| 摘要 |
PURPOSE:To obtain a base sheet with a small and uniform angle of warpage and a small fluctuation of the angle of warpage in the peripheral direction by a method wherein after a disc-shaped optical disc base sheet is injection- molded, the molding is forcibly cooled between taking-out of a mold and storage in a stockyard. CONSTITUTION:A disc-shaped base sheet 7 is injection-molded by using a transparent resin material. The base sheet 7 is taken out of a mold by means of a suction plate of a robot 8 and is forwarded to a stockyard such as a stock pole 9 as it is. Forced cooling is performed during transfer. It is pref. for cooling that air at room temp. is blown on the base sheet 7 and for example, it is pref. that both faces of the base sheet 7 is cooled simultaneously by means of an air blower 10, to cool 20-80 deg.C lower than the softening temp. of the resin before it is stored in the stockyard. It is possible by this forced cooling that the angle of warpage of the stocked base sheet 7 is made approximately uniform and the fluctuation of the angle in the peripheral direction is made small. |
