Aerosol-generating article

Abstract

An aerosol-generating article (100) is provided for use with an aerosol-generating device to generate an aerosol. The aerosol-generating article (100) comprises an upper surface (110), a lower surface (120), an aerosol-forming substrate and a first cover (130). The aerosol-generating article (100) is 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 upper and lower surfaces (110, 120) are opposed to and separated from each other in the z direction. The height is less than each of the width and the length. The first cover (130) is arranged to overlie one of the upper surface (110) and the lower surface (120). A flap portion (132, 133) of the first cover (130) is folded to overlie or define a side wall of the aerosol-generating article.

Description

[0001] AEROSOL-GENERATING ARTICLE

[0002] The present disclosure relates to an aerosol-generating article comprising an aerosol-forming substrate.

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

[0004] However, a significant portion of the aerosol-forming substrate in these cylindrical aerosol-generating articles may not be sufficiently heated to form an aerosol during use. This is undesirable since the insufficiently heated portion of the 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 aerosol-forming substrate is heated from the inside or the outside. Moreover, the components of these cylindrical aerosolgenerating articles normally need to have the same or very similar outer diameters so that they can be brought together, accurately positioned in co-axial alignment and wrapped in a cigarette paper. This can lead to increased cost and complexity of manufacture.

[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. It is also an objective of the present disclosure to provide an aerosol-generating article that can be manufactured relatively efficiently and cheaply.

[0006] According to the present disclosure, there may be provided an aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosol-generating article comprising an aerosolforming substrate for producing 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 an upper surface and a lower surface, the upper and lower surfaces opposed to and separated from each other in the z direction. The aerosol-generating article may comprise a first cover, the first cover arranged to overlie one of the upper surface and the lower surface, a flap portion of the first cover folded to overlie or define a side wall of the aerosol-generating article.

[0007] The first cover may be configured to limit, prevent or inhibit the passage of moisture and / or aerosol across the thickness of the first cover. In this manner, the first cover may facilitate preventing excessive moisture absorption by the aerosol-generating article or loss of moisture content from the article, especially via surfaces (for example, side wall(s)) of the aerosol-generating article overlaid by the first cover where such surfaces of the aerosol-generating article have a greater level of permeability than the first cover. Limiting, preventing or inhibiting the passage of moisture into the aerosol-generating article may avoid or limit any reduction in the flexural stiffness of the aerosol-generating article. Similarly, limiting, preventing or inhibiting the passage of moisture into the aerosol-generating article (especially into the aerosol-forming substrate of the article) may avoid the user receiving an unpleasant user experience on heating of the substrate during use of the aerosol-generating article with an aerosol-generating device.

[0008] The first cover may also facilitate limiting, preventing or inhibiting loss of aerosol through the side wall(s) of the article during use of the aerosol-generating article in a usage session, for example a usage session in which the article is used with an aerosol-generating device in order to apply heat to the article to cause volatile compounds to be evolved from the aerosol-forming substrate of the article.

[0009] Preferably, the first cover may be configured to be impermeable to water or air.

[0010] The first cover may have a permeability of between 1 to 10 Coresta units, for example between 1 to 5 Coresta units, for example between 1 to 3 Coresta units.

[0011] A higher level of impermeability of the first cover may limit, prevent or inhibit loss of aerosol from the aerosol-generating article via the side wall(s) of the article during use of the article in a usage session. It may also limit, prevent or inhibit passage of moisture into or out from the aerosol-generating article via the side wall(s) of the article.

[0012] Preferably, the first cover comprises one or a combination of materials selected from a group consisting of parchment paper, supercalendered paper (for example glassine), tracing paper, cellulose films, coated paper (for example PVOH paper), and metal foil. These specified materials may facilitate limiting or preventing the passage of moisture and / or aerosol across the thickness of the first cover.

[0013] The materials of the above-mentioned group are preferably in sheet form.

[0014] The height of the aerosol-generating article is less than both of the length and width of the aerosolgenerating article. For the purpose of the present disclosure, the “height” of the aerosol-generating article may also be referred to as the “thickness” of the aerosol-generating article.

[0015] According to the present disclosure, there may be provided an aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosol-generating article comprising an aerosolforming substrate for producing an aerosol, the aerosol-generating article comprising 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. The aerosol-generating article may further comprise a first cover, the first cover arranged to overlie one of the substantially planar upper surface and the substantially planar lower surface, a flap portion of the first cover folded to overlie or define a side wall of the aerosol-generating article.

[0016] The first cover may be configured to limit, prevent or inhibit the passage of moisture and / or aerosol across the thickness of the first cover. In this manner, the first cover may facilitate preventing excessive moisture absorption by the aerosol-generating article or loss of moisture content from the article, especially via surfaces (for example, side wall(s)) of the aerosol-generating article overlaid by the first cover where such surfaces of the aerosol-generating article have a greater level of permeability than the first cover. Limiting, preventing or inhibiting the passage of moisture into the aerosol-generating article may avoid or limit any reduction in the flexural stiffness of the aerosol-generating article. Similarly, limiting, preventing or inhibiting the passage of moisture into the aerosol-generating article (especially into the aerosol-forming substrate of the article) may avoid the user receiving an unpleasant user experience on heating of the substrate during use of the aerosol-generating article with an aerosol-generating device. The first cover may also facilitate limiting, preventing or inhibiting loss of aerosol through the side wall(s) of the article during use of the aerosol-generating article in a usage session, for example a usage session in which the article is used with an aerosol-generating device in order to apply heat to the article to cause volatile compounds to be evolved from the aerosol-forming substrate of the article.

[0017] Preferably, the first cover may be configured to be impermeable to water or air.

[0018] The first cover may have a permeability of between 1 to 10 Coresta units, for example between 1 to 5 Coresta units, for example between 1 to 3 Coresta units.

[0019] A higher level of impermeability of the first cover may limit, prevent or inhibit loss of aerosol from the aerosol-generating article via the side wall(s) of the article during use of the article in a usage session. It may also limit, prevent or inhibit passage of moisture into or out from the aerosol-generating article via the side wall(s) of the article.

[0020] Preferably, the first cover comprises one or a combination of materials selected from a group consisting of parchment paper, supercalendered paper (for example glassine), tracing paper, cellulose films, coated paper (for example PVOH paper), and metal foil. These specified materials facilitate limiting or preventing the passage of moisture and / or aerosol across the thickness of the wrapper.

[0021] The materials of the above-mentioned group are preferably in sheet form.

[0022] 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. In particular, the height of the aerosol-generating article may be less than 50 percent of both the length and width of the aerosol-generating 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 aerosol-forming 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.

[0023] According to the present disclosure, there may be provided an aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosol-generating article comprising an upper surface, a lower surface and an aerosol-forming substrate. The aerosol-generating article may be 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 upper and lower surfaces may be opposed to and separated from each other in the z direction, wherein the height is less than each of the width and the length. The aerosol-generating article may further comprise a first cover, the first cover arranged to overlie one of the upper surface and the lower surface, a flap portion of the first cover folded to overlie or define a side wall of the aerosol-generating article.

[0024] The first cover may be configured to limit, prevent or inhibit the passage of moisture and / or aerosol across the thickness of the first cover. In this manner, the first cover may facilitate preventing excessive moisture absorption by the aerosol-generating article or loss of moisture content from the article, especially via surfaces (for example, side wall(s)) of the aerosol-generating article overlaid by the first cover where such surfaces of the aerosol-generating article have a greater level of permeability than the first cover. Limiting, preventing or inhibiting the passage of moisture into the aerosol-generating article may avoid or limit any reduction in the flexural stiffness of the aerosol-generating article. Similarly, limiting, preventing or inhibiting the passage of moisture into the aerosol-generating article (especially into the aerosol-forming substrate of the article) may avoid the user receiving an unpleasant user experience on heating of the substrate during use of the aerosol-generating article with an aerosol-generating device.

[0025] The first cover may also facilitate limiting, preventing or inhibiting loss of aerosol through the side wall(s) of the article during use of the aerosol-generating article in a usage session, for example a usage session in which the article is used with an aerosol-generating device in order to apply heat to the article to cause volatile compounds to be evolved from the aerosol-forming substrate of the article.

[0026] Preferably, the first cover may be configured to be impermeable to water or air.

