DK174292B1 - Low mutagenic smoking article, e.g. cigarette - has carbonaceous fuel element in heat exchange relationship with aerosol source - Google Patents

Abstract

The cigarette has a carbonaceous fuel element. A separate aerosol generator has a substrate bearing an aerosol forming material. The fuel element and substrate are arranged in a conductive relationship, so that the heat-stable substrate receives conductive heat transfer throughout the burning time of the fuel element. The fuel element is less than 30mm in length, with a density of at least 5 g/cc. An insulation material can surround part of the fuel element. The insulation is resilient and at least 15 mm thick. The cigarette also has a mouthpiece.

Description

DK 174292 B1

The present invention relates to a smoking product of the kind set forth in claim 1. The smoking product produces an aerosol similar to tobacco smoke and containing no more than a minimal amount of incomplete combustion or pyrolysis products.

Over the years and especially in the last 20 to 30 years, many smoking products have been proposed, but 5 none of these products have ever achieved any market success.

U.S. Patent Specification. No. 4,340,072 proposes smoking products with a fuel rod having a mid-space open orifice for atmospheric air and a chamber located at the orifice containing an inhalation material. The fuel rod is preferably a molded or extruded item of reconstituted tobacco and / or tobacco substitute, although the paper also suggests the use of tobacco, a mixture of tobacco substitute material and carbon, or a mixture of sodium carboxymethyl cellulose and carbon. It is suggested that the inhalation material is a nicotine-delivering material or granules or microcapsules of a flavor or flavoring agent in triacetin or benzyl benzoate. Upon burning, atmospheric air flows into the flow duct where it is mixed with combustion gases from the burning fuel. The flow of these gases is said to break the grains or microcapsules to release the volatile material. The length of the smoking product proposed in this patent is said to be 70 mm and the length of the fuel elements in the illustrated embodiments is thus of an order of 50 mm.

SE Patent Specification. 220,072 proposes smoking products having an outer fuel cylinder having good 20 odor characteristics, preferably finely cut tobacco or reconstituted tobacco, surrounding a metal tube containing tobacco, reconstituted tobacco or another substance with nicotine and water vapor. The items also have an mouth filter. By heating the burning portion of the smoking fuel, the adjacent nicotine-containing material in the metal tube and causing the release of nicotine vapors and potentially aerosol-forming material, including water vapor. A major shortcoming of this product is that as the tobacco fuel is used up, the metal tube eventually protrudes. Other clear deficiencies include the presence of significant tobacco pyrolysis products, substantial tobacco side stream smoke and ash and the possibility of pyrolysis of the nicotine-containing material in the metal tube.

Thus, from these writings, an oblong smoking product of the cigarette type using a combustible fuel element is known in connection with a physically separate aerosol forming member which is in heat exchanger connection with the fuel element. Upon ignition, the fuel element generates heat which is used to evaporate the aerosol forming mass or masses in the aerosol forming member. These volatile materials are then sucked towards the mouth end, especially during the smoking, and into the user's mouth in the same way as the smoke of a known cigarette. In the prior art smokers, which attempt to form an aerosol similar to tobacco-10 smoke, little or no air was produced at all:> sun produced during smoking. This is especially true during the first part of smoking, ie. , during the first sucks.

Therefore, despite decades of interest and efforts, there are still no smoking products on the market that provide the benefits and benefits of regular cigarette smoking without providing substantial quantities of incomplete combustion and pyrolysis products.

The object of the present invention is to apply; see a smoking product capable of producing significant amounts of aerosol both from the first and throughout the useful life of the product without any significant heat degradation of the aerosol generator and without the presence of significant pyrolysis or incomplete combustion products, and preferably without significant amounts of sidestream smoke. In particular, the object of the present invention is to reduce radial heat loss from the fuel element. The smoking product of the present invention can give the user the sensations and benefits of cigarette smoking without the combustion of tobacco.

This object is met by the fact that the smoking product according to the invention mentioned above is peculiar to that of the characterizing part of claim 1. The insulating portion surrounding the fuel element reduces the radial heat loss from the fuel element and helps to retain and direct the heat from the fuel element towards the aerosol forming member. This results in a more efficient use of heat from the burning fuel element, so that improved amounts of an aerosol resembling tobacco smoke can be produced, and further enables an efficient construction and / or composition of the fuel element.

Advantageously, the smoking product has the size and length of a conventional tobacco burning cigarette, and since the insulating portion is elastic, it helps to simulate that the smoking product of the invention has the same grip or feel in the same manner as a known cigarette.

In the characterizing part of claim 2, it is stated that the insulating part surrounds at least one part of the aerosol forming member. This helps keep the heat within the aerosol-forming organ so that the aerosol-forming organ does not become cold during the relatively long wetting period between the times when the cigarette is sucked.

