Patent Description:
Aerosol-generating systems for delivering an aerosol to a user typically comprise an aerosol-generating article and an atomiser. The aerosol-generating article includes an aerosol-forming substrate. The atomiser is configured to generate an inhalable aerosol from an aerosol-forming substrate. Some known aerosol-generating systems comprise a thermal atomiser such as an electric heater or an inductive heating device. The thermal atomiser is configured to heat and vaporise the aerosol-forming substrate to generate an aerosol, which can be inhaled by a user. Typical aerosol-forming substrates for use in aerosol-generating systems are nicotine formulations, which may be liquid nicotine formulations comprising an aerosol former such as glycerine.

It would be desirable to provide an aerosol-generating article that provides improved nicotine delivery.

<CIT> describes a "heated cigarette" comprising an aerosol-forming substrate and a wrapper, wherein the wrapper is wrapped around the aerosol-forming substrate. The article also includes tipping paper, a support section, a cooling section, and a filter. The wrapper comprises a metal layer and a hydrophobic layer, joined together by an adhesive layer. The metal layer is in contact with the aerosol-forming substrate. The thickness of the metal layer is <NUM>-<NUM> micrometres.

<CIT> describes a laminate aerosol generating material, wherein the material comprises an aerosol-forming layer attached to a carrier layer, wherein the aerosol-forming layer comprises an amorphous solid and wherein the carrier comprises wood and/or cardboard.

There is also provided an aerosol-generating article comprising: an aerosol-forming substrate comprising one or more aerosol formers; and a wrapper, wherein the wrapper is wrapped around the aerosol-forming substrate, wherein the wrapper comprises a metal layer, wherein the aerosol-forming substrate has an aerosol former content of greater than or equal to <NUM> percent by weight, wherein the metal layer has a thickness of greater than or equal to <NUM> nanometres, and wherein the metal layer has a thickness of less than <NUM> nanometres.

There is also provided an aerosol-generating system comprising aerosol-generating article, the aerosol-generating article comprising: an aerosol-forming substrate comprising one or more aerosol formers; and a wrapper, wherein the wrapper is wrapped around the aerosol-forming substrate, wherein the wrapper comprises a metal layer, and wherein the aerosol-forming substrate has an aerosol former content of greater than or equal to <NUM> percent by weight, wherein the metal layer has a thickness of greater than or equal to <NUM> nanometres, and wherein the metal layer has a thickness of less than <NUM> nanometres.

The provision of a wrapper wrapped around the aerosol-forming substrate, and including a metal layer, provides better nicotine delivery when the aerosol-forming substrate comprises a high amount of aerosol former.

The inventors believe that the metal layer may form a barrier between a surface or surfaces of the aerosol-forming substrate and the other components of the aerosol-generating article. This barrier may reduce migration of one or more components of the aerosol-forming substrate, such as the aerosol former, out of the aerosol-forming substrate and into the other components of the aerosol-generating article.

The increase in the amount of nicotine delivered from the aerosol-forming substrate may be caused by the barrier reducing the migration of one or more components of the aerosol-forming substrate out of the aerosol-forming substrate.

As used herein, the term "aerosol-generating article" refers to an article for producing an aerosol. An aerosol-generating article typically comprises an aerosol-forming substrate that is suitable and intended to be heated or combusted in order to release volatile compounds that can form 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 an aerosol-forming substrate and not by combusting the aerosol-forming substrate. Known heated aerosol-generating articles include, for example, electrically heated aerosol-generating articles.

As used herein, the term "aerosol-forming substrate" refers to a substrate that is capable of producing upon heating volatile compounds, which can form an aerosol. The aerosol generated from aerosol-forming substrate may be visible to the human eye or invisible and may include vapours (for example, fine particles of substances, which are in a gaseous state, that are ordinarily liquid or solid at room temperature) as well as gases and liquid droplets of condensed vapours.

As used herein with reference to the present invention, the term "susceptor element" refers to a material that can convert electromagnetic energy into heat. When located within a fluctuating electromagnetic field, eddy currents induced in the susceptor element cause heating of the susceptor element. As the susceptor element is located in thermal contact with the aerosol-forming substrate, the aerosol-forming substrate is heated by the susceptor element.

As used herein, the term "paper layer" is used to describe a layer formed from cellulosic fibres.

The paper layer may be a non-metallic layer. In other words, the paper layer is not a metal layer or an alloy layer.

The metal layer may be radially inward of the paper layer.

Alternatively, the metal layer may be radially outward of the paper layer.

The metal layer may be deposited on the paper layer. The metal layer may be formed by physical vapour deposition. Advantageously, depositing the metal layer on the paper layer may allow for the wrapper to be thin. When the aerosol-generating article includes a susceptor, a thin wrapper may result in less interaction with the magnetic field and it may not significantly alter the electromagnetic properties of the aerosol-generating article. In addition, use of a thin metal layer may reduce the amount of metal needed to form the metal layer, which may improve sustainability.

The wrapper may comprise a laminate of the metal layer fixed to the paper layer. The metal layer may be formed by lamination. Advantageously, use of lamination may provide a wrapper that is easier to manufacture. In addition, lamination may result in a more homogenous layer. Moreover, lamination may be a better option than deposition for an aerosol-generating article that is externally heated, due to the better thermo-conductivity of the thicker layers causing increased conduction of heat.

The wrapper may be wrapped around at least <NUM> percent of the entire length of the aerosol-forming substrate. The wrapper may be wrapped around at least <NUM> percent of the entire length of the aerosol-forming substrate. The wrapper may be wrapped around at least <NUM> percent of the entire length of the aerosol-forming substrate. The wrapper may be wrapped around at least <NUM> percent of the entire length of the aerosol-forming substrate.

The aerosol-generating article may comprise a plug containing the aerosol-forming substrate. The plug may be formed from a porous material. The wrapper may be wrapped around the plug.

The aerosol-generating article may comprise a rod of aerosol-forming substrate. The wrapper may be wrapped around the rod.

If the metal layer is too thin then it may not be possible to manufacture the metal layer, and the metal layer may have less anti-capillary properties. However, if the metal layer is too thick then there may be more interaction with a magnetic field when the aerosol-generating article is inductively heated, and the metal layer may be more expensive to manufacture.

The metal layer has a thickness of greater than or equal to <NUM> nanometres. The metal layer may have a thickness of greater than or equal to <NUM> nanometres. The metal layer may have a thickness of greater than or equal to <NUM> nanometres. The metal layer may have a thickness of greater than or equal to <NUM> nanometres. The metal layer may have a thickness of greater than or equal to <NUM> nanometres. The metal layer may have a thickness of greater than or equal to <NUM> nanometres. The metal layer may have a thickness of greater than or equal to <NUM> nanometres. The metal layer may have a thickness of greater than or equal to <NUM> nanometres. The metal layer may have a thickness of greater than or equal to <NUM> nanometres.

