Aerosol-generating article having a susceptor and a thick wrapper

Abstract

The present invention relates to an aerosol-generating article comprising a longitudinal central axis (22) and an aerosol-forming substrate portion (16) containing a susceptor (20) and an aerosol-forming substrate at least partially surrounding the susceptor (20). The substrate wrapper (24) at least partially surrounds the aerosol-forming substrate portion (16) and forms an overlap region of the overlapping end portions of the substrate wrapper (24). The substrate wrapper (24) has a thickness of 50 micrometers or more and includes one or more layers having the same length in a direction parallel to the central axis. The flat, planar susceptor (20) portion is oriented such that the angle between a first line (30) perpendicular to the flat, planar surface (21) of the flat, planar susceptor portion and a second line (32) perpendicular to the central axis (22) and extending from the central axis (22) to a position within the overlap region is between 0 and 25 degrees. The present invention also relates to a package comprising multiple aerosol-generating articles. The present invention further relates to an aerosol-generating system.

Description

[Technical Field]

[0001] The present disclosure relates to an aerosol-generating article. The present disclosure further relates to a package comprising a plurality of aerosol-generating articles. The present disclosure further relates to an aerosol-generating system. [Background technology]

[0002] It is known to provide aerosol-generating devices for producing inhalable vapors. Such devices may heat an aerosol-forming substrate contained in an aerosol-generating article without burning the aerosol-forming substrate. The aerosol-generating article may have a rod shape for insertion into a heating chamber of the aerosol-generating device.

[0003] The aerosol-generating device may include a heating arrangement, which may be an induction heating arrangement and may include an induction coil configured to inductively heat a susceptor, which may be part of the device or part of the aerosol-generating article.

[0004] It would be desirable to provide a more efficient aerosol-generating article. It would be desirable to provide an aerosol-generating article that requires a smaller amount of aerosol-forming substrate. It would be desirable to provide an aerosol-generating article that is mechanically more robust. It would be desirable to provide an aerosol-generating article that can be used with existing aerosol-generating devices. Summary of the Invention

[0005] According to an embodiment of the present invention, there is provided an aerosol-generating article. The aerosol-generating article may have a central axis extending centrally along the longitudinal direction of the aerosol-generating article. The aerosol-generating article may have an aerosol-forming substrate portion. The aerosol-forming substrate portion may contain a susceptor. The aerosol-forming substrate portion may contain an aerosol-forming substrate. The aerosol-forming substrate may at least partially surround the susceptor. The aerosol-generating article may have a substrate wrapper at least partially surrounding the aerosol-forming substrate portion. The substrate wrapper may form an overlap region of overlapping end portions of the substrate wrapper. The substrate wrapper may have a thickness of 50 micrometers or more. The substrate wrapper may include one or more layers having the same length in a direction parallel to the central axis. The susceptor may include a flat, planar susceptor portion. The flat, planar susceptor portion may be oriented such that the angle between a first line perpendicular to the flat, planar surface of the flat, planar susceptor portion and a second line perpendicular to the central axis and extending from the central axis to a position within the overlap region is between 0 degrees and 25 degrees.

[0006] According to one embodiment of the present invention, there is provided an aerosol-generating article having a central axis extending centrally along the longitudinal direction of the aerosol-generating article. The aerosol-generating article comprises an aerosol-forming substrate portion containing a susceptor and an aerosol-forming substrate. The aerosol-forming substrate at least partially surrounds the susceptor. The aerosol-generating article comprises a substrate wrapper at least partially surrounding the aerosol-forming substrate portion. The substrate wrapper forms an overlap region at overlapping end portions of the substrate wrapper. The substrate wrapper has a thickness of 50 micrometers or more. The substrate wrapper includes one or more layers having the same length in a direction parallel to the central axis. The susceptor includes a flat, planar susceptor portion. The flat, planar susceptor portion is oriented such that an angle between a first line perpendicular to the flat, planar surface of the flat, planar susceptor portion and a second line perpendicular to the central axis and extending from the central axis to a position within the overlap region is between 0 and 25 degrees.

[0007] The achieved orientation of the flat, planar susceptor portions allows them to be disposed approximately parallel to the overlap region. This can help to mechanically stabilize the aerosol-generating article during manufacturing when the opposing end portions of the substrate wrapper are pressed together to form the overlapping end portion. This can be particularly helpful in mechanically stabilizing the aerosol-generating article during manufacturing when the opposing end portions of the thick substrate wrapper are pressed together to close the overlapping end portion. The aligned flat portions of the susceptor can function as a stabilizing underlayer when the opposing end portions of the substrate wrapper are pressed together.

[0008] The achieved orientation of the flat, planar susceptor portion relative to the overlap region of the substrate wrapper may allow the flat, planar susceptor portion to be disposed at a greater distance from the overlap region. This may be particularly beneficial when a thick substrate wrapper is used, because, due to its thickness, the thick substrate wrapper can be disposed closer to the central axis compared to a thinner substrate wrapper. This may be particularly beneficial when the overall outer diameter of the aerosol-generating article is kept constant so that the article can be used with existing aerosol-generating devices.

[0009] Glue may be provided in the overlap region to bond the overlapping end portions of the substrate wrapper to one another. During use, the flat, planar susceptor portion is heated. The heated flat, planar susceptor portion being disposed at a greater distance from the overlap region may beneficially reduce or avoid undesired heating of the glue. Thus, the mechanical stability of the aerosol-generating article may be improved. Unintentional generation of malodors by the heated glue may be reduced or avoided.

[0010] A pit, or dead volume, may be formed immediately adjacent to the overlap region. The pits may be disposed substantially circumferentially immediately adjacent to the overlap region. The pits may be formed immediately adjacent to the edge of the inner end portion of the substrate wrapper that is covered by the outer, opposing end portion of the substrate wrapper within the overlap region. The edge of the inner end portion of the substrate wrapper may block the aerosol-forming substrate from entering the pit formed at the edge. The pit may act as a dead volume with no or very little aerosol-forming substrate therein. The pits located at a greater distance from the susceptor mean that they may be located in an area that is less heated by the susceptor. This is due to a thermal gradient around the heated susceptor. Due to the orientation of the flat susceptor portion relative to the overlap region, the pits may therefore be located in an area of the aerosol-forming portion that is not as heated as an area closer to the susceptor. This reduces the amount of heat wasted on heating the dead volume. A more efficient aerosol-generating article may be provided. In particular, a more efficient aerosol-generating article may be provided when a thick substrate wrapper is used, since the thick edges at the inner end portions of the thick substrate wrapper may create larger pits and larger dead volumes.

[0011] The thick wrapper can reduce the diameter of the aerosol-forming portion surrounded by the thick wrapper. The reduced diameter of the aerosol-forming portion can improve thermal contact between the aerosol-forming substrate and the susceptor. A more efficient aerosol-generating article can be provided.

[0012] The combination of all of the one or more layers of the substrate wrapper may define an overall thickness of the substrate wrapper of 50 micrometers or greater. At least one of the one or more layers of the substrate wrapper may have an individual thickness of 50 micrometers or greater. Each of the one or more layers of the substrate wrapper may have an individual thickness of 50 micrometers or greater.

[0013] The substrate wrapper may be arranged so that it does not extend beyond the longitudinal ends of the aerosol-forming substrate portion in a direction parallel to the longitudinal axis of the aerosol-generation portion.

[0014] The substrate wrapper may have a thickness of 60 micrometers or more, preferably 70 micrometers or more, more preferably 75 micrometers or more, more preferably 80 micrometers or more, more preferably 90 micrometers or more, more preferably 100 micrometers or more, more preferably 110 micrometers or more, more preferably 120 micrometers or more, more preferably 130 micrometers or more, more preferably 140 micrometers or more, more preferably 145 micrometers or more, more preferably 150 micrometers or more. The substrate wrapper may have a thickness of about 148 micrometers. The substrate wrapper may have a thickness of 143 micrometers to 153 micrometers. The substrate wrapper may have a thickness of 140 micrometers to 160 micrometers.

[0015] The substrate wrapper may have a uniform thickness that does not vary at any point by more than about 30 micrometers, or more than about 20 micrometers, or more than about 10 micrometers, or more than about 5 micrometers, or more than about 2 micrometers.

[0016] The ratio of the thickness of the substrate wrapper to the diameter of the aerosol-forming substrate portion is in the range of about 1:120 to about 1:20, or about 1:100 to about 1:30, or about 1:80 to about 1:35, or about 1:60 to about 1:40.

[0017] The angle between the first straight line and the second straight line may be 0 to 20 degrees, preferably 0 to 15 degrees, more preferably 0 to 10 degrees, and more preferably 0 to 5 degrees.

[0018] The overlap region may extend along less than 20 percent, preferably less than 15 percent, more preferably less than 10 percent, more preferably less than 5 percent of the circumference of the aerosol-forming substrate portion.

[0019] A second line may be defined as extending from the central axis to the center of the overlap region. "Center of the overlap region" refers to the center of the overlap region along the periphery of the aerosol-generating article, perpendicular to the central axis.

[0020] A second straight line may be defined extending from the central axis to a glue region, or glue line, provided within the overlap region.

[0021] The thickness of the substrate wrapper can be measured in an area that is not an overlap area.

[0022] The susceptor may be a flat, planar susceptor strip. The flat, planar susceptor strip may be elongated in a direction parallel to the central axis. The susceptor may have a length of 5 to 15 millimeters, preferably 9 to 13 millimeters, and a width of at least about 1 millimeter, preferably at least about 2 millimeters.

[0023] The susceptor may be centrally disposed within the aerosol-forming substrate portion.

[0024] The length of the overlap region may be equal to or greater than the length of the susceptor in a direction parallel to the central axis, and the width of the overlap region may be equal to or less than the width of the susceptor in a direction perpendicular to the central axis and parallel to the flat, planar surface of the flat, planar susceptor portion.

[0025] The susceptor may comprise a metallic material, preferably aluminum.

[0026] The substrate wrapper may have a density of 800 kilograms per cubic meter or less. The density of the substrate wrapper may be 750 kilograms per cubic meter or less, preferably 700 kilograms per cubic meter or less, more preferably 650 kilograms per cubic meter or less, more preferably 600 kilograms per cubic meter or less, more preferably 550 kilograms per cubic meter or less, more preferably 500 kilograms per cubic meter or less, more preferably 450 kilograms per cubic meter or less. The density of the substrate wrapper may be 400 kilograms per cubic meter or less, preferably 350 kilograms per cubic meter or less, more preferably about 320 kilograms per cubic meter.

[0027] The density of the substrate wrapper may be 400 kilograms per cubic meter or less, and the substrate wrapper may have a thickness of 60 micrometers or more, preferably 70 micrometers or more, more preferably 75 micrometers or more, more preferably 80 micrometers or more, more preferably 90 micrometers or more, more preferably 100 micrometers or more, more preferably 110 micrometers or more, more preferably 120 micrometers or more, more preferably 130 micrometers or more, more preferably 140 micrometers or more, more preferably 145 micrometers or more, and more preferably 150 micrometers or more. The substrate wrapper may have a thickness of about 148 micrometers. The density of the substrate wrapper may be 400 kilograms per cubic meter or less, and the substrate wrapper may have a thickness of 143 micrometers to 153 micrometers. The density of the substrate wrapper may be 400 kilograms per cubic meter or less, and the substrate wrapper may have a thickness of 140 micrometers to 160 micrometers.

[0028] The substrate wrapper may have a basis weight of less than 60 grams per square meter. The substrate wrapper may have a basis weight of greater than 28 grams per square meter and less than 60 grams per square meter. The substrate wrapper may have a basis weight of greater than 45 grams per square meter and less than 60 grams per square meter.

[0029] The basis weight of the substrate wrapper may be less than 50 grams per square meter. The basis weight of the substrate wrapper may be greater than 28 grams per square meter and less than 50 grams per square meter. The basis weight of the substrate wrapper may be greater than 45 grams per square meter and less than 50 grams per square meter. The basis weight of the substrate wrapper may be about 48 grams per square meter.

[0030] The substrate wrapper may have a thickness greater than 145 micrometers and a density of 400 kilograms per cubic meter or less.

[0031] The substrate wrapper may contain one or more perforations, or may contain no perforations at all.

[0032] The substrate wrapper may exhibit a wrapper permeability of greater than 10 Coresta units, greater than 20 Coresta units, greater than 50 Coresta units, greater than 100 Coresta units, greater than 500 Coresta units, greater than 1000 Coresta units, greater than 1500 Coresta units, greater than 2000 Coresta units, greater than 2500 Coresta units, greater than 3000 Coresta units, greater than 3500 Coresta units, or greater than 4000 Coresta units. The substrate wrapper may exhibit a wrapper permeability of 10 Coresta units to 10,000 Coresta units, preferably 50 Coresta units to 8000 Coresta units, and more preferably 100 Coresta units to 5000 Coresta units. The substrate wrapper may exhibit a wrapper permeability of 4000 Coresta units to 4800 Coresta units, preferably 4200 Coresta units to 4600 Coresta units, and more preferably 4300 Coresta units to 4500 Coresta units.

[0033] The substrate wrapper can have a thickness greater than 145 micrometers, a density of 400 kilograms per cubic meter or less, and a wrapper permeability of 50 Coresta units to 5000 Coresta units, preferably 4200 Coresta units to 4600 Coresta units, and more preferably 4300 Coresta units to 4500 Coresta units.

[0034] The permeability of the substrate wrapper can be determined using the international standard test method ISO 2965:2009, and the results can be presented as cubic centimeters per minute per square centimeter, and can be referred to as "Cholesta units."

[0035] The aerosol-generating article may include an additional wrapper surrounding the base wrapper. The additional wrapper may exhibit a wrapper permeability of less than 100 Coresta units, less than 80 Coresta units, less than 50 Coresta units, less than 40 Coresta units, or less than 30 Coresta units. The permeability of the additional wrapper may be less than that of the base wrapper. The permeability of the additional wrapper may be less than 1%, less than 2%, less than 5%, less than 10%, or less than 20% of the permeability of the base wrapper. The permeability of the additional wrapper may be less than 50 Coresta units, and the permeability of the base wrapper may be 4000 Coresta units to 4800 Coresta units, preferably 4200 Coresta units to 4600 Coresta units, and more preferably 4300 Coresta units to 4500 Coresta units. The additional wrapper may be a tipping wrapper as described herein. The additional wrapper may be a combination wrapper. The additional wrapper can advantageously reduce the overall permeability where a substrate wrapper with high permeability is used.

[0036] The substrate wrapper may or may not be embossed. The substrate wrapper may be both perforated and embossed.

[0037] The term "embossment" is used herein to refer to protrusions formed on the surface of a wrapper. These protrusions may be engraved, molded, or stamped into the wrapper. A portion of a wrapper with such embossment is said to be embossed.

[0038] The substrate wrapper may include an embossed portion. The embossed portion of the substrate wrapper may have a single embossment. The embossed portion of the substrate wrapper may have multiple embossments. The one or more embossments may have a depth of 0.07 mm to 0.21 mm, preferably 0.10 mm to 0.18 mm, and more preferably 0.12 mm to 0.16 mm. Each embossment may also have a pitch of 0.2 mm to 0.4 mm, preferably 0.25 mm to 0.35 mm, and more preferably 0.275 mm to 0.325 mm.

[0039] The substrate wrapper may have a roughness of from about 50 Bekk seconds to about 1000 Bekk seconds, preferably from about 100 Bekk seconds to about 200 Bekk seconds. Roughness, expressed in Bekk seconds, can be measured by a standard test using a BEKK Smoothness Tester, which generates a vacuum and measures the time it takes for the vacuum to drop from 50.66 kPa to 48.00 kPa. This test is recognized by international standard ISO 5627.

[0040] As used herein, the "total density of the aerosol-forming substrate portion" refers to the total mass of material contained within the volume enclosed by the substrate wrapper divided by the volume enclosed by the substrate wrapper. The mass of the substrate wrapper itself and any optional additional wrappers surrounding the substrate wrapper are not taken into account. The volume of the substrate wrapper itself and any optional additional wrappers surrounding the substrate wrapper are not taken into account.

[0041] The total density of the aerosol-forming substrate portion can be determined after conditioning the aerosol-generating article according to ISO standard 3402:1999. The aerosol-forming substrate is removed from the aerosol-forming substrate portion and weighed. The susceptor is also removed from the aerosol-forming substrate portion and weighed. The internal volume of the aerosol-forming substrate portion is determined. This can be done, for example, by laser measurement. The internal volume of the aerosol-forming substrate portion generally corresponds to the cylindrical volume within the substrate wrapper. The total density of the aerosol-forming substrate portion is calculated by dividing the sum of the mass of the aerosol-forming substrate and the mass of the susceptor by the internal volume of the substrate portion. This can be repeated 20 times for 20 different individual aerosol-generating articles to obtain an average value.

[0042] As used herein, the "total density of the aerosol-generating article at a longitudinal position of the aerosol-forming substrate portion" refers to the total mass of material contained within a volume defined by the average cross-sectional area of the aerosol-generating article along the length of the aerosol-forming substrate portion, divided by said volume. The masses of the aerosol-forming substrate, susceptor, substrate wrapper, and one or more optional additional wrappers surrounding the substrate wrapper are taken into account. The volume of the substrate wrapper itself and one or more optional additional wrappers surrounding the substrate wrapper are taken into account.

[0043] The "total density of the aerosol-generating article at a position along the longitudinal axis of the aerosol-forming substrate portion" may be determined after conditioning the aerosol-generating article in accordance with ISO standard 3402:1999.

[0044] The thickness of the substrate wrapper may be determined in accordance with ISO 534:2011. The density of the substrate wrapper may be determined in accordance with ISO 534:2011. The thickness of the substrate wrapper may be determined in accordance with ASTM E252-06(2021)e1. Generally, for an embossed substrate wrapper, the local thickness at the embossed location may be less than the thickness at a non-embossed location. As used herein, for an embossed wrapper, the thickness of the substrate wrapper refers to the thickness at a non-embossed location. For an embossed wrapper, the thickness of the substrate wrapper may be determined before the wrapper is embossed.

[0045] Unless otherwise defined, all measurements described herein are performed after sample conditioning according to ISO standard 3402:1999.

[0046] The density of the substrate wrapper can be calculated by dividing the basis weight of the substrate wrapper by the thickness of the substrate wrapper. Basis weight, also called grammage, refers to the mass of the substrate wrapper per sheet size and is usually expressed in grams per square meter. Basis weight can be obtained, for example, by weighing a one square meter sheet of the substrate wrapper.

[0047] As used herein, the term "lightweight" when referring to the substrate wrapper means that the density of the substrate wrapper is 800 kilograms per cubic meter or less, preferably 750 kilograms per cubic meter or less, more preferably 700 kilograms per cubic meter or less, more preferably 650 kilograms per cubic meter or less, more preferably 600 kilograms per cubic meter or less, more preferably 550 kilograms per cubic meter or less, more preferably 500 kilograms per cubic meter or less, more preferably 450 kilograms per cubic meter or less, more preferably 400 kilograms per cubic meter or less, more preferably 350 kilograms per cubic meter or less, and more preferably about 320 kilograms per cubic meter.

