Incremental progress in barrier package design has been the case for years, but automation systems manufacturer Waldorf Technik believes it may have made a major leap forward with two new technologies. Working with co-injection systems specialist Kortec (Ipswich, MA) on the first, the firms have developed an injection molding system and Q/A equipment allowing for high-volume molding of polypropylene containers with an EVOH barrier in which the barrier layer's consistency can be 100% verified in-line.
EVOH, a copolymer of ethylene and vinyl alcohol, is often used as a barrier material to prevent oxygen ingression and CO2 egress.
The molding process developed by Waldorf and Kortec has been optimized for high volume packaging applications, for instance molding with a 32-or 64-cavity stack mold. Waldorf reports that multi-material injection of the retortable thin 3-layer structures (PP-EVOH-PP), plus tie layers, is repeatable and does not negatively affect cycle times....