Acrylic Hot-Melt Adhesives Containing Dynamic Covalent Cross-Links

Hot-melt adhesives (HMAs) offer several advantages over solvent-based alternatives, such as lower environmental impact and faster processing, yet their mostly thermoplastic nature often limits mechanical strength and solvent resistance. To address this limitation, poly(n-butyl methacrylate-co-itaconic anhydride) copolymers were designed for facile cross-linking through anhydride ring-opening with alcohols, enabling a dynamic monoester-anhydride exchange within the adhesive. The resulting networks exhibit substantially improved solvent resistance and mechanical performance, resulting in a 10-fold increase in lap-shear strength compared to a thermoplastic reference. Moreover, complex-viscosity measurements reveal a sharp viscosity transition within the typical HMA processing window (120-180 °C), enabling efficient substrate wetting during application while maintaining mechanical integrity at service temperatures. Overall, this work introduces an itaconate-based acrylic platform for dynamically cross-linked HMAs and expands the applicability of reversible anhydride chemistry in adhesive materials.