Courtaulds

Carbon and Graphite Fibers. Carbon and graphite fibers (qv) are valued for their unique combination of extremely high modulus and very low specific gravity. Acrylic precursors are made by standard spinning conditions, except that increased stretch orientation is required to produce precursors with higher tenacity and modulus. The first commercially feasible process was developed at the Royal Aircraft Fstablishment (RAF) in collaboration with the acrylic fiber producer, Courtaulds (88). In the RAF process the acrylic precursor is converted to carbon fiber in a two-step process. The use of PAN as a carbon fiber precursor has been reviewed (89,90). 

Electrically Conducting Fibers. FlectricaHy conducting fibers are useful in blends with fibers of other types to achieve antistatic properties in apparel fabrics and carpets. The process developed by Nippon Sanmo Dyeing Co., for example, is reportedly used by Asahi in Casbmilon 2.2 dtex (2 den) staple fibers. Courtaulds claims a flame-resistant electrically conductive fiber produced by reaction with guanadine and treatment with copper sulfide (97). 

Chemical Applications. Courtaulds has developed a series of acryHc-based fibers for controUed release of chemical reagents. The trade name of these fibers is Actipore. The reagents are entrapped within the fiber and slowly released at a rate dependent on the exact porosity of the fiber (102). 

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. 

Tire Ya.rns, A method to iacrease the strength of viscose yam from the 0.2 N /tex (2.2 gf/den) standard to levels needed ia tires was first patented by Courtaulds ia 1935 (18). By raising the ziac concentration ia the spia bath to 4% the thread could be stretched more by immersing it ia a hot dilute acid bath duting extension. Filament strengths iacreased to about 0.3 N/tex (3.3 gf/den), and the cross section became rounder, with a thicker skin than regular viscose. Pairs of these yams were capable of beiag twisted iato tire cords which outperformed traditional cotton cords. 

Cross-sectional modifications of a more extreme nature than skin-bursting, which nevertheless do not form crimp, have grown in importance since the early 1980s. These yield a permanent bulk increase which can be translated into bulky fabrics without the need for special care. The first commercial staple fiber of this type was Courtaulds hoUow Viloft, developed in the 1970s using a carbonate inflation technique (37). 

Both American Enka (87) and Courtaulds set up pilot-plant work in the eady 1980s with the objectives of developing fiber spinning and solvent... 

The Courtaulds Tencel Process. The increasing costs of reducing the environmental impact of the viscose process coupled with the increasing likelihood that the newer cellulose solvents would be capable of yielding a commercially viable fiber process led Courtaulds Research to embark on a systematic search for a new fiber process in the late 1970s. 

The Courtaulds semicommercial production system is iUustrated in Figure 8. Dissolving-grade woodpulp is mixed into a paste with NMMO and passes through a high temperature dissolving unit to yield a clear viscous solution. This is filtered and spun into dilute NMMO whereupon the ceUulose fibers precipitate. These are washed and dried, and finally baled as staple or tow products as required by the market. The spin bath and wash Uquors are passed to solvent recovery systems which concentrate the NMMO to the level required for reuse in dissolution. 

The Y-shaped rayon data are based on Courtaulds Galaxy fiber. 

Envirocell, Pco-pwfiling of Celklose-BasedProducts, a study prepared for Courtaulds and others, Aug. 1990. 

Lane and McCombes, Courtaulds Challenge the Cotton Eegend, ACS Symposium Series 58, ACS, Washington, D.C., 1977, Chap. 12. 

D. C. Coleman, Courtaulds An Economic and SocialHistoy, Vols. 2 and 3, Clarendon Press, New York, 1980. 

Process. Any standard precursor material can be used, but the preferred material is wet spun Courtaulds special acrylic fiber (SAF), oxidized by RK Carbon Fibers Co. to form 6K Panox B oxidized polyacrylonitrile (PAN) fiber (OPF). This OPF is treated ia a nitrogen atmosphere at 450—750°C, preferably 525—595°C, to give fibers having between 69—70% C, 19% N density less than 2.5 g/mL and a specific resistivity under 10 ° ohm-cm. If crimp is desired, the fibers are first knit iato a sock before heat treating and then de-knit. Controlled carbonization of precursor filaments results ia a linear Dow fiber (LDF), whereas controlled carbonization of knit precursor fibers results ia a curly carbonaceous fiber (EDF). At higher carbonizing temperatures of 1000—1400°C the fibers become electrically conductive (22). 

In Europe, 1. G. Earbenindustrie decided to develop nylon-6 that had been synthesized from S-caprolactam using an aminocaproic acid catalyst (1) and commercially introduced as Pedon L in 1940 (11,12). 1. G. Earbenindustrie had evaluated over 3000 polyamide constituents without finding an improvement over nylon-6 and nylon-6,6 (13). In Italy, Societa Rhodiaceta started making nylon-6,6 in 1939. In the United Kingdom, ICl and Courtaulds formed British Nylon Spinners in 1940 and started to manufacture nylon-6,6 in 1941. 

Courtaulds North America, Inc. 45 La Moyne, Ala. rayon manufacture... 

Data from the following technical data sheets PAN fibers Amoco Performance Products, Asahi Kasei, BASE Stmctural Materials, Courtaulds-Grafil, Hercules, Mitsubishi Rayon, Toho Beslon, Toray Pitch fibers Amoco Performance Products, Mitsubishi Kasei, Tonen Corp. 

In 1988, Courtaulds took over Hercules 50% interest in Nelsons Acetate. 

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