铬交联以及对皮革与其它鞣剂 染料和加脂剂进一步结合的影响

本文解释了铬络合物的数量及它们在胶原晶格中的位置与成革稳定性之间的关系.在用碱式铬盐鞣制的皮革中,铬络合物与皮革的结合方式有许多种,其中只有部分铬络合物与皮革结合的坚牢度最大,也正是这部分铬盐直接影响到皮革鞣制后的耐煮沸试验,其余的铬在中和、搭马陈放和干燥后进—步固定。这—部分铬对皮革提供了很大的额外鞣制强度。通过用二羧酸或聚丙烯酸与这部分未固定的铬或固定不牢的铬结合,成革的—部分额外强度便消失了.这就证明了上述结果。而且这种高吸收鞣法鞣制的革较常规鞣法鞣得的革鞣制强度要轻一点.鞣制强度和铬结合量之间的关系在最近一些报道中也有同样结果,铬的那些自由价键可用于进一步固定油脂,疏水添加剂和复鞣剂。如果要得到与常规铬鞣革相同的鞣制强度,用二羧酸或丙烯酸处理后的革必须加入更多的铬盐鞣制。

The Chromium Crosslink and Its Influence on Further Interactions with Other Tanning Agents Dyes and Fatliquors

An explanation is provided for the relationship between the number of chrome complex- es,their location in the collagen lattice and the level of stability achieved.Leather tanned with basified chrome fixes the chrome with different levels of fastness.Only part of the chrome is fixed at the optimal fastness level and only this fart effects the leather boilfastness examined directly after the tannage.Additional chrome is fixed on neutralisation,on aging, on the horse and after drying.This additional chrome provides leather with a great deal of additional tanning strength.It has been observed that by capturing unbound chrome and the less firmly bound chrome by reaction with dicarboxylic acids or by reaction with polyacrylic acids this additional leather strength is lost.This highly exhausted tanned leather is less tanned than conventional tanned leather.This relationship between tanning strength and the attachment of chrome has been observed in all recently reported cases,where the free va- lences of chrome are used for fixation of fat,hydrophobic additives and retans.It is necessary to add more chrome to obtain the same level of tanning fastness as found in conventional tanned leather.