MOLD DIE FOR COMPOSITE PLASTIC COVERING

摘要

PURPOSE:To obtain a mold die capable of giving a composite plastic covering of uniform thickness by providing a spiral groove on the inner surface of an annular space portion formed by combining cylinders. CONSTITUTION:Spiral grooves 12 and 13 are provided on the inner surfaces of annular pathways 9 and 11, and molten plastics supplied from supply ports 8 and 10 are orderly extruded along the grooves 12 and 13. Covering layers of plastics A and B are laminated over all circumference on the outer surface of the tube 2 from an annular discharge port 15 at the confluence 14 provided on the tip portion of the mold die 1 and a composite covering layer of practically uniform thickness is extruded.