A die system and a process for extruding cellular, foamed, cellulosic fibrous-polymer composition

摘要

The present invention is directed to a device for the production of a cellular wood plastic composite material comprised of an orifice that conducts the composite material from the adapter of the extruder to the transition die plate in such a manner that a uniform flow of material reaches the transition die plate; a transition die plate that further directs the flow of material to a flow restriction die plate in a manner ensuring that equal amounts of material are delivered to all areas of the flow restriction die plate; a flow restriction die plate that provides sufficient resistance to material flow to increase the melt pressure of the portion of the material that is upstream in relation to the flow restriction die plate and controls the temperature increase caused by this restriction by dividing the flow into numerous suitably sized and shaped streams; a compression die plate that fuses the separate streams issuing from the flow restriction die plate into a single stream of material and maintains the melt pressure at a level which will prevent premature development of cells in the material; a shaping die plate that is designed to shape the material in such a way that the fully expanded material will approximate the shape of the desired profile and to control the rate of cell development and expansion so that large numbers of uniform cells are produced.