Improved aerosol-generating article with a porous layer

Abstract

An aerosol-generating article (200, 390, 400, 900, 1000, 1100, 1200, 1300) for use with an aerosol-generating device (300) to form an inhalable aerosol. The aerosol-generating article comprises an aerosol-forming substrate (210, 410, 910), the aerosol-forming substrate having a base defined by x- and y-dimensions, and a height defined by a z-dimension. The planar lower surface of the aerosol-forming substrate is defined by the base, and the planar upper surface of the aerosol-forming substrate is parallel to the planar lower surface. The aerosol-generating article further comprises a first layer configured to protect the planar upper surface and a second layer configured to protect the planar lower surface. The first layer is a breathable layer.

Description

[Technical Field]

[0001] The present disclosure relates to aerosol-generating articles. The present disclosure also relates to aerosol-generating devices and aerosol-generating systems. [Background technology]

[0002] A typical aerosol-generating system may include an aerosol-generating device and an aerosol-generating article. The aerosol-generating device may include a heating element, and the aerosol-generating article may include an aerosol-forming substrate. In use, the heating element of the aerosol-generating device heats the aerosol-forming substrate of the aerosol-generating article, causing an aerosol to be emitted from the aerosol-forming substrate. The aerosol can be inhaled by a user.

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

[0004] Studies have shown that in such typical aerosol-generating articles, a large portion of the plug of the aerosol-forming substrate may not be heated sufficiently to form an aerosol during use. This is undesirable because this portion of the plug of the aerosol-forming substrate contributes to the costs of manufacturing and shipping the aerosol-generating article but does not contribute to the aerosol delivered to the end user. This may be true regardless of the method by which the aerosol-forming substrate is heated, for example, whether a resistance heater or an induction heater is used, and regardless of whether the plug of the aerosol-forming substrate is heated from the inside or the outside. Summary of the Invention [Problem to be solved by the invention]

[0005] It is an object of the present invention to provide an aerosol-generating article in which a substantial portion of the aerosol-forming substrate of the aerosol-generating article is heated sufficiently during use to form an aerosol. [Means for solving the problem]

[0006] According to the present disclosure, there is provided an aerosol-generating article for use with an aerosol-generating device to form an inhalable aerosol. The aerosol-generating article may include an aerosol-forming substrate. The aerosol-forming substrate may have a base. The base may be defined by an x-dimension and a y-dimension. The aerosol-forming substrate may have a height. The height may be defined by a z-dimension.

[0007] Thus, according to a first aspect of the present disclosure, there is provided an aerosol-generating article for use with an aerosol-generating device to form an inhalable aerosol. The aerosol-generating article comprises an aerosol-forming substrate having a base defined by an x-dimension and a y-dimension. The aerosol-forming substrate has a height defined by a z-dimension. The x-, y-, and z-dimensions may extend in the x-, y-, and z-directions, respectively. The x-, y-, and z-directions may all be perpendicular to one another. Preferably, the planar lower surface of the aerosol-forming substrate is defined by the base, and the planar upper surface of the aerosol-forming substrate is parallel to the planar lower surface. The aerosol-generating article further comprises a first layer configured to protect the planar upper surface and a second layer configured to protect the planar lower surface, at least the first layer being a breathable layer. Thus, an aerosol-generating article for use with an aerosol-generating device to form an inhalable aerosol may comprise an aerosol-forming substrate having a base defined by x and y dimensions and a height defined by a z dimension, wherein the planar lower surface of the aerosol-forming substrate is defined by the base and the planar upper surface of the aerosol-forming substrate is parallel to the planar lower surface, and wherein the aerosol-generating article further comprises a first layer configured to protect the planar upper surface and a second layer configured to protect the planar lower surface, wherein at least the first layer is a breathable layer.

[0008] The x and y dimensions may be greater than the z dimension. The aerosol-forming substrate may be, or may be described as, a planar or flat substrate. A planar or flat substrate may be a volume of a substrate having two predominantly planar sides that are greater in area than the remaining sides that make up the volume of the substrate. That is, the x and y dimensions of a planar or flat substrate are preferably greater than the z dimension of the substrate.

[0009] Aerosol-generating devices use various heating systems, such as resistance or induction heating elements. The heating elements may be arranged in physical contact with the aerosol-forming substrate. Rod-shaped aerosol-forming substrates may be heated externally by a heating element arranged around the rod or internally by a heating element arranged through the rod. However, with rod-shaped aerosol-forming substrates, a large portion of the substrate may not be heated sufficiently to aerosolize the volatile components of the aerosol-forming substrate, resulting in a portion of the substrate being wasted. An advantageous solution to wasted aerosol-forming substrates is to use a substantially planar substrate, as defined herein, as a consumable. For example, in a system in which a planar consumable is arranged in association with a planar heater in an aerosol-generating device, substantially all of the aerosol-forming substrate can be heated to a temperature sufficient to form an aerosol, thereby reducing or eliminating waste. This is achieved due to the high surface-to-volume ratio of planar substrates, which allows the entire substrate to reach a suitable aerosol-forming temperature by heating one or both sides of the planar surface.

[0010] Aerosol-generating articles formed from aerosol-forming substrates, such as planar aerosol-forming substrates, are preferably shaped to allow for easy user manipulation. Users may need to handle and manipulate the articles to remove them from their packaging and to load and unload them from the aerosol-generating device. Aerosol-generating articles formed from planar substrates can be conveniently stacked and packaged, with adjacent articles coming into contact with each other. Furthermore, various articles with different flavors or other properties can be stacked on top of each other during use to customize the user experience. These desirable properties of aerosol-generating articles can also create several problems. For example, a user's hands may become contaminated when handling the articles. Furthermore, there is a risk of contamination of other articles or of adjacent articles sticking together during packaging. It has also been observed that many aerosol-forming substrates produce liquid slurries when heated, and such slurries can contaminate aerosol-generating devices. These problems may be alleviated if the aerosol-generating article comprises a first layer configured to protect the planar upper surface and a second layer configured to protect the planar lower surface, and at least the first layer is a breathable layer.

[0011] The first and second layers may help minimize contact between the user and the aerosol-forming substrate, thereby minimizing contamination of the user's hands during handling of the aerosol-generating article. The first and second layers may also help minimize contamination between adjacent articles and further help prevent adhesion between adjacent articles when packaged.

[0012] The aerosol-generating article is preferably heated from below, for example, by a planar heater disposed in contact with the base of the article. Optimally, most of the gaseous components generated by heating the aerosol-forming substrate migrate toward the upper surface of the aerosol-forming substrate and are released from the upper surface into the airflow to form an aerosol. Because the first layer is a breathable layer, these gaseous components can be released from the upper surface of the aerosol-generating article.

[0013] As used herein with respect to the present invention, the term "breathable" refers to the ability of a material to allow air to pass through the material.

[0014] Optionally, the first layer is configured to cover the upper planar surface and the second layer is configured to cover the lower planar surface, with the greater coverage providing greater protection by the first and second layers.

[0015] The first and second layers may be formed of the same material. Thus, both the first and second layers may be breathable. The gas component may be emitted from both planar surfaces of the aerosol-forming substrate, and the breathable layer may also help prevent adhesion and retain the slurry that forms during use.

[0016] The first layer is or includes a porous material. The porous material may cover at least one surface of the aerosol-forming substrate. Optionally, the porous material completely encases the aerosol-forming substrate. Optionally, the porous material is porous paper or a porous mesh. In this context, the term "porous" is used to mean sufficiently porous that the aerosol formed by the aerosol-forming substrate during use can escape through the porous layer. The porous material may have a total outer surface area. At least 20, 50, 80, or 90 percent of the total outer surface area may be open, for example, to expose the substrate to the external environment or to allow aerosol from the substrate to pass through, or both. The porous material may be or include a mesh.

[0017] The porous material may be or include a nonwoven fabric.

[0018] The porous material may include a binder. The binder may include a cross-linked copolymer. The binder may include a butyl acrylate-ethyl acrylate copolymer.

[0019] The porous material may comprise one or more materials selected from cellulose, viscose, and polyethylene terephthalate.

[0020] The porous material may include a plurality of pores. The plurality of pores in the porous material may each have a diameter of 10 micrometers to 100 micrometers. The average pore size may be 10 micrometers to 100 micrometers, for example, 20 micrometers to 50 micrometers, preferably 22 micrometers to 31 micrometers. The pores can provide a highly uniform porosity occupying about 45% to 70%, for example, about 55% to 65% of the surface of the porous material. As used herein, micrometer and micron have the same meaning and may be used interchangeably.

[0021] The porous material may have a thickness of 35 micrometers to 85 micrometers, for example, 55 micrometers to 70 micrometers. The porous material may have a density of about 10 to 35 grams per square meter (gsm or g / m 2 ), for example, may have a basis weight of about 19 to 28 gsm.

[0022] The porous material is approximately 20x10 -5 m / s~25x10 -5 It may have an average permeability of m / s.

[0023] Advantageously, the porous material is compostable, for example fully compostable according to standard number EN13432.

[0024] The porous material may be a commercially available tea bag material.

[0025] The first layer and the second layer may be embossed layers. The thickness of the embossed layer, including the embossing, may be up to 1.7 mm, for example, 0.8 mm to 1.7 mm, for example, 1.1 mm to 1.5 mm. However, the thickness of the embossed layer may be much thinner, for example, 100 to 200 micrometers.

[0026] Alternatively, the first and second layers may be formed from different materials having different properties, such as different porosities. For example, it may be desirable for the porosity or breathability of the first layer to be greater than the porosity or breathability of the second layer.

[0027] The second layer may be a water-impermeable layer, for example, a water-impermeable layer configured to prevent water from leaking through the base of the aerosol-generating article when the article is heated. The slurry produced by the aerosol-forming substrate upon heating contains water, and the water-impermeable layer helps to retain this slurry within the aerosol-generating article. This can significantly reduce contamination of the aerosol-generating device used to heat the aerosol-generating article.

[0028] Optionally, the first layer comprises or consists of a filtering material, such as a paper or polymer having a high density of micro-perforations configured to allow the passage of gas, e.g., air. The first layer may comprise or consist of a porous or breathable material having a basis weight of 7 to 30 grams per square meter (gsm), e.g., 10 to 25 gsm.

[0029] The first layer has an air permeability of 75 to 190 cm at a pressure of 200 Pa. 3 / cm 2 / s, e.g., 95 to 170 cm at 200 Pa 3 / cm 2 The first layer may comprise or consist of a porous or breathable material having a wet burst strength of 350 mm water column or greater. The first layer may comprise or consist of a porous or breathable material having a machine direction tensile strength of 0.045 kN / m or greater. The first layer may have a thickness of 5 microns to 150 microns, for example, 10 microns to 70 microns. The first layer may comprise a plurality of pores, with an average pore size of 10 microns to 150 microns. The first layer may be formed from a composite or laminate material.

[0030] The first layer is preferably formed from a material that is readily available and easy to handle. Manufacture of the aerosol-generating article preferably involves bulk processing of a continuous sheet of material from which the first layer will be formed. There are many commercially available candidates for materials from which to form the first layer. Preferably, the first layer is formed from a food-grade filtration layer, such as tea bag material.

[0031] The first layer may be made of a heat resistant material, for example, the porous material forming the first layer may be a material that is heat resistant to at least 200 degrees Celsius, optionally at least 220 degrees Celsius, optionally at least 240 degrees Celsius, optionally at least 260 degrees Celsius, or optionally at least 280 degrees Celsius.

[0032] As used herein with respect to the present invention, the term "heat resistant" means a material that does not undergo substantial thermal degradation or decomposition when exposed to a specified temperature range.

