POLYURETHANE RESIN AQUEOUS DISPERSION

PROBLEM TO BE SOLVED: To provide a polyurethane resin aqueous dispersion capable of providing a coating film excellent in all of weather resistance, heat resistance, hydrolysis resistance, flexibility and impact resilience.SOLUTION: A polyurethane resin aqueous dispersion (U) according to one embodiment is provided that contains: a polyurethane resin (P) which has an oxycarbonyl group and a carbonate group as ester groups and in which total value of urethane group concentration and urea group concentration is 7.0 to 11.0 wt.%; and an aqueous medium. A polyurethane resin aqueous dispersion (U) according to another embodiment is provided in which the polyurethane resin aqueous dispersion (U) according to the one embodiment satisfies that: the (P) is obtained by reacting an active hydrogen component (A) containing polyester polyol having the oxycarbonyl group and the carbonate group as ester groups and having a number average molecular weight of 500 or more (a113) and a compound having a hydrophilic group and active hydrogen (a2) and an organic polyisocyanate component (B); storage elastic modulus E' and tanδ of the coating film obtained by drying the (U) at 20°C are 1 to 70 MPa and 0.05 to 0.30, respectively; and thermal softening point of the coating film obtained by drying the (U) is 200 to 300°C.SELECTED DRAWING: None 【課題】 耐候性、耐熱性、耐加水分解性、柔軟性及び反発弾性のいずれにも優れる皮膜が得られるポリウレタン樹脂水性分散体を提供する。【解決手段】エステル基としてオキシカルボニル基とカーボネート基を有し、ウレタン基濃度とウレア基含濃度の合計値が７．０〜１１．０重量％であるポリウレタン樹脂（Ｐ）及び水性媒体を含有するポリウレタン樹脂水性分散体（Ｕ）。前記（Ｐ）が、エステル基としてオキシカルボニル基とカーボネート基とを有する数平均分子量が５００以上のポリエステルポリオール（ａ１１３）及び親水性基と活性水素を有する化合物（ａ２）を含む活性水素成分（Ａ）と有機ポリイソシアネート成分（Ｂ）とを反応させて得られ、前記（Ｕ）を乾燥させた皮膜の２０℃における貯蔵弾性率Ｅ'が１〜７０ＭＰａ、かつ、ｔａｎδが０．０５〜０．３０であり、前記（Ｕ）を乾燥させた皮膜の熱軟化点が２００〜３００℃である。【選択図】 なし