AU595483B2 - Smoking article - 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

i FORM 10 SPRUSON FERGUSON COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 595 48 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE: 4 42 4 4, 4I

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4i C 44 Class Int. Class Sct;l'h d's.co i~rin s and ~ats a1Kva UdQ Complete Specification Lodged: Accepted: Published: Priority: Related Art: 4bq3 i 33

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4 44 4 4 9, 4* 4 444t 4 44 4 Name of Applicant: Address of Applicant: R. J. REYNOLDS TOBACCO COMPANY 403 North Main Street, Winston-Salem, North Carolina 27102, United States of America Actual Inventor(s): ANDREW JACKSON SENSABAUGH, JR., HENRY THOMAS RIDINGS, JOHN HUGHES REYNOLDS IV MICHAEL DAVID SHANNON, CHANDRA KUMAR BANERJEE and ERNEST GILBERT FARRIER Address for Service: Spruson Ferguson, Patent Attorneys, Level 33 St Martins Tower, 31 Market Street, Sydney, New South Wales, 2000, Australia Complete Specification for the invention entitled: "SMOKING ARTICLE" The following statement is a full description of this invention, including the best method of performing it known to us SB!&:ep 140F SMOKING ARTICLE ABSTRACT OF THE DISCLOSURE The present invention relates to a smoking article which produces an aerosol that resembles tobacco smoke, but contains no more than a minimal amount of incomplete combustion or pyrolysis products.

Preferred embodiments of the present smoking article comprise a short combustible carbonaceous fuel element, a heat stable substrate bearing an aerosol o |9 forming substance, a heat conducting member which contacts a portion of the fuel element and the substrate, and an insulating jacket surrounding at least a portion of the fuel element.

The smoking article of the present invention ii3 capable of providing an aerosol "smoke" which is chemically simple, consisting essentially of air, oxides of carbon, water, and the aerosol which carries any desired flavorants or other desired volatile materials, and trace amounts of other materials. The r aerosol "smoke" from the preferred embodiments has no significant mutagenic activity as measured by the Ames Test. In addition, the article may be made virtually ashless so that the user does not have to remove any ash during use.

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Docket No. 35,376 FOR SMOKING ARTICLE i!BACKGROUND OF THE INVENTION The present invention relates to a smoking article which produces an aerosol that resembles tobacco smoke, and which contains no more than a minimal amount of incomplete combustion or pyrolysis products.

Many smoking articles have been proposed through the years, especially over the last 20 to 30 years, but none of these products has ever realized any commercial success.

I Despite decades of interest and effort, there is K still no smoking article on the market which provides the benefits and advantages associated with conventional cigarette smoking, without delivering considerable quantities of incomplete combustion and pyrolysis products.

SUMMARY OF THE INVENTION The present invention relates to a smoking article which is capable of producing substantial quantities of aerosol, both initially and over the useful life of Ctthe product, without significant thermal degradation C" of the aerosol former and without the presence of substantial pyrolysis or incomplete combustion

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-2products, and preferably without substantial quantities of sidestream smoke. Smoking articles in accordance with the present invention are capable of providing the user with the sensations and benefits of cigarette smoking, without burning tobacco.

These and other advantages are obtained by providing an elongated, cigarette type smoking article which utilizes a combustible fuel element, preferably of a carbonaceous material, in conjunction with a physically separate aerosol generating means which is kin conductive heat exchange relationship with the fuel element. Upon lighting, the fuel element generates 0 heat which is used to volatilize the aerosol forming 0 substance or substances in the aerosol generating 04 15 means. These volatile materials are then drawn toward 0*00 o ao tl-. mouth end, especially during puffing, and into the user's mouth, akin to the smoke of a conventional Uo ocigarette.

0044 0 Preferably, the fuel element is less than about mm in length, more preferably less than 15 mm in length, has a density of at least 0.5 g/cc, and is 0 00 provided with one or more longitudinal passages.

o Advantageously, the aerosol generating means includes 0 a heat stable substrate including one or more aerosol f 25 forming substances. Preferably, the heat exchange relationship between the fuel and the aerosol generator is achieved by providing a heat conducting member, such as a metal foil, which efficiently conducts or transfers heat from the burning fuel element to the aerosol generating means.

This heat conducting member preferably contacts the fuel element and the aerosol generating means around at least a portion of their peripheral surfaces. In addition, at least a part of the fuel element is preferably provided with a peripheral insulating member, such as a jacket of insulating fibers, the jacket being preferably resilient and at least 0.5 mm thick, which reduces radial heat loss and assists in retaining and directing heat from the fuel element toward the aerosol generating means. The insulating member preferably overwraps at least part of the fuel i element, and advantageously at least part of the aerosol generating means.

Because the preferred fuel element is relatively short, the hot, burning fire cone is always close to the aerosol generating means, which maximizes heat transfer thereto and maximizes the resultant production of aerosol, especially in embodiments which 8888 are provided with a heat conducting member. The preferred use of a relatively short, low mass substrate or carrier as the aerosol generating means, o. in close proximity to the short fuel element, also S increases aerosol production by minimizing the heat sink effect of the substrate. Because the aerosol forming substance is physically separate from the fuel element, it is exposed to substantially lower temperatures than are present in the burning fire cone, thereby minimizing the possibility of thermal 30 degradation of the aerosol former. Moreover, the especially preferred use of a carbonaceous fuel element which is substantially free of volatile organic material eliminates the pzesence of substantial pyrolysis or incomplete combustion

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-4products and eliminates the generation of substantial sidestream smoke.

smoking article of the present invention normally is provided with a mouthend piece including means, such as a longitudinal passage, for delivering the volatile material produced by the aerosol generating means to the user. Advantageously, the article has the same overall dimensions as a conventional cigarette, and as a result, the mouthend piece and the aerosol delivery means usually extend over more than half the length of the article.

Alternatively, the fuel element and the aerosol generating means may be produced without a built-in 0 mouthend piece or aerosol delivery means, for use with Z 15 a separate, disposable or reusable mouthend piece.

smoking article of the present invention also a° may include a charge or plugc of tobacco which may be o used to add a tobacco flavor to the aerosol.

o Preferably, the tobacco is placed at the mouth end of the aerosol generating means, or it may be mixed with the carrier for the aerosol forming substance.

Flavoring agents also may be incorporated into the article to flavor the aerosol delivered to the user.

Preferred embodiments of the invention are capable of delivering at least 0.6 mg of aerosol, measured as wet total particulate matter, in the first 3 puffs, when smoked under FTC smoking conditions. (FTC smoking conditions consist of two seconds of puffing ml total volume) separated by 58 seconds of smolder). More preferred embodiments of the invention are capable of delivering 1.5 mg or more of aerosol in the first 3 puffs. Most preferably, embodiments of the invention are capable of delivering 3 mg or more of aerosol in the first 3 puffs when smoked under FTC

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00 04 0 0 0 0 0 0 os o 040 0 0 0 0 0 0 006 a o o «o o 00 S0 0 0 0 0 0 0 0 I tt o ooao oo49 Osb smoking conditions. Moreover, preferred embodiments of the invention deliver an average of at least about 0.8 mg of wet total particulate matter per puff for at least about 6 puffs, preferably at least about puffs, under FTC smoking conditions.

The smoking article of the present inventionA~lso is capable of providing an aerosol which is chemically simple, consisting essentially of oxides of carbon, air, water, and the aerosol which carries any desired flavorants or other desired volatile materials, and trace amounts of other materials. The aerosol preferably has no significant mutagenic activity according to the Ames test discussed hereinafter. In addition, the article may be made virtually ashless so 15 that the user does not have to remove any ash during use.

As used herein, and only for the purposes of this application, "aerosol" is defined to include vapors, gases, particles, and the like, both visible and invisible, and especially those components perceived by the user to be "smoke-like," generated by action of the heat from the burning fuel element upon substances contained within the aerosol generating means, or elsewhere in the article. As so defined, the term 25 "aerosol" also includes volatile flavoring agents and/or pharmacologically or physiologically active agents, irrespective of whether they produce a visible aerosol.

