A high temperature resistant enameled wire insulating coating and a method for preparing the same

Abstract

The application discloses a high-temperature-resistant enameled wire insulating coating and a preparation method thereof, and relates to the technical field of insulating coatings. The high-temperature-resistant enameled wire insulating 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 high-temperature-resistant enameled wire insulating coating prepared by the application has good adhesion and oxidation resistance.

Description

TECHNICAL FIELD

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

[0002] As a key material for motors, electrical appliances, transformers and electronic devices, the performance of enameled wire is directly related to the reliability and service life of the equipment. The insulating paint layer is the core part of the enameled wire, which needs to have excellent insulating properties, high mechanical strength, heat resistance and adhesion to ensure long-term stable operation under various complex working conditions.

[0003] With the continuous development of modern industry and technology, the requirements for materials in high-temperature environments are increasingly stringent. Key equipment such as aerospace engines, electric vehicle motors, industrial motors and transformers must operate stably for a long time in high-temperature environments. Traditional insulating paint materials, such as polyester paint and polyurethane paint, perform well in low-temperature environments, but are prone to thermal degradation in high-temperature environments, resulting in a significant decrease in insulating properties, and may even cause safety hazards, making it difficult to meet these high-demand application scenarios. In addition to high-temperature environments, many industrial applications also require devices to cope with complex chemical corrosion environments, such as chemical plants, marine engineering and nuclear power plants, where devices may be exposed to corrosive substances such as acids, bases, solvents and salt spray. These substances can cause serious damage to traditional insulating paint, leading to insulation failure and affecting the safety and reliability of the equipment.

[0004] Chinese invention patent with publication number CN118600356A discloses a composite insulating coating for 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 properties and corrosion resistance, but its anti-aging performance is poor. SUMMARY

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

[0006] To achieve the above-mentioned purpose, the present application realizes the following technical solutions:

[0007] A high-temperature-resistant enameled wire insulating coating comprises the following raw materials by weight:

[0008] 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.

[0009] The modified tackifier is prepared by the following method:

[0010] S1: 2,6-dibromo-4-(trifluoromethoxy)aniline and 1H,1H-perfluoro-1-decanol react under the action of potassium carbonate to generate a double-arm fluorine-containing compound;

[0011] S2: tribromoacetic acid and N-dodecyl imidazole react to generate a cationic imidazole compound;

[0012] S3: the double-arm fluorine-containing compound and the cationic imidazole compound react under the action of EDC / NHS to generate a modified tackifier.

[0013] The molar ratio of 2,6-dibromo-4-(trifluoromethoxy)aniline and 1H,1H-perfluoro-1-decanol in the step S1 is 1:(2-3).

[0014] The molar ratio of tribromoacetic acid and N-dodecyl imidazole in the step S2 is 1:(3-5).

[0015] The molar ratio of the double-arm fluorine-containing compound and the cationic imidazole compound in the step S3 is (1-1.5):1.

[0016] The solvent is one of 1,4-butyrolactone and propylene carbonate.

[0017] The surfactant is one of stearic acid, oleic acid, and lauric acid.

[0018] The antioxidant is prepared by the following method:

[0019] A1: allyloxy polyoxyethylene ether and trimethylolpropane tris(3-mercaptopropionate) react under the action of initiator AIBN to generate a three-arm mercapto compound;

[0020] A2: the three-arm mercapto compound and 1,3-bis(4-benzoyl-3-hydroxyphenoxy)-2-methylpropyl acrylate react under the action of catalyst C-94, 1-butyl-3-methylimidazolium methane sulfonate ionic liquid to generate an antioxidant.

[0021] The mass ratio of allyloxy polyoxyethylene ether and trimethylolpropane tris(3-mercaptopropionate) in the step A1 is 8:1.

[0022] The mass ratio of the three-arm mercapto compound and 1,3-bis(4-benzoyl-3-hydroxyphenoxy)-2-methylpropyl acrylate in the step A2 is 2.5:1.

