RU2777585C2 - Aerosol generating product with thermally expandable centering element - Google Patents

Abstract

FIELD: tobacco industry.

SUBSTANCE: group of inventions relates to an aerosol generating product and an aerosol generating system. The aerosol generating product contains a rod of aerosol generating substrate, wrapper surrounding at least the rod, and at least one thermally expandable element located on the outer side of wrapper.

EFFECT: maintenance of a product in the required centered position inside a heating chamber is provided, which provides heat supply to aerosol generating substrate, as uniform as possible, during the use, as well as purification of the surface of the heating chamber between uses is provided.

15 cl, 3 dwg

Description

The present invention relates to an aerosol generating article comprising an aerosol generating substrate.

Aerosol-generating articles are known in the art in which the aerosol-generating substrate, such as a tobacco-containing substrate, is heated rather than burned. Typically, in such heated aerosol generating articles, the aerosol is generated by transferring heat from a heat source to a physically separate aerosol generating substrate or material that may be located in contact with, within, around, or downstream of the heat source. During use of the aerosol-generating article, volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source and are entrained in air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol.

Several alternative methods are available for preparing substrates for heated aerosol generating articles, for example from randomly oriented cut pieces, strands or strips of tobacco material. Recently, WO-A-2012/164009 has disclosed rods for heated aerosol generating articles formed from assembled sheets of homogenized tobacco material that allow for improved control of porosity along the rods.

A number of prior art documents disclose aerosol generating devices for consuming aerosol generating articles. Such devices include, for example, electrically heated aerosol generating devices in which the aerosol is generated by transferring heat from one or more electrical heater elements of the aerosol generating device to the aerosol generating substrate of the heated aerosol generating article. The aerosol generating device may, for example, comprise a heating chamber adapted to releasably receive an aerosol generating substrate that can be inserted by the user and removed by the user after use. Thus, in such devices, the aerosol generating substrate can receive heat from the surrounding surface of the heating chamber.

To facilitate insertion and removal of the aerosol generating article, the inner diameter of the heating chamber is preferably larger than the outer diameter of the aerosol generating article. It is also desirable that it allows for possible small changes in the outer diameter of the aerosol generating article. On the contrary, if the inner diameter of the heating chamber is very similar to the outer diameter of the aerosol generating article, fluctuations in the outer diameter of the aerosol generating article may prevent it from being inserted into the device, and, in general, parts of the aerosol generating article may be in direct contact with surfaces heating or even being pressed against them, which may cause localized overheating or even combustion of the aerosol-generating article.

In addition, it has been found that, in general, less aerosol generating substrate is needed in heated aerosol generating articles compared to aerosol generating articles in which the substrate is combusted, such as conventional filter cigarettes. Thus, aerosol generating articles for producing an inhalable aerosol when heated can have a diameter similar to that of a conventional filter cigarette while being shorter than a conventional filter cigarette. Alternatively, aerosol generating articles for producing an inhalable aerosol when heated can be approximately the same length as a conventional filter cigarette while being thinner than a conventional filter cigarette.

Aerosol-generating articles of a narrower type can be quickly heated because the amount of material to be heated per unit length is less. In addition, it may be possible to sequentially independently heat different longitudinal portions of the aerosol generating substrate, which can provide precise control over how the aerosol generating substrate is consumed over time.

However, thinner aerosol generating articles are less suitable for use with an internal heating mechanism, which is a mechanism in which a heating element, such as a heating plate, is inserted into the aerosol generating substrate. This is because inserting a heating element inside an aerosol generating substrate may damage the substrate or the heating element itself.

However, when used in a device containing a heating chamber adapted to receive an aerosol generating article, thinner aerosol generating articles are more prone to slip out of the heating chamber and generally are not held in a perfectly centered position within the heating chamber, and therefore the heat supply energy to the aerosol generating substrate may not be as uniform as possible.

It would be desirable to provide an alternative aerosol generating article that is easier to hold in the correct position during use, while also being easy to insert into the heating chamber of the aerosol generating device. In addition, it would be desirable to provide one such aerosol generating article that can be conveniently manufactured at high speed without requiring any major modification to the existing apparatus.

According to an aspect of the present invention, an aerosol generating article is provided for producing an inhalable aerosol when heated. An aerosol generating article comprises an aerosol generating substrate rod; a wrapper surrounding at least the rod; and at least one thermally expandable element located on the outer surface of the wrapper.

