| 摘要 |
METHOD AND APPARATUS FOR THE EXTRUSION OF TUBULAR THERMOPLASTIC FILM The present invention relates to a method and apparatus for the extrusion of tubular thermoplastic film which comprises extruding a melt of thermoplastic material through an annular orifice to form a bubble or tube and while the tube is still in a semi-molten condition, passing the tube through an extrusion cooling and shaping means having a plurality of multi-perforated air rings shaped in congruance to the desired shape of the inflating tube. This method allows increased production speeds and minimized guage variation while maintaining bubble stability. |
