Self-repairing coating for tower grounding metal and its preparation method and application

Abstract

The present invention belongs to the field of coating technology, and specifically discloses a self-repairing coating for tower grounding metal, its preparation method, and application. The high-temperature resistant and corrosion-resistant self-repairing coating comprises a first component and a second component; the first component comprises, by weight, 20 to 90 parts of phenolic epoxy resin, 3 to 5 parts of aniline ladder 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 dispersant, and 3 to 6 parts of polyamide; the second component comprises, by weight, 15 to 20 parts of curing agent; wherein the aniline ladder polysilsesquioxane is formed by anilinization of phenyl ladder polysilsesquioxane. The present invention is suitable for corrosion protection of metal components exposed to 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 in particular relates to a self-repairing coating for tower grounding metal, and a preparation method and application thereof. Background Art

[0002] The corrosion of tower grounding materials is a major, long-standing concern for power systems. Grounding materials, buried in the soil for extended periods, are susceptible to corrosion, impacting their electrical conductivity and lifespan. Common grounding materials include flat steel, round steel, galvanized steel, copper, and copper-clad steel, but these materials generally lack corrosion resistance. Corrosion of grounding metal materials can cause a layer of high-resistivity corrosion products to form on their surface, which can affect the normal current dissipation of the grounding electrode, increase grounding resistance, and reduce grounding performance. The presence of the corrosion product layer alters the grounding electrode's current dissipation distribution, grounding resistance, surface potential, and step voltage distribution, thereby impacting the reliability of transmission lines and the safe operation of power systems. Conventional metal coating corrosion prevention involves applying a coating to the metal surface to prevent direct contact between the metal and the corrosive medium. This simply acts as a physical barrier, but cannot proactively prevent corrosion based on specific corrosion conditions, effectively mitigating metal corrosion.

[0003] Generally, corrosion inhibitors are added to paints, but they gradually dissipate after application, reducing their effectiveness. They can even interact with the base paint, weakening the inhibitor's effectiveness. Metal materials can still be affected by the surrounding medium and corrode. Long-term use can lead to damage or cracking, exposing the metal to corrosive environments.

[0004] Ladder polysilsesquioxanes were first synthesized from phenyltrichlorosilane via a simple hydrolysis and thermal equilibrium polycondensation method. They are considered to spontaneously form polymers with a regular double-chain structure. Among ladder polysilsesquioxanes with various substituents, those containing phenyl groups exhibit a semi-rigid structure. This combination of rigidity and flexibility ensures both excellent flexibility and tensile strength while maintaining good solubility. Their incorporation into coating materials can enhance coating performance by leveraging the aging resistance of polysiloxanes and the high-temperature resistance of phenylsiloxanes. However, the poor compatibility of ladder polysilsesquioxanes with resin matrices remains a challenge. Summary of the Invention

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

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] In a first aspect, the present invention provides a self-repairing coating for tower grounding metal, comprising a first component and a second component;

[0008] Calculated by weight, the first component includes 20 to 90 parts of phenolic epoxy resin, 3 to 5 parts of aniline trapezoidal polysilsesquioxane, 5 to 8 parts of red lead, 6 to 9 parts of wollastonite, 20 to 40 parts of self-healing material, 1 to 3 parts of dispersant and 3 to 6 parts of polyamide;

[0009] The second component includes 15 to 20 parts by weight of a curing agent;

[0010] The anilide ladder-shaped polysilsesquioxane is formed by anilation of phenyl ladder-shaped polysilsesquioxane;

[0011] The curing agent is an organosilicon-modified dendritic polyamide, and the preparation method of the organosilicon-modified dendritic polyamide is as follows:

[0012] Prepare an acetone solution of trimesoyl chloride, add double-terminated amino silicone oil dropwise to the solution, heat and react for 6 to 8 hours, filter and wash to obtain the product.

[0013] Preferably, the molecular weight of the double-terminated amino silicone oil is 400-600.

[0014] Preferably, the molar ratio of trimesoyl chloride to amino-terminated silicone oil is 1:1-2.

