CELLULOSE ACYLATE FILM, OPTICAL RETARDATION FILM, POLARIZING PLATE AND IMAGE DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a novel cellulose acylate film having a large absolute value of an in-plane retardation (Re) and a small absolute value of a thickness-direction retardation (Rth).

SOLUTION: The cellulose acylate film comprises a composition containing: at least one kind of cellulose acylate having acyl group (substituent A) containing an aromatic group and an aliphatic acyl group (substituent B), in which the degree of substitution (DSA) of the substituent A and the total degree of substitution (DS) of the substituent A and the substituent B satisfy respectively following expression (I) and expression (II); and at least one kind of a polymer having a number average molecular weight of ≥1,000. At least one kind of the polymer mainly contains acrylic esters or vinyl esters. Expression (I) is 0.5≤DSA≤1.0 and expression (II) is 2.0≤DS≤2.9.

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