MOKUZAI HOZON (Wood Protection)

Show abstractHide abstract

Mycelium of the brown rot fungus (Tyromyces palustris) introduced into agar mediums containing various metallic soaps with different acid values and zinc contents were investigated for fungcidal efficacy. Further more, wood samples of Sugi (Cryptomeria japonica) were treated with the various metallic soaps and exposed to the brown rot fungus for months. Its performance regarding fungicidal efficacy, leaching and iron corrosion were investigated.
The results were as follows; 1) In the agar test, naphthenic acids with higher acid values showed effecive inhibition of fungal growth than the lower acid values. The zinc naphthenates of which the acid values of the original naphthenic acids were high, also showed effective inhibition of fungal growth than those prepared from low acid values. For zinc versatate and zinc octylate, the former showed a slightly higher inhibition of fungal growth than the latter. 2) In the wood decay test, the fungicidal efficacy of zinc naphthenates were varied depending on acid value for each naphthenic acid, even though the retention for zinc were the same. The lower acid values in zinc naphthenates showed the highest fungicidal efficacy. It was preferred that the effectiveness of zinc naphthenates against the fungus be determined by its retention as metallic soaps rather than the zinc content. The naphthenates with higher acid values were readily leachable than the lower acid value naphthenates. It was suggested that differences in leachability may affect the efficacy of the metallic soaps. 3) The results for iron corrosion of the metallic soaps were found to be insignificant in practice.

View full abstract

Download PDF (772K)

Register with J-STAGE for free!