Abstract

The huge amount of fleshings from tanneries around the world creates a negative environmental impact, in addition to disposal costs; these wastes are not well used. This paper presents some innovative processes for reclaiming the fats carried by a large variety of flesh hides or skin wastes, along with the fatty matter separation and modification to obtain a surface active material intended to be used as leather softening agents.

The fat was extracted with hot water at a fixed temperature (85 ± 5°C, solid: water 1:1 w/v and 2 hours stirring time). The fat rich phase was then separated and purified with n-hexane (fats: n-hexane 1:8 w/v, ambient temperature and one hour stirring time). The fat was cooled to 12°C and filtered under pressure to isolate the unsaturated oleic fraction and exclude the stearic fraction. The chemical evaluation of oleic fraction indicated that it was suitable for the production of leather softening (fatliquoring) agent. The product was treated with sodium bisulfite (1.5mol/kg based on weigh of fat, 85°C, 2 hours stirring and continuous air flow). A good quality fatliquoring agent was produced. Application of the fatliquor emulsion on wet-blue leather showed enhanced mechanical properties, tensile strength, elongation and improved appearance. Thereby the waste was transformed into a valuable resource.