[0033] The first layer may comprise a material that is heat resistant up to at least the operating temperature of the aerosol-generating article when heated during use. In other words, the first layer may comprise a material that does not thermally degrade or decompose at the operating temperature of the aerosol-generating article when heated during use. The first layer may be substantially resistant to thermal degradation at temperatures typically reached during use of an aerosol-generating system including the aerosol-generating article. This may prevent the production of undesirable thermal decomposition products from the aerosol-forming article.

[0034] Optionally, the second layer comprises or consists of a water-impermeable plastic or foil. The second layer may be a laminated layer comprising an inner layer and a water-impermeable outer layer. The outer layer may prevent the slurry from escaping from the aerosol-generating article during use, while the inner layer may function to facilitate the transfer of gaseous components and may also act to retain the slurry. The inner layer may be the same material as the first layer or a different breathable material. The inner layer may be configured to absorb or retain the slurry generated by the aerosol-forming substrate upon heating. The inner layer may be a paper layer.

[0035] The outer layer is preferably a thermally conductive layer, such as a metal foil layer. The outer layer may be an aluminum foil layer. The second layer may be a laminated layer, such as a laminated layer having an outer layer formed from aluminum foil and an inner layer formed from paper or tea bag material.

[0036] Optionally, one or more peripheral surfaces of the aerosol-generating article are covered with a protective layer, e.g., a protective layer of the same material as the first layer or the same material as the second layer. Optionally, the entire aerosol-forming substrate is enveloped in a protective layer, e.g., a layer of the same material as the first layer.

[0037] Optionally, at least one of the first and second layers, and possibly both the first and second layers, includes printed indicia, such as an identification mark or an orientation mark. Thus, each aerosol-generating article may be visibly marked to provide information about the article, e.g., the type, flavor, or brand of substrate. If the first and second layers have different properties, orientation marks may be provided to clearly distinguish the top and bottom surfaces of the article.

[0038] Optionally, at least one of the first and second layers, and optionally both the first and second layers, may comprise a heat or thermochromic indicator configured to indicate whether the aerosol-generating article has been heated above a predetermined temperature. For example, the first layer heat or thermochromic indicator may comprise or consist of citric acid. An indicator that indicates when the aerosol-generating article has been heated above a predetermined temperature has the advantage that it can be used to distinguish used articles from unused articles. Preferably, the indicator undergoes a visible change when heated to a temperature above room temperature and below the optimal heating temperature for the aerosol-generating article, e.g., between 100°C and 400°C, e.g., between 150°C and 350°C.

[0039] Optionally, at least one of the first and second layers, and in some cases both the first and second layers, may include an embossed layer, e.g., an embossed layer that creates a 10-50 micron texture above or below the plane of the layer. The textured layer may be used to create a visible symbol, e.g., a brand logo. The embossed layer may also be altered or removed during use of the article. For example, if the aerosol-generating article is pressed into an aerosol-generating device during use, the embossed layer may be flattened and therefore altered. This indicia can be used to distinguish between articles inserted into an aerosol-generating device and those not inserted, potentially providing a way to identify used articles.

[0040] In some embodiments, the x dimension may be 80% to 120%, or 90% to 110% of the y dimension. Optionally, the x dimension is approximately the same as the y dimension.

[0041] Optionally, the base is substantially planar. The base may define the lower surface of the substrate, or may be referred to as the lower surface. The base may define the substantially planar lower surface of the aerosol-forming substrate. Advantageously, a planar base or planar lower surface may allow for better thermal contact with a planar heater of the aerosol-generating device.

[0042] Optionally, one or both of the aerosol-forming substrate and the aerosol-generating article are three-dimensional shapes that can be described as tablet-shaped, coin-shaped, disc-shaped, or cylindrical, e.g., right cylinder-shaped or right circular cylinder-shaped.

[0043] Optionally, one or both of the x and y dimensions are at least three times larger than the z dimension. Optionally, one or both of the x and y dimensions are at least 3.5 times larger than the z dimension. Optionally, one or both of the x and y dimensions are at least four times larger than the z dimension. For example, one or both of the x and y dimensions are at least 4.5 times larger than the z dimension, or 5 times larger than the z dimension, or 5.5 times larger than the z dimension, or 6 times larger than the z dimension.

[0044] Advantageously, a larger base area may provide a larger surface area for heating by the planar heater of the aerosol-generating device. Advantageously, a smaller height may result in a smaller temperature gradient or difference across the height of the substrate during heating. For example, if the base of the substrate is heated in contact with the planar heater, a smaller spacing or height between the base and the top surface may result in a smaller temperature difference between the base and the top surface opposite the base. Advantageously, this may allow a larger portion of the substrate to be heated to a temperature at which an aerosol will be emitted, while minimizing the risk of burning the hottest portion of the substrate closest to the heater. Alternatively, or in addition, this may reduce the time required to heat the substrate sufficiently to emit an aerosol.

[0045] Optionally, the aerosol-forming substrate has the shape of a cylinder, e.g., a right cylinder or a right circular cylinder, defined by a base and a height. Optionally, the base is circular or substantially circular. Advantageously, the symmetry of the circular base may allow the substrate to be inserted into the corresponding circular recess of the device in any orientation. This may reduce the user's effort to insert the substrate into the device. This may be particularly important for substrates with a relatively low height, e.g., less than 20, 10, or 8 mm. As will be understood by those skilled in the art, in this context, the term orientation may be used to refer to the rotational direction of the substrate around the z-direction.

[0046] When the base is circular or substantially circular, it may have a diameter. The diameter may be equal to the x and y dimensions. The diameter may be three times larger than the z dimension or height. The diameter may be 3.5 times larger than the z dimension or height. The diameter may be four times larger than the z dimension or height, for example, five times larger, 5.5 times larger, or six times larger than the z dimension or height. When the substrate is a right cylinder, the area of ​​the base is equal to the area of ​​the curved surface when the diameter is four times larger than the height or z dimension of the substrate. Thus, when the diameter is more than four times the height, the area of ​​the base will be larger than the area of ​​the curved surface, and it may be more efficient to heat the base, for example, using a planar heater, than to heat the curved surface.

[0047] Optionally, the base is defined by its two-dimensional shape. This two-dimensional shape may form the lower surface of the aerosol-forming substrate. Optionally, the aerosol-forming substrate has an upper surface. Optionally, the upper surface of the aerosol-forming substrate is defined by an upper two-dimensional shape, which may be the same shape as the base two-dimensional shape. The upper surface may be spaced apart from the base by a height. The upper surface may face in an opposite direction from the base. The base and upper surface, which may also be referred to as the lower surface, may both be planar and lie on parallel planes spaced apart by a height, if desired. Optionally, the aerosol-forming substrate has one or both of a substantially circular lower surface and a substantially circular upper surface.

[0048] Optionally, the base or lower surface is defined by a first two-dimensional shape having a base perimeter. Optionally, the upper surface is defined by a second two-dimensional shape having an upper surface perimeter. One or more peripheral surfaces may optionally extend perpendicularly between the lower and upper surfaces. One or more peripheral surfaces may be defined between the perimeters of the first and second two-dimensional shapes, and optionally, the perimeter of the first shape is the same as the perimeter of the second shape.

[0049] Optionally, the aerosol-forming substrate has a substantially planar lower surface. Optionally, the aerosol-forming substrate has a substantially planar upper surface. Advantageously, a planar surface may allow better thermal contact with the planar heater.

[0050] Optionally, the ratio of the largest of the x and y dimensions to the z dimension is from 3:1 to 25:1, such as from 4:1 to 20:1, for example from 4.2:1 to 10:1, for example from 4.5:1 to 8:1. If the base is circular or substantially circular, optionally the ratio of the diameter of the base (e.g., defined by the x dimension or the y dimension) to the z dimension is from 4:1 to 20:1, for example from 4.2:1 to 10:1, for example from 4.5:1 to 8:1. Optionally, the ratio of the radius of the base (e.g., defined by half the x dimension or half the y dimension) to the z dimension is from 2:1 to 10:1, for example from 2.1:1 to 5:1, for example from 2.25:1 to 4:1. Advantageously, these ratios are determined by at least the following four factors:

[0051] a base surface area for heating that may increase with the x and y dimensions;

[0052] the temperature difference across the height of the substrate, which may increase with the z-dimension if heated at one or both of the base and top surface;

[0053] the structural stiffness of the substrate or article, which for substrates having x and y dimensions that are more than four times the z dimension, may decrease with the x and y dimensions for a given z dimension, and may increase with the z dimension for a given x and y dimension;

[0054] It may provide a compromise between the ability of the substrate to generate a sufficient amount of aerosol to satisfy the user, which may increase with the x, y, and z dimensions.

[0055] Optionally, the aerosol-forming substrate has an upper surface and a lower surface, as described above, and one or both of the upper and lower surfaces is a circular or elliptical or polygonal two-dimensional shape, for example a polygonal shape selected from the list consisting of a triangle, square, rectangle, pentagon, hexagon, heptagon, octagon, nonagon and decagon.

[0056] Optionally, one or both of the x and y dimensions are between 10 mm and 50 mm, such as between 12 mm and 30 mm, for example between 14 mm and 26 mm, for example between 16 mm and 24 mm, for example between 18 mm and 22 mm, for example about 18 mm, or about 19 mm, or about 20 mm, or about 21 mm, or about 22 mm.

[0057] Optionally, the aerosol-forming substrate is in the form of a cylinder defined by a circular base and a height, the diameter of the base being from 10 mm to 50 mm, for example from 12 mm to 30 mm, such as from 14 mm to 26 mm, for example from 16 mm to 24 mm, for example from 18 mm to 22 mm, for example about 18 mm, or about 19 mm, or about 20 mm, or about 21 mm, or about 22 mm.

[0058] Optionally, the z dimension is between 1 mm and 5 mm, such as between 1.2 mm and 4.5 mm, for example between 1.4 mm and 4 mm, for example between 1.6 mm and 3.5 mm, for example between 1.7 mm and 3 mm, for example about 1.7 mm, or about 1.8 mm, or about 1.9 mm, or about 2 mm, or about 2.1 mm.

[0059] If desired, the aerosol-forming substrate is in the form of a cylinder defined by a base and a height, the height being from 1 mm to 5 mm, such as from 1.2 mm to 4.5 mm, for example from 1.4 mm to 4 mm, for example from 1.6 mm to 3.5 mm, for example from 1.7 mm to 3 mm, for example about 1.7 mm, or about 1.8 mm, or about 1.9 mm, or about 2 mm, or about 2.1 mm.

[0060] Preferably the height or z dimension is less than 20mm, such as less than 10mm, for example less than 8mm.

[0061] The aerosol-forming substrate is particularly preferably in the form of a cylinder, for example a right cylinder, defined by a base and a height, the diameter of the base being 10 mm to 50 mm, preferably 14 mm to 50 mm, and the height being 1 mm to 5 mm, preferably 1 mm to 4 mm.

[0062] Advantageously, the dimensions described in the paragraph above may provide a compromise between the four factors described above, depending on the ratio between the x, y, and z dimensions.

[0063] If desired, the article consists entirely of the aerosol-forming substrate, which may advantageously result in one or more of the following benefits: reduced manufacturing costs for the article, reduced weight of the article and therefore reduced shipping costs, and reduced waste from manufacturing or use of the article.

[0064] The aerosol-forming substrate may comprise an aerosol-forming material. Optionally, the aerosol-forming substrate consists entirely of an aerosol-forming material. Optionally, the aerosol-forming substrate comprises one or both of nicotine and tobacco. The aerosol-forming substrate may be substantially homogeneous. Optionally, the aerosol-forming substrate comprises or consists of tobacco material, for example homogenized tobacco material. Optionally, the aerosol-forming substrate comprises or consists of a solid aerosol-forming material. Optionally, the aerosol-forming substrate comprises or consists of a liquid aerosol-forming material held within a porous matrix. Optionally, the aerosol-forming substrate comprises or consists of a gel aerosol-forming material.

