OPTICAL FILM, ROLLED OPTICAL FILM, POLARIZING PLATE, LIQUID CRYSTAL DISPLAY DEVICE, AND METHOD FOR MANUFACTURING OPTICAL FILM

摘要

PROBLEM TO BE SOLVED: To provide an optical film having a low shrinking force and a high elastic modulus.SOLUTION: The optical film comprises at least a compound having a repeating unit and a cellulose ester, and has an in-plane retardation (Re) of 10 nm or less at a wavelength of 590 nm and an elastic modulus of over 3.5 GPa. The compound having a repeating unit is a condensate of a polybasic acid and a polyhydric alcohol and satisfies the following conditions (1) to (6). They are: (1) the compound includes at least a polybasic acid having 5 or less carbon atoms as the polybasic acid; (2) the polybasic acid has an average number of carbons of 3 or more and less than 6; (4) the polyhydric alcohol has an average number of carbons of 2 or more and 3 or less; (4) all of repeating units constituted by combination of one polybasic acid and one polyhydric alcohol have 4 or more and 9 or less carbon atoms; (5) the compound has a number average molecular weight of 800 or more and 5000 or less; and (6) the compound has a hydroxyl value of less than 40 mgKOH/g.