A metal anticorrosive coating and a method for preparing the same

Abstract

The present application relates to a kind of metal anticorrosive coating and its preparation method, belong to the field of coating technology, with excellent hydrophobicity, high adhesion and corrosion resistance and other advantages.The coating includes A component and B component, wherein A component includes fluorocarbon resin, modified polyurea compound, fluorine-containing silane modified silica, anti-flash rust agent, defoaming agent, wetting agent, leveling agent and organic solvent;B component includes curing agent and organic solvent.Modified polyurea compound is prepared by 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane and 4,4'-difluorobenzophenone polycondensation, then reacted with isophorone diisocyanate, C-F bond and polyether ether ketone structure are introduced, the compatibility with fluorocarbon resin and coating adhesion are improved.Fluorine-containing silane modified silica enhances the hydrophobicity and mechanical properties of coating.The coating of the present application can be applied to metal tank body interior protection, and building, cross-sea bridge, ship and other places that are long-term rain erosion and seawater corrosion.

Description

Technical Field

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

[0002] Organic protective coatings have become an effective strategy for solving wear and corrosion problems of materials, metal parts, and machinery in various industries due to their ease of application, high protective efficiency, and cost-effectiveness. Commonly used organic coatings include polyurethane, acrylic, silicone, epoxy resin, and fluorocarbon resin. Among them, fluorocarbon resin coatings are widely used in the field of protective coatings due to their excellent wear resistance, corrosion resistance, weather resistance, and stain resistance. However, fluorocarbon resin coatings have poor adhesion to metal substrates and are prone to cracking or peeling under harsh working conditions, leading to wear and corrosion and severely weakening their protective performance. In addition, the CF bonds on the surface of fluorocarbon resins result in low surface reactivity and poor compatibility with other polymer materials, which also limits the wider application of fluorocarbon resins in the coating field.

[0003] Polymer modification and nanofiller modification are two important approaches to achieving high performance in polymer composites. To improve the corrosion resistance and durability of fluorocarbon resin coatings, modification research has received considerable attention in recent years. Selecting suitable polymers and nanofillers for modification is considered a way to comprehensively improve the overall performance of organic coatings. However, poor compatibility between polymers and resins, and between nanofillers and resins, often limits the improvement of coating performance. Summary of the Invention

[0004] In view of the shortcomings of existing fluorocarbon resin coatings, such as poor adhesion to metal substrates and weak corrosion resistance, this invention provides a metal anti-corrosion coating with excellent hydrophobicity, high adhesion and corrosion resistance.

[0005] The objective of this invention can be achieved through the following technical solution: This invention provides a metal anti-corrosion coating, comprising component A and component B, wherein component A comprises the following components by weight: 70-100 parts of fluorocarbon resin, 5-50 parts of modified polyurea compound, 3-8 parts of fluorinated silane modified silica, 3-5 parts of anti-flash rust agent, 0.1-0.3 parts of defoamer, 0.5-0.7 parts of wetting agent, 0.4-0.8 parts of leveling agent, and 60-80 parts of organic solvent; component B comprises the following components by weight: 15-20 parts of curing agent and 15-20 parts of organic solvent.

[0006] Furthermore, the mass ratio of the fluorocarbon resin to the modified polyurea compound is 10:2-3.

[0007] Furthermore, the organic solvent is one or more of xylene, butyl acetate, propylene glycol methyl ether acetate, and ethylene glycol ethyl ether acetate.

[0008] Furthermore, the curing agent is triglycidyl isocyanurate or biuret polyisocyanate.

[0009] Furthermore, the flash rust inhibitor is any one of the following: organic amine flash rust inhibitor, phosphate flash rust inhibitor, silicate flash rust inhibitor, organic zinc salt flash rust inhibitor, and organic calcium salt flash rust inhibitor.

[0010] Furthermore, the leveling agent is one or more of BYK-348, BYK-3455, and BYK3410.

[0011] Furthermore, the defoamer is one or more of TEGO845, Tego Airex 902W, or TEGO Foamex1488.

[0012] Furthermore, the wetting agent is one or more of TEGO Wet 280, TEGO Wet 270, or BYK-333.

