Aerosol generating article having a thick wrapper and a high-density substrate

Abstract

The present invention relates to an aerosol-generating article. The aerosol-generating article comprises an aerosol-forming substrate within an aerosol-forming substrate portion. The aerosol-generating article comprises a substrate wrapper that at least partially surrounds the aerosol-forming substrate portion. The substrate wrapper has a thickness of 50 micrometers or more. The substrate wrapper may include one or more layers having the same length in the longitudinal direction of the aerosol-generating article. The total density of the aerosol-forming substrate portion is more than 0.71 milligrams per cubic millimeter. The present invention further relates to an aerosol-generating system.

Description

Technical Field

[0001] The present disclosure relates to aerosol generating articles. The present disclosure further relates to aerosol generating systems.

Background Art

[0002] It is known to provide an aerosol generating device for generating inhalable vapor. Such a device 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 inserting the aerosol generating article into a heating chamber of the aerosol generating device.

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

Summary of the Invention

Problems to be Solved by the Invention

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

Brief Description of the Drawings

[0005]

Fig. 1a

Fig. 1b

Fig. 2a

Fig. 2b

Fig. 3a

Fig. 3b

Mode for Carrying Out the Invention

[0006] According to an embodiment of the present invention, an aerosol-generating article is provided. The aerosol-generating article may comprise an aerosol-forming substrate within an aerosol-forming substrate portion. The aerosol-generating article may comprise a substrate wrapper that at least partially surrounds the aerosol-forming substrate portion. The substrate wrapper may have a thickness of 50 micrometers or more. The substrate wrapper may comprise one or more layers having the same length in the longitudinal axis direction of the aerosol-generating article. The total density of the aerosol-forming substrate portion may be more than 0.71 milligrams per cubic millimeter.

[0007] According to an embodiment of the present invention, an aerosol-generating article is provided. The aerosol-generating article comprises an aerosol-forming substrate within an aerosol-forming substrate portion. The aerosol-generating article comprises a substrate wrapper that at least partially surrounds the aerosol-forming substrate portion. The substrate wrapper has a thickness of 50 micrometers or more. The substrate wrapper may include one or more layers having the same length in the longitudinal axis direction of the aerosol-generating article. The total density of the aerosol-forming substrate portion is more than 0.71 milligrams per cubic millimeter.

[0008] A combination of a thick substrate wrapper having a thickness of 50 micrometers or more and a total density of the aerosol-forming substrate portion that is more than 0.71 milligrams per cubic millimeter can provide an efficient aerosol-generating article without changing the outer diameter of the aerosol-generating article.

[0009] With a thick substrate wrapper having a thickness of 50 micrometers or more, the peripheral portion of the aerosol-forming substrate can be replaced with the wrapper material of the thick wrapper without changing the outer diameter of the aerosol-generating article. The thick wrapper can compensate for the thin diameter of the aerosol-forming substrate portion so that the outer diameter of the aerosol-generating article does not decrease. The outermost peripheral portion of the aerosol-forming substrate may not be sufficiently heated due to the distance to the heating element and the limited heat transfer when the aerosol-generating article is heated by an internal heating element. The insufficiently heated portion of the aerosol-forming substrate may not be heated sufficiently to participate in aerosolization during use. The thick wrapper can advantageously compensate for the insufficiently heated portion of the aerosol-forming substrate. Thus, the amount of the aerosol-forming substrate can be saved. A more efficient aerosol-generating article can be provided.

[0010] The total density of the aerosol-forming substrate portion that is more than 0.71 milligrams per cubic millimeter can enable a smaller total volume of the aerosol-forming substrate to be required compared to an aerosol-forming substrate with a low density.

[0011] With the thick wrapper, the diameter of the aerosol-forming portion surrounded by the thick wrapper can be decreased. With the thick wrapper, the internal volume of the aerosol-forming portion surrounded by the thick wrapper can be decreased. The decrease in the diameter of the aerosol-forming portion can improve the thermal contact between the aerosol-forming substrate and the susceptor provided within the aerosol-forming substrate portion. A more efficient aerosol-generating article can be provided.

[0012] The thick wrapper can be more rigid than a conventional thin wrapper. A mechanically more robust aerosol-generating article can be provided. A mechanically more robust aerosol-generating article can be particularly advantageous when the aerosol-generating article is arranged to be inserted into the heating chamber of an aerosol-generating device.

[0013] An aerosol-generating article that can be used in an existing aerosol-generating device can be provided without changing the outer diameter of the aerosol-generating article.

[0014] All combinations of one or more layers of the substrate wrapper may define an overall thickness of the substrate wrapper of 50 micrometers or more. At least one of the one or more layers of the substrate wrapper may have an individual thickness of 50 micrometers or more. Each of the one or more layers of the substrate wrapper may have an individual thickness of 50 micrometers or more.

[0015] The substrate wrapper may be disposed so as not to extend in a direction parallel to the longitudinal axis of the aerosol-generating article beyond the longitudinal axis end of the aerosol-forming substrate portion.

[0016] 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.

[0017] The substrate wrapper may have a uniform thickness that does not vary 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 at any point.

[0018] The ratio of the thickness of the base wrapper to the diameter of the aerosol-forming base portion may be 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.

[0019] The total density of the aerosol-forming base portion is at least 0.715 milligrams per cubic millimeter, preferably at least 0.720 milligrams per cubic millimeter, and more preferably about 0.725 milligrams per cubic millimeter.

[0020] At least 70 volume percent, preferably at least 75 volume percent, and more preferably at least about 79 volume percent of the internal volume of the aerosol-forming base portion may be filled with the aerosol-forming base and optionally one or more susceptor elements.

[0021] Less than 30 volume percent, preferably less than 25 volume percent, and more preferably less than about 21 volume percent of the internal volume of the aerosol-forming base portion may be empty.

[0022] The total mass of the aerosol-forming base is less than 300 milligrams, preferably less than 290 milligrams, and more preferably about 266 milligrams.

[0023] The draw resistance of the aerosol-forming base portion surrounded by the base wrapper is more than 10 millimeters of water column, preferably more than 20 millimeters of water column, and more preferably about 23 millimeters of water column.

[0024] The draw resistance of the aerosol-forming base portion surrounded by the base wrapper per millimeter length along the long axis direction of the aerosol-generating article is 1.7 millimeters of water column to 2.5 millimeters of water column, preferably about 1.9 millimeters of water column to 2.1 millimeters of water column, and more preferably about 2.1 millimeters of water column.

[0025] The density of the aerosol-forming substrate is more than 800 kilograms per cubic meter, preferably more than 825 kilograms per cubic meter, and more preferably about 842 kilograms per cubic meter.

[0026] The ratio obtained by dividing the total density of the aerosol-forming substrate portion by the total density of the aerosol-generating article at the position in the major axis direction of the aerosol-forming substrate portion may be greater than 1.0, preferably greater than 1.05, and more preferably 1.09 or more.

[0027] The matrix wrapper may have a density of 800 kilograms per cubic meter or less. The density of the matrix 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, and more preferably 400 kilograms per cubic meter or less, preferably 350 kilograms per cubic meter or less, and more preferably about 320 kilograms per cubic meter.

[0028] The density of the base wrapper may be 400 kilograms or less per cubic meter, and the base 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 base wrapper may have a thickness of about 148 micrometers. The density of the base wrapper may be 400 kilograms or less per cubic meter, and the base wrapper may have a thickness of 143 to 153 micrometers. The density of the base wrapper may be 400 kilograms or less per cubic meter, and the base wrapper may have a thickness of 140 to 160 micrometers.

[0029] The basis weight of the base wrapper may be less than 60 grams per square meter. The basis weight of the base wrapper may be more than 28 grams per square meter and less than 60 grams per square meter. The basis weight of the base wrapper may be more than 45 grams per square meter and less than 60 grams per square meter.

[0030] The basis weight of the base wrapper may be less than 50 grams per square meter. The basis weight of the base wrapper may be more than 28 grams per square meter and less than 50 grams per square meter. The basis weight of the base wrapper may be more than 45 grams per square meter and less than 50 grams per square meter. The basis weight of the base wrapper may be about 48 grams per square meter.

[0031] The base wrapper may have a thickness exceeding 145 micrometers and a density of 400 kilograms or less per cubic meter.

[0032] The matrix wrapper may include one or more perforations, or may not include any perforations.

[0033] The matrix wrapper may exhibit a wrapper permeability of more than 10 cholesteric units, more than 20 cholesteric units, more than 50 cholesteric units, more than 100 cholesteric units, more than 500 cholesteric units, more than 1000 cholesteric units, more than 1500 cholesteric units, more than 2000 cholesteric units, more than 2500 cholesteric units, more than 3000 cholesteric units, more than 3500 cholesteric units, or more than 4000 cholesteric units. The matrix wrapper may exhibit a wrapper permeability of from 10 cholesteric units to 10,000 cholesteric units, preferably from 50 cholesteric units to 8000 cholesteric units, more preferably from 100 cholesteric units to 5000 cholesteric units. The matrix wrapper may exhibit a wrapper permeability of from 4000 cholesteric units to 4800 cholesteric units, preferably from 4200 cholesteric units to 4600 cholesteric units, more preferably from 4300 cholesteric units to 4500 cholesteric units.

[0034] The matrix wrapper may have a thickness of more than 145 micrometers, a density of 400 kilograms or less per cubic meter, and a wrapper permeability of from 50 cholesteric units to 5000 cholesteric units, preferably from 4200 cholesteric units to 4600 cholesteric units, more preferably from 4300 cholesteric units to 4500 cholesteric units.

[0035] The permeability of the matrix wrapper can be determined using the international standard test method ISO 2965:2009, and the result can be expressed as cubic centimeters per square centimeter per minute and referred to as "cholesteric units".

[0036] The aerosol-generating article may comprise an additional wrapper surrounding the substrate wrapper. The additional wrapper may exhibit a permeability of less than 100 cholesterol units, less than 80 cholesterol units, less than 50 cholesterol units, less than 40 cholesterol units, or less than 30 cholesterol units. The permeability of the additional wrapper may be less than that of the substrate 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 substrate wrapper. The permeability of the additional wrapper may be less than 50 cholesterol units, and the permeability of the substrate wrapper may be from 4000 cholesterol units to 4800 cholesterol units, preferably from 4200 cholesterol units to 4600 cholesterol units, more preferably from 4300 cholesterol units to 4500 cholesterol units. The additional wrapper may be the tipping wrapper described herein. The additional wrapper may be a bonding wrapper. Advantageously, the additional wrapper may reduce the overall permeability when a substrate wrapper with high permeability is used.

[0037] The substrate wrapper may or may not be embossed. The substrate wrapper may be both perforated and embossed.

[0038] The term "embossing" is used herein to refer to protrusions formed on the surface of the wrapper. These protrusions may be engraved, shaped, or stamped onto the wrapper. A portion of the wrapper with such embossing is said to be embossed.

[0039] The base wrapper may include embossed portions. The embossed portion of the base wrapper may have one emboss. The embossed portion of the base wrapper may have a plurality of embosses. One or more embosses may have a depth of 0.07 millimeters to 0.21 millimeters, preferably 0.10 millimeters to 0.18 millimeters, more preferably 0.12 millimeters to 0.16 millimeters. Each emboss may also have a pitch of 0.2 millimeters to 0.4 millimeters, preferably 0.25 millimeters to 0.35 millimeters, more preferably 0.275 millimeters to 0.325 millimeters.

[0040] The base wrapper may have a roughness of about 50 Bekk seconds to about 1000 Bekk seconds, preferably about 100 Bekk seconds to about 200 Bekk seconds. The roughness expressed in Bekk seconds can be measured by a standard test using a BEKK Smoothness Tester that 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 approved by the international standard ISO 5627.

[0041] As used herein, "total density of the aerosol-forming substrate portion" refers to the total mass of the material received within the volume enclosed by the base wrapper divided by the volume enclosed by the base wrapper. The mass of the base wrapper itself and any additional wrapper enclosing the base wrapper is not considered. The volume of the base wrapper itself and any additional wrapper enclosing the base wrapper is not considered.

[0042] The total density of the aerosol-forming substrate portion can be determined after conditioning the aerosol-generating article in accordance with ISO standard 3402:1999. The aerosol-forming substrate is removed from the aerosol-forming substrate portion and weighed. If a susceptor is present, 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 may 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, if present, the mass of the susceptor by the internal volume of the substrate portion. This may be repeated 20 times for 20 different individual aerosol-generating articles in order to obtain an average value.

[0043] As used herein, "the total density of the aerosol-generating article at the longitudinal position of the aerosol-forming substrate portion" refers to the total mass of the material received within the volume defined by the average cross-sectional area of the aerosol-generating article along the length of the aerosol-forming substrate portion, divided by that volume. The mass of each of the aerosol-forming substrate, any optional susceptor, the substrate wrapper, and any one or more optional further wrappers surrounding the substrate wrapper is considered. The volume of each of the substrate wrapper itself and any one or more optional further wrappers surrounding the substrate wrapper is considered.

[0044] "The total density of the aerosol-generating article at the longitudinal position of the aerosol-forming substrate portion" can be determined after conditioning the aerosol-generating article in accordance with ISO standard 3402:1999.

[0045] The thickness of the base wrapper may be determined in accordance with ISO 534:2011. The density of the base wrapper may be determined in accordance with ISO 534:2011. The thickness of the base wrapper can be determined in accordance with ASTM E252-06(2021)e1. Generally, for an embossed base wrapper, the local thickness at the embossing position may be smaller than the thickness at a position without embossing. As used herein, for an embossed wrapper, the thickness of the base wrapper refers to the thickness at a position without embossing. For an embossed wrapper, the thickness of the base wrapper may be determined before the wrapper is embossed.

[0046] Unless otherwise defined, all measurements described herein are performed after adjusting the sample in accordance with ISO standard 3402:1999.

[0047] The density of the base wrapper can be calculated by dividing the basis weight of the base wrapper by the thickness of the base wrapper. The basis weight, also called the grammage, refers to the mass of the base wrapper per sheet size and is usually expressed in grams per square meter. The basis weight can be obtained, for example, by weighing a 1 square meter sheet of the base wrapper.

[0048] When referring to the base wrapper, the term "lightweight" as used herein means that the density of the base wrapper is 800 kilograms or less per cubic meter, preferably 750 kilograms or less per cubic meter, more preferably 700 kilograms or less per cubic meter, more preferably 650 kilograms or less per cubic meter, more preferably 600 kilograms or less per cubic meter, more preferably 550 kilograms or less per cubic meter, more preferably 500 kilograms or less per cubic meter, more preferably 450 kilograms or less per cubic meter, more preferably 400 kilograms or less per cubic meter, more preferably 350 kilograms or less per cubic meter, and more preferably about 320 kilograms per cubic meter.

[0049] When referring to the substrate wrapper, the term "thick" as used herein means that the thickness of the substrate wrapper is 50 micrometers or more, preferably 60 micrometers or more, 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.

[0050] The substrate wrapper can 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 can 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, 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.

[0051] The substrate wrapper may be in direct physical contact with the aerosol-forming substrate. In that case, there is no layer of material between the substrate wrapper and the aerosol-forming substrate.

[0052] The base wrapper may be formed from a single continuous material sheet. The single continuous sheet may be wound around the aerosol-forming substrate portion in approximately one wrap. Generally, the single continuous sheet may be wound around the substrate portion slightly more than one wrap to form an overlapping region of the opposing end portions of the base wrapper. The thickness of the wrapper is not measured in the overlapping region. Thus, a base wrapper formed from a single continuous material sheet may include only a single layer, excluding any optional overlapping regions, if present.

