立木注入法による木材の染色(第 5 報) : 染色材の退色防止について(林学部門)

In the previous papers, we indicated the dyeing wood which was treated by using sap-flow method for effective utilization of lesser-used species. This dyeing wood has been shown to grow comparatively large discoloration in the color. This paper is to make clear the improvement of discoloration. For finding the method of reasonable treatment and the best condition on prevention of discoloration in the dyeing wood, the effects of the several painting, the types of ultraviolet rays-absorbent and its concentration on the prevention of discoloration of the dyeing wood were evaluated. Result obtained are as follow; 1) It was recognized that ΔE of the dyeing wood were lager maximum 3.1 times than it of the untreated wood. From the result of decomposition of the constituent element, The change amount of b-values have influence greatly to the change of values of ΔE. Therefore, improvement of discoloration is necessity to take the minimum value for the change of b-values. 2) Polyurethane resin paint and fluorine resin paint could not prevailed discoloration by coating the surface of the dyeing wood. However, Fluorine resin paint including ultraviolet rays-absorbent was shown more large the prevention of discoloration. 3) The best effect of prevention was appeared difference by the kind of the ultraviolet rays-absorbent. In the case of Pu, it are best condition for the Tinuvin 320. In the case of Fc, it are Tinuvin P. Especially, the later become the the ΔE values of about from 1/5 to 1/10 times. 4) The concentration of the range of 1%-10% for the ultraviolet rays-absorbent were investigated. And its result indicated no difference for the prevention of discoloration. Therefore, the best concentration was interpret to be 1.0 percent.