ES2974807T3 - Stable packaging for aerosol generating article - Google Patents

Abstract

An aerosol-generating article (10) includes an aerosol-generating substrate (12) comprising nicotine and a wrapper (50) disposed around the aerosol-generating substrate. The wrapper includes a paper layer having a thickness/gram of about 1.2 micrometers/gsm or less. (Automatic translation with Google Translate, no legal value)

Description

DESCRIPTION

Stable packaging for aerosol-generating articles

The present disclosure relates to a wrapper used in aerosol-generating articles, wherein the wrapper has a paper density and can be used with an aerosol-generating substrate.

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

The paper used to wrap the aerosol-generating substrate may absorb aerosol former, water, and other liquid compounds found in mainstream smoke or aerosol passing through the aerosol-generating article, or moisture surrounding the paper. The absorbed liquid may 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 tearing due to the high levels of aerosol former in the aerosol-generating substrate of these heated aerosol-generating articles. Heated aerosol-generating articles are particularly susceptible to swelling as aerosol components are absorbed by the wrap, leading to difficult removal from the heating device. Heated aerosol-generating articles are particularly susceptible to tearing when tightly received and then removed from a heating device.

EP 3086669 A1 describes an aerosol-generating article comprising an aerosol-generating substrate comprising nicotine and at least about 10% aerosol former comprising glycerin; and a wrapper disposed around and in contact with the aerosol-generating substrate, wherein the wrapper comprises a paper layer having a thickness/grammage of about 1.2 microns/g/m2 or less, and wherein the paper layer comprises a surface treatment.

It would be desirable to provide a visually and mechanically stable wrapped aerosol-generating substrate, particularly for aerosol-generating articles containing a high level of liquids or aerosol formers.

It would be desirable to provide an aerosol-generating article that includes an envelope that does not swell by absorption of water or compounds contained in the aerosol-generating substrate.

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

It would also be desirable if this wrapper did not affect the taste of the aerosol generated by the aerosol-generating article.

It would also be convenient if this wrap does not burn easily if it is near a heating element.

The purpose of the invention may be to at least partially solve one or more of the above-mentioned desirable technical benefits.

Accordingly, there is provided an aerosol-generating article comprising an aerosol-generating substrate comprising nicotine, and a wrapper disposed around the aerosol-generating substrate. The wrapper comprises a paper layer having a thickness/grammage of about 1.2 microns/g/mf or less. In accordance with the invention, there is provided an aerosol-generating article comprising an aerosol-generating substrate comprising nicotine and at least about 10% aerosol former comprising glycerin and a wrapper disposed around and in contact with the aerosol-generating substrate. The wrapper comprises a paper layer having a thickness/grammage of about 1.2 microns/g/mf or less.

Preferably, the paper layer has a thickness/grammage in a range of about 1.0 micrometers/g/m2 to about 1.2 micrometers/g/mP. 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 grammage in a range of about 25 g/m2 to about 45 g/m2, or about 35 g/mf to about 40 g/mf.

Preferably, the paper layer has a thickness/grammage of about 1.2 micrometers/g/mf 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.

The term “MD” refers to a machine direction of the wrapper. The machine direction is the direction in which the paper stock flows into and through a papermaking machine. The machine direction is the circumferential direction of a roll of paper as it is wound off the paper machine. The machine direction may also be referred to as the grain direction.

The term “CD” refers to a transverse direction of the wrap. The transverse wrap direction is an in-plane direction of the wrap. The transverse wrap direction is orthogonal to the machine direction of the wrap.

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 paper layer may have a CD/MD elongation at break ratio in a range of about 1.8 to 2.2.

Preferably, the wrapper comprises a paper layer having a thickness/grammage of about 1.2 microns/g/m2 or less and a negative result for at least one oil sample from the Tappi Method 559 cm-02 Classic Method 2002 kit. The paper layer may have a negative result for at least five oil samples from the kit, or all ten oil samples from the Tappi Method 559 cm-02 Classic Method 2002 kit.

Preferably, the wrapper includes two layers of paper wherein a first layer of paper has a first thickness/grammage value and the second layer of paper has a second thickness/grammage value and the first thickness/grammage value is less than the second thickness/grammage value. The first thickness/grammage value may be less than 1.2 microns/g/mP and the wrapper may have a total thickness of less than about 80 microns.

The paper layer comprises a surface treatment comprising PVOH or silicon. The addition of PVOH (polyvinyl alcohol) or silicon may improve the grease barrier properties of the wrapper.

The term “silicon” refers to siloxane. Silicon or siloxane preferably comprises a polydimethylsiloxane.

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

Preferably, the aerosol-generating substrate may comprise a gel composition. The gel composition may comprise a majority (by weight) of glycerin. The gel composition may comprise xanthan gum.

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.

The wrapper may be made of a single layer of paper. The wrapper may be made of two layers of paper. The wrapper may be made of more than two layers of paper.

Preferably, the envelope covers at least 20%, at least 50%, at least 80%, at least 90%, at least 95%, at least 99% or preferably around the entire length (the full length) of the aerosol-generating substrate. The envelope preferably covers the entire aerosol-generating substrate and does not extend beyond the aerosol-generating substrate.

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

When the wrapper has two or more layers of paper, a first layer of paper may possess the unique properties described herein and a second layer of paper may also possess the unique properties described herein. All of the layers of paper forming the wrapper may possess the unique properties described herein. In particular, one or both of the layers of paper forming the wrapper comprise a surface treatment comprising PVOH or silicon.

Advantageously, aerosol-generating articles including a wrapper described herein can reduce wetting and absorption of water, aerosol formers, or grease in 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 can be reduced even when a high level of aerosol former is included in the aerosol-generating substrate.

Advantageously, the aerosol-generating article provides a visually and mechanically stable wrapped aerosol-generating substrate that prevents swelling. This is particularly useful for heated, but not burning aerosol-generating articles that can be inserted into the heating device. The wrap of the aerosol-generating article resists burning if it is close to a heating element, therefore inductive heating elements can be incorporated along the aerosol-generating substrate.

