Preparations And Properties Of Aqueous Emulsion Of Self-Emulsified Epoxy Resins

The waterborne epoxy resin can be prepared and used with very little or without volatile organic compounds (VOC), therefore, it is environment-friendly and very attractive in many application fields. In recent years, much more attention has been paid to preparation and application of the waterborne epoxy resins.In this paper, modified epoxy resin which contains both unsaturated and hydrophilic groups was synthesized. Firstly, the epoxide acrylate with pendant hydroxyl groups was synthesized by using bisphenol A epoxy resin and acrylic acid as reactants and the complex prepared by the reaction of acetylacetone and chromium(III) chloride as catalyst. Secondly, the prepared epoxide acrylate was modified by maleic anhydride, which can be reacted with the pendant hydroxyl groups of the epoxide acrylate. Finally, the modified epoxide acrylate was neutralized by alkali, and dispersed in water to form very stable waterborne epoxy resin dispersion. The effects of the catalyst, reaction temperature and reaction time were studied. The optimum conditions of the synthetic reactions were determined. The reactive product was characterized by FITR.In the study of the preparation of the waterborne resin, the effects of the amine types, neutralizing temperature, hydrophilic group concentration and solid content on the properties of the dispersion were considered. The results suggested that the dispersability and stability of the emulsion would be improved with increasing the hydrophilic group concentration, neutralization degree and resin content. The photoinitiator Irgacure 1700 was preferred which had high initation efficiency and had excellent compatibility with the prepolymer. The curing rate is the suitable when the photoinitiator dosage is 4.0% (wt); the appropriate amount of the active monomer added improve not only the curing rate, but also the film performance. The water absorbance of the film will be increased with increasing the carboxyl group concentration. The film can be anti-yellow in 2 months if AMP-95 was served as the neutralization agent.