| Epoxy resin is widely used in various complex fields such as adhesives,special composite materials,and functional coatings due to its excellent heat resistance,chemical resistance and electrical insulation.Among them,the water-based epoxy coating has the advantages of being green and environmentally friendly and easy to construct,and its film shrinkage rate is low,the hardness is high,and the wear resistance is good,which is unmatched by other water-based coatings.In modern industrial production,the reverse conversion method to prepare waterborne epoxy emulsion is widely used because of its simple operation,low cost,small emulsion particle size and high stability.Among them,the type of emulsifier will directly affect the performance of the waterborne epoxy emulsion,thereby further affecting the hardness,adhesion,and corrosion resistance of the coating.Therefore,the preparation of an epoxy resin emulsifier with high performance is the key to reverse conversion technology.In this paper,starting from the emulsified structure of non-ionic emulsifiers,three types of emulsifiers are synthesized with different types of epoxy resins as lipophilic groups and different types of polyether groups as hydrophilic groups.The respective optimal experimental technology and applicable emulsification conditions are determined.Finally,the epoxy emulsion and curing agent are formulated into non-ionic waterborne epoxy anticorrosive coatings,the anticorrosive properties of the paint films were compared.The main contents are as follows:（1）Polyethylene glycol and epoxy resin are reacted at a molar ratio of 1:1 to generate an AB type emulsifier with one end hydrophilic group and one end lipophilic group.The experimental conditions of emulsifier synthesis were determined by measuring the change of the epoxy value of the system during the reaction.The emulsifier and emulsion were tested and characterized by infrared spectroscopy and laser particle size detection,and the influence of emulsification conditions such as the amount of emulsifier,the temperature of the inversion,and the amount of hydrophilic monomer introduced in the inversion process were explored.When the temperature is60oC,the amount of emulsifier is 25%,the hydrophilic base is PEG4000 and the lipophilic base is E-51,the emulsion prepared with moderate viscosity,average particle size of 436nm,high stability and good overall performance.（2）Polyethylene glycol and epoxy resin are reacted at a molar ratio of 1:2 to produce a triblock type ABA emulsifier with a hydrophilic segment in the middle and lipophilic groups at both ends.The reaction time of the experiment was determined by the determination of the epoxy value during the reaction.The emulsifier and emulsion were tested and characterized by infrared spectroscopy and laser particle size detection,and the influence of emulsification conditions such as the amount of emulsifier,the temperature of the inversion,and the amount of hydrophilic monomer introduced in the inversion process were explored.When the temperature is 65oC,the amount of emulsifier is 17%,the hydrophilic base is PEG4000 and the lipophilic base is E-51,the emulsion prepared with moderate viscosity,average particle size of372nm,high stability and good overall performance.（3）Polyetheramine reacts with epoxy resin in a molar ratio of 1:2 to produce an emulsified structure of A2B type emulsifier with two lipophilic groups as the branched backbone and hydrophilic polyether structure segments.By testing the particle size and stability of the emulsion prepared by the emulsifier under different processes,it is found that the emulsifier prepared under the experimental process of adding polyetheramine to the epoxy resin at 70°C has a sufficient reaction and the stability of the emulsion is relatively high.The emulsifier and emulsion were tested and characterized by infrared spectroscopy and laser particle size detection,and the influence of emulsification conditions such as the amount of emulsifier,the temperature of the inversion,and the amount of hydrophilic monomer introduced in the inversion process were explored.When the temperature is 40oC,the amount of emulsifier is 16%,and the hydrophilic group adopts polyetheramine M2070 and the lipophilic group adopts E-20,the emulsion prepared with moderate viscosity,average particle size of 283nm,high stability and good overall performance.（4）The waterborne epoxy emulsion prepared under different emulsifiers and self-made curing agent are made into non-ionic waterborne epoxy anticorrosive paint,and the anticorrosive performance of the paint film is tested.According to the comparison between conventional corrosion test and electrochemical polarization curve analysis,the emulsion prepared with ABA emulsifier has the most sufficient curing reaction and the best anti-corrosion performance of the paint film.Its surface drying time is 40min,hardness 2H-3H,and adhesion level 0,The impact resistance can reach 50cm,and the overall performance of the paint film is excellent. |
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