AU427369B2 - Tobacco expanding process - Google Patents

Description

111 72 This invention relates to a process of treating

tobacco and has for an object the provision of a process

for increasing the filling capacity of a tobacco product. The present invention provides a process of in-

creasing the filling capacity of tobacco which comprises

contacting tobacco with vapors of an organic compound in the absence of the liquid or solid phase thereof, said

compound being chemically inert to.said tobacco and having an atmospheric pressure boiling point between about

and +80*C. and the. temperature of said tobacco during said

contacting being maintained above the boiling point of con- said compound at the pressure prevailing during said tacting, and thereafter, without cooling the resulting

tobacco to a temperature below the boiling point of said

compound at the prevailing pressure, subjecting the vapr-. con- impregnated tobacco to vapor releasing and expanding ditions whereby to expand the tobacco. Tobacco leaves when harvested contain a consid-

erable quantity of water and during the normal tobacco

curing process this water is removed by drying, resulting

in shrinkage of the leaf structure. In the usual process cigar or of preparing tobacco for storage and subsequent cigarette manufacture, the tobacco regains very little, if any, of the shrinkage resulting from the drying step so that a significant loss in the filling capacity of the

tobacco is the result. Thus, the cured tobacco has a

bulk density which is in excess of that required for mak-

ing satisfactory cigarettes or cigars. Also, during cut- cibar- ting of leaf or strips for making cut filler for to ettes, frequently the shreds are laminated together 4 7.369

39.11 1 72 orm hard, dense particles which occupy far less volume han the original shreds occupied. This is wasteful since hese hard compacted shreds are not necessary in the to- acco to produce an article which is satisfactory for mokdng. Several procedures have been suggested in the rior art for increasing the normal filling capacity of obacco. Certain of these procedures have involved puff- ng operations in which the tobacco is subjected to high ressure steam, followed by sudden release of pressure. uch processes have not usually been satisfactory since hey result in the production of excessive amounts of ines. Also, it has been suggested that the filling capa- ity of tobacco may be increased bulk density re-

uced) by exposing the tobacco to the vapors of an organic .iqild to condense the liquid in the tobacco followed by ir drying at ambient temperatures and pressures. How-

ver, such procedures have not been wholly satisfactory ecause they are not effective for increasing the filling apacity to any great extent. Another method that has

een proposed involves contacting the tobacco with a vola- ile organic liquid and then heating the liquid-impreg- ated tobacco to a temperature above the boiling point of he liquid whereby to vaporize the liquid directly in the obacco causing expansion. Embodiments of this last men- ioned procedure are described in United States Patent los. 3,524,451 and 3,524,452 issued August 18, 1970. Another object of this invention is the provi- ion of a tobacco treating process which involves the use )f vapors of an organic compound. 42736

39. 11172 A further object of this invention is the pro-

vision of a process for increasing the filling capacity

of tobacco under conditions such thtt the process can be

readily controlled to produce the desired product. An additional object of this invention is the

provision of a process for expanding tobacco using vapors

of an organic compound thereby eliminating the requirement

of handling large quantities of liquid in commercial oper- ations.

A still further object of this invention is the

provision.of a process for increasing the filling capacity of tobacco which may be readily adapted to a continuous

operation.. Further and additional objects will appear from

the following description and the appended claims.

In accordance with one embodiment of this inven-

tion, a process is provided in which a tobacco product is contacted with vapors of an organic compound or mixture'of

organic compounds in the absence of the liquid or solid

phases thereof, said contact being effected while main-

taining the temperature of the tobacco above the boling

point of the compound or mixture of compounds at the pre- vailing pressure. In this step the vapors are adsorbed

onto or absorbed directly into the tobacco particles.

