Aerosol-generating substrate with aerosol-generating film

Abstract

1. An aerosol-generating article (10)(70) comprising a rod of aerosol-generating substrate (14), wherein the rod of aerosol-generating substrate (14) comprises an aerosol-generating film (24)(76) comprising at least 25 weight percent of a polyhydric alcohol and at least 10 weight percent of a cellulosic film-forming agent, the aerosol-generating film (24)(76) being configured such that the exposed surface area of ​​the aerosol-generating film within the aerosol-generating substrate (14) is at least 5 square meters per milligram of the aerosol-generating film (24)(76), and the aerosol-generating film (24)(76) is substantially tobacco-free.

Description

[Technical field]

[0001] The present invention relates to aerosol-generating substrates formed with aerosol-generating films, and to aerosol-generating articles incorporating such aerosol-generating substrates. [Background technology]

[0002] Aerosol-generating articles in which an aerosol-generating substrate, such as a nicotine- or tobacco-containing substrate, is heated rather than burned therein, are known in the art. Typically, in such heated smoking articles, an aerosol is generated by transferring heat from a heat source to a physically separated aerosol-generating substrate or 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 entrained in the air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol.

[0003] Numerous prior art documents disclose aerosol generating devices for consuming aerosol-generating articles, including, for example, electrically heated aerosol generating devices, in which the aerosol is generated by heat transfer from one or more electric heater elements of the aerosol generating device to an aerosol-generating substrate of a heated aerosol-generating article.

[0004] Substrates for heated aerosol generating articles have often been produced in the past using randomly oriented pieces, strands, or strips of tobacco material. Alternatively, rods for heated aerosol generating articles formed from an assembly of sheets of tobacco material are disclosed, by way of example, in International Patent Application No. WO-A-2012 / 164009.

[0005] International Patent Application WO-A-2011 / 101164 discloses an alternative rod for a heated aerosol generating article formed from strands of homogenized tobacco material, which may be formed by casting, rolling, calendering or extrusion of a mixture comprising particulate tobacco and at least one aerosol former to form a sheet of homogenized tobacco material. In an alternative embodiment, the rod of International Patent Application WO-A-2011 / 101164 may be formed from strands of homogenized tobacco material obtained by extruding a mixture comprising particulate tobacco and at least one aerosol former to form a continuous length of homogenized tobacco material.

[0006] Alternative forms of nicotine-containing substrates have also been disclosed. By way of example, liquid nicotine compositions, often referred to as e-liquids, have been proposed. These liquid compositions can be heated, for example, by a coiled electrically resistive filament in an aerosol generating device.

[0007] This type of substrate may require special care in the manufacture of the container holding the liquid composition to prevent undesired leakage. To address this issue and simplify the overall manufacturing process, it has also been proposed to provide a gel composition containing nicotine that generates a nicotine-containing aerosol when heated. By way of example, International Patent Application No. WO-A-2018 / 019543 discloses a thermoreversible gel composition, i.e. a gel that becomes fluid when heated to a melting temperature and solidifies again into a gel at a gelling temperature. The gel is provided in a cartridge housing, which can be discarded and replaced when the gel is consumed.

[0008] It is desirable to provide an aerosol-generating article having a novel aerosol-generating film with improved stability. In addition, it is desirable to provide such an aerosol-generating article with an aerosol-generating film having a high aerosol former content so that it can be successfully used as an aerosol-generating substrate. In particular, it is desirable to provide such an aerosol-generating article that is easier to dispose of after use or has a reduced impact on the environment. It is further desirable to provide such an aerosol-generating article that optimizes the generation of aerosols from the aerosol-generating substrate during use. Summary of the Invention

[0009] The present invention relates to an aerosol-generating article comprising a rod of an aerosol-generating substrate comprising an aerosol-generating film. The aerosol-generating film may comprise at least about 25 weight percent of a polyhydric alcohol. The aerosol-generating film may comprise at least about 10 weight percent of a cellulosic film former. The aerosol-generating film may be configured such that the exposed surface area of ​​the aerosol-generating film within the aerosol-generating substrate is at least 5 square millimeters per milligram of aerosol-generating film. Alternatively or additionally, the aerosol-generating film may be configured such that the bulk density of the aerosol-generating film is at least about 100 mg per cubic centimeter of the aerosol-generating substrate.

[0010] According to a first aspect of the present invention there is provided an aerosol-generating article comprising a rod of aerosol-generating substrate, the rod of aerosol-generating substrate comprising an aerosol-generating film comprising at least 25% by weight of a polyhydric alcohol and at least 10% by weight of a cellulosic film former. The aerosol-generating film is configured such that the exposed surface area of ​​the aerosol-generating film within the rod of aerosol-generating substrate is at least about 5 square millimeters per milligram of aerosol-generating film. Preferably the aerosol-generating film is substantially free of tobacco.

[0011] According to a second aspect of the invention, there is provided an aerosol-generating article comprising a rod of aerosol-generating substrate, the rod of aerosol-generating substrate comprising an aerosol-generating film comprising at least about 25% by weight of a polyhydric alcohol and at least about 10% by weight of a cellulosic film former. The aerosol-generating film is configured such that the bulk density of the aerosol-generating film is at least about 100 mg / cubic centimeter of the rod of aerosol-generating substrate. Preferably, the aerosol-generating film is substantially free of tobacco.

[0012] According to a third aspect of the present invention there is provided a rod for use as an aerosol-generating substrate in an aerosol-generating article, the rod comprising an aerosol-generating film comprising at least about 25 weight percent polyhydric alcohol and at least about 10 weight percent cellulose film-forming agent, the aerosol-generating film configured such that the exposed surface area of ​​the aerosol-generating film within the rod of aerosol-generating substrate is at least about 5 square millimeters per milligram of aerosol-generating film. Preferably the aerosol-generating film is substantially free of tobacco.

[0013] According to a fourth aspect of the present invention there is provided a rod for use as an aerosol-generating substrate in an aerosol-generating article, the rod comprising an aerosol-generating film comprising at least about 25 weight percent polyhydric alcohol and at least about 10 weight percent cellulosic film-forming agent, the aerosol-generating film configured such that the bulk density of the aerosol-generating substrate is at least 100 mg per square millimeter of the rod of aerosol-generating substrate. Preferably the aerosol-generating film is substantially free of tobacco.

[0014] According to a fifth aspect of the present invention, there is provided an aerosol generation system comprising an electrically operated aerosol generating device comprising an aerosol-generating article as defined above in relation to the third and fourth aspects of the present invention, and a heater element configured to heat an aerosol-generating substrate of the aerosol-generating article, the aerosol-generating article comprising a rod of aerosol-generating substrate according to the present invention. The heater element of the aerosol-generating device is a heater blade or heater pin configured to be inserted into the rod of aerosol-generating substrate to heat the aerosol-generating film.

[0015] References herein to features of an aerosol-generating article or aerosol-generating substrate according to the invention are assumed to apply to all aspects of the invention, unless otherwise stated.

[0016] The term "aerosol-generating article" as used herein refers to an aerosol-generating article for the production of an aerosol that includes an aerosol-generating substrate that is intended to be heated, rather than combusted, to release volatile compounds capable of forming an aerosol.

[0017] The term "aerosol-generating substrate" as used herein refers to a substrate capable of releasing, upon heating, volatile compounds capable of forming an aerosol. The aerosol generated from the aerosol-generating substrate of the aerosol-generating articles described herein may be visible or invisible and may include vapor (e.g., fine particles of a substance in a gaseous state, e.g., of a substance that is normally a liquid or solid at room temperature) as well as gas and condensed vapor droplets.

[0018] Substrates for heated aerosol-generating articles typically include an "aerosol former," i.e., a compound or mixture of compounds that facilitates the formation of an aerosol during use and that is preferably substantially resistant to thermal decomposition at the use temperature of the aerosol-generating article. Examples of suitable aerosol formers include polyhydric alcohols (such as propylene glycol, triethylene glycol, 1,3-butanediol, glycerin, etc.), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate, dimethyl tetradecanedioate, etc.).

[0019] The polyhydric alcohols in the aerosol-generating films of the aerosol-generating articles of the present invention are also aerosol formers within the meaning described above.

