REINFORCED HEAT SOURCE
A reinforced heat source (4) for an aerosol-generating article (2), the reinforced heat source comprising: a blind combustible heat source (38) having a length L; and a non-combustible support (40) embedded in the combustible heat source, wherein the non-combustible support does not protrude outwardly from the combustible heat source.
The present invention relates to a reinforced heat source for an aerosol-generating article and to an aerosol-generating article comprising the reinforced heat source and an aerosol-forming substrate.
A number of aerosol-generating articles in which tobacco material is heated rather than combusted have been proposed in the art. An aim of such ‘heated’ aerosol-generating articles is to reduce known harmful smoke constituents of the type produced by the combustion and pyrolytic degradation of tobacco in conventional cigarettes.
Typically in heated aerosol-generating articles, an aerosol is generated by the transfer of heat from a heat source, for example, a chemical, electrical or combustible heat source, to a physically separate aerosol-forming substrate, which may be located within, around or downstream of the heat source.
In one type of heated aerosol-generating article, an aerosol is generated by the transfer of heat from a combustible heat source to a physically separate aerosol-forming substrate that is located downstream of the combustible heat source. In use, volatile compounds are released from the aerosol-forming substrate by heat transfer to the aerosol-forming substrate from the combustible heat source and entrained in air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol that is inhaled by the user. Heat may be transferred from the combustible heat source to the aerosol-forming substrate by one or both of forced convection and conduction.
In this type of heated aerosol-generating article, it is known to include a heat-conducting element around and at least a rear portion of the combustible carbonaceous heat source and at least a front portion of the aerosol-forming substrate of the aerosol-generating article in order to ensure sufficient conductive heat transfer from the combustible heat source to the aerosol-forming substrate to obtain an acceptable aerosol. For example, WO 2009/022232 A2 discloses a smoking article comprising a combustible carbonaceous heat source with a central airflow channel, an aerosol-forming substrate downstream of the combustible heat source, and a heat-conducting element around and in contact with a rear portion of the combustible carbonaceous heat source and an adjacent front portion of the aerosol-forming substrate. In use, heat generated during combustion of the combustible carbonaceous heat source is transferred to the periphery of the front portion of the aerosol-forming substrate by conduction through the abutting downstream end of the combustible carbonaceous heat source and the heat-conducting element. In addition, air drawn through the smoking article by the user is heated as it passes through the central airflow channel of the combustible carbonaceous heat source and then heats the aerosol-generating substrate by convection.
The combustion temperature of combustible heat sources for use in heated aerosol-generating articles should not be so high as to result in combustion or thermal degradation of the aerosol-forming substrate during use of the aerosol-generating article. However, the combustion temperature of the combustible heat sources should be sufficiently high to generate enough heat to release sufficient volatile compounds from the aerosol-forming substrate to produce an acceptable aerosol, especially during early puffs.
A variety of combustible heat sources for use in heated aerosol-generating articles are known in the art.
Known combustible heat sources for use in heated aerosol-generating articles are often prone to damage prior to and during use thereof. For example, known combustible heat sources combustible heat sources for use in heated aerosol-generating articles are often prone to cracking. Damage to a combustible heat source may result in fragmentation of the combustible heat source during use of a heated aerosol-generating article. This may lead to loss of combustible material from the combustible heat source during use of the heated aerosol-generating article. In particular, it may lead to ‘fall-off’ or ‘drop-off’ of some or all of the combustible heat source during use of the heated aerosol-generating article.
Loss of combustible material from a combustible heat source during use of a heated aerosol-generating article may result in less fuel being available for combustion. This may disadvantageously affect the amount of heat transferred from the combustible heat source to the aerosol-forming substrate and may disadvantageously affect the release of volatile compounds from the aerosol-forming substrate of the heated aerosol-generating article.
Loss of combustible material from a combustible heat source during use of a heated aerosol-generating article may disadvantageously create a mess and may detrimentally affect the appearance of the heated aerosol-generating article.
Loss of combustible material from a combustible heat source during use of a heated aerosol-generating article may disadvantageously cause safety issues for a user of the heated aerosol-generating article.
Known combustible heat sources for use in heated aerosol-generating articles often do not generate enough heat after ignition thereof to produce an acceptable aerosol during early puffs. Known combustible heat sources for use in heated aerosol-generating articles are often difficult to ignite. Failure to properly ignite a combustible heat source may lead to an unacceptable aerosol being delivered to a user during use of the heated aerosol-generating article.
It has been proposed to include oxidizing agents and other additives in combustible heat sources for use in heated aerosol-generating articles in order to improve the ignition and combustion properties thereof. For example, WO 2012/164077 A1 discloses a combustible heat source for a smoking article comprising carbon and at least one ignition aid selected from the group consisting of metal nitrate salts having a thermal decomposition temperature of less than about 600 degrees Celsius, chlorates, peroxides, thermitic materials, intermetallic materials, magnesium, zirconium, and combinations thereof.
Inclusion of ignition aids may render known combustible heat sources for use in heated aerosol-generating articles more prone to damage prior to and during use thereof. For example, inclusion of oxidizing agents that release oxygen during ignition and combustion of known combustible heat sources may render known combustible heat sources more prone to fragmentation during use thereof. In such known combustible heat sources, the oxygen generated within the combustible heat source during ignition and combustion thereof tends to expand. The pressure generated by the expanding oxygen may lead to cracking and fragmentation of the combustible heat source. This may lead to ‘fall-off’ or ‘drop-off’ of some or all of the combustible heat source during use of the heated aerosol-generating article.
It would be desirable to provide a heat source for use in heated aerosol-generating articles that exhibits improved mechanical integrity during use thereof compared to known combustible heat sources.
It would be desirable to provide a heat source for use in heated aerosol-generating articles that is less prone to fragmentation during use thereof than known combustible heat sources.
It would be desirable to provide a heat source for use in heated aerosol-generating articles that is less prone to ‘fall-off’ or ‘drop-off’ during use thereof than known combustible heat sources.
The invention relates to a reinforced heat source for an aerosol-generating article. The reinforced combustible heat source may comprise a combustible heat source. The combustible heat source may be a blind combustible heat source. The combustible heat source may have a length L. The reinforced heat source may comprise a non-combustible support. The non-combustible support may be embedded in the combustible heat source. The non-combustible support may protrude outwardly from the combustible heat source by a distance of less than or equal to 0.1 L.
The invention also relates to an aerosol-generating article. The aerosol-generating article may comprise a reinforced heat source. The reinforced combustible heat source may comprise a combustible heat source. The combustible heat source may be a blind combustible heat source. The combustible heat source may have a length L. The reinforced heat source may comprise a non-combustible support. The non-combustible support may be embedded in the combustible heat source. The non-combustible support may protrude outwardly from the combustible heat source by a distance of less than or equal to 0.1 L. The aerosol-generating article may comprise an aerosol-generating substrate.
According to the invention there is provided a reinforced heat source for an aerosol-generating article, the reinforced heat source comprising: a combustible heat source having a length L; and a non-combustible support embedded in the combustible heat source, wherein the non-combustible support protrudes outwardly from the combustible heat source by a distance of less than or equal to 0.1 L.
According to the invention there is provided a reinforced heat source for an aerosol-generating article, the reinforced heat source comprising: a combustible heat source having a length L; and a non-combustible support embedded in the combustible heat source, wherein the combustible heat source does not protrude outwardly from the combustible heat source.
According to the invention there is provided a reinforced heat source for an aerosol-generating article, the reinforced heat source comprising: a combustible heat source having a length L; and a non-combustible support embedded in the combustible heat source, wherein the combustible heat source completely surrounds the non-combustible support.
According to the invention there is further provided an aerosol-generating article comprising: a reinforced heat source comprising a combustible heat source having a length L and a non-combustible support embedded in the combustible heat source, wherein the non-combustible support protrudes outwardly from the combustible heat source by a distance of less than or equal to 0.1 L; and an aerosol-forming substrate.
According to the invention there is further provided an aerosol-generating article comprising: a reinforced heat source comprising a combustible heat source having a length L and a non-combustible support embedded in the combustible heat source, wherein the non-combustible support does not protrude outwardly from the combustible heat source; and an aerosol-forming substrate.
