PROCESS FOR PRODUCING NONSTRETCHED FILM, PROCESS FOR PRODUCING RESIN COATED METAL PLATE, AND APPARATUS FOR PRODUCING NONSTRETCHED FILM

摘要

This invention provides a process for producing a nonstretched film formed of a thermoplastic resin, and an apparatus for producing a nonstretched film formed of a thermoplastic resin. In this production process, a thermoplastic resin A to be formed into a nonstretched film, and another thermoplastic resin B other than the thermoplastic resin A are heat melted separately from each other and are led respectively to both ends of an extrusion T die, followed by delivery of the melts in such a manner that the thermoplastic resin B coexists on both sides of the heat melted thermoplastic resin A, whereby the assembly is extruded onto a casting roll to form a nonstretched film comprising the thermoplastic resin B provided on both sides of the thermoplastic resin A. The sectional form of a hole (B3a, B3b) formed by boring on both sides of the lower part of a tube for supplying the thermoplastic resin A is such that an approximately half of the upper side of an elliptical shape in which the major axis is parallel to the flow direction of the heat melted resin and the minor axis is normal to the flow direction of the heat melted resin is closed, and the closed part (B4) has a projection (B5), whereby concave-convex streaks are formed at the boundary between the thermoplastic resin A and the thermoplastic resin B.