A high-strength insulating coating and its preparation method

Abstract

This application relates to the field of functional coatings technology, specifically disclosing a high-strength insulating coating and its preparation method. The high-strength insulating coating of this application comprises the following components in parts by weight: 30-40 parts of polydimethylsiloxane with a viscosity of 18000-22000 cp, 4-10 parts of silane coupling agent, 0.5-3 parts of composite nanofiller, 15-20 parts of aluminum hydroxide, 10-15 parts of silica, 0.2-0.5 parts of dibutyltin dilaurate, and 40-45 parts of diluent; the composite nanofiller is tungsten oxide, chitosan-modified montmorillonite, and black phosphorus in a weight ratio of 1:(0.1-0.8):(1.5-4). The high-strength insulating coating of this application maintains excellent mechanical strength and film adhesion even under extreme environments such as high temperature and high humidity, effectively solving the problem of performance degradation of existing coatings in complex environments, and is suitable for long-term insulation protection of electrical equipment, wires and cables, and other applications.

Description

Technical Field

[0001] This application relates to the field of functional coatings technology, specifically to a high-strength insulating coating and its preparation method. Background Technology

[0002] Insulation protection of electrical equipment and wires and cables is a key link in ensuring the safe and stable operation of the power system. As a core protective material, insulating coatings must have both excellent mechanical strength and insulation properties to resist physical wear and environmental erosion under complex working conditions.

[0003] Currently, most mainstream insulating coatings on the market are traditional polymer materials such as polyurethane and epoxy resin. For example, a related technology discloses a technique for preparing coatings by compounding silicone resin and epoxy resin with fillers such as silicon nitride and magnesium oxide. This technique improves the adhesion and corrosion resistance of the coating to a certain extent and can meet the basic protection requirements under normal conditions. However, it still has certain limitations. For example, in extreme environments such as high temperature and high humidity, the weather resistance and anti-aging performance of traditional material systems are insufficient, resulting in a significant decrease in the mechanical strength of the coating. The coating is prone to cracking and peeling, which directly threatens the operational safety of electrical equipment and shortens its service life. In addition, some technologies have attempted to further improve its mechanical strength by introducing modified materials such as silane coupling agents, but the performance improvement is generally limited.

[0004] Therefore, developing an insulating coating that can maintain excellent mechanical strength and insulation performance in complex environments is of great significance for the insulation protection of electrical equipment, wires and cables, and other materials. Summary of the Invention

[0005] In order to overcome the problems of poor weather resistance and aging resistance of existing insulating coatings, which easily lead to coating cracking after long-term use in complex environments, this application provides a high-strength insulating coating and its preparation method.

[0006] In a first aspect, this application provides a high-strength insulating coating, which adopts the following technical solution: A high-strength insulating coating comprises the following components in parts by weight: 30-40 parts of polydimethylsiloxane with a viscosity of 18000-22000cp, 4-10 parts of silane coupling agent, 0.5-3 parts of composite nanofiller, 15-20 parts of aluminum hydroxide, 10-15 parts of silica, 0.2-0.5 parts of dibutyltin dilaurate, and 40-45 parts of diluent; The composite nanofiller is tungsten oxide, chitosan-modified montmorillonite, and black phosphorus in a weight ratio of 1:(0.1-0.8):(1.5-4).

[0007] This application provides a high-strength insulating coating. Firstly, it uses polydimethylsiloxane with a viscosity of 18000-22000 cp as the matrix, ensuring good film-forming properties and coating uniformity while providing a stable mechanical support framework. Then, by introducing tungsten oxide, chitosan-modified montmorillonite, and black phosphorus as composite nanofillers in a weight ratio of 1:(0.1-0.8):(1.5-4), these three components synergistically construct a three-dimensional reinforcing network, significantly improving the coating's tensile strength, abrasion resistance, and impact resistance. Simultaneously, the insulating properties of black phosphorus and tungsten oxide further optimize the coating's insulation performance, resulting in a substantial increase in breakdown voltage. In summary, the high-strength insulating coating provided by this application maintains excellent mechanical strength and film adhesion under extreme environments such as high temperature and high humidity, effectively solving the problem of performance degradation of existing coatings in complex environments. It is suitable for long-term insulation protection of electrical equipment, wires, and cables.

