Apparatus for producing perforated film

Abstract(summary):

A process and apparatus for the manufacture of thermoplastic sheet having elliptical perforations, the process including placing a thermoplastic sheet into contact with a continuously rotating molding element having a series of elliptical holes therein in which the major axis of the elliptical holes is oriented parallel to the direction in which the molding element is rotating, subjecting a surface of the thermoplastic sheet to the action of a fluid pressure differential to cause the material to flow into the elliptical holes of the molding element while maintaining the pressure differential to effect rupturing of the thermoplastic sheet and the formation of elliptical holes in the sheet, and continuously removing the molded portions of the thermoplastic sheet from the molding element. The apparatus for the manufacture of perforated thermoplastic sheet products having elliptical holes therein includes a rotating molding element having a series of elliptical holes therein in which the major axis of the ellipse is oriented parallel to the direction in which the molding element is rotating.