Biaxially oriented polyester film and method for producing biaxially oriented polyester film

摘要

A biaxially oriented polyester film comprising a polyester resin composition containing 60% to 100% by mass of polybutylene terephthalate resin (a) and having a laminated number of not more than 7 and satisfying the following requirements (1) to (4).(1) the intrinsic viscosity of the biaxially oriented polyester film is 0.7 DL / g or more.(2) the surface orientation. Delta. P of the biaxially oriented polyester film is 0.145 to 0.160.(3) the piercing strength of the biaxially oriented polyester film measured by the piercing test according to jis-z1707 is 0.40 n /. Mu. M or more.(4) the thickness of the biaxially oriented polyester film is 0.7% or less.