According to the invention there is further provided an aerosol-generating article comprising: a reinforced heat source comprising a combustible heat source having a length L and a non-combustible support embedded in the combustible heat source, wherein the combustible heat source completely surrounds the non-combustible support; and an aerosol-forming substrate.
According to the invention there is provided a reinforced heat source for an aerosol-generating article, the reinforced heat source comprising: a blind combustible heat source having a length L; and a non-combustible support embedded in the combustible heat source, wherein the non-combustible support protrudes outwardly from the combustible heat source by a distance of less than or equal to 0.1 L.
According to the invention there is provided a reinforced heat source for an aerosol-generating article, the reinforced heat source comprising: a blind combustible heat source having a length L; and a non-combustible support embedded in the combustible heat source, wherein the non-combustible support does not protrude outwardly from the combustible heat source.
According to the invention there is provided a reinforced heat source for an aerosol-generating article, the reinforced heat source comprising: a blind combustible heat source having a length L; and a non-combustible support embedded in the combustible heat source, wherein the combustible heat source completely surrounds the non-combustible support.
According to the invention there is further provided an aerosol-generating article comprising: a reinforced heat source comprising a blind combustible heat source having a length L and a non-combustible support embedded in the combustible heat source, wherein the non-combustible support protrudes outwardly from the combustible heat source by a distance of less than or equal to 0.1 L; and an aerosol-forming substrate.
According to the invention there is further provided an aerosol-generating article comprising: a reinforced heat source comprising a blind combustible heat source having a length L and a non-combustible support embedded in the combustible heat source, wherein the non-combustible support does not protrude outwardly from the combustible heat source; and an aerosol-forming substrate.
According to the invention there is further provided an aerosol-generating article comprising: a reinforced heat source comprising a blind combustible heat source having a length L and a non-combustible support embedded in the combustible heat source, wherein the combustible heat source completely surrounds the non-combustible support; and an aerosol-forming substrate.
It has been found that inclusion of a non-combustible support embedded in the combustible heat source of reinforced heat sources according to the invention may advantageously improve the mechanical stability of the combustible heat source of reinforced heat sources according to the invention during use thereof.
It has been found that inclusion of a non-combustible support embedded in the combustible heat source of reinforced heat sources according to the invention may advantageously reduce or prevent fragmentation of the combustible heat source of reinforced heat sources according to the invention during use thereof.
It has been found that inclusion of a non-combustible support embedded in the combustible heat source of reinforced heat sources according to the invention may advantageously reduce or prevent ‘fall-off’ or ‘drop-off’ of the combustible heat source of reinforced heat sources according to the invention during use thereof.
Without wishing to be bound by theory, it is believed that inclusion of a non-combustible support embedded in the combustible heat source of reinforced heat sources according to the invention increases the bonding forces inside the combustible heat source.
Where the combustible heat source comprises an oxidizing agent that releases oxygen during ignition and combustion of the combustible heat source, inclusion of the non-combustible support may advantageously increase the bonding forces inside the combustible heat sufficiently to withstand the pressure generated by expansion of the oxygen.
Inclusion of a non-combustible support embedded in the combustible heat source of reinforced heat sources according to the invention, wherein the non-combustible support protrudes outwardly from the combustible heat source by a distance of less than or equal to 0.1 L, may advantageously have minimal impact on the ignition and combustion of the combustible heat source.
Inclusion of a non-combustible support embedded in the combustible heat source of reinforced heat sources according to the invention, wherein the non-combustible support protrudes outwardly from the combustible heat source by a distance of less than or equal to 0.1 L, may advantageously have minimal impact on the generation of heat by the combustible heat source during combustion thereof.
Inclusion of a non-combustible support embedded in the combustible heat source of reinforced heat sources according to the invention, wherein the non-combustible support protrudes outwardly from the combustible heat source by a distance of less than or equal to 0.1 L, may advantageously have minimal impact on heat transfer from the combustible heat source to the aerosol-forming substrate of aerosol-generating articles according to the invention during use thereof.
Inclusion of a non-combustible support embedded in the combustible heat source of reinforced heat sources according to the invention, wherein the non-combustible support protrudes outwardly from the combustible heat source by a distance of less than or equal to 0.1 L, may advantageously have minimal impact on the external appearance of reinforced combustible heat sources and aerosol-generating articles according to the invention.
As used herein with reference to the invention, the terms “distal”, “upstream” and “front” and the terms “proximal”, “downstream” and “rear” are used to describe the relative positions of components, or portions of components, of aerosol-generating articles according to the invention. Aerosol-generating articles according to the invention comprise a proximal end through which, in use, an aerosol exits the aerosol-generating article for delivery to a user. The proximal end of the aerosol-generating article may also be referred to as the mouth end of the aerosol-generating article. In use, a user draws on the proximal end of the aerosol-generating article in order to inhale an aerosol generated by the aerosol-generating article.
Aerosol-generating articles according to the invention comprise a distal end. The reinforced heat source is located at or proximate to the distal end of the aerosol-generating article. Components, or portions of components, of aerosol-generating articles according to the invention may be described as being upstream or downstream of one another based on their relative positions between the proximal end of the aerosol-generating article and the distal end of the aerosol-generating article.
The proximal end of the aerosol-generating article is downstream of the distal end of the aerosol-generating article. The proximal end of the aerosol-generating article may also be referred to as the downstream end of the aerosol-generating article and the distal end of the aerosol-generating article may also be referred to as upstream end of the aerosol-generating article.
The combustible heat source of reinforced heat sources according to the invention has a front end face and a rear end face. The front end face of the combustible heat source is at the upstream end of the combustible heat source. The upstream end of the combustible heat source is the end of the combustible heat source furthest from the proximal end of the aerosol-generating article. The rear end face of the combustible heat source is at the downstream end of the combustible heat source. The downstream end of the combustible heat source is the end of the combustible heat source closest to the proximal end of the aerosol-generating article.
As used herein with reference to the invention, the term “longitudinal” is used to describe the direction between the upstream end and the downstream end of the combustible heat source of reinforced heat sources according to the invention and aerosol-generating articles according to the invention.
As used herein with reference to the invention, the term “transverse” is used to describe the direction perpendicular to the longitudinal direction. That is, the direction perpendicular to the direction between the upstream end and the downstream end of the combustible heat source of reinforced heat sources according to the invention and aerosol-generating articles according to the invention.
The combustible heat source of reinforced heat sources according to the invention has a length L.
As used herein with reference to the invention, the term “length” is used to describe the maximum dimension in the longitudinal direction of the combustible heat source of reinforced heat sources according to the invention and aerosol-generating articles according to the invention.
The combustible heat source may have any desired length L.
The combustible heat source may have a length L of between about 5 millimetres and about 20 millimetres.
Preferably, the combustible heat source has a length L of between about 7 millimetres and about 17 millimetres.
More preferably, the combustible heat source has a length L of between about 7 millimetres and about 15 millimetres.
Most preferably, the combustible heat source has a length L of between about 7 millimetres and about 13 millimetres.
As used herein with reference to the invention, the term “diameter” is used to describe the maximum dimension in the transverse direction of the combustible heat source of reinforced heat sources according to the invention and aerosol-generating articles according to the invention.
The combustible heat source of reinforced heat sources according to the invention may have any desired diameter.
The combustible heat source may have a diameter of between about 5 millimetres and about 15 millimetres.
Preferably, the combustible heat source has a diameter of between about 5 millimetres and about 10 millimetres.
More preferably, the combustible heat source has a diameter of between about 7 millimetres and about 8 millimetres.
Preferably, the combustible heat source is substantially cylindrical.
The combustible heat source is a solid combustible heat source.
Preferably, the combustible heat source is a monolithic solid combustible heat source. That is, a one-piece solid combustible heat source.
The combustible heat source may have a mass of between about 300 milligrams and about 500 milligrams. For example, the combustible heat source may have a mass of between about 400 milligrams and about 450 milligrams.
Preferably, the combustible heat source is a carbonaceous combustible heat source.
As used herein with reference to the invention, the term “carbonaceous” is used to describe a combustible heat source comprising carbon.
The combustible heat source may comprise at least about 25 percent by weight of carbon.
Unless stated otherwise, percentages by weight of components of the combustible heat source recited herein are based on the total dry weight of the combustible heat source.
Preferably, the combustible heat source comprises at least about 30 percent by weight of carbon.
