Fiber cement composite material using biocide treated durable cellulose fibers

Abstract

A fiber cement composite material providing improved rot resistance and durability, the composite material incorporating biocide treated fibrous pulps to resist microorganism attacks. The biocide treated fibers have biocides attached to inner and outer surfaces of individualized fibers to protect the fibers from fungi, bacteria, mold and algae attacks. The biocides selected have strong affinity to cellulose and do not interfere with cement hydration reactions. This invention also discloses the formulation, the method of manufacturing and the final fiber cement products using the biocide treated fibers.

1 . A composite building material, comprising: 
 a cementitious matrix; and    cellulose fibers incorporated into the cementitious matrix, wherein the cellulose fibers are at least partially treated with a biocide chemical that inhibits microorganism growth inside the fibers.    
     
     
         2 . The composite building material of  claim 1 , wherein the biocide chemical is attached to inner and outer surfaces of the fibers.  
     
     
         3 . The composite building material of  claim 1 , wherein the chemical is selected from the group consisting of fungicides, algaecides, mold and termite preservatives, and mixtures thereof.  
     
     
         4 . The composite building material of  claim 1 , wherein the chemical comprises inorganic compounds.  
     
     
         5 . The composite building material of  claim 4 , wherein the inorganic compounds are selected from the group consisting of sodium, potassium, calcium, zinc, copper, and barium salts of carbonate, silicate, sulfate, halide, and borate; zinc carboxylates; boric acids; sodium dichromate; copper oxene; copper chrome arsenate (CCA); chromated copper borate (CBC); ammoniacal copper arsenate (ACA); ammoniacal copper zinc arsenate (ACZA); copper chromium fluoride (CFK); copper chromium fluoroborate (CCFB); and copper chromium phosphorous (CCP), and combinations thereof.  
     
     
         6 . The composite building material of  claim 1 , wherein the chemical comprises organic compounds.  
     
     
         7 . The composite building material of  claim 6 , wherein the organic compounds are selected from the group consisting of propiconazole, tebuconazole, organochloride, quaternary ammonium compounds (AAC), tri-n-butyltin oxide (TBTO), tri-n-butyltin naphthenate (TBTN), didecyldimethylammonium bromide (DDAB), didecyldimethylammonium chloride (DDAC), and mixtures thereof.  
     
     
         8 . The composite building material of  claim 1 , wherein the chemical comprises about 0.01% to 20% of the dry weight of the treated cellulose fibers.  
     
     
         9 . The composite building material of  claim 1 , wherein the cellulose fibers are made from cellulose pulps of a lignocellulosic material by a pulping process.  
     
     
         10 . The composite building material of  claim 9 , wherein the fiber lengths are between about 0.2 and 7 mm.  
     
     
         11 . The composite building material of  claim 10 , wherein the fiber lengths are between about 0.6 and 4 mm.  
     
     
         12 . The composite building material of  claim 1 , wherein the treated fibers comprise about 0.5%-20% by weight of the matrix.  
     
     
         13 . The composite building material of  claim 1 , further comprising untreated cellulose fibers.  
     
     
         14 . The composite building material of  claim 1 , further comprising natural inorganic and synthetic fibers.  
     
     
         15 . The composite building material of  claim 1 , wherein the cementitious matrix and the individualized cellulose fibers are autoclaved.  
     
     
         16 . The composite building material of  claim 15 , further comprising an aggregate.  
     
     
         17 . The composite building material of  claim 16 , wherein the aggregate is ground silica.  
     
     
         18 . The composite building material of  claim 1 , comprising about 10-80% cement by weight.