AU525910B2 - Puffing tobacco leaves - Google Patents

Description

Patents Act

APPLICATIN FOR A PA!

449 61 M' Insert kULL names)o Ir/We PHlLIP MORRIS INCORPORATED applicant(sf)

0Insert FULL address(eb.) of of (c) aplicant(s) 100 Pi'rk Avenue, New York, New York 10017,. Uiitd States of America

.iereby apply for the grant of a Patent for an invention entitled Insert TITLE (d) of invention NOVEL TOBACCO PRODUCT AND IM4PROVED PROCESS FOR~f MANX1S ION OF TOBACCO

Insert OR "complete" "provisional' which is described in the accompanying complete specification.

(Note,~ The. following paragraphapplies only to Convention applications)

This application is a Convention application based on the b.dsic application(s) for a patent or similar protection Mdentified VLy number, country, and filing date as follows: Inseri number, country and -NI~ng date for Serial Nos: 8919468 and 891,290 the/or EACH basic application United States of America both filed o. March 29, 1978

-SlA

Address for Service- PHILLIPS ORMONDE AND F~~R~ Patent arid Trade Mi~rk Attorneys 367 Collins Street Melbourne, Australia 3000

Insert DATE of Orignin Dated W 1 'ebruary 1979

Signatuire of PHILIP MORRIS INCORPORATED

gesadnote')

Corporate sabil if any Note: K'o legalization or otuwr wltnum Vice President X~oquirsd

PIOILLIPS ORMONDE AND FITZPATRICK Patent and Trade Mark Attorneys 367 Collis Street Molbour=, Australia

Amluk ."Sa

Patents Act. I

DECLARATION FOR A PATENT APPLICATION (NSThtUCTONS sert "Convention- applicable In support of the convention app~ic ation mae- by isert. FULL namne(s) applicant(s) 'PHILIP MORRIS INCORPORATED 44 961 /79 sert "of add'cion- (hereinafter called "applicant(s)") for a patent (c) for an applicable isert TITLE of invention entitled (d) vention NOVEL TOBACCO PRODUCT AND IMPROVED PROCESS FOR THE EXPANSION OF TOBACCO sert FULL namners) NDddrvss(es) of 11(e) Helmut Richard Rea Wakeham Vice President of !clarant(s) cc headnole*j Philip Morris Incorporated of 100 Park Avenme, New York, New York 10017, United States of America

do solemnly and sincerely declare as follows:

,or, in the case of an application by a body corporate) 1. 1 am/WVe-nre authorized to make this declaration on behalf of the applicant(s). ii- 4 -the- etue 4 FelIir.e~e sft*~l-@f-th44akn(" (or, where the applicant(s) is/are not the actual inventor(s)) ert FULL rmen(s) 4D addressI of 2. ROGER Z. DE LA BURDE of Windsor, P.O.Box 168, Powhaten, Virginia, United States of America; PATRICK E. AUMENT of 4600 Oaklawn Boulevard, Hopewell, Virginia, United States of America; and FRANCIS V. UTSCH of 12316 Windsor Road, Chester, Virginia,. United States of America .cite howy ap 1li- s/are the actual inventor(s) of the itivention and the facts upon which the applicant(s) nt(s) derivef le from actual is/are entitled to make the applicati.-in .re as follows: ventor(s) ce headnote**) (g)

Applicant is the assignee of the invention from the actual inventors.

(Note: Paragraphs3 and 4 apply only to Convention applications) ivet country. ng date, and 3. The basic application(s) for patent or similar protection on which the application is based isic applicant(s) rthe Ior EACH *i/are identified by country, filing date, and basic applicant(s) as follows: sic application United States of America March 29, 1978 Roger Z. de la Bur.. AUSITRALIAN Patrick E. Aument Francis V. Utsch -9 MAR 1979 PATiENT OFFICE

4. The basic application(s) referx-ed to in paragraph 3 hereof \Wewere the first application(s) made in a Convention country in respect of the invention the subject of the application. ,sert PLACE of gning scrt DATE of vning Declaed at Richmond, Virginia, USA Dated 12. February 1979 ognature(s) of r-By ~e&

II Lilaranlfs)

N4o legalization or witnecs required Declarant To-, The Commissioner of Patents j

(12) AUSTRALIAN PATENT ABRIDGMENT (19) AU (11) AU-B-44 961/79

(54) PROChSS FOR EXPANDING TOBACCO (71) PHILIP IlRRIS INCORPORATED (21) 44 961/79 525 910 (22) 9.3 79 (24) 29.3..8 (31) 891468 (32) 29.3.78 (33) US 891290 29.3.78 US

(43) 4.10.79 (44) 9.12.82 (51)2 A24B 3/18 (72) ROGER Z. DE LA BURDE, PATRICK E. AUMENT AND FRANCIS V. UTSCH

(74) PO (56) 38 437/78 A24B 3/18 74 234/74 496 284 A24B 3/18, 15/00

(57) Claim 1. A process for expanding tobacco to achieve at least about 50 per cent increase in cylinder volume, comprising the steps of: contacting tobacco with carbo., dioxide gas at a pressure of at least 250 psig and at sufficient temperature that substantially all of the carbon dioxide is maintained in gaseous form, for a time sufficient to impregnate the tobacco with carbon dioxide gas, (ii) decreasing the pressure, and (iii) thereafter heating the impregnated tobacco under conditions effective to liberate the carbon dioxide therein so as to cause expansion of the tobacco.

Claim 2. A process according to claim 1 wherein the gaseous carbon dioxide and tobacco system in step is cooled to a temperature close to the saturation temperature of carbon dioxide but not lower than -230C.

/2

D1, D2 AND D3 46* 1 v h

11) AU-B-44 961/79 2

Claim 10. A tobacco product prepared by the process according to any one of the preceding claims comprising at least 1 part by i."-Tht of gaseous carbon dioxide per 100 parts by weight of toba~eo.

*116/62/9

rL:J

367 (2OlMS btreCT, Meilboupie, Australia

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AU 42591io Patents Act

COMPLETE SPECIE (O1iGINAL)

44 9 61n/79 It. Class Applicalbon Number: Lodged:

Complete Specification Lodged: Accepted,; Published: Priority: 1979 -9 MAvtf%

Related Art:

k.PPLICANT'SREF.: 582-884A/B Australia Name(s) of Applicant(s): PHILIP MORRIS INCORPORATED

Address(es) or Applicant(s): 100 Park Avenue, NewYork, N.Y. 10017, UN~ITED STATES OF AMERICA

Actue2 lnvernori): Roger Z. de la Burde Patrick E. Aument Francis V. Utsch

Address for Service is: f,*HILLIPS, ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Coffins Street Melbourne, Australia, 3000 Complete Speciication for the Invention entitled:

NOV19L TOBACZO0 PRODUCT AND IMPROVED PROCESS FOR THE &APANSION OF TOBACCO

The following st~atet Is a Wl debcriptioni of this invendioii, 1xicluding the best method of performing It known to applicant(s): rm)By Z7--J^C N o lega lizatio n o r m L Switness required Declarant Declarant To: The Commissioner of Patents

-T.

Various processes have been proposed for expanding tobacco.

For example, tobacco has been contacted with a gas under same-

what greater than atmospheric pressure, followed by a release

of the pressure, whereby the tobacco cells are expanded to in-

crease the volume of the treated tobacco. Other methods

which have been employed or suggested have included the treat-

ment of tobacco with various liquids, such as water or re-

latively volatile organic liquids, to impregnate the tobacco

with the same, after which the liquids are driven off to ex-

pand the tobacco. Additional methods which have been suggested

have included the treatment of tobacco with solid materialc

which, when heated, decompose to produce gases which serve to

expand the tobacco. Other methods include the treatment of

tobacco with gas-containing liquids, such as carbon dioxide-

containing water, under pressure to incorporate the. gas in the

tobacco and when the tobacco impregnated therewith is heated

or the pressure thereon is reduced to thereby expand the

tobacco, Additional techniques have been developed for expand-

ing tobacco which involve the treatment of tobacco with gases

which react to form solid chemical reaction products within

the tobacco, which solid reaction products may then decompose

by heat to produce gases within the tobacco which cause expan-

sion of the tobacco upon their release. More specifically:

A patent to Wilford J. Hawkins, U.S. patent 1,789,435,

granted in 1931, describes a method and apparatus for expand-

ing the volume of tobacco in order to make up the loss of weight eased in curing tobacco leaf. .To accomplih this object, the cured and conditioned tobacco is contacted with a

Sgas, which may be air, carbon dioxide or steam under about

-4 pounds of pressure and the pressure is then relieved, whereby

Sthe tobacco tends to expand. The patent states that the

volume of the tobacco may, by that process, be increased to

the extent of about 5

An alien property custodian document No. 304,214 to

Joachim Bohme, dated 1943, indicates that tobacco csn be ex-

10 panded using a high-frequency generator but that there are

limitations to the degree of expansion which can be achieved

o~without affecting the quality of the tobacco.

