Aerosol-generating article comprising combustion-preventing upstream element

Abstract

An aerosol-generating article (10) comprises: an aerosol-generating element comprising a strip (12) of aerosol-generating substrate defined by a strip package; an upstream element (48) located upstream of the aerosol-generating element, where the upstream element (48) comprises a section of material (50) defined by a first wrapper (52); and a second wrapper (54) defining both the upstream element (48) and the aerosol-generating element. The first wrapper (52) or the second wrapper (54), or both, contains a flame retardant composition at a location along the material segment (50) of the upstream element (48).

Description

Technical Field

[0001] The present invention relates to an aerosol-generating article comprising an aerosol-generating element and adapted to generate an inhalable aerosol upon heating. In particular, the present invention relates to an aerosol-generating article comprising an upstream element located upstream of the aerosol-generating element. Aspects of the present disclosure also relate to an aerosol-generating system comprising a heating device and an aerosol-generating article of the type described above. Background Art

[0002] Aerosol-generating articles in which an aerosol-generating element comprising an aerosol-generating substrate, such as a tobacco-containing substrate, is heated rather than combusted are known in the art. Typically, in such heated smoking articles, aerosol is generated by transferring heat from a heat source to a physically separate aerosol-generating substrate or material, which may be positioned in contact with, within, around, or downstream of the heat source. During use of the aerosol-generating article, volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source and are entrained in air drawn through the aerosol-generating article. When the released compounds cool, they condense to form an aerosol.

[0003] Several aerosol-generating devices for consuming aerosol-generating articles are known in the art. Such devices include, for example, electrically heated aerosol-generating devices, in which an aerosol is generated by transferring heat from one or more electrical heater elements of the aerosol-generating device to an aerosol-generating element of the aerosol-generating article. To this end, the aerosol-generating article is partially received within a heating chamber of the aerosol-generating device such that an upstream end of the aerosol-generating article is inserted into the chamber and a downstream end of the aerosol-generating article extends outside the chamber. For example, electrically heated aerosol-generating devices have been proposed that include internal heater blades adapted to be inserted into an aerosol-generating substrate when the aerosol-generating article is received within the heating chamber.

[0004] As an alternative, inductively heatable aerosol-generating articles have been proposed in WO 2015 / 176898. These aerosol-generating articles include an aerosol-generating element comprising an aerosol-generating substrate, such as a tobacco-containing substrate, and a susceptor disposed within the aerosol-generating substrate. When the aerosol-generating article is partially received within the heating chamber of an aerosol-generating device, functional coupling between the susceptor and the inductive heating element of the aerosol-generating device is achieved.

[0005] Aerosol-generating articles of the type discussed above typically comprise one or more additional elements, which are typically assembled together with the aerosol-generating element by means of one or more wrappers. The individual elements forming part of the aerosol-generating article may each have their own wrapper (a so-called "stick wrapper"). Two or more of the individual elements may be combined together by an "outer" wrapper. Examples of such additional elements include, but are not limited to, a mouthpiece segment arranged at the downstream end of the aerosol-generating article (which may, for example, be in the form of a rod of fibrous material such as cellulose acetate); a front element, i.e. an element arranged at the upstream end of the aerosol-generating article; and a cooling element suitable for assisting in cooling the aerosol generated when the aerosol-generating substrate is heated before the aerosol reaches the mouthpiece segment, etc. Where present, the mouthpiece segment is often attached to the rest of the aerosol-generating article by means of tipping paper to imitate the typical appearance of a conventional smoking article.

[0006] During use, aerosol-generating articles of the type discussed above will be exposed to heat provided by the heater element. Under these circumstances, conventional paper packaging can be susceptible to scorching or charring. To prevent this, and to desirably maintain a certain visual impact of the aerosol-generating article after its use, it has been proposed to combine a metal foil, such as aluminum foil, with a paper layer to provide a packaging that can be continuously exposed to high temperatures for an extended period of time. Furthermore, the use of a paper-metal foil laminate has been found to improve safety and prevent paper combustion or the delivery of paper pyrolysis products to the consumer during use of the aerosol-generating article. Summary of the Invention

[0007] There is a generally recognised need to provide a new and improved aerosol-generating article which is easier to dispose of and has less impact on the environment. Even more desirably, it would be beneficial to provide such an aerosol-generating article which is also adapted to prevent scorching or charring of the aerosol-generating article during use.

[0008] The present disclosure relates to an aerosol-generating article for generating an aerosol upon heating.

[0009] An aerosol-generating article may comprise an aerosol-generating element.

[0010] The aerosol-generating element may comprise a strip of aerosol-generating substrate.The aerosol-generating element may comprise a stick pack defining a strip of aerosol-generating substrate.

[0011] The aerosol-generating article may comprise an upstream element located upstream of the aerosol-generating element.

[0012] The upstream element may comprise a material segment. The upstream element may comprise a first wrapper defining the material segment. The first wrapper may comprise a flame retardant composition at a location along the material segment of the upstream element.

[0013] The aerosol-generating article may comprise a second wrapper defining both the upstream element and the aerosol-generating element.The second wrapper may comprise the flame retardant composition at a position along the material section of the upstream element.

[0014] According to a first aspect of the present invention, there is provided an aerosol-generating article for generating an aerosol upon heating. The aerosol-generating article comprises an aerosol-generating element comprising a strip of aerosol-generating substrate defined by a stick package. The aerosol-generating article further comprises an upstream element positioned upstream of the aerosol-generating element, wherein the upstream element comprises a material segment defined by the first package. Additionally, the aerosol-generating article comprises a second package defining both the upstream element and the aerosol-generating element. The first package or the second package or both comprise a flame retardant composition at a position along the material segment of the upstream element, the flame retardant composition comprising one or more flame retardant compounds.

[0015] As used herein with reference to the present invention, the term "aerosol-generating article" is used to describe an article comprising an aerosol-generating substrate, which article is heated to generate an inhalable aerosol for delivery to a user.

[0016] As used herein with reference to the present invention, the term "aerosol-generating substrate" is used to describe a substrate comprising an aerosol-generating material, which substrate is capable of releasing volatile compounds that can generate an aerosol upon heating.

[0017] As used herein with reference to the present invention, the term "aerosol" is used to describe a dispersion of solid particles or liquid droplets, or a combination of solid particles and liquid droplets, in a gas. Aerosols can be visible or invisible. Aerosols can include vapors of substances that are normally liquid or solid at room temperature, as well as solid particles or liquid droplets, or a combination of solid particles and liquid droplets.

[0018] As used herein with reference to the present invention, the term "aerosol-generating device" is used to describe a device that interacts with the aerosol-generating substrate of an aerosol-generating article to generate an aerosol.

[0019] Aerosol-generating articles according to the present invention have a proximal end through which, in use, an aerosol exits the aerosol-generating article for delivery to a user. The proximal end of the aerosol-generating article may also be referred to as the downstream end or mouth end of the aerosol-generating article. In use, the user draws directly or indirectly on the proximal end of the aerosol-generating article to inhale the aerosol generated by the aerosol-generating article.

[0020] The aerosol-generating article according to the present invention has a distal end. The distal end is opposite 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.

[0021] Components of aerosol-generating articles according to the invention may be described as being upstream or downstream of each other based on their relative position between the proximal end of the aerosol-generating article and the distal end of the aerosol-generating article.

[0022] As used herein with reference to the present invention, the term "longitudinal" is used to describe the direction between the upstream and downstream ends of the aerosol-generating article.During use, air is drawn through the aerosol-generating article in the longitudinal direction.

[0023] As used herein with reference to the present invention, the term "length" is used to describe the largest dimension of an aerosol-generating article or a component of an aerosol-generating article in the longitudinal direction.

[0024] As used herein with reference to the present invention, the term "transverse" is used to describe a direction perpendicular to the longitudinal direction. Unless otherwise stated, references to a "section" of an aerosol-generating article or component of an aerosol-generating article refer to a cross-section.

[0025] As used herein with reference to the present invention, the term "width" refers to the largest dimension of an aerosol-generating article or a component of an aerosol-generating article in the transverse direction. Where 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. Where the 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.

[0026] As used herein with reference to the present invention, the term "hollow tubular element" is used to refer to a generally cylindrical element having a lumen along its longitudinal axis. The tubular portion may have a generally circular, oval, or elliptical cross-section. The lumen may have a generally circular, oval, or elliptical cross-section. In particular, the term "hollow tubular element" is used to refer to an element that defines at least one airflow conduit that establishes uninterrupted fluid communication between an upstream end of the hollow tubular element and a downstream end of the tubular element.

[0027] Unless otherwise stated, the resistance to draw (RTD) of components or aerosol-generating articles according to the present invention is measured in accordance with ISO 6565-2015. RTD refers to the pressure required to force air through the full length of the component. The terms "pressure drop" or "draw resistance" of a component or article may also refer to "resistance to draw". Such terms generally refer to measurements in accordance with ISO 6565-2015 and are typically made at a temperature of about 22 degrees Celsius, a pressure of about 101 kPa (about 760 Torr) and a relative humidity of about 60% at a volumetric flow rate of about 17.5 ml / s at the output or downstream end of the measurement component.

[0028] The expression "resistance to draw (RTD) per unit length" of a particular component (or element) of an aerosol-generating article (such as an upstream element, an aerosol-generating element, etc.) can be calculated by dividing the measured resistance to draw of the component by the total axial length of the component. The RTD per unit length refers to the pressure required to force air through a unit length of the component. Throughout this disclosure, a unit length refers to a length of 1 mm. Therefore, in order to derive the RTD per unit length of a particular component, a sample of the component of a particular length (e.g., 15 mm) can be used for measurement. The RTD of such a sample is measured according to ISO 6565-2015. For example, if the measured RTD is approximately 15 mm H2O, the RTD per unit length of the component is approximately 1 mm H2O / mm. The RTD per unit length of a component generally depends on the structural properties of the material used for the component and the cross-sectional geometry or profile of the component, among other factors.

[0029] As briefly described above, an aerosol-generating article according to one aspect of the present invention comprises an aerosol-generating element and an upstream element located upstream of the aerosol-generating element, wherein the upstream element comprises a material segment defined by a first wrapper. In the aerosol-generating article, a second wrapper defines both the upstream element and the aerosol-generating element, for example to combine them together. Compared to existing aerosol-generating articles, one or both of the first wrapper and the second wrapper comprises a flame retardant composition comprising one or more flame retardant compounds at a location along the material segment of the upstream element.

[0030] Confining the upstream element with a wrapper containing a flame retardant composition at a location along the material segment of the upstream element is beneficial because it helps prevent combustion of the upstream element. Thus, if a user attempts to ignite an aerosol-generating article according to the present invention at its distal end—as they would a conventional cigarette—the burning front will be arrested before it can advance all the way to the aerosol-generating element. Thus, the inappropriate use of aerosol-generating articles intended to be heated in a dedicated device to generate an inhalable aerosol is desirably prevented.

[0031] In addition, by defining the upstream element with a wrapper containing a flame retardant composition at a position along the material segment of the upstream element, it is advantageously possible to prevent one or more wrappers and the underlying material segment from charring or burning due to heating during the intended use of the aerosol-generating article in combination with the heating device. This desired effect can be achieved without the need for additional layers of metal foil or other heat shielding material in the article. In particular, the inventors have found that by using one or more wrappers according to the present invention, the occurrence of charring or burning of the wrapper(s) or the underlying material segment can be substantially avoided when the upstream element is exposed to temperatures in the range of 150 to 370 degrees Celsius. This is advantageous in aerosol-generating devices in which heat is supplied by means of a resistive heater element inserted into the aerosol-generating substrate, for example, to a temperature of approximately 350 degrees Celsius, and in aerosol-generating devices in which heat is supplied inductively by means of a sensor element embedded in the aerosol-generating substrate, for example, to a temperature of approximately 260 degrees Celsius.

[0032] Aerosol-generating articles according to the present invention are easy to dispose of after use and have reduced environmental impact, as there is no need to include a metal foil layer as a heat shield, as is common in existing aerosol-generating articles.

[0033] The advantageous effects described above are particularly welcome in embodiments of aerosol-generating articles in which the upstream element is formed entirely or predominantly of a flammable material such as curled paper and / or cardboard, which are more environmentally friendly and cost-effective alternatives to other known materials. The use of a flame retardant composition according to the present invention in place of metal foil will increase the already high level of environmental friendliness of the article as a whole.

[0034] By adjusting the amount of flame retardant composition in or on one or more packages - for example, in terms of the amount per square meter of surface area of ​​the package base material, the extent to which the surface of the one or more packages is treated with the flame retardant composition, and the formulation of the flame retardant composition itself - the flame retardant properties of the distal portion of the aerosol-generating article and to some extent the aerosol-generating article as a whole can be advantageously enhanced.

[0035] Aerosol-generating articles according to the present invention can be manufactured efficiently and at high speed without requiring major modifications to existing equipment.

[0036] In some embodiments, the first wrapper comprises a packaging base material, and the flame retardant composition is disposed on a surface of the packaging base material material segment facing the upstream element, a surface of the packaging base material material segment facing away from the upstream element, or both.

[0037] Preferably, the second wrapper comprises a packaging base material, and the flame retardant composition is provided on a surface of the material segment of the packaging base material facing the upstream element, a surface of the material segment of the packaging base material facing away from the upstream element, or both.

[0038] Thus, many different possible arrangements are possible. Placing the flame retardant composition closer to or further away from the material segment of the upstream component may have some impact, as some of the flame retardant composition may be more or less likely to migrate into the material segment. In the context of the present invention, some degree of migration of the flame retardant composition into the material segment may be advantageous, as it may further help prevent combustion of the material segment in the event of misuse of the aerosol-generating article.

[0039] As briefly described above, in an aerosol-generating article according to the present invention, one or more wrappers defining an upstream element comprise a flame retardant composition comprising one or more flame retardant compounds at a position along the material segment of the upstream element. In practice, at least one wrapper comprises a packaging base material and the flame retardant composition comprising one or more flame retardant compounds may be applied as a coating to the packaging base material or the packaging base material may be impregnated with the flame retardant composition or both. As a further alternative, the flame retardant composition comprising one or more flame retardant compounds may be included in one or more wrappers during the manufacture of the packaging material itself. For example, during the manufacture of paper-based or polymer-based packaging material, the flame retardant composition may be added to the paper pulp or polymer mixture during the wrapper manufacturing process. This may be advantageous because the manufacturing process is shortened and a more uniform distribution of the flame retardant compound throughout the packaging material may be obtained.

