Corrosion-resistant coating and preparation method thereof

Abstract

The present invention provides a corrosion-resistant coating and a preparation method thereof, belonging to the field of coating technology. The corrosion-resistant coating comprises component A and component B; in parts by mass, component A comprises: 40-50 parts of a water-based epoxy resin, 5-8 parts of concentrated sulfuric acid-modified molybdenum disulfide, 0.5-2 parts of sodium polystyrene sulfonate, 1-2 parts of a silane coupling agent, 2-3 parts of polyacrylic acid, 0.1-0.5 parts of a defoaming agent, and 20-30 parts of water; and component B comprises a water-based amine curing agent. The corrosion-resistant coating, through the synergistic effect between the components, couples chemical modification with physical barrier properties, significantly improving the corrosion resistance and mechanical properties of the coating.

Description

Technical Field

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

[0002] With the advancement of environmental protection policies and technological progress, water-based coatings are becoming an increasingly important choice in the corrosion resistance field due to their environmentally friendly properties, such as low VOC (volatile organic compound) emissions, non-toxicity, and non-flammability. However, the evaporation of aqueous solvents often leads to the formation of micropores in water-based coatings, reducing their barrier effect against corrosive media. Therefore, it is necessary to improve the corrosion resistance of water-based coatings. Summary of the Invention

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

[0004] Specifically:

[0005] A corrosion-resistant coating comprising a component A and a component B;

[0006] In parts by mass, the raw materials of component A include: 40-50 parts of waterborne epoxy resin, 5-8 parts of concentrated sulfuric acid-modified 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;

[0007] The raw material composition of component B is a water-based amine curing agent;

[0008] The concentrated sulfuric acid modified molybdenum disulfide treatment process includes: mixing molybdenum disulfide powder and concentrated sulfuric acid in 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 concentrated sulfuric acid modified molybdenum disulfide.

[0009] Furthermore, the solid content of the waterborne epoxy resin is 50%-60%.

[0010] Furthermore, the concentrated sulfuric acid-modified molybdenum disulfide is modified with molybdenum disulfide having a particle size of less than 1 μm.

[0011] Furthermore, the molecular weight of the sodium polystyrene sulfonate is 50,000-70,000 Da.

[0012] Furthermore, the weight of the polyacrylic acid is 2000-5000Da.

[0013] Furthermore, the water is deionized water.

[0014] In addition, the present invention also provides a method for preparing the above-mentioned corrosion-resistant coating, wherein:

[0015] The preparation steps of component A include:

[0016] Step 1: Concentrated sulfuric acid-modified molybdenum disulfide, sodium polystyrene sulfonate, and a portion of water are mixed according to a ratio, ultrasonically dispersed, and the hydrolyzed silane coupling agent is added, heated and stirred for reaction to obtain a concentrated sulfuric acid-modified molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent complex;

[0017] Step 2: Mix the water-based epoxy resin, polyacrylic acid, and the remaining water according to the ratio, add the concentrated sulfuric acid-modified molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent complex and the defoamer obtained in Step 1, and stir to obtain component A;

[0018] The step of preparing component B comprises: separately packaging the water-based amine curing agent to obtain component B.

[0019] Furthermore, the hydrolysis process of the silane coupling agent includes: mixing the silane coupling agent and water in 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.

[0020] Furthermore, the temperature of heating and stirring in step 1 is controlled at 50-55°C.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. The corrosion-resistant coating provided herein comprises a concentrated sulfuric acid-modified molybdenum disulfide, sodium polystyrene sulfonate, and silane coupling agent complex. Molybdenum disulfide, with its layered structure, forms a physical barrier, extending the diffusion path of corrosive media and preventing them (such as water, oxygen, and ions) from contacting the substrate. The addition of polystyrene sulfonic acid further enhances the dispersibility of the concentrated sulfuric acid-modified molybdenum disulfide, sodium polystyrene sulfonate, and silane coupling agent complex in the aqueous epoxy resin emulsion, resulting in a more uniform barrier effect. Furthermore, the sulfonic acid groups on the sodium polystyrene sulfonate react with the silane coupling agent, which in turn chemically bonds with the epoxy resin and filler surfaces, strengthening interfacial bonding. This synergistic effect allows the concentrated sulfuric acid-modified molybdenum disulfide, sodium polystyrene sulfonate, and silane coupling agent complex to be stably distributed within the epoxy resin matrix, forming a dense physical barrier and effectively slowing the penetration of corrosive media.

