airflow inlet, an airflow outlet, and an airflow passage extending between the airflow inlet and the airflow outlet.The airflow passage may extend through the cavity between the air inlet and the air outlet.

[0017] The aerosol-generating article may be defined by an article length extending in the x-direction, an article width extending in the y-direction, and an article thickness extending in the z-direction, wherein an airflow path may be defined through the aerosol-forming article between an airflow inlet and an airflow outlet, the airflow path flowing through the cavity. For example, the airflow path may extend through the cavity between the air inlet and the air outlet.

[0018] The airflow inlet may be defined by an inlet width and an inlet height, wherein the inlet width is greater than 80% of the article width and the inlet height is greater than 25% of the article height, optionally wherein the airflow inlet is substantially rectangular.

[0019] The airflow outlet may be defined by an outlet width and an outlet height, wherein the outlet width is greater than 80% of the article width and the outlet height is greater than 25% of the article height, optionally wherein the airflow outlet is substantially rectangular.

[0020] Advantageously, the air inlet may be sized to facilitate the flow of air into the aerosol-generating article.The air outlet may be sized to facilitate the flow of air out of the aerosol-generating article.

[0021] The height of the cavity may be greater than 60% of the thickness of the article, for example greater than 70% of the thickness of the article, for example greater than 80% of the thickness of the article, preferably greater than 85% of the thickness of the article, or greater than 90% of the thickness of the article, for example greater than 95% of the thickness of the article.

[0022] An airflow inlet may be defined at the distal end of the article, the airflow inlet being configured to allow air to flow into the cavity. An airflow outlet may be defined at the proximal end of the article, the airflow outlet being configured to allow air to flow out of the cavity.

[0023] The aerosol-generating article may further define a mouthpiece, such as an integral mouthpiece or a removable mouthpiece, in fluid communication with the cavity.

[0024] An aerosol-generating article according to any aspect disclosed herein may have an airflow path extending through the aerosol-generating article. The aerosol-generating article may have an airflow path defined as passing through the aerosol-generating article in the x / y plane from one side of the aerosol-generating article to the other side of the aerosol-generating article. The airflow path may be defined as passing through the aerosol-generating article between the distal end and the proximal end of the aerosol-generating article. The airflow path may be defined as passing through the aerosol-generating article from the air inlet, through the cavity, and to the air outlet. The airflow path may be defined as passing through an airflow passageway.

[0025] The resistance to draw (RTD) of the article along the airflow path between the air inlet and the air outlet may be less than 20 mm HO. The aerosol-generating article preferably has a resistance to draw (RTD) of less than 20 mm HO, for example less than 10 mm HO, in the direction of the airflow path. Preferably, the aerosol-generating article has an RTD of less than 20 mm HO, for example less than 10 mm HO, in at least one direction in the x / y plane of the aerosol-generating article. Aerosol-generating articles with a low-resistance airflow path may allow for superior airflow management and allow the aerosol to be more efficiently extracted from the aerosol-generating article and directed to the user.

[0026] Unless otherwise stated, resistance to draw (RTD) is measured in accordance with ISO 6565-2015. RTD refers to the pressure required to force air through the full length of a component, such as an aerosol-generating article. The terms "pressure drop" or "draw resistance" of a component or article may also refer to "resistance to draw". Such terms generally refer to measurements made in accordance with ISO 6565-2015, and the measurements are typically made in a test at a temperature of about 22 degrees Celsius, a pressure of about 101 kPa (about 760 Torr) and a relative humidity of about 60%, with a volumetric flow rate of about 17.5 ml / s at the output or downstream end of the measuring component.

[0027] The aerosol-generating article according to any aspect disclosed herein may comprise a substantially planar upper surface and a lower surface. The vertical separation between the substantially planar upper surface and the lower surface may define the height (e.g., the z-dimension) of the aerosol-generating article. An airflow path may be defined between the substantially planar upper surface and the lower surface. The height of the aerosol-generating article may be less than 5 mm, for example, between 1.5 mm and 5 mm, for example, between 1.5 mm and 4 mm, for example, between 1.5 mm and 3 mm, for example, between 1.5 mm and 2 mm. One or both of the substantially planar upper surface and the lower surface may comprise an aerosol-forming substrate. The aerosol-generating article may comprise an upper layer and a lower layer, at least one of the upper layer and the lower layer comprising or consisting of an aerosol-forming substrate, the upper layer forming the substantially planar upper surface, and the lower layer forming the substantially planar lower surface.

[0028] According to the present disclosure, an aerosol-generating article may be provided, comprising a first planar layer, a second planar layer, and an intermediate layer disposed between the first and second planar layers. The thickness of the aerosol-generating article may extend in a direction perpendicular to the first and second planar layers, wherein a cavity is defined between the first and second planar layers. The height of the cavity may be defined by the distance between the lower surface of the first planar layer and the upper surface of the second planar layer. The thickness of the aerosol-generating article may be less than 5 mm. The height of the cavity may be greater than 50% of the thickness of the aerosol-generating article.

[0029] At least a portion of the intermediate layer may be arranged inside the cavity.Alternatively or additionally, at least a portion of the intermediate layer may be arranged outside the cavity, eg at least a portion of the intermediate layer may at least partially bound the cavity.

[0030] The intermediate layer may be 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 may comprise or consist of an aerosol-forming substrate.

[0031] The intermediate layer may be attached to the first layer by an adhesive. Alternatively or in addition, the intermediate layer may be attached to the second layer by an adhesive. The adhesive may comprise or consist of an aerosol-forming material.

[0032] The plurality of longitudinally extending passages may be defined by corrugations of a corrugated element located within the cavity.A porous element may be located in at least one of the longitudinally extending passages.

[0033] The longitudinally extending passage may extend in the x / y plane between the distal end and the proximal end of the aerosol-generating article.

[0034] The use of corrugated structures in aerosol-generating articles can advantageously allow the production of aerosol-generating articles having very low RTDs while still being rigid enough for handling by the user. Furthermore, the use of corrugated structures can allow the production of low-density, low-RTD aerosol-generating articles using high-speed production methods similar to those used to produce corrugated cardboard.

[0035] According to the present disclosure, an aerosol-generating article may be provided, comprising: a first planar outer surface; a second planar outer surface; a cavity; a frame positioned between the first planar outer surface and the second planar outer surface, the frame at least partially defining the cavity; an aerosol-forming substrate positioned between the first planar outer surface and the second planar outer surface; and an air inlet and an air outlet; and an air flow passage extending through the cavity between the air inlet and the air outlet. The aerosol-generating article may comprise a first planar layer extending in a first plane and a second planar layer extending in a second plane, the second plane being parallel to and spaced apart from the first plane. The thickness of the aerosol-generating article may extend in a direction perpendicular to the first and second planes, wherein the cavity is defined between the first and second planar layers. The height of the cavity may be defined by the distance between the lower surface of the first planar layer and the upper surface of the second planar layer. The thickness of the aerosol-generating article may be less than 5 mm. The height of the cavity may be greater than 50% of the thickness of the aerosol-generating article.

[0036] The first planar layer may include or form a first planar outer surface. The second planar layer may include or form a second planar outer surface. The first planar outer surface may be opposite to a lower surface of the first planar layer. The second planar outer surface may be opposite to an upper surface of the second planar layer.

