Aerosol-generating article

Abstract

There is provided an aerosol-generating article (100, 200, 300, 400, 500, 600, 700, 800, 1200, 1300, 1401, 1402) comprising an aerosol-forming substrate and at least one thread (125, 225, 325, 326, 327, 625, 1208). At least a portion of the aerosol-forming substrate is sewn with the at least one thread. A method of manufacture is also provided.

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 to hold them together. 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. It is also an objective of the present disclosure to provide an aerosol-generating article that provides a novel way to hold an aerosol-forming substrate together, or to hold multiple components of an aerosol-generating article together.

[0006] According to the present disclosure, there may be provided an aerosol-generating article comprising an aerosol-forming substrate and at least one thread. At least a portion of the aerosol-forming substrate may be sewn with the at least one thread.

[0007] Thus, according to a first aspect of the present disclosure, there may be provided an aerosolgenerating article comprising an aerosol-forming substrate and at least one thread, wherein at least a portion of the aerosol-forming substrate may be sewn with the at least one thread.

[0008] Advantageously, sewing the aerosol-forming substrate with at least one thread may hold the substrate together, or be able to retain the aerosol-forming substrate in a compressed condition. This may advantageously prevent the aerosol-forming substrate from falling apart or restrict expansion of the substrate to take up more space. Alternatively, or in addition, sewing at least a portion of the aerosolforming substrate with at least one thread may create spaces for airflow or aerosol generation.

[0009] The aerosol-generating article may be for use with an aerosol-generating device to generate an aerosol. The aerosol-generating article may be a planar aerosol-generating article. The aerosol-generating article may have, or be defined by, an article length, an article width, and an article thickness. The article length may be greater than, for example at least 2, 3 or 5 times, the article thickness. The article width may be greater than, for example at least 2, 3 or 5 times, the article thickness. The article length may be greater than the article width. Advantageously, the article thickness being relatively small may reduce a temperature gradient across the article, or across the substrate of the article, during use. This may mean that a greater proportion of the substrate is able to reach a sufficiently high temperature to form an aerosol, without a significant risk of burning the substrate, compared with a thicker article or substrate.

[0010] The terms height and thickness may be used interchangeably herein. Thus, the terms article height and article thickness may be used interchangeably and the terms substrate height and substrate thickness may be used interchangeably.

[0011] Optionally, the article length extends in an article length direction. Optionally, the article width extends in an article width direction. Optionally, the article thickness extends in an article thickness direction. Optionally, the article length direction is perpendicular to the article width direction. Optionally, the article length direction is perpendicular to the article thickness direction. Optionally, the article width direction is perpendicular to the article thickness direction. Optionally, the article length direction, the article width direction, and the article thickness direction are mutually perpendicular. The article length direction may be referred to as the x direction. The article width direction may be referred to as the y direction. The article thickness direction may be referred to as the z direction. The article length may extend from an upstream end to a downstream end of the article.

[0012] Optionally, the article is substantially planar in shape. Optionally, the article is substantially cuboid in shape.

[0013] The aerosol-generating article may comprise an upper surface, for example a substantially planar upper surface. The upper surface may be defined by a length extending in an x direction, for example the article length, and a width extending in a y direction, for example the article width. The aerosol-generating article may comprise a lower surface, for example a substantially planar lower surface. The lower surface may be defined by a length extending in an x direction, for example the article length, and a width extending in a y direction, for example the article width. The upper surface and lower surface may be external surfaces of the article. The upper surface and the lower surface may be vertically spaced from each other by a height defined in a z direction, for example the article thickness. The lower surface may be referred to as a base.

[0014] The aerosol-forming substrate may have, or be defined by, a substrate length, a substrate width, and a substrate thickness. The substrate length may extend in a substrate length direction. The substrate width may extend in a substrate width direction. The substrate thickness may extend in a substrate thickness direction. The substrate length direction, substrate width direction and substrate thickness direction may be mutually perpendicular. The substrate length may be greater than, for example at least 2, 3 or 5 times, the substrate thickness. The substrate width may be greater than, for example at least 2, 3 or 5 times, the substrate thickness. The substrate length may be greater than the substrate width. Advantageously, the substrate thickness being relatively small may reduce a temperature gradient across the substrate during use. This may mean that a greater proportion of the substrate is able to reach a sufficiently high temperature to form an aerosol, without a significant risk of burning the substrate, compared with a thicker substrate.

[0015] The substrate length may extend from an upstream end of the substrate to a downstream end of the substrate. The substrate length direction may align, or be substantially parallel to, the article length direction. The substrate width direction may align, or be substantially parallel to, the article width direction. The substrate thickness direction may align, or be substantially parallel to, the article thickness direction. Aerosol-generating articles according to the present disclosure may preferably be substantially flat articles or substantially planar articles. Such articles may 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 or 25 percent of both the length and width ofthe 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 aerosolgenerating article during heating. For example, where the base ofthe 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.

[0016] Optionally, at least the portion of the aerosol-forming substrate is sewn with the at least one thread to hold the aerosol-forming substrate in a compressed state. Optionally, the compressed state is a compressed state relative to a natural state or a lowest elastic energy state ofthe aerosol-forming substrate. Optionally, the compressed state is a compressed state in the substrate thickness direction. Optionally, the aerosol-forming substrate stores elastic energy in the compressed state.

[0017] Optionally, at least the portion of the aerosol-forming substrate is sewn with the at least one thread to prevent or limit release of stored elastic energy such as the stored elastic energy referred to in the previous sentence. Optionally, at least the portion of the aerosol-forming substrate is sewn with the at least one thread to prevent or limit release ofthe stored elastic energy release through expansion of the aerosolforming substrate, such as through expansion of the aerosol-forming substrate in the substrate thickness direction. Optionally, at least the portion of the aerosol-forming substrate is sewn with the at least one thread to limit expansion of the aerosol-forming substrate, for example in the substrate thickness direction. Optionally, at least a portion of the at least one thread is under tension, for example due to the aerosolforming substrate acting to expand. Optionally, the aerosol-forming substrate sewn with the at least one thread occupies a first volume. Optionally, if the at least one thread were removed, the aerosol-forming substrate would expand to occupy a second volume greater than the first volume. This expansion may be, or mostly be, an expansion in the substrate thickness direction.

[0018] Advantageously, sewing the aerosol-forming substrate with at least one thread may retain the aerosol-forming substrate in a compressed condition. This may advantageously prevent the aerosolforming substrate from expanding to take up more space in the aerosol-generating article. Alternatively, or in addition, this may advantageously help retain the aerosol-forming substrate in a desired shape, or give the aerosol-forming substrate a desired bulk density.

[0019] The aerosol-forming substrate may be or comprise a plug of aerosol-forming material. The aerosolforming substrate may be or comprise one or more sheets of aerosol-forming material.

[0020] Optionally, at least a portion ofthe at least one thread extends through the substrate in a first through direction. Optionally, at least a portion of the at least one thread extends along the substrate in a first along direction. Optionally, at least a portion of the at least one thread extends through the substrate in a second through direction, optionally substantially opposing the first through direction. Optionally, at least a portion of the at least one thread extends along the substrate in a second along direction, optionally substantially parallel to the first along direction. The extensions in this paragraph may occur in the order presented in this paragraph, and may occur one immediately after the other. Thus: optionally, at least a portion of the at least one thread extends: through the substrate in a first through direction; then, optionally immediately, along the substrate in a first along direction; then, optionally immediately, through the substrate in a second through direction, optionally substantially opposing the first through direction; then, optionally immediately, along the substrate in a second along direction, optionally substantially the same as the first along direction.

[0021] The extension of the at least one thread through the substrate as mentioned in the above paragraph may refer to extension of the at least one thread through the substrate thickness, for example from the upper surface to the lower surface of the substrate when in the first through direction, and from the lower surface to the upper surface of the substrate when in the second through direction, or vice versa.

[0022] The extension of the at least one thread along the substrate in the first along direction, as mentioned in the above two paragraphs, may refer to extension of the at least one thread along the upper or lower surface of the substrate. And the extension of the at least one thread along the substrate in the second along direction, as mentioned in the above two paragraphs, may referto extension ofthe at least one thread along the other of the upper or lower surface of the substrate.

[0023] When the at least one thread extends through the substrate, the at least one thread may be in contact with the substrate. When the at least one thread extends along the substrate, the at least one thread may be in contact with the substrate. Alternatively, when the at least one thread extends along the substrate, the at least one thread may be not be in contact with the substrate. For example, when the at least one thread extends along the substrate, a component such as a cover as mentioned later, may be located between the at least one thread and the substrate.

[0024] Optionally, the first through direction is non-perpendicular to the substrate thickness direction, for example substantially parallel to the substrate thickness direction. Optionally, the second through direction is substantially opposite to the first through direction. Optionally, the second through direction is nonperpendicular to the substrate thickness direction, for example substantially parallel to the substrate thickness direction. Advantageously, this may allow the at least one thread to hold the substrate in a compressed condition in the substrate thickness direction. In this context and similar contexts, opposite directions may be considered parallel to one another.

[0025] Optionally, the first along direction is non-perpendicular with the substrate length direction, for example substantially parallel with the substrate length direction. Optionally, the second along direction is non-perpendicular with the substrate length direction, for example substantially parallel with the substrate length direction. For example the at least one thread may form a linear stitching pattern along the aerosolforming substrate in the substrate length direction. Advantageously, a linear stitching pattern may be less costly or less difficult to achieve than other stitching patterns. Advantageously, where the substrate length is longer than the substrate width and substrate thickness, stitching along the substrate length may hold the substrate in a compressed condition better than stitching along the substrate width direction.

[0026] Optionally, the first along direction is non-perpendicular with the substrate width direction, for example substantially parallel with the substrate width direction. Optionally, the second along direction is non-perpendicular with the substrate width direction, for example substantially parallel with the substrate width direction. For example, the at least one thread may form a linear stitching pattern along the aerosol- forming substrate in the substrate width direction. Advantageously, a linear stitching pattern may be less costly or less difficult to achieve than other stitching patterns.

[0027] Optionally, the first along direction is non-perpendicular with the substrate length direction and nonperpendicular with the substrate width direction. Optionally, the second along direction is non-perpendicular with the substrate length direction and non-perpendicular with the substrate width direction. For example, the at least one thread may form a zig-zag stitching pattern along the aerosol-forming substrate, such as along the substrate length and substrate width directions. Advantageously, the along directions of this paragraph may be able to hold the substrate compressed in the substrate thickness direction across substantially an entirety of the length and width of the substrate, and may not require more than one thread.

[0028] Optionally, one or both of the first along direction and the second along direction are directions in a plane formed by the substrate length and the substrate width directions, or the x-y plane.

[0029] Optionally, the at least one thread extends into the substrate in the first through direction at a first location. Optionally, the at least one thread extends out of the substrate in the second through direction at a second location. The first and second locations may both be in the same surface of the aerosol-forming substrate, for example the upper or lower surface of the substrate. Optionally, a distance between the first location and the second location is no more than 10, 5, 3 or 1 millimetres. Optionally, the distance between the first location and the second location is at least 0.2 or 0.5 or 1 millimetres. Optionally, the distance between the first location and the second location is between 0.2 and 10, or 0.2 and 5, or 0.5 and 10, or 0.5 and 5, or 1 and 10, or 1 and 5 millimetres. A compromise must be made with this distance - a smaller distance may advantageously hold the substrate compressed more tightly, with less expansion occurring between the first and second locations, but may result in more thread being required and less space for aerosol-forming material, or may result in thinner, less strong thread being required.

