| 摘要 |
<p>An aqueous polyurethane resin dispersion which can provide a coating film having high impact resistance and hardness and excellent in adhesiveness to an electrodeposited coating surface is to be provided. It is an aqueous polyurethane resin dispersion which comprises a polyurethane resin obtained by reacting (A) a polyurethane prepolymer which is obtained by reacting (a) a polyisocyanate compound, (b) at least one polyol compound containing a polycarbonate polyol having a number average molecular weight of 400 to 3000, (c) an acidic group-containing polyol compound, and (d) a blocking agent for an isocyanate group, which dissociates at 80 to 180°C, and (B) a chain elongating agent which has reactivity with the isocyanate group, being dispersed in an aqueous medium, a sum of a content of urethane bodings and a content of urea bondings is 15 to 30% by weight in terms of solid components, a content of carbonate bondings is 8% by weight or more and less than 15% by weight in terms of solid components, and a content of an isocyanate group to which the above-mentioned blocking agent has bound is 0.2 to 3% by weight in terms of solid components and calculated on the isocyanate group.</p> |
