ART和其它多种复鞣剂对铬鞣革的漂白和耐光机理及其表征的研究

Study on the mechanism of bleaching and lightfast behaviour and characterization of ART and other retanning agents for the chrome leather

对采用 ART丙烯酸树脂复鞣剂及其它复鞣剂复鞣的铬鞣革的紫外及可光光谱的特性、白度值和耐光性进行了试验、分析。对白度的表征方法做了探讨 ,建立定量公式的结果与常规白度相吻合。同时提出 ,从皮革白度的角度来讲 ,所有鞣剂可分为四种 ,即有增白效果的、有漂白效果的、对白度无影响的和对白度有不良影响的。本文还从配位场理论的角度研究了 ART及其它复鞣剂对皮革的漂白机理。 ART复鞣剂分子结构中的羧基一方面与铬配位 ,降低了配位体的稳定化能 L FSE( Dq) ,另一方面其反式配合物的空间构型 ,降低了 Dq值 ,使光谱中的 Q1谱带向短波方向移动 ,从而显著增加了白度。研究结果证明 ,ART复鞣剂和 STW复鞣剂具有优良的漂白、增白效果。

By means of the analysis of the visible and UV spectroscopy, white degree and lightfastness of chrome leather specimens retanned by ART acrylic resin and others, this paper, first, explored characterising method of white degree, establishing its quantitative formula consistent with a common view and confirming the reliability of employed equipment. Meanwhile, from a point of view of white degree value, all tanning agents could be classified as follows: 1. whitening tannage;2.bleaching tannage;3.non-detrimental tannage and 4. detrimental tannage. Second, using Ligand Field Theory accounted for the bleaching mechanism of ART and other tanning agent's. It was verified that ART carboxyl groups, on the one hand, coordinated with chromium of chrome leather to make LFSE(D q) of the coordinated compound reduce, on the other hand, its nitrogen-atom-containing ligand combined with the chromium of chrome leather to have Q 1 band shift to short wavelength, upon which the value of white degree increased measurably. Third, thanks to the investigations of lightfastness, it was found that ART and STW were perfect whitening, bleaching and lightfast tanning agents.