ES3040636T3 - Aerosol-generating article with combustion preventing wrapper - Google Patents

Abstract

An aerosol-generating article (10; 110) is provided for producing an inhalable aerosol upon heating. The aerosol-generating article (10; 110) comprises: a rod (12) of aerosol-generating substrate extending from a proximal end to a distal end, upstream of the proximal end; a downstream section (14) located downstream of the rod (12); and a sheath (70) surrounding at least the rod (12), said sheath being composed of a base material of a determined basis weight. At least one treated portion (72) of the sheath, extending between the proximal and distal ends of the rod, is composed of a flame-retardant material including one or more flame-retardant compounds. The treated portion (72) of the sheath (70) therefore has a total basis weight greater than that of the base material. The treated portion (72) comprises at least approximately 2 grams of one or more flame-retardant compounds per square meter of surface area of the treated portion. (Automatic translation using Google Translate, not legally binding)

Description

DESCRIPTION

Aerosol generating device with combustion-preventing casing

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

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

In a conventional cigarette, a user applies a flame to the distal end of the cigarette while inhaling through the proximal end. The heat generated locally by the flame and the oxygen in the air inhaled through the cigarette ignites the distal end, and the combustion of the tobacco stick and surrounding wrapper produces inhalable smoke. In contrast, in heated aerosol-generating articles, the aerosol is generated by a gentler transfer of heat from a heat source to an aerosol-generating substrate or physically separate material, which may be located in contact with, within, around, or downstream of the heat source. During use of the aerosol-generating article, volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source and are carried along in the air inhaled through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol.

A number of prior art documents describe aerosol-generating devices for the consumption of aerosol-generating articles. Such devices include, for example, electrically heated aerosol-generating devices in which an aerosol is generated by heat transfer from one or more electrical heating elements of the aerosol-generating device to the aerosol-generating substrate of a heated aerosol-generating article. For example, electrically heated aerosol-generating devices comprising an internal heating sheet adapted for insertion into the aerosol-generating substrate have been proposed. Alternatively, inductively heated aerosol-generating articles comprising an aerosol-generating substrate and a susceptor disposed within the aerosol-generating substrate have also been proposed.

WO 2013/076128 A1 describes a method for applying at least one area of additional material to a base fabric comprising providing a suspension of fibrous material in a liquid, forming a base fabric of fibrous material and liquid from the suspension, applying at least one area of additional material comprising fibrous material and from approximately 25 percent calcium carbonate to approximately 140 percent by weight of the fibrous material to the base fabric, the base fabric having a liquid content of between approximately 20 percent and approximately 98 percent by weight when the additional material is applied, and drying the base fabric with the additional material thereon. At the location where the additional material is applied to the base fabric, the base fabric retains sufficient moisture content, from approximately 20 percent to 98 percent by weight, preferably from 85 percent to 98 percent by weight, so that the additional solution is able to adhere to the base fabric. Preferably, the additional material comprises fibrous material and from approximately 30 percent to approximately 80 percent calcium carbonate by dry weight of the fibrous material. WO 2013/076128 A1 further describes a smoking article comprising a paper wrapper, wherein the paper wrapper comprises at least one area of additional material, wherein the additional material comprises fibrous material and at least 25 percent calcium carbonate by weight of the fibrous material.

US patent 2011/0315153 A1 describes a method for manufacturing a plurality of smoking articles in a manufacturing apparatus, comprising: providing a continuous web of wrapping paper having a permeability of less than 15 CU from a source thereof to an application section; applying a flame-retardant additive in a predetermined pattern to the wrapping paper web in the application section, wherein, in the area of the paper to which the pattern is applied; feeding the wrapping paper web to which the additive has been applied to a feed section; wrapping the wrapping paper web to which the additive has been applied around a tobacco material in the feed section to form a wrapped bar; and cutting the wrapped bar to form a plurality of smoking articles. Preferably, in the area of the paper to which the pattern is applied, the flame-retardant additive adds less than 10% to the weight of the paper, preferably less than 8%. Preferably, the flame-retardant additive material adds 0-5% to the weight of the paper, with the highest preference being 2-5%. US Patent 2011/0315153 A1 also describes a smoking article comprising: a bar of tobacco material; wrapping paper surrounding the bar of tobacco material; the wrapping paper having a pattern of a flame-retardant additive material applied thereto; and the wrapping paper having a permeability of less than 15 CU in areas without the flame-retardant additive and lower permeability in areas where the additive is applied. Figure 2 of US Patent 2011/0315153 A1 shows a smoking article 1 comprising a wrapped bar 2 of tobacco material with a filter 3 at one end. The filter is attached to the wrapped bar 2 with mouthpiece paper, and the wrapped bar 2 includes a tobacco core surrounded by wrapping paper. The wrapping paper has a pattern of a combustion retardant additive material applied thereto, the pattern comprising a plurality of separate bands 4. The pattern is located at the end of the bar filter 2.

WO 2021/205368 A1 describes a paper for use as a wrapper in aerosol-generating articles that heat up but do not burn. The paper includes a base weave made of cellulosic fibers combined with a flame-retardant filler. Alternatively or additionally, the paper may include a coating formed from a reduced-ignition composition.

Aerosol-generating articles, in which a tobacco-containing substrate is heated rather than burned, present a number of challenges not encountered with conventional smoking articles. The tobacco-containing substrates are typically heated to significantly lower temperatures compared to the temperatures reached by the combustion front in a conventional cigarette. However, the heating temperatures cannot be too low, as this can impact the release of nicotine from the tobacco-containing substrate and the delivery of nicotine to the consumer. Furthermore, to maximize heat transfer efficiency, it is generally desirable for the heat source to be located as close as possible to, and preferably in contact with, the aerosol-generating substrate.

Therefore, 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 disposed within the aerosol-generating substrate, the aerosol-generating substrate is typically enclosed by a wrapper that combines a paper layer with a metallic foil, such as aluminum foil. The metallic layer between the aerosol-generating substrate and the paper wrapper thus acts as a heat shield and prevents the paper wrapper from scorching or burning during use.

This is beneficial because it increases the safety of using the aerosol-generating item and prevents the release of paper combustion or pyrolysis products to the consumer during use. However, the inclusion of such metallic shielding makes the manufacturing process more complex and expensive, and can lead to a greater environmental impact of the aerosol-generating item when it is disposed of after use. Furthermore, since the original visual appearance of the aerosol-generating item is essentially preserved during use, it can be difficult to determine whether an aerosol-generating item has been used effectively.

Consequently, it would be desirable to provide a novel and improved aerosol-generating article that is easier to dispose of and has a reduced environmental impact, while at the same time being adapted to prevent scorching or burning during use. Secondly, there is a general need for a novel and improved aerosol-generating article that essentially prevents misuse of the article, such that the article can only be used correctly in an aerosol-generating device adapted to heat the aerosol-generating substrate and not as a conventional cigarette. It would also be desirable to provide such an aerosol-generating article that can be manufactured efficiently and at high speed, preferably without the need for significant modification of existing equipment.

Therefore, it would be convenient to provide a new and improved aerosol generating item that is suitable for achieving at least one of the convenient results described above.

According to the present invention, an aerosol generating article is provided for producing an inhalable aerosol upon heating, the aerosol generating article comprising: an aerosol generating substrate bar extending from a proximal end of the bar to a distal end of the bar upstream of the proximal end of the bar, wherein the aerosol generating substrate comprises at least one aerosol former, the aerosol former content of the aerosol generating substrate being at least 10 percent on a dry weight basis, and wherein the aerosol generating substrate bar further comprises a susceptor element disposed within the aerosol generating substrate; a downstream section at a location downstream of the aerosol generating substrate bar; and a wrap circumscribing at least the aerosol generating substrate bar, the wrap comprising a wrap base material having a dry basis weight. At least one treated portion of the sheath extending between the proximal and distal ends of the bar comprises a flame-retardant composition consisting of one or more flame-retardant compounds, such that the treated portion of the sheath has a total dry basis weight greater than the dry basis weight of the sheath base material. The treated portion comprises at least approximately 2 grams of the one or more flame-retardant compounds per square meter of surface area of the treated portion.

In accordance with the present invention, a method of manufacturing an aerosol-generating article for generating an inhalable aerosol upon heating is further provided, the method comprising: providing a continuous bar of aerosol-generating substrate, an aerosol-forming content of the aerosol-generating substrate being at least 10 percent on a dry weight basis; enclosing the continuous bar of aerosol-generating substrate with a wrapper, the wrapper comprising a wrapper base material having a dry basis weight; treating at least a portion of the wrapper with a flame-retardant composition comprising one or more flame-retardant compounds, such as to provide a treated portion of the wrapper having a total dry basis weight greater than the dry basis weight of the wrapper base material; cutting the continuous treated wrapped rod of the aerosol-generating substrate into discrete rods, each discrete rod extending from a proximal end of the discrete rod to a distal end of the discrete rod upstream of the proximal end of the discrete rod, such that in each discrete rod a treated portion of the wrapping comprises at least approximately 2 grams of the one or more flame-retardant compounds per square meter of surface area of the treated portion; the method further comprises providing each discrete rod of aerosol-generating substrate with a susceptor element disposed within the aerosol-generating substrate of the discrete rod.

In accordance with the present invention, an aerosol generating system is further provided comprising an aerosol generating article and an electrically operated aerosol generating device as described above, the aerosol generating device comprising means for heating the aerosol generating substrate bar to a temperature sufficient to generate an aerosol from the aerosol generating substrate.

As briefly described above, the present invention provides an aerosol-generating article for producing an inhalable aerosol upon heating, wherein the article comprises an aerosol-generating substrate bar extending from a proximal end of the bar to a distal end of the bar upstream of the proximal end of the bar, and a downstream section at a location downstream of the aerosol-generating substrate bar. In more detail, the present invention provides an aerosol-generating article for producing an inhalable aerosol upon heating to a temperature of approximately 100 degrees Celsius to approximately 800 degrees Celsius, preferably from approximately 150 degrees Celsius to approximately 500 degrees Celsius, more preferably from approximately 200 degrees Celsius to approximately 300 degrees Celsius.

These temperatures are significantly lower than the temperatures reached in a conventional cigarette after the combustion of a substrate containing tobacco, and even more significantly lower than the temperatures reached by commercially available cigarette lighters, which can be in the range of approximately 1000 degrees Celsius to 2000 degrees Celsius and even higher.

Furthermore, the aerosol-generating article comprises a wrapper enclosing at least the aerosol-generating substrate rod, the wrapper comprising a wrapper base material having a basis weight. Unlike existing aerosol-generating articles, at least a treated portion of the wrapper extending between the proximal and distal ends of the rod comprises a flame-retardant composition comprising one or more flame-retardant compounds. Therefore, the treated portion of the wrapper has a total basis weight greater than the basis weight of the wrapper base material. More specifically, the treated portion comprises at least approximately 2 grams of the one or more flame-retardant compounds per square meter of surface area of the treated portion.

The inventors have discovered that by enclosing the aerosol-generating substrate with a wrapper, where a treated portion of the wrapper comprises a flame-retardant composition, and this treated portion extends over the vast majority of the external surface area of the aerosol-generating substrate bar, it is advantageously possible to prevent the wrapper and the underlying aerosol-generating substrate from burning or scorching when heated during use. In other words, it is advantageously possible to essentially prevent combustion and pyrolysis of the components of the aerosol-generating articles according to the present invention.

In aerosol-generating articles according to the present invention, this is conveniently achieved without the need for an additional layer of metal foil or other heat-protective material incorporated into the aerosol-generating article. This simplifies the manufacturing process and can therefore reduce manufacturing costs. Disposing of an aerosol-generating article according to the present invention is also made easier, as there is no need to separate and recover valuable recyclable material, such as aluminum foil, when disposing of a used aerosol-generating article. Furthermore, the inventors have discovered that by enclosing the aerosol-generating substrate with a wrapper as described above, when the aerosol-generating substrate has been exposed, during use, to temperatures in the range of approximately 100 degrees Celsius to approximately 800 degrees Celsius, the aerosol-generating article appears significantly discolored, and the surface of the wrapper has turned dark brown or black. As such, it is immediately possible for the consumer to know whether an aerosol-generating article has been used previously and should be disposed of.

By adjusting the amount of flame retardant compound in the wrapper within the range described above (e.g., in terms of quantity per square meter of surface area of the treated portion), the extent to which the surface of the wrapper is treated with the flame retardant composition within the range described above (e.g., in terms of the fraction of the surface area of the bar over which the treated portion is extended), as well as the formulation of the flame retardant composition (i.e., the nature of the flame retardant compound or compounds), it is advantageously possible to improve the flame retardant properties of the wrapper and the aerosol generating article as a whole.

Therefore, the present invention provides an improved aerosol generating article that is capable of essentially preventing scorching and burning of the aerosol generating substrate and the wrapper during use. This is because by providing one or more flame-retardant compounds on or inside the wrapper, or both, it is possible to essentially prevent the heat supplied to the article to generate an aerosol from causing pyrolysis or combustion of the wrapper's base material.

The aerosol generating articles according to the present invention are advantageously easy to dispose of and have a reduced environmental impact, since there is no need for the articles to include a metallic foil layer as is commonly the case with existing aerosol generating articles.

Furthermore, an aerosol-generating article according to the present 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. In fact, unlike a conventional cigarette, an aerosol-generating article according to the invention essentially cannot be lit and cannot sustain combustion like a conventional cigarette.

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

As used herein, the term “aerosol-generating article” means an article in which an aerosol-generating substrate is heated to produce and deliver inhalable aerosol to a consumer. As used herein, the term “aerosol-generating substrate” denotes a substrate capable of releasing volatile compounds when heated to generate an aerosol.

A conventional cigarette is lit 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 ignite, and the resulting combustion produces inhalable smoke. In contrast, in heated aerosol-generating articles, an aerosol is generated by heating a flavor-generating substrate, such as tobacco. Known heated aerosol-generating articles include, for example, electrically heated aerosol-generating articles and aerosol-generating articles in which an aerosol is generated by the transfer of heat from a fuel element or heat source to a physically separated aerosol-forming material. For example, aerosol-generating articles according to the invention find particular application in aerosol-generating systems comprising an electrically heated aerosol-generating device having an internal heating plate adapted to be inserted into the aerosol-generating substrate rod. Aerosol-generating articles of this type are described in the prior art, for example, in document EP 0822670.

As used in the present description, the term “aerosol generating device” refers to a device comprising a heating element that interacts with the aerosol generating substrate of an aerosol generating article to generate an aerosol.

As used herein with reference to the present invention, the term “bar” denotes a generally cylindrical element with an essentially circular, oval, or elliptical cross-section. As used herein, the term “longitudinal” refers to the direction corresponding to the principal longitudinal axis of the aerosol-generating article, extending between the upstream and downstream ends of the aerosol-generating article. As used herein, the terms “upstream” and “downstream” describe the relative positions of elements, or portions thereof, of the aerosol-generating article with respect to the direction in which the 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 the direction perpendicular to the longitudinal axis. Any reference to the “cross-section” of the aerosol-generating article or a component of the aerosol-generating article refers to the cross-section unless otherwise stated.

The term “length” denotes the dimension of a component of the aerosol-generating article in the longitudinal direction. For example, it can be used to denote the dimension of the rod or elongated tubular elements in the longitudinal direction.

An aerosol-generating article according to the present invention comprises an aerosol-generating substrate bar. The aerosol-generating substrate bar extends from a proximal end of the bar to a distal end of the bar upstream of the proximal end of the bar. Furthermore, the aerosol-generating article comprises a downstream section located downstream of the aerosol-generating substrate bar.

