Method and apparatus for slitting thermoplastic films

Abstract

A method of slitting a continuous thermoplastic film comprises advancing the film longitudinally at a first speed along a peripheral surface of a roll rotating at a peripheral speed equal to or slightly greater than that of the film, and slitting the film while being advanced by pressing cutting edges of a rotating cutter against the peripheral surface of the roll. In order to prevent the cutting edges from being worn out and to form slits of uniform size and shape, the peripheral surface comprises an elastic layer of polymeric material, the cutting edges are heated above a temperature at which the film starts melting, the film and the elastic surface layer are cooled along their contacting surfaces with a cooling liquid, and the cutting edges are rotated at substantially the same peripheral speed as the roll. The invention also includes an apparatus for carrying out the method.

Dependencies are inferred from the claim text.