Corrosion-resistant coating and preparation method thereof

Abstract

The invention provides a corrosion-resistant coating and a preparation method thereof, and belongs to the technical field of coatings. The corrosion-resistant coating comprises a component A and a component B, the component A is prepared from the following raw materials in parts by mass: 40 to 50 parts of waterborne epoxy resin, 5 to 8 parts of sulfonated molybdenum disulfide, 0.5 to 2 parts of sodium polystyrenesulfonate, 1 to 2 parts of silane coupling agent, 2 to 3 parts of polyacrylic acid, 0.1 to 0.5 part of defoaming agent and 20 to 30 parts of water; and the component B is prepared from a water-based amine curing agent. According to the corrosion-resistant coating, through the synergistic effect of the components, coupling of chemical modification and physical barrier is achieved, and the corrosion resistance and the mechanical property of the coating are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and particularly relates to a corrosion-resistant coating and a preparation method thereof. Background Art

[0002] With the advancement of environmental protection policies and technological progress, waterborne coatings have gradually become an important choice in the field of corrosion resistance due to their environmental protection characteristics such as low VOC (volatile organic compound) emissions, non-toxicity, and non-flammability. However, due to the evaporation of waterborne solvents, waterborne coatings often have tiny pores, reducing the barrier effect against corrosive media. Therefore, it is necessary to improve the corrosion resistance of waterborne coatings. Summary of the Invention

[0003] In order to solve the problems mentioned in the background art, the present invention provides a corrosion-resistant coating, which through the synergistic effect between components, achieves the coupling of chemical modification and physical barrier, significantly improving the corrosion resistance and mechanical properties of the coating.

[0004] Specifically: A corrosion-resistant coating, comprising component A and component B; By mass, the raw material composition of component A includes: 40 - 50 parts of waterborne epoxy resin, 5 - 8 parts of sulfonated molybdenum disulfide, 0.5 - 2 parts of sodium polystyrene sulfonate, 1 - 2 parts of silane coupling agent, 2 - 3 parts of polyacrylic acid, 0.1 - 0.5 parts of defoamer, and 20 - 30 parts of water; The raw material composition of component B is a waterborne amine curing agent.

[0005] Further, the solid content of the waterborne epoxy resin is 50% - 60%.

[0006] Further, the sulfonated molybdenum disulfide is selected from molybdenum disulfide with a particle size less than 1 μm for modification.

[0007] Further, the molecular weight of the sodium polystyrene sulfonate is 50000 - 70000 Da.

[0008] Further, the molecular weight of the polyacrylic acid is 2000 - 5000 Da.

[0009] Further, the water is deionized water.

[0010] In addition, the present invention also provides a preparation method of the above-mentioned corrosion-resistant coating, wherein, The preparation steps of component A include: Step 1: According to the ratio, mix sulfonated molybdenum disulfide, sodium polystyrene sulfonate and part of the water, ultrasonically disperse evenly, add the hydrolyzed silane coupling agent, heat and stir to react to obtain a sulfonated molybdenum disulfide @ sodium polystyrene sulfonate @ silane coupling agent composite; Step 2: Mix waterborne epoxy resin, polyacrylic acid, and the remaining water according to the ratio, add the sulfonated molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent complex obtained in Step 1 and an antifoaming agent, and stir and mix to obtain Component A; The preparation steps of Component B include: separately packaging the waterborne amine curing agent to obtain Component B.

[0011] Further, the treatment process of the sulfonated molybdenum disulfide includes: mixing molybdenum disulfide powder and concentrated sulfuric acid at a mass ratio of 1:1 - 1.5, stirring and reacting at 60 - 65 °C for 2 - 2.5 h, centrifuging and washing until neutral, and drying to obtain sulfonated molybdenum disulfide.

[0012] Further, the hydrolysis process of the silane coupling agent includes: mixing the silane coupling agent and water at a mass ratio of 1:3 - 5, adjusting the pH to 4 - 5 with acetic acid, and hydrolyzing for 30 - 35 min to obtain the hydrolyzed silane coupling agent.

[0013] Further, the temperature of heating and stirring in Step 1 is controlled at 50 - 55 °C.

