Kuraray

In the late 1980s, new fully aromatic polyester fibers were iatroduced for use ia composites and stmctural materials (18,19). In general, these materials are thermotropic Hquid crystal polymers that are melt-processible to give fibers with tensile properties and temperature resistance considerably higher than conventional polyester textile fibers. Vectran (Hoechst-Celanese and Kuraray) is a thermotropic Hquid crystal aromatic copolyester fiber composed of -hydroxyben2oic acid [99-96-7] and 6-hydroxy-2-naphthoic acid. Other fully aromatic polyester fiber composites have been iatroduced under various tradenames (19). 

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). 

Boric acid/alkaU spinning has been commercialized in Kuraray Co. and Unitika Co. in Japan, and is reportedly under research and development also in the People s RepubHc of China as a process for producing high strength PVA fiber to be used for replacing asbestos (9). 

Based on the technology developed for using PVA fiber as a replacement for asbestos in cement products, Kuraray has been developing thick fibers for reinforcing concrete (42). Super-thick fibers with a thickness of 39 tex (350 den) (200 p.m in diameter) to 444 tex (4000 den) (660 p.m in diameter) are now available the 39 tex material is used for reinforcing various mortar-based cement products and the 444 tex material for reinforcing concrete in civil engineering works such as tuimels, roads, harbors, and bays. 

Product brochure, Kuraray Co. Ltd., Okayama City, Japan, 1988. 

Much of the work with regard to this process was done by the French Petroleum Institute (113) and by the Kuraray Co. (108). In the CIS, a sinulat process which begins with cmde C s was developed (114). A one-step process that begins with isobutylene and methanol has been disclosed (108,115). This process is beheved to have significant economic advantages over the original route. 

Significant improvement in the fiber stmctuie of leather is finally achieved by using microfibers as fine as 0.001—0.0001 tex (0.01—0.001 den). With this microfiber, a man-made grain leather Sofrina (Kuraray Co., Ltd.) with a thin surface layer (Fig. 7), and a man-made suede Suedemark (Kuraray Co., Ltd.) with a fine nap (Fig. 8) were first developed for clothing, and have expanded their uses. Ultrasuede (Toray Industries, Inc.) also uses microfibers with a rather thick fineness of 0.01 tex (0.1 den). Contemporary (1995) man-made leathers employ microfibers of not mote than 0.03 tex (0.3 den) to obtain excellent properties and appearance resembling leather. 

Fig. 10. Formation of fibers used in Kuraray man-made leather (a) porous fiber, and (b) a bundle of microfibers.

Japan Kuraray Clarino, Sofrina, Suedemark, Amara, Amaretta 18 33... 

Y. Sonobe, private communication, Clariao Division, Kuraray Co., Ltd., Osaka, Japan, Sept. 30, 1993. 

Functional Olefin Hydroformylation. There has been widespread academic (18,19) and industrial (20) interest in functional olefin hydroformylation as a route to polyfiinctional molecules, eg, diols. There are two commercially practiced oxo processes employing functionalized olefin feedstocks. Akyl alcohol hydroformylation is carried out by Arco under Hcense from Kuraray (20,21). 1,4-Butanediol [110-63 ] is produced by successive hydroformylation of aHyl alcohol [107-18-6] aqueous extraction of the intermediate 2-hydroxytetrahydrofuran, and subsequent hydrogenation. 

Kuraray has commercialized a process for producing 3-meth5l-l,5-pentanediol [4457-71-0] from 3-methyl-3-butenol (20). 

In other work, sulfone chemistry plays an integral part of the syntheses of both -carotene and vitamin A by workers at Kuraray. In this approach, the anion of C q P-cyclogeranyl sulfone (36) is condensed with the C q aldehyde (37). The resulting P-hydroxy sulfone (38) is treated with dihydropyran followed by a double elimination to yield vitamin A acetate. Alternatively, the P-hydroxy sulfone (38) can be converted to the 5-halo sulfone (39) and a similar double elimination scheme is employed (23,24) (Fig. 8). 

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