The characterizing part of claim 3 indicates that the fuel element and the aerosol forming member are in conductive heat exchange with each other. This conductive heat exchange improves the supply of heat to the aerosol forming body. The insulating part assists in controlling the heat conduction exchange from the fuel to the aerosol forming member.

The characterizing part of claim 4 indicates that the fuel element is shorter than 30 mm. The use of shortened fuel elements allows for increased supply of useful heat from the fuel element to the aerosol forming member. Since the fuel element is surrounded by the insulating part, a small fuel element can be used more efficiently.

In the characterizing part of claim 5, the insulating part comprises inorganic fibers.

These preferred insulating parts can be easily provided in the resilient form and allow oxygen to be readily supplied to the burning fuel element.

The characterizing part of claim 6 indicates that a cigarette paper surrounds the insulating part.

The cigarette paper helps to simulate the look and feel of a known tobacco burning cigarette.

DK 174292 B1 4

These and other advantages are obtained by providing an elongated smoking article of the cigarette type using a combustible fuel element, preferably of a carbonaceous material, in conjunction with a physically separate aerosol forming member which is in conductive heat exchanger communication with the fuel element. Upon ignition, the fuel element generates heat which is used to evaporate the aerosol forming mass or masses in the aerosol forming member. These volatile materials are then sucked towards the mouth end, especially during the smoking 10 and into the user's mouth in the same manner as a known c in the smoke of the yard.

Preferably, the fuel element is less than ca. 30 mm long, especially less than 15 mm long, has a density of at least 0.5 g / cc and has one or more longitudinal channels. The aerosol forming member advantageously comprises a heat stable substrate comprising one or more aerosol forming substances. Preferably, the heat exchange between the fuel and the aerosol generator is obtained by providing a heat conducting member, such as a metal foil, which effectively conducts and transfers heat from the burning fuel element to the aerosol forming member. This heat conducting portion preferably touches the fuel element and the aerosol forming member along at least one portion of their peripheral surfaces. In addition, at least one portion of the fuel element is provided with a peripheral insulating member, such as a sheath of 20 insulating fibers, which sheath is elastic and at least 0.5 mm thick, which reduces radiant heat loss and helps maintain and direct the heat from the fuel element towards the aerosol forming organ. The insulating portion is preferably wound over at least one portion of the fuel element and preferably over at least one portion of the aerosol forming member.

Since the fuel element is relatively short, the hot, burning fire cone is always close to the aerosol-forming member, giving as great a heat transfer as possible and resulting in as great aerosol production as possible, especially in embodiments equipped with a heat-conducting part. . The preferred use of a relatively short substrate or small mass carrier as an aerosol forming member located close to the short fuel element also increases the aerosol production by minimizing the heat protection effect of the substrate. Since the aerosol-forming substance is physically separated from the fuel element, it is subjected to substantially lower temperatures than those found in the burning fire cone, thereby reducing the possibility of the aerosol-forming heat decomposition to a minimum. Furthermore, the particularly preferred use of a carbonaceous fuel element which is substantially free of volatile organic material eliminates the presence of significant pyrolysis or incomplete combustion products and eliminates the formation of substantial sidestream smoke.

The smoke product of the invention is usually provided with a mouthpiece comprising means such as an elongate channel for delivering the volatile material formed by the aerosol forming member to the user. Advantageously, the product has the same overall dimensions as a known cigarette and as a result the mouthpiece and the aerosol delivery means generally extend over more than half the length of the product. Alternatively, the fuel element and the aerosol forming member may be manufactured without a built-in nozzle or aerosol delivery member for use with a separate single-use or recycling nozzle.

The smoking product of the present invention may also include a charge or tobacco plug which can be used to give the aerosol a tobacco flavor. The tobacco is preferably placed at the mouth of the aerosol forming member and can be mixed with the carrier for the aerosol forming substance. Other flavors can also be incorporated into the product to add flavor to the aerosol supplied to the user.

Preferred embodiments of the invention can provide at least 0.6 mg of aerosol, measured as wet total particulate matter in the first 3 sugars, when smoked under FTC smoking conditions.

25 (FTC smoking conditions consist of two sec suction (35 ml total volume) separated by 58 sec ulm). More preferred embodiments of the subject matter of the invention can deliver 1.5 mg or more aerosol in the first 3 sucks. Particularly preferred are embodiments of the invention capable of delivering 3 mg or more aerosol in the first 3 sugars when smoking under FTC smoking conditions. Preferred embodiments of the subject matter of the invention furthermore provide an average of at least approx. 0.8 mg of wet total particulate matter per soak for at least approx. 6 suction, preferably at least approx. 10 sucks under FTC smoking conditions.