[0040] The term "flame retardant compound" is used herein to describe chemical compounds that, when applied to or otherwise incorporated into a substrate such as paper or a plastic compound, provide varying degrees of protection from flammability. In practice, flame retardant compounds can be activated by the presence of an ignition source and are adapted to prevent or slow the further development of an ignition through a variety of different physical and chemical mechanisms.

[0041] The flame retardant composition may also typically include one or more non-flame retardant compounds, i.e., one or more compounds - such as solvents, excipients, fillers - which do not actively contribute to providing flammability protection to the substrate, but are used to facilitate the application of one or more flame retardant compounds to or in the packaging, or both.

[0042] Some non-flame retardant compounds of the flame retardant composition, such as solvents, are volatile and may evaporate from the packaging upon drying after the flame retardant composition has been applied to or into the packaging base material, or both. Thus, although such non-flame retardant compounds form part of the formulation of the flame retardant composition, they may no longer be present or may only be detectable in trace amounts in one or more packages of the aerosol-generating article according to the present invention.

[0043] In order to provide the flame retardant composition in paper-based or polymer-based packaging, the flame retardant composition can be added to the paper pulp or polymer mixture during the packaging manufacturing process or added to the packaging base material at a later stage by an application process based on size pressing, spraying, printing, coating, etc. The flame retardant composition can be applied, for example, as a layer to one side of the packaging base material or to both sides of the packaging base material.

[0044] Many suitable flame retardant compounds are known. Some flame retardant compounds, such as mineral flame retardants, act primarily as additive flame retardants and do not chemically attach to surrounding systems. Most organohalogen and organophosphate compounds also do not permanently react and attach themselves to their surroundings. Reactive flame retardant compounds, such as certain non-halogenated products, are reactive in that they will integrate into surrounding systems without losing their flame retardant effectiveness. This makes these materials advantageously non-invasive to the environment.

[0045] The packaging base material of the one or more wrappers defining the material segments of the upstream element may be a paper packaging base material or a non-paper packaging base material. In a preferred embodiment, the packaging base material of the wrappers defining the material segments of the upstream element comprises paper. Suitable paper packaging base materials for use in specific embodiments of the present invention are known in the art and include, but are not limited to: cigarette paper; and filter segment packaging. Suitable non-paper packaging base materials for use in specific embodiments of the present invention are known in the art and include, but are not limited to, sheets of homogenized tobacco material and sheets of certain polymeric materials. In certain embodiments, the packaging base material may be formed from a laminate comprising a plurality of layers.

[0046] In some embodiments, the packaging base material of the one or more packages defining the material segment of the upstream element may be non-porous. In particular, the packaging base material of the first package may be non-porous.

[0047] In some embodiments, the packaging base material of the first package can have an air permeability of less than about 20 Coresta units.

[0048] "Coresta Unit" is a unit of air permeability of a sheet material, which corresponds to the air flow (cubic centimeters per minute) through a surface area of ​​1 square centimeter of the test material at a measuring pressure of 1.00 kPa. The measuring pressure is the pressure difference between the two faces of the test material during the measurement. Thus, the unit corresponding to the Coresta Unit is cubic centimeters per minute per square centimeter (cm3) at 1.00 kPa. 3 min -1 cm -2 A suitable method for determining the air permeability of sheet materials for use in the present invention is described in ISO Standard 2965:2009.

[0049] The air permeability of the test piece is calculated in Coresta units (CU) using the following formula:

[0050] CU=[Q / A]×[1 / d]

[0051] Where Q is the measured air flow through the test piece in cubic centimeters per minute, A is the surface area of ​​the test piece in square centimeters, and d is the actual measurement of the pressure difference across the two surfaces of the test piece in kilopascals.

[0052] A wrapper having an air permeability of less than 20 Coresta units may also be described herein as "substantially impermeable." In preferred embodiments, the first wrapper has an air permeability of less than 20 Coresta units, more preferably less than 10 Coresta units, and even more preferably less than 5 Coresta units. In some particularly preferred embodiments, the air permeability of a substantially impermeable wrapper may have a lower limit of 1 Coresta unit.

[0053] For example, the packaging base material can have a basis weight of at least about 20 grams per square meter. Preferably, the packaging base material has a basis weight of at least about 25 grams per square meter. More preferably, the packaging base material has a basis weight of at least about 30 grams per square meter. Even more preferably, the packaging base material has a basis weight of at least about 40 grams per square meter.

[0054] The packaging base material may have a basis weight of up to about 120 g / m². Preferably, the packaging base material has a basis weight of less than or equal to about 110 g / m². More preferably, the packaging base material has a basis weight of less than or equal to about 100 g / m². Even more preferably, the packaging base material has a basis weight of less than or equal to about 90 g / m².

[0055] In some embodiments, the packaging base material may have a basis weight of about 20 g / m² to about 120 g / m², preferably about 25 g / m² to about 120 g / m², more preferably about 30 g / m² to about 120 g / m², and even more preferably about 40 g / m² to about 120 g / m². In other embodiments, the packaging base material may have a basis weight of about 20 g / m² to about 110 g / m², preferably about 25 g / m² to about 110 g / m², more preferably about 30 g / m² to about 110 g / m², and even more preferably about 40 g / m² to about 110 g / m². In yet other embodiments, the packaging base material may have a basis weight of about 20 g / m² to about 100 g / m², preferably about 25 g / m² to about 100 g / m², more preferably about 30 g / m² to about 100 g / m², and even more preferably about 40 g / m² to about 100 g / m². In yet other embodiments, the packaging base material may have a basis weight of about 20 g / m2 to about 90 g / m2, preferably about 25 g / m2 to about 90 g / m2, more preferably about 30 g / m2 to about 90 g / m2, and even more preferably about 40 g / m2 to about 90 g / m2.

[0056] For example, the first wrapper defining the material segment of the upstream element may comprise a packaging base material having a basis weight of up to 100 g / m 2 .

[0057] For example, a second packaging defining both the upstream element and the aerosol-generating element, i.e., a packaging combining the upstream element and the aerosol-generating element together, may comprise a packaging base material having a basis weight of 20 to 60 g / m2, preferably 25 to 50 g / m2.

[0058] The packaging base material may have a thickness of at least 20 microns. Preferably, the packaging base material has a thickness of at least 25 microns. More preferably, the packaging base material has a thickness of at least 30 microns.

[0059] The packaging base material may have a thickness of less than or equal to 130 microns. Preferably, the packaging base material has a thickness of less than or equal to 120 microns. More preferably, the packaging base material has a thickness of less than or equal to 110 microns. Even more preferably, the packaging base material has a thickness of less than or equal to 100 microns or less than or equal to 90 microns.

[0060] In some embodiments, the packaging base material has a thickness of 20 to 130 microns, preferably 20 to 120 microns, more preferably 20 to 110 microns, even more preferably 20 to 100 microns, or 20 to 90 microns. In other embodiments, the packaging base material has a thickness of 25 to 130 microns, preferably 25 to 120 microns, more preferably 25 to 110 microns, even more preferably 25 to 100 microns, or 25 to 90 microns. In further embodiments, the packaging base material has a thickness of 30 to 130 microns, preferably 30 to 120 microns, more preferably 30 to 110 microns, even more preferably 30 to 100 microns, or 30 to 90 microns.

[0061] For example, the first wrapper defining the material segment of the upstream element may comprise a wrapper base material having a thickness of up to 125 microns.

[0062] For example, the second wrapper defining both the upstream element and the aerosol-generating element, ie the wrapper combining the upstream element and the aerosol-generating element together, may have a thickness of 40 to 75 microns.

[0063] The wrapper, which at least defines the strip of aerosol-generating substrate, has an overall dry basis weight that is the sum of the basis weight of the packaging base material and the weight of the flame retardant composition components present on or within the packaging base material, or both. The weight of the flame retardant composition components present on or in the wrapper is the sum of the total weight of the one or more flame retardant compounds and the weight of any residual non-flame retardant compounds. Within the context of the present invention, the weight of the flame retardant composition components is also expressed in grams of the components per square meter of packaging base material.

[0064] The ratio of the total weight of the flame retardant compound(s) to the overall dry basis weight of the package can be taken as an indication of the concentration of the flame retardant compound(s) in the package.

[0065] In aerosol-generating articles according to the present invention, the ratio of the total weight of the flame retardant compound(s) to the total dry weight of the packaging may be at least about 0.02. Preferably, the ratio of the total weight of the flame retardant compound(s) to the total dry weight of the packaging is at least about 0.03. More preferably, the ratio of the total weight of the flame retardant compound(s) to the total dry weight of the packaging is at least about 0.04. Even more preferably, the ratio of the total weight of the flame retardant compound(s) to the total dry weight of the packaging is at least about 0.05.

[0066] Preferably, the ratio of the total weight of the flame retardant compound(s) to the total dry weight of the package is less than or equal to about 0.20. More preferably, the ratio of the total weight of the flame retardant compound(s) to the total dry weight of the package is less than or equal to about 0.15. Even more preferably, the ratio of the total weight of the flame retardant compound(s) to the total dry weight of the package is less than or equal to about 0.10.

[0067] In some embodiments, the ratio of the total weight of the (one or more) flame retardant compounds to the overall dry weight of the package may be from about 0.02 to about 0.20, preferably from about 0.03 to about 0.20, more preferably from about 0.04 to about 0.20, and even more preferably from about 0.05 to about 0.20. In other embodiments, the ratio of the total weight of the (one or more) flame retardant compounds to the overall dry weight of the package may be from about 0.02 to about 0.15, preferably from about 0.03 to about 0.15, more preferably from about 0.04 to about 0.15, and even more preferably from about 0.05 to about 0.15. In further embodiments, the ratio of the total weight of the (one or more) flame retardant compounds to the overall dry weight of the package may be from about 0.02 to about 0.10, preferably from about 0.03 to about 0.10, more preferably from about 0.04 to about 0.10, and even more preferably from about 0.05 to about 0.10.

[0068] In the aerosol-generating article according to the present invention, the flame retardant composition is provided in the treated portion of the packaging. This means that the flame retardant composition has been applied to or into the corresponding portion of the packaging base material, or has been applied to both the corresponding portion and the corresponding portion of the packaging base material. Thus, in the treated portion, the packaging has an overall dry basis weight that is greater than the dry basis weight of the packaging base material.

[0069] The treated portion of the wrapper can extend over at least about 10% of the outer surface area of ​​the material segments of the upstream element defined by the wrapper. Preferably, the treated portion of the wrapper extends over at least about 20% of the outer surface area of ​​the material segments of the upstream element defined by the wrapper. More preferably, the treated portion of the wrapper extends over at least about 40% of the outer surface area of ​​the material segments of the upstream element. Even more preferably, the treated portion of the wrapper extends over at least about 60% of the outer surface area of ​​the material segments of the upstream element. Most preferably, the treated portion of the wrapper extends over at least about 80% of the outer surface area of ​​the material segments of the upstream element.

[0070] In a particularly preferred embodiment, the treated portion of the wrapper extends over at least about 90% of the outer surface area of ​​the material segment of the upstream element. Even more preferably, the treated portion of the wrapper extends over at least about 95% of the outer surface area of ​​the material segment of the upstream element. Most preferably, the treated portion of the wrapper extends over substantially the entire outer surface area of ​​the material segment of the upstream element.

[0071] The length of the treated region may be at least about 10% of the length of the material segment of the upstream element. Preferably, the length of the treated region is at least about 20% of the length of the material segment of the upstream element. More preferably, the length of the treated region is at least about 40% of the length of the material segment of the upstream element. Even more preferably, the length of the treated region is at least about 60% of the length of the material segment of the upstream element. Most preferably, the length of the treated region is at least about 80% of the length of the material segment of the upstream element.

[0072] In a particularly preferred embodiment, the length of the treated area is at least about 90% of the length of the material segment of the upstream element. Even more preferably, the length of the treated area is at least about 95% of the length of the material segment of the upstream element. Most preferably, the length of the treated area is substantially equal to the length of the material segment of the upstream element.

[0073] At least about 10 grams of the flame retardant composition may be applied to the treated portion per square meter of treated portion surface area. Preferably, at least about 12 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area. More preferably, at least about 14 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area. Even more preferably, at least about 16 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area. In particularly preferred embodiments, at least about 18 grams or at least about 20 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area.

[0074] Preferably, less than or equal to about 35 grams of the flame retardant composition is applied to the treated portion per square meter of the treated portion surface area. More preferably, less than or equal to about 30 grams of the flame retardant composition is applied to the treated portion per square meter of the treated portion surface area. Even more preferably, less than or equal to about 25 grams of the flame retardant composition is applied to the treated portion per square meter of the treated portion surface area.

[0075] In some embodiments, about 10 grams to about 35 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area. Preferably, about 12 grams to about 35 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area. More preferably, about 14 grams to about 35 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area. Even more preferably, about 16 grams to about 35 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area. In particularly preferred embodiments, about 18 grams to about 35 grams or about 20 grams to about 35 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area.

[0076] In other embodiments, about 10 grams to about 30 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area. Preferably, about 12 grams to about 30 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area. More preferably, about 14 grams to about 30 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area. Even more preferably, about 16 grams to about 30 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area. In particularly preferred embodiments, about 18 grams to about 30 grams or about 20 grams to about 30 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area.

[0077] In further embodiments, about 10 grams to about 25 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area. Preferably, about 12 grams to about 25 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area. More preferably, about 14 grams to about 25 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area. Even more preferably, about 16 grams to about 25 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area. In particularly preferred embodiments, about 18 grams to about 25 grams or about 20 grams to about 25 grams of the flame retardant composition is applied to the treated portion per square meter of treated portion surface area.

[0078] The treated portion of the wrapper may contain at least about 0.1 grams of one or more flame retardant compounds per square meter of treated portion surface area. Preferably, the treated portion of the wrapper contains at least about 0.5 grams of one or more flame retardant compounds per square meter of treated portion surface area. More preferably, the treated portion of the wrapper contains at least about 1.0 grams of one or more flame retardant compounds per square meter of treated portion surface area. Even more preferably, the treated portion of the wrapper contains at least about 2.0 grams of one or more flame retardant compounds per square meter of treated portion surface area. In particularly preferred embodiments, the treated portion of the wrapper contains at least about 3.0 grams of one or more flame retardant compounds per square meter of treated portion surface area, or at least about 4.0 grams of one or more flame retardant compounds per square meter of treated portion surface area, or at least about 5.0 grams of one or more flame retardant compounds per square meter of treated portion surface area.

