POLYVINYLALCOHOL BASED POLYMER FILM

摘要

PURPOSE:To provide a PVA based polymer film which shows only a low degree of curling at the time of dipping it in water or leaving it to stand in air. CONSTITUTION:The polyvinylalcohol based polymer film features that the average crystallinity (Xc) by the X ray transmission method is in the range of 50 to 75wt.% and the absolute value of the difference of the crysallinity index (DELTAA) between one surface and the other surface of the film is below 0.05, and also the absolute value of the difference of the crystal size (DELTAD) between one surface and the other surface of the film by the X ray reflection method is below 1.5nm.