WO2025114566A1

WO2025114566A1 - Aerosol-generating article comprising a roll of aerosol-forming substrate

Info

Publication number: WO2025114566A1
Application number: PCT/EP2024/084156
Authority: WO
Inventors: Kyle Robert Adair; Kei Kwan Clarence CHUM; Frédéric LAVANCHY; Paola ORSOLINI
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2023-12-01
Filing date: 2024-11-29
Publication date: 2025-06-05
Anticipated expiration: 2026-06-01

Abstract

An aerosol-generating article for producing an aerosol. The aerosol-generating article comprising a roll of aerosol-forming substrate, the aerosol-forming substrate being defined by a length, a width, and a thickness, in which the length is greater in magnitude than the width, and the width is greater in magnitude than the thickness, in which the thickness is greater than or equal to 0.5 millimetres, and in which at least a portion of the aerosol-forming substrate is rolled along its length.

Description

AEROSOL-GENERATING ARTICLE COMPRISING A ROLL OF AEROSOL-FORMING SUBSTRATE

The present disclosure relates to an aerosol-generating article, an aerosol-generating system, and a method of manufacturing an aerosol-generating article.

A typical aerosol-generating system comprises an aerosol-generating device and an aerosol-generating article. The aerosol-generating device may comprise heater, and the aerosolgenerating article may comprise an aerosol-forming substrate. In use, the heater of the aerosolgenerating device heats the aerosol-forming substrate of the aerosol-generating article causing the release of volatile compounds from the aerosol-generating substrate. These compounds then cool to form an aerosol that is inhaled by a user.

A typical aerosol-generating article may appear similar to a conventional cigarette. For example, such an aerosol-generating article may be a substantially cylindrical article comprising an aerosol-forming substrate and other components such as mouthpiece filter element, all wrapped in a cigarette paper. Dimensions of typical aerosol-generating articles are often similar to the dimensions of conventional cigarettes. Typically, such aerosol-generating articles are circular in cross-section and extend between opposed first and second open ends. Such an aerosol-generating article typically contains a portion of aerosol-forming substrate having a cylindrical shape corresponding to the circular cross-section of the article.

Typical aerosol-forming articles are usable in a single usage session. For example, the aerosol-generating article is heated for a predetermined amount of time, or until another usage threshold is met, and then heating may be stopped and the usage session ends. The aerosolgenerating article may be removed from the device and disposed of. To start a new usage session, a user must insert another aerosol-generating article into the aerosol-forming device. This requires a user to carry an aerosol generating device and at least one spare aerosolgenerating article for insertion into the device. Carrying spare aerosol-generating articles and having to remove and insert aerosol-generating articles between each usage session may inconvenience the user.

It is desirable to provide an aerosol-generating article that is suitable for use in multiple usage sessions.

According to an aspect of the present disclosure, there is provided an aerosol-generating article for producing an aerosol. The aerosol-generating article may comprise a roll of aerosolforming substrate. The aerosol-forming substrate may be defined by a length, a width, and a thickness. The length may be greater in magnitude than the width. The width may be greater in magnitude than the thickness. The thickness may be greater than or equal to 0.5 millimetres. At least a portion of the aerosol-forming substrate may be rolled along its length.

As the aerosol-forming substrate may be rolled along its length, the aerosol-forming article may conveniently be suitable for use in more than one usage session. For example, a portion of the aerosol-forming substrate may be unrolled from a rolled portion of the aerosol-forming substrate such that an unrolled portion of aerosol-forming substrate is provided. The unrolled portion may be heatable for aerosol generation, without the rolled portion of the aerosolgenerating substrate being heated. In this way, only a portion of the aerosol-forming substrate may be consumed in a usage session. Therefore, the aerosol-generating article is suitable for use in multiple usage session. As such, a user may conveniently only require one article for use in multiple usage sessions, for example in at least two, three, four or five usage sessions. For example, one article may be suitable for use in at least six, seven, eight, nine or ten usage sessions. Advantageously a user is not required to carry multiple aerosol-generating articles. As such, the aerosol-generating article is more convenient for the user than typical single use disposable aerosol-generating articles.

The width being greater than the thickness means that the aerosol-forming substrate may not have a circular or square cross-section. The cross-section of the aerosol-forming substrate may be oval or rectangular. The aerosol-generating article may have a relatively high surface area to volume ratio compared to an aerosol-generating article having a circular cross-section. The circular cross-section of known aerosol-generating articles can lead to a relatively long time to reach adequate temperature for aerosolisation of the aerosol-generating substrate. This may result in non-uniform heating of the aerosol-forming substrate.

Advantageously, the volume of the aerosol-generating substrate may be heated more quickly and in a more uniform manner compared with an aerosol-generating article having a circular cross-section. For example, if being externally heated, a centre portion of the aerosolforming substrate may reach a desired temperature more quickly than in an article with a circular cross-section. As such, heating across the aerosol-forming substrate may be more uniform and thus formation of aerosol may be more uniform throughout the heated portion of the aerosolforming substrate.

The amount of material in the aerosol-forming substrate may be reduced compared with an aerosol-generating article having a circular cross-section through reduction of outer papers and other non-aerosol forming material present in the aerosol-forming substrate thereby potentially lowering costs and reducing environmental impact.

The aerosol-generating substrate may be flat. The aerosol-generating substrate may be planar. Advantageously, this may allow the aerosol-generating substrate to be efficiently heated by a heating element and improves the yield of aerosol generated from the aerosol-generating substrate. By having a large surface area to volume ratio, and by having a reduced thickness compared to its length and width, a heating element can be located such that all of the aerosolgenerating substrate is within a specified distance from the heating element. This has the advantage of providing an improved user experience and reducing wasted aerosol-generating substrate in use.

The thickness being greater than or equal to 0.5 millimetres may allow the aerosol-forming article to contain a sufficient amount of aerosol-forming substrate without being excessively wide or long. This thickness advantageously contributes to the aerosol-generating article being sufficiently robust for use in an aerosol-generating device, while achieving uniform heating and aerosol-generation. The thickness being greater than or equal to 0.5 millimetres may also lead to improved airflow through the aerosol-forming substrate, for example there may be more volume available for air to flow through, for example by way of air channels or pores. The aerosol-forming substrate may therefore have a lower resistance to draw compared with aerosol-generating articles having a lower thickness, which may allow improved aerosolisation. The thickness being greater than or equal to 0.5 millimetres may also allow more complex structures within the aerosol-forming substrate, for example it may allow the aerosol-forming substrate to comprise one or more layers in the thickness direction.

The aerosol-generating article may be configured for use with an aerosol-generating device that is configured to heat a portion of the aerosol-forming substrate. For example, the aerosolforming article may be configured to be inserted into or engaged with the aerosol-generating device.

The aerosol-generating article may be configured such that only a portion of the aerosolgenerating article is heated at a time. For example, the aerosol-generating article may be partially unrolled so that, in use, an unrolled portion of the aerosol-generating article may be heated. Therefore the aerosol-generating article may be configured to be used in multiple usage sessions. Compared with a common cylindrical stick aerosol-generating article, which is single use only, this means that the user does not need to change consumable as often. The aerosol-generating article configured for multiple uses is more convenient for the user because they do not need to change the aerosol-generating article as often.

The roll of aerosol-forming material may be substantially cylindrical, for example the roll of aerosol-forming material may be rolled in an Archimedean spiral. Alternatively, or in addition, the roll of aerosol-forming material may have a height that is equal to the width of aerosol-forming substrate.

The thickness of the aerosol-forming substrate may be greater than or equal to 0.6 millimetres, greater than or equal to 0.7 millimetres, greater than or equal to 0.8 millimetres, or greater than or equal to 0.9 millimetres, for example greater than or equal to 1 millimetre, or greater than or equal to 2 millimetres. Preferably, the thickness of the aerosol-forming substrate may be equal to or greater than 1 .5 millimetres. The thickness of the aerosol-forming substrate may be between 0.5 millimetres and 15 millimetres, for example between 1.5 and 15 millimetres. The thickness of the aerosol-forming substrate may be between 1 millimetre and 8 millimetres, for example between 2 millimetres and 6 millimetres, for example about 1.5 millimetres, or about 2 millimetres, or about 2.5 millimetres, or about 3 millimetres, or about 4 millimetres.

