BIAXIALLY STRETCHED POLYESTER FILM AND METHOD FOR PRODUCING SAME

摘要

The present invention relate to a biaxially stretched polybutylene terephthalate film comprising a polyester resin composition containing 60 % by mass or more of polybutylene terephthalate, wherein a peak temperature of tan ´ as determined by the dynamic viscoelasticity measurement at 10 Hz of measurement frequency is 60 °C or more and 100 °C or less in both the MD direction and the TD direction, and a peak value of tan ´ is 0.080 or more and 0.15 or less in both the MD direction and the TD direction. The biaxially stretched polybutylene terephthalate film of the present invention can be suitably used for converting films, films for food package such as a retort pouch package and a moisture food package, draw films and the like.