CA1292163C - Smoking article with improved aerosol forming substrate - Google Patents

Abstract

SMOKING ARTICLE WITH IMPROVED AEROSOL FORMING SUBSTRATE

ABSTRACT OF THE DISCLOSURE

The present invention relates to an aerosol producing substrate for use in smoking articles and to methods of preparing the aerosol producing substrate.
Preferred smoking articles which employ the aerosol producing substrate of the present invention are capable of producing substantial quantities of aerosol, both initially and over the useful life of the product, without significant thermal degradation of the aerosol former and without the presence of substantial pyrolysis or incomplete combustion products or sidestream aerosol. Thus, such smoking articles provide the user with the sensations and benefits of cigarette smoking without burning tobacco.

Description

~2~

SMORIN~ ARTICLE WITH IMPROVED
AEROSOL FORMIN(: SUBSTRATE

BACRGROUND O~ T~IE INVENTION

The present inventiorl relates to an aerosol producing substrate materiaJ. for use wi~h a smokîng article and in particular to a porous carrier material ha~ing substan~ially absorbed wit:hin its pores a S toba~co ~lavor material and a non-aqueous, non-kobacco aero~ol ~orming material. The present invention also r~late~ to methods o~ preparing the aerosol producing ~ubs~rate and, in part~cular, to a one-step and two-step approach. Such substrate materials are especially useful in making smoking articles that produce an aero ol resembling ~obacco smoke, but which - contain no mo~e than a minimal amount of incomplete combustion or pyrolysis products.
: Clgarette-like smoking articles ha~e been proposed or many yearsr especially during the last 20 to 30 ; y~ars. See for e~ample, ~.S. Patent ~o, 4,079,74~ to Ralner et al; ~.S. Patent 4,284,089 o Ray; U.S, Patent . 2,907,686,to Siegel, ~.5. Patent Nos. 3,258,015 and 3,356,094 to Ellis e~ al.; U.S. Patent No. 3~516,417 ~o Moses; ~.S. Patent Nos. 3,943,941 and 4,044,777 to 80yd et al.; ~S. Patent ~o. 4,236,604 to Ehretsmann et al,;
~OS. Patent NoO 4,32~,5~4 to ~ardwick et al.; ~.S.
Pat~nt NoO 4,340,072 to Bolt e~ al., ~.S. Patent No.
4,3~1,285 to Burnett: U.S. Patent No~ 4,474, 191 to St~i~er; and European Patent. ~ppln. No. 117,355 ~earn~. -.

--2-- .

As far as the present inventors are aware, none of the foreyoing ~moking articles or tobacco substitutes have ever realized any commercial success and none have ever been widely marketed. The absence of such smoking articles from the marketplace is believed to be due to a variety of re~ons, including insufficient aerosol generation, both initially and over the life of the product, poor taste, off~taste due to thermal degradation of the smoke former and~or flavor agents, o the presence of Rubstantial pyrolysis products and s~destream smoke, and unsightly appearance.
q~hus, despite decades of interest and effort, there is till no smoking article on the market which provides the benef its and advasltages associated with conventional cigarette smoking, without delivering considerable quantitles of incomplete combustion and pyrolysi s pr oduct 8 .
In lat~ 1985, a series of foreign patents were granted or registered discloqing novel smoking articles 2û capable of providing the bene~its and advantages a3soclated with converltional cigare~te smoking, withou~
dellvering appreciable quantities of incomplete com~ustion or pyrolysis products. The earliest of these patent was Liberian Patent ~o. 1398S/3890, issued 13 September 1985~ This patent corresponds to a later published European Patent Application, Publication No. 174,645, published 19 ~arch 1986.

SUMMARY OF T~E INVENTION
The present lnve~tion relates to an aerosol producing sub~trate material for use with a smoking ar~icle, and in particular to a porous carrier material having ~ubstantially absorbed within its pores a ~2~Z~6~
-3- ;

