Cathodic electrodepositable coating compositions comprising an aqueous dispersion of (1) at least one cationic epoxy-based resin, (2) at least one blocked isocyanate crosslinker, and (3) a solvent system containing one or more organic solvents are improved by (a) employing a blocked isocyanate crosslinker which deblocks at a temperature of less than 160°C, and (b) employing as the solvent system, one which is substantially free of any organic solvent which will react with isocyanate groups at the temperature employed to cure said coating.
阴极电沉积涂料组合物包含(1)至少一种阳离子环氧基
树脂,(2)至少一种封端
异氰酸酯交联剂,和(3)含有一种或多种有机溶剂的溶剂体系的
水性分散体,该组合物通过以下方法得到改进:(a)采用在低于 160°C 的温度下解锁的封端
异氰酸酯交联剂,和(b)采用基本上不含在固化所述涂层的温度下会与
异氰酸酯基团发生反应的任何有机溶剂的溶剂体系、(b) 采用基本上不含任何有机溶剂的溶剂体系作为溶剂体系,这种溶剂体系在固化所述涂层的温度下会与
异氰酸酯基团发生反应。