FI78818B - CIGARETTE LIKE ROEKNINGSPRODUKT. - Google Patents

Description

1 78818

Cigarette-like smoking product. - Cigarettliknande röknings-produkt.

The present invention relates to a cigarette-shaped smoking article or device according to the preamble of claim 1, which forms a tobacco smoke-like aerosol and which preferably contains substantially smaller amounts of incomplete combustion and pyrolysis products than a conventional cigarette normally forms.

Many smoking products have been developed over the years, especially in the last 20-30 years, but none of these products have ever achieved commercial success.

Despite decades of interest and business, there is still no smoking product on the market that has the advantages of conventional cigarettes without producing significant amounts of the incomplete combustion and pyrolysis products of a conventional cigarette.

The invention relates to a cigarette-like smoking article comprising: a carbonaceous fuel element, a physically separate aerosol generating member containing an aerosol generating material interposed between the fuel element and the mouthpiece of the article, and a physically discrete tobacco-containing mass and characterized by at least a physically discrete tobacco part of the aerosol generating part.

Applicant's prior application No. 853486 discloses a cigarette-like smoking article comprising a carbonaceous fuel element and a physically separate aerosol generating member containing an aerosol forming material interposed between the fuel element and the mouthpiece of the article. However, this application does not disclose the placement of a separate tobacco mass in a location surrounding the aerosol generating member.

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Placing the tobacco-containing mass around the aerosol-forming portion allows the tobacco-containing mass to receive considerable heat from the aerosol-forming portion. In addition, such location of the tobacco allows the smoking product of the invention to have the aromas and feel of a conventional tobacco burning cigarette. In addition, such a location provides for the sweeping of vapors from the carbonaceous fuel and / or aerosols from the aerosol generating component through the tobacco-containing mass and thus the release of volatile flavorings and flavor components therefrom.

U.S. Patent No. 3,258,015 discloses a tobacco-containing mass surrounding an aerosol generating member. In this publication, however, the tobacco-containing pulp is in itself a fuel for the smoking article. It does not contain any tobacco-containing mass separate from the fuel, which surrounds the aerosol generating part. This publication only discloses a fuel which may itself be tobacco, which surrounds the aerosol generating part. No separate fuel is shown and, in addition, the fuel disclosed in the reference is not carbonaceous as in the smoking article of the present application.

The aerosol generating member preferably includes a separate conductive container in a heat exchange relationship with the fuel element and at least a portion of the fuel element is surrounded by a flexible insulating sheath to reduce radial heat loss. When ignited, the fuel element generates heat which is used to vaporize the aerosol-forming materials in the aerosol-forming section. Especially during inhalation, these volatile materials retract towards the mouth end and further into the user's mouth in the same manner as the smoke of a conventional cigarette.

Il 3 78818

The smoking articles of the invention are capable of generating significant amounts of aerosol both in the initial phase and throughout the life of the article and provide the user with the impressions and benefits of smoking a cigarette. The aerosol produced by the aerosol generating member is formed without significant thermal decomposition and preferably transfers to the user significantly less amounts of pyrolysis and incomplete combustion products than a conventional cigarette normally produces.

The invention uses a small high density combustible fuel element having a length of less than about 30 mm, preferably less than about 20 mm, and a density of at least about 0.5 g / cm 2, more preferably at least about 0.7 g / cm 2 as measured, for example, by mercury displacement. Suitable fuel elements may be molded or extruded from the comminuted or remixed tobacco and / or tobacco substitute and preferably contain combustible carbon. Preferred fuel elements are also provided with one or more longitudinal channels, more preferably 5-9 channels or more, to help direct heat transfer from the combustible fuel element to the aerosol-forming materials.

In addition, at least a portion of the fuel element is preferably provided with a surrounding insulating member, such as a sheath formed of insulating fibers, the sheath being preferably a flexible, non-combustible material and at least 0.5 mm thick. This part reduces the radial heat loss and helps to retain and direct heat from the fuel element towards the aerosol generating part and further reduces the fire risk of the fuel. The preferred insulating member surrounds at least a portion of the fuel element and preferably at least a portion of the aerosol generating member, which helps to mimic the feel of a conventional cigarette.

The materials used to insulate the fuel element and the aerosol generating member may be the same or different materials.

