ALUMIMIUM-VEGETABLE COMBINATION TANNAGE FOR PRODUCTION OF SHOE UPPER LEATHERS

Abstract

Leather processing involves conversion of putrescible raw skins/ hides into
useful material called leather by the process having common name ‘tanning’.
Development of cleaner leather processing technologies is imperative for the
sustenance of the tanning industry. In the present study, a combination
tanning system based on Henna–Aluminum tannage for the production of
upper leathers as a cleaner alternative is presented. Extract from the leaves of
widely distributed lawsonia inerims (Henna) from Sudan has been evaluated
for its tanning characteristics in a combination tanning system based on
Henna and Aluminum sulphate. Both tanning methodologies henna followed
by Aluminum (Henna-Al) and Aluminum followed by Henna (Al-Henna)
have been attempted at concentration of 2% Al2O3. All combinations tanning
systems resulted in leathers with shrinkage temperature above 90oC.
However, Al-Henna leathers tanned using 2% Al2O3; followed by 20% henna
resulted in shrinkage temperature of 95oC, and Henna (20%) followed by
Aluminum (2% Al2O3) resulted in leathers with shrinkage temperature of
97oC. The uptake of henna in Henna-Al tanning system with Henna (20%)
followed by Aluminum (2% Al2O3) has been found to be better than the
tanning system of Al-Henna. These leathers showed opened up, split compact
fibre structure, indicating that the tanning process did not bring about any
major change or destruction on the fibre structure of the leathers. The
combination system provides significant reduction in the discharge of total
dissolved solids in tanneries wastewater. Henna-Al combination system
resulted in leathers with good organoleptic and strength properties. The work
presented in this paper established the use of henna aluminium combination
tanning system as an effective alternative cleaner tanning methodology.