Clean Hair Removal Liming On Theory And Technology Applications

Diminishing pollution and improving quality are two most important problems, which impact the development of leather industry in China. Liming process is famous for both its pollution and its importance in leather manufacture. This paper is to solve the pollution and improve leather quality by the detailed research of liming process.The relation between unhairing effect and residual sodium sulfide in limed water was studied to lead to a complete solution of sulfide, lime and organic substance pollution in unhairing and liming process. The cleaner technology explored in this paper could eliminate sulfide both in the waste liquor and the limed hide. Suspended solids, CODfr and protein in the waste liming water were decreased by 85%~90%, 80-85% and 80-90% separately, and the color and smell of the effluent were also deduced to great extent. The ratio of reaction between hydrogen peroxide and sodium sulfide, the influence of catalyst and other factors were investigated in detail. At the same time the method of protein recycling and elimination of lime pollution were also studied to obtain the ideal conditions.In investigation of swelling and inhibition of collagen, several questions were set out which could not be explained by the existing theory of collagen swelling. By introducing equilibrium and all-round aspects in this paper, traditional Donnan equilibrium theory and the static electricity repelling theory were modified to elucidate all the phenomena of hide swelling and inhibition.In this paper it was found that the collagen degradation was decided not only by the kind and amount of acids and alkalis, but also the swelling degree of hide. Collagen degradation increased in proportional to swelling degree. According to this conclusion, unswelling liming technology was brought forth, and it was demonstrated that liming chemicals was much easy to penetrate into the hide and limed hide had less lime crease in this process, the resultant leather had good elasticity, less loose grain and less region difference.The cleaner unhairing and liming technology was applied in pig garment leather and sheep garment leather. The physical and chemical properties of the resultant leather were tested, and the fiber separation was examined by SEM and Vis microscope analysis. All the results showed that this cleaner liming process is...