[0023] A preparation method of a high-temperature-resistant enameled wire insulating coating, comprising the following steps:

[0024] (1) Take by weight parts: polyamide-imide resin 40-50 parts, fluororesin 20-30 parts, nano-silicon dioxide 5-10 parts, silicon nitride 10-15 parts, aluminum nitride 5-8 parts, solvent 300 parts, surfactant 0.5-1.5 parts, modified tackifier 1-3 parts, antioxidant 1-2.5 parts;

[0025] (2) Mix nano-silicon dioxide, silicon nitride, and aluminum nitride in proportion, add surfactant and 80 parts of solvent, and disperse at high speed to form a pretreated filler; mix polyamide-imide resin with the remaining solvent, heat to 60-70℃, stir to dissolve, add fluororesin, heat to 80-90℃, and stir to form a homogeneous resin solution; add the pretreated filler, modified tackifier, and antioxidant to the homogeneous resin solution in turn, shear at high speed, and pass through a 400-mesh screen to obtain a composite coating material;

[0026] (3) Dip coat the composite coating material on the surface of the copper wire, then pre-bake, primary solidify, and solidify to obtain a high-temperature-resistant enameled wire insulating coating.

[0027] Due to the adoption of the above technical solutions, the beneficial effects of the present application include:

[0028] (1) The modified tackifier prepared by the present application realizes the balance of high adhesion and high tensile strength in the high-temperature-resistant enameled wire insulating coating through the synergistic effect of the rigidity enhancement of the fluorocarbon chain and the electrostatic adsorption of the cationic imidazole ring, and at the same time has excellent high-temperature stability and chemical durability, suitable for insulating protection requirements under severe working conditions.

[0029] (2) The antioxidant prepared by the present application realizes the triple anti-aging mechanism of free radical scavenging, ultraviolet shielding, and thermal stability enhancement through the multifunctional design of the chemical structure, and at the same time ensures long-term effectiveness by virtue of high molecular weight and topological structure, especially suitable for enameled wire insulating coating in high-temperature, strong UV radiation environment, significantly prolonging the service life of the coating. DETAILED DESCRIPTION

[0030] The present application will be further described below in conjunction with examples, but the present application is not limited to these examples.

[0031] Example 1 Preparation of modified tackifier:

[0032] S1: Under nitrogen protection, 500 ml of N,N-dimethylacetamide, 0.2 mol of 1H,1H-perfluoro-1-decanol, 50 g of anhydrous K2CO3 were added into a reactor, stirred and mixed, heated to 80°C, then 0.1 mol of 2,6-dibromo-4-(trifluoromethoxy) aniline was added in batches (0.05 mol per batch, 20 min interval between batches), reacted for 10 h, then cooled to room temperature, 100 ml of anhydrous ethanol and 600 ml of deionized water were added, stirred, precipitated, filtered, then washed with deionized water three times (100 ml of deionized water was used each time), then 300 ml of anhydrous ethanol was added for recrystallization, and vacuum dried at 70°C for 2 h to obtain a double-arm fluorine-containing compound; its reaction equation is shown as follows:

[0033]

[0034] S2: 400 ml of acetonitrile, 0.3 mol of N-dodecylimidazole were added into a reactor, stirred and mixed, heated to 50°C, then 0.1 mol of tribromoacetic acid was added, refluxed for 4 h, then distilled at 60°C under reduced pressure for 2 h, and vacuum dried at 60°C for 5 h to obtain a cationic imidazole compound; its reaction equation is shown as follows:

[0035]

[0036] S3: 1000 ml of DMF / DMSO (DMF:DMSO (V / V)=1:1) mixed solvent, 0.1 mol of cationic imidazole compound were added into a reactor, then 0.12 mol of EDC and 0.12 mol of NHS were added, stirred and activated at room temperature for 30 min, 0.1 mol of double-arm fluorine-containing compound was slowly added (0.05 mol per batch, 20 min interval between batches), reacted at room temperature for 8 h, then filtered, the filter cake was washed with 200 ml of saturated NaHCO3 solution three times, and vacuum dried at 60°C for 4 h to obtain a modified tackifier. Its reaction equation is shown as follows:

[0037]

[0038] Its nuclear magnetic resonance hydrogen spectrum data are as follows:

[0039] 1H 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, 0.8 Hz, 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).