[0065] Optionally, a first portion of the aerosol-forming substrate comprises a first aerosol-forming material. Optionally, a second portion of the aerosol-forming substrate comprises a second aerosol-forming material. The second aerosol-forming material may be different from the first aerosol-forming material. Advantageously, a substrate having two different aerosol-forming materials may allow for combinations of aerosol-forming materials that may not otherwise be available. This may enable, for example, flavor combinations that enhance the user experience.

[0066] Optionally, one or both of the first aerosol-forming material and the second aerosol-forming material comprise one or both of tobacco and nicotine. Optionally, one or both of the first aerosol-forming material and the second aerosol-forming material are substantially homogeneous. Optionally, one or both of the first aerosol-forming material and the second aerosol-forming material comprise or consist of a solid aerosol-forming material. Optionally, one or both of the first aerosol-forming material and the second aerosol-forming material comprise or consist of a liquid aerosol-forming material held within a porous matrix. Optionally, one or both of the first aerosol-forming material and the second aerosol-forming material comprise or consist of a gel aerosol-forming material.

[0067] Optionally, one or both of the first aerosol-forming material and the second aerosol-forming material extend through the height or z-dimension of the aerosol-forming substrate, for example, through the entire height or z-dimension of the aerosol-forming substrate. Optionally, one or both of the first aerosol-forming material and the second aerosol-forming material extend through the entire height or z-dimension of the aerosol-forming substrate, from the base of the substrate to the top surface of the substrate.

[0068] Optionally, the first portion, or first aerosol-forming material, occupies an inner portion of the base or substrate. Optionally, the second portion, or second aerosol-forming material, occupies a peripheral portion of the base or substrate. Optionally, the peripheral portion at least partially surrounds the inner portion. The inner portion may or may not include a radially central portion of the base. Thus, the first aerosol-forming material can be shaped as a circular cylinder, e.g., a right cylinder, located at the radially central portion of the base, or as an annular cylinder, e.g., a right annular cylinder, located around the radially central portion of the base, and the second aerosol-forming material can be shaped as an annular cylinder, e.g., a right annular cylinder, at least partially surrounding the first aerosol-forming material.

[0069] Optionally, the first portion, or first aerosol-forming material, occupies a radially inner or central portion of the base. Optionally, the second portion, or second aerosol-forming material, occupies a radially peripheral portion of the base at least partially surrounding the inner or central portion. For example, optionally, the first aerosol-forming material is shaped as a circular cylinder located at the radially central portion of the base or as an annular cylinder located around the radially central portion of the base, and the second aerosol-forming material is shaped as an annular cylinder at least partially surrounding the first aerosol-forming material.

[0070] Advantageously, the arrangement described in the above two paragraphs can mean that the orientation of the substrate is not important when the base of the substrate is in thermal contact with the substrate, similar to a planar heater having an inner or central heating portion and an outer heating portion. Regardless of the orientation, the first aerosol-forming material will be in thermal contact with the inner or central heating portion, and the second aerosol-forming material will be in thermal contact with the outer heating portion. This is not the case, for example, with a cylindrical substrate in which the first aerosol-forming material occupies the left half of the substrate and the second aerosol-forming material occupies the right half of the substrate. As one skilled in the art will understand, in this context, the term orientation may be used to refer to the direction of rotation of the substrate around the z-direction.

[0071] Thus, according to a particularly preferred embodiment of the first aspect of the present disclosure, there is provided an aerosol-generating article for use with an aerosol-generating device to form an inhalable aerosol. The aerosol-generating article comprises an aerosol-forming substrate, the aerosol-forming substrate having a base defined by x and y dimensions, and a height defined by z dimension. The aerosol-generating article further comprises a first layer configured to protect the upper planar surface of the aerosol-forming substrate, and a second layer configured to protect the lower planar surface of the aerosol-forming substrate, with at least the first layer preferably being breathable.

[0072] A first portion of the aerosol-forming substrate comprises a first aerosol-forming material, and a second portion of the aerosol-forming substrate comprises a second aerosol-forming material different from the first aerosol-forming material. The first aerosol-forming material occupies an interior portion of the base, and the second aerosol-forming material occupies a peripheral portion of the base at least partially surrounding the interior portion. As one skilled in the art would understand after reading this disclosure, the features described herein can be applicable to either or both of the first aspect and this particularly preferred embodiment of the first aspect.

[0073] The first portion of the substrate may occupy a volume that is 25 to 400, 25 to 200, 25 to 100, or 25 to 50 percent of the volume of the second portion of the substrate. All of the first aerosol-forming material of the substrate may occupy a volume that is 25 to 400, 25 to 200, 25 to 100, or 25 to 50 percent of the volume of all of the second aerosol-forming material of the substrate.

[0074] Any one, two, or all of the aerosol-forming material, the first aerosol-forming material, and the second aerosol-forming material may include one or more organic materials, such as tobacco. Any one, two, or all of the aerosol-forming material, the first aerosol-forming material, and the second aerosol-forming material may include one or more of herb leaves, tobacco leaves, tobacco vein fragments, reconstituted tobacco, homogenized tobacco, extruded tobacco, and expanded tobacco.

[0075] Any one, two, or all of the aerosol-forming material, the first aerosol-forming material, and the second aerosol-forming material may comprise one or more aerosol formers. Suitable aerosol formers are well known in the art and include, but are not limited to, one or more aerosol formers selected from polyhydric alcohols (such as propylene glycol, polyethylene glycol, triethylene glycol, 1,3-butanediol, and glycerin), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids (such as dimethyl dodecanedioate and dimethyl tetradecanedioate). It may be particularly preferred that the aerosol former is or comprises glycerin.

[0076] Any one, two, or all of the aerosol-forming material, the first aerosol-forming material, and the second aerosol-forming material may comprise at least 1, 2, 5, 10, or 15 weight percent aerosol former.

[0077] Any one, two, or all of the aerosol-forming material, the first aerosol-forming material, and the second aerosol-forming material may include nicotine. Any one, two, or all of the aerosol-forming material, the first aerosol-forming material, and the second aerosol-forming material may include 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), and cannabicitran (CBT). Preferably, the cannabinoid compound is CBD or THC. It may be particularly preferred that the cannabinoid compound is CBD.

[0078] Any one, two, or all of the aerosol-forming material, the first aerosol-forming material, and the second aerosol-forming material may include one or more flavoring agents. The one or more flavoring agents may include 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 one or more herbaceous materials. Suitable herbaceous materials include herb leaves or other herbaceous materials from herbaceous plants, including, but not limited to, mint (such as peppermint and spearmint), lemon balm, basil, cinnamon, lemon basil, chives, coriander, lavender, sage, tea, thyme, and caraway. The one or more flavoring agents may include tobacco materials.

[0079] Optionally, the aerosol-forming substrate comprises an opening. The opening may extend through the entire height, or z-dimension, of the substrate. The opening may be located in a substantially central portion, e.g., a radially central portion, of the substrate. Thus, the opening may be referred to as a radially central through-hole. Advantageously, the opening may help accommodate thermal expansion of the substrate during use. This can minimize deformation of the substrate, which may cause poor thermal contact with the planar heater if the substrate deforms and bends or compresses away from the planar heater. Furthermore, advantageously, the opening can form an airflow path through the substrate. This can aid in aerosol generation or entrainment of the aerosol in the airflow through or passing through the substrate.

[0080] The openings may have a maximum cross-sectional dimension, e.g., a maximum dimension in the x or y direction, of at least 1, 2, 3, 5, or 10 mm. The openings may have a maximum cross-sectional dimension, e.g., a maximum dimension in the x or y direction, of no more than 20 or 10 mm. The openings may have a minimum cross-sectional dimension, e.g., a minimum dimension in the x or y direction, of at least 1, 2, 3, 5, or 10 mm. The openings may have a minimum cross-sectional dimension, e.g., a minimum dimension in the x or y direction, of no more than 20 or 10 mm. Advantageously, these sizes may provide a compromise between adequately accommodating thermal expansion of the substrate and airflow through the substrate, while still allowing the substrate to contain enough aerosol-forming material to form sufficient aerosol to satisfy a user.

[0081] Optionally, the first aerosol-forming material is a first homogenized tobacco material. Optionally, the second aerosol-forming material is a second homogenized tobacco material having a different composition than the first homogenized tobacco material.

[0082] Optionally, the first homogenized tobacco material differs from the second tobacco composition by having at least one difference selected from the list consisting of a different aerosol former content, a different tobacco content, a different flavorant content, a different moisture content, and a different nicotine content.

[0083] Optionally, the plurality of holes or notches are defined in the top surface of the aerosol-forming substrate. Optionally, the plurality of holes or notches are defined in the base or bottom surface of the aerosol-forming substrate. Optionally, at least some of the plurality of holes are blind holes that do not penetrate the entire height or z-dimension of the aerosol-forming substrate. Optionally, at least some of the plurality of holes are through-holes that extend through the entire height or z-dimension of the aerosol-forming substrate, for example, from the top surface to the base.

[0084] Optionally, the aerosol-generating article is substantially symmetrical with respect to a plane extending in the x and y dimensions through a position midway between the base and the top surface. Optionally, the base and top surface of the aerosol-generating article are substantially indistinguishable. Optionally, the base and top surface of the aerosol-generating article are interchangeable, for example, in the sense that substantially the same aerosol is emitted from heating the base of the substrate and from turning the article upside down and heating the top surface of the substrate (now considered the new base). Optionally, both the base and top surface of the aerosol-generating article are equally suitable for heating by a heater, for example, a planar heater. Advantageously, this can allow a user to insert the article into the cavity of an aerosol generating device without having to worry about the article being upside down.

[0085] The aerosol-forming substrate may be manufactured by any suitable process. For example, a slurry containing the components of the aerosol-forming material and additional water may be formed. The slurry may be cast and dried to form a sheet of the aerosol-forming material, which is then cut into shape.

[0086] Aerosol-forming substrates made of multiple materials can be formed in a similar manner. For example, a first slurry containing the components of a first aerosol-forming material and additional water can be formed. A second slurry containing the components of a second aerosol-forming material and additional water can be formed. These first and second slurries can be cast and dried to form sheets of the first and second aerosol-forming materials.

[0087] The sheet of the first aerosol-forming material may then be cut and shaped into a long right cylinder. The sheet of the second aerosol-forming material may then be wrapped around the long right cylinder of the first aerosol-forming material to form a long right cylinder having a central portion of the first aerosol-forming material and an outer portion of the second aerosol-forming material. This long cylinder may then be cut at several locations along its curved surface. This results in the formation of a plurality of aerosol-forming substrates in the shape of short right cylinders, each having an inner central portion of the first aerosol-forming material and an outer peripheral portion of the second aerosol-forming material surrounding the first aerosol-forming material.

[0088] Alternatively, a short right cylinder may be punched out of a sheet of a first aerosol-forming material. A short right annular cylinder may be punched out of a sheet of a second aerosol-forming material. The short right cylinder of the first aerosol-forming material may then be disposed within the central hole of the short right annular cylinder of the second aerosol-forming material. This results in the formation of an aerosol-forming substrate that is shaped like a right circle, has a height equal to the thickness of the sheets of first and second aerosol-forming materials, and has an inner central portion of the first aerosol-forming material and an outer peripheral portion of the second aerosol-forming material surrounding the first aerosol-forming material.

[0089] Alternatively, aerosol-forming substrates can be produced using well-known extrusion processes. For example, a stiff slurry of aerosol-forming material can be placed in an extruder and extruded through an extrusion head to form an elongated extrudate. The elongated extrudate is then preferably dried, for example, by passing through a continuous drying oven, and sliced ​​to form individual aerosol-forming substrates. Two-material aerosol-forming substrates can be formed in a similar manner using two extruders and a single dual extrusion head. Such systems are well known for producing multi-material extrudates. For example, a first aerosol-forming material can be placed in a first extruder and fed through a first die of a dual extruder head. Simultaneously, a second aerosol-forming material can be placed in a second extruder and fed through a second die of the dual extruder head. The resulting extrudate can be in the shape of a continuous cylinder having an inner portion of the first aerosol-forming material and an outer portion of the second aerosol-forming material. This continuous cylinder may then be dried and cut at multiple locations to form multiple slices of aerosol-forming material, which may have surfaces coated with the porous material or may be completely surrounded by the porous material to form an aerosol-forming substrate according to the present disclosure, such as an aerosol-forming substrate according to a preferred embodiment of the first aspect.

