Cationic UV-Cured coatings containing epoxidized soybean oil initiated by new onium salts containing tetrakis(pentafluorophenyl)gallate anion

Different formulations containing epoxidized soybean oil (ESO) and a commercial cycloaliphatic epoxy resin (UVR6110) were cured by onium tetrakis(pentafluorophenyl)gallate (Gallate) on steel panels. The resulting coatings were clear and their mechanical properties were tested by the Sward hardness test, cross-hatch tape adhesion test and MEK double rub test. The new initiators have the advantage of good solubility, high reactivity, and the production of colorless coatings. The best formulations obtained contain 50% ESO, 50% UVR6110, and 0.5% silwet if sulfonium gallate is used as initiator, and 60% ESO, 40% UVR6110, and 0.5% silwet if iodonium gallate is the initiator.