The invention concerns a process for tanning hide to obtain leather. The general process for obtaining the intermediary wet bleu stage comprises the following steps : a) a picking step with acid and salt, followed by b) a tanning step with chromium salt, followed by c) a basification step. The invention is characterized in that between step b) and c), a re-acidification step with organic acids is added. In particular the acids are selected from glutaric acid (GA), 2-Methyl glutaric acid (MGA), succinic acid, ethyl succinic acid (ESA), adipic acid (AA), maleic anhydride, fumaric anhydride, tricarboxylic acids, hydroxycarboxylic acids, and mixture thereof. This invention enables an increase of the up-taking of the re-tanning products and provides leather of improved mechanical properties.
展开▼