As used herein, the phrase "conductive heat exchange relationship" is defined as a physical arrangement of the aerosol generating means and the fuel element whereby heat is transferred by conduction from the burning fuel element to the aerosol generating means substantially throughout the 0 *4 D 4O o os 4 a t tr: -6a a 0 a 0 0 0 0 00 0 0 0 cau o o So o 0 0 0 s000 0 0 0 oi Bon .ao 0 00 0 0 0t 00 0 tt 0

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9«* burning period of the fuel element. Conductive heat exchange relationships can be achieved by locating the aerosol generating means in contact with the fuel element and in close proximity to the burning portion of the fuel element, and/or by utilizing a conductive member to carry heat from the burning fuel to the aerosol generating means. Preferably both methods of providing conductive heat transfer are used.

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

As used herein, the term "insulating means" applies to all materials which act primarily as insulators. Preferably, these materials do not burn during use, but they may include slow burning carbons 15 and like materials, as well as materials which fuse during use, such as low temperature grades of glass fibers. The insulators have a thermal conductivity in g-cal/(sec) (cm 2 of less than about 0.05, preferably less than about 0.02, most preferably less 20 than about 0.005. See, Hackh's Chemical Dictionary, 34 (4th ed., 1969) and Lange's Handbok of Chemistry 10, 272-274 (llth ed., 1973).

The smoking article of the present invention is described in greater detail in the accompanying 25 drawings and in the detailed description of the invention which follow.

BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 through 9 are longitudinal views of various embodiments of the invention; Figure 1A is a sectional view of the embodiment of Figure 1, taken along lines lA-lA in Figure 1; Figure 2A is a longitudinal view of a modified, I C~ f -7tapered fuel element of the embodiment of Figure 2; Figure 3A is a sectional view of the embodiment of Figure 3, taken along liner 3A-3A in Figure 3; and Figure 10 depicts the average peak temperature profile of the smoking article of Example 5 during use.

DETAILED DESCRIPTION OF THE INVENTION The embodiment of the invention illustrated in Figure 1, which preferably has the diameter of a conventional cigarette, includes a short, combustible 9 ao carbonaceous fuel element 10, an abutting aerosol 1 generating means 12, and a foil lined paper tube 14, "which forms the mouthend piece 15 of the article. In oo this embodiment, fuel element 10 is a "blowpipe" charcoal, i.e. carbonized wood, which is provided with coo °five longitudinally extending holes 16. See Figure 6.o 1A. The fuel element 10, which is about 20 mm long, optionally may be wrapped with cigarette paper to improve lighting of the charcoal fuel. This paper may be treated with known burn additives.

Aerosol generating means 12 includes a plurality of T glass beads 20 coated with an aerosol forming substance or substances, such as glycerin. The glass beads are held in place by a porous disc 22, which may be made of cellulose acetate. This disc may be provided with a series of peripheral grooves 24 which provide passages between the disc and the foil lined tube 14.

The foil lined paper tube 14, which forms the mouthend piece of the article, surrounds aerosol generating means 12 and the rear, non-lighting end of fuel element 10. The tube also forms an aerosol delivery passage 26 between the aerosol generating -8means 12 and mouth end 15 of the article.

The presence of foil lined tube 14, which couples the nonlighting end of fuel 10 to aerosol generator 12, also increases heat transfer to the aerosol generator. The foil also helps to extinguish the fire cone. When only a small amount of the unburned fuel remains, heat loss through the foil acts as a heat sink which helps to extinguish the fire cone.

The foil used in this article is typically an aluminum foil of 0.35 mils (0.0089 mm) in thickness, but the thickness and/or the type of metal employed may be varied to achieve any desired degree of heat transfer. Other types of heat conducting members such as Grafoil, available from Union Carbide, also may be 15 employed.

0 The article illustrated in Figure 1 also includes o an optional mass or plug of tobacco 28 to contribute flavor to the aerosol. This tobacco charge 28 may be placed at the mouth end of disc 22, as shown in Figure 1, or it may be placed between glass beads 20 and disc 22. It also may be placed in passage 26 at a location spaced from aerosol generator 12.

In the embodiment shown in Figure 2, the short fuel element 10 is a pressed carbon rod or plug, about 20 mm long, which is provided with an axial hole 16.

64*Alternatively, the fuel may be formed from carbonized fibers and preferably also provided with an axial passageway corresponding to hole 16. In this embodiment, aerosol generating means 12 includes a thermally stable conductive carbonaceous substrate such as a plug of porous carbon, which is impregnated with an aerosol forming substance or substances. This substrate may be provided with an optional axial passageway 32, as is shown in Figure 2. This embodiment also includes a mass of tobacco 28 which is ji1 i 00 00 a 6 o a 0 ~00a 0) 0 000 0 a 00 0000 o D 1 aO b .0 0.0 a~ a -9preferably placed at the mouth end of substrate For appearance sake, this article also includes an optional high porosity cellulose acetate filter 34, which may be provided with peripheral grooves 36 to provide passages for the aerosol forming substance between filter 34 and foil tube 14. Optionally, as shown in Figure 2A, the lighting end 11 of the fuel element may be tapered to improve lightability.

The embodiment of the invention illustrated in Figure 3, includes a short combustible carbonaceous fuel element 10, connected to aerosol generating means 12 by a heat conductive rod 99 and by a foil lined paper tube 14, which also leads to the mouth end 15 of the article. in this embodiment, fuel element 10 may 15 be blowpipe charcoal or a pressed or extruded carbon rod or plug or other carbonaceous fuel source.

Aerosol generating means 12 includes a thermally stable carbonaceous substrate 30, such as a plug of porous carbon, which is impregnated with an aerosol forming substance or substances. This embodiment includes a void space 97 between the fuel element and the substrate 30. The portion of the foil lined tube 14 surrounding this void space includes a plurality of peripheral holes 100 which permit sufficient air to enter the void space to provide appropriate pressure drop.

As shown in Figures 3 and 3A, the heat conducting means includes a conductive rod 99 and the foil lined tube 14. The rod 99, preferably formed of aluminum, has at least one, preferably from 2 to 5, peripheral grooves 96 therein, to allow air passage through the substrate. The article of Figure 3 has the advantage that the air introduced into the void space 97 contains less carbon oxidation products because it is Is o e O o 0 a a 0 6 O0 0 00 0 0 060 600 0000 Saeo Uo not drawn through the burning fuel.

The embodiment illustrated in Figure 4 includes a fibrous carbon fuel element 10, such as carbonized cotton or rayon. The fuel element includes a single axial hole 16. The substrate 38 of the aerosol generator is a granular, thermally stable carbon. A mass of tobacco 28 is located immediately behind the substrate. This article is provided with a cellulose acetate tube 40, in place of the foil lined tube of previous embodiments. This tube 40 includes an annular section 42 of cellulose acetate tnw surrounding an optional plastic, polypropylene tube 44. At the mouth end 15 of this element there is a low efficiency cellulose acetate filter plug 15 The entire length of the article is wrapped in cigarette-type paper 46. A cork or white ink coating 48 may be used on the mouth end to simulate tipping.

A foil strip 50 is located on the inside of the paper, toward the fuel end of the article. This strip preferably excends from the rear portion of the fuel element to the mouth end of the tobacco charge 28. It may be integral with the paper or it may be a separate piece applied before the paper overwrap.

The embodiment of Figure 5 is similar to that of 25 Figure 4. In this embodiment, the aerosol generating means 12 is formed by an aluminum macrocapsule 52 which is filled with a granular substrate or, as shown in the drawing, a mixture of a granular substrate 54, and tobacco 56. The macrocapsule 52 is crimped at its ends 58, 60 to enclose the material and to inhibit migration of the aerosol former. The crimped end 58, at the fuel end, preferably abuts the rear end of the fuel element to provide for conductive heat transfer.

A void space 62 formed by end 58 also helps to inhibit Q0 6 0 000 0 0 06 00 0.

b a 0 6t t _I -11migration of the aerosol former to the fuel.

Longitudinal p.ssageways 59 and 61 are provided to permit the passage of air and the aerosol forming substance. Macrocapsule 52 and fuel element 10 may be united by a conventional cigarette paper 47, as illustrated in the drawing, by a perforated ceramic paper, or a foil strip. If cigarette paper is used, a strip 64 near the rear end of the fuel should be printed or treated with sodium silicate or other known materials which cause the paper to extinguish. The entire length of the article is overwrapped with conventional cigarette paper 46.

