Anticorrosive paint for metal protection and preparation method thereof

Abstract

The invention relates to the technical field of anti-corrosion coatings, and particularly discloses an anti-corrosion coating for metal protection and a preparation method thereof.According to the anti-corrosion coating provided by the invention, organic silicon modified epoxy resin is introduced, and residual internal stress generated during high crosslinking curing of the resin is effectively released through a flexible silicon-oxygen chain segment of the organic silicon modified epoxy resin; the defects that a traditional epoxy coating is large in rigidity and prone to embrittlement are remarkably overcome, and meanwhile the coating surface is endowed with the good hydrophobic characteristic. The composite modified filler effectively eliminates micro-pores caused by filler agglomeration through a physical shielding effect, a chemical anti-corrosion function of zinc phosphate and an interface covalent cross-linking synergistic effect of polar groups and resin, so that the anti-corrosion performance and adhesive force of the coating are improved, and long-acting comprehensive protection on a metal substrate is realized.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion coating technology, specifically to an anti-corrosion coating for metal protection and its preparation method. Background Technology

[0002] Metallic materials, due to their excellent mechanical properties and processing characteristics, play an irreplaceable role in major national infrastructure fields such as marine engineering, petrochemicals, transportation, and aerospace. However, metallic substrates are highly susceptible to corrosion from moisture, oxygen, chloride ions, and various acidic and alkaline media in complex service environments, resulting in severe electrochemical corrosion. This corrosion not only leads to a sharp decline in the mechanical strength of equipment and metal structural components, causing incalculable safety hazards, but also results in huge direct and indirect economic losses. To effectively curb this destructive process, applying anti-corrosion coatings to metal surfaces has become the most widely used, economical, and efficient protective method in industry. Anti-corrosion coatings can construct a continuous and dense physical barrier on the metal surface through film-forming substances, directly blocking the contact path between corrosive media and the metal substrate; simultaneously, with the active chemical passivation or cathodic protection of specific rust-inhibiting pigments and fillers, the occurrence and spread of corrosion reactions can be greatly delayed, thereby significantly extending the service life of metal structural components and ensuring the safety and long-term stability of industrial production.

[0003] Among numerous anti-corrosion coating systems, epoxy resin coatings dominate the heavy-duty anti-corrosion coating field due to their superior adhesion, excellent chemical resistance, and outstanding film density. Meanwhile, to further enhance the physical shielding and anti-corrosion performance of the coating, existing technologies typically incorporate a large amount of physically blended inorganic rust-inhibiting pigments and fillers into the epoxy matrix. However, these rigid inorganic particles have high surface energy and extremely poor interfacial compatibility with the organic resin matrix, making them prone to agglomeration and phase separation during the coating curing process. This simple physical blending not only fails to achieve the ideal "maze" shielding effect but also inevitably forms numerous micropores and defect channels at the interface between the inorganic filler and the organic resin. This allows water molecules and corrosive ions to easily penetrate to the underlying metal surface, making it difficult for existing epoxy anti-corrosion coatings to meet the long-term anti-corrosion requirements under harsh corrosive environments. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide an anti-corrosion coating for metal protection and a method for preparing the same.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: An anti-corrosion coating for metal protection comprises component A and component B. By weight, component A comprises the following raw materials: 80-100 parts epoxy resin, 10-20 parts silicone-modified epoxy resin, 20-40 parts composite modified filler, 1-5 parts dispersant, 0.5-2 parts defoamer, 0.2-0.5 parts leveling agent, and 40-60 parts deionized water; component B is a polyamide curing agent.

