| 摘要 |
PROBLEM TO BE SOLVED: To provide a water-based blocked polyisocyanate composition having low-temperature curing properties, being a curing agent providing a coated film of a urethane coating material, having good film properties such as impact resistance and weather resistance, and obtained by covering a carboxy group into a hydrophilic group. SOLUTION: This water-based blocked polyisocyanate is obtained by using a polyisocyanate derived from a precursor derived from an aliphatic or alicyclic diisocyanate, and satisfying the following all conditions (a), and satisfies the following all conditions (b): conditions (a): 1. having 4.5-20 average number of isocyanato groups; 2. having 3,000-100,000 mPa.s viscosity at 25 deg.C; 3. having 1,000-50,000 number average molecular weight; and 4.2-23 wt.% concentration of the isocyanato group; and conditions (b): 1. containing a blocked isocyanato group and a carboxy group in one molecule; 2. having 10-100 mgKOH/g acid value per resin; 3. having 3.5-19 average number of the blocked isocyanato groups; and 4. having 1.8-20 wt.% concentration of the blocked isocyanato groups. |