[0027] The first cover may have a permeability of between 1 to 10 Coresta units, for example between 1 to 5 Coresta units, for example between 1 to 3 Coresta units.

[0028] A higher level of impermeability of the first cover may limit, prevent or inhibit loss of aerosol from the aerosol-generating article via the side wall(s) of the article during use of the article in a usage session. It may also limit, prevent or inhibit passage of moisture into or out from the aerosol-generating article via the side wall(s) of the article.

[0029] Preferably, the first cover comprises one or a combination of materials selected from a group consisting of parchment paper, supercalendered paper (for example glassine), tracing paper, cellulose films, coated paper (for example PVOH paper), and metal foil. These specified materials facilitate limiting or preventing the passage of moisture and / or aerosol across the thickness of the first cover.

[0030] The materials of the above-mentioned group are preferably in sheet form

[0031] The flap portion of the first cover may overlie a side wall of the aerosol-generating article, the first cover having a permeability less than the side wall. In this manner, the flap portion of the first cover may function as a barrier to limit, prevent or inhibit the passage of moisture and / or aerosol through the side wall of the aerosol-generating article.

[0032] The flap portion of the first cover may overlie and be bonded to a side wall of the aerosol-generating article, for example by use of an adhesive. The bond between the flap portion and the side wall may enhance the flexural stiffness of the aerosol-generating article as a whole.

[0033] The aerosol-generating article may be free of adhesive at an interface between the first cover and the respective one of the upper surface and the lower surface overlaid by the first cover.

[0034] The aerosol-generating article may preferably comprise a frame disposed between the upper surface and the lower surface. The frame may at least partially define a cavity. The flap portion of the first cover may overlie or define a side wall of the frame.

[0035] The first cover may have a permeability less than that of the frame. In this manner, the flap portion of the first cover may limit, prevent or inhibit the passage of moisture into and through the side wall of the frame, thereby helping to maintain the flexural stiffness of the frame at a desired level. Further, the flap portion may also limit, prevent or inhibit the loss of aerosol from the aerosol-generating article via the side wall of the frame during use of the article in a usage session. The permeability of the first cover may be no more than 20% of the permeability of the frame, for example no more than 15% of the permeability of the frame, for example no more than 10% of the permeability of the frame, for example no more than 5% of the permeability of the frame, for example no more than 2.5% of the permeability of the frame.

[0036] The side wall of the frame may have a thickness defined between an inner periphery and an outer periphery of the side wall of between 0.5 millimetres and 1 .5 millimetres, for example between 0.5 millimetres and 1 .25 millimetres, for example between 0.5 millimetres and 1 millimetre, for example between 0.5 millimetres and 0.8 millimetres.

[0037] Where the flap portion of the first cover overlies and is bonded to the side wall of the frame, the bond between the flap portion and the frame serves to enhance the flexural stiffness of the frame, thereby allowing use of a frame having a reduced side wall thickness.

[0038] The frame may have a height within a range of between 1 .5 mm and 5 mm, for example between 1 .5 millimetres and 4 millimetres, for example between 1 .5 millimetres and 3 millimetres.

[0039] Preferably, at least part of the aerosol-forming substrate may be located within the cavity.

[0040] The frame may comprise a plurality of layers successively arranged over one another along the z- direction. A flap portion of at least one of the layers may be folded to extend along the z-direction to overlie or be overlaid by the flap portion of the first cover. The flap portion of the layer or layers may be bonded to the flap portion of the first cover, thereby enhancing the structural rigidity of the frame. Each of the plurality of layers may be arranged in an x-y plane.

[0041] The flap portion of the first cover may be folded over itself or rolled over itself to define a plurality of layers for the flap portion of the first cover. In this manner, the flap portion of the first cover possesses a greater flexural stiffness than where the flap portion instead defines only a single layer. The plurality of layers of the flap portion of the first cover may be bonded to each other, for example by use of an adhesive.

[0042] The first cover may be formed from one or more materials selected from the following list: paper, paperboard, cardboard, parchment paper, supercalendered paper (for example glassine), tracing paper, cellulose films, coated paper (for example PVOH paper), and metal foil.

[0043] The first cover may have a laminate structure comprising at least a first layer and a second layer, the first layer having a different material composition to the second layer. The first layer may comprise or consist of paper, paperboard or cardboard. The second layer may comprise or consist of one or more of a metal foil and a polymer film.

[0044] Laterally opposed flap portions of the first cover may be folded to overlie or define corresponding laterally opposed side walls of the aerosol-generating article. Preferably, longitudinally opposed ends of the aerosol-generating article may be free of any coverage by the first cover. The first cover may be arranged to be confined to overlying one of the upper surface and the lower surface of the article, and overlying or defining corresponding laterally opposed side walls of the article.

[0045] Longitudinally opposed flap portions of the first cover may be folded to overlie or define corresponding longitudinally opposed side walls of the aerosol-generating article. Preferably, laterally opposed ends of the aerosol-generating article may be free of any coverage by the first cover. The first cover may be arranged to be confined to overlying one of the upper surface and the lower surface of the article, and overlying or defining corresponding longitudinally opposed side walls of the article. The first cover may have a thickness of between 20 microns and 500 microns, for example between 20 microns and 150 microns, for example between 20 microns and 80 microns.

[0046] The first cover may have a grammage of between 30 and 100 grams per square metre, for example between 30 and 75 grams per square metre, for example between 40 and 60 grams per square metre, for example about 50 grams per square metre.

[0047] The upper and lower surfaces may preferably be aligned perpendicular to a longitudinal axis of the aerosol-generating article. The longitudinal axis may preferably extend along the x direction.

[0048] Preferably, the upper and lower surfaces may be substantially planar. The planar upper and lower surfaces may also be aligned substantially parallel to each other.

[0049] The upper and lower surfaces may be outwardly convex.

[0050] The aerosol-generating article may comprise a taggant defined on or within the flap portion of the first cover. It is likely that heat would be applied the aerosol-generating article via one or both of the upper surface and the lower surface - for example, through a heating element being placed in contact with or in proximity to the upper or lower surface. When heated from above or below in such a manner, the side wall of the article overlaid or defined by the flap portion of the first cover would likely encounter a lower level of heating than the upper or lower surface to which heat is applied. The lower level of heating associated with the side wall of the article reduces the likelihood of the taggant becoming degraded as a result of heating of the article. The taggant may take one of many forms. The taggant may serve as a means of identifying one or more characteristics of the aerosol-generating article, such as the type of aerosol-forming substrate employed in the article and a heating profile to be employed by an aerosol-generating device in heating the substrate of the article. The taggant may also serve as a means of verifying or determining the origin of aerosol-generating article and so may act as an anti-counterfeiting measure.

[0051] At least one of colour coding, one or more QR codes, text and one or more images are defined on an outward-facing surface of the flap portion of the first cover. Such features may serve as a taggant readable by a scanner (for example, a scanner incorporated into the aerosol-generating device) or even by the human eye.

[0052] The aerosol-generating article may also comprise a second cover, the second cover folded to overlie the other of the upper surface and the lower surface such that the first and second covers overlie different ones of the upper surface and the lower surface.

[0053] A flap portion of the second cover may be folded to overlie or define a side wall of the aerosolgenerating article.

[0054] The flap portion of the first cover and the flap portion of the second cover may overlie or define different side walls of the aerosol-generating article. Alternatively, the flap portion of the first cover and the flap portion of the second cover may overlie each other.

[0055] The first cover and (where present) the second cover may advantageously define one or more exterior surfaces of the aerosol-generating article.

[0056] 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 aerosolgenerating 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.

[0057] 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%.

[0058] 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, the upper layer forming the substantially planar upper surface and the lower layer forming the substantially planar lower surface. At least one of the upper and lower layers may comprise or consist of aerosol-forming substrate.

[0059] According to the present disclosure, there may be provided an aerosol-generating article for use with an aerosol-generating device to generate an aerosol. By way of example, the aerosol-generating article may be as described in any of the preceding paragraphs of the present disclosure. The aerosol-generating article may comprise 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 may comprise or consist of an aerosol-forming substrate. The article may further comprise a first cover, the first cover arranged to overlie one of an upper surface and a lower surface of the aerosol-generating article. A flap portion of the first cover may be folded to overlie or define a side wall of the aerosol-generating article.

