The invention relates to a composition comprising a
polymer and wood
fiber composite that can be used in the form of a linear extrudate or
thermoplastic pellet to manufacture structural members. The
polymer and wood
fiber composite structural members can be manufactured in an
extrusion process or an
injection molding process. The linear extrudate or pellet can have a cross-section of any arbitrary shape, or can be a regular geometric. The pellet can have a cross-section shape having a volume of at least about 12 mm3. Preferably the pellet is a right cylindrical pellet having a minimum
radius of about 1.5 mm and a minimum length of 1 mm weighing at least 14 mg. The invention also relates to an environmentally sensitive recycle of waste streams. The
polymer and wood
fiber composite contains an intentional recycle of a
waste stream comprising polymer flakes or particles or wood fiber. The
waste stream can comprises, in addition to polymer such as
polyvinyl chloride or wood fiber,
adhesive, paint,
preservative, or other chemical
stream common in the wood-window or door manufacturing process, or mixtures thereof. The initial mixing step before
extrusion of the
composite material insures substantial mixing and melt contact between molten polymer and wood fiber. The extruded pellet comprises a consistent proportion of polymer, wood fiber and water. During the
extrusion, water is removed intentionally to dry the material to a maximum
water content of less than about 10 wt-% based on the pellet weight. To make a
structural unit, the pellet is introduced into an extruder or injection molding apparatus wherein, under conditions of
temperature and pressure, the
composite pellet material is shaped into a useful cross-section. Alternatively, the extruded
thermoplastic mass, in the form of a elongated linear extrudate without a
pelletizing step, can be immediately directed after formation into an extruder or injection molding apparatus.