The metal layer may have a thickness of less than <NUM> nanometres. The metal layer may have a thickness of less than <NUM> nanometres. The metal layer may have a thickness of less than <NUM> nanometres. The metal layer may have a thickness of less than <NUM> nanometres. The metal layer may have a thickness of less than <NUM> nanometres. The metal layer may have a thickness of less than <NUM> nanometres. The metal layer may have a thickness of less than <NUM> nanometres. The metal layer may have a thickness of less than <NUM> nanometres. The metal layer may have a thickness of less than <NUM> nanometres.

The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres.

The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres.

The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres. The metal layer may have a thickness of between <NUM> nanometres and <NUM> nanometres.

The metal layer may comprise one or more of the following metals: aluminium, chromium, copper, gold, nickel, silver, and tin. The metal layer may be formed from aluminium. The metal layer may comprise an aluminium layer. Advantageously, aluminium has a relatively low boiling point, which may make it easier to form the metal layer, particularly when using vapour deposition. In addition, aluminium has a lower cost when compared to other metals.

If the paper layer is too thin then the paper layer may not provide enough resistance to tearing. If the paper layer is too thick then the wrapper may be too difficult to roll during manufacture, which may reduce the speed of manufacture of the aerosol-generating article.

The paper layer may have a thickness of greater than or equal to <NUM> micrometres. The paper layer may have a thickness of greater than or equal to <NUM> micrometres. The paper layer may have a thickness of greater than or equal to <NUM> micrometres.

The paper layer may have a thickness of less than <NUM> micrometres. The paper layer may have a thickness of less than <NUM> micrometres. The paper layer may have a thickness of less than <NUM> micrometres.

The paper layer may have a thickness of between <NUM> micrometres and <NUM> micrometres. The paper layer may have a thickness of between <NUM> micrometres and <NUM> micrometres. The paper layer may have a thickness of between <NUM> micrometres and <NUM> micrometres.

The paper layer may have a thickness of between <NUM> micrometres and <NUM> micrometres. The paper layer may have a thickness of between <NUM> micrometres and about <NUM> micrometres. The paper layer may have a thickness of between <NUM> micrometres and <NUM> micrometres.

The aerosol-generating article may comprise an upstream element located upstream of the aerosol-forming substrate. The upstream element may be located adjacent to the aerosol-forming substrate.

Advantageously, provision of an upstream element in combination with the metal layer of the wrapper may result in reduced migration of one or more components of the aerosol-forming substrate to other parts of the aerosol-generating article.

The upstream element may comprise a porous element. The porous element may not significantly alter the resistance to draw of the aerosol-generating article.

The upstream element may comprise an annular element.

The wrapper may be wrapped around at least a portion of the upstream element. The wrapper may be wrapped around at least <NUM> percent of the length of the upstream element. The wrapper may be wrapped around at least <NUM> percent of the length of the upstream element. The wrapper may be wrapped around at least <NUM> percent of the length of the upstream element. The wrapper may be wrapped around at least <NUM> percent of the length of the upstream element. The wrapper may be wrapped around at least <NUM> percent of the length of the upstream element. The wrapper may be wrapped around at least <NUM> percent of the length of the upstream element. The wrapper may be wrapped around the entire length of the upstream element.

Advantageously, providing the wrapper over at least a portion of the upstream element may reduce migration of components of the aerosol-forming substrate through the join between the aerosol-forming substrate and the upstream element.

The upstream element may be made of any material suitable for use in an aerosol-generating article. The upstream element may be made of a same material as used for one of the other components of the aerosol-generating article. Suitable materials for forming the upstream element include filter materials, ceramic, polymer material, cellulose acetate, cardboard, zeolite or aerosol-generating substrate. The upstream element may be formed from a plug of cellulose acetate.

The upstream element may be formed of a heat resistant material. For example, the upstream element may be formed of a material that resists temperatures of up to <NUM> degrees Celsius. This may ensure that the upstream element is not adversely affected by the heating means for heating the aerosol-generating substrate.

The upstream element may have a diameter that is approximately equal to the diameter of the aerosol-generating article.

The upstream element may have a length of between <NUM> millimetre and <NUM> millimetres. The upstream element may have a length of between <NUM> millimetres and <NUM> millimetres. The upstream element may have a length of between <NUM> millimetres and <NUM> millimetres.

The upstream element may have a length of <NUM> millimetres.

The length of the upstream element can advantageously be varied in order to provide the desired total length of the aerosol-generating article. For example, where it is desired to reduce the length of one of the other components of the aerosol-generating article, the length of the upstream element may be increased in order to maintain the same overall length of the article.

The aerosol-generating article may comprise a downstream element located downstream of the aerosol-forming substrate. The downstream element may be located adjacent to the aerosol-forming substrate.

Advantageously, provision of an downstream element in combination with the metal layer of the wrapper may result in reduced migration of one or more components of the aerosol-forming substrate to other parts of the aerosol-generating article.

The wrapper may be wrapped around at least a portion of the downstream element. The wrapper may be wrapped around at least <NUM> percent of the length of the downstream element. The wrapper may be wrapped around at least <NUM> percent of the length of the downstream element. The wrapper may be wrapped around at least <NUM> percent of the length of the downstream element. The wrapper may be wrapped around at least <NUM> percent of the length of the downstream element. The wrapper may be wrapped around at least <NUM> percent of the length of the downstream element. The wrapper may be wrapped around at least <NUM> percent of the length of the downstream element. The wrapper may be wrapped around the entire length of the downstream element.

Advantageously, providing the wrapper over at least a portion of the downstream element may reduce migration of components of the aerosol-forming substrate through the join between the aerosol-forming substrate and the downstream element.

The downstream element may be made of any material suitable for use in an aerosol-generating article. The downstream element may be made of a same material as used for one of the other components of the aerosol-generating article. Suitable materials for forming the downstream element include filter materials, ceramic, polymer material, cellulose acetate, cardboard, zeolite or aerosol-generating substrate. The downstream element may be formed from a plug of cellulose acetate.

The downstream element may be formed of a heat resistant material. For example, the upstream element may be formed of a material that resists temperatures of up to <NUM> degrees Celsius. This may ensure that the downstream element is not adversely affected by the heating means for heating the aerosol-generating substrate.

The downstream element may comprise a hollow tubular segment. The hollow tubular segment may also be located adjacent to the aerosol-forming substrate.

The hollow tubular segment may comprise a cellulose acetate tube. The hollow tubular segment may comprise two cellulose acetate tubes.

Advantageously, providing the wrapper over at least a portion of the hollow tubular segment may reduce migration of components of the aerosol-forming substrate through the join between the aerosol-forming substrate and the hollow tubular segment.

The downstream element may be located adjacent to the aerosol-forming substrate.

