GB1377479A - Production of polyesters - Google Patents

Abstract

1377479 Polyesters IMPERIAL CHEMICAL INDUSTRIES Ltd 9 Dec 1971 [23 Dec 1970] 61168/70 Heading C3R A polyester or copolyester precursor or mixture of precursors is polycondensed in the presence of a compound in proportion equivalent to 15-150 parts per million of germanium dioxide, a trivalent antimony compound in proportion equivalent to 100 to 307 parts per million of antimony trioxide, and phosphoric acid or a phosphate ester in proportion equivalent to 50-6000 parts per million, the parts per million being based on the weight of terephthalic acid equivalent to the dicarboxylic acid or acids on which the polyester or copolyester is based. The germanium compound, which is soluble in the precursor or precursor mixture, may be amorphous germanium dioxide, germanium tetrachloride, or salt of a germanium acid or a reaction product of ethylene glycol with germanium dioxide or finely divided germanium metal. The antimony compound, which is soluble in the precursor or precursor mixture, may be antimony trioxide, antimony triglycoloxide, antimony triacetate or antimony trichloride. The phosphate ester may be triphenyl phosphate, triethyl phosphate, diphenyl propyl phosphate, dibutyl phenyl phosphate, tri-(2- hydroxyethyl) phosphate, dibutyl hydrogen phosphate or butyl dihydrogen phosphate. The germanium and/or antimony compound may be present during the preparation of the precursor. The polyester may be one prepared by the reaction of terephthalic acid or 1 : 2-bis-(4- carboxyphenoxy) ethane optionally in admixture with a minor proportion of adipic, isophthalic or 5-subphoisophthalic acid, with ethylene glycol or 1 : 4-tetramethylene glycol.