Thereafter the tobacco is subjected to vapor releasing

and expanding conditions by suddenly decreasing the ambi-

ent pressure and/or by rapidly heating the impregnated

tobacco whereby to release and expand the vapor. The re-

sulting tobacco has a lower bulk density higher

filling capacity) than the untreated tobacco charged to 427.369

39.111 n the process and is suitable for use in the manufacture of smoking tobacco articles such as cigarettes, cigars, pipe tobacco and the like. The tobacco to be treated in accordance with the process of this invention is preferably a cured tobacco and may be in the form of shreds, strips, leaves, stems or sheets of reconstituted tobacco. However, the process is easier to control and the best results are obtained if tobacco shreds are used. This is for the reason that usu- ally shreds are relatively easy to handle in continuous procedures and the final product of the process need not be subjected to shredding as may be necessary for cigar- ette manufacture. Shredding of the final product results in compressing the product which tends to destroy the ul- timate objective of the process of this invention, namely, to expand the tobacco and eliminate compressed particles, as may have resulted from prior treatment Including shred- ding. Any type of tobacco may be used in the practice of this invention and it is particularly useful for the pro- cessing of burley, flue-cured and Oriental Turkish) tobaccos. Burley and flue-cured tobaccos used in the manu- facture of cigarettes ordinarily have a moisture content of about 10 to 20 percent by weight. In the practice of this invention, the moisture content of the tobacco when contacted with the organic vapor is preferably in excess of 8 percent by weight and suitably within the range of to 30 percent. The desired moisture content may be ar- rived at by drying the tobacco or by the addition of water, as may be appropriate. This latter may be effected 427.369

39.111 72 by any suitable procedure such as sprinkling, spraying,

wet steam treatment, or the like, as will be obvious to

one skilled in the art. The presence of the indicated

percentage of moisture is desired since the internal

structure of the tobacco is thereby rendered sufficiently

pliable or flexible to permit the expansion or puffing

when the vapors of the organic compound expand within the

tobacco upon pressure reduction or heating. If the mois- ture content is less than 8 or 10 percent, the process re- suits in the production of an excess of tobacco fines dur- ing the expansion step. A tobacco having greater than about 30 percent moisture has a tendency to be mushy or soggy and is difficult to handle in commercial operations. In accordance with this invention, the moist tobacco is contacted with the vapors of the organic com- pound in the absence of the liquid or solid phases under conditions which effect impregnation of the tobacco with the vapors. It is sometimes preferred, particularly if a low boiling organic compound is used, that the tobacco be subjected to a partial vacuum for a short period of time before vapor impregnation. This operation serves to re- move at least a portion of air or other gas that may be occluded within the tobacco particles or between the fibers thereby permitting more complete vapor impregnation

and absorption or adsorption of vapor on the tobacco par- ticles. The tobacco during vapor impregnation is main- tained at a temperature above the boiling point of the organic compound at the prevailing pressure. Preferably, the temperature of the body of tobacco is maintained at least 1°C. above said boiling point. The vapor impregna- S427.369

3. 111 72 tion step may be carried out at any convenient ambient pressure, atmospheric pressure being preferred in commercial operations. However, the impregnating pressure will, in part, depend upon the boiling point of the particular compound which, in the

vapor phase, is used for the impregnation. Also, it is preferred

that the temperature of the tobacco during the impregnating step 0 be less than about 100 C. so that no adverse effect is produced on the tobacco undergoing the treatment. When using vapors of

a compound having an atmospheric pressure boiling point above room temperature it will be necessary to carry out the impregna- tion at elevated temperatures and/or reduced pressures. During and impregnation the vapors enter into the minute spaces between within the tobacco particles and become absorbed and/or absorbed

on the particle surfaces. With vapors of the lower boilihg the organic compounds, the impregnation may be effected with tobacco maintained at ordinary room temperature. The impregna- at- ting vapors may contact the tobacco by subjecting it to an

mosphere containing in excess of 2 percent and preferably in excess of 5 percent by volume of the vapors over a period of the time such that a substantial amount of vapor permeates into tobacco and becomes absorbed or absorbed by the tobacco parti-

cles. Under certain conditions, as in the case of the highly

volatile Preons fluorinated hydrocarbons), the water-

moistened tobacco may be exposed to an atmosphere consisting essentially of the vapors of the fluid at atmospheric tempera- ture and pressure in order that the vapors may find their way is a directly into the tobacco during treatment. ("Preon"

