| 摘要 |
PURPOSE:To prevent an occurrence of a gear mark, a transfer mark, a release mark, and the like to produce a polycarbonate sheet having a superior transparency and a thickness less than 3mm by a method wherein surface temperatures of a pair of polishing rolls used in a cooling process are kept within a specific temperature range. CONSTITUTION:A sheet material 11 extruded from an extruder die 1 is supplied to a pair of polishing rolls consisting of a first roll 2 and a second roll 3. After being pressurized and cooled by being clamped between the polishing rolls, the sheet material 11 is fed to a succeeding device 4 through the second roll to be finished as a polycarbonate sheet. At this time, the surface temperature of the first roll 2 is controlled to 80-120 deg.C, and the surface temperature of the second roll 3 is controlled to 100-140 deg.C. By cooling the material using the first roll 2 and the second roll 3 controlled under these temperature condition, the produced polycarbonate sheet has a good surface state and a superior transparency. |