[0090] According to the present disclosure, there is provided an aerosol generating device for heating an aerosol-generating article to form an aerosol. The aerosol generating device may comprise a cavity for accommodating at least a portion of, for example the entire, the aerosol-generating article. The aerosol generating device may comprise a heater for heating the aerosol-forming article, for example the aerosol-forming substrate of the aerosol-generating article. The heater may be arranged to heat the base of the cavity. The base of the cavity may be dimensioned to receive the aerosol-generating article, as described above, for example the base of the aerosol-generating article according to the first aspect.

[0091] Thus, according to a second aspect of the present disclosure, there is provided an aerosol generating device for heating an aerosol-generating article to form an aerosol, the aerosol generating device comprising a cavity for accommodating at least part of, for example the entire, of the aerosol-generating article, and a heater for heating the aerosol-generating article.

[0092] The heater is preferably arranged to supply heat to the base of the cavity, which is preferably dimensioned to accommodate the base of an aerosol-generating article according to the first aspect.

[0093] Advantageously, the heater is preferably arranged to supply heat to the base of the cavity, which is preferably dimensioned to accommodate the base of an aerosol-generating article according to the first aspect. This can therefore be a particularly efficient heating arrangement, particularly where the base area of ​​the substrate is large, for example larger than the curved surface area.

[0094] Optionally, the heater is a planar heater. Optionally, the base of the well is substantially planar. Advantageously, a planar heater or base may provide good thermal contact with the planar surface of the aerosol-forming substrate.

[0095] The heater can be disposed at or below the base of the cavity.

[0096] Optionally, the heater comprises a first portion configured to heat a first portion of the base of the cavity and a second portion configured to heat a second portion of the base of the cavity. Optionally, the first portion of the heater is configured to heat an inner portion of the base of the cavity. The second portion of the heater may be configured to heat a peripheral portion of the base of the cavity. The peripheral portion may at least partially surround the inner portion of the base of the cavity. The inner portion may be or include a central portion of the base of the cavity. The inner portion may be substantially circular in cross section or shape, or may be substantially annular in cross section or shape. The peripheral portion may be substantially annular in cross section or shape.

[0097] Optionally, the first heater portion is configured to heat a radially central portion of the base of the depression. Optionally, the second heater portion is configured to heat a radially peripheral portion of the base of the depression at least partially surrounding the radially central portion of the base of the depression, e.g., the first heater portion is configured to heat a radially central circular portion of the base of the depression and the second heater portion is configured to heat an annular portion of the base of the depression surrounding the central portion of the base of the depression.

[0098] Advantageously, the above-described arrangement of the first and second heater parts can mean that the first and second heater parts contact the same part of the aerosol-forming substrate in use, regardless of the orientation of the device of the aerosol-forming substrate when inserted into the device cavity. As a person skilled in the art will appreciate, in this context the term orientation may be used to refer to the direction of rotation of the substrate around the z-direction.

[0099] If desired, the first heater portion and the second heater portion are configured to operate independently of each other, for example to independently heat respective portions of the base of the depression, which may advantageously enable the first and second heater portions to heat the first and second portions of the aerosol-forming substrate to different temperatures, or for different times, or to different temperatures for different times.

[0100] Optionally, the first heater portion and the second heater portion are configured to operate simultaneously to heat respective portions of the base of the cavity, which may advantageously enable the first and second heater portions to heat first and second portions of the aerosol-forming substrate simultaneously.

[0101] If desired, the first heater portion and the second heater portion are configured to heat respective portions of the base of the depression, e.g., the first and second portions, to different temperatures. Advantageously, this may enable the first and second heater portions to heat the first and second portions of the aerosol-forming substrate to temperatures specifically optimized for the first and second portions of the aerosol-forming substrate. For example, the first portion of the aerosol-forming substrate may emit an optimized aerosol at a first temperature, while the second portion of the aerosol-forming substrate may be different from the first aerosol-forming substrate and thus emit the optimized aerosol at a second temperature different from the first temperature. Thus, in this case, the first heater portion and the second heater portion configured to heat the first and second portions of the base of the depression to different temperatures may be able to emit an optimized aerosol from both the first and second portions of the aerosol-forming substrate.

[0102] Optionally, the heater is or comprises a resistive heater. Optionally, one or both of the first heater portion and the second heater portion is or comprises a resistive heater.

[0103] Optionally, the heater is or comprises an induction heater. Optionally, one or both of the first heater portion and the second heater portion are or comprise an induction heater. The induction heater may comprise one or both of a susceptor and an inductor.

[0104] The aerosol generating device may comprise a device body. The device body may comprise a heater. The aerosol generating device may comprise a mouthpiece element. The device body may comprise a device body housing. The device body housing may define a recess for accommodating at least a portion of the aerosol-generating article. The device body and the mouthpiece element may be removably connectable. The mouthpiece element may be removably connectable to the device body, e.g., the device body housing.

[0105] The mouthpiece element may be removably coupleable with the device body, e.g., the device body housing, between a coupled position and a detached position. In the coupled position, the cavity may be at least partially covered, e.g., by the mouthpiece element. In the detached position, the cavity may be at least partially exposed, e.g., to allow for insertion of an article into the cavity. The mouthpiece element may be movable, e.g., pivotable about a hinge, relative to the device body, e.g., between a first position and a second position. In the first position, the cavity may be at least partially covered, e.g., by the mouthpiece element. In the second position, the cavity may be at least partially exposed, e.g., to allow for insertion of an article into the cavity. Advantageously, covering the cavity or the article within the cavity may ensure that most aerosol from the article reaches the user along a desired flow path rather than leaking into the external environment.

[0106] The device, e.g., the device body, may include a power source, e.g., a battery. In use, the power source can provide power to the heater. The device, e.g., the device body, may include a controller. The controller may be configured to control power from the power source to the heater.

[0107] The device body may have a distal end and a proximal end. The recess may be defined in the proximal end of the device body. The mouthpiece element has a proximal end and a distal end. The distal end of the mouthpiece element may be configured to removably couple to the proximal end of the device body.

[0108] The mouthpiece element, or at least a portion of the mouthpiece element, can be configured to be inserted into a user's mouth. A proximal end of the mouthpiece element may be configured to be inserted into a user's mouth.

[0109] The aerosol generating device may include a second heater. The device body may include a second heater. The mouthpiece element may include a second heater.

[0110] The power supply may be configured to provide power to the second heater, and the controller may control power from the power supply to the second heater.

[0111] When the mouthpiece element includes a second heater and the device body includes a power source, the mouthpiece element may be movable relative to or connectable to the device body to electrically connect the device body's power source to the second heater. For example, the device body may include device body electrical contacts connected to the power source, and the mouthpiece element may include mouthpiece element electrical contacts connected to the second heater. Also, when the mouthpiece element is moved to a particular position relative to or connected to the device body, the device body electrical contacts may come into contact with the mouthpiece element electrical contacts to electrically connect the power source to the second heater.

[0112] The second heater may be configured to contact, or provide heat to, or both contact and provide heat to, one or both of the top and side surfaces of the aerosol-generating article or aerosol-forming substrate in use.

[0113] The device, e.g., a mouthpiece element or the device body of the device, may have a second surface. The second surface may be a second heating surface. The second heater may have a second surface or may be configured to provide heat to the second surface. The second surface may be configured to contact, provide heat to, or both contact and provide heat to one or both of the top and side surfaces of the aerosol-generating article or aerosol-forming substrate during use. Thus, if desired, the device may be configured to provide heat to both the base of the recess and the second surface. Advantageously, this may allow both the base and the top or side surface of the aerosol-generating article or aerosol-forming substrate to be heated. This may allow a large portion of the substrate to be heated to a temperature at which an aerosol is released, while minimizing the risk of burning the hottest portion of the substrate closest to the heater or second heater. Alternatively, or in addition, this may reduce the time required to heat the substrate sufficiently to release an aerosol.

[0114] The second surface may be configured to push the aerosol-generating article toward the base of the cavity during use. The aerosol-generating system may be configured such that when the article is at least partially, e.g., completely, contained within the cavity of the device, the second surface of the device pushes or urges the article toward the base of the cavity of the device. When the device moves from the second or disconnected position to the first or connected position, the second surface may contact the article or substrate and, if necessary, push against the article or substrate, e.g., contact or push against the upper surface of the article or substrate. Advantageously, this pushing may help to ensure good thermal contact between the base of the aerosol-forming substrate and the base of the cavity of the device. Furthermore, if the second surface is heated, e.g., by a second heater, or is part of a second heater during use, this pushing may help to ensure good thermal contact between the second heating surface and the upper surface of the aerosol-forming substrate.

[0115] In use, the second surface may form a ceiling of the cavity. Where the mouthpiece element comprises a second surface, the second surface may be configured to form a ceiling of the cavity when the mouthpiece is coupled to the device body. Where the mouthpiece element comprises a second surface, the second surface may form a ceiling of the cavity when the mouthpiece is coupled to the device body.

[0116] The second heater, or second surface, may be located adjacent to or at least partially within a portion of the device body housing, thereby forming a ceiling of a cavity, if desired, for example, when a mouthpiece element is coupled to the device body.

[0117] If the mouthpiece element includes a second surface or a second heater, the mouthpiece element can be coupled to the device body so that the second surface or second heater is located adjacent to or at least partially within a portion of the device body housing, where appropriate, thereby forming a ceiling of the recess.

[0118] One or both of the second surface and the second heater may be planar. Advantageously, a planar second heater or a planar second surface provides good thermal contact with the planar surface of the substrate to be heated.

[0119] The second surface may face the base of the recess, for example, when the mouthpiece element is coupled to the device body. The second heater may face the device body, for example, when the mouthpiece element is coupled to the device body. The plane of the second heater may face the plane of the heater. The recess may be located between the heater and the second heater, for example, between the plane of the heater and the plane of the second heater.

[0120] The spacing between the base and the second surface, e.g., between the plane of the base and the plane of the second surface, can be sufficient to accommodate the height or z-dimension of the aerosol-generating article. This spacing may be present when the mouthpiece element is coupled to the device body. This spacing may be present when the device is in, for example, the first position or coupled position of the device, but not in the second position or the uncoupled position of the device. This spacing may be at least 50, 60, 70, 80, or 90 percent of the z-dimension of the aerosol-generating article before being contained within the recess. This spacing may be no greater than 200, 150, 120, or 110 percent of the z-dimension of the aerosol-generating article before being contained within the recess. This spacing may be 50% to 200%, preferably 50% to 150%, and more preferably 80% to 120%, of the z-dimension of the aerosol-generating article before being contained within the recess. As one skilled in the art will appreciate, the z-dimension of an article may be smaller when compressed, e.g., when contained within a recess between the base and the second surface. Advantageously, in use, the heater may heat the base of the article and the second heater may heat the top surface of the article, which may advantageously allow the majority of the substrate to be heated to a temperature at which the aerosol is emitted, while minimizing the risk of burning the hottest part of the substrate nearest the heater or second heater.

[0121] Features described in relation to the heater may also be applied to the second heater, in particular features described in relation to the first and second heater portions of the heater may also be applicable to the first and second heater portions of the second heater.

[0122] Therefore, if desired, the second heater is a planar heater. Advantageously, a planar heater may provide good thermal contact with the planar surface of the aerosol-forming substrate.

[0123] The second heater may be disposed on or adjacent to the second surface, or below the second surface.

