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~ESE~CI-I ~.i~D D~VELOP~E~-T ESTABLISiq~ENT B~ITISH-AME~ICAN TOBACCO COMPANY LIMITED Tolopho~8 CONFIDENTIAL RESEARCH INFORMATION R.T.S. 10].l. THE FIRMNES~ IMPROVEMENT OF CIGARETTES Several techniques are available for improving the firmness of cigarettes. Studies in R. & D.E. have con- centrated on the treatment of mix%ures of cut lamina and C.R.S., stemstand C.R.S. alone, all re'lating to Virginia tobacco. The following factors have been found to have a general influence on fillin~ power :- (1) Choice of leaf, (2) Cultural practices. (3.) Artificial aging. (~) Cuttin~ machine design, (5) Cuts per inch. (6) CON processes. (7) Solv.ent treatment ('~ither spraying or extraction). (8) Water treatment. ~ (9) Drying techniques which are adopted. (10) Casings and fiavourings, (ll) Moisture content at making, (12) The in~er-ac~ion between tobacco particles in the cigarette. The firmness, improvement which can be obtained in C.R.S. alone is generally reflected pro rail in the final cigarette. In other words, if the C.R.S. has a firmness improvemen$ of 8% and is present in the cigarette at a level of 25% then the cigarette firmness will be improved by2%.

-2- liodifications to the C.I{.5. process which give rise to a product of Creator filling" po~or include (13) increasing the moisture content o£ stems prior ~o rollin~ and (l~) Increasing the Gap width of ~h8 rollers. (15) Decreasing cuts pe~ inch. (16) Increasing moisture conton~ of (17) CON processes. (18) Increased bulkinc times. (19) Drying ~echniques ~'hich are adopted. Considering now the above techniques in more detail. (i) Choice of leaf It is well known that the choice of leaf can have a marked effect on the firmness of the final cigarette. Filling capacity varlos widely between grades and growths. (2) Cultural D~nctJ.cos As an example of these, it is known tha~ tobacco which hms been treated with m~leie hydrazide generally appears to "have a reduced filling capacity. (3) Ar~iflci~l Tobacco can be artificially and rapidly aged by ralsin the temperature 9t which i~ is '~Zored. I~ these circum- stances tobacco is found to darken and its filling power increases. C~ttlnq machine ~czi~n The choice of cutting machines can have an effect on the firmness of the final cigarette and the Legg ~|illicutter has advantages in this ~ospect over ~he Molins Mark 1 machine (I-2% filling power). (5) c~t~ per Changes in cuts per inch ~¢i!i change the firmness of the final ciGnrmtte, an increase of approximately i0 cuts per inch givinG rise to a decrease of i% in firmness,

-3- (6) CON processos The CON processes for improvin~ the fillin~ po~'er of CU~ tobacco have been avai!eble for about eight ),ears. In ~heso processes sto~m is in,coted into cut tobacco in a vertical or semi-vc~tical Gravity food pipe and the steam temperature. 0n exit from %he pipe, ~oba~co is discharged into a dryer. Tile p~ocoss can Give rise ~o filling power in%provomcn~s of 2-~ ~nd results in some darkenin~ of the ~obacco. The same process c~n be (7) Solvent treatment (either snrayin~ or extraction) The firmness of cigarettes can be affected either by extraction of the tobacco wi~h such solvents as methyl chloride o~ by sprnyi:~ ~he ~obacco with a solven~ such as e~hyl alcohol. i£ the moisture con~en~ of cut tobacco is increased by ~l,o addition of wa~or throuch ~ spray, ~'he firmness of ~he final ciGare~t~ is also found ~o increase of the type of subsequent drying operation. Wi~h a max- imum obtained moisture content of 22~, increases in firm- ness of between 2-~ can be achieved. The me,hods used in dryin~ tobacco can affec~ the filling power of the final pro.duct; this is 'most likely due to some pr6cess similar ~o ~he processes of wettin~ or CCNNING described above. In ~he c~se of ~u~ tobacco steam can be injected into a rotary d~yer or the air flow can be reduced to a low level and moved in a dlrec~ion counter ~o ~he tobacco flow. In both ~heso cases fillin~ of the produce can be increased by so,us 2-3','~. Similarly, filling power of ~he produc~ from the pneumatic dryer can be varied and controlled by the adjustment of the moisture con%en~ of ~he circulatinG air in the dryer. Dielectric dryinx, when applied to cigarettes and used ~o remove 2~ water, %'ill increase ~he fitness Replacin~ the normal ~roon leaf redryin~ process by freeze dryin~ has also been reported to be v~ry effective, since ~hls is a method of retainln~ the oriGi~l leaf s%ruc~ur~ and avoidinG shri~caGe.