Advantageously, this range of thicknesses may provide a good compromise between the aerosol-forming substrate being sufficiently thick to contain a reasonable quantity of aerosolforming substrate and to confer the advantages described for aerosol-forming substrate having a thickness greater than 0.5 millimetres, but sufficiently thin to allow aerosol-forming substrate furthest from a heater to be heated to a sufficiently high temperature to generate an aerosol without a significant risk of burning the substrate closest to the heater.

The length of the aerosol-forming substrate, in an unrolled condition, may be between 10 millimetres and 10000 millimetres, for example between 20 and 800 millimetres, for example between 30 and 600 millimetres, for example between 150 and 500 millimetres. Advantageously, this length may be suitable to allow use of the aerosol-generating article in multiple usage sessions.

A length of a portion of the aerosol-forming substrate configured for use in a single usage session, in an unrolled condition, may be between 10 millimetres and 100 millimetres, for example between 20 millimetres and 80 millimetres, for example between 30 millimetres and 60 millimetres, for example about 30 millimetres, or about 35 millimetres, or about 40 millimetres, or about 50 millimetres. Advantageously, the length of the portion of the aerosol-forming substrate configured for use in a single usage session, in an unrolled condition, compared to the length of the aerosol-forming substrate, in an unrolled condition, means that the aerosol-forming substrate may be configured for use in at least three usage sessions, for example at least five usage sessions, for example at least seven usage sessions, for example at least ten usage sessions.

The aerosol-generating article may be configured such that, in use, a first portion is heatable by a heating element in a first usage session. For example, in the first usage session a first portion of the aerosol-generating article is in contact with, or adjacent to a heating element, such that the aerosol-forming substrate is heatable by the heating element. After the first portion has been heated and the first usage session is finished, for example, after a predetermined amount of time or a predetermined condition has been met, for example a predetermined number of puffs have been taken, the aerosol-generating article may be further unrolled, such that the first portion of the aerosol-generating article is no longer in range of the heating element to be heatable by the heating element. A second portion of the heating element is now in contact with, or adjacent to a heating element, such that the aerosol-forming substrate is heatable by the heating element, for example in a second usage session. In this way subsequent portions of the aerosol-generating article are configured to be heatable to form an aerosol.

The width of the aerosol-forming substrate may be between 5 millimetres and 60 millimetres, for example between 10 millimetres and 50 millimetres, for example between 15 millimetres and 40 millimetres, for example about 15 millimetres, or about 20 millimetres, or about 25 millimetres, or about 30 millimetres. These widths, in combination with the length and thickness dimensions may provide an aerosol-generating article that may comfortably fit within an aerosolgenerating system which is a comfortable size for a user to hold between their fingers, whilst still providing a sufficient quantity of substrate to generate enough aerosol to satisfy a user during a usage session.

The aerosol-forming substrate may have a Young’s modulus of between 10 MPa and 1000 MPa, for example between 30 MPa and 500 MPa. The Young’s modulus of the aerosol-generating substrate may allow the aerosol-generating substrate to be rolled along its length. The Young’s modulus of the aerosol-generating substrate may allow the aerosol-generating to be rolled along its length without breaking or becoming damaged.

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

The aerosol-forming material may comprise one or more organic materials such as tobacco.

The aerosol-forming substrate may comprise a tobacco based material, for example at least one of cast leaf or cut filler. The aerosol-forming material may comprise one or more of herb leaf, tobacco leaf, fragments of tobacco ribs, reconstituted tobacco, homogenised tobacco, extruded tobacco and expanded tobacco.

The aerosol-forming substrate may comprise a non-tobacco aerosol forming material comprising an aerosol former, such as glycerine or propylene glycol, preferably including a flavour component and or an active component such as nicotine or a cannabinol. The aerosol-forming substrate may comprise a humectant, for example at least one of propylene glycol, glycerol or water.

The aerosol-forming material may comprise one or more aerosol-formers. Suitable aerosolformers 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 aerosolformer to be or comprise glycerine.

The aerosol-forming substrate may comprise at least one of paper or paperboard.

The aerosol-forming material may comprise cellulose fibres. The aerosol-forming material may comprise cotton.

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

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

The aerosol-forming material may comprise one or more flavourants. The aerosol-forming substrate may comprise a flavourant, for example at least one of menthol, L-Carvone (spearmint), ethyl methylphenylglycidate (strawberry), or peppermint oil.

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.

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

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

The aerosol-forming material may comprise organic botanical extracts. For example, the aerosol-forming material may comprise about 1 to 15 %, preferably of about 2 to 7 %, of any of the previously referred botanicals, as well as menthol (dl-Menthol, C10H20O, 2-lsopropyl-5- methylcyclohexanol) such as obtained from Chaerophyllum macrospermum, Mesosphaerum sidifolium, or other related botanic varieties, as well as P-menthan-3-ol, as any secondary alcohol as diastereoisomers of 5-methyl-2-(propan-2-yl)cyclohexan-1 -ol.

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

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

The aerosol-forming material may comprise particles of a functional material, for example particles of carbon, graphite, activated carbon, or expanded graphite. Such materials may, for example, increase the thermal conductivity of the aerosol-forming material and improve efficiency of aerosol generation.

The aerosol-forming substrate may further comprise a thermally conductive layer, for example an aluminium layer. A thermally conductive layer may facilitate thermal transfer between a heat source and the aerosol-forming material of the aerosol-forming substrate.

The aerosol-forming substrate may further comprise a paper layer, for example a tipping paper layer, covering at least a portion of at least one surface of the aerosol-forming substrate, for example at least a portion of an upper surface, or at least a portion of a lower surface.

The aerosol-forming substrate may comprise conductive materials. For example, the aerosol-forming material may comprise conductive particles. Conductive particles may be, for example, conductive carbon or graphite particles, or conductive metallic particles, for example particles of aluminium, or stainless steel, or nickel.

The aerosol-forming substrate may comprise one or more susceptor materials. The one or more susceptor materials may be incorporated within an aerosol-forming material of the aerosolforming substrate, for example as particles of susceptor material distributed within the aerosol- forming material. The presence of susceptor materials may allow the aerosol-forming substrate to be heated by engagement with a fluctuating electromagnetic field formed by an inductor.

Optionally, one or more susceptor materials may be incorporated within the aerosol-forming substrate as one or more strips, threads, or wires of susceptor material, for example one or more strips, threads, or wires of susceptor material located within an airflow path of the aerosol-forming substrate.

Optionally, one or more susceptor materials may be incorporated within the aerosol-forming substrate as one or more sheets or layers of susceptor material, for example one or more sheets or layers of susceptor material covering an external portion of the aerosol-forming substrate or forming a structural component of the aerosol-forming substrate.

The one of more sheets of susceptor material may be in the form of a mesh of susceptor material.

The susceptor material, in whatever form, may comprise one or more materials selected from the list consisting of: aluminium, iron and iron alloys, nickel and nickel alloys, cobalt alloys, stainless steel alloys, copper alloys, carbon, expanded carbon, and graphite.

The aerosol-forming substrate may comprise a at least one of a ferrous metal, or a ferrous metal alloy. The aerosol-forming substrate may comprise a metal foil.

The aerosol-forming substrate may comprise two or more layers, for example two or more layers laminated together. For example, the aerosol-forming substrate may comprise at least a first planar layer forming an upper surface of the aerosol-forming substrate and a second planar layer forming a lower surface of the aerosol-forming substrate.

The two or more layers may be joined together by an adhesive, for example glue. The two or more layers may be joined together with at least one of: PVA, gum arabic, PU, epoxy, cyanoacrylate, polychloroprene, water-based glue, starch-based glue, cellulose-based glue, or natural rubber-based glue.

The aerosol-forming substrate may comprise a first planar layer, a second planar layer, and an intermediate layer or separation layer arranged between the first planar layer and the second planar layer, at least one of the first planar layer, the second planar layer and the intermediate or separation layer comprising or consisting of an aerosol-forming material.

At least one of the first planar layer, the second planar layer and the intermediate layer or separation layer may comprise or consist of an aerosol-forming material.

Preferably, the aerosol-forming substrate comprises a corrugated portion, for example one or more corrugated elements, such as a corrugated layer. For example, the corrugated layer is a corrugated sheet of material. The one or more corrugated elements preferably define a plurality of air flow channels extending through the aerosol-forming substrate. Corrugations may be formed in a number of different corrugation profiles. For example, the corrugations may be further defined by a corrugation profile, in which the corrugation profile is sinusoidal, or triangular, or rectangular, or trapezoidal, or toroidal, or parabolic.