Figure 6 illustrates another embodiment having a pressed carbon fuel plug 10. In this embodiment, the fuel element has a tapered lighting end 11 for easier "t lighting and a tapered rear end 9 for easy fitting into a tubular foil wrapper 66. Abutting the rear end of the fuel element is an aluminum disc 68 with a 9,99 center hole 70. A second, optional aluminum disc 72 with hole 74 is located at the mouth end of the aerosol generator 12. In between is a zone 76 of a particulate substrate and a zone 78 of tobacco. The 4'9 foil wrapper 66 in which the fuel element is mounted *extends back beyond the second aluminum disc 72. This 25 embodiment also includes a hollow cellulose acetate rod 42 with an internal polypropylene tube 44, and a cellulose acetate filter plug 45. The entire length of the article is preferably wrapped with cigarette paper 46.

The embodiment shown in Fig:qire 7 illustrates the use of a substrate 80 embedded within a large cavity 82 in fuel element 10. In this embodiment, the fuel element preferably is formed from an extruded carbon, and the substrate 80 usually is a relatively rigid, -12porous material. The entire length of the article is wrapped with conventional cigarette paper 46. This embodiment may also include a foil strip 84 to couple fuel element 10 to the cellulose acetate tube 40 and to help extinguish the fuel.

The embodiments shown in Figures 8 and 9 include a nonburning insulating jacket 86 around fuel element to insulate and concentrate the heat in the fuel element. These embodiments also help to reduce any fire causing potential of the burning fire cone.

In the embodiment shown in Figure 8, both fuel l element 10 and substrate 30 are located within an annular jacket or tube 86 of insulating fibers, such \o o as ceramic glass) fibers. Nonburning carbon or 15 graphite fibers may be used in place of ceramic fibers. Fuel element 10 is preferably an extruded o op., carbon plug having a hole 16. In the illustrated embodiment, the lighting end 11 extends slightly beyond the edge of jacket 86 for ease of lighting.

Substrate 30 is a solid porous carbon material, although other types of substrates may be used. The S substrate and the rear portion of the fuel element are surrounded by a piece of aluminum foil 87. As illustrated, this jacketed fuel/substrate unit is coupled to a mouthend piece, such as the elongated cellulose acetate tube 40 shown in the drawing, with an overwrap of conventional cigarette paper 46. The jacket 86 extends to the mouth end of substrate but may replace cellulose acetate rod 42.

In the embodiment shown in Figure 9, an aluminum macrocapsule 52 of the type shown in Figure 5 is used to enclose a granular substrate 54 and tobacco 56.

This macrocapsule is preferably positioned entirely within the insulator jacket 86. In addition, the L I -13lighting end 11 of fuel element 10 does not protrude beyond the forward end of jacket 86. Preferably, the macrocapsule and the rear portion of the fuel element are surrounded by a piece of aluminum foil in a manner similar to that shown in Figure 8.

Alternatively, the aluminum foil 52 which surrounds the substrate is only crimped at the mouth end. In such an embodiment, the rear end of the fuel element may be inserted into one end of the foil and a polypropylene tube may be fitted over or placed in abutment with the mouth end of the foil. The entire DO assembly is overwrapped with fiberglass to a diameter 0 D of a conventional cigarette.

o Upon lighting any of the aforesaid embodiments, 15 the fuel element burns, generating the heat used to volatilize the aerosol forming substance or substances o o0 present in the aerosol generating means. These Svolatile materials are then drawn toward the mouthend, 000 especially during puffin, and into the user's mouth, akin to the smoke of a conventional cigarette.

Because the fuel element preferably is relatively short, the hot, burning fire cone is always close to oI: the aerosol generating body, which maximizes heat transfer to the aerosol generating means, and resultant production of aerosol, especially when the preferred heat conducting member is used. In addition, the preferred insulating member tends to confine, direct, and concentrate the heat toward the central core of the article, thereby increasing the heat transferred to the aerosol forming substance.

Because the aerosol forming substance is physically separate from the fuel element, it is exposed to substantially lower temperatures than are present in the burning fire cone. This minimizes the I I I 1_ -14possibility of thermal degradation of the aerosol former. This also results in aerosol production during puffing, but little or no aerosol production during smolder. In addition, the use of the preferred carbonaceous fuel elements and a physically separate aerosol generating means eliminates the presence of substantial pyrolysis or incomplete combustion products and avoids the production of substantial sidestream smoke.

Because of the small size and burning characteristics of the preferred carbonaceous fuel element employed in the present invention, the fuel 0 0 element usually begins burning over substantially all of its exposed length within a few puffs. Thus, the 00o0 portion of the fuel element adjacent to the aerosol 0 generating means becomes hot quickly, which significantly increases heat transfer to the aerosol generating means, especially during the early and middle puffs. Because the preferred fuel element is short, there is never a long section of nonburning 0 fuel to act as a heat sink, as was common in previous thermal aerosol articles. Heat transfer, and therefor aerosol delivery, also is enhanced by the use of holes generator, especially during puffing.

In the preferred embodiments of the invention, the short carbonaceous fuel element, heat conducting member, insulating means, and passages in the fuel cooperate with the aerosol generator to provide a system which is capable of producing substantial quantities of aerosol, on virtually every puff. The close proximity of the fire cone to the aerosol generator after a few puffs, together with the insulating means, results in high heat delivery both L_ _II I: i! during puffing and during the relatively long period of smolder between puffs.

While not wishing to be bound by theory, it is believed that the aerosol generating means is maintained at a relatively high temperature between puffs, and that the additional heat delivered during puffs, which is significantly increased by the hole or holes in the fuel element, is primarily utilized to vaporize the aerosol forming substance. This increased heat transfor makes more efficient use of the available fuel energy, reduces the amount of fuel BE o- needed, and helps deliver early aerosol. Further, the 0 0 conductive heat transfer utilized in the present Sinvention is believed to reduce the carbon fuel 000 6o00 15 combustion temperature which, it is further believed, reduces the CO/CO 2 ratio in the combustion products 00 S Sproduced by the fuel. See, G. Hagg, General Inorgani c -Chemistry, at p. 592 (John Wiley Sons, S0 1969).

Furthermore, by the appropriate selection of the fuel element, the insulating jacket, the paper o 0 overwrap, and the heat conducting means, it is 0°6«i possible to control the burn properties of the fuel 0 source. This provides opportunities for control of .o 25 heat transfer to the aerosol generator, which in turn, alters the number of puffs and/or the amount of aerosol delivered to the user.

In general, the combustible fuel elements which may be employed in practicing the invention are less than about 30 mm long. Advantageously the fuel element is about 20 mm or less, preferably about 15 mm or less in length. Advantageously, the diameter of the fuel element is between about 3 and 8 mm, preferably about 4 to 5 mm. The density of the fuel -16elements employed herein has ranged from about g/cc to about 1.5 g/cc. Preferably, the density is greater than 0.7 g/cc., more preferably greater than 0.8 g/cc. Preferably, the fuel is provided with one or more longitudinally extending holes, such as holes 11 in Figures 1 through 5. These holes provide porosity and increase early heat transfer to the substrate by increasing the amount of hot gases which reach the substrate.

The preferred fuel elements employed herein are primarily formed of a carbonaceous material.

Carbonaceous fuel elements are preferably from about 00 sa o to 15 mm, more preferably, from about 8 to 12 mm in o0 length. Carbonaceous fuel elements having these 00 o 15 characteristics are sufficient to provide fuel for at °0o o: least about 7 to 10 puffs, the normal number of puffs generally obtained by smoking a conventional cigarette 0 o 0 °"°under FTC conditions.

Preferably, the carbon content of such a fuel element is at least 60 70%, most preferably at least about 80% or more by weight. Excellent results have been achieved with fuel elements having a carbon e0 0 0content of above above about 85% by weight. High Scarbon content fuels are preferred because they produce minimal pyrolysis and incomplete combustion products, little or no visible sidestream smoke, and minimal ash and have high heat capacity. However, lower carbon content fuel elements, about 50 weight percent, are within the scope of this invention, especially where a nonburning inert filler is used.

Also, while not preferred, other fuel materials may be employed, such as tobacco, tobacco substitutes and the like, provided that they they generate and -17conduct sufficient heat to the aerosol generating means to produce the desired level of aerosol from the aerosol forming material, as discussed above. The density of the fuel used should be above about 0.5g/cc., preferably above about 0.7 g/cc., which is higher than the densities normally used in conventional smoking articles. Where such other materials are used, it is much preferred to include carbon in the fuel, preferably in amounts of at least about 20 40% by weight, more preferably at least about 50% by weight, and most preferably at least about 65 -70% by weight, the balance being being the 0" o other fuel components, including any binder, burn modifiers, moisture, etc.