The downstream element may comprise a hollow tubular segment.

The downstream element may comprise a filter plug element.

The downstream element may comprise a second hollow tubular segment. The second hollow tubular segment may be located adjacent to the hollow tubular segment.

The wrapper may be wrapped around at least a portion of the second hollow tubular segment. The wrapper may be wrapped around at least <NUM> percent of the length of the second hollow tubular segment. The wrapper may be wrapped around at least <NUM> percent of the length of the second hollow tubular segment. The wrapper may be wrapped around at least <NUM> percent of the length of the second hollow tubular segment. The wrapper may be wrapped around at least <NUM> percent of the length of the second hollow tubular segment. The wrapper may be wrapped around at least <NUM> percent of the length of the second hollow tubular segment. The wrapper may be wrapped around at least <NUM> percent of the length of the second hollow tubular segment. The wrapper may be wrapped around the entire length of the second hollow tubular segment.

The downstream element may comprise a mouthpiece element at its downstream end. The mouthpiece element may comprise a mouth end cavity. The mouth end cavity may be defined by a hollow tubular element provided at the downstream end of the mouthpiece element. Alternatively, the mouth end cavity may be defined by the outer wrapper, wherein the outer wrapper extends in a downstream direction from the mouthpiece element.

The wrapper may be wrapped around at least a portion of the mouthpiece element. The wrapper may be wrapped around at least <NUM> percent of the length of the mouthpiece element. The wrapper may be wrapped around at least <NUM> percent of the length of the mouthpiece element. The wrapper may be wrapped around at least <NUM> percent of the length of the mouthpiece element. The wrapper may be wrapped around at least <NUM> percent of the length of the mouthpiece element. The wrapper may be wrapped around at least <NUM> percent of the length of the mouthpiece element. The wrapper may be wrapped around at least <NUM> percent of the length of the mouthpiece element. The wrapper may be wrapped around the entire length of the mouthpiece element.

In an aerosol-generating article, an upstream element, an aerosol-forming substrate, a hollow tubular segment, a second hollow tubular segment and a mouthpiece element may be referred to as elements of the aerosol-generating article.

The wrapper may be wrapped around at least one element of the aerosol-generating article. The wrapper may be wrapped around at least two elements of the aerosol-generating article. The wrapper may be wrapped around at least three elements of the aerosol-generating article. The wrapper may be wrapped around at least four elements of the aerosol-generating article. The wrapper may be wrapped around at least five elements of the aerosol-generating article. The wrapper may be wrapped around all elements of the aerosol-generating article. For example, in an aerosol-generating article comprising an upstream element, an aerosol-forming substrate, a hollow tubular segment, a second hollow tubular segment and a mouthpiece element, wrapper may be wrapped around all of these elements.

The wrapper may be wrapped around at least <NUM> percent of the length of the aerosol-generating article. The wrapper may be wrapped around at least <NUM> percent of the length of the aerosol-generating article. The wrapper may be wrapped around at least <NUM> percent of the length of the aerosol-generating article. The wrapper may be wrapped around at least <NUM> percent of the length of the aerosol-generating article. The wrapper may be wrapped around at least <NUM> percent of the length of the aerosol-generating article. The wrapper may be wrapped around at least <NUM> percent of the length of the aerosol-generating article. The wrapper may be wrapped around at least <NUM> percent of the length of the aerosol-generating article. The wrapper may be wrapped around at least <NUM> percent of the length of the aerosol-generating article. The wrapper may be wrapped around at least <NUM> percent of the length of the aerosol-generating article. The wrapper may be wrapped around at least <NUM> percent of the length of the aerosol-generating article. The wrapper may be wrapped around at least <NUM> percent of the length of the aerosol-generating article. The wrapper may be wrapped around at least <NUM> percent of the length of the aerosol-generating article. The wrapper may be wrapped around at least <NUM> percent of the length of the aerosol-generating article. The wrapper may be wrapped around at least <NUM> percent of the length of the aerosol-generating article. The wrapper may be wrapped around at least <NUM> percent of the length of the aerosol-generating article. The wrapper may be wrapped around <NUM> percent of the length of the aerosol-generating article.

The wrapper may be wrapped around substantially the whole of the length of the aerosol-generating article. The wrapper may be wrapped around the whole of the length of the aerosol-generating article.

One or more elements of the aerosol-generating article may comprise an element wrapper wrapped around substantially the whole length of the element. One or more elements of the aerosol-generating article may comprise an element wrapper wrapped around the whole length of the element.

For example, the aerosol-forming substrate may comprise an element wrapper wrapped around the length of the rod of the aerosol-forming substrate. The upstream element may comprise an element wrapper wrapped around the length of the upstream element. The hollow tubular segment may comprise an element wrapper wrapped around the length of the hollow tubular segment. The second hollow tubular segment may comprise an element wrapper wrapped around the length of the second hollow tubular segment. The mouthpiece element may comprise an element wrapper wrapped around the length of the mouthpiece element.

Preferably, when the wrapper is wrapped around the length of at least two elements of the aerosol-generating article, one or more of the elements comprises an element wrapper.

The element wrapper may comprise a paper layer.

The wrapper may be wrapped around and over the one or more element wrappers.

The aerosol-forming substrate may comprise a gel. The aerosol-forming substrate may comprise a film. The aerosol-forming substrate may comprise crimped tobacco. The aerosol-forming substrate may comprise cut tobacco filler.

The aerosol-forming substrate may comprise a colloid. The colloid may have discontinuous solid particles dispersed in a continuous liquid. The colloid may have discontinuous liquid particles dispersed in a continuous liquid. The colloid may have discontinuous liquid particles dispersed in a continuous solid.

The aerosol-forming substrate may be a solid.

The aerosol-forming substrate may be a film.

As used herein, unless indicated otherwise, the term "percent by weight" refers to dry weight.

The aerosol-forming substrate may have an aerosol former content of greater than <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than or equal to <NUM> percent by weight.

The aerosol-forming substrate may have an aerosol former content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of less than <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of less than <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of less than <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of less than <NUM> percent by weight.

The aerosol-forming substrate may have an aerosol former content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of between <NUM> percent by weight and <NUM> percent by weight.

The aerosol-forming substrate may have an aerosol former content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have an aerosol former content of between <NUM> percent by weight and <NUM> percent by weight.

The aerosol-forming substrate may have an aerosol former content of greater than or equal to <NUM> milligrams. The aerosol-forming substrate may have an aerosol former content of greater than or equal to <NUM> milligrams. The aerosol-forming substrate may have an aerosol former content of greater than or equal to <NUM> milligrams.

The aerosol-forming substrate may have an aerosol former content of less than <NUM> milligrams. The aerosol-forming substrate may have an aerosol former content of less than <NUM> milligrams. The aerosol-forming substrate may have an aerosol former content of less than <NUM> milligrams.