[0124] Optionally, the second heater comprises a first portion configured to heat a first portion of the second surface and a second portion configured to heat a second portion of the second surface. Optionally, the first portion of the second heater is configured to heat an inner portion of the second surface. The second portion of the second heater may be configured to heat a peripheral portion of the second surface. The peripheral portion may at least partially surround the inner portion. The inner portion may be or include a central portion of the second surface. The inner portion may be substantially circular in cross section or shape, or may be substantially annular in cross section or shape. The peripheral portion may be substantially annular in cross section or shape.

[0125] Optionally, the first portion of the second heater is configured to heat a radially central portion of the second surface. Optionally, the second portion of the heater is configured to heat a radially peripheral portion of the second surface at least partially surrounding the radially central portion of the second surface, e.g., the first portion of the second heater is configured to heat a radially central circular portion of the second heated surface and the second portion of the second heater is configured to heat an annular portion of the second surface surrounding the radially central portion of the second surface.

[0126] Advantageously, the above-described arrangement of the first and second portions of the second heater can mean that, in use, the first and second portions of the second heater heat the same portion of the upper surface of the aerosol-forming substrate, regardless of the orientation of the aerosol-forming substrate when inserted into the cavity of the device. As a person skilled in the art will appreciate, in this context the term orientation may be used to refer to the direction of rotation of the substrate around the z-direction.

[0127] If desired, the first and second heater portions of the second heater are configured to operate independently of each other, for example to independently heat respective portions of the base of the recess, which may advantageously enable the first and second heater portions of the second heater to heat the first and second portions of the aerosol-forming substrate to different temperatures, or for different times, or to different temperatures for different times.

[0128] Optionally, the first heater portion and the second heater portion of the second heater are configured to operate simultaneously to heat respective portions of the second surface, which may advantageously enable the first and second heater portions of the second heater to heat the first and second portions of the aerosol-forming substrate simultaneously.

[0129] Optionally, the first heater portion and the second heater portion of the second heater are configured to heat respective portions of the second surface, e.g., the first and second portions, to different temperatures. Advantageously, this may enable the first and second heater portions of the second heater to heat the first and second portions of the aerosol-forming substrate to temperatures specifically optimized for the first and second portions of the aerosol-forming substrate. For example, the first portion of the aerosol-forming substrate may emit an optimized aerosol at a first temperature, while the second portion of the aerosol-forming substrate may be different from the first aerosol-forming substrate and thus emit the optimized aerosol at a second temperature different from the first temperature. Thus, in this case, the first heater portion and the second heater portion of the second heater configured to heat the first and second portions of the second surface to different temperatures may be able to emit an optimized aerosol from both the first and second portions of the aerosol-forming substrate.

[0130] Optionally, the second heater is or comprises a resistive heater. Optionally, one or both of the first heater portion and the second heater portion of the second heater are or comprise a resistive heater.

[0131] Optionally, the second heater is or comprises an induction heater. Optionally, one or both of the first heater portion and the second heater portion of the second heater are or comprise an induction heater. The induction heater may comprise one or both of a susceptor and an inductor.

[0132] The device, e.g., the device body, may include one or more peripheral walls around the recess. These one or more peripheral walls may extend from the base. These one or more peripheral walls may extend from the base at least partially to the second surface, e.g., when the mouthpiece element is coupled to the device body.

[0133] The device may comprise a third heater. The device body may comprise a third heater. The mouthpiece element may comprise a third heater. The third heater may comprise, or be configured to provide heat to, one or more peripheral walls around the cavity. Advantageously, the third heater may be able to heat the side surfaces between the base and the top surface of the aerosol-generating article.

[0134] Optionally, the third heater is or comprises a resistance heater. Optionally, the third heater is or comprises an induction heater. The induction heater may comprise one or both of a susceptor and an inductor.

[0135] The second heater, or second surface, may be located adjacent to or at least partially within one or more peripheral walls around the cavity, thereby forming a roof of the cavity, as desired, for example, when the mouthpiece element is coupled to the device body. If the mouthpiece element comprises a second surface or second heater, the mouthpiece element may be connectable to the device body such that the second surface or second heater is located adjacent to or at least partially within one or more peripheral walls around the cavity, thereby forming a roof of the cavity, as desired.

[0136] The device, e.g., one or both of the device body and the mouthpiece element, may include an air inlet. The device, e.g., the mouthpiece element, may include an air outlet. The device may include an airflow path that fluidly connects the air inlet to the air outlet. The airflow path may extend through one or both of the recess and through the recess. Thus, in use, the device may be configured such that when negative pressure is applied to the air outlet, e.g., by a user sucking on the air outlet, air is drawn through the air inlet and then through the aerosol-generating article contained within the recess, thereby entraining aerosol emitted from the aerosol-forming substrate of the article and exiting through the air outlet.

[0137] According to the present disclosure, there is provided an aerosol generating system. The system may comprise an aerosol generating article, for example an aerosol generating article as described above, for example an aerosol generating article according to the first aspect. The system may comprise an aerosol generating device, for example an aerosol generating device as described above, for example an aerosol generating device according to the second aspect.

[0138] Thus, according to a third aspect of the present invention there is provided an aerosol generating system comprising an aerosol-generating article according to the first aspect and an aerosol generating device according to the second aspect.

[0139] As described above, the aerosol generation device may comprise a device body and a mouthpiece element, which may be movable relative to one another, e.g., removably connectable, and thus the device body and mouthpiece element may have a first or connected position and a second or disconnected position.

[0140] As used herein, the term "aerosol-generating article" may refer to an article that is capable of generating or emitting an aerosol.

[0141] The term "aerosol-forming substrate" as used herein may refer to a substrate capable of emitting an aerosol or volatile compound capable of forming an aerosol. Such a volatile compound may be emitted by heating the aerosol-forming substrate. The aerosol-forming substrate may comprise an aerosol-forming material. The aerosol-forming substrate may be adsorbed, coated, impregnated, or loaded onto a carrier or support. The aerosol-forming substrate may conveniently be part of an aerosol-generating article or a smoking article.

[0142] As used herein, the term "aerosol-generating device" may refer to a device used in conjunction with an aerosol-generating article to enable the generation or emission of an aerosol.

[0143] As used herein, the term "aerosol former" may refer to any suitable known compound or mixture of compounds that, upon use, facilitates the formation of an aerosol. The aerosol may be a dense and stable aerosol. The aerosol may be substantially resistant to thermal decomposition at the operating temperature of the aerosol-forming substrate or aerosol-generating article. [Brief explanation of the drawings]

[0144] [Figure 1] 1 illustrates an aerosol generating system comprising an aerosol-generating article and an aerosol generating device for use with the aerosol-generating article. [Figure 2] 2 shows the aerosol generation system of FIG. 1 in a loaded and coupled position. [Figure 3] FIG. 1 is a schematic diagram of a portion of an aerosol-generating device showing a planar aerosol-forming substrate being heated by a planar heater. [Figure 4] FIG. 1 is an exploded view of an aerosol-generating article. [Figure 5] FIG. 5 is a plan view of the aerosol-generating article of FIG. 4. [Figure 6] FIG. 5 is a bottom plan view of the aerosol-generating article of FIG. 4. [Figure 7] FIG. 5 is a cross-sectional view of the aerosol-generating article of FIG. 4. [Figure 8] FIG. 1 is an exploded view of another aerosol-generating article. [Figure 9] FIG. 9 is a cross-sectional view of the aerosol-generating article of FIG. 8. [Figure 10] FIG. 2 is a cross-sectional view of another aerosol-generating article. [Figure 11] FIG. 1 is a plan view of an aerosol-generating article. [Figure 12] FIG. 1 is a plan view of an aerosol-generating article. [Figure 13] FIG. 1 is a plan view of an aerosol-generating article. [Figure 14] FIG. 14 is another plan view of the aerosol-generating article of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0145] The embodiments will now be further described with reference to the figures.

[0146] Figure 1 shows an aerosol generation system 100 comprising an aerosol-generating article 200 and an aerosol generating device 300 for use with the aerosol-generating article 200. Figure 2 shows the same system 100 in a loaded and coupled position.

[0147] The aerosol-generating article 200 is used in conjunction with an aerosol-generating device 300 to form an inhalable aerosol. The aerosol-generating article 200 comprises an aerosol-forming substrate 210 and has a circular right cylindrical shape.

[0148] Substrate 210 has a planar circular base 212 and a planar circular top surface 213, each having a diameter, which may be referred to as the x or y dimension of substrate 210, that is approximately 20 mm. Substrate 210 has a height, which may be referred to as the z dimension of substrate 210, extending from base 212 to top surface 213, of approximately 3 mm. The top surface of the substrate is covered with a thin layer of a porous first material (not visible in FIG. 1), and the base of the substrate is covered with a non-porous second material (not visible in FIG. 1).

[0149] The aerosol-forming substrate 210 comprises a first portion 214 of a first aerosol-forming material and a second portion 216 of a second aerosol-forming material different from the first aerosol-forming material. The first aerosol-forming material is a first homogenized tobacco material, and the second aerosol-forming material is a second homogenized tobacco material having a different composition from the first homogenized tobacco material. The first homogenized tobacco material differs from the second tobacco composition by having a different flavorant content. Specifically, the first homogenized tobacco material has a menthol flavorant uniformly dispersed throughout, whereas the second homogenized tobacco material does not. As one skilled in the art would understand, the first homogenized tobacco material can differ from the second tobacco composition in many ways, for example, by having at least one difference selected from a different aerosol-forming material content, a different tobacco content, a different flavorant content, a different moisture content, and a different nicotine content.

[0150] For illustrative purposes, the composition of a suitable aerosol-forming material, which may be the second aerosol-forming material in the specific embodiment described above, may be as follows: Percentages are given in weight percent relative to the final product. The second aerosol-forming material may be a second homogenized tobacco material having a moisture content of about 5-25%, preferably about 7-15%, in the final product. Such a material may be used, for example, as the second portion 216 of the aerosol-forming substrate 210 described above. The second aerosol-forming material may further include: 1. Tobacco leaf; for example, a tobacco leaf blend containing about 15-45%, preferably about 20-35%, of at least one of the following tobacco leaf types: bright tobacco leaf, dark tobacco leaf, and aromatic tobacco leaf. The tobacco material is ground and graded to a particle size of about 100-380 mesh, preferably about 170-320 mesh. 2. Cellulose fibers; for example, about 1 to 15%, preferably about 3 to 7%, of cellulose fibers having a length of about 10 to 250 μm, preferably about 10 to 120 μm. 3. Tobacco fiber, for example about 5-20%, preferably about 7-15%, of any tobacco type or blend of tobacco types as a filler. The tobacco fiber is preferably derived from stems and / or petioles graded into fibers of about 10-350 μm, preferably about 10-180 μm in length. 4. Binder: for example, about 1-10%, preferably about 1-5%, of a binder such as any of the common gums or pectins used in the food and beverage (F&B) industry. Preferred binders may include natural pectins, such as fruit pectins, e.g., citrus pectins, or tobacco pectins; guar gum, land locust bean gum, e.g., hydroxyethyl and / or hydroxypropyl versions of these gums; starches, e.g., modified or derivatized starches; alginates; methylcellulose, ethylcellulose, ethylhydroxymethylcellulose, and carboxymethylcellulose; dextran; and xanthan gum. A preferred binder is guar. 5. Aerosol formers, e.g., about 5-35%, preferably about 10-25%, of an aerosol former. Suitable aerosol formers known in the art include glycerin; monohydric alcohols such as menthol, polyhydric alcohols such as triethylene glycol; esters of polyhydric alcohols such as glycerol monoacetate, glycerol diacetate, or glycerol triacetate; and aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids, e.g., their dimethyl esters.

[0151] "Tobacco type" means one of various types of tobacco, for example, based on different curing processes that are performed on the tobacco before it is further processed into tobacco products.

