A method for preparing water-based acrylic anticorrosive coating

Abstract

The present invention relates to the technical field of coatings, and discloses a method for preparing a water-based acrylic anticorrosive coating. The present invention uses PEPA and phosphorus pentoxide as raw materials to obtain bis-PEPA-based phosphate. Using 3-hydroxyglutaric acid, aminopropyltriethoxysilane, hexamethylene diisocyanate, graphene oxide, etc. as raw materials, bis-silane-modified graphene oxide is prepared. Add bis-silane-modified graphene oxide, bis-PEPA-based phosphate, etc. to the water-based acrylic emulsion, stir and mix evenly, grind and filter, and obtain a water-based acrylic anticorrosive coating. The present invention utilizes phosphorus hydroxyl, silicon hydroxyl, and graphene in the coating, and the three cooperate to assist in improving the adhesion and corrosion resistance of the coating, and utilize flame retardant elements to improve the flame retardant properties of the coating. The water-based acrylic anticorrosive coating prepared by the present invention has excellent anticorrosion performance, flame retardant properties, and adhesion.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, and in particular to a method for preparing a water-based acrylic anticorrosive coating. Background Art

[0002] Water-based anti-corrosion coatings use water as a solvent or dispersion medium. They are environmentally friendly and safe to use "green" anti-corrosion coatings, including water-based acrylic coatings, water-based epoxy coatings, and water-based polyurethane coatings. Among them, water-based acrylic anti-corrosion coatings have been widely used in metal, construction, textile, automobile and other fields due to their excellent weather resistance, color retention, pollution resistance, corrosion resistance and other properties. However, in recent years, the research and development, production and application of coatings have developed rapidly, and the existing traditional water-based acrylic anti-corrosion coatings can no longer meet the demand. Therefore, it is necessary to improve the anti-corrosion performance of water-based acrylic anti-corrosion coatings to meet the existing needs.

[0003] As a new material, graphene is widely used in coatings, batteries and other fields due to its excellent mechanical properties, chemical stability, conductivity and other properties. Pentaerythritol phosphate (PEPA) is a new flame retardant widely used in various flame retardant and fireproof fields.

[0004] For example, the patent with authorization announcement number CN 102702899 B discloses a water-based modified pure acrylic anti-corrosion coating. The invention uses modified acrylic emulsion, defoaming agent, wetting agent, etc. as raw materials. The anti-corrosion coating prepared has good anti-corrosion performance, but does not improve the flame retardant performance of the coating. Summary of the invention

[0005] The purpose of the present invention is to overcome one or more deficiencies in the prior art and to provide a water-based acrylic anti-corrosion coating. The prepared water-based acrylic anti-corrosion coating has excellent anti-corrosion performance, flame retardant performance and adhesion.

[0006] In order to achieve the above object, a technical solution adopted by the present invention is:

[0007] A method for preparing a water-based acrylic anticorrosive coating, the preparation method comprising:

[0008] (1) Add methyl methacrylate, styrene, butyl acrylate, isooctyl acrylate and acrylic acid into deionized water, stir and mix evenly, then add emulsifier, heat to 80-90°C, add initiator, keep warm and react for 2-5h, after the reaction is finished, use ammonia water to adjust the pH to 7-8, and obtain water-based acrylic emulsion;

[0009] (2) Adding water-based acrylic emulsion, dispersant, wetting agent, defoaming agent, disilane-modified graphene oxide, and bis-PEPA-based phosphate into deionized water, stirring and mixing evenly, grinding to a fineness of 10-25 μm, filtering, and obtaining a water-based acrylic anticorrosive coating.

[0010] In a preferred embodiment of the present invention, the mass ratio of methyl methacrylate, styrene, butyl acrylate, isooctyl acrylate and acrylic acid is 4-6:8-12:4-6:4-6:1.

[0011] In a preferred embodiment of the present invention, the emulsifier is one of sodium dodecyl sulfate and alkylphenol polyoxyethylene ether, and its usage is 2-5% of the total mass of methyl methacrylate, styrene, butyl acrylate, isooctyl acrylate and acrylic acid; the initiator is ammonium persulfate, and its usage is 0.5-1% of the total mass of methyl methacrylate, styrene, butyl acrylate, isooctyl acrylate and acrylic acid.

