Aerosol-generating article comprising an upstream element

Abstract

An aerosol generating article (10) comprising an aerosol generating substrate (16) and an upstream element (18) located upstream of the aerosol generating substrate (16), wherein the upstream element (18) comprises a tubular portion (32) defining an inner region of the upstream element (18) and a spiral sheet (34) defining a plurality of channels (36) extending in the longitudinal direction within the inner region, and the spiral sheet (34) has a basis weight of about 100 grams per square meter or less.

Description

Technical Field

[0001] The present invention relates to an aerosol generating article comprising an aerosol generating substrate for generating an inhalable aerosol upon heating. The present invention also relates to an aerosol generating system comprising the aerosol generating article and an aerosol generating device configured to heat the aerosol generating article.

Background Art

[0002] Aerosol generating articles in which an aerosol generating substrate containing an aerosol generating material such as a tobacco-containing material is heated rather than burned are known in the art. One objective of such “heated” aerosol generating articles is to reduce known harmful smoke components of the type generated by the combustion and pyrolytic decomposition of tobacco in conventional cigarettes.

[0003] Typically, in a heated aerosol generating article, the aerosol is generated by the transfer of heat from a heat source to an aerosol generating substrate physically separated from the heat source. In use, volatile compounds are released from the aerosol generating substrate by the transfer of heat from the heat source to the aerosol generating substrate and entrained in the air drawn through the aerosol generating article. As the released compounds cool, they condense to form an aerosol inhaled by the user.

[0004] One well-known type of heated aerosol generating article, commonly referred to as a heat-not-burn tobacco product or a heated tobacco product, comprises a solid aerosol generating substrate containing a tobacco material, which is heated to produce an inhalable aerosol.

[0005] A number of handheld aerosol generating devices configured to heat an aerosol generating substrate of a heated aerosol generating article are known in the art. Such devices include electrically operated aerosol generating devices in which aerosol is generated by heat transfer from one or more electrical heating elements of the aerosol generating device to the aerosol generating substrate of the heated aerosol generating article. Known handheld electrically operated aerosol generating devices typically comprise a battery, control electronics, and one or more electrical heating elements for heating an aerosol generating substrate of a heated aerosol generating article specially designed for use in the aerosol generating device.

[0006] Some known electrically heated aerosol generating devices include an internal heating element configured to be inserted into the aerosol generating substrate of the heated aerosol generating article. For example, International Publication No. WO 2013 / 098410 A2 discloses an aerosol generating system comprising an aerosol generating article and an electrically operated aerosol generating device including a heating element in the form of a blade inserted into the aerosol generating substrate of the aerosol generating article.

[0007] Other known electrically operated aerosol generating devices include one or more external heating elements. For example, International Publication No. WO 2020 / 115151 A1 discloses an aerosol generating system comprising an aerosol generating article and an electrically operated aerosol generating device including an external heating element surrounding the aerosol generating article.

[0008] Electrically operated aerosol generating devices are also known that include an inductor configured to inductively heat an aerosol generating substrate of a heated aerosol generating article. For example, WO 2015 / 176898 A1 discloses an aerosol generating system comprising an aerosol generating article including an elongated susceptor in thermal contact with an aerosol generating substrate and an electrically operated aerosol generating device having an inductor for heating the aerosol generating substrate. In use, the varying or alternating electromagnetic field generated by the inductor induces eddy currents in the susceptor that cause heating of the susceptor as a result of one or both of resistive losses (Joule heating) and hysteresis losses (if the susceptor is magnetic). The heat generated within the susceptor is transferred to the aerosol generating substrate by conduction.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0010] A heated aerosol-generating article designed to be used in combination with an electrically operated aerosol-generating device is typically inserted into a cavity of the aerosol-generating device to be heated. As a result, the aerosol-generating material within the aerosol-generating substrate of the aerosol-generating article may become detached. Heating of the aerosol-generating substrate during use of the aerosol-generating article may cause drying of the aerosol-generating material within the aerosol-generating substrate. This may cause the aerosol-generating material to become more prone to detachment. During use of the aerosol-generating article, the aerosol-generating material detached from the aerosol-generating substrate may become detached from the aerosol-generating article. As a result, the amount and position of the aerosol-generating material within the aerosol-generating substrate may change during use of the aerosol-generating article. This may adversely affect the quality and consistency of the aerosol delivered to the user. During use of the aerosol-generating article, the aerosol-generating material detached from the aerosol-generating substrate may fall into the cavity of the aerosol-generating device. The aerosol-generating material detached from the aerosol-generating substrate of the aerosol-generating article falling into the cavity of the aerosol-generating device may prevent or inhibit the optimal functioning of the aerosol-generating device.

[0011] It is desirable to provide an aerosol-generating article for use with an aerosol-generating device in which the quality and consistency of the aerosol delivered to the user is improved as compared to known heated tobacco products. It is desirable to provide an aerosol-generating article for use in an aerosol-generating device that enables the aerosol-generating device to function optimally.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0013] The present disclosure relates to an aerosol-generating article comprising an aerosol-generating substrate. The aerosol-generating article may comprise an upstream element located upstream of the aerosol-generating substrate. The upstream element may comprise a tubular portion. The tubular portion may define an inner region of the upstream element. The upstream element may comprise a spiral sheet. The spiral sheet may define a plurality of channels extending in the longitudinal direction within the inner region. The spiral sheet may have a basis weight of about 100 grams per square meter or less.

[0014] According to a first aspect of the present invention, there is provided an aerosol-generating article comprising an aerosol-generating substrate and an upstream element located upstream of the aerosol-generating substrate, the upstream element comprising a tubular portion defining an inner region of the upstream element and a spiral sheet defining a plurality of channels extending in the longitudinal direction within the inner region, the spiral sheet having a basis weight of about 100 grams per square meter or less.

[0015] The present disclosure also relates to an aerosol-generating system. The aerosol-generating system may comprise an aerosol-generating article as described above. The aerosol-generating system may include an aerosol-generating device. The aerosol-generating device may be configured to heat the aerosol-generating substrate of the aerosol-generating article. The aerosol-generating device may comprise a housing. The housing may define a cavity. The cavity may be configured to receive the aerosol-generating article.

[0016] According to a second aspect of the present invention, there is provided an aerosol-generating system comprising an aerosol-generating article according to the first aspect of the present invention and an aerosol-generating device configured to heat the aerosol-generating substrate of the aerosol-generating article, the aerosol-generating device comprising a housing defining a cavity configured to receive the aerosol-generating article.

[0017] As used herein in the context of the present invention, the term "aerosol-generating article" is used to describe an article comprising an aerosol-generating substrate that generates an inhalable aerosol when heated and delivers it to a user.

[0018] As used herein in connection with the present invention, the term "aerosol generating substrate" is used to describe a substrate that includes an aerosol generating material having the ability to release a volatile compound that can generate an aerosol upon heating.

[0019] As used herein in connection with the present invention, the term "aerosol" is used to describe a dispersion of solid particles, or droplets, or a combination of solid particles and droplets in a gas. The aerosol can be visible or invisible. The aerosol may include not only vapors of substances that are normally liquid or solid at room temperature, but also solid particles or liquid droplets, or a combination of solid particles and liquid droplets.

[0020] As used herein in connection with the present invention, the term "aerosol generating device" is used to describe a device that interacts with an aerosol generating substrate of an aerosol generating article to generate an aerosol.

[0021] An aerosol generating article according to the present invention has a proximal end through which an aerosol exits the aerosol generating article for delivery to a user during use. The proximal end of the aerosol generating article may also be referred to as the downstream end or the mouth side end of the aerosol generating article. During use, the user directly or indirectly inhales the proximal end of the aerosol generating article to inhale the aerosol generated by the aerosol generating article.

[0022] An aerosol generating article according to the present invention has a distal end. The distal end is opposite to the proximal end. The distal end of the aerosol generating article may also be referred to as the upstream end of the aerosol generating article.

[0023] The components of an aerosol generating article according to the present invention can 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.

[0024] As used herein in the context of the present invention, the term "longitudinal direction" is used to denote the direction between the upstream end and the downstream end of the aerosol-generating article. During use, air is drawn longitudinally through the aerosol-generating article.

[0025] As used herein in the context of the present invention, the term "length" is used to describe the maximum dimension in the longitudinal direction of the aerosol-generating article or a component of the aerosol-generating article.

[0026] As used herein in the context of the present invention, the term "transverse direction" is used to describe a direction that is perpendicular to the longitudinal direction. Unless otherwise specified, the "cross-section" of an aerosol-generating article or a component of the aerosol-generating article refers to a cross-section in the transverse direction.

[0027] As used herein in the context of the present invention, the term "width" indicates the maximum dimension in the transverse direction of the aerosol-generating article or a component of the aerosol-generating article. When the aerosol-generating article has a substantially circular cross-section, the width of the aerosol-generating article corresponds to the diameter of the aerosol-generating article. When a component of the aerosol-generating article has a substantially circular cross-section, the width of the component of the aerosol-generating article corresponds to the diameter of the component of the aerosol-generating article.

[0028] As used herein in reference to the present invention, the term "tubular portion" is used to describe a generally cylindrical portion having a tubular space along its longitudinal axis. The tubular portion may have a cross-section that is substantially circular, substantially oval, or substantially elliptical. The inner region of the upstream element corresponds to the tubular space of the tubular portion. The tubular space may have a cross-section that is substantially circular, substantially oval, or substantially elliptical.

[0029] As used herein in the context of the present invention, the term "sheet" is used to describe a thin, plate-like element having a width and length that are significantly greater than its thickness.

[0030] As used herein with reference to the present invention, the term "spiraled sheet" is used to describe a sheet that includes a plurality of turns.

[0031] Unless otherwise stated, references to the properties of the spiraled sheet refer to the properties of the sheet in its spiraled form in the upstream element of the aerosol-generating article.

[0032] Unless otherwise stated, references to the properties of the sheet refer to the properties of the sheet in its non-spiraled form.

[0033] Of course, some properties of the sheet may be the same in both its spiraled and non-spiraled forms. For example, the basis weight, weight, cross-sectional area, surface area, and length of a spiraled sheet are the same as the basis weight, weight, cross-sectional area, surface area, and length of the sheet in its non-spiraled form.

[0034] As used herein with reference to the present invention, the basis weight of a spiraled sheet is the total weight of the spiraled sheet divided by the surface area of the spiraled sheet. When the spiraled sheet is formed from a rectangular sheet, the surface area of the spiraled sheet is the same as the width of the rectangular sheet multiplied by the length of the rectangular sheet. For example, when the spiraled sheet is formed from a rectangular sheet having a width of about 170 millimeters and a length of about 5 millimeters, the surface area of the spiraled sheet is about 850 square millimeters.

[0035] The aerosol generating article according to the first aspect of the present invention comprises an upstream element comprising a tubular portion defining an inner region of the upstream element and a spiral sheet defining a plurality of longitudinally extending channels within the inner region, the spiral sheet having a basis weight of about 100 grams per square meter or less. Incorporating such an upstream element advantageously provides an acceptable draw resistance (RTD) while reducing or preventing the aerosol generating material from detaching from the aerosol generating substrate during storage, transportation, and use of the aerosol generating article. Incorporating such an upstream element advantageously reduces or prevents any aerosol generating material detached from the aerosol generating substrate during use of the aerosol generating article from falling into the cavity of the aerosol generating device. Incorporating such an upstream element advantageously restricts or prevents longitudinal movement of the aerosol generating substrate during storage, transportation, and use of the aerosol generating article.

[0036] The spiral sheet divides the inner region of the upstream element into a plurality of longitudinally extending channels along which air can be drawn through the upstream element. Thereby, the spiral sheet can provide an acceptable draw resistance (RTD) while reducing the cross-sectional area of the empty space within the upstream element into which the aerosol generating material within the aerosol generating substrate can escape. This can be particularly advantageous when the aerosol generating substrate contains a plurality of fragments, pellets, or granules of the aerosol generating material.

[0037] Any aerosol generating material detached from the aerosol generating substrate must move upstream through a plurality of longitudinally extending channels defined by the spiral sheet in order to exit the upstream element and the aerosol generating article. Thereby, the spiral sheet can prevent or limit the aerosol generating material detached from the aerosol generating substrate from falling into the cavity of the aerosol generating device during use of the aerosol generating article.

[0038] By including a spiral sheet having a basis weight of 100 grams per square meter or less, the spiral sheet can have a larger cross-sectional area while retaining an appropriate total weight of the upstream element. Thereby, the spiral sheet can divide the inner region of the upstream element into more channels extending in the longitudinal direction while retaining an appropriate total weight of the upstream element.

[0039] Advantageously, the spiral sheet can act as a barrier to prevent or limit the longitudinal movement of the aerosol-generating substrate during storage, transportation, and use of the aerosol-generating article.

[0040] Accordingly, there is provided an aerosol-generating article comprising an upstream element having a tubular portion defining an inner region of the upstream element, and a spiral sheet defining a plurality of channels extending in the longitudinal direction within the inner region, wherein the spiral sheet having a basis weight of 100 grams per square meter or less according to a first aspect of the present invention may improve the quality and consistency of the aerosol delivered to the user as compared to known heated tobacco products, and may enable optimal functioning of an aerosol-generating device of an aerosol-generating system according to a second aspect of the present invention.

[0041] The spiral sheet comprises a plurality of turns. Preferably, the spiral sheet includes a plurality of non-concentric turns.

[0042] The spiral sheet defines a plurality of channels extending in the longitudinal direction within the inner region of the upstream element. The spiral sheet may be subjected to one or more crimping, folding, gathering, and pleating operations to define a plurality of channels extending in the longitudinal direction.

[0043] As used herein with respect to the present invention, the term "crimped" means a spiral sheet having a plurality of substantially parallel ridges or corrugations. Preferably, when the spiral sheet is crimped, the substantially parallel ridges or corrugations of the spiral sheet extend in the longitudinal direction of the aerosol-generating article.

[0044] As used herein with respect to the present invention, the term "assembled" means that the sheet is compressed or shrunk substantially transversely to the longitudinal axis of the aerosol-generating article.

[0045] The spiral sheet is preferably coiled. This may advantageously reduce fluctuations in the cross-sectional area of a plurality of longitudinally extending channels defined by the spiral sheet within the inner region of the upstream element.

[0046] Including a coiled spiral sheet within the upstream element may advantageously avoid or reduce the presence of longitudinally extending channels having a very large cross-sectional area within the inner region of the upstream element. The presence of longitudinally extending channels having a very large cross-sectional area within the inner region of the upstream element can adversely affect the ability of the upstream element to prevent or limit the upstream movement of aerosol-generating material from the aerosol-generating substrate.

[0047] Including a coiled spiral sheet in the upstream element may advantageously avoid or reduce the presence of longitudinally extending channels having a very small cross-sectional area within the inner region of the upstream element. The presence of longitudinally extending channels having a very small cross-sectional area within the inner region of the upstream element can increase the RTD of the upstream element beyond an acceptable level or a desired level.

[0048] When the spiral sheet is coiled, adjacent ridges or corrugations of the spiral sheet may be spaced from each other by about 1.2 millimeters or less, about 1 millimeter or less, or about 0.8 millimeters or less. For example, adjacent ridges or corrugations may be spaced from each other by a gap of about 0.5 millimeters or less. The spacing between adjacent ridges or corrugations may be selected based on the desired size of the plurality of longitudinally extending channels.

[0049] The spiral sheet may be assembled after being coiled. That is, the spiral sheet may be an assembly of coiled sheets.

[0050] At least a portion of the plurality of channels extending in the major axis direction may be defined only by the spiral sheet.