[0060] The corrugated layer may preferably define the side wall of the aerosol-generating article which is overlaid by the flap portion of the first cover.

[0061] Conveniently, the first planar layer defines one of the upper surface and the lower surface, and the second planar layer defines the other of the upper surface and the lower surface.

[0062] The first cover may be as defined and have the same characteristics and features as described in any of the preceding paragraphs of the present disclosure. For completeness, some of these characteristics and features are repeated below: The first cover may be configured to limit, prevent or inhibit the passage of moisture across the thickness of the first cover. In this manner, the first cover may facilitate preventing excessive moisture absorption by the aerosol-generating article, especially by surfaces of the aerosol-generating article overlaid by the first cover where such surfaces of the aerosol-generating article have a greater level of permeability than the first cover. As previously stated above, limiting, preventing or inhibiting the passage of moisture into the aerosol-generating article may avoid or limit any reduction in the flexural stiffness of the aerosol-generating article. Similarly, limiting, preventing or inhibiting the passage of moisture into the aerosol-generating article (especially into the aerosol-forming substrate of the article) may avoid the user receiving an unpleasant user experience on heating of substrate during use of the aerosol-generating article with an aerosol-generating device.

[0063] The first cover may have a permeability of between 1 to 10 Coresta units, for example between 1 to 5 Coresta units, for example between 1 to 3 Coresta units.

[0064] Preferably, the first cover comprises one or a combination of materials selected from a group consisting of parchment paper, supercalendered paper (for example glassine), tracing paper, cellulose films, coated paper (for example PVOH paper), and metal foil. These specified materials facilitate limiting or preventing the passage of moisture across the thickness of the first cover.

[0065] The materials of the above-mentioned group are preferably in sheet form

[0066] The flap portion of the first cover may overlie a side wall of the aerosol-generating article, the first cover having a permeability less than the side wall. In this manner, the flap portion of the first cover may limit, prevent or inhibit the passage of moisture through the side wall of the aerosol-generating article.

[0067] The flap portion of the first cover may overlie and be bonded to a side wall of the aerosol-generating article, for example by use of an adhesive. In this manner, the flap portion of the cover may enhance the flexural stiffness of the aerosol-generating article as a whole.

[0068] The aerosol-generating article may be free of adhesive at an interface between the first cover and the respective one of the upper surface and the lower surface overlaid by the first cover.

[0069] As described in preceding paragraphs of the present disclosure, the aerosol-generating article may include a second cover in addition to the first cover, the second cover being as defined and having the same characteristics and features as described in any of the preceding paragraphs of the present disclosure.

[0070] 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, aerosolgenerating article to be produced using high speed production methods similar to those used for production of corrugated cardboard.

[0071] According to the present disclosure, there may be provided an aerosol-generating article for use with an aerosol-generating device to generate an aerosol. By way of example, the aerosol-generating article may be as described in any of the preceding paragraphs of the present disclosure. The aerosol-generating article may comprise a first planar external surface, a second planar external surface, a cavity and a frame. The frame is positioned between the first planar external surface and the second planar external surface. The frame at least partially defines the cavity. The aerosol-generating article comprises an aerosol-forming substrate. The aerosol-generating article may comprise an air inlet and an air outlet, and an airflow passage extending between the air inlet and the air outlet through the cavity. The article may further comprise a first cover, the first cover arranged to overlie one of the first planar external surface and the second planar external surface. A flap portion of the first cover may be folded to overlie or define a side wall of the frame.

[0072] Preferably, the air inlet and air outlet remain uncovered by the first cover. In this manner, air flow through the aerosol-generating article is not impeded.

[0073] Preferably, the air inlet and air outlet are defined in the frame, for example in opposed side walls of the frame.

[0074] The first cover may be as defined and have the same characteristics and features as described in any of the preceding paragraphs of the present disclosure. For completeness, some of these characteristics and features are repeated below:

[0075] The first cover may be configured to limit, prevent or inhibit the passage of moisture across the thickness of the first cover. For example, the first cover may have a permeability less than the side wall of the frame. Where the flap portion of the first cover overlies a side wall of the frame, the flap portion of the first cover may limit, prevent or inhibit the passage of moisture through the side wall of the frame into the cavity and / or the aerosol-forming substrate. These advantages may be particularly relevant if the frame is made of an absorbent material, such as paper or cardboard. Similarly, where the flap portion of the first cover defines a side wall of the frame, the flap portion of the first cover may limit, prevent or inhibit the passage of moisture into the cavity and / or the aerosol-forming substrate. As previously stated above, limiting, preventing or inhibiting the passage of moisture into the aerosol-generating article may avoid or limit any reduction in the flexural stiffness of the aerosol-generating article. Similarly, limiting, preventing or inhibiting the passage of moisture into the aerosol-generating article (especially into the aerosol-forming substrate of the article) may avoid the user receiving an unpleasant user experience on heating of substrate during use of the aerosol-generating article with an aerosol-generating device.

[0076] Preferably, the first cover may be configured to be impermeable to water or water.

[0077] The first cover may have a permeability of between 1 to 10 Coresta units, for example between 1 to 5 Coresta units, for example between 1 to 3 Coresta units.

[0078] Preferably, the first cover comprises one or a combination of materials selected from a group consisting of parchment paper, supercalendered paper (for example glassine), tracing paper, cellulose films, coated paper (for example PVOH paper), and metal foil. These specified materials facilitate limiting or preventing the passage of moisture across the thickness of the first cover.

[0079] The materials of the above-mentioned group are preferably in sheet form

[0080] The flap portion of the first cover may overlie and be bonded to the side wall of the frame, for example by use of an adhesive. In this manner, the flap portion of the cover may enhance the flexural stiffness of the frame and of the aerosol-generating article as a whole.

[0081] The aerosol-generating article may be free of adhesive at an interface between the first cover and the respective one of the first planar external surface and the second planar external surface overlaid by the first cover.

[0082] As described in preceding paragraphs of the present disclosure, the aerosol-generating article may include a second cover in addition to the first cover, the second cover being as defined and having the same characteristics and features as described in any of the preceding paragraphs of the present disclosure. Preferably, an aerosol-forming substrate is positioned between the first planar external surface and the second planar external surface.

[0083] 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. Advantageously, the frame may allow the aerosol-generating article to be relatively thin whilst maintaining structural rigidity.

[0084] 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.

[0085] The cavity may be substantially empty.

[0086] Aerosol-forming substrate may be positioned within the cavity.

[0087] A corrugated layer may be positioned within the cavity.

[0088] The frame may be a planar frame.

[0089] The frame may have a height between 50 percent and 95 percent of the height of the aerosolgenerating article. The frame may have a height between 60 percent and 95 percent of the height of the aerosol-generating article. The frame may have a height between 70 percent and 95 percent of the height of the aerosol-generating article. The frame may have a height between 80 percent and 95 percent of the height of the aerosol-generating article.

[0090] The frame may have a height between 1 millimetre and 5.5 millimetres. The frame may have a height between 1 millimetre and 5 millimetres. Preferably, the frame may have a height between 1 .5 millimetres and 5 millimetres.

[0091] The frame may be made from or comprise a biodegradable material. The frame may be made entirely from a biodegradable material.

[0092] The frame may be made from or comprise a cellulosic material. The cellulosic material may comprise a sheet of cellulosic material. The cellulosic material may comprise cellulose fibres. The cellulosic material may be paper, paperboard, or cardboard. The frame may be made from or comprise a plant material, such as tobacco. The frame may be made entirely from a cellulosic material.

[0093] The frame may be a unitary component. Alternatively, the frame may comprise two or more layers. That is, the frame may have a laminated structure.

[0094] 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 10 millimetres and 40 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.

[0095] 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 1 1 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.

[0096] The 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), an oval, a circle, or a combination thereof. Where the aerosol-generating 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 aerosolgenerating 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.

[0097] The aerosol-generating article may consist entirely of aerosol-forming substrate. Alternatively, the aerosol-forming substrate may be one of a plurality of component parts of the aerosol-generating article.

[0098] 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.

[0099] The aerosol-forming substrate may comprise one or more organic materials such as tobacco, mint, tea and cloves. The aerosol-forming substrate may comprise one or more of: herb leaf, tobacco leaf, fragments of tobacco ribs, reconstituted tobacco, homogenised tobacco such as cast leaf, extruded tobacco, expanded tobacco, aerosol-generating films and gel compositions.

