Stable wrapper for aerosol generating article

Abstract

To provide a wrapper used in aerosol generating articles.SOLUTION: An aerosol generating article 10 includes an aerosol generating substrate 12 comprising nicotine, and a wrapper 50 disposed about the aerosol generating substrate. The wrapper includes a paper layer having a thickness / grammage of about 1.2 micrometers / gsm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to wrappers for use in aerosol-generating articles, which wrappers have a high paper density and may be utilized with aerosol-generating substrates. [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 aerosol-generating articles, an aerosol is generated by transferring heat from a heat source to a physically separate 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] The paper used to wrap the aerosol-generating substrate can absorb aerosol formers, water, and other liquid compounds found in mainstream smoke or aerosol passing through the aerosol-generating article, or moisture or water around the paper. The absorbed liquids can stain or weaken the paper and adversely affect the appearance and structural integrity of the aerosol-generating article. Heated aerosol-generating articles are particularly susceptible to wetting and breakage due to the high levels of aerosol formers in the aerosol-generating substrates of these heated aerosol-generating articles. Heated aerosol-generating articles are particularly prone to swelling as aerosol components are absorbed by the wrapper, leading to difficulties in removal from the heating device. Heated aerosol-generating articles are particularly prone to breaking when they are tightly received and then subsequently removed from the heating device.

[0004] It would be desirable to provide a rolled aerosol-generating substrate that is visually and mechanically stable, particularly for aerosol-generating articles that contain high levels of liquid former or aerosol former.

[0005] It would be desirable to provide an aerosol-generating article that includes a wrapper that does not expand upon absorbing water or compounds contained in the aerosol-generating substrate.

[0006] It would be desirable to provide an aerosol-generating article that includes a wrapper that provides a grease barrier to grease compounds contained in the aerosol-generating substrate.

[0007] It would also be desirable for the wrapper not to affect the taste of the aerosol generated by the aerosol-generating article.

[0008] It would also be desirable for the wrapper not to readily burn when placed in close proximity to a heating element. Summary of the Invention

[0009] SUMMARY OF THE INVENTION It may be an object of the present invention to at least partially address one or more of the desirable technical advantages set forth above.

[0010] According to the present disclosure, there is provided an aerosol-generating article comprising an aerosol-generating substrate containing nicotine and a wrapper disposed around the aerosol-generating substrate, the wrapper comprising a paper layer having a thickness / basis weight of about 1.2 micrometers / gsm or less.

[0011] According to the present disclosure, there is provided an aerosol-generating article comprising an aerosol-generating substrate containing nicotine and at least about 10% aerosol former (including glycerin), and a wrapper disposed around and in contact with the aerosol-generating substrate, the wrapper comprising a paper layer having a thickness / basis weight of about 1.2 micrometers / gsm or less.

[0012] According to the present disclosure, there is provided an aerosol-generating article. The aerosol-generating article may include an aerosol-generating substrate. The aerosol-generating substrate may include a wrapper. The wrapper may be disposed around the aerosol-generating substrate. The wrapper includes a paper layer having a thickness / basis weight of about 1.2 micrometers / gsm or less.

[0013] The paper layer preferably has a thickness / basis weight in the range of about 1.0 micrometer / gsm to about 1.2 micrometer / gsm. The paper layer may have a thickness of less than about 50 micrometers, or less than about 40 micrometers. The wrapper includes a paper layer having a basis weight in the range of about 25 gsm to about 45 gsm, or about 35 gsm to about 40 gsm.

[0014] The paper layer preferably has a thickness / basis weight of about 1.2 micrometers / gsm or less and a water contact angle of at least about 30 degrees. The paper layer may have a water contact angle of at least about 40 degrees, or at least about 45 degrees.

[0015] The term "MD" refers to the machine direction of the wrapper. The machine direction is the direction in which the paper stock flows into and through the papermaking machine. The machine direction is the circumferential direction of the roll of paper as it is wound from the paper machine. The machine direction is also sometimes called the grain direction.

[0016] The term "CD" refers to the cross direction of the wrapper. The cross direction of the wrapper is the direction within the plane of the wrapper. The cross direction of the wrapper is perpendicular to the machine direction of the wrapper.

[0017] The paper layer may have a CD / MD elongation ratio at break of about 2.5 or less. The paper layer may have a CD / MD elongation ratio at break of about 2.2 or less, or about 2 or less. The paper layer may have a CD / MD elongation ratio at break in the range of about 1.8 to 2.2.

[0018] The wrapper preferably comprises a paper layer having a thickness / basis weight of about 1.2 micrometers / gsm or less and having a negative result to at least one kit oil sample of Method Tappi 559cm-02 Classical Method 2002. The paper layer may have a negative result to at least five kit oil samples, or all ten kit oil samples of Method Tappi 559cm-02 Classical Method 2002.

[0019] The wrapper includes two paper layers, a first paper layer having a first thickness / basis weight value and a second paper layer having a second thickness / basis weight value, the first thickness / basis weight value being preferably less than the second thickness / basis weight value. The first thickness / basis weight value may be less than 1.2 micrometers / gsm, and the wrapper may have a total thickness of less than about 80 micrometers.

[0020] The paper layer preferably comprises PVOH (polyvinyl alcohol) or silicone. The paper layer may also comprise a surface treatment comprising PVOH or silicone. The addition of PVOH (polyvinyl alcohol) or silicone may improve the grease barrier properties of the wrapper.

[0021] The term "silicone" refers to siloxane. Preferably, the silicone or siloxane comprises polydimethylsiloxane.

[0022] Preferably, the aerosol-generating substrate may comprise a homogenized tobacco material, which may comprise, on a dry weight basis, a tobacco material, about 1% to about 5% of a binder, and about 5% to about 30% of an aerosol former.

[0023] Preferably, the aerosol-generating substrate may comprise a gel composition. The gel composition may comprise a major amount (by weight) of glycerin. The gel composition may comprise xanthan gum.

[0024] Preferably, the aerosol-generating substrate may comprise a metallic induction heating element. The metallic induction heating element may comprise a plurality of metallic induction heating elements. The metallic induction heating element may comprise a metallic induction heating ring element.

[0025] The wrapper may be formed from a single layer of paper. The wrapper may be formed from two layers of paper. The wrapper may be formed from three or more layers of paper.

[0026] The wrapper preferably covers at least 20%, at least 50%, at least 80%, at least 90%, at least 95%, at least 99%, or preferably substantially the entire length of the aerosol-generating substrate. The wrapper preferably covers the entire aerosol-generating substrate and does not extend beyond the aerosol-generating substrate.

[0027] When the wrapper has two or more paper layers, a first paper layer may have the unique properties described herein, and a second paper layer may be considered a conventional paper layer. The second paper layer may preferably be disposed on the outside of the first paper layer. Alternatively, the first paper layer may be disposed on the outside of the second paper layer. The first paper layer having the unique properties described herein is preferably in contact with the aerosol-forming substrate.

[0028] When the wrapper has two or more paper layers, the first paper layer may have the specific properties described herein, and the second paper layer may also have the specific properties described herein. All paper layers forming the wrapper may have the specific properties described herein. In particular, one or both paper layers forming the wrapper may include PVOH (polyvinyl alcohol) or silicone. One or both paper layers forming the wrapper may include a surface treatment including PVOH or silicone.

[0029] Advantageously, aerosol-generating articles including the wrappers described herein may reduce absorption of moisture, water, aerosol formers, or grease in the smoke or aerosol passing through the aerosol-generating article. As a result, swelling, visible staining, and physical weakening of the wrapper portion of the aerosol-generating article may be reduced, even when high levels of aerosol formers are included in the aerosol-generating substrate.

