RU2841323C2 - Smoking article and method of reducing excessive heating therein - Google Patents

Abstract

FIELD: smoking accessories.

SUBSTANCE: group of inventions relates to a smoking article and a method for reducing excessive heating in it. Smoking article comprises an outer wrapper surrounding at least a portion of the smoking article, a tobacco material, filter located downstream of the tobacco material and near the mouth end of the smoking article, and an energy absorber arranged so that at least a portion of the energy absorber is mixed with the tobacco material, or such that the energy absorber is completely mixed with the tobacco material. Energy absorber is a thermal energy absorber designed to increase uniform distribution of heated air over the tobacco material.

EFFECT: control of distribution of heated air in tobacco material is provided, degree of overheating or pyrolysis in smoking products is reduced and thus negative effects associated with overheating of tobacco materials in smoking products are reduced.

23 cl, 7 dwg

Description

AREA OF TECHNOLOGY

The present invention relates to smoking articles, sometimes referred to as tobacco heating products, capable of heating tobacco materials without burning the tobacco materials contained in the tobacco heating products.

LEVEL OF TECHNOLOGY

Over the years, a variety of smoking articles have been proposed as improvements to or alternatives to smoking products that rely on the combustion of tobacco for use. Some exemplary alternatives include devices in which solid or liquid fuels are burned to impart heat to the tobacco. Such devices, commonly referred to as smoking articles or tobacco heating products, allow the heating of tobacco materials without significantly burning or combusting the tobacco material. The intent of improvements to or alternatives to smoking articles has typically been to provide the sensations associated with smoking cigarettes, cigars, or pipes, but without delivering significant amounts of incomplete combustion and pyrolysis products that may be harmful to the user. See, for example, the various alternative smoking articles, aerosol delivery devices, and heat generating sources set forth in U.S. Patent No. 7,726,320 to Robinson et al., U.S. Patent Application Publication No. 2013/0255702 to Griffith Jr., and U.S. Patent Application Publication No. 2013/0255702 to Griffith Jr. et al., in U.S. Patent Application Publication No. 2014/0096781 to Sears et al. and in U.S. Patent Application Publication No. 2015/0216232 to Bless et al., which are incorporated herein by reference.

Products that produce the taste and sensation of smoking by heating tobacco, tobacco-derived materials, or other plant-derived materials without significant combustion or burning have inappropriate and harmful performance characteristics. For example, overheating tobacco heating products may result in unwanted overburning or combustion of the internal tobacco materials, which may be harmful to the user. Accordingly, it may be preferable to provide a smoking article that can provide the sensation of smoking cigarettes, cigars, or pipes without overheating the tobacco material and with improved performance characteristics.

DISCLOSURE OF THE ESSENCE OF THE INVENTION

The present invention relates to thermal energy absorbers for smoking articles, such as/sometimes referred to as tobacco heating products. In various embodiments, a smoking article may comprise an outer wrapper surrounding at least a portion of the smoking article, the smoking article being defined by an upstream ignition end and a downstream mouthpiece end, a carbon-based heat source located near the ignition end, a tobacco material located downstream of the carbon-based heat source, and a thermal energy absorber at least partially located between the tobacco material and the carbon-based heat source. In some embodiments, the thermal energy absorber may comprise a metal or ceramic material. In some embodiments, the thermal energy absorber may be aluminum or an aluminum oxide material. In various embodiments, the thermal energy absorber is configured to increase the uniform distribution of heated air across the tobacco material.

In specific embodiments, the thermal energy absorber is made in the form of one or more circular disks. In some embodiments, one or more circular disks have an individual diameter of about 5 mm to about 9 mm and a thickness of about 0.1 mm to about 4 mm. In specific embodiments, one or more circular disks may contain a plurality of holes. In various other embodiments, the plurality of holes may have an irregular shape, be randomly distributed, or be distributed according to a pattern.

In particular embodiments, the thermal energy absorber may be in the form of a plurality of particles. In some embodiments, the particles have a substantially spherical shape or a hollow sphere shape. In some embodiments, the thermal energy absorber may contain from about 3 to about 500 particles. In various embodiments, the particles may have a diameter from about 0.1 mm to about 5 mm. In some embodiments, the thermal energy absorber comprises a material with a specific heat capacity from about 0.1 kJ/(kg⋅K) to about 3 kJ/(kg⋅K).

In various embodiments, the tobacco material may also include one or more of a tobacco extract, an aerosol precursor composition, and a flavoring agent. In some embodiments, the tobacco material may be in ground or particulate form. In some embodiments, the carbon-based heat source may have a plurality of air inlets extending longitudinally therethrough. In various embodiments, the thermal energy absorber may be configured to reduce the maximum temperature of the smoking article by an amount from about 25°C to about 75°C and from about 475°C to about 525°C. In some such embodiments, the thermal energy absorber may be configured to reduce by an amount from about 50°C to about 500°C. In some embodiments, the thermal energy absorber may be configured to reduce the total amount of particulate matter (TPM) released during smoking of the smoking article. In some other embodiments, the downstream mouth end may also comprise a filter material.

Some embodiments provide a method for reducing excess heat in a smoking article, wherein the method may include: providing a smoking article that comprises a carbon-based heat source, a tobacco material, a thermal energy absorber, and an outer wrapper surrounding at least a portion of the smoking article, wherein the smoking article is defined by an upstream ignition end and a downstream mouthpiece end; and arranging the thermal energy absorber at least partially between the tobacco material and the carbon-based heat source such that the maximum temperature of the smoking article is reduced by an amount from about 50°C to about 500°C upon ignition of the carbon-based heat source. In some embodiments, the thermal energy absorber may be configured to increase the uniform distribution of heated air across the tobacco material. In some embodiments, the thermal energy absorber may be configured to reduce the total amount of particulate matter (TPM) released during smoking of the smoking article. In some other embodiments, the downstream mouthpiece end may also comprise a filter material.

The present disclosure includes, without limitation, the following embodiments.

Embodiment 1: A smoking article comprising an outer wrapper surrounding at least a portion of the smoking article, wherein the smoking article is defined by an upstream ignition end and a downstream mouthpiece end; a carbon-based heat source located near the ignition end; a tobacco material located downstream from the carbon-based heat source; and a thermal energy absorber at least partially located between the tobacco material and the carbon-based heat source.

Implementation option 2: A smoking article according to embodiment 1, in which the thermal energy absorber comprises one or more metallic or ceramic materials.

Embodiment 3: A smoking article according to any of embodiments 1-2, wherein the thermal energy absorber comprises one or more aluminum or aluminum oxide material.

Implementation option 4: A smoking article according to any of implementation options 1-3, in which the thermal energy absorber is designed with the possibility of increasing the uniform distribution of heated air over the tobacco material.

Implementation option 5: A smoking article according to any of the implementation options 1-4, in which the thermal energy absorber is made in the form of one or more round disks.

Embodiment 6: A smoking article according to any one of embodiments 1-5, wherein one or more circular discs have an individual diameter from about 5 mm to about 9 mm and a thickness from about 0.1 mm to about 4 mm.

Embodiment 7: A smoking article according to any of embodiments 1-6, wherein one or more circular discs contain a plurality of holes.

Embodiment 8: A smoking article according to any of embodiments 1-7, wherein the plurality of holes are irregularly shaped, randomly distributed, or distributed according to a pattern.

Implementation variant 9: A smoking article according to any of the implementation variants 1-4, in which the thermal energy absorber is made in the form of a plurality of particles.

Embodiment 10: A smoking article according to any of embodiments 1-4 and 9, wherein the particles have a substantially spherical shape.

Embodiment 11: A smoking article according to any one of embodiments 1-4 and 9-10, wherein the thermal energy absorber comprises from about 3 to about 500 particles.

Embodiment 12: A smoking article according to any one of embodiments 1-4 and 9-11, wherein the particles have a diameter of from about 0.005 mm to about 5 mm.

Embodiment 13: A smoking article according to any one of embodiments 1-12, wherein the thermal energy absorber comprises a material with a specific heat capacity from about 0.1 kJ/(kg⋅K) to about 3 kJ/(kg⋅K).

Embodiment 14: A smoking article according to any one of embodiments 1-13, wherein the tobacco material also includes one or more of a tobacco extract, an aerosol precursor composition, and a flavoring agent.

Embodiment 15: A smoking article according to any of embodiments 1-14, wherein the tobacco material is in one or more of ground or particulate forms.

Embodiment 16: A smoking article according to any one of embodiments 1-15, wherein the carbon-based heat source has a plurality of air inlet openings passing through it in a longitudinal direction.

Embodiment 17: A smoking article according to any of embodiments 1-16, wherein the thermal energy absorber is designed to reduce the maximum temperature of the smoking article by an amount from about 50°C to about 500°C.

