| 摘要 |
PURPOSE:To obtain a high polarization property and high wet heat resistance by constituting the polarizing film of a polymer mixture composed of different polyvinyl alcoholic (PVA) polymers and using a high-syndiotacticity PVA. CONSTITUTION:This polarizing film consists of the polymer mixture composed of the PVA having >=55% syndiotacticity and the PVA having 48 to 54% syndiotacticity. The PVA having >=55% syndiotacticity is obtd. by hydrolysis of polymers of vinyl ester of highly bulky side chains or vinyl ester of high polarity, such as vinyl pivalate, vinyl trifluoroacetate or decomposition of t-butyl vinyl ether or trimethyl silyl vinyl ether. The PVA produced by saponifying the polyvinyl acetate obtd. by polymn. of vinyl acetate and the denatured PVA formed by copolymerizing <=15mol% unsatd. carboxylic acid and unsatd. sulfonic acid, etc., as the PVA having 48 to 54% syndiotacticity. |
