A rare earth modified abrasion-resistant enameled wire insulating coating and a preparation method thereof

Abstract

This invention relates to the field of electrical insulation materials and special polymer coatings, specifically to a rare earth-modified wear-resistant enameled wire insulation coating and its preparation method; it comprises an insulating resin base, a rare earth-organic hybrid modifier, and an organic solvent; the coating uses a complex sol formed by the coordination of polysiloxane containing multidentate chelate ligands and reactive end groups with rare earth ions as the modifier; its core is to utilize the multidentate chelate ligands to covalently connect the polysiloxane skeleton and to firmly bind rare earth ions through coordination bonds, thereby constructing a stable and uniform molecular-level dispersed network structure; this invention abandons the traditional inorganic particle physical blending method, effectively suppressing the kinetic mismatch and gravity sedimentation defects caused by high-density rare earth phases, so that the liquid coating maintains excellent compatibility and uniformity during long-term storage.

Description

Technical Field

[0001] This invention relates to the field of electrical insulation materials and special polymer coatings, specifically to a rare earth-modified wear-resistant enameled wire insulation coating and its preparation method. Background Technology

[0002] In the current operating environment of high-voltage alternating electric fields and extreme mechanical stress, the insulation coating of enameled wire is prone to thermal degradation and mechanical wear, leading to inter-turn short circuit defects. To improve the wear resistance and thermo-oxidative aging resistance of the enameled wire insulation coating, existing solutions generally adopt a physical blending modification approach, which involves directly adding nano-inorganic particles to the insulating resin varnish for dispersion and grinding. Although this approach provides a certain level of insulation protection under normal operating conditions, the physical blending of high-density inorganic particles is prone to uneven dispersion and agglomeration, causing the liquid coating to easily undergo gravity sedimentation and severe phase separation during long-term storage. At the same time, the agglomeration of inorganic particles introduces a large number of microscopic defects into the varnish film, resulting in severe embrittlement of the coating and a significant reduction in breakdown voltage at both room temperature and high temperature, making it difficult to meet the stringent requirements of enameled wire for mechanical wear resistance and insulation breakdown strength under extreme operating conditions.

[0003] Therefore, how to overcome the compatibility and sedimentation limitations caused by conventional inorganic particle physical blending, and construct a stable and uniform cross-linked network in situ in the resin matrix to simultaneously enhance the self-lubricating wear resistance and thermo-oxidative aging resistance of the enameled wire insulation coating, has become an urgent technical problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a rare-earth modified wear-resistant enameled wire insulation coating and its preparation method, so as to solve the problems mentioned in the background art. Specifically, the technical solution of this invention is as follows: A rare earth-modified wear-resistant enameled wire insulation coating, comprising: Insulating resin base material, rare earth-organic hybrid modifier and organic solvent; The insulating resin base material is 100 parts by weight, and the rare earth-organic hybrid modifier is 1 to 5 parts by weight. The rare earth-organic hybrid modifier is a complex sol formed by coordination of a polysiloxane containing a multidentate chelating ligand and reactive end groups with rare earth ions; the multidentate chelating ligand is covalently linked to the polysiloxane backbone, and the rare earth ions are coordinated to the multidentate chelating ligand.

[0005] Furthermore, the insulating resin base material is selected from one or more of polyamide-imide resin, polyimide resin, or polyester-imide resin.

[0006] Furthermore, the rare earth ion is selected from Ce3+, Ce4+ or Y3+; the multidentate chelating ligand is a group containing a Schiff base structure; the reactive end group is a silanol group, an alkoxysilyl group or a residual amino group; and the polysiloxane backbone contains Si-O-Si segments.

