초록 ▼

A multiple-plastic stream co-extruder as for injection-molding cavities, in which the extruder is internally provided therewithin and therealong with a restrictor or throttle pin, rod or element that forces combined plastic material streams, formed with an interior core stream encased in outer and i

A multiple-plastic stream co-extruder as for injection-molding cavities, in which the extruder is internally provided therewithin and therealong with a restrictor or throttle pin, rod or element that forces combined plastic material streams, formed with an interior core stream encased in outer and inner stream layers, into corresponding concentric annular flow stream layers that are ultimately split transversely in opposite directions into a cavity gated to the extruder, and with the core stream at a region of zero gradient in the transverse flow velocity profile within the extruder and cavity.

대표청구항 ▼

[ What is claimed is:] [1.] Apparatus for co-extruding multiple plastic materials as for injecting through a gate region into a mold cavity to produce a molded product, having, in combination, plastic material flowing stream sources; means for combining streams of such flowing plastic materials with

[ What is claimed is:] [1.] Apparatus for co-extruding multiple plastic materials as for injecting through a gate region into a mold cavity to produce a molded product, having, in combination, plastic material flowing stream sources; means for combining streams of such flowing plastic materials with at least one interior stream that is to serve as an interior core of a resulting molded plastic product within interior and outer streams of plastic material to serve as covering plastic material layers; a longitudinally extending hollow extruder connected to the combining means to receive the outer and interior streams; flow restrictor disposed within and along the extruder to force the combined streams to flow along concentric annular flow paths within and along a longitudinally extending tubular extruder to the cavity gate region, with the annular interior core stream encased by inner and outer annular covering plastic material stream layers; the mold cavity at the gate region being shaped for splitting the concentric annular streams along opposite transverse directions to inject into corresponding opposite transverse sections of the cavity.