Aerosol-generating article comprising a composite susceptor assembly - Patents.com

Abstract

An aerosol-generating article (10) for generating an inhalable aerosol upon heating is provided, the aerosol-generating article including a susceptor assembly (100). The susceptor assembly includes at least one strand (102) of susceptor material, the at least one strand (102) of susceptor material twisted to lie helically about a longitudinal axis of the susceptor assembly (100). The susceptor assembly (100) further includes an aerosol-generating element including at least one strand (104) of porous non-tobacco material carrying an aerosol-forming composition comprising at least 35 weight percent aerosol formers. The at least one strand of the aerosol-generating element is twisted with the at least one strand (102) of susceptor material.

Description

[Technical field]

[0001] The present invention relates to an aerosol-generating article comprising an aerosol-generating substrate and adapted to generate an inhalable aerosol upon heating. In particular, the present invention relates to an aerosol-generating article comprising a susceptor element thermally coupled to the aerosol-generating substrate and adapted to be inductively heated to provide heat to the aerosol-generating substrate. Aspects of the present disclosure further relate to an aerosol generation system comprising a heating device and an aerosol-generating article of the type described above. [Background technology]

[0002] Aerosol-generating articles in which an aerosol-generating substrate, such as a tobacco-containing substrate, is heated rather than combusted are known in the art.Typically, in such heated smoking articles, 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 the 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] Many prior art documents disclose aerosol generating devices for consuming aerosol-generating articles. Such devices include, for example, electrically heated aerosol generating devices, in which aerosol is generated by heat transfer from one or more electric heater elements of the aerosol generating device to the aerosol-generating substrate of the heated aerosol-generating article. For example, an electrically heated aerosol generating device has been proposed that includes an internal heater blade that is adapted to be inserted into the aerosol-generating substrate. Alternatively, WO2015 / 176898 has proposed an inductively heated aerosol generating article that includes an aerosol-generating substrate and a susceptor disposed within the aerosol-generating substrate.

[0004] Aerosol-generating articles in which the tobacco-containing substrate is heated rather than combusted present a number of challenges not found in conventional smoking articles. First, the tobacco-containing substrate is typically heated to a significantly lower temperature compared to the temperature reached by the combustion front of a conventional cigarette. This can affect the nicotine release from the tobacco-containing substrate and the nicotine delivery to the consumer. At the same time, if the heating temperature is increased in an attempt to enhance nicotine delivery, the aerosol generated typically needs to be cooled more extensively and more quickly before reaching the consumer.

[0005] Second, it typically takes time to heat a tobacco-containing aerosol-generating substrate to one of these temperatures required for aerosol formation, which may delay aerosol delivery to the consumer. When a user first draws on the article, the aerosol that reaches the user may be relatively low in flavor or nicotine content, or both, often referred to as the "cold puff" or "empty puff" effect.

[0006] For example, one such delay may be detectable in aerosol-generating rods and articles in which the aerosol-generating substrate comprises homogenized tobacco material, as the aerosol former and nicotine may not be particularly readily available for release, particularly when using cast leaf homogenized tobacco material prepared from a slurry containing the aerosol former, as opposed to one in which the aerosol former is applied (e.g., sprayed) onto a formed sheet.

[0007] However, it would be desirable to provide new and improved aerosol-generating rods or articles in which the tobacco-containing substrate is heated rather than combusted and which are adapted to address at least one of the challenges faced with aerosol-generating articles that are not typically associated with conventional smoking articles. Summary of the Invention

[0008] The present disclosure relates to an aerosol-generating article for generating an inhalable aerosol upon heating. [Brief description of the drawings]

[0009] [Figure 1] 2 is a schematic diagram of details of a susceptor assembly in one embodiment of an aerosol-generating article according to the present invention. FIG. [Diagram 2] 2 is a schematic diagram of details of a susceptor assembly in another embodiment of an aerosol-generating article according to the present invention. FIG. [Diagram 3] 2 is a schematic diagram of details of a susceptor assembly in yet another embodiment of an aerosol-generating article according to the present invention. FIG. [Figure 4] FIG. 2 is a schematic diagram of a detail of a susceptor assembly in a further embodiment of an aerosol-generating article according to the invention, the susceptor assembly comprising a plurality of bead-like spacer elements. [Diagram 5] 2 is a schematic diagram of an alternative spacer element for use in a susceptor assembly of an aerosol-generating article according to the present invention. FIG. [Figure 6] 1 is a schematic cross-sectional side view of an aerosol-generating article according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The aerosol-generating article may comprise a susceptor assembly.

[0011] The susceptor assembly may include at least one strand of susceptor material.

[0012] At least one strand of susceptor material may be twisted so as to be helically disposed about the longitudinal axis of the susceptor assembly.

[0013] The susceptor assembly may include an aerosol generating element.

[0014] The aerosol-generating element may include at least one strand of porous (eg, fibrous) non-tobacco material that carries the aerosol-forming composition.

[0015] The aerosol-forming composition may include at least 35 percent by weight of an aerosol former (eg, glycerin).

[0016] At least one strand of the aerosol-generating element may be twisted with at least one strand of the susceptor material.

[0017] According to the present invention, there is provided an aerosol-generating article for producing an inhalable aerosol when heated, the aerosol-generating article comprising a susceptor assembly comprising at least one strand of susceptor material, the at least one strand of susceptor material twisted so as to be helically disposed about a longitudinal axis of the susceptor assembly. Further, the susceptor assembly comprises at least one aerosol-generating element comprising at least strands of porous non-tobacco material carrying an aerosol-forming composition comprising at least 35 weight percent of an aerosol former. The at least one strand of the aerosol-generating element is twisted with the at least one strand of susceptor material.

[0018] In contrast to existing aerosol-generating articles, the aerosol-generating article according to the present invention comprises a susceptor assembly in which a composition comprising a significant amount of an aerosol former is held in intimate contact with an inductively heatable material of at least one strand of susceptor material.

[0019] This is accomplished by a twisted arrangement of at least one strand of susceptor material and a strand of porous non-tobacco material carrying the aerosol-forming composition of the aerosol-generating element.

[0020] From a functional point of view, in an aerosol-generating article according to the invention, the strands of porous non-tobacco material carrying an aerosol-forming composition can be considered as aerosol-forming strands. For simplicity, in the following description, the strands of porous non-tobacco material carrying an aerosol-forming composition that form part of the aerosol-generating element will often be referred to as aerosol-forming strands or aerosol-generating strands.

[0021] Because the at least one strand of porous non-tobacco material is sandwiched between or surrounded by adjacent tines or coils formed by the at least one strand of susceptor material, the structure of the susceptor assembly of the aerosol-generating article according to the present invention ensures that a significant proportion of the aerosol former is in close proximity to the heat source at all times. Thus, during use, heat generated by induction heating may be rapidly transferred to the aerosol-forming composition, such as by thermal conduction, from the heated strand of susceptor material to the at least one strand of porous non-tobacco material.

[0022] Thus, rapid heating of the strand of porous non-tobacco material may be achieved within the very first moments after inductive heat supply is initiated. Volatilization of the aerosol former carried by at least one strand of porous non-tobacco material may advantageously help to prevent the occurrence of a "cold puff" effect and generally allow for more consistent and better controlled delivery of the aerosol to the consumer during use.

[0023] As will become apparent from the following description, preferred embodiments of the aerosol-generating article according to the present invention can particularly benefit from a particular mutual arrangement of the strand or strands of susceptor material and the strand or strands of the aerosol-generating element (i.e., the aerosol-forming strand or strands), as well as the use of a particular formulation of the aerosol-forming composition, whereby the aerosol former is particularly adapted to be released more quickly than volatile species contained in the natural aerosol-generating substrate.

[0024] By adjusting certain parameters of the number of strands of susceptor material, the number of aerosol-forming strands, or the helical arrangement of the strands about the longitudinal axis of the susceptor assembly, it may be advantageously possible to fine-tune and control the amount of aerosol former that is volatilized and delivered to the consumer, particularly during the first moments of use after inductive heating has begun. For example, by varying the number of strands of susceptor material and the wire helix angle at which the strands of susceptor material lie about the longitudinal axis of the susceptor, it may be possible to vary the amount of exposed surface area of ​​the aerosol-forming strands, as well as the amount of surface area of ​​the strands of susceptor material or at least one aerosol-forming strand in direct contact with the strands.

[0025] In other preferred embodiments, described in more detail below, the distance between adjacent strands of susceptor material and their spatial arrangement relative to one another can be fine-tuned and controlled. For example, this may be accomplished by providing one or more spacer elements as additional components of the susceptor assembly. Thus, the size of the gap formed within the structure of the susceptor assembly can be adjusted so that the gap is adapted to host a finite amount of aerosol-generating substrates. This can advantageously provide an additional degree of control over the overall amount and spatial distribution of substrates capable of releasing volatile species upon heating provided in the vicinity of the susceptor material.