Embodiment 18: A smoking article according to any of embodiments 1-17, in which the downstream mouthpiece end also contains filter material.

Embodiment 19: A method for reducing excess heat in a smoking article, comprising providing a smoking article that comprises a carbon-based heat source, tobacco material, a thermal energy absorber, and an outer wrapper surrounding at least a portion of the smoking article, wherein the smoking article is defined by an upstream ignition end and a downstream mouthpiece end; and arranging the thermal energy absorber at least partially between the tobacco material and the carbon-based heat source such that the maximum temperature of the smoking article is reduced by an amount from about 50°C to about 500°C upon ignition of the carbon-based heat source.

Implementation variant 20: The method according to implementation variant 19, according to which the thermal energy absorber is designed with the possibility of increasing the uniform distribution of heated air over the tobacco material.

Embodiment 21: The method according to any of embodiments 19-20, according to which the downstream mouthpiece end also contains filter material.

These and other features, aspects and advantages of the disclosure will become apparent from reading the following detailed description in conjunction with the accompanying drawings, which are briefly described below. The present invention includes any combination of two, three, four or more of the above embodiments, as well as combinations of two, three, four or more features or elements set forth in the present description, regardless of whether such features or elements are explicitly combined in the description of a particular embodiment herein. The present disclosure is intended to be read as a whole, such that any individual features or elements of the disclosed invention in any of its various aspects and embodiments should be considered as combinable unless the context clearly dictates otherwise.

BRIEF DESCRIPTION OF DRAWINGS

Having thus described the aspects of this disclosure in the general terms set forth above, reference is now made to the accompanying drawings, which are not necessarily drawn to scale, and in which:

FIG. 1 is a partial cross-sectional view of a smoking article according to an exemplary embodiment of the present disclosure, including a heat source, a tobacco material, and a thermal energy absorber;

FIG. 2 is a partial cross-sectional view of an upstream ignition end of a smoking article according to an exemplary embodiment of the present disclosure, including a heat source holder;

FIG. 3 is a partial cross-sectional view of a thermal energy absorber according to an exemplary embodiment of the present disclosure;

FIG. 4 is a partial cross-sectional view of a smoking article according to an exemplary embodiment of the present disclosure, including thermal energy absorbers in the form of a plurality of particles;

FIG. 5 is a graph showing average maximum temperature profiles for smoking articles without thermal energy absorbers and smoking articles including thermal energy absorbers, according to exemplary embodiments of the present disclosure;

FIG. 6 is a graph showing average pressure drop profiles for smoking articles without thermal energy absorbers, according to exemplary embodiments of the present disclosure;

FIG. 7 is a graph showing the total particulate matter (TPM) released during smoking of smoking articles with and without thermal energy absorbers, according to exemplary embodiments of the present disclosure.

IMPLEMENTATION OF THE INVENTION

The present disclosure will now be described more fully with reference to exemplary embodiments thereof. These exemplary embodiments are described in such a way that the present disclosure thoroughly, completely and fully conveys the scope of the invention to one skilled in the art. Of course, the present invention can be implemented in many different forms and should not be considered limited to the embodiments described herein; on the contrary, these embodiments are presented so that the present invention satisfies the relevant legal requirements. In the present disclosure and in the appended claims, grammatical constructions indicating the singular also imply the plural, unless the context of the invention clearly dictates otherwise. In addition, although reference may be made herein to quantities, values, geometric relationships or the like, unless otherwise indicated, any one or more, if not all, of them may be absolute or approximate in order to account for reasonable variations that may occur, for example, due to technical tolerances or the like.

As described below, exemplary embodiments of the present disclosure relate to thermal energy absorbers for use in smoking articles, such as/sometimes referred to as heated tobacco products. The use of thermal energy absorbers can prevent overheating of smoking articles, which causes unwanted overburning/combustion of internal tobacco materials and charring of the tipping paper of cigarette rods. In addition, overheating of smoking articles can contribute to negative organoleptic properties and lead to the release of certain components from the tobacco materials. Many components of tobacco cigarette smoke are products of incomplete combustion (pyrolysis) and thermogenic degradation of tobacco cigarettes as a result of heating (thermogenic degradation). Typical markers of pyrolysis and thermogenic degradation of tobacco cigarettes include acetaldehyde, benzoapyrene and carbon monoxide. The use of thermal energy absorbers located downstream of the carbon-based heat source may serve to reduce the degree of overheating or pyrolysis in smoking articles and thus reduce the negative effects associated with overheating of tobacco materials in smoking articles.

Some embodiments of smoking articles according to the present disclosure use a flammable heat source to heat a material (preferably without burning the material to any significant extent) to form an inhalable substance (e.g., carbon-heated tobacco products). Preferably, the material is heated without burning the material to any significant extent. The components of such systems are in the form of articles that are substantially compact so as to be considered portable devices. In other words, use of the components of the preferred smoking articles does not result in the formation of smoke in the sense that the aerosol is primarily derived from by-products of combustion or pyrolysis of tobacco, but instead, use of said preferred systems results in the formation of vapors resulting from heating, without combustion or burning, of the tobacco included therein. In some exemplary embodiments, the smoking article components may be characterized as heated-but-not-combusted cigarettes, and these heated-but-not-combusted cigarettes most preferably include tobacco and/or tobacco-derived components and thus deliver tobacco-derived components in the form of an aerosol.

Smoking articles can provide a variety of sensations (e.g., inhalation and exhalation rituals, types of tastes and aromas, organoleptic effects, physical sensation, rituals of use, visual cues such as those provided by a visible aerosol, and the like) of smoking a cigarette, cigar or smoking pipe that are caused by lighting and burning tobacco (and then inhaling tobacco smoke) without burning any of their components to any significant extent. For example, a user of smoking articles according to some example embodiments of the disclosure of the present invention can hold and use this component in a similar way to a smoker using a smoking article of a traditional type, by inhaling through one end of said means for inhaling an aerosol formed by this means, performing or performing puffs at selected intervals of time, and the like.

Although the systems are generally described herein in terms of embodiments related to smoking articles, it should be understood that the mechanisms, components, features and methods can be implemented in a variety of different forms and associated with different articles. For example, the description provided herein can be used in conjunction with embodiments of traditional smoking articles (e.g., cigarettes, cigars, pipes, etc.), cigarettes that use heating tobacco instead of burning it, and corresponding packaging for any of the products described herein. Accordingly, it should be understood that the description of the mechanisms, components, elements and methods disclosed herein are presented with respect to embodiments of the invention related to smoking articles solely by way of example and can be implemented and used in various other products and methods.

The smoking articles of the present disclosure may also be characterized as vapor-generating articles or drug delivery articles. Thus, such articles or devices may be adapted to deliver one or more substances (e.g., flavorings and/or pharmaceutical active ingredients) in a form or state suitable for inhalation. For example, the inhalable substances may be substantially in the form of a vapor (e.g., a substance that is in the gaseous phase at a temperature below its critical point). Alternatively, the inhalable substances may be in the form of an aerosol (i.e., a suspension of fine solid particles or liquid droplets in a gas). For simplicity, the term "aerosol" as used herein is intended to refer to vapors, gases, and aerosols of a form or type that are suitable for inhalation by a person, whether or not they are visible and whether or not they have a form that can be considered "smoke-like." The physical form of the respirable substance is not necessarily limited by the nature of the devices of the invention, but rather may depend on the nature of the substance and the respirable substance itself, whether the substance is in a vapor state or in an aerosol state. In some embodiments, the terms "vapor" and "aerosol" may be interchangeable. Thus, for simplicity, the terms "vapor" and "aerosol" used to describe aspects of the invention should be understood as interchangeable, unless otherwise indicated.

In some embodiments, the smoking articles of the present disclosure may comprise an outer wrapper surrounding at least a portion of the smoking article, the smoking article being defined by an upstream ignition end and a downstream mouth end, a heat source located near the ignition end, a tobacco material located downstream of the heat source and spatially separated from the mouth end of the smoking article, and at least one thermal energy absorber at least partially located between the tobacco material and the carbon-based heat source. Alternative formats, configurations and arrangements of various thermal energy absorbers, smoking articles and components within the smoking articles of the present disclosure will be apparent in light of the further disclosure provided below.

In this regard, FIG. 1 shows a smoking article 100 according to an exemplary embodiment of the present disclosure. The smoking article 100 may include an outer wrapper 102 surrounding at least a portion of the smoking article 100, wherein the smoking article is defined by an upstream ignition end 104 and a downstream mouthpiece end 106. In some embodiments, the smoking article 100 may also include a heat source 108, tobacco material 110, and a heat absorber 112. In some embodiments, the heat source 108 may be located near the ignition end 104. In particular embodiments, the tobacco material 110 may be located downstream of the carbon-based heat source 108 and, if necessary, spatially separated from the mouth end 106 of the smoking article 100. In some embodiments, the thermal energy absorber 112 may be at least partially located between the tobacco material 110 and the heat source 108.

