Abstract

Increasing environmental consciousness has impacted on the pollution caused by chrome tanning which has become a difficult problem requiring an urgent solution leading to studies on chrome-free tanning systems. A new zirconium-oxazolidine combination tanning system has been developed. The amount of zirconium-oxazolidine has been optimized at 2.5% and 3.0% (based on limed weight of skins). The influence of ligands on the shrinkage temperature (Ts) of leathers has also been studied and zirconium-oxazolidine combination tanned leathers showed Ts above 92°C. Zirconium-oxazolidine tanned sheep garment leather is much whiter than the chrome tanned, being close to the standard whiteness. The degradation rate of zirconium-oxazolidine combination leather is 18.83% after 45 days soil burial and is much quicker than that of chrome tanned leather which is 5.78% after 45 days. SEM observation revealed that the non-degraded surface structure was more regular than that of chrome leather degraded for 30 days. The zirconium-oxazolidine combination tanned leather degraded more easily than chrome leather, which is of benefit for the sustainable development of the leather industry.