Waterborne Epoxy System And Curing Performance In Coating

With lab made emulsifier EM, three common used epoxy resins-liquid DGEBPA epoxy NPEL-128, solid DGEBPA epoxy NPES-901and liquid phenolic epoxy EPN-1138were emulsified. Through the testing on emulsification process and emulsion stability, finally the emulsifier dosage of20%show the better performance with average emulsion particle size less than5micron and good emulsion stability. The selected curing agents were made through adducting of aminoethylpiprazine and epoxy resin. The best reaction condition for the amine-epoxy adducting process were decided at60°C/2hrs through analysis on effects of different reaction temperature and time period. Four different amine-epoxy adducts were made with the change of mole ratio between amine and epoxy. Curing performance and coating properties were tested with the selected epoxy emulsions and curing agents. From the test results, epoxy resin type show majority effects on the film drying speed, high molecular weight epoxy NPES-901show the fastest drying speed, while the low molecular weight epoxy NPEL-128is the slowest. The panel properties will heavily depending on the compatibility between epoxy emulsion and curing agent, the better compatibility the better overall performance. And the amine-epoxy adduct, made from reaction of aminoethylpiprazine and phenolic epoxy EPN-1138at mole ratio1:0.11, show the best compatibility with all three epoxy emulsions and overall good panel properties.