[0015] Preferably, the temperature of the heating reaction is 30-40°C.

[0016] Phenolic epoxy resin has the advantages of high stability and heat resistance, acid resistance, alkali resistance, and wear resistance. Phenolic epoxy resin is combined with a curing agent to give the coating the advantages of traditional solvent-based phenolic epoxy coatings. It also has good flexibility, impact resistance, low VOC emissions, and better workability.

[0017] Preferably, the mass ratio of the curing agent to the aniline ladder-shaped polysilsesquioxane is (3-5):1, and more preferably, the mass ratio of the curing agent to the aniline ladder-shaped polysilsesquioxane is (3-4):1.

[0018] The total amount of curing agent and aniline ladder polysilsesquioxane should be limited to a certain range to avoid excessive curing material affecting coating performance. If the amount of aniline ladder polysilsesquioxane is too small, the effect will be insignificant; if the amount of aniline ladder polysilsesquioxane is too large, the coating will become brittle and its impact resistance will deteriorate.

[0019] More preferably, the mass ratio of the anilide ladder-shaped polysilsesquioxane to the curing agent of the second component is 4:1.

[0020] Preferably, the preparation method of the anilide ladder-shaped polysilsesquioxane is as follows:

[0021] Phenyl ladder polysilsesquioxane is added to fuming nitric acid, stirred at low temperature for 0.5 h, then stirred at room temperature for 5 to 20 h, allowed to stand and precipitate, and then dried. The dried material is dissolved in tetrahydrofuran or dioxane solvent, and then palladium carbon catalyst is added. Formic acid is added at 50 to 80°C and reacted for 1 to 5 h. After filtering, washing, and drying, an anidized ladder polysilsesquioxane is obtained.

[0022] Preferably, the low temperature for the low temperature stirring is -20 to 5°C.

[0023] The reaction process for preparing an anidized ladder-shaped polysilsesquioxane is as follows:

[0024] .

[0025] The phenyl ladder polysilsesquioxane was purchased from Forsman Technology (Beijing) Co., Ltd.

[0026] Preferably, the molar ratio of the phenyl ladder polysilsesquioxane to the palladium-carbon catalyst is 1:(0.01-0.1).

[0027] Preferably, the molar ratio of the phenyl ladder polysilsesquioxane to the formic acid is 1:(1-2).

[0028] The present invention prepares anilide ladder polysilsesquioxane by nitration and hydrogenation reduction of phenyl ladder polysilsesquioxane. The aniline group can react with the epoxy resin used in the coating, so that the anilide ladder polysilsesquioxane can be uniformly dispersed in the resin system, thereby fully utilizing the characteristics of the anilide ladder polysilsesquioxane.

[0029] Adding aniline-modified ladder-shaped polysilsesquioxane to coatings improves their high-temperature, aging, and corrosion resistance. The Si-O-Si chemical bond within the aniline-modified ladder-shaped polysilsesquioxane enhances the coating's high-temperature resistance and has a certain hysteresis effect on combustion. Furthermore, the Si-O-Si chemical bond is resistant to aging and can effectively reduce the aging rate of phenolic epoxy resin in natural environments, thereby effectively maintaining its corrosion resistance. The inherent rigidity and flexibility of the ladder-shaped polysilsesquioxane enhance the coating's hardness and impact resistance after curing.

[0030] Anilide ladder polysilsesquioxane has an amino group, that is, anilide ladder polysilsesquioxane plays a role similar to a curing agent. Therefore, the content of anilide ladder polysilsesquioxane in the coating should not be too high, otherwise it will cause the phenolic epoxy resin of the first component to cure prematurely.

[0031] Red lead and wollastonite act like toners and have strong covering power. In addition, red lead and wollastonite also have high antioxidant properties, high stability and corrosion resistance.

[0032] Preferably, the self-repairing material is a composite microcapsule formed by using tung oil and linseed oil as core materials and polyaniline as shell material.