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

A conventional cigarette is lit when a user applies a flame to one end of the cigarette and draws air through the other end. The localized heat provided by the flame and oxygen in the air drawn through the cigarette causes the end of the cigarette to ignite, and the resulting combustion generates inhalable smoke. In contrast, in heated aerosol-generating articles, an aerosol is generated by heating a flavor-generating substrate, such as tobacco. Known heated aerosol-generating articles include, for example, electrically heated aerosol-generating articles and aerosol-generating articles in which an aerosol is generated by heat transfer from a combustible fuel element or heat source to a physically separate aerosol-forming substrate. For example, aerosol-generating articles according to the disclosure find particular application in aerosol-generating systems comprising an electrically heated aerosol-generating device having an internal heating sheet that is adapted to be inserted into the rod of the aerosol-generating substrate. Aerosol-generating articles of this type are described in the prior art, for example in EP 0822670.

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

As used herein, the term “aerosol-generating system” refers to a combination of an aerosol-generating device and an aerosol-generating article.

The term “aerosol-generating substrate” refers to a substance capable of generating or releasing an aerosol. The aerosol-generating substrate may be a solid, paste, gel, suspension, liquid, or comprise any combination of solid, paste, gel, suspension, and liquid compositions. Preferably the aerosol-generating substrate is a solid, or a gel composition. The aerosol-generating substrate may preferably include nicotine.

The aerosol-generating article may comprise an aerosol-generating substrate and a nozzle. The nozzle may comprise a filter. A tip wrap may attach the filter to the aerosol-generating substrate.

An aerosol-generating substrate may be a solid composition. This composition may include plant-derived material. The aerosol-generating substrate may include tobacco, and preferably the tobacco contains volatile tobacco flavoring compounds, which are released from the aerosol-generating substrate upon heating. The aerosol-generating substrate may comprise homogenized tobacco material, an aerosol former, and a binder.

Nicotine may be present in the aerosol-generating substrate in a 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 may include 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.

The aerosol-generating substrate may include a flavorant. Botanical materials provide a flavorant that can impart a flavor to the taste of the aerosol generated by the aerosol-generating article. A flavorant is any natural or artificial compound that affects the organoleptic quality of the aerosol. Non-limiting examples of flavorant sources include mints, such as peppermint and spearmint, coffee, tea, cinnamon, clove, cocoa, vanilla, eucalyptus, geranium, agave, and juniper, and combinations thereof.

The aerosol-generating substrate may include an essential oil. Essential oils may provide a flavorant that can impart a flavor to the flavor 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%.

An aerosol-generating substrate may include a gel composition. The term “gel” refers to a solid at room temperature. “Solid” in this context means that the gel has a stable size and shape and does not flow. Room temperature in this context means 25 degrees Celsius. A gel can be defined as an essentially dilute, cross-linked system, which does not exhibit flow when in a steady state. By weight, gels may be mostly liquid, but they behave like solids due to a cross-linked three-dimensional network within the liquid. It is the cross-linking within the fluid that gives a gel its structure (hardness). Thus, gels may be a dispersion of molecules of a liquid within a solid where the liquid particles are dispersed in the solid medium.

The gel composition may include a solid-forming gelling agent, 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 solid-forming gelling agents, 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 viscosifying agent, and a solid-forming gelling agent, glycerin dispersed in the solid medium, and nicotine dispersed in the glycerin. The composition forms a stable gel phase. A gel composition may include nicotine, an aerosol former, a viscosifying agent, a hydrogen-bonded cross-linking gelling agent, and an ionic cross-linking gelling agent. The gel composition may further include divalent cations.

The term “viscosity agent” refers to a compound which, when homogeneously added into a 25°C, 50% by weight water/50% by weight glycerin mixture, in an amount of 0.3% by weight, increases the viscosity without leading to the formation of a gel, the mixture remaining or remaining fluid. Preferably, the viscosifying agent refers to a compound which when homogeneously added into a 25°C 50% by weight water/50% by weight glycerin mixture, in an amount of 0.3% by weight, increases the viscosity to at least 50 cP, preferably at least 200 cP, preferably at least 500 cP, preferably at least 1000 cP at a shear rate of 0.1 s-1, without leading to the formation of a gel, the mixture remaining or remaining fluid. Preferably, the viscosifying agent refers to a compound which when homogeneously added into a 25 °C 50% by weight water/50% by weight glycerin mixture, in an amount of 0.3% by weight, increases the viscosity at least 2 times, or at least 5 times, or at least 10 times, or at least 100 times higher than before the addition, at a shear rate of 0.1 s-1, without leading to the formation of a gel, the mixture remaining or remaining fluid.

The viscosity values cited in this description can be measured by using the Brookfield RVT viscometer rotating a RV#2 disk type spindle at 25 °C at a speed of 6 revolutions per minute (rpm).

The term “gelling agent” refers to a compound that homogeneously, when added to a 50% by weight water/50% by weight glycerin mixture, in an amount of about 0.3% by weight, forms a solid medium or support matrix leading to a gel. Gelling agents include, but are not limited to, hydrogen-bonded cross-linking gelling agents, and ionic cross-linking gelling agents.

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

The term “ionic cross-linking gelling agent” refers to a gelling agent that forms non-covalent cross-links or physical cross-links through ionic bonding. Ionic cross-linking involves the association of polymer chains by non-covalent interactions. A cross-linked network is formed when oppositely charged multivalent molecules are electrostatically attracted to each other, resulting in a cross-linked polymer network.

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

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

The gel composition preferably comprises no water or a low level of water. When the gel composition comprises no water or a low level of water, the gel composition may comprise a higher level of other compounds such as aerosol former, gelling agent, viscosifying agent and nicotine. In addition, gel compositions that comprise no water or a low level of water are easier and require less energy to vaporize. Aerosols formed from a gel composition that comprises no water or a low level of water may be perceived as less hot by the user. Preferably, the gel composition comprises less than about 40% by weight, preferably less than about 30% by weight, preferably less than about 25% by weight of water. The gel composition may comprise less than about 20% by weight or less than about 15% by weight or less than about 10% by weight or less than about 5% by weight of water. The gel composition may preferably comprise some water. The gel composition is more stable when the composition comprises some water. Preferably, the gel composition comprises at least about 1% by weight, or at least about 2% by weight, or at least about 5% by weight of water. Preferably, the gel composition comprises at least about 10% by weight, or at least about 15% by weight of water. Preferably, the gel composition comprises a range of about 15% by weight to about 25% by weight of water.