In aerosol-generating articles according to the present invention, at least the aerosol-generating substrate bar is enclosed by a wrapper. This means that in the aerosol-generating articles according to the present invention, the same wrapper that encloses the aerosol-generating substrate bar may also enclose at least a portion of the downstream section or at least a portion of an optional additional component of the aerosol-generating article provided in a location upstream of the aerosol-generating substrate bar, or both.

The aerosol generating item can have a total length of approximately 35 millimeters to approximately 100 millimeters.

Preferably, the overall length of an aerosol-generating article according to the invention is at least approximately 38 millimeters. More preferably, the overall length of an aerosol-generating article according to the invention is at least approximately 40 millimeters. Even more preferably, the overall length of an aerosol-generating article according to the invention is at least approximately 42 millimeters.

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

In preferred embodiments, the overall length of the aerosol-generating article is approximately 38 millimeters to approximately 70 millimeters, with a higher preference of approximately 40 millimeters to approximately 70 millimeters, and an even higher preference of approximately 42 millimeters to approximately 70 millimeters. In other embodiments, the overall length of the aerosol-generating article is preferably approximately 38 millimeters to approximately 60 millimeters, with a higher preference of approximately 40 millimeters to approximately 60 millimeters, and an even higher preference of approximately 42 millimeters to approximately 60 millimeters. In further embodiments, the overall length of the aerosol-generating article is preferably approximately 38 millimeters to approximately 50 millimeters, with a higher preference of approximately 40 millimeters to approximately 50 millimeters, and an even higher preference of approximately 42 millimeters to approximately 50 millimeters. In an illustrative embodiment, the overall length of the aerosol-generating article is approximately 45 millimeters.

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

In preferred embodiments, the overall length of an aerosol-generating article is approximately 40 millimeters to approximately 95 millimeters, preferably approximately 40 millimeters to approximately 90 millimeters, more preferably approximately 40 millimeters to approximately 85 millimeters, and more preferably approximately 40 millimeters to approximately 80 millimeters. In other embodiments, the overall length of an aerosol-generating article is approximately 50 millimeters to approximately 95 millimeters, preferably approximately 50 millimeters to approximately 90 millimeters, more preferably approximately 50 millimeters to approximately 85 millimeters, and more preferably approximately 50 millimeters to approximately 80 millimeters. In additional embodiments, the overall length of an aerosol-generating article is approximately 60 millimeters to approximately 95 millimeters, preferably approximately 60 millimeters to approximately 90 millimeters, more preferably approximately 60 millimeters to approximately 85 millimeters, and more preferably approximately 60 millimeters to approximately 80 millimeters. In still additional embodiments, the overall length of an aerosol-generating article is approximately 70 millimeters to approximately 95 millimeters, preferably approximately 70 millimeters to approximately 90 millimeters, more preferably approximately 70 millimeters to approximately 85 millimeters, and more preferably approximately 70 millimeters to approximately 80 millimeters. In one illustrative embodiment, the overall length of the aerosol-generating article is approximately 75 millimeters.

An aerosol generating article according to the present invention may have an external diameter of at least 4 millimeters. Preferably, the aerosol generating article has an external diameter of at least 5 millimeters. More preferably, the aerosol generating article has an external diameter of at least 6 millimeters. Even more preferably, the aerosol generating article has an external diameter of at least 7 millimeters.

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

In some embodiments, the aerosol-generating article has an external diameter of approximately 4 millimeters to approximately 12 millimeters, preferably approximately 5 millimeters to approximately 12 millimeters, more preferably approximately 6 millimeters to approximately 12 millimeters, and even more preferably approximately 7 millimeters to approximately 12 millimeters. In other embodiments, the aerosol-generating article has an external diameter of approximately 4 millimeters to approximately 10 millimeters, preferably approximately 5 millimeters to approximately 10 millimeters, more preferably approximately 6 millimeters to approximately 10 millimeters, and even more preferably approximately 7 millimeters to approximately 10 millimeters. In additional embodiments, the aerosol-generating article has an external diameter of approximately 4 millimeters to approximately 8 millimeters, preferably approximately 5 millimeters to approximately 8 millimeters, more preferably approximately 6 millimeters to approximately 8 millimeters, and even more preferably approximately 7 millimeters to approximately 8 millimeters.

The aerosol generating substrate bar can have a length of between approximately 5 millimeters and approximately 100 mm.

In some embodiments, the aerosol-generating substrate bar preferably has a length of at least approximately 6 millimeters, with a greater preference of at least approximately 7 millimeters. In these embodiments, the aerosol-generating substrate bar may have a length of less than approximately 90 millimeters and preferably has a length of less than approximately 70 millimeters, with a greater preference of less than approximately 65 millimeters, with a greater preference of less than approximately 50 millimeters, with a maximum preference of less than 40 millimeters. In particularly preferred embodiments, the aerosol-generating substrate bar has a length of less than approximately 35 millimeters, with a greater preference of less than 25 millimeters, with a further greater preference of less than approximately 20 millimeters. In one embodiment, the aerosol-generating substrate bar may have a length of approximately 10 millimeters. In a preferred embodiment, the aerosol-generating substrate bar has a length of approximately 12 millimeters. This may be combined with a total length of the aerosol-generating article of approximately 45 millimeters.

In other embodiments, the aerosol-generating rod preferably has a length of at least approximately 10 millimeters, more preferably at least approximately 20 millimeters, and even more preferably at least approximately 30 millimeters. Additionally or alternatively, the aerosol-generating substrate rod preferably has a length of less than or equal to approximately 60 millimeters, more preferably less than or equal to approximately 50 millimeters, and even more preferably less than or equal to approximately 40 millimeters.

In preferred embodiments, the length of the aerosol-generating substrate bar is approximately 10 mm to approximately 60 mm, preferably approximately 20 mm to approximately 60 mm, with a higher preference of approximately 30 mm to approximately 60 mm. In other embodiments, the length of the aerosol-generating substrate bar is approximately 10 mm to approximately 50 mm, preferably approximately 20 mm to approximately 50 mm, with a higher preference of approximately 30 mm to approximately 50 mm. In further embodiments, the length of the aerosol-generating substrate bar is approximately 10 mm to approximately 40 mm, preferably approximately 20 mm to approximately 40 mm, with a higher preference of approximately 40 mm to approximately 60 mm. In one illustrative embodiment, the length of the aerosol-generating substrate bar is approximately 35 mm. This may be combined with a total length of the aerosol-generating article of approximately 75 mm.

Preferably, the aerosol-generating substrate bar has an essentially uniform cross-section along its length. Particularly preferentially, the aerosol-generating substrate bar has an essentially circular cross-section.

In aerosol-generating articles according to the present invention, the density of the aerosol-generating substrate is preferably greater than approximately 300 milligrams per cubic centimeter. As used herein, with reference to the aerosol-generating substrate of the aerosol-generating articles according to the present invention, the term “density” refers to the “apparent density” or “volumetric density” of the substrate, and is equal to the total mass of the aerosol-generating substrate body of a given volume, which is the mass of the homogenized plant material, aerosol former, etc., or the mass of the gel composition of a given volume, divided by said given volume of the aerosol-generating substrate rod.

As such, for example, the density of the aerosol-generating substrate determines the mass of a given volume of homogenized tobacco material and the packing efficiency of a given surface area of homogenized tobacco material. The density of a homogenized tobacco material is normally determined largely by the type of process used to manufacture it. A number of reconstitution processes for producing homogenized tobacco materials are known in the art. These include, but are not limited to: papermaking processes of the type described in, for example, US-A-5,724,998; molding or 'molded sheet' processes described in, for example, US-A-5,724,998; mass reconstitution processes of the type described in, for example, US-A-3,894,544; and extrusion processes of the type described in, for example, GB-A-983,928.

Typically, the densities of homogenized tobacco material produced by extrusion and mass reconstitution processes are higher than those produced by molding processes. The densities of homogenized tobacco materials produced by extrusion processes may be higher than those produced by mass reconstitution processes.

As an example, an aerosol generating substrate density is at least approximately 310 milligrams per cubic centimeter or at least approximately 320 milligrams per cubic centimeter or at least approximately 330 milligrams per cubic centimeter.

In some embodiments, the density of the aerosol-generating substrate is preferably at least approximately 350 milligrams per cubic centimeter. More preferably, the density of the aerosol-generating substrate is at least approximately 400 milligrams per cubic centimeter. Still more preferably, the density of the aerosol-generating substrate is at least approximately 450 milligrams per cubic centimeter. In a particularly preferred embodiment, the density of the aerosol-generating substrate is at least approximately 500 milligrams per cubic centimeter. Preferably, the density of the aerosol-generating substrate is less than or equal to approximately 1000 milligrams per cubic centimeter, more preferably less than or equal to approximately 900 milligrams per cubic centimeter, and still more preferably less than or equal to approximately 800 milligrams per cubic centimeter. As an example, the density of the aerosol-generating substrate can be from approximately 350 milligrams per cubic centimeter to approximately 1000 milligrams per cubic centimeter, preferably from approximately 400 milligrams per cubic centimeter to approximately 1000 milligrams per cubic centimeter, with greater preference from approximately 450 milligrams per cubic centimeter to approximately 1000 milligrams per cubic centimeter, with even greater preference from approximately 500 milligrams per cubic centimeter to approximately 1000 milligrams per cubic centimeter. As another example, an aerosol-generating substrate density can be from approximately 350 milligrams per cubic centimeter to approximately 900 milligrams per cubic centimeter, preferably from approximately 400 milligrams per cubic centimeter to approximately 900 milligrams per cubic centimeter, with further preference from approximately 450 milligrams per cubic centimeter to approximately 900 milligrams per cubic centimeter, with further preference from approximately 500 milligrams per cubic centimeter to approximately 900 milligrams per cubic centimeter. As a further example, the density of the aerosol-generating substrate can be from approximately 350 milligrams per cubic centimeter to approximately 800 milligrams per cubic centimeter, preferably from approximately 400 milligrams per cubic centimeter to approximately 800 milligrams per cubic centimeter, with further preference from approximately 450 milligrams per cubic centimeter to approximately 800 milligrams per cubic centimeter, and with further preference from approximately 500 milligrams per cubic centimeter to approximately 800 milligrams per cubic centimeter.

In other embodiments, the density of the aerosol-generating substrate is at least approximately 600 milligrams per cubic centimeter, preferably at least approximately 700 milligrams per cubic centimeter, more preferably at least approximately 800 milligrams per cubic centimeter, and even more preferably at least approximately 900 milligrams per cubic centimeter. In some particularly preferred embodiments, the density of the aerosol-generating substrate is at least approximately 1 gram per cubic centimeter, preferably at least approximately 1.1 grams per cubic centimeter, more preferably at least approximately 1.2 grams per cubic centimeter, and even more preferably at least approximately 1.3 grams per cubic centimeter. Preferably, the density of the aerosol-generating substrate is less than or equal to approximately 2.0 grams per cubic centimeter, more preferably less than or equal to approximately 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 density of the aerosol-generating substrate is less than or equal to approximately 1.7 grams per cubic centimeter, with greater preference less than or equal to approximately 1.6 grams per cubic centimeter, and with even greater preference less than or equal to approximately 1.5 grams per cubic centimeter.

As an example, the density of the aerosol-generating substrate is preferably from approximately 1 gram per cubic centimeter to approximately 1.7 grams per cubic centimeter, preferably from approximately 1.1 grams per cubic centimeter to approximately 1.7 grams per cubic centimeter, with a higher preference from approximately 1.2 grams per cubic centimeter to approximately 1.7 grams per cubic centimeter, and with an even higher preference from approximately 1.3 grams per cubic centimeter to approximately 1.7 grams per cubic centimeter. As another example, the density of the aerosol-generating substrate is preferably from approximately 1 gram per cubic centimeter to approximately 1.6 grams per cubic centimeter, preferably from approximately 1.1 grams per cubic centimeter to approximately 1.6 grams per cubic centimeter, with a higher preference from approximately 1.2 grams per cubic centimeter to approximately 1.6 grams per cubic centimeter, and with an even higher preference from approximately 1.3 grams per cubic centimeter to approximately 1.6 grams per cubic centimeter. As a further example, an aerosol generating substrate density is preferably from approximately 1 gram per cubic centimeter to approximately 1.5 grams per cubic centimeter, preferably from approximately 1.1 grams per cubic centimeter to approximately 1.5 grams per cubic centimeter, with further preference from approximately 1.2 grams per cubic centimeter to approximately 1.5 grams per cubic centimeter, with further preference from approximately 1.3 grams per cubic centimeter to approximately 1.5 grams per cubic centimeter.

The aerosol generating substrate can be a solid aerosol generating substrate.

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

As used herein, the term “homogenized plant material” encompasses any plant material formed by the agglomeration of plant particles. For example, the sheets or weaves of homogenized tobacco material for the aerosol-generating substrates of the present invention can be formed by agglomerating particles of tobacco material obtained by pulverizing, grinding, or crushing plant material and, optionally, one or more sheets and stems of tobacco leaves. The homogenized plant material can be produced by molding, extrusion, papermaking, 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 invention, the term “sheet” describes a sheet 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 sediments or granules.

Alternatively or additionally, the homogenized plant material may be in the form of a plurality of strands, strips, or fragments. As used herein, the term “strand” describes an elongated element of material having a length that is substantially greater than its width and thickness. The term “strand” should be considered to encompass strips, fragments, and any other homogenized plant material of a similar shape. Strands of homogenized plant material may be formed from a sheet of homogenized plant material, for example, by cutting or shredding, or by other methods, such as extrusion.

In some embodiments, strands may form in situ within the aerosol-generating substrate as a result of splitting or cracking of a sheet of homogenized plant material during the formation of the aerosol-generating substrate, for example, as a result of curling. The strands of homogenized plant material within the aerosol-generating substrate may separate from one another. Alternatively, each strand of homogenized plant material within the aerosol-generating substrate may be at least partially connected to one or more adjacent strands along the length of the strands. For example, adjacent strands may be connected by one or more fibers. This can occur, for example, when the strands have formed due to the splitting of a sheet of homogenized plant material during the production of the aerosol-generating substrate, as described above.

Preferably, the aerosol-generating substrate is in the form of one or more sheets of homogenized plant material. In several embodiments of the invention, the one or more sheets of homogenized plant material may be produced by a molding process. In several embodiments of the invention, the one or more sheets of homogenized plant material may be produced by a papermaking process. The one or more sheets as described herein may each individually have a thickness of between 100 micrometers and 600 micrometers, preferably between 150 micrometers and 300 micrometers, and most preferably between 200 micrometers and 250 micrometers. The individual thickness refers to the thickness of the individual sheet, while the combined thickness refers to the total thickness of all the sheets comprising the aerosol-generating substrate. For example, if the aerosol-generating substrate is formed from two individual sheets, then the combined thickness is either the sum of the thicknesses of the two individual sheets or the thickness measured from the two sheets where the two sheets are stacked on the aerosol-generating substrate.

The one or more sheets as described herein may each individually have a basis weight of between approximately 100 g/m2 and approximately 300 g/m2

The one or more sheets as described herein may each individually have a density of approximately 0.3 g/cm3 to approximately 1.3 g/cm3, and preferably from approximately 0.7 g/cm3 to approximately 1.0 g/cm3.

In the embodiments of the present invention in which the aerosol-generating substrate comprises one or more sheets of homogenized plant material, the sheets are preferably in the form of one or more crinkled sheets. As used herein, the term “crinkled” denotes that the sheet of homogenized plant material is rolled, folded, or otherwise compressed or contracted essentially transversely to the cylindrical axis of a plug or rod.