[0033] More preferably, the preparation method of the self-repairing material is as follows:

[0034] The core material and emulsifier were rapidly stirred at 50°C for 20 minutes, and then deionized water was added and emulsified for 15 to 30 minutes to form a stable oil-in-water emulsion. Aniline was then added to the aqueous phase. 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 to obtain a self-healing material.

[0035] Preferably, the stirring speed after the core material and the emulsifier are mixed is 300 to 1200 r / min.

[0036] Preferably, the emulsifier includes sodium lignin sulfonate, and the mass of the emulsifier accounts for 1 to 7% of the mass of the core material.

[0037] Preferably, the mass ratio of the core material to the shell material is 1:1.

[0038] Preferably, the particle size of the self-repairing material is 50 to 200 μm.

[0039] The principle of self-healing materials is: the paint solidifies into a coating. When cracks occur in the coating, causing the composite microcapsules to rupture, the tung oil and linseed oil in it are released and fill the cracks. After coming into contact with air, they react with oxygen and solidify, achieving self-repair of the coating cracks.

[0040] Preferably, the dispersant is an amphoteric dispersant, such as a phosphate-type high molecular polymer.

[0041] In a second aspect, the present invention provides a method for preparing a self-repairing coating for tower grounding metal, the preparation method comprising the following steps:

[0042] (1) mixing the other raw materials of the first component except the anilide ladder-shaped polysilsesquioxane uniformly, grinding, and filtering to obtain a uniform mixture;

[0043] (2) adding anilide ladder polysilsesquioxane to the mixture of step (1) and mixing uniformly to obtain a first component;

[0044] (3) Before applying the coating, the first component is mixed with the second component to obtain a high temperature resistant and corrosion resistant self-repairing coating.

[0045] In a third aspect, the present invention provides an application of a self-repairing coating for tower grounding metal, wherein the application method is: applying the self-repairing coating to the surface of a metal component to form a high-temperature resistant and corrosion-resistant coating.

[0046] The beneficial effects of this application are as follows:

[0047] The present invention combines the characteristics of anti-corrosion coating technology, self-repairing technology and anilide trapezoidal polysilsesquioxane technology, comprehensively improving the corrosion resistance, high temperature resistance and aging resistance of the coating. The preparation method of the present invention is simple, low-cost and easy to mass-produce.

[0048] The present invention uses aniline ladder polysilsesquioxane to improve the high-temperature resistance, aging resistance, and corrosion resistance of the coating. The Si-O-Si chemical bonds in the aniline ladder polysilsesquioxane are relatively resistant to high temperatures. Introducing the Si-O-Si chemical bonds into the coating can improve the high-temperature resistance of the coating and have a certain hysteresis effect on combustion. The rigid and flexible structural characteristics of the aniline ladder polysilsesquioxane can also improve the hardness and impact resistance of the coating. The aging resistance of the aniline ladder polysilsesquioxane can effectively reduce the aging rate of epoxy resin in the natural environment, thereby effectively maintaining the corrosion resistance.

[0049] The curing agent of the present invention is an organosilicon-modified dendritic polyamide. Organosilicon segments and Si-O-Si chemical bonds are introduced into the dendritic polyamide structure. At the same time, phenyl groups are contained, so that the dendritic polyamide not only combines well with the phenolic epoxy resin, but also has good binding force with the aniline ladder polysilsesquioxane, and is well dispersed with each other. Therefore, the organosilicon-modified dendritic polyamide and the aniline ladder polysilsesquioxane can synergistically improve the high temperature resistance and corrosion resistance of the coating.

[0050] The present invention adopts self-repairing materials. When cracks occur in the coating and the composite microcapsules rupture, the tung oil and linseed oil in the materials are released and fill the cracks. After contact with air, they react with oxygen and solidify, thereby achieving self-repair of the coating cracks. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 Schematic diagram of the molecular structure and H-NMR spectrum data of the aniline ladder-shaped polysilsesquioxane prepared in Example 1. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0053] Example 1

[0054] Preparation of aniline 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 for 1 h. After filtration, washing and drying, aniline ladder polysilsesquioxane was obtained. Its molecular structure diagram and H NMR spectrum data are shown in FIG. Figure 1 shown.

