The physico-chemical principles of water-based degreasing of animal skins

Degreasing of animal skins is an important step in leather making. A huge quantity of surfactants is used for this process, which leads inevitably to environmental problems. The development of eco-friendly degreasing agents and processes is therefore desirable. For a better understanding of this process, the fundamental physico-chemical principles must be investigated. Only after such knowledge of the principles has been obtained is the development of a novel class of eco-friendly degreasing agents feasible. At present, the fundamentals are not well understood. In this paper we present our latest research results on the physico-chemical principles of water-based degreasing. In cooperation with the University of Cologne, we were able to determine that degreasing takes place in two distinct steps. The first step, under the proper conditions, is the formation of a nanophase for solubilizing the grease in the skin. The second step is the conversion of this nanophase into a macroemulsion for transporting the grease out of the skin and subsequently away from it. This knowledge led us to the development of a novel class of degreasing agents in a more eco-friendly degreasing process.