[0037] The thickness of the aerosol-generating article may be defined between the first planar outer surface and the second planar outer surface.

[0038] The aerosol-generating article may comprise a planar frame positioned between first and second planar layers, preferably wherein the cavity is defined by a lower surface of the first planar layer, an upper surface of the second planar layer and an inner wall of the planar frame.

[0039] Advantageously, the frame may allow the aerosol-generating article to be relatively thin while maintaining structural rigidity.

[0040] The frame may comprise a peripheral wall that at least partially defines or surrounds the cavity.The frame may comprise a peripheral wall that fully defines or surrounds the cavity.

[0041] Advantageously, the peripheral wall allows for a relatively large internal volume of aerosol-generating material for aerosol formation, while providing structural strength to maintain the shape of the aerosol-generating article.

[0042] Optionally, at least one of the first planar layer, the second planar layer and the frame may comprise or consist of an aerosol-forming substrate.

[0043] The cavity may be substantially empty.

[0044] An aerosol-forming substrate may be positioned within the cavity.

[0045] An intermediate layer, such as a corrugated layer, may be positioned within the cavity.

[0046] The aerosol-generating article of any aspect of the present disclosure may have a length (e.g., x-dimension) between 10 mm and 100 mm, or between 15 mm and 55 mm, or between 20 mm and 45 mm, such as between 25 mm and 35 mm, such as about 25 mm, or 28 mm, or 30 mm, or 32 mm. The aerosol-generating article of any aspect of the present disclosure may have a length (e.g., x-dimension) between 10 mm and 50 mm, such as between 12 mm and 30 mm, such as between 14 mm and 26 mm, such as between 16 mm and 24 mm, such as between 18 mm and 22 mm, such as about 18 mm, or about 19 mm, or about 20 mm, or about 21 mm, or about 22 mm.

[0047] The aerosol-generating article may have a width (e.g., y dimension) of between 5 mm and 20 mm, for example between 6 mm and 15 mm, for example between 7.5 mm and 13 mm, for example between 8 mm and 18 mm, for example between 9 mm and 12.5 mm, for example between 10 mm and 16 mm, for example between 11 mm and 15 mm, for example between 12 mm and 14 mm, for example about 9.5 mm, or 10 mm, or 11 mm, or 12 mm, or 13 mm.

[0048] The aerosol-generating article may have a thickness (e.g., z-dimension) of between 0.5 mm and 5 mm, for example, between 1 mm and 4.75 mm, for example, between 1.5 mm and 4.5 mm, for example, between 2 mm and 4 mm, for example, about 2.5 mm, or about 2.75 mm, or about 3 mm. The aerosol-generating article may have a thickness (e.g., z-dimension) of, for example, between 1.2 mm and 8 mm, for example, between 1.4 mm and 7 mm, for example, between 1.6 mm and 6 mm, for example, between 1.7 mm and 5 mm, for example, about 1.7 mm, or about 4.5 mm, or about 2 mm, or about 3 mm, or about 4 mm.

[0049] Advantageously, these thicknesses can provide a small temperature gradient or temperature difference across the thickness of the aerosol-generating substrate during heating. Advantageously, this can allow a greater proportion of the aerosol-generating substrate to be heated to a temperature at which the aerosol is released, while minimizing the risk of burning the hottest portion of the aerosol-generating substrate closest to the heater. Alternatively or additionally, this can reduce the time required to sufficiently heat the aerosol-generating substrate to release the aerosol.

[0050] The height of the cavity may be between 0.25 mm and 4.9 mm, such as between 0.375 mm and 4.5 mm, such as between 0.5 mm and 4 mm, such as between 0.625 mm and 3.5 mm, such as about 2 mm, or about 2.5 mm, or about 2.9 mm.

[0051] The cavity may have a width between 4.75 mm and 19.75 mm, such as between 5.75 mm and 14.75 mm, such as between 7.25 mm and 12.75 mm, such as between 8.75 mm and 12.25 mm, such as about 9.25 mm, or 9.5 mm, or 10.5 mm, or 11.5 mm.

[0052] The thickness of the first planar layer and / or the second planar layer can be between 150 microns and 1000 microns, for example between 250 microns and 800 microns, for example between 300 microns and 600 microns, for example between 350 microns and 500 microns, for example about 200 microns, or about 250 microns, or about 300 microns, or about 350 microns, or about 400 microns.

[0053] When viewed in plan, the aerosol-generating article of any aspect of the present disclosure may have a shape that defines a polygon, a quadrilateral (e.g., a rectangle or square), an oval, or a circle, or a combination thereof. Where the aerosol-generating article comprises a substantially planar upper surface and a lower surface, when viewed in plan, one or both of the upper and lower surfaces may have a shape that defines a polygon, a quadrilateral (e.g., a rectangle or square), an oval, a circle, or a combination thereof. When viewed in plan, the perimeter of the aerosol-generating article may be formed by a plurality of straight sides, a plurality of curved sides, or a combination of straight and curved sides. Where the aerosol-generating article comprises a substantially planar upper surface and a lower surface, when viewed in plan, the perimeter of one or both of the upper and lower surfaces may have a shape that defines a polygon, a quadrilateral (e.g., a rectangle or square), an oval, a circle, or a combination thereof.

[0054] The aerosol-generating article may consist entirely of the aerosol-forming substrate. Alternatively, the aerosol-forming substrate may be one component part of a plurality of component parts of an aerosol-generating article. The aerosol-forming substrate may comprise an aerosol-forming material.

[0055] The first planar layer may include an aerosol-forming material. Alternatively or additionally, the second planar layer may include an aerosol-forming material. For example, the first planar layer may include a homogenized tobacco sheet. Alternatively or additionally, the second planar layer may include a homogenized tobacco sheet.

[0056] Advantageously, the aerosol-forming material may be heated quickly and efficiently by the external heater.

[0057] Preferably, the first planar layer comprises an aerosol-forming layer comprising an aerosol-forming material, and at least one further layer, such as an outer layer or a wrapper layer.

[0058] Preferably, the second planar layer comprises an aerosol-forming layer comprising an aerosol-forming material, and at least one further layer, such as an outer layer or a wrapper layer.

[0059] Optionally, both the first planar layer and the second planar layer comprise an aerosol-forming layer comprising an aerosol-forming material, and at least one further layer, such as an outer layer or a wrapper layer.

[0060] An aerosol-forming material may be located within the cavity.

[0061] The aerosol-forming substrate, in particular the aerosol-forming material, may comprise nicotine. The nicotine may be present in the form of a tobacco material or in the form of a nicotine extract.

[0062] Preferably, the aerosol-forming substrate, in particular the aerosol-forming material, comprises or consists of a homogenised tobacco material, such as reconstituted tobacco material or cast leaf tobacco material.

[0063] 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 held within a porous substrate. The aerosol-forming substrate may comprise a gel aerosol-forming material.

[0064] 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 aerosol formers selected from the group consisting of polyols, such as propylene glycol, polyethylene glycol, triethylene glycol, 1,3-butylene glycol, and glycerol; esters of polyols, 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 preferred for the aerosol former to be or include glycerol.