[0008] The high-strength insulating coating comprises the following components in parts by weight: 35 parts of polydimethylsiloxane with a viscosity of 20000cp, 7.1 parts of silane coupling agent, 2 parts of composite nanofiller, 17.5 parts of aluminum hydroxide, 12.5 parts of silicon dioxide, 0.35 parts of dibutyltin dilaurate, and 42.5 parts of diluent.

[0009] In this application, the diluent may be xylene.

[0010] In some embodiments, the composite nanofiller may be present in parts by weight of 0.5-1 parts, 0.5-2 parts, 0.5-3 parts, 1-2 parts, 1-3 parts, or 2-3 parts.

[0011] In one specific implementation, the composite nanofiller may be 0.5 parts, 1 part, 2 parts or 3 parts by weight.

[0012] Optionally, the weight ratio of tungsten oxide, chitosan-modified montmorillonite, and black phosphorus is 1:(0.3-0.6):(2-3).

[0013] In some embodiments, the weight ratio of tungsten oxide, chitosan-modified montmorillonite, and black phosphorus can be 1:(0.1-0.3):2.5, 1:(0.1-0.45):2.5, 1:(0.1-0.6):2.5, 1:(0.1-0.8):2.5, 1:(0.31-0.45):2.5, 1:(0.3-0.6):2.5, 1:(0.3-0.8):2.5, 1:(0.45-0.6 ... 5-0.8): 2.5, 1: (0.6-0.8): 2.5, 1: 0.45: (1.5-2), 1: 0.45: (1.5-2.5), 1: 0.45: (1.5-3), 1: 0.45: (1.5-4), 1: 0.45: (2-2.5), 1: 0.45: (2-3), 1: 0.45: (2-4), 1: 0.45: (2.5-3), 1: 0.45: (2.5-4) or 1: 0.45: (3-4).

[0014] In one specific implementation, the weight ratio of tungsten oxide, chitosan-modified montmorillonite, and black phosphorus can also be 1:0.1:2.5, 1:0.3:2.5, 1:0.45:2.5, 1:0.6:2.5, 1:0.8:2.5, 1:0.45:1.5, 1:0.45:2, 1:0.45:3, or 1:0.45:4.

[0015] Optionally, the weight ratio of tungsten oxide, chitosan-modified montmorillonite, and black phosphorus is 1:0.45:2.5.

[0016] Optionally, the silane coupling agent is selected from one or more of methyltributanone oxime silane, 3-aminopropyltriethoxysilane, vinyltributanone oxime silane, propyltrimethoxysilane, and aminoethylaminopropyltrimethoxysilane.

[0017] Optionally, the silane coupling agent is a mixture of methyltributanone oxime silane, 3-aminopropyltriethoxysilane, vinyltributanone oxime silane, propyltrimethoxysilane, and aminoethylaminopropyltrimethoxysilane.

[0018] Optionally, based on the weight of the high-strength insulating coating, it comprises the following components in parts by weight: 3-5 parts of methyl tributanone oxime silane, 0.3-0.5 parts of 3-aminopropyltriethoxysilane, 1.5-2.0 parts of vinyl tributanone oxime silane, 0.3-0.7 parts of propyltrimethoxysilane, and 0.3-0.5 parts of aminoethylaminopropyltrimethoxysilane.

[0019] Secondly, this application provides a method for preparing a high-strength insulating coating, comprising the following steps: weighing each component according to the weight parts, mixing them evenly, and obtaining a high-strength insulating coating.

