Wood Marking and Identification

Abstract

Wood markers and processes for durably marking and subsequently identifying both original grain wood products and wood-plastic composite products. The wood marker can be dispersed beneath the surface of the wood, where it is protected from the elements and may endure years of exposure to the elements. The wood marker is compatible with state-of-the-art pressure-treating processes and may subsequently be detected for authentication purposes by known analytical methods.

What is claimed is: 
     
         1 . A composition of matter, comprising:
 a marker composed of a carboxylate of a metal cation in which the metal is selected from the group consisting of non-biocidal metals having an atomic number in the range of 12 to 83 and mixtures thereof, and a carboxylate anion that includes about 6 to about 18 carbon atoms.   
     
     
         2 . The composition of  claim 1 , in which the selected metal is in Period 3, Period 4, or Period 5 of the Periodic Table of the elements. 
     
     
         3 . The composition of  claim 1 , in which the wood is Southern Yellow Pine. 
     
     
         4 . The composition of  claim 1 , in which the marker is dispersed within the wood. 
     
     
         5 . The composition of  claim 1 , in which the marker is selected from the group consisting of a bismuth carboxylate, cobalt carboxylate, lithium carboxylate, manganese carboxylate, zirconium carboxylate, and mixtures thereof. 
     
     
         6 . The composition of  claim 1 , in which the selected metal is a rare earth metal or a mixture of rare earth metals. 
     
     
         7 . The composition of  claim 1 , in which the marker is fluorescent when excited by x-ray radiation. 
     
     
         8 . The composition of  claim 1 , further comprising one or more biocidal metals. 
     
     
         9 . A process for authenticating a wood product, comprising:
 providing a marker fluid dispersion which comprises:
 a disperse marker phase composed of a carboxylate of a metal cation in which the metal is selected from the group consisting of non-biocidal metals selected from the group consisting of non-biocidal metals having an atomic number in the range of 12 to 83 and mixtures thereof, and a carboxylate anion that includes about 6 to about 18 carbon atoms; a hydrocarbonaceous solvent; and a surfactant; and 
 a continuous phase composed a conventional water-based pressure treating fluid suitable for improving the resistance of the wood product against fire, weathering or of water or microbial attack or a continuous phase composed of water; and 
   depositing a detectable amount of the carboxylate in the wood product by exposing the wood product to the marker fluid dispersion at greater than atmospheric pressure; and   identifying the wood product by detecting the presence of the selected metal or the carboxylate in the wood product to authenticate the pressure-treated wood product.   
     
     
         10 . The process of  claim 9 , which includes drawing air from the wood product by establishing a partial vacuum in or near the wood product. 
     
     
         11 . The process of  claim 9 , in which the carboxylate is selected from the group consisting of bismuth carboxylates, cobalt carboxylates, lithium carboxylates, manganese carboxylates, zirconium carboxylates, and mixtures thereof. 
     
     
         12 . The process of  claim 9 , in which the carboxylate is selected from the group consisting of rare earth carboxylates or mixtures of rare earth carboxylates. 
     
     
         13 . The process of  claim 9 , in which the proportion of the carboxylate in the marker phase in the range of about 10 percent to about 80 weight percent. 
     
     
         14 . The process of  claim 9 , in which the surfactant is an alkyl polyethoxylate, an alkyl aryl polyethoxylate, or an alkyl sulfate. 
     
     
         15 . The process of  claim 9 , in which the marker fluid further comprises one or more biocidal metals. 
     
     
         16 . The process of  claim 9 , in which the continuous phase is composed of a conventional water-based pressure treating fluid suitable for improving the resistance of the wood product against fire, weathering or of water or microbial attack. 
     
     
         17 . An additive composition for marking wood in water or a water-based pressure-treating solution, comprising:
 a hydrocarbonaceous solvent;   a bismuth carboxylate dissolved or suspended in the hydrocarbonaceous solvent; and   a surfactant for dispersing the hydrocarbonaceous solvent and the bismuth carboxylate in water or a water-based pressure-treating solution.   
     
     
         18 . The additive composition of  claim 17 , in which the bismuth carboxylate includes in the range of about 6 to about 24 moles of carbon per mole of bismuth. 
     
     
         19 . The additive composition of  claim 17 , in which the surfactant is an alkyl polyethoxylate or an alkyl aryl polyethoxylate. 
     
     
         20 . The additive composition of  claim 17 , in which the hydrocarbonaceous solvent is a petroleum distillate or a biodiesel that is dispersible within water or within a water-based pressure treating fluid suitable for preserving the wood product against microbial attack.