Use of Polyols for the Eco-Friendly Leather Tanning: A Sustainable Choice

Leather tanning is a chemical process of fundamental importance for the national territory, requiring the use of chemical agents to establish stable bonds with the collagen matrix of animal hides. This sequence of treatments prevents the putrefaction of the animal's skin, converting it into stable leather and improving the chemical-mechanical properties of the final product. Alkaline chromium salts are still the main tanning agents used for this chemical treatment, but their use poses considerable environmental drawbacks. In this context, the INCANTO project ("INnovative Tanning Through New Types of Optimized Polyol-Based Tanning Agents") explores the synthesis and use of polyglycerols as a sustainable and metal-free alternative to chromium salts for leather tanning. Polyglycerols have been produced from glycerol feedstock, the main by-product of biodiesel production, thus improving the development of a circular economy approach in the biodiesel production chain. Tanning tests have shown promising results for short linear polyglycerins, and our attention is now focused on further increasing their molecular weight to evaluate possible correlations with tanning performances.