| 摘要 |
PROBLEM TO BE SOLVED: To provide a biaxially oriented polypropylene film which is improved in strength and heat resistance in comparison with a conventional biaxially oriented polypropylene film. SOLUTION: In a method for producing an oriented propylene film, when a propylene film or sheet is tenter-oriented, the strength of a part gripped by a tenter clip of both ends of its long length is made larger than that of the other part, and tenter-orienting is carried out. To both ends of the propylene film or sheet, a narrow film having a tensile modulus of elasticity higher than that of the propylene film or sheet is pressed, and the pressed part of the narrow film is gripped by the tenter clip and tenter-oriented. COPYRIGHT: (C)2009,JPO&INPIT |