The intermediate layer or the separation layer may be a corrugated layer. For example, the aerosol-forming substrate may comprise a first planar layer, a second planar layer, and a corrugated layer arranged between the first planar layer and the second planar layer, at least one of the first planar layer, the second planar layer and the corrugated layer may comprise or consist of an aerosol-forming material.

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

An air flow path may be defined through the substrate. The air flow path may be defined by at least one corrugated element. For example, ridges and troughs of the at least one corrugated element may be aligned substantially parallel to the air flow direction thereby forming an air flow path in that direction.

The aerosol-forming substrate comprises an aerosol-forming material. Preferably the aerosol-forming material forms at least part of a corrugated structure or corrugated element. The aerosol-forming material may be in the form of a sheet used as one or more of the components of a corrugated structure or corrugated element. This may allow great flexibility in selection of different combinations of aerosol-forming materials. This may also allow selection of suitable nonaerosol-forming materials to be used for other purposes, for example to improve the structure of the substrate. In some examples, the entire aerosol-forming substrate is formed from aerosolforming materials.

The first planar layer may be an upper layer. The second planar layer may be a lower layer. The intermediate layer may be situated between the upper layer and the lower layer.

Preferably, the upper layer comprises, or is formed from, a planar sheet of material, the lower layer comprises or is formed from a planar sheet of material, and the intermediate layer comprises or is formed from a corrugated sheet of material. In this case, at least some of the air flow channels formed by the corrugations are at least partially bounded by aerosol-forming material. This allows for an aerosol generated from the aerosol-forming material to be easily entrained in the air flow path.

The corrugated layer comprises corrugations that may be arranged perpendicular to the length direction of the aerosol forming substrate, in an unrolled condition, and parallel to the width direction of the aerosol-forming substrate. For example, the corrugations may be arranged perpendicular to the rolling direction of the aerosol-forming substrate. The corrugations being perpendicular to the rolling direction advantageously provide weak resistance to rolling, therefore, allowing the aerosol-forming substrate to be easily rolled and the roll to have a desired radius of curvature.

The intermediate layer or the separation layer may be a crimped layer. The crimped layer may comprise or consist of a crimped tobacco layer.

The intermediate layer or the separation layer may have a honeycomb structure. The honeycomb structure may comprise numerous holes through the layer. The arrangement of the holes may be omnidirectional. The honeycomb layer does not need to be arranged in any particular direction in relation to the rolling direction of the aerosol-forming substrate.

The intermediate layer or the separation layer may comprise or consist of a porous material. The porous material may inherently contain voids. The porous material may be impregnated with an aerosol-forming material. For example, the voids may contain an aerosol-forming material.

The intermediate layer or the separation layer comprise or consist of a fibrous material. The fibrous material may be impregnated with an aerosol-forming material.

The length of the aerosol-forming substrate, in its unrolled condition, may be defined by an x dimension extending in an x direction. The width of the aerosol-forming substrate, in its unrolled condition, may be defined by a y dimension extending in a y direction. The height or thickness of the aerosol-forming substrate, in its unrolled condition, may be defined by a z dimension extending in a z direction.

The aerosol-forming substrate, in its unrolled condition, may comprise a substantially planar upper surface defined by a length extending in an x direction and a width extending in a y direction, and a substantially planar lower surface defined by a length extending in an x direction and a width extending in a y direction. The substantially planar upper surface and the substantially planar lower surface may be vertically spaced from each other by a height defined in a z direction. The height defined in the z direction may be the thickness of the aerosol-forming substrate.

An air flow path may be defined through the aerosol-forming substrate. A low resistance air flow path may be defined through the aerosol-forming substrate, for example the aerosol-forming substrate may have a resistance to draw (RTD), along the air flow path, of less than 80 millimetre H2O, or less than 40 millimetre H2O, or less than 30 millimetre H2O. An aerosol-forming substrate 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-forming substrate and guided to a user.

An air flow path may extend through the substrate in its y dimension from one side edge to the other side edge, for example the air flow path may extend substantially in the y direction. An air flow path may extend through the substrate in its x dimension from one end to the other end, for example the air flow path may extend substantially in the x direction.

An air flow path through the aerosol-forming substrate may be defined in terms of porosity, for example a percentage of the substrate that is free of aerosol-forming material. The porosity in this case is open porosity, allowing an air flow path through the substrate. Thus, an aerosolforming substrate may have an air flow path defined through the aerosol-forming substrate in an x/y plane from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate, and the aerosol-forming substrate may have a porosity of greater than 60 percent, for example greater than 80 percent, in the direction of the air flow path. The porosity may be greater than 60 percent, for example greater than 80 percent, in at least one direction in an x/y plane of the aerosol-forming substrate. The aerosol-forming substrate may have a porosity in a direction perpendicular to the z direction, the porosity of greater than 60 percent, for example greater than 80 percent. For example, an air flow path may be defined through the aerosol-forming substrate along the x direction from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate, such that the aerosol-forming substrate has a porosity of greater than 60 percent, for example greater than 80 percent, in the x direction. The aerosol-forming substrate may have an air flow path defined through the aerosol-forming substrate along the y direction from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate, such that the aerosol-forming substrate has a porosity of greater than 60 percent, for example greater than 80 percent, in the y direction. The porosity of the air flow path may be defined by a ratio of the cross-sectional area of material within the air flow path and an internal cross-sectional area of the air flow path.

Preferably, the porosity is between 81 percent and 99 percent, for example a porosity of between 85 percent and 95 percent, for example between 88 percent and 92 percent, for example about 90 percent, in the direction of the air flow path.

A radius of curvature of the aerosol-forming substrate at an innermost portion of the roll may be less than 4 times the thickness of the aerosol-forming substrate, for example less than 3.5 times the thickness, or less than 3 times the thickness, or less than 2.5 times the thickness, or less than 2 times the thickness.

A radius of curvature of the aerosol-forming substrate at an innermost portion of the roll may be between 2 millimetres and 30 millimetres, for example between 2.5 millimetres and 20 millimetres, for example between 3 millimetres and 15 millimetres, for example between 4 and 8 millimetres.

Advantageously, the selected radius of curvature means the rolled aerosol-forming substrate may be rolled in a compact manner and therefore may be practical for a user to carry and the aerosol-generating article is suitable for insertion into a handheld aerosol-generating device.

As used herein, the “radius of curvature” of the aerosol-forming substrate is the radius of a circle that touches a curve of the aerosol-forming substrate at a given point of the curve. The radius of curvature of the aerosol-forming substrate may be measured at a surface of the aerosolforming substrate that is facing the centre of the circle.

The aerosol-forming substrate may be rolled onto a spool. The aerosol-forming substrate may be rolled onto a spindle. The aerosol-forming substrate may be rolled onto a shaft of a spool. The spindle may be configured to act as an axle for the roll of aerosol-forming substrate to unravel from, as required. A maximum thickness or diameter of the spindle or shaft may be between 2 millimetres and 10 millimetres, for example between 3 millimetres and 9 millimetres, for example between 4 millimetres and 8 millimetres. These thicknesses allow the aerosol-forming substrate to be rolled with a small radius of curvature.

The roll of aerosol-forming substrate may be located within a casing, for example a substantially cylindrical casing. Advantageously, the casing may protect the aerosol-forming substrate.

The casing may comprise a casing cap for retaining the rolled aerosol-forming substrate within the casing.

The aerosol-forming substrate may be rolled onto the spindle or shaft of a spool, the spindle or shaft of the spool may be located in a substantially radially central portion of the casing, for example the cylindrical casing. The spindle or shaft of the spool may allow the aerosol-forming substrate to be unrolled during use of the aerosol-forming substrate.

The aerosol-generating article may comprise a plurality of perforations, for example sprocket holes, for tensioning the aerosol-forming substrate. For example, the perforations or sprocket holes may facilitate the winding, unwinding, or winding and unwinding, of the roll of aerosol-forming substrate. For example, the perforations or sprocket holes may be arranged for engagement with a mechanical means such as a sprocket. The mechanical means, for example a sprocket, may be provided in an aerosol-generating device.