[0026] As briefly described above, the present invention provides an aerosol-generating article for generating an inhalable aerosol upon heating.

[0027] As used herein, the term "aerosol-generating article" refers to an article that heats an aerosol-generating substrate to generate an inhalable aerosol for delivery to a consumer. As used herein, the term "aerosol-generating substrate" refers to a substrate that has the ability to generate an aerosol by releasing a volatile compound upon heating.

[0028] In an aerosol-generating article according to the invention, the aerosol-forming composition carried by the strands of porous non-tobacco material forming part of the susceptor assembly acts as one such aerosol-generating substrate. In some embodiments, as described in more detail below, the aerosol-generating article may include additional aerosol-generating substrates other than the aerosol-forming composition.

[0029] A conventional cigarette is ignited when a user applies a flame to one end of the cigarette and draws air through the other end. The localized heat provided by the flame and the oxygen in the air drawn through the cigarette causes the end of the cigarette to ignite, and the resulting combustion produces inhalable smoke. In contrast, in heated aerosol-generating articles, the aerosol is generated by heating a flavor-generating substrate, such as tobacco, without the combustion of the flavor-generating substrate. Known heated aerosol-generating articles include, for example, electrically heated aerosol-generating articles and aerosol-generating articles in which the aerosol is generated by the transfer of heat from a combustible fuel element or heat source to a physically separated aerosol-forming material.

[0030] The aerosol generating article according to the invention has particular application in an aerosol generating system comprising an aerosol generating device having an inductor for generating an alternating or fluctuating electromagnetic field. The aerosol generating article interfaces with the aerosol generating device such that the fluctuating electromagnetic field generated by the inductor induces a current in the susceptor assembly causing the strands of susceptor material to heat up. The electrically operated aerosol generating device is preferably capable of generating a fluctuating electromagnetic field having a magnetic field strength (H field strength) of 1 to 5 kiloamperes per meter (kA / m), preferably 2 to 3 kA / m, for example about 2.5 kA / m. The electrically operated aerosol generating device is preferably capable of generating a fluctuating electromagnetic field having a frequency of 1 to 30 MHz, for example 1 to 10 MHz, for example 5 to 7 MHz.

[0031] The aerosol-generating article may be in the shape of a rod. As used herein in connection with the present invention, the term "rod" is used to denote a generally cylindrical element of substantially circular, oval or elliptical cross section.

[0032] The term "longitudinal" as used herein refers to a direction corresponding to a major longitudinal axis of the aerosol-generating article extending between the upstream and downstream ends of the aerosol-generating article. The terms "upstream" and "downstream" as used herein describe the relative positions of an element (or part of an element) of the aerosol-generating article with respect to the direction in which aerosol is transported through the aerosol-generating article during use.

[0033] During use, air is drawn longitudinally through the aerosol-generating article. The term "transverse" refers to a direction perpendicular to the longitudinal axis. Any reference to a "cross section" of an aerosol-generating article or a component of an aerosol-generating article refers to a transverse cross section, unless otherwise specified.

[0034] The term "length" refers to the dimension of a component of an aerosol-generating article in its longitudinal direction. For example, it may be used to refer to the dimension of a rod or elongated tubular element in its longitudinal direction.

[0035] The term "aerosol former" is used herein to describe compounds that, upon volatilization, can assist in the delivery of other vaporized compounds released from the aerosol-generating substrate upon heating, such as nicotine and flavorants in the aerosol. Aerosol formers suitable for inclusion in the aerosol-forming composition 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 glycerol mono-, di-, or triacetate), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate and tetradecanedioate).

[0036] The term "twisted" is used herein to describe a strand of susceptor material that is repeatedly rotated or wound around the longitudinal axis of the susceptor assembly. More specifically, in the context of the present invention, the term "twisted" is used to describe an arrangement in which the strand of susceptor material is helically disposed around the longitudinal axis of the susceptor assembly.

[0037] The phrase "twisted together with at least one strand of susceptor material" is used to describe an aerosol-generating strand that rotates repeatedly about the longitudinal axis of the susceptor assembly and about a single strand of susceptor material or about two or more strands of susceptor material such that the aerosol-generating strand is effectively sandwiched between and thereby held in place by two or more strands of susceptor material.

[0038] Figures 1 and 2 show diagrammatically two such configurations of susceptor assemblies for use in an aerosol-generating article according to the invention. In Figure 1, a single aerosol-generating strand is twisted together with two strands of susceptor material. For simplicity, only the path of the aerosol-generating strand is illustrated by a dotted line. In Figure 2, a single aerosol-generating strand is twisted together with three strands of susceptor material. The dotted lines illustrate the path of a portion of the aerosol-generating strand that is sandwiched between adjacent strands of susceptor material.

[0039] These types of arrangements involving two or more strands are similar to wire rope arrangements. Wire ropes are formed from several strands of metal wire twisted into a helical shape to form a composite rope, in a pattern known as a laid rope. Larger diameter wire ropes consist of multiple strands of such laid rope, in a pattern known as a cable laid.

[0040] As such, certain geometric parameters of the susceptor assemblies of the aerosol-generating articles according to the present invention are identified and described herein with similar nomenclature.

[0041] As an example, the term "strand helix axis" may be used to describe the centroid axis around which the strands are helically wound to form the susceptor assembly. In the case of the susceptor assembly of the present invention, it corresponds to the longitudinal axis of the susceptor assembly. The positive direction of the axis is defined as the direction in which the helix advances. As an example, the strand helix axis may be parallel or coaxial with the longitudinal axis of the aerosol-generating article.

[0042] The strand helix (α w The term θ tangent to the point θ describes the angle between the tangent vector at that point, oriented in the direction of advance of the wire helix, and a plane that is perpendicular to the wire helix axis and passes through that point.

[0043] As briefly described above, in an aerosol-generating article according to the present invention, a susceptor assembly is provided that includes at least one strand of susceptor material and an aerosol-generating element that includes at least one strand of porous non-tobacco material carrying an aerosol-forming composition that includes at least 35 weight percent of an aerosol former.

[0044] At least one strand of susceptor material is twisted so as to be helically disposed about the longitudinal axis of the susceptor assembly, and at least one aerosol-generating strand is twisted with the at least one strand of susceptor material.

[0045] In a preferred embodiment, the at least one or more strands of susceptor material include two or more strands of susceptor material twisted with each other such that the two or more strands of susceptor material are arranged helically around the longitudinal axis of the susceptor assembly, and the at least one aerosol-generating strand is twisted with the two or more strands of susceptor material. Such an embodiment has the advantage that the at least one aerosol-generating strand can be held in place more firmly since a portion of the at least one aerosol-generating strand is disposed between adjacent portions of the two or more strands of susceptor material. Thus, the efficiency of heat transfer from the strands of susceptor material to the aerosol-generating strands can be maximized. Thus, the release of volatilized aerosol former can be rapidly initiated during the very first moment of use of the aerosol-generating article. This can be very effective in combating the cold puff effect.

[0046] In some of the embodiments in which at least one aerosol-generating strand is combined with two or more strands of susceptor material, the at least one aerosol-generating strand is also helically arranged around the longitudinal axis of the susceptor assembly and held in place by being sandwiched between at least two of the two or more strands of susceptor material. This type of arrangement is shown in the drawings in Figures 1 and 2. By adjusting the aerosol-generating strands and the number of strands of susceptor material in the susceptor assembly, it may be possible to vary the percentage of the surface area of ​​the aerosol-generating strand or strands that is exposed to the aerosol-generating strand or strands relative to the percentage of the surface area of ​​the aerosol-generating strand or strands that is in direct contact with one or more of the strands of susceptor material. This may provide a way to fine-tune the amount of heat that is rapidly transferred to the aerosol-generating strand or strands during use, as well as a way that volatilized aerosol formers may be more easily released within the aerosol-generating article.

[0047] In a further embodiment in which at least one aerosol-generating strand is combined with two or more strands of susceptor material, the at least one aerosol-generating strand extends substantially parallel to the longitudinal axis of the susceptor assembly to define a core of the susceptor assembly, and the two or more strands of susceptor material are helically arranged around the at least one aerosol-generating strand. This type of arrangement is illustrated diagrammatically in the drawing of FIG.

[0048] In these embodiments, the aerosol-generating strands may be more effectively protected from damage that may be caused by friction against other surfaces during manufacture of the aerosol-generating article because the strands of susceptor material may substantially surround the aerosol-generating strands, thus reducing the likelihood of the aerosol-generating strands coming into contact with other surfaces during manufacture. Furthermore, depending on the number, size, and angle of the strand helices, the coverage of the aerosol-generating strands or strands in the core of the susceptor assembly over some of the strands of susceptor material may be more or less extensive, which may result in a significantly smaller portion of the surface area of ​​the aerosol-generating strands or strands remaining exposed.

