Super-hydrophobic nano-structure coating for electrical insulator and preparation method of super-hydrophobic nano-structure coating

Abstract

The invention relates to the technical field of electrical insulating materials, and discloses a super-hydrophobic nano-structure coating for an electrical insulator and a preparation method of the super-hydrophobic nano-structure coating. The static contact angle of the coating ranges from 117 degrees to 155 degrees, and the leakage current peak value is smaller than 60 mA. A material A for forming the coating contains modified nano silicon dioxide, polysiloxane and aluminum oxide trihydrate. The super-hydrophobic nano-structure coating provided by the invention has excellent super-hydrophobicity and electric leakage resistance, and can effectively reduce the risks of partial discharge, flashover and the like of an electric insulator in a polluted environment.

Description

Technical Field

[0001] This invention relates to the field of electrical insulation materials technology, specifically to a superhydrophobic nanostructure coating for electrical insulators and its preparation method. Background Technology

[0002] In power system operation, the surface condition of insulators directly affects their insulation performance and service life. Especially in polluted environments such as high humidity, sea salt spray, and industrial dust, insulator surfaces are prone to accumulating dirt and moisture, forming conductive paths that can lead to partial discharge, dry-charge arcing, flashover, and even breakdown, seriously threatening power grid safety. Traditional solutions, such as manual cleaning and thermal de-icing, are not only complex, costly, and inefficient, but also fail to provide lasting improvements in insulation performance.

[0003] Hydrophobic coatings, due to their high contact angle, low surface energy, and excellent self-cleaning and anti-fouling properties, show great promise in preventing flashover of electrical insulators. However, existing superhydrophobic coatings generally suffer from the following shortcomings: (1) The structure construction relies on high-cost processes such as photolithography and plasma etching; (2) The fluoropolymer materials used are costly and have poor environmental friendliness; (3) Nanoparticles are prone to agglomeration, which leads to uneven surface roughness of the coating and reduced hydrophobicity; (4) The leakage current control capability of some coatings is weak, which limits their practical application in high voltage insulators.

[0004] Therefore, developing a superhydrophobic nanostructure coating with widely available materials, uniform structure, strong anti-fouling properties, and excellent electrical performance is of great engineering significance for improving the stability and durability of power equipment. Summary of the Invention

[0005] The purpose of this invention is to provide a nanostructured coating with excellent superhydrophobicity and anti-leakage properties, and with a simple preparation process and controllable cost.

[0006] To achieve the above objectives, a first aspect of the present invention provides a superhydrophobic nanostructure coating for electrical insulators, the coating having a static contact angle of 117°-155° and a peak leakage current of <60mA.

[0007] A second aspect of the present invention provides a method for preparing the superhydrophobic nanostructure coating described in the first aspect, the method comprising: (1) In the presence of solvent II, the modified nano-silica and alumina trihydrate are brought into first contact to obtain a mixture; (2) The mixture is brought into a second contact with polysiloxane to obtain a coating dispersion system; (3) The coating dispersion system is sprayed onto the surface of an electrical insulator to obtain the superhydrophobic nanostructure coating.

[0008] Through the above technical solution, the present invention has at least the following advantages: (1) By controlling the type and amount of nano-silica, the static contact angle of the provided superhydrophobic nanostructure coating is controllable within the range of 117°-155°, which has excellent superhydrophobicity and self-cleaning ability, and can effectively reduce liquid wetting and contaminant adhesion.

[0009] (2) The leakage current peak of the superhydrophobic nanostructure coating provided by the present invention is less than 60mA, which meets the GB / T6553-2024 standard. It has good anti-leakage performance and can reduce the risk of partial discharge and flashover of electrical insulators in polluted environments.

[0010] (3) The superhydrophobic nanostructure coating preparation process provided by the present invention is simple, does not require high temperature treatment or plasma equipment, is suitable for large-scale industrial application, and is applicable to the surface protection of various electrical insulators such as glass, ceramics and composite materials, especially suitable for coastal, high humidity, dust and other pollution scenarios.

