Preparation And Properties Of Self-Emulsified Water-Borne Epoxy Resin

Epoxy resin is one kind of thermosetting resins with stable molecularstructure, it has been used in a widely flied. Epoxy resin mostly is solid or highviscosity liquid. The molecular structure of epoxy resin has some polar groups,but the non-polar in main chain of molecules lead to epoxy resin dissolved inorganic solvents, such as alcohols and ketones, instead of water. Most of theorganic solvents are toxic, volatile, flammable and explosive, have greatenvironmental pollution. So the preparation of non-toxic, tastelessness andunpolluted water-borne epoxy resin has become research emphasis.In this paper, bisphenol-A epoxy resin, toluene diisocyanate and2,2-dimethylol propionic acid were used in preparing water-borne epoxy resin.Hydroxy and carboxyl were introduced in main chain of molecules of epoxy resinby self-emulsified, then N,N-dimethylethanolamine was used in salt forming byneutralization. Under stirring, water-borne epoxy resin emulsion was prepared bydropping water into the mixed solution. The experience showed that water-borneepoxy resin emulsion had good stability and water dispersive. In this experiment,the influences of material ratio, reaction time and reaction temperature onreaction were studied, and the optimal reaction process was determined byorthogonal experiment analysis. The optimal reaction was obtained as follows:n(E-44):n(TDI):n(DMPA)was1:0.5:0.5, the reaction temperature was60℃and thereaction time was3hours. The structures of products were tested by infraredspectrum. The particle size distribution, water-soluble, stability and viscosity ofwater-borne epoxy resin emulsion were tested. The results showed that water-borne epoxy resin dispersed and distributed well in water, the average diameterwas230nm. Under stirring, added water in modified epoxy, modified epoxy resinhad good stability and water dispersive when the volume ratio of water andmodified epoxy resin smaller than3:1. When the volume ratio of that larger than 3:1, modified epoxy resin still dispersed well in water, but the stability showed asharp decline trend.