Abstract

The literature of aluminium tanning has been reviewed particularly that relating to the production of leathers with shrinkage temperatures greater than those found in alum tawed leathers. Reactions between aluminium salts masked with polyphenolics, both simple and those found in the natural organic tannins, have been investigated. It has been established that at least two trihydroxyaryl units per molecule are required to obtain shrinkage temperatures in excess of 100°C. The preferred method of application is to use the phenolic compound as a pre-tannage, which is followed by application of the aluminium salt.