Bridge steel structure anticorrosive coating and preparation method thereof

Abstract

This application relates to an anti-corrosion coating for bridge steel structures and its preparation method, belonging to the field of bridge construction. The anti-corrosion coating for bridge steel structures comprises the following substances in parts by weight: 70-80 parts epoxy resin, 10-18 parts epoxy resin curing agent, 30-50 parts water, 3-6 parts graphene, 0.05-1 part defoamer, 0.03-0.08 parts dispersant, 0.04-0.08 parts leveling agent, and 8-12 g zinc phosphate. The combined effect of graphene and zinc phosphate in this application makes corrosion of the steel structure less likely to occur, thereby reducing the impact of corrosion on the service life of the steel structure; the method of this application has the advantage of simple process.

Description

Technical Field

[0001] This application relates to the field of bridge construction, and in particular to an anti-corrosion coating for bridge steel structures and its preparation method. Background Technology

[0002] Bridge engineering is an important component of national transportation engineering. With the rapid development of bridge engineering in my country in recent years, steel structures have been widely used in bridge construction. Steel structures have advantages such as simple construction, short construction period, low investment, and aesthetic appeal. However, steel structures still have a significant drawback—extremely poor corrosion resistance. Therefore, corrosion protection of steel structures has become a key focus in bridge engineering.

[0003] In practical use, most steel structure bridge projects face the test of the marine environment. As we all know, the marine environment is an extremely harsh corrosive environment. Seawater contains high concentrations of chlorides and sulfides, which easily combine with water vapor to form strong acids, thus exerting a strong corrosive effect on steel structure bridge projects and affecting the service life of the steel structure. Summary of the Invention

[0004] In order to make steel structures less susceptible to corrosion and thus less likely to affect their service life, this application provides an anti-corrosion coating for bridge steel structures and its preparation method.

[0005] Firstly, this application provides an anti-corrosion coating for bridge steel structures, which relates to the following technical solution:

[0006] A bridge steel structure anti-corrosion coating comprises the following substances in parts by weight: 70-80 parts epoxy resin, 10-18 parts epoxy resin curing agent, 30-50 parts water, 3-6 parts graphene, 0.05-1 part defoamer, 0.03-0.08 parts dispersant, 0.04-0.08 parts leveling agent, and 8-12 g zinc phosphate.

[0007] By adopting the above technical solution, this application utilizes the small size effect and special two-dimensional sheet structure of graphene to fill the pores and defects of the coating, forming a dense, layered barrier layer that prevents corrosive media from entering the substrate, thus making corrosion less likely to occur. Furthermore, the addition of zinc phosphate causes zinc and phosphate ions to undergo a redox reaction with the metal substrate, generating a Me(metal)-Zn-P2O5 phosphate film. This phosphate film is dense and has strong adhesion, adhering to the steel structure surface and isolating it from corrosive media, further reducing the likelihood of corrosion and minimizing its impact on the service life of the steel structure.

[0008] Optionally, the anti-corrosion coating may further include 6-10 parts of a pore-filling agent, wherein the pore-filling agent comprises sodium silicate and activated carbon, and the mass ratio of sodium silicate to activated carbon is 2:1.

[0009] By adopting the above technical solution, when corroded pores appear on the surface of the coating, sodium silicate reacts with acidic substances in seawater to generate silica gel. This silica gel accumulates on the surface of activated carbon or in the pores of activated carbon, sealing the pores on the surface of the coating. This makes it difficult for seawater to penetrate the pores of the activated carbon or the coating surface and continue to erode into the interior of the coating.

[0010] Optionally, the pore-blocking agent is prepared by dissolving sodium silicate in water, placing activated carbon into the sodium silicate aqueous solution for adsorption to obtain a mixture, and drying the mixture to obtain the pore-blocking agent.

[0011] By adopting the above technical solution, the pore-blocking agent prepared by this method has some sodium silicate located inside the activated carbon and some located on the surface of the activated carbon. Thus, when the pore-blocking agent comes into contact with seawater, the sodium silicate located on the surface can block the pores of the carbon on the coating surface and the surface of the activated carbon after contacting the water. The sodium silicate located in the pores of the activated carbon can block the pores of the activated carbon after contacting the water, thereby making it difficult for seawater to continue to diffuse into the interior of the coating through the activated carbon.