[0053] The base wrapper may be formed from a single continuous sheet wound around the aerosol-forming substrate portion at least about two or more wraps. In that case, two or more layers of the base wrapper are wound around the aerosol-forming substrate portion without taking into account the additional overlapping regions formed by the overlapping opposing end portions of the wrapper. In that case, the thickness of the base wrapper may be obtained by multiplying the thickness of an individual layer, i.e., the thickness of the sheet, by the number of wraps. The thickness of the base wrapper is not obtained by multiplying the thickness of an individual layer by the number of wraps of the overlapping regions formed by the overlapping opposing end portions of the wrapper. None of the individual layers extends beyond the ends of the aerosol-forming substrate portion in the longitudinal direction of the aerosol-generating article.

[0054] The base wrapper may include one or more of cardboard, plastic, and metal foil.

[0055] The base wrapper may include one or more of cellulosic materials such as paper, wood, fabric, natural fibers, and artificial fibers. The base wrapper may include a paper layer. The base wrapper may be made of a single paper sheet. The base wrapper may include a single paper layer wound around the aerosol-forming substrate portion, excluding any optional overlapping portions. The base wrapper may be made of a single paper sheet wound around the aerosol-forming substrate portion two or more times, resulting in a base wrapper that includes two or more layers having the same length.

[0056] The base 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.

[0057] The base wrapper may include a laminated sheet. The base wrapper may be made of a single laminated sheet. The laminated sheet may be a laminate of a paper layer and an aluminum layer.

[0058] The wrapper may be formed from a laminated material including multiple layers. The wrapper may be formed of a co-laminated sheet of metal, such as a co-laminated sheet of aluminum. The metal layer of the co-laminated 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-laminated sheet may have a thickness of 2 micrometers to 15 micrometers, preferably 3 micrometers to 12 micrometers, more preferably 5 micrometers to 10 micrometers.

[0059] The base 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.

[0060] The base wrapper may include a flame-retardant composition containing one or more flame-retardant compounds. The term "flame-retardant compound" is used herein to describe a compound that provides varying degrees of flammability protection to a carrier substrate when added to or otherwise incorporated into a carrier substrate such as a paper or plastic compound.

[0061] Numerous suitable flame-retardant compounds are known to those skilled in the art. Specifically, several flame-retardant compounds and formulations suitable for the treatment of cellulosic materials are known and disclosed and may be found to be useful in the manufacture of wrappers for aerosol-generating articles according to the present invention.

[0062] The base wrapper may be a base wrapper system formed from two or more individual base wrapper sub - sheets. In that case, the thickness of the base wrapper can be obtained by adding the thicknesses of the individual base wrapper sub - sheets of the base wrapper system. Any of the individual base wrapper sub - sheets may not extend in the longitudinal direction of the aerosol - generating article beyond the end of the aerosol - forming base portion. Each of the individual base wrapper sub - sheets forming the base wrapper system may be of the same length in a direction parallel to the longitudinal axis of the aerosol - generating article.

[0063] The base wrapper may be a base wrapper system formed from two or more individual base wrapper sub - sheets. Each of the two or more individual base wrapper sub - sheets at least partially surrounds the aerosol - forming base portion. None of the two or more individual base wrapper sub - sheets extends in the longitudinal direction of the aerosol - generating article beyond the end of the aerosol - forming base portion. Each of the two or more individual base wrapper sub - sheets has a thickness of 50 micrometers or more and a density of 800 kilograms per cubic meter or less. Preferably, each of the individual base wrapper sub - sheets forming the base wrapper system has the same length in a direction parallel to the longitudinal axis of the aerosol - generating article.

[0064] The base wrapper may be a base wrapper system formed from two or more individual base wrapper sub - sheets. Each of the two or more individual base wrapper sub - sheets at least partially surrounds the aerosol - forming base portion. Each of the two or more individual base wrapper sub - sheets has the same length in the longitudinal direction of the aerosol - generating article. Each of the two or more individual base wrapper sub - sheets has a thickness of 50 micrometers or more and a density of 800 kilograms per cubic meter or less.

[0065] The base wrapper may be a base wrapper system formed from two or more individual base wrapper subsheets, each of the two or more individual base wrapper subsheets at least partially surrounds the aerosol-forming substrate portion, and none of the two or more individual base wrapper subsheets extends in the longitudinal axis direction of the aerosol-generating article beyond the end of the aerosol-forming substrate portion. The sum of the two or more individual base wrapper subsheets has a thickness of 50 micrometers or more and a density of 800 kilograms or less per cubic meter. Preferably, each of the individual base wrapper subsheets forming the base wrapper system has the same length in a direction parallel to the longitudinal axis of the aerosol-generating article.

[0066] The base wrapper may be a base wrapper system formed from two or more individual base wrapper subsheets, each of the two or more individual base wrapper subsheets at least partially surrounds the aerosol-forming substrate portion, each of the two or more individual base wrapper subsheets has the same length in the longitudinal axis direction of the aerosol-generating article, and the sum of the two or more individual base wrapper subsheets has a thickness of 50 micrometers or more and a density of 800 kilograms or less per cubic meter.

[0067] The substrate wrapper system may be formed from two separate sheets. The substrate wrapper system may be formed from a first separate sheet and a second separate sheet. The first individual sheet may be provided by a first wrapper and include a first overlapping region formed by overlapping opposing end portions of the first wrapper. The second individual sheet may be provided by a second wrapper and include a second overlapping region formed by overlapping opposing end portions of the second wrapper. The first overlapping region may be offset from the second overlapping region by at least about 5 percent, preferably at least about 10 percent, more preferably at least about 15 percent, and more preferably from about 40 percent to about 60 percent around the aerosol-forming substrate portion. One or both of the first and second individual sheets may be paper wrappers.

[0068] 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 the present disclosure.

[0069] 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.

[0070] The length of the downstream section may be less than 70 millimeters, or less than 60 millimeters, or less than 50 millimeters.

[0071] For example, the length of the downstream section may be from 20 millimeters to 70 millimeters, or from 25 millimeters to 60 millimeters, or from 30 millimeters to 50 millimeters.

[0072] The downstream section of the aerosol generating article according to the present invention preferably includes a hollow tubular cooling element provided downstream of the aerosol-forming substrate portion. The hollow tubular cooling element may advantageously provide an aerosol cooling element for the aerosol generating article.

[0073] 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 against 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.

[0074] As used throughout this disclosure, the term "hollow tubular element" generally means an elongated element that defines a lumen or air flow path along its longitudinal axis. In particular, the term "tubular" is used hereinafter with respect to a tubular element that has a substantially cylindrical cross-section and defines at least one air flow conduit that establishes unbroken fluid communication between the upstream end of the tubular element and the downstream end of the tubular element. However, of course, alternative shapes of the tubular element (e.g., alternative cross-sectional shapes) may be possible. The hollow tubular cooling element may be a separate individual element of the aerosol generating article having a defined length and thickness.

[0075] In the context of the present invention, the hollow tubular cooling element provides an unobstructed flow channel. This means that the hollow tubular cooling element provides a negligible level of pull - through resistance (RTD). The term "negligible level of RTD" is used to indicate an RTD of less than 1 millimeter of water column per 10 millimeters of the length of the hollow tubular cooling element, preferably less than 0.4 millimeter of water column per 10 millimeters of the length of the hollow tubular cooling element, more preferably less than 0.1 millimeter of water column per 10 millimeters of the length of the hollow tubular cooling element.

[0076] The RTD of the hollow tubular cooling element is preferably 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, or 1 millimeter of water column or less.

[0077] The RTD of the hollow tubular cooling 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.

[0078] In the aerosol - generating article according to the present invention, the overall RTD of the article essentially depends on the RTD of the rod and optionally the RTD of downstream and / or upstream elements. This is because the hollow tubular cooling element is substantially empty and thus contributes only negligibly to the overall RTD of the aerosol - generating article.

[0079] Therefore, the flow channel should not include any components that would impede the axial air flow. The flow channel is preferably substantially empty, and particularly preferably empty.

[0080] As described in more detail within the present disclosure, the aerosol-generating article may comprise a ventilation zone at a location along the downstream section. In some embodiments, the aerosol-generating article may comprise a ventilation zone at a location along a hollow tubular cooling element. Such, or any, ventilation zone may extend through the peripheral wall of the hollow tubular cooling element. In this way, fluid communication is established between the flow channel internally defined by the hollow tubular cooling element and the external environment. The ventilation zone is further described within the present disclosure.

[0081] The length of the hollow tubular cooling element may be at least 15 millimeters, or at least 20 millimeters, or at least 25 millimeters. The length of the hollow tubular cooling element may 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 may be from 15 millimeters to 50 millimeters, or from 20 millimeters to 45 millimeters, or from 20 millimeters to 40 millimeters, or from 20 millimeters to 30 millimeters, or from 25 millimeters to 40 millimeters.

[0082] 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 the nucleation of aerosol particles generated by the substrate. Providing a relatively long cavity maximizes the advantages of such nucleation, thereby improving aerosol formation and cooling.

[0083] The wall thickness of the hollow tubular cooling element may be from 100 micrometers to 2 millimeters, or from 150 micrometers to 1.5 millimeters, or from 200 micrometers to 1.25 millimeters.

[0084] The hollow tubular cooling element preferably has an outer diameter that is approximately equal to the outer diameter of the aerosol-generating article.

[0085] The hollow tubular cooling element may have an outer diameter of 5 millimeters to 10 millimeters, for example, 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.

[0086] 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.

[0087] 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.

[0088] By providing a hollow tubular cooling element having an inner diameter as presented above, advantageously, sufficient rigidity and strength can be provided to the hollow tubular cooling element.

[0089] 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.

[0090] The provision of a hollow tubular cooling element having an inner diameter as presented above may advantageously reduce the draw resistance of the hollow tubular cooling element.

[0091] 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.

[0092] 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.

[0093] The hollow tubular cooling element may include a paper-based material. The hollow tubular cooling element may include at least one layer of paper. The paper can be very stiff paper. The paper can be crimped paper such as heat-resistant crimped paper or crimped sulfuric acid paper.

[0094] Preferably, the hollow tubular cooling element may include cardboard. The hollow tubular cooling element can be a cardboard tube. The hollow tubular cooling element can be formed from cardboard. Advantageously, cardboard provides a balance between being deformable to facilitate insertion of an article into the aerosol generating device and being sufficiently rigid to provide proper engagement of the article with the interior of the device, and is a cost-effective material. Thus, the cardboard tube may provide adequate resistance to deformation or compression during use.

[0095] 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 a plurality of 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.

[0096] The hollow tubular cooling element may include a polymer material. For example, the hollow tubular cooling element can include a polymer film. The polymer film can include a cellulose film. The hollow tubular cooling element can include low-density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers. The hollow tube can include cellulose acetate tow.

[0097] When the hollow tubular cooling element includes cellulose acetate tow, the cellulose acetate tow can have 2 to 4 denier per filament and a total denier of 25 to 40.

[0098] The aerosol generating article according to the present invention preferably comprises a ventilation zone at a location along the downstream section. More specifically, in those embodiments where the downstream section comprises a hollow tubular cooling element, the ventilation zone may be provided at a location along the hollow tubular cooling element. Alternatively or additionally, in those embodiments where the downstream section comprises a downstream hollow tubular element, the ventilation zone may be provided at a location along the downstream hollow tubular element.

[0099] Thus, a ventilated cavity is provided downstream of the aerosol-forming substrate portion. This provides several potential technical advantages. First, the inventors have found that one such ventilated hollow tubular cooling element provides particularly efficient cooling of the aerosol. Second, the inventors have surprisingly found that such rapid cooling of the volatile species released upon heating of the aerosol-forming substrate enhances the nucleation of aerosol particles.

[0100] The ventilation zone may typically include a plurality of perforations through the circumferential wall of the hollow tubular cooling element. The ventilation zone preferably 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 from 8 to 30 perforations.

[0101] The aerosol generating article according to the present invention may have a ventilation level of at least 40 percent. By increasing the ventilation level, the level of aerosol cooling may be increased. 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. Accordingly, the ventilation level may be selected based on the desired temperature and composition of the aerosol delivered to the user.

[0102] The aerosol-generating article preferably has a ventilation level of at least 45 percent, more preferably at least 50 percent, more preferably at least 60 percent, and more preferably at least 70 percent.

[0103] The aerosol-generating article according to the present invention may have a ventilation level of 90 percent or less, more preferably 85 percent or less, and more preferably 80 percent or less.

[0104] Therefore, the aerosol-generating article according to the present invention may have a ventilation level of 45 percent to 90 percent, more preferably 45 percent to 85 percent, and even more preferably 45 percent to 80 percent. The aerosol-generating article according to the present invention may have a ventilation level of 50 percent to 90 percent, preferably 50 percent to 85 percent, and more preferably 50 percent to 80 percent. The aerosol-generating article according to the present invention may have a ventilation level of 60 percent to 90 percent, preferably 60 percent to 85 percent, and more preferably 60 percent to 80 percent. The aerosol-generating article according to the present invention may have a ventilation level of 70 percent to 90 percent, preferably 70 percent to 85 percent, and more preferably 70 percent to 80 percent.

[0105] For example, the aerosol-generating article may have a ventilation level of about 75 percent.

[0106] As discussed in the present 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 the mouth-side end filter.

[0107] The downstream filter segment may be located downstream of the hollow tubular cooling element, as described above. The downstream filter segment may extend between the hollow tubular cooling element and the downstream end of the aerosol-generating article.

[0108] The downstream filter segment is preferably a solid plug, which may also be described as a "plane" plug and is non-tubular. Thus, the filter segment preferably has a substantially uniform cross-section.

[0109] 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.

[0110] 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 an end-to-end abutting relationship with each other.

[0111] The downstream filter segment may optionally contain a flavorant provided in any suitable form. For example, the downstream filter segment may comprise one or more capsules, beads, or granules of flavorant, or threads or filaments filled with one or more flavors.

[0112] The downstream filter segment preferably has a low particle filtration efficiency.

[0113] The downstream filter segment is preferably surrounded by a 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.

[0114] The downstream filter segment is preferably connected by a tipping wrapper to one or more of the adjacent upstream components of the aerosol-generating article.

[0115] The downstream filter segment preferably has an outer diameter that is 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.

[0116] The outer diameter of the downstream filter segment may be 5 millimeters to 10 millimeters, or 5.5 millimeters to 9 millimeters, or 6 millimeters to 8 millimeters. In certain embodiments, the exterior of the downstream filter segment is less than 7 millimeters.

[0117] Unless otherwise specified, the draw resistance (RTD) of a component or aerosol-generating article is measured in accordance with ISO 6565-2015. The 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, which are normally carried out at a temperature of 22 degrees Celsius, a pressure of 101 kPa (about 760 Torr), and a relative humidity of 60%, with a volumetric flow rate of 17.5 milliliters per second at the output or downstream end of the component being measured. The conditions for smoking and the specifications of the smoking machine are presented in ISO standard 3308 (ISO 3308:2000). The atmosphere for conditioning and testing is presented in ISO standard 3402 (ISO 3402:1999).

[0118] The draw resistance (RTD) may be expressed in pressure units of "millimeters of water column" (mmWG).

[0119] The drawdown resistance (RTD) of the downstream section may be at least 0 millimeter 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 12 millimeters of water column or less. The RTD of the downstream section may be 11 millimeters of water column or less. The RTD of the downstream section may be 10 millimeters of water column or less.

