Injection molding device for a laminated synthetic resin bottle

摘要

INJECTION MOLDING DEVICE FOR A LAMINATED SYNTHETIC RESIN Abstract The present application discloses an injection molding device to be used to injection mold a laminated preform, which is in a test-tube shape, has substrate layers of a main resin and at least an intermediate layer, and is used in biaxial drawing and blow molding, said injection molding device comprising two resin feeders to feed the main resin and at least a resin for forming an intermediate layer, a multi-nozzle section (11) in which to laminate the main resin with the intermediate layer resin, and a mold (1) for molding the preform, wherein the multi nozzle section (11) comprises at least three layer forming flow channels; a cylindrical inner flow channel (15) and a cylindrical outer flow channel (17) to form the substrate layers of the main resin; and a cylindrical middle flow channel (16) located between the inner flow channel (15) and the outer flow channel (17) to form the intermediate layer, and a joined flow channel (19) disposed downstream of at least three layer forming flow channels and by way of a confluence (18) where molten resins join after having flowed through respective layer-forming flow channels, and wherein at some points ranging from a given position along the middle flow channel (16) to the confluence (18), a plural number of vertical blocking rib pieces (16R) are disposed in parallel in the circumferential direction so as to cross the middle flow channel (16) and to divide the flow through the middle channel (16) into multiple streams along the circumferential direction.