[0079] In some embodiments, the treated portion of the wrapper comprises at least about 10 grams of one or more flame retardant compounds per square meter of surface area of ​​the treated portion.

[0080] Preferably, the treated portion of the wrapper comprises less than or equal to about 100 grams of the one or more flame retardant compounds per square meter of the treated portion surface area. More preferably, the treated portion of the wrapper comprises less than or equal to about 50 grams of the one or more flame retardant compounds per square meter of the treated portion surface area. Even more preferably, the treated portion of the wrapper comprises less than or equal to about 25 grams of the one or more flame retardant compounds per square meter of the treated portion surface area.

[0081] In some embodiments, the treated portion of the package comprises from about 0.5 grams to about 12 grams of one or more flame retardant compounds per square meter of treated portion surface area, preferably from about 1.0 grams to about 12 grams of one or more flame retardant compounds per square meter of treated portion surface area, more preferably from about 2.0 grams to about 12 grams of one or more flame retardant compounds per square meter of treated portion surface area, and even more preferably from about 3.0 grams to about 12 grams of one or more flame retardant compounds per square meter of treated portion surface area.

[0082] In other embodiments, the treated portion of the package comprises from about 0.5 grams to about 10 grams of one or more flame retardant compounds per square meter of treated portion surface area, preferably from about 1.0 grams to about 10 grams of one or more flame retardant compounds per square meter of treated portion surface area, more preferably from about 2.0 grams to about 10 grams of one or more flame retardant compounds per square meter of treated portion surface area, and even more preferably from about 3.0 grams to about 120 grams of one or more flame retardant compounds per square meter of treated portion surface area.

[0083] In further embodiments, the treated portion of the package comprises from about 0.5 grams to about 8 grams of one or more flame retardant compounds per square meter of treated portion surface area, preferably from about 1.0 grams to about 12 grams of one or more flame retardant compounds per square meter of treated portion surface area, more preferably from about 2.0 grams to about 8 grams of one or more flame retardant compounds per square meter of treated portion surface area, and even more preferably from about 3.0 grams to about 8 grams of one or more flame retardant compounds per square meter of treated portion surface area.

[0084] In some particularly preferred embodiments, the treated portion of the packaging material contains about 10 grams to about 100 grams of one or more flame retardant compounds per square meter of treated portion surface area, preferably about 10 grams to about 50 grams of one or more flame retardant compounds per square meter of treated portion surface area, and more preferably about 10 grams to about 25 grams of one or more flame retardant compounds per square meter of treated portion surface area.

[0085] In an aerosol-generating article according to the present invention, the amount of the one or more flame retardant compounds in the treated portion is preferably such that the aerosol-generating article does not ignite when heated using a resistance heating coil at 500 degrees Celsius for at least 5 seconds, preferably 30 seconds. The term "does not ignite" is used herein to specifically refer to that combustion of the packaging defining the aerosol-generating substrate is not initiated and no flame is detected.

[0086] Preferably, an aerosol-generating article according to the present invention does not ignite when subjected to Health Canada's Intense regime, which includes a pre-ignition step using a resistive heating coil and a puff pattern of 55 ml at a time for 2 seconds every 30 seconds with 100% of the ventilation area on the aerosol-generating article (if present) blocked. Further details on "smoking" parameters and standard test conditions are provided in ISO 3308:2000 (Conventional analytical smoking machines - Definitions and standard conditions).

[0087] Many suitable flame retardant compounds will be known to the skilled person.In particular, several flame retardant compounds and formulations suitable for treating cellulosic materials are known and have been disclosed and can be used in the manufacture of packaging for aerosol-generating articles according to the present invention.

[0088] In some embodiments, the flame retardant composition comprises a polymer and a mixed salt based on at least one monocarboxylic acid, dicarboxylic acid, and / or tricarboxylic acid, at least one polyphosphoric acid, pyrophosphoric acid, and / or phosphoric acid, and a hydroxide or salt of an alkali metal or alkaline earth metal, wherein the at least one monocarboxylic acid, dicarboxylic acid, and / or tricarboxylic acid forms a carboxylate with the hydroxide or salt, and the at least one polyphosphoric acid, pyrophosphoric acid, and / or phosphoric acid forms a phosphate with the hydroxide or salt.

[0089] Preferably, in such embodiments, the flame retardant composition further comprises a carbonate of an alkali metal or an alkaline earth metal.

[0090] In other embodiments, the flame retardant composition comprises at least one C 10 or higher fatty acids, tall oil fatty acids (TOFA), phosphorylated linseed oil, phosphorylated downstream corn oil modified cellulose. Preferably, the at least one C 10 The fatty acid or higher fatty acid is selected from the group consisting of capric acid, myristic acid, palmitic acid and combinations thereof.

[0091] Preferably, in an aerosol-generating article according to the present invention, neither the first package nor the second package comprises metal. This may advantageously enhance the environmental friendliness of the aerosol-generating article according to the present invention, as one or more metal components do not need to be separated from the rest of the article upon disposal.

[0092] In some embodiments, the upstream element is arranged immediately upstream of the aerosol-generating element. Preferably, the upstream element abuts the upstream end of the aerosol-generating article. Thus, the upstream element may extend from the upstream end of the aerosol-generating element to the upstream end or distal end of the aerosol-generating article.

[0093] In other embodiments, the aerosol-generating article comprises one or more intermediate components disposed between the upstream element and the aerosol-generating element. Preferably, the upstream element abuts the upstream end of one such intermediate component disposed immediately downstream of the upstream element. Thus, the upstream element may extend from the upstream end of the intermediate component to the upstream or distal end of the aerosol-generating article.

[0094] The aerosol-generating article may comprise an air inlet at an upstream end of the aerosol-generating article, and the air inlet may be provided by the upstream element.Air entering through the air inlet may enter the aerosol-generating element to generate the mainstream aerosol.

[0095] The upstream element can advantageously prevent direct physical contact with the upstream end of the aerosol-generating element. In particular, in embodiments in which the aerosol-generating element comprises a susceptor element embedded within an aerosol-generating substrate, as will be discussed in greater detail below, the upstream element can prevent direct physical contact with the upstream end of the susceptor element. This helps prevent the susceptor element from shifting or deforming during handling or transport of the aerosol-generating article. This, in turn, helps secure the form and position of the susceptor element. Furthermore, the presence of the upstream element can help prevent any loss of the aerosol-generating substrate, which can be advantageous, for example, if the aerosol-generating substrate contains a particulate material, such as particulate plant material.

[0096] The upstream element may also provide an improved appearance for the upstream end of the aerosol-generating article. In addition, if desired, the upstream element may be used to provide information about the aerosol-generating article, such as information about the brand, flavor, contents or details of the aerosol-generating device with which the article is intended to be used.

[0097] The material segment of the upstream element may be in the form of a porous rod element. The porous rod element may have a porosity of at least about 50% in the longitudinal direction of the aerosol-generating article. More preferably, the porous rod element has a porosity of between about 50% and about 90% in the longitudinal direction. The porosity of the porous rod element in the longitudinal direction is defined by the ratio of the cross-sectional area of ​​the material forming the porous rod element to the internal cross-sectional area of ​​the aerosol-generating article at the location of the porous rod element.

[0098] The porous rod element may be made of a porous material or may include a plurality of openings. For example, this may be achieved by laser perforation. Preferably, the plurality of openings are uniformly distributed across the cross section of the porous rod element.

[0099] The porosity or permeability of the upstream element may advantageously be varied in order to provide a desired overall resistance to draw of the aerosol-generating article.

[0100] In alternative embodiments, the upstream element may be formed from a material that is impermeable to air.In such embodiments, the aerosol-generating article may be configured so that air flows into the aerosol-generating element via suitable ventilation means provided in the packaging.

[0101] The material segment of the upstream element can comprise any material suitable for use in an aerosol-generating article. For example, the material segment of the upstream element can comprise a filter material, a ceramic, a polymeric material, cellulose acetate, paper, cardboard, a zeolite, or an aerosol-generating matrix. Preferably, the material segment comprises a rod of cellulose acetate. In some embodiments, the material segment of the upstream element is substantially made of paper.

[0102] Preferably, the diameter of the upstream element is substantially equal to the diameter of the aerosol-generating article.

[0103] Preferably, the upstream element has an outer diameter of at least about 5 mm. More preferably, the upstream element has an outer diameter of at least about 6 mm. Even more preferably, the upstream element has an outer diameter of at least about 7 mm.

[0104] The upstream element preferably has an outer diameter of less than or equal to about 12 mm. More preferably, the upstream element has an outer diameter of less than or equal to about 10 mm. Even more preferably, the upstream element has an outer diameter of less than or equal to about 8 mm.

[0105] In some embodiments, the upstream element has an outer diameter of about 5 mm to about 12 mm, preferably about 5 mm to about 10 mm, and more preferably about 5 mm to about 8 mm. In other embodiments, the upstream element has an outer diameter of about 6 mm to about 12 mm, preferably about 6 mm to about 10 mm, and more preferably about 6 mm to about 8 mm. In still other embodiments, the upstream element has an outer diameter of about 7 mm to about 12 mm, preferably about 7 mm to about 10 mm, and more preferably about 7 mm to about 8 mm.

[0106] The upstream element may have a length of at least about 1 mm. For example, the upstream element may have a length of at least about 2 mm, preferably at least about 4 mm, more preferably at least about 6 mm.

[0107] The upstream element may have a length of less than or equal to about 25 mm. For example, the upstream element may have a length of less than or equal to about 20 mm, preferably less than or equal to about 15 mm, more preferably less than or equal to about 12 mm, and even more preferably less than or equal to about 10 mm. In a particularly preferred embodiment, the upstream element has a length of less than or equal to about 10 mm.

[0108] In some embodiments, the upstream element has a length of about 1 mm to about 20 mm, preferably about 1 mm to about 15 mm, more preferably about 1 mm to about 12 mm, even more preferably about 1 mm to about 10 mm, and most preferably about 1 mm to about 8 mm.

[0109] In other embodiments, the upstream element has a length of about 2 mm to about 20 mm, preferably about 2 mm to about 15 mm, more preferably about 2 mm to about 12 mm, even more preferably about 2 mm to about 10 mm, and most preferably about 2 mm to about 8 mm.

[0110] In further embodiments, the upstream element has a length of about 4 mm to about 20 mm, preferably about 4 mm to about 15 mm, more preferably about 4 mm to about 12 mm, even more preferably about 4 mm to about 10 mm, and most preferably about 4 mm to about 8 mm.

[0111] In yet other embodiments, the upstream element has a length of about 6 mm to about 20 mm, preferably about 6 mm to about 15 mm, more preferably about 6 mm to about 12 mm, even more preferably about 6 mm to about 10 mm, and most preferably about 6 mm to about 8 mm.

[0112] The length of the upstream element can advantageously be varied to adjust the overall length of the aerosol-generating article. For example, where it is desired to reduce the length of one of the other components of the aerosol-generating article, the length of the upstream element can be increased in order to maintain the same overall length of the article. Furthermore, by adjusting the length of the upstream element, it may be possible to control how much the aerosol-generating article protrudes from the heating chamber of the aerosol-generating device when the aerosol-generating article is inserted into the heating chamber during use.

[0113] The material segment of the upstream element preferably has a substantially uniform structure. For example, the material segment of the upstream element may be substantially uniform in texture and appearance. The material segment of the upstream element may, for example, have a continuous regular surface across its entire cross-section. The material segment of the upstream element may, for example, lack discernible symmetry.

[0114] The material segment of the upstream element may be in the form of a tubular body. Thus, the material segment of the upstream element may internally define a cavity extending from the upstream end of the tubular body to the downstream end of the tubular body. The tubular body may further include a folded end portion that forms a first end wall at the upstream end of the tubular body. The first end wall may define an opening that allows airflow between the cavity and the exterior of the tubular body. Preferably, air can flow from the cavity through the opening and into the aerosol-generating element.

[0115] The tubular body may include a second end wall at the downstream end of the tubular body. This second end wall may be formed by folding an end portion of the tubular body at the downstream end of the tubular body. The second end wall may define an opening that also allows airflow between the cavity and the exterior of the tubular body. In the case of the second end wall, the opening may be configured such that air can flow from the exterior of the aerosol-generating article through the opening and into the cavity. Thus, the opening may provide a conduit through which air can be drawn into the aerosol-generating article and through the aerosol-generating substrate.

[0116] In certain embodiments, the material section comprises a coiled sheet defining a plurality of longitudinally extending channels.

[0117] Including such a material segment in the upstream element of an aerosol-generating article according to the present invention can advantageously reduce or prevent aerosol-generating material from migrating from the aerosol-generating element during storage, transport, and use of the aerosol-generating article, while providing an acceptable RTD. Including such a material segment in the upstream element can advantageously reduce or prevent any aerosol-generating material that migrates from the aerosol-generating element from falling into the cavity of the aerosol-generating device during use of the aerosol-generating article. Including such a material segment in the upstream element can advantageously limit or prevent longitudinal movement of the aerosol-generating element during storage, transport, and use of the aerosol-generating article.

[0118] Preferably, the material segment comprises a tubular portion defining an interior region of the upstream element, and the wound sheet is arranged within the tubular portion such that a plurality of longitudinally extending channels are defined in the interior region.

[0119] The wrapped sheet divides the interior area of ​​the upstream element into a plurality of longitudinally extending channels along which air can be drawn through the upstream element. Thus, the wrapped sheet can reduce the cross-sectional area of ​​the empty space in the upstream element into which aerosol-generating material in the aerosol-generating element can migrate, while providing an acceptable RTD. This can be particularly advantageous where the aerosol-generating substrate in the aerosol-generating element comprises a plurality of fragments, pellets, or granules of aerosol-generating material.

[0120] The wound sheet may have a basis weight of up to 200 g / m². Preferably, the wound sheet has a basis weight of less than or equal to 150 g / m². More preferably, the wound sheet has a basis weight of less than or equal to 100 g / m².

