Continuous launch production unit

Figure5.10 Continuous launch production unit R-01 at Lonza (by courtesy of D. Roberge/Lonza) [35].

Greater success was achieved by DuPont who copolymerized, the sodium salt of 5-sulfoisophthalic acid into PET to render the polymer dyeable with cationic (basic) dyes. Basic dyeable PET was successfully launched as Dacron 64 in the form of a low-pill staple product [64]. The presence of the sulfonate groups in the polymer chain also acts as an ionic dipolar cross-link and increases the melt viscosity of the polymer quite markedly. Thus, it is possible to melt-spin polymer with IV 0.56 under normal conditions, giving a low-pill fiber variant. The fiber also has a greater affinity for disperse dyes due to the disruption of the PET structure. Continuing this theme, there are deep dye variant PET fibers, often used in PET carpet yarns, which are copolymers of PET with chain-disrupting copolymer units like polyethylene adipate. They have less crystallinity and a lower Tg. therefore, they may be dyed at the boil without the use of pressure equipment or carrier at the cost of some loss of fiber physical properties. 

Since the launch of the first simple tablets, the unit dose form has become more complex almost every year thereafter. Some of them include dual layer tablets, tablets with inserts, and, recently, the multicompartment PVOH pouches. The need to remain competitive will continue to drive more complex forms of unit dose products for the foreseeable future. 

Up to the advent of World War II, practically all of the rubber consumed was of the natural variety, mostly derived from Hevea brasiliensis plantations in the Far East. With the entrance of Japan into the war, both the United States and western Europe were cut off from the main source. At this point one of the most massive organic chemistry research and development efforts in history was launched, which ultimately resulted in the development of synthetic elastomers such as Buna N, Neoprene, Thiokol, and styrene-butadiene. While these were not equivalent to the natural product in some respects, product improvement continued so that by 1970 worldwide synthetic rubber production was 3.8 million metric tons compared to 2.7 million of the natural product. Styrene-butadiene rubber sold for about the same price as natural rubber. Although national defense interest dictated a policy of independence from foreign raw materials, conventional bias-belted tires still required 15% natural rubber for optimum performance. 

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