[0006] In the technical solution disclosed in this invention, epoxy resin is used as the main film-forming base material of the anti-corrosion coating, providing the coating with basic mechanical strength and adhesion. The weight parts of epoxy resin can be selected as 80 parts, 82 parts, 85 parts, 88 parts, 90 parts, 92 parts, 95 parts, 98 parts, or 100 parts, but are not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0007] In the technical solution disclosed in this invention, by adding silicone-modified epoxy resin, the volume shrinkage rate during coating curing can be effectively reduced, the curing internal stress can be absorbed and released, and the flexibility and impact resistance of the coating can be greatly improved. The weight parts of silicone-modified epoxy resin can be selected as 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, or 20 parts, but are not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0008] In the technical solution disclosed in this invention, the anti-corrosion performance and adhesion of the anti-corrosion coating are improved by adding composite modified filler. The weight parts of the composite modified filler can be selected as 20 parts, 22 parts, 24 parts, 25 parts, 28 parts, 30 parts, 35 parts, 38 parts, or 40 parts, but are not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0009] In the technical solution disclosed in this invention, the preparation method of the composite modified filler is as follows: S1. Disperse mica powder in deionized water, then add soluble zinc salt and stir to adsorb. Then, while stirring, add phosphate solution dropwise. After the addition is completed, age the solution, filter, wash and dry to obtain zinc phosphate / mica powder material. S2. Disperse zinc phosphate / mica powder material in an ethanol aqueous solution, adjust the pH of the solution to 6.8-7.2 using an acetic acid-ammonia buffer system, then add tetraethyl orthosilicate, stir, and after aging, filtration, washing, and drying, obtain the composite filler. S3. Disperse the composite filler in an ethanol aqueous solution, then add 3-(trimethoxysilyl)propyl methacrylate, stir, filter, wash and dry to obtain the double bond grafted composite filler. S4. Disperse the double bond grafted composite filler in an organic solvent, then add dodecafluoroheptyl methacrylate and hydroxyethyl methacrylate to it, stir evenly, then add the initiator benzoyl peroxide, heat and stir the reaction under a nitrogen atmosphere, and after the reaction is completed, filter, wash and dry to obtain the composite modified filler.

[0010] Specifically, in step S1, the mass ratio of mica powder, soluble zinc salt, and phosphate solution is 10:1-3:15-25, wherein the mass fraction of phosphate solution is 5-10%.

[0011] In step S1, zinc ions are adsorbed onto the surface of mica powder through electrostatic interaction and complexation. Subsequently, a phosphate solution is added dropwise, using the zinc ions adsorbed on the mica powder surface as nucleation sites to generate insoluble zinc phosphate. This overcomes the defect of traditional coatings where simple physical mixing of mica powder and zinc phosphate powder easily leads to severe agglomeration. The two-dimensional large aspect ratio of mica powder provides an excellent physical shielding (maze) effect, blocking the penetration of water and oxygen. Meanwhile, the zinc phosphate attached to it imparts chemical anti-corrosion function. When trace amounts of corrosive media penetrate, the phosphate ions dissociated from zinc phosphate can react with the underlying metal to form a dense iron phosphate passivation film, improving the anti-corrosion performance of the coating.

[0012] Specifically, in step S2, the mass ratio of zinc phosphate / mica powder material to tetraethyl orthosilicate is 10:1-2.

[0013] In step S2, a silica coating layer is constructed on the outer layer of the zinc phosphate / mica powder material, which further enhances the physical shielding effect and coats the zinc phosphate to prevent it from dissolving and failing prematurely during coating application. Furthermore, the introduction of the silica coating layer can provide a large number of polar silanol groups, providing sufficient chemical anchoring points for the subsequent introduction of coupling agents.

[0014] Specifically, in step S3, the mass ratio of the composite filler to 3-(trimethoxysilyl)propyl methacrylate is 10-15:0.5-1.

[0015] In step S3, the introduction of carbon-carbon double bonds facilitates the subsequent reaction.

[0016] Specifically, in step S4, the mass ratio of the double bond grafted composite filler, dodecafluoroheptyl methacrylate, hydroxyethyl methacrylate, and benzoyl peroxide is 10-15:3-6:2-4:0.2-0.5.

[0017] Specifically, in step S4, the temperature for heating and stirring the reaction is 70-85℃, for example, 70℃, 75℃, 80℃, or 85℃ can be selected; the time for heating and stirring the reaction is 3-6h, for example, 3h, 4h, 5h, or 6h can be selected, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0018] In step S4, dodecyl fluoroheptyl methacrylate and hydroxyethyl methacrylate copolymerize and are grafted onto the surface of the composite filler. The dense fluorine atoms in the side chains of dodecyl fluoroheptyl methacrylate endow the filler with excellent hydrophobicity, which, together with the physical shielding effect of the composite filler, prevents the penetration of moisture and chloride ions from the source. Hydroxyethyl methacrylate provides active hydroxyl groups. During the coating curing stage, these side chain hydroxyl groups act as "crosslinking sites" and directly participate in the curing crosslinking network of epoxy resin and polyamide. The composite filler is introduced into the resin skeleton through covalent bonds, which increases the crosslinking density and further improves the anti-corrosion performance of the coating. Moreover, when subjected to external tensile force, the stress can be uniformly transmitted, avoiding microcracks and peeling at the filler / resin interface and improving the adhesion of the coating.