[0121] Including a wound sheet having a basis weight of less than or equal to about 100 grams per square meter can allow the wound sheet to have a larger cross-sectional area while maintaining an appropriate overall weight of the upstream component. The wound sheet can thereby divide the interior area of ​​the upstream component into a greater number of longitudinally extending channels while maintaining an appropriate overall weight of the upstream component.

[0122] The wrapped sheet may advantageously act as a barrier to prevent or limit longitudinal movement of the aerosol-generating substrate during storage, transport and use of the aerosol-generating article.

[0123] Therefore, providing an aerosol-generating article comprising an upstream element having the above-described features may improve the quality and consistency of the aerosol delivered to the user compared to known heated tobacco products, and may allow for optimal functioning of the aerosol-generating device of the aerosol-generating system according to the second aspect of the invention.

[0124] The wound sheet comprises a plurality of turns. Preferably, the wound sheet comprises a plurality of non-concentric turns.

[0125] The wound sheet defines a plurality of longitudinally extending channels in an interior region of the upstream element.The wound sheet may have been one or more of rolled, folded, gathered and pleated to define the plurality of longitudinally extending channels.

[0126] As used herein with reference to the present invention, the term "curled" refers to a rolled sheet having a plurality of substantially parallel ridges or corrugations. Preferably, where the rolled sheet has been curled, the substantially parallel ridges or corrugations of the rolled sheet extend in the longitudinal direction of the aerosol-generating article.

[0127] As used herein with reference to the present invention, the term "gathered" means that the sheet material is compressed or contracted substantially transversely with respect to the longitudinal axis of the aerosol-generating article.

[0128] Preferably, the wound sheet has been curled. This can advantageously reduce variations in the cross-sectional area of ​​the plurality of longitudinally extending channels defined by the wound sheet in the interior region of the upstream element.

[0129] Including a rolled wound sheet in the upstream element can advantageously avoid or reduce the presence of longitudinally extending channels having a very large cross-sectional area in the interior region of the upstream element. The presence of longitudinally extending channels having a very large cross-sectional area in the interior region of the upstream element can adversely affect the ability of the upstream element to prevent or restrict upstream movement of aerosol-generating material from the aerosol-generating substrate.

[0130] Including a coiled sheet material that has been curled in the upstream element can advantageously avoid or reduce the presence of longitudinally extending channels having very small cross-sectional areas in the interior region of the upstream element. The presence of longitudinally extending channels having very small cross-sectional areas in the interior region of the upstream element can increase the RTD of the upstream element beyond acceptable or desired levels.

[0131] When the coiled sheet is coiled, adjacent ridges or ripples of the coiled sheet can be spaced apart by less than or equal to about 1.2 mm, less than or equal to about 1 mm, or less than or equal to about 0.8 mm. For example, adjacent ridges or ripples can be spaced apart by less than or equal to about 0.5 mm. The spacing between adjacent ridges or ripples can be selected based on the desired size of the plurality of longitudinally extending channels.

[0132] The rolled sheet may be rolled first and then gathered. That is, the rolled sheet may be a rolled and gathered sheet.

[0133] Typically, the material segment of the upstream element may have a weight of at least 10 mg, preferably at least 20 mg, and more preferably at least 30 mg. The material segment of the upstream element may have a weight of less than or equal to 100 mg, preferably less than or equal to 75 mg, and more preferably less than or equal to 50 mg. In some embodiments, the material segment of the upstream element has a weight of 10 mg to 100 mg, preferably 20 mg to 100 mg, and more preferably 30 mg to 100 mg. In other embodiments, the material segment of the upstream element has a weight of 10 mg to 75 mg, preferably 20 mg to 75 mg, and more preferably 30 mg to 75 mg. In another embodiment, the material segment of the upstream element has a weight of 10 mg to 50 mg, preferably 20 mg to 50 mg, and more preferably 30 mg to 50 mg. In some preferred embodiments, the material segment of the upstream element may have a weight of about 40 mg.

[0134] The RTD of the material segment of the upstream element may be at least about 1 mm H2O, at least about 2 mm H2O, or at least about 4 mm H2O.

[0135] The RTD of the material segment of the upstream element may be less than or equal to about 10 mm H2O, less than or equal to about 8 mm H2O, or less than or equal to about 6 mm H2O.

[0136] The RTD of the material segment of the upstream element may be between about 1 mm H2O and about 10 mm H2O, between about 1 mm H2O and about 8 mm H2O, or between about 1 mm H2O and about 6 mm H2O.

[0137] The RTD of the material segment of the upstream element may be between about 2 mm H2O and about 10 mm H2O, between about 2 mm H2O and about 8 mm H2O, or between about 2 mm H2O and about 8 mm H2O.

[0138] The RTD of the material segment of the upstream element may be between about 4 mm H2O and about 10 mm H2O, between about 4 mm H2O and about 8 mm H2O, or between about 4 mm H2O and about 6 mm H2O.

[0139] In some preferred embodiments, the RTD of the material segment of the upstream element is approximately 5 mm H2O or 5.5 mm H2O.

[0140] In an aerosol-generating article according to the invention, an upstream element as described above is provided upstream of an aerosol-generating element comprising a rod of aerosol-generating substrate defined by a stick pack as previously described. As used herein with reference to the present invention, the term "rod" is used to denote a generally cylindrical element having a generally circular, oval or elliptical cross-section.

[0141] The aerosol-generating element may have a length of at least about 8 mm, at least about 9 mm, or at least about 10 mm.

[0142] The aerosol-generating element may have a length of less than or equal to about 16 mm, less than or equal to about 15 mm, or less than or equal to about 14 mm.

[0143] The aerosol-generating element may have a length of between about 8 mm and about 16 mm, between about 8 mm and about 15 mm, or between about 8 mm and about 14 mm.

[0144] The aerosol-generating element may have a length of between about 9 mm and about 16 mm, between about 9 mm and about 15 mm, or between about 9 mm and about 14 mm.

[0145] The aerosol-generating element may have a length of between about 10 mm and about 16 mm, between about 10 mm and about 15 mm, or between about 10 mm and about 14 mm.

[0146] For example, the aerosol-generating element may have a length of approximately 12 mm.

[0147] The ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article may be at least about 0.10, at least about 0.15 or at least about 0.20.

[0148] The ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article may be less than or equal to about 0.40, less than or equal to about 0.35, or less than or equal to about 0.3.

[0149] The ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article may be between about 0.10 and about 0.40, between about 0.10 and about 0.35, or between about 0.10 and about 0.30.

[0150] The ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article may be between about 0.15 and about 0.40, between about 0.15 and about 0.35, or between about 0.15 and about 0.30.

[0151] The ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article may be between about 0.20 and about 0.40, between about 0.20 and about 0.35, or between about 0.20 and about 0.30.

[0152] Preferably, the aerosol-generating element has a substantially circular cross-section.

[0153] The aerosol-generating element may have an outer diameter of at least about 5 mm, about 6 mm or about 7 mm.

[0154] The aerosol-generating element may have an outer diameter of less than or equal to 12 mm, less than or equal to about 10 mm, or less than or equal to about 8 mm.

[0155] The aerosol-generating element may have an outer diameter of between about 5 mm and about 12 mm, between about 5 mm and about 10 mm, or between about 5 mm and about 8 mm.

[0156] The aerosol-generating element may have an outer diameter of between about 6 mm and about 12 mm, between about 6 mm and about 10 mm, or between about 6 mm and about 8 mm.

[0157] The aerosol-generating element may have an outer diameter of between about 7 mm and about 12 mm, between about 7 mm and about 10 mm, or between about 7 mm and about 8 mm.

[0158] For example, the aerosol-generating element may have an outer diameter of approximately 7.1 mm.

[0159] The aerosol-generating substrate may have a density of at least about 150 mg / cm3, at least about 175 mg / cm3, at least about 200 mg / cm3, or at least about 250 mg / cm3.

[0160] The aerosol-generating substrate may have a density of less than or equal to about 500 mg / cm3, less than or equal to about 450 mg / cm3, less than or equal to about 400 mg / cm3, or less than or equal to about 350 mg / cm3.

[0161] The aerosol-generating substrate may have a density between about 150 mg / cm3 and about 500 mg / cm3, between about 150 mg / cm3 and about 450 mg / cm3, between about 150 mg / cm3 and about 400 mg / cm3, or between about 150 mg / cm3 and about 350 mg / cm3.

[0162] The aerosol-generating substrate may have a density between about 175 mg / cm3 and about 500 mg / cm3, between about 175 mg / cm3 and about 450 mg / cm3, between about 175 mg / cm3 and about 400 mg / cm3, or between about 175 mg / cm3 and about 350 mg / cm3.

[0163] The aerosol-generating substrate may have a density between about 200 mg / cm3 and about 500 mg / cm3, between about 200 mg / cm3 and about 450 mg / cm3, between about 200 mg / cm3 and about 400 mg / cm3, or between about 200 mg / cm3 and about 350 mg / cm3.

[0164] The aerosol-generating substrate may have a density between about 250 mg / cm3 and about 500 mg / cm3, between about 250 mg / cm3 and about 450 mg / cm3, between about 250 mg / cm3 and about 400 mg / cm3, or between about 250 mg / cm3 and about 350 mg / cm3.

[0165] For example, the aerosol-generating substrate may have a density of approximately 300 mg / cm3.

[0166] The RTD of the strip of aerosol-generating substrate may be at least about 4 mm H2O, at least about 5 mm H2O, or at least about 6 mm H2O.

[0167] The RTD of the strip of aerosol-generating substrate may be less than or equal to about 10 mm H2O, less than or equal to about 9 mm H2O, or less than or equal to about 8 mm H2O.

[0168] The RTD of the strip of aerosol-generating substrate may be between about 4 mm H2O and about 10 mm H2O, between about 4 mm H2O and about 9 mm H2O, or between about 4 mm H2O and about 8 mm H2O.

[0169] The RTD of the strip of aerosol-generating substrate may be between about 5 mm H2O and about 10 mm H2O, between about 5 mm H2O and about 9 mm H2O, or between about 5 mm H2O and about 8 mm H2O.

[0170] The RTD of the strip of aerosol-generating substrate may be between about 6 mm H2O and about 10 mm H2O, between about 6 mm H2O and about 9 mm H2O, or between about 6 mm H2O and about 8 mm H2O.

[0171] The aerosol-generating substrate may be a solid aerosol-generating substrate.

[0172] Preferably, the aerosol-generating substrate comprises an aerosol-former.

[0173] The aerosol-forming agent may be any suitable known compound or mixture of compounds that facilitates the formation of a dense and stable aerosol during use. The aerosol-forming agent may facilitate the aerosol being substantially resistant to thermal degradation at temperatures typically applied during use of the aerosol-generating article. Suitable aerosol-forming agents are, for example, polyols such as, for example, triethylene glycol, 1,3-butylene glycol, propylene glycol, and glycerol; esters of polyols such as, for example, glycerol mono-, di-, or triacetate; aliphatic esters of mono-, di-, or polycarboxylic acids such as, for example, dimethyl dodecanedioate and dimethyl tetradecanedioate; and combinations thereof.

[0174] Preferably, the aerosol former comprises one or more of glycerol and propylene glycol. The aerosol former may consist of glycerol or propylene glycol or a combination of glycerol and propylene glycol.

[0175] The aerosol-generating substrate may comprise at least about 5 wt%, at least about 10 wt%, or at least about 12 wt% aerosol-former based on the dry weight of the aerosol-generating substrate.

[0176] The aerosol-generating substrate may comprise less than or equal to about 30 weight percent, less than or equal to about 25 weight percent, or less than or equal to about 20 weight percent aerosol-former, based on the dry weight of the aerosol-generating substrate.

[0177] The aerosol-generating substrate may comprise between about 5 wt% and about 30 wt%, between about 5 wt% and about 25 wt%, or between about 5 wt% and about 20 wt% aerosol-former, based on the dry weight of the aerosol-generating substrate.

[0178] The aerosol-generating substrate may comprise between about 10% to about 30% by weight, between about 10% to about 25% by weight, or between about 10% to about 20% by weight of aerosol-former, based on the dry weight of the aerosol-generating substrate.

[0179] The aerosol-generating substrate may comprise between about 12 wt% and about 30 wt%, between about 12 wt% and about 25 wt%, or between about 12 wt% and about 20 wt% aerosol-former, based on the dry weight of the aerosol-generating substrate.

[0180] The aerosol-generating substrate may comprise a plurality of shreds of tobacco material.The aerosol-generating substrate may comprise a plurality of shreds of homogenised tobacco material.

[0181] As used herein with reference to the present invention, the term "chip" refers to an element having a length that is substantially greater than its width and thickness.

[0182] As used herein with reference to the present invention, the term "homogenised tobacco material" is used to describe a material formed by agglomerating particulate tobacco material.

[0183] Shreds of homogenised tobacco material may be formed from sheets of homogenised tobacco material, for example by cutting or shredding.Rods of homogenised tobacco material may be formed by other methods, for example by extrusion.

[0184] The rod of tobacco material may have a width of at least about 0.3 mm, at least about 0.5 mm, or at least about 0.6 mm.

[0185] The rod of tobacco material may have a width of less than or equal to about 2 mm, less than or equal to about 1.2 mm, or less than about 0.9 mm.

[0186] The rod of tobacco material may have a width of between about 0.3 mm and about 2 mm, between about 0.3 mm and about 1.2 mm, or between about 0.3 mm and about 0.9 mm.

[0187] The rod of tobacco material may have a width of between about 0.5 mm and about 2 mm, between about 0.5 mm and about 1.2 mm, or between about 0.5 mm and about 0.9 mm.

[0188] The rod of tobacco material may have a width of between about 0.6 mm and about 2 mm, between about 0.6 mm and about 1.2 mm, or between about 0.6 mm and about 0.9 mm.

[0189] The rod of tobacco material may have a length of at least about 10 mm.

[0190] The rod of tobacco material may have a length of less than or equal to about 40 millimetres.

[0191] The shreds of tobacco material may have a length of between about 10 mm and about 40 mm.

[0192] At least about 20% by weight on a dry weight basis of the plurality of tobacco material fragments may extend along the entire length of the aerosol-generating substrate.At least about 20% by weight on a dry weight basis of the plurality of tobacco material fragments may have substantially the same length as the length of the aerosol-generating substrate.

