Patent ID: 6380272
Filing Date: 2002-04-30
Classification: B29B,B29C,B29K,B29L

Abstract:
A manufacturing method for making structural elements suitable for doors frames, sealed strips or other structural members from foamed plastic resin/wood flour composites comprising the step of:combining powders composed of polyvinyl chloride powder, non-resin impregnated wood flour having a fiber length below 0.6 millimeters and a diameters not exceeding 0.6 millimeters, powdered stabilization agents, powdered foaming agents, powdered gelatinization agents and powdered lubricanting agents; placing said combined powders in a thermal stirring mixer at a temperature from room temperature and stirring at a low speed to blend said combined powders, followed by stirring at a higher speed to disperse said powders in a homogeneous blend of said powders and to raise the temperature of said homogeneous blend of said powders to approximately 100 degrees centigrade; placing said homogeneous blend of said powders in a cold stirring mixer to reduce the temperature from approximately 100 to 40 degrees centigrade by mixing at low speed to dissipate the heat in said homogeneous blend of said powders to prevent agglomeration of said homogeneous blend of said powders to form a resulting feed stock for an extrusion machine; and adding said resulting feed stock to an extrusion machine and extruding foamed structural shapes therefrom having a density between 0.5 and 1.1 gram/cubic centimeters.