POLYMER FILM FILM ROLL AND KNURLING APPLYING ROLLER

摘要

The film production apparatus produces a strip-shaped polymer film. The knurling imparting device on the downstream side of the film producing apparatus imparts knurling to the side of the polymer film. The knurling-imparted polymer film is wrapped around a core to form a film roll. Knurling has convex portions protruding from the surface of the polymer film. The convex portion has a plurality of ridgelines and apexes. Vertices are formed by the intersection of ridges and ridges. Knurling is formed on the ear portion so that the sum of the ridge lengths per unit area is equal to or greater than a predetermined value.