Chrome-free tannage by sequential treatment with synthetic resins and aluminium or titanium

Severe limitations imposed on the water authorities in developed countries on the discharge of chromium in tannery effluents have developed a keen int erest to find an alternative to chrome tanning. A sequential tanning proced ure using synthetic resins prepared from urea or dicyanidiamide, phenolic c ompounds, sulphonated phenolic compounds and formaldehyde followed by maske d aluminium or titanium salt has been developed. The method has produced wh ite full leather having a shrinkage temperature up to 100 degrees C. Leathe r produced by the method requires higher levels of fatliquor and can withst and relatively severe dye bath conditions.