Self-repairing coating for tower grounding metal as well as preparation method and application of self-repairing coating

Abstract

The invention belongs to the technical field of coatings, and particularly discloses a self-repairing coating for tower grounding metal as well as a preparation method and application of the self-repairing coating. The high-temperature-resistant and anti-corrosion self-repairing coating comprises a first component and a second component, the first component is prepared from the following components in parts by weight: 20 to 90 parts of novolac epoxy resin, 3 to 5 parts of aniline trapezoid polysilsesquioxane, 5 to 8 parts of red lead, 6 to 9 parts of wollastonite, 20 to 40 parts of self-repairing material, 1 to 3 parts of dispersing agent and 3 to 6 parts of polyamide; the second component comprises the following components in parts by weight: 15-20 parts of a curing agent; wherein the aniline trapezoid polysilsesquioxane is formed by phenyl trapezoid polysilsesquioxane in an aniline mode. The coating is suitable for corrosion protection of metal components exposed in high-temperature, salt and humid environments for a long time.

Description

Technical Field

[0001] The present invention belongs to the technical field of coatings, and particularly relates to a self-healing coating for tower grounding metal, a preparation method thereof, and an application thereof. Background Art

[0002] The corrosion problem of tower grounding materials is one of the important issues that the power system has long been concerned about. The grounding materials are buried in the soil for a long time and are easily corroded, which affects their electrical conductivity and service life. Common grounding materials include flat steel, round steel, galvanized steel, copper, and copper-clad steel, etc., but these materials generally have the problem of insufficient corrosion resistance. The corrosion of the grounding metal material will cause a layer of corrosion products with high resistivity to adhere to its surface, which will affect the normal current dissipation process of the grounding electrode, increase the grounding resistance, and reduce the grounding performance. The presence of the corrosion product layer will change the dissipation current distribution, grounding resistance, surface potential, and step voltage distribution of the grounding electrode, thereby affecting the power supply reliability of the transmission line and the safe operation of the power system. The conventional anti-corrosion method of metal coatings is to coat the paint on the metal surface to prevent the direct contact between the metal and the corrosive medium, which can only play a simple physical barrier role, and cannot actively prevent corrosion according to the specific corrosion situation, and cannot really effectively reduce the corrosion of the metal.

[0003] Generally speaking, corrosion inhibitors are added to the paint, but the corrosion inhibitors will gradually lose after the paint is coated, reducing the anti-corrosion effect. Even the corrosion inhibitors will interact with the base paint, weakening the effect of the corrosion inhibitor, and the metal material will still be affected by the surrounding medium and corrode. During long-term use, damage or cracking will occur, thus exposing the metal to the corrosive environment.

[0004] Tetrahedral polyhedral oligomeric silsesquioxane was first prepared by phenyltrichlorosilane through simple hydrolysis and the "thermal equilibrium polycondensation method", and is considered to be a polymer that "spontaneously" forms a regular double-chain structure. Among the tetrahedral polyhedral oligomeric silsesquioxanes with various substituents, the phenyl tetrahedral polyhedral oligomeric silsesquioxane has a semi-rigid structure. This rigid-flexible structure not only ensures its good flexibility and tensile strength but also has good solubility. Introducing it into the coating material can improve the coating performance by utilizing the anti-aging performance of polysiloxane and the high-temperature resistance of phenylsiloxane. However, the problem of poor compatibility between tetrahedral polyhedral oligomeric silsesquioxane and the resin matrix still cannot be effectively solved. Summary of the Invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a self-healing coating for tower grounding metal, a preparation method thereof, and an application thereof, which are suitable for the corrosion protection of metal components that are long-term exposed to high temperature, salt, and humid environments.

[0006] The purpose of the present invention can be achieved by the following technical solutions: In a first aspect, the present invention provides a self-healing coating for tower grounding metal, comprising a first component and a second component; Calculated by weight, the first component comprises 20-90 parts of phenolic epoxy resin, 3-5 parts of aniline-modified ladder polyhedral oligomeric silsesquioxane, 5-8 parts of red lead, 6-9 parts of wollastonite, 20-40 parts of self-healing material, 1-3 parts of dispersant, and 3-6 parts of polyamide; Calculated by weight, the second component comprises 15-20 parts of curing agent; The aniline-modified ladder polyhedral oligomeric silsesquioxane is formed by aniline modification of phenyl ladder polyhedral oligomeric silsesquioxane; The curing agent is an organosilicon-modified dendritic polyamide, and the preparation method of the organosilicon-modified dendritic polyamide is as follows: Prepare an acetone solution of trimellitic acid chloride, dropwise add bis-terminal amino silicone oil to the solution, heat and react for 6-8 hours, and perform suction filtration and washing to obtain.