[0048] As used herein, the term "thick" when referring to a substrate wrapper means that the thickness of the substrate wrapper is 50 micrometers or greater, preferably 60 micrometers or greater, more preferably 70 micrometers or greater, more preferably 75 micrometers or greater, more preferably 80 micrometers or greater, more preferably 90 micrometers or greater, more preferably 100 micrometers or greater, more preferably 110 micrometers or greater, more preferably 120 micrometers or greater, more preferably 130 micrometers or greater, more preferably 140 micrometers or greater, more preferably 145 micrometers or greater, more preferably 150 micrometers or greater.

[0049] The substrate wrapper may extend along the entire length of the aerosol-forming substrate portion in a direction along the longitudinal axis of the aerosol-generating article. The substrate wrapper may extend along at least 40 percent, preferably at least 50 percent, more preferably at least 60 percent, more preferably at least 70 percent, more preferably at least 80 percent, more preferably at least 90 percent, and more preferably at least 95 percent of the length of the aerosol-forming substrate portion in a direction along the longitudinal axis of the aerosol-generating article.

[0050] The substrate wrapper may be in direct physical contact with the aerosol-forming substrate, in which case there is no layer of material between the substrate wrapper and the aerosol-forming substrate.

[0051] The substrate wrapper may be formed from a single continuous sheet of material. The single continuous sheet may be wrapped around the aerosol-forming substrate portion in approximately one wrap. Generally, the single continuous sheet may be wrapped around the substrate portion in as few as two or more wraps to form an overlap region of the opposing end portions of the substrate wrapper. The thickness of the wrapper is not measured at the overlap region. Thus, a substrate wrapper formed from a single continuous sheet of material may include only a single layer, excluding the optional overlap region, if present.

[0052] The substrate wrapper may be formed from a single continuous sheet wrapped around the aerosol-forming substrate portion in at least about two or more turns. In this case, two or more layers of substrate wrapper are wrapped around the aerosol-forming substrate portion without taking into account the additional overlap region formed by the overlapping opposing end portions of the wrapper. In this case, the thickness of the substrate wrapper may be obtained by multiplying the thickness of each individual layer, i.e., the thickness of the sheet, by the number of turns. The thickness of the substrate wrapper is not obtained by multiplying the thickness of each individual layer by the number of turns of the overlap region formed by the overlapping opposing end portions of the wrapper. None of the individual layers extend beyond the ends of the aerosol-forming substrate portion in the longitudinal direction of the aerosol-generating article.

[0053] The substrate wrapper may include one or more of cardboard, plastic, and metal foil.

[0054] The substrate wrapper may comprise one or more cellulosic materials, such as paper, wood, textiles, natural fibers, and artificial fibers. The substrate wrapper may comprise a paper layer. The substrate wrapper may be made of a single paper sheet. The substrate wrapper may comprise a single paper layer wrapped around the aerosol-forming substrate portion, excluding optional overlapping portions. The substrate wrapper may be made of a single paper sheet wrapped around the aerosol-forming substrate portion two or more times, resulting in a substrate wrapper comprising two or more layers having the same length.

[0055] The substrate wrapper may be a paper wrapper or a non-paper wrapper. Suitable non-paper wrappers include, but are not limited to, sheets of homogenized tobacco material.

[0056] The substrate wrapper may comprise a laminate sheet. The substrate wrapper may be made of a single laminate sheet. The laminate sheet may be a laminate of a paper layer and an aluminum layer.

[0057] The wrapper may be formed from a laminate material including multiple layers. The wrapper may be formed from a metal co-laminate sheet, for example, an aluminum co-laminate sheet. The metal layer of the co-laminate sheet may have a basis weight of 12 grams per square meter to 25 grams per square meter, preferably 15 grams per square meter to 20 grams per square meter. The metal layer of the co-laminate sheet may have a thickness of 2 micrometers to 15 micrometers, preferably 3 micrometers to 12 micrometers, and more preferably 5 micrometers to 10 micrometers.

[0058] The substrate wrapper may be a paper wrapper containing PVOH (polyvinyl alcohol) or silicon (or polysiloxane). The addition of PVOH (polyvinyl alcohol) or silicon (or polysiloxane) may improve the grease barrier properties of the wrapper.

[0059] The substrate wrapper may include a flame retardant composition comprising one or more flame retardant compounds. The term "flame retardant compound" is used herein to describe a compound that, when added to or otherwise incorporated into a carrier substrate, such as a paper or plastic compound, provides varying degrees of flammability protection to the carrier substrate.

[0060] Many suitable flame retardant compounds are known to those skilled in the art. In particular, several flame retardant compounds and formulations suitable for treating cellulosic materials are known and disclosed and may find use in the manufacture of wrappers for aerosol-generating articles according to the present invention.

[0061] The substrate wrapper may be a substrate wrapper system formed from two or more individual substrate wrapper sub-sheets. In that case, the thickness of the substrate wrapper may be obtained by adding the thicknesses of the individual substrate wrapper sub-sheets of the substrate wrapper system. None of the individual substrate wrapper sub-sheets may extend beyond the ends of the aerosol-forming substrate portion in the longitudinal direction of the aerosol-generating article. Each of the individual substrate wrapper sub-sheets forming the substrate wrapper system may be the same length in a direction parallel to the longitudinal axis of the aerosol-generating article.

[0062] The substrate wrapper may be a substrate wrapper system formed from two or more individual substrate wrapper sub-sheets, each of which at least partially surrounds the aerosol-forming substrate portion, and none of the two or more individual substrate wrapper sub-sheets extends beyond the edge of the aerosol-forming substrate portion in the longitudinal direction of the aerosol-generating article, and each of the two or more individual substrate wrapper sub-sheets has a thickness of 50 micrometers or more and a density of 800 kilograms per cubic meter or less, and preferably each of the individual substrate wrapper sub-sheets forming the substrate wrapper system are the same length in a direction parallel to the longitudinal axis of the aerosol-generating article.

[0063] The substrate wrapper may be a substrate wrapper system formed from two or more individual substrate wrapper sub-sheets, each of which at least partially surrounds an aerosol-forming substrate portion, each of which has the same length in the longitudinal direction of the aerosol-generating article, and each of which has a thickness of 50 micrometers or more and a density of 800 kilograms per cubic meter or less.

[0064] The substrate wrapper may be a substrate wrapper system formed from two or more individual substrate wrapper sub-sheets, each of which at least partially surrounds the aerosol-forming substrate portion, and none of the two or more individual substrate wrapper sub-sheets extends beyond the edge of the aerosol-forming substrate portion in the longitudinal direction of the aerosol-generating article, and the two or more individual substrate wrapper sub-sheets together have a thickness of 50 micrometers or more and a density of 800 kilograms per cubic meter or less, and preferably each of the individual substrate wrapper sub-sheets forming the substrate wrapper system are the same length in a direction parallel to the longitudinal axis of the aerosol-generating article.

[0065] The substrate wrapper may be a substrate wrapper system formed from two or more individual substrate wrapper sub-sheets, each of which at least partially surrounds an aerosol-forming substrate portion, each of which has the same length in the longitudinal direction of the aerosol-generating article, and the two or more individual substrate wrapper sub-sheets together have a thickness of 50 micrometers or more and a density of 800 kilograms per cubic meter or less.

[0066] The substrate-wrapper system may be formed from two individual sheets. The substrate-wrapper system may be formed from a first individual sheet and a second individual sheet. The first individual sheet may be provided by a first wrapper including a first overlap region formed by overlapping opposing end portions of the first wrapper. The second individual sheet may be provided by a second wrapper including a second overlap region formed by overlapping opposing end portions of the second wrapper. The first overlap region may be offset from the second overlap region by at least about 5 percent of the circumference of the aerosol-forming substrate portion, preferably at least about 10 percent of the circumference of the aerosol-forming substrate portion, more preferably at least about 15 percent of the circumference of the aerosol-forming substrate portion, and more preferably about 40 percent to about 60 percent of the circumference of the aerosol-forming substrate portion. The first overlap region may be offset from the second overlap region by about 50 percent of the circumference of the aerosol-forming substrate portion. The first and second overlap regions are provided on opposite sides of a flat, planar susceptor portion. One or both of the first and second individual sheets may be paper wrappers.

[0067] The aerosol-generating article may comprise a downstream section located downstream of the aerosol-forming substrate portion. The downstream section is preferably located immediately downstream of the aerosol-forming substrate portion. The downstream section of the aerosol-generating article preferably extends between the aerosol-forming substrate portion and the downstream end of the aerosol-generating article. The downstream section may comprise one or more elements, each of which is described in more detail within this disclosure.

[0068] The length of the downstream section may be at least 10 millimeters, or at least 20 millimeters, or at least 25 millimeters, or at least 30 millimeters.

[0069] The length of the downstream section may be less than 70 millimeters, or less than 60 millimeters, or less than 50 millimeters.

[0070] For example, the length of the downstream section can be between 20 millimeters and 70 millimeters, or between 25 millimeters and 60 millimeters, or between 30 millimeters and 50 millimeters.

[0071] The downstream section of the aerosol-generating article according to the present invention preferably comprises a hollow tubular cooling element provided downstream of the aerosol-forming substrate portion, which may advantageously provide the aerosol cooling element for the aerosol-generating article.

[0072] The hollow tubular cooling element may be provided immediately downstream of the aerosol-forming substrate portion. In other words, the hollow tubular cooling element may abut the downstream end of the aerosol-forming substrate portion. The hollow tubular cooling element may define the upstream end of the downstream section of the aerosol-generating article. The downstream end of the aerosol-generating article may coincide with the downstream end of the downstream section. In some embodiments, the downstream section of the aerosol-generating article comprises a single hollow tubular element. In other words, the downstream section of the aerosol-generating article may comprise only one hollow tubular element. In other embodiments, the downstream section comprises two or more hollow tubular elements, as described below.

[0073] As used throughout this disclosure, the term "hollow tubular element" generally refers to an elongated element that defines a lumen or airflow passage along its longitudinal axis. In particular, the term "tubular" is used hereinafter with reference to a tubular element that has a substantially cylindrical cross-section and defines at least one airflow conduit that establishes uninterrupted fluid communication between the upstream end of the tubular element and the downstream end of the tubular element. However, it will be appreciated that alternative shapes of the tubular element (e.g., alternative cross-sectional shapes) may be possible. A hollow tubular cooling element may be an individual, separate element of an aerosol-generating article, having a defined length and thickness.

[0074] In the context of the present invention, a hollow tubular cooling element provides an unrestricted flow channel, which means that the hollow tubular cooling element provides a negligible resistance to withdrawal (RTD). The term "negligible RTD" is used to indicate an RTD of less than 1 millimeter of water column per 10 millimeters of hollow tubular cooling element length, preferably less than 0.4 millimeters of water column per 10 millimeters of hollow tubular cooling element length, and more preferably less than 0.1 millimeters of water column per 10 millimeters of hollow tubular cooling element length.

[0075] Preferably, the RTD of the hollow tubular cooling element is 10 mm water column or less, or 5 mm water column or less, or 2.5 mm water column or less, or 2 mm water column or less, or 1 mm water column or less.

[0076] The RTD of the hollow tubular cooling element can be at least 0 millimeters of water column, or at least 0.25 millimeters of water column, or at least 0.5 millimeters of water column, or at least 1 millimeter of water column.

[0077] In an aerosol-generating article according to the present invention, the overall RTD of the article depends essentially on the RTD of the rod and, optionally, the RTD of downstream and / or upstream elements, since the hollow tubular cooling element is substantially empty and therefore makes only a substantially small contribution to the overall RTD of the aerosol-generating article.

[0078] Therefore, the flow channels should not include any components that would impede the longitudinal air flow. It is preferred that the flow channels are substantially empty, and it is particularly preferred that the flow channels are empty.

[0079] As described in more detail herein, the aerosol-generating article may include ventilation zones at locations along the downstream section. In some embodiments, the aerosol-generating article may include ventilation zones at locations along the hollow tubular cooling element. These or any ventilation zones may extend through the peripheral wall of the hollow tubular cooling element. In this manner, fluid communication is established between the flow channels internally defined by the hollow tubular cooling element and the external environment. Ventilation zones are described further herein.

[0080] The length of the hollow tubular cooling element can be at least 15 millimeters, or at least 20 millimeters, or at least 25 millimeters. The length of the hollow tubular cooling element can be less than 50 millimeters, or less than 45 millimeters, or less than 40 millimeters. For example, the length of the hollow tubular cooling element can be 15 millimeters to 50 millimeters, or 20 millimeters to 45 millimeters, or 20 millimeters to 40 millimeters, or 20 millimeters to 30 millimeters, or 25 millimeters to 40 millimeters.

[0081] The relatively long, hollow, tubular cooling element provides and defines a relatively long internal cavity within the aerosol-generating article and downstream of the aerosol-forming substrate portion. Providing an empty cavity downstream (preferably immediately downstream) of the aerosol-forming substrate enhances nucleation of aerosol particles generated by the substrate. Providing a relatively long cavity maximizes the benefits of such nucleation, thereby improving aerosol formation and cooling.

[0082] The wall thickness of the hollow tubular cooling element may be between 100 micrometers and 2 millimeters, or between 150 micrometers and 1.5 millimeters, or between 200 micrometers and 1.25 millimeters.

[0083] The hollow tubular cooling element preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article.

[0084] The hollow tubular cooling element can have an outer diameter of 5 millimeters to 10 millimeters, e.g., 5.5 millimeters to 9 millimeters, or 6 millimeters to 8 millimeters. In certain embodiments, the hollow tubular cooling element has an outer diameter of less than 7 millimeters.

[0085] The hollow tubular cooling element may have an inner diameter. Preferably, the hollow tubular cooling element has a constant inner diameter along the length of the hollow tubular cooling element. However, the inner diameter of the hollow tubular cooling element may vary along the length of the hollow tubular cooling element.

[0086] The hollow tubular cooling element may have an inner diameter of at least 2 millimeters. For example, the hollow tubular cooling element may have an inner diameter of at least 3 millimeters, at least 4 millimeters, or at least 5 millimeters.

[0087] Providing a hollow tubular cooling element with an inner diameter as set out above may advantageously provide the hollow tubular cooling element with sufficient stiffness and strength.

[0088] The hollow tubular cooling element may have an inner diameter of 10 millimeters or less. For example, the hollow tubular cooling element may have an inner diameter of 9 millimeters or less, 8 millimeters or less, or 7 millimeters or less.

[0089] Providing a hollow tubular cooling element with an inner diameter as set out above may advantageously reduce the resistance to drawing the hollow tubular cooling element.

[0090] The hollow tubular cooling element may have an inner diameter of 2 millimeters to 10 millimeters, 3 millimeters to 9 millimeters, 4 millimeters to 8 millimeters, or 5 millimeters to 7 millimeters.

[0091] The lumen or cavity of the hollow tubular cooling element may have any cross-sectional shape. The lumen of the hollow tubular cooling element may have a circular cross-sectional shape.

[0092] The hollow tubular cooling element may comprise a paper-based material. The hollow tubular cooling element may comprise at least one layer of paper. The paper may be a very stiff paper. The paper may be a crimped paper, such as crimped heat-resistant paper or crimped parchment paper.

[0093] Preferably, the hollow tubular cooling element may comprise cardboard. The hollow tubular cooling element may be a cardboard tube. The hollow tubular cooling element may be formed from cardboard. Advantageously, cardboard is a cost-effective material that provides a balance between being deformable to provide ease of insertion of an item into the aerosol generating device and being sufficiently rigid to provide proper engagement of the item with the interior of the device. Thus, a cardboard tube may provide adequate resistance to deformation or compression during use.

[0094] The hollow tubular cooling element can be a paper tube. The hollow tubular cooling element can be a tube formed from spirally wound paper. The hollow tubular cooling element can be formed from multiple layers of paper. The paper can have a basis weight of at least 50 grams per square meter, at least 60 grams per square meter, at least 70 grams per square meter, or at least 90 grams per square meter.

[0095] The hollow tubular cooling element may comprise a polymeric material. For example, the hollow tubular cooling element may comprise a polymeric film. The polymeric film may comprise a cellulose film. The hollow tubular cooling element may comprise low-density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers. The hollow tube may comprise cellulose acetate tow.

[0096] When the hollow tubular cooling element comprises cellulose acetate tow, the cellulose acetate tow may have a denier per filament of 2 to 4 and a total denier of 25 to 40.

[0097] Preferably, aerosol-generating articles according to the present invention comprise a ventilation zone located along the downstream section. More particularly, in those embodiments in which the downstream section comprises a hollow tubular cooling element, a ventilation zone may be provided along the hollow tubular cooling element. Alternatively or additionally, in those embodiments in which the downstream section comprises a downstream hollow tubular element, a ventilation zone may be provided along the downstream hollow tubular element.

[0098] Thus, a vented cavity is provided downstream of the aerosol-forming substrate portion, which offers several potential technical advantages. First, the inventors have found that one such vented hollow tubular cooling element provides particularly efficient cooling of the aerosol. Second, the inventors have surprisingly found that such rapid cooling of volatile species released upon heating of the aerosol-forming substrate enhances nucleation of aerosol particles.

[0099] A ventilation zone typically includes a plurality of perforations through the circumferential wall of the hollow tubular cooling element. Preferably, the ventilation zone includes at least one circumferential row of perforations. In some embodiments, the ventilation zone may include two circumferential rows of perforations. For example, the perforations may be formed online during the manufacture of the aerosol-generating article. Preferably, each circumferential row of perforations includes between 8 and 30 perforations.

[0100] Aerosol-generating articles according to the present invention may have a ventilation level of at least 40 percent. Increasing the ventilation level may increase the level of aerosol cooling. However, increasing the ventilation level may mean that less air enters the aerosol-generating article through the upstream end of the aerosol-generating article and then flows through the aerosol-forming substrate portion. The ventilation level may thereby be selected based on the desired temperature and composition of the aerosol delivered to the user.

[0101] The aerosol-generating article preferably has a breathability level of at least 45 percent, more preferably at least 50 percent, more preferably at least 60 percent, more preferably at least 70 percent.

[0102] Aerosol-generating articles according to the present invention may have breathability levels of 90 percent or less, more preferably 85 percent or less, more preferably 80 percent or less.

[0103] Therefore, aerosol-generating articles according to the present invention may have a breathability level of 45 to 90 percent, more preferably 45 to 85 percent, and even more preferably 45 to 80 percent. Aerosol-generating articles according to the present invention may have a breathability level of 50 to 90 percent, preferably 50 to 85 percent, and more preferably 50 to 80 percent. Aerosol-generating articles according to the present invention may have a breathability level of 60 to 90 percent, preferably 60 to 85 percent, and more preferably 60 to 80 percent. Aerosol-generating articles according to the present invention may have a breathability level of 70 to 90 percent, preferably 70 to 85 percent, and more preferably 70 to 80 percent.

[0104] For example, the aerosol-generating article may have a breathability level of about 75 percent.

[0105] As discussed in this disclosure, the downstream section may include a downstream filter segment. The downstream filter segment may extend to the downstream end of the downstream section. The downstream filter segment may be located at the downstream end of the aerosol-generating article. The downstream end of the downstream filter segment may define the downstream end of the aerosol-generating article. The downstream filter segment may also be referred to as a mouth end filter.

