ORIENTED POLYESTER FILM

摘要

Disclosed is an oriented polyester film having a certain thickness which is excellent in dimensional stability at high temperatures and dimensional stability against temperature changes within the temperature range of use. Specifically disclosed is an oriented polyester film stretched in at least one direction and having a film thickness of 12-250 mum, whose base layer is mainly composed of polyethylene-2,6-naphthalene dicarboxylate. The oriented polyester film is characterized in that (1) the temperature expansion coefficient (alphat) at 30-100˚C is 0-15 ppm/˚C in both longitudinal and transverse directions; and (2) the thermal shrinkage rate at 100˚C in 10 minutes is not more than 0.5% in both longitudinal and transverse directions.