[0152] Examples of bright tobaccos include Brazilian Fulcure, Indian Fulcure, Chinese Fulcure, American Fulcure, e.g., Virginia tobacco, and Tanzanian Fulcure.

[0153] Examples of aromatic tobaccos include Turkish Oriental, Greek Oriental, and Semi-Oriental tobaccos, but also fire-cured, US Burley, and varieties such as Perique and Rustica.

[0154] Examples of dark tobaccos include dark-cured Brazil Galpao, Burley Malawi or other African Burley, Sun-cured or air-cured Indonesian Kastri.

[0155] For illustrative purposes, the composition of another aerosol-forming material that may be suitable as the first aerosol-forming material in the specific embodiment above may be as follows: Percentages are given in weight percent relative to the final product. The first aerosol-forming material may be used primarily for flavoring purposes and may be suitable as the first portion 214 of the aerosol-forming substrate 210 described above. The first aerosol-forming material may include: 1. An aerosol former, such as glycerin; for example, about 10-40%, preferably about 20-30%. 2. Organic fiber: any suitable plant variety commonly available on the market with a purity of, for example, about 10% to 30%, preferably about 15% to 25%, that meets the applicable FDA F&B grade requirements. For example, organic fiber may be obtained from cellulose, cotton, wood, or tea plant varieties as by-products or by-processing waste from the F&B tea industry. The organic fiber preferably has a length of about 10 to 400 μm, and more preferably about 10 to 200 μm. 3. Organic vegetable glycerides; for example, about 15 to 55%, preferably about 20 to 35%, of plants such as clove, echinacea, fennel, ginger, hawthorn berry, elderberry, monarda, mullein leaf, nettle, plantain, turmeric, yarrow, and complexes thereof. 4. Organic plant extracts; for example, about 1% to 15%, preferably 2% to 7%, of menthol (dl-menthol, CHO, 2-isopropyl-5-methylcyclohexanol) obtained from any of the aforementioned plants, as well as Chaerophyllum macrospermum, Mesosphaerum sidifolium, or other related plant varieties, and p-menthone-3-ol as an optional secondary alcohol as a diastereoisomer of 5-methyl-2-(propan-2-yl)cyclohexan-1-ol.

[0156] Alternatively, such aerosol-forming materials may contain about 0.5 to 5%, preferably about 1 to 3%, of plant essential oils, such as palm, coconut, and wood-derived essential oils.

[0157] The aerosol-forming substrate may be formed from a first aerosol-forming material and a second aerosol-forming material using a well-known coaxial extrusion process. For example, the first aerosol-forming material may be placed in a first extruder and fed through a first central die of a dual extruder head. Simultaneously, the second aerosol-forming material may be placed in a second extruder and fed through a second outer die of the dual extruder head. The resulting extrudate may be in the shape of a continuous cylinder having an inner portion of the first aerosol-forming material and an outer portion of the second aerosol-forming material. This continuous cylinder may then be dried, for example, by passing through a continuous infrared drying oven, and cut at multiple locations to form multiple slices of the aerosol-forming material. These slices of the aerosol-forming material may be laid on or pressed into a breathable material, such as a sheet of tea bag paper, and a first side of each slice of the aerosol-forming material may be coated with the breathable material. The slices may be further dried to incorporate the breathable material. If desired, another layer of breathable material may be applied to the top surface of the slice. Each slice may be completely wrapped in breathable material, which, once coated, may be trimmed as needed to form an aerosol-forming substrate having a central first portion 214 of a first aerosol-forming material, a radially outer second portion 216 of a second aerosol-forming material, and a breathable layer covering at least one of the upper and lower surfaces.

[0158] First portion 214 and second portion 216 extend through the entire height of base 210. First portion 214 is a right cylinder and occupies a radially central portion of base 210. Second portion 216 is annular and occupies a radially peripheral portion of base 210 surrounding the central portion. The outer diameter of second portion 216 is approximately twice the outer diameter of first portion 214.

[0159] The aerosol-forming substrate 210 comprises a plurality of notches (not visible in FIG. 1) in its upper surface 213, which do not extend through the entire height of the substrate 210. The aerosol-forming substrate 210 also comprises a plurality of through-holes (not visible in FIG. 1) that extend from the upper surface 213, through the entire height of the substrate 210, to the base 212 of the substrate 210.

[0160] The aerosol generating device 300 comprises a mouthpiece element 310 and a device body 320 that are removably connectable to one another. As will be appreciated by those skilled in the art, this removably connection can be facilitated by any suitable means, for example, a magnetic connection, a snap-fit ​​connection, or a threaded connection.

[0161] The device body 320 comprises a device body housing 322 defining a substantially right cylindrical cavity 324 for receiving the aerosol-generating article 200. The device body 320 further comprises a power source 326 and a controller 328. The device body 320 further comprises a heater 330 configured to provide heat to a substantially circular, planar base 332 of the cavity 324.

[0162] Heater 330 is a planar heater disposed below base 332 of recess 324. Heater 330 has a substantially circular cross-section and includes a first heater portion and a second heater portion. The first heater portion is a circular radially central portion of heater 330, and the second heater portion is an annular radially peripheral portion of heater 330 surrounding the first heater portion. The first heater portion is configured to heat the circular radially central portion of base 332 of recess 324, and the second heater portion is configured to heat the annular radially peripheral portion of base 332 of recess 324 surrounding the circular radially central portion of base 332 of recess 324.

[0163] The first heater portion and the second heater portion are configured to operate independently of each other. That is, the controller 328 can separately control the power supply to the first heater portion and the second heater portion. This allows the first and second portions of the base 332 of the cavity 324 to be heated separately. If desired, the first heater portion and the second heater portion can be operated simultaneously to heat the first and second portions of the base 332 of the cavity 324 simultaneously.

[0164] The first heater portion and the second heater portion are configured to heat the respective portions of the base 332 of the recess 324 to different temperatures, thereby heating the first portion 214 and the second portion 216 of the aerosol-forming substrate 210 to different temperatures. Specifically, the first heater portion is configured to heat the first portion of the base 332 of the recess 324 to approximately 180 degrees Celsius, and the second heater portion is configured to heat the second portion of the base 332 of the recess 324 to approximately 140 degrees Celsius. It is believed that these two different temperatures result in optimal aerosol emission from the two different aerosol-forming materials of the first portion 214 and the second portion 216 of the substrate 210.

[0165] In this embodiment, heater 330 is a resistive heater. That is, heater 330 is an electrical resistance heater. The first heater section comprises an electrical resistive track disposed on a circular substrate. The second heater section comprises an electrical resistive track disposed on an annular substrate surrounding the circular substrate. However, those skilled in the art will understand that the heater may also be an induction heater, for example, a heater comprising a susceptor and an inductor.

[0166] The mouthpiece element 310 includes an air inlet 312 and an air outlet 314. The air inlet 312 and the air outlet 314 are in fluid communication with each other by an air flow path within the mouthpiece element 310.

[0167] In use, the aerosol-generating article 200 is received in the recess 324 of the device body 320 with the top surface facing upward. The mouthpiece element 310 is then coupled to the device body 320. This is considered the loaded coupled position of the aerosol generation system 100. When the mouthpiece element 310 is coupled to the device body 320, the second surface 316 of the mouthpiece element 310 is pressed into contact with the top surface 213 of the base 210. This pressing urges the base 210 towards the base 332 of the recess 324, thereby ensuring good thermal contact between the base of the article and the base 332 of the recess 324.

[0168] Figure 2 shows the aerosol generation system 100 of Figure 1 in a loaded and coupled position, in which the system 100 is ready for use.

[0169] In use, a user may insert the proximal end of mouthpiece element 310, which includes air outlet 314, into their mouth. The user may then press and hold a button (not shown) on device body 320 and inhale on air outlet 314.

[0170] In response to the button being pressed, controller 328 supplies power from power supply 326 to heater 330. Specifically, controller 328 supplies power from power supply 326 to a first heater segment, followed by a short delay to supply power to a second heater segment. This delay allows the first and second heater segments to reach their optimal temperatures of 180°C and 140°C approximately simultaneously. Device body 320 further includes temperature sensors (not shown) for monitoring the temperatures of the first and second heater segments of heater 330 while the button is being pressed. Once the first and second heater segments of heater 330 reach their optimal temperatures, controller 328 controls the supply of power to heater 330 based on feedback from the temperature sensors to maintain the heater segments at or near their optimal temperatures.

[0171] Supplying power to the first and second heater portions causes the first and second heater portions to heat the first and second portions of the base 332 of the recess 324, thereby heating the first portion 214 and the second portion 216 of the substrate 210 so as to emit the first and second aerosols through the porous first layer of the article.

[0172] By drawing on the air outlet 314, air is drawn through the air inlet 312 of the mouthpiece element 310 and throughout the article. This airflow entrains the aerosol emitted from the substrate 210. The airflow and entrained aerosol are then drawn out through the air outlet 314 and delivered to the user. The airflow through the device 300 is indicated by arrows in FIG. 2.

[0173] When the user is finished inhaling the air outlet 314, the user may release the button. Releasing the end of the button causes the controller 328 to stop providing power from the power supply 326 to the heater 330.

[0174] The user may repeat the sucking or puffing process until satisfied, or until they determine that the article 200 is consumed. The user may then detach the mouthpiece element 310 from the device body 320 and discard the article 200. The device can then be reused with another aerosol-generating article.

[0175] 3 is a schematic diagram of a portion of an aerosol-generating device in which a planar aerosol-generating article 390 comprising an aerosol-forming substrate is heated by a planar heater 3100. The underside 301 of the article 390 rests on the top surface of the heater. When the substrate is heated, volatile components of the substrate (e.g., glycerin, water, nicotine) are volatilized into gases and vapors 3200, which are emitted from the top surface 302 of the article 390. The device is configured so that air drawn into the device by a user flows along an airflow path 3300 past the top surface 302 of the article 390. The volatile components 3200 emitted from the substrate are entrained in this airflow and condense to form an aerosol, which can be inhaled by a user 350.

[0176] FIG. 4 shows an exploded view of a specific embodiment of an aerosol-generating article 400. The article 400 is circular and cylindrical, measuring 20 mm in diameter and 3 mm thick. The article comprises an aerosol-forming substrate 410, a breathable upper layer 420, and a water-impermeable lower layer 430. The substrate may be formed from or contain any suitable aerosol-forming material, such as homogenized tobacco. FIG. 5 shows a top view of the article 400, showing the breathable layer 410 covering the upper surface of the aerosol-forming substrate 410. FIG. 6 shows a bottom plan view of the article 400, showing the water-impermeable layer 430 covering the lower surface of the aerosol-forming substrate 410. FIG. 6 is a schematic cross-sectional view of the article 400 of FIGS. 5 and 6, illustrating the layered structure of the breathable layer 420, the aerosol-forming substrate 410, and the water-impermeable layer 430.

[0177] In a specific embodiment, breathable layer 420 may be a suitable porous material, such as commercially available tea bag material. Breathable layer 420 may have a thickness of approximately 25 microns.

[0178] In a specific embodiment, the water impermeable layer may be a metal or polymer film, such as an aluminum foil layer. The thickness of the water impermeable layer 430 may be 50 microns.

[0179] In a particular embodiment, the aerosol-forming substrate 410 may be a tobacco-containing substrate, such as homogenized tobacco. The aerosol-forming substrate forms the majority of the 3 mm thickness of the aerosol-generating article 400.

[0180] The layered structure can be formed by any suitable manufacturing method. For example, homogenized tobacco can be cast to the desired thickness onto a continuous sheet of aluminum foil, and a continuous sheet of tea bag material placed on top. The resulting laminated sheet can then be dried and cut to shape to form individual aerosol-generating articles.

