Self-crosslinking cationic polyurethane based electrodepositable binders

摘要

Binders for cathodically depositable aqueous coating compositions comprising the reaction product of (A) one mole polyisocyanate with (B) at least one mole dialkylalkanolamine and a monohydroxyalkyl(meth)acrylate and/or monohydroxyalkoxy(meth)acrylate and/or a monohydroxyallylether of a polyol. Optionally, there can be included a saturated and/or unsaturated fatty alcohol or fatty acid. The binders have an NCO-value of substantially zero; a molecular weight of from about 500 to 5000, and in each 1000 molecular weight unit a basic content of from about 0.5 to 3 and a double bond content of from about 0.5 to 4. The binders in coating compositions cure at relatively low temperatures and relatively short curing times to provide films having excellent resistance to water, chemicals, and corrosion.