Study On The Cationic Coupling Agent For Leather Dyeing

This paper relates to zircoaluminate coupling agents forleather dyeing which were prepared with aluminum chlorhydroxide andzirconium oxyhalide as the main materials and glutamic acid anddodecyl betaine as organo functional group. These zircoaluminatecoupling agents were water soluble and have cationic group, while usein leather dyeing process, they can play a "molecule bridge" role tocombine anion dyestuff and leather fibers which increases the bindingforce between them. So these zircoaluminate coupling agents can havethe color fixed function for leather dyeing process. Furthermore, thealuminum and zirconium ion complex the chromium ion in the leather,which avoid the dissociation of the chromium ion, accordinglydecreases the pollution of the dyeing water.The results indicate:(1) These zircoaluminate coupling agents have goodmechanical stability and resistance to cold and hot, it will haveoptimum effect while using at the pH less than 4.0(2) The differential thermal analysis and the determination ofmelting point indicate these zircoaluminate coupling agents are stableunder 300℃.(3) When determining the absorbance curves of the dyestuffwhich adding the zircoaluminate coupling agent with spectrophotometer,the highest absorbance wavelength will move to the direction of longwave. The strength of the highest absorbance wavelength increaseswhen increasing the dosage of zircoaluminate coupling agent. That saidthese zircoaluminate coupling agents indeed have deepening andbrightening function for dyestuffs.(4) When using these zircoaluminate coupling agents as dyeauxiliary in the leather dyeing process, the absorbance of axunge, thedye uptake, the color fastness can be improved and the K/S value canalso be increased.(5) It will have the best deepening and color fixed effect whenadding the zircoaluminate coupling agents after fixing color by formicacid in the dyeing process;the optimum dosage is 1%.All the research above can show: these cationiczircoaluminate coupling agents endow the good function of deepening,brightening, and color fixed in the leather dyeing process. Besides, thealuminum and zirconium ion can have reiteration tanning function forthe leather and decrease the cost of the product. Furthermore, thesezircoaluminate coupling agents have the advantage of low cost andsimple synthesis, they will have good application prospect for leatherdyeing process.