[0030] Advantageously, the aerosol-generating article provides a visually and mechanically stable, rolled aerosol-generating substrate that avoids expansion. This is particularly useful for heated, non-combustion aerosol-generating articles that may be inserted into a heating device. The aerosol-generating article wrapper resists combustion when in close proximity to a heating element, and therefore, an induction heating element may be incorporated throughout the aerosol-generating substrate.

[0031] The term "aerosol-generating article" is used herein to mean an article in which an aerosol-generating substrate is heated to generate and deliver to a consumer an inhalable aerosol. As used herein, the term "aerosol-generating substrate" means a substrate capable of releasing a volatile compound upon heating to generate an aerosol.

[0032] A conventional cigarette is lit when a user applies a flame to one end of the cigarette and draws air through the other end. The localized heat provided by the flame and oxygen from the air drawn through the cigarette cause 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). 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 substrate. For example, the aerosol-generating article according to the present disclosure finds particular application in aerosol-generating systems comprising an electrically heated aerosol generator having an internal heater blade adapted to be inserted into a rod of the aerosol-generating substrate. Aerosol-generating articles of this type have been described in the prior art, for example, in European Patent No. EP 0 822 670.

[0033] 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.

[0034] As used herein, the term "aerosol-generating system" refers to the combination of an aerosol-generating device and an aerosol-generating article.

[0035] The term "aerosol-generating substrate" refers to a material capable of generating or emitting an aerosol. The aerosol-generating substrate may be a solid, paste, gel, slurry, liquid, or may comprise any combination of solid, paste, gel, slurry, and liquid compounds. Preferably, the aerosol-generating substrate is a solid or gel composition. The aerosol-generating substrate may preferably comprise nicotine.

[0036] The aerosol-generating article may comprise an aerosol-generating substrate and a mouthpiece. The mouthpiece may comprise a filter. A tipping wrapper may attach the filter to the aerosol-generating substrate.

[0037] The aerosol-generating substrate may be a solid composition. The composition may include a plant-based material. The aerosol-generating substrate may include tobacco, which preferably contains volatile tobacco flavor compounds that are released from the aerosol-generating substrate upon heating. The aerosol-generating substrate may include a homogenized tobacco material, an aerosol former, and a binder.

[0038] Nicotine may be present in the aerosol-generating substrate in the range of about 0.5 to about 10% by weight of nicotine, or about 0.5 to about 5% by weight of nicotine. Preferably, the aerosol-generating substrate contains about 1 to about 3% by weight of nicotine, or about 1.5 to about 2.5% by weight of nicotine, or about 2% by weight of nicotine.

[0039] The aerosol-generating substrate may include a flavoring agent. The plant material provides a flavoring agent that may impart flavor to the taste of the aerosol generated by the aerosol-generating article. A flavoring agent is any natural or artificial compound that affects the organoleptic qualities of the aerosol. Non-limiting examples of sources of flavoring agents include mint (such as peppermint and spearmint), coffee, tea, cinnamon, clove, cocoa, vanilla, eucalyptus, geranium, agave, and juniper, and combinations thereof.

[0040] The aerosol-generating substrate may contain an essential oil. The essential oil may provide a flavoring agent that may impart flavor to the taste of the aerosol generated by the aerosol-generating article. Suitable essential oils include, but are not limited to, eugenol, peppermint oil, and spearmint oil. A preferred essential oil is eugenol. The essential oil may be present in the aerosol-generating substrate in an amount of at least about 0.1% by weight, or at least about 0.5% by weight, or at least about 1% by weight. The essential oil may be present in the aerosol-generating substrate in a range of about 0.1% by weight to about 10% by weight, or about 0.1% by weight to about 5% by weight, or about 0.5% by weight to about 2% by weight.

[0041] The aerosol-generating substrate may include a gel composition. The term "gel" refers to a solid at room temperature. In this context, "solid" means that the gel has a stable size and shape and does not flow. In this context, room temperature means 25 degrees Celsius. A gel may be defined as a substantially dilute system that does not exhibit flow at steady state. By weight, gels may be mostly liquid, yet they behave like a solid due to a three-dimensional crosslinked network within the liquid. The crosslinks within the fluid give the gel its structure (hardness). In this way, a gel may be a dispersion of liquid molecules within a solid, with liquid particles dispersed within a solid medium.

[0042] The gel composition may include a gelling agent that forms a solid medium, an aerosol former such as glycerin dispersed in the solid medium, and nicotine dispersed in the glycerin. The composition forms a stable gel phase. The gel composition may include at least two gelling agents that form a solid medium, glycerin dispersed in the solid medium, and nicotine dispersed in the glycerin. The composition forms a stable gel phase. The gel composition may include a thickener, a gelling agent that forms a solid medium, glycerin dispersed in the solid medium, and nicotine dispersed within the glycerin. The composition forms a stable gel phase. The gel composition may include nicotine, an aerosol former, a thickener, a hydrogen-bond crosslinking gelling agent, and an ion-crosslinking gelling agent. The gel composition may further include a divalent cation.

[0043] The term "thickener" refers to a compound that, when uniformly added in an amount of 0.3% by weight to a 50% by weight water / 50% by weight glycerin mixture at 25° C., increases the viscosity without resulting in the formation of a gel, and causes the mixture to remain in a fluid state or to remain fluid. Preferably, a thickener refers to a compound that, when uniformly added in an amount of 0.3% by weight to a 50% by weight water / 50% by weight glycerin mixture at 25° C., increases the viscosity by at least 50 cPs, preferably by at least 200 cPs, preferably by at least 500 cPs, preferably by at least 1000 cPs, at a shear rate of 0.1 s-1, without resulting in the formation of a gel, and causes the mixture to remain in a fluid state or to remain fluid. Preferably, a thickener refers to a compound that, when uniformly added in an amount of 0.3% by weight to a 50% by weight water / 50% by weight glycerin mixture at 25°C, increases the viscosity at a shear rate of 0.1 s-1 by at least 2 times, or at least 5 times, or at least 10 times, or at least 100 times higher than before addition without causing the formation of a gel, and the mixture remains in a fluid state or remains fluid.

[0044] The viscosity values ​​listed herein can be measured using a Brookfield RVT viscometer with a disc type RV#2 spindle rotating at 25°C at a speed of 6 revolutions per minute (rpm).

[0045] The term "gelling agent" refers to a compound that, when added in an amount of about 0.3% by weight to a 50% by weight water / 50% by weight glycerin mixture, forms a solid medium or support matrix that uniformly leads to a gel. Gelling agents include, but are not limited to, hydrogen-bond cross-linking gelling agents and ionic cross-linking gelling agents.

[0046] The term "hydrogen-bond cross-linking gelator" refers to a gelator that forms non-covalent or physical cross-links via hydrogen bonds. Hydrogen bonds are not covalent bonds to hydrogen atoms, but rather a type of electrostatic dipole-dipole attraction between molecules. They result from the attraction between a hydrogen atom covalently bonded to another extremely electronegative atom, such as an N, O, or F atom, and another extremely electronegative atom.

[0047] The term "ionically cross-linking gelator" refers to a gelator that forms non-covalent or physical cross-links through ionic bonds. Ionic cross-linking involves the association of polymer chains through non-covalent interactions. A cross-linked network is formed when multivalent molecules with opposite charges are electrostatically attracted to each other, resulting in a cross-linked polymer network.

[0048] The gel composition includes an aerosol former. Ideally, the aerosol former is substantially resistant to thermal decomposition at the operating temperature of the associated aerosol-generating device. Suitable aerosol formers include, but are not limited to, polyhydric alcohols (e.g., triethylene glycol, 1,3-butanediol, glycerin), esters of polyhydric alcohols (e.g., glycerin monoacetate, diacetate, or triacetate), and aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids (e.g., dimethyl dodecanedioate, dimethyl tetradecanedioate). The polyhydric alcohol or mixture thereof may be one or more of triethylene glycol, 1,3-butanediol, and glycerin (glycerin or propane-1,2,3-triol) or polyethylene glycol. Preferably, the aerosol former is glycerin.