[0040] Example 2 Preparation of modified tackifier:

[0041] S1: Under nitrogen protection, 500 ml of N,N-dimethylacetamide, 0.25 mol of 1H,1H-perfluoro-1-decanol, 50 g of anhydrous K2CO3 were added into the reactor, stirred and mixed uniformly, heated to 85°C, then 0.1 mol of 2,6-dibromo-4-(trifluoromethoxy) aniline was added in batches (0.05 mol per batch, 20 min interval between batches), reacted for 9 h, then cooled to room temperature, 100 ml of anhydrous ethanol and 600 ml of deionized water were added, stirred, precipitated, filtered, then washed with deionized water three times (100 ml of deionized water was used each time), then 300 ml of anhydrous ethanol was added for recrystallization, and vacuum dried at 70°C for 2 h to obtain a double-armed fluorine-containing compound;

[0042] S2: 400 ml of acetonitrile, 0.4 mol of N-dodecylimidazole were added into the reactor, stirred and mixed uniformly, heated to 60°C, then 0.1 mol of tribromoacetic acid was added, refluxed for 3 h, then distilled at 65°C under reduced pressure for 2 h, and vacuum dried at 60°C for 5 h to obtain a cationic imidazole compound;

[0043] S3: 1000 ml of DMF / DMSO (DMF:DMSO (V / V)=1:1) mixed solvent, 0.1 mol of cationic imidazole compound were added into the reactor, then 0.12 mol of EDC and 0.12 mol of NHS were added, stirred at room temperature for 50 min, 0.12 mol of double-armed fluorine-containing compound was slowly added (0.05 mol per batch, 20 min interval between batches), reacted at room temperature for 7 h, then filtered, the filter cake was washed with 200 ml of saturated NaHCO3 solution three times, and vacuum dried at 60°C for 4 h to obtain a modified tackifier.

[0044] Example 3 Preparation of modified tackifier:

[0045] S1: Under nitrogen protection, 500 ml of N,N-dimethylacetamide, 0.3 mol of 1H,1H-perfluoro-1-decanol, 50 g of anhydrous K2CO3 were added into a reactor, stirred and mixed, heated to 100°C, then 0.1 mol of 2,6-dibromo-4-(trifluoromethoxy) aniline was added in batches (0.05 mol per batch, 20 min interval between batches), reacted for 8 h, then cooled to room temperature, 100 ml of anhydrous ethanol and 600 ml of deionized water were added, stirred, precipitated, filtered, then washed with deionized water three times (100 ml of deionized water was used each time), then 300 ml of anhydrous ethanol was added for recrystallization, and vacuum dried at 70°C for 2 h to obtain a double-arm fluorine-containing compound;

[0046] S2: 400 ml of acetonitrile, 0.5 mol of N-dodecylimidazole were added into a reactor, stirred and mixed, heated to 70°C, then 0.1 mol of tribromoacetic acid was added, refluxed for 2 h, distilled at 60°C for 2.5 h under reduced pressure, and vacuum dried at 60°C for 5 h to obtain a cationic imidazole compound;

[0047] S3: 1000 ml of DMF / DMSO (DMF:DMSO (V / V)=1:1) mixed solvent, 0.1 mol of cationic imidazole compound were added into a reactor, then 0.12 mol of EDC and 0.12 mol of NHS were added, stirred and activated at room temperature for 60 min, 0.15 mol of double-arm fluorine-containing compound was slowly added (0.05 mol per batch, 20 min interval between batches), reacted at room temperature for 6 h, filtered, the filter cake was washed with 200 ml of saturated NaHCO3 solution three times, and vacuum dried at 60°C for 4 h to obtain a modified tackifier.