[0065] The aerosol-forming substrate may comprise at least 1%, 2%, 5%, 10% or 15% by weight of aerosol-forming agent. The aerosol-forming substrate may comprise greater than 15% by weight of aerosol-forming agent, for example greater than 20%, or greater than 25%, or greater than 30%, or greater than 40% or greater than 50% by weight of aerosol-forming agent.

[0066] The aerosol-forming substrate may comprise less than or equal to 30% by weight of aerosol-former, less than or equal to 25% by weight of aerosol-former, or less than or equal to 20% by weight of aerosol-former. In other words, the aerosol-forming substrate may have an aerosol-former content of less than or equal to 30% by weight, less than or equal to 25% by weight, or less than or equal to 20% by weight.

[0067] The aerosol-forming substrate may comprise between 1 wt% and 30 wt% aerosol-former, between 1 wt% and 25 wt% aerosol-former or between 1 wt% and 20 wt% aerosol-former.

[0068] The aerosol-forming substrate may comprise between 5% and 30% by weight of aerosol-former, between 5% and 25% by weight of aerosol-former or between 5% and 20% by weight of aerosol-former.

[0069] The aerosol-forming substrate may comprise between 10% and 30% by weight aerosol-former, between 10% and 25% by weight aerosol-former or between 10% and 20% by weight aerosol-former.

[0070] The aerosol-forming substrate may comprise between 15% and 30% by weight aerosol-former, between 15% and 25% by weight aerosol-former or between 15% and 20% by weight aerosol-former.

[0071] The aerosol-forming substrate may comprise at least 50 wt% aerosol-former, at least 60 wt% aerosol-former or at least 70 wt% aerosol-former.

[0072] The aerosol-forming substrate may comprise less than or equal to 85 wt% aerosol-former, less than or equal to 80 wt% aerosol-former or less than or equal to 75 wt% aerosol-former.

[0073] The aerosol-forming substrate may comprise between 50% and 85% by weight aerosol-former, between 50% and 80% by weight aerosol-former or between 50% and 75% by weight aerosol-former.

[0074] The aerosol-forming substrate may comprise between 60% and 85% by weight aerosol-former, between 60% and 80% by weight aerosol-former or between 60% and 75% by weight aerosol-former.

[0075] The aerosol-forming substrate may comprise between 70% and 85% by weight aerosol-former, between 70% and 80% by weight aerosol-former or between 70% and 75% by weight aerosol-former.

[0076] The aerosol-forming substrate may comprise nicotine.The aerosol-forming material may comprise natural nicotine, or synthetic nicotine, or a combination of natural and synthetic nicotine.

[0077] The aerosol-forming substrate may comprise at least 0.5% by weight nicotine, at least 1% by weight nicotine, at least 1.5% by weight nicotine or at least 2% by weight nicotine. That is, the aerosol-forming substrate may have a nicotine content of at least 0.5% by weight, at least 1% by weight, at least 1.5% by weight or at least 2% by weight.

[0078] The aerosol-forming matrix may comprise one or more flavoring agents. The one or more flavoring agents may comprise one or more of the following: 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 herbal materials. Suitable herbal materials include herb leaves or other herbal materials from herbal plants, including but not limited to mint (such as peppermint and spearmint), lemongrass (lemon balm), basil, cinnamon, lemon basil, chives, coriander, lavender, sage, tea, thyme, and caraway. The one or more flavoring agents may comprise tobacco materials.

[0079] The aerosol-forming substrate may have a moisture content of about 5% to 25%, preferably about 7% to 15%, in the final product state. For example, the aerosol-forming substrate may be a homogenised tobacco material having a moisture content of about 5% to 25%, preferably about 7% to 15%, in the final product state.

[0080] The aerosol-forming substrate may comprise tobacco leaves; for example, about 15% to 45%, preferably about 20% to 35%, of a tobacco leaf blend comprising at least one of the following tobacco types: flue-cured tobacco; sun-cured tobacco; oriental tobacco. The tobacco material, such as tobacco leaves, is preferably ground and graded to a particle size of about 100 to 380 mesh, preferably about 170 to 320 mesh.

[0081] "Tobacco type" means one of different varieties of tobacco, based, for example, on the different curing processes that the tobacco undergoes before being further processed into tobacco products.

[0082] Examples of flue-cured tobacco are Brazilian flue-cured tobacco, Indian flue-cured tobacco, Chinese flue-cured tobacco, American flue-cured tobacco (such as Virginia tobacco), and flue-cured tobacco from Tanzania.

[0083] Examples of oriental tobaccos are Turkish Oriental, Greek Oriental, Semi-Oriental tobaccos, but also fire-cured American White Burley, such as Perique and Rustica.

[0084] Examples of sun-cured tobacco are dark-cured Brazilian Galpao, Malawi White Burley or other African White Burley, sun-cured or air-cured Indonesian Kasturi.

[0085] The aerosol-forming substrate may comprise cellulose fibers. For example, the aerosol-forming substrate may comprise about 1% to 15% cellulose fibers, preferably about 3% to 7% cellulose fibers. Preferably, the cellulose fibers may have a length of about 10 to 250 μm, preferably about 10 to 120 μm.

[0086] The aerosol-forming matrix may comprise organic fibers, such as non-tobacco fibers or tobacco fibers. For example, the aerosol-forming matrix may comprise approximately 5% to 20%, preferably approximately 7% to 15%, tobacco fibers. Tobacco fibers are preferably derived from stems and / or stalks, which are graded into fibers having a length of approximately 10 to 350 μm, preferably approximately 10 to 180 μm. The aerosol-forming matrix may comprise approximately 10% to 30%, preferably approximately 15% to 25%, of non-tobacco organic fibers. For example, organic fibers may be derived from cellulose, cotton, wood, tea plant varieties that are by-products and by-processing waste of the tea industry. The organic fibers preferably have a length of approximately 10 to 400 μm, preferably approximately 10 to 200 μm.

[0087] The aerosol-forming substrate may comprise a binder. For example, the aerosol-forming substrate may comprise from about 1% to 10%, preferably from about 1% to 5%, of a binder, such as any of the common gums or pectins used in the food and beverage (F&B) industry. Preferred binders may be natural pectins (such as fruit, e.g., citrus) or tobacco pectins; guar gum, locust bean gum, such as hydroxyethyl and / or hydroxypropyl derivatives of these; starches, such as modified or derivatized starches; alginates; methyl, ethyl, ethylhydroxymethyl, and carboxymethyl cellulose; dextran; and xanthan gum. A preferred binder is guar gum.

[0088] The aerosol-forming base may comprise an organic vegetable glycerin agent. For example, the aerosol-forming base may comprise about 15% to 55%, preferably about 20% to 35%, of plant materials such as cloves, echinacea, cumin, ginger, hawthorn berries, elderberries, horse mint, mullein leaves, nettles, plantain, turmeric, yarrow, and compounds of these.

[0089] The aerosol-forming substrate may comprise an organic plant extract. For example, the aerosol-forming substrate may comprise about 1% to 15%, preferably about 2% to 7%, of any of the previously mentioned plant materials, as well as menthol (dl-menthol, C10H200, 2-isopropyl-5-methylcyclohexanol) and p-menthan-3-ol, which is any secondary alcohol such as a diastereoisomer of 5-methyl-2-(propan-2-yl)cyclohexan-1-ol, such as obtained from Chaerophyllum macrospermum, Mesosphaerum sidifolium or other related plant species.