[0030] Optionally, the at least one thread extends through the aerosol-forming substrate at least 5, 10 or 20 times. Advantageously, more extensions of the at least one thread through the substrate may hold the substrate compressed more tightly.

[0031] Optionally, a ratio of a substrate length of the aerosol-forming substrate to a thread length of the at least one thread is between 1 :2 and 1 :50, or between 1 :2 and 1 :20, or between 1 :2 and 1 :10. In this context, the term “thread length of the at least one thread” may refer to an end-to-end measurement of the at least one thread if the at least one thread were removed from the substrate and laid in a straight line.

[0032] The at least one thread may be a single continuous thread. The at least one thread may comprise a plurality of threads. At least two of the plurality of threads may be entwined to form a rope or rope-like structure. Advantageously, this may make the at least one thread stronger. Alternatively, or in addition, the rope or rope-like structure may be thicker than the thread alone, so may create larger spaces for airflow or aerosol generation, as explained in more detail later.

[0033] At least a first thread of the plurality of threads may be attached to at least a second thread of the plurality of threads. This may advantageously increase a length of the at least one thread.

[0034] The at least one thread may comprise or consist of one or more natural fibers. The at least one thread may comprise or consist of one or more synthetic fibers. The at least one thread may comprise or consist of any one or more of: cotton, silk, wool, jute, ramie, hemp, linen, rayon, polyester, and nylon.

[0035] The at least one thread may comprise or be soaked or impregnated with 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. This may advantageously be an easy way to incorporate flavours into the article.

[0036] The at least one thread may comprise or be soaked or impregnated with one or more aerosol formers such as glycerine or propylene glycol. This may advantageously aid aerosol formation during use.

[0037] The at least one thread may comprise one or more susceptor materials. The at least one thread may hold one or more susceptor materials. One or more susceptor materials may be attached to or coated on the at least one thread. Suitable susceptor materials may be materials configured to heat up, for example to at least 50, 100 or 200 degrees Celsius, when subjected to an alternating electromagnetic field. Suitable susceptor materials include but are not limited to: carbon, carbon-based materials, graphene, graphite, expanded graphite, molybdenum, silicon carbide, stainless steels, niobium, aluminium, nickel, nickel- containing compounds, titanium, and composites of metallic materials. Suitable susceptor materials may comprise a ferromagnetic material, for example, ferritic iron, a ferromagnetic alloy, such as ferromagnetic steel or stainless steel, ferromagnetic particles, and ferrite. A suitable susceptor material may be, or comprise, aluminium. A susceptor material preferably comprises more than 5 percent, preferably more than 20 percent, more preferably more than 50 percent or more than 90 percent of ferromagnetic or paramagnetic materials. Preferred susceptor materials may comprise a metal, metal alloy or carbon. This may advantageously allow the at least one thread to aid heating of the substrate, optionally in multiple places in or around the substrate, for example when the substrate is configured to be inductively heated.

[0038] Optionally, the aerosol-forming substrate is not sewn to any other component of the aerosolgenerating article. Optionally, the aerosol-forming substrate is sewn to itself. Optionally, the aerosol-forming substrate is sewn to itself and no other component of the aerosol-generating article. This may be advantageous if the substrate is intended to moved independently of the other components of the article, for example where a user places the substrate in the article themselves when they wish to use the article.

[0039] Optionally, the aerosol-forming substrate is sewn with the at least one thread to at least one other component of the aerosol-generating article. Advantageously, this may mean that the at least one thread secures the substrate in position relative to the at least one other component of the aerosol-generating article.

[0040] Optionally, the aerosol-generating article comprises a first cover. The first cover may comprise or be formed of paper such as cigarette paper. Optionally, the first cover covers a first surface, or at least 50, 80 or 90 percent of the first surface, of the aerosol-forming substrate. Optionally, the first cover contacts the aerosol-forming substrate. Optionally, the first cover contacts the first surface, or at least 50, 80 or 90 percent of the first surface, of the aerosol-forming substrate. The first surface may be or comprise the upper surface of the aerosol-forming substrate. Optionally, the first cover covers a second surface, or at least 50, 80 or 90 percent of the second surface, of the aerosol-forming substrate. Optionally, the first cover contacts the second surface, or at least 50, 80 or 90 percent of the second surface, of the aerosol-forming substrate. The second surface may be or comprise the lower surface of the aerosol-forming substrate. The first cover may cover both the upper surface and the lower surface, for example by extending across the upper surface, then across a side of the substrate, then across the lower surface. The first cover may wrap around a side of the substrate between the upper surface and the lower surface. Advantageously, the first cover may protect the aerosol-forming substrate. Advantageously, the first cover may reduce a risk of contamination of the aerosol-forming substrate with dust or the like.

[0041] Optionally, the aerosol-forming substrate is sewn with the at least one thread to the cover. Advantageously, this may secure the substrate in position relative to the cover.

[0042] Optionally, at least a portion of the first cover is located between a portion of the at least one thread and the aerosol-forming substrate such as the upper or lower surface of the substrate. Optionally, at least a portion of the first cover is located between a portion of the at least one thread extending along the substrate in the first along direction and the aerosol-forming substrate. Optionally, at least a portion of the first cover is located between a portion of the at least one thread extending along the substrate in the second along direction and the aerosol-forming substrate. The at least one thread may be in contact with the first cover as the at least one thread extends along the substrate. The at least one thread may be in contact with the first cover as the at least one thread extends along the substrate in one or both of the first along direction and the second along direction.

[0043] Optionally, at least a portion of the at least one thread extends through the first cover in the first through direction. The at least one thread may then extend through the substrate in the first through direction. The at least one thread may then extend through the first cover in the first through direction. The at least one thread may then extend along the first cover in a first along direction. The at least one thread may then extend through the first cover in the second through direction. The at least one thread may then extend through the substrate in the second through direction, optionally substantially opposing the first through direction. The at least one thread may then extend through the first cover in the second through direction. The at least one thread may then extend along the first cover in a second along direction, optionally substantially the same as the first along direction.

[0044] Optionally, the aerosol-generating article comprises the first cover and a second cover. The second cover may comprise or be formed of paper. Optionally, the second cover contacts the aerosol-forming substrate. Optionally, the first cover covers the first surface, or at least 50, 80 or 90 percent of the first surface, of the aerosol-forming substrate and the second cover covers the second surface, or at least 50, 80 or 90 percent of the second surface, of the aerosol-forming substrate. Optionally, the first cover contacts the first surface, or at least 50, 80 or 90 percent of the first surface, of the aerosol-forming substrate and the second cover contacts the second surface, or at least 50, 80 or 90 percent of the second surface, of the aerosol-forming substrate. Optionally, the cover is located on a substantially opposite side of the aerosol-forming substrate to the second cover. The first surface may be or comprise the upper surface of the aerosol-forming substrate and the second surface may be or comprise the lower surface of the aerosolforming substrate, or vice versa. The first cover and the second cover may effectively sandwich the aerosolforming substrate. Advantageously, the first and second covers may protect the aerosol-forming substrate. Advantageously, the first and second covers may reduce a risk of contamination of the aerosol-forming substrate with dust or the like.

[0045] Optionally, the aerosol-forming substrate is sewn with the at least one thread to the first cover and the second cover. Advantageously, this may secure the substrate in position relative to the first and second covers. Optionally, at least a portion of the second cover is located between a portion of the at least one thread and the aerosol-forming substrate such as the upper or lower surface of the substrate. Where at least a portion of the first cover is located between a portion of the at least one thread and an upper or lower surface of the aerosol-forming substrate, at least a portion of the second cover may be located between another portion of the at least one thread and the other of the upper or lower surface of the substrate. Optionally, at least a portion of the second cover is located between a portion of the at least one thread extending along the substrate in the second along direction and the aerosol-forming substrate.

[0046] Optionally, at least a portion of the at least one thread extends through the first cover in the first through direction. The at least one thread may then extend through the substrate in the first through direction. The at least one thread may then extend through the second cover in the first through direction. The at least one thread may then extend along the second cover in a first along direction. The at least one thread may then extend through the second cover in the second through direction. The at least one thread may then extend through the substrate in the second through direction, optionally substantially opposing the first through direction. The at least one thread may then extend through the first cover in the second through direction. The at least one thread may then extend along the first cover in a second along direction, optionally substantially the same as the first along direction.

[0047] Optionally, at least a portion of the first cover is located between a portion of the at least one thread and the aerosol-forming substrate, and at least a portion of the second cover is located between another portion of the at least one thread and the aerosol-forming substrate. Optionally, at least a portion of the first cover is located between a portion of the at least one thread extending along the substrate in the second along direction and the aerosol-forming substrate. Optionally, at least a portion of the second cover is located between a portion of the at least one thread extending along the substrate in the first along direction and the aerosol-forming substrate. The at least one thread may be in contact with the first cover as the at least one thread extends along the substrate in the second along direction. The at least one thread may be in contact with the second cover as the at least one thread extends along the substrate in the first along direction.

[0048] Optionally, the first cover and the second cover are at least part of a wrapper, the wrapper optionally encircling the aerosol-forming substrate or circling around at least 180, 270 or 315 degrees of the aerosolforming substrate. The wrapper may be a unitary component, such as the first cover alone. The wrapper may comprise multiple components, such as the first and second covers described above.

[0049] A portion of the aerosol-forming substrate may be exposed. A portion of the aerosol-forming substrate may not be covered, for example may not be covered by the first cover orthe second cover where present. One or more sides, for example one or both sides of the substrate defined by the substrate length and substrate thickness, may be exposed. One or more sides, for example one or both sides of the substrate defined by the substrate length and substrate thickness, may not be covered, for example may not be covered by the first cover or the second cover where present. One or more sides, for example one or both sides of the substrate defined by the substrate width and substrate thickness, may be exposed. One or more sides, for example one or both sides of the substrate defined by the substrate width and substrate thickness, may not be covered, for example may not be covered by the first cover or the second cover where present. Optionally, the aerosol-forming substrate is a multi-layer aerosol-forming substrate. Optionally, the aerosol-forming substrate comprises a first layer of aerosol-forming material. Optionally, the aerosolforming substrate comprises a second layer of aerosol-forming material. Optionally, the first layer of aerosol-forming material may be a sheet of aerosol-forming material, for example a sheet of tobaccocontaining material such as a sheet of homogenised tobacco-containing material. Optionally, the second layer of aerosol-forming material may be a sheet of aerosol-forming material, for example a sheet of tobacco-containing material such as a sheet of homogenised tobacco-containing material. One or each of the first and second layers of aerosol-forming material may be formed by a cast leaf process. The first and second layers of aerosol-forming material may have identical or different compositions. The first layer or sheet may be crimped. The second layer or sheet may be crimped. In this context, the term “crimped” may mean that the layer or sheet has a plurality of ridges or corrugations, optionally a plurality of substantially parallel ridges or corrugations.

