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Reconstituted Tobacco by Dr Nicolas BASKEVITCH Director of Research Speech delivered at the BEIJING INTERNATIONAL TOBACCO EXHIBITION Pekin, China September 22-28, 1987

Reconstituted Tobacco Reconstituted tobacco is an established component of not only American b/en- ded cigarettes, but a/so the entire range of cigarettes manufactured around the world. Today we%l/ook at this product, beginning with its history, and see how it has become a technically advanced material which is used as an important tool for cigarette design. History The concept of reconstitution is not a new one. In the patent literature we can find some bright inventors of the 1 9th century who were already motivated by the economical advantages of reclai- ming the by-products of the tobacco industry. It took a long time, however, before this concept became a commer- cial reality. The tobacco reconstitution process started with the mechanization of the cigar industry. Until the 1950's, all cigars were hand-made. The industry had a need for a leaf-like tobacco pro- duct in bobbin form to be used as a cigar binder. Reconstituted tobacco was first developed to meet this objective. It did not take long before the cigarette industry attempted to use reconstituted tobacco in cigarettes as a way of reclak ming otherwise unusable fines and shorts. The decade between 1950 and 1960 saw a big boom in the development of reconstituted tobacco processes. These developments started with Frankenburg from General Cigar Company in 1952, followed by American Machine and Foundry in 1956. During the same period, the U.S. cigarette manufacturers R.J. Reynolds, Liggett and Myers and American Tobacco were all working on their own processes. Peter J. Schweit- zer developed a reconstitution tobacco process based on papermaking techno- logy, which is used by Kimberly-Clark in the US and by its affiliate LTR Indus- tries in France in 3 of the largest tobacco reconstitution mills in the world. Kimberly-Clark and LTR Indus- tries not only have considerably deve- loped and improved this process, but have also transfered its technology to outside parties such as Philip Morris USA, the Soviet Union and Korea. In the meantime, other work was taking place in Europe, particularly in the field of casting and extrusion processes like those patented by Gerlach and Borgwaldt. Since that era, reconstituted tobacco has grown in importance. It was esti- mated that in 1964 about 70,000 metric tons of reconstituted tobacco sheet were used in cigarette manufac- turing. Today estimates show that this figure has increased and that over 200,000 metric tons are used world- wide, most of it produced by the paper- making process. As already stated, reconstituted tobacco was used for the recovery of factory by-products. However, in an effort to meet industry needs, scien- tists' research work using specially desi- gned reconstituted tobacco transformed the product into a tool for modifying smoke chemistry and cigarette physical properties. It was stated in the introduction that reconstituted tobacco is an established part of today's cigarette. As support of this statement, the following figure details the blend used in the most recent reference cigarette developed by the Tobacco Research Institute at the University of Kentucky. Blend for the 1 R4F Cigarette Flue-cured 32.54 % Buriey 20.04 % Oriental 11.09 % Maryland 1.08 % Reconstituted 27.17 % iKimberly Clark-process) Glycerine 2.80 % lsosweet 5.30 % Source : D.L Davre, A. Vaught, T.C. Tso and LP. Bush, CORESTA Congress-Vienna 119841 This reference cigarette, coded 1 R4F, . was designed to yield tar and nicotine deliveries near the U.S. sales weighted average. It can be seen that the blend contains about 27 % of reconstituted tobacco, made by the Kimberly-Clark process, used by LTR Industries. 