From Leather Wastes back to Leather Manufacturing: The Development of New Bio-Based Finishing Systems

The leather industry is currently between two opposing paths: on the one hand, recent legislative trends in terms of the eco-sustainability of industrial processes are leading leather manufacturing towards the development of cleaner production methods; on the other hand, the spread of new alternative materials to leather is driving the leather industry to improve its competitiveness by developing new innovative and high-quality products. Leather finishing is one of the most important phases of leather production, and is capable of improving its quality and organoleptic properties. However, this phase is characterized by the use of polluting chemical products, such as volatile organic compounds, potentially toxic crosslinking agents, and hardly biodegradable resins. In this context, this research work aims to develop a finishing formulation capable of giving leather the durability and quality properties required by the market, while at the same time, being eco-sustainable. Specifically, the aim of the present work is to suggest a new finishing formulation in terms not only of green technology but also of a circular production flow, by recovering solid leather wastes. The developed finishing system is based on the application of collagen, extracted from tanned wastes through an enzymatic treatment, to be cross-linked and bound to the leather surface. This new bio-based leather finish is compared to a resin-based leather finish, and shows the same quality standards as those requested by the market.