PREVENTIVE FILM FOR POLARIZING FILM AND PREVENTIVE FILM FOR RELEASABLE POLARIZING FILM, AND POLARIZING PLATE USING THEM

摘要

A preventive film for a polarizing film which comprises a non-oriented three-layer film comprising a polycarbonate film having a glass transition temperature of 100ringC or higher and, laminated on both surfaces thereof, polybutylene terephthalate films; a releasable preventive film for a polarizing film which comprises the three-layer film and, applied on the surface of the polybutylene terephthalate film side, a silicone based releasing agent; and a polarizing plate which has the preventive film for a polarizing film and the releasable preventive film for a polarizing film as uppermost surface layers of a polarizing film containing a polarizer. The preventive film for a polarizing film and the releasable preventive film for a polarizing film exhibit an extremely small double refraction and can be produced at a low cost, and the polarizing plate using these films allows the detection of optical defects with ease.