[0193] Less than or equal to about 60% by weight on a dry weight basis of the plurality of tobacco material fragments may extend along the entire length of the aerosol-generating substrate.Less than or equal to about 60% by weight on a dry weight basis of the plurality of tobacco material fragments may have a length substantially the same as the length of the aerosol-generating substrate.

[0194] Between about 20% and 60% by weight on a dry weight basis of the plurality of tobacco material fragments may extend along the entire length of the aerosol-generating substrate. Between about 20% and 60% by weight on a dry weight basis of the plurality of tobacco material fragments may have a length that is substantially the same as the length of the aerosol-generating substrate.

[0195] The size of the aerosol-generating material (such as a plurality of tobacco material fragments) of the aerosol-generating substrate can affect the heat distribution within the aerosol-generating substrate. Furthermore, the size of the aerosol-generating material can affect the draw resistance of the article. Furthermore, the size of the aerosol-generating material can affect the ability of the upstream element to prevent or restrict the aerosol-generating material from moving into the longitudinally extending passage of the upstream element. The size of the aerosol-generating material can also affect the ability of the upstream element to prevent or restrict the aerosol-generating material from moving upstream along the longitudinally extending passage and away from the upstream element.

[0196] The aerosol-generating substrate may comprise a plurality of pellets or granules of tobacco material.The aerosol-generating substrate may comprise a plurality of pellets or granules of homogenised tobacco material.

[0197] At least about 60% by weight of the plurality of pellets or granules may have a maximum dimension greater than about 1 mm, at least about 70% by weight of the plurality of pellets or granules may have a maximum dimension greater than about 1 mm, or at least about 80% by weight of the plurality of pellets or granules may have a maximum dimension greater than about 1 mm.

[0198] Where the homogenized plant material is in the form of a plurality of pellets or granules, at least about 70% by weight of the plurality of pellets or granules may have a maximum dimension greater than about 0.5 mm, at least about 80% by weight of the plurality of pellets or granules may have a maximum dimension greater than about 0.5 mm, or at least about 90% by weight of the plurality of pellets or granules may have a maximum dimension greater than about 0.5 mm.

[0199] For example, at least about 80% by weight of the plurality of pellets or granules may have a maximum dimension greater than about 1 mm and at least about 90% by weight of the plurality of pellets or granules may have a maximum dimension greater than about 0.5 mm.

[0200] The aerosol-generating substrate may comprise one or more sheets of tobacco material.

[0201] The aerosol-generating substrate may comprise one or more sheets of homogenised tobacco material.

[0202] The one or more sheets of tobacco material may each individually have a thickness of at least about 100 microns, at least about 150 microns, or at least about 300 microns.

[0203] As used herein with reference to the present invention, individual thickness refers to the thickness of an individual sheet of tobacco material, while combined thickness refers to 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 individual sheets of tobacco material, the combined thickness is the sum of the thicknesses of the two individual sheets of tobacco material, or the measured thickness of the two sheets of tobacco material where the two sheets of tobacco material are stacked in the aerosol-generating substrate.

[0204] The one or more sheets of tobacco material may each individually have a thickness of less than or equal to about 600 microns, less than or equal to about 300 microns, or less than or equal to about 250 microns.

[0205] The one or more sheets of tobacco material may each individually have a thickness of between about 100 microns and about 600 microns, between about 100 microns and about 300 microns, or between about 100 microns and about 250 microns.

[0206] The one or more sheets of tobacco material may each individually have a thickness of between about 150 microns and about 600 microns, between about 150 microns and about 300 microns, or between about 150 microns and about 250 microns.

[0207] The one or more sheets of tobacco material may each individually have a thickness of between about 250 microns and about 600 microns, between about 250 microns and about 300 microns, or between about 250 microns and about 250 microns.

[0208] The one or more sheets of tobacco material may each individually have substantially the same length as the length of the aerosol-generating substrate.

[0209] The one or more sheets of tobacco material may be one or more of curled, folded, gathered and pleated.

[0210] The curling, folding, gathering or pleating of the one or more tobacco material sheets can cause the splitting of the one or more tobacco material sheets to form tobacco material fragments. For example, the one or more tobacco material sheets can be curled to a certain extent so that the integrity of the one or more tobacco material sheets is destroyed at a plurality of parallel ridges or corrugations, causing the material to separate and resulting in the formation of tobacco material fragments.

[0211] The aerosol-generating substrate may comprise a gel composition comprising nicotine, at least one gelling agent and an aerosol-forming agent. The gel composition is preferably substantially free of tobacco.

[0212] The preferred weight ranges for nicotine in the gel composition are the same as those defined above for the aerosol-forming film.

[0213] The gel composition preferably comprises at least 50% by weight of an aerosol former, more preferably at least 60% by weight of an aerosol former, and even more preferably at least 70% by weight of an aerosol former, based on dry weight. The gel composition may comprise up to 80% by weight of an aerosol former. The aerosol former in the gel composition is preferably glycerol.

[0214] The gel composition preferably comprises at least one gelling agent. Preferably, the gel composition comprises a total amount of gelling agent in the range of about 0.4 wt % to about 10 wt %, or about 0.5 wt % to about 8 wt %, or about 1 wt % to about 6 wt %, or about 2 wt % to about 4 wt %, or about 2 wt % to about 3 wt %.

[0215] The term "gelling agent" refers to a compound that, when added to a mixture of 50% by weight water / 50% by weight glycerol in an amount of about 0.3% by weight, homogeneously forms a solid medium or support matrix that results in a gel. Gelling agents include, but are not limited to, hydrogen-bonding crosslinking gelling agents and ionic crosslinking gelling agents.

[0216] The term "hydrogen bond cross-linking gelling agent" refers to a gelling agent that forms non-covalent cross-links or physical cross-links via hydrogen bonds. The hydrogen bond cross-linking gelling agent may include one or more of galactomannan, gelatin, agarose, konjac gum, or agar. The hydrogen bond cross-linking gelling agent may preferably include agar.

[0217] The term "ionic crosslinking gelling agent" refers to a gelling agent that forms non-covalent crosslinks or physical crosslinks through ionic bonds. The ionic crosslinking gelling agent may include low acyl gellan gum, pectin, kappa carrageenan, iota carrageenan, or alginate. The ionic crosslinking gelling agent may preferably include low acyl gellan gum.

[0218] The gelling agent may comprise one or more biopolymers. The biopolymer may be formed from a polysaccharide.

[0219] Biopolymers include, for example, gellan gum (natural, low acyl gellan gum, high acyl gellan gum, preferably low acyl gellan gum), xanthan gum, alginates (alginic acid), agar, guar gum, etc. The composition may preferably include xanthan gum. The composition may include two biopolymers. The composition may include three biopolymers. The composition may include substantially equal weights of the two biopolymers. The composition may include substantially equal weights of the three biopolymers.

[0220] The gel composition may also include a viscosity increasing agent. The viscosity increasing agent in combination with the hydrogen bonding cross-linking gelling agent and the ion bonding cross-linking gelling agent appears to unexpectedly support the solid medium and maintain the gel composition even when the gel composition includes high levels of glycerol.

[0221] The term "viscosity increasing agent" refers to a compound that, when homogeneously added in an amount of 0.3 wt. % to a 50 wt. % water / 50 wt. % glycerol mixture at 25°C, increases viscosity without causing gel formation, the mixture remaining or remaining fluid.

[0222] The gel composition preferably includes a viscosity increasing agent in the range of about 0.2 wt % to about 5 wt %, or about 0.5 wt % to about 3 wt %, or about 0.5 wt % to about 2 wt %, or about 1 wt % to about 2 wt %.

[0223] The viscosity increasing agent may include one or more of xanthan gum, carboxymethyl cellulose, microcrystalline cellulose, methyl cellulose, gum arabic, guar gum, lambda-carrageenan or starch. The viscosity increasing agent may preferably include xanthan gum.

[0224] The gel composition may also include divalent cations. Preferably, the divalent cations include calcium ions, such as calcium lactate in solution. For example, divalent cations (such as calcium ions) can help form a gel in a composition that includes a gelling agent, such as an ionically crosslinked gelling agent. Ionic effects can aid gel formation. The divalent cations can be present in the gel composition in a range of about 0.1% to about 1% by weight, or about 0.5% by weight.

[0225] The gel composition may further comprise an acid. The acid may comprise a carboxylic acid, such as levulinic acid or lactic acid.

[0226] The gel composition preferably includes some water. When the gel composition includes some water, the gel composition is more stable. Preferably, the gel composition includes water in an amount of from about 8% to about 32% by weight, or from about 15% to about 25% by weight, or from about 18% to about 22% by weight, or about 20% by weight.

[0227] Preferably, when a gel composition is used, the aerosol-generating substrate comprises a porous medium loaded with the gel composition.The term "porous" is used herein to refer to a material that provides a plurality of pores or openings that allow air to pass through the material.

[0228] The aerosol-forming matrix may comprise hydroxypropyl methylcellulose and one or more cellulose-based strengthening agents. An aerosol-forming matrix comprising a combination of hydroxypropyl methylcellulose and a cellulose-based strengthening agent may have a number of advantages. Including hydroxypropyl methylcellulose in the aerosol-forming matrix may help improve the manufacturing process of the aerosol-forming matrix. For example, hydroxypropyl methylcellulose may reduce the overall viscosity of the slurry mixed when preparing the aerosol-forming matrix. Compared to conventional slurries, slurries with lower viscosities may flow more easily, and slurries with lower viscosities may be easier to mix, transfer, and handle during the manufacturing process. Including a cellulose-based strengthening agent in the aerosol-forming matrix may increase the tensile strength of the aerosol-forming matrix. For example, an aerosol-forming matrix with a higher tensile strength may be less likely to degrade or break during transportation or during the manufacturing process.

[0229] Additionally, it has been observed that the use of a cellulose-based strengthener to increase the tensile strength of the aerosol-forming substrate can overcome the reduction in tensile strength that may result from the inclusion of hydroxypropyl methylcellulose, while still providing the above-mentioned processing advantages associated with hydroxypropyl methylcellulose.

[0230] In a preferred embodiment, the aerosol-forming substrate may comprise one or more aerosol-forming agents, wherein the aerosol-forming substrate has an aerosol-forming agent content greater than 30% by weight; hydroxypropyl methylcellulose; and one or more cellulose-based strengtheners, wherein the one or more cellulose-based strengtheners include cellulose powder, and wherein the aerosol-forming substrate has a cellulose powder content between about 0.5% by weight and about 50% by weight.

[0231] Including one or more aerosol formers in the aerosol-forming substrate will improve aerosol formation. The one or more aerosol formers may include glycerol. The one or more aerosol formers may include propylene glycol. The one or more aerosol formers may include a combination of glycerol and propylene glycol.

[0232] Preferably, the hydroxypropyl methylcellulose is a low viscosity hydroxypropyl methylcellulose. For example, the hydroxypropyl methylcellulose can have a viscosity of 0.05 Pa / s. In some instances, the hydroxypropyl methylcellulose can have a viscosity of 0.015 Pa / s. In some instances, the hydroxypropyl methylcellulose can have a viscosity between 0.015 Pa / s and 0.05 Pa / s. Advantageously, the use of low viscosity hydroxypropyl methylcellulose can provide benefits during the manufacturing process. The use of low viscosity hydroxypropyl methylcellulose can result in the formation of a low viscosity slurry, which is easier to mix and transfer during manufacturing and processing.

[0233] The one or more cellulose-based strengthening agents may comprise cellulose fibres. Advantageously, cellulose fibres may be a particularly effective cellulose-based strengthening agent in increasing the tensile strength of the aerosol-forming substrate.

[0234] The aerosol-forming matrix comprising hydroxypropyl methylcellulose and one or more cellulose-based enhancers may also contain nicotine. The nicotine may include one or more nicotine salts. The one or more nicotine salts may be selected from the group consisting of nicotine lactate, nicotine citrate, nicotine pyruvate, nicotine bitartrate, nicotine benzoate, nicotine pectinate, nicotine alginate, and nicotine salicylate. The nicotine may include tobacco extract.

[0235] In certain embodiments, the aerosol-forming substrate comprising hydroxypropyl methylcellulose and one or more cellulose-based enhancers may further comprise one or more carboxylic acids, including one or more of fumaric acid, lactic acid, and levulinic acid.

[0236] In certain embodiments, the aerosol-forming substrate comprising hydroxypropyl methylcellulose and one or more cellulose-based enhancers may further comprise tobacco particles. For example, the aerosol-forming substrate may comprise 0.01% by weight of tobacco particles, preferably at least 1% by weight of tobacco particles, even more preferably at least 2% by weight of tobacco particles, and particularly preferably at least 5% by weight of tobacco particles.

[0237] In certain embodiments, the aerosol-forming substrate comprising hydroxypropyl methylcellulose and one or more cellulose-based strengtheners may further comprise carboxymethyl cellulose (CMC). For example, the aerosol-forming substrate may comprise 0.5% by weight of CMC, preferably at least 1% by weight of CMC, more preferably at least 2% by weight of CMC, even more preferably at least 4% by weight of CMC.

[0238] As described above, the aerosol-generating element comprises a stick pack defining a stick of an aerosol-generating substrate.

[0239] The rod pack may comprise a paper packaging material or a non-paper packaging material. In a preferred embodiment, the packaging material of the rod pack comprises paper. Suitable paper packaging materials for use in embodiments of the present invention are known in the art and include, but are not limited to: cigarette paper; and filter segment packaging. Suitable non-paper packaging materials for use in embodiments of the present invention are known in the art and include, but are not limited to, sheets of homogenized tobacco material and sheets of certain polymeric materials. In certain embodiments, the packaging material of the rod pack may be in the form of a laminate comprising a plurality of layers. Preferably, the rod pack does not contain flame retardant compounds.

[0240] The aerosol-generating article may include a susceptor disposed within an aerosol-generating substrate. As used herein with reference to the present invention, the term "susceptor" refers to a material that can convert electromagnetic energy into heat. When placed within a fluctuating electromagnetic field, eddy currents induced in the susceptor cause heating of the susceptor.

[0241] The susceptor is preferably arranged in thermal contact with the aerosol-generating substrate. Thus, when the susceptor becomes hot, the aerosol-generating substrate is heated by the susceptor to generate an aerosol. The susceptor may be arranged in direct physical contact with the aerosol-generating substrate.

[0242] The upstream element may advantageously prevent or limit upstream migration of the susceptor during storage, transport, and use of the aerosol-generating article.

