| 摘要 |
PROBLEM TO BE SOLVED: To obtain a polyester improve in hue, etc., excellent in polymerizability by polycondensing a dicarboxylic acid component being an aromatic dicarboxylic acid or an esterifiable derivative thereof with a diol component in the presence of a catalyst being a metal phosphate. SOLUTION: The aromatic dicarboxylic acid or the esterifiable derivative thereof is terephthalic acid or a 1-4C alkyl ester or halide thereof. The diol component mainly consists of an aliphatic glycol, for example, ethylene glycol. The metal phosphate used is one obtained by reaction with an acid of tri- or penta-valent phosphorus or an ester thereof. It is desirable that the source of the metallic element of the metal phosphate include Ti or Sb. The source used is exemplified by antimony trioxide or tetra-n-propyl titanate. The esterification reaction is conducted under agitation at a temp. of 240-280 deg.C and 0-3 kg/cm2 at gauge for 1-10 hr. |
