High-temperature-resistant enameled wire insulating coating and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant enameled wire insulating coating and a preparation method thereof, and relates to the technical field of insulating coatings. The insulating coating of the high-temperature-resistant enameled wire comprises the following raw materials in parts by weight: 40-50 parts of polyamide-imide resin, 20-30 parts of fluororesin, 5-10 parts of nano silicon dioxide, 10-15 parts of silicon nitride, 5-8 parts of aluminum nitride, 300 parts of a solvent, 0.5-1.5 parts of a surfactant, 1-3 parts of a modified tackifier and 1-2.5 parts of an antioxidant. The high-temperature-resistant enameled wire insulating coating prepared by the invention has good adhesive force and oxidation resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of insulating coatings, and in particular to a high-temperature resistant enameled wire insulating coating and a preparation method thereof. Background Art

[0002] As a key material in motors, electrical appliances, transformers, and electronic equipment, enameled wire's performance is directly related to the reliability and service life of these devices. The insulating varnish layer, the core component of enameled wire, must possess excellent insulation properties, high mechanical strength, heat resistance, and adhesion to ensure long-term, stable operation under various complex operating conditions.

[0003] With the continuous development of modern industry and technology, the requirements for materials in high-temperature environments are becoming increasingly stringent. Critical equipment such as aerospace engines, electric vehicle motors, industrial motors, and transformers must operate stably and for extended periods in high-temperature environments. Traditional insulating varnish materials, such as polyester and polyurethane varnishes, perform well in medium and low-temperature environments. However, they are susceptible to thermal degradation in high-temperature environments, resulting in a significant decrease in insulation performance and even potential safety hazards, making them difficult to meet these demanding application scenarios. In addition to high-temperature environments, equipment in many industrial applications must also cope with complex chemical corrosion environments. In places like chemical plants, marine engineering projects, and nuclear power plants, equipment is exposed to corrosive substances such as acids, alkalis, solvents, and salt spray. These substances can severely damage traditional insulating varnishes, causing insulation failure and, in turn, compromising the safety and reliability of the equipment.

[0004] Chinese invention patent publication number CN118600356A discloses a composite insulating coating for an alloy substrate surface and a preparation method thereof. The composite insulating coating includes a transition layer, a ceramic layer, and a surface layer prepared on the surface of the alloy substrate. The composite insulating coating has excellent insulating and corrosion resistance, but its aging resistance is poor. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention aims to provide a high-temperature resistant enameled wire insulation coating and a preparation method thereof.

[0006] To achieve the above object, the present invention is implemented through the following technical solutions: A high-temperature resistant enameled wire insulation coating comprises the following raw materials in parts by weight: 40-50 parts of polyamide-imide resin, 20-30 parts of fluororesin, 5-10 parts of nano-silicon dioxide, 10-15 parts of silicon nitride, 5-8 parts of aluminum nitride, 300 parts of solvent, 0.5-1.5 parts of surfactant, 1-3 parts of modified tackifier, and 1-2.5 parts of antioxidant; The modified tackifier is prepared by the following method: S1: 2,6-dibromo-4-(trifluoromethoxy)aniline and 1H,1H-perfluoro-1-decanol react in the presence of potassium carbonate to form a two-arm fluorinated compound; S2: tribromoacetic acid and N-dodecyl imidazole react to form a cationic imidazole compound; S3: The dual-arm fluorinated compound and the cationic imidazole compound react under the action of EDC / NHS to form a modified tackifier.

[0007] In the step S1, the molar ratio of 2,6-dibromo-4-(trifluoromethoxy)aniline to 1H,1H-perfluoro-1-decanol is 1:(2-3).

[0008] The molar ratio of tribromoacetic acid to N-dodecyl imidazole in step S2 is 1:(3-5).

[0009] In step S3, the molar ratio of the double-arm fluorine-containing compound to the cationic imidazole compound is (1-1.5):1.

[0010] The solvent is one of 1,4-butyrolactone and propylene carbonate.