[0049] The gel composition may include a large amount of an aerosol former, such as glycerin. The gel composition may include a mixture of water and glycerin, where glycerin forms a majority (by weight) of the gel composition. Glycerin may form at least about 50% by weight of the gel composition. Glycerin may form at least about 60%, or about 65%, or about 70% by weight of the gel composition. Glycerin may form about 70% to about 80% by weight of the gel composition. Glycerin may form about 70% to about 75% by weight of the gel composition.

[0050] Preferably, the gel composition contains no water or only low levels of water. When the gel composition contains no water or only low levels of water, the gel composition may contain higher levels of aerosol formers, gelling agents, thickeners, and other compounds, such as nicotine. Water-free or low-level gel compositions are also simpler and require less energy to vaporize. Aerosols formed from water-free or low-level gel compositions may be perceived by users as being less hot. The gel composition preferably contains less than about 40% water by weight, preferably less than about 30% water by weight, and preferably less than about 25% water by weight. The gel composition may contain less than about 20% water by weight, or less than about 15% water by weight, or less than about 10% water by weight, or less than about 5% water by weight. It may be preferable for the gel composition to contain some water. When the composition contains some water, the gel composition is more stable. The gel composition preferably contains at least about 1% water by weight, or at least about 2% water by weight, or at least about 5% water by weight. The gel composition preferably contains at least about 10% by weight, or at least about 15% by weight, of water, and preferably contains in the range of about 15% to about 25% by weight of water.

[0051] The gel composition may include a gelling agent that is a hydrogen-bond cross-linking gelling agent and an ionic cross-linking gelling agent. The gel composition may further include a thickening agent. The gelling agent may form a solid medium in which the aerosol former may be dispersed. The gelling agent may form a solid medium in which the aerosol former and water may be dispersed. The thickening agent in combination with the hydrogen-bond cross-linking gelling agent and the ionic cross-linking gelling agent surprisingly appears to support the solid medium and maintain the gel composition even when the gel composition includes high levels of glycerin.

[0052] The gel composition may contain about 0.4% to about 10% by weight of gelling agent. Preferably, the composition may contain about 0.5% to about 8% by weight of gelling agent. Preferably, the composition may contain about 1% to about 6% by weight of gelling agent. Preferably, the composition may contain about 2% to about 4% by weight of gelling agent. Preferably, the composition may contain about 2% to about 3% by weight of gelling agent. The gel composition may contain about 0.2% to about 5% by weight of thickener. About 0.5% to about 3% by weight of thickener is preferred. About 0.5% to about 2% by weight of thickener is preferred. About 1% to about 2% by weight of thickener is preferred.

[0053] The gel composition may comprise a thickener, a hydrogen-bond cross-linking gelling agent, and an ionic cross-linking gelling agent present in the gel composition in a total amount of about 1% to about 8% by weight. Preferably, the gel composition may comprise a thickener, a hydrogen-bond cross-linking gelling agent, and an ionic cross-linking gelling agent present in the gel composition in a total amount of about 2% to about 6% by weight. Preferably, the gel composition may comprise a thickener, a hydrogen-bond cross-linking gelling agent, and an ionic cross-linking gelling agent present in the gel composition in a total amount of about 3% to about 5% by weight.

[0054] The gel composition may comprise a thickener, a hydrogen-bond cross-linking gelling agent, and an ionic cross-linking gelling agent, each independently present in the gel composition within a range of about 0.3% to about 3% by weight. Preferably, the gel composition may comprise a thickener, a hydrogen-bond cross-linking gelling agent, and an ionic cross-linking gelling agent, each independently present in the gel composition within a range of about 0.5% to about 2% by weight. Preferably, the gel composition may comprise a thickener, a hydrogen-bond cross-linking gelling agent, and an ionic cross-linking gelling agent, each independently present in the gel composition within a range of about 1% to about 2% by weight.

[0055] The thickening agent may comprise one or more of xanthan gum, carboxymethylcellulose, microcrystalline cellulose, methylcellulose, gum arabic, guar gum, lambda carrageenan, or starch. Preferably, the thickening agent comprises xanthan gum.

[0056] The gel composition may contain a thickener (such as xanthan gum) in the range of about 0.2% to about 5% by weight. Preferably, the xanthan gum may be in the range of about 0.5% to about 3% by weight. Preferably, the xanthan gum may be in the range of about 0.5% to about 2% by weight. Preferably, the xanthan gum may be in the range of about 1% to about 2% by weight.

[0057] The hydrogen-bond cross-linking gelling agent may comprise one or more of galactomannan, gelatin, agarose, or konjac gum, or agar. Preferably, the hydrogen-bond cross-linking gelling agent comprises agar.

[0058] The gel composition may contain about 0.3% to about 5% by weight of a hydrogen-bond cross-linking gelling agent (such as agar). Preferably, the composition may contain about 0.5% to about 3% by weight of a hydrogen-bond cross-linking gelling agent. Preferably, the composition may contain about 1% to about 2% by weight of a hydrogen-bond cross-linking gelling agent.

[0059] The ionic cross-linking gelling agent may comprise low acyl gellan, pectin, kappa carrageenan, iota carrageenan or alginate. It may be preferred that the ionic cross-linking gelling agent comprises low acyl gellan.

[0060] The gel composition may contain about 0.3% to about 5% by weight of an ionically cross-linked gelling agent (such as low-acyl gellan). Preferably, the composition may contain about 0.5% to about 3% by weight of an ionically cross-linked gelling agent. Preferably, the composition may contain about 1% to about 2% by weight of an ionically cross-linked gelling agent.

[0061] The gel composition may further comprise a divalent cation. Preferably, the divalent cation may comprise calcium ions, such as calcium lactate in solution. The divalent cation (e.g., calcium ions) may assist in gel formation in compositions that include a gelling agent, such as an ionically crosslinking gelling agent. The ionic effect may assist in gel formation. The divalent cation may be present in the gel composition in a range of about 0.1 to about 1 wt. %, or about 0.5 wt. %.

[0062] The gel composition may further comprise an acid. The acid may comprise a carboxylic acid. The carboxylic acid may comprise a ketone group. Preferably, the carboxylic acid may comprise a ketone group having less than about 10 carbon atoms, or less than about 6 carbon atoms, or less than about 4 carbon atoms, such as levulinic acid or lactic acid. Preferably, the carboxylic acid has three carbon atoms (such as lactic acid). Lactic acid surprisingly improves the stability of the gel composition over similar carboxylic acids. The carboxylic acid may aid in gel formation. The carboxylic acid may reduce the change in nicotine concentration in the gel composition during storage.

[0063] The gel composition may contain a carboxylic acid (such as lactic acid) in the range of about 0.1% to about 5% by weight. Preferably, the carboxylic acid may be in the range of about 0.5% to about 3% by weight. Preferably, the carboxylic acid may be in the range of about 0.5% to about 2% by weight. Preferably, the carboxylic acid may be in the range of about 1% to about 2% by weight.

[0064] Nicotine is included in the gel composition. Nicotine may be added to the composition in free base or salt form. The gel composition may contain about 0.5 to about 10% by weight nicotine, or about 0.5 to about 5% by weight nicotine. Preferably, the gel composition may contain about 1 to about 3% by weight nicotine, or about 1.5 to about 2.5% by weight nicotine, or about 2% by weight nicotine. The nicotine component of the gel formulation may be the most volatile component of the gel formulation. In some embodiments, water may be the most volatile component of the gel formulation, and the nicotine component of the gel formulation may be the second most volatile component of the gel formulation.