[0007] A method for preparing a rare earth-modified wear-resistant enameled wire insulation coating includes: An aminosilane coupling agent and a polydentate ligand compound containing a carbonyl group were added to an anhydrous alcohol solvent, a dehydrating agent was added, and the reaction was refluxed under heating conditions. The dehydrating agent was removed by filtration to obtain a silane precursor solution containing a Schiff base structure. Soluble rare earth salts are dissolved in a polar aprotic solvent and slowly added dropwise to the silane precursor solution containing Schiff base structure. The reaction is stirred at a constant temperature to allow the Schiff base structure to coordinate with rare earth ions, thereby obtaining a rare earth coordinated silane complex solution. Deionized water and an acidic catalyst were added to the rare earth coordinated silane complex solution, and the pH of the system was adjusted to 3-5. A hydrolysis-condensation reaction was carried out at a constant temperature to form a rare earth-polysiloxane sol intermediate. Subsequently, anhydrous alcohol solvents and small molecule alcohols generated in the reaction were removed from the system by vacuum distillation, and a polar aprotic solvent was added for solvent replacement. The solid content was adjusted to 10%-30% to obtain a rare earth-organic hybrid modifier. The rare earth-organic hybrid modifier is added to a polar solvent solution of an insulating resin base with a solid content of 20% to 40% according to the solid content ratio, and the mixture is stirred at high speed at room temperature to disperse it evenly, thereby obtaining the rare earth modified wear-resistant enameled wire insulation coating. The molar ratio of the aminosilane coupling agent to the carbonyl-containing polydentate ligand compound is 1:1; the molar ratio of the carbonyl-containing polydentate ligand compound to the rare earth ions is 3:1 to 4:1.

[0008] Furthermore, the aminosilane coupling agent is 3-aminopropyltriethoxysilane, the carbonyl-containing polydentate ligand compound is salicylaldehyde, the anhydrous alcohol solvent is anhydrous ethanol, and the dehydrating agent is anhydrous magnesium sulfate.

[0009] Furthermore, the soluble rare earth salt is cerium acetate hydrate or cerium nitrate hexahydrate; the polar aprotic solvent is N-methylpyrrolidone or N,N-dimethylformamide.

[0010] Furthermore, the reflux reaction under heating conditions takes 4 hours; the stirring reaction under constant temperature conditions takes 50℃~80℃ for 6 hours.

[0011] Furthermore, the acidic catalyst is glacial acetic acid; the amount of deionized water is 0.5 to 1.5 times the molar number of alkoxy groups in the aminosilane coupling agent.

[0012] Furthermore, the hydrolysis-condensation reaction is carried out at a constant temperature of 40℃ to 60℃ for 4 hours; the vacuum distillation is carried out at a temperature of 60℃.

[0013] Furthermore, the high-speed stirring and dispersion at room temperature is carried out at a speed of 1500 r / min for 30 min.

[0014] Compared with the prior art, the present invention has the following improvements and advantages: 1. This invention addresses the shortcomings of existing inorganic particle physical blending techniques, which easily leads to uneven dispersion and agglomeration, resulting in gravity sedimentation and severe phase separation in liquid coatings. This solution precisely introduces a rare earth-organic hybrid modifier into the insulating resin base. This modifier utilizes multidentate chelating ligands to firmly connect to the polysiloxane backbone via covalent bonds, and stably binds rare earth ions through coordination bonds, thereby forming a stable and uniform complex sol. This complex sol formed by the coordination of polysiloxane and rare earth ions effectively suppresses the physical sedimentation of the high-density rare earth phase. Verification by examples shows that the liquid coating maintains excellent compatibility and uniformity even during storage for several months, avoiding stratification problems. 2. This invention addresses the technical challenge of thermal degradation and mechanical wear of enameled wire insulation coatings under extreme mechanical stress. The rare-earth-organic hybrid modifier in this invention plays a crucial role based on a polysiloxane framework containing Si-O-Si segments. The polysiloxane component, containing multidentate chelating ligands and reactive end groups, can migrate and accumulate on the coating surface, imparting excellent self-lubricating properties to the coating film. Simultaneously, the structure formed by the complexation of the multidentate chelating ligands and rare-earth ions constructs a robust network within the resin, effectively dissipating externally applied mechanical stress. Example tests confirm that this technology significantly reduces the dynamic friction coefficient of the enameled wire surface and significantly increases the number of wear cycles in reciprocating wear tests without sacrificing the cylindrical wrapping flexibility of the coating film. 3. In the background technology of this invention, the aggregation of traditional inorganic particles introduces a large number of defects into the interior of the enamel film, resulting in severe embrittlement of the insulation layer and a significant drop in breakdown voltage. The rare earth-organic hybrid modifier of this invention contains reactive end groups such as silanol, alkoxysilyl, or residual amino groups, which can chemically bond with insulating resin matrix materials selected from polyamide-imide resin, polyimide resin, or polyester-imide resin to form a dense structure. The rare earth ions, such as Ce3+, Ce4+, or Y3+, uniformly distributed in the network effectively inhibit the thermo-oxidative degradation of polymer chains under high-temperature alternating electric fields and weaken local electric field distortion. This not only avoids the microcrack defects caused by traditional physical blending, but also significantly improves the high-temperature insulation breakdown voltage threshold of the enameled wire, while controlling the thermo-oxidative aging weight loss rate at an extremely low level, fundamentally reducing the risk of inter-turn short circuits. Attached Figure Description