[0011] The surfactant is one of stearic acid, oleic acid and lauric acid.

[0012] The antioxidant is prepared by the following method: A1: Allyloxy polyoxyethylene ether and trimethylolpropane tris(3-mercaptopropionate) react under the action of initiator AIBN to form a three-arm thiol compound; A2: A three-arm thiol compound reacts with 1,3-bis(4-benzoyl-3-hydroxyphenoxy)-2-methylacrylate in the presence of catalyst C-94 and 1-butyl-3-methylimidazolium methanesulfonate ionic liquid to generate an antioxidant.

[0013] In the step A1, the mass ratio of allyloxypolyoxyethylene ether to trimethylolpropane tris(3-mercaptopropionate) is 8:1.

[0014] In the step A2, the mass ratio of the three-arm thiol compound to 1,3-bis(4-benzoyl-3-hydroxyphenoxy)-2-propyl methylacrylate is 2.5:1.

[0015] A method for preparing a high-temperature resistant enameled wire insulation coating comprises the following steps: (1) Weigh by weight: 40-50 parts of polyamide-imide resin, 20-30 parts of fluororesin, 5-10 parts of nano-silicon dioxide, 10-15 parts of silicon nitride, 5-8 parts of aluminum nitride, 300 parts of solvent, 0.5-1.5 parts of surfactant, 1-3 parts of modified tackifier, and 1-2.5 parts of antioxidant; (2) Nano-silicon dioxide, silicon nitride, and aluminum nitride are mixed in proportion, a surfactant and 80 parts of solvent are added, and the mixture is dispersed by high-speed shearing to form a pre-treated filler; polyamide-imide resin is mixed with the remaining solvent, heated to 60-70°C, stirred and mixed, fluororesin is added, heated to 80-90°C, and stirred to form a homogeneous resin liquid; the pre-treated filler, modified tackifier, and antioxidant are added to the homogeneous resin liquid in sequence, sheared at high speed, and passed through a 400-mesh sieve to obtain a composite coating material; (3) The composite coating material is dipped onto the surface of the copper wire, and then pre-baked, initially cured, and cured to obtain a high-temperature resistant enameled wire insulation coating.

[0016] Due to the adoption of the above technical solution, the beneficial effects of the present invention include: (1) The modified tackifier prepared by the present invention achieves a balance between high adhesion and high tensile strength in the high-temperature resistant enameled wire insulation coating through the synergistic effect of the rigidity enhancement of the fluorocarbon chain and the electrostatic adsorption of the cationic imidazole ring. At the same time, it has excellent high-temperature stability and chemical durability, and is suitable for the insulation protection needs under harsh working conditions.

[0017] (2) The antioxidant prepared by the present invention realizes a triple anti-aging mechanism of free radical scavenging, UV shielding, and thermal stability enhancement through the multifunctional design of the chemical structure. At the same time, it ensures long-term effectiveness by virtue of its high molecular weight and topological structure. It is particularly suitable for enameled wire insulation coating in high temperature and strong UV radiation environment, and can significantly extend the service life of the coating. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0019] Example 1 Preparation of modified tackifier: S1: Under nitrogen protection, 500 ml of N,N-dimethylacetamide, 0.2 mol of 1H,1H-perfluoro-1-decanol, and 50 g of anhydrous K2CO3 were added to the reactor, stirred and mixed, and the temperature was raised to 80°C. Then, 0.1 mol of 2,6-dibromo-4-(trifluoromethoxy)aniline was added in batches (0.05 mol per batch, with a batch interval of 20 min). After reacting for 10 h, the temperature was cooled to room temperature, 100 ml of anhydrous ethanol and 600 ml of deionized water were added, stirred, and the precipitate was precipitated and filtered. Then, the precipitate was washed three times with deionized water (100 ml of deionized water each time), and then 300 ml of anhydrous ethanol was added for recrystallization. The product was dried under vacuum at 70°C for 2 h to obtain a double-arm fluorine-containing compound. The reaction equation is shown below:

