EXTRUSION OF POLYURETHANE COMPOSITE MATERIALS
Methods of extruding polyurethane composite materials are described. One method includes introducing at least one polyol and inorganic filler to a first conveying section of the extruder, transferring the at least one polyol and inorganic filler to a first mixing section of an extruder, mixing the at least one polyol and the inorganic filler in the first mixing section, transferring the mixed at least one polyol and inorganic filler to a second conveying section of the extruder, introducing a di- or poly-isocyanate to the second conveying section, transferring the mixed at least one polyol and inorganic filler and the di- or poly-isocyanate to a second mixing section, mixing the mixed at least one polyol and inorganic filler with the di- or poly-isocyanate in the second mixing section of the extruder to provide a composite mixture, and transferring the composite mixture to an output end of the extruder. Other related methods are also described.
1 . A method of forming a polymeric composite material in an extruder, the method comprising:
introducing at least one polyol, a di- or poly-isocyanate, and inorganic filler to a first conveying section of the extruder, the first conveying section comprising one or more transport screws;
transferring the at least one polyol, the di- or poly-isocyanate, and the inorganic filler to a first mixing section of an extruder;
mixing the at least one polyol, the di- or poly-isocyanate and the inorganic filler in the first mixing section to producing a composite material, the first mixing section comprising a reverse screw; and
transferring the composite mixture to an output end of the extruder.
2 . The method of claim 1 , wherein the first mixing section comprises a lobal screw.
3 . The method of claim 1 , further comprising introducing fibrous material in the first conveying section and mixing the fibrous material with the at least one polyol, the di- or poly-isocyanate and the inorganic filler in the first mixing section.
4 . The method of claim 1 , further comprising mixing a catalyst with the at least one polyol, the di- or poly-isocyanate and the inorganic filler.
5 . The method of claim 2 , wherein the catalyst is mixed prior to the composite mixture exiting an output end of the extruder.
6 . The method of claim 5 , further comprising extruding the composite mixture through a die.