A high-temperature resistant anti-corrosion coating, its preparation method and application

Abstract

This invention discloses a high-temperature resistant anti-corrosion coating, its preparation method, and its application. The coating, by weight, is prepared from raw materials comprising the following components: 30-50 parts organic-inorganic hybrid resin, 30-45 parts alumina-doped copper chromium black, 10-30 parts deionized water, 5-10 parts acidic aluminum sol, 5-10 parts chromium trioxide, and 0.5-1 parts additives. This invention uses an organic-inorganic hybrid resin as the main film-forming substance, adding alumina-doped copper chromium black and additives to give it excellent flexibility and adhesion, while also being able to withstand high temperatures above 1000℃ and salt spray corrosion.

Description

Technical Field

[0001] This invention relates to the field of special coatings, specifically to a high-temperature resistant anti-corrosion coating, its preparation method, and its application. Background Technology

[0002] High-temperature resistant anti-corrosion coatings generally refer to special functional coatings that do not discolor or peel at 200℃ and above, and enable the protected object to function normally in such high-temperature environments. Coatings with organic substances as the main film-forming material have good toughness, processability, and dielectric properties; however, when the temperature exceeds 300℃, the organic bonds break, leading to aging and severe chalking. Therefore, when the temperature exceeds 300℃, inorganic high-temperature resistant anti-corrosion coatings are recommended.

[0003] Currently, the most widely used inorganic high-temperature resistant anti-corrosion coatings in industry are phosphate and silicate coatings. Phosphate coatings use an aqueous solution of acidic phosphates as the main film-forming substance, and the ratio of metal atoms to phosphorus is a crucial indicator of the coating's performance. Phosphate coatings possess excellent heat resistance, weather resistance, solvent resistance, and high-temperature oxidation resistance, maintaining long-term stability at temperatures ranging from 400 to 1000℃. However, to protect the substrate and pigments, phosphate coatings typically require chromic acid passivation and high-temperature curing, the high curing temperature limiting their application range. Silicate coatings use sodium silicate or potassium silicate as the main film-forming substance, offering advantages such as good temperature resistance and cost-effectiveness. However, silicate coatings have high porosity, and the resin has poor water resistance, making them prone to moisture absorption and dampness in humid environments, significantly reducing adhesion. Therefore, developing a water-based, environmentally friendly, room-temperature curing, high-temperature resistant, and corrosion-resistant high-temperature anti-corrosion coating is of great significance. Summary of the Invention

[0004] To address the problems of organic coatings being unresistant to high temperatures and inorganic coatings having poor adhesion, this invention provides a high-temperature resistant anti-corrosion coating, its preparation method, and its application. This high-temperature resistant anti-corrosion coating combines the rigidity, dimensional stability, and thermal stability of inorganic coatings with the toughness, processability, and dielectric properties of organic coatings, exhibiting excellent temperature resistance and anti-corrosion performance.

[0005] To achieve the above objectives, the present invention provides a high-temperature resistant anti-corrosion coating, which, by weight, is made from raw materials comprising the following components: 30-50 parts of organic-inorganic hybrid resin, 30-45 parts of alumina-doped copper chromium black, 10-30 parts of deionized water, 5-10 parts of acidic aluminum sol, 5-10 parts of chromium trioxide, and 0.5-1 parts of additives.

[0006] The raw materials of this invention incorporate an organic-inorganic hybrid resin, which combines the advantages of organic and inorganic coatings. This allows the invention to withstand temperatures above 1000°C and also possess excellent flexibility and adhesion. The use of alumina-doped copper chromium black as a high-temperature resistant filler effectively improves temperature resistance and high-temperature quenching performance. The addition of additives enables the coating of this invention to form a uniform film, improving cross-cut adhesion and salt spray resistance.

[0007] Preferably, the additive is selected from one or more of the following: anti-settling agent bentonite, dispersant Solsperse 20000, and leveling agent BYK333.