[0051] At least a portion of the plurality of channels extending in the major axis direction may be defined by the spiral sheet and the tubular portion. For example, one or more channels extending in the major axis direction adjacent to the tubular portion of the upstream element may be defined by the spiral sheet and the tubular portion. The spiral sheet may contact the tubular portion along the major axis direction to define a channel extending in the major axis direction.

[0052] The spiral sheet is located in the inner region of the upstream element.

[0053] The spiral sheet may extend partway along the length of the upstream element.

[0054] The spiral sheet may extend from the downstream end of the upstream element to the upstream end of the upstream element. This can advantageously help prevent or limit the upstream movement of the aerosol generating material from the aerosol generating substrate.

[0055] The spiral sheet may extend from the downstream end of the upstream element to the upstream end of the upstream element. This can advantageously help prevent the aerosol generating material detached from the aerosol generating substrate from falling from the upstream end of the aerosol generating article.

[0056] Preferably, the spiral sheet extends from the upstream end of the upstream element to the downstream end of the upstream element. That is, preferably, the spiral sheet extends along the entire length of the upstream element.

[0057] The length of the spiral sheet may be substantially the same as the length of the upstream element. This can advantageously simplify the manufacture of the upstream element. For example, this can advantageously enable a plurality of upstream elements to be manufactured from a single continuous rod.

[0058] The plurality of channels extending in the major axis direction may extend from the downstream end of the upstream element toward the upstream end of the upstream element.

[0059] The plurality of channels extending in the major axis direction may extend from the upstream end of the upstream element toward the downstream end of the upstream element.

[0060] The plurality of channels extending in the major axis direction preferably extend from the upstream end of the upstream element to the downstream end of the upstream element. That is, the plurality of channels extending in the major axis direction preferably extend along the entire length of the upstream element.

[0061] The spiral sheet has a basis weight of about 100 g / m² or less. The spiral sheet may have a basis weight of about 80 g / m² or less, about 70 g / m² or less, or about 50 g / m² or less.

[0062] The spiral sheet may have a basis weight of at least about 10 g / m², at least about 15 g / m², or at least about 20 g / m².

[0063] The spiral sheet may have a basis weight of about 10 g / m² to about 100 g / m², about 10 g / m² to about 80 g / m², about 10 g / m² to about 70 g / m², or about 10 g / m² to about 50 g / m².

[0064] The spiral sheet may have a basis weight of about 15 g / m² to about 100 g / m², about 15 g / m² to about 80 g / m², about 15 g / m² to about 70 g / m², or about 15 g / m² to about 50 g / m².

[0065] The spiral sheet may have a basis weight of about 20 grams per square meter to about 100 grams per square meter, about 20 grams per square meter to about 80 grams per square meter, about 20 grams per square meter to about 70 grams per square meter, or about 20 grams per square meter to about 50 grams per square meter.

[0066] The basis weight of the spiral sheet can be selected based on the balance between the ability of the upstream element to reduce or prevent the aerosol generating material from detaching from the aerosol generating substrate during storage, transportation, and use of the aerosol generating article, and the total weight of the upstream element.

[0067] The basis weight of the spiral sheet can be selected such that the spiral sheet can withstand deformation during storage, transportation, and use of the aerosol generating article.

[0068] The spiral sheet may have a weight of about 100 milligrams or less, about 75 milligrams or less, or about 50 milligrams or less.

[0069] The spiral sheet may have a weight of at least about 10 milligrams, at least about 15 milligrams, or at least about 20 milligrams.

[0070] The spiral sheet may have a weight of about 10 milligrams to about 100 milligrams, about 10 milligrams to about 75 milligrams, or about 10 milligrams to about 50 milligrams.

[0071] The spiral sheet may have a weight of about 15 milligrams to about 100 milligrams, about 15 milligrams to about 75 milligrams, or about 15 milligrams to about 50 milligrams.

[0072] The spiral sheet may have a weight of about 20 milligrams to about 100 milligrams, about 20 milligrams to about 75 milligrams, or about 20 milligrams to about 50 milligrams.

[0073] The weight of the spiral sheet can be selected based on the desired cross-sectional area of the spiral sheet and the desired total weight of the upstream element.

[0074] The spiral sheet may have an average weight per unit length of about 20 milligrams or less per millimeter, about 15 milligrams or less per millimeter, or about 10 milligrams or less per millimeter.

[0075] As used herein with reference to the present invention, the average weight per unit length of the spiral sheet is equal to the weight of the spiral sheet divided by the length of the spiral sheet. For example, if the spiral sheet has a weight of 25 milligrams and a length of 5 millimeters, the average weight per unit length of the spiral sheet is 5 milligrams / mm.

[0076] The spiral sheet may have an average weight per unit length of at least about 2 milligrams / mm, at least about 3 milligrams / mm, or at least about 4 milligrams / mm.

[0077] The spiral sheet may have an average weight per unit length of from about 2 milligrams / mm to about 20 milligrams / mm, from about 2 milligrams / mm to about 15 milligrams / mm, or from about 2 milligrams / mm to about 10 milligrams / mm.

[0078] The spiral sheet may have an average weight per unit length of from about 3 milligrams / mm to about 20 milligrams / mm, from about 3 milligrams / mm to about 15 milligrams / mm, or from about 3 milligrams / mm to about 10 milligrams / mm.

[0079] The spiral sheet may have an average weight per unit length of from about 4 milligrams / mm to about 20 milligrams / mm, from about 4 milligrams / mm to about 15 milligrams / mm, or from about 4 milligrams / mm to about 10 milligrams / mm.

[0080] The spiral sheet may have an average weight per unit volume of the inner region of about 500 micrograms or less per cubic millimeter, about 400 micrograms or less per cubic millimeter, or about 250 micrograms or less per cubic millimeter.

[0081] As used herein with reference to the present invention, the average weight of the spiral sheet per unit volume of the inner region is the weight of the spiral sheet divided by the volume of the inner region. For example, when the spiral sheet has a weight of 25 milligrams and the inner region has a volume of 200 cubic millimeters, the average weight of the spiral sheet per unit volume of the inner region is about 125 micrograms per cubic millimeter.

[0082] The spiral sheet may have an average weight per unit volume of the inner region of at least about 50 micrograms per cubic millimeter, at least about 75 micrograms per cubic millimeter, or at least about 100 micrograms per cubic millimeter.

[0083] The spiral sheet may have an average weight per unit volume of the inner region of about 50 micrograms / cubic millimeter to about 500 micrograms / cubic millimeter, about 50 micrograms / cubic millimeter to about 400 micrograms / cubic millimeter, or about 50 micrograms / cubic millimeter to about 250 micrograms / cubic millimeter.

[0084] The spiral sheet may have an average weight per unit volume of the inner region of about 75 micrograms / cubic millimeter to about 500 micrograms / cubic millimeter, about 75 micrograms / cubic millimeter to about 400 micrograms / cubic millimeter, or about 75 micrograms / cubic millimeter to about 250 micrograms / cubic millimeter.

[0085] The spiral sheet may have an average weight per unit volume of the inner region of about 100 micrograms per cubic millimeter to about 500 micrograms per cubic millimeter, about 100 micrograms per cubic millimeter to about 400 micrograms per cubic millimeter, or about 100 micrograms per cubic millimeter to about 250 micrograms per cubic millimeter.

[0086] The spiral sheet may have an average weight per unit volume of the inner region that is less than the density of the aerosol generation substrate.

[0087] The sheet may have a thickness of about 300 micrometers or less, about 200 micrometers or less, or about 150 micrometers or less. The sheet may have a thickness of at least about 30 micrometers, at least about 45 micrometers, or at least about 60 micrometers.

[0088] The sheet may have a thickness of about 30 micrometers to about 300 micrometers, about 30 micrometers to about 200 micrometers, or about 30 micrometers to about 150 micrometers.

[0089] The sheet may have a thickness of about 45 micrometers to about 300 micrometers, about 45 micrometers to about 200 micrometers, or about 45 micrometers to about 150 micrometers.

[0090] The sheet may have a thickness of about 60 micrometers to about 300 micrometers, about 60 micrometers to about 200 micrometers, or about 60 micrometers to about 150 micrometers.

[0091] The thickness of the sheet may be selected to enable one or more of curling, gathering, pleating, and folding of the sheet. The thickness of the sheet may be selected based on the desired cross-sectional area of the spiral sheet.

[0092] The spiral sheet may have a cross-sectional area of at least about 5 square millimeters, at least about 8 square millimeters, or at least about 10 square millimeters.

[0093] The cross-sectional area of the spiral sheet is the same as the cross-sectional area of the sheet in its non-spiral form. The cross-sectional area of the spiral sheet is the product of the thickness of the sheet and the width of the sheet in that cross-section.

[0094] The spiral sheet may have a cross-sectional area of about 30 square millimeters or less, about 25 square millimeters or less, or about 20 square millimeters or less.

[0095] The spiral sheet may have a cross-sectional area of from about 5 square millimeters to about 30 square millimeters, from about 5 square millimeters to about 25 square millimeters, and from about 5 square millimeters to about 20 square millimeters.

[0096] The spiral sheet may have a cross-sectional area of from about 8 square millimeters to about 30 square millimeters, from about 8 square millimeters to about 25 square millimeters, or from about 8 square millimeters to about 20 square millimeters.

[0097] The spiral sheet may have a cross-sectional area in the major axis direction of from about 10 square millimeters to about 30 square millimeters, from about 10 square millimeters to about 25 square millimeters, and from about 10 square millimeters to about 20 square millimeters.

[0098] Preferably, the cross-sectional area of the spiral sheet is substantially constant along the length of the spiral sheet.

[0099] The spiral sheet may have a surface area of at least about 250 square millimeters, at least about 400 square millimeters, or at least about 600 square millimeters.

[0100] The spiral sheet may have a surface area of about 1500 square millimeters or less, about 1350 square millimeters or less, or about 1250 square millimeters or less.

[0101] The spiral sheet may have a surface area of about 250 square millimeters to about 1500 square millimeters, about 250 square millimeters to about 1350 square millimeters, or about 250 square millimeters to about 1250 square millimeters.

[0102] The spiral sheet may have a surface area of about 400 square millimeters to about 1500 square millimeters, about 400 square millimeters to about 1350 square millimeters, or about 400 square millimeters to about 1250 square millimeters.

[0103] The spiral sheet may have a surface area of about 600 square millimeters to about 1500 square millimeters, about 600 square millimeters to about 1350 square millimeters, or about 600 square millimeters to about 1250 square millimeters.

[0104] The surface area of the spiral sheet can be selected based on the desired cross-sectional area of the spiral sheet. The surface area of the spiral sheet can be selected based on the desired RTD of the upstream element.

[0105] The spiral sheet may have an average surface area per unit length of at least about 50 square millimeters per millimeter, at least about 80 square millimeters per millimeter, or at least about 120 square millimeters per millimeter.

[0106] As used herein with reference to the present invention, the average surface area per unit length of the spiral sheet is equal to the surface area of the spiral sheet divided by the length of the spiral sheet. For example, if the spiral sheet has a surface area of 850 square millimeters and a length of 5 millimeters, the average surface area per unit length of the spiral sheet is 170 square millimeters / mm.

[0107] The spiral sheet may have an average surface area per unit length of about 300 square millimeters or less, about 270 square millimeters or less, or about 250 square millimeters or less per millimeter.

[0108] The spiral sheet may have an average surface area per unit length of about 50 square millimeters / mm to about 300 square millimeters / mm, about 50 square millimeters / mm to about 270 square millimeters / mm, or about 50 square millimeters / mm to about 250 square millimeters / mm.

[0109] The spiral sheet may have an average surface area per unit length of about 80 square millimeters / mm to about 300 square millimeters / mm, about 80 square millimeters / mm to about 270 square millimeters / mm, or about 80 square millimeters / mm to about 250 square millimeters / mm.

[0110] The spiral sheet may have an average surface area per unit length of about 120 square millimeters / mm to about 300 square millimeters / mm, about 120 square millimeters / mm to about 270 square millimeters / mm, or about 120 square millimeters / mm to about 250 square millimeters / mm.

[0111] The spiral sheet may have a length of at least about 2 millimeters, at least about 3 millimeters, or at least about 4 millimeters.

[0112] The spiral sheet may have a length of about 10 millimeters or less, about 8 millimeters or less, or about 6 millimeters or less.

[0113] The spiral sheet may have a length of about 2 millimeters to about 10 millimeters, about 2 millimeters to about 8 millimeters, or about 2 millimeters to about 6 millimeters.

[0114] The spiral sheet can have a length of about 3 millimeters to about 10 millimeters, about 3 millimeters to about 8 millimeters, or about 3 millimeters to about 6 millimeters.

[0115] The spiral sheet can have a length of about 4 millimeters to about 10 millimeters, about 4 millimeters to about 8 millimeters, or about 4 millimeters to about 6 millimeters.

[0116] For example, the spiral sheet may have a length of about 5 millimeters.

[0117] The length of the spiral sheet is preferably substantially the same as the length of the upstream element.

[0118] When the aerosol generating material comes out of one of the plurality of channels extending in the longitudinal direction from the aerosol generating substrate, the aerosol generating material that has come out blocks the channel extending in the longitudinal direction, reducing or preventing further aerosol generating material from coming out into the same channel extending in the longitudinal direction. Increasing the length of the plurality of channels extending in the longitudinal direction may enhance the ability of the upstream element to reduce or prevent further aerosol generating material from coming out into the plurality of channels extending in the longitudinal direction during storage, transportation, and use of the aerosol generating article. Increasing the length of the plurality of channels extending in the longitudinal direction may also increase the likelihood that any aerosol generating material that has come out into the plurality of channels extending in the longitudinal direction is retained within the plurality of channels extending in the longitudinal direction.

[0119] Increasing the length of the plurality of channels extending in the longitudinal direction may increase the RTD of the upstream element.

[0120] The length of the sheet can be selected based on the balance between the ability of the upstream element to prevent or limit the upstream movement of the aerosol generating material within the aerosol generating substrate and the RTD of the upstream element.

[0121] The sheet may have a width of at least about 50 millimeters, at least about 80 millimeters, or at least about 120 millimeters.

[0122] The sheet may have a width of about 300 millimeters or less, about 270 millimeters or less, or about 250 millimeters or less.

[0123] The sheet can have a width of from about 50 millimeters to about 300 millimeters, from about 50 millimeters to about 270 millimeters, or from about 50 millimeters to about 250 millimeters.

[0124] The sheet can have a width of from about 80 millimeters to about 300 millimeters, from about 80 millimeters to about 270 millimeters, or from about 80 millimeters to about 250 millimeters.

[0125] The sheet can have a width of from about 120 millimeters to about 300 millimeters, from about 120 millimeters to about 270 millimeters, or from about 120 millimeters to about 250 millimeters.

[0126] The width of the sheet and the thickness of the sheet determine the cross-sectional area of the sheet and thus the cross-sectional area of the corresponding helical sheet. Increasing the width of the sheet can reduce the total cross-sectional area of the plurality of channels extending in the longitudinal direction. This may enhance the ability of the upstream element to reduce or prevent the aerosol generating material from detaching from the aerosol generating substrate during storage, transportation, and use of the aerosol generating article. This can also increase the RTD of the upstream element. The width of the sheet can be selected based on the balance between the ability of the upstream element to prevent or limit the upstream movement of the aerosol generating material and the RTD of the upstream element.

[0127] Preferably, the sheet does not substantially shrink upon exposure to heat.

[0128] The sheet may have a linear shrinkage rate of about 4 percent or less, about 3 percent or less, about 2 percent or less, about 1.5 percent or less, about 1 percent or less, about 0.75 percent or less, or about 0.5 percent or less when measured according to Test Method A described herein. The sheet may have a linear shrinkage rate of about 0 percent when measured according to Test Method A described herein.