A patent to Frank J. Sowa, U.S. Patent 2,596,183, granted

in 1952, sets forth a method for increasing the volume of

shredded tobacco by adding additional wate; to the tobacco to

cause the tobacco to swell and thereafter heating the moisture

containing tobacco, whereby the moisture evaporates and the

resulting moisture vapor causes expansion of the tobacco.

A series of patents to Roger de la Burde, U.S. Patents

3,409,022, 3,409,023, 3,409,027 and 3,409,028, granted in

1968, relate to various processes for enhancing the utility

of tobacco stems for use in smoking products by subjecting the

stems to expansion operations utilizing various types of heat treatment or microwave energy.

A p/atent to John D. Hind, U.S. Patent 3,425,425, granted

in 1969, which is assigned to the same assignee as the assignee of the present invention, relates to the use of

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~cl~R"sRa~Frma~n~~-~m "C-l-T3R:l' L~i;i i: 1-~1! I

carbohydrates to improve the puffing of tobacco stems. In

that process, tobacco stems are soaked in an aqueous solution

of carbohydrates and then heated to puff the stems. The car-

bohydrate solution may also contain organic acids and/or

certain salts which are used to improve the flavor and Ssmoking qualities of the stems.

A publication in the "Tobacco Reporter" of November 1969

by P. S. Meyer describes and summarizes tobacco puffing or ex-

pansion procedures or investigations for expanding and manipu- lating tobacco for purposes of reducing costs and also as the

Smeans for reducing the "tar" content by reduction in the de-

livery of smoke. Mention is made in this publication of

puffing tobacco by different procedures including the use of

halogenated hydrocarbons, low pressure or vacuum operation,

or high pressure steam treatment that causes leaf expansion

from inside the cell when outside pressure is suddenly released.

Mention is also made in this publication of freeze-drying

tobacco which can also be employed to obtain an increase in volume.

Since the above-mentioned "Tobacco Reporter" article

was published, a number of tobacco expansion techniques, in-

cluding some of the techniques described in the article, have been described in patents and/or published patent applications.

For example, U.S. Patent 3,524,452 to Glenn P. Moser et al and

U.S. Patent 3,524,451 to James D. Frederickson, both issued in

1970, relate to the expansion of tobacco using a volatile organic liquid, such as a halogenated hydrocarbon.

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~efi~Z~B~L rrr-A 7 WR

U.S. Patent 3,734,104 to William M. Buchanan et al.

which is assigned to the same assignee as the assignee of the

present invention, issued in 1973, relates vo a particular process for the expansion of tobacco stems. 4 SU.S. Patent 3,710,802 to William H. Johnson, issued in

S1973 and British Specificrtion 1,293,735 to American Brands,

Inc., published in 1972, both relate to freeze-drying methods

for expanding tobacco.

South African applications 70/8291 and 70/8282 to R. J.

Reynolds Tobacco Company, both filed in 1970, relae to

tobacco expansion employing chemical compounds which decompose

to form a gas or with inert solutions of a gas under pressure

to maintain the gas in solution until it impregnates the

tobacco.

A patent to Robert G. Armstrong, U.S. Patent 3,771,533,

issued in 1973, which is assigned to the same assignee as the assignee of the present invention, involves a treatment of tobacco with carbon dioxide and ammonia gases, whereby the

tobacco is saturated with these gases and ammonium carbonate

is formed in situ. The ammonium carbonate is thereafter de-

composed by heat to release the gases within the tobacco

cells and to cause expansion of the tobacco.

Despite all of the above-described advances in the art,

no completely satisfactory process has been found. The dif-

ficulty with the various earlier suggestions for expanding

tobacco is that, in many cases, the volume is only slightly

or at best only moderately increased. For example,'freeze- drying operations have the disadvantages of requiring elabor- f the fog ate and exeisive equipment and very substantial operating er cests. With respect to the teaching of using heat energy, in ei infrared or radiant microwave energy to expand tobacco stems, in V-4 from 10 the difficulty is that while stems respond to these heating nds, necti c0 procedures, tobacco leaf has not generally a found to re- thods for t spond effectively to this type of process.

The use of special expanding agents, for example, halo- to ov n

genated hydrocarbons, such as are mentioned in the Meyer pub- LI r10 1 LI prior lication for expanding tobacco, is also not completely satis- tompose 10 carb factory, because some of the materials employed are not al- !ssure 110 I 1 (LL corr a'"~1 ways desired as additives. Furthermore, the introduction, in Burd considerable concentration, of materials which are foreign to assi tobacco presents the problem of removing the expansion agent '533, InB after the treatment has been completed in order to avoid is the LI be 1" C

affecting aroma and other properties of the smoke due to ex- of the traneous substances used or developed from the combustion of :he 1'l 00 LI diox *I II the treated tobncco. ma8te *310 diox" The use of carbonated water has also not been found to LI 8 1 de- 110 L tba be effective, coa.v While the method employing aimonia and carbon dioxide the gases is an improvement over the earlier described methods, art, wher it is not completely satisfactory under some circumstances dif- pans in that undesired deposition of salts can result during the Ing process. itly abou Carbon dioxide has been used in the, food industry as a .ze- curb coolant and, more recently, has been suggested as an extractant h6ld

where it is maintained at a pressure of from about 215 to 305 i AF Cm 2Q to -160C. The carbon dioxide

9 1r W- w rT r- r r-.

for food flavors. It has also been described in German Offen-

iegungaschrift 2,142,205 (Anmeldetag: 23 August 1971) for use,

in either gaseous or liquid form, to extract aromatic materials

from tobacco. However, there has been no suggestion, in con- nection with these uses, of the use of gaseous carbon dioxide Ob for the expansion of these materials. SA process e-ploying liquid carbon dioxide has been found

to overcome many of the disadvantage 6T tht above-mentioned :prior art processes. The expansio of tobacco, ading liquid

carbon dioxide is described in Belgian Patent 821,56 1 which corresponds to U.S. Application Serial No. 441,767 to de la lt Burde and Aument (two of the present co-inventors) and assigned to the same assignee as the present application and

In Belgian Patent 825,133 to Airco, Inc. This process may be described as a process for expanding tobacco comprising

the steps of contacting the tobacco with liquid carbon o adioxide to impregnate the tobacco with the liquid carbon

dioxide, subjecting the liquid carbon dioxide-impregnated

o" :tobacco to conditions such that the liquid carbon dioxide is co.tverted to solid carbon dioxide and thereafter subjecting

the solid carbon dioxide-containing tobacco to conditions

whereby the solid carbon dioxide is vaporized to cause ex-

pansion of the tobacco.

