CN115955922A

CN115955922A - Aerosol-generating article comprising a flame retardant

Info

Publication number: CN115955922A
Application number: CN202180034534.4A
Authority: CN
Inventors: S·帕帕基里罗
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2020-05-19
Filing date: 2021-05-18
Publication date: 2023-04-11
Also published as: JP2023525800A; IL298269A; MX2022014476A; BR112022023138A2; US20230337723A1; WO2021233914A1; KR20230011977A; CA3179114A1; AU2021274841A1; EP4152971A1

Abstract

An aerosol-generating article (10. The aerosol-generating article (10: a rod (12) of aerosol-generating substrate; a downstream section (14; and a wrapper (70) defining at least a rod (12) of aerosol-generating substrate. The aerosol-generating substrate has a density of greater than about 300 mg/cc and the wrapper (70) comprises a flame retardant composition comprising one or more flame retardant compounds.

Description

Aerosol-generating article comprising a flame retardant

Technical Field

The present invention relates to an aerosol-generating article comprising an aerosol-generating substrate and adapted to produce an inhalable aerosol upon heating.

Background

Aerosol-generating articles in which an aerosol-generating substrate, such as a tobacco-containing substrate, is heated rather than combusted are known in the art.

In a conventional cigarette, a consumer applies a flame to the distal end of the cigarette while drawing air through the proximal end. The heat generated locally by the flame and the oxygen in the air drawn through the cigarette causes the distal end of the cigarette to be lit and the combustion of the tobacco rod and surrounding wrapper generates the breathable smoke. In contrast, in heated aerosol-generating articles, aerosols are generated by more gentle transfer of heat from a heat source to a physically separate aerosol-generating substrate or material, which may be positioned in contact with, inside, 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 entrained in air drawn through the aerosol-generating article. As the released compound cools, the compound condenses to form an aerosol.

A number of prior art documents disclose aerosol-generating devices for consuming aerosol-generating articles. Such devices include, for example, electrically heated aerosol-generating devices in which an aerosol is generated by transferring heat from one or more electric heater elements of the aerosol-generating device to an aerosol-generating substrate of a heated aerosol-generating article. For example, electrically heated aerosol-generating devices have been proposed which comprise an internal heating blade adapted to be inserted into an aerosol-generating substrate. As an alternative, inductively heatable aerosol-generating articles have been proposed which comprise an aerosol-generating substrate and a susceptor arranged within the aerosol-generating substrate.

Aerosol-generating articles in which a tobacco-containing substrate is heated without combustion present a number of challenges not encountered with conventional smoking articles. The tobacco-containing substrate is typically heated to a significantly lower temperature than the temperature reached by the combustion front in a conventional cigarette. However, the heating temperature cannot be too low, as this may have an impact on the nicotine release from the tobacco containing substrate and the nicotine delivery to the consumer. Furthermore, in order to maximise the heat transfer efficiency, it is generally desirable that the heat source is located as close as possible to the aerosol-generating substrate and preferably in contact with the aerosol-generating substrate.

Thus, in existing aerosol-generating articles designed to be heated by means of a heating sheet inserted into the aerosol-generating substrate or by means of a susceptor arranged within the aerosol-generating substrate, the aerosol-generating substrate is typically defined by a package combining a paper layer and a metal foil, such as an aluminium foil. Thus, the metal layer between the aerosol-generating substrate and the paper wrapper acts as a heat shield and prevents the paper wrapper from charring or charring during use. This is desirable as it will increase the safety of use of the aerosol-generating article and prevent delivery of paper combustion products or paper pyrolysis products to the consumer during use. However, the inclusion of one such metallic shield may make the manufacturing process more complex and costly and may result in increased environmental impact of the aerosol-generating article when disposed of after use. Furthermore, it may be difficult to determine whether an aerosol-generating article has been used effectively, since the original visual effect of the aerosol-generating article remains substantially unchanged during use.

Disclosure of Invention

It is therefore desirable to provide a novel and improved aerosol-generating article which is easier to handle and has reduced environmental impact, whilst being suitable for preventing charring or charring of the article during use. Secondly, it is generally believed that there is a need for a new and improved aerosol-generating article which substantially prevents abuse of the article such that the article can only be correctly used in an aerosol-generating device adapted to heat an aerosol-generating substrate and not as a conventional cigarette. Furthermore, it would be desirable to provide an aerosol-generating article which can be manufactured efficiently and at high speeds, preferably without requiring extensive modification of existing devices.

Accordingly, it would be desirable to provide new and improved aerosol-generating articles adapted to achieve at least one of the above-described desired results.

The present disclosure relates to an aerosol-generating article for generating an inhalable aerosol upon heating, the aerosol-generating article comprising a rod of aerosol-generating substrate. The aerosol-generating substrate may comprise at least one aerosol-former. The aerosol-generating article may comprise a downstream section at a location downstream of the rod of aerosol-generating substrate. The aerosol-generating article may comprise a wrapper defining at least a rod of aerosol-generating substrate. The aerosol-generating substrate may have a density of greater than about 300 mg/cc. The package can comprise a flame retardant composition comprising one or more flame retardant compounds.

According to the present invention there is provided an aerosol-generating article for generating an inhalable aerosol upon heating, the aerosol-generating article comprising: a rod of aerosol-generating substrate; a downstream section at a position downstream of the rod of aerosol-generating substrate; and a wrapper defining at least the rod of aerosol-generating substrate. The aerosol-generating substrate has a density of greater than about 300 mg/cc. Further, the package comprises a flame retardant composition comprising one or more flame retardant compounds.

The present disclosure also relates to a method of manufacturing an aerosol-generating article for generating an inhalable aerosol upon heating. The method may comprise the step of providing a continuous rod of aerosol-generating substrate, wherein the aerosol-generating substrate has a density of greater than about 300 mg/cc. The method may comprise the further step of defining a continuous rod of aerosol-generating substrate with a wrapper comprising the flame retardant composition. The method may include the additional step of cutting the defined continuous strip into discrete strips, each discrete strip defined by a portion of a package containing the flame retardant composition.

According to the present invention there is also provided a method of manufacturing an aerosol-generating article for generating an inhalable aerosol upon heating, the method comprising: providing a continuous rod of aerosol-generating substrate, wherein the aerosol-generating substrate has a density of greater than about 300 mg/cc; defining a continuous rod of aerosol-generating substrate with a wrapper comprising a flame retardant composition; and cutting the defined continuous strip into discrete strips, each discrete strip defined by a portion of the package containing the flame retardant composition.

The present disclosure also relates to an aerosol-generating system comprising an electrically operated aerosol-generating device and an aerosol-generating article as set forth above. The aerosol-generating device may comprise means for heating a rod of aerosol-generating substrate to a temperature sufficient to generate an aerosol from the aerosol-generating substrate.

According to the present invention there is also provided an aerosol-generating system comprising an electrically operated aerosol-generating device comprising means for heating a rod of aerosol-generating substrate to a temperature sufficient to generate an aerosol from the aerosol-generating substrate, and an aerosol-generating article as described above.

As briefly described above, the present invention provides an aerosol-generating article for generating an inhalable aerosol upon heating, wherein the article comprises a rod of aerosol-generating substrate and a downstream section at a position downstream of the rod of aerosol-generating substrate. In more detail, the present invention provides an aerosol-generating article for generating an inhalable aerosol when heated at a temperature of about 100 degrees celsius to about 800 degrees celsius, preferably about 150 degrees celsius to about 500 degrees celsius, more preferably about 200 degrees celsius to about 300 degrees celsius.

These temperatures are significantly lower than those reached in conventional cigarettes when the tobacco-containing substrate is combusted, and even more significantly lower than those reached by commercially available cigarette lighters, which may reach temperatures in the range of about 1000 to 2000 degrees celsius, and even higher.

Furthermore, the aerosol-generating article comprises a wrapper defining the rod of aerosol-generating substrate or both the rod and the downstream section of the aerosol-generating substrate. The aerosol-generating substrate has a density in excess of about 300 mg/cc compared to existing articles, and the package comprises the flame retardant composition.

The present inventors have found that by defining an aerosol-generating substrate with a package comprising a flame retardant composition, i.e. a package comprising one or more flame retardant compounds, it is advantageously possible to prevent charring or charring of the package and the underlying aerosol-generating substrate during use. In other words, combustion and pyrolysis of the components of the aerosol-generating article according to the invention can advantageously be substantially prevented.

In aerosol-generating articles according to the invention, this is ideally achieved without the need to include an additional layer of metal foil or other heat shielding material in the aerosol-generating article. This will simplify the manufacturing process and thus may reduce the manufacturing cost. Disposal of the aerosol-generating article according to the invention is also made easier, since there is no need to separate and recover valuable recyclable material, such as aluminium foil, when discarding the used aerosol-generating article. In addition, the present inventors have found that by defining the aerosol-generating substrate by means of a package as described above, the aerosol-generating article appears to have significantly discoloured when the aerosol-generating substrate has been exposed to a temperature in the range of from about 100 degrees celsius to about 800 degrees celsius during use, the surface of the package turning dark brown or blackish. Thus, the consumer can immediately determine whether the aerosol-generating article has been previously used and should be discarded.

By adjusting the amount of flame retardant compound in the package (e.g., in terms of the amount of treated portion of surface area per square meter), the degree to which the surface of the package is treated with the flame retardant composition, and the formulation of the flame retardant composition (i.e., the nature of the one or more flame retardant compounds), the flame retardant properties of the package and the aerosol-generating article as a whole can be advantageously enhanced.

Accordingly, the present invention provides an improved aerosol-generating article which is capable of substantially preventing charring and charring of the aerosol-generating substrate and package during use. This is because the heat supplied to the article to generate the aerosol can be substantially prevented from causing pyrolysis or combustion of the package base material by providing one or more flame retardant compounds on or within the package or both.

The aerosol-generating article according to the invention is advantageously easy to handle and has reduced environmental impact, as the article does not need to comprise a metal foil layer as is often the case in existing aerosol-generating articles.

Furthermore, the aerosol-generating article according to the invention has the additional benefit that it can only be used correctly as intended, i.e. in combination with a device adapted to heat the aerosol-generating substrate. Indeed, unlike conventional cigarettes, aerosol-generating articles according to the invention are substantially unable to be lit and to sustain combustion as conventional cigarettes.

According to the present invention, there is provided an aerosol-generating article for generating an inhalable aerosol upon heating.

The term "aerosol-generating article" is used herein to refer to an article in which an aerosol-generating substrate is heated to produce an inhalable aerosol for delivery to a consumer. As used herein, the term "aerosol-generating substrate" denotes a substrate capable of releasing volatile compounds upon heating to generate an aerosol.

Traditional smoking is ignited when a user applies a flame to one end of the cigarette and draws air through the other end. The localized heat provided by the flame and the oxygen in the air drawn through the cigarette causes the end of the cigarette to be lit and the resulting combustion produces breathable smoke. In contrast, in heated aerosol-generating articles, an aerosol is generated by heating a flavour-generating substrate, such as tobacco. Known heated aerosol-generating articles include, for example, electrically heated aerosol-generating articles, as well as aerosol-generating articles in which an aerosol is generated by heat transfer from a combustible fuel element or heat source to a physically separate aerosol-forming material. For example, aerosol-generating articles according to the present invention find particular application in aerosol-generating systems comprising an electrically heated aerosol-generating device having an internally heated sheet adapted for insertion into a rod of aerosol-generating substrate. Aerosol-generating articles of this type are described in the prior art (for example in european patent application EP 0822670).

As used herein, the term "aerosol-generating device" refers to a device comprising a heater element which interacts with an aerosol-generating substrate of an aerosol-generating article to generate an aerosol.

As used herein with reference to the present invention, the term "strip" is used to denote a substantially cylindrical element of substantially circular, oval or elliptical cross-section.

As used herein, the term "longitudinal" refers to a direction corresponding to the major longitudinal axis of an aerosol-generating article, which direction extends between an upstream end and a downstream end of the aerosol-generating article. As used herein, the terms "upstream" and "downstream" describe the relative position of an element or portion of an element of an aerosol-generating article with respect to the direction in which an aerosol is conveyed through the aerosol-generating article during use.

During use, air is drawn through the aerosol-generating article in the longitudinal direction. The term "transverse" refers to a direction perpendicular to the longitudinal axis. Any reference to a "cross-section" of an aerosol-generating article or a component of an aerosol-generating article refers to a transverse cross-section, unless otherwise specified.

The term "length" denotes the dimension of a component of an aerosol-generating article in the longitudinal direction. For example, it may be used to denote the dimension of the strip or elongate tubular member in the longitudinal direction.

An aerosol-generating article according to the invention comprises a rod of aerosol-generating substrate. Furthermore, the aerosol-generating article comprises a downstream section at a position downstream of the rod of aerosol-generating substrate.

In an aerosol-generating article according to the invention, at least the rod of aerosol-generating substrate is defined by a wrapper. This means that in an aerosol-generating article according to the invention, the same wrapper defining the rod of aerosol-generating substrate may also define at least part of the downstream section or at least part of an optional additional component of the aerosol-generating article provided at a position upstream of the rod of aerosol-generating substrate, or both.

The aerosol-generating article may have an overall length of from about 35 mm to about 100 mm.

Preferably, the overall length of an aerosol-generating article according to the invention is at least about 38 millimetres. More preferably, the aerosol-generating article according to the present invention has an overall length of at least about 40 mm. Even more preferably, the aerosol-generating article according to the present invention has an overall length of at least about 42 mm.

In some embodiments, the overall length of the aerosol-generating article according to the present invention is preferably less than or equal to 80 mm. More preferably, the aerosol-generating article according to the invention has an overall length of less than or equal to 70 mm. Even more preferably, the overall length of the aerosol-generating article according to the invention is preferably less than or equal to 60 mm. Most preferably, the overall length of the aerosol-generating article according to the invention is preferably less than or equal to 50 millimetres.

In preferred embodiments, the overall length of the aerosol-generating article is from about 38 mm to about 70 mm, more preferably from about 40 mm to about 70 mm, even more preferably from about 42 mm to about 70 mm. In other embodiments, the overall length of the aerosol-generating article is preferably from about 38 to about 60 millimetres, more preferably from about 40 to about 60 millimetres, even more preferably from about 42 to about 60 millimetres. In a further embodiment, the overall length of the aerosol-generating article is preferably from about 38 mm to about 50 mm, more preferably from about 40 mm to about 50 mm, even more preferably from about 42 mm to about 50 mm. In an exemplary embodiment, the overall length of the aerosol-generating article is about 45 millimeters.

In other embodiments, the overall length of the aerosol-generating article according to the invention is preferably at least about 40 mm, more preferably about 50 mm, even more preferably about 60 mm. In these embodiments, the overall length of aerosol generation is preferably less than or equal to about 95 millimeters, more preferably less than or equal to about 90 millimeters, even more preferably less than or equal to about 85 millimeters, and most preferably less than or equal to about 80 millimeters.