2504087586 er4~~~b~#~~~fN Sources of Raw Materials for Reconstitution Basically, the raw materials for recons- titution include all tobacco materials which are, for one reason or another, unsuitable for direct use in the cigarette. This includes : scraps from the threshing operation dust and shorts from various pneuma- tic systems (dryers, coolers, silos, cutters) stem winnowings from the cigarette short stems, stem bits loose leaves which have poor burning characteristics birds'eyes from roll-your-own operations whole tobacco plants specially grown for reconstitution The processing of stems for their incor- poration into cigarettes blends poses various problems during cigarette manu- facturing. Since the physical structure of cut stems is different from that of strips, it is often difficult to obtain a homogeneous blend. There are two major processes availa- ble which allow stems to be incorpora- ted into a cigarette blend : - conditioning, rolling and cutting, known as Cut Rolled Stems (CRS), often combined with puffing, - reconstitution of stems. The major drawback of the CRS pro- cess comes from the need for a special stem processing line, as well as a second blending operation at the cut tobacco stage. This can result in an irre- gular tobacco blend containing rigid stem particles which prevent maximum production on modem high speed ciga- rette makers. Kimberly-Clark Reconstituted stems, in comparison, require only one blending operation. This method results in a very uniform tobacco blend. The selection of a reconstituted stem process eliminates the substantial investment and opera- ting costs that the sophisticated CRS process implies. As you can see, the amount of raw materials available for reconstitution is substantial. This explains the present activity in this segment of the tobacco industry. 13

Reconstitution Processes A number of reconstitution processes have been proposed in patents and several have been put into industrial practice. Generally speaking, all processes can be grouped into two general principles for assembling tobacco particles. Either you glue tobacco powder together with adhesives or you intertwine tobacco fibers on a papermaking machine. Gluing Tobacco Powder with Adhesives In the first type of process, small tobacco fragments are ground to a powder uniform in size, and then mixed with adhesives. The solvent for the adhesive is usually water, but a mixture of methylene chlo- ride and methanol has also been proposed. The adhesive is either a natural gum (like locust bean, tragacanth, arabic or guar) or a chemical derived from starch or cellulose (like hydroxyethyl amylose, hydroxymethyl and hydroxymethyl cel- lulose or sodium carboxymethyl cellu- lose). Deriving the adhesive from the tobacco itself by a treatment of the stems has also been suggested. The slurry of tobacco powder and adhe- sive is formed into a sheet, using any one of a number of techniques : - In the casting process, the slurry is cast on a moving stainless steel belt which passes through a drying tunnel to evaporate the water or solvent The adhesive forms a film in which the tobacco powder is imbedded. - In the extrusion process, the slurry is a thick paste which is pressed bet- ween steel rollers at high pressure. Once it has been formed into foil or flakes, it is then dried. Another method extrudes the tobacco paste through a multi-orifice die to directly form the tobacco shreds. - In the rnpregnation process, the slurry is used to impregnate a very porous paper. The resulting product is dried and calendered. - The dust impingement process or sandwich process does not use a slurry. Instead, the sheet is formed by spraying successively tobacco dust, adhesive and again dust on a moving stainless steel belt The resulting sheet is then dried. All these processes suffer from a com- mon problem : the products are very fragile and return to dust when manipulated. Natural Intertwining of Tobacco Fibers Papermaking Process The other principle for assembling tobacco particles utilizes the natural intertwining of the tobacco fibers achieved on a paper machine. This explains why this process is often cal- led the papermaking process. Two variations of the papermaking process have been developed : In the more simple version, a single- step papermaking process, the raw materials are dispersed in water. The mixture containing the fibers and the tobacco extracts is drained over a moving screen. The drained water, containing a large amount of solubles, is recycled to homogenize the feed raw materials. The sheet coming off the screen is dried and cut into strips. The second variation, a two-step papermaking process, is the most widely used around the world and has been developed by Kimberly-Clark. It consists of two main stages : Extrac- tion and Recombination. The raw materials are mixed with water and then pressed to separate the tobacco extract from the insolu- a comparatively low transformation cost attributed to the large output of the Kimberty-Clark reconstituting plants. a reduced tar delivery combined with a reduced biological activity of the tar for the Kimberly-Clark