00 15 The carbonaceous materials used in or as the preferred fuel may be derived from virtually any of 00 the numerous carbon sources known to those skilled in So o the art. Preferably, the carbonaceous material is 0 obtained by the pyrolysis or carbonization of cellulosic materials, such as wood, cotton, rayon, tobacco, coconut, paper, and the like, although carbonaceous materials from other sources may be used.

0 0 0 0 .°00 In most instances, the carbonaceous fuel element "l .should be capable of being ignited by a conventio'ial cigarette lighter without the use of an oxidizing agent. Burning characteristics of this type may generally be obtained from a cellulosic material which has been pyrolyzed at temperatures between about 400°C to about 10000C, preferably between about 500OC to about 9500C, in an inert atmosphere or under a vacuum. The pyrolysis time is not believed to be critical, as long as the temperature at the center of the pyrolyzed mass has reached the aforesaid temperature range for at least a few minutes.

However, a slow pyrolysis, employing gradually 1_1 -18increasing temperatures over several hours is believed to produce a more uniform material with a higher carbon yield.

While undesirable in most cases, carbonaceous fuel elements which require the addition of an oxidizing agent to render them ignitable by a cigarette lighter are within the scope of this invention, as are carbonaceous materials which require the use of a glow retardant or other type of combustion modifying agent.

Such combustion modifying agents are disclosed in many patents and publications and are known to those of ordinary skill in the art.

oo The most preferred carbonaceous fuel elements used o in practicing the invention are substantially free of 00 15 volatile organic material. By that, it is meant that 0o0o the fuel element is not purposely impregnated or mixed a 0 with substantial amounts of volatile organic materials, 00 o o such as volatile aerosol forming or flavoring agents, 0o*0 which could degrade in the burning fuel. However, ooY 20 small amounts of water, which are naturally adsorbed by the fuel, may be present therein. Similarly, small amounts of aerosol forming substances may migrate from j, the aerosol generating means and thus may also be present in the fuel element.

A preferred carbonaceous fuel element is a pressed or extruded carbon mass prepared from carbon and a binder, by conventional pressure forming or extrusion techniques. A preferred activated carbon for such a fuel element is PCB-G, and a preferred non-activated carbon is PXC, both available from Calgon Carbon Corporation, Pittsburgh, PA. Other preferred carbons for pressure forming and/or extrusion are prepared from pyrolyzed cotton or pyrolyzed papers.

The binders which may be used in preparing such a fuel element are well known in the art. A preferred I, ~I -19binder is sodium carboxymethylcellulose (SCMC), which may 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 gums, such as guar gum, and other cellulose derivatives, such as methylcellulose and carboxymethylcellulose (CMC).

A wide range of binder concentrations can be utilized. Preferably, the amount of binder is limited to minimize contribution of the binder to undesirable combustion products. On the other hand, sufficient binder must be included to hold the fuel element Z together during manufacture and use. The amount used 0 0 will thus depend on the cohesiveness of the carbon in s 15 the fuel element.

SIf desired, the aforesaid fuel elements may be 0 pyrolyzed after formation, for example, to about 650 0 C for two hours, to convert the binder to carbon ouo thereby forming a virtually 100% carbon fuel element.

The fuel elements employed in the present invention also may contain one or more additives to improve o e burning, such as up to about 5 weight percent sodium ,0 °chloride to improve smoldering characteristics and as a S" glow retardant. Also, up to about 5, preferably 1 to s t 25 2, weight percent of potassium carbonate may be included to improve lightability. Additives to improve physical characteristics, such as clays like kaolins, serpentines, attapulgites, and the like also may be used.

Another carbonaceous fuel element is a carbon fiber fuel, which may be prepared by carbonizing a fibrous precursor, such as cotton, rayon, paper, polyacrylonitile, and the like. Generally, pyrolysis at from about 650 0 C to 10000, preferably at about 9500, for about 30 minutes, in an inert atmosphere or vacuum, is sufficient to produce a suitable carbon fiber with good burning characteristics. Combustion modifying additives also may be added to these fibrous fuels.

The aerosol generating means used in practicing the invention is physically separate from the fuel element. By physically separate it is meant that the substrate, container or chamber which contains the aerosol forming materials is not mixed with, or a part of, the burning fuel element. As noted previously, this arrangement helps reduce or eliminate thermal degradation of the aerosol forming substance and the :o presence of sidestream smoke. While not a part of the 15 fuel, the aerosol generating means is in a conductive S0 heat exchange relationship with the fuel element, and :preferably abuts or is adjacent to the fuel element.

Preferably, the aerosol generating means includes 0 -one or more thermally stable materials which carry one or more aerosol forming substances. As used herein, a thermally stable material is one capable of withstanding the high temperatures, 400 0 C S600 0 C, which exist near the fuel without #0 0 0 decomposition or burning. The use of such material is o' 25 believed to help maintain the simple "smoke" chemistry of the aerosol, as evidenced by the lack of Ames activity in the preferred embodiments. While not Spreferred, other aerosol generating means, such as heat l+ rupturable microcapsules, or solid aerosol forming substances, are within the scope of the invention, provided they are capable of releasing sufficient aerosol forming vapors to satisfactorily resemble tobacco smoke.

Thermally stable materials which may be used as a -21substrate or carrier for the aerosol forming substance are well known to those skilled in the art. Useful substrates should be porous and must be capable of retaining an aerosol forming compound when not in use and capable of releasing a potential aerosol forming vapor upon heating by the fuel element.

Useful thermally stable materials include thermally stable adsorbent carbons, such as porous grade carbons, graphite, activated, or nonactivated carbons, and the like. Other suitable materials include inorganic solids such as ceramics, glass, alumina, vermiculite, clays such as bentonite, and the like. The currently t' preferred substrate materials are carbon felts, o fibers, and mats, activated carbons, and porous carbons L m 15 such as PC-25 and PG-60 available from Union Carbide, o"oo as well as SGL carbon available from Calgon.

"Depending upon the particular aerosol generating means employed herein, the composition and configuration thereof may generally be selected from particulate, fibrous, porous blocks, solid blocks with one or more axially extending passageways therethrough, and the like. Substrates, especially particulates, may Sbe placed within a container, preferably formed from a metallic foil.

The aerosol generating means used in the invention 0 is usually located no more than about 60 mm, preferably no more than 30 mm, most preferably no more than 15 mm •from the lighting end of the fuel element. The aerosol generator may vary in length from about 2 mm to about S 60 mm, preferably from about 5 mm to 40 mm, and most preferably from about 20 mm to 35 mm. If a non-particulate substrate is used, it may be provided with one or more holes, to increase the surface area of the substrate, and to increase air flow and heat -22transfer.

The aerosol forming substance or substances used in the invention must be capable of forming an aerosol at the temperatures present in the aerosol generating means when heated by the burning fuel element. Such substances preferably will be composed of carbon, hydrogen and oxygen, but they may include other materials. The aerosol forming substances can be in Ssolid, semisolid, or liquid form. The boiling point of the substance and/or the mixture of substances can range up to about 500 0 C. Substances having these characteristics include polyhydric alcohols, such as glycerin and propylene glycol, as well as aliphatic o °esters of mono-, di-, or poly-carboxylic acids, such as 15 methyl stearate, dodecandioate, dimethyl tetradodecandioate, and others.

4 o Preferably, the aerosol forming substances will I o o include a mixture of a high boiling, low vapor pressure I substance and a low boiling, high vapor pressure substance. Thus, on early puffs, the low boiling substance will provide most of the initial aerosol, while, when the temperature in the aerosol generator increases, the high boiling substance will provide most S of the aerosol.

oo 25 The preferred aerosol forming substances are polyhydric alcohols, or mixtures of polyhydric alcohols. Especially preferred aerosol formers are selected from glycerin, propylene glycol, triethylene Sglycol, or mixtures thereof.

The aerosol forming substance may be dispersed on or within the aerosol generating means in a concentration sufficient to permeate or coat the substrate, carrier, or container. For example, the aerosol forming substance may be applied full strength

I

-23or in a dilute solution by dipping, spraying, vapor deposition, or similar techniques. Solid aerosol forming components may be admixed with the substrate and distributed evenly throughout prior to formation.

