METHOD OF FEEDING COMPOSITE MOLTEN RESIN AND APPARATUS FOR FEEDING THE SAME

摘要

It is intended to feed a composite molten resin capable of easily produci ng a wide variety of multilayer preforms. In a main body of nozzle, at its e xtreme outside, a main-layer forming molten resin with circular flow channel circulates. Inside the extreme-outside circular flow channel, there is prov ided an outside vent where an outside flow channel of sublayer forming molte n resin converges. Inside an outside confluence channel, there is disposed a n inside vent where a circularly flowing shell-layer forming molten resin an d a core-layer forming molten resin flowing inside the shell layer join toge ther. The outside vent and the inside vent in this order are disposed from t he downstream side toward the upstream side in the direction of flow of molt en resin. Further, there are disposed an axial switch valve for opening and closing of the inside vent and a gear pump for intermittent discharge of sub layer forming molten resin.