[0012] In a preferred embodiment of the present invention, the mass ratio of deionized water, aqueous acrylic emulsion, dispersant, wetting agent, defoamer, disilane-modified graphene oxide, and bis-PEPA-based phosphate is 10-30:100:0.1-0.5:0.3-0.6:0.2-0.5:2-10:1-5.

[0013] Preferably, in said (2), the preparation method for obtaining the bis-PEPA-based phosphate is as follows: PEPA is added to a tetrahydrofuran solvent, stirred and dispersed, phosphorus pentoxide is added thereto at 0-5°C, wherein the ratio of PEPA to phosphorus pentoxide is (1.8-2.2) mol:1 mol, the temperature is raised to 90-100°C, the reaction is carried out for 2-5 hours, after the reaction is completed, deionized water is added thereto, filtered, extracted with ethyl acetate, and dried to obtain the bis-PEPA-based phosphate.

[0014] Preferably, in (2), the preparation method of disilane-modified graphene oxide is:

[0015] A1: 3-Hydroxyglutaric acid is added to tetrahydrofuran solvent, stirred and dispersed, EDC·HCl is added thereto, stirred and mixed evenly, aminopropyltriethoxysilane is added thereto, and stirred and reacted at room temperature for 3-6 hours. After the reaction is completed, the mixture is washed with saturated sodium bicarbonate aqueous solution and saturated sodium chloride aqueous solution in sequence, dried, rotary evaporated, and dried to obtain intermediate 1;

[0016] A2: Add hexamethylene diisocyanate to butyl acetate solvent, stir evenly, add dibutyltin dilaurate, heat to 35-45°C, add intermediate 1, stir to react for 3-5h, wash with ethanol after the reaction is completed, and dry to obtain intermediate 2;

[0017] A3: Add graphene oxide to butyl acetate solvent, disperse by ultrasonication, heat to 70-80°C with stirring under nitrogen protection, add dibutyltin dilaurate and intermediate 2, react at constant temperature for 4-8h, filter after the reaction, wash with ethanol, and dry to obtain disilane-modified graphene oxide.

[0018] More preferably, in A1, the usage ratio of 3-hydroxyglutaric acid, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl), and aminopropyltriethoxysilane is 1 mol: (1-1.5) mol: (2-2.5) mol.

[0019] Further preferably, in A2, the usage ratio of hexamethylene diisocyanate to intermediate 1 is 1 mol: (0.8-1.2) mol.

[0020] Further preferably, in A3, the usage ratio of graphene oxide to intermediate 2 is 1 g: (0.03-0.07) mol.

[0021] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0022] (1) The present invention uses PEPA as a raw material and phosphorus pentoxide as a phosphorylation agent, and obtains a bis-PEPA-based phosphate through an esterification reaction. The carboxyl group in 3-hydroxyglutaric acid is subjected to an amidation reaction with aminopropyltriethoxysilane under the catalysis of EDC·HCl to obtain an intermediate 1, and hexamethylene diisocyanate is used as a bridge to react with the hydroxyl group in the intermediate 1 and the hydroxyl group in graphene oxide in sequence to obtain a bis-silane-modified graphene oxide. Methyl methacrylate and styrene are used as hard monomers, butyl acrylate and isooctyl acrylate are used as soft elastic bodies, and acrylic acid is used as a functional monomer. Under the initiation of ammonium persulfate, a water-based acrylic emulsion is obtained through free radical polymerization, and finally deionized water, a dispersant, a bis-silane-modified graphene oxide, a bis-PEPA-based phosphate, etc. are added thereto, stirred and mixed evenly, and ground and filtered to obtain a water-based acrylic anticorrosive coating.