[0014] Compared with the prior art, the beneficial features of the present invention are as follows: 1. The corrosion-resistant coating provided by the present invention contains a sulfonated molybdenum disulfide@ sodium polystyrene sulfonate@silane coupling agent complex in its components. Utilizing the layered structure of molybdenum disulfide itself, it can form a physical barrier to extend the diffusion path of the corrosive medium and prevent the corrosive medium (such as water, oxygen, ions, etc.) from contacting the substrate; the introduction of polystyrene sulfonic acid can further enhance the dispersibility of the sulfonated molybdenum disulfide@ sodium polystyrene sulfonate@silane coupling agent complex in the waterborne epoxy resin emulsion, making the barrier effect more uniform. At the same time, the sulfonic acid groups on sodium polystyrene sulfonate can react with the silane coupling agent, and the silane coupling agent can also form chemical bonds with the surface of the epoxy resin and the filler, strengthening the interfacial bonding force. It is precisely by utilizing the synergistic effect between the components that the sulfonated molybdenum disulfide@ sodium polystyrene sulfonate@silane coupling agent complex can be stably distributed in the epoxy resin matrix and form a dense physical barrier, effectively delaying the penetration of the corrosive medium.

[0015] 2. The corrosion-resistant coating provided by the present invention contains polyacrylic acid in its components. Polyacrylic acid acts as a crosslinking agent to crosslink with the epoxy groups in the waterborne epoxy resin emulsion to form a three-dimensional network structure. This crosslinked structure can improve the mechanical properties of the coating. At the same time, polyacrylic acid also helps to maintain the dispersion stability of the system and prevent substances such as the sulfonated molybdenum disulfide@ sodium polystyrene sulfonate@silane coupling agent complex from settling and aggregating into clusters.

[0016] 3. The corrosion-resistant coating provided by the present invention can also endow the coating with hydrophobicity to a certain extent due to polyacrylic acid. At the same time, the surface properties of the modified sulfonated molybdenum disulfide@polystyrene sulfonate@silane coupling agent composite may also affect the wettability of the coating. By using the combined action of the two, the water contact angle on the coating surface is increased, and the spreading property of water on the coating surface is reduced, thereby improving the hydrophobic performance. Detailed implementation manners

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0018] For the convenience of those skilled in the art to implement the present invention, some reagents used in the examples and comparative examples are described below: Waterborne epoxy resin: waterborne epoxy emulsion, solid content 60%, Zhonghe Chemistry (Shandong); Molybdenum disulfide: particle size 500nm, Hebei Tenshuang Metal Materials; Sodium polystyrene sulfonate: Guangzhou Yuanda New Materials, average molecular weight (Mw) normal distribution 60000; Silane coupling agent: KH-560, Qufu Yishun Chemical Industry; Polyacrylic acid: Tai'an Yingshun Chemical Industry, average molecular weight (Mw) normal distribution 3000; Defoamer: BYK-024, Shanghai Hongjun New Materials Technology; Waterborne amine curing agent: Wuhan Huaxiang Kejie Biotechnology.

[0019] To verify the beneficial effects of the present invention, the following examples and comparative examples are specifically designed and corresponding experiments are carried out for verification.

[0020] Example 1 A corrosion-resistant coating, including component A and component B; By mass, the raw material composition of component A includes: 40 parts of waterborne epoxy resin, 8 parts of sulfonated molybdenum disulfide, 2 parts of sodium polystyrene sulfonate, 2 parts of silane coupling agent, 3 parts of polyacrylic acid, 0.5 part of defoamer, and 20 parts of deionized water; The raw material composition of component B is a waterborne amine curing agent.

[0021] Among them, The preparation steps of component A include: S1. Mix molybdenum disulfide powder and concentrated sulfuric acid at a mass ratio of 1:1, stir and react at 60 °C for 2 h, centrifuge and wash until neutral, and dry to obtain sulfonated molybdenum disulfide.

[0022] S2. Mix silane coupling agent and deionized water at a mass ratio of 1:3, adjust the pH to 4 with acetic acid, hydrolyze for 30 min, and collect the hydrolyzed silane coupling agent.