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Because the fuel element is relatively short, the hot, flammable fire cone is always close to the aerosol generating member, maximizing heat transfer thereto and the resulting aerosol production, especially in embodiments with a multi-channel or multi-channel fuel element, heat conductor section, and insulator section. The relatively high density fuel material is used to ensure that the small fuel element burns long enough to mimic the burning time of a conventional cigarette and that it generates sufficient energy to generate the required amounts of aerosols. Because the aerosol-forming agent is physically separate from the fuel element, it is exposed to substantially lower temperatures than the temperatures in the combustible fire cone, thus minimizing the potential for thermal decomposition of the aerosol-forming agent.

The smoking article of the present invention is normally provided with an oral main body having, for example, a longitudinal channel member for transferring volatile material generated by the aerosol generating member to the user. The mouthpiece preferably includes a flexible outer portion, such as an annular cellulose acetate pad, to trace the feel of a conventional cigarette. The overall dimensions of the product are preferably the same as those of a conventional cigarette, and therefore the mouthpiece and aerosol delivery portion usually cover about half or more of the length of the product. Alternatively, the fuel element and aerosol generating member may be made with a built-in mouthpiece or aerosol transfer member for use with a separate, disposable or reusable mouthpiece.

The smoking article of the present invention includes a dose or stopper of tobacco that can be used to enhance the taste of the tobacco into the aerosol. The annular tobacco portion is placed around the perimeter of the aerosol generating portion, where it also acts as an insulating portion and helps to mimic the taste and feel of a conventional cigarette. Flavoring agents may also be added to the product to flavor or otherwise alter the aerosol to the user.

The smoking articles of the invention normally use substantially less fuel by volume and preferably by weight than conventional cigarettes to produce acceptable aerosol amounts. In addition, the aerosol to the user normally has less pyrolysis and incomplete combustion products due to the non-degradable aerosol from the aerosol generating member, and since in particular longitudinal channel embodiments that the fuel element contains tobacco or other cellulosic material.

In this text, and only in connection with this patent application, the word "aerosol" is used to cover vapors, gases, both visible and invisible particles, and the like, and in particular those ingredients which appear "smoky" to the user when heat from a combustible fuel element acts on aerosol generators or other products. substances. As defined in this way, the term "aerosol" also includes volatile flavoring agents and / or pharmacologically or physiologically active substances, whether or not they form a visible aerosol.

As used herein, the term "conductive heat exchange ratio" means the physical arrangement or arrangement of an aerosol generating member and a fuel element by which heat is transferred from the combustible fuel element to the aerosol generating member over substantially the entire combustion cycle of the fuel element. The conductive heat exchange ratio can be achieved by placing the aerosol generating member in contact with the fuel element and very close to the combustible portion of the fuel element and / or utilizing the conductor portion to transfer heat from the combustible fuel to the aerosol generating member. Preferably, both methods can be used to provide conductive heat transfer.

As used herein, the term "insulating member" means any material that acts primarily as an insulator. It is preferred that these materials do not burn during use, but may include slow-burning carbon and the like, and in particular materials that melt during use, such as low temperature glass fiber grades. Suitable insulators have a thermal conductivity of less than about 0.05, preferably less than about 0.02, most preferably less than about 0.005, measured in g-cal / (sec) (cm 2) (cm 2) (C ° / cm). See Hackh's Chemical Dictionary, 34 (4th edition, 1969) and Lange's Handbook of Chemistry, 10, 272-274 (11th edition, 1973).

The smoking article of the present invention will be described in more detail in the following detailed description of the invention with reference to the accompanying drawings, in which:

Figures 1-2 are longitudinal sections of various embodiments of the invention;

Fig. 1A is an end view of the embodiment of Fig. 1;

Fig. 1B is an enlarged end view of a metal container used in the embodiment of Fig. 1; 7 78818

Figure 2A is an end view of a channel or duct arrangement of a fuel element suitable for use in embodiments of the invention;

Figure 2B is a longitudinal sectional view of a preferred fuel cell duct structure well suited for use in embodiments of the invention.

The embodiments shown in Figures 1 to 2 include a flexible insulating sheath that surrounds or encloses the fuel element to insulate and concentrate heat therein. These embodiments also reduce the risk of fire in a burning cone of fire and, in some cases, help to achieve the feel of a conventional cigarette.

Figure 1 shows an embodiment in which a 10-15 mm long fuel element 10 is wrapped in a glass fiber insulating sheath 72 and the aerosol generating member 12 is surrounded by a tobacco layer 88. The glass fibers used in this embodiment preferably have a softening temperature below about 650 ° C. Examples are test fibers 6432 and 6437, manufactured by Owens-Corning, Toledo, Ohio. The fiberglass and tobacco layers are each wrapped in a filter wrapper 85, such as Ecusta 646, and joined together by a cigarette paper wrapper 89, such as 8,78818 7Θ0-63-5 or P 878-16-2, manufactured by Kimberly-Clark.