According to another aspect of the present invention, an aerosol generating system is provided, comprising an aerosol generating aerosol product and an electrical aerosol generating device, the aerosol generating device comprising a heater and an elongated heating chamber configured to accommodate the aerosol generating product, such so that the aerosol generating article is heated in the heating chamber. An aerosol generating article comprises an aerosol generating substrate rod; a wrapper surrounding at least the rod, wherein the outer diameter of the surrounded rod is less than the inner diameter of the heating chamber; and at least one thermally expandable element located on the outer surface of the wrapper. The thermally expandable element is configured to deform when heated in the heating chamber in such a way that at least a portion of the thermally expandable element is in contact with the inner surface of the heating chamber.

It should be understood that any features described with reference to one aspect of the present invention are equally applicable to any other aspect of the present invention.

The term "aerosol generating article" is used herein to refer to both articles in which the aerosol generating substrate is heated and articles in which the aerosol generating substrate is burned, such as conventional cigarettes. In the context of this document, the term "aerosol generating substrate" means a substrate capable of releasing volatile compounds when heated to generate an aerosol.

In aerosol-generating heated articles, the aerosol is generated by heating without burning a flavor-generating substrate such as tobacco. Known heated aerosol generating articles include, for example, electrically heated aerosol generating articles and aerosol generating articles in which an aerosol is generated by transferring heat from a combustible fuel element or heat source to a physically separate aerosol generating material. For example, the aerosol generating articles of the present invention find particular use in aerosol generating systems comprising a device that includes a heating chamber adapted to receive at least a portion of the aerosol generating substrate rod. In the context of this document, the term "aerosol generating device" refers to a device containing a heater element that interacts with an aerosol generating substrate of an aerosol generating article to generate an aerosol.

As used herein, the terms "upstream" and "upstream" describe the relative positions of elements or parts of elements of an aerosol generating article with respect to the direction in which the aerosol is transported during use through the aerosol generating article.

In the context of this document, the term "longitudinal" refers to the direction corresponding to the main longitudinal axis of the aerosol generating article, which extends between the ends of the aerosol generating article, upstream and downstream. During use, air is drawn through the aerosol generating article in the longitudinal direction. The term "transverse" refers to a direction that is perpendicular to the longitudinal axis. Any reference to a "section" of an aerosol generating article or a component of an aerosol generating article refers to the cross section unless otherwise indicated.

The term "length" denotes the dimension of the aerosol-generating article component in the longitudinal direction. For example, it can be used to indicate the size of a rod or elongated tubular elements in the longitudinal direction.

In the context of the present invention, the term "thermally expandable" is used to describe a material or component that increases in length, surface area, and volume in response to a change in temperature. In general, the "coefficient of thermal expansion" describes how the size of an object made from a particular material changes with temperature. In other words, the coefficient of thermal expansion is a measure of the relative change in size per degree change in temperature at constant pressure. Reference can be made to several types of coefficients of thermal expansion: volumetric, areal, and linear. Volumetric, areal and linear thermal expansions are closely related.

In the context of this document, the term "inflatable material" is used to describe a material that expands under the influence of elevated temperatures, not only due to its coefficient of thermal expansion. As an example, upon reaching a predetermined temperature, an intumescent material may swell significantly and rapidly due to a chemical process initiated by heat.

As briefly described above, the aerosol generating article of the present invention comprises an aerosol generating substrate rod adapted to release an inhalable aerosol when heated. In addition, the aerosol generating article includes a wrapper surrounding at least the rod. Unlike existing aerosol generating articles, in accordance with the present invention, at least one thermally expandable element is located on the outer surface of the wrapper.

Thus, when the aerosol generating article is exposed to heat during use, in particular when the aerosol generating article is used in an aerosol generating device of the type comprising a heating chamber adapted to at least accommodate the aerosol generating article, thermally the expandable element undergoes volume expansion. Accordingly, the outer diameter of the thermally expandable member is increased, and thus the aerosol generating article can come into contact with the inner surface of the heating chamber.

Advantageously, it is easy to ensure that the aerosol generating article according to the present invention is held stably inside the heating chamber of one such aerosol generating device. In addition, it is easy to ensure that during use the aerosol generating article according to the present invention is maintained in the desired centered position within the heating chamber, which ensures that heat is supplied to the aerosol generating substrate as evenly as possible during use.

In addition, since the thermally expandable member fully contacts the inner surface of the heating chamber when the aerosol generating article is removed from the heating chamber after use, the expanded member can advantageously assist in cleaning the surface of the heating chamber between uses.

At the same time, due to contact with the inner surface of the heating chamber, the expanded element at least partially blocks the gap otherwise provided between the aerosol generating article and the inner surface of the heating chamber. Thus, the air flowing within such a gap cannot be efficiently drawn out by the user towards the mouth end of the aerosol generating device. This is advantageous because, upon direct contact with the heated inner surface of the chamber, this air can become very hot and potentially harm the user during use.