[0120] The drawdown resistance (RTD) characteristics of the downstream section may be entirely or mostly due to the RTD characteristics of the downstream filter segment of the downstream section. In other words, the RTD of the downstream filter segment of the downstream section may fully define the RTD of the downstream section.

[0121] The drawdown resistance (RTD) of the downstream filter segment may be at least 0 millimeter 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 12 millimeters of water column or less, or 11 millimeters of water column or less, or 10 millimeters of water column or less.

[0122] As described above, the downstream filter segment may be formed of a fibrous material. The downstream filter segment may be formed of a porous material. The downstream filter segment may be formed of a biodegradable material. The downstream filter segment may be formed of 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 to 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 fibers of 12 denier per filament.

[0123] The downstream filter segment can be formed of a polylactic acid-based material. The downstream filter segment can be formed of a bioplastic material, preferably a starch-based bioplastic material. The downstream filter segment can be produced by injection molding or extrusion molding. The bioplastic-based material is advantageous because it can provide a downstream filter segment structure that is easy and inexpensive to manufacture due to a specific complex cross-sectional profile that includes a plurality of relatively large air flow channels extending through the downstream filter segment material to provide suitable RTD characteristics.

[0124] The length of the downstream filter segment may be at least 5 millimeters, or at least 10 millimeters. The length of the downstream filter segment may be less than 25 millimeters, or less than 20 millimeters. For example, the length of the downstream filter segment may be 5 millimeters to 25 millimeters, or 10 millimeters to 25 millimeters, or 5 millimeters to 20 millimeters, or 10 millimeters to 20 millimeters.

[0125] The downstream section may further comprise one or more additional hollow tubular elements.

[0126] In certain embodiments, the downstream section may comprise a hollow tubular support element upstream of the hollow tubular cooling element described above. 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. The hollow tubular support element and the hollow tubular cooling element are preferably adjacent to each other and together provide a hollow tubular section within the downstream section.

[0127] 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, crumpled paper (such as crumpled heat-resistant paper or crumpled sulfuric acid 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.

[0128] The hollow tubular support element preferably has an outer diameter that is approximately equal to the outer diameter of the aerosol-generating article.

[0129] The hollow tubular support element may have an outer diameter of 5 millimeters to 10 millimeters, for example, 5.5 millimeters to 9 millimeters, or 6 millimeters to 8 millimeters. In a preferred embodiment, the hollow tubular support element has an outer diameter of less than 7 millimeters.

[0130] The hollow tubular support element may have a wall thickness of at least 1 millimeter, preferably at least 1.5 millimeters, more preferably at least 2 millimeters.

[0131] 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 about 7 millimeters.

[0132] 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.

[0133] In some embodiments, the hollow tubular support element has a length of from 5 millimeters to 15 millimeters, preferably from 6 millimeters to 15 millimeters, more preferably from 7 millimeters to 15 millimeters. In other embodiments, the hollow tubular support element has a length of from 5 millimeters to 12 millimeters, preferably from 6 millimeters to 12 millimeters, more preferably from 7 millimeters to 12 millimeters. In further embodiments, the support element has a length of from 5 millimeters to 10 millimeters, preferably from 6 millimeters to 10 millimeters, more preferably from 7 millimeters to 10 millimeters.

[0134] As an alternative to, 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.

[0135] 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 the mouth-side end cavity of the aerosol-generating article.

[0136] In certain embodiments, an additional downstream hollow tubular element may be provided such that the downstream section comprises two adjacent downstream hollow tubular elements downstream of the downstream filter segment.

[0137] 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.

[0138] Therefore, the air flow channel of the downstream hollow tubular element should not include any component that would impede the flow of air in the long axis direction. The flow channel is preferably substantially empty, and particularly preferably empty.

[0139] The length of the downstream hollow tubular element is preferably 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.

[0140] 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.

[0141] The downstream hollow tubular element may include a paper-based material. The downstream hollow tubular element may include at least one layer of paper. The paper can be very hard paper. The paper can be curled paper such as heat-resistant curled paper or curled sulfuric acid paper. The downstream hollow tubular element may include cardboard. The downstream hollow tubular element can be a cardboard tube.

[0142] 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 a plurality of 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.

[0143] The downstream hollow tubular element may contain a polymer material. For example, the downstream hollow tubular element can include a polymer film. The polymer film can include a cellulose film. The downstream hollow tubular element can include low density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers. The downstream hollow tubular element preferably comprises cellulose acetate tow. For example, in a preferred embodiment, the downstream hollow tubular element includes a hollow acetate tube.

[0144] When the downstream hollow tubular element contains cellulose acetate tow, the cellulose acetate tow can have 2 to 4 denier per filament and a total denier of 25 to 40.

[0145] When the downstream section further comprises the additional downstream hollow tubular element described above, the additional downstream hollow tubular element may be formed of the same material as, or a different material from, the downstream hollow tubular element.

[0146] In a particular preferred embodiment, the downstream section may comprise a ventilation zone at a position on the downstream hollow tubular element. In one example, this ventilation zone at a position on the downstream hollow tubular element can be provided in place of the ventilation zone at a position on the hollow tubular cooling element. In another example, the ventilation zone at a position on the downstream hollow tubular element can be provided in addition to the ventilation zone provided at a position on the hollow tubular cooling element.

[0147] The ventilation zone at a position along the downstream hollow tubular element may include a plurality of perforations through the peripheral wall of the downstream hollow tubular element. The ventilation zone at a position along the downstream hollow tubular element preferably 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 8 to 30 perforations.

[0148] 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 a hollow acetate tube (HAT) or a fine hollow acetate tube (FHAT). Such hollow tubes may be made of cellulose acetate and are cylindrical components provided with an axially disposed hole in the center. The dimensions of the hollow tube, such as the outer diameter of the hollow tube, the outer diameter or diameter of the hole, vary and can be designed according to the requirements of each product.

[0149] The HAT may have a length of 6 millimeters to 10 millimeters, preferably 7 millimeters to 9 millimeters, more preferably about 8 millimeters. The HAT may be disposed downstream of the aerosol forming substrate portion, preferably in direct contact with the aerosol forming substrate portion downstream of the aerosol forming substrate portion. The HAT may function as one or more of an air flow cooling element and an air flow accelerating element.

[0150] The FHAT may be disposed downstream of the HAT, preferably directly adjacent to the HAT downstream of 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 about twice the inner diameter of the HAT. The FHAT may function as an air flow decelerating element.

[0151] The aerosol-generating article may comprise 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 and in direct abutment with the FHAT.

[0152] The mouth-end filter may comprise 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.

[0153] The length of the mouth-end filter along the longitudinal axis of the aerosol-generating article may be from 10 millimeters to 14 millimeters, preferably from 11 millimeters to 13 millimeters, more preferably about 12 millimeters.

[0154] The draw resistance of the mouth-end filter may be from 1 millimeter water column to 100 millimeters water column, preferably from 2 millimeters water column to 50 millimeters water column, more preferably from 5 millimeters water column to 40 millimeters water column, more preferably from 10 millimeters water column to 30 millimeters water column, more preferably from 16 millimeters water column to 20 millimeters water column, more preferably from 17 millimeters water column to 19 millimeters water column, and more preferably about 18 millimeters water column. The draw resistance of the mouth-end filter per millimeter length along the longitudinal axis of the aerosol-generating article may be from 0.1 millimeter water column to 20 millimeters water column, preferably from 0.2 millimeter water column to 10 millimeters water column, more preferably from 0.5 millimeter water column to 5 millimeters water column or more, more preferably from 1 millimeter water column to 2 millimeters water column or more, more preferably from 1.3 millimeters water column to 1.7 millimeters water column, more preferably from 1.4 millimeters water column to 1.6 millimeters water column, and more preferably about 1.5 millimeters water column.

[0155] The aerosol-generating article according to the present disclosure may 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.

[0156] 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 serves to prevent loss of the substrate, which can be advantageous, for example, when the substrate contains particulate plant material.

[0157] If the upstream segment of the aerosol-forming substrate portion includes shredded tobacco, such as tobacco cut filler, the upstream section or its elements may additionally serve to prevent loss of loose particles of tobacco from the upstream end of the article. This can be particularly important, for example, when the density of the shredded tobacco is relatively low.

[0158] The upstream element may be a porous plug element. The upstream element preferably has a porosity of at least 50 percent in the longitudinal axis direction of the aerosol-generating article. More preferably, the upstream element has a porosity of 50 percent to 90 percent in the longitudinal axis direction. The porosity of the upstream element in the longitudinal axis direction is defined by 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.

[0159] The upstream element may be made of a porous material or may comprise a plurality of openings. This can be achieved, for example, by laser perforation. The plurality of openings are preferably uniformly distributed across the cross-section of the upstream element.

[0160] The porosity or permeability of the upstream element may advantageously be designed to provide an aerosol-generating article having a specific overall draw resistance (RTD) that does not substantially affect the filtration provided by other parts of the article.

[0161] 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 air flows into the aerosol-forming substrate portion via suitable ventilation means provided within the wrapper.

[0162] In certain preferred embodiments of the present invention, it may be desirable to minimize the RTD of the upstream element. For example, this may apply to articles 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 as low an RTD as possible such that most of the RTD experience by the consumer is provided by the aerosol-generating device rather than the article.

[0163] 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 millimeter of water column, or at least 0.25 millimeter of water column, or at least 0.5 millimeter of water column. The upstream element preferably has an RTD of less than 2 millimeters of water column per millimeter length, more preferably less than 1.5 millimeters of water column per millimeter length, more preferably less than 1 millimeter of water column per millimeter length, more preferably less than 0.5 millimeter of water column per millimeter length, more preferably less than 0.3 millimeter of water column per millimeter length, more preferably less than 0.2 millimeter of water column per millimeter length.

[0164] Preferably, the combined RTD of the upstream section or its upstream elements, and the aerosol-forming substrate portion is less than 15 millimeters of water column, more preferably less than 12 millimeters of water column, and even more preferably less than 10 millimeters of water column.

[0165] 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 "plane" element. The solid plug element may be porous as described above, but does not have a tubular form and thus does not provide a longitudinal flow channel. The solid plug element preferably has a substantially uniform cross-section.

[0166] In other preferred embodiments, the upstream element is formed from a hollow tubular segment that defines a longitudinal cavity providing an unrestricted flow channel. In such embodiments, the upstream element can provide protection to the aerosol-forming substrate as described above, while having a minimal effect on the overall draw resistance (RTD) and filtration characteristics of the article.

[0167] 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, even more preferably at least 4 millimeters, and even 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 its upstream elements.

[0168] Preferably, the wall thickness of the hollow tubular segment is less than 2 millimeters, more preferably less than 1.5 millimeters, and even more preferably less than 1 millimeter.

[0169] 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 for one of the other components of the aerosol-generating article, such as, for example, a downstream filter segment or a hollow tubular cooling element. Suitable materials for forming the upstream element include filter materials, ceramics, polymeric materials, cellulose acetate, cardboard, zeolites, or aerosol-forming substrates. The upstream element may include a plug of cellulose acetate. The upstream element may comprise a hollow acetate tube or a cardboard tube.

[0170] The upstream element is preferably formed from a heat-resistant material. For example, the upstream element is preferably formed from a material that can withstand a temperature of up to 350 degrees Celsius. This ensures that the upstream element is not adversely affected by the heating means for heating the aerosol-forming substrate.

[0171] The upstream section or its upstream element preferably has an outer diameter that is approximately equal to the outer diameter of the aerosol-generating article. Preferably, the outer diameter of the upstream section or its upstream element is 5 millimeters to 8 millimeters, more preferably 5.25 millimeters to 7.5 millimeters, and even more preferably 5.5 millimeters to 7 millimeters.

[0172] Preferably, the upstream section or the upstream element has a length of 2 millimeters to 10 millimeters, more preferably 3 millimeters to 8 millimeters, and even more preferably 2 millimeters to 6 millimeters. In a particularly preferred embodiment, the upstream section or the upstream element has a length of 5 millimeters.

[0173] The upstream section is preferably surrounded by a wrapper such as a plug wrap. The wrapper surrounding the upstream section is preferably a rigid 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. Thereby, structural rigidity is provided to the upstream section.

[0174] The upstream section is preferably connected by an outer wrapper to the aerosol-forming substrate portion and optionally to at least a part of the downstream section.

[0175] The aerosol-generating article may comprise an upstream section including a front plug. The front plug may be disposed upstream of and in direct contact with 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 from 1 millimeter to 10 millimeters, preferably from 3 millimeters to 7 millimeters, more preferably from 4 millimeters to 6 millimeters, and even more preferably about 5 millimeters. The front plug may be in the form of a complete cylinder.

[0176] 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, and more preferably 0.022 to 0.024.

[0177] 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, and more preferably less than 1 percent. Optionally, the outer diameter of the front plug is 7.1 millimeters.

[0178] The front plug may be surrounded by a front plug wrapper. The ratio of the thickness of the front plug wrapper to the thickness of the base wrapper may be 0.7 or less, more preferably 0.5 or less, more preferably 0.3 or less, and more preferably 0.2 or less.

[0179] Any part of the front plug may not be surrounded by the base wrapper.

[0180] The withdrawal resistance of the front plug may be 1 millimeter of water column to 150 millimeters of water column, preferably 1 millimeter of water column to 50 millimeters of water column, more preferably 1 millimeter of water column to 20 millimeters of water column, and more preferably 1 millimeter of water column to 10 millimeters of water column. The withdrawal resistance of the front plug may be about 10 millimeters of water column or less.

[0181] The front plug may assist in maintaining the cleanliness of the aerosol generating device by capturing the slurry within the consumable. The front plug may prevent the aerosol forming substrate or the heating element from falling from the aerosol generating article.

[0182] The aerosol generating article according to the present invention may have an overall length of at least 40 millimeters, or at least 50 millimeters, or at least 60 millimeters.

[0183] The overall length of the aerosol generating article according to the present invention may be 90 millimeters or less, or 85 millimeters or less, or 80 millimeters or less.

[0184] In some embodiments, the overall length of the aerosol-generating article is preferably from 50 millimeters to 90 millimeters, more preferably from 60 millimeters to 90 millimeters, and even more preferably from 70 millimeters to 90 millimeters. In other embodiments, the overall length of the aerosol-generating article is preferably from 50 millimeters to 85 millimeters, more preferably from 60 millimeters to 85 millimeters, and even more preferably from 70 millimeters to 85 millimeters. In further embodiments, the overall length of the aerosol-generating article is preferably from 50 millimeters to 80 millimeters, more preferably from 60 millimeters to 80 millimeters, and even more preferably from 70 millimeters to 80 millimeters. In an exemplary embodiment, the overall length of the aerosol-generating article is 75 millimeters.

[0185] In some embodiments, the overall length of the aerosol-generating article is preferably from 40 millimeters to 70 millimeters, more preferably from 45 millimeters to 70 millimeters. In other embodiments, the overall length of the aerosol-generating article is preferably from 40 millimeters to 60 millimeters, more preferably from 45 millimeters to 60 millimeters. In further embodiments, the overall length of the aerosol-generating article is preferably from 40 millimeters to 50 millimeters, more preferably from 45 millimeters to 50 millimeters. In an exemplary embodiment, the overall length of the aerosol-generating article is about 45 millimeters.

[0186] 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.

[0187] 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.

