PRODUCTION OF SUBSTRATE FOR OPTICAL INFORMATION RECORDING MEDIUM

摘要

PURPOSE: To obtain a substrate with little warpage and little optical distortion by using such a copolymer polycarbonate as a polycarbonate resin that contains a component of carbonate bond structural unit (A) having at least one aromatic group dangled and a component of structural unit (B) having the group expressed by formula as the carbonate bond structural units. CONSTITUTION: The polycarbonate resin used is such a polycarbonate resin that has 10000-20000 average mol.wt. and contains a carbonate bond unit (component (A)) by 0-100wt.% of the total carbonate bond structure and a carbonate bond structural unit (component (B)) by 0-100wt.% in the units which constitute the carbonate bonds. The component (A) has at least one aromatic group dangled, while the component (B) has a group expressed by formula. The resin is molten and supplied to fill a mold and then pressed in an injection press- molding process to transfer a fine pattern, and then cooled in the mold for a specified time. The obtained substrate has little optical distortion such as double refraction so that it is suitable for an optical information recording medium for short wavelength.