Preparation and properties of maleopimaric acid-based polyester polyol dispersion for two-component waterborne polyurethane coating

An anionic polyol (MPP) dispersion was prepared by introducing maleopimaric acid (MPA) into polyester polyol chain through esterification reaction. The influences of catalyst content, molar ratio of alcohol to acid, 5-sulfoisophtalic acid sodium salt (5-SSIPA) content and MPA content on particle size, stability and rheological property of MPP dispersion were investigated. The optimized conditions for the synthesis of stable MPP dispersion were identified as 1 wt% catalyst content, 1.4:1 molar ratio of alcohol to acid, 2.86 wt% 5-SSIPA content, and 15 wt% MPA content. The MPP dispersion was then applied to the preparation of a novel maleopimaric acid-based two-component waterborne polyurethane (2K-WPU) coating. Incorporating MPA into MPP dispersion leaded to the maleopimaric acid-based 2K-WPU coating with improved tensile strength, gloss, pencil hardness, water resistance and ethanol resistance. The results suggested that MPP dispersion provided a potential application in the field of 2K-WPU coating.