| With the need of economic development and the pressure of environmental protection,traditional two-component solvent-based epoxy coating is being replaced slowly by two-component waterborne epoxy coating.It is necessary for studying high-performance waterborne epoxy resin and their curing agent now.In this paper,the adduct was synthesized by the reaction of polyethylene glycol and epoxy resin E51,and then the polyetheramine was used to extend the adduct,which was used as an emulsifier.The epoxy resin E20 was emulsified by a reverse conversion method to prepare an waterborne epoxy emulsion.The emulsifier synthesized with PEG4000,epoxy resin E44 and polyether amine MZ600 was mainly used.The structure and molecular weight of the emulsifier were analyzed through infrared spectrum and determination of epoxy equivalen,the effects of different emulsifiers content on waterborne epoxy emulsion’s particle size and stability were studied,when emulsifier content was the same,the effects of different polyethylene glycol,different epoxy resin and different terminal polyether amine emulsifier on the particle size and stability of the dispersible emulsion were studied.The effect of shearing rate on particle size and stability of the epoxy emulsion were also studied.The emulsifier is prepared with polyethylene glycol PEG4000,epoxy resin E44 and polyether amine MZ600.When the emulsifier content is 12%,the average particle size of the epoxy emulsion is 346.0nm,and the stability of epoxy emulsion is good.Then,the modified epoxy resin was synthesized with dimer acid,bisphenol A and epoxy resin E51,and emulsified with the above-mentioned self-made emulsifier to obtain a modified water-based epoxy resin emulsion.Infrared spectroscopy was used to characterize the structure of the epoxy resin modified by dimer acid.The effect of different amounts of catalyst on the synthetic resin was studied.The effects of different dimer acid contents on the glass transition temperature of synthetic resin,particle size and viscosity of the emulsion were studied.The particle size of the waterborne epoxy modified epoxy resin emulsion decreases first and then increases with the increase of the dimer acid content.The most suitable dimer acid content is about 10%,and the particle size is 252.2nm.A certain proportion of polyethylene glycol and epoxy resin E51 were reacted to providehydrophilicity.The adduct was added dropwise to isophorone diamine sealed by butyl glycidyl ether to obtain non-ionic waterborne epoxy curing agent.The reaction process of the adduct was monitored by the determination of epoxy equivalen,The effects of molar ratio and epoxy equivalent of the reaction between epoxy resin and polyethylene glycol,the sealing rate of butyl glycidyl ether to isophorone diamine on the solubility and viscosity of the synthetic curing agent and the appearance of the cured paint film were studied.When the molar ratio of epoxy resin and polyethylene glycol was definite,the effect of reaction time on the epoxy equivalent of the adduct was investigated.The reaction molar ratio of epoxy resin E51 and polyethylene glycol PEG1000 is 4: 1,the temperature is 100 ℃,and reaction time is above 5hours.The resulting adduct is added dropwise to 20% isophorone amine end-capped with butyl glycidyl ether.A transparent yellow waterborne epoxy curing agent is obtained.Finally,the comprehensive performance of the film was texted.Epoxy emulsifier was prepared by the reaction of epoxy resin E44 with polyethylene glycol PEG4000 and polyether amine MZ600,which could emulsify epoxy resin E20 with different emulsifier content to prepare emulsion,and emulsify epoxy resin modified by dimer acid to prepare the emulsion in the meantime;the selected curing agent was prepared by epoxy resin E51 and polyethylene glycol PEG1000 with 20% isophorone amine end-capped with butyl glycidyl ether.The effect of different epoxy group and amine hydrogen ratios of the mixed waternorne epoxy emulsion and waterborne epoxy curing agent on the performance of varnish film was studied.The emulsion with different emulsifier contents and the toughened modified resin emulsion on the varnish film were investigated.At the same time,the thermal stability of the paint film after curing was tested by TG analysis. |
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