MODERN TANNING CHEMISTRY

The range of chemistries used for tanning leather is reviewed; traditi onal methods of tanning are explained and the newer processes are desc ribed. The areas of tanning include: vegetable tanning with plant poly phenols, mineral tanning with metal salts, in particular chromium(III) , oil and aldehyde tannages, synthetic tanning agents and organic tann ages based on natural polyphenols or synthetic organic oligomers. The fundamental nature of the tanning reaction and the origin of hydrother mal stability are discussed.