Preservation of wood, compositions and methods thereof

Abstract

The disclosure relates to compositions for wood preservation and methods of applying compositions for wood preservation. The compositions comprise nonionic surfactant mixtures and prepolymer. Compositions of nonionic surfactant mixtures and prepolymers can be used advantageously in methods to preserve wood by impregnation of the wood with preservatives at ambient atmospheric pressures.

We claim: 
     
         1 . A method of preserving wood comprising:
 (a) contacting a wood with a solution of a pre-polymer and nonionic surfactant; and   (b) curing the wood that has been contacted with the solution of prepolymer and nonionic surfactant; wherein   the method is conducted from about ambient atmospheric pressure to about 15 psig;   the solution of prepolymer and nonionic surfactant comprises from about 2 wt % to about 20 wt % of the total weight of solution of the prepolymer and nonionic surfactant;   the prepolymer is water soluble and capable of impregnating the wood, and   the curing step comprises heating the wood at temperatures above 25° C.   
     
     
         2 . The method of  claim 1 , wherein the curing step comprises heating the wood at temperatures above 35° C. 
     
     
         3 . The method of  claim 1 , wherein the solution of pre-polymer comprises an aqueous solution of phenol-formaldehyde prepolymer; wherein
 the weight average molecular weight (MW w ) of the phenol-formaldehyde prepolymer is in the range of from about 125 to about 400.   
     
     
         4 . The method of  claim 1 , wherein the nonionic surfactant comprises alkylpolyglycosides and ethoxylated alcohols. 
     
     
         5 . The method of  claim 1 , wherein the pre-polymer is a water soluble pre-polymer in aqueous base. 
     
     
         6 . The method of  claim 1 , wherein the method is conducted from about atmospheric pressure to about 10 psig. 
     
     
         7 . The method of  claim 1 , wherein the method is conducted from about atmospheric pressure to about 5 psig. 
     
     
         8 . The method of  claim 1 , wherein the method is conducted from about atmospheric pressure to about 1 psig. 
     
     
         9 . The method of  claim 1 , wherein the solution of pre-polymer and nonionic surfactant comprises in the range from 5 wt % to 10 wt % of prepolymer. 
     
     
         10 . The method of  claim 1 , wherein the solution of pre-polymer and nonionic surfactant comprises in the range from 6 wt % to 8 wt % of prepolymer. 
     
     
         11 . The method of  claim 1 , wherein the wood comprises a utility pole. 
     
     
         12 . The method of  claim 11 , wherein the solution of pre-polymer and nonionic surfactant is applied only to one end or both ends of the utility pole. 
     
     
         13 . The method of  claim 1 , wherein the solution of pre-polymer and nonionic surfactant is applied by at least partially submerging the wood in the solution. 
     
     
         14 . The method of  claim 1 , wherein contacting the wood with the solution of pre-polymer and nonionic surfactant comprises first applying the solution to the wood and then applying a pressure of up to 24 psig to the wood and applied solution. 
     
     
         15 . The method of  claim 1 , wherein the solution of pre-polymer and nonionic surfactant is applied by at least partially submerging the wood in the solution. 
     
     
         16 . The method of  claim 1 , wherein the contacting the wood with the solution of pre-polymer and nonionic surfactant comprises first applying the solution to the wood and then applying a pressure of up to 24 psig to the wood and applied solution. 
     
     
         17 . The method of  claim 1 , wherein the curing comprises a first curing step and a second curing step, wherein during the first curing step the wood is heated to a temperature above 25° C., and during the second curing step the wood is maintained at ambient temperature. 
     
     
         18 . The method of  claim 1 , wherein the curing has a duration of multiple days. 
     
     
         19 . The method of  claim 1 , wherein during the curing some of the prepolymer crosslinks with reaction sites in or on the wood. 
     
     
         20 . The method of  claim 1 , wherein the preserved wood has a modulus of elasticity that is about 35 to about 40% higher than a modulus of elasticity of the wood before preserving.