| 摘要 |
PROBLEM TO BE SOLVED: To provide an extruding die for a hollow cylindrical body of a high foaming ratio and a foaming extrusion molding device, which can effectively suppress the generation of a corrugation with a simple constitution. SOLUTION: A high shearing force loaded onto the part of a molten resin coming into contact with the surface of a middle stream part 46 and an inner pressure reduced part 50 can be relieved and the generation of the corrugation can be effectively suppressed by making the extrusion distance of the molten resin in its middle stream part 46 and inner pressure reduced part 50 2-30 mm while suppressing a breaking of foams. Also, the generation of the corrugation can be suppressed by applying a sand blast treatment with a sand of 500-3,000 mesh to respective surfaces mutually opposed to the middle stream part 46 and inner pressure reduced part 50. Additionally, the corrugation generated on the way of extrusion can be eliminated by applying the sand blast treatment and a fluororesin coating treatment alternately to respective surfaces mutually opposed to a downstream part 47 and a conical part 54 toward the downstream side in the extrusion direction. COPYRIGHT: (C)2007,JPO&INPIT |
