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t66hZZ l OSZ 50 % FILTER DILUTION FIG, 7 17.5 CC GENERATED MS SMOKE, I,E. ONLY HALF OF TO8ACCO IS BURNT . SMOULDERING: SAME AMOUNT OF TOBACCC IS BURNT AS IN NON- DILUTED CIGARETTE .0 %o

21 In the S0 percent diluted cigarette, nothing is changed in the free-burning phase between two consecutive puffs. As shown in Fig. 7, 50 mg of tobacco is consumed by smouldering. During the puff, however, the actual puff volume is not 35 cc as in the non-diluted cigarette, but only 17.5 cc. As a consequence, only 25 mg of tobacco are burnt in a puff. During a puff period - comprising one puff followed by the interval between two puffs - only 75 mg of tobacco will burn away in the 50 percent diluted cigarette, as compared with 100 mg in the non-diluted cigarette. Coming back now to our cigarette development- people, we are sorry to report that they unexpectedly failed in their attempt to achieve a 50 percent tar and CO reduction by a 50 percent filter dilution. Why? The answer is simple. They forgot to care about the puff count. The explanation is shown in Fig. 8. Since the cigarette contains 1000 mg of tobacco to be burnt, but only 75 mg arc burnt per puff period, the puff count increased from 10 in the non-diluted cigarette to 13.3 in the diluted ci~arette.

23 a They actually achieved a 50 percent tar and CO reduction PER SINGLE PUFF, bringing the per-puff deliveries down from 2 mg tar and CO to 1 mg tar and CO. But for the total cigarette the delivery is 13.3 mg tar and 13.3 mg CO. The reduction was not 50 percent as expected, but only 33 percent for both criteria. The TASTE STRENGTH, however, suffered a reduction of-50 percent, as taste is being perceived on a per-puff basis. 8tock 5 Abou.t taste .6thength and numbehs - Taste atn.ength ia peneeived pen pu55. - DeCiveky numbeics ane nepon.ted pen eiganette. rhete5one, bon, a gEven .tan numben pen eiga:ce.t.te: - Taste a.tnength ts .fneneased ti5 the pu6b count ~s &educed; on - I S we ineneaa ethe pu5 6 count, we too6e .tas.te stnength. That's the end of the story. Both attempts to reduce tar and CO by half had failed. They had to fail, because the cigarette-development people lacked the very capability without which filter dilution does not lead to really satisfactory low-delivery products.

25 This tool is expanded tobacco. Expanded tobacco is presently available to Philip Morris and one other major cigarette company only. Expanded tobacco (ET) is a commodity that burns like normal cigarette filler, with one notable exception: A given weight of ET fills twice the volume of the same amount of normal tobacco filler. This is illustrated in Fig. 9 Suppose now that we can build a cigarette which is made up in slices of equal length, i.e. of equal volume, filled alternately with ET and normal filler. Our model cigarette will have a total of 20 slices of 0.18 cc volume each. The odd-numbered slices 1 to 19 shall contain 25' mgtT each and be destined to burn during puffing,-i.e. to produce mainstream smoke. The even-numbered slices 2 to 20 shall contain S0 mg normal cut filler each and be destined to smoulder between the puffs. If our cigarette were fitted with a 50-percent diluted filter, we could actually observe to happen what we expected: Each time the smoking machine draws a puff, filter dilution will reduce the actual puff volume from 35 to 17.5 cc, but since the puff will act on a segment of ET filler, a full slice volume of 0.18 cc will be burnt. Between two puffs, twice the weight of tobacco filler will be consumed, but since this filler is not expanded, the slice volume is also 0.18 cc. The total ciaarette will burn down to the butt in 10 puffs and deliver not more than 10 mg tar and 10 mg CO.

27 The problem is that such a cigarette cannot be made. But let us postulate that we do not need to separate ET and normal tobacco filler in order to achieve the desired result. The goal of reducing by half both tar and CO would then be reached by combining 50 % filter dilution with a cigarette filler blended from equal volumes of ET and normal cut tobacco. Such a cigarette is shown in Fig. 10, from which it is easy to understand that the 1: 1 volume ratio corresponds to a 1/3 : 2/3 weight ratio between ET and normal cut filler. ' The total tobacco filler to be burnt adds up to 750 mg. Since one puff period consumes 25 mg (during the puff) plus 50 mg (between the puffs) = 75 mg of tobacco filler, the cigarette will burn down in 7 = 10 puffs. This is exactly what was intended. The proof is made, therefore, that the combination of filter dilution and a blend of ET and normal cut tobacco leads to the desired goal. It is even possible to derive a general rule, which is explained in Block 6. Stocfz 6 Ru.Ce o 5 -thumb In onden to heduce TAR and CO by X o wi.thou.t changing the PUFF COUNT - difu.te the 5it.ten by X % and - neptaee X$ 06 the 5-i.Qten votume by ET N ~ O ~

29 In order to make things clear, Fig. 11 shows how the goal has been achieved: A is the 20 mg tar cigarette from which we started. This cigarette delivers 10 puffs containing each 2 mg tar and 2 mg C0. Cigarette B is different from A only in that its filter is S0 percent diluted. Consequently, tar and CO are reduced from 2 to 1 mg per puff. Conclusion: Filter dilution controls the smoke delivery per puff. Second conclusion: With filter dilution we loose control of the puff count. In cigarette C we use ET as a filler component. This allows us to reduce the puff count from 13.3 (cigarette B) to the original 10 ' (cigarette A), all by maintaining the per-puff advantage gained by filter dilution. Conclusion: ET in the filler blend controls the puff count. Fitten ditut.fon and expanded tobaeco These two .Lndispensab.2e toot6 6on B.Coch 7 design.i.ng tow-de.fiveny e-i.ga&et#es ane bes.t ehanacten.Lzed as 5oQ.2ows: FILTER DILUTION contnots smoke numbens PER PUFF. EXPANDED TOBACCO in the 5ti.E-Cen btend con.tnots the PUFF COUNT.

31 Epilogue l Filter dilution and expanded tobacco are only two among many capabilities used for cigarette designing. Their contribution to cigarette development is invaluable, however. It can be said without exaggeration that without these two tools it would not have been possible to design the low- and ultra-low-tar cigarettes upon which the cigarette industry has to rely in order to safeguard the future of its business. To-day, only RJR and Philip Morris have their own technical process for expanding tobacco.' The other companies are compelled to develop the same or equivalent capabilities. The lead time for RJR and Philip Morris is not more than about two or three years. The Philip Morris brands of the future will have to be established on the markets within this very short period. If the people who develop, produce and market the Philip Morris brands are successful in their enterprise, the outlook will be quite bright for the Company. MAII/CI-fS/July 17, 1980 J