[0049] In an aerosol-generating article according to the invention, at least one strand of susceptor material is a metal strip, filament, pin, or wire.

[0050] The aerosol-forming composition is preferably adsorbed, coated, impregnated or otherwise loaded onto a porous non-tobacco material which preferably acts as an inert carrier, in other words, the porous non-tobacco material is preferably incapable of releasing volatile species into the aerosol formed during use.

[0051] In some embodiments, the porous material is provided in the form of fiber threads, preferably comprising fibers selected from cotton fibers, cellulose fibers, reconstituted natural fibers (including, for example, natural fibers derived from wood pulp), and combinations thereof.

[0052] As briefly described above, the aerosol-forming composition comprises at least 35 percent by weight of aerosol formers. Preferably, the aerosol-forming composition comprises at least 40 percent by weight of aerosol formers. More preferably, the aerosol-forming composition comprises at least 45 percent by weight of aerosol formers. Even more preferably, the aerosol-forming composition comprises at least 50 percent by weight of aerosol formers.

[0053] In particularly preferred embodiments, the aerosol-forming composition comprises at least about 55 percent by weight of the aerosol former, preferably at least about 60 percent by weight of the aerosol former, and more preferably at least about 70 percent by weight of the aerosol former.

[0054] The aerosol-forming composition may comprise up to 95 percent by weight of the aerosol former, preferably no more than 90 percent by weight of the aerosol former, more preferably no more than 85 percent by weight of the aerosol former, and even more preferably no more than 80 percent by weight of the aerosol former.

[0055] In some embodiments, the aerosol forming composition comprises 35 weight percent to about 90 weight percent aerosol formers, preferably 40 weight percent to about 90 weight percent aerosol formers, more preferably 45 weight percent to about 90 weight percent aerosol formers, and even more preferably 50 weight percent to about 90 weight percent aerosol formers. In other embodiments, the aerosol forming composition comprises 35 weight percent to about 85 weight percent aerosol formers, preferably 40 weight percent to about 85 weight percent aerosol formers, more preferably 45 weight percent to about 85 weight percent aerosol formers, and even more preferably 50 weight percent to about 85 weight percent aerosol formers. In further embodiments, the aerosol forming composition comprises 35 weight percent to about 80 weight percent aerosol formers, preferably 40 weight percent to about 80 weight percent aerosol formers, more preferably 45 weight percent to about 80 weight percent aerosol formers, and even more preferably 50 weight percent to about 80 weight percent aerosol formers.

[0056] Preferably, the aerosol former is selected from the group consisting of triethylene glycol, propylene glycol, 1,3-butanediol, glycerin, and mixtures thereof. In a particularly preferred embodiment, the aerosol former is glycerol.

[0057] Further, the aerosol forming composition may include nicotine.

[0058] As used herein in connection with the present invention, the term "nicotine" is used to describe nicotine, nicotine base, or nicotine salts. In embodiments in which the solid aerosol-generating substrate 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.

[0059] The aerosol-forming composition may contain natural nicotine, or synthetic nicotine, or a combination of natural and synthetic nicotine.

[0060] The nicotine content of the aerosol-forming composition may be 0.5 weight percent or more, 1 weight percent or more, 1.5 weight percent or more, or 2 weight percent or more.

[0061] The nicotine content of the aerosol-forming composition may be 10 weight percent or less, 8 weight percent or less, 6 weight percent or less, or 4 weight percent or less.

[0062] The nicotine content of the aerosol-forming composition may be from 0.5 weight percent to 10 weight percent, from 0.5 weight percent to 8 weight percent, from 0.5 weight percent to 6 weight percent, or from 0.5 weight percent to 4 weight percent.

[0063] The nicotine content of the aerosol-forming composition may be from 1 weight percent to 10 weight percent, from 1 weight percent to 8 weight percent, from 1 weight percent to 6 weight percent, or from 1 weight percent to 4 weight percent.

[0064] The nicotine content of the aerosol-forming composition may be from 1.5 weight percent to 10 weight percent, from 1.5 weight percent to 8 weight percent, from 1.5 weight percent to 6 weight percent, or from 1.5 weight percent to 4 weight percent.

[0065] The nicotine content of the aerosol-forming composition may be from 2 weight percent to 10 weight percent, from 2 weight percent to 8 weight percent, from 2 weight percent to 6 weight percent, or from 2 weight percent to 4 weight percent.

[0066] In some embodiments, the aerosol-forming composition may include one or more carboxylic acids.

[0067] The aerosol-forming composition may include a plurality of carboxylic acids. That is, the aerosol-forming composition may include two or more carboxylic acids. For example, the aerosol-forming composition may include two carboxylic acids, three carboxylic acids, four carboxylic acids, or five carboxylic acids.

[0068] The aerosol-forming composition may include one or more carboxylic acids that do not contain non-carboxyl hydroxyl groups.

[0069] As used herein in connection with the present invention, the term "non-carboxyl hydroxyl group" is used to describe a hydroxyl group that does not form part of a carboxyl group.

[0070] The aerosol-forming composition may include one or more carboxylic acids having a pKa in water at 25° C. of 3.5 or less.

[0071] As used herein in connection with the present invention, the term "carboxylic acid having a pKa in water of 3.5 or less at 25° C." is used to describe monobasic carboxylic acids having a pKa in water of 3.5 or less at 25° C. and polybasic carboxylic acids having a pKa in water of 3.5 or less at 25° C.

[0072] The aerosol-forming composition may include multiple carboxylic acids having a pKa in water of 3.5 or less at 25° C. For example, the solid aerosol-generating substrate may include fumaric acid and maleic acid.

[0073] The aerosol-forming composition may include one or more carboxylic acids having a pKa in water at 25° C. of 3.6 or greater.

[0074] As used herein in connection with the present invention, the term "carboxylic acid having a pKa in water of 3.6 or more at 25° C." is used to describe monobasic carboxylic acids having a pKa in water of 3.6 or more at 25° C. and polybasic carboxylic acids having a pKa in water of 3.6 or more at 25° C.

[0075] For example, the aerosol-forming composition may include one or more carboxylic acids selected from acetic acid, benzoic acid, lactic acid, and levulinic acid.

[0076] The aerosol-forming composition may include multiple carboxylic acids having a pKa in water of 3.6 or greater at 25° C. For example, the aerosol-forming composition may include benzoic acid and lactic acid.

[0077] The aerosol-forming composition may include one or more carboxylic acids having a pKa in water at 25°C of 3.5 or less, and one or more carboxylic acids having a pKa in water at 25°C of 3.6 or more.

[0078] For example, the aerosol-forming composition may include one or more carboxylic acids selected from fumaric acid, maleic acid, and malic acid, and one or more carboxylic acids selected from acetic acid, benzoic acid, lactic acid, and levulinic acid.

[0079] For example, the aerosol-forming composition may include fumaric acid and one or more carboxylic acids selected from acetic acid, benzoic acid, lactic acid, and levulinic acid.

[0080] Preferably, the aerosol-forming composition comprises one or more carboxylic acids selected from fumaric acid, maleic acid and malic acid.

[0081] More preferably, the aerosol-forming composition comprises one or more carboxylic acids selected from fumaric acid and maleic acid.

[0082] Most preferably, the aerosol forming composition comprises fumaric acid.

[0083] The aerosol-forming composition may have a total carboxylic acid content of 0.5 weight percent or greater.

[0084] As used herein with respect to the present invention, the term "total carboxylic acid content" is used to describe the combined content of all carboxylic acids in an aerosol-forming composition. For example, if a solid aerosol-generating substrate comprises multiple carboxylic acids consisting of benzoic acid and fumaric acid, the term "total carboxylic acid content" describes the total combined benzoic acid and fumaric acid content of the solid aerosol-generating substrate.

[0085] The aerosol-forming composition may have a total carboxylic acid content of 1 weight percent or greater, 1.5 weight percent or greater, or 2 weight percent or greater.

[0086] The aerosol-forming composition may have a total carboxylic acid content of 8 weight percent or less, 6 weight percent or less, or 4 weight percent or less.

[0087] The aerosol-forming composition may have a total carboxylic acid content of from 0.5 weight percent to 8 weight percent, from 0.5 weight percent to 6 weight percent, or from 0.5 weight percent to 4 weight percent.

[0088] The aerosol-forming composition may have a total carboxylic acid content from 1 weight percent to 8 weight percent, from 1 weight percent to 6 weight percent, or from 1 weight percent to 4 weight percent.

[0089] The aerosol-forming composition may have a total carboxylic acid content of from 1.5 weight percent to 8 weight percent, from 1.5 weight percent to 6 weight percent, or from 1.5 weight percent to 4 weight percent.

