| 摘要 |
<p>An aqueous polyurethane resin dispersion exhibits excellent drying properties of coating films and gives coating films having high water resistance and on the other hand showing a high rate of swelling with respect to aqueous cleaning liquids to permit new application. The aqueous polyurethane resin dispersion is a dispersion of a polyurethane resin in an aqueous medium, the polyurethane resin being obtained by reacting (A) a polyurethane prepolymer obtained from (a) a polyisocyanate compound, (b) a polycarbonate polyol with a number average molecular weight of 400 to 3000, (c) an acidic group-containing polyol compound and (d) a blocking agent, with (B) a chain extender, the total content of urethane bonds and urea bonds being 7 to 15 wt%, the content of carbonate bonds being 15 to 40 wt%, the content of ether bonds being 0 wt%, the content of isocyanate groups bonded to the blocking agent being 0.2 to 2 wt%, each of these contents being based on solid contents, the acid value being 11 to 16 mg KOH/g, the weight average molecular weight being 25,000 to 60,000. A coating composition includes the dispersion. A polyurethane resin film is obtained by thermally drying a composition including the dispersion.</p> |
