| 摘要 |
PURPOSE: A methacrylic copolymer satisfies excellent thermal resistance, low thermal expansion property, and transparency, and to have excellent thermal resistance and optical transparency, and to improve the thermal expansion property of a retardation film, thereby lowering the thermal deformation. CONSTITUTION: A methacrylic copolymer manufactured from a composition comprising 100 parts by weight of a monomer mixture, and 0.01-0.1 parts by weight of a cross linker having aromatic rings. A monomer mixture comprises 70-94 weight% of a maleimide monomer, 5-15 weight% of a maleimide based monomer, and 5-15 weight% of a methacrylic monomer. The glass transition temperature of the methacryl based copolymer is 250°C or higher. A methacrylic monomer is selected from a group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, metoxyethyl methacrylate, ethoxyethyl methacrylate, butoxymethyl methacrylate, hydroxyethyl methacrylate, and a C1-4 alkyl group. |