[0048] Example 4 Preparation of antioxidant:

[0049] A1: Under nitrogen protection, 500 g of DMSO, 10 g of trimethylolpropane tris(3- mercaptopropionate), 80 g of allyloxy polyoxyethylene ether (APEG-1000) were added into a reactor, stirred and mixed, heated to 80°C, then 10 g of initiator AIBN was added, reacted for 24 h, distilled at 60°C for 3 h under reduced pressure, and separated by a silica gel column to obtain a three-arm mercapto compound; its reaction equation is as follows:

[0050]

[0051] A2: Under nitrogen protection, 300 g of DMF, 50 g of a three-arm mercapto compound, 20 g of 1,3-bis(4-benzoyl-3-hydroxyphenoxy)-2-methyl propyl acrylate, 8 g of catalyst C-94, 3.5 g of 1-butyl-3-methyl imidazole methane sulfonate ionic liquid were sequentially added into a reactor, stirred and uniformly mixed, warmed to 100°C, reacted for 4 h, then cooled to room temperature, 400 g of deionized water was added and stirred uniformly, centrifuged and filtered, sequentially washed with 60 g of anhydrous ethanol, 60 g of deionized water, and vacuum dried at 50°C for 10 h to obtain an antioxidant. Its reaction equation is as follows:

[0052]

[0053] Example 5: Preparation of a high-temperature-resistant enameled wire insulation coating

[0054] (1) Take: polyamide-imide resin 400 g, fluororesin 200 g, nano-silicon dioxide 50 g, silicon nitride 100 g, aluminum nitride 50 g, solvent (1,4-butyrolactone) 3000 g, surfactant (stearic acid) 5 g, modified tackifier (prepared in Example 1) 10 g, antioxidant (prepared in Example 4) 10 g;

[0055] (2) Mix the nano-silicon dioxide, silicon nitride, and aluminum nitride in proportion, add the surfactant and 800 g of solvent, and disperse at a high speed of 3000 rpm for 45 min to form a pretreated filler; mix the polyamide-imide resin with the remaining solvent, warm to 60°C, and stir for 2 h until completely dissolved, then add the fluororesin, warm to 80°C, and stir for 40 min to form a homogeneous resin solution; sequentially add the pretreated filler, modified tackifier, and antioxidant to the homogeneous resin solution, high-speed shear (3000 rpm) for 1 h, pass through a 400-mesh screen to obtain a composite coating material;

[0056] (3) Dip the copper wire in the composite coating material at a speed of 3 m / min, with a wet film thickness of 120 μm; then pre-bake at 120°C for 20 min, primary cure at 220°C for 30 min, and cure at 320°C for 1 h to obtain a high-temperature-resistant enameled wire insulation coating.

[0057] Example 6: Preparation of a high-temperature-resistant enameled wire insulation coating

[0058] (1) Take: polyamide-imide resin 450 g, fluororesin 250 g, nano-silicon dioxide 80 g, silicon nitride 120 g, aluminum nitride 60 g, solvent (1,4-butyrolactone) 3000 g, surfactant (oleic acid) 10 g, modified tackifier (prepared in Example 2) 20 g, antioxidant (prepared in Example 4) 20 g;

[0059] (2) Mix nano-silica, silicon nitride, aluminum nitride in proportion, add surfactant and 800 g solvent, disperse at 3000 rpm for 40 min to form pretreated filler; mix polyamide-imide resin with the remaining solvent, heat to 65 °C, stir for 2 h until completely dissolved, add fluororesin, heat to 85 °C, stir for 30 min to form homogeneous resin solution; add pretreated filler, modified tackifier, antioxidant to the homogeneous resin solution in turn, high-speed shear (3000 rpm) for 1 h, pass through a 400 mesh screen to obtain a composite coating material;

[0060] (3) Dip copper wire in the composite coating material at a speed of 3 m / min, wet film thickness 100 μm; then pre-bake at 120 °C for 20 min, primary cure at 220 °C for 30 min, and cure at 320 °C for 1 h to obtain a high-temperature resistant enameled wire insulating coating.