reconstituted product in comparison with the inco- ming raw material. This result was confirmed by the Institute of the Ger- man Association of Cigarette Manu- facturers in a study comparing diffe- rent sheet making processes. the third factor is the flexibility of the Kimberly-Clark process, which allows for a wide range of modifications in the physical structure and in the che- mical composition. The potential for altering the burning characteristics of the tobacco and for selectively modifying the smoke com- position is probably the major reason for the development of the Kimberly-Clark two-step papermaking process. Now that we have reviewed the diffe- rent tobacco reconstitution processes, let's come back to the advantages for CtGARETTE WEfGHT (mg) PRESSURE DROP ImmWG3 PUFF NUMBER TAR (mg/cig) Natural Tobacco Control 1 245 63 10.3 31.9 Dust Impingement process 1 653 88 13.6 34.4 Extrusion process between rollers 1 925 87 15.1 33.9 Reconstituted Slurry process Tobacco with water 1 591 81 12.1 31.4 2 step papermaking process (K-C/ LTR Industries) 1 245 75 7.9 15.6 Slurry process with organic solvent 1 228 61 7.1 26.6 Source : W. Dontenwdl et al.- Zenschnh fur Krebsforschung Vol. 78 p 236-264 119721 ble fiber. It must be stressed that no chemical additives are used in this operation. The fibers are then disper- sed in water and drained over a moving screen to form a base sheet. In the meantime, the tobacco extract is concentrated and later added to the base sheet. The resulting reconstitu- ted tobacco is dried and cut into strips. The widespread use of the two-step papermaking process developed by Kimberly-Clark and LTR Industries during the last 30 years is attributed to three factors : cigarette manufacturers to transform by products into reconstituted tobacco. These advantages can fall into three categones : - Economical considerations N - Practical considerations C~ - Potential for cigarette design ~ O 00 J ~ 00 J 'J1qIllI 1 14

Economical Considerations 7 -I The economical incentive to recover factory by-products for an expensive com- modity like tobacco looks obvious. However, we must go into more detail to see exactly how reconstitution can be advantageous to the cigarette manufacturer. The first subject for attention is fil- ling power. The fil- s~ ling power of tobacco particles decreases signifi- cantly as their size is reduced. This relationship is illus- trated in Graph I. As a consequence, their inclusion in a cigarette adds weight without fil- ling the volume. When we look at the relationship between the weight of different cigarettes made from tobaccos having various fil- ling powers, we can see in Graph 2 that an increase in the filling capacity of a poor filler comes up to a lar- ger tobacco savings than when the same increase in filling capacity is applied to a good filler. 5 -~ 3 -~ 2-~ Relationship Between Filling Power & Cut Tobacco Particle Size 1_~ 0 ~ r r 05 10 15 SIEVE MESH SIZE (mmi FILLING POWER Icm' gI 2504087588 05 CIGARETTE CUT TOBACCO WEIGHT igi 10 15 If we push this argument to the limit, we can say that the reconstitution of small tobacco particles with a poor filling value can be more interesting economically for the cigarette manufacturer than the expansion of good filling tobaccos. Obviously this is true only if the resulting reconstituted tobacco has a good filling power, and, if it does not desintegrate during cigarette processing. It is clear that some reconstitution processes perform better than others in these two areas. IIiI~IVN'~i'i f ~III!II~I iu I'lll!IIII~'v~l~ NDUSTRIES FILLING POWER Icm' gi Relationship Between Filling Power & Cigarette Tobacco Weight I i I Practical Considerations We come now to the practical conside- rations. Reconstituted tobacco arrives at the factory in strip form. It can be intro- duced in the blend after vacuum humi- dification, but some manufacturers pre- fer to blend it directly. Obviously, reconstituted tobacco does not have to be threshed. This elimina- tes the unavoidable losses which occur during this operation. The following sequence shows the ope- rations involved to introduce reconsti- tuted tobacco into a blend : Storage of cases prior to use Case is opened and ready to add Case is turned for unloading into the feeder Strips being loosened Reconstituted Tobacco is conveyed and blended with Oriental tobacco in a heated drum This preblend is then distributed over a stream of other tobacco types, which is conveyed to the blending silos Leaving the silos, the blend