[0100] The aerosol-forming substrate may comprise or consist of homogenised tobacco material, for example a reconstituted tobacco material or a cast leaf tobacco material.

[0101] The aerosol-forming substrate may be in the form of shredded aerosol-generating material. The shredded aerosol-generating material may comprise one or more of: strips and strands of aerosolgenerating material, such as strips and strands of tobacco or homogenised tobacco material. The shredded aerosol-generating material may be in the form of a shredded sheet of homogenised tobacco material.

[0102] The aerosol-forming substrate may be cut filler. The aerosol-forming substrate may be tobacco cut filler. The cut filler may comprise one or more of bright tobacco, dark tobacco, aromatic tobacco and filler tobacco. 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. Examples of aromatic tobaccos are Oriental Turkey, Greek Oriental, semi-oriental tobacco but also Fire Cured, US Burley, such as Perique, and Rustica. Examples of dark tobacco are Dark Cured Brazil Galpao, Burley Malawi or other African Burley, Sun Cured or Air Cured Indonesian Kasturi. As used herein, the term “cut filler” is used to describe a blend of shredded plant material, such as tobacco plant material, including, in particular, one or more of leaf lamina, processed stems and ribs, homogenised plant material.

[0103] The aerosol-forming substrate may be in the form of a sheet of aerosol-generating material. As used herein, the term “sheet” describes a laminar element having a width and length substantially greater than the thickness thereof. The sheet of aerosol-generating material may be a sheet of plant material. The sheet of aerosol-generating material may be a sheet of tobacco material. The sheet of aerosol-generating material may be a sheet of homogenised tobacco material, such as a cast leaf sheet.

[0104] The aerosol-forming substrate may comprise a bound collection of strips, strands or particles of tobacco material. The aerosol-forming substrate may be in the form of a compressed plug of tobacco material; for example, in which a plug having a substantially circular cross-section in an initial state of the plug is compressed into a flatter cross-sectional profile in a subsequent state of the plug. The tobacco material may be enclosed by a wrapper. The aerosol-forming substrate may be in the form of strips, strands or particles of tobacco material bound together in a binder matrix.

[0105] 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: 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 aerosol-former to be or comprise one or both of glycerine and propylene glycol. The aerosol former may consist of glycerine or propylene glycol or of a combination of glycerine and propylene glycol.

[0106] The aerosol-forming substrate may have an aerosol-former content greater than or equal to 1 , 2, 5, 10, or 15 percent by weight on a dry weight basis. The aerosol-forming substrate may have an aerosolformer content greater than or equal to 15 percent by weight on a dry weight basis, for example greater than 20 by weight on a dry weight basis, or greater than 25 by weight on a dry weight basis, or greater than 30 by weight on a dry weight basis, or greater than 40 by weight on a dry weight basis, or greater than 50 by weight on a dry weight basis.

[0107] The aerosol-forming substrate may have an aerosol-former content less than or equal to 30 percent by weight on a dry weight basis, less than or equal to 25 percent by weight on a dry weight basis, or less than or equal to 20 percent by weight on a dry weight basis. That is, the aerosol-generating material may have an aerosol-former content less than or equal to 30 by weight on a dry weight basis, less than or equal to 25 by weight on a dry weight basis, or less than or equal to 20 by weight on a dry weight basis.

[0108] The aerosol-forming substrate may have an aerosol-former content between 1 percent and 30 percent by weight on a dry weight basis, between 1 percent and 25 percent by weight on a dry weight basis, or between 1 percent and 20 percent by weight on a dry weight basis.

[0109] The aerosol-forming substrate 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.

[0110] The aerosol-forming substrate 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.

[0111] The aerosol-forming substrate 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.

[0112] The aerosol-forming substrate may comprise nicotine. The aerosol-forming substrate may comprise natural nicotine, or synthetic nicotine, or a combination of natural nicotine and synthetic nicotine. The aerosol-forming substrate 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.

[0113] 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.

[0114] The aerosol-forming substrate may comprise one or more botanicals. For example, the aerosolforming substrate may comprise about 1 to 90 %, 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, Rooibos, Star Anise, Thyme, Anethum, Chamomile and compounds of those.

[0115] The aerosol-forming substrate 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 substrate may be a homogenised tobacco material with a moisture of about 5 to 25%, preferably of about 7 to 15%, at final product state.

[0116] The aerosol-forming substrate may comprise a binder. For example, the aerosol-forming substrate 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 carboxymethyl, celluloses; dextran; and xanthan gum. A preferable binder is guar.

[0117] 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 aerosolforming material retained within a porous matrix. The aerosol-forming substrate may comprise a gel aerosol-forming material.

[0118] According to the present disclosure, an aerosol-generating device for receiving an aerosolgenerating article as disclosed herein, or an aerosol-forming substrate as disclosed herein, may comprise a cavity dimensioned to receive at least a portion of the aerosol-generating article or aerosol-forming substrate, a heater or heating means, a power source for supplying power to the heater or heating means, and a controller to control supply of power to the heater or heating means. The aerosol-generating device is configured to heat an aerosol-forming substrate, for example an aerosol-forming substrate that is a component part of an aerosol-generating article, to form an aerosol, for example an inhalable aerosol.

[0119] The aerosol-generating device may preferably be configured to receive the entirety of the aerosolgenerating article such that the aerosol-generating article is wholly enclosed within the aerosol-generating device.

[0120] The cavity may comprise an opening into which a distal end of the aerosol-generating article can be inserted. The cavity may have any suitable cross-sectional shape. For example, the cavity may have a rectangular transverse cross-section, for example a rectangular cross-section having opposing top and bottom sides that are greater in length than left and right sides.

[0121] Preferably, at least one internal surface of the cavity is a heating surface configured to heat an aerosol-generating article. The heating surface may comprise a heater, for example a resistance heater, or an infra-red heater, or a susceptor configured to be heated by engagement with an inductor. The heating surface may comprise an inductor, for example the surface may comprise a coil arranged to generate a fluctuating electromagnetic field within a space of the cavity. The heating surface may be a surface that is permeable to a fluctuating electromagnetic field, such that an inductor arranged outside the cavity can project a fluctuating electromagnetic field through the heating surface to engage with a susceptor arranged within the cavity.

[0122] As used herein, the term “aerosol-generating article” may refer to an article able to generate, or release, an aerosol.

[0123] 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. An aerosol-forming substrate may comprise an aerosol-forming material. An aerosol-forming substrate may be adsorbed, coated, impregnated, or otherwise loaded onto a carrier or support. An aerosol-forming substrate may conveniently be part of an aerosol-generating article or smoking article.

[0124] As used herein, the term “aerosol-generating device” may refer to a device for use with an aerosolgenerating article to enable the generation, or release, of an aerosol.

[0125] 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 aerosol-generating 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.

[0126] 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.

[0127] As used herein with reference to the invention, the term “nicotine”, is used to describe nicotine, nicotine base or a nicotine salt.

[0128] 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.

[0129] 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.

[0130] 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 irn and about 1000 pirn, for example between 10 pm and about 300 pm.

[0131] 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 byproducts 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.

[0132] 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.

[0133] 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.

[0134] The invention is defined in the claims. However, below there is provided a non-exhaustive list of nonlimiting 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.

[0135] Example Ex1 : An aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosol-generating article comprising: an upper surface; a lower surface; and an aerosol-forming substrate; the aerosol-generating article 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 upper and lower surfaces opposed to and separated from each other in the z direction, wherein the height is less than each of the width and the length; the article further comprising a first cover, the first cover arranged to overlie one of the upper surface and the lower surface, a flap portion of the first cover folded to overlie or define a side wall of the aerosol-generating article.

[0136] Example Ex1 A: An aerosol-generating article according to Ex1 , wherein the first cover is configured to limit, prevent or inhibit the passage of moisture and / or aerosol across the thickness of the first cover. Example Ex2: An aerosol-generating article according to Ex1 or Ex1 A, wherein the first cover is configured to be impermeable to water or air.

[0137] Example Ex3: An aerosol-generating article according to any one of Ex1 to Ex2, wherein the first cover has a permeability of between 1 to 10 Coresta units, for example between 1 to 5 Coresta units, for example between 1 to 3 Coresta units.

