HIGH-STRENGTH HIGH-MOLECULAR WEIGHT POLYOLEFIN FILM EXCELLENT IN TRANSPARENCY AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To produce a high-strength high-molecular weight polyolefin film having good transparency and excellent in balance of physical properties between the mechanical axial direction and the direction intersecting the direction at right angles and to provide a method for producing the high-molecular weight polyolefin film by which the film can be produced with good productivity. SOLUTION: This high-molecular weight polyolefin film has (1) >=4 dL/g intrinsic viscosity, (2) <=200μm thickness, (3) a haze [H (%)] satisfying the relationship of H<=10+(t/3) between the H and the thickness [t(μm)] and (4) >=50 MPa tensile strength in the mechanical axial direction and the direction intersecting the direction at right angles. The method for producing the high- molecular weight polyolefin film comprises compression heat-treating a film prior to the treatment comprising a high-molecular weight polyolefin having >=4 dL/g intrinsic viscosity and obtained without substantially using a solvent or a plasticizer under >=0.1 MPa pressure at a temperature ranging from the melting point of the film prior to the treatment -30 deg.C to the highly oriented melting point +5 deg.C.