| 摘要 |
PURPOSE:A resin having moldability and specifications suitable for optically high-density information recording medium such as video disc, etc., comprising a copolymer containing a methyl methacrylate monomer unit, etc. CONSTITUTION:A resin comprising (A) a copolymer containing (i) methyl methacrylate monomer unit, (ii) an ester monomer unit of methacrylic acid and 3-6C monohydric saturated fatty alcohol, (iii) a monoalkenyl aromatic monomer (e.g., styrene, etc.), and (iv) an unsaturated fatty acid monomer unit and/or a 6-membered ring acid anhydride unit shown by the formula (R1 and R2 are H, or CH3), or (B) a copolymer mixture obtained by blending two or more of copolyers containing two or more units of the units i-iv, containing the units i- iv, having 2.5-10cps viscosity of the copolymer A or B in 10wt% methyl ethyl ketone solution at 25 deg.C, containing 40-70pts.wt. unit i, 4-16pts.wt. unit ii, 15- 35pts.wt. unit iii, and 1-9pts.wt. unit iv, having <=100nm birefringence. |
