| 摘要 |
To provide a water-based coating composition capable of obtaining a coating film having excellent appearance and adhesion to an object to be coated without carrying out preliminary heating following the formation of a first base coating film in a method for forming a multilayer coating film by a 3C1B method. A water-based coating composition containing, as a base resin, a core/shell type emulsion resin comprising an acrylic resin as the core portion and a polyurethane resin as the shell portion, wherein the mass ratio of the core portion and the shell portion in the aforementioned core/shell type emulsion resin is between 20/80 and 80/20, the aforementioned acrylic resin has a hydroxyl group value of 40 to 140 mg KOH/g and an acid value of 0 to 10 mg KOH/g, the aforementioned polyurethane resin has a hydroxyl group value of 20 to 80 mg KOH/g and an acid value of 10 to 60 mg KOH/g, and the total mass ratio of constituent units derived from dibasic acids and/or dihydric alcohols having 10 to 60 carbon atoms in the aforementioned polyurethane resin is 10 to 50 mass % relative to the solid resin content of the aforementioned polyurethane resin. |