Additionally, the aerosol generating articles of the present invention can advantageously be made in a continuous process that can be efficiently carried out at high speed and can be conveniently incorporated into existing production lines for making heated smoking articles.

As briefly described above, an aerosol generating article according to the present invention comprises an aerosol generating substrate rod and a wrapper surrounding at least the rod. In some embodiments, the wrapper surrounds only the stem. In other embodiments in which the aerosol generating article comprises one or more additional components substantially aligned with the rod, the wrapper may also at least partially surround the one or more additional components.

In the context of this document, the term "rod" is used to refer to a generally cylindrical element with a substantially circular, oval or elliptical cross section.

The aerosol generating substrate may be formed from cut pieces, strands or strips of tobacco material, including sheets of reconstituted tobacco or homogenized tobacco. In the context of this document, the term "homogenized tobacco material" includes any tobacco material formed by agglomeration of particles of tobacco material. Sheets or webs of homogenized tobacco material are formed by agglomerating bulk tobacco material obtained by grinding or otherwise powdering one or both of the leaf tobacco lamella and the leaf tobacco stem. The further homogenized tobacco material may contain one or more of tobacco dust, tobacco fines, and other bulk tobacco by-products generated during the processing, processing, and transport of tobacco, as well as binders, aerosolizers, flavors, other non-tobacco materials such as others. plant materials, including fibers and more. Sheets of homogenized tobacco material can be obtained by casting, extrusion, papermaking, or any other suitable methods known in the art.

The continuous sheet of aerosol generating material may be a smooth sheet. Alternatively, the continuous sheet may be processed to facilitate gathering of the sheet. For example, the continuous sheet may be embossed, shirred, folded, textured, embossed, or otherwise treated to provide relaxed lines to facilitate collection. The preferred processing of the continuous sheet is corrugation. As used herein, the term "corrugated" means a sheet having a plurality of substantially parallel folds or corrugations. The addition of one or more corrugated sheets may help maintain spacing between adjacent sheets within the core.

The sheets may be formed from porous tobacco material. The term "porous" is used herein to refer to a material that has multiple pores or holes to allow air to pass through the material. The tobacco material can be provided with internal porosity such that a sufficient number of pores or voids are provided within the structure of each sheet to allow air to flow through the sheet in the longitudinal direction. Alternatively or additionally, each sheet of tobacco material may include a plurality of airflow holes to provide the desired porosity. For example, a sheet of tobacco material may be punched with a pattern of airflow holes during the production of an aerosol generating substrate rod. Air flow holes can be randomly or evenly punched across the sheet. The pattern of airflow holes may substantially cover the entire surface of the sheet, or may cover one or more specific areas of the sheet, with the remaining areas having no airflow holes.

The cut pieces, strands or strips of tobacco material may be arbitrarily positioned within the rod. Alternatively, the cut pieces, strands or strips of tobacco material may be substantially parallel and aligned with the longitudinal axis of the rod.

In some embodiments, the aerosol generating substrate may be formed by collecting a continuous sheet of homogenized tobacco material transversely with respect to the longitudinal axis.

Preferably, the aerosol generating substrate contains an aerosol generating agent. As used herein, the term "aerosol generating agent" describes any suitable known compound or mixture of compounds which, when used, facilitates aerosol generation and which is substantially resistant to thermal degradation at the operating temperature of the aerosol generating article. Suitable aerosol forming agents are known in the art and include, but are not limited to: polyhydric alcohols such as propylene glycol, triethylene glycol, 1,3-butanediol, and glycerin; esters of polyhydric alcohols such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids such as dimethyl dodecanedioate and dimethyl tetradecanedioate. Preferred aerosol forming agents are polyhydric alcohols or mixtures thereof, such as propylene glycol, triethylene glycol, 1,3-butanediol, and most preferably glycerol.

The aerosolizing agent may be provided in the form of a liquid or a gel. In some embodiments, the aerosol generating agent may be provided in a composition further comprising nicotine, flavor, or both.

Homogenized tobacco materials may additionally contain various other additives such as humectants, plasticizers, flavors, fillers, binders, and solvents.

The aerosol generating substrate rod preferably has an outer diameter that is approximately equal to the outer diameter of the aerosol generating article.