More preferably, the combustible heat source comprises at least about 35 percent by weight of carbon.
The combustible heat source may comprise at least about 40 percent by weight of carbon.
The combustible heat source may comprise less than or equal to about 60 percent by weight of carbon.
Preferably, the combustible heat source comprises less than or equal to about 55 percent by weight of carbon.
More preferably, the combustible heat source comprises less than or equal to about 50 percent by weight of carbon.
The combustible heat source may comprise less than or equal to about 45 percent by weight of carbon.
The combustible heat source may comprise between about 25 percent by weight and about 60 percent by weight of carbon, between about 25 percent by weight and about 55 percent by weight of carbon, between about 25 percent by weight and about 50 percent by weight of carbon or between about 25 percent by weight and about 45 percent by weight of carbon.
Preferably, the combustible heat source comprises between about 30 percent by weight and about 60 percent by weight of carbon, between about 30 percent by weight and about 55 percent by weight of carbon, between about 30 percent by weight and about 50 percent by weight of carbon or between about 30 percent by weight and about 45 percent by weight of carbon.
More preferably, the combustible heat source comprises between about 35 percent by weight and about 60 percent by weight of carbon, between about 35 percent by weight and about 55 percent by weight of carbon, between about 35 percent by weight and about 50 percent by weight of carbon or between about 35 percent by weight and about 45 percent by weight of carbon.
The combustible heat source may comprise between about 40 percent by weight and about 60 percent by weight of carbon, between about 40 percent by weight and about 55 percent by weight of carbon, between about 40 percent by weight and about 50 percent by weight of carbon or between about 40 percent by weight and about 45 percent by weight of carbon.
The combustible heat source may be formed using one or more suitable carbon materials. Advantageously, the combustible heat source comprise one or more carbonised materials. Suitable carbon materials are well known in the art and include, but are not limited to, carbon powder and charcoal powder.
Preferably, the combustible heat source comprises an oxidizing agent that releases oxygen during ignition of the combustible heat source. The quantity of oxygen released by the oxidizing agent during ignition of the combustible heat source may be sufficient to result in the combustible heat source undergoing a two-stage combustion process.
In an initial first stage the combustible heat source may exhibit a ‘boost’ in temperature and in a subsequent second stage the combustible heat source may undergo sustained combustion at a lower ‘cruising’ temperature.
The initial ‘boost’ in temperature of combustible heat source may arise due to very rapid propagation of heat throughout the entirety of the combustible heat source upon ignition of a portion thereof. The very rapid propagation of heat may be the result of a chain reaction in which a portion of the combustible heat source that is ignited triggers the ignition of an adjacent unignited part of the combustible heat source.
In use in aerosol-generating articles according to the invention, the rapid increase in temperature of the combustible heat source to the ‘boost’ temperature may quickly raise the temperature of the aerosol-forming substrate to a level at which volatile compounds are released from the aerosol-forming substrate. This may ensure that aerosol-generating articles according to the invention produce a sensorially acceptable aerosol during early puffs. The subsequent decrease in temperature of the combustible heat source to the ‘cruising’ temperature may ensure that the temperature of the aerosol-forming substrate does not reach a level at which combustion or thermal degradation of the aerosol-forming substrate occurs.
Controlling the temperature of the combustible heat source of reinforced heat sources according to the invention in the manner described above may advantageously enable aerosol-generating articles according to the invention to be provided that not only produce a sensorially acceptable aerosol during early puffs, but in which combustion or thermal degradation of the aerosol-forming substrate is also substantially avoided.
The amount of oxidizing agent that must be included in order to achieve the two-stage process described above will vary depending on the specific oxidizing agent included in the combustible heat source.
Preferably, the oxidizing agent is an alkaline earth metal peroxide.
More preferably, the oxidizing agent is calcium peroxide.
The combustible heat source may comprise at least about 15 percent by weight of calcium peroxide.
Preferably, the combustible heat source comprises at least about 20 percent by weight of calcium peroxide.
More preferably, the combustible heat source comprises at least about 30 percent by weight of calcium peroxide.
The combustible heat source may comprise at least about 40 percent by weight of calcium peroxide.
The combustible heat source may comprise less than or equal to about 65 percent by weight of calcium peroxide.
Preferably, the combustible heat source comprises less than or equal to about 60 percent by weight of calcium peroxide.
More preferably, the combustible heat source comprises less than or equal to about 55 percent by weight of calcium peroxide.
The combustible heat source may comprise less than or equal to about 50 percent by weight of calcium peroxide.
The combustible heat source may comprise between about 15 percent by weight and about 65 percent by weight of calcium peroxide, between about 15 percent by weight and about 60 percent by weight of calcium peroxide, between about 15 percent by weight and about 55 percent by weight of calcium peroxide or between about 15 percent by weight and about 50 percent by weight of calcium peroxide.
Preferably, the combustible heat source comprises between about 20 percent by weight and about 65 percent by weight of calcium peroxide, between about 20 percent by weight and about 60 percent by weight of calcium peroxide, between about 20 percent by weight and about 55 percent by weight of calcium peroxide or between about 20 percent by weight and about 50 percent by weight of calcium peroxide.
More preferably, the combustible heat source comprises between about 30 percent by weight and about 65 percent by weight of calcium peroxide, between about 30 percent by weight and about 60 percent by weight of calcium peroxide, between about 30 percent by weight and about 55 percent by weight of calcium peroxide or between about 30 percent by weight and about 50 percent by weight of calcium peroxide.
The combustible heat source may comprise between about 40 percent by weight and about 65 percent by weight of calcium peroxide, between about 40 percent by weight and about 60 percent by weight of calcium peroxide, between about 40 percent by weight and about 55 percent by weight of calcium peroxide or between about 40 percent by weight and about 50 percent by weight of calcium peroxide.
The combustible heat source may comprise one or more binding agents.
As used herein with reference to the invention, the term “binding agent” is used to describe a component of the combustible heat source that is capable of binding other components of the combustible heat source together.
The combustible heat source may comprise one or more cellulosic binding agents.
The combustible heat source may comprise one or more non-cellulosic binding agents.
The combustible heat source may comprise at least about 3 percent by weight of the one or more binding agents.
Preferably, the combustible heat source comprises at least about 4 percent by weight of the one or more binding agents.
More preferably, the combustible heat source comprises at least about 5 percent by weight of the one or more binding agents.
The combustible heat source may comprise less than or equal to about 20 percent by weight of the one or more binding agents.
Preferably, the combustible heat source comprises less than or equal to about 15 percent by weight of the one or more binding agents.
More preferably, the combustible heat source comprises less than or equal to about 10 percent by weight of the one or more binding agents.
The combustible heat source may comprise between about 3 percent by weight and about 20 percent by weight of the one or more binding agents, between about 3 percent by weight and about 15 percent by weight of the one or more binding agents or between about 3 percent by weight and about 10 percent by weight of the one or more binding agents.
Preferably, the combustible heat source comprises between about 4 percent by weight and about 20 percent by weight of the one or more binding agents, between about 4 percent by weight and about 15 percent by weight of the one or more binding agents or between about 4 percent by weight and about 10 percent by weight of the one or more binding agents.
More preferably, the combustible heat source comprises between about 5 percent by weight and about 20 percent by weight of the one or more binding agents, between about 5 percent by weight and about 15 percent by weight of the one or more binding agents or between about 5 percent by weight and about 10 percent by weight of the one or more binding agents.
The combustible heat source may comprise one or more carboxylate burn salts.
As used herein with reference to the invention, the term “carboxylate burn salt” is used to describe a salt of a carboxylic acid other than carbonic acid. That is, as used herein with reference to the invention, the term “carboxylate burn salt” does not include carbonates or bicarbonates.
The one or more carboxylate burn salts may advantageously promote combustion of the combustible heat source.
The carboxylate burn salt may comprise a monovalent, divalent, or trivalent cation and a carboxylate anion.
The carboxylate burn salt may comprise a monovalent, divalent, or trivalent cation and an acetate, citrate or succinate anion.
The carboxylate burn salt may be an alkali metal carboxylate burn salt. For example, the carboxylate burn salt may be a sodium carboxylate burn salt or a potassium carboxylate burn salt.
The carboxylate burn salt may be an alkali metal acetate, an alkali metal citrate or an alkali metal succinate.
