| 摘要 |
PURPOSE:To obtain an optical disc substrate with less warpage deformation and excellent warpage and plane deflexion properties by measuring the plane deflexion rate and tilt of the substrate in changing the molding conditions, and distinguishing the influence of the molding conditions exerted in warpage and plane deflexion properties. CONSTITUTION:Mold is carried out under the condition of 80-120 deg.C in the mold temperature, 300-380 deg.C in the temperature of an injection cylinder, 35MPa or less in the dwelling force, and 0.2 seconds or more in the gate cut waiting time. When the dwelling force and the dwelling time are great, and the gate cut waiting time is short, the counter flow of resin is prevented, and the resin is cured in the state with high pressure, so that, there may occur warpage as the substrate is taken out, and then the pressure is released therefrom. Thus, it is required that the dwelling pressure is 35MPa or less, the dwelling time is 0.5 seconds or shorter, and the gate cut waiting time is 0.2 seconds or longer as the condition range of less warpage deformation. |