[0020] The term "rod" as used herein refers to a generally cylindrical element of substantially polygonal cross-section, and preferably of circular, oval or elliptical cross-section.

[0021] As used herein, the term "film" refers to a solid, layered element that has a thickness that is less than its width or length.

[0022] The film may be self-supporting, that is to say, it may have cohesive and mechanical properties such that it can be separated from a supporting surface, even when obtained by casting a film-forming formulation onto the supporting surface.

[0023] Alternatively, the film may be placed on a support or sandwiched between other materials, which may enhance the mechanical stability of the film.

[0024] The "thickness" of an aerosol-generating film of an aerosol-generating article according to the present invention corresponds to the smallest distance measured between opposing substantially parallel surfaces of the film.

[0025] The thickness of the aerosol-generating film may correspond substantially to the thickness to which the corresponding film-forming composition was cast or extruded, because the cast or extruded film-forming composition does not substantially shrink during drying, despite loss of water.

[0026] The "weight" of the aerosol-generating film of the aerosol-generating article according to the present invention generally corresponds to the weight of the composition of the corresponding film-forming composition minus the weight of the water evaporated during the drying process. If the film is self-supporting, it can be weighed by itself. If the film is placed on a support, the film and support are weighed, and the weight of the support measured before deposition of the film is subtracted from the combined weight of the film and support.

[0027] Unless otherwise stated, the weight percentages of the components of the aerosol-generating film listed herein are based on the total weight of the aerosol-generating film.

[0028] As used herein, the term "longitudinal" refers to a direction corresponding to the main longitudinal axis of the aerosol-generating article extending between the upstream and downstream ends of the aerosol-generating article. During use, air is drawn through the aerosol-generating article in the longitudinal direction. The term "transverse" refers to a direction perpendicular to the longitudinal axis.

[0029] Any reference to a "cross-section" of an aerosol-generating article or a component of an aerosol-generating article refers to a transverse cross-section, unless otherwise specified. As used herein, the term "length" refers to the dimension of the component in the longitudinal direction, and the term "width" refers to the dimension of the component in the transverse direction.

[0030] As used herein, the terms "upstream" and "downstream" describe the relative location of an element (or part of an element) of an aerosol-generating article with respect to the direction in which aerosol is transported through the aerosol-generating article during use.

[0031] As noted above, the present invention provides an aerosol-generating article having a novel aerosol-generating substrate formed with an aerosol-generating film. Upon heating, an aerosol may be generated from the aerosol-generating film, emitted within the aerosol-generating article, and drawn through the aerosol-generating article into the mouth of a consumer. The aerosol-generating film may be provided in place of, or in addition to, any other aerosol-generating substrate within the aerosol-generating article.

[0032] In many embodiments of the invention, the aerosol-generating film may be configured to form a self-supporting rod, eliminating the need for additional support structures within the aerosol-generating substrate. In many cases, the rod of the aerosol-generating substrate may be formed from the aerosol-generating film using existing equipment and methods.

[0033] A rod of aerosol-generating substrate incorporating an aerosol-generating film may be easily incorporated into existing structures of aerosol-generating articles without the need for significant modification, and aerosol-generating articles according to the invention may therefore be capable of being manufactured at high speed using existing manufacturing equipment and methods.

[0034] The composition of the aerosol-generating film may be selected such that the majority of the components of the film evaporate upon heating during use of the aerosol-generating article, leaving behind minimal residue, which may advantageously provide an aerosol-generating article that is easy to dispose of and has a reduced impact on the environment.

[0035] The properties and composition of the aerosol-generating film can be easily tailored to control the resulting aerosol generated upon heating of the film. The use of an aerosol-generating film also allows for the provision of a highly consistent aerosol to the consumer.

[0036] The aerosol-generating article according to the invention is particularly suitable for use in aerosol-generating systems comprising an electrically heated aerosol generating device having an internal heater element for heating an aerosol-generating substrate, as described in more detail below. For example, the aerosol-generating article according to the invention finds particular application in aerosol-generating systems comprising an electrically heated aerosol generating device having an internal heater blade adapted to be inserted into the aerosol-generating article adjacent to a rod of the aerosol-generating substrate. Aerosol-generating articles of this type are described in the prior art, for example in European Patent No. EP-A-0822670.

[0037] The aerosol-generating films described herein are particularly suitable for being heated internally within an aerosol-generating article: when heated by an internal heater element, the aerosol-generating film on the inner surface of the tubular carrier element may contract, which may advantageously bring the aerosol-generating film closer to the surface of the heater element, thereby optimizing heating of the aerosol-generating film.

[0038] As used herein, the term "aerosol-generating device" refers to a device that includes a heater element that interacts with an aerosol-generating substrate of an aerosol-generating article to generate an aerosol.

[0039] Alternatively, the aerosol-generating article according to the invention may be provided with a combustible carbon heat source for heating the aerosol-generating substrate during use. Aerosol-generating articles of this type are described in the prior art, for example in International Patent Application No. WO-A-2009 / 022232.

[0040] According to the invention, the aerosol-generating film is configured to maximize the total exposed surface area of ​​the aerosol-generating film within the rod of aerosol-generating substrate. Maximizing the exposed surface area can improve the efficiency of aerosol emission from a given volume of aerosol-generating substrate. The "exposed" surface area of ​​the aerosol-generating film corresponds to the cumulative area of ​​uncovered and unobstructed surfaces within the rod of aerosol-generating substrate from which volatile components can be freely emitted upon heating of the aerosol-generating film. During use, the exposed surface of the aerosol-generating film can be exposed to a gas stream passing through the aerosol-generating article.

[0041] According to the present invention, the total exposed surface area of ​​the aerosol-generating film within the rod of the aerosol-generating substrate can be maximized by increasing the exposed surface area per unit weight of the aerosol-generating film. The efficiency of delivery of the aerosol from a given weight of the aerosol-generating film can thereby be improved. Thus, it may be possible to reduce the total weight of the aerosol-generating film required to generate a desired amount of aerosol from the rod of the aerosol-generating substrate during a heating cycle in an aerosol-generating device.

[0042] The exposed surface area of ​​the aerosol-generating film is preferably at least about 5 square millimeters per mg of aerosol-generating film, more preferably at least about 10 square millimeters per mg of aerosol-generating film, and most preferably at least about 20 square millimeters per mg of aerosol-generating film.

[0043] The exposed surface area of ​​the aerosol-generating film is preferably about 40 mm2 or less per mg of aerosol-generating film, more preferably about 30 mm2 or less per mg of aerosol-generating film. For example, the exposed surface area of ​​the aerosol-generating film may be about 5 mm2 to about 40 mm2 per mg of aerosol-generating film, or about 10 mm2 to about 30 mm2 per mg of aerosol-generating film, or about 20 mm2 to about 30 mm2 per mg of aerosol-generating film.

[0044] Alternatively or additionally, the total exposed surface area of ​​the aerosol-generating film may be maximized by increasing the bulk density of the aerosol-generating film within the rod of aerosol-generating substrate, so that a larger amount of film, and therefore a larger exposed surface area, may be provided per unit volume of the rod of aerosol-generating substrate. The efficiency of delivery of the aerosol from a given volume of aerosol-generating substrate may thereby be improved. Thus, it may be possible to generate a desired amount of aerosol with an aerosol-generating substrate of reduced size.

[0045] The bulk density of the aerosol-generating film within the rod of aerosol-generating substrate is preferably at least about 100 mg per cubic centimeter of the rod of aerosol-generating substrate, more preferably at least about 200 mg per cubic centimeter of the rod of aerosol-generating substrate, more preferably at least about 300 mg per cubic centimeter of the rod of aerosol-generating substrate, and most preferably at least about 400 mg per cubic centimeter.

[0046] The bulk density of the aerosol-generating film within the rod of aerosol-generating substrate is preferably about 1000 mg per cubic centimeter or less of the rod of aerosol-generating substrate, more preferably about 850 mg per cubic centimeter or less, more preferably about 750 mg per cubic centimeter or less, and most preferably about 600 mg per cubic centimeter or less. For example, the bulk density of the aerosol-generating film within the rod of aerosol-generating substrate may be about 100 mg to about 1000 mg per cubic centimeter, or about 200 mg to about 8500 mg per cubic centimeter, or about 300 mg to about 750 mg per cubic centimeter, or about 400 mg to about 600 mg per cubic centimeter.

