| 摘要 |
PURPOSE:To obtain a sheet or a film showing prominent transparency in a wide thickness range by a method wherein a sheet type material, extruded from a T-die, is cooled by cooling agent from the non-contacting surface side to a cooling roll while a time whereat the material is contacted with the cooling roll to a time whereat a frost line is generated. CONSTITUTION:A molten sheet, extruded from a T-die 1, is cooled by first and second cooling rolls 2, 3 and is taken up to a take-up machine. A cooling tank 4 is provided at the non-contacting surface side of the molten sheet to the first cooling roll and cold water 6 is circulated by a refrigerating pump 5. The cold water cools the sheet at a place before a front line 7 after the molten sheet is contacted with the first cooling roll. The crystalline polyolefin resin sheet, thus manufactured, is prominent in the transparency thereof and is utilized as a transparent packing material for food, cosmetics, medicines or the like. |
