| 摘要 |
1420367 Thermoplastic copolyesters E I DU PONT DE NEMOURS & CO 29 May 1973 [30 May 1972] 25466/73 Heading C3R A copolyester is derived from (a) a poly- (alkylene oxide)glycol of molecular weight 150-250 and a carbon to oxygen ratio of from 1À5 : 1 to 2À4 : 1, (b) a dicarboxylic acid of molecular weight not greater than 300, and (c) a diol, other than (a) of molecular weight not greater than 250, the copolyester containing 30-65% by weight of 1,4-butylene terephthalate units and 0-20% by weight of other units derived from (b) and (c) which are present in an amount of at least 6% by weight when less than 45% by weight of the copolyester consists of 1,4-butylene terephthalate units. The copolyesters may contain stabilizers, e.g. syn-dibeta-napthyl-p-phenylenediamine, and fillers, e.g. carbon black, silica gel, alumina, clay or chopped fibreglass. The examples describe copolyesters prepared from (a) poly(ethylene oxide)glycol, (b) dimethyl terephthalate, optionally with dimethyl isophthalate, and (c) 1,4- butanediol. |