One or more sheets of homogenized plant material can be folded transversely with respect to its longitudinal axis and enclosed with a wrapper to form a continuous bar or plug.

One or more sheets of homogenized plant material may be curled or similarly advantageously treated. As used herein, the term “curled” denotes a sheet having a plurality of essentially parallel ridges or corrugations. Alternatively or in addition to curling, one or more sheets of homogenized plant material may be embossed, stamped, perforated, or otherwise deformed to provide texture on one or both sides of the sheet.

Preferably, each sheet of homogenized plant material can be curled so that it has a plurality of ridges or corrugations essentially parallel to the cylindrical axis of the stopper. This treatment advantageously facilitates the gathering of the curled sheet of homogenized plant material to form the stopper.

Preferably, one or more sheets of homogenized plant material may be crumpled. It will be noted that the crumpled sheets of homogenized plant material may alternatively or additionally have a plurality of essentially parallel ridges or corrugations arranged at an acute or obtuse angle to the cylindrical axis of the plug. The sheet may be crumpled to such an extent that the integrity of the sheet is interrupted at the plurality of parallel ridges or corrugations, causing separation of the material and resulting in the formation of fragments, strands, or strips of homogenized plant material.

Alternatively, one or more sheets of homogenized plant material may be cut into strands as described above. In such embodiments, the spray-generating substrate comprises a plurality of strands of the homogenized plant material. The strands may be used to form a plug. Typically, the width of such strands is approximately 5 millimeters, or approximately 4 millimeters, or approximately 3 millimeters, or approximately 2 millimeters or less. The length of the strands may be greater than approximately 5 millimeters, from approximately 5 millimeters to approximately 15 millimeters, from approximately 8 millimeters to approximately 12 millimeters, or approximately 12 millimeters.

Ideally, the strands are essentially the same length. Strand length can be determined during the manufacturing process, whereby a bar is cut into shorter plugs, and the strand length corresponds to the plug length. Strands can be brittle, which can lead to breakage, especially during transit. In such cases, the length of some strands may be less than the plug length.

The plurality of strands preferably extends essentially longitudinally along the length of the aerosol-generating substrate, aligned with the longitudinal axis. Preferably, the plurality of strands are therefore aligned essentially parallel to each other.

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

For example, homogenized plant material may comprise from approximately 2.5 percent to approximately 95 percent by weight of plant particles, or from approximately 5 percent to approximately 90 percent by weight of plant particles, or from approximately 10 percent to approximately 80 percent by weight of plant particles, or from approximately 15 percent to approximately 70 percent by weight of plant particles, or from approximately 20 percent to approximately 60 percent by weight of plant particles, or from approximately 30 percent to approximately 50 percent by weight of 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 sheets of homogenized tobacco material for use in such embodiments of the invention may have a tobacco content of at least approximately 40 percent by weight on a dry weight basis, more preferably at least approximately 50 percent by weight on a dry weight basis, more preferably at least approximately 70 percent by weight on a dry weight basis, and most preferably at least approximately 90 percent by weight on a dry weight basis.

With reference to the present invention, the term “tobacco particles” describes particles of any member of plants of the genus Nicotiana. The term “tobacco particles” encompasses ground or powdered tobacco leaf sheet, ground or powdered tobacco leaf stems, tobacco dust, tobacco fines, and other particulate tobacco byproducts formed during the processing, handling, and shipping of tobacco. In a preferred embodiment, the tobacco particles are essentially all derived from tobacco leaf sheet. In contrast, isolated nicotine and nicotine salts are tobacco-derived compounds, but are not considered tobacco particles for the purposes of the invention and are not included in the percentage of particulate plant material.

Tobacco particles can be prepared from one or more varieties of tobacco plants. Any type of tobacco can be used in a blend. Examples of tobacco types that can be used include, but are not limited to, sun-cured tobacco, artificial atmosphere-cured tobacco, Burley tobacco, Maryland tobacco, Oriental tobacco, Virginia tobacco, and other specialty tobaccos.

Artificial atmosphere curing is a method for curing tobacco, particularly used with Virginia tobaccos. During the artificial atmosphere curing process, heated air circulates through densely packed tobacco. In the first stage, the tobacco leaves turn yellow and wilt. In the second stage, the leaf blades dry completely. In the third stage, the leaf stems dry completely.

Burley tobacco plays a significant role in many tobacco blends. It has a distinctive flavor and aroma and also has the ability to absorb large amounts of cover.

Oriental tobacco is a type of tobacco with small leaves and high aromatic qualities. However, oriental tobacco has a milder flavor than, for example, Burley. Therefore, oriental tobacco is generally used in relatively small proportions in tobacco blends.

Kasturi, Madura, and Jatim are subtypes of sun-cured tobacco that can be used. Preferably, Kasturi tobacco and artificially cured tobacco can be used in a mixture to produce the tobacco particles. Consequently, the tobacco particles in the particulate plant material can comprise a mixture of Kasturi tobacco and artificially cured tobacco.

The tobacco particles may have a nicotine content of at least approximately 2.5 percent by weight, on a dry weight basis. More preferably, the tobacco particles may have a nicotine content of at least approximately 3 percent, more preferably at least approximately 3.2 percent, more preferably at least approximately 3.5 percent, with the highest preference at least approximately 4 percent by weight, on a dry weight basis.

In certain other embodiments of the invention, the homogenized plant material comprises tobacco particles in combination with non-tobacco plant flavoring particles. Preferably, the non-tobacco plant flavoring particles are selected from one or more of the following: ginger particles, eucalyptus particles, clove particles, and star anise particles. Preferably, in such embodiments, the homogenized plant material comprises at least approximately 2.5 percent by weight of the non-tobacco plant flavoring particles, on a dry weight basis, with the remainder being tobacco particles. Preferably, the homogenized plant material comprises at least approximately 4 percent by weight of non-tobacco plant flavoring particles, more preferably at least approximately 6 percent by weight of non-tobacco plant flavoring particles, more preferably at least approximately 8 percent by weight of non-tobacco plant flavoring particles, and more preferably at least approximately 10 percent by weight of non-tobacco plant flavoring particles, on a dry weight basis. Preferably, the homogenized plant material comprises up to approximately 20 percent by weight of non-tobacco plant flavoring particles, more preferably up to approximately 18 percent by weight of non-tobacco plant flavoring particles, and more preferably up to approximately 16 percent by weight of non-tobacco plant flavoring particles.

The weight ratio of non-tobacco plant flavoring particles to tobacco particles in the particulate plant material forming the homogenized plant material may vary depending on the desired flavor characteristics and the composition of the aerosol produced from the aerosol-generating substrate during use. Preferably, the homogenized plant material comprises at least a 1:30 weight ratio of non-tobacco plant flavoring particles to tobacco particles, more preferably at least a 1:20 weight ratio of non-tobacco plant flavoring particles to tobacco particles, more preferably at least a 1:10 weight ratio of non-tobacco plant flavoring particles to tobacco particles, and most preferably at least a 1:5 weight ratio of non-tobacco plant flavoring particles to tobacco particles, on a dry weight basis.

Alternatively or additionally to the inclusion of tobacco particles in the homogenized tobacco material of the aerosol-generating substrate according to the invention, the homogenized tobacco material may comprise cannabis particles. The term “cannabis particles” refers to particles from a cannabis plant, such as the species Cannabis sativa, Cannabis indica, and Cannabis ruderalis.

The homogenized plant material preferably comprises no more than 95 percent by weight of the particulate plant material, on a dry weight basis. Therefore, the particulate plant material is typically combined with one or more other components to form the homogenized plant material.

The homogenized plant material may further comprise a binder for altering the mechanical properties of the particulate plant material, wherein the binder is incorporated into the homogenized plant material during manufacturing as described herein. The skilled worker shall be familiar with suitable exogenous binders, which include, but are not limited to: gums such as, for example, guar gum, xanthan gum, gum arabic, and locust bean gum; cellulosic binders such as, for example, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, and ethyl cellulose; polysaccharides such as, for example, starches; organic acids such as alginic acid; salts of conjugate bases of organic acids such as sodium alginate; agar; and pectins; and combinations thereof. Preferably, the binder comprises guar gum.

The binder may be present in an amount of approximately 1 percent to approximately 10 percent by weight, based on the dry weight of the homogenized plant material, preferably in an amount of approximately 2 percent to approximately 5 percent by weight, based on the dry weight of the homogenized plant material.

Alternatively or additionally, the homogenized plant material may further comprise one or more lipids to facilitate the diffusivity of volatile components (e.g., aerosol formers, gingerols, and nicotine), wherein the lipid is incorporated into the homogenized plant material during manufacturing 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, husk, sunflower wax, sunflower oil, rice bran, and Revel A; and combinations thereof.

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

Alternatively or additionally, the homogenized plant material may further comprise fibers to alter the mechanical properties of the homogenized plant material, wherein the fibers are incorporated into 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 material, including, but not limited to: cellulosic fibers; softwood fibers; hardwood fibers; jute fibers and combinations thereof. Exogenous fibers derived from tobacco and/or ginger may also be added. No fiber added to the homogenized plant material is 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: mechanical defibration; refining; chemical defibration; bleaching; Defibrated with sulfate; and combinations thereof. A fiber typically has a length greater than its width.

Suitable fibers typically have lengths greater than 400 micrometers and less than or equal to 4 millimeters, preferably within the range of 0.7 millimeters to 4 millimeters. Preferably, the fibers are present in an amount of approximately 2 percent to approximately 15 percent by weight, with the highest preference being approximately 4 percent by weight, based on the dry weight of the substrate.

Alternatively or additionally, the homogenized plant material may further comprise one or more aerosol formers. Upon volatilization, an aerosol former can carry other vaporized compounds released from the aerosol-generating substrate upon heating, such as nicotine and flavorings, into an aerosol. Suitable aerosol formers for inclusion in the homogenized plant material are known in the art and include, but are not limited to: polyhydric alcohols, such as triethylene glycol, propylene glycol, 1,3-butanediol, and glycerol; esters of polyhydric alcohols, such as mono-, di-, or triacetate of glycerol; and aliphatic esters of mono-, di-, or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate.

Homogenized plant material may have an aerosol former content of between approximately 5 percent and approximately 30 percent by weight on a dry weight basis, such as between approximately 10 percent and approximately 25 percent by weight on a dry weight basis, or between approximately 15 percent and approximately 20 percent by weight on a dry weight basis.

For example, if the substrate is intended for use in an aerosol-generating article for an electrically operated aerosol-generating system having a heating element, it may preferably include an aerosol former content of between approximately 10 percent and approximately 30 percent by weight on a dry weight basis. If the substrate is intended for use in an aerosol-generating article for 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 approximately 30 percent to approximately 45 percent by weight. This relatively high level of aerosol former is particularly suitable for aerosol-generating substrates intended to be heated to a temperature below 275 degrees Celsius. In such embodiments, the homogenized plant material also preferably comprises between approximately 2 percent and approximately 10 percent by weight of cellulose ether, on a dry weight basis, and between approximately 5 percent and approximately 50 percent by weight of additional cellulose, on a dry weight basis. The use of the combination of cellulose ether and additional cellulose has been found to provide a particularly effective aerosol supply when used in an aerosol-generating substrate having an aerosol former content of between 30 percent and 45 percent by weight.

Suitable cellulose ethers include, but are not limited to, methyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, ethylhydroxyethyl cellulose, and carboxymethyl cellulose (CMC). In particularly preferred embodiments, 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 the non-tobacco plant particles or tobacco particles provided in the homogenized plant material. Therefore, the additional cellulose is incorporated into the homogenized plant material in addition to the non-tobacco plant material or tobacco 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 will typically be derived from a plant different from 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 organoleptic characteristics of the aerosol generated from the aerosol-generating substrate. For example, the additional cellulose is preferably a tasteless and odorless material.

Additional cellulose may comprise cellulose powder, cellulosic fibers, or combinations thereof.

The aerosol former can act as a wetting agent on the aerosol-generating substrate.

In certain preferred embodiments of the present invention, the aerosol-generating substrate comprises a gel composition that includes an alkaloid compound, a cannabinoid compound, or both an alkaloid and a cannabinoid compound. In particularly preferred embodiments, the aerosol-generating substrate comprises a gel composition that includes nicotine.

Preferably, the gel composition comprises an alkaloid compound, a cannabinoid compound, or both an alkaloid and a cannabinoid 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, with the alkaloid or cannabinoid dispersed in the glycerol. Preferably, the gel composition is a stable gel phase.

Advantageously, a stable gel composition comprising nicotine provides a predictable shape after storage or transport from manufacturing to the consumer. The stable gel composition comprising nicotine essentially maintains its shape. The stable gel composition comprising nicotine essentially does not release a liquid phase after storage or transport from manufacturing to the consumer. The stable gel composition comprising nicotine can provide a simple consumable design. This consumable does not necessarily have to be designed to contain a liquid, thus allowing for a wider range of container materials and constructions.

The gel composition described herein can be combined with an aerosol-generating device to deliver a nicotine aerosol to the lungs at inhalation rates or airflows that are within the range of conventional smoking rates or airflows. The aerosol-generating device can continuously heat the gel composition. A consumer can take multiple inhalations or “puffs,” each “puff” delivering a quantity of nicotine aerosol. The gel composition may be capable of delivering a high-nicotine/low total particulate matter (TPM) aerosol to a consumer when heated, preferably continuously. The phrase “stable gel phase” or “stable gel” refers to a gel that essentially maintains its shape and mass when exposed to a variety of environmental conditions. The stable gel may not essentially release (sweeten) or absorb water when exposed to standard temperature and pressure while relative humidity varies from approximately 10 percent to approximately 60 percent. For example, stable gel can essentially maintain its shape and mass when exposed to standard temperature and pressure while varying relative humidity from about 10 percent to about 60 percent.

The gel composition includes an alkaloid compound, a cannabinoid compound, or both. The gel composition may include one or more alkaloids. The gel composition may include one or more cannabinoids. The gel composition may include a combination of one or more alkaloids and one or more cannabinoids.

The term “alkaloid compound” refers to any of a class of naturally occurring organic compounds that contain one or more basic nitrogen atoms. Generally, an alkaloid contains at least one nitrogen atom in an amine-type structure. This or another nitrogen atom in the alkaloid compound molecule can be active as a base in acid-base reactions. Most alkaloid compounds have one or more of their nitrogen atoms as part of a cyclic system, such as a heterocyclic ring. In nature, alkaloid compounds are found primarily in plants and are especially common in certain families of flowering plants. However, some alkaloid compounds are found in animal species and fungi. In this description, the term “alkaloid compound” refers to both naturally occurring and synthetically produced alkaloid compounds.

The gel composition may preferably include an alkaloid compound selected from the group consisting of nicotine, anatabine, and combinations thereof.

Preferably, the gel composition includes nicotine.

The term “nicotine” refers to nicotine and nicotine derivatives such as freebase nicotine, nicotine salts, and the like.

The term “cannabinoid compound” refers to any of a class of naturally occurring compounds found in parts of the cannabis plant, specifically the species Cannabis sativa, Cannabis indica, and Cannabis ruderalis. Cannabinoid compounds are especially concentrated in the female flower heads. Naturally occurring cannabinoid compounds in the cannabis plant include cannabidiol (CBD) and tetrahydrocannabinol (THC). In this description, the term “cannabinoid compounds” is used to describe both naturally occurring and synthetically produced cannabinoid compounds.