[0050] Optionally, the first layer of aerosol-forming material has a first layer length, a first layer width, and a first layer thickness. The first layer length, the first layer width and the first layer thickness may extend in mutually perpendicular directions. The first layer length may extend in a first layer length direction, for example the substrate length direction. The first layer width may extend in a first layer width direction, for example the substrate width direction. The first layer thickness may extend in a first layer length thickness, for example the substrate thickness direction. The first layer length and the first layer width may be at least 2, 3, or 5 times the first layer thickness.

[0051] Optionally, the second layer of aerosol-forming material has a second layer length, a second layer width, and a second layer thickness. The second layer length, the second layer width and the second layer thickness may extend in mutually perpendicular directions. The second layer length may extend in a second layer length direction, for example the substrate length direction. The second layer width may extend in a second layer width direction, for example the substrate width direction. The second layer thickness may extend in a second layer length thickness, for example the substrate thickness direction. The second layer length and the second layer width may be at least 2, 3 or 5 times the second layer thickness.

[0052] Optionally, the first layer of aerosol-forming material is sewn with the at least one thread, for example with at least one first thread. Optionally, the first layer of aerosol-forming material is sewn to itself and no other component of the article with the at least one thread for example the at least one first thread. This may create dimples or ridges or both in the first layer. Optionally, the second layer of aerosol-forming material is sewn with at least one thread, for example with at least one second thread. Optionally, the second layer of aerosol-forming material is sewn to itself and no other component of the article with the at least one thread or at least one second thread. This may create dimples or ridges or both in the second layer. Advantageously, the dimples and ridges may create a three-dimensional structure for airflow and aerosol generating adjacent to or between the layers.

[0053] Optionally, at least a first portion of the at least one thread or at least one first thread is located between the first layer of aerosol-forming material and the second layer of aerosol-forming material. Optionally, at least a second portion of the at least one thread or at least one second thread is located between the first layer of aerosol-forming material and the second layer of aerosol-forming material. Advantageously, this may provide a space for airflow and aerosol generating between the layers. Optionally, the first layer of aerosol-forming material has a first surface, optionally defined by the first layer length and the first layer width. Optionally, the second layer of aerosol-forming material has a second surface, optionally defined by the second layer length and the second layer width.

[0054] Optionally, at least the first portion of the at least one thread or at least one first thread is located between the first surface of the first layer of aerosol-forming material and the second surface of the second layer of aerosol-forming material. Optionally, at least the first portion of the at least one thread or at least one first thread extends along one or both of the first surface of the first layer of aerosol-forming material and the second surface of the second layer of aerosol-forming material. Optionally, at least the first portion of the at least one thread or at least one first thread is in contact with one or both of the first surface of the first layer of aerosol-forming material and the second surface of the second layer of aerosol-forming material, for example as at least the first portion of the at least one thread or at least one first thread extends along one or both of the first surface of the first layer of aerosol-forming material and the second surface of the second layer of aerosol-forming material.

[0055] Optionally, at least the second portion of the at least one thread or at least one second thread is located between the first surface of the first layer of aerosol-forming material and the second surface of the second layer of aerosol-forming material. Optionally, at least the second portion of the at least one thread or at least one second thread extends along one or both of the first surface of the first layer of aerosolforming material and the second surface of the second layer of aerosol-forming material. Optionally, at least the second portion of the at least one thread or at least one second thread is in contact with one or both of the first surface of the first layer of aerosol-forming material and the second surface of the second layer of aerosol-forming material, for example as at least the second portion of the at least one thread or at least one second thread extends along one or both of the first surface of the first layer of aerosol-forming material and the second surface of the second layer of aerosol-forming material.

[0056] Optionally, at least the first portion of the at least one thread or at least one first thread acts as a spacer between the first layer of aerosol-forming material and the second layer of aerosol-forming material, for example between the first surface of the first layer of aerosol-forming material and the second surface of the second layer of aerosol-forming material. Optionally, at least the second portion of the at least one thread or at least one second thread acts as a spacer between the first layer of aerosol-forming material and the second layer of aerosol-forming material, for example between the first surface of the first layer of aerosol-forming material and the second surface of the second layer of aerosol-forming material.

[0057] Optionally, the aerosol-generating article defines at least a portion of an air flow path between the first layer of aerosol-forming material and the second layer of aerosol-forming material, for example between the first surface of the first layer of aerosol-forming material and the second surface of the second layer of aerosol-forming material.

[0058] Advantageously, as set out in the above few paragraphs, the at least one thread may act as a spacer between the first and second layers of the substrate. This may advantageously provide space for airflow or aerosol generation between the layers.

[0059] The at least one thread may comprise the at least one first thread. The at least one thread may comprise the at least one thread or at least one second thread.

[0060] The at least one thread or first thread may extend through the first layer of aerosol-forming material, for example in the first through direction. The at least one thread or first thread may then extend along the first layer of aerosol-forming material, optionally along the first surface of the first layer of aerosol-forming material and optionally in the first along direction. The at least one thread or first thread may then extend through the first layer of aerosol-forming material, for example in the second through direction. The at least one thread or first thread may then extend along the first layer of aerosol-forming material, optionally along a second surface of the first layer of aerosol-forming material and optionally in the first along direction.

[0061] When extending through the first layer, the at least one thread or at least one first thread may extend through a thickness of the first layer. When extending along the first layer, the at least one thread or at least one first thread may extend in a direction perpendicular to the first layer thickness direction, for example in one or both of the first layer length and width directions. In this context and in similar contexts, a direction extending in both a length and width direction means that the direction has both a length and width component.

[0062] The at least one second thread may extend through the second layer of aerosol-forming material, for example in the second through direction. The at least one second thread may then extend along the second layer of aerosol-forming material, optionally along the second surface of the second layer of aerosol-forming material and optionally in the first along direction. The at least one second thread may then extend through the second layer of aerosol-forming material, for example in the first through direction. The at least one second thread may then extend along the second layer of aerosol-forming material, optionally along a first surface of the second layer of aerosol-forming material and optionally in the first along direction.

[0063] When extending through the second layer, the at least one thread or at least one second thread may extend through a thickness of the second layer. When extending along the second layer, the at least one thread or at least one second thread may extend in a direction perpendicular to the second layer thickness direction, for example in one or both of the second layer length and width directions.

[0064] The at least one thread or first thread may extend through the first layer, along and optionally in contact with the first surface of the first layer, back through the first layer, then along and optionally in contact with the second surface of the first layer. The at least one thread or first thread may then repeat this. Similarly, the at least one thread or at least one second thread may extend through the second layer, along and optionally in contact with the second surface of the second layer, back through the second layer, then along and optionally in contact with the first surface of the second layer. The at least one second thread may then repeat this.

[0065] The extension of the at least one thread or at least one first thread along the first surface of the first layer may any one, two or all of: be located between the first surface of the first layer and the second surface of the second layer; be in contact with one or both of the first surface of the first layer and the second surface of the second layer; and act as a spacer between the first surface of the first layer and the second surface of the second layer, for example at least at its specific location.

[0066] The extension of the at least one thread or at least one second thread along the second surface of the second layer may any one, two or all of: be located between the first surface of the first layer and the second surface of the second layer; be in contact with one or both of the first surface of the first layer and the second surface of the second layer; and act as a spacer between the first surface of the first layer and the second surface of the second layer, for example at least at its specific location. Advantageously, having the first layer sewn with the at least one thread or at least one first thread and the second layer sewn with the at least one thread or at least one second thread may create more spacing between the layers for airflow and aerosol generation.

[0067] The at least one thread may comprise at least one combining thread. The first layer of aerosolforming material may be sewn to the second layer of aerosol-forming material by at least one combining thread. The at least one combining thread may extend through the first layer of aerosol-forming material and the second layer of aerosol-forming material, for example in one or both of the first through direction and the second through direction.

[0068] The aerosol-forming substrate may comprise at least two, three, or five layers of aerosol-forming material. Each layer may have identical or different compositions. Each layer may be sewn with at least one thread, for example with the at least one thread. There may be n layers. The nth layer may be sewn with at least one nth thread. In other words, the first layer may be sewn with at least one first thread, the second layer may be sewn with at least one second thread, and so on, optionally as described above in relation to first and second layers of the substrate being sewn with the at least one first thread and the at least one second thread, respectively. Thus, features described above in relation to the sewing of the first layer with the at least one first thread, or sewing of the second layer with the at least one second thread, may equally apply to sewing the nth layer with the at least one nth thread. Similarly, features described in relation to a thread being located at least partly between the first and second layers may apply to between other adjacent layers, such as between the second and third layers, or the third and fourth layers. Each of the layers may be sewn with at least one combining thread. The at least one combining thread may sew the layers together, for example as described above in relation to sewing together the first and second layers of the substrate.

[0069] Advantageously, sewing each layer with at least one thread may introduce dimples or ridges for airflow or aerosol generation between the layers. Advantageously, the thread may also, at least partly, be located between the layers and thus act to provide one or more spaces between the layers for airflow or aerosol generation. Advantageously, sewing the layers together, for example with at least one combining thread, may secure the layers of the substrate together easily and reliably. Advantageously, sewing is compatible with linear, high-speed processes.

[0070] The length, width and thickness of each layer of the substrate may align with the length, width and thickness of the substrate, respectively. In this case, the direction of any thread through a thickness of a layer of the substrate may align, or be parallel with, a direction through a thickness of the substrate.

[0071] Alternatively, the length, width and thickness of each layer of the substrate may not align with the length, width and thickness of the substrate, respectively. For example, after sewing the layers together, the resulting sewn substrate may be considered to have a substrate thickness, extending in a substrate thickness direction, that aligns or is parallel with a or each layer length direction, or with a or each layer width direction. This arrangement may advantageously allow creation of air flow passages through the substrate in a different orientation compared with if each layer of the substrate aligned with the length, width and thickness of the substrate, respectively.

[0072] The aerosol-generating article may have an air flow path extending through the aerosol-generating article. The aerosol-generating article may have an air flow path defined through the aerosol-generating article in an x / y plane from one side of the aerosol-generating article to the other side of the aerosol- generating article. The aerosol-generating article preferably has a resistance to draw (RTD) of less than 20 millimetre H2O, for example less than 10 millimetre H2O, in the direction of the airflow path. Preferably, the aerosol-generating article has a RTD of less than 20 millimetre H2O, for example less than 10 millimetre H2O, in at least one direction in an x / y plane of the aerosol-generating article. An aerosol-generating article with a low resistance air-flow path may allow for superior air-flow management and allow aerosol to be extracted more efficiently from the aerosol-generating article and guided to a user.

[0073] 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%.

[0074] The aerosol-generating article 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 aerosol-forming material. 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 material.

[0075] The aerosol-generating article may comprise a corrugated element, for example arranged between the first or upper layer and the second or lower layer. At least one of the first layer, the planar layer and the corrugated element may comprise or consist of aerosol-forming material.

[0076] 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.

[0077] The aerosol-generating article may comprise a first external surface, a second external surface, a cavity and a frame. One or both of the first and second external surfaces may be planar. The frame may be positioned between the first external surface and the second external surface. The frame may at least partially define the cavity. 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.

[0078] Preferably, the aerosol-forming substrate is positioned between the first external surface and the second external surface. The at least one thread may be positioned entirely between the first external surface and the second external surface. The first cover and, if present, the second cover may be positioned between the first external surface and the second external surface.

[0079] Alternatively, the first external surface may be a surface of the first cover. The second external surface may be a surface of the second cover.

[0080] 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.