Registered Trade Mark). The amount of M 427,369

39,111/72 non-aqueous vapor used for impregnation is critical to

the extent that sufficient vapor should be present as the

free vapor or in the adsorbed or absorbed states so that

when expanded a significant expansion of the tobacco will

occur. The amount to be used will depend upon the chem- ical compound whose vapors are utilized, the concentration

of the vapors in the impregnating atmosphere, the time of

contact for impregnation, the degree of tobacco expansion desired and the processing temperatures and pressures. In other words, it is important that the concentration of the organic compound.vapor in the impregnating atmosphere be high enough and the exposure to the impregnating atmos- phere be for a period sufficient to produce a treated to- bacco which will expand adequately. To achieve this re- sult the weight percentage of organic compound in the to-

bacco when subjected to the vapor expanding conditions is preferably in excess of.about 5 percent by weight. This relatively high percentage is readily achievable by vapor phase impregnation because the vapors are strongly ab- sorbed or adsorbed directly on the tobacco particles even

though the temperature of the tobacco is above the boiling point of the compound at the prevailing pressure.

The compound employed for impregnating the mois- tened tobacco is one which is chemically inert to the to-

bacco bieing treated and has a boiling point at atmospheric

pressure between about -50°C. and +80 0C. Compounds having boiling points above +80°C. do.not provide good tobacco

expansion and are difficult to remove completely from the tobacco without adve'sely affecting its flavor and aroma. Compounds having very low boiling points below 427.369

39.11 1 /7 obtainable pressures are so volatile under readily are not impreg- in commercial operations that the vapors degree at the time nated into the tobacco to the desired applied. Preferably, the vapor expanding conditions are of the compound is the atmospheric pressure boiling point between -400C. and 440°C. Illustrative inert organic com- and methyl ethyl ke- pounds are: ketones such as acetone such as methyl ethyl tone; aliphatic or cyclic ethers methyl butyl ether, diethyl ether, diisopropyl ether, tetrahydrofuran; ali- ether, dimethoxymethane, furan and ethanol and 2-propanol; phatic alcohols such as methanol, formate and methyl esters such as methyl formate, ethyl as butane, pentane, acetate; aliphatic. hydrocarbons such unsaturated hy-, isopentane, hexane and the corresponding such as cyclo- drocarbons; the cycloaliphatic hydrocarbons the halohydrocarbons butane, cyclohexane and cyclopentane; isopropyl chloride, sec- ethyl chloride, propyl chloride, methyl bromide, ethyl butyl chloride, t-butyl chloride, chloride, chloroform, bromide, tt-butyl bromide, methylene ethylidene carbon tetrachloride, ethylene dichloride, represented by trichloro- chloride; and the "Preon" liquids monochlorodi- monofluoromethane, dichlor6difluoromethane, and trichlorotrifluoro- fluoromethane, l,l-difluoroethane that are preferred are the ethane. The organic materials are relatively non-polar in non-oxygenated compounds which substantially immiscible in nature and are relatively or as a group have relative- water. These preferred compounds require only a low energy ly low specific heats and thus within the tobacco. Prefer- input to cause them to expand and the halogenated red materials are the hydrocarbons 427.369

39.111i hydrocarbons of the types indicated above. Mixtures of

vapors of several compounds may also be used if the boil-

ing points-_of the liquid mixtures are within the indicated temperature range. After the vapors have become thoroughly impreg- nated into the tobacco, the tobacco is then immediately and rapidly subjected to a vapor releasing and expanding condition whereby the vapors are released from the absorb- ed or adsorbed condition on the tobacco and the tobacco particles are expanded and puffed to the desired extent. This may be effected by a sudden increase in the tempera- ture or by immediately subjecting the body of impregnated

