Methods and systems for the preparation of molded plastic articles having a structural barrier layer

A method of co-extruding a plurality of polymeric plastic material streams to produce a resulting molded plastic article, the method comprising the steps of:

• forming a combined polymeric plastic stream in an injection nozzle, the combined stream comprising an interior core stream of a first polymeric material encased by an inner stream of a second polymeric material and an outer stream of the second polymeric material;
• injecting the combined stream into a mold cavity;
• and
• creating one or more controlled pulsations in a thickness of the interior core stream in the cavity such that a first portion of an outer edge of the interior core stream flows beyond a second portion of the outer edge of the interior core stream thereby forming a plurality of cohesion members, wherein at least a first one of the plurality of cohesion members physically interlocks an interior layer of the resulting molded plastic article formed from the interior core stream with an inner layer of the resulting molded plastic article formed from the inner stream, and wherein at least a second one of the plurality of cohesion members physically interlocks the interior layer of the resulting molding plastic article formed from the interior core stream with an outer layer of the resulting molded plastic article formed from the outer stream.