[0243] The susceptor may be an elongate susceptor.

[0244] As used herein with reference to the present invention, the term "elongated" is used to describe a component of an aerosol-generating article having a length that is greater than its width and thickness.

[0245] The elongated susceptor may be arranged generally longitudinally within the aerosol-generating substrate. That is, the longitudinal axis of the elongated susceptor may be generally parallel to the longitudinal axis of the aerosol-generating element. For example, the longitudinal axis of the elongated susceptor may be within plus or minus 10 degrees of being parallel to the longitudinal axis of the aerosol-generating element. The elongated susceptor may be located at a radially central position within the strip of aerosol-generating substrate and extend along the longitudinal axis of the aerosol-generating element.

[0246] The susceptor may extend from a downstream end of the aerosol-generating element towards an upstream end of the aerosol-generating element.

[0247] The susceptor may extend from the upstream end of the aerosol-generating element towards the downstream end of the aerosol-generating element.

[0248] The susceptor may extend from the upstream end of the aerosol-generating substrate towards the downstream end of the aerosol-generating element. That is, the susceptor may extend along the entire length of the aerosol-generating element.

[0249] The length of the susceptor may be substantially the same as the length of the aerosol-generating element.

[0250] The susceptor may extend partially along the length of the aerosol-generating element.

[0251] The susceptor may be spaced from the downstream end of the aerosol-generating substrate.

[0252] The susceptor may be spaced from the upstream end of the aerosol-generating element.

[0253] The susceptor may be spaced from both the downstream end and the upstream end of the aerosol-generating element.

[0254] The length of the susceptor may be less than the length of the aerosol generating element.

[0255] The susceptor may be entirely enclosed within the aerosol-generating substrate. That is, the aerosol-generating substrate may completely surround the susceptor.

[0256] The susceptors may be in the form of needles, strips, ribbons or leaves.

[0257] The susceptor may have a length of at least about 5 mm, at least about 6 mm, or at least about 8 mm.

[0258] The susceptor may have a length of less than or equal to about 15 mm, less than or equal to about 12 mm, or less than or equal to about 10 mm.

[0259] The susceptor may have a length between about 5 mm and about 15 mm, between about 5 mm and about 12 mm, or between about 5 mm and about 10 mm.

[0260] The susceptor may have a length between about 6 mm and about 15 mm, between about 6 mm and about 12 mm, or between about 6 mm and about 10 mm.

[0261] The susceptor may have a length between about 8 mm and about 15 mm, between about 8 mm and about 12 mm, or between about 8 mm and about 10 mm.

[0262] The susceptor may have a width of at least about 1 mm.

[0263] The susceptor may have a width of less than or equal to about 5 mm.

[0264] The susceptor may have a width between about 1 mm and about 5 mm.

[0265] The susceptor may have a thickness of at least about 0.01 mm or at least about 0.5 mm.

[0266] The susceptor may have a thickness of less than or equal to about 2 millimeters, less than or equal to about 500 microns, or less than or equal to about 100 microns.

[0267] The susceptor may have a thickness between about 10 microns and about 2 mm, between about 10 microns and about 500 microns, or between about 10 microns and about 100 microns.

[0268] The susceptor may have a thickness between about 0.5 mm and about 2 mm.

[0269] The susceptor may have a generally circular cross-section.

[0270] The susceptor may have a substantially constant cross-section along the length of the susceptor.

[0271] If the susceptor is in the form of a strip or blade, the strip or blade may have a rectangular shape having a width of between about 2 mm and about 8 mm or between about 3 mm and about 5 mm. For example, the susceptor in the form of a strip or blade may have a width of about 4 mm.

[0272] If the susceptor is in the form of a strip or blade, the strip or blade may have a rectangular shape and a thickness between about 0.03 mm and about 0.15 mm or between about 0.05 mm and about 0.09 mm. For example, the susceptor in the form of a strip or blade may have a thickness of about 0.07 mm or about 0.06 mm.

[0273] The susceptor may be formed from any material that can be inductively heated to a temperature sufficient to generate an aerosol from the aerosol-generating substrate. For example, the susceptor may comprise metal or carbon.

[0274] The susceptor may comprise or be composed of a ferromagnetic material, such as a ferromagnetic alloy, ferritic iron, or ferromagnetic steel or stainless steel. Suitable susceptors may be or include aluminum. The susceptor may be formed from 400 series stainless steel, such as grade 410, 420, or 430 stainless steel. Different materials will dissipate different amounts of energy when placed within an electromagnetic field having similar frequency and field strength values.

[0275] Thus, the parameters of the susceptor such as material type, length, width and thickness can all be modified to provide a desired power dissipation within a known electromagnetic field.The susceptor can be heated to temperatures in excess of 250 degrees Celsius.

[0276] Suitable susceptors may include a non-metallic core having a metal layer disposed on the non-metallic core, such as metal traces formed on the surface of a ceramic core. The susceptor may have an outer protective layer, such as a ceramic protective layer or a glass protective layer, encapsulating the susceptor. The susceptor may include a protective coating formed of glass, ceramic, or an inert metal formed on the core of the susceptor material.

[0277] The susceptor may be a multi-material susceptor and may include a first susceptor material and a second susceptor material.

[0278] Aerosol-generating articles according to the invention may further comprise a downstream section downstream of the aerosol-generating element. Where present, the downstream section is arranged immediately downstream of the aerosol-generating element and extends from the downstream end of the aerosol-generating element to the downstream end of the aerosol-generating article.

[0279] The downstream section may include one or more components.

[0280] For example, the downstream section may include one or more of a support element, an aerosol-cooling element, a mouthpiece element.

[0281] At least one of the support element and the aerosol-cooling element may be in the form of a hollow tubular element. In some embodiments, both the support element and the aerosol-cooling element are in the form of hollow tubular elements, which may differ in length, inner diameter, or both.

[0282] In the aerosol generating article according to the present invention, such hollow tubular elements provide an unrestricted flow channel. This means that the hollow tubular elements provide a negligible RTD level. As used herein with reference to the present invention, the term "negligible RTD level" is used to describe an RTD less than 1 mm H2O / 10 mm length of a hollow tubular matrix element, less than 0.4 mm H2O / 10 mm length of a hollow tubular matrix element or less than 0.1 mm H2O / 10 mm length of a hollow tubular matrix element. Therefore, the flow channel should not contain any components that would hinder the flow of air in the longitudinal direction. Preferably, the flow channel is substantially empty.

[0283] The hollow tubular element may have a total length of at least about 6 mm, preferably at least about 8 mm, at least about 10 mm, at least about 12 mm, or at least about 15 mm.

[0284] The hollow tubular element can have an overall length of less than or equal to about 30 mm, less than or equal to about 25 mm, or less than or equal to about 23 mm.

[0285] The hollow tubular element may have an overall length of between about 10 mm and about 30 mm, between about 10 mm and about 25 mm, or between about 10 mm and about 23 mm.

[0286] The hollow tubular element may have an overall length of between about 12 mm and about 30 mm, between about 12 mm and about 25 mm, or between about 12 mm and about 23 mm.

[0287] The hollow tubular element may have an overall length of between about 12 mm and about 30 mm, between about 12 mm and about 25 mm, or between about 12 mm and about 23 mm.

[0288] The overall length of the hollow tubular element may be selected based on the desired overall length of the aerosol-generating article.

[0289] The hollow tubular element can be formed from any suitable material or combination of materials. For example, the hollow tubular element 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.

[0290] In some embodiments, a ventilation zone may be provided at a location downstream of the aerosol-generating element. By providing a ventilation zone at a location along the hollow tubular element itself or along an intermediate element disposed between the hollow tubular element and the downstream end of the aerosol-generating article, satisfactory cooling of the aerosol stream generated upon heating the aerosol-generating substrate and drawn through the hollow tubular element may be achieved. Without wishing to be bound by theory, the temperature drop caused by admitting cooler outside air into the aerosol-generating article downstream of the aerosol-generating element via the ventilation zone may have a beneficial effect on the nucleation and growth of aerosol particles.

[0291] The ventilation zone may comprise a plurality of perforations extending through the tubular wall of the hollow tubular element. The ventilation zone may comprise at least one row of circumferential perforations. The ventilation zone may comprise two rows of circumferential perforations. For example, the perforations may be formed on a production line during manufacture of the aerosol-generating article. Each row of circumferential perforations may comprise 8 to 30 perforations.

[0292] As described above, the downstream section of the aerosol-generating article may comprise a mouthpiece element located downstream of the aerosol-generating substrate and at the downstream or mouth or proximal end of the aerosol-generating article.

[0293] The mouthpiece element may be a mouthpiece filter element. The mouthpiece element may include at least one filter segment. For example, the mouthpiece element may include one or more segments of fibrous filter material. Suitable fibrous filter materials are known in the art. For example, the at least one mouthpiece filter segment may include a cellulose acetate filter segment formed from cellulose acetate tow.

[0294] The mouthpiece element may consist of a single filter segment.The mouthpiece element may comprise two or more filter segments axially aligned with each other in abutting end-to-end relationship.

[0295] Parameters or characteristics described herein with respect to the mouthpiece element as a whole may equally apply to the filter segment of the mouthpiece element.

[0296] The mouthpiece element may have low particle filtration efficiency.

[0297] The mouthpiece element may have an RTD of less than or equal to about 25 mm H20, less than or equal to about 20 mm H20, or less than or equal to about 15 mm H20.

[0298] The mouthpiece element may have an RTD of at least about 10 mm H20.

[0299] The mouthend element may have an RTD of between about 10 mm H2O and about 25 mm H2O, or between about 10 mm H2O and about 20 mm H2O, or between about 10 mm H2O and about 15 mm H2O.

[0300] Preferably, the mouthend element has a generally circular cross-section.

[0301] Preferably, the mouthpiece element has an outer diameter that is substantially the same as the outer diameter of the aerosol-generating article.

[0302] The mouthend element may have a length of at least about 3 mm or at least about 5 mm.

[0303] The length of the mouthend element may be less than or equal to about 14 mm, preferably less than or equal to 12 mm, less than or equal to 10 mm or less than or equal to about 9 mm.

[0304] The length of the mouthend element may be between about 3 mm and about 11 mm or between about 3 mm and about 9 mm.

[0305] The length of the mouthend element may be between about 5 mm and about 11 mm or between about 5 mm and about 9 mm.

[0306] For example, the mouthpiece element may be approximately 7 mm in length.

[0307] The length of the mouthend element may be selected based on the desired overall length of the aerosol-generating article.

[0308] The mouthend element may be defined by the stick wrap.

[0309] The mouthpiece element may be non-ventilated, such that air does not enter the aerosol-generating article along the mouthpiece element.

[0310] The mouthend element may be connected to one or more adjacent components of the aerosol-generating article by means of a tipping wrapper.

[0311] The aerosol-generating article may define a mouth-end cavity at the downstream end of the aerosol-generating article. For example, the mouthpiece element itself may be in the form of a hollow tubular element. Alternatively, the mouthpiece element may include a non-hollow segment immediately upstream of the hollow tubular segment provided at the downstream end of the mouthpiece element. As yet another alternative, the mouth-end cavity may be defined by an outer wrapper of the mouthpiece element, the outer wrapper extending beyond the downstream end of the filter material segment of the mouthpiece element.

[0312] The aerosol-generating article may have an overall length of at least about 35 mm, at least about 38 mm, at least about 40 mm, or at least about 42 mm.

[0313] The aerosol-generating article may have an overall length of less than or equal to about 100 mm, less than or equal to about 70 mm, less than or equal to about 60 mm, or less than or equal to about 50 mm.

[0314] The aerosol-generating article may have an overall length of between about 35 mm and about 100 mm, between about 35 mm and about 70 mm, between about 35 mm and about 60 mm, or between about 35 mm and about 50 mm.

[0315] The aerosol-generating article may have a total length of between about 38 mm and about 100 mm, between about 38 mm and about 70 mm, between about 38 mm and about 60 mm, or between about 38 mm and about 50 mm.

[0316] The aerosol-generating article may have an overall length of between about 40 mm and about 100 mm, between about 40 mm and about 70 mm, between about 40 mm and about 60 mm, or between about 40 mm and about 50 mm.

[0317] The aerosol-generating article may have an overall length of between about 42 mm and about 100 mm, between about 42 mm and about 70 mm, between about 42 mm and about 60 mm, or between about 42 mm and about 50 mm.

[0318] For example, the aerosol-generating article may have an overall length of approximately 45 mm.

[0319] Preferably, the aerosol-generating article has a substantially circular cross-section.

[0320] The aerosol-generating article may have an outer diameter of at least about 5 mm, at least about 6 mm, or at least about 7 mm.

[0321] The aerosol-generating article may have an outer diameter of less than or equal to about 12 mm, less than or equal to about 10 mm, or less than or equal to about 8 mm.

[0322] The aerosol-generating article may have an outer diameter of between about 5 mm and about 12 mm, between about 5 mm and about 10 mm, or between about 5 mm and about 8 mm.

[0323] The aerosol-generating article may have an outer diameter of between about 6 mm and about 12 mm, between about 6 mm and about 10 mm, or between about 6 mm and about 8 mm.

[0324] The aerosol-generating article may have an outer diameter of between about 7 mm and about 12 mm, between about 7 mm and about 10 mm, or between about 7 mm and about 8 mm.

[0325] For example, the aerosol-generating article may have an outer diameter of approximately 7.1 mm.

[0326] According to a second aspect of the invention, there is provided an aerosol-generating system comprising: an aerosol-generating article according to the first aspect of the invention; and an aerosol-generating device configured to heat an aerosol-generating substrate of the aerosol-generating article.

[0327] The aerosol-generating device comprises means for heating the aerosol-generating substrate to a temperature sufficient to generate an aerosol from the aerosol-generating substrate. Preferably, the aerosol-generating device comprises a housing defining a cavity configured to receive an aerosol-generating article, and means for heating the aerosol-generating substrate to a temperature sufficient to generate an aerosol from the aerosol-generating substrate when the aerosol-generating article is received in the cavity.

[0328] The aerosol generating device may be a handheld aerosol generating device.

[0329] The aerosol generating device may be an electrically operated aerosol generating device.

[0330] The aerosol generating device may comprise a power supply and control electronics.

[0331] The aerosol generating device may comprise a battery and control electronics.