[0008] The beneficial effects of this preferred method are that adding such additives can increase the salt spray resistance, high temperature resistance and impact resistance of the high temperature resistant and anti-corrosion coating.

[0009] Another aspect of the present invention provides a method for preparing the above-mentioned high-temperature resistant and anti-corrosion coating, the method comprising the following steps:

[0010] The organic-inorganic hybrid resin and the alumina-doped copper chromium black are added to the deionized water and mixed. Then, the acidic aluminum sol, the chromium trioxide and the additives are added in sequence and mixed and reacted to obtain the high-temperature resistant anti-corrosion coating.

[0011] Preferably, the preparation method is as follows: the organic-inorganic hybrid resin and the alumina-doped copper chromium black are added to the deionized water and stirred at 500-600 r / min for 10-15 min. Then, the acidic aluminum sol, the chromium trioxide and the additives are added in sequence and stirred at 2000-2200 r / min for 25-30 min. Subsequently, the mixture is ultrasonically dispersed for 10-15 min to obtain the high-temperature resistant anti-corrosion coating.

[0012] Preferably, the method for preparing the organic-inorganic hybrid resin is as follows:

[0013] The organic-inorganic hybrid resin is obtained by mixing and reacting isobutylphenyl dimethoxysilane and an organic weak acid in an alcohol solution.

[0014] Preferably, the method for preparing the organic-inorganic hybrid resin is as follows:

[0015] Isobutylphenyl dimethoxysilane and a weak organic acid are mixed in an alcohol solution and stirred at 500-600 r / min for 20-30 min to obtain the organic-inorganic hybrid resin.

[0016] Preferably, the organic weak acid is acetic acid and / or citric acid.

[0017] Preferably, the alcohol solution is an aqueous methanol solution and / or an aqueous ethanol solution.

[0018] Preferably, the molar ratio of the isobutylphenyl dimethoxysilane to the organic weak acid is (5~25):1.

[0019] Preferably, the method for preparing the isobutylphenyl dimethoxysilane is as follows:

[0020] Add magnesium and tetrahydrofuran in a mass ratio of 1:(2~2.5) to a container, reflux at 40~50℃ and add bromobenzene dropwise until the magnesium is completely dissolved to obtain Grignard reagent;

[0021] Under nitrogen protection, the Grignard reagent was cooled to room temperature, and isobutyltrimethoxysilane was added dropwise. The mixture was then refluxed at 50-65°C for 3-6 hours to obtain a mixed solution.

[0022] After cooling the mixed solution to room temperature, filter it, take the filtrate and distill it under reduced pressure, and collect the fraction at 130~145℃ / 3kPa, which is the isobutylphenyl dimethoxysilane.

[0023] Preferably, the method for preparing the isobutylphenyl dimethoxysilane is as follows:

[0024] Add magnesium and tetrahydrofuran in a mass ratio of 1:(2~2.5) to a container, and reflux bromobenzene at 40~50℃ and 100~150r / min until the magnesium is completely dissolved to obtain Grignard reagent;

[0025] Under nitrogen protection, the Grignard reagent was cooled to 25°C, and isobutyltrimethoxysilane was added dropwise. The mixture was then refluxed at 50-65°C for 3-6 hours to obtain a mixed solution.

[0026] The mixed solution was cooled to 25°C and filtered. The filtrate was then subjected to vacuum distillation, and the fraction collected at 130~145°C / 3kPa was identified as isobutylphenyl dimethoxysilane.

[0027] Preferably, the mass ratio of the bromobenzene to the isobutyltrimethoxysilane is 1:(3~5).

[0028] Preferably, the method for preparing the alumina doped with copper chromium black is as follows:

[0029] Aluminum hydroxide, copper nitrate, and chromium nitrate were added to pure water and mixed to form a homogeneous solution. Citric acid was then added, and the mixture was heated at 60-70°C until a gel was formed. The gel was then calcined at 700-950°C to obtain the alumina-doped copper chromium black.