[0181] FIG. 9 shows an exploded view of another specific embodiment of an aerosol-generating article 900. The article 900 is circular and cylindrical, with a diameter of 15 mm and a thickness of 2 mm. The article comprises an aerosol-forming substrate 910, a breathable upper layer 920, and a water-impermeable lower layer 9302. The substrates may be formed from or include any suitable aerosol-forming material, for example, homogenized tobacco. The upper layer 920 may be tea bag material, and the lower layer 9302 may be aluminum. A further layer 9301 of porous or absorbent material is sandwiched between the aerosol-forming substrate 910 and the lower layer 9302. The further layer may function to contain and absorb the slurry generated by heating the aerosol-forming substrate 920. The further layer may be formed from the same material as the upper layer, for example, tea bag material.

[0182] Figure 10 is a cross-sectional view of another specific embodiment of an aerosol-generating article 1000. The embodiment of Figure 10 is identical to the embodiment of Figure 9, except that the peripheral surface of the aerosol-generating article is covered by a layer of porous material 1025. This porous material 1025 is the same breathable material as the top layer 920 described in connection with Figure 9.

[0183] 11 is a plan view of another specific embodiment of an aerosol-forming article 1100 showing a breathable top layer 1120. Visible indicia 1190 can be printed on top surface 1120 and serve to provide information to a user, for example, identifying the flavor of article 1100 or the orientation of the article.

[0184] FIG. 12 is a plan view of another specific embodiment of an aerosol-forming article 1200 showing a breathable top layer 1220. Visible indicia 1290 are formed on the top surface 1220 by an embossing technique. The embossing process results in a texture with raised features of approximately 0.01 to 0.05 mm, which is sufficient to create a noticeable visual effect. The embossed effect may disappear if the article 1200 is compressed, for example, during use. Thus, the embossed indicia can provide a way to distinguish used from unused articles.

[0185] Figure 13 is a plan view of another specific embodiment of an aerosol-forming article 1300 showing a breathable top layer 1320. Indicia 1390 is printed on top surface 1320 using a heat indicator, for example, a heat-reactive dye. Figure 14 is a plan view of the same aerosol-generating article after heating in an aerosol-generating device. Indicia 1390 is altered by heating to provide a visual indication that article 1300 has been used.

[0186] For purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like are understood to be modified in all instances by the term "about." Also, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically recited herein. Accordingly, in this context, the number A is understood as A ± 10%. Within this context, the number A may be considered to include a numerical value that is within the typical standard error for measurement of the property that the number A modifies. In some instances, as used in the appended claims, the number A may deviate by the percentages recited above, provided that the amount by which A deviates does not materially affect the basic and novel characteristics of the claimed invention. Also, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically recited herein. [Example]

[0187] The present invention is defined in the claims. However, below 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 any other example, embodiment, or aspect described herein.

[0188] Example 1 1. An aerosol-generating article for use with an aerosol-generating device to form an inhalable aerosol, the aerosol-generating article comprising an aerosol-forming substrate having a base defined by x and y dimensions and a height defined by a z dimension, a planar lower surface of the aerosol-forming substrate defined by the base, and a planar upper surface of the aerosol-forming substrate that is parallel to the planar lower surface, the aerosol-generating article further comprising a first layer configured to protect the planar upper surface and a second layer configured to protect the planar lower surface, at least the first layer being a breathable layer. Example 2. 10. The aerosol-generating article of Example 1, wherein the first layer is configured to cover the planar upper surface and the second layer is configured to cover the planar lower surface. Example 3 3. The aerosol-generating article of claim 1 or 2, wherein the first layer and the second layer are formed from the same material. Example 4. 3. The aerosol-generating article of any one of claims 1 to 2, wherein the first and second layers are formed from different materials having different properties, such as different porosities. Example 5. An aerosol-generating article as described in Example 4, wherein the second layer is a water-impermeable layer, for example, a water-impermeable layer configured to prevent water from leaking through the base of the aerosol-generating article when the article is heated. Example 6 6. An aerosol-generating article according to any one of Examples 1 to 5, wherein the first layer comprises or consists of a filtering material, such as a paper or polymer having a high density of micro-perforations configured to allow the passage of a gas, such as air. Example 6A. 7. An aerosol-generating article according to any one of Examples 1 to 6, wherein the first layer comprises, or consists of, a porous or breathable material having a basis weight of 7 to 35 grams per square meter (gsm), for example 10 to 30 gsm, for example 19 to 28 gsm, for example about 25 gsm. Example 6B. The first layer has an air permeability of 75 to 190 cm at a pressure of 200 Pa. 3 / cm 2 / s, e.g., 95 to 170 cm at 200 Pa 3 / cm 2 10. An aerosol-generating article according to any one of Examples 1 to 6A, comprising or consisting of a porous or breathable material, wherein the porous or breathable material is / s. Example 6C. An aerosol-generating article according to any one of Examples 1 to 6B, wherein the first layer comprises or consists of a porous or breathable material having a wet burst strength of at least 350 mm of water. Example 6D. An aerosol-generating article according to any one of Examples 1 to 6C, wherein the first layer comprises, or consists of, a porous or breathable material having a machine direction tensile strength of 0.045 kN / m or greater. Example 7 The aerosol-generating article of any of Examples 1 to 6D, wherein the first layer has a thickness of from 5 microns to 150 microns, such as from 10 microns to 85 microns, for example from 35 microns to 70 microns. Example 8 8. An aerosol-generating article according to any one of Examples 1 to 7, wherein the first layer comprises a plurality of pores, the average pore size being between 10 microns and 150 microns, for example between 20 microns and 50 microns, for example between 22 microns and 31 microns. Example 9. An aerosol-generating article according to any one of Examples 1 to 8, wherein the first layer is formed from a food-grade filtration layer, such as tea bag material. Example 10. 10. An aerosol-generating article according to any one of Examples 1 to 9, wherein the second layer comprises or consists of a water-impermeable plastic or foil. Example 11 An aerosol-generating article according to any one of Examples 1 to 10, wherein the second layer is a laminated layer comprising an inner layer and a water-impermeable outer layer. Example 12 The aerosol-generating article of Example 11, wherein the inner layer is the same material as the first layer. Example 13 13. The aerosol-generating article of any one of claims 11 to 12, wherein the inner layer is configured to absorb or retain a slurry generated by the aerosol-forming substrate upon heating. Example 14. 14. The aerosol-generating article of any one of Examples 11, 12, and 13, wherein the inner layer is a paper layer. Example 15. 15. An aerosol-generating article according to any one of Examples 11 to 14, wherein the outer layer is a thermally conductive layer, such as a metal foil layer, for example an aluminum foil layer. Example 15A. 16. The aerosol-generating article of any one of Examples 1 to 15, wherein at least one of the first layer and the second layer includes printed indicia, such as an identification mark or an orientation mark. Example 16. An aerosol-generating article described in any of Examples 1 to 15A, wherein at least one of the first layer and the second layer comprises a thermal indicator or a thermochromic indicator configured to indicate whether the aerosol-generating article has been heated above a predetermined temperature. Example 16A. 17. The aerosol-generating article of Example 16, wherein the thermal indicator or thermochromic indicator of the first layer comprises or consists of citric acid. Example 17. An aerosol-generating article as described in any of Examples 1 to 16, wherein at least one of the first layer and the second layer comprises an embossed layer, for example, the embossed layer providing a texture of 10 to 50 microns above or below the plane of the layer. Example 18. An aerosol-generating article according to any one of Examples 1 to 17, wherein the largest of the x and y dimensions is equal to or greater than the z dimension, for example, at least twice the z dimension, or at least three times the z dimension, or at least four times the z dimension. Example 19. An aerosol-generating article according to any one of Examples 1 to 18, wherein the x dimension is approximately the same as the y dimension. Example 20. An aerosol-generating article according to any one of Examples 1 to 19, wherein the base is substantially planar. Example 21. An aerosol-generating article according to any one of Examples 1 to 20, wherein the aerosol-forming substrate and / or the aerosol-generating article is in the form of a three-dimensional shape that may be described as tablet-shaped, coin-shaped, disc-shaped, or cylindrical. Example 22. 1. An aerosol-generating article for use with an aerosol-generating device to form an inhalable aerosol, the aerosol-generating article comprising an aerosol-forming substrate comprising an aerosol-forming material; An aerosol-generating article according to any one of Examples 1 to 21, wherein the aerosol-forming substrate has a three-dimensional shape having a base defined by an x ​​dimension and a y dimension and a height defined by a z dimension, and the largest dimension of the x dimension and the y dimension is at least four times the size of the z dimension. Example 23. An aerosol-generating article according to any one of Examples 1 to 22, wherein both the x and y dimensions are at least four times larger than the z dimension. Example 24. An aerosol-generating article according to any one of Examples 1 to 23, wherein the aerosol-forming substrate is in the form of a cylinder defined by a base and a height, for example a right cylinder defined by a base and a height, or the aerosol-forming substrate is in the form of a cube defined by a base and a height. Example 25. An aerosol-generating article according to any one of Examples 1 to 24, wherein the base is defined by a two-dimensional shape that forms the lower surface of the aerosol-forming substrate, and the upper surface of the aerosol-forming substrate is defined by a substantially identical two-dimensional shape that is spaced apart from the base by a height, for example, both the lower and upper surfaces are defined as planar surfaces that lie on parallel planes spaced apart by the height. Example 26. 26. An aerosol-generating article according to any one of Examples 1 to 25, wherein the base of the aerosol-forming substrate forms a lower surface defined by a first two-dimensional shape having a perimeter, and the aerosol-forming substrate further comprises an upper surface defined by a second two-dimensional shape having a perimeter, and one or more peripheral surfaces extending perpendicularly between the first surface and the second surface, for example one or more peripheral surfaces defined between the perimeter of the first shape and the perimeter of the second shape. Example 27. 27. The aerosol-generating article of Example 26, wherein one or more peripheral surfaces are covered by a protective layer, e.g., a protective layer of the same material as the first layer or the same material as the second layer. Example 28. An aerosol-generating article according to any one of Examples 1 to 27, wherein the entire aerosol-forming substrate is enveloped by a protective layer, for example a layer of the same material as the first layer. Example 29. An aerosol-generating article according to any one of Examples 1 to 28, wherein the aerosol-forming substrate has a substantially circular upper surface. Example 30. An aerosol-generating article according to any one of Examples 1 to 29, wherein the aerosol-forming substrate has a substantially circular lower surface. Example 31. 31. An aerosol-generating article according to any one of Examples 1 to 30, wherein the aerosol-forming substrate is in the form of a cylinder, e.g., a right cylinder, defined by a substantially circular base and a height, e.g., the x and y dimensions being equal to the diameter of the circular base of the cylinder, and the z dimension being equal to the height of the cylinder. Example 32. An aerosol-generating article as described in Example 31, wherein the diameter of the base of the cylinder is at least four times the height of the cylinder. Example 33. An aerosol-generating article as described in Example 31, wherein the radius of the base of the cylinder is at least twice the height of the cylinder. Example 34. An aerosol-generating article according to any one of Examples 1 to 33, wherein the ratio of the largest of the x and y dimensions to the z dimension is from 4:1 to 20:1, for example from 4.2:1 to 10:1, for example from 4.5:1 to 8:1. Example 35. An aerosol-generating article according to any one of Examples 1 to 34, wherein the base is circular or substantially circular and the ratio of the diameter of the base (e.g. defined by the x dimension or the y dimension) to the z dimension is from 4:1 to 20:1, for example from 4.2:1 to 10:1, for example from 4.5:1 to 8:1. Example 36. An aerosol-generating article according to any one of Examples 1 to 35, wherein the base is circular or substantially circular and the ratio of the radius of the base (e.g. defined by half the x dimension or half the y dimension) to the z dimension is from 2:1 to 10:1, for example from 2.1:1 to 5:1, for example from 2.25:1 to 4:1. Example 37. 12. An aerosol-generating article according to any one of Examples 1 to 11, wherein the aerosol-forming substrate has an upper surface and / or a lower surface in the form of a polygonal two-dimensional shape, for example a polygon selected from the list consisting of a triangle, a square, a rectangle, a pentagon, a hexagon, a heptagon, an octagon, a nonagon, and a decagon. Example 38. An aerosol-generating article according to any one of Examples 1 to 37, wherein the x dimension and / or the y dimension is from 10 mm to 50 mm, for example from 12 mm to 30 mm, for example from 14 mm to 26 mm, for example from 16 mm to 24 mm, for example from 18 mm to 22 mm, for example about 18 mm, or about 19 mm, or about 20 mm, or about 21 mm, or about 22 mm. Example 39. 39. An aerosol-generating article according to any one of Examples 1 to 38, wherein the aerosol-forming substrate is in the form of a cylinder defined by a circular base and a height, and the diameter of the base is from 10 mm to 50 mm, for example from 12 mm to 30 mm, for example from 14 mm to 26 mm, for example from 16 mm to 24 mm, for example from 18 mm to 22 mm, for example about 18 mm, or about 19 mm, or about 20 mm, or about 21 mm, or about 22 mm. Example 40. 39. An aerosol-generating article according to any one of Examples 1 to 39, wherein the aerosol-forming substrate is in the form of a cylinder defined by a circular base and a height, the radius of the base being from 5 mm to 25 mm, such as from 6 mm to 15 mm, for example from 7 mm to 13 mm, such as from 8 mm to 12 mm, for example from 9 mm to 11 mm, for example about 9 mm, or about 10 mm, or about 11 mm. Example 41. An aerosol-generating article according to any one of Examples 1 to 40, wherein the z dimension is between 1 mm and 5 mm, for example between 1.2 mm and 4.5 mm, for example between 1.4 mm and 4 mm, for example between 1.6 mm and 3.5 mm, for example between 1.7 mm and 3 mm, for example between about 1.7 mm, or about 1.8 mm, or about 1.9 mm, or about 2 mm, or about 2.1 mm. Example 42. 42. An aerosol-generating article according to any one of Examples 1 to 41, wherein the aerosol-forming substrate is in the form of a cylinder defined by a base and a height, the height being between 1 mm and 5 mm, for example between 1.2 mm and 4.5 mm, for example between 1.4 mm and 4 mm, for example between 1.6 mm and 3.5 mm, for example between 1.7 mm and 3 mm, for example between about 1.7 mm, or about 1.8 mm, or about 1.9 mm, or about 2 mm, or about 2.1 mm. Example 43. 27. The aerosol-generating article of Example 26, wherein the aerosol-forming substrate is composed entirely of an aerosol-forming material. Example 44. An aerosol-generating article according to any one of Examples 1 to 43, wherein the aerosol-forming substrate comprises nicotine. Example 45. 45. An aerosol-generating article according to any one of Examples 1 to 44, wherein the aerosol-forming substrate comprises or consists of homogenized tobacco material. Example 46. 46. ​​An aerosol-generating article according to any one of Examples 1 to 45, wherein the aerosol-forming substrate comprises or consists of a solid aerosol-forming material. Example 47. 47. An aerosol-generating article according to any one of Examples 1 to 46, wherein the aerosol-forming substrate comprises, or consists of, a liquid aerosol-forming material held within a porous matrix. Example 48. 48. An aerosol-generating article according to any one of Examples 1 to 47, wherein the aerosol-forming substrate comprises or consists of a gel aerosol-forming material. Example 49. 49. The aerosol-generating article of any one of Examples 1 to 48, wherein a first portion of the aerosol-forming substrate comprises a first aerosol-forming material, and a second portion of the aerosol-forming substrate comprises a second aerosol-forming material different from the first aerosol-forming material. Example 49A. The aerosol-forming material of example 49, wherein the first aerosol-forming material and the second aerosol-forming material extend across the width of the aerosol-forming substrate, for example across the x-direction of the aerosol-forming substrate and / or across the y-direction of the aerosol-forming substrate. Example 49B. The aerosol-forming substrate of Example 49 or 49A, wherein the first aerosol-forming material forms an upper portion of the aerosol-forming substrate and the second aerosol-forming material forms a lower portion of the aerosol-forming substrate. Example 50. 50. The aerosol-generating article of example 49, wherein the first aerosol-forming material and the second aerosol-forming material extend through a thickness of the aerosol-forming substrate, e.g., through the z-direction of the aerosol-forming substrate. Example 51. 51. The aerosol-generating article of Example 50, wherein the first aerosol-forming material occupies a central portion of the base and the second aerosol-forming material occupies a peripheral portion of the base surrounding the central portion. Example 52. An aerosol-generating article as described in Example 50 or 51, wherein the first aerosol-forming material occupies a radially central portion of the base and the second aerosol-forming material occupies a radially peripheral portion of the base surrounding the central portion, for example, the first aerosol-forming material is shaped as a circular cylinder located in the radially central portion of the base and the second aerosol-forming material is shaped as an annular cylinder surrounding the first aerosol-forming material. Example 53. 53. The aerosol-forming article of any one of Examples 49 to 52, wherein the first aerosol-forming material is a first homogenized tobacco material, and the second aerosol-forming material is a second homogenized tobacco material having a different composition than the first homogenized tobacco material. Example 54. 54. The aerosol-forming article of Example 53, wherein the first homogenized tobacco material differs from the second tobacco composition by having at least one difference selected from the list consisting of a different aerosol former content, a different tobacco content, a different flavorant content, a different moisture content, and a different nicotine content. Example 55. An aerosol-generating article according to any one of Examples 1 to 54, wherein a plurality of holes or notches are defined in the upper surface of the aerosol-forming substrate beneath the first layer. Example 56. An aerosol-generating article according to any one of Examples 1 to 55, wherein the base forms the lower surface of the aerosol-forming substrate, the upper surface of the aerosol-forming substrate is substantially parallel to the lower surface and spaced apart from the lower surface by the z dimension, and a plurality of holes or notches are defined in the upper surface of the aerosol-forming substrate below the first layer. Example 57. 57. The aerosol-generating article of any one of Examples 55 and 56, wherein at least some of the plurality of holes are blind holes that do not extend through the thickness of the aerosol-forming substrate. Example 58. 58. The aerosol-generating article of Example 55, 56, or 57, wherein at least some of the plurality of holes are through-holes through the thickness of the aerosol-forming substrate between the top surface and the base. Example 59. An aerosol generating apparatus for heating an aerosol-generating article to generate an aerosol, the aerosol generating apparatus comprising: An aerosol generating device comprising: a cavity for accommodating an aerosol-generating article; and a heater for heating the aerosol-forming article, the heater being arranged to provide heat to a base of the cavity, the base of the cavity being dimensioned to accommodate the base of the aerosol-generating article described in any one of Examples 1 to 58. Example 60. 60. An aerosol generating device as described in Example 59, wherein the heater is a planar heater disposed at or below the base of the depression. Example 61. An aerosol generating device as described in Example 59 or 60, wherein the heater comprises a first portion configured to heat a first portion of the base of the depression and a second portion configured to heat a second portion of the base of the depression. Example 62. An aerosol generating device as described in Example 61, wherein the first portion of the heater is configured to heat a central portion of the base of the depression, and the second portion of the heater is configured to heat a peripheral portion of the base of the depression surrounding the central portion of the base of the depression. Example 63. An aerosol generating device as described in Example 61 or 62, wherein the first portion of the heater is configured to heat a radially central portion of the base of the depression, and the second portion of the heater is configured to heat a radially peripheral portion of the base of the depression surrounding the central portion of the base of the depression, for example, the first portion of the heater heats a radially central circular portion of the base of the depression, and the second portion of the heater heats an annular portion of the base of the depression surrounding the central portion of the base of the depression. Example 64. An aerosol generating device described in any of Examples 61 to 63, wherein the first heater portion and the second heater portion are configured to operate independently of each other to heat respective portions of the base of the depression. Example 65. An aerosol generating device described in any of Examples 61 to 64, wherein the first heater portion and the second heater portion are configured to operate simultaneously to heat respective portions of the base of the depression. Example 66. An aerosol generating device described in any of Examples 61 to 65, wherein the first heater portion and the second heater portion are configured to heat respective portions of the base of the depression to different temperatures. Example 67. 67. The aerosol generating apparatus according to any one of Examples 59 to 66, wherein the heater is a resistance heater. Example 68. 67. The aerosol generating apparatus of any one of Examples 59 to 66, wherein the heater is an induction heater, for example, the heater comprises a susceptor and an inductor.

