Harnessing Leather Waste in Low‐Temperature‐Curing Waterborne Adhesives for Leather With Thermal Energy Storage Properties

ABSTRACT

Conventional solvent‐borne adhesives used in leather processing raise significant environmental concerns due to high volatile organic compound (VOC) emissions and reliance on toxic solvents. The temperature‐sensitive nature of leather precludes the use of high‐temperature curing waterborne adhesive systems. Furthermore, leather waste (LW) accumulation presents serious environmental threats. To address these challenges, a sustainable waterborne composite adhesive is developed via aza‐Michael and amine‐epoxide reaction pathways, enabling low‐temperature curing at 40°C–50°C. The incorporation of PEGMA, GMA, and stearyl methacrylate (SM) facilitates the preparation of stable emulsions that cross‐link efficiently with LW, yielding GPS‐LW100, GPS‐LW150, and GPS‐LW200 composite adhesives. Mechanical evaluation reveals T‐peel strengths of up to 0.87–1.22 N/mm and lap shear strengths of up to 427–622 kPa, meeting the performance (0.70 N/mm and 390 kPa, respectively) of commercially available synthetic rubber‐based adhesives. Thermal analysis confirms broad stability from −23°C to 240°C, and the adhesives exhibit phase change material (PCM) behavior, offering potential for passive thermal regulation. Solar‐assisted curing further reduces the environmental footprint without compromising performance. This organic solvent‐free, low‐energy platform presents a scalable, high‐performance alternative for leather processing, footwear, and thermoregulated textile applications.