In preferred embodiments, the overall length of the aerosol-generating article is from about 40 mm to about 95 mm, preferably from about 40 mm to about 90 mm, more preferably from about 40 mm to about 85 mm, even more preferably from about 40 mm to about 80 mm. In other embodiments, the overall length of the aerosol-generating article is from about 50 mm to about 95 mm, preferably from about 50 mm to about 90 mm, more preferably from about 50 mm to about 85 mm, even more preferably from about 50 mm to about 80 mm. In a further embodiment, the overall length of the aerosol-generating article is from about 60 mm to about 95 mm, preferably from about 60 mm to about 90 mm, more preferably from about 60 mm to about 85 mm, even more preferably from about 60 mm to about 80 mm. In still further embodiments, the overall length of the aerosol-generating article is from about 70 mm to about 95 mm, preferably from about 70 mm to about 90 mm, more preferably from about 70 mm to about 85 mm, even more preferably from about 70 mm to about 80 mm. In an exemplary embodiment, the overall length of the aerosol-generating article is about 75 millimeters.

Aerosol-generating articles according to the present invention may have an outer diameter of at least 4 millimetres. Preferably, the aerosol-generating article has an outer diameter of at least 5 millimetres. More preferably, the aerosol-generating article has an outer diameter of at least 6 millimetres. Even more preferably, the aerosol-generating article has an outer diameter of at least 7 millimetres.

Preferably, the aerosol-generating article has an outer diameter of less than or equal to about 12 millimetres. More preferably, the aerosol-generating article has an outer diameter of less than or equal to about 10 millimetres. Even more preferably, the aerosol-generating article has an outer diameter of less than or equal to about 8 millimetres.

In some embodiments, the aerosol-generating article has an outer diameter of from about 4 mm to about 12 mm, preferably from about 5 mm to about 12 mm, more preferably from about 6 mm to about 12 mm, even more preferably from about 7 mm to about 12 mm. In other embodiments, the aerosol-generating article has an outer diameter of from about 4 mm to about 10 mm, preferably from about 5 mm to about 10 mm, more preferably from about 6 mm to about 10 mm, even more preferably from about 7 mm to about 10 mm. In a further embodiment, the aerosol-generating article has an outer diameter of from about 4 mm to about 8 mm, preferably from about 5 mm to about 8 mm, more preferably from about 6 mm to about 8 mm, even more preferably from about 7 mm to about 8 mm.

The rod of aerosol-generating substrate may have a length of between about 5 millimetres to about 100 mm.

In some embodiments, the rod of aerosol-generating substrate preferably has a length of at least about 6 millimetres, more preferably at least about 7 millimetres. In these embodiments, the rod of aerosol-generating substrate may have a length of less than about 90 mm and preferably has a length of less than about 70 mm, more preferably less than about 65 mm, more preferably less than about 50 mm, most preferably less than 40 mm. In a particularly preferred embodiment, the rod of aerosol-generating substrate has a length of less than about 35 mm, more preferably less than 25 mm, even more preferably less than about 20 mm. In one embodiment, the rod of aerosol-generating substrate may have a length of about 10 millimetres. In a preferred embodiment, the rod of aerosol-generating substrate has a length of about 12 mm. This may be combined with an overall length of the aerosol-generating article of about 45 mm.

In other embodiments, the aerosol-generating rod preferably has a length of at least about 10 mm, more preferably at least about 20 mm, even more preferably at least about 30 mm. In these embodiments, the length of the rod of aerosol-generating substrate is preferably less than or equal to about 60 millimetres, more preferably less than or equal to about 50 millimetres, even more preferably less than or equal to about 40 millimetres.

In a preferred embodiment, the rod of aerosol-generating substrate has a length of from about 10 mm to about 60 mm, preferably from about 20 mm to about 60 mm, more preferably from about 30 mm to about 60 mm. In other embodiments, the rod of aerosol-generating substrate has a length of from about 10 mm to about 50 mm, preferably from about 20 mm to about 50 mm, more preferably from about 30 mm to about 50 mm. In a further embodiment, the rod of aerosol-generating substrate has a length of from about 10 mm to about 40 mm, preferably from about 20 mm to about 40 mm, more preferably from about 40 mm to about 60 mm. In an exemplary embodiment, the rod of aerosol-generating substrate is about 35 millimetres in length. This may be combined with an overall length of the aerosol-generating article of about 75 mm.

Preferably, the rod of aerosol-generating substrate has a substantially uniform cross-section along the length of the rod. It is particularly preferred that the rod of aerosol-generating substrate has a substantially circular cross-section.

According to the invention, the aerosol-generating substrate has a density of greater than about 300 mg/cc. As used herein, with respect to the aerosol-generating substrate of the aerosol-generating article according to the present invention, the term "density" refers to the "apparent density" or "bulk density" of the substrate and is equal to the total mass of the body of a given volume of aerosol-generating substrate (which is the mass of homogenized plant material, aerosol former, etc. or the mass of a given volume of gel composition) divided by said given volume of the rod of aerosol-generating substrate.

Thus, for example, the density of the aerosol-generating substrate determines the mass of the body of homogenized tobacco material of a given volume and the filling efficiency for a given surface area of the homogenized tobacco material. The density of homogenized tobacco material is generally determined to a large extent by the type of process used for its manufacture. Several remanufacturing processes for producing homogenized tobacco material are known in the art. These processes include, but are not limited to: se:Sup>A papermaking process of the type described in, for example, US-se:Sup>A-5,724,998; casting processes of the type described, for example, in US-se:Sup>A-5,724,998; se:Sup>A dough Reconfiguration (DOUGH Reconfiguration) process of the type described, for example, in US-A-3,894,544; and extrusion processes of the type described in, for example, GB-A-983,928.

Typically, the density of the homogenized tobacco material produced by the extrusion process and the dough reconstitution process is greater than the density of the homogenized tobacco material produced by the casting process. The density of the homogenized tobacco material produced by the extrusion process may be greater than the density of the homogenized tobacco material produced by the dough reconstitution process.

For example, the density of the aerosol-generating substrate is at least about 310 mg/cc or at least about 320 mg/cc or at least about 330 mg/cc.

In some embodiments, the density of the aerosol-generating substrate is preferably at least about 350 mg/cc. More preferably, the aerosol-generating substrate has a density of at least about 400 mg/cc. Even more preferably, the aerosol-generating substrate has a density of at least about 450 mg/cc. In a particularly preferred embodiment, the aerosol-generating substrate has a density of at least about 500 mg/cc. Preferably, the density of the aerosol-generating substrate is less than or equal to about 1000 mg/cc, more preferably less than or equal to about 900 mg/cc, even more preferably less than or equal to about 800 mg/cc. For example, the aerosol-generating substrate may have a density of from about 350 mg/cc to about 1000 mg/cc, preferably from about 400 mg/cc to about 1000 mg/cc, more preferably from about 450 mg/cc to about 1000 mg/cc, even more preferably from about 500 mg/cc to about 1000 mg/cc. As another example, the aerosol-generating substrate may have a density of from about 350 mg/cc to about 900 mg/cc, preferably from about 400 mg/cc to about 900 mg/cc, more preferably from about 450 mg/cc to about 900 mg/cc, even more preferably from about 500 mg/cc to about 900 mg/cc. As yet another example, the aerosol-generating substrate may have a density of from about 350 mg/cc to about 800 mg/cc, preferably from about 400 mg/cc to about 800 mg/cc, more preferably from about 450 mg/cc to about 800 mg/cc, even more preferably from about 500 mg/cc to about 800 mg/cc.

In other embodiments, the aerosol-generating substrate has a density of at least about 600 mg/cc, preferably at least about 700 mg/cc, more preferably at least about 800 mg/cc, even more preferably at least about 900 mg/cc. In some particularly preferred embodiments, the aerosol-generating substrate has a density of at least about 1 g/cc, preferably at least about 1.1 g/cc, more preferably at least about 1.2 g/cc, even more preferably at least about 1.3 g/cc. Preferably, the aerosol-generating substrate has a density of less than or equal to about 2.0 grams per cubic centimeter, more preferably less than or equal to about 1.9 grams per cubic centimeter, and even more preferably less than or equal to 1.8 grams per cubic centimeter. In preferred embodiments, the aerosol-generating substrate has a density of less than or equal to about 1.7 grams per cubic centimeter, more preferably less than or equal to about 1.6 grams per cubic centimeter, and even more preferably less than or equal to about 1.5 grams per cubic centimeter.

As an example, the aerosol-generating substrate has a density of from about 1 g/cc to about 1.7 g/cc, preferably from about 1.1 g/cc to about 1.7 g/cc, more preferably from about 1.2 g/cc to about 1.7 g/cc, even more preferably from about 1.3 g/cc to about 1.7 g/cc. As another example, the aerosol-generating substrate has a density of from about 1 g/cc to about 1.6 g/cc, preferably from about 1.1 g/cc to about 1.6 g/cc, more preferably from about 1.2 g/cc to about 1.6 g/cc, and even more preferably from about 1.3 g/cc to about 1.6 g/cc. As yet another example, the aerosol-generating substrate has a density of from about 1 g/cc to about 1.5 g/cc, preferably from about 1.1 g/cc to about 1.5 g/cc, more preferably from about 1.2 g/cc to about 1.5 g/cc, even more preferably from about 1.3 g/cc to about 1.5 g/cc.

The aerosol-generating substrate may be a solid aerosol-generating substrate.

In certain preferred embodiments, the aerosol-generating substrate comprises a homogenized plant material, preferably a homogenized tobacco material.

As used herein, the term "homogenized plant material" encompasses any plant material formed from agglomeration of plant particles. For example, a sheet or web of homogenized tobacco material for use in the aerosol-generating substrate of the invention may be formed by agglomerating particles of tobacco material obtained by comminuting, grinding or grinding a plant material and optionally one or more of a tobacco leaf body and a tobacco leaf stem. Homogenized plant material may be produced by casting, extrusion, paper making processes, or any other suitable process known in the art.

The homogenized plant material may be provided in any suitable form. For example, the homogenized plant material may be in the form of one or more sheets. As used herein with reference to the present invention, the term "sheet" describes a layered element having a width and length substantially greater than its thickness.

Alternatively or additionally, the homogenized plant material may be in the form of a plurality of pellets or granules.

Alternatively or additionally, the homogenized plant material may be in the form of a plurality of strips, strips or pieces. As used herein, the term "sliver" describes an elongated member material having a length that is substantially greater than its width and thickness. The term "strand" should be considered to include strips, pieces and any other homogenized plant material having a similar form. The strands of homogenized plant material may be formed from sheets of homogenized plant material, for example by cutting or shredding, or by other methods, for example by extrusion methods.

In some embodiments, the thin strands may be formed in situ within the aerosol-generating substrate as a result of splitting or splitting of the sheet of homogenised plant material during formation of the aerosol-generating substrate, for example as a result of curling. The homogenized plant material strands within the aerosol-generating substrate may be separated from each other. Alternatively, each strand of homogenized plant material within the aerosol-generating substrate may be at least partially connected to an adjacent strand or strands along the length of the strand. For example, adjacent strands may be connected by one or more fibers. This may occur where a thin line is formed, for example due to splitting of a sheet of homogenised plant material during production of the aerosol-generating substrate, as described above.

Preferably, the aerosol-generating substrate is in the form of one or more sheets of homogenised plant material. In various embodiments of the invention, one or more sheets of homogenized plant material may be produced by a casting process. In various embodiments of the invention, one or more sheets of homogenized plant material may be produced by a papermaking process. One or more sheets as described herein may each individually have a thickness of between 100 and 600 microns, preferably between 150 and 300 microns, and most preferably between 200 and 250 microns. Individual thickness refers to the thickness of the individual sheets, while combined thickness refers to the total thickness of all sheets that make up the aerosol-generating substrate. For example, if the aerosol-generating substrate is formed from two separate sheets, the combined thickness is the sum of the thicknesses of the two separate sheets or, in the case of two sheets stacked in the aerosol-generating substrate, the measured thicknesses of the two sheets.

One or more sheets as described herein may each individually have about 100g/m ² To about 300g/m ² Grammage of (d).

As described in one or more of this documentThe plurality of sheets can each individually have about 0.3g/cm ³ To about 1.3g/cm ³ Preferably about 0.7g/cm ³ To about 1.0g/cm ³ The density of (c).

In embodiments of the invention wherein the aerosol-generating substrate comprises one or more sheets of homogenized plant material, said sheets are preferably in the form of one or more aggregated sheets. As used herein, the term "gathered" means that the sheet of homogenized plant material is rolled, folded or otherwise compressed or shrunk to be substantially transverse to the cylindrical axis of the rod or strip.

One or more sheets of homogenized plant material may be gathered transversely with respect to their longitudinal axis and defined with a wrapper to form a continuous strip or rod.

One or more sheets of homogenized plant material may advantageously be curled or similarly treated. As used herein, the term "crimped" means that the sheet has a plurality of substantially parallel ridges or corrugations. Alternatively or in addition to crimping, one or more sheets of homogenized plant material may be embossed, debossed, perforated or otherwise deformed to provide texture on one or both sides of the sheet.

Preferably, each sheet of homogenized plant material may be crimped such that it has a plurality of ridges or corrugations substantially parallel to the cylindrical axis of the rod. This treatment advantageously promotes the aggregation of the curled sheet of homogenised plant material to form the rod. Preferably, one or more sheets of homogenized plant material may be gathered. It is understood that the curled sheet of homogenized plant material may alternatively or additionally have a plurality of substantially parallel ridges or corrugations disposed at an acute or obtuse angle to the cylindrical axis of the rod. The sheet may be curled to such an extent that the integrity of the sheet is disrupted at a plurality of parallel ridges or corrugations, causing the material to separate and resulting in the formation of fragments, slivers or strips of homogenised plant material.

Alternatively, one or more sheets of homogenized plant material may be cut into thin strips as described above. In such embodiments, the aerosol-generating substrate comprises a plurality of homogenized plant material strands. The strands may be used to form rods. Typically, the width of these strands is about 5 mm, or about 4 mm, or about 3 mm, or about 2 mm or less. The length of the strands may be greater than about 5 millimeters, between about 5 millimeters and about 15 millimeters, about 8 millimeters to about 12 millimeters, or about 12 millimeters. Preferably, the slivers have substantially the same length as each other. The length of the sliver may be determined by the manufacturing process, whereby the sliver is cut into shorter rods and the length of the sliver corresponds to the length of the rod. The strands may be brittle, which may lead to breakage, especially during transport. In this case, the length of some of the strands may be less than the length of the rod.

The plurality of filaments preferably extends substantially longitudinally along the length of the aerosol-generating substrate in alignment with the longitudinal axis. Preferably, the plurality of strips are thus aligned substantially parallel to each other.