[0023] (2) The water-based acrylic anticorrosive coating prepared by the present invention contains phosphorus hydroxyl groups, which have a strong chelating effect on the metal surface and can react with the metal to form a phosphate complex. The polymer is firmly attached to the metal surface in the form of a covalent bond, forming a dense phosphate protective film on the metal surface, which can not only improve the adhesion of the coating, but also improve the anticorrosion performance. In addition, the silicon-oxygen bonds contained therein can be hydrolyzed to produce silicon hydroxyl groups, which can not only react with the -OH of the metal substrate, but also can self-condense to form a protective film, further increasing the adhesion and anticorrosion performance of the coating.

[0024] (3) The water-based acrylic anti-corrosion coating prepared by the present invention contains graphene, which is combined with organic matter in the present invention to increase the dispersion of graphene in the coating, that is, the graphene can be evenly dispersed in the coating, thereby preventing the contact probability between corrosive substances and the base material, reducing the degree of base corrosion, and further improving the anti-corrosion performance.

[0025] (4) When combustion occurs, phosphorus-containing compounds are decomposed by heat into non-flammable liquid phosphoric acid film and metaphosphoric acid. Metaphosphoric acid can be further polymerized to form polymetaphosphoric acid. On the one hand, the sticky coating formed by phosphoric acid on the polymer surface plays a barrier role. On the other hand, polymetaphosphoric acid can catalyze the dehydration of polymer materials into carbon. The formed carbon film can effectively block flammable gases and change the combustion process of the material, thereby achieving a flame retardant effect. When the material burns, silicon-containing compounds can form a silicon layer with strong thermal stability on the surface of the material, effectively blocking the transfer of heat and flammable gases into the material, changing the combustion process and further improving the flame retardant effect of the material. The nitrogen-containing compounds will decompose during the combustion process to produce non-flammable gases such as nitrogen and nitrogen dioxide, which can effectively dilute the flammable gases in the air and take away some heat, further inhibiting the combustion process. The three form a phosphorus-nitrogen-silicon synergistic flame retardant system, which can effectively improve the flame retardant effect of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the reaction route of bis-PEPA-based phosphate;

[0027] Figure 2 This is the reaction route for the modification of graphene oxide by disilane. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] Preparation method of PEPA: add 68g of pentaerythritol and 46mL of phosphorus oxychloride into a flask filled with dioxane solvent, heat to 80°C, react for 1h, continue to heat to 100°C, continue reflux reaction for 5h, after the reaction is completed, cool to room temperature, filter, wash with dioxane, recrystallize, and dry to obtain PEPA.

[0030] Preparation method of graphene oxide: add 1 g of graphene to 200 mL of mixed acid (sulfuric acid and nitric acid in a volume ratio of 3:1), ultrasonically disperse for 30 minutes, reflux and stir at 80°C for 30 minutes, cool to room temperature after the reaction, add deionized water, centrifuge, filter, and dry to obtain graphene oxide.

[0031] The dispersant is dispersant BYK346;

[0032] The wetting agent is wetting agent TOK-W77:

[0033] The defoamer is water-based defoamer Tego 810. Embodiment 1

[0034] (1) 0.18 mol of PEPA was added to tetrahydrofuran solvent, stirred and dispersed, 0.1 mol of phosphorus pentoxide was added thereto at 5°C, the temperature was raised to 95°C, and the reaction was carried out for 5 hours. After the reaction was completed, deionized water was added thereto, the mixture was filtered, extracted with ethyl acetate, and dried to obtain bis-PEPA phosphate.

[0035] (2) Add 0.2 mol of 3-hydroxyglutaric acid to tetrahydrofuran solvent and stir to disperse. Add 0.25 mol of EDC·HCl to the mixture and stir to mix evenly. Then add 0.5 mol of aminopropyltriethoxysilane to the mixture and stir to react at room temperature for 5 h. After the reaction is completed, wash with saturated sodium bicarbonate aqueous solution and saturated sodium chloride aqueous solution in sequence, dry, and rotary evaporate to dry to obtain intermediate 1.

[0036] (3) Add 0.04 mol of hexamethylene diisocyanate to butyl acetate solvent, stir evenly, add 3 drops of dibutyltin dilaurate, raise the temperature to 40°C, add 0.045 mol of intermediate 1, stir and react for 4 h. After the reaction is completed, wash with ethanol and dry to obtain intermediate 2.