[0023] S3. According to the ratio, mix the sulfonated molybdenum disulfide obtained in S1, sodium polystyrene sulfonate and 10 parts of deionized water, ultrasonically disperse evenly at 800 rpm, add the hydrolyzed silane coupling agent obtained in S2, heat to 50 °C, and stir and react at 300 rpm to obtain a sulfonated molybdenum disulfide@polystyrene sulfonate@silane coupling agent composite; S4. According to the ratio, stir and mix waterborne epoxy resin, polyacrylic acid and the remaining 10 parts of deionized water, add the sulfonated molybdenum disulfide@polystyrene sulfonate@silane coupling agent composite and defoamer obtained in S3, and stir and mix to obtain Component A.

[0024] The preparation steps of Component B include: separately packaging the waterborne amine curing agent to obtain Component B.

[0025] Example 2 A corrosion-resistant coating, comprising Component A and Component B; By mass, the raw material composition of Component A includes: 50 parts of waterborne epoxy resin, 5 parts of sulfonated molybdenum disulfide, 0.5 part of sodium polystyrene sulfonate, 1 part of silane coupling agent, 3 parts of polyacrylic acid, 0.5 part of defoamer, and 30 parts of deionized water; The raw material composition of Component B is a waterborne amine curing agent.

[0026] Among them, The preparation steps of Component A include: S1. Mix molybdenum disulfide powder and concentrated sulfuric acid at a mass ratio of 1:1.5, stir and react at 65 °C for 2.5 h, centrifuge and wash until neutral, and dry to obtain sulfonated molybdenum disulfide.

[0027] S2. Mix silane coupling agent and deionized water at a mass ratio of 1:5, adjust the pH to 5 with acetic acid, hydrolyze for 35 min, and collect the hydrolyzed silane coupling agent.

[0028] S3. According to the ratio, mix the sulfonated molybdenum disulfide obtained in S1, sodium polystyrene sulfonate and 10 parts of deionized water, ultrasonically disperse evenly at 800 rpm, add the hydrolyzed silane coupling agent obtained in S2, heat to 55 °C, and stir and react at 300 rpm to obtain a sulfonated molybdenum disulfide@polystyrene sulfonate@silane coupling agent composite; S4. According to the ratio, stir and mix the waterborne epoxy resin, polyacrylic acid, and the remaining 20 parts of deionized water, add the sulfonated molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent complex obtained in S3 and the defoaming agent, and stir and mix to obtain Component A.

[0029] The preparation steps of Component B include: separately packaging the waterborne amine curing agent to obtain Component B.

[0030] Example 3 A corrosion-resistant coating includes Component A and Component B; By mass, the raw material composition of Component A includes: 50 parts of waterborne epoxy resin, 8 parts of sulfonated molybdenum disulfide, 2 parts of sodium polystyrene sulfonate, 2 parts of silane coupling agent, 2 parts of polyacrylic acid, 0.1 part of defoaming agent, and 30 parts of deionized water; The raw material composition of Component B is a waterborne amine curing agent.

[0031] Among them, The preparation steps of Component A include: S1. Mix molybdenum disulfide powder and concentrated sulfuric acid at a mass ratio of 1:1.5, stir and react at 60 °C for 2.5 h, centrifuge and wash until neutral, and dry to obtain sulfonated molybdenum disulfide.

[0032] S2. Mix the silane coupling agent and deionized water at a mass ratio of 1:5, adjust the pH to 4 with acetic acid, hydrolyze for 35 min, and collect the hydrolyzed silane coupling agent.

[0033] S3. According to the ratio, mix the sulfonated molybdenum disulfide obtained in S1, sodium polystyrene sulfonate, and 10 parts of deionized water, ultrasonically disperse evenly at 800 rpm, add the hydrolyzed silane coupling agent obtained in S2, heat to 50 °C, and stir and react at 300 rpm to obtain the sulfonated molybdenum disulfide@ sodium polystyrene sulfonate@silane coupling agent complex; S4. According to the ratio, stir and mix the waterborne epoxy resin, polyacrylic acid, and the remaining 20 parts of deionized water, add the sulfonated molybdenum disulfide@ sodium polystyrene sulfonate@silane coupling agent complex obtained in S3 and the defoaming agent, and stir and mix to obtain Component A.