[0019] In the technical solution disclosed in this invention, the dispersant can make pigment particles uniformly dispersed, while preventing inorganic particles from settling and agglomerating. The weight parts of the dispersant can be selected as 1 part, 2 parts, 3 parts, 4 parts, or 5 parts, but are not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] In the technical solution disclosed in this invention, the dispersant is selected from BYK-190, BYK-192 or BYK-194.

[0021] In the technical solution disclosed in this invention, the defoamer can effectively destroy the bubble wall and quickly discharge it from the system, preventing defects such as pinholes and fish eyes from forming after drying and film formation. The weight parts of the defoamer can be selected as 0.5 parts, 1 part, 1.5 parts, or 2 parts, but are not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] In the technical solution disclosed in this invention, the defoamer is selected from the defoamer with the trade code PA311 from Ota Chemical.

[0023] In the technical solution disclosed in this invention, the leveling agent can reduce the surface tension of the system, promote better flow and spread of the coating liquid, and eliminate surface defects such as brush marks and orange peel. The weight parts of the leveling agent can be selected as 0.2 parts, 0.3 parts, 0.4 parts, or 0.5 parts, but are not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] In the technical solution disclosed in this invention, the leveling agent is selected from siloxane leveling agents.

[0025] In the technical solution disclosed in this invention, the weight parts of deionized water can be selected as 40 parts, 45 parts, 50 parts, 55 parts, or 60 parts, but are not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0026] In the technical solution disclosed in this invention, the mass ratio of component A to component B is 4-8:1. For example, 4:1, 5:1, 6:1, 7:1, and 8:1 can be selected, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0027] The present invention also provides an anti-corrosion coating for metal protection prepared by the above preparation method.

[0028] Compared with the prior art, the present invention has the following beneficial effects: (1) The anti-corrosion coating provided by the present invention introduces organosilicon-modified epoxy resin, which effectively releases the residual internal stress generated during the high cross-linking and curing of the resin by utilizing its flexible siloxane segments. This significantly improves the defects of traditional epoxy coatings, which are rigid and brittle. At the same time, it gives the coating surface good hydrophobic properties. The composite modified filler effectively eliminates the micropores caused by filler agglomeration through physical shielding effect, chemical anti-corrosion function of zinc phosphate and synergistic effect of interfacial covalent cross-linking between polar groups and resin. This improves the anti-corrosion performance and adhesion of the coating and achieves long-term comprehensive protection for metal substrates.

[0029] (2) The composite modified filler provided by the present invention adsorbs zinc ions onto the surface of mica powder through electrostatic action and complexation. Then, phosphate solution is added dropwise, and the zinc ions adsorbed on the surface of mica powder serve as nucleation points to generate insoluble zinc phosphate. This changes the defect of traditional coatings where simple physical mixing of mica powder and zinc phosphate powder easily leads to severe agglomeration. The two-dimensional large aspect ratio of mica powder provides an excellent physical shielding (maze) effect, blocking the penetration of water and oxygen. The zinc phosphate attached to it gives chemical anti-corrosion function. When a trace amount of corrosive medium penetrates, the phosphate ions dissociated from zinc phosphate can react with the underlying metal to form a dense iron phosphate passivation film, which improves the anti-corrosion performance of the coating.

[0030] (3) The composite modified filler provided by the present invention is obtained by copolymerizing dodecyl fluoroheptyl methacrylate and hydroxyethyl methacrylate on the surface of the composite filler. The dense fluorine atoms in the side chain of dodecyl fluoroheptyl methacrylate endow the filler with excellent hydrophobicity, which, together with the physical shielding effect of the composite filler, prevents the penetration of water and chloride ions from the source. Hydroxyethyl methacrylate provides active hydroxyl groups. During the curing stage of the coating, these side chain hydroxyl groups will act as "crosslinking sites" and directly participate in the curing crosslinking network of epoxy resin and polyamide. The composite filler is introduced into the resin skeleton through covalent bonds, which increases the crosslinking density and further improves the anti-corrosion performance of the coating. Moreover, when subjected to external force, the stress can be uniformly transmitted, avoiding microcracks and peeling at the filler / resin interface and improving the adhesion of the coating. Detailed Implementation

[0031] The present invention will be further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0032] It should be noted that, unless otherwise specified, all chemical reagents involved in this invention were purchased through commercial channels.

