Abstract

Chrome tanning is the main tanning leather method. However, the absorption of chromium is incomplete and residues are present in waste liquors thus polluting the environment. Moreover, Cr3+ will oxidise into carcinogenic Cr6+ under certain conditions. Here we a present a novel chrome-free tannage. The calix[4]arene was synthesized using tert-butyl phenol and formaldehyde as raw materials. The calix[4]arene was then sulfonated with concentrated sulfuric acid. The structure was characterised by FTIR and 1HNMR. The sulfonated calix[4]arene was applied in goatskin tanning. The results showed that the sulfonated calix[4]arene had a tanning effect. The physical and mechanical properties of the tanned leather were better than those of conventional chrome-tanned leather.