[0020] S2: Add 400 ml of acetonitrile and 0.3 mol of N-dodecyl imidazole to the reactor, stir and mix, heat to 50° C., then add 0.1 mol of tribromoacetic acid, reflux for 4 hours, distill under reduced pressure at 60° C. for 2 hours, and vacuum dry at 60° C. for 5 hours to obtain a cationic imidazole compound; the reaction equation is as follows:

[0021] S3: Add 1000 ml of a DMF / DMSO (DMF:DMSO (V / V) = 1:1) mixed solvent and 0.1 mol of a cationic imidazole compound to a reactor. Then, add 0.12 mol of EDC and 0.12 mol of NHS. Stir and activate at room temperature for 30 minutes. Slowly add 0.1 mol of a double-arm fluorinated compound (0.05 mol per batch, with a 20-minute interval between batches). After reacting at room temperature for 8 hours, filter, wash the filter cake three times with 200 ml of a saturated NaHCO solution, and dry it in a vacuum at 60°C for 4 hours to obtain a modified tackifier. The reaction equation is as follows:

[0022] Its H-NMR spectrum data are as follows: 1 H NMR (500 MHz, Chloroform-d) δ 10.27 (tt, J = 1.7, 0.8 Hz, 3H), 9.18 (s, 1H), 7.70 (dd, J = 5.0, 1.7 Hz, 3H), 7.63 (ddt, J = 5.0, 1.7, 0.8Hz, 3H), 6.65 (s, 2H), 4.78 (tt, J = 13.0, 2.7 Hz, 4H), 4.03 (tt, J = 6.2,0.9 Hz, 6H), 1.74 – 1.65 (m, 6H), 1.34 – 1.24 (m, 54H), 0.94 – 0.85 (m, 9H). Example 2 Preparation of modified tackifier: S1: Under nitrogen protection, 500 ml of N,N-dimethylacetamide, 0.25 mol of 1H,1H-perfluoro-1-decanol, and 50 g of anhydrous K2CO3 were added to the reactor, stirred and mixed, and the temperature was raised to 85°C. Then, 0.1 mol of 2,6-dibromo-4-(trifluoromethoxy)aniline was added in batches (0.05 mol per batch, with a batch interval of 20 min). After reacting for 9 hours, the temperature was cooled to room temperature, 100 ml of anhydrous ethanol and 600 ml of deionized water were added, stirred, and the precipitate was precipitated. The precipitate was filtered and washed three times with deionized water (100 ml of deionized water each time). Then, 300 ml of anhydrous ethanol was added for recrystallization, and the product was dried under vacuum at 70°C for 2 hours to obtain a double-arm fluorine-containing compound. S2: Add 400 ml of acetonitrile and 0.4 mol of N-dodecyl imidazole to the reactor, stir and mix, heat to 60°C, then add 0.1 mol of tribromoacetic acid, reflux for 3 h, distill under reduced pressure at 65°C for 2 h, and dry under vacuum at 60°C for 5 h to obtain a cationic imidazole compound; S3: Add 1000 ml of DMF / DMSO (DMF:DMSO (V / V) = 1:1) mixed solvent and 0.1 mol of cationic imidazole compound to the reactor, then add 0.12 mol of EDC and 0.12 mol of NHS, stir and activate at room temperature for 50 minutes, slowly add 0.12 mol of double-arm fluorinated compound (0.05 mol per batch, batch interval of 20 minutes), react at room temperature for 7 hours, filter, wash the filter cake three times with 200 ml of saturated NaHCO3 solution, and dry in vacuum at 60°C for 4 hours to obtain a modified thickener.