The plurality of perforations or sprocket holes may be arranged in a line extending in the x direction of the aerosol-forming substrate, for example in two lines that may extend in the x- direction, the two lines being spaced apart in the y direction.

According to a second aspect of the present disclosure, there may be provided an aerosolgenerating article for producing an aerosol. The aerosol-generating article may comprise an aerosol-forming substrate. The aerosol-forming substrate may be defined by a length, a width, and a thickness. The length may be greater in magnitude than the width. The width may be greater in magnitude than the thickness. The thickness may be greater than or equal to 0.5 millimetres. Preferably the thickness may be greater than or equal to 1 .5 millimetres.

The aerosol-generating article of the second aspect may comprise any combination of the features described with respect to any other aspect or example of the present disclosure.

The length of the aerosol-forming substrate may be between 10 millimetres and 10000 millimetres, for example between 20 and 800 millimetres, for example between 30 and 600 millimetres, for example between 150 and 500 millimetres. Advantageously, this length may be suitable to allow use of the aerosol-generating article in multiple usage sessions.

Preferably, the length is at two times greater in magnitude than the width. Preferably, the length is at 3, 4, or 5 times greater in magnitude than the width. For example, the length may be at least 10, 15 or 20 times greater than the width.

The aerosol-forming article may conveniently be suitable for use in more than one usage session. For example, a portion of the aerosol-forming may be heatable for aerosol generation, without the remaining amount of the aerosol-generating substrate being heated. In this way, only a portion of the aerosol-forming substrate may be consumed in a usage session. Therefore, the aerosol-generating article is suitable for use in multiple usage session. As such, a user may conveniently only require one article for use in multiple usage sessions, for example in at least two, three, four or five usage sessions. For example, one article may be suitable for use in at least six, seven, eight, nine or ten usage sessions. Advantageously a user may not be required to carry multiple aerosol-generating articles. As such, the aerosol-generating article may be more convenient for the user than typical single use disposable aerosol-generating articles.

According to an aspect of the present disclosure, there may be provided an aerosolgenerating system comprising an aerosol-generating article as described above and an aerosolgenerating device configured to receive the aerosol-generating article.

The aerosol-generating device may be configured to generate an inhalable aerosol from at least a portion of the aerosol-generating article, for example the aerosol-generating device may be configured to heat at least a portion of the aerosol-generating article to form an inhalable aerosol.

The aerosol-generating device may comprise a heater. The aerosol-generating device may comprise a means for applying tension to the aerosol-forming substrate of the aerosol-forming article, such that the aerosol-forming substrate can be unrolled.

The aerosol-generating device may comprise a mechanism configured to unroll the aerosolforming substrate of the aerosol-generating article received in the device.

The aerosol-generating device may comprise an indexing mechanism configured to unroll the aerosol-forming substrate of the aerosol-generating article received in the device. The unrolling of the aerosol-forming substrate may be configured to be effected in intermittent steps. The aerosol-generating device may comprise a display configured to indicate to a user how much of the aerosol generating substrate has been used, alternatively, or in addition it may indicate how much of the aerosol-generating substrate is left to be used. The display may show a use count. The display may indicate the number of usage sessions that the aerosol-generating article has been used in. The display may indicate the number of usage sessions remaining for the aerosol-generating article.

The aerosol-generating device may comprise a heater and an indexing mechanism configured to unroll the aerosol-forming substrate of the aerosol-generating article received in the device. The indexing mechanism may be configured to move the aerosol-forming substrate past the heater in intermittent steps, for example in which the aerosol-forming substrate is within functional heating distance of the heater.

The aerosol-generating system may comprise a heater. The heater may be, or may comprise, a resistance heater. The heater may be, or may comprise, an inductor for heating a susceptor. A corresponding aerosol-generating article may comprise the susceptor.

The heater may be configured to compress a portion of the aerosol-forming substrate. The heater may comprise a first heating element, such as a first heating plate, and a second heating element, such as a second heating plate. The heater may be configured to compress a portion of the aerosol-forming substrate between the first heating plate and a second heating plate. The portion of the aerosol-forming substrate configured to be heated may be under a compression force of between 1 N and 50 N, for example between 5 N and 30 N, for example between 7.5 N and 20 N.

The aerosol-generating device may comprise at least one sprocket for engaging with perforations or sprocket holes defined in the aerosol-forming substrate.

The aerosol-generating device may comprise, or may be configured to receive, an exhaust spindle for receiving aerosol-forming substrate unwound from the aerosol-generating article.

According to an aspect of the present disclosure, there is provided a method for manufacturing an aerosol-generating article. The method may be suitable for manufacturing the aerosol-generating article as described herein.

The method may comprise the steps of providing a continuous sheet of aerosol-forming substrate; cutting the continuous sheet of aerosol-forming substrate to form the aerosol-forming substrate for an aerosol-generating article; rolling the aerosol-forming substrate along its length to form a roll of aerosol-forming substrate, thereby forming an aerosol-generating article.

The method may further comprise the step of forming the continuous sheet of aerosolforming substrate by: providing a first continuous sheet, providing a second continuous sheet, and providing a third continuous sheet, wherein at least one of the first continuous sheet, the second continuous sheet, and the third continuous sheet being a sheet comprising or consisting of aerosol-forming material, texturing the second continuous sheet using a fluting roller to form a continuous corrugated sheet, applying adhesive to at least one of the continuous corrugated sheet or the first continuous sheet, applying a first side of the continuous corrugated sheet to a surface of the first continuous sheet, applying adhesive to at least one of the continuous corrugated sheet and the third continuous sheet, and applying a second side of the continuous corrugated sheet to a surface of the third continuous sheet, thereby forming the continuous sheet of aerosol-forming substrate. At least one of the first second and third continuous sheets may be a sheet of homogenised tobacco.

The resistance to draw (RTD) of the article or aerosol-generating article or a component of the article or aerosol-generating article is expressed with the units of pressure ‘millimetres WG’ or ‘millimetres of water gauge’ or ‘millimetres H2O’.

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-forming substrate. 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 in accordance with ISO 6565-2015 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%.

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

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 material may be adsorbed, coated, impregnated, or otherwise loaded onto a carrier or support. As used herein, the terms “aerosolforming substrate” and ““aerosol-generating substrate” may be used interchangeably.

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

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

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.

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

As used herein with reference to the invention, the terms “proximal”, “distal”, “upstream” and “downstream” are used to describe the relative positions of components, or portions of components, of the cartridge and aerosol-generating system.

As used herein, a "susceptor" means a conductive element that heats up when subjected to a changing magnetic field. This may be the result of eddy currents induced in the susceptor element and/or hysteresis losses.

As used herein, the term ‘usage session’ refers to an operational period of the aerosolgenerating system having a finite duration. A usage session may be a specific type of event that can be performed by the aerosol-generating system. A usage session may be initiated by the action of a user. A usage session may be terminated after a predetermined period of time has elapsed from the initiation of the usage session. A usage session may be terminated after a monitored parameter has reached a threshold during the usage session.

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

Example Ex1 . An aerosol-generating article for producing an aerosol comprising a roll of aerosol-forming substrate, the aerosol-forming substrate being defined by a length, a width, and a thickness, in which the length is greater in magnitude than the width, and the width is greater in magnitude than the thickness, in which the thickness is greater than or equal to 0.5 millimetres, and in which at least a portion of the aerosol-forming substrate is rolled along its length.

Example Ex2. An aerosol-generating article according to example EX1 for use with an aerosol-generating device configured to heat a portion of the aerosol-forming substrate, for example in which the aerosol-forming article is configured to be inserted into or engaged with the aerosol-generating device.

Example Ex3. An aerosol-generating article according to any preceding example in which the roll of aerosol-forming material is substantially cylindrical and/or has a height that is equal to the width of aerosol-forming substrate.

Example Ex4. An aerosol-generating article according to any preceding example in which the thickness of the aerosol-forming substrate is between 0.5 millimetres and 15 millimetres, for example between 1 millimetres and 8 millimetres, for example between 2 millimetres and 6 millimetres, for example about 2 millimetres, or about 2.5 millimetres, or about 3 millimetres, or about 4 millimetres. Example Ex5. An aerosol-generating article according to any preceding example in which the length of the aerosol-forming substrate, in an unrolled condition, is between 10 millimetres and 10000 millimetres, for example between 20 and 800 millimetres, for example between 30 and 600 millimetres, for example between 150 and 500 millimetres.