tobacco flavor material and a non-aqueous ~ non tobacco aerosol forming material. The present invention also relates to methods o preparing the aeros~l producing substrate and, in particular, to a one-step and 5 tW0-5tep approach. Smoking articles which employ the aero~ol producing substrate o~ the present inven~ion are capable of producing substantial quantities of aerosol, both inltially and over the useful life o~ the product, preferably without significant thermal lO degradation of the aerosol former and without the presence of ~ubstantial pyrolysls or incomplete comblustion products or sldestream smoke~ Such smoking article~ provide the user wl~h the sensations and benefit~ of cigarette smok~ng without the necessity o lS burnlng tobacco.
The present lnvention provldes improved aerosol generation in smoklng devices other than conventional cigarettes, cigars and pipes by providing an improved aerosol producing substrate which bears a tobacco flavor materlal and a non-aqueous, non-tobacco aerosol former material. The aerosol producing subs~rate pr~p~red in accordance with the present inven~ion pro~ides the ability to control bo~h the quantity and characteristics of ~he aerosol produc~d during smoking by facilltating un~form applica~ion of the tobacco flavor material to the substrate, which in turn, provides improved release o~ aerosol during smoking of the product without any appreciable undesirable burning or scorching of the tobacco flaYor material.
Preferred smoklng devices which employ the aerosol produclng substrate of the present invention comprise an aerosol generat~ ng means which includes the aerosol producing substrate. Thiq combination produces a smoke-like aeroRol, having the aroma, flavor, ~Z~3 appearance; throat impact and feel o~ tobacco smoke, but preferably without production of substantial levels of tobacco pyrolysis products. The carrier material employed to prepare the aerosol producing substrate should be porous and should be prepared from a material which is conduclve to sorption of the tobacco flavor material and the non-aqueous, non-tobacco aerosol forming material. Preferably, the carrier material is inert to the tobacco flavor material and other aerosol products produced, and is thermally stable a~ ~he ~emperature~ encountered during the use of smok:ing articles employing the aerosol produclng substrate.
Suitable carrier materials include carbon, alumina, sil$ca, ceramlc, vermiculite~ clay, and the like.
Ac~ivated c~rbon and slntered alumina are preferred carrier materials.
In preferred em~odiments, the carrier material is mixed with an admixture or slurry of i) a tobacco 1avor material whlch may be commlnuted tQbacco, tohacco ex~rac~ (elther aqueous or organic, e.g., alcohol), sp~ay dried tobacco ex~xact~ or the lik , and il) a non-aqueou~, non-tobacco aerosol forming material such as g~ycerin, propylene glycol, triethylene glycol, and the like. It has been found that the aerosol 25 producing substrate prepared in accordance with the present inven~ion lmproves the performance of these articles in terms of (a~ taste, (b) economy, in the use of materials in the aerosol generating means, (c) the eas~ o~ delivering di~ferent types of tobacco flavors including blend~ thereof, (d) the ability to deliver a consistent taste and amount o~ aero~ol, both initially and over the u6eful life of the produc~ and ~e) reduction of migration of the aerosol forming ma~erial a~d other volatile~ to the uel source and other portions of the smoking article.
The aerosol producing substrate of the present lnvention may be prepared by a variety of methods, but preferably is prepared using a one-'step or two-step 5 approach. In the one-step approach, the tobacco flavor material is preerably mixed with a non-aqueous, non-tobacco aerosol formlng material to form a slurry.
The slurry is then applied to a carrier materlal by mixing, spraying or by similar techniques until the 10 slurry i8 substan~ially absorbed by the carrier. In the two-step approachJ the tobacco flavor material ~hich is preferahly in solid particulate form, e.g.
spray dried tobacco extract, is initially mixed with water ~or other sultable liquid) to form a slurry. q'he 15 slurry is then applied to a carrier material as in the one-step approach. The water or other liquid is th~reafter substantially removed by appropriate means, e.g. dried in conventional ovens, and the non-aqueous, non-tobac.co aeros~l forming materlal is added in a 2û second step. In a variation of the two-step approach, the tobacco flavor material may be applied to the carrier by condensa~ion of a vapor of ~he tobacco i~lavor material onto the carrier and thereafter the non-tobacco aero~ol formlng material added in a second 25 st~p.
In general, smoking articles ukillzing the aerosol prG~ucing sub~trate prepared in accordance with the present invention include ~1~ a fuel element; ~2) a phy3ically separate aerosol generating means including 30 the aerosol produclng substrate of the present invention; and ~3) an aerosol delivery means such as a lon~itudinal pa~sageway in the form of a mouthend pieS~e. Preferably the smoking article is of the clgarette type, which utillzes a short, i,e., less than ~.%~ ii3 about 30 mm long, preferably carbonaceous, fuel element in con~unction with a physically separate aerosol generat$ng mean.~. which utilizes the aerosol producing substrate of the present inventionj and which is preferably in a conductive heat exchange relationship with the fuel element.
Preferred smoking articles employi.ng the aerosol producing substrate of the present invention are capable of delivering at least 0.6 mg of aerosoll measured as wet total particulate matter (Wl'PM), in the first 3 puffs, when smoked under FTC smoking conditions, which consis~ of 35 ml puffs of two seconds durati'on, separated by 58 seconds oE smolder. More preferably, embsdiments of ~he invention are capable of lS delivering 1.5 mg or more of aerosol in the first 3 puffs. Most preferably, embodlme~ts of the invention are capable of delivaring 3 mg sr more of aerosol in the first 3 puffs when smoked under F~I~C smoking - ct)nditions. Moreover, preferred embodiments of the invention dellver an average of at least about 0.8 mg o~ Wl'P~ per puff for at least about 6 pu~fs, preferably a~ l~ast about 10 puff3t under FTC smoking conditions.
In addition to the aforementioned benefits, preferred c,Taoking articles of the present invention are 25 . apable o~ providing an aerosol which is chemically simple, conslstlng essen~ially of air, oxides o~
carbon, water, the aerosol former, any desired flavors or other desired volatile materials, and trace amounts of c.ther materials. The aerosol pref erably also has no 30 3ignificant mutagenic as:tivity as measured by the Ames q'es~. In addition, preferred articles may be made virtually ashlese., so that the user does not have to r emo~e any ash dur ing use ~
~ s used herein, and only for the purposes of this ~ Z~L63 applicatlon, "aero~ol~ 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 wlthin the aero~ol generating means, or elsewhere ln the article. A~ so defined, the term "aerosol" also includes volatile flavoring agents and/or pharmacologically or physiologically ac~ive agents9 irrespective o whether they produce a visible aerosol.
As used herein, the term ~tobacco flavor material~
m~ans those materials which provide a tobacco~type taste, including, but not llmited to comminuted 15 tobacco, tobacco extract including aqueous andJor organic extracts, spray dried tobacco extract, and the like.
I~B used herein, the term "substantially absorbed wlthin" means substantially absorbed within the pores o~ the carrier material and no~ substantially on exterior ~urfaces of the carrier material.
As used herein, the phrase "conductiYe heat exchange relationshlp~ i~ defind as a physical arrangement of th~ aero~ol generating means and the 2S fu~l element whereby heat is tran~ferred by conduction from the burning fuel element to the aerosol generating means substantlally throughout the burning period of the fuel element~ Conduc~ive heat exchange relationships can be achieved by placing the aerosol generating means in oontact with the fuel element and thu~ in close proximity to the ~urning portion of the fuel element, and/or by utilizing a conductive member to trans~er heat ~rom the burning fuel to the aerosol generating means. Preferably both methods of providing ~92~63 conductive heat transfer are used.
As used herein, the term "carbonaceous~ means primarily comprising carbon.
A~ used hereln, the term "insu:lating member"
applie~ to all materials which act primarily as insulators~ Preferably, these materials do not burn dur~ng use, but they may include slow burning carbons and like materials, as well as mater:Lals which fuse during use, such as ~ow temperature grades of glas~
10 fibers. Sultable insulators have a thermal conductivity in g-cal ~sec) ~cm2) ~C/cm), of less than about 0.05, preferably less than a~out 0.02, most pr~ferably less than about 0~005O See, Hackh's Chemical Dic~lonary 34 ~4th ed., 19693 and Lange's Randbook of Chenli~tr~ 10, 272-27~ ~llth ed., 1973).
The aerosol producirlg substrate and method of the pre~ent invention are described in greater detail in the accompanying drawing~ and the detailed description of the invention whlch follow.
BRIEF DESCRIPTIO~ OF T~E DRAWING

Flgure 1 i9 a longitudinal view of one preferred smoking article whlch may employ the aerosol producing sub~trate of the present invention.
~ igure lA illu~trates, from the lighting end, a preferred fuel element passageway con~guration.