[0037] (4) Add 5 g of graphene oxide to butyl acetate solvent, disperse by ultrasonication, and heat to 75 °C with stirring under nitrogen protection. Add 6 drops of dibutyltin dilaurate and 0.3 mol of intermediate 2, and react at a constant temperature for 8 h. After the reaction is completed, filter, wash with ethanol, and dry to obtain disilane-modified graphene oxide.

[0038] (5) Add 20 g of methyl methacrylate, 40 g of styrene, 20 g of butyl acrylate, 25 g of isooctyl acrylate, and 5 g of acrylic acid into deionized water, stir and mix evenly, then add 4 g of sodium dodecyl sulfate emulsifier, raise the temperature to 90°C, add 1 g of ammonium persulfate initiator, keep the temperature for reaction for 2 h, and after the reaction is completed, use ammonia water to adjust the pH to 8 to obtain a water-based acrylic emulsion.

[0039] (6) Add 100 g of aqueous acrylic emulsion, 0.4 g of dispersant, 0.5 g of wetting agent, 0.3 g of defoaming agent, 2 g of disilane-modified graphene oxide, and 1 g of bis-PEPA-based phosphate to 20 g of deionized water, stir and mix evenly, grind to a fineness of 25 μm, and filter to obtain a water-based acrylic anti-corrosion coating. Embodiment 2

[0040] (1) Add 0.22 mol of PEPA to tetrahydrofuran solvent, stir and disperse, add 0.1 mol of phosphorus pentoxide at 0°C, heat to 100°C, react for 2 hours, add deionized water after the reaction, filter, extract with ethyl acetate, and dry to obtain bis-PEPA phosphate.

[0041] (2) Add 0.2 mol of 3-hydroxyglutaric acid to tetrahydrofuran solvent and stir to disperse. Add 0.25 mol of EDC·HCl to the mixture and stir to mix evenly. Then add 0.5 mol of aminopropyltriethoxysilane to the mixture and stir to react at room temperature for 5 h. After the reaction is completed, wash with saturated sodium bicarbonate aqueous solution and saturated sodium chloride aqueous solution in sequence, dry, and rotary evaporate to dry to obtain intermediate 1.

[0042] (3) Add 0.04 mol of hexamethylene diisocyanate to butyl acetate solvent, stir evenly, add 3 drops of dibutyltin dilaurate, raise the temperature to 40°C, add 0.048 mol of intermediate 1, stir and react for 4 h. After the reaction is completed, wash with ethanol and dry to obtain intermediate 2.

[0043] (4) Add 5 g of graphene oxide to butyl acetate solvent, disperse by ultrasonication, and heat to 80°C with stirring under nitrogen protection. Add 5 drops of dibutyltin dilaurate and 0.3 mol of intermediate 2, and react at a constant temperature for 5 h. After the reaction is completed, filter, wash with ethanol, and dry to obtain disilane-modified graphene oxide.

[0044] (5) Add 20 g of methyl methacrylate, 50 g of styrene, 30 g of butyl acrylate, 30 g of isooctyl acrylate and 5 g of acrylic acid into deionized water, stir and mix evenly, then add 6.75 g of alkylphenol polyoxyethylene ether emulsifier, raise the temperature to 85°C, add 1.2 g of ammonium persulfate initiator, keep the temperature for reaction for 3 hours, and after the reaction is completed, use ammonia water to adjust the pH to 8 to obtain a water-based acrylic emulsion.

[0045] (6) Add 100 g of aqueous acrylic emulsion, 0.1 g of dispersant, 0.6 g of wetting agent, 0.2 g of defoaming agent, 4 g of disilane-modified graphene oxide, and 2 g of bis-PEPA-based phosphate to 30 g of deionized water, stir and mix evenly, grind to a fineness of 10 μm, and filter to obtain a water-based acrylic anti-corrosion coating. Embodiment 3

[0046] (1) Add 0.2 mol of PEPA to tetrahydrofuran solvent, stir and disperse, add 0.1 mol of phosphorus pentoxide at 0°C, raise the temperature to 90°C, react for 5 hours, add deionized water after the reaction, filter, extract with ethyl acetate, and dry to obtain bis-PEPA phosphate.