Most preferably, the carboxylate burn salt is potassium citrate.
The combustible heat source may comprise a single carboxylate burn salt.
The combustible heat source may comprise a combination of two or more different carboxylate burn salts. The two or more different carboxylate burn salts may comprise different carboxylate anions. The two or more different carboxylate burn salts may comprise different cations. For example, the combustible heat source may comprise a combination of an alkali metal citrate and an alkaline earth metal succinate.
The combustible heat source may comprise at least about 0.1 percent by weight of the one or more carboxylate burn salts.
The combustible heat source may comprise at least about 0.5 percent by weight of the one or more carboxylate burn salts.
Preferably, the combustible heat source comprises at least about 1 percent by weight of the one or more carboxylate burn salts.
The combustible heat source may comprise less than or equal to about 4 percent by weight of the one or more carboxylate burn salts.
Preferably, the combustible heat source comprises less than or equal to about 3 percent by weight of the one or more carboxylate burn salts.
The combustible heat source may comprise between about 0.1 percent by weight and about 4 percent by weight of the one or more carboxylate burn salts or between about 0.1 percent by weight and about 3 percent by weight of the one or more carboxylate burn salts.
The combustible heat source may comprise between about 0.5 percent by weight and about 4 percent by weight of the one or more carboxylate burn salts or between about 0.5 percent by weight and about 3 percent by weight of the one or more carboxylate burn salts.
Preferably, the combustible heat source comprises between about 1 percent by weight and about 4 percent by weight of the one or more carboxylate burn salts or between about 1 percent by weight and about 3 percent by weight of the one or more carboxylate burn salts.
The combustible heat source may be formed by: combining components of the combustible heat source to form a mixture; and forming the mixture into a desired shape.
For example, the combustible heat source may be formed by: combining one or more carbon materials, an oxidizing agent, one or more binding agents and any other components of the combustible heat source to form a mixture; and forming the mixture into a desired shape.
The components of the combustible heat source may be combined to form a mixture using suitable known methods such as, for example, dry granulation, wet granulation, high shear mixing, spheronization or extrusion.
The mixture may be formed into a desired shape using suitable known ceramic forming methods such as, for example, slip casting, extrusion, injection moulding, die compaction or pressing.
Preferably, the mixture is formed into a desired shape by a pressing process.
After formation the desired shape may be dried to reduce the moisture content thereof. The desired shape may be dried using suitable known methods. For example, the desired shape may be dried in an oven.
The combustible heat source may be a non-blind combustible heat source.
As used herein with reference to the invention, the term “non-blind” is used to describe a combustible heat source including at least one airflow channel extending along the length of the combustible heat source through which air may be drawn for inhalation by a user.
Preferably, the combustible heat source is a blind combustible heat source.
As used herein with reference to the invention, the term “blind” is used to describe a combustible heat source that does not include any airflow channels extending along the length of the combustible heat source through which air may be drawn for inhalation by a user.
The combustible heat source may comprise one or more closed or blocked channels through which air may not be drawn for inhalation by a user.
For example, the combustible heat source may comprise one or more closed channels that extend only part way along the length of the combustible heat source.
The inclusion of one or more closed channels may increase the surface area of the combustible heat source that is exposed to oxygen from the air. This may advantageously facilitate ignition and sustained combustion of the combustible heat source.
Reinforced combustible heat sources according to the invention comprise a non-combustible support embedded in the combustible heat source.
As used herein with reference to the invention, the term “non-combustible support” is used to describe a support that is substantially non-combustible at temperatures reached by the combustible heat source during ignition and combustion thereof.
The non-combustible support may be formed from any suitable material or combination of materials that are substantially non-combustible at temperatures reached by the combustible heat source during ignition and combustion thereof.
The non-combustible support may be formed from one or more materials having a melting point of greater than or equal to about 1200° C.
Preferably, the non-combustible support is formed from one or more materials having a melting point of greater than or equal to about 1300° C.
More preferably, the non-combustible support is formed from one or more materials having a melting point of greater than or equal to about 1400° C.
Preferably, the non-combustible support is formed from one or more metals, one or more alloys or a combination of one or more metals and one or more alloys.
The non-combustible support may be formed from one or more materials selected from the group consisting of chromium, iron, nickel and steel.
Preferably, the non-combustible support is formed from steel.
More preferably, the non-combustible support is formed from stainless steel.
The non-combustible support protrudes outwardly from the combustible heat source by a distance of less than or equal to 0.1 L, where L is the length of the combustible heat source.
The non-combustible support may protrude outwardly from the combustible heat source by a distance of less than or equal to 0.08 L, less than or equal to 0.06 L, less than or equal to about 0.04 L or less than or equal to about 0.02 L.
Preferably, the non-combustible support does not protrude outwardly from the combustible heat source.
The combustible heat source at least partially surrounds the non-combustible support.
Preferably, the combustible heat source completely surrounds the non-combustible support. In such embodiments, the non-combustible support is entirely enclosed within the combustible heat source.
Where the combustible heat source completely surrounds the non-combustible support, the non-combustible support advantageously does not affect the external appearance of the combustible heat source.
The non-combustible support may extend a distance of greater than or equal to about 0.3 L in the longitudinal direction within the combustible heat source.
Preferably, the non-combustible support extends a distance of greater than or equal to about 0.4 L within the combustible heat source.
The non-combustible support may extend a distance of greater than or equal to about 0.5 L within the combustible heat source.
The non-combustible support may extend a distance of less than or equal to about 1.0 L within the combustible heat source.
Preferably, the non-combustible support extends a distance of less than or equal to about 0.9 L within the combustible heat source.
The non-combustible support may extend a distance of less than or equal to about 0.8 L within the combustible heat source.
The non-combustible support may extend a distance of between about 0.3 L and about 1.0 L, between about 0.3 L and about 0.9 L or between about 0.3 L and about 0.8 L within the combustible heat source.
Preferably, the non-combustible support extends a distance of between about 0.4 L and about 1.0 L, between about 0.4 L and about 0.9 L or between about 0.4 L and about 0.8 L within the combustible heat source.
The non-combustible support may extend a distance of between about 0.5 L and about 1.0 L, between about 0.5 L and about 0.9 L or between about 0.5 L and about 0.8 L within the combustible heat source.
The total volume of the one or more non-combustible support elements relative to the volume of the combustible heat source may advantageously be chosen to improve the mechanical integrity of the combustible heat source while eliminating or reducing the impact of the non-combustible support on the generation of heat by the combustible heat source during combustion thereof.
The non-combustible support may comprise one or more non-combustible support elements.
The one or more combustible support elements may have any suitable shape.
Suitable shapes include, but are not limited to, coils, cones, cup-shapes, cubes, helices, pins, rectangular cuboids, rods, spirals and tubes.
The one or more combustible support elements may have any suitable size.
The one or more non-combustible support elements may have a length of greater than or equal to about 0.3 L.
Preferably, the one or more non-combustible support elements have a length of greater than or equal to about 0.4 L.
The one or more non-combustible support elements may have a length of greater than or equal to about 0.5 L or greater than or equal to about 0.6 L.
The one or more non-combustible support elements may have a length of less than or equal to about 1.1 L.
The one or more non-combustible support elements may have a length of less than or equal to about 1.0 L.
Preferably, the one or more non-combustible support elements have a length of less than or equal to about 0.9 L.
The one or more non-combustible support elements may have a length of less than or equal to about 0.8 L
The one or more non-combustible support elements may have a length of between about 0.3 L and about 1.1 L, between about 0.3 L and about 1.0 L, between about 0.3 L and about 1.0 L, between about 0.3 L and about 0.9 L or between about 0.3 L and about 0.8 L.
Preferably, the one or more non-combustible support elements have a length of between about 0.4 L and about 1.1 L. More preferably, the one or more non-combustible support elements have a length of between about 0.4 L and about 1.0 L. Most preferably, the one or more non-combustible support elements have a length of between about 0.4 L and about 0.9 L. For example, the one or more non-combustible support elements may have a length of between about 0.4 L and about 0.8 L.
The one or more non-combustible support elements may have a length of between about 0.5 L and about 1.1 L, between about 0.5 L and about 1.0 L, between about 0.5 L and about 1.0 L, between about 0.5 L and about 0.9 L or between about 0.5 L and about 0.8 L.