In our earlier work with gaseous C02 at pressures of about 100 psia, we had found that only minute amounts of carbon dioxide gas could be incorporated in the tobacco and

held there sufficiently long for the tobacco to be heated iffen- and expanded. Thus, we found no substantial improvement over use, the prior art anil aseoull CO2 was believed to be much less :eria ls by eaq effective as an expanding agent than the liquid carbon con- speci -4 dioxide employed in the expansion process of the above-mentioned ,xide United States application Serial No. 441,767. We have now Sgaseo found that gaseous carbon dioxide can be introduced into found gaseo tobacco in a manner whereby the gaseous carbon xide remains >ned a when in the tobacco in an amount of one per cent or more to form a Lquid prove product which can then be expanded. Unexpectedly superior aich which 10 results and advantages can be achieved by employing gaseous la gener CO2 in the manner set forth in the present specification. The

0,3 present process may be described as follows: A process for and fina expanding tobacco to achieve at least about 50 per cent flus may increase in cylinder volume, comprising the steps of ng and impregnating tobacco with gaseous carbon dioxide under a on gaug Spressure of at least about 250 psig and at sufficient tempera- ably ture that substantially all of the carbon dioxide is maintain- unde mated ed in gaseous form, decreasing the pressure on the carbon diox e is S dio.ide-impregnated tobacco and heating the impregnated jecting tobacco under conditions effective to liberate the carbon The

dioxide therein so as to cause expansion of the tobacco. The 20 sec K- present invention also relates to an improvement in that phe process and have found that gaseous carbon dioxide can be in- tai troduced into tobacco in a manner whereby the gaseous carbon bas dioxide remains in the tobacco in an amount as high as three dio: per cent or more to form a product which can then be expanded. ves Unexpectedly superior results and advantages can be achieved in

con

tobatoe should not be exposed to the higher temperature levels, fer t over

!ss by employing gaseous C02 in the manner set forth in the present a gas specification. aentioned a per A novel tobacco product comprises tobacco containing .low pand 9 gaseous carbon dioxide in an amount of at least 1 part of Vd

gaseous carbon dioxide per 100 parts of tobacco. The product, remains the t when rapidly heated is converted to expanded tobacco. An im- form a 4 as by proved process for the expansion of tobacco is also provided ior chamb D which employs carbon dioxide as the expansion agent. Tobacco, L' '3

eous a of ca generally having a moisture content of from about 5 to about ftac~

in, The O to us 35% by weight, is placed in a pressure vessel or similar con- ftn

;s for 10 be ca finable space. Carbon dioxide gas may be passed through to the C flush the vessel. Carbon dioxide pressure is then inc-eased ferab and brought to a value of from about 250 pounds per square inch ider a is no gauge (psig) to about 1057 psig or even higher, and prefer- :empera- cooli ably to about 400 to 800 psig. The tobacco is maintained lintain- dioxi under such a pressure under conditions whereby the carbon carbon stant dioxide is substantially gaseous for from about 1/4 to about tated carb 30 minutes, to impregnate the tobacco with carbon dioxide. tem, The pressure is then reduced in a period of from 1 to 800 i nn b

The tabs 20 seconds, preferably 10 to 120 seconds, preferably to atmos- It 20 ent pheric pressure, to produce a product comprising tobacco con- be in- less taining at least 17. by weight of gaseous carbon dioxide, .arbon cant based n the weight of tobacco. The resulting gaseous carbon three at t dioxide-containing tobacco may then be heated in the same cpanded. out vessel but is preferably rapidly transferred, preferably with- iL'2v'ed' diox in a few minutes, to a separate zone where it is subjected to tbr conditions of temperature and pressure, as by rapid heating in syst I I

for the cab. dioxide-tobacco system, with line I-I-I11 ttm a gas at 100 to 370C and at or near atmospheric pressure for a period of from about 1 seend to about 10 minutes, to ex- pad the tdbacco.

An improvement on the above-described invention wnerein

Z the tobacce/CO 2 system is cooled during or after pressurization, as by circulation of a cooling agent through the jacket of the

chamber, to a temperature close to the saturation tenperature

of carbon dioxide but not lower than -23°C. As an alternative

to using a cooling jacket in the improved process CO2 gas can be caused to flow through the system by venting a portion of

the CO 2 gas either during or following pressurization, pre-

ferably while maintaining an infeed of CO 2 gas such that there

is not a loss in the system pressure due to the venting. With

cooling, the resulting conditions are such that the carbon

dioxide at the prevailing temperature and pressure remains sub-

stantially in the gaseous state, but further such that the

carbon dioxide, upon rapid reduction of pressure upon the sys-

tem, is converted partially to a condensed state within the

tobacco. Such conditions may be defined as such that the

enthalpy of the carbon dioxide is kept at a value which is

less than about 140 BTU per Ibm. By this means a signifi-

cantly greater residue of carbon dioxide remains in the tobacco

at the beginning of the expansion step, than is the case with- out the cooling before pressure release, wherein the carbon

dioxide, at higher enthalpy, remains primarily in the gas phase

throughout. A further method of reducing the enthalpy of the

system thereby causing an increased retention of carbon dioxide

i ~Yuurils~,,arra4iP~~,,,;,,~ i~molveesadulation if additional q~inticies of CO2 gas during This vept-ing there.by causing additional sweeping of CO2 gas to flow f or expa., througit the -system. rein ly inexpem in connection~ with the present invention, if desired, nation, '0 expansio the retention of carbon dioxide in the tobacco can be increased f the an expandE by pre-t olinv_ or pre-freezing ^,he tobacco prior to the impreg- ture and incre nation cycle to cause a reduction in the system enthalpy. A ative still further method of increasing the retention of carbon can c e, S8 c cup dioxide in the tobacco involves "pre-snowing" the tdbAicco with of cowtent o', finely divided solid carbon dioxide (dry ice) prior to the im- or sxdA a pregnation cycle which accomplishes both a pre-cooling of the there f lusheki w tobacco and serves as an additional source for providing With a Ithough carbon dioxide to the tobacco; applied in prover amounts of 'i i$ Sed from about 5-507% by weight of the tobacco, at least a portion Ls sub- is, itftod of the dry ice will be incorporated into the tobacco during t rodue4:io the pressurization cycle and by varying the amount of dry ice ~,kn th ye app~lIed, a method of increasing and controlling the amount of he carbon dioxide retained by the tobacco becomes possible. When The re -i such methods are involved, the tobaccof CO2 system may be main- gacieous p~ tained for 1/4 to 30 minutes during the impregnation step, faMi4,1 where.the pressure is at lwets 250 psig, to impregnate the obacco viepr tobacco with carbon dioxide. The pressure is then reduced, in with- a pexiod uf 1 to 800 seconds, preferably 10 to 120 seconds and on preferably but not necessarily to atmospheric pressure. The phase tobacco is then rapidly transferred to a zone where it is t'oe~ the subjected to conditions of temperature and pressure, as by dioxide rapid heating iv a gas at 100 to 3700C and at or near atmos- pheric pressure for one second to 10 minutes to expand the tobaccc, imniotin is show. Tobacco at about 127. OV in the form of

This invention relates broadly to An improved process for expat~ing tobacco employing a readily-available, relative- l.y inexpensive, non-ceombustible, inoffensive, and non-toxic expansion agent and more particularly, to the production of ased an expanded tobacco product of substantially reduced density mreg- and increased filling power. The improved process employo', A carhon dioxide as the expansion agent. In general, the. i,-o-

ress compiris,,,s plac~ugiS aco, prefenly hbvizag a oistivre eith cowtent o C frcet about 5 to about 35%, by oweight, in a l'essel im- or skAlar confinablie space; the vessel or space may then be the flushed with gaseous CO 2 to reao've most of tb1t associated air,

although this is not essential to the invention. The vessel f ,41-sed except for an inlet port, and carbon dioxide gasi ion is Ittroduced and the pressure .ncrease(!, by continued gas3 in- 9 troduction cr heating or both, under car~V! 7ons whereby tae CC2 ice 1,n the vessel remains prim!arily in the tan state to a final of presware of at least 250 psig, preferably 400 to 800 pigig. When The ze-ivired temperattwaf maintain theC.02 in a substatlally main- gataeous state at a given pressure m~y be determined readily by

i famLUiar with the use of phase diagrams or critical tables.

