| 摘要 |
PURPOSE:To suppress the deterioration of a recording film or reflective film by decreasing the amt. of the org. phosphorus compd. to be added to a polycarbonate resin to a certain numerical value or below and providing a dielectric layer between an optical disk substrate consisting of the polycarbonate resin and the recording film or reflective film. CONSTITUTION:The optical disk is constituted of the optical disk substrate consisting of the bis(hydroxyphenyl) alkane polycarbonate resin contg. the org. phosphorus compd. at <=0.002wt% in terms of a phosphorus atom and having 13,000-22,000 average mol.wt., the dielectric layer and the recording film or the reflective film. The org. phosphorus compd. is added to the resin as an antioxidant in order to suppress the heat deterioration (thermal decomposition) during molding and is preferably phosphite or trimethyl phosphate expressed by the formula. The optical disk which has good double fraction without giving ill effects to the film, is less decreased in the CN ratio and has excellent quality is thus obtd. |