The smoking product of the present invention may also provide an aerosol which is chemically simple, consisting essentially of carbon oxides, atmospheric air, water and the aerosol carrying the desired flavors or other desired volatile materials and trace amounts of other materials. Preferably, the aerosol has no significant mutagenic activity according to the Ames sample described below. In addition, the smoking product may in fact be ash-free so that the user does not have to remove any ash during use.

As used herein and only for the purposes of the present application, "aerosol" is defined to include vapors, gases, particles and the like, both visible and invisible, and in particular those components which the user perceives to be "smoke-like" and produced by the heat effect of the burning fuel element on substances contained in the aerosol forming member, or elsewhere in the article. As defined, the term "aerosol" also includes volatile flavoring and / or pharmacologically or physiologically active substances, whether or not they produce a visible aerosol.

As used herein, the words "conductive heat exchanger ratio" are defined as a physical arrangement of the aerosol-forming member and the fuel element, whereby heat is transferred by 20 conduction from the burning fuel element to the aerosol-forming member substantially throughout the combustion period of the fuel element. Conductive heat exchange can be achieved by placing the aerosol forming member in contact with the fuel element and close to the burning element of the fuel element, and / or by using a conductive member to carry heat from the burning fuel to the aerosol forming member. Preferably, both methods are used to provide heat conduction.

As used herein, the term "carbonaceous" means primarily comprising carbon.

7 DK 174292 B1

As used herein, the term "insulating organ" refers to all materials which primarily act as insulators. These materials preferably do not burn during use, but they may include slow-burning carbon and similar materials as well as materials that melt during use, such as low-temperature glass fibers. The insulators have a thermal conductivity measured in g-cal / (sec) (cm 2) (° C / cm) of less than approx. 0.05, preferably less than ca. 0.02, and in a particularly preferred embodiment less than ca. 0005. See. Hackh's Chemical Dictionary, 34 (4th ed., 1969) and Lange's Handbook of Chemistry, 10, 272-274 (ll. Ed., 1973).

The smoking articles according to the invention are described in more detail below with reference to the drawing, in which fig. 1 and 2 are longitudinal sections through two different smoking products, and FIG. 3 and 4 are longitudinal sections through two different embodiments of a smoking product according to the invention.

The FIG. 1, a smoking material comprises a fibrous carbon fuel element 10, such as carbonized cotton or silk. The fuel element has a single axial hole 16. The substrate 38 of the aerosol forming member is a granular, thermally stable carbon. A tobacco pulp 28 is located immediately behind the substrate. This article is provided with a cellulose acetate tube 40 which includes an annular section 42 of cellulose acetate tow which surrounds a possible plastic tube 44, e.g. of polypropylene. At the mouth 15 of this element there is a low efficiency cellulose acetate filter plug 45. The product is wrapped throughout its length with cigarette type paper 46. A cork or white-colored coating 48 may be applied to the mouth end to simulate a mouthpiece. A film strip 50 is located on the inside of the paper towards the fuel end of the article. This strip preferably extends from the rear of the fuel element to the mouth of the tobacco hinge 28. It may be formed integrally with the paper or 25 may be a separate piece applied before the paper cover.

DK 174292 B1 8

The FIG. 2 is similar to that of FIG. 1. In this embodiment, the aerosol forming member 12 is formed of an aluminum macrocapsule 52 filled with a comet substrate 54 and tobacco 56. The macrocapsule 52 is shrunk at its ends 58, 60 to enclose the material and prevent the aerosol generator from moving. The shrunk end 58 at the fuel end preferably bears against the rear end of the fuel element to provide heat transfer by conduit. A void 62 formed by the end 58 also helps prevent the aerosol generator from moving towards the fuel. There are longitudinal channels 59 and 61 to allow for the passage of atmospheric air and the aerosol-forming substance. Macro capsule 52 and fuel element 10 may be joined by known cigarette paper 47, as illustrated in the drawing, by perforated ceramic paper, or by a foil strip. If cigarette paper is used, the back of the fuel should be printed or treated with sodium silicate or other known substances that cause the paper to expire. The entire length of the item is wrapped with known cigarette paper 46.

The 3 and 4 embodiments of the invention comprise a non-burning insulating jacket 86 around the fuel element 10 to isolate and concentrate the heat in the fuel element. These embodiments also help to limit any burning-inducing potential of the burning fire cone.

In the embodiment shown in FIG. 3, both the fuel element 10 and the substrate 30 are located within an annular sheath or such tube 86 of insulating fibers, such as ceramic (e.g. glass) fibers. Non-combustible carbon or graphite fibers can be used instead of ceramic fibers. The fuel element 10 is preferably an extruded carbon plug with a hole 10.1. The illustrated embodiment extends the ignition end 11 slightly beyond the edge of the sheath 86 to facilitate ignition. The substrate 30 is a solid porous carbon material, although other substrate types can be used. The substrate and the rear of the fuel element are surrounded by an aluminum foil piece 87. As illustrated, this casing-carrying fuel / substrate unit is connected to an mouth end piece, such as the elongated cellulose acetate tube 40, shown in the drawing, with a cover of known cigarette paper 46. The cover 86 extends to the mouth of the substrate 30 and can replace the cellulose acetate rod 42.

