The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 17, 1999
Filed:
Aug. 29, 1997
Brent W English, Barneveld, WI (US);
Kevin P Gohr, Sheboygan, WI (US);
Other;
Abstract
A wood-plastic composite material is produced in a twin screw extruder with parallel intermeshing segmented screws. The screw segments are positioned on two spline shafts and perform the various required functions of mixing, deaerating and removal of moisture followed by extrusion. A polymer is fed to the main throat of the extruder where the plastic is conveyed along a barrel formed by the case of the extruder. Cellulosic fiber is positively fed into the extruder approximately one-quarter of the way down the extruder barrel by a twin screw side stuffer. A vent is provided for entrained air in the cellulosic material to escape. The molten mixture of polymer and cellulosic material is then conveyed to a devolatilization area having a first atmosphere devolatilization area and a second vacuum devolatilization area separated by a melt seal. A pumping section raises the pressure of the mixture of polymer and cellulosic material to between 1,000 and 6,000 psi which is then extruded through a multiplicity of small holes and separated into individual pellets by a four bladed rotating knife. Calcium carbonate, talc, or other mineral is blown onto the pellets as they are formed to prevent them from sticking to each other. The pellets are cooled to room temperature by a fluidized air bed which rapidly cools the pellets without immersing them in water.