| 摘要 |
PROBLEM TO BE SOLVED: To prepare a high mol.wt. polyolefin film which has excellent mechanical strengths and a good balance between physical properties in the mechanical direction and physical properties in its orthogonal direction, in which highly transparent portions having excellent transparency are disposed, and which permits the free formation of patterns by the difference of transparency, and to provide a method for producing the film. SOLUTION: This high mol.wt. polyolefin film is characterized by having an intrinsic viscosity [η] of >=4 dl/g, a difference of >=10% between the haze value of a highly transparent portion and the haze value of an opaque portion, and partially formed transparent portions. The method for producing the high mol.wt. polyolefin film is characterized by heat-setting the pre-treated film of a high mol.wt. polyolefin having an intrinsic viscosity [η] of >=4 dl/g and obtained substantially without using a solvent and a plasticizer, thus obtaining the film having a thermal shrinkage rate of <10%, and then partially compressing and thermally treating the film under a pressure of <=0.1 MPa in a treatment range of the melting point of the film -30 deg.C to a lower temperature than the decomposition temperature of the film. |