In this embodiment, the metal capsule 90 extends over the rear end of the fuel element by 3 to 4 mm so that it is about 6 to 12 mm from the ignition end and the back of the capsule 90 is folded at an angle, as shown in Figure Ib.

An opening 91 is formed at the mouth end of the capsule in the center of the capsule. Four additional openings are formed at the transition points between the crimped and non-crumpled portions of the capsule. Alternatively, the cross-section of the back of the capsule may be rectangular or square instead of lugs, or a simple tubular capsule with a crimped mouth end may be used, which may or may not have circumferential openings 92.

At the mouth end of the tobacco layer 88 is a mouthpiece 40 comprising an annular cellulose acetate sheath 42, a plastic tube 44, a low efficiency filter portion 45, and cigarette paper layers 85 and 89. The mouthpiece 40 is connected to a jacketed the end is separated from the capsule 90. In this case, the hot vapors flowing through the openings 92 pass through the tobacco layer 88 where the volatile components of the tobacco evaporate or become extracted and then pass to the passage 18 where the tobacco layer abuts the cellulose acetate sheath 42.

In such embodiments with low density fuel insulating jackets 72, some air and gases pass through the jacket 72 and on to the tobacco layer 88. In this case, peripheral openings 92 may not be required in the capsule to extract tobacco flavor from the tobacco layer 88.

In the embodiment of Figure 2, the sheath 94 contains tobacco or a mixture of tobacco and special fibers, such as glass fibers. As shown, the tobacco sheath or layer 94 extends slightly over the mouth end of the metal container 9 78818. Alternatively, it may extend the entire length of the product to the filter at the mouth end. In such embodiments, the periphery of the container 96 is preferably provided with one or more longitudinal slots 99 (preferably two slits 180 ° apart) so that vapors from the aerosol former 12 pass through the annular tobacco portion surrounding the aerosol former 12 to extract tobacco aromas prior to passage 18.

As shown, at the fuel element end of the sheath 94, the tobacco is compressed. This reduces the air flow through the tobacco, thus reducing its combustion power. In addition, the container 96 assists in extinguishing the tobacco by acting as a heat sink. This heat sinking effect helps to suppress the combustion of the tobacco surrounding the capsule and likewise helps to distribute the heat evenly over the tobacco around the awrosol forming part 12, thus promoting the release of tobacco flavorings. In addition, it may be advantageous to treat a portion of the cigarette paper 85, 89 near the rear end of the fuel with, for example, sodium silicate to aid in extinguishing the tobacco so that it does not burn significantly over the visible portion of the fuel element. Alternatively, the tobacco itself may be treated with a combustion control agent to prevent combustion of the tobacco surrounding the aerosol former 12.

Upon ignition of any of the embodiments described above, the fuel element burns to generate heat which is used to vaporize the aerosol-forming material 38 or materials in the aerosol-forming section 12. These volatile materials then retract towards the mouth-side end, especially during suction and further into the user's mouth in the same manner as the smoke of a conventional cigarette.

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Because the fuel element is relatively short, the hot, combustible cone of fire is always close to the aerosol generating member, thus maximizing heat transfer to the aerosol generating member and tobacco portions and further aerosol and tobacco flavor production, especially when using the preferred heat conducting member. Because the fuel element is short, the product never has a long non-combustible fuel component that would act as a heat sink in the usual thermal difference sol products in a common manner. The small amount or source of fuel also minimizes the amount of incomplete combustion or pyrolysis products, especially in those embodiments that contain carbon and / or multiple channels.

Heat transfer and therefore aerosol uptake can also be improved by using ducts or passages extending through the fuel which draw hot air into the aerosol generator, especially during suction. Heat transfer is also enhanced by a preferred heat conductor portion spaced apart or spaced from the ignition end of the fuel cell so as not to interfere with ignition and combustion of the fuel while avoiding ugly protrusion of the heat conductor portion even after use. In addition, the preferred insulating member tends to enclose, direct and concentrate heat towards the center of the product, thus increasing the heat transferred to the aerosol-forming agent.

Because the aerosol-forming material is physically separated from the fuel element, it is exposed to substantially lower temperatures than those present in a combustible cone of fire. This minimizes the potential for thermal decomposition of the aerosol former and the associated bad taste. This also results in aerosol formation during aspiration and, in addition, minimal aerosol formation from the aerosol generating member during consumption.