[0012] Optionally, the anti-corrosion coating further includes a pore-filling agent in the form of 9-15 parts by weight, wherein the pore-filling agent includes sodium silicate, activated carbon, and a bactericide, and the mass ratio of sodium silicate, activated carbon, and bactericide is 2:1:1.

[0013] By adopting the above technical solution, the addition of bactericide allows the bactericide to kill the microorganisms remaining in the seawater after seawater enters the pores of the coating surface, thus making it difficult for microorganisms to continue to corrode the coating.

[0014] Optionally, the pore-blocking agent is prepared by dissolving sodium silicate and bactericide in water to obtain a pre-prepared solution, placing activated carbon into the pre-prepared solution for adsorption to obtain a mixture, and drying the mixture to obtain the pore-blocking agent.

[0015] By adopting the above technical solution, the method for preparing the plugging hole in this application has the advantage of simple process.

[0016] Optionally, the graphene is hydroxyl-modified graphene.

[0017] By adopting the above technical solution, hydroxyl-modified graphene makes the graphene surface rich in hydroxyl groups, which on the one hand improves the uniformity of graphene distribution in the coating, and on the other hand, the hydroxyl groups on the graphene surface complex with the phosphating film formed by zinc phosphate, thereby making some graphene form a dense graphene film on the side of the phosphating film away from the substrate, so as to further make the substrate less susceptible to corrosion.

[0018] Hydroxyl-modified graphene was prepared by the following method: 180 mL of concentrated sulfuric acid, 20 mL of phosphoric acid, and 1.5 g of powdered graphite were added to a flask. Then, 10 g of potassium permanganate was slowly added under ice bath conditions. The mixture was stirred at 50 °C for 12 h to obtain the reactant. The reactant was slowly poured into a beaker containing 800 mL of ice, and 3 mL of hydrogen peroxide was added. After standing for 12 h, 20 mL of hydrochloric acid was added. The mixture was repeatedly washed with deionized water until pH = 7, and then centrifuged to obtain a black paste. This paste was diluted with water to obtain a 0.3% (w / w) graphene oxide dispersion.

[0019] 150 mL of graphene oxide dispersion was placed in a rotary evaporator flask, and 200 mL of glycerol and 250 mL of anhydrous ethanol were added. The mixture was evaporated under reduced pressure at 90 °C to remove water and obtain a mixture. This mixture was then transferred to a flask, and 60 mL of thionyl chloride was slowly added dropwise in multiple portions under ice bath conditions. The mixture was then slowly heated to 50 °C in an oil bath and reacted for 3 hours. The product was then evaporated at 78 °C to remove excess thionyl chloride. Finally, the product was washed with plenty of distilled water to remove excess glycerol, yielding hydroxyl-modified graphene. All reagents used were of analytical grade.

[0020] Optionally, the anti-corrosion coating may further include 7-13 parts by weight of zinc powder.

[0021] By adopting the above technical solution, the addition of zinc powder plays a role in filling gaps in the phosphating film of zinc phosphate, thereby further improving the anti-corrosion effect of the coating. The reason is that, on the one hand, zinc is more reactive than iron and easily loses electrons. In the early stage of corrosion, zinc powder and steel structure form a galvanic cell, with zinc as the anode and iron as the cathode. The current flows from zinc to iron, and the steel structure is cathodically protected. On the other hand, zinc powder is continuously corroded during application, and corrosion products, namely basic zinc carbonate, are deposited on the surface of zinc powder and steel. Its structure is dense and non-conductive. It is a stable compound that is difficult to dissolve and can block and shield the erosion of corrosive media, thus playing a role in corrosion prevention.

[0022] Secondly, this application proposes a method for preparing an anti-corrosion coating for bridge steel structures, involving the following technical solution: A method for preparing an anti-corrosion coating for bridge steel structures, comprising the following steps:

[0023] S1. Weigh each component according to its mass fraction;

[0024] S2. Mix epoxy resin and water evenly to obtain the first premix, and mix the remaining materials evenly to obtain the second premix;

[0025] S3. After mixing the first premix and the second premix evenly, the product is obtained.

