| 摘要 |
PURPOSE:To improve the transparency of a sheet without reducing the thermal formability of a polypropylene sheet. CONSTITUTION:Polypropylene is fusion-extruded on a cooling drum like a sheet, and after its cooling it is rolled between the rolls of the surface temperature of 100-120 deg.C at the rolling ratio of 1.1-1.4, whereby the globular crystal on the surface of the sheet is crushed and its transparency is made excellent. The sheet excellent in transparency may be obtained without using the special cooling method such as water cooling. Since the thermal formability of said sheet is not reduced, it is preferably used for the use of forming such as for PTP. |
