Study On Dispersion Of Inorganic Filler And Preparation Of Waterborne Anticorrosive Coating

Waterborne coatings are widely concerned by the industry and the science and technology circles due to their green and environmental advantages,which is one of the main development directions of coatings in the future.The use of color filler in waterborne paint system,not only can give paint film covering power and color,more important is to increase the anticorrosion performance of paint.The dispersion and stability of color filler is an important scientific and technical problem in the preparation of waterborne anticorrosive coatings.In this paper,aiming at the dispersion and stability of color filler in waterborne coatings,the dispersion state of particles in waterborne coatings and the influence of the synergistic effect of dispersant and rheological additives on the stability of suspension system were studied by using dynamic light scattering technology,and the thixotropic iron red paste with good stability was prepared.The obtained color paste was used in the preparation of water-based chlorine-containing anticorrosive coating.According to the characteristics of chlorine-containing emulsion,the paint formulation and process were studied,and the water-based iron red anticorrosive coating with excellent anticorrosive performance was prepared.The main research contents of this paper are as follows:1.By using dynamic light scattering technology,the dynamic stability of the dispersion system of water-based color paste with high density color fillers such as ferric oxide and barium sulfate was characterized by the information about particle changes and particle deposition given in the backscattering spectrum scanning graph.The stabilization effects of different dispersants and their dosage on the color paste system were studied.The experimental results show that the dispersant 6208 has the best effect,and 3%(as a percentage of the total mass of the color paste,the same as below)is finally determined as the optimal dosage of dispersant in the color paste system.2.The rheological assistant 6502 made by the laboratory was adopted.The use of the reagent made the color paste have too high viscosity in the static state,while the viscosity decreased rapidly under the action of slight shear,with good thixotropic liquidity.The effect of rheological additives was studied by Turbiscan Lab omnipotent stability analyzer.When the amount of rheological additives is 0.5%,and in collaboration with the dispersant,the packing particle settling rate is the smallest and the color paste is the most stable.Thus,The thixotropic red iron paste with solid content of 80%was prepared,which not only guarantees the storage stability of the paste but also meets the requirements of paint making and coating construction technology.3.Based on the excellent shielding characteristics of the chloro-acrylic emulsion currently in the pilot batch production in this laboratory,the preparation of the corresponding varnish was carried out.The types and dosage of defoaming agent,film-forming agent,pH regulator,thickening agent,rheological agent and chloride ion stabilizer were screened,and the optimized formulation and process of the varnish were finally determined.4.Aiming at the problem of flash rust in the construction of metal substrate by the water-based chloro-propyl anticorrosive coating,the anti-flash rust effect of various anti-flash rust agents and their recombination of the coating was studied,and it was found that the combination of sodium nitrite and ammonium hepamolybdate had good anti-flash rust effect.Through the comparison of anti-flash rust properties under different compounding ratios,it was finally determined that the compounding ratio of the two reagents was 1:1 optimal,and the coating was prepared into 15%(g/mL)aqueous solution,and the anti-flash rust effect was the best when the dosage was 0.3%of the emulsion amount.When the agent is used to solve the problem of flash rust,the amount of nitrite is reduced,and it has the least impact on the anti-corrosion performance of the coating compared with the commercial anti-flash rust agent.5.The prepared iron red paste was applied to the chlorinated acrylic emulsion to prepare the paint.When the paint was prepared according to the ratio of face to base of 0.5:1,it was found that the application of the color paste greatly improved the acid,alkali,salt,water,salt spray and other properties of the film,as well as the hardness and impact strength of the film,and the dispersion of the color paste in the emulsion was good.The prepared water-borne iron red chloride anti-corrosion coating was sent to the national building materials testing center for testing.Its performance was:Acid resistance(3%H2SO4),alkali(3.5%NaOH),salt(3.5%NaCl),water(grade ?water)are all 21d,salt fog resistance for 500h,aging resistance for 2000h without cracking,drumming,peeling and other phenomena,excellent paint performance.