Non-toxic wood preservatives based on boric acid-protein associations

Boric acid, anon-toxic wood preservative, can not provide long term protection to timber due to its high leachability. The principle involved in this study is to fix boric acid by the formation of an association with different kind of proteins. Within the timber, in presence of boric acid, proteins (egg albumin or collagen) are insolubilized to form a solid polymer network capable of partially fixing this biocide. These systems seem to be a good method to drastically reduce the leaching of boric acid from treated timber. Biological tests have shown that timber treated with such protein borates has excellent durability performances, even when leached. Among these non-toxic protein borates, albumin borate can particularly be classified as long-term, wide-spectrum, heavy-duty, ground-contact wood preservative, showing durability performances comparable to those obtained with copper-chromium-arsenic (CCA) salts. (Résumé d'auteur