[0033] The epoxy resin used in this embodiment of the invention is EP-260 water-dispersible epoxy resin from Jiangsu Shisong New Material Technology Co., Ltd.; the silicone-modified epoxy resin is TY-H26; the mica powder has a mesh size of 200 mesh; the dispersant is selected from dispersant BYK-190; the leveling agent is selected from leveling agent 4333 from Shanghai Shenzhu Chemical Additives Co., Ltd.; the defoamer is selected from defoamer with trade code PA311 from Datian Chemical; and the polyamide curing agent is polyamide curing agent 650.

[0034] Example 1 A method for preparing an anti-corrosion coating for metal protection includes the following steps: 80 parts of epoxy resin and 10 parts of silicone-modified epoxy resin are injected into a mixing tank equipped with a stirrer, and the stirrer is started at a speed of 400 r / min. Then, 40 parts of deionized water, 1 part of dispersant, and 20 parts of composite modified filler are added sequentially and stirred evenly. Subsequently, the mixture is ground and dispersed using a sand mill until the fineness meets the requirements for film formation. Then, 0.5 parts of defoamer and 0.2 parts of leveling agent are added and dispersed evenly to obtain component A. Component A and polyamide curing agent are stored separately for later use.

[0035] The preparation method of the composite modified filler is as follows: S1. Disperse 10g of mica powder in 150mL of deionized water, then add 1g of zinc nitrate hexahydrate to it, stir and adsorb for 2h, then add 15g of 5wt% phosphate solution dropwise while stirring, at a dropping rate of 2 drops / s, and after the addition is completed, age for 6h, filter, wash and dry to obtain zinc phosphate / mica powder material. S2. Disperse 10g of zinc phosphate / mica powder material in 150mL of 80wt% ethanol aqueous solution, adjust the pH of the solution to 7.0 with acetic acid-ammonia buffer system, then add 1g of tetraethyl orthosilicate, stir for 2h, age for 12h, filter, wash and dry to obtain composite filler; S3. Disperse 10g of composite filler in 150mL of 80wt% ethanol aqueous solution, then add 0.5g of 3-(trimethoxysilyl)methacrylate, stir at room temperature for 2h, filter, wash and dry to obtain double bond grafted composite filler. S4. Disperse 10g of double bond grafted composite filler in 150mL of organic solvent DMF, then add 3g of dodecafluoroheptyl methacrylate and 2g of hydroxyethyl methacrylate, stir evenly, then add 0.2g of initiator benzoyl peroxide, heat and stir at 75℃ for 4h under nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain composite modified filler.

[0036] Example 2 A method for preparing an anti-corrosion coating for metal protection includes the following steps: 100 parts of epoxy resin and 20 parts of silicone-modified epoxy resin are injected into a mixing tank equipped with a stirrer, and stirring is started at a speed of 400 r / min. Then, 60 parts of deionized water, 5 parts of dispersant, and 40 parts of composite modified filler are added sequentially and stirred evenly. Subsequently, the mixture is ground and dispersed using a sand mill until the fineness meets the requirements for film formation. Then, 2 parts of defoamer and 0.5 parts of leveling agent are added and dispersed evenly to obtain component A. Component A and polyamide curing agent are stored separately for later use.

[0037] The preparation method of the composite modified filler is as follows: S1. Disperse 10g of mica powder in 150mL of deionized water, then add 3g of zinc nitrate hexahydrate to it, stir and adsorb for 2h, then add 25g of 5wt% phosphate solution dropwise while stirring, at a dropping rate of 2 drops / s, and after the addition is completed, age for 6h, filter, wash and dry to obtain zinc phosphate / mica powder material. S2. Disperse 10g of zinc phosphate / mica powder material in 150mL of 80wt% ethanol aqueous solution, adjust the pH of the solution to 7.0 with acetic acid-ammonia buffer system, then add 2g of tetraethyl orthosilicate, stir for 2h, age for 12h, filter, wash and dry to obtain composite filler; S3. Disperse 10g of composite filler in 150mL of 80wt% ethanol aqueous solution, then add 1g of 3-(trimethoxysilyl)methacrylate, stir at room temperature for 2h, filter, wash and dry to obtain double bond grafted composite filler. S4. Disperse 10g of double bond grafted composite filler in 150mL of organic solvent DMF, then add 6g of dodecafluoroheptyl methacrylate and 4g of hydroxyethyl methacrylate, stir evenly, then add 0.5g of initiator benzoyl peroxide, heat and stir at 85℃ for 3h under nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain composite modified filler.