The gel may include a cannabinoid compound selected from the group consisting of cannabidiol (CBD), tetrahydrocannabinol (THC), tetrahydrocannabinolic acid (THCA), cannabidiolic acid (CBDA), cannabinol (CBN), cannabigerol (CBG), cannabichromene (CBC), cannabicyclol (CBL), cannabivarin (CBV), tetrahydrocannabivarin (THCV), cannabidivarin (CBDV), cannabichromevarin (CBCV), cannabigerovarin (CBGV), cannabigerol monomethyl ether (CBGM), cannabielsoin (CBE), cannabicitran (CBT), and combinations thereof.

The gel composition may preferably include a cannabinoid compound selected from the group consisting of cannabidiol (CBD), THC (tetrahydrocannabinol) and their combinations.

The gel may preferably include cannabidiol (CBD).

The gel's composition may include nicotine and cannabidiol (CBD).

The gel's composition may include nicotine, cannabidiol (CBD), and THC (tetrahydrocannabinol).

The gel composition preferably includes approximately 0.5 percent by weight to approximately 10 percent by weight of an alkaloid compound, or approximately 0.5 percent by weight to approximately 10 percent by weight of a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound in a total amount of approximately 0.5 percent by weight to approximately 10 percent by weight. The gel composition may also include approximately 0.5 percent by weight to approximately 5 percent by weight of an alkaloid compound, or approximately 0.5 percent by weight to approximately 5 percent by weight of a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound in a total amount of approximately 0.5 percent by weight to approximately 5 percent by weight. Preferably, the gel composition includes approximately 1 percent by weight to approximately 3 percent by weight of an alkaloid compound, or approximately 1 percent by weight to approximately 3 percent by weight of a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound in a total amount of approximately 1 percent by weight to approximately 3 percent by weight. The gel composition may preferably include approximately 1.5 percent by weight to approximately 2.5 percent by weight of an alkaloid compound, or approximately 1.5 percent by weight to approximately 2.5 percent by weight of a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound in a total amount of approximately 1.5 percent by weight to approximately 2.5 percent by weight. The gel composition may preferably include approximately 2 percent by weight of an alkaloid compound, or approximately 2 percent by weight of a cannabinoid compound, or both an alkaloid and a cannabinoid compound in a total amount of approximately 2 percent by weight. The alkaloid component of the gel formulation may be the most volatile component of the gel formulation. In some cases, water may be the most volatile component of the gel formulation, and the alkaloid component of the gel formulation may be the second most volatile component. The cannabinoid component of the gel formulation may be the most volatile component of the gel formulation. In some cases, water may be the most volatile component of the gel formulation, and the alkaloid component of the gel formulation may be the second most volatile component.

Preferably, nicotine is included in the gel compositions. Nicotine may be added to the composition in freebase or salt form. The gel composition includes approximately 0.5% to approximately 10% by weight of nicotine, or approximately 0.5% to approximately 5% by weight of nicotine. Preferably, the gel composition includes approximately 1% to approximately 3% by weight of nicotine, or approximately 1.5% to approximately 2.5% by weight of nicotine, or approximately 2% by weight of nicotine. The nicotine component of the gel formulation may be the most volatile component. In some cases, water may be the most volatile component of the gel formulation, and the nicotine component may be the second most volatile component.

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

The gel composition may consist primarily of an aerosol former. The gel composition may consist of a mixture of water and the aerosol former, where the aerosol former constitutes a majority (by weight) of the gel composition. The aerosol former may constitute at least approximately 50 percent by weight of the gel composition. The aerosol former may constitute at least approximately 60 percent by weight, or at least approximately 65 percent by weight, or at least approximately 70 percent by weight of the gel composition. The aerosol former may constitute approximately 70 percent by weight to approximately 80 percent by weight of the gel composition. The aerosol former may constitute approximately 70 percent by weight to approximately 75 percent by weight of the gel composition.

The gel composition may consist primarily of glycerol. The gel composition may consist of a mixture of water and glycerol, where glycerol constitutes a majority (by weight) of the gel composition. Glycerol may constitute at least approximately 50 percent by weight of the gel composition. Glycerol may constitute at least approximately 60 percent by weight, or at least approximately 65 percent by weight, or at least approximately 70 percent by weight of the gel composition. Glycerol may constitute approximately 70 percent by weight to approximately 80 percent by weight of the gel composition. Glycerol may constitute approximately 70 percent by weight to approximately 75 percent 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 agents ranging from approximately 0.4 percent by weight to approximately 10 percent by weight. More preferably, the composition includes gelling agents ranging from approximately 0.5 percent by weight to approximately 8 percent by weight. More preferably, the composition includes gelling agents ranging from approximately 1 percent by weight to approximately 6 percent by weight. More preferably, the composition includes gelling agents ranging from approximately 2 percent by weight to approximately 4 percent by weight. More preferably, the composition includes gelling agents ranging from approximately 2 percent by weight to approximately 3 percent by weight.

The term “gelling agent” refers to a compound that, when added homogeneously to a 50 wt/50 wt water/glycerol mixture in an amount of approximately 0.3 wt, forms a solid medium or support matrix leading to a gel. Gelling agents include, but are not limited to, hydrogen-linked crosslinking gelling agents and ionic crosslinking gelling agents.

The gelling agent may include one or more biopolymers. Biopolymers may be formed from polysaccharides. Biopolymers include, for example, gellan gums (native, low-acyl gellan gum, high-acyl gellan gum, low-acyl gellan gum being preferred), xanthan gum, alginates (alginic acid), agar, guar gum, and similar compounds. The composition may preferably include xanthan gum. The composition may include two biopolymers. The composition may include three biopolymers. The composition may include the two biopolymers in essentially equal weights. The composition may include the three biopolymers in essentially equal weights.

Preferably, the gel composition comprises at least approximately 0.2 percent by weight of a hydrogen-bonded crosslinking gelling agent. Alternatively or additionally, the gel composition preferably comprises at least approximately 0.2 percent by weight of an ionic crosslinking gelling agent. Most preferably, the gel composition comprises at least approximately 0.2 percent by weight of a hydrogen-bonded crosslinking gelling agent and at least approximately 0.2 percent by weight of an ionic crosslinking gelling agent. The gel composition may comprise approximately 0.5 percent by weight to approximately 3 percent by weight of a hydrogen-bonded crosslinking gelling agent and approximately 0.5 percent by weight to approximately 3 percent by weight of an ionic crosslinking gelling agent, or approximately 1 percent by weight to approximately 2 percent by weight of a hydrogen-bonded crosslinking gelling agent and approximately 1 percent by weight to approximately 2 percent by weight of an ionic crosslinking gelling agent. The hydrogen-bonded crosslinking gelling agent and the ionic crosslinking gelling agent may be present in the gel composition in essentially equal amounts by weight.

The term “hydrogen-crosslinking gelling agent” refers to a gelling agent that forms non-covalent or physical crosslinks through hydrogen bonding. Hydrogen bonding is a type of electrostatic dipole-dipole attraction between molecules, not a covalent bond to a hydrogen atom. It results from the attractive force between a hydrogen atom covalently bonded to a highly electronegative atom, such as an N, O, or F atom, and another highly electronegative atom.

The hydrogen-bonded crosslinking gelling agent may include one or more of a galactomannan, gelatin, agarose, konjac gum, or agar. The hydrogen-bonded crosslinking gelling agent may preferably include agar. The gel composition preferably includes the hydrogen-bonded crosslinking gelling agent in a range of approximately 0.3 percent by weight to approximately 5 percent by weight. Preferably, the composition includes the hydrogen-bonded crosslinking gelling agent in a range of approximately 0.5 percent by weight to approximately 3 percent by weight. Preferably, the composition includes the hydrogen-bonded crosslinking gelling agent in a range of approximately 1 percent by weight to approximately 2 percent by weight.

The gel composition may include galactomannan in a range of approximately 0.2 percent by weight to approximately 5 percent by weight. Preferably, the galactomannan may be in a range of approximately 0.5 percent by weight to approximately 3 percent by weight. Preferably, the galactomannan may be in a range of approximately 0.5 percent by weight to approximately 2 percent by weight. Preferably, the galactomannan may be in a range of approximately 1 percent by weight to approximately 2 percent by weight.

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

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

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

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

The term “ionic crosslinking gelling agent” refers to a gelling agent that forms non-covalent or physical crosslinks through ionic bonding. Ionic crosslinking involves the association of polymer chains through non-covalent interactions. A crosslinked network forms when multivalent molecules with opposite charges are electrostatically attracted to each other, resulting in a crosslinked polymer network.

The ionic crosslinking gelling agent may include low-acyl gellan, pectin, kappa carrageenan, iota carrageenan, or alginate. The ionic crosslinking gelling agent may preferably include low-acyl gellan.

The gel composition may include the ionic crosslinking gelling agent in a range of approximately 0.3 percent by weight to approximately 5 percent by weight. Preferably, the composition includes the ionic crosslinking gelling agent in a range of approximately 0.5 percent by weight to approximately 3 percent by weight. Preferably, the composition includes the ionic crosslinking gelling agent in a range of approximately 1 percent by weight to approximately 2 percent by weight.

The gel composition may include low-acyl gellan in a range of approximately 0.2 percent by weight to approximately 5 percent by weight. Preferably, the low-acyl gellan may be in a range of approximately 0.5 percent by weight to approximately 3 percent by weight. Preferably, the low-acyl gellan may be in a range of approximately 0.5 percent by weight to approximately 2 percent by weight. Preferably, the low-acyl gellan may be in a range of approximately 1 percent by weight to approximately 2 percent by weight.

The gel composition may include pectin in a range of approximately 0.2 percent by weight to approximately 5 percent by weight. Preferably, the pectin may be in a range of approximately 0.5 percent by weight to approximately 3 percent by weight. Preferably, the pectin may be in a range of approximately 0.5 percent by weight to approximately 2 percent by weight. Preferably, the pectin may be in a range of approximately 1 percent by weight to approximately 2 percent by weight.

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

The gel composition may include iota carrageenan in a range of approximately 0.2 percent by weight to approximately 5 percent by weight. Preferably, the iota carrageenan may be in a range of approximately 0.5 percent by weight to approximately 3 percent by weight. Preferably, the iota carrageenan may be in a range of approximately 0.5 percent by weight to approximately 2 percent by weight. Preferably, the iota carrageenan may be in a range of approximately 1 percent by weight to approximately 2 percent by weight.

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

The gel composition may include the hydrogen-bonded crosslinking gelling agent and the ionic crosslinking gelling agent in a ratio of approximately 3:1 to approximately 1:3. Preferably, the gel composition may include the hydrogen-bonded crosslinking gelling agent and the ionic crosslinking gelling agent in a ratio of approximately 2:1 to approximately 1:2. Preferably, the gel composition may include the hydrogen-bonded crosslinking gelling agent and the ionic crosslinking gelling agent in a ratio of approximately 1:1.

The gel composition may also include a viscosifying agent. The viscosifying agent, combined with the hydrogen-linked gelling agent and the ionic-linked gelling agent, appears to remarkably support the solid medium and maintain the gel composition even when the gel composition comprises a high level of glycerol.

The term “viscosity agent” refers to a compound that, when added homogeneously to a mixture of 25 °C glycerol, 50 wt% water/50 wt% water, in an amount of 0.3 wt%, increases the viscosity without leading to gel formation, and the mixture remains fluid. Preferably, the viscosifying agent refers to a compound that, when added homogeneously to a mixture of 25 °C glycerol, 50 wt% water/50 wt% water, in an amount of 0.3 wt%, increases the viscosity to at least 50 cP, preferably at least 200 cP, preferably at least 500 cP, preferably at least 1000 cP at a shear rate of 0.1 s⁻¹, without leading to gel formation, and the mixture remains fluid. Preferably, the viscosifying agent refers to a compound that, when added homogeneously to a 25°C 50 wt. water/50 wt. glycerol mixture in an amount of 0.3 wt., increases the viscosity at least 2 times, or at least 5 times, or at least 10 times, or at least 100 times greater than before the addition, at a shear rate of 0.1 s-1, without leading to the formation of a gel, the mixture remains or stays in the fluid.

The viscosity values quoted in this description can be measured using a Brookfield RVT viscometer that rotates a disc-type RV#2 spindle at 25 °C at a speed of 6 revolutions per minute (rpm).

The gel composition preferably includes the viscosifying agent in a range of approximately 0.2 percent by weight to approximately 5 percent by weight. Preferably, the composition includes the viscosifying agent in a range of approximately 0.5 percent by weight to approximately 3 percent by weight. Preferably, the composition includes the viscosifying agent in a range of approximately 0.5 percent by weight to approximately 2 percent by weight. Preferably, the composition includes the viscosifying agent in a range of approximately 1 percent by weight to approximately 2 percent by weight.

The thickening agent may include one or more of xanthan gum, carboxymethylcellulose, microcrystalline cellulose, methylcellulose, gum arabic, guar gum, lambda carrageenan, or starch. The thickening agent may preferably include xanthan gum.

The gel composition may include xanthan gum in a range of approximately 0.2 percent by weight to approximately 5 percent by weight. Preferably, the xanthan gum may be in a range of approximately 0.5 percent by weight to approximately 3 percent by weight. Preferably, the xanthan gum may be in a range of approximately 0.5 percent by weight to approximately 2 percent by weight. Preferably, the xanthan gum may be in a range of approximately 1 percent by weight to approximately 2 percent by weight.

The gel composition may include carboxymethylcellulose in a range of approximately 0.2 percent by weight to approximately 5 percent by weight. Preferably, the carboxymethylcellulose may be in a range of approximately 0.5 percent by weight to approximately 3 percent by weight. Preferably, the carboxymethylcellulose may be in a range of approximately 0.5 percent by weight to approximately 2 percent by weight. Preferably, the carboxymethylcellulose may be in a range of approximately 1 percent by weight to approximately 2 percent by weight.

The gel composition may include microcrystalline cellulose in a range of approximately 0.2 percent by weight to approximately 5 percent by weight. Preferably, the microcrystalline cellulose may be in a range of approximately 0.5 percent by weight to approximately 3 percent by weight. Preferably, the microcrystalline cellulose may be in a range of approximately 0.5 percent by weight to approximately 2 percent by weight. Preferably, the microcrystalline cellulose may be in a range of approximately 1 percent by weight to approximately 2 percent by weight.

The gel composition may include methylcellulose in a range of approximately 0.2 percent by weight to approximately 5 percent by weight. Preferably, the methylcellulose may be in a range of approximately 0.5 percent by weight to approximately 3 percent by weight. Preferably, the methylcellulose may be in a range of approximately 0.5 percent by weight to approximately 2 percent by weight. Preferably, the methylcellulose may be in a range of approximately 1 percent by weight to approximately 2 percent by weight.

The gel composition may include gum arabic in a range of approximately 0.2 percent by weight to approximately 5 percent by weight. Preferably, the gum arabic may be in a range of approximately 0.5 percent by weight to approximately 3 percent by weight. Preferably, the gum arabic may be in a range of approximately 0.5 percent by weight to approximately 2 percent by weight. Preferably, the gum arabic may be in a range of approximately 1 percent by weight to approximately 2 percent by weight.

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

The gel composition may include lambda-carrageenan in a range of approximately 0.2 percent by weight to approximately 5 percent by weight. Preferably, the lambda-carrageenan may be in a range of approximately 0.5 percent by weight to approximately 3 percent by weight. Preferably, the lambda-carrageenan may be in a range of approximately 0.5 percent by weight to approximately 2 percent by weight. Preferably, the lambda-carrageenan may be in a range of approximately 1 percent by weight to approximately 2 percent by weight.