[0061] Example 7 Preparation of a high-temperature resistant enameled wire insulating coating

[0062] (1) Take: polyamide-imide resin 500 g, fluororesin 300 g, nano-silica 100 g, silicon nitride 150 g, aluminum nitride 80 g, solvent (propylene carbonate) 3000 g, surfactant (lauric acid) 15 g, modified tackifier (prepared in Example 3) 30 g, antioxidant (prepared in Example 4) 25 g;

[0063] (2) Mix nano-silica, silicon nitride, aluminum nitride in proportion, add surfactant and 800 g solvent, disperse at 3000 rpm for 45 min to form pretreated filler; mix polyamide-imide resin with the remaining solvent, heat to 70 °C, stir for 2 h until completely dissolved, add fluororesin, heat to 90 °C, stir for 40 min to form homogeneous resin solution; add pretreated filler, modified tackifier, antioxidant to the homogeneous resin solution in turn, high-speed shear (3000 rpm) for 1 h, pass through a 400 mesh screen to obtain a composite coating material;

[0064] (3) Dip copper wire in the composite coating material at a speed of 3 m / min, wet film thickness 120 μm; then pre-bake at 120 °C for 20 min, primary cure at 220 °C for 30 min, and cure at 320 °C for 1 h to obtain a high-temperature resistant enameled wire insulating coating.

[0065] Comparative Example 1

[0066] The raw material composition and process of the high-temperature resistant enameled wire insulating coating are basically the same as those of Example 6, except that the modified tackifier is replaced with an equal weight of modified tackifier prepared by the following method:

[0067] The preparation method of the modified adhesion promoter of the present 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 with equal weight of 1H, 1H-perfluorooctadecan-1-ol.

[0068] Comparative Example 2

[0069] The raw material composition and process of the high-temperature-resistant enameled wire insulating coating are basically the same as those of Example 6, except that the modified adhesion promoter is replaced with equal weight of a modified adhesion promoter prepared by the following method:

[0070] The preparation method of the modified adhesion promoter of the present 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 with equal weight of p-bromoaniline.

[0071] Comparative Example 3

[0072] The raw material composition and process of the high-temperature-resistant enameled wire insulating coating are basically the same as those of Example 6, except that the modified adhesion promoter is replaced with equal weight of a modified adhesion promoter prepared by the following method:

[0073] The preparation method of the modified adhesion promoter of the present comparative example is basically the same as that of Example 2, except that the tribromoacetic acid added in step S2 is replaced with equal weight of 2,3-dibromosuccinic acid.

[0074] Comparative Example 4

[0075] The raw material composition and process of the high-temperature-resistant enameled wire insulating coating are basically the same as those of Example 6, except that the modified adhesion promoter is replaced with equal weight of a modified adhesion promoter prepared by the following method:

[0076] The preparation method of the modified adhesion promoter of the present comparative example is basically the same as that of Example 2, except that the N-dodecylimidazole added in step S2 is replaced with equal weight of N-butylimidazole.

[0077] Comparative Example 5

[0078] The raw material composition and process of the high-temperature-resistant enameled wire insulating coating are basically the same as those of Example 6, except that the antioxidant is replaced with equal weight of an antioxidant prepared by the following method:

[0079] The preparation method of the antioxidant of the present comparative example is basically the same as that of Example 4, except that the allyloxy polyoxyethylene ether added in step A1 is replaced with equal weight of diethylene glycol monovinyl ether.

[0080] Comparative Example 6

[0081] The raw material composition and process of the high-temperature resistant enameled wire insulating coating are basically the same as those of Example 6, except that the antioxidant is replaced with an equal weight of an antioxidant prepared by the following method:

[0082] The preparation method of the antioxidant of the present comparative example is basically the same as that of Example 4, except that the trimethylolpropane tris(3-mercaptopropionate) added in step A1 is replaced with an equal weight of pentaerythritol tetra(3-mercaptopropionate).

[0083] Comparative Example 7

[0084] The raw material composition and process of the high-temperature resistant enameled wire insulating coating are basically the same as those of Example 6, except that the antioxidant is replaced with an equal weight of an antioxidant prepared by the following method:

[0085] The preparation method of the antioxidant of the present comparative example is basically the same as that of Example 4, except that the 1,3-bis(4-benzoyl-3-hydroxyphenoxy)-2-methylpropyl acrylate added in step A2 is replaced with an equal weight of 2-hydroxy-4-(methacryloyloxy)benzophenone.

