Preparation and Self-Repairing Properties of MF-Coated Shellac Water-Based Microcapsules

Abstract

A self-repairing microcapsule was prepared by emulsion polymerization using melamine formaldehyde resin (MF) as wall material, and a mixture of shellac solution and water-based coating as core material. The orthogonal experiment was carried out through five factors and four levels. The effects of Wcore:Wwall, Wemulsifier:Wcore, stirring rate, Wshellac:Wcoating, Wemulsifier solution:Wcore on the output and coverage rate of microcapsules were studied. The stirring rate has a great influence on the preparation process of the MF-coated shellac water-based microcapsules. When the Wcore:Wwall is 0.8:1, Wemulsifier:Wcore is 3:100, stirring rate is 600 rpm, Wshellac:Wcoating is 1:1, Wemulsifier solution:Wcore is 9:1, the prepared microcapsules have the best shape and size. With the increase in concentration of microcapsules, the color difference and gloss of paint film decreased gradually. The tensile strength, scanning electron microscopy (SEM), infrared spectroscopy and repair effects of the paint film were analyzed. When the concentration of microcapsules was 5.0–10.0%, the comprehensive performance of the paint film was better, providing a technical reference for the self-repairing coatings.