tobacco to a decreased pressure which may be accomplished by pressure release if the impregnation is carried out at superatmospheric pressure or by drawing a vacuum on the tobacco if the impregnation is effected-at atmospheric or moderately superatmospheric conditions. In the pressure release puffing procedure, the ambient pressure on the impregnated tobacco is reduced by at least 50 percent from one atmosphere to less than one-half atmosphere) and preferably in excess of. percent and the reduction is accomplished rapidly, usually within a period of less than one minute and preferably in less than ten seconds. Also, the temperature of the to- bacco at this point in time is still maintained above the boiling point of the organic compound at the decreased pressure so that vapor is released from the tobacco and expands. The tobacco is puffed and the vapors are expel- led from the tobacco. Generally, it is only necessary to maintain this reduced pressure for a few minutes, after 42 7.3 6 9

39.11 1/72 condition which time the tobacco retains its expanded

even though subject to changes in pressure. In the heat puffing procedure the vapor Im-

pregnated tobacco is rapidly heated, preferably by an less increment of at least 25°C. within a period of by than ten seconds, whereby the tobacco is puffed

release and expansion of the vapor due to temperature change without a corresponding increase in pressure. 0 C. The puffing temperature should not exceed about 230 adverse-, or the flavor.and aroma of the tobacco may be

ly affected. The puffing temperature is achieved by energy heating in any desired manner such as radiant

microwave). However, it is preferred to use serves a stream of hot gas, such as air or steam, which but also to not only to supply the puffing temperature from remove the released vapor of the organic material

the tobacco. Irrespective of the type of expansion pro- or- cess used it is desirable, at least with certain vapors ganic materials, to remove last traces of the expanded to- by passing a warm or hot gas through the bacco. The expanded tobacco is then reordered, if for the necessary, to-the moisture content desired

final product. This is usually carried out by wet moisture con- steaming, spraying, etc., and the final 10 to 20 percent tent is preferably within the range of

by weight. This tobacco product, having decreased the manufac- bulk density, is particularly useful for cigars and ture of smoking products such as cigarettes,

pipe tobacco. The bulk density having been decreased, -Il- 427.369

39.111/ 2 considerable savings In tobacco cost are obtained in the manufacture of these smoking products without sacrificing quality. In order to measure the filling value or capa- city of a cut filler tobacco product as described in the following examples, a measuring device was used which is essentially composed of a 100 milliliter graduated cylin- der having an internal diameter of about 25 millimeters and a piston having a diameter of about 24 millimeters and weighing about 802.5 grams slidably positioned in the cylinder. A three gram sample of tobacco was placed in the cylinder and the piston was positioned on it. The gravitational force exerted by the piston corresponded to a pressure of about 2.3 pounds per square inch. The fill- ing value of the sample was the volume to which the three gram sample of tobacco in the cylinder was compressed after the weight of the piston had acted on it for a per-" iod of three minutes. This pressure corresponds closely to the pressure normally applied by the wrapping paper to tobacco in cigarettes. The moisture content of the tobac- co affects the filling values determined by this method, therefore, comparative filling capacities of tobacco both before and after expansion were made with tobacco having essentially the same moisture contents. For a more complete understanding of this in- vention, reference will now be made to several specific examples of procedures for carrying it into effect. EXAMPLE 1 Shredded flue-cured tobacco having a moisture content of about 11 percent and a filling value of 14.9 427.369

39.111/17 milliliters/3 grams was treated with additional water to raise the moisture content to about 20 percent. The to-

bacco (20 grams) was then placed in a flask and heated to a temperature of 80 to 850C. by immersing the flask in a hot water bath. Thereafter, a stream of carbon tetrachloride vapor at about 770C. was passed through the tobacco for 2 hours at atmospheric pressure. The temperature of the tobacco during this time was maintained between 80 and above the boiling point of carbon tetra, chloride at the prevailing pressure). The vapor-impregnat- ed tobacco was then immediately transferred to a wire basket in a steaming chamber without lowering the temper- ature to any significant extent and exposed to steam at. atmospheric pressure and at about 1100C. for five minutes. After cooling and drying by exposure to air, the treated tobacco was reordered to the original moisture content of II percent and the filling value of the tobacco was found to be 20.2 milliliters/3 grams representing an increase of about 36 percent over the original control. EXAMPIE 2