Preferably, the aerosol generating substrate rod has an outer diameter of at least 5 millimeters. The aerosol generating substrate rod may have an outer diameter of from about 5 millimeters to about 12 millimeters, for example, from about 5 millimeters to about 10 millimeters, or from about 6 millimeters to about 8 millimeters. In a preferred embodiment, the aerosol generating substrate rod has an outer diameter of 7.2 millimeters to within 10 percent.

The aerosol generating substrate rod may have a length of from about 5 millimeters to about 100 mm. Preferably, the aerosol generating substrate rod has a length of at least about 5 millimeters, more preferably at least about 7 millimeters. Additionally or alternatively, the aerosol generating substrate rod preferably has a length of less than about 25 millimeters, more preferably less than about 20 millimeters. In one embodiment, the aerosol generating substrate rod may have a length of approximately 10 millimeters. In a preferred embodiment, the aerosol generating substrate rod has a length of approximately 12 millimeters.

Preferably, the aerosol generating substrate rod has a substantially uniform section along the length of the rod. Particularly preferably, the aerosol generating substrate rod has a substantially circular cross section.

The aerosol generating articles of the present invention comprise an aerosol generating substrate, which can be provided in the form of a rod containing strands of non-tobacco material surrounded by a wrapper. In the context of this document, the term "rod" is used to refer to a generally cylindrical element with a substantially circular, oval or elliptical cross section. As such, other and more complex thread cross-sections are also possible, such as star-shaped, X-shaped or Y-shaped. However, in the context of the present invention, such cross-sectional shapes that provide a sufficiently close packing of the filaments, but at the same time have a favorable ratio between the surface area of the circle circumscribed by the cross section of the filament and the effective surface area of the filament, are preferred. This is because, in the context of the present invention, shapes that allow a larger total volume of filaments to be packed in a rod are generally preferred over shapes that correspond to larger cumulative outer surface areas of the filaments. In this regard, a round shape or a quasi-round shape (such as oval or elliptical) is ideal. Triangular and rectangular sections are also possible. However, with triangular and rectangular sections, the filaments can even become too tightly packed, such as to reduce the space available for air flow between the filaments.

As described above, in the aerosol generating articles of the present invention, the aerosol generating substrate is surrounded by a wrapper. The wrapper may be formed from porous or non-porous sheet material. The wrapper may be formed from any suitable material or combination of materials. Preferably the wrapper is a paper wrapper.

Additionally, the aerosol generating articles of the present invention comprise at least one thermally expandable element located on the outer surface of the wrapper.

Preferably, at least one thermally expandable element contains a thermosetting material. In the context of this document, the term "thermosetting material" is used to describe a material that changes the shape or state of a substance when subjected to heat. This includes materials that retain a changed shape or state of matter when they are no longer exposed to heat, as well as materials that return to their undeformed shape or original state of matter when they are no longer exposed to heat.

In the context of this document, the term "deform" is used to describe an elastic or plastic change in the shape, dimensions, or shape and dimensions of an object. This includes expansion and compression.

More preferably, the thermosetting material is an intumescent reactive material.

The intumescent material may comprise any suitable material or materials. In some embodiments, the inflatable material forms an insulating foam when exposed to heat from the combustion zone of the smoking article. In one embodiment, the inflatable material contains a carbon source such as starch or one or more pentaerythritols (or other types of polyhydric alcohols), an acid source such as ammonium polyphosphate, an inflating agent such as melamine, and a binder such as soy lecithin. Additionally, an agent such as chlorinated paraffins may be added which improves the formation of the insulating foam. In an alternative embodiment, the inflatable material contains a mixture of sodium silicate and graphite, whereby a hard carbonaceous foam can be obtained when the inflatable material is exposed to heat during use of the aerosol generating article.

The intumescent material may be applied in the form of a thermoset coating formed by applying one or more of intumescent lacquers, paints, varnishes, or any combination thereof, to the interior surface of the closure body. For example, by brushing, rolling, dipping or spraying, or by using blown paper or a plastic-based sheet that is shaped into the final shape of the closure using any of the known closure manufacturing processes such as cutting, rolling and applying adhesive systems or molding into when using a plastic-based material. In one embodiment, the intumescent material is a latex-based solution applied by spraying.

Preferably, upon heating, the at least one thermally expandable element expands in the radial direction by at least about 0.01 millimeters. The radial expansion of a thermally expandable element is measured by heating the aerosol generating article under such conditions that nothing will physically prevent or restrict thermal expansion. It should be understood that, in contrast, when the aerosol generating article according to the present invention is heated inside the heating chamber of the aerosol generating device, the degree of expansion may be limited by the interaction of the thermally expandable member with the walls of the heating chamber.