[0188] The aerosol-generating article may have an outer diameter of 5 millimeters to 8 millimeters, or 5 millimeters to 7.5 millimeters, or 5 millimeters to 7 millimeters, or 5.25 millimeters to 8 millimeters, or 5.25 millimeters to 7.5 millimeters, or 5.25 millimeters to 7 millimeters, or 5.5 millimeters to 8 millimeters, or 5.5 millimeters to 7.5 millimeters, or 5.5 millimeters to 7 millimeters.

[0189] The outer diameter of the aerosol-generating article may be substantially constant over the entire length of the article. Alternatively, different portions of the aerosol-generating article may have different outer diameters.

[0190] The overall RTD of the aerosol-generating article is preferably at least 10 millimeter water columns. For example, the overall RTD of the aerosol-generating article may be at least 20 millimeter water columns, at least 30 millimeter water columns, at least 35 millimeter water columns, or at least 40 millimeter water columns.

[0191] The overall RTD of the aerosol-generating article may be 70 millimeter water columns or less. For example, the overall RTD of the aerosol-generating article may be 65 millimeter water columns or less, 60 millimeter water columns or less, or 55 millimeter water columns or less, or 50 millimeter water columns or less.

[0192] The overall RTD of the aerosol-generating article may be 10 millimeter water columns to 70 millimeter water columns. For example, the overall RTD of the aerosol-generating article may be 20 millimeter water columns to 65 millimeter water columns, 30 millimeter water columns to 60 millimeter water columns, 35 millimeter water columns to 55 millimeter water columns, or 40 millimeter water columns to 50 millimeter water columns.

[0193] In a particularly preferred embodiment, one or more of the components of the aerosol-generating article are individually surrounded by their own wrapper.

[0194] In one embodiment, the aerosol-forming substrate portion and the mouthpiece element are individually wrapped. The upstream element, the aerosol-forming substrate portion, together with a wrapper surrounding the substrate and a hollow tubular element, is combined with an outer wrapper. Thereafter, they are combined with a downstream filter element having its own wrapper by tipping paper.

[0195] Preferably, at least one of the components of the aerosol-generating article is wrapped in a hydrophobic wrapper.

[0196] The term "hydrophobic" 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 an angle conventionally measured through a liquid, where the liquid / vapor interface meets the solid surface. This quantifies the wettability of the solid surface by the liquid via Young's equation. The hydrophobicity or water contact angle may be determined by utilizing the TAPPI T558 test method, and the results are expressed as the interfacial contact angle and reported in "degrees" and can range from approximately zero to approximately 180 degrees.

[0197] In a preferred embodiment, the hydrophobic wrapper comprises a paper layer having a water contact angle of about 30 degrees or more, preferably about 35 degrees or more, or about 40 degrees or more, or about 45 degrees or more.

[0198] By way of example, the paper layer may include PVOH (polyvinyl alcohol) or silicon. PVOH may be applied to the paper layer as a surface coating, or the paper layer may include a surface treatment containing PVOH or silicon.

[0199] The aerosol-generating article may comprise a tipping wrapper that at least partially surrounds the aerosol-forming substrate portion and at least partially surrounds one or more portions of the aerosol-generating article adjacent to the aerosol-forming substrate portion. One or more adjacent portions may include a front plug.

[0200] The tipping wrapper may be a conventional cigarette paper. The tipping wrapper may 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 may have a thickness of about 65 micrometers and a basis weight of about 45 grams per square meter.

[0201] The tipping wrapper may be thinner than the substrate wrapper. The ratio of the thickness of the tipping 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.

[0202] The aerosol generating article may be provided with ventilation holes. The ventilation holes can promote the nucleation of the aerosol. The ventilation holes can assist in cooling the air flow. The ventilation holes may be provided within the FHAT. The FHAT may include 11 ventilation holes each having a diameter of 0.11 millimeters.

[0203] The total draw resistance of the aerosol generating article may be 5 water column millimeters to 200 water column millimeters, preferably 10 water column millimeters to 150 water column millimeters, more preferably 20 water column millimeters to 100 water column millimeters, more preferably 80 water column millimeters to 80 water column millimeters, more preferably 40 water column millimeters to 60 water column millimeters, more preferably 45 water column millimeters to 55 water column millimeters, more preferably about 48 water column millimeters.

[0204] The aerosol generating article may have a cylindrical shape. The aerosol forming substrate portion may have a cylindrical shape.

[0205] The aerosol-generating article may comprise, in order from the proximal end to the distal end of the article, a mouthpiece filter, one or more intermediate elements, an aerosol-forming substrate part, 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 part may be about 11 millimeters. The tipping wrapper may surround only the complete article or a part thereof.

[0206] The aerosol-forming substrate part may include a susceptor. The susceptor may be at least partially surrounded by the aerosol-forming substrate. The susceptor may be completely surrounded by the aerosol-forming substrate. The susceptor may extend substantially along the entire length of the aerosol-forming substrate part. Thereby, when the susceptor is heated, an optimized heat distribution within the aerosol-forming substrate can be provided. The susceptor may include a flat planar portion. The susceptor may be a flat planar susceptor strip. The susceptor may include a metal or an alloy. The susceptor may include aluminum.

[0207] As used herein, the term "flat planar" relates to a substantially cubic shape having a height that is significantly smaller than the width and length. For example, the width and length may each be at least twice the height of the cube. The height of the flat planar cube may also be referred to as the thickness of the susceptor, or the thickness of the flat planar portion of the susceptor.

[0208] The susceptor element may generally have a thickness of from 0.01 millimeters to 2 millimeters, such as from 0.5 millimeters to 2 millimeters. In some embodiments, the susceptor element preferably has a thickness of from 10 micrometers to 500 micrometers, more preferably from 10 micrometers to 100 micrometers.

[0209] The susceptor may have a thickness of from about 35 micrometers to about 85 micrometers. The susceptor may have a thickness of from about 45 micrometers to about 75 micrometers. The susceptor may have a thickness of from about 55 micrometers to about 65 micrometers.

[0210] The susceptor may be an elongated susceptor disposed substantially in the longitudinal direction within the aerosol-forming substrate portion.

[0211] When used to describe the 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.

[0212] The susceptor may be disposed substantially in the longitudinal direction within the aerosol-forming substrate portion. This means that the length dimension of the elongated susceptor is disposed substantially 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 the radial center position within the aerosol-forming substrate portion and extend along the longitudinal axis of the aerosol-forming substrate portion.

[0213] The susceptor may be in the form of a pin, rod, strip, or blade.

[0214] The susceptor may have a length of from about 5 millimeters to about 15 millimeters, for example, from about 6 millimeters to about 12 millimeters, more preferably from about 8 millimeters to about 10 millimeters. The susceptor may have a length of about 11 millimeters.

[0215] 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 about 6 millimeters or less.

[0216] The elongated susceptor element preferably has a length that is the same as 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, 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%, still more preferably 85% to 95% of the length of the aerosol-forming substrate portion in which it is incorporated.

[0217] When the susceptor has a constant cross-section, for example a circular cross-section, the susceptor may have a width or diameter of from about 1 millimeter to about 5 millimeters.

[0218] When the susceptor has the form of a strip or blade, the strip or blade may preferably have a rectangular cross-section with a width of from about 2 millimeters to about 8 millimeters, more preferably from about 3 millimeters to about 6 millimeters. The susceptor in the form of a blade strip may have a width of about 4 millimeters.

[0219] The elongated susceptor may have a thickness of from about 57 micrometers to about 63 micrometers. Even more preferably, the elongated susceptor may have a thickness of from about 58 micrometers to about 62 micrometers. Most preferably, the elongated susceptor has a thickness of about 60 micrometers.

[0220] The draw resistance of the aerosol-forming substrate portion is from 0.1 millimeter of water column to 200 millimeters of water column, preferably from 1 millimeter of water column to 100 millimeters of water column, more preferably from 5 millimeters of water column to 40 millimeters of water column, still more preferably from 10 millimeters of water column to 30 millimeters of water column, still more preferably from 17 millimeters of water column to 29 millimeters of water column, preferably from 20 millimeters of water column to 26 millimeters of water column, more preferably about 23 millimeters of water column. The draw resistance of the aerosol-forming substrate portion may be 18 millimeters of water column or more. The draw resistance of the aerosol-forming substrate portion may be 23 millimeters of water column or more.

[0221] Having a low draw resistance of the aerosol-forming substrate portion, for example less than 10 millimeters of water column, may mean that the interaction between the air flow and the aerosol-forming substrate is slight, and as a result, the aerosolization is slight. Having a high draw 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 influence on the overall draw resistance of the aerosol-generating article. The draw resistance of the aerosol-forming substrate portion may vary to some extent from article to article due to manufacturing tolerances. By reducing the influence of the aerosol-forming substrate portion on the overall draw resistance of the aerosol-generating article, a more consistent draw resistance can be obtained between different articles.

[0222] The draw resistance of the aerosol-forming substrate portion per millimeter length of the aerosol-forming substrate portion is from 0.1 millimeter of water column to 20 millimeters of water column, preferably from 0.2 millimeter of water column to 10 millimeters of water column, more preferably from 1 millimeter of water column to 5 millimeters of water column, still more preferably from 1.7 millimeters of water column to 2.5 millimeters of water column, still more preferably from 1.9 millimeters of water column to 2.3 millimeters of water column. The draw resistance of the aerosol-forming substrate portion per millimeter length along the major axis direction of the aerosol-generating article may be about 2.1 millimeters of water column.

[0223] The total length of the aerosol-forming substrate portion may be 1 millimeter to 30 millimeters, preferably 5 millimeters to 16 millimeters, more preferably 9 millimeters to 13 millimeters, and even more preferably 10 millimeters to 12 millimeters, along the axis in the longitudinal direction of the aerosol-generating article. The total length of the aerosol-forming substrate portion may be 11 millimeters or less along the axis in the longitudinal direction of the aerosol-generating article.

[0224] The total length of the aerosol-generating article may be 10 millimeters to 150 millimeters, preferably 20 millimeters to 1000 millimeters, more preferably 30 millimeters to 80 millimeters, even more preferably 40 millimeters to 50 millimeters, even more preferably 43 millimeters to 47 millimeters, and even more preferably about 45 millimeters. The length of the aerosol-forming substrate along the longitudinal axis of the article may be 22% to 26% of the total length of the aerosol-generating article, preferably about 24% of the total length of the aerosol-generating article.

[0225] The ratio of the total length of the aerosol-forming substrate portion to the total length of the aerosol-generating article may be at least 0.20. Preferably, the ratio of the total length of the aerosol-forming substrate portion to the total length of the aerosol-generating article is at least 0.25. More preferably, the ratio of the total length of the aerosol-forming substrate portion to the total length of the aerosol-generating article is at least 0.30.

[0226] Preferably, the ratio of the total length of the aerosol-forming substrate portion to the total length of the aerosol-generating article is 0.60 or less. Preferably, the ratio of the total length of the aerosol-forming substrate portion to the total length of the aerosol-generating article is 0.55 or less. More preferably, the ratio of the total length of the aerosol-forming substrate portion to the total length of the aerosol-generating article is 0.50 or less.

[0227] In some embodiments, the ratio of the total length of the aerosol-forming substrate portion to the total length of the aerosol-generating article is from 0.20 to 0.60, preferably from 0.20 to 0.55, more preferably from 0.20 to 0.50. In other embodiments, the ratio of the total length of the aerosol-forming substrate portion to the total length of the aerosol-generating article is from 0.25 to 0.60, preferably from 0.25 to 0.55, more preferably from 0.25 to 0.50. In further embodiments, the ratio of the total length of the aerosol-forming substrate portion to the total length of the aerosol-generating article is from 0.30 to 0.60, preferably from 0.30 to 0.55, more preferably from 0.30 to 0.50.

[0228] As used herein, the terms "external diameter" and "outer diameter" of an aerosol-generating article or a component thereof can be calculated as the average of a plurality of measurements of the diameter of the aerosol-generating article or a component thereof taken at different positions along the length of the aerosol-generating article or a component thereof.

[0229] 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.

[0230] 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.

[0231] 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.

[0232] The total density of the aerosol-forming substrate portion is greater than 0.71 milligrams per cubic millimeter. The total density of the aerosol-forming substrate portion may be 0.715 milligrams or more per cubic millimeter. The total density of the aerosol-forming substrate portion may be 0.720 milligrams or more per cubic millimeter. The total density of the aerosol-forming substrate portion may be approximately 0.725 milligrams per cubic millimeter.

[0233] For example, the substrate wrapper may enclose a cylindrical volume with 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. Then, the total density of the aerosol-forming substrate portion corresponds to 287.2 milligrams divided by 396 cubic millimeters, i.e., 0.725 milligrams per cubic millimeter.

[0234] The total density of the aerosol-generating article at the longitudinal position of the aerosol-forming substrate portion, taking into account the mass and volume of the substrate wrapper and any one or more additional wrappers surrounding the substrate wrapper, may be approximately 0.66 milligrams per cubic millimeter.

[0235] The ratio of the total density of the aerosol-forming substrate portion divided by the total density of the aerosol-generating article at the longitudinal position of the aerosol-forming substrate portion may be greater than 1.0, preferably greater than 1.05, and more preferably 1.09 or more.

[0236] At least 70 volume percent, preferably at least 75 volume percent, and more preferably at least approximately 79 volume percent of the internal volume of the aerosol-forming substrate portion may be filled with the aerosol-forming substrate and optionally one or more susceptor elements.

[0237] Less than 30 volume percent, preferably less than 25 volume percent, more preferably less than about 21 volume percent of the internal volume of the aerosol-forming substrate portion may be empty.

[0238] The total mass of the aerosol-forming substrate within 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 within the aerosol-forming substrate portion may be from 10 milligrams to 3000 milligrams, preferably from 50 milligrams to 1000 milligrams, more preferably from 100 milligrams to 500 milligrams, more preferably from 200 milligrams to 400 milligrams, more preferably from 250 milligrams to 350 milligrams, more preferably from 260 milligrams to 270 milligrams, more preferably from 263 milligrams to 269 milligrams.

[0239] The aerosol-forming substrate portion may include an aerosol-forming substrate and a susceptor. The total mass of the susceptor material within the aerosol-forming substrate portion may be from 1 milligram to 100 milligrams, preferably from 5 milligrams to 50 milligrams, more preferably from 10 milligrams to 40 milligrams, more preferably from 15 milligrams to 25 milligrams, more preferably from 20 milligrams to 23 milligrams, more preferably from 20.5 milligrams to 21.7 milligrams.

[0240] The aerosol-forming substrate portion may include an aerosol-forming substrate and a susceptor. The total mass of the susceptor material within the aerosol-forming substrate portion may be from 20.5 milligrams to 21.7 milligrams. The total mass of the aerosol-forming substrate within the aerosol-forming substrate portion may be from 263 milligrams to 269 milligrams.

[0241] The density of the aerosol-forming substrate may be greater than 800 kilograms per cubic meter, preferably greater than 825 kilograms per cubic meter, and more preferably about 842 kilograms per cubic meter.

[0242] The aerosol-forming substrate may be provided in the form of a sheet. The sheets of the aerosol-forming substrate may aggregate upon insertion into the aerosol-forming substrate portion. The density of the sheet of the aerosol-forming substrate may be determined by dividing the basis weight of the sheet by the thickness of the sheet before aggregating the sheet.

[0243] The aerosol-forming substrate may be provided in the form of an assembly of sheets of homogenized tobacco material.

[0244] The sheets 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, more preferably about 192 grams per square meter.

[0245] The sheets of homogenized tobacco material may have a thickness of more than 215 micrometers, preferably more than 220 micrometers, more preferably about 228 micrometers.

