Patent ID: 8859676

Claim:
An aqueous polyurethane resin dispersion which comprises a polyurethane resin obtained by reacting (A) a polyurethane prepolymer which is obtained by reacting (a) an alicyclic diisocyanate compound, (b) a polycarbonate polyol containing an aliphatic diol or alicyclic diol unit and 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 bondings and a content of urea bondings is 7 to 18% by weight in terms of solid components, a content of carbonate bondings is 18 to 35% by weight in terms of solid components, and a content of an isocyanate group to which the above-mentioned blocking agent has bonded is 0.2 to 3% by weight in terms of solid components and calculated on the isocyanate group, wherein (a) the alicyclic diisocyanate compound is at least one selected from the group consisting of isophorone diisocyanate and 4,4′-dicyclohexylmethane diisocyanate, (c) the acidic group-containing polyol compound is at least one selected from the group consisting of 2,2-dimethylol propionic acid and 2,2-dimethylol butanoic acid.