[0129] As used herein in connection with the present invention, the term "linear shrinkage rate" is used to describe the average decrease in the length and width of the sheet after exposure to heat, and is expressed as a percentage of the original length and width of the sheet before exposure to heat.

[0130] The sheet may have an area shrinkage rate of about 8 percent or less, about 6 percent or less, about 3 percent or less, about 2 percent or less, about 1.5 percent or less, or about 1 percent or less when measured according to Test Method A described herein. The sheet may have an area shrinkage rate of about 0 percent when measured according to Test Method A described herein.

[0131] As used herein in connection with the present invention, the term "area shrinkage rate" is used to describe the average decrease in the area of the sheet after exposure to heat, and is expressed as a percentage of the original area of the sheet before exposure to heat.

[0132] Sheets that are more resistant to shrinkage under exposure to heat have a smaller linear shrinkage rate and a smaller area shrinkage rate.

[0133] Test method A Five square samples of the sheet, each having a side length of 10 millimeters, are conditioned in air at 23°C ± 2°C and 50% ± 5% relative humidity for at least 40 hours.

[0134] The samples are then heated in an oven at 120°C ± 2°C for 5 minutes.

[0135] Next, remove the sample from the oven and cool it to 23°C + / - 2°C.

[0136] Next, the side lengths of each of the five samples are measured. From the measurements, the average side length and the average area are determined. The average side length is determined by dividing the sum of the measured side lengths of each of the five samples, in millimeters, by 20. The area of each of the five samples is calculated by multiplying the measured side lengths of two adjacent sides of each of the five samples. The average area is determined by dividing the sum of the calculated areas of each of the five samples, in square millimeters, by 5.

[0137] The linear shrinkage rate of the sheet is given by:

[0138] [Equation 1] JPEG2025521904000002.jpg18157

[0139] The area shrinkage rate of the sheet is given by:

[0140] [Equation 2] JPEG2025521904000003.jpg18108

[0141] The spiral sheet is preferably formed from a heat-resistant material. For example, the spiral sheet can be formed from a material that withstands a temperature of up to 350 degrees Celsius. This can advantageously help to ensure that the upstream elements are not adversely affected by the heating of the aerosol-generating substrate during use of the aerosol-generating article. For example, forming the spiral sheet from a heat-resistant material can advantageously help to ensure that the spiral sheet and the upstream elements do not deform significantly during use of the aerosol-generating article. Thereby, advantageously, the RTD of the upstream elements can be kept substantially constant throughout the use of the aerosol-generating article.

[0142] Forming a sheet wound from a heat-resistant material can advantageously reduce the risk that the spiral sheet will come off the upstream element or the aerosol-generating article during storage, transportation, and use of the aerosol-generating article.

[0143] Since the change in the dimensions of the upstream element after use of the aerosol-generating article is minimal or non-existent, when removing the used aerosol-generating article from the cavity of the aerosol-generating device, the upstream element can act as a cleaning tool for cleaning the cavity of the aerosol-generating device.

[0144] The spiral sheet can be formed from any suitable material. Suitable materials include, but are not limited to, paper-based materials such as paper and cardboard, and polylactic acid (PLA).

[0145] The spiral sheet is preferably formed from a biodegradable material.

[0146] The spiral sheet is preferably formed from a paper-based material. That is, the spiral sheet is preferably a spiral sheet of a paper-based material.

[0147] More preferably, the spiral sheet is formed from paper. That is, the spiral sheet is more preferably a spiral paper sheet. The paper sheet may suitably be heat-resistant. The paper sheet may not substantially shrink upon exposure to heat.

[0148] An upstream element including a spiral paper sheet can exhibit better heat resistance than, for example, a plug of cellulose acetate.

[0149] The spiral sheet may include a flame-retardant coating. The flame-retardant coating can prevent one or both of wrinkling and carbonization of the spiral sheet during use of the aerosol-generating article.

[0150] The flame-retardant coating may include a flame-retardant composition containing one or more flame-retardant compounds.

[0151] Suitable flame retardant compounds are known in the art.

[0152] The flame retardant composition may include a polymer, at least one mono-, di-, and / or tricarboxylic acid, at least one polyphosphoric acid, pyrophosphoric acid, and / or phosphoric acid, and a mixed salt based on a hydroxide or a salt of an alkali or alkaline earth metal, wherein at least one mono-, di-, and / or tricarboxylic acid and the hydroxide or salt form a carboxylate and at least one polyphosphoric acid to form pyrophosphoric acid and / or phosphoric acid, and the hydroxide or salt forms a phosphate. The flame retardant composition further includes a carbonate of an alkali or alkaline earth metal.

[0153] The flame retardant composition may include at least one C 10 or higher fatty acid, tall oil fatty acid (TOFA), phosphorylated linseed oil, cellulose modified with phosphorylated downstream corn oil. At least one C 10 or higher fatty acid may be selected from the group consisting of capric acid, myristic acid, palmitic acid, and combinations thereof.

[0154] A plurality of channels extending in the major axis direction provide an air flow path through the upstream element.

[0155] As used herein in connection with the present invention, the term "air flow path" is used to describe a path through which air can be drawn through an aerosol-generating article or a component thereof.

[0156] Preferably, the plurality of channels extending in the major axis direction are empty.

[0157] The plurality of channels extending in the major axis direction may include at least 5 channels extending in the major axis direction, at least 10 channels extending in the major axis direction, at least 20 channels extending in the major axis direction, or at least 30 channels extending in the major axis direction. That is, the spiral sheet may define at least 5 channels extending in the major axis direction within the inner region, at least 10 channels extending in the major axis direction within the inner region, at least 20 channels extending in the major axis direction within the inner region, or at least 30 channels extending in the major axis direction within the inner region.

[0158] The plurality of channels extending in the major axis direction may have a maximum width of about 5 millimeters or less. That is, any one of the plurality of channels extending in the major axis direction may not have a width exceeding about 5 millimeters.

[0159] The plurality of channels extending in the major axis direction may have a maximum width of about 4 millimeters or less, or about 3 millimeters or less.

[0160] The plurality of channels extending in the major axis direction may have a maximum cross-sectional area of about 4 square millimeters or less. That is, any one of the plurality of channels extending in the major axis direction may not have a cross-sectional area exceeding 4 square millimeters.

[0161] The plurality of channels extending in the major axis direction may have a maximum cross-sectional area of about 3 square millimeters or less, or about 2 square millimeters or less.

[0162] The plurality of channels extending in the major axis direction may have an average width of about 4 millimeters or less, about 3 millimeters or less, or about 2 millimeters or less.

[0163] As used herein with respect to the present invention, the average width of the plurality of channels extending in the major axis direction is the average of the widths of each of the channels extending in the major axis direction.

[0164] The plurality of channels extending in the major axis direction may have an average cross-sectional area of about 3 square millimeters or less, about 2 square millimeters or less, or about 1 square millimeter or less.

[0165] As used herein with respect to the present invention, the average cross-sectional area of the plurality of channels extending in the major axis direction is the average of the cross-sectional areas of each of the channels extending in the major axis direction.

[0166] The ratio of the maximum width of the plurality of channels extending in the major axis direction to the length of the spiral sheet may be about 1 or less, about 0.8 or less, or about 0.6 or less.

[0167] The ratio of the maximum cross-sectional area of the plurality of channels extending in the major axis direction to the length of the spiral sheet may be about 0.8 or less, about 0.6 or less, or about 0.4 or less.

[0168] The ratio of the average width of the plurality of channels extending in the major axis direction to the length of the spiral sheet may be about 0.8 or less, about 0.6 or less, or about 0.4 or less.

[0169] The ratio of the average cross-sectional area of the plurality of channels extending in the major axis direction to the length of the spiral sheet may be about 0.6 or less, about 0.4 or less, or about 0.2 or less.

[0170] It is preferable that the total cross-sectional area of the plurality of channels is substantially constant along the entire length of the spiral sheet. For example, the cross-sectional area of each of the plurality of channels extending in the major axis direction may be substantially constant along the entire length of the spiral sheet.

[0171] The tubular portion defines an inner region of the upstream element. The spiral sheet is located within the inner region. The spiral sheet defines a plurality of channels extending in the major axis direction within the inner region.

[0172] The total weight of the upstream element may be substantially the same as the combined weight of the tubular portion and the spiral sheet.

[0173] The upstream element may consist of a tubular portion and a spiral sheet.

[0174] The tubular portion preferably has sufficient rigidity so that the tubular portion does not collapse during storage, transportation, and use of the aerosol-generating article. The folding of the tubular portion can result in a change in one or both of the shape and size of one or more of the channels extending in the long axis direction. For example, the collapse of the tubular portion can result in a change in one or both of the shape and size of one or more of the channels extending in the long axis direction that are adjacent to the tubular portion and defined by the spiral sheet and the tubular portion. Thereby, the drawing resistance of the upstream element can increase. This can also adversely affect the ability of the upstream element to prevent or limit the upstream movement of the aerosol-generating material from the aerosol-generating substrate.

[0175] The tubular portion may have a thickness of at least about 20 micrometers, at least about 40 micrometers, or at least about 60 micrometers.

[0176] The tubular portion may have a thickness of about 140 micrometers or less, about 120 micrometers or less, or about 100 micrometers or less.

[0177] The tubular portion may have a thickness of about 20 micrometers to about 140 micrometers, about 20 micrometers to about 120 micrometers, or about 20 micrometers to about 100 micrometers.

[0178] The tubular portion may have a thickness of about 40 micrometers to about 140 micrometers, about 40 micrometers to about 120 micrometers, or about 40 micrometers to about 100 micrometers.

[0179] The tubular portion may have a thickness of about 60 micrometers to about 140 micrometers, about 60 micrometers to about 120 micrometers, or about 60 micrometers to about 100 micrometers.

[0180] The thickness of the tubular portion may be selected based on the desired rigidity of the tubular portion.

[0181] The tubular portion may be formed by a wrapper surrounding the spiral sheet.

[0182] When the tubular portion is formed by a wrapper, the thickness of the tubular portion may be the same as the thickness of the wrapper.

[0183] The wrapper may have a basis weight of about 10 grams per square meter, at least about 15 grams per square meter, or at least about 20 grams per square meter.

[0184] The wrapper may have a basis weight of about 100 grams per square meter or less, about 80 grams per square meter or less, or about 60 grams per square meter or less.

[0185] The wrapper may have a basis weight of about 10 grams per square meter to about 100 grams per square meter, about 10 grams per square meter to about 80 grams per square meter, or about 10 grams per square meter to about 60 grams per square meter.

[0186] The wrapper may have a basis weight of about 15 grams per square meter to about 100 grams per square meter, about 15 grams per square meter to about 80 grams per square meter, or about 15 grams per square meter to about 60 grams per square meter.

[0187] The wrapper may have a basis weight of about 20 grams per square meter to about 100 grams per square meter, about 20 grams per square meter to about 80 grams per square meter, or about 20 grams per square meter to about 60 grams per square meter.

[0188] The basis weight of the wrapper may be selected based on the desired rigidity of the upstream element.

[0189] The wrapper may be a paper wrapper.

[0190] The length of the tubular portion may be substantially the same as the length of the upstream element.

[0191] The width of the tubular portion may be the same as the width of the upstream element.

[0192] Unless otherwise stated, the draw resistance (RTD) of an aerosol-generating article or a component of an aerosol-generating article is measured in accordance with ISO 6565-2015 at the proximal or downstream end of the aerosol-generating article or its component at a volume flow rate of about 17.5 milliliters per second, a temperature of about 22 °C, a pressure of about 101 kPa (about 760 Torr), and a relative humidity of about 60%.

[0193] The RTD of the upstream element per unit length may be at least 0.2 millimeter H2O per millimeter, or at least about 0.5 millimeter H2O per millimeter, or at least about 1 millimeter H2O per millimeter.

[0194] The RTD of the upstream element per unit length may be about 3 millimeters H2O or less per millimeter, about 2.5 millimeters H2O or less per millimeter, or about 2 millimeters H2O or less per millimeter.

[0195] The RTD of the upstream element may be from about 0.2 millimeter H2O per millimeter to about 3 millimeters H2O per millimeter, from about 0.2 millimeter H2O per millimeter to about 2.5 millimeters H2O per millimeter, or from about 0.2 millimeter H2O per millimeter to about 2 millimeters H2O per millimeter.

[0196] The RTD of the upstream element may be about 0.5 millimeter H2O per millimeter to about 3 millimeters H2O per millimeter, about 0.5 millimeter H2O per millimeter to about 2.5 millimeters H2O per millimeter, or about 0.5 millimeter H2O per millimeter to about 2 millimeters H2O per millimeter.

[0197] The RTD of the upstream element may be about 1 millimeter H2O per millimeter to about 3 millimeters H2O per millimeter, about 1 millimeter H2O per millimeter to about 2.5 millimeters H2O per millimeter, or about 1 millimeter H2O per millimeter to about 2 millimeters H2O per millimeter.

[0198] For example, the RTD of the upstream element may be about 1.5 millimeters H2O per millimeter of the length of the upstream element.

[0199] The RTD of the upstream element may be at least about 1 millimeter H2O, or at least 2.5 millimeters H2O, or at least 5 millimeters H2O.

[0200] The RTD of the upstream element may be about 15 millimeters H2O or less, about 12.5 millimeters H2O or less, or about 10 millimeters H2O or less.

[0201] The RTD of the upstream element may be about 1 millimeter H2O to about 15 millimeters H2O, about 1 millimeter H2O to about 12.5 millimeters H2O, or about 1 millimeter H2O to about 10 millimeters H2O.

[0202] The RTD of the upstream element may be about 2.5 millimeters H2O to about 15 millimeters H2O, about 2.5 millimeters H2O to about 12.5 millimeters H2O, or about 2.5 millimeters H2O to about 10 millimeters H2O.

[0203] The RTD of the upstream element may be from about 5 millimeters H2O to about 15 millimeters H2O, from about 5 millimeters H2O to about 12.5 millimeters H2O, or from about 5 millimeters H2O to about 10 millimeters H2O.

[0204] For example, the RTD of the upstream element may be about 7.5 millimeters H2O.

[0205] The RTD of the upstream element may be smaller than the RTD of the aerosol generation substrate.

[0206] The upstream element may provide less than 50 percent of the overall RTD of the aerosol generation article. That is, the ratio of the RTD of the upstream element to the overall RTD of the aerosol generation article may be less than 0.5.

[0207] The ratio of the RTD of the upstream element to the overall RTD of the aerosol generation article may be about 0.4 or less, about 0.3 or less, or about 0.25 or less.

[0208] The ratio of the RTD of the upstream element to the overall RTD of the aerosol generation article may be at least about 0.01, at least about 0.03, or at least about 0.05.

[0209] The upstream element may have a porosity of at least about 40 percent, at least about 45 percent, or at least about 50 percent.

[0210] The upstream element may have a porosity of about 85 percent or less, about 80 percent or less, or about 75 percent or less.

[0211] As used herein in connection with the present invention, the porosity of an upstream element is defined by the ratio of the sum of the cross-sectional areas of the components within the inner region of the upstream element to the cross-sectional area of the inner region. For an upstream element having a higher porosity, a smaller proportion of the cross-sectional area of the inner region is occupied by the components of the inner region and a larger proportion of the cross-sectional area of the inner region is empty space. As an upstream element having a lower porosity, a larger proportion of the cross-sectional area of the inner region is occupied by the components of the inner region and a smaller proportion of the cross-sectional area of the inner region is empty space.

[0212] When the upstream element consists of a tubular portion and a spiral sheet, the porosity of the upstream element is defined by the ratio of the cross-sectional area of the spiral sheet to the cross-sectional area of the inner region expressed as a percentage.