[0106] The downstream filter segment may be located downstream of the hollow tubular cooling element, as described above, and may extend between the hollow tubular cooling element and the downstream end of the aerosol-generating article.

[0107] The downstream filter segment is preferably a solid plug, which may also be described as a "plain" plug, and is non-tubular. Thus, the filter segment preferably has a substantially uniform cross-section.

[0108] The downstream filter segment is preferably formed of a fibrous filter material. The fibrous filter material may be for filtering the aerosol generated from the aerosol-forming substrate. Suitable fibrous filter materials will be known to those skilled in the art. Particularly preferably, at least one downstream filter segment comprises a cellulose acetate filter segment formed from cellulose acetate tow.

[0109] In certain preferred embodiments, the downstream section comprises a single downstream filter segment. In alternative embodiments, the downstream section comprises two or more downstream filter segments axially aligned in end-to-end abutting relationship with one another.

[0110] The downstream filter segment may optionally include a flavorant, which may be provided in any suitable form, for example, the downstream filter segment may comprise one or more capsules, beads, or granules of flavorant, or one or more flavor-loaded threads or filaments.

[0111] The downstream filter segment preferably has a low particle filtration efficiency.

[0112] The downstream filter segment is preferably surrounded by plug wrap. The downstream filter segment is preferably non-vented so that air does not enter the aerosol-generating article along the downstream filter segment.

[0113] The downstream filter segment is preferably connected to one or more of the adjacent upstream components of the aerosol-generating article by a tipping wrapper.

[0114] The downstream filter segment preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article. The outer diameter of the downstream filter segment may be substantially the same as the outer diameter of the hollow tubular cooling element.

[0115] The outer diameter of the downstream filter segment can be between 5 and 10 millimeters, or between 5.5 and 9 millimeters, or between 6 and 8 millimeters. In certain embodiments, the outer diameter of the downstream filter segment is less than 7 millimeters.

[0116] Unless otherwise specified, the resistance to draw (RTD) of a component or aerosol-generating article is measured in accordance with ISO 6565-2015. RTD refers to the pressure required to force air through the entire length of the component. The terms "pressure drop" or "draw resistance" of a component or article may also refer to "resistance to draw." Such terms generally refer to measurements in accordance with ISO 6565-2015 normally performed at a temperature of 22 degrees Celsius, a pressure of 101 kPa (approximately 760 Torr), and 60% relative humidity, with a volumetric flow rate of 17.5 milliliters per second at the output or downstream end of the measured component. Smoking conditions and smoking machine specifications are provided in ISO Standard 3308 (ISO 3308:2000). Conditioning and testing atmospheres are provided in ISO Standard 3402 (ISO 3402:1999).

[0117] Resistance to withdrawal (RTD) can be expressed in pressure units "millimeters of water column" (mmWG).

[0118] The resistance to drawing (RTD) of the downstream section may be at least 0 millimeters of water column. The RTD of the downstream section may be at least 3 millimeters of water column. The RTD of the downstream section may be at least 6 millimeters of water column. The RTD of the downstream section may be no greater than 12 millimeters of water column. The RTD of the downstream section may be no greater than 11 millimeters of water column. The RTD of the downstream section may be no greater than 10 millimeters of water column.

[0119] The resistance to draw (RTD) characteristics of the downstream section may be entirely or predominantly attributable to the RTD characteristics of the downstream filter segments of the downstream section. In other words, the RTD of the downstream filter segments of the downstream section may completely define the RTD of the downstream section.

[0120] The resistance to draw (RTD) of the downstream filter segment may be at least 0 millimeters of water column, or at least 3 millimeters of water column, or at least 6 millimeters of water column. The RTD of the downstream filter segment may be no more than 12 millimeters of water column, or no more than 11 millimeters of water column, or no more than 10 millimeters of water column.

[0121] As described above, the downstream filter segment may be formed from a fibrous material. The downstream filter segment may be formed from a porous material. The downstream filter segment may be formed from a biodegradable material. The downstream filter segment may be formed from a cellulose material, such as cellulose acetate. For example, the downstream filter segment may be formed from a bundle of cellulose acetate fibers having 10-15 denier per filament. For example, the downstream filter segment may be formed from a relatively low density cellulose acetate tow, such as a cellulose acetate tow containing 12 denier fibers per filament.

[0122] The downstream filter segment may be formed of a polylactic acid-based material. The downstream filter segment may be formed of a bioplastic material, preferably a starch-based bioplastic material. The downstream filter segment may be fabricated by injection molding or extrusion. Bioplastic-based materials are advantageous because they can provide a downstream filter segment structure that is simple and inexpensive to manufacture due to a specific complex cross-sectional profile that may include multiple relatively large airflow channels extending through the downstream filter segment material, providing favorable RTD characteristics.

[0123] The length of the downstream filter segment can be at least 5 millimeters, or at least 10 millimeters. The length of the downstream filter segment can be less than 25 millimeters, or less than 20 millimeters. For example, the length of the downstream filter segment can be 5 millimeters to 25 millimeters, or 10 millimeters to 25 millimeters, or 5 millimeters to 20 millimeters, or 10 millimeters to 20 millimeters.

[0124] The downstream section may further comprise one or more additional hollow tubular elements.

[0125] In certain embodiments, the downstream section may comprise a hollow tubular support element upstream of the hollow tubular cooling element. Preferably, the hollow tubular support element abuts the downstream end of the aerosol-forming substrate portion. Preferably, the hollow tubular support element abuts the upstream end of the hollow tubular cooling element. Preferably, the hollow tubular support element and the hollow tubular cooling element are adjacent to each other and together provide a hollow tubular section within the downstream section.

[0126] The hollow tubular support element may be formed from any suitable material or combination of materials. For example, the support element may be formed from one or more materials selected from the group consisting of cellulose acetate, cardboard, crimped paper (such as crimped heat-resistant paper or crimped parchment paper), and polymeric materials (such as low-density polyethylene (LDPE)). In a preferred embodiment, the support element is formed from cellulose acetate. Other suitable materials include polyhydroxyalkanoate (PHA) fibers. In a preferred embodiment, the hollow tubular support element comprises a hollow acetate tube.

[0127] The hollow tubular support element preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article.

[0128] The hollow tubular support element can have an outer diameter of 5 to 10 millimeters, for example, 5.5 to 9 millimeters, or 6 to 8 millimeters. In a preferred embodiment, the hollow tubular support element has an outer diameter of less than 7 millimeters.

[0129] The hollow tubular support element may have a wall thickness of at least 1 millimeter, preferably at least 1.5 millimeters, and more preferably at least 2 millimeters.

[0130] The hollow tubular support element may have a length of at least 5 millimeters. Preferably, the support element has a length of at least 6 millimeters, more preferably at least 7 millimeters.

[0131] The hollow tubular support element may have a length of less than 15 millimeters. Preferably, the hollow tubular support element has a length of less than 12 millimeters, more preferably less than 10 millimeters.

[0132] In some embodiments, the hollow tubular support element has a length of 5 mm to 15 mm, preferably 6 mm to 15 mm, and more preferably 7 mm to 15 mm. In other embodiments, the hollow tubular support element has a length of 5 mm to 12 mm, preferably 6 mm to 12 mm, and more preferably 7 mm to 12 mm. In further embodiments, the support element has a length of 5 mm to 10 mm, preferably 6 mm to 10 mm, and more preferably 7 mm to 10 mm.

[0133] Alternatively or in addition to the hollow tubular support element, the downstream section may further comprise a downstream hollow tubular element downstream of the hollow tubular cooling element. The downstream hollow tubular element may be provided immediately adjacent to the hollow tubular cooling element. Alternatively and preferably, the downstream hollow tubular element is separated from the hollow tubular cooling element by at least one other component. For example, the downstream section may comprise a downstream filter segment between the hollow tubular cooling element and the downstream hollow tubular element.

[0134] The downstream hollow tubular element preferably extends to the downstream end of the downstream section. Thus, the downstream hollow tubular element preferably extends to the downstream end of the aerosol-generating article. When the downstream hollow tubular element extends to the downstream end of the aerosol-generating article, the downstream hollow tubular element may define a mouth-end cavity of the aerosol-generating article.

[0135] In certain embodiments, additional downstream hollow tubular elements may be provided such that the downstream section comprises two adjacent downstream hollow tubular elements downstream of the downstream filter segment.

[0136] The RTD of the downstream hollow tubular element may be 10 millimeters of water column or less, or 5 millimeters of water column or less, or 2.5 millimeters of water column or less, or 2 millimeters of water column or less. The RTD of the downstream hollow tubular element is preferably 1 millimeter of water column or less. The RTD of the downstream hollow tubular element may be at least 0 millimeters of water column, or at least 0.25 millimeters of water column, or at least 0.5 millimeters of water column, or at least 1 millimeter of water column.

[0137] Therefore, the air flow channel of the downstream hollow tubular element should not contain any components that would impede the longitudinal air flow. It is preferred that the flow channel is substantially empty, and it is particularly preferred that the flow channel is empty.

[0138] Preferably, the length of the downstream hollow tubular element may be at least 3 millimeters, more preferably at least 4 millimeters, more preferably at least 5 millimeters, more preferably at least 6 millimeters. The length of the downstream hollow tubular element is preferably less than 20 millimeters, more preferably less than 15 millimeters, more preferably less than 12 millimeters, more preferably less than 10 millimeters.

[0139] The lumen or cavity of the downstream hollow tubular element may have any cross-sectional shape. The lumen of the downstream hollow tubular element may have a circular cross-sectional shape.

[0140] The downstream hollow tubular element may comprise a paper-based material. The downstream hollow tubular element may comprise at least one paper layer. The paper may be very stiff paper. The paper may be crimped paper, such as crimped heat-resistant paper or crimped parchment paper. The downstream hollow tubular element may comprise cardboard. The downstream hollow tubular element may be a cardboard tube.

[0141] The downstream hollow tubular element can be a paper tube. The downstream hollow tubular element can be a tube formed from spirally wound paper. The downstream hollow tubular element can be formed from multiple layers of paper. The paper can have a basis weight of at least 50 grams per square meter, at least 60 grams per square meter, at least 70 grams per square meter, or at least 90 grams per square meter.

[0142] The downstream hollow tubular element may comprise a polymeric material. For example, the downstream hollow tubular element may comprise a polymeric film. The polymeric film may comprise a cellulose film. The downstream hollow tubular element may comprise low-density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers. Preferably, the downstream hollow tubular element comprises cellulose acetate tow. For example, in a preferred embodiment, the downstream hollow tubular element comprises a hollow acetate tube.

[0143] When the downstream hollow tubular element comprises cellulose acetate tow, the cellulose acetate tow may have a denier per filament of 2 to 4 and a total denier of 25 to 40.

[0144] If the downstream section further comprises an additional downstream hollow tubular element as described above, the additional downstream hollow tubular element may be formed from the same material as the downstream hollow tubular element or from a different material.

[0145] In certain preferred embodiments, the downstream section may include a ventilation zone at the location of the downstream hollow tubular element. In one example, this ventilation zone at the location of the downstream hollow tubular element may be provided in place of the ventilation zone at the location of the hollow tubular cooling element. In another example, the ventilation zone at the location of the downstream hollow tubular element may be provided in addition to the ventilation zone provided at the location of the hollow tubular cooling element.

[0146] A ventilation zone at a location along the downstream hollow tubular element may include a plurality of perforations through the circumferential wall of the downstream hollow tubular element. Preferably, a ventilation zone at a location along the downstream hollow tubular element includes at least one circumferential row of perforations. In some embodiments, a ventilation zone may include two circumferential rows of perforations. For example, the perforations may be formed online during manufacture of the aerosol-generating article. Preferably, each circumferential row of perforations includes between 8 and 30 perforations.

[0147] The aerosol-generating article may comprise one or more hollow tubular elements. The one or more hollow tubular elements may form part of a downstream section of the aerosol-generating article disposed downstream of the aerosol-forming substrate portion. The one or more hollow tubular elements may comprise one or both of hollow acetate tubing (HAT) and fine hollow acetate tubing (FHAT). Such hollow tubes may be made from cellulose acetate and are cylindrical components provided with a centrally disposed axial hole. The dimensions of the hollow tube, such as the outer diameter of the hollow tube and the outer diameter or diameter of the hole, may vary and can be designed according to the requirements of each product.

[0148] The HAT may have a length of 6 to 10 millimeters, preferably 7 to 9 millimeters, and more preferably about 8 millimeters. The HAT may be disposed downstream of the aerosol-forming substrate portion, preferably downstream of and directly abutting the aerosol-forming substrate portion. The HAT may function as one or more of an airflow cooling element and an airflow accelerating element.

[0149] The FHAT may be disposed downstream of the HAT, preferably downstream of and directly abutting the HAT. The inner diameter of the FHAT may be larger than the inner diameter of the HAT. For example, the inner diameter of the FHAT may be approximately twice the inner diameter of the HAT. The FHAT may function as an airflow slowdown element.

[0150] The aerosol-generating article may include a mouth-end filter. The mouth-end filter may be disposed downstream of the aerosol-forming substrate portion. The mouth-end filter may be disposed at the proximal end of the aerosol-generating article. The mouth-end filter may be disposed downstream of the FHAT and may directly abut the FHAT.

[0151] The mouth end filter may include a filter material. The filter material may be a filament material, such as cellulose acetate. The denier per filament may be 12. The denier of the filter material may be 12Y28.

[0152] The length of the mouth end filter along the longitudinal axis of the aerosol-generating article may be between 10 mm and 14 mm, preferably between 11 mm and 13 mm, and more preferably about 12 mm.

[0153] The withdrawal resistance of the mouth-end filter may be 1 to 100 millimeters of water column, preferably 2 to 50 millimeters of water column, more preferably 5 to 40 millimeters of water column, more preferably 10 to 30 millimeters of water column, more preferably 16 to 20 millimeters of water column, more preferably 17 to 19 millimeters of water column, and more preferably about 18 millimeters of water column. The withdrawal resistance of the mouth-end filter per millimeter of length along the longitudinal direction of the aerosol-generating article may be 0.1 to 20 millimeters of water column, preferably 0.2 to 10 millimeters of water column, more preferably 0.5 to 5 millimeters of water column or more, more preferably 1 to 2 millimeters of water column or more, more preferably 1.3 to 1.7 millimeters of water column, more preferably 1.4 to 1.6 millimeters of water column, and more preferably about 1.5 millimeters of water column.

[0154] The aerosol-generating article according to the present disclosure may further comprise an upstream section located upstream of the aerosol-forming substrate portion. The upstream section is preferably located immediately upstream of the aerosol-forming substrate portion. The upstream section preferably extends between the upstream end of the aerosol-generating article and the aerosol-forming substrate portion. The upstream section may include one or more upstream elements located upstream of the aerosol-forming substrate portion.

[0155] The aerosol-generating article of the present invention preferably comprises an upstream element located upstream of and adjacent to the aerosol-forming substrate portion. The upstream element advantageously prevents direct physical contact with the upstream end of the aerosol-forming substrate portion. Furthermore, the presence of the upstream element helps to prevent any loss of the substrate, which can be advantageous, for example, when the substrate contains particulate plant material.

[0156] Where the upstream segment of the aerosol-forming substrate portion includes shredded tobacco, such as tobacco cut filler, the upstream section or element thereof may additionally help to prevent loss of loose particles of tobacco from the upstream end of the article, which may be particularly important, for example, when the shredded tobacco has a relatively low density.

[0157] The upstream element may be a porous plug element. Preferably, the upstream element has a porosity of at least 50 percent along the longitudinal axis of the aerosol-generating article. More preferably, the upstream element has a porosity of between 50 percent and 90 percent along the longitudinal axis. The porosity of the upstream element along the longitudinal axis is defined as the ratio of the cross-sectional area of the material forming the upstream element to the internal cross-sectional area of the aerosol-generating article at the location of the upstream element.

[0158] The upstream element may be made of a porous material or may include a plurality of openings, which may be achieved, for example, by laser drilling, and which are preferably uniformly distributed across the cross section of the upstream element.

[0159] The porosity or permeability of the upstream element may advantageously be designed to provide an aerosol-generating article with a particular overall resistance to draw (RTD) without substantially affecting the filtration provided by other portions of the article.

[0160] The upstream element may be formed from a material that is impermeable to air. In such embodiments, the aerosol-generating article may be configured such that suitable venting means provided in the wrapper allows air to enter the aerosol-forming substrate portion.

[0161] In certain preferred embodiments of the present invention, it may be desirable to minimize the RTD of the upstream element. For example, this may be the case for an article intended to be inserted into the cavity of an aerosol-generating device, such that the aerosol-forming substrate is externally heated, as described herein. For such articles, it is desirable to provide the article with the lowest possible RTD, so that the majority of the consumer's RTD experience is provided by the aerosol-generating device, rather than the article.

[0162] The RTD of the upstream element may be less than 30 millimeters of water column, or less than 20 millimeters of water column, or less than 10 millimeters of water column, or less than 5 millimeters of water column, or less than 2 millimeters of water column. The RTD of the upstream element may be at least 0.1 millimeters of water column, or at least 0.25 millimeters of water column, or at least 0.5 millimeters of water column. Preferably, the upstream element has an RTD of less than 2 millimeters of water column per millimeter of length, more preferably less than 1.5 millimeters of water column per millimeter of length, more preferably less than 1 millimeter of water column per millimeter of length, more preferably less than 0.5 millimeters of water column per millimeter of length, more preferably less than 0.3 millimeters of water column per millimeter of length, and more preferably less than 0.2 millimeters of water column per millimeter of length.

[0163] Preferably, the combined RTD of the upstream section or upstream element thereof and the aerosol-forming substrate portion is less than 15 mm of water column, more preferably less than 12 mm of water column, more preferably less than 10 mm of water column.

[0164] In certain preferred embodiments, the upstream element is formed of a solid, cylindrical plug element having a filled cross-section. Such a plug element may be referred to as a "plain" element. The solid plug element may be porous as described above, but does not have a tubular configuration and therefore does not provide a longitudinal flow channel. Preferably, the solid plug element has a substantially uniform cross-section.

[0165] In other preferred embodiments, the upstream element is formed from a hollow tubular segment defining a longitudinal cavity that provides an unrestricted flow channel. In such embodiments, the upstream element may provide protection for the aerosol-forming substrate, as described above, while having a minimal effect on the overall resistance to draw (RTD) and filtration characteristics of the article.

[0166] Preferably, the diameter of the longitudinal cavity of the hollow tubular segment forming the upstream element is at least 3 millimeters, more preferably at least 3.5 millimeters, more preferably at least 4 millimeters, more preferably at least 4.5 millimeters. Preferably, the diameter of the longitudinal cavity is maximized to minimize the RTD of the upstream section or upstream element thereof.

[0167] Preferably, the wall thickness of the hollow tubular segment is less than 2 millimeters, more preferably less than 1.5 millimeters, more preferably less than 1 millimeter.

[0168] The upstream element of the upstream section may be made of any material suitable for use in an aerosol-generating article. The upstream element may be made of the same material as that used in one of the other components of the aerosol-generating article, such as, for example, the downstream filter segment or a hollow tubular cooling element. Suitable materials for forming the upstream element include filter material, ceramic, polymeric material, cellulose acetate, cardboard, zeolite, or an aerosol-forming substrate. The upstream element may include a plug of cellulose acetate. The upstream element may comprise a hollow acetate tube or a cardboard tube.