The gel composition may include gelling agents which are the hydrogen bonded cross-linking gelling agent and the ionic cross-linking gelling agent. The gel composition may further include a viscosifying agent. The gelling agents may form a solid medium in which the aerosol former may be dispersed. The gelling agents may form a solid medium in which the aerosol former and water may be dispersed. The viscosifying agent combined with the hydrogen bonded cross-linking gelling agent and the ionic cross-linking gelling agent appears to surprisingly support the solid medium and maintain the gel composition even when the gel composition comprises a high level of glycerin.

The gel composition may include the gelling agents in a range of about 0.4% to about 10% by weight. Preferably, the composition may include the gelling agents in a range of about 0.5% to about 8% by weight. Preferably, the composition may include the gelling agents in a range of about 1% to about 6% by weight. Preferably, the composition may include the gelling agents in a range of about 2% to about 4% by weight. Preferably, the composition may include the gelling agents in a range of about 2% to about 3% by weight.

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

The gel composition may include the viscosifying agent, the hydrogen-bonded cross-linking gelling agent, and the ionic cross-linking gelling agent that are present in the gel composition in a total amount of about 1% by weight to about 8% by weight. Preferably, the gel composition may include the viscosifying agent, the hydrogen-bonded cross-linking gelling agent, and the ionic cross-linking gelling agent that are present in the gel composition in a total amount of about 2% by weight to about 6% by weight. Preferably, the gel composition may include the viscosifying agent, the hydrogen-bonded cross-linking gelling agent, and the ionic cross-linking gelling agent that are present in the gel composition in a total amount of about 3% by weight to about 5% by weight.

The gel composition may include the viscosifying agent, the hydrogen-bonded cross-linking gelling agent, and the ionic cross-linking gelling agent, each independently present in the gel composition in a range of from about 0.3% by weight to about 3% by weight. Preferably, the gel composition may include the viscosifying agent, the hydrogen-bonded cross-linking gelling agent, and the ionic cross-linking gelling agent, each independently present in the gel composition in a range of from about 0.5% by weight to about 2% by weight. Preferably, the gel composition may include the viscosifying agent, the hydrogen-bonded cross-linking gelling agent, and the ionic cross-linking gelling agent, each independently present in the gel composition in a range of from about 1% by weight to about 2% by weight.

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

The gel composition may include a viscosifying agent such as xanthan gum in a range of about 0.2% to about 5% by weight. Preferably the xanthan gum may be in a range of about 0.5% to about 3% by weight. Preferably the xanthan gum may be in a range of about 0.5% to about 2% by weight. Preferably the xanthan gum may be in a range of about 1% to about 2% by weight.

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

The gel composition may include the hydrogen-bonded cross-linking gelling agent such as agar in a range of about 0.3% to about 5% by weight. Preferably, the composition may include the hydrogen-bonded cross-linking gelling agent in a range of about 0.5% to about 3% by weight. Preferably, the composition may include the hydrogen-bonded cross-linking gelling agent in a range of about 1% to about 2% by weight.

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

The gel composition may include the ionic cross-linking gelling agent such as low acyl gellan in a range of about 0.3% to about 5% by weight. Preferably, the composition may include the ionic cross-linking gelling agent in a range of about 0.5% to about 3% by weight. Preferably, the composition may include the ionic cross-linking gelling agent in a range of about 1% to about 2% by weight.

The gel composition may further include a divalent cation. Preferably, the divalent cation may include calcium ions, such as calcium lactate in solution. Divalent cations (such as calcium ions) may aid in the gel formation of compositions that include gelling agents such as the ionic cross-linking gelling agent, for example. The ionic effect may aid in gel formation. The divalent cation may be present in the gel composition in a range of about 0.1 to about 1% by weight, or about 0.5% by weight.

The gel composition may further include an acid. The acid may comprise a carboxylic acid. The carboxylic acid may include a ketone group. Preferably, the carboxylic acid may include a ketone group having 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, this carboxylic acid has three carbon atoms (such as lactic acid). Lactic acid surprisingly improves the stability of the gel composition even over similar carboxylic acids. The carboxylic acid may aid in gel formation. The carboxylic acid may reduce the variation in nicotine concentration within the gel composition during storage.

The gel composition may include a carboxylic acid such as lactic acid in a range of about 0.1% to about 5% by weight. Preferably the carboxylic acid may be in a range of about 0.5% to about 3% by weight. Preferably the carboxylic acid may be in a range of about 0.5% to about 2% by weight. Preferably the carboxylic acid may be in a range of about 1% to about 2% by weight.

Nicotine is included in the gel compositions. Nicotine may be added to the composition in free base form or in salt form. The gel composition may include about 0.5 to about 10% by weight, nicotine, or about 0.5 to about 5% by weight, nicotine. Preferably, the gel composition may include 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 aspects, water may be the most volatile component of the gel formulation and the nicotine component of the gel formulation may be the second most volatile component of the gel formulation.

An 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 air flow path extending between the at least one air inlet and the mouth-side end of the article. The heat source is preferably located upstream of the aerosol-generating substrate. The heat source may be integral with an aerosol-generating device and a consumable aerosol-generating article may be releasably received within the aerosol-generating device.

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 in the form of a sheet that can be inserted into the aerosol-generating substrate. Alternatively, the heat source may be configured to surround the aerosol-generating substrate, and as such may be in the form of a hollow cylinder, or any other suitable shape. Alternatively, the heat source is a combustible heat source. As used herein, a combustible heat source is a heat source that is itself burned to generate heat during use, which, unlike a cigarette, tobacco, or cigar, does not involve combustion of the aerosol-generating substrate. A combustible heat source may comprise carbon and an ignition aid, such as a metal peroxide, superoxide, or nitrate, wherein the metal is an alkali or alkaline earth metal.