[0090] The aerosol-forming composition may have a total carboxylic acid content of from 2 weight percent to 8 weight percent, from 2 weight percent to 6 weight percent, or from 2 weight percent to 4 weight percent.

[0091] The aerosol-forming composition may include one or more cellulosic agents.

[0092] As used herein in connection with the present invention, the term "cellulosic agent" is used to describe a cellulosic material. Examples of cellulosic agents include cellulosic film formers, cellulosic reinforcing agents, and cellulosic binders.

[0093] The aerosol-forming composition may include multiple cellulose-based agents. That is, the solid aerosol-generating substrate may include two or more cellulose-based agents. For example, the aerosol-forming composition may include two cellulose-based agents, three cellulose-based agents, four cellulose-based agents, or five cellulose-based agents.

[0094] The aerosol-forming composition may have a total cellulosic agent content of 25 weight percent or more, or 30 weight percent or more.

[0095] As used herein, the term "total cellulosic agent" is used to describe the total content of all cellulosic agents in a solid aerosol-forming composition. For example, if an aerosol-forming composition includes multiple cellulosic agents consisting of a cellulosic film-forming agent, a cellulosic reinforcing agent, and a cellulosic binder, the term "total cellulosic agent content" describes the combined cellulosic film-forming agent content, cellulosic reinforcing agent content, and cellulosic binder content of the aerosol-forming composition.

[0096] The aerosol-forming composition may have a total cellulosic agent content of 35 weight percent or greater.

[0097] The diameter of the at least one strand of susceptor material may be at least 0.25 millimeters. Preferably, the diameter of the at least one strand of susceptor material is at least 0.3 millimeters. More preferably, the diameter of the at least one strand of susceptor material is at least 0.4 millimeters. Even more preferably, the diameter of the at least one strand of susceptor material is at least 0.5 millimeters.

[0098] The diameter of the at least one strand of susceptor material may be up to 2 millimeters. Preferably, the diameter of the at least one strand of susceptor material is 1.5 millimeters or less. More preferably, the diameter of the at least one strand of susceptor material is 1.25 millimeters or less. Even more preferably, the diameter of the at least one strand of susceptor material is 1 millimeter or less.

[0099] In some embodiments, the diameter of the at least one strand of susceptor material is between 0.3 millimeters and 1.5 millimeters, preferably between 0.3 millimeters and 1.25 millimeters, and more preferably between 0.3 millimeters and 1 millimeter. In other embodiments, the diameter of the at least one strand of susceptor material is between 0.4 millimeters and 1.5 millimeters, preferably between 0.4 millimeters and 1.25 millimeters, and more preferably between 0.4 millimeters and 1 millimeter. In further embodiments, the diameter of the at least one strand of susceptor material is between 0.5 millimeters and 1.5 millimeters, preferably between 0.5 millimeters and 1.25 millimeters, and more preferably between 0.5 millimeters and 1 millimeter.

[0100] The diameter of the at least one aerosol-generating strand may be at least 0.5 millimeters. Preferably, the diameter of the at least one aerosol-generating strand is at least 0.6 millimeters. More preferably, the diameter of the at least one aerosol-generating strand is at least 0.7 millimeters.

[0101] The diameter of the at least one aerosol-generating strand may be up to 2 millimeters. Preferably, the diameter of the at least one aerosol-generating strand is 1.5 millimeters or less. More preferably, the diameter of the at least one aerosol-generating strand is 1.25 millimeters or less. Even more preferably, the diameter of the at least one aerosol-generating strand is 1 millimeter or less.

[0102] In some embodiments, the diameter of the at least one aerosol-generating strand is between 0.5 mm and 1.5 mm, preferably between 0.5 mm and 1.25 mm, more preferably between 0.5 mm and 1 mm. In other embodiments, the diameter of the at least one aerosol-generating strand is between 0.6 mm and 1.5 mm, preferably between 0.6 mm and 1.25 mm, more preferably between 0.6 mm and 1 mm. In other embodiments, the diameter of the at least one aerosol-generating strand is between 0.7 mm and 1.5 mm, preferably between 0.7 mm and 1.25 mm, more preferably between 0.7 mm and 1 mm.

[0103] In certain embodiments, the strand helix angle of the at least one strand of susceptor material is at least 20 degrees. Preferably, the strand helix angle of the at least one strand of susceptor material is at least 30 degrees. More preferably, the strand helix angle of the at least one strand of susceptor material is at least 35 degrees. Even more preferably, the strand helix angle of the at least one strand of susceptor material is at least 40 degrees. In particularly preferred embodiments, the strand helix angle of the at least one strand of susceptor material is at least 45 degrees.

[0104] The strand helix angle of the at least one strand of susceptor material is 80 degrees or less. Preferably, the strand helix angle of the at least one strand of susceptor material is 70 degrees or less. More preferably, the strand helix angle of the at least one strand of susceptor material is 65 degrees or less. Even more preferably, the strand helix angle of the at least one strand of susceptor material is 60 degrees or less. In a particularly preferred embodiment, the strand helix angle of the at least one strand of susceptor material is 55 degrees or less.

[0105] In some embodiments, the strand helix angle of at least one strand of the susceptor material is between 20 degrees and 80 degrees, preferably between 20 degrees and 70 degrees, more preferably between 20 degrees and 65 degrees, even more preferably between 20 degrees and 60 degrees, and most preferably between 20 degrees and 55 degrees.

[0106] In some embodiments, the strand helix angle of at least one strand of susceptor material is between 30 degrees and 80 degrees, preferably between 30 degrees and 70 degrees, more preferably between 30 degrees and 65 degrees, even more preferably between 30 degrees and 60 degrees, and most preferably between 30 degrees and 55 degrees.

[0107] In some embodiments, the strand helix angle of at least one strand of the susceptor material is between 35 degrees and 80 degrees, preferably between 35 degrees and 70 degrees, more preferably between 35 degrees and 65 degrees, even more preferably between 35 degrees and 60 degrees, and most preferably between 35 degrees and 55 degrees.

[0108] In some embodiments, the strand helix angle of at least one strand of susceptor material is between 40 degrees and 80 degrees, preferably between 40 degrees and 70 degrees, more preferably between 40 degrees and 65 degrees, even more preferably between 40 degrees and 60 degrees, and most preferably between 40 degrees and 55 degrees.

[0109] In some embodiments, the strand helix angle of the at least one strand of susceptor material is between 45 degrees and 80 degrees, preferably between 45 degrees and 70 degrees, more preferably between 45 degrees and 65 degrees, even more preferably between 45 degrees and 60 degrees, and most preferably between 45 degrees and 55 degrees. Without wishing to be bound by theory, arranging the at least one strand of susceptor material with a strand helix angle falling within the aforementioned ranges can advantageously provide a susceptor assembly with particularly good structural strength, with the at least one aerosol-generating strand being held in place very stably. Furthermore, arranging the at least one strand of susceptor material with a strand helix angle falling within the aforementioned ranges can advantageously protect the at least one aerosol-generating strand from potential damage caused by friction during manufacturing and handling of the susceptor assembly. At the same time, in one such susceptor assembly, satisfactory heat transfer from the strand or strands of susceptor material to at least one aerosol-generating strand may be combined with particularly effective mass transfer based on aerosol generation and delivery to the consumer. At helix angles in the range of about 20 degrees, there is more material per unit of length, providing the ability to generate more heat. At helix angles in the range of about 80 degrees, there is less material per unit of length, reducing manufacturing costs.

[0110] In some embodiments, the aerosol-generating article comprises an aerosol-generating rod that includes a primary aerosol-generating substrate. A susceptor assembly is thermally coupled to the aerosol-generating substrate. More specifically, this is accomplished by having the susceptor assembly extend longitudinally within the aerosol-generating rod and embedded within the aerosol-generating substrate.

[0111] As an example, the aerosol-generating article may comprise a sheet of homogenized tobacco material assembled to form a rod extending along a longitudinal axis of the aerosol-generating article. The susceptor assembly may be embedded within the assembly of the sheet of homogenized tobacco material. Alternatively, the aerosol-generating article may comprise a rod including cut filler obtained by cutting tobacco leaf material or reconstituted or homogenized tobacco material. The susceptor assembly may be embedded within the cut filler, for example, such that it is surrounded by the cut filler.