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In preferred embodiments of the invention, the short fuel element, the retracted heat conductor portion, the insulator portion, and the pathways in the fuel, together with the aerosol generator, form a system capable of generating substantial amounts of aerosol and possibly tobacco aroma with virtually every aspiration. The proximity of the fire cone to the aerosol former after a few aspirations, together with the conductor portion, the insulator portion and the multiple passages in the fuel element, provides good heat transfer both during aspiration and during the relatively long boiling time between aspirations.

Without wishing to be bound by theory, it appears that the aerosol generating member remains at a relatively high temperature between aspirations and that the additional heat generated during aspirations, which is greatly increased by the preferred pathways in the fuel element, becomes primarily used to vaporize the aerosol generating material. This increased heat transfer results in a more efficient use of available fuel energy, reduces the amount of fuel required, and assists in the initial formation of aerosol.

In addition, by appropriately selecting the composition of the fuel cell, the number, size, shape and placement of the fuel cell paths, the insulating jacket, the cover paper and the heat conductor section, it is possible to substantially control or adjust the combustion properties of the fuel source. In this way, the transfer of heat to the aerosol former is well controlled and this in turn can be used to change the amount of suction and / or the amount of aerosol to the user.

In general, the combustible fuel elements used to practice the invention are less than about 30 mm long. The length of the fuel element is preferably about 20 mm or less, more preferably about 15 mm or less. The diameter of the fuel element 78818 is preferably about 8 mm or less, preferably about 3 to 7 mm, and more preferably about 4 to 6 mm. The density of the fuel elements used herein varies from about 0.5 g / cm 3 to about 1.5 g / cm 3 as measured, for example, by mercury displacement. The density is preferably greater than 0.7 g / m 3, more preferably greater than 0.8 g / cm 3. In most cases, a high density material is preferred because it ensures that the fuel element burns long enough to mimic the burning time of a conventional cigarette and generates sufficient energy to generate the required amount of aerosol.

The fuel elements used herein are preferably molded or extruded from comminuted tobacco, remixed tobacco or tobacco substitute materials, such as modified cellulosic materials, degraded or pre-pyrolyzed tobacco and the like. Suitable materials are described, e.g., in U.S. Pat. in U.S. Patent No. 4,347,855 to Lanzilotti et al., U.S. Pat. U.S. Patent No. 3,931,824 to Miano et al., and U.S. Pat. in U.S. Patent Nos. 3,885,574 and 4,008,723 to Bortwick et al. and Sittig, Tobacco Substitutes, Noyes Data Corp. (1976). Other suitable combustible materials may be used as long as they burn long enough to mimic the burning time of a conventional cigarette and generate sufficient heat for the aerosol generating member to produce the desired amount of aerosol from the aerosol generating material.

Preferred fuel elements normally contain combustible carbon materials obtained, for example, by pyrolysis or carbonization of cellulosic materials, such as wood, cotton, rayon, tobacco, coconut, paper, and the like. In most cases, combustible carbon is preferred due to its high heat generation capacity and because it produces only minimal amounts of incomplete combustion products. The carbon content of the fuel element is preferably about 20 to 40 weight percent or more.

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The most preferred fuel elements in the practice of this invention are carbonaceous fuel elements (i.e., predominantly carbonaceous fuel elements) described and elucidated in co-pending patent applications No. 650,604, filed September 14, 1985, and No. 769,532, filed August 26, 1985. Carbonaceous fuel elements are particularly advantageous because they produce as little pyrolysis and incomplete combustion products as possible, produce little or no visible sidestream smoke and as little ash, and also have good heat capacity. In particularly preferred embodiments, the aerosol delivered to the user does not have a significant mutagenic effect as measured by the Ames test. See Ames et al., Mut. Res., 31: 347-364 (1975); Nagas et al., Mut. Res., 42: 335 (1977).

Combustion additives or combustion regulators may also be added to the fuel to provide suitable combustion and glow properties. If desired, fillers such as diatomaceous earth and binders such as sodium carboxymethylcellulose (SCMC) may also be added to the fuel. Flavorings and fragrances, such as tobacco extracts, may also be added to the fuel to add tobacco or other flavor to the aerosol.

The fuel element is preferably provided with one or more longitudinally extending paths. These pathways help to control the transfer of heat from the fuel element to the aerosol generating member, which is important to transfer sufficient heat to generate a sufficient amount of aerosol and also to avoid such a large amount of heat transfer that the aerosol generator disintegrates. In general, these pathways cause porosity and increase early heat transfer to the substrate by increasing the amount of hot gases entering the substrate. They also seek to increase the rate of combustion.

