Tanned leather composition and preparation method thereof

Generally, the leather re-tanned by a composition of a synthetic tanning agent is utilized to enhance the properties such as richness, density of rugged face, smoothness and roundness of rugged face. Multiple chemicals for preparing such synthetic tanning agent are toxic and slowly biodegradable. Furthermore, some synthetic tanning agents are combined to obtain the required properties in an industry practice. This invention discloses a synthetic tanning agent employing natural and proteinic waste material, and reveals that the tanning agent has the properties such as better fiber lubrication, filling of loosened extremity, flexibility, shape retentivity and production comfort to the leather in the situation of not being combined with other synthetic tanning agents.