The homogenized plant material may comprise up to about 95 weight percent plant particles on a dry weight basis. Preferably, the homogenized plant material comprises at most about 90 weight percent plant particles, more preferably at most about 80 weight percent plant particles, more preferably at most about 70 weight percent plant particles, more preferably at most about 60 weight percent plant particles, more preferably at most about 50 weight percent plant particles on a dry weight basis.

For example, the homogenized plant material may comprise between about 2.5% and about 95% by weight plant particles, or between about 5% and about 90% by weight plant particles, or between about 10% and about 80% by weight plant particles, or between about 15% and about 70% by weight plant particles, or between about 20% and about 60% by weight plant particles, or between about 30% and about 50% by weight plant particles on a dry weight basis.

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

With reference to the present invention, the term "tobacco particles" describes particles of any plant member of the nicotiana genus. The term "tobacco particles" includes ground or comminuted tobacco lamina, ground or comminuted tobacco leaf stems, tobacco dust, tobacco fines and other particulate tobacco by-products formed during the processing, handling and transportation of tobacco. In a preferred embodiment, the tobacco particles are derived substantially entirely from tobacco lamina. In contrast, isolated nicotine and nicotine salts are tobacco-derived compounds, but are not considered tobacco particles for the purposes of the present invention and are not included in the percentage of particulate plant material.

The tobacco particles can be prepared from one or more tobacco plants. Any type of tobacco can be used in the blend. Examples of types of tobacco that can be used include, but are not limited to, sun cured, flue cured, burley, maryland (marylandtobacaco), oriental (Orientaltobacco), virginia (Virginiatobacco), and other specialty tobaccos.

Flue-cured tobacco is a method of curing tobacco, particularly for use with virginia tobacco. During the curing process, heated air is circulated through the densely packed tobacco. During the first phase, the tobacco leaves turn yellow and wither. During the second phase, the leaves of the leaf are completely dried. In the third stage, the leaf stalks are completely dried.

Burley tobacco plays an important role in many tobacco blends. Burley tobacco has a distinctive flavor and aroma, and also has the ability to absorb large amounts of casing (smoking).

Oriental tobacco is a tobacco with small lamina and high aromatic qualities. However, oriental tobacco has a milder flavor than, for example, burley tobacco. Thus, a relatively small proportion of oriental tobacco is typically used in tobacco blends.

Kasturi, madura and Jatim are all subtypes of sun-cured tobacco that can be used. Preferably, kasturi tobacco and flue-cured tobacco can be used in the mixture to produce tobacco particles. Thus, the tobacco particles in the particulate plant material may comprise a mixture of Kasturi tobacco and flue-cured tobacco.

The tobacco particles can have a nicotine content of at least about 2.5 weight percent on a dry weight basis. More preferably, the tobacco particles may have a nicotine content of at least about 3 wt.%, even more preferably at least about 3.2 wt.%, even more preferably at least about 3.5 wt.%, most preferably at least about 4 wt.% on a dry weight basis.

In certain other embodiments of the present invention, the homogenized botanical material comprises tobacco particles in combination with non-tobacco botanical flavor particles. Preferably, the non-tobacco botanical flavour particle is selected from one or more of the following: ginger granules, eucalyptus granules, clove granules and anise granules. Preferably, in such embodiments, the homogenized botanical material comprises at least about 2.5 weight percent non-tobacco botanical flavor particles on a dry weight basis, with the remainder of the botanical particles being tobacco particles. Preferably, the homogenized botanical material comprises at least about 4% by weight non-tobacco botanical flavor particles on a dry weight basis, more preferably at least about 6% by weight non-tobacco botanical flavor particles, more preferably at least about 8% by weight non-tobacco botanical flavor particles, and more preferably at least about 10% by weight non-tobacco botanical flavor particles. Preferably, the homogenized botanical material comprises up to about 20% by weight of non-tobacco botanical flavor particles, more preferably up to about 18% by weight of non-tobacco botanical flavor particles, more preferably up to about 16% by weight of non-tobacco botanical flavor particles.

The weight ratio of non-tobacco botanical flavour particles to tobacco particles in the particulate botanical material forming the homogenized botanical material may vary depending on the desired flavour characteristics and composition of the aerosol produced by the aerosol-generating substrate during use. Preferably, the homogenized plant material comprises, on a dry weight basis, at least 1.

The homogenized plant material preferably comprises not more than 95 wt.% particulate plant material on a dry weight basis. Thus, the particulate plant material is typically combined with one or more other components to form a homogenized plant material.

The homogenized plant material may also comprise a binder to modify the mechanical properties of the granulated plant material, wherein said binder is comprised in the homogenized plant material during manufacture as described herein. Suitable exogenous binders are known to those skilled in the art and include, but are not limited to: gums such as guar gum, xanthan gum, gum arabic, and locust bean gum; cellulose binders such as hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, and ethyl cellulose; polysaccharides, such as starch; organic acids such as alginic acid; conjugate base salts of organic acids, such as sodium alginate, agar, and pectin; and combinations thereof. Preferably, the binder comprises guar gum.

The binder may be present in an amount of about 1 to about 10 wt. -% based on dry weight of the homogenized plant material, preferably in an amount of about 2 to about 5 wt. -% based on dry weight of the homogenized plant material.

Alternatively or additionally, the homogenized plant material may further comprise one or more lipids to facilitate diffusion of volatile components (e.g. aerosol former, gingerol and nicotine), wherein lipids are included in the homogenized plant material during manufacture as described herein. Suitable lipids for inclusion in the homogenized plant material include, but are not limited to: medium chain triglycerides, cocoa butter, palm oil, palm kernel oil, mango oil, shea butter, soybean oil, cottonseed oil, coconut oil, hydrogenated coconut oil, candelilla wax, carnauba wax, shellac, sunflower wax, sunflower oil, rice bran, and revel a; and combinations thereof.

Alternatively or additionally, the homogenized plant material may further comprise a pH modifier.

Alternatively or additionally, the homogenized plant material may also comprise fibers to modify the mechanical properties of the homogenized plant material, wherein said fibers are included in the homogenized plant material during manufacturing as described herein. Suitable exogenous fibers for inclusion in the homogenized plant material are known in the art and include fibers formed from non-tobacco and non-ginger materials, including but not limited to: cellulose fibers; softwood fibers; hardwood fibers; jute fibers and combinations thereof. Exogenous fibers derived from tobacco and/or ginger may also be added. Any fibres added to the homogenized plant material are not considered to form part of the "particulate plant material" as defined above. Prior to inclusion in the homogenized plant material, the fibers may be treated by suitable processes known in the art, including but not limited to: mechanically pulping; refining; chemical pulping; bleaching; sulfate pulping; and combinations thereof. The fibers typically have a length greater than their width.

Suitable fibers typically have a length greater than 400 microns and less than or equal to 4 millimeters, preferably in the range of 0.7 millimeters to 4 millimeters. Preferably, the fibers are present in an amount of about 2 wt.% to about 15 wt.%, most preferably about 4 wt.%, based on the dry weight of the matrix.

Alternatively or additionally, the homogenized plant material may further comprise one or more aerosol formers. Upon volatilisation, the aerosol former may deliver other vapourising compounds, such as nicotine and flavourings, in the aerosol which are released from the aerosol-generating substrate upon heating. Suitable aerosol-forming agents for inclusion in the homogenized plant material are known in the art and include, but are not limited to: polyols such as triethylene glycol, 1,3-butanediol and glycerol; esters of polyhydric alcohols, such as glycerol mono-, di-or triacetate; and fatty acid esters of mono-, di-or polycarboxylic acids, such as dimethyldodecanedioate and dimethyltetradecanedioate.

The homogenized plant material may have an aerosol former content of between about 5 wt.% and about 30 wt.% on a dry weight basis, for example between about 10 wt.% and about 25 wt.% on a dry weight basis, or between about 15 wt.% and about 20 wt.% on a dry weight basis.

For example, if the substrate is intended for use in an aerosol-generating article of an electrically operated aerosol-generating system having a heating element, it may preferably comprise between about 5 wt% and about 30 wt% aerosol former content on a dry weight basis. If the substrate is intended for use in an aerosol-generating article of an electrically operated aerosol-generating system having a heating element, the aerosol former is preferably glycerol.

In other embodiments, the homogenized plant material may have an aerosol former content of from about 1 wt.% to about 5 wt.% on a dry weight basis. For example, if the substrate is intended for an aerosol-generating article in which the aerosol former is held in a reservoir separate from the substrate, the substrate may have an aerosol former content of greater than 1% and less than about 5%. In such embodiments, the aerosol-former volatilises on heating and the flow of aerosol-former contacts the aerosol-generating substrate so as to entrain flavour from the aerosol-generating substrate in the aerosol.

In other embodiments, the homogenized plant material may have an aerosol former content of about 30% to about 45% by weight. Such relatively high levels of aerosol former are particularly suitable for aerosol-generating substrates which are intended to be heated at temperatures below 275 degrees celsius. In such embodiments, the homogenized plant material preferably further comprises between about 2 weight percent and about 10 weight percent cellulose ether on a dry weight basis and between about 5 weight percent and about 50 weight percent additional cellulose on a dry weight basis. It has been found that the use of a combination of a cellulose ether and an additional cellulose provides particularly effective aerosol delivery when used in aerosol-generating substrates having an aerosol former content of between 30% and 45% by weight.

Suitable cellulose ethers include, but are not limited to, methyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, ethyl hydroxyethyl cellulose, and carboxymethyl cellulose (CMC). In a particularly preferred embodiment, the cellulose ether is carboxymethyl cellulose.

As used herein, the term "additional cellulose" encompasses any cellulosic material incorporated into the homogenized plant material that is not derived from non-tobacco plant particles or tobacco particles provided in the homogenized plant material. Thus, in addition to the non-tobacco plant material or tobacco material, additional cellulose is incorporated into the homogenized plant material as a separate and distinct cellulose source from any cellulose inherently provided within the non-tobacco plant particles or tobacco particles. The additional cellulose is typically derived from a plant other than the non-tobacco plant particles or tobacco particles. Preferably, the additional cellulose is in the form of an inert cellulosic material which is sensorially inert and therefore does not substantially affect the sensory properties of the aerosol generated by the aerosol-generating substrate. For example, the additional cellulose is preferably a tasteless and odorless material.

The additional cellulose may include cellulose powder, cellulose fibers, or a combination thereof.

The aerosol-forming agent may act as a humectant in the aerosol-generating substrate.

In certain preferred embodiments of the present invention, the aerosol-generating substrate comprises a gel composition comprising an alkaloid compound. In a particularly preferred embodiment, the aerosol-generating substrate comprises a gel composition comprising nicotine.

Preferably, the gel composition comprises an alkaloid compound; an aerosol former; and at least one gelling agent. Preferably, the at least one gelling agent forms a solid medium and the glycerol is dispersed in the solid medium, wherein the alkaloid is dispersed in the glycerol. Preferably, the gel composition is a stable gel phase.

Advantageously, the stable gel composition comprising nicotine provides a predictable composition form upon storage or shipment from the manufacturer to the consumer. The stable gel composition comprising nicotine substantially retains its shape. The stable gel composition comprising nicotine releases substantially no liquid phase upon storage or shipment from the manufacturer to the consumer. A stable gel composition comprising nicotine may provide a simple consumable design. The consumable may not necessarily be designed to contain a liquid, and therefore a wider range of materials and container configurations may be considered.

The gel compositions described herein may be combined with an aerosol-generating device to provide nicotine aerosol to the lungs at an inhalation rate or air flow rate in a range of inhalation rates or air flow rates for conventional smoking regimes. The aerosol-generating device may heat the gel composition continuously. The consumer may take multiple inhalations or "puffs," where each "puff" delivers an amount of nicotine aerosol. The gel composition is capable of delivering a high nicotine/low Total Particulate Matter (TPM) aerosol to a consumer when heated, preferably in a continuous manner.

The phrase "stable gel phase" or "stable gel" refers to a gel that substantially retains its shape and quality when exposed to various environmental conditions. The stable gel may not substantially release (sweat) or absorb moisture when exposed to standard temperature and pressure while the relative humidity changes from about 10% to about 60%. For example, a stable gel may substantially retain its shape and quality when exposed to standard temperature and pressure while varying the relative humidity from about 10% to about 60%.

The gel composition includes an alkaloid compound. The gel composition may include one or more alkaloids.

The term "alkaloid compound" refers to any of a class of naturally occurring organic compounds that contain one or more basic nitrogen atoms. Typically, alkaloids contain at least one nitrogen atom in the amine-type structure. This or another nitrogen atom in the molecule of the alkaloid compound may be used as a base in an acid-base reaction. Most alkaloid compounds have one or more of the nitrogen atoms as part of a ring system, such as a heterocycle. In nature, alkaloid compounds are found primarily in plants, and are particularly common in certain flowering plant families. However, some alkaloid compounds are present in animal species and fungi. In the present disclosure, the term "alkaloid compound" refers to alkaloid compounds of natural origin and synthetically produced alkaloid compounds.

The gel composition may preferably comprise an alkaloid compound selected from nicotine, anacitabine, and combinations thereof.

Preferably, the gel composition comprises nicotine.

The term "nicotine" refers to nicotine and nicotine derivatives such as free base nicotine, nicotine salts and the like.

The gel composition preferably comprises from about 0.5% to about 10% by weight of the alkaloid compound. The gel composition can include about 0.5% to about 5% by weight of the alkaloid compound. Preferably, the gel composition comprises from about 1% to about 3% by weight of the alkaloid compound. The gel composition may preferably comprise from about 1.5% to about 2.5% by weight of the alkaloid compound. The gel composition may preferably comprise about 2% by weight of the alkaloid compound. The alkaloid compound component of the gel formulation may be the most volatile component of the gel formulation. In some aspects, water may be the most volatile component of the gel formulation, and the alkaloid compound component of the gel formulation may be the second most volatile component of the gel formulation. In some aspects, water may be the most volatile component of the gel formulation, and the alkaloid compound component of the gel formulation may be the second most volatile component of the gel formulation.

Preferably, the gel composition comprises nicotine. The nicotine may be added to the composition in free base form or in salt form. The gel composition comprises from about 0.5% to about 10% by weight nicotine, or from about 0.5% to about 5% by weight nicotine. Preferably, the gel composition comprises from about 1% to about 3% by weight nicotine, or from about 1.5% to about 2.5% by weight nicotine, or about 2% by weight nicotine. The nicotine component of the gel formulation may be the most volatile component of the gel formulation. In some aspects, water may be the most volatile component of the gel formulation, and the nicotine component of the gel formulation may be the second most volatile component of the gel formulation.

