Synthesis And Properties Of Waterborne Anti-corrosive Transformed Emulsion

The waterborne anti-corrosive transformed coating was also called the rust on the surface coating,rust paint,not to rust coating,just as its name implies it was a new type of coatings on metal substrates can be directly coated on the residual rust of the metal substrate surface,used for protection of metal primer.It can be painted on the surface of the rusty metal substrate,anti-corrosive coating,without the need for very thorough corrosion of rust metal,which has to reduce the cost of pre-treatment,reduced labor intensity,protected the environment and human health and other advantages,conversion coating has a good application of broad market prospects.Rust conversion agent of the conversion coatings can interact with the rust,formed stable chelate configuration of hexatomic ring,could be adhered to the substrate surface,transformed the rust stability,played an important role in reaching anti-rust and protecting the metal.It is common that there are many traditional rust conversion agents,for instance phosphoric tannins acid,phosphoric organic acid or inorganic acid,However,these rust conversion agents also have many problems at the same time,such as the effects of tannic acid type and concentration,and the influence of the concentration of phosphate,which are easily affected by the transformation of rust.Concentration,phosphoric acid concentration and other effects,and the corrosion situation of steel,also have a greater relationship.Such as tannic acid high molecular weight,complex structure,the concentration of phosphate is not well controlled.Phosphoric acid is in strong acid,strong acidity,it can easily transformed conversion residue after,and then continued to etch the metal internal substrate,impacted the long-term corrosion result.Besides,corrosion of metal substrate is influenced by many factors,In certain ways of single corrosion,the existence of uneven surface,the different of thickness no testable concrete standard and so on.there is no specific standards to test and illustrate other issues.From the point of view of high energy,high efficiency and environmental protection,this work polyphenolic compounds have been used to replace the traditional rust-transfer system,to overcome the problems such as the corrosionresistance to metal substrate is not obvious,over-eroding or smearing uneven.As complexing agent,gallic acid can which is able to coordinate with iron ion to form stable complexes,is used as a rust inhibitor.It is compatible with small molecular substances to react,to get a new type of rust conversion agent.The complexing agents were prepared by reacting gallic acid with maleic anhydride and 1,2-propanediol etc.respectively.The properties of the different rust inhibitors were analyzed and represented,and the individual physicochemical properties were compared respectively.The phosphate functional monomer with anti-erodibility was prepared by using P2O5 as the phosphating reagent and bifunctional hydroxyethyl acrylate to improve the properties of the emulsion and improve the adhesion of the emulsion coating and the gloss of the coating.Adopting the pre-emulsification continuous emulsion polymerization method,the functional phosphate monomer,methyl methacrylate,butyl acrylate and other acrylic monomers were involved in the emulsion polymerization,coupled with the rust conversion agent,copolymerization preparation of waterborne anti-corrosion turn rust emulsion,making the emulsion anti-corrosion performance upgrade.The structures of the reactants were characterized by FT-IR,XPS and XRD.The thermal stability was measured by DSC.SEM + EDX was used to measure the micro structure and the types and contents of coating elements.The electrochemical properties of the coatings were investigated by electrochemical measurements with different p H and different immersion times.The physical and chemical properties of the emulsion were tested to determine the film-forming and anti-corrosion properties of the emulsion coating.The stability of the test emulsion was analyzed by Turbiscan lab stability analyzer.The particle size and particle size distribution index of the emulsion was analyzed by nano-particle size surface potential analyzer.The adhesion of the coating,the hardness of the coating,the water resistance and salt spray resistance of the coating were analyzed.The results showed that the viscosity of the rust inhibitor Ⅲ was the highest,followed by the rust inhibitor Ⅱ,the viscosity of the rust inhibitor Ⅰwas the lowest,the coating adhesion was good,The rusting effect is obvious,the coating will be black,but the drying time is slightly different,in which the rust agent Ⅱ and the rust agent Ⅰ surface drying and actual drying time is short,thetransfer of rust agent coated rusty steel,Rust thoroughly,evenly,the phenomenon and the effect is obvious.The results showed that the emulsion viscosity,solid content and gel content had no significant difference,the emulsion particle size and the particle size distribution index were all small,and the particle diameter curve showed single peak and narrow peak distribution,rust agent Ⅱ and the corrosion performance of the coating,as well as the rust emulsion Ⅱ to form the coating of the performance of the excellent,particle size is 44.75 nm,particle size distribution index of 0.541,uniform particle size distribution,the stability of the adhesion,a pencil hardness of HB,the coating water absorption is low,the salt-resistant coating 72 h,the Functional rust emulsion with a short dry time,good adhesion,good film,excellent corrosion resistance and other characteristics.The emulsion can be used for large-scale iron structures,buildings,bridges,offshore drilling platforms such as corrosion protection.