[0023] Example 3 Preparation of modified tackifier: S1: Under nitrogen protection, 500 ml of N,N-dimethylacetamide, 0.3 mol of 1H,1H-perfluoro-1-decanol, and 50 g of anhydrous K2CO3 were added to the reactor, stirred and mixed, and the temperature was raised to 100°C. Then, 0.1 mol of 2,6-dibromo-4-(trifluoromethoxy)aniline was added in batches (0.05 mol per batch, with a batch interval of 20 min). After reacting for 8 h, the temperature was cooled to room temperature, 100 ml of anhydrous ethanol and 600 ml of deionized water were added, stirred, and the precipitate was precipitated. The precipitate was filtered and washed three times with deionized water (100 ml of deionized water each time). Then, 300 ml of anhydrous ethanol was added for recrystallization, and the mixture was dried under vacuum at 70°C for 2 h to obtain a double-arm fluorine-containing compound; S2: Add 400 ml of acetonitrile and 0.5 mol of N-dodecyl imidazole to the reactor, stir and mix, heat to 70°C, then add 0.1 mol of tribromoacetic acid, reflux for 2 h, distill under reduced pressure at 60°C for 2.5 h, and dry under vacuum at 60°C for 5 h to obtain a cationic imidazole compound; S3: Add 1000 ml of DMF / DMSO (DMF:DMSO (V / V) = 1:1) mixed solvent and 0.1 mol of cationic imidazole compound to the reactor, then add 0.12 mol of EDC and 0.12 mol of NHS, stir and activate at room temperature for 60 minutes, slowly add 0.15 mol of double-arm fluorinated compound (0.05 mol per batch, batch interval of 20 minutes), react at room temperature for 6 hours, filter, wash the filter cake three times with 200 ml of saturated NaHCO3 solution, and dry in vacuum at 60°C for 4 hours to obtain a modified tackifier.

[0024] Example 4 Preparation of antioxidant: A1: Under nitrogen protection, 500g DMSO, 10g trimethylolpropane tris(3-mercaptopropionate), and 80g allyloxypolyoxyethylene ether (APEG-1000) were added to the reactor, stirred and mixed, and the temperature was raised to 80°C. Then, 10g initiator AIBN was added. After reacting for 24h, the mixture was distilled under reduced pressure at 60°C for 3h. The three-arm thiol compound was separated by silica gel column. The reaction equation is as follows:

[0025] A2: Under nitrogen, 300 g of DMF, 50 g of a three-arm thiol compound, 20 g of 1,3-bis(4-benzoyl-3-hydroxyphenoxy)-2-methylacrylate, 8 g of catalyst C-94, and 3.5 g of 1-butyl-3-methylimidazolium methanesulfonate ionic liquid were added to a reactor in sequence. The mixture was stirred and evenly mixed. The temperature was raised to 100°C and allowed to react for 4 h. The temperature was then lowered to room temperature. 400 g of deionized water was added and stirred evenly. The mixture was centrifuged and filtered. The mixture was washed with 60 g of anhydrous ethanol and then 60 g of deionized water. The mixture was dried under vacuum at 50°C for 10 h to obtain an antioxidant. The reaction equation is as follows:

[0026] Example 5 Preparation of high temperature resistant enameled wire insulation coating: (1) Weigh: 400 g of polyamide-imide resin, 200 g of fluororesin, 50 g of nano-silica, 100 g of silicon nitride, 50 g of aluminum nitride, 3000 g of solvent (1,4-butyrolactone), 5 g of surfactant (stearic acid), 10 g of modified tackifier (prepared in Example 1), and 10 g of antioxidant (prepared in Example 4); (2) Nano-silicon dioxide, silicon nitride, and aluminum nitride were mixed in proportion, surfactants and 800 g of solvent were added, and high-speed shearing and dispersion were carried out at 3000 rpm for 45 min to form a pretreated filler; polyamide-imide resin was mixed with the remaining solvent, heated to 60 ° C, stirred for 2 h until completely dissolved, fluororesin was added, heated to 80 ° C, and stirred for 40 min to form a homogeneous resin liquid; pretreated filler, modified tackifier, and antioxidant were added to the homogeneous resin liquid in sequence, high-speed shearing (3000 rpm) for 1 h, and passed through a 400-mesh sieve to obtain a composite coating material; (3) The copper wire was dipped into the composite coating material at a speed of 3 m / min, with a wet film thickness of 120 μm; then pre-baked at 120 °C for 20 min, initially cured at 220 °C for 30 min, and cured at 320 °C for 1 h to obtain a high-temperature resistant enameled wire insulation coating.