DETAILED DESC~:IPTIOM OF THE PR~ERRED EM~ODIMENTS
In the one-step approach for producing the aerosol producinq substrate of the present invention, a slurry is preferably prepared by admixing a non-aqueous, non-~obacco aesosol former, ~uch as glycerin, propylene ~2~3~ 3 g glycol, tri-ethylene glycol or mixtures thereof, with a tobacco flavor material such as spray dried tobacco extract, commlnuted tobacco, tobacco extract or the like. Spray drled tobacco ls preferred. High-shear mixlng is preferred, with simultaneous input of heat to reduce th~ ~isco~ity of the slurry. A preferred machine for mixing these mater1als is the Bxeddo Likwifier t~reddo Food Products, ~ansas City, Kansas), model LORWW, 30 horsepower, with jacketed tank lO ~ection~ A sufficient amount of a porous non-tobacco carrier material, such as carbon, activated carbon, alumina or the llke is added to the slurry and mixed until the slurry is ~ubstantially absorbed within the pores of the carrier material and the resultant aerosol 15 pro~ucing substrate ls flowable. A medium-shear, low impact mixer i5 preferred in order to uniformly ~ix the slur~y and carrier with minimal breakage of the carrier ma~erial. One such mixer is the Littleford model FM-.l30 D ~L~ttle~ord Brothers? Florence~ Rentucky).
20 When aerosol producing sub~trate preparation is ~o~plete the 6ubstrate normally appears dry on the R~lrCace~ and the aerosol producing substrate is ~ub~tantially free flowing.
Alternatively, and depending on the viscosity of the particular slurry, the carrier may b~ sprayed with the slurry uslng conventio~al spraying systems~
Similarly, other techniques known in the art may be used to apply the slurry to the carrier.
Depending on ~he non-aqueous, non-tobacco aerosol 30 forming material u~ed, it may be desirable to heat the slurry prlor to and/or during mixing with the carrier.
The t~mperature may range broadly depending on ~he viscosity of the slurry. For example, when the slurry comprises a mixture of glycerin and spray dried tobacco - ~Z~23L~;3 extrart, heating the slurry to a temperature of about 40~ C has been found to facilitate absorption of the slurry by the carrierl Excessive temperatures should, however, be avoided in order to prevent thermal decomposition of the slurry components.
As noted above, the preferred toba~co flavor materlal for the one-step method is spray dried tobacco extract. Spray drled tobacco extracl~ is pre~erred since, in general, it is desirable to have an aerosol producing substrate with a final water content of less than about 10~ by weight, preferably less than about 5%
by weight and most preferably less than about 2~ by weight~
In the two-step approach, a slurry is prepared in a lS flrst step by mixlng the tobacco flavor material with water or other ~ultable liquid ~uch as alcohol. This approach is part~cularly advantageous when spray dried to~acco extract 1~ used, since spray dried tobacco ~xtract is substantially soluble in water, which, in turn, results in greater absorption ~y the carrier ma~erial. This ~pproach also facilltates ease of application of the slurry to the carrier since the slurry formed i5 le~s viscous or sticky.
The amount of pray dried tobacco extract to water may vary broadly depending on the type of spray dried tobacc~ extract and on ~he carrier material used to absorb the slurry. For example, for every 25 9 of water the amount of spray dried tobacco extract may ranc~e from 1~0 g to 16.0 g, preferably from 5.0 g to 30 12.0 y, and mos~ preferably from 7.0 g to 3.Q g. The spray dried tobacco extract should be mixed with water - 80 a~ to provide a uniform dispersion, and prevent the formation of lump~ Stirring ~ay be accomplished by a magnetic 3 irrer or other suitable means.
Alternatively, an aqueous tobacco extract, may be 2~3 used in lieu of the spray dried/water slurry and applied directly to the carrier, thus eliminating ~he spray drying step, infra. Any of a number of conventional mixers may be used to mix the slurry with the carrier material. A preferred mixer is the Patterson-Kelly Zig-Zag blender, model CLS
~Patterson-Relly, Inc., East Stroudsbury, PA) with the dog-leg st~le intensifier bar protrusions removed to reduce degradation of the carrier material~
Conventional liquid and solid metering con~rols are preferably used to assure delivery of the desired rates and proportions of the components.
After mixing, the substrate~slurry is dried by appropriate means to reduce the moisture content to less than about 10~ by weight. Preferably, the final water content less than about 5% by welght, most preferably less than about 2~ by weight. ~rying may be achieved in conve~tional oven~, i.e~ convection ovens, at temperatures of about 95C or in fluidized bed 20 driers such as an MBD 400 availat:)le f rom Fuj i Paudal RR, Japan~ Excesslvely high temperatures, i.e. in excess of about 115C for long duration, should be avoided since nico ine and other desirable tobacco flavor components may b~ driven off at such 25 temperatures.
In the second step, the non-tobacco aero~ol forming material and other desired flavors or other additives are added to the carrier containing the dry tobacco flavor material and mixed in a suitable blender such as the Patterson-Relly Zig-Zag blender descrihed above.
In a variation of the two-step approach, the tobacco flavor material is incorporated into the carrier material in a first step by forming a vapor of the tobacco flavor material and contacting the vapor with the carrier, The tobacco ~lavor materlal vapor is allowed to condense on the carrier and the non-tobacco ae~osol forming material is added in a second step as descrlbed above.
The preferred tobacco flavor material component of the slurry is spray dried tobacco extract. Other tobacco flavor materials .inclu~e comminuted tobacco, tobacco extract including aqueous a~d/or organic extracts, freon extract of tobacco, freeze-dried tobacco extract and the l$ke.
The preferred non-aqueous, non tobacco aerosol forming materials include polyhydric alcohols, or mixtures of polyhydric alcohols. More preferred non-tobacco aerosol formers are selected from glycerin, trlethylene glycol and propylene glycol.
The weight ratio of tobacco flavor material to aero~ol forming material prepared either by the one-step or two-step method may vary broadly depending.
on the tobacco ta~te desired. In general, the weight ratio of to~acco flavor material to aerosol forming material is i~ the range between about 1:100 and 3:1, pre~erably between abcut 1:30 and 201, most preferably bet~leen about 1:4 and 1:1.
One preerred ca~rier material is a high surface area alumlna, ~uch as a product of W.R. Grace ~ Co.
designated as SMR-14-1896, having a surface area of about 280 m~/g. This alumina (-14 to +20 mesh) is treated to make lt suitable for use in the aerosol producing ~ubstrate of the present in~ention by sintering for about one hour at an elevated 30 temperature, e.g., yreater than 1000C, preferably from about 1400C to 1550C, followed by appropriate washing and drying. Preferably, the sur~ace area of the treated alumina is less than about 50 m2/g and the medlan pore diameter ~volume) is ~33Z~ 3 geeater than about 0.1 microns.
When ~he above treated alumina is used as the carrier material, the aerosol producing substrate of the present invention prepared either by the one-step or two-s-~ep approach generally comprises about 20 to 90 weight percent alumina, about 5 to 50 weight percent non-aqueous, non-tobacco aerosol forming material and about 0.1 to 20 weight percent tobacco 1avor material. Preferably, the aerosol producing sub~trate comprise~ about 50 to 75 weight percent alu~ina, about to 30 weight percent non-aqueoLls, non-tobacco aerosol forming material and about 0.5 to 15 weight percent tobacco flavor material. Most preferably, the aerosol producing substrate comprises about 65 to 70 weight percent alumina, about 15 to 25 weight percent non-aqueous, non-tobacco aerosol forming material and about 7 to l0 weight percent tobacco ~lavor material.
Other preferred carrier materials include carbo~s such as PG-60 from Union Carbide and ac~iva~ed carbons such as APC from Calgon Corporation. Such~caxbon ma~erials are preferably ~rea~ed to make them suitable ~l5J~t~
for use in ~he aerosol producing substrate of the present inven ion by heating the material in a non-oxidizing a~mosphere for about one hour at an elevated te~perature, e.g., greater than 1000~C, preferably greater than 1800C, and mos preferably at about 2500C followed by appropriate washing and drying. Pre~erahly, ~he surface area of the treated activa~ed carbo~ is less than about ~00 m2/g.
~hen the above treated carbon is used as the carrier material, the aerosol producing substrate of the present invention prepared either by the one-step or two-step approach generally comprises about 15 to 75 weight percent carbon, about 5 to 45 weight percent ~2~Z.ll~;3 non-aqueous, non-tobacco aerosol forming material and about 0.1 to 15 weight percent tobacco flavor ma~erial~ Preferably, ~he aerosol producing subs~rate comprises about 40 to 65 welght percent carbon, about 7.5 to 25 welght percent non-aqueous, non-tobacco aerosol forming material and about OJ4 tO 13 weight percent tobacco flavor material. Most preferably, the aerosol producing substrate comprises abou~ 55 to 60 weight pe~cent carbon, about 10 to 20 weight percent non-a~ueous, non-tobacco aerosol formlng material and abcut 6 to 8.5 weight percent tobacco flavor material.
~ he aerosol producing substrate may also include one or ~ore addlt~onal volatile flavoring agents, such as menthol, vanillin, artlfcial coffee, tobacco extracts, nicotine, caffeine, llquor~, and other agents to impar~ flavor to the aerosol. There may also be included any other desirable volatile solid or liquid materials. Such optional agents may also or alternatively be added separately to. the aerosol generating means or placed between the aerosol generating means and the mouth end, such a~ in a seE~arate substrate or chamber or coated within the pa~sageway ~eading ~o the m~uth end, or in an optional tobacco charge which may be employed down~tre~m rom th~ fuel element.
Similarly, varlous acids or salts thereof may be i~cluded in the aerosol produc~ng substrate, e.g. in the slurry, in order to smooth out the taste and physiological effects of the aeroaol. Such materials include levulinic àcid, caffeic acid, chlorogenic acid, benzoic acid, Malic acid~ lactic acld, ~umaric acid, glu~ose pentaacetate, sodium octaacetate and the lik~. The amount of such material by weight percent of the treated ubatrate may range broadly between 0.5 LEi3 and 3.0%, preferably between 0.5 and l.S%, and most preferably about 0.8%. It has been found, for example~
that add~tion of about l.S% of levulinic acid ~ lncluding the weight of the substrate) yields a smoke pH approximately equivalent to conventional cigarette smoke.
~ dvantageously, the aerosol producing substrate of the present invention may be coated with a substance such a~ graph~te, ethyl celluloset tobacco waxes and the like. Such coatings further reduce migration of aerosol formers, nico ine, flavors, and ~he like from the aerosol producing substrate to the fuel source~
Mor~over, such coatings reduce the uptake of moisture and may aid in heat transfer as between the indiv:Ldual par~icles of the substrate, particularly when the treated ~ubstra~e ls coated wlth substances such as gra~hite. Such coatings.can be applied by conventional coat~g p~ocesse~ depending on the particular coating to be applied.
~Q Preferred c~garette-type smoking articles which may employ the modi~ied substrate of the present invention are de~cribed in th~ following paten~ applications:

