Synergic effect of bovine hair hydrolysate and sulfited lignins on leather retanning

The aim of this work was the study of bovine hair hydrolysate and sulfited lignins effect in leather retanning process. Bovine hair from hair-saving process was thermally digested in alkaline conditions and after pH adjustment and concentration, was tested as retanning agent. Physical-mechanical tests were applied to evaluate the tear strength and lastometer test (in order to evaluate the grain cracking), and leather behavior regarding softness, grain firmness, and color. The experiments showed that hair hydrolysate, sulfited lignins and its mixtures can be used as retanning agents with good results when compared with a dispersing agent and a synthetic tannin. The keratin hydrolysate was also tested as finishing agent against casein and showed that it is not a good alternative.