MANUFACTURE OF OPTICAL DISK SUBSTRATE

摘要

PURPOSE:To provide a manufacturing method of an optical disk substrate using a 4-methyl-1-pentene polymer or a 4-methyl-1-pentene copolymer superior in a transfer property. CONSTITUTION:The optical disk substrate is manufactured by a method that pellets of the 4-methyl-1-pentene polymer or the 4-methyl-1-pentene copolymer whose (a) melt flow rate (MFR) measured, based on ASTM D1238, at 5kg load and 260 deg.C temp. is 240-1200g/10min. and whose (b) m.p. by DSC is 234-240 deg.C, are molded by injection at a temp. of 320-370 deg.C at least at one part of the cylinder and at <=55 deg.C of metallic mold temp.