[0090] The aerosol-forming substrate may comprise a plant essential oil, for example about 0.5% to 5%, preferably about 1% to 3% of a plant essential oil, for example such as palm oil, coconut oil and wood-based oil.

[0091] The aerosol-forming substrate preferably comprises an aerosol former, for example about 5% to 35%, preferably about 10% to 25% of an aerosol former. Suitable aerosol formers known in the art include: glycerol; monohydric alcohols such as 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 dimethyl esters of these.

[0092] As used herein, the term "aerosol-generating article" may refer to an article that is capable of generating or releasing an aerosol.

[0093] As used herein, the term "aerosol-forming substrate" may refer to a substrate capable of releasing an aerosol or volatile compounds that can form an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. The aerosol-forming substrate may comprise an aerosol-forming material. The aerosol-forming substrate may be adsorbed, coated, impregnated or otherwise loaded onto a carrier or support. The aerosol-forming substrate may suitably be part of an aerosol-generating article or smoking article.

[0094] 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.

[0095] As used herein, the term "aerosol generating system" refers to the combination of an aerosol generating device and one or more aerosol-forming articles for use with the device. An aerosol generating system may include additional components, such as a charging unit for recharging an onboard power supply in an electrically operated or electric aerosol generating device.

[0096] As used herein, the term "aerosol former" may refer to any suitable known compound or mixture of compounds that promotes the formation of an aerosol in use. 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.

[0097] As used herein with reference to the present invention, the term "nicotine" is used to describe nicotine, nicotine base, or nicotine salts.

[0098] As used herein with reference to the present invention, the terms "proximal", "distal", "upstream" and "downstream" are used to describe the relative positions of components or component parts of an aerosol-generating article.

[0099] As used herein, the term "longitudinal" refers to a 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.

[0100] As used herein, the term "sheet" refers to a laminar element whose width and length are significantly greater than its thickness. The width of the sheet may be greater than 10 mm, preferably greater than 20 mm or 30 mm. In certain embodiments, a sheet of material used to form an aerosol-forming substrate as described herein may have a thickness between 10 micrometers and about 1000 micrometers, for example, between 10 micrometers and about 300 micrometers.

[0101] As used herein, term " homogenized tobacco material " contains any tobacco material formed by the agglomeration of the particle of tobacco material.Homogenized tobacco material sheet or web are formed by making particle tobacco agglomerate, and this particle tobacco is by one or both grinding or otherwise powdering and obtains in tobacco leaf blade and the tobacco stem.In addition, homogenized tobacco material can comprise one or more in tobacco dust, tobacco fines and other particle tobacco by-products that form during the processing, operation and transportation of tobacco.Homogenized tobacco material sheet can be produced by casting, extruding, papermaking process or other any suitable technology known in the art.

[0102] The term "cast leaf" is used herein to refer to a product manufactured by a casting process, which is based on a slurry comprising plant particles (e.g., a mixture of clove particles or tobacco particles and clove particles) and a binder (e.g., guar gum) being cast onto a support surface (such as a belt conveyor), drying the slurry and removing the dried sheet from the support surface. The example of casting or cast leaf process is described in US-A-5,724,998, for example, for the manufacture of cast leaf tobacco. In the cast leaf process, granular plant material is produced by pulverizing, grinding or grinding the part of the plant. The particles produced by one or more plants are mixed with a liquid component (typically water) to form a slurry. Other components in the slurry can include fiber, binder and aerosol forming agent. Granular plant material can be agglomerated in the presence of a binder. The slurry is cast onto a support surface and dried into a homogenized plant material sheet. Preferably, the homogenized plant material for the products according to the present invention can be produced by casting. This type of homogenized plant material can include agglomerated granular plant material.

[0103] As used herein, resistance to draw is expressed in pressure units "mmH2O" or "mmWG" or "mm water column" and may be measured according to ISO 6565:2002.

[0104] The invention is defined in the claims. However, a non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples may be combined with any one or more features of another example, embodiment or aspect described herein.

[0105] Ex1. An aerosol-generating article comprising an aerosol-forming material for generating an aerosol, the aerosol-generating article comprising a first planar layer extending in a first plane and a second planar layer extending in a second plane, the second plane being parallel to the first plane and spaced apart from the first plane, the thickness of the article extending in a direction perpendicular to the first plane and the second plane, wherein a cavity is defined between the first planar layer and the second planar layer, the height of the cavity is defined by the distance between the lower surface of the first planar layer and the upper surface of the second planar layer, and wherein the thickness of the aerosol-generating article is less than 5 mm, and the height of the cavity is greater than 50% of the thickness of the article.

[0106] Ex2. An aerosol-generating article according to example Ex1, wherein the thickness of the aerosol-generating article is defined by the distance between the upper surface of the aerosol-generating article and the lower surface of the aerosol-generating article, for example, between the upper surface of the first planar layer and the lower surface of the second planar layer.

[0107] Ex3. An aerosol-generating article according to Ex1 or Ex2, wherein the thickness of the aerosol-generating article is defined by the distance between the upper surface of the first planar layer and the lower surface of the second planar layer.

[0108] Ex4. An aerosol-generating article according to any of the preceding examples, wherein the aerosol-generating article is defined by an article length extending in the x-direction, an article width extending in the y-direction, and an article thickness extending in the z-direction, wherein an airflow path is defined through the aerosol-forming article between an airflow inlet and an airflow outlet, and the airflow path flows through the cavity.

[0109] Ex5. An aerosol-generating article according to Ex4, wherein the airflow inlet is defined by an inlet width and an inlet height, wherein the inlet width is greater than 80% of the width of the article and the inlet height is greater than 25% of the height of the article, optionally wherein the airflow inlet is substantially rectangular.

[0110] Ex6. An aerosol-generating article according to any of the preceding examples, wherein the height of the cavity is greater than 60% of the thickness of the article, for example greater than 70% of the thickness of the article, for example greater than 80% of the thickness of the article, preferably greater than 85% of the thickness of the article, or greater than 90% of the thickness of the article, for example greater than 95% of the thickness of the article.

[0111] Ex7. An aerosol-generating article according to any of the preceding examples, wherein the article has a thickness between 0.5 mm and 5 mm, for example between 1 mm and 4.75 mm, for example between 1.5 mm and 4.5 mm, for example between 2 mm and 4 mm, for example about 2.5 mm, or about 2.75 mm, or about 3 mm.

[0112] Ex8. An aerosol-generating article according to any of the preceding examples, wherein the height of the cavity is between 0.25 mm and 4.9 mm, for example, between 0.375 mm and 4.5 mm, for example, between 0.5 mm and 4 mm, for example, between 0.625 mm and 3.5 mm, for example, about 2 mm, or about 2.5 mm, or about 2.9 mm.

[0113] Ex9. An aerosol-generating article according to any preceding example, wherein the first planar layer and / or the second planar layer comprises the aerosol-forming material, for example wherein the first planar layer and / or the second planar layer comprises a homogenized tobacco sheet.

[0114] Ex10. An aerosol-generating article according to any preceding example, wherein the first planar layer and / or the second planar layer comprises: an aerosol-forming layer comprising an aerosol-forming material, and at least one further layer, such as an outer layer or a wrapper layer.