[0086] The polyamide-imide resin used in the examples and comparative examples of the present application has a model number of Torlon 4301 and is produced by Solvay Group; the fluororesin has a model number of F-208L and is produced by Daikin Fluorochemicals (China) Co., Ltd.; the nano-silicon dioxide has a model number of As-200 and is produced by Shenyang Chemical Co., Ltd.; the silicon nitride has a model number of XH-Si3N4-20 and is produced by Shanghai Xiaohuan Nanometer Technology Co., Ltd.; the aluminum nitride has a model number of XH-AlN-50 and is produced by Shanghai Xiaohuan Nanometer Technology Co., Ltd. The copper wire used in the present application is a hard round copper bare wire with a diameter of 3.00 mm.

[0087] The composite coating material / high-temperature resistant enameled wire insulating coating prepared in the examples and comparative examples of the present application was subjected to performance testing, and the test results are shown in Table 1.

[0088] The adhesion grade performance test was carried out according to GB / T 1720-2020, and the substrate was selected to be a copper plate with a size of 120 mm x 50 mm x 0.5 mm; the adhesion test of the insulating coating was carried out according to the peeling test method in GB / T 4074.3-2008 standard; the tensile strength was detected according to the standard GB / T 1040.1-2006, and the aging conditions were 150℃ and 95% humidity in an aging oven for 10 days; the volume resistivity was tested according to the standard GB / T 1410-2006, and the test voltage was 250V. The test results are shown in Table 1.

[0089] Table 1 Performance test table

[0090]

[0091] As can be seen from Table 1, the high-temperature-resistant enameled wire insulating coating prepared in the embodiments of the application has excellent adhesion, insulation performance and aging resistance.

[0092] The cationic imidazole group in the modified tackifier prepared in the application can be closely combined with the negative charge area on the surface of the copper wire through electrostatic attraction, thereby improving the adhesion of the coating to the substrate. The long carbon chain introduced by N-dodecyl imidazole increases the flexibility of the adhesive, making it more easily adapt to the micro-topography of the substrate surface, increasing the contact area and reducing the interface stress concentration. The high bond energy of the C-F bond endows the coating with excellent heat resistance and mechanical strength, and the rigid structure of the perfluoroalkyl chain can inhibit the slip of the molecular chain and enhance the tensile strength. The flexibility of the dodecyl chain and the rigidity of the fluorocarbon chain form a complement, which not only avoids brittle fracture, but also enhances the overall toughness through intermolecular forces (such as van der Waals forces).

[0093] The phenolic hydroxyl group in the antioxidant prepared in the application can efficiently neutralize free radicals through a hydrogen-donating mechanism, block the oxidation chain reaction, and delay the thermal-oxidative aging of the polymer matrix. The thioether bond introduced by trimethylolpropane tris(3-mercaptopropionate) can consume free radicals through its own oxidation, and cooperates with the phenolic hydroxyl group to enhance the antioxidant effect. The polyoxyethylene ether chain introduced endows the antioxidant with good flexibility and compatibility with the polymer matrix (such as polyamide-imide resin), avoids phase separation, and ensures uniform dispersion. The rigid structure of the benzene ring can improve the thermal stability of the antioxidant and reduce decomposition and volatilization at high temperatures. In addition, the three-arm structure increases the molecular weight of the compound, reduces migration and volatilization at high temperatures, and each arm has a long-chain ether chain, which can improve the uniformity of the dispersion of antioxidant functional groups.

[0094] The 1H,1H-perfluorooctadecan-1-ol used in Comparative Example 1 has a longer fluorocarbon chain, the rigidity of the perfluoroalkyl chain is enhanced, and the intermolecular van der Waals force is stronger, which is easy to form a highly ordered crystalline structure. This crystallinity can weaken the physical anchoring effect of the coating to the substrate, thereby reducing the adhesion. At the same time, the long fluorocarbon chain leads to restricted molecular motion, and the internal stress of the material is difficult to release through chain segment motion, resulting in brittle fracture during stretching.