The aerosol-generating substrate may include an induction heating element or susceptor or a plurality of induction heating elements or susceptors. The induction heating elements or susceptors are heated in the presence of an alternating or fluctuating electromagnetic field. When heating is by induction heating, a fluctuating electromagnetic field is transmitted through the aerosol-generating article to the induction heating element or susceptor such that the susceptor or inductive heating element changes the fluctuating field to thermal energy thereby heating the aerosol-generating substrate.

The induction heating element or susceptor may be formed from any material that can be heated by induction to a temperature sufficient to generate an aerosol from the aerosol generating substrate. The induction heating element or susceptor may comprise a metal or carbon. A preferred inductive heating element or susceptor may comprise a ferromagnetic material, for example ferritic iron, or a ferromagnetic steel or stainless steel. The induction heating element or susceptor may comprise aluminum. The inductive heating element or susceptors may be formed from 400 series stainless steels, for example 410 grade, or 420 grade, or 430 grade stainless steel. Different materials will dissipate different amounts of energy when placed within electromagnetic fields having similar values of frequency and field strength. Preferably, the induction heating element or susceptors are heated to a temperature greater than 250 degrees Celsius. However, preferably the induction heating element or susceptors are heated less than 350 degrees Celsius to avoid burning of the material in contact with the susceptor.

The induction heating element or susceptor may be located close to the envelope of the aerosol generating substrate since the envelope described herein advantageously resists combustion.

As used herein, the term “mouthpiece” refers to the portion of the aerosol-generating article designed to come into contact with the mouth of the consumer. The mouthpiece may be the portion of the aerosol-generating article that may include a filter or, in some cases, the mouthpiece may be defined by the extension of the tip wrap. In other cases, the mouthpiece may be defined as a portion of the aerosol-generating article that extends approximately 40 mm from the mouth-side end of the aerosol-generating article or that extends approximately 30 mm from the mouth-side end of the aerosol-generating article.

The terms “upstream” and “downstream” refer to the relative positions of the elements of the aerosol-generating article described in relation to the direction of the aerosol as it is drawn from an aerosol-generating substrate and through the nozzle.

The term “wrap” or “paper wrap” is interchangeable and refers to one or more layers of wrapping material that circumscribes an aerosol-generating substrate to contain the aerosol-generating substrate or maintain the shape of the aerosol-generating article and is formed of paper. The wrap mitigates staining on the external surface of the aerosol-generating article. Preferably the wrap comes into contact with the aerosol-generating substrate.

The term “hydrophobic” refers to a surface that exhibits water-repellent properties. A useful way to determine this is to measure the water contact angle. The “water contact angle” is the angle, conventionally measured across the liquid, where a liquid/vapor interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid through Young’s equation.

A wrapper used in aerosol-generating articles is described, wherein the wrapper comprises a paper layer having a high density and usable with an aerosol-generating substrate. Further described is an aerosol-generating article comprising an aerosol-generating substrate comprising nicotine, and a wrapper disposed around the aerosol-generating substrate. The wrapper includes a paper layer having a thickness/grammage of about 1.2 microns/g/m2 or less.

Preferably, the wrapper comprises a paper layer having a thickness/grammage in a range of about 0.8 microns/g/mf to about 1.2 microns/g/mf. The paper layer may have a thickness/grammage in a range of about 1.0 microns/g/mf to about 1.2 microns/g/m2. The paper layer may have a thickness/grammage of about 1.0 microns/g/mf. The paper layer may have a thickness/grammage of about 0.9 microns/g/mP. The paper layer may have a thickness/grammage of about 1.0 microns/g/mP. The paper layer may have a thickness/grammage of about 1.1 microns/g/mP. The paper layer may have a thickness/grammage of about 1.2 microns/g/mP.

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 a range of about 10 micrometers to about 50 micrometers. The paper layer may have a thickness in a range of about 20 micrometers to about 50 micrometers. The paper layer may have a thickness in a range of about 30 micrometers to about 50 micrometers. The paper layer may have a thickness in a range of about 35 micrometers to about 50 micrometers. The paper layer may have a thickness in a range of about 35 micrometers to about 40 micrometers. The paper layer may have a thickness in a range of about 40 micrometers to about 50 micrometers.

The paper layer may have a grammage in a range of about 25 g/m2 to about 45 g/m2. The paper layer may have a grammage in a range of about 30 g/m2 to about 45 g/m2. The paper layer may have a grammage in a range of about 35 g/m2 to about 45 g/m2. The paper layer may have a grammage in a range of about 35 g/m2 to about 40 g/m2.

In one embodiment, a paper layer has a basis weight of about 35 g/mP and a thickness of about 37 microns. This paper layer has a thickness/basis weight value of about 1.06.

Preferably, the paper layer comprises PVOH (polyvinyl alcohol) or silicon. In one embodiment the paper layer includes 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 and form a layer on the outer 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. The PVOH may be disposed on and form a layer on the inner surface of the paper layer of the aerosol-generating article. The PVOH may be disposed on the inner surface and the outer surface of the paper layer of the aerosol-generating article. The PVOH may be disposed on and form a layer on the inner surface and the outer surface of the paper layer of the aerosol-generating article.

The paper layer comprises a surface treatment comprising PVOH or silicon. The paper layer may comprise a surface treatment comprising PVOH. The paper layer may comprise a surface treatment comprising silicon. This surface treatment may be applied to the outer surface of the paper layer. This surface treatment may be applied to the inner surface of the paper layer. This surface treatment may be applied to both the outer and inner surface of the paper layer. The addition of PVOH or silicon may improve the grease barrier properties of the paper layer.