[0027] Example 6 Preparation of high temperature resistant enameled wire insulation coating: (1) Weigh: 450 g of polyamide-imide resin, 250 g of fluororesin, 80 g of nano-silica, 120 g of silicon nitride, 60 g of aluminum nitride, 3000 g of solvent (1,4-butyrolactone), 10 g of surfactant (oleic acid), 20 g of modified tackifier (prepared in Example 2), and 20 g of antioxidant (prepared in Example 4); (2) Nano-silicon dioxide, silicon nitride, and aluminum nitride were mixed in proportion, surfactants and 800 g of solvent were added, and high-speed shearing and dispersion at 3000 rpm was performed for 40 min to form a pretreated filler; polyamide-imide resin was mixed with the remaining solvent, heated to 65 ° C, stirred for 2 h until completely dissolved, fluororesin was added, heated to 85 ° C, and stirred for 30 min to form a homogeneous resin liquid; pretreated filler, modified tackifier, and antioxidant were added to the homogeneous resin liquid in sequence, high-speed shearing (3000 rpm) for 1 h, and passed through a 400-mesh sieve to obtain a composite coating material; (3) The copper wire was dipped into the composite coating material at a speed of 3 m / min, with a wet film thickness of 100 μm; then pre-baked at 120 °C for 20 min, initially cured at 220 °C for 30 min, and cured at 320 °C for 1 h to obtain a high-temperature resistant enameled wire insulation coating.

[0028] Example 7 Preparation of high temperature resistant enameled wire insulation coating: (1) Weigh: 500 g of polyamide-imide resin, 300 g of fluororesin, 100 g of nano-silica, 150 g of silicon nitride, 80 g of aluminum nitride, 3000 g of solvent (propylene carbonate), 15 g of surfactant (lauric acid), 30 g of modified tackifier (prepared in Example 3), and 25 g of antioxidant (prepared in Example 4); (2) Nano-silicon dioxide, silicon nitride, and aluminum nitride were mixed in proportion, surfactants and 800 g of solvent were added, and high-speed shearing and dispersion were carried out at 3000 rpm for 45 min to form a pretreated filler; polyamide-imide resin was mixed with the remaining solvent, heated to 70 ° C, stirred for 2 h until completely dissolved, fluororesin was added, heated to 90 ° C, and stirred for 40 min to form a homogeneous resin liquid; pretreated filler, modified tackifier, and antioxidant were added to the homogeneous resin liquid in sequence, high-speed shearing (3000 rpm) for 1 h, and passed through a 400-mesh sieve to obtain a composite coating material; (3) The copper wire was dipped into the composite coating material at a speed of 3 m / min, with a wet film thickness of 120 μm; then pre-baked at 120 °C for 20 min, initially cured at 220 °C for 30 min, and cured at 320 °C for 1 h to obtain a high-temperature resistant enameled wire insulation coating.

[0029] Comparative Example 1 The raw material composition and process of the high temperature resistant enameled wire insulation coating are basically the same as those in Example 6, except that the modified tackifier is replaced by an equal weight of a modified tackifier prepared by the following method: The preparation method of the modified tackifier of this comparative example is basically the same as that of Example 2, except that the 1H,1H-perfluoro-1-decanol added in step S1 is replaced by an equal weight of 1H,1H-perfluorooctadecane-1-ol.

[0030] Comparative Example 2 The raw material composition and process of the high temperature resistant enameled wire insulation coating are basically the same as those in Example 6, except that the modified tackifier is replaced by an equal weight of a modified tackifier prepared by the following method: The preparation method of the modified tackifier of this comparative example is basically the same as that of Example 2, except that the 2,6-dibromo-4-(trifluoromethoxy)aniline added in step S1 is replaced by an equal weight of p-bromoaniline.

