Abstract: The object of the present invention is to provide an aqueous coating composition which exhibits a small viscosity change and can form a coating film having a superior coating film appearance even when the amount of the solvent contained in the aqueous coating composition is reduced due to changes in the coating environment.

Abstract: The present invention provides an aqueous coating composition that exhibits a small change in viscosity and can form a coating film having a superior coating film appearance even when the amount of a solvent contained in the aqueous coating composition decreases due to the change of the coating environment. An aqueous coating composition containing a polyester resin dispersion (A) and a melamine resin (B), wherein the polyester resin constituting the polyester resin dispersion (A) contains an alkyd resin having an acrylic vinyl-based polymer segment; the melamine resin (B) contains a hydrophobic melamine resin; as to a viscosity of a dry coating film of the coating composition, a coating film viscosity ?1 of a dry coating film whose solid content is 60% by mass and a coating film viscosity ?2 of a dry coating film whose solid content is 80% by mass satisfy the following condition: 1??2/?1?10, where the coating film viscosities ?1 and ?2 are viscosities measured at a temperature of 25° C.

Abstract: An object of the present invention is to provide an aqueous coating composition that exhibits a small change in viscosity and can form a coating film having a superior coating film appearance even when the amount of a solvent contained in the aqueous coating composition decreases due to the change of the coating environment. The present invention provides an aqueous coating composition containing a polyurethane resin dispersion (A) and a melamine resin (B), wherein the melamine resin (B) contains a hydrophobic melamine resin, and the polyurethane resin constituting the polyurethane resin dispersion (A) has a viscosity in a range of 101 to 150,000 Pa·s measured at a temperature of 25° C. and a shear rate of 0.1 sec?1.

Abstract: An aqueous coating composition comprising an acrylic resin dispersion (A) having a core/shell structure and a melamine resin (B) comprising a hydrophobic melamine resin, wherein the acrylic resin dispersion (A) is a dispersion of a solution-polymerization product of a core part preparation monomer (a-1) and a shell part preparation monomer (a-2), wherein the shell part preparation monomer (a-2) comprises an acid group-containing polymerizable monomer. The aqueous coating composition exhibits a small viscosity change and can form a coating film having a superior coating film appearance, even when the amount of the solvent contained in the aqueous coating composition is reduced due to changes in the coating environment.