Patent Description:
Smoking articles such as cigarettes, cigars and the like burn tobacco during use to create tobacco smoke. An example of such a smoking article is disclosed in <CIT>. Alternatives to these types of articles, release compounds by heating without burning an aerosolisable material. An example of such an article is disclosed in <CIT>.

Apparatus is known that heats aerosolisable material to volatilise at least one component of the aerosolisable material, typically to form an aerosol which can be inhaled, without burning or combusting the aerosolisable material. Such apparatus is sometimes described as a "heat-not-burn" apparatus or a "tobacco heating product" (THP) or a "tobacco heating device" or similar. Various different arrangements for volatilising at least one component of the aerosolisable material are known.

The material may be for example tobacco, other non-tobacco products or a combination, such as a blended mix, which may or may not contain nicotine.

The invention provides an aerosol generating article according to appended claim <NUM>.

Further aspects are disclosed in appended claims <NUM>-<NUM>.

Further features and advantages of the invention will become apparent from the following figures description of examples of the invention, given by way of example only.

As used herein, the term "laminate structure" refers to a multi-layer structure in which the layers are fastened together to form a single body. The layers may be fastened with an adhesive, for example. In other examples, the layers may be fastened by static interaction. In other examples, the laminate structure might be formed by (partially) melting a first layer, contacting the first layer with a second layer and allowing the first layer to solidify. Any suitable mechanism for fastening the layers together including, but not limited to, the above examples, tying, sewing, screwing, nailing, bolting, hooking etc. may be employed to form the laminate structure.

In some cases, an adhesive may coat the surface of each layer. In other cases, an adhesive may be applied only to the periphery of the layers. In some cases, each layer in the laminate structure may be fastened to the adjacent layer(s). In some example laminate structures, the periphery of two layers may be fastened together with intermediate layers trapped in-between.

In one example of the wrapper, the laminate structure may comprise the intermediate layer and the peripheral layer which is disposed adjacent to the aerosolisable material in use (i.e. the innermost layer). This may then be circumscribed or wrapped by one or more further layers, wherein the peripheral layer of the composite structure comprises paper (i.e. the outermost layer). <FIG> is a schematic illustration of such an example. The laminate structure (indicated by dotted lines) includes a peripheral layer <NUM> and the intermediate layer <NUM>. The wrapper additionally comprises peripheral layer <NUM>, although this is not part of the laminate structure.

In another example, the laminate structure comprises each of the peripheral layers and the intermediate layer. That is, in one example, the laminate wrapper for wrapping an aerosolisable material comprises at least three layers, wherein the peripheral (i.e. the innermost and outermost) layers comprise paper and an intermediate layer comprises a non-combustible material. <FIG> is a schematic illustration of such an example. The laminate structure (indicated by dotted lines) includes the peripheral layers <NUM>,<NUM> and the intermediate layer <NUM>.

In some cases, the non-combustible material comprises a metal foil. In some cases, it may consist essentially of or consist of a metal foil. Suitably, the metal foil may comprise, essentially consist of or consist of an aluminium foil. The metal foil is a non-combustible material that can nevertheless act to conduct heat to the aerosolisable material in use.

In some cases, the metal foil may be less than about <NUM>, <NUM>, <NUM>, <NUM> or <NUM> thick. In some cases, it may be more than about <NUM>, <NUM> or <NUM> thick.

In some cases, the wrapper may be a laminate wrapping material that consists of three layers (i.e. only the innermost and outermost layers comprising paper and the intermediate non-combustible layer). In some cases, the wrapper may consist of a three layer laminate structure comprising the peripheral layers and the intermediate layer.

In some cases, the innermost and outermost layers of the wrapper are tobacco wrapping paper.

A consideration when preparing aerosol generating articles such as tobacco heating products is that they should not produce an acceptable smoking experience if combusted, so that the user is not minded to burn the aerosol generating article. This is because the formulation of the aerosolisable material is not configured for combustion (and the aerosol that results from combustion may be less suitable for inhalation than the aerosol that results from heating but not burning that aerosolisable material, or than the aerosol which results from combustion of traditional cigarettes).

