Strong Thermo-Tolerant Urushiol Glycidyl Ether-Crosslinked Acrylic Pressure-Sensitive Adhesive

Conventional acrylate pressure-sensitive adhesives (PSAs) often soften, melt, or lose tackiness under high-temperature conditions, leading to performance failure. To address this challenge, we exploited the molecular structural advantages of natural urushiol to design and synthesize a bio-based crosslinker, urushiol glycidyl ether (UGE). Through the ring-opening esterification reaction between the epoxy groups of UGE and the carboxyl groups of acrylic acid (AA), a three-dimensional crosslinking network was constructed within the acrylate PSA matrix. By modulating the AA-to-UGE molar ratio, we systematically investigated the effect of crosslinking density on adhesive performance, heat resistance, and rheological behavior. The optimized formulation (PSA-A1-U1) exhibited a 180° peel strength of 8.34 N/24 mm, an initial tack level of 6, and a tack retention time exceeding 72 h. After preconditioning at 150°C for 2 h, no adhesive residue was observed, and the SAFT (shear adhesion failure temperature) exceeded 225°C. This work demonstrates a novel strategy for designing heat-resistant, high-performance PSAs and broadens the application prospects of natural urushiol derivatives in functional polymers. Highlights A three-dimensional crosslinked PSA has been developed. The crosslinked PSAs exhibit high peel strength. The adhesive residue was improved. The SAFT of crosslinked PSAs exceeded 225°C.