~icants Serial No. Filed Sensabaugh et al. 650,604 September 14, 1984 Shannon et al. 684,537 December 21, 1984 Banerjee et al. 891,073 July 28, 1986 Sensabaugh et al. EPO 85111467.8 Septem~er 11, 1985 . . (pu~l~qhed 3tl9/86) the disclosures of which are hsreby incorporated by reference.
One such preferred cigarette-type smoking article ~Z1~3 is set forth in Figure i accompanying this specification. Referring to Figure 1 there is illustrated a cigarette-type smoklng ar~icle having a small carbonaceous fuel element 10 with several passageways 11 therethrough, preferably about thirteen arranged as shown in Figure lA~ This i-uel element is formed from an extruaed mixture of carbon ~preferably from carbonized paper), sodium carboxymethyl cellulose . ~SCMC) binder~ R2C03, and water, as described in the above referenced patent applicationsc The periphery 8 of fuel element 10 is encircled by a resilient ~acket of insulating fibers 16, such as gla5s fibers.
Overlapping a portion of the mouthend of the fuel element 10 is a metallic capsule 12 which contains a substrate material 14 which at least in part comprises the aerosol producing substrate of the present $n~i ention, either in particulate form, or alternat~ vely, in the form of a rod.
Capsule 12 is circumscribed by a jaoket of tobacco 18. Two clit-like passageways 20 are provided at the mou~h end of the cap~ule in the center of the cr imped tube .
At the mouth end of to~acco jacket 18 is a mouthend piece 22 compr~sing an annular section of cellulose acetate 24 and a se~ent of rolled, non-woven polypropylene scrim 26 through which the aerosol passes to the user. The article, or portions thereof, is overwrapped with one or more layers of cigarette papers 30 ~ 36.
Upon llghtlng the a~oresaid embodiment, the fuel element burns, generating the heat used to volatilize th~ to~acco flavor material and any addltional aerosol forming sub~tance or sub~tances in the aerosol ~ ~ Z ~63 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 tran~fer to the aerosol generating 5 means, and resultant production of aerosol, especially when the pref erred heat conducting member is used.
Because of the small size and burning characteristlc~ o~ the fuel element~ the fuel element usually begins to burn over substantially all of its io exposed length withln a few puffs. Thus, 'chat portion of the fuel element adjacent to the aerosol generator becomes hot quickly, whlch sign~ficantly increases heat transfer to the aerosol generator, especlally during the early and middle p~ffs. ~ecause the preferred fuel lS element is so ~hort, there is never a long secti.on of nonburning fuel to act as a heat sink, as was common in ~ome previous thermal aerosol article~0 Because the tobacco flavor ma~erial and any additional aero~ol forming substance~ are physically separate from the fuel element, they are exposed to substantially lower temperatures than are generated by the burning uel, there~y Minimlzing the possibility of ther~l degradation.
In preferred embodiments, the short carbonaceous 25 fuel element, heat conducting member and lnsulating means cooperate with the aerosol generator to provide a system which is capable of producing sub~t~ntial quantities of aerosol r on virtually every puff. The clo.se proximity of the fire cone ~o the aerosol 30 gen~3rator af'cer a few puff~, ~ogether with th~
insulating rneans, results in high heat del ivery both during puffing and during the relatively long period of ~molder between ~uff~.
In general, ~he combustible ~uel elements which may ~IL25~29L63 be employed in preferred embodiments have a diameter no larger than that of a conventional cigarette (i.e., less than or equal to 8 mm), and are generally less than about 30 mm long. Advantageously the fuel element is about 15 mm or less in length, pref~erably about 10 mm or less in length. Advantageously, the diameter of ~he fuel element ls between about 2 to 8 mm, preferably about 4 to 6 nun. The den~ity of th~e fuel elements employed herein may range f rom abo7~ 0 .7 g/cc to about 10 1.5 g~cc. Preferably the density is greiater than about 0.85- g/cc.
The preferred material used ~or the formation of fu2:1 elements is carbon., Preerably, the carbon content oî these fuel elements ls at least 60 to 70%, 15 most preferably about 8096 or more, by weight. High carbon content fuel elements are preferred because they pro~3uce minimal pyrolysls and incomplete combustion pro-~ucts, little or no visible sidestream smoke, and mln~ mal ash, and have high heat capacl ty . ~owever, 20 low~:r carbon content fuel elements e. g., about 50 ~o 60% by weight may be used especially where a minor amolmt of tobacco, tobacco extract, or a nonburning inert f iller is used.
The aerosol generating means ~hich includes the 25 aero~ol producing substrate of the present invention is preferably ~paced no more than 15 mm from the lighting end of the fuel element~, The aero~ol generating means may vary in length from about 2 mm to about 60 mm, preferably from abaut S mm to 40 mm, and most 30 pref erably ~rom about 20 mm to 35 mm. The diam~ter o the aerosol generating means may vary f rom about 2 mm to about 8 mm, preferably from about 3 to 6 mm.
The h~at conduc ing materlal employed as the container ~or ~he aero~ol generating means is typically ~912:~63 --19-- . .