[0023] 2. The corrosion-resistant coating provided by the present invention includes polyacrylic acid, which acts as a crosslinking agent and reacts with epoxy groups in the waterborne epoxy resin emulsion to form a three-dimensional network structure. This crosslinked structure improves the mechanical properties of the coating. Furthermore, polyacrylic acid helps maintain the dispersion stability of the system, preventing sedimentation and aggregation of substances such as the concentrated sulfuric acid-modified molybdenum disulfide, sodium polystyrene sulfonate, and silane coupling agent complex.

[0024] 3. The surface properties of the modified concentrated sulfuric acid-modified molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent composite of the corrosion-resistant coating provided by the present invention may also affect the wettability of the coating, thereby increasing the water contact angle on the coating surface and reducing the spreading of water on the coating surface, thereby improving the hydrophobicity. DETAILED DESCRIPTION

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, 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 only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0026] In order to facilitate those skilled in the art to implement the present invention, some of the reagents used in the examples and comparative examples are now described:

[0027] Waterborne epoxy resin: waterborne epoxy emulsion, solid content 60%, Zhonghe Chemical (Shandong);

[0028] Molybdenum disulfide: particle size 500nm, Hebei Teng bimetallic material;

[0029] Sodium polystyrene sulfonate: Guangzhou Yuanda New Materials, average molecular weight (Mw) normal distribution 60000;

[0030] Silane coupling agent: KH-560, Qufu Yishun Chemical;

[0031] Polyacrylic acid: Tai'an Yingshun Chemical, average molecular weight (Mw) normal distribution 3000;

[0032] Defoaming agent: BYK-024, Shanghai Hongjun New Material Technology;

[0033] Water-based amine curing agent: Wuhan Huaxiang Kejie Biotechnology.

[0034] In order to verify the beneficial effects of the present invention, the following examples and comparative examples are designed and corresponding experiments are carried out to verify them.

[0035] Example 1

[0036] A corrosion-resistant coating comprising a component A and a component B;

[0037] In parts by mass, the raw materials of component A include: 40 parts of waterborne epoxy resin, 8 parts of concentrated sulfuric acid-modified molybdenum disulfide, 2 parts of sodium polystyrene sulfonate, 2 parts of silane coupling agent, 3 parts of polyacrylic acid, 0.5 parts of defoaming agent, and 20 parts of deionized water;

[0038] The raw material composition of component B is a water-based amine curing agent.

[0039] in,

[0040] The preparation steps of component A include:

[0041] S1. Molybdenum disulfide powder and concentrated sulfuric acid were mixed in a mass ratio of 1:1, stirred and reacted at 60°C for 2h, centrifuged and washed until neutral, and dried to obtain concentrated sulfuric acid-modified molybdenum disulfide.

[0042] S2. Mix the silane coupling agent and deionized water in a mass ratio of 1:3, adjust the pH to 4 with acetic acid, hydrolyze for 30 minutes, and collect the hydrolyzed silane coupling agent.

[0043] S3, according to the ratio, the concentrated sulfuric acid modified molybdenum disulfide obtained in S1, sodium polystyrene sulfonate and 10 parts of deionized water were mixed, and ultrasonically dispersed at 800 rpm, and the hydrolyzed silane coupling agent obtained in S2 was added, and the mixture was heated to 50°C and stirred at 300 rpm to obtain a concentrated sulfuric acid modified molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent complex;

[0044] S4. According to the proportion, stir and mix the water-based epoxy resin, polyacrylic acid, and the remaining 10 parts of deionized water, add the concentrated sulfuric acid-modified molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent complex and the defoamer obtained in S3, and stir and mix to obtain component A.

[0045] The step of preparing component B comprises: separately packaging the water-based amine curing agent to obtain component B.

[0046] Example 2

[0047] A corrosion-resistant coating comprising a component A and a component B;

[0048] In parts by mass, the raw materials of component A include: 50 parts of waterborne epoxy resin, 5 parts of concentrated sulfuric acid-modified molybdenum disulfide, 0.5 parts of sodium polystyrene sulfonate, 1 part of silane coupling agent, 3 parts of polyacrylic acid, 0.5 parts of defoaming agent, and 30 parts of deionized water;

[0049] The raw material composition of component B is a water-based amine curing agent.

[0050] in,

[0051] The preparation steps of component A include:

[0052] S1. Molybdenum disulfide powder and concentrated sulfuric acid were mixed in a mass ratio of 1:1.5, stirred and reacted at 65°C for 2.5 hours, centrifuged and washed until neutral, and dried to obtain concentrated sulfuric acid-modified molybdenum disulfide.

[0053] S2. Mix the silane coupling agent and deionized water in a mass ratio of 1:5, adjust the pH to 5 with acetic acid, hydrolyze for 35 minutes, and collect the hydrolyzed silane coupling agent.