[0169] The upstream element is preferably formed from a heat resistant material, for example, a material that can withstand temperatures up to 350 degrees Celsius, to ensure that the upstream element is not adversely affected by the heating means for heating the aerosol-forming substrate.

[0170] The upstream section or upstream element thereof preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article, and preferably has an outer diameter of between 5 mm and 8 mm, more preferably between 5.25 mm and 7.5 mm, and even more preferably between 5.5 mm and 7 mm.

[0171] Preferably, the upstream section or element has a length of 2 to 10 mm, more preferably 3 to 8 mm, more preferably 2 to 6 mm, In a particularly preferred embodiment, the upstream section or element has a length of 5 mm.

[0172] The upstream section is preferably surrounded by a wrapper, such as plug wrap, which is preferably a stiff plug wrap, for example, a plug wrap having a basis weight of at least 80 grams per square meter, or at least 100 grams per square meter, or at least 110 grams per square meter, to provide structural rigidity to the upstream section.

[0173] The upstream section is preferably connected to the aerosol-forming substrate portion, and optionally to at least part of the downstream section, by an outer wrapper.

[0174] The aerosol-generating article may comprise an upstream section including a front plug. The front plug may be disposed upstream of the aerosol-forming substrate portion and may directly abut the aerosol-forming substrate portion. The front plug may be disposed at the distal end of the aerosol-generating article. The front plug may comprise a filter material. The length of the front plug along the longitudinal axis of the aerosol-generating article may be between 1 mm and 10 mm, preferably between 3 mm and 7 mm, more preferably between 4 mm and 6 mm, and more preferably about 5 mm. The front plug may be in the form of a complete cylinder.

[0175] The ratio of the thickness of the substrate wrapper to the diameter of the front plug may be in the range of 0.007 to 0.03, preferably 0.015 to 0.027, more preferably 0.022 to 0.024.

[0176] The outer diameter of the front plug may differ from the outer diameter of the substrate wrapper surrounding the aerosol-forming substrate portion by less than 5 percent, preferably less than 3 percent, more preferably less than 1 percent; optionally, the outer diameter of the front plug is 7.1 millimeters.

[0177] The forward plug may be surrounded by a forward plug wrapper, and the ratio of the thickness of the forward plug wrapper to the thickness of the substrate wrapper may be 0.7 or less, more preferably 0.5 or less, more preferably 0.3 or less, more preferably 0.2 or less.

[0178] No portion of the front plug may be surrounded by a substrate wrapper.

[0179] The front plug may have a withdrawal resistance of 1 to 150 mm of water column, preferably 1 to 50 mm of water column, more preferably 1 to 20 mm of water column, more preferably 1 to 10 mm of water column. The front plug may have a withdrawal resistance of about 10 mm of water column or less.

[0180] The front plug may help maintain the cleanliness of the aerosol-generating device by trapping slurry within the consumable. The front plug may prevent the aerosol-forming substrate or heating element from falling out of the aerosol-generating article.

[0181] Aerosol-generating articles according to the invention may have an overall length of at least 40 millimeters, or at least 50 millimeters, or at least 60 millimeters.

[0182] The overall length of an aerosol-generating article according to the present invention may be 90 millimeters or less, or 85 millimeters or less, or 80 millimeters or less.

[0183] In some embodiments, the total length of the aerosol-generating article is preferably 50 millimeters to 90 millimeters, more preferably 60 millimeters to 90 millimeters, and even more preferably 70 millimeters to 90 millimeters. In other embodiments, the total length of the aerosol-generating article is preferably 50 millimeters to 85 millimeters, more preferably 60 millimeters to 85 millimeters, and even more preferably 70 millimeters to 85 millimeters. In further embodiments, the total length of the aerosol-generating article is preferably 50 millimeters to 80 millimeters, more preferably 60 millimeters to 80 millimeters, and even more preferably 70 millimeters to 80 millimeters. In an exemplary embodiment, the total length of the aerosol-generating article is 75 millimeters.

[0184] In some embodiments, the total length of the aerosol-generating article is preferably between 40 millimeters and 70 millimeters, more preferably between 45 millimeters and 70 millimeters. In other embodiments, the total length of the aerosol-generating article is preferably between 40 millimeters and 60 millimeters, more preferably between about 45 millimeters and about 60 millimeters. In further embodiments, the total length of the aerosol-generating article is preferably between 40 millimeters and 50 millimeters, more preferably between 45 millimeters and 50 millimeters. In an exemplary embodiment, the total length of the aerosol-generating article is about 45 millimeters.

[0185] Preferably, the aerosol-generating article has an outer diameter of at least about 5 millimeters. More preferably, the aerosol-generating article has an outer diameter of at least 5.25 millimeters. Even more preferably, the aerosol-generating article has an outer diameter of at least 5.5 millimeters.

[0186] Preferably, the aerosol-generating article has an outer diameter of 8 millimeters or less. More preferably, the aerosol-generating article has an outer diameter of 7.5 millimeters or less. Even more preferably, the aerosol-generating article has an outer diameter of 7 millimeters or less.

[0187] The aerosol-generating article may have an outer diameter of 5 mm to 8 mm, or 5 mm to 7.5 mm, or 5 mm to 7 mm, or 5.25 mm to 8 mm, or 5.25 mm to 7.5 mm, or 5.25 mm to 7 mm, or 5.5 mm to 8 mm, or 5.5 mm to 7.5 mm, or 5.5 mm to 7 mm.

[0188] The outer diameter of the aerosol-generating article may be substantially constant along the entire length of the article. Alternatively, different portions of the aerosol-generating article may have different outer diameters.

[0189] Preferably, the overall RTD of the aerosol-generating article is at least 10 millimeters of water column. For example, the overall RTD of the aerosol-generating article may be at least 20 millimeters of water column, at least 30 millimeters of water column, at least 35 millimeters of water column, or at least 40 millimeters of water column.

[0190] The overall RTD of the aerosol-generating article may be 70 millimeters of water column or less. For example, the overall RTD of the aerosol-generating article may be 65 millimeters of water column or less, 60 millimeters of water column or less, or 55 millimeters of water column or less, or 50 millimeters of water column or less.

[0191] The overall RTD of the aerosol-generating article may be between 10 millimeters of water column and 70 millimeters of water column. For example, the overall RTD of the aerosol-generating article may be between 20 millimeters of water column and 65 millimeters of water column, between 30 millimeters of water column and 60 millimeters of water column, between 35 millimeters of water column and 55 millimeters of water column, or between 40 millimeters of water column and 50 millimeters of water column.

[0192] In a particularly preferred embodiment, one or more of the components of the aerosol-generating article are individually enclosed by their own wrapper.

[0193] In one embodiment, the aerosol-forming substrate portion and mouthpiece element are individually wrapped. The upstream element, the aerosol-forming substrate portion, and its surrounding substrate wrapper and hollow tubular element are then combined together with an outer wrapper. They are then combined with the downstream filter element, which has its own wrapper, by tipping paper.

[0194] Preferably, at least one of the components of the aerosol-generating article is enclosed in a hydrophobic wrapper.

[0195] The term "hydrophobicity" refers to a surface that exhibits water-repellent properties. One useful way to determine this is to measure the water contact angle. The "water contact angle" is the angle traditionally measured through a liquid where the liquid / vapor interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid via Young's equation. Hydrophobicity or water contact angle may be determined by utilizing the TAPPI T558 test method, and the results are expressed as interfacial contact angles, reported in degrees, which can range from approximately zero to approximately 180 degrees.

[0196] In preferred embodiments, the hydrophobic wrapper comprises a paper layer having a water contact angle of about 30 degrees or greater, preferably about 35 degrees or greater, or about 40 degrees or greater, or about 45 degrees or greater.

[0197] By way of example, the paper layer may comprise PVOH (polyvinyl alcohol) or silicone. The PVOH may be applied to the paper layer as a surface coating, or the paper layer may comprise a surface treatment that includes PVOH or silicone.

[0198] The aerosol-generating article may comprise a tipping wrapper at least partially surrounding the aerosol-forming substrate portion and at least partially surrounding one or more portions of the aerosol-generating article adjacent the aerosol-forming substrate portion, wherein the one or more adjacent portions may comprise a front plug.

[0199] The tipping wrapper can be conventional cigarette paper. The tipping wrapper can have a basis weight of less than 50 grams per square meter. The tipping wrapper may have a thickness of less than 70 micrometers or less than 50 micrometers. The tipping wrapper can have a thickness of about 65 micrometers and a basis weight of about 45 grams per square meter.

[0200] The tipping wrapper can be thinner than the base wrapper. The ratio of the thickness of the tipping wrapper to the thickness of the base wrapper can be 0.7 or less, more preferably 0.5 or less, more preferably 0.3 or less, more preferably 0.2 or less.

[0201] The aerosol-generating article may include vent holes. The vent holes may promote aerosol nucleation. The vent holes may assist in cooling the airflow. The vent holes may be provided within the FHAT. The FHAT may include 11 vent holes, each having a diameter of 0.11 millimeters.

[0202] The total draw resistance of the aerosol-generating article may be from 5 mm to 200 mm of water column, preferably from 10 mm to 150 mm of water column, more preferably from 20 mm to 100 mm of water column, more preferably from 80 mm to 80 mm of water column, more preferably from 40 mm to 60 mm of water column, more preferably from 45 mm to 55 mm of water column, more preferably about 48 mm of water column.

[0203] The aerosol-generating article may have a cylindrical shape.The aerosol-forming substrate portion may have a cylindrical shape.

[0204] The aerosol-generating article may comprise, from the proximal end to the distal end of the article, a mouth-end filter, one or more intermediate elements, an aerosol-forming substrate portion, and optionally a front plug. The one or more intermediate elements may include one or more of a HAT, a FHAT, and a PLA plug. The overall length of the article may be about 45 millimeters, and the length of the aerosol-forming substrate portion may be about 11 millimeters. The tipping wrapper may surround the entire article or only a portion of it.

[0205] The aerosol-forming substrate portion includes a susceptor. The susceptor is at least partially surrounded by the aerosol-forming substrate. The susceptor may be completely surrounded by the aerosol-forming substrate. The susceptor may extend along substantially the entire length of the aerosol-forming substrate portion. This may provide optimized heat distribution within the aerosol-forming substrate when the susceptor is heated. The susceptor may include a flat, planar susceptor portion. The susceptor may be a flat, planar susceptor strip. The susceptor may comprise a metal or alloy. The susceptor may comprise aluminum.

[0206] As used herein, the term "flat planar" refers to a generally cubic shape having a height that is significantly less than its width and length. For example, the width and length may each be at least twice the height of the cube. The height of a flat planar cube may also be referred to as the thickness of the susceptor, or the thickness of the flat planar susceptor portion.

[0207] The susceptor element may generally have a thickness of 0.01 millimeters to 2 millimeters, for example, 0.5 millimeters to 2 millimeters. In some embodiments, the susceptor element preferably has a thickness of 10 micrometers to 500 micrometers, more preferably 10 micrometers to 100 micrometers.

[0208] The susceptor may have a thickness of about 35 micrometers to about 85 micrometers. The susceptor may have a thickness of about 45 micrometers to about 75 micrometers. The susceptor may have a thickness of about 55 micrometers to about 65 micrometers.

[0209] The susceptor may be an elongated susceptor disposed substantially longitudinally within the aerosol-forming substrate portion.

[0210] When used to describe a susceptor, the term "elongated" means that the susceptor has a length dimension that is greater than its width dimension or its thickness dimension, for example, greater than twice its width dimension or its thickness dimension.

[0211] The susceptor may be disposed substantially longitudinally within the aerosol-forming substrate portion. This means that the length dimension of the elongated susceptor is disposed approximately parallel to the longitudinal axis of the aerosol-forming substrate, for example, within ±10 degrees of parallel to the longitudinal axis of the aerosol-forming substrate. The elongated susceptor may be positioned at a radially central position within the aerosol-forming substrate portion and may extend along the longitudinal axis of the aerosol-forming substrate portion.

[0212] The susceptor may be in the form of a pin, rod, strip, or blade.

[0213] The susceptor may have a length of about 5 millimeters to about 15 millimeters, for example, about 6 millimeters to about 12 millimeters, more preferably about 8 millimeters to about 10 millimeters. The susceptor may have a length of about 11 millimeters.

[0214] The susceptor may have a width of at least about 1 millimeter, more preferably at least about 2 millimeters. Typically, the susceptor may have a width of up to 8 millimeters, preferably no more than about 6 millimeters.

[0215] The elongated susceptor element preferably has a length equal to or shorter than the length of the aerosol-forming substrate portion in which it is incorporated. The length of the susceptor element may be 99% or less, 95% or less, 90% or less, 85% or less, 80% or less, 70% or less, 60% or less, or 50% or less of the length of the aerosol-forming substrate portion in which it is incorporated. The length of the susceptor element may be 70% to 99%, preferably 75% to 95%, more preferably 80% to 95%, and more preferably 85% to 95% of the length of the aerosol-forming substrate portion in which it is incorporated.

[0216] If the susceptor has a uniform cross-section, for example, a circular cross-section, it can have a width or diameter of from about 1 millimeter to about 5 millimeters.

[0217] When the susceptor has the form of a strip or blade, the strip or blade may have a rectangular cross section, preferably having a width of about 2 millimeters to about 8 millimeters, more preferably about 3 millimeters to about 6 millimeters. A susceptor in the form of a strip or blade may have a width of about 4 millimeters.

[0218] The elongated susceptor may have a thickness of about 57 micrometers to about 63 micrometers. Even more preferably, the elongated susceptor may have a thickness of about 58 micrometers to about 62 micrometers. Most preferably, the elongated susceptor has a thickness of about 60 micrometers.

[0219] The withdrawal resistance of the aerosol-forming substrate portion may be 0.1 mm to 200 mm of water column, preferably 1 mm to 100 mm of water column, more preferably 5 mm to 40 mm of water column, more preferably 10 mm to 30 mm of water column, more preferably 17 mm to 29 mm of water column, preferably 20 mm to 26 mm of water column, more preferably about 23 mm of water column. The withdrawal resistance of the aerosol-forming substrate portion may be 18 mm of water column or more. The withdrawal resistance of the aerosol-forming substrate portion may be 23 mm of water column or more.

[0220] Having a low withdrawal resistance of the aerosol-forming substrate portion, for example, less than 10 millimeters of water column, may mean that there is only little interaction between the airflow and the aerosol-forming substrate, so that aerosolization is only slight. Having a high withdrawal resistance of the aerosol-forming substrate portion, for example, more than 30 millimeters of water column, may mean that the aerosol-forming substrate portion has a substantial impact on the overall withdrawal resistance of the aerosol-generating article. The withdrawal resistance of the aerosol-forming substrate portion may vary to some extent from article to article due to manufacturing tolerances. Reducing the impact of the aerosol-forming substrate portion on the overall withdrawal resistance of the aerosol-generating article may make the withdrawal resistance more consistent between different articles.

[0221] The resistance to drawing of the aerosol-forming substrate portion per millimeter of length along the longitudinal axis of the aerosol-generating article may be from 0.1 to 20 millimeters of water column, preferably from 0.2 to 10 millimeters of water column, more preferably from 1 to 5 millimeters of water column, more preferably from 1.7 to 2.5 millimeters of water column, more preferably from 1.9 to 2.3 millimeters of water column. The resistance to drawing of the aerosol-forming substrate portion per millimeter of length along the longitudinal axis of the aerosol-generating article may be about 2.1 millimeters of water column.

[0222] The total length of the aerosol-forming substrate portion in a direction along the longitudinal axis of the aerosol-generating article may be from 1 mm to 30 mm, preferably from 5 mm to 16 mm, more preferably from 9 mm to 13 mm, more preferably from 10 mm to 12 mm. The total length of the aerosol-forming substrate portion in a direction along the longitudinal axis of the aerosol-generating article may be 11 mm or less.

[0223] The total length of the aerosol-generating article may be from 10 mm to 150 mm, preferably from 20 mm to 1000 mm, more preferably from 30 mm to 80 mm, more preferably from 40 mm to 50 mm, more preferably from 43 mm to 47 mm, more preferably about 45 mm. The length of the aerosol-forming substrate along the longitudinal axis of the article may be from 22% to 26% of the total length of the aerosol-generating article, preferably about 24% of the total length of the aerosol-generating article.

[0224] The ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article may be at least 0.20. Preferably, the ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article is at least 0.25. More preferably, the ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article is at least 0.30.

[0225] Preferably, the ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article is 0.60 or less. Preferably, the ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article is 0.55 or less. More preferably, the ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article is 0.50 or less.

[0226] In some embodiments, the ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article is 0.20 to 0.60, preferably 0.20 to 0.55, more preferably 0.20 to 0.50. In other embodiments, the ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article is 0.25 to 0.60, preferably 0.25 to 0.55, more preferably 0.25 to 0.50. In a further embodiment, the ratio between the total length of the aerosol-forming substrate portion and the total length of the aerosol-generating article is 0.30 to 0.60, preferably 0.30 to 0.55, more preferably 0.30 to 0.50.

[0227] As used herein, the terms "external diameter" and "outer diameter" of an aerosol-generating article or component thereof may be calculated as the average of multiple measurements of the diameter of the aerosol-generating article or component thereof taken at different positions along the length of the aerosol-generating article or component thereof.

[0228] Preferably, the aerosol-generating article has an outer diameter of at least about 5 millimeters. More preferably, the aerosol-generating article has an outer diameter of at least 5.25 millimeters. Even more preferably, the aerosol-generating article has an outer diameter of at least 5.5 millimeters.

[0229] Preferably, the aerosol-generating article has an outer diameter of 8 millimeters or less. More preferably, the aerosol-generating article has an outer diameter of 7.5 millimeters or less. Even more preferably, the aerosol-generating article has an outer diameter of 7 millimeters or less.

[0230] Preferably, the aerosol-generating article has a substantially circular cross-section. Preferably, the aerosol-generating article has a substantially uniform cross-section along the entire length of the aerosol-generating article.

[0231] The total density of the aerosol-forming substrate portions may be greater than 0.71 milligrams per cubic millimeter. The total density of the aerosol-forming substrate portions may be equal to or greater than 0.715 milligrams per cubic millimeter. The total density of the aerosol-forming substrate portions may be equal to or greater than 0.720 milligrams per cubic millimeter. The total density of the aerosol-forming substrate portions may be about 0.725 milligrams per cubic millimeter.

[0232] For example, the substrate wrapper may enclose a cylindrical volume having a diameter of 6.77 millimeters and a length of 11 millimeters, i.e., a volume of 396 cubic millimeters. The volume may be filled with the aerosol-forming substrate and susceptor. The total mass of the aerosol-forming substrate within the aerosol-forming substrate portion may be 266 milligrams, and the total mass of the susceptor material within the aerosol-forming substrate portion may be 21.2 milligrams. The total density of the aerosol-forming substrate portion then corresponds to 287.2 milligrams divided by 396 cubic millimeters, i.e., 0.725 milligrams per cubic millimeter.