of recons- tituted and natural tobacco is very homogeneous. As far as casing and flavorings are con- cerned, two possibilities exist. Recons- tituted tobacco can pass through the casing drum. It has been recognized that Kimberly-Clark reconstituted tobacco can be a very good absorber for casings. Alternatively, casings can be applied during the reconstitution process. This has the advantage of giving a very homogeneous distribution. Aromatic additions are used to bring a typical character to the cigarette smoke, like Oriental or Burley notes and finally, to harmonize the reconstituted tobacco with the remainder of the blend. Influence of Kimberly-Clark Reconstituted Tobacco on Cigarette Design The last consideration which I would like to cover is the potential offered by Kimberly-Clark reconstituted tobacco for cigarette design. Numerous techniques, sometimes in competition between each other, are at the disposal of cigarette designers to reach their objectives. The art in ciga- rette design is to understand the utility and the limitation of each technique. The following examples demonstrate how reconstituted tobacco can be used as a tool for the cigarette designer. It should be noted that the examples which follow all use reconstituted tobacco made by the Kimberly-Clark two-step papermaking process and the results will vary if material coming from another type of process is used. 15

2504087589 Reducing Tar Delivery The tar yield in reconstituted tobacco is primarily dependent upon its physical struc- ture. Numerous studies, and particularly those of the Research Institute of the German cigarette manufacturers association have demonstrated that substantial reductions can be obtained by reconstituting tobacco with the Kimberly-Clark pro- cess used at LTR Industries. Influence of Reconstitution on Tar Yields When Kimberly-Clark reconstituted to- bacco is blended in a cigarette, even with introduction rates ranging from 10 to 30 percent, a substantial reduction of tar yield can be reached. A practical example, obtained on a non filtered cigarette is shown in the follo- wing table. Natural Reconstituted Reduction Tobacco Tobacco mglcig mgicig % Virginia 35.1 24.0 32 Burley 21.9 15.5 29 Dark blend 20.5 15.7 23 German blend 30.7 22.5 27 W Oontenwdl et al. Zeitscnnfl fur Krebsforschung 85 141 153 (19M Plain Cigarettes (Flue-Cured Blend) Blend with 20 % Control without reconstituted tobacco reconstituted tobacco LTR lndustries Cigarette Weight (mg) 935 941 Pressure Drop (mmWG) 50 52 Puff Number 8.5 7.6 Tar (mgicig) 25.0 21.2 Nicotine (mgicig) 1.5 1.3 Now let us look at the more complica- ted situation of nicotine versus tar. Increasing Nicotine In natural tobacco tar yields are generally proportional to nicotine yields in the sense that a"high nicotine" tobacco will generally yield a high amount of tar. The Kimberly-Clark paper process of reconstitution used by LTR Industries ena- bles to increase nicotine rates up to the desired level without modifiying tar yield. This result can be achieved either by inclusion of very high nicutine content tobac- cos such as "Nicotiana Rustica", tobaccos in the blend to be reconstituted or by the addition of nicotine salts. The following table demonstrates that the introduction of a Kimberly-Clark recons- tituted tobacco (KCRT) with a nicotine content of 2.7 % in a blend with a nico- tine content of 1.76 % permits an increase of the nicotine delivery, and at the same time a reduction in tar delivery. Increasing Bum Rate W hen tobacco is grown on a soil con- taining chloride salts, as this is often the case near the sea, it takes up chloride in its leaves. A high chloride tobacco has poor bur- ning characteristics ; as a consequence the puff number is high and so are the tar deliveries. Sometimes, the tobacco does not burn at all. By developing a highly porous structure during the reconstitution process, then further by adding a burn-enhancing additive, it is possible to transform a non burning tobacco in a reconstituted tobacco with very acceptable bum rate. Static Bum Rate Chloride mm/mn Original 6.5 % does not bum Tobacco K-C RT 5.2 % 4.25 LTRI K-C RT 5.0 % 5.26 LTRI + Bum additive Reducing the Biological Activity of Tar A large amount of work has been devo- ted to the evaluation of the biological activity of the tar delivered by cigarettes. For this evaluation, various research ins- titutes have adopted the same techni- que which is called "mouse skin pain- ting". It consists in depositing a given dose of