A Novel Route to Emulsifier-free, Waterborne Hydroxyl Functional Polyacrylate with Low VOC Level and its Application in 2K-WPU Coatings

A novel two step polymerization method which combined the advantages of both solution polymerization and emulsion polymerization was proposed for emulsifier-free, waterborne hydroxyl functional polyacrylate with low VOC level. The obtained resin provided a good appearance and moderate viscosity. The structure of resins was characterized by fourier transfer infrared (FTIR), dynamic light scattering (DLS), differential scanning calorimeter (DSC) and gel permeation chromatography (GPC). The hydroxyl polyacrylate dispersion (PAD) named as PAT-2 was cured with hydrophilically modified polyisocyanate curing agent (Bayhydur XP 2655) to obtain two component waterborne polyurethane (2K-WPU) coatings. FTIR was employed to investigate the structure of the cured coatings. The 2K-WPU coatings showed high gloss and hardness, good adhesion, excellent impact resistance and superior water and chemical resistance, which denotes wide application on industrial anti-corrosive coatings fields.