[0138] Example Ex3A: An aerosol-generating article according to any one of Ex1 to Ex3, wherein the first cover comprises one or a combination of materials selected from a group consisting of parchment paper, supercalendered paper (for example glassine), tracing paper, cellulose films, coated paper (for example PVOH paper), and metal foil.

[0139] Example Ex4: An aerosol-generating article according to any one of Ex1 to Ex3A, wherein the flap portion of the first cover overlies a side wall of the aerosol-generating article, the first cover having a permeability less than the side wall.

[0140] Example Ex5: An aerosol-generating article according to any one of Ex1 to Ex4, wherein the flap portion of the first cover overlies and is bonded to a side wall of the aerosol-generating article, for example by use of an adhesive.

[0141] Example Ex5a: An aerosol-generating article according to any one of Ex1 to Ex5, wherein the aerosol-generating article is free of adhesive at an interface between the first cover and the respective one of the upper surface and the lower surface overlaid by the first cover.

[0142] Example Ex6: An aerosol-generating article according to any one of Ex1 to Ex5a, wherein the aerosol-generating article comprises a frame disposed between the upper surface and the lower surface, the frame at least partially defining a cavity, the portion of the first cover folded to overlie or define a side wall of the frame.

[0143] Example Ex7: An aerosol-generating article according to Ex6, wherein the first cover has a permeability less than that of the frame.

[0144] Example Ex8: An aerosol-generating article according to Ex7, wherein the permeability of the first cover is no more than 20% of the permeability of the frame, for example no more than 15% of the permeability of the frame, for example no more than 10% of the permeability of the frame, for example no more than 5% of the permeability of the frame, for example no more than 2.5% of the permeability of the frame.

[0145] Example Ex9: An aerosol-generating article according to any one of Ex6 to Ex8, wherein the side wall of the frame has a thickness defined between an inner periphery and an outer periphery of the side wall of between 0.5 millimetres and 1 .5 millimetres, for example between 0.5 millimetres and 1 .25 millimetres, for example between 0.5 millimetres and 1 millimetre, for example between 0.5 millimetres and 0.8 millimetres.

[0146] Example Ex10: An aerosol-generating article according to Ex9, wherein the flap portion of the first cover overlies and is bonded to the side wall of the frame.

[0147] Example Ex1 1 : An aerosol-generating article according to any one of Ex6 to Ex10, wherein the frame has a height within a range of between 1 .5 mm and 5 mm, for example between 1 .5 millimetres and 4 millimetres, for example between 1 .5 millimetres and 3 millimetres.

[0148] Example Ex12: An aerosol-generating article according to any one of Ex6 to Ex1 1 , wherein at least part of the aerosol-forming substrate is located within the cavity. Example Ex13: An aerosol-generating article according to any one of Ex6 to Ex12, wherein the frame comprises a plurality of layers successively arranged over one another along the z direction, a flap portion of at least one of the layers being folded to extend along the z-direction to overlie or be overlaid by the flap portion of the first cover.

[0149] Example Ex14: An aerosol-generating article according to Ex13, wherein the flap portion of the layer or layers is bonded to the flap portion of the first cover.

[0150] Example Ex15: An aerosol-generating article according to either one of Ex13 or Ex14, wherein each of the plurality of layers are arranged in an x-y plane.

[0151] Example Ex16: An aerosol-generating article according to any one of Ex1 to Ex15, wherein the flap portion of the first cover is folded over itself or rolled over itself to define a plurality of layers for the flap portion of the first cover.

[0152] Example Ex17: An aerosol-generating article according to Ex16, wherein the plurality of layers of the flap portion of the first cover are bonded to each other, for example by use of an adhesive.

[0153] Example Ex18: An aerosol-generating article according to any one of Ex1 to Ex17, wherein the first cover is formed from one or more materials selected from the following list: paper, paperboard or cardboard, parchment paper, supercalendered paper (for example glassine), tracing paper, cellulose films, coated paper (for example PVOH paper), and metal foil.

[0154] Example Ex19: An aerosol-generating article according to any one of Ex1 to Ex18, wherein the first cover has a laminate structure comprising at least a first layer and a second layer, the first layer having a different material composition to the second layer.

[0155] Example Ex20: An aerosol-generating article according to Ex19, wherein the first layer comprises or consists of paper, paperboard or cardboard.

[0156] Example Ex21 : An aerosol-generating article according to either one of Ex19 or Ex20, wherein the second layer comprises or consists of one or more of a metal foil and a polymer film.

[0157] Example Ex22: An aerosol-generating article according to any one of Ex1 to Ex21 , wherein laterally opposed flap portions of the first cover are folded to overlie or define corresponding laterally opposed side walls of the aerosol-generating article.

[0158] Example Ex23: An aerosol-generating article according to Ex22, wherein longitudinally opposed ends of the aerosol-generating article are free of any coverage by the first cover.

[0159] Example Ex24: An aerosol-generating article according to any one of Ex1 to Ex22, wherein longitudinally opposed flap portions of the first cover are folded to overlie or define corresponding longitudinally opposed side walls of the aerosol-generating article.

[0160] Example Ex25: An aerosol-generating article according to Ex24, wherein laterally opposed ends of the aerosol-generating article are free of any coverage by the first cover.

[0161] Example Ex26: An aerosol-generating article according to any one of Ex1 to Ex25, wherein the first cover has a thickness of between 20 microns and 500 microns, for example between 20 microns and 150 microns, for example between 20 microns and 80 microns.

[0162] Example Ex27: An aerosol-generating article according to any one of Ex1 to Ex26, wherein the first cover has a grammage of between 30 and 100 grams per square metre, for example between 30 and 75 grams per square metre, for example between 40 and 60 grams per square metre, for example about 50 grams per square metre. Example Ex28: An aerosol-generating article according to any one of Ex1 to Ex27, wherein the upper and lower surfaces are aligned perpendicular to a longitudinal axis of the aerosol-generating article.

[0163] Example Ex29: An aerosol-generating article according to any one of Ex1 to Ex28, wherein the upper and lower surfaces are substantially planar.

[0164] Example Ex30: An aerosol-generating article according to any one of Ex1 to Ex28, wherein the upper and lower surfaces are outwardly convex.

[0165] Example Ex31 An aerosol-generating article according to any one of Ex1 to Ex30, wherein the aerosol-generating article comprises a taggant defined on or within the flap portion of the first cover.

[0166] Example Ex32: An aerosol-generating article according to any one of Ex1 to Ex31 , wherein at least one of colour coding, one or more QR codes, text and one or more images are defined on an outwardfacing surface of the flap portion of the first cover.

[0167] Example Ex33: An aerosol-generating article according to any one of Ex1 to Ex32, wherein the aerosol-generating article comprises a second cover, the second cover folded to overlie the other of the upper surface and the lower surface such that the first and second covers overlie different ones of the upper surface and the lower surface.

[0168] Example Ex34: An aerosol-generating article according to Ex33, wherein a flap portion of the second cover is folded to overlie or define a side wall of the aerosol-generating article.

[0169] Example Ex35: An aerosol-generating article according to Ex34, wherein the flap portion of the first cover and the flap portion of the second cover overlie or define different side walls of the aerosol-generating article.

[0170] Example Ex36: An aerosol-generating article according to Ex34, wherein the flap portion of the first cover and the flap portion of the second cover overlie each other.

[0171] Examples will now be further described with reference to the figures in which:

[0172] Figure 1 A is a perspective side view of an aerosol-generating article according to a first embodiment of the present disclosure;

[0173] Figure 1 B is a schematic transverse cross-sectional view of the aerosol-generating article of figure 1 A;

[0174] Figure 2A is a perspective side view of an aerosol-generating article according to a second embodiment of the present disclosure;

[0175] Figure 2B is a schematic transverse cross-sectional view of the aerosol-generating article of figure 2A;

[0176] Figures 3A to 3E are schematic transverse cross-sectional views of different embodiments of cover arrangements of an aerosol-generating article;

[0177] Figure 4 is a schematic end view of an aerosol-generating article according to a further embodiment of the present disclosure;

[0178] Figure 5 is a schematic side view of the aerosol-generating article of figure 4;

[0179] Figure 6 is a schematic plan view of the aerosol-generating article of figure 4;

[0180] Figure 7 shows a schematic illustration of a corrugated element as used in the aerosol-generating article of figure 4;

[0181] Figure 8 shows a perspective view of an aerosol-generating article according to a further embodiment of the present disclosure; Figure 9 shows an exploded perspective view of the aerosol-generating article of figure 8;

[0182] Figure 10 shows a further exploded perspective view of the aerosol-generating article of figure 8;

[0183] Figure 1 1 shows a schematic transverse cross-sectional view of the aerosol-generating article of figure 8;

[0184] Figure 12 shows a schematic longitudinal cross-sectional view of the aerosol-generating article of figure 8;

[0185] Figure 13 shows an exploded perspective view of an aerosol-generating article according to a further embodiment of the present disclosure;

[0186] Figure 14 shows a schematic transverse cross-sectional view of the aerosol-generating article of figure 13;

[0187] Figure 15 shows a schematic lateral cross-sectional view of the aerosol-generating article of figure 13.