The one or more non-combustible support elements may have a length of between about 0.6 L and about 1.1 L, between about 0.6 L and about 1.0 L, between about 0.6 L and about 1.0 L, between about 0.6 L and about 0.9 L or between about 0.6 L and about 0.8 L.
The total volume of the one or more non-combustible support elements relative to the volume of the combustible heat source may advantageously be chosen to improve the mechanical integrity of the combustible heat source while eliminating or reducing the impact of the non-combustible support on the generation of heat by the combustible heat source during combustion thereof.
Preferably the total volume of the one or more non-combustible support elements is greater than or equal to about 0.00005V, where V is the volume of the combustible heat source.
The total volume of the one or more non-combustible support elements may be greater than or equal to about 0.0001V.
Preferably the total volume of the one or more non-combustible support elements is less than or equal to about 0.05V.
The total volume of the one or more non-combustible support elements may be less than or equal to about 0.025V.
The total volume of the one or more non-combustible support elements may be between about 0.00005V and about 0.05V or between about 0.00005V and about 0.025V.
The total volume of the one or more non-combustible support elements may be between about 0.0001V and about 0.05V or between about 0.0001V and about 0.025V.
The non-combustible support may comprise a single non-combustible support element.
For example, the non-combustible support may comprise a single elongate rod.
The non-combustible support may comprise a plurality of non-combustible support elements.
For example, the non-combustible support may comprise a plurality of elongate rods.
Where the non-combustible support comprises one or more elongate rods, the one or more elongate rods may have a diameter of between about 0.001 D and about 0.7 D, where D is the diameter of the combustible heat source.
Preferably the one or more elongate rods have a diameter of between about 0.01 D and about 0.3 D.
The non-combustible support may be formed from a mesh.
The mesh number of the mesh relative to the volume of the combustible heat source may advantageously be chosen to improve the mechanical integrity of the combustible heat source while eliminating or reducing the impact of the non-combustible support on the generation of heat by the combustible heat source during combustion thereof.
Where the non-combustible support is formed from a mesh, the mesh may have a US mesh size of between 20 and 150.
Preferably, the mesh has a US mesh number of between 50 and 100.
Where the non-combustible support is formed from a mesh, the mesh may be formed from strands or wires having a thickness of have a US mesh number of between about 20 microns to about 80 microns.
The mesh may be formed into any desired shape.
For example, the non-combustible support may comprise a cylindrical hollow tube formed from a mesh.
The non-combustible support may be embedded in the combustible heat source during formation of the combustible heat source.
For example, where the combustible heat source is formed by a pressing process, the non-combustible support and a mixture of the components of the combustible heat source may be placed in a mould and compressed together to form the reinforced heat source.
Aerosol-generating articles according to the invention comprise a reinforced heat source according to the invention and an aerosol-forming substrate.
As used herein with reference to the invention, the term “aerosol-forming substrate” is used to describe a substrate comprising aerosol-forming material capable of releasing upon heating volatile compounds, which can form an aerosol. The aerosols generated from aerosol-forming substrates of aerosol-generating articles according to the invention may be visible 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.
The aerosol-forming substrate may be in the form of a plug or segment comprising a material capable of releasing upon heating volatile compounds, which can form an aerosol, circumscribed by a wrapper. Where an aerosol-forming substrate is in the form of such a plug or segment, the entire plug or segment including the wrapper is considered to be the aerosol-forming substrate.
Preferably, the aerosol-forming substrate is downstream of the reinforced heat source. That is, the aerosol-forming substrate is preferably between the reinforced heat source and the distal end of the aerosol-generating article.
The aerosol-forming substrate may abut the reinforced heat source.
The aerosol-forming substrate may be longitudinally spaced-apart from the reinforced heat source.
Advantageously, the non-combustible support embedded in the combustible heat source of the reinforced heat source does not directly contact the aerosol-forming substrate. The absence of any direct contact between the non-combustible support and the aerosol-forming substrate may advantageously eliminate or reduce the impact of the non-combustible support on heat transfer from the combustible heat source to the aerosol-forming substrate during use of the aerosol-generating article.
Advantageously, the aerosol-forming substrate comprises aerosol-forming material comprising an aerosol-former.
The aerosol former may be any suitable compound or mixture of compounds that, in use, facilitates formation of a dense and stable aerosol and that is substantially resistant to thermal degradation at the operating temperature of the aerosol-generating article. Suitable aerosol formers are known in the art and include, but are not limited to: polyhydric alcohols, such as triethylene glycol, propylene glycol, 1,3-butanediol and glycerine; 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.
Advantageously, the aerosol former comprises one or more polyhydric alcohols.
More advantageously, the aerosol former comprises glycerine.
Preferably, the aerosol-forming substrate is a solid aerosol-forming substrate. The aerosol-forming substrate may comprise both solid and liquid components.
The aerosol-forming substrate may comprise plant-based material. The aerosol-forming substrate may comprise homogenised plant-based material.
The aerosol-forming substrate may comprise nicotine.
The aerosol-forming substrate may comprise tobacco material.
As used herein with reference to the invention, the term “tobacco material” is used to describe any material comprising tobacco, including, but not limited to, tobacco leaf, tobacco rib, tobacco stem, tobacco stalk, tobacco dust, expanded tobacco, reconstituted tobacco material and homogenised tobacco material.
The tobacco material may, for example, be in the form of powder, granules, pellets, shreds, strands, strips, sheets or any combination thereof.
Advantageously, the aerosol-forming substrate comprises homogenised tobacco material.
As used herein with reference to the invention, the term “homogenised tobacco material” is used to describe a material formed by agglomerating particulate tobacco.
In certain embodiments, the aerosol-forming substrate advantageously comprises a plurality of strands of homogenised tobacco material.
Advantageously, the plurality of strands of homogenised tobacco material may be aligned substantially parallel to one another within the aerosol-forming substrate.
In certain embodiments, the aerosol-forming substrate advantageously comprises a gathered sheet of homogenised tobacco material.
The aerosol-forming substrate may comprise a rod comprising a gathered sheet of homogenised tobacco material.
As used herein with reference to the aerosol-forming substrate of the invention, the term “rod” is used to describe a substantially cylindrical element of substantially circular, oval or elliptical cross-section.
As used herein with reference to the invention, the term “sheet” is used to describe a laminar element having a width and length substantially greater than the thickness thereof.
As used herein with reference to the invention, the term “gathered” is used to describe a sheet that is convoluted, folded, or otherwise compressed or constricted substantially transversely to the longitudinal axis of the aerosol-generating article.
The aerosol-forming substrate may comprise aerosol-forming material and a wrapper around and in contact with the aerosol-forming material.
The wrapper may be formed from any suitable sheet material that is capable of being wrapped around aerosol-forming material to form an aerosol-forming substrate.
In certain embodiments, the aerosol-forming substrate may comprise a rod comprising a gathered sheet of homogenised tobacco material and a wrapper around and in contact with the tobacco material.
In certain embodiments, the aerosol-forming substrate advantageously comprises a gathered textured sheet of homogenised tobacco material.
As used herein with reference to the invention, the term “textured sheet” is used to describe a sheet that has been crimped, embossed, debossed, perforated or otherwise deformed.
Use of a textured sheet of homogenised tobacco material may advantageously facilitate gathering of the sheet of homogenised tobacco material to form the aerosol-forming substrate.
The aerosol-forming substrate may comprise a gathered textured sheet of homogenised tobacco material comprising a plurality of spaced-apart indentations, protrusions, perforations or any combination thereof.
The aerosol-forming substrate may comprise a gathered crimped sheet of homogenised tobacco material.
As used herein with reference to the invention, the term “crimped sheet” is used to describe a sheet having a plurality of substantially parallel ridges or corrugations.
Advantageously, when an aerosol-generating article according to the invention comprising the aerosol-forming substrate has been assembled, the substantially parallel ridges or corrugations extend along or parallel to the longitudinal axis of the aerosol-generating article. This facilitates gathering of the crimped sheet of homogenised tobacco material to form the aerosol-forming substrate.
However, it will be appreciated that crimped sheets of homogenised tobacco material for inclusion in aerosol-forming substrates of aerosol-generating articles according to the invention may alternatively or in addition have a plurality of substantially parallel ridges or corrugations that are disposed at an acute or obtuse angle to the longitudinal axis of the aerosol-generating article when the aerosol-generating article has been assembled.