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In general, a large number of passages or channels, e.g. £-9 or more, and in particular the placement of the passages relatively far apart according to Figures 1A and 2A, provides a high convective heat transfer leading to high aerosol formation. The large number of fairways also usually ensures easy ignition.

Good convection heat transfer creates a higher CO output to the mainstream. A smaller number of passages or a denser fuel cell can be used to reduce CO levels, but such changes generally make it more difficult to ignite the fuel cell and reduce the transfer of convective heat, thereby reducing the rate and amount of aerosol flow.

However, it has been found that in closely spaced pathways where the pathways burn out or merge to form a single pathway at least at the ignition end, the amount of CO in the combustion products is generally less than that formed using the same pathway arrangement but farther apart. The optimum flow, shape, and amount of fuel cell pathways should be such that aerosol formation is uniform and abundant, ignition is easy, and CO is formed little. Various combinations have been studied for the placement / shape and / or number of pathways in the carbonaceous fuel elements used in various embodiments of the invention. In general, it has been found that fuel elements having about 5-9 passages relatively close to each other so that they burn out into one large passage at least at the fuel element ignition end appear to satisfy the requirements of the most preferred fuel element for use in this invention, especially when using preferred carbonaceous The fuel elements. However, it appears that this phenomenon also occurs with the use of various non-carbon fuel elements that can be used in the practice of the invention.

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Variables that affect the rate of fuel element pathways merging when the element burns include the density and composition of the fuel element, the size, shape, and number of paths, the distance between the paths, and their placement. For example, when using a carbon fuel source with a density of 0.85 g / cm3 with seven lanes of about 0.5 mm, the lanes should be located in the inner diameter range, i.e., the diameter of the smallest circle around the outer edge of the lanes between about 1.6 and 2.5 mm to converge into a single pathway during combustion. However, when the diameter of these seven passages is increased to about 0.6 mm, the combined inner diameter during combustion increases to about 2.1 to about 3.0 mm.

Another preferred fuel cell bus arrangement useful in embodiments of the invention is the structure shown in Figure 25, which has been found to be particularly advantageous in terms of low CO output and ease of ignition. In this preferred arrangement, the short portion at the ignition end of the fuel element is provided with a plurality of passages or channels, preferably about 5 to 9, which merge into a large cavity 97 extending to the mouth end of the fuel element. The multiple passages at the ignition end provide a large surface area that is advantageous in terms of ease of ignition and early aerosol production. The cavity may be about 30-95%, preferably more than 50% of the length of the fuel element, and ensures uniform heat transfer to the aerosol generating section and produces little CO in the main stream.

The aerosol generating member used in the practice of the invention is physically separate from the fuel element. By physically separate is meant that the substrate, container, or chamber containing the aerosol-forming materials does not mix or form part of the combustible fuel element. As previously stated, this arrangement reduces or eliminates the thermal decomposition of the aerosol-forming material and the presence of sidestream smoke. Although the aerosol generating member is not part of the fuel, it is preferably in a conductive heat exchange ratio with the fuel element and is preferably located against or adjacent to the fuel element. The conductive heat exchange ratio is more preferably provided by a heat conductor portion, such as a metal tube or foil, which is preferably pulled back or separated from the ignition end of the fuel.

The aerosol generating member preferably includes one or more heat-resistant materials that carry or support one or more aerosol-forming materials. In this context, heat-resistant material means one that can withstand high temperatures in the vicinity of the fuel, for example between 400 and 600 ° C, without decomposing or burning. The invention also encompasses other aerosol generating means, such as thermally breakable microcapsules or solid aerosol generating agents, provided that they are capable of releasing sufficient aerosol generating fumes that satisfactorily resemble tobacco smoke, but these are not preferred.

Heat-resistant materials used as a substrate or carrier for aerosol-forming materials are well known to those skilled in the art. Useful substrates should be porous and able to bind the aerosol-forming material when not in use, and further should be able to release the aerosol-forming vapor when heated by the fuel element. In particular, the particulate substrates can be placed in a container, which is preferably formed of a conductive material.

Li 17,78818 Useful heat-resistant materials include thermostable adsorbent carbons such as porous carbon grades, graphite, activated or inactive carbons, and the like. Other suitable materials include inorganic solids such as ceramics, glass, alumina, vermiculite, clays such as bentonite and the like. Preferred carbon substrate materials are porous carbons such as PC-25 and PG-60 from Union Carbid and SGL carbon from Calgon. The preferred alumina substrate is SMR-14-1896 obtained from W.R. From the Davidson Chemical Division of Grace & Co and sintered at elevated temperatures, e.g., greater than about 1,000 ° C, washed and dried prior to use.