The aerosol-forming substrate may have an aerosol former content of between <NUM> milligrams and <NUM> milligrams. The aerosol-forming substrate may have an aerosol former content of between <NUM> milligrams and <NUM> milligrams. The aerosol-forming substrate may have an aerosol former content of between <NUM> milligrams and <NUM> milligrams. The aerosol-forming substrate may have an aerosol former content of between <NUM> milligrams and <NUM> milligrams.

The aerosol-forming substrate may have an aerosol former content of greater than or equal to <NUM> grams per cubic centimetre. The aerosol-forming substrate may an aerosol former content of greater than or equal to <NUM> grams per cubic centimetre.

The aerosol-forming substrate may have an aerosol former content of less than <NUM> grams per cubic centimetre. The aerosol-forming substrate may have an aerosol former content of less than <NUM> grams per cubic centimetre.

The aerosol-forming substrate may have an aerosol former content of between <NUM> grams per cubic centimetre and <NUM> grams per cubic centimetre. The aerosol-forming substrate may have an aerosol former content of between <NUM> grams per cubic centimetre and <NUM> grams per cubic centimetre.

The one or more aerosol formers may comprise glycerine. The one or more aerosol formers may comprise propylene glycol. The one or more aerosol formers may comprise glycerine and propylene glycol.

The aerosol-forming substrate may comprise water.

The aerosol-forming substrate may have a water content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a water content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a water content of greater than or equal to <NUM> percent by weight.

The aerosol-forming substrate may have a water content of less than <NUM> percent by weight. The aerosol-forming substrate may have a water content of less than <NUM> percent by weight. The aerosol-forming substrate may have a water content of less than <NUM> percent by weight.

The aerosol-forming substrate may have a water content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a water content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a water content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a water content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a water content of between <NUM> percent by weight and <NUM> percent by weight.

The aerosol-forming substrate may comprise nicotine.

The aerosol-forming substrate may have a nicotine content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a nicotine content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a nicotine content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a nicotine content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a nicotine content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a nicotine content of greater than or equal to <NUM> percent by weight.

The aerosol-forming substrate may have a nicotine content of less than <NUM> percent by weight. The aerosol-forming substrate may have a nicotine content of less than <NUM> percent by weight. The aerosol-forming substrate may have a nicotine content of less than <NUM> percent by weight. The aerosol-forming substrate may have a nicotine content of less than <NUM> percent by weight.

The aerosol-forming substrate may have a nicotine content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a nicotine content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a nicotine content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a nicotine content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a nicotine content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a nicotine content of between <NUM> percent by weight and <NUM> percent by weight.

The aerosol-forming substrate may comprise a film-forming agent.

The film-forming agent may be a cellulose-based film-forming agent.

The cellulose-based film-forming agent may be a carboxymethyl cellulose.

The carboxymethyl cellulose may be sodium carboxymethyl cellulose.

The aerosol-forming substrate may have a film-forming agent content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a film-forming agent content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a film-forming agent content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a film-forming agent content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a film-forming agent content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a film-forming agent content of greater than or equal to <NUM> percent by weight.

The aerosol-forming substrate may have a film-forming agent content of less than <NUM> percent by weight. The aerosol-forming substrate may have a film-forming agent content of less than <NUM> percent by weight. The aerosol-forming substrate may have a film-forming agent content of less than <NUM> percent by weight. The aerosol-forming substrate may have a film-forming agent content of less than <NUM> percent by weight.

The aerosol-forming substrate may have a film-forming agent content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a film-forming agent content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a film-forming agent content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a film-forming agent content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a film-forming agent content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a film-forming agent content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a film-forming agent content of between <NUM> percent by weight and <NUM> percent by weight.

The aerosol-forming substrate may have a carboxymethyl cellulose content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a carboxymethyl cellulose content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a carboxymethyl cellulose content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a carboxymethyl cellulose content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a carboxymethyl cellulose content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a carboxymethyl cellulose content of greater than or equal to <NUM> percent by weight.

The aerosol-forming substrate may have a carboxymethyl cellulose content of less than <NUM> percent by weight. The aerosol-forming substrate may have a carboxymethyl cellulose content of less than <NUM> percent by weight. The aerosol-forming substrate may have a carboxymethyl cellulose content of less than <NUM> percent by weight. The aerosol-forming substrate may have a carboxymethyl cellulose content of less than <NUM> percent by weight.

The aerosol-forming substrate may have a carboxymethyl cellulose content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a carboxymethyl cellulose content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a carboxymethyl cellulose content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a carboxymethyl cellulose content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a carboxymethyl cellulose content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a carboxymethyl cellulose content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a carboxymethyl cellulose content of between <NUM> percent by weight and <NUM> percent by weight.

The aerosol-forming substrate may comprise one or more acids.

The one or more acids may be one or more organic acids.

The one or more organic acids may be one or more carboxylic acids.

The one or more carboxylic acids may be lactic acid.

The one or more carboxylic acids may be levulinic acid.

The aerosol-forming substrate may have an acid content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have an acid content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have an acid content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have an acid content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have an acid content of greater than or equal to <NUM> percent by weight.

The aerosol-forming substrate may have an acid content of less than <NUM> percent by weight. The aerosol-forming substrate may have an acid content of less than <NUM> percent by weight. The aerosol-forming substrate may have an acid content of less than <NUM> percent by weight. The aerosol-forming substrate may have an acid content of less than <NUM> percent by weight. The aerosol-forming substrate may have an acid content of less than <NUM> percent by weight.

The aerosol-forming substrate may have an acid content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have an acid content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have an acid content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have an acid content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have an acid content of between <NUM> percent by weight and <NUM> percent by weight.

The aerosol-forming substrate may have a lactic acid content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a lactic acid content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a lactic acid content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may a lactic acid content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a lactic acid content of greater than or equal to <NUM> percent by weight.

The aerosol-forming substrate may have a lactic acid content of less than <NUM> percent by weight. The aerosol-forming substrate may have a lactic acid content of less than <NUM> percent by weight. The aerosol-forming substrate may have a lactic acid content of less than <NUM> percent by weight. The aerosol-forming substrate may have a lactic acid content of less than <NUM> percent by weight. The aerosol-forming substrate may have a lactic acid content of less than <NUM> percent by weight.

The aerosol-forming substrate may have a lactic acid content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a lactic acid content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a lactic acid content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a lactic acid content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a lactic acid content of between <NUM> percent by weight and <NUM> percent by weight.

The aerosol-forming substrate may have a moisture content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a moisture content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a moisture content of greater than or equal to <NUM> percent by weight. The aerosol-forming substrate may have a moisture content of greater than or equal to <NUM> percent by weight.

