CHICAGO—At Engel North America's booth, an injection press with two injection units demonstrated Kortec Inc.'s multigate coinjection hot-runner technology.
The press was molding a test part with white polypropylene on the inside and dark PP outside.
Kortec of Gloucester, Mass., has developed a hot-runner coinjection system that keeps the core and skin materials separate until just before the resins enter the mold cavities, through special nozzles. Moving coinjection from the machine into the mold, Kortec said, allows the use of a two-color molding machine instead of a specially dedicated coinjection machine running cold sprue and runner molds.
Interest is growing in coinjection, which can encapsulate scrap inside a skin layer of virgin resin, Kortec President Paul Swenson said in an interview at Engel's booth at NPE in Chicago.
Kortec engineers designed the system for any single-cavity or multicavity mold.
Swenson was a founder of Kona Corp., which makes hot-runner systems in Gloucester. He started Kortec 11/2 years ago.