a metallic foll, such as aluminum foil, varying in thickness from less than about 0.01 mm ~o about 0.1 mm, or more, The thickness and~or the type of conducting material may be varied ~e.g., Grafoil, from Union Carbide) to achieve the desired degree of heat transfer.
A~ shown in the illustrated embodiment, the heat conducting member preferably contacts or overlaps the reur portion of the fuel element, and may form the container or capsule which eneloses the aerosol producing ub~trate of the presen~ invention.
Preferably, the heat conducting member extends over no more than ~bou one-hal~ the length of the fuel elemenk. More preferably, the heat conducting member overlaps or otherwise contacts no more than about the re~r S mm, pre~erably 2-3 mm, of the fuel elemen~.
Preferred rece~sed member~ of th~q type do not int.~rfere with the llghting or buxning characteristics of the fuel element. Such members help to extinguish the fuel element when it has been con~umed to the point of contact with the conducting member by ac~ing as a heat ~ink. These membe~s also do no~ protrude from the lighting end of the article eve~ after ~.he fuel element ha~ been con~umed.
~he in~ulatlng member~ employed ln the preferred smoking article~ are pref erably ~ormed into a resilient jacket from one or more layers of an insulatiny material. Advantageously, this jacket is at least about 0.5 mm thick, p~e~erably at least about 1 mm thick.
PreEerably, the jacket extends over more ~han about halE, if not all of the l~ngth of the ~uel element.
More preferably, it also extends over substantially the entire ou~er perlphery of the fuel element and the capsule for the aerosol generating means. As shown in ~92~63 -20- .

the embodiment of Figure 1, different materials may be used to 1nsulate these ~wo components of the article~
The currently preferred insulating materials, paticularly for the fuel element, are ceramic fibers, such as glass 1ber~ Preferred glass f iber are expe~imen~al materials prod~ced by Qwens - Corning of Toledo, Ohio under ~he designations 6432 and 6437, which have softening points of abou~ 650C. O~her ~uitable ln~ulating materials, . preferably non-combustible inorganic materials/ may also be used.
In the most preferred embodiments, the fue~ and aerosol genera~ing means will be attached to a mouthend piece, although a mouthend piece may be provided separately, e.g., ln the form of a cigarette holder for use with disposable fuel~aerosol generating cartridges. ~he mouth snd piece channels the vaporized aerosol formlng substance into the mouth of the user.
Due to it~ length, about 35 to 50 mm, it also keeps the hezt fro~ the fire ~on~ away from ~he mouth and fingers of the use~, and provides some cooling of the hot aero~ol before it zeaches the user.
Suitable mouthend pieces should be lner~ with re~pect to the aero301 formlng subs~ancesr should offer minimum aero~ol lo~s by condensation or filtration, and should be capable o~ withstanding the temperature at the interface with the other elements of the article.
Pre~erred mouthend pieces includ~ the c~llulose acetate - polypropylene scrim combination of Figure 1 and the mouth end pieces disclosed in Sensabaugh et al.
~ur.opean Patent Publ~cation No. 174 ,645 .
The entire length o the article or any portion thereof may be overwrapped wlth cigarette paper.
Preferred papers at the fuel element end should not ope~lly 1ame during burning of the fuel element. In 9L~3 addition, the paper should have controllable smolder propextles and ~hould produce a grey, cigaret~e-like ash .
In those embodiments utilizing an i:nsulatins jacket 5 wherei n the paper burns away from the jac3ceted fuel element, maximum heat trans~er is achi~ved because air ~low to the fuel element ls not res ricted. ~owever, papers can b~ designed to remain wholly or partially lntac~ uponexpo~ure to heat from the burning fueï
elemer~t.Such papers provide the opportunity to r e~ tr i ct ~i r f low to the bur ni ng f uel el ement, the r eby controlling the temp~rature at which the fuel elemlent burn~ and the subsequent heat. transf er to the aerosol generating means.
To reduce the burning rate and temperature of the fuel element, thereby maintaining a low CO~CO2 ratio, a non-porous or zero-porosity paper treated to be ~llghtly porou~, e.g., noncombu3tible mica paper with a plurality of h~les therein, may be employed as ~he ~o overwrap layer. Such ~ paper con~rols heat delivery, espe~ially in the middle puffs (i.e., 4 - 6 To maxi~ize aerosol delivery, which otherwise could be diluted by radial ~i.e~, outside) air in~lltration through the artlcle, a no~ porous paper may be used ro~ the aerosol generating mean~ to the mouth end~
Papers such a~ these are known in the cigarette and/or paper arts and mixtures of such papers may be employed for various functional effec~s. Preferred pap~rs used in the articles of the present invention indude RJR Archer's 8-0560-36 Tipping with Lip Release pap~rl Ecusta' ~ 646 Plug Wrap and ~CtUSTA 01788 manll~a~t ured by Ecusta of ~isgah Forest, NC, and ~mberly-Clark' s P858-16-2 and P878-63-5 papers.
The aerosol produced by the preferred articles of -~2- .

the present lnvention is chemically simple, consisting essentially of air, oxides of carbon, aerosol former including any de~ired flavors or other desired volatile materials, water and trace amounts of other materials.
~he WTPM produced by the preferred articles of this lnvent~on has no m~agen~c activlty as measured by the Ames test, i~e., there is no significant dose response relationship between the WTPM produced by preferred articles of the present invention and the number of 1~ revertant9 occurring in standard test microo~ganisms exposed to such products. ~ccording to the proponents of the Ames test, a ~ignificant dose dependen~ response indicates the pre~ence o~ mutageni~ ma~erials ln ~he products tested. See Ames et al., Mut. Res., 31: 34-7 -364 ~}975); Nagao et al., Mut. Res~, 42: 335 ~1977~.
~ fur~her benefit f~om the pre~erred embodiments ofthe present invention is the relative lack of ash produced during use in comparison to ash from a conventional cigaret e. ~9 the preferred car~on fuel 20 elemeQt is burnedt it is essentially converted to oxides of carbon, with relatively little ash gen~ration, and ~hu~ t~ere is no need to dispose of a~he~ while uslng the article.
The use o~ the substrate material of the present invention ln clgarette-like smoking articles will be further $11ustrated with reference to the following examples which will aid in tbe understanding of the pgesent invention, but which are no~ to be construed as ~ llm~tation the~eof~ All percentages reported herein, 30 unle~s o'cherwise sp~cified, are percent by weight~ All tempera~ures are expressed in degrees Celsius and are uncor r ect ed .

~2~2~.6~
--~3--.
~XAMPLE I

A smoking article of the type ~llus~rated ln Figure 1 wa~ made in the following manner.
S
A. Fuel Source Preparation The fuel element ~10 mm long, 4.5 mm o~d.~ having an apparent (bul~ density of about 0.86 gJcc, was prepared from carbon ~90 wt~ percent), SCMC binder ~10 w~. percent) and R2CO3 tl wt. percent).
The carbon was prepared by carbonizing a non-talc conta~ning grade of Grand Prairl~ Canadian ~raft hardwo~d paper under a nitrogen blanket, at a step-wise increasing tempera~u~e rate o~ about 10C per hour to lS a final carbonizing temperature of 7~0C.
After cooling under nitrogen to le~s than about 35C, the carbon was ground to a mesh ~Ize of minus 200~ The powdered carbon was then heated to a temperature.of up ~o about 8S0C to remove volatiles.
After cooling under n~trogen to le~s than about 35C, the carbon was ground to a fine powder, l.e., a powder having an average particle 3ize of from about 0.1 to 50 microns.
~his ~ine powder wa~ admixed with ~ercules 7~ 5CMC
binder ~9 part~ carbon : 1 part binder~, 1 wto percent R2C~3, and sufficient water to make a s~i~f, dou~h-like paste.
Fuel elemen~ were extruded from this paste having sevon large central holes eac~ about 0.021 in. in di~neter and 8i~ peripheral holes each about 0.01 in.
ln diæneter. The web thickness or spacing between the lnner hole~ wa3 abou~ 0.008 in. and the average outer web thlckness ~the spacing between the periphery and hole~ was 0.019 in. a~ shown i~ Figure lA.

