Preparation of a polycarbonate by melt-polycondensation of a dihydric phenol and a carbonic diester

Abstract

A process for preparing a substantially chloride-ion-free, high-molecular-weight, colorless and transparent polycarbonate by melt-polycondensing a dihydric phenol with a carbonic diester, which comprises using a carbonic diester which is substantially free from (A) phenyl salicylate, o-phenoxybenzoic acid and phenyl o-phenoxybenzoate, (B) tin ion, (C) methyl phenyl carbonate or (D) phenyl salicylate and o-phenoxybenzoic acid. A process for preparing a thermally stable polycarbonate by melt-polycondensing a dihydric phenol with a carbonic diester, which comprises using a borate or, a compound selected from the group consisting of electron-donative amines and salts thereof as a catalyst, and optionally an acidic substance.

Dependencies are inferred from the claim text.