The aerosol-forming substrate may have a moisture content of less than <NUM> percent by weight. The aerosol-forming substrate may have a moisture content of less than <NUM> percent by weight. The aerosol-forming substrate may have a moisture content of less than <NUM> percent by weight. The aerosol-forming substrate may have a moisture content of less than <NUM> percent by weight.

The aerosol-forming substrate may have a moisture content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a moisture content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a moisture content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a moisture content of between <NUM> percent by weight and <NUM> percent by weight.

The aerosol-forming substrate may have a moisture content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a moisture content of between <NUM> percent by weight and <NUM> percent by weight. The aerosol-forming substrate may have a moisture content of between <NUM> percent by weight and <NUM> percent by weight.

The moisture content is measured as according to the method defined in the description below.

The term "length" denotes the dimension of the aerosol-generating article or a component of the aerosol-generating article in the longitudinal direction.

The aerosol-generating article may have a length of less than <NUM> millimetres. The aerosol-generating article may have a length of less than <NUM> millimetres. The aerosol-generating article may have a length of less than <NUM> millimetres. The aerosol-generating article may have a length of less than <NUM> millimetres. The aerosol-generating article may have a length of less than <NUM> millimetres. The aerosol-generating article may have a length of less than <NUM> millimetres.

The aerosol-generating article may have a length of greater than or equal to <NUM> millimetres. The aerosol-generating article may have a length of greater than or equal to <NUM> millimetres. The aerosol-generating article may have a length of greater than or equal to <NUM> millimetres. The aerosol-generating article may have a length of greater than or equal to <NUM> millimetres. The aerosol-generating article may have a length of greater than or equal to <NUM> millimetres. The aerosol-generating article may have a length of greater than or equal to <NUM> millimetres.

The aerosol-generating article may have a length of between <NUM> millimetres and <NUM> millimetres. The aerosol-generating article may have a length of between <NUM> millimetres and <NUM> millimetres. The aerosol-generating article may have a length of between <NUM> millimetres and <NUM> millimetres.

The aerosol-generating article may have a length of between <NUM> millimetres and <NUM> millimetres. The aerosol-generating article may have a length of between <NUM> millimetres and <NUM> millimetres.

The aerosol-generating article may have a length of <NUM> millimetres.

The aerosol-generating article may have an external diameter of less than <NUM> millimetres. The aerosol-generating article may have an external diameter of less than <NUM> millimetres. The aerosol-generating article may have an external diameter of less than <NUM> millimetres. The aerosol-generating article may have an external diameter of less than <NUM> millimetres.

The aerosol-generating article may have an external diameter of greater than or equal to <NUM> millimetres. The aerosol-generating article may have an external diameter of greater than or equal to <NUM> millimetres. The aerosol-generating article may have an external diameter of greater than or equal to <NUM> millimetres.

The aerosol-generating article may have an external diameter of between <NUM> millimetres and <NUM> millimetres. The aerosol-generating article may have an external diameter of between <NUM> millimetres and <NUM> millimetres. The aerosol-generating article may have an external diameter of between <NUM> millimetres and <NUM> millimetres.

The aerosol-generating article may comprise an outermost wrapper wrapped around at least the aerosol-forming substrate and the wrapper.

The outermost wrapper may be formed from paper.

The aerosol-generating article may comprise a susceptor element. The aerosol-generating article may comprise a plurality of susceptor elements.

The susceptor element may be an elongate susceptor element. The susceptor element may be rod-shaped. The susceptor element may be flat. Preferably, the susceptor element has a length of <NUM>. Preferably, the susceptor element has a width of <NUM>. Preferably, the susceptor element has a thickness of <NUM>.

When used for describing the susceptor element, the term "elongate" means that the susceptor element has a length dimension that is greater than its width dimension or its thickness dimension. For example, the length dimension may be greater than twice the width dimension or the thickness dimension.

The susceptor element may be arranged substantially longitudinally within the aerosol-generating article. This means that the length dimension of the susceptor element is arranged to be approximately parallel to the longitudinal direction of the aerosol-generating article. For example, the susceptor element may be arranged to be within plus or minus <NUM> degrees of parallel to the longitudinal direction of the aerosol-generating article. The susceptor element may be positioned in a radially central position within the aerosol-generating article. The susceptor element may extend along the longitudinal axis of the rod.

The susceptor element may be provided within the aerosol-forming substrate. The susceptor element may extend the entire length of the aerosol-forming substrate.

The susceptor element may be a plurality of susceptor particles which may be deposited on or embedded within the aerosol-forming substrate. The susceptor particles may be immobilized by the aerosol-forming substrate and remain at an initial position. The susceptor particles may be homogeneously distributed in the aerosol- forming substrate. Due to the particulate nature of the susceptor, heat may be produced according to the distribution of the particles in the aerosol-forming substrate. Alternatively, the susceptor element may be in the form of one or more sheets, strips, shreds or rods that may be placed next to or embedded in the aerosol-forming substrate. The aerosol-forming substrate may comprise one or more susceptor strips.

As used herein, the term "thickness" refers to the distance through the susceptor, from one external face to another external face. The susceptor element may have a thickness of between <NUM> millimetre and <NUM> millimetres. The susceptor element may have a thickness of between <NUM> millimetres and <NUM> millimetres. The susceptor element may have a thickness of between <NUM> millimetres and <NUM> millimetres. The susceptor element may have a thickness of between <NUM> micrometres and <NUM> micrometres. The susceptor element may have a thickness of between <NUM> micrometres and <NUM> micrometres.

The susceptor may have a constant cross- section. The susceptor element may have a circular cross-section. If the susceptor element has a circular cross-section, the susceptor element may have a diameter of between <NUM> millimetre and <NUM> millimetres. The diameter of a susceptor with a non-circular cross-section, such as a flat susceptor, may be equivalent to the thickness of the flat susceptor.

The susceptor element may have a diameter of less than <NUM> millimetres. The susceptor element may have a diameter of less than <NUM> millimetres. The susceptor element may have a diameter of less than <NUM> millimetres. The susceptor element may have a diameter of less than <NUM> millimetres.

The susceptor element may have a diameter of greater than or equal to <NUM> millimetre. The susceptor element may have a diameter of greater than or equal to <NUM> millimetres. The susceptor element may have a diameter of greater than or equal to <NUM> millimetres The susceptor element may have a diameter of greater than or equal to <NUM> millimetres.

For example, when the susceptor element has a circular cross-section, the width of the susceptor element may be the same as the diameter of the susceptor element.

A ratio of the thickness of the susceptor element to the thickness of the metal layer may be less than <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be less than <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be less than <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be less than <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be less than <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be less than <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be less than <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be less than <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be less than <NUM>.