In various embodiments, smoking articles according to the present disclosure may take various general shapes, including, but not limited to, a general shape that may be defined as a substantially rod-shaped or substantially tubular shape or a substantially cylindrical shape. In the embodiment of FIG. 1, smoking article 100 has a substantially circular cross-section, however, other cross-sectional shapes (e.g., oval, square, triangle, etc.) are also encompassed by the present disclosure. Thus, such language that describes the physical shape of the article may also be applied to its individual components.

In various embodiments, the alignment of the components in the smoking article of the present disclosure may vary. In some embodiments, the thermal energy absorber may be located entirely between the heat source and the tobacco material. In some other embodiments, at least a portion of the thermal energy absorber may be mixed with the tobacco material such that the thermal energy absorber may be located only partially between the heat source and the tobacco material. Other configurations are not necessarily excluded, for example, the thermal energy absorber may be completely mixed within the tobacco material such that the thermal energy absorber is not located between the heat source and the tobacco material. In general, the heat source may be located close enough to the tobacco material such that heat from the heat source can heat, without combustion or burning, the tobacco material (and in some embodiments, one or more flavors, medications, etc., which may also be provided for delivery to the user) and form an aerosol for delivery to the user.

Additional components may be used in the smoking article of the present disclosure, for example, with reference to FIG. 1, the smoking article 100 may include a filter 114 located downstream of the tobacco material 110 and proximate the downstream mouth end 106 of the smoking article 100. In various embodiments, the filter 114 may be made of cellulose acetate or polypropylene material. The filter 114 may additionally or alternatively comprise strands of a tobacco-containing material as described in U.S. Patent No. 5,025,814 to Raker et al., which is incorporated herein by reference in its entirety. In various embodiments, the filter 114 may increase the structural integrity of the mouth end of the smoking article 100 and/or provide filtration capacity, if desired, and/or provide draw resistance. In some embodiments, the filter may comprise separate parts. For example, some embodiments may include a portion providing filtration, a portion providing draw resistance, a hollow portion providing a space for cooling the aerosol, a portion providing increased structural integrity, other portions of the filter, or any one or any combination of the above. In various other embodiments, components in addition to the filter 114 may exist between the tobacco material 110 and the mouth end 106 of the smoking article 100. For example, in some embodiments, one or any combination of the following may be located between the tobacco material 110 and the mouth end 106 of the smoking article 100: an air gap; a hollow tubular structure; phase change materials for cooling the air; a means for releasing aroma; ion exchange fibers capable of selective chemical adsorption; aerogel particles as a filter medium and other suitable materials. Some examples of possible phase change materials include, but are not limited to, salts such as AgNO3, AlCl3, TaCl3, InCl3, SnCl2, AlI3, and TiI4; metals and metal alloys such as selenium, tin, indium, tin-zinc, indium-zinc, or indium-bismuth; and organic compounds such as D-mannitol, succinic acid, p-nitrobenzoic acid, hydroquinone, and adipic acid. Other examples are described in U.S. Patent No. 8,430,106 to Potter et al., which is incorporated herein by reference in its entirety.

As noted above, in various embodiments, the smoking article 100 may comprise an outer wrapper 102 surrounding at least a portion of the smoking article 100. In some embodiments, the wrapper material of the outer wrapper 102 may comprise a material that resists heat transfer, which may include paper or another fibrous material, such as a cellulosic material. The wrapper material used as an outer wrapper to confine smoking articles may vary. Examples of types of wrapper materials are set forth in U.S. Patent Nos. 4,938,238 to Barnes et al. and 5,105,837 to Barnes et al. Wrapper materials, such as those set forth in U.S. Patent Application Publication No. 2005/0005947 to Hampl, Jr. and in PCT Application Publication WO 2005/039326 to Rasouli et al., may be used as inner wrap materials in a so-called "double wrap" configuration. An exemplary type of thermally conductive wrap material is disclosed in U.S. Patent No. 5,551,451 to Riggs et al., and other suitable wrap materials are disclosed in U.S. Patent Nos. 5,065,776 to Lawson et al. and 6,367,481 to Nichols et al., each of which is incorporated herein by reference. Examples of wrapping materials, such as laminates of paper and metal foil, and paper used as an outer wrapper enclosing a heat-generating portion, have been included in types of cigarettes sold under the trademarks "Premier" and "Eclipse" manufactured by R. J. Reynolds Tobacco Company. Other representative wrapping materials and processed wrapping materials suitable for use in the manufacture of cigarettes are set forth in U.S. Patents 5,220,930 to Gentry; 6,976,493 to Chapman et al.; and 7,047,982 to Seymour et al.; and U.S. patent application Ser. No. 11/377,630, filed March 16, 2006, to Crooks et al.; each of which is incorporated herein by reference. The outer wrapper 102 may also include at least one filler material embedded in or dispersed in the fibrous material. In various embodiments, the filler material may be in the form of water-insoluble particles. Additionally, the filler material may include inorganic components. In various embodiments, the outer wrapper may be formed from a plurality of layers, such as an underlying layer, a bulk layer, and an overlying layer, such as a typical wrapping paper in a cigarette. Such materials may include, for example, a lightweight waste fibrous mass, such as flax, hemp, sisal, rice stalks, and/or esparto. The outer wrapper 102 may also include a material typically used in a filter element of a conventional cigarette, such as cellulose acetate.

In some embodiments, the outer wrapper 102 may also comprise a heat source holder 120 located at least near the ignition end 104 of the smoking article 100. In various embodiments, the heat source holder 120 may surround the heat source 108 at the near end 120a of the heat source holder 120 and the heat energy absorber 112 at the far end 120b of the heat source holder 120, as shown in FIG. 2. In various embodiments, the heat source holder 120 may have a certain degree of heat resistance and may substantially have a tubular shape. In some embodiments, the heat source holder 120 may hold the heat source 108 such that a predetermined length of the heat source 108 projects from the near end of the heat source holder 120. In particular embodiments, the heat source holder 120 may have a peripheral wall with a layered structure and a plurality of layers. For example, the peripheral wall may include one or more multilayer layers, metal layers, and paper layers bonded together. In particular embodiments, one or more metal layers may be included in the heat source holder 120 such that when the carbon-based heat source 108 burns and the outer wrapper 102 is heated by the heat of the carbon-based heat source 108, the one or more metal layers maintain a heating temperature of the outer wrapper 102 below the combustion temperature of the outer wrapper 102. Examples of heat source holders for carbon-based heat sources are described in U.S. Patent Application Publication No. 2018/0317560 to Shinozaki et al., the disclosure of which is incorporated herein by reference in its entirety.

Referring again to FIG. 1, in various embodiments, the smoking article 100 may comprise a heat source 108 located near the ignition end 104. In particular embodiments, the carbon-based heat source 108 may include combustible carbonaceous materials of various types. In particular other embodiments, the carbon-based heat source 108 may include non-combustible additives in addition to the combustible carbonaceous materials. Examples of carbon-based heat sources are described in U.S. Patent Application Publication No. 2018/0317560 to Shinozaki et al., which is incorporated herein by reference in its entirety. In some embodiments, the carbon-based heat source 108 may include other elements in addition to combustible carbonaceous materials (e.g., tobacco components such as powdered tobaccos or tobacco extracts; flavoring agents; salts such as sodium chloride, potassium chloride, and sodium carbonate; aluminum oxide granules; ammonia sources such as ammonia salts; and/or binding agents such as guar gum, ammonium alginate, and sodium alginate).