[0015] Figure 1 This is a flowchart of a method for preparing a rare earth-modified wear-resistant enameled wire insulation coating. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0017] Example 1: A rare earth-modified wear-resistant enameled wire insulation coating, comprising: The mixture comprises an insulating resin base, a rare earth-organic hybrid modifier, and an organic solvent; by weight, the insulating resin base comprises 100 parts by solid content, and the rare earth-organic hybrid modifier comprises 1 part by solid content; the rare earth-organic hybrid modifier is a complex sol formed by coordination of a polysiloxane containing a multidentate chelating ligand and a reactive end group with rare earth ions; the multidentate chelating ligand is covalently linked to the polysiloxane backbone, and the rare earth ions are coordinated to the multidentate chelating ligand.

[0018] This embodiment provides a rare earth-modified wear-resistant enameled wire insulation coating, which aims to overcome the defects of inter-turn short circuit caused by thermal degradation and mechanical wear of enameled wire insulation coating under extreme working conditions. By precisely introducing 1 part of rare earth-organic hybrid modifier with solid content, a molecularly dispersed rare earth crosslinking network is constructed in situ in the insulating resin matrix. The rare earth-organic hybrid modifier overcomes the limitation that conventional inorganic particle physical blending is prone to sedimentation and phase separation. It uses multidentate chelating ligands to firmly anchor rare earth ions on the polysiloxane backbone to form a stable and uniform complex sol. Specifically, the multidentate chelating ligand is directly connected to the silicon atoms of the polysiloxane backbone via carbon-silicon covalent bonds through its end carbon chain groups; rare earth ions, as central atoms, form coordinate bonds with nitrogen, oxygen and other heteroatoms in the multidentate chelating ligand, with coordination numbers typically ranging from 6 to 8, thus clarifying the spatial stereoconfiguration of the complex. The design of this specific structure not only effectively suppresses the gravitational settling of high-density rare earth phases, ensuring the compatibility of liquid coatings during long-term storage, but also, during the subsequent curing and film-forming stage, driven by the cross-linking curing temperature gradient of 350℃ to 450℃, it promotes the spontaneous migration and enrichment of flexible polysiloxane segments to the coating surface, giving the paint film good self-lubricating properties, and forming tough organic-inorganic interpenetrating network nodes with rare earth ions, thereby achieving simultaneous enhancement of wear resistance and resistance to thermo-oxidative aging.

[0019] Example 2: The insulating resin base material is selected from polyamide-imide resin.