[0013] Furthermore, the preparation process of the modified polyurea compound includes the following steps:

[0014] S1. Under high-purity nitrogen protection, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 4,4′-difluorobenzophenone, anhydrous K2CO3, tetramethylene sulfone, and toluene were added to a three-necked flask to form a mixture. The reaction mixture was continuously stirred and heated at 120°C for 2 hours, then the reaction temperature was raised to 230°C and the reaction was continued for 3 hours. After cooling to room temperature, the product was precipitated at room temperature by adding distilled water under nitrogen protection. Finally, it was dried under vacuum to obtain intermediate 1. The ratio of the amounts of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 4,4′-difluorobenzophenone, anhydrous K2CO3, tetramethylene sulfone, and toluene was 140 g: 84 g: 25 g: 200 mL: 100 mL.

[0015] Under the catalysis of potassium carbonate, the phenolic hydroxyl group in 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and the fluorinated aromatic hydrocarbon on 4,4′-difluorobenzophenone undergo a condensation reaction to obtain intermediate 1 with a polyether ether ketone structure; the specific reaction process is shown below:

[0016]

[0017] S2. Dissolve intermediate 1 in tetrahydrofuran, and slowly add isophorone diisocyanate dropwise while stirring at room temperature for 0.5 hours. After stirring at room temperature for 3 hours, purify and wash, and dry under vacuum to obtain the modified polyurea compound. The ratio of intermediate 1, IPDI and tetrahydrofuran is 60g:19g:200mL.

[0018] The amino groups in intermediate 1 further react with the isocyanate groups in IPDI to generate a modified polyurea compound with a polyether ether ketone structure; the specific reaction process is shown below:

[0019]

[0020] The modified polyurea compound prepared by the above-mentioned specific preparation process of this invention introduces CF bonds into the resin, which improves its compatibility with fluorocarbon resin. At the same time, the resin contains a large number of polyether ether ketone bonds and urea bonds, which improves the adhesion, heat resistance, weather resistance and flexibility of the coating film. In addition, the isocyanate bonds in the modified polyurea compound can also participate in the curing process of fluorocarbon resin, further improving the compatibility and crosslinking density of the system, thereby achieving durable performance.

[0021] The present invention also provides a method for preparing a metal anti-corrosion coating, the specific preparation steps of which are as follows: S1, preparation of component A: weigh the raw material of component A in the formula amount, mix the fluorocarbon resin and organic solvent evenly, and add the fluorosilane modified silica filler, anti-flash rust agent, defoamer, wetting agent and leveling agent in sequence under stirring, and stir thoroughly;

[0022] Preparation of components S2 and B: Mix the prescribed amount of curing agent with the organic solvent evenly;

[0023] S3. Preparation of metal anti-corrosion coating: Add component B to component A and stir to mix evenly to obtain the metal anti-corrosion coating.

[0024] Compared with the prior art, the present invention has the following advantages and technical effects:

[0025] This invention relates to a modified polyurea compound prepared using a specific process and added to a coating based on fluorocarbon resin. By adjusting the relative amounts of fluorocarbon resin and modified polyurea compound, the coating exhibits good adhesion, acid and alkali resistance, and salt spray resistance within a specific ratio range. An appropriate amount of modified polyurea resin can improve the film-forming properties of fluorocarbon resin and its adhesion to the substrate, thereby enhancing corrosion resistance in practical applications after film formation. In addition, the addition of fluorinated silane-modified silica particles improves the dispersibility of nanoparticles and their compatibility with the resin matrix. Besides increasing the hardness and mechanical properties of the coating, the nano-silica particles form a special "micro-nano" structure in the system, further enhancing hydrophobicity and giving the coating a superhydrophobic effect. Detailed Implementation

[0026] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0027] The main products used in the following embodiments are as follows: fluorocarbon resin is HLR-6; organic solvent is a mixture of xylene and propylene glycol methyl ether acetate; anti-flash rust agent is an organic amine anti-flash rust agent; leveling agent is BYK-348; defoamer is TEGO845; wetting agent is BYK-333; curing agent is triglycidyl isocyanurate.