7A,41le pressures as high as 900 psig might be economically em- 1. in played~, in~i a pressure of about 1057 would be acceptable, and tbhere is no, known upper 'Limit to the useful impregnation pres- .he sur'e 4aa,,,,e cther than that imposed V- the capab.'lities of -the oipenrt available. However, operation below the critical

toa~t~tre Is preferred for ease of control. The tobacco tvbe mainitained under these improgzating conditions from tobacco

The! t a~p~rturs at uhich the impregnated tobacco is

%J

about 1/4 to 30 minutes, the longer times beiaig "I C ieral

applicable to lower pressu1re operation. ReZerence to the

pressure-enthalpy diagram for 0Co 2 as set forth in Figure 1 of

the drawing will be of help in selecting des-ir'ad conditions.

After the iinpregnation step, the gas pressure is reduced by

venting. The final pressure may be atmospheric or some pres- sure near that to be employed in the expansion step, but pre-

Lerably the former. The time of pressure Yr-duction is from

1 to about COO seconds. The gaseous idioxide-containing

tobaco is then transferred ;o a zone re it is subjected to

conditions whereby the carbon, dioxide is remo-red to expand

the tobacco. The transfer of the carbon dioxide-containing

tobacco to the heating or expansion zone should preferably be effecte'd within as short a time as possib'., preferably within

about five minutes, and most preferably within about two

minutes. As an alternative to rapid transfer, if desired, the etzbon dioxide-containing tobacco may be stored in an

insul~ated biilker or chilled or otherwise maintained in a re-

latively cool condition. The heating or expansion step prefer- abl- involves exposing the~ carbon dioxide-contaf-ing tobacco

to rapid heating at a temperature of about 100 to 370*C for a

period of time of from about 1 second to 10 minutes and sub-

stintially atmospheric pressure.

In accurdance with improvement in the present invention,

the impre~iation step is modified, as will be set forth in de- tail later in this specification. After th~e impregnation~ step, the gas prossure is reduL 4 by -renting. The fini1 pressure may

CO2 contained therein. The imprcegtedmteil

4 the% within about 5 rninfttei time, exposed to heating in 4icj diamter tobacco expansion tower by contact with suparhe~ted steam at 2880C and a velocity of 140 ft/sec for &bout 4 seconds. The product exiting the exp~naion tower had be atmbspheric or some pressure near that to be employed it the expansion step, but preferably the former. The time of pess:re reduction is from 1 to about 800 seconds. The gaseous carbon dioxide-containing tobacco is then transferred

Sto a zoac where it is subjected to conditions whereby the

carbon dioxide is removed to expand the tobacco. The transfer

of the carbon dioxide-containing tobacco to the heating or

expansion zone should preferably be effected within as short

a time as possible, preferably within about five minutes, and

most preferably within about two minutes. As an alternative

to rapid transfer, if desired, the carbon dioxide-containing

tobacco may be stored in an insulated bulker or chilled or

otherwise maintained in a relatively cool condition. The heat-

ing ov expansion step preferably involves exposing the carbon

dioxide-containing tobacco to rapid heating at a temperature

of about 100 to 370°C for a period of time of from about

1 second to 10 minutes and substantially atmospheric pressure.

To cary out the process of the invention, one may treat

either whole cured tobacco leaf, tobacco .n cut or chopped

form, or selected parts of tobacco, such as tobacco stems or

may be reconstituted tobacco. In comminuted form, the

tobacco to be treated may have a particle size of from about

to about 100 mesh, but is preferably not saaler than

about 30 mesh.

The tobacco may contain the natural moisture content

of tobacco and may contain from about 5 to about 35% by weight

moisture. It is preferred, however, for best results that the

EM"MLE 3

A series of bright tobacco samples were.treated as in

Example 1 under conditions where gaseous CO 2 and substantially

no liquid or solid CO2 would be formed. The hold time was Z 1J l.J .A fant1 rpiiilt-q *VA cherwn 4nI Tahlp TT tOba have at least about 8% moisture (by weight) and no more than about 22% (by weight) moisture. As uset herein, moisture may be considered equivalent to oven volatiles

(0O) since not more than about 0.9% of the tobacco weight is volatiles other than water. The procedure for determining

oven volatiles is set forth later in this specification.

The tobacco will generally be placed in a pressure vessel which will be more fully described hereinafter. For example, it may be placed in a wire cage or on a platform

positioned within the vessel. C-

The tobacco-containing pressure vessel may be then

purged with carbon dioxide gas. The benefits of purging are

the removal of gases that might interfere with a carbon dio-

xide recovery process and/or that might interfere with full penetration of the gaseous carbon dioxide. As an alternative

Sto purging with carbon dioxide gas, the vessel may be evacuated

prior to introduction of the carbon dioxide gas.

Either with or without a preliminary purging or evacua-

tion of the vessel, carbon dioxide gas is fed to the vessel

under conditions whereby the carbon dioxide gas pressure in

the vessel is increased under conditions whereby the tobacco

in the vessel is preferably at a temperature of from about

to about 60*C, and the pressure in the vessel is above about 250 psig, preferably about 400 to 800 psig. The tobacco

is jEintained under conditions whereby the crrbon dioxide is

at a pressure above about 250 psig apa is under conditions above and to the right of the saturated vapor line of Figure 1

tabie XII

ijier Expansion with Gaseous CO'

Tt 6 Z 8 9 10 11

no 1L- 13.6 10.3 16.1 13.2 13,3 g it known to

-2-

no of the drawing from.a1period of from about 15 Seconds to fl' ,i c in, about 30 mivutes. The pressure is then reduced over a period gase es of from 1 to about 800 seconds, preferably 10 to 120 seconds, may 1 ht is such that the temperature at no point drops below the saturm- in t ing tion temperature for carbon dioxide at the simultaneous pres- of pi

sure, and the tobacco is brought to a temperature below about 0C, and atmospheric pressure or the pressure at which the under

expansion step is to be carried out. not I

In the improvement on this invention, the tobacco/CO part 2

system during the impregnation step is cooled, as for example, By t

by circulation of a refrigerant through the jacket of the *c 10 per Lng are 4

vessel containing the system, to reduce the enthalpy of the C 4 a toba a dio- a4

carbon dioxide below about 140 BTU/lbm, preferably while the iI. exa full 'lap pressure is maintained relatively constant by admission of as h rna tive additional carbon dioxide gas. The cooling is limited so that the evacuated the carbon dioxide is not condensed to any significant degree the 9 (7 1(7 and is not cooled to a temperature lower than -230 C. The 4' K abso evacua a) 0'

system 1s maintained under these impregnating conditions from 4(7 ir that essel a (p4

about I/4 to 30 minutes, the longer times being in general them re in applicable to lower pressure operation. Reference to the afore- or obacco wwentiontd phase diagram or critical tables for carbon dioxide 20 ma bout will be of help in selecting desired conditions. The presslir,4- the bove teuperatyire relationship is preferably maintained to keep the as tobacco carbon dioxide gas at or near the saturation point. It is be- pre :ide is lUeved that when the conditions are close to or at saturation, kee ions thhe absorption/adsorption characteristics of gaseous Co2 are tha Figure 1 vesatly enhanced. This results in improved retention of Sor

of Pfie CO2 gas in the impregnator were found to correspond to Tsti

an enthalpy value of about 130 BTII/lb. of C 2 gas. Although C0 2 Prodmu n nA na*ifn nrobablv ozcurred within the vessel, the New*d gaseous CO2 The final pressure, when the pressure is reduced, may be atvespheric or some pressure near that to be employed in the expansion step, but is preferably atmospheric. The time of pressure reduction may be from about 1 to about 800 seconds.

It has been found that after the impregnation step,

Sunder conditions where the cooling of the improved process is

Snot employed, a product will be formed having at least one

part of carbon dioxide gas per one hundred parts of tobacco. By this is meant that at least one part of carbon dioxide gas,

per one hundred parts of tobacco, will be associated with the tobacco in some manrer, chemically and/or physically, for t.

example by being absorbed by the tobacco. The product may have

as high ar three parts or more of gaseous carbon dioxide when

the process is so conducted. This has been found to occur in

the absence of added adsorbents or the like. Adsorbents,

absorbents or the like may be present; however, it is preferred

o that they not be present since the process is effective without them and they might introduce undesired elements into the smoke

or might not release the carbon dioxide in a totally effective manner. It has been found that after the impregnation step,

the tobacco may contain even greater amounts of carbon dioxide, as high as 3 parts (per hundred of tobacco) or more. The

pressure-temperature relationship is preferably maintained to

keep the gas at or near the saturation point. It is believed

that when the conditions are close to or at saturation, the ab-

sorption/adsorption characteristics of gaseous C02 are greatly

nihanced. This results in improved retention of gaseous CO2

13 14

The final pressure, when pressure is reduced, may be atmos-

pheric or some pressure near that to be employed in the expan-

sion step, but is preferably atmospheric. The time of pressure

Sreduction may be from about 1 to about 800 seconds.

