This article describes a technology for the thermoplastic treatment of collagen. Based on limed, untanned cattle pelts a fine powder, termed Thermoplastic Collagen (TC) is produced, which can be processed using conventional thermoplastic techniques. Central step in the production of TC is the partial denaturation of collagen, which was achieved by four different methods. Extrusion of TC at temperatures below 100 degrees C is possible after addition of 3060% water as plasticizer. In order to maintain permanent flexibility and reduce tackiness, glycerol and stearic acid are used as additives. Shear and elongational viscosities of TC-water-mixtures decrease with the shear rate which is consistent with the behavior of thermoplastic materials. The power law can be applied, yielding power law indices of 0.150.35. The viscosities are more distinctly influenced by raw material and water content than by temperature or glycerol content. Material properties of the extrudates are described and compared with the starting material. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013