[0112] In these embodiments, the rod with the aerosol-generating substrate provides an additional source of aerosol that generally reaches a temperature sufficient to release aerosol species during use slower than the aerosol-forming composition carried by at least one aerosol-generating strand in the susceptor assembly. Thus, by adjusting the content of the aerosol-forming composition in the aerosol-generating article relative to the content of the additional aerosol-generating substrate, as well as by varying the formulation of the aerosol-forming composition, or the nature and composition of the additional aerosol-generating substrate, it may be possible to provide an aerosol-generating article that may be associated with a specially tailored aerosol delivery profile, including a flavor delivery profile. In particular, it may be possible to fine-tune the release of the aerosol from the susceptor assembly to counter possible cold puff effects associated with the additional aerosol-generating substrate. For example, the release of the aerosol from the susceptor assembly may be fine-tuned depending on one or more of the nature and composition of the additional aerosol-generating substrate, the geometry of the rod containing the additional aerosol-generating substrate, the heating profile over time, etc.

[0113] In certain embodiments, the susceptor assembly further comprises one or more spacer elements of a non-conductive material, the one or more spacer elements configured to create a gap between two adjacent strands of the two or more susceptor materials such that respective portions of two adjacent strands of the two or more susceptor materials are at a predetermined distance from each other.

[0114] The aerosol-generating article may comprise a secondary aerosol-generating substrate provided in at least one of the predetermined gaps.

[0115] This may advantageously allow for more efficient use of the volume occupied by the susceptor assembly within the aerosol-generating article, as a greater proportion of such volume may be occupied by active substances contributing to the overall aerosol generation. Furthermore, by selecting a secondary aerosol-generating substrate adapted to release volatile species at a different temperature compared to the aerosol-generating strands and the aerosol formers contained therein, it may be possible to further widen the range of flavour release profiles that may be provided to the consumer. For example, the secondary aerosol-generating substrate may be adapted to release volatile species with some delay compared to the aerosol-generating strands and the aerosol formers contained therein.

[0116] In embodiments in which the susceptor assembly is thermally coupled to the primary aerosol-generating substrate, the secondary aerosol-generating substrate may be adapted to emit volatile species, for example, before or substantially simultaneously with the primary aerosol-generating substrate, allowing for very fine tuning of aerosol emission and delivery to the consumer, and many different combinations and flavors and delivery profiles can be devised by controlling the times and amounts of different aerosol species emitted from the various sources contained in the aerosol-generating article.

[0117] In some of these embodiments, the one or more spacer elements include a bead provided on one of the two or more strands of susceptor material.

[0118] The beads may provide spacer elements that are easy to assemble with two or more strands of susceptor material during manufacture of the susceptor assembly. For example, the beads may be provided as droplets of heat-resistant adhesive deposited on the strands of susceptor material. One such bead may have the advantage of a substantially smooth outer surface, which is desirable because it is less likely to damage the aerosol-generating strand when it is assembled with the bead-bearing strand of susceptor material.

[0119] Preferably, the equivalent diameter of the beads is at least 1.5 times the diameter of the strands of susceptor material, and more preferably, the equivalent diameter of the beads is at least twice the diameter of the strands of susceptor material.

[0120] In preferred embodiments, the equivalent diameter of the beads may be at least about 0.75 millimeters, preferably at least about 1 millimeter, more preferably at least about 1.25 millimeters, and even more preferably at least about 1.5 millimeters.

[0121] In some embodiments, the equivalent diameter of the beads may be 3 millimeters or less, preferably 2.5 millimeters or less, and more preferably 2 millimeters or less.

[0122] For beads having an equivalent diameter falling within the ranges mentioned above, the gaps created between adjacent strands may be easy to fill with additional aerosol-generating substrate.

[0123] In a preferred embodiment, the one or more spacer elements comprise a plurality of beads, the beads being evenly spaced along the length of one of the two or more strands of susceptor material.

[0124] These evenly distributed beads force the strands through the gaps in a regular manner, so that the gaps are provided with a predetermined pattern along the length of the strand, and the gaps are adapted to receive an aerosol-generating substrate, e.g., in the form of a gel.

[0125] In other of these embodiments, the one or more spacer elements comprise a plate including one or more openings, the plate being disposed transversely to the longitudinal axis of the susceptor assembly, each of the one or more openings being adapted to receive a corresponding one of the two or more strands of susceptor material.

[0126] Using one such plate as a spacer element can have the advantage that by controlling the size and mutual arrangement of the openings extending through the plate, one can have greater control over how different strands within the susceptor assembly are positioned relative to each other.

[0127] Preferably, the plate is circular and the one or more openings are evenly spaced about the longitudinal axis.

[0128] The use of a substantially circular plate may be advantageous in that it is highly compatible with the pseudo-cylindrical shape of the susceptor assembly and, more importantly, with the rod-shaped aerosol-generating article that contains the susceptor assembly. By having openings evenly spaced about the longitudinal axis of the plate, advantageously, the arrangement of the strands within the susceptor assembly relative to the longitudinal axis of the susceptor assembly may be better controlled. This may help ensure more uniform heat generation during use, as well as more uniform heat transfer and aerosol generation and delivery during use.

[0129] The plate may include a central opening extending therethrough coaxially with the longitudinal axis.

[0130] Providing a spacer plate with a central opening may be particularly desirable when such a central opening is used to receive an aerosol-generating strand, particularly in embodiments where the aerosol-generating strand extends to the core of the susceptor assembly, in which case the central opening of the spacer plate may be used to stably hold the aerosol-generating strand in a core position along the longitudinal axis of the susceptor assembly.

[0131] In one embodiment, an aerosol-generating article for generating an inhalable aerosol upon heating according to the present invention may comprise a susceptor assembly, the susceptor assembly comprising at least one strand of susceptor material, the at least one strand of susceptor material twisted to be helically disposed about a longitudinal axis of the susceptor assembly, and an aerosol-generating element comprising at least one aerosol-forming strand. The susceptor assembly further comprises one or more spacer elements of a non-conductive material, the one or more spacer elements configured to create a gap between the at least one strand of susceptor material and two adjacent ones of the at least one aerosol-forming strand of the aerosol-generating element, such that the at least one strand of susceptor material and each adjacent two ones of the at least one aerosol-forming strand of the aerosol-generating element are configured to be at a predetermined distance from each other. The aerosol-generating article according to the present invention may comprise a downstream section at a location downstream of the susceptor assembly. For example, in an embodiment in which the aerosol-generating article comprises a rod including an aerosol-generating substrate to which the susceptor assembly is thermally coupled by being embedded within the aerosol-generating substrate, the downstream section may be at a position downstream of the rod.

[0132] The downstream section may include one or more downstream elements.

[0133] The downstream section may include a hollow section between the mouth end of the aerosol-generating article and the susceptor assembly. The hollow section may comprise a hollow tubular element.

[0134] As used herein, terms such as "hollow tubular segment" and "hollow tubular element" are used to refer to a generally elongated element that defines a lumen or airflow passage along its longitudinal axis. In particular, the term "tubular" is used in reference to an element or segment that has a substantially cylindrical cross-section and defines at least one airflow conduit that establishes uninterrupted fluid communication between an upstream end of the tubular element or segment and a downstream end of the tubular element or segment. However, it will be appreciated that alternative shapes (e.g., alternative cross-sectional shapes) of the tubular element or segment may be possible.

[0135] In the context of the present invention, a hollow tubular segment or a hollow tubular element provides an unrestricted flow path, which means that the hollow tubular segment or the hollow tubular element provides a negligible level of resistance to withdrawal (RTD).

[0136] The resistance to draw (RTD) of an aerosol-generating article or component thereof, such as a segment of filtration material, may be evaluated as the negative pressure that must be applied to the downstream end of the article or component to maintain a steady volumetric flow rate of 17.5 ml / sec of air through the article or component. Those skilled in the art can find further details on measurement methods, test conditions, etc. in ISO 6565:2015(2015).

[0137] The downstream section may comprise a support element located downstream of the susceptor assembly. For example, the support element may be provided immediately downstream of the susceptor assembly, preferably in an arrangement in abutment with the susceptor assembly or with a segment, such as a rod, of the aerosol-generating substrate on which the susceptor assembly may be provided. The support element may be in the form of, for example, a plug of cellulose acetate. The support element itself may be hollow.

[0138] The downstream section may comprise an aerosol cooling element positioned downstream of the susceptor assembly. The aerosol cooling element may be provided immediately downstream of the susceptor assembly or immediately downstream of a segment, such as a rod, of the aerosol-generating substrate on which the susceptor assembly may be provided. Alternatively, another element may be provided between the susceptor assembly or segment comprising the susceptor assembly and the aerosol cooling element. For example, the support element described above may be positioned between the susceptor assembly or segment comprising the susceptor assembly and the aerosol cooling element. In such a case, all three elements may be disposed in abutting relationship along the longitudinal axis of the aerosol-generating article.

[0139] In certain embodiments, the aerosol cooling element may be provided in the form of a hollow tubular element with a ventilation zone disposed at a position along the hollow tubular element and configured to allow ingress of air from the external environment when a consumer inhales the aerosol-generating article.

