The Research On Preparation And Performance Of Curing Agents For Waterborne Epoxy Resin

Two-component ambient-cured waterborne epoxy coatings system is one possible approach to replace solvent borne epoxy/polyamide. In this paper the emphasis are laid on the studies of preparation and performance of curing agents for two-component ambient-cured waterborne epoxy coatings.First, a new water-soluble curing agent with excellent cure property has been developed through modifying a amidoamine curing agent. The epichlorohydrin are chosen for the chain extender in preparation of that curing agent. The parameters of process, including reaction temperature, reaction time, mole ratio of reaction materials have been determined. The reactive result has been characterized by FTIR and other methods. The type of polyamine influence on the property of curing agents has been discussed in detail. The crosslinking behavior of waterborne epoxy coating film cured by various curing agents has been studied by thermo analysis in the same time. Result shows that a good curing agent with proper reactivity, low Tg and good compatibility with epoxy resin is the key to good film performance.Second, studies on the anti-corrosion and anti-water property of dry film of type II system have been carried out by EIS method and compared with their solvent borne counterparts simultaneously. The reason for their poor corrosion resistance property has been discussed through the research on their curing mechanism. The result also has been approved by SEM test. Dry film performance studies on the ratio of epoxy equivalent to amine hydrogen equivalent has been carried out as well as the using of coalescing solventsLast, the attempts to synthesize a curing agent emulsion has been done. Two ways has been tried to getting curing agent emulsion with good dispersion stability, that is:l)modifying the water-soluble curing agent by reacting with hydrophobic end-capped agents.2)more hydrophobic E-51 epoxy resin used as extender in preparation. Results show that none of it can reach the aim and a rational explain has given. Another two routes for synthesizing curing agents emulsion has been raised.