The aerosol-generating substrate may include a gel composition. The gel composition may comprise a majority of the aerosol former such as glycerin. The gel composition may include nicotine, at least about 50% by weight of glycerin or at least 70% by weight of glycerin, at least about 0.2% by weight of hydrogen-bonded cross-linking gelling agent, at least about 0.2% by weight of ionic cross-linking gelling agent, and at least about 0.2% by weight of viscosifying agent. The gel composition may comprise xanthan gum.

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

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.

It is contemplated that the wrapper described herein may reduce and prevent the formation of stains on an aerosol-generating article that are visible to a consumer. It has been observed that stains may appear on an aerosol-generating article after storage in a humid environment or during consumption. The stains may be due to the absorption of water or aerosol former, including any suspended or dissolved colored substance, into the network of cellulose fibers that make up the wrapper. Without being bound by theory, the water or aerosol former interacts with the cellulosic fibers of the paper and alters the organization of the fibers resulting in a local change in the optical properties, such as brightness, color and opacity, and mechanical properties, such as tensile strength, permeability of the wrapper.

It is contemplated that the wrap described herein may reduce and prevent swelling of the aerosol-generating article. Reducing or preventing swelling of the aerosol-generating article improves the ease of use of the aerosol-generating article to safely insert and remove the aerosol-generating article from a heating device without damaging the aerosol-generating article.

The wrapper is the 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 aerosol-generating substrate plug. Preferably the wrapper contains the aerosol-generating substrate over at least about 90% of the length of the aerosol-generating substrate plug. More preferably, the wrapper contains the aerosol-generating substrate over at least about 100% of the length of the aerosol-generating substrate plug.

This wrapper may exhibit a range of permeability including no permeability. The permeability of the cigarette paper is determined using the international standard test method ISO 2965:2009 and the result is presented as cubic centimeters per minute per square centimeter and is referred to as “CORESTA units.” The permeability of the wrapper described herein may be in a range of about 1 to about 10 CORESTA units, about 5 to about 20 CORESTA units, or about 1 to about 5 CORESTA units.

The wrapper may be formed from any cellulosic material such as paper, wood, cloth, natural as well as man-made fibers. Preferably the wrapper does not include fillers, such as calcium carbonate. Preferably the wrapper is formed from at least 90% by weight of cellulosic material. Preferably the wrapper is formed from at least 95% by weight of cellulosic material.

The paper layer may be formed from any cellulosic material such as paper, wood, cloth, natural as well as man-made fibers. Preferably the paper layer does not include 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.

The surface of the paper layer may have a water contact angle of at least about 30 degrees, at least about 35 degrees, at least about 40 degrees, or at least about 45 degrees. Hydrophobicity or water contact angle is determined using the TAPPI T558 test and the result is presented as an interfacial contact angle and is reported in “degrees” and can range from near zero degrees to near 180 degrees.

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 a 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, orthogonal to the machine direction of the paper layer.

The paper layer may have a negative result (no visible stains) for at least one oil sample from the Tappi Method 559 cm-02 Classic Method 2002 kit. The paper layer may have a negative result for at least five oil samples from the kit, or all ten oil samples from the Tappi Method 559 cm-02 Classic Method 2002 kit.

The wrapper may include two layers of paper, wherein the first layer of paper has a first thickness/grammage value and the second layer of paper has a second thickness/grammage value and the first thickness/grammage value is less than the second thickness/grammage value. The first thickness/grammage value is less than 1.2 micrometers/g/m2 and the wrapper has a total thickness of less than about 80 micrometers.

The wrapper may include two layers of paper wherein the first layer contacts the aerosol-forming substrate and the second layer covers the first layer and forms an exterior surface of the aerosol-forming article. The first layer may have a first thickness/grammage value of less than 1.2 micrometers/g/m2 and the second layer may have a second thickness/grammage value of greater than 1.2 micrometers/g/mf.

The wrapper may include two layers of paper wherein the first layer contacts the aerosol-forming substrate and the second layer covers the first layer and forms an exterior surface of the aerosol-forming article. The first layer may have a first thickness/grammage value of less than 1.2 micrometers/g/mf and the second layer may have a second thickness/grammage value of less than 1.2 micrometers/g/mf.

The wrapper may include two layers of paper wherein the first layer contacts the aerosol-forming substrate and the second layer covers the first layer. The first layer may comprise PVOH (polyvinyl alcohol) or silicon or comprise a surface treatment comprising PVOH or silicon. The second layer may comprise PVOH (polyvinyl alcohol) or silicon or comprise a surface treatment comprising PVOH or silicon. Both the first and second layers may comprise PVOH (polyvinyl alcohol) or silicon or comprise a surface treatment comprising PVOH or silicon. Only the first layer may comprise PVOH (polyvinyl alcohol) or silicon or comprise a surface treatment comprising PVOH or silicon. Only the second layer may comprise PVOH (polyvinyl alcohol) or silicon or comprise a surface treatment comprising PVOH or silicon.

Aerosol-generating articles include an aerosol-generating substrate that may comprise a tobacco filler circumscribed by the wrapper described herein. The aerosol-generating substrate may comprise any suitable type or types of tobacco or tobacco substitute material, in any suitable form. The aerosol-generating substrate may include atmosphere-cured tobacco, Burley tobacco, Maryland tobacco, Oriental tobacco, specialty tobacco, homogenized or reconstituted tobacco, or any combination thereof. The aerosol-generating substrate may be provided in the form of tobacco cut, tobacco sheet, processed tobacco materials, such as bulk-expanded or puffed tobacco, processed tobacco stems, such as rolled cut or puffed cut stems, homogenized tobacco, reconstituted tobacco, molded leaf tobacco, or mixtures thereof, and the like. The term "tobacco cut" is used herein to indicate a tobacco material that is predominantly formed from the sheet portion of the tobacco leaf. The term “split tobacco” is used herein to indicate either a single Nicotiana species or two or more Nicotiana species that form a mixture of cut tobacco.

