Preparation New-type Leather Degreasing Agent With Leather Wastes

With the developing of the environmental values of Circular Economy and Green Chemistry,the leather industry is facing the challenge of sustainable development,and how to recycle leather wastes is become a question of common concern at home and abroad.The major constituents of leather wastes is protein,which is a kind of valuable resource.In the past the leather wastes was discarded and become a serious environmental pollution.Therefore, reclamation leather wastes is be of important mean to the environment and society.The study focus on using two kinds of leather wastes,chrome shaving and cowhair,to prepare leather degreasing agent separately. On the basis of predecessors.like use shaving wastes to prepare retanning agent, stuffing bulking agent and fatliquoring agent and so on, this thesis first proposed preparation leather degreaing agent with shavings.At first, the major factors, alkali dosage, hydrolyzing temperature, hydrolyzing time,which have effect on hydrolyzation was discussed.The optimum condition of the shaving hydrolyzation was as follows:sodium hydroxide6%, hydrolyzing time 6h, hydrolyzing temperature 100?.Furthermore,oleoyl carboxylates was obtained by the reaction of oleoylchloride and the shaving hydrolysis products,then the surface tension,foaming power and emulsifying power of the synthetic oleoyl carboxylates were tested, the results suggest that the synthetic surfactant has the ability of reducing the solution surface tension and strong foaming and emulsifying power and it is proved that the oleoyl carboxylates which was syntheticed by leather shaving hydrolyzation can be used in leather degreasing agent. Then a new kind of degreasing agent was formulated, which the synthetic oleoyl carboxylates was as the principal components.The new agent has outstanding performance in the experiment of simulate degreasing and pigskin degreasing,the rate of degrease was next to 80%.The cowhair which was emerged after the hair-saving unhair method in leather-making was never studied before. When used cowhair as crude material of hydrolyzition to synthetize oleoyl carboxylates,the result show big differences compared with using shaving and to formulate deagreaing agent was not available.Even so,there were still some constructive conclusions on cowhair hydrolyzation and decolor. alkali dosage was the most important factor on cowhair hydrolyzation,and the hydrolyzing temperature effect less,the optimum condition of the cowhai hydrolyzation was as follows:sodium hydroxide6%,hydrolyzing time 8h, hydrolyzing temperature 100?, and the optimum condition of the cowhai decolor was as follo ws:oxyful 3mL/25mL,time 40min, temperature 70?,pH 10.0. There were some deficiencies in decolor,which caused by different kind of cowhair,the high the decolouring ratio and low amino acid loss rate can not be got at the same time and further experiments was needed.