[0026] By adopting the above technical solution, the preparation method of the anti-corrosion coating of this application has the advantage of simple process.

[0027] In summary, this application includes at least one of the following beneficial technical effects:

[0028] 1. The anti-corrosion coating of this application utilizes the small size effect and special two-dimensional sheet structure of graphene to fill the pores and defects of the coating, forming a dense, layered barrier layer that prevents corrosive media from entering the substrate, thus making corrosion less likely to occur. Furthermore, the addition of zinc phosphate causes zinc and phosphate ions to undergo a redox reaction with the metal substrate, generating a Me(metal)-Zn-P2O5 phosphate film. This phosphate film is dense and has strong adhesion, adhering to the steel structure surface and isolating it from corrosive media, further reducing the likelihood of corrosion and minimizing its impact on the service life of the steel structure.

[0029] 2. The preparation method of the anti-corrosion coating of this application has the advantage of simple process. Detailed Implementation

[0030] The present application will be further described in detail below with reference to preparation examples, embodiments and comparative examples;

[0031] In this embodiment, the epoxy resin was purchased from Shanghai Xumiao Chemical Co., Ltd. as 6520-WH-53A epoxy resin; the epoxy resin curing agent was purchased from Shanghai Xumiao Chemical Co., Ltd. as 8538-Y-68 curing agent; the defoamer was purchased from Shenzhen Longdi Chemical Co., Ltd. as BYK-071; the dispersant was purchased from Greenlink (Jining) Chemical Technology Co., Ltd. as BYK-220S; the leveling agent was purchased from Shanghai Buding Chemical as BYK-345; and the bactericide was polyhexamethylene guanidine, purchased from Tianjin Kewei Jinhong Environmental Protection Technology Co., Ltd.

[0032] Preparation Example 1

[0033] Dissolve 4 kg of sodium silicate in water, and add 2 kg of activated carbon to the sodium silicate aqueous solution for adsorption to obtain a mixture. After drying the mixture, the pore-blocking agent can be obtained.

[0034] Preparation Example 2

[0035] Dissolve 4 kg of sodium silicate and 2 kg of bactericide in water to obtain a pre-prepared solution. Add 3 kg of activated carbon to the pre-prepared solution for adsorption to obtain a mixture. After drying the mixture, the pore-blocking agent can be obtained.

[0036] Example 1

[0037] A method for preparing an anti-corrosion coating for bridge steel structures includes the following steps:

[0038] S1. Weigh the following substances: 70 kg epoxy resin, 30 kg water, 10 kg epoxy resin curing agent, 3 kg graphene, 0.05 kg defoamer, 0.03 kg dispersant, 0.04 kg leveling agent, and 8 kg zinc phosphate;

[0039] S2. Mix epoxy resin and water evenly to obtain a first premix, and mix the remaining materials evenly to obtain a second premix; S3. Mix the first premix and the second premix evenly to obtain the product.

[0040] Example 2

[0041] A method for preparing an anti-corrosion coating for bridge steel structures includes the following steps:

[0042] S1. Weigh the following substances: 80 kg epoxy resin, 50 kg water, 18 kg epoxy resin curing agent, 6 kg graphene, 1 kg defoamer, 0.08 kg dispersant, 0.08 kg leveling agent, and 12 kg zinc phosphate;

[0043] S2. Mix epoxy resin and water evenly to obtain a first premix, and mix the remaining materials evenly to obtain a second premix; S3. Mix the first premix and the second premix evenly to obtain the product.

[0044] Example 3

[0045] A method for preparing an anti-corrosion coating for bridge steel structures includes the following steps:

[0046] S1. Weigh the following substances: 75 kg epoxy resin, 40 kg water, 14 kg epoxy resin curing agent, 5 kg graphene, 0.07 kg defoamer, 0.06 kg dispersant, 0.06 kg leveling agent, and 10 kg zinc phosphate.

