PRODUCTION OF BIAXIALLY STRETCHED POLYAMIDE FILM

摘要

PROBLEM TO BE SOLVED: To produce a biaxially stretched polyamide film excellent in mechanical properties such as dimensional stability, transparency or pinhole resistance. SOLUTION: A non-stretched polyamide film is adjusted to 3.0-7.0wt.% in water absorption and subsequently preheated to 140-180 deg.C. This preheated film is simultaneously biaxially stretched at stretching temp. of 180-200 deg.C by a tenter method and subsequently heat-treated at 180-210 deg.C to obtain a biaxially stretched polyamide film wherein pinhole resistance strength is 1,200 gf or more and the oblique difference of a hot water shrinkage factor is 1.5% or less.