While the loading of the 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 may generally vary from about 20 mg to about 120 mg, preferably from about 35 mg to about 85 mg, and most preferably from about 45 mg to about 65 mg. As much as o possible of the aerosol former carried on the aerosol generating means should be delivered to the user as WTPM. Preferably, above about 2 weight percent, more 15 preferably above about 15 weight percent, and most preferably above about 20 weight percent of the aerosol former carried on the aerosol generating means is *o delivered to the user as WTPM.

The aerosol generating means also may include one or more volatile flavoring agents, such as menthol, vanillin, artificial coffee, tobacco extracts, o °@°onicotine, caffeine, liquors, and other agents which *o o impart flavor to the aerosol. It also may include any o other desirable volatile solid or liquid materials.

25 As previously pointed out, the smoking article of the present invention also may include a charge or plug of tobacco which may be used to add a tobacco flavor to the aerosol. Preferably, the tobacco is placed at the mouth end of the aerosol generating means, or it may be mixed with the carrier for the aerosol forming substance. Flavoring agents also may be incorporated into the article to flavor the aerosol delivered to the user.

If a charge of tobacco is employed, hot vapors are -24swept through the bed of tobacco to extract and vaporize the volatile components in the tobacco, without the need for tobacco combustion. Thus the user of this smoking article receives an aerosol which contains the qualities and flavors of natural tobacco without the combustion products produced by a conventional cigarette.

Alternatively, these optional agents may be placed between the aerosol generating means and the mouthend, such as in a separate substrate or chamber in the passage which leads from the aerosol generating means i° to the mouthend, or in the optional tobacco charge. If o desired, these volatile agents may be used in lieu of 0* part, or all, of the aerosol forming substance, so that 15 the article delivers a nonaerosol flavor or other material to the user.

Articles of the type disclosed herein may be used o0Q or may be modified for use as drug delivery articles, for delivery of volatile pharmacologically or physiologically active materials such as ephedrine, metaproterenol, terbutaline or the like.

The heat conducting member preferably employed in practicing this invention is typically a metallic foil, such as aluminum foil, varying in thickness from less than about 0.01 mm to about 0.1 mm, or more. The thickness and/or the type of conducting material may be varied to achieve virtually any desired degree of heat transfer. As shown in the illustrated embodiments, the heat conducting member preferably contacts or overlaps a portion of the fuel element and the aerosol generating means, and may form the container which encloses the aerosol forming substance.

Insulating members which may be used in accordance with the present invention generally comprise inorganic a or organic fibers such as those made out of glass, alumina, silica, vitreous materials, mineral wool, carbons, silicons, boron, organic polymers, cellulosics, and the like; including mixtures of these materials. Nonfibrous insulating materials, such as silica aerogel, pearlite, glass, and the like, formed in mats, strips or other shapes, may also be used.

Preferred insulating members are resilient; to help simulate the feel of a conventional cigarette. These materials act primarily as an insulating jacket, retaining and directing a significant portion of the heat formed by the burning fuel element to the aerosol generating means. Because the insulating jacket 0*e becomes hot adjacent to the burning fuel element, to a 15 limited extent, it also may conduct heat toward the aerosol generating means.

Sooo Currently preferred insulating materials include 0, ceramic fibers, such as glass fibers. Two especially preferred glass fibers are available from the Manning Paper Company of Troy, New York, under the designations, Manniglas 1000 and Manniglas 1200.

Generally the insulating fiber is wrapped over at least a portion of the fuel element and any other desired Sportion of the article, to a final diameter of from about 7 to 8 mm. Thus, the preferred thickness of the insulating layer is from about 0.5 mm to 2.5 mm, preferably, from about 1 mm to 2 mm. When possible, glass fiber materials having a low softening point, below about 650 0 C, are preferred.

When the insulating means is fibrous, there is preferably employed a barrier means at the mouth end of the article. One such barrier means comprises an annular member of high density cellulose acetate tow which abutts the fibrous insulating means and which is a: I -26sealed, preferably at the mouth end, with, for example, glue, to block air flow through the tow.

In most embodiments of the invention, the fuel/aerosol generating means combination will be attached to a mouthend piece, such as a foil lined paper or cellulose acetate/plastic tubes illustrated in the figures, although a mouthend piece may be provided separately, in the form of a cigarette holder.

This element of the article provides the passageway which channels the vaporized aerosol forming substance into the mouth of the user. Due to its length, o preferably about 50 to 60 mm or more, it also keeps the o a °hot fire cone away from the mouth and fingers of the aooo user.

ao 0 15 Suitable mouthend pieces should be inert with respect to the aerosol forming substances, should have BSo a water or liquid proof inner layer, should offer ace minimum aerosol loss by condensation or filtration, and &ooo should be capable of withstanding the temperature at the interface with the other elements of the article.

Preferred mouthend pieces include the foil lined tube 0 0 of Figures 1 3 and the cellulose-acetate tube o::o employed in the embodiments of Figures 4 9. Other suitable mouthend pieces will be apparent to those of 0" 25 ordinary skill in the art.

The mouthend pieces of the invention may include an optional "filter" tip, which is used to give the article the appearance of the conventional filtered 0 cigarette. Such filters include low density cellulose acetate filters and hollow or baffled plastic filters, such as those made of polypropylene. In addition, the entire length of article or any portion thereof may be overwrapped with cigarette paper.

The aerosol produced by the preferred articles of i -27the present invention is chemically simple, consisting essentially of air, oxides of carbon, the aerosol which carries any desired flavorants or other desired volatile materials, water, and trace amounts of other materials. The wet total particulate matter (WTPM) produced by the preferred articles of this invention has no mutagenic activity as measured by the Ames test, there is no significant dose response relationship between the WTPM of the present invention and the number of revertants occurring in standard test microorganisms exposed to such products. According to o the proponents of the Ames test, a significant dose R, dependent response indicates the presence of mutagenic CsB> materials in the products tested. See Ames et al., o"'4 15 Mut. Res., 31:347-364 (1975); Nagas et al., Mut.

Res., 42:335 (1977) A further benefit from the preferred embodiments of S.tn the present invention is the relative lack of ash produced during use in comparison to ash from a conventional cigarette. As the preferred carbon fuel source is burned, it is essentially converted to oxides o of carbon, with relatively little ash generation, and thus there is no need to dispose of ashes while using the article.

o 25 The smoking article of the present invention will be further illustrated with reference to the following examples which aid in the understanding of the present invention, but which are not to be construed as Slimitations thereof. All percentages reported herein, unless otherwise specified, are percent by weight. All temperatures are expressed in degrees Celsius and are uncorrected. In all instances, the smoking articles have a diameter of about 7 to 8 mm, the diameter of a conventional cigarette.

-28- Example 1 A smoking article was constructed in accordance with the embodiment of Figure 1. The fuel element was a 25 mm long piece of blow pipe charcoal, with five 0.040 in. (1.02 mm) longitudinal passageways made with a number 60 drill bit. The charcoal weighed 0.375 g. The fuel element was wrapped with conventional treated cigarette paper. The substrate was 500 mg of glass beads (0.64 in. [1.63 mm] average diameter) 10 having two drops, approximately 50 mg, of glycerol o coated on their surface. When packed into the tube, this substrate was about 6.5 mm long. The foil lined tube consisted of a 0.35 mil (0.0089 mm) layer of S aluminum foil inside a 4.25 mil (0.108 mm) layer of white spirally wound paper. This tube surrounded the *o*o rear 5 mm of the fuel element. A short (8 mm) piece of cellulose acetate with four grooves around the periphery was used to hold the glass beads against the 0 fuel source. An additional grooved cellulose acetate a.0 20 filter piece of 8 mm length was inserted into the mouth end of the tube to give the appearance of a conventional cigarette. The overall length of the article was about 70 mm.

Models of this type delivered considerable aerosol on the lighting puff, reduced amounts of aerosol on S, puffs 2 and 3, and good delivery of aerosol on puffs 4 through 9. Models of this type generally yielded about 5-7 mg of wet total particulate matter (WTPM) when machine smoked under FTC smoking procedures of a 35 ml puff volume, a two second puff duration, and a second puff frequency.