[0038] Example 3 A method for preparing an anti-corrosion coating for metal protection includes the following steps: 90 parts of epoxy resin and 15 parts of silicone-modified epoxy resin are injected into a mixing tank equipped with a stirrer, and stirring is started at a speed of 400 r / min. Then, 50 parts of deionized water, 3 parts of dispersant, and 30 parts of composite modified filler are added sequentially and stirred evenly. Subsequently, the mixture is ground and dispersed using a sand mill until the fineness meets the requirements for film formation. Then, 1 part of defoamer and 0.3 parts of leveling agent are added and dispersed evenly to obtain component A. Component A and polyamide curing agent are stored separately for later use.

[0039] The preparation method of the composite modified filler is as follows: S1. Disperse 10g of mica powder in 150mL of deionized water, then add 2g of zinc nitrate hexahydrate to it, stir and adsorb for 2h, then add 20g of 5wt% phosphate solution dropwise while stirring, at a rate of 2 drops / s, and after the addition is completed, age for 6h, filter, wash and dry to obtain zinc phosphate / mica powder material. S2. Disperse 10g of zinc phosphate / mica powder material in 150mL of 80wt% ethanol aqueous solution, adjust the pH of the solution to 7.0 with acetic acid-ammonia buffer system, then add 1.5g of tetraethyl orthosilicate, stir for 2h, age for 12h, filter, wash and dry to obtain composite filler; S3. Disperse 10g of composite filler in 150mL of 80wt% ethanol aqueous solution, then add 0.8g of 3-(trimethoxysilyl)methacrylate, stir at room temperature for 2h, filter, wash and dry to obtain double bond grafted composite filler. S4. Disperse 10g of double bond grafted composite filler in 150mL of organic solvent DMF, then add 5g of dodecafluoroheptyl methacrylate and 3g of hydroxyethyl methacrylate, stir evenly, then add 0.3g of initiator benzoyl peroxide, heat and stir at 85℃ for 3h under nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain composite modified filler.

[0040] Comparative Example 1 A method for preparing an anti-corrosion coating for metal protection includes the following steps: 80 parts of epoxy resin and 10 parts of silicone-modified epoxy resin are injected into a mixing tank equipped with a stirrer, and the stirrer is started at a speed of 400 r / min. Then, 40 parts of deionized water, 1 part of dispersant, and 20 parts of composite modified filler are added sequentially and stirred evenly. Subsequently, the mixture is ground and dispersed using a sand mill until the fineness meets the requirements for film formation. Then, 0.5 parts of defoamer and 0.2 parts of leveling agent are added and dispersed evenly to obtain component A. Component A and polyamide curing agent are stored separately for later use.

[0041] The preparation method of the composite modified filler is as follows: S1. Disperse 10g of mica powder in 150mL of 80wt% ethanol aqueous solution, adjust the pH of the solution to 7.0 with acetic acid-ammonia buffer system, then add 1g of tetraethyl orthosilicate, stir for 2h, age for 12h, filter, wash and dry to obtain composite filler. S2. Disperse 10g of composite filler in 150mL of 80wt% ethanol aqueous solution, then add 0.5g of 3-(trimethoxysilyl)methacrylate, stir at room temperature for 2h, filter, wash and dry to obtain double bond grafted composite filler. S3. Disperse 10g of double bond grafted composite filler in 150mL of organic solvent DMF, then add 3g of dodecafluoroheptyl methacrylate and 2g of hydroxyethyl methacrylate, stir evenly, then add 0.2g of initiator benzoyl peroxide, heat and stir at 75℃ for 4h under nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain composite modified filler.

[0042] Compared to Comparative Example 1 and Example 1, the mica powder was not loaded with zinc phosphate.