[0246] The sheets of homogenized tobacco material may be cast sheets. The homogenized tobacco material may contain tobacco particles having an average particle size (D95) of more than 50 micrometers, preferably more than 50 micrometers to 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 casting 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 indicate the volume-based median of the particle size distribution and is the value of the particle diameter at 95% of the cumulative distribution. The particle size of the particles can be analyzed by laser diffraction.

[0247] The aerosol-forming substrate may comprise a tobacco material, a binder of from about 1 percent to about 5 percent on a dry weight basis, and glycerin of from about 10 percent to about 30 percent.

[0248] 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 from about 3 millimeters to about 10 millimeters, preferably from about 6 millimeters to about 8 millimeters, more preferably from about 6.5 millimeters to about 7.5 millimeters, more preferably from about 6.6 millimeters to about 7.0 millimeters, more preferably from about 6.7 millimeters to about 6.9 millimeters, more preferably from about 6.75 millimeters to about 6.85 millimeters. The cylindrical shape of the aerosol-forming substrate portion may have a diameter within the range of from about 6.8 millimeters to about 7.1 millimeters, or from about 6.8 millimeters to about 7.0 millimeters.

[0249] The present invention further relates to a package comprising a plurality of aerosol-generating articles, wherein each aerosol-generating article within the package is the aerosol-generating article described herein.

[0250] The present invention further relates to an aerosol generation system comprising an aerosol generating article as described herein and an aerosol generator. The aerosol generator may comprise a heating chamber configured to at least partially insert the aerosol generating article into the heating chamber. The aerosol generator may comprise an internal heating element disposed to be inserted into the aerosol generating article when the aerosol generating article is at least partially inserted into the heating chamber. The aerosol generator may comprise an inductor coil. The inductor coil may at least partially surround the heating chamber. The inductor coil may be disposed to coaxially surround the heating chamber. The inductor coil may be disposed to inductively heat a susceptor element. The susceptor element may be part of the internal heating element of the aerosol generator. The susceptor element may be part of the aerosol generating article. The inductor coil may be disposed to inductively heat the susceptor of the aerosol generating article when the aerosol generating article is at least partially inserted into the heating chamber.

[0251] As used herein, the term "aerosol-forming substrate" refers to a substrate having the ability to release volatile compounds capable of forming an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. The aerosol-forming substrate may be in solid form or in liquid form. The aerosol-forming substrate may be solid or liquid, or may comprise both solid and liquid components. The aerosol-forming substrate may be part of the aerosol generating article. The terms "aerosol" and "vapor" are used interchangeably.

[0252] The aerosol-forming substrate may comprise one or more of tobacco, nicotine, an aerosol generating film, a gel composition, and a flavoring agent. The aerosol-forming substrate may comprise a homogenized tobacco material such as a cast leaf, an aerosol generating film, and a gel composition.

[0253] The aerosol-forming substrate may comprise one or more aerosol formers. The aerosol former can be any suitable known compound or mixture of compounds that promotes the formation of a dense and stable aerosol during use. The aerosol former can promote the aerosol being substantially resistant to thermal decomposition at the temperatures typically applied during use of the aerosol-generating article. Suitable aerosol formers are, for example, polyhydric alcohols (such as triethylene glycol, 1,3-butanediol, propylene glycol, glycerol, etc.), esters of polyhydric alcohols (such as glycerol mono-, di-, or triacetate, etc.), aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate, dimethyl tetradecanedioate, etc.), and combinations thereof. It is preferred that the one or more aerosol formers comprise one or both of glycerol and propylene glycol. The one or more aerosol formers can consist of one or both of glycerol and propylene glycol. The aerosol-forming substrate preferably contains glycerol. The terms "glycerin" and "glycerol" are used synonymously herein.

[0254] The aerosol-forming substrate may contain up to 80 weight percent of the aerosol former, based on the dry weight of the aerosol-forming substrate. The aerosol-forming substrate may contain up to 60 weight percent of the aerosol former, based on the dry weight of the aerosol-forming substrate. The aerosol-forming substrate may contain up to 40 weight percent of the aerosol former, based on the dry weight of the aerosol-forming substrate. The aerosol-forming substrate may contain up to 20 weight percent, or up 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 an aerosol-forming substance in an amount of from 5 wt% to 80 wt%, or from 5 wt% to 60 wt%, or from 5 wt% to 40 wt%, or from 5 wt% to 20 wt%, or from 5 wt% to 15 wt%, or from 7 wt% to 80 wt%, or from 7 wt% to 60 wt%, or from 7 wt% to 40 wt%, or from 7 wt% to 20 wt%, or from 7 wt% to 15 wt%, or from 10 wt% to 80 wt%, or from 10 wt% to 60 wt%, or from 10 wt% to 40 wt%, or from 10 wt% to 20 wt%, or from 10 wt% to 15 wt% based on the dry weight of the aerosol-forming substrate.

[0256] The aerosol-forming substrate may include tobacco material. The aerosol-forming substrate may include shredded tobacco material. For example, the shredded tobacco material may be in the form of cut filler, as will be described in more detail below. Alternatively, the shredded tobacco material may be in the form of a sheet of homogenized tobacco material that has been cut. Suitable homogenized tobacco materials for use in the present invention are described below.

[0257] In the context of this specification, the term "cut filler" is used to describe a blend of finely cut plant material, such as tobacco plant material, specifically including one or more of the lamina of the leaf, processed stems and veins, and homogenized plant material.

[0258] The cut filler may also include other cuttings, filler tobacco, or casing.

[0259] 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 clove. Most preferably, the plant material is tobacco. However, it is preferred that the present invention is equally applicable to other plant materials having the ability to release substances that can form an aerosol upon heating.

[0260] The cut filler preferably comprises tobacco plant material including one or more leaf blades of bright tobacco, dark tobacco, aromatic tobacco, and filler tobacco. For the purposes of the present invention, the term "tobacco" describes any plant of the Nicotiana genus.

[0261] The cut filler suitable for use in the present invention may generally be similar to the cut fillers used in conventional smoking articles. The cut width of the cut filler may preferably be from 0.3 millimeters to 2.0 millimeters, or from 0.5 millimeters to 1.2 millimeters, or from 0.6 millimeters to 0.9 millimeters.

[0262] Preferably, the strands have a length of about 10 millimeters to about 40 millimeters, and then the strands are arranged to form an aerosol-forming substrate portion.

[0263] In a preferred embodiment, the weight of the cut filler is from 80 milligrams to 400 milligrams, preferably from 120 milligrams to 250 milligrams, and more preferably from 150 milligrams to 200 milligrams. This amount of cut filler can typically provide sufficient material for aerosol formation.

[0264] The cut filler is preferably immersed in the aerosol former. The immersion of the cut filler can be carried out by spraying or other suitable application methods. The aerosol former can be added to the blend during the preparation of the cut filler. For example, the aerosol former may be directly applied to the blend in the direct conditioning casing cylinder (DCCC). Conventional machinery can be used to add the aerosol former to the cut filler. Suitable aerosol formers may be those described herein. The aerosol former preferably contains one or both of glycerin and propylene glycol. The aerosol former may consist of glycerol, or propylene glycol, or a combination of glycerol and propylene glycol.

[0265] The aerosol forming substrate may comprise a homogenized plant material, preferably a homogenized tobacco material.

[0266] As used herein, the term "homogenized plant material" encompasses any plant material formed by the aggregation of plant particles. For example, a sheet or web of homogenized tobacco material for the aerosol forming substrate of the present invention can be formed by aggregating the particles of plant material obtained by grinding, pulverizing, or finely crushing the plant material. The homogenized plant material may be produced by casting, extrusion, papermaking processes, or any other suitable process known in the art. The homogenized plant material can be provided in any suitable form.

[0267] In some embodiments, the homogenized plant material may be in the form of one or more sheets. As used herein with respect to the present invention, the term "sheet" describes a thin, layer-like element having a width and length that are considerably larger than its thickness.

[0268] The homogenized plant material may be in the form of a plurality of pellets or granules.

[0269] The homogenized plant material may be in the form of a plurality of strands, flakes, 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 flakes, fragments, and any other homogenized plant material having similar forms. Strands of the homogenized plant material may be formed from a sheet of the homogenized plant material, for example, by cutting or shredding, or by other means, such as an extrusion process.

[0270] As described above, when the homogenized plant material is in the form of one or more sheets, the sheets may be manufactured by a casting process. Alternatively, the sheets of the homogenized plant material may be manufactured by a papermaking process.

[0271] 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. The individual thickness refers to the thickness of an individual sheet, and the combined thickness refers to the total thickness of all the sheets that make up the aerosol-forming substrate.

[0272] One or more sheets as described herein may each individually have a basis weight of from 100 grams per square meter to 600 grams per square meter.

[0273] 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.

[0274] One or more sheets as described herein may be subjected to one or more of crimping, folding, gathering, or pleating.

[0275] 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, or about 4 millimeters, or about 3 millimeters, or about 2 millimeters or less. The length of the strands may be longer than about 5 millimeters, may be about 5 millimeters to about 15 millimeters, may be about 8 millimeters to about 12 millimeters, or may be about 12 millimeters. The strands preferably have substantially the same length as each other.

[0276] The homogenized plant material may comprise, on a dry weight basis, from 2.5 weight percent to 95 weight percent plant particles, or from 5 weight percent to 90 weight percent plant particles, or from 10 weight percent to 80 weight percent plant particles, or from 15 weight percent to 70 weight percent plant particles, or from 20 weight percent to 60 weight percent plant particles, or from 30 weight percent to 50 weight percent plant particles.

[0277] In certain embodiments of the invention, the homogenized plant material is a homogenized tobacco material comprising tobacco particles. Sheets of the homogenized tobacco material used in such embodiments of the invention may have a tobacco content of at least about 40 weight percent, more preferably at least about 50 weight percent, more preferably at least about 70 weight percent, and most preferably at least about 90 weight percent, on a dry weight basis.

[0278] Regarding the present invention, the term "tobacco particle" refers to particles of any plant member of the Nicotiana species. The term "tobacco particle" includes ground or powdered tobacco leaf laminas, ground or powdered tobacco leaf stems, tobacco dust, tobacco fines, and other particulate tobacco by-products formed during the processing, handling, and shipping of tobacco. In a preferred embodiment, the tobacco particles are substantially all derived from tobacco leaf laminas. In contrast, isolated nicotine and nicotine salts are compounds derived from tobacco but are not considered tobacco particles for the purposes of the present invention and are not included in the proportion of particulate plant material.

[0279] In a preferred embodiment, the aerosol-forming substrate comprises strands of homogenized tobacco material, and the weight of the strands of homogenized tobacco material is from 50 milligrams to 2000 milligrams, preferably from 80 milligrams to 400 milligrams, more preferably from 120 milligrams to 250 milligrams, and even more preferably from 150 milligrams to 200 milligrams. This amount of strands of homogenized tobacco material can typically be sufficient material for the formation of an aerosol.

[0280] The aerosol-forming substrate may be in the form of an aerosol-generating film comprising a cellulose-based film-forming agent, nicotine, and an aerosol-forming body. The aerosol-generating film may further comprise a cellulose-based reinforcing agent. The aerosol-generating film may further contain less than 30 weight percent water.

[0281] As used herein, the term "film" 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, the film may have cohesive and mechanical properties such that it can be separated from the support surface even if obtained by casting a film-forming formulation on the support surface. Alternatively, the film may be disposed on a support or sandwiched between other materials. This can enhance the mechanical stability of the film.

[0282] The aerosol generating film may comprise one or more aerosol formers described herein. Preferably, the aerosol former-containing or glycerin-containing aerosol generating film may have an aerosol former content of at least 5 wt% on a dry weight basis. The aerosol generating film may have an aerosol former content of at least 15 wt% on a dry weight basis. The aerosol generating film may have an aerosol former content of at least 20 wt% on a dry weight basis. The aerosol generating film may have an aerosol former content of at least 30 wt% on a dry weight basis. Preferably, the aerosol generating film has an aerosol former content of at least 40 wt% on a dry weight basis. More preferably, the aerosol generating film has an aerosol former content of at least 45 wt% on a dry weight basis. Even more preferably, the aerosol generating film has an aerosol former content of at least 50 wt% on a dry weight basis.

[0283] Preferably, the aerosol generating film has an aerosol former content of 80 wt% or less on a dry mass basis. More preferably, the aerosol generating film has an aerosol former content of 75 wt% or less on a dry weight basis. Even more preferably, the aerosol generating film has an aerosol former content of 70 wt% or less on a dry weight basis.

[0284] 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, either by itself or in the presence of an auxiliary thickener.

[0285] The cellulose-based film-forming agent is preferably selected from the group consisting of hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), ethylcellulose (EC), hydroxyethyl methylcellulose (HEMC), hydroxyethylcellulose (HEC), hydroxypropylcellulose (HPC), and combinations thereof.

[0286] More preferably, the cellulose-based film-forming agent is selected from the group consisting of hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), ethylcellulose (EC), and combinations thereof.

[0287] In a particularly preferred embodiment, the cellulose-based film-forming agent is HPMC.

[0288] The solid aerosol-generating film may have a cellulose-based film-forming agent content of 10 wt% to 40 wt%, or 15 wt% to 35 wt%, or 20 wt% to 30 wt% on a dry weight basis.

[0289] The aerosol-generating film preferably further comprises a cellulose-based reinforcing agent. The cellulose-based reinforcing agent is preferably selected from the group consisting of cellulose fibers, microcrystalline cellulose (MCC), cellulose powder, and combinations thereof.

[0290] The aerosol-generating film may have a cellulose-based reinforcing agent content of 0.5 wt% to 40 wt%, or 5 wt% to 30 wt%, or 10 wt% to 25 wt% on a dry weight basis.

[0291] The aerosol-generating film may further comprise carboxymethylcellulose, preferably sodium carboxymethylcellulose.

[0292] The aerosol generating film may have a carboxymethyl cellulose content of 1 wt% to 15 wt%, or 2 wt% to 12 wt%, or 4 wt% to 10 wt% on a dry weight basis.

[0293] The aerosol generating film preferably contains nicotine.

[0294] 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 contains a nicotine base or a nicotine salt, the amounts of nicotine recited herein are the amounts of free base nicotine or protonated nicotine, respectively.

[0295] The aerosol generating film may contain natural nicotine or synthetic nicotine.

[0296] The aerosol generating film may contain one or more monobasic nicotine salts.

[0297] 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.

[0298] The aerosol generating film preferably contains at least about 0.5 wt% nicotine on a dry weight basis. More preferably, the aerosol generating film contains at least about 1 wt% nicotine on a dry weight basis. Even more preferably, the aerosol generating film contains at least about 2 wt% nicotine on a dry weight basis. Additionally or alternatively, the aerosol generating film preferably contains less than 10 wt% nicotine on a dry weight basis. More preferably, the aerosol generating film contains less than 8 wt% nicotine on a dry weight basis. Even more preferably, the aerosol generating film contains less than 6 wt% nicotine on a dry weight basis.

[0299] For example, the aerosol generating film may contain 0.5% to 10% by weight of nicotine, or 1% to 8% by weight of nicotine, or 2% to 6% by weight of nicotine on a dry weight basis.

[0300] The aerosol generating film may be an aerosol generating film that is substantially tobacco-free.

[0301] In a preferred embodiment, the aerosol generating film contains an acid. More preferably, the aerosol generating film contains one or more organic acids. Even more preferably, the aerosol generating film contains one or more carboxylic acids. In a particularly preferred embodiment, the acid is lactic acid, benzoic acid, fumaric acid or levulinic acid.

