Wood bulking involves swelling wood to its maximum dimension and retaining it at that dimension by depositing a bulking agent in the cell walls and cavities. It is economically prohibitive and may have a negative effect on wood strength properties. Physically restricting water access in wood by impregnating it with hydrophobic agents limits boron mobility without interfering with its bioactive nature. Lower water absorption and a reduction of void spaces can contribute to the immobility of boron. Use of water dilutable resins in a water miscible solvent to which a wood treating chemical is added deposits preservative and resin into the cell wall where it is converted to an insoluble form. The components must be comprised of molecules capable of entering voids in the cell wall and be converted to a more water insoluble form at ambient conditions either by itself
or aided by other chemicals that act as catalysts (Ramesh and Dodwell, 1981; Mohareb et al., 2002; Hutter et al.,
2004). Impregnating wood with an aqueous liquid dispersion or emulsion which contains a borate and rosin or rosin derivative simultaneously incorporates borate into wood and renders it hydrophobic. Suitable rosins include tall oil rosin, gum rosin, or wood rosin.