The use of a non-combustible layer in the wrapper prevents the aerosol generating article from being burned and smoked as a conventional combustible cigarette.

As used herein, the phrase "non-combustible" refers to a material that will not ignite or burn at temperatures normally associated with lighting (igniting) or burning of tobacco.

Further, the use of a metal foil layer results in a wrapper that has a low porosity, reducing side stream air flow to the aerosolisable material. This further reduces the propensity to burn through limiting the oxygen levels at the aerosolisable material.

Moreover, the inventors established that having paper in the innermost and outermost layers of a laminate wrapper may be beneficial because the laminate surfaces then have a coefficient of friction of that paper. This means that the laminate wrapper can be more readily used in known cigarette manufacturing processes and machines. The laminate surfaces having a coefficient of friction equivalent to that of a cigarette paper allows the garniture belt of an aerosol generating article making machine to drive the laminate wrapper through the garniture during the aerosol generating article manufacturing process.

In some cases, the innermost layer may also comprise a flavourant, which is transferred to the aerosolisable material when wrapped around the aerosolisable material and heated. In some cases, the flavourant is impregnated into paper in the innermost layer. In some cases, the flavourant may comprise menthol.

The inventors established that having paper in the innermost layer of the laminate material may be beneficial because it can act as a flavour carrier.

According to the invention, the paper in either or each of the innermost and outermost layers of the laminate has a basis weight of <NUM>/m<NUM> to <NUM>/m<NUM>. Paper having a density in this range has a low porosity, which further reduces the propensity to burn through limiting the oxygen levels at the aerosolisable material.

In some cases, the paper in either or each of the innermost and outermost layers of the wrapper may be treated with one or more burn-retardant substances.

In one example, the wrapper is a laminate structure that consists of:.

In one example, the wrapper comprises a laminate structure that consists of:.

In this example, the wrapper additionally comprises a second paper layer which is wrapped over the laminate in use, the second paper layer having a basis weight of <NUM>-<NUM>.

In some cases, the laminate material can be wound onto a bobbin core for use with standard cigarette makers that are fed from a single paper bobbin.

In some cases, one or more ventilation apertures may be formed in the wrapper. The ventilation apertures may provide airflow into the aerosol-generating article during use, the air forming part of the inhaled aerosol.

The laminate structure may be formed using any suitable lamination technique. In one example, the layers may be adhered together.

According to the invention, the innermost layer is disposed in contact with the aerosolisable material.

In some cases, the aerosolisable material comprises tobacco. The tobacco may be any suitable solid tobacco, such as single grades or blends, cut rag or whole leaf, ground tobacco, tobacco fibre, cut tobacco, extruded tobacco, tobacco stem and/or reconstituted tobacco. The tobacco may be of any type including, but not limited to, Virginia and/or Burley and/or Oriental tobacco.

In some examples, the aerosolisable material may be a rod of aerosolisable material. As used herein, the term "rod" generally refers to an elongate body which may be any suitable shape for use in an aerosol generating assembly. In some cases, the rod is substantially cylindrical.

In some cases where the aerosolisable material is a rod of aerosolisable material, the wrapper circumscribes at least the end of the rod that is distant from the user's mouth in use (i.e. a distal-end rather than a mouth-end). This ensures that the non-combustible wrapper is disposed around the end of the rod which the user might try to ignite. In some cases, the laminate wrapper circumscribes the rod over at least <NUM>% of the rod length. In some cases, the wrapper extends over at least <NUM>%, <NUM>%, <NUM>% or <NUM>% of the rod length. As more of the rod is circumscribed, burning of the rod is more difficult.

In some cases, the wrapper does not extend over the entire length of the rod of aerosolisable material, resulting in cost savings. In some cases, the laminate wrapper extends over less than about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% or <NUM>% of the rod length.