Example Ex5a. An aerosol-generating article according to any preceding example in which a length of a portion of the aerosol-forming substrate configured for use in a single usage session, in an unrolled condition, is between 10 millimetres and 100 millimetres, for example between 20 millimetres and 80 millimetres, for example between 30 millimetres and 60 millimetres, for example about 30 millimetres, or about 35 millimetres, or about 40 millimetres, or about 50 millimetres.

Example Ex6. An aerosol-generating article according to any preceding example in which the width of the aerosol-forming substrate is between 5 millimetres and 60 millimetres, for example between 10 millimetres and 50 millimetres, for example between 15 millimetres and 40 millimetres, for example about 15 millimetres, or about 20 millimetres, or about 25 millimetres, or about 30 millimetres.

Example 6a. An aerosol-generating article according to any preceding example in which the aerosol-generating substrate has a Youngs modulus of between 10 MPa and 1000 MPa, for example between 30 MPa and 500 MPa.

Example Ex7. An aerosol-generating article according to any preceding example in which the aerosol-forming substrate comprises two or more layers, for example two or more layers laminated together, for example in which the aerosol-forming substrate comprises at least a first planar layer forming an upper surface of the aerosol-forming substrate and a second planar layer forming a lower surface of the aerosol-forming substrate.

Example Ex8. An aerosol-generating article according to example Ex7 in which the aerosol-forming substrate comprises a first planar layer, a second planar layer, and an intermediate layer or separation layer arranged between the first planar layer and the second planar layer, at least one of the first planar layer, the second planar layer and the intermediate or separation layer comprising or consisting of an aerosol-forming material.

Example Ex9. An aerosol-generating article according to example Ex8 in which the intermediate layer or the separation layer is a corrugated layer, for example in which the aerosolforming substrate comprises a first planar layer, a second planar layer, and a corrugated layer arranged between the first planar layer and the second planar layer, at least one of the first planar layer, the second planar layer and the corrugated layer comprising or consisting of an aerosolforming material.

Example Ex10. An aerosol-generating article according to example Ex9 in which corrugations are arranged perpendicular to the length direction of the aerosol forming substrate and parallel to the width direction of the aerosol-forming substrate, for example such that corrugations are arranged perpendicular to the rolling direction of the aerosol-forming substrate.

Example Ex11 . An aerosol-generating article according to any preceding example in which the aerosol-forming substrate, in its unrolled condition, has a length defined by an x dimension extending in an x direction, a width defined by a y dimension extending in a y direction, and a height or thickness defined by a z dimension extending in a z direction.

Example Ex12. An aerosol-generating article according to example Ex11 in which an air flow path is defined through the aerosol-forming substrate, for example in which a low resistance air flow path is defined through the substrate, for example in which the aerosol-forming substrate has a resistance to draw (RTD), along the air flow path, of less than 80 millimetre H₂O, or less than 40 millimetre H₂O, or less than 30 millimetre H₂O.

Example Ex13. An aerosol-generating article according to example Ex1 1 or Ex12 in which an air flow path extends through the substrate in its y dimension from one side edge to the other side edge, for example in which the air flow path extends substantially in the y direction.

Example Ex14. An aerosol-generating article according to example Ex1 1 or Ex12 in which an air flow path extends through the substrate in its x dimension from end to the other end, for example in which the air flow path extends substantially in the x direction.

Example Ex15. An aerosol-generating article according to any preceding example in which a radius of curvature of the aerosol-forming substrate at an innermost portion of the roll is less than 4 times the thickness of the aerosol-forming substrate, for example less than 3.5 times the thickness, or less than 3 times the thickness, or less than 2.5 times the thickness, or less than 2 times the thickness.

Example Ex16. An aerosol-generating article according to any preceding example in which a radius of curvature of the aerosol-forming substrate at an innermost portion of the roll is between 2 millimetres and 30 millimetres, for example between 2.5 millimetres and 20 millimetres, for example between 3 millimetres and 15 millimetres.

Example Ex17. An aerosol-generating article according to any preceding example in which the aerosol-forming substrate is rolled onto a spool.

Example Ex18. An aerosol-generating article according to example Ex17 in which the aerosol-forming substrate is rolled onto a spindle or shaft of a spool, in which a maximum thickness or diameter of the spindle or shaft is between 4 millimetres and 60 millimetres, for example between 5 millimetres and 40 millimetres, for example between 6 millimetres and 30 millimetres.

Example Ex19. An aerosol-generating article according to any preceding example in which the roll of aerosol-forming substrate is located within a casing, for example a substantially cylindrical casing. Example Ex20. An aerosol-generating article according to example Ex19 in which the aerosol-forming substrate is rolled onto the spindle or shaft of a spool, the spindle or shaft of the spool being located in a substantially radially central portion of the casing, for example the cylindrical casing.

Example Ex21. An aerosol- generating article according to any preceding example comprising a plurality of perforations or sprocket holes for tensioning the aerosol-forming substrate, for example for facilitating the winding and/or unwinding of the roll of aerosol-forming substrate, for example in which the perforations or sprocket holes are arranged for engagement with a mechanical means such as a sprocket.

Example Ex22. An aerosol- generating article according to example Ex21 in which the plurality of perforations or sprocket holes are arranged in a line extending in the x direction of the aerosol-forming substrate, for example in two lines extending in the x-direction, the two lines being spaced apart in the y direction.

Example Ex23. An aerosol-generating system comprising an aerosol-generating article according to any preceding example and an aerosol-generating device configured to receive the aerosol-generating article.

Example Ex24. An aerosol-generating system according to example Ex23 in which the aerosol-generating device is configured to generate an inhalable aerosol from at least a portion of the aerosol-generating article, for example in which the aerosol-generating device is configured to heat at least a portion of the aerosol-generating article to form an inhalable aerosol.

Example Ex25. An aerosol-generating system according to example Ex23 or Ex24 in which the aerosol-generating device comprises a heater and means for applying tension to the aerosolforming substrate of the aerosol-forming article, such that the aerosol-forming substrate can be unrolled.

Example Ex26. An aerosol-generating system according to example Ex25 in which the aerosol-generating device comprises a mechanism configured to unroll the aerosol-forming substrate of the aerosol-generating article received in the device.

Example Ex27. An aerosol-generating system according to example Ex25 or Ex26 in which the aerosol-generating device comprises an indexing mechanism configured to unroll the aerosolforming substrate of the aerosol-generating article received in the device, the unrolling of the aerosol-forming substrate configured to be effected in intermittent steps.

Example Ex28. An aerosol-generating system according to any of one of examples Ex25 to Ex27 in which the aerosol-generating device comprises a heater and an indexing mechanism configured to unroll the aerosol-forming substrate of the aerosol-generating article received in the device, the indexing mechanism configured to move the aerosol-forming substrate past the heater in intermittent steps, for example in which the aerosol-forming substrate is within functional heating distance of the heater.

Example Ex29. An aerosol-generating system according to any one of examples Ex23 to Ex28 comprising a heater, in which the heater is, or comprises, a resistance heater or in which the heater is, or comprises, an inductor for heating a susceptor.

Example Ex30. An aerosol-generating system according to any one of examples Ex24 to Ex29, in which the aerosol-generating device comprises at least one sprocket for engaging with perforations or sprocket holes defined in the aerosol-forming substrate.

Example Ex31. An aerosol-generating system according to any one of examples Ex24 to Ex30, in which the aerosol-generating device comprises, or is configured to receive, an exhaust spindle for receiving aerosol-forming substrate unwound from the aerosol-generating article.

Example Ex32: A method of manufacturing the aerosol-generating article according to any preceding example, comprising steps of: providing a continuous sheet of aerosol-forming substrate; cutting the continuous sheet of aerosol-forming substrate to form the aerosol-forming substrate for an aerosol-generating article; rolling the aerosol-forming substrate along its length to form a roll of aerosol-forming substrate.

