Method for preparing acrylic copolymer resin for optical film and method for fabricating optical film using the same

A method for preparing an acrylic copolymer resin for an optical film, the method comprising:

• suspension-polymerizing an acrylic monomer containing a benzene ring, an alkyl(meth)acrylate monomer, and a (meth)acrylic acid monomer to prepare an acrylic copolymer;
• and
• thermally treating the acrylic copolymer at a temperature ranging from 240° C. to 300° C.,
• wherein the suspension-polymerizing comprises:
• a first polymerization operation of performing suspension polymerization at an initial reaction temperature ranging from 60° C. to 90° C. for two to three hours;
• and
• a second polymerization operation of increasing the temperature by 5° C. to 20° C., based on the temperature of the first polymerization operation, and additionally performing polymerization for one to two hours,
• wherein the acrylic copolymer resin for an optical film obtained by the preparation method includes glutaric anhydride, and
• wherein the acrylic copolymer resin for an optical film obtained through the preparation method includes 3 to 15 weight parts of an acrylic unit containing a benzene ring, 65 to 92 weight parts of an alkyl(meth)acrylate unit, 0 to 4 weight parts of a (meth)acrylic acid unit, and 5 to 16 weight parts of a glutaric anhydride unit, over 100 weight parts of the acrylic copolymer resin.