[0065] The aerosol-generating system may comprise a heat source, an aerosol-generating substrate, at least one air inlet downstream of the aerosol-generating substrate, and an airflow path extending between the at least one air inlet and the mouth end of the article. The heat source is preferably upstream of the aerosol-generating substrate. The heat source may be integral with the aerosol-generating device, or the consumable aerosol-generating article may be releasably received within the aerosol-generating device.

[0066] The heat source may be a combustible heat source, a chemical heat source, an electrical heat source, a heat sink, or any combination thereof. The heat source may be an electrical heat source, preferably shaped in the form of a blade that can be inserted into the aerosol-generating substrate. Alternatively, the heat source may be configured to surround the aerosol-generating substrate, and thus may be in the form of a hollow cylinder, or any other such suitable form. Alternatively, the heat source is a combustible heat source. As used herein, a combustible heat source is a heat source that burns itself during use to generate heat, but which, unlike cigarettes, cigars, or cigarillos, does not involve the combustion of the aerosol-generating substrate. The combustible heat source may comprise carbon and an ignition aid such as a metal peroxide, superoxide, or nitrate, where the metal is an alkali metal or alkaline earth metal.

[0067] The aerosol-generating substrate may comprise an induction heating element or susceptor, or a plurality of induction heating elements or susceptors. The induction heating element or susceptor heats in the presence of an alternating or fluctuating electromagnetic field. When heating is by induction heating, the fluctuating electromagnetic field is transmitted through the aerosol-generating article to the induction heating element or susceptor, causing the susceptor or induction heating element to convert the fluctuating field into thermal energy, thereby heating the aerosol-generating substrate.

[0068] The induction heating element or susceptor may be formed from any material that can be inductively heated to a temperature sufficient to generate an aerosol from the aerosol-generating substrate. The induction heating element or susceptor may comprise metal or carbon. A preferred induction heating element or susceptor may comprise a ferromagnetic material (e.g., ferritic iron), or ferromagnetic steel or stainless steel. The induction heating element or susceptor may comprise aluminum. The induction heating element or susceptor may be formed from 400 series stainless steel, such as grade 410, grade 420, or grade 430 stainless steel. Different materials dissipate different amounts of energy when placed in an electromagnetic field of similar frequency and field strength. The induction heating element or susceptor is preferably heated to a temperature above 250°C. However, the induction heating element or susceptor is preferably heated to less than 350°C to prevent combustion of materials in contact with the susceptor.

[0069] An induction heating element or susceptor may be located in close proximity to the wrapper of the aerosol-generating substrate, as the wrappers described herein advantageously resist combustion.

[0070] The term "mouthpiece" is used herein to refer to the portion of the aerosol-generating article that is designed to come into contact with the consumer's mouth. The mouthpiece can be a portion of the aerosol-generating article that may include a filter, or in some cases, the mouthpiece can be defined by the extent of the tipping wrapper. In other cases, the mouthpiece can be defined as a portion of the aerosol-generating article that extends approximately 40 mm from the mouth end of the aerosol-generating article, or that extends approximately 30 mm from the mouth end of the aerosol-generating article.

[0071] The terms "upstream" and "downstream" refer to the relative positions of elements of the aerosol-generating article described with respect to the direction of the aerosol as it is drawn from the aerosol-generating substrate and through the mouthpiece.

[0072] The terms "wrapper" or "paper wrapper" are interchangeable and refer to one or more layers of wrapping material, formed of paper, that surrounds the aerosol-generating substrate to contain it or to maintain the shape of the aerosol-generating article. The wrapper reduces staining on the exterior surface of the aerosol-generating article. The wrapper is preferably in contact with the aerosol-generating substrate.

[0073] The term "hydrophobic" refers to a surface that exhibits water-repellent properties. One useful way to determine this is to measure the water contact angle. The "water contact angle" is the angle, traditionally measured through a liquid, where a liquid / vapor interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid via Young's equation. The present disclosure relates to a wrapper for use in an aerosol-generating article, the wrapper having a paper layer with high density and may be used in conjunction with an aerosol-generating substrate. According to the present disclosure, an aerosol-generating article is provided, comprising an aerosol-generating substrate containing nicotine and a wrapper disposed around the aerosol-generating substrate. The wrapper comprises a paper layer with a thickness / basis weight of about 1.2 micrometers / gsm or less.

[0074] The wrapper preferably comprises a paper layer having a thickness / basis weight in the range of about 0.8 micrometers / gsm to about 1.2 micrometers / gsm. The paper layer may have a thickness / basis weight in the range of about 1.0 micrometers / gsm to about 1.2 micrometers / gsm. The paper layer may have a thickness / basis weight of about 1.0 micrometers / gsm. The paper layer may have a thickness / basis weight of about 0.9 micrometers / gsm. The paper layer may have a thickness / basis weight of about 1.0 micrometers / gsm. The paper layer may have a thickness / basis weight of about 1.1 micrometers / gsm. The paper layer may have a thickness / basis weight of about 1.2 micrometers / gsm.

[0075] The paper layer may have a thickness of less than about 50 micrometers, or less than about 40 micrometers. The paper layer may have a thickness in the range of about 10 micrometers to about 50 micrometers. The paper layer may have a thickness in the range of about 20 micrometers to about 50 micrometers. The paper layer may have a thickness in the range of about 30 micrometers to about 50 micrometers. The paper layer may have a thickness in the range of about 35 micrometers to about 50 micrometers. The paper layer may have a thickness in the range of about 35 micrometers to about 40 micrometers. The paper layer may have a thickness in the range of about 40 micrometers to about 50 micrometers. The paper layer may have a basis weight in the range of about 25 gsm to about 45 gsm. The paper layer may have a basis weight in the range of about 30 gsm to about 45 gsm. The paper layer may have a basis weight in the range of about 35 gsm to about 45 gsm. The paper layer may have a basis weight in the range of about 35 gsm to about 40 gsm.

[0076] In one embodiment, the paper layer has a basis weight of about 35 gsm and a thickness of about 37 micrometers. The paper layer has a thickness / basis weight value of about 1.06.

[0077] The paper layer preferably comprises PVOH (polyvinyl alcohol) or silicone. In one embodiment, the paper layer comprises PVOH (polyvinyl alcohol). The PVOH may be applied to the paper layer as a surface coating. The PVOH may be disposed on the outer surface of the paper layer of the aerosol-generating article. The PVOH may be disposed on the outer surface of the paper layer of the aerosol-generating article and form a layer thereon. The PVOH may be disposed on the inner surface of the paper layer of the aerosol-generating article. The PVOH may be disposed on the inner surface of the paper layer of the aerosol-generating article and form a layer thereon. The PVOH may be disposed on both the inner and outer surfaces of the paper layer of the aerosol-generating article. The PVOH may be disposed on the inner and outer surfaces of the paper layer of the aerosol-generating article and form a layer thereon.

[0078] The paper layer may include a surface treatment comprising PVOH or silicone. The paper layer may include a surface treatment comprising PVOH. The paper layer may include a surface treatment comprising silicone. The surface treatment may be applied to an outer surface of the paper layer. The surface treatment may be applied to an inner surface of the paper layer. The surface treatment may be applied to both the outer and inner surfaces of the paper layer. The addition of PVOH or silicone may improve the grease barrier properties of the paper layer.

[0079] The aerosol-generating substrate may include a gel composition. The gel composition may include a large amount of an aerosol former, such as glycerin. The gel composition may include nicotine, at least about 50% by weight glycerin or at least 70% by weight glycerin, at least about 0.2% by weight of a hydrogen-bond cross-linking gelling agent, at least about 0.2% by weight of an ionic cross-linking gelling agent, and at least about 0.2% by weight of a thickening agent. The gel composition may include xanthan gum.