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

The gel composition may also include a divalent cation. Preferably, the divalent cation includes calcium ions, such as calcium lactate in solution. Divalent cations (such as calcium ions) can aid in gel formation in compositions that include gelling agents such as an ionic crosslinking gelling agent, for example. The ionic effect can assist in gel formation. The divalent cation may be present in the gel composition in a range of approximately 0.1 to approximately 1 percent by weight, or approximately 0.5 percent by weight.

The gel composition may also include an acid. The acid may comprise a carboxylic acid. The carboxylic acid may include a ketone group. Preferably, the carboxylic acid may include a ketone group having fewer than approximately 10 carbon atoms, or fewer than approximately 6 carbon atoms, or fewer than approximately 4 carbon atoms, such as levulinic acid or lactic acid. Preferably, this carboxylic acid has three carbon atoms (such as lactic acid). Lactic acid significantly improves the stability of the gel composition even compared to similar carboxylic acids. The carboxylic acid may aid in gel formation. The carboxylic acid may reduce the variation in the concentration of the alkaloid compound, or the concentration of the cannabinoid compound, or both the concentrations of the alkaloid and cannabinoid compounds within the gel composition during storage. The carboxylic acid may reduce the variation in the concentration of nicotine within the gel composition during storage.

The gel composition may include a carboxylic acid in a range of approximately 0.1 percent by weight to approximately 5 percent by weight. Preferably, the carboxylic acid may be in a range of approximately 0.5 percent by weight to approximately 3 percent by weight. Preferably, the carboxylic acid may be in a range of approximately 0.5 percent by weight to approximately 2 percent by weight. Preferably, the carboxylic acid may be in a range of approximately 1 percent by weight to approximately 2 percent by weight.

The gel composition may include lactic acid in a range of approximately 0.1 percent by weight to approximately 5 percent by weight. Preferably, the lactic acid may be in a range of approximately 0.5 percent by weight to approximately 3 percent by weight. Preferably, the lactic acid may be in a range of approximately 0.5 percent by weight to approximately 2 percent by weight. Preferably, the lactic acid may be in a range of approximately 1 percent by weight to approximately 2 percent by weight.

The gel composition may include levulinic acid in a range of approximately 0.1 percent by weight to approximately 5 percent by weight. Preferably, the levulinic acid may be in a range of approximately 0.5 percent by weight to approximately 3 percent by weight. Preferably, the levulinic acid may be in a range of approximately 0.5 percent by weight to approximately 2 percent by weight. Preferably, the levulinic acid may be in a range of approximately 1 percent by weight to approximately 2 percent by weight.

The gel composition preferably includes some water. The gel composition is more stable when it includes some water. Preferably, the gel composition comprises at least approximately 1 percent by weight, or at least approximately 2 percent by weight, or at least approximately 5 percent by weight of water. Preferably, the gel composition comprises at least approximately 10 percent by weight or at least approximately 15 percent by weight of water.

Preferably, the gel composition comprises from approximately 8 percent to approximately 32 percent by weight of water. Preferably, the gel composition comprises from approximately 15 to 25 percent by weight of water. Preferably, the gel composition comprises from approximately 18 to 22 percent by weight of water. Preferably, the gel composition comprises approximately 20 percent by weight of water.

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

Preferably, the aerosol-generating substrate comprises a porous medium loaded with the gel composition. The advantage of a porous medium loaded with the gel composition is that the gel composition is retained within the porous medium, which can facilitate the manufacturing, storage, or transport of the gel composition. It can also help maintain the desired shape of the gel composition, especially during manufacturing, transport, or use.

The porous medium can be any suitable porous material capable of containing or retaining the gel composition. Ideally, the porous medium should allow the gel composition to move within it. In specific embodiments, the porous medium comprises natural, synthetic, or semi-synthetic materials, or combinations thereof. In certain embodiments, the porous medium comprises sheet-like material, foam, or fibers, for example, loose fibers; or a combination thereof. In specific embodiments, the porous medium comprises a woven, non-woven, or extruded material, or combinations thereof. Preferably, the porous medium comprises cotton, paper, viscose, PLA, or cellulose acetate, or combinations thereof. Preferably, the porous medium comprises a sheet-like material, for example, cotton or cellulose acetate. In a particularly preferred embodiment, the porous medium comprises a sheet made of cotton fibers.

The porous medium used in the present invention can be curled or crushed. In preferred embodiments, the porous medium is curled. In alternative embodiments, the porous medium comprises crushed porous medium. The curling or crushing process can be performed before or after loading with the gel composition.

The crimped sheet material has the benefit of improving its structure, allowing passages through it. Passages through the crimped sheet material facilitate gel loading, gel retention, and fluid flow. Therefore, using crimped sheet material as a porous medium has its advantages.

The grinding gives a high surface area to volume ratio to the medium, so it is able to absorb gel easily.

In specific embodiments, the sheet material is a composite material. Preferably, the sheet material is porous. The sheet material can aid in the fabrication of the tubular element comprising a gel. The sheet material can aid in the introduction of an active agent into the tubular element comprising a gel. The sheet material can aid in stabilizing the structure of the tubular element comprising a gel. The sheet material can aid in the transport or storage of the gel. The use of a sheet material allows, or aids in, adding structure to the porous medium, for example, by curling the sheet material.

The porous medium can be a thread. The thread can be made of, for example, cotton, paper, or acetate tow. The thread can also be filled with gel, like any other porous medium. One advantage of using a thread as a porous medium is that it can help simplify manufacturing.

The thread can be gel-loaded by any known means. The thread can simply be coated with gel, or it can be impregnated with gel. In manufacturing, threads can be impregnated with gel and stored ready for use in the assembly of a tubular component.

The porous medium, filled with the gel composition, is preferably provided within a tubular element that forms part of the aerosol-generating article. The term “tubular element” is used to describe a component suitable for use in an aerosol-generating article. Ideally, the tubular element is longer than it is wide, but this is not necessary, as it may be part of a multi-component element, which ideally will be longer than it is wide. Typically, the tubular element is cylindrical, but this is not mandatory. For example, the tubular element may have an oval, polygonal, triangular, rectangular, or random cross-section.

The tubular element preferably comprises a first longitudinal step. The tubular element is preferably formed from a sheath that defines the first longitudinal step. The sheath is preferably a water-resistant sheath. This water-resistant property of the sheath can be achieved by using a water-resistant material or by treating the sheath material. It can be achieved by treating one or both sides of the sheath. Being water-resistant would help prevent loss of structure, hardness, or rigidity. It can also help prevent leakage of gel or liquid, especially when using gels with a fluid structure.

The aerosol-generating substrate rod further comprises a susceptor element disposed within the aerosol-generating substrate. In practice, in some embodiments of the aerosol-generating article according to the present invention, a susceptor element, such as an elongated susceptor, is essentially disposed within the aerosol-generating substrate rod such that the susceptor element is in thermal contact with the aerosol-generating substrate.

As used in this description, 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 it to heat up. Because the elongated susceptor is 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 to describe the susceptor, the term “elongated” means that the susceptor has a length dimension greater than its width or thickness dimension—for example, greater than twice its width or thickness dimension.

The elongated susceptor is preferably arranged essentially longitudinally within the bar. This means that the length dimension of the elongated susceptor is arranged to be approximately parallel to the longitudinal direction of the bar, for example, within plus or minus 10 degrees parallel to the longitudinal direction of the bar. In preferred embodiments, the elongated susceptor may be positioned radially centrally within the bar and extends along the longitudinal axis of the bar.

Preferably, the elongated susceptor extends to a downstream end of the aerosol-generating article's bar. In some embodiments, the susceptor may extend to an upstream end of the aerosol-generating article's bar. In particularly preferred embodiments, the susceptor is essentially the same length as the aerosol-generating substrate bar and extends from the upstream end of the bar to the downstream end of the bar.

The susceptor is preferably in the form of a pin, rod, strip, or sheet.

The susceptor preferably has a length of approximately 5 millimeters to approximately 15 millimeters, for example, from approximately 6 millimeters to approximately 12 millimeters, or from approximately 8 millimeters to approximately 10 millimeters.

A ratio between the length of the susceptor and the total length of the aerosol-generating article can be from approximately 0.2 to approximately 0.35.

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

In a particularly preferred embodiment, the ratio of the susceptor length to the total length of the aerosol-generating article is approximately 0.27.

The susceptor preferably has a width of approximately 1 millimeter to approximately 5 millimeters. The susceptor can generally have a thickness of approximately 0.01 millimeters to approximately 2 millimeters, for example, from approximately 0.5 millimeters to approximately 2 millimeters. In some embodiments, the susceptor preferably has a thickness of approximately 10 micrometers to approximately 500 micrometers, and more preferably from approximately 10 micrometers to approximately 100 micrometers.

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

If the susceptor is in the form of a strip or sheet, the strip or sheet preferably has a rectangular shape with a width of preferably approximately 2 millimeters to approximately 8 millimeters, more preferably approximately 3 millimeters to approximately 5 millimeters. For example, a susceptor in the form of a sheet strip may have a width of approximately 4 millimeters.

If the susceptor is in the form of a strip or sheet, the strip or sheet preferably has a rectangular shape and a thickness of approximately 0.03 millimeters to approximately 0.15 millimeters, more preferably from approximately 0.05 millimeters to approximately 0.09 millimeters. By way of example, a susceptor in the form of a sheet strip may have a thickness of approximately 0.07 millimeters.

In a preferred embodiment, the elongated susceptor element provided in the form of a strip or sheet, preferably has a rectangular shape, and has a thickness of approximately 55 micrometers to approximately 65 micrometers.

Most preferably, the elongated susceptor has a thickness of approximately 57 micrometers to approximately 63 micrometers. Even more preferably, the elongated susceptor has a thickness of approximately 58 micrometers to approximately 62 micrometers. In a particularly preferred embodiment, the elongated susceptor has a thickness of approximately 60 micrometers.

Without wishing to limit themselves to theory, the inventors consider that, overall, the selection of a given thickness for the susceptor is also affected by the constraints imposed by the selected length and width of the susceptor, as well as by the constraints imposed by the geometry and dimensions of the aerosol-generating substrate bar. By way of example, the length of the susceptor is preferably selected to match the length of the aerosol-generating substrate bar. The width of the susceptor should preferably be chosen to prevent displacement of the susceptor within the substrate, while also allowing for easy insertion during manufacturing.

The inventors have discovered that in an aerosol-generating article where a susceptor of a thickness within the range described above is provided to inductively supply heat during use, it is advantageously possible to generate and distribute heat throughout the aerosol-generating substrate in a particularly effective and efficient manner. Not wishing to be limited to theory, the inventors believe this is because such a susceptor is adapted to provide optimal heat generation and heat transfer, by virtue of the susceptor's surface area and inductive energy. Conversely, a thinner susceptor may be too easily deformed and may not maintain the desired shape and orientation within the aerosol-generating substrate rod during manufacture of the aerosol-generating article, which may result in less homogeneous and less precise heat distribution during use. At the same time, a thicker susceptor can be more difficult to cut lengthwise with precision and consistency, and this can also affect the accuracy with which the susceptor can be provided in longitudinal alignment within the aerosol-generating substrate bar, thus potentially affecting the homogeneity of the heat distribution within the bar. These advantageous effects are especially noticeable when the susceptor extends to the downstream end of the aerosol-generating article bar. This is thought to be because the downstream resistance to suction (RTD) of the susceptor can be minimized, as there is no aerosol-generating substrate within the bar at a location downstream of the susceptor that can contribute to the RTD. This is achieved particularly effectively in configurations where the aerosol-generating article comprises a downstream section with a hollow intermediate section. Such a hollow intermediate section does not contribute significantly to the overall RTD of the aerosol-generating article and does not come into direct contact with a downstream end of the susceptor.

Without wishing to limit themselves to theory, the inventors consider that the downstream portion of the aerosol-generating substrate bar can act, to some extent, as a filter with respect to more upstream portions of the aerosol-generating substrate bar. Therefore, the inventors believe it is advantageous to be able to heat the downstream portion of the aerosol-generating substrate bar homogeneously as well, so that it actively participates in the release of volatile aerosol species and contributes to the overall generation and delivery of aerosol. Any potential filtering effect that might hinder aerosol delivery to the consumer would be positively counteracted by the release of volatile aerosol species along the entire length of the aerosol-generating substrate.

Preferably, the elongated susceptor has a length equal to or less than that of the aerosol-generating substrate. Preferably, the elongated susceptor has the same length as the aerosol-generating substrate.

The susceptor can be made of any material that can be induction-heated to a temperature sufficient to generate an aerosol from the aerosol-generating substrate. Susceptors are preferably made of a metal or carbon.

A preferred susceptor may comprise or consist of a ferromagnetic material, for example, a ferromagnetic alloy, ferritic iron, or ferromagnetic or stainless steel. A suitable susceptor may be made of, or comprise, aluminum. Preferred susceptors may be formed from 400 series stainless steels, for example, grade 410, grade 420, or grade 430 stainless steel. Different materials will dissipate different amounts of energy when placed within electromagnetic fields that have similar values of frequency and field strength.

Therefore, susceptor parameters such as material type, length, width, and thickness can all be altered to provide a desired energy dissipation within a known electromagnetic field. Preferred susceptors can be heated to temperatures exceeding 250 degrees Celsius.

Suitable susceptors may comprise a non-metallic core with a metal layer disposed on the non-metallic core, for example, metallic tracks formed on the surface of a ceramic core. A susceptor may have an outer protective layer, for example, a ceramic or glass protective layer encapsulating the susceptor. The susceptor may comprise a protective coating formed from glass, ceramic, or an 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, 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 comprising a first susceptor material and a second susceptor material. The first susceptor material is in 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 primarily used to heat the susceptor when it is placed in a fluctuating electromagnetic field. Any suitable material may be used. For example, the first susceptor material may be aluminum, or it may be a ferrous material such as stainless steel. The second susceptor material is preferably used primarily to indicate when the susceptor reaches a specific 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. Thus, the Curie temperature of the second susceptor material must be below the ignition point of the aerosol-generating substrate. Suitable materials for the second susceptor material may include nickel and some nickel alloys.

By providing a susceptor having at least a first and a second susceptor material, with the second susceptor material having a Curie temperature and the first susceptor material not having a Curie temperature, or with first and second susceptor materials having different first and second Curie temperatures, the heating of the aerosol-generating substrate and the control of the heating temperature can be separated. The first susceptor material is preferably a magnetic material having a Curie temperature above 500 degrees Celsius. It is advantageous, from the standpoint of heating efficiency, that the Curie temperature of the first susceptor material be above any maximum temperature to which the susceptor must be able to be heated. The second Curie temperature can preferably be selected to be below 400 degrees Celsius, preferably below 380 degrees Celsius, or below 360 degrees Celsius. It is preferable that the second susceptor material be a magnetic material selected to have a second Curie temperature that is essentially the same as a desired maximum heating temperature. That is, it is preferable that the second Curie temperature be approximately the same as the temperature to which the susceptor must be heated to generate an aerosol from the aerosol-generating substrate. The second Curie temperature may, for example, be within the range of 200°C to 400°C, or between 250°C and 360°C. The second Curie temperature of the second susceptor material may, for example, be selected such that, when heated by a susceptor at a temperature equal to the second Curie temperature, the overall average temperature of the aerosol-generating substrate does not exceed 240°C.

