Patent ID: 6793861
Filing Date: 2004-09-21
Classification: B29C,B29K,C09D,Y10T

Abstract:
A process of forming an in-mold coated thermoplastic workpiece comprising the steps of:(a) injecting, using an injection high pressure, into a mold comprising a fixed mold half and a movable mold half, and which is maintained in a closed position under a clamping pressure, greater than said injection high pressure, a thermoplastic material which is at a temperature above its melt temperature, to fill at least about 75 percent of said mold; (b) continuing, using an injection pack pressure which is less than said injection high pressure, to inject said thermoplastic material which is at or above its melt temperature into said mold which is maintained in a closed position under said clamping pressure until said mold is filled to at least 99 percent of its capacity; (c) maintaining said thermoplastic material, as it cools, under a hold pressure, which is less an said injection pack pressure, in said closed mold, which is maintained under said clamping pressure, to form a workpiece; (d) injecting into said closed mold while maintained under said clamping pressure and immediately after the surface temperature of said thermoplastic forming said workpiece falls below a melt temperature, a predetermined amount of in-mold coating material to coat at least a portion of the surfaces of said workpiece; and (e) releasing said clamping pressure, opening said mold and removing said in-mold coated workpiece after said in-mold coating material has at least partially cured.