More preferably, when heated, at least one thermally expandable element expands in the radial direction of at least about 0.05 millimeters. Even more preferably, when heated, at least one thermally expandable element expands in the radial direction of at least about 0.1 millimeters.

Additionally or alternatively, when heated, the at least one thermally expandable element preferably expands in the radial direction by less than about 1 millimeter. More preferably, when heated, at least one thermally expandable element expands in the radial direction by less than about 0.75 millimeters. Even more preferably, when heated, at least one thermally expandable element expands in the radial direction by less than about 0.5 millimeters.

Preferably, when heated, the thermoset expands at least about 1.1 times. In the context of this document, the term "expands at least 1.1 times" is used to mean that when subjected to heat, an element made from a thermoset material having a thickness of 1 millimeter in the undeformed state preferably expands to a thickness of at least about 1. 1 millimeter. The expansion of a thermally expandable element is measured by heating the aerosol generating article under such conditions that nothing will physically interfere with or limit thermal expansion.

More preferably, when heated, the thermoset expands at least about 2 times. Even more preferably, when heated, the thermoset expands at least about 5 times. More preferably, when heated, the thermoset expands at least about 10 times.

Preferably, the aerosol generating article of the present invention expands at least about 1.001 times. In other words, an aerosol generating article having an undeformed outer diameter of about 7 millimeters at the site of at least one thermally expandable member will expand to an outer diameter of at least about 7.01 millimeters when exposed to heat. More preferably, the aerosol generating article expands at least about 1.007 times. Even more preferably, the aerosol generating article expands at least about 1.014 times.

Additionally or alternatively, the aerosol generating article expands by less than about 1.14 times. More preferably, the aerosol generating article expands less than about 1.107 times. Even more preferably, the aerosol generating article expands by less than about 1.07 times.

Preferably, the length of the thermally expandable element is at least about 0.5 millimeters. In the present description, the term "length" is used to refer to the size of the aerosol generating component of the article, which is measured in the longitudinal direction of the article. More preferably, the length of the thermally expandable element is at least about 1 millimeter. Even more preferably, the length of the thermally expandable element is at least about 2 millimeters.

Additionally or alternatively, the length of the thermally expandable element is preferably less than about 15 millimeters. More preferably, the length of the thermally expandable element is less than about 10 millimeters. Even more preferably, the length of the thermally expandable element is less than about 5 millimeters.

Preferably, the surface area of the outer surface area of the wrapper covered with the thermally expandable element is at least about 7.5 square millimeters. More preferably, the surface area of the outer surface area of the wrapper covered with the thermally expandable element is at least about 15 square millimeters. Even more preferably, the surface area of the outer surface area of the wrapper covered with the thermally expandable element is at least about 30 square millimeters.

Additionally or alternatively, the surface area of the outer surface area of the wrapper covered with the thermally expandable element is preferably less than about 600 square millimeters. More preferably, the surface area of the outer surface area of the wrapper covered with the thermally expandable element is less than about 400 square millimeters. Even more preferably, the surface area of the outer surface area of the wrapper covered with the thermally expandable element is less than about 200 square millimeters.

In some embodiments, at least one thermally expandable element extends around the circumference of the wrapper. In alternative embodiments, the aerosol generating article comprises a plurality of separate thermally expandable elements located at various locations around the circumference of the wrapper.

Preferably, the thermosetting material is evenly spaced around the circumference of the wrapper. This presents the advantage that preference is given to centering the aerosol generating article within the heating chamber. Without being limited by theory, it should be understood that if the aerosol generating article is inserted into the heating chamber in a position other than the coaxial position, then one part of the thermally expandable element will be located closer to the heat source than the rest of the thermally expandable element, and thus thus, will typically expand faster than the rest of the thermally expandable element. The interaction of the expanded part of the thermally expandable element with a part of the wall of the heating chamber should lead to a shift of the thermally expandable element inside the heating chamber towards a position closer to the center.

In some embodiments, at least one thermally expandable element may comprise a first layer containing a first thermoset material and a radially outer second layer adjacent the first layer containing a second thermoset material. The coefficient of thermal expansion of the first thermosetting material is less than the coefficient of thermal expansion of the second thermosetting material. In some embodiments, the coefficient of thermal expansion of the first reactive material, that is, the coefficient of thermal expansion of the layer closest in the radial direction to the wrapper, may even be negative. In other words, the first reactive material may even shrink during heating, provided that the thermally expandable member as a whole expands under the influence of heat during use of the aerosol generating article. Without being limited by theory, it should be understood that in these embodiments, the implementation of the thermally expandable element can be bent and bent outward.

