| 摘要 |
1,138,794. Cables. ALGEMENE KUNSTZIJDE UNIE N.V. 1 Dec., 1967 [1 Dec., 1966], No. 54878/67. Heading H1A. The extruded polyethylene terephthalate coating on an electrical conductor has a relative viscosity of at least 1À70 and a crystallinity of at least 15%. The coating is applied using molten polyethylene terephthalate having a relative viscosity of at least 1À80 containing 0À1 to 5% by weight of a crystallization promoter, cooling the coated conductor preferably not below the crystallization tempeature, and exposing the coating to a temperature of at least 100‹ C. until the desired crystallinity is achieved. The promoter may be inter alia a ketone, amine, or halogenated hydrocarbon, e.g. benzophenone, diphenylamine or tetraohloroethane, or tetralin or benzyl alcohol. The rate of crystallization may be increased by the addition of 0À001 to 0À5% of an undissolved solid substance having a particle size less than 3 microns, e.g. metal oxides such as magnesium oxide, finely divided metals such as copper or antimony, alkaline earth metal salts such as calcium carbonate and alkali metal salts of organic acids. As shown, conductor 2, which may already have an insulating coating of e.g. P.V.C., polythene, polyvinylidene fluoride, polysulphone, polyphenylene oxide, rubber or glass, is passed from supply reel 4 to heater 1 and extruder 8, and the coated conductor, air cooled in zone A, is passed through heating chamber 56, supplied with e.g. superheated steam at about 170‹ C. after crystallization. The coated conductor is cooled in chamber 16. |