[0302] Preferably, the aerosol generating film contains 0.25% to 3.5% by weight of acid, or 0.5% to 3% by weight of acid, or 1% to 2.5% by weight of acid on a dry weight basis.

[0303] 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, even more preferably about 0.1 millimeter to about 0.5 millimeter. In a particularly preferred embodiment, a layer of the film-forming composition having a thickness of about 50 micrometers to 400 micrometers, more preferably about 100 micrometers to 200 micrometers is formed.

[0304] Optionally, the aerosol generating film may be provided on a suitable carrier element.

[0305] The aerosol-forming substrate may include a gel composition containing nicotine, at least one gelling agent and an aerosol former. Preferably, the gel composition is substantially tobacco-free.

[0306] The preferred weight range of nicotine in the gel composition is the same as that defined above in relation to the aerosol generating film.

[0307] The nicotine composition preferably contains, on a dry weight basis, at least 50 weight percent of an aerosol former, more preferably at least 60 weight percent of an aerosol former, more preferably at least 70 weight percent of an aerosol former. The gel composition may contain up to 80 weight percent of an aerosol former. The aerosol former in the gel composition is preferably glycerol.

[0308] The gel composition preferably contains at least one gelling agent. The gel composition preferably contains a total amount of gelling agent in the range of 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.

[0309] The term "gelling agent" refers to a compound that, when added in an amount of about 0.3 weight percent to a homogeneous mixture of 50 weight percent water / 50 weight percent glycerol, forms a solid medium or support matrix leading to a gel. Examples of gelling agents include, but are not limited to, hydrogen bond cross-linked gelling agents and ion cross-linked gelling agents.

[0310] The term "hydrogen bond cross-linked gelling agent" refers to a gelling agent that forms non-covalent cross-links or physical cross-links via hydrogen bonds.

[0311] The hydrogen bond cross-linked gelling agent may include one or more of galactomannan, gelatin, agarose, or konjac gum, or agar. The hydrogen bond cross-linked gelling agent may preferably contain agar.

[0312] The term "ionic crosslinking gelling agent" refers to a gelling agent that forms non-covalent crosslinking bonds or physical crosslinking bonds through ionic bonds.

[0313] The ionic crosslinking gelling agent may include low acyl gellan, pectin, kappa carrageenan, iota carrageenan or alginate. It is preferable that the ionic crosslinking gelling agent may include low acyl gellan.

[0314] The gelling agent may include one or more biopolymers. The biopolymer may be formed of a polysaccharide.

[0315] Examples of the biopolymer include gellan gum (natural gellan gum, low acyl gellan gum, high acyl gellan gum, low acyl gellan gum is preferable), xanthan gum, alginate (algic acid), agar, guar gum and the like. The composition may preferably contain xanthan gum. The composition may include two biopolymers. The composition may include three biopolymers. The composition may include two biopolymers in substantially equal weights. The composition may include three biopolymers in substantially equal weights.

[0316] The gel composition may further include a thickening agent. The thickening agent combined with the hydrogen bond crosslinking gelling agent and the ionic crosslinking gelling agent surprisingly supports the solid matrix and maintains the gel composition even when the gel composition contains a high level of glycerol.

[0317] The term "thickening agent" refers to a compound that increases the viscosity without causing gel formation and keeps the mixture in a fluid state or remains fluid when uniformly added in an amount of 0.3 weight percent in a mixture of 50 weight percent water / 50 weight percent glycerol at 25°C.

[0318] The gel composition preferably contains a thickener in the range of about 0.2 wt% to about 5 wt%, or about 0.5 wt% to about 3 wt%, or about 0.5 wt% to about 2 wt%, or about 1 wt% to about 2 wt%.

[0319] The thickener may include one or more of xanthan gum, carboxymethyl cellulose, microcrystalline cellulose, methyl cellulose, gum arabic, guar gum, lambda carrageenan, or starch. Preferably, the thickener may contain xanthan gum.

[0320] The gel composition may further contain divalent cations. Preferably, the divalent cations include calcium ions such as calcium lactate in the solution. Divalent cations (such as calcium ions) can assist in the gel formation of a composition containing a gelling agent such as an ionic cross-linking gelling agent. The ionic effect may assist in gel formation. The divalent cations may be present in the gel composition in the range of about 0.1 to about 1 wt%, or about 0.5 wt%.

[0321] The gel composition may further contain an acid. The acid may contain a carboxylic acid. The carboxylic acid may contain a ketone group. Preferably, the carboxylic acid may contain a ketone group having less than about 10 carbon atoms, or less than about 6 carbon atoms or less than about 4 carbon atoms, such as levulinic acid or lactic acid. Preferably, this carboxylic acid has three carbon atoms (such as lactic acid).

[0322] The gel composition preferably contains some water. When the composition contains some water, the gel composition is more stable.

[0323] The gel composition preferably contains water in the range of about 8 wt% to about 32 wt%, or about 15 wt% to about 25 wt%, or about 18 wt% to about 22 wt%, or about 20 wt%.

[0324] Preferably, when a gel composition is used, the aerosol-forming substrate comprises a porous medium filled with the gel composition. The advantage of the porous medium filled with the gel composition is that the gel composition is retained within the porous medium, which can assist in the manufacture, storage, or transportation of the gel composition. This can help maintain the desired shape of the gel composition, particularly during manufacture, transportation, or use.

[0325] The term "porous" is used herein to refer to a material that provides a plurality of pores or openings that allow air to pass through the material.

[0326] The porous medium may be any suitable porous material that can hold or retain the gel composition. Ideally, the porous medium can allow the gel composition to move therein. In certain embodiments, the porous medium includes natural materials, synthetic, or semi-synthetic, or combinations thereof. In certain embodiments, the porous medium includes sheet materials, foams, or fibers, such as cotton fibers, or combinations thereof. In certain embodiments, the porous medium includes woven fabrics, non-woven fabrics, or extrudates, or combinations thereof. The porous medium preferably includes cotton, paper, viscose, PLA, or cellulose acetate, or combinations thereof. The porous medium preferably includes a sheet material, such as cotton or cellulose acetate. In a particularly preferred embodiment, the porous medium includes a sheet made from cotton fibers.

[0327] The porous medium may be crimped or shredded. The porous medium may be in the form of a sheet, thread, or tubular element.

[0328] The aerosol-forming substrate may contain nicotine. The nicotine-containing aerosol-forming substrate may be a nicotine salt matrix.

[0329] The aerosol-forming substrate preferably comprises a plant material and an aerosol former. The plant material is preferably a plant material containing an alkaloid, more preferably a plant material containing nicotine, and even more preferably a tobacco-containing material.

[0330] The aerosol-forming substrate preferably contains at least 70% by weight of the plant material, more preferably at least 90% by weight of the plant material, based on the dry weight. The aerosol-forming substrate preferably contains less than 95% by weight of the plant material, such as 90 - 95% by weight of the plant material, based on the dry weight.

[0331] The aerosol-forming substrate preferably contains at least 5% by weight of the aerosol former, more preferably at least 10% by weight of the aerosol former, based on the dry weight. The aerosol-forming substrate preferably contains less than 30% by weight of the aerosol former, such as 5 - 30% by weight of the aerosol former, based on the dry weight.

[0332] In some particularly preferred embodiments, the aerosol-forming substrate comprises a plant material and an aerosol former, and the substrate has an aerosol former content of 5 - 30% by weight based on the dry weight. The plant material is preferably a plant material containing an alkaloid, more preferably a plant material containing nicotine, and even more preferably a tobacco-containing material. An alkaloid is a class of natural nitrogen-containing organic compounds. Alkaloids are mainly 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. The preferred alkaloid is nicotine, which may be found in tobacco.

[0333] The aerosol-forming substrate may contain nicotine. The aerosol-forming substrate may contain tobacco, for example, a tobacco-containing material containing volatile tobacco flavor compounds released from the aerosol-forming substrate upon heating. In a preferred embodiment, the aerosol-forming substrate may contain a homogenized tobacco material, such as cast leaf tobacco. The aerosol-forming substrate may contain both solid and liquid components. The aerosol-forming substrate may contain a tobacco-containing material containing volatile tobacco flavor compounds released from the substrate upon heating. The aerosol-forming substrate may contain a non-tobacco material. The aerosol-forming substrate may further contain an aerosol-forming agent. Examples of suitable aerosol-forming agents are glycerin and propylene glycol.

[0334] As used herein, the term "tobacco material" is used to describe any material containing tobacco, including but not limited to tobacco leaves, tobacco veins, tobacco stems, tobacco petioles, tobacco dust, expanded tobacco, reconstituted tobacco material, and homogenized tobacco material.

[0335] As used herein, the term "homogenized tobacco" means a material formed by aggregating 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 mixtures of the foregoing. Reconstituted tobacco can be made by extracting soluble chemicals from the tobacco by-products, processing the remaining tobacco fibers into a sheet, and then reapplying the extracted material in a concentrated form onto the sheet.

[0336] As used herein, the term "cast leaf" refers 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 mixed state) 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. Examples of the casting or cast leaf process are described, for example, in U.S. Patent No. A-5,724,998 for the production of cast leaf tobacco. In the cast leaf process, particulate plant material is mixed with a liquid constituent (typically water) to form a slurry. Other added constituents 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.

[0337] As used herein, the term "flavorant" refers to a composition having sensory stimulating properties that provide a user with a sensory experience, for example, to enhance the flavor of an aerosol. A flavorant can be used, for example, to deliver taste, smell, or both taste and smell to a user when inhaling an aerosol.

[0338] As used herein, the term "aerosol-generating article" refers to an article comprising an aerosol-forming substrate having the ability to release 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.

[0339] 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 that includes an aerosol-forming substrate and a cartridge that includes an 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 comprise an atomizer, such as an electric heater, to heat the aerosol-forming substrate to form an aerosol.

[0340] As used herein, the term "aerosol generating system" refers to a combination of an aerosol generating device and an aerosol-forming substrate thereof. When the aerosol-forming substrate forms part of an aerosol generating article, the aerosol generating system refers to the combination of the aerosol generating device and the aerosol generating article thereof. In an aerosol generating system, the aerosol-forming substrate and the aerosol generating device cooperate to generate an aerosol.

[0341] As used herein, the term "tubular element" is used to mean an elongated element that defines a lumen or an air flow 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 air flow passage that establishes unbroken fluid communication between the upstream end of the tubular element and the downstream end of the tubular element. However, alternative geometric shapes of the tubular element may of course be possible.

[0342] As used herein, the terms "upstream" and "forward," and "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 in which air flows through the aerosol-generating article during use. An aerosol-generating article according to the present invention comprises a proximal end through which an aerosol exits the article during use. The proximal end of the aerosol-generating article may also be referred to as the mouth-end or the downstream end. The mouth-end is downstream of the distal end. The distal end of the aerosol-generating article may also be referred to as the upstream end. Components or portions of components of the aerosol-generating article may be described as being upstream or downstream of one another based on their relative positions between the proximal end and the distal end of the aerosol-generating article. The forward of a component or portion of a component of the aerosol-generating article is the portion at the end closest to the upstream end of the aerosol-generating article. The rearward of a component or a part of a component of the aerosol-generating article is the portion at the end closest to the downstream end of the aerosol-generating article.

[0343] As used herein, the term "longitudinal direction" refers to the direction corresponding to the major longitudinal axis of the aerosol-generating article, which extends between the upstream end and the downstream end of the aerosol-generating article.

[0344] The term "length" means the dimension of a component of the aerosol-generating article in the longitudinal direction. For example, it may be used to mean the dimension of a rod or an elongated tubular element in the longitudinal direction.

[0345] As used herein in connection with the present invention, the term "transverse direction" is used to describe a direction perpendicular to the longitudinal direction. Unless otherwise specified, the "cross-section" of an aerosol-generating article or a component of an aerosol-generating article refers to a cross-section in the transverse direction.

[0346] As used herein, the term "proximal" refers to the user end or the mouth-end of the aerosol-generating article, and the term "distal" refers to the end opposite the proximal end.

[0347] The components of the aerosol-generating article according to the present invention may be described as being upstream or downstream of each other based on their relative positions between the proximal end and the distal end of the aerosol-generating article.

[0348] The aerosol-generating article may comprise one or more susceptor elements. The one or more susceptor elements may be included within the aerosol-forming substrate portion. For example, one or more elongate susceptor elements may be disposed substantially longitudinally within the aerosol-forming substrate portion and be in thermal contact with the aerosol-forming substrate.

[0349] As used herein, "susceptor" or "susceptor element" means an element that heats when subjected to an alternating magnetic field. This may be the result of eddy currents induced within the susceptor element, hysteresis losses, or both eddy currents and hysteresis losses. In use, the susceptor element is positioned in thermal contact with, or in thermal proximity to, the aerosol-forming substrate received within the aerosol-generating device or cartridge. In this way, the aerosol-forming substrate is heated by the susceptor, thereby forming an aerosol.

[0350] The susceptor element may be formed from any material capable of inductively heating the aerosol-forming substrate to a temperature sufficient to generate an aerosol therefrom. Preferred susceptor elements include metal or carbon.

[0351] Preferred susceptor elements may include, or consist of, ferromagnetic materials such as, for example, ferromagnetic alloys, ferrite iron, or ferromagnetic steel, or stainless steel. Suitable susceptor elements may be, or include, aluminum.

[0352] A suitable susceptor element may comprise a non-metallic core with a metal layer, such as a metal strip formed on the surface of a ceramic core. The susceptor element may have a protective outer layer, such as a protective ceramic layer or a protective glass layer, enclosing the susceptor element. The susceptor element may comprise a protective coating formed of glass, ceramic, or an inert metal, formed over the core of the susceptor element material.

[0353] The susceptor element may be disposed in thermal contact with the aerosol-forming substrate of the aerosol-forming substrate portion of the aerosol-generating article in which the susceptor element is incorporated. Thus, when the temperature of the susceptor element increases, the aerosol-forming substrate is heated and an aerosol is formed. The susceptor element is preferably disposed in physical direct contact with the aerosol-forming substrate, for example, within the aerosol-forming substrate.

[0354] 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 within the heating chamber.

[0355] The aerosol-generating device has a distal end and a mouth-end. The aerosol-generating device may comprise a body or a housing. The body or housing of the aerosol-generating device may define a device cavity for removably receiving the aerosol-generating article at the mouth-end of the device.

[0356] The device cavity may be referred to as the heating chamber of the aerosol-generating device. The device cavity may extend between the distal end and the mouth-side (or proximal) end. The distal end of the device cavity may be a closed end, and the mouth-side (or proximal) end of the device cavity may be an open end. The aerosol-generating article may be inserted into the device cavity or the heating chamber via the open end of the device cavity. The device cavity may be cylindrical in shape to conform to the same shape of the aerosol-generating article.

[0357] The expression "received therein" may refer to the fact that a component or element is received, either fully or partially, within another component or element. For example, the expression "the aerosol-generating article is received within the device cavity" refers to the aerosol-generating article being received, either fully or partially, within the cavity of the aerosol-generating device. When the aerosol-generating article is received within the device cavity, the aerosol-generating article may abut against 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.

[0358] The length of the device cavity may be 15 millimeters to 80 millimeters, or 20 millimeters to 70 millimeters, or 25 millimeters to 60 millimeters, or 25 millimeters to 50 millimeters.

