| 摘要 |
PROBLEM TO BE SOLVED: To reduce deforming force received by a film layer from a winding end so as to improve planeness of a film at a core part by setting an angle of an end face over the front and rear faces of the film to the core surface into a specific range, and setting the thickness of the film into a specific range. SOLUTION: An angleθof a film end 5 to the core surface 1a in the winding end of an innermost layer film 2a brought into contact with a core 1 in a film roll is set to a range of about 5-85 deg., and the thickness of a film 2 is to be in a range of about 25-1000μm. The winding strength of the film roll is measured by a rubber hardness meter and set in a range of about 70-99 deg.. The core 1 is made of paper, paper impregnated with resin, plastic, glass epoxy or metal. As a result, the deformation of the film at a core part caused by the step difference of the film at the core part is hardly generated, and the planeness of the film after being pulled out is kept satisfactory.
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