When used herein, the term “homogenized tobacco” denotes a material formed by agglomerating tobacco into particles. Homogenized tobacco may include reconstituted tobacco or reconstituted tobacco sheet tobacco, or a mixture of both. The term “reconstituted tobacco” refers to a paper-like material that may be made from tobacco by-products, such as very short tobacco fibers, tobacco dust, tobacco stems, or a mixture of the foregoing. Reconstituted tobacco may be made by extracting the soluble chemicals in the tobacco by-products, processing the remaining tobacco fibers into a sheet, and then reapplying the extracted materials in concentrated form to the sheet. The term “reconstituted tobacco sheet tobacco” is used herein to refer to a product resulting from a process well known in the art, which is based on straining a slurry comprising ground tobacco particles and a binder (e.g., guar) onto a support surface, such as a conveyor belt, 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 US 5,724,998; US 5,584,306; US 4,341,228; US 5,584,306 and US 6,216,706. The homogenized tobacco may be formed into a sheet that is crimped, convoluted, folded, or otherwise compressed, prior to being wrapped to form a rod. For example, sheets of homogenized tobacco material for use in the invention may be curled by the use of a curling unit of the type described in CH-A-691156, comprising a pair of rotatable curling rollers. However, it will be appreciated that sheets of homogenized tobacco material for use in the invention may be textured by the use of other suitable machinery and processes which deform or perforate the sheets of homogenized tobacco material.

The aerosol-generating substrate used in aerosol-generating articles typically includes a higher level of aerosol former(s) than combustible smoking articles, such as cigarettes. Humectants may also be referred to as an “aerosol former.” An aerosol former is used to describe any known suitable compound or mixture of compounds that, in use, facilitates the formation of an aerosol and is substantially resistant to thermal degradation 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, such as propylene glycol, triethylene glycol, 1,3-butanediol, and glycerin; esters of polyhydric alcohols, such as glycerin mono-, di-, or triacetate; and aliphatic esters of mono-, di-, or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate. Preferred aerosol formers are polyhydric alcohols or mixtures thereof, such as propylene glycol, triethylene glycol, 1,3-butanediol and most preferably glycerol or glycerine. The aerosol-generating substrate may comprise a single aerosol-forming agent. Alternatively, the aerosol-generating substrate may comprise a combination of two or more aerosol-forming agents.

The aerosol-generating substrate has 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%, or preferably greater than about 15%, or more preferably greater than about 20%, by weight. The aerosol-generating substrate may also have an aerosol former content of between about 10% and about 30%, about 15% and about 30%, or about 20% and about 30%, by weight. The aerosol-generating substrate may also have a glycerin content of between about 10% and about 30%, about 15% and about 30%, or about 20% and about 30%, by weight.

The aerosol-generating substrate comprises at least about 10%, or at least about 12%, or at least about 15%, or at least about 18% aerosol former, by weight. The aerosol-generating substrate may comprise an aerosol former in a range of about 10 to about 20%, by weight.

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

Aerosol-generating substrates in gel form may have a majority of aerosol formers, preferably glycerin. The gel composition may include a solid-forming gelling agent, 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 solid-forming gelling agents, 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 viscosifying agent, and a solid-forming gelling agent, glycerin dispersed in the solid medium, and nicotine dispersed in the glycerin. The composition forms a stable gel phase. A gel composition may include nicotine, an aerosol former, a viscosifying agent, a hydrogen-bonded cross-linking gelling agent, and an ionic cross-linking gelling agent. The gel composition may further include divalent cations.

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

The wrapper, described herein, is disposed around an aerosol-generating substrate. The wrapper may reduce the absorption of aerosol-forming compounds and water into the wrapper as air is drawn through the heated aerosol-generating article.

Preferably, the aerosol-generating article may be generally cylindrical. This allows for a smooth flow of the aerosol. The aerosol-generating article may have an external diameter, for example, between 4 millimetres and 15 millimetres, between 5 millimetres and 10 millimetres, or between 6 millimetres and 8 millimetres. The aerosol-generating article may have a length, for example, between 10 millimetres and 60 millimetres, between 15 millimetres and 50 millimetres, or between 20 millimetres and 45 millimetres.

The resistance to aspiration (RTD) of the aerosol-generating article will vary depending on, among other things, the length and dimensions of the passageways, the size of the openings, the dimensions of the most restricted cross-sectional area of the internal passageway, and the materials used. The RTD of the aerosol-generating article may be between 50 millimeters of water (mm H2O) and 140 millimeters of water (mm H2O), between 60 millimeters of water (mm H2O) and 120 millimeters of water (mm H2O), or between 80 millimeters of water (mm H2O) and 100 millimeters of water (mm H2O). The RTD of the article refers to the static pressure difference between one or more openings and the mouth-side end of the article as the article is passed through an internal longitudinal passageway under steady-state conditions where the volumetric flow rate is 17.5 milliliters per second at the mouth-side end. The RTD of a sample can be measured using the method set out in ISO 6565:2002.

All scientific and technical terms used in this description have meanings that are commonly used in the art unless otherwise specified. The definitions provided in this description are to facilitate understanding of certain terms frequently used in this description.

As used in this description and the appended claims, the singular forms “a,” “an,” and “the” encompass embodiments having plural referents, unless the content clearly indicates otherwise.

As used in this description and the appended claims, the term “or” is generally used in a sense that includes “and/or” unless the content clearly indicates otherwise.

As used herein, “has,” “having,” “includes,” “including,” “comprises,” “comprising,” or the like are used in their broad sense, and generally imply “including, but not limited to.” The expression “consisting essentially of,” “consists of,” and the like should be understood to be included in “comprising” and the like.

The words “preferred” and “preferably” refer to embodiments of the invention that may achieve certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the listing 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 description, which includes the claims.

Figure 1 is a cross-sectional schematic diagram of an aerosol-generating article. Figure 2 is a cross-sectional schematic diagram of another aerosol-generating article. Figure 3 is a cross-sectional schematic diagram of another aerosol-generating article. Figure 4 is a cross-sectional schematic diagram of another aerosol-generating article. Figure 5 and Figure 6 are cross-sectional schematic diagrams of an aerosol-generating system.