[0213] When the tubular portion defines an inner region with a substantially circular cross-section, the cross-sectional area of the inner region is defined by the inner diameter of the tubular portion. For example, if the spiral sheet has a cross-sectional area of 15 square millimeters and the inner diameter of the tubular portion is 7 millimeters, the porosity of the upstream element is approximately 61%.

[0214] The upstream element may have a density lower than the density of the aerosol generating substrate.

[0215] As used herein in connection with the present invention, the density of the upstream element refers to the bulk density of the upstream element. The bulk density of the upstream element is the total weight of the upstream element divided by the volume of the upstream element. For example, if the upstream element is substantially cylindrical and has a total weight of about 30 milligrams, a length of about 5 millimeters, and an outer diameter of about 7.1 millimeters, the upstream element has a bulk density of about 150 milligrams per cubic centimeter.

[0216] The aerosol generating article may have a hardness of at least about 80 percent, at least about 85 percent, or at least about 90 percent in the upstream element. This may advantageously reduce or avoid deformation of the upstream element during storage, transportation, and use of the aerosol generating article.

[0217] As used herein with respect to the present invention, the term "hardness" is used to represent the resistance to lateral deformation of an aerosol-generating article. Hardness is generally expressed as a percentage. The hardness of an aerosol-generating article is determined by measuring the width of the aerosol-generating article before applying a set load transversely to the aerosol-generating article and then (while the load is still applied) measuring the compressed width of the aerosol-generating article after applying the set load over a set period. Hardness is given by the following.

[0218] [Equation 3] JPEG2025521904000004.jpg1398

[0219] In the formula, W S is the original (not depressed) width, and W d is the compressed width after applying the set load over a set period. The harder the material, the closer the hardness is to 100 percent.

[0220] To determine the hardness of a part (such as an upstream element) of an aerosol-generating article, the aerosol-generating articles are arranged parallel to each other in a plane and a set load is applied over a set period to the same part of each aerosol-generating article being tested. This test is carried out using a well-known DD60A Densimeter device (manufactured and commercially available by Heinr Borgwaldt GmbH, Germany), which is equipped with a measuring head for aerosol-generating articles and also comes with an aerosol-generating article container.

[0221] Loading is applied using two load - applying cylindrical rods that extend across the width of all aerosol - generating articles at once. By the standard test method for this device, the test should be conducted so that twenty contact points occur between the aerosol - generating article and the load - applying cylindrical rods. In some cases, the upstream element being tested may be long enough such that only ten aerosol - generating articles are required for each aerosol - generating article to form twenty contact points (since each is long enough to extend between both rods) that contact both load - applying rods. In other cases, if the upstream element is overly short to achieve this, as further discussed below, twenty aerosol - generating articles should be used to form twenty contact points, with each aerosol - generating article contacting only one of the load - applying rods.

[0222] Two additional fixed cylindrical rods are positioned under the aerosol - generating articles to support the aerosol - generating articles and counter the load applied by each of the load - applying cylindrical rods.

[0223] For such a device, in the standard operating procedure, an overall load of 2 kg is applied for 20 seconds. After 20 seconds (and with the load still applied to the aerosol - generating article), the depression in the load - applying cylindrical rod is determined and then used to calculate the hardness from the above equation. The temperature is maintained within the range of 22 degrees Celsius plus or minus 2 degrees. The above - described test is called the DD60A test. The standard method for measuring the hardness of an aerosol - generating article is before the aerosol - generating article is used. Additional information regarding the measurement of the average radial hardness can be found, for example, in U.S. Patent Application Publication No. 2016 / 0128378 A1.

[0224] For example, the upstream element may have a length of at least about 2 millimeters, at least about 3 millimeters, or at least about 4 millimeters.

[0225] The upstream element may have a length of about 10 millimeters or less, about 8 millimeters or less, or about 6 millimeters or less.

[0226] The upstream element may have a length of from about 2 millimeters to about 10 millimeters, from about 2 millimeters to about 8 millimeters, or from about 2 millimeters to about 6 millimeters.

[0227] The upstream element may have a length of from about 3 millimeters to about 10 millimeters, from about 3 millimeters to about 8 millimeters, or from about 3 millimeters to about 6 millimeters.

[0228] The upstream element may have a length of from about 4 millimeters to about 10 millimeters, from about 4 millimeters to about 8 millimeters, or from about 4 millimeters to about 6 millimeters.

[0229] For example, the upstream element may have a length of about 5 millimeters.

[0230] The length of the upstream element can be selected based on a desired balance between the ability of the upstream element to prevent or restrict upstream movement of the aerosol-generating material from the aerosol-generating substrate and the RTD of the upstream element.

[0231] The length of the upstream element may be selected based on the desired overall length of the aerosol-generating article.

[0232] The ratio of the length of the upstream element to the overall length of the aerosol-generating article may be at least about 0.03, at least about 0.05, or at least about 0.07.

[0233] The ratio of the length of the upstream element to the overall length of the aerosol-generating article may be about 0.25 or less, about 0.2 or less, or about 0.15 or less.

[0234] The upstream element preferably has a substantially circular cross-section.

[0235] The upstream element may have an outer diameter of at least about 5 millimeters, at least about 6 millimeters, or at least about 7 millimeters.

[0236] The upstream element may have an outer diameter of 12 millimeters or less, about 10 millimeters or less, or about 8 millimeters or less.

[0237] The upstream element may have an outer diameter in the range of about 5 millimeters to about 12 millimeters, about 5 millimeters to about 10 millimeters, or about 5 millimeters to about 8 millimeters.

[0238] The upstream element may have an outer diameter in the range of about 6 millimeters to about 12 millimeters, about 6 millimeters to about 10 millimeters, or about 6 millimeters to about 8 millimeters.

[0239] The upstream element may have an outer diameter in the range of about 7 millimeters to about 12 millimeters, about 7 millimeters to about 10 millimeters, or about 7 millimeters to about 8 millimeters.

[0240] For example, the upstream element may have an outer diameter of about 7.1 millimeters.

[0241] Preferably, the outer diameter of the upstream element is substantially the same as the outer diameter of the aerosol generation substrate.

[0242] Preferably, the outer diameter of the upstream element is substantially the same as the outer diameter of the aerosol generation article. The upstream element is upstream of the aerosol generation substrate.

[0243] The upstream element is preferably adjacent to the aerosol generation substrate. This can advantageously improve the ability of the upstream element to prevent or limit the upstream movement of the aerosol generation material from the aerosol generation substrate.

[0244] The upstream element may be located at the upstream end of the aerosol generation article.

[0245] The aerosol-generating article may comprise an additional element upstream of the upstream element. For example, the aerosol-generating article may include a plug of cellulose acetate tow located upstream of the upstream element. The additional element upstream of the upstream element may act as a cap or cover that helps avoid damage to the upstream element.

[0246] The upstream element may comprise up to about 1 wt% aerosol former, up to about 0.5 wt% aerosol former, or up to about 0.2 wt% aerosol former, based on the dry weight of the upstream element.

[0247] The upstream element may be substantially free of aerosol former. The upstream element may be devoid of aerosol former. That is, the upstream element may comprise about 0 wt% aerosol former, based on the dry weight of the upstream element.

[0248] As further described below, the aerosol-generating substrate preferably comprises an aerosol former. The ratio of the weight of the aerosol former in the upstream element to the weight of the aerosol former in the aerosol-generating substrate, both based on the dry weight of the upstream element, is preferably about 0.2 or less, about 0.1 or less, or about 0.05 or less.

[0249] Preferably, most of the aerosol generated by the aerosol-generating article is generated by the aerosol-generating substrate. All of the aerosol generated by the aerosol-generating article may be generated by the aerosol-generating substrate.

[0250] The aerosol-generating substrate may be in the form of a rod.

[0251] As used herein in the context of the present invention, the term "rod" is used to denote a generally cylindrical element having a substantially circular, oval or elliptical cross-section.

[0252] The aerosol generation substrate includes an aerosol generation material surrounded by a wrapper such as a plug wrap. For example, the aerosol generation substrate may comprise an aerosol generation material surrounded by a wrapper to form a rod.

[0253] The aerosol generation substrate can have a length of at least about 8 millimeters, at least about 9 millimeters, or at least about 10 millimeters.

[0254] The length of the aerosol generation substrate may be about 16 millimeters or less, about 15 millimeters or less, or about 14 millimeters or less.

[0255] The aerosol generation substrate may have a length of about 8 millimeters to about 16 millimeters, about 8 millimeters to about 15 millimeters, or about 8 millimeters to about 14 millimeters.

[0256] The aerosol generation substrate may have a length of about 9 millimeters to about 16 millimeters, about 9 millimeters to about 15 millimeters, or about 9 millimeters to about 14 millimeters.

[0257] The aerosol generation substrate may have a length of about 10 millimeters to about 16 millimeters, about 10 millimeters to about 15 millimeters, or about 10 millimeters to about 14 millimeters.

[0258] For example, the aerosol generation substrate can have a length of about 12 millimeters.

[0259] The ratio of the length of the aerosol generation substrate to the total length of the aerosol generation article may be at least about 0.10, at least about 0.15, or at least about 0.20.

[0260] The ratio of the length of the aerosol generation substrate to the total length of the aerosol generation article may be 0.40 or less, about 0.35 or less, or about 0.3 or less.

[0261] The ratio of the length of the aerosol generating substrate to the total length of the aerosol generating article may be from about 0.10 to about 0.40, from about 0.10 to about 0.35, or from about 0.10 to about 0.30.

[0262] The ratio of the length of the aerosol generating substrate to the total length of the aerosol generating article may be from about 0.15 to about 0.40, from about 0.15 to about 0.35, or from about 0.15 to about 0.30.

[0263] The ratio of the length of the aerosol generating substrate to the total length of the aerosol generating article may be from about 0.20 to about 0.40, from about 0.20 to about 0.35, or from about 0.20 to about 0.30.

[0264] The aerosol generating substrate preferably has a substantially circular cross-section.

[0265] The aerosol generating substrate may have an outer diameter of at least about 5 millimeters, at least about 6 millimeters, or at least about 7 millimeters.

[0266] The aerosol generating substrate may have an outer diameter of 12 millimeters or less, about 10 millimeters or less, or about 8 millimeters or less.

[0267] The aerosol generating substrate may have an outer diameter of from about 5 millimeters to about 12 millimeters, such as an outer diameter of from about 5 millimeters to about 10 millimeters, or an outer diameter of from about 5 millimeters to about 8 millimeters.

[0268] The aerosol generating substrate may have an outer diameter of from about 6 millimeters to about 12 millimeters, such as an outer diameter of from about 6 millimeters to about 10 millimeters, or an outer diameter of from about 6 millimeters to about 8 millimeters.

[0269] The aerosol generating substrate may have an outer diameter of from about 7 millimeters to about 12 millimeters, such as an outer diameter of from about 7 millimeters to about 10 millimeters, or an outer diameter of from about 7 millimeters to about 8 millimeters.

[0270] For example, the aerosol generating substrate may have an outer diameter of about 7.1 millimeters.

[0271] The aerosol generating substrate may have a density of at least about 150 milligrams per cubic centimeter, at least about 175 milligrams per cubic centimeter, at least about 200 milligrams per cubic centimeter, or at least or about 250 milligrams per cubic centimeter.

[0272] The aerosol generating substrate may have a density of about 500 milligrams per cubic centimeter or less, about 450 milligrams per cubic centimeter or less, about 400 milligrams per cubic centimeter or less, or about 350 milligrams per cubic centimeter or less.

[0273] The aerosol generating substrate may have a density of about 150 milligrams per cubic centimeter to about 500 milligrams per cubic centimeter, about 150 milligrams per cubic centimeter to about 450 milligrams per cubic centimeter, about 150 milligrams per cubic centimeter to about 400 milligrams per cubic centimeter, or about 150 milligrams per cubic centimeter to about 350 milligrams per cubic centimeter.

[0274] The aerosol generating substrate may have a density of about 175 milligrams per cubic centimeter to about 500 milligrams per cubic centimeter, about 175 milligrams per cubic centimeter to about 450 milligrams per cubic centimeter, about 175 milligrams per cubic centimeter to about 400 milligrams per cubic centimeter, or about 175 milligrams per cubic centimeter to about 350 milligrams per cubic centimeter.

[0275] The aerosol generation substrate may have a density of about 200 milligrams per cubic centimeter to about 500 milligrams per cubic centimeter, about 200 milligrams per cubic centimeter to about 450 milligrams per cubic centimeter, about 200 milligrams per cubic centimeter to about 400 milligrams per cubic centimeter, or about 200 milligrams per cubic centimeter to about 350 milligrams per cubic centimeter.

[0276] The aerosol generation substrate may have a density of about 250 milligrams per cubic centimeter to about 500 milligrams per cubic centimeter, about 250 milligrams per cubic centimeter to about 450 milligrams per cubic centimeter, about 250 milligrams per cubic centimeter to about 400 milligrams per cubic centimeter, or about 250 milligrams per cubic centimeter to about 350 milligrams per cubic centimeter.

[0277] For example, the density of the aerosol generation substrate is about 300 milligrams per cubic centimeter.

[0278] The RTD of the aerosol generation substrate may be at least about 4 millimeters H2O, at least 5 millimeters H2O, or at least 6 millimeters H2O.

[0279] The RTD of the aerosol generation substrate may be about 10 millimeters H2O or less, about 9 millimeters H2O or less, or about 8 millimeters H2O or less.

[0280] The RTD of the aerosol generation substrate may be about 4 millimeters H2O to about 10 millimeters H2O, about 4 millimeters H2O to about 9 millimeters H2O, or about 4 millimeters H2O to about 8 millimeters H2O.

[0281] The RTD of the aerosol generation substrate may be about 5 millimeters H2O to about 10 millimeters H2O, about 5 millimeters H2O to about 9 millimeters H2O, or about 5 millimeters H2O to about 8 millimeters H2O.

[0282] The RTD of the aerosol generating substrate may be from about 6 millimeters H2O to about 10 millimeters H2O, from about 6 millimeters H2O to about 9 millimeters H2O, or from about 6 millimeters H2O to about 8 millimeters H2O.

[0283] The aerosol generating substrate may be a solid aerosol generating substrate.

[0284] The aerosol generating substrate preferably includes an aerosol former.

[0285] 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 may be substantially resistant to thermal degradation at the temperatures normally encountered during use of the aerosol generating article. Suitable aerosol formers are, for example, polyhydric alcohols (such as triethylene glycol, 1,3 - butanediol, propylene glycol, glycerin, 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.

[0286] The aerosol former preferably includes one or more of glycerin and propylene glycol. The aerosol former may consist of glycerin, or propylene glycol, or a combination of glycerin and propylene glycol.

[0287] The aerosol generating substrate may contain at least about 5 weight percent, at least about 10 weight percent, or at least about 12 weight percent of the aerosol former, based on the dry weight of the aerosol generating substrate.

[0288] The aerosol generating substrate may have an aerosol former that is about 30 wt% or less, about 25 wt% or less, or about 20 wt% or less, based on the dry weight of the aerosol generating substrate.

[0289] The aerosol generating substrate may have an aerosol former that is from about 5 wt% to about 30 wt%, for example from about 5 wt% to about 25 wt%, or from about 5 wt% to about 20 wt%, based on the dry weight of the aerosol generating substrate.

[0290] The aerosol generating substrate may have an aerosol former that is from about 10 wt% to about 30 wt%, for example from about 10 wt% to about 25 wt%, or from about 10 wt% to about 20 wt%, based on the dry weight of the aerosol generating substrate.

[0291] The aerosol generating substrate may have an aerosol former that is from about 12 wt% to about 30 wt%, for example from about 12 wt% to about 25 wt%, or from about 12 wt% to about 20 wt%, based on the dry weight of the aerosol generating substrate.