[0332] The aerosol-generating device may be configured to heat the aerosol-generating substrate from the inside. That is, the aerosol-generating device may be configured to supply heat to the aerosol-generating substrate from a location inside the aerosol-generating article.

[0333] For example, in some embodiments, the aerosol-generating device comprises a heater element configured to be inserted into the aerosol-generating element when the aerosol-generating article is received within the cavity of the aerosol-generating device.

[0334] In other embodiments, the aerosol-generating article comprises a susceptor element disposed at a position within the aerosol-generating element, and the aerosol-generating device comprises an inductor coil positioned on or within the housing, the power supply of the aerosol-generating device being connected to the inductor coil and being configured to provide a high-frequency oscillating current to the inductor coil. This generates an alternating magnetic field that induces a voltage in the susceptor element. The induced voltage causes a current to flow in the susceptor element, and the current causes Joule heating of the susceptor element, which in turn heats the aerosol-generating substrate. The aerosol-generating device may be capable of generating a fluctuating electromagnetic field having a magnetic field strength (H field strength) between 1 and 5 kiloamperes per meter (kAm), preferably between 2 and 3 kA / m, for example, about 2.5 kA / m.

[0335] The aerosol-generating device may be configured to heat the aerosol-generating substrate externally. That is, the aerosol-generating device may be configured to supply heat to the aerosol-generating substrate from a location external to the aerosol-generating article. For example, in some embodiments, the aerosol-generating device includes a heater element positioned around the periphery of the cavity and configured to heat the aerosol-generating substrate of the aerosol-generating article from the exterior of the aerosol-generating element of the aerosol-generating article.

[0336] The present invention is defined in the claims. However, a non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples may be combined with any one or more features of another example, embodiment or aspect described herein.

[0337] Examples

[0338] Example Ex1: An aerosol-generating article for generating an aerosol upon heating, the aerosol-generating article comprising: an aerosol-generating element comprising a strip of an aerosol-generating substrate defined by a stick pack; an upstream element positioned upstream of the aerosol-generating element, wherein the upstream element comprises a material segment defined by a first wrapper; and a second wrapper defining both the upstream element and the aerosol-generating element. The first wrapper, the second wrapper, or both comprise a flame retardant coating composition comprising one or more flame retardant compounds at a location along the material segment of the upstream element.

[0339] Example Ex2: An aerosol-generating article according to Example Ex1, wherein the first packaging comprises a packaging base material, and the flame retardant composition is arranged on the surface of the material segment of the packaging base material facing the upstream element, the surface of the material segment of the packaging base material facing away from the upstream element, or both.

[0340] Example Ex3: An aerosol-generating article according to example Ex1, wherein the first packaging comprises a packaging base material impregnated with the flame retardant composition.

[0341] Example Ex4: An aerosol-generating article according to example Ex1, wherein the second packaging comprises a packaging base material impregnated with the flame retardant composition.

[0342] Example Ex5: An aerosol-generating article according to example Ex1, wherein the first packaging comprises a packaging base material including the flame retardant composition.

[0343] Example Ex6: An aerosol-generating article according to example Ex1, wherein the second packaging comprises a packaging base material including the flame retardant composition.

[0344] Example Ex7: An aerosol-generating article according to any one of Examples Ex1 to Ex6, wherein the flame retardant composition comprises a polymer and a mixed salt based on at least one monocarboxylic acid, dicarboxylic acid and / or tricarboxylic acid, at least one polyphosphoric acid, pyrophosphoric acid and / or phosphoric acid, and a hydroxide or salt of an alkali metal or alkaline earth metal, wherein the at least one monocarboxylic acid, dicarboxylic acid and / or tricarboxylic acid forms a carboxylate with the hydroxide or salt, and the at least one polyphosphoric acid, pyrophosphoric acid and / or phosphoric acid forms a phosphate with the hydroxide or salt.

[0345] Example Ex8: An aerosol-generating article according to example Ex7, wherein the flame retardant composition comprises a carbonate of an alkali metal or an alkaline earth metal.

[0346] Example Ex9: An aerosol-generating article according to any one of Examples Ex1 to Ex6, wherein the flame retardant composition comprises at least one C 10 Or higher fatty acids, tall oil fatty acids (TOFA), phosphorylated linseed oil, phosphorylated downstream corn oil modified cellulose.

[0347] Example Ex10: An aerosol-generating article according to any of the preceding examples, wherein neither the first package nor the second package comprises metal.

[0348] Example Ex11: An aerosol-generating article according to any one of Examples Ex2 to Ex10, wherein the flame retardant composition is applied as a coating on at least one side of the packaging base material of the package by a size press, spraying, printing or coating based application process.

[0349] Example Ex12: An aerosol-generating article according to any one of Examples Ex2 to Ex11, wherein the packaging base material of the first package or the second package or both is a paper material having a weight of 20 gsm to 110 gsm, preferably 20 gms to 40 gsm.

[0350] Example Ex 13: An aerosol-generating article according to any of the preceding examples, wherein the material segment comprises a rod of cellulose acetate.

[0351] Example Ex 14: An aerosol-generating article according to any of the preceding examples, wherein the material segment comprises a hollow tubular body.

[0352] Example Ex 15: An aerosol-generating article according to any one of the preceding examples, wherein the material segment comprises a rolled sheet defining a plurality of longitudinally extending channels.

[0353] Example Ex16: An aerosol-generating article according to example Ex15, wherein the material segment comprises a tubular portion defining an interior region of the upstream element, and the wound sheet is arranged within the tubular portion such that the plurality of longitudinally extending channels are defined in the interior region.

[0354] Example Ex 17: An aerosol-generating article according to example Ex 15 or Ex 16, wherein the wound sheet has a basis weight of less than or equal to about 100 g / m 2 .

[0355] Example Ex 18: An aerosol-generating article according to any one of the preceding examples, wherein the aerosol-generating substrate comprises at least 10% by weight of an aerosol-former.

[0356] Example Ex 19: An aerosol-generating article according to any one of Examples Ex 1 to Ex 18, wherein the aerosol-generating substrate comprises a plurality of shreds of tobacco material.

[0357] Example Ex20: An aerosol-generating article according to any one of Examples Ex1 to Ex18, wherein the aerosol-generating substrate comprises a plurality of pellets or granules of tobacco material.

[0358] Example Ex21: An aerosol-generating article according to any one of Examples Ex1 to Ex18, wherein the aerosol-generating substrate comprises one or more sheets of homogenised tobacco material.

[0359] Example Ex22: An aerosol-generating article according to any one of Examples Ex1 to Ex18, wherein the aerosol-generating substrate comprises a gel composition comprising nicotine, at least one gelling agent, and an aerosol-forming agent.

[0360] Example Ex23: An aerosol-generating article according to any one of Examples Ex1 to Ex18, wherein the aerosol-generating matrix comprises hydroxypropyl methylcellulose and one or more cellulose-based strengtheners.

[0361] Example Ex24: An aerosol-generating article according to any one of the preceding examples, wherein the stick pack contains no flame retardant compound.

[0362] Example Ex25: An aerosol-generating article according to any one of Examples Ex2 to Ex24, wherein the packaging base material of the first package has a basis weight of 20 g / m2 to 120 g / m2.

[0363] Example Ex26: An aerosol-generating article according to any one of Examples Ex2 to Ex24, wherein the packaging base material of the first package has a thickness of 20 micrometers to 110 micrometers.

[0364] Example Ex27: An aerosol-generating article according to any one of Examples Ex2 to Ex24, wherein the packaging base material of the second package has a basis weight of 20 g / m2 to 60 g / m2.

[0365] Example Ex28: An aerosol-generating article according to any one of Examples Ex2 to Ex24, wherein the packaging base material of the second package has a thickness of 40 to 70 microns.

[0366] Example Ex29: The aerosol-generating article according to any of the preceding examples, wherein the ratio of the total weight of the flame retardant compound(s) to the overall dry basis weight of the package may be at least about 0.02.

[0367] Example Ex30: The aerosol-generating article according to any one of the preceding examples, wherein the ratio of the total weight of the flame retardant compound(s) to the overall dry basis weight of the package is less than or equal to about 0.20.

[0368] Example Ex31: An aerosol-generating article according to any of the preceding examples, wherein the flame retardant composition is disposed in a treated portion of the wrapper, the treated portion of the wrapper extending over at least 10% of the outer surface of the material segment of the upstream element.

[0369] Example Ex31: An aerosol-generating article according to any of the preceding examples, wherein the flame retardant composition is disposed in a treated portion of the wrapper, the treated portion of the wrapper extending over at least 40% of the outer surface of the material segment of the upstream element.

[0370] Example Ex32: An aerosol-generating article according to any of the preceding examples, wherein the flame retardant composition is disposed in a treated portion of the wrapper, the treated portion of the wrapper extending over at least 80% of the outer surface of the material segment of the upstream element.

[0371] Example Ex34: An aerosol-generating article according to any of the preceding examples, wherein the flame retardant composition is disposed in a treated portion of the wrapper, the treated portion of the wrapper extending over at least 90% of the outer surface of the material segment of the upstream element.

[0372] Example Ex35: An aerosol-generating article according to any of the preceding examples, wherein the flame retardant composition is disposed in a treated portion of the wrapper, the treated portion of the wrapper extending over at least 95% of the outer surface of the material segment of the upstream element.

[0373] Example Ex36: An aerosol-generating article according to any one of the preceding examples, wherein the flame retardant composition is disposed in a treated portion of the wrapper, the treated portion of the wrapper having a length of at least 10% of the length of the material segment of the upstream element.

[0374] Example Ex37: An aerosol-generating article according to any one of the preceding examples, wherein the flame retardant composition is disposed in a treated portion of the wrapper, the treated portion of the wrapper having a length of at least 40% of the length of the material segment of the upstream element.

[0375] Example Ex38: An aerosol-generating article according to any one of the preceding examples, wherein the flame retardant composition is disposed in a treated portion of the wrapper, the treated portion of the wrapper having a length of at least 80% of the length of the material segment of the upstream element.

[0376] Example Ex39: An aerosol-generating article according to any one of the preceding examples, wherein the flame retardant composition is disposed in a treated portion of the wrapper, the treated portion of the wrapper having a length of at least 90% of the length of the material segment of the upstream element.

[0377] Example Ex40: An aerosol-generating article according to any of the preceding examples, wherein the flame retardant composition is disposed in a treated portion of the wrapper, the treated portion of the wrapper having a length of at least 95% of the length of the material segment of the upstream element.

[0378] Example Ex41: An aerosol-generating article according to any of the preceding examples, wherein the flame retardant composition is disposed in the treated portion of the package, at least about 10 grams of the flame retardant composition being disposed in the treated portion per square meter of treated portion surface area.

[0379] Example Ex42: An aerosol-generating article according to any one of the preceding examples, wherein the flame retardant composition is disposed in the treated portion of the package, with less than or equal to 100 grams of the flame retardant composition disposed in the treated portion per square meter of treated portion surface area.

[0380] Example Ex43: An aerosol-generating article according to any of the preceding examples, wherein the flame retardant composition is disposed in a treated portion of the packaging, and the content of the one or more flame retardant compounds in the treated portion is such that the aerosol-generating article does not ignite when the aerosol-generating article is heated at 500 degrees Celsius for at least 5 seconds using a resistive heating coil.

[0381] Example Ex44: An aerosol-generating article according to any of the preceding examples, wherein the flame retardant composition is disposed in a treated portion of the packaging, and the content of the one or more flame retardant compounds in the treated portion is such that the aerosol-generating article does not ignite when the aerosol-generating article is heated at 500 degrees Celsius for at least 30 seconds using a resistive heating coil.

[0382] Example Ex45: An aerosol-generating article according to any one of the preceding examples, wherein the upstream element has an outer diameter of at least 5 mm.

[0383] Example Ex46: An aerosol-generating article according to any one of the preceding examples, wherein the upstream element has an outer diameter less than or equal to 12 mm.

[0384] Example Ex47: An aerosol-generating article according to any one of the preceding examples, wherein the upstream element has a length of at least 1 mm.

[0385] Example Ex48: An aerosol-generating article according to any one of the preceding examples, wherein the upstream element has a length less than or equal to 25 mm.

[0386] Example Ex49: An aerosol-generating article according to any one of the preceding examples, wherein the upstream element has a weight of at least 10 mg.

[0387] Example Ex50: An aerosol-generating article according to any one of the preceding examples, wherein the upstream element has a weight less than or equal to 100 mg.

[0388] Example Ex51: An aerosol-generating article according to any of the preceding examples, wherein the material segment of the upstream element has an RTD of at least 1 mm H20.

[0389] Example Ex52: An aerosol-generating article according to any of the preceding examples, wherein the material segment of the upstream element has an RTD of less than or equal to 10 mm H20.

[0390] Example Ex53: An aerosol generating system, comprising an electrically operated aerosol generating device and an aerosol generating article according to any one of Examples Ex1 to Ex52, wherein the aerosol generating device comprises a device for heating the aerosol generating substrate to a temperature sufficient to generate an aerosol from the aerosol generating substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0391] Examples will now be further described with reference to the figures of the accompanying drawings, in which:

[0392] Figure 1shows a schematic side cross-sectional view of an aerosol-generating article according to one embodiment of the present invention; and

[0393] Figure 2 A schematic side cross-sectional view of another aerosol-generating article according to another embodiment of the invention is shown. DETAILED DESCRIPTION

[0394] Figure 1 The aerosol-generating article 10 shown in FIG. 1 comprises a strip 12 of aerosol-generating substrate 12 and a downstream section 14 at a position downstream of the strip 12 of aerosol-generating substrate. In addition, the aerosol-generating article 10 comprises an upstream section 16 at a position upstream of the strip 12 of aerosol-generating substrate. Thus, the aerosol-generating article 10 extends from an upstream end or distal end 18 to a downstream end or mouth end 20.

[0395] The aerosol-generating article has an overall length of approximately 45 mm.

[0396] The downstream section 14 comprises a support element 22 positioned immediately downstream of the strip 12 of aerosol-generating substrate, the support element 22 being longitudinally aligned with the strip 12. Figure 1 In the embodiment of FIG, the upstream end of the support element 18 abuts the downstream end of the strip 12 of aerosol-generating substrate. In addition, the downstream section 14 includes an aerosol-cooling element 24 positioned immediately downstream of the support element 22, the aerosol-cooling element 24 being longitudinally aligned with the strip 12 and the support element 22. Figure 1 In the embodiment of FIG, the upstream end of the aerosol-cooling element 24 abuts the downstream end of the support element 22. Figure 1 In the embodiment of FIG. 8 , the support element 22 and the aerosol-cooling element 24 together define a central hollow section 80 of the aerosol-generating article 10 .