[0081] The aerosol-generating article may comprise a first external layer and a second external layer, in which the first external layer forms the first external surface and the second external layer forms the second external surface. The first cover may comprise the first and second external layers. Alternatively, the first cover may comprise or be the first external layer and the second cover may comprise or may the second external layer. 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 material.

[0082] The cavity may be substantially empty. The aerosol-forming substrate may be positioned outside the cavity. Alternatively, the aerosol-forming substrate may be positioned within the cavity. The corrugated element may be positioned within the cavity.

[0083] The frame may be a planar frame. The frame may have a height between 50 percent and 95 percent of the height of the aerosol-generating 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.

[0084] 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.

[0085] The frame may be made from or comprise a biodegradable material. The frame may be made entirely from a biodegradable material.

[0086] 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.

[0087] 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.

[0088] The article length may be 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.

[0089] The article width may be between 5 millimetres and 20 millimetres, for example between 8 millimetres and 18 millimetres, for example between 10 millimetres and 16 millimetres, for example between 11 millimetres and 15 millimetres, for example between 12 millimetres and 14 millimetres, for example about

[0090] 13 millimetres.

[0091] The article height may be 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

[0092] 1 .6 millimetres and 6 millimetres, for example between 1 .7 millimetres and 5 millimetres, for example about

[0093] 1 .7 millimetres, or about 4.5 millimetres, or about 2 millimetres, or about 3 millimetres, or about 4 millimetres.

[0094] The aerosol-generating article 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 aerosol-generating article comprises substantially planar upper and lower surfaces, a perimeter of one or both of the upper and lower surfaces when viewed in plan may have a shape defining a polygon, a quadrilateral (for example, a rectangle or a square), an oval, a circle, or a combination thereof.

[0095] The aerosol-forming substrate may be or comprise a plug of aerosol-forming substrate.

[0096] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, may comprise nicotine. Nicotine may be present in the form of a tobacco material or may be in the form of a nicotine extract. The aerosol-forming substrate, for example one or both of the first and second layers of aerosol-forming material where present, may comprise natural nicotine, or synthetic nicotine, or a combination of natural nicotine and synthetic nicotine.

[0097] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, may comprise one or more organic materials such as tobacco, mint, tea and cloves. The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, 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.

[0098] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, may comprise or consist of homogenised tobacco material, for example a reconstituted tobacco material or a cast leaf tobacco material.

[0099] 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.

[0100] The aerosol-forming substrate may be or comprise cut filler. The aerosol-forming substrate may be or comprise 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.

[0101] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, 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.

[0102] 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.

[0103] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, 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.

[0104] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, 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, for example one or both of the first and second layers of aerosol-forming material where present, may have an aerosol-former 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.

[0105] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, 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.

[0106] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, 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.

[0107] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, 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.

[0108] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, 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.

[0109] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, 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.

[0110] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, 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.

[0111] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, 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.

[0112] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, may comprise one or more botanicals. For example, the aerosol-forming 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.

[0113] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, 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, for example one or both of the first and second layers of aerosol-forming material where present, may be a homogenised tobacco material with a moisture of about 5 to 25%, preferably of about 7 to 15%, at final product state.

[0114] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, 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, ethyl hydroxymethyl and carboxymethyl, celluloses; dextran; and xanthan gum. A preferable binder is guar.

[0115] The aerosol-forming substrate, for example one or both of the first and second layers of aerosolforming material where present, may comprise, or consist of, a solid aerosol-forming material. The aerosolforming substrate, for example one or both of the first and second layers of aerosol-forming material where present, may comprise a liquid aerosol-forming material, for example a liquid aerosol-forming material retained within a porous matrix. The aerosol-forming substrate, for example one or both of the first and second layers of aerosol-forming material where present, may comprise a gel aerosol-forming material.

[0116] According to the present disclosure, there is provided an aerosol-generating device. The device may be for receiving an aerosol-generating article as disclosed herein, or an aerosol-forming substrate as disclosed herein, and may comprise a cavity dimensioned to receive at least a portion of the aerosolgenerating 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 may be 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] According to the present disclosure, there is provided an aerosol-generating system comprising an aerosol-generating device, such as the aerosol-generating device described above, and the aerosolgenerating article described above.

[0121] According to the present disclosure, there is provided a method of making an aerosol-generating article as described above. The method comprises sewing at least a portion of the aerosol-forming substrate with at least one thread.

[0122] Optionally, the method comprises sewing the aerosol-forming substrate with at least one thread so as to hold the aerosol-forming substrate in a compressed state. Optionally, the method comprises sewing the aerosol-forming substrate with at least one thread so as to limit expansion of the aerosol-forming substrate. Optionally, the method comprises providing a rod, the rod comprising or consisting of aerosol-forming substrate material. Optionally, the method comprises compressing the rod to form a compressed rod comprising the aerosol-forming substrate in a first compressed state. Optionally, the method comprises sewing the aerosol-forming substrate with the at least one thread, for example so as to hold the aerosolforming substrate in a second compressed state, the second compressed state optionally being a compressed state in the substrate thickness direction.

[0123] Optionally, the method comprises providing a rod, the rod comprising aerosol-forming substrate material and a wrapper encircling the aerosol-forming substrate material. The rod may initially be substantially cylindrical, for example right circular cylindrical, in shape. Optionally, the method comprises compressing the rod to form a compressed rod comprising the aerosol-forming substrate in a first compressed state. Optionally, the method comprises sewing the aerosol-forming substrate with the at least one thread to the wrapper so as to hold the aerosol-forming substrate in a second compressed state, the second compressed state optionally being a compressed state in the substrate thickness direction. Optionally, the method comprises cutting the wrapper. The wrapper may form or comprise one or both of the first cover and the second cover described earlier. Optionally, the method comprises cutting the wrapper to provide an aerosol-forming substrate with the first cover as described earlier, or with the first and second covers as described earlier.

[0124] With reference to the above two paragraphs, the rod, before being compressed, may be substantially cylindrical, for example right circular cylindrical, in shape. Compressing the rod may comprise compressing the rod between two surfaces, for example between two rollers or between a roller and a stationary surface. The compressed rod may be cylindrical or prismatic in shape. The compressed rod may have a substantially oval or rectangular, optionally with somewhat rounded corners, transverse cross-section. A shortest dimension of the compressed rod through a centroid of its transverse cross-section may be considered the substrate thickness. Thus, for a rectangular cross-section, the substrate thickness may be equal to the smaller dimension of the rectangular cross-section, and for an oval cross-section, the substrate thickness may be equal to the minor axis of the oval cross-section.

[0125] With reference to the above three paragraphs, the second compressed state may be more, equally, or less compressed than the first compressed state. For example, sewing the substrate could compress the substrate further, meaning that the second compressed state is more compressed than the first compressed state. Or the substrate could expand a little between being compressed and being sewn, meaning that the second compressed state is less compressed than the first compressed state. Or both, or neither, which could mean that the second compressed state is substantially equally compressed compared with the first compressed state. As the skilled person would understand after reading this disclosure, features described above in relation to a compressed state of the substrate, or in relation to a state from which expansion is limited or restricted, may apply to these first and second compressed states.

[0126] Optionally, the aerosol-forming substrate is a multi-layer substrate. Optionally, the aerosol-forming substrate comprises a first layer of aerosol-forming material and a second layer of aerosol-forming material, for example as described earlier. In this case, the method may comprise sewing the first layer of aerosolforming material of the aerosol-forming substrate with at least one first thread. The first layer of aerosolforming material may be sewn with at least one first thread to no other component of the article. The first layer of aerosol-forming material may be sewn, with at least one first thread, to itself only. Optionally, the method comprises sewing the second layer of aerosol-forming material the aerosol-forming substrate with at least one second thread. The second layer of aerosol-forming material may be sewn, with at least one second thread to no other component of the article. The second layer of aerosol-forming material may be sewn, with at least one second thread, to itself only. Optionally, the method comprises sewing the first layer of aerosol-forming material to the second layer of aerosol-forming material with at least one combining thread.

[0127] The aerosol-forming substrate may comprise at least two, three, or five layers of aerosol-forming material. Each layer may have identical or different compositions. Each layer may be sewn with at least one thread. There may be n layers. The nth layer may be sewn with at least one nth thread. In other words, the first layer may be sewn with at least one first thread, the second layer may be sewn with at least one second thread, and so on. Each of the layers may be sewing with at least one combining thread. The at least one combining thread may sew the layers together.

[0128] Advantageously, sewing each layer with at least one thread may introduce dimples or ridges for airflow or aerosol generation between the layers. Advantageously, sewing the layers together may secure the layers of the substrate together easily and reliably. Advantageously, sewing is compatible with linear, high-speed processes.

[0129] The aerosol-forming substrate, for example of the first aspect, may comprise a plurality of aerosolgenerating elements, for example an array of aerosol-generating elements. The at least one thread may link, or sew together, the aerosol-generating elements. The provision of an aerosol-forming substrate in the form of a plurality of elements may advantageously provide a substrate with a desirable surface to volume ratio, which optimises release of aerosol from the substrate upon heating.

[0130] The plurality of aerosol-generating elements optionally comprises a first set of aerosol-generating elements opposing a second set of aerosol-generating elements. At least one air flow passage may be defined between at least one air inlet and at least one air outlet of the article. Optionally, at least a portion of at least one airflow passage is defined between the first and second sets of aerosol-generating elements. Advantageously, this may lead to a predictable and controlled resistance to draw.

[0131] At least one, preferably each, of the plurality of aerosol-generating elements of the preceding paragraph may be substantially planar. Optionally, at least one, preferably each one, of aerosol-generating elements has a length of between 1 millimetre and 30 millimetres, preferably between 2 and 10 millimetres. Optionally, at least one, preferably each one, of aerosol-generating elements has a width of between 1 millimetre and 30 millimetres, preferably between 2 and 10 millimetres. Optionally, at least one, preferably each one, of aerosol-generating elements has a thickness of between 50 and 500 microns.

[0132] Optionally, the first set of aerosol-generating elements are arranged in a regular pattern, for example a grid-like pattern. Optionally, the second set of aerosol-generating elements are arranged in a regular pattern, for example a grid-like pattern. Optionally, the array of aerosol-generating elements is arranged in a regular pattern. Optionally, at least one of aerosol-generating elements partially overlaps with another of the aerosol-generating elements. This may advantageously facilitate incorporating a given number of elements within a predefined volume. The provision of an aerosol-forming substrate in the form of an array may allow the position of the substrate within the article to be predictable, which may lead to more consistent experiences between different articles. Optionally, the first type aerosol-generating element and the second type aerosol-generating element are provided in an alternating pattern. Advantageously, this may mean that the types of element are not overly separated and that aerosol generated from the types of element mixes well before delivery.

[0133] Optionally, the aerosol-generating elements comprises a first type of aerosol-generating element and a second type of aerosol-generating element, different from the first type. Optionally, the second type of aerosol-generating element differs from the first type of aerosol-generating element by at least one of: type of aerosol-forming material, amount of aerosol-forming material, type of aerosol-former, amount of aerosolformer, type of flavourant, amount of flavourant, shape, or size. Advantageously, this may provide an easy way to provide different compositions in an article.