The gel composition includes an aerosol former. Ideally, the aerosol-former is substantially resistant to thermal degradation at the operating temperature of the associated aerosol-generating device. Suitable aerosol-forming agents include, but are not limited to: polyols such as triethylene glycol, 1,3-butanediol and glycerol; esters of polyhydric alcohols, such as glycerol mono-, di-or triacetate; and aliphatic esters of mono-, di-or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate. The polyol or mixture thereof may be one or more of triethylene glycol, 1,3-butanediol, glycerol (glycerol or propane-1,2,3-triol) or polyethylene glycol. The aerosol former is preferably glycerol.

The gel composition may comprise a majority of the aerosol former. The gel composition may comprise a mixture of water and an aerosol former, wherein the aerosol former forms a major portion (by weight) of the gel composition. The aerosol former may form at least about 50% by weight of the gel composition. The aerosol former may form at least about 60% or at least about 65% or at least about 70% by weight of the gel composition. The aerosol former may form from about 70% to about 80% by weight of the gel composition. The aerosol former may form from about 70% to about 75% by weight of the gel composition.

The gel composition may include a majority of glycerin. The gel composition may comprise a mixture of water and glycerol, wherein the glycerol forms the majority (by weight) of the gel composition. The glycerin may form at least about 50% by weight of the gel composition. The glycerin may form at least about 60% or at least about 65% or at least about 70% by weight of the gel composition. The glycerin may form about 70% to about 80% by weight of the gel composition. The glycerin may form from about 70% to about 75% by weight of the gel composition.

The gel composition preferably includes at least one gelling agent. Preferably, the gel composition includes a total amount of gelling agent in the range of about 0.4% to about 10% by weight. More preferably, the composition includes a gelling agent in the range of about 0.5% to about 8% by weight. More preferably, the composition includes a gelling agent in the range of about 1% to about 6% by weight. More preferably, the composition includes a gelling agent in the range of about 2% to about 4% by weight. More preferably, the composition includes a gelling agent in the range of about 2% to about 3% by weight.

The term "gelling agent" refers to a compound that when added to a mixture of 50 wt% water/50 wt% glycerin in an amount of about 0.3 wt%, homogenously forms a solid medium or support matrix that results in a gel. Gelling agents include, but are not limited to, hydrogen-bond cross-linking gelling agents and ionic cross-linking gelling agents.

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

Biopolymers include, for example, gellan gum (natural, low acyl gellan gum, high acyl gellan gum, preferably low acyl gellan gum), xanthan gum, alginate (alginic acid), agar, guar gum, and the like. The composition may preferably comprise xanthan gum. The composition may include two biopolymers. The composition may include three biopolymers. The composition may comprise substantially equal amounts by weight of the two biopolymers. The composition may comprise substantially equal amounts by weight of the three biopolymers.

Preferably, the gel composition includes at least about 0.2 wt.% of the hydrogen-bonding crosslinking gelling agent. Alternatively or additionally, the gel composition preferably includes at least about 0.2 wt% of the ionically crosslinked gelling agent. Most preferably, the gel composition includes at least about 0.2 wt.% of the hydrogen bonding cross-linking gelling agent and at least about 0.2 wt.% of the ionic cross-linking gelling agent. The gel composition may include from about 0.5 wt% to about 3 wt% of the hydrogen-bonding crosslinking gelling agent and from about 0.5 wt% to about 3 wt% of the ionic crosslinking gelling agent, or from about 1 wt% to about 2 wt% of the hydrogen-bonding crosslinking gelling agent and from about 1 wt% to about 2 wt% of the ionic crosslinking gelling agent. The hydrogen-bond crosslinking gelling agent and the ionic crosslinking gelling agent may be present in the gel composition in substantially equal amounts by weight.

The term "hydrogen-bond crosslinking gelling agent" refers to a gelling agent that forms non-covalent crosslinks or physical crosslinks via hydrogen bonds. Hydrogen bonding is an electrostatic dipole-dipole attraction type between molecules, rather than a covalent bond with a hydrogen atom. It is generated by the attractive force between a hydrogen atom covalently bonded to an electronegative atom (such as N, O or an F atom) and another electronegative atom.

The hydrogen bonding cross-linking gelling agent may comprise one or more of galactomannan, gelatin, agarose or konjac gum or agar. The hydrogen bonding cross-linking gelling agent may preferably comprise agar.

The gel composition preferably includes a hydrogen-bonding crosslinking gelling agent in a range of about 0.3 wt% to about 5 wt%. Preferably, the composition includes a hydrogen-bonding crosslinking gelling agent in a range of about 0.5 wt% to about 3 wt%. Preferably, the composition includes a hydrogen-bonding crosslinking gelling agent in a range of about 1 wt% to about 2 wt%.

The gel composition may include galactomannan in a range of about 0.2 wt% to about 5 wt%. Preferably, the galactomannan may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the galactomannan may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the galactomannan may be in the range of about 1 wt% to about 2 wt%.

The gel composition may include gelatin in a range of about 0.2% to about 5% by weight. Preferably, the gelatin may be in the range of about 0.5% to about 3% by weight. Preferably, the gelatin may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the gelatin may be in the range of about 1% to about 2% by weight.

The gel composition may include agarose in a range of about 0.2 wt% to about 5 wt%. Preferably, the agarose may be in the range of about 0.5% to about 3% by weight. Preferably, the agarose may be in the range of about 0.5% to about 2% by weight. Preferably, the agarose may be in the range of about 1% to about 2% by weight.

The gel composition may include konjac gum in a range of about 0.2 wt% to about 5 wt%. Preferably, konjac gum can be in the range of about 0.5% to about 3% by weight. Preferably, konjac gum can be in the range of about 0.5% to about 2% by weight. Preferably, konjac gum can be in the range of about 1% to about 2% by weight.

The gel composition may include agar in a range of about 0.2% to about 5% by weight. Preferably, the agar may be in the range of about 0.5% to about 3% by weight. Preferably, the agar may be in the range of about 0.5% to about 2% by weight. Preferably, the agar may be in the range of about 1% to about 2% by weight.

The term "ionically crosslinking gelling agent" refers to a gelling agent that forms non-covalent crosslinks or physical crosslinks through ionic bonds. Ionic crosslinking involves the association of polymer chains by non-covalent interactions. Crosslinked polymer networks are formed when multivalent molecules of opposite charge are electrostatically attracted to each other to form a crosslinked polymer network.

The ionically cross-linking gelling agent may comprise a low acyl gellan gum, pectin, kappa carrageenan, iota carrageenan, or alginate. The ionic crosslinking gelling agent may preferably comprise a low acyl gellan gum.

The gel composition may include an ionically crosslinked gelling agent in a range from about 0.3 wt% to about 5 wt%. Preferably, the composition includes an ionically crosslinked gelling agent in a range from about 0.5 wt.% to about 3 wt.%. Preferably, the composition includes an ionically crosslinked gelling agent in a range from about 1 wt.% to about 2 wt.%.

The gel composition may include low acyl gellan gum in a range from about 0.2 wt% to about 5 wt%. Preferably, the low acyl gellan gum may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the low acyl gellan gum may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the low acyl gellan gum may be in the range of about 1 wt% to about 2 wt%.

The gel composition may comprise pectin in a range of about 0.2% to about 5% by weight. Preferably, the pectin may be in the range of about 0.5% to about 3% by weight. Preferably, the pectin may be in the range of about 0.5% to about 2% by weight. Preferably, the pectin may be in the range of about 1% to about 2% by weight.

The gel composition may include kappa-carrageenan in a range of about 0.2 wt% to about 5 wt%. Preferably, the kappa-carrageenan may be in the range of about 0.5% to about 3% by weight. Preferably, the kappa-carrageenan may be in the range of about 0.5% to about 2% by weight. Preferably, the kappa-carrageenan may be in the range of about 1% to about 2% by weight.

The gel composition can include iota carrageenan in a range from about 0.2% to about 5% by weight. Preferably, iota carrageenan can range from about 0.5% to about 3% by weight. Preferably, iota carrageenan can be in the range of about 0.5 wt% to about 2 wt%. Preferably, iota carrageenan can be in the range of about 1% to about 2% by weight.

The gel composition may include alginate in a range of about 0.2% to about 5% by weight. Preferably, the alginate may be in the range of about 0.5% to about 3% by weight. Preferably, the alginate may be in the range of about 0.5% to about 2% by weight. Preferably, the alginate may be in the range of about 1% to about 2% by weight.

The gel composition can include a hydrogen-bond crosslinking gellant and an ionic crosslinking gellant in a ratio of about 3:1 to about 1:3. Preferably, the gel composition can include a hydrogen bond crosslinking gelling agent and an ionic crosslinking gelling agent in a ratio of about 2:1 to about 1:2. Preferably, the gel composition can include a hydrogen bonding crosslinking gelling agent and an ionic crosslinking gelling agent in a ratio of about 1:1.

The gel composition may also include a tackifier. The viscosifying agent in combination with the hydrogen-bonded cross-linking gelling agent and the ionically 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 glycerin.

The term "viscosity increasing agent" refers to a compound that, when added homogeneously in an amount of 0.3% by weight to a mixture of 25 ℃, 50% by weight water/50% by weight glycerol, increases viscosity without causing gel formation, the mixture retaining or retaining fluid. Preferably, the tackifier means 0.1s when added homogeneously in an amount of 0.3 wt.% to a mixture of 50 wt.% water/50 wt.% glycerin at 25 ℃ ^-1 The shear rate of (a) increases the viscosity to at least 50cPs, preferably at least 200cPs, preferably at least 500cPs, preferably at least 1000cPs, without causing gel formation, the mixture retaining or compounds retaining the fluid. Preferably, the tackifier means 0.1s when added homogeneously in an amount of 0.3 wt.% to a mixture of 50 wt.% water/50 wt.% glycerin at 25 ℃ ^-1 The shear rate of (a) increases the viscosity by at least 2-fold, or at least 5-fold, or at least 10-fold, or at least 100-fold, compared to the viscosity prior to addition, without causing gel formation, the mixture retaining or retaining the fluid compound.

The viscosity values described herein can be measured using a brookfield RVT viscometer at 25 ℃ rotating the disk RV #2 spindle at 6 revolutions per minute (rpm).

The gel composition preferably includes a tackifier in the range of about 0.2 wt% to about 5 wt%. Preferably, the composition includes a tackifier in the range of about 0.5 wt% to about 3 wt%. Preferably, the composition includes a tackifier in the range of about 0.5 wt% to about 2 wt%. Preferably, the composition includes in the range of about 1% to about 2% by weight of the tackifier.

The viscosifying 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 comprise xanthan gum.

The gel composition may include xanthan gum in a range from about 0.2 wt% to about 5 wt%. Preferably, the xanthan gum can be in the range of about 0.5 wt% to about 3 wt%. Preferably, the xanthan gum can be in the range of about 0.5 wt% to about 2 wt%. Preferably, the xanthan gum can be in the range of about 1% to about 2% by weight.

The gel composition may include carboxymethyl cellulose in a range of about 0.2 wt% to about 5 wt%. Preferably, the carboxymethyl cellulose may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the carboxymethyl cellulose may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the carboxymethyl cellulose may be in the range of about 1% to about 2% by weight.

The gel composition may include microcrystalline cellulose in a range of about 0.2 wt% to about 5 wt%. Preferably, the microcrystalline cellulose may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the microcrystalline cellulose may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the microcrystalline cellulose may be in the range of about 1 wt% to about 2 wt%.

The gel composition may include methylcellulose in a range of about 0.2 wt% to about 5 wt%. Preferably, the methylcellulose may be in the range of about 0.5 wt.% to about 3 wt.%. Preferably, the methylcellulose may be in the range of about 0.5 wt.% to about 2 wt.%. Preferably, the methylcellulose may be in the range of about 1 wt.% to about 2 wt.%.

The gel composition may include gum arabic in a range of about 0.2 wt% to about 5 wt%. Preferably, gum arabic may be in the range of about 0.5 wt% to about 3 wt%. Preferably, gum arabic may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the gum arabic may be in the range of about 1 wt% to about 2 wt%.

The gel composition may include guar gum in a range of about 0.2 wt% to about 5 wt%. Preferably, the guar gum may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the guar gum may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the guar gum may be in the range of about 1% to about 2% by weight.

The gel composition may include lambda carrageenan in a range of about 0.2 wt% to about 5 wt%. Preferably, the lambda carrageenan may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the lambda carrageenan may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the lambda carrageenan may be in the range of about 1 wt% to about 2 wt%.

The gel composition may include starch in a range of about 0.2 wt% to about 5 wt%. Preferably, the starch may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the starch may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the starch may be in the range of about 1% to about 2% by weight.

The gel composition may also include a divalent cation. 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 of a composition that includes a gelling agent, such as an ionically crosslinked gelling agent. The ionic effect may aid in gel formation. The divalent cation may be present in the gel composition in a range of about 0.1 wt.% to about 1 wt.% or about 0.5 wt.%.

The gel composition may also include an acid. The acid may comprise a carboxylic acid. The carboxylic acid may comprise a ketone group. Preferably, the carboxylic acid may include a ketone group having less than about 10 carbon atoms, or less than about 6 carbon atoms, or less than about 4 carbon atoms, such as levulinic acid or lactic acid. Preferably, the carboxylic acid has three carbon atoms (such as lactic acid). Lactic acid surprisingly improves the stability of the gel composition even over similar carboxylic acids. The carboxylic acid may aid in gel formation. The carboxylic acid can reduce the variation in the concentration of the alkaloid compound in the gel composition during storage. The carboxylic acid can reduce the variation in nicotine concentration in the gel composition during storage.

The gel composition may include a carboxylic acid in a range of about 0.1 wt% to about 5 wt%. Preferably, the carboxylic acid may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the carboxylic acid may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the carboxylic acid may be in the range of about 1 wt% to about 2 wt%.

The gel composition may include lactic acid in a range of about 0.1 wt% to about 5 wt%. Preferably, the lactic acid may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the lactic acid may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the lactic acid may be in the range of about 1 wt% to about 2 wt%.

The gel composition may include levulinic acid in a range from about 0.1 wt% to about 5 wt%. Preferably, the levulinic acid can be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the levulinic acid can be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the levulinic acid can be in the range of about 1 weight percent to about 2 weight percent.

The gel composition preferably includes some water. When the gel composition includes some water, the gel composition is more stable. Preferably, the gel composition comprises at least about 1 wt.%, or at least about 2 wt.%, or at least about 5 wt.% water. Preferably, the gel composition comprises at least about 10% or at least about 15% by weight water.

Preferably, the gel composition comprises between about 8% and 32% by weight water. Preferably, the gel composition comprises from about 15% to about 25% by weight water. Preferably, the gel composition comprises from about 18% to about 22% by weight water. Preferably, the gel composition comprises about 20% by weight water.

Preferably, the aerosol-generating substrate comprises between about 150mg and about 350mg of the gel composition.