[0140] The downstream section may include a mouthpiece element. The mouthpiece element may be located at the downstream end of the aerosol-generating article, and thus may be located downstream of the susceptor assembly, or downstream of a segment that includes a susceptor assembly, as well as downstream of any other one of the optional elements mentioned above. The mouthpiece element extends all the way to the mouth end of the aerosol-generating article.

[0141] The mouthpiece element preferably comprises at least one mouthpiece filter segment of a fibrous filtration material. Suitable fibrous filtration materials will be known to those skilled in the art. Particularly preferably, the at least one mouthpiece filter segment comprises a cellulose acetate filter segment formed from cellulose acetate tow.

[0142] In certain embodiments of the invention, the downstream section may comprise an oral end recess at a downstream end downstream of the mouthpiece filter segment as described above. The oral end cavity may be defined by a hollow tubular element provided at the downstream end of the mouthpiece. The oral end cavity may be defined by an outer wrapper of the mouthpiece element, the outer wrapper extending in a downstream direction from the mouthpiece element.

[0143] The mouthpiece element may optionally include a flavorant, which may be provided in any suitable form, for example, the mouthpiece element may include one or more capsules, beads or granules of flavorant, or one or more flavor-loaded threads or filaments.

[0144] Preferably, the mouthpiece element has a low particle filtration efficiency.

[0145] Preferably, the mouthpiece is formed from a segment of fibrous filtration material.

[0146] The mouthpiece element is preferably surrounded by a plug wrap.

[0147] An aerosol-generating article according to the invention may comprise an upstream section at a location upstream of the susceptor assembly. For example, in embodiments in which the aerosol-generating article comprises a rod including an aerosol-generating substrate to which the susceptor assembly is thermally coupled, such as by being embedded within the aerosol-generating substrate, the upstream section may be located upstream of the rod.

[0148] The upstream section may comprise one or more upstream elements, hi some embodiments, the upstream section may comprise an upstream element disposed immediately upstream of a susceptor assembly or immediately upstream of a segment that comprises a susceptor assembly.

[0149] The upstream element may provide an improved appearance to the upstream end of the aerosol-generating article. Additionally, if desired, the upstream element may be used to provide information about the aerosol-generating article, such as information about the brand, flavor, content, or details of the aerosol-generating device with which the article is intended to be used.

[0150] The upstream element may be a porous plug element, such as a plug of cellulose acetate tow.

[0151] As briefly described above, an aerosol generating system according to the present invention comprises a heating device and an aerosol generating article in accordance with the above description.

[0152] The present invention therefore also relates to an aerosol generating system comprising a heating device, for example an electrically heated aerosol generating device, and an aerosol generating article including a susceptor assembly as described above.

[0153] Examples of suitable aerosol generating devices are known to those skilled in the art. In general, a suitable aerosol generating device comprises a cavity (i.e., a heating chamber) for receiving an aerosol-generating article, and one or more inductor elements adapted to generate a fluctuating electromagnetic field in the cavity. In addition, a suitable aerosol generating device typically comprises a power supply connected to the one or more inductor elements, and a control element configured to control the supply of power from the power supply to the one or more inductor elements.

[0154] Each inductor element may comprise one or more coils that generate a varying electromagnetic field. The coil(s) may surround the cavity.

[0155] The aerosol generating device is preferably capable of generating an alternating electromagnetic field of 1 to 30 MHz, for example, an alternating electromagnetic field of 2 to 10 MHz, for example, 5 to 7 MHz.

[0156] The device is preferably capable of generating a fluctuating electromagnetic field having a magnetic field strength (H field) of 1-5 kA / m, for example a magnetic field strength of 2-3 kA / m, for example about 2.5 kA / m.

[0157] The aerosol generating device is preferably a portable or handheld aerosol generating device that a user can comfortably hold between the fingers of one hand.

[0158] The aerosol generating device may be substantially cylindrical in shape.

[0159] The aerosol generating device may have a length of about 70 millimeters to about 120 millimeters.

[0160] The power source may be any suitable power source, for example a direct current voltage source such as a battery. In one embodiment, the power source is a lithium ion battery. Alternatively, the power source may be a nickel metal hydride battery, a nickel cadmium battery, or a lithium-based battery (e.g., a lithium cobalt battery, a lithium iron phosphate battery, a lithium titanate battery, or a lithium polymer battery).

[0161] The control element may be a simple switch, or alternatively, the control element may be an electronic circuit and may include one or more microprocessors or microcontrollers.

[0162] Features described with respect to one or more of the embodiments may equally be applied to the other embodiments of the invention, in particular features described in relation to an aerosol generating article may equally be applied to an aerosol generating system.

[0163] The present invention is defined in the claims. However, below is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of any other examples, embodiments, or aspects described herein.

[0164] Example 1: An aerosol-generating article for generating an inhalable aerosol upon heating, said aerosol-generating article comprising:

[0165] 1. An aerosol-generating article comprising: a susceptor assembly comprising: at least one strand of susceptor material, the at least one strand of susceptor material twisted such that the at least one strand of susceptor material is helically disposed about a longitudinal axis of the susceptor assembly; and at least one aerosol-generating strand, the at least one aerosol-generating strand twisted with the at least one strand of susceptor material.

[0166] Example 2: An aerosol-generating article as described in Example 1, wherein at least one aerosol-generating strand comprises a strand of porous non-tobacco material carrying an aerosol-forming composition.

[0167] Example 3: The aerosol-generating article of Example 2, wherein the aerosol-forming composition comprises at least 35 weight percent of the aerosol former.

[0168] Example 4: The aerosol-generating article of Example 2, wherein the aerosol-forming composition comprises at least 40 weight percent of the aerosol former.

[0169] Example 5: The aerosol-generating article of Example 2, wherein the aerosol-forming composition comprises at least 45 weight percent of the aerosol former.

[0170] Example 6: The aerosol-generating article of Example 2, wherein the aerosol-forming composition comprises at least 50 weight percent of the aerosol former.

[0171] Example 7: The heated aerosol-generating article according to any one of Examples 3 to 6, wherein the aerosol former is selected from the group consisting of triethylene glycol, propylene glycol, 1,3-butanediol, glycerol, glycerol monoacetate, glycerol diacetate, glycerol triacetate, dimethyl dodecanedioate, and dimethyl tetradecanedioate.

[0172] Example 8: An aerosol-generating article according to any one of the preceding examples, wherein at least one or more strands of susceptor material include two or more strands of susceptor material twisted together such that the two or more strands of susceptor material are helically arranged around the longitudinal axis of the susceptor assembly and the at least one aerosol-generating strand is twisted with the two or more strands of susceptor material.

[0173] Example 9: An aerosol-generating article as described in Example 8, wherein at least one aerosol-generating strand is also helically arranged around the longitudinal axis of the susceptor assembly and held in place by being sandwiched between at least two of the two or more strands of susceptor material.

[0174] Example 10: An aerosol-generating article as described in Example 8, wherein at least one aerosol-generating strand extends substantially parallel to a longitudinal axis of the susceptor assembly to define a core of the susceptor assembly, and two or more strands of susceptor material are spirally arranged around the at least one aerosol-generating strand.

[0175] Example 11: An aerosol-generating article according to any one of the preceding examples, wherein at least one strand of susceptor material is a metal strip, filament, pin, or wire.

[0176] Example 12: An aerosol-generating article according to any one of the preceding examples, wherein the aerosol-forming composition is adsorbed, coated, impregnated, or otherwise loaded onto the porous material.

[0177] Example 13: An aerosol-generating article according to any one of the preceding examples, wherein the porous material is formed from a fibrous material.

[0178] Example 14: An aerosol-generating article according to any one of the preceding examples, wherein the porous material is provided in the form of a fibrous thread.

[0179] Example 15: The aerosol-generating article of Example 14, wherein the fiber yarn comprises fibers selected from cotton fibers, cellulose fibers, reconstituted natural fibers, and combinations thereof.

[0180] Example 16: An aerosol-generating article according to any one of the preceding examples, wherein at least one aerosol-generating strand has a diameter of at least 0.5 millimeters.

[0181] Example 17: An aerosol-generating article according to any one of the preceding examples, wherein at least one aerosol-generating strand has a diameter of 1.5 millimeters or less.

[0182] Example 18: An aerosol-generating article according to any one of the preceding examples, wherein at least one strand of susceptor material has a diameter of at least 0.3 millimeters.

[0183] Example 19: An aerosol-generating article according to any one of the preceding examples, wherein at least one strand of susceptor material has a diameter of 1.5 millimeters or less.

[0184] Example 20: An aerosol-generating article according to any one of the preceding examples, wherein at least one strand of susceptor material has a strand helix angle of less than 80 degrees.

[0185] Example 21: An aerosol-generating article according to any one of the preceding examples, wherein the aerosol-generating article comprises an aerosol-generating rod including an aerosol-generating substrate, and the susceptor assembly is thermally coupled to the first aerosol-generating substrate.