~'.:'.o effect of casings ~nd flavou~ings has not been studied closely but thoz~o a~e indications that the p~ose~ce of casings reduces the filling po~er of the product at equilibrium moisture content and it would be expected that the effect of flavou~ing material could be to increase the product fir~n~oss, depending on the solvents present. (i!) ~-~oiature content at It has been found that hizher than n~rmal moistur~ content Virginia tobacco used in ~,~olins ~4ark 8 making machines gives a product of improved fir:nness~ 1% increase in moisSurs .giving a l~ increase in fi~-mnsss and an improvement in ends stability. It must be roalised, however, that this is cow, plod with the otho~~ effects, particularly irregularly filled ~nds for example, ~;hlch ~zay not be desirable. (12) T~lo inte~-action It is also known that c:~uain~ the tobacco particles in ~ho cigarette tO become C!uod together l~ill make the cigarette firmer. No commercial techniques for this, ho~,ovel-, are yet availablo. (13) Increa~in:~ the ,no[,~~u1~c content of ste~m~ prior to rolling and cuttin~ Large improvements in fil~in~ power .are obtained by increasin~ the moisture content of stems before and/or after rolling and cutting. The maximum moisture content which the material reaches during processing appea~s to determine its final filling power. Before cutting and rolling, each increase in ~Oisturo content of the stem 1% up to a maximum level of about 50% will give rise to an increase in firmness of at least 1%. Since in normal processing the maximum moisture content reached is about 3~%, possible increases in C.R.S. filling power of at least 18~ are obtainable. Ho~.:cver, increased moisture: cont~n~s at this point lend to handling problems, part- icularly in subsequent cutting operations. (l~) Increasing ~%o Ca~.~idth of the rollers An increase in sto:z mollem clearance will give small increases in C.R.S. fill!zc po~er, up to abo~t l~.

-5- ChanCes i~ tho ~-:id'ah of cu% from 200 ~o IdO cuts per inch will also give an improvemen~ of about i~. (16) Incvea~in,~ ~olst,lr~ co:~~on'~ of C,~S. The addition of moisture after cutting has similar effects to the ~ddition of moisture before rolling (i.e. of the order of 17& filling power improvement for each i% wa$er added).. Largo improvements in filling power can be obtai:~ed and these are usually accompanied by slight changes in the colour of the product, which are Just detectable by eye, and a marked increase in the pressure drop of the cigarette. It is also likely that there are s~z~ll losses of tobacco substance (loss than O.l~) in addition to increased offal production. This process is the one most widely used in production a~ present. It is one feature of the St, Pauli process and of related processes using ~4a%er treatment alone, In those processes the moisture content of C.R,S. after cutting is raised from about 32~ up to ~5-30~& by ~¢ater spraying in either a cylinder or conveyor system follo~ed by bu!|=ing for about 30 minutes and steaming in a second cylinder or Gravity pipe. The C.R.S. is tllen par dried either in a rotary cylinder or an air dryer, it should be noted that this process calls for a considerable increase in par dryer capacitg (17) c02~,,procosse~ Processes such as the CON process, in which tile tobacco is steamed before dr>,InC, ca~l also be used on C.R.S'. and will Give improvements in the region of 3-3½%. (18) Increased bulk!9c times As a general rule, after stem or C.R.S~ has been con- ditioned it has been found that allowing the stem/C.R.S, to bulk for a short time will give rise~ to small improvements in firmness.

-6- (19) D~vln~ ~echninuos ~.~hich ~ro ~do~ted The type of dryer used has b~on found to influence the fiilinj po~¢er of C.R.S., a direct ~as heated rotary roaster ~ivin~ a product lo~or in filling power than that obtained from either a contra-flow steam heated cylinder dryer or an air dryer. The difference can be as much as differel%co in "nose" produced by the different dryin~ methods has been found to disappear relatively quickly after the cigarettes have been packed. ~he question of the additivity of these many various effects is not clear. However, it has been sho~n ~ith mixtures of cut lamina and C.R.S. that when two Identical CONCYL processes follow one another the filling power of the product is slightly lower than that which would have been obtained had only one CONCYL process been used. On the other hand, if a wetting process applied to the ~hole cigarette tobacco is applied to CONCYL the final filling power improvement of the product is less than the sum of the two ~mprove~|onts expected from the processes operated separately but greater than that which would be obtained f~om either process operated on its own. ~.~%ere stem/C.R.S. treatment is concerned, if the above described process changes are used in combinatio~ then improvements in filling power between material produced from the worst and the optimum processing conditions could be as great as 30% which, at 25% of the final cigarette, means an improvemmnt in cigarette firmness of about In all cases actual filling power improvements are dependent on local circumstances; them are related to the amount of filling power improvement already inherent in the processes being used and to the type of tobacco being used. Figures quoted in this sheet are therefore n guide; actual figures need to be determined by experiment and statistical verification.

-7- ~uch of the infommntion con~ined in this document. could be ro~arded as beinc p&tentable. However, as a matter of general policy, in order to maintain secrecy, " although from tame to time patent applications have been made those have not been pursued to completion. ISSUED BY: DATE: Dr. F. llaslam. .; Dr. S,J. Green. 27th March, 1969.