[0292] The aerosol generating substrate may comprise shreds of a plurality of tobacco materials. The aerosol generating substrate may comprise shreds of a homogenized tobacco material.

[0293] As used herein in the context of the present invention, the term "shred" means an element having a length that is substantially greater than its width and thickness.

[0294] As used herein in the context of the present invention, the term "homogenized tobacco material" is used to describe a material formed by aggregating particulate tobacco material.

[0295] The shreds of homogenized tobacco material may be formed from a sheet of homogenized tobacco material, for example, by cutting or shredding. The shreds of homogenized tobacco material may also be formed by other methods, for example, by extrusion.

[0296] The shreds of tobacco material may have a width of at least about 0.3 millimeters, at least about 0.5 millimeters, or at least about 0.6 millimeters.

[0297] The shreds of tobacco material may have a width of about 2 millimeters or less, about 1.2 millimeters or less, or less than about 0.9 millimeters.

[0298] The shreds of tobacco material may have a width of about 0.3 millimeters to about 2 millimeters, about 0.3 millimeters to about 1.2 millimeters, or about 0.3 millimeters to about 0.9 millimeters.

[0299] The shreds of tobacco material may have a width of about 0.5 millimeters to about 2 millimeters, about 0.5 millimeters to about 1.2 millimeters, or about 0.5 millimeters to about 0.9 millimeters.

[0300] The shreds of tobacco material may have a width of about 0.6 millimeters to about 2 millimeters, about 0.6 millimeters to about 1.2 millimeters, or about 0.6 millimeters to about 0.9 millimeters.

[0301] The shreds of tobacco material may have a length of at least about 10 millimeters.

[0302] The shreds of tobacco material may have a length of about 40 millimeters or less.

[0303] The shreds of tobacco material may have a maximum length of about 10 millimeters to about 40 millimeters.

[0304] On a dry weight basis, at least about 20 weight percent of the plurality of shreds of tobacco material may extend along the entire length of the aerosol-generating substrate. On a dry weight basis, at least about 20 weight percent of the plurality of shreds of tobacco material may have a length substantially the same as the length of the aerosol-generating substrate.

[0305] On a dry weight basis, up to about 60 weight percent of the plurality of shreds of tobacco material may extend along the entire length of the aerosol-generating substrate. On a dry weight basis, up to about 60 weight percent of the plurality of shreds of tobacco material may have a length substantially the same as the length of the aerosol-generating substrate.

[0306] On a dry weight basis, from about 20 weight percent to about 60 weight percent of the plurality of shreds of tobacco material may extend along the entire length of the aerosol-generating substrate. On a dry weight basis, from about 20 weight percent to about 60 weight percent of the plurality of shreds of tobacco material may have a length substantially the same as the length of the aerosol-generating substrate.

[0307] The size of the aerosol-generating material of the aerosol-generating substrate, such as the plurality of shreds of tobacco material, can play a role in the heat distribution inside the aerosol-generating substrate. Also, the size of the aerosol-generating material can play a role in the draw resistance of the article. Further, the size of the aerosol-generating material can affect the ability of an upstream element to prevent or limit the movement of the aerosol-generating material into a channel extending in the major axis direction of the upstream element. The size of the aerosol-generating material can also affect the ability of an upstream element to prevent or limit the upstream movement of the aerosol-generating material along a channel extending in the major axis direction and out of the upstream element.

[0308] The aerosol-generating substrate may contain a plurality of pellets or granules of tobacco material. The aerosol-generating substrate may contain a plurality of homogenized pellets or granules of tobacco material.

[0309] At least about 60 weight percent of the plurality of pellets or granules may have a maximum dimension of greater than about 1 millimeter, at least about 70 weight percent of the plurality of pellets or granules may have a maximum dimension of greater than about 1 millimeter, or at least about 80 weight percent of the plurality of pellets or granules may have a maximum dimension of greater than about 1 millimeter.

[0310] When the homogenized plant material is in the form of a plurality of pellets or granules, at least about 70 weight percent of the plurality of pellets or granules may have a maximum dimension of greater than about 0.5 millimeter, at least about 80 weight percent of the plurality of pellets or granules may have a maximum dimension of greater than about 0.5 millimeter, or at least about 90 weight percent of the plurality of pellets or granules may have a maximum dimension of greater than about 0.5 millimeter.

[0311] For example, at least about 80 weight percent of the plurality of pellets or granules may have a maximum dimension of greater than about 1 millimeter, and at least about 90 weight percent of the plurality of pellets or granules may have a maximum dimension of greater than about 0.5 millimeter.

[0312] The aerosol-generating substrate can include one or more sheets of tobacco material.

[0313] The aerosol-generating substrate can include one or more sheets of homogenized tobacco material.

[0314] Each single sheet or sheet of tobacco material can individually have a thickness of at least about 100 micrometers, at least about 150 micrometers, or at least about 300 micrometers.

[0315] As used herein with respect to the present invention, "individual thickness" means the thickness of an individual sheet of tobacco material, and "combined thickness" means the total thickness of all sheets of tobacco material that make up the aerosol-generating substrate. For example, if the aerosol-generating substrate is formed from two separate sheets of tobacco material, the combined thickness is the sum of the thicknesses of the two separate sheets of tobacco material, or the measured thickness of the two sheets of tobacco material if the two sheets of tobacco material are laminated to the aerosol-generating substrate.

[0316] One or more sheets of tobacco material may each individually have a thickness of about 600 micrometers or less, about 300 micrometers or less, or about 250 micrometers or less.

[0317] One or more sheets of tobacco material may each individually have a thickness of from about 100 micrometers to about 600 micrometers, from about 100 micrometers to about 300 micrometers, or from about 100 micrometers to about 250 micrometers.

[0318] One or more sheets of tobacco material may each individually have a thickness of from about 150 micrometers to about 600 micrometers, from about 150 micrometers to about 300 micrometers, or from about 150 micrometers to about 250 micrometers.

[0319] One or more sheets of tobacco material may each individually have a thickness of from about 250 micrometers to about 600 micrometers, from about 250 micrometers to about 300 micrometers, or from about 250 micrometers to about 250 micrometers.

[0320] One or more sheets of tobacco material may each individually have a length that is substantially the same as the length of the aerosol-generating substrate.

[0321] One or more sheets of tobacco material may be subjected to one or more of crimping, folding, gathering, or pleating.

[0322] The curling, folding, gathering, or pleating of one or more sheets of tobacco material may cause the splitting of one or more sheets of tobacco material to form shreds of tobacco material. For example, one or more sheets of tobacco material may be curled to such an extent that the integrity of the one or more sheets of tobacco material is broken at a plurality of parallel ridges or corrugations, causing separation of the material and formation of shreds of tobacco material.

[0323] An aerosol-generating article may comprise a susceptor disposed within an aerosol-generating substrate.

[0324] As used herein with respect to the present invention, the term "susceptor" refers to a material capable of converting electromagnetic energy into heat. When positioned within a varying electromagnetic field, induced eddy currents in the susceptor cause heating of the susceptor.

[0325] The susceptor is disposed in thermal contact with the aerosol-generating substrate. Thus, when the susceptor is heated, the aerosol-generating substrate is heated by the susceptor and aerosol is generated. The susceptor may be disposed in direct physical contact with the aerosol-generating substrate.

[0326] The upstream element may advantageously prevent or limit upstream movement of the susceptor during storage, transportation, and use of the aerosol-generating article.

[0327] The susceptor may be an elongate susceptor.

[0328] As used herein with respect to the present invention, the term "elongate" is used to denote a component of an aerosol-generating article having a length greater than its width and thickness.

[0329] The elongated susceptor can be disposed substantially in the longitudinal direction within the aerosol generation substrate. That is, the longitudinal axis of the elongated susceptor may be substantially parallel to the longitudinal axis of the aerosol generation substrate. For example, the longitudinal axis of the elongated susceptor may have a parallelism within plus or minus 10 degrees with respect to the longitudinal axis of the aerosol generation substrate. The elongated susceptor is disposed at a radially central position within the aerosol generation substrate and can extend along the longitudinal axis of the aerosol generation substrate.

[0330] The susceptor may extend from the downstream end of the aerosol generation substrate toward the upstream end of the aerosol generation substrate.

[0331] The susceptor may extend from the upstream end of the aerosol generation substrate toward the downstream end of the aerosol generation substrate.

[0332] The susceptor may extend from the upstream end of the aerosol generation substrate to the downstream end of the aerosol generation substrate. That is, the susceptor may extend along the entire length of the aerosol generation substrate.

[0333] The length of the susceptor may be substantially the same as the length of the aerosol generation substrate.

[0334] The susceptor may extend partway along the length of the aerosol generation substrate.

[0335] The susceptor is spaced apart from the downstream end of the aerosol generation substrate.

[0336] The susceptor may be through a gap from the upstream end of the aerosol generation substrate.

[0337] The susceptor may be spaced apart from both the downstream end and the upstream end of the aerosol generation substrate.

[0338] The length of the susceptor may be shorter than the length of the aerosol generation substrate.

[0339] The susceptor can be completely enclosed within the aerosol generation substrate. That is, the aerosol generation substrate may completely surround the susceptor.

[0340] The susceptor can be in the form of pins, rods, flakes, or blades.

[0341] The susceptor may have a length of at least about 5 millimeters, at least about 6 millimeters, or at least about 8 millimeters.

[0342] The susceptor may have a length of about 15 millimeters or less, about 12 millimeters or less, or about 10 millimeters or less.

[0343] The susceptor may have a length of about 5 millimeters to about 15 millimeters, about 5 millimeters to about 12 millimeters, or about 5 millimeters to about 10 millimeters.

[0344] The susceptor may have a length of about 6 millimeters to about 15 millimeters, about 6 millimeters to about 12 millimeters, or about 6 millimeters to about 10 millimeters.

[0345] The susceptor may have a length of about 8 millimeters to about 15 millimeters, about 8 millimeters to about 12 millimeters, or about 8 millimeters to about 10 millimeters.

[0346] The susceptor may have a width of at least about 1 millimeter.

[0347] The susceptor may have a width of about 5 millimeters or less.

[0348] The susceptor may have a width of about 1 millimeter to about 5 millimeters.

[0349] The susceptor may have a thickness of at least about 0.01 millimeter to at least about 0.5 millimeter.

[0350] The susceptor may have a thickness of about 2 millimeters or less, about 500 micrometers or less, or about 100 micrometers or less.

[0351] The susceptor may have a thickness of about 10 micrometers to about 2 millimeters, about 10 micrometers to about 500 micrometers, or about 10 micrometers to about 100 micrometers.

[0352] The susceptor may have a thickness of about 0.5 millimeters to about 2 millimeters.

[0353] The susceptor may have a substantially circular cross-section. The susceptor may have a substantially constant cross-section along the length of the susceptor.

[0354] When the susceptor has the shape of a strip or blade, the strip or blade can have a rectangular shape with a width between about 2 millimeters and about 8 millimeters, or between about 3 millimeters and about 5 millimeters. As an example, the susceptor in the form of a blade strip may have a width of about 4 millimeters.

[0355] When the susceptor has the form of a strip or blade, the strip or blade can have a rectangular shape and a thickness of about 0.03 millimeters to about 0.15 millimeters, or about 0.05 millimeters to about 0.09 millimeters. As an example, the susceptor in the form of a blade strip may have a thickness of about 0.07 millimeters or 0.06 millimeters.

[0356] The susceptor may be formed from any material that can inductively heat it to a temperature sufficient to generate an aerosol from the aerosol-generating substrate. For example, the susceptor may contain metal or carbon.

[0357] The susceptor may include, or may be composed of, ferromagnetic materials (e.g., ferromagnetic alloys, ferrite iron, or ferromagnetic steel or ferromagnetic stainless steel). A suitable susceptor may be aluminum or may include aluminum. The susceptor may be formed from a 400 series stainless steel, such as grade 410, or grade 420, or grade 430 stainless steel. Different materials dissipate different amounts of energy when positioned within an electromagnetic field having similar values of frequency and magnetic field strength.

[0358] Thus, all of the susceptor parameters, such as the type, length, width, and thickness of the material, may be modified to provide the desired power dissipation within a known electromagnetic field. The susceptor may be heated to a temperature exceeding 250 °C.

[0359] A suitable susceptor may comprise a non-metallic core having a metal layer disposed thereon (e.g., a track of metal formed on the surface of a ceramic core). The susceptor may have a protective outer layer encapsulating the susceptor, such as a protective ceramic layer or a protective glass layer. The susceptor may include a protective coating formed of glass, ceramic, or an inert metal, formed to cover the core of the susceptor material.

[0360] The susceptor may be a multi-material susceptor and may include a first susceptor material and a second susceptor material.

[0361] The aerosol generating article may comprise a mouthpiece element located downstream of the aerosol generating substrate.

[0362] The mouthpiece element may be located at the mouth-side or downstream end of the aerosol generating article.

[0363] The mouthpiece element may be a mouthpiece filter element. The mouthpiece element may comprise at least one filter segment for filtering the aerosol generated during heating of the aerosol-generating substrate. For example, the mouthpiece element may comprise one or more segments of fibrous filter material. Suitable fibrous filter materials are well known in the art. For example, at least one mouthpiece filter segment may comprise a cellulose acetate filter segment formed from cellulose acetate tow.

[0364] The mouthpiece element may be composed of a single filter segment. The mouthpiece element may comprise two or more filter segments that are axially aligned in an end-to-end abutting relationship with each other.

[0365] The mouthpiece element may contain a flavorant provided in a suitable form. For example, the mouthpiece element may contain one or more capsules, flavorant beads or granules, or one or more flavor-loaded threads or filaments.

[0366] The parameters or characteristics described herein in relation to the entire mouthpiece element may equally apply to the filter segments of the mouthpiece element.

[0367] The mouthpiece element may have a low particulate filtration efficiency.

[0368] The mouthpiece element may have an RTD of about 25 millimeters of H2O or less, about 20 millimeters of H2O or less, or about 15 millimeters of H2O or less.

[0369] The mouthpiece element may have an RTD of at least about 10 millimeters of H2O or less.

[0370] The mouthpiece element may have an RTD of about 10 millimeters H2O to about 25 millimeters H2O, about 10 millimeters H2O to about 20 millimeters H2O, or about 10 millimeters H2O to about 15 millimeters H2O.

[0371] The mouthpiece element preferably has a substantially circular cross-section.

[0372] Preferably, the mouthpiece element has an outer diameter that is substantially the same as the outer diameter of the aerosol-generating article.

[0373] The mouthpiece element may have a length of at least 3 millimeters or 5 millimeters.

[0374] The length of the mouthpiece element may be about 11 millimeters or less, or about 9 millimeters or less.

[0375] The mouthpiece element may have a length of about 3 millimeters to about 11 millimeters, or about 3 millimeters to about 9 millimeters.

[0376] The mouthpiece element may have a length of about 5 millimeters to about 11 millimeters, or about 5 millimeters to about 9 millimeters.

[0377] For example, the length of the mouthpiece element may be about 7 millimeters.

[0378] The length of the mouthpiece element may be selected based on the desired overall length of the aerosol-generating article.

[0379] The mouthpiece element may be surrounded by a plug wrap.

[0380] The mouthpiece element may not be ventilated so that air does not enter the aerosol-generating article along the mouthpiece element.

[0381] The mouthpiece element may be connected by a tipping wrapper to one or more of the adjacent components of the aerosol-generating article.

[0382] The aerosol-generating article may include a mouth-side end cavity located at the downstream end of the aerosol-generating article. The mouth-side end cavity, if present, may be disposed downstream of the mouthpiece element.