9 DK 174292 B1 In the embodiment of FIG. 4, an aluminum macro capsule 82 of the embodiment of FIG. 2 to contain a cometic substrate 54 and tobacco 56. The macrocapsule is preferably located completely within the insulating sheath 86. Furthermore, the ignition end 11 of the fuel element 10 does not extend beyond the front of the sheath 86. It is preferred that the macro capsule and the rear portion of the fuel element are surrounded by an aluminum foil piece in a similar manner as shown in FIG. Third

Alternatively, the aluminum foil 52 surrounding the substrate is only shrunk at the mouth end. In such an embodiment, the rear end of the fuel element can be inserted at one end of the foil and a polypropylene tube can be passed over or placed in contact with the mouth of the foil. The entire 10 unit is wrapped with fiberglass to a diameter as for a known cigarette.

Upon ignition of one of said embodiments, the fuel element burns and produces the heat used to vaporize the aerosol-forming substance (s) present in the aerosol-forming member. These volatile materials are then sucked towards the mouth end, especially during suction and into the user's mouth in the same way as smoking a known cigarette.

Since the fuel element is preferably relatively short, the hot-burning fire cone is always close to the aerosoid-forming body, whereby the heat transfer to the aerosol-forming member and the resulting aerosol production becomes as large as possible, especially when the heat-conducting part is used. In addition, the insulating portion tends to limit, control, and concentrate the heat toward the center core of the article, thereby increasing the heat transfer to the aerosoid forming substance.

Since the aerosoid-forming substance is physically separate from the fuel element, it is subjected to substantially lower temperatures than those found in the burning fire cone. This minimizes the possibility of heat decomposition of the aerosol generator. This also results in aerosol production during suction, but little or no aerosol production during wetting. Furthermore, the use of the preferred carbonaceous fuel elements and a physically separate aerosol forming member eliminates the presence of essential pyrolysis or incomplete combustion products and avoids the formation of significant sidestream smoke.

Due to the small size and combustion characteristics of the preferred carbon-containing fuel element utilized in the present invention, the fuel element generally begins to burn over substantially its entire exposed length in a matter of a few sucks. Thus, the fuel element portion adjacent to the aerosol forming member rapidly becomes hot, which substantially increases the heat transfer to the aerosol forming member, especially during the first and middle suction. Since the preferred fuel element 10 is short, there is never a long piece of non-combustible fuel to act as a heat-spray, as was common in previous thermal aerosol articles. The heat transfer, and therefore the aerosol delivery, is also increased by the use of holes through the fuel which conducts hot air to the aerosol forming member, especially during suction.

In the preferred embodiments of the present invention, the short carbon-containing fuel element, the heat-conducting member, the insulating member, and ducts in the fuel interact with the aerosol-forming member to provide a system capable of producing substantial amounts of aeroso practically. on every suction. The location of the fire cone close to the aerosol forming means, after some suction, together with the insulating means, results in a large heat transfer both during suction and during relatively long 20 ulm periods between suction.

Without wishing to be bound by theory, it is presumed that the aerosol forming member is maintained at a relatively high temperature between the suction and that the additional heat supplied under the suction significantly increased by the hole or holes in the fuel element is preferably utilized to evaporate it. aerosol forming substance. This increased heat transfer 25 utilizes the available fuel energy more efficiently, reducing the amount of fuel needed and contributing to delivering early aerosol. The heat transfer used in the present invention by conduction is supposed to reduce the combustion temperature of the carbon fuel, which, it is further supposed, reduces the CO / CO 2 ratio of the combustion products produced by the fuel. See. eg. G. Hagg, General Inorganic Chemistry, page 592 (John Wiley & Sons, 1969).

Furthermore, by the appropriate choice of the fuel element, the insulating jacket, the paper cover and the heat conducting means, it is possible to control the burning characteristics of the fuel source.

This allows to control the heat transfer to the aerosol-forming organ, which in turn changes the number of suction and / or the amount of aerosol delivered to the user.

In general, the combustible fuel elements which can be used in the practice of the present invention are less than 30 mm long. Preferably, they are approx. 20 mm long or 10 smaller, preferably approx. 15 mm long or less. Advantageously, the diameter of the fuel element is between approx. 3 to 8 mm, preferably between ca. 4 to 5 mm. The density of the fuel elements used herein has ranged from approx. 0.5 g / cc to approx. 1.5 g / cc. It is preferred that the density is greater than 0.7 g / cc and preferably is greater than 0.8 g / cc. It is preferred that the fuel has one or more longitudinal holes such as the holes 16 in FIG. 1 to 15 4. These holes cause porosity and increase early heat transfer to the substrate by increasing the amount of hot gases reaching the substrate.