Although the specific dimensions of the applicable carbon-based heat sources 108 may vary, in some embodiments, the carbon-based heat source 108 may have a length in the range of about 5 mm to about 20 mm inclusive, or about 8 mm to about 16 mm, or about 12 mm, and an overall diameter in the range of about 3 mm to about 8 mm inclusive. In some embodiments, the carbon-based heat source 108 may extend a predetermined length from the ignition end 104, as shown in FIG. 1. Referring again to FIG. 2, in certain other embodiments, the carbon-based heat source 108 may extend a predetermined length from the proximal end 120a of the heat source holder 120. The predetermined length may vary, in some embodiments, the predetermined length may have a length in the range of about 2 mm to about 12 mm inclusive, or about 6 mm to about 10 mm inclusive, or about 8 mm. Although in other embodiments the carbon-based heat source 108 may be formed in various ways, in the embodiment shown the carbon-based heat source 108 is extruded or mixed using ground or powdered carbon-based material, and the carbon-based heat source 108 has a density that is greater than about 0.5 g/cm3, often greater than about 0.7 g/cm3, and often greater than about 1 g/cm3, on a dry weight basis. See, for example, the types of components, compositions and designs of fuel sources that are set forth in U.S. Patent No. 5,551,451 to Riggs et al. and U.S. Patent No. 7,836,897 to Borschke et al., which are incorporated herein by reference in their entireties. Although in various embodiments the carbon-based heat source 108 may have various shapes, including, for example, a substantially solid cylindrical shape or a hollow cylindrical (e.g. tubular) shape, the carbon-based heat source 108 of the embodiment shown comprises an extruded monolithic carbonaceous material that has a generally cylindrical shape, but with a plurality of air inlets extending therethrough in the longitudinal direction. The air inlets may have various other shapes or a substantially identical shape, and in some embodiments the plurality of air inlets may be arranged in a pattern or randomly distributed over the surface of the carbon-based heat source and extend therethrough in the longitudinal direction. In some embodiments the smoking article 100 and, in particular, the carbon-based heat source 108 may also include a heat transfer component. In various embodiments the heat transfer component may be located near the carbon heat source 108, and in some embodiments the heat transfer component may be located in or inside the carbon heat source 108. Some examples of heat transfer components are described in U.S. Patent Application Ser. No. 15/923,735, filed March 16, 2018, entitled Smoking Article with Heat Transfer Component, which is incorporated herein by reference in its entirety.

In general, the carbon-based heat source 108 is located close enough to the tobacco material 110 so that the aerosol formed by heating the tobacco material 110 can be delivered to the user via the mouthpiece end 106. Thus, when the carbon-based heat source 108 heats the tobacco material 110, the aerosol is formed, released or generated in a physical form suitable for inhalation by the consumer. It should be noted that the above terms should be considered interchangeable, so that forms of the specified term, such as "release, release, releases or released", include forms such as "form or create, formation or creation, forms or creates and formed or created". In particular, the substance suitable for inhalation is released in the form of an aerosol.

As indicated above, in some embodiments, the smoking article 100 may comprise a tobacco material 110 located downstream of the carbon-based heat source 108 and optionally spatially separated from the mouth end 106 of the smoking article 100. In some embodiments, the tobacco material 110 may be in the form of particles, ground form, or in the form of sheets. In some embodiments, the tobacco material may also comprise one or both of an aerosol precursor composition and a flavoring agent. The tobacco materials used may vary. One type of tobacco may be used, or combinations or mixtures of different types of tobacco may be used. In addition, different types of tobacco or different mixtures of tobacco may be used in different locations within the smoking article.

For example, in some embodiments, the tobacco material used may include or be derived from tobaccos such as flue-cured tobacco, burley tobacco, oriental tobacco, Maryland tobacco, dark tobacco, dark fire-cured tobacco, and shag, as well as other rare or specialty tobaccos, or mixtures thereof. See also, for example, the types of tobaccos set forth in U.S. Patent No. 6,730,832 to Dominguez et al.; and No. 7,025,066 to Lawson et al.; and U.S. patent application Ser. No. 60/818,198, filed June 30, 2006, to Stebbins et al., each of which is incorporated herein by reference. Descriptions of various types of tobacco products, growing methods, harvesting methods, and aging methods are set forth in Tobacco Production, Chemistry and Technology, Davis et al. (eds.) (1999). Most preferably, the tobacco used has been suitably aged and cured. Particularly preferred methods and conditions for curing flue-cured tobacco are set forth in Nestor et al., Beitrage Tabakforsch. Int., 20 (2003) 467-475 and in U.S. Patent No. 6,895,974 to Peele, which are incorporated herein by reference. Representative techniques and conditions for air-curing tobacco are set forth in Roton et al., Beitrage Tabakforsch. Int., 21 (2005) 305-320 and Staaf et al., Beitrage Tabakforsch. Int., 21 (2005) 321–330, which are incorporated herein by reference.

The tobacco material that is included in the smoking article may be used in a variety of forms; and combinations of different forms of tobacco may be used, or different types of tobacco may be used in different places in the smoking article. For example, the tobacco may be used in the form of cut or shredded pieces of lamina or stem; in processed form (e.g., reconstituted tobacco leaf, such as pieces of reconstituted tobacco leaf shredded into cut filler; films containing tobacco components; extruded portions or pieces of tobacco; expanded tobacco lamina, such as cut filler that has been expanded in volume; pieces of processed tobacco stems comparable to cut filler in size and general appearance; granulated tobacco; foamed tobacco materials; compressed or pelleted tobacco, or the like); in the form of pieces of finely divided tobacco (e.g., tobacco dust, tobacco powder, agglomerated tobacco powders, or the like); or in the form of a tobacco extract. See, for example, U.S. Patent Application No. 11/194,215, filed August 1, 2005, to Cantrell et al. and U.S. Patent Application No. 11/377,630, filed March 16, 2006, to Crooks et al.; which are incorporated herein by reference.

The smoking article may use tobacco in the form of a lamina and/or a stem. Thus, the tobacco may be used in forms and in ways that are in many respects virtually identical to those traditionally used in the manufacture of tobacco products such as cigarettes. Traditionally, cut or shredded pieces of tobacco lamina and stem have been used as so-called "cut filler" to manufacture cigarettes. In addition, pieces of stems extracted with water may be used. In this way, the tobacco in this form gives the smoking article mass and volume. Methods and techniques for curing, destemming, curing, moistening, cutting, rearranging and processing tobacco used as cut filler will be apparent to those skilled in the art of tobacco product manufacturing.

The processed tobacco that may be included in the smoking article may vary. Examples of methods and techniques for producing reconstituted tobacco leaf, including molding and papermaking techniques, are set forth in U.S. Patents 4,674,519 to Keritsis et al.; 4,941,484 to Clapp et al.; 4,987,906 to Young et al.; 4,972,854 to Kiernan et al.; 5,099,864 to Young et al.; 5,143,097 to Sohn et al.; 5,159,942 to Brinkley et al.; 5,322,076 to Brinkley et al.; No. 5,339,838 to Young et al.; No. 5,377,698 to Litzinger et al.; No. 5,501,237 to Young; and No. 6,216,707 to Kumar, each of which is incorporated herein by reference. Examples of methods and techniques for providing extruded forms of processed tobacco are set forth in U.S. Pat. No. 4,821,749 to Toft et al.; No. 4,880,018 to Graves, Jr. et al.; No. 5,072,744 to Luke et al.; No. 4,874,000 to Tamol et al.; No. 5,551,450 to Hemsley; No. 5,649,552 to Cho et al.; No. 5,829,453 to White; No. 6,125,855 to Nevett et al.; and No. 6,182,670 to White, each of which is incorporated herein by reference. The extruded tobacco materials may be in the form of cylinders, strands, disks, or the like. Exemplary expanded tobacco (e.g., air-blown tobacco) may be provided using the types of techniques set forth in U.S. Pat. Nos. Re 32,013 to de la Burde et al.; No. 3,771,533 to Armstrong et al.; No. 4,577,646 to Ziehn; No. 4,962,773 to White; No. 5,095,922 to Johnson et al.; No. 5,143,096 to Steinberg; No. 5,172,707 to Zambelli; No. 5,249,588 to Brown et al.; No. 5,687,748 to Conrad; and No. 5,908,032 to Poindexter; and U.S. Patent Publication No. 2004/0182404 to Poindexter et al., each of which is incorporated herein by reference. One particularly preferred form of expanded tobacco is dry ice expanded tobacco (DIET). Exemplary forms of processed tobacco stems include cut twisted stems, cut twisted expanded stems, cut air stems, or shredded-steam expanded stems. Exemplary methods and techniques for producing processed tobacco stems are set forth in U.S. Patent Nos. 4,195,646 to Kite; 5,873,372 to Honeycutt et al., each of which is incorporated herein by reference. Methods and techniques for using tobacco dust are set forth in U.S. Patent Nos. 4,341,228 to Keritsis et al.; 4,611,608 to Vos et al.; 4,706,692 to Gellatly; and 5,724,998 to Gellatly et al., each of which is incorporated herein by reference. Still other types of processed tobacco are of the type set forth in U.S. Patent Publication No. 2006/0162733 to McGrath et al.