Preferably, the aerosol-generating substrate comprises a porous medium loaded with the gel composition. An advantage of the porous medium loaded with the gel composition is that the gel composition remains within the porous medium, and this may facilitate manufacture, storage or transport of the gel composition. Which can help maintain the desired shape of the gel composition, particularly during manufacture, shipping, or use.

The porous medium can be any suitable porous material capable of holding or retaining the gel composition. Desirably, the porous medium may allow the gel composition to move therein. In particular embodiments, the porous media comprises a natural material, a synthetic or semi-synthetic material, or a combination thereof. In particular embodiments, the porous media comprises a sheet material, foam, or fibers, such as loose fibers; or a combination thereof. In particular embodiments, the porous media comprises a woven, non-woven, or extruded material, or a combination thereof. Preferably, the porous medium comprises cotton, paper, viscose, PLA or cellulose acetate, or a combination thereof. Preferably, the porous medium comprises a sheet material, such as cotton or cellulose acetate. In a particularly preferred embodiment, the porous medium comprises a sheet made of cotton fibers.

The porous media used in the present invention may be crimped or chopped. In a preferred embodiment, the porous media is coiled. In an alternative embodiment, the porous media comprises shredded porous media. The crimping or chopping process can be before or after loading the gel composition.

Crimping the sheet has the benefit of improving the structure to allow passage through the structure. The passage through the curled sheet material helps to load the gel, hold the gel, and also helps to pass fluid through the curled sheet material. Therefore, there is an advantage in using a curled sheet material as the porous medium.

The chopping allows the gel to be easily absorbed at a high surface area to volume ratio of the medium.

In a particular embodiment, the sheet is a composite. Preferably, the sheet material is porous. The sheet material may assist in the manufacture of the tubular element comprising the gel. The sheet material may assist in introducing the active agent into the tubular member comprising the gel. The sheet material may help to stabilize the structure of the tubular element comprising the gel. The sheet may assist in transporting or storing the gel. The use of a sheet material may enable or facilitate the addition of structure to the porous media, for example by crimping the sheet material.

The porous medium may be a wire. The thread may comprise, for example, cotton, paper or acetate. The thread may also carry a gel, as any other porous medium. An advantage of using a thread as the porous medium is that it can help ease manufacturing.

The wires may be loaded with the gel by any known means. The strands may simply be coated with a gel or the strands may be impregnated with a gel. In manufacture, the wire may be impregnated with a gel and stored ready for inclusion in the assembly of the tubular element.

The porous medium loaded with the gel composition is preferably provided within a tubular element forming part of an aerosol-generating article. The term "tubular element" is used to describe a component suitable for an aerosol-generating article. Desirably, the longitudinal length of the tubular member may be longer than the width, but is not required as it may be part of a multi-component article whose longitudinal length is desirably longer than its width. Typically, the tubular element is cylindrical, but this is not essential. For example, the tubular element may have an elliptical, triangular or rectangular-like polygonal or irregular cross-section.

The tubular element preferably comprises a first longitudinal passage. The tubular element is preferably formed by a wrapper defining a first longitudinal passage. The wrapper is preferably a waterproof wrapper. This waterproof property of the package may be achieved by using a waterproof material or by treating the material of the package. This may be achieved by treating one or both sides of the package. Having water repellency will help to maintain structure, stiffness or rigidity. This may also help to prevent leakage of gel or liquid, especially when using a gel of fluid construction.

In some embodiments, the rod of aerosol-generating substrate further comprises a susceptor element disposed within the aerosol-generating substrate. In practice, in some embodiments of aerosol-generating articles according to the invention, the susceptor element, e.g. the elongated susceptor, is arranged substantially at the rod of aerosol-generating substrate such that the susceptor element is in thermal contact with the 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 located within a fluctuating electromagnetic field, eddy currents induced in the susceptor cause heating of the susceptor. When the elongate susceptor is positioned in thermal contact with the aerosol-generating substrate, the aerosol-generating substrate is heated by the susceptor.

Preferably, the susceptor element is in the form of an elongated susceptor. When used in describing a susceptor, the term "elongated" means that the length dimension of the susceptor is greater than, e.g., two times greater than, its width dimension or its thickness dimension.

The elongate susceptor is preferably arranged substantially longitudinally within the strip. This means that the length dimension of the elongated susceptor is arranged substantially parallel to the longitudinal direction of the strip, e.g. within +/-10 degrees of being parallel to the longitudinal direction of the strip. In a preferred embodiment, the elongate susceptor may be located at a radially central position within the strip and extends along the longitudinal axis of the strip.

Preferably, the elongate susceptor extends all the way to the downstream end of the rod of aerosol-generating article. In some embodiments, the susceptor may extend all the way to the upstream end of the rod of aerosol-generating articles. In a particularly preferred embodiment, the susceptor has substantially the same length as the rod of aerosol-generating substrate and extends from an upstream end of the rod to a downstream end of the rod.

The susceptor is preferably in the form of a needle, strip or blade.

The susceptor preferably has a length of about 5 mm to about 15 mm, for example about 6 mm to about 12 mm or about 8 mm to about 10 mm.

The ratio between the length of the susceptor and the overall length of the aerosol-generating article may be from about 0.2 to about 0.35.

In some embodiments, the ratio between the length of the susceptor and the overall length of the aerosol-generating article is at least about 0.22, more preferably at least about 0.24, even more preferably at least about 0.26. The ratio between the length of the susceptor and the overall length of the aerosol-generating article is preferably less than about 0.34, more preferably less than about 0.32, even more preferably less than about 0.3. In other embodiments, the ratio between the length of the susceptor and the overall length of the aerosol-generating article is preferably from about 0.22 to about 0.34, more preferably from about 0.24 to about 0.34, even more preferably from about 0.26 to about 0.34. In a further embodiment, the ratio between the length of the susceptor and the overall length of the aerosol-generating article is preferably from about 0.22 to about 0.32, more preferably from about 0.24 to about 0.32, even more preferably from about 0.26 to about 0.32. In still further embodiments, the ratio between the length of the susceptor and the overall length of the aerosol-generating article is preferably from about 0.22 to about 0.3, more preferably from about 0.24 to about 0.3, even more preferably from about 0.26 to about 0.3.

In a particularly preferred embodiment, the ratio between the length of the susceptor and the overall length of the aerosol-generating article is about 0.27.

The susceptor preferably has a width of about 1 mm to about 5 mm.

The susceptor may generally have a thickness of about 0.01 mm to about 2 mm, such as about 0.5 mm to about 2 mm. In some embodiments, the susceptor preferably has a thickness of from about 10 microns to about 500 microns, more preferably from about 10 microns to about 100 microns.

If the susceptor has a constant cross-section, for example a circular cross-section, it has a preferred width or diameter of about 1 mm to about 5 mm.

If the susceptor has the form of a strip or blade, the strip or blade preferably has a rectangular shape having a width of preferably from about 2 mm to about 8 mm, more preferably from about 3 mm to about 5 mm. For example, a susceptor in the form of a strip or blade may have a width of about 4 millimeters.

If the susceptor is in the form of a strip or blade, the strip or blade preferably has a rectangular shape and a thickness of from about 0.03 mm to about 0.15 mm, more preferably from about 0.05 mm to about 0.09 mm. For example, a susceptor in the form of a strip or blade may have a thickness of about 0.07 millimeters.

In a preferred embodiment, the elongate susceptor is provided in the form of a strip or blade, preferably having a rectangular shape, and having a thickness of from about 55 microns to about 65 microns.

More preferably, the elongate susceptor has a thickness of about 57 microns to about 63 microns. Even more preferably, the elongate susceptor has a thickness of about 58 microns to about 62 microns. In a particularly preferred embodiment, the elongate susceptor has a thickness of about 60 microns.

Without wishing to be bound by theory, the inventors believe that the choice of a given thickness of susceptor as a whole is also influenced by constraints set by the selected length and width of the susceptor and by the geometry and dimensions of the rod of aerosol-generating substrate. For example, the length of the susceptor is preferably selected so as to match the length of the rod of aerosol-generating substrate. Preferably, the width of the susceptor should be chosen such that displacement of the susceptor within the matrix is prevented, while also enabling easy insertion during manufacture.

The inventors have found that in aerosol-generating articles in which a susceptor having a thickness in the above-described range is provided for supplying inductive heating during use, it is advantageously possible to generate and distribute heat throughout the aerosol-generating substrate in a particularly efficient and effective manner. Without wishing to be bound by theory, the inventors believe that this is because one such susceptor is adapted to provide optimal heat generation and heat transfer by means of susceptor surface area and inductive power. In contrast, thinner susceptors may be too easily deformed and may not maintain a desired shape and orientation within a rod of aerosol-generating substrate during manufacture of the aerosol-generating article, which may result in a less uniform and less finely tuned heat distribution during use. At the same time, thicker susceptors may be more difficult to cut to length in an accurate and consistent manner, and this may also affect how accurately longitudinally aligned susceptors are provided within a rod of aerosol-generating substrate, thus also potentially affecting the uniformity of heat distribution within the rod. These advantageous effects are particularly felt when the susceptor extends all the way to the downstream end of the rod of aerosol-generating article. This is thought to be because the Resistance To Draw (RTD) downstream of the susceptor may be substantially minimised because there is no aerosol-generating substrate within the rod at a location downstream of the susceptor that may contribute to RTD. This is particularly effectively achieved in embodiments in which the aerosol-generating article comprises a downstream section comprising a hollow intermediate section. One such hollow intermediate section does not substantially contribute to the overall RTD of the aerosol-generating article and does not directly contact the downstream end of the susceptor.

Without wishing to be bound by theory, the inventors believe that the most downstream portion of the rod of aerosol-generating substrate may act to some extent as a filter for the more upstream portion of the rod of aerosol-generating substrate. Thus, the inventors believe that it is desirable to be able to heat the most downstream portion of the rod of aerosol-generating substrate also uniformly, so that it actively participates in the release of volatile aerosol material and contributes to overall aerosol generation and delivery, and any possible filtering effect, which may hinder the delivery of aerosol to the consumer, will be positively counteracted by the release of volatile aerosol material throughout the aerosol-generating substrate.

Preferably, the elongate susceptor has a length which is the same as or shorter than the length of the aerosol-generating substrate. Preferably, the elongate susceptor has the same length as the aerosol-generating substrate.

The susceptor may be formed from any material capable of being inductively heated to a temperature sufficient to generate an aerosol from the aerosol-generating substrate. Preferred susceptors include metals or carbon.

Preferred susceptors may comprise or consist of ferromagnetic materials, such as ferromagnetic alloys, ferritic iron, or ferromagnetic steel or stainless steel. Suitable susceptors may be or include aluminum. Preferred susceptors may be made from 400 series stainless steel, such as grade 410 or grade 420 or grade 430 stainless steel. Different materials will consume different amounts of energy when positioned within an electromagnetic field having similar frequencies and field strength values.

Thus, parameters of the susceptor, such as material type, length, width, and thickness, may be altered within a known electromagnetic field to provide the desired power consumption. Preferred susceptors may be heated to temperatures in excess of 250 degrees celsius.

Suitable susceptors may include non-metallic cores 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 or glass protective layer, which encapsulates the susceptor. The susceptor may include a protective coating formed of glass, ceramic, or inert metal formed on a core of susceptor material.

The susceptor is arranged in thermal contact with the aerosol-generating substrate. Thus, when the susceptor is heated up, the aerosol-generating substrate is heated and an aerosol is formed. Preferably, the susceptor is arranged in direct physical contact with the aerosol-generating substrate, for example within the aerosol-generating substrate.

The susceptor may be a multi-material susceptor and may include a first susceptor material and a second susceptor material. The first susceptor material is arranged in close physical contact with the second susceptor material. The second susceptor material preferably has a curie temperature below 500 degrees celsius. The first susceptor material is preferably used primarily for heating the susceptor when the susceptor is placed in a fluctuating electromagnetic field. Any suitable material may be used. For example, the first susceptor material may be aluminum, or may be a ferrous material, such as stainless steel. The second susceptor material is preferably used primarily for indicating when the susceptor has reached a certain temperature, which is the curie-temperature of the second susceptor material. The curie temperature of the second susceptor material may be used to regulate the temperature of the entire susceptor during operation. Hence, the curie temperature of the second susceptor material should be below the ignition point of the aerosol-generating substrate. Suitable materials for the second susceptor material may include nickel and certain nickel alloys.

By providing a susceptor having at least a first and a second susceptor material, wherein the second susceptor material has a curie temperature and the first susceptor material does not have a curie temperature, or the first and second susceptor materials have a first and a second curie temperature which are different from each other, the heating of the aerosol-generating substrate and the temperature control of the heating can be separated. The first susceptor material is preferably a magnetic material having a curie temperature above 500 degrees celsius. From a heating efficiency point of view it is desirable that the curie-temperature of the first susceptor material is above any maximum temperature to which the susceptor should be heatable. The second curie temperature may preferably be selected to be below 400 degrees celsius, preferably below 380 degrees celsius, or below 360 degrees celsius. Preferably, the second susceptor material is a magnetic material selected to have a second curie-temperature substantially the same as the desired maximum heating temperature. That is, it is preferred that the second curie temperature is substantially the same as the temperature to which the susceptor should be heated in order to generate an aerosol from the aerosol-generating substrate. The second curie temperature may be, for example, in a range of 200 degrees celsius to 400 degrees celsius, or between 250 degrees celsius and 360 degrees celsius. The second curie temperature of the second susceptor material may, for example, be selected such that the overall average temperature of the aerosol-generating substrate does not exceed 240 degrees celsius after being heated by the susceptor at a temperature equal to the second curie temperature.

As briefly described above, in an aerosol-generating article according to the invention at least the wrapper defining the rod of aerosol-generating substrate comprises a flame retardant composition. In practice, the wrapper defining at least the rod of aerosol-generating substrate comprises a packaging base material and the flame retardant composition is applied on the packaging base material or the packaging base material is impregnated with the flame retardant composition or both.

As used herein, the term "flame retardant composition" refers to a composition comprising one or more flame retardant compounds.

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

The flame retardant composition may also typically comprise 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 serve to facilitate the application of the one or more flame retardant compounds onto or into the package or both.

Some non-flame retardant compounds of the flame retardant composition, such as solvents, are volatile and can evaporate from the package upon drying after the flame retardant composition is applied onto 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 they may only be detectable in trace amounts in the package of the aerosol-generating article according to the invention.

To incorporate the flame retardant composition into paper-based or polymer-based packages, the flame retardant composition may be added to the pulp or polymer mixture during the package manufacturing process, or at a later stage to the package by an application process based on size pressing, spraying, printing, coating, or the like. The flame retardant composition may be applied, for example, as a coating on one side of the wrapper or on both sides of the wrapper.