[0011] (4) The raw materials used in the superhydrophobic nanostructure coating provided by the present invention are common industrial materials, which do not require fluorine-containing reagents and are environmentally friendly. Detailed Implementation

[0012] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0013] As previously stated, a first aspect of the present invention provides a superhydrophobic nanostructure coating for electrical insulators, the coating having a static contact angle of 117°-155° and a peak leakage current of <60mA.

[0014] Preferably, the material A forming the coating contains modified nano-silica, polysiloxane, and alumina trihydrate.

[0015] More preferably, based on the total mass of material A, the content of modified nano-silica is 9-33 wt%, the content of polysiloxane is 40-55 wt%, and the content of alumina trihydrate is 27-36 wt%.

[0016] Preferably, the modified nano-silica is a product prepared by a method comprising the following steps: In the presence of solvent I, the raw material nano-silica is reacted with a modifier to obtain the modified nano-silica; the modifier is selected from at least one of octylsilane, dimethyldichlorosilane, and polydimethylsilane.

[0017] Preferably, the raw material nano-silica has a weight-average diameter of 20-50 nm and a specific surface area of ​​125-175 m². 2 / g.

[0018] Preferably, the mass ratio of the raw material nano-silica to the modifier is 8-12:1.

[0019] Preferably, the viscosity of solvent I at 25°C is 0.5-0.6 mPa. s.

[0020] Preferably, solvent I is selected from at least one of toluene, p-xylene, and cyclohexane.

[0021] More preferably, the mass ratio of the raw material nano-silica to the solvent I is 1:4-6.

[0022] In a preferred embodiment, the reaction conditions include: a temperature of 65-75°C, a time of 1.8-2.5 h, and a stirring speed of 380-420 rpm.

[0023] According to a preferred embodiment, the method further includes: firstly, ultrasonically dispersing the raw material nano-silica in solvent I for 15-25 min (frequency 45-55 kHz) to obtain a suspension; then adding the modifier to the suspension to carry out the reaction; after the reaction is completed, centrifuging at 2000-4000 rpm for 5-15 min; washing the obtained product with anhydrous ethanol 2-5 times; and vacuum drying at 50-70℃ for 3-5 h to obtain the modified nano-silica.

[0024] Preferably, the viscosity of the polysiloxane at 25°C is 50-200 cSt.

[0025] Preferably, the average particle size of the alumina trihydrate is 1-3 μm.

[0026] As previously described, a second aspect of the present invention provides a method for preparing the superhydrophobic nanostructure coating described in the first aspect, the method comprising: (1) In the presence of solvent II, the modified nano-silica and alumina trihydrate are brought into first contact to obtain a mixture; (2) The mixture is brought into a second contact with polysiloxane to obtain a coating dispersion system; (3) The coating dispersion system is sprayed onto the surface of an electrical insulator to obtain the superhydrophobic nanostructure coating.

[0027] Preferably, the viscosity of solvent II at 25°C is 1.3-2.4 mPa. s.

[0028] Preferably, solvent II is selected from at least one of isopropanol, propylene glycol methyl ether, and ethanol.

[0029] Preferably, step (1) further includes: first, ultrasonically dispersing the modified nano-silica in solvent II for 20-40 min to obtain a nano-silica dispersion; then adding alumina trihydrate to the nano-silica dispersion.

[0030] In a preferred embodiment, in step (1), the conditions for the first contact include: a temperature of 10-40°C and a time of 25-35 min.

[0031] In a preferred embodiment, in step (2), the conditions for the second contact include: a temperature of 10-40°C and a time of 25-35 min.

[0032] Preferably, before spraying, the surface of the electrical insulator is cleaned sequentially with acetone and isopropanol to remove surface impurities.

[0033] Preferably, in step (3), the spraying is performed using a spray gun.

[0034] More preferably, the spraying operation conditions include: the distance between the nozzle of the spray gun and the surface of the electrical insulator is 20-25cm, the spraying pressure is 25-35 PSI, the number of sprays is 2-3, the single spraying time is 10s, and the interval between two adjacent sprays at 25℃ is 10-20min.

[0035] In a preferred embodiment, the spraying operation further includes: after the final spraying is completed, curing the electrical insulator at 50-70°C for 1-3 hours.