[0233] The total density of the aerosol-generating article at the longitudinal axis of the aerosol-forming substrate portion, taking into account the mass and volume of the substrate wrapper and one or more optional additional wrappers surrounding the substrate wrapper, may be about 0.66 milligrams per cubic millimeter.

[0234] The ratio of the total density of the aerosol-forming substrate portion divided by the total density of the aerosol-generating article at a position along the longitudinal axis of the aerosol-forming substrate portion may be greater than 1.0, preferably greater than 1.05, and more preferably greater than 1.09.

[0235] At least 70% by volume, preferably at least 75% by volume, more preferably at least about 79% by volume of the interior volume of the aerosol-forming substrate portion may be filled with the aerosol-forming substrate and one or more susceptor elements.

[0236] Less than 30 volume percent, preferably less than 25 volume percent, and more preferably less than about 21 volume percent of the interior volume of the aerosol-forming substrate portion may be empty.

[0237] The total mass of the aerosol-forming substrate in the aerosol-forming substrate portion may be less than 300 milligrams, preferably less than 290 milligrams. The total mass of the aerosol-forming substrate in the aerosol-forming substrate portion may be about 266 milligrams. The total mass of the aerosol-forming substrate in the aerosol-forming substrate portion may be between 10 milligrams and 3000 milligrams, preferably between 50 milligrams and 1000 milligrams, more preferably between 100 milligrams and 500 milligrams, more preferably between 200 milligrams and 400 milligrams, more preferably between 250 milligrams and 350 milligrams, more preferably between 260 milligrams and 270 milligrams, more preferably between 263 milligrams and 269 milligrams.

[0238] The aerosol-forming substrate portion includes an aerosol-forming substrate and a susceptor. The total mass of the susceptor material in the aerosol-forming substrate portion may be 1 milligram to 100 milligrams, preferably 5 milligrams to 50 milligrams, more preferably 10 milligrams to 40 milligrams, more preferably 15 milligrams to 25 milligrams, more preferably 20 milligrams to 23 milligrams, and more preferably 20.5 milligrams to 21.7 milligrams.

[0239] The aerosol-forming substrate portion may include an aerosol-forming substrate and a susceptor, and the total mass of the susceptor material in the aerosol-forming substrate portion may be between 20.5 milligrams and 21.7 milligrams, and the total mass of the aerosol-forming substrate in the aerosol-forming substrate portion may be between 263 milligrams and 269 milligrams.

[0240] The density of the aerosol-forming substrate may be greater than 800 kilograms per cubic meter, preferably greater than 825 kilograms per cubic meter, more preferably about 842 kilograms per cubic meter.

[0241] The aerosol-forming substrate may be provided in the form of a sheet. The sheet of aerosol-forming substrate may be collected following insertion into the aerosol-forming substrate portion. The density of the sheet of aerosol-forming substrate may be determined by dividing the basis weight of the sheet by the thickness of the sheet before collecting the sheet.

[0242] The aerosol-forming substrate may be provided in the form of an assemblage of sheets of homogenised tobacco material.

[0243] The sheet of homogenized tobacco material may have a basis weight of less than 210 grams per square meter, preferably less than 200 grams per square meter, and more preferably about 192 grams per square meter.

[0244] The sheet of homogenized tobacco material may have a thickness of greater than 215 micrometers, preferably greater than 220 micrometers, and more preferably about 228 micrometers.

[0245] The homogenized tobacco material sheet may be a molded sheet. The homogenized tobacco material may contain tobacco particles having an average particle size (D95) of more than 50 micrometers, preferably between 50 micrometers and less than 100 micrometers, more preferably between 60 micrometers and 80 micrometers, more preferably between 65 micrometers and 75 micrometers, and more preferably about 70 micrometers, prior to the molding process. This tobacco particle size (D95) may result in a rough surface of the sheet. This may result in an increase in the surface area of the sheet. The increased surface may improve aerosolization. This may be particularly advantageous when the total mass of the aerosol-forming substrate within the aerosol-forming substrate portion is reduced. As used herein, the term "average particle size (D95)" is used to refer to the volume-based median of the particle size distribution and is the particle diameter value at 95% of the cumulative distribution. The particle size of the particles may be analyzed by laser diffraction.

[0246] The aerosol-forming substrate can include tobacco material, on a dry weight basis, from about 1 percent to about 5 percent binder, and from about 10 percent to about 30 percent glycerin.

[0247] The aerosol-forming substrate portion may define a substantially cylindrical shape. The cylindrical shape of the aerosol-forming substrate portion may have a diameter within the range of about 3 mm to about 10 mm, preferably about 6 mm to about 8 mm, more preferably about 6.5 mm to about 7.5 mm, more preferably about 6.6 mm to about 7.0 mm, more preferably about 6.7 mm to about 6.9 mm, and more preferably about 6.75 mm to about 6.85 mm. The cylindrical shape of the aerosol-forming substrate portion may have a diameter within the range of about 6.8 mm to about 7.1 mm, or about 6.8 mm to about 7.0 mm.

[0248] The present invention further relates to a package comprising a plurality of aerosol-generating articles, each aerosol-generating article in the package being an aerosol-generating article as described herein.

[0249] The present invention further relates to an aerosol generation system comprising an aerosol-generating article as described herein and an aerosol-generating device. The aerosol-generating device may comprise a heating chamber configured to at least partially insert the aerosol-generating article into the heating chamber. The aerosol-generating device may comprise an internal heating element arranged to be inserted into the aerosol-generating article when the aerosol-generating article is at least partially inserted into the heating chamber. The aerosol-generating device may comprise an inductor coil. The inductor coil may at least partially surround the periphery of the heating chamber. The inductor coil may be arranged to coaxially surround the heating chamber. The inductor coil may be arranged to inductively heat a susceptor element. The susceptor element may be part of the internal heating element of the aerosol-generating device. The susceptor element may be part of the aerosol-generating article. The inductor coil may be arranged to inductively heat a susceptor of the aerosol-generating article when the aerosol-generating article is at least partially inserted into the heating chamber.

[0250] As used herein, the term "aerosol-forming substrate" refers to a substrate capable of releasing volatile compounds that can form an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. The aerosol-forming substrate may be in solid or liquid form. The aerosol-forming substrate may be solid or liquid, or may contain both solid and liquid components. The aerosol-forming substrate may be part of an aerosol-generating article. The terms "aerosol" and "vapor" are used interchangeably.

[0251] The aerosol-forming substrate may comprise one or more of tobacco, nicotine, an aerosol-generating film, a gel composition, and a flavoring. The aerosol-forming substrate may also comprise homogenized tobacco materials such as cast leaf, aerosol-generating films, and gel compositions.

[0252] The aerosol-forming substrate may comprise one or more aerosol formers. The aerosol former may be any suitable known compound or mixture of compounds that promotes the formation of a dense, stable aerosol during use. The aerosol former may promote the aerosol to be substantially resistant to thermal decomposition at temperatures typically encountered during use of the aerosol-generating article. Suitable aerosol formers include, for example, polyhydric alcohols (e.g., triethylene glycol, 1,3-butanediol, propylene glycol, glycerin, etc.), esters of polyhydric alcohols (e.g., glycerol mono-, di-, or triacetate, etc.), aliphatic esters of mono-, di-, or polycarboxylic acids (e.g., dimethyl dodecanedioate, dimethyl tetradecanedioate, etc.), and combinations thereof. Preferably, the one or more aerosol formers comprise one or both of glycerol and propylene glycol. The one or more aerosol formers may consist of one or both of glycerol and propylene glycol. Preferably, the aerosol-forming substrate comprises glycerol. The terms "glycerin" and "glycerol" are used interchangeably herein.

[0253] The aerosol-forming substrate may comprise 80 weight percent or less of aerosol formers, based on the dry weight of the aerosol-forming substrate. The aerosol-forming substrate may comprise 60 weight percent or less of aerosol formers, based on the dry weight of the aerosol-forming substrate. The aerosol-forming substrate may comprise 40 weight percent or less of aerosol formers, based on the dry weight of the aerosol-forming substrate. The aerosol-forming substrate may comprise 20 weight percent or less, or 15 weight percent or less of aerosol formers, based on the dry weight of the aerosol-forming substrate.

[0254] The aerosol-forming substrate may comprise from 5 weight percent to 80 weight percent, or from 5 weight percent to 60 weight percent, or from 5 weight percent to 40 weight percent, or from 5 weight percent to 20 weight percent, or from 5 weight percent to 15 weight percent, or from 7 weight percent to 80 weight percent, or from 7 weight percent to 60 weight percent, or from 7 weight percent to 40 weight percent, or from 7 weight percent to 20 weight percent, or from 7 weight percent to 15 weight percent, or from 10 weight percent to 80 weight percent, or from 10 weight percent to 60 weight percent, or from 10 weight percent to 40 weight percent, or from 10 weight percent to 20 weight percent, or from 10 weight percent to 15 weight percent of the aerosol former, based on the dry weight of the aerosol-forming substrate.

[0255] The aerosol-forming substrate may comprise a tobacco material. The aerosol-forming substrate may comprise a shredded tobacco material. For example, the shredded tobacco material may be in the form of cut filler, as described in more detail below. Alternatively, the shredded tobacco material may be in the form of a shredded sheet of homogenized tobacco material. Suitable homogenized tobacco materials for use in the present invention are described below.

[0256] In the context of this specification, the term "cut filler" is used to refer to a blend of chopped plant material, such as tobacco plant material, including, inter alia, one or more of leaf laminae, processed stems and veins, and homogenized plant material.

[0257] Cut filler may also include other cuts, filler tobacco, or casings.

[0258] Preferably, the cut filler comprises at least 25 percent plant leaf lamina, more preferably at least 50 percent plant leaf lamina, even more preferably at least 75 percent plant leaf lamina, and most preferably at least 90 percent plant leaf lamina. Preferably, the plant material is one of tobacco, mint, tea, and cloves. Most preferably, the plant material is tobacco. However, the present invention is equally applicable to other plant materials capable of releasing a substance upon heating that can then form an aerosol.

[0259] Preferably, the cut filler comprises tobacco plant material including the blades of one or more of bright tobacco, dark tobacco, aromatic tobacco, and filler tobacco. For purposes of the present invention, the term "tobacco" describes any plant of the genus Nicotiana.

[0260] The cut filler suitable for use in the present invention may generally be similar to the cut filler used in conventional smoking articles. The cut width of the cut filler may preferably be 0.3 mm to 2.0 mm, or 0.5 mm to 1.2 mm, or 0.6 mm to 0.9 mm.

[0261] Preferably, the strands have a length of from about 10 millimeters to about 40 millimeters, and the strands are then aligned to form the aerosol-forming substrate portion.

[0262] In a preferred embodiment, the weight of the cut filler is 80 milligrams to 400 milligrams, preferably 120 milligrams to 250 milligrams, and more preferably 150 milligrams to 200 milligrams. This amount of cut filler is typically sufficient material for forming an aerosol.

[0263] Preferably, the cut filler is soaked with the aerosol former. Soaking of the cut filler can be accomplished by spraying or other suitable application methods. The aerosol former can be added to the blend during preparation of the cut filler. For example, the aerosol former can be applied to the blend in a direct conditioning casing cylinder (DCCC). Conventional machinery can be used to add the aerosol former to the cut filler. Suitable aerosol formers can be those described herein. Preferably, the aerosol former in the cut filler comprises one or both of glycerol and propylene glycol. The aerosol former can consist of glycerol or propylene glycol, or a combination of glycerol and propylene glycol.

[0264] The aerosol-forming substrate may comprise homogenized plant material, for example homogenized tobacco material.

[0265] As used herein, the term "homogenized plant material" encompasses any plant material formed by agglomeration of plant particles. For example, a sheet or web of homogenized plant material for the aerosol-forming substrate of the present invention may be formed by agglomerating particles of plant material obtained by grinding, crushing, or pulverizing the plant material. The homogenized plant material may be produced by casting, extrusion, a papermaking process, or any other suitable process known in the art. The homogenized plant material may be provided in any suitable form.

[0266] In some embodiments, the homogenized plant material may be in the form of one or more sheets. The term "sheet" as used herein with respect to the present invention describes a laminar element having a width and length that is significantly greater than its thickness.

[0267] The homogenized plant material may be in the form of a plurality of pellets or granules.

[0268] The homogenized plant material may be in the form of multiple strands, pieces, or fragments. As used herein, the term "strand" describes an elongated element of material having a length substantially greater than its width and thickness. The term "strand" should be considered to encompass pieces, fragments, and any other homogenized plant material having a similar morphology. Strands of homogenized plant material may be formed from a sheet of homogenized plant material, for example, by cutting or shredding, or by other methods, such as extrusion methods.

[0269] As noted above, when the homogenized plant material is in the form of one or more sheets, the sheets may be produced by a casting process. Alternatively, the sheets of homogenized plant material may be produced by a papermaking process.

[0270] One or more sheets as described herein may each individually have a thickness of from 100 micrometers to 600 micrometers, preferably from 150 micrometers to 300 micrometers, and most preferably from 200 micrometers to 250 micrometers. Individual thickness refers to the thickness of an individual sheet, and combined thickness refers to the total thickness of all sheets that make up the aerosol-forming substrate.

[0271] One or more of the sheets described herein may each individually have a basis weight of from 100 grams per square meter to 600 grams per square meter.

[0272] One or more sheets as described herein may each individually have a density of from 0.3 grams per cubic centimeter to 1.3 grams per cubic centimeter, preferably from 0.7 grams per cubic centimeter to 1.0 grams per cubic centimeter.

[0273] One or more of the sheets described herein may be one or more of the following: crimped, folded, gathered, pleated.

[0274] One or more sheets of homogenized plant material may be cut into strands, as mentioned above. In such embodiments, the aerosol-forming substrate comprises a plurality of strands of homogenized plant material. The strands may be used to form plugs. Typically, the width of such strands is about 5 millimeters, about 4 millimeters, about 3 millimeters, or about 2 millimeters or less. The length of the strands may be greater than about 5 millimeters, about 5 millimeters to about 15 millimeters, about 8 millimeters to about 12 millimeters, or about 12 millimeters. Preferably, the strands have substantially the same length as each other.

[0275] The homogenized plant material may contain, on a dry weight basis, 2.5 weight percent to 95 weight percent plant particles, or 5 weight percent to 90 weight percent plant particles, or 10 weight percent to 80 weight percent plant particles, or 15 weight percent to 70 weight percent plant particles, or 20 weight percent to 60 weight percent plant particles, or 30 weight percent to 50 weight percent plant particles.

[0276] In certain embodiments of the present invention, the homogenized plant material is a homogenized tobacco material comprising tobacco particles. The sheets of homogenized tobacco material used in such embodiments of the present invention may have a tobacco content of at least about 40 weight percent on a dry weight basis, more preferably at least about 50 weight percent on a dry weight basis, more preferably at least about 70 weight percent on a dry weight basis, and most preferably at least about 90 weight percent on a dry weight basis.

[0277] For purposes of the present invention, the term "tobacco particles" refers to particles of any plant material of the Nicotiana species. The term "tobacco particles" encompasses ground or powdered tobacco lamina, ground or powdered tobacco stems, tobacco dust, tobacco fines, and other particulate tobacco by-products formed during tobacco processing, handling, and shipping. In preferred embodiments, the tobacco particles are derived substantially entirely from tobacco lamina. In contrast, isolated nicotine and nicotine salts, although tobacco-derived compounds, are not considered tobacco particles for purposes of the present invention and are not included in the proportion of particulate plant material.

[0278] In a preferred embodiment, the aerosol-forming substrate comprises a strand of homogenized tobacco material, the strand weighing between 50 milligrams and 2000 milligrams, preferably between 80 milligrams and 400 milligrams, more preferably between 120 milligrams and 250 milligrams, and more preferably between 150 milligrams and 200 milligrams. This amount of strand of homogenized tobacco material typically provides sufficient material for the formation of an aerosol.

[0279] The aerosol-forming substrate may be in the form of an aerosol-generating film comprising a cellulosic film-forming agent, nicotine, and an aerosol former. The aerosol-generating film may further comprise a cellulosic reinforcing agent. The aerosol-generating film may further comprise water, preferably up to about 30 weight percent water.

[0280] The term "film" as used herein is used to describe a solid layered element having a thickness smaller than its width or length. The film may be self-supporting. In other words, even if the film is obtained by casting a film-forming formulation on a support surface, it may have cohesive and mechanical properties that allow it to be separated from the support surface. Alternatively, the film may be placed on a support or sandwiched between other materials. This may enhance the mechanical stability of the film.

[0281] The aerosol-generating film may comprise one or more aerosol formers as described herein; preferably, the aerosol former comprises or is glycerin. The aerosol-generating film may have an aerosol-former content of at least 5 weight percent on a dry weight basis. The aerosol-generating film may have an aerosol-former content of at least 15 weight percent on a dry weight basis. The aerosol-generating film may have an aerosol-former content of at least 20 weight percent on a dry weight basis. The aerosol-generating film may have an aerosol-former content of at least 30 weight percent on a dry weight basis. Preferably, the aerosol-generating film has an aerosol-former content of at least 40 weight percent on a dry weight basis. More preferably, the aerosol-generating film has an aerosol-former content of at least 45 weight percent on a dry weight basis. More preferably, the aerosol-generating film has an aerosol-former content of at least 50 weight percent on a dry weight basis.

[0282] Preferably, the aerosol-generating film has an aerosol-forming content of 80 weight percent or less on a dry weight basis. More preferably, the aerosol-generating film has an aerosol-forming content of 75 weight percent or less on a dry weight basis. More preferably, the aerosol-generating film has an aerosol-forming content of 70 weight percent or less on a dry weight basis.

[0283] In the context of the present invention, the term "cellulosic film former" is used to describe a cellulose polymer that has the ability to form a continuous film by itself or in the presence of an auxiliary thickener.

[0284] Preferably, the cellulosic film former is selected from the group consisting of hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), ethylcellulose (EC), hydroxyethyl methylcellulose (HEMC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), and combinations thereof.

[0285] More preferably, the cellulosic film-forming agent is selected from the group consisting of hydroxypropylmethylcellulose (HPMC), methylcellulose (MC), ethylcellulose (EC), and combinations thereof.

[0286] In a particularly preferred embodiment, the cellulosic film-forming agent is HPMC.

[0287] The aerosol-generating film may have a cellulosic film-forming agent content of 10 to 40 weight percent, or 15 to 35 weight percent, or 20 to 30 weight percent on a dry weight basis.

[0288] Preferably, the aerosol-generating film further comprises a cellulosic reinforcing agent, preferably selected from the group consisting of cellulose fibers, microcrystalline cellulose (MCC), cellulose powder, and combinations thereof.

[0289] The aerosol-generating film may have a cellulosic reinforcing agent content of 0.5 weight percent to 40 weight percent on a dry weight basis, or 5 weight percent to 30 weight percent on a dry weight basis, or 10 weight percent to 25 weight percent on a dry weight basis.

[0290] The aerosol-generating film may further comprise carboxymethylcellulose, preferably sodium carboxymethylcellulose.