[0047] The bulk density of an aerosol-generating film corresponds to the total amount of film (in mg) provided on a rod of aerosol-generating substrate, not including the weight of any carrier material, divided by the total volume of the rod (in cubic centimeters).

[0048] The present invention encompasses a variety of different configurations of the aerosol-generating film to provide increased total exposed surface area.

[0049] In certain preferred embodiments, the rod of aerosol-generating substrate comprises multiple stacked layers of aerosol-generating film.

[0050] As used herein, the term "stacked" refers to the placement of multiple layers of an aerosol-generating film on top of one another. In the present invention, "stacked" layers may be placed on top of one another with a space between adjacent layers. Alternatively, adjacent layers may at least partially contact one another such that the layers are spaced apart in some areas while in other areas the space between adjacent layers approaches zero. The term "stacked" is used herein without regard to the orientation of the stacked layers.

[0051] The provision of multiple stacked layers of aerosol-generating film advantageously provides a relatively high exposed surface area of ​​the film, since the surfaces of the aerosol-generating film on both sides of each layer may be exposed, which may be readily increased by increasing the number of layers in the stack.

[0052] The ordered arrangement of the layers advantageously provides a consistent distribution of the aerosol-generating film and a consistent resistance to drawing on the rod, which can be easily controlled through adjustment of the layer spacing and layer thickness. The ordered arrangement of the layers can also optimize heat transfer from a heater element in contact with the rod during use through the rod.

[0053] Multiple layers of the aerosol-generating film may be stacked such that each layer extends along the longitudinal axis of the aerosol-generating article. Preferably, the layers are laterally spaced apart from one another to allow air flow through the rod during use. This arrangement of layers with lateral spacing between adjacent layers may facilitate the insertion of a heater element, such as a heater blade, into the rod.

[0054] In such embodiments having multiple longitudinally extending layers, preferably at least about 80 percent of the multiple layers extend substantially the entire length of the rod, more preferably at least about 90 percent of the multiple layers, more preferably at least about 95 percent of the multiple layers. Particularly preferably, each of the multiple layers extends substantially the entire length of the rod. A layer that extends substantially the entire length of the rod extends substantially the entire path between the upstream and downstream ends of the rod. Such an arrangement provides better control over the pull resistance of the rod and therefore aerosol delivery. The relative width of the multiple layers can be varied to provide various arrangements of stacked layers. For example, at least two layers can have different widths from each other. Alternatively, the multiple layers have a substantially constant width.

[0055] In such embodiments having multiple longitudinally extending layers, the multiple layers are preferably arranged substantially parallel to one another to provide substantially constant lateral spacing of the layers along the length of the rod. The lateral spacing between the layers can be tailored to provide a desired airflow level, and thus a desired rod pull-out resistance. The layers are preferably laterally spaced apart from one another by at least about 10 microns, more preferably at least about 20 microns, and most preferably at least about 50 microns. The layers are preferably laterally spaced apart from one another by no more than about 300 microns, more preferably no more than about 200 microns, and most preferably no more than about 150 microns.

[0056] Alternatively, multiple layers of aerosol-generating film may be stacked such that each layer extends laterally of the aerosol-generating article. The stack of layers thus extends along the length of the rod. The transverse layers of aerosol-generating film are adapted to permit longitudinal air flow through the rod during use. For example, each of the layers may be provided with one or more holes or cutouts therethrough.

[0057] In such embodiments having multiple lateral layers of the aerosol-generating film, the layers are preferably longitudinally spaced apart to maximize the exposed surface of the layers. In this case, the layers are preferably spaced apart from one another by at least about 50 microns, more preferably at least about 100 microns, and most preferably at least about 150 microns. The layers are preferably longitudinally spaced apart from one another by no more than about 1500 microns, more preferably no more than about 800 microns, and most preferably no more than about 600 microns. Alternatively, the layers may be stacked such that adjacent layers at least partially contact one another and have substantially no longitudinal spacing between them.

[0058] The following further discussion of embodiments of the invention involving multiple stacked layers of an aerosol-generating film applies to all arrangements of layers as described above.

[0059] The number of layers of aerosol-generating film stacked within a rod can vary depending on the thickness of the layers and the length of the rod. The number of layers can be increased to increase the total exposed surface area of ​​the aerosol-generating film. Preferably, the rod comprises from about 2 to about 50 stacked layers of aerosol-generating film.

[0060] The multiple layers of the aerosol-generating film may all have substantially the same thickness as one another, or the multiple layers may include at least two layers of different thicknesses.

[0061] In certain preferred embodiments of the invention, multiple stacked layers of the aerosol-generating film are mounted within a tubular carrier element, such as a paper or cardboard tube. In alternative embodiments, multiple stacked layers are surrounded by a wrapper. By providing the stacked layers within a tubular carrier element or wrapper, the aerosol-generating film may be more conveniently combined with other components to form an aerosol-generating article.

[0062] In an alternative embodiment of the invention, the rod of aerosol-generating substrate comprises an assemblage of one or more layers of aerosol-generating film. As used herein with respect to the present invention, the term "assemblance" refers to a layer that is coiled, folded or otherwise compressed or contracted substantially transverse to the longitudinal axis of the aerosol-generating article.

[0063] The use of an assembly of one or more layers of aerosol-generating film is an alternative method of providing a relatively high exposed surface area within the rod of aerosol-generating substrate. The exposed surface area of ​​the aerosol-generating film, and also the bulk density of the aerosol-generating film within the rod, can be easily controlled by tailoring the degree of convolution or folding of the layers.

[0064] The assembly of one or more layers of aerosol-generating film is preferably surrounded by a wrapper. The assembly of one or more layers of aerosol-generating film preferably extends along substantially the entire length of the aerosol-generating rod and across substantially the entire cross-sectional area of ​​the rod.

[0065] In a further alternative embodiment of the invention, the rod of aerosol-generating substrate comprises multiple strips or pieces of aerosol-generating film. For example, the rod may be formed from multiple strips of aerosol-generating film that are longitudinally aligned, packed together, and rolled to form the rod of aerosol-generating substrate. Alternatively, the strips of aerosol-generating film may be randomly oriented within the rod. The use of multiple strips or pieces is a further way in which the total exposed surface area of ​​the aerosol-generating film may be increased. The exposed surface area of ​​the aerosol-generating film and the bulk density of the aerosol-generating film within the rod may also be easily controlled by tailoring the number of strips within the volume of the rod.

[0066] In such embodiments, the strips of aerosol-generating film preferably have a length of from about 10 millimeters to about 20 millimeters, more preferably from about 12 millimeters to about 18 millimeters, more preferably from about 14 millimeters to about 16 millimeters, and most preferably from about 15 millimeters. Alternatively or additionally, the strips of aerosol-generating film preferably have a width of from about 0.4 millimeters to about 0.8 millimeters.

[0067] In a further embodiment of the invention, the rod of aerosol-generating substrate may comprise an aerosol-generating film, for example a plurality of hollow beads formed from a plurality of spherical beads. The use of a plurality of beads is a further way in which the total exposed surface area of ​​the aerosol-generating film may be increased. The exposed surface area of ​​the aerosol-generating film and also the bulk density of the aerosol-generating film within the rod may be easily controlled by matching the number of beads within the rod and the packing density of the beads.

[0068] A rod of aerosol-generating substrate may comprise from about 2 to about 30 beads of the aerosol-generating film. A plurality of beads are preferably provided within a cavity of a tubular carrier element such that they can be contained within the aerosol-generating substrate.

[0069] In any embodiment of the present invention, the aerosol-generating film may advantageously be textured over at least a portion of its surface. As used herein, the term "textured" refers to a film that has been crimped, embossed, debossed, perforated, or otherwise deformed. For example, the film may include a plurality of spaced apart indentations, protrusions, perforations, or a combination thereof. The texture may be provided on one side of the film, or on both sides of the film. When multiple stacked layers of the aerosol-generating film are provided, some or all of the layers may be textured.

