METHOD AND APPARATUS FOR THE PREPARATION OF PLASTIC ARTICLES BY EXTRUSION

摘要

1429064 Tubular film extrusion DOW CHEMICAL CO 27 Sept 1973 [2 Oct 1972] 45362/73 Heading B5B A tubular plastic film is melt extruded from die 14 (Fig. 1) through annular orifice 17 and passed whilst still softened over gas bearing 20, inside the tube, and over a cylindrical mandrel 25 which is maintained at a temperature below the thermoplastic temperature of the tube. The gas bearing supplies gas at a temperature less than that of the thermoplastic temperature of the tube. This bearing may be immediately followed by a tube positioning means 33 which issues gas in an inwardly flowing radial direction so as to contact the tube with the mandrel. Polyethylene is specifically mentioned among a comprehensive list of suitable extrudable film forming resins.