[0036] The present invention will be described in detail below through examples. In the following examples, unless otherwise specified, all instruments and raw materials (analytical grade) used are commercially available products.

[0037] Raw material: nano-silica with a weight average diameter of 20 nm and a specific surface area of ​​140 m². 2 / g, with a purity of 99wt%, purchased from Hubei Huifu Nanomaterials Co., Ltd.; Modifier: Octylsilane, purchased from Aladdin Reagents (Shanghai) Co., Ltd.; Dimethyldichlorosilane, purchased from Wuhan Jiyesheng Chemical Co., Ltd.; Polydimethylsilane, purchased from Hoshine Silicon Industry Co., Ltd. Alumina trihydrate: with an average particle size of 3μm, purchased from Shandong Shibang Chemical Technology Co., Ltd. Polysiloxane: grade DC200, viscosity at 25°C is 100 cSt, purchased from Dow Corning.

[0038] Preparation Example 1 Modified nano-silica was prepared using the following steps: (1) Disperse 10g of raw material nano silica in 58mL of solvent I (specifically toluene) by ultrasonication for 20min (frequency 50kHz) to form a suspension; (2) Add 1g of modifier (specifically octylsilane) to the suspension obtained in step (1) and react at 70℃ and 400rpm for 2h; (3) Centrifuge at 3000 rpm for 10 min, wash the product three times with anhydrous ethanol, and vacuum dry at 60℃ for 4 h to obtain modified nano silica, named M-01.

[0039] Preparation Example 2 This preparation example uses the same process as Preparation Example 1. The difference is that this preparation example uses dimethyldichlorosilane as a modifier (the amount and mass are the same as in Preparation Example 1), and the modified nano-silica obtained is named M-02.

[0040] Preparation Example 3 This preparation example uses the same process as Preparation Example 1. The difference is that this preparation example uses polydimethylsilane as a modifier (the amount and mass are the same as in Preparation Example 1), and the modified nano-silica obtained is named M-03.

[0041] Example 1 (1) 9g of modified nano silica (specifically M-01) was ultrasonically dispersed in 100mL solvent II (specifically isopropanol) for 30min to obtain nano silica dispersion; (2) Add 36g of aluminum oxide trihydrate to the nano silica dispersion obtained in step (1), and perform the first contact at 25°C for 30min to obtain a mixture; (3) Add 55g of polysiloxane to the mixture obtained in step (2) and perform a second contact at 25°C for 30 minutes to obtain the coating dispersion system; (4) First, clean the surface of the electrical insulator with acetone and isopropanol in sequence to remove surface impurities; then, use a spray gun to spray the coating dispersion system obtained in step (3) onto the cleaned surface of the electrical insulator to obtain a superhydrophobic nanostructure coating; the distance between the nozzle of the spray gun and the surface of the electrical insulator is 25cm, the spraying pressure is 35 PSI, the number of sprays is 3, the single spraying time is 10s, and the interval between two adjacent sprays at 25℃ is 15min. After the last spraying is completed, the electrical insulator is cured in a 60℃ forced-air drying oven for 2h.

[0042] In this embodiment, in the material A (including modified nano silica, alumina trihydrate and polysiloxane) that forms the coating, the amount of modified nano silica is 9 wt%, the amount of alumina trihydrate is 36 wt%, and the amount of polysiloxane is 55 wt%.

[0043] Example 2 This embodiment uses the same process flow as Embodiment 1, except that in this embodiment: The amount of modified nano-silica used is 23g, the amount of alumina trihydrate used is 31g, and the amount of polysiloxane used is 46g. Specifically, in material A forming the coating, the amount of modified nano-silica is 23 wt%, the amount of alumina trihydrate is 31 wt%, and the amount of polysiloxane is 46 wt%.

[0044] Example 3 This embodiment uses the same process flow as Embodiment 1, except that in this embodiment: The amount of modified nano-silica used is 33g, the amount of alumina trihydrate used is 27g, and the amount of polysiloxane used is 40g. Specifically, in material A forming the coating, the amount of modified nano-silica is 33wt%, the amount of alumina trihydrate is 27wt%, and the amount of polysiloxane is 40wt%.