[0047] S2. Mix epoxy resin and water evenly to obtain a first premix, and mix the remaining materials evenly to obtain a second premix; S3. Mix the first premix and the second premix evenly to obtain the product.

[0048] Example 4

[0049] The difference between this embodiment and Embodiment 3 is that the graphene is hydroxylated graphene.

[0050] Example 5

[0051] A method for preparing an anti-corrosion coating for bridge steel structures includes the following steps:

[0052] S1. Weigh the following substances: 75 kg of epoxy resin, 40 kg of water, 14 kg of epoxy resin curing agent, 5 kg of graphene, 0.07 kg of defoamer, 0.06 kg of dispersant, 0.06 kg of leveling agent, 10 kg of zinc phosphate, and 6 kg of the plugging agent prepared in Example 1.

[0053] S2. Mix epoxy resin and water evenly to obtain a first premix, and mix the remaining materials evenly to obtain a second premix; S3. Mix the first premix and the second premix evenly to obtain the product.

[0054] Example 6

[0055] A method for preparing an anti-corrosion coating for bridge steel structures includes the following steps:

[0056] S1. Weigh the following substances: 75 kg of epoxy resin, 40 kg of water, 14 kg of epoxy resin curing agent, 5 kg of graphene, 0.07 kg of defoamer, 0.06 kg of dispersant, 0.06 kg of leveling agent, 10 kg of zinc phosphate, and 12 kg of the plugging agent prepared in Example 1.

[0057] S2. Mix epoxy resin and water evenly to obtain a first premix, and mix the remaining materials evenly to obtain a second premix; S3. Mix the first premix and the second premix evenly to obtain the product.

[0058] Example 7

[0059] A method for preparing an anti-corrosion coating for bridge steel structures includes the following steps:

[0060] S1. Weigh the following substances: 75 kg of epoxy resin, 40 kg of water, 14 kg of epoxy resin curing agent, 5 kg of graphene, 0.07 kg of defoamer, 0.06 kg of dispersant, 0.06 kg of leveling agent, 10 kg of zinc phosphate, and 9 kg of the plugging agent prepared in Example 1.

[0061] S2. Mix epoxy resin and water evenly to obtain a first premix, and mix the remaining materials evenly to obtain a second premix; S3. Mix the first premix and the second premix evenly to obtain the product.

[0062] Example 8

[0063] A method for preparing an anti-corrosion coating for bridge steel structures includes the following steps:

[0064] S1. Weigh the following substances: 75 kg of epoxy resin, 40 kg of water, 14 kg of epoxy resin curing agent, 5 kg of graphene, 0.07 kg of defoamer, 0.06 kg of dispersant, 0.06 kg of leveling agent, 10 kg of zinc phosphate, and 9 kg of the plugging agent prepared in Example 2.

[0065] S2. Mix epoxy resin and water evenly to obtain a first premix, and mix the remaining materials evenly to obtain a second premix; S3. Mix the first premix and the second premix evenly to obtain the product.

[0066] Example 9

[0067] A method for preparing an anti-corrosion coating for bridge steel structures includes the following steps:

[0068] S1. Weigh the following substances: 75 kg epoxy resin, 40 kg water, 14 kg epoxy resin curing agent, 5 kg graphene, 0.07 kg defoamer, 0.06 kg dispersant, 0.06 kg leveling agent, 10 kg zinc phosphate, and 7 kg zinc powder.

[0069] S2. Mix epoxy resin and water evenly to obtain a first premix, and mix the remaining materials evenly to obtain a second premix; S3. Mix the first premix and the second premix evenly to obtain the product.

[0070] Example 10

[0071] A method for preparing an anti-corrosion coating for bridge steel structures includes the following steps:

[0072] S1. Weigh the following substances: 75 kg epoxy resin, 40 kg water, 14 kg epoxy resin curing agent, 5 kg graphene, 0.07 kg defoamer, 0.06 kg dispersant, 0.06 kg leveling agent, 10 kg zinc phosphate, and 13 kg zinc powder.

