Effect of Calcium in Delimed Hide on Leather Quality

Abstract

The efficient removal of calcium from delimed hide is essential to leather quality, but few reports have elaborated on how residual calcium in delimed hide affects leather quality. In this study, four delimed hides containing different calcium content were first prepared by using ammonium sulfate and sodium gluconate. Energy dispersive X-ray spectrometry results showed that the atomic percentages of calcium on the grain surfaces of the four delimed hides were 8.17%, 4.82%, 2.34%, and 0.25%, respectively. The bating, chrome tanning, and post-tanning performances of the four delimed hides were then analyzed to evaluate the effect of calcium in delimed hide on leather quality. Results showed that the removal efficiency of non-collagenous protein from hide in enzymatic bating, the evenness of chromium distribution, the shrinkage temperature of wet blue, and the physical properties of crust leather all increased as the calcium content of delimed hide decreased. Furthermore, efficient calcium removal from the grain surface of delimed hide played a key role in the color brightness and uniformity of wet blue and crust leather. The results draw our attention to the importance of considering the effectual removal of calcium from delimed hide for obtaining high-quality leather.