[0359] The length of the device cavity (or the 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 the aerosol-generating article is received with the 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 the aerosol-generating article is received with the aerosol-generating device, at least 80 percent of the length of the aerosol-forming substrate portion is inserted or received within the device cavity. Even more preferably, the length of the device cavity is such that when the aerosol-generating article is received with the aerosol-generating device, at least 90 percent of the length of the aerosol-forming substrate portion is inserted or received within the device cavity. Thereby, the length of the aerosol-forming substrate portion along which the aerosol-forming substrate can be heated during use is maximized, thereby optimizing the generation of aerosol from the aerosol-forming substrate and reducing tobacco waste.

[0360] The length of the device cavity may be such that when the aerosol-generating article is received within the device cavity, a downstream section or a portion thereof is configured to protrude from the device cavity. The length of the device cavity may be such that when the aerosol-generating article is received within the device cavity, a portion of the downstream section (such as a hollow tubular cooling element or a downstream filter segment) is configured to protrude from the device cavity. The length of the device cavity may be such that when the aerosol-generating article is received within the device cavity, a portion of the downstream section (such as a hollow tubular cooling element or a downstream filter segment) is configured to be received within the device cavity.

[0361] 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.

[0362] The diameter of the device cavity may be from 4 millimeters to 10 millimeters. The diameter of the device cavity may be from 5 millimeters to 9 millimeters. The diameter of the device cavity may be from 6 millimeters to 8 millimeters. The diameter of the device cavity may be from 6 millimeters to 7 millimeters.

[0363] The diameter of the device cavity may be substantially the same as or larger than the diameter of the aerosol-generating article. The diameter of the device cavity may be the same as the diameter of the aerosol-generating article in order to establish a tight fit therewith.

[0364] The device cavity can be configured to establish a tight fit with the aerosol-generating article received within the device cavity. The tight fit can refer to a slip fit. The aerosol-generating device can comprise a peripheral wall. Such a peripheral wall can define the device cavity or the heating chamber. The peripheral wall defining the device cavity can be configured to engage in a tight fit with the aerosol-generating article received within the device cavity such that there is substantially no gap or empty space between the peripheral wall defining the device cavity and the aerosol-generating article when received within the device.

[0365] Such an airtight fit can establish an airtight fit or configuration between the device cavity and the aerosol-generating article received therein.

[0366] In such an airtight configuration, there will be substantially no gap or empty space between the peripheral wall defining the device cavity and the aerosol-generating article through which air can pass and flow.

[0367] The 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.

[0368] The aerosol-generating device may comprise an airflow channeling extending between a channel inlet and a channel outlet. The airflow channel can be configured to establish a 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 can 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 the aerosol-generating article is received within the device cavity, the airflow channel can be configured to provide air flowing into the article to deliver the generated aerosol to the user who sucks from the mouth-side end of the article.

[0369] 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 by a combination of both. The airflow channel may be partially defined by the inner surface of the peripheral wall and may be partially defined within the thickness of the peripheral wall. The inner surface of the peripheral wall defines the periphery of the device cavity.

[0370] The airflow channel of the aerosol generating device may extend from an inlet located at the mouth-side end or proximal end of the aerosol generating device to an outlet located away from the mouth-side end of the device. The airflow channel may extend along a direction parallel to the longitudinal axis of the aerosol generating device.

[0371] The heater may be of any suitable type. In the present invention, the heater is preferably an external heater.

[0372] The heater is preferably located around the heating chamber or its periphery.

[0373] The heater preferably 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.

[0374] In some embodiments, the heater is arranged to heat the outer surface of the aerosol-forming substrate portion.

[0375] 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.

[0376] The heater may be disposed within the device cavity or the heating chamber.

[0377] The heater may comprise at least one heating element. The at least one heating element can be any suitable type of heating element. In some embodiments, the device comprises only one heating element. In some embodiments, the device comprises a plurality of heating elements.

[0378] Suitable materials for forming at least one resistive heating element include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilicide, etc.), carbon, graphite, metals, metal alloys, and composite materials made of ceramic materials and metal materials. Such composite materials may include doped ceramics 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-containing, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, and iron-containing alloys, as well as nickel, iron, cobalt, stainless steel-based superalloys, Timetal®, and iron-manganese-aluminum-based alloys.

[0379] In some embodiments, the at least one resistive heating element includes one or more stamped portions of an electrically resistive material (such as stainless steel). Alternatively, the at least one resistive heating element may include a heating wire or filament (e.g., Ni-Cr (nickel-chromium), platinum, tungsten, or alloy wire).

[0380] In some embodiments, the at least one heating element includes an electrically insulated substrate, and the at least one resistive heating element is provided on the electrically insulated substrate.

[0381] The electrically insulated substrate can comprise any suitable material. For example, the electrically insulated substrate can comprise one or more of paper, glass, ceramic, anodized metal, coated metal, and polyimide. The ceramic can comprise mica, alumina (Al2O3) or zirconia (ZrO2). The electrically insulated substrate preferably has a thermal conductivity of about 40 watts / meter kelvin or less, preferably about 20 watts / meter kelvin or less, and ideally about 2 watts / meter kelvin or less.

[0382] The heater can comprise a heating element comprising a rigid electrically insulated substrate having one or more conductive tracks or wires arranged on its surface. Depending on the size and shape of the electrically insulated substrate, it may be possible to insert the heater directly into the aerosol-forming substrate. If the electrically insulated substrate is not sufficiently rigid, the heating element may include further reinforcing means. Current can pass through one or more conductive tracks to heat the heating element and the aerosol-forming substrate.

[0383] In some embodiments, the heater comprises an induction heating arrangement. The induction heating device can comprise an inductor coil and a power source configured to provide a high-frequency oscillating current to the inductor coil. As used herein, a high-frequency oscillating current means an oscillating current having a frequency of about 500 kHz to about 30 MHz. Advantageously, the heater can comprise a DC / AC inverter for converting a DC current supplied by a DC power source into an AC current. The inductor coil can be arranged to generate a high-frequency oscillating electromagnetic field when receiving the high-frequency oscillating current from the power source. The inductor coil can be arranged to generate a high-frequency oscillating electromagnetic field within the device cavity. In some embodiments, the inductor coil can substantially surround the device cavity. The inductor coil can extend at least partially along the length of the device cavity.

[0384] The heater may include an induction heating element. The induction heating element may be a susceptor element. The susceptor element can be arranged such that when the 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 within the susceptor element to heat the susceptor element. In these embodiments, it is preferred that the aerosol generating device has the ability to generate an oscillating electromagnetic field having a magnetic field strength (strength of the H-field) of from 1 to 5 kiloamperes per meter (kA / m), preferably from 2 to 3 kA / m, for example about 2.5 kA / m. An electrically operated aerosol generating device preferably has the ability to generate an oscillating electromagnetic field having a frequency of from 1 to 30 MHz, for example from 1 to 10 MHz, for example from 5 to 7 MHz.

[0385] In these embodiments, the susceptor element is preferably positioned in contact with the aerosol forming substrate. In some embodiments, the susceptor element is located within the aerosol generating device. In these embodiments, the susceptor element may be located within the cavity. The aerosol generating device may include only one susceptor element. The aerosol generating device may comprise a plurality of susceptor elements. In some embodiments, the susceptor element is preferably arranged to heat the outer surface of the aerosol forming substrate.

[0386] The susceptor element may comprise any suitable material as described above in relation to susceptor elements incorporated within the aerosol forming substrate portion.

[0387] In some embodiments, the aerosol generating device may comprise at least one resistive heating element and at least one inductive heating element. In some embodiments, the aerosol generating device may comprise a combination of a resistive heating element and an inductive heating element.

[0388] In use, the heater can be controlled to operate within a defined operating temperature range below 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.

[0389] The aerosol generating device may be provided with 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 be required to be rechargeable and may have a capacity that allows for sufficient energy storage for one or more user operations, such as one or more experiences of aerosol generation.

[0390] [Examples] 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 of the features of another example, embodiment, or aspect described herein.

[0391] Example 1: An aerosol generating article, an aerosol forming substrate within an aerosol forming substrate portion, and a substrate wrapper at least partially surrounding the aerosol forming substrate portion, wherein the substrate wrapper has a thickness of 50 micrometers or more, the substrate wrapper includes one or more layers having the same length in the longitudinal direction of the aerosol generating article, and the total density of the aerosol forming substrate portion is more than 0.71 milligrams per cubic millimeter. Example 2: The aerosol generating article according to 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. Example 3: The aerosol generating article according to Example 1 or Example 2, wherein at least one of the one or more layers of the base wrapper has an individual thickness of 50 micrometers or more. Example 4: The aerosol generating article according to Example 3, wherein each of the one or more layers of the base wrapper having the same length has an individual thickness of 50 micrometers or more. Example 5: The aerosol generating article according to any one of Examples 1 to 4, wherein the base wrapper does not extend in the longitudinal direction of the aerosol generating article beyond the longitudinal ends of the aerosol forming substrate portion. Example 6: An aerosol generating article, an aerosol forming substrate within the aerosol forming substrate portion, and a base wrapper at least partially surrounding the aerosol forming substrate portion, wherein the base wrapper has a thickness of 50 micrometers or more, the base wrapper does not extend in the longitudinal direction of the aerosol generating article beyond the ends of the aerosol forming substrate portion, and the total density of the aerosol forming substrate portion is more than 0.71 milligrams per cubic millimeter. Example 7: The aerosol generating article according to any one of Examples 1 to 6, wherein the base 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. Example 8: The aerosol generating article according to Example 7, wherein the base wrapper has a thickness of 140 micrometers to 160 micrometers. Example 9: The aerosol generating article according to any one of Examples 1 to 8, wherein the ratio of the thickness of the base 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. Example 10: An aerosol generating article according to any one of Examples 1 to 9, wherein the density of the base wrapper is 800 kg / m³ or less, preferably 750 kg / m³ or less, more preferably 700 kg / m³ or less, more preferably 650 kg / m³ or less, more preferably 600 kg / m³ or less, more preferably 550 kg / m³ or less, more preferably 500 kg / m³ or less, more preferably 450 kg / m³ or less, more preferably 400 kg / m³ or less, more preferably 350 kg / m³ or less, and more preferably about 320 kg / m³. Example 11: An aerosol generating article according to any one of Examples 1 to 10, wherein the base wrapper has a basis weight of less than 60 g / m². Example 12: An aerosol generating article according to Example 11, wherein the base wrapper has a basis weight of more than 28 g / m² and less than 50 g / m². Example 13: An aerosol generating article according to any one of Examples 1 to 12, wherein the base wrapper has a thickness of more than 145 µm and a density of 400 kg / m³ or less. Example 14: An aerosol generating article according to any one of Examples 1 to 13, wherein the base wrapper is perforated. Example 15: An aerosol generating article according to any one of Examples 1 to 14, wherein the base wrapper is embossed. Example 16: An aerosol generating article according to any one of Examples 1 to 13, wherein the base wrapper has a uniform thickness that does not vary by more than about 30 µm, or more than about 20 µm, or more than about 10 µm, or more than about 5 µm at any point. Example 17: The base wrapper exhibits a wrapper permeability within the range of 4000 to 4800 cholesterol units, preferably 4200 to 4600 cholesterol units, more preferably 4300 to 4500 cholesterol units, and the permeability of the cigarette paper is determined by using the international standard test method ISO 2965:2009, and the result is expressed in cubic centimeters per square centimeter per minute and is referred to as "cholesterol unit", and the aerosol generating article according to any one of Examples 1 to 16. Example 18: The aerosol generating article according to any one of Examples 1 to 17, wherein the base wrapper has a roughness of about 50 Bekk seconds to about 1000 Bekk seconds, preferably about 100 Bekk seconds to about 200 Bekk seconds. Example 19: The aerosol generating article according to any one of Examples 1 to 18, wherein the base wrapper extends in a direction parallel to the long axis direction of the aerosol generating article along the entire length of the aerosol forming base portion. Example 20: The aerosol generating article according to any one of Examples 1 to 19, wherein the base wrapper includes one or more of cardboard, plastic, and metal foil. Example 21: The aerosol generating article according to any one of Examples 1 to 20, wherein the base wrapper includes one or more of cellulose-based materials, such as paper, wood, fabric, natural fibers, and artificial fibers. Example 22: The aerosol generating article according to any one of Examples 1 to 21, wherein the base wrapper includes a paper layer. Example 23: The aerosol generating article according to any one of Examples 1 to 22, wherein the base wrapper includes a laminated sheet, preferably the base wrapper is made of a laminated sheet, and more preferably the laminated sheet is a laminate of a paper layer having an aluminum layer. Example 24: The aerosol generating article according to any one of Examples 1 to 23, wherein the base wrapper is formed from a single continuous sheet, preferably a single paper sheet. Example 25: A base wrapper is a base wrapper system formed from a first individual wrapper sheet and a second individual wrapper sheet. The first individual wrapper sheet includes a first overlapping region formed by overlapping opposing end portions of the first individual wrapper sheet. The second individual wrapper sheet includes a second overlapping region formed by overlapping opposing end portions of the second individual wrapper sheet. The first overlapping region is offset from the second overlapping region by at least about 5 percent, preferably at least about 10 percent, more preferably at least about 15 percent, and more preferably from about 40 percent to about 60 percent around the aerosol-forming substrate portion. An aerosol-generating article according to any one of Examples 1 to 23. 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 millimeters or less. 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 homogenized tobacco material. Example 28: An aerosol-generating article according to 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. Example 29: An aerosol-generating article according to Example 27 or Example 28, wherein the sheet of homogenized tobacco material has a thickness of more than 215 micrometers, preferably more than 220 micrometers, and more preferably about 228 micrometers. Example 30: The sheet of homogenized tobacco material is a cast sheet, and the homogenized tobacco material contains tobacco particles having an average particle size (D95) of more than 50 micrometers, preferably more than 50 micrometers and less than 100 micrometers, more preferably 60 micrometers to 80 micrometers, more preferably 65 micrometers to 75 micrometers, and more preferably about 70 micrometers before the casting process. The aerosol-generating article according to any one of Examples 27 to 29. Example 31: The aerosol-forming substrate contains a tobacco material, a binder of about 1 percent to about 5 percent on a dry weight basis, and glycerin of about 10 percent to about 30 percent. The aerosol-generating article according to any one of Examples 1 to 30. Example 32: 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. The aerosol-generating article according to any one of Examples 1 to 31. Example 33: The aerosol-forming substrate portion includes a susceptor, and preferably, the susceptor is at least partially surrounded by the aerosol-forming substrate. The aerosol-generating article according to any one of Examples 1 to 32. Example 34: The total density of the aerosol-forming substrate portion is 0.715 milligrams or more per cubic millimeter, preferably 0.720 milligrams or more per cubic millimeter, and more preferably about 0.725 milligrams per cubic millimeter. The aerosol-generating article according to any one of Examples 1 to 33. Example 35: At least 70 volume percent, preferably at least 75 volume percent, and more preferably at least about 79 volume percent of the internal volume of the aerosol-forming substrate portion is filled with the aerosol-forming substrate and optionally one or more susceptor elements. The aerosol-generating article according to any one of Examples 1 to 34. Example 36: The total density of the aerosol-forming substrate portion is 0.715 milligrams or more per cubic millimeter, preferably about 0.720 milligrams per cubic millimeter, more preferably about 0.725 milligrams per cubic millimeter, and preferably at least 70 volume percent, preferably at least 75 volume percent, more preferably at least about 79 weight percent of the internal volume of the aerosol-forming substrate portion is filled with the aerosol-forming substrate and optionally one or more susceptor elements, the aerosol-generating article according to any one of Examples 1 to 35. Example 37: The total density of the aerosol-forming substrate portion is 0.720 milligrams or more per cubic millimeter, and at least about 77 volume percent of the internal volume of the aerosol-forming substrate portion is filled with the aerosol-forming substrate and optionally one or more susceptor elements, the aerosol-generating article according to any one of Examples 1 to 36. Example 38: Less than 30 volume percent, preferably less than 25 volume percent, more preferably about 21 volume percent or less of the internal volume of the aerosol-forming substrate portion is empty, the aerosol-generating article according to any one of Examples 1 to 37. Example 39: The total mass of the aerosol-forming substrate is less than 300 milligrams, preferably less than 290 milligrams, more preferably about 266 milligrams, the aerosol-generating article according to any one of Examples 1 to 38. Example 40: The total density of the aerosol-forming substrate portion is 0.715 milligrams per cubic millimeter, preferably 0.720 milligrams per cubic millimeter, more preferably about 0.725 milligrams per cubic millimeter, the total mass of the aerosol-forming substrate is less than 300 milligrams, preferably less than 290 milligrams, more preferably less than 285 milligrams, more preferably less than 280 milligrams, more preferably less than 275 milligrams, more preferably less than 270 milligrams, more preferably about 266 milligrams, the aerosol-generating article according to any one of Examples 1 to 39. Example 41: An aerosol generating article according to any one of Examples 1 to 40, wherein the total density of the aerosol-forming substrate portion is 0.720 mg or more per cubic millimeter, and the total mass of the aerosol-forming substrate is less than 290 mg, preferably less than 280 mg. Example 42: An aerosol generating article according to any one of Examples 1 to 41, wherein the draw resistance of the aerosol-forming substrate portion surrounded by the substrate wrapper is more than 10 mmH₂O, preferably more than 20 mmH₂O, and more preferably about 23 mmH₂O. Example 43: An aerosol generating article according to any one of Examples 1 to 42, wherein the total density of the aerosol-forming substrate portion is 0.715 mg or more per cubic millimeter, preferably 0.720 mg or more per cubic millimeter, and more preferably about 0.725 mg per cubic millimeter, and the draw resistance of the aerosol-forming substrate portion surrounded by the substrate wrapper is more than 10 mmH₂O, preferably more than 20 mmH₂O, and more preferably about 23 mmH₂O. Example 44: An aerosol generating article according to any one of Examples 1 to 43, wherein the total density of the aerosol-forming substrate portion is 0.720 mg or more per cubic millimeter, and the draw resistance of the aerosol-forming substrate portion surrounded by the substrate wrapper is more than 20 mmH₂O. Example 45: An aerosol generating article according to any one of Examples 1 to 44, wherein the draw resistance of the aerosol-forming substrate portion surrounded by the substrate wrapper per millimeter length along the major axis direction of the aerosol generating article is 1.7 mmH₂O to 2.5 mmH₂O, preferably about 1.9 mmH₂O to 2.1 mmH₂O, and more preferably about 2.1 mmH₂O. Example 46: The density of the aerosol-forming substrate is more than 800 kilograms per cubic meter, preferably more than 825 kilograms per cubic meter, more preferably about 842 kilograms per cubic meter, and the aerosol-generating article according to any one of Examples 1 to 45. Example 47: The total density of the aerosol-forming substrate portion is 0.715 milligrams or more per cubic millimeter, preferably 0.720 milligrams or more per cubic millimeter, more preferably about 0.725 milligrams per cubic millimeter, and the density of the aerosol-forming substrate is more than 800 kilograms per cubic meter, preferably more than 825 kilograms per cubic meter, more preferably about 842 kilograms per cubic meter, and the aerosol-generating article according to any one of Examples 1 to 46. Example 48: The total density of the aerosol-forming substrate portion is 0.720 milligrams or more per cubic millimeter, and the density of the aerosol-forming substrate is more than 825 kilograms per cubic meter, preferably 835 kilograms per cubic meter per cubic millimeter, and the aerosol-generating article according to any one of Examples 1 to 47. Example 49: The ratio obtained by dividing the total density of the aerosol-forming substrate portion by the total density of the aerosol-generating article at the position in the major axis direction of the aerosol-forming substrate portion is more than 1.0, preferably more than 1.05, more preferably 1.09 or more, and the aerosol-generating article according to any one of Examples 1 to 48. Example 50: The total density of the aerosol-forming substrate portion is 0.720 milligrams or more per cubic millimeter, and the ratio obtained by dividing the total density of the aerosol-forming substrate portion by the total density of the aerosol-generating article at the position in the major axis direction of the aerosol-forming substrate portion is more than 1.05, preferably 1.09 or more, and the aerosol-generating article according to any one of Examples 1 to 49. Example 51: An aerosol generating system comprising an aerosol generating article according to any one of Examples 1 to 50 and an aerosol generating device comprising a heating chamber configured to at least partially insert the aerosol generating article into the heating chamber.