[0070] Providing a texture on at least a portion of the surface of the aerosol-generating film is an alternative or additional way in which the exposed surface area of ​​the aerosol-generating film may be maximised.

[0071] In certain embodiments, the aerosol-generating film is crimped over at least a portion of its surface. As used herein, the term "crimped" refers to a film having a plurality of substantially parallel ridges or corrugations. Preferably, the substantially parallel ridges or corrugations extend along or parallel to the longitudinal axis of the aerosol-generating article when the article is assembled.

[0072] A single crimped layer of aerosol-generating film may be provided within the rod of aerosol-generating substrate. In such an embodiment, the single crimped layer is preferably an aggregate as described above. Alternatively, multiple crimped layers of aerosol-generating film may be provided. For example, multiple crimped layers of aerosol-generating film may be stacked to form a rod of aerosol-generating substrate as described above.

[0073] The thickness of the aerosol-generating film of the aerosol-generating article according to the invention is preferably at least about 0.05 millimeters, more preferably at least about 0.1 millimeters, and most preferably at least about 0.15 millimeters. The thickness of the aerosol-generating film is preferably about 1.0 millimeters or less, more preferably about 0.5 millimeters or less, and most preferably about 0.3 millimeters or less. For example, the thickness of the film may be about 0.05 millimeters to about 1.0 millimeters, or about 0.1 millimeters to about 0.5 millimeters, or about 0.15 millimeters to about 0.3 millimeters. Thus, the present invention provides a relatively thin layer of aerosol-generating film so that the surface area to weight ratio of the film may be maximized. This improves the efficiency of release of volatile components from the aerosol-generating film upon heating. The use of a relatively thin layer of aerosol-generating film also allows the weight of the film to be kept low while retaining sufficient surface area. This advantageously reduces the thermal inertia of the aerosol-generating film, further improving the efficiency of aerosol generation.

[0074] The weight of the aerosol-generating film on the rod of aerosol-generating substrate can also be adapted depending on the desired level of aerosol delivery during use. To minimize waste and maximize degradability of the rod of aerosol-generating substrate, the weight of the aerosol-generating film is preferably selected such that substantially all of the volatile components of the aerosol-generating film are released during a typical heating cycle of the aerosol-generating article.

[0075] The tubular carrier element preferably provides at least about 20 milligrams of aerosol-generating film, more preferably at least about 50 milligrams, more preferably at least about 100 milligrams. The tubular carrier element preferably provides no more than about 300 milligrams, more preferably no more than about 200 milligrams of aerosol-generating film. For example, the tubular carrier element may provide from about 20 milligrams to about 300 milligrams of aerosol-generating film, or from about 50 milligrams to about 200 milligrams of aerosol-generating film, or from about 100 milligrams to about 200 milligrams of aerosol-generating film.

[0076] The aerosol-generating film preferably has a basis weight of at least about 100 grams per square meter, more preferably at least about 120 grams per square meter, and most preferably at least about 140 grams per square meter. The aerosol-generating film preferably has a basis weight of 300 grams per square meter or less, more preferably has a basis weight of 280 grams per square meter or less, and most preferably has a basis weight of 260 grams per square meter or less. For example, the aerosol-generating film may have a basis weight of about 100 grams per square meter to about 300 grams per square meter, or about 120 grams per square meter to about 280 grams per square meter, or about 140 grams per square meter to about 260 grams per square meter.

[0077] The rod of aerosol-generating substrate preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article.

[0078] The aerosol-generating substrate rod preferably has an outer diameter of at least 5 millimeters. The aerosol-generating substrate rod may have an outer diameter of from about 5 millimeters to about 12 millimeters, for example from about 5 millimeters to about 10 millimeters, or from about 6 millimeters to about 8 millimeters. In one preferred embodiment, the aerosol-generating substrate rod has an outer diameter of about 7 millimeters.

[0079] The rod of the aerosol-generating substrate may have a length of about 5 millimeters to about 15 millimeters. In one embodiment, the rod of the aerosol-generating substrate may have a length of about 10 millimeters. In a preferred embodiment, the rod of the aerosol-generating substrate has a length of about 12 millimeters.

[0080] The rod of aerosol-generating substrate preferably has a substantially uniform cross-section along the length of the rod, and it is particularly preferred that the rod of aerosol-generating substrate has a substantially circular cross-section.

[0081] The aerosol-generating film may be incorporated directly into the rod of aerosol-generating substrate as a single layer substrate. The single layer aerosol-generating film may be textured as described above. Alternatively, the aerosol-generating film may be coated or impregnated onto a carrier layer, such as a layer of porous or fibrous sheet material, prior to incorporation into the rod of aerosol-generating substrate. Suitable sheet materials for the carrier layer include, but are not limited to, paper, cardboard, and homogenized plant material. The carrier layer with the aerosol-generating film may be textured as described above.

[0082] The aerosol-generating film of the aerosol-generating article according to the present invention has a composition comprising at least about 25 weight percent polyhydric alcohol, more preferably at least about 30 weight percent polyhydric alcohol, more preferably at least about 35 weight percent polyhydric alcohol, and more preferably at least about 40 weight percent polyhydric alcohol.

[0083] Preferably, the aerosol-generating film contains less than about 90 weight percent polyhydric alcohol, more preferably less than about 80 weight percent polyhydric alcohol, more preferably less than about 70 weight percent polyhydric alcohol, more preferably less than about 60 weight percent polyhydric alcohol.

[0084] For example, the aerosol-generating film can contain from about 25 weight percent to about 90 weight percent polyhydric alcohol, or from about 30 weight percent to about 80 weight percent polyhydric alcohol, or from about 35 weight percent to about 70 weight percent polyhydric alcohol, or from about 40 weight percent to about 60 weight percent polyhydric alcohol.

[0085] Polyhydric alcohols suitable for use in the aerosol-generating films include, but are not limited to, propylene glycol, triethylene glycol, 1,3-butanediol, and glycerin. In the aerosol-generating films according to the present invention, the polyhydric alcohol is preferably selected from the group consisting of glycerin, propylene glycol, and combinations thereof. In a particularly preferred embodiment, the polyhydric alcohol is glycerin.

[0086] The present invention therefore advantageously provides films having significant polyhydric alcohol content that can be easily cast or extruded and solidified, starting from a composition having a gel-like texture. Because a significant proportion of the polyhydric alcohol, particularly glycerin, can be provided in film form, while at the same time allowing fine control over the shape of the film, the present invention advantageously provides films that are particularly suitable for use with aerosol-generating substrates in aerosol-generating articles designed to emit an aerosol upon heating.

[0087] The aerosol-generating film further preferably comprises at least about 3 weight percent cellulosic film former, more preferably at least about 6 weight percent cellulosic film former, more preferably at least about 10 weight percent cellulosic film former, more preferably at least about 14 weight percent cellulosic film former, more preferably at least about 16 weight percent cellulosic film former, and more preferably at least about 18 weight percent cellulosic film former.

[0088] The aerosol-generating film may comprise up to about 70 weight percent cellulosic film former. Preferably, the aerosol-generating film comprises no more than about 26 weight percent cellulosic film former, more preferably no more than about 24 weight percent cellulosic film former, and even more preferably no more than about 22 weight percent cellulosic film former.

[0089] For example, the aerosol-generating film can include from about 3 weight percent to about 70 weight percent of the cellulosic film former, or from about 6 weight percent to about 26 weight percent of the cellulosic film former, or from about 10 weight percent to about 24 weight percent of the cellulosic film former, or from about 14 weight percent to about 24 weight percent of the cellulosic film former, or from about 16 weight percent to about 22 weight percent of the cellulosic film former, or from about 18 weight percent to about 22 weight percent of the cellulosic film former.

[0090] In the context of the present invention, the term "cellulosic film former" is used to describe a cellulosic polymer that has the ability to form a continuous film by itself, or in the presence of an auxiliary thickener.

[0091] Preferably, the cellulosic film former is selected from the group consisting of hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), ethylcellulose (EC), hydroxyethyl methylcellulose (HEMC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), and combinations thereof. In a particularly preferred embodiment, the cellulosic film former is HPMC.

