Stable Wrapper for Aerosol Generating Article

This is a continuation application of U.S. patent application Ser. No. 17/612,742, filed 19 Nov. 2021, which is a § 371 U.S. National Stage of International Application No. PCT/IB2020/055368, filed 8 Jun. 2020, which claims the benefit of European Application No. 19179250.6, filed 10 Jun. 2019. The disclosure of any priority document claimed is incorporated by reference herein in its entirety.

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

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 the transfer of 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 air drawn through the aerosol generating article. As the released compounds cool, they condense to form an aerosol.

Paper that is used to wrap the aerosol generating substrate can absorb aerosol former, water and other liquid compounds found in the mainstream smoke or aerosol passing through the aerosol generating article, or humidity or moisture surrounding the paper. The absorbed liquid may stain or weaken the paper and negatively affects 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 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 wrapper, leading to difficult removal from the heating device. Heated aerosol generating articles are particularly susceptible to breakage when they are tightly received and then removed from a heating device.

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

It would be desirable to provide an aerosol generating article that included a wrapper that did not swell up by absorbing water or compounds contained in the aerosol generating substrate.

It would be desirable to provide an aerosol generating article that included a wrapper that provided a grease barrier to grease compounds contained in the aerosol generating substrate.

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

It would also be desirable that this wrapper not readily burn if proximate a heating element.

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

According to this disclosure, there is provided an aerosol generating article comprising an aerosol generating substrate comprising nicotine, and a wrapper disposed about the aerosol generating substrate. The wrapper comprises a paper layer having a thickness/grammage of about 1.2 micrometers/gsm or less.

According to this disclosure, there is provided an aerosol generating article comprising an aerosol generating substrate comprising nicotine and at least about 10% aerosol former comprising glycerine, and a wrapper disposed about and in contact with the aerosol generating substrate. The wrapper comprises a paper layer having a thickness/grammage of about 1.2 micrometers/gsm or less.

According to this disclosure, there is provided an aerosol generating article. The aerosol generating article may comprise an aerosol generating substrate. The aerosol generating substrate may include a wrapper. The wrapper may be disposed about the aerosol generating substrate. The wrapper includes a paper layer having a thickness/grammage of about 1.2 micrometers/gsm or less.

Preferably the paper layer has a thickness/grammage in a range from about 1.0 micrometers/gsm to about 1.2 micrometers/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 grammage in a range from about 25 gsm to about 45 gsm, or from about 35 gsm to about 40 gsm.

Preferably, the paper layer has a thickness/grammage 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.

The term “MD” refers to a machine-direction of the wrapper. The machine-direction is the direction paper stock flows into and through a papermaking machine. The machine-direction is the circumferential direction of a roll of paper being wound up from the paper machine. The machine-direction may also be referred to as the grain direction.

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

The paper layer may have an elongation to break ratio CD/MD of about 2.5 or less. The paper layer may have an elongation to break ratio CD/MD of about 2.2 or less, or about 2 or less. The paper layer may have an elongation to break ratio CD/MD in a range from about 1.8 to 2.2.

Preferably, the wrapper comprises a paper layer having a thickness/grammage of about 1.2 micrometers/gsm or less and a negative result for at least one kit oil sample of method Tappi 559 cm-02 classical method. The paper layer may have a negative result for at least five kit oil samples, or all ten kit oil samples of method Tappi 559 cm-02 classical method.

Preferably, the wrapper includes two paper layers wherein a first paper layer has a first thickness/grammage value and the second paper layer 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 micrometers/gsm and the wrapper may have a total thickness of less than about 80 micrometers.

Preferably, the paper layer comprises PVOH (polyvinyl alcohol) or silicon. The paper layer may comprise a surface treatment comprising PVOH or silicon. 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 tobacco 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, in dry weight basis.

Preferably, the aerosol generating substrate may comprise a gel composition. The gel composition may comprise a majority (by weight) of glycerine. 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 plurality of metallic induction heating elements. The metallic induction heating element may comprise a metallic induction heating ring element.