[0392] Features described with respect to one embodiment may equally apply to other embodiments of the present invention.

[0393] Although only by way of illustration, the present invention will be further described with reference to the accompanying drawings.

[0394] Figure 1a shows an aerosol generating article in cross-section. The aerosol generating article comprises a mouth-side end filter 10 located at the proximal end of the article. The article further comprises a PLA (polylactic acid) plug 12, a hollow acetate tube 14, and an aerosol-forming substrate portion 16 comprising an aerosol-forming substrate, for example an assembly of homogenized tobacco sheets. The total density of the aerosol-forming substrate portion 16 comprising the aerosol-forming substrate is greater than 0.71 milligrams per cubic millimeter. The mouth-side end filter 10, the PLA plug 12, and the hollow acetate tube 14 form a downstream section downstream of the aerosol-forming substrate portion 16. The article is surrounded by an outer wrapper 18, for example a tipping wrapper. A central axis 22 extends centrally along the longitudinal axis direction of the aerosol generating article. The aerosol-forming substrate portion 16 is surrounded by a thick substrate wrapper 24. The substrate wrapper 24 does not extend in a direction parallel to the central axis 22 beyond the longitudinal ends of the aerosol-forming substrate portion 16.

[0395] Figure 1b shows an aerosol generating article in cross-section. The article of Figure 1b is identical to the article of Figure 1a except that the article of Figure 1b further comprises a flat planar susceptor 20. The flat planar susceptor 20 is disposed within the aerosol-forming substrate portion 16 and is surrounded by the aerosol-forming substrate.

[0396] Figure 2a shows the aerosol generating article in cross-section. The article of Figure 2a comprises a mouth-end filter 10, a fine hollow acetate tube 38, a hollow acetate tube 40, an aerosol-forming substrate portion 16 including an aerosol-forming substrate, 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.

[0397] The aerosol-forming substrate portion 16 may include an optional susceptor 20. The total density of the aerosol-forming substrate and, if present, the aerosol-forming substrate portion 16 including the optional susceptor 20 is greater than 0.71 milligrams per cubic millimeter. 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 ventilation holes 46 is provided in the region where the mouthpiece wrapper 44 overlaps the tipping wrapper 18. The ventilation holes 46 may be provided in one or both of the fine hollow acetate tube 38, the mouthpiece wrapper 44, and the tipping wrapper 18. The aerosol-forming substrate portion 16 is surrounded by a thick substrate wrapper 24.

[0398] 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 length of the mouth-end filter 10 is about 12 millimeters, the length of the fine hollow acetate tube 38 is about 9 millimeters, the length of the hollow acetate tube 40 is about 8 millimeters, the length of the aerosol-forming substrate portion 16 is about 11 millimeters, and the length of the front plug 42 is about 5 millimeters.

[0399] Figure 2b shows the aerosol generating article in cross-section. The aerosol generating article of Figure 2b may have an overall length of about 75 millimeters and an outer diameter of about 6.7 millimeters.

[0400] The article of FIG. 2b includes, at the proximal end of the article, a hollow mouthpiece tube 48, e.g., a hollow cylindrical tube made of cellulose acetate. The hollow mouthpiece tube 48 defines an internal cavity that extends entirely from the upstream end of the hollow mouthpiece tube 48 to the downstream end of the mouth-side end filter 10. The internal cavity is substantially empty, and thus allows for a substantially unrestricted airflow along the internal 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 about 6 millimeters, and the outer diameter may be about 6.7 millimeters. The wall thickness of the hollow mouthpiece tube 48 may be about 1 millimeter.

[0401] The article further includes a mouth-side end filter 10. The mouth-side end filter 10 may have a length of about 10 millimeters. The outer diameter of the mouth-side end filter 10 may be about 6.7 millimeters.

[0402] The article further includes 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 water column millimeters. 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. Thus, the thickness of the peripheral wall of the hollow tube 50 can be about 0.25 millimeters.

[0403] The hollow tube 50 may include one or more rows of ventilation holes 46 arranged 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.

[0404] At the distal end, the article comprises an aerosol-forming substrate portion 16 that includes an aerosol-forming substrate. The total density of the aerosol-forming substrate portion 16 that includes the aerosol-forming substrate is greater than 0.71 milligrams per cubic millimeter. The aerosol-forming substrate portion 16 is surrounded by a thick substrate wrapper 24. Further, one or more outer wrappers 18, 44 may be provided that surround at least a portion of the aerosol-generating article. The one or more outer wrappers 18, 44 may also include ventilation holes 46. The outer wrapper 44, if present, may be over a portion of the outer wrapper 18 that is over the hollow tube 50. Thus, the outer wrapper 44 effectively couples the mouth-end filter 10 to the remaining components of the article. The width of the outer wrapper 44 may be about 26 millimeters.

[0405] In one embodiment, the aerosol-generating article of FIG. 2b 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 mouth-end filter 10 has a length of about 10 millimeters, and the length of the hollow mouthpiece tube 48 is about 6 millimeters.

[0406] FIG. 3a shows, in cross-section, an aerosol-generating article that comprises an aerosol-forming substrate portion 16. The total density of the aerosol-forming substrate portion 16 that includes the aerosol-forming substrate is greater than 0.71 milligrams per cubic millimeter. The aerosol-forming substrate portion 16 is surrounded by a thick substrate wrapper 24. The downstream section includes the hollow tube 50 and the mouth-end filter 10. The hollow tube 50 may include one or more rows of ventilation holes 46. The upstream section includes a front plug 42. The front plug 42 may be provided in the form of a cylindrical plug filled with cellulose acetate tow, or in the form of a hollow cylindrical plug of cellulose acetate tow having a wall thickness of about 1 millimeter. Further, one or more outer wrappers 18, 44 may be provided that surround at least a portion of the aerosol-generating article.

[0407] The aerosol-generating article may have an overall length of about 45 millimeters and an outer diameter of 7.2 millimeters. The overall length of the downstream section may be about 20 to 30 millimeters. The length of the mouth-side end filter 10 may be about 7 millimeters. The overall length of the upstream section may be about 5 millimeters.

[0408] Figure 3b shows in cross-section an aerosol-generating article comprising an aerosol-forming substrate portion 16 at its distal end. The total density of the aerosol-forming substrate portion 16, including the aerosol-forming substrate, is greater than 0.71 milligrams per cubic millimeter. The aerosol-forming substrate portion 16 is surrounded by a thick substrate wrapper 24. The downstream section includes a hollow tube 50 and a mouth-side end filter 10. The hollow tube 50 may include one or more rows of ventilation holes 46.

[0409] The aerosol-generating article of Figure 3b may have an overall length of about 45 millimeters and an outer diameter of 7.2 millimeters. The hollow tube 50 may have a length of about 20 to 30 millimeters, an outer diameter of about 7.2 millimeters, and an inner diameter of about 6.7 millimeters. Thus, the thickness of the peripheral wall of the hollow tube 50 is about 0.25 millimeters. The mouth-side end filter 10 may have a length of about 5 to 7 millimeters and an outer diameter of about 7.2 millimeters. The mouth-side end filter 10 may include low-density cellulose acetate filter segments. The RTD of the mouth-side end filter 10 may be about 8 millimeters of water column. The mouth-side end filter 10 may be individually wrapped by 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. An aerosol-generating article, comprising: an aerosol-forming substrate within an aerosol-forming substrate portion; and a substrate wrapper at least partially surrounding the aerosol-forming substrate portion, wherein the substrate wrapper has a thickness of 50 micrometers or more, the substrate wrapper includes one or more layers having the same length in the longitudinal axis direction of the aerosol-generating article, and the total density of the aerosol-forming substrate portion is more than 0.71 milligrams per cubic millimeter.

2. The aerosol-generating article according to claim 1, wherein the substrate wrapper has a thickness of 60 micrometers or more, preferably 100 micrometers or more, more preferably 120 micrometers or more, and even more preferably 140 micrometers or more.

3. The aerosol-generating article according to claim 2, wherein the substrate wrapper has a thickness of 140 to 155 micrometers.

4. The aerosol-generating article according to any one of claims 1 to 3, wherein 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.

5. The aerosol-generating article according to any one of claims 1 to 4, wherein the total density of the aerosol-forming substrate portion is 0.715 milligrams per cubic millimeter or more, preferably 0.720 milligrams per cubic millimeter or more, and more preferably about 0.725 milligrams per cubic millimeter.

6. The aerosol-generating article according to any one of claims 1 to 5, wherein at least 70 volume percent, preferably at least 75 volume percent, and more preferably at least about 79 volume percent of the internal volume of the aerosol-forming substrate portion is filled with the aerosol-forming substrate and optionally one or more susceptor elements.

7. The aerosol-generating article according to any one of claims 1 to 6, wherein less than 30 volume percent, preferably less than 25 volume percent, and more preferably about 21 volume percent or less of the internal volume of the aerosol-forming substrate portion is empty.

8. The total mass of the aerosol-forming substrate is less than 300 milligrams, preferably less than 290 milligrams, and more preferably about 266 milligrams, the aerosol-generating article according to any one of claims 1 to 7.

9. The draw resistance of the aerosol-forming substrate portion surrounded by the substrate wrapper is more than 10 millimeter water columns, preferably more than 20 millimeter water columns, and more preferably about 23 millimeter water columns, the aerosol-generating article according to any one of claims 1 to 8.

10. The draw resistance of the aerosol-forming substrate portion surrounded by the substrate wrapper per millimeter length along the long axis direction of the aerosol-generating article is 1.7 millimeter water columns to 2.5 millimeter water columns, preferably about 1.9 millimeter water columns to 2.1 millimeter water columns, and more preferably about 2.1 millimeter water columns, the aerosol-generating article according to any one of claims 1 to 9.

11. The density of the aerosol-forming substrate is more than 800 kilograms per cubic meter, preferably more than 825 kilograms per cubic meter, and more preferably about 842 kilograms per cubic meter, the aerosol-generating article according to any one of claims 1 to 10.

12. The ratio of dividing the total density of the aerosol-forming substrate portion by the total density of the aerosol-generating article at the position in the long axis direction of the aerosol-forming substrate portion is greater than 1.0, preferably greater than 1.05, and more preferably 1.09 or more, the aerosol-generating article according to any one of claims 1 to 11.

13. The total length of the aerosol-forming substrate portion is 11 millimeters or less, the aerosol-generating article according to any one of claims 1 to 12.

14. The substrate wrapper does not extend in the long axis direction of the aerosol-generating article beyond the end of the aerosol-forming substrate portion, the aerosol-generating article according to any one of claims 1 to 13.

15. An aerosol-generating system comprising the aerosol-generating article according to any one of claims 1 to 14 and the heating chamber configured to insert the aerosol-generating article at least partially into the heating chamber.

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