[0045] Example 4 This embodiment uses the same process as Example 1. The difference is that the modified nano-silica used in this embodiment is M-02 (the amount and mass are the same as in Example 1).

[0046] Example 5 This embodiment uses the same process as Example 1. The difference is that the modified nano-silica used in this embodiment is M-03 (the amount and mass are the same as in Example 1).

[0047] Comparative Example 1 Comparative Example 1 uses the same process flow as Example 1, except that in step (1): This comparative example uses the same mass of raw material nano-silica to replace the modified nano-silica in Example 1.

[0048] Test case The performance test data of the coating samples in the examples and comparative examples are shown in Table 1.

[0049] The static contact angle was measured in accordance with GB / T 24622-2022 "Guidelines for Measurement of Hydrophobicity of Insulator Surface".

[0050] The peak leakage current was determined in accordance with GB / T 6553-2024 "Test Method for Evaluation of Resistance to Tracking and Erosion of Electrical Insulation Materials Used in Harsh Environmental Conditions".

[0051] Table 1

[0052] The results above show that the superhydrophobic nanostructure coating provided by this invention has excellent superhydrophobicity and anti-leakage properties, and can effectively reduce the risks of partial discharge and flashover of electrical insulators in polluted environments.

[0053] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A superhydrophobic nanostructure coating for electrical insulators, characterized in that, The coating has a static contact angle of 117°-155° and a peak leakage current of <60mA.

2. The superhydrophobic nanostructure coating according to claim 1, characterized in that, Material A forming the coating contains modified nano-silica, polysiloxane, and aluminum oxide trihydrate; And / or, based on the total mass of material A, the content of the modified nano silica is 9-33 wt%, the content of the polysiloxane is 40-55 wt%, and the content of the alumina trihydrate is 27-36 wt%.

3. The superhydrophobic nanostructure coating according to claim 2, characterized in that, The modified nano-silica is a product prepared by a method comprising the following steps: In the presence of solvent I, the raw material nano-silica is reacted with a modifier to obtain the modified nano-silica; the modifier is selected from at least one of octylsilane, dimethyldichlorosilane, and polydimethylsilane. And / or, the raw material nano-silica has a weight-average diameter of 20-50 nm and a specific surface area of ​​125-175 m². 2 / g.

4. The superhydrophobic nanostructure coating according to claim 3, characterized in that, The mass ratio of the raw material nano-silica to the modifier is 8-12:

1.

5. The superhydrophobic nanostructure coating according to claim 3 or 4, characterized in that, The reaction conditions include: a temperature of 65-75℃, a time of 1.8-2.5h, and a stirring speed of 380-420rpm.

6. The superhydrophobic nanostructure coating according to claim 2, characterized in that, The viscosity of the polysiloxane at 25°C is 50-200 cSt.

7. The superhydrophobic nanostructure coating according to claim 2, characterized in that, The average particle size of the trihydrated alumina is 1-3 μm.

8. A method for preparing the superhydrophobic nanostructure coating according to any one of claims 1-7, characterized in that, The method includes: (1) In the presence of solvent II, the modified nano-silica and alumina trihydrate are brought into first contact to obtain a mixture; (2) The mixture is brought into a second contact with polysiloxane to obtain a coating dispersion system; (3) The coating dispersion system is sprayed onto the surface of an electrical insulator to obtain the superhydrophobic nanostructure coating.

9. The method according to claim 8, characterized in that, In step (1), the conditions for the first contact include: a temperature of 10-40°C and a time of 25-35 min; And / or, in step (2), the conditions for the second contact include: a temperature of 10-40°C and a time of 25-35 min.

10. The method according to claim 8 or 9, characterized in that, In step (3), the spraying is performed using a spray gun; And / or, the spraying operation conditions include: the distance between the nozzle of the spray gun and the surface of the electrical insulator is 20-25cm, the spraying pressure is 25-35 PSI, the number of sprays is 2-3, the single spraying time is 10s, and the interval between two adjacent sprays at 25℃ is 10-20min.

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