[0291] The aerosol-generating film may have a carboxymethylcellulose content of from 1 weight percent to 15 weight percent, or from 2 weight percent to 12 weight percent, or from 4 weight percent to 10 weight percent, on a dry weight basis.

[0292] Preferably, the aerosol-generating film comprises nicotine.

[0293] As used herein with respect to the present invention, the term "nicotine" is used to describe nicotine, nicotine base, or nicotine salts. In embodiments where the aerosol-generating film comprises nicotine base or nicotine salts, the amounts of nicotine recited herein are the amounts of free base nicotine or the amounts of protonated nicotine, respectively.

[0294] The aerosol-generating film may contain natural or synthetic nicotine.

[0295] The aerosol-generating film may include one or more monobasic nicotine salts.

[0296] As used herein in connection with the present invention, the term "monobasic nicotine salt" is used to describe a nicotine salt of a monobasic acid.

[0297] Preferably, the aerosol-generating film contains at least 0.5 weight percent nicotine on a dry weight basis. More preferably, the aerosol-generating film contains at least 1 weight percent nicotine on a dry weight basis. Even more preferably, the aerosol-generating film contains at least 2 weight percent nicotine on a dry weight basis. Additionally or alternatively, the aerosol-generating film preferably contains less than 10 weight percent nicotine on a dry weight basis. More preferably, the aerosol-generating film contains less than 8 weight percent nicotine on a dry weight basis. More preferably, the aerosol-generating film contains less than 6 weight percent nicotine on a dry weight basis.

[0298] For example, the aerosol-generating film may contain, on a dry weight basis, 0.5 to 10 weight percent nicotine, or 1 to 8 weight percent nicotine, or 2 to 6 weight percent nicotine.

[0299] The aerosol-generating film may be a substantially tobacco-free aerosol-generating film.

[0300] In a preferred embodiment, the aerosol-generating film comprises an acid. More preferably, the aerosol-generating film comprises one or more organic acids. Even more preferably, the aerosol-generating film comprises one or more carboxylic acids. In a particularly preferred embodiment, the acid is lactic acid, benzoic acid, fumaric acid, or levulinic acid.

[0301] Preferably, the aerosol-generating film comprises, on a dry weight basis, 0.25 to 3.5 weight percent acid, or 0.5 to 3 weight percent acid, or 1 to 2.5 weight percent acid.

[0302] The aerosol-generating film may have a thickness of about 0.1 millimeter to about 1 millimeter, more preferably about 0.1 millimeter to about 0.75 millimeter, more preferably about 0.1 millimeter to about 0.5 millimeter. In particularly preferred embodiments, a layer of the film-forming composition is formed having a thickness of about 50 micrometers to 400 micrometers, more preferably about 100 micrometers to 200 micrometers.

[0303] The aerosol-generating film may optionally be provided on a suitable carrier element.

[0304] The aerosol-forming substrate may comprise a gel composition comprising nicotine, at least one gelling agent and an aerosol former. Preferably, the gel composition is substantially free of tobacco.

[0305] The preferred weight ranges of nicotine in the gel composition are the same as those defined above in connection with the aerosol-generating film.

[0306] The gel composition preferably comprises at least 50 weight percent aerosol former, more preferably at least 60 weight percent aerosol former, and more preferably at least 70 weight percent aerosol former, on a dry weight basis. The gel composition may comprise up to 80 weight percent aerosol former. The aerosol former in the gel composition is preferably glycerol.

[0307] The gel composition preferably includes at least one gelling agent in a total amount ranging from about 0.4 weight percent to about 10 weight percent, or from about 0.5 weight percent to about 8 weight percent, or from about 1 weight percent to about 6 weight percent, or from about 2 weight percent to about 4 weight percent, or from about 2 weight percent to about 3 weight percent.

[0308] The term "gelling agent" refers to a compound that, when homogeneously added in an amount of about 0.3 weight percent to a 50 weight percent water / 50 weight percent glycerol mixture, forms a solid medium or support matrix leading to a gel. Gelling agents include, but are not limited to, hydrogen-bond cross-linking gelling agents and ionic cross-linking gelling agents.

[0309] The term "hydrogen-bond cross-linking gelator" refers to a gelator that forms non-covalent or physical cross-links via hydrogen bonds.

[0310] The hydrogen-bond cross-linking gelling agent may comprise one or more of galactomannan, gelatin, agarose, or konjac gum, or agar. Preferably, the hydrogen-bond cross-linking gelling agent comprises agar.

[0311] The term "ionically cross-linking gelator" refers to a gelator that forms non-covalent or physical cross-links through ionic bonds.

[0312] The ionic cross-linking gelling agent may include low acyl gellan, pectin, kappa carrageenan, iota carrageenan or alginate. Preferably, the ionic cross-linking gelling agent may include low acyl gellan.

[0313] The gelling agent may comprise one or more biopolymers, which may be formed from polysaccharides.

[0314] Examples of biopolymers include gellan gum (natural gellan gum, low acyl gellan gum, high acyl gellan gum, and low acyl gellan gum are preferred), xanthan gum, alginate (alginic acid), agar, and guar gum. It may be preferable for the composition to include xanthan gum. The composition may include two biopolymers. The composition may include three biopolymers. The composition may include two biopolymers in substantially equal amounts by weight. The composition may include three biopolymers in substantially equal amounts by weight.

[0315] The gel composition may further comprise a thickening agent. The thickening agent in combination with the hydrogen-bond cross-linking gelling agent and the ionic cross-linking gelling agent surprisingly appears to support a solid medium and maintain the gel composition even when the gel composition contains high levels of glycerol.

[0316] The term "thickener" refers to a compound that, when uniformly added in an amount of 0.3 percent by weight to a 50 percent by weight water / 50 percent by weight glycerol mixture at 25°C, increases the viscosity without resulting in the formation of a gel, and causes the mixture to remain in a fluid state or to remain fluid.

[0317] The gel composition preferably comprises a thickener in the range of about 0.2 weight percent to about 5 weight percent, or about 0.5 weight percent to about 3 weight percent, or about 0.5 weight percent to about 2 weight percent, or about 1 weight percent to about 2 weight percent.

[0318] The thickening agent may comprise one or more of xanthan gum, carboxymethylcellulose, microcrystalline cellulose, methylcellulose, gum arabic, guar gum, lambda carrageenan, or starch. Preferably, the thickening agent may comprise xanthan gum.

[0319] The gel composition may further comprise a divalent cation. Preferably, the divalent cation comprises calcium ions, such as calcium lactate in solution. The divalent cation (e.g., calcium ions) may aid in gel formation in compositions that include a gelling agent, such as an ionically crosslinking gelling agent. Ionic effects may aid gel formation. The divalent cation may be present in the gel composition in a range of about 0.1 to about 1 weight percent, or about 0.5 weight percent.

[0320] The gel composition may further comprise an acid. The acid may comprise a carboxylic acid. The carboxylic acid may comprise a ketone group. Preferably, the carboxylic acid may comprise a ketone group having less than about 10 carbon atoms, such as levulinic acid or lactic acid, or less than about 6 carbon atoms, or less than about 4 carbon atoms. Preferably, the carboxylic acid has three carbon atoms (such as lactic acid).

[0321] The gel composition preferably contains some water, as the gel composition is more stable if the composition contains some water.

[0322] Preferably, the gel composition comprises about 8 weight percent to about 32 weight percent water, or about 15 weight percent to about 25 weight percent water, or about 18 weight percent to about 22 weight percent water, or about 20 weight percent water.

[0323] Preferably, when a gel composition is used, the aerosol-forming substrate comprises a porous medium filled with the gel composition. The advantage of a porous medium loaded with a gel composition is that the gel composition is retained within the porous medium, which may aid in the manufacture, storage, or transportation of the gel composition. This may help maintain the desired shape of the gel composition, particularly during manufacture, transportation, or use.

[0324] The term "porous" is used herein to refer to a material that provides a plurality of pores or openings that allow the passage of air through the material.

[0325] The porous medium may be any suitable porous material capable of holding or retaining the gel composition. Ideally, the porous medium allows the gel composition to move within. In certain embodiments, the porous medium comprises natural, synthetic, or semi-synthetic materials, or a combination thereof. In certain embodiments, the porous medium comprises a sheet material, a foam, or a fiber, e.g., loose fiber, or a combination thereof. In certain embodiments, the porous medium comprises a woven fabric, a nonwoven fabric, or an extruded material, or a combination thereof. Preferably, the porous medium comprises cotton, paper, viscose, PLA, or cellulose acetate, or a combination thereof. Preferably, the porous medium comprises a sheet material, e.g., cotton or cellulose acetate. In a particularly preferred embodiment, the porous medium comprises a sheet made from cotton fibers.

[0326] The porous media may be crimped or chopped. The porous media may be in the form of sheets, threads, or tubular elements.

[0327] The aerosol-forming substrate may comprise nicotine. The nicotine-containing aerosol-forming substrate may be a nicotine salt matrix.

[0328] The aerosol-forming substrate preferably comprises a plant material and an aerosol former, the plant material preferably being an alkaloid-containing plant material, more preferably being a nicotine-containing plant material, and more preferably being a tobacco-containing material.

[0329] Preferably, the aerosol-forming substrate comprises at least 70 weight percent plant material on a dry weight basis, more preferably at least 90 weight percent plant material. Preferably, the aerosol-forming substrate comprises less than 95 weight percent plant material on a dry weight basis, such as 90-95 weight percent plant material on a dry weight basis.

[0330] The aerosol-forming substrate preferably comprises at least 5 weight percent aerosol formers on a dry weight basis, more preferably at least 10 weight percent aerosol formers. Preferably, the aerosol-forming substrate comprises less than 30 weight percent aerosol formers on a dry weight basis, such as 5 to 30 weight percent aerosol formers on a dry weight basis.

[0331] In some particularly preferred embodiments, the aerosol-forming substrate comprises a plant material and an aerosol former, the substrate having an aerosol former content of 5-30% by weight on a dry weight basis. The plant material is preferably an alkaloid-containing plant material, more preferably a nicotine-containing plant material, and more preferably a tobacco-containing material. Alkaloids are a class of naturally occurring nitrogen-containing organic compounds. Alkaloids are primarily found in plants, but are also found in bacteria, fungi, and animals. Examples of alkaloids include, but are not limited to, caffeine, nicotine, theobromine, atropine, and tubocurarine. A preferred alkaloid is nicotine, which may be found in tobacco.

[0332] The aerosol-forming substrate may comprise nicotine. The aerosol-forming substrate may comprise tobacco, for example, a tobacco-containing material containing volatile tobacco flavor compounds that are released from the aerosol-forming substrate upon heating. In a preferred embodiment, the aerosol-forming substrate may comprise a homogenized tobacco material, for example, cast leaf tobacco. The aerosol-forming substrate may comprise both solid and liquid components. The aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavor compounds that are released from the substrate upon heating. The aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may further comprise an aerosol former. Examples of suitable aerosol formers are glycerin and propylene glycol.

[0333] As used herein, the term "tobacco material" is used to describe any material containing tobacco, including, but not limited to, tobacco leaf, tobacco veins, tobacco stems, tobacco stems, tobacco dust, expanded tobacco, reconstituted tobacco material, and homogenized tobacco material.

[0334] As used herein, the term "homogenized tobacco" refers to a material formed by agglomerating particulate tobacco. Homogenized tobacco may include reconstituted tobacco or cast leaf tobacco, or a mixture of both. The term "reconstituted tobacco" refers to a paper-like material that can be made from tobacco by-products such as tobacco fines, tobacco dust, tobacco stems, or a mixture of the foregoing. Reconstituted tobacco can be made by extracting soluble chemicals in the tobacco by-product, processing the remaining tobacco fibers into a sheet, and then reapplying the extracted material in a concentrated form onto the sheet.

[0335] The term "cast leaf" is used herein to refer to a sheet product made by a casting process based on casting a slurry containing plant particles (e.g., clove particles, or tobacco particles and clove particles in a mixture) and a binder (e.g., guar gum) onto a support surface such as a belt conveyor, drying the slurry, and removing the dried sheet from the support surface. An example of a casting or cast leaf process is described, for example, in U.S. Pat. No. 5,724,998, for the production of cast leaf tobacco. In the cast leaf process, particulate plant material is mixed with liquid components (typically water) to form a slurry. Other added components in the slurry may include fibers, binders, and aerosol formers. The particulate plant material may be agglomerated in the presence of a binder. The slurry is cast onto a support surface and dried to form a sheet of homogenized plant material.

[0336] As used herein, the term "flavoring agent" refers to a composition having organoleptic properties that provide a sensory experience to the user, for example, to enhance the flavor of the aerosol. Flavoring agents can be used, for example, to deliver a taste (taste), an odor (smell), or both taste and odor to the user upon inhaling the aerosol.

[0337] As used herein, the term "aerosol-generating article" refers to an article comprising an aerosol-forming substrate capable of emitting a volatile compound capable of forming an aerosol. The aerosol-generating article may be disposable. An aerosol-generating article comprising an aerosol-forming substrate containing tobacco may be referred to herein as a tobacco stick.

[0338] As used herein, the term "aerosol-generating device" refers to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-generating device may interact with one or both of an aerosol-generating article including the aerosol-forming substrate and a cartridge including the aerosol-forming substrate. In some examples, the aerosol-generating device may heat the aerosol-forming substrate to facilitate the release of volatile compounds from the substrate. An electrically operated aerosol-generating device may include an atomizer, such as an electric heater, for heating the aerosol-forming substrate to form an aerosol.

[0339] As used herein, the term "aerosol-generating system" refers to the combination of an aerosol-generating device with an aerosol-forming substrate. When the aerosol-forming substrate forms part of an aerosol-generating article, the aerosol-generating system refers to the combination of an aerosol-generating device with an aerosol-generating article. In an aerosol-generating system, the aerosol-forming substrate and the aerosol-generating device work together to generate an aerosol.

[0340] As used herein, the term "tubular element" is used to mean an elongated element that defines a lumen or airflow passage along its longitudinal axis. Specifically, the term "tubular" is used herein to encompass any tubular element that has a substantially cylindrical cross-section and defines at least one airflow passage that establishes uninterrupted fluid communication between the upstream end of the tubular element and the downstream end of the tubular element. However, it will be appreciated that alternative geometric shapes for the tubular element may be possible.

[0341] As used herein, the terms "upstream" and "forward," as well as "downstream" and "rearward," are used to describe the relative positions of components or portions of components of an aerosol-generating article with respect to the direction of air flow through the aerosol-generating article during use. An aerosol-generating article according to the present invention has a proximal end from which aerosol exits the article during use. The proximal end of an aerosol-generating article may also be referred to as the mouth end or downstream end. The mouth end is downstream of the distal end. The distal end of an aerosol-generating article may also be referred to as the upstream end. Components or portions of components of an aerosol-generating article may be described as being upstream or downstream of one another based on their relative positions between the proximal end of the aerosol-generating article and the distal end of the aerosol-generating article. The forward side of a component or portion of a component of an aerosol-generating article is the portion at the end closest to the upstream end of the aerosol-generating article. The rearward side of a component or portion of a component of an aerosol-generating article is the portion at the end closest to the downstream end of the aerosol-generating article.

[0342] As used herein, the term "longitudinal" refers to a direction corresponding to the major longitudinal axis of the aerosol-generating article extending between the upstream and downstream ends of the aerosol-generating article.

[0343] The term "length" refers to the dimension of a component of an aerosol-generating article in the longitudinal direction. For example, it may be used to refer to the dimension of a rod or elongated tubular element in the longitudinal direction.

[0344] As used herein in connection with the present invention, the term "transverse" is used to describe a direction perpendicular to the longitudinal axis. Unless otherwise specified, a "cross section" of an aerosol-generating article or a component of an aerosol-generating article refers to a cross section.

[0345] As used herein, the term "proximal" refers to the user or mouth end of the aerosol-generating article, and the term "distal" refers to the end opposite the proximal end.

[0346] Components of an aerosol-generating article according to the present invention may be described as being upstream or downstream of one another based on their relative location between the proximal end of the aerosol-generating article and the distal end of the aerosol-generating article.

[0347] The aerosol-generating article comprises one or more susceptor elements contained within the aerosol-forming substrate portion. For example, one or more elongated susceptor elements may be disposed substantially longitudinally within the aerosol-forming substrate portion and in thermal contact with the aerosol-forming substrate.

[0348] As used herein, the term "susceptor" or "susceptor element" refers to an element that heats when subjected to an alternating magnetic field. This may be the result of eddy currents induced in the susceptor element, hysteresis losses, or both eddy currents and hysteresis losses. During use, the susceptor element is positioned in thermal contact or thermal proximity with an aerosol-forming substrate received in an aerosol-generating device or cartridge. In this manner, the aerosol-forming substrate is heated by the susceptor, thereby forming an aerosol.

[0349] The susceptor element may be formed from any material that can be inductively heated to a temperature sufficient to generate an aerosol from the aerosol-forming substrate. Preferred susceptor elements comprise metal or carbon.

[0350] Preferred susceptor elements may include or consist of a ferromagnetic material, such as a ferromagnetic alloy, ferritic iron, or ferromagnetic steel or stainless steel, etc. Suitable susceptor elements may be or include aluminum.

[0351] Suitable susceptor elements may include a non-metallic core having a metal layer, such as a metal band formed on the surface of the ceramic core. The susceptor element may have a protective outer layer, such as a protective ceramic or glass layer, encapsulating the susceptor element. The susceptor element may include a protective coating formed of glass, ceramic, or an inert metal formed over a core of susceptor element material.

[0352] The susceptor element may be disposed in thermal contact with the aerosol-forming substrate of the aerosol-forming substrate portion in which the susceptor element is incorporated. Thus, as the temperature of the susceptor element increases, the aerosol-forming substrate is heated and an aerosol is formed. Preferably, the susceptor element is disposed in direct physical contact with the aerosol-forming substrate, for example, within the aerosol-forming substrate.

[0353] An aerosol-generating device suitable for use with the aerosol-generating articles described herein may comprise a heating chamber for receiving at least a portion of the aerosol-generating article, and a heater for heating the aerosol-forming substrate portion of the aerosol-generating article when the aerosol-generating article is received in the heating chamber.

[0354] The aerosol generating device has a distal end and an oral end. The aerosol generating device may comprise a body or housing. The body or housing of the aerosol generating device may define a device cavity for removably receiving an aerosol-generating article at the oral end of the device.

[0355] The device cavity may be referred to as the heating chamber of the aerosol-generating device. The device cavity may extend between a distal end and an oral (or proximal) end. The distal end of the device cavity may be a closed end, and the oral (or proximal) end of the device cavity may be an open end. The aerosol-generating article may be inserted into the device cavity or heating chamber through the open end of the device cavity. The device cavity may be cylindrical in shape to fit the same shape of the aerosol-generating article.

[0356] The phrase "received within" may refer to the fact that a component or element is completely or partially received within another component or element. For example, the phrase "an aerosol-generating article is received within a device cavity" refers to the aerosol-generating article being completely or partially received within a cavity of an aerosol-generating device. When the aerosol-generating article is received within the device cavity, the aerosol-generating article may abut the distal end of the device cavity. When the aerosol-generating article is received within the device cavity, the aerosol-generating article may be substantially proximate to the distal end of the device cavity. The distal end of the device cavity may be defined by an end wall.