The fuel elements used herein are primarily formed of a carbonaceous material. Carbon-containing fuel elements preferably have a length of from approx. 5 to 15 mm and in particular a length from 8 to 12 mm. Carbon-containing fuel elements with these characteristics are sufficient to provide fuel for at least 7 to 10 puffs, the normal number of puffs commonly obtained by smoking a known cigarette under FTC conditions.

It is preferred that the carbon content of such a fuel element is at least 60 to 70% by weight and preferably at least 80% by weight. Excellent results have been obtained with fuel elements with a carbon content greater than approx. 8 5% by weight. High carbon fuels 25 are preferred as they produce minimal pyrolysis and incomplete combustion products, little or no visible sidestream smoke, and minimal ash and have a high heat capacity.

DK 174292 B1 12

Fuel elements with lower carbon content, e.g. However, 50-65% by weight is also within the scope of the present invention, especially when a non-combustible inactive filter is used.

Although not preferred, other fuel materials, such as tobacco, tobacco substitutes and the like, may also be used, provided that they generate and conduct sufficient heat to the aerosol forming body to produce the desired aerosol level from the aerosol forming material, cf. above. . The density of the fuel used should be above 0.5 g / cc, preferably above ca. 0.7 g / cc, which is greater than the densities normally used in known smoking products. Where such other materials are used, it is highly preferred to include carbon in the fuel, preferably in amounts of at least about 10%. 20-40% by weight and even more preferably at least 50% by weight and more preferably at least about 65-70% by weight, the remainder consisting of the other fuel components comprising any binder, combustibility, modifiers, moisture, etc.

The carbonaceous materials used in or as the preferred fuel can be derived from virtually any of numerous carbon sources known to those skilled in the art. It is preferred that the carbonaceous material be obtained by pyrolysis or carbonization of cellulosic materials such as wood, cotton, silk, tobacco, coconut, paper and the like, although carbonaceous materials from other sources may also be used.

In most cases, the carbonaceous fuel element should be able to ignite by means of a known cigarette lighter without the use of an oxidizing agent. Such combustion characteristics can generally be obtained from cellulosic materials which have been pyrolysized at temperatures between about 400 ° C to approx. 1000 ° C, preferably between ca. 500 ° C to approx. 950 ° C in an inert atmosphere or under vacuum. The pyrolysis time is not assumed to be critical as long as the temperature at the center of the pyrolyzed mass has reached the above-mentioned temperature range for at least a few minutes. However, a slow pyrolysis using gradually increasing temperatures over several hours is believed to produce a more uniform material with a higher carbon yield.

13 DK 174292 B1

Although in most cases undesirable, carbonaceous fuel elements requiring the addition of an oxidizing agent to be ignited by a cigarette lighter are within the scope of the present invention, as are carbonaceous materials requiring the use of soft or odor retardant. agents or other forms of combustion altering agents. Such combustion modifying agents are described in many patents and writings and are known to those skilled in the art.

The most preferred carbonaceous fuel elements used in the practice of the invention are substantially free of volatile organic matter. By this it is meant that the fuel element is not intentionally impregnated or mixed with substantial amounts of volatile organic materials, such as volatile aerosol-forming or flavoring substances, which could be degraded in the burning fuel. However, small amounts of water naturally adsorbed by the fuel may be present. Similarly, small amounts of aerosol-forming substance can migrate from the aerosol-forming organ and thus may also be present in the fuel element.

A preferred carbonaceous fuel element is a pressed or extruded carbon mass made of coal and a binder by known molding or extrusion methods. A preferred activated carbon for such a fuel element is PCB-G, and a preferred unactivated coal is PXC, both marketed by Calgon Carbon Corporation, Pittsburgh, Pennsylvania. Other preferred forms for printing and / or extrusion are prepared from pyrolyzed cotton or pyrolyzed paper.

The binders which can be used in the preparation of such a fuel element are well known in the art. A preferred binder is sodium carboxymethyl cellulose (SCMC), which can be used alone, which is preferred, or in conjunction with materials such as sodium chloride, vermiculite, bentonite, calcium carbonate, and the like. Other useful binders include rubber varieties such as guar gum and other cellulose derivatives such as methyl cellulose and carboxymethyl cellulose (CMC).

DK 174292 B1 14

Many different binder concentrations can be used. The amount of binder is preferably limited to reduce the contribution of the binder to unwanted combustion products. On the other hand, sufficient binder must be provided to hold the fuel element together during manufacture and use. The amount used will thus depend on the cohesiveness of the coal in the fuel element.

If desired, said fuel elements can be pyrolyzed after forming, e.g. ten! about 650 ° C for two hours to convert the binder to carbon, forming a fuel element of practically 100% carbon.

