POLYESTER, COMPOSITION THEREOF AND FILM THEREOF

摘要

Disclosed is a polyester film which has excellent dimensional stability against temperature and moisture. Specifically disclosed is a polyester containing a dicarboxylic acid component and a diol component, wherein (i) the dicarboxylic acid component contains not less than 5% by mole but less than 50% by mole of a repeating unit represented by the formula (A) below and more than 50% by mole but not more than 95% by mole of a repeating unit represented by the formula (B) below, and (ii) the diol component contains 90-100% by mole of a repeating unit represented by the formula (C) below. In the formula (A), R^A represents an alkylene group having 2-10 carbon atoms. In the formula (B), R^B represents a phenylene group or a naphthalenediyl group. In the formula (C), R^C represents an alkylene group having 2-10 carbon atoms.