The degreasing mechanism

Efficient degreasing was found to be closely connected to the three-phase state and hence to the ultra-low interfacial tension between water and oil [170]. The so far unidentified mechanism of degreasing of animal skins could be understood and explained. Correlation of results obtained from phase behaviour measurements and degreasing experiments revealed that Eusapon OD shows the best degreasing performance and lead to the clarification of the four-step process of degreasing as shown in Fig. 10.13 [171]. The first step is the penetration of the surfactant into the skin. In a second step the natural fat is solubilised. A microemulsion phase coexists with a fat- and a water-excess phase and the interfacial tension between water and oil is ultra-low. On the surface of the skin dilution of the microemulsion with pure water, i.e. reduction of the salt concentration in the float, leads to the formation of a stable emulsion via shearing. The stable emulsion prevents the deposition of the fat on the skin and enables the transport of the natural fat away from the skin. 

SE would like to thank for the performance of the degreasing experiments in the BASF beam house. 

Solans, C. and Kunieda, H. (1997) Industrial Applications of Microemulsions, Surfactant Science Series 66. Marcel Dekker, New York. 

Kahlweit, M., Strey, R., Haase, D., Kunieda, H., Schmeling, T., Faulhaber, B., Borkovec, M., Eicke, H.-F., Busse, G., Eggers, F., Funck, T., Richmann, H., Magid, L., Soderman, O., Stilbs, P., Winkler, J., Dittrich, A. and Jahn, W. (1987) Howto study microemulsions. /. Colloid Interface Scu, 118(2), 436-453. 

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