| 摘要 |
PURPOSE:To prepare a disk plate having excellent transparency, moisture warpage resistance, heat deformation resistance and formability, by using a copolymer resin composed of specific amounts of methyl methacrylate, alkyl acrylate, maleic anhydride and an aromatic vinyl monomer, as a substrate. CONSTITUTION:A copolymer resin is prepared by the polymerization of (a) 41-97.5mol%, preferably 41-70mol% of methyl methacrylate, (b) 0-5mol% of a 1-4C alkyl acrylate (preferably methyl, ethyl or butyl acrylate), (c) 1-26mol%, preferably 5-12mol% of maleic anhydride, and (d) 1.5-60mol%, preferably 18- 30mol% of an aromatic vinyl monomer (preferably styrene or p-methylstyrene), preferably in the presence of a radical initiator and chain transfer agent. The obtained copolymer resin is used as a substrate of a disk plate. Preferably, the amount of the residual monomer in the copolymer resin is <=1.0wt%, and especially, that of the residual maleic anhydride is <=0.1wt%. |
