| 摘要 |
PURPOSE:To improve a long-term shelf life by using a transparent substrate formed by molding an epoxy resin contg. a hydrolyzable chlorine at <=300ppm. CONSTITUTION:This optical disk is constituted of the transparent substrate molded of the epoxy resin and a memory function film installed on the substrate in direct or indirect contact therewith. The epoxy resin is essentially required to contain the hydrolyzable chlorine at <=300ppm. The hydrolyzable chlorine is referred to as a saponifiable chlorine as well. The epoxy resin made from epichlorohydrin usually includes 3 kinds of the structures expressed by the formulas. A hardner is added to the epoxy resin to cure the same. The preferable hardener is exemplified by a phthalic anhydride, 3-chlorphthalic anhydride, 4-chlorphthalic anhydride, etc. |