[0030] Preferably, the ratio of the molar amount of citric acid to the sum of the molar amounts of copper nitrate and cadmium nitrate is 1:(1~2).

[0031] The present invention also provides the application of the above-mentioned high-temperature resistant anti-corrosion coating or the high-temperature resistant anti-corrosion coating prepared by the above-mentioned method in the preparation of high-temperature resistant anti-corrosion coatings.

[0032] Through the above technical solution, the present invention achieves the following beneficial effects:

[0033] 1. This invention uses an organic-inorganic hybrid resin as the main film-forming material, and adds alumina-doped copper chromium black and additives to give it excellent flexibility and adhesion, while being able to withstand high temperatures above 1000℃ and salt spray corrosion.

[0034] 2. This invention uses isobutylphenyl dimethoxysilane to prepare an organic-inorganic hybrid resin. The introduction of phenyl improves the toughness of the resin and enhances the anti-corrosion performance and cross-cut adhesion of the paint film.

[0035] 3. This invention uses alumina-doped copper chromium black to replace ordinary copper chromium black, which can effectively improve the temperature resistance and high-temperature quenching performance of the coating film, and can withstand 1000℃ calcination and 800℃ quenching 10 times without change. Attached Figure Description

[0036] Figure 1 This is a 5000x scanning electron microscope image of the alumina doped with copper chromium black prepared in Example 1;

[0037] Figure 2 This is a 10,000x scanning electron microscope image of the alumina doped with copper chromium black prepared in Example 1;

[0038] Figure 3 This is a cross-cut adhesion test chart of the high-temperature resistant anti-corrosion coating prepared in Example 1. Detailed Implementation

[0039] The specific embodiments of the present invention will be described in detail below with reference to examples. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0040] Example 1:

[0041] Preparation method of high temperature resistant and anti-corrosion coating:

[0042] (1) Preparation of isobutylphenyl dimethoxysilane:

[0043] Add 40g magnesium and 80g tetrahydrofuran to a three-necked flask, and reflux at 40℃ and 100r / min, then add 350g bromobenzene dropwise until the magnesium is completely dissolved to obtain Grignard reagent.

[0044] Under nitrogen protection, the Grignard reagent was cooled to 25°C, and 1050g of isobutyltrimethoxysilane was added dropwise. The mixture was then refluxed at 50°C for 6 hours to obtain a mixed solution.

[0045] The mixed solution was cooled to 25°C and filtered. The filtrate was then subjected to vacuum distillation, and the fraction collected at 130°C / 3 kPa was identified as isobutylphenyl dimethoxysilane.

[0046] (2) Preparation of organic-inorganic hybrid resin:

[0047] 5 mol of isobutylphenyl dimethoxysilane and 1 mol of acetic acid were mixed in 1000 g of 10% methanol aqueous solution and the mixture was stirred at 500 r / min for 20 min to hydrolyze the mixture and obtain an organic-inorganic hybrid resin.

[0048] (3) Preparation of copper chromium black doped with alumina:

[0049] 1 mol aluminum hydroxide, 1 mol copper nitrate and 2 mol chromium nitrate were added to deionized water and mixed to form a homogeneous solution. Then 3 mol citric acid was added and heated at 60°C until a gel was formed. The gel was then calcined at 700°C to obtain alumina-doped copper chromium black.

[0050] (4) Preparation of high-temperature resistant and anti-corrosion coatings:

[0051] Weigh out 30g of organic-inorganic hybrid resin, 30g of alumina-doped copper chromium black, 10g of deionized water, 5g of acidic aluminum sol, 5g of chromium trioxide, and 0.5g of bentonite. Add the organic-inorganic hybrid resin and alumina-doped copper chromium black to the deionized water and stir at 500r / min for 10min. Then add the acidic aluminum sol, chromium trioxide, and bentonite in sequence and stir at 2000r / min for 25min for hydrolysis reaction. Finally, ultrasonically disperse for 10min to obtain a high-temperature resistant anti-corrosion coating.

