| abstract |
PROBLEM TO BE SOLVED: To mainly produce a cellulose ester capable of obtaining sufficient flatness as a polarizing plate protective film, capable of stably carrying out a stretching operation, and satisfying plasticizer retention. An optical film made of the composition is obtained by melt film formation. An optical film formed by melting a composition mainly comprising cellulose ester, wherein the cellulose ester satisfies the following formulas (1) and (2). Formula (1) 2.4 <= X + Y <= 2.9 Formula (2) 0.3 <= Y <= 1.5 (Wherein X represents the degree of substitution with acetic acid and Y represents the degree of substitution with aromatic carboxylic acid) [Selection figure] None |