[0092] In the aerosol-generating film, the ratio between the weight of the cellulosic film former and the weight of the polyhydric alcohol is preferably at least about 0.1, more preferably at least about 0.2, and even more preferably at least about 0.3. Additionally or alternatively, in the aerosol-generating film, the ratio between the weight of the cellulosic film former and the weight of the polyhydric alcohol is preferably about 1 or less.

[0093] In a preferred embodiment, the aerosol-generating film has a ratio between the weight of the cellulosic film-forming agent and the weight of the polyhydric alcohol of from about 0.1 to about 1.

[0094] The inventors have surprisingly found that aerosol-generating films comprising at least 6 percent by weight of a cellulosic film former, and preferably HPMC, are particularly stable. Thus, they substantially maintain their shape when exposed to a variety of environmental conditions, such as relative humidity changes from 10 percent to 60 percent. As a result, such aerosol-generating films advantageously do not release a liquid phase during storage or transportation.

[0095] The aerosol-generating film further preferably comprises at least about 1 weight percent of a non-cellulosic thickener, more preferably at least about 2 weight percent of a non-cellulosic thickener, and even more preferably at least about 3 weight percent of a non-cellulosic thickener. The aerosol-generating film preferably comprises no more than about 10 weight percent of a non-cellulosic thickener, more preferably no more than about 8 weight percent of a non-cellulosic thickener, and even more preferably no more than about 6 weight percent of a non-cellulosic thickener. For example, the aerosol-generating film may comprise from about 1 weight percent to about 10 weight percent of a non-cellulosic thickener, or from about 2 weight percent to about 8 weight percent of a non-cellulosic thickener, or from about 3 weight percent to about 6 weight percent of a non-cellulosic thickener.

[0096] As used herein in connection with the present invention, the term "non-cellulosic thickener" is used to describe a non-cellulosic material that, when added to an aqueous or non-aqueous liquid composition, increases the viscosity of the liquid composition without substantially altering other properties of the liquid composition. Thickeners can increase the stability and improve the suspension of ingredients in the liquid composition. Thickeners can also be called "thickeners" or "rheology modifiers."

[0097] In the aerosol-generating film according to the invention, the non-cellulosic thickener is preferably selected from the group consisting of agar, xanthan gum, gum arabic, guar gum, locust bean gum, pectin, carrageenan, starch, alginate, and combinations thereof. In a preferred embodiment, the non-cellulosic thickener is agar.

[0098] In the aerosol-generating film, the ratio between the weight of the non-cellulosic thickener and the weight of the polyhydric alcohol is preferably at least about 0.05, more preferably at least 0.1, and even more preferably at least 0.2. Additionally or alternatively, in the aerosol-generating film, the ratio between the weight of the non-cellulosic thickener and the weight of the polyhydric alcohol is preferably no greater than about 0.5.

[0099] In a preferred embodiment, in the aerosol-generating film, the ratio between the weight of the non-cellulosic thickener and the weight of the polyhydric alcohol is from about 0.1 to about 0.5.

[0100] The inventors have surprisingly found that by incorporating a combination of a cellulosic film former and a non-cellulosic thickener, along with a polyhydric alcohol, into a film, they can provide a film with improved stability that can be produced with high precision and reproducibility.

[0101] Preferably, the aerosol-generating film contains less than about 30 percent water by weight, and more preferably, the aerosol-generating film contains between about 10 percent and about 20 percent water by weight.

[0102] In some embodiments, the aerosol-generating film further comprises an alkaloid compound or a cannabinoid compound, or both.

[0103] The term "alkaloid compound" as used herein in connection with the present invention means any one of a class of naturally occurring organic compounds that contain one or more basic nitrogen atoms. Generally, alkaloids contain at least one nitrogen atom in an amine-type structure. This nitrogen atom or another nitrogen atom in the molecule of the alkaloid compound may be active as a base in an acid-base reaction. Most alkaloid compounds have one or more of their nitrogen atoms as part of a ring system, such as a heterocyclic ring. In nature, alkaloid compounds are found primarily in plants, especially common in certain families of flowering plants. However, some alkaloid compounds are found in animal species and fungi. In the context of the present invention, the term "alkaloid compound" is used to describe both naturally occurring and synthetically produced alkaloid compounds.

[0104] Preferably, the alkaloid compound is selected from the group consisting of nicotine, anatabine and combinations thereof.

[0105] As used herein with respect to the present invention, the term "cannabinoid compounds" describes any one of a class of naturally occurring compounds found in parts of the cannabis plant, i.e., Cannabis sativa, Cannabis indica, and Cannabis ruderalis. Cannabinoid compounds are particularly concentrated in the female flower heads. Naturally occurring cannabinoid compounds in the cannabis plant include tetrahydrocannabinol (THC) and cannabidiol (CBD). In the context of the present invention, the term "cannabinoid compounds" is used to describe both naturally occurring and synthetically produced cannabinoid compounds.

[0106] Preferably, the gel comprises a cannabinoid compound selected from the group consisting of tetrahydrocannabinol (THC), tetrahydrocannabinolic acid (THCA), cannabidiol (CBD), cannabidiol acid (CBDA), cannabinol (CBN), cannabigerol (CBG), cannabigerol monomethyl ether (CBGM), cannabivarin (CBV), cannabidivarin (CBDV), tetrahydrocannabivarin (THCV), cannabichromene (CBC), cannabicyclol (CBL), cannabichromevarin (CBCV), cannabigerovarin (CBGV), cannabielsoin (CBE), cannabicitran (CBT), and combinations thereof.

[0107] In general, aerosol-generating films can contain up to about 10 weight percent of alkaloid compounds or cannabinoid compounds, or both. The content of alkaloid compounds or cannabinoid compounds, or both, in the film can be increased and adjusted in view of optimizing the delivery of alkaloid compounds or cannabinoid compounds, or both, to consumers in aerosol form. Compared to existing aerosol-generating substrates based on the use of plant materials, this can advantageously allow for a higher content of alkaloid compounds or cannabinoid compounds, or both, per substrate (film) volume or per substrate (film) weight, which can be desirable from a manufacturing standpoint.

[0108] The aerosol-generating film preferably comprises at least about 0.5 weight percent of an alkaloid compound or a cannabinoid compound, or both.Thus, the aerosol-generating film preferably comprises at least about 0.5 weight percent of an alkaloid compound, or at least 0.5 weight percent of a cannabinoid compound, or at least about 0.5 weight percent of a combination of an alkaloid compound and a cannabinoid compound.

[0109] The aerosol-generating film preferably contains at least about 1 weight percent alkaloid and / or cannabinoid compounds, more preferably at least about 2 weight percent alkaloid and / or cannabinoid compounds, preferably less than about 6 weight percent alkaloid and / or cannabinoid compounds, more preferably less than about 5 weight percent alkaloid and / or cannabinoid compounds, and more preferably less than about 4 weight percent alkaloid and / or cannabinoid compounds.

[0110] For example, the aerosol-generating film may contain from about 0.5 weight percent to about 10 weight percent of an alkaloid compound or cannabinoid compound, or both, or from about 1 weight percent to about 6 weight percent of an alkaloid compound or cannabinoid compound, or both, or from about 2 weight percent to about 5 weight percent of an alkaloid compound or cannabinoid compound, or both.

[0111] In some embodiments, the aerosol-generating film comprises one or more of a cannabinoid and an alkaloid compound, including nicotine or anatabine. In some preferred embodiments, the aerosol-generating film comprises nicotine. As used herein in connection with the present invention, the term "nicotine" is used to describe nicotine, nicotine base, or nicotine salts. In embodiments where the aerosol-generating film comprises nicotine base or nicotine salts, the amount of nicotine recited herein is the amount of free base nicotine or the amount of protonated nicotine, respectively.

[0112] The aerosol-generating film may contain natural or synthetic nicotine.

[0113] The aerosol-generating film may include one or more monobasic nicotine salts.

[0114] As used herein in connection with the present invention, the term "monobasic nicotine salt" is used to describe nicotine salts of monobasic acids.