[0007] Preferably, the molecular weight of the bis-terminal amino silicone oil is 400-600.

[0008] Preferably, the molar ratio of trimellitic acid chloride to terminal amino silicone oil is 1:1-2.

[0009] Preferably, the temperature of the heating reaction is 30-40 °C.

[0010] Phenolic epoxy resin has high stability and advantages such as heat resistance, acid resistance, alkali resistance, and wear resistance. The combination of phenolic epoxy resin and curing agent makes the coating have the advantages of traditional solvent-based phenolic epoxy coatings, and also has good flexibility, impact resistance, low VOC emissions, and good workability.

[0011] Preferably, the mass ratio of the curing agent to the aniline-modified ladder polyhedral oligomeric silsesquioxane is (3-5):1, and more preferably, the mass ratio of the curing agent to the aniline-modified ladder polyhedral oligomeric silsesquioxane is (3-4):1.

[0012] The total amount of the curing agent and the aniline-modified ladder polyhedral oligomeric silsesquioxane is limited within a certain range to avoid excessive curing materials affecting the coating performance. If the amount of the aniline-modified ladder polyhedral oligomeric silsesquioxane is too small, its effect is not obvious; if the amount of the aniline-modified ladder polyhedral oligomeric silsesquioxane is too large, the coating becomes brittle and the impact resistance becomes poor.

[0013] More preferably, the mass ratio of the aniline-modified ladder polyhedral oligomeric silsesquioxane to the curing agent of the second component is 4:1.

[0014] Preferably, the preparation method of the aniline-modified ladder polyhedral oligomeric silsesquioxane is as follows: Add phenyl ladder polysilsesquioxane to fuming nitric acid, stir at low temperature for 0.5 h, then stir at room temperature for 5 - 20 h, let it stand for precipitation and then dry. Dissolve the dried material in a solvent such as tetrahydrofuran or dioxane, add palladium-carbon catalyst, and react with formic acid at 50 - 80 °C for 1 - 5 h. After filtration, washing and drying, aniline-functionalized ladder polysilsesquioxane is obtained.

[0015] Preferably, the low temperature for the low-temperature stirring refers to -20 - 5 °C.

[0016] The reaction process for preparing aniline-functionalized ladder polysilsesquioxane is as follows: 。

[0017] The phenyl ladder polysilsesquioxane is purchased from Forsman Technology (Beijing) Co., Ltd.

[0018] Preferably, the molar ratio of the phenyl ladder polysilsesquioxane to the palladium-carbon catalyst is 1:(0.01 - 0.1).

[0019] Preferably, the molar ratio of the phenyl ladder polysilsesquioxane to the formic acid is 1:(1 - 2).

[0020] In the present invention, phenyl ladder polysilsesquioxane is nitrated and hydrogenated to prepare aniline-functionalized ladder polysilsesquioxane. The aniline group can react with the epoxy resin used in the coating, so that the aniline-functionalized ladder polysilsesquioxane can be evenly dispersed in the resin system, thus making full use of the characteristics of the aniline-functionalized ladder polysilsesquioxane.

[0021] Adding aniline-functionalized ladder polysilsesquioxane to the coating is beneficial to improving the high-temperature resistance, aging resistance and corrosion resistance of the coating. The Si-O-Si chemical bond in the aniline-functionalized ladder polysilsesquioxane is beneficial to improving the high-temperature resistance of the coating and has a certain retarding effect on combustion. In addition, the Si-O-Si chemical bond is resistant to aging and can effectively reduce the aging rate of phenolic epoxy resin in the natural environment, thus effectively maintaining the corrosion resistance. The rigid-flexible structure characteristics of the ladder polysilsesquioxane itself improve the hardness and impact resistance of the cured coating.