[0043] Comparative Example 2 A method for preparing an anti-corrosion coating for metal protection includes the following steps: 80 parts of epoxy resin and 10 parts of silicone-modified epoxy resin are injected into a mixing tank equipped with a stirrer, and the stirrer is started at a speed of 400 r / min. Then, 40 parts of deionized water, 1 part of dispersant, and 20 parts of composite modified filler are added sequentially and stirred evenly. Subsequently, the mixture is ground and dispersed using a sand mill until the fineness meets the requirements for film formation. Then, 0.5 parts of defoamer and 0.2 parts of leveling agent are added and dispersed evenly to obtain component A. Component A and polyamide curing agent are stored separately for later use.

[0044] The preparation method of the composite modified filler is as follows: S1. Disperse 10g of mica powder in 150mL of deionized water, then add 1g of zinc nitrate hexahydrate and stir for 2h for adsorption. Then, while stirring, add 15g of 5wt% phosphate solution at a rate of 2 drops / s. After the addition is completed, let it age for 6h, then filter, wash and dry to obtain the composite filler. S2. Disperse 10g of composite filler in 150mL of 80wt% ethanol aqueous solution, then add 0.5g of 3-(trimethoxysilyl)methacrylate, stir at room temperature for 2h, filter, wash and dry to obtain double bond grafted composite filler. S3. Disperse 10g of double bond grafted composite filler in 150mL of organic solvent DMF, then add 3g of dodecafluoroheptyl methacrylate and 2g of hydroxyethyl methacrylate, stir evenly, then add 0.2g of initiator benzoyl peroxide, heat and stir at 75℃ for 4h under nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain composite modified filler.

[0045] Compared to Comparative Example 2 and Example 1, no silica was loaded on the composite filler.

[0046] Comparative Example 3 A method for preparing an anti-corrosion coating for metal protection includes the following steps: 80 parts of epoxy resin and 10 parts of silicone-modified epoxy resin are injected into a mixing tank equipped with a stirrer, and the stirrer is started at a speed of 400 r / min. Then, 40 parts of deionized water, 1 part of dispersant, and 20 parts of composite modified filler are added sequentially and stirred evenly. Subsequently, the mixture is ground and dispersed using a sand mill until the fineness meets the requirements for film formation. Then, 0.5 parts of defoamer and 0.2 parts of leveling agent are added and dispersed evenly to obtain component A. Component A and polyamide curing agent are stored separately for later use.

[0047] The preparation method of the composite modified filler is as follows: S1. Disperse 10g of mica powder in 150mL of deionized water, then add 1g of zinc nitrate hexahydrate to it, stir and adsorb for 2h, then add 15g of 5wt% phosphate solution dropwise while stirring, at a dropping rate of 2 drops / s, and after the addition is completed, age for 6h, filter, wash and dry to obtain zinc phosphate / mica powder material. S2. Disperse 10g of zinc phosphate / mica powder material in 150mL of 80wt% ethanol aqueous solution, adjust the pH of the solution to 7.0 with acetic acid-ammonia buffer system, then add 1g of tetraethyl orthosilicate, stir for 2h, age for 12h, filter, wash and dry to obtain composite filler; S3. Disperse 10g of composite filler in 150mL of 80wt% ethanol aqueous solution, then add 0.5g of 3-(trimethoxysilyl)methacrylate, stir at room temperature for 2h, filter, wash and dry to obtain double bond grafted composite filler. S4. Disperse 10g of double bond grafted composite filler in 150mL of organic solvent DMF, then add 3g of dodecafluoroheptyl methacrylate and stir evenly. Then add 0.2g of initiator benzoyl peroxide and heat and stir at 75℃ for 4h under nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain composite modified filler.

[0048] Compared with Example 1, Comparative Example 3 did not introduce hydroxyethyl methacrylate.

[0049] Comparative Example 4 A method for preparing an anti-corrosion coating for metal protection includes the following steps: 80 parts of epoxy resin and 10 parts of silicone-modified epoxy resin are injected into a mixing tank equipped with a stirrer. The stirrer is started at a speed of 400 r / min. Then, 40 parts of deionized water, 1 part of dispersant, 15 parts of mica powder, 2.5 parts of zinc phosphate, and 2.5 parts of nano-silica are added sequentially and stirred until homogeneous. The mixture is then ground and dispersed using a sand mill until the fineness meets the film-forming requirements. Next, 0.5 parts of defoamer and 0.2 parts of leveling agent are added and dispersed until homogeneous, thus obtaining component A. Component A and the polyamide curing agent are stored separately for later use.

[0050] Compared with Example 1, Comparative Example 4 directly physical blends mica powder, zinc phosphate and nano silica.

