Method and apparatus for forming composite material and composite material therefrom

Abstract

A system and method for extruding composite material and the composite material therefrom. The composite material consists of a filler mixed with a binding agent. The composite material is extruded as billets with enhanced physical properties, such as colour, texture, electrical conductivity and fire retardancy, and contains a dispersion pattern of the filler material. A system and method are also provided for drawing the composite material through a die and a composite material produced thereby. The drawn composite material exhibits a density reduction over the density of the starting material and enhanced physical properties. A particularly useful tongue and groove arrangement are also provided for joining adjacent strips of a composite material made according to the extrusion process.

1 . A composite material comprising: 
 an oriented polymer; and    a particulate filler dispersed throughout said oriented polymer,    wherein said composite material has a reduced density which is less than the combined masses of the oriented polymer and particulate filler divided by their combined respective volumes.    
     
     
         2 . The composite material of  claim 1  wherein: 
 said oriented polymer is a plastic; and    said particulate filler is selected from the group consisting of wood, slate, talc, vermiculite and mica.    
     
     
         3 . The composite material of  claim 2  wherein: 
 said oriented polymer is selected from the group consisting of polypropylene, polyethylene and polyvinyl chloride.    
     
     
         4 . The composite material of  claim 1  where: 
 said oriented polymer is present in an amount of from 95 to 60 percent by weight as compared to said particulate filler.    
     
     
         5 . The composite material of  claim 4  wherein: 
 said oriented polymer is selected from the group consisting of polypropylene, polyethylene, and polyvinyl chloride.    
     
     
         6 . The composite material of  claim 4  wherein: 
 said particulate filler is selected from the group consisting of wood, slate, talc, vermiculite and mica.    
     
     
         7 . The composite material of  claim 4  wherein: 
 said oriented polymer is polypropylene; and    said particulate filler is wood sawdust.    
     
     
         8 . The composite material of  claim 7  wherein: 
 said sawdust has a particle size of about 60 mesh.    
     
     
         9 . The composite material of  claim 8  wherein: 
 said particulate filler is present in an amount of from 20% to 30% by weight as compared to said oriented polymer.    
     
     
         20 . An oriented composite material as produced by a process comprising the steps of: 
 i) combining an extrudable polymer with a cellulose based particulate filler to form a starting material;    ii) heating and extruding said starting material into a first column;    iii) adjusting the temperature of said first column to a drawing temperature;    iv) presenting said first column to a drawing die and causing said first column to exit said drawing die in a second column having a cross-sectional area less than that of said first column;    v) applying a pulling force to said second column to draw said first column through said drawing die at a rate sufficient to cause orientation of said polymer and to cause said second column to diminish in density to form said composite material.    
     
     
         21 . A composite material comprising: 
 a filler for enhancing the physical properties of said composite material; and a binding agent, mixed with said filler, for permitting extrusion of billet of said composite material in a plastic extrusion process to provide a predetermined dispersion pattern of said filler in said composite material.    
     
     
         22 . The composite material of  claim 21  wherein said filler is a natural fiber.  
     
     
         23 . The composite material of  claim 21  wherein said filler is a synthetic fiber.  
     
     
         24 . The composite material of  claim 21  wherein said binding agent is a polymer.  
     
     
         25 . A composite material comprising a particulate material dispersed in an oriented polymer.  
     
     
         26 . The composite material of  claim 25  wherein said particulate material is wood sawdust having a particle size of about 60 mesh; 
 said oriented polymer is polyethylene; and    said oriented polymer forms from 60% to 95% by weight of said composite material.