[0022] Aniline-functionalized ladder polysilsesquioxane has an amino group, that is, aniline-functionalized ladder polysilsesquioxane plays a role similar to that of a curing agent. Therefore, the content of aniline-functionalized ladder polysilsesquioxane in the coating should not be too high, otherwise it will cause premature curing of the phenolic epoxy resin in the first component.

[0023] Red lead and wollastonite play a role similar to that of color powder, have strong covering power, and red lead and wollastonite also have high antioxidant performance, high stability and corrosion resistance.

[0024] Preferably, the self-healing material is a composite microcapsule formed with tung oil and linseed oil as the core material and polyaniline as the shell material.

[0025] More preferably, the preparation method of the self-healing material is as follows: The core material and the emulsifier are rapidly stirred at 50 °C for 20 minutes, then deionized water is added and emulsified for 15 - 30 minutes to form a stable oil-in-water emulsion. Subsequently, aniline is added to the aqueous phase and adsorbed onto the oil-water interface due to the electrostatic interaction between the emulsifier and aniline. The aniline undergoes chemical oxidative polymerization to form a PANI shell, obtaining the self-healing material.

[0026] Preferably, the stirring speed after mixing the core material and the emulsifier is 300 - 1200 r / min.

[0027] Preferably, the emulsifier includes sodium lignosulfonate, and the mass of the emulsifier accounts for 1 - 7% of the mass of the core material.

[0028] Preferably, the mass ratio of the core material to the shell material is 1:1.

[0029] Preferably, the particle size of the self-healing material is 50 - 200 μm.

[0030] The principle of the self-healing material is as follows: The coating cures into a film. When cracks occur in the coating and the composite microcapsules rupture, the tung oil and linseed oil therein are released and filled in the cracks, and react with oxygen after contacting the air and solidify, realizing the autonomous repair of the coating cracks.

[0031] Preferably, the dispersant is an amphoteric dispersant, such as a high molecular polymer of phosphate ester salt type.

[0032] In a second aspect, the present invention provides a preparation method of a self-healing coating for tower grounding metal, and the preparation method includes the following steps: (1) Mix other raw materials except anilinized ladder-shaped polyhedral oligomeric silsesquioxane in the first component evenly, then grind and filter to obtain a uniform mixture; (2) Add anilinized ladder-shaped polyhedral oligomeric silsesquioxane to the mixture in step (1) and mix evenly to obtain the first component; (3) Before applying the coating, mix the first component with the second component to obtain a high-temperature resistant and corrosion-resistant self-healing coating.

[0033] In a third aspect, the present invention provides an application of a self-healing coating for tower grounding metal, and the application method is: applying the self-healing coating to the surface of a metal component to form a high-temperature resistant and corrosion-resistant coating.

[0034] The beneficial effects that can be produced by this application are as follows: The present invention combines the characteristics of anti-corrosion coating technology, self-healing technology and anilinized ladder-type polyhedral oligomeric silsesquioxane technology, comprehensively improving the anti-corrosion, high-temperature resistance and aging resistance of the coating. The preparation method of the present invention is simple, with low cost and is easy for mass production.

[0035] The present invention uses anilinized ladder-type polyhedral oligomeric silsesquioxane to improve the high-temperature resistance, aging resistance and anti-corrosion performance of the coating. The Si-O-Si chemical bond in anilinized ladder-type polyhedral oligomeric silsesquioxane is relatively resistant to high temperatures. Introducing the Si-O-Si chemical bond into the coating can improve the high-temperature resistance of the coating and has a certain retarding effect on combustion. The structure characteristics of anilinized ladder-type polyhedral oligomeric silsesquioxane, which combines rigidity and flexibility, can also improve the hardness and impact resistance of the coating. The aging resistance of anilinized ladder-type polyhedral oligomeric silsesquioxane can effectively reduce the aging rate of epoxy resin in the natural environment, thus effectively maintaining the anti-corrosion performance.

[0036] The curing agent of the present invention is organosilicon-modified dendritic polyamide. By introducing an organosilicon chain segment into the dendritic polyamide structure and introducing the Si-O-Si chemical bond, and also containing phenyl groups, it not only has good bonding with phenolic epoxy resin, but also has good bonding force with anilinized ladder-type polyhedral oligomeric silsesquioxane and is well dispersed with each other. Therefore, organosilicon-modified dendritic polyamide and anilinized ladder-type polyhedral oligomeric silsesquioxane can synergistically improve the high-temperature resistance and anti-corrosion performance of the coating.