[0095] In Comparative Example 2, when 2,6-dibromo-4-(trifluoromethoxy) aniline is replaced by p-bromoaniline, the amount of fluorine in the generated fluorine-containing compound is reduced, resulting in poor interfacial compatibility of the coating with the substrate (such as metal or polymer), and it is difficult to form stable physical adsorption through hydrophobic interaction or fluorine-fluorine interaction, resulting in a decrease in adhesion.

[0096] In Comparative Example 4, the alkyl chain is shortened, the surface energy is increased, resulting in poor interfacial compatibility and a decrease in adhesion.

[0097] The long polyoxyethylene chain (containing multiple ethoxy repeating units) of the allyloxy polyoxyethylene ether in Comparative Example 5 can form a large number of intermolecular hydrogen bonds through ether bonds (-O-), enhancing the physical crosslinking network of the material. The diethylene glycol monovinyl ether contains only two ethoxy units, and the hydrogen bond density is significantly reduced, so the free radical chain reaction is more likely to occur, and the antioxidant performance is poor.

[0098] The four-arm structure of tetra (3-mercaptopropionic acid) pentaerythritol ester in Comparative Example 6 is too symmetrical, and the density is too large, so the effective antioxidant functional group dispersity is not as high as that of the embodiment under the same weight.

[0099] The above is only a preferred embodiment of the present application and is not intended to limit the present application; however, for those of ordinary skill in the art, some minor changes, modifications, and equivalent variations of the above disclosed technical content can be made without departing from the scope of the technical solutions of the present application, and all such equivalent embodiments are within the scope of the present application; at the same time, any equivalent changes, modifications, and variations of the above embodiments according to the essential technology of the present application are still within the protection scope of the technical solutions of the present application.

Claims

1. A high-temperature resistant enameled wire insulation coating, characterized in that, The ingredients include the following parts by weight: 40-50 parts polyamide-imide resin, 20-30 parts fluororesin, 5-10 parts nano silica, 10-15 parts silicon nitride, 5-8 parts aluminum nitride, 300 parts solvent, 0.5-1.5 parts surfactant, 1-3 parts modified tackifier, and 1-2.5 parts antioxidant; The modified thickener is prepared by the following method: S1: 2,6-Dibromo-4-(trifluoromethoxy)aniline and 1H,1H-perfluoro-1-decyl alcohol react in the presence of potassium carbonate to form a two-armed fluorine-containing compound. S2: Tribromoacetic acid and N-dodecylimidazole react to form a cationic imidazole compound; S3: A modified tackifier is generated by the reaction of a two-arm fluorinated compound and a cationic imidazole compound under the action of EDC / NHS.

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 and 1H,1H-perfluoro-1-decyl alcohol is 1:(2-3).

3. The high-temperature resistant enameled wire insulation coating according to claim 1, characterized in that, In step S2, the molar ratio of tribromoacetic acid and N-dodecyl imidazole 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 two-arm fluorinated compound and 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-mercaptopropionic acid) ester react under the action of initiator AIBN to generate a three-armed thiol compound; A2: A three-armed thiol compound reacts with 1,3-bis(4-benzoyl-3-hydroxyphenoxy)-2-methacrylate propyl ester 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 step A1, the mass ratio of allyloxy polyoxyethylene ether to trimethylolpropane tris(3-mercaptopropionic acid) ester is 8:

1.

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

1.

10. A method for preparing a high-temperature resistant enameled wire insulation coating according to any one of claims 1-9, characterized in that, Includes the following steps: (1) Weigh out the following by weight: 40-50 parts of polyamide-imide resin, 20-30 parts of fluororesin, 5-10 parts of nano-silica, 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) Mix nano-silica, silicon nitride, and aluminum nitride in proportion, add surfactant and 80 parts solvent, and disperse by high-speed shearing to form a pretreated filler; mix polyamide-imide resin with the remaining solvent, heat to 60-70℃, stir and mix, add fluororesin, heat to 80-90℃, and stir to form a homogeneous resin liquid; add the pretreated filler, modified tackifier, and antioxidant to the homogeneous resin liquid in sequence, shear by high speed, and pass 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, pre-cured and cured to obtain a high-temperature resistant enameled wire insulation coating.

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