Using essentially the same equipment and proce- dures specified in Example 1, shredded flue-cured tobacco grams) having a moisture content of about 12 percent by weight and having an initial temperature of about 300C. was expbsed to a stream of Freon-Il (trichloromonofluoro-

methane) vapor for two hours at atmospheric pressure. The

temperature of the tobacco during this time was maintain- ed at 30*C. by means of the water bath. The vapor-ipreg-

nated tobacco was then transferred to the steam chamber and treated with steam at 105-110*C. for one minute. The -13- 427.369

39,111/72 moisture content of the tobacco was then adjusted to about 12 percent by equilibration for 24 hours in a desiccator containing a solution consisting of 3 parts of glycerin and one part of water. The filling value as a result of the treatment increased from 12.5 milliliters/3 grams for the control of 15.5 milliliters/3 grams representing an increase of about 24 percent. EXAMPLE 3 Shredded flue-cured tobacco (20 grams) having a moisture content of about 11 percent by weight was placed in a stainless steel pressure reaction chamber equipped with a pressure gauge and an iron-constantan thermocouple. Freon-12 gas (dichlorodlfluoromethane) was introduced into the reaction chamber under a pressure of 60 p.s.i.g. This pressure was maintained for 5 minutes during which time the temperature of the tobacco remained between 10 and 200C. The apparatus was then closed off from the Freon-12 source and was heated until the temperature of the tobacco increased to 30°C. and the internal pressure of the appa- ratus was 140 p.s.i.g. After 1.5 minutes the pressure was quickly released by opening a valve and venting the apparatus to the atmosphere. The treated tobacco and. a control sample were then reordered to about 12 percent moisture and the filling value of the treated tobacco was found t6 be 20 mililiters/3 grams versus 16 millillters/3 grams for the control sample representing a filling capa- city increase of about 25 percent. EXAMPLE 4

Shredded flue-cured tobacco (20 grams) having a

moisture content of about 11 percent by weight was placed -14- 427.369

39.111 2 in a flask and exposed to reduced pressure corresponding to about 3 millimeters of mercury for a period of 2 min- utes. The evacuated flask containing the tobacco was then

immersed in an ice bath'and vapors consisting essentially

of Freon-12 were slowly introduced to return it to atmos-

pheric pressure. The tobacco was exposed to a slow stream

of Freon-12 vapor at atmospheric pressure for an addition-

al 15 minutes during which time the temperature of the to- bacco remained at about 5 0 C. as determined by a thermo-

couple placed in the tobacco mass. The flask containing

the impregnated tobacco was transferred to a water bath

at 50*C., and pressure within the flask was immediately

reduced to 3 millimeters of mercury. This reduced pres-

sure was maintained for 15 minutes after which time the tobacco was returned to atmospheric pressure and cooled.

Reordering of the treated tobacco and a control sample to

about 12 percent moisture content and measuring the fill-

ing values revealed an increase of 20 percent in the filling capacity of the treated sample over the control sample. EXAMPLE Shredded flue-cured tobacco having a moisture

content of about 11 percent and a filling value of about of Freon- 15.2 milliliters/3 grams was exposed to a stream 11 vapor for 2 hours at atmospheric pressure while main- 0 taining the tobacco at a temperature of 30 C. The vapor- a re- impregnated tobacco was then rapidly subjected to duced pressure corresponding to about 5 millimeters of