[0115] Ex11. An aerosol-generating article according to any of the preceding examples, wherein the thickness of the first layer and / or the second layer is between 150 μm and 1000 μm, for example, between 250 μm and 800 μm, for example, between 300 μm and 600 μm, for example, between 350 μm and 500 μm, for example, about 200 μm, or about 250 μm, or about 300 μm, or about 350 μm, or about 400 μm.

[0116] Ex12. An aerosol-generating article according to any preceding example, wherein the article has a width between 5 mm and 20 mm, for example between 6 mm and 15 mm, for example between 7.5 mm and 13 mm, for example between 9 mm and 12.5 mm, for example about 9.5 mm, or 10 mm, or 11 mm, or 12 mm.

[0117] Ex13. An aerosol-generating article according to Ex12, wherein the cavity has a width between 4.75 mm and 19.75 mm, for example between 5.75 mm and 14.75 mm, for example between 7.25 mm and 12.75 mm, for example between 8.75 mm and 12.25 mm, for example about 9.25 mm, or 9.5 mm, or 10.5 mm, or 11.5 mm.

[0118] Ex14. An aerosol-generating article according to any preceding example, wherein the article has a length between 10 mm and 100 mm, for example between 15 mm and 55 mm, for example between 20 mm and 45 mm, for example between 25 mm and 35 mm, for example about 25 mm, or 28 mm, or 30 mm, or 32 mm.

[0119] Ex15. An aerosol-generating article according to any preceding example, wherein an airflow inlet is defined at a distal end of the article, the airflow inlet being configured to allow air to flow into the cavity.

[0120] Ex16. The aerosol-generating article according to any preceding example, wherein the article further defines a mouthpiece in fluid communication with the cavity, such as an integral mouthpiece or a removable mouthpiece.

[0121] Ex17. An aerosol-generating article according to any of the preceding examples, wherein an airflow path is defined as passing through the aerosol-generating article from an air inlet through the cavity and to an air outlet, wherein the resistance to draw (RTD) of the article along the airflow path between the air inlet and the air outlet is less than 20 mm H2O.

[0122] Ex18. An aerosol-generating article according to any preceding example, wherein the aerosol-forming material is located within the cavity.

[0123] Ex19. An aerosol-generating article according to any preceding example, wherein an airflow path is defined through the aerosol-generating article between a distal end and a proximal end of the aerosol-generating article.

[0124] Ex20. The aerosol-generating article according to any preceding example, further comprising an intermediate layer disposed between the first planar layer and the second planar layer.

[0125] Ex21. An aerosol-generating article according to any preceding example, wherein the plurality of longitudinally extending passages are defined by corrugations of the corrugated element located within the cavity.

[0126] Ex22. An aerosol-generating article according to Ex21, wherein the longitudinally extending passage extends in the x / y plane between the distal end and the proximal end of the article.

[0127] Ex23. An aerosol-generating article according to any of the preceding examples, further comprising a planar frame positioned between the first planar layer and the second planar layer, preferably wherein the cavity is defined by a lower surface of the first layer, an upper surface of the second layer and an inner wall of the planar frame.

[0128] Examples will now be further described with reference to the accompanying drawings, in which:

[0129] Figure 1 is a perspective side view of an aerosol-generating article according to a first embodiment of the present disclosure;

[0130] Figure 2a is a perspective side view of an aerosol-generating article according to a second embodiment of the present disclosure;

[0131] Figure 2b yes Figure 2a a schematic side cross-sectional view of an aerosol-generating article;

[0132] Figure 3a is a perspective side view of an aerosol-generating article according to a third embodiment of the present disclosure;

[0133] Figure 3b is an alternative perspective side view of an aerosol-generating article according to a third embodiment of the present disclosure;

[0134] Figure 4 is a schematic end view of an aerosol-generating article according to a fourth embodiment of the present disclosure;

[0135] Figure 5 yes Figure 4 a schematic side view of an aerosol-generating article;

[0136] Figure 6 yes Figure 4 A schematic plan view of an aerosol-generating article;

[0137] Figure 7 Shown as Figure 4 Schematic diagram of a corrugated element used in an aerosol-generating article;

[0138] Figure 8 shows a perspective view of an aerosol-generating article according to a fifth embodiment of the present disclosure;

[0139] Figure 9 Shown Figure 8 an exploded perspective view of an aerosol-generating article;

[0140] Figure 10 Shown Figure 8 Another exploded perspective view of an aerosol-generating article;

[0141] Figure 11 Shown Figure 8 A schematic transverse cross-sectional view of an aerosol-generating article;

[0142] Figure 12 Shown Figure 8 A schematic longitudinal cross-sectional view of an aerosol-generating article;

[0143] Figure 13 shows an exploded perspective view of an aerosol-generating article according to a sixth embodiment of the present disclosure;

[0144] Figure 14 Shown Figure 13 A schematic transverse cross-sectional view of an aerosol-generating article;

[0145] Figure 15 Shown Figure 13 Schematic side cross-sectional view of an aerosol-generating article.

[0146] Figure 1A perspective side view of an aerosol-generating article 100 according to a first embodiment of the present disclosure is shown. The aerosol-generating article 100 has a first planar layer 110 extending in a first plane and a second planar layer 120 extending in a second plane, the second plane being parallel to and spaced apart from the first plane. The thickness of the aerosol-generating article 100 extends in a z-dimension along a direction perpendicular to the first and second planes. The aerosol-generating article 100 comprises an aerosol-forming substrate. In one embodiment, the aerosol-generating article 100 may consist essentially of the aerosol-forming substrate. In another embodiment, the aerosol-forming substrate may be one of a plurality of component parts of the aerosol-generating article 100. The aerosol-forming substrate may be enclosed within the interior of the aerosol-generating article 100. The aerosol-forming substrate may at least partially define the exterior of the aerosol-generating article 100; for example, one or both of the first planar layer 110 and the second planar layer 120 may comprise or consist of the aerosol-forming substrate.

[0147] A suitable aerosol-forming substrate may be homogenised tobacco.

[0148] The aerosol-generating article 100 has a length extending in the x-dimension of 80 mm, a width extending in the y-dimension of 15 mm, and a height extending in the z-dimension of 3.6 mm (which may also be referred to as thickness). The thickness of the aerosol-generating article is defined by the distance between the upper surface of the aerosol-generating article (which is the upper surface of the first planar layer 110 in this example) and the lower surface of the aerosol-generating article (which is the lower surface of the second planar layer 120 in this example).

[0149] The aerosol-generating article 100 comprises a cavity ( Figure 1 (not shown) A cavity is defined between first planar layer 110 and second planar layer 120. The cavity height is defined by the distance between the lower surface of first planar layer 110 and the upper surface of second planar layer 120. The cavity height is greater than 50% of the thickness of the article. The cavity height is greater than 1.8 mm, for example, approximately 2.5 mm. The cavity width is approximately 12 mm.

[0150] The aerosol-forming article comprises an aerosol-forming material. In this embodiment, the first planar layer 110 and the second planar layer 120 each comprise a homogenized tobacco sheet and an outer layer. The outer layer of the first planar layer 110 forms the upper surface of the first planar layer 110, and the outer layer of the second planar layer 120 forms the lower surface of the second planar layer 120. Each outer layer comprises a paper sheet.

