| The cured epoxy resin coating has good heat resistance,adhesion,electrical insulation and corrosion resistance.Epoxy resins are insoluble in water,so the early epoxy resin coating system was mainly solvent-based epoxy resin coating.The extensive use of organic solvents not only caused serious pollution problems,but also threatened the health of employees.With the development of society and the enhancement of people's awareness of environmental protection,solvent-based epoxy resin coatings have been gradually replaced by water-based epoxy resin coatings.Waterborne epoxy resin emulsion is an important part of the preparation of twocomponent waterborne epoxy resin coatings.Therefore,the preparation of waterborne epoxy resin emulsions with excellent performance has high economic value and practical significance.In this paper,polyethylene glycol,succinic anhydride,and epoxy resin are used as raw materials,and tetrabutylammonium bromide is used as a catalyst to synthesize a reactive epoxy resin emulsifier,and then the waterborne epoxy resin emulsion is prepared by the reverse conversion method;Branch reaction,modify epoxy resin with silane coupling agent and form modified water-based epoxy resin emulsion with selfmade water-based epoxy resin emulsifier;study the curing performance of the emulsion and amine curing agent crosslinking to form a film.The main research contents and conclusions are as follows:(1)Initially explore the influence of the choice of epoxy resin,polyethylene glycol and catalyst on the performance of the emulsion through preliminary experiments,so as to initially establish the experimental plan.(2)On the basis of preliminary experiments,continue to carry out single-factor experiments to determine the best choice of epoxy resin and polyethylene glycol,emulsifier structure,reaction temperature,catalyst dosage,emulsifier dosage and cosolvent dosage and other conditions.The emulsifier and emulsion were tested and characterized by Fourier infrared spectrometer,laser particle size analyzer and other instruments.The results show that when polyethylene glycol 8000 and epoxy resins E-20 and E-06 are selected as the raw materials for the synthesis of reactive epoxy resin emulsifier,and the molar ratio of epoxy resin to polyethylene glycol is 2: 1 The prepared emulsifier has the best emulsification effect;when the amount of the emulsifier is 22.4%,the co-solvent propylene glycol methyl ether: n-butanol = 1: 1,the amount is 22%,and the epoxy resin is emulsified in this proportion to obtain the waterbased ring The average particle size of the oxygen resin emulsion is 442 nm,the salt spray resistance time is 240 h,the mechanical stability test is not delaminated by centrifugation at 3000 r / min for 30 min,and it is not delaminated after being stored at room temperature for four months.(3)Using a silane coupling agent to modify an epoxy resin to prepare an aqueous epoxy resin emulsion through a graft reaction.Through single factor experiment,the effects of the types and dosage of silane coupling agent on the properties of emulsion and coating film were discussed.The experimental results show that at 110 ?,the amount of initiator BPO is 0.8%,when using 10% silane coupling agent A-172 modified epoxy resin,the particle size of the obtained emulsion can reach 257 nm,the coating film is salt-resistant Fog duration can reach 360 h.(4)The performance test of the coating film prepared by the reaction of the waterborne epoxy resin emulsion obtained in(3)with the amine curing agent was carried out.Influence of coating film performance.The experimental results obtained are as follows: when J-040 is used,the active hydrogen equivalent: epoxy equivalent = 1: 1,and the coating film prepared at the curing time of 30 min has the best performance,of which the coating film hardness is 2H,adhesion is 0,and resistance The length of the salt fog can reach 360 h. |
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