Method and apparatus for making products from polymer wood fiber composite

Abstract

A method and apparatus for making products from polymer wood fiber composite is described. The method includes the steps of providing a extruder having two counter-rotating non-intermeshing screws, supplying to the extruder fiber material and polymer material, mixing and heating the fiber material and polymer material in the extruder for form a mixture, removing the mixture from the extruder and placing the mixture in a press, and compression molding the mixture in the press to form the product.

1 . A method of manufacturing a fiber polymer composite product in a continuous process, comprising the steps of: 
 providing a extruder have two counter-rotating non-self-wiping screws;    supplying to the extruder fiber material and polymer material;    mixing and heating the fiber material and polymer material in the extruder to form a mixture;    removing the mixture from the extruder and placing the mixture in a press; and    compression molding the mixture in the press to form the product.    
   
   
       2 . The method of  claim 1 , comprising the additional step of removing moisture from the fiber material in the extruder while mixing and heating the mixture.  
   
   
       3 . The method of  claim 1 , wherein the fiber material and the polymer material are separately supplied to the extruder.  
   
   
       4 . The method of  claim 3 , wherein the fiber material and the polymer material are supplied to the extruder through the same feed.  
   
   
       5 . The method of  claim 1 , wherein the step of providing an extruder having two counter-rotating non-self-wiping screws comprises providing an extruder having screws of a certain diameter, and wherein the fiber material contains particles as large in length as the diameter of the screws.  
   
   
       6 . The method of  claim 1 , wherein the fiber material is wood fiber material.  
   
   
       7 . The method of  claim 1 , wherein the fiber material and polymer material mixture is heated in the extruder to a temperature of between about 300° F. and about 400° F.  
   
   
       8 . The method of  claim 1 , wherein the fiber material and polymer material mixture is removed from the extruder and placed in the compression molding machine before it has had cooled more than about 50° F.  
   
   
       9 . A method of manufacturing a fiber composite product in a continuous process, comprising the steps of: 
 providing an extruder having two counter-rotating non-self-wiping screws each having a certain diameter;    supplying to the extruder fiber material having fibers of a length as large as the diameter of the screws;    mixing and heating the fiber material in the extruder to form a mixture; and    removing the mixture from the extruder.    
   
   
       10 . A product according to  claim 9 , wherein the fiber material is wood.  
   
   
       11 . A product made by a process of mixing and heating a mixture of polymer and fiber material in an extruder followed by compressing molding the mixture, the product having a specific gravity of between 0.85 and 1.05, a tensile strength between 1015 psi and 1710 psi.  
   
   
       12 . A product according to  claim 11 , wherein the fiber material is wood.  
   
   
       13 . Apparatus for the manufacture of polymer fiber composite products, comprising: 
 an extruder having twin counter-rotating non-self-wiping screws;    a receptacle for receiving a quantity of heated mixture from the extruder; and    a compression molding machine for applying pressure to a quantity of material to mold the mixture into a finished product.    
   
   
       14 . Apparatus for the manufacture of polymer fiber composite products according to  claim 13 , comprising in addition a material handling system for moving the receptacle from the extruder to the compression molding machine and from the compression molding machine.  
   
   
       15 . Apparatus for the manufacture of polymer fiber composite products according to  claim 13 , wherein the extruder includes vents for removing moisture from mixture therein.