Research On The Technology Of Improving The Lightfastness Of Dyed Veneer Of Birch

Wood dyeing is a process of coloring wood with dyestuffs based on the natural grain of wood. One of the most important standard of dyed wood is the ability of lightfastness. Improving the lightfastness of dyed wood has great practical significance in many aspects, such as planted woods' development and processing and the progressing on the technology of wood decorative material, and so on.This paper discusses how to improve the lightfastness of dyed wood through the three parts of research which involve the lightfastness of five kinds of dyestuff, the process of wood dyeing and the application of light stabilizers. Results as follows are obtained.This experiment takes birch veneer as material and acid, cation, direct light, disperse and reactive dyestuffs as dyestuff. The lightfastness of reactive and direct light dyestuffs are the best in these five kinds of dyestuffs, which acid dyestuff is secondary to, and cation and disperse dyestuffs are the worst of the five kinds. The AE values of veneer dyed with reactive yellow FN-2R, red FN-3G and blue FN-R are 14.03, 20.24, 21.78. The AE values of veneer dyed with direct yellowRS, red 4BL and blue B2RL are 10.85, 12.52,21.83.In the orthogonal experiment, temperature's effect on the lightfastness of dyed veneer is significant, value of pH and time's effect on the lightfastness of dyed veneer is not significant. Veneer with higher lightfastness can be dyed under the condition of pH 3.50, time 5h and tempreture 95℃. Value of pH and time's effect on the value of L of dyed veneer is significant, temperature's effect on the value of L of dyed veneer is significant. And the three factors' effect on value of a~*, b~* are not significant.The three different ways to apply light stabilizers all have some effect to improve the lightfastness of dyed veneers. But the method of painting dyed veneer with PU including the light stabilizers is much better than the other two. The AE value of acid blue BGA veneer after 100-hour radiation, which hasbeen painted with the mixture of PU and UV-326, decreases 23-27. But the one of acid blue BGA veneer after 100-hour radiation, which has been treated with the former methods, decreases only 9.33.