[0134] Optionally, the at least one thread passes through at least one aerosol-generating element. Optionally, the at least one thread passes through each of the aerosol-generating elements. Optionally, the article comprises a carrier sheet for carrying the aerosol-generating elements. Optionally, the article comprises an adhesive that adheres at least two aerosol-generating elements to the carrier sheet. Optionally, the aerosol-generating elements are connected to the carrier sheet by the at least one thread passing through each of the aerosol-generating elements. Advantageously, these features may help secure the aerosol-generating elements in place in an article.

[0135] Optionally, the carrier sheet is fluid permeable to allow air and aerosol through the carrier sheet. Optionally, the carrier sheet is formed of or comprises cotton. Optionally, the carrier sheet is or comprises a woven fabric. Advantageously, this may enhance air flow in the article.

[0136] As used herein, the term “aerosol-generating article” may refer to an article able to generate, or release, an aerosol.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] As used herein, the term “nicotine”, is used to describe nicotine, nicotine base or a nicotine salt.

[0142] As used herein, 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, for example during use. 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.

[0143] As used herein, the term “sheet” denotes a laminar element having a width and length substantially greater than the thickness thereof. The width of a sheet may be greater than 10 mm, preferably greater than 20 mm or 30 mm. In certain embodiments, sheets of material for use in forming aerosol-forming substrates as described herein may have a thickness of between 10 pm and about 1000 pm, for example between 10 pm and about 300 pm.

[0144] 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.

[0145] 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.

[0146] 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.

[0147] 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.

[0148] Example Ex1 . An aerosol-generating article comprising: an aerosol-forming substrate; and at least one thread, wherein at least a portion of the aerosol-forming substrate is sewn with the at least one thread.

[0149] Example Ex2. An aerosol-generating article according to any preceding example, wherein the aerosolgenerating article has an article length, an article width, and an article thickness, the article length being at least 2, 3 or 5 times the article thickness and the article width being at least 2, 3 or 5 times the article thickness.

[0150] Example Ex3. An aerosol-generating article according to any preceding example, wherein the aerosolforming substrate has a substrate length, a substrate width, and a substrate thickness, the substrate length being at least 2, 3 or 5 times the substrate thickness and the substrate width being at least 2, 3 or 5 times the substrate thickness.

[0151] Example Ex4. An aerosol-generating article according to any preceding example, wherein the aerosolforming substrate is sewn with the at least one thread to hold the aerosol-forming substrate in a compressed state, for example in a compressed state relative to a natural state of the aerosolforming substrate.

[0152] Example Ex5. An aerosol-generating article according to any preceding example, wherein the aerosolforming substrate is sewn with the at least one thread to limit expansion of the aerosol-forming substrate.

[0153] Example Ex6. An aerosol-generating article according to any preceding example, wherein the at least one thread is under tension, for example due to the aerosol-forming substrate acting to expand.

[0154] Example Ex7. An aerosol-generating article according to any preceding example, wherein the aerosolforming substrate sewn with the at least one thread occupies a first volume and, if the at least one thread were removed, the aerosol-forming substrate would expand to occupy a second volume greater than the first volume.

[0155] Example Ex8. An aerosol-generating article according to any preceding example, wherein at least a portion of the at least one thread extends: through the substrate in a first through direction; then, optionally immediately, along the substrate in a first along direction; then, optionally immediately, through the substrate in a second through direction, optionally substantially opposing the first through direction; then, optionally immediately, along the substrate in a second along direction, optionally substantially the same as the first along direction.

[0156] Example Ex9. An aerosol-generating article according to example Ex8, wherein the aerosol-forming substrate has a substrate length extending in a substrate length direction, a substrate width extending in a substrate width direction and a substrate thickness extending in a substrate thickness direction, optionally wherein any one or more of the following is true: the substrate length is greater, for example at least 2, 3 or 5 times greater, than the substrate thickness; the substrate width is greater, for example at least 2, 3 or 5 times greater, than the substrate thickness; and the substrate length is greater, for example at least 2, 3 or 5 times greater, than the substrate width.

[0157] Example Ex10. An aerosol-generating article according to example Ex9, wherein one or both of: the first through direction is non-perpendicular to the substrate thickness direction, for example wherein the first through direction is substantially parallel to the substrate thickness direction; and the second through direction is non-perpendicular to the substrate thickness direction, for example wherein the second through direction is substantially parallel to the substrate thickness direction.

[0158] Example Ex11 . An aerosol-generating article according to example Ex9 or Ex10, wherein one or both of: the first along direction is non-perpendicular with one or both of the substrate length direction and the substrate width direction; and the second along direction is non-perpendicular with one or both of the substrate length direction and the substrate width direction.

[0159] Example Ex12. An aerosol-generating article according to example Ex11 , wherein one or both of: the first along direction is non-perpendicular with the substrate length direction, for example wherein the first along direction is substantially parallel with the substrate length direction; and the second along direction is non-perpendicular with the substrate length direction, for example wherein the second along direction is substantially parallel with the substrate length direction, for example where the at least one thread forms a linear stitching pattern along the aerosolforming substrate in the substrate length direction.

[0160] Example Ex13. An aerosol-generating article according to example Ex11 , wherein one or both of: the first along direction is non-perpendicular with the substrate width direction, for example wherein the first along direction is substantially parallel with the substrate width direction; and the second along direction is non-perpendicular with the substrate width direction, for example wherein the second along direction is substantially parallel with the substrate width direction, for example where the at least one thread forms a linear stitching pattern along the aerosolforming substrate in the substrate width direction.

[0161] Example Ex14. An aerosol-generating article according to example Ex11 , wherein one or both of: the first along direction is non-perpendicular with the substrate length direction and non- perpendicular with the substrate width direction; and the second along direction is non-perpendicular with the substrate length direction and non-perpendicular with the substrate width direction, for example where the at least one thread forms a zig-zag stitching pattern along the aerosol-forming substrate.

[0162] Example Ex15. An aerosol-generating article according to any of examples Ex8 to Ex14, wherein the at least one thread extends into the substrate in the first through direction at a first location and extends out of the substrate in the second through direction at a second location, and wherein a distance between the first location and the second location is no more than 10, 5 or 3 millimetres.

[0163] Example Ex16. An aerosol-generating article according to any preceding example, wherein the at least one thread extends through the aerosol-forming substrate at least 5, 10 or 20 times.

[0164] Example Ex17. An aerosol-generating article according to any preceding example, wherein a ratio of a substrate length of the aerosol-forming substrate to a thread length of the at least one thread is between 1 :1 .5 and 1 :50, or between 1 :2 and 1 :20, or between 1 :2 and 1 :10. Example Ex18. An aerosol-generating article according to any preceding example, wherein the aerosolforming substrate is not sewn to any other component of the aerosol-generating article.

[0165] Example Ex19. An aerosol-generating article according to any preceding example, wherein the aerosolforming substrate is sewn with the at least one thread to at least one other component of the aerosol-generating article.

[0166] Example Ex20. An aerosol-generating article according to any preceding example, wherein the aerosolgenerating article comprises a cover, for example a paper cover.

[0167] Example Ex21 . An aerosol-generating article according to example Ex20, wherein the aerosol-forming substrate is sewn with the at least one thread to the cover.

[0168] Example Ex22. An aerosol-generating article according to example Ex20 or Ex21 , wherein the cover covers a first surface, or at least 50, 80 or 90 percent of the first surface, of the aerosol-forming substrate.

[0169] Example Ex23. An aerosol-generating article according to example Ex22, wherein at least a portion of the cover is located between a portion of the at least one thread extending along the substrate in the first along direction and the aerosol-forming substrate.

[0170] Example Ex24. An aerosol-generating article according to any preceding example, wherein the aerosolgenerating article comprises a second cover, for example a second paper cover.

[0171] Example Ex25. An aerosol-generating article according to example Ex24, wherein the aerosol-forming substrate is sewn with the at least one thread to the second cover.

[0172] Example Ex26. An aerosol-generating article according to example Ex24 or Ex25, wherein the cover covers a second surface, or at least 50, 80 or 90 percent of the second surface, of the aerosolforming substrate.

[0173] Example Ex27. An aerosol-generating article according to example Ex26, wherein at least a portion of the second cover is located between a portion of the at least one thread extending along the substrate in the second along direction and the aerosol-forming substrate.

[0174] Example Ex28. An aerosol-generating article according to any of examples Ex24 to Ex27, wherein the cover is located on a substantially opposite side of the aerosol-forming substrate to the second cover.

[0175] Example Ex29. An aerosol-generating article according to any of examples Ex24 to Ex28, wherein the cover and the second cover are part of a wrapper, the wrapper optionally encircling the aerosolforming substrate or circling around at least 180, 270 or 315 degrees of the aerosol-forming substrate.

[0176] Example Ex30. An aerosol-generating article according to any of examples Ex1 to Ex3, wherein the aerosol-forming substrate comprises a first layer of aerosol-forming material and a second layer of aerosol-forming material.

[0177] Example Ex31. An aerosol-generating article according to example Ex30, wherein one or both of the first layer of aerosol-forming material and the second layer of aerosol-forming material is sewn with the at least one thread.

[0178] Example Ex32. An aerosol-generating article according to example Ex31 , wherein at least a first portion of the at least one thread is located between the first layer of aerosol-forming material and the second layer of aerosol-forming material. Example Ex33. An aerosol-generating article according to example Ex32, wherein: the first layer of aerosol-forming material has a first layer length, a first layer width, and a first layer thickness, the first layer length and the first layer width being at least two times the first layer thickness; and the second layer of aerosol-forming material has a second layer length, a second layer width, and a second layer thickness, the second layer length and the second layer width being at least two times the second layer thickness.

[0179] Example Ex34. An aerosol-generating article according to example Ex33, wherein: the first layer of aerosol-forming material has a first surface defined by the first layer length and the first layer width; the second layer of aerosol-forming material has a second surface defined by the second layer length and the second layer width; and at least the first portion of the at least one thread is located between the first surface of the first layer of aerosol-forming material and the second surface of the second layer of aerosol-forming material.

[0180] Example Ex35. An aerosol-generating article according to example Ex34, wherein at least the first portion of the at least one thread is in contact with one or both of the first surface of the first layer of aerosolforming material and the second surface of the second layer of aerosol-forming material.

[0181] Example Ex36. An aerosol-generating article according to example Ex34 or Ex35, wherein at least the first portion of the at least one thread acts as a spacer between the first surface of the first layer of aerosol-forming material and the second surface of the second layer of aerosol-forming material.

[0182] Example Ex37. An aerosol-generating article according to example Ex34 or Ex35 or Ex36, wherein the aerosol-generating article defines an air flow path between the first surface of the first layer of aerosol-forming material and the second surface of the second layer of aerosol-forming material.

[0183] Example Ex38. A method of making an aerosol-generating article according to any preceding example, wherein the method comprises: sewing at least a portion of an aerosol-forming substrate with at least one thread.

[0184] Example Ex39. A method according to example Ex38, wherein the method comprises: sewing the aerosol-forming substrate with at least one thread so as to hold the aerosolforming substrate in a compressed state.

[0185] Example Ex40. A method according to example Ex38, wherein the method comprises any one or more of the following steps: providing a rod, the rod comprising or consisting of aerosol-forming substrate material; compressing the rod to form a compressed rod comprising the aerosol-forming substrate in a first compressed state; and sewing the aerosol-forming substrate with the at least one thread so as to hold the aerosolforming substrate in a second compressed state.