The fuel elements used in the present invention may also contain one or more additives to improve the burning, such as up to 5% by weight sodium chloride to improve sizing characteristics and as a glow extender. Likewise, up to approx. 5, preferably 1 to 2% by weight potassium carbonate is included to improve flammability. Additives to improve physical characteristics such as clays such as kaolin, serpentine, attapulgite and the like may also be used.

Another carbonaceous fuel element is a carbon fiber fuel which can be produced by carbonizing a fibrous precursor such as cotton, silk, paper, polyacrylonitrile and the like. Usually a pyrolysis by fraca. 650 ° C to 100 ° C, preferably at about 950 ° C for approx. 30 min. in an inert atmosphere or vacuum sufficient to produce a suitable carbon fiber with good combustion characteristics. Combustion-changing additives can also be added to these fibrous fuels.

The aerosol forming means used in the practice of the invention is physically separate from the fuel element. By physically separated, it is meant that the substrate, container or chamber containing the aerosol formed materials is not mixed with or forming part of the burning fuel element. As discussed above, this arrangement contributes to reducing or eliminating heat degradation of the aerosol-forming substance and the presence of sidestream smoke. While not part of the fuel, the aerosol forming member is in conductive heat exchange relationship with the fuel element and preferably adjoins or is adjacent to the fuel element.

It is preferred that the aerosol forming member includes one or more heat-stable materials carrying one or more aerosol forming substances. As used herein, a heat-resistant automotive material is one that can withstand the high temperatures, e.g. 400 ° C to 600 ° C, which occurs close to the fuel without decomposition or burning. The use of such material is believed to help preserve the aerosol's simple "smoke" chemistry, as evidenced by the lack of Arnes activity in the preferred embodiments. Although not preferred, other aerosol forming means, such as microcapsules which can be supplied by heat, or solid aerosol forming substances, are within the scope of the present invention, provided that they can release sufficient aerosol forming vapors to adequately resemble tobacco smoke.

Heat-stable materials which can be used as a substrate or which support the aerosol-forming mass are well known to those skilled in the art. Suitable substrates should be porous and able to retain an aerosol-forming compound when not in use and capable of releasing a potential aerosol-forming vapor when heated by the fuel element.

Useful thermostable materials include thermostable adsorbent carbon such as porous grade carbon, graphite, active or inactive carbon, and the like. Other suitable materials include inorganic solids such as ceramics, glass, aluminum, vermiculite, clays such as bentonite and the like. The currently preferred substrate materials are carbon felt, fiber, and mats, activated carbon and porous carbon forms such as PC-25 and PG-60 available from Union Carbide as well as SGL coal available from Calgon.

Depending on the aerosol forming means used herein, its composition and design can generally be selected from particulate material, fibrous material, porous blocks, solid blocks with one or more axially extending channels and the like and the like. Substrates, especially particulate masses, may be placed in a container preferably formed from a metal foil.

The aerosol forming member used in the invention is usually located no more than about.

60 mm, preferably not more than 30 mm and preferably not more than 15 mm from the ignition end of the fuel element. The aerosol forming member may vary in length from about. 2 mm to approx. 60 mm, preferably from approx. 5 mm to 40 mm and preferably from ca. 20 mm to 35 mm. If a non-particulate substrate is used, it may have one or more holes to increase the surface area of the substrate and to increase the air flow and heat transfer.

The aerosol-forming substance or substances used in connection with the invention should be capable of forming an aerosol at the temperatures found in the aerosol-forming member when heated by the burning fuel element. Such substances will preferably be composed of carbon, hydrogen and oxygen, but they may also include other substances. The aerosol forming substances may be in solid, semi-solid or liquid form. The boiling point of the substance and / or substance mixture can vary up to about 500 ° C. Substances with these characteristics include polyvalent alcohols such as glycerine and propylene glycol, as well as aliphatic esters of mono-, di-, or polycarboxylic acid such as methyl stearate, dodecanedioate, dimethyl tetradodecanedioate and others.

It is preferred that the aerosol forming substances include a mixture having a substance having a high boiling point and low vapor pressure, and a substance having a low boiling point and high vapor pressure. At the first suction, the low boiling substance will provide the majority of the first aerosol, while the high boiling substance will provide the majority of the aerosol as the temperature of the aerosol forming member increases.

The preferred aerosol forming substances are polyhydric alcohols or mixtures of polyhydric alcohols. Particularly preferred aerosol formers are selected from glycerine, propylene glycol, triethylene glycol or mixtures thereof.

