SUBSTRATE MATERIALS FOR TRANSPARENT INJECTION MOULDED PIECES

摘要

A polymeric material suitable for making a substrate for optical data storage disks is disclosed. The material, preferably aromatic polycarbonate is characterized in that the potential on 95 to 100% of the total surface of a disk molded therefrom is from -1.5 to +1.5 kV, and in that the potential on 0 to 5% of the total surface of said disk is between -1.5 and -2.5, and +1.5 to +2.5, and in that the potential on no more than 1% of the total surface of said disk is less than -2.5 kV and more than +2.5 kV. The potential measurements are carried out by means of a Monroe probe at a distance of 3.5 mm from the surface of the disk, the scanning region is in each case 12 cm in the X- and Y-direction, and in each case in steps of 2 mm in the X- and in the Y-directions.