It has been found that suitable particulate substrates can also be formed from carbon, tobacco or carbon-tobacco mixtures into compacted particles in a one-step process using a machine manufactured by Fuji Paudal KK of Japan and sold under the tradename "Marumerizer". This device is described in German Patent No. 1,294,351 and U.S. Pat. in U.S. Patent No. 3,277,520 (now republished under No. 27,214) and Japanese Patent Application Publication No. 8684/1967.

The aerosol generating member used in the invention is preferably located at a distance of at most about 40 mm, preferably at most about 30 mm and most preferably at most 20 mm from the ignition end of the fuel element. The pirosity of the aerosol former may range from about 2 mm to about 60 mm, preferably from about 5 to 40 mm, and most preferably from about 20 to 35 mm. The diameter of the aerosol generating member may vary between about 2 mm and 8 mm, preferably about 3-6 mm. If a non-particulate substrate is used, one or more holes may be formed in it to increase the surface area of the substrate and to increase airflow and heat transfer.

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The aerosol-forming material or materials used in the invention must be able to form an aerosol at the temperatures prevailing in the aerosol-forming part when the combustible fuel element heats this part. These materials preferably consist of carbon, hydrogen and oxygen, but may contain other substances. Aerosol-forming materials can be solid, semi-solid or liquid. The boiling point of the material and / or mixture of materials can be as high as about 500 ° C. Substances with these properties include polyhydric alcohols such as glycerin and propylene glycol, as well as aliphatic esters of mono-, di- or polycarboxylic acids such as methyl stearate, dodecanedioate, dimethyltetradodecanedioate and others.

Preferred aerosol-forming materials are polyhydric alcohols or mixtures of polyhydric alcohols. Particularly preferred aerosol generators are glycerin, propylene glycol, triethylene glycol or mixtures thereof.

The aerosol-forming material may be dispersed in or within the aerosol-forming portion in sufficient concentration to saturate or spread on the substrate, carrier, or container. For example, the aerosol-forming agent can be used as a full-strength or dilute solution by dipping, spraying, vapor-separating, or the like methods. The solid aerosol-forming ingredients can be mixed into the substrate and evenly distributed therein prior to formation.

Although the load on the aerosol-forming material varies depending on the carrier and the aerosol-forming material, the amount of liquid aerosol-forming materials is generally in the range of about 20 mg to 120 mg, preferably about 35 mg to 85 mg, and most preferably about 45 mg to 65 mg. As much of the aerosol generator carried by the aerosol generating member as possible should be transferred to the user as a WTPM. Preferably, greater than 19 7881 δ about 2% by weight, more preferably greater than about 15% by weight, and most preferably greater than about 20% by weight of the aerosol former in the aerosol generating member is transferred to the user as WTPM.

The aerosol-forming component may also contain one or more volatile flavoring agents, such as, for example, menthol, vanillin, artificial coffee, tobacco extracts. nicotine, caffeine, solutions and other substances that impart flavor to the aerosol. It may also include other desired volatile solids or liquids. Alternatively, these optional agents may be placed between the aerosol generating member and the oral end, for example, as a separate substrate or as a container in the pathway leading from the aerosol generating member to the oral end or as a dose of tobacco. If desired, these volatile substances may be used in place of or as part of the aerosol-forming material so that the product imparts a flavor to the user of a non-aerosol or other material.

A particularly preferred aerosol-forming member comprises the above-mentioned alumina substrate containing spray-dried tobacco extract, tobacco flavor control agents such as Levuic acid, one or more flavoring agents, and an aerosol-forming material such as glycerin. This substrate can be mixed with compacted tobacco particles, such as those obtained with a "Marumerizer", and which particles can also be impregnated with an aerosol-forming material.

Products such as those set forth herein may be used or converted into usable drug delivery devices, and may provide volatile pharmacologically or physiologically active agents such as ephedrine, metaproterenol, tert-butaline, or the like.

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The tobacco-containing material may include any type of tobacco available to the professional, such as Burley, flue gas-cured tobacco, Turkish tobacco, blended tobacco, extruded or condensed tobacco blends, tobacco-containing sheets, and the like. A mixture of tobacco grades can be advantageously used to produce flavor variations. The tobacco-containing material may also contain conventional tobacco additives such as fillers, peelers, reinforcing agents such as glass fibers, wetting agents and the like. Flavoring agents as well as flavoring agents may also be added to the tobacco material.