-29- Example 2 A. Four smoking articles were constructed with mm long pressed carbon fuel elements and glass bead substrates. The fuel elements were formed from PCB-G and 10% SCMC, at about 5000 pounds (2273 kg) of applied load with the tapered lighting end illustrated in Figure 2A. A single 0.040 in (1.02 mm) hole was formed down the center of each element. Three of the four fuel sources were wrapped with 8 mm wide strips of conventional cigarette paper. The fuel elements were inserted about 2 mm into 70 mm long sections of the o o foil lined tube described in Example 1. Glass beads, ^o coated with the amount of glycerol indicated in the oo" following table, were inserted into the open end of the foil lined tube and were held against the fuel element by 5 mm long foamed polypropylene filters having a series of longitudinally extending peripheral grooves. A 5 mm long low efficiency cellulose acetate filter piece was inserted into the mouth end of each o 20 article. These articles were machine smoked under FTC oO smoking conditions and the wet total particulate matter 6(WTPM) was collected on a series of Cambridge pads.

The results of these experiments are reported in Table

I.

e TABLE I WTPM (mg)/Puffs 1-3 4-6 7-9 10-12 Glass Beads (wt) Aerosol Former (wt) 40.5 mg 59.4 mg 60.6 mg 81.0 mg 0 00 o 0 o a o o 0 0 c 6000 .a o S0 0 0 a o o 4 0 0 00 0 0 I

A

B*

C

D

400.4 mg 405.6 mg 404.0 mg 803.8 mg 8.1 10.2 7.6 5.9 4.5 1.9 6.9 2.5 0.9 0.7 0.4 3.7 0 0 0 0.9 13.5 12.8 14.9 13.0 *The fuel rod in this model was not wrapped with 10 cigarette paper.

B. Three smoking described in Example 2A long blowpipe charcoal described in Example 1.

15 smoked under FTC smokinc collected on a series of of these tests are reported articles similar to those were constructed with 20 mm fuel elements of the type These articles were machine conditions, and the WTPM was Cambridge pads. The results in Table II.

i -31- TABLE II Glass Aerosol WTPM (mg)/Puffs Beads Former (wt) 1-3 4-6 7-9 10-12 Total E 402.4 mg 60.6 mg 0.1 5.4 6.2 0.6 12.3 F* 404.7 mg 63.1 mg 0.5 0.9 2.2 3.1 S' G 500.0 mg 50.0 mg 0.3 2.9 3.0 0 6.2 I *The fuel rod in this model was not wrapped with cigarette paper.

Q 0 sco1 10 Example 3 A. Four smoking articles were constructed as shown in Figure 2 with a 10 mm pressed carbon fuel element having the tapered lighting end illustrated in Figure 2A. The fuel element was made from 90% PCB-G carbon and 10% SCMC, at about 5000 pounds (2273 kg) of applied load. A 0.040 in. (1.02 mm) hole was drilled Sdown the center of the element. The substrate for the aerosol former was cut and machined to shape from PC-25, a porous carbon sold by Union Carbide I 20 Corporation, Danbury, CT. The substrate in each article was about 2.5 mm long, and about 8 mm in diameter. It was loaded with an average of about 27 mg of a 1:1 propylene glycol-glycerol mixture. The foil lined tube mouthend piece, of the same type as used in Example 1, enclosed the rear 2 mm of the fuel I T -32element and the substrate. A plug of Burley tobacco, about 100 mg was placed against the mouth end of the substrate. A short, about 5-9 mm, baffled polypropylene filter piece was placed in the mouth end of the foil lined tube. A 32 mm length of a cellulose acetate filter with a hollow polypropylene tube in the core was placed between the tobacco and the filter piece. The overall length of each article was about 78 mm.

B. Six additional articles were constructed Ssubstantially as in Example 3A, but the substrate length was increased to 5 mm, and a 0.040 in (1.02 mm) hole was drilled through the substrate. In addition, these articles did not have a cellulose acetate/polypropylene tube. About 42 mg of the propylene glycol-glycerol mixture was applied to the substrate. In addition, two plugs of Burley tobacco, about 100-150 mg each, were used. The first was placed against the mouth end of the substrate, and the second one was placed against the filter piece.

C. Four additional articles were constructed I substantially as in Example 3A, except that an approximately 100 mg plug of flue-cured tobacco j ^containing about six percent by weight of diammonium Burley tobacco.

D. The smoking articles from Examples 3A-C were tested using the standard Ames Test. See Ames, et al., Mut. Res., 31:347-364 (1975), as modified by Nagas e al., Mut. Res., 42:335 (1977), and 113:173-215 (1983). The samples 3A and C were "smoked" on a conventional cigarette smoking machine using the conditions of a 35 ml puff volume, a two second puff duration, and a 30 second puff frequency,

I

45 8. The article of claim 1, 3, 4 or 5, wherein the fuel element is i Y -33for ten puffs. The smoking articles of Example 3B were smoked in the same manner except that a 60 second puff frequency was used. Only one filter pad was used for each group of articles. This afforded the following wet total particulate matter (WTPM) for the indicated groups of articles:

WTPM

o o 0 0 o 0 0 o

RO

0 0 0 8 0 o o o o 0 8488 oe 8 00 8 80 B 8b 0 0 4 8 a o a a ar oa e 0 84 *4 I 1 4 I t, I: Example 3A Example 3B Example 3C 63.4 mg 50.6 mg 69.2 mg The filter pad for each of the above examples containing the collected WTPM was shaken for minutes in DMSO to dissolve the WTPM. Each sample was then diluted to a concentration of 1 mg/ml and used 15 "as is" in the Ames assay. Using the procedure of Nagas et al., kMat. es. 42:335-342 (1977), 1 mg/ml concentrations of WTPM were admixed with the S-9 activating system, plus the standard Ames bacterial cells, and incubated at 37 0 C for twenty minutes.

20 The bacterial strain used in this Ames assay was Salmonella typhimurium, TA 98. See Purchase £t Al., Nature, 264:624-627 (1976). Agar was then added to the mixture, and plates were prepared. The agar plates were incubated for two days at 37 0 C, and the 25 resulting cultures were counted. Four plates were run for each dilution and the standard deviations of the colonies were compared against a pure DMSO control culture. As shown in Table III, there was no mutagenic activity caused by any of the smoking articles ascertained by comparison of the WTPM obtained from tested. This can be the mean number of -34revertants per plate with the mean number of revertants obtained from the control (0 ug WTPM/Plate) For mutagenic samples, the mean number of revertants per plate will increase with increasing doses.

@0 a 0 0 0 0 44 tO 0 o o .3040 .3 00 o o a 00 04 00 .3 00 .3 0 0444 0 0440 o .34 0 *3 0 @0 .3.3 .3 o .31 .3 'tat 4.3 f

I

TABLE III Example 3A Dose (tic WTPM/Pl at-t) Mean Reyertants;/Plate Control 0 33 66 99 132 165 198 49.3 .1 .3 50.5 50.8 51.5 53.8 48.3 3.4 9.1 5.2 5.3 10.1 4.6 00 04 0 0 0 0 00 00 0 0004 0000 0 00 0 40 0 0 0 00 0 0440 0044 0040 Example 3B Dose hic WTPM/Plate) Meg~ Revertants/Plate Control 0 31.5 63 94.5 126 157.5 189 48.3 54.0 39 42.5 10.5 7.8 6.3 8.4 4.7 9.3 9.1 0 00 0 0 0 000 0 00 1 0 Of 0004 O 1 0* Example 3C Dose (ua WTPM/Plate) Mean Revertants/Plate Control 0 36 72 108 144 180 216 48.3 50.3 49.0 55.3 43.0 42.3 44.3 5.7 9.9 3.9 6.4 8.8 7.8 *Standard Deviation -36- Example 4 Five smoking articles were constructed as shown in Figure 2. Each article had a 10 mm pressed carbon fuel source as described in Example 3A. This fuel element was inserted 3 mm into one end of a 70 mm long aluminum foil lined tube of the type described in Example 1. A 5 mm long carbon felt substrate, cut from rayon carbon felt sold by Fiber Materials, Inc., was butted against the fuel source. This substrate S 10 was loaded with an average of about 97 mg of a 1:1 Smixture of glycerin and propylene glycol, about 3 mg o of nicotine, and about 0.1 mg of a mixture of e flavorants. A 5 mm long section of blended tobacco was butted against the mouth end of the substrate. A 15 5 mm long cellulose acetate filter piece was placed in the mouth end of the foil lined tube.

ol These articles were machine smoked under the FTC conditions. The aerosol from these articles was collected on a single Cambridge pad (133.3 mg WTPM), 20 diluted in DMSO to a final concentration of 1 mg WTPM I L per ml and tested for Ames activity as described in Example 3D using each of the following strains: ."Salmonella typhimurium TA 1535, 1537, 1538, 98, and 100. As shown in Table IV there was no mutagenic activity caused by the WTPM collected from the articles tested.