[0054] S3. According to the ratio, the concentrated sulfuric acid-modified molybdenum disulfide obtained in S1, sodium polystyrene sulfonate and 10 parts of deionized water were mixed, and ultrasonically dispersed at 800 rpm. The hydrolyzed silane coupling agent obtained in S2 was added, and the mixture was heated to 55° C. and stirred at 300 rpm to react to obtain a concentrated sulfuric acid-modified molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent complex.

[0055] S4. According to the proportion, stir and mix the water-based epoxy resin, polyacrylic acid, and the remaining 20 parts of deionized water, add the concentrated sulfuric acid-modified molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent complex and the defoamer obtained in S3, and stir and mix to obtain component A.

[0056] The step of preparing component B comprises: separately packaging the water-based amine curing agent to obtain component B.

[0057] Example 3

[0058] A corrosion-resistant coating comprising a component A and a component B;

[0059] In parts by mass, the raw materials of component A include: 50 parts of waterborne epoxy resin, 8 parts of concentrated sulfuric acid-modified molybdenum disulfide, 2 parts of sodium polystyrene sulfonate, 2 parts of silane coupling agent, 2 parts of polyacrylic acid, 0.1 parts of defoaming agent, and 30 parts of deionized water;

[0060] The raw material composition of component B is a water-based amine curing agent.

[0061] in,

[0062] The preparation steps of component A include:

[0063] S1. Molybdenum disulfide powder and concentrated sulfuric acid were mixed in a mass ratio of 1:1.5, stirred and reacted at 60°C for 2.5h, centrifuged and washed until neutral, and dried to obtain concentrated sulfuric acid-modified molybdenum disulfide.

[0064] S2. Mix the silane coupling agent and deionized water in a mass ratio of 1:5, adjust the pH to 4 with acetic acid, hydrolyze for 35 minutes, and collect the hydrolyzed silane coupling agent.

[0065] S3, according to the ratio, the concentrated sulfuric acid modified molybdenum disulfide obtained in S1, sodium polystyrene sulfonate and 10 parts of deionized water were mixed, and ultrasonically dispersed at 800 rpm, and the hydrolyzed silane coupling agent obtained in S2 was added, and the mixture was heated to 50°C and stirred at 300 rpm to obtain a concentrated sulfuric acid modified molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent complex;

[0066] S4. According to the proportion, stir and mix the water-based epoxy resin, polyacrylic acid, and the remaining 20 parts of deionized water, add the concentrated sulfuric acid-modified molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent complex and the defoamer obtained in S3, and stir and mix to obtain component A.

[0067] The step of preparing component B comprises: separately packaging the water-based amine curing agent to obtain component B.

[0068] Comparative Example 1

[0069] A coating comprising component A and component B;

[0070] In parts by mass, the raw materials of component A include: 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 parts of defoaming agent, and 20 parts of deionized water;

[0071] The raw material composition of component B is a water-based amine curing agent.

[0072] in,

[0073] The preparation steps of component A include: mixing water-based epoxy resin with sodium polystyrene sulfonate, silane coupling agent, polyacrylic acid, defoaming agent and deionized water according to a proportion, and mixing to obtain component A.

[0074] The step of preparing component B comprises: separately packaging the water-based amine curing agent to obtain component B.

[0075] Comparative Example 2

[0076] A coating comprising component A and component B;

[0077] In parts by mass, the raw materials of component A include: 40 parts of waterborne epoxy resin, 8 parts of concentrated sulfuric acid-modified molybdenum disulfide, 2 parts of silane coupling agent, 3 parts of polyacrylic acid, 0.5 parts of defoaming agent, and 20 parts of deionized water;

[0078] The raw material composition of component B is a water-based amine curing agent.

[0079] in,

[0080] The preparation steps of component A include:

[0081] S1. Molybdenum disulfide powder and concentrated sulfuric acid were mixed in a mass ratio of 1:1, stirred and reacted at 60°C for 2h, centrifuged and washed until neutral, and dried to obtain concentrated sulfuric acid-modified molybdenum disulfide.

[0082] S2. Mix the silane coupling agent and deionized water in a mass ratio of 1:3, adjust the pH to 4 with acetic acid, hydrolyze for 30 minutes, and collect the hydrolyzed silane coupling agent.

[0083] S3. According to the ratio, the concentrated sulfuric acid-modified molybdenum disulfide obtained in S1 and 10 parts of deionized water were mixed, and ultrasonic dispersion was performed at 800 rpm to uniformly disperse the mixture. The hydrolyzed silane coupling agent obtained in S2 was added, and the mixture was heated to 50°C and stirred at 300 rpm to react. The solid product A was collected.

[0084] S4. According to the proportion, stir and mix the water-based epoxy resin, polyacrylic acid, and the remaining 10 parts of deionized water, add the solid product A obtained in S3 and the defoamer, and stir and mix to obtain component A.

