Crosslinkable composition comprising aminoepoxy resin.

Abstract

A substantially gel-free self-crosslinkable diene functional blocked dienophile functional aminoepoxy resin is prepd. by the reaction of a diepoxide with an amine functional diene chain extender, an amine functional blocked dienophile chain extender, a modifying agent comprising a hydroxy functional secondary amine, and, optionally, a monofunctional end-capping reactant. The resin is useful in solvent-based primer coatings, cathodic electrocoating compns., adhesives, etc. The coatings have good resistance to humidity and solvents. Thus, 166 g 3,6-endoxo-1,2,3,6-tetrahydrophthalic anhydride was added to 170 g isophoronediamine in 300 g MeOCH2CH2OMe to give an amino maleamic acid. A mixt. of this acid 32.70, a diepoxide (Epon 1001F) 339, Bu Cellosolve 100, furfurylamine 18.78, and diethanolamine 9.34 g was heated 2.5 h at 60-95° to give a resin. A mixt. of the resin 454, AcOH 10.21 (in 25 g H2O), and H2O 1575 g was prepd. and electrodeposited onto bare steel panels and conversion coated steel panels at 100-400 V without rupture. The coating was baked 30 min at 150-180°, giving a coating having 1 mm loss of adhesion from a scribe line in 72 h of salt spray testing (ASTM B117). [on SciFinder(R)]