[0052] Example 2:

[0053] Preparation method of high temperature resistant and anti-corrosion coating:

[0054] (1) Preparation of isobutylphenyl dimethoxysilane:

[0055] Add 40g magnesium and 100g tetrahydrofuran to a three-necked flask, and reflux 300g bromobenzene at 50℃ and 150r / min until the magnesium is completely dissolved to obtain Grignard reagent;

[0056] Under nitrogen protection, the Grignard reagent was cooled to 25°C, and 1500g of isobutyltrimethoxysilane was added dropwise. The mixture was then refluxed at 65°C for 3 hours to obtain a mixed solution.

[0057] The mixed solution was cooled to 25°C and filtered. The filtrate was then subjected to vacuum distillation, and the fraction collected at 145°C / 3 kPa was identified as isobutylphenyl dimethoxysilane.

[0058] (2) Preparation of organic-inorganic hybrid resin:

[0059] 12.5 mol of isobutylphenyl dimethoxysilane and 0.5 mol of citric acid were mixed in 1000 g of 10% ethanol aqueous solution and stirred at 600 r / min for 30 min to hydrolyze the mixture, thus obtaining an organic-inorganic hybrid resin.

[0060] (3) Preparation of copper chromium black doped with alumina:

[0061] 1 mol aluminum hydroxide, 1 mol copper nitrate and 2 mol chromium nitrate were added to deionized water and mixed to form a homogeneous solution. Then 1.5 mol citric acid was added and heated at 70°C until a gel was formed. The gel was then calcined at 950°C to obtain alumina-doped copper chromium black.

[0062] (4) Preparation of high-temperature resistant and anti-corrosion coatings:

[0063] Weigh out 50g of organic-inorganic hybrid resin, 45g of alumina-doped copper chromium black, 30g of deionized water, 10g of acidic aluminum sol, 10g of chromium trioxide, 0.5g of Solsperse 20000, and 0.5g of BYK333. Add the organic-inorganic hybrid resin and alumina-doped copper chromium black to the deionized water and stir at 600r / min for 15min. Then add the acidic aluminum sol, chromium trioxide, Solsperse 20000, and BYK333 in sequence and stir at 2200r / min for 30min for hydrolysis reaction. Finally, ultrasonically disperse for 15min to obtain a high-temperature resistant anti-corrosion coating.

[0064] Example 3:

[0065] Preparation method of high temperature resistant and anti-corrosion coating:

[0066] (1) Preparation of isobutylphenyl dimethoxysilane:

[0067] Add 40g of magnesium and 92g of tetrahydrofuran to a three-necked flask, and reflux at 44℃ and 125r / min, then add 300g of bromobenzene dropwise until the magnesium is completely dissolved to obtain Grignard reagent;

[0068] Under nitrogen protection, the Grignard reagent was cooled to 25°C, and 1200g of isobutyltrimethoxysilane was added dropwise. The mixture was then refluxed at 58°C for 4.5h to obtain a mixed solution.

[0069] The mixed solution was cooled to 25°C and filtered. The filtrate was then subjected to vacuum distillation, and the fraction collected at 138°C / 3 kPa was identified as isobutylphenyl dimethoxysilane.

[0070] (2) Preparation of organic-inorganic hybrid resin:

[0071] 15 mol of isobutylphenyl dimethoxysilane, 0.5 mol of acetic acid, and 0.5 mol of citric acid were mixed in 500 g of 10% methanol aqueous solution and 500 g of 10% ethanol aqueous solution, and the mixture was stirred at 550 r / min for 25 min to hydrolyze the mixture, thus obtaining an organic-inorganic hybrid resin.