[0031] Comparative Example 3 The raw material composition and process of the high-temperature resistant enameled wire insulation coating are basically the same as those in Example 6, except that the modified tackifier is replaced by an equal weight of a modified tackifier prepared by the following method: The preparation method of the modified tackifier in this comparative example is substantially the same as that in Example 2, except that the tribromoacetic acid added in step S2 is replaced by an equal weight of 2,3-dibromosuccinic acid.

[0032] Comparative Example 4 The raw material composition and process of the high-temperature resistant enameled wire insulation coating are basically the same as those in Example 6, except that the modified tackifier is replaced by an equal weight of a modified tackifier prepared by the following method: The preparation method of the modified tackifier in this comparative example is basically the same as that in Example 2, except that the N-dodecyl imidazole added in step S2 is replaced by an equal weight of N-butyl imidazole.

[0033] Comparative Example 5 The raw material composition and process of the high-temperature resistant enameled wire insulation coating are basically the same as those in Example 6, except that the antioxidant is replaced by an antioxidant prepared by the following method in an equal weight: The preparation method of the antioxidant in this comparative example is basically the same as that in Example 4, except that the allyloxypolyoxyethylene ether added in step A1 is replaced by an equal weight of diethylene glycol monovinyl ether.

[0034] Comparative Example 6 The raw material composition and process of the high-temperature resistant enameled wire insulation coating are basically the same as those in Example 6, except that the antioxidant is replaced by an antioxidant prepared by the following method in an equal weight: The preparation method of the antioxidant in this comparative example is basically the same as that in Example 4, except that the trimethylolpropane tris(3-mercaptopropionate) added in step A1 is replaced by an equal weight of pentaerythritol tetrakis(3-mercaptopropionate).

[0035] Comparative Example 7 The raw material composition and process of the high-temperature resistant enameled wire insulation coating are basically the same as those in Example 6, except that the antioxidant is replaced by an antioxidant prepared by the following method in an equal weight: The preparation method of the antioxidant in this comparative example is basically the same as that in Example 4, except that the 1,3-bis(4-benzoyl-3-hydroxyphenoxy)-2-methylacrylate added in step A2 is replaced by an equal weight of 2-hydroxy-4-(methacryloyloxy)benzophenone.

[0036] The polyamide-imide resin used in the examples and comparative examples of this application is Torlon 4301, produced by Solvay Group; the fluororesin is F-208L, produced by Daikin Fluorochemical (China) Co., Ltd.; the nanosilica is As-200, produced by Shenyang Chemical Co., Ltd.; the silicon nitride is XH-Si3N4-20, produced by Shanghai Xiaohuang Nanotechnology Co., Ltd.; and the aluminum nitride is XH-AlN-50, produced by Shanghai Xiaohuang Nanotechnology Co., Ltd. The copper wire used in this application is a hard round copper bare wire with a diameter of 3.00 mm.

[0037] The composite coating material / high-temperature resistant enameled wire insulation coating prepared in the examples of the present application and the comparative examples were subjected to performance tests, and the test results are shown in Table 1.

[0038] Adhesion grade performance testing was conducted according to GB / T 1720-2020, using a 120 mm × 50 mm × 0.5 mm copper plate as the substrate. Adhesion of the insulating coating was tested according to the peel test method in GB / T 4074.3-2008. Tensile strength was tested according to GB / T 1040.1-2006, using aging conditions of 10 days in an aging chamber at 150°C and 95% humidity. Volume resistivity was tested according to GB / T 1410-2006 at a test voltage of 250 V. The test results are shown in Table 1.

[0039] Table 1 Performance test table

[0040] It can be seen from Table 1 that the high-temperature resistant enameled wire insulation coating prepared in the embodiment of the present application has excellent adhesion, insulation performance and aging resistance.

