| In recent years,most of the coatings in the whole coating market are solvent-based coatings.However,with the continuous development of society,the enhancement of people’s environmental awareness,and the limitations of relevant national laws and regulations,solventbased coatings have exposed problems such as environmental damage and harm to human health.It is of great practical significance to study and prepare solvent-free coatings.The physical properties of coatings are mainly provided by coating materials,so the preparation of solvent-free coating materials with excellent physical properties,environmental protection and non-toxic is a hot topic in the coating industry.The solvent-free coating material will not produce volatile organic compounds(VOCs)during the production and curing process.It is green and environmentally friendly.The physical properties of the film-formed coating are equivalent to those of the solvent-based coating.Solvent-free coatings can solve the environmental protection problems of solvent based coatings,as well as the construction and transportation problems of water-based coatings.Therefore,the research of solvent free coatings has useful significance.In China,the economic losses caused by metal corrosion are huge,and huge investments are required every year to solve this problem.Surface coating is the most economical and practical method to solve the problem of metal corrosion.Epoxy resin anticorrosive coating has excellent corrosion resistance,stable chemical properties,acid and alkali resistance,and excellent comprehensive performance.However,its impermeability is poor,and a large number of hydrophilic groups cause it to easily absorb water and swell,damage the coating structure,and do not have the ability of long-term corrosion prevention,and the large viscosity of epoxy resin is not convenient for practical construction.The side chain of fluorinated polyacrylic acid resin contains fluorine atoms,which has the characteristics of water repellency,water and oil repellent,oxidation resistance,good anticorrosion performance and other characteristics,used in surfactants,,electronic fiber,coating and coating.Moreover,the stable viscosity of the resin system is small,and the color will not change to yellow under high temperature,so the construction is simple and convenient.In this paper,solvent-free fluorinated acrylate is selected as the main film-forming material of solventfree fluorinated polyacrylate resin,and then mixed with epoxy resin to form a film to prepare solvent-free anti-corrosion coating.The surface of the coating is flat and free of bubbles,the surface energy of fluorinated polyacrylate is low,incompatible with epoxy resin and phase separation will occur.Fluorinated polyacrylate will migrate to the upper layer of the mixed coating,and form a dense "hydrophobic layer" after cross-linking and curing,The epoxy resin has strong adhesion and provides strong adhesion on the lower layer of the mixed coating,forming a structure of "hydrophobic layer+adhesive".The disadvantages of the two complement each other,and the advantages are superimposed on each other,so get environmentally friendly,water and oil repellent,strong adhesion anti-corrosion coating.The silicone polymer material mainly contains siloxane groups,and the low surface energy functional groups make the resin have excellent water repellent and antifouling ability,high hardness,UV resistance and other characteristics.However,the silicone resin is difficult to cure into a film at room temperature,and needs high temperature to cure to form a film,and the silicone resin can not be well attached to the substrate.A small amount of silicone polymer has little impact on the coating modification effect,Adding a large amount of organosilicon polymer will produce agglomerates and the organosilicon polymer will undergo condensation and crosslinking,which will affect the modification effect.In this paper,we prepared solvent-free fluorine-containing(silicon)polyacrylate functional polymer and explored its physical structure and corrosion resistance after polymer modification.The main research contents are as follows:(1)First,The solvent-free fluorinated polyacrylate was prepared by atom transfer radical polymerization using dodecafluoroheptyl methacrylate and glycidyl methacrylate as raw materials.The synthesized solvent-free fluorinated polyacrylate contains epoxy groups and low surface energy functional groups,which are physically mixed with epoxy resin to form a selflayered coating.The fluorinated low surface energy functional groups will migrate and concentrate on the surface of the mixed coating,The epoxy resin provides strong adhesion on the lower layer of the mixed coating.The solvent-free anti-corrosion coating is formed after the epoxy resin curing agent is used to open the ring and dry the film.The "hydrophobic layer+adhesive" structure can not only prevent the immersion of anti-corrosion media,but also provide strong adhesion for the mixed resin.Research shows that the addition of Fluorinated polyacrylate not only improves the water contact angle and compactness of the coating film,but also enhances the anti-corrosion performance of the mixed coating.(2)The long chain fluoropolymers are not only expensive,but also have high biological toxicity after degradation.On the basis of the above preparation of solvent-free fluorinated polyacrylate γ-The methacryloxypropyltrimethylsilane(KH570)organosilicon polymer,instead of some fluorinated polyesters,successfully prepared fluorosilicone polyacrylate through electron atom transfer radical polymerization.The fluorosilicone synergy effect further enables the low surface energy groups to migrate to the surface layer,enhances the ability of the coating to resist corrosive media,and the siloxane can react with the hydroxyl groups in the epoxy resin to form covalent bonds,consuming the hydrophilic groups in the epoxy resin,The prepared mixed coating has good hardness,high strength,good compactness,low cost and strong operability. |
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