To provide a cellulose ester-based optical film which is a melt-castable cellulose ester film, has a small retardation value and is excellent in surface quality and physical properties.
A method for manufacturing the optical film comprises the steps of: melt-casting a composition comprising the cellulose ester, which simultaneously satisfies the substitution degrees shown by expression (1): 2.50X+Y3.00, expression (2): 1.20X1.75 and expression (3): 1.00Y1.50 (wherein X is a substitution degree of an acetyl group; Y is a substitution degree of a propionyl group), and an ultraviolet-absorbing polymer to form a web; and stretching the obtained web to at least one direction by 1.2-5.0 times so that the obtained optical film satisfies 0Ro10 nm and -20Rth20 nm (wherein Ro is the in-plane retardation; and Rth is the retardation in the thickness direction) simultaneously.
SUZUKI TAKASHI
JP2007041280A | 2007-02-15 | |||
JP2006264312A | 2006-10-05 |
WO2007066519A1 | 2007-06-14 | |||
WO2007108347A1 | 2007-09-27 |
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