AQUEOUS DISPERSION OF AT LEAST TWO POLYMER RESINS AND AQUEOUS COATING COMPOSITION CONTAINING SAID RESINS FOR APPLYING TOPCOAT Russian patent published in 2018 - IPC C08G18/62 C09D151/08 C09D167/02 C09D161/28 C09D175/14 B05D7/14 B05D7/16 B05D7/26 B05D1/36 

FIELD: chemistry.

SUBSTANCE: invention relates to an aqueous dispersion (P) for preparing a coating composition, an aqueous coating composition, a topcoat, and a method for at least partially coating a substrate. Said aqueous dispersion (P) is an aqueous dispersion of at least two polymer resins (P1) and (P2), which differ from each other. Polymer resin (P1) is a copolymer obtained by copolymerisation of ethylenically unsaturated monomers in the presence of at least one polyurethane resin having polymerisable carbon double bonds. Ethylenically unsaturated monomers are selected from aliphatic or cycloaliphatic (meth)acrylates, (meth)acrylates bearing at least one hydroxyl group, (meth)acrylic acids, and mixtures thereof. Polymer resin (P2) is a polyester having functional hydroxyl groups and an acid number of less than 25 mg KOH/g polyester. Dispersion (P) is obtained by a method comprising (1) obtaining a dispersion or solution of at least one polymer resin (P1) in at least one organic solvent, (2) obtaining a mixture of a dispersion or solution obtained in step (1) and a melt or solution of at least one polymer resin (P2), (3) adding water to the mixture obtained in step (2), and (4) removing the organic solvent from the mixture obtained in step (3) to obtain aqueous dispersion (P).

EFFECT: resulting aqueous dispersion provides a liquid coating composition that is suitable for producing a topcoat by coil coating method, exhibits improved corrosion protection performance, is more environmentally friendly, suitable for preventing surface defects such as boiling marks, and also coatings obtained with its use do not have any disadvantages regarding the penetration of UV radiation and/or exposure to high or very low temperatures and are not easily separated from the underlying primer.

15 cl, 3 tbl, 3 ex