PURPOSE: To prepare the subject oriented film consisting of a specific styrene- based resin composition, having a specific crystallinity, uneven thickness and dispersion of birefringence, excellent in plate property, hardly occuring deforma tion such as warpage when heating, stretch of line or waving, and useful for photographic film, etc.
CONSTITUTION: This oriented film is composed of a styrene-based resin composition containing 70-100wt.% of a styrene-based polymer having high syndiotactic structure (e.g. a polymer consisting of 80-100mol% styrene recurring unit and 0-20mol% p-methylstyrene recurring unit) and has ≥35% crystallinity, ≤8% thickness variation and ≤20% dispersion of birefringence in 100cm2 area. Furthermore, preferably, the oriented film has ≥5% dispersion of crystallinity, 70-250μm film thickness and ≥5% sum of thermal shrinkage factor in vertical and horizontal directions at 200°C for 5min.
UCHIDA TAKAAKI
KOGURE MASAMI