[0073] S2. Mix epoxy resin and water evenly to obtain a first premix, and mix the remaining materials evenly to obtain a second premix; S3. Mix the first premix and the second premix evenly to obtain the product.

[0074] Example 11

[0075] A method for preparing an anti-corrosion coating for bridge steel structures includes the following steps:

[0076] S1. Weigh the following substances: 75 kg epoxy resin, 40 kg water, 14 kg epoxy resin curing agent, 5 kg graphene, 0.07 kg defoamer, 0.06 kg dispersant, 0.06 kg leveling agent, 10 kg zinc phosphate, and 10 kg zinc powder.

[0077] S2. Mix epoxy resin and water evenly to obtain a first premix, and mix the remaining materials evenly to obtain a second premix; S3. Mix the first premix and the second premix evenly to obtain the product.

[0078] Example 12

[0079] A method for preparing an anti-corrosion coating for bridge steel structures includes the following steps:

[0080] S1. Weigh the following substances: 75 kg epoxy resin, 40 kg water, 14 kg epoxy resin curing agent, 5 kg graphene, 0.07 kg defoamer, 0.06 kg dispersant, 0.06 kg leveling agent, 10 kg zinc phosphate, 9 kg pore-blocking agent and 10 kg zinc powder obtained in Example 1.

[0081] S2. Mix epoxy resin and water evenly to obtain a first premix, and mix the remaining materials evenly to obtain a second premix; S3. Mix the first premix and the second premix evenly to obtain the product.

[0082] Example 13

[0083] A method for preparing an anti-corrosion coating for bridge steel structures includes the following steps:

[0084] S1. Weigh the following substances: 75 kg of epoxy resin, 40 kg of water, 14 kg of epoxy resin curing agent, 5 kg of graphene, 0.07 kg of defoamer, 0.06 kg of dispersant, 0.06 kg of leveling agent, 10 kg of zinc phosphate, 9 kg of plugging agent and 10 kg of zinc powder obtained in Example 2.

[0085] S2. Mix epoxy resin and water evenly to obtain a first premix, and mix the remaining materials evenly to obtain a second premix; S3. Mix the first premix and the second premix evenly to obtain the product.

[0086] Comparative Example 1

[0087] A method for preparing an anti-corrosion coating for bridge steel structures includes the following steps:

[0088] S1. Weigh the following substances: 75 kg epoxy resin, 40 kg water, 14 kg epoxy resin curing agent, 5 kg graphene, 0.07 kg defoamer, 0.06 kg dispersant, and 0.06 kg leveling agent;

[0089] S2. Mix epoxy resin and water evenly to obtain a first premix, and mix the remaining materials evenly to obtain a second premix; S3. Mix the first premix and the second premix evenly to obtain the product.

[0090] Comparative Example 2

[0091] A method for preparing an anti-corrosion coating for bridge steel structures includes the following steps:

[0092] S1. Weigh the following substances: 75 kg epoxy resin, 40 kg water, 14 kg epoxy resin curing agent, 0.07 kg defoamer, 0.06 kg dispersant, 0.06 kg leveling agent, and 10 kg zinc phosphate;

[0093] S2. Mix epoxy resin and water evenly to obtain a first premix, and mix the remaining materials evenly to obtain a second premix; S3. Mix the first premix and the second premix evenly to obtain the product.

[0094] Performance testing

[0095] According to standard HG / T 4759-2014, the products prepared in Examples 1-13 and Comparative Examples 1-2 were tested for salt spray resistance, acid resistance, cross-cut adhesion test and impact resistance; according to GB / T9274-1988, the products prepared in Examples 1-13 and Comparative Examples 1-2 were tested for seawater resistance, and the test results are recorded in Table 1.

[0096] Table 1

[0097]

[0098]

[0099]

[0100]

[0101] As can be seen from Example 1, Comparative Examples 1 and 2, and Table 1, the use of graphene in combination with zinc phosphate in Example 1 significantly improved the performance of the coating. This is because graphene can fill the pores and defects in the coating and form an insulating layer to prevent corrosive media from entering the substrate. The addition of zinc phosphate reacts with the metal substrate to form a phosphate film. The phosphate film adheres to the surface of the steel structure, making it difficult for corrosive media to contact the steel structure surface and corrode the steel structure. The combined use of graphene and zinc phosphate isolates the metal substrate from the corrosive media, thus making the steel structure surface less susceptible to corrosion.