17 DK 174292 B1

The aerosol-forming substance may be dispersed on or in the aerosol-forming means at a concentration sufficient to penetrate or coat the substrate, carrier or container. Eg. For example, the aerosol-forming substance can be applied at full strength or in a dilute solution by dipping, spraying, steam depositing or similar procedures. Solid aerosol forming components can be incorporated into the substrate and evenly distributed throughout the preparation prior to formation. While the amount of aerosol-forming substance will vary from carrier to carrier and from aerosol-forming substance to aerosol-forming substance, the amount of liquid aerosol-forming substances can generally range from about 1 to about 3%.

20 mg to approx. 120 mg, preferably from ca. 35 mg to approx. 85 mg and especially from ca. 45 mg to approx. 65 10 mg. As much as possible of the aerosol generator carried on the aerosol forming body should be provided to the user as WTPM. Preferably delivered over approx. 2% by weight, preferably above approx.

15% by weight and more preferably about 20% by weight aerosol generator carried on the aerosol forming member to the user as WTPM.

The aerosol forming agent may also include one or more volatile flavoring agents such as menthol, vanillin, artificial coffee, tobacco extracts, nicotine, caffeine, liqueurs and other agents which give the aerosol flavor. This may also include other desired volatile solid or liquid materials.

As noted above, the smoking product of the invention may also include a charge or plug of tobacco which may be used to add tobacco flavor to the aerosol. It is preferred that the tobacco be placed at the mouth of the aerosol forming organ or it may be mixed with the carrier for the aerosol forming substance. Flavors may also be included in the product to add flavor to the aerosol supplied to the user.

If a tobacco charger is used, hot vapors pass through the tobacco bed to extract and evaporate the volatile components of the tobacco without burning the tobacco.

25 The user of this smoking product thus receives an aerosol containing the qualities and flavors of natural tobacco without the combustion products produced by a known cigarette.

DK 174292 B1 18

Alternatively, these optional substances may be placed between the aerosol forming member and the mouth end, such as in a separate substrate or chamber in the duct leading from the aerosol forming member to the mouth end or in the optional tobacco batch. If desired, these volatiles may be used in place of part or all of the aerosol-forming substance such that the article supplies a non-aerosol flavoring agent or other materials to the user.

Products of this kind, and as described herein, may be used or may be modified to provide drug administration products, for the administration of volatile pharmacologically or physiologically active materials such as ephidrine, metaproterenol, terbutaline or similar substances.

The thermally conductive portion preferably used in the practice of this invention is typically a metal foil, such as aluminum foil, which varies in thickness from less than about 10 microns. 0.01 mm to approx. 0.1 mm or more. The thickness and / or type of conductive material can be varied to achieve in reality any desired degree of heat transfer. As shown in the illustrated embodiments, the thermally conductive portion preferably touches or overlaps a portion of the fuel element and aerosol forming member and may form the container enclosing the aerosol forming substance.

Insulating parts which may be used in accordance with the present invention generally comprise inorganic or organic fibers, such as those made of glass, aluminum, silica, vitreous materials, mineral wool, carbon, silicones, boron and organic polymers, cellulose substances and the like including mixtures of these materials. Non-fiber-containing insulating materials such as silicon aerogel, pearlite, glass and the like formed in mats, strips or other forms can also be used. Preferred insulating parts are resilient to help simulate the feel or grip of a known cigarette. These materials primarily act as an insulating jacket and retain a significant portion of the heat generated by the burning fuel element and direct it to the aerosol forming member. As the insulating sheath adjacent to the burning fuel element becomes hot to a limited extent, it can also conduct heat towards the aerosol forming member.

19 DK 174292 B1

Currently preferred insulating materials include ceramic fibers such as glass fibers. Two particularly preferred glass fibers are obtained from Manning Paper Company, Troy, New York under the designations Manniglas 1000 and Manniglas 1200. Generally, the insulating fibers are wrapped around at least one portion of the fuel element or other desired portion of the article until a final diameter of from ca. 7 to 8 mm. Thus, the preferred thickness of the insulating layer is from approx. From about 0.5 mm to 2.5 mm and preferably from ca. 1 mm to 2 mm. Whenever possible, glass fiber materials having a low softening point, e.g. below 650 ° C.

When the insulating member is fibrous, it is preferred to use a barrier member at the mouth of the article. Such a barrier member comprises an annular portion of high density cellulose acetate tow 10 abutting the fibrous insulating member and sealed, preferably at the mouth end with e.g. glue to block airflow through the bladder.

In most embodiments of the invention, the fuel / aerosol forming organ combination will be attached to an mouthpiece such as a foil lined with paper or cellulose acetate / plastic tube as illustrated in the drawing, although an mouthpiece may be delivered separately, e.g. in the form of a cigarette holder. This element of the article provides the channel which, via channels, directs the evaporated aerosol forming substance into the user's mouth. Because of its length, preferably approx. 50-60 mm or more, this also keeps the hot fire cone away from the mouth and the user's fingers.