[0020] In this embodiment, polyamide-imide resin is selected as the insulating resin base material. This is intended to leverage the high heat resistance of the imide rings in its main chain and the excellent adhesion of the amide bonds to provide a solid electrical insulation foundation for enameled wires under high-voltage alternating electric fields. This resin system can covalently bond with the reactive end groups surrounding the rare-earth-organic hybrid modifier during the high-temperature baking stage, forming a dense cascaded cross-linked network that effectively resists the intrusion of external mechanical stress. The rare-earth ions are selected from Ce3+; the multidentate chelating ligands are groups containing Schiff base structures; the reactive end groups are silanol groups; and the polysiloxane backbone contains Si-O-Si segments. The selected Ce3+ ions, with their excellent antioxidant properties, effectively capture and eliminate thermo-oxidative free radicals inside the coating, effectively inhibiting the thermo-oxidative degradation of polymer chains under high-temperature alternating electric fields; the multidentate chelating ligand containing Schiff base structure, relying on its stable coordination binding ability, firmly locks Ce3+ ions within the polysiloxane network. Specifically, the imine (-C=N-) nitrogen atom in this Schiff base structure, together with the adjacent oxygen-containing group, acts as an electron donor, forming a stable six-membered chelate ring coordination bond with the empty orbital of the central Ce3+ ion. Each Ce3+ ion typically binds to 3 to 4 such bidentate Schiff base ligands, achieving a coordination number of 6 to 8, forming an octahedral or higher coordination polyhedral spatial configuration, thereby blocking the phase separation tendency under the action of gravity. The silanol group, as a reactive end group, ensures the chemical compatibility of the interface between the modifier and the insulating resin matrix, while the introduction of flexible Si-O-Si segments effectively dissipates external mechanical stress, offsets the internal brittle defects caused by high crosslinking density, and maintains the flexibility required for enameled wire processing.

[0021] Example 3: A method for preparing a rare earth-modified wear-resistant enameled wire insulation coating includes: An aminosilane coupling agent and a polydentate ligand compound containing a carbonyl group were added to an anhydrous alcohol solvent. A dehydrating agent was added, and the mixture was refluxed under heating conditions. The dehydrating agent was removed by filtration to obtain a silane precursor solution containing a Schiff base structure. A soluble rare earth salt was dissolved in a polar aprotic solvent and slowly added dropwise to the silane precursor solution containing a Schiff base structure. The mixture was stirred at a constant temperature to allow the Schiff base structure to coordinate with the rare earth ions, resulting in a rare earth coordinated silane complex solution. Deionized water and an acidic catalyst were added to a solution of rare earth coordinated silane complexes, and the pH of the system was adjusted to 3-5. A hydrolysis-condensation reaction was carried out at a constant temperature to form a rare earth-polysiloxane sol intermediate. Subsequently, anhydrous alcohol solvents and small molecule alcohols generated in the reaction were removed from the system by vacuum distillation, and a polar aprotic solvent was added for solvent replacement. The solid content was adjusted to 10%-30% to obtain a rare earth-organic hybrid modifier. Rare earth-organic hybrid modifier is added to a polar solvent solution of insulating resin base with a solid content of 20% to 40% according to the solid content ratio, and the mixture is stirred at high speed at room temperature to disperse it evenly, so as to obtain rare earth modified wear-resistant enameled wire insulation coating. The molar ratio of the aminosilane coupling agent to the carbonyl-containing polydentate ligand compound is 1:1; the molar ratio of the carbonyl-containing polydentate ligand compound to the rare earth ions is 3:1 to 4:1.