Tobacco may be used in a blended form. Typically, blends of different types and kinds of tobacco are provided as a blended cut filler. For example, some popular cigarette blends, commonly referred to as "American blends," include blends of cut or shredded pieces of flue-cured tobacco, Burley tobacco, and Oriental tobacco; and such blends in many cases also contain pieces of processed tobacco such as processed stems, bulked tobacco, and/or reconstituted tobacco. The exact amount of each type or kind of tobacco in the tobacco blend used to produce a particular smoking article may vary and is a matter of design choice, depending on factors such as the desired sensory characteristics (e.g., flavor and aroma). See, for example, the tobacco blend types described in Tobacco Encyclopedia, Voges (Ed.) pp. 44-45 (1984), Browne, The Design of Cigarettes, 3 ^rd Ed., p. 43 (1990), and Tobacco Production, Chemistry and Technology, Davis et al. (eds.) p. 346 (1999). See also the representative tobacco blend types set forth in U.S. Patents 4,836,224 to Lawson et al.; 4,924,888 to Perfetti et al.; 5,056,537 to Brown et al.; and 5,220,930 to Gentry; in U.S. Patent Application Publication No. 2004/0255965 to Perfetti et al.; and 2005/0066986 to Nestor et al.; in PCT Application Publication No. WO 02/37990 to Bereman; and Bombick et al., Fund. Appl. Toxicol, 39, pp. 11-17 (1997); each of which is incorporated herein by reference.

A particular processed tobacco may include ingredients other than tobacco. However, it is preferred that the processed tobacco consist predominantly of one or another type of tobacco, based on the dry weight of the processed tobacco. That is, the majority of the dry weight of the processed tobacco and the majority of the weight of the mixture comprising the processed tobacco (including the mixture of materials or materials having additives applied thereto or otherwise included therein) is provided by the particular type of tobacco. For example, these materials may be processed tobacco that includes minor amounts of non-tobacco fillers (e.g., calcium carbonate particles, spongy or absorbent materials, carbonaceous materials including carbon particles and graphite fibers, grains or wood pulp) and/or binders (e.g., guar gum, sodium alginate or ammonium alginate); and/or the mixture of these materials may include tobacco substitutes or extenders. Exemplary types of tobacco substitutes or extenders are set forth in U.S. Patent Application Ser. No. 11/489,334, filed July 19, 2006, to Fagg et al., which is incorporated herein by reference. The above materials and mixtures containing these materials often contain greater than about 70 percent tobacco, often greater than about 80 percent tobacco, and typically greater than about 90 percent tobacco, on a dry weight basis, based on the combined weight of tobacco, material without tobacco filler, and non-tobacco substitute or extender. However, this processed tobacco may also be made from substantially all tobacco and may not contain any non-tobacco fillers, substitutes, or extenders.

Tobacco may be treated with tobacco additives that are commonly used in the manufacture of tobacco products. These additives may include materials of the types used to enhance the flavor and aroma of tobacco in the manufacture of cigars, cigarettes, pipes, and the like. For example, these additives may include various cigarette wrappers and/or topcoat components. See, e.g., U.S. Patents 3,419,015 to Wochnowski; 4,054,145 to Berndt et al.; 4,887,619 to Burcham, Jr. et al.; 5,022,416 to Watson; 5,103,842 to Strang et al.; and 5,711,320 to Martin. Preferred casing materials include water, sugars and syrups (e.g., sucrose, glucose, and high fructose corn syrup), humectants (e.g., glycerin or propylene glycol), and flavoring agents (e.g., cocoa and licorice). These added components also include topcoat materials (e.g., flavoring materials such as menthol). See, e.g., U.S. Patent No. 4,449,541 to Mays et al. Additives may also be added to the tobacco using the types of equipment described in U.S. Patent No. 4,995,405 to Lettau or available as the Menthol Application System MAS from Kohl Maschinenbau GmbH. The selection of the particular shell and topcoat components will depend on such factors as the desired sensory characteristics, and the selection and use of these components will be readily apparent to those skilled in the art of cigarette design and manufacturing. See Gutcho, Tobacco Flavoring Substances and Methods, Noyes Data Corp. (1972), and Leffingwell et al., Tobacco Flavoring for Smoking Products (1972). The tobacco may also be treated with, for example, ammonia or ammonium hydroxide, or otherwise treated to include ammonia (e.g., by adding ammonia salts such as, for example, diammonium phosphate). Preferably, the amount of ammonia optionally included in the smoking tobacco is less than about 5 percent and typically from about 1 to about 3 percent, based on the dry weight of the tobacco.

Tobacco may be included in a smoking article in a form other than as cut filler. For example, tobacco leaf and/or reconstituted tobacco leaf may be used as a wrapper for a tobacco-containing component shaped like a cigar or as an inner wrapper for a double-wrapped cigarette rod. Alternatively, processed tobacco, such as certain types of reconstituted tobacco, may be used as longitudinally extending strands. See, for example, the type of configuration set forth in U.S. Patent No. 5,025,814 to Raker, which is incorporated herein by reference. Additionally, certain types of reconstituted tobacco sheets may be formed, rolled, or assembled into a desired configuration. Additionally, molded, compressed, or extruded portions or pieces of tobacco-containing materials that are formed into desired shapes (e.g., strands, tubes, cylinders, pellets, or the like) may be included in a smoking article. See, for example, U.S. Patent No. 4,836,225 to Sudoh, U.S. Patent No. 4,893,639 to White, U.S. Patent No. 4,972,855 to Kuriyama et al., and U.S. Patent No. 5,293,883 to Edwards, each of which is incorporated herein by reference. If desired, the finely ground tobacco or tobacco dust may be included in other types of processed tobacco, such as extrudate compositions, reconstituted tobacco sheets, or the like. Additionally, the finely ground tobacco or tobacco dust may be contained on substrates, such as membranes or screens. If desired, at least a portion of the tobacco may be thermally processed prior to use within the smoking article (e.g., in the form of high temperature cured, toasted, pre-pyrolyzed tobacco, condensed volatiles collected after heating the tobacco, condensed tobacco smoke components, or the like).

Various methods and techniques for incorporating tobacco into smoking articles, and in particular smoking articles that are designed to not intentionally burn substantially all of the tobacco in the smoking article, are set forth in U.S. Patent No. 4,947,874 to Brooks et al.; U.S. Patent Application Publication No. 2005/0016549 to Banerjee et al.; and U.S. Patent Application Ser. Nos. 11/194,215, filed August 1, 2005, to Cantrell et al., and 11/377,630, filed March 16, 2006, to Crooks et al., all of which are incorporated herein by reference. In addition, tobacco was included in cigarettes sold under the trade names "Premier" and "Eclipse" by R. J. Reynolds Tobacco Company. See, for example, the types of cigarettes described in Chemical and Biological Studies on New Cigarette Prototypes that Heat Instead of Burn Tobacco by R. J. Reynolds Tobacco Company (1988) and Inhalation Toxicology, 12:5, p. 1-58 (2000). Tobacco was also included in a smoking product sold by Philip Morris Inc. under the trade name "Accord."

As noted above, in some embodiments, the tobacco material 110 may also comprise an aerosol precursor composition. In some embodiments, the aerosol precursor composition may comprise glycerin or propylene glycol. Preferred aerosol-forming materials include polyhydric alcohols (e.g., glycerin, propylene glycol, and triethylene glycol) and/or water and any other materials that form a visible aerosol, as well as any combinations thereof. Representative types of aerosol-forming materials are listed in U.S. Patent No. 4,793,365 to Sensabaugh, Jr. and No. 5,101,839 by Jakob et al., in PCT Patent Application Publication No. WO 98/57556 by Biggs et al., and in Chemical and Biological Studies on New Cigarette Prototypes that Heat Instead of Burn Tobacco by R. J. Reynolds Tobacco Company (1988), the disclosures of which are incorporated herein by reference in their entireties.

