Abstract

Chrome-tanned leathers have good comprehensive properties but, tannery effluents with high salinity, chromium and leather scraps containing chromium have a serious environmental impact. Non-chrome tannage is one of tannages that can reduce the pollution. Current non-chrome tanned leather canʼt, unfortunately meet the needs of the leather market regarding shrinkage temperature, softness, handle and other properties. In this study, a novel combination tannage was developed. The novel non-chrome tanning agent SL was directly employed to tan bated bovine hide producing wetwhite. The shaved wet-white was further tanned by Tara, Sellatan RL and Lutan BN and was then fatliquored. It was found that the optimal consumption of the tannins – novel non-chrome tanning agent SL, Tara, Sellatan RL and Lutan BN was 5wt% for SL (based on 150% times of the weight of bated hide pelt) and 6wt% for each of the other three tannins (based on the weight of the shaved wetwhite). The shrinkage temperature of the finished leather can reach over 100°C and the leather has good softness, handle and mechanical properties. Compared with the traditional chrome tanning the conventional pickling process was eliminated, thus the process was shortened and the pollution by sodium chloride was reduced. The quality of the non-chrome leather approaches that of chrometanned leather. The non-chrome leathers of pilot production have been approved and accepted by the leather market.