Preferably, the aerosol-forming substrate is substantially cylindrical.
The aerosol-forming substrate may have a length of between about 5 millimetres and about 20 millimetres.
Preferably, the aerosol-forming substrate has a length of between about 6 millimetres and about 15 millimetres.
More preferably, the aerosol-forming substrate has a length of between about 7 millimetres and about 12 millimetres.
The aerosol-forming substrate may have a diameter of between about 5 millimetres and about 15 millimetres.
Preferably, the aerosol-forming substrate has a diameter of between about 5 millimetres and about 10 millimetres
More preferably, the aerosol-forming substrate has a diameter of between about 7 millimetres and about 8 millimetres.
Where the combustible heat source is a non-blind combustible heat source, in use air drawn through the aerosol-generating article for inhalation by a user passes through at least one airflow channel along the length of the combustible heat source.
Where the combustible heat source is a non-blind combustible heat source, heating of the aerosol-forming substrate occurs by conduction and forced convection.
Where the combustible heat source is a blind combustible heat source, in use air drawn through the aerosol-generating article for inhalation by a user does not pass through any airflow channels along the length of the blind combustible heat source.
Where the combustible heat source is a blind combustible heat source, heating of the aerosol-forming substrate occurs primarily by conduction and heating of the aerosol-forming substrate by forced convection is minimised or reduced. Where the combustible heat source is a blind combustible heat source, it is particularly important to optimise the conductive heat transfer between the combustible heat source and the aerosol-forming substrate.
Where the combustible heat source is a blind combustible heat source, the lack of any airflow channels extending along the length of the combustible heat source through which air may be drawn for inhalation by a user may advantageously substantially prevent or inhibit activation of combustion of the combustible heat source during puffing by a user. This may advantageously substantially prevent or inhibit spikes in the temperature of the aerosol-forming substrate during puffing by a user.
By preventing or inhibiting activation of combustion of the combustible heat source, and so preventing or inhibiting excess temperature increases in the aerosol-forming substrate, combustion or pyrolysis of the aerosol-forming substrate under intense puffing regimes may be advantageously avoided. In addition, the impact of a user's puffing regime on the composition of the mainstream aerosol may be advantageously minimised or reduced.
Inclusion of a blind combustible heat source may advantageously substantially prevent or inhibit combustion and decomposition products and other materials formed during ignition and combustion of the combustible heat source from entering air drawn through the aerosol-generating article for inhalation by a user.
Where the combustible heat source is a blind combustible heat source, aerosol-generating articles according to the invention comprise one or more air inlets downstream of the combustible heat source for drawing air into the aerosol-generating article for inhalation by a user. Air drawn through the aerosol-generating article for inhalation by a user enters the aerosol-generating article through the one or more air inlets and not through the distal end of the aerosol-generating article.
Aerosol-generating articles according to the invention may comprise one or more air inlets around the periphery of the aerosol-forming substrate.
In such embodiments, during puffing by a user cool air is drawn into the aerosol-forming substrate of the aerosol-generating article through the one or more air inlets around the periphery of the aerosol-forming substrate. This may advantageously reduce the temperature of the aerosol-forming substrate and so substantially prevent or inhibit spikes in the temperature of the aerosol-forming substrate during puffing by a user.
As used herein with reference to the invention, the term “cool air” is used to describe ambient air that is not significantly heated by the combustible heat source upon puffing by a user.
By preventing or inhibiting spikes in the temperature of the aerosol-forming substrate, the inclusion of one or more air inlets around the periphery of the aerosol-forming substrate, may advantageously help to avoid or reduce combustion or pyrolysis of the aerosol-forming substrate under intense puffing regimes.
Inclusion of one or more air inlets around the periphery of the aerosol-forming substrate may advantageously help to minimise or reduce the impact of a user's puffing regime on the composition of the mainstream aerosol of the aerosol-generating article.
In certain preferred embodiments, aerosol-generating articles according to the invention may comprise one or more air inlets located proximate to a downstream end of the aerosol-forming substrate.
Aerosol-generating articles according to the invention may comprise one or more air inlets downstream of the aerosol-forming substrate. That is, one or more air inlets located between the aerosol-forming substrate and the proximal end of the aerosol-generating article.
Aerosol-generating articles according to the invention may comprise a reinforced heat source according to the invention, an aerosol-forming substrate and one or more other components.
The combustible heat source, the aerosol-forming substrate and, where included, the one or more other components of the aerosol-generating article may be assembled within one or more wrappers to form an elongate rod having a proximal end and an opposed distal end. Aerosol-generating articles according to the invention may thus resemble conventional lit-end cigarettes.
The one or more other components may comprise one or more of a cap, a transfer element or spacer element, an aerosol-cooling element or heat exchanger and a mouthpiece.
Aerosol-generating articles according to the invention may comprise a cap configured to at least partially cover a front portion of the reinforced heat source. The cap may be removable to expose the front portion of the reinforced heat source prior to use of the aerosol-generating article. The cap may advantageously protect the reinforced heat source prior to use of the aerosol-generating article.
As used herein with reference to the invention, the term “cap” is used to describe a protective cover at the distal end of the aerosol-generating article that substantially surrounds a front portion of the reinforced heat source.
For example, aerosol-generating articles according to the invention may comprise a removable cap attached at a line of weakness to the distal end of the aerosol-generating article, wherein the cap comprises a cylindrical plug of material circumscribed by a wrapper as described in WO 2014/086998 A1.
Aerosol-generating articles according to the invention may comprise one or more transfer elements or spacer elements.
Aerosol-generating articles according to the invention may comprise a transfer element or spacer element downstream of the aerosol-forming substrate. That is, a transfer element or spacer element located between the aerosol-forming substrate and the proximal end of the aerosol-generating article.
The transfer element may abut the aerosol-forming substrate. Alternatively, the transfer element may be longitudinally spaced-apart from the aerosol-forming substrate.
The inclusion of a transfer element may advantageously allow cooling of the aerosol generated by heat transfer from the combustible heat source to the aerosol-forming substrate.
The inclusion of a transfer element may advantageously allow the overall length of the aerosol-generating article to be adjusted to a desired value through an appropriate choice of the length of the transfer element. For example, the inclusion of a transfer element may allow the overall length of the aerosol-generating article to be adjusted to a length similar to that of a conventional cigarette.
The transfer element may have a length of between about 7 millimetres and about 50 millimetres. For example, the transfer element may have a length of between about 10 millimetres and about 45 millimetres or a length of between about 15 millimetres and about 30 millimetres.
The transfer element may have other lengths depending upon the desired overall length of the aerosol-generating article and the presence and length of other components within the aerosol-generating article.
The transfer element may comprise an open-ended tubular hollow body. In use, air drawn into the aerosol-generating article by a user may pass through the open-ended tubular hollow body as it passes downstream through the aerosol-generating article from the aerosol-forming substrate to the proximal end of the aerosol-generating article.
The open-ended tubular hollow body may be formed from one or more materials that are substantially thermally stable at the temperature of the aerosol generated by the transfer of heat from the combustible heat source to the aerosol-forming substrate. Suitable materials are known in the art and include, but are not limited to: paper; cardboard; thermoplastics, such a cellulose acetate; and ceramics.
Aerosol-generating articles according to the invention may comprise an aerosol-cooling element or heat exchanger downstream of the aerosol-forming substrate. That is, an aerosol-cooling element or heat exchanger located between the aerosol-forming substrate and the proximal end of the aerosol-generating article.
The aerosol-cooling element may advantageously cool the aerosol generated by heat transfer from the combustible heat source to the aerosol-forming substrate.
The aerosol-cooling element may comprise a plurality of longitudinally extending channels.
The aerosol-cooling element may comprise a gathered sheet of material selected from the group consisting of metallic foil, polymeric material, and substantially non-porous paper or cardboard.
The aerosol-cooling element may comprise a gathered sheet of material selected from the group consisting of polyethylene (PE), polypropylene (PP), polyvinylchloride (PVC), polyethylene terephthalate (PET), polylactic acid (PLA), cellulose acetate (CA), and aluminium foil.