A ratio of the thickness of the susceptor element to the thickness of the metal layer may be greater than or equal to <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be greater than or equal to <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be greater than or equal to <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be greater than or equal to <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be greater than or equal to <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be greater than or equal to <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be greater than or equal to <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be greater than or equal to <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be greater than or equal to <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be between <NUM> and <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be between <NUM> and <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be between <NUM> and <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be between <NUM> and <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be between <NUM> and <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be between <NUM> and <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be between <NUM> and <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be between <NUM> and <NUM>. A ratio of the thickness of the susceptor element to the thickness of the metal layer may be between <NUM> and <NUM>.

The total exposed surface area of the aerosol-forming substrate may be maximised by increasing the bulk density of the aerosol-forming substrate so that a greater amount of the substrate, and therefore potentially a larger exposed surface area, can be provided per unit volume of the plug of aerosol-forming substrate. The efficiency of release of aerosol from a given volume of aerosol-forming substrate can thereby be improved.

Mitigating migration of components away from an aerosol-forming substrate may be particularly important when the bulk density is high because the aerosol-forming substrate has move contact with the wrapper.

The bulk density of the aerosol-forming substrate may be greater than or equal to <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be greater than or equal to <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be greater than or equal to <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be greater than or equal to <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be greater than or equal to <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be greater than or equal to <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be greater than or equal to <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be greater than or equal to <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be greater than or equal to <NUM> milligrams per cubic centimetre of the aerosol-forming substrate.

The bulk density of the aerosol-forming substrate may be less than <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be less than <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be less than <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be less than <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be less than <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be less than <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may less than <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be less than <NUM> milligrams per cubic centimetre of the aerosol-forming substrate.

The bulk density of the aerosol-forming substrate may be between <NUM> milligrams per cubic centimetre of the aerosol-forming substrate and <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be between <NUM> milligrams per cubic centimetre of the aerosol-forming substrate and <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be between <NUM> milligrams per cubic centimetre of the aerosol-forming substrate and <NUM> milligrams per cubic centimetre of the aerosol-forming substrate. The bulk density of the aerosol-forming substrate may be between <NUM> milligrams per cubic centimetre of the aerosol-forming substrate and <NUM> milligrams per cubic centimetre of the aerosol-forming substrate.

The bulk density of the aerosol-forming substrate corresponds to the total weight of the aerosol-forming substrate (in milligrams), not including the weight of any carrier material, divided by the total volume of the aerosol-forming substrate (in cubic centimetres).

The aerosol-generating system may include an aerosol-generating device.

The aerosol-generating device may comprise a housing defining a device cavity configured to receive at least a portion of the aerosol-generating article.

The aerosol-generating device may comprise an atomiser configured to generate an aerosol from the aerosol-forming substrate.

As used herein, the term "thermal atomiser" describes an atomiser that is configured to heat the aerosol-forming substrate to generate an aerosol.

The aerosol-generating device may comprise any suitable type of thermal atomiser. For example, the thermal atomiser may comprise a heater. The thermal atomiser may comprise an electric heater. In one example, the thermal atomiser may comprise an electric heater comprising a heating element. The heating element may be a resistive heating element. In one example, the heating element may comprise a heater blade or pin adapted to be inserted into the aerosol-forming substrate so that the aerosol-forming substrate is heated from its inside. In another example, the heating element may partially or completely surround the aerosol-forming substrate and heat the aerosol-forming substrate circumferentially from its outside.

In another example, the thermal atomiser may comprise an inductive heating device. Inductive heating devices typically comprise an induction source that is configured to be coupled to a susceptor element, which may be provided externally to the aerosol-forming substrate or internally within the aerosol-forming substrate. The induction source generates an alternating electromagnetic field that induces magnetization or eddy currents in the susceptor element. The susceptor element may be heated as a result of hysteresis losses or induced eddy currents which heat the susceptor element through ohmic or resistive heating.

The aerosol-generating device may include a susceptor. The susceptor element may be as described above in relation to the aerosol-generating article.

An aerosol-generating device comprising an inductive heating device may be configured to receive an aerosol-generating article having the aerosol-forming substrate and a susceptor element in thermal proximity to the aerosol-forming substrate. Typically, the susceptor element is in direct contact with the aerosol-forming substrate and heat is transferred from the susceptor element to the aerosol-forming substrate primarily by conduction.

Examples of electrically operated aerosol-generating systems having inductive heating devices and aerosol-generating articles having susceptor elements are described in <CIT> and <CIT>.

The aerosol-generating device may comprise a battery and control electronics.

It will be appreciated that any features described herein in relation to one embodiment of an aerosol-forming substrate, an aerosol-generating article, an aerosol-generating device, or an aerosol-generating system may also be applicable to other embodiments of aerosol-forming substrates, an aerosol-generating articles, an aerosol-generating devices, or aerosol-generating systems according to this disclosure. A feature described in relation to one embodiment may be equally applicable to another embodiment in accordance with this disclosure. It will also be appreciated that an aerosol generator according to this disclosure may be provided in an aerosol-generating device without a cartridge. Accordingly, any of the features described herein with relation to a cartridge may be equally applicable to an aerosol-generating device.

The invention will be further described with reference to the drawings shown in the accompanying Figures, in which:.

The aerosol-forming substrate is typically held within a plug of a porous material. It has been found that, in some cases, a quantity of one or more components of the aerosol-forming substrate, such as glycerine or nicotine, may leak out of the plug and migrate to other parts of the aerosol-generating article. Migration of the aerosol-forming substrate away from the plug may reduce the amount of aerosol-forming substrate that can be vaporised and then inhaled by a user.

Accordingly, migration of a components of the aerosol-forming substrate away from the plug may have a negative impact of the user experience provided by the aerosol-generating article. For example, migration of nicotine from the aerosol-forming substrate may reduce the amount of nicotine that can be inhaled by a user.

It has been found that migration of components of the aerosol-forming substrate away from the plug is particularly a problem for aerosol-forming substrates having significant quantities of aerosol-former, such as an aerosol former content of greater than <NUM> percent by weight. This may be because an increased proportion of glycerine in the aerosol-forming substrate provides a more fluid aerosol-forming substrate, which is more liable to leak.

One known solution is to wrap the aerosol-generating article in hydrophobic paper. However, the present inventors have found that when using hydrophobic paper, some of the aerosol former in the aerosol-forming substrate may migrate into the paper during the process of manufacturing the aerosol-generating article. This can dampen or soften the hydrophobic paper, which may make the aerosol-generating article difficult to handle, or may result in the aerosol-generating becoming jammed in a machine used for manufacturing the aerosol-generating article.

It would be desirable to provide an aerosol-generating article that has a reduced likelihood of a component of the aerosol-forming substrate migrating from the aerosol-forming substrate to another part of the aerosol-generating article.

<FIG> shows an example of an aerosol-generating article <NUM>.

The aerosol-generating article <NUM> includes a rod <NUM> of aerosol-forming substrate. In this example, the rod <NUM> of aerosol-forming substrate is formed by crimping a portion of a sheet of cast leaf tobacco.