[0051] The A component prepared in Examples 1-3 and Comparative Examples 1-4 and the polyamide curing agent were mixed evenly at a mass ratio of 5:1, and then sprayed onto the surface of a 5mm thick sandblasted steel plate with a spray thickness of 200μm. The mixture was cured and crosslinked at 65℃ for 4h, and then the performance was tested.

[0052] Adhesion test: The test was conducted in accordance with GB / T 5210-2006 "Paints and Varnishes - Pull-off test". Neutral salt spray test: The test method refers to GB / T 10125-2012. The corrosion resistance of the sample is evaluated by observing the time it takes for white rust to appear on the steel plate. Salt water resistance test: The coated steel plates were immersed in a 3.5% sodium chloride solution, and the corrosion resistance of the samples was evaluated by observing the time it took for white rust to appear. The test results are shown in Table 1.

[0053] Table 1 Performance test results for different groups

[0054] Finally, it should be noted that the above embodiments do not limit the present invention in any way. Those skilled in the art can make modifications and improvements based on the present invention. Therefore, any modifications or improvements made without departing from the spirit of the present invention are within the scope of protection claimed by the present invention.

Claims

1. An anti-corrosion coating for metal protection, comprising component A and component B, characterized in that, By weight, component A comprises the following raw materials: 80-100 parts epoxy resin, 10-20 parts silicone-modified epoxy resin, 20-40 parts composite modified filler, 1-5 parts dispersant, 0.5-2 parts defoamer, 0.2-0.5 parts leveling agent, and 40-60 parts deionized water; component B is a polyamide curing agent.

2. The anti-corrosion coating according to claim 1, characterized in that, The mass ratio of component A to component B is 4-8:

1.

3. The anti-corrosion coating according to claim 1, characterized in that, The preparation method of the composite modified filler is as follows: S1. Disperse mica powder in deionized water, then add soluble zinc salt and stir to adsorb. Then, while stirring, add phosphate solution dropwise. After the addition is completed, age the solution, filter, wash and dry to obtain zinc phosphate / mica powder material. S2. Disperse zinc phosphate / mica powder material in an ethanol aqueous solution, adjust the pH of the solution to 6.8-7.2 using an acetic acid-ammonia buffer system, then add tetraethyl orthosilicate, stir, and after aging, filtration, washing, and drying, obtain the composite filler. S3. Disperse the composite filler in an ethanol aqueous solution, then add 3-(trimethoxysilyl)propyl methacrylate, stir, filter, wash and dry to obtain the double bond grafted composite filler. S4. Disperse the double bond grafted composite filler in an organic solvent, then add dodecafluoroheptyl methacrylate and hydroxyethyl methacrylate to it, stir evenly, then add the initiator benzoyl peroxide, heat and stir the reaction under a nitrogen atmosphere, and after the reaction is completed, filter, wash and dry to obtain the composite modified filler.

4. The anti-corrosion coating according to claim 3, characterized in that, In step S1, the mass ratio of mica powder, soluble zinc salt, and phosphate solution is 10:1-3:15-25, and the mass fraction of phosphate solution is 5-10%.

5. The anti-corrosion coating according to claim 3, characterized in that, In step S2, the mass ratio of zinc phosphate / mica powder material to tetraethyl orthosilicate is 10:1-2.

6. The anti-corrosion coating according to claim 3, characterized in that, In step S3, the mass ratio of the composite filler to propyl 3-(trimethoxysilyl)methacrylate is 10-15:0.5-1.

7. The anti-corrosion coating according to claim 3, characterized in that, In step S4, the mass ratio of the double bond grafted composite filler, dodecafluoroheptyl methacrylate, hydroxyethyl methacrylate, and benzoyl peroxide is 10-15:3-6:2-4:0.2-0.

5.

8. The anti-corrosion coating according to claim 3, characterized in that, In step S4, the temperature for heating and stirring the reaction is 70-85℃, and the reaction time is 3-6 hours.

9. The method for preparing the anti-corrosion coating according to any one of claims 1-8, characterized in that, The process includes the following steps: inject epoxy resin and silicone-modified epoxy resin into a mixing tank with a stirrer, start stirring, then add deionized water, dispersant and composite modified filler in sequence, stir evenly, then grind and disperse with a sand mill until the fineness meets the film-forming requirements, then add defoamer and leveling agent, disperse evenly, and obtain component A; store component A and component B separately for later use.

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