<FIG> illustrates an example aerosol generating article. The aerosol generating article <NUM> includes an aerosolisable material <NUM> which is wrapped by a wrapper <NUM>. In this example, this wrapper extends from the distal-end of the aerosolisable material over approximately <NUM>% of the distance to the mouth-end of the aerosolisable material. In some examples, the wrapper <NUM> comprises three layers, wherein the peripheral layers comprise paper and an intermediate layer comprises a non-combustible material. In some examples, one peripheral layer and the intermediate layer are provided as a laminate structure (see <FIG>). In other examples, both peripheral layers and the intermediate layer are provided as a laminate structure (see <FIG>).

Optionally, the wrapper may also be arranged over the distal-end of the aerosolisable material, so that the distal-end is completely enclosed in the wrapper. <FIG> illustrates an example in which the wrapper <NUM> is wrapped around the circumference of the aerosolisable material <NUM>. The distal-end of the aerosol generating article <NUM> is not covered by the wrapper. <FIG> illustrates an alternative example of an aerosol generating article <NUM> in which the wrapper <NUM> completely encloses the distal-end of the aerosol generating article.

Examples of the aerosol generating article may additionally comprise a filter and/or a cooling element. In some cases, these additional components may not be circumscribed by all layers of the wrapper; instead, they may be circumscribed by a single layer of the wrapper which extends over a greater proportion of the aerosolisable material than the other layers. Suitably, the additional components may be circumscribed by only the outermost peripheral layer of the wrapper (which also circumscribes the aerosolisable material) or alternatively, by only the innermost peripheral layer of the wrapper.

For example, the mouth-end of the aerosolisable material may be provided adjacent to one or more of a cooling element and a filter. A cooling element, if present, allows vapour components to condense to form an aerosol and/or spaces the very hot parts of the apparatus from the user. A filter, if present, may remove components from the fluid flow, affecting the chemical composition of the inhaled aerosol.

<FIG> illustrates an example of an aerosol generating article <NUM> which includes, in addition to the features of <FIG>, a cooling element <NUM>, a filter <NUM> and a mouth-end tube <NUM>. The cooling element <NUM> and filter <NUM>, as illustrated, may be arranged between the mouth-end of the aerosolisable material <NUM> and the mouth-end tube <NUM>, so that flow from the aerosolisable material <NUM> passes through the cooling element <NUM> and filter <NUM> (or vice versa if the filter is arranged before the cooling element in the flow) before reaching the user. Although the example in <FIG> illustrates a cooling element <NUM>, a filter <NUM> and a mouth-end tube <NUM>, one or more of these elements may be omitted in other examples.

In some examples, the mouth-end tube, if present, <NUM> may be formed of for example paper, for example in the form of a spirally wound paper tube, cellulose acetate, cardboard, crimped paper, such as crimped heat resistant paper or crimped parchment paper, and/or polymeric materials, such as low density polyethylene (LDPE), or some other suitable material. The mouth-end tube <NUM> may be a hollow tube. Such a hollow tube may provide a filtering function to filter volatilised aerosolisable material. The mouth-end tube <NUM> may be elongate, in order to be spaced from the very hot part(s) of the main apparatus (not shown) that heats the aerosolisable material.

In some examples, the filter <NUM>, if present, may be a filter plug, and may be made, for example, from cellulose acetate.

In some cases, the cooling element <NUM>, if present, may comprise a monolithic rod having first and second ends and comprising plural through holes extending between the first and second ends. The through holes may extend substantially parallel to the central longitudinal axis of the rod. The through holes of the cooling element <NUM> may be arranged generally radially of the element when viewed in lateral cross-section. That is, in an example, the element has internal walls which define the through holes and which have two main configurations, namely radial walls and central walls. The radial walls extend along radii of the cross-section of the element and the central walls are centred on the centre of the cross-section of the element. The central walls in one example are circular, though other regular or irregular cross-sectional shapes may be used. Likewise, the cross-section of the element in one example is circular, though other regular or irregular cross-sectional shapes may be used.

