| 摘要 |
PURPOSE:To obtain a board for magnetic disc or optical disc, which has favorable heat resistance and fabricability and excellent water vapor resistance, optical characteristics and solvent resistance, by a method wherein a specified resin composition, which is liquid under normal temperature, is integrally cured within a mold. CONSTITUTION:A board for magnetic disc or optical disc is manufactured by casting thermosetting resin, which is liquid under normal temperature, in a mold, at least one of disc-shaped molding surfaces is a mirror-finished surface or a surface having guide groove or information pit pattern. The thermosetting resin is a resin composition prepared by dissolving unsaturated epoxyester resin, which is obtained by reacting epoxy resin having at least two epoxy groups in a molecule and unsaturated carboxylic acid with each other in the presence of phosphine compound, in a copolymerizable monomer. The proper ratio of usages of the epoxy resin and the unsaturated carboxylic acid is 0.6-1.2 equivalents of carboxylic acid to one equivalent of epoxy group. Thus, a board, may be obtained the molding strain of which is extremely small, the optical strain of which is small, the releasability of which is excellent, the workability at demolding of which is favorable and which as excellent heat resistance and solvent resistance. |
