Abstract

In order to reduce the disadvantages of chrome tannage, chrome-free tannage was developed by many technologists and tanneries. However, because of the structures and charge of the tanning materials in the chrome-free tannage, the absorption rate of the chrome-free leather for anionic dyestuffs, re-tanning agents and fatliquors is lower than that of the chrome-tanned leather. Therefore, in order to improve the absorptivity of the chrome-free leather for these products, an amphoteric polymer auxiliary agent was synthesized with methyl-acrylic acid, sodium methylallyl sulfonate and dimethyl diallyl ammonium chloride (DMDAAC) by free radical copolymerization using ammonium persulfate at 80°C for 3 hours. The molar ratio of methyl-acrylic acid, sodium methylallyl sulfonate and dimethyl diallyl ammonium chloride was confirmed to be 1.0/0.3/ 1.0. The structure of the amphoteric polymer auxiliary agent was characterized by FTIR, 1H-NMR, 13C-NMR. The charge and properties of the solution of the amphoteric polymer auxiliary agent were characterised. Applied results of the amphoteric polymer auxiliary on the absorption of chrome-free leather for dyestuff and fatliquor, show that it has strong auxiliary absorptive capacity and the absorptive rate of dyestuff and fatliquor is more than 96%.