Other representative types of aerosol precursor components and compositions are also known and are characterized in U.S. Patent Nos. 7,217,320 to Robinson et al., 8,881,737 to Collett et al., and 9,254,002 to Chong et al.; U.S. Patent Application Publication Nos. 2013/0008457 to Zheng et al.; 2015/0020823 to Lipowicz et al.; and 2015/0020830 to Koller; and WO 2014/182736 to Bowen et al., the disclosures of which are incorporated herein by reference in their entireties. Other aerosol precursors that may be used include the aerosol precursors that are included in the VUSE® products of R. J. Reynolds Vapor Company, the BLU™ products of Fontem Ventures B. V., the MISTIC MENTHOL product of Mistic Ecigs, the MARK TEN products of Nu Mark LLC, the JUUL product of Juul Labs, Inc., and the VYPE products of British American Tobacco. Also preferred are the so-called "smoke juices" for electronic cigarettes that are available from Johnson Creek Enterprises LLC. Other additional examples of aerosol precursor compositions are sold under the trademarks BLACK NOTE, COSMIC FOG, THE MILKMAN E-LIQUID, FIVE PAWNS, THE VAPOR CHEF, VAPE WILD, BOOSTED, THE STEAM FACTORY, MECH SAUCE, CASEY JONES MAINLINE RESERVE, MITTEN VAPORS, DR. CRIMMY'S V-LIQUID, SMILEY E LIQUID, BEANTOWN VAPOR, CUTTWOOD, CYCLOPS VAPOR, SICBOY, GOOD LIFE VAPOR, TELEOS, PINUP VAPORS, SPACE JAM, MT. BAKER VAPOR and JIMMY THE JUICE MAN. Embodiments of effervescent materials described, by way of example, in U.S. Patent Application Publication No. 2012/0055494 to Hunt et al., which is incorporated herein by reference in its entirety, may be used with the aerosol precursor composition. In addition, the use of effervescent materials is described, for example, in U.S. Patent Nos. 4,639,368 to Niazi et al., 5,178,878 to Wehling et al., 5,223,264 to Wehling et al., 6,974,590 to Pather et al., 7,381,667 to Bergquist et al., 8,424,541 to Crawford et al., 8,627,828 to Strickland et al., and 9,307,787 to Sun et al., as well as in U.S. Patent Application Publication No. 2010/0018539 to Brinkley et al. and in PCT application No. WO 97/06786 to Johnson et al., all of which are incorporated herein by reference in their entireties. Further description regarding embodiments of aerosol precursor compositions, including a description of tobacco or components derived from tobacco contained therein, is provided in U.S. Patent Application Publication Nos. 2018/0020722 and 2018/0020723, each to Davis et al., which are incorporated herein by reference in their entireties.

As noted above, the tobacco material 110 may also include a flavoring agent. As used herein, reference to a "flavoring agent" refers to compounds or components that can be aerosolized or delivered to a user and that convey a sensory experience of taste and/or aroma. Some examples of flavoring agents include, but are not limited to, vanillin, ethyl vanillin, cream, tea, coffee, fruit (e.g., apple, cherry, strawberry, peach, and citrus flavors including lime and lemon), maple, menthol, mint, peppermint, spearmint, wintergreen, nutmeg, clove, lavender, cardamom, ginger, honey, anise, sage, rosemary, hibiscus, rose hips, yerba mate, guayusa, honeybush, rooibos, yerba mate, bacopa monnieri, ginkgo biloba, withania somnifera, cinnamon, sandalwood, jasmine, cascarola, cocoa, licorice, and flavoring agents of the type and nature traditionally used to flavor cigarette, cigar, and pipe tobacco. In addition, syrups such as high fructose corn syrup may be used. Some examples of plant-derived compositions that may be useful are described in U.S. Patent No. 9,107,453 and U.S. Patent Application Publication No. 2012/0152265, both to Dube et al., the disclosures of which are incorporated herein by reference in their entireties. The selection of such additional components varies depending on such factors as the sensory characteristics desired in the smoking article, their affinity for the tobacco material, their solubility, and other physicochemical properties. The present disclosure encompasses any such additional components that are readily apparent to those skilled in the art of tobacco and tobacco-related or tobacco-derived products. See, for example, Gutcho, Tobacco Flavoring Substances and Methods, Noyes Data Corp. (1972), and Leffingwell et al., Tobacco Flavoring for Smoking Products (1972), the disclosures of which are incorporated herein by reference in their entirety. It should be noted that reference to a flavoring agent need not be limited to any one flavoring agent as described above, and may in fact be a combination of one or more flavoring agents.

As indicated above, in some embodiments, the smoking article 100 may comprise a thermal energy absorber 112 at least partially located between the tobacco material 110 and the carbon-based heat source 108. In various embodiments, the thermal energy absorber may be selected from the group consisting of metals and ceramics. In some embodiments, the thermal energy absorber may be an aluminum material (Al) or an aluminum oxide material (Al ₂ O ₃ ). In some embodiments, the thermal energy absorbers may comprise any metal, ceramic or other suitable material with a specific heat capacity of from about 0.1 kJ/(kg⋅K) to about 3 kJ/(kg⋅K), or preferably from about 0.5 kJ/(kg⋅K) to about 2 kJ/(kg⋅K), or more preferably from about 0.75 kJ/(kg⋅K) to about 1 kJ/(kg⋅K). The specific properties of materials suitable for use as thermal energy absorbers in the present disclosure may vary depending on the specific embodiments. Suitable materials for use as thermal energy absorbers in the present disclosure may include, but are not limited to, materials with properties such as high thermal stability, suitable specific heat capacity, or high thermal conductivity. In addition, suitable materials for use as thermal energy absorbers in the present disclosure may be non-toxic, non-hazardous materials with minimal adverse health effects.

In some embodiments, the thermal energy absorbers according to the present disclosure may be configured to increase the uniform distribution of heated air across the tobacco material. In some embodiments, the thermal energy absorber may be configured to reduce the maximum temperature of the smoking article by an amount from about 50°C to about 500°C. In some embodiments, the thermal energy absorbers may be configured to reduce the maximum temperature of the smoking article by an amount of at least about 50°C, or at least about 100°C, or at least about 150°C, or at least about 200°C, or at least about 250°C, or at least about 300°C, or at least about 350°C, or at least about 400°C, or at least about 450°C, or at least about 500°C. In some embodiments, the thermal energy absorber may be configured to provide an average maximum temperature in smoking articles below about 500°C, or below about 450°C, or below about 400°C, or below about 350°C, or below about 300°C, or below about 250°C, or below about 200°C, or below about 150°C.

In various embodiments, the thermal energy absorber may be configured to minimize the reduction in total particulate matter (TPM) released during smoking of the smoking article. Preferably, the thermal energy absorbers according to the present disclosure may be configured to provide a similar TPM release during smoking of a smoking article with thermal energy absorbers compared to a smoking article without thermal energy absorbers, thereby producing visible aerosols with similar visual characteristics of a typical smoking article with the additional benefits of thermal energy absorbers. In some embodiments, the thermal energy absorbers may be configured to maintain a useful pressure drop in the smoking article during smoking from about -20 mmHg to about 20 mmHg, or from about -10 mmHg to about 10 mmHg, or about 0 mmHg compared to a control smoking article without thermal energy absorbers. Preferably, the thermal energy absorbers according to the present disclosure may be configured to provide substantially the same pressure drop in a smoking article with thermal energy absorbers as in a smoking article without thermal energy absorbers, thereby maintaining the same draw resistance for the user with the additional benefits of thermal energy absorbers.

In one or more embodiments, the thermal energy absorber may be in the form of one or more circular disks. In some embodiments, the one or more circular disks may also comprise a porous or non-porous material. In this regard, FIG. 3 shows a thermal energy absorber 112 in the form of a circular disk that comprises a plurality of openings 130 extending therethrough in a longitudinal direction. In some embodiments, the circular disks may have a diameter of from about 5 mm to about 9 mm, or from about 6 mm to about 8 mm, or about 7 mm. In some embodiments, the circular disks may have a thickness of from about 0.1 mm to about 4 mm, or from about 1 mm to about 3 mm, or about 2 mm. Although in various embodiments, the thermal energy absorbers may have different geometries and design parameters, including, for example, a substantially spherical shape or a triangular shape, the thermal energy absorbers 112 shown in FIG. 3, generally have a cylindrical disk shape with a plurality of holes of substantially similar size and uniformly distributed thereon, although variable sizes and/or variable spacing are also encompassed. In various other embodiments, the plurality of holes 130 may be irregularly shaped, randomly distributed, patterned, or distributed in any other configuration that can provide air flow through the thermal energy absorber. In some embodiments, individual holes may have a diameter of from about 0.1 to about 1 mm or from about 0.2 mm to about 0.5 mm.

The heat absorber shown in FIG. 3 was manufactured using additive manufacturing technology to accurately manufacture aluminum oxide disks with a diameter of 6.58 mm and a thickness of 1.5 mm. In the embodiment shown, a plurality of holes 130 are uniformly distributed around the circular disk to uniformly distribute heated air to the downstream tobacco material. In various other embodiments, one or more circular disks may be sufficiently porous such that a plurality of holes I are not necessary in one or more circular disks. For example, in such embodiments, one or more circular disks may comprise a metallic or ceramic material that is sufficiently porous to provide a pressure drop in the smoking article that is lower than the maximum pressure drop limit in such smoking articles. The porosity may range from macroscale porosity to nanoscale porosity. In addition, such porous metallic or ceramic materials may be in the form of a foam material.

