| 摘要 |
PROBLEM TO BE SOLVED: To obtain a coating composition excellent in cissing resistance and edge corrosion resistance and can give an electrodeposition coating film having appearance and performances not adversely affected by the constituent cissing inhibitor or edge corrosion inhibitor by using a polyurethane obtained from a diol having a specified molecular weight as the cissing inhibitor or the edge corrosion inhibitor. SOLUTION: The polyurethane used is obtained by reacting an isocyanate with a diol having a number-average molecular weight of 300-3,000 and selected from among a polyalkylenepolycarbonatediol represented by formula I, wherein n is 2-8; and w is 1-12, a bisphenol A/ethylene oxide adduct represented by formula II, wherein each x is 1-10, a polyesterdiol represented by formula III, wherein R1 and R2 are each independently a 1-18C alkylene; and y is 1-10, and an alkylenediol/lactone adduct represented by formula IV, wherein R3 is a 2-15C alkylene; m and n are each 2-10; and each z is 1-25. It has a weight- average molecular weight of 30,000-300,000 and is used singly or in the form of a mixture of at least two such resins.
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