[0186] Example 22: An aerosol-generating article as described in Example 21, wherein the susceptor assembly extends longitudinally within the aerosol-generating rod and is embedded within the aerosol-generating substrate.

[0187] Example 23: An aerosol-generating article described in any one of Examples 8 to 22, wherein the susceptor assembly further comprises one or more spacer elements of a non-conductive material, the one or more spacer elements being configured to create a gap between two adjacent strands of the two or more susceptor materials, such that respective portions of the two adjacent strands of the two or more susceptor materials are at a predetermined distance from each other.

[0188] Example 24: An aerosol-generating article as described in Example 23, comprising a secondary aerosol-generating substrate provided in at least one of the pre-defined gaps.

[0189] Example 25: The aerosol-generating article of Example 23, wherein the one or more spacer elements include a bead provided on one of the two or more strands of susceptor material.

[0190] Example 26: An aerosol-generating article as described in Example 25, wherein the equivalent diameter of the beads is at least 0.75 millimeters.

[0191] Example 27: An aerosol-generating article as described in Example 26, wherein one or more spacer elements comprise a plurality of beads, the beads being evenly spaced along the length of one of the two or more strands of susceptor material.

[0192] Example 28: An aerosol-generating article described in any one of Examples 23 to 27, wherein one or more spacer elements include a plurality of beads, the beads being evenly spaced along the length of one of the two or more strands of susceptor material.

[0193] Example 28: An aerosol-generating article described in Example 23 or Example 24, wherein one or more spacer elements include a plate including one or more openings, the plate being arranged transversely to the longitudinal axis of the susceptor assembly, and each of the one or more openings being adapted to receive a corresponding one of the two or more strands of susceptor material.

[0194] Example 29: An aerosol-generating article as described in Example 28, wherein the plate is circular and the one or more openings are evenly spaced around the longitudinal axis.

[0195] Example 30: An aerosol-generating article as described in example 28 or 29, wherein the plate has a central opening extending through the plate coaxially with the longitudinal axis.

[0196] Example 31: An aerosol-generating article described in one of Examples 28 to 30, wherein one or more spacer elements comprise a plurality of plates evenly spaced along the length of the susceptor assembly, each plate comprising one or more openings.

[0197] Example 32: An aerosol-generating article for generating an inhalable aerosol upon heating, the aerosol-generating article comprising:

[0198] an aerosol-generating rod including a first aerosol-generating substrate;

[0199] a susceptor assembly thermally coupled to the first aerosol-generating substrate;

[0200] The susceptor assembly comprises:

[0201] two or more strands of susceptor material twisted together such that the two or more strands of susceptor material are helically disposed about a longitudinal axis of the susceptor assembly;

[0202] one or more spacer elements of a non-conductive material configured to create a gap between two adjacent ones of the two or more strands of susceptor material such that respective portions of the two or more adjacent ones of the strands of susceptor material are at a predetermined distance from each other;

[0203] a second aerosol-generating substrate provided in at least one of the predetermined gaps.

[0204] Example 33: An aerosol generating system comprising a heating device and the aerosol-generating article according to any one of Examples 1 to 32.

[0205] Example 34. An aerosol-generating article for generating an inhalable aerosol upon heating, the aerosol-generating article comprising a susceptor assembly, the susceptor assembly comprising at least one strand of susceptor material, the at least one strand of susceptor material being twisted such that it is helically disposed about a longitudinal axis of the susceptor assembly, and an aerosol-generating element comprising the at least one strand, the at least one strand of susceptor material being twisted such that it is helically disposed about a longitudinal axis of the susceptor assembly, the susceptor assembly further comprising one or more spacer elements of a non-conductive material, the one or more spacer elements being configured to create a gap between the at least one strand of susceptor material and two adjacent ones of the at least one strand of the aerosol-generating element, the at least one strand of the susceptor material being configured such that each adjacent two of the at least one strand of susceptor material and the at least one strand of the aerosol-generating element are at a predetermined distance from each other.

[0206] A detail of a susceptor assembly 100 for use in an aerosol-generating article according to the present invention is shown in FIG. 1. The susceptor assembly 100 comprises a strand 102 of susceptor material twisted to be helically disposed about the longitudinal axis of the susceptor assembly 100. In addition, the susceptor assembly 100 comprises one aerosol-generating strand 104, which is provided in the form of a cotton thread and carries an aerosol-forming composition comprising at least 35 weight percent of an aerosol former. The aerosol-generating strand 104 is twisted with the strand 102 of susceptor material. As shown in FIG. 1, the susceptor assembly 100 also comprises a further strand 106 of susceptor material, which is also helically disposed about the longitudinal axis of the susceptor assembly and twisted with the strand 102 of susceptor material and the aerosol-generating strand 104. As shown, portions of the aerosol-generating strand 104 are sandwiched between respective portions of the strands of susceptor material 102, 106, and are therefore held in place within the susceptor assembly. At the same time, this ensures intimate contact between the susceptor material and the cotton yarn loaded with the aerosol-forming composition, which facilitates heat transfer towards the aerosol former carried by the cotton yarn during use.

[0207] Another embodiment of a susceptor assembly 200 for use in an aerosol-generating article according to the present invention is shown in Figure 2. The general structure of the susceptor assembly 200 of Figure 2 is similar to the general structure of the susceptor assembly 100 of Figure 1. However, the susceptor assembly 200 comprises three strands 202, 206, and 208 of susceptor material twisted together with one aerosol-generating strand 204. The dashed lines in Figure 2 indicate a portion of the aerosol-generating strand 204 sandwiched between respective portions of the strands of susceptor material 202, 206, and 208. This arrangement may provide increased stability to the aerosol-generating strand within the susceptor assembly.

[0208] A further embodiment of a susceptor assembly 300 for use in an aerosol-generating article according to the present invention is shown in Figure 3. The susceptor assembly 300 of Figure 3 comprises an aerosol-generating strand 304 that defines a core of the susceptor assembly and extends along a longitudinal axis of the susceptor assembly. In addition, the susceptor assembly 300 comprises five strands 302, 306, 308, 310, and 312 of susceptor material twisted in a helical arrangement around the aerosol-generating strand. Thus, the aerosol-generating strand 304 in the core is particularly protected from friction against other surfaces during manufacture of the aerosol-generating article, since it is substantially enveloped by the strands of susceptor material.

[0209] FIG. 4 illustrates yet another embodiment of a susceptor assembly 400 for use in an aerosol-generating article according to the present invention. Similar to the susceptor assembly 100 of FIG. 1, the susceptor assembly 400 of FIG. 4 comprises two strands 402 and 406 of susceptor material twisted together with one aerosol-generating strand 404. The dashed lines in FIG. 4 indicate a portion of the aerosol-generating strand 404 sandwiched between respective portions of the strands 402 and 406 of susceptor material. Spacer elements in the form of beads 408 are disposed substantially evenly spaced along the strands 402 of susceptor material and adapted to maintain certain portions of the strands 402 and 406 of susceptor material at a predetermined distance from one another. Thus, a gap 10 is defined between such portions of the strands 402 and 406 of susceptor material, which may host additional aerosol-generating substrates.

[0210] FIG. 5 illustrates alternative forms in which spacer elements may be provided for inclusion in a susceptor element of the type illustrated in FIG. 4. All three spacer elements 508, 608, and 708 illustrated in FIG. 4 are in the form of plate elements with one or more openings extending therethrough. Plate element 508 includes a single opening 512 located substantially at the center of plate element 508. Plate element 608 includes two openings 612 evenly spaced about the longitudinal axis of the plate element. Plate element 708 includes both a plurality of openings 712 disposed substantially evenly spaced about the longitudinal axis of the plate element, and a central opening 714. The openings of each plate element may receive one or more of the respective strands forming the susceptor assembly such that they are kept at a predetermined distance from one another, or more generally to control the overall shape and volume of the susceptor assembly.

[0211] FIG. 6 shows an example of an aerosol-generating article 10 according to the present invention.

[0212] The aerosol-generating article 10 shown in Figure 6 comprises a rod 12 of aerosol-generating substrate 12 and a downstream section 14 located downstream of the rod 12 of aerosol-generating substrate. In addition, the aerosol-generating article 10 comprises an upstream section 16 located upstream of the rod 12 of aerosol-generating substrate. Thus, the aerosol-generating article 10 may extend from an upstream or distal end 18 to a downstream or oral end 20.

[0213] The aerosol-generating article has a total length of about 45 millimeters.

