Patent ID: 7611760
Filing Date: 2009-11-03
Classification: C08B,C08J,C09K,G02B

Abstract:
1. A cellulose acylate film having an elasticity modulus of 4,800 MPa to 10,000 MPa in at least one direction of a machine direction MD in producing of the cellulose acylate film and a transverse direction TD perpendicular to the machine direction, the cellulose acylate film having an in-plane retardation Re(λ) satisfying Expression: 20 nm ≦Re(590)≦200 nm and a thickness-direction retardation Rth(λ) satisfying Expression: 70 nm≦Rth(590)≦350 nm, and the cellulose acylate film having a thickness of 40 μm to 150 μm; wherein the cellulose acylate film comprises mixed fatty acid ester of cellulose, wherein a hydroxyl group of the cellulose is substituted by an acetyl group, another hydroxyl group of the cellulose is substituted by an acyl group having 3 or more carbon atoms, and the cellulose acylate film satisfies Expressions (I) and (II): wherein A represents a substitution degree of the acetyl group, and B represents a substitution degree of the acyl group having 3 or more carbon atoms; and wherein the mixed fatty acid ester of cellulose is a cellulose acylate comprising a glucose unit, wherein a hydroxyl group of the glucose unit is substituted by the acetyl group or the acyl group having 3 or more carbon atoms, and the cellulose acylate film satisfies Expressions (III) and (IV): wherein DS2 represents a substitution degree of the acyl group for a 2-position hydroxyl group of the glucose unit, DS3 a substitution degree of the acyl group for a 3- position hydroxyl group of the glucose unit, and DS6 a substitution degree of the acyl group for a 6-position hydroxyl group of the glucose unit.