[0022] Anhydrous alcohol solvents and small molecule alcohols generated in the reaction were removed from the system by vacuum distillation. The remaining total mass of the system was weighed, and a sample was taken to determine the current solid content. A 2g sample was placed in an oven and baked at 150℃ for 1 hour. The mass ratio before and after baking was measured to calculate the effective polymer mass. Then, polar aprotic solvent was added quantitatively for solvent replacement. The solid content was adjusted using the following formula. Up to 10% in, Solid content; Effective polymer mass, unit: g; The total mass of the polar aprotic solvent added to the system and the solvent in the residual system is expressed in g. A rare earth-organic hybrid modifier is obtained. The rare earth-organic hybrid modifier is added to a polar solvent solution of an insulating resin base with a solid content of 20% according to the solid content ratio. The solution is dispersed uniformly by high-speed stirring at room temperature to obtain a rare earth-modified wear-resistant enameled wire insulation coating. The molar ratio of the aminosilane coupling agent to the carbonyl-containing polydentate ligand compound is 1:1; the molar ratio of the carbonyl-containing polydentate ligand compound to rare earth ions is 3:1. The aminosilane coupling agent is 3-aminopropyltriethoxysilane, the carbonyl-containing polydentate ligand compound is salicylaldehyde; the anhydrous alcohol solvent is anhydrous ethanol; the dehydrating agent is anhydrous magnesium sulfate; the soluble rare earth salt is cerium acetate hydrate; the polar aprotic solvent is N-methylpyrrolidone; the reflux reaction time under heating conditions is 4 h; the stirring reaction temperature at constant temperature is 50 °C and the time is 6 h. The acid catalyst is glacial acetic acid; the amount of deionized water is 0.5 times the number of moles of alkoxy groups in the aminosilane coupling agent; the hydrolysis and polycondensation reaction is carried out at a constant temperature of 40℃ for 4 hours; the vacuum distillation temperature is 60℃; the high-speed stirring and dispersion at room temperature is 1500 r / min for 30 minutes. This embodiment establishes the basic synthesis mechanism and complete process flow of rare earth modified wear-resistant enameled wire insulation coating; 3-aminopropyltriethoxysilane and salicylaldehyde are placed in anhydrous ethanol at a stoichiometric ratio of 1:1, and anhydrous magnesium sulfate is used as a dehydrating agent to heat and reflux for 4 hours. The aim is to eliminate the reaction in situ through nucleophilic addition to construct a Schiff base structure. The continuous presence of the dehydrating agent breaks the thermodynamic equilibrium of the reaction and promotes the maximization of conversion rate. In the in-situ coordination complexation stage, cerium acetate hydrate dissolved in N-methylpyrrolidone was slowly added dropwise, and the molar ratio of the polydentate ligand compound containing carbonyl groups to rare earth ions was controlled at 3:1. The mixture was stirred at a constant temperature of 50°C for 6 hours. The temperature condition of 50°C was set to provide the basic reaction activation energy while avoiding excessive solvent evaporation, so that the nitrogen and oxygen atoms in the Schiff base structure could form a stable coordination field with Ce3+ ions. Specifically, in the Schiff base ligand formed by the condensation of the amino group of 3-aminopropyltriethoxysilane and the aldehyde group of salicylaldehyde, the imine nitrogen atom and the deprotonated phenolic hydroxyl oxygen atom on the salicylaldehyde benzene ring jointly participate in the bidentate coordination of Ce3+ ions, forming a stable six-membered chelate ring; at the same time, the propyl chain at the silane end is covalently connected to the silicon atoms of the polysiloxane backbone through carbon-silicon single bonds, thereby precisely defining the specific spatial connection structure between the multidentate chelate ligand, the polysiloxane backbone, and rare earth ions in the rare earth-organic hybrid modifier. Based on this, 0.5 times the molar amount of alkoxy groups of deionized water and glacial acetic acid were introduced to precisely adjust the pH of the system to 3, and a partial hydrolysis-condensation reaction was induced at 40°C for 4 hours. The low water content and mild conditions of 40°C in this stage effectively suppressed the kinetic over-crosslinking of siloxanes, prevented the system from crossing the critical threshold and undergoing macroscopic gelation, and constructed a hyperbranched nanoscale rare earth-polysiloxane sol. After hydrolysis and polycondensation, a 60°C vacuum distillation process was initiated to forcibly remove low-boiling-point alcohols, and N-methylpyrrolidone was used for solvent replacement to maintain a solid content of 10%. This removed residual proton solvents from the system, eliminating the adverse effects of solvent residues on compatibility with the insulating resin matrix. Finally, the rare earth-organic hybrid modifier was introduced into an insulating resin matrix with a solid content of 20%, and dispersed continuously for 30 minutes using a high-speed shear force field of 1500 r / min, achieving a uniform distribution of the nano-dispersed phase in the continuous polymer phase. This embodiment verifies that an insulating coating system with basic self-lubricating and anti-aging properties can still be successfully constructed under lower limit parameter conditions, demonstrating the intrinsic feasibility of the process route.