[0188] Figure 16 shows a schematic view of an aerosol-generating device according to an embodiment of the present disclosure, the device configured to engage with an aerosol-generating article, for example the aerosol-generating article of any of figures 1 to 15;

[0189] Figure 17 shows a schematic end view of the aerosol-generating device of figure 16;

[0190] Figure 18 is a schematic view showing an aerosol-generating article (for example, the aerosolgenerating article of any of figures 1 to 15) in engagement with the aerosol-generating device of figure 16.

[0191] Figure 19 is a schematic view of an alternative embodiment to that of figures 16 to 18, showing an aerosol-generating article in engagement with an aerosol-generating device.

[0192] Figures 1 A and 1 B illustrate a perspective side view and a transverse cross-sectional view of an aerosol-generating article 100 according to a first embodiment of the present disclosure. The aerosolgenerating article 100 has a cuboid body 105 having upper and lower surfaces 1 10, 120 which are flat or planar and substantially parallel to each other. The aerosol-generating article 100 also has a cover 130 positioned to overlie three surfaces of the cuboid body 105. The cover 130 is shown cross-hatched in figures 1 A and 1 B. A central portion 131 of the cover 130 extends over the upper surface 1 10. Laterally opposed portions 132, 133 of the cover 130 are folded about corresponding fold lines 134, 135 defined in the cover to overlie laterally opposed side surfaces 103, 104 of the cuboid body 105. The fold lines 134, 135 define interfaces between the central portion 131 of the cover 130 and respective ones of the laterally opposed portions 132, 133 of the cover. The laterally opposed portions 132, 133 define flaps or wings. An adhesive 136 is used to secure the laterally opposed flaps 132, 133 of the cover 130 to the side surfaces 103, 104 of the cuboid body 105. No adhesive is present at the interface between the central portion 131 of the cover 130 and the upper surface 1 10 of the cuboid body 105. The cover 130 does not extend over the lower surface 120 or either of axially opposed end surfaces 101 , 102 of the cuboid body 105. However, in an alternative embodiment, the cover 130 may be adapted to instead be confined to overlie the upper surface 1 10 and axially opposed end surfaces 101 , 102 of the cuboid body 105.

[0193] A taggant 137 is provided on the outer surface of the flap 132 of the cover 130. The taggant may be in the form of a QR code (as shown in figure 1 A), or may be in the form of a chemical marker. The taggant 137 may contain information authenticating the origin of the aerosol-generating article 100, or one or more characteristics of the aerosol-generating article (for example, the type of aerosol-forming substrate employed within the article), or the heating profile to be used in heating the aerosol-forming substrate of the article. The taggant 137 may be read by a scanner (not shown). Such a scanner may be a dedicated standalone scanner, or preferably be integrated into an aerosol-generating device adapted to receive the aerosol-generating article 100. In other embodiments, text or imagery may be imprinted on the cover 130. Such text or imagery may include branding relating to the origin of the aerosol-generating article 100 or instructions relating to use of the aerosol-generating article.

[0194] The cover 130 is formed of a coated paper, such as PVOH paper. The cover 130 has a thickness of about 80 microns and a grammage of 50 grams per square metre. The use of coated paper makes the cover 130 substantially impermeable to the passage of moisture and aerosol across the thickness of the cover. In this manner, the cover 130 reduces, prevents or inhibits the entry of moisture into the article 100 through the upper surface 1 10 and laterally opposed side surfaces 103, 104 of the cuboid body 105. Similarly, the cover 130 may also reduce, prevent or inhibit loss of aerosol from the aerosol-generating article 100, for example loss of aerosol through the opposed side surfaces 103, 104 of the cuboid body 105. In other embodiments, the cover 130 may comprise one or a combination of materials selected from a group consisting of parchment paper, supercalendered paper (for example glassine), tracing paper, cellulose films, coated paper (for example PVOH paper), and metal foil. The cover 130 may have a laminate construction formed of different layers. For such a laminate construction, one or more of the layers may be formed of the materials specified in this paragraph or alternatively be formed of any other suitable materials for making the cover 130 substantially impermeable to moisture.

[0195] The aerosol-generating article 100 comprises an aerosol-forming substrate (not shown). In one embodiment, the cuboid body 105 of the aerosol-generating article 100 may consist substantially of aerosolforming 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 an interior of the aerosol-generating article 100. The aerosol-forming substrate may at least partially define one or both of the upper and lower surfaces 1 10, 120 and / or one or both of the laterally-opposed side surfaces 103, 104 of the cuboid body 105.

[0196] A suitable aerosol-forming substrate may be homogenised tobacco.

[0197] The aerosol-generating article 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.

[0198] Figures 2A and 2B illustrate a perspective side view and a transverse cross-sectional view of an aerosol-generating article 200 according to a second embodiment of the present disclosure, being a variant of aerosol-generating article 100. Features in common with aerosol-generating article 100 are referred to with like reference signs but commencing with numeral 2 instead of numeral 1 . An air flow path 240 is defined through the interior of the aerosol-generating article 200. The air flow path 240 extends between the opposed first and second ends 201 , 202 of the aerosol-generating article 200. The first and second ends 201 , 202 also define axial opposed end surfaces of the cuboid body 205. The first end 201 may define a distal end of the aerosol-generating article 200, and the second end 202 may define a proximal or mouth end of the aerosol-generating article. 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 substrate of the aerosol-generating article 200. In a similar manner to the cover 130 of aerosol-generating article 100, the cover 230 of aerosol-generating article 200 is confined to covering the upper surface 210 and laterally opposed side surfaces 203, 204 of the cuboid body 205, whilst not extending over the lower surface 220 or either of axially opposed end surfaces 201 , 202 of the cuboid body 205. However, in an alternative embodiment, the cover 230 may be adapted to instead be confined to overlie the upper surface 210 and axially opposed end surfaces 201 , 202 of the cuboid body 205.

[0199] Figures 3A to 3E illustrate various alternative cover configurations for different aerosol-generating articles 300a-e. Figures 3A to 3E show schematic transverse cross-section views through the various aerosol-generating articles 300a-e. Each of the articles 300a-e has a generally cuboid geometry (in common with aerosol-generating articles 100, 200), with a cuboid body 305a-e overlaid by one or more covers 330a-e, 340c-e.

[0200] The aerosol-generating article 300a of figure 3A has a cover 330a corresponding to that shown for the aerosol-generating article 100. The cover 330a is arranged to overlie upper surface 310a and laterally opposed side surfaces 303a, 304a of the cuboid body 305a of the article 300a, whilst leaving the lower surface 320a uncovered. The cover 330a has a generally planar central portion 331 a overlying upper surface 310a, and laterally opposed flaps or wings 332a, 333a which are folded to extend linearly along the side surfaces 303a, 304a of the cuboid body 305a of the article 300a.

[0201] The aerosol-generating article 300b of figure 3B has a cover 330b which differs from the cover 330a of figure 3A in that each of the laterally opposed flaps or wings 332b, 333b of the cover 330b are successively folded or rolled over themselves to define a multi-layered structure overlying each of the laterally opposed side surfaces 303b, 304b of the cuboid body 305b of the article 300b. Adhesive (not shown) may be provided between the different layers of the successively folded or rolled laterally opposed flaps or wings 332b, 333b to retain the different layers in secure, stable alignment relative to each other.