[0037] The present invention uses a self-healing material. When cracks occur in the coating and cause the composite microcapsules to rupture, the tung oil and linseed oil therein are released and filled at the crack, and react with oxygen after contacting the air and solidify, realizing the autonomous repair of the coating cracks. Description of the Drawings

[0038] Figure 1 It is the molecular structure schematic diagram and nuclear magnetic resonance hydrogen spectrum data of the anilinized ladder-type polyhedral oligomeric silsesquioxane prepared in Example 1. Detailed Embodiments

[0039] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present application.

[0040] Example 1

[0041] Preparation of anilinized ladder polysilsesquioxane: 1 mol of phenyl ladder polysilsesquioxane (purchased from Forsman Technology (Beijing) Co., Ltd.) was added to 200 ml of fuming nitric acid and stirred at -10°C for 0.5 h, then stirred at room temperature for 5 h. After precipitation and drying, it was dissolved in dry tetrahydrofuran solvent, 0.01 mol of palladium-carbon catalyst was added, and 1 mol of formic acid was added at 80°C and reacted for 1 h. After filtration, washing and drying, anilinized ladder polysilsesquioxane was obtained. The schematic diagram of its molecular structure and the data of the proton nuclear magnetic resonance spectrum are as Figure 1 shown.

[0042] Preparation of self-healing material: The core material (the volume ratio of tung oil to linseed oil is 1:1) and the emulsifier sodium lignosulfonate were stirred at 500 r / min for 20 minutes at 50°C. The mass of sodium lignosulfonate is 2% of the mass of the core material. Then deionized water was added and emulsified for 15 minutes to form a stable oil-in-water emulsion. Subsequently, aniline was added to the aqueous phase, and the mass ratio of the core material to aniline is 1:1. Due to the electrostatic interaction between the emulsifier and aniline, it was adsorbed on the oil-water interface. Aniline was chemically oxidized and polymerized to form a PANI shell, and a self-healing material with a particle size of 50 - 200 μm was obtained.

[0043] Preparation of organosilicon-modified dendritic polyamide: Prepare an acetone solution of trimellitic acid trichloride, and drop bis-terminal amino silicone oil with a molecular weight of 400 - 600 into the solution. The molar ratio of trimellitic acid trichloride to terminal amino silicone oil is 1:1, and the reaction is carried out at 30°C for 7 hours. After suction filtration and washing, it is obtained.

[0044] Preparation of self-healing coating for pole tower grounding metal: (1) 20 parts by weight of phenolic epoxy resin (grade F-44), 5 parts by weight of red lead, 6 parts by weight of wollastonite, 20 parts by weight of self-healing material, 1 part by weight of dispersant (BYK DISPERBYK-103) and 3 parts by weight of polyamide (grade 650) were mixed evenly, then added to a grinding machine for grinding. After grinding, it was filtered to obtain a uniform mixture; (2) 3 parts by weight of anilinized ladder polysilsesquioxane was added to the mixture and stirred evenly to obtain a uniformly mixed first component; (3) Before coating, the first component was mixed with 15 parts by weight of curing agent (organosilicon-modified dendritic polyamide) of the second component to form a high-temperature resistant and corrosion-resistant self-healing coating.

[0045] The self-healing coating was sprayed on the surface of a sandblasted metal member (flat steel) to form a coating with a thickness of 0.2 mm. After the coating was cured, an EIS test was carried out according to the test standard ISO16773-2:2007. It could maintain good anti-corrosion performance after being immersed in 4.5 wt% NaCl solution for 50 days, and its Zf = 1.53×10 6Ωcm 2 After curing, the coating was heated at 650 °C for 2000 h, and no damage occurred on the metal surface, effectively protecting the metal components.

[0046] Example 2

[0047] Preparation of anilinized ladder polysilsesquioxane: 1 mol of phenyl ladder polysilsesquioxane (purchased from Forsman Technology (Beijing) Co., Ltd.) was added to 200 ml of fuming nitric acid and stirred at -20 °C for 0.5 h, then stirred at room temperature for 20 h. After precipitation and drying, it was dissolved in dry dioxane solvent, 0.1 mol of palladium-carbon catalyst was added, and 2 mol of formic acid was added at 50 °C and reacted for 5 h. After filtration, washing and drying, anilinized ladder polysilsesquioxane was obtained.

