| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical film that has a small photoelastic coefficient and a low haze, and is excellent in adhesion to a polarizer and interface adhesion between each layer when bonded by a conventional alkaline saponification method. <P>SOLUTION: An optical film includes an "A" layer containing an acrylic resin having a weight average molecular weight exceeding a million, and a "B" layer containing a first cellulose acylate and a second cellulose acylate each having a different acyl substitution degree. A content ratio of the first cellulose acylate to the second cellulose acylate is 90/10 to 60/40 (mass ratio). The acyl substitution degree of the second cellulose acylate satisfies an expression (1) and at least one of expressions (2A) and (2B), with the expression (1): 2.55≤X+Y≤3.0; the expression (2A): 0.2≤Y≤1.2; and the expression (2B): -0.075n+0.72≤DS(n)≤-0.33n+2.88, where "X" is an acetyl substitution of the second cellulose acylate; "Y" is a substitution degree of an acyl group with carbon number 3 to 7 in the second cellulose acylate; DS(n) is a substitution degree of an acyl group with carbon number "n" in the second cellulose acylate; and "n" is an integer between 3 to 7). <P>COPYRIGHT: (C)2013,JPO&INPIT |