The heat conductor portion preferably used in the practice of this invention is typically a metal (e.g., aluminum) tube, sheet, or foil having a thickness ranging from less than about 0.01 mm to about 0.2 mm or more. The thickness, shape, and / or type of conductive material (e.g., other metals or grafoil from Union Carbid) can vary to achieve virtually any desired degree of heat transfer. In general, the heat conductor portion should be far enough away so as not to interfere with the ignition of the fuel element, but close enough to the heat-conducting head to provide conductive heat transfer during the first and mid-suction operations.

The heat conductor portion preferably forms a conductive container that encloses the aerosol-forming materials.

Alternatively, a separate conductive container may be included, especially in those embodiments where particulate substrates or semi-liquid aerosol-forming materials are used. Not only does the conductive container act as a container for aerosol-forming materials, it also improves the distribution of heat to the aerosol-forming materials and the surrounding tobacco layer and prevents the aerosol-former from migrating to other components of the product. The container also provides a means for controlling the pressure drop through the product by changing the number, size and / or position of the passages through which the aerosol former passes to the mouth end of the product. In addition, the container may be provided with circumferential openings or slots for regulating and controlling the flow of vapors through the tobacco. The use of a container also simplifies the manufacture of the product by reducing the number of parts and / or manufacturing steps required.

The insulating parts used in carrying out the invention can advantageously be formed as one flexible sheath of one or more layers of insulating material. This sheath is preferably at least 0.5 mm thick, more preferably at least 1 mm thick, and most preferably about 1.5 to 2 mm thick. The jacket preferably extends over the fuel element more than half its length. More preferably, it extends or covers all or part of the entire outer circumference of the fuel element and the aerosol generating portion. As shown in the embodiment of Figure 1, different materials can be used to insulate the two components of the product.

The insulating parts used in accordance with the present invention are generally inorganic or organic fibers made of, for example, glass, alumina, silica, vitreous materials, rock wool, carbon, silicon, boron, organic polymers, cellulosic materials, and the like, including mixtures of these materials. Likewise, non-fibrous insulating materials such as silica aerogel, perlite, glass and the like formed into mats, strips or other shapes can be used. Preferred insulating members are flexible to mimic the feel of a conventional cigarette. Preferred insulating materials should melt during use and have a softening temperature below about 650-700 °. Preferred insulation materials should also not burn during use. However, slow-burning coals and similar materials can be used. These materials act primarily as an insulating jacket, retaining and directing a substantial portion of the heat generated by the combustible fuel element to the aerosol generating portion. Because the insulating jacket heats up adjacent to the combustible fuel element, it can also conduct heat to a limited extent toward the aerosol generating member.

Currently preferred fuel cell insulation materials are ceramic fibers such as glass fibers. Two suitable glass fibers are available from Manning Paper Company, Troy, New York, under the tradenames Manniglas 1000 and Manniglas 1200. Preferred glass fiber materials have a low softening point, e.g., less than about 650 °, using ASTM Test Method C 338-73. Preferred glass fibers are experimental materials manufactured by Owens-Cordning, Toledo, Ohio under the tradenames 6432 and 6437, which have a softening point of about 640 ° and which melt during use.

Many commercially available inorganic fibers are made with a binder, e.g., PVA, that maintains the structure intact during processing. These binders give off a bitter taste when heated and should be removed, for example, by heating in air at a temperature of about 650 ° for about 15 minutes before use. If desired, about 3% by weight of pectin can be added to the fibers to mechanically strengthen the sheath without causing a bitter taste.

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Alternatively, the insulating material may be replaced in whole or in part by either loosely packed or tightly packed tobacco. The use of tobacco to partially or completely replace the insulating sheath further causes the aromas of the tobacco to shift into the main stream of aerosol and provide a tobacco-flavored side stream in addition to acting as an insulator. The layer or sheath acts as a non-combustible insulator while imparting tobacco aromas to the main aerosol stream. In the embodiment where the tobacco surrounds the fuel, the tobacco is preferably consumed only to the extent that the fuel source is consumed, i.e. up to the point of contact between the fuel element and the aerosol generating part. This can be accomplished by squeezing the tobacco around the fuel element and / or using a conductive heat sink as in the embodiment shown in Figure 2. This can also be accomplished by treating the cigarette paper wrapper and / or tobacco materials to extinguish the tobacco at the point where it enters the aerosol generating member.

When the insulating part consists of fibrous materials other than tobacco, a closure part can be used between the insulating part and the mouth end of the product. One such closure member is an annular high density cellulose acetate sheath which abuts the fibrous insulating member and is sealed at both ends, for example with an adhesive, to prevent airflow from passing through the mandrel.

