Preparation of sulfated/sulfonated castor oil through an eco-friendly process and its application in leather

Today, the world is calling for conserve water and environmentally friendly production. This study examines the feasibility of producing fatliquor from castor oil using the sulfur trioxide process instead of the traditional concentrated sulfuric acid process. Fatliquor, which enabled the leather fiber to lubricate, was prepared by sulfated castor oil with sulfur trioxide at a particular temperature. Moreover, five types of anionic fatliquors were prepared by changing the SO₃/castor oil ratio. Physical and chemical studies of fatliquoring agents such as viscosity, pH, solid content, organically combined sulfuric anhydride, iodine value, saponification value, and emulsifying stability were determined before its application on leather. The effects of sulfonation degree and ester bond retention on the characteristics of fatliquored leather were investigated. The softness, tensile strength, elongation at break, and tear strength of the best experimental leather are 12.6%, 18.1%, 25.0%, and 172.6% larger than the commercially available product, respectively. Too much hydrolysis of ester bonds will cause the softness of the fatliquored leather to deteriorate. In addition, the experimental emulsion is easily biodegradable.