MANUFACTURE OF RESIN DOUBLE LAYERED TUBE

摘要

PROBLEM TO BE SOLVED: To reinforce axially and peripherally by a method wherein thermoplastic resins are doubly and tubularly extrusion-molded so as to axially stretch the resin, of which an outer tube is made, and peripherally stretch the resin, of which an inner tube is made so as to laminate the outer tube and the inner tube to each other by bonding them together. SOLUTION: An exterior appearance forming resin 1 and an inner tube forming resin 2 are concentrically extruded from an extrusion mold 3 into a double tube and then heated up to a stretching temperature at a temperature controlling mold 4. Next, the outer diameter of the resultant tube is regulated by a sizing die 5 and, at the same time, is diametrically reduced and finally the tube is stretched axially by a take-up device 6. Similarly, the inner tube forming resin 2 is heated up to the stretching temperature by being supplied from the extrusion mold 3 to the temperature controlling mold 4 so as to diametrically stretched by a gradually and diametrically enlarging mold 7. Further, over the region ranging from the extrusion mold 3 to the temperature controlling mold 4, a hot melt type adhesive 8 is dripped from an adhesive 8 dripping port on the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube so as to adhere to both the surfaces. Finally, both the tubes are integrally laminated and cooled down by a cooling device 9 to the normal temperature.