[0080] The aerosol-generating substrate may include a homogenized tobacco material, which may include, on a dry weight basis, a tobacco material, about 1% to about 5% of a binder, and about 5% to about 30% of an aerosol former.

[0081] The aerosol-generating substrate may comprise a metallic induction heating element. The metallic induction heating element may comprise a plurality of metallic induction heating elements. The metallic induction heating element may comprise a metallic induction heating ring element.

[0082] It is intended that the wrappers described herein may reduce and prevent the formation of stains on the aerosol-generating article that are visible to the consumer. It has been observed that stains can appear on the aerosol-generating article during storage in a humid environment or during consumption. The stains may be caused by the absorption of water or aerosol formers, including any colored substances suspended or dissolved within the cellulosic fiber web that makes up the wrapper. Without being bound by any theory, it is believed that the water or aerosol formers interact with the cellulosic fibers of the paper and change the fiber texture, resulting in localized changes in optical properties such as brightness, color, and opacity, as well as mechanical properties such as tensile strength and permeability of the wrapper.

[0083] It is contemplated that the wrappers described herein may reduce and even prevent expansion of the aerosol-generating article, which improves the usability of the aerosol-generating article, such that the aerosol-generating article can be reliably inserted and removed from a heating device without damaging the aerosol-generating article.

[0084] The wrapper is a portion of the aerosol-generating article that is disposed around the aerosol-generating substrate to help maintain the cylindrical shape of the aerosol-generating article. The wrapper may contain the aerosol-generating substrate over at least about 50% of the length of the plug of aerosol-generating substrate. Preferably, the wrapper contains the aerosol-generating substrate over at least about 90% of the length of the plug of aerosol-generating substrate. More preferably, the wrapper contains the aerosol-generating substrate over at least about 100% of the length of the plug of aerosol-generating substrate.

[0085] The wrapper may exhibit a range of permeability, including no permeability. The permeability of cigarette paper is determined using the international standard test method ISO 2965:2009, and the results are presented in cubic centimeters per minute per square centimeter, referred to as "Colesta units." The permeability of the wrappers described herein may be within the range of about 1 to about 10 Coresta units, about 5 to about 20 Coresta units, or about 1 to about 5 Coresta units.

[0086] The wrapper may be formed from any cellulosic material, such as paper, wood, fabric, natural and man-made fibers, etc. Preferably, the wrapper does not contain fillers such as calcium carbonate. Preferably, the wrapper is formed from at least 90% by weight cellulosic material. Preferably, the wrapper is formed from at least 95% by weight cellulosic material.

[0087] The paper layer may be formed from any cellulosic material, such as paper, wood, fabric, natural fibers, and artificial fibers. Preferably, the paper layer does not contain fillers such as calcium carbonate. Preferably, the paper layer is formed from at least 90% by weight of cellulosic material. Preferably, the paper layer is formed from at least 95% by weight of cellulosic material.

[0088] The surface of the paper layer may have a water contact angle of at least about 30 degrees, or at least about 35 degrees, at least about 40 degrees, or at least about 45 degrees. The hydrophobicity or water contact angle is determined utilizing the TAPPI T558 test, and the results are presented as interfacial contact angles, also reported in degrees, and can range from approximately 0 degrees to approximately 180 degrees.

[0089] The paper layer may have a CD / MD elongation at break ratio of about 2.5 or less. The paper layer may have a CD / MD elongation at break ratio of about 2.2 or less, or about 2 or less. The term "MD" refers to the machine direction of the paper layer. The machine direction may also be referred to as the grain direction of the paper layer. The term "CD" refers to the cross direction of the paper layer, which is perpendicular to the machine direction of the paper layer.

[0090] The paper layer may have a negative result (no visible stains) to at least one kit oil sample of Method Tappi 559cm-02 Classical Method 2002. The paper layer may have a negative result to at least five kit oil samples, or all ten kit oil samples of Method Tappi 559cm-02 Classical Method 2002.

[0091] The wrapper may include two paper layers, a first paper layer having a first thickness / basis weight value and a second paper layer having a second thickness / basis weight value, the first thickness / basis weight value being less than the second thickness / basis weight value. The first thickness / basis weight value may be less than 1.2 micrometers / gsm, and the wrapper has a total thickness of less than about 80 micrometers.

[0092] The wrapper may include two paper layers, a first layer in contact with the aerosol-forming substrate and a second layer overlying the first layer and forming the outer surface of the aerosol-forming article, The first layer may have a first thickness / basis weight value less than 1.2 micrometers / gsm and the second layer may have a second thickness / basis weight value greater than 1.2 micrometers / gsm.

[0093] The wrapper may include two paper layers, a first layer in contact with the aerosol-forming substrate and a second layer overlying the first layer and forming the outer surface of the aerosol-forming article, The first layer may have a first thickness / basis weight value less than 1.2 micrometers / gsm, and the second layer may have a second thickness / basis weight value less than 1.2 micrometers / gsm.

[0094] The wrapper may comprise two paper layers, with the first layer in contact with the aerosol-forming substrate and the second layer overlying the first. The first layer may comprise PVOH (polyvinyl alcohol) or silicone, or may comprise a surface treatment including PVOH or silicone. The second layer may comprise PVOH (polyvinyl alcohol) or silicone, or may comprise a surface treatment including PVOH or silicone. Both the first and second layers may comprise PVOH (polyvinyl alcohol) or silicone, or may comprise a surface treatment including PVOH or silicone. Only the first layer may comprise PVOH (polyvinyl alcohol) or silicone, or may comprise a surface treatment including PVOH or silicone. Only the second layer may comprise PVOH (polyvinyl alcohol) or silicone, or may comprise a surface treatment including PVOH or silicone.

[0095] The aerosol-generating article includes an aerosol-generating substrate, which may include a tobacco load surrounded by a wrapper as described herein. The aerosol-generating substrate may include any suitable type(s) of tobacco material or tobacco substitute in any suitable form. The aerosol-generating substrate may include full-cured tobacco, Burley tobacco, Maryland tobacco, Oriental tobacco, specialty tobacco, homogenized tobacco, or reconstituted tobacco, or any combination thereof. The aerosol-generating substrate may be provided in the form of tobacco cut filler, tobacco lamina, processed tobacco material such as volume-expanded or puffed tobacco, processed tobacco stems such as cut-rolled or cut-puffed stems, homogenized tobacco, reconstituted tobacco, cast leaf tobacco, or blends thereof, and the like. The term "tobacco cut filler" is used herein to refer to tobacco material primarily formed from the lamina portion of tobacco leaves. The term "tobacco cut filler" is used herein to refer to both a single species of the genus Nicotiana and two or more species of the genus Nicotiana that form a tobacco cut filler blend.

[0096] As used herein, the term "homogenized tobacco" refers to a material formed by agglomerating particulate tobacco. Homogenized tobacco may include reconstituted tobacco or cast leaf tobacco, or a mixture of both. The term "reconstituted tobacco" refers to a paper-like material that can be made from tobacco by-products such as tobacco fines, tobacco dust, tobacco stems, or a mixture of the foregoing. Reconstituted tobacco can be made by extracting soluble chemicals in the tobacco by-product, processing the remaining tobacco fibers into a sheet, and then re-coating the extracted material in concentrated form onto the sheet. The term "cast leaf tobacco" is used herein to refer to a product resulting from a process well known in the art, which involves casting a slurry containing ground tobacco particles and a binder (e.g., guar) onto a support surface (such as a belt conveyor), drying the slurry, and removing the dried sheet from the support surface. Exemplary methods for producing these types of aerosol-generating substrates are described in U.S. Patent Nos. 5,724,998, 5,584,306, 4,341,228, 5,584,306, and 6,216,706. The homogenized tobacco may be crimped, reeled, folded, or otherwise compressed into a sheet before being rolled to form a rod. For example, homogenized tobacco material sheets for use in the present invention may be crimped using a crimping unit of the type described in Swiss Patent No. 691156, which includes a pair of rotatable crimping rollers. However, it will be appreciated that homogenized tobacco material sheets for use in the present invention may also be textured using other suitable machinery and processes that deform or perforate the homogenized tobacco material sheet.

