Wood-based composite board and method of manufacture

Abstract

A wood composite board or panel, such as particleboard, fiberboard, oriented strand board or waferboard and a method of producing the same. The composite board or panel comprises a plurality of wood pieces, thermoset resin to bind the wood pieces and a filler having a high thermal conductivity. Examples of such a filler include natural and synthetic graphites, metal, carbon, silicon carbide and other similar compounds and their mixtures.

We claim:  
     
         1 . A wood composite for making board or panel comprising: 
 a plurality of wood pieces having a thermal conductivity;    a thermoset resin capable of binding said wood pieces, the resin having a thermal conductivity; and    a filler having a thermal conductivity greater than the thermal conductivity of the wood pieces and the resin.    
     
     
         2 . The wood composite of  claim 1 , wherein said filler is selected from the group consisting of carbon fiber, metal coated carbon fiber, carbon nanotubes, coke, natural graphite, synthetic graphite, scrap graphite, carbon black, silicon carbide, silicon nitride, boron nitride, metals and mixtures thereof.  
     
     
         3 . The wood composite of  claim 2 , wherein the filler is a natural graphite, a synthetic graphite or combination thereof.  
     
     
         4 . The wood composite of  claim 1 , wherein said thermoset resin is selected from the group consisting of phenolic resin, urea resin, melamine resin, epoxy resin, urethane resin and mixtures thereof.  
     
     
         5 . The wood composite of  claim 1 , wherein said wood pieces are in a form selected from the group consisting of particles, flakes, fibers and mixtures thereof.  
     
     
         6 . The wood composite of  claim 1  further comprising a catalyst capable of reducing hot-press time, wherein said composite is used to produce board or panel by hot-pressing or combination thereof at an elevated temperature and elevated pressure.  
     
     
         7 . The wood composite of  claim 1 , wherein the wood pieces are acetylated.  
     
     
         8 . The wood composite of  claim 1 , wherein said wood pieces are in the form of fibers, said thermoset resin consists essentially of a urethane resin, a phenolic resin or mixtures thereof; and said filler consists essentially of a carbon filler selected from the group consisting of carbon fiber, metal coated carbon fiber, carbon nanotubes, coke, natural graphite, synthetic graphite, scrap graphite, carbon black and mixtures thereof.  
     
     
         9 . The wood composite of  claim 1 , wherein the thermal conductivity of the filler is greater than 0.2 W/mK.  
     
     
         10 . The wood composite of  claim 1 , wherein the wood composite comprises 40-99.5% by weight wood pieces, 0.50-50% by weight thermoset resin and 0.05-50% by weight filler and further comprises 0-5% by weight catalyst.  
     
     
         11 . The wood composite of  claim 1 , wherein said filler is about 5% by weight of said resin.  
     
     
         12 . The wood composite of  claim 1 , wherein the wood composite is particle board, oriented strand board, waferboard or fiberboard.  
     
     
         13 . A method for manufacturing a wood composite board, the method comprising: 
 mixing a thermoset resin having a thermal conductivity and a plurality of wood pieces having a thermal conductivity to form a blend;    adding a filler having a thermal conductivity to said blend to form a mixture, the filler having a thermal conductivity greater than the thermal conductivity of the resin and the wood pieces;    placing said mixture in a shaped container; and    applying an elevated temperature and an elevated pressure to said mixture in said shaped container to form said wood composite board.    
     
     
         14 . The method of  claim 13 , wherein said filler is selected from the group consisting of carbon fiber, metal coated carbon fiber, carbon nanotubes, coke, natural graphite, synthetic graphite, scrap graphite, carbon black, silicon carbide, silicon nitride, boron nitride, metals and mixtures thereof.  
     
     
         15 . The method of  claim 14 , wherein the filler is a natural graphite, synthetic graphite or combination thereof.  
     
     
         16 . The method of  claim 13 , wherein said thermoset resin is selected from the group consisting of phenolic resin, urea resin, melamine resin, epoxy resin, urethane resin and mixtures thereof.  
     
     
         17 . The method of  claim 13 , wherein said wood pieces are in a form selected from the group consisting of particles, flakes, fibers and mixtures thereof.  
     
     
         18 . The method of  claim 13 , further comprising adding a catalyst capable of reducing time of curing said thermoset resin at said elevated temperature and said elevated pressure.  
     
     
         19 . The method of  claim 13 , wherein said wood pieces or said wood composite board are acetylated.  
     
     
         20 . The method of  claim 13 , wherein said wood pieces are in the form of fibers, said thermoset resin consists essentially of a urethane resin, a phenolic resin or mixtures thereof; and said filler consists essentially of a carbon filler selected from the group consisting of carbon fiber, metal coated carbon fiber, carbon nanotubes, coke, natural graphite, synthetic graphite, scrap graphite, carbon black and mixtures thereof.  
     
     
         21 . The method of  claim 13 , wherein said filler is about 5% by weight of said resin.  
     
     
         22 . The method of  claim 13 , wherein the thermal conductivity of the filler is greater than 0.2 W/mK.  
     
     
         23 . The method of  claim 13 , wherein the wood composite board comprises 40-99.5% by weight wood pieces, 0.50-50% by weight thermoset resin and 0.05-50% by weight filler and further comprises 0-5% by weight catalyst.  
     
     
         24 . The method of  claim 13 , wherein the wood composite board is particle board, oriented strand board, waferboard or fiberboard.  
     
     
         25 . A method of reducing press time in the manufacture of a wood composite board, the method comprising: 
 mixing a thermoset resin having a thermal conductivity and a plurality of wood pieces having a thermal conductivity to form a blend;    adding a filler having a thermal conductivity to said blend to form a mixture, the filler having a thermal conductivity greater than the thermal conductivity of the thermoset resin and the wood pieces;    placing said mixture in a shaped container; and    applying an elevated temperature and an elevated pressure to said mixture in said shaped container to form said wood composite board.    
     
     
         26 . The method of  claim 25 , wherein the wood composite board comprises 40-99.5% by weight wood pieces, 0.50-50% by weight thermoset resin and 0.05-50% by weight filler and further comprises 0-5% by weight catalyst.  
     
     
         27 . The method of  claim 26 , wherein the filler is a natural graphite, synthetic graphite or combination thereof.