[0383] The mouth-side end cavity may be defined by a hollow tubular element provided at the downstream end of the mouthpiece. Alternatively, the mouth-side end cavity may be defined by an outer wrapper of the mouthpiece element, where the outer wrapper extends in the downstream direction from the mouthpiece element.

[0384] The aerosol-generating article may include one or more intermediate elements between the aerosol-generating substrate and the mouthpiece element. The one or more intermediate elements may abut against each other in an end-to-end contact relationship.

[0385] One of the one or more intermediate elements may abut against the downstream end of the aerosol-generating substrate. One of the one or more intermediate elements may abut against the upstream end of the mouthpiece element. For example, if there is a single intermediate element, the single intermediate element may abut against both the downstream end of the aerosol-generating substrate and the upstream end of the mouthpiece element. For example, if there are a plurality of intermediate elements, one intermediate element may abut against the downstream end of the aerosol-generating substrate and another intermediate element may abut against the upstream end of the mouthpiece element.

[0386] At least one of the one or more intermediate elements may be a hollow tubular element. The one or more intermediate elements may be one or more hollow tubular elements.

[0387] As used herein in connection with the present invention, the term "hollow tubular element" is used to represent a generally cylindrical element having a tubular space along its longitudinal axis. The hollow tubular element may have a substantially circular, substantially oval, or substantially elliptical cross-section. The tubular space may have a substantially circular, substantially oval, or substantially elliptical cross-section. Specifically, the term "tubular" is used to represent an element that defines at least one air flow conduit establishing unbroken fluid communication between the upstream end of the hollow tubular element and the downstream end of the hollow tubular element.

[0388] In the context of the present invention, the hollow tubular element provides an unobstructed flow channel. This means that the hollow tubular element provides a negligible level of pull-out resistance (RTD). As used herein in connection with the present invention, the term "negligible level of RTD" is used to represent an RTD of less than 1 mmH2O per 10 millimeters of the length of the hollow tubular element, less than 0.4 mmH2O per 10 millimeters of the length of the hollow tubular element, or less than 0.1 mmH2O per 10 millimeters of the length of the hollow tubular element. Accordingly, the flow channel should not comprise any component that would impede the longitudinal air flow. Preferably, the flow channel is substantially empty.

[0389] One or more intermediate elements may have an overall length of at least about 10 millimeters, at least about 12 millimeters, or at least about 15 millimeters.

[0390] One or more intermediate elements may have an overall length of about 30 millimeters or less, about 25 millimeters or less, or about 23 millimeters or less.

[0391] One or more intermediate elements may have an overall length of from about 10 millimeters to about 30 millimeters, from about 10 millimeters to about 25 millimeters, or from about 10 millimeters to about 23 millimeters.

[0392] One or more intermediate elements may have an overall length of from about 12 millimeters to about 30 millimeters, from about 12 millimeters to about 25 millimeters, or from about 12 millimeters to about 23 millimeters.

[0393] One or more intermediate elements may have an overall length of from about 12 millimeters to about 30 millimeters, from about 12 millimeters to about 25 millimeters, or from about 12 millimeters to about 23 millimeters.

[0394] The overall length of one or more intermediate elements may be selected based on the desired overall length of the aerosol-generating article.

[0395] When the aerosol-generating article comprises a single intermediate element, the overall length of one or more intermediate elements is the length of the single intermediate element. When the aerosol-generating article comprises a plurality of intermediate elements, the overall length of one or more intermediate elements is the sum of the lengths of each of the plurality of intermediate elements.

[0396] When the aerosol-generating article comprises a plurality of intermediate elements, the length of each of the plurality of intermediate elements may be substantially the same.

[0397] Each of the one or more intermediate elements preferably has a substantially circular cross-section.

[0398] Preferably, the outer diameter of each of the one or more intermediate elements is substantially the same as the outer diameter of the aerosol-generating article.

[0399] One or more intermediate elements can be formed from any suitable material or combination of materials. For example, at least one of the one or more intermediate elements can be formed from one or more materials selected from the group consisting of cellulose acetate; paper-based materials such as paper or cardboard, and polymeric materials such as low density polyethylene (LDPE). Other suitable materials include polyhydroxyalkanoate (PHA) fibers.

[0400] The ventilation zone may be provided at a location along one or more intermediate elements. Satisfactory cooling of the aerosol flow generated with the heating of the aerosol generating substrate and drawn through one or more intermediate elements can be achieved by providing a ventilation zone at a location along one or more intermediate elements. Without wishing to be bound by any theory, the temperature drop caused by the entry of cold outside air through the ventilation zone into one or more intermediate elements may have an advantageous effect on the nucleation and growth of aerosol particles.

[0401] The ventilation zone may be provided at a location along at least one of the one or more intermediate elements.

[0402] When the intermediate element is a hollow tubular element, the ventilation zone may comprise a plurality of perforations passing through at least one tubular wall of the one or more hollow tubular elements. The ventilation zone may comprise at least one circumferential row of perforations. 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. Each circumferential row of perforations includes 8 to 30 perforations.

[0403] The aerosol generating article may have an overall length of at least about 35 millimeters, at least about 38 millimeters, at least about 40 millimeters, or at least about 42 millimeters.

[0404] The aerosol generating article may have an overall length of about 100 millimeters or less, about 70 millimeters or less, about 60 millimeters or less, or 50 millimeters or less.

[0405] The aerosol generating article may have an overall length of about 35 millimeters to about 100 millimeters, about 35 millimeters to about 70 millimeters, about 35 millimeters to about 60 millimeters, or about 35 millimeters to about 50 millimeters.

[0406] The aerosol generating article may have an overall length of about 38 millimeters to about 100 millimeters, about 38 millimeters to about 70 millimeters, about 38 millimeters to about 60 millimeters, or about 38 millimeters to about 50 millimeters.

[0407] The aerosol generating article may have an overall length of about 40 millimeters to about 100 millimeters, about 40 millimeters to about 70 millimeters, about 40 millimeters to about 60 millimeters, or about 40 millimeters to about 50 millimeters.

[0408] The aerosol generating article may have an overall length of about 42 millimeters to about 100 millimeters, about 42 millimeters to about 70 millimeters, about 42 millimeters to about 60 millimeters, or about 42 millimeters to about 50 millimeters. For example, the aerosol generating article may have an overall length of about 45 millimeters.

[0409] The aerosol generating article preferably has a substantially circular cross-section.

[0410] The aerosol generating article may have an outer diameter of at least about 5 millimeters, at least about 6 millimeters, or at least about 7 millimeters.

[0411] The aerosol generating article may have an outer diameter of about 12 millimeters or less, about 10 millimeters or less, or about 8 millimeters or less.

[0412] The aerosol generating article may have an outer diameter of about 5 millimeters to about 12 millimeters, or about 5 millimeters to about 10 millimeters, or about 5 millimeters to about 8 millimeters.

[0413] The aerosol generating article may have an outer diameter of about 6 millimeters to about 12 millimeters, or about 6 millimeters to about 10 millimeters, or about 6 millimeters to about 8 millimeters.

[0414] The aerosol generating article may have an outer diameter of about 7 millimeters to about 12 millimeters, or about 7 millimeters to about 10 millimeters, or about 7 millimeters to about 8 millimeters.

[0415] For example, the aerosol generating article may have an outer diameter of about 7.1 millimeters.

[0416] According to a second aspect of the present invention, there is provided an aerosol generation system comprising an aerosol generating article according to a first aspect of the present invention and an aerosol generation device configured to heat the aerosol generation matrix of the aerosol generating article, the aerosol generation device comprising a housing defining a cavity configured to receive the aerosol generating article.

[0417] The aerosol generation device may be a handheld aerosol generation device.

[0418] The aerosol generation device may also be an electrically operated aerosol generation device.

[0419] The aerosol generation device may include a power source and control electronics.

[0420] The aerosol generation device may include a battery and control electronics.

[0421] The aerosol generation device may be configured to heat the aerosol generation matrix of the aerosol generating article from the outside. That is, the aerosol generation device may be configured to heat the aerosol generation matrix of the aerosol generating article from the outside of the aerosol generation matrix of the aerosol generating article.

[0422] The aerosol generation device may include a heating element, for example, an external heating element.

[0423] The heating element may be disposed around the cavity.

[0424] The heating element may include one or both of a resistive heating element and an inductive heating element.

[0425] The aerosol generating device may include a mouthpiece.

[0426] The following is 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, or embodiment, or aspect described herein.

[0427] [Example 1] An aerosol generating article comprising an aerosol generating substrate and an upstream element provided upstream of the aerosol generating substrate, the upstream element comprising a tubular portion defining an inner region of the upstream element and a spiral sheet defining a plurality of channels extending in the longitudinal direction within the inner region.

[0428] [Example 2] The aerosol generating article according to Example 1, wherein the spiral sheet comprises a plurality of non-concentric turns.

[0429] [Example 3] The aerosol generating article according to Example 1 or 2, wherein the spiral sheet is one or more of crimped, folded, gathered, and pleated to define a plurality of channels extending in the longitudinal direction.

[0430] [Example 4] The aerosol generating article according to any one of Examples 1 to 3, wherein the spiral sheet is crimped.

[0431] [Example 5] The aerosol generating article according to any one of Examples 1 to 4, wherein the spiral sheet has a plurality of substantially parallel ridges or corrugations extending in the longitudinal direction of the aerosol generating article.

[0432] [Example 6] The aerosol generating article according to Example 5, wherein adjacent ridges or corrugations are spaced from each other by about 1.2 millimeters or less.

[0433] [Example 7] The aerosol generating article according to Example 5 or Example 6, wherein adjacent raised portions or corrugated portions are spaced apart from each other by about 1 millimeter or less.

[0434] [Example 8] The aerosol generating article according to any one of Examples 4 to 7, wherein adjacent raised portions or corrugated portions are spaced apart from each other by about 0.8 millimeter or less.

[0435] [Example 9] The aerosol generating article according to any one of Examples 4 to 8, wherein adjacent raised portions or corrugated portions are spaced apart from each other by about 0.5 millimeter or less.

[0436] [Example 10] The aerosol generating article according to any one of Examples 1 to 9, wherein the spiral sheet is an aggregate of curled sheets.

[0437] [Example 11] The aerosol generating article according to any one of Examples 1 to 10, wherein the spiral sheet extends from the downstream end of the upstream element toward the upstream end of the upstream element.

[0438] [Example 12] The aerosol generating article according to any one of Examples 1 to 11, wherein the spiral sheet extends from the upstream end of the upstream element toward the downstream end of the upstream element.

[0439] [Example 13] The aerosol generating article according to any one of Examples 1 to 12, wherein the length of the spiral sheet is substantially the same as the length of the upstream element.

[0440] [Example 14] The aerosol generating article according to any one of Examples 1 to 13, wherein the plurality of channels extending in the major axis direction extend from the downstream end of the upstream element toward the upstream end of the upstream element.

[0441] [Example 15] The aerosol generating article according to any one of Examples 1 to 14, wherein a plurality of channels extending in the major axis direction extend from the upstream end of the upstream element to the downstream end of the upstream element.

[0442] [Example 16] The aerosol generating article according to any one of Examples 1 to 15, wherein the spiral sheet has a basis weight of about 100 g / m² or less.

[0443] [Example 17] The aerosol generating article according to any one of Examples 1 to 16, wherein the spiral sheet has a basis weight of about 80 g / m² or less.

[0444] [Example 18] The aerosol generating article according to any one of Examples 1 to 17, wherein the spiral sheet has a basis weight of about 70 g / m² or less.

[0445] [Example 19] The aerosol generating article according to any one of Examples 1 to 18, wherein the spiral sheet has a basis weight of about 50 g / m² or less.

[0446] [Example 20] The aerosol generating article according to any one of Examples 1 to 19, wherein the spiral sheet has a basis weight of at least about 10 g / m² or less.

[0447] [Example 21] The aerosol generating article according to any one of Examples 1 to 20, wherein the spiral sheet has a basis weight of at least about 15 g / m² or less.

[0448] [Example 22] The aerosol generating article according to any one of Examples 1 to 21, wherein the spiral sheet has a basis weight of at least about 20 g / m² or less.

[0449] [Example 23] The aerosol-generating article according to any one of Examples 1 to 22, wherein the spiral sheet has a weight of at least about 10 milligrams.

[0450] [Example 24] The aerosol-generating article according to any one of Examples 1 to 23, wherein the spiral sheet has a weight of at least about 15 milligrams.

[0451] [Example 25] The aerosol-generating article according to any one of Examples 1 to 24, wherein the spiral sheet has a weight of at least about 20 milligrams.

[0452] [Example 26] The aerosol-generating article according to any one of Examples 1 to 25, wherein the spiral sheet has a weight of about 100 milligrams or less.

[0453] [Example 27] The aerosol-generating article according to any one of Examples 1 to 26, wherein the spiral sheet has a weight of about 75 milligrams or less.

[0454] [Example 28] The aerosol-generating article according to any one of Examples 1 to 27, wherein the spiral sheet has a weight of about 50 milligrams or less.

[0455] [Example 29] The aerosol-generating article according to any one of Examples 1 to 28, wherein the spiral sheet has an average weight per unit length of about 20 milligrams / millimeter or less.

[0456] [Example 30] The aerosol-generating article according to any one of Examples 1 to 29, wherein the spiral sheet has an average weight per unit length of about 15 milligrams / millimeter or less.

[0457] [Example 31] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 30, having an average weight per unit length of about 10 milligrams / millimeter or less.

[0458] [Example 32] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 31, having an average weight per unit length of at least about 2 milligrams / millimeter.

[0459] [Example 33] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 32, having an average weight per unit length of at least about 3 milligrams / millimeter.

[0460] [Example 34] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 33, having an average weight per unit length of at least about 4 milligrams / millimeter.

[0461] [Example 35] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 34, having an average weight per unit volume of the inner region of about 500 micrograms / cubic millimeter or less.

[0462] [Example 36] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 35, having an average weight per unit volume of the inner region of about 400 micrograms / cubic millimeter or less.

[0463] [Example 37] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 36, having an average weight per unit volume of the inner region of about 250 micrograms / cubic millimeter or less.

[0464] [Example 38] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 37, having an average weight per unit volume of the inner region of at least about 50 micrograms per cubic millimeter.

[0465] [Example 39] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 38, having an average weight per unit volume of the inner region of at least about 75 micrograms per cubic millimeter.

[0466] [Example 40] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 39, having an average weight per unit volume of the inner region of at least about 100 micrograms per cubic millimeter.

[0467] [Example 41] The sheet is an aerosol generating article according to any one of Examples 1 to 40, having a thickness of about 300 micrometers or less.

[0468] [Example 42] The sheet is an aerosol generating article according to any one of Examples 1 to 41, having a thickness of about 200 micrometers or less.

[0469] [Example 43] The sheet is an aerosol generating article according to any one of Examples 1 to 42, having a thickness of about 150 micrometers or less.

[0470] [Example 44] The sheet is an aerosol generating article according to any one of Examples 1 to 43, having a thickness of at least about 30 micrometers.

[0471] [Example 45] The sheet is an aerosol generating article according to any one of Examples 1 to 45, having a thickness of at least about 45 micrometers.

[0472] [Example 46] The sheet is an aerosol generating article according to any one of Examples 1 to 45, having a thickness of at least about 60 micrometers.

[0473] [Example 47] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 46, having a cross-sectional area of at least about 5 square millimeters.

[0474] [Example 48] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 47, having a cross-sectional area of at least about 8 square millimeters.

[0475] [Example 49] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 48, having a cross-sectional area of at least about 10 square millimeters.

[0476] [Example 50] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 49, having a cross-sectional area of about 30 square millimeters or less.

