Abstract

In this study, the delimed and bated cattle hide was pre-tanned with 2% TWS tanning agent, after salt-free pickling the pre-tanned leather was combination-tanned using TWLZ tanning agent. The results showed that, with this combined tanning system, the shrinkage temperature of the TWS-TWLZ tanned leather increased with increasing the amount of TWLZ tanning agent. When the amount of TWLZ was 6%, the moisture and heat resistance of the crust leather tended to be balanced, and the shrinkage temperature reached the peak of 84.5°C. Compared with conventional TWLZ tanning, the shrinkage temperature of the combined-tanned leather increased by 12.1°C; the dispersion of TWLZ was much more even in the cross-section of leather, showing an increasing uptake rate as well, thus leading to a flat and fine grain surface, full body, no loose fibres, and higher mechanical strength of the combined-tanned leather. The TWS-TWLZ stepwise combined-tanning system represents a clean chrome-free tanning process.

Details of the products used are restricted for commercial reasons but the detailed manner in which the process results are examined add to the presentation. Some details are given in the appendix.