[0115] Preferably, the aerosol-generating film comprises at least about 0.5 weight percent nicotine. More preferably, the aerosol-generating film comprises at least about 1 weight percent nicotine. Even more preferably, the aerosol-generating film comprises at least about 2 weight percent nicotine. Additionally or alternatively, the aerosol-generating film preferably comprises less than about 10 weight percent nicotine. More preferably, the aerosol-generating film comprises less than about 6 weight percent nicotine. Even more preferably, the aerosol-generating film comprises less than about 5 weight percent nicotine. For example, the aerosol-generating film may comprise between about 0.5 weight percent and about 10 weight percent nicotine, or between about 1 weight percent and about 6 weight percent nicotine, or between about 2 weight percent and about 5 weight percent nicotine.

[0116] In some preferred embodiments, the aerosol-generating film comprises a cannabinoid compound. Preferably, the cannabinoid compound is selected from CBD and THC. More preferably, the cannabinoid compound is CBD.

[0117] The aerosol-generating film may contain up to about 10 weight percent CBD. Preferably, the aerosol-generating film contains at least about 0.5 weight percent CBD, more preferably at least about 1 weight percent CBD, and even more preferably at least about 2 weight percent CBD. Preferably, the aerosol-generating film contains less than about 6 weight percent CBD, more preferably less than about 5 weight percent CBD, and even more preferably less than about 4 weight percent CBD.

[0118] For example, the aerosol-generating film may contain from about 0.5 weight percent to about 10 weight percent CBD, more preferably from about 1 weight percent to about 6 weight percent CBD, and even more preferably from about 2 weight percent to about 5 weight percent CBD.

[0119] The aerosol-generating film may be a substantially tobacco-free aerosol-generating film.

[0120] As used herein in connection with the present invention, the term "substantially tobacco-free aerosol-generating film" describes an aerosol-generating film having a tobacco content of less than 1 weight percent. For example, the aerosol-generating film may have a tobacco content of less than about 0.75 weight percent, less than about 0.5 weight percent, or less than about 0.25 weight percent.

[0121] The aerosol-generating film may be a tobacco-free aerosol-generating film.

[0122] As used herein in connection with the present invention, the term "tobacco-free aerosol-generating film" describes an aerosol-generating film that has zero percent tobacco content by weight.

[0123] In some embodiments, the aerosol-generating film comprises tobacco material or non-tobacco plant material or plant extract. As an example, the aerosol-generating film may comprise tobacco particles, such as tobacco lamina particles, as well as particles of other plants, such as cloves and eucalyptus. When the aerosol-generating film comprises tobacco, the tobacco content is preferably about 70 weight percent or less, more preferably about 50 weight percent or less, more preferably about 30 weight percent or less, and most preferably about 10 weight percent or less.

[0124] In a preferred embodiment, the aerosol-generating film comprises an acid. More preferably, the aerosol-generating film comprises one or more organic acids. Even more preferably, the aerosol-generating film comprises one or more carboxylic acids. In a particularly preferred embodiment, the acid is lactic acid or levulinic acid.

[0125] The inclusion of an acid is particularly preferred in the embodiment of the aerosol-generating film that includes nicotine. This is because it has been observed that the presence of an acid can stabilize species dissolved in the film-forming composition, such as nicotine and other plant extracts. Without wishing to be bound by theory, it is understood that when nicotine is provided in a salt form, the acid can interact with the nicotine molecule, which substantially prevents nicotine from evaporating during the drying operation. Therefore, the loss of nicotine during the production of the film can be minimized, and advantageously, a higher and more controlled nicotine delivery to the consumer can be ensured.

[0126] Preferably, the aerosol-generating film comprises at least about 0.25 weight percent acid. More preferably, the aerosol-generating film comprises at least about 0.5 weight percent acid. Even more preferably, the aerosol-generating film comprises at least about 1 weight percent acid. Additionally or alternatively, the aerosol-generating film preferably comprises less than about 3.5 weight percent acid. More preferably, the aerosol-generating film comprises less than about 3 weight percent acid. Even more preferably, the aerosol-generating film comprises less than about 2.5 weight percent acid.

[0127] For example, the aerosol-generating film can include from about 0.25 weight percent to about 3.5 weight percent acid, or from about 0.5 weight percent to about 3 weight percent acid, or from about 1 weight percent to about 2.5 weight percent acid.

[0128] The aerosol-generating film may optionally include a flavoring agent. In some embodiments, the aerosol-generating film may include up to about 2 weight percent of a flavoring agent. By way of example, the aerosol-generating film may include menthol, terpene, terpenoid, eugenol, or eucalyptol.

[0129] The aerosol-generating film may be produced by forming a film-forming composition of the components of the film, preferably an aqueous film-forming composition, casting or extruding the film-forming composition onto a support surface, allowing the film-forming composition to gel, and then drying the film-forming composition to obtain an aerosol-generating film. The film may then be removed from the support surface and incorporated into an aerosol-generating substrate for an aerosol-generating article. Alternatively, the film may be incorporated into an aerosol-generating substrate along with a support surface.

[0130] It has been found that upon heating, most of the components of the aerosol-generating film evaporate.In fact, it has been observed that, if present, typically only some residue of the cellulosic film former remains after use.Therefore, an aerosol-generating article incorporating a substrate comprising the above-mentioned aerosol-generating film can be easily disposed of and have improved environmental impact.

[0131] During use, the aerosol-generating film may be heated to a temperature of about 180 degrees Celsius to about 250 degrees Celsius to generate an aerosol. The inventors have surprisingly found that the aerosol-generating film, when heated in an aerosol generating device, can release the polyhydric alcohol without substantially releasing the liquid phase.

[0132] Aerosol-generating articles according to the invention preferably comprise one or more elements in addition to a rod of aerosol-generating substrate, the rod and the one or more elements being assembled within a substrate wrapper or within a tubular carrier element.

[0133] The aerosol-generating article preferably further comprises a flow restricting element downstream of the rod of the aerosol-generating substrate. The flow restricting element may be advantageously incorporated to provide the aerosol-generating article with an acceptable level of resistance to draw (RTD). Suitable flow restricting elements for providing a desired level of RTD are known to those skilled in the art. In some embodiments, the flow restricting element may be a constriction, such as one or more holes, having a diameter smaller than the diameter of the internal cavity. In a preferred embodiment, the flow restricting element comprises one or more plugs of fibrous filtration material, such as one or more plugs of cellulose acetate.

[0134] The resistance to draw (RTD) of the aerosol-generating article after insertion of the heater element is preferably from about 40 mmWG to about 140 mmWG, more preferably from about 80 mmWG to about 120 mmWG.

[0135] As used herein, withdrawal resistance is expressed in pressure units "mmWG" or "Millimeters of Water Column" and is measured in accordance with ISO 6565:2002.

[0136] The flow restricting element may extend to the downstream end of the aerosol-generating article. Alternatively, a hollow mouth end cavity may be provided downstream of the flow restricting element.

[0137] Preferably, the flow restricting element extends longitudinally along the aerosol-generating article from about 15 millimeters to about 25 millimeters.

[0138] The flow restricting element is preferably longitudinally spaced from the aerosol-generating substrate such that the flow restricting element and the rod of the aerosol-generating substrate are separated by a hollow space or cavity. Such separation of components advantageously provides space for the formation of an aerosol within the aerosol-generating article. The longitudinal spacing between the flow restricting element and the aerosol-generating film is preferably at least about 10 percent of the length of the aerosol-generating article, more preferably at least about 20 percent of the length. The length of the space between the aerosol-generating film and the flow restricting element is preferably at least 50 percent of the length of the rod of the aerosol-generating substrate.

[0139] Preferably, the aerosol-generating article further comprises an upstream sealing element covering the upstream end of the rod of aerosol-generating substrate. The sealing of the upstream end advantageously reduces the ingress of air and water into the rod of aerosol-generating substrate prior to use. This helps maintain the freshness of the aerosol-generating film during storage to optimize the delivery of aerosols upon heating. Furthermore, the sealing of the upstream end of the rod of aerosol-generating substrate may reduce the loss of volatile components of the aerosol-generating film during storage, maximizing the delivery of these components to the consumer.