[0151] Figure 2aA perspective side view of an aerosol-generating article 200 according to a second embodiment of the present disclosure is shown, which is a variation of the aerosol-generating article 100. Features common to the aerosol-generating article 100 are referred to using the same reference numerals. An airflow path 230 is defined through the aerosol-generating article 200 between the upper planar layer 110 and the lower planar layer 120. The airflow path 230 extends between opposing first and second ends 201, 202 of the aerosol-generating article 200. The first end 201 can define a distal end of the aerosol-generating article 200, and the second end 202 can define a proximal end of the aerosol-generating article. The airflow path 230 can be directed toward the mouth of a user to allow the user to inhale an aerosol generated by heating the aerosol-forming substrate of the aerosol-generating article 200.

[0152] An air flow passage is defined through the aerosol-forming article 200 between an air flow inlet 240 and an air flow outlet (not shown in FIG2 ). The air flow passage extends through the cavity and is configured to, in use, allow air to flow from the air inlet 240, through the cavity, and out of the air outlet 260. The air flow inlet 240 is defined by an inlet width and an inlet height, wherein the inlet width is greater than 80% of the width of the aerosol-generating article 200 and the inlet height is greater than 25% of the height of the aerosol-generating article 200.

[0153] An air flow path is defined through the aerosol-generating article 200 from the air inlet 240 , through the cavity, and to the air outlet, wherein the resistance to draw (RTD) of the aerosol-generating article 200 along the air flow path between the air inlet 240 and the air outlet 260 is less than 20 mm H 2 O.

[0154] Figure 2b Shown Figure 2a Schematic side cross-sectional view of an aerosol-generating article. Figure 2b An internal cross-section of an aerosol-generating article is shown. In use, when a user draws on the air outlet 260, air is drawn into the aerosol-generating article through the airflow inlet 240 and along the airflow path. The air flows through the cavity 270 to the airflow outlet 260.

[0155] The aerosol-forming material 280 is positioned on either side of the cavity 270. Alternatively, the aerosol-forming material may be located within the cavity 270. In use, when the aerosol-generating article is heated by an external heater, the aerosol-forming material 280 in the aerosol-generating article 200 is heated and the aerosol former is vaporized. When a user draws on the air outlet 260, the vapor is entrained in the airflow in the airflow path. The vapor cools in the airflow and condenses to form an aerosol, which can then be inhaled by the user.

[0156] Figure 3aShown is a perspective side view of an aerosol-generating article 290 according to a third embodiment of the present disclosure, which is a variation of the aerosol-generating articles 100 , 200 . Figure 3b There is shown an alternative perspective side view of an aerosol-generating article 290. Features in common with aerosol-generating articles 100 and 200 are referred to using the same reference numerals.

[0157] The aerosol generating article 290 includes a mouthpiece 250. The mouthpiece 250 is in fluid communication with the cavity. Figure 3b As shown in , the mouthpiece 250 includes an air outlet 360. In this embodiment, the mouthpiece 250 is integral. However, in other examples, the mouthpiece may be removable.

[0158] Figure 4 、 5 6 show an end view, a side view, and a plan view, respectively, of an aerosol-generating article 300 according to a fourth embodiment of the present disclosure. The aerosol-generating article 300 includes a first planar layer (upper layer) 310 extending in a first plane, and a second planar layer (lower layer) 320 extending in a second plane parallel to and spaced apart from the first plane. The aerosol-generating article 300 also includes an intermediate or separating layer 340 disposed between the upper layer 310 and the lower layer 320. The thickness of the article 300 extends in a z-direction perpendicular to the first and second planes.

[0159] The planar upper layer 310 is formed of a paper sheet having a thickness of 300 microns. The planar lower layer 320 is formed of a paper sheet having a thickness of 300 microns. A cavity is defined between the upper layer 310 and the lower layer 320, and the height of the cavity is defined by the distance between the lower surface of the upper layer 310 and the upper surface of the lower layer 320.

[0160] The middle layer 340 is located within the cavity. The middle layer 340 is a corrugated element formed from a corrugated sheet of aerosol-forming material 345. A suitable aerosol-forming material may be homogenized tobacco. Thus, the middle layer 340 may be formed from a corrugated sheet of homogenized tobacco material 345.

[0161] Figure 7 Shown is a corrugated sheet of aerosol-forming material 345. The corrugations have an amplitude 346 of 3 mm and a wavelength 347 of 3 mm. The sheet of aerosol-forming material 345 forming the intermediate layer 340 has a thickness of 150 microns.

[0162] The intersections 351 , 352 between the upper layer 310 and the middle layer 340 and between the lower layer 320 and the middle layer 340 include an adhesive joining the respective layers.

[0163] The aerosol-generating article 300 has a length extending in the x-dimension of 80 mm, a width extending in the y-dimension of 15 mm and a thickness extending in the z-dimension of 3.6 mm. The height of the cavity is greater than 50% of the thickness of the aerosol-generating article 300.

[0164] The corrugations of the middle layer 340 form a first set of longitudinally extending channels 361 defined by the upper layer 310 and the middle layer 340, and a second set of longitudinally extending channels 362 defined by the lower layer 320 and the middle layer 340. The first set of longitudinally extending channels 361 and the second set of longitudinally extending channels 362 extend through the length of the middle layer 340 between a proximal end 371 of the aerosol-generating article 300 and a distal end 372 of the aerosol-generating article 300. The longitudinally extending channels 361, 362 extend between the distal end 372 and the proximal end 371 of the aerosol-generating article 300 in the x / y plane.

[0165] The longitudinally extending channels 361, 362 define an airflow passage through the aerosol-forming article between the airflow inlet and the airflow outlet. The airflow passage extends through the cavity so that, in use, air flows through the cavity. The longitudinally extending channels 361, 362 define an airflow path through the aerosol-forming material 345. Thus, the airflow path passes over both sides of the sheet of aerosol-forming material 345. The porosity of the aerosol-generating article along the airflow path is approximately 90%. This provides an extremely low resistance to draw (RTD) of less than 5 mm H2O. In fact, the RTD is close to zero.

[0166] The aerosol-forming material 345 may be a sheet of any suitable aerosol-forming material.

[0167] During use of the aerosol-generating article 300, the aerosol-forming material 345 is heated so that the aerosol-forming material 345 releases volatile compounds, which are then entrained in air drawn into the passages 361, 362 via the distal end 372. The volatile compounds then cool and condense to form an aerosol, which can be drawn out of the passages 361, 362 of the aerosol-generating article 300 via the proximal end 371.

[0168] Figure 8 An aerosol-generating article 400 according to a fifth embodiment of the present disclosure is shown. The aerosol-generating article 400 includes a first planar outer layer 424 forming an upper planar outer surface 421, a second planar outer layer 425 forming a lower planar outer surface 422, and a frame 450 positioned between the first planar outer layer 424 and the second planar outer layer 425. The lower planar outer surface 422 is positioned parallel to the lower planar outer surface 421. The thickness of the aerosol-generating article is defined by the upper surface 421 of the first planar outer layer 424 and the lower surface 422 of the second planar outer layer 425.