[0097] Aerosol-generating substrates used in aerosol-generating articles generally contain higher levels of aerosol former(s) than combustible smoking articles such as cigarettes. Humectants can also be referred to as "aerosol formers." Aerosol former is used to describe any suitable known compound or mixture of compounds that facilitates aerosol formation during use and is substantially resistant to thermal decomposition at the operating temperature of the aerosol-generating substrate. Suitable aerosol formers are known in the art and include, but are not limited to, polyhydric alcohols (e.g., propylene glycol, triethylene glycol, 1,3-butanediol, glycerin), esters of polyhydric alcohols (e.g., glycerin monoacetate, diacetate, triacetate), and aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids (e.g., dimethyl dodecanedioate, dimethyl tetradecanedioate). Preferred aerosol formers are polyhydric alcohols or mixtures thereof (e.g., propylene glycol, triethylene glycol, 1,3-butanediol), and most preferably glycerin or glycerin. The aerosol-generating substrate may comprise a single aerosol former, or alternatively, the aerosol-generating substrate may comprise a combination of two or more aerosol formers.

[0098] The aerosol-generating substrate may have a high level of aerosol former. As used herein, a high level of aerosol former means an aerosol former content of greater than about 10% by weight, or preferably greater than about 15% by weight, or more preferably greater than about 20% by weight. The aerosol-generating substrate may also have an aerosol former content of about 10% to about 30% by weight, about 15% to about 30% by weight, or about 20% to about 30% by weight. The aerosol-generating substrate may also have a glycerin content of about 10% to about 30% by weight, about 15% to about 30% by weight, or about 20% to about 30% by weight.

[0099] The aerosol-generating substrate may comprise at least about 1% by weight, or at least about 2% by weight, or at least about 5% by weight, or at least about 7% by weight, or at least about 10% by weight, or at least about 12% by weight, or at least about 15% by weight, or at least about 18% by weight of aerosol formers. The aerosol-generating substrate may comprise from about 1 to about 20% by weight, or from about 5 to about 20% by weight, or from about 10 to about 20% by weight of aerosol formers.

[0100] The aerosol-generating substrate may comprise at least about 1% by weight, or at least about 2% by weight, or at least about 5% by weight, or at least about 7% by weight, or at least about 10% by weight, or at least about 12% by weight, or at least about 15% by weight, or at least about 18% by weight of glycerin. The aerosol-generating substrate may comprise from about 1 to about 20% by weight, or from about 5 to about 20% by weight, or from about 10 to about 20% by weight of glycerin.

[0101] The aerosol-generating substrate in gel form may have a large amount of an aerosol former, preferably glycerin. The gel composition may include a gelling agent forming a solid medium, an aerosol former such as glycerin dispersed in the solid medium, and nicotine dispersed in the glycerin. The composition forms a stable gel phase. The gel composition may include at least two gelling agents forming a solid medium, glycerin dispersed in the solid medium, and nicotine dispersed in the glycerin. The composition forms a stable gel phase. The gel composition may include a thickener, a gelling agent forming a solid medium, glycerin dispersed in the solid medium, and nicotine dispersed within the glycerin. The composition forms a stable gel phase. The gel composition may include nicotine, an aerosol former, a thickener, a hydrogen-bond crosslinking gelling agent, and an ion-crosslinking gelling agent. The gel composition may further include a divalent cation.

[0102] The gel composition may include a large amount of an aerosol former, such as glycerin. The gel composition may include a mixture of water and glycerin, where glycerin forms a majority (by weight) of the gel composition. Glycerin may form at least about 50% by weight of the gel composition. Glycerin may form at least about 60%, or about 65%, or about 70% by weight of the gel composition. Glycerin may form about 70% to about 80% by weight of the gel composition. Glycerin may form about 70% to about 75% by weight of the gel composition.

[0103] The wrapper described herein is disposed around the aerosol-generating substrate and can reduce absorption of the aerosol-forming compound and water into the wrapper when air is drawn through the heated aerosol-generating article.

[0104] Preferably, the aerosol-generating article may be generally cylindrical, which allows for a smooth flow of the aerosol. The aerosol-generating article may have an outer diameter of, for example, 4 to 15 millimeters, 5 to 10 millimeters, or 6 to 8 millimeters. The aerosol-generating article may have a length of, for example, 10 to 60 millimeters, 15 to 50 millimeters, or 20 to 45 millimeters.

[0105] The resistance to draw (RTD) of an aerosol-generating article varies depending on, among other factors, the length and dimensions of the passageway, the size of the opening, the dimensions of the most constricted cross-sectional area of ​​the interior passageway, and the materials used. The RTD of the aerosol-generating article may be 50 millimeters of water (mm H2O) to 140 millimeters of water (mm H2O), 60 millimeters of water (mm H2O) to 120 millimeters of water (mm H2O), or 80 millimeters of water (mm H2O) to 100 millimeters of water (mm H2O). The RTD of the article refers to the difference in static pressure between one or more openings and the mouth end of the article when traversing the interior longitudinal passageway under steady-state conditions with a volumetric flow rate of 17.5 milliliters / second at the mouth end. The RTD of a specimen can be measured using the method described in ISO Standard 6565:2002.

[0106] All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified. The definitions provided herein are intended to facilitate understanding of certain terms used frequently herein.

[0107] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include embodiments having plural referents unless the content clearly dictates otherwise.

[0108] As used in this specification and the appended claims, the term "or" is generally used in its sense including "and / or" unless the context clearly dictates otherwise.

[0109] As used herein, the words "have," "having," "include," "including," "comprise," "comprising," and the like are used in an open-ended sense and generally mean "including, but not limited to." It should be understood that "consisting essentially of," "consisting of," and the like are encompassed by "comprising" and the like.

[0110] The words "preferred" and "preferably" refer to embodiments of the invention that may offer certain advantages, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the present disclosure, including the claims. [Brief explanation of the drawings]

[0111] [Figure 1] FIG. 1 is a schematic cross-sectional view of an aerosol-generating article. [Figure 2] FIG. 2 is a schematic cross-sectional view of another aerosol-generating article. [Figure 3] FIG. 3 is a schematic cross-sectional view of another aerosol-generating article. [Figure 4] FIG. 4 is a schematic cross-sectional view of another aerosol-generating article. [Figure 5] FIG. 5 is a schematic cross-sectional view of an aerosol generation system. [Figure 6] FIG. 6 is a schematic cross-sectional view of an aerosol generation system. DETAILED DESCRIPTION OF THE INVENTION

[0112] The aerosol-generating articles depicted in Figures 1-4 exemplify one or more embodiments of the aerosol-generating articles or components of aerosol-generating articles described above. The schematic drawings are not necessarily to scale and are presented for illustrative purposes, not limitation. The drawings illustrate one or more aspects described in the present disclosure. However, it will be understood that other aspects not depicted in the drawings are within the scope and spirit of the present disclosure.

[0113] The aerosol-generating article 10 of Figure 1 illustrates an aerosol-generating substrate 12 including a tobacco plug, a hollow cellulose acetate tube 14, a polylactic acid filter segment 16, and a mouthpiece segment 18 formed from cellulose acetate material. These four elements are individually wrapped with paper layers. In particular, the aerosol-generating substrate 12 is wrapped with a first paper layer 50 as described herein. These four elements are arranged in end-to-end longitudinal alignment.

