| 摘要 |
PURPOSE:To obtain a molded body, the expansion ratio of which is high and the surface smoothness of which is remarkably favorable, by a method wherein expandable resin is covered with non-expandable or low expandable resin in the same mold. CONSTITUTION:Flow paths 1 and 2 of expandable resin extruded from an extruder A communicate with the flow path 6 of a mold C rectilinearly. Flow paths 3-5 of non-expandable or low expandable resin extruded from an extruder B communicate with the flow paths 2 and 6 so as to meet each other at right angles. Further, screws 7 and 8, breaker plates 9 and 10 and a flow stopper 11 are respectively provided in the extruders. The expandable resin, which is extruded from the extruder A and passed through the flow path 2, and the non-expandable or low expandable resin passed through the flow path 5 and reaches the meting point of the resins so as to cover the outer peripheral surface of the expandable resin and finally extruded through the flow path 6 in the air. The cross-sectional area of the flow path 6 of the mold C, through which molten resin prepared by the expandable resin covered with the non-expandable or low expandable resin, is set to be 90% or less of the sum of respective cross-sectional areas of the flow path 2 of the extruder A and of the allow path 5 of the extruder B just before the position meeting with said flow path 2. |