[0020] In summary, this application has the following beneficial effects: 1. This application uses polydimethylsiloxane with a viscosity of 18000-22000cp as the matrix, and combines it with tungsten oxide, chitosan-modified montmorillonite and black phosphorus as composite nanofillers in a weight ratio of 1:(0.1-0.8):(1.5-4). This results in a high-strength insulating coating with high mechanical strength, good insulation and excellent adhesion to the substrate surface. The coating can still maintain excellent mechanical strength and film adhesion under extreme environments such as high temperature and high humidity, and has good application prospects.

[0021] 2. In this application, the weight ratio of tungsten oxide, chitosan-modified montmorillonite, and black phosphorus in the composite nanofiller is controlled within the range of 1:(0.3-0.6):(2-3), and the amount added is controlled between 1 and 2 parts. The resulting high-strength insulating coating has better performance. The electrical breakdown strength of the coating film after film formation is 32.1-32.8 kV / mm (≥32 kV / mm), the initial tensile strength is 25.6-27.2 MPa (≥25.0 MPa), and the adhesion grade on the substrate surface is 0. After testing under simulated extreme environment, the tensile strength of the coating film is 22.0-23.9 MPa (≥22.0 kV / mm), and the adhesion grade on the substrate surface is 0. Detailed Implementation

[0022] This application provides a high-strength insulating coating comprising the following components in parts by weight: 30-40 parts of polydimethylsiloxane with a viscosity of 18000-22000cp, 3-5 parts of methyl tributanone oxime silane, 0.3-0.5 parts of 3-aminopropyltriethoxysilane, 1.5-2.0 parts of vinyl tributanone oxime silane, 0.3-0.7 parts of propyltrimethoxysilane and 0.3-0.5 parts of aminoethylaminopropyltrimethoxysilane, 0.5-3 parts of composite nanofiller, 15-20 parts of aluminum hydroxide, 10-15 parts of silica, 0.2-0.5 parts of dibutyltin dilaurate, and 40-45 parts of diluent; The composite nanofiller is tungsten oxide, chitosan-modified montmorillonite, and black phosphorus in a weight ratio of 1:(0.1-0.8):(1.5-4); further, the weight ratio of tungsten oxide, chitosan-modified montmorillonite, and black phosphorus is 1:(0.3-0.6):(2-3). This application also provides a method for preparing the above-mentioned high-strength insulating coating, including the following steps: weighing each component according to the weight parts, mixing them evenly, and obtaining the high-strength insulating coating.

[0023] The method for preparing chitosan-modified montmorillonite in this application includes the following steps: (1) First, add 10-15 times the amount of deionized water to montmorillonite, stir at high speed at 800-1000 r / min for 30-60 min, then centrifuge and wash to obtain a purified montmorillonite suspension; then calcine it at 500-600℃ for 2-3 h, cool it, grind it, and pass it through a 200-mesh sieve to obtain pretreated montmorillonite; (2) Add 1-2% glacial acetic acid to deionized water, adjust the pH to 3-4, and slowly add chitosan powder under stirring at 40-50℃ and 500-600r / min, controlling the mass volume concentration of chitosan in the solution to be 0.2-0.4g / mL; continue stirring for 1-2h, and filter through a 300-mesh filter cloth to obtain a transparent and uniform chitosan acetic acid solution.

[0024] (3) According to the weight ratio of montmorillonite to chitosan of 1:(0.2-0.5), the pretreated montmorillonite is added to the chitosan acetic acid solution and stirred at 50-60℃ and 600-800r / min for 2-4h. During the process, the pH of the system is adjusted to 6.5-7.5 with 5% sodium hydroxide solution. After the reaction is completed, the mixture is centrifuged at 4000-5000r / min for 20-30min and the precipitate is collected. After repeated washing with deionized water, grinding with a ball mill and passing through a 1000-mesh sieve, chitosan modified montmorillonite is obtained.

