METHOD FOR MANUFACTURING BIAXIALLY ORIENTED POLYESTER FILM, AND BIAXIALLY ORIENTED POLYESTER FILM

摘要

PROBLEM TO BE SOLVED: To efficiently obtain a thin film having a high strength in a longitudinal direction and a lateral direction without trouble such as a breakage or the like. SOLUTION: A method for manufacturing a biaxially oriented polyester film comprises the steps of simultaneously biaxially orienting a substantially unoriented polyester film in the longitudinal direction and lateral direction of the film, and then sequentially biaxially orienting the film in the longitudinal direction and lateral direction of the film.