Study On Chemicl Coloration Of Eucalypt Veneer

The plantation eucalypt wood is characterized by numerous knots, dull and uneven color. Chemical coloration method was used in this study to improve the visual effect of eucalypt veneer surface, in order to enhance utilization value of eucalypt plantation. Meanwhile, the technology of recycling use of treating solution was tested to reduce waste water, to reduce production costs, and to reduce environment burden. In order to know whether or not the chemical coloration treatment would have negative effects on processing properties of eucalypt veneer, LVL was manufactured with treated veneers, and LVL mechanical property determination was carried out. The main conclusions were as follows.1. Potassium dichromate was screened out as the most suitable chemical formulation, the treated veneer would be evenly brown-colored from surface to inside part, with a color effect similar to teak wood, and the problem of color difference caused by the numerous knots on the surface of eucalypt veneer would be overcome perfectly.2. To get the optimal parameters for coloration treatment of eucalypt veneer, factors with influence on treatment effect were analyzed. The optimal parameters were as follows: concentration of chemical solution0.8%, solution temperature70℃, bath ratio15:1and bath time10h.3. Four times of recycling use of treating solution was achieved through adding potassium dichromate of consumed amount to the solution after each time, and there was no difference between coloration effects of different times. This illustrated that recycling use of treating solution would be possible. The treating cost of chemicals was estimated as350.25yuan/m3based on four times of recycling use of treating solution.4. LVL products was successfully manufactured with treated veneers under optimal processing conditions selected in this study. MOE and MOR of the LVL products reached national standards for the1st class products and the180E level. This illustrated that the chemical coloration treatment didn’t show any negative influence on processing properties to eucalypt veneer.