[0025] The raw materials, reagents, solvents, etc. used in this application can all be obtained commercially.

[0026] The following describes this application in further detail with reference to preparation examples, embodiments, and performance testing. Preparation Example 1

[0027] Preparation Example 1 provides a method for preparing chitosan-modified montmorillonite as follows: (1) First, add 100g of deionized water to 10g of montmorillonite (300 mesh), stir at 1000r / min for 30min, then centrifuge and wash to obtain a purified montmorillonite suspension; then calcine it at 550℃ for 2h, cool it, grind it and pass it through a 200 mesh sieve to obtain pretreated montmorillonite. (2) Add 1.5% glacial acetic acid to 10 mL of deionized water, adjust the pH to 3.5, and slowly add 3 g of chitosan powder under stirring at 50℃ and 500 r / min, controlling the mass volume concentration of chitosan in the solution to be 0.3 g / mL; continue stirring for 2 h, and filter through a 300 mesh filter cloth to obtain a transparent and uniform chitosan acetic acid solution.

[0028] (3) According to the weight ratio of montmorillonite to chitosan of 1:0.3, the pretreated montmorillonite was added to the chitosan acetic acid solution and stirred at 55℃ and 600r / min for 3h. During the process, the pH of the system was adjusted to 7 with 5% sodium hydroxide solution. After the reaction was completed, the mixture was centrifuged at 4000r / min for 30min and the precipitate was collected. After repeated washing with deionized water, grinding with a ball mill and passing through a 1000-mesh sieve, chitosan modified montmorillonite was obtained. Example 1

[0029] Example 1 provides a high-strength insulating coating.

[0030] The preparation method of the above-mentioned high-strength insulating coating is as follows: Weigh out 35g of polydimethylsiloxane with a viscosity of 20000cp, 4g of methyl tributanone oxime silane, 0.4g of 3-aminopropyltriethoxysilane, 1.8g of vinyl tributanone oxime silane, 0.5g of propyltrimethoxysilane and 0.4g of aminoethylaminopropyltrimethoxysilane, 2g of composite nanofiller, 17.5g of aluminum hydroxide, 12.5g of silicon dioxide, 0.35g of dibutyltin dilaurate and 42.5g of xylene, and mix them evenly to obtain the high-strength insulating coating. Example 2

[0031] Example 2 provides a high-strength insulating coating.

[0032] The preparation method of the above-mentioned high-strength insulating coating is as follows: 40g of polydimethylsiloxane with a viscosity of 20000cp, 4.7g of methyl tributanone oxime silane, 0.3g of 3-aminopropyltriethoxysilane, 1.5g of vinyl tributanone oxime silane, 0.3g of propyltrimethoxysilane and 0.3g of aminoethylaminopropyltrimethoxysilane, 2g of composite nanofiller, 15g of aluminum hydroxide, 15g of silicon dioxide, 0.45g of dibutyltin dilaurate and 45g of xylene are weighed and mixed evenly to obtain the high-strength insulating coating. Example 3

[0033] Example 3 provides a high-strength insulating coating.

[0034] The preparation method of the above-mentioned high-strength insulating coating is as follows: Weigh out 30g of polydimethylsiloxane with a viscosity of 20000cp, 3.5g of methyl tributanone oxime silane, 0.5g of 3-aminopropyltriethoxysilane, 2.0g of vinyl tributanone oxime silane, 0.6g of propyltrimethoxysilane and 0.5g of aminoethylaminopropyltrimethoxysilane, 2g of composite nanofiller, 20g of aluminum hydroxide, 10g of silicon dioxide, 0.45g of dibutyltin dilaurate and 40g of xylene, and mix them evenly to obtain the high-strength insulating coating. Examples 4-6

[0035] Examples 4-6 each provide a high-strength insulating coating.