[0186] Example Ex41 . A method according to example Ex38, wherein the method comprises any one or more of the following steps: providing a rod, the rod comprising aerosol-forming substrate material and a wrapper encircling the aerosol-forming substrate material; compressing the rod to form a compressed rod comprising the aerosol-forming substrate in a first compressed state; sewing the aerosol-forming substrate with the at least one thread to the wrapper so as to hold the aerosol-forming substrate in a second compressed state; cutting the wrapper.

[0187] Example Ex42. A method according to example Ex38, wherein the aerosol-forming substrate comprises a first layer of aerosol-forming material and a second layer of aerosol-forming material, and the method comprises sewing the first layer of aerosol-forming material of the aerosol-forming substrate with the at least one thread, for example with at least one first thread.

[0188] Example Ex43. A method according to example Ex42, wherein the method comprises sewing the second layer of aerosol-forming material the aerosol-forming substrate with the at least one thread, for example with at least one second thread.

[0189] Example Ex44. A method according to example Ex42 or Ex43, wherein the method comprises sewing the first layer of aerosol-forming material to the second layer of aerosol-forming material with the at least one thread, for example with at least one combining thread.

[0190] Examples will now be further described with reference to the figures in which:

[0191] Figure 1 is a perspective view of an aerosol-generating article according to a first embodiment of the present disclosure;

[0192] Figure 2 is a perspective view of an aerosol-generating article according to a second embodiment of the present disclosure;

[0193] Figure 3 is a perspective view of an aerosol-generating article according to a third embodiment of the present disclosure;

[0194] Figure 4 is a perspective view of an aerosol-generating article according to a fourth embodiment of the present disclosure;

[0195] Figure 5 is a perspective view of an aerosol-generating article according to a fifth embodiment of the present disclosure;

[0196] Figure 6 shows a perspective view of an aerosol-generating article according to a sixth embodiment of the present disclosure;

[0197] Figure 7 shows a perspective view of an aerosol-generating article according to a seventh embodiment of the present disclosure;

[0198] Figure 8 shows an exploded perspective view of the aerosol-generating article of figure 7;

[0199] Figure 9 shows a further exploded perspective view of the aerosol-generating article of figure 7;

[0200] Figure 10 shows a schematic transverse cross-sectional view of the aerosol-generating article of figure 7;

[0201] Figure 11 shows a schematic longitudinal cross-sectional view of the aerosol-generating article of figure 7;

[0202] Figure 12 shows schematically a method of manufacturing an aerosol-generating article according the present disclosure;

[0203] Figure 13 shows schematically a method of manufacturing an aerosol-generating article according to the present disclosure; Figure 14 shows exploded views of two further aerosol-generating articles according to the present disclosure.

[0204] Figure 15 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 according to the present disclosure;

[0205] Figure 16 shows a schematic end view of the aerosol-generating device of figure 15;

[0206] Figure 17 is a schematic view showing an aerosol-generating article (for example, any aerosolgenerating article according to the present disclosure) in engagement with the aerosol-generating device of figure 15.

[0207] Figure 18 is a schematic view of an alternative embodiment to that of figures 15 to 17, showing an aerosol-generating article in engagement with an aerosol-generating device.

[0208] Figure 1 illustrates a perspective view of an aerosol-generating article 100 according to a first embodiment of the present disclosure. The aerosol-generating article 100 has upper and lower surfaces 110, 120 which are flat or planar.

[0209] The aerosol-generating article 100 comprises an aerosol-forming substrate (not shown). In one embodiment, the aerosol-generating article 100 may consist substantially of aerosol-forming substrate and a thread 125. In another embodiment, the aerosol-forming substrate and the thread 125 may be two of three or more 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 an exterior of the aerosol-generating article 100; for example, one or both of the upper and lower surfaces 110, 120 may comprise or consist of aerosol-forming substrate.

[0210] A suitable aerosol-forming substrate may be homogenised tobacco.

[0211] 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.

[0212] The thread 125 is a cotton thread that has been impregnated with a menthol flavourant. The substrate is sewn with the thread 125 to limit expansion of the substrate from the shape and size shown in Figure 1 . In particular, the substrate is sewn along a length of the substrate and through a thickness of the substrate to form the linear stitching pattern shown in Figure 1. The thread 125 extends into the substrate at a first location 131 , then through the substrate in a first through direction parallel with the substrate thickness direction, then along a lower surface of the substrate in a first along direction parallel with the substrate length direction, then back into through the substrate at a second location, then through the substrate in a second through direction, substantially opposing the first through direction, then out of the substrate at a third location 133, then along the substrate in a second along direction, substantially parallel to the first along direction. This pattern repeats along a length of the substrate, as shown in Figure 1.

[0213] Figure 2 illustrates a perspective view of an aerosol-generating article 200 according to a second embodiment of the present disclosure. 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 230 is defined through the aerosol-generating article 200 between the upper and lower surfaces 210, 220. The air flow path 230 extends between opposed first and second ends 201 , 202 of the aerosol-generating article 200. 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.

[0214] As with the embodiment of figure 1 , the article 200 of figure 2 comprises a thread 225. However, this thread 225 forms a zig-zag stitching pattern, unlike the linear stitching pattern of Figure 1 . Thus, the thread 225 extends through the article 200 in a z direction, similarly to the embodiment of Figure 1 , but the first and second along directions are not parallel with the article length or x direction. Instead, whilst making a first part, or “zig” of the zig-zag stitching pattern, the thread 225 extends along the upper surface 210 or lower surface 220 in a direction in the x-y plane at an angle of around 40 degrees from the x direction and around 50 degrees from the y direction. Then, whilst making a second part, or “zag” of the zig-zag stitching pattern, the thread 225 extends along the upper surface 210 or lower surface 220 in a direction in the x-y plane at an angle of around 50 degrees from the x direction and around 60 degrees from the y direction.

[0215] Figure 3 illustrates a perspective view of an aerosol-generating article 300 according to a third embodiment of the present disclosure.

[0216] The article 300 comprises an aerosol-forming substrate in the form of a sheet 305 of homogenised tobacco which has been formed from a cast leaf process, then gathered or folded on itself to form a substantially cuboid shaped aerosol-forming substrate, then sewn with a first thread 325, a second thread 326, and a third thread 327. In other embodiments, there could be multiple sheets forming the substrate.

[0217] The sheet 305 defines an upper surface 310 and a lower surface 320 of the aerosol-forming substrate. The first thread 325 extends into the upper surface 310 of the substrate at a first location 331 , then through the substrate in a first through direction parallel with the substrate thickness or z direction, then out of the lower surface 320 of the substrate, then along the lower surface 320 of the substrate in a first along direction parallel with the substrate length or x direction, then back into the lower surface 310 at a second location, then through the substrate in a second through direction, substantially opposing the first through direction, then out of the upper surface 310 of the substrate at a third location 333, then along the substrate in a second along direction, substantially parallel to the first along direction. This pattern repeats along a length of the substrate, as shown in Figure 3. The substrate is similarly sewn with the second thread 326 and the third thread 327, and the first, second and third threads 325, 326, 327 are spaced from each other in a substrate width or y direction.

[0218] In this embodiment, the threads 325, 326, 327 are commercially available cotton threads reinforced with stainless steel. The stainless steel acts as a susceptor material. Thus, in an at least partly inductively heated aerosol-generating system, the threads 325, 326, 327 are heated in the presence of an alternating electromagnetic field and help to heat the aerosol-forming substrate to form an aerosol.

[0219] The sheet 305 has a thickness of around 300 microns. The aerosol-generating article 300 has a length, extending in an x dimension, of 80 millimetres, a width, extending in a y dimension, of 15 millimetres, and a height (or thickness), extending in a z dimension, of 3.6 millimetres.

[0220] As the skilled person would understand after reading this disclosure, the Figures are schematic. The sheet 305 may be folded many more times than shown in Figure 3 to form the substrate.

[0221] Figure 4 shows an aerosol-generating article 600 according to a fourth embodiment of the present disclosure. The aerosol-generating article 600 comprises an aerosol-forming substrate in the form of a plurality of crimped sheets 605 of homogenised tobacco which have been formed from a cast leaf process.

[0222] To form the article, the sheets 605 are cast and dried and cut, then gathered to form a substantially right circular cylindrical rod of aerosol-forming substrate. The rod is then wrapped by a paper wrapper 640 to form a wrapped rod. The wrapped rod is then compressed between a pair of rollers to form a compressed rod having a substantially cuboid or oval transverse cross-section. The compressed rod is then then sewn with a first thread 625 and a second thread 626. This holds the substrate in a compressed state and prevents or restricts expansion of the substrate back towards its original shape prior to being compressed by the pair of rollers.

[0223] The wrapper 640 defines a substantially planar upper surface 610 and a substantially planar lower surface 620 of the article 600. The first thread 625 extends in a first through direction parallel with the substrate thickness or z direction into the wrapper 640 at a first location 631 on the upper surface 610, then through the wrapper 640, the substrate, and back through the wrapper 640 on the lower surface 620. The first thread 625 then extends along the lower surface 620 of the wrapper in a first along direction parallel with the substrate length or x direction. The first thread 625 then extends in a second through direction, substantially opposing the first through direction, into the wrapper 640 at a second location on the lower surface 620, then through the wrapper 640, the substrate, and back through the wrapper 640 at a third location 633 in the upper surface 610. The first thread 625 then extends along the upper surface 610 in a second along direction, substantially parallel to the first along direction. This pattern repeats along a length of the substrate, as shown. Thus, the substrate is sewn to the wrapper 640 by the first thread 625.

[0224] The substrate is similarly sewn to the wrapper 640 by the second thread 626, but the second thread 626 is spaced from the first thread 625 in a substrate width or y direction. As the skilled person would understand after reading this disclosure, in other embodiments, the threads 625, 626 could extend along the substrate in a y direction and be spaced apart from one another in the x-direction instead.

[0225] In this embodiment, the first thread 625 is a cotton thread impregnated with a liquid menthol flavourant and the second thread 626 is a cotton thread reinforced with stainless steel. The stainless steel acts as a susceptor material. Thus, in an at least partly inductively heated aerosol-generating system, the thread 626 is heated in the presence of an alternating electromagnetic field and helps to heat the aerosolforming substrate to form an aerosol.

[0226] The sheets 605 each have a thickness of around 300 microns. The aerosol-generating article 600 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.

[0227] An air flow path 630 is defined through the aerosol-generating article 600 between the upper and lower surfaces 610, 620. The air flow path 630 extends between opposed first and second ends 601 , 602 of the aerosol-generating article 600. The first end 601 may define a distal end of the aerosol-generating article 600, and the second end 602 may define a proximal or mouth end of the aerosol-generating article 600. Alternatively, the article 600 may be configured for insertion into another article with another mouth end. The air flow path 630 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 600.

[0228] The paper wrapper 640 in this embodiment forms a cover for the aerosol-forming substrate that encircles the aerosol-forming substrate in the y-z plane. In other embodiments, the paper wrapper 640, and optionally some of the substrate, may be cut on one or both sides so as to remove one or both of the faces in the x-z plane. If cut on only one side, the paper wrapper may still be a unitary component but may not quite encircle the substrate - the wrapper may then have a taco-like shape around the substrate. If cut on both sides, the wrapper may have been then effectively cut to form two separate components - a first cover forming an upper layer of the article and a second cover forming a lower layer of the article.

