Patent ID: 9512295
Filing Date: 2016-12-06
CPC Classification: C08J,C08K,C09K,G02B

Claim Text:
1. A polymer film comprising: a cellulose acylate, wherein a degree of substitution of acetyl groups substituted at the hydroxyl groups of the cellulose of the cellulose acylate is taken as SA, and a degree of substitution of acyl groups with 3 or more carbon atoms substituted at the hydroxyl groups of the cellulose of the cellulose acylate is taken as SB, wherein a high molecular weight plasticizer that has a number average molecular weight of 700 to 10,000 and has a repeating unit derived from a dicarboxylic acid and a diol, wherein the dicarboxylic acid for forming the high molecular weight plasticizer comprises at least one aliphatic dicarboxylic acid having 2 to 20 carbon atoms and at least one aromatic dicarboxylic acid having 8 to 20 carbon atoms, and the diol comprises at least one diol selected from the group consisting of an aliphatic diol having 2 to 12 carbon atoms, an alkyl ether diol having 4 to 20 carbon atoms and an aromatic ring-containing diol having 6 to 20 carbon atoms, wherein both ends of the high molecular weight plasticizer are at least one selected from the group consisting of an aliphatic group having 1 to 22 carbon atoms, an aromatic ring-containing group having 6 to 20 carbon atoms, an aliphatic carbonyl group having 1 to 22 carbon atoms, and an aromatic carbonyl group having 6 to 20 carbon atoms, wherein the high molecular weight plasticizer is contained in an amount of 2 to 30% by mass based on an amount of the polymer, and wherein the retardation values meet the following relational expressions: wherein the retardation values Re (H %) in the in-plane direction and Rth (H %) in the thickness direction at the time when the relative humidity is H (unit: %) are obtained by conditioning the film at 25° C. and a humidity of H % for 24 hours, and then measuring and calculating the retardation values at the time when the wavelength at a relative humidity of H % and 25° C., is 590 nm.