The efficacy of Mimosa tannin, chemically modified tannin, and tannin-copper complexes as wood preservatives was evaluated.
Mimosa Tannin (MT), mimosa tannin treated with trichloroacetic acid (TMT), resorcinolated mimosa tannin (RMT) and catecholated mimosa tannin (CMT) were prepared as tannins. The treated specimens showed satisfactory decay resistance in a basidiomycete laboratory test using Formitopsis palustris according to the Japanese Industrial Standard (JIS) K 1571 : 1998. When wood powder was treated with these agents, mycelial growth and generated protein decreased to some extent. The preservative effects of the chemically modified tannins (RMT and CMT) or compound agents composed of the tannins and ammonia-copper were considered to be due to inhibition of the activities of xylanase, mannase and CMCase. In the culture medium where treated wood powder was put in with these agents, drop of pH by oxalic acid, which F. palustris produces, is not generated.

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