The aerosol-generating articles depicted in Figures 1-4 illustrate one or more embodiments of 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 and are not exhaustive. The drawings depict one or more aspects described in this disclosure. However, it will be understood that other aspects not depicted in the drawings fall within the scope of this disclosure.

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

The aerosol generating substrate 12, the hollow cellulose acetate tube 14, and a polylactic acid filter segment 16 are joined together and circumscribed by a second layer of paper 20 to form an intermediate article. The nozzle segment 18 is joined to the intermediate article with nozzle paper 25 to form the aerosol generating article 10. The first layer of paper 50 and the second layer of paper 20 may cooperate to form the wrapper as described herein.

The aerosol-generating article 10 has a mouth-side end 22 and an upstream distal end 24 located at the opposite end of the article to the mouth-side end 22. The aerosol-generating article 10 shown in Figure 1 is particularly suitable for use with an electrically operated aerosol-generating device comprising a heater for heating the aerosol-generating substrate 12.

The aerosol-generating article 100 of Figure 2 comprises four elements arranged in coaxial alignment: a high draw resistance (RTD) end cap 600 at the distal end 103, a first paper layer 500 circumscribing an aerosol-generating substrate 124, a fluid guide 400, and a nozzle 170 at the proximal end 101. These four elements are sequentially arranged and circumscribed by a second paper layer 110 to form the aerosol-generating article 100. The aerosol-generating article 100 has a proximal or mouth-side end 101, and a distal end 103 located at the opposite end of the aerosol-generating article 100 with respect to the proximal end 101. The first paper layer 500 and the second paper layer 110 cooperate to form the overwrap, as described herein.

The aerosol generating article 100 of Figure 3 illustrates, in a cutaway view, an example of an aerosol generating article 100 that is suitable for induction heating as well as heating with a foil-type heating element.

The aerosol-generating article 100 comprises a nozzle 170 at the proximal end 101, a fluid guide 400, a cavity 700, a first paper layer 500 circumscribing an aerosol-generating substrate 124, and an end plug 600 in proximal to distal order. In this example, the aerosol-generating substrate 124 comprises a gel and a susceptor (not shown). The susceptor in this example is a single aluminum strip centrally located along the longitudinal axis of the aerosol-generating substrate 124. By inserting the distal end 103 of the aerosol-generating article 100 into an aerosol-generating device 200 (see Figure 6) such that the portion of the aerosol-generating article 100 is positioned to be near the induction heating elements 230 (see Figure 5) of the aerosol-generating device 200 (see Figure 6). The electromagnetic radiation produced by the induction heating elements 230 is absorbed by the susceptor and assists in heating the aerosol generating substrate 124 in the first paper layer 500, in turn assisting in the release of material from the aerosol generating substrate 124, for example nicotine entrained into the passing aerosol when a negative pressure is applied at the proximal end 101 of the aerosol generating article 100. Fluid, for example air, enters the outer longitudinal passages 831 through openings (not shown) to be transferred to the cavity 700 and then to the aerosol generating substrate 124 where the fluid mixes with the aerosol generating substrate 124 and is entrained with nicotine before returning to the cavity and then through the inner longitudinal passage (not shown) of the fluid guide 400 before exiting the proximal end 101.

In this example, a first layer of paper 500 circumscribes an aerosol-generating substrate 124 and the first layer of paper 500 is circumscribed by a second layer of paper 110. The first layer of paper 500 and the second layer of paper 110 form the wrapper, as described herein. The aerosol-generating substrate 124 may include a gel composition.

This aerosol generating article 100 illustrated in Figure 2 and Figure 3 can be used with the aerosol generating device 200 as illustrated in Figure 5 and Figure 6.

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 nozzle segment 18. The aerosol-generating substrate 12 is wrapped with a first layer of paper 50, as described herein. These four elements are arranged longitudinally aligned from end to end and are circumscribed by a second layer of paper 20 to form the aerosol-generating article 10. The first layer of paper 50 and the second layer of paper 20 may cooperate to form the wrapper as described herein.

The aerosol-generating article 10 has a mouth-side end 22 and an upstream distal end 24 located at the opposite end of the article to the mouth-side end 22. The aerosol-generating article 10 shown in Figure 4 is particularly suitable for use with an electrically operated aerosol-generating device comprising a heater for heating the aerosol-generating substrate 12.

The aerosol-generating substrate 12 has a length of about 12 millimeters and a diameter of about 7 millimeters. The aerosol-generating substrate 12 has a cylindrical shape and an essentially circular cross section. The aerosol-generating substrate 12 comprises a shirred sheet of homogenized tobacco material. The sheet of homogenized tobacco material comprises 10 weight percent on a dry basis glycerin. The hollow cellulose acetate tube 14 has a length of about 8 millimeters and a thickness of 1 millimeter. The mouthpiece segment 18 comprises a cellulose acetate tow plug of 8 denier per filament and has a length of about 7 millimeters.

The hollow tubular segment 14 is provided as a cylindrical tube having a length of about 18 millimeters and a tube wall thickness of about 100 micrometers. The aerosol-generating article 10 comprises a vent zone 26 that is provided about 5 millimeters from an upstream end of the nozzle segment 18. Thus, the vent zone 26 is located about 12 millimeters from the downstream end of the aerosol-generating article and about 13 millimeters from the upstream end of the hollow tubular segment. Thus, the vent zone 26 is located about 21 millimeters from a downstream end of the aerosol-generating substrate 12.

Figures 5-6 illustrate an example of an aerosol-generating article 100 and an aerosol-generating device 200. The aerosol-generating article 100 has a mouth-side or proximal end 101 and a distal end 103. In Figure 5, the distal end 103 of the aerosol-generating article 100 is received in a receptacle 220 of the aerosol-generating device 200. The aerosol-generating device 200 includes a housing 210 defining the receptacle 220, which is configured to receive the aerosol-generating article 100. The aerosol-generating device 200 also includes a heating element 230 forming a cavity 235 configured to receive the aerosol-generating article 100, preferably by a press fit. The heating element 230 may comprise an electrically resistive heating component. Furthermore, the device 200 includes a power supply 240 and electronic control circuits 250 that cooperate to control the heating of the heating element 230.