[0214] The downstream section 14 comprises a support element 22 located immediately downstream of the rod 12 of the aerosol-generating substrate, the support element 22 being longitudinally aligned with the rod 12. In the embodiment of Figure 1, the upstream end of the support element 18 abuts the downstream end of the rod 12 of the aerosol-generating substrate. The downstream section 14 further comprises an aerosol cooling element 24 located immediately downstream of the support element 22, the aerosol cooling element 24 being longitudinally aligned with the rod 12 and the support element 22. In the embodiment of Figure 1, the upstream end of the aerosol cooling element 24 abuts the downstream end of the support element 22.

[0215] The support element 22 and the aerosol cooling element 24 together define an intermediate hollow section 50 of the aerosol-generating article 10. As a whole, the intermediate hollow section 50 does not contribute substantially to the overall RTD of the aerosol-generating article. The RTD of the intermediate hollow section 26 as a whole is substantially 0 millimeters HO.

[0216] The support element 22 may include a first hollow tubular segment 26. The first hollow tubular segment 26 is provided in the form of a hollow cylindrical tube made from cellulose acetate. The first hollow tubular segment 26 defines an interior cavity 28 extending entirely from an upstream end 30 of the first hollow tubular segment to a downstream end 32 of the first hollow tubular segment 20. The interior cavity 28 is substantially empty, thus allowing substantially unrestricted airflow along the interior cavity 28. The first hollow tubular segment 26, and consequently the support element 22, does not substantially contribute to the overall RTD of the aerosol-generating article 10. More specifically, the RTD of the first hollow tubular segment 26 (which is substantially the RTD of the support element 22) is substantially 0 millimeters H2O.

[0217] The first hollow tubular segment 26 has a length of about 8 millimeters, an outer diameter of about 7.25 millimeters, and an inner diameter (D FTS ), the peripheral wall thickness of the first hollow tubular segment 26 is therefore approximately 2.67 millimeters.

[0218] 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 interior cavity 36 extending from an upstream end 38 of the second hollow tubular segment all the way to a downstream end 40 of the second hollow tubular segment 34. The interior cavity 36 is substantially empty, thereby allowing substantially unrestricted airflow along the interior cavity 36. The second hollow tubular segment 28, and consequently the aerosol cooling element 24, does not substantially contribute to the overall RTD of the aerosol-generating article 10. More specifically, the RTD of the second hollow tubular segment 34 (which is essentially the RTD of the aerosol cooling element 24) is substantially 0 millimeters H2O.

[0219] The second hollow tubular segment 34 has a length of about 8 millimeters, an outer diameter of about 7.25 millimeters, and an inner diameter (D STS ) of the peripheral wall of the second hollow tubular segment 34 is approximately 2 millimeters. FTS ) and the inner diameter (D STS ) is about 0.75.

[0220] The aerosol-generating article 10 includes 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.

[0221] In the embodiment of Figure 6, the downstream section 14 further comprises a mouthpiece element 42 located downstream of the intermediate hollow section 50. More specifically, the mouthpiece element 42 is positioned immediately downstream of the aerosol cooling element 24. As shown in the drawing of Figure 6, the upstream end of the mouthpiece element 42 abuts the downstream end 40 of the aerosol cooling element 18.

[0222] Mouthpiece element 42 is provided in the form of a cylindrical plug of low density cellulose acetate.

[0223] Mouthpiece element 42 has a length of about 12 millimeters and an outer diameter of about 7.25 millimeters. The RTD of mouthpiece element 42 is about 12 millimeters H2O. The ratio of the length of mouthpiece element 42 to the length of intermediate hollow section 50 is about 0.6.

[0224] The rod 12 includes an aerosol-generating substrate in the form of an assemblage of sheets of homogenized tobacco material, although other types of tobacco-containing substrates, such as tobacco cut filler, can replace the assemblage of sheets of homogenized tobacco material.

[0225] The aerosol-generating substrate rod 12 has an outer diameter of about 7.25 millimeters, and a length of about 12 millimeters.

[0226] The aerosol-generating article 10 further comprises a susceptor assembly 44 of the type described above within the rod 12 of the aerosol-generating substrate. More particularly, the susceptor assembly 44 is substantially longitudinally disposed within the aerosol-generating substrate such that the susceptor assembly 44 is substantially parallel to the longitudinal direction of the rod 12. As shown in the drawing of Figure 6, the susceptor assembly 44 is positioned at a radially central location within the rod and effectively extends along the longitudinal axis of the rod 12.

[0227] The susceptor assembly 44 extends completely from the upstream end to the downstream end of the rod 12. In essence, the susceptor assembly 44 has substantially the same length as the rod 12 of the aerosol-generating substrate.

[0228] The upstream section 16 comprises an upstream element 46 located immediately upstream of the rod 12 of the aerosol-generating substrate, the upstream element 46 being longitudinally aligned with the rod 12. In the embodiment of Figure 6, the downstream end of the upstream element 46 abuts the upstream end of the rod 12 of the aerosol-generating substrate. This advantageously prevents the susceptor assembly 44 from becoming dislodged. Furthermore, this ensures that a consumer cannot accidentally come into contact with the heated susceptor assembly 44 during or after use.

[0229] The upstream element 46 is provided in the form of a cylindrical plug of cellulose acetate surrounded by a rigid wrapper. The upstream element 46 has a length of about 5 millimeters. The RTD of the upstream element 46 is about 30 millimeters H2O.

[0230] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like, should be understood in all instances as being modified by the term "about." Also, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically recited herein. Thus, in this context, the number A is understood as A ± 5 percent of A. Within this context, the number A may be considered to include values ​​that are within the typical standard error for the measurement of the property that it modifies. The number A may, in some cases, as used in the appended claims, deviate by the percentages recited above, provided that the amount by which A deviates does not materially affect the basic and novel properties of the claimed invention. Also, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically recited herein.

Claims

1. An aerosol generating article for generating an inhalable aerosol when heated, wherein the aerosol generating article is an aerosol generating rod containing an aerosol generating substrate, Susceptor assembly, At least one strand of susceptor material, which is twisted to be helically arranged around the longitudinal axis of the susceptor assembly, A susceptor assembly comprising an aerosol generating element comprising at least one strand of porous non-tobacco material supporting an aerosol-forming composition containing at least 35 weight percent of an aerosol-forming material, The at least one strand of the aerosol generating element is twisted with the at least one strand of the susceptor material, An aerosol generating article in which the susceptor assembly is thermally bonded to the aerosol generating substrate, the susceptor assembly extends in the longitudinal direction within the aerosol generating rod, and is embedded within the aerosol generating substrate.

2. The aerosol generating article according to claim 1, wherein the at least one strand of susceptor material includes two or more strands of susceptor material twisted together such that the two or more strands of susceptor material are helically arranged around the longitudinal axis of the susceptor assembly and the at least one strand of the aerosol generating element twists with the two or more strands of susceptor material.

3. The aerosol generating article according to claim 2, wherein the at least one strand of the aerosol generating element is also helically arranged around the longitudinal axis of the susceptor assembly and is held in place by being sandwiched between at least two of the two or more strands of the susceptor material.

4. The aerosol generating article according to claim 2, wherein at least one strand of the aerosol generating element extends substantially parallel to the longitudinal axis of the susceptor assembly, defining the core of the susceptor assembly, and two or more strands of the susceptor material are arranged helically around the at least one strand of the aerosol generating element.

5. The aerosol generating article according to claim 1, wherein at least one strand of the susceptor material is a metal flake, filament, pin, or wire.

6. The aerosol-generating article according to claim 1, wherein the aerosol-forming composition is adsorbed onto, coated, impregnated into, or otherwise loaded onto a porous material.

7. The aerosol generating article according to claim 1, wherein the equivalent diameter of at least one aerosol generating article of the susceptor assembly is 0.3 mm to 1.5 mm.

8. The aerosol generating article according to claim 2, wherein the susceptor assembly further comprises one or more spacer elements of a nonconductive material, the one or more spacer elements are configured to create a gap between two adjacent strands of the two or more susceptor material strands such that portions of the two adjacent strands of the two or more susceptor material strands are at a predetermined distance from each other.

9. The aerosol generating article according to claim 8, comprising a secondary aerosol generating substrate provided in at least one of the predetermined gaps.

10. The aerosol generating article according to claim 8, wherein the one or more spacer elements include beads provided on one of the two or more strands of susceptor material.

11. The aerosol generating article according to claim 8, wherein the one or more spacer elements comprises a plate having one or more openings, the plate being arranged transversely to the longitudinal axis of the susceptor assembly, and each of the one or more openings is adapted to receive a corresponding strand of the two or more susceptor materials.

12. The aerosol generating article according to claim 11, wherein the plate is circular and the one or more openings are evenly spaced around the longitudinal axis.

13. The aerosol generating article according to claim 11, wherein the one or more spacer elements comprises a plurality of plates evenly spaced along the length of the susceptor assembly, and each plate comprises one or more openings.

14. An aerosol generating system comprising a heating device and an aerosol generating article according to any one of claims 1 to 13.

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