-37- TABLE TV TA 1535 M4ean Revertants TA 1537 Mean Revertants 0* Oi 0 0 o 0 0 0 00 00 0 04~94 0 00 0 00 04 o 0 0 00 0 0000 0 00 0 ~,000 Control 0 25 100 125 150

TA

Control 0 25 15 100 125 150 20 Control 0 25 50 75 100 125 150 14 13 14 11 L538 g e a R etnt TA 98 MIean- Revertants9 Control 0 100 125 150 0 04 0 4 000 0 f~ 00 00 4 0 00 4* 000 4* 04 00 4 TA 100 Mean Revertants Control 0 25 75 100 125 150 110 109 105 99 107 108 109

I

*ug WTPM/Plate -38- Example

I

o 4r o o l*4 *4 4

I.'I

4r A smoking article was built as shown in Figure 2 with a 10 mm pressed carbon fuel plug having the configuration shown in Figure 2A, but with no tobacco. The fuel element was made from a mixture of PCB-G activated carbon and 10% SCMC as a binder at about 5000 pounds (2273 kg) of applied load. The fuel element was provided with a 0.040 in (1.02 mm) longitudinal passageway. The substrate was a 10 mm 10 long porous carbon plug made from Union Carbide's It was provided with a 0.029 in. (0.74 mm) drilled axial hole, and was loaded with 40 mg of a mixture of propylene glycol and glycerol. The foil lined tube, as in Example 1, encircled the rear 2 15 mm of the fuel element and formed the mouthend piece.

The article did not have a filter tip, but was overwrapped with conventional cigarette paper. The total length of the article was 80 mm.

The average peak te.nperatures for this article are shown for both "puff" and "smolder" in Figure 10. As shown, the temperature declines steadily between the rear end of the fuel element and mouthend. This assures the user of no unpleasant burning sensation when using a product of this invention.

Example 6 A smoking article was constructed in accordance with the embodiment of Figure 3. The fuel element was a 19 mm long piece of blowpipe charcoal, with no longitudinal passageways. Embedded 15 mm into the fuel element was a 1/8 in. (3.2 mm) diameter aluminum

_A

-39rod, 28 mm in length. Four 9 mm x 0.025 in. (0.64 mm) peripheral grooves, spaced 900 apart were cut into the portion of the aluminum rod which pierced the substrate. The substrate was Union Carbide carbon 8 mm in length. The grooves in the aluminum rod extended about 0.5 mm beyond the end of the substrate toward the fuel. The substrate was loaded with 150 mg of glycerol. The foil lined tube, which was the same as in Example 1, enclosed a portion of the rear of the fuel element. A gap was left between the non-burning end of the fuel element and the substrate. A series of holes were cut through the 'o foil lined tube in this gap region to allow for air flow. A similar smoking article was constructed with Q0 15 a pressed carbon fuel plug.

0D00 I Example 7 0 A smoking article was constructed as shown in 3 *Figure 4 with a fuel source of carbonized cotton fiber. Fou. slivers of cotton were tightly braided together with cotton string to form a rope with a l diameter of about 0.4 in, (10.2 mm). This material l K was placed in a nitrogen atmosphere furnace which was heated to 9500°C. It took about 1 1/2 hours to reach that temperature, which was then held for 1/2 hour. A 16 mm piece was cut from this pyrolyzed material to be used as the fuel element. A 2 mm axial hole 16 was made through the element with a probe.

The fuel element was inserted 2 mm into a 20 mm long foil lined tube of the type described in Example 1.

100 mg of Union Carbide PC-25, in granular form, containing 60 mg of a 1:1 propylene glycol-glycerol mixture, was inserted into the foil lined tube. A long plug of tobacco, about 60 mg, was located immediately behind the granular substrate in the foil lined tube. A 48 mm long annular cellulose acetate tube with an internal 4.5 mm I.D. polypropylene tube was inserted about 3 mm into the foil lined tube. A second foil lined tube, 50 mm in length, was inserted over the cellulose acetate tube until it abutted against the 20 mm foil lined tube. A 5 mm long cellulose acetate filter plug was inserted into the end of this second foil lined tube. The overall length was 84 mm. When lit, this article produced substantial amounts of aerosol throughout the first "o six puffs with a tobacco flavor.

o 0 0o o Example 8 *0*0 o 0 0 00 15 A smoking article was constructed as shown in 0 0 0 0 o a Figure 5 with a 15 mm long fibrous fuel element 0. substantially as described in Example 7. The 0 0000 macrocapsule 52 was formed from a 15 mm long piece of 4 mil (0.10 mm) thick aluminum foil, which was crimped to form a 12 mm long capsule. This macrocapsule was loosely filled with 100 mg of granulated PC-60, a carbon obtained from Union Carbide, and 50 mg of blended tobacco. The granular carbon was impregnated with 60 mg of a 1:1 mixture of propylene glycol and glycerol. The macrocapsule, the fuel element, and the O mouthend piece were united by an 85 mm long piece of conventional cigarette paper.

Example 9 A smoking article was constructed in accordance with the embodiment of Figure 6 with a 7 mm long -41pressed carbon fuel element containing 90% PXC carbon and 10% SCMC. The longitudinal passageway was 0.040 in. (1.02 mm) in diameter. This fuel plug was inserted into a 17 mm long aluminum foil lined tube so that 3 mm of the fuel element was inside the tube. An 8 mm diameter disc of 3.5 mil (0.089 mm) aluminum foil, with a 0.049 in. (1.24 mm) diameter center hole, was inserted into the other end of the tube and butted against the end of the fuel source.

Union Carbide PG-60 carbon was granulated and sieved to a particle size of -6 to +10 mesh. 80 mg of this material was used as the substrate, and 80 mg of a 1:1 mixture of glycerin and propylene glycol was loaded on this substrate. The impregnated granules were inserted into the foil tube and rested against the foil disk on the end of the fuel source. 50 mg of blended tobacco was loosely placed against the subst:ate granules. An additional foil disk with a rrr 0.049 in. (1.24 mm) central hole was inserted into 20 the foil tube on the mouth end of the tobacco. A long hollow cellulose acetate rod with a hollow polypropylene tube as described in Example 7 was Sinserted 3 mm into the foil lined tube. A second foil 4 lined tube was inserted over the cellulose acetate rod against the end of the 17 mm foil lined tube.

tit, 'his model delivered 11.0 mg of aerosol in the first three puffs when "smoked" under FTC conditions.

Total aerosol delivery for nine puffs was 24.9 mg.

Example A smoking article having the fuel element and substrate configuration of Figure 7 was made using a mm long annular pressed carbon fuel element with an -42i inner diameter of about 4 mm and an outer diameter of about 8 mm. The fuel was made from 90% PCB-G activated carbon and 10% SCMC. The substrate was a mm long piece formed of Union Carbide PC-25 carbon with an external diameter of about 4 mm. The substrate, loaded with 55 mg of a 1:1 glycerin/propylene glycol mixture, was inserted within the end of the fuel closer to the mouth end of the article. This fuel/substrate combination was inserted 7 mm into a 70 mm foil lined tube which had a short cellulose acetate filter at the mouthend. The length of the article was about 77 mm.

The article delivered substantial amounts of aerosol on the first three puffs, and over the useful life of the fuel element.

SExample 11 tt a ieA modified version of the smoking article of Figure 9 was made as follows: A 9.5 mm long carbon fuel source with a 4.5 mm diameter and a 1 mm diameter longitudinal passageway was extruded from a mixture of 10% SCMC, 5% potassium carbonate, and 85% carbonized paper mixed with 10% water. The mixture had a dough-like consistency and was fed into an extruder.

