Preparation Of Waterborne Epoxy Zinc-rich Coating

At present,social science and technology are constantly updated,people's material and cultural level is constantly improving,and environmental awareness is constantly strengthening.Infrastructure is inseparable from the use of paint.Therefore,in response to the call for environmental protection,solvent-based coatings are gradually being used by water-soluble coatings.Instead,its excellent low VOC greatly reduces the harm of the coating solvent to the human body,and also reduces the air pollution.Waterborne epoxy zinc-rich coatings with epoxy resin as the main film-forming substrate in waterborne coatings are typical materials for anti-corrosion engineering,so the water-based epoxy zinc-rich coatings with excellent preparation performance and low cost in construction universities are today's zinc-rich coatings.The inevitable trend of development.In this paper,the surface modification method was used to graft the aminosilane coupling agent onto the surface of zinc powder to prepare a silane film covered with silica and amino groups.The two small molecule modifiers were used for comparison and preferred extraction.The agglomeration problem in the zinc aqueous phase ensures the stability of the modified zinc in the weakly alkaline coating system,and at the same time guarantees the characteristics of the electrochemical corrosion protection of the zinc powder.Then,based on the same emulsion,a three-component,modified two-component waterborne epoxy zinc-rich paint was prepared.Adding wetting and dispersing agent as another way to prepare two-component color lacquer,and comparing it with the zine-modified method by experiment,comparing the feasibility and advantages and disadvantages of the two,systematically evaluating the modified zinc The degree of coating,the application effect in the coating,and the storage stability.The main research contents are as follows:1.A varnish and a three-component waterborne epoxy zinc-rich paint were prepared by using 384W emulsion as a film-forming substance.The pigment and filler systems were pure flakes,pure spheres and mixed pigments.By changing the dosage and proportion of pigments and fillers,the selection of additives and the optimization of curing conditions to ensure stable dispersion,pure zinc paint,pure zinc paint and mixed pigment system color are prepared.paint.The results show that the addition of flaky zinc powder has great influence on the mechanical stability of the emulsion without any modification.The performance of the coating is basically dependent on the content of zinc,which is positively correlated,but the unmodified zinc is applied.In the waterborne coating system,only three-component color paint can be prepared.The most resistant mixed pigment and filler system has the resistance to medium properties:41 days of deionized water;55 days of salt water resistance;and 19 days of salt spray resistance.However,the storage stability is not good,and a large amount of bubbles are generated in the oven at 50? for 2 hours.2.TEOS and KH550 two small molecule modifiers were used to modify the polar surface of zinc sheet.By control the ratio of zinc to silicon,water to silicon ratio,the surface was coated with silica and Partial amino modified zinc was characterized by XPS,EDS.The synthesis of modified zinc was evaluated by water contact angle,stability of powder in the medium and hydrogen evolution.performance.The results show that the silane film formed by the zinc coating of TEOS is thicker,which is not conducive to the protection in the later application.The silane film of KH550 coated zinc is stable under weak alkaline medium,unstable in brine medium and produces more The bubbles,in the acidic medium,will generate a large amount of hydrogen when heated and stirred,which is beneficial to the zinc storage under the weak alkaline storage and other mediums which are not conducive to the storage of the metal powder.3.The feasibility of preparing a two-component color paint by wetting and dispersing agent is negated,and the water resistance is extremely poor,and the film performance cannot be guaranteed.At the same time,the dispersibility of the modified zinc is improved,and the pigment paint is improved by the pigment base.The storage stability of the mixed paint prepared by the modified zinc is evaluated by rheological test.According to the final resistance to medium properties,the optimal process plan for modified zinc is determined.The results showed that the sedimentation problem of the coating was solved under the dosage of 0.5%bentonite thickener.At the same time,the storage time of the coating was determined.The oven was stored at 50? for 168 hours(seven days).The dielectric properties of the removed paint were:deionization resistance.Water for 41 days;salt water for 74 days;salt spray for 18 days.The modified zinc process is:zinc to silicon ratio 20.2,water to silicon ratio 6.1,reaction temperature 50?,reaction time 1 h.