Abstract

Lime fleshings were hydrolysed with a proteolytic enzyme and further broken down to the amino acid level (as previously described) before preparing the corresponding aldehyde, which was then used as a cross-linking agent in tanning, in the study the product is labelled as CA. In this study, the cross-linking agent prepared above was used as an exhaust aid in chrome tanning, rechroming and vegetable tanning to give improved tannin exhaustion. Using 2% cross-linking agent in chrome tanning improved chrome exhaustion from 67 ± 1.0% to 92 ± 1.5%; similarly, in vegetable tanning, the exhaustion of wattle extract increased from 86% to 93%. Effluent value reductions were found together with improvements in shrinkage temperature, dyeing properties and physical strength. The chrome tanned crust leather and rechromed crust leathers were softer and tighter than control leathers.