[0028] Example 1

[0029] This embodiment provides a metal anti-corrosion coating and its preparation method. The metal anti-corrosion coating comprises the following raw materials by weight: component A and component B. Component A comprises the following components by weight: 100 parts of fluorocarbon resin, 20 parts of modified polyurea compound, 3 parts of fluorinated silane modified silica filler, 3 parts of anti-flash rust agent, 0.1 parts of defoamer, 0.5 parts of wetting agent, 0.4 parts of leveling agent, and 80 parts of organic solvent. Component B comprises the following components by weight: 15 parts of curing agent and 20 parts of organic solvent.

[0030] The modified polyurea compound was prepared by the following method: S1. Under high-purity nitrogen protection, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 4,4′-difluorobenzophenone, anhydrous K2CO3, tetramethylene sulfone, and toluene were added to a three-necked flask to form a mixture. The reaction mixture was continuously stirred and heated at 120°C for 2 hours, and then the reaction temperature was raised to 230°C and the reaction was continued for 3 hours. After cooling to room temperature, the product was precipitated at room temperature by adding distilled water under nitrogen protection. Finally, it was dried under vacuum to obtain intermediate 1. The ratio of the amounts of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 4,4′-difluorobenzophenone, anhydrous K2CO3, tetramethylene sulfone, and toluene was 140 g: 84 g: 25 g: 200 mL: 100 mL.

[0031] S2. Dissolve intermediate 1 in tetrahydrofuran, and slowly add IPDI solution dropwise while stirring at room temperature for 0.5 hours. After stirring at room temperature for 3 hours, purify and wash, and dry under vacuum to obtain the modified polyurea compound. The ratio of intermediate 1, IPDI and tetrahydrofuran is 60g:19g:200mL.

[0032] The fluorinated silane-modified silica filler was prepared by the following method: nano silica, perfluorooctyltrioxane and deionized water were mixed in a ball mill for 2 hours and then vacuum dried overnight at 75-85°C to obtain fluorinated silane-modified silica; the ratio of nano silica, perfluorooctyltrioxane and deionized water was 5g:0.5g:60mL.

[0033] The specific preparation method of the metal anti-corrosion coating is as follows: S1, Preparation of component A: Weigh the raw material of component A in the formula amount, mix the fluorocarbon resin and organic solvent evenly, and add the fluorosilane modified silica filler, anti-flash rust agent, defoamer, wetting agent and leveling agent in sequence while stirring, and stir thoroughly;

[0034] Preparation of components S2 and B: Mix the prescribed amount of curing agent with the organic solvent evenly;

[0035] S3. Preparation of metal anti-corrosion coating: Add component B to component A and stir to mix evenly to obtain the metal anti-corrosion coating.

[0036] Example 2

[0037] This embodiment provides a metal anti-corrosion coating and its preparation method. Compared with Embodiment 1, Embodiment 2 differs in that the modified polyurea compound is 30 parts by weight, that is, the weight ratio of fluorocarbon resin to modified polyurea compound is 10:3.

[0038] Comparative Example 1

[0039] Compared with Example 1, Comparative Example 1 differs in that the modified polyurea compound is 10 parts by weight, that is, the weight ratio of fluorocarbon resin to modified polyurea compound is 10:1, while the other components, preparation steps and parameters are the same.

[0040] Comparative Example 2

[0041] Compared with Example 1, Comparative Example 2 differs in that the modified polyurea compound is 40 parts by weight, that is, the weight ratio of fluorocarbon resin to modified polyurea compound is 10:4, while the other components, preparation steps and parameters are the same.

[0042] Comparative Example 3

[0043] Compared with Example 1, Comparative Example 3 differs in that no component-modified polyurea compound is added, while the other components, preparation steps and parameters are the same.

[0044] The above-described examples and comparative examples of coating samples were coated onto cleaned tinplate specimens for performance testing. After curing at room temperature for 5-7 hours and at 25°C for 14 days, the coatings were subjected to the following performance tests. The test results are shown in Table 1.