--24-- .

The~e fuel elements were then baked-out under a nitrogen atmosphere at 9û0C for three hou~s after f oxmati on .

s . Spr ay Dr i ed Ext r act Tobacco t~urley, Fllle Cured, Turkish, . etc, ) was ~round to a medium dust and extracted with water in a et~inless steel tank at a concentra~iorl of ~rom about 1 - to l.S pounds tobacco per gallon wal:er. The ~xtraction wafi conducted at ambient temperature u~ing mechanical agitat~on for f rom about 1 hour to about 3 hours. The admixture wa8 c~ntrifuged to remove suspended solids an~; the aquevus extraot was spray dried by continuously pu~ping the aqueous solution to a conventional spray dr~ er, such as an Anhydro Size ~o. 1, at an inlet temperature of from about 215 - 230C and collecting ~he dried powder material at the outlet of the drler. The outlet temperature varied f rom about 82 _ goO~
c~
~ igh surac~ area alwnina ~surface area of about 2~0 ~/g) from W~Ro Grace ~ Co. tdeslgnated S~R-14-1896), having a ~esh ~ize of from -8 to *14 25 (~.S.) was sintered at a soak temperature a~ about 140ûC to 15~0C for abou~ one hour and cooled.
The surface area of the modi~ied all~mina was appro~imately 4.0 m2/gO The alumina was washed with wat~r and dried. In a flrst s ep, an as~ueous sc~lution 30 contalning 107 mg o~ Rpray dried flue cured tobacco ext::act was mixed with ~he ~intered alumina ~640 mg~
and 'cherea:Eter dried to a moisture con~en~ of about wei 3ht pereen~v In a second ~tep, this material wa~
mix ~d with 233 n~g of glycerin and 17 mg of a flavor comoonent obtained from Firmenich, Geneva, Switzerland, ~2~L63 under ~he designation T69-22 until substantially absorbed within ~he tobacco f lavor contalnlng alumina, to produce the aerosol p~oduclng substrate of the pr~sent invention.

I)o Assemblv The capsule used ~o construc~ the E'igure 1 smoking article was prepared from deep drawn aluminum,. The capsule had an average wall thickness of about 0.004 ina ~0.01 mm), and was a~out 30 mm in length~ having an outer diameter of about 4.5 mm. q'he rear of the container was sealed ~ith the exc:ep~cion o:E two 810t~ lilce openings teach about 0.65 x 3.45 mm, spaced about 1.14 mm apart) tv allow passage of the aerosol 15 former to the u~er. About 325 mg of the aerosol producing substrate described above was used to load the capsule. A fuel element prepared as above, was in~erted lnto the open end of the filled capsule to a depth of abou 3 mm.
B. Insulatlnq Jacket The fuel elemerlt - capsule combination was overwrapped at the fuel element ~nd wi h a 10 mm long, glass f iber jacket o~ Owens-Cornlng 6437 ~having a ~5 -~of l:enlrlg point o~ about 650C), with 3 wt. percent pectin binder, to a diameter of about 7.5 mm. The glass ~iber jacket was then overwrapped with Rimberly Clark P&7~-63-5 paper.

3 o F, ~s5a~
A 7c5 mm diamet~r ~obacco rod ~28 mm long) with a 646 plug wrap overwr~p (e.g., from a non-filte~
cigarette) was modified by insertion of a probe to have a longitudinal passageway of about 4.5 n~m dlameter ther ei n.

i9~3 Go s sembly The jacketed fuel element - capsule combinatl on was in erted into the tobacco rod pa~sageway until t:he S gla~s f iber jacket abutted the toba~cco. The glass fiber and tQbacco sections were ~oined together by Rimberly Clark' s P850-2û8 paper ~a process scale version of 'cheir P878~16-2 paper).
A mouthend piece of the type illustrated in Figure 1~ 1, was cons'cructed by combining two sections; (1) a hollow cylinder of cellulose acetate tlO mm long/7.5 mm outer diame er~4~5 mm inner diameter~ overwrapped with 64~ plug wrap; and ~2) a section of non-woven polypropylene scrim, rolled into a 30 mm long, 7.5 mm d~meter cylinder ove~wrapped with Rimberly-Clark's P850-186-2 papert wlth a combining overwrap of ~imberly-Clark's P850-186-2 paper.
The combined mouthend piece section was joined to th~ jacketed fuel elemen~ -- capsule saction by a final ov~rwrap o~ RJR Archer Inc. 8-0$60-36 tipping with lip relea~e paperO

~ h!a~@
Analysis of alumina type aerosol producing substrate prepared ln accordance with the above t~o-s~ep approach wa~ conducted to determine the uniformity o~ the glycerin aerosol former, water, and s~cay dried tobacco extract as measured by nicotine content. ~esult~ for nine~een samples showed ~hat the 30 gl~cerin, water and spray driad tobacco extract content wa~ substantlally unlform amongst the samples. The av~rage glyc~rin con~en~ was 22.~6 wl3ight percent. The av~r~ga wa~er content was Or63 weight percent. The average spray dried tobacco extract content as measured 2:~1L63 by nicotine content was 0~72 weight percent~

Smoking articles thus prepared produced an aerosol reQembllng tobacco smoke withou~ lany undesirable 5 o ~-tas e due to scorching or thermal ,decomposition o the aerosol formlng material.

~XAMPLE I I

A smoklng article similar to the smoking article de~cribed in Example I was anade in ~he following man~er .

A. Fuel . Source Preearation An extruded carboTI fuel rod was prepared as described in Section A of Example I. The dry, extruded rod was cut into 10 mm lengths and three centrally spaced 0.5~UD holes were dr~lled through the length of the rod.
8. ~m~
The metallic con~alners for the substrate were 3 0 mm long aluminum tubes having a diameter of about 4.5 mm.i One end of each of ~hese ~ubes wa~ crimped to form 25 an end with a small hole. Approxima~ely 200 mg of the ae~ 0801 producing su~strate was used to fill each of th~ container.s. The substrate ~as prepared in ac-.~ordance with the one-step appr~ach as follows.
Gl~ cerin ~8DO grams) waæ admixed with 4 srams of spray 30 dr~.ed . obacco extract prepared as descrlbed in Example I to form a slurry~ 60 granulated carbon (12 grams) wa~ added to the slurry whlch was then stirred un~il the aerosol producing substrate was dry to the touch.
This mixture afforded a 17 wt~ percent tobacco or .63 --28-- .