[0034] The preparation steps of Component B include: separately packaging the waterborne amine curing agent to obtain Component B.

[0035] Comparative Example 1 A coating includes Component A and Component B; By mass, the raw material composition of Component A includes: 40 parts of waterborne epoxy resin, 2 parts of sodium polystyrene sulfonate, 2 parts of silane coupling agent, 3 parts of polyacrylic acid, 0.5 part of defoaming agent, and 20 parts of deionized water; The raw material composition of Component B is a waterborne amine curing agent.

[0036] Among them, The preparation steps of component A include: according to the ratio, mixing waterborne epoxy resin with sodium polystyrene sulfonate, silane coupling agent, polyacrylic acid, defoaming agent and deionized water by stirring to obtain component A by stirring and mixing.

[0037] The preparation steps of component B include: packaging the waterborne amine curing agent separately to obtain component B.

[0038] Comparative Example 2 A coating includes component A and component B; Calculated by mass parts, among them, the raw material composition of component A includes: 40 parts of waterborne epoxy resin, 8 parts of sulfonated molybdenum disulfide, 2 parts of silane coupling agent, 3 parts of polyacrylic acid, 0.5 part of defoaming agent, and 20 parts of deionized water; The raw material composition of component B is a waterborne amine curing agent.

[0039] Among them, The preparation steps of component A include: S1. Mix molybdenum disulfide powder with concentrated sulfuric acid at a mass ratio of 1:1, stir and react at 60 °C for 2 h, centrifuge and wash until neutral, and dry to obtain sulfonated molybdenum disulfide.

[0040] S2. Mix the silane coupling agent with deionized water at a mass ratio of 1:3, adjust the pH to 4 with acetic acid, hydrolyze for 30 min, and collect the hydrolyzed silane coupling agent.

[0041] S3. According to the ratio, mix the sulfonated molybdenum disulfide obtained in S1 with 10 parts of deionized water, disperse evenly by ultrasonic at 800 rpm, add the hydrolyzed silane coupling agent obtained in S2, heat to 50 °C, stir and react at 300 rpm, and collect the solid product A; S4. According to the ratio, mix the waterborne epoxy resin with polyacrylic acid and the remaining 10 parts of deionized water by stirring, add the solid product A and the defoaming agent obtained in S3, and stir and mix to obtain component A.

[0042] The preparation steps of component B include: packaging the waterborne amine curing agent separately to obtain component B.

[0043] Comparative Example 3 A coating includes component A and component B; Calculated by mass parts, among them, the raw material composition of component A includes: 40 parts of waterborne epoxy resin, 8 parts of sulfonated molybdenum disulfide, 2 parts of sodium polystyrene sulfonate, 3 parts of polyacrylic acid, 0.5 part of defoaming agent, and 20 parts of deionized water; The raw material composition of component B is a waterborne amine curing agent.

[0044] Among them, The preparation steps of component A include: S1. Mix molybdenum disulfide powder and concentrated sulfuric acid at a mass ratio of 1:1, stir and react at 60 °C for 2 h, centrifuge and wash until neutral, and dry to obtain sulfonated molybdenum disulfide.

[0045] S2. According to the ratio, mix the sulfonated molybdenum disulfide obtained in S1, sodium polystyrene sulfonate and 10 parts of deionized water, and ultrasonically disperse evenly at 800 rpm, and collect the solid product B; S3. According to the ratio, stir and mix waterborne epoxy resin, polyacrylic acid and the remaining 10 parts of deionized water, add the solid product B obtained in S2 and an antifoaming agent, and stir and mix to obtain component A.

[0046] The preparation steps of component B include: separately packaging the waterborne amine curing agent to obtain component B.

[0047] Perform corrosion resistance tests and mechanical property tests on the coatings obtained in the above Examples 1-3 and Comparative Examples 1-3. Sample preparation: Stir the coating at a mass ratio of component A: component B of 100:20 for 5 min until uniform, spray it onto the surface of the cast iron substrate to obtain the corresponding sample, cure the sample at 60 °C for 4 h, and control the coating thickness at about 120 μm.