[0048] Preparation of self-healing material: The core material (tung oil and linseed oil with a volume ratio of 1:1) and the emulsifier sodium lignosulfonate were stirred at 50 °C at 1000 r / min for 20 minutes. The mass of sodium lignosulfonate was 5% of the mass of the core material. Then deionized water was added and emulsified for 25 minutes to form a stable oil-in-water emulsion. Subsequently, aniline was added to the aqueous phase, and the mass ratio of the core material to aniline was 1:1. Due to the electrostatic interaction between the emulsifier and aniline, it was adsorbed onto the oil-water interface. Aniline was chemically oxidized and polymerized to form a PANI shell, obtaining a self-healing material with a particle size of 50 - 200 μm.

[0049] Preparation of organosilicon-modified dendritic polyamide: Prepare an acetone solution of trimellitic acid trichloride, and drop bis-terminal amino silicone oil with a molecular weight of 400 - 600 into the solution. The molar ratio of trimellitic acid trichloride to terminal amino silicone oil is 1:2, and the reaction is carried out at 40 °C for 8 hours. After filtration and washing, it is obtained.

[0050] Preparation of self-healing coating for pole tower grounding metal: (1) 90 parts by weight of phenolic epoxy resin (grade F-44), 8 parts by weight of red lead, 9 parts by weight of wollastonite, 40 parts by weight of self-healing material, 3 parts by weight of dispersant (BYK DISPERBYK-103), and 6 parts by weight of polyamide (grade 650) were mixed evenly, then added to a grinder for grinding. After grinding, it was filtered to obtain a uniform mixture; (2) 5 parts by weight of anilinized ladder polysilsesquioxane was added to the mixture and stirred evenly to obtain a uniformly mixed first component; (3) Before coating, the first component was mixed with 20 parts by weight of curing agent (organosilicon-modified dendritic polyamide) of the second component to form a high-temperature resistant and corrosion-resistant self-healing coating.

[0051] The self-healing coating was sprayed on the surface of a sandblasted metal component (flat steel) to form a 0.2-mm-thick coating. After the coating was cured, an EIS test was conducted according to the test standard ISO16773-2:2007. It could maintain good anti-corrosion performance after being immersed in a 4.4 wt% NaCl solution for 50 days, and its Z f = 1.49×10 6 Ω·cm 2 . After the cured coating was heated at 660 °C for 1600 h, no damage occurred on the metal surface, and the metal component was effectively protected.

[0052] Example 3

[0053] Preparation of anilinized ladder-shaped polyhedral oligomeric silsesquioxane: 1 mol of phenyl ladder-shaped polyhedral oligomeric silsesquioxane (purchased from Forsman Technology (Beijing) Co., Ltd.) was added to 200 ml of fuming nitric acid and stirred at 5 °C for 0.5 h, then stirred at room temperature for 10 h. After precipitation and drying, it was dissolved in dry dioxane solvent, 0.05 mol of palladium-carbon catalyst was added, and 1.5 mol of formic acid was added at 60 °C and reacted for 2 h. After filtration, washing and drying, anilinized ladder-shaped polyhedral oligomeric silsesquioxane was obtained.

[0054] Preparation of self-healing material: The core material (tung oil and linseed oil with a volume ratio of 1:1) and the emulsifier sodium lignosulfonate were stirred at 1000 r / min for 20 minutes at 50 °C. The mass of sodium lignosulfonate was 5% of the mass of the core material. Then deionized water was added and emulsified for 25 minutes to form a stable oil-in-water emulsion. Subsequently, aniline was added to the aqueous phase. The mass ratio of the core material to aniline was 1:1. Due to the electrostatic interaction between the emulsifier and aniline, it was adsorbed onto the oil-water interface. Aniline was chemically oxidized and polymerized to form a PANI shell, and self-healing material with a particle size of 50 - 200 μm was obtained.

[0055] Preparation of organosilicon-modified dendritic polyamide: Prepare an acetone solution of trimesoyl chloride, and dropwise add bis(amino)-terminated silicone oil with a molecular weight of 400 - 600 to the solution. The molar ratio of trimesoyl chloride to amino-terminated silicone oil is 1:1.5, and react at 35 °C for 6 hours. After filtration and washing, it is obtained.

