| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a production method of a stretched film by which a film can be appropriately heated and stretched in the process of producing a stretched film by heating and stretching the film, and a stretched film excellent in productivity and qualities can be obtained.SOLUTION: The production method of a stretched film includes steps of forming a composite film having a center part made and end parts in a width direction of the film, made of a thermoplastic resin different from a thermoplastic resin constituting the center part, by melting and melt-extrusion using a molding die; and heating and stretching the composite film at least in one direction to produce a stretched film. The composite film is formed in such a manner that a ratio [t/t] is 0.75 or more, where tis a minimum thickness in a boundary part formed between an inner region located inside in the width direction of the composite film and an outer region located outside in the width direction of the composite film; and tis an average thickness in the inner region.</p> |