[0072] (3) Preparation of copper chromium black doped with alumina:

[0073] 1 mol aluminum hydroxide, 1 mol copper nitrate and 2 mol chromium nitrate were added to deionized water and mixed to form a homogeneous solution. Then 2 mol citric acid was added and heated at 65°C until a gel was formed. The gel was then calcined at 825°C to obtain alumina-doped copper chromium black.

[0074] Weigh the raw materials according to the following mass ratio:

[0075] The organic-inorganic hybrid resin consists of 40 parts, the alumina-doped copper chromium black consists of 38 parts, the deionized water consists of 20 parts, the acidic aluminum sol consists of 8 parts, the chromium trioxide consists of 8 parts, the bentonite consists of 0.2 parts, the Solsperse 20000 consists of 0.3 parts, and the BYK333 consists of 0.3 parts.

[0076] (4) Preparation of high-temperature resistant and anti-corrosion coatings:

[0077] Weigh out 40g of organic-inorganic hybrid resin, 38g of alumina-doped copper chromium black, 20g of deionized water, 8g of acidic aluminum sol, 8g of chromium trioxide, 0.2g of bentonite, 0.3g of Solsperse 20000, and 0.3g of BYK333. Add the organic-inorganic hybrid resin and alumina-doped copper chromium black to the deionized water and stir at 550 rpm for 12 min. Then add the acidic aluminum sol, chromium trioxide, bentonite, Solsperse 20000, and BYK333 in sequence and stir at 2100 rpm for 28 min for hydrolysis reaction. Finally, ultrasonically disperse for 12 min to obtain a high-temperature resistant anti-corrosion coating.

[0078] Comparative Example 1:

[0079] The other conditions are the same as in Example 3, except that isobutylphenyl dimethoxysilane in the raw materials for preparing the organic-inorganic hybrid resin is replaced with isobutyltrimethoxysilane.

[0080] Comparative Example 2:

[0081] The other conditions are the same as in Example 3, except that the alumina-doped copper chromium black in the raw materials for preparing the high-temperature resistant anti-corrosion coating is replaced with copper chromium black.

[0082] Comparative Example 3:

[0083] The other conditions are the same as in Example 3, except that the raw materials used to prepare the high-temperature resistant anti-corrosion coating do not include bentonite, Solsperse 20000, and BYK333.

[0084] The high-temperature resistant and anti-corrosion coatings obtained in the above examples and comparative examples were sprayed onto 316L stainless steel plates (substrate sandblasted to Sa2.5 grade) using compressed air method, cured at 25°C for 2 hours, and the film thickness was controlled at 30±5μm to obtain a high-temperature resistant and anti-corrosion coating.

[0085] The high-temperature resistant anti-corrosion coatings obtained by spraying the high-temperature resistant anti-corrosion coatings in the examples and comparative examples were subjected to performance tests, and the test standards are as follows:

[0086] Appearance: Visually inspect the smoothness of the paint film;

[0087] Adhesion: Tested according to GB / T 5210;

[0088] Temperature resistance: After continuous heating in a muffle furnace for 24 hours, check whether the paint film peels off or blisters;

[0089] Salt spray resistance: Tested according to GB / T 1771, the salt spray resistance time is 2000h;

[0090] Impact resistance: Tested according to GB / T 1732;

[0091] High-temperature quenching resistance: After heating at 800℃ for 2 hours, the material was directly quenched, and the paint film peeling was tested.