SWe have found that after the impregnation step, under Sconditions where the cooling of the improvement in the present

invention is employed, a product will be formed which may have

as high as three parts or more of gaseous carbon dioxide, per

one hundred parts of tobacco. By this is meant that at least

three parts of cazbon dioxide gas, per one hundred parts of

S tobacco, will be associated with the tobacco in some manner, chemically and/or physically, for example, by being absorbed

by the tobacco. I have found this to occur in the absence of

added adsorbents or the like. Adsorbents, absorbe,'ts or the

like may be present; however, it is preferred that they not be

present since the process is effective without them and they

might introduce undesired elements into the smoke o. might not release the carbon dioxide in a totally effective manner.

The tobacco, after the impregnation step, may then be transported to a zone where it is subjected to conditions such

that the carbon dioxide is removed and the tobacco is expanded,

preferably by exposure to rapid heating at 100 to 370 0 C for 1

second to 10 minutes and substantially atmospheric pressure.

A description of the improvement on the presently claimed

process will be described below, said improvement relating

specifically to the impregnation step.

To carry out the improvement on the present proce l one -Ar tnhacco leaf. tobacco in cut or chopped form, or selected parts of tobacco, such as tobacco stems br may be reconstituted tobacco. In comminuted form, the tobacco to be treated may have a particle size of from about 10 to about 100 mesh but is preferably not smaller than about 30 mesh.

The tobacco may contain the natural moisture content of

tobacco and may contain from about 5 to about 35% by weight

moisture. It is preferred, however, for best results that

the tobacco have at least about 87. moisture (by weight) and 6 10 no more than about 22% (by weight) moisture. As used herein,

moisture may be considered equivalent to oven volatiles (OV)

since not more than about 0.97%of tobacco weight is volatile

other than water. Oven volatiles determination is a simple

measurement of weight loss on exposure in a circulating air

oven for 3 hours at 100*C.

The tobacco will generally be placed in a pressure vessel

which will be more fully described hereinafter. For example,

it may be placed in a wire cage or on a platform positioned

within the vessel.

The tobacco-containing pressure vessel may be then purged

with carbon dioxide gas. The benefits of purging are the re-

moval of gases that might interfere with a carbon dioxide re-

covery process and/or that might interfere with full penetra-

tion of the gaseous carbon dioxide. As an alternative to

purging with carbon dioxide gas, the vessel may be evacuated

prior to introduction of the carbon dioxide gas.

The carbon dioxide which is employed in the process of

this invention will generally be obtained from a storage vessel

Table V Series #1 SrioP A9 where it is maintained at a pressure of from about 215 to 305 paig and temperatures of from -29 to -16°C. The carbon dioxide may be introduced into the pressure vessel at 215 to 320 psig and -29 to -14°C, but is preferably brought, by suitable means,

0 C, and a pressure above 250 psig 0) to a temperature above -23

Sbefore being introduced into the pressure vessel. Either with or without a preliminary purging or evacua-

tion of the vessel, carbon dioxide gas is fed to the vessel

t( a under conditions whereby the carboi dioxide gas pressure in S* 10 the vessel is increased under conditions whereby the tobacco in

the vessel is at a temperature of from about -10 to about

and the pressure in the vessel is above about 250 psig, pre- Sferably about 400 to 800 psig. The tobacco/CO 2 system is

cooled in such a way that the CO2 enthalpy is brought below

about 140 BTU/lbn but the gas is preferably not condensed to

any significant degree, while the pressure is, preferably, held

substantially constant by admission of additional gas, and the

system is maintained at these conditions from about 15 seconds

e to about 30 minutes. The pressure is then reduced over a period

of from about 1 to about 800 seconds, whereby the tobacco is

brought to a temperature below 100C, and atmospheric pressure or

the pressure at which the expansion step is tt> be carried out.

The resulting carbon dioxide-eated tobacco may then be

rapidly transported, as described eatlier in this specification

to a zone where it is B d exposed to exp conditions by sub-

jecting it to heat or the equivalent in order to remove the

carbon dioxide from the tobacco. This may comprise the use of

Wk"WW"&WW"W NOW an a carbon dioxide gas could be incorporated in the tobacco and tractant held there sufficiently long for the tobacco to be heated hot surfaces, or a stream of hot air, a mixture of gases and tobaC e.g., steam, or exposure to other energy sources, such as microwave exorgy or infrared radiation. It has been found that the use of a gas composition comprising at least 50. (by weight) of is to V-

Paten steam, and preferably above 807. (by weight) of steam, provides 'i4

A convenient means of ex- never particularly satisfactory results. the r panding the carbon dioxide-ontaining tobacco is to place it or heati to entrain it in a stream of heated gas, such as superheated

steam or to p1ie it ir, a turbulent air stream maintained, for 0 0'

10 dryer 4. 10 example, at a temperature of from about 150to about 2600 C (as 0 a lone U 0r low as 100 0 C and as high as 370'C) for a period of about 1 V1 r., V.

is a second to 10 minutes. The impregnated tobacco may also be U 0

4~ 3 heres '3 heated by being placed on a moving belt and exposed to infrared 43

from heating by exposure in a cyclone dryer, by contact in a tower 43 (U held 03,, about with superheated steam or a mixture of steam and air or the the time like. Any such contacting steps should not raise the tempera- '3 rds V. or sc ture of the atmosphere with which the tobacco is in contact 43 0 C, eriod heat to above about 370 0C and should preferably be from at about 4 U

*01 'S 3 caus C 3' 100 to about 300 0 C, most preferably 150 to 260 0 C when con- V.p

a4 ire or 20 dark ducted at atmospheric pressure. *UI )ut. 43300 4 3 of t As is well known in the processing of any organic matter, i be overheating can cause damage, first to colour, such as undue pans it ion pref darkening and, finally, to the extent of charring. The nec-

essary and sufficient temperature and exposure time for ex- ferrI pansion witbmaut such damage is a funct on of these two variables e of as well as the state of subdivision of the tobacco. Thus, to

avoid undesirable damage in the heating step, the impregnated

Reordered pressure aig) OV% (IV ccv

2.4 54.3 11.9 56.3 2.0 577 11.6 58.2 e) r 5.7 7 11-.7 58.7 tobacco should not be exposed to the higher temperature levels,

370*C, longer than 1 to 2 seconds.

One metihod for causing the expansion of the tobacco cells

is to use the radiation methods described in either U.S.

Patents 3,409,022 or 3,409,027. In this operation, the tobacco 4 ;D never attains a temperature above about 140*C, being cooled by

i the rapid evolution of gases. The presence of steam during

heating assists in obtaining optimum results.

Another system, usually preferred, is to use a dispersion

dryer, for example, one that is supplied either with steam

Salone or in combination with air. An example of such a dryer

is a Proctor Schwartz PB dispersion dryer, usually called

hereafter a tower. The temperature in the dryer may range

from about 120 to 370°C with contact time in the dryer of

about 1 to 10 seconds. In general, a 1 to 6 second contact

time is utilized when the hot gas temperature is 260 to 315*C

S or somewhat higher. As stated before, other known types of

S. heating means may be used as long as they are capable of

causing the impregnated tobacco to expand without excessive

darkening. The presence of a steam atmosphere of 207 or more

of the total hot gas composition aids in obtaining the best ex-

pansion; a high proportion over 807 volume) of steam is

preferred.

