Abstract
Effectiveness of surface coating with Kakishibu (tannin of Japanese persimmon, Diospyros kaki Thunb.) and the improved ones against decay fungi was tested.
The test was carried out as described in JIS K 1571: 2004. Wood specimens used were sugi (Cryptomeria japonica D. Don) sapwood. Mass losses of specimens coated with Kakishibu, not leached and subjected by Fomitopsis palustris - FFPRI 0507 and Trametes versicolor - FFPRI 1030, were more than 14% and 8%, respectively. Hyphae of F. palustris entered to the inside of the specimens from cracks of the film of tannin, and hyphae of T. versicolor passed through the film.
However, the both mass losses became less than 4% when the Kakishibu adding glutaraldehyde and copper sulfate was used for surface coating at two times, though leaching treatment was carried out. By these results, it was thought that aldehyde and copper improved water- and fungal resistance of Kakishibu, respectively.