[0047] (2) Add 0.2 mol of 3-hydroxyglutaric acid to tetrahydrofuran solvent, stir and disperse, then add 0.2 mol of EDC·HCl, stir and mix evenly, then add 0.5 mol of aminopropyltriethoxysilane, stir and react at room temperature for 5 h. After the reaction is completed, wash with saturated sodium bicarbonate aqueous solution and saturated sodium chloride aqueous solution, dry, rotary evaporate, and dry to obtain intermediate 1.

[0048] (3) Add 0.04 mol of hexamethylene diisocyanate to butyl acetate solvent, stir evenly, add 1 drop of dibutyltin dilaurate, raise the temperature to 35°C, add 0.04 mol of intermediate 1, stir and react for 3 h. After the reaction is completed, wash with ethanol and dry to obtain intermediate 2.

[0049] (4) Add 5 g of graphene oxide to butyl acetate solvent, disperse by ultrasonication, and heat to 75 °C with stirring under nitrogen protection. Add 7 drops of dibutyltin dilaurate and 0.2 mol of intermediate 2, and react at a constant temperature for 6 h. After the reaction is completed, filter, wash with ethanol, and dry to obtain disilane-modified graphene oxide.

[0050] (5) Add 25 g of methyl methacrylate, 60 g of styrene, 25 g of butyl acrylate, 30 g of isooctyl acrylate, and 5 g of acrylic acid into deionized water, stir and mix evenly, then add 5.8 g of sodium dodecyl sulfate emulsifier, raise the temperature to 90°C, add 1.4 g of ammonium persulfate initiator, and keep the temperature to react for 4 hours. After the reaction is completed, use ammonia water to adjust the pH to 8 to obtain a water-based acrylic emulsion.

[0051] (6) Add 100 g of aqueous acrylic emulsion, 0.5 g of dispersant, 0.3 g of wetting agent, 0.5 g of defoaming agent, 6 g of disilane-modified graphene oxide, and 3 g of bis-PEPA-based phosphate to 10 g of deionized water, stir and mix evenly, grind to a fineness of 15 μm, and filter to obtain a water-based acrylic anti-corrosion coating. Embodiment 4

[0052] (1) Add 0.2 mol of PEPA to tetrahydrofuran solvent, stir and disperse, add 0.1 mol of phosphorus pentoxide at 5°C, raise the temperature to 100°C, react for 4 hours, add deionized water after the reaction, filter, extract with ethyl acetate, and dry to obtain bis-PEPA phosphate.

[0053] (2) Add 0.2 mol of 3-hydroxyglutaric acid to tetrahydrofuran solvent, stir and disperse, then add 0.25 mol of EDC·HCl, stir and mix evenly, then add 0.45 mol of aminopropyltriethoxysilane, stir and react at room temperature for 6 hours. After the reaction is completed, wash with saturated sodium bicarbonate aqueous solution and saturated sodium chloride aqueous solution, dry, rotary evaporate, and dry to obtain intermediate 1.

[0054] (3) Add 0.04 mol of hexamethylene diisocyanate to butyl acetate solvent, stir evenly, add 2 drops of dibutyltin dilaurate, raise the temperature to 40°C, add 0.032 mol of intermediate 1, stir and react for 5 h. After the reaction is completed, wash with ethanol and dry to obtain intermediate 2.

[0055] (4) Add 5 g of graphene oxide to butyl acetate solvent, disperse by ultrasonication, and heat to 80°C with stirring under nitrogen protection. Add 5 drops of dibutyltin dilaurate and 0.15 mol of intermediate 2, and react at a constant temperature for 4 h. After the reaction is completed, filter, wash with ethanol, and dry to obtain disilane-modified graphene oxide.