The aerosol-cooling element may comprise a gathered sheet of biodegradable polymeric material, such as polylactic acid (PLA) or a grade of Mater-Bi® (a commercially available family of starch based copolyesters).
Where aerosol-generating articles according to the invention comprise a transfer element downstream of the aerosol-forming substrate and an aerosol-cooling element downstream of the aerosol-forming substrate, the aerosol-cooling element is preferably downstream of the transfer element. That is, the aerosol-cooling element is preferably located between the transfer element and the proximal end of the aerosol-generating article.
Aerosol-generating articles according to the invention may comprise a mouthpiece downstream of the aerosol-forming substrate. That is, a mouthpiece located between the aerosol-aerosol-forming and the proximal end of the aerosol-generating article.
Preferably, aerosol-generating articles according to the invention comprise a mouthpiece located at the proximal end of the aerosol-generating article.
The mouthpiece may be of low filtration efficiency or very low filtration efficiency.
The mouthpiece may be a single segment mouthpiece.
The mouthpiece may be a multi-segment mouthpiece.
The mouthpiece may comprise one or more segments comprising filtration material.
Suitable filtration materials are known in the art and include, but are not limited to, cellulose acetate and paper.
The mouthpiece may comprise one or more segments comprising absorbent material.
The mouthpiece may comprise one or more segments comprising adsorbent material.
Suitable absorbent materials and suitable adsorbent materials are known in the art and include, but are not limited to, activated carbon, silica gel and zeolites.
Aerosol-generating articles according to the invention may comprise one or more aerosol modifying agents downstream of the aerosol-forming substrate. For example, where included, one or more of the mouthpiece, aerosol-cooling element and transfer element of aerosol-generating articles according to the invention may comprise one or more aerosol modifying agents.
As used herein with reference to the invention, the term “aerosol-modifying agent” is used to describe an agent that, in use, modifies one or more features or properties of an aerosol generated by the aerosol-forming substrate of the aerosol-generating article.
Suitable aerosol-modifying agents include, but are not limited to, flavourants and chemesthetic agents.
As used herein with reference to the invention, the term “chemesthetic agent” is used to describe an agent that, in use, is perceived in the oral or olfactory cavities of a user by means other than, or in addition to, perception via taste receptor or olfactory receptor cells. Perception of chemesthetic agents is typically via a “trigeminal response,” either via the trigeminal nerve, glossopharyngeal nerve, the vagus nerve, or some combination of these. Typically, chemesthetic agents are perceived as hot, spicy, cooling, or soothing sensations.
Aerosol-generating articles according to the invention may comprise one or more aerosol modifying agents that are both a flavourant and a chemesthetic agent downstream of the aerosol-forming substrate. For example, where included, one or more of the mouthpiece, transfer element and aerosol-cooling element of aerosol-generating articles according to the invention may comprise menthol or another flavourant that provides a cooling chemesthetic effect.
Aerosol-generating articles according to the invention may comprise one or more heat-conducting elements.
Preferably, the aerosol-generating articles according to the invention comprise a heat-conducting element around at least a portion of the aerosol-forming substrate. The heat-conducting element may advantageously transfer heat to the periphery of the aerosol-forming substrate by conduction.
More preferably, aerosol-generating articles according to the invention comprise a heat-conducting element around and in contact with at least a portion of the aerosol-forming substrate. This may advantageously facilitate conductive heat transfer to the periphery of the aerosol-forming substrate.
The heat-conducting element may be around the entire length of the aerosol-forming substrate. That is, the heat-conducting element may overlie the entire length of the aerosol-forming substrate.
Preferably, the heat-conducting element is not around a rear portion of the aerosol-forming substrate. That is, the aerosol-forming substrate advantageously extends longitudinally beyond the heat-conducting element in a downstream direction.
Preferably, the aerosol-forming substrate extends longitudinally at least about 3 millimetres beyond the heat-conducting element in a downstream direction.
Preferably, aerosol-generating articles according to the invention comprise a heat-conducting element around at least a portion of the reinforced heat source and around at least a portion of the aerosol-forming substrate.
More preferably, aerosol-generating articles according to the invention comprise a heat-conducting element around at least a rear portion of the reinforced heat source and around at least a front portion of the aerosol-forming substrate.
Most preferably, aerosol-generating articles according to the invention comprise a heat-conducting element around and in contact with at least a rear portion of the reinforced heat source and around and in contact with at least a front portion of the aerosol-forming substrate.
The heat-conducting element may provide a thermal link between the reinforced heat source and the aerosol-forming substrate. This may advantageously help to facilitate adequate heat transfer from the combustible heat source to the aerosol-forming substrate to produce an acceptable aerosol.
Preferably, the rear portion of the reinforced heat source in contact with the heat-conducting element is between about 2 millimetres and about 8 millimetres in length.
More preferably, the rear portion of the reinforced heat source in contact with the heat-conducting element is between about 3 millimetres and about 5 millimetres in length.
Preferably, the heat-conducting element is non-combustible.
The heat conducting element may be oxygen restricting. In other words, the heat-conducting element may inhibit or resist the passage of oxygen through the heat-conducting element.
The heat-conducting element may be formed from any suitable thermally conductive material or combination of materials.
Preferably, the heat-conducting element comprises one or more heat-conductive materials having a bulk thermal conductivity of between about 10 W per metre Kelvin (W/(m·K)) and about 500 W per metre Kelvin (W/(m·K)), more preferably between about 15 W per metre Kelvin (W/(m·K)) and about 400 W per metre Kelvin (W/(m·K)), at 23 degrees Celsius and a relative humidity of 50 percent as measured using the modified transient plane source (MTPS) method.
Advantageously, the heat-conducting elements comprises one or more metals, one or more alloys or a combination of one or more metals and one or more alloys.
Suitable thermally conductive materials are known in the art and include, but are not limited to: metal foils, such as, for example, aluminium foil, iron foil and copper foil; and alloy foils, such as, for example, steel foil.
Advantageously, the heat-conducting element comprises aluminium foil.
Aerosol-generating articles according to the invention may comprise a non-combustible substantially air impermeable barrier between a rear end face of the reinforced heat source and the aerosol-forming substrate.
Inclusion of a non-combustible substantially air impermeable barrier between a rear end face of the reinforced heat source and the aerosol-forming substrate may advantageously limit the temperature to which the aerosol-forming substrate is exposed during ignition and combustion of the combustible heat source. This may help to avoid or reduce thermal degradation or combustion of the aerosol-forming substrate during use of the aerosol-generating article.
Inclusion of a non-combustible substantially air impermeable barrier between the rear end face of the reinforced heat source and the aerosol-forming substrate may advantageously substantially prevent or inhibit migration of components of the aerosol-forming substrate to the combustible heat source during storage and use of the aerosol-generating article.
The barrier may abut one or both of the rear end face of the reinforced heat source and the aerosol-forming substrate. Alternatively, the barrier may be longitudinally spaced apart from one or both of the rear end face of the reinforced heat source and the aerosol-forming substrate.
Where the combustible heat source does not completely surround the non-combustible support, the non-combustible support embedded in the combustible heat source may contact the barrier.
Advantageously, the barrier is adhered or otherwise affixed to the rear end face of the reinforced heat source.
Suitable methods for adhering or affixing a barrier to the rear end face of the reinforced heat source are known in the art and include, but are not limited to: spray-coating; vapour deposition; dipping; material transfer (for example, brushing or gluing); electrostatic deposition;
pressing; or any combination thereof.
The barrier between the rear end face of the reinforced heat source and the aerosol-forming substrate may have a low thermal conductivity or a high thermal conductivity. For example, the barrier may be formed from material having a bulk thermal conductivity of between about 0.1 W per metre Kelvin (W/(m·K)) and about 200 W per metre Kelvin (W/(m·K)), at 23 degrees Celsius and a relative humidity of 50 percent as measured using the modified transient plane source (MTPS) method.
The thickness of the barrier between the rear end face of the reinforced heat source and the aerosol-forming substrate may be selected to achieve good performance. For example, the barrier may have a thickness of between about 10 micrometres and about 500 micrometres.
The barrier between the rear end face of the reinforced heat source and the aerosol-forming substrate may be formed from one or more suitable materials that are substantially thermally stable and non-combustible at temperatures achieved by the combustible heat source during ignition and combustion thereof. Suitable materials are known in the art and include, but are not limited to: clays such as, for example, bentonite and kaolinite; glasses; minerals; ceramic materials; resins; metals; or any combination thereof.