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

The packaging base material of the wrapper defining at least the rod of aerosol-generating substrate may be a paper packaging base material or a non-paper packaging base material. In a preferred embodiment, the packaging base material of the wrapper defining at least the rod of aerosol-generating substrate comprises paper. Suitable paper packaging base materials for use in particular embodiments of the present invention are known in the art and include, but are not limited to: cigarette paper; and a filter plug segment wrapper. Suitable non-paper packaging base materials for use in particular 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.

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 or at least about 50 grams per square meter. In some embodiments, the packaging base material has a basis weight of at least about 70 grams per square meter.

The packaging base material may have a basis weight of up to about 220 grams per square meter. Preferably, the packaging base material has a basis weight of less than or equal to about 200 grams per square meter. More preferably, the packaging base material has a basis weight of less than or equal to about 180 grams per square meter. Even more preferably, the packaging base material has a basis weight of less than or equal to about 160 grams per square meter.

In preferred embodiments, the packaging base material has a basis weight of less than or equal to about 150 grams per square meter, preferably less than or equal to about 140 grams per square meter, even more preferably less than or equal to about 130 grams per square meter, and most preferably less than or equal to about 120 grams per square meter.

In some embodiments, the packaging base material can have a basis weight of from about 30 grams per square meter to about 220 grams per square meter, preferably from about 40 grams per square meter to about 220 grams per square meter, more preferably from about 50 grams per square meter to about 220 grams per square meter, even more preferably from about 60 grams per square meter to about 220 grams per square meter. In other embodiments, the packaging base material may have a basis weight of from about 30 grams per square meter to about 200 grams per square meter, preferably from about 40 grams per square meter to about 200 grams per square meter, more preferably from about 50 grams per square meter to about 200 grams per square meter, even more preferably from about 60 grams per square meter to about 200 grams per square meter. In further embodiments, the packaging base material may have a basis weight of from about 30 grams per square meter to about 180 grams per square meter, preferably from about 40 grams per square meter to about 180 grams per square meter, more preferably from about 50 grams per square meter to about 180 grams per square meter, even more preferably from about 60 grams per square meter to about 180 grams per square meter. In still other embodiments, the packaging base material can have a basis weight of from about 30 grams per square meter to about 160 grams per square meter, preferably from about 40 grams per square meter to about 160 grams per square meter, more preferably from about 50 grams per square meter to about 160 grams per square meter, even more preferably from about 60 grams per square meter to about 160 grams per square meter.

In particularly preferred embodiments, the packaging base material may have a basis weight of from about 70 grams per square meter to about 110 grams per square meter, more preferably from about 80 grams per square meter to about 110 grams per square meter. In even more preferred embodiments, the packaging base material can have a basis weight of from about 70 grams per square meter to about 100 grams per square meter, even more preferably from about 80 grams per square meter to about 100 grams per square meter.

In other embodiments, the packaging base material may have a basis weight of from about 20 grams per square meter to about 120 grams per square meter, preferably from about 25 grams per square meter to about 120 grams per square meter, more preferably from about 30 grams per square meter to about 120 grams per square meter, even more preferably from about 40 grams per square meter to about 120 grams per square meter, and most preferably from about 50 grams per square meter to about 120 grams per square meter. In further embodiments, the packaging base material may have a basis weight of from about 20 grams per square meter to about 100 grams per square meter, preferably from about 25 grams per square meter to about 100 grams per square meter, more preferably from about 30 grams per square meter to about 100 grams per square meter, even more preferably from about 40 grams per square meter to about 100 grams per square meter, and most preferably from about 50 grams per square meter to about 100 grams per square meter. In still further embodiments, the packaging base material can have a basis weight of from about 20 grams per square meter to about 80 grams per square meter, preferably from about 25 grams per square meter to about 80 grams per square meter, more preferably from about 30 grams to about 80 grams per square meter, even more preferably from about 40 grams per square meter to about 80 grams per square meter, and most preferably from about 50 grams per square meter to about 80 grams per square meter. In alternative embodiments, the packaging base material may have a basis weight of from about 20 grams per square meter to about 70 grams per square meter, preferably from about 25 grams per square meter to about 70 grams per square meter, more preferably from about 30 grams per square meter to about 70 grams per square meter, even more preferably from about 40 grams per square meter to about 70 grams per square meter, and most preferably from about 50 grams per square meter to about 70 grams per square meter.

In other embodiments, the packaging base material may have a basis weight of from about 20 grams per square meter to about 50 grams per square meter, preferably from about 25 grams per square meter to about 50 grams per square meter, more preferably from about 30 grams per square meter to about 50 grams per square meter, even more preferably from about 40 grams per square meter to about 50 grams per square meter.

The wrapper defining at least the rod of aerosol-generating substrate has a total dry basis weight which is the sum of the basis weight of the packaging base material and the weight of the components of the flame retardant composition present on the surface of or within the packaging base material or both. The weight of the flame retardant composition components present on or in the package is the sum of the total weight of the one or more flame retardant compounds and the weight of any remaining non-flame retardant compounds. In the context of the present invention, the weight of the components of the flame retardant composition is also expressed in grams of components per square meter of packaging base material.

The ratio of the total weight of the one or more flame retardant compounds to the total dry basis weight of the package can be considered an indication of the concentration of the one or more flame retardant compounds in the package.

In aerosol-generating articles according to the present invention, the ratio of the total weight of the one or more flame retardant compounds to the total dry basis weight of the package may be at least about 0.02. Preferably, the ratio of the total weight of the one or more flame retardant compounds to the total dry basis weight of the package is at least about 0.03. More preferably, the ratio of the total weight of the one or more flame retardant compounds to the total dry basis weight of the package is at least about 0.04. Even more preferably, the ratio of the total weight of the one or more flame retardant compounds to the total dry basis weight of the package is at least about 0.05.

Preferably, the ratio of the total weight of the one or more flame retardant compounds to the total dry basis weight of the package is less than or equal to about 0.20. More preferably, the ratio of the total weight of the one or more flame retardant compounds to the total dry basis weight of the package is less than or equal to about 0.15. Even more preferably, the ratio of the total weight of the one or more flame retardant compounds to the total dry basis weight of the package is less than or equal to about 0.10.

In some embodiments, the ratio of the total weight of the one or more flame retardant compounds to the total dry basis 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, 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 total dry basis 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, even more preferably from about 0.05 to about 0.15. In a further embodiment, the ratio of the total weight of the one or more flame retardant compounds to the total dry basis 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, even more preferably from about 0.05 to about 0.10.

In the aerosol-generating article according to the invention, the flame retardant composition is provided in the treated portion of the package. This means that the flame retardant composition has been applied on or in the respective part of the packaging base material or has been applied simultaneously on and in the respective part of the packaging base material. Thus, in the treatment section, the wrapper has a total dry basis weight greater than the dry basis weight of the packaging base material.

The treatment portion of the wrapper may extend over at least about 10% of the area of the outer surface of the rod of aerosol-generating substrate defined by the wrapper. Preferably, the treatment portion of the wrapper extends over at least about 20% of the area of the outer surface of the rod of aerosol-generating substrate defined by the wrapper. More preferably, the treated portion of the wrapper extends over at least about 40% of the area of the outer surface of the rod of aerosol-generating substrate. Even more preferably, the treated portion of the wrapper extends over at least about 60% of the area of the outer surface of the rod of aerosol-generating substrate. Most preferably, the treated portion of the wrapper extends over at least about 80% of the area of the outer surface of the rod of aerosol-generating substrate.

In a particularly preferred embodiment, the treated portion of the wrapper extends over at least about 90% of the area of the outer surface of the rod of aerosol-generating substrate. Even more preferably, the treated portion of the wrapper extends over at least about 95% of the area of the outer surface of the rod of aerosol-generating substrate. Most preferably, the treatment portion of the wrapper extends over substantially the entire outer surface area of the rod of aerosol-generating substrate.

The length of the treatment region may be at least about 10% of the length of the rod of aerosol-generating substrate. Preferably, the length of the treatment region is at least about 20% of the length of the rod of aerosol-generating substrate. More preferably, the length of the treatment region is at least about 40% of the length of the rod of aerosol-generating substrate. Even more preferably, the length of the treatment region is at least about 60% of the length of the rod of aerosol-generating substrate. Most preferably, the length of the treatment region is at least about 80% of the length of the rod of aerosol-generating substrate.

In a particularly preferred embodiment, the length of the treatment region is at least about 90% of the length of the rod of aerosol-generating substrate. Even more preferably, the length of the treatment region is at least about 95% of the length of the rod of aerosol-generating substrate. Most preferably, the length of the treatment region is substantially equal to the length of the rod of aerosol-generating substrate.

At least about 10 grams of the flame retardant composition may be applied to the treated portion per square meter of the 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 per square meter of the treated portion surface area.

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.

In some embodiments, from about 10 grams to about 35 grams of the flame retardant composition is applied per square meter of the treated portion surface area. Preferably, from 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, from 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, from about 16 grams to about 35 grams of the flame retardant composition is applied to the treated portion per square meter of the treated portion surface area. In particularly preferred embodiments, from about 18 grams to about 35 grams or from about 20 grams to about 35 grams of the flame retardant composition is applied per square meter of the treated portion surface area.

In other embodiments, from 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, from about 12 grams to about 30 grams of the flame retardant composition is applied per square meter of the treated portion surface area. More preferably, from 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, from 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, from about 18 grams to about 30 grams or from about 20 grams to about 30 grams of the flame retardant composition is applied per square meter of the treated portion surface area.

In a further embodiment, from about 10 grams to about 25 grams of the flame retardant composition is applied per square meter of the treated portion surface area of the treated portion. Preferably, from about 12 grams to about 25 grams of the flame retardant composition is applied per square meter of the treated portion surface area. More preferably, from 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, from 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, from about 18 grams to about 25 grams or from about 20 grams to about 25 grams of the flame retardant composition is applied per square meter of the treated portion surface area of the treated portion.

The treated portion of the package may comprise at least about 0.1 grams of one or more flame retardant compounds per square meter of surface area of the treated portion. Preferably, the treated portion of the package comprises at least about 0.5 grams of one or more flame retardant compounds per square meter of surface area of the treated portion. More preferably, the treated portion of the package comprises at least about 1.0 gram of one or more flame retardant compounds per square meter of surface area of the treated portion. Even more preferably, the treated portion of the package comprises at least about 2.0 grams of one or more flame retardant compounds per square meter of surface area of the treated portion. In particularly preferred embodiments, the treated portion of the package comprises at least about 3.0 grams of one or more flame retardant compounds per square meter of surface area of the treated portion or at least about 4.0 grams of one or more flame retardant compounds per square meter of surface area of the treated portion or at least about 5.0 grams of one or more flame retardant compounds per square meter of surface area of the treated portion.

Preferably, the treated portion of the package comprises less than or equal to about 12 grams of one or more flame retardant compounds per square meter of surface area of the treated portion. More preferably, the treated portion of the package comprises less than or equal to about 10 grams of one or more flame retardant compounds per square meter of surface area of the treated portion. Even more preferably, the treated portion of the package comprises less than or equal to about 8 grams of one or more flame retardant compounds per square meter of surface area of the treated portion.

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

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

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

In the aerosol-generating article according to the invention, the content of the one or more flame retardant compounds in the treated portion is preferably 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, preferably 30 seconds, using a resistive heating coil. The term "not ignited" is used herein to particularly mean that combustion of the package defining the aerosol-generating substrate is not initiated and that no flame is detected.

Preferably, the aerosol-generating article according to the invention does not ignite when subjected to the deep draw mode (Intense region) of the health canada, which mode comprises a pre-ignition step using a resistive heating coil, and is in a draw mode in which 55 ml is drawn at a time and every 30 seconds for 2 seconds in which 100% of the ventilation zone on the aerosol-generating article (if present) is blocked. More details on "smoking" parameters and standard test conditions are provided in ISO 3308 (conventional analytical smoking machine — definitions and standard conditions).

In some embodiments, the package comprises a packaging base material and is provided with a layer comprising one or more flame retardant compounds on a surface of the packaging base material facing the aerosol-generating substrate. In other embodiments, the package comprises a packaging base material and is provided with a layer comprising one or more flame retardant compounds on a surface of the packaging base material facing away from the aerosol-generating substrate. In a further embodiment, the package comprises a packaging base material and a layer comprising one or more flame retardant compounds is provided on both surfaces of the packaging base material.

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 packages for aerosol-generating articles according to the invention.

In some embodiments, the flame retardant composition comprises a polymer and a mixed salt based on at least one mono-, di-, and/or tri-carboxylic acid, at least one polyphosphoric acid, pyrophosphoric acid, and/or phosphoric acid, and alkali or alkaline earth metal hydroxides or salts, wherein the at least one mono-, di-, and/or tri-carboxylic 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.

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

In other embodiments, the flame retardant composition comprises a flame retardant modified with 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 Or higher fatty acids selected from capric acid, myristic acid, palmitic acid and combinations thereof.

As briefly described above, the aerosol-generating article of the present invention further comprises a downstream section at a location downstream of the rod of aerosol-generating substrate. The downstream section may include one or more downstream elements.

According to the invention, the downstream section of the aerosol-generating article may in particular comprise a mouthpiece element positioned downstream of and longitudinally aligned with the rod of aerosol-generating substrate.

Preferably, the mouthpiece element is located at the downstream end or mouth end of the aerosol-generating article and extends all the way to the mouth end of the aerosol-generating article.

Preferably, the mouthpiece element comprises at least one mouthpiece filter segment of fibrous filter material for filtering aerosols generated by the aerosol-generating substrate. Suitable fibrous filter materials will be known to the skilled person. Particularly preferably, the at least one mouthpiece filter segment comprises a cellulose acetate filter segment formed from cellulose acetate tow.

In certain preferred embodiments, the mouthpiece element is comprised of a single mouthpiece filter segment. In an alternative embodiment, the mouthpiece element comprises two or more mouthpiece filter segments axially aligned with one another in abutting end-to-end relationship.

In certain embodiments of the invention, the downstream segment may comprise an oral cavity at the downstream end downstream of the mouthpiece element as described above. The mouth end cavity may be defined by a hollow tubular element provided at the downstream end of the mouthpiece. Alternatively, the mouth end cavity may be defined by an outer wrapper of the mouthpiece element, wherein the outer wrapper extends from the mouthpiece element in a downstream direction.

The mouthpiece element may optionally include a flavoring agent, which may be provided in any suitable form. For example, the mouthpiece element may comprise one or more capsules, beads or particles of flavourant, or one or more flavour-bearing filaments or filaments.

In certain preferred embodiments, the downstream section of the aerosol-generating article further comprises a support element located immediately downstream of the rod of aerosol-generating substrate. The mouthpiece element is preferably located downstream of the support element.

