Effect of Number of Impregnations of Microberlinla sp with Microcapsule Emulsion on the Performance of Self-Repairing Coatings on Wood Surfaces

Abstract

Embedding melamine-formaldehyde (MF) resin-coated shellac microcapsules in waterborne coatings can extend the service longevity of waterborne coatings on a wood surface to a certain extent. Due to the content limitation of self-repairing microcapsules in waterborne coatings, the effective self-healing performance time is short. With the aim of improving the self-repairing properties of self-repairing coatings on the surface of a Microberlinla sp substrate, a more effective self-healing mechanism was achieved by impregnating the ebony wood substrate several times with an MF resin-coated transparent shellac-rosin microcapsule emulsion. After the impregnation of the ebony boards with microcapsules, a waterborne acrylic resin coating containing 3.0 wt.% transparent shellac microcapsules was applied to the surface of the wood boards. The influence of the number impregnations on the surface coating’s physical properties, chemical properties, and self-repairing properties was explored. The results showed that the hardness of the surface coating on the ebony boards changed little under different numbers of impregnations. With the increasing number of impregnations, the surface coatings’ adhesion and impact strength slowly increased, the chromatic difference value was increased, and the roughness first increased and then decreased. Impregnating ebony boards with the microcapsule emulsion contributes to enhancing the aging resistance and repair performance of surface coatings on the ebony boards. When the number of impregnations was eight, the width change rate of cracks on surface self-healing coatings was 28.4%, which suggested the best repair performance among all samples. By impregnating the wood substrate with the self-healing microcapsule emulsion, the effect of the interaction between microcapsules and wood on the self-repairing properties of the surface coating was studied, contributing to the theory for further improving the self-repairing properties of waterborne coatings on wood surfaces and promoting the application and development of self-healing microcapsules.