[0140] The upstream sealing element may take any suitable form, but is preferably in the form of a sheet of material that covers the upstream face of the rod of the aerosol-generating substrate. The sheet of material is preferably substantially impermeable. The upstream sealing element may be formed of any suitable sheet material, including, but not limited to, paper, aluminum, polymer, or combinations thereof.

[0141] A frangible upstream sealing element is preferably provided, the sealing element being frangible so that it may be penetrated by a heater element or other piercing means upon insertion of the aerosol-generating article into the aerosol-generating device. A support element, such as a plug of fibrous filtration material, may be provided immediately behind the frangible upstream sealing element, if desired, to facilitate penetration of the frangible upstream sealing element by a heater element or other piercing means.

[0142] Alternatively or in addition to the upstream sealing element, the aerosol-generating article may further comprise a downstream sealing element at its downstream end. The downstream sealing element may be of the same or different form as the upstream sealing element. If a downstream sealing element is provided, it may be removable so that it can be removed from the aerosol-generating article prior to use.

[0143] Alternatively or additionally to the provision of an upstream sealing element, a tubular support element may be provided at the upstream end of the aerosol-generating article, upstream of the rod of the aerosol-generating substrate. For example, a hollow acetate tube may be provided at the upstream end of the aerosol-generating article, upstream of the rod of the aerosol-generating substrate. The tubular support element may advantageously minimize the risk of the aerosol-generating film being lost from the aerosol-generating article prior to use. Furthermore, the tubular support element may facilitate the insertion and removal of the internal heater element into and from the aerosol-generating article during use of the aerosol-generating article in an aerosol-generating device. Furthermore, the tubular support element may be used to direct or control airflow through the aerosol-generating article.

[0144] The third and fourth aspects of the invention provide a rod for use as an aerosol-generating substrate for an aerosol-generating article, the rod comprising an aerosol-generating film, as defined above. The aerosol-generating substrate rod and the aerosol-generating film may have any of the features or characteristics described above in relation to the first and second aspects of the invention.

[0145] As mentioned above, a rod of aerosol-generating substrate according to the third aspect of the invention may be produced using a method according to the invention, as defined below. The method comprises a first step of providing an aqueous film-forming composition comprising a polyhydric alcohol and a cellulosic film former, and a second step of providing a sheet material. In a third step, the aqueous film-forming composition is applied onto a surface of the sheet material to form a film layer, and in a fourth step, the film layer is dried to form an aerosol-generating film having at least 25 weight percent of the polyhydric alcohol and at least 10 weight percent of the cellulosic film former. In a fifth step, the film layer is configured to form a rod of aerosol-generating substrate such that the exposed surface area of ​​the aerosol-generating film is at least about 5 square millimeters per milligram of aerosol-generating film.

[0146] As mentioned above, a rod of aerosol-generating substrate according to the fourth aspect of the invention may be produced using a method according to the invention, as defined below. The method comprises a first step of providing an aqueous film-forming composition comprising a polyhydric alcohol and a cellulosic film-forming agent, and a second step of providing a sheet material. In a third step, the aqueous film-forming composition is applied onto a surface of the sheet material to form a film layer, and in a fourth step, the film layer is dried to form an aerosol-generating film having at least about 40 weight percent of the polyhydric alcohol and at least about 10 weight percent of the cellulosic film-forming agent. In a fifth step, the film layer is configured to form a rod of aerosol-generating substrate such that the bulk density of the aerosol-generating film is at least about 100 mg per cubic centimeter of rod of aerosol-generating substrate.

[0147] In any method according to the invention, the configuring step will depend on the desired configuration of the aerosol-generating film within the rod of aerosol-generating substrate. For example, as described above, if it is desired to form a rod of aerosol-generating substrate comprising multiple stacked layers of aerosol-generating film, the configuring step of the aerosol-generating film may comprise forming multiple layers of aerosol-generating film and stacking the multiple layers to form a rod. Alternatively, the configuring step of the aerosol-generating film may comprise assembling the aerosol-generating film to form a rod. Alternatively, the configuring step of the aerosol-generating film may comprise cutting multiple strips from a film layer and forming the multiple strips into a rod.

[0148] As mentioned above, the present invention further provides an aerosol generation system comprising an aerosol-generating article comprising a rod of aerosol-generating substrate according to the present invention in combination with an electrically operated aerosol generating device adapted to receive the aerosol-generating article and having a heater element configured to heat the aerosol-generating film of the rod of aerosol-generating substrate, the aerosol-generating article comprising an aerosol-generating substrate according to the third or fourth aspect of the present invention as detailed above.

[0149] The heater element is preferably configured to heat the aerosol-generating film to a temperature of about 120 degrees Celsius to about 350 degrees Celsius, more preferably about 200 degrees Celsius to about 220 degrees Celsius.

[0150] An electrically operated aerosol generating device may be configured to externally heat an aerosol-generating article: An elongated heating chamber adapted to receive the aerosol-generating article is provided, and heater elements are provided circumferentially around the heating chamber to partially or completely surround the aerosol-generating article within the chamber, such that a rod of the aerosol-generating substrate is heated.

[0151] Alternatively, the electrically operated aerosol generating device may be configured to internally heat the aerosol-generating article from within the tubular carrier element. A heater element in the form of an elongated heater blade or pin is provided which is adapted to be inserted into the rod of the aerosol-generating substrate to heat the aerosol-generating film.

[0152] In any of the aerosol generating systems according to the invention, the heater element may be of any suitable form for conducting heat. The aerosol generating system may be an electrically operated aerosol generating system with an induction heating device. The induction heating device generally comprises an induction source configured to be coupled to the susceptor. The induction source generates an alternating electromagnetic field, which induces magnetization or eddy currents in the susceptor. The susceptor may heat as a result of hysteresis losses or induced eddy currents, which heat the susceptor through ohmic or resistive heating.

[0153] The electrically operated aerosol generating system with an induction heating device also includes an aerosol-generating article having an aerosol-generating film and a susceptor in thermal proximity to the aerosol-generating film. The susceptor is heated through hysteresis losses or induced eddy currents, which in turn heats the aerosol-generating film. Typically, the susceptor is in direct contact with the aerosol-generating film, and heat is transferred from the susceptor to the aerosol-generating film primarily by conduction. Examples of electrically operated aerosol generating systems with an induction heating device and an aerosol-generating article with a susceptor are described in WO-A1-95 / 27411 and WO-A1-2015 / 177255.

[0154] The invention will now be further described with reference to the figures. [Brief description of the drawings]

[0155] [Figure 1] FIG. 1 shows a schematic longitudinal cross-section of an aerosol-generating article according to a first embodiment of the invention. [Diagram 2]FIG. 2 shows a schematic longitudinal cross-sectional view of the aerosol-generating article of FIG. 1 in combination with an internal heater element of an aerosol-generating device. [Diagram 3] FIG. 3 shows a schematic longitudinal cross-sectional view of the aerosol-generating article of FIG. 1 in combination with an external heater element of an aerosol-generating device. [Figure 4] FIG. 4 shows a schematic longitudinal cross-section of an aerosol-generating article according to a second embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0156] The aerosol-generating article 10 shown in FIG. 1 comprises a tubular carrier element 12 , an aerosol-generating substrate 14 and a flow restricting element 16 .

[0157] The tubular carrier element 12 is in the form of a cardboard tube having a length of approximately 12 millimeters and an outer diameter of approximately 7 millimeters. The tubular carrier element 12 is cylindrical in shape and defines a longitudinally extending interior cavity 18 that extends from an upstream end 20 to a downstream end 22 of the tubular carrier element 12.

[0158] The rod of aerosol-generating substrate 14 includes multiple layers 24 of aerosol-generating film. As shown in FIG. 1, each of the multiple layers 24 extends longitudinally along the entire length of the rod 14. Although not shown in FIG. 1, the layers 24 are laterally spaced apart from one another. Each of the layers 24 has a thickness of approximately 0.25 millimeters and a length of approximately 10 millimeters. The rod contains about 30 sheets. The total amount of aerosol-generating film in the rod 14 is approximately 200 mg.

[0159] The exposed surface area of ​​layer 24 of the aerosol-generating film is greater than 5 square millimeters per milligram of aerosol-generating film.