The present invention may be further understood by re-

ferrtig to the drawings. In the drawings:

Fig. 1 is a standard phase diagram plotting pressure of

CO2 (in vs temperature (in of the tobacco bed

a vaue my be adj V1lio ed se sV)

The CV value may be adjusted to some specified oven- t' -J.9 '1 .9 A. I

I.

in a few minutes, to a separate zone where it is subjected to

conditions of temperature and pressure, as by rapid heating in

for the carbon dioxide-tobacco system, with line I-II-I11

drawn thereso as an illustration of the system involved here.

Fig. 2 is a standard pressure enthalpy diagram, with

line I-IV drawn thereon to further illustrate the present

invention. T**4 D Fig. 3 is a standard pressure enthalpy diagram, with 0> Sline I-IV drawn thereon to illustrate the process of the

present invention.

As a general illustration of the practice of this inven- tion, reference may be made to Fig. 1. The conditions may,

for example, be such as are represented by line I-II-III on

Fig. 1. For example, the tobacco, at about 12% OV in the form

of cut bright filler, is placed in a pressure vessel capable

of handling the desired pressure, for example, capable of

handling a pressure of 1057 psig. The vessel may be similar

to the impregnation vessel described in U.S. application Serial

No. 441,767, but, in distinction to that apparatus, need have

no means for the handling of liquid C02 The vessel may be

flushed with gaseous CO2 or may be evacuated and is pressured with gaseous CO2 to bring the contents to a condition (at II)

where the pressure is greater than 250 psig and the temperature

is not less than -23°C. The pressure is then released (to III). The conditions of the entire sequence (as shown by line II-II-I)

are such that the carbon dioxide is maintained below and to

the right of the saturated vapor line on Fig. 1. Tr fwnm nf the invention, as may be seen from Fig. 2, 1rn

Ute Qg is present in gaseous form. The vessel may be main-

tained at these conditions for 1/4 to 30 minutes, as illus-

trated by line I-III. The pressure may then be reduced

rapidly, preferably within 10 to 120 seconds, preferably to

atmospheric pressure, as illustrated by line III-IV in Fig. 2. SThe impregnated tobacco then is transferred (preferably 0C bc not necessarily directly) to a rapid heating zone or vessel such as the heating vessel described in U.S. application

Serial No. 441,767 mentioned above or as described earlier in this specification, for example, an expansion tower, micro-

wave chamber, or the like.

The teuverature at which the impregnated tobacco is main-

tained prior to the expansion or rapid heating step will

largely govern how long the CO2 remains in the tobacco in sufficient quantity to cause the desired expansion. If there

is little insulation or means to keep the temperature down,

the transfer should be rapid, preferably less than a few

minutes. An insulated "bulking" container is preferred to

S accomplish the transfer. Supplementary cooling may also be

provided as, for example, by applying crushed or powdered dry ice or by spraying liquid nitrogen on the impregnated tobacco.

The rapid heating causes expansion of the tobacco at a

temperature where the tobacco is pliable and elastic and the tobacco can be expanded without fracture to an approximation

of its green leaf state. A significant and useful degree of

expansion is realized.

Referring to the Fig. 3, an illustration of the present

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1 A a r neRAf for exnandina tobacco to achieve at least invention is shown. Tobacco at about 12% OV in the form of cut bright filler is placed in a pressure vessel. The vessel may be similar to the impregnation vessel described in U.S.

application Serial No.441,767 but, in distinction to that

apparatus, need have no means for the handling of liquid CO2

SThe vessel may be flushed with gaseous CO2 or may be evacuated

and is pressured with CO2 to bring the contents to a conditiLr

wherein the pressure is greater than 250 psia and the tempera-

ture is not less than -23°C, and the enthalpy is at or above

140 BTU/lbm as shown by line I-II in the drawing. The enthalpy

of the CO2 is then reduced by cooling below about 140 BTU/lbm

(but at conditions of temperature and pressure such that the

CO2 is present primarily as gas) as shown by line II-III. The

vessel is maintained at these conditions for 1/4 to 30 minutes.

The pressure is then reduced rapidly, preferably within 10 to

120 seconds, for example, to atmospheric pressure, as illus-

trated by line III-IV.

The impregnated tobacco then is transferred (preferably

but not necessarily directly) to a rapid heating zone or

vessel such as the heating vessel described in U.S. application

Serial No, 441,767, mentioned above, or as described earlier

in this specification, for example, an expansion tower, micro-

wave clhmber, or the like. The rapid heating causes expansion

of the tobacco at a temperature where the tobacco is pliable and elastic and the tobacco can be expanded without fracture

to an approximation of its green leaf state. A significant

and useful degree of expansion is realized.

lr i -i y t~~tquitjrnt~ avt-,Ulable. However, operation below th-je critical

LOS- ~t#;,meatuiLe i.s preferred for ease of control. The tobacco

Le t~acc~ may be maintained under these impregn-ating conditions from

of Jhe t,%rerature at which thie impregna ted tobacco 1.1 ssel maiataimoid prior to the expansion or rapVi 1he,-tn2g step will S. laxfgely govern how long the C02 remsains in the tob~acco in

stffieni,, quantity to cause the desired enpansion. If there CO 2 is little iusulation oiv: mtians to keep the temperature down. ua ted the, tvasf or should be rapid, prefe~rably less than a 'Jew itt, rmivates. An insulated "bulking" container is prefer~red to

tpera- accomplis~h the transfer. Supplementary cooling may also oe ove pro'9idttd as,, for example, by applying crushed or powdered dry tha lPY, 10 ice or by spraying liquid nitrogen on the impregnated tobacco. lb mThe following examples are illustrative: the EXA MPLE I. The A i-pound sample of ccmmercial cased bright tobacco nutes. filler at 12.5% OV was placed in ani at,,c lave- t-e pressure 0 to vessel and was pressurized to 800 psig with C02 gas obtained UIS- from a CO02 supply tank which was maintained at a CO02 pressure

at least slightly abo.ve the desired impregnation pressure. Sb ly The impvegnator system tem~perature was maintained above 30%0

during the pmessure cycle by suplying extra heat to the .ation 20 system,when necessary,to prevent any foratacion of liq~uid or Ler solid 00 2 during the entire proc*.ssing cycle. After a Lcro- minute contact time, the pressure and tempera tuze conditions sibn of the 002 gas the impregnator were found to corresapond to ile ~an enthalpy value of about 142 BTU/lb of (,10 gas. The preseure tre was released by venting in about 30 seconds af r which the tobacco temperature was found to be 2.200. The im~pregnasted

sample had a weight gain of 2.07. which is attributable to the gas pressure is redutid by 'enri-ng. JTle LJ.L2ZL pjLIGaaLL6A. j e gaseouse CO2 containied therein. The impregnated material thee within about 5 minu.tes time, exposed to heating in a 3-1x'~ch diameter tobacco expansion tower by contact with superheated steam at 288%C and a velocity of 140 ft/sec for

:about 4 seconds. The product exiting the expansion tower had CO an OV of The product was equilibrated at standard con-

*r.ditions of 23.9%C and 60%R11 for about 18 hours. The filling

power of the equilibrated product was measured by the standard-

ized cylinder v~olume (CV) test described later in this specifi-

cation as 74 chO g a 11.2% This gave a rorrf.cted CV

(CCV) value at 117% OV of 76 cc/10 g. unexpanded control was found to have a cylinder volume of 36 cc 1 O g. The sample

after processinig, therefore, bad a 111% Increase in filling

power as measured by the CV method, EXAMPLE 2 A series of bright tobacco samples were trea .ed as in

Example 1 under conditions where gaseous 00 2 and substantially

'Kno liquid or solid CO02 would be formed. The tobacco feed OV

wa, varied from 9% to 14.6%. The conditions of each test and

23 the test results are shown in Table I. Where no value is shown

in the Table for a varidble, the value is as in Example 1. Tabl-, I

Filler Expansion -with Gaseous 002 Test 1 2 3 Tobacco Fe,,1 OV 9.07% 10,3% 14.6% ImrgainPressure, psig 800 800 800 C02 T/hmpera~ure Prior to Vent,% 31.7 31.7 32.2 CO Enthalpy Prior to Ve..G ,BTU/lb. 143 143 143 TO .AcoTemup. after Venting, OC -20.0 -22.8 +2.8 %CO2 Retenttion on Tobacco 2.9 2.4 Product OV after Expansion 1.7% 1.87% 3.27%

Reordered Product CV 62 94 74 CV at 11%oYV OV oRererd Produict 11.6 10.3 88 11.3 76 Corrected 66 moisture. It is preferred, however, for best results that the

EXAMPLE 3

A series of bright tobacco samples were.treated as in Example 1 under conditions where gaseous CO2 and substantially

no liquid or solid CO2 would be formed. The hold time was

varied. The conditions and test results are shown in Table II.