The aerosol-generating article <NUM> also includes a downstream section <NUM> and an upstream section <NUM>. The downstream section <NUM> is at a location downstream of the rod <NUM> of aerosol-forming substrate. The upstream section <NUM> is at a location upstream of the rod <NUM> of aerosol-forming substrate. In this example, the aerosol-generating article <NUM> extends from an upstream end (or distal end) <NUM> to a downstream end (or mouth end) <NUM>.

In the example shown in <FIG>, the aerosol-generating article <NUM> has an overall length of about <NUM> millimetres.

The downstream section <NUM> includes a support element <NUM> located immediately downstream of the rod <NUM> of aerosol-forming substrate. The support element <NUM> is in longitudinal alignment with the rod <NUM> of aerosol-forming substrate.

In the example shown in <FIG>, the upstream end of the support element <NUM> abuts the downstream end of the rod <NUM> of aerosol-forming substrate.

The downstream section <NUM> includes an aerosol-cooling element <NUM>. The aerosol-cooling element <NUM> is located immediately downstream of the support element <NUM>. The aerosol-cooling element <NUM> is in longitudinal alignment with the rod <NUM> of aerosol-forming substrate and the support element <NUM>. In the example shown in <FIG>, an upstream end of the aerosol-cooling element <NUM> abuts a downstream end of the support element <NUM>.

The support element <NUM> and the aerosol-cooling element <NUM> together define an intermediate hollow section <NUM> of the aerosol-generating article <NUM>.

The support element <NUM> includes a first hollow tubular segment <NUM>. In the example of <FIG>, the first hollow tubular segment <NUM> is provided in the form of a hollow cylindrical tube made of cellulose acetate. The first hollow tubular segment <NUM> defines an internal cavity <NUM> that extends all the way from an upstream end <NUM> of the first hollow tubular segment <NUM> to a downstream end <NUM> of the first hollow tubular segment <NUM>. The internal cavity <NUM> is substantially empty, and so substantially unrestricted airflow is enabled along the internal cavity <NUM>.

In the example shown in <FIG>, the first hollow tubular segment <NUM> has a length of about <NUM> millimetres, an external diameter of about <NUM> millimetres, and an internal diameter of about <NUM> millimetres. Thus, a thickness of a peripheral wall of the first hollow tubular segment <NUM> is about <NUM> millimetres.

The aerosol-cooling element <NUM> includes a second hollow tubular segment <NUM>. In the example of <FIG>, the second hollow tubular segment <NUM> is provided in the form of a hollow cylindrical tube made of cellulose acetate. The second hollow tubular segment <NUM> defines an internal cavity <NUM> that extends all the way from an upstream end <NUM> of the second hollow tubular segment to a downstream end <NUM> of the second hollow tubular segment <NUM>. The internal cavity <NUM> is substantially empty, and so substantially unrestricted airflow is enabled along the internal cavity <NUM>.

In the example shown in <FIG>, the second hollow tubular segment <NUM> has a length of about <NUM> millimetres, an external diameter of about <NUM> millimetres, and an internal diameter of about <NUM> millimetres. Thus, a thickness of a peripheral wall of the second hollow tubular segment <NUM> is about <NUM> millimetres. Thus, a ratio between the internal diameter of the first hollow tubular segment <NUM> and the internal diameter of the second hollow tubular segment <NUM> is about <NUM>.

The aerosol-generating article <NUM> has a ventilation zone <NUM> provided at a location along the second hollow tubular segment <NUM>. In the example of <FIG>, the ventilation zone <NUM> is provided at about <NUM> millimetres from the upstream end of the second hollow tubular segment <NUM>. A ventilation level of the aerosol-generating article <NUM> is about <NUM> percent.

The downstream section <NUM> includes a mouthpiece element <NUM> at a location downstream of the intermediate hollow section <NUM>. The mouthpiece element <NUM> is positioned immediately downstream of the aerosol-cooling element <NUM>. As shown in the drawing of <FIG>, an upstream end of the mouthpiece element <NUM> abuts the downstream end <NUM> of the aerosol-cooling element <NUM>.

In the example of <FIG>, the mouthpiece element <NUM> is provided in the form of a cylindrical plug of low-density cellulose acetate. The mouthpiece element <NUM> has a length of about <NUM> millimetres and an external diameter of about <NUM> millimetres.

In the example of <FIG>, the rod <NUM> of aerosol-forming substrate has an external diameter of about <NUM> millimetres and a length of about <NUM> millimetres.

The aerosol-generating article <NUM> includes an elongate susceptor element <NUM> within the rod <NUM> of aerosol-forming substrate. The susceptor element <NUM> is arranged substantially longitudinally within the aerosol-generating substrate, such as to be approximately parallel to the longitudinal direction of the rod <NUM> of aerosol-forming substrate. The susceptor element <NUM> is positioned in a radially central position within the rod <NUM> and extends effectively along the longitudinal axis of the rod <NUM>.

The susceptor element <NUM> extends all the way from an upstream end to a downstream end of the rod <NUM> of aerosol-forming substrate. In effect, the susceptor element <NUM> has substantially the same length as the rod <NUM> of aerosol-forming substrate.

In the example of <FIG>, the susceptor element <NUM> is provided in the form of a strip and has a length of about <NUM> millimetres, a thickness of about <NUM> micrometres, and a width of about <NUM> millimetres.

The upstream section <NUM> includes an upstream element <NUM>. The upstream element <NUM> is located immediately upstream of the rod <NUM> of aerosol-forming substrate. The upstream element <NUM> is in longitudinal alignment with the rod <NUM>.

The downstream end of the upstream element <NUM> abuts the upstream end of the rod <NUM> of aerosol-forming substrate. Advantageously, this may prevent the susceptor element <NUM> from being dislodged. Further, this may ensure that the user cannot accidentally contact the heated susceptor element <NUM> after use.

In the example of <FIG>, the upstream element <NUM> is provided in the form of a cylindrical plug of cellulose acetate. The upstream element <NUM> has a length of about <NUM> millimetres.

The aerosol-generating article <NUM> includes a wrapper <NUM>. The wrapper <NUM> is wrapped around the rod <NUM> of aerosol-forming substrate. The wrapper <NUM> includes a metal layer. In the example of <FIG>, the metal is aluminium. In the example of <FIG>, the wrapper <NUM> also includes a paper layer. In one example, the metal layer is deposited on the paper layer. For example, the metal layer may be deposited on the paper layer by use of vapour deposition. In another example, the metal layer is fixed to the paper layer. For example, the metal layer and the paper layer may be bonded together to form a laminate.

In the example of <FIG>, the metal layer has a thickness of <NUM> nanometres, and the paper layer has a thickness of <NUM> micrometres.