By way of example, in embodiments in which the thermally expandable member comprises two or more layers having different coefficients of thermal expansion, the thermoset material or materials may be selected from bimetals, shape memory alloys, and combinations thereof. In the case of bimetals, the high thermal expansion layer is also referred to as the "active component" and may comprise an alloy containing two or more of nickel, iron, manganese and chromium. The lower thermal expansion layer is also referred to as the "passive component" and may comprise an iron-nickel alloy such as, for example, Invar®, a 36% nickel-iron alloy that has a substantially zero thermal expansion coefficient.

Preferably, the distance between the at least one thermally expandable element and the mouth end of the aerosol generating article is greater than about 50 percent of the total length of the aerosol generating article. Thus, at least one thermally expandable element is positioned closer to the distal end of the article, which means that the effect of the cleaning action is maximized when the article is removed from the heating chamber of the aerosol generating device after use. More preferably, the distance between the at least one thermally expandable element and the mouth end of the aerosol generating article is greater than about 60 percent of the total length of the aerosol generating article. Even more preferably, the distance between the at least one thermally expandable element and the mouth end of the aerosol generating article is greater than about 70 percent of the total length of the aerosol generating article.

Additionally or alternatively, the distance between the at least one thermally expandable element and the mouth end of the aerosol generating article is preferably less than about 95 percent of the total length of the aerosol generating article. More preferably, the distance between the at least one thermally expandable member and the mouth end of the aerosol generating article is less than about 85 percent of the total length of the aerosol generating article.

In particularly preferred embodiments, the distance between the at least one thermally expandable member and the mouth end of the aerosol generating article is from about 50 percent to about 95 percent of the total length of the aerosol generating article, more preferably from about 60 percent to about 85 percent of the total length of the aerosol generating article. the total length of the product generating the aerosol. Aerosol generating articles containing a thermally expandable element at a distance from the mouth end that falls within these ranges advantageously combine a satisfactory cleaning effect with a particularly stable and balanced placement of the aerosol generating article within the heating chamber of the aerosol generating device.

In addition, such aerosol generating articles may be particularly advantageous when used in an aerosol generating device comprising an induction heater. In one such aerosol generating device, the heater may include: a pin extending into the heating chamber and operatively connected to an induction coil located along the pin; and a power source connected to the induction coil and configured to supply high frequency current to the induction coil. In one such configuration, the thermally expandable element provides the desired restricting and blocking effect.

Preferably, the distance between the at least one thermally expandable member and the heat source of the aerosol generating article is less than about 20 millimeters. More preferably, the distance between the at least one thermally expandable element and the heat source is less than about 10 millimeters. Even more preferably, the distance between the at least one thermally expandable element and the heat source is less than about 5 millimeters.

Preferably, the undeformed thickness of at least one thermally expandable element is at least about 0.05 millimeters. More preferably, the undeformed thickness of at least one thermally expandable element is at least about 0.1 millimeters. Even more preferably, the thickness of at least one thermally expandable element in the undeformed state is at least about 0.2 millimeters. Additionally or alternatively, the undeformed thickness of at least one thermally expandable element is preferably less than about 2 millimeters.

The aerosol generating articles of the present invention preferably comprise one or more elements in addition to the aerosol generating substrate rod. The rod and one or more elements may be assembled within the same substrate wrapper. For example, the aerosol generating articles of the present invention may further comprise at least one of: a mouthpiece, an aerosol cooling element, and a support element such as a hollow acetate tube. For example, in one preferred embodiment, the aerosol generating article comprises, in a linear serial configuration, an aerosol generating substrate rod as described above, a support member immediately downstream of the aerosol generating substrate, an aerosol cooling member located downstream. the direction of flow relative to the support element, a wrapper surrounding the rod, the support element and the element that cools the aerosol.

It should be understood that in aerosol generating articles comprising one or more elements, in addition to a rod of aerosol generating substrate surrounded by a wrap, a thermally expandable element located on the outer surface of the wrap may be in place along the aerosol generating substrate, or at a location along one of one or more additional elements.

Depending on the overall length of the aerosol generating article, placing the thermally expandable member in place along one of the one or more accessory members may further stabilize the aerosol generating article within the heating chamber. On the other hand, placing the thermally expandable member in place along the aerosol generating substrate will generally improve the cleaning effect associated with removing the aerosol generating article from the heating chamber.

In some embodiments, the aerosol generating article may include an additional outer wrapper surrounding the thermally expandable element. Thus, in such embodiments, the thermally expandable member rests on top of a wrapper surrounding at least the aerosol generating substrate rod and lies underneath the outer wrapper. This may be desirable since the thermally expandable member is not visible and the aerosol generating article is provided with a smoother outer coating. This may, in turn, simplify the handling and packaging of aerosol generating articles.

