Recent Patents and Developments in Biocidal Wood Protection Systems for Exterior Applications
Tor P. Schultz, Darrel D. Nicholas and Craig R. McIntyre
Affiliation: Forest Products Laboratory, Box 9820, Mississippi State University, MS 39762-9820, USA.
Keywords: Agrochemicals, biodeterioration, dimensional stability, organic biocides, waterborne formulations, weathering, wood preservation
Wood products used in outdoor applications are treated with biocides to prevent biodegradation by many different fungi and insects. Environmental and disposal concerns have resulted in a rapid and dramatic worldwide shift from the older first-generation preservatives to copper-based systems for residential applications, where the copper(II) is complexed with an organic amine. In the last year the alkaline amine formulation has been partially replaced by microdispersed copper systems that offer several advantages. The current trend in wood preservation is directed towards combining two or more organic biocides in a waterborne formulation employing relatively benign and expensive agrochemicals, with non-biocidal additives sometimes added for increased efficacy and/or other benefits. This review discusses the patents and developments in the past 10 years in biocidal waterborne or solventborne wood protection systems for pressure-treating solid or composite wood products in exterior above-ground or ground-contact applications. Only totally organic systems and related recent developments are discussed, with the exception of microdispersions to formulate both metallic and organic systems.
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