[0477] [Example 51] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 50, having a cross-sectional area of about 25 square millimeters or less.

[0478] [Example 52] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 51, having a cross-sectional area of about 20 square millimeters or less.

[0479] [Example 53] The cross-sectional area of the spiral sheet is substantially constant along the length of the spiral sheet, and it is an aerosol generating article according to any one of Examples 1 to 52.

[0480] [Example 54] An aerosol generating article according to any one of Examples 1 to 53, wherein the spiral sheet has a surface area of at least about 250 square millimeters.

[0481] [Example 55] An aerosol generating article according to any one of Examples 1 to 54, wherein the spiral sheet has a surface area of at least about 400 square millimeters.

[0482] [Example 56] An aerosol generating article according to any one of Examples 1 to 55, wherein the spiral sheet has a surface area of at least about 600 square millimeters.

[0483] [Example 57] An aerosol generating article according to any one of Examples 1 to 56, wherein the spiral sheet has a surface area of about 1500 square millimeters or less.

[0484] [Example 58] An aerosol generating article according to any one of Examples 1 to 57, wherein the spiral sheet has a surface area of about 1350 square millimeters or less.

[0485] [Example 59] An aerosol generating article according to any one of Examples 1 to 58, wherein the spiral sheet has a surface area of about 1250 square millimeters or less.

[0486] [Example 60] An aerosol generating article according to any one of Examples 1 to 59, wherein the spiral sheet has an average surface area of at least about 50 square millimeters per millimeter of unit length.

[0487] [Example 61] An aerosol generating article according to any one of Examples 1 to 60, wherein the spiral sheet has an average surface area of at least about 80 square millimeters per millimeter of unit length.

[0488] [Example 62] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 61, having an average surface area of at least about 120 square millimeters per millimeter of unit length.

[0489] [Example 63] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 62, having an average surface area of about 300 square millimeters per millimeter or less of unit length.

[0490] [Example 64] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 63, having an average surface area of about 270 square millimeters per millimeter or less of unit length.

[0491] [Example 65] The spiral sheet is an aerosol generating article according to any one of Examples 1 to 64, having an average surface area of about 250 square millimeters per millimeter or less of unit length.

[0492] [Example 66] The aerosol generating article according to any one of Examples 1 to 65, wherein the spiral sheet has a length of at least about 2 millimeters.

[0493] [Example 67] The aerosol generating article according to any one of Examples 1 to 66, wherein the spiral sheet has a length of at least about 3 millimeters.

[0494] [Example 68] The aerosol generating article according to any one of Examples 1 to 67, wherein the spiral sheet has a length of at least about 4 millimeters.

[0495] [Example 69] The aerosol generating article according to any one of Examples 1 to 68, wherein the spiral sheet has a length of about 10 millimeters or less.

[0496] [Example 70] An aerosol generating article according to any one of Examples 1 to 69, wherein the spiral sheet has a length of about 8 millimeters or less.

[0497] [Example 71] An aerosol generating article according to any one of Examples 1 to 70, wherein the spiral sheet has a length of about 6 millimeters or less.

[0498] [Example 72] An aerosol generating article according to any one of Examples 1 to 71, wherein the spiral sheet has a length of about 5 millimeters.

[0499] [Example 73] An aerosol generating article according to any one of Examples 1 to 72, wherein the sheet has a width of at least about 50 millimeters.

[0500] [Example 74] An aerosol generating article according to any one of Examples 1 to 73, wherein the sheet has a width of at least about 80 millimeters.

[0501] [Example 75] An aerosol generating article according to any one of Examples 1 to 74, wherein the sheet has a width of at least about 120 millimeters.

[0502] [Example 76] An aerosol generating article according to any one of Examples 1 to 75, wherein the sheet has a width of about 300 millimeters or less.

[0503] [Example 77] An aerosol generating article according to any one of Examples 1 to 76, wherein the sheet has a width of about 270 millimeters or less.

[0504] [Example 78] An aerosol generating article according to any one of Examples 1 to 77, wherein the sheet has a width of about 250 millimeters or less.

[0505] [Example 79] An aerosol generating article according to any one of Examples 1 to 78, wherein the sheet has a linear shrinkage rate of about 4% or less.

[0506] [Example 80] An aerosol generating article according to any one of Examples 1 to 79, wherein the sheet has a linear shrinkage rate of about 3% or less.

[0507] [Example 81] An aerosol generating article according to any one of Examples 1 to 80, wherein the sheet has a linear shrinkage rate of about 2% or less.

[0508] [Example 82] An aerosol generating article according to any one of Examples 1 to 81, wherein the sheet has a linear shrinkage rate of about 1.5% or less.

[0509] [Example 83] An aerosol generating article according to any one of Examples 1 to 82, wherein the sheet has a linear shrinkage rate of about 1% or less.

[0510] [Example 84] An aerosol generating article according to any one of Examples 1 to 83, wherein the sheet has a linear shrinkage rate of about 0.5% or less.

[0511] [Example 85] An aerosol generating article according to any one of Examples 1 to 84, wherein the sheet has an area shrinkage rate of about 8% or less.

[0512] [Example 86] An aerosol generating article according to any one of Examples 1 to 85, wherein the sheet has an area shrinkage rate of about 6% or less.

[0513] [Example 87] An aerosol generating article according to any one of Examples 1 to 86, wherein the sheet has an area shrinkage rate of about 3% or less.

[0514] [Example 88] An aerosol generating article according to any one of Examples 1 to 87, wherein the sheet has an area shrinkage rate of about 2% or less.

[0515] [Example 89] An aerosol generating article according to any one of Examples 1 to 88, wherein the sheet has an area shrinkage rate of about 1.5% or less.

[0516] [Example 90] An aerosol generating article according to any one of Examples 1 to 89, wherein the sheet has an area shrinkage rate of about 1% or less.

[0517] [Example 91] An aerosol generating article according to any one of Examples 1 to 89, wherein the spiral sheet is formed from a paper-based material such as paper or cardboard.

[0518] [Example 92] An aerosol generating article according to any one of Examples 1 to 88, wherein the spiral sheet is formed from polylactic acid.

[0519] [Example 93] An aerosol generating article according to any one of Examples 1 to 92, wherein the spiral sheet contains a flame retardant coating.

[0520] [Example 94] An aerosol generating article according to any one of Examples 1 to 93, wherein the plurality of channels extending in the major axis direction are empty.

[0521] [Example 95] An aerosol generating article according to any one of Examples 1 to 94, wherein the plurality of channels extending in the major axis direction includes at least five channels extending in the major axis direction.

[0522] [Example 96] The aerosol generating article according to any one of Examples 1 to 95, wherein the plurality of channels extending in the major axis direction includes at least 10 channels extending in the major axis direction.

[0523] [Example 97] The aerosol generating article according to any one of Examples 1 to 96, wherein the plurality of channels extending in the major axis direction includes at least 20 channels extending in the major axis direction.

[0524] [Example 98] The aerosol generating article according to any one of Examples 1 to 97, wherein the plurality of channels extending in the major axis direction includes at least 30 channels extending in the major axis direction.

[0525] [Example 99] The aerosol generating article according to any one of Examples 1 to 98, wherein the plurality of channels extending in the major axis direction has a maximum width of about 5 millimeters or less.

[0526] [Example 100] The aerosol generating article according to any one of Examples 1 to 99, wherein the plurality of channels extending in the major axis direction has a maximum width of about 4 millimeters or less.

[0527] [Example 101] The aerosol generating article according to any one of Examples 1 to 100, wherein the plurality of channels extending in the major axis direction has a maximum width of about 3 millimeters or less.

[0528] [Example 102] The aerosol generating article according to any one of Examples 1 to 101, wherein the plurality of channels extending in the major axis direction has a maximum cross-sectional area of about 4 square millimeters or less.

[0529] [Example 103] The aerosol generating article according to any one of Examples 1 to 102, wherein the plurality of channels extending in the major axis direction has a maximum cross-sectional area of about 3 square millimeters or less.

[0530] [Example 104] The aerosol generating article according to any one of Examples 1 to 103, wherein a plurality of channels extending in the major axis direction have a maximum cross-sectional area of about 2 square millimeters or less.

[0531] [Example 105] The aerosol generating article according to any one of Examples 1 to 104, wherein a plurality of channels extending in the major axis direction have an average width of about 4 millimeters or less.

[0532] [Example 106] The aerosol generating article according to any one of Examples 1 to 105, wherein a plurality of channels extending in the major axis direction have an average width of about 3 millimeters or less.

[0533] [Example 107] The aerosol generating article according to any one of Examples 1 to 106, wherein a plurality of channels extending in the major axis direction have an average width of about 2 millimeters or less.

[0534] [Example 108] The aerosol generating article according to any one of Examples 1 to 107, wherein a plurality of channels extending in the major axis direction have an average cross-sectional area of about 3 millimeters or less.

[0535] [Example 109] The aerosol generating article according to any one of Examples 1 to 108, wherein a plurality of channels extending in the major axis direction have an average cross-sectional area of about 2 millimeters or less.

[0536] [Example 110] The aerosol generating article according to any one of Examples 1 to 109, wherein a plurality of channels extending in the major axis direction have an average cross-sectional area of about 1 millimeter or less.

[0537] [Example 111] The aerosol generating article according to any one of Examples 1 to 110, wherein the ratio of the maximum width of a plurality of channels extending in the major axis direction to the length of the spiral sheet is about 1 or less.

[0538] [Example 112] An aerosol generating article according to any one of Examples 1 to 111, wherein the ratio of the maximum width of the plurality of channels extending in the major axis direction to the length of the spiral sheet is about 0.8 or less.

[0539] [Example 113] An aerosol generating article according to any one of Examples 1 to 112, wherein the ratio of the maximum width of the plurality of channels extending in the major axis direction to the length of the spiral sheet is about 0.6 or less.

[0540] [Example 114] An aerosol generating article according to any one of Examples 1 to 113, wherein the ratio of the maximum cross-sectional area of the plurality of channels extending in the major axis direction to the length of the spiral sheet is about 0.8 or less.

[0541] [Example 115] An aerosol generating article according to any one of Examples 1 to 114, wherein the ratio of the maximum cross-sectional area of the plurality of channels extending in the major axis direction to the length of the spiral sheet is about 0.6 or less.

[0542] [Example 116] An aerosol generating article according to any one of Examples 1 to 115, wherein the ratio of the maximum cross-sectional area of the plurality of channels extending in the major axis direction to the length of the spiral sheet is about 0.4 or less.

[0543] [Example 117] An aerosol generating article according to any one of Examples 1 to 116, wherein the ratio of the average width of the plurality of channels extending in the major axis direction to the length of the spiral sheet is about 0.8 or less.

[0544] [Example 118] An aerosol generating article according to any one of Examples 1 to 117, wherein the ratio of the average width of the plurality of channels extending in the major axis direction to the length of the spiral sheet is about 0.6 or less.

[0545] [Example 119] The aerosol generating article according to any one of Examples 1 to 118, wherein the ratio of the average width of the plurality of channels extending in the major axis direction to the length of the spiral sheet is about 0.4 or less.

[0546] [Example 120] The aerosol generating article according to any one of Examples 1 to 119, wherein the ratio of the average cross-sectional area of the plurality of channels extending in the major axis direction to the length of the spiral sheet is about 0.6 or less.

[0547] [Example 121] The aerosol generating article according to any one of Examples 1 to 120, wherein the ratio of the average cross-sectional area of the plurality of channels extending in the major axis direction to the length of the spiral sheet is about 0.4 or less.

[0548] [Example 122] The aerosol generating article according to any one of Examples 1 to 121, wherein the ratio of the average cross-sectional area of the plurality of channels extending in the major axis direction to the length of the spiral sheet is about 0.2 or less.

[0549] [Example 123] The aerosol generating article according to any one of Examples 1 to 122, wherein the total cross-sectional area of the plurality of channels is substantially constant along the entire length of the spiral sheet.

[0550] [Example 124] The aerosol generating article according to any one of Examples 1 to 122, wherein the upstream element comprises a tubular portion and a spiral sheet.

[0551] [Example 125] The aerosol generating article according to any one of Examples 1 to 124, wherein the tubular portion is formed by a wrapper surrounding the spiral sheet.

[0552] [Example 126] The aerosol generating article according to any one of Examples 1 to 125, wherein the length of the tubular portion is the same as the length of the upstream element.

[0553] [Example 127] An aerosol-generating article according to any one of Examples 1 to 126, wherein the RTD of the upstream element per unit length is at least about 0.2 millimeters H2O.

[0554] [Example 128] An aerosol-generating article according to any one of Examples 1 to 127, wherein the RTD of the upstream element per unit length is at least about 0.5 millimeters H2O.

[0555] [Example 129] An aerosol-generating article according to any one of Examples 1 to 128, wherein the RTD of the upstream element per unit length is at least about 2 millimeters H2O.

[0556] [Example 130] An aerosol-generating article according to any one of Examples 1 to 129, wherein the RTD of the upstream element per unit length is about 3 millimeters H2O or less.

[0557] [Example 131] An aerosol-generating article according to any one of Examples 1 to 130, wherein the RTD of the upstream element per unit length is about 2.5 millimeters H2O or less.

[0558] [Example 132] An aerosol-generating article according to any one of Examples 1 to 131, wherein the RTD of the upstream element per unit length is about 2 millimeters H2O or less.

[0559] [Example 133] An aerosol-generating article according to any one of Examples 1 to 132, wherein the RTD of the upstream element per unit length is about 1.5 millimeters H2O.

[0560] [Example 134] An aerosol-generating article according to any one of Examples 1 to 133, wherein the RTD of the upstream element is at least about 1 millimeter H2O.

[0561] [Example 135] The aerosol-generating article according to any one of Examples 1 to 134, wherein the RTD of the upstream element is at least about 2.5 millimeters of H2O.

[0562] [Example 136] The aerosol-generating article according to any one of Examples 1 to 135, wherein the RTD of the upstream element is at least about 5 millimeters of H2O.

[0563] [Example 137] The aerosol-generating article according to any one of Examples 1 to 136, wherein the RTD of the upstream element is about 15 millimeters of H2O or less.

[0564] [Example 138] The aerosol-generating article according to any one of Examples 1 to 137, wherein the RTD of the upstream element is about 12.5 millimeters of H2O or less.

[0565] [Example 139] The aerosol-generating article according to any one of Examples 1 to 138, wherein the RTD of the upstream element is about 10 millimeters of H2O or less.

[0566] [Example 140] The aerosol-generating article according to any one of Examples 1 to 138, wherein the RTD of the upstream element is about 7.5 millimeters of H2O.

[0567] [Example 141] The aerosol-generating article according to any one of Examples 1 to 140, wherein the ratio of the RTD of the upstream element to the overall RTD of the aerosol-generating article is less than 0.5.

[0568] [Example 142] The aerosol-generating article according to any one of Examples 1 to 141, wherein the ratio of the RTD of the upstream element to the overall RTD of the aerosol-generating article is at least about 0.01.

[0569] [Example 143] An aerosol-generating article according to any one of Examples 1 to 142, wherein the upstream element has a porosity of at least about 40 percent.

[0570] [Example 144] An aerosol-generating article according to any one of Examples 1 to 143, wherein the upstream element has a porosity of at least about 45 percent.

[0571] [Example 145] An aerosol-generating article according to any one of Examples 1 to 144, wherein the upstream element has a porosity of at least about 50 percent.

[0572] [Example 146] An aerosol-generating article according to any one of Examples 1 to 145, wherein the upstream element has a porosity of about 85 percent or less.

[0573] [Example 147] An aerosol-generating article according to any one of Examples 1 to 146, wherein the upstream element has a porosity of about 80 percent or less.