Suitable nozzles should be inactive with respect to the aerosol-forming substances, should have a water or liquid-tight inner layer, should provide minimal aerosol loss upon condensation or filtration, and should be able to withstand temperatures at the interface with the other elements of the product. Preferred mouth end pieces include the cellulose acetate tube used in the embodiments shown in FIG. 1-4. Other suitable mouthpieces are obvious to those skilled in the art.

The mouthpieces of the invention may optionally include a "filter" tip used to give the item the appearance of a known filter cigarette. Such filters include low density cellulose acetate filters and hollow or screen bearing plastic filters such as those made of polypropylene. Furthermore, the entire length of the product or any part thereof may be wrapped with cigarette paper.

The aerosol produced by the preferred products of the invention is chemically simple, consisting essentially of atmospheric air, carbon oxides, the aerosol carrying any desired flavoring or other volatile substances, water and trace amounts of other materials.

The wet total particulate matter (WTPM) produced by the preferred product of the present invention has no mutagenic activity as measured by the Ames sample, i.e. that there is no significant dose-response relationship between the WTPM of the present invention and the number of relapses (revertants) present in standard sample microorganisms exposed to such products. According to the authors of the Arnes test, a significant dose-dependent reaction indicates the presence of mutagenic materials in the tested products. See Ames et al., Mut. Res., 31: 347-364 (1975); Nagas et al., Mut. Res. 42: 335 (1977).

A further good obtained from the preferred embodiments of the present invention is the relative lack of ash produced during use over ash from a known cigarette. When the preferred carbon fuel source is burned, it is essentially converted to carbon oxides with relatively little ash formation and thus there is no need to discard ash during use of the product.

The smoking product of the present invention is further illustrated with reference to the following example which will aid in understanding the present invention but which is not to be considered as limitations thereof. All percentages stated herein are, unless otherwise indicated, by weight. All temperatures are given in C ° and are not corrected. In all cases the smoking products have a diameter of approx. 7 to 8 mm, ie the diameter of a known cigarette.

21 DK 174292 B1

Example 1

A modified version of the smoking product shown in FIG. 4 was prepared as follows: A 9.5 mm long carbon fuel source having a diameter of 4.5 mm and a longitudinal channel with a diameter of 1 mm was extruded from a mixture of 10% SCMC, 5% potassium carbonate, and 5.85. % carbonized paper mixed with 10% water. The mixture had a dough-like consistency and was fed into an extruder. The extruded material was cut to lengths after drying at 80 ° C overnight. The macro capsule was made of a 22 mm long piece of 0.0089 mm thick aluminum foil formed into a 4.5 mm inner diameter cylinder. The macro capsule was filled with (a) 70 mg of vermiculite containing 50 mg of a 1: 1 mixture 10 of propylene glycol and glycerine and (b) 30 mg of burley tobacco to which 6% glycerine and 6% propylene glycol were added. The fuel source and macrocapsule were assembled by inserting the fuel source approx. 2 mm at the end of the macro capsule. A 35 mm long polypropylene tube with an inner diameter of 4.5 mm was inserted into the other end of the macrocapsule. Thus, the fuel source, macrocapsule and polypropylene tube were assembled to form a 65 mm long segment of 4.5 mm diameter. This segment was wrapped with several layers of Manniglas 1000 from Manning Paper Company until a circumference of 24.7 mm was obtained. The unit was then combined with a 5 mm cellulose acetate filter and wrapped with cigarette paper.

When smoked under FTC conditions, the product delivered 8 mg of wet total particulate matter during the first three sucks; 7 mg WTPM during suction 4-6 and 5 mg WTPM during suction 7-9. The total aerosol delivered over 9 suction was 20 mg. When placed horizontally on a piece of wipe-like paper, the wipe-like paper was neither ignited nor sweated by the item.

Claims (6)

22 DK 174292 B1 A smoking product comprising a fuel element (10) at the ignition end of the smoking device and a physically separate aerosol forming member (12) containing at least one aerosol forming substance and arranged to receive heat from the fuel element (10) during smoking and coupled to the fuel element (10), the aerosol forming member (12) being arranged longitudinally behind the fuel element (10), characterized in that the smoking product further comprises an elastic insulating member (86) which is at least 0.5 mm thick and encloses substantially the entire length of the fuel element ( 10). Smoking product according to claim 1, characterized in that the insulating part (86) surrounds at least one part of the aerosol forming member (12). Smoking product according to claim 1 or 2, characterized in that the fuel element (10) and the aerosol forming member (12) are in conductive heat exchange communication with each other. Smoking product according to one of claims 1 to 3, characterized in that the fuel element 15 (10) is less than 30 mm long. Smoking product according to one of claims 1 to 4, characterized in that the insulating part comprises inorganic fibers. Smoking product according to one of claims 1 to 5, characterized in that the insulating part is wrapped in cigarette paper. 20