[0048] 1. Acid resistance test: Refer to GB / T9274, put the sample into 10% H2SO4 chemical reagent, and record the appearance of the soaked sample once a day to check whether the coating is complete, whether there are bubbles and peeling, and keep it for 1500 h. The process cut-off time is based on the occurrence of adverse states such as bubbles, peeling, and cracking.

[0049] 2. Alkali resistance test: Refer to GB / T9274, put the sample into 10% NaOH chemical reagent, and record the appearance of the soaked sample once a day to check whether the coating is complete, whether there are bubbles and peeling, and keep it for 1500 h. The process cut-off time is based on the occurrence of adverse states such as bubbles, peeling, and cracking.

[0050] 3. Salt spray resistance test: Refer to GB / T1771, use a blade to draw a cross on the sample, place it in a salt spray test chamber, turn on the salt spray test chamber, and observe whether there are bubbles, peeling, and cracking of the paint film around the cross after 1500 h as the basis.

[0051] 4. Abrasion resistance: Refer to GB / T 1768, test according to the conditions of 1000 g / 1000 revolutions to obtain the mass loss value.

[0052] The test results are shown in the following table: From the above test results, it can be seen that the corrosion resistance and wear resistance of Examples 1-3 are excellent.

[0053] In the formulation systems of Comparative Examples 1-3, it is impossible to form the sulfonated molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent complex, resulting in the corrosion resistance and wear resistance of their coatings being worse than those of Examples 1-3.

[0054] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A corrosion-resistant coating, characterized in that: It includes component A and component B; In terms of mass fraction, the raw material composition of component A includes: 40-50 parts of waterborne epoxy resin, 5-8 parts of sulfonated molybdenum disulfide, 0.5-2 parts of sodium polystyrene sulfonate, 1-2 parts of silane coupling agent, 2-3 parts of polyacrylic acid, 0.1-0.5 parts of defoaming agent, and 20-30 parts of water; The raw material composition of component B is a water-based amine curing agent.

2. The corrosion-resistant coating according to claim 1, characterized in that: The solid content of the waterborne epoxy resin is 50%-60%.

3. The corrosion-resistant coating according to claim 1, characterized in that: The sulfonated molybdenum disulfide is modified with molybdenum disulfide having a particle size less than 1 μm.

4. The corrosion-resistant coating according to claim 1, characterized in that: The molecular weight of the sodium polystyrene sulfonate is 50000-70000Da.

5. The corrosion-resistant coating according to claim 1, characterized in that: The weight of the polyacrylic acid is 2000-5000Da.

6. The corrosion-resistant coating according to claim 1, characterized in that: The water is deionized water.

7. A method for preparing a corrosion-resistant coating according to any one of claims 1 to 6, characterized in that: in, The preparation steps of component A include: Step 1: according to the ratio, sulfonated molybdenum disulfide, sodium polystyrene sulfonate and part of water are mixed, ultrasonically dispersed evenly, the hydrolyzed silane coupling agent is added, heated and stirred for reaction, and a sulfonated molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent complex is obtained; Step 2: Mix the waterborne epoxy resin, polyacrylic acid and the remaining water according to the proportion, add the sulfonated molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent complex and the defoamer obtained in step 1, and mix them by stirring to obtain component A; The step of preparing component B comprises: separately packaging the water-based amine curing agent to obtain component B.

8. The method for preparing the corrosion-resistant coating according to claim 7, characterized in that: The treatment process of the sulfonated molybdenum disulfide comprises: mixing molybdenum disulfide powder and concentrated sulfuric acid at a mass ratio of 1:1-1.5, stirring and reacting at 60-65° C. for 2-2.5 hours, centrifuging and washing until neutral, and drying to obtain the sulfonated molybdenum disulfide.

9. The method for preparing the corrosion-resistant coating according to claim 7, characterized in that: The hydrolysis process of the silane coupling agent comprises: mixing the silane coupling agent and water at a mass ratio of 1:3-5, adjusting the pH to 4-5 with acetic acid, and hydrolyzing for 30-35 minutes to obtain the hydrolyzed silane coupling agent.

10. The method for preparing the corrosion-resistant coating according to claim 7, characterized in that: The temperature of heating and stirring in step 1 is controlled at 50-55°C.

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