Abstract

A vegetable—zinc combination tannage on lambskin has been studied, with special attention being given to the intended final product, in an attempt to optimise the process. This kind of chrome-free tannage enables us to obtain leathers with a shrinkage temperature above 100°C.

The research was carried out in two stages. First, the possible influence of several parameters was studied with the help of an experimental design of the 2,.. type. These parameters included the extract and zinc salt used, temperature, whether or not tannage had taken place in the same bath and the basification system.

In the second stage research followed a centralised experimental design of the second order. This ought to enable us to assess the influence of the vegetable extract (mimosa, quebracho, chestnut) and zinc sulphate offers on the final product.

The conclusions of the final stage were reached by means of analysis of the response surfaces obtained for the main physical and chemical properties involved.