CONTACTLESS KNURLING PROCESS FOR WINDING OF HIGH MODULUS THERMOPLASTIC FILMS

摘要

A contactless method for knurling thermoplastic film to improve its winding characteristics is disclosed. A preferred embodiment employs an ink jet printer to intermittently deposit ink upon at least one margin of the moving film surface. A second preferred embodiment employs a laser to intermittently modify at least one margin of the moving film surface. The invention eliminates the problem of stress gradient during web transport prior to winding which is inherent in contact knurling and particularly troublesome in the manufacture of high modulus, relatively thin thermoplastic films.