mercury and was maintained at that pressure for approxi-

mately 15 minutes. This reduced pressure was accco m3h-

39,111 !n ed in less than about one minute. After the vacuum was broken to the atmosphere the treated tobacco was then re- ordered to about the original moisture content, to give a final product having a filling value of 17.8 milliliters/3 grams representing an increased filling capacity of about 17 percent. EXAMPLE 6 The procedure of Example 2 was repeated except that the temperature of the tobacco during impregnation was maintained at 29 0 C. by means of the water bath and the impregnated tobacco was treated with steam at 140*C, for 1 minute to effect the expansion. The increase in the filling capacity of the tobacco as a result of this treat- ment was about 84 percent. EXAMPLE 7 The procedure of Example 3 was repeated except that before vapor treatment the moisture content of the tobacco was increased to about 20 percent and the Freon-12 gas was introduced into the reaction chamber under a pres- sure of 65 p.s.i.g. The pressure was maintained for minutes during which time the temperature of the tobacco remained between 16 and 18 0 C. The apparatus was then closed off from the Freon-12 source and was heated until 0 the temperature of the tobacco increased to 56 C. and the internal pressure of the apparatus was 202 p.s.i.g. After

minutes the pressure was quickly released by venting the apparatus to the atmosphere. After reordering to the original moisture content, the filling capacity of the tobacco was found to have been increased by 60 percent.

427.369

39,111 72 EXAMPLE 8

The process of Example 2 was repeated except

that pentane vapors were employed and the tobacco during 0 vapor impregnation was maintained at 38 C. Expansion was effected by passing steam at 11OC. through the tobacco

for 1.minute. The filling value of the original tobacco

was 15.5 milliliters/3 grams and of the expanded tobacco was 27.0 milliliters/3 grams representing an increase of 74 percent. EXAMPLE 9

A first sample (20 grams) of flue-cured tobacco

was exposed to a stream of Freon-11 vapor in a I-liter 3-

necked flask for 2 hours. The temperature of the tobacco 0 a was maintained at 29 C. by immersion of the flask in

water bath. The tobacco temperature was measured with an

iron-constantan thermocouple inserted in the center of the sample'. The source.of Freon-11 vapor was disconnected

from the flask and the tobacco heated rapidly by. a stream

of air from a heat gun which had been connected to one

neck of the flask. The temperature of the hot air was

120 0 C. The exposure time was 3 minutes. The puffed to-

bacco and an untreated batch of tobacco were reordered to the. same moisture content by equilibration over 3:1 (w/A) glycerin-water in a desiccator for 41 hours. The filling

value of the puffed sample after reordering was 20.2

milliliters/3 grams, and the filling value of the control

tobacco 16.0 milliliters/3 grams. The increase in filling

value was 26 percent. A second sample (20 grams).of the

same flue-cured tobacco was exposed to the hot air stream

without prior treatment with Freon-ll vapor. After re- -17- 427.369

39, 11 1 n ordering, the treated tobacco had a filling value of 19.0

milliliters/3 grams and the control tobacco 17.0 milli-

liters/3 grams. The increase in filling value was 12

percent. The foregoing examples are illustrative of pro-

cesses in which the tobacco is treated in batches. How-

ever, the process of this invention is particularly adapted to a continuous operation. One such continuous

operation is.as follows: EXAMPLE A stream of shredded flue-cured tobacco having

a moisture content of about 15 percent by weight is warmed

to a temperature of 40°C. and continuously passed into a

vapor impregnating chamber at a rate of about 1000 pounds

per hour. Vapors of Freon-11 gas at about the boiling point of the liquid 23.8*C.) are also passed into

the impregnating chamber at a rate in excess of 50 pounds

per hour. The chamber is maintained at essentially atmos- pheric pressure and at a temperature above the boiling

point of Freon-1l. The tobacco is advanced through the

chamber on a suitable conveyor during which time the va-

pors impregnate the tobacco and are adsorbed or absorbed thereby. After a residence time of 2 to 10 minutes the

stream of vapor-impregnated tobacco having essentially the

same weight ratio of tobacco and vapor charged to the

chamber is discharged into a stream of gas which is heated

to a temperature which is sufficient to raise the temper-

ature of the impregnated tobacco by an increment of at

least 25°0. within a period of less than about 10 seconds,

suitably 150 0 C. This rapid heating releases and expands -18- 427.369

39.111/72 Sthe adsorbed or absorbed vapors thereby resulting in ex-

pansion of the tobacco. The vapors are separated from the

expanded tobacco and a first portion may be heated and re- cycled as the hot expanding gas and a second portion may be sent to a Freon-11 recovery system as described in U.S. Patent No. 3,524,452. The tobacco is passed to a steam stripper to remove any residual Freon-11 and is reordered to the desired moisture content,

When applied to shredded tobacco, the product

of the process of this invention is essentially free bf

compressed laminated tobacco particles which are formed

incident to the initial shredding of the tobacco used as a charge stock. The product may be used to manufacture

cigarettes in the conventional manner or it may be mixed

with other tobaccos to provide a desired blend for use in

the manufacture of cigarettes or other smoking articles.