In some examples, the wrapper <NUM> is wrapped around the entire of the circumferential surface area of the rod <NUM> of aerosol-forming substrate.

The wrapper <NUM> is provided to act as a physical barrier between the rod <NUM> of aerosol-forming substrate and other components of the aerosol-generating article <NUM>.

The aerosol-generating article <NUM> includes an outermost wrapper <NUM>. In the example of <FIG>, the outermost wrapper <NUM> is wrapped around all of the components of the aerosol-generating article <NUM>. The outermost wrapper <NUM> is also wrapper around the wrapper <NUM>.

<FIG>, <FIG>, <FIG>, <FIG> and <FIG> show alternative examples to the example shown in <FIG>. The aerosol-generating article <NUM> of <FIG>, the aerosol-generating article <NUM> of <FIG>, the aerosol-generating article <NUM> of <FIG>, the aerosol-generating article <NUM> of <FIG>, and the aerosol-generating article <NUM> of <FIG> are the same as the aerosol-generating article <NUM> of <FIG> except for the following differences.

In the example shown in <FIG>, the wrapper <NUM> is wrapped around both the rod <NUM> of aerosol-forming substrate and the upstream element <NUM>. In contrast, in the example shown in <FIG>, the wrapper <NUM> is only wrapped around the rod <NUM> of aerosol-forming substrate.

In the example of <FIG>, the wrapper <NUM> is wrapped around the entire length of the upstream element <NUM>. However, in some examples, the wrapper <NUM> may only be wrapped around part of the length of the upstream element <NUM>.

In the example of <FIG>, the upstream element <NUM> is pre-wrapped with a paper element wrapper (not shown), which is positioned underneath the wrapper <NUM>.

In the example shown in <FIG>, the wrapper <NUM> is wrapped around both the rod <NUM> of aerosol-forming substrate and the first hollow tubular segment <NUM>. In contrast, in the example shown in <FIG>, the wrapper <NUM> is only wrapped around the rod <NUM> of aerosol-forming substrate.

In the example of <FIG>, the wrapper <NUM> is wrapped around the entire length of the first hollow tubular segment <NUM>. However, in some examples, the wrapper <NUM> may only be wrapped around part of the length of the first hollow tubular segment <NUM>.

In the example shown in <FIG>, the wrapper <NUM> is wrapped around the entire length of the upstream element <NUM>, the rod <NUM> of aerosol-forming substrate and the first hollow tubular segment <NUM>. In contrast, in the example shown in <FIG>, the wrapper <NUM> is only wrapped around the rod <NUM> of aerosol-forming substrate.

In the example shown in <FIG>, the wrapper <NUM> is wrapped around the entire length of the upstream element <NUM>, the rod <NUM> of aerosol-forming substrate, the first hollow tubular segment <NUM> and the second hollow tubular segment <NUM>. In contrast, in the example shown in <FIG>, the wrapper <NUM> is only wrapped around the rod <NUM> of aerosol-forming substrate.

In the example of <FIG>, the wrapper <NUM> is wrapped around the entire length of the first hollow tubular segment <NUM> and the entire length of the second hollow tubular segment <NUM>. However, in some examples, the wrapper <NUM> may only be wrapped around part of the length of the first hollow tubular segment <NUM> and/or part of the length of the second hollow tubular segment <NUM>.

In the example shown in <FIG>, the wrapper <NUM> is wrapped around the entire length of all elements of the aerosol-generating article <NUM>. In other words, in the example of <FIG>, the wrapper <NUM> is wrapped around the upstream element <NUM>, the rod <NUM> of aerosol-forming substrate, the first hollow tubular segment <NUM>, the second hollow tubular segment <NUM>, and the mouthpiece element <NUM>. In contrast, in the example shown in <FIG>, the wrapper <NUM> is only wrapped around the rod <NUM> of aerosol-forming substrate.

In the examples of <FIG>, <FIG>, <FIG>, <FIG>, <FIG> and <FIG>, the rod <NUM> is a porous medium loaded with an amount of aerosol-forming substrate. An example formulation of a suitable aerosol-forming substrate is shown in Table <NUM>.

The moisture content of Example A is <NUM> percent by weight. In this example, the moisture content includes all the glycerine content and the water content of the formulation.

The moisture content of an aerosol-forming substrate is measured according to the following method:.

From this method, the moisture content in weight % of the aerosol-forming substrate can be obtained.

The provision of a wrapper <NUM> that is wrapped around the rod <NUM> of aerosol-forming substrate, and includes a metal layer, may help to contain one or more of the components of the aerosol-forming substrate within the rod <NUM>. In other words, the wrapper <NUM> may help to reduce migration of one or more components of an aerosol-forming substrate away from the rod <NUM> and into other parts of the aerosol-generating article <NUM>.

Table <NUM> shows the nicotine yield from a rod <NUM> of the aerosol-forming substrate of Example A within the aerosol-generating articles of Example <NUM> and Example <NUM>.

The aerosol-generating article of Example <NUM> is a typical aerosol-generating article that does not include a wrapper with a metal layer wrapped around the aerosol-forming substrate. Instead, the wrapper in the aerosol-generating article of Example <NUM> is a simple paper wrapper. The aerosol-generating article of Example <NUM> is the aerosol-generating article <NUM> as described above and as shown in <FIG>.

As is shown in Table <NUM>, the nicotine yield from the plug <NUM> of aerosol-forming substrate is <NUM> micrograms when the aerosol-generating article <NUM> does not include the wrapper <NUM>. However, when the aerosol-generating article <NUM> does include the wrapper <NUM>, the nicotine yield from the rod <NUM> of aerosol-forming substrate increases by <NUM>% to <NUM> micrograms.

Accordingly, the provision of a wrapper <NUM> that is wrapped around the rod <NUM> of aerosol-forming substrate, and includes a metal layer, increases the nicotine yield from the rod <NUM> of aerosol-forming substrate.

The increase in nicotine yield is because the metal layer of the wrapper may prevent or at least reduce the migration of components of the aerosol-forming substrate, such as the aerosol-former, out of the rod <NUM> and into other parts of the aerosol-generating article <NUM>. It follows that if more of the aerosol-forming substrate is retained within in the rod <NUM> then it is possible to yield more nicotine from the aerosol-forming substrate.

Claim 1:
An aerosol-generating article (<NUM>) comprising:
an aerosol-forming substrate comprising one or more aerosol formers; and
a wrapper (<NUM>),
wherein the wrapper (<NUM>) is wrapped around the aerosol-forming substrate,
wherein the wrapper (<NUM>) comprises a metal layer,
wherein the aerosol-forming substrate has an aerosol former content of greater than or equal to <NUM> percent by weight,
wherein the metal layer has a thickness of greater than or equal to <NUM> nanometres, and
wherein the metal layer has a thickness of less than <NUM> nanometres.