Process for making composite polymer

Abstract

The method of making a pellet comprising wood pulp fiber and thermoplastic polymer, comprising extruding an extrudate comprising 10 to 50 weight % wood pulp fiber and 45 to 85 weight % thermoplastic polymer through a die, cutting a pellet from the extrudate, removing the pellet from the extrudate with water having a temperature less than the extrudate, filtering the pellet from the water. In one embodiment the wood pulp fiber in the pellet has a moisture content of 1% or less. In one embodiment the wood fiber does not swell.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . A method of making a pellet comprising wood pulp fiber and thermoplastic polymer, the method comprising:
 extruding an extrudate comprising 10 to 50 weight % wood pulp fiber and 45 to 85 weight % thermoplastic polymer through a die,   cutting a pellet from the extrudate,   removing the pellet from the extrudate with water having a temperature less than the extrudate, and   filtering the pellet from the water;   wherein the wood pulp fiber in the pellet has a moisture content of 1% or less.   
     
     
         2 . The method of  claim 1 , wherein the wood pulp fibers are bleached chemical wood pulp fibers. 
     
     
         3 . The method of  claim 1 , wherein the thermoplastic polymer is selected from the group consisting of biopolymers, polylactic acid, cellulose acetate, cellulose propionate, cellulose butyrate, polycarbonates, polyethylene terephthalate, polyolefins, polyethylene, high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, polystyrene, polystyrene copolymers, acrylonitrile-butadiene-styrene copolymer, styrene block copolymers, polyvinyl chloride, and recycled plastics. 
     
     
         4 . The method of  claim 1 , further comprising:
 cooling the water filtered from the pellet, and   recycling the water to the extrudate.   
     
     
         5 . The method of  claim 4 , wherein the wood pulp fibers are bleached chemical wood pulp fibers. 
     
     
         6 . The method of  claim 4 , wherein the thermoplastic polymer is selected from the group consisting of biopolymers, polylactic acid, cellulose acetate, cellulose propionate, cellulose butyrate, polycarbonates, polyethylene terephthalate, polyolefins, polyethylene, high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, polystyrene, polystyrene copolymers, acrylonitrile-butadiene-styrene copolymer, styrene block copolymers, polyvinyl chloride, and recycled plastics. 
     
     
         7 . The method of  claim 1 , further comprising pumping the extrudate to the die. 
     
     
         8 . The method of  claim 1 , wherein the extrudate comprises 20 to 40 weight % wood pulp fiber and 55 to 75 weight % thermoplastic polymer. 
     
     
         9 . The method of  claim 1 , wherein the wood pulp fiber does not swell. 
     
     
         10 . The method of  claim 9 , wherein the wood pulp fibers are bleached chemical wood pulp fibers. 
     
     
         11 . The method of  claim 9 , wherein the thermoplastic polymer is selected from the group consisting of biopolymers, polylactic acid, cellulose acetate, cellulose propionate, cellulose butyrate, polycarbonates, polyethylene terephthalate, polyolefins, polyethylene, high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, polystyrene, polystyrene copolymers, acrylonitrile-butadiene-styrene copolymer, styrene block copolymers, polyvinyl chloride, and recycled plastics. 
     
     
         12 . The process of  claim 9 , further comprising cooling the water filtered from the pellet, recycling the water to the extrudate. 
     
     
         13 . The method of  claim 12 , wherein the wood pulp fibers are bleached chemical wood pulp fibers. 
     
     
         14 . The method of  claim 12 , wherein the thermoplastic polymer is selected from the group consisting of biopolymers, polylactic acid, cellulose acetate, cellulose propionate, cellulose butyrate, polycarbonates, polyethylene terephthalate, polyolefins, polyethylene, high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, polystyrene, polystyrene copolymers, acrylonitrile-butadiene-styrene copolymer, styrene block copolymers, polyvinyl chloride, and recycled plastics. 
     
     
         15 . The method of  claim 9 , further comprising pumping the extrudate to the die. 
     
     
         16 . The method of  claim 9 , wherein the extrudate comprises 20 to 40 weight % wood pulp fiber and 55 to 75 weight % thermoplastic polymer.