Patent ID: 6063325
Filing Date: 2000-05-16
Classification: B29B,B29C

Abstract:
A method of reducing uncontrolled flow of a molten polymer during the packing and cooling stage of an injection molding cycle, wherein a plurality of polymers are injected between a mold cavity and core for making a multilayer plastic article having upper and lower regions and a tapered region there between which decreases in wall thickness as it approaches the upper region, wherein during the molding cycle at least one first polymer is injected to form an exterior layer and at least one second polymer is injected to form an interior layer, and wherein the second polymer forms a flow front having a leading/trailing edge, the method comprising the step of:selecting the width of the tapered region, as defined between the mold cavity and core, such that the interior layer extends substantially up to the upper region at all points around the circumference and the second polymer does not reverse flow during the packing and cooling stage.