As briefly described above, in aerosol-generating articles according to the present invention, the wrapper enclosing at least the aerosol-generating substrate rod comprises a wrapper base material having a basis weight. At least one treated portion of the wrapper, extending between the proximal and distal ends of the rod, comprises a flame-retardant composition comprising one or more flame-retardant compounds, such that the treated portion of the wrapper has a total basis weight greater than the basis weight of the wrapper base material. In practice, the wrapper enclosing at least the aerosol-generating substrate rod comprises a wrapper base material, and the flame-retardant composition is applied to the wrapper base material, or the wrapper base material is impregnated with the flame-retardant composition, or both. The treated portion comprises at least approximately 2 grams of the one or more flame-retardant compounds per square meter of surface area of the treated portion.

As used in the present description, the term “flame retardant composition” denotes a composition comprising one or more flame retardant compounds.

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

A flame retardant composition may typically also comprise one or more non-flame retardant compounds, i.e., one or more compounds, such as a solvent, an excipient, a filler, that do not actively contribute to providing the substrate with protection against flammability, but are used to facilitate the application of the flame retardant compound or compounds onto or within the wrapper or both.

Some of the non-flame retardant components of a flame retardant composition—such as solvents—are volatile and may evaporate from the wrapper after drying, once the flame retardant composition has been applied to or within the wrapper base material, or both. Therefore, even though such non-flame retardant components are part of the flame retardant composition formulation, they may no longer be present or may only be detectable in trace amounts in the wrapper of an aerosol-generating article according to the invention.

To incorporate a flame-retardant composition into a paper-based or polymer-based wrapper, the flame-retardant composition can be added to the pulp or polymer blend during the wrapper manufacturing process, or added to the wrapper at a later stage through an application process such as sizing, spraying, printing, coating, etc. The flame-retardant composition can be applied, for example, as a coating layer, on one side of the wrapper, or on both sides.

A number of suitable flame retardant compounds are known. Some flame retardants, such as mineral flame retardants, act primarily as additive flame retardants and do not chemically bond with the surrounding system. Most organohalogen and organophosphate compounds also do not permanently bond with their environment. Reactive flame retardants, such as certain non-halogenated products, are reactive because they integrate into the surrounding system without losing their retardant efficiency. This makes these materials advantageously non-emitting to the environment.

The wrapper base material surrounding at least the aerosol-generating substrate bar may be a paper wrapper base material or a non-paper wrapper base material. In preferred embodiments, the wrapper base material surrounding at least the aerosol-generating substrate bar comprises paper. Paper wrapper base materials suitable for use in the specific embodiments of the invention are known in the art and include, but are not limited to, cigarette papers and filter cap wrappers. Paper wrapper base materials suitable for use in the specific embodiments of the invention are known in the art and include, but are not limited to, sheets of homogenized tobacco materials and sheets of certain polymeric materials. In certain embodiments, the wrapper base material may be formed from a laminated material comprising a plurality of layers.

By way of example, the wrapping base material may have a basis weight of at least approximately 20 grams per square meter. Preferably, the wrapping base material has a basis weight of at least approximately 25 grams per square meter. More preferably, the wrapping base material has a basis weight of at least approximately 30 grams per square meter. Even more preferably, the wrapping base material has a basis weight of at least approximately 40 grams per square meter, or at least approximately 50 grams per square meter. In some embodiments, the wrapping base material has a basis weight of at least approximately 70 grams per square meter.

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

In preferred embodiments, the base wrapping material has a basis weight of less than or equal to approximately 150 grams per square meter, preferably less than or equal to approximately 140 grams per square meter, even more preferably less than or equal to approximately 130 grams per square meter, with the highest preference less than or equal to approximately 120 grams per square meter.

In some embodiments, the base wrapping material may have a basis weight of approximately 30 grams per square meter to approximately 220 grams per square meter, preferably approximately 40 grams per square meter to approximately 220 grams per square meter, with a higher preference of approximately 50 grams per square meter to approximately 220 grams per square meter, and with an even higher preference of approximately 60 grams per square meter to approximately 220 grams per square meter. In other embodiments, the base wrapping material may have a basis weight of approximately 30 grams per square meter to approximately 200 grams per square meter, preferably approximately 40 grams per square meter to approximately 200 grams per square meter, with a higher preference of approximately 50 grams per square meter to approximately 200 grams per square meter, and with an even higher preference of approximately 60 grams per square meter to approximately 200 grams per square meter. In additional embodiments, the base wrapping material may have a basis weight of approximately 30 grams per square meter to approximately 180 grams per square meter, preferably from approximately 40 grams per square meter to approximately 180 grams per square meter, with a higher preference from approximately 50 grams per square meter to approximately 180 grams per square meter, and with a further higher preference from approximately 60 grams per square meter to approximately 180 grams per square meter. In still other embodiments, the base wrapping material may have a basis weight of approximately 30 grams per square meter to approximately 160 grams per square meter, preferably from approximately 40 grams per square meter to approximately 160 grams per square meter, with a higher preference from approximately 50 grams per square meter to approximately 160 grams per square meter, and with a further higher preference from approximately 60 grams per square meter to approximately 160 grams per square meter.

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

In other forms, the base wrapping material may have a basis weight of approximately 20 grams per square meter to approximately 120 grams per square meter, preferably approximately 25 grams per square meter to approximately 120 grams per square meter, with a higher preference of approximately 30 grams to approximately 120 grams per square meter, with a further higher preference of approximately 40 grams per square meter to approximately 120 grams per square meter, with the highest preference of approximately 50 grams per square meter to approximately 120 grams per square meter. In further embodiments, the base wrapping material may have a basis weight of approximately 20 grams per square meter to approximately 100 grams per square meter, preferably from approximately 25 grams per square meter to approximately 100 grams per square meter, with a higher preference of approximately 30 grams per square meter to approximately 100 grams per square meter, with an even higher preference of approximately 40 grams per square meter to approximately 100 grams per square meter, with a maximum preference of approximately 50 grams per square meter to approximately 100 grams per square meter. In still further embodiments, the base wrapping material may have a basis weight of approximately 20 grams per square meter to approximately 80 grams per square meter, preferably from approximately 25 grams per square meter to approximately 80 grams per square meter, with a higher preference of approximately 30 grams per square meter to approximately 80 grams per square meter, with an even higher preference of approximately 40 grams per square meter to approximately 80 grams per square meter, with a maximum preference of approximately 50 grams per square meter to approximately 80 grams per square meter. In alternative embodiments, the base wrapping material may have a basis weight of approximately 20 grams per square meter to approximately 70 grams per square meter, preferably from approximately 25 grams per square meter to approximately 70 grams per square meter, with greater preference from approximately 30 grams to approximately 70 grams per square meter, with even greater preference from approximately 40 grams per square meter to approximately 70 grams per square meter, with the maximum preference from approximately 50 grams per square meter to approximately 70 grams per square meter.

In other forms, the base wrapping material may have a basis weight of approximately 20 grams per square meter to approximately 50 grams per square meter, preferably approximately 25 grams per square meter to approximately 50 grams per square meter, with greater preference of approximately 30 grams to approximately 50 grams per square meter, and even more preferentially approximately 40 grams per square meter to approximately 50 grams per square meter.

The wrapper enclosing at least the aerosol-generating substrate bar has an overall dry basis weight that is the sum of the basis weight of the wrapper base material and the weight of the flame-retardant composition components present on or within the wrapper base material, or both. The weight of the flame-retardant composition components present on or within the wrapper is the sum of the total weight of the flame-retardant compound(s) and the weight of any residual non-flame-retardant compound. Within the context of the present invention, the weight of the flame-retardant composition components is also expressed in grams of components per square meter of wrapper base material.

The ratio of the total weight of the flame retardant compound(s) to the overall dry basis weight of the wrapper can be considered as an indication of the concentration of the flame retardant compound(s) in the wrapper.

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

Preferably, the ratio of the total weight of the flame retardant compound(s) to the overall dry basis weight of the casing is less than or equal to approximately 0.20. More preferably, the ratio of the total weight of the flame retardant compound(s) to the overall dry basis weight of the casing is less than or equal to approximately 0.15. Even more preferably, the ratio of the total weight of the flame retardant compound(s) to the overall dry basis weight of the casing is less than or equal to approximately 0.10. In some embodiments, the ratio of the total weight of the flame retardant compound(s) to the overall dry basis weight of the casing may be from approximately 0.02 to approximately 0.20, preferably from approximately 0.03 to approximately 0.20, more preferably from approximately 0.04 to approximately 0.20, and even more preferably from approximately 0.05 to approximately 0.20. In other embodiments, the ratio of the total weight of the flame retardant compound(s) to the overall dry basis weight of the casing may be from approximately 0.02 to approximately 0.15, preferably from approximately 0.03 to approximately 0.15, more preferably from approximately 0.04 to approximately 0.15, and even more preferably from approximately 0.05 to approximately 0.15. In additional embodiments, the ratio of the total weight of the flame retardant compound(s) to the overall dry basis weight of the casing may be from approximately 0.02 to approximately 0.10, preferably from approximately 0.03 to approximately 0.10, more preferably from approximately 0.04 to approximately 0.10, and even more preferably from approximately 0.05 to approximately 0.10.

In an aerosol-generating article according to the present invention, the flame-retardant composition is provided in a treated portion of the wrapper. This means that the flame-retardant composition has been applied on or within a corresponding portion of a wrapper base material, or both. Therefore, in the treated portion, the wrapper has a total dry basis weight that is greater than the dry basis weight of the wrapper base material.

The treated portion of the wrapper may extend over at least approximately 10 percent of the external surface area of the aerosol-generating substrate bar enclosed by the wrapper. Preferably, the treated portion of the wrapper extends over at least approximately 20 percent of the external surface area of the aerosol-generating substrate bar enclosed by the wrapper. More preferably, the treated portion of the wrapper extends over at least approximately 40 percent of the external surface area of the aerosol-generating substrate bar. Even more preferably, the treated portion of the wrapper extends over at least approximately 60 percent of the external surface area of the aerosol-generating substrate bar. Most preferably, the treated portion of the wrapper extends over at least approximately 80 percent of the external surface area of the aerosol-generating substrate bar.

In particularly preferred embodiments, the treated portion of the wrap extends over at least approximately 90 percent of the external surface area of the aerosol-generating substrate bar. Even more preferably, the treated portion of the wrap extends over at least approximately 95 percent of the external surface area of the aerosol-generating substrate bar. With the highest preference, the treated portion of the wrap extends over essentially the entire external surface area of the aerosol-generating substrate bar.

The length of the treated area may be at least approximately 10 percent of the length of the aerosol-generating substrate bar. Preferably, the length of the treated area is at least approximately 20 percent of the length of the aerosol-generating substrate bar. More preferably, the length of the treated area is at least approximately 40 percent of the length of the aerosol-generating substrate bar. Still more preferably, the length of the treated area is at least approximately 60 percent of the length of the aerosol-generating substrate bar. Most preferably, the length of the treated area is at least approximately 80 percent of the length of the aerosol-generating substrate bar.

In particularly preferred modes, a length of the treated area is at least approximately 90 percent of a length of the aerosol-generating substrate bar. Even more preferably, a length of the treated area is at least approximately 95 percent of a length of the aerosol-generating substrate bar. With the highest preference, a length of the treated area is essentially equal to a length of the aerosol-generating substrate bar.

As described above, in aerosol-generating articles according to the present invention, the treated portion of the wrapper comprises at least approximately 2.0 grams of the flame-retardant compound(s) per square meter of surface area of the treated portion. Preferably, the treated portion of the wrapper comprises at least approximately 2.5 grams of the flame-retardant compound(s) per square meter of surface area of the treated portion. More preferably, the treated portion of the wrapper comprises at least approximately 3.0 grams of the flame-retardant compound(s) per square meter of surface area of the treated portion, or even more preferably, at least approximately 4.0 grams of the flame-retardant compound(s) per square meter of surface area of the treated portion. In particularly preferred embodiments, the treated portion of the wrapper comprises at least approximately 5.0 grams of the flame-retardant compound(s) per square meter of surface area of the treated portion.

Preferably, the treated portion of the wrapping comprises less than or equal to approximately 12 grams of the flame retardant compound(s) per square meter of surface area of the treated portion. More preferably, the treated portion of the wrapping comprises less than or equal to approximately 10 grams of the flame retardant compound(s) per square meter of surface area of the treated portion. Even more preferably, the treated portion of the wrapping comprises less than or equal to approximately 8 grams of the flame retardant compound(s) per square meter of surface area of the treated portion.

In some embodiments, the treated portion of the wrapper comprises from approximately 2.0 grams to approximately 12 grams of the flame retardant compound or compounds per square meter of surface area of the treated portion, even more preferably from approximately 3.0 grams to approximately 12 grams of the flame retardant compound or compounds per square meter of surface area of the treated portion.

In other embodiments, the treated portion of the wrapping comprises from approximately 2.0 grams to approximately 10 grams of the flame retardant compound or compounds per square meter of surface area of the treated portion, even more preferably from approximately 3.0 grams to approximately 120 grams of the flame retardant compound or compounds per square meter of surface area of the treated portion.

In additional embodiments, the treated portion of the wrapping comprises from approximately 2.0 grams to approximately 8 grams of the flame retardant compound or compounds per square meter of surface area of the treated portion, even more preferably from approximately 3.0 grams to approximately 8 grams of the flame retardant compound or compounds per square meter of surface area of the treated portion.

Depending on the concentration of the flame retardant compound(s) in the flame retardant composition, different amounts of flame retardant composition can be applied to achieve the required flame retardant loading on the treated portion of the wrapping described above. For example, at least approximately 10 grams of flame retardant composition can be applied to the treated portion per square meter of surface area.

Preferably, at least approximately 12 grams of the flame retardant composition are applied to the treated portion per square meter of surface area. More preferably, at least approximately 14 grams of the flame retardant composition are applied to the treated portion per square meter of surface area. Even more preferably, at least approximately 16 grams of the flame retardant composition are applied to the treated portion per square meter of surface area. In particularly preferred embodiments, at least approximately 18 grams or at least approximately 20 grams of the flame retardant composition are applied to the treated portion per square meter of surface area.

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

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

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

In additional embodiments, approximately 10 grams to approximately 25 grams of the flame retardant composition are applied to the treated portion per square meter of surface area. Preferably, approximately 12 grams to approximately 25 grams of the flame retardant composition are applied to the treated portion per square meter of surface area. More preferably, approximately 14 grams to approximately 25 grams of the flame retardant composition are applied to the treated portion per square meter of surface area. Even more preferably, approximately 16 grams to approximately 25 grams of the flame retardant composition are applied to the treated portion per square meter of surface area. In particularly preferred embodiments, approximately 18 grams to approximately 25 grams or approximately 20 grams to approximately 25 grams of the flame retardant composition are applied to the treated portion per square meter of surface area.

In aerosol-generating articles according to the present invention, the flame-retardant compound or compounds in the treated portion are preferably formulated such that, when the aerosol-generating article is heated to 500 degrees Celsius using a resistance-heated coil for at least 5 seconds, preferably for 30 seconds, the aerosol-generating article does not ignite. The term “does not ignite” is used herein to refer in particular to the fact that combustion of the envelope surrounding the aerosol-generating substrate does not begin, and no flame is detected.

Preferably, the aerosol-generating articles according to the present invention do not ignite when subjected to the intensive Canadian health regime, which comprises a pre-ignition stage using a resistance-heated coil, and a puffing regime of one 55-milliliter puff lasting 2 seconds every 30 seconds with 100 percent of the ventilation zone in the aerosol-generating article (if present) blocked. Further details regarding the “smoking” parameters and standard test conditions are provided in ISO 3308:2000 (Analytical cigarette smoking machine routine — Definitions and standard conditions).