tobacco extract containing substrate~ After the metallic containers were filled, each was joined to a fuel rod by inserting about 2 mm of the fuel rod into the open end of the container. Each of these units was then ~oined to a 35 mm long polypropylene tube of 4.5 mm internal diameter by inserting one end of the tube over the walled end of the contalner~
Each of these core unitq was placed on a sheet of Manniglas 1200 pretreated at about ~00 ~C for up to about 15 min. in alr to eliminate binder~, and rolled until the article was approxlma~ely the clrcumference of a cigaret~e. An additional double wrap of ~anniylas 1000 was applied around the ~anniglas 1200. The ceramic fiber jacket ~s cut away ~rom 10 mm of the mouth end of the polypropylene tube o tha~ a 10 mm long annular segment of cellulose acetate filter material could be placed over the polypropylene tube.
The mouth end o~ thi~ segment was heaYily coated with cor.ven~ional glue to bloc~ aiF fl~w through ~he fllter mat~rial. A conventlonal cellulose acetate filter plug o~ 10 mm length was butted again~t the adhesi~e. The ent1re unit wa~ then ~rapped with ECUST~ 01788 perforated clgar~te paper, and a conven~ional tlpping wa~ applied ~o the mouthend.
EX~MPLE III

Smoklng articles were prepared as ~n Example II, e~ploying the one-step approach except that the sub~trate ma~er~al u~ilized ln the aeroso} generating m an~ was a ~p~cially treated alumina, prepared as ~01 10~8:

~9~i3 Sinterinq - High area alumina ~surface :area = 280 m2/g) from W. R. Grace ~ Co., havlng a mesh size of from -R to +14 ~U.S.) was - treated for use in the articles of this invention by sintering at elevated t~mperatUreQ as follows. Alumlna was rapidly heated to a soak temperature above about 1400C, pre~erably from about 1400 to 1550C, held at the soak ta~perature for about one hour, followed by rapid cooling, wa~hing and drying.
Loa~ Glycerin ~4.0 grams~ was admlxed wlth grams of spray dr$ed tobacco ex~rac~ ~Flue Cured).
Dried, sintered alumina (15.0 grams) was added to the slurry and s~irred unt~l the alumina was dry to the touch. Approximately 350 mg of such a treated substrate was used to load the metallic capsule.
Ana~y~se~ - An analysis of alumina substrate mixed wlth 3pray dried tobacco extract and glycerin in accordance with the one-step approach was conducted to de~ermine ~pray dried tobacco extract content as 20 measured by nicotine and glycerin content. Based on ten repl icate analy~e~ the average glycerln content was 18.~4 weight percent. The average spray dried content a~ measured by nicotine content was l.ûl welght pe~cent. For comparison purposes an instrument 25 preclsion study was per~ormed prior to the an~lysis lcllroma~ographic) of 'chese samples. The instrulT ent prf?c~sion waq 0.2~ RSD and 2.296 RSD for nicotine and glycerin, respectively. The samples were prepared by ex;laustive (i. ~,, 4 hr. 3haker , 68 hr~ passive) 30 is ~propanol extract$on~

EXAMPLE IV
A smoking article ~as prepared substantially as in Example I, exc~pt 'chat a solid 10 mm long segment - (120mg) of alumina ln ~he ~orm of a rod was used in .

lieu of 'che granular alumina. The rod was prepared as . follows: an alumina hydrate binder tCatapal SB. Vista Chemical COO ~ Houston, Texas) was mixed with alumina from Alcan Chemlcal Products, Cleveland, Ohio 5~designated C-71-UNG) at a ratio of 60:40. ~ixing was done in a roller mill for 4 hours. Peptizing of alumina was achieved by acetic acid treatment. In a muller the alumina hydrate and alumlna sub~trate were mixed with aqueous 5% acetic acid to a 31% moisture content. The 10mix was held for 4 hours at room temperature in an ai~tight container. The mix was extruded ~n thin strands o~ various diame~ers in a ram ex ruder using a Forney compression tester. ~he extrudates were dried at room temperat~re and heated at a chamber temperature of 500C for 3 hour~. ~ea~ing was done ln less than one inch bed depth. The 500C-sintered material was further modlfied by sintering at 1300C for 1 hour to conver~ the alumina fro~ it~ gamma to its alpha form.
The rod was hen treated i~ accordanc~ with ~he two~step method~ The treat~d rod contained 15.4 mg of spray dried tobacco drled to about 4~ moisture conten~
and 46 mg of glycerln (added in the second step)~

EX~MPLE V
2~
Pre~erred cigarette-type smoking articles of the type illu~trated in ~igure 1 employing the aerosol p~o~ucing substrate of the present inYention were prepared s~lbstantially as described in Bxample I:
The carrler materlal for the aerosol generating mean~ wa~ a high surface area alumina ~surface area z 280 m2/g), having a mesh size of from -14, ~20 (V.~.)O Be~ore use h~rein, this alum~na was sintered ~Z~ 2 ~ ~3 for about 1 hour at a soak temperature from about 1400 to 1550C. After cooling, thls alumina was washed with water and dried.
This sintered alumina was combined, in a two s~ep process, with the ingredients ~hown in Table I in the indicated proportlons:

Table I

Alumina 6'7.7%
Glyc~rin 19.0 Spray Dr~ed Extrac 8.5%
Flavoring Mixture 4.2%
Glucose pentaacetate 0.6 Total: 100`,0~

Th~ spray dried extract ig the dry powder residue re~ulting ~rom the evaporation of an a~ueous tobacco extract ~olutionO It co~tains ~ater solu~le tobacco co~p~nents. The flavo~ing mixture is a mixture of flavor compounds which simulates the tast~ of cigarette smoke. One such material used h~rein was obtained from ~irmenich of Geneva, Switzerland under the de~ignation T6~-22.

In the fir~t ~tep, the spray dried tobacco extract wa mixed with s~lficie~t water to ~orm a slurry. This ~l~rry wa~ then a~plied to the alumina carrier 3~ deæcribed above by mixlng until the slurry was un~ormly absorbed by the alumina. The treated alumina was th~n dried to reduce the moistur~ content to about 1 wt. percent. In the second ~ , thi~ treated alumina wa~ mix~d with a ~ombination of the o~her --32-- .

listed ingredients until the liquid was substantially absorbed within the alumina carrier" rhe capsule was ~illed wit~ about 325 mg of this ~ubstrate matarialO

2û

~5

Claims (49)

1. An aerosol producing substrate for use with a smoking article comprising a porous alumina material having substantially absorbed within its pores a tobacco flavor material and a non-aqueous, non-tobacco aerosol forming material.

2. The aerosol producing substrate of claim 1, wherein the carrier comprises particulate material.

3. The aerosol producing substrate of claim 2, wherein the substrate is dry and free flowing.

4. The aerosol producing substrate of claim 1, wherein the weight ratio of tobacco flavor material to non-tobacco aerosol forming material is in the range between about 1:100 and about 3:1.

5. The aerosol producing substrate of claim 4, wherein the weight ratio of tobacco flavor material to non-tobacco aerosol forming material is in the range between about 1:30 and about 2:1.

6. The aerosol producing substrate of claim 4, wherein the weight ratio of tobacco flavor material to non-tobacco aerosol forming material is in the range between about 1:4 and about 1:1.

7. The aerosol producing substrate of claim 1, 2, or 3, wherein the tobacco flavor material is selected from the group of comminuted tobacco, tobacco extract, spray dried tobacco extract and mixtures thereof.

