Abstract

A glycine-modified calcium lignosulfonate (GCL) was prepared through the Mannich reaction, and a novel chrome-free tannage method based on aluminum (Al) and GCL was developed. The results indicate that GCL has strong filling effect and can improve hydrothermal stability (Ts) and fullness of leather in Al-GCL combination tanning. The leather tanned with 2% Al (Al2O3) and 10% GCL has a Ts of 83.5°C with a 90.6% increase in thickness. Compared with plain lignosulfonate, the performance of GCL is much better in the combination tannage with Al due to the introduction of glycine in lignosulfonate molecule. In addition to hydrogen bond and hydrophobic interactions between GCL and collagen, the coordinate reaction between carboxyl of glycine and Al should be the main mechanism for achieving the efficiency of Al-GCL combination tanning. GCL is seen as a possible replacement for vegetable tannins.