In some embodiments, the wrapper comprises a wrapper base material and a layer comprising the flame-retardant compound(s) provided on a surface of the wrapper base material oriented toward the aerosol-generating substrate. In other embodiments, the wrapper comprises a wrapper base material and a layer comprising the flame-retardant compound(s) provided on a surface of the wrapper base material oriented away from the aerosol-generating substrate. In further embodiments, the wrapper comprises a wrapper base material, and the layers comprising the flame-retardant compound(s) are provided on both surfaces of the wrapper base material.

Those skilled in the art will be familiar with a number of suitable flame retardant compounds. In particular, several flame retardant compounds and formulations suitable for treating cellulosic materials are known and have been described and may find use in the manufacture of packaging for aerosol-generating articles according to the present 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, pyrophosphoric 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 tri-carboxylic acid and the hydroxide or salt form a carboxylate and the at least one polyphosphoric, pyrophosphoric and/or phosphoric acid and the hydroxide or salt form a phosphate.

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

In other embodiments, the flame retardant composition comprises cellulose modified with at least one C10 or higher fatty acid, total oil fatty acid (TOFA), phosphorylated linseed oil, or downstream phosphorylated corn oil. Preferably, the at least one C10 or higher fatty acid is selected from the group consisting of capric acid, myristic acid, palmitic acid, and combinations thereof.

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

According to the invention, the downstream section of the aerosol generating article may comprise, in particular, a nozzle element positioned downstream of the aerosol generating substrate bar and in longitudinal alignment with the aerosol generating substrate bar.

The nozzle element is preferably located at the downstream or mouth-side end of the aerosol-generating article and extends to the mouth-side end of the aerosol-generating article. Preferably, the nozzle element comprises at least one nozzle filter segment made of a fibrous filter material for filtering the aerosol generated from the aerosol-generating substrate. Suitable fibrous filter materials will be known to those skilled in the art. Particularly, and most preferably, the at least one nozzle filter segment comprises a cellulose acetate filter segment formed from cellulose acetate tow.

In certain preferred embodiments, the nozzle element consists of a single nozzle filter segment. In alternative embodiments, the nozzle element includes two or more axially aligned nozzle filter segments in an adjacent end-to-end relationship to each other.

In certain embodiments of the invention, the downstream section may comprise a mouth-side end cavity at the downstream end, located downstream of the nozzle element as described above. The mouth-side end cavity may be defined by a hollow tubular element provided at the downstream end of the nozzle. Alternatively, the mouth-side end cavity may be defined by the outer envelope of the nozzle element, wherein the outer envelope extends downstream of the nozzle element.

The nozzle element may optionally comprise a flavoring, which may be provided in any suitable form. For example, the nozzle element may comprise one or more capsules, pearls, or granules of a flavoring, or one or more flavor-loaded threads or filaments.

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

The support element can be formed from any suitable material or combination of materials. For example, the support element can be formed from one or more materials selected from the group consisting of: cellulose acetate; cardboard; crepe paper, such as heat-resistant crepe paper or parchment crepe 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 segment. In a preferred embodiment, the support element comprises a hollow cellulose acetate tube.

The support element is essentially aligned with the bar. This means that the length dimension of the support element is arranged to be approximately parallel to the longitudinal direction of the bar and the article, for example, within ±10 degrees of parallel to the longitudinal direction of the bar. In preferred embodiments, the support element extends along the longitudinal axis of the bar.

The support element preferably has an external diameter that is approximately equal to the external diameter of the aerosol-generating substrate bar and the external diameter of the aerosol-generating article.

A peripheral wall of the support element may have a thickness of at least 1 millimeter, preferably at least approximately 1.5 millimeters, more preferably at least approximately 2 millimeters.

The support element can have a length of between approximately 5 millimeters and approximately 15 millimeters.

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

In preferred embodiments, the support element has a length of less than approximately 12 millimeters, with greater preference less than approximately 10 millimeters.

In some embodiments, the support element is approximately 5 to 15 millimeters long, preferably approximately 6 to 15 millimeters, with a higher preference for approximately 7 to 15 millimeters. In other embodiments, the support element is approximately 5 to 12 millimeters long, preferably approximately 6 to 12 millimeters, with a higher preference for approximately 7 to 12 millimeters. In further embodiments, the support element is approximately 5 to 10 millimeters long, preferably approximately 6 to 10 millimeters, with a higher preference for approximately 7 to 10 millimeters.

In a preferred embodiment, the support element has a length of approximately 8 millimeters.

In some embodiments, the downstream section further comprises an aerosol cooling element located immediately downstream of the support element. The nozzle element is preferably located downstream of both the support element and the aerosol cooling element. Particularly preferable, the nozzle element is located immediately downstream of the aerosol cooling element. By way of example, the nozzle element may be adjacent to the downstream end of the aerosol cooling element.

The aerosol cooling element is essentially aligned with the bar. This means that the longitudinal dimension of the aerosol cooling element is arranged to be approximately parallel to the longitudinal direction of the bar and the article, for example, within ±10 degrees of parallel to the longitudinal direction of the bar. In preferred embodiments, the aerosol cooling element extends along the longitudinal axis of the bar.

The aerosol cooling element preferably has an outer diameter approximately equal to the outer diameter of the aerosol generating substrate bar and the outer diameter of the aerosol generating article.

In some embodiments, the aerosol cooling element has the form of a hollow tubular segment that defines a cavity extending from an upstream end of the aerosol cooling element to a downstream end of the aerosol cooling element, and a ventilation zone is provided at a location along the hollow tubular segment.

As used in this description, the term "hollow tubular segment" denotes a generally elongated element that defines an airflow lumen or passage along its longitudinal axis. Specifically, the term "tubular" will be used hereafter with reference to a tubular element having an essentially cylindrical cross-section and defining at least one airflow duct that establishes continuous communication between an upstream end and a downstream end of the tubular element. However, it is understood that alternative geometries (e.g., alternative cross-sectional shapes) of the tubular element are possible.

A hollow tubular segment provides an unrestricted flow channel. This means that the hollow tubular segment provides a negligible level of draft resistance (RTD). Therefore, the flow channel must be free of any components that obstruct airflow in a longitudinal direction. Preferably, the flow channel is essentially 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, e.g., twice or more its width dimension or its diameter dimension.

A peripheral wall of the aerosol cooling element may have a thickness of less than approximately 2.5 millimeters, preferably less than approximately 1.5 millimeters, more preferably less than approximately 1250 micrometers, and even more preferably less than approximately 1000 micrometers. In particularly preferred embodiments, the peripheral wall of the aerosol cooling element has a thickness of less than approximately 900 micrometers, preferably less than approximately 800 micrometers. The aerosol cooling element may have a length of between 5 millimeters and 15 millimeters.

Preferably, the aerosol cooling element has a length of at least 6 millimeters, with greater preference being approximately 7 millimeters.

In preferred embodiments, the aerosol cooling element has a length of less than approximately 12 millimeters, with greater preference less than approximately 10 millimeters.

In some embodiments, the aerosol cooling element is approximately 5 mm to approximately 15 mm long, preferably approximately 6 mm to approximately 15 mm, with a higher preference for approximately 7 mm to approximately 15 mm. In other embodiments, the aerosol cooling element is approximately 5 mm to approximately 12 mm long, preferably approximately 6 mm to approximately 12 mm, with a higher preference for approximately 7 mm to approximately 12 mm. In further embodiments, the aerosol cooling element is approximately 5 mm to approximately 10 mm long, preferably approximately 6 mm to approximately 10 mm, with a higher preference for approximately 7 mm to approximately 10 mm.

In particularly preferred embodiments of the invention, the aerosol cooling element is less than 10 millimeters long. For example, in one particularly preferred embodiment, the aerosol cooling element is 8 millimeters long. In such embodiments, the aerosol cooling element is therefore relatively short compared to the aerosol cooling elements of prior art aerosol-generating articles. This reduction in the length of the aerosol cooling element is possible due to the optimized effectiveness of the hollow tubular segment that forms the aerosol cooling element in cooling and nucleating the aerosol. Reducing the length of the aerosol cooling element advantageously reduces the risk of deformation of the aerosol-generating article due to compression during use, since the aerosol cooling element typically has lower resistance to deformation than the nozzle. Furthermore, reducing the length of the aerosol cooling element can provide an economic benefit to the manufacturer, as the cost of a hollow tubular segment is typically higher per unit length than the cost of other elements, such as a nozzle element.

A ratio between the length of the aerosol cooling element and the length of the aerosol generating substrate bar can be from approximately 0.25 to approximately 1.

The aerosol cooling element can be formed from any suitable material or combination of materials. For example, the aerosol cooling element can be formed from one or more materials selected from the group consisting of: cellulose acetate; cardboard; crepe paper, such as heat-resistant crepe paper or parchment crepe paper; 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 the peripheral wall of the aerosol cooling element. Preferably, the ventilation zone comprises at least one circumferential row of perforations. In some preferred embodiments, the ventilation zone may comprise two circumferential rows of perforations. For example, the perforations may be formed in a line during the manufacture of the aerosol-generating article. Preferably, each circumferential row of perforations comprises from 8 to 30 perforations.

An aerosol generating article according to the present invention may have a ventilation level of at least approximately 5 percent.

The term “ventilation level” is used throughout this description to denote a volume ratio between the airflow admitted into the aerosol-generating article through the vent zone (vent airflow) and the sum of the aerosol airflow and the vent airflow. The higher the ventilation level, the greater the dilution of the aerosol flow delivered to the consumer.

Preferably, an aerosol-generating article according to the present invention may have a ventilation level of at least approximately 10 percent, more preferably at least approximately 15 percent, and even more preferably at least approximately 20 percent. In particularly preferred embodiments, an aerosol-generating article according to the present invention has a ventilation level of at least approximately 25 percent. Not wishing to be limited to theory, the inventors have discovered that the temperature drop caused by the admission of cooler external air into the hollow tubular segment through the ventilation zone can have an advantageous effect on the nucleation and growth of aerosol particles. The rapid cooling induced by the admission of external air into the hollow tubular segment through the ventilation zone can be used favorably to promote the nucleation and growth of aerosol droplets. However, at the same time, the admission of external air into the hollow tubular segment has the immediate disadvantage of diluting the aerosol stream delivered to the consumer. The inventors have surprisingly discovered that the dilution effect on the aerosol – which can be assessed by measuring, in particular, the effect on the supply of aerosol former (such as glycerol) included in the aerosol-generating substrate – is advantageously minimized when the ventilation level is within the ranges described above.

In some embodiments, the aerosol-generating article may further comprise an additional cooling element that defines a plurality of longitudinally extending channels, such that a high surface area is available for heat exchange. In other words, one of these additional cooling elements is adapted to function essentially as a heat exchanger. The plurality of longitudinally extending channels may be defined by a sheet-like 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 that has been pleated, gathered, or folded to form multiple channels. The sheet may also have been curled before being pleated, gathered, or folded. Alternatively, the plurality of longitudinally extending channels may be defined by multiple sheets that have been curled, pleated, gathered, or folded to form multiple channels. In some embodiments, the plurality of longitudinally extending channels can be defined by multiple sheets that have been curled, pleated, gathered, or folded together—that is, by two or more sheets that have been brought into the overlapping arrangement and then curled, pleated, gathered, or folded as one. As used in the present description, the term 'sheet' denotes a sheet-like element having a width and length substantially greater than its thickness.

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

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

The additional cooling element preferably comprises a sheet-like material selected from the group consisting of a metal foil, a polymer sheet, and an essentially non-porous paper or cardboard. In some embodiments, the aerosol cooling element may comprise a sheet-like 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 PLA sheet.

The aerosol-generating article may further comprise a section located upstream of the aerosol-generating substrate bar. The upstream section may comprise one or more upstream elements. In some embodiments, the upstream section may comprise an upstream element disposed immediately upstream of the aerosol-generating substrate bar.

The aerosol-generating article of the present invention preferably comprises an upstream element located upstream 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, the upstream element can prevent direct physical contact with the upstream end of the susceptor element. This helps prevent displacement or deformation of the susceptor element during handling or transport of the aerosol-generating article. This, in turn, helps ensure the shape and position of the susceptor element. Furthermore, the presence of an upstream element helps prevent any loss of the substrate.

The upstream element can also enhance the appearance of the upstream end of the aerosol-generating item. Additionally, if desired, the upstream element can be used to provide information about the aerosol-generating item, such as brand, flavor, contents, or details of the aerosol-generating device with which the item is intended for use.

The upstream element may be a porous plug element. Preferably, a porous plug element does not alter the suction resistance of the aerosol-generating article. Preferably, the upstream element has a porosity of at least approximately 50 percent in the longitudinal direction of the aerosol-generating article. More preferably, the upstream element has a porosity of between approximately 50 percent and approximately 90 percent in the longitudinal direction. 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 position 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 is evenly distributed over the cross-section of the upstream element.

The porosity or permeability of the upstream element can be advantageously varied to provide a convenient overall suction resistance of the aerosol-generating article.

Preferably, the RTD of the upstream element is at least approximately 5 mm H2O. More preferably, the RTD of the upstream element is at least approximately 10 mm H2O. Even more preferably, the RTD of the upstream element is at least approximately 15 mm H2O. In particularly preferred embodiments, the RTD of the upstream element is at least approximately 20 mm H2O.

The RTD of the upstream element is preferably less than or equal to approximately 80 millimeters of H2O. More preferably, the RTD of the upstream element is less than or equal to approximately 60 millimeters of H2O. Even more preferably, the RTD of the upstream element is less than or equal to approximately 40 millimeters of H2O.

In alternative embodiments, the upstream element may be formed from a material that is impermeable to air. In such embodiments, the aerosol-generating article may be configured so that air flows to the aerosol-generating substrate bar through suitable ventilation means provided in an enclosure.

The upstream element may be made of any material suitable for use in an aerosol-generating article. For example, the upstream element may be made of the same material used for one of the other components of the aerosol-generating article, such as the nozzle, cooling element, or support element. Suitable materials for forming the upstream element include filter materials, ceramics, polymer materials, cellulose acetate, cardboard, zeolite, or aerosol-generating substrate. Preferably, the upstream element is formed from a cellulose acetate plug.

Preferably, the upstream element is made of a heat-resistant material. For example, preferably the upstream element is made of a material that withstands 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 upstream element has a diameter that is approximately equal to the diameter of the aerosol generating article.

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

The upstream element is preferably enclosed by a casing. The casing enclosing the upstream element is preferably a rigid plug casing, for example, a plug casing having a basis weight of at least approximately 80 grams per square meter (g/m²), or at least approximately 100 g/m², or at least approximately 110 g/m². This provides structural rigidity to the upstream element.

Preferably, in an aerosol generating article according to the present invention, the casing does not contain metal. As used herein, with reference to the present invention, the term “metal” denotes the content of metals in an oxidation state of 0, i.e., the content of metals in the casing as elements in their free form. Therefore, the content of metals, such as alkali metals or alkaline earth metals, which may be present in ionic form or bonded to another element in one or more flame retardant compounds of the flame retardant composition, is not encompassed by the term “metal” as used herein.

In other words, the wrapper of an aerosol generating article according to the present invention preferably does not contain any metal in an oxidation state of 0.

Therefore, the aerosol-generating articles according to the present invention advantageously do not include a metal sheet acting as a thermal protection element. In particular, the aerosol-generating substrate is not enclosed by such a metal sheet thermal protection element.

