| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a biaxially stretched film of low heat absorption in which the occurrence of chips is suppressed even when the edge parts of the biaxially oriented white film high in light reflectance and concealment properties are cut in a tenter, and no foreign substance adhering to the film exists. SOLUTION: In the method for manufacturing the biaxially stretched film, at least two layers of a layer (A) made of a thermoplastic resin containing a small amount of inactive particles and a layer (B) made of a thermoplastic resin containing 20-80 wt.% of the inactive particles are laminated alternately and extruded from a die to obtain an unstretched film in which the layer (B) is exposed to at least one side of it, after that, when the unstretched film is stretched, and its edge parts are cut by a blade in the tenter to carry out vertical relaxation heat treatment, both edge parts of the film are made a single layer of the layer A alone and cut by the blade in the tenter, and the multilayer part of the film taken out from the tenter is trimmed further to wind up a product part. COPYRIGHT: (C)2011,JPO&INPIT |