[0023] Example 4: A rare-earth modified wear-resistant enameled wire insulation coating and its preparation method are disclosed. By weight, the rare-earth-organic hybrid modifier comprises 3 parts (based on solid content); the molar ratio of the carbonyl-containing polydentate ligand compound to rare-earth ions is 3.5:1; the stirring reaction temperature is 65℃; the pH of the system is adjusted to 4; the amount of deionized water is 1.0 times the molar number of alkoxy groups in the aminosilane coupling agent; the hydrolysis-condensation reaction temperature is 50℃; the solid content is adjusted to 20%; and the solid content of the insulating resin base is 30%. In this embodiment, polyimide resin is selected as the insulating resin base material, 3-aminopropyltrimethoxysilane is selected as the aminosilane coupling agent, 2-hydroxyacetophenone is selected as the carbonyl-containing polydentate ligand compound, cerium sulfate is selected as the soluble rare earth salt to provide Ce4+ ions, and the reflux reaction time under heating conditions is adjusted to 5h, the vacuum distillation temperature is adjusted to 70℃, and the high-speed stirring and dispersion at room temperature is set to 1200r / min for 40min. This embodiment further optimizes the core synthesis parameters by adjusting the amount of rare earth-organic hybrid modifier to 3 parts, achieving a balance between improving the wear resistance of the coating and maintaining the flexibility of the original insulating resin base, thus avoiding the risk of embrittlement of the paint film due to excessive crosslinking density; the in-situ coordination complexation temperature of 65°C effectively overcomes the defect of slow reaction kinetics at low temperatures, ensuring that the Schiff base structure and rare earth ions achieve full chelation. A 1.0 times water volume for hydrolysis, combined with a weakly acidic environment at pH 4, precisely controlled the appropriate polycondensation process of the siloxane. This ensured that the molecular weight of the polysiloxane backbone met the requirements for forming a continuous low surface energy lubricating layer, while maintaining the thermodynamic stability of the nanoscale sol system. The introduction of polyimide resin further enhanced the intrinsic heat resistance of the matrix, while the replaced coupling agent and ligands could also efficiently construct Schiff base structures and stably complex with rare earth ions. The adjusted reflux time, distillation temperature, and stirring parameters demonstrated the wide range of process windows. This parameter combination represents typical operating conditions in conventional industrial continuous coating production, verifying the excellent robustness and comprehensive electromechanical performance of this technical solution within a moderate parameter range.

[0024] Example 5: A rare-earth modified wear-resistant enameled wire insulation coating and its preparation method are disclosed. By weight, the rare-earth-organic hybrid modifier comprises 5 parts (solid content); the molar ratio of the carbonyl-containing polydentate ligand compound to rare-earth ions is 4:1; the stirring reaction temperature is 80℃; the pH of the system is adjusted to 5; the amount of deionized water is 1.5 times the molar number of alkoxy groups in the aminosilane coupling agent; the hydrolysis-condensation reaction temperature is 60℃; the solid content is adjusted to 30%; and the solid content of the insulating resin base is 40%. In this embodiment, the insulating resin base material is selected as polyesterimide resin, the aminosilane coupling agent is selected as N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and the carbonyl-containing polydentate ligand compound is selected as acetylacetone. In addition, the reflux reaction time under heating conditions is shortened to 3h, the temperature of vacuum distillation is reduced to 50℃, the speed of high-speed stirring and uniform dispersion at room temperature is increased to 1800r / min, and the time is shortened to 20min. The addition of rare earth-organic hybrid modifier was increased to 5 parts, and combined with a high ligand metal molar ratio of 4:1 and a complexation temperature of 80°C, aiming to construct an extremely high-density inorganic-organic hybrid cross-linking network inside the insulating resin matrix; the addition of 1.5 times the amount of deionized water and the hydrolysis condensation temperature of 60°C accelerated the deep evolution of the siloxane network, so that the coating has excellent surface hardness and scratch resistance after high temperature curing. Polyesterimide resin imparts superior flexibility and adhesion to the coating; different combinations of silane precursors and ligands can still form stable rare earth-polysiloxane sols with shortened reflux time and lower distillation temperature; high-speed, short-time stirring process effectively addresses the increase in viscosity of high solid content systems, ensuring uniform distribution of the nano-dispersed phase. This embodiment is particularly suitable for coating scenarios of flat wire motor windings in new energy vehicles where there are extreme requirements for wear resistance. Although the high crosslinking density consumes the free volume of polymer chain segments to some extent, the coating film can still meet the basic cylindrical wrapping flexibility test due to the internal plasticizing effect of the polysiloxane flexible chain segments, demonstrating the structural stability of the material system under extreme formulations.