[0114] The aerosol-generating substrate 12, hollow cellulose acetate tube 14, and polylactic acid filter segment 16 are bonded together and surrounded by a second paper layer 20 to form an intermediate article. The mouthpiece segment 18 is bonded to the intermediate article by tipping paper 25 to form the aerosol-generating article 10. The first paper layer 50 and second paper layer 20 may cooperate to form a wrapper, as described herein.

[0115] The aerosol-generating article 10 has a mouth end 22 and an upstream distal end 24 located at the opposite end of the article from the mouth end 22. The aerosol-generating article 10 shown in Figure 1 is particularly suitable for use in an electrically operated aerosol-generating device that includes a heater for heating the aerosol-generating substrate 12.

[0116] The aerosol-generating article 100 of Figure 2 comprises four elements arranged in coaxial alignment: a high resistance to withdrawal (RTD) end plug 600 at the distal end 103, a first paper layer 500 surrounding the aerosol-generating substrate 124, a fluid guide 400, and a mouthpiece 170 at the proximal end 101. These four elements are arranged sequentially and surrounded by a second paper layer 110 to form the aerosol-generating article 100. The aerosol-generating article 100 has a proximal or mouth end 101 and a distal end 103 located at the opposite end of the aerosol-generating article 100 from the proximal end 101. The first paper layer 500 and the second paper layer 110 cooperate to form a wrapper, as described herein.

[0117] The aerosol-generating article 100 of Figure 3 illustrates a cutaway view of one example of an aerosol-generating article 100 that is suitable for heating using a blade-like heating element as well as induction heating.

[0118] The aerosol-generating article 100 comprises, in order from proximal to distal, a mouthpiece 170 at the proximal end 101, a fluid guide 400, a recess 700, a first paper layer 500 surrounding the aerosol-generating substrate 124, and an end plug 600. In this embodiment, the aerosol-generating substrate 124 comprises a gel and a susceptor (not shown). The susceptor in this embodiment is a single aluminum strip centrally located along the longitudinal axis of the aerosol-generating substrate 124. The distal end 103 of the aerosol-generating article 100 is inserted into an aerosol-generating device 200 (see FIG. 6), thereby positioning a portion of the aerosol-generating article 100 adjacent to the induction heating element 230 (see FIG. 5) of the aerosol-generating device 200 (see FIG. 6). Electromagnetic radiation generated by the induction heating element 230 is absorbed by the susceptor and assists in heating the aerosol-generating substrate 124 within the first paper layer 500, which in turn assists in the release of material from the aerosol-generating substrate 124, such as the release of nicotine entrained in the passing aerosol, when negative pressure is applied to the proximal end 101 of the aerosol-generating article 100. Fluid, such as air, enters the outer longitudinal passage 831 via an opening (not shown), travels to the cavity 700, and then to the aerosol-generating substrate 124, where it mixes with the aerosol-generating substrate 124 and entrains the nicotine before returning to the cavity, and then exits at the proximal end 101 after passing through an inner longitudinal passage (not shown) in the fluid guide 400.

[0119] In this embodiment, the first paper layer 500 surrounds the aerosol-generating substrate 124, and the first paper layer 500 is surrounded by the second paper layer 110. The first paper layer 500 and the second paper layer 110 form a wrapper, as described herein. The aerosol-generating substrate 124 may include a gel composition.

[0120] The aerosol-generating article 100 illustrated in FIGS. 2 and 3 may be used in conjunction with an aerosol-generating device 200, as illustrated in FIGS.

[0121] The aerosol-generating article 10 of Figure 4 illustrates an aerosol-generating substrate 12, a hollow cellulose acetate tube 14, a hollow tubular segment 16, and a mouthpiece segment 18. The aerosol-generating substrate 12 is wrapped with a first paper layer 50, as described herein. These four elements are arranged end-to-end in longitudinal alignment and surrounded by a second paper layer 20 to form the aerosol-generating article 10. The first paper layer 50 and the second paper layer 20 may cooperate to form a wrapper, as described herein.

[0122] The aerosol-generating article 10 has a mouth end 22 and an upstream distal end 24 located at the opposite end of the article from the mouth end 22. The aerosol-generating article 10 shown in Figure 4 is particularly suitable for use in an electrically operated aerosol generating device that includes a heater for heating the aerosol-generating substrate 12.

[0123] The aerosol-generating substrate 12 has a length of approximately 12 millimeters and a diameter of approximately 7 millimeters. The aerosol-generating substrate 12 is cylindrical in shape and has a substantially circular cross-section. The aerosol-generating substrate 12 comprises an assembly of a sheet of homogenized tobacco material. The sheet of homogenized tobacco material contains 10 weight percent glycerin on a dry basis. The hollow cellulose acetate tube 14 has a length of approximately 8 millimeters and a thickness of 1 millimeter. The mouthpiece segment 18 comprises a plug of cellulose acetate tow with 8 denier per filament and has a length of approximately 7 millimeters.

[0124] The hollow tubular segment 14 is provided as a cylindrical tube having a length of approximately 18 millimeters and a wall thickness of approximately 100 micrometers. The aerosol-generating article 10 includes a ventilation zone 26 provided approximately 5 millimeters from the upstream end of the mouthpiece segment 18. The ventilation zone 26 is therefore approximately 12 millimeters from the downstream end of the aerosol-generating article and approximately 13 millimeters from the upstream end of the hollow tubular segment. The ventilation zone 26 is therefore approximately 21 millimeters from the downstream end of the aerosol-generating substrate 12.

[0125] 5-6 illustrate examples of an aerosol-generating article 100 and an aerosol-generating device 200. The aerosol-generating article 100 has a proximal or mouth end 101 and a distal end 103. In FIG. 5, the distal end 103 of the aerosol-generating article 100 is received within a container 220 of the aerosol-generating device 200. The aerosol-generating device 200 includes a housing 210 defining the container 220 configured to receive the aerosol-generating article 100. The aerosol-generating device 200 also includes a heating element 230 forming a recess 235 configured to receive the aerosol-generating article 100, preferably by an interference fit. The heating element 230 may comprise an electrical resistance heating component. Additionally, the device 200 includes a power source 240 and control electronics 250 that cooperate to control the heating of the heating element 230.

[0126] The heating element 230 may heat the distal end 103 of the aerosol-generating article 100. In this embodiment, the aerosol-generating substrate 124 comprises a gel containing nicotine. Heating the aerosol-generating article 100 causes the aerosol-generating substrate 124 to produce an aerosol containing nicotine, which can travel and exit the aerosol-generating article 100 at the proximal end 101. The aerosol-generating device 200 comprises a housing 210. Figures 5-6 do not show the exact heating mechanism.

[0127] In some embodiments, the heating mechanism may be by conductive heating, where heat is transferred from the heating element 230 of the aerosol-generating device 200 to the aerosol-generating article 100. This is easily achieved when the aerosol-generating article 100 is positioned within the container 220 of the aerosol-generating device 200 and the distal end 103 (preferably the end where the aerosol-generating substrate 124 is located) and therefore the aerosol-generating article 100 is in contact with the heating element 230 of the aerosol-generating device 200. In particular embodiments, the heating element comprises a heating blade that protrudes from the aerosol-generating device 200 and is suitable for penetrating into the aerosol-generating article 100 to directly contact the aerosol-generating substrate 124.

[0128] In this embodiment, the heating mechanism is by induction, whereby a heating element emits radio-magnetic radiation that is absorbed by the tubular element when the aerosol-generating article 100 is positioned within the container 220 of the aerosol-generating device 200 .