[0045] The relevant testing standards are as follows: adhesion test according to GB / T 9286-2021, 240h acid, alkali and salt resistance test according to GB / T 9274-1988, and 4000h neutral salt spray resistance test according to GB / T 1771-2007.

[0046] Table 1

[0047]

[0048] As can be seen from the test results in Table 1, compared with Comparative Examples 1-3, the addition of modified polyurea compounds to the coatings based on fluorocarbon resin in Examples 1-2, and by adjusting the relative amounts of fluorocarbon resin and modified polyurea compounds, showed that the coatings exhibited good adhesion, acid and alkali resistance, and salt spray resistance within a specific dosage range. This is because an appropriate amount of modified polyurea resin can improve the film-forming properties of fluorocarbon resin and its adhesion to the substrate, thereby improving corrosion resistance in actual applications after film formation.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any indirect modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A metal anti-corrosion coating, characterized in that, The product comprises component A and component B, wherein component A contains the following components by weight: 70-100 parts fluorocarbon resin, 5-50 parts modified polyurea compound, 3-8 parts fluorosilane-modified silica, 3-5 parts anti-flash rust agent, 0.1-0.3 parts defoamer, 0.5-0.7 parts wetting agent, 0.4-0.8 parts leveling agent, and 60-80 parts organic solvent; component B contains the following components by weight: 15-20 parts curing agent and 15-20 parts organic solvent. The preparation process of the modified polyurea compound includes the following steps: S1. Under high-purity nitrogen protection, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 4,4′-difluorobenzophenone, anhydrous K2CO3, tetramethylene sulfone, and toluene were added to a three-necked flask to form a mixture. The reaction mixture was continuously stirred and heated at 120°C for 2 hours, then the reaction temperature was raised to 230°C and the reaction was continued for 3 hours. After cooling to room temperature, the product was precipitated at room temperature by adding distilled water under nitrogen protection. Finally, it was dried under vacuum to obtain the intermediate. The ratio of the amounts of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 4,4′-difluorobenzophenone, anhydrous K2CO3, tetramethylene sulfone, and toluene was 140 g: 84 g: 25 g: 200 mL: 100 mL. S2. Dissolve the intermediate in tetrahydrofuran, and slowly add isophorone diisocyanate dropwise while stirring at room temperature for 0.5 hours. After stirring at room temperature for 3 hours, purify and wash, and dry under vacuum to obtain the modified polyurea compound. The ratio of the amount of intermediate, isophorone diisocyanate and tetrahydrofuran is 60g:19g:200mL. The curing agent is triglycidyl isocyanurate or biuret polyisocyanate; The flash rust inhibitor is any one of organic amine flash rust inhibitors, phosphate flash rust inhibitors, silicate flash rust inhibitors, organic zinc salt flash rust inhibitors, and organic calcium salt flash rust inhibitors.

2. The metal anti-corrosion coating according to claim 1, characterized in that, The mass ratio of the fluorocarbon resin to the modified polyurea compound is 10:2-3.

3. The metal anti-corrosion coating according to claim 1, characterized in that, The leveling agent is one or more of BYK-348, BYK-3455, and BYK-3410; And / or, the defoamer is one or more of TEGO845, Tego Airex 902W or TEGO Foamex1488; And / or, the wetting agent is one or more of TEGO Wet 280, TEGO Wet 270 or BYK-333; And / or, the organic solvent is one or more of xylene, butyl acetate, propylene glycol methyl ether acetate, and ethylene glycol ethyl ether acetate.

4. A method for preparing a metal anti-corrosion coating as described in any one of claims 1-3, the method comprising the following steps: S1, preparation of component A: weighing the raw material of component A in the formula amount, mixing the fluorocarbon resin and organic solvent evenly, and adding fluorosilane-modified silica, anti-flash rust agent, defoamer, wetting agent and leveling agent in sequence under stirring, and stirring thoroughly; Preparation of components S2 and B: Mix the prescribed amount of curing agent with the organic solvent evenly; S3. Preparation of metal anti-corrosion coating: Add component B to component A and stir to mix evenly to obtain the metal anti-corrosion coating.

Images