8. The aerosol producing substrate of claim 4, 5 or 6, wherein the tobacco flavor material is selected from the group of comminuted tobacco, tobacco extract, spray dried tobacco extract and mixtures thereof.

9. The aerosol producing substrate of claim 1, 2 or 3, wherein said non-tobacco aerosol forming material is selected from the group of glycerin, triethylene glycol, propylene glycol or mixtures thereof.

10. The aerosol producing substrate of claim 4, 5 or 6, wherein said non-tobacco aerosol forming material is selected from the group of glycerin, triethylene glycol, propylene glycol or mixtures thereof.

11. The aerosol producing substrate of claim 1, wherein the alumina is sintered alumina.

12. The aerosol producing substrate of claim 2, 3 or 4, wherein the alumina is sintered alumina.

13. The aerosol producing substrate of claim 5 or 6, wherein the alumina is sintered alumina.

14. The aerosol producing substrate of claim 11, wherein the surface area of alumina is less than about 50 m2/g and the median pore diameter greater than about 0.1 microns.

15. The aerosol producing substrate of claim 14, wherein the aerosol producing substrate comprises about 20 to 90 weight percent alumina, about 5 to 50 weight percent non-tobacco aerosol forming material and about 0.1 to 20 weight percent tobacco flavor material.

16. The aerosol producing substrate of claim 14, wherein the aerosol producing substrate comprises about 50 to 75 weight percent alumina, about 10 to 30 weight percent non-tobacco aerosol forming material and about 0.5 to 15 weight percent tobacco flavor material.

17. The aerosol producing substrate of claim 14, wherein the aerosol producing substrate comprises about 65 to 70 weight percent alumina, about 15 to 25 weight percent non-tobacco aerosol forming material and about 7 to 10 weight percent tobacco flavor material.

18. The aerosol producing substrate for use with a smoking article, said aerosol producing substrate comprising a porous carbon carrier having substantially absorbed within its pores a tobacco flavor material and a non-aqueous, non-tobacco aerosol forming material.

19. The aerosol producing substrate of claim 10, wherein the carrier comprises particulate material.

20. The aerosol producing substrate of claim 18, wherein the substrate is free flowing.

21. The aerosol producing substrate of claim 18, wherein the weight ratio of tobacco flavor material to non-tobacco aerosol forming material is in the range between about 1:100 and about 3:1.

22. The aerosol producing substrate of claim 21, wherein the weight ratio of tobacco flavor material to non-tobacco aerosol forming material is in the range between about 1:30 and about 2:1.

23. The aerosol producing substrate of claim 21, wherein the weight ratio of tobacco flavor material to non-tobacco aerosol forming material is in the range between about 1:4 and about 1:1.

24. The aerosol producing substrate of claim 18, 19 or 20, wherein the tobacco flavor material is selected from the group of comminuted tobacco, tobacco extract, spray dried tobacco extract and mixtures thereof.

25. The aerosol producing substrate of claim 21, 22 or 23, wherein the tobacco flavor material is selected from the group of comminuted tobacco, tobacco extract, spray dried tobacco extract and mixtures thereof.

26. The aerosol producing substrate of claim 18, 19 or 20, wherein said non-tobacco aerosol forming material is selected from the group of glycerin, triethylene glycol, propylene glycol or mixtures thereof.

27. The aerosol producing substrate of claim 21, 22 or 23, wherein said non-tobacco aerosol forming material is selected from the group of glycerin, triethylene glycol, propylene glycol or mixtures thereof.

28. The aerosol producing substrate of claim 18, 19 or 20, wherein the carbon is activated carbon.

29. The aerosol producing substrate of claim 21, 22 or 23, wherein the carbon is activated carbon.

30. The aerosol producing substrate of claim 18, wherein the carbon comprises particles having a surface area less than about 200 m2/g.

31. The aerosol producing substrate of claim 19, 20 or 21, wherein the carbon comprises particles having a surface area less than about 200 m2/g.

32. The aerosol producing substrate of claim 22 or 23, wherein the carbon comprises particles having a surface area less than about 200 m2/g.

33. The aerosol producing substrate of claim 30, wherein the aerosol producing substrate comprises about 15 to 75 weight percent carbon, about 5 to 45 weight percent non-tobacco aerosol forming material and about 0.1 to 15 weight percent tobacco flavor material.

34. The aerosol producing substrate of claim 30 wherein the aerosol producing substrate comprises about 40 to 65 weight percent carbon, about 7.5 to 25 weight percent non-tobacco aerosol forming material and about 0.4 to 13 weight percent tobacco flavor material.

35. The aerosol producing substrate of claim 30, wherein the aerosol producing substrate comprises about 55 to 60 weight percent carbon, about 10 to 20 weight percent non-tobacco aerosol forming material and about 6 to 8.5 weight percent tobacco flavor material.

36. A method of preparing an aerosol producing substrate material for use with smoking articles, said method comprising the steps of:
(a) forming a slurry of a tobacco flavor material and a non-aqueous, non-tobacco aerosol forming material; and (b) applying the slurry to a porous non-tobacco carrier, the slurry being substantially absorbed within the carrier.

37. The method of claim 36, wherein the porous non-tobacco carrier comprises particulate material.

38, The method of claim 37, wherein absorption of the slurry by the porous non-tobacco carrier is sufficient to produce a free flowing substrate.

39. The method of claim 36, 37 or 38, wherein the tobacco flavor material is selected from the group of comminuted tobacco, tobacco extract, spray dried tobacco extract, or mixtures thereof.

40. The method of claim 36, 37 or 38, wherein the non-tobacco aerosol forming material is selected from the group of glycerin, triethylene glycol, propylene glycol, or mixtures thereof.

41. The method of claim 36, 37 or 38, wherein the porous non-tobacco carrier is selected from the group consisting of carbon, alumina, silica, ceramic, vermiculite, clay, or mixtures thereof.

42. A method of preparing an aerosol producing substrate material for use with smoking articles, said method comprising the steps of:
(a) forming a slurry of a tobacco flavor material and water;
(b) applying the slurry to a carrier material;
(c) reducing the water content of the resulting material to less than about 10% by weight;
and (d) adding a non-aqueous, non-tobacco aerosol forming material to the carrier material, the non-aqueous, non-tobacco aerosol forming material being substantially absorbed within the carrier material.

43. The method of claim 42, wherein the carrier material is a porous non-tobacco carrier.

44. The method of claim 42, wherein the carrier comprises particulate material.

45. The method of claim 42, wherein absorption of the non-tobacco aerosol forming material by the carrier is sufficient to produce a free flowing substrate.

46. The method of claim 43, wherein the carrier comprises particulate material and wherein absorption of the non-tobacco aerosol forming material by the carrier is sufficient to produce a free-flowing substrate.

47. The method of claim 46, wherein the tobacco flavor material is selected from the group of comminuted tobacco, tobacco extract, spray dried tobacco extract or mixtures thereof.

48. The method of claim 46, wherein the non-tobacco aerosol forming material is selected from the group of glycerin, triethylene glycol, propylene glycol or mixtures thereof.

49. The method of claim 46, wherein the carrier is selected from the group consisting of carbon, alumina, silica, ceramic, vermiculite, clay, or mixtures thereof.