[0025] Comparative Example 1: This comparative example includes three comparative samples; among them, comparative example 1-1 uses commercially available polyamide-imide insulating varnish with a solid content of 30% as a comparative sample. No rare earth-organic hybrid modifiers or other inorganic fillers are added during the preparation and coating process. The enameled wire is coated and baked at high temperature to form a film directly according to the standard process, which is used to establish the baseline of basic mechanical and electrical properties of the unmodified insulating resin base material. Comparative Examples 1-2 used the same raw materials and preparation process as Example 2, the only difference being that the amount of rare earth-organic hybrid modifier added was reduced to 0.5 parts, which is lower than the protection limit of 1 part; Comparative Examples 1-3 used the same raw materials and preparation process as Example 2, the only difference being that the amount of rare earth-organic hybrid modifier added was increased to 6 parts, which is higher than the protection limit of 5 parts.

[0026] Comparative Example 2: 9g of nano-cerium oxide powder with an average particle size of 50nm was directly added to 1000g of commercially available polyamide-imide insulating varnish with a solid content of 30%; the mixture was then ultrasonically dispersed and ground in a sand mill for 2 hours to prepare a physically blended insulating coating.

[0027] Verification test To comprehensively evaluate the overall service capability of the rare earth-modified wear-resistant enameled wire insulation coating provided by this invention under extreme working conditions, this verification test was established. The test focuses on examining the liquid storage stability of the coating system, as well as the surface friction characteristics, mechanical wear resistance, flexibility, insulation breakdown strength, and resistance to thermo-oxidative aging of the enameled wire after curing. This is to verify the synergistic enhancement effect of the rare earth-organic hybrid modifier in the polymer network.

[0028] Test Standards In this test, the appearance and dimensions of the enameled wire were measured in accordance with GB / T4074.1; the mechanical properties, including the static friction coefficient and unidirectional scraping force, were performed in accordance with GB / T4074.3; the electrical properties, including the breakdown voltage at room temperature and high temperature, were performed in accordance with GB / T4074.5; and the thermal properties, including the weight loss rate due to thermo-oxidative aging, were performed in accordance with the relevant thermal aging assessment procedures in GB / T4074.6.

[0029] Specific testing process The insulating coatings prepared in Examples 1 to 5 and Comparative Examples 1 to 2 were uniformly coated onto oxygen-free bare copper wires with a diameter of 1.0 mm using a standard vertical enameled wire coating machine. The coating process was set to 6 passes, and the temperature gradient of the baking oven was controlled between 350°C and 450°C to ensure that the solvent was fully evaporated and the resin was deeply cross-linked. Finally, the thickness of the coating film on one side was kept constant at 40 μm. After the sample preparation was completed, the liquid coating was placed at room temperature and its stratification and sedimentation were observed. The surface smoothness of the wire was determined using a dynamic friction coefficient tester; the number of friction cycles at which the insulation layer was damaged was recorded using a reciprocating paint scraping tester under a fixed load; the flexibility was evaluated by observing whether the paint film cracked through a 1-day cylindrical wrapping test; a withstand voltage tester was used to apply a stepped electric field at 25℃ and 200℃ until the insulation broke down; a fixed length of wire was placed in a 200℃ high-temperature aging chamber for 1000 hours, and the weight difference before and after aging was measured to calculate the weight loss rate.

