低盐和低碱活性红染料在柞木单板染色中的应用

  目的  明确低盐和低碱活性染料应用于单板染色的适用性，可降低染液废液污染水平和生产成本。  方法  选择新型低盐活性大红(SNE)染料和低碱活性红(LA)染料对渗透性较差的柞木Xylosma japonicum单板进行染色，以应用较广的活性红(M-3BE)染料作为对照，测试3种染料染色柞木单板的直接性、反应性、固色率和染色效果，利用傅里叶红外光谱(FTIR)、热重分析仪(TG)和扫描电镜(SEM)分析其官能团、组分和细观结构的变化。  结果  与M-3BE染料相比，SNE染料硫酸钠用量降至1/2和LA染料碳酸钠用量降至1/8时，SNE染料固色率提高了15.33%、色差降低了1.35%，LA染料固色率降低了3.37%、色差提高了2.03%。染色处理后，木材表面羟基含量减少，其中低盐染料染色柞木单板羟基含量最低，除出现较弱的硫酸盐S=O吸收峰外，无新吸收峰产生。3种活性染料与木材的结合机理和产生的官能团结构相似，但因染料母体结构差异较大，导致热分解曲线略有不同。染料分子可从木材表面扩散到木材内部，扩散程度从大到小依次为SNE、M-3BE、LA。  结论  SNE染料具有较高的上染率，LA染料具有优异的颜色提升性，可用来染色木材单板，从而降低电解质盐和碱的排放。图3表3参28

Application of low-alkali and low-salt reactive red dyes in Xylosma japonicum veneer dyeing

  Objective  This study is to analyze the applicability of low-alkali and low-salt reactive red dyes in veneer dyeing, with the purpose of reducing the pollution of dyeing wastewater and the cost of production.  Method  A new low-salt reactive red dye(SNE) and low-alkali reactive red dye(LA) were selected to dye Xylosma japonicum veneers with poor permeability. The widely used reactive red dye (M-3BE) was used as control. The substantivity, reactivity, fixation rate and dyeing effects were tested. Fourier transform infrared spectroscopy(FTIR), thermal gravimetric(TG) analyzer and scanning electron microscopy(SEM) were used to analyze the changes of functional groups, wood components and microstructure of specimens.  Result  Compared with M-3BE, when the dosages of Na₂SO₄ and Na₂CO₃ were reduced to 1/2 and 1/8 respectively, the fixation rate of SNE increased by 15.33% and color difference decreased by 1.35%, while the fixation rate of LA decreased by 3.37% and color difference increased by 2.03%. After dyeing, the hydroxyl content on the wood surface decreased, and the lowest hydroxyl content was detected on the X. japonicum wood surface dyed with SNE dyes. No new absorption peak was observed on the dyed X. japonicum veneers except weak sulfate S=O absorption peak. The mechanism and the functional group structure between three reactive dyes and wood were similar. The thermal decomposition curves were slightly different due to differences in the parent structures of the three reactive dyes. All dye molecules could diffuse to the wood interior from the wood surface, and the order of diffusion degree from large to small was SNE, M-3BE, and LA.  Conclusion  SNE has high dye uptake and LA has excellent color effect, which can greatly reduce the discharge of electrolyte salt and alkali. Ch, 3 fig. 3 tab. 28 ref.]