COPOLYESTERIMIDES DERIVED FROM N,N'-BIS-(HYDROXYALKYL)-PYROMELLITIC DIIMIDE AND FILMS MADE THEREFROM

摘要

A process for preparing a thermoplastic copolyester which comprises repeating units derived from an aliphatic glycol, an aromatic dicarboxylic acid, and the monomer of formula (I):; wherein n=2, 3 or 4, and wherein comonomer (I) constitutes a proportion of the glycol fraction of the copolyester, wherein the process comprises the steps of: (i) reacting said aliphatic glycol with said aromatic dicarboxylic acid to form a bis(hydroxyalkyl)-ester of said aromatic dicarboxylic acid; and (ii) reacting said bis(hydroxyalkyl)-ester of said aromatic dicarboxylic acid with the monomer (I) under conditions of elevated temperature and pressure in the presence of a catalyst, wherein the monomer (I) is present in a range of from 5% to about 20 mol % of the glycol fraction of the copolyester, wherein the aromatic dicarboxylic acid is selected from naphthalene dicarboxylic acid and terephthalic acid, and wherein the aliphatic glycol is ethylene glycol.