Self‐Repairing Coating with Excellent Mechanical Properties by Compatibility Epoxy Resin‐Loaded Polyurea Formaldehyde Microcapsule

Polymer coating is one of the most widely used methods to inhibit metal corrosion. However, the continuous generation and aggregation of microcracks inside the coating eventually lead to cracking or damage at the macro level, which greatly damage the mechanical and protective properties of the coating. Therefore, the polyurea‐formaldehyde microcapsules loaded with epoxy resin repair agent in the resin matrix are mixed and dispersed. When microcracks are generated inside the coating, the extension and expansion of microcracks would cause the microcapsules to rupture, thereby releasing the repair agent. The repair agent fills the microcracks under the siphon effect and then repair the microcracks, thereby restoring its mechanical properties, corrosion resistance, and appearance. The weight fraction of microcapsules on the internal bonding strength and anticorrosive performance of the scratched samples are studied under tensile test and salt spray condition, which reveal the coatings with microcapsules in the range of 15–20 wt%, demonstrate the best performance. It is worth noting that the research provides some theoretical support and practical guidance for the study of metal anticorrosive coatings with self‐healing function.