| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of effectively manufacturing a biaxially stretched polyamide-based mixed resin laminated film roll enabling a smooth bag making work in a good yield by lamination. SOLUTION: The manufacturing method includes a melting-extruding-cooling process of obtaining an un-stretched sheet by melting a polyamide-based mixed resin, extruding it into a sheet form on a moving-cooling body surface and cooling the sheet, a biaxially stretching process of biaxially stretching the un-stretched sheet in vertical and lateral directions and a winding process of winding the biaxilly stretched film in a roll shape. In the melting-extruding-cooling process corona discharge in the streamer corona state is conducted between an electrode to which a high voltage of a direct current is applied and the molten polyamide-based mixed resin laminated sheet receives an electric charge sufficiently enough to make the laminated sheet tightly contact the moving-cooling body surface. Then, variation widths of physical properties such as a boiling water shrinkage ratio of the obtained film roll, an index of refraction thereof in respective thickness direction and the like are adjusted to be in respective predetermined ranges. COPYRIGHT: (C)2007,JPO&INPIT |
