Abstract

The manufacturing processes of leathers and skins are, at the present time, undergoing a change as a result of the demands of environmental pressure groups. The chrome-free tanning processes such as vegetable, aluminium, and oil do not meet the needs of all the kinds of leather on the market. Present tendencies point to a reduction in the chrome offer or to an exhaustion of the chrome itself. In the light of the environmental tendencies it may well be that, in the future, chromium may be declared a hazardous metal. This event would have serious implications for the tanneries as far as the elimination of waste water and solid waste is concerned. The solution, we believe, does not lie in reducing the usage of chromium but in the avoidance of its use. In this connection, processes based on synthetic compounds, other metals (copper, zirconium, aluminium, titanium,)^1,2,3,4,5 aldehyde compounds (glutaraldehyde, formaldehyde, glyoxal, oxazolidines), polysilicic acids, polyamine derivatives and polycarboxylic acids have been reported. The use of chromium, albeit to a small degree, is still necessary in some of these processes.