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

Preferably the wrapper covers at least 20%, at least 50%, at least 80%, at least 90%, at least 95%, at least 99% or preferentially about the full length (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.

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

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

Advantageously, aerosol generating articles that include a wrapper described herein may reduce wetting, absorption of 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 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 avoids swelling. This is particularly useful for heat-not-burn aerosol generating articles that may be inserted into heating device. The aerosol generating article wrapper resists burning if proximate a heating element, thus inductive heating elements may be incorporated throughout the aerosol generating substrate.

The term “aerosol generating article” is used herein to denote an article wherein 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 localised heat provided by the flame and the oxygen in the air drawn through the cigarette causes the end of the cigarette to ignite, and the resulting combustion generates an inhalable smoke. By contrast, in heated aerosol generating articles, an aerosol is generated by heating a flavour generating substrate, such as tobacco. Known heated aerosol generating articles include, for example, electrically heated aerosol generating articles and aerosol generating articles in which an aerosol is generated by the transfer of heat from a 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 heater blade which is adapted to be inserted into the rod of 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 heater element that interacts with the aerosol generating substrate of the 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 substance capable of generating or releasing an aerosol. The aerosol generating substrate may be a solid, paste, gel, slurry, liquid, or comprise any combination of solid, paste, gel, slurry, and liquid compounds. 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 mouthpiece. The mouthpiece may comprise a filter. A tipping wrapper may join the filter to the aerosol generating substrate.

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

Nicotine may be present in the aerosol generating substrate in a range from about 0.5 to about 10% wt, nicotine, or about 0.5 to about 5% wt. nicotine. Preferably the aerosol generating substrate may include about 1 to about 3% wt, nicotine, or about 1.5 to about 2.5% wt. nicotine, or about 2% wt nicotine.

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

The aerosol generating substrate may include an essential oil. Essential oils may provide flavourant that may impart a flavour 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. 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. Essential oil may be present in the aerosol generating substrate in a range from about 0.1% by weight to about 10% by weight, or from about 0.1% by weight to about 5% by weight, or from 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 may be defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state. By weight, gels may be mostly liquid, yet they behave like solids due to a three-dimensional cross-linked network within the liquid. It is the crosslinking within the fluid that gives a gel its structure (hardness). In this way gels may be a dispersion of molecules of a liquid within a solid in which liquid particles are dispersed in the solid medium.

The gel composition may include a gelling agent forming a solid medium, an aerosol former such as glycerine dispersed in the solid medium, and nicotine dispersed in the glycerine. The composition forming a stable gel phase. The gel composition may include at least two gelling agents forming a solid medium, glycerine dispersed in the solid medium, and nicotine dispersed in the glycerine. The composition forming a stable gel phase. The gel composition may include a viscosifying agent, and gelling agent forming a solid medium, glycerine dispersed in the solid medium, and nicotine dispersed in the glycerine. The composition forming a stable gel phase. A gel composition may include nicotine, an aerosol former, a viscosifying agent, a hydrogen-bond crosslinking gelling agent, and an ionic crosslinking gelling agent. The gel composition may further include divalent cations.

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

The viscosity values recited herein can be measured using Brookfield RVT viscometer rotating a disc type RV #2 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% wt. water/50% wt. glycerine mixture, in an amount of about 0.3% wt, forms a solid medium or support matrix leading to a gel. Gelling agents include, but not limited to, hydrogen-bond crosslinking gelling agents, and ionic crosslinking gelling agents.

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

The term “ionic crosslinking gelling agent” refers to a gelling agent that forms non-covalent crosslinking bonds or physical crosslinking bonds via ionic bonding. Ionic crosslinking involves the association of polymer chains by noncovalent interactions. A crosslinked network is formed when multivalent molecules of opposite charges electrostatically attract each other giving rise to a crosslinked polymeric 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 glycerine; esters of polyhydric alcohols, such as glycerine mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate. Polyhydric alcohols or mixtures thereof, may be one or more of triethylene glycol, 1,3-butanediol and, glycerine (glycerine or propane-1,2,3-triol) or polyethylene glycol. The aerosol former is preferably glycerine.

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