TEIJIN CHEMICALS LTD

Hagiwara Z Kishimoto K Yamazaki H Hagiwara Research Corp. Japan Electroruc Materials Corp. Teijin Chemicals Ltd. 

Polycarbonate Panlite L-1250 High mechanical strength Electrical parts Teijin Chemicals Ltd. 

Henkel Rearrangement of Benzoic Acid and Phthalic Anhydride. Henkel technology is based on the conversion of benzenecarboxyhc acids to their potassium salts. The salts are rearranged in the presence of carbon dioxide and a catalyst such as cadmium or zinc oxide to form dipotassium terephthalate, which is converted to terephthahc acid (59—61). Henkel technology is obsolete and is no longer practiced, but it was once commercialized by Teijin Hercules Chemical Co. and Kawasaki Kasei Chemicals Ltd. Both processes foUowed a route starting with oxidation of napthalene to phthahc anhydride. In the Teijin process, the phthaHc anhydride was converted sequentially to monopotassium and then dipotassium o-phthalate by aqueous recycle of monopotassium and dipotassium terephthalate (62). The dipotassium o-phthalate was recovered and isomerized in carbon dioxide at a pressure of 1000—5000 kPa ( 10 50 atm) and at 350—450°C. The product dipotassium terephthalate was dissolved in water and recycled as noted above. Production of monopotassium o-phthalate released terephthahc acid, which was filtered, dried, and stored (63,64). 

Source From Yasufuku, S., IEEE Elec. Insu. Mag., 11(6), 27, 1995 Teijin Ltd., High Tenacity Aramids Fibre Technora TIE-05/87.5 Asahi Chemical Industry America, Inc., Technical Brochure, Aramica Film, 1991 Akzo Nobel, Twron Product Information Yarns, Fibers and Pulp. 

Nonspandex elastomeric fibers are based on segmented polyesters the fibers produced can be melt-spim into threads (7). The generic name for these fibers has been designated as elastoesters by the Federal Trade Commission because even though they are similar to polyester fibers chemically, they are physically different enough to warrant a new name. Teijin Ltd. produces an elastomeric fiber of this type with the trade name Rexe (see also Polyesters, Fibers). 

Although PET and PBT are widely used, better thermal and mechanical properties are desired for some applications. Higher performance in semiaromatic polyesters was obtained from polyalkene naph-thalates. These semicrystalline polyesters are prepared by the condensation polymerization of naphtha-lene-2,6-dicarboxylic acid and flexible aliphatic diols. The naphthalene moiety imparts stiffness to the linear polymer backbone, leading to improved physical and mechanical, barrier, chemical resistance properties, and UV-ray screening performance. Poly(ethylene naphthalene-2,6-dicarboxylate), PEN, became commercially available from Teijin Ltd. in the early 1970s. PEN has a Tg and of 125 and 268°C, respectively [34]. Its structure appears in Fig. 1.18. 

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