[0102] Combining Examples 3 and 4 with Table 1, it can be seen that Example 4 uses hydroxyl-modified graphene, while Example 3 uses graphene. Compared with Example 3, the coating prepared in Example 4 has better impact resistance and artificial seawater resistance. This is because the hydroxyl-modified graphene complexes with the phosphate film formed by zinc phosphate, thereby improving the bonding strength between the hydroxyl-modified graphene and the phosphate film. At the same time, it allows the hydroxyl-modified graphene to form a dense graphene film on the side of the phosphate film away from the substrate, further making the substrate less susceptible to corrosion.

[0103] As can be seen from Examples 4 and 5 and Table 1, the addition of the pore-blocking agent in Example 5 further makes the substrate less susceptible to corrosion. This is because when pores appear on the surface of the coating, the sodium silicate in the pore-blocking agent reacts with acidic substances in the seawater to form silica gel. This silica gel accumulates on the surface of activated carbon or in the pores of activated carbon, sealing the pores on the surface of the coating. This makes it difficult for seawater to pass through the pores on the surface of the coating and continue to move into the interior of the coating, thus preventing corrosion of the coating and the substrate.

[0104] Combining Examples 4 and 9 with Table 1, it can be seen that the addition of zinc powder in Example 9 makes the coating more resistant to artificial seawater. The reason is that the addition of zinc powder plays a cathodic protection role for the substrate.

[0105] As can be seen from Examples 12, 4, 9 and 5 and Table 1, the combined use of zinc powder and pore-blocking agent in Example 12 further improved the coating's impact resistance and resistance to artificial seawater.

[0106] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A type of anti-corrosion coating for bridge steel structures, characterized in that, The coating comprises the following components by weight: 70-80 parts epoxy resin, 30-50 parts water, 10-18 parts epoxy resin curing agent, 3-6 parts graphene, 0.05-1 part defoamer, 0.03-0.08 parts dispersant, 0.04-0.08 parts leveling agent, and 8-12 parts zinc phosphate. The anti-corrosion coating also includes 6-12 parts of a pore-filling agent, which comprises sodium silicate and activated carbon, with a mass ratio of sodium silicate to activated carbon of 2:

1. The pore-filling agent is prepared by dissolving sodium silicate in water, immersing activated carbon in the sodium silicate aqueous solution for adsorption to obtain a mixture, and drying the mixture to obtain the pore-filling agent. The graphene is hydroxyl-modified graphene.

2. A type of anti-corrosion coating for bridge steel structures, characterized in that, The coating comprises the following components by weight: 70-80 parts epoxy resin, 30-50 parts water, 10-18 parts epoxy resin curing agent, 3-6 parts graphene, 0.05-1 part defoamer, 0.03-0.08 parts dispersant, 0.04-0.08 parts leveling agent, and 8-12 parts zinc phosphate. The anti-corrosion coating also includes 9-15 parts by weight of a pore-blocking agent, comprising sodium silicate, activated carbon, and a bactericide, wherein the mass ratio of sodium silicate, activated carbon, and bactericide is 2:1:

1. The pore-blocking agent is prepared by dissolving sodium silicate and bactericide in water to obtain a pre-prepared solution, placing activated carbon into the pre-prepared solution for adsorption to obtain a mixture, and drying the mixture to obtain the pore-blocking agent.

3. A bridge steel structure anti-corrosion coating according to claim 1 or 2, characterized in that, The anti-corrosion coating also includes 7-13 parts by weight of zinc powder.

4. A method for preparing the anti-corrosion coating for bridge steel structures according to claim 3, characterized in that, Includes the following steps: S1. Weigh each component according to its mass fraction; S2. Mix epoxy resin and water evenly to obtain the first premix, and mix the remaining materials evenly to obtain the second premix; S3. After mixing the first premix and the second premix evenly, the product is obtained.

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