Claims

1. 1. An aerosol-generating article for use with an aerosol-generating device to form an inhalable aerosol, the aerosol-generating article comprising an aerosol-forming substrate having a base defined by x and y dimensions and a height defined by a z dimension, a planar lower surface of the aerosol-forming substrate defined by the base, and a planar upper surface of the aerosol-forming substrate that is parallel to the planar lower surface, the aerosol-generating article further comprising a first layer configured to protect the planar upper surface and a second layer configured to protect the planar lower surface, at least the first layer being a breathable layer.

2. 2. The aerosol-generating article of claim 1, wherein the first layer and the second layer are formed from the same material.

3. 2. The aerosol-generating article of claim 1, wherein the first layer and the second layer are formed from different materials having different properties, such as different porosities.

4. 4. The aerosol-generating article of claim 3, wherein the second layer is a water-impermeable layer, e.g., a water-impermeable layer configured to prevent water from leaking through the base of the aerosol-generating article when the article is heated.

5. 2. The aerosol-generating article of claim 1, wherein the first layer comprises or consists of a filtering material, such as paper or polymer, having a high density of fine pores configured to allow the passage of gas, such as air, and preferably the first layer comprises a plurality of pores having an average pore size of 10 micrometers to 100 micrometers, and / or the first layer comprises a highly uniform porosity occupying 45% to 70% of the surface of the first layer.

6. The first layer has an air permeability of 75 to 190 cm at a pressure of 200 Pa. 3 / cm 2 / s, for example, 95 to 170 cm at 200 Pa 3 / cm 2 2. The aerosol-generating article according to claim 1, comprising or consisting of a breathable material.

7. 10. The aerosol-generating article of claim 1, wherein the first layer has a thickness of between 35 micrometers and 85 micrometers and / or the first layer is formed from a food-grade filtration layer, such as tea bag material.

8. 10. The aerosol-generating article of claim 1, wherein the second layer is a laminated layer comprising an inner layer and a water-impermeable outer layer.

9. 9. The aerosol-generating article of claim 8, wherein the inner layer is configured to absorb or retain a slurry generated by the aerosol-forming substrate upon heating.

10. 9. An aerosol-generating article according to claim 8, wherein the outer layer is a thermally conductive layer, such as a metal foil layer, such as an aluminum foil layer.

11. 10. The aerosol-generating article of claim 1, wherein at least one of the first layer and the second layer includes printed indicia, such as an identification mark or an orientation mark.

12. 2. The aerosol-generating article of claim 1, wherein at least one of the first layer and the second layer comprises a thermal indicator or a thermochromic indicator configured to indicate whether the aerosol-generating article has been heated above a predetermined temperature.

13. 2. The aerosol-generating article of claim 1, wherein at least one of the first layer and the second layer comprises an embossed layer, for example, an embossed layer that provides a texture of 10 to 50 microns above or below the plane of the layer.

14. 2. The aerosol-generating article of claim 1, wherein the largest of the x and y dimensions is equal to or greater than the z dimension, for example, equal to or greater than twice the z dimension, equal to or greater than three times the z dimension, or equal to or greater than four times the z dimension.

15. An aerosol-generating article according to claim 1 and an aerosol-generating device, the aerosol-generating device comprising: a recess for accommodating the aerosol-generating article; a heater for heating the aerosol-forming article, the heater being arranged to provide heat to a base of the recess, the base of the recess being dimensioned to accommodate the base of the aerosol-generating article.

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