[0055] Preparation of self-healing material: The core material (tung oil and linseed oil in a volume ratio of 1:1) and the emulsifier sodium lignin sulfonate were stirred at 500 r / min for 20 minutes at 50°C. The mass of sodium lignin sulfonate was 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 with a mass ratio of core material to aniline of 1:1. Due to the electrostatic interaction between the emulsifier and aniline, it was adsorbed on the oil-water interface. The aniline was chemically oxidized and polymerized to form a PANI shell, obtaining a self-healing material with a particle size of 50 to 200 μm.

[0056] Preparation of organosilicon-modified dendritic polyamide: prepare an acetone solution of trimesoyl chloride, add double-terminated amino silicone oil with a molecular weight of 400-600 dropwise to the solution, the molar ratio of trimesoyl chloride to amino-terminated silicone oil being 1:1, react at 30°C for 7 hours, filter and wash to obtain the product.

[0057] Preparation of self-repairing coating for tower grounding metal:

[0058] (1) 20 parts by weight of phenolic epoxy resin (brand 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 (DISPERBYK-103) and 3 parts by weight of polyamide (brand 650) were mixed uniformly, added to a grinder for grinding, and filtered to obtain a uniform mixture after grinding.

[0059] (2) adding 3 parts by weight of anilide trapezoidal polysilsesquioxane to the mixture and stirring uniformly to obtain a uniformly mixed first component;

[0060] (3) Before coating, the first component is mixed with 15 parts by weight of the curing agent (organic silicone modified dendritic polyamide) of the second component to form a high temperature and corrosion resistant self-healing coating.

[0061] The self-repairing coating was sprayed onto 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 performed according to the test standard ISO16773-2:2007. The coating maintained good anti-corrosion performance after immersion in a 4.5 wt% NaCl solution for 50 days, with a Zf = 1.53 × 10 6 Ωcm 2 The cured coating was heated at 650℃ for 2000 h without any damage to the metal surface, and the metal components were effectively protected.

[0062] Example 2

[0063] Preparation of aniline 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 for 5 h. After reaction, filtration, washing and drying were obtained to obtain aniline ladder polysilsesquioxane.

[0064] Preparation of self-healing materials: The core material (tung oil and linseed oil in a volume ratio of 1:1) and the emulsifier sodium lignin sulfonate were stirred at 1000 r / min at 50°C for 20 minutes. The mass of sodium lignin sulfonate 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 with a mass ratio of core material to aniline of 1:1. Due to the electrostatic interaction between the emulsifier and aniline, it was adsorbed on the oil-water interface. The aniline was chemically oxidized and polymerized to form a PANI shell, obtaining a self-healing material with a particle size of 50 to 200 μm.

[0065] Preparation of organosilicon-modified dendritic polyamide: prepare an acetone solution of trimesoyl chloride, add double-terminated amino silicone oil with a molecular weight of 400-600 dropwise to the solution, the molar ratio of trimesoyl chloride to amino-terminated silicone oil being 1:2, react at 40°C for 8 hours, filter and wash to obtain the product.

[0066] Preparation of self-repairing coating for tower grounding metal:

[0067] (1) 90 parts by weight of phenolic epoxy resin (brand 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 (DISPERBYK-103) and 6 parts by weight of polyamide (brand 650) were mixed uniformly, added to a grinder for grinding, and filtered to obtain a uniform mixture after grinding.

[0068] (2) adding 5 parts by weight of anilide trapezoidal polysilsesquioxane to the mixture and stirring uniformly to obtain a uniformly mixed first component;

[0069] (3) Before coating, the first component is mixed with 20 parts by weight of the curing agent (organic silicon modified dendritic polyamide) of the second component to form a high temperature resistant and corrosion resistant self-healing coating.

