Cationic, advanced epoxy resin compositions incorporating glycidyl ethers of oxyalkylated aromatic or cycloaliphatic diols

摘要

An advanced epoxy cationic resin useful as a cathodic electrodeposition coating is prepared by reacting in the presence of a suitable catalyst (A) a composition comprising (1) at least one diglycidyl ether of (a) an oxyalkylated aromatic diol or (b) an oxyalkylated cycloaliphatic diol or (c) certain oxyalkylated aliphatic diols and (2) at least one diglycidyl ether of a dihydric phenol with (B) at least one dihydric phenol and optionally (C) a monofunctional capping agent. Components (A-1) and (A-2) are employed in quantities such that from 10 to 75 weight percent of the diglycidyl ethers contained in component (A) are contributed by component (A-1), and from 25 to 90 weight percent of such glycidyl ethers are contributed by component (A-2). The terminal oxirane groups in the thus formed advanced epoxy resin are converted to cationic groups by reacting the resin with a nucleophilic compound and adding an organic acid and water at at least one point in the reaction.