Capacity fibers

Lithium niobate modulators have been used for a number of years in high capacity fiber optic transmission systems. The combination of an external modulator and a CW laser produces a more noise-free signal than a diode laser modulated by current drive. In spite of this advantage, large-scale use of modulators was not realized until recently because of earlier stability problems (Ko-rotky and Veselka, 1996). 

The decision of whether to apply one- or two-step melt spinning processes is rather complex and involves different criteria, such as line fiber capacity, fiber type, building costs, and labor and energy costs. 

Adipic acid is a very large volume organic chemical. Worldwide production in 1986 reached 1.6 x 10 t (3.5 x 10 lb) (158) and in 1989 was estimated at more than 1.9 x 10 t (Table 7). It is one of the top fifty (159) chemicals produced in the United States in terms of volume, with 1989 production estimated at 745,000 t (160). Growth rate in demand in the United States for the period 1988—1993 is estimated at 2.5% per year based on 1987—1989 (160). Table 7 provides individual capacities for U.S. manufacturers. Western European capacity is essentially equivalent to that in the United States at 800,000 t/yr. Demand is highly cycHc (161), reflecting the automotive and housing markets especially. Prices usually foUow the variabiUty in cmde oil prices. Adipic acid for nylon takes about 60% of U.S. cyclohexane production the remainder goes to caprolactam for nylon-6, export, and miscellaneous uses (162). In 1989 about 88% of U.S. adipic acid production was used in nylon-6,6 (77% fiber and 11% resin), 3% in polyurethanes, 2.5% in plasticizers, 2.7% miscellaneous, and 4.5% exported (160). 

A worldwide Hst of spandex fiber and related elastomer producers is shown in Table 2. Most process developments have occurred in the United States, Germany, Japan, and Korea. A large proportion of worldwide capacity is controlled by Du Pont, either directly or through subsidiaries and joint ventures. These include three plants in North America, two in South America, two in Europe, and two in Asia. 

Gut Rubber and Extruded Latex. The manufacturing technology for cut and extmded mbber thread is much older and more widely known than that for spandex fibers. Because production faciUties can be installed with relatively modest capital investment, manufacture of mbber thread is fragmented and more widely distributed with a few major and many minor producers. On a worldwide basis, Fikattice of Italy is the largest mbber thread producer with modem extmded latex plants in Italy, Spain, Malaysia, and the United States. Second in production capacity is the Globe Manufacturing Co., Fall River, Massachusettes with production operations in the United States and the UK. These firms also produce spandex fibers. 

Woddwide, the production capacity for polyester fiber is approximately 11 million tons about 55% of the capacity is staple. Annual production capacity iu the United States is approximately 1.2 million tons of staple and 0.4 million tons of filament. Capacity utilization values of about 85% for staple and about 93% for filament show a good balance of domestic production vs capacity (105). However, polyester has become a woddwide market with over half of the production capacity located iu the Asia/Pacific region (106). The top ranked PET fiber-produciug countries are as follows Taiwan, 16% United States, 15% People s RepubHc of China, 11% Korea, 9% and Japan, 7% (107—109). Woddwide, the top produciug companies of PET fibers are shown iu Table 3 (107-109). 

The People s RepubHc of China introduced Kuraray technology and started production of PVA fiber by a wet spinning process in 1965. Its annual capacity reached 165,000 tons in 1986 (9). The Democratic People s RepubHc of Korea produce PVA and reportedly have an annual production capacity of 50,000 tons (9). 

The acquisition of the rights to the viscose process became one of the most profitable investments of aU time. Interest in the new fiber was intense, and growth of production capacity was exponential. By 1907, the Courtauld company was selling aU the artificial sHk it could produce and proceeded to expand into the U.S. market. In 1910 they formed the American Viscose Co. and in 1911 started the first U.S. viscose factory at Marcus Hook. By 1939, Courtaulds had six factories in the United States, seven in the United Kingdom, one in Erance, one in Canada, and joint ventures in Germany and Italy. 

Approximately 2.5 million t of viscose process regenerated ceUulose fibers were produced in 1990 (Table 1). Measured by production capacity in 1990, the leading producers of filament yams in 1990 were the Soviet Union state-owned factories (255,000 t capacity) and Akzo Fibres in Europe (100,000 t). The leading producers of staple fiber and tow were Courtaulds with 180,000 t capacity spUt between the UK and North America Formosa Chemicals and Fibres Co. with 150,000 t in Taiwan Tenzing with 125,000 t in Austria, and a 40% stake in South Pacific Viscose s 37,000 t Indonesian plant and Grasim Industries in India (125,000 t). BASF s U.S. capacity of 50,000 t was acquired by Tenzing in 1992. 

Physical Dilution. The flame retardant can also act as a thermal sink, increasing the heat capacity of the polymer or reducing the fuel content to a level below the lower limit of flammabiHty. Inert fillers such as glass fibers and microspheres and minerals such as talc act by this mechanism. 

The most important appHcation of fiber-optic laser-based communication is in long-distance telecommunications (92,93). Fiber-optic systems offer very high capacity, low cost-per-channel, light weight, small size, and immunity to crosstalk and electrical interference. 

A composite dmm is constmcted of a plastic, semirigid inner liner (usually polyethylene) and either a steel or fiber outer container or overpack. The composite dmm may be a useful compromise between a plastic dmm and a conventional steel dmm. It is strong enough to be handled like a steel dmm, yet provides an enclosure for chemicals that cannot be shipped safely in steel or fiber dmms. Capacities of composite dmms are 19—208 L (5—55 gal). Such dmms are used in chemical, pharmaceutical, and food industries. 

Production, Storage, and Shipment. As noted above, AUco Chemical, Amoco Chemical, Mitsubishi Gas Chemical, and Hbls all produce either the acid or the anhydride using different production techniques. The relatively small production volumes of pyromellitic acid and dianhydride results in both storage and shipment in polyethylene-lined fiber dmms of 22—136-kg capacity. 

Because of the capacity to tailor select polymer properties by varying the ratio of two or more components, copolymers have found significant commercial appHcation in several product areas. In fiber-spinning, ie, with copolymers such as nylon-6 in nylon-6,6 or the reverse, where the second component is present in low (<10%) concentration, as well as in other comonomers with nylon-6,6 or nylon-6, the copolymers are often used to control the effect of sphemUtes by decreasing their number and probably their size and the rate of crystallization (190). At higher ratios, the semicrystalline polyamides become optically clear, amorphous polymers which find appHcations in packaging and barrier resins markets (191). 

Liquid sodium alumiaate is available ia steel drums having an approximate capacity of 210 L and bulk shipments are available ia either tank tmcks or railroad tank cars. The density of Hquid sodium alumiaate is usually from 1450 to 1510 kg/m. SoHd products are available ia moisture-proof paper bags or fiber drums containing approximately 23 and 150 kg, respectively. 

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