[0085] The step of preparing component B comprises: separately packaging the water-based amine curing agent to obtain component B.

[0086] Comparative Example 3

[0087] A coating comprising component A and component B;

[0088] In parts by mass, the raw materials of component A include: 40 parts of waterborne epoxy resin, 8 parts of concentrated sulfuric acid-modified molybdenum disulfide, 2 parts of sodium polystyrene sulfonate, 3 parts of polyacrylic acid, 0.5 parts of defoaming agent, and 20 parts of deionized water;

[0089] The raw material composition of component B is a water-based amine curing agent.

[0090] in,

[0091] The preparation steps of component A include:

[0092] S1. Molybdenum disulfide powder and concentrated sulfuric acid were mixed in a mass ratio of 1:1, stirred and reacted at 60°C for 2h, centrifuged and washed until neutral, and dried to obtain concentrated sulfuric acid-modified molybdenum disulfide.

[0093] S2. According to the ratio, the concentrated sulfuric acid-modified molybdenum disulfide obtained in S1, sodium polystyrene sulfonate and 10 parts of deionized water were mixed, and ultrasonically dispersed at 800 rpm to obtain a solid product B.

[0094] S3. According to the proportion, stir and mix the water-based epoxy resin, polyacrylic acid, and the remaining 10 parts of deionized water, add the solid product B obtained in S2 and the defoamer, and stir and mix to obtain component A.

[0095] The step of preparing component B comprises: separately packaging the water-based amine curing agent to obtain component B.

[0096] The coatings obtained in Examples 1-3 and Comparative Examples 1-3 were subjected to corrosion resistance and mechanical property tests. Sample preparation: The coating was stirred for 5 minutes until uniform at a mass ratio of Component A:Component B of 100:20. The coating was then sprayed onto the surface of a cast iron substrate to prepare the corresponding sample. The sample was cured at 60°C for 4 hours, with the coating thickness controlled to approximately 120 μm.

[0097] 1. Acid resistance test: refer to GB / T9274, put the sample into 10% H2SO4 chemical reagent, and record the appearance of the immersed sample once a day to check whether the coating is complete, whether there is blistering, and whether there is falling off. Keep it for 1500 hours. The cut-off time of the process is based on the occurrence of blistering, falling off, cracking and other adverse conditions.

[0098] 2. Alkali resistance test: refer to GB / T9274, put the sample into 10% NaOH chemical reagent, and record the appearance of the immersed sample once a day to check whether the coating is complete, whether there is blistering, and whether there is falling off. Keep it for 1500 hours. The cut-off time of the process is based on the occurrence of blistering, falling off, cracking and other adverse conditions.

[0099] 3. Salt spray resistance test: refer to GB / T1771, use a blade to scratch a cross on the sample, place it in a salt spray test chamber, open the salt spray test chamber, and observe whether the paint film around the cross is bubbling, falling off, or cracking after 1500 hours.

[0100] 4. Abrasion resistance: Refer to GB / T 1768 and test under the conditions of 1000g / 1000 revolutions to obtain the mass loss value.

[0101] The test results are shown in the following table:

[0102]

[0103] It can be seen from the above test results that Examples 1-3 have excellent corrosion resistance and wear resistance.

[0104] The formulation systems of Comparative Examples 1-3 were unable to form concentrated sulfuric acid-modified molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent composites, resulting in the corrosion resistance and wear resistance of their coatings being worse than those of Examples 1-3.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, 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 parts by mass, the raw materials of component A include: 40-50 parts of waterborne epoxy resin, 5-8 parts of concentrated sulfuric acid-modified 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; The concentrated sulfuric acid modified molybdenum disulfide treatment process includes: mixing molybdenum disulfide powder and concentrated sulfuric acid in 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 concentrated sulfuric acid modified molybdenum disulfide.

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 concentrated sulfuric acid-modified molybdenum disulfide is modified with molybdenum disulfide having a particle size of 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 50,000-70,000 Da.

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

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: Concentrated sulfuric acid-modified molybdenum disulfide, sodium polystyrene sulfonate, and a portion of water are mixed according to a ratio, ultrasonically dispersed, and the hydrolyzed silane coupling agent is added, heated and stirred for reaction to obtain a concentrated sulfuric acid-modified molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent complex; Step 2: Mix the water-based epoxy resin, polyacrylic acid, and the remaining water according to the ratio, add the concentrated sulfuric acid-modified molybdenum disulfide@sodium polystyrene sulfonate@silane coupling agent complex and the defoamer obtained in Step 1, and stir 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 hydrolysis process of the silane coupling agent comprises: mixing the silane coupling agent and water in 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.

9. 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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