Preferably, the barrier comprises aluminium foil.
A barrier of aluminium foil may be applied to the rear end face of the reinforced heat source by gluing or pressing it to the reinforced heat source. The barrier may be cut or otherwise machined so that the aluminium foil covers and adheres to at least substantially the entire rear end face of the reinforced heat source. Advantageously, the aluminium foil covers and adheres to the entire rear end face of the reinforced heat source.
Aerosol-generating articles according to the invention may have any desired length.
Preferably, aerosol-generating articles according to the invention may have a length of between about 65 millimetres and about 100 millimetres.
Aerosol-generating articles according to the invention may have any desired width.
Preferably, aerosol-generating articles according to the invention may have a width of between about 5 millimetres and about 12 millimetres.
Aerosol-generating articles according to the invention may be assembled using known methods and machinery.
For the avoidance of doubt, where applicable, features described above in relation to reinforced heat sources according to the invention may also be applied to aerosol-generating articles according to the invention and vice versa.
The invention will be further described, by way of example only, with reference to the accompanying drawings in which:
The aerosol-generating article 2 according to the embodiment of the invention shown in
As shown in
The aerosol-forming substrate 10 is located immediately downstream of the barrier 22 applied to the rear end face 8 of the reinforced heat source 4. The aerosol-forming substrate 10 comprises a gathered crimped sheet of homogenised tobacco material 24 and a wrapper 26 around and in direct contact with the gathered crimped sheet of homogenised tobacco material 24. The gathered crimped sheet of homogenised tobacco material 24 comprises an aerosol former such as, for example, glycerine.
The transfer element 12 is located immediately downstream of the aerosol-forming substrate 10 and comprises a cylindrical open-ended hollow cellulose acetate or cardboard tube 28.
The aerosol-cooling element 14 is located immediately downstream of the transfer element 12 and comprises a gathered sheet of biodegradable polymeric material such as, for example, polylactic acid.
The spacer element 16 is located immediately downstream of the aerosol-cooling element 14 and comprises a cylindrical open-ended hollow paper or cardboard tube.
In other embodiments of the invention (not shown), the aerosol-cooling element 14 and the spacer element 16 may be replaced by an additional transfer element comprising a cylindrical open-ended hollow cellulose acetate or cardboard tube.
The mouthpiece 18 is located immediately downstream of the spacer element 16. As shown in
The aerosol-generating article may further comprise a band of tipping paper (not shown) circumscribing a downstream end portion of the outer wrapper 20.
As shown in
In the aerosol-generating article 2 shown in
The aerosol-generating article 2 according to the embodiment of the invention shown in
As shown in
The combustible heat source 38 is a cylindrical carbonaceous heat source comprising carbon, an oxidizing agent such as, for example, an alkaline earth metal peroxide, and a binding agent. As shown in
The non-combustible support 40 comprises a single elongate rod 42 formed from a metal or alloy such as, for example, chromium, iron, nickel, steel, or stainless steel. As shown in
In use, a user ignites the combustible heat source 38. The oxidizing agent in the combustible heat source 38 promotes ignition and sustained combustion of the combustible heat source 38 through the release of oxygen. Once the combustible heat source 38 is ignited the user draws on the mouthpiece 18 of the aerosol-generating article 2. When a user draws on the mouthpiece 18, cool air (shown by dotted arrows in
The periphery of the front portion 10a of the aerosol-forming substrate 10 is heated by conduction through the rear end face 8 of the reinforced heat source 4 and the barrier 22 and through the heat-conducting element 34.
The heating of the aerosol-forming substrate 10 by conduction releases aerosol former and other volatile and semi-volatile compounds from the gathered crimped sheet of homogenised tobacco material 24. The compounds released from the aerosol-forming substrate 10 form an aerosol that is entrained in the air drawn into the aerosol-forming substrate 10 of the aerosol-generating article 2 through the air inlets 36 as it flows through the aerosol-forming substrate 10. The drawn air and entrained aerosol (shown by dashed arrows in
The non-combustible support 40 embedded in the combustible heat source 38 reinforces the combustible heat source 38 and advantageously prevents or reduces breakage of the combustible heat source 38 during use.
In each of the embodiments shown in
The non-combustible support 40 comprises a cylindrical open-ended hollow tube 44 formed from a mesh. The mesh may be formed from a metal or alloy such as, for example, chromium, iron, nickel, steel, or stainless steel. The cylindrical open-ended hollow tube 44 extends along the longitudinal axis of the combustible heat source 38.
In the reinforced heat sources 4 shown in
Reinforced heat sources according to the invention comprising a combustible heat source comprising carbon, calcium peroxide and a binding agent and a non-combustible support comprising a single elongate rod formed from stainless steel are produced having the construction shown in
Comparative heat sources not according to the invention are produced comprising a combustible heat source having the same composition and dimensions as the combustible heat source of the reinforced heat sources according to the invention. The comparative heat sources do not comprise a non-combustible support. Four comparative aerosol-generating articles not according to the invention comprising the comparative heat sources are produced having the same construction as the aerosol-generating articles according to the invention.
The reinforced heat sources of the four aerosol-generating articles according to the invention and the comparative heat sources of the four comparative aerosol-generating articles not according to the invention are ignited using a conventional yellow flame lighter.
No ‘fall-off’ or ‘drop-off’ of the reinforced heat sources of the four aerosol-generating articles according to the invention occurs during ignition or combustion of the reinforced heat sources.
By contrast, ‘fall-off’ or ‘drop-off’ of at least a portion of all of the comparative heat sources of the four aerosol-generating articles not according to the invention occurs during or shortly after ignition of the comparative heat sources.
The results demonstrate that inclusion of a non-combustible support embedded in the combustible heat source of reinforced heat sources according to the invention advantageously improves the mechanical integrity of reinforced heat sources according to the invention.
The specific embodiments and examples described above illustrate but do not limit the invention. It is to be understood that other embodiments of the invention may be made and the specific embodiments and examples described herein are not exhaustive.
Claims
1. A reinforced heat source for an aerosol-generating article, the reinforced heat source comprising:
- a blind combustible heat source having a length L; and
- a non-combustible support embedded in the combustible heat source, wherein the non-combustible support does not protrude outwardly from the combustible heat source.
2. A reinforced heat source according to claim 1 wherein the combustible heat source completely surrounds the non-combustible support.
3. A reinforced heat source according to claim 1 wherein the non-combustible support extends a distance of between about 0.4 L and about 0.9 L within the combustible heat source.
4. A reinforced heat source according to claim 1 wherein the non-combustible support is formed from one or more materials having a melting point of greater than or equal to about 1300° C.
5. A reinforced heat source according to claim 1 wherein the non-combustible support is formed from one or materials selected from the group consisting of chromium, iron, nickel and steel.
6. A reinforced heat source according to claim 1 wherein the non-combustible support comprises one or more non-combustible support elements.
7. A reinforced heat source according to claim 6 wherein the one or more non-combustible support elements have a length of between about 0.4 L and about 0.9 L.
8. A reinforced heat source according to claim 6 wherein the combustible heat source has a volume V and the total volume of the one or more non-combustible support elements is between about 0.00005V and about 0.05V.
9. A reinforced heat source according to claim 1 wherein the non-combustible support comprises one or more elongate rods.
10. A reinforced heat source according to claim 9 wherein the combustible heat source has a diameter D and the one or more elongate rods have a diameter of between about 0.01 D and about 0.3 D.
11. A reinforced heat source according to claim 1 wherein the non-combustible support is formed from a mesh.
12. A reinforced heat source according to claim 1 wherein the combustible heat source comprises an oxidizing agent.
13. A reinforced heat source according to claim 12 wherein the oxidizing agent is an alkaline earth metal peroxide.
14. A reinforced heat source according to claim 12 wherein the oxidizing agent is calcium peroxide.
15. An aerosol-generating article comprising:
- a reinforced heat source according to claim 1; and
- an aerosol-generating substrate.
Type: Application
Filed: Jun 14, 2021
Publication Date: Aug 3, 2023
Inventors: Robert Emmett (Neuchatel), Houxue Huang (Neuchatel)
Application Number: 18/010,111