The support element may be formed from any suitable material or combination of materials. For example, the support element may be formed from one or more materials selected from the group consisting of: cellulose acetate, cardboard, crimped paper, such as crimped heat-resistant paper or crimped parchment paper, and polymeric materials, such as Low Density Polyethylene (LDPE). In a preferred embodiment, the support element is formed from cellulose acetate. Other suitable materials include Polyhydroxyalkanoate (PHA) fibers.

The support element may comprise a first hollow tubular section. In a preferred embodiment, the support element comprises a hollow cellulose acetate tube.

The support elements are arranged substantially in alignment with the strips. This means that the length dimension of the support element is arranged substantially parallel to the longitudinal direction of the strip and the article, e.g. within +/-10 degrees of being parallel to the longitudinal direction of the strip. In a preferred embodiment, the support element extends along the longitudinal axis of the strip.

Preferably, the outer diameter of the support element is substantially equal to the outer diameter of the rod of aerosol-generating substrate and the outer diameter of the aerosol-generating article.

The peripheral wall of the support element may have a thickness of at least 1 mm, preferably at least about 1.5 mm, more preferably at least about 2 mm.

The support element may have a length of between about 5 millimeters and about 15 millimeters.

Preferably, the support element has a length of at least about 6 mm, more preferably at least about 7 mm.

In a preferred embodiment, the support element has a length of less than about 12 millimeters, more preferably less than about 10 millimeters.

In some embodiments, the support element has a length of about 5 millimeters to about 15 millimeters, preferably about 6 millimeters to about 15 millimeters, more preferably about 7 millimeters to about 15 millimeters. In other embodiments, the support element has a length of about 5 millimeters to about 12 millimeters, preferably about 6 millimeters to about 12 millimeters, more preferably about 7 millimeters to about 12 millimeters. In further embodiments, the support element has a length of about 5 millimeters to about 10 millimeters, preferably about 6 millimeters to about 10 millimeters, more preferably about 7 millimeters to about 10 millimeters.

In a preferred embodiment, the support element has a length of about 8 mm.

In some embodiments, the downstream section further comprises an aerosol-cooling element located immediately downstream of the support element. The mouthpiece element is preferably located downstream of both the support element and the aerosol-cooling element. Particularly preferably, the mouthpiece element is located immediately downstream of the aerosol-cooling element. For example, the mouthpiece element may abut a downstream end of the aerosol-cooling element.

The aerosol-cooling element is arranged substantially in alignment with the rod. This means that the length dimension of the aerosol-cooling element is arranged substantially parallel to the longitudinal direction of the rod and article, for example within +/-10 degrees of being parallel to the longitudinal direction of the rod. In a preferred embodiment, the aerosol-cooling element extends along the longitudinal axis of the rod.

Preferably, the outer diameter of the aerosol-cooling element is substantially equal to the outer diameter of the rod of aerosol-generating substrate and the outer diameter of the aerosol-generating article.

In some embodiments, the aerosol-cooling element is in the form of a hollow tubular section defining a cavity extending from an upstream end of the aerosol-cooling element all the way to a downstream end of the aerosol-cooling element, and a ventilation zone is provided at a location along the hollow tubular section.

As used herein, the term "hollow tubular section" is used to refer to a generally elongated element defining a lumen or airflow passage along its longitudinal axis. In particular, the term "tubular" will be used hereinafter to refer to a tubular element having a substantially cylindrical cross-section and defining at least one gas flow conduit establishing uninterrupted fluid communication between an upstream end of the tubular element and a downstream end of the tubular element. However, it should be understood that alternative geometries (e.g., alternative cross-sectional shapes) of the tubular element may be possible.

The hollow tubular section provides an unrestricted flow passage. This means that the hollow tubular section provides a negligible level of resistance to suction (RTD). Thus, the flow channel should be free of any components that would impede the flow of air in the longitudinal direction. Preferably, the flow channel is substantially empty.

When used to describe an aerosol-cooling element, the term "elongate" means that the aerosol-cooling element has a length dimension that is greater than its width dimension or its diameter dimension, for example twice its width dimension or its diameter dimension or more.

The peripheral wall of the aerosol-cooling element may have a thickness of less than about 2.5 mm, preferably less than about 1.5 mm, more preferably less than about 1250 microns, even more preferably less than about 1000 microns. In a particularly preferred embodiment, the peripheral wall of the aerosol-cooling element has a thickness of less than about 900 microns, preferably less than about 800 microns.

The aerosol-cooling element may have a length of between 5 mm and 15 mm.

Preferably, the aerosol-cooling element has a length of at least about 6 mm, more preferably at least about 7 mm.

In preferred embodiments, the aerosol-cooling element has a length of less than about 12 mm, more preferably less than about 10 mm.

In some embodiments, the aerosol-cooling element has a length of about 5 millimeters to about 15 millimeters, preferably about 6 millimeters to about 15 millimeters, more preferably about 7 millimeters to about 15 millimeters. In other embodiments, the aerosol-cooling element has a length of about 5 millimeters to about 12 millimeters, preferably about 6 millimeters to about 12 millimeters, more preferably about 7 millimeters to about 12 millimeters. In a further embodiment, the aerosol-cooling element has a length of about 5 mm to about 10 mm, preferably about 6 mm to about 10 mm, more preferably about 7 mm to about 10 mm.

In a particularly preferred embodiment of the invention, the aerosol-cooling element has a length of less than 10 mm. For example, in a particularly preferred embodiment, the aerosol-cooling element has a length of 8 mm. In such embodiments, the aerosol-cooling element therefore has a relatively short length compared to the aerosol-cooling elements of prior art aerosol-generating articles. A reduction of the length of the aerosol-cooling element is possible due to the optimized effectiveness of the hollow tubular section forming the aerosol-cooling element in the cooling and nucleation of the aerosol. The reduction in length of the aerosol-cooling element advantageously reduces the risk of deformation of the aerosol-generating article due to compression during use, as the aerosol-cooling element typically has a lower resistance to deformation than the mouthpiece. Furthermore, reducing the length of the aerosol-cooling element may provide a cost benefit to the manufacturer, as the cost per unit length of the hollow tubular segment is typically higher than the cost of other elements such as the mouthpiece element.

The ratio between the length of the aerosol-cooling element and the length of the rod of aerosol-generating substrate may be from about 0.25 to about 1.

The aerosol-cooling element may be formed from any suitable material or combination of materials. For example, the aerosol-cooling element may be formed from one or more materials selected from the group consisting of: cellulose acetate, cardboard, crimped paper, such as crimped heat-resistant paper or crimped parchment, and polymeric materials, such as Low Density Polyethylene (LDPE). Other suitable materials include Polyhydroxyalkanoate (PHA) fibers.

In a preferred embodiment, the aerosol-cooling element is formed from cellulose acetate.

The ventilation zone comprises a plurality of perforations through a peripheral wall of the aerosol-cooling element. Preferably, the ventilation zone comprises at least one row of circumferential perforations. In some embodiments, the vented zone may comprise two circumferential rows of perforations. For example, the perforations may be formed on a production line during manufacture of the aerosol-generating article. Preferably, each row of circumferential perforations comprises 8 to 30 perforations.

Aerosol-generating articles according to the present invention may have a ventilation level of at least about 5%.

Throughout this specification, the term "ventilation level" is used to denote the volumetric ratio of airflow into the aerosol-generating article via the ventilation zone (ventilation airflow) to the sum of the aerosol airflow and the ventilation airflow. The greater the level of ventilation, the higher the dilution of the aerosol stream delivered to the consumer.

Preferably, aerosol-generating articles according to the present invention may have a ventilation level of at least about 10%, more preferably at least about 15%, even more preferably at least about 20%. In a particularly preferred embodiment, the aerosol-generating article according to the invention has a ventilation level of at least about 25%. Without wishing to be bound by theory, the inventors have found that the temperature drop caused by the cooler outside air entering the hollow tubular section via the ventilation zone may have a beneficial effect on the nucleation and growth of aerosol particles. The rapid cooling caused by the entry of external air into the hollow tubular section via the ventilation zone may advantageously be used to promote the nucleation and growth of aerosol droplets. At the same time, however, the entry of outside air into the hollow tubular section has the direct disadvantage of diluting the aerosol stream delivered to the consumer. The inventors have surprisingly found that when the ventilation level is within the above range, the dilution effect on the aerosol, which can be assessed by inter alia measuring the effect on the delivery of an aerosol-forming agent (such as glycerol) comprised in the aerosol-generating substrate, is advantageously minimized.

In some embodiments, the aerosol-generating article may further comprise an additional cooling element defining a plurality of longitudinally extending channels so as to make a high surface area available for heat exchange. In other words, one such additional cooling element is adapted to essentially act as a heat exchanger. The plurality of longitudinally extending channels may be defined by a sheet of material that has been pleated, gathered or folded to form the channels. The plurality of longitudinally extending channels may be defined by a single sheet of material that has been pleated, gathered and folded to form the plurality of channels. The sheet may have been crimped prior to pleating, gathering or folding. Alternatively, the plurality of longitudinally extending channels may be defined by a plurality of sheets that have been crimped, pleated, gathered and folded to form the plurality of channels. In some embodiments, the plurality of longitudinally extending channels may be defined by a plurality of sheets that have been rolled, pleated, gathered, or folded together, i.e., by two or more sheets that have entered into an overlying arrangement and then rolled, pleated, gathered, or folded into one. As used herein, the term "sheet" means a layered element having a width and a length that is substantially greater than its thickness.

In other embodiments, the aerosol-cooling element may be provided in the form of one such cooling element comprising a plurality of longitudinally extending channels.

One such additional cooling element defines and may have a total surface area of between about 300 square millimeters per millimeter length and about 1000 square millimeters per millimeter length.

The additional cooling element preferably comprises a sheet material selected from the group consisting of metal foil, polymer sheet and substantially non-porous paper or cardboard. In some embodiments, the aerosol-cooling element may comprise a sheet material selected from the group consisting of: polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polylactic acid (PLA), cellulose Acetate (CA), and aluminum foil. In a particularly preferred embodiment, the additional cooling element comprises a sheet of PLA.

The aerosol-generating substrate may further comprise an upstream section at a position upstream of the rod of aerosol-generating substrate. The upstream section may include one or more upstream elements. In some embodiments, the upstream section may comprise an upstream element arranged immediately upstream of the rod of aerosol-generating substrate.

Preferably, the aerosol-generating article of the present invention may comprise an upstream element located upstream of and adjacent to the aerosol-generating substrate, wherein the upstream section comprises at least one upstream element. The upstream element advantageously prevents direct physical contact with the upstream end of the aerosol-generating substrate. In particular, where the aerosol-generating substrate comprises a susceptor element, the upstream element may prevent direct physical contact with an upstream end of the susceptor element. This helps to prevent the susceptor element from being displaced or deformed during handling or transportation of the aerosol-generating article. This in turn helps to fix the form and position of the susceptor element. Furthermore, the presence of the upstream element helps to prevent any loss of substrate.

The upstream element may also provide an improved appearance to the upstream end of the aerosol-generating article. Furthermore, if desired, the upstream element may be used to provide information about the aerosol-generating article, such as information about the brand, flavour, content or details of the aerosol-generating device with which the article is intended to be used.

The upstream element may be a porous rod element. Preferably, the porous rod element does not alter the resistance to draw of the aerosol-generating article. Preferably, the upstream element has a porosity of at least about 50% in the longitudinal direction of the aerosol-generating article. More preferably, the upstream element has a porosity in the longitudinal direction of between about 50% and about 90%. The porosity of the upstream element in the longitudinal direction is defined by the ratio of the cross-sectional area of the material forming the upstream element to the internal cross-sectional area of the aerosol-generating article at the location of the upstream element.

The upstream element may be made of a porous material or may comprise a plurality of openings. This can be achieved, for example, by laser perforation. Preferably, the plurality of openings are homogeneously distributed over the cross-section of the upstream element.

The porosity or permeability of the upstream element may advantageously be varied so as to provide a desired overall resistance to draw of the aerosol-generating article.

Preferably, the RTD of the upstream element is at least about 5 mm H ₂ And (O). More preferably, the RTD of the upstream element is at least about 10 mm H ₂ And O. Even more preferably, the RTD of the upstream element is at least about 15 mm H ₂ And O. In a particularly preferred embodiment, the RTD of the upstream element is at least about 20 mm H ₂ O。

The RTD of the upstream element is preferably less than or equal to about 80 mm H ₂ And O. More preferably, the RTD of the upstream element is less than or equal to about 60 mm H ₂ And O. Even more preferably, the RTD of the upstream element is less than or equal to about 40 mm H ₂ O。

In alternative embodiments, the upstream element may be formed of an air impermeable material. In such embodiments, the aerosol-generating article may be configured such that air flows into the rod of aerosol-generating substrate through a suitable ventilation means provided in the package.

The upstream element may be made of any material suitable for use in aerosol-generating articles. The upstream element may, for example, be made of the same material as one of the other components used in the aerosol-generating article (e.g. the mouthpiece, the cooling element or the support element). Suitable materials for forming the upstream element include filter materials, ceramics, polymeric materials, cellulose acetate, cardboard, zeolites or aerosol generating substrates. Preferably, the upstream element is formed from a cellulose acetate rod.

Preferably, the upstream element is formed of a heat-resistant material. For example, preferably the upstream element is formed from a material that is resistant to temperatures up to 350 degrees celsius. This ensures that the upstream element is not adversely affected by the heating means used to heat the aerosol-generating substrate.

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

Preferably, the upstream element has a length of between about 1 mm and about 10 mm, preferably between about 3 mm and about 8 mm, more preferably between about 4 mm and about 6 mm. In a particularly preferred embodiment, the upstream element has a length of about 5 millimeters. The length of the upstream element may advantageously be varied in order to provide a desired 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 may be increased in order to maintain the same overall length of the article.

The upstream element is preferably defined by a wrapper. The wrapper defining the upstream element is preferably a rigid rod wrapper, e.g., a rod wrapper having a basis weight of at least about 80 grams per square meter (gsm) or at least about 100gsm or at least about 110 gsm. This provides structural rigidity to the upstream element.

Preferably, in the aerosol-generating article according to the invention, the package is metal-free. As used herein, with respect to the present invention, the term "metal" means the metal content in an oxidation state of 0, i.e. the metal content of the element in the package in free form. Thus, metal content, such as alkali or alkaline earth metals, that may be present in ionic form or in combination with another element in one or more flame retardant compounds of the flame retardant composition are not encompassed by the term "metal" as used herein.

In other words, the package of the aerosol-generating article according to the invention preferably does not contain any metal having an oxidation state of 0.

Accordingly, the aerosol-generating article according to the present invention advantageously does not comprise a metal foil which acts as a heat shielding element. In particular, the aerosol-generating substrate is not limited to one such metal foil thermal barrier element.