[0202] The aerosol-generating article 300c of figure 3C has first and second covers 330c, 340c. The first cover 330c corresponds in structure to the cover 330a of figure 3A, being arranged to overlie upper surface 310c and laterally opposed side surfaces 303c, 304c of the cuboid body 305c of the article 300c. However, the second cover 340c is confined to overlie the lower surface 320c of the cuboid body 305c of the article 300c. In this manner, the first and second covers 330c, 340c collectively define a band or loop extending around a perimeter of the cuboid body 305c of the aerosol-generating article 300c. For the illustrated embodiment, the first and second covers 330c, 340c do not overlap one another. The aerosol-generating article 300d of figure 3D has first and second covers 330d, 340d. First cover 330d is confined to overlie the upper surface 31 Od and the side surface 303d of the cuboid body 305d of the article 300d, whereas cover 340d is confined to overlie the lower surface 320d and the side surface 304d of the cuboid body 305d of the article 300d. In this manner, the first and second covers 330d, 340d collectively define a band or loop extending around a perimeter of the cuboid body 305d of the aerosol-generating article 300d. For the illustrated embodiment, the first and second covers 330c, 340c do not overlap one another.

[0203] The aerosol-generating article 300e of figure 3E has first and second covers 330e, 340e. The second cover 340e overlies lower surface 320e of the cuboid body 305e (through central portion 341 e of the second cover 340e) and laterally opposed side surfaces 303e, 304e of the cuboid body 305e (through laterally opposed flaps or wings 342e, 343e of the second cover 340e). The first cover 330e overlies upper surface 31 Oe of the cuboid body 305e (through central portion 331 e of the first cover 330e) and the laterally opposed flaps or wings 342e, 343e of the second cover 340e (through laterally opposed flaps or wings 332e, 333e of the first cover 330e). Flap 332e of first cover 330e may be secured to flap 342e of second cover 340e by use of adhesive. Similarly, flap 333e of first cover 330e may be secured to flap 343e of second cover 340e by use of an adhesive.

[0204] Figures 5, 6, and 7 illustrate respectively an end view, a side view, and a plan view of an aerosolgenerating article 400 according to a further embodiment of the present disclosure. The aerosol-generating article 400 comprises a planar upper layer 410, a planar lower layer 420, and an intermediate or separation layer 440 arranged between the upper layer 410 and lower layer 420. A cover 430 is provided, with a central portion 431 of the cover 430 overlying the upper layer 410 and laterally opposed flaps or wings 432, 433 of the cover 430 folded to be generally perpendicular to the central portion 431 . An adhesive 436 is used to secure the central portion 431 of the cover 430 to the upper layer 410. As can be seen from figure 4, the laterally opposed flaps or wings 432, 433 define laterally opposed sidewalls of the aerosol-generating article 400. It can be seen that cover 430 has a configuration similar to that of the cover 330a of figure 3A. However, in other embodiments, different arrangements of one or more covers may be used in place of cover 430, such as any of the covering arrangements shown in figures 3B to 3E.

[0205] The planar upper layer 410 is formed from a sheet of paper having a thickness of 300 microns. The planar lower layer 420 is formed from a sheet of paper having a thickness of 300 microns. The intermediate layer 440 is a corrugated element formed from a corrugated sheet of aerosol-forming substrate 445. A suitable aerosol-forming substrate may be homogenised tobacco. Thus, the intermediate layer 440 may be formed from a corrugated sheet of homogenised tobacco material 445.

[0206] The cover 430 is formed of a coated paper, such as PVOH paper. The cover 430 has a thickness of about 100 microns and a grammage of 70 grams per square metre.

[0207] Figure 7 illustrates the corrugated sheet of aerosol-forming substrate 445. The corrugations have an amplitude 446 of 3 millimetres and a wavelength 447 of 3 millimetres. The sheet of aerosol-forming substrate 445 forming the intermediate layer 440 has a thickness of 150 microns.

[0208] Points of intersection 451 , 452 between the upper layer 410 and the intermediate layer 440 and between the lower layer 420 and the intermediate layer 440 comprise an adhesive that joins the respective layers.

[0209] The aerosol-generating article 400 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.

[0210] Corrugations of the intermediate layer 440 form a first set of longitudinally extending channels 461 that are bounded by the upper layer 410 and the intermediate layer 440, and a second set of longitudinally extending channels 462 bounded by the lower layer 420 and the intermediate layer 440. The first and second sets of longitudinally extending channels 461 , 462 extend through the length of the aerosol-forming substrate between a proximal end 471 of the substrate 445 and a distal end 472 of the substrate 445. The longitudinally extending channels 461 , 462 define an air-flow path through the substrate 445. The air-flow path, therefore, passes over both sides of the sheet of aerosol-forming substrate 445. The porosity of the aerosol-generating article 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.

[0211] The aerosol-forming substrate 445 may be a sheet of any suitable aerosol-forming substrate.

[0212] During use of the aerosol-generating article 400, the aerosol-forming substrate 445 is heated up to cause the aerosol-forming substrate 445 to release volatile compounds, which are then entrained in air drawn into the channels 461 , 462 via the distal end 472. The volatile compounds then cool and condense to form an aerosol which may be drawn out of the channels 461 , 462 of the aerosol-generating article 400 via the proximal end 471 .

[0213] Figure 8 shows an aerosol-generating article 400 according to a further embodiment of the present disclosure. Figures 9 and 10 show exploded views of the aerosol-generating article 400 of figure 8. The aerosol-generating article 400 comprises a first planar layer 424 forming a first planar surface 421 , a second planar layer 425 forming a second planar surface 422, and a frame 450 positioned between the first planar layer 424 and the second planar layer 425. The second planar surface 422 is positioned parallel to the first planar surface 421 . A cover 460 is provided which overlies the first planar surface 421 and laterally opposed side surfaces of the frame 450. More specifically, a central portion 461 of the cover 460 overlies the first planar surface 421 . Further, laterally opposed flap or wing portions 462, 463 of the cover 460 are folded about fold lines 464, 465 to be generally perpendicular to the central portion 461 of the cover 460 and overlie laterally opposed side surfaces of the frame 450.

[0214] As shown in figure 9, the frame 450 circumscribes and at least partially defines a cavity 430. Figure 9 shows the cavity 430 in an empty state. Figure 10 shows the cavity 430 filled with aerosol-forming substrate 440. Figures 1 1 and 12 show respective transverse and longitudinal cross-sectional views of the aerosol-generating article 400 when the cavity 430 is filled with aerosol-forming substrate 440.

[0215] The first planar layer 424 and the second planar 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 layer 424 overlies a first end of the cavity 430 and forms a first cavity end wall 431 . The second planar 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 layer 424 and the second planar layer 425 collectively define the cavity 430.

[0216] 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-generating article 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 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-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 about 5 millimetres.

[0217] An air inlet 41 1 and an air outlet 412 are defined by, and extend through, the peripheral wall 451 of the frame 450. More specifically, the air inlet 41 1 extends through the front wall 413 and the air outlet 412 extends through the back wall 414. The air inlet 41 1 and the air outlet 412 have an equivalent diameter of 5 millimetres. An airflow passage extends between the air inlet 41 1 and the air outlet 412 through the cavity 430. As shown in figures 10 to 12, 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-former content of 5 percent by weight on a dry weight basis. As shown, the aerosol- forming substrate 440 fills the entire volume of the cavity 430. The cover 460 does not extend over the air inlet 41 1 or the air outlet 412, thereby avoiding impeding air flow through the aerosol-generating article 400.

[0218] The aerosol-generating article 400 incorporating the cover 460 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 30 millimetres and a length extending in an x dimension of 50 millimetres.

[0219] Although the aerosol-generating article 400 of figures 8 to 12 has a single cover 460 confined to overlying first planar surface 421 and laterally opposed side surfaces of the frame 450, in other embodiments an additional cover may be provided so as to overlie the second planar surface 422. By way of example, a covering arrangement corresponding to any of those shown in figures 3a-e could be used for aerosol-generating article 400.