[0056] (5) Add 30 g of methyl methacrylate, 60 g of styrene, 20 g of butyl acrylate, 20 g of isooctyl acrylate and 5 g of acrylic acid into deionized water, stir and mix evenly, then add 5.4 g of alkylphenol polyoxyethylene ether emulsifier, raise the temperature to 80°C, add 1.35 g of ammonium persulfate initiator, keep the temperature for reaction for 5 h, and after the reaction is completed, use ammonia water to adjust the pH to 8 to obtain a water-based acrylic emulsion.

[0057] (6) Add 100 g of aqueous acrylic emulsion, 0.4 g of dispersant, 0.5 g of wetting agent, 0.5 g of defoaming agent, 8 g of disilane-modified graphene oxide, and 4 g of bis-PEPA-based phosphate to 20 g of deionized water, stir and mix evenly, grind to a fineness of 25 μm, and filter to obtain a water-based acrylic anticorrosive coating. Embodiment 5

[0058] (1) Add 0.2 mol of PEPA to tetrahydrofuran solvent, stir and disperse, add 0.1 mol of phosphorus pentoxide at 5°C, raise the temperature to 100°C, react for 4 hours, add deionized water after the reaction, filter, extract with ethyl acetate, and dry to obtain bis-PEPA phosphate.

[0059] (2) Add 0.2 mol of 3-hydroxyglutaric acid to tetrahydrofuran solvent, stir and disperse, then add 0.3 mol of EDC·HCl, stir and mix evenly, then add 0.4 mol of aminopropyltriethoxysilane, stir and react at room temperature for 3 h. After the reaction is completed, wash with saturated sodium bicarbonate aqueous solution and saturated sodium chloride aqueous solution, dry, and rotary evaporate to dry to obtain intermediate 1.

[0060] (3) Add 0.04 mol of hexamethylene diisocyanate to butyl acetate solvent, stir evenly, add 3 drops of dibutyltin dilaurate, raise the temperature to 45°C, add 0.048 mol of intermediate 1, stir and react for 4 h. After the reaction is completed, wash with ethanol and dry to obtain intermediate 2.

[0061] (4) 5 g of graphene oxide was added to butyl acetate solvent and ultrasonically dispersed. Under nitrogen protection, the mixture was stirred and heated to 70°C. 4 drops of dibutyltin dilaurate and 0.35 mol of intermediate 2 were added and the mixture was reacted at a constant temperature for 8 h. After the reaction was completed, the mixture was filtered, washed with ethanol, and dried to obtain disilane-modified graphene oxide.

[0062] (5) Add 20 g of methyl methacrylate, 40 g of styrene, 20 g of butyl acrylate, 25 g of isooctyl acrylate and 5 g of acrylic acid into deionized water, stir and mix well, then add 2 g of alkylphenol polyoxyethylene ether emulsifier, raise the temperature to 85°C, add 0.5 g of ammonium persulfate initiator, keep the temperature for 4 hours, and after the reaction is completed, use ammonia water to adjust the pH to 7 to obtain a water-based acrylic emulsion.

[0063] (6) Add 100 g of aqueous acrylic emulsion, 0.5 g of dispersant, 0.4 g of wetting agent, 4 g of defoaming agent, 10 g of disilane-modified graphene oxide, and 5 g of bis-PEPA-based phosphate to 20 g of deionized water, stir and mix evenly, grind to a fineness of 25 μm, and filter to obtain a water-based acrylic anticorrosive coating.

[0064] Comparative Example 1

[0065] (1) 0.2 mol of 3-hydroxyglutaric acid was added to tetrahydrofuran solvent and stirred to disperse. Then, 0.25 mol of EDC·HCl was added thereto and stirred to mix evenly. Then, 0.5 mol of aminopropyltriethoxysilane was added thereto and stirred to react at room temperature for 5 h. After the reaction was completed, the mixture was washed with saturated sodium bicarbonate aqueous solution and saturated sodium chloride aqueous solution in sequence, dried, and rotary evaporated to dry to obtain intermediate 1.

[0066] (2) Add 0.04 mol of hexamethylene diisocyanate to butyl acetate solvent, stir evenly, add 3 drops of dibutyltin dilaurate, raise the temperature to 40°C, add 0.045 mol of intermediate 1, stir and react for 4 hours. After the reaction is completed, wash with ethanol and dry to obtain intermediate 2.