[0036] The difference between the above embodiments and Embodiment 1 is that: in Embodiment 4, the amount of composite nanofiller added is 0.5g; in Embodiment 5, the amount of composite nanofiller added is 1g; and in Embodiment 6, the amount of composite nanofiller added is 3g. Examples 7-14

[0037] Examples 7-14 each provide a high-strength insulating coating.

[0038] The difference between the above embodiments and Embodiment 1 lies in the type and ratio of the composite nanofiller, as shown in Table 1 below.

[0039] Table 1. Types and proportions of composite nanofillers in Examples 1 and 7-14 Comparative Example 1

[0040] Comparative Example 1 provides a high-strength insulating coating.

[0041] The difference between the above comparative example and Example 1 is that the composite nanofiller uses tungsten oxide and black phosphorus in a weight ratio of 1.45:2.5. Comparative Example 2

[0042] Comparative Example 2 provides a high-strength insulating coating.

[0043] The difference between the above comparative example and Example 1 is that the composite nanofiller uses chitosan-modified montmorillonite and black phosphorus in a weight ratio of 1.45:2.5. Comparative Example 3

[0044] Comparative Example 3 provides a high-strength insulating coating.

[0045] The difference between the above comparative example and Example 1 is that the composite nanofiller uses tungsten oxide, chitosan-modified montmorillonite, and black phosphorus in a weight ratio of 1:1:1. Comparative Example 4

[0046] Comparative Example 4 provides a high-strength insulating coating.

[0047] The difference between the above comparative example and Example 1 is that the composite nanofiller uses tungsten oxide, carbon nanotubes and graphene in a ratio of 1:0.45:2.5. Comparative Example 5

[0048] Comparative Example 5 provides a high-strength insulating coating.

[0049] The difference between the above comparative example and Example 1 is that the polydimethylsiloxane with a viscosity of 20000cp was replaced with polydimethylsiloxane with a viscosity of 1500cp. Performance testing experiment

[0050] The high-strength insulating coatings obtained in Examples 1-14 and Comparative Examples 1-5 were subjected to various performance tests, and the results are shown in Table 2 below.

[0051] (1) Tensile strength: High-strength insulating coating was applied to a polytetrafluoroethylene release plate to form a coating film with a thickness of 2±0.2mm. The film was cut into I-shaped dumbbell specimens with a gauge length of 6±0.2mm and a gauge length of 25mm. The initial tensile strength of the coating film was tested using an electronic universal testing machine. The coating film was then placed in a constant temperature and humidity test chamber with environmental conditions of 60℃ and 80%RH. After standing for 1000h, the film was taken out, cooled to room temperature, and placed for 2h. The tensile strength after simulating extreme environment was tested using the same method as above. The tensile strength test was performed by averaging 5 valid specimens.

[0052] (2) Electrical breakdown strength: Prepare a coating with a thickness of 0.1±0.02mm and cut the coating into square samples of 50mm×50mm; use a power frequency breakdown voltage tester to test the electrical breakdown strength of the coating: use brass electrodes, with an upper electrode diameter of 25mm, a lower electrode diameter of 50mm, and an electrode edge radius of 2mm; test 3 different points for each sample, take the breakdown voltage values ​​of all valid test points, calculate the breakdown strength and take the average value.

[0053] (3) Adhesion: The high-strength insulating coating was applied to the epoxy resin board (FR-4) substrate to form a wet film with a thickness of 100±5μm. It was cured at 70℃ for 24h and then cooled to room temperature. The adhesion level of the coating on the substrate surface was then tested by cross-cut test. Next, it was placed in a constant temperature and humidity test chamber with environmental conditions of 60℃ and 80%RH. After standing for 1000h, it was taken out, cooled to room temperature and placed for 2h. The adhesion level of the coating was tested again.