Aerosol-generating articles according to the present invention as described above may be manufactured by a process comprising a first step of providing a continuous rod of aerosol-generating substrate, wherein the aerosol-generating substrate has a density of greater than about 300 mg/cc. One such method comprises a second step of defining a continuous rod of aerosol-generating substrate with a package comprising a flame retardant composition, wherein the flame retardant composition comprises one or more flame retardant compounds. Further, the method includes a third step of cutting the defined continuous strip into discrete strips, each discrete strip defined by a portion of a package containing the flame retardant composition.

The flame retardant composition may be applied to at least one side of the packaging base material of the package by an application process based on size pressing, spraying, printing or coating.

In particular, aerosol-generating articles according to the present invention may be used in aerosol-generating systems comprising an aerosol-generating article and an electrically operated aerosol-generating device, wherein the aerosol-generating device comprises a heater and an elongate heating chamber configured to receive the aerosol-generating article such that an aerosol-generating substrate of the article is heated in the heating chamber.

In some embodiments, the heater may be adapted to be inserted into an aerosol-generating substrate of an article when the article is received into the heating chamber. For example, the heater may be in the form of a heating bar or pin.

In other embodiments, the heater may comprise a substantially cylindrical, elongated heating element, and the heating chamber is disposed about a circumferential longitudinal surface of the heater. Thus, during use, thermal energy supplied by the heater travels radially outward from the surface of the heater into the heating chamber and the aerosol-generating article. However, other shapes and configurations of heaters and heating chambers may alternatively be used. The heater may comprise a plurality of separate heating elements, the various heating elements being operated independently of one another, such that different elements may be activated at different times to heat the aerosol-generating article. For example, the heater may comprise a plurality of axially aligned heating elements providing a plurality of separate heating zones along the length of the heater. Each heating element may have a length that is substantially less than the overall length of the heater. Thus, when an individual heating element is activated, it supplies thermal energy to a portion of the aerosol-generating substrate located radially adjacent the heating element without substantially heating the remainder of the aerosol-generating substrate. Thus, different portions of the aerosol-generating substrate may be heated independently and at different times.

Alternatively or additionally, the heater may comprise a plurality of elongate longitudinally extending heating elements at different positions around the longitudinal axis of the heater. Thus, when an individual heating element is activated, it provides thermal energy to a longitudinal portion of the aerosol-generating substrate located substantially parallel and adjacent to the heating element. This arrangement also allows the aerosol-generating substrate to be heated independently in different parts.

In some of these embodiments comprising a heater element disposed at a peripheral location relative to the heating chamber, the aerosol-generating system may further comprise an insulating means arranged between the heating chamber and an exterior of the device to reduce heat loss from the heated aerosol-generating substrate.

In a further embodiment, the aerosol-generating article comprises a susceptor arranged within the aerosol-generating substrate, the susceptor being in thermal contact with the aerosol-generating substrate, and the heater is in the form of an inductive heating device comprising one or more induction coils. Electromagnetic energy released by the induction coil is absorbed by the susceptor and converted to heat, which is then transferred to the aerosol-generating substrate primarily by conduction.

Drawings

The invention will be further described hereinafter with reference to the figures of the accompanying drawings, in which:

figure 1 shows a schematic side cross-sectional view of an aerosol-generating article according to an embodiment of the present invention; and

figure 2 shows a schematic side cross-sectional view of another aerosol-generating article according to another embodiment of the present invention.

Detailed Description

The aerosol-generating article 10 shown in figure 1 comprises a rod 12 of aerosol-generating substrate 12 and a downstream section 14 at a position downstream of the rod 12 of aerosol-generating substrate. Furthermore, the aerosol-generating article 10 comprises an upstream section 16 at a position upstream of the rod 12 of aerosol-generating substrate. Thus, the aerosol-generating article 10 extends from an upstream or distal end 18 to a downstream or mouth end 20.

The aerosol-generating article has an overall length of about 45 millimetres.

The downstream section 14 comprises a support element 22 located immediately downstream of the rod 12 of aerosol-generating substrate, the support element 22 being longitudinally aligned with the rod 12. In the embodiment of figure 1, the upstream end of the support element 18 abuts the downstream end of the rod 12 of aerosol-generating substrate. In addition, the downstream section 14 comprises an aerosol-cooling element 24 located immediately downstream of the support element 22, the aerosol-cooling element 24 being longitudinally aligned with the rod 12 and the support element 22. In the embodiment of fig. 1, the upstream end of the aerosol-cooling element 24 abuts the downstream end of the support element 22. In the embodiment of fig. 1, the support element 22 and the aerosol-cooling element 24 together define an intermediate hollow section 50 of the aerosol-generating article 10.

The support element 22 comprises a first hollow tubular section 26. The first hollow tubular section 26 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The first hollow tubular section 26 defines an internal cavity 28 extending from an upstream end 30 of the first hollow tubular section all the way to a downstream end 32 of the first hollow tubular section 20. The interior cavity 28 is substantially empty and thus a substantially non-limiting flow of air is achieved along the interior cavity 28.

The first hollow tubular section 26 has a length of about 8 millimeters, an outer diameter of about 7.25 millimeters, and an inner diameter of about 1.9 millimeters. Thus, the thickness of the peripheral wall of the first hollow tubular section 26 is about 2.67 mm.

The aerosol-cooling element 24 comprises a second hollow tubular section 34. The second hollow tubular section 34 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The second hollow tubular section 34 defines an internal cavity 36 extending from an upstream end 38 of the second hollow tubular section all the way to a downstream end 40 of the second hollow tubular section 34. The interior cavity 36 is substantially empty and thus a substantially non-restrictive flow of air is achieved along the interior cavity 36.

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

The aerosol-generating article 10 comprises a ventilation zone 60 provided at a location along the second hollow tubular section 34. In more detail, the venting zone is provided about 2 mm from the upstream end of the second hollow tubular section 34. The ventilation level of the aerosol-generating article 10 is about 25%.

In the embodiment of fig. 1, the downstream segment 14 further comprises a mouthpiece element 42 at a location downstream of the intermediate hollow segment 50. In more detail, the mouthpiece element 42 is positioned immediately downstream of the aerosol-cooling element 24. As shown in the diagram of fig. 1, the upstream end of the mouthpiece element 42 abuts the downstream end 40 of the aerosol-cooling element 18.

The mouthpiece element 42 is provided in the form of a cylindrical filter segment of low density cellulose acetate. The mouthpiece element 42 has a length of about 12 mm and an outer diameter of about 7.25 mm.

The rod 12 comprises an aerosol-generating substrate of one of the types described above. The density of the aerosol-generating substrate is about 600 mg/cc.

The rod 12 of aerosol-generating substrate has an outer diameter of about 7.25 millimetres and a length of about 12 millimetres.

The aerosol-generating article 10 further comprises an elongate susceptor 44 within the rod 12 of aerosol-generating substrate. In more detail, the susceptor 44 is arranged substantially longitudinally within the aerosol-generating substrate so as to be substantially parallel to the longitudinal direction of the rod 12. As shown in the diagram of fig. 1, the susceptor 44 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 44 is in thermal contact with the aerosol-generating substrate. The susceptor 44 extends from the upstream end of the strip 12 all the way to the downstream end. In practice, the susceptor 44 has substantially the same length as the rod 12 of aerosol-generating substrate.

In the embodiment of fig. 1, the susceptor 44 is provided in the form of a strip and has a length of about 12 millimeters, a thickness of about 60 micrometers, and a width of about 4 millimeters.

The upstream section 16 comprises an upstream element 46 located immediately upstream of the rod 12 of aerosol-generating substrate, the upstream element 46 being longitudinally aligned with the rod 12. In the embodiment of figure 1, the downstream end of the upstream element 46 abuts the upstream end of the rod 12 of aerosol-generating substrate. This advantageously prevents the susceptor 44 from being removed. In addition, this ensures that the consumer does not accidentally contact the heated susceptor 44 after use.

The upstream element 46 is provided in the form of a cylindrical cellulose acetate rod defined by a rigid wrapper. The upstream element 46 has a length of about 5 mm. The RTD of the upstream element 46 is about 30 mm H ₂ O。

As shown in the diagram of figure 1, the aerosol-generating article 10 further comprises a wrapper 70 defining the rod 12 of aerosol-generating substrate. The wrapper 70 comprises a packaging base material having a basis weight of about 90 grams per square meter. Further, package 70 comprises a flame retardant composition comprising one or more flame retardant compounds.

In more detail, the flame retardant composition is provided at least in a treatment portion 72 of the package (extending between the proximal and distal ends of the rod 12 of aerosol-generating substrate). The treated portion 72 contains about 3.5 grams of one or more flame retardant compounds per square meter of the surface area of the treated portion 72. Thus, the treated portion 72 of the wrapper 70 has a total basis weight that is greater than the basis weight of the packaging base material. In the embodiment of fig. 1, the treatment portion 72 has a length that substantially matches the length of the rod 12 of aerosol-generating substrate and extends over substantially the entire outer surface area of the rod 12 of aerosol-generating substrate.

The aerosol-generating article 110 shown in fig. 2 shares many features in common with the aerosol-generating article 10 of fig. 1, and its differences from the aerosol-generating article 10 will be described below.

As shown in fig. 2, the aerosol-generating article 110 comprises a rod 12 of aerosol-generating substrate 12 and a modified downstream section 114 at a location downstream of the rod 12 of aerosol-generating substrate. Furthermore, the aerosol-generating article 110 does not comprise an upstream section.

Similar to the downstream section 14 of the aerosol-generating article 10, the modified downstream section 114 of the aerosol-generating article 110 comprises a support element 22 located immediately downstream of the rod 12 of aerosol-generating substrate, the support element 22 being longitudinally aligned with the rod 12, wherein an upstream end of the support element 22 abuts a downstream end of the rod 12 of aerosol-generating substrate.

In addition, the modified downstream section 114 comprises an aerosol-cooling element 124 located immediately downstream of the support element 22, the aerosol-cooling element 124 being longitudinally aligned with the rod 12 and the support element 22. In more detail, the upstream end of the aerosol-cooling element 124 abuts the downstream end of the support element 22.

In contrast to the downstream section 14 of the aerosol-generating article 10, the aerosol-cooling element 124 of the modified downstream section 114 comprises a plurality of longitudinally extending channels that offer low or substantially zero resistance to the passage of air through the rod. In more detail, the aerosol-cooling element 124 is formed from a preferably non-porous sheet material selected from the group consisting of metal foil, polymeric sheet material, and substantially non-porous paper or paperboard. In particular, in the embodiment shown in fig. 2, the aerosol-cooling element 124 is provided in the form of a rolled and gathered sheet of polylactic acid (PLA). The aerosol-cooling element 124 has a length of about 8 millimeters and an outer diameter of about 7.25 millimeters.

Similar to the embodiment of figure 1, the aerosol-generating article 110 of figure 2 further comprises a wrapper 70 defining the rod 12 of aerosol-generating substrate. The wrapper 70 comprises a packaging base material having a basis weight of about 90 grams per square meter. Further, package 70 comprises a flame retardant composition comprising one or more flame retardant compounds.

Claims

1. An aerosol-generating article for generating an inhalable aerosol upon heating, the aerosol-generating article comprising:

a rod of aerosol-generating substrate comprising at least one aerosol former, wherein the aerosol-generating substrate has an aerosol former content of at least about 10% by dry weight;

a downstream section at a location downstream of the rod of aerosol-generating substrate; and

a wrapper defining at least the rod of aerosol-generating substrate;

wherein the aerosol-generating substrate has a density of greater than about 300 mg/cc; and is

Wherein the package comprises a flame retardant composition comprising one or more flame retardant compounds.

2. An aerosol-generating article according to claim 1, wherein the aerosol-generating substrate has a density of greater than about 350 mg/cc.

3. An aerosol-generating article according to claim 1, wherein the aerosol-generating substrate has a density of greater than about 400 mg/cc.

4. An aerosol-generating article according to any of claims 1 to 3, wherein the rod of aerosol-generating substrate comprises a gathered sheet of homogenized tobacco material.

5. An aerosol-generating article according to any of claims 1 to 3, wherein the rod of aerosol-generating substrate comprises a gel composition comprising at least one gelling agent, a alkaloid compound and an aerosol former.

6. An aerosol-generating article according to any preceding claim, wherein the rod of aerosol-generating substrate further comprises a susceptor element arranged within the aerosol-generating substrate.

7. An aerosol-generating article according to any preceding claim, wherein the package comprises a packaging base material and a layer comprising a flame retardant composition provided on a surface of the packaging base material facing the aerosol-generating substrate, a surface of the packaging base material facing away from the aerosol-generating substrate, or both.

8. An aerosol-generating article according to any one of claims 1 to 7, wherein the flame retardant composition comprises a polymer and a mixed salt based on at least one mono-, di-, and/or tricarboxylic acid, at least one polyphosphoric acid, pyrophosphoric acid, and/or phosphoric acid, and a hydroxide or salt of an alkali or alkaline earth metal, wherein the at least one mono-, di-, 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.

9. An aerosol-generating article according to claim 8, wherein the flame retardant composition further comprises a carbonate of an alkali or alkaline earth metal.

10. An aerosol-generating article according to any one of claims 1 to 7, wherein the flame retardant composition comprises a flame retardant treated with at least one C ₁₀ Or higher fatty acids, tall Oil Fatty Acids (TOFA), phosphorylated linseed oil, phosphorylated downstream corn oil modified cellulose.

11. An aerosol-generating article according to any preceding claim, wherein the rod of aerosol-generating substrate has a length of less than about 40 millimetres.

12. An aerosol-generating article according to any preceding claim, wherein the rod of aerosol-generating substrate has a length of at least about 10 millimetres.

13. An aerosol-generating article according to any preceding claim, wherein the overall length of the aerosol-generating article is less than about 70 millimetres.

14. An aerosol-generating article according to any preceding claim, wherein the wrapper does not comprise metal.

15. A method of manufacturing an aerosol-generating article for generating an inhalable aerosol upon heating, the method comprising:

providing a continuous rod of aerosol-generating substrate, wherein the aerosol-generating substrate has a density of greater than about 300 mg/cc, the aerosol-generating substrate comprising at least one aerosol former, wherein the aerosol-generating substrate has an aerosol former content of at least about 10% by dry weight;

defining a continuous rod of the aerosol-generating substrate with a wrapper comprising a flame retardant composition comprising one or more flame retardant compounds;

cutting the defined continuous strip into discrete strips, each discrete strip defined by a portion of the wrapper comprising the flame retardant composition.

16. The method of claim 15, wherein the layer of the flame retardant composition is applied to at least one side of the packaging base material of the wrapper by an application process based on size pressing, spraying, printing or coating.

17. An aerosol-generating system comprising an electrically operated aerosol-generating device comprising means for heating a rod of the aerosol-generating substrate to a temperature sufficient to generate an aerosol from the aerosol-generating substrate, and an aerosol-generating article according to any of claims 1 to 14.