| 摘要 |
PROBLEM TO BE SOLVED: To provide an aqueous dispersion of a polyurethane resin which is excellent in film-forming property and provides a coating film having good heat resistance, weatherability and water resistance. SOLUTION: The aqueous dispersion of a polyurethane resin includes a polyurethane resin (U) having at least one of one or more kinds of polymerizable unsaturated groups selected from the group comprising (meth)acryloyl, (meth)allyl and 1-propenyl groups at its molecular side chain, and water. The aqueous dispersion satisfies all of the following (1) to (6): (1) the content of urethane group in (U) is 0.5-5.0 mmol/g based on the weight of (U); (2) the content of terminal amino group in (U) is≤0.35 mmol/g based on the weight of (U); (3) the number average molecular weight (Mn) of (U) is 10,000-1000,000; (4) The ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of (U), (Mw/Mn), is 1.5-3.5; (5) The melting temperature of (U) is 40-280°C; and (6) the volume average particle diameter (Dv) of (U) is 0.01-1μm. COPYRIGHT: (C)2011,JPO&INPIT
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