Where no value is shown in the Table for a variable, the

value is as in Example 1. Table II

Filler Expansion with Gaseous CO2

Test 3 4

Tobacco Feed OV 14.2% 14.4% 15.3% Impregnation Pressure, psig 800 800 800 Hold Time, Minutes 1 2 CO2 Temperature prior to Vent, OC 58.9 30.0 35.6 CO2 Enthalpy prior to Vent,BTU/lb. 160 142 144 Tobacco Temp. after Venting, OC 8.3 -5.6 4.4 CO2 Retention on Tobacco 2.0 2.6 Product OV after Expansion 2.2% 2.0 3.8 Reordered Product CV 71.2 74.0 76.2 Reordered Product OV 11.1 11.6 11.6 Corrected CV at 11% OV 72 78 Increase in Filling Power 100 117 122

Ex ,ple 4 A series of bright tobacco samples were treated as in

Example 1 at conditions where no liquid or solid CO2 would be

expected to be formed. The impregnation pressure was varied.

The test results are shown in Table III. Where no value is

shown in the Table for a variable, the value is as in Example

1.

-28-

!1

Fille Expas ion with Gaseous O

!rest 7 9 10 11 Tobacco Feed OV 14.5 13.6 10.3 16.1 13.2 13 *3

'-4 Impregna tion Pres- sure, psig 300 400 5010 600 700 goo Rol d Time, Minutes -05 15 15 25 15 q~4 C02 Teperature prior to Vent., -C -11.7 NA 20.6 20.6 19.4 53.9 CO Enthalpy prior lo Vent, BTU/Ilb. 143 A 150 145 142 155

Tobacco Temip. after Venting, 0C -13.9 NA 3.3 -5.6 -16.7 20.6 Product OV after Expansion 2.2 1.9 2.1 2.1 3.4 2.7

ReordererI Product CV 69 66 59 75 74 Reordered Product OV 10.7 11.5 11.*7 11.4 11.5 11.6 Corrected CV at 1',7O oV 66 69 64 79 77 Increase in Filling Power 83 92 78 119 114 81

EXAMPLE

A 1-pound sample of conmmercial cased bright tobacco filler at 11.17. OV v~as placed in an FS-" pressure vessel and

pressurized to 800 psig with CO2 gas as in the procedure of~

Example 1. The impregnation system.I temperature was cooled

by circu4 tirng a cooling solution through a jacket surrounding the impregnation vessel until the CO2 gas in the~ impregnator

was cooled to near its saturation temperature. After a

mzinute contact time, the pressure and temperature conditions

''llin~~'3 13 111'1111

of the CO 2 gas in the impregnator were found to correspond to

an enthalpy value of about 130 BTU/lb. of C02 gas. Although

some C02 condensation probably occurred within the vessel, the

CO2 vas present primarily as a gas. The pressure was released

by venting in about 30 seconds after which the tobacco tempera-

S ture was found to be -37.8 0 C. The impregnated sample had a

S weight gain of about 3.5% attributable to CO2 This impregnated

material was then heated as in Example 1. The product exiting the expansion tower had an OV of The equilibrated pro-

duct had a CV of 90.6 at an OV of 10.8%. This corresponds to

a CCV of 89 or an increase in filling power of 147% over the Sunexpanded control (36 cc/10 g).

EXAMPLE 6

A series of bright tobacco samples were treated as in

Example 5 at conditions where the CO 2 gas would be cooled to

near saturation prior to pressure release at three different

pressures. The conditions and test results are shown in Table SIV. Where no value fs shown in the Table for a variable, the

value is as in Example 1.

Table IV SFiller Expansion with Gaseous C2O Test 12 13 14

Tobacco Feed OV 9.57 10.8 12.1 Impregnation Pressure, psig 800 600 500 Hold Time, Minutes 15 15 CO2 Temperature prior to Vent, °C 19.4 7.2 2.2 CO2 Enthalpy prior to Vent,BTU/lb. 129 139 139 Tobacco Temp. after Venting, OC -38.9 -27.8 -18.3

-li"'Y'~Elli*rl?;.-l~UIL LYI Yll~n~421 PIY-n ir~il~il.YfCii. 111_i LL i r

Test 12 13 14

CO2 Retention on Tobacco 3.7 2.6 2.4 Prodict OV after Expansion 1.37. 1.4 1.9 Reordered Product CV 89 88 71 Reordered Product OV 10.5 10.9 11.9 Corrected CV at 11% 0V 85 87 78 S Increase in Filling Power 136 142 117 -i EXAMPLE 7

qc The procedure of Example 5 was repeated using cased

S burley tobacco. The equilibrated expanded product was found to have a CV of 92.4 at 10.17. 0V or an increase of about 100%

over the unexpanded control.

EXAMPLE 8 The procedure of Example 5 was repeated using a tobacco

blend as normally used in cigarette manufacture. The product was found to have a CV of 78.1 at 11.1% OV or an increase of

about 105% over the unexpanded control.

EXAMPLE 9 A 1-pound sample of cased bright tobacco was processed

as in Example 1 and found to have a CCV of 81. This product was blended at 257% with conventional tobacco blend. Cigarettes

were smoked and found to have a desirable taste and aroma; S firmness of the tobacco rod was acceptable.

EXAMPLE A 13-pound sample of cased bright tobacco was processed as in Example 5. The product was found to have a CCV of 78.

EXAMPLE 11 A 5-pound sample of cased bright tobacco was impregnated as in Example 5 but was then subjected to heating in a static bed using 149'C steam for a 5-minute exposure. The equilibrated product was found to have a CV of w rL -il r'

To carry out the improvement on the present procer e one

cut or may treat either whole cured tobacco leaf, tobacco in

EXAMPLE 12

A series of runs was conducted following the process

of Example 5 and the runs were found to give cylinder volume

results of 80, 80, 80, 79, 84, 78, 79, 78 and 79, respectively.

This gives an average CV of 80 for the 9 trials or an increase to M3 in filling power of 121% over the untreated control.

SEXAMPLE 13 A series of 3 runs was conducted according to the pro-

cess of Example 5, except that the feed tobacco was pre-chilled

to a temperature just below -20*C before the tobacco was con-

tacted with the pressurized CO2 gas. The reordered product

CV results under these circumstances were found to be 92, 92

and 87, respectively. This gave an average increase in filling

power of 151% over the untreated control.

EXAMPLE 14

Two series of runs were conducted in a manner similar

to Example 1. However, conditions were as indicated in Table

V with a ten-minute hold period and the tower conditions were:

3-inch tower at 600*F, with 100% stesio. Series #2 was run

under similar conditions to Series #1.

The results of both series of these runs are given in

Table V together with the results for an unexpanded control

sample and for a control sample which was expanded, without

any CO2 treatment:

-32-

I

Table V Series #1 Series #2 Reordered "Reordered Press. (psig) OV CV/OV CCV OV CV/OV CCV

Control 11.8 36.8/12.6

Exp.control 1.9 64.6/10.9 250 2.5 72.8/10.8 71.2 1.5 73.8/10.8 72.3

300 2.8 76.3/10.8 74.9 1.2 81.4/10.7 78.9

325 2.6 77.2/10.8 75.9 1.2 79.6/10.7 77.5

350 2.3 78.4/11.0 78.4 1.2 77.3/11.2 78.5

375 2.4 80.6/11.1 81.0 1.4 78.7/11.1 79.6

400 2.6 78.5/11.2 79.9 1.4 82.0/11.1 85.6

800 2.8 92.0/11.2 93.3 1.5 97.6/11.1 98.0

It will be seen that pressures of 250 psig through 800

psig provided excellent expansion, compared with the controls.

