Preparation And Properties Of Non Ionic Waterborne Polyurethane Modified Epoxy Resin Coatings

With the enhancement of people's awareness of environmental protection,the development of water-based resin has become the focus of people's research.Although waterborne epoxy resin has excellent performance,its use is limited by its poor impact resistance,while polyurethane chain segment is supple and has good wear resistance.Chemical modification method is used to combine the two with good flexibility to make up for the poor impact resistance of epoxy resin,and more excellent performance of resin can be obtained.At present,waterborne polyurethane modified epoxy resin is mainly anionic modified,but the emulsion epoxy prepared by this method has low group content,low solid content and poor curing film performance.This topic adopts non-ionic modification,the research content and conclusions are as follows.This topic in the new nonionic glycol(Ymer N120)for the preparation of nonionic hydrophilic chain extender waterborne polyurethane modified epoxy resin emulsion,emulsion is studied in the maximum content of epoxide group(expressed in epoxy value),the largest solid content of latex and nonionic glycol content of chain extender on the properties of the emulsion.The results show that the maximum content of epoxy group in the emulsion is 0.19,and the maximum solid content is 52.5%when the amount of nonionic diol is 4.8%.Nonionic waterborne epoxy resin curing agent was prepared by modifying diethylenetriamine with a variety of compounds containing epoxy groups,and the coating was mixed with modified epoxy resin emulsion.The effect of the ratio of active hydrogen to epoxy group on the properties of curing agent and coating was studied.The results show that when the content of PEGDDE is4%,the viscosity of curing agent is 4430 m Pa�s,and the curing agent has good dispersion in water.When the ratio of active hydrogen to epoxy group in modified hardener is 3/1,the corrosion potential is the highest(-0.464 V),the corrosion current density is the lowest(8.49�10^-8 m Acm^-2),the capacitive arc diameter is the largest,and the anticorrosion property is the best.The effect of the ratio of epoxy groups in the emulsion to active hydrogen in the curing agent was studied.The results show that when the ratio of epoxy group in emulsion to active hydrogen in curing agent is 1:1,the coating has the best water resistance and acid and alkali resistance.Electrochemical tests show that the corrosion resistance of the cured coating is the best at this ratio.