The Preparation Of Waterborne Polyurethane/epoxy Resin Composite Anticorrosive Coatings

In recent years,people have been paying more attention to environmental protection,making waterborne coatings gradually occupy the main market.However,whether it is domestic or abroad,the comprehensive properties of waterborne coatings for metal corrosion protection are not very satisfactory,which greatly reduces its application field.In order to solve the above problems,the crosslinking reaction between waterborne polyurethane and epoxy resin was used to enhance the densification of the system and achieve the complementation of the properties of the two resins.In order to further enhance the comprehensive characteristics of the composite system,silane coupling agent was used in the experiment.There is a very obvious repulsive between the ions with the same electrical properties,so the positive and negative charges in the electric double layer material can play an important role in blocking the diffusion of corrosive anions and cations,thus the addition of the electric double layer material to the coating can enhance the anticorrosion properties.In the experiment,montmorillonite was used as substrate and modified by salt solution to prepare the electric double layer material.The main contents of the paper are as follows:?1?The optimum ratio of waterborne polyurethane/epoxy resin was determined by orthogonal experiment,and the effects of the silane coupling agent's types,addition order,dosage and reaction time on the properties of the composite resin were investigated.The study showed that the crosslinking reaction of waterborne polyurethane and waterborne epoxy resin with mass ratio of 4:6 was carried out for 2 h,then KH550,which contained 2.5%of the solid content of the composite resin,was added to the mixture,and after 100 min,the waterborne polyurethane/epoxy resin composite matrix could be made.?2?The electric double layer material was prepared by modifying the montmorillonite substrate with ZnCl₂ solution,and the effects of various factors on the synthesis of the electric double layer material were investigated.The results of XRD and SEM showed that the best preparation conditions were as follows:the additive amount of ZnCl₂ solution with mass fraction of 10%was 29.4 mL,the addition rate was controlled at 1 mL/min,and the synthesized electric double layer material needed to be dried.?3?The waterborne polyurethane/epoxy composite coatings were prepared by adding the electric double layer material,mica ferric oxide and sericite as fillers into the waterborne polyurethane/epoxy resin composite matrix.Through the test results of comprehensive characteristics and anticorrosion characteristics,it was found that the solid elelctric double layer material,which accounts for 3%of the solid content of the composite matrix,was dispersed in an appropriate amount of deionized water,and added to the composite resin matrix at the rate of 1 mL/min.Then the mica ferric oxide and sericite,which both accounted for 10%of the solid content of the composite base,were added,and the mixture was stirred until it was completely dispersed,thus the waterborne polyurethane/epoxy composite coating with superior performance was obtained.