| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a biaxially oriented saponified ethylene-vinyl acetate copolymer film which can control bowing strain during transverse orientation by a tenter type transversely stretching machine and develop uniform physical properties in the transverse direction in a sequential biaxial orientation method. SOLUTION: The method includes a longitudinally stretching process in which a substantially amorphous unoriented saponified ethylene-vinyl acetate copolymer film is stretched longitudinally in a draw ratio of 2.5-5.0 at a specified temperature by a roll type longitudinally stretching machine, a transversely stretching process in which the film, with its both end parts grasped by the tenter clips of a tenter type transversely stretching machine, is stretched under specified conditions, and a heat treatment process in which the film, with its both end parts grasped by the tenter clips, is heat-treated at a specified temperature for at least 3 s.
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