POLYETHYLENE TEREPHTHALATE RESIN FILM AND PROCESS FOR PRODUCING THE SAME

摘要

A polyethylene terephthalate resin film in which the difference in refractive index between a direction having an angle of 45° with the winding direction for the film and a direction having an angle of 90° with that direction, ?nab, is 0.015 to 0.060 and which satisfies the following requirements (1) to (5): (1) the ratio of the strength at break (TS) to the elongation at break (TE), TS/TE, in each of four directions is 0.6-2.6 (MPa/%); (2) the difference in width-direction thermal shrinkage (HS150) is 0.1% or less; (3) the HS150 is 0.7-2.0%; (4) the coefficient of thickness fluctuation is 6% or less; and (5) the film thickness is 70-400 µm.