[0229] Figure 5 shows an aerosol-generating article 700 according to a fifth embodiment of the present disclosure.

[0230] To form the article 700, the paper wrapper 640 of the article 600 shown in Figure 6 is cut on both sides to remove the two faces of the wrapper 640 in the x-z plane. Thus, the article 700 comprises a first paper cover 741 forming a first, upper layer of the article 700 and a second paper cover 742 forming a second, lower layer of the article 700. The article 700 is otherwise identical to the article 600 of Figure 6.

[0231] Figure 6 shows an exploded view of an aerosol-generating article 800 according to a sixth embodiment of the present disclosure.

[0232] The article 800 comprises a first layer 810, a second layer 820, a third layer 830 and a fourth layer 840. Each layer is a sheet of aerosol-forming material, specifically homogenised tobacco formed by a cast leaf process in this embodiment. These layers together form an aerosol-forming substrate. Each sheet has a thickness of around 300 microns. As the skilled person would appreciate after reading this disclosure, in other embodiments there may be more or fewer layers.

[0233] The first layer 810 is sewn with a first thread 812, as well as other threads spaced from the first thread 812 in the y-direction, to form linear stitching patterns in the layer along an x-direction. The second layer 820 is sewn with a second thread 822, as well as other threads spaced from the second thread 822 in the y-direction, to form linear stitching patterns in the layer along an x-direction. The third layer 830 is sewn with a third thread 832, as well as other threads spaced from the third thread 832 in the y-direction, to form linear stitching patterns in the layer along an x-direction. The fourth layer 840 is sewn with a fourth thread 842, as well as other threads spaced from the fourth thread 842 in the y-direction, to form linear stitching patterns in the layer along an x-direction. Each layer 810, 820, 830, 840 comprises one or both of dimples and ridges as a result of being sewn with the threads.

[0234] Each thread 812, 822, 832, 842 is a cotton thread impregnated with a menthol flavourant in this embodiment.

[0235] Portions of each thread 812, 822, 832, 842 are located between the layer sewn with that thread and any adjacent layer. For example, portions of the first thread 812 are located between an upper surface of the first layer 810 and a lower surface of the second layer 822. Similarly, portions of the second thread 822 are located between the lower surface of the second layer 822 and the upper surface of the first layer 810, and other portions of the second thread 822 are located between an upper surface of the second layer 820 and a lower surface of the third layer 830. The threads 812, 822, 832, 842 acts as spacers between the layers 810, 820, 830, 840.

[0236] The article 800 also comprises a combining thread 850. The layers 810, 820, 830, 840 are sewn together with the combining thread 850. In Figure 6, a needle is shown still attached to the combining thread 850. However, the needle is not part of the article 800.

[0237] The combining thread 850 extends into an upper surface of the fourth layer 840, then through the fourth layer 840, the third layer 830, the second layer 820, the first layer 810 and then out of a lower surface of the first layer 810. The combining thread 850 then extends along the lower surface of the first layer 810, in this embodiment in an x-direction. The combining thread 850 then extends back into the lower surface of the first layer 810, through the first layer 810, the second layer 820, the third layer 830, the fourth layer 840 and out of the upper surface of the fourth layer 840. The combining thread 850 then extends along the upper surface of the fourth layer 840, in this embodiment in an x-direction. This pattern then repeats. This forms a linear stitching pattern in the x-direction. As the skilled person would appreciate after reading this disclosure, other options are available. For example, in other embodiments, any one or more of the following may be true: there may be more than one combining thread, the stitching pattern may be non-linear, and the stitching pattern may extend in a y-direction.

[0238] The combining thread 850 in this embodiment is a cotton thread reinforced with stainless steel. The stainless steel acts as a susceptor material. Thus, in an at least partly inductively heated aerosol-generating system, the combining thread 850 is heated in the presence of an alternating electromagnetic field and helps to heat the aerosol-forming substrate to form an aerosol.

[0239] The aerosol-generating article 800 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 1 .6 millimetres.

[0240] In other embodiments, a cover, for example a paper cover, could be present on one or both of a top and a bottom of the article. In this case, the combining thread could sew the layers of the substrate to the cover or covers, similarly to as if the cover or covers were another layer of aerosol-forming material.

[0241] Figure 7 shows an aerosol-generating article 400 according to a seventh embodiment of the present disclosure. The aerosol-generating article 400 comprises a first planar external layer 424 forming a first planar external surface 421 , a second planar external layer 425 forming a second planar external surface 422, and a frame 450 positioned between the first planar external layer 424 and the second planar external layer 425. The second planar external surface 422 is positioned parallel to the first planar external surface 421.

[0242] Figures 8 and 9 show exploded views of the aerosol-generating article 400 of figure 7. The frame 450 circumscribes and at least partially defines a cavity 430. Figure 8 shows the cavity 430 in an empty state. Figure 9 shows the cavity 430 occupied by, optionally filled with, an aerosol-forming substrate 440 or other aerosol-generating article. The aerosol-forming substrate 440 of this embodiment could be, for example, any of the aerosol-forming substrates, or any of the aerosol-generating articles 100, 200, 300, 500, 600, of Figures 1 to 6. As the skilled person would understand, the articles 100, 200, 300, 500, 600 of figures 1 to 6 can be adjusted to have any reasonable dimensions, so could fill the cavity 430 if desired. Figures 10 and 11 show respective transverse and longitudinal cross-sectional views of the aerosolgenerating article 400 when the cavity 430 contains aerosol-forming substrate 440.

[0243] The first planar external layer 424 and the second planar external layer 425 are made from cigarette paper having a thickness of 35 micrometres and are in physical contact, with and bonded to, the frame 450. The first planar external layer 424 overlies a first end of the cavity 430 and forms a first cavity end wall 431 . The second planar external layer 425 overlies a second end of the cavity 430 and forms a second cavity end wall 432, the second cavity end wall 432 being opposite to the first cavity end wall 431 . That is, the frame 450, the first planar external layer 424 and the second planar external layer 425 collectively define the cavity 430. 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.

[0244] An air inlet 411 and an air outlet 412 are defined by, and extend through, the peripheral wall 451 of the frame 450. More specifically, the air inlet 411 extends through the front wall 413 and the air outlet 412 extends through the back wall 414. The air inlet 411 and the air outlet 412 have an equivalent diameter of 5 millimetres. An airflow passage extends between the air inlet 411 and the air outlet 412 through the cavity 430. As shown in figures 9 to 11 , an aerosol-forming 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 aerosolforming substrate 440 may fill the entire volume of the cavity 430 but in other embodiments may not.

[0245] The aerosol-generating article 400 has a cuboid shape and has a height (or thickness) extending in a z dimension, as measured between the first planar external surface 421 and the second planar external surface 422, of 8 millimetres, a width extending in a y dimension of 40 millimetres and a length extending in an x dimension of 60 millimetres. The frame 450 has a height (or thickness) extending in a z dimension of 7.93 millimetres, a width extending in a y dimension of 40 millimetres and a length extending in an x dimension of 60 millimetres. The cavity 430 has a height (or thickness) extending in a z dimension of 7.93 millimetres, a width extending in a y dimension of 30 millimetres and a length extending in an x dimension of 50 millimetres.

[0246] Figure 12 schematically shows a method of making an aerosol-generating article 1200.

[0247] Initially, sheets 1201 of aerosol-forming material, in this case homogenised tobacco, are formed. In the embodiment, the sheets 1201 are formed using a cast leaf process. The sheets 1201 may or may not be crimped. The sheets 1201 together form an aerosol-forming substrate of the article.

[0248] The sheets 1201 are then gathered. In this embodiment, the sheets are passed into a funnel 1202 to gather the sheets and form a substantially right circular cylindrical rod from the sheets 1201 .

[0249] The rod is then wrapped. In this embodiment the rod is wrapped with a paper wrapper 1203 to form a wrapped rod 1204. This step is optional because the paper wrapper 1203 is optional.

[0250] The wrapped rod 1204 is then compressed. In this embodiment, the wrapped rod 1204 is passed between two rollers 1205 and the rollers 1205 compress the wrapped rod 1204 to form a compressed rod 1206 having a substantially oval transverse cross-section and comprising a compressed aerosol-forming substrate 1207 and the paper wrapper 1203.

[0251] The compressed rod 1206 is then sewn. In this embodiment, the compressed rod 1206 is passed through a sewing station in which the compressed aerosol-forming substrate 1207 is sewn with at least one thread 1208 to form a sewn rod. In particular, in this embodiment, the substrate 1207 is sewn to the paper wrapper 1203. In this embodiment, a linear stitching pattern is formed along a length of the substrate 1207. The at least one thread holds the substrate 1207 in a compressed state. The at least one thread restricts expansion of the substrate 1207.

[0252] The sewn substrate is then cut. This step is optional. In this embodiment, the sewn substrate is cut by a paid of circular blades 1209, one circular blade on each side, though in other embodiments only a single side or no sides may be cut. This results in an aerosol-generating article 1200 having a top paper cover 1210 and a bottom paper cover 1211. This article 1200 may, for example, be placed in the cavity of the article 400 described earlier, with or replacing the substrate 440. The two sides 1212, 1213 may be discarded or recycled.

[0253] Figure 13 schematically shows a method of making an aerosol-generating article 1300.

[0254] Initially, sheets 1301 of aerosol-forming material, in this case homogenised tobacco, are formed. In the embodiment, the sheets 1301 are formed using a cast leaf process. The sheets 1301 may or may not be crimped.

[0255] The sheets 1301 are each individually sewn with at least one thread to form sewn sheets. In Figure 13, only a first sheet 1302 and a second sheet 1303 are shown at this first sewing stage, though more sheets are present. In this embodiment, the first sheet 1302 is sewn with two threads, and the second sheet 1303 is sewn with three threads, as shown. Both sheets are sewn to form a linear stitching pattern. This sewing creates dimples and ridges in the sheets. These dimples and ridges, as well as the portions of the threads that are positioned between adjacent sheets in the final aerosol-generating article, provide spaces for airflow and aerosol generation during use. As the skilled person would understand, any given sheet may be sewn with one or more threads, and any given sheet may be sewn in an given direction. It may not be necessary for all of the sheets to be sewn.

[0256] The sewn sheets are then sewn together with at least one combining thread 1304. The combining thread 1304 may be a cotton thread. The combining thread 1304 may be soaked with an aerosol former or flavourant. The combining thread 1304 may comprise a susceptor material. In this embodiment, only a single combining thread 1304 is used.

[0257] The resulting aerosol-generating article 1300 is shown in a cross-sectional view on the right-hand- side of Figure 13. The article 1300 may be used with an aerosol-generating device to generate an aerosol. For example, the article 1300 may be placed in the cavity of the article 400 described earlier, with or replacing the substrate 440.

[0258] Figure 14 shows exploded views of a first article 1401 and a second article 1402. The articles 1401 , 1402 are identical to the article 400 of Figure 4 except that they replace the substrate 440 with an made by the process of Figure 13, for example an article similar or identical to the article 1300 of Figure 13 or the article 800 of Figure 8. In Figure 14, the replacement for the substrate 440 is enlarged for clarity.