The following experiments were also conducted:

Experiment 1

The impregnation procedure of Example 11 was repeated

but the impregnated material was simply allowed to warm to room

temperature and was not subjected to tower expansion. The re-

sulting product showed no gain, and perhaps a slight loss, in

CV compared to the untreated cont .1.

Experiment 2

A comparison run of gaseous vs. liquid CO2 impregnation

was conducted in the following manner.

1. Liquid C0 2 Three pounds of cased commercial bright

tobacco filler (OV of 12.7%) was impregnated with liquid C02

at 800 psig, cooled to 19.6 0 C, and held for 15 minutes. There-

after the excess liquid was drained and the pressure was re-

leased. A 23% gain in weight was attributed to CO2 pickup.

77, 3~

The material was somewhat clumped together because of the

large amount of retained C02.

2. Gaseous CO 2 Three pounds of cased commercial

bright tobacco filler (OV of 13.37.) was pressurized with

gaseous CO2 at 800 psig and 19.6°C for 15 minutes. Thereafter r- the pressure was released. A 3% gain in weight was attributed

to CO2 pickup. The material was free-flowing and easy to

handle.

Both samples were processed in a 4-inch diameter

tobacco expansion tower and the samples were equilibrated and

measured for cylinder volume. The samples which utilized the

liquid impregnation was found to have a CCV of 79 and the com-

parable sample impregnated with CO2 gas was found to have a

CCV of 82.

Experiment 3

A series of trials was conducted over an impregna!.on

pressure range of 20, 40, 60, 80, 100, 200, 300, 400, 600 and

800 psig, employing 10-minute contact time, following the

pattern of Example 1, with expansion in the tower with a steam

temperature of 3160C. These samples were run, together with

an unexpanded control and with a control which was not con-

tacted with CO2 with the conditions and the results set forth

in Table VI:

Table VI Reordered Pressure (psig) OV% CVV CCV

Control 13.6 30.8 13.3 33.2 Exp. control 2.9 49.3 12.2 50.1 2.9 55.7 11.8 57.2 pansien withot such damage is a func .on of these two variables 3e of as well as the state of subdivision of the tobacco. Thus, to avoid undesirable damage in the heating step, the impregnated C02

Reordered Presure (Ns) ov% (v CCV 2.4 54,3 11.9 56.3 2.0 57.7 11.6 58.2 2.5 57.7 11.7 58.7 100 2.6 55.7 11.7 56.7 volati eafter 200 2.3 56.4 11.7 57.4 300 2.7 55.0 11.8 56.5 buted 400 1.9 65.9 11.5 68.9 600 1.8 75.9 11.6 80.7 and F V-4 800 1.8 84.4 11.5 88.4 the pa 44: Table VI illustrates that some expansion may be obtain- Y.4 0ven-1 ed at lower pressures, but pressures of about 400 psig may be

d and necessary to achieve product objectives. It will be leee after -d the however, from Example 14, that a pressure of 250 psig can be at te com- effective to produce a satisfactory degree of expansion. ar oven-)~ The terms "cylinder volume" and "corrected cylinder opr re a p

wo volume" are units for measuring the degree of exp'nsion of a tion, tobacco. The term "oven-volatiles content" or "oven volatiles" a,0 04 0) 0?r avera ia on 0 '0 04 is a unit for measuring moisture content (or percentage of t

p)L )O and moisture) in tobacco. As used throughout this application, in arl ie 'to SO? the values employed, in connection with these terms, are a 4* 0?

steam determined as follows:

with Cylinder Volume (CV), :on- Tobacco filler weighing 10.000 g is placed in a 3.358-cm

forth diameter cylinder and compressed by a 1875-g piston 3.335-cm in a to ro diameter for 5 minutes. The resulting volume of filler is

reported as cylinder volume. This test is carried out at

standard environmental conditions of 23.9 0 and 607 RH; con- CCV ventionally unless otherwise stated, the sample is pre-condition- 33.2 50.1 ed in this environment for 18 hours. 57.2

Volume (CCV) Correed .Glinder

The CV value may be adjusted to some specified oven- volatile content in order to facilitate comparisons.

CV CV F (OV OVs) where OVs is the specified OV

and F is a correction factor (volume per predetermined for

the particular type of tobacco filler being dealt with.

Oven-Volatiles Content (OV)

SThe sample of tobacco filler is weighed before and

after exposure for 3 hours in a circulating air oven controlled

at 1000 C. The weight loss as perc';tage of initial weight is

oven-volatiles content.

For bright tobacco employed in the present applica-

rion, t- the value of F in the calculation of CCV is 7.6 on

average for gaseous CO2 expanded tobacco.

Unless otherwise indicated, all percentages used here-

in are by weight.

4.*

4

-36-

BCha~auen' I~ ~LLY~1L;.. rr_- iIi

Claims (9)

1. THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A process for expanding tobacco to achieve at least about 50 per cent increase in cylinder volume, comprising the steps of: contacting tobacco with carbon dioxide gas at a pressure of at least 250 psig and at sufficient temperature that substantially all of the carbon dioxide is maintained in gaseous form, for a time sufficient to impregnate the tobacco with carbon dioxide gas, (ii) decreasing the pressure, and (iii) thereafter heating the impregnated tobacco under conditions effective to liberate the carbon dioxide therein so as to cause expansion of the tobacco.
2. 2. A process according to claim 1 wherein the gaseous carbon dioxide and tobacco system in step is cooled to a temperature close to the saturation temperature of carbon dioxide but not lower than -23°C.
3. 3. A process according to claim 2 wherein the impregnated tobacco is cooled, at substantially constant pressure, to bring the enthalpy of the carbon dioxide to below about 140 BTU/lb.

   -36a- HS I

   I ~k~eI I kit I n I I I -e L

   INVNTION *RE A .EFINING FOLLOWS; 7 1. A process for expanding tobacco to achieve at east about 50 per cent increase in cylinder volume, co rising the steps of: contacting tobacco with carbon dioxid gas at a pressure of at least 250 psig and at suff'ient temperature that substantially all of the carbon di ide is maintained in gaseous form, for a time sufficie to impregnate the tobacco with carbon dioxide gas, (ii) decreasing the pressure and (iii) thereafter healing t impregnated tobacco under conditions effective to 1' erate the carbon dioxide therein so as to cause expansion of the tobacco. 2. A process ac rding to claim 1 wherein the impregnated tobacco is a temperature close to the saturation cooledo 0 temperature of/arbon dioxide but not lower than -23 C. 3. A pr ess according to claim 1 or claim 2 wherein the impregna d tobacco is at substantially constant cooled, press to bring the enthalpy of the carbon dioxide to below
4. 4. A process according to any one of the preceding claims wherein the pressure on the impregnated tobacco is reduced to substantially atmospheric pressure.
5. A process according to any one of the preceding claims wherein the contacting of tobacco with carbon dioxide is carried out at a pressure of from 400 to 800 p.s.i.g.
6. 6. A process according to any one of the preceding claims wherein the impregnated tobacco contains at least 1 part of carbon dioxide per 100 parts of tobacco.
7. 7. A piocess according to any one of the preceding claims wherein the impregnated tobacco is heated to a temperature in the range of 1000 to 370 0 C.
8. 8. A process according to any one of the preceding claims wherein the tobacco is impregnated with carbon dioxide at a temperature such that substantially all the carbon dioxide remains in gaseous form when the pressure is reduced to substantially atmospheric pressure.
9. 9. A process according to any one of the preceding claims substantially as hereinbefore described with reference to the examples. i. -37- J i a

   S

   tobacco temperaturre was found to be 2.2*C. The itapregnated

   sample had a weight gain of 2.07. which is attributable to

   A tobacco product prepared by the process according to any one of the preceding claims comprising at least 1 part by weight of gaseous carbon dioxide per 100 parts~ by weight of tobacco,

   DATED: 7 September, 1982.

   PHILLIPS ORMONDE AND FITZPATRICK Patent Attorneys for: PHILIP MORRIS INC.q-jr

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