The process requires only a minimum amount of organic

compound. The vapor used for treating the tobacco in a

continuous, semi-continuous or batch process can be re-

covered and recycled to the system if desired.

By maintaining the organic compound in the vapor

state, the ratio of tobacco to impregnating compound can

be readily controlled in a continuous operation, extrac-

tion of soluble tobacco constituents by organic liquid is

avoided, and the migration of soluble constituents within

the tobacco is minimized. The cost incident to the use

and vaporization of excessive amounts of organic liquid

within the tobacco is likewise avoided.

-19- 427.369

Claims (1)

1. 39.111 72 The claims defining the invention are as follows:

   1. A process of increasing the filling capacity

   of tobacco which comprises contacting tobacco with vapors

   of an organic compound in the absence of the liquid or solid phase thereof, said compound being chemically inert to said tobacco and having an atmospheric pressure boiling point between abeut -500 and +80°C. and the temperature of said tobacco during said contacting being maintained above the boiling point of said compound at the pressure pre- vailing during said contacting, and thereafter, without cooling the resulting tobacco to a temperature below the boiling point of said compound at the prevailing pressure, subjecting the vapor-lmpregnated tobacco to vapor releas- ing and expanding conditions whereby to expand the tobac- co,

   2. The process of claim I wherein said atmos- pheric pressure boiling point is between -abemt -40° and

   3. The process of claim 1 or 2 in which the

   compound is a relative! non-polar organic material sub-

   stantially immiscible with water. 4. The process of claim 1, 2 or 3 in which the compound is selected from the group consisting of hydro- carbons and halogenated hydrocarbons. The process of any of the preceding claim in which the compound is selected from trichloromono-

   fluoromethane, dichlorodlfluoromethane, pentane or iso- pentane.

   6. The process of any e the preceding claim

   wherein the moisture content of the tobacco contacted with

   the vapors is between abeeout 10 and 30 percent by weight.

   427.369

   39,111 72 The process of any preceding claim wherein the step of

   lubjecting the tobacco to vapor expanding conditions includes ;he step of rapidly reducing the ambient pressure on the apor-impregnated tobacco by at least

   The process of claim 7 in which the reduction in ambient

   )ressure is at least fifty percent and is effected over a >eriod of less than one minute.

   The process of any one of claims 1 to 6 wherein the step

   f subjecting the tobacco to vapor expanding conditions Lncludes the step of rapidly increasing the temperature of the

   mpregnated tobacco to a temperature not exceeding 23000. The process of claim 9 in which the temperature increase

   Ls at least 25°C. and is effected in less than ten seconds. 11. The process of any preceding claim in which the amount of

   rapor in the tobacco when subjected to the vapor releasing and expanding conditions is at least 5 percent by weight.

   12. The process of any preceding claim wherein the temperature Df the tobacco during said contacting is at least 1 C. above boiling point of said compound at the pressure prevailing luring said contacting. 13. The process of any preceding claim in which said tobacco is shredded tobacco.

   14. The process of any preceding claim in which the vapors are present in a gaseous atmosphere in a concentration in excess of two percent by volume.

   A process of increasing the filling capacity of tobacco according to claim 1, substantially as herein described with reference to any one of the foregoing examples.

   21 427.369

   3 ,1.11 17.2 1972 DATED this FIFTEEN']TH day of FEBRUARY,

   REYNOLDS LEASING CORPORATION

   the Applicant patent Attorneys for SPRUSON FERGUSON

   42 7.369

   .39.111172