[0030] Experimental data show that Examples 1 to 5 of this invention significantly surpass the prior art in all core indicators. From the median parameters of Example 2, its reciprocating wear resistance reached 850 cycles, a 240% increase compared to Comparative Example 1-1, and the surface dynamic friction coefficient decreased to 0.08. This confirms the thermodynamic mechanism by which the flexible polysiloxane segments construct a low surface energy lubricating layer in situ on the coating surface, effectively dissipating mechanical friction stress. Example 3 demonstrates extreme wear resistance at the upper limit of parameters, with a wear life of up to 900 cycles accompanied by extremely small wrapping wrinkles, indicating that although the high-density cross-linked network slightly restricts segment movement, it remains firmly within the flexibility safety threshold. Furthermore, the data from the single-variable comparison sample in Example 1 show that when the amount of rare earth-organic hybrid modifier added is below the lower limit, the wear resistance and high-temperature breakdown voltage both decrease significantly due to insufficient crosslinking network density, failing to form an effective surface lubrication layer and internal anti-oxidation barrier. When the amount added exceeds the upper limit, although the dynamic friction coefficient further decreases, the excessively high inorganic crosslinking density leads to severe embrittlement of the paint film, resulting in severe cracking and peeling in the 1-day cylindrical wrapping test. The accompanying microcrack defects cause the breakdown voltage at room temperature and high temperature to decrease significantly to 9.5kV and 7.0kV, respectively. In contrast, the physical blending method of Comparative Example 2 not only caused severe phase separation and precipitation of the liquid coating within 3 days, but also introduced a large number of micro-defects into the paint film due to the aggregation of its inorganic particles, resulting in a sharp drop in the room temperature breakdown voltage to 8.5kV and brittle peeling during wrapping. The uniform molecular-level distribution of Ce3+ ions in the system of the examples not only did not cause electric field distortion, but also, thanks to its strong charge trapping ability and antioxidant mechanism, increased the high-temperature breakdown voltage to over 10kV and controlled the thermo-oxidative aging weight loss rate to below 1.5%. At the same time, the above examples verified the electrical performance gains after introducing Y3+, Ce4+ and other ions, and cross-verified the significant synergistic effect of rare earth-organic hybrid modifiers.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rare earth modified abrasion resistant enameled wire insulation coating characterized by: Include: Insulating resin base material, rare earth-organic hybrid modifier and organic solvent; The insulating resin base material is 100 parts by weight, and the rare earth-organic hybrid modifier is 1 to 5 parts by weight. The rare earth-organic hybrid modifier is a complex sol formed by the coordination of a polydentate ligand compound containing a carbonyl group and a polysiloxane with reactive end groups with rare earth ions. The polydentate ligand compound is covalently linked to the polysiloxane backbone, and the rare earth ions are coordinately bonded to the polydentate ligand compound. The rare earth ions are selected from Ce3+, Ce4+ or Y3+; the polysiloxane with reactive end groups is an aminosilane coupling agent; the polysiloxane backbone contains Si-O-Si segments. The molar ratio of the aminosilane coupling agent to the carbonyl-containing polydentate ligand compound is 1:1; the molar ratio of the carbonyl-containing polydentate ligand compound to rare earth ions is 3:1 to 4:

1.

2. The rare earth-modified wear-resistant enameled wire insulation coating as described in claim 1, characterized in that: The insulating resin base material is selected from one or more of polyamide-imide resin, polyimide resin, or polyester-imide resin.

3. A method for preparing a rare earth-modified wear-resistant enameled wire insulation coating as described in any one of claims 1-2, characterized in that: include, An aminosilane coupling agent and a polydentate ligand compound containing a carbonyl group were added to an anhydrous alcohol solvent, a dehydrating agent was added, and the reaction was refluxed under heating conditions. The dehydrating agent was removed by filtration to obtain a silane precursor solution containing a Schiff base structure. Soluble rare earth salts are dissolved in a polar aprotic solvent and slowly added dropwise to the silane precursor solution containing Schiff base structure. The reaction is stirred at a constant temperature to allow the Schiff base structure to coordinate with rare earth ions, thereby obtaining a rare earth coordinated silane complex solution. Deionized water and an acidic catalyst were added to the rare earth coordinated silane complex solution, and the pH of the system was adjusted to 3-5. A hydrolysis-condensation reaction was carried out at a constant temperature to form a rare earth-polysiloxane sol intermediate. Subsequently, anhydrous alcohol solvents and small molecule alcohols generated in the reaction were removed from the system