[0259] On the left side, an arrangement is shown where: lengths of the layers or sheets of the substrate, the substrate as a whole, and the article all align with the x-direction; widths of the layers or sheets of the substrate, the substrate as a whole, and the article all align with the y-direction; and thicknesses of the layers or sheets of the substrate, the substrate as a whole, and the article all align with the z-direction.

[0260] On the right side, an arrangement is shown where: lengths of the layers or sheets of the substrate, the substrate as a whole, and the article all align with the x-direction; thicknesses of the layers or sheets of the substrate, the width of the substrate as a whole, and the width of the article all align with the y-direction; and widths of the layers or sheets of the substrate, the thickness of the substrate as a whole, and the thickness of the article all align with the z-direction.

[0261] In both arrangements, air flows from left to right in use, through spaces formed between the layers or sheets of aerosol-forming material, the spaces resulting from the threads sewn into the layers or sheets as described previously.

[0262] Figures 15 and 16 illustrate an aerosol-generating device 6000 configured for use with an aerosolgenerating article 900 comprising aerosol-forming substrate 940. The device 6000 is an elongate aerosolgenerating 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 900. 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 900 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.

[0263] Figure 17 illustrates the device 6000 of figure 15 in engagement with the aerosol-generating article 900. There is little tolerance between outer surfaces of the aerosol-generating article 900 and the internal surfaces of the cavity 6050. Thus, there is a snug fit between the aerosol-generating article 900 and the device 6000. As the RTD of the aerosol-generating article 900 is negligible, the RTD of the system formed by the combination of aerosol-generating article 900 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 900 into the cavity 6050, the device 6000 can be operated. The heater 6030 heats a lower surface of the aerosolgenerating article 900, and as a result the aerosol-forming substrate 940 of the aerosol-generating article 900 is heated. Volatile components of the aerosol-forming substrate 940 are evaporated and condense in longitudinal air-flow channels defined within the aerosol-generating article 900 to form an aerosol. The user inhales the aerosol by drawing on the proximal end 901 of the aerosol-generating article 900. Once the aerosol-forming substrate 940 of the aerosol-generating article 900 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 900 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.

[0264] Although figure 17 shows part of the aerosol-generating article 900 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 18 illustrates an alternative embodiment to that of figure 17, with like features referred to by the same reference numbers but with the addition of a prime symbol ’. For the alternative embodiment of figure 18, the entirety of aerosol-generating article 900’ is enclosed within the interior of aerosol-generating device 6000’.

[0265] The articles 900 and 900’ illustrated in Figures 17 and 18 could be for example, any of the articles 100, 200, 300, 600, 700, 800, 400, 1200, 1300, 1401 , 1402, or the article 400 where the substrate 440 is replaced by any of the articles 100, 200, 300, 600, 700, 800, 400, 1200, 1300. Figures 19 and 20 show respective side (or X-Z) and top-down (or X-Y) cross-sections of a further embodiment of an aerosol-generating article 19110. The article 19110 is very similar to the article 400 of Figure 9 except that the aerosol-forming substrate 440 of Figure 9 has been replaced by an alternative aerosol-forming substrate 19150. So in Figure 19, the frame can be seen around the aerosol-forming substrate 19150, whereas in Figure 20, the first and second planar external layers can be seen above and below the aerosol-forming substrate 19150. In both Figures 19 and 20, the air inlet can be seen at the left- hand-side of the article 19110, and the air outlet can be seen at the right-hand-side of the article 19110. Below, only the differences of the article 191 10 compared with the article 400 of Figure 9 are described.

[0266] The article 19110 comprises an aerosol-forming substrate 19150 which comprises an array of aerosol-generating elements 19152 and a joining element 19160.

[0267] Each aerosol-generating element in the array of aerosol-generating elements 19152 has a first planar surface and a second planar surface. In this embodiment, both the first planar surface 19158 and the second planar surface 19159 are circular in shape, though other shapes could be used.

[0268] The at least one joining element 19160 comprises at least one thread 19162 that attaches, by sewing, an aerosol-generating element to an adjacent aerosol-generating element. In this example, the at least one thread 19162 comprises multiple threads, with each thread linking, or sewing, a row of aerosol-generating elements to each other. The at least one joining element 19160 further comprises a carrier sheet 19164. In this embodiment, the carrier sheet 19164 is a fluid-permeable, woven fabric sheet. The at least one thread 19162 links the array of aerosol-generating elements to the carrier sheet 19164. The array of aerosolgenerating elements 19152 are arranged in a regular, partially overlapping pattern.

[0269] The at least one thread 19162 comprises threads that pass through each of the aerosol-generating elements 19152 to join, or sew, each of the aerosol-generating elements to the carrier sheet 19164. In the example shown in Figure 19, the at least one thread 19162 passes from the first planar surface 19158 of an aerosol-generating element to the second planar surface 19159 of the aerosol-generating element, and then from the second planar surface 19159 through the carrier sheet 19164. In Figure 19, the dotted sections of the at least one thread 19162 show where the at least one thread 19162 passes behind the aerosol-generating element. In Figure 20 the dotted sections of the at least one thread 19162 show where the at least one thread 19162 passes through the aerosol-generating element or the carrier sheet 19164.

[0270] The aerosol-forming substrate 19150 comprises multiple layers. In this embodiment, the aerosolforming substrate 19150 comprises a first layer comprising the first set of aerosol-generating elements, a second layer comprising the second set of aerosol-generating elements, third layer comprising a third set of aerosol-generating elements, a fourth layer comprising a fourth set of aerosol-generating elements. As shown by dashed arrows in Figure 20, a portion of the airflow passage is defined between each set of aerosol-generating elements.

[0271] The at least one joining element 19160 comprises: a first joining element linking, or sewing together, the aerosol-generating elements of the first set of aerosol-generating elements; a second joining element linking, or sewing together, the aerosol-generating elements of the second set of aerosol-generating elements; a third joining element linking, or sewing together, the aerosol-generating elements of the third set of aerosol-generating elements; and a fourth joining element linking, or sewing together, the aerosolgenerating elements of the fourth set of aerosol-generating elements. Figures 21 and 22 respectively show a schematic top view, and a side-on schematic cross-sectional view, of a portion of a further embodiment of an aerosol-forming substrate for an aerosol-generating article. Similarly to the aerosol-forming substrate 19150 of Figures 19 and 20, the aerosol-forming substrate of Figures 21 and 22 may replace the aerosol-forming substrate 440 in the article of Figure 9.

[0272] In the embodiment shown in Figures 21 and 22, the aerosol-forming substrate comprises a first type 21354a of aerosol-generating element and a second type 21354b of aerosol-generating element.

[0273] In this embodiment, the first type 21354a of aerosol-generating element comprises cast leaf tobacco and about 35 percent by weight of an aerosol former on a dry weight basis, wherein the aerosol former comprises glycerine. The second type 21354b of aerosol-generating element comprises cast leaf tobacco and about 35 percent by weight of an aerosol former on a dry weight basis, wherein the aerosol former comprises glycerine, and additionally a flavourant.

[0274] Each of the aerosol-generating elements are substantially planar. Each have a first planar surface and a second opposed planar surface. The first and second planar surfaces are circular and have a diameter of about 5 millimetres wide. The first and second planar surfaces are separated by a thickness of the aerosol-generating element. The thickness of the aerosol-generating element is about 100 microns. So the ratio of the diameter to the thickness is about 50.

[0275] The first type 21354a of aerosol-generating element and second type 21354b of aerosol-generating element are situated next to each other and arranged in an alternating pattern. The first type 21354a of aerosol-generating element and the second type 21354b of aerosol-generating element are partially overlapping. As shown in Figure 22, there is spacing between the aerosol-generating elements, such that in use, air may flow between the first type 21354a of aerosol-generating element, a second type 21354b of aerosol-generating element.

[0276] Each of the aerosol-generating elements is attached or sewn by its own thread 21362 to a carrier sheet 21364. Thus, each of the aerosol-generating elements is attached or sewn to the carrier sheet 21364. In this embodiment, the carrier sheet 21364 is a fluid-permeable, woven fabric sheet.

[0277] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term “about”. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number “A” is understood as “A” ± 10% of “A”. Within this context, a number “A” may be considered to include numerical values that are within general standard error for the measurement of the property that the number “A” modifies. The number “A”, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which “A” deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. The terms “in which” and “wherein” are used synonymously through this specification.

Claims

CLAIMS1 . An aerosol-generating article comprising: an aerosol-forming substrate; and at least one thread, wherein at least a portion of the aerosol-forming substrate is sewn with the at least one thread.

2. An aerosol-generating article according to claim 1 , wherein the aerosol-generating article is defined by an article length, an article width, and an article thickness, the article length being at least 2, 3 or 5 times the article thickness and the article width being at least 2, 3 or 5 times the article thickness.

3. An aerosol-generating article according to any preceding claim, wherein the aerosol-forming substrate is defined by a substrate length, a substrate width, and a substrate thickness, the substrate length being at least 2, 3 or 5 times the substrate thickness and the substrate width being at least 2, 3 or 5 times the substrate thickness.

4. An aerosol-generating article according to claim 3, wherein a ratio of the substrate length of the aerosol-forming substrate to a thread length of the at least one thread is between 1 :2 and 1 :20.

5. An aerosol-generating article according to any preceding claim, wherein the aerosol-forming substrate is sewn with the at least one thread to hold the aerosol-forming substrate in a compressed state.

6. An aerosol-generating article according to claim 3 or claim 4, wherein the aerosol-forming substrate is sewn with the at least one thread to hold the aerosol-forming substrate in a compressed state in a direction of the substrate thickness.

7. An aerosol-generating article according to any preceding claim, wherein at least a portion of the at least one thread extends: through the substrate in a first through direction; then along the substrate in a first along direction; then through the substrate in a second through direction; then along the substrate in a second along direction.

8. An aerosol-generating article according to claim 7, wherein the at least one thread extends into the substrate in the first through direction at a first location and extends out of the substrate in the second through direction at a second location, and wherein a distance between the first location and the second location is no more than 10 millimetres.

9. An aerosol-generating article according to any preceding claim, wherein the aerosol-forming substrate is not sewn to any other component of the aerosol-generating article.

10. An aerosol-generating article according to any of claims 1 to 8, wherein the aerosol-forming substrate is sewn with the at least one thread to at least one other component of the aerosol-generating article.

11. An aerosol-generating article according to any of claims 1 to 8, wherein the aerosol-forming substrate comprises a cover and the aerosol-forming substrate is sewn with the at least one thread to the cover.

12. An aerosol-generating article according to any preceding claim, wherein the aerosol-forming substrate comprises a first cover and a second cover separate to the first cover, wherein the first cover is located on a substantially opposite side of the aerosol-forming substrate to the second cover.

13. An aerosol-generating article according to any preceding claim, wherein: the aerosol-forming substrate comprises a first layer of aerosol-forming material and a second layer of aerosol-forming material; one or both of the first layer of aerosol-forming material and the second layer of aerosol-forming material is sewn with the at least one thread; and at least a first portion of the at least one thread is located between the first layer of aerosol-forming material and the second layer of aerosol-forming material.

14. An aerosol-generating article according to claim 13, wherein at least the first portion of the at least one thread acts as a spacer between the first layer of aerosol-forming material and the second layer of aerosol-forming material.

15. A method of making an aerosol-generating article according to any preceding claim, wherein the method comprises: sewing at least a portion of an aerosol-forming substrate with at least one thread.

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