CATIONIC, ADVANCED EPOXY RESIN COMPOSITIONS

摘要

An advanced epoxy cationic resin having a charge density of from 0.2 to 0.6 milliequivalent of cationic charge per gram of resin is prepared by reacting in the presence of a suitable catalyst (A) a composition comprising (1) at least one diglycidyl ether of a polyol 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). Components (A) and (B) are employed in such quantities that the resultant epoxy resin has an average epoxide equivalent weight of from 350 to 10,000. The terminal oxirane groups in 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. Process for the preparation of these advanced epoxy cationic resins is also disclosed. Advanced epoxy cationic resin of this invention are employed in the preparation of coating compositions suitable for electrodeposition.