| 摘要 |
PROBLEM TO BE SOLVED: To perform simply switching of molding with and without an additive without impairing quality due to inclusion of a retention degradation polymer. SOLUTION: The apparatus for extrusion molding a plastic couples a discharge port of a first stage extruder 41 to a supply port of a second stage extruder 42 by a channel 53 for sending a base polymer. In this case, pouring passages 54, 55 for an additive-filled polymer are coupled to the channel 53. Then, three-way switching valves 51, 52 having ram valves are respectively installed at the passages 54, 55, and can be switched to a supply side 61 to the channel 53 and to a discharge side 53 for discharging out of a system. The ram valve reversely feeds the base polymer from the channel 53 toward the three-way switching valves to be discharged out of the system during feeding only the polymer.
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