Bioinspired Functional Group Integration Strategy for Multi-Functional Adhesive with Strength, Polymer Adhesion, Metal Adhesion, Solvent Resistance, and Persistent Adhesion

Metal flexographic printing plates typically consist of a photosensitive layer, an adhesive layer, and a metal substrate. Given the requirements of plate preparation and pattern printing processes, the adhesive layer demands excellent mechanical strength, robust adhesion to both metals and polymers, solvent resistance, and long-term durability. Inspired by the mussel foot silk protein structure, this study synthesized an adhesive by integrating alcohol hydroxyl, polyphenol, C═C, and amino ester groups into a single molecular chain via click chemistry. The adhesive demonstrated a shear strength of 1.67 MPa on an iron substrate and a 180° peel strength of 1.54 N/mm on metal flexographic printing plates, representing enhancements of 129% and 178% over the commercial epoxy resin (EPR) adhesive, respectively. Moreover, after 12 h of immersion in water, boiling water, ethanol, and DMF, the shear strength retention rates were 94.6%, 80.8%, 83.8%, and 81.4%, respectively. Following 28 days of storage at 25 °C, the 180° peel strength retention rate remained at 87%. This mussel-inspired group-integration strategy thus offers an approach to preparing multifunctional adhesives tailored for the flexible printing industry.