| 摘要 |
PROBLEM TO BE SOLVED: To provide a direct blow-molded vessel having protrusion of excellent form accuracy on an inner periphery. SOLUTION: A direct blow molding apparatus 1 has a parison forming die 8 extruding molten thermoplastic resin 3 into a tubular shape to form a parison 4. The parison forming die 8 includes a mandrel 18 serving as a shaft mold when extruding the molten thermoplastic resin 3 into the tubular shape, and a parison forming die body 20 surrounding the periphery of the mandrel 18 by providing an annular path 19. In an outer periphery 35 of the mandrel 18A, a recessed groove 36 for forming the protrusion 407 on the inner periphery 406 of the parison 4 is formed which extends in the axial direction A1 of the mandrel 18. A first air path 22 penetrating through the inside of the mandrel 18 and for blowing a gas stream into the parison 4 via the recessed groove 36 is formed in the mandrel 18. Consequently, the molten thermoplastic resin 3 easily flows through the recessed groove 36. COPYRIGHT: (C)2010,JPO&INPIT |