[0397] The support element 22 includes a first hollow tubular segment 26. The first hollow tubular segment 26 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The first hollow tubular segment 26 defines an interior cavity 28 extending from an upstream end 30 of the first hollow tubular segment to a downstream end 32 of the first hollow tubular segment 20. The interior cavity 28 is substantially hollow, and thus substantially unrestricted airflow is achieved along the interior cavity 28.

[0398] The first hollow tubular segment 26 has a length of about 8 mm, an outer diameter of about 7.25 mm, and an inner diameter of about 1.9 mm. Therefore, the thickness of the peripheral wall of the first hollow tubular segment 26 is about 2.67 mm.

[0399] The aerosol-cooling element 24 includes a second hollow tubular segment 34. The second hollow tubular segment 34 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The second hollow tubular segment 34 defines an interior cavity 36 extending from an upstream end 38 of the second hollow tubular segment to a downstream end 40 of the second hollow tubular segment 34. The interior cavity 36 is substantially hollow, and thus substantially unrestricted airflow is achieved along the interior cavity 36.

[0400] The second hollow tubular segment 34 has a length of approximately 8 mm, an outer diameter of approximately 7.25 mm, and an inner diameter of approximately 3.25 mm. Thus, the thickness of the peripheral wall of the second hollow tubular segment 34 is approximately 2 mm. Thus, the ratio between the inner diameter of the first hollow tubular segment 26 and the inner diameter of the second hollow tubular segment 34 is approximately 0.75.

[0401] The aerosol-generating article 10 comprises a ventilation zone 60 disposed at a position along the second hollow tubular segment 34. In more detail, the ventilation zone is disposed approximately 2 mm from the upstream end of the second hollow tubular segment 34. The ventilation level of the aerosol-generating article 10 is approximately 25%.

[0402] exist Figure 1 In the embodiment of the present invention, the downstream section 14 further comprises a mouthpiece element 42 at a position downstream of the intermediate hollow section 80. In more detail, the mouthpiece element 42 is positioned immediately downstream of the aerosol-cooling element 24. Figure 1 As shown in the Figures, the upstream end of the mouthpiece element 42 abuts the downstream end 40 of the aerosol-cooling element 24.

[0403] The mouthpiece member 42 is provided in the form of a low density cellulose acetate cylindrical rod 44. The mouthpiece member 42 has a length of approximately 12 mm and an outer diameter of approximately 7.25 mm.

[0404] The strip 12 comprises an aerosol-generating substrate of one of the types described above.

[0405] The rod 12 of aerosol-generating substrate had an outer diameter of approximately 7.25 mm and a length of approximately 12 mm.

[0406] The aerosol-generating article 10 further comprises an elongated susceptor 46 within the strip 12 of aerosol-generating substrate. In more detail, the susceptor 46 is arranged generally longitudinally within the aerosol-generating substrate so as to be generally parallel to the longitudinal direction of the strip 12. Figure 1 As shown in the figures, the susceptor 46 is positioned in a radially central position within the strip and effectively extends along the longitudinal axis of the strip 12. In more detail, the susceptor 46 is in thermal contact with the aerosol-generating substrate. The susceptor 46 extends from the upstream end to the downstream end of the strip 12. In practice, the susceptor 46 has substantially the same length as the strip 12 of aerosol-generating substrate.

[0407] exist Figure 1 In the embodiment of FIG. 4 , the susceptor 46 is provided in the form of a strip and has a length of about 12 mm, a thickness of about 60 microns, and a width of about 4 mm.

[0408] The upstream section 16 comprises an upstream element 48 positioned immediately upstream of the strip 12 of aerosol-generating substrate, the upstream element 48 being longitudinally aligned with the strip 12. Figure 1 In the embodiment of the invention, the downstream end of the upstream element 48 abuts the upstream end of the strip of aerosol-generating substrate 12. This advantageously prevents displacement of the susceptor 46. Furthermore, this ensures that the consumer does not accidentally come into contact with the heated susceptor 46 after use.

[0409] The upstream element 48 comprises a material segment 50 in the form of a cylindrical rod of cellulose acetate and a first packaging 52 defining the material segment 50. The material segment 50 has a length of approximately 5 mm. The RTD of the material segment 50 is approximately 30 mm H2O.

[0410] The aerosol-generating article 10 further comprises a composite wrapper 54 that attaches the upstream element 48 to the remaining components of the aerosol-generating article. Figure 1 In the embodiment of FIG. 5 , a single combination package 54 is depicted that defines the upstream element 48 , the strip 12 , and the downstream section 14 and holds them together to form the aerosol-generating article.

[0411] However, it will be apparent that alternative configurations are also possible in which two or more combination wrappers are employed to assemble different components of the aerosol-generating article. For example, a first combination wrapper may be used to attach the support element 22 to the aerosol-cooling element 24, and the resulting assembly may then be attached to the upstream section 16 and the strip 12 by means of a second combination wrapper. The resulting component assembly may then be attached to the mouthpiece element 42 by means of a tipping wrapper.

[0412] The first wrapper 52 comprises a flame retardant composition at a location along the material segment 50. In more detail, the first wrapper 52 is formed from a packaging base material having a flame retardant coating applied on a surface of the packaging base material facing the material segment 50.

[0413] In more detail, the flame retardant coating is provided in at least the treated portion of the first wrapper 52 extending between the proximal end and the distal end of the material segment 50. The treated portion contains about 15 grams of the flame retardant compound per square meter of the treated portion surface area. Thus, the treated portion of the wrapper 52 has an overall basis weight that is greater than the basis weight of the base material of the wrapper. Figure 1 In the embodiment of , the treated portion has a length that substantially matches the length of the material segment 50 and extends over substantially the entire outer surface area of ​​the material segment 50 .

[0414] like Figure 1 , the aerosol-generating article 10 further comprises a wrapper 70 that defines the strip 12 of aerosol-generating substrate. The wrapper 70 is separate and distinct from the first wrapper 52 that defines the material segment 50. Neither the first wrapper 52 nor the wrapper 70 comprises metal foil. The combined wrapper 54 described above defines both the first wrapper 52 that defines the material segment 50 and the wrapper 70 that defines the strip 12 of aerosol-generating substrate.

[0415] Figure 2 The aerosol generating article 110 shown in FIG. Figure 1 The invention shares many features with the aerosol-generating article 10 of the present invention and will be described below in terms of how it differs from the aerosol-generating article 10.

[0416] like Figure 2 As shown in , the aerosol-generating article 110 comprises a strip 12 of aerosol-generating substrate 12 and a modified downstream section 114 at a position downstream of the strip 12 of aerosol-generating substrate.

[0417] and Figure 1 Similar to the downstream section 14 of the aerosol-generating article 10, Figure 2 The modified downstream section 114 of the aerosol-generating article 110 comprises a support element 22 positioned immediately downstream of the strip 12 of aerosol-generating substrate, the support element 22 being longitudinally aligned with the strip 12, wherein the upstream end of the support element 22 abuts the downstream end of the strip 12 of aerosol-generating substrate.

[0418] Furthermore, the modified downstream section 114 includes an aerosol-cooling element 134 positioned immediately downstream of the support element 22, the aerosol-cooling element 134 being longitudinally aligned with the strip 12 and the support element 22. In more detail, the upstream end of the aerosol-cooling element 134 abuts the downstream end of the support element 22.

[0419] In contrast to the downstream section 14 of the aerosol-generating article 10, the aerosol-cooling element 134 of the modified downstream section 114 comprises a plurality of longitudinally extending channels that provide low or substantially zero resistance to the passage of air therethrough. In more detail, the aerosol-cooling element 134 is formed from a preferably non-porous sheet material selected from the group consisting of metal foil, polymer sheet, and substantially non-porous paper or cardboard. In particular, in Figure 2 In the embodiment shown in , the aerosol-cooling element 134 is provided in the form of a rolled and gathered sheet of polylactic acid (PLA). The aerosol-cooling element 134 has a length of approximately 8 mm and an outer diameter of approximately 7.25 mm.

[0420] and Figure 1 Similar to the embodiment, Figure 2The aerosol-generating article 110 includes an upstream section 16 including an upstream element 48 positioned immediately upstream of the strip 12 of aerosol-generating substrate, the upstream element 48 being longitudinally aligned with the strip 12. The upstream element 48 includes a material segment 50 in the form of a cylindrical rod of cellulose acetate and a first wrapper 52 defining the material segment 50. The material segment 50 has a length of approximately 5 mm. The RTD of the material segment 50 is approximately 30 mm H2O.

[0421] The aerosol-generating article 10 further comprises a composite wrapper 54 that attaches the upstream element 48 to the remaining components of the aerosol-generating article. Figure 1 In the embodiment of FIG. 5 , a single combination package 54 is depicted that defines the upstream element 48 , the strip 12 , and the downstream section 14 and holds them together to form the aerosol-generating article.

[0422] The first wrapper 52 comprises a flame retardant composition at a location along the material section 50. In more detail, the first wrapper 52 is formed from a packaging base material having a flame retardant coating applied on a surface of the packaging base material facing away from the material section 50.

[0423] In more detail, the flame retardant coating is provided in at least the treated portion of the first wrapper 52 extending between the proximal end and the distal end of the material segment 50. The treated portion contains about 15 grams of the flame retardant compound per square meter of the treated portion surface area. Thus, the treated portion of the wrapper 52 has an overall basis weight that is greater than the basis weight of the base material of the wrapper. Figure 2 In the embodiment of , the treated portion has a length that substantially matches the length of the material segment 50 and extends over substantially the entire outer surface area of ​​the material segment 50 .

[0424] In addition, Figure 2 In the embodiment of the present invention, the combination wrapper 54 defining the upstream element 48 and attaching the upstream element 48 to the rest of the aerosol-generating article further comprises a flame retardant at a location along the material segment 50 of the upstream element 48. In more detail, the combination wrapper 54 is formed from a packaging base material having a flame retardant coating applied on a surface of the packaging base material facing away from the material segment 50.

[0425] For the purpose of this specification and the appended claims, unless otherwise indicated, all numbers representing amounts, quantities, percentages, etc. should be understood to be modified by the term "about" in all cases. Moreover, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein that may be specifically listed or may not be listed in this article. Therefore, in this context, the number A is understood to be 5% of A±A. In this context, the number A can be regarded as including the numerical value within the general standard error for the measurement of the attribute modified by the number A. In some cases used in the appended claims, the number A can deviate from the percentages listed above, provided that the amount of A deviation does not substantially affect the basic characteristics and novel features of the invention claimed. Moreover, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein that may be specifically listed or may not be listed in this article.

Claims

1. An aerosol-generating article, comprising: an aerosol-generating element comprising a strip of aerosol-generating substrate defined by a stick pack; an upstream element positioned upstream of the aerosol-generating element, wherein the upstream element comprises a segment of material defined by a first wrapper; as well as a second wrapper, said second wrapper confining both the upstream element and the aerosol-generating element; wherein the first wrapper or the second wrapper or both comprise a flame retardant composition comprising one or more flame retardant compounds at a location along the material segment of the upstream element.

2. An aerosol-generating article according to claim 1, wherein the first package comprises a packaging base material and the flame retardant composition is arranged on a surface of the material segment of the packaging base material facing the upstream element, a surface of the material segment of the packaging base material facing away from the upstream element, or both.

3. An aerosol-generating article according to claim 1 or 2, wherein the second packaging comprises a packaging base material, and the flame retardant composition is arranged on a surface of the material segment of the packaging base material facing the upstream element, a surface of the material segment of the packaging base material facing away from the upstream element, or both.

4. An aerosol-generating article according to any one of claims 1 to 3, wherein the flame retardant composition comprises a polymer and a mixed salt based on at least one monocarboxylic acid, dicarboxylic acid and / or tricarboxylic acid, at least one polyphosphoric acid, pyrophosphoric acid and / or phosphoric acid, and a hydroxide or salt of an alkali metal or alkaline earth metal, wherein the at least one monocarboxylic acid, dicarboxylic acid and / or tricarboxylic acid forms a carboxylate with the hydroxide or salt, and the at least one polyphosphoric acid, pyrophosphoric acid and / or phosphoric acid forms a phosphate with the hydroxide or salt.

5. An aerosol-generating article according to any one of claims 1 to 3, wherein the flame retardant composition comprises at least one C 10 Or higher fatty acids, tall oil fatty acids (TOFA), phosphorylated linseed oil, phosphorylated downstream corn oil modified cellulose.

6. An aerosol-generating article according to any one of claims 2 to 5, wherein the flame retardant composition is applied as a coating on at least one side of the packaging base material of the package by a size press, spraying, printing or coating based application process.

7. An aerosol-generating article according to any preceding claim, wherein the segment of material comprises a rod of cellulose acetate.

8. An aerosol-generating article according to any preceding claim, wherein the segment of material comprises a hollow tubular body.

9. An aerosol-generating article according to any preceding claim, wherein the section of material comprises a rolled sheet defining a plurality of longitudinally extending channels.

10. An aerosol-generating article according to any preceding claim, wherein the aerosol-generating substrate comprises at least 10% by weight of an aerosol-former.

11. An aerosol-generating article according to any one of claims 1 to 10, wherein the aerosol-generating substrate comprises a plurality of shreds of tobacco material.

12. An aerosol-generating article according to any one of claims 1 to 10, wherein the aerosol-generating substrate comprises one or more sheets of homogenised tobacco material.

13. The aerosol-generating article according to any one of claims 1 to 10, wherein the aerosol-generating substrate comprises a gel composition comprising nicotine, at least one gelling agent, and an aerosol former.

14. An aerosol-generating article according to any one of claims 1 to 10, wherein the aerosol-generating substrate comprises hydroxypropyl methylcellulose and one or more cellulose-based strengtheners.

15. An aerosol generating system comprising an electrically operated aerosol generating device and an aerosol generating article according to any one of claims 1 to 21, the aerosol generating device comprising means for heating the aerosol generating substrate to a temperature sufficient to generate an aerosol from the aerosol generating substrate.

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