[0041] The cationic imidazole groups in the modified tackifier prepared by the present invention can tightly bind to the negatively charged areas on the surface of the copper wire through electrostatic attraction, thereby improving the adhesion between the coating and the substrate. The long carbon chain introduced by N-dodecyl imidazole increases the flexibility of the adhesive, making it easier to adapt to the micromorphology of the substrate surface, increasing the contact area, and reducing interfacial stress concentration. The high bond energy of the C-F bond imparts excellent heat resistance and mechanical strength to the coating, while the rigid structure of the perfluoroalkyl chain inhibits molecular chain slip and enhances tensile strength. The flexibility of the dodecyl chain complements the rigidity of the fluorocarbon chain, preventing brittle fracture while enhancing overall toughness through intermolecular forces (such as van der Waals forces).

[0042] The phenolic hydroxyl group in 1,3-bis(4-benzoyl-3-hydroxyphenoxy)-2-propyl methacrylate introduced into the antioxidant prepared by the present invention can efficiently neutralize free radicals through a hydrogen-donating mechanism, blocking the oxidative chain reaction and delaying the thermo-oxidative aging of the polymer matrix. The thioether bond introduced by trimethylolpropane tris(3-mercaptopropionic acid) consumes free radicals through self-oxidation, synergistically enhancing the antioxidant effect with the phenolic hydroxyl group. The introduced polyoxyethylene ether chain imparts good flexibility to the antioxidant and compatibility with the polymer matrix (such as polyamide-imide resin), preventing phase separation and ensuring uniform dispersion. The rigid structure of the benzene ring can enhance the antioxidant's thermal stability and reduce decomposition and volatilization at high temperatures. Furthermore, the three-arm structure increases the compound's molecular weight, reducing migration and volatilization at high temperatures. Furthermore, each arm has a long ether chain, which can improve the uniformity of the dispersion of the antioxidant functional groups.

[0043] The 1H,1H-perfluorooctadecane-1-ol used in Comparative Example 1 has a longer fluorocarbon chain, which enhances the rigidity of the perfluoroalkyl chain and strengthens the intermolecular van der Waals forces, allowing it to form a highly ordered crystalline structure. This crystallinity weakens the physical anchoring between the coating and the substrate, thereby reducing adhesion. Furthermore, the excessively long fluorocarbon chain restricts molecular motion, making it difficult to release internal stress through segmental motion, leading to brittle fracture during stretching.

[0044] In Comparative Example 2, when 2,6-dibromo-4-(trifluoromethoxy)aniline is replaced with p-bromoaniline, the amount of fluorine in the generated fluorine-containing compound is reduced, resulting in poor interfacial compatibility between the coating and the substrate (such as metal or polymer), making it difficult to form stable physical adsorption through hydrophobic effects or fluorine-fluorine interactions, resulting in decreased adhesion.

[0045] In Comparative Example 4, the alkyl chain becomes shorter and the surface energy increases, resulting in poor interfacial compatibility and decreased adhesion.

[0046] In Comparative Example 5, the long polyoxyethylene chains (containing multiple ethoxy repeating units) of allyloxy polyoxyethylene ether can form numerous intermolecular hydrogen bonds through ether bonds (-O-), strengthening the material's physical crosslinking network. However, diethylene glycol monovinyl ether contains only two ethoxy units, significantly reducing the hydrogen bond density and making free radical chain reactions more likely, resulting in poor antioxidant properties.