The heating element 230 may heat the distal end 103 of the aerosol-generating article 100. In this example, the aerosol-generating substrate 124 comprises a gel comprising nicotine. Heating the aerosol-generating article 100 causes the aerosol-generating substrate 124 to generate an aerosol containing the nicotine that may be transferred out of 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.

In some examples, the heating mechanism could be by conduction heating where heat is transferred from the heating element 230 of the aerosol generating device 200 to the aerosol generating article 100. This can easily take place when the aerosol generating article 100 is positioned in the receptacle 220 of the aerosol generating device 200 and the distal end 103 (which is 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 specific examples the heating element comprises a heating sheet protruding from the aerosol generating device 200 and suitable for penetrating the aerosol generating article 100 to make direct contact with the aerosol generating substrate 124.

In this example, the heating mechanism is by induction where the heating element emits radiomagnetic radiation that is absorbed by the tubular element when the aerosol generating article 100 is positioned in the receptacle 220 of the aerosol generating device 200.

Once the aerosol generating article 100 is releasably received in the aerosol generating device 200 and the heating element 230, the aerosol generating device 200 is actuated to heat the aerosol generating substrate 124 to a temperature of about 375 degrees Celsius. When a user draws on the mouth-side 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 into the user's mouth. The wrapper 500, 110 repels aerosol former and moisture from the aerosol to reduce staining and weakening of the wrapper 500, 110.

The first layer of paper 50, 500 has a thickness/grammage of about 1.2 micrometers/g/m2 or less. Preferably the first layer of paper 50, 500 has a thickness/grammage in a range of about 1.0 micrometers/g/m2 to about 1.2 micrometers/g/mf. The first layer of paper 50, 500 may have a thickness of less than about 50 micrometers, or less than about 40 micrometers. The first layer of paper 50, 500 may have a basis weight in a range of about 25 g/m2 to about 45 g/m2, or about 35 g/m2 to about 40 g/m2.

Preferably, the first paper layer 50, 500 has a thickness/grammage of about 1.2 microns/g/m2 or less and a water contact angle of at least about 30 degrees. The first paper layer 50, layer 500 may have a water contact angle of at least about 40 degrees, or at least about 45 degrees.

Preferably, the first layer of paper 50, 500 has a thickness/grammage of about 1.2 microns/g/m2 or less and a CD/MD elongation at break ratio of about 2.5 or less. The first layer of paper 50, 500 may have a CD/MD elongation at break ratio of about 2.2 or less, or about 2 or less.

Preferably, the first layer of paper 50, 500 has a thickness/grammage of about 1.2 microns/g/m2 or less and a negative result for at least one oil sample from the Tappi Method 559 cm-02 Classic Method 2002 kit. The first layer of paper 50, 500 may have a negative result for at least five oil samples from the kit, or all ten oil samples from the Tappi Method 559 cm-02 Classic Method 2002 kit.

Preferably, the wrapper includes the first paper layer 50, 500 and the second paper layer 20, 110 wherein the first paper layer 50, 500 has a first thickness/grammage value and the second paper layer 20, 110 has a second thickness/grammage value and the first thickness/grammage value is less than the second thickness/grammage value. The first thickness/grammage value may be less than 1.2 microns/g/mP and the wrapper may have a total thickness of less than about 80 microns.

Preferably the first paper layer 50, 500 comprises PVOH (polyvinyl alcohol) or silicon. The first paper layer 50, 500 may comprise a surface treatment comprising PVOH or silicon. The addition of PVOH (polyvinyl alcohol) or silicon may improve the grease barrier properties of the wrapper.

Preferably the second paper layer 20, 110 comprises PVOH (polyvinyl alcohol) or silicon. The second paper layer 20, 110 may comprise a surface treatment comprising PVOH or silicon. The addition of PVOH (polyvinyl alcohol) or silicon may improve the grease barrier properties of the wrapper.

The illustrative embodiments described above are not limiting. Other embodiments consistent with the illustrative embodiments described above will be apparent to those skilled in the art.

Claims (13)

1. An aerosol generating article (10, 100) comprising: an aerosol-generating substrate (12, 124) comprising nicotine and at least about 10% aerosol former comprising glycerin; and an overwrap disposed around and in contact with the aerosol-generating substrate, wherein the overwrap comprises a paper layer (50, 500, 20, 110) having a thickness/grammage of about 1.2 microns/g/m2 or less, and wherein the paper layer comprises a surface treatment comprising PVOH or silicon. 2. The aerosol-generating article according to claim 1, wherein the paper layer has a thickness/grammage in a range of about 1.0 micron/g/mf to about 1.2 microns/g/m2. 3. The aerosol-generating article according to any preceding claim, wherein the paper layer has a thickness of less than about 50 microns, or less than about 40 microns. 4. The aerosol-generating article according to any preceding claim, wherein the paper layer has a basis weight in a range of about 25 g/m2 to about 45 g/m2, or about 35 g/m2 to about 40 g/m2. 5. The aerosol-generating article according to any preceding claim, wherein the paper layer comprises PVOH. 6. The aerosol-generating article according to any preceding claim, wherein the paper layer comprises silicon. 7. The aerosol-generating article according to any preceding claim, wherein the aerosol-generating substrate comprises a gel composition. 8. The aerosol-generating article according to claim 7, wherein the gel composition comprises a majority of glycerin. 9. The aerosol-generating article according to claim 8, wherein the gel composition comprises xanthan gum. 10. The aerosol-generating article according to any preceding claim, wherein the aerosol-generating substrate comprises homogenized tobacco material. 11. The aerosol-generating article according to claim 10, wherein the homogenized tobacco material comprises tobacco material, from about 1% to about 5% of a binder, and from about 5% to about 30% of an aerosol former, on a dry weight basis. 12. The aerosol-generating article according to any preceding claim, wherein the aerosol-generating substrate comprises a metal induction heating element. 13. The aerosol-generating article according to any preceding claim, wherein the aerosol-generating substrate comprises a plurality of metallic induction heating elements.