In this study, Fraxinus mandshurica veneer was dyed with reactive brilliant red X-3B, black KN-B and blue K-3R dyes. The dye concentration, bath ratio and dyeing time were selected for an orthogonal experiment. Analysis of variance showed that the dye concentration had the greatest effect on the dye uptake of F. mandshurica veneer. In the independent experiments, dye uptake increased at first and then decreased with increasing dye concentration; the chromatic aberration increased with the dye concentration and then remained steady. The infrared spectra were used to examine the dyeing behaviors before and after dyeing and the binding form between reactive dyes and F. mandshurica veneer was analyzed. Based on the optimization of process parameters, the optimal dyeing condition was considered to be 75 °C, the dye concentration to be 0.5⁻1.0%, the dyeing time to be 60 min and the bath ratio to be 20:1. The dye uptakes of reactive brilliant red X-3B, black KN-B and blue K-3R dyes were 75.0⁻75.4%, 50.0⁻64.6% and 32.0⁻66.0%, respectively. The chromatic aberration of F. mandshurica veneer dyed with reactive brilliant red X-3B, black KN-B and blue K-3R dyes was 53.0⁻59.0, which was a significant increase. After dyeing, the hardness and impact strength of the waterborne coating on the dyed F. mandshurica increased but adhesion was reduced. The coating films produced a matte glossiness.
Keywords: Fraxinus mandshurica veneer; reactive dyes; waterborne coatings.