[0169] Figure 9 and 10 Shown Figure 8 Exploded view of the aerosol-generating article 400 of FIG. The frame 450 defines and at least partially defines the cavity 430. Figure 9 The cavity 430 is shown in an empty state. Figure 10 The cavity 430 is shown filled with an aerosol-forming substrate 440 . Figure 11 and 12 Respective transverse and longitudinal cross-sectional views of the aerosol-generating article 400 are shown when the cavity 430 is filled with the aerosol-forming substrate 440 .

[0170] First and second planar outer layers 424, 425 are made of 35-micron-thick cigarette paper and are in physical contact with and bonded to frame 450. First planar outer layer 424 overlies a first end of cavity 430 and forms a first cavity end wall 431. Second planar outer layer 425 overlies a second end of cavity 430 and forms a second cavity end wall 432, which is opposite first cavity end wall 431. In other words, frame 450, first and second planar outer layers 424, 425 collectively define cavity 430.

[0171] The frame 450 has a hollow rectangular parallelepiped shape and is made of cardboard. The frame 450 defines an orifice that extends through the height (also referred to as the thickness) of the frame 450, and the orifice at least partially forms the cavity 430 of the aerosol-generating article 400. The frame 450 includes a peripheral wall 451 that defines the cavity 430. The peripheral wall 451 includes a front wall 413 and a rear 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 451 at least partially defines the perimeter of the cavity 430. The outer transverse surface 453 of the peripheral wall 451 at least partially defines the perimeter of the aerosol-generating article 400. The peripheral wall 451 has a radial thickness measured between the inner transverse surface 452 of the frame 450 and the outer transverse surface 453 of the frame 450 of approximately 5 mm.

[0172] The air inlet 411 and the 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 rear wall 414. An air flow path extends through the cavity 430 between the air inlet 411 and the air outlet 412. The air flow inlet 411 is configured to allow air to flow into the cavity, and the air flow outlet 412 is configured to allow air to flow out of the cavity. Figures 10 to 12As shown in FIG, an aerosol-forming substrate 440 is positioned within the cavity 430. The aerosol-forming substrate 440 comprises an aerosol-generating material in the form of tobacco cut filler and has an aerosol-forming agent content of 5 wt% on a dry weight basis. As shown, the aerosol-forming substrate 440 fills the entire volume of the cavity 430.

[0173] The aerosol-generating article 400 has a rectangular parallelepiped shape and has a height (or thickness) extending in the z dimension of 4 mm (as measured between the first planar outer surface 421 and the second planar outer surface 422), a width extending in the y dimension of 10 mm, and a length extending in the x dimension of 60 mm. The frame 450 has a height (or thickness) extending in the z dimension of 3.93 mm, a width extending in the y dimension of 10 mm, and a length extending in the x dimension of 60 mm. The cavity 430 has a height (or thickness) extending in the z dimension that is greater than 50% of the thickness of the aerosol-generating article 400. In this example, the cavity has a thickness of 3.93 mm, a width extending in the y dimension of 9.93 mm, and a length extending in the x dimension of 52 mm.

[0174] The air inlet 411 is defined by an inlet width and an inlet height, wherein the inlet width is greater than 80% of the width of the aerosol-generating article and the inlet height is greater than 25% of the height of the aerosol-generating article. In this example, the air flow inlet is substantially rectangular and has an inlet width of 9 mm and an inlet height of 1.2 mm. Figure 13 An aerosol-generating article 500 according to a sixth embodiment of the present disclosure is shown. Features common to aerosol-generating article 400 are designated by the same reference numerals. Aerosol-generating article 500 differs from aerosol-generating article 400 in that the aerosol-forming substrate is in the form of a sheet 540 of aerosol-generating material, in particular a sheet of corrugated homogenised tobacco material. Figure 14 and 15 Shown Figure 13 Corresponding transverse and side cross-sectional views of the aerosol-generating article 500.

[0175] The corrugated homogenised tobacco material sheet 540 comprises a plurality of parallel corrugations having a plurality of substantially parallel peaks 543 and valleys 544. Figure 13 As can be seen in FIG, a plurality of parallel corrugations are defined by a corrugation profile, which is sinusoidal. The plurality of parallel corrugations have a corrugation wavelength of approximately 4.6 mm. As indicated by peaks 543 and valleys 544 coinciding with first and second cavity end walls 431, 432, respectively, the corrugation amplitude is approximately the same as the height (or thickness) of cavity 430.

[0176] The plurality of parallel corrugations form a plurality of channels 545 between the sheet of aerosol-generating material 540 and the first chamber end wall 431, and a plurality of channels 546 between the sheet of aerosol-generating material 540 and the second chamber end wall 432. The plurality of channels 545, 546 extend in the longitudinal direction of the aerosol-generating article 500 and form at least a portion of an airflow passage extending between the air inlet 411 and the air outlet 412.

[0177] During use of each of the aerosol-generating articles 400, 500, the aerosol-forming substrate 440, 540 is heated to cause the aerosol-forming substrate 440, 540 to release volatile compounds, which are then entrained in air drawn into the cavity 430 through the air inlet 411. The volatile compounds then cool and condense to form an aerosol, which can be drawn out of the aerosol-generating article 400, 500 through the air outlet 412.

[0178] For exemplary purposes applicable to any of the above embodiments, the composition of a suitable aerosol-forming substrate may be as follows. Percentages are given as weight percentages relative to the product in its final state. The aerosol-forming substrate may have a moisture content of about 5% to 25%, preferably about 7% to 15%, in the final product state. The aerosol-forming substrate may further comprise the following:

[0179] 1. Tobacco leaf; for example, about 15% to 45%, preferably about 20% to 35%, of a tobacco leaf blend comprising at least one of the following tobacco types: flue-cured tobacco; sun-cured tobacco; or oriental tobacco. The tobacco material is ground and graded to a particle size of about 100 to 380 mesh, preferably about 170 to 320 mesh.

[0180] 2. Cellulose fibers; for example, about 1% to 15%, preferably about 3% to 7%, of cellulose fibers having a length of about 10 to 250 μm, preferably about 10 to 120 μm.

[0181] 3. Tobacco fibers; for example, about 5% to 20%, preferably about 7% to 15%, of any tobacco type or blend of tobacco types, as a filler. The tobacco fibers are preferably derived from stems and / or stalks, which are fractionated into fibers having a length of about 10 to 350 μm, preferably about 10 to 180 μm.

[0182] 4. Binder; for example, about 1% to 10%, preferably about 1% to 5%, of a binder, such as any of the common gums or pectins used in the food and beverage (F&B) industry. Preferred binders may be natural pectins (such as fruit, e.g., citrus) or tobacco pectins; guar gum, locust bean gum, such as hydroxyethyl and / or hydroxypropyl derivatives of these; starches, such as modified or derivatized starches; alginates; methyl, ethyl, ethylhydroxymethyl, and carboxymethyl cellulose; dextran; and xanthan gum. A preferred binder is guar gum.

[0183] 5. Aerosol formers; for example, about 5% to 35%, preferably about 10% to 25% aerosol formers. Suitable aerosol formers known in the art include: glycerol; monohydric alcohols such as 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 dimethyl esters of these.