In some embodiments, the thermal energy absorber 112 may be made in the form of a plurality of particles. In various embodiments, the particles may be substantially spherical in shape or may have an irregular shape. In some embodiments, the shape of the particles may vary, for example, the particles may be substantially in the shape of a sphere, a cube, a cylinder, or any other suitable three-dimensional shape. In some embodiments, the thermal energy absorber may comprise from about 5 to about 500 particles, or from about 7 to about 300 particles, or from about 10 to about 100 particles, or from about 12 to about 30 particles, or preferably from about 15 to about 20 particles. In some embodiments, the particles may have a diameter of from about 0.1 mm to about 5 mm, or from about 0.5 mm to about 4 mm, or from about 1 mm to about 3 mm, or about 2 mm. In some embodiments, particularly such embodiments with a large number of common particles, the particles may have a diameter of less than about 0.1 mm, or less than about 0.05 mm, or less than about 0.01 mm, or less than about 0.005 mm. In some embodiments, the thermal energy absorber 112 in the form of a plurality of particles may be designed such that the number of particles in the plurality of particles gradually decreases in number the farther the particles are from the heat source 108. For example, in some embodiments, the density of the particles of the thermal energy absorber may be highest near the heat source and lowest at a distance from the heat source. Thus, in some embodiments, the density of the particles of the thermal energy absorber may be inversely proportional to the distance at which these particles are from the heat source. In some embodiments, this inverse relationship may further ensure uniform heat distribution across the tobacco material. In various other embodiments, the thermal energy absorber may have the shape of hollow spheres. In some embodiments, the hollow portion of the hollow spheres may be filled with paraffin, wax, or any other suitable phase change materials. For example, hollow spheres according to such embodiments may provide heat absorbers with reduced mass and variable thermal properties.

As noted in FIG. 4, in one particular embodiment, the smoking article 100 according to the present invention may comprise a plurality of thermal energy absorbers 112, which may have substantially the same shape or be present in substantially different shapes. For example, as shown in FIG. 4, the thermal energy absorber 112 may include a first thermal energy absorbing component 112a, which is in the form of one or more circular disks, and may include a second thermal energy absorbing component 112b, which is in the form of one or more particles (for example, substantially spherical particles). In such embodiments, the first component 112a may be located between the tobacco material 110 and the carbon-based heat source 108, and the second component 112b may be mixed within the tobacco material 110. In some embodiments, the second component 112b may be configured such that the number of particles in the plurality of particles gradually decreases in number the further the particles are from the carbon-based heat source 108.

In various other embodiments, the present invention provides a method for reducing excess heat in a smoking article, comprising: providing a smoking article that comprises a carbon-based heat source, a tobacco material, a thermal energy absorber, and an outer wrapper material surrounding at least a portion of the smoking article, wherein the smoking article is defined by an upstream lighting end and a downstream mouthpiece end; and positioning the thermal energy absorber at least partially between the tobacco material and the carbon-based heat source such that the maximum temperature of the smoking article is reduced by a value of from about 25°C to about 75°C and from about 475°C to about 525°C upon ignition of the carbon-based heat source. In some embodiments, thermal energy absorbers prepared according to the present method can be configured to reduce the maximum temperature of the smoking article by at least about 50°C, or at least about 100°C, or at least about 150°C, or at least about 200°C, or at least about 250°C, or at least about 300°C, or at least about 350°C, or at least about 400°C, or at least about 450°C, or at least about 500°C. In some embodiments, the thermal energy absorbers prepared according to the present method may be configured to provide an average maximum temperature in smoking articles below about 500°C, or below about 450°C, or below about 400°C, or below about 350°C, or below about 300°C, or below about 250°C, or below about 200°C, or below about 150°C. In some embodiments, the method according to the present disclosure may also include providing a thermal energy absorber that is configured to increase the uniform distribution of heated air throughout the smoking article. In some embodiments, the method according to the present disclosure may also include providing a filter material located near the downstream mouth end of the smoking article.

Many modifications and other embodiments of the invention will become apparent to those skilled in the art to which this disclosure pertains, having the benefit of the teachings presented in the foregoing descriptions and associated drawings. It is therefore to be understood that the invention should not be limited to the specific embodiments disclosed herein, and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are used in this application, they are used in a general and descriptive sense only and not for purposes of limitation.

Examples

To investigate the performance of the thermal energy absorbers described in this document, samples of two different types of heated but not burned cigarettes (hereinafter referred to as "HNB1" and "HNB2") were prepared and tested in accordance with the following methods.

The HNB1 samples were handcrafted with 13mm x 27mm rimmed pads that combined the tobacco ball portion and the tobacco rod portion. Heat absorbers were embedded between the tobacco ball portion and the carbon-based heater. These samples used a dual filter system with a length of 14mm for the CA filter and a length of 7mm for the HAT filter. A total of 31 samples were prepared using this method, which are listed as follows:

5 control samples HNB1

5 HNB1 samples with aluminum wheels

3 HNB1 samples with alumina ceramic discs

3 HNB1 samples with 10 aluminum spheres

3 HNB1 samples with 15 aluminum spheres

3 HNB1 samples with 20 aluminum spheres

3 HNB1 samples with 10 alumina ceramic spheres

3 HNB1 samples with 15 alumina ceramic spheres

3 HNB1 samples with 20 alumina ceramic spheres

The HNB2 samples were prepared using hand-made smoking articles comprising a 12mm carbon tip (protruding 8mm from the paper wrapper), 13mm of tobacco substrate material (cast sheet filled with glycerin) following the carbon tip (covered with aluminum foil), 37mm of tobacco rod (filled with glycerin if necessary), and a 14mm of cellulose acetate filter followed by a 7mm hollow acetate tube. The HNB2 samples were then modified by making a straight cut in the tobacco rod between the carbon-based heater and a portion of the tobacco substrate (approximately 4mm deep) at a distance of 12mm (the length of the heat source) from the ignition end of the tobacco rod using a utility knife. Thermal energy absorbers were then placed in the cut behind the heat source. The straight cut was then wrapped with 13 mm x 27 mm tipping paper and the paper was glued to the rods to block any air gaps. In total, 76 specimens were prepared according to this method, which are listed as follows:

10 HNB2 reference samples

3 HNB2 samples with aluminum wheels

3 HNB2 samples with aluminum oxide ceramic discs

3 HNB2 samples with 5 aluminum spheres

3 HNB2 samples with 8 aluminum spheres

3 HNB2 samples with 10 aluminum spheres

10 HNB2 samples with 15 aluminum spheres

10 HNB2 samples with 18 aluminum spheres

10 HNB2 samples with 20 aluminum spheres

3 HNB2 samples with 5 alumina ceramic spheres

3 HNB2 samples with 7 alumina ceramic spheres

3 HNB2 samples with 10 alumina ceramic spheres

3 control samples of HNB2 with menthol

3 HNB2 samples with 15 menthol aluminum spheres

3 HNB2 samples with 18 aluminum spheres with menthol

3 HNB2 samples with 20 aluminum spheres with menthol

Example 1

Average maximum temperature profiles of the best candidate samples HNB1 and HNB2 with thermal energy absorbers (FIG. 5)

Thermal analysis experiments were conducted on all HNB1 and HNB2 samples to provide temperature profiles along the cigarette rods. A hypodermic needle was used to drill 0.50 mm diameter holes in two locations along the cigarette rods, 15 mm and 24 mm from the ignition end. Type K thermocouples (Omega Engineering, Norwalk, CT) with a 0.26 mm probe diameter were then inserted into the holes and sealed with a small amount of tipping glue (Adhesive 20009766). The insertion depth of the thermocouples was approximately 3.5 mm, which placed the thermocouple tip approximately on the centerline of the cigarette rod. Samples HNB1 and HNB2 were held in place with a custom-made labyrinth holder of conventional design. The act of “smoking” was performed using a custom smoking machine with a Schneider Electric Motion USA MDrivePlus 17 stepper motor. The stepper motor was programmed according to the specific puffing pattern described later in this document. The use of the stepper motor allowed for digital control of the piston movements. Finally, data collection was performed using an IntelliLogger (Logic Beach, La Mesa, California) and HyperWare II software (Logic Beach, La Mesa, California) was used to transfer the data to a computer for further analysis.

The test was conducted on samples HNB1 and HNB2, which contained circular aluminum disks; circular aluminum oxide ceramic disks; 5, 8, 10, 15, 18, and 20 aluminum spheres; and 5, 7, 10, 15, 18, and 20 aluminum oxide ceramic spheres. All products were smoked using a custom-made smoking machine for 19 puffs using a puff volume of 55 ml with a puff duration of two seconds. The first three puffs were considered ignition puffs and were essentially performed one after the other. The interval between puffs 1 and 2 and puffs 2 and 3 was approximately three seconds. The heat source was preheated for approximately one second using an electric lighter (Borgwaldt Electric Lighter R29) prior to puff 1, and light contact was maintained between the top of the lighter and the heat source until the end of puff 2. Puff 3 was taken with the lighter removed from the heat source. After puff 3, the intervals between the start of subsequent puffs were maintained at 30 seconds. The temperature of the tobacco core (centerline of the rod) at 15 mm and 24 mm lengths was measured with thermocouples, and a temperature profile was created from this data using the IntelliLogger.