[0129] When the aerosol-generating article 100 is releasably received within the aerosol-generating device 200 and on the heating element 230, the aerosol-generating device 200 is activated, heating the aerosol-generating substrate 124 to a temperature of approximately 375 degrees Celsius. When a user draws on the mouth end 101 of the aerosol-generating article 100, volatile compounds released from the aerosol-generating substrate 124 are drawn downstream through the aerosol-generating article 100 and condense to form an aerosol that is drawn through the mouthpiece 101 of the aerosol-generating article 100 and into the user's mouth. The wrapper 500, 110 repels aerosol-forming agents and moisture from the aerosol, reducing contamination and weakening of the wrapper 500, 110.

[0130] The first paper layer 50, 500 includes a paper layer having a thickness / basis weight of about 1.2 micrometers / gsm or less. The first paper layer 50, 500 preferably has a thickness / basis weight within the range of about 1.0 micrometers / gsm to about 1.2 micrometers / gsm. The first paper layer 50, 500 may have a thickness of less than about 50 micrometers, or less than about 40 micrometers. The first paper layer 50, 500 may have a basis weight within the range of about 25 gsm to about 45 gsm, or about 35 gsm to about 40 gsm.

[0131] The first paper layer 50, 500 preferably has a thickness / basis weight of about 1.2 micrometers / gsm or less and a water contact angle of at least about 30 degrees. The first paper layer 50, 500 may also have a water contact angle of at least about 40 degrees, or at least about 45 degrees.

[0132] The first paper layer 50, 500 preferably has a caliper / basis weight of about 1.2 micrometers / gsm or less and a CD / MD elongation to break ratio of about 2.5 or less. The first paper layer 50, 500 may have a CD / MD elongation to break ratio of about 2.2 or less, or about 2 or less.

[0133] Preferably, the first paper layer 50, 500 has a thickness / basis weight of about 1.2 micrometers / gsm or less and preferably has a negative result to at least one kit oil sample of Method Tappi 559cm-02 Classical Method 2002. The first paper layer 50, 500 may have a negative result to at least five kit oil samples, or all ten kit oil samples of Method Tappi 559cm-02 Classical Method 2002.

[0134] The wrapper includes a first paper layer 50, 500 and a second paper layer 20, 110, the first paper layer 50, 500 having a first thickness / basis weight value and the second paper layer 20, 110 having a second thickness / basis weight value, the first thickness / basis weight value being preferably less than the second thickness / basis weight value. The first thickness / basis weight value may be less than 1.2 micrometers / gsm, and the wrapper may have a total thickness of less than about 80 micrometers.

[0135] The first paper layer 50, 500 preferably comprises PVOH (polyvinyl alcohol) or silicone. The first paper layer 50, 500 may also comprise a surface treatment comprising PVOH or silicone. The addition of PVOH (polyvinyl alcohol) or silicone may improve the grease barrier properties of the wrapper.

[0136] The second paper layer 20, 110 preferably comprises PVOH (polyvinyl alcohol) or silicone. The second paper layer 20, 110 may also comprise a surface treatment comprising PVOH or silicone. The addition of PVOH (polyvinyl alcohol) or silicone may improve the grease barrier properties of the wrapper.

[0137] The exemplary embodiments described above are not limiting, and other embodiments consistent with the exemplary embodiments described above will be apparent to those skilled in the art.

[0138] The present specification describes at least the following items. (1) An aerosol-generating article, an aerosol-generating substrate comprising nicotine and at least about 10% of an aerosol former comprising glycerin; a wrapper disposed around and in contact with the aerosol-generating substrate, the wrapper comprising a paper layer having a thickness / basis weight of about 1.2 micrometers / gsm or less. (2) The aerosol-generating article according to (1) above, wherein the paper layer has a thickness / basis weight within the range of about 1.0 micrometers / gsm to about 1.2 micrometers / gsm. (3) An aerosol-generating article according to any one of (1) to (2) above, wherein the paper layer has a thickness of less than about 50 micrometers or less than about 40 micrometers. (4) The aerosol-generating article according to any one of (1) to (3) above, wherein the paper layer has a basis weight within the range of about 25 gsm to about 45 gsm, or about 35 gsm to about 40 gsm. (5) The aerosol-generating article according to any one of (1) to (4) above, wherein the paper layer contains PVOH or silicone. (6) The aerosol-generating article according to any one of (1) to (5) above, wherein the paper layer is surface-treated with PVOH or silicone. (7) The aerosol-generating article according to any one of (1) to (6) above, wherein the paper layer contains PVOH. (8) The aerosol-generating article according to any one of (1) to (7) above, wherein the paper layer contains silicon. (9) The aerosol-generating article according to any one of (1) to (8) above, wherein the aerosol-generating substrate contains a gel composition. (10) An aerosol-generating article according to (9) above, wherein the gel composition contains a large amount of glycerin. (11) The aerosol-generating article according to (10) above, wherein the gel composition contains xanthan gum. (12) The aerosol-generating article according to any one of (1) to (11) above, wherein the aerosol-generating substrate contains homogenized tobacco material. (13) The aerosol-generating article described in (12) above, wherein the homogenized tobacco material comprises, on a dry weight basis, tobacco material, about 1 percent to about 5 percent binder, and about 5 percent to about 30 percent aerosol former. (14) The aerosol-generating article according to any one of (1) to (13) above, wherein the aerosol-generating substrate comprises a metal induction heating element. (15) The aerosol-generating article according to any one of (1) to (14) above, wherein the aerosol-generating substrate comprises a plurality of metal induction heating elements.

Claims

1. An aerosol-generating article, comprising: an aerosol-generating substrate comprising nicotine and at least about 10% of an aerosol former comprising glycerin; a wrapper disposed around and in contact with the aerosol-generating substrate, the wrapper comprising a paper layer having a thickness / basis weight of about 1.2 micrometers / gsm or less.

2. 2. The aerosol-generating article of claim 1, wherein the paper layer has a thickness / basis weight in the range of about 1.0 micrometers / gsm to about 1.2 micrometers / gsm.

3. 3. The aerosol-generating article according to claim 1, wherein the paper layer has a thickness of less than about 50 micrometers, or less than about 40 micrometers.

4. 4. The aerosol-generating article according to claim 1, wherein the paper layer has a basis weight in the range of about 25 gsm to about 45 gsm, or about 35 gsm to about 40 gsm.

5. 5. The aerosol-generating article according to claim 1, wherein the paper layer comprises PVOH or silicone.

6. 6. The aerosol-generating article according to claim 1, wherein the paper layer comprises a surface treatment comprising PVOH or silicone.

7. The aerosol-generating article according to any one of claims 1 to 6, wherein the paper layer comprises PVOH.

8. 8. The aerosol-generating article according to claim 1, wherein the paper layer contains silicone.

9. 9. The aerosol-generating article according to claim 1, wherein the aerosol-generating substrate comprises a gel composition.

10. 10. The aerosol-generating article of claim 9, wherein the gel composition comprises a large amount of glycerin.

11. 11. The aerosol-generating article of claim 10, wherein the gel composition comprises xanthan gum.

12. 12. The aerosol-generating article of claim 1, wherein the aerosol-generating substrate comprises homogenized tobacco material.

13. 13. The aerosol-generating article of claim 12, wherein the homogenized tobacco material comprises, on a dry weight basis, tobacco material, from about 1 percent to about 5 percent binder, and from about 5 percent to about 30 percent aerosol former.

14. 14. The aerosol-generating article according to claim 1, wherein the aerosol-generating substrate comprises a metal induction heating element.

15. 15. The aerosol-generating article according to claim 1, wherein the aerosol-generating substrate comprises a plurality of metal induction heating elements.

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