[0067] (3) Add 5 g of graphene oxide to butyl acetate solvent, disperse by ultrasonication, and heat to 75 °C with stirring under nitrogen protection. Add 6 drops of dibutyltin dilaurate and 0.3 mol of intermediate 2, and react at a constant temperature for 8 h. After the reaction is completed, filter, wash with ethanol, and dry to obtain disilane-modified graphene oxide.

[0068] (4) Add 20 g of methyl methacrylate, 40 g of styrene, 20 g of butyl acrylate, 25 g of isooctyl acrylate, and 5 g of acrylic acid into deionized water, stir and mix evenly, then add 4 g of sodium dodecyl sulfate emulsifier, raise the temperature to 90°C, add 1 g of ammonium persulfate initiator, keep the temperature for reaction for 2 h, and after the reaction is completed, use ammonia water to adjust the pH to 8 to obtain a water-based acrylic emulsion.

[0069] (5) Add 100 g of aqueous acrylic emulsion, 0.4 g of dispersant, 0.5 g of wetting agent, 0.3 g of defoaming agent, and 2 g of disilane-modified graphene oxide into 20 g of deionized water, stir and mix evenly, grind to a fineness of 25 μm, and filter to obtain a water-based acrylic anticorrosive coating.

[0070] Comparative Example 2

[0071] (1) 0.18 mol of PEPA was added to tetrahydrofuran solvent, stirred and dispersed, 0.1 mol of phosphorus pentoxide was added thereto at 5°C, the temperature was raised to 95°C, and the reaction was carried out for 5 hours. After the reaction was completed, deionized water was added thereto, the mixture was filtered, extracted with ethyl acetate, and dried to obtain bis-PEPA phosphate.

[0072] (2) Add 100 g of aqueous acrylic emulsion, 0.4 g of dispersant, 0.5 g of wetting agent, 0.3 g of defoaming agent, and 1 g of bis-PEPA-based phosphate to 20 g of deionized water, stir and mix well, grind to a fineness of 25 μm, and filter to obtain a water-based acrylic anticorrosive coating.

[0073] The coating is applied on a clean and dry tinplate substrate, dried naturally at room temperature, and maintained for one week to obtain a cured coating.

[0074] Flame retardant performance test: Use an oxygen index tester to test the oxygen index of the coating. The higher the oxygen index, the better the flame retardant performance of the material.

[0075] Table 1:

[0076]

[0077] It can be seen from the table that the flame retardant effect of Examples 1-5 is better than that of Comparative Examples 1-2, indicating that the flame retardant effect of the phosphorus-nitrogen-silicon synergistic flame retardant system is better.

[0078] Adhesion performance test: Use a grid tool to vertically score the cured coating, stick tape on the grid and quickly tear it off, observe the integrity of the coating, and the evaluation standard is divided into 6 levels, from 0 to 5, where 5 is the worst and 0 is the best.

[0079] Table 2:

[0080]

[0081] It can be seen from the table that the coating prepared by the present invention has good adhesion.

[0082] Corrosion resistance test: Place the cured coating in a medium including water, acid (10% by mass HCl), and alkali (10% by mass NaOH). Take it out after 200 hours and use filter paper to check for bubbling and rusting.

[0083] Table 3:

[0084]

[0085] It can be seen from the table that the coating prepared by the present invention has good anti-corrosion performance.

[0086] Although the invention has been described herein with reference to illustrative embodiments thereof, it should be understood that numerous other modifications and implementations can be devised by those skilled in the art that will fall within the scope and spirit of the principles disclosed herein.