Aerosol generating articles as described above may be used in conjunction with electrical aerosol generating devices. More specifically, the aerosol generating system according to the present invention comprises an aerosol generating aerosol product and an electrical aerosol generating device, wherein the aerosol generating device comprises a heater and an elongated heating chamber configured to accommodate the aerosol generating product, so that the aerosol generating article is heated in the heating chamber. The aerosol generating article comprises an aerosol generating substrate rod, a wrapper surrounding the rod, and at least one thermally expandable element located on the outer surface of the wrapper, as described above. The outer diameter of the surrounded rod is smaller than the inner diameter of the heating chamber. In addition, the thermally expandable element is configured to deform when heated in the heating chamber so that at least a portion of the thermally expandable element is in contact with the inner surface of the heating chamber.

Thus, during use, the aerosol generating article is advantageously held in place within the heating chamber, and therefore the likelihood that the aerosol generating article slips out of the heating chamber is greatly reduced.

Preferably, the heater comprises a substantially cylindrical elongated heating element and the heating chamber is located around the circumferential longitudinal surface of the heater. Accordingly, during use, thermal energy supplied by the heater passes radially outward from the surface of the heater into the heating chamber and the aerosol generating article.

Thus, the placement of the aerosol generating article within the heating chamber can be even more precisely controlled. In particular, the aerosol generating article may be centered and substantially coaxial with the heating chamber such that the distance between the outer surface of the aerosol generating article and the wall of the heating chamber is substantially constant with respect to the circumference of the aerosol generating article. This advantageously provides a more uniform transfer of heat from the heater to the aerosol generating substrate during use, thereby reducing the likelihood of hot spots within the substrate.

However, other shapes and configurations of the heater and heating chamber may be used as an alternative.

The heater may comprise a plurality of separate heating elements, the various heating elements being independently controllable such that different elements may be activated at different times to heat the aerosol generating article. For example, the heater may comprise multiple axially aligned heating elements that provide multiple independent heating zones along the length of the heater. Each heating element may have a length substantially less than the total length of the heater. Thus, when one individual heating element is activated, it supplies thermal energy to the portion of the aerosol generating substrate located radially adjacent to the heating element without substantially heating the remainder of the aerosol generating substrate. Thus, different sections of the aerosol generating substrate can be heated independently and at different times. By way of example, it may be possible to control the activation of the heater so that during use the heating element located at the axial location facing the thermally expandable element in use is activated first. In this way, the aerosol generating article can be immediately stabilized and held in place within the heating chamber before full aerosol generation begins.

Alternatively or additionally, the heater may comprise a plurality of elongated longitudinally extending heating elements at different locations around the longitudinal axis of the heater. Thus, when one single heating element is activated, it supplies thermal energy to a longitudinal portion of the aerosol generating substrate lying substantially parallel to and adjacent to the heating element. This configuration also allows the aerosol generating substrate to be independently heated in different parts.

In preferred embodiments, the aerosol generating system further comprises an insulating means placed between the heating chamber and the exterior of the device to reduce heat loss from the heated aerosol generating substrate.

Hereinafter, the present invention will be further described with reference to the figures, in which:

in fig. 1 is a schematic side cross-sectional view of an aerosol generating article in accordance with the present invention;

in fig. 2 is a schematic side cross-sectional view of the aerosol generating article according to the present invention placed inside the heating chamber of the aerosol generating device before the introduction of thermal energy; and

in fig. 3 is a schematic side cross-sectional view of the aerosol generating article shown in FIG. 2, after the introduction of thermal energy.

The aerosol generating article 10 shown in FIG. 1 comprises a rod 12 of an aerosol generating substrate and a wrapper 14 surrounding the rod 12. Arrow A indicates the direction of flow of the aerosol during use, thus indicating the mouth end 16 of the rod 12.

In the embodiment of FIG. 1 part of the stem 12 is further surrounded by a strip of pressure-resistant paper 18, which is connected to other parts of the wrapper 14 by another strip of wrapping paper 20.

In addition, the product 10, generating aerosol, contains a thermally expandable element 22, located on the outer surface of the strip 20 of wrapping paper. The thermally expandable member 22 is made from an inflatable reactive material that can expand to approximately 10 times its original dimensions when subjected to heat. The thermally expandable member 22 is provided as an annular member extending around the circumference of the wrapping paper strip 20 such that the intumescent material is evenly distributed around the circumference of the wrapper.