[0092] The test results are shown in Table 1:

[0093] Table 1: Performance test results of the high-temperature resistant and anti-corrosion coatings obtained in the examples and comparative examples

[0094]

[0095] Table 1 shows that, compared to Example 3, Comparative Example 1, due to the use of isobutyltrimethoxysilane instead of isobutylphenyldimethoxysilane with introduced phenyl groups, exhibited significantly lower adhesion and impact resistance, and also showed poorer salt spray resistance for 2000 hours. The paint film peeled off after five quenching cycles, indicating that introducing a benzene ring into isobutyltrimethoxysilane can improve the performance of this high-temperature resistant anti-corrosion coating. Comparing Example 3 and Comparative Example 2, it can be seen that adding alumina to copper chromate black significantly enhances the temperature resistance and high-temperature quenching resistance of this high-temperature resistant anti-corrosion coating, having a significant impact on its high-temperature tolerance. (Observation) Figure 1 and Figure 2It was found that the prepared alumina-doped copper chromium black was spherical with a diameter between 0.5 and 1 μm, indicating that the alumina-doped copper chromium black prepared by the high-temperature calcination gel method had uniform particle size and no obvious agglomeration. Compared with Example 1, Comparative Example 3 did not contain the additives bentonite, Solsperse 20000 and BYK333, resulting in lower adhesion, salt spray resistance, impact resistance and high-temperature quenching resistance than the high-temperature anti-corrosion coating obtained in Example 3. Figure 3 The cross-cut adhesion test chart clearly shows that the coating produced by this paint has good adhesion and no peeling.

[0096] As can be seen from the above description, the present invention has the following advantages: excellent adhesion, high temperature resistance, salt spray corrosion resistance and impact resistance.

[0097] The preferred embodiments of the present invention have been described in detail above with reference to the examples. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0098] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0099] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing a high-temperature resistant anti-corrosion coating, characterized in that, By weight, 30-50 parts of organic-inorganic hybrid resin and 30-45 parts of alumina-doped copper chromium black are added to 10-30 parts of deionized water and mixed. Then, 5-10 parts of acidic aluminum sol, 5-10 parts of chromium trioxide, and 0.5-1 parts of additives are added sequentially and mixed to react, thereby obtaining the high-temperature resistant anti-corrosion coating. The organic-inorganic hybrid resin is prepared by mixing isobutylphenyl dimethoxysilane and an organic weak acid in an alcohol solution to obtain the organic-inorganic hybrid resin. The alumina-doped copper chromium black is prepared by adding aluminum hydroxide, copper nitrate, and chromium nitrate to pure water, mixing to form a uniform solution, adding citric acid, heating at 60-70°C to form a gel, and then calcining the gel at 700-950°C to obtain the alumina-doped copper chromium black. The molar ratio of citric acid to the sum of the molar amounts of copper nitrate and cadmium nitrate is 1:(1-2).

2. The preparation method according to claim 1, characterized in that, The additives are selected from one or more of the following: anti-settling agent bentonite, dispersant Solsperse 20000, and leveling agent BYK333.

3. The preparation method according to claim 1, characterized in that, The organic weak acid is acetic acid and / or citric acid; The alcohol solution is an aqueous solution of methanol and / or an aqueous solution of ethanol.

4. The preparation method according to claim 1, characterized in that, The molar ratio of isobutylphenyl dimethoxysilane to the organic weak acid is (5~25):

1.

5. The preparation method according to claim 1, characterized in that, The method for preparing the isobutylphenyl dimethoxysilane is as follows: Add magnesium and tetrahydrofuran in a mass ratio of 1:(2~2.5) to a container, reflux at 40~50℃ and add bromobenzene dropwise until the magnesium is completely dissolved to obtain Grignard reagent; Under nitrogen protection, the Grignard reagent was cooled to room temperature, and isobutyltrimethoxysilane was added dropwise. The mixture was then refluxed at 50-65°C for 3-6 hours to obtain a mixed solution. After cooling the mixed solution to room temperature, filter it, take the filtrate and distill it under reduced pressure, and collect the fraction at 130~145℃ / 3kPa, which is the isobutylphenyl dimethoxysilane.

6. The preparation method according to claim 5, characterized in that, The mass ratio of the bromobenzene to the isobutyltrimethoxysilane is 1:(3~5).

7. The application of a high-temperature resistant anti-corrosion coating prepared by any one of claims 1 to 6 in the preparation of high-temperature resistant anti-corrosion coatings.

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