| 摘要 |
PURPOSE:To easily obtain a sheet having required double refractivity and excellent heat resistance and to reduce the irregularity of double refractivity by rolling a polycarbonate sheet within a predetermined temp. range to quench the rolled one. CONSTITUTION:A polycarbonate sheet is rolled at a draft of 10-25% within a temp. range of 160-185 deg.C and subsequently quenched to fix molecular orientation. That is, in a rolling apparatus, stainless belts 1, 1 each having a mirror surface are trained over a pair of upper and lower press rolls 2, 2 and guide rolls 3, 3 and cooling rolls 4, 4 for cooling the polycarbonate sheet rolled while held between the belts 1, 1 and moved along the surfaces thereof are mounted in front of the press rolls 2, 2. The sheet 11 unwound from an unwinding reel 5 is rolled by the press rolls 2, 2 through the belts 1, 1 and quenched by the cooling rolls 4, 4 to be taken up by a take-up reel 6. |