smoke condensate on the skin of a mouse, every day, during a period of 6 to 18 months, and then by eva- luating the number and the type of resulting tumors. Professor Dontenwill, Head of the Research Institute of the German Asso- ciation of cigarette manufacturers published over a period of ten years bet- ween 1970 and 1980, the results of his "Experimental Studies on Tumorigenic Activity of cigarette smoke condensate on mouse skin". "lJJI,JMm Increasing the Nicotine to Tar Ratio Nicotine fortffied 0 20 100 (KCRT) in blend (%1 Blend Nicotine l%/ 1.76 1.95 2.70 Smoke Nicotine (mgicig) 1.12 1.23 1.36 Tar (mgicig) 13.2 10.8 6.8 In one of the first publications he com- pared different reconstitution processes and found that there was only one pro- cess which gave a significant reduction in the bioactivity of the tar : this was the Kimberly-Clark process used by LTR Industries. 16

iillpyllylpf Comparison of the tumorigenic activity of condensates obtained from natural and reconstituted tobaccos (Mouse skin painting test) Cigarette Smoke condensate (mgJcigf % Anirtlals with tumours Natural tobacco 33.3 23.6 Tobacco sheet EA 32.6 32.4 Tobacco sheet EB 35.2 36.0 Tobacco sheet ES 16.9 14.2 (LTR-Industries product) Tobacco sheet EW 35.7 24.9 Source : Excerpts from W DONTENWILL et AL Zenschrrtt Fur Krebstorschung 78 236264 119721 Following this publication, many ciga- rette manufacturers decided to start to use reconstituted tobacco manufactu- red by the Kimberly-Clark process used by LTR Industries, or to switch from the casting process that they were using to the Kimberly-Clark process. As a consequence, the production of reconstituted tobacco at LTR Industries increased by a large factor. In another publication, Professor pon- tenwill compared the tumorigenic acti- vity for different types of natural tobac- cos, and of the corresponding recons- tituted tobaccos. The following graph confirms that reconstitution by the paper process reduces the bioactivity of the tar by about 50 %, for all types of tobaccos. Carcnomes at 40 mg Dose Naturai Tobacco Carcunomes '. aose level 40 m9 Cl k f Ki b l ar m er y- Effect of Introduction o Reconstituted Tobacco made by LTR Industries in a on carcinogenic activity of condensate 30 20 100 0 so Natural Tobacco 0 so K-C Reconstituted Tobacco 100 Reconstituted Tobacco was originally developed for economical reasons. This is still the major reason for its use. China produced 1.300 billion cigarettes in 1986. We can estimate that over 100.000 tons of tobacco by-products have been generated during the manu- facture of these cigarettes. During the same time China production of natural tobacco has been over 2 million metric tons. We can estimate that at least 100.000 tons of b y-products have been generated at the various manipulation stages in the forms and from the forms to the cigarette plants. Reconstitution of Blend ~ ~ ~ 00 FleConslRUfetl Tobacco ~ ~ the by-products will have an obvious economical interest either by allowing to increase the amount of cigarettes manufactured from the same quantity of leaf tobacco, or by allowing to manu- facture the same quantity of cigarettes with a lower consumption of leaf tobacco. Thus giving a larger potential for leaf export. On top of the economical interest, Kimberly-Clark reconstituted tobacco is nowadays an important tool for ciga- rette design. The use of Kimberly-Clark reconstituted tobacco can significantly modify the smoke chemistry, burning O Effect of Reconstitution by Kimberly-Clark Process on Biological Activity of Condensate From Dontenwdt Z. Fur Kresoforch. 85 141-153 1976, When reconstituted tobacco is introdu- ced in a blend, the bioactivity of the cigarette is reduced, and this true even when the level of introduction in the blend is moderate. As a conclusion, we can state that the introduction in Chinese cigarettes of reconstituted tobacco made by the Kimberly-Clark process used at LTR Industries would result in an improve- ment of the biological effect of cigarette smoke. and physical properties of cigarettes. It can contribute to the manufacture of cigarettes with better health charac- teristics. Within the Kimberly-Clark Group, LTR Industries is keen on developing its busi- ness relationship with China. Toda y in Beijing were are at your entire disposal to discuss cigarette design, selection and testing of specific types of reconstituted tobacco, direct supply of reconstituted tobacco from LTR Industries and future technological coo- peration in China. 17