The aerosol-generating articles according to the invention as described above can be manufactured by a method comprising a first step of providing a continuous bar of aerosol-generating substrate. One such method comprises a second step of enclosing the continuous bar of aerosol-generating substrate with a wrapper, wherein the wrapper comprises a wrapper base material having a dry basis weight. The method further comprises a third step of treating at least a portion of the wrapper with a flame-retardant composition comprising one or more flame-retardant compounds, such as to provide a treated portion of the wrapper having a total dry basis weight greater than the dry basis weight of the wrapper base material. The method further comprises a fourth step of cutting the treated continuous bar of aerosol-generating substrate into discrete bars, each discrete bar extending from a proximal end of the discrete bar to a distal end of the discrete bar upstream of the proximal end of the discrete bar. In each discrete bar, a treated portion of the wrapper comprises at least approximately 2 grams of the one or more flame-retardant compounds per square meter of surface area of the treated portion.

The flame retardant composition can be applied to at least one side of a wrapper base material by an application process based on sizing, spraying, printing, or coating.

An aerosol generating article according to the present invention finds use in particular in an aerosol generating system comprising the aerosol generating article and an electrically operated aerosol generating device, wherein the aerosol generating device comprises a heater and an elongated heating chamber configured to receive the aerosol generating article such that the aerosol generating substrate of the article is heated in the heating chamber.

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

In other embodiments, the heater may comprise an elongated, essentially cylindrical heating element, and the heating chamber is arranged around a longitudinal, circumferential surface of the heater. Consequently, during use, the thermal energy supplied by the heater travels radially outward from a surface of the heater into the heating chamber and the aerosol-generating article. However, other shapes and configurations of the heater and heating chamber may be used alternatively. The heater may comprise a plurality of individual heating elements, the various heating elements being operated independently of each other so that different elements may be activated at different times to heat the aerosol-generating article. By way of example, the heater may comprise a plurality of axially aligned heating elements, providing a plurality of independent heating zones along the length of the heater. Each heating element may be significantly shorter than the overall length of the heater. Therefore, when an individual heating element is activated, it supplies thermal energy to a portion of the aerosol-generating substrate located radially around the heating element without essentially heating the remainder of the aerosol-generating substrate. Therefore, different sections of the aerosol generating substrate can be heated independently and at different times.

Alternatively, or additionally, the heater may comprise a plurality of elongated heating elements extending longitudinally at different locations around the heater's longitudinal axis. Therefore, when an individual heating element is activated, it supplies thermal energy to a longitudinal portion of the aerosol-generating substrate that is essentially parallel and adjacent to the heating element. This arrangement also allows for the independent heating of different portions of the aerosol-generating substrate.

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

In additional embodiments, the aerosol generating article comprises a susceptor disposed within the aerosol generating substrate. The susceptor is 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. The electromagnetic energy released by the induction coils is absorbed by the susceptor and converted into heat, which is then transferred to the aerosol generating substrate, primarily by conduction.

The invention will now be further described with reference to the accompanying Figure drawings, where:

Figure 1 shows a schematic side-section view of the aerosol generating article according to one embodiment of the invention; and

Figure 2 shows a schematic side section view of the aerosol generating article according to one embodiment of the invention.

The aerosol-generating article 10 shown in Figure 1 comprises a bar 12 of the aerosol-generating substrate and a downstream section 14 located downstream of the bar 12 of the aerosol-generating substrate. In addition, the aerosol-generating article 10 comprises an upstream section 16 located upstream of the bar 12 of the aerosol-generating substrate. Therefore, the aerosol-generating article 10 extends from an upstream or distal end 18 to a downstream or mouth-side end 20.

The aerosol generating item has a total length of approximately 45 millimeters.

The downstream section 14 comprises a support element 22 located immediately downstream of the aerosol-generating substrate bar 12, the support element 22 being longitudinally aligned with the bar 12. In the embodiment of Figure 1, the upstream end of the support element 18 abuts the downstream end of the aerosol-generating substrate bar 12. Furthermore, 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 bar 12 and the support element 22. In the embodiment of Figure 1, the upstream end of the aerosol cooling element 24 abuts the downstream end of the support element 22. In the embodiment of Figure 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 segment 26. The first hollow tubular segment 26 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The first hollow tubular segment 26 defines an internal cavity 28 that extends from an upstream end 30 of the first hollow tubular segment to a downstream end 32 of the first hollow tubular segment 20. The internal cavity 28 is essentially empty, and therefore an essentially unrestricted airflow is permitted along the internal cavity 28.

The first hollow tubular segment 26 has a length of approximately 8 millimeters, an outer diameter of approximately 7.25 millimeters, and an inner diameter of approximately 1.9 millimeters. Therefore, the thickness of a peripheral wall of the first hollow tubular segment 26 is approximately 2.67 millimeters.

The aerosol cooling element 24 comprises a second hollow tubular segment 34. The second hollow tubular segment 34 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The second hollow tubular segment 34 defines an internal cavity 36 that extends from an upstream end 38 of the second hollow tubular segment to a downstream end 40 of the second hollow tubular segment 34. The internal cavity 36 is essentially empty, and therefore an essentially unrestricted airflow is permitted along the internal cavity 36.

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

The aerosol-generating article 10 comprises a ventilation zone 60 provided at a location along the second hollow tubular segment 34. More specifically, the ventilation zone is provided approximately 2 millimeters from the upstream end of the second hollow tubular segment 34. The ventilation level of the aerosol-generating article 10 is approximately 25 percent.

In the embodiment of Figure 1, the downstream section 14 further comprises a nozzle element 42 located downstream of the intermediate hollow section 50. In more detail, the nozzle element 42 is positioned immediately downstream of the aerosol cooling element 24. As shown in the drawing of Figure 1, an upstream end of the nozzle element 42 abuts the downstream end 40 of the aerosol cooling element 18.

Nozzle element 42 is provided in the form of a cylindrical plug made of low-density cellulose acetate. Nozzle element 42 has a length of approximately 12 millimeters and an outer diameter of approximately 7.25 millimeters.

Bar 12 comprises an aerosol-generating substrate of one of the types described above. The density of the aerosol-generating substrate is approximately 600 milligrams per cubic centimeter.

The aerosol generating substrate bar 12 has an outer diameter of approximately 7.25 millimeters and a length of approximately 12 millimeters.

The aerosol-generating article 10 further comprises an elongated susceptor 44 within the bar 12 of the aerosol-generating substrate. In more detail, the susceptor 44 is arranged essentially longitudinally within the aerosol-generating substrate, such that it is approximately parallel to the longitudinal direction of the bar 12. As shown in the drawing in Figure 1, the susceptor 44 is positioned radially centrally within the bar and effectively extends along the longitudinal axis of the bar 12. In more detail, the susceptor 44 is in thermal contact with the aerosol-generating substrate. The susceptor 44 extends from an upstream end to a downstream end of the bar 12. In effect, the susceptor 44 has essentially the same length as the bar 12 of the aerosol-generating substrate.

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

The upstream section 16 comprises an upstream element 46 located immediately upstream of the bar 12 of the aerosol-generating substrate, the upstream element 46 being in longitudinal alignment with the bar 12. In the embodiment of Figure 1, the downstream end of the upstream element 46 abuts the upstream end of the bar 12 of the aerosol-generating substrate. This advantageously prevents the susceptor 44 from separating. Furthermore, this ensures that the consumer cannot accidentally come into contact with the heated susceptor 44 after use.

The upstream element 46 is provided as a cylindrical cellulose acetate plug enclosed in a rigid shell. The upstream element 46 is approximately 5 millimeters long. The RTD of the upstream element 46 is approximately 30 millimeters of H₂O.

As shown in Figure 1, the aerosol-generating article 10 further comprises a wrapper 70 enclosing the bar 12 of the aerosol-generating substrate. The wrapper 70 comprises a wrapper base material having a basis weight of approximately 90 grams per square meter. In addition, the wrapper 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 treated portion 72 of the wrapper that extends between the proximal and distal ends of the aerosol-generating substrate bar 12. The treated portion 72 comprises approximately 3.5 grams of one or more flame retardant compounds per square meter of surface area of the treated portion 72. Therefore, the treated portion 72 of the wrapper 70 has a total basis weight that is greater than the basis weight of the wrapper base material. In the embodiment of Figure 1, the treated portion 72 has a length that essentially coincides with the length of the aerosol-generating substrate bar 12 and extends essentially over the entire external surface area of the aerosol-generating substrate bar 12.

The aerosol generating item 110 shown in Figure 2 has a number of elements in common with the aerosol generating item 10 in Figure 1 and will be described below only in what differs from aerosol generating item 10.

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

Similar to downstream section 14 of aerosol generating article 10, the modified downstream section 114 of aerosol generating article 110 comprises a support element 22 located immediately downstream of the bar 12 of the aerosol generating substrate, the support element 22 being in longitudinal alignment with the bar 12, wherein the upstream end of the support element 22 abuts the downstream end of the bar 12 of the aerosol generating substrate.

Furthermore, 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 in longitudinal alignment with the bar 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.

Unlike 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 essentially zero resistance to airflow through the bar. More specifically, the aerosol cooling element 124 is formed from a preferably non-porous sheet-like material selected from the group comprising a metal foil, a polymer sheet, and an essentially non-porous paper or cardboard. In particular, in the embodiment illustrated in Figure 2, the aerosol cooling element 124 is provided in the form of a crinkled and crimped sheet of polylactic acid (PLA). The aerosol cooling element 124 has a length of approximately 8 millimeters and an outer diameter of approximately 7.25 millimeters.

Similar to the embodiment in Figure 1, the aerosol-generating article 110 in Figure 2 further comprises a wrapper 70 enclosing the bar 12 of the aerosol-generating substrate. The wrapper 70 comprises a wrapper base material having a basis weight of approximately 90 grams per square meter. In addition, the wrapper 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 treated portion 72 of the wrapper that extends between the proximal and distal ends of the aerosol-generating substrate bar 12. The treated portion 72 comprises approximately 3.5 grams of one or more flame retardant compounds per square meter of surface area of the treated portion 72. Therefore, the treated portion 72 of the wrapper 70 has a total basis weight that is greater than the basis weight of the wrapper base material. In the embodiment of Figure 1, the treated portion 72 has a length that essentially coincides with the length of the aerosol-generating substrate bar 12 and extends essentially over the entire external surface area of the aerosol-generating substrate bar 12.

Claims (17)

1. An aerosol generating article (10, 110) for producing an inhalable aerosol upon heating, the aerosol generating article (10, 110) comprising: an aerosol-generating substrate bar (12) extending from a proximal end of the bar to a distal end of the bar upstream of the proximal end of the bar, wherein the aerosol-generating substrate comprises at least one aerosol former, an aerosol former content of the aerosol-generating substrate being at least 10 percent on a dry weight basis, and wherein the aerosol-generating substrate bar (12) further comprises a susceptor element (44) disposed within the aerosol-generating substrate; a downstream section (14, 114) at a location downstream of the aerosol-generating substrate bar (12); and an envelope (70) circumscribing at least the aerosol-generating substrate bar (12), the envelope (70) comprising an envelope base material having a dry basis weight; wherein at least a treated portion (72) of the sheath (70) extending between the proximal end of the bar and the distal end of the bar comprises a flame retardant composition comprising one or more flame retardant compounds, such that the treated portion (72) of the sheath (70) has an overall dry basis weight greater than the dry basis weight of the sheath base material; wherein the treated portion (72) comprises at least approximately 2 grams of one or more flame retardant compounds per square meter of surface area of the treated portion (72). 2. An aerosol generating article (10, 110) according to claim 1, wherein the treated portion (72) comprises at least approximately 3 grams of one or more flame retardant compounds per square meter of surface area of the treated portion (72). 3. An aerosol generating article (10, 110) according to claim 1 or 2, wherein the treated portion (72) comprises less than or equal to approximately 12 grams of one or more flame retardant compounds per square meter of surface area of the treated portion (72). 4. An aerosol generating article (10, 110) according to any of the preceding claims, wherein the dry basis weight of the wrapping base material is at least approximately 20 grams per square meter. 5. An aerosol generating article (10, 110) according to any preceding claim, wherein the dry basis weight of the wrapping base material is less than or equal to approximately 40 grams per square meter. 6. An aerosol generating article (10, 110) according to any preceding claim, wherein the treated portion (72) extends over at least approximately 90 percent of an external surface area of the aerosol generating substrate bar (12). 7. An aerosol generating article (10, 110) according to any preceding claim, wherein a length of the treated portion (72) is at least approximately 90 percent of a length of the aerosol generating substrate rod (12). 8. An aerosol generating article (10, 110) according to any preceding claim, wherein the wrapper (70) comprises a layer comprising the flame retardant composition provided on a surface of the wrapper base material oriented towards the aerosol generating substrate, or a surface of the wrapper base material oriented away from the aerosol generating substrate, or both. 9. An aerosol generating article (10, 110) according to any preceding claim, wherein 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, pyrophosphoric 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 tri-carboxylic acid and the hydroxide or salt form a carboxylate and the at least one polyphosphoric, pyrophosphoric and/or phosphoric acid and the hydroxide or salt form a phosphate. 10. An aerosol generating article (10, 110) according to claim 9, wherein the flame retardant composition further comprises an alkali or alkaline earth metal carbonate. 11. An aerosol generating article (10, 110) according to any of claims 1 to 8, wherein the flame retardant composition comprises cellulose modified with at least one C10 or higher fatty acid, high oil fatty acid (TOFA), phosphorylated linseed oil, downstream phosphorylated corn oil. 12. An aerosol generating article (10, 110) according to any of the preceding claims, wherein the casing (70) does not comprise metal. 13. An aerosol generating article (10, 110) according to any preceding claim, wherein the aerosol generating substrate rod (12) has a length of less than approximately 40 millimeters. 14. An aerosol generating article (10, 110) according to any preceding claim, wherein the aerosol generating substrate rod (12) comprises a crinkled sheet of homogenized tobacco material or a gel composition, the gel composition comprising at least one gelling agent, at least one alkaloid compound and one cannabinoid compound, and an aerosol former. 15. A method for manufacturing an aerosol-generating article (10, 110) for generating an inhalable aerosol upon heating, the method comprising: providing a continuous bar of aerosol-generating substrate, an aerosol former content of the aerosol-generating substrate that is at least 10 percent on a dry weight basis; circumscribing the continuous bar of aerosol-generating substrate with a wrap (70), the wrap (70) comprising a wrap base material having a dry basis weight; treating at least a portion of the wrapping (70) with a flame-retardant composition comprising one or more flame-retardant compounds, such as to provide a treated portion (72) of the wrapping (70) having a total dry basis weight greater than the dry basis weight of the wrapping base material, cutting the continuous wrapped treated bar of the aerosol-generating substrate into discrete bars (12), each discrete bar (12) extending from a proximal end of the discrete bar to a distal end of the discrete bar upstream of the proximal end of the discrete bar, such that in each discrete bar (12) a treated portion (72) of the wrapping (70) comprises at least approximately 2 grams of the one or more flame-retardant compounds per square meter of surface area of the treated portion (72); The method further comprises providing each discrete aerosol-generating substrate bar (12) with a susceptor element (44) disposed within the aerosol-generating substrate of the discrete bar (12). 16. A method according to claim 15, wherein a layer of the flame retardant composition is applied to at least one side of the wrapping base material by an application process based on sizing, spraying, printing or coating. 17. An aerosol generating system comprising an electrically operated aerosol generating device and an aerosol generating article (10, 110) according to any of claims 1 to 14, the aerosol generating device comprising means for heating the aerosol generating substrate rod (12) to a temperature sufficient to generate an aerosol from the aerosol generating substrate.