Example Ex33: The method according to example Ex32, comprising forming the continuous sheet of aerosol-forming substrate by: providing a first continuous sheet, providing a second continuous sheet, and providing a third continuous sheet, wherein at least one of the first continuous sheet, the second continuous sheet, and the third continuous sheet being a sheet comprising or consisting of aerosol-forming material, texturing the second continuous sheet using a fluting roller to form a continuous corrugated sheet, applying adhesive to at least one of the continuous corrugated sheet or the first continuous sheet, applying a first side of the continuous corrugated sheet to a surface of the first continuous sheet, applying adhesive to at least one of the continuous corrugated sheet and the third continuous sheet, and applying a second side of the continuous corrugated sheet to a surface of the third continuous sheet, thereby forming the continuous sheet of aerosol-forming substrate. Example Ex34: The method according to example Ex32 or Ex33, in which at least one of the first second and third continuous sheets is a sheet of homogenised tobacco.

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

Figure 1 a shows a schematic perspective view of an aerosol-generating article according to a first embodiment of the present disclosure;

Figure 1 b shows a schematic perspective view of an aerosol-forming substrate of the first embodiment, in an unrolled condition;

Figure 2a shows a schematic perspective view of a portion of an aerosol-generating article according to a second embodiment; Figure 2b shows a schematic cross-sectional view of a portion of the aerosol-generating article according to the second embodiment;

Figure 3 shows a schematic perspective view of an aerosol-generating article according to a third embodiment;

Figure 4a shows a schematic cross-sectional view of an aerosol-generating system comprising an aerosol-generating article;

Figure 4b shows a schematic, cross-sectional plan view of the aerosol-generating system of Figure 4a; and

Figure 5 shows a schematic illustration of an apparatus used in the manufacture of an aerosol-generating article according to the second embodiment.

Figure 1 a shows a schematic perspective view of an aerosol-generating article 10 according to a first embodiment of the present disclosure. Figure 1 b shows a schematic perspective view of an aerosol-forming substrate 12 of the first embodiment, in an unrolled condition.

As shown in Figure 1 a, the aerosol-generating article 10 comprises an aerosol-generating substrate 12 rolled along a length of the aerosol-forming substrate 12 to form a rolled aerosolgenerating article 10. The aerosol-forming substrate 12 is defined by a length, a width (W), and a thickness (T). The length is greater in magnitude than the width (W) and the width (W) is greater in magnitude than the thickness (T). The thickness (T) of the aerosol-forming substrate is greater than or equal to 0.5 millimetres. In this preferred embodiment, the aerosol-forming substrate has a thickness (T) of between 0.5 millimetres and 15 millimetres, preferably 1.5 millimetres. The width (W) of the aerosol-forming substrate is between 5 millimetres and 60 millimetres, preferably 30 millimetres.

As shown in Figure 1 b, the aerosol-forming substrate 12, in an unrolled condition, has a length (L). The length (L) is between 150 millimetres and 500 millimetres.

The aerosol-generating article 10 is configured to be used with an aerosol-generating device configured to heat a portion of the aerosol-forming substrate. The aerosol-forming article 10 is configured to be inserted into or engaged with the aerosol-generating device. During use, only a portion of the aerosol-forming substrate is heated. The portion of the aerosol-forming substrate to be heated in single usage session, in an unrolled condition, has a portion length (LP) of between 30 millimetres and 60 millimetres, preferably 50 millimetres. This portion of the aerosol-forming substrate may be referred to as the tail of the roll. Figure 1 a shows the portion length (LP) is lesser in magnitude than the width (W). However, it will be appreciated that the portion length (LP) may be equal in magnitude or preferably greater in magnitude than the width (W).

The aerosol-generating article 10 comprises a substantially cylindrical roll 14 of aerosolforming substrate. The radius of curvature of the aerosol-forming substrate 12 at an innermost portion of the roll 14 is less than 4 times the thickness of the aerosol-forming substrate 12. In this example, the radius of curvature is between 3 millimetres and 15 millimetres.

The aerosol-forming substrate 12 has a Youngs modulus of between 30 MPa and 500 MPa.

In use, air will flow through the aerosol-forming substrate 12. An air flow path is defined through the aerosol-forming substrate 12. The air flow path is defined through the portion of aerosol-forming substrate configured to be heated in a usage session. The aerosol-forming substrate may for example have a resistance to draw (RTD) of less than 80 millimetre H₂O, for example less than 40 millimetre H₂O, for example less than 30 millimetre H₂O.

The aerosol-forming substrate 12 comprises aerosol-forming material. A suitable aerosolforming material may be homogenised tobacco.

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

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

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

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

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

5. Aerosol-former; for example, about 5 to 35%, preferably of about 10 to 25%, of an aerosol former. Suitable aerosol-formers known in the art include: glycerine; monohydric alcohols like menthol, polyhydric alcohols, such as triethylene glycol; esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyls of those. “Tobacco type” means one of the different varieties of tobacco, for example based on the distinct curing process that the tobacco undergoes before it is further processed in a tobacco product.

To form the aerosol-forming material, the various components may be mixed together and cast into a sheet having the desired thickness. The sheet may then be dried to be suitable for processing to form the aerosol-forming substrate 12.

For exemplary purposes, a composition of a further aerosol-forming material, which may be suitable as the sheet of aerosol-forming material in the specific embodiment described above, may be as follows. Percentages are given in weight percent with respect to the product in its final state. The aerosol-forming material may comprise:

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

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

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

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

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

Figure 2a shows a schematic perspective view of a portion of an aerosol-generating article according to a second embodiment. The aerosol-generating article 100 comprises an aerosolforming substrate 102. The aerosol-forming substrate 102 comprises a planar upper layer 1 10, a planar lower layer 130, and an intermediate or separation layer 120 arranged between the upper layer 110 and the lower layer 130.

The planar upper layer 110 is formed from a sheet of paper having a thickness of between 0.1 and 0.5 millimetres. The planar lower layer 130 is formed from a sheet of paper having a thickness of between 0.1 and 0.5 millimetres. The intermediate layer 120 comprises a corrugated element formed from a corrugated sheet of aerosol-forming material. A suitable aerosol-forming material may be homogenised tobacco. Thus, in this example, the intermediate layer 120 comprises a corrugated sheet of homogenised tobacco material. The intermediate layer 120 may comprise other suitable aerosol-forming material.

The intermediate layer 120 comprises an aerosol-former 140 such as a viscous liquid or gel. The aerosol-former 140 can be aerosolised by heating of the aerosol-forming substrate. The corrugated sheet of aerosol-forming material may be impregnated with the aerosol-former 140. The aerosol-former 140 may be present in the intermediate layer 120 between the flutes of the corrugated element, the space between the flutes of the corrugated element may be referred to as channels.

The aerosol-generating article 100 comprises perforations, such as sprocket holes 180. The sprocket holes 180 comprise a plurality of apertures that extend through the thickness of the aerosol-forming substrate. The sprocket holes 180 extend from an outer surface of the upper layer 110 to an outer surface of the lower layer 130. The sprocket holes are configured to engage with a sprocket to align the aerosol-forming substrate 102 as it is rolled into the aerosol-forming article and alternatively, or in addition, as it is unrolled from the aerosol-forming article. The plurality of sprocket holes 180 arranged in a line extending along the length (in an unrolled condition) of the aerosol-forming substrate, for example in two lines extending along the length (in an unrolled condition). The two lines of sprocket holes 180 are spaced apart across the width of the aerosol-forming substrate. For example, a first line of sprocket holes is adjacent to a first edge of the outer surface of the upper layer 1 10 and a first edge of the outer surface of the lower layer 130 and a second line of sprocket holes 180 is adjacent to a second edge of the outer surface of the upper layer 1 10 and a second edge of the outer surface of the lower layer 130. Wherein the first edge of the outer surface of the upper layer 1 10 is spaced apart from the second edge of the outer surface of the upper layer 110 across the width of the aerosol-forming substrate and the first edge of the outer surface of the lower layer 130 is spaced apart from the second edge of the outer surface of the lower layer 130 across the width of the aerosol-forming substrate.

Figure 2b shows a schematic cross-sectional view of a portion of the aerosol-generating article according to the second. Figure 2b illustrates the corrugated sheet of aerosol-forming material. The corrugations have an amplitude 122 of between 0.1 millimetres and 0.5 millimetres and a wavelength 124 of between 2 millimetres and 4 millimetres. The sheet of aerosol-forming material forming the intermediate layer 120 has a thickness between 0.1 millimetres and 0.5 millimetres. Points of intersection 170, 160 between the upper layer 1 10 and the intermediate layer 120 and between the lower layer 130 and the intermediate layer 120 comprise an adhesive that joins the respective layers.