In an example, the majority of the through holes have a hexagonal or generally hexagonal cross-sectional shape. In this example, the element has what might be termed a "honeycomb" structure when viewed from one end.

In some cases, the cooling element <NUM> may comprise a hollow tube which spaces the filter <NUM>, if present, from the very hot part(s) of the main apparatus that heats the aerosolisable material. The cooling element <NUM> may be formed of for example paper, for example in the form of a spirally wound paper tube, cellulose acetate, cardboard, crimped paper, such as crimped heat resistant paper or crimped parchment paper, and polymeric materials, such as low density polyethylene (LDPE), or some other suitable material.

The cooling element <NUM>, if present, may be substantially incompressible. It may be formed of a ceramic material, or of a polymer, for example a thermoplastic polymer, which may be an extrudable plastics material. In an example, the porosity of the element is in the range <NUM>% to <NUM>%. The porosity in this sense may be a measure of the percentage of the lateral cross-sectional area of the element occupied by the through holes. In an example, the porosity of the element is around <NUM>% to <NUM>%.

Other examples of aerosol-cooling element are disclosed in <CIT>, in particular in Figures <NUM> to <NUM> and the description from page <NUM>, line <NUM> to page <NUM>, line <NUM>.

In further examples, the cooling element <NUM> may be formed from a sheet material that is folded, crimped or pleated to form through holes. The sheet material may be made, for example, from metal such as aluminium; polymeric plastics material such as polyethylene, polypropylene, polyethylene terephthalate, or polyvinyl chloride; or paper.

In some examples, the cooling element <NUM> and the filter <NUM> may be held together by a wrapper paper to form an assembly. The assembly may then be joined to the aerosolisable material by a further wrapper which circumscribes the assembly and at least the mouth end of the aerosolisable material to form the aerosol generating article <NUM>. In other examples, the aerosol generating article <NUM> is formed by wrapping the cooling element <NUM>, the filter <NUM> and the aerosolisable material <NUM> effectively in one operation, with no separate tipping paper being provided for the cooling element and/or filter components (if present).

In some cases, one or more ventilation apertures may be formed in the aerosol-generating article. The ventilation apertures may provide airflow into the article during use which forms part of the inhaled aerosol. It may be desirable to reduce airflow over the distal-end of the article to reduce the propensity to burn, and so the apertures may be formed nearer to the mouth-end of the article than to the distal-end. For example, the ventilation apertures may be formed in the cooling element and/or filter, if present. Moreover, the ventilation holes may be formed in a part of the article that is not wrapped in the non-combustible material. The inventors have established that cutting the non-combustible material to form ventilation apertures may not be straightforward.

In use, in some cases, the aerosol generating article may be arranged at least partially within a heating device to form an aerosol generating assembly which heats the article to generate an aerosol without burning. In some other cases, the article may be provided in an assembly with a fuel source, such as a combustible fuel source or chemical heat source, which heats but does not burn the aerosolisable material.

Claim 1:
An aerosol generating article, the aerosol generating article (<NUM>) comprising an aerosolisable material (<NUM>) and a wrapper (<NUM>) wrapped around the aerosolisable material (<NUM>), wherein the wrapper (<NUM>) comprises at least three layers; an innermost peripheral layer (<NUM>) disposed in contact with the aerosolisable material (<NUM>) and an outermost peripheral layer (<NUM>), the innermost and outermost peripheral layers (<NUM>, <NUM>) comprising paper, and an intermediate layer (<NUM>) comprising a non-combustible material, wherein at least the intermediate layer (<NUM>) and one of the innermost or outermost peripheral layers (<NUM>, <NUM>) are provided as a laminate structure, characterised in that the paper of either or each of the innermost and outermost layers (<NUM>, <NUM>) has a basis weight of <NUM> to <NUM>/m<NUM> and in that the wrapper (<NUM>) extends from a distal end of the aerosol generating article (<NUM>).