Studies On The Artificial Dyeing Of Popular And Fraxinus Mandshurica Veneer

This paper took the Popular veneer and the Fraxinus mandshurica veneer as the testing pieces. The optimum process conditions and the formulations for dyeing are obtained through the study.Firstly, the experiment is to use the UV light irradiation apparatus irradiating the direct dye, acid dye, reactive dyeing Popular veneer for about 155 hours. The best dye in lightfastness and the dye species used for veneer simulating rare trees were obtained, and the effect of dye concentration, temperature, bath ratio, time on the ability lightfastness of dyeing veneers was discussed. Secondly, the veneers of Popular and Fraxinus mandshurica were dyed by the reactive dye. The effect of dye concentration, temperature, bath ratio, time on dye-uptake were analysed, and also the dyeing mechanism. The best process parameters of dye-uptake on the veneer of Popular and Fraxinus mandshurica were confirmed. Thirdly, it is the first time that the pretreatment of chitosan-immersion was applied to the wood dyeing technology. The effect of pretreatment of chitosan-immersion on dye-uptake was determined. Fourthly, the microstructure of Fraxinus mandshurica was measured by the scanning electron microscope and the image analysis software of wood, and then the microstructure factors that influence the dyeing effect were confirmed after analyses of the correlation analysis between the microstructure of Fraxinus mandshurica and the dyeing effect. Fifthly, the computer color matching was applied to the veneer simulating rare trees. The formulations for dyes of Popular veneer simulating four natural rare trees, Red Ebony,Beech,Tectona grandis,Dalbergia hupeana were obtained, and also the Fraxinus mandshurica veneer simulating two r natural rare trees, Thitsi melanochyla, Rengas gluta.The research results showed that lightfastness of reactive dye is the best and the lightfastness of the direct dye is the worst when the different dyed veneers were under the irradiation of UV light irradiation apparatus. The reactive dye chemically reacts with wood to form the tight covalent bond in the dyeing process; while the bond between the acid dye, direct dye and wood is the physical adsorption between molecules. The best process parameters of dye-uptake on the Popular veneer are followed as:2% dye concentration,60℃,120min, bath ratio 1:20,30 g/L concentration of NaCl,10 g/L Soda Fraxinus mandshurica concentration. It provides the theory and practical guide for Popular veneer simulating rare trees. The pretreatment of chitosan-immersion can enhance the dye-uptake. The concentration of chitosan, the time of pretreatment, temperature, bath ratio had evident effects on the dye-uptake. The best process parameters of dye-uptake on the Fraxinus mandshurica veneer are followed as:1% dye concentration,95℃,240min,40 g/L concentration of NaCl,10 g/L Soda Fraxinus mandshurica concentration, bath ratio 1:10. After analyses of the correlation between Popular microstructure and dyeing effect, it concludes that Tangential lumen diameter, density, proportion of vessel and the ratio of wood fiber lumen diameter are the factors that affect the dyeing effect. It provides the theoretical guidance for choice and cultivation of dyed wood.The final formulations for dyes of Popular and Fraxinus mandshurica veneers simulating rare trees were confirmed with computer matching and actual operation. The formulation for dyes of Popular simulating Red Ebony is followed as:0.5539% reactive brilliant red X-3B,0.8625% reactive yellow X-R,0.2052% reactive blue X-R. The formula for dyes of Popular simulating Beech is followed as:0.0315% reactive brilliant red X-3B,0.2775%reactive yellow X-R,0.0125% reactive blue X-R. The formulat for dyes of Popular simulating Tectona grandis is followed as: 3.1989% reactive brilliant red X-3B,7.0572% reactive yellow X-R,1.8220% reactive blue X-R. The formula for dyes of Popular simulating Dalbergia hupeana is followed as:0.2720% reactive brilliant red X-3B,1.6444% reactive yellow X-R,0.0869% reactive blue X-R.; The formula for dyes of Fraxinus mandshurica simulating Thitsi melanochyla is followed as:0.3919% reactive brilliant red X-3B,0.3120% reactive yellow X-R,0.0664% reactive blue X-R. The formula for dyes of Fraxinus mandshurica simulating Rengas gluta is followed as:0.3071% reactive brilliant red X-3B,0.2711% reactive yellow X-R,0.0480% reactive blue X-R.The research results have important realism meaning to provide the theory and practical guide for Popular and Fraxinus mandshurica veneer simulating rare trees.