| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an extrusion molding die capable of controlling the flow of thermoplastic resin and stabilizing the quality of a seamless product. <P>SOLUTION: In the extrusion molding die, a shaft-like mandrel 5 having a circumferential surface 13 is inserted to a cylindrical die body to guide the thermoplastic resin supplied to a gap between the mandrel 5 and die body in the extrusion direction toward the other end 13 from one end 11 of the mandrel 5. On the circumferential surface 3 of the mandrel 5, a recessed expanding part 15, an inlet part 17 and a plurality of spiral grooves 19 are formed. The recessed expanding part 15 is such a crescent-shaped recessed part that edge parts 27 of both sides are extended to directions opposite to each other. The spiral groove 19 has a position separated in the extrusion direction from the recessed expanding part 15 of the circumferential surface 3 of the mandrel 5 as a starting edge 35. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