[0574] [Example 148] An aerosol-generating article according to any one of Examples 1 to 147, wherein the upstream element has a porosity of about 75 percent or less.

[0575] [Example 149] An aerosol-generating article according to any one of Examples 1 to 148, wherein the aerosol-generating article has a hardness of at least about 80 percent in the upstream element.

[0576] [Example 150] An aerosol-generating article according to any one of Examples 1 to 149, wherein the upstream element has a length of at least about 2 millimeters.

[0577] [Example 152] An aerosol-generating article according to any one of Examples 1 to 150, wherein the upstream element has a length of about 10 millimeters or less.

[0578] [Example 153] The aerosol generating article according to any one of Examples 1 to 152, wherein the ratio of the length of the upstream element to the total length of the aerosol generating article is at least about 0.03.

[0579] [Example 154] The aerosol generating article according to any one of Examples 1 to 152, wherein the ratio of the length of the upstream element to the total length of the aerosol generating article is about 0.25 or less.

[0580] [Example 155] The aerosol generating article according to any one of Examples 1 to 154, wherein the outer diameter of the upstream element is substantially the same as the outer diameter of the aerosol generating article.

[0581] [Example 155] The aerosol generating article according to any one of Examples 1 to 154, wherein the upstream element is adjacent to the aerosol generating substrate.

[0582] [Example 156] The aerosol generating article according to any one of Examples 1 to 155, wherein the upstream element is provided at the upstream end of the aerosol generating article.

[0583] [Example 157] The aerosol generating article according to any one of Examples 1 to 155, further comprising an additional element upstream of the upstream element.

[0584] [Example 158] The aerosol generating article according to any one of Examples 1 to 157, wherein the upstream element contains about 1 weight percent or less of an aerosol forming agent on a dry weight basis.

[0585] [Example 159] The aerosol generating article according to any one of Examples 1 to 157, wherein the upstream element substantially does not contain an aerosol forming agent.

[0586] [Example 160] An aerosol-generating article according to any one of Examples 1 to 159, wherein the ratio of the weight of the aerosol-forming substance in the upstream element to the weight of the aerosol-forming substance in the aerosol-generating substrate, both based on the dry weight of the upstream element, is about 0.2 or less.

[0587] [Example 161] An aerosol-generating article according to any one of Examples 1 to 160, wherein the aerosol-generating substrate has a density of at least about 150 milligrams per cubic centimeter.

[0588] [Example 162] An aerosol-generating article according to any one of Examples 1 to 161, wherein the aerosol-generating substrate has a density of about 500 milligrams per cubic centimeter or less.

[0589] [Example 163] An aerosol-generating article according to any one of Examples 1 to 162, wherein the aerosol-generating substrate contains an aerosol-forming substance.

[0590] [Example 164] An aerosol-generating article according to any one of Examples 1 to 163, wherein the aerosol-generating substrate contains a plurality of shreds of tobacco material.

[0591] [Example 165] An aerosol-generating article according to any one of Examples 1 to 164, wherein the aerosol-generating substrate contains tobacco cut filler.

[0592] [Example 166] An aerosol-generating article according to any one of Examples 1 to 165, wherein the aerosol-generating substrate contains a plurality of shreds of homogenized tobacco material.

[0593] [Example 167] An aerosol-generating article according to any one of Examples 164 to 166, wherein the shreds of tobacco material have a width of at least about 0.3 millimeters.

[0594] [Example 168] An aerosol generating article according to any one of Examples 164 to 167, wherein the tobacco material shreds have a width of at least about 0.5 millimeters.

[0595] [Example 169] An aerosol generating article according to any one of Examples 164 to 168, wherein the tobacco material shreds have a width of at least about 0.6 millimeters.

[0596] [Example 170] An aerosol generating article according to any one of Examples 164 to 169, wherein the tobacco material shreds have a width of about 2 millimeters or less.

[0597] [Example 171] An aerosol generating article according to any one of Examples 164 to 170, wherein the tobacco material shreds have a width of about 1.2 millimeters or less.

[0598] [Example 172] An aerosol generating article according to any one of Examples 164 to 171, wherein the tobacco material shreds have a width of about 0.9 millimeters or less.

[0599] [Example 173] An aerosol generating article according to any one of Examples 164 to 172, wherein the tobacco material shreds have a length of at least about 10 millimeters.

[0600] [Example 174] An aerosol generating article according to any one of Examples 164 to 173, wherein the tobacco material shreds have a length of about 40 millimeters or less.

[0601] [Example 175] An aerosol generating article according to any one of Examples 1 to 174, wherein the aerosol generating substrate comprises a plurality of pellets or granules of tobacco material.

[0602] [Example 176] The aerosol-generating article according to Example 175, wherein at least about 60 weight percent of the plurality of pellets or granules have a maximum dimension of more than about 1 millimeter.

[0603] [Example 177] The aerosol-generating article according to Example 175 or Example 176, wherein at least about 70 weight percent of the plurality of pellets or granules have a maximum dimension of more than about 1 millimeter.

[0604] [Example 178] The aerosol-generating article according to any one of Examples 175 to 177, wherein at least about 80 weight percent of the plurality of pellets or granules have a maximum dimension of more than about 1 millimeter.

[0605] [Example 179] The aerosol-generating article according to any one of Examples 175 to 178, wherein at least about 70 weight percent of the plurality of pellets or granules have a maximum dimension of more than about 0.5 millimeter.

[0606] [Example 180] The aerosol-generating article according to any one of Examples 175 to 179, wherein at least about 80 weight percent of the plurality of pellets or granules have a maximum dimension of more than about 0.5 millimeter.

[0607] [Example 181] The aerosol-generating article according to any one of Examples 175 to 180, wherein at least about 90 weight percent of the plurality of pellets or granules have a maximum dimension of more than about 0.5 millimeter.

[0608] [Example 182] The aerosol-generating article according to any one of Examples 1 to 181, wherein the aerosol-generating substrate comprises one or more sheets of tobacco material.

[0609] [Example 183] The aerosol generating article according to any one of Examples 1 to 182, further comprising a susceptor disposed inside the aerosol generating substrate.

[0610] [Example 184] The aerosol generating article according to any one of Examples 1 to 183, further comprising a mouthpiece element located downstream of the aerosol generating substrate.

[0611] [Example 185] The aerosol generating article according to any one of Examples 1 to 184, further comprising a mouth-side end cavity at the downstream end of the aerosol generating article.

[0612] [Example 186] The aerosol generating article according to Example 184 or 185, further comprising one or more intermediate elements between the aerosol generating substrate and the mouthpiece element.

[0613] [Example 187] The aerosol generating article according to Example 186, wherein at least one of the one or more intermediate elements is a hollow tubular element.

[0614] [Example 188] The aerosol generating article according to any one of Examples 1 to 187, wherein the weight of the upstream element is substantially the same as the combined weight of the tubular portion and the spiral sheet.

[0615] [Example 189] The aerosol generating article according to any one of Examples 1 to 188, wherein the density of the upstream element is smaller than the density of the aerosol generating substrate.

[0616] [Example 190] The aerosol generating article according to any one of Examples 1 to 189, wherein the RTD of the upstream element is smaller than the RTD of the aerosol generating substrate.

[0617] [Example 191] An aerosol generating system comprising an aerosol generating article according to any one of Examples 1 to 190 and an aerosol generating device configured to heat the aerosol generating substrate of the aerosol generating article, the aerosol generating device comprising a housing defining a cavity configured to receive the aerosol generating article.

[0618] [Example 192] The aerosol generating system according to Example 191, further comprising an external heating element.

[0619] Although only by way of illustration, the present invention will be further described with reference to the accompanying drawings.

[0620] FIG. 1 shows an aerosol generating article 10 having an upstream end 12 and a downstream end 14. The aerosol generating article 10 includes an aerosol generating substrate 16 and an upstream element 18 disposed upstream of the aerosol generating substrate 16. As shown in FIG. 1, the downstream end of the upstream element 18 is adjacent to the upstream end of the aerosol generating substrate 16. The aerosol generating article 10 further includes a hollow tubular element 20 located downstream of the aerosol generating substrate 16 and a mouthpiece element 22 downstream of the hollow tubular element 20. The upstream end 12 of the aerosol generating article 10 corresponds to the upstream end of the upstream element 18. The downstream end 14 of the aerosol generating article 10 corresponds to the downstream end of the mouthpiece element 22.

[0621] The aerosol generating article 10 has an overall length of about 45 millimeters and an outer diameter of about 7.1 millimeters.

[0622] The aerosol generating substrate 16 includes a plurality of strips of tobacco material surrounded by a plug wrap (not shown). The aerosol generating substrate 16 includes about 150 milligrams of tobacco material. The tobacco material includes about 13 weight percent to about 16 weight percent glycerin. About 80 percent of the strips of tobacco material have a width exceeding about 1 millimeter, and about 90 percent of the strips of tobacco material have a width exceeding about 0.5 millimeter. The density of the aerosol generating substrate 16 is about 300 milligrams per cubic centimeter.

[0623] The hollow tubular element 20 is a hollow cylindrical cardboard tube. The hollow cylindrical tube defines an internal cavity that extends from the upstream end of the hollow tubular element 20 to the downstream end of the hollow tubular element 20. Since the internal cavity of the hollow tubular element 20 is substantially empty, a substantially unrestricted air flow is possible along the internal cavity of the hollow tubular element 20. The hollow tubular element 20 does not substantially contribute to the overall RTD of the aerosol generating article 10.

[0624] The hollow tubular element 20 has a length of about 21 millimeters, an outer diameter of about 7.1 millimeters, and an inner diameter of about 6.7 millimeters. Therefore, the wall thickness of the hollow tubular element 20 is about 0.2 millimeters.

[0625] The aerosol generating article 10 comprises a ventilation zone at a position along the hollow tubular element. The ventilation zone includes a circumferential row of perforations 24 that extend through the tubular wall of the hollow tubular element 20 to allow air to flow from the outside of the aerosol generating article 10 into the internal cavity of the hollow tubular element 20.

[0626] The upstream end of the mouthpiece element 22 is adjacent to the downstream end of the hollow tubular element 20. The mouthpiece element 22 has a length of about 7 millimeters and an outer diameter of about 7.1 mm. The mouthpiece element 22 includes a segment of low-density cellulose acetate tow surrounded by a plug wrap (not shown).

[0627] As shown in FIG. 1, the aerosol generating article 10 comprises an upstream wrapper 26 surrounding the upstream element 18, an aerosol generating substrate 16, and a hollow tubular element 20. The ventilation zone comprises a circumferential row of perforations 28 that extend through the upstream wrapper 26. The circumferential row of perforations 28 that extend through the upstream wrapper 26 is above the circumferential row of perforations 24 that extend through the tubular wall of the hollow tubular element 20.

[0628] The aerosol-generating article 10 further comprises a downstream tipping wrapper 30 surrounding the hollow tubular element 20 and the mouthpiece element 22. The tipping wrapper 30 is located on top of a portion of the upstream wrapper 26 that is on top of the hollow tubular element 20. In this way, the tipping wrapper 30 effectively couples the mouthpiece element 22 to the other components of the aerosol-generating article 10. The ventilation zone may comprise a circumferential row of perforations (not shown) extending through the tipping wrapper 30. The circumferential row of perforations extending through the tipping wrapper 30 may be on top of the circumferential row of perforations 28 extending through the upstream wrapper 26 and the circumferential row of perforations 24 extending through the tubular wall of the hollow tubular element 20.

[0629] In FIG. 1, the upstream wrapper 26 and the downstream tipping wrapper 30 of the aerosol-generating article 10 are shown in a partially unenclosed state in order to show the upstream element 18, the aerosol-generating substrate 16, and the hollow tubular element 20 of the aerosol-generating article 10.

[0630] As shown in FIG. 2, the upstream element 18 of the aerosol-generating article 10 comprises a tubular portion 32 defining an inner region of the upstream element 18 and a spiral sheet 34 defining a plurality of longitudinally extending channels 36 within the inner region. The spiral sheet 34 and the plurality of longitudinally extending channels 36 extend along the entire length of the upstream element 18.

[0631] The tubular portion 32 is formed from a paper wrapper surrounding the spiral sheet 34. The paper wrapper forming the tubular portion 32 has a thickness of about 50 micrometers.

[0632] The spiral sheet 34 has a basis weight of about 30 grams per square meter and a surface area of about 850 square millimeters. The spiral sheet 34 is a spiral paper sheet. The paper sheet used to form the spiral sheet 34 is rectangular in shape and has a width of about 170 millimeters and a length of about 5 millimeters.

[0633] The spiral sheet 34 is an assembly of curled sheets. The spiral sheet 34 has a plurality of substantially parallel ridges 38 that extend substantially parallel to the major axis of the upstream element 18 (shown using dashed and dotted lines in Figure 2). Adjacent ridges 38 are separated by a distance of about 0.5 millimeters.

[0634] The upstream element 18 has a length of about 5 millimeters, an outer diameter D of about 7.1 millimeters, and an inner diameter of about 7 millimeters.

[0635] The upstream element 18 is substantially free of aerosol formers.

[0636] The specific embodiments and examples described above illustrate, but do not limit, the present invention. It will be understood that other embodiments of the present invention may be made and that the specific embodiments and examples described herein are not exhaustive.

Claims

1. An aerosol generating article comprising an aerosol generating substrate and an upstream element located upstream of the aerosol generating substrate, wherein the upstream element comprises a tubular portion defining an inner region of the upstream element, and a spiral sheet defining a plurality of channels extending in the major axis direction within the inner region, the spiral sheet having a basis weight of about 100 grams per square meter or less.

2. The aerosol generating article according to claim 1, wherein the spiral sheet has a weight of at least about 20 milligrams.

3. The aerosol generating article according to claim 1 or 2, wherein the spiral sheet has an average weight per unit volume of the inner region of at least about 100 micrograms per cubic millimeter.

4. The aerosol generating article according to any one of claims 1 to 3, wherein the sheet has a thickness of about 300 micrometers or less.

5. The aerosol generating article according to any one of claims 1 to 4, wherein the spiral sheet has a cross-sectional area of at least about 5 square millimeters.

6. The aerosol generating article according to any one of claims 1 to 5, wherein the spiral sheet has a surface area per unit length of at least about 50 square millimeters per millimeter.

7. The aerosol generating article according to any one of claims 1 to 6, wherein the spiral sheet has a length of about 2 millimeters to about 10 millimeters.

8. The aerosol generating article according to any one of claims 1 to 7, wherein the sheet has a width of at least about 50 millimeters.

9. The aerosol generating article according to any one of claims 1 to 8, wherein the spiral sheet is a spiral paper sheet.

10. The aerosol generating article according to any one of claims 1 to 9, wherein the sheet has a linear shrinkage rate of about 4 percent or less, and the linear shrinkage rate is measured according to test method A defined in the specification.

11. The aerosol generating article according to any one of claims 1 to 10, wherein the plurality of channels extending in the major axis direction have a maximum cross-sectional area of about 4 square millimeters or less.

12. The upstream element has a pull-out resistance of about 3 millimeters H or less per 1 millimeter of the length of the upstream element 2 The aerosol generating article according to any one of claims 1 to 11, having a pull-out resistance of 3 millimeters H or less per 1 millimeter of the length of the upstream element

13. The aerosol generating article according to any one of claims 1 to 12, wherein the aerosol generating substrate comprises a plurality of strips of tobacco material having a width of about 2 millimeters or less.

14. The aerosol generating article according to any one of claims 1 to 13, wherein the upstream element contains an aerosol former of about 1 weight percent or less based on the dry weight of the upstream element.

15. The aerosol generating article according to any one of claims 1 to 14, further comprising a susceptor disposed within the aerosol generating substrate.

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