Resin composition, optical compensation film using same, and production method for same

3:

• The resin composition according to claim 1,
• wherein the fumaric acid ester polymer is a fumaric acid ester polymer selected from the group consisting of:
• a fumaric acid ester polymer containing from 30 to 100 mol % of a diethyl fumarate residue unit and from 70 to 0 mol % of a fumaric acid monoester residue unit represented by the following formula (3);
• a fumaric acid ester polymer containing from 30 to 95 mol % of a diisopropyl fumarate residue unit and from 70 to 5 mol % of a fumaric acid monoester residue unit represented by the following formula (3);
• and a fumaric acid ester polymer containing from 30 to 95 mol % of a di-tert-butyl fumarate residue unit and from 70 to 5 mol % of a fumaric acid monoester residue unit represented by the following formula (3):
• (wherein R6 represents an alkyl group having a carbon number of 1 to 12).

5:

• The resin composition according to claim 1,
• wherein the fumaric acid ester polymer is a fumaric acid ester polymer containing from 70 to 99.5 mol % of a fumaric acid diester residue unit represented by the following formula (2) and from 30 to 0.5 mol % of a residue unit selected from the group consisting of an acrylic acid ester residue unit represented by the following formula (4), a methacrylic acid ester residue unit represented by the following formula (5), an acrylic acid amide residue unit represented by the following formula (6) and a methacrylic acid amide residue unit represented by the following formula (7):
• (wherein R4 and R5 represents an alkyl group having a carbon number of 1 to 12):
• (wherein each of R7, R8, R9 and R10 independently represents an alkyl group having a carbon number of 1 to 12, an alkylene group or an ether group).

9:

• The optical compensation film according to claim 7,
• wherein an in-plane retardation (Re) represented by the following expression (1) is from 80 to 300 nm and an Nz coefficient represented by the following expression (2) is from 0.35 to 0.65:
• Re=(ny−nx)×d (1)
• Nz=(ny−nz)/(ny−nx) (2)
• (wherein nx represents a refractive index in a fast axis direction in a film plane;
• ny represents a refractive index in a slow axis direction in a film plane;
• nz represents a refractive index outside a film plane;
• and d represents a film thickness).

11:

• The optical compensation film according to claim 7,
• wherein the in-plane retardation (Re) represented by expression (1) is from 0 to 20 nm and an out-of-plane retardation (Rth) represented by the following expression (3) is from −150 to 20 nm:
• Rth=[(nx+ny)/2−nz]×d (3)
• (wherein nx represents a refractive index in a fast axis direction in a film plane;
• ny represents a refractive index in a slow axis direction in a film plane;
• nz represents a refractive index outside a film plane;
• and d represents a film thickness).

15:

• A method for producing an optical compensation film according to claim 9, comprising:
• dissolving, in a solvent, a resin composition containing from 30 to 99 wt % of a cellulose-based resin as a cellulose ether, represented by the following formula (1), and from 70 to 1 wt % of a fumaric acid ester polymer containing 30 mol % or more of a fumaric acid diester residue unit represented by the following formula (2);
• casting an obtained resin solution on a base material;
• and
• after drying, separating a resulting film from the base material:
• (wherein each of R1, R2 and R3 independently represents a substituent having a carbon number of 1 to 12):
• (wherein R4 and R5 represent an alkyl group having a carbon number of 1 to 12).