Encapsulated wood preservatives
A method of incorporating biocides into wood or a wood product, the method including the steps of synthesizing a plurality of capsules each having an outer shell of polymer and incorporating within each said capsule an additive which includes an organic biocide, and then applying the said capsules to the wood or wood product in a manner whereby the capsules penetrate the wood or wood product.
1. A microencapsulated organic biocidal composition for impregnating a wood or timber product comprising a plurality of microcapsules each comprising a water immiscible solvent surrounded by a polymeric outer shell, the water immiscible solvent containing one or more organic biocides selected from fungicides, insecticides, and a combination thereof, wherein the one or more insecticide or fungicide is selected from the group consisting of an isothiazolone, a benzothiazole, a pyrethroid, a neonicotinoid, a halogenated carbamate, an azole, a chloronitrile, or a combination thereof, and further characterized in that the mean microcapsule diameter is between about 1.5 microns and about 20 microns such that impregnation of a wood or timber product results in retention of a biocidally effective amount of said biocides within the inner ninth core of said product, wherein the composition is diluted in water.
2. The composition according to claim 1 wherein the composition is and applied to the wood or timber product using standard industry vacuum and or pressure treatment methods to force the microcapsules to penetrate into the inner ninth core and resulting in a biocide retention within the inner ninth core exceeding 75% of the estimated average biocide retention.
3. The composition according to claim 1 wherein the mean microcapsule diameter is less than about 9.2 microns.
4. The composition according to claim 1 wherein the one or more insecticide or fungicide is selected from the group consisting of 4,5-dichloro-2-n-octyle-4-isothiazoline-3-one (DCOIT), chlorothalonil, bifenthrin, and a combination thereof.
5. The composition according to claim 1 wherein the microencapsulated organic biocide further comprises one or more additional water soluble biocides and/or other penetrating adjuvants.
6. The composition according to claim 5 wherein the additional water soluble biocides are quaternary ammonium compounds, metal salts or boron salts.
7. The composition according claim 1 wherein the wood or timber product is at least one of solid wood, orientated strand board, particle board, medium density fibrewood, plywood, laminated veneer lumber, and laminated strand lumber.
8. A wood or timber product impregnated with the microencapsulated organic biocidal composition of claim 1 .