[0054] Table 2 Performance test results of high-strength insulating coatings obtained in Examples 1-14 and Comparative Examples 1-5

[0055] According to the test results in Table 2, the high-strength insulating coatings obtained in Examples 1-14 have an electrical breakdown strength of 30.6-33.0 kV / mm and an initial tensile strength of 20.4-27.2 MPa after film formation, with an adhesion grade of 0 on the substrate surface. After testing in simulated extreme environments, the tensile strength of the coating is 17.1-24.7 MPa, with an adhesion grade of 0-1 on the substrate surface. In contrast, the high-strength insulating coatings obtained in Comparative Examples 1-5 have an initial tensile strength of only 15.2-18.7 MPa after film formation, with an adhesion grade of 0-1 on the substrate surface. After testing in simulated extreme environments, the tensile strength of the coating is only 12.8-15.9 MPa, with an adhesion grade of 0-2 on the substrate surface. Therefore, this application demonstrates that by using polydimethylsiloxane with a viscosity of 18000-22000cp as the matrix and combining it with tungsten oxide, chitosan-modified montmorillonite, and black phosphorus as composite nanofillers in a weight ratio of 1:(0.1-0.8):(1.5-4), a high-strength insulating coating with high mechanical strength, good insulation, and excellent adhesion to the substrate surface can be obtained. This coating can still maintain excellent mechanical strength and film adhesion under extreme environments such as high temperature and high humidity, and has good application prospects.

[0056] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A high-strength insulating coating, characterized in that, It comprises the following components in parts by weight: 30-40 parts of polydimethylsiloxane with a viscosity of 18000-22000cp, 4-10 parts of silane coupling agent, 0.5-3 parts of composite nanofiller, 15-20 parts of aluminum hydroxide, 10-15 parts of silica, 0.2-0.5 parts of dibutyltin dilaurate, and 40-45 parts of diluent; The composite nanofiller is tungsten oxide, chitosan-modified montmorillonite, and black phosphorus in a weight ratio of 1:(0.1-0.8):(1.5-4).

2. The high-strength insulating coating according to claim 1, characterized in that, The high-strength insulating coating comprises the following components in parts by weight: 35 parts of polydimethylsiloxane with a viscosity of 20000cp, 7.1 parts of silane coupling agent, 2 parts of composite nanofiller, 17.5 parts of aluminum hydroxide, 12.5 parts of silicon dioxide, 0.35 parts of dibutyltin dilaurate, and 42.5 parts of diluent.

3. The high-strength insulating coating according to claim 1, characterized in that, The weight ratio of tungsten oxide, chitosan-modified montmorillonite, and black phosphorus is 1:(0.3-0.6):(2-3).

4. The high-strength insulating coating according to claim 1, characterized in that, The weight ratio of tungsten oxide, chitosan-modified montmorillonite, and black phosphorus is 1:0.45:2.

5.

5. The high-strength insulating coating according to claim 1, characterized in that, The silane coupling agent is selected from one or more of methyl tributanone oxime silane, 3-aminopropyltriethoxysilane, vinyl tributanone oxime silane, propyltrimethoxysilane, and aminoethylaminopropyltrimethoxysilane.

6. The high-strength insulating coating according to claim 1, characterized in that, The silane coupling agent is a mixture of methyl tributanone oxime silane, 3-aminopropyltriethoxysilane, vinyl tributanone oxime silane, propyltrimethoxysilane, and aminoethylaminopropyltrimethoxysilane.

7. The high-strength insulating coating according to claim 1, characterized in that, Based on the weight of the high-strength insulating coating, it contains the following components in parts by weight: 3-5 parts of methyl tributanone oxime silane, 0.3-0.5 parts of 3-aminopropyltriethoxysilane, 1.5-2.0 parts of vinyl tributanone oxime silane, 0.3-0.7 parts of propyltrimethoxysilane, and 0.3-0.5 parts of aminoethylaminopropyltrimethoxysilane.

8. A method for preparing a high-strength insulating coating as described in any one of claims 1-7, characterized in that, Includes the following steps: Weigh each component according to its weight percentage, mix them evenly, and obtain a high-strength insulating coating.

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