[0056] Preparation of self-healing coating for pole tower grounding metal: (1) 50 parts by weight of phenolic epoxy resin (grade F-44), 6 parts by weight of red lead, 7 parts by weight of wollastonite, 30 parts by weight of self-healing material, 2 parts by weight of dispersant (BYK DISPERBYK-103), and 4 parts by weight of polyamide (grade 650) were mixed evenly, then added to a grinder for grinding. After grinding, it was filtered to obtain a uniform mixture; (2) Add 4 parts by weight of anilinized ladder-shaped polyhedral oligomeric silsesquioxane to the mixture and stir evenly to obtain a uniformly mixed first component; (2) Before coating, mix 18 parts by weight of a curing agent (organosilicon-modified dendritic polyamide) of the first component and the second component to form a high-temperature resistant and corrosion-resistant self-healing coating.

[0057] Spray the self-healing coating on the surface of a sandblasted metal component (flat steel) to form a coating with a thickness of 0.2 mm. After the coating is cured, perform an EIS test according to the test standard ISO16773-2:2007. It can maintain good anti-corrosion performance after being immersed in a 4.3 wt% NaCl solution for 50 days, and its Zf = 1.45×10 6 Ω·cm 2 After the cured coating is heated at 650 °C for 1500 h, no damage occurs on the metal surface, and the metal component is effectively protected.

[0058] Example 4

[0059] Preparation of anilinized ladder-shaped polyhedral oligomeric silsesquioxane: Add 1 mol of phenyl ladder-shaped polyhedral oligomeric silsesquioxane (purchased from Forsman Technology (Beijing) Co., Ltd.) to 200 ml of fuming nitric acid and stir at -15 °C for 0.5 h, then stir at room temperature for 8 h. After precipitation and drying, dissolve it in dry tetrahydrofuran solvent, add 0.04 mol of palladium-carbon catalyst, add 1.2 mol of formic acid at 70 °C and react for 2 h, and then obtain anilinized ladder-shaped polyhedral oligomeric silsesquioxane after filtration, washing and drying.

[0060] Preparation of self-healing material: Stir the core material (the volume ratio of tung oil and linseed oil is 1:1) and the emulsifier sodium lignosulfonate at 50 °C at 800 r / min for 20 minutes. The mass of sodium lignosulfonate is 7% of the mass of the core material, then add deionized water and emulsify for 30 minutes to form a stable oil-in-water emulsion. Subsequently, add aniline to the water phase, and the mass ratio of the core material to aniline is 1:1. Due to the electrostatic interaction between the emulsifier and aniline, it is adsorbed on the oil-water interface, and aniline is chemically oxidized and polymerized to form a PANI shell, obtaining a self-healing material with a particle size of 50 - 200 μm.

[0061] Preparation of organosilicon-modified dendritic polyamide: Prepare an acetone solution of trimesoyl chloride, and add a bis-terminal amino silicone oil with a molecular weight of 400 - 600 dropwise to the solution. The molar ratio of trimesoyl chloride to the terminal amino silicone oil is 1:1.2, and react at 33 °C for 7 hours, then perform suction filtration and washing to obtain it.

[0062] Preparation of self-healing coating for tower grounding metal: (1) Mix 40 parts by weight of phenolic epoxy resin (grade F-44), 8 parts by weight of red lead, 9 parts by weight of wollastonite, 20 parts by weight of self-healing material, 3 parts by weight of dispersant (BYK DISPERBYK-103), and 6 parts of polyamide (grade 650) evenly, then add them to a grinding machine for grinding. After grinding, filter to obtain a homogeneous mixture; (2) Add 5 parts by weight of anilinized ladder-type polyhedral oligomeric silsesquioxane to the mixture and stir evenly to obtain a uniformly mixed first component; (3) Before coating, mix the first component with 16 parts by weight of a curing agent (organosilicon-modified dendritic polyamide) of the second component to form a high-temperature and corrosion-resistant self-healing coating.

[0063] Apply the self-healing coating on the surface of a sandblasted metal component (flat steel) by spraying to form a coating with a thickness of 0.2 mm. After the coating is cured, conduct an EIS test according to the test standard ISO16773-2:2007. It can maintain good anti-corrosion performance after being immersed in a 4.2 wt% NaCl solution for 50 days, and its Zf = 1.48×10 6 Ωcm 2 , After the cured coating is heated at 680 °C for 1660 h, the metal surface is not damaged, and the metal component is effectively protected.