S The extruded material was cut to length after drying at 80OC overnight. The macrocapsule was made from a 22 mm long piece of 0.0089 mm thick aluminum formed Sinto a cylinder of 4.5 mm I.D. The macrocapsule was -t Sfilled with 70 mg of vermiculite containing 50 mg of a 1:1 mixture of propylene glycol and glycerin, and 30 mg of burley tobacco to which 6% glycerin and 6% propylene glycol had been added. The fuel source and macrocapsule were joined by inserting the fuel -i T l -43source about 2 mm into the end of the macrocapsule. A mm long polypropylene tube of 4.5 mm I.D. was inserted in the other end of the macrocapsule. The fuel source, macrocapsule and polypropylene tube were thus joined to form a 65 mm long, 4.5 mm diameter segment. This segment was wrapped with several layers of Manniglas 1000 from Manning Paper Company until a circumference of 24.7 mm was reached. The unit was then combined with a 5 mm long cellulose acetate filter and wrapped with cigarette paper. When smoked under FTC conditions, the article delivered 8 mg of WTPM over the initial three puffs; 7 mg WTPM over a o puffs 4-6; and 5 mg WTPM over puffs 7-9. Total aerosol delivery over the 9 puffs was 20 mg. When t 15 placed horizontally on a piece of tissue paper, the article did not ignite or even scorch the tissue paper.

s o 0 i i 1

Claims (37)

1. An elongated cigarette-type smoking article comprising: a combustible fuel element at a lighting end of the smoking article; a physically separate aerosol generating means including an aerosol forming material, the aerosol generating means being longitudinally disposed behind the fuel element; and a heat conducting member designed and arranged to transfer heat from the fuel element to the aerosol generating means substantially throughout the time of the burning of the fuel element.

2. The article of claim 1, wherein the fuel element is less than about 30 mm in length.

3. A cigarette-type smoking article comprising a fuel element for generating heat used to volatilize an aerosol forming material during puffing throughout smoking, and a physically separate aerosol generating S means including the ae.osol forming material, the aerosol generating means o, being arranged to receive heat from ne fuel element, the fuel element a0 I 0 having a density of at least 0.5 g/cc and being less than 30 mm in length prior to smoking, the fuel element b'2ing adjacent to the aerosol generating 00a0 oo- means.

4. A cigarette-type smoking article comprising: a fuel element; e am physically separate aerosol generating means arranged to receive ,heatfrom tRe fuel element, the aerosol generating means including at least one aerosol forming material; the fuel element is adjacent to tho aerosol generating means; F a resilient insulating member, surrounding at least a portion of the S:g''I fuel element and comprising inorganic fibers and being at least 0.5 mm thick; and tct a paper overwrap for the insulating member. The article of claim 4, wherein the fuel element and the aerosol generating means are In a conductive heat exchange relationship.

6. The article of claim 4 or 5, wherein the fuel element is less than 30 mm in length.

7. The article of claim 1, 2, 3 or 4 which produces wet total particulate matter having no mutagenic activity, as measured by the Ames test. TMR/332t i il 'I 'i 45

8. The article of claim 1, 3, 4 or 5, wherein the fuel element is less than 15 mm in length.

9. The article of claim 8, wherein the fuel element has a plurality of longitudinally extending passages therethrough. The article of claims 3 or 4 further comprising a heat conducting member for conducting heat from the fuel element to the aerosol generating means.

11. The article of claim 10, wherein the heat conducting member is metallic and contacts both the fuel element and the aerosol generating means.

12. The article of claim 11, wherein the heat conducting member is a metallic foil which encompasses at least a portion of both the fuel element '.nd the aerosol generating means.

13. The article of claim 12, wherein the metallic member encloses a substrate bearing the aerosol forming material. >14. The article of claim 12, wherein the heat conducting member is a metallic rod embedded within at least a portion of both the fuel element and the aerosol generator means. o0o0 15. The article of claim 12, wherein the fuel element is less than about 15 mm in length.

16. The article of claim 1, 2, 3, or 4, wherein the aerosol s. generating means is at least partially contained within a cavity in the I 8L o fuel element.

17. The article of claim 1, 2, 3 or 4, wherein the aerosol generating means comprises a porous, nonparticulate substrate, having a °o longitudinal passageway at least partially therethrough.

18. The article of claim 1, 2, 3 or 4, wherein the article delivers at least about 0.6 mg of wet total particulate matter in the first thr@e puffs under FTC smoking conditions. |i 19. The article of claim 18, wherein the article delivers at least about 1.5 mg of wet total particular matter in the first 3 puffs under FTC smoking conditions. The article of claim 1, 2, 3 or 4, wherein the article delivers an average of at least about 0.8 mg per puff of wet total particulate matter under FTC smoking conditions, for at least 6 puffs.

21. The article of claim 1, 3 or 4, wherein the aerosol generating TMR/332t i i 1 t -46- means contains a substrate loaded with from about 35 mg to 85 mg of aerosol former.

22. The article of claim 1, 3 or 4, wherein at least about 15 weight percent of the aerosol former is delivered as wet total particulate matter under FTC smoking conditions.

23. The article of claim 1, 3 or 4, further comprising a charge of tobacco located between the mouth end of the fuel element and the mouth end of the article.

24. The article of claim 1, 3 or 4, wherein the fuel element produces substantially no visible sidestream smoke during smolder. The article of claim 3, 4 or 5 wherein the fuel element comprises a carbon-containing material.

26. The article of claim 25, wherein the length of the fuel element is less than 20 mm.

27. The article of claim 25, wherein the length of the fuel element is less than 15 mm.

28. A smoking article comprising: S a fuel element having a lighting end and being a pressed or extruded S carbonaceous mass and being less than 30 mm in length prior to smoking for generating heat throughout smoking; and a physically separate aerosol generating means including a thermally stable substrate bearing an aerosol forming material, said aerosol oo o generating means being adjacent and/or contacting the non-lightingend of i o the fuel element so that the aerosol forming material receives heatA and heated gas from the fuel element. o 29. The smoking article of claim 28 additionally comprising a heat conducting member for transferring heat from the fuel element to the aerosol generating means.

30. The article of claim 29 additionally comprising an insulating member which surrounds at least a portion of the fuel element.

31. The article of claim 29 wherein the fuel element comprises at least 65 percent carbon by weight.

32. The article of either of claims 28 or 29, wherein the fuel element comprises at least 70 percent by weight carbon.

33. The article of any one of claims 29 or 30, wherein the fuel element comprises at least 70 percent carbon by weight. TMR/332t dI 47

34. The article of claim 32, which produces wet total particulate matter having no mutagenic activity, as measured by the Ames test. A smoking article for use with a separate mouthend piece, said smoking article comprising: a carbonaceous fuel element, and a physically separate aerosol generating means including a substrate bearing an aerosol forming material, wherein the fuel element and the substrate are arranged in a conductive heat exchange relationship such that the heat stable substrate receives conductive heat transfer substantially throughout the time of burning the fuel element.

36. The smoking article of claim 35 when used with a disposable mouthend piece.

37. The smoking article of claim 35 when used with a reusable o° ~mouthend piece.

38. The smoking article of any one of claims 35, 36 or 37 wherein 0 oO:o the fuel element is less than 30 mm in length.

39. A smoking article for use with a separate, disposable or reusable mouthend piece, said smoking article comprising a combustible fuel ooo 4,00 element less than about 30 millimeters in length adjacent to a physically separate aerosol generating means fixedly coupled to said combustible fuel viQ Cnd(AVH04 element, the aerosol generating means being arranged to receive heat 4 from the fuel element. -o o40. The smoking article of claim 39 when used with a means for 09 °o delivering the aerosol produced by the aerosol means to the user.

41. The smoking article of claim 39 or 40 further comprising a heat o conducting member for conducting heat from the fuel element to the aerosol generating means.

42. The smoking article of claim 41 wherein the heat conducting member overlaps the periphery of the fuel element and contacts the aerosol generating element.

43. The smoking article of any of claims 39 to 42 wherein the fuel element has a length less than about 20 millimeters.

44. The smoking article of any one of claims 39 to 43 wherein the aerosol generating means in in a heat exchange relatiohship to the fuel element. TMR/332t 48 A unitary smoking article for use with a reusable mouthend piece, said smoking article comprising a fuel element adjacent to a physically separate aerosol generating means including an aerosol forming Vi C-oAdc'fion material, the aerosol generating means being arranged to receive heatAfrom the fuel element, and the fuel element comprising at least 70 percent by weight carbon.

46. The cartridge of claim 45 wherein the aerosol generating means is in a heat exchange relationship with the fuel element.

47. The smoking article of either of claims 3 or 4, whereby the aerosol generating means is in a heat exchange relationship with the fuel element.

48. A smoking article, substantially as hereinbefore described with reference to any one of the Examples. DATED this FIFTH day of DECEMBER 1989 R J Reynolds Tobacco Company oars Patent Attorneys for the Applicant SPRUSON FERGUSON T 32 /H R