Eco-Friendly Leather Tanning with Polyglycerols: Toward the Development of a More Sustainable Process

Leather tanning is an important chemical process for the national industrial sector, requiring chemical agents to stabilize the collagen matrix of animal hides. These treatments inhibit biological degradation of the raw material, converting hides into durable leather, at the same time improving the chemical and mechanical properties of the final product. At the present, alkaline chromium salts are the most commonly employed tanning agents; however, their use raises serious environmental and toxicological issues. Within this framework, the INCANTO project (“INnovative Tanning Through New Types of Optimized Polyol-Based Tanning Agents”) explores the development and application of polyglycerols as sustainable, metal-free alternatives to traditional chromium-based systems. Polyglycerols are produced from glycerol, the primary by-product of biodiesel manufacturing, thereby promoting a circular economy strategy. Preliminary tanning tests have demonstrated encouraging results for short-chain and linear polyglycerols, and current research efforts are therefore focused on evaluating the tanning performance of higher–molecular weight polyglycerols.