In FIG. 2 and 3 depict another embodiment of an aerosol generating article 30 in accordance with the present invention. The aerosol generating article 30 comprises an aerosol generating substrate rod 32 and a wrapper 34 surrounding the rod 32. In addition, the aerosol generating article 30 includes a plurality of thermally expandable elements 36 located on the outer surface of the wrapper 34. The thermally expandable elements 36 are located substantially equidistant around the circumference of wrap 34. Thermally expandable members 36 are attached to wrapper 34 by a layer of heat-resistant adhesive 38. Each thermally expandable member 36 comprises a first layer containing a first thermoset material and a radially outer second layer adjacent the first layer. and containing a second thermosetting material. The coefficient of thermal expansion of the first thermosetting material is less than the coefficient of thermal expansion of the second thermosetting material. The aerosol generating article 30 is housed in the heating chamber 50 of the aerosol generating device 48.

In FIG. 2 shows the aerosol generating article 30 before use, that is, before being exposed to the heat of the aerosol generating device 50. Thus, the thermally expandable members 36 are shown in an undeformed (ie, unexpanded) state. In FIG. 3 shows the aerosol generating article 30 during use after exposure to sufficient heat to change the state of the thermally expandable member from undeformed to expanded. Due to the different coefficients of thermal expansion of the two layers 38 and 40, the thermally expandable elements 36 adopt a curved C-shape configuration so that they can contact the surface of the heating chamber at their respective ends, which are effectively curved outward from the central portion of the thermally expandable element.

Claims (21)

1. An aerosol-generating article for producing an inhalable aerosol when heated, wherein the aerosol-generating article contains: an aerosol generating substrate rod; a wrapper surrounding at least the rod; at least one thermally expandable element located on the outer surface of the wrapper. 2. An aerosol generating article according to claim 1, characterized in that said at least one thermally expandable element comprises a thermosetting material. 3. An aerosol generating article according to claim 2, characterized in that the thermosetting material is an intumescent reactive material. 4. An aerosol generating article according to claim 2 or 3, characterized in that the thermoset expands at least 1.1 times when heated. 5. An aerosol generating article according to any one of claims 1 to 4, characterized in that said at least one thermally expandable element expands by a factor of 10 to 100 relative to its original dimensions when exposed to heat. 6. An aerosol generating article according to any one of claims 1 to 5, characterized in that said at least one thermally expandable element extends around the circumference of the wrapper. 7. An aerosol generating article according to any one of claims 1 to 5, characterized in that it comprises a plurality of thermally expandable elements located at various locations around the circumference of the wrapper. 8. An aerosol generating article according to any one of claims 2 to 7, characterized in that the thermosetting material is evenly distributed around the circumference of the wrapper. 9. An aerosol-generating article according to any one of claims 2 to 8, characterized in that said at least one thermally expandable element comprises a first layer containing a first thermosetting material and a radially outer second layer adjacent to the first layer, containing a second thermosetting material, wherein the coefficient of thermal expansion of the first thermosetting material is less than the coefficient of thermal expansion of the second thermosetting material. 10. An aerosol generating article according to any of the preceding claims, characterized in that the distance between said at least one thermally expandable element and the mouth end of the aerosol generating article is greater than 50 percent of the total length of the aerosol generating article. 11. An aerosol generating article according to any one of the preceding claims, characterized in that the undeformed thickness of said at least one thermally expandable element is at least 0.05 mm. 12. An aerosol-generating article according to any one of the preceding claims, further comprising, in a linear sequential configuration, a support element located immediately downstream of the aerosol-generating substrate, an aerosol-cooling element located downstream of the support element. element, a wrapper surrounding the rod, the support element and the cooling spray element. 13. An aerosol generating system comprising an aerosol generating aerosol product and an aerosol generating electrical device comprising a heater and an elongated heating chamber configured to accommodate the aerosol generating product such that the aerosol generating product is heated in the heating chamber. , while the aerosol generating product contains: an aerosol generating substrate rod; a wrapper surrounding at least the rod, wherein the outer diameter of the surrounded rod is less than the inner diameter of the heating chamber; and at least one thermally expandable element located on the outer surface of the wrapper, wherein the thermally expandable element is deformable when heated in the heating chamber so that at least part of the thermally expandable element is in contact with the inner surface of the heating chamber. 14. An aerosol generating system according to claim 13, characterized in that the heater comprises a cylindrical elongated heating element and the heating chamber is located around the circumferential longitudinal surface of the heater. 15. An aerosol generating system according to claim 13 or 14, characterized in that it comprises an insulating means placed between the heating chamber and the exterior of the device to reduce heat loss from the heated aerosol generating substrate.

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