Degreasing of hides and skins

Back to Subsection DC leather

General description

Degreasing is most relevant in processing sheepskins, where the natural fat content is about 10 – 20 % of dry weight. Degreasing as a separate process step is not usual for bovine hides. The nature of this fat makes it difficult to remove because of the presence of glycerides and a high melting temperature.

Excessive amounts of grease in the skin may interfere with uniform penetration of tan or dye, causing difficulties in the finishing processes and creating dark and greasy patches on the finished leather. Degreasing of greasy skins is particularly important before chrome tannage as the chromium salts can react with the greases and form insoluble chromium soaps, which are very difficult to remove subsequently [50, Sharphouse 1983].

The three different methods commonly used for degreasing are:

1. degreasing in an aqueous medium with an organic solvent and a non-ionic surfactant

2. degreasing in an aqueous medium with a non-ionic surfactant

3. degreasing in a solvent medium.

Source: Joint Research Centre, Best Available Techniques (BAT) Reference Document for the Tanning of Hides and Skins, 2013

Back to Subsection DC leather