[0220] Figure 13 shows an aerosol-generating article 500 according to a further embodiment of the present disclosure. Features in common with aerosol-generating article 400 are referred to with like reference signs but commencing with numeral 5 instead of numeral 4. Aerosol-generating article 500 differs from aerosolgenerating article 400 in that the aerosol-forming substrate is in the form of a sheet of aerosol-generating material 540, in particular a corrugated sheet of homogenised tobacco material. Figures 14 and 15 show respective transverse and lateral cross-section views of the aerosol-generating article 500 of figure 13. A cover 560 is provided which overlies the first planar surface 521 of first planar layer 524 and laterally opposed side surfaces of the frame 550. More specifically, a central portion 561 of the cover 560 overlies the first planar surface 521 . Further, laterally opposed flap or wing portions 562, 563 of the cover 560 are folded about fold lines 564, 565 to be generally perpendicular to the central portion 561 of the cover 560 and overlie the laterally opposed side surfaces of the frame 550.

[0221] 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 14, 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 531 and the second cavity end wall 532, respectively.

[0222] The plurality of parallel corrugations form a plurality of channels 545 between the sheet of aerosolgenerating material 540 and the first cavity end wall 531 , and a plurality of channels 546 between the sheet of aerosol-generating material 540 and the second cavity end wall 532. The plurality of channels 545, 546 extend in a longitudinal direction of the aerosol-generating article 500 and form at least a portion of the airflow passage extending between the air inlet 51 1 and the air outlet 512.

[0223] During use of each of the aerosol-generating articles 400, 500, the aerosol-forming substrate 440, 540 is heated up to cause the aerosol-forming substrate 440, 540 to release volatile compounds, which are then entrained in air drawn through the air inlet 41 1 , 51 1 into the cavity 430, 530. The volatile compounds then cool and condense to form an aerosol which may be drawn out of the aerosol-generating article 400, 500 through the air outlet 412, 512.

[0224] Figures 16 and 17 illustrate an aerosol-generating device 6000 configured for use with an aerosolgenerating article 600 comprising or consisting of aerosol-forming substrate 640. The device 6000 is an elongate aerosol-generating device extending between a proximal end 6001 and a distal end 6002. The device 6000 comprises a battery 6010, a controller 6020 and a heater 6030 located within a housing 6040. The controller 6020 controls supply of power from the battery 6010 to the heater 6030. A cavity 6050 is defined in the device 6000, the cavity having an opening 6051 defined in the proximal end 6001 of the device. The opening 6051 is rectangular in shape and is dimensioned to accommodate the transverse cross-section of the aerosol-generating article 600. The cavity 6050 comprises an upper planar surface 6052 and a lower planar surface 6053. The heater 6030 is located in the lower planar surface 6053 to heat a lower surface of the aerosol-generating article 600 inserted into the cavity 6050. An air-flow path is configured to allow air to flow into the cavity 6050 from outside the device 6000.

[0225] Figure 18 illustrates the device 6000 of figure 16 in engagement with the aerosol-generating article 600. There is little tolerance between outer surfaces of the aerosol-generating article 600 and the internal surfaces of the cavity 6050. Thus, there is a snug fit between the aerosol-generating article 600 and the device 6000. As the RTD of the aerosol-generating article 600 is negligible, the RTD of the system formed by the combination of aerosol-generating article 600 and aerosol-generating device 6000 is controlled by the air-flow path defined within the device. When a user has inserted the aerosol-generating article 600 into the cavity 6050, the device 6000 can be operated. The heater 6030 heats a lower surface of the aerosolgenerating article 600, and as a result the aerosol-forming substrate 640 of the aerosol-generating article 600 is heated. Volatile components of the aerosol-forming substrate 640 are evaporated and condense in longitudinal air-flow channels defined within the aerosol-generating article 600 to form an aerosol. The user inhales the aerosol by drawing on the proximal end 601 of the aerosol-generating article 600. Once the aerosol-generating substrate 640 of the aerosol-generating article 600 has been depleted of volatile components, the aerosol-generating article is removed from the cavity 6050 of the device 6000 and disposed of. The aerosol-generating article 600 may be any one of the aerosol-generating articles 100, 200, 300, 400, 500 previously described or any other aerosol-generating article of the present disclosure.

[0226] Although figure 18 shows part of the aerosol-generating article 600 extending outside of the aerosolgenerating device 6000, in other embodiments the entirety of an aerosol-generating article may be wholly enclosed within an aerosol-generating device. By way of example, figure 19 illustrates an alternative embodiment to that of figure 18, with like features referred to by the same reference numbers but with the addition of a prime symbol ’. For the alternative embodiment of figure 19, the entirety of aerosol-generating article 600’ is enclosed within the interior of aerosol-generating device 6000’.

[0227] 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 for use with an aerosol-generating device to generate an aerosol, the aerosol-generating article comprising: an upper surface; a lower surface; and an aerosol-forming substrate; the aerosol-generating article 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 upper and lower surfaces opposed to and separated from each other in the z direction, wherein the height is less than each of the width and the length; the article further comprising a first cover, the first cover arranged to overlie one of the upper surface and the lower surface, a flap portion of the first cover folded to overlie or define a side wall of the aerosol-generating article.

2. An aerosol-generating article according to claim 1 , wherein the first cover is configured to limit, prevent or inhibit the passage of moisture and / or aerosol across the thickness of the first cover.

3. An aerosol-generating article according to either one of claim 1 or claim 2, wherein the first cover comprises one or a combination of materials selected from a group consisting of parchment paper, supercalendered paper (for example glassine), tracing paper, cellulose films, coated paper (for example PVOH paper), and metal foil.

4. An aerosol-generating article according to any one of claims 1 to 3, wherein the flap portion of the first cover overlies a side wall of the aerosol-generating article, the first cover having a permeability less than the side wall.

5. An aerosol-generating article according to any one of claims 1 to 4, wherein the aerosol-generating article is free of adhesive at an interface between the first cover and the respective one of the upper surface and the lower surface overlaid by the first cover.

6. An aerosol-generating article according to any one of claims 1 to 5, wherein the aerosol-generating article comprises a frame disposed between the upper surface and the lower surface, the frame at least partially defining a cavity, the portion of the first cover folded to overlie or define a side wall of the frame, preferably wherein the first cover has a permeability less than that of the frame.

7. An aerosol-generating article according to claim 6, wherein the permeability of the first cover is no more than 20% of the permeability of the frame, for example no more than 15% of the permeability of the frame, for example no more than 10% of the permeability of the frame, for example no more than 5% of the permeability of the frame, for example no more than 2.5% of the permeability of the frame.

8. An aerosol-generating article according to either one of claim 6 or claim 7, wherein the side wall of the frame has a thickness defined between an inner periphery and an outer periphery of the side wall of between 0.5 millimetres and 1 .5 millimetres, for example between 0.5 millimetres and 1 .25 millimetres, for example between 0.5 millimetres and 1 millimetre, for example between 0.5 millimetres and 0.8 millimetres.

9. An aerosol-generating article according to any one of claims 6 to 8, wherein the frame comprises a plurality of layers successively arranged over one another along the z direction, a flap portion of at least one of the layers being folded to extend along the z-direction to overlie or be overlaid by the flap portion ofthe first cover, wherein preferably the flap portion of the layer or layers is bonded to the flap portion of the first cover.

10. An aerosol-generating article according to any one of claims 1 to 9, wherein the flap portion of the first cover is folded over itself or rolled over itself to define a plurality of layers for the flap portion of the first cover.1 1. An aerosol-generating article according to claim 10, wherein the plurality of layers of the flap portion of the first cover are bonded to each other, for example by use of an adhesive.

12. An aerosol-generating article according to any one of claims 1 to 1 1 , wherein laterally opposed flap portions of the first cover are folded to overlie or define corresponding laterally opposed side walls of the aerosol-generating article, preferably wherein longitudinally opposed ends of the aerosol-generating article are free of any coverage by the first cover.

13. An aerosol-generating article according to any one of claims 1 to 12, wherein longitudinally opposed flap portions of the first cover are folded to overlie or define corresponding longitudinally opposed side walls of the aerosol-generating article, preferably wherein laterally opposed ends of the aerosol-generating article are free of any coverage by the first cover.

14. An aerosol-generating article according to any one of claims 1 to 13, wherein the aerosolgenerating article comprises a taggant defined on or within the flap portion of the first cover.

15. An aerosol-generating article according to any one of claims 1 to 14, wherein the aerosolgenerating article comprises a second cover, the second cover folded to overlie the other of the upper surface and the lower surface such that the first and second covers overlie different ones of the upper surface and the lower surface.

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