Abstract: This invention relates to urethane acrylic hybrid polymer dispersion with robust dry/wet adhesion and the basecoats prepared therefrom for automotive applications. In this system, the polyurethane dispersion (PUD) prepolymer is based on a combination of polyols and aliphatic diisocyanates. The acrylic portion is based on (meth)acrylated monomers. A combination of this hybrid polymer dispersion and other resins having defined glass transition temperature (Tg) values, organic and/or inorganic rheology modifiers, and different additives including pigment, dispersant, and defoamer are used to prepare waterborne basecoats having modified appearance and performance. The final coatings show excellent dry/wet adhesion to the primer for automotive applications.

Abstract: A waterborne basecoat includes a rheology package having two or more rheology modifiers selected from the group of an ethylene vinyl acetate copolymer wax emulsion, an alkali swellable acrylic copolymer emulsion, a silicate layered clay, and a hydrophobically modified ethylene oxide urethane; a resin system comprising two or more waterborne dispersion resins selected from the group of a urethane-acrylic hybrid resin dispersion having a medium Tg of about 15 to about 35° C., a urethane modified Aldehyde/ketone emulsion having a high Tg of more than about 100° C., and a polyurethane dispersion having a low Tg of less than about ?20° C., and a pigment. The pigment may be metallic or non-metallic and may be selected from organic or inorganic pigments. The rheology package and the resin package may be optimized to accommodate properties commonly associated with different types of known pigments.