Corrugations of the intermediate layer 120 form a first set of transverse channels 172 that are bounded by the upper layer 1 10 and the intermediate layer 120, and a second set of transverse channels 162 bounded by the lower layer 130 and the intermediate layer 120. The first and second set of transverse channels 172, 162 extend through the width of the aerosol-forming substrate 102. The transverse channels 172, 162 define an air flow path through the aerosolforming substrate 102. The air flow path, therefore, passes over both sides of the corrugated sheet of aerosol-forming material. The porosity of the aerosol-forming substrate along the air flow path is in the region of 90 %. This provides a very low resistance to draw of less than 30 millimetre H₂O.

The corrugations of the intermediate layer 120 are transverse to the length of the aerosolforming article. Therefore, the corrugations are perpendicular to the direction of the roll of the aerosol-forming substrate 102 in an aerosol-generating article. As such, the corrugations can provide compressive strength to the aerosol-forming substrate without comprising the ability of the aerosol-forming substrate to be rolled in the length direction.

The corrugated sheet of aerosol-forming material 120 may be a sheet of any suitable aerosol-forming material, as described in the first embodiment.

Figure 3 shows a schematic perspective view of an aerosol-generating article according to a third embodiment. The aerosol-forming substrate 312 of the third embodiment is described below. However, the aerosol-generating article of the third embodiment may comprise any suitable aerosol-forming substrate. For example, the aerosol-generating article may comprise the aerosol-forming substrate 12 described in relation to the first embodiment, or the aerosol-forming substrate 102 described in relation to the second embodiment.

The aerosol-forming substrate 312 is identical to the aerosol-forming substrate 12 of the first embodiment, except where described below.

The aerosol-generating article 300 comprises a spindle 321 . The aerosol-forming substrate 312 is rolled onto the spindle 321. The spindle 321 has a maximum diameter of between 6 millimetres and 30 millimetres. The spindle 321 is configured to rotate. The aerosol-generating substrate 312 can be rolled onto and rolled off of the spindle 321 .

The roll 314 of aerosol-forming substrate is located within a substantially cylindrical casing 316. The spindle 321 is located in a substantially radially central portion of the casing 316.

A casing cap 322 is configured to secure the roll 314 of aerosol-forming substrate within the casing 316. The spindle 321 extends into the casing cap 322. The casing 316 comprising a roll window 382. The roll window 382 allows withdrawal of the aerosol-forming substrate, or a section of the aerosol-forming substrate, from the casing 316.

The aerosol-forming substrate 312 comprises a plurality of sprocket holes 380 for engaging with a corresponding sprocket. The plurality of sprocket holes 380 extend in two lines extending along the length (in an unrolled condition) of the aerosol-forming substrate. The sprocket holes 380 are the same as the sprocket holes 180 described with respect to the second embodiment.

The sprocket holes 380 are suitable for tensioning the aerosol-forming substrate. The sprocket holes 380 facilitate the winding and unwinding of the roll of aerosol-forming substrate. During manufacture of the aerosol-generating article the sprocket holes may be used to engage with a sprocket to facilitate the movement of the aerosol-forming substrate through the manufacturing process. The sprocket holes may also facilitate the winding or rolling of the aerosolforming substrate 312 onto the spindle 323. During use of the aerosol-generating article, the sprocket holes are arranged for engagement with a sprocket in an aerosol-generating device, to unroll or unwind the aerosol-forming substrate 312 from the spindle 323.

Figure 4a shows a schematic cross-sectional view of an aerosol-generating system comprising an aerosol-generating article. The aerosol-generating system 500 comprises the aerosol-generating article 310 of the third embodiment, however any suitable aerosol-generating article may be configured for use in the aerosol-generating system, for example, the aerosolgenerating system may comprise the aerosol-generating article 10 of the first embodiment or the aerosol-generating article 100 of the second embodiment.

The aerosol-generating system 500 comprises an aerosol-generating device 600. The aerosol-generating device 600 comprises an outer casing 680. The outer casing 680 comprises an opening for receiving the aerosol-generating article 300. The outer casing 680 comprises a door 640 configured to cover the opening. The door 640 is openable via a latch 690. The door 640 may open up to an angle 645 ranging from 45° to 120°, preferably 60° to 90°. The door 640 automatically pivots around one end of the device at a spring-loaded hinge 650. Once the door 640 is open, the aerosol-generating article 300 can be loaded into the device 600.

Aerosol-generating device 600 comprises a device sprocket 620 configured to engage with the sprocket holes of the aerosol-generating article 300. The sprocket 620 has teeth 622 configured to engage with the sprocket holes and help to keep the aerosol-forming substrate aligned. The sprocket 620 can rotate to convey the aerosol-forming substrate from the spindle 321 of the aerosol-forming article to the exhaust spindle 630 of the aerosol-generating device 600. The exhaust spindle 630 comprises a slot 631 for receiving aerosol-forming substrate 312. The exhaust spindle 630 is rotatable to unroll the aerosol-forming substrate 312 from the spindle 321 . As the aerosol-forming substrate 312 is unrolled from the spindle 321 it is wrapping around the exhaust spindle 630. The exhaust spindle 630 comprises a spindle lever for a user to rotate the exhaust spindle. Alternatively, the exhaust spindle 630 comprises an electric motor for rotating the exhaust spindle 630.

The device 600 is an elongate aerosol-generating device extending between a proximal end 641 and a distal end 642. The proximal end 641 comprises a mouthpiece 670. The device 600 comprises a battery and a controller (not shown) and a heater 700 located within a housing 680. The controller controls supply of power from the battery to the heater 700. In this embodiment, the heater 700 comprises two heating plates 710, 712. A first heating plate 710 is situated within the housing 680 and configured to be positioned on a first side of the aerosolgenerating substrate, in use. A second heating plate 712 is positioned on the door 640 and configured to be positioned on a second side of the aerosol-generating substrate, in use. The first side of the aerosol-forming substrate opposes the first side. For example, when the aerosolgenerating article comprises an aerosol-forming substrate having an upper layer and a lower layer, the first side may comprise the upper layer and the second side may comprise the lower layer.

An air flow path is defined through the aerosol-generative device 600 and the aerosolforming substrate 312. The aerosol-generating device is configured to allow air to flow into the device through an air inlet. The mouthpiece 670 comprises an air outlet.

The air flow path is shown in more detail in Figure 4b. Figure 4b shows a schematic, cross- sectional plan view of the aerosol-generating system of Figure 4a. As shown in Figure 4b, the aerosol-generating device 600 comprises an air inlet 690. In this embodiment, the air inlet is situated in a side wall of the housing 680. The aerosol-generating device 600 further comprises an air outlet 675. The air outlet 675 is situated in the mouthpiece 670. An air flow path is defined between the air inlet 690 and the air outlet 675. Air can enter the aerosol-generating system 500 via the air inlet 690 and exit the aerosol-generating system 500 via the air outlet 675.

The airflow path is defined through the aerosol-forming substrate 312. In particular, the airflow path is defined through an unrolled portion of the aerosol-generating article. Figure 4b only shows a portion of the aerosol-generating article 300 that is positioned between the first heating plate 710 and the second heating plate 712. Figure 4b shows an example of the air flow path, however, it will be appreciated that any suitable air flow path may be used. For example, the airflow path may be adjusted, for example by re-positioning the air inlet 690.

To use the aerosol-generating system 500, a user opens the door 640 and inserts the aerosol-generating article 300 through the opening of the aerosol-generating device 600. The user aligns the roll tail of the aerosol-forming substrate 312 with the sprocket 620, such that the sprocket teeth 622 engage with the sprocket holes of the aerosol-forming substrate. The roll tail of aerosol-forming substrate is inserted into the slot 631 of the exhaust spindle 630. The user closes the door 640 and the aerosol-generating system 500 is ready for use. When the door 640 is closed, the second heating plate 712 contacts the aerosol-forming substrate 312. A portion of the aerosol-forming substrate 312 is therefore situated between the first heating plate 710 and the second heating plate 712. The portion of aerosol-forming substrate 312 situated adjacent to the heater 700. This portion of the aerosol-forming substrate 312 is situated between the first and second heating plates 710, 712 is configured to be heated during use of the aerosol-generating system 500. The portion of the aerosol-forming substrate configured to be heated by the heater 700 is in contact with the first and second heating plates 710, 712 and may be under a compression force of between 7.5 N and 20 N exerted by the first and second heating plates 710, 712.

