Context: Leather products are known for being a luxury purchase, dependent on consumers' preferences and disposable incomes. Since consumers are becoming more informed about the environmental impact of the products they purchase, leather has come under the spotlight leading to a demand for sustainably manufactured leather.
Research Backgorund: The research on leather manufacturing technology aimed at reducing pollution has mostly focused on tanning agents, notoriously known for their environmental harm. While chromium tanning offers several advantages like softness, suppleness, and water resistance, the environmental risks it poses, especially when chromium (III) converts to chromium (VI) and contaminates water bodies, are a cause for significant concerns. As a result, this issue has resulted in over 2,000 patented inventions related to tanning in the past decade. However, a deeper analysis of the research landscape in leather manufacturing indicated research hotspots within the post-tanning and finishing technology domain.
The Elephant in the House: Manufacturing of leather consists of 4 main processes – Beamhouse, Tanning, Post-tanning, and Finishing. Post-tanning and finishing are the value-addition processes that add texture and structured properties to the tanned leather as well as sensory and color properties. While all four processes contribute significantly to solid waste generation, the latter two steps contribute the most towards volatile organic compounds emissions (VOCs), toxic crosslinking agents, and non-biodegradable resins.
Post-tanning and finishing processes consume an average of 360.2 kg of chemicals per ton of leather manufactured, and since significant amounts of water are utilized during the process, most of the chemicals are released as effluents along with the water. Solvents used for degreasing and finishing are a source for exposure to VOCs with nearly 30 kg emitted per ton of leather manufactured if pollution prevention measures are not implemented.
The industry has therefore been investing in the development of chemicals that are sustainably sourced, can be recycled back into the production loop and have a low impact on the environment when released as effluents.
Solutions: Emerging Players developing novel post tanning and finishing technologies. #LeatherChemicals
Industry players, start-ups, and research institutes are investing in research towards sustainability in the leather industry. The direction of this research is mainly towards two opposing views – on one hand, regulations and legislative efforts have launched initiatives pushing decarbonizing and cleaner manufacturing within many industries, including leather. On the other hand, consumer awareness is dictating shifting trends towards alternative leather, leading to traditional leather companies driving up innovation and high-quality product investments.
Stahl
Stahl, a company based in the Netherlands, has created a unique leather finishing technology that utilizes rapeseed oil instead of crude oil derivatives. The technology is named Polymatte, and employs a polyurethane-based dispersion method to achieve a smooth and, like its name suggests, a matte surface during the leather's film forming and drying stages, eliminating the need for fillers. Polymatte offers several advantages, including resistance to solvents, oil, hydrolysis, and oxidation, while producing low VOC emissions. Stahl emphasizes open innovation and renewable feedstocks as part of their strategy, leading to the development of technologies like Polymatte.
Evolved By Nature
Activated Silk L1 Biofinishing System is a biotech-based leather finishing method developed by Evolved By Nature, a US-based company. The technology is a pure liquid silk protein derived from natural silkworm cocoons. The system consists of a topcoat, base coat, and other auxiliaries added as per the requirement of performance enhancement. The topcoat has 0% Polyurethane (PU), while the base coat has reduced use of PU. The entire system is certified to be PFAS-free and uses a reduced number of cross-linkers. Evolved By Nature has already begun selling this technology to tanneries around the world.
Guangzhou Guanzhi New Material Tech
The Chinese chemical enterprise has developed a patented technology that takes a different approach to recycling the waste waterborne polyurethane and dispersion to retrieve its resin form, which can be used as a leather finishing agent. By adopting circular sustainability, the environmental impact per ton of leather produced is reduced.
University of Naples Federico II
Research from an Italian university has developed a leather finishing system that incorporates green technology and utilizes tanned waste through enzymatic treatment, hence having a circular production flow as well. The work was funded by the Italian Ministry for University and Research (MUR).
Anna university
An Indian university in Chennai has developed a fat liquoring agent derived from fish waste, demonstrating superior performance when compared to traditional fat liquors. Research shows a significant pollution reduction, as indicated by the chemical and biochemical oxygen demand of the effluent from the fatliquoring process
UFRGS - Universidade Federal do Rio Grande do Sul
The Brazilian research institute has developed a fungi-based dye. The dye is sustainably sourced as it is synthesized by the fungi using bovine fur, an agro-industrial residue designated to a landfill, as feedstock. The dye is biodegradable, suitably durable, and has enormous potential for commercial-scale production with minimal environmental impact.
Next Step: Manufacturing operations across industries have placed environmental sustainability as one of their top priorities, which applies to the leather industry as well. Leather manufacturers need to gear up, set eco-friendly systems in place, and develop a roadmap to achieve net zero (if it does not exist already!). Investing in research on sustainable manufacturing practices is a crucial step as part of this process. Innovative, cost-effective, and eco-friendly manufacturing processes are being developed that would change traditional leather production practices, making it imperative for companies to be a step ahead and develop an understanding of the research landscape.