In various embodiments of the invention, the fuel / aerosol generating member assembly is attached to a mouthpiece 40, such as foil lined paper or cellulose acetate / plastic tubes 44 shown in the figures, although the mouthpiece may be formed separately, e.g., in the form of a cigarette holder. This part of the product forms a passage 1Θ which directs the vaporized aerosol-forming materials into the user's mouth. It is preferably about 35 to 50 mm or more in length and therefore also keeps the hot cone of fire away from the user's mouth and fingers and allows the hot aerosol 24 hours enough to form and cool before it enters the user.

Suitable mouthpieces should be inert to aerosol-forming agents, may have a water- or liquid-tight inner layer, should minimize aerosol loss due to condensation or filtration, and should be able to withstand the temperature at the interface between them and other parts of the product. Preferred mouthpieces include a cellulose acetate tube that acts as a flexible outer member and aids in mimicking the feel of a conventional cigarette at the mouth end of the product. Other suitable mouthpieces will be apparent to those skilled in the art.

Mouthpieces useful in the products of the invention may include an optional "filter" 45 used to impart the appearance of a conventional filter cigarette to the product.

The product may be coated along its entire length or any part thereof may be coated with cigarette paper 85.89. Preferred papers are those that do not ignite at the fuel cell end during combustion of the fuel cell. In addition, the paper should have controlled cooking properties and should form a gray, cigarette-like ash. When an insulating jacket is used, the paper burns away from the jacketed fuel element, resulting in maximum heat transfer due to the fact that the air flow to the fuel source is not restricted. However, papers may be used which remain wholly or partially intact when exposed to heat from a combustible fuel cell 25 7 8 8 1 8. Such papers provide a limited flow of air to the combustible fuel element, thereby helping to control the temperature at which the fuel element is in short supply, thereby controlling or directing heat transfer to the aerosol generating member.

In order to reduce the combustion rate and temperature of the fuel element and thus to maintain a low CO / COa ratio, a non-porous or zero-porous paper which has been treated to be slightly porous and in the case of, for example, non-combustible mica paper with a high content of holes. Such paper controls heat generation, especially during mid-suction (i.e., suction 4-6).

From the aerosol generating portion to the mouth end, non-porous paper can be used to maximize the aerosol inlet that would otherwise be diluted by radial (i.e., exterior) air penetration through the product.

Such papers are known in the cigarette paper industry and combinations of these papers can be used to produce various effects. Preferred papers used in the products of the present invention include Ecusta 01788 and 646 coating papers manufactured by Ecusta, Pisgah Forest, North Carolina and Kimperly-Clark's KC-63-5, P 878-5, P 878-16-2 and 780- 63-5 papers.

Preferred embodiments of the invention are capable of delivering at least 0.6 mg of aerosol measured as total wet particulate matter (WTPM) during the first three puffs when performing smoking under FTC smoking conditions. (FTC smoking conditions include two-second aspirations (35 mL total volume) separated by 58 seconds of coupling.) Even more preferred embodiments of the invention are capable of delivering 1.5 mg or more of aerosol on the first three aspirations. The most preferred embodiments of the invention deliver 3 mg or more of aerosol in the first three puffs when performing smoking under FTC smoking conditions. Further, preferred embodiments of the invention produce an average of at least about 0.8 mg of total wet particulate matter per puff for at least about six puffs, preferably for at least about 10 puffs under FTC smoking conditions.

Claims (7)

78818 A cigarette-like smoking article comprising: (a) a carbonaceous fuel element (10), (b) a physically separate aerosol generating member (12) containing an aerosol generating material (38) interposed between the fuel element (10) and the mouthpiece of the article, and (c) a physically discrete tobacco-containing mass (88, 94) characterized in that the physically discrete tobacco-containing mass (88, 94) surrounds at least a portion of the aerosol-forming portion (12). Product according to Claim 1, characterized in that the aerosol-forming material (38) is enclosed in a heat-conducting container (90, 96). Product according to claim 2, characterized in that the tank (90,96) is in contact with the fuel element (10). Product according to claim 1, 2 or 3, characterized in that it further comprises a flexible insulating part (72) surrounding at least a part of said aerosol-forming part (12) and / or fuel element (10). Product according to claim 4, characterized in that the insulating part (72) is flexible and at least about 0.5 mm thick. Product according to Claim 4, characterized in that the insulating part (72) melts during use. Product according to Claim 4, characterized in that the insulating part (72) does not burn during use.