The user then activates the aerosol-generating device 600. The user may activate the device via a push button. The push button may be electrically connected to the battery and the controller. The device may comprise a sensor, such a puff sensor configured to detect a puff, such a user inhaling on the mouthpiece of the device. The puff sensor may be electrically connected to the battery and the controller. When the controller receives a signal to indicate that a user has activated the aerosol-generating device, for example via the push button or puff sensor, the controller is configured to activate the heater 700.

The heater 700, via heating plates 710, 712, is configured to heat a portion of the aerosolgenerating article that this situated between the heating plates 710, 712. The heater 700 increases the temperature of the portion of the aerosol-generating article to a temperature of between 200 and 400 degrees Celsius. Volatile components of the aerosol-forming substrate are vapourised. The vapour condenses to form an aerosol for inhalation by the user. In this embodiment, the heater 700 is a resistive heater. However, in other embodiments, the heater 700 may be an inductive heater wherein heating plates are inductors configured to heat a susceptor material that is situated in the aerosol-forming substrate.

In use, the user puffs on the mouthpiece 670 of the aerosol-generating device 600. Air is drawn into the aerosol-generating system 500 via the air inlet 690. The air enters the aerosolforming substrate 312 and cools the vapour generated by the volatile components of the aerosolgenerating substrate. The cooled vapour condenses to form an aerosol. The user inhales the aerosol by drawing on the air outlet 675 of the aerosol-generating system 500. Once the aerosolforming material has been depleted of volatile components, the usage session will stop. The usage session may stop after a predetermined number or puffs, or after a predetermined amount of time.

After a usage session ends, the depleted, used, portion of aerosol-forming substrate 312 between the heating plates 710, 712 is moved out of a heatable range of the heater 700. The exhaust spindle 630 rotates, via a user mechanically rotating the exhaust spindle or via an electric motor, to pull the aerosol-forming substrate 312 towards the exhaust spindle 320. The depleted, used, portion of the aerosol-forming substrate rolls around the exhaust spindle 603 as the exhaust spindle 630 is rotated, such that the used portion of the aerosol-forming substrate is stored on the exhaust spindle 630. The rotation of the exhaust spindle 630 pulls an unused portion of the aerosol-generating substrate out of the rolled portion of the aerosol-generating article and into an area adjacent to the heater 700, between the first heating plate 710 and the second heating plate 712. The aerosol-generating device 600 may comprise a usage indicator that is configured to display the number of usage sessions remaining for an aerosol-generating article. The usage indicator is configured to update when the portion of aerosol-forming substrate has moved from the heater 700 to the exhaust spindle 630.

After a new, unused, portion of the aerosol-forming substrate is positioned between the heating plates 710, 712, the aerosol-generating system is ready for another usage session.

After the aerosol-generating article 300 is depleted, for example after the predetermined number of usage sessions have been completed, then the user can open the door 640 and remove the aerosol-generating article 300 from the aerosol-generating device 600.

Figure 5 illustrates an apparatus 800 that may be used for the manufacture of the aerosolforming substrate 102. Continuous sheets are provided of the three main components of the aerosol-forming substrate, those being a continuous sheet of paper for forming the lower surface 130, a continuous sheet of paper for forming the upper surface 1 10, and a continuous sheet of aerosol-forming material for forming the corrugated intermediate layer 120.

The following steps may occur in the manufacture of the aerosol-forming substrate:

The process starts by creating the single face corrugated structure. A roll of a first continuous sheet 130 is loaded via the single face board bobbin 811 and fed through a series of rollers where it is held taught and made more pliable via heat applied by a preheating roller 812. Simultaneously, the corrugated intermediate layer 120 is made using a series of corrugating rollers 818a and 819a which form the desired profile into the corrugated intermediate layer 120.

A continuous sheet of substrate for the corrugated layer is conveyed under tension to a pair of corrugation rollers or fluting rollers 818a and 819a. The corrugation rollers 818a and 819a texture the continuous sheet of substrate for the corrugated layer to introduce corrugations of the desired wavelength and amplitude.

Adhesive 815, such as glue, is applied to peaks of the corrugations by a first adhesive applicator, the glue applicator roll 814. The corrugated sheet is then brought into contact with the first continuous sheet 130 such that the glue bonds the corrugation peaks in the corrugated intermediate layer 120 to the first continuous sheet 130. At this stage, the material is known as single-face corrugated sheet, and it is held within a transient holding bridge before moving to the next stage of the process.

In next stage of the process, an aerosol-former may be applied to the corrugated intermediate layer 120 via an aerosol-former applicator 833 which may spray or apply the aerosolformer to the corrugated intermediate layer 120.

Next, a further layer, namely a second continuous sheet 110, is applied to corrugated intermediate layer 120, on the side opposite the first continuous sheet 130. The second continuous sheet 110 is glued to the corrugated intermediate layer 120 under pressure and steam applied via steam applicators 829 and pressure plates 830, thereby forming a double-faced planar consumable aerosol-forming substrate.

Sprocket holes can then be added using a punching roller 831 .

Optionally, further aerosol-former can then be injected into the fluted layer channels via an injection point 835, after which the sheet can be cut via knife into the desired planar consumable shape.

In the final stage, the planar consumable can be rolled into an Archimedean Spiral at process step 832 for subsequent use to form the rolled aerosol-forming article.

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 percent 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.

Claims

1 . An aerosol-generating article for producing an aerosol comprising a roll of aerosol-forming substrate, the aerosol-forming substrate being defined by a length, a width, and a thickness, in which the length is greater in magnitude than the width, and the width is greater in magnitude than the thickness, in which the thickness is greater than or equal to 1 .5 millimetres, and in which at least a portion of the aerosol-forming substrate is rolled along its length.

2. An aerosol-generating article according to claim 1 for use with an aerosol-generating device configured to heat a portion of the aerosol-forming substrate, for example in which the aerosol-forming article is configured to be inserted into or engaged with the aerosol-generating device.

3. An aerosol-generating article according to any preceding claim in which the thickness of the aerosol-forming substrate is between 1.5 millimetres and 15 millimetres, the length of the aerosol-forming substrate, in an unrolled condition, is between 30 millimetres and 500 millimetres, and the width of the aerosol-forming substrate is between 5 millimetres and 60 millimetres.

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

5. An aerosol-generating article according to claim 4 in which the aerosol-forming substrate comprises a first planar layer, a second planar layer, and an intermediate layer arranged between the first planar layer and the second planar layer, at least one of the first planar layer, the second planar layer and the intermediate comprising or consisting of an aerosol-forming material.

6. An aerosol-generating article according to claim 5 in which the intermediate layer is a corrugated layer.

7. An aerosol-generating article according to claim 6 in which corrugations are arranged perpendicular to the length direction of the aerosol forming substrate.

8. An aerosol-generating article according to any preceding claim in which the aerosolforming substrate, in its unrolled condition, has a length defined by an x dimension extending in an x direction, a width defined by a y dimension extending in a y direction, and a height or thickness defined by a z dimension extending in a z direction.

9. An aerosol- generating article according to claim 8 in which an air flow path is defined through the aerosol-forming substrate, for example in which a low resistance air flow path is defined through the substrate, for example in which the aerosol-forming substrate has a resistance to draw (RTD), along the air flow path, of less than 30 millimetre H₂O.

10. An aerosol-generating article according to any preceding claim in which a radius of curvature of the aerosol-forming substrate at an innermost portion of the roll is less than 4 times the thickness of the aerosol-forming substrate, and/or in which a radius of curvature of the aerosol-forming substrate at an innermost portion of the roll is between 2 millimetres and 30 millimetres.

11. An aerosol-generating article according to any preceding claim in which the aerosolforming substrate is rolled onto a spool.

12. An aerosol- generating article according to any preceding claim in which the roll of aerosolforming substrate is located within a casing, for example a substantially cylindrical casing.

13. An aerosol- generating article according to any preceding claim comprising a plurality of perforations or sprocket holes for tensioning the aerosol-forming substrate.

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

15. An aerosol-generating system according to claim 14 in which the aerosol-generating device comprises a heater and a tensioning mechanism for applying tension to the aerosolforming substrate of the aerosol-forming article, such that the aerosol-forming substrate can be unrolled from the aerosol-generating article for use.