Polyester film for fabrication

摘要

A biaxially oriented polyester film comprising a copolyester which contains a lubricant having an average particle diameter of no greater than 2.5 mu m and has a melting point of from 210 DEG to 245 DEG C., the film having a plane orientation coefficient of from 0.10 to 0.16, a thermal shrinkage at 150 DEG C. of no higher than 10%, and a density of lower than 1.385 g/cm3, and optionally a refractive index in a direction of thickness of from 1.495 to 1.530 as well as a film plane refractive index of from 1.61 to 1.66 in all directions.