[0357] The length of the device cavity may be between 15 millimeters and 80 millimeters, or between 20 millimeters and 70 millimeters, or between 25 millimeters and 60 millimeters, or between 25 millimeters and 50 millimeters.

[0358] The length of the device cavity (or heating chamber) may be the same as or longer than the length of the aerosol-forming substrate portion. The length of the device cavity may be the same as or longer than the combined length of the upstream section or element and the aerosol-forming substrate portion. The length of the device cavity is preferably such that, when an aerosol-generating article is received with an aerosol-generating device, at least 75 percent of the length of the aerosol-forming substrate portion is inserted or received within the device cavity. More preferably, the length of the device cavity is such that, when an aerosol-generating article is received with an aerosol-generating device, at least 80 percent of the length of the aerosol-forming substrate portion is inserted or received within the device cavity. More preferably, the length of the device cavity is such that, when an aerosol-generating article is received with an aerosol-generating device, at least 90 percent of the length of the aerosol-forming substrate portion is inserted or received within the device cavity. This maximizes the length of the aerosol-forming substrate portion along which the aerosol-forming substrate can be heated during use, thereby optimizing aerosol generation from the aerosol-forming substrate and reducing tobacco waste.

[0359] The length of the device cavity may be such that when an aerosol-generating article is received in the device cavity, the downstream section, or a portion thereof, protrudes from the device cavity. The length of the device cavity may be such that when an aerosol-generating article is received in the device cavity, a portion of the downstream section (such as a hollow tubular cooling element or a downstream filter segment) protrudes from the device cavity. The length of the device cavity may be such that when an aerosol-generating article is received in the device cavity, a portion of the downstream section (such as a hollow tubular cooling element or a downstream filter segment) is received within the device cavity.

[0360] At least 25 percent of the length of the downstream section may be inserted or received within the device cavity when the aerosol-generating article is received within the device. At least 30 percent of the length of the downstream section may be inserted or received within the device cavity when the aerosol-generating article is received within the device.

[0361] The diameter of the device cavity may be between 4 mm and 10 mm. The diameter of the device cavity may be between 5 mm and 9 mm. The diameter of the device cavity may be between 6 mm and 8 mm. The diameter of the device cavity may be between 6 mm and 7 mm.

[0362] The diameter of the device cavity may be substantially the same as or larger than the diameter of the aerosol-generating article, and may be the same as the diameter of the aerosol-generating article to establish a tight fit therewith.

[0363] The device cavity may be configured to establish a tight fit with an aerosol-generating article received within the device cavity. A tight fit may refer to a slip fit. The aerosol-generating device may include a peripheral wall. Such a peripheral wall may define the device cavity or a heating chamber. The peripheral wall defining the device cavity may be configured to engage in a tight fit with an aerosol-generating article received within the device cavity such that, when received within the device, there is substantially no gap or empty space between the peripheral wall defining the device cavity and the aerosol-generating article.

[0364] Such an airtight fit may establish an airtight fit or configuration between the device cavity and the aerosol-generating article received therein.

[0365] In such an airtight configuration, there are substantially no gaps or empty spaces between the peripheral walls defining the device cavity and the aerosol-generating article for air to flow through.

[0366] A tight fit with the aerosol-generating article may be established along the entire length of the device cavity or along a portion of the length of the device cavity.

[0367] The aerosol generating device may include an airflow channeling extending between the channel inlet and the channel outlet. The airflow channel may be configured to establish fluid communication between the interior of the device cavity and the exterior of the aerosol generating device. The airflow channel of the aerosol generating device may be defined within the housing of the aerosol generating device to enable fluid communication between the interior of the device cavity and the exterior of the aerosol generating device. When an aerosol-generating article is received within the device cavity, the airflow channel may be configured to provide air flow into the article to deliver the generated aerosol to a user who inhales through the mouth end of the article.

[0368] The airflow channel of the aerosol generating device may be defined within or by the peripheral wall of the housing of the aerosol generating device. In other words, the airflow channel of the aerosol generating device may be defined within the thickness of the peripheral wall, or by the inner surface of the peripheral wall, or a combination of both. The airflow channel may be partially defined by the inner surface of the peripheral wall, or partially defined within the thickness of the peripheral wall. The inner surface of the peripheral wall defines the periphery of the device cavity.

[0369] The airflow channel of the aerosol generating device may extend from an inlet located at the oral or proximal end of the aerosol generating device to an outlet located away from the oral end of the device. The airflow channel may extend along a direction parallel to the longitudinal axis of the aerosol generating device.

[0370] The heater may be of any suitable type, although in the present invention it is preferred that the heater is an external heater.

[0371] The heater is preferably located in or around the heating chamber.

[0372] Preferably, the heater externally heats the aerosol-forming substrate portion when the aerosol-generating article is received within the aerosol-generating device. Such an external heater may surround the aerosol-generating article when inserted or received within the aerosol-generating device.

[0373] In some embodiments, the heater is arranged to heat the outer surface of the aerosol-forming substrate portion.

[0374] In some embodiments, the heater is arranged to be inserted into the aerosol-forming substrate when the aerosol-forming substrate is received within the cavity.

[0375] The heater may be located within the device cavity or heating chamber.

[0376] The heater may include at least one heating element. The at least one heating element may be any suitable type of heating element. In some embodiments, the device includes only one heating element. In some embodiments, the device includes multiple heating elements.

[0377] Suitable materials for forming the at least one resistive heating element include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilicide), carbon, graphite, metals, metal alloys, and composites made of ceramic and metallic materials. Such composites may include doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, and platinum group metals. Examples of suitable metal alloys include stainless steel, nickel-, cobalt-, chromium-, aluminum-, titanium-, zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese-, and iron-containing alloys, as well as nickel-, iron-, cobalt-, and stainless steel-based superalloys, Timetal®, and iron-manganese-aluminum-based alloys.

[0378] In some embodiments, the at least one resistive heating element comprises one or more stamped sections of an electrically resistive material (such as stainless steel), or alternatively, the at least one resistive heating element may comprise a heating wire or filament (e.g., Ni-Cr (nickel-chromium), platinum, tungsten, or alloy wire).

[0379] In some embodiments, the at least one heating element comprises an electrically insulating substrate and the at least one resistive heating element is provided on the electrically insulating substrate.

[0380] The electrically insulating substrate may comprise any suitable material. For example, the electrically insulating substrate may comprise one or more of paper, glass, ceramic, anodized metal, coated metal, and polyimide. The ceramic may comprise mica, alumina (Al2O3), or zirconia (ZrO2). Preferably, the electrically insulating substrate has a thermal conductivity of about 40 watts per meter Kelvin or less, preferably about 20 watts per meter Kelvin or less, and ideally about 2 watts per meter Kelvin or less.

[0381] The heater may comprise a heating element comprising a rigid, electrically insulating substrate having one or more conductive tracks or wires arranged on its surface. Depending on the size and shape of the electrically insulating substrate, it may be possible to insert the heater directly into the aerosol-forming substrate. If the electrically insulating substrate is not sufficiently rigid, the heating element may comprise additional reinforcing means. An electric current may be passed through one or more conductive tracks to heat the heating element and the aerosol-forming substrate.

[0382] In some embodiments, the heater comprises an induction heating arrangement. The induction heating device may comprise an inductor coil and a power source configured to provide a high-frequency oscillating current to the inductor coil. As used herein, high-frequency oscillating current means an oscillating current having a frequency between about 500 kHz and about 30 MHz. The heater may advantageously comprise a DC / AC inverter for converting DC current provided by a DC power source into alternating current. The inductor coil may be arranged to generate a high-frequency oscillating electromagnetic field upon receiving the high-frequency oscillating current from the power source. The inductor coil may be arranged to generate a high-frequency oscillating electromagnetic field within the device cavity. In some embodiments, the inductor coil may substantially surround the device cavity. The inductor coil may extend at least partially along the length of the device cavity.

[0383] The heater may include an induction heating element. The induction heating element may be a susceptor element. The susceptor element may be arranged so that when an aerosol-generating article is received within the cavity of the aerosol-generating device, an oscillating electromagnetic field generated by the inductor coil induces a current in the susceptor element, heating the susceptor element. In these embodiments, the aerosol-generating device is preferably capable of generating a fluctuating electromagnetic field having a magnetic field strength (H-field strength) of 1 to 5 kiloamperes per meter (kA / m), preferably 2 to 3 kA / m, e.g., about 2.5 kA / m. Electrically operated aerosol generators are preferably capable of generating a fluctuating electromagnetic field having a frequency of 1 to 30 MHz, e.g., 1 to 10 MHz, e.g., 5 to 7 MHz.

[0384] In these embodiments, the susceptor element is preferably positioned in contact with the aerosol-forming substrate. In some embodiments, the susceptor element is positioned within the aerosol-generating device. In these embodiments, the susceptor element may be positioned within a cavity. The aerosol-generating device may include only one susceptor element. The aerosol-generating device may include multiple susceptor elements. In some embodiments, the susceptor element is preferably arranged to heat the outer surface of the aerosol-forming substrate.

[0385] The susceptor element may comprise any suitable material as described above in connection with the susceptor element incorporated within the aerosol-forming substrate portion.

[0386] In some embodiments, the aerosol generating device may comprise at least one resistive heating element and at least one inductive heating element, hi some embodiments, the aerosol generating device may comprise a combination of resistive and inductive heating elements.

[0387] In use, the heater can be controlled to operate within a defined operating temperature range that is less than the maximum operating temperature. The operating temperature range within the heating chamber (or device cavity) is preferably from about 150 degrees Celsius to about 300 degrees Celsius. The operating temperature range of the heater may be from about 150 degrees Celsius to about 250 degrees Celsius.

[0388] The aerosol generating device may include a power source. The power source may be a DC power source. In some embodiments, the power source is a battery. The power source may be a nickel-metal hydride battery, a nickel-cadmium battery, or a lithium-based battery (e.g., a lithium-cobalt, lithium iron phosphate, or lithium polymer battery). However, in some embodiments, the power source may be another form of charge storage device, such as a capacitor. The power source may require recharging and may have a capacity that allows for the storage of sufficient energy for one or more user operations, such as one or more aerosol generation experiences. [Brief explanation of the drawings]

[0389] [Figure 1] (a) and (b) show an aerosol-generating article. [Figure 2] (a) to (c) show aerosol-generating articles. [Figure 3] (a) and (b) show an aerosol-generating article. [Figure 4] (a) and (b) show an aerosol-generating article. DETAILED DESCRIPTION OF THE INVENTION

[0390] The following provides a non-exhaustive list of non-limiting examples, any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0391] Example 1: An aerosol-generating article comprising: a central axis extending centrally along the longitudinal direction of the aerosol-generating article; an aerosol-forming substrate portion containing a susceptor and an aerosol-forming substrate at least partially surrounding the susceptor; a substrate wrapper at least partially surrounding the aerosol-forming substrate portion and defining an overlap region of the overlapping end portion of the substrate wrapper; the substrate wrapper has a thickness of 50 micrometers or greater; the substrate wrapper includes one or more layers having the same length in a direction parallel to the central axis; The susceptor is a first straight line perpendicular to the flat, planar surface of the flat, planar susceptor portion; The angle between the central axis and a second line perpendicular to the central axis and extending from the central axis to a position within the overlap region is An aerosol-generating article comprising a flat, planar susceptor portion oriented at an angle between 0 degrees and 25 degrees.

[0392] Example 2: An aerosol-generating article as described in example 1, wherein all combinations of one or more layers of the substrate wrapper having the same length define a total thickness of the substrate wrapper of 50 micrometers or more.

[0393] Example 3: An aerosol-generating article according to Example 1 or Example 2, wherein at least one of the one or more layers of the substrate wrapper has an individual thickness of 50 micrometers or greater.

[0394] Example 4: An aerosol-generating article as described in Example 3, wherein each of the one or more layers of the substrate wrapper having the same length has an individual thickness of 50 micrometers or more.

[0395] Example 5: An aerosol-generating article according to any one of Examples 1 to 4, wherein the substrate wrapper does not extend in the longitudinal direction of the aerosol-generating article beyond the longitudinal ends of the aerosol-forming substrate portion.

[0396] Example 6: An aerosol-generating article comprising: a central axis extending centrally along the longitudinal direction of the aerosol-generating article; an aerosol-forming substrate portion containing a susceptor and an aerosol-forming substrate at least partially surrounding the susceptor; a substrate wrapper at least partially surrounding the aerosol-forming substrate portion and defining an overlap region of the overlapping end portion of the substrate wrapper; the substrate wrapper has a thickness of 50 micrometers or greater; the substrate wrapper does not extend beyond the ends of the aerosol-forming substrate portion in a direction parallel to the central axis; The susceptor is a first straight line perpendicular to the flat, planar surface of the flat, planar susceptor portion; The angle between the central axis and a second line perpendicular to the central axis and extending from the central axis to a position within the overlap region is An aerosol-generating article comprising a flat, planar susceptor portion oriented at an angle between 0 degrees and 25 degrees.

[0397] Example 7: 7. An aerosol-generating article according to any one of Examples 1 to 6, wherein the substrate wrapper has a thickness of 60 micrometers or more, preferably 70 micrometers or more, more preferably 75 micrometers or more, more preferably 90 micrometers or more, more preferably 120 micrometers or more, more preferably 145 micrometers or more.

[0398] Example 8: The aerosol-generating article of example 7, wherein the substrate wrapper has a thickness of 140 micrometers to 160 micrometers.

[0399] Example 9: 9. An aerosol-generating article according to any one of Examples 1 to 8, wherein the ratio of the thickness of the substrate wrapper to the diameter of the aerosol-forming substrate portion is within the range of about 1:120 to about 1:20, or about 1:100 to about 1:30, or about 1:80 to about 1:35, or about 1:60 to about 1:40.

[0400] Example 10: 10. An aerosol-generating article according to any one of Examples 1 to 9, wherein the density of the substrate wrapper is 800 kilograms per cubic meter or less, preferably 750 kilograms per cubic meter or less, more preferably 700 kilograms per cubic meter or less, more preferably 650 kilograms per cubic meter or less, more preferably 600 kilograms per cubic meter or less, more preferably 550 kilograms per cubic meter or less, more preferably 500 kilograms per cubic meter or less, more preferably 450 kilograms per cubic meter or less, more preferably 400 kilograms per cubic meter or less, more preferably 350 kilograms per cubic meter or less, more preferably about 320 kilograms per cubic meter.

[0401] Example 11: An aerosol-generating article according to any one of Examples 1 to 10, wherein the substrate wrapper has a basis weight of less than 60 grams per square meter.

[0402] Example 12: 12. The aerosol-generating article of claim 11, wherein the substrate wrapper has a basis weight of greater than 28 grams per square meter and less than 50 grams per square meter.

[0403] Example 13: An aerosol-generating article according to any one of Examples 1 to 12, wherein the substrate wrapper has a thickness greater than 145 micrometers and a density of 400 kilograms per cubic meter or less.

[0404] Example 14: An aerosol-generating article according to any one of Examples 1 to 13, wherein the substrate wrapper is perforated.

[0405] Example 15: An aerosol-generating article according to any one of Examples 1 to 14, wherein the substrate wrapper is embossed.

[0406] Example 16: An aerosol-generating article described in any of Examples 1 to 13, wherein the substrate wrapper has a uniform thickness that does not vary at any point by more than about 30 micrometers, or more than about 20 micrometers, or more than about 10 micrometers, or more than about 5 micrometers.

[0407] Example 17: 17. An aerosol-generating article according to any one of Examples 1 to 16, wherein the substrate wrapper exhibits a wrapper permeability in the range of 4000 Coresta units to 4800 Coresta units, preferably 4200 Coresta units to 4600 Coresta units, more preferably 4300 Coresta units to 4500 Coresta units, the cigarette paper permeability being determined utilising international standard test method ISO 2965:2009, the results being presented as cubic centimetres per minute per square centimetre, referred to as "Colesta Units".

[0408] Example 18: 18. An aerosol-generating article according to any one of Examples 1 to 17, wherein the substrate wrapper has a roughness of from about 50 Bekk seconds to about 1000 Bekk seconds, preferably from about 100 Bekk seconds to about 200 Bekk seconds.

[0409] Example 19: An aerosol-generating article according to any one of Examples 1 to 18, wherein the substrate wrapper extends along the entire length of the aerosol-forming substrate portion in a direction parallel to the longitudinal axis of the aerosol-generating article.

[0410] Example 20: 20. The aerosol-generating article of any one of Examples 1-19, wherein the substrate wrapper comprises one or more of cardboard, plastic, and metal foil.

[0411] Example 21: 21. The aerosol-generating article of any one of Examples 1 to 20, wherein the substrate wrapper comprises one or more of a cellulosic material, such as paper, wood, textiles, natural fibers, and man-made fibers.

[0412] Example 22: 22. The aerosol-generating article of any one of Examples 1 to 21, wherein the substrate wrapper comprises a paper layer.

[0413] Example 23: 23. An aerosol-generating article according to any one of Examples 1 to 22, wherein the substrate wrapper comprises a laminate sheet, preferably the substrate wrapper is made of a laminate sheet, more preferably the laminate sheet is a laminate of a paper layer with an aluminum layer.

[0414] Example 24: An aerosol-generating article according to any one of Examples 1 to 23, wherein the substrate wrapper is formed from a single continuous sheet, preferably a single paper sheet.

[0415] Example 25: An aerosol-generating article described in any of Examples 1 to 23, wherein the substrate wrapper is a substrate wrapper system formed from a first individual wrapper sheet and a second individual wrapper sheet, the first individual wrapper sheet including a first overlap region formed by overlapping opposing end portions of the first individual wrapper sheet, the second individual wrapper sheet including a second overlap region formed by overlapping opposing end portions of the second individual wrapper sheet, and the first and second overlap regions are provided on opposite sides of a first flat, planar susceptor portion.

[0416] Example 26: An aerosol-generating article according to any one of Examples 1 to 25, wherein the total length of the aerosol-forming substrate portion is 11 mm or less.

[0417] Example 27: An aerosol-generating article according to any one of Examples 1 to 26, wherein the aerosol-forming substrate is provided in the form of an assembly of sheets of homogenised tobacco material.

[0418] Example 28: 28. An aerosol-generating article as described in Example 27, wherein the sheet of homogenized tobacco material has a basis weight of less than 210 grams per square meter, preferably less than 200 grams per square meter, and more preferably about 192 grams per square meter.

[0419] Example 29: An aerosol-generating article according to Example 27 or Example 28, wherein the sheet of homogenized tobacco material has a thickness of greater than 215 micrometers, preferably greater than 220 micrometers, and more preferably about 228 micrometers.

[0420] Example 30: An aerosol-generating article described in any of Examples 27 to 29, wherein the sheet of homogenized tobacco material is a molded sheet, and the homogenized tobacco material comprises tobacco particles having an average particle size (D95) of more than 50 micrometers, preferably more than 50 micrometers but less than 100 micrometers, more preferably 60 micrometers to 80 micrometers, more preferably 65 micrometers to 75 micrometers, more preferably about 70 micrometers, prior to the molding process.

