| 摘要 |
PROBLEM TO BE SOLVED: To provide a powder coating composition which contains a curing agent which contains a uretoneimine bond, can be obtained by a simple and easy way, and when compounded into a powder coating material, exhibits a low weight loss on heating and an excellent low-temperature curability. SOLUTION: This powder coating composition contains a curing agent and a binder resin containing hydroxy and carboxy groups. The curing agent is prepared by converting an isocyanate compound into a carbodiimide and then into a uretoneimine to produce a polyisocyanate and blocking thus obtained polyisocyanate with an active hydrogen compound. The carbodiimidization is conducted so that the isocyanato group content of the isocyanate compound is decreased to 2/3 the initial content and so that the isocyanato group content of the polyisocyanate is 3.2-4.2 mmol/g.
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