A peak temperature value within each puff was identified, which was referred to as the “peak temperature” of the puff. Samples that exhibited a peak temperature (collected over 15 mm) lower than the control HNB2 samples from 100°C to 300°C were selected as high-performance “best” candidates. Based on the testing results, HNB2 samples with 15, 18, and 20 aluminum spheres were selected as the best candidates. As can be seen from FIG. 5, average peak temperature profiles were presented based on testing of the control HNB2 sticks without aluminum spheres and the HNB2 sticks containing 15, 18, and 20 aluminum spheres. The HNB2 stick sample containing 18 aluminum spheres produced the greatest decrease in peak temperature (over 300°C) during smoking; however, all three stick samples produced a decrease in peak temperature compared to the control sample.

Example 2

Average pressure drop data for the best candidate samples HNB1 and HNB2 with thermal energy absorbers (FIG. 6)

In order to accurately compare two cigarette rods containing different types or constituents of tobacco, it is important to evaluate and compare the average pressure drops along the rods. Air pressure drop is directly proportional to the resistance to the air drawing force required to draw the aerosols through the rod and filter. It is known that pressure drop and draw resistance of a cigarette have a direct impact on the smoking characteristics of the cigarette. A pressure drop unit built into the Quality Management Module (QTM) setup was used to measure the air pressure drop across the samples. The QTM provided the percentage of dilution in the filter and the pressure drop measured and presented separately with the dilution holes open and the dilution holes closed. The dilution holes in the QTM test are prepared with a laser orifice making component that cuts a hole in the side of the tobacco rod downstream of the carbon-based tip. For closed-hole testing of the samples, the dilution holes are closed while the QTM performs the test such that air only enters the samples from the carbon-based tip. For open-hole testing of specimens, the dilution ports are left open while the QTM performs the test so that air is drawn into the specimen through both the carbon tip and the dilution ports. The QTM has an industry standard protocol that provides an air draw of 17.5 ^cc per second. The QTM also provided other physical properties of the specimens, including rod weight and rod circumference.

In particular, in FIG. 6, a pressure drop analysis was performed on candidate samples that were believed to have the best performance in the temperature analysis described in Example 1. The test samples included HNB2 samples with 15, 18, and 20 aluminum spheres and a control HNB2 sample for comparison. As shown in FIG. 6, pressure drop data were presented for both open-hole and closed-hole tests based on testing of control HNB2 rods and HNB2 rods containing 15 aluminum spheres, HNB2 rods containing 18 aluminum spheres, and HNB2 rods containing 20 aluminum spheres. As noted in FIG. 6, the average pressure drop on the HNB2 rods with aluminum spheres ranged from -5 mmHg to 10 mmHg compared to the control HNB2 rod samples that did not contain aluminum spheres. It was noted that the pressure drops in the HNB2 control sample were essentially similar to the best HNB2 candidate samples. This confirms that the addition of thermal energy absorbers did not significantly affect the pressure drops in the HNB2 samples and resulted in changes in the product characteristics related to user draw resistance due to the change in pressure drop.

Example 3

Total amount of particulate matter released by the best candidates HNB1 and HNB2 with thermal energy absorbers (FIG. 7)

The total particulate matter (TPM) released when a smoking product is smoked can affect the visibility of the aerosols generated from it.

For example, reducing the TPM released during smoking of a smoking product may reduce the visibility of the aerosol generated from that smoking product.

The TPM analysis experiments were conducted using the custom-built smoking machine described in Example 1. The smoking machine was programmed to provide a 50/30/3 puff pattern (puff volume 50 ml/puff frequency 30 seconds/puff duration 3 seconds) and was used to quantify total particulate matter (TPM) during smoking of the test samples. A 44 mm diameter Cambridge filter pad was placed in the pad holder and weighed to determine the initial mass. The holder was then attached to the smoking machine and the sample was inserted. Twelve puffs were performed on each sample. The filter pad was then removed from the holder and the final mass was measured using a high-precision scale. The difference between the mass of the filter pads before and after each test yielded the total TPM value, which was averaged over the 12 puffs to calculate the mass on a mg/puff basis for each test sample.

As shown in FIG. 7, the test samples included HNB2 samples with 15, 18, and 20 aluminum spheres and a control HNB2 sample for comparison. As shown in FIG. 7, the control HNB2 sample, HNB2 sample with 15 aluminum spheres, HNB2 sample with 18 aluminum spheres, and HNB2 sample with 20 aluminum spheres generated TPM values of 1.58, 1.17, 1.00, and 1.00 mg/puff, respectively. The results, as shown in FIG. 7, suggest that the TPM generated in the control HNB2 samples is only slightly higher than the TPM generated from the HNB2 samples with thermal energy absorbers. Additionally, it was noted that the observed TPM values are inversely proportional to the number of aluminum spheres loaded into the HNB2 rods. Thus, the amount of visible aerosols generated in these samples is least affected by the smaller number of aluminum spheres, and also provides a reduction in the burning of tobacco rod components. This test also confirmed that the HNB2 sample with 15 aluminum spheres provides the best combination of both the minimum reduction in TPM values and the maximum reduction in the burning of tobacco rod components.

Claims (23)

1. A smoking article comprising an outer wrapper surrounding at least a portion of the smoking article, tobacco material, a filter located downstream of the tobacco material and near the mouth end of the smoking article, and an energy absorber located such that at least a portion of the energy absorber is mixed with the tobacco material, or such that the energy absorber is completely mixed with the tobacco material, wherein the energy absorber is a thermal energy absorber designed to increase the uniform distribution of heated air over the tobacco material. 2. A smoking article according to claim 1, wherein the tobacco material also includes one or more of the following: a tobacco extract, an aerosol precursor composition, and a flavoring agent. 3. A smoking article according to claim 1, wherein the tobacco material is in crushed form and/or in the form of particles. 4. A smoking article according to claim 1, wherein the energy absorber comprises a metallic material. 5. A smoking article according to claim 1, wherein the energy absorber comprises a ceramic material. 6. A smoking article according to claim 1, wherein the energy absorber is designed to distribute heat across the tobacco material. 7. A smoking article according to claim 1, wherein the energy absorber has a thickness of 0.1 mm. 8. A smoking article according to claim 1, wherein the filter comprises a plurality of separate parts. 9. A smoking article according to claim 8, wherein at least one of the plurality of individual parts is hollow. 10. A smoking article according to claim 1, wherein the smoking article is limited by an upstream lighting end and a downstream mouthpiece end. 11. A smoking article according to claim 10, wherein the smoking article also comprises a carbon-based heat source located near the ignition end. 12. A smoking article according to claim 11, wherein the carbon-based heat source has a plurality of air inlet openings passing through it in a longitudinal direction. 13. A smoking article according to item 1, wherein the thermal energy absorber is made in the form of one or more round disks. 14. A smoking article according to item 13, wherein one or more round discs have an individual diameter of 5 mm to 9 mm and a thickness of 0.1 mm to 4 mm. 15. A smoking article according to claim 13, wherein one or more circular discs contain a plurality of holes. 16. A smoking article according to claim 15, wherein the plurality of holes are irregularly shaped, randomly distributed, or distributed according to a pattern. 17. A smoking article according to claim 1, wherein the thermal energy absorber is made in the form of a plurality of particles. 18. A smoking article according to claim 17, wherein the particles have a spherical shape. 19. A smoking article according to claim 17, wherein the thermal energy absorber contains from 3 to 500 particles. 20. A smoking article according to claim 18, wherein the particles have a diameter of from 0.005 mm to 5 mm. 21. A smoking article according to claim 1, wherein the thermal energy absorber comprises a material with a specific heat capacity of from 0.1 kJ/(kg⋅K) to 3 kJ/(kg⋅K). 22. A smoking article according to claim 1, wherein the thermal energy absorber is designed with the possibility of reducing the maximum temperature of the smoking article by an amount from 50°C to 500°C. 23. A method for reducing excess heat in a smoking article, comprising providing a smoking article that comprises a carbon-based heat source, a tobacco material, a thermal energy absorber and an outer wrapper surrounding at least a portion of the smoking article, wherein the smoking article is formed by an upstream ignition end and a downstream mouthpiece end, and arranging the thermal energy absorber at least partially between the tobacco material and the carbon-based heat source such that the maximum temperature of the smoking article is reduced by an amount from 50°C to 500°C upon ignition of the carbon-based heat source, wherein the thermal energy absorber is designed to increase the uniform distribution of heated air over the tobacco material.