WATER-BASED POLYURETHANE RESIN COMPOSITION, COATING MATERIAL USING SAID COMPOSITION, AND COATED ARTICLE

摘要

This water-based polyurethane resin composition is obtained by dispersing, in water by using an anionic group neutralizer (D), a terminal isocyanate group-containing urethane prepolymer obtained by reacting polyol (A), isocyanate (B), and an anionic group-introducing polyol (C) containing a carboxyl group or a sulfonic acid group, and by subjecting the terminal isocyanate group-containing urethane prepolymer to elongation in water. The water-based polyurethane resin composition being characterized in that the essential component of component (A) is a C10-32 long-chain alkylene diol compound (a), wherein the content of component (a) is 1 to 20 mass % in relation to the total amount of components (A), (B) and (C), and the equivalent ratio of the isocyanate group (NCO) in component (B) relative to the total hydroxyl groups (OH) in component (A) and component (C) is 1.3 to 1.9 when NCO/OH. This water-based polyurethane resin composition exerts excellent water and chemical resistance, adhesion to a base material, and coating stability, and is particularly suitable as a coating material since the composition can be suitably used as a coating material for a surface-treated steel plate.