| 摘要 |
PURPOSE:To obtain an optical molded article superior in optical characteristics and difficult in hydrolyzability by using a resin compsn. of polycarbonate having a specified range of viscosity average mol.wt. contg. a specified amt. of trimethyl phosphate. CONSTITUTION:Polycarbonate used here has an viscosity average mol.wt. of 12,000-18,000 found by measuring its methylenechloride soln. at 20 deg.C, and when it is <12,000, the molded article is deficient in mechanical strength and not practicable, and when >18,000, it is deficient in fluidity even at 300-400 deg.C, resulting in forming optical strain. An amt. of trimethyl phosphate to be added is 0.001-0.05pt.wt. per 100pts.wt., and when it is <0,001pt.wt., enhancement of heat resistance cannot be expected, and when >0.05pt.wt. hydrolyzability is lowered. |