[0064] Example 5

[0065] Preparation of anilinized ladder-type polyhedral oligomeric silsesquioxane: Add 1 mol of phenyl ladder-type polyhedral oligomeric silsesquioxane (purchased from Forsman Technology (Beijing) Co., Ltd.) to 200 ml of fuming nitric acid, stir at 0 °C for 0.5 h, then stir at room temperature for 9 h. After precipitation and drying, dissolve it in dry tetrahydrofuran solvent, add 0.04 mol of palladium-carbon catalyst, add 1.1 mol of formic acid at 70 °C and react for 2 h, then filter, wash and dry to obtain anilinized ladder-type polyhedral oligomeric silsesquioxane.

[0066] Preparation of self-healing material: Stir the core material (volume ratio of tung oil to linseed oil is 1:1) and emulsifier sodium lignosulfonate at 50 °C at 1200 r / min for 20 minutes. The mass of sodium lignosulfonate is 1% of the mass of the core material. Then add deionized water and emulsify for 20 minutes to form a stable oil-in-water emulsion. Subsequently, add aniline to the water phase. The mass ratio of the core material to aniline is 1:1. It is adsorbed to the oil-water interface due to the electrostatic interaction between the emulsifier and aniline. Aniline undergoes chemical oxidative polymerization to form a PANI shell, obtaining a self-healing material with a particle size of 50 - 200 μm.

[0067] Preparation of silicone-modified dendritic polyamide: Prepare an acetone solution of trimesoyl chloride, and drop bis-terminal amino silicone oil with a molecular weight of 400-600 into the solution. The molar ratio of trimesoyl chloride to terminal amino silicone oil is 1:2, and react at 40 °C for 7 hours, then filter and wash to obtain.

[0068] Preparation of self-healing coating for tower grounding metal: (1) Mix 50 parts by weight of phenolic epoxy resin (brand F-44), 8 parts by weight of red lead, 6 parts by weight of wollastonite, 20 parts by weight of self-healing material, 3 parts by weight of dispersant (BYK DISPERBYK-103) and 4 parts by weight of polyamide (brand 650) evenly, then add them into a grinding machine for grinding. After grinding, filter to obtain a uniform mixture; (2) Add 5 parts by weight of anilinized ladder-type polyhedral oligomeric silsesquioxane to the mixture and stir evenly to obtain a uniformly mixed first component; (3) Before coating, mix the first component with 20 parts by weight of curing agent (silicone-modified dendritic polyamide) of the second component to form a high-temperature and corrosion-resistant self-healing coating.

[0069] Spray the self-healing coating on the surface of the sandblasted metal member (flat steel) to form a coating with a thickness of 0.2 mm. After the coating is cured, conduct an EIS test according to the test standard ISO16773-2:2007. It can maintain good anti-corrosion performance after being soaked in 4.4 wt% NaCl solution for 50 days, and its Zf = 1.49×10 6 Ω·cm 2 , after the cured coating is heated at 670 °C for 1700 h, the metal surface is not damaged and the metal member is effectively protected.

[0070] Comparative Example 1 On the basis of Example 1, do not add anilinized ladder-type polyhedral oligomeric silsesquioxane to the coating, and change the dosage of the curing agent (silicone-modified dendritic polyamide) to 18 parts by weight, and keep the others the same as in Example 1.

[0071] Spray the self-healing coating on the surface of the sandblasted metal member (flat steel) to form a coating with a thickness of 0.2 mm. After the coating is cured, conduct an EIS test according to the test standard ISO16773-2:2007. Surface corrosion occurs after being soaked in 4.5 wt% NaCl solution for 20 days, and its Zf = 1.02×10 6 Ω·cm 2 , after the cured coating is heated at 650 °C for 500 h, the metal surface is damaged.

[0072] Comparative Example 2 On the basis of Example 1, the curing agent in the coating is a dendritic polyamide without silicone modification, and the others are the same as in Example 1.