[0184] "Tobacco type" means one of different varieties of tobacco, based, for example, on the different curing processes that the tobacco undergoes before being further processed into tobacco products.

[0185] For illustrative purposes, the composition of yet another aerosol-forming substrate (which may also be suitable for use as an aerosol-forming substrate in any of the above embodiments) is described below. Percentages are given as weight percentages relative to the product in its final state. The aerosol-forming substrate may comprise:

[0186] 1. An aerosol former, such as glycerol; e.g. about 10% to 40%, preferably about 20% to 30%.

[0187] 2. Organic fibers; for example, about 10% to 30%, preferably about 15% to 25%, of any plant species suitable and of a purity meeting applicable FDA F&B grade requirements, as commonly available in the market. For example, the organic fibers can be derived from cellulose, cotton, wood, or tea plant species that are byproducts and secondary processing waste from the F&B tea industry. The organic fibers preferably have a length of about 10 to 400 μm, preferably about 10 to 200 μm.

[0188] 3. Organic vegetable glycerin; for example, about 15% to 55%, preferably about 20% to 35% of plant materials such as cloves, echinacea, cumin, ginger, hawthorn berries, elderberries, horse mint, mullein leaves, nettle, plantain, turmeric, yarrow, and compounds of these.

[0189] 4. Organic plant extracts; for example, about 1% to 15%, preferably about 2% to 7%, of any of the previously mentioned plant materials, as well as menthol (dl-menthol, C10H200, 2-isopropyl-5-methylcyclohexanol) and p-menthan-3-ol, which is any secondary alcohol such as a diastereomer of 5-methyl-2-(propan-2-yl)cyclohexan-1-ol, such as obtained from Chaerophyllum macrospermum, Mesosphaerum sidifolium or other related plant species.

[0190] Alternatively, such an aerosol-forming substrate may also contain about 0.5% to 5%, preferably about 1% to 3%, of plant essential oils, such as palm oil, coconut oil and wood-based essential oils.

[0191] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers representing amounts, quantities, percentages, etc. should be understood to be modified by the term "about" in all cases. Moreover, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein that may be specifically listed or may not be listed herein. Therefore, in this context, the number "A" is understood to be "A" ± 10% of "A". In this article, the number "A" can be considered to be a numerical value within the general standard error of measurement of the property modified by the number "A". In certain cases used in the appended claims, the number "A" may deviate from the percentages listed above, provided that the amount of "A" deviation does not substantially affect the basic characteristics and novel features of the invention claimed. Moreover, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein that may be specifically listed or may not be listed herein. The terms "in which" and "wherein" are used synonymously in this specification.

Claims

1. An aerosol-generating article comprising an aerosol-forming material for generating an aerosol, the aerosol-generating article comprising a first planar layer extending in a first plane and a second planar layer extending in a second plane, the second plane being parallel to the first plane and spaced apart from the first plane, the thickness of the aerosol-generating article extending in a direction perpendicular to the first plane and the second plane, wherein a cavity is defined between the first planar layer and the second planar layer, the height of the cavity being defined by the distance between the lower surface of the first planar layer and the upper surface of the second planar layer, and wherein the thickness of the aerosol-generating article is less than 5 mm and the height of the cavity is greater than 50% of the thickness of the article.

2. An aerosol-generating article according to claim 1, wherein the thickness of the aerosol-generating article is defined by the distance between the upper surface of the aerosol-generating article and the lower surface of the aerosol-generating article, for example, between the upper surface of the first planar layer and the lower surface of the second planar layer.

3. An aerosol-generating article according to claim 1 or 2, wherein the aerosol-generating article is defined by an article length extending in the x-direction, an article width extending in the y-direction and an article thickness extending in the z-direction, wherein an airflow path is defined through the aerosol-forming article between an airflow inlet and an airflow outlet, and the airflow path extends through the cavity.

4. An aerosol-generating article according to claim 3, wherein the airflow inlet is defined by an inlet width and an inlet height, wherein the inlet width is greater than 80% of the width of the article and the inlet height is greater than 25% of the height of the article, optionally wherein the airflow inlet is substantially rectangular.

5. An aerosol-generating article according to any preceding claim, wherein the height of the cavity is greater than 60% of the thickness of the aerosol-generating article, for example greater than 70% of the thickness of the article, for example greater than 80% of the thickness of the aerosol-generating article, preferably greater than 85% of the thickness of the aerosol-generating article, or greater than 90% of the thickness of the aerosol-generating article, for example greater than 95% of the thickness of the aerosol-generating article.

6. An aerosol-generating article according to any preceding claim, wherein the article has a thickness of between 0.5 mm and 5 mm, such as between 1 mm and 4.75 mm, such as between 1.5 mm and 4.5 mm, such as between 2 mm and 4 mm, such as about 2.5 mm, or about 2.75 mm, or about 3 mm.

7. An aerosol-generating article according to any preceding claim, wherein the height of the cavity is between 0.25 mm and 4.9 mm, for example between 0.375 mm and 4.5 mm, for example between 0.5 mm and 4 mm, for example between 0.625 mm and 3.5 mm, for example about 2 mm, or about 2.5 mm, or about 2.9 mm.

8. An aerosol-generating article according to any preceding claim, wherein the first planar layer, the second planar layer, or both the first planar layer and the second planar layer comprise the aerosol-forming material, for example wherein the first planar layer, the second planar layer, or both the first planar layer and the second planar layer comprise a homogenised tobacco sheet.

9. An aerosol-generating article according to any preceding claim, wherein the first planar layer, the second planar layer, or both the first planar layer and the second planar layer comprise: An aerosol-forming layer comprising an aerosol-forming material, and at least one further layer, such as an outer layer or a wrapper layer.

10. An aerosol-generating article according to any preceding claim, wherein the cavity has a width of between 4.75 mm and 19.75 mm, for example between 5.75 mm and 14.75 mm, for example between 7.25 mm and 12.75 mm, for example between 8.75 mm and 12.25 mm, for example about 9.25 mm, or 9.5 mm, or 10.5 mm, or 11.5 mm.

11. An aerosol-generating article according to any preceding claim, wherein the article has a length of between 10 mm and 100 mm, such as between 15 mm and 55 mm, such as between 20 mm and 45 mm, such as between 25 mm and 35 mm, such as about 25 mm, or 28 mm, or 30 mm, or 32 mm.

12. An aerosol-generating article according to any preceding claim, wherein an airflow path is defined as passing through the aerosol-generating article from the airflow inlet, through the cavity and to the airflow outlet, wherein the airflow inlet is defined at the distal end of the aerosol-generating article, wherein the airflow outlet is defined at the proximal end of the aerosol-generating article, and wherein the resistance to draw (RTD) of the article along the airflow path between the airflow inlet and the airflow outlet is less than 20 mm H2O.

13. An aerosol-generating article according to any preceding claim, wherein at least some of the aerosol-forming material is located within the cavity.

14. An aerosol-generating article according to any preceding claim, wherein a plurality of longitudinally extending channels are defined by corrugations of a corrugated element located within the cavity.

15. An aerosol-generating article according to any preceding claim, further comprising a planar frame positioned between the first planar layer and the second planar layer, preferably wherein the cavity is defined by a lower surface of the first planar layer, an upper surface of the second planar layer and an inner wall of the planar frame.

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