[0421] Example 31: 31. An aerosol-generating article according to any one of Examples 1 to 30, wherein the aerosol-forming substrate comprises tobacco material, about 1 percent to about 5 percent binder, and about 10 percent to about 30 percent glycerin, on a dry weight basis.

[0422] Example 32: 32. The aerosol-generating article of any one of Examples 1 to 31, wherein the aerosol-forming substrate portion defines a substantially cylindrical shape having a diameter in the range of about 6.8 millimeters to about 7.1 millimeters, or about 6.8 millimeters to about 7.0 millimeters.

[0423] Example 33: An aerosol-generating article according to any one of Examples 1 to 32, wherein the angle is 0 to 20 degrees, preferably 0 to 15 degrees, more preferably 0 to 10 degrees, and more preferably 0 to 5 degrees.

[0424] Example 34: An aerosol-generating article according to any one of Examples 1 to 33, wherein the overlap region extends along less than 15 percent, preferably less than 10 percent, and more preferably less than 5 percent of the perimeter of the aerosol-forming substrate portion.

[0425] Example 35: An aerosol-generating article according to any one of Examples 1 to 34, wherein the second straight line extends from the central axis to the center of the overlap region.

[0426] Example 36: An aerosol-generating article according to any one of Examples 1 to 35, wherein the second straight line extends from the central axis to a glue line provided within the overlap region.

[0427] Example 37: An aerosol-generating article according to any one of Examples 1 to 36, wherein the thickness of the substrate wrapper is measured in an area that is not an overlap area.

[0428] Example 38: An aerosol-generating article described in any of Examples 1 to 37, wherein the susceptor strips are elongated, flat, planar susceptor strips with central axes parallel to each other, the susceptor strips having a length of 5 millimeters to 15 millimeters and a width of at least about 1 millimeter, preferably at least about 2 millimeters.

[0429] Example 39: 39. The aerosol-generating article of any one of Examples 1 to 38, wherein the susceptor is centrally disposed within the aerosol-forming substrate portion.

[0430] Example 40: In a direction parallel to the central axis, the length of the overlapping region is equal to or greater than the length of the susceptor; An aerosol-generating article according to any one of Examples 1 to 39, wherein the width of the overlap region in a direction perpendicular to the central axis is equal to or smaller than the width of the susceptor.

[0431] Example 41: 41. The aerosol-generating article of any one of Examples 1 to 40, wherein the susceptor comprises a metallic material, preferably aluminum.

[0432] Example 42: A package comprising a plurality of aerosol-generating articles, each of which is an aerosol-generating article according to any one of Examples 1 to 41.

[0433] Example 42: An aerosol generating system comprising: an aerosol-generating article according to any one of Examples 1 to 41; and an aerosol generating device including a heating chamber configured to at least partially insert the aerosol-generating article into the heating chamber.

[0434] Features described with respect to one embodiment may be equally applied to other embodiments of the invention.

[0435] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which:

[0436] FIG. 1a shows an aerosol-generating article in cross section. The aerosol-generating article includes a mouth-end filter 10 located at the proximal end of the article. The article further includes a PLA (polylactic acid) plug 12, a hollow acetate tube 14, and an aerosol-forming substrate portion 16 including an aerosol-forming substrate, e.g., a collection of homogenized tobacco sheets. The article is surrounded by a tipping wrapper 18. A flat, planar susceptor 20 is disposed within and surrounded by the aerosol-forming substrate portion 16. A central axis 22 extends centrally along the longitudinal direction of the aerosol-generating article. The aerosol-forming substrate portion 16 is surrounded by a substrate wrapper 24. The substrate wrapper has a thickness of at least 50 micrometers. The substrate wrapper 24 does not extend beyond the longitudinal ends of the aerosol-forming substrate portion 16 in a direction parallel to the central axis 22.

[0437] Figure 1b shows a cross section of the article of Figure 1a taken along line XX shown in Figure 1a. Figure 1b shows that the substrate wrapper 24 forms an overlap region between overlapping opposing end portions of the substrate wrapper 24. The width of the overlap region is indicated by double-headed arrow 26. A glue line 28 may be present in the center of the overlap region.

[0438] A first line 30 is shown that is perpendicular to both of the opposing flat planar surfaces 21 of the flat planar susceptor 20. A second line 32 is shown that is perpendicular to the central axis 22 and extends from the central axis 22 to a location within the overlap region (in this case, the glue line 28 within the overlap region). The first line 30 and the second line 32 are substantially collinear, and the angle between the first line and the second line is approximately 0 degrees.

[0439] In the illustrated embodiment, the susceptor 20 is substantially centered with the aerosol-forming substrate portion 16. Therefore, the susceptor can substantially uniformly heat the surrounding aerosol-forming substrate during use. At the same time, the flat, planar susceptor 20 is oriented so that, while centered, it is positioned as far away from the glue line 28 as possible. This reduces unintentional heating of the glue. The susceptor is also positioned away from the pit 33. The pit 33 represents the area adjacent to the edge of the underlying end portion of the substrate wrapper 24 in the overlap region. In particular, if a thick substrate wrapper 24, e.g., thicker than 50 micrometers, is used, the thick edge of the underlying end portion of the substrate wrapper 24 will create a larger pit 33. In the pit 33, no or little aerosol-forming substrate is present because the pit is shielded by the edge of the inner wrapper layer. Because there is little or no aerosol-forming substrate present within the pit 33, there is little point in heating this area. As a result, when the susceptor 20 is located away from the pit 33, unnecessary heating of the pit 33 can be reduced, thereby resulting in an energy-efficient aerosol-generating article.

[0440] The flat, planar surface 21 is disposed substantially parallel to the overlap region. The substantially parallel aligned planar susceptor 20 can function as a stabilizing underlayer when the opposing end portions of the substrate wrapper 24 are pressed together to close the overlap region during the manufacture of an aerosol-generating article.

[0441] FIG. 2a shows a cross section of the article of FIG. 1a taken along line XX, also shown in FIG. 1a, except that tipping wrapper 18 and glue line 28 are absent.

[0442] The orientation of the flat planar susceptor 20 does not change, so the angle of the first straight line 30 does not change compared to FIG. 1b.

[0443] A second line 32 is defined perpendicular to the central axis 22 and extends from the central axis 22 to a location within the overlap region. Unlike Figure 1b, in Figure 2a the location within the overlap region is not exactly in the center of the overlap region. Instead, in Figure 2a, the second line 32 is depicted as extending from the central axis 22 to a peripheral location within the overlap region. As a result, there is an angle 34 of approximately 10 degrees between the first line 30 and the second line 32.

[0444] FIG. 2b shows an alternative embodiment that differs from the embodiment of FIG. 1b in that the flat planar susceptor 20 is somewhat offset from the central axis 22 and tilted by approximately 10 degrees. This may be due to, for example, manufacturing tolerances. As a result, a first line 30, which is perpendicular to both opposing flat planar surfaces 21, is also tilted by approximately 10 degrees compared to FIG. 1b. A second line 32 is defined as in FIG. 1b. Thus, there is an angle 34 of approximately 10 degrees between the first line 30 and the second line 32.

[0445] It should be noted that if a different configuration for second line 32 is used in the embodiment of Figure 2b, for example, if second line 32 extends to a peripheral portion of the overlap region as in Figure 2a, then in the embodiment of Figure 2b, angle 34 between first line 30 and second line 32 will result between about 20 degrees and about 0 degrees, depending on which of the two peripheral portions of the overlap region is selected. However, regardless of which configuration is selected for second line 32 in Figure 2b, angle 34 will always be less than 25 degrees.

[0446] FIG. 2c shows the orientation of a flat, planar susceptor 20 not in accordance with the present invention. The flat, planar susceptor 30 is tilted approximately 90 degrees compared to the embodiment of FIG. 1b. As a result, the first line 30 is also rotated approximately 90 degrees. The angle 34 between the first line 30 and the second line 32 is approximately 90 degrees. Note that if a different configuration for the second line 32 is used in the embodiment of FIG. 2c, for example, if the second line 32 extends to a peripheral portion of the overlap region as in FIG. 2a, the angle 34 between the first line 30 and the second line 32 in the embodiment of FIG. 2c would result in an angle 34 of approximately 80 degrees. Regardless of which configuration is selected for the second line 32 in FIG. 2c, the angle 34 is always approximately 80 to 90 degrees.

[0447] The double-headed arrow 36 in Figure 2c indicates that the susceptor 20 in the embodiment of Figure 2c is closer to the glue line 28 when compared to Figure 1b. Therefore, the embodiment of Figure 1b may reduce unintentional heating of the glue line when compared to the embodiment of Figure 2c. Furthermore, the susceptor 20 in the embodiment of Figure 2c is closer to the pit 33 when compared to Figure 1b. Therefore, the embodiment of Figure 1b may reduce unintentional heating of the pit 33 when compared to the embodiment of Figure 2c.

[0448] Figure 3a shows an aerosol-generating article in cross section. The article of Figure 3a comprises a mouth-end filter 10, a fine hollow acetate tube 38, a hollow acetate tube 40, an aerosol-forming substrate portion 16, and a front plug 42. The mouth-end filter 10, the fine hollow acetate tube 38, and the hollow acetate tube 40 form a downstream section downstream of the aerosol-forming substrate portion 16. The front plug 42 forms an upstream section upstream of the aerosol-forming substrate portion 16.

[0449] The aerosol-forming substrate portion 16 includes a flat, planar susceptor 20 surrounded by an aerosol-forming substrate. The aerosol-forming substrate portion 16 is surrounded by a thick substrate wrapper 24. The susceptor 20 is aligned with the overlapping region of the substrate wrapper 24, as shown in FIG. 1b.

[0450] The front plug 42 may be a filter plug. The distal portion of the article is surrounded by a tipping wrapper 18, and the proximal portion is surrounded by a mouthpiece wrapper 44. A row of circumferential vent holes 46 is provided in the area where the mouthpiece wrapper 44 overlaps the tipping wrapper 18. The vent holes 46 may be provided in one or both of the fine hollow acetate tubing 38, the mouthpiece wrapper 44, and the tipping wrapper 18.

[0451] The outer diameter of the article may be about 7 millimeters, preferably 7.1 millimeters. The overall length of the article may be about 45 millimeters. In one embodiment, the mouth-end filter 10 is about 12 millimeters long, the fine hollow acetate tubing 38 is about 9 millimeters long, the hollow acetate tubing 40 is about 8 millimeters long, the aerosol-forming substrate portion 16 is about 11 millimeters long, and the front plug 42 is about 5 millimeters long.

[0452] Figure 3b shows the aerosol-generating article in cross-section. The aerosol-generating article of Figure 3b may have an overall length of about 75 millimeters and an outer diameter of 6.7 millimeters.

[0453] The article of Figure 3b includes a hollow mouthpiece tube 48, e.g., a hollow cylindrical tube made of cellulose acetate, at the proximal end of the article. The hollow mouthpiece tube 48 defines an interior cavity extending entirely from the upstream end of the hollow mouthpiece tube 48 to the downstream end of the mouth-end filter 10. The interior cavity is substantially empty, thereby permitting substantially unrestricted airflow along the interior cavity. The hollow mouthpiece tube 48 does not substantially contribute to the overall RTD of the aerosol-generating article. The length of the hollow mouthpiece tube 48 may be approximately 6 millimeters, and the outer diameter may be approximately 6.7 millimeters. The wall thickness of the hollow mouthpiece tube 48 may be approximately 1 millimeter.

[0454] The article further comprises a mouth end filter 10. The mouth end filter 10 may have a length of about 10 millimeters. The outer diameter of the mouth end filter 10 may be about 6.7 millimeters.

[0455] The article further comprises a hollow tube 50, e.g., a cardboard tube. The hollow tube 50 does not substantially contribute to the overall RTD of the aerosol-generating article. More specifically, the RTD of the hollow tube 50 is about 0 millimeters of water. The hollow tube 50 may have a length of about 25 millimeters or more, an outer diameter of about 6.7 millimeters, and an inner diameter of about 6.2 millimeters. Accordingly, the peripheral wall thickness of the hollow tube 50 may be about 0.25 millimeters.

[0456] The hollow tube 50 may include one or more rows of vent holes 46 disposed circumferentially around the hollow tube 50 in a cross section substantially perpendicular to the longitudinal axis of the article. The ventilation level of the aerosol-generating article may be about 75 percent.

[0457] At the distal end, the article comprises an aerosol-forming substrate portion 16 comprising a flat, planar susceptor 20 surrounded by an aerosol-forming substrate. The aerosol-forming substrate portion 16 is surrounded by a thick substrate wrapper 24. The susceptor 20 is aligned with the overlapping region of the substrate wrapper 24, as shown in FIG. 1b. Additionally, one or more outer wrappers 18, 44 may be provided surrounding at least a portion of the aerosol-generating article. The one or more outer wrappers 18, 44 may also include a vent hole 46. If present, the outer wrapper 44 may overlie a portion of the outer wrapper 18 that overlies the hollow tube 50. In this manner, the outer wrapper 44 effectively bonds the mouth-end filter 10 to the remaining components of the article. The width of the outer wrapper 44 may be approximately 26 millimeters.

[0458] In one embodiment, the aerosol-generating article of Figure 3b has an overall length of about 80 millimeters and an outer diameter of about 6.5 millimeters, the hollow tube 50 has a length of about 25 millimeters or more, the oral-end filter 10 has a length of about 10 millimeters, and the hollow mouthpiece tube 48 is about 6 millimeters long.

[0459] Figure 4a shows in cross section an aerosol-generating article with an aerosol-forming substrate portion 16 at its distal end. The aerosol-forming substrate portion 16 includes a flat, planar susceptor 20 surrounded by an aerosol-forming substrate. The aerosol-forming substrate portion 16 is surrounded by a thick substrate wrapper 24. The susceptor 20 is aligned with the overlapping region of the substrate wrapper 24, as shown in Figure 1b.

[0460] The downstream section includes a hollow tube 50 and a mouth-end filter 10. The hollow tube 50 may include one or more rows of vent holes 46. The upstream section includes a front plug 42. The front plug 42 may be provided in the form of a cylindrical plug of cellulose acetate tow, or may be provided in the form of a hollow cylindrical plug of cellulose acetate tow having a wall thickness of about 1 millimeter.

[0461] The aerosol-generating article may have a total length of about 45 millimeters and an outer diameter of about 7.2 millimeters. The total length of the downstream section may be about 20 to 30 millimeters. The length of the mouth-end filter 10 may be about 7 millimeters. The total length of the upstream section may be about 5 millimeters.

[0462] Figure 4b shows in cross section an aerosol-generating article with an aerosol-forming substrate portion 16 including a flat, planar susceptor 20 surrounded by an aerosol-forming substrate. The aerosol-forming substrate portion 16 is surrounded by a thick substrate wrapper 24. The susceptor 20 is aligned with the overlapping region of the substrate wrapper 24 as shown in Figure lb. The downstream section includes a hollow tube 50 and a mouth-end filter 10. The hollow tube 50 may include one or more rows of vent holes 46.

[0463] The aerosol-generating article of FIG. 4b may have an overall length of approximately 45 millimeters and an outer diameter of 7.2 millimeters. The hollow tube 50 may have a length of approximately 20-30 millimeters, an outer diameter of approximately 7.2 millimeters, and an inner diameter of approximately 6.7 millimeters. Accordingly, the peripheral wall thickness of the hollow tube 50 is approximately 0.25 millimeters. The mouth-end filter 10 may have a length of approximately 5-7 millimeters and an outer diameter of approximately 7.2 millimeters. The mouth-end filter 10 may comprise a low-density cellulose acetate filter segment. The RTD of the mouth-end filter 10 may be approximately 8 millimeters of water column. The mouth-end filter 10 may be individually wrapped with a plug wrap (not shown). Additionally, one or more outer wrappers 18, 44 may be provided that surround at least a portion of the aerosol-generating article.

Claims

1. Aerosol-generating article, A central axis extending towards the center along the long axis of the aerosol generating article, an aerosol-forming substrate portion that contains a susceptor and an aerosol-forming substrate that at least partially surrounds the susceptor, The system comprises a substrate wrapper that at least partially surrounds the aerosol-forming substrate portion and forms an overlapping region at the overlapping end portion of the substrate wrapper, The substrate wrapper has a thickness of 50 micrometers or more. The substrate wrapper includes one or more layers having the same length in a direction parallel to the central axis, The susceptor, A first straight line perpendicular to the flat, planar surface of the flat, planar susceptor portion, The angle between the central axis and a second straight line that is perpendicular to the central axis and extends from the central axis to a position within the overlapping region is An aerosol generating article comprising a flat, planar susceptor portion oriented to an angle of 0 to 25 degrees, wherein pits are formed directly adjacent to the overlapping region, and the pits do not contain an aerosol-forming substrate.

2. The aerosol generating article according to claim 1, wherein the angle is 0 to 20 degrees, preferably 0 to 15 degrees, more preferably 0 to 10 degrees, and more preferably 0 to 5 degrees.

3. The aerosol generating article according to claim 1 or 2, wherein the substrate wrapper has a thickness of 60 micrometers or more, preferably 70 micrometers or more, more preferably 75 micrometers or more, more preferably 90 micrometers or more, more preferably 120 micrometers or more, and more preferably 145 micrometers or more.

4. The aerosol generating article according to claim 3, wherein the substrate wrapper has a thickness of 140 micrometers to 160 micrometers.

5. The aerosol generating article according to claim 1, wherein the ratio of the thickness of the substrate wrapper to the diameter of the aerosol-forming substrate portion is within the range of approximately 1:120 to approximately 1:20, or approximately 1:100 to approximately 1:30, or approximately 1:80 to approximately 1:35, or approximately 1:60 to approximately 1:

40.

6. The aerosol generating article according to claim 1, wherein the overlapping region extends along less than 15 percent, preferably less than 10 percent, and more preferably less than 5 percent, of the periphery of the aerosol-forming substrate portion.

7. The aerosol generating article according to claim 1, wherein the second straight line extends from the central axis to the center of the overlapping region.

8. The aerosol generating article according to claim 1, wherein the second straight line extends from the central axis to a glue line provided within the overlapping region.

9. The aerosol generating article according to claim 1, wherein the thickness of the substrate wrapper is measured in a region that is not the overlapping region.

10. The aerosol generating article according to claim 1, wherein the susceptor is an elongated, flat, planar susceptor strip in a direction parallel to the central axis, and preferably the susceptor strip has a length of 5 mm to 15 mm and a width of at least about 1 mm, preferably at least about 2 mm.

11. The aerosol generating article according to claim 1, wherein the susceptor is centrally located within the aerosol forming substrate portion.

12. In the direction parallel to the central axis, the length of the overlapping region is equal to or greater than the length of the susceptor. The aerosol generating article according to claim 1, wherein, in a direction perpendicular to the central axis, the width of the overlapping region is equal to or less than the width of the susceptor.

13. The aerosol generating article according to claim 1, wherein the susceptor comprises a metallic material, preferably aluminum.

14. A package comprising a plurality of aerosol-generating articles, wherein each aerosol-generating article within the package is the aerosol-generating article described in claim 1.

15. An aerosol generating system comprising an aerosol generating article according to claim 1, and an aerosol generating device including a heating chamber configured to insert the aerosol generating article at least partially into the heating chamber.

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