Claims

1. A method for preparing a water-based acrylic anticorrosive coating, characterized in that: The preparation method is: (1) adding methyl methacrylate, styrene, butyl acrylate, isooctyl acrylate and acrylic acid into deionized water, stirring and mixing evenly, adding an emulsifier thereto, heating to 80-90° C., adding an initiator thereto, and keeping the temperature for reaction for 2-5 hours. After the reaction is completed, adjusting the pH to 7-8 with aqueous ammonia to obtain an aqueous acrylic emulsion; (2) adding an aqueous acrylic emulsion, a dispersant, a wetting agent, a defoamer, a disilane-modified graphene oxide, and a bis-PEPA-based phosphate to deionized water, stirring and mixing the mixture evenly, grinding the mixture to a fineness of 10-25 μm, and filtering the mixture to obtain a water-based acrylic anticorrosive coating; The preparation method of the bis-PEPA-based phosphate is as follows: PEPA is added to a tetrahydrofuran solvent, stirred and dispersed, phosphorus pentoxide is added thereto at 0-5°C, the temperature is raised to 90-100°C, the reaction is carried out for 2-5 hours, after the reaction is completed, deionized water is added thereto, filtered, extracted with ethyl acetate, and dried to obtain the bis-PEPA-based phosphate; The preparation method of the bisilane-modified graphene oxide is: A1: 3-Hydroxyglutaric acid is added to tetrahydrofuran solvent, stirred and dispersed, EDC·HCl is added thereto, stirred and mixed evenly, aminopropyltriethoxysilane is added thereto, and stirred and reacted at room temperature for 3-6 hours. After the reaction is completed, the mixture is washed with saturated sodium bicarbonate aqueous solution and saturated sodium chloride aqueous solution in sequence, dried, rotary evaporated, and dried to obtain intermediate 1; A2: Add hexamethylene diisocyanate to butyl acetate solvent, stir evenly, add dibutyltin dilaurate, heat to 35-45°C, add intermediate 1, stir to react for 3-5h, wash with ethanol after the reaction is completed, and dry to obtain intermediate 2; A3: Add graphene oxide to butyl acetate solvent, disperse by ultrasonication, heat to 70-80°C with stirring under nitrogen protection, add dibutyltin dilaurate and intermediate 2, react at constant temperature for 4-8h, filter after the reaction, wash with ethanol, and dry to obtain disilane-modified graphene oxide.

2. The method for preparing the water-based acrylic anticorrosive coating according to claim 1, characterized in that: In the above (1), the mass ratio of methyl methacrylate, styrene, butyl acrylate, isooctyl acrylate and acrylic acid is 4-6:8-12:4-6:4-6:

1.

3. The method for preparing the water-based acrylic anticorrosive coating according to claim 1, characterized in that: In the above (1), the emulsifier is one of sodium dodecyl sulfate and alkylphenol polyoxyethylene ether, and its usage is 2-5% of the total mass of methyl methacrylate, styrene, butyl acrylate, isooctyl acrylate and acrylic acid; the initiator is ammonium persulfate, and its usage is 0.5-1% of the total mass of methyl methacrylate, styrene, butyl acrylate, isooctyl acrylate and acrylic acid.

4. The method for preparing the water-based acrylic anticorrosive coating according to claim 1, characterized in that: In the method (2), the mass ratio of deionized water, aqueous acrylic emulsion, dispersant, wetting agent, defoaming agent, disilane-modified graphene oxide, and bis-PEPA-based phosphate is 10-30:100:0.1-0.5:0.3-0.6:0.2-0.5:2-10:1-5.

5. The method for preparing the water-based acrylic anticorrosive coating according to claim 1, characterized in that: The usage ratio of PEPA and phosphorus pentoxide is (1.8-2.2) mol:1 mol.

6. The method for preparing the water-based acrylic anticorrosive coating according to claim 1, characterized in that: In the A1, the usage ratio of 3-hydroxyglutaric acid, EDC·HCl, and aminopropyltriethoxysilane is 1 mol:(1-1.5) mol:(2-2.5) mol.

7. The method for preparing the water-based acrylic anticorrosive coating according to claim 1, characterized in that: In the A2, the usage ratio of hexamethylene diisocyanate and intermediate 1 is 1 mol:(0.8-1.2) mol.

8. The method for preparing the water-based acrylic anticorrosive coating according to claim 1, characterized in that: In A3, the usage ratio of graphene oxide and intermediate 2 is 1g:(0.03-0.07)mol.

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