Use of Sub-Micron Copper Salt Particles in Wood Preservation

Abstract

A method for preserving wood by injecting into the wood a slurry having: particles of a sparingly soluble copper salt, copper hydroxide, or both, wherein the weight average diameter d50 of the particles in the slurry is between 0.1 microns and 0.7 microns and the d98 of the particles in the slurry is less than about 1 micron; a dispersant; and water. The dispersant is anionic or a mix of anionic and non-ionic. Advantageously, less than 20% by weight of the particles have a diameter less than 20 nanometers. Useful copper salts include basic copper carbonate, tri-basic copper sulfate, copper oxychloride, basic copper nitrate, basic copper borate, copper borate, basic copper phosphate, or copper silicate. The slurry most preferably includes copper hydroxide particles. The slurry further advantageously includes at least one organic biocide, wherein at least a portion of the organic biocide is coated on the particles.

Dependencies are inferred from the claim text.