[0070] The self-repairing coating was sprayed on the surface of the sandblasted metal component (flat steel) to form a coating with a thickness of 0.2mm. After the coating was cured, EIS test was carried out according to the test standard ISO16773-2:2007. It can maintain good anti-corrosion performance after being immersed in 4.4wt% NaCl solution for 50 days. f =1.49×10 6 Ωcm 2 The cured coating was heated at 660℃ for 1600 h without any damage to the metal surface, and the metal components were effectively protected.

[0071] Example 3

[0072] Preparation of aniline 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 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 for 2 h. After filtration, washing and drying, aniline ladder polysilsesquioxane was obtained.

[0073] Preparation of self-healing materials: The core material (tung oil and linseed oil in a volume ratio of 1:1) and the emulsifier sodium lignin sulfonate were stirred at 1000 r / min at 50°C for 20 minutes. The mass of sodium lignin sulfonate 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 with a mass ratio of core material to aniline of 1:1. Due to the electrostatic interaction between the emulsifier and aniline, it was adsorbed on the oil-water interface. The aniline was chemically oxidized and polymerized to form a PANI shell, obtaining a self-healing material with a particle size of 50 to 200 μm.

[0074] Preparation of organosilicon-modified dendritic polyamide: prepare an acetone solution of trimesoyl chloride, add double-terminated amino silicone oil with a molecular weight of 400-600 dropwise to the solution, the molar ratio of trimesoyl chloride to amino-terminated silicone oil being 1:1.5, react at 35°C for 6 hours, filter and wash to obtain the product.

[0075] Preparation of self-repairing coating for tower grounding metal:

[0076] (1) 50 parts by weight of phenolic epoxy resin (brand 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 (DISPERBYK-103) and 4 parts by weight of polyamide (brand 650) were mixed uniformly, added to a grinder for grinding, and filtered to obtain a uniform mixture after grinding.

[0077] (2) adding 4 parts by weight of anilide trapezoidal polysilsesquioxane to the mixture and stirring uniformly to obtain a uniformly mixed first component;

[0078] (2) Before coating, the first component is mixed with 18 parts by weight of the curing agent (organosilicon-modified dendritic polyamide) of the second component to form a high-temperature and corrosion-resistant self-healing coating.

[0079] The self-repairing coating was sprayed onto 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 performed according to the test standard ISO16773-2:2007. The coating maintained good anti-corrosion performance after immersion in a 4.3 wt% NaCl solution for 50 days, with a Zf of 1.45 × 10 6 Ωcm 2 The cured coating was heated at 650℃ for 1500 h without any damage to the metal surface, and the metal components were effectively protected.

[0080] Example 4

[0081] Preparation of aniline 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 -15°C for 0.5 h, then stirred at room temperature for 8 h. After precipitation and drying, it was dissolved in dry tetrahydrofuran solvent, 0.04 mol of palladium carbon catalyst was added, and 1.2 mol of formic acid was added at 70°C for 2 h. After filtration, washing and drying, aniline ladder polysilsesquioxane was obtained.

[0082] Preparation of self-healing material: The core material (tung oil and linseed oil in a volume ratio of 1:1) and the emulsifier sodium lignin sulfonate were stirred at 800 r / min at 50°C for 20 minutes. The mass of sodium lignin sulfonate was 7% of the mass of the core material. Then deionized water was added and emulsified for 30 minutes to form a stable oil-in-water emulsion. Subsequently, aniline was added to the aqueous phase with a mass ratio of core material to aniline of 1:1. Due to the electrostatic interaction between the emulsifier and aniline, it was adsorbed on the oil-water interface. The aniline was chemically oxidized and polymerized to form a PANI shell, obtaining a self-healing material with a particle size of 50 to 200 μm.

[0083] Preparation of organosilicon-modified dendritic polyamide: prepare an acetone solution of trimesoyl chloride, add double-terminated amino silicone oil with a molecular weight of 400-600 dropwise to the solution, the molar ratio of trimesoyl chloride to amino-terminated silicone oil being 1:1.2, react at 33°C for 7 hours, filter and wash to obtain the product.

