铬鞣助剂OXD-I的应用工艺优化及高吸收铬鞣机理研究

通过改变OXD-I铬鞣助剂的应用工序、用量、提碱终点的pH值以及铬鞣剂用量等应用条件,对OXD-I的应用工艺进行了优化。进而研究了OXD-I助剂与皮胶原、铬鞣剂间的相互作用以及OXD-I助鞣的革坯的铬结合牢度,探讨了OXD-I的高吸收铬鞣机理。结果表明,OXD-I助剂的优化工艺为:2%的OXD-1在铬鞣前加入,KMC铬鞣剂用量为5%,鞣制终点pH值控制在4.0左右;废液中Cr2O3可降至0.18g/L,铬吸收率达到97.0%。革坯染色性能优良,丰满性良好,其抗张强度、撕裂强度均能明显高于普通铬鞣革;OXD-I的高吸收机理为:OXD-I助剂先与胶原上的活性基团发生化学反应,将羧基、羟基以及胺基等基团引入胶原纤维上。在鞣制过程中,助剂上羧基与胶原侧链羧基等共同与三价铬配位,形成了交联配位结合、单点配位结合以及环状螯合等不可逆结合,这些协同作用使OXD-I助剂具有很强的助铬吸收能力。

Technics Optimization and High Exhaustion Chrome Tanning Mechanism for OXD-I Auxiliary

The optimum technics of the auxiliaries is investigated by changing processes and dosages of OXD-I,pH value of basifying,as well as dosages of chrome tanning agents.Simultaneously,the high exhaustion chrome tanning mechanism of OXD-I auxiliary is studied by means of investigating the interaction among the auxiliary,collagen and chrome tanning agent as well as studying the connecting fastness between the chrome salt and collagen.The results indicat that the optimum application technics of this auxiliary was: 2% OXD-I chrome tanning auxiliary combined with 5% KMC chrome tanning agent in the leather tanning,the final pH of the chrome tanning was about 4.0.The content of Cr_2O_3 in the wastewater was decreased to 0.18g/l and chromium absorptivity was 97.0%.The finished leathers had good fullness and dyeing performance as well as higher tensile and tear strength which were obviously better than that of traditional chrome leather.The high exhaustion chrome tanning mechanism of OXD-I auxiliary was suggested to be: OXD-I formed firm covalent bond with collagen,and then the carboxyl groups,hydroxyl groups and amino groups of OXD-I were introduced to the backbone of collagen.In the tanning process,the carboxyl groups 0f OXD-1 cooperating with sidechain of collagen coordinated with chrome,and forming several reversible fixations of chrome,such as cross-linking,single-point reaction,and chelation,which were considered to contribute to the high chrome absorption of leather.