MANUFACTURING PROCESS FOR POLYESTER FILM EXHIBITING LOW THERMAL SHRINKAGE

摘要

A process in which a wound roll of biaxially oriented polyester film having a glass transition temperature (Tg (°C)) is annealed at a temperature T a (°C) above Tg where Tg T a ‰¤ Tg + 100 (°C) for a time t after thermal equilibrium where 1 hour ‰¤ t ‰¤ 72 hours and cooled, for the purpose of improving the shrinkage of said polyester film.