[0084] Preparation of self-repairing coating for tower grounding metal:

[0085] (1) 40 parts by weight of phenolic epoxy resin (brand 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 (DISPERBYK-103) and 6 parts of polyamide (brand 650) were mixed uniformly, added to a grinder for grinding, and filtered to obtain a uniform mixture after grinding.

[0086] (2) adding 5 parts by weight of anilide trapezoidal polysilsesquioxane to the mixture and stirring uniformly to obtain a uniformly mixed first component;

[0087] (3) Before coating, the first component is mixed with 16 parts by weight of the curing agent (organosilicon-modified dendritic polyamide) of the second component to form a high-temperature and corrosion-resistant self-healing coating.

[0088] The self-repairing coating was sprayed onto 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 performed according to the test standard ISO16773-2:2007. The coating maintained good anti-corrosion performance after immersion in a 4.2 wt% NaCl solution for 50 days, with a Zf of 1.48 × 10 6 Ωcm 2 The cured coating was heated at 680℃ for 1660 h without any damage to the metal surface, and the metal components were effectively protected.

[0089] Example 5

[0090] Preparation of aniline 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 0°C for 0.5 h, then stirred at room temperature for 9 h. After precipitation and drying, it was dissolved in dry tetrahydrofuran solvent, 0.04 mol of palladium carbon catalyst was added, and 1.1 mol of formic acid was added at 70°C for 2 h. After filtration, washing and drying, aniline ladder polysilsesquioxane was obtained.

[0091] Preparation of self-healing material: The core material (tung oil and linseed oil in a volume ratio of 1:1) and the emulsifier sodium lignin sulfonate were stirred at 1200 r / min at 50°C for 20 minutes. The mass of sodium lignin sulfonate was 1% of the mass of the core material. Then deionized water was added and emulsified for 20 minutes to form a stable oil-in-water emulsion. Subsequently, aniline was added to the aqueous phase with a mass ratio of core material to aniline of 1:1. Due to the electrostatic interaction between the emulsifier and aniline, it was adsorbed on the oil-water interface. The aniline was chemically oxidized and polymerized to form a PANI shell, obtaining a self-healing material with a particle size of 50 to 200 μm.

[0092] Preparation of organosilicon-modified dendritic polyamide: prepare an acetone solution of trimesoyl chloride, add double-terminated amino silicone oil with a molecular weight of 400-600 dropwise to the solution, the molar ratio of trimesoyl chloride to amino-terminated silicone oil being 1:2, react at 40°C for 7 hours, filter and wash to obtain the product.

[0093] Preparation of self-repairing coating for tower grounding metal:

[0094] (1) 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 (DISPERBYK-103) and 4 parts by weight of polyamide (brand 650) were mixed uniformly, added to a grinder for grinding, and filtered to obtain a uniform mixture after grinding.

[0095] (2) adding 5 parts by weight of anilide trapezoidal polysilsesquioxane to the mixture and stirring uniformly to obtain a uniformly mixed first component;

[0096] (3) Before coating, the first component is mixed with 20 parts by weight of the curing agent (organic silicon modified dendritic polyamide) of the second component to form a high temperature resistant and corrosion resistant self-healing coating.

[0097] The self-repairing coating was sprayed onto 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 performed according to the test standard ISO16773-2:2007. The coating maintained good anti-corrosion performance after immersion in a 4.4 wt% NaCl solution for 50 days, with a Zf of 1.49 × 10 6 Ωcm 2 The cured coating was heated at 670℃ for 1700 h without any damage to the metal surface, and the metal components were effectively protected.

[0098] Comparative Example 1

[0099] On the basis of Example 1, no anilide ladder-shaped polysilsesquioxane was added to the coating, the amount of the curing agent (organosilicon-modified dendritic polyamide) was changed to 18 parts by weight, and the other parameters remained the same as in Example 1.

[0100] The self-repairing coating was sprayed onto the surface of a sandblasted metal component (flat steel) to form a 0.2 mm thick coating. After the coating was cured, EIS testing was performed according to the test standard ISO16773-2:2007. After immersion in a 4.5 wt% NaCl solution for 20 days, surface corrosion occurred, with Zf = 1.02 × 10 6 Ωcm 2 After the cured coating was heated at 650℃ for 500 h, the metal surface was damaged.