[0160] The bulk density of the aerosol-generating film within the rod 14 is greater than 100 mg per cubic centimeter of the rod 14 .

[0161] The aerosol-generating film 14 has the following composition: [Table 1]

[0162] The flow restricting element 16 comprises a single segment of cellulose acetate tow at its downstream end 22 that is provided within the interior cavity 18 of the tubular carrier element 12. The flow restricting element 16 has a length of approximately 20 millimeters and an outer diameter that corresponds to the diameter of the interior cavity 18 of the tubular carrier element 12. The flow restricting element 16 is downstream of the aerosol-generating film 14 and is spaced from the aerosol-generating film 14 such that an empty space is defined within the tubular carrier element 12 between the downstream end of the aerosol-generating film 14 and the upstream end of the flow restricting element 16.

[0163] The upstream end 20 of the tubular carrier element 12 is sealed by an upstream sealing element 26 which comprises an aluminum sheet provided over the end of the tubular carrier element 12 to seal the upstream end of the internal cavity 18 .

[0164] The aerosol-generating article 10 shown in FIG. 1 is particularly suitable for use in an electrically operated aerosol-generating device that includes a heater for heating the aerosol-generating film 14 .

[0165] 2 shows a schematic diagram of an aerosol-generating article 10 being heated in an aerosol-generating device 50 having a heater blade 52. The aerosol-generating article is inserted into the aerosol-generating device 50 such that the heater blade 52 penetrates the upstream sealing element 24 and is inserted into the rod of aerosol-generating substrate 14 between the layers of the aerosol-generating film 24.

[0166] In use, the heater blade 52 heats the layer 24 of aerosol-generating film to a temperature sufficient to generate an aerosol from the aerosol-generating film. The aerosol is drawn through the flow restricting element 16 and exits through the downstream end 22 of the tubular carrier element.

[0167] 3 shows a schematic diagram of an aerosol-generating article 10 being heated in an alternative aerosol-generating device 60 having a heating chamber 62 into which the upstream end of the aerosol-generating article is inserted such that an external heater element 64 surrounds the upstream portion of the tubular carrier element 12 incorporating the rod of aerosol-generating substrate 14. The heater element 64 heats the layer of aerosol-generating film 24 within the rod of aerosol-generating substrate 14 circumferentially from the outside of the tubular carrier element 12.

[0168] The aerosol-generating device 60 further comprises a piercing element 66 that pierces the upstream sealing element 24 when the aerosol-generating article 10 is inserted into the heating chamber 62 .

[0169] FIG. 4 shows an aerosol-generating article 70 according to a second embodiment of the invention, which includes a rod of aerosol-generating substrate 74 similar in configuration to the aerosol-generating article 10 shown in FIG. 1, but with a different configuration of aerosol-generating film.

[0170] The rod 74 includes multiple layers 76 of aerosol-generating film. As shown in FIG. 4, each of the layers 76 of aerosol-generating film extends in a transverse direction. The layers 76 are parallel to one another and are stacked such that adjacent layers contact one another and have no longitudinal spacing between them. The layers 76 are circular and have a diameter that substantially corresponds to the diameter of the interior cavity 18 of the tubular carrier element 12. Each of the layers 76 has a thickness of approximately 0.25 millimeters, and the rod contains approximately 45 layers. The length of the rod 74 is approximately 5 millimeters. The total amount of aerosol-generating film in the rod 74 is approximately 200 mg.

[0171] The exposed surface area of ​​layer 76 of the aerosol-generating film is greater than 5 square millimeters per milligram of aerosol-generating film.

[0172] The bulk density of the aerosol-generating film within rod 74 is greater than 100 mg per cubic centimeter of rod 74 .

[0173] Each of the layers 76 includes a plurality of air flow holes (not shown) disposed on a surface thereof which provides the layers 76 with sufficient porosity to permit air flow through the rods 74 during use.

[0174] The aerosol-generating article 70 may be heated in an aerosol-generating device as described above with respect to the aerosol-generating article 10 .

[0175] Of course, the aerosol-generating article 10 shown in FIG. 1 may also be suitable for use in other types of aerosol-generating devices.

Claims

1. 1. An aerosol-generating article comprising a rod of an aerosol-generating substrate, the rod of the aerosol-generating substrate comprising:

1. An aerosol-generating article comprising an aerosol-generating film comprising at least 25 percent by weight of a polyhydric alcohol and at least 10 percent by weight of a cellulosic film-forming agent, the aerosol-generating film being configured such that an exposed surface area of ​​the aerosol-generating film within the aerosol-generating substrate is at least 5 square millimeters per milligram of the aerosol-generating film, the aerosol-generating film being substantially free of tobacco.

2. 1. An aerosol-generating article comprising a rod of an aerosol-generating substrate, the rod of the aerosol-generating substrate comprising:

1. An aerosol-generating article comprising an aerosol-generating film comprising at least 25 percent by weight of a polyhydric alcohol and at least 10 percent by weight of a cellulosic film-forming agent, the aerosol-generating film being configured such that the bulk density of the aerosol-generating film is at least 100 mg per cubic centimeter of the rod of the aerosol-generating substrate, the aerosol-generating film being substantially free of tobacco.

3. 3. An aerosol-generating article according to claim 1 or 2, wherein the rod of aerosol-generating substrate comprises a plurality of stacked layers of the aerosol-generating film.

4. 4. The aerosol-generating article of claim 3, wherein the layers of the aerosol-generating film are stacked such that each layer extends in a transverse direction of the aerosol-generating article.

5. 4. The aerosol-generating article of claim 3, wherein the layers of the aerosol-generating film are stacked such that each layer extends along a longitudinal axis of the aerosol-generating article.

6. 6. An aerosol-generating article according to any one of claims 3 to 5, wherein the aerosol-generating substrate comprises a tubular carrier element defining a longitudinally extending internal channel, the plurality of stacked layers being provided within the internal channel.

7. 7. An aerosol-generating article according to any one of claims 3 to 6, wherein the plurality of stacked layers of the aerosol-generating film comprises from 2 to 50 stacked layers.

8. 3. An aerosol-generating article according to claim 1 or 2, wherein the rod of aerosol-generating substrate comprises an assembly of one or more sheets of the aerosol-generating film.

9. 3. An aerosol-generating article according to claim 1 or 2, wherein the rod of aerosol-generating substrate comprises a plurality of strips of the aerosol-generating film.

10. 10. An aerosol-generating article according to claim 1, wherein the aerosol-generating film has a thickness of from 0.1 millimeters to 0.5 millimeters.

11. 11. The aerosol-generating article according to claim 1, wherein the aerosol-generating film is textured.

12. An aerosol-generating article according to any preceding claim, wherein the aerosol-generating film is provided on at least one surface of a carrier layer.

13. 1. A rod for use as an aerosol-generating substrate in an aerosol-generating article, said rod comprising:

1. An aerosol-generating article comprising an aerosol-generating film comprising at least 25 percent by weight of a polyhydric alcohol and at least 10 percent by weight of a cellulose film-forming agent, the aerosol-generating film being configured such that an exposed surface area of ​​the aerosol-generating film within the aerosol-generating substrate is at least 5 square millimeters per milligram of the aerosol-generating film, the aerosol-generating film being substantially free of tobacco.

14. 1. A rod for use as an aerosol-generating substrate in an aerosol-generating article, said rod comprising:

1. A rod comprising an aerosol-generating film comprising at least 25 percent by weight of a polyhydric alcohol and at least 10 percent by weight of a cellulosic film-forming agent, the aerosol-generating film being configured such that the bulk density of the aerosol-generating film is at least 100 mg per cubic centimeter of the rod of aerosol-generating substrate, the aerosol-generating film being substantially free of tobacco.

15. 1. An aerosol generating system comprising an electrically operated aerosol generating device including an aerosol-generating article and a heater element configured to heat an aerosol-generating substrate of the aerosol-generating article, The aerosol-generating article comprises a rod of an aerosol-generating substrate according to claim 13 or 14, an aerosol-generating system, wherein the heater element is a heater blade or heater pin configured to be inserted into a rod of the aerosol-generating substrate to heat the aerosol-generating film;

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