| Traditional solvent-based epoxy resin coatings has good propertise such as corrosion resistance, but ti will evaporate a lot of volatile organic compounds(VOC)in the process of preparation and use, which may affect the environment severely.Waterborne epoxy resin emulsion, which can achieve the environmentally friendly requirement, not only holds the excellent performance of solventborne solvent-based epoxy resin but also reduce the amount of VOC,so it has been the research hotspot.Three parts are mainly studied in this paper.The first one was the preparation of waterborne epoxy resin emulsion. The intermediate product with two terminal carboxyl groups, which was produced by esterification reaction between succinic anhydride and polyethylene glycol, was used to produce the water-borne epoxy resin emulsifier by the ring-opening reaction with epoxy resin. And the modified epoxy resin had the function of emulsifying. So the waterborne epoxy resin emulsion could be obtained through phase reversion with the modified epoxy resin. The lower viscosity aqueous dispersion with high solid content and smaller size, has better properties such as corrosion resistance and higher hardness properties,and so on, which can be widely used in anti-corrosion primer metal substrate.This paper mainly studied on the molecular weight of the PEG during the preparation of the emulsifier. At the same time, the content of emulsifier, the types and amount of cosolvents and the reaction temperature were also investigated in the emulsification process. Through the continuous experimental exploration, it indicates that the function of the waterborne epoxy emulsifier can be better when the molecular weigh of PEG is 8000, the content of the emulsifier is 20%, the content of propylene glycol monomethyl ether is 15% and the emulsifying temperature is 70℃.The second one was the preparation of waterborne epoxy curing agent. The polyamine was modified by the compound of neopentyl glycol diglycidyl ethe and epoxy resin E-44. The faint yellow waterborne epoxy curing agent, which had a good compatibility with waterborne epoxy resin, could be obtained after the adding of the capping agent and the deionized water in the modified polyamine.In this process, it was mainly studied on the types of polyamine, the molar ratio of the raw materials, the amount of neopentyl glycol diglycidyl ethe, the types of capping agent, capping rate and the reaction temperature ect. The result shows that the property of the modified agent is better when the tatio of all raw materials is tyiethylene tetramine(TETA): neopentyl glycol diglycidyl ethe:epoxy resin E-44:benzyl glycidyl ether =2.1:0.5:1.8, the best reaction temperature is 70℃ and the capping rate is 90%. The agent pruduced in this way, whose pot life could be 3hours,has good properties such as good salt water resistance, adhesion and impact resistance.The last one was the preparation of waterborne epoxy resin varnish and films by self–made waterborne epoxy resin emulsion, waterborne epoxy resin curing agent,consumers foaming agent(BYK-028) and wetting dispersant(TEGO-270). The film was obtained by scratching the varnish on the cleaned tinplate using a bar. Through constantly optimizing formulations of formulations and a series of performance test,the main conclusion are as follows: the film has good properties when the solid content is 40%, the molar ratio of reactive hydrogen and epoxy group is 0.9:1 and the amount of water wetting dispersant and consumers foaming agent are both 0.1%. |
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