[0101] Comparative Example 2

[0102] On the basis of Example 1, the curing agent in the coating is a dendritic polyamide that has not been modified with silicone, and the rest is consistent with Example 1.

[0103] Wherein, the preparation method of hyperbranched polyamide is as follows:

[0104] Prepare an acetone solution of trimesoyl chloride, add dropwise an aqueous solution of p-phenylenediamine to the solution, wherein the molar ratio of trimesoyl chloride to p-phenylenediamine is 1:1, react at 19° C. for 5 hours, filter and wash to obtain the product.

[0105] The self-repairing coating was sprayed onto the surface of a sandblasted metal component (flat steel) to form a 0.2 mm thick coating. After the coating was cured, EIS testing was performed according to the test standard ISO16773-2:2007. After immersion in a 4.5 wt% NaCl solution for 37 days, surface corrosion occurred, with Zf = 1.19 × 10 6 Ωcm 2 After the cured coating was heated at 650℃ for 800 h, the metal surface was damaged.

[0106] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A self-repairing coating for tower grounding metal, characterized in that: comprising a first component and a second component; Calculated by weight, the first component includes 20 to 90 parts of phenolic epoxy resin, 3 to 5 parts of aniline trapezoidal polysilsesquioxane, 5 to 8 parts of red lead, 6 to 9 parts of wollastonite, 20 to 40 parts of self-healing material, 1 to 3 parts of dispersant and 3 to 6 parts of polyamide; The second component includes 15 to 20 parts by weight of a curing agent; The mass ratio of the curing agent to the anilide ladder-shaped polysilsesquioxane is (3-4):1; The self-repairing material is a composite microcapsule formed by using tung oil and linseed oil as core materials and polyaniline as shell material; The anilide ladder-shaped polysilsesquioxane is formed by anilation of phenyl ladder-shaped 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 trimesoyl chloride, add double-terminated amino silicone oil dropwise to the solution, heat to 30-40°C, react for 6-8 hours, filter and wash to obtain the product.

2. The self-repairing coating for tower grounding metal according to claim 1, characterized in that: The preparation method of the anilide ladder-shaped polysilsesquioxane is as follows: Phenyl ladder polysilsesquioxane is added to fuming nitric acid, stirred at low temperature for 0.5 h, then stirred at room temperature for 5-20 h, allowed to settle and then dried, the dried material is dissolved in tetrahydrofuran or dioxane solvent, palladium carbon catalyst is added, formic acid is added at 50-80°C and reacted for 1-5 h, filtered, washed, and dried to obtain an anidized ladder polysilsesquioxane; The low temperature of the low temperature stirring refers to -20 to 5°C.

3. The self-repairing coating for tower grounding metal according to claim 2, characterized in that: The molar ratio of the phenyl ladder polysilsesquioxane to the palladium carbon catalyst is 1:(0.01-0.1).

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

5. The self-repairing coating for tower grounding metal according to claim 1, characterized in that: The particle size of the self-repairing material is 50 to 200 μm.

6. The self-repairing coating for tower grounding metal according to claim 1, characterized in that: The dispersant is an amphoteric dispersant.

7. A method for preparing a self-repairing coating for tower grounding metal according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: (1) mixing the other raw materials of the first component except the anilide ladder-shaped polysilsesquioxane uniformly, grinding, and filtering to obtain a uniform mixture; (2) adding anilide ladder polysilsesquioxane to the mixture of step (1) and mixing uniformly to obtain a first component; (3) Before applying the coating, the first component is mixed with the second component to obtain a high temperature resistant and corrosion resistant self-repairing coating.

8. An application of the self-repairing coating for tower grounding metal according to any one of claims 1 to 6, characterized in that: The application method is: applying the self-repairing coating to the surface of a metal component to form a high-temperature resistant and corrosion-resistant coating.

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