[0073] Among them, the preparation method of the hyperbranched polyamide is as follows: Prepare an acetone solution of trimellitic acid trichloride, and dropwise add an aqueous solution of p-phenylenediamine to the solution. The molar ratio of trimellitic acid trichloride to p-phenylenediamine is 1:1, and react at 19 °C for 5 hours, then filter and wash to obtain.

[0074] The self-healing coating is sprayed on the surface of a sandblasted metal component (flat steel) to form a coating with a thickness of 0.2 mm. After the coating is cured, an EIS test is carried out according to the test standard ISO16773-2:2007. Surface corrosion occurs after soaking in a 4.5 wt% NaCl solution for 37 days, and its Zf = 1.19×10 6 Ωcm 2 , and after the cured coating is heated at 650 °C for 800 h, the metal surface is damaged.

[0075] The above is a specific description of the preferred embodiments of the present invention, but the present invention is not limited to the described embodiments. Those skilled in the art can make various equivalent deformations or substitutions without departing from the spirit of the present invention, and these equivalent deformations or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A self-healing coating for tower grounding metal, characterized in that, It includes a first component and a second component; Calculated by weight, the first component includes 20 - 90 parts of phenolic epoxy resin, 3 - 5 parts of aniline-modified ladder polysilsesquioxane, 5 - 8 parts of red lead, 6 - 9 parts of wollastonite, 20 - 40 parts of self-healing material, 1 - 3 parts of dispersant, and 3 - 6 parts of polyamide; Calculated by weight, the second component includes 15 - 20 parts of curing agent; The aniline-modified ladder polysilsesquioxane is formed by anilination of phenyl ladder polysilsesquioxane; The curing agent is an organosilicon-modified dendritic polyamide, and the preparation method of the organosilicon-modified dendritic polyamide is as follows: Prepare an acetone solution of trimellitic acid trichloride, dropwise add bis-terminal amino silicone oil to the solution, heat and react for 6 - 8 hours, and then carry out suction filtration and washing to obtain it.

2. The self-repairing coating for tower grounding metal according to claim 1, wherein, The mass ratio of the curing agent to the aniline-modified ladder polysilsesquioxane is (3 - 4):

1.

3. The self-repairing coating for tower grounding metal according to claim 1, characterized in that, The preparation method of the aniline-modified ladder polysilsesquioxane is as follows: Add phenyl ladder polysilsesquioxane to fuming nitric acid, stir at low temperature for 0.5 h, then stir at room temperature for 5 - 20 h, let it stand for precipitation and then dry. Dissolve the dried material in a tetrahydrofuran or dioxane solvent, then add palladium-carbon catalyst, add formic acid at 50 - 80 °C and react for 1 - 5 h, and obtain aniline-modified ladder polysilsesquioxane after filtration, washing and drying; The low temperature for the low-temperature stirring refers to -20 - 5 °C.

4. The self-healing coating for tower grounding metal according to claim 3, wherein, The molar ratio of the phenyl ladder polysilsesquioxane to the palladium-carbon catalyst is 1:(0.01 - 0.1).

5. The self-healing coating for tower grounding metal according to claim 3, characterized in that, The molar ratio of the phenyl ladder polysilsesquioxane to the formic acid is 1:(1 - 2).

6. The self-healing coating for tower grounding metal according to claim 1, characterized in that, The self-healing material is a composite microcapsule formed with tung oil and linseed oil as the core material and polyaniline as the shell material.

7. The self-healing coating for tower grounding metal according to claim 6, characterized in that, The particle size of the self-healing material is 50 - 200 μm.

8. A self-healing coating for tower grounding metal according to claim 1, characterized in that, The dispersant is an amphoteric dispersant.

9. A preparation method of a self-healing coating for tower grounding metal as described in any one of claims 1-8, characterized in that, The preparation method includes the following steps: (1) Mix the other raw materials of the first component except the aniline-modified ladder polysilsesquioxane evenly, grind them, and filter to obtain a uniform mixture; (2) Add the aniline-modified ladder polysilsesquioxane to the mixture in step (1) and mix evenly to obtain the first component; (3) Before applying the coating, mix the first component and the second component to obtain a self-healing coating with high temperature resistance and corrosion prevention.

10. Use of a self-healing coating for tower grounding metal as described in any one of claims 1-8, characterized in that, The application method is: apply the self-healing coating to the surface of a metal component to form a coating with high temperature resistance and corrosion prevention.

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