[0047] The four-arm structure of pentaerythritol tetrakis(3-mercaptopropionic acid) in Comparative Example 6 is too symmetrical and has a high density. The dispersion of effective antioxidant functional groups of equal weight is not as high as that in the examples.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. However, any equivalent changes, modifications and evolutions made by ordinary technicians in this field without departing from the scope of the technical solution of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. A high temperature resistant enameled wire insulation coating, characterized in that: The composition comprises the following raw materials in parts by weight: 40-50 parts of polyamide-imide resin, 20-30 parts of fluororesin, 5-10 parts of nano-silicon dioxide, 10-15 parts of silicon nitride, 5-8 parts of aluminum nitride, 300 parts of solvent, 0.5-1.5 parts of surfactant, 1-3 parts of modified tackifier, and 1-2.5 parts of antioxidant; The modified tackifier is prepared by the following method: S1: 2,6-dibromo-4-(trifluoromethoxy)aniline and 1H,1H-perfluoro-1-decanol react in the presence of potassium carbonate to form a two-arm fluorinated compound; S2: tribromoacetic acid and N-dodecyl imidazole react to form a cationic imidazole compound; S3: The dual-arm fluorinated compound and the cationic imidazole compound react under the action of EDC / NHS to form a modified tackifier.

2. The high temperature resistant enameled wire insulation coating according to claim 1, characterized in that: In step S1, the molar ratio of 2,6-dibromo-4-(trifluoromethoxy)aniline to 1H,1H-perfluoro-1-decanol is 1:(2-3).

3. The high temperature resistant enameled wire insulation coating according to claim 1, characterized in that: The molar ratio of tribromoacetic acid to N-dodecyl imidazole in step S2 is 1:(3-5).

4. The high temperature resistant enameled wire insulation coating according to claim 1, characterized in that: In step S3, the molar ratio of the double-arm fluorine-containing compound to the cationic imidazole compound is (1-1.5):

1.

5. The high temperature resistant enameled wire insulation coating according to claim 1, characterized in that: The solvent is one of 1,4-butyrolactone and propylene carbonate.

6. The high temperature resistant enameled wire insulation coating according to claim 1, characterized in that: The surfactant is one of stearic acid, oleic acid and lauric acid.

7. The high temperature resistant enameled wire insulation coating according to claim 1, characterized in that: The antioxidant is prepared by the following method: A1: Allyloxy polyoxyethylene ether and trimethylolpropane tris(3-mercaptopropionate) react under the action of initiator AIBN to form a three-arm thiol compound; A2: A three-arm thiol compound reacts with 1,3-bis(4-benzoyl-3-hydroxyphenoxy)-2-methylacrylate in the presence of catalyst C-94 and 1-butyl-3-methylimidazolium methanesulfonate ionic liquid to generate an antioxidant.

8. The high temperature resistant enameled wire insulation coating according to claim 7, characterized in that: In the step A1, the mass ratio of allyloxypolyoxyethylene ether to trimethylolpropane tris(3-mercaptopropionate) is 8:

1.

9. The high temperature resistant enameled wire insulation coating according to claim 7, characterized in that: In the step A2, the mass ratio of the three-arm thiol compound to 1,3-bis(4-benzoyl-3-hydroxyphenoxy)-2-propyl methylacrylate is 2.5:

1.

10. A method for preparing a high-temperature resistant enameled wire insulation coating according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Weigh by weight: 40-50 parts of polyamide-imide resin, 20-30 parts of fluororesin, 5-10 parts of nano-silicon dioxide, 10-15 parts of silicon nitride, 5-8 parts of aluminum nitride, 300 parts of solvent, 0.5-1.5 parts of surfactant, 1-3 parts of modified tackifier, and 1-2.5 parts of antioxidant; (2) Nano-silicon dioxide, silicon nitride, and aluminum nitride are mixed in proportion, a surfactant and 80 parts of solvent are added, and the mixture is dispersed by high-speed shearing to form a pre-treated filler; polyamide-imide resin is mixed with the remaining solvent, heated to 60-70°C, stirred and mixed, fluororesin is added, heated to 80-90°C, and stirred to form a homogeneous resin liquid; the pre-treated filler, modified tackifier, and antioxidant are added to the homogeneous resin liquid in sequence, sheared at high speed, and passed through a 400-mesh sieve to obtain a composite coating material; (3) The composite coating material is dipped onto the surface of the copper wire, and then pre-baked, initially cured, and cured to obtain a high-temperature resistant enameled wire insulation coating.

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