Preparation of excellent-water-resistance water-borne alkyd/acrylic hybrid coatings with varied maleic anhydride content

Water-borne alkyd/acrylic hybrid resins with varied maleic anhydride (MA) content were synthesized from the reaction between alkyd intermediate (AK) and maleic anhydride modified acrylic prepolymer (AC) followed by neutralization of carboxyl groups with triethylamine. Water-borne alkyd/acrylic hybrid resins were characterized by nuclear magnetic resonance (NMR), infrared spectrum (IR), transmission electron microscope (TEM), gel permeation chromatography (GPC), laser diffraction particle size analyzer, rheometer and thermogravimetric analysis (TGA). In addition, air-drying water-borne coatings were prepared using the above-mentioned dispersions and their coatings properties were evaluated. The results showed that the microstructure of the water-borne alkyd/acrylic hybrid dispersion was loose cotton type, which induced the accessibility of fatty acid chains to oxygen is unimpeded, therefore, higher cross-linking density would be obtained and resulted in the coating with optimum MA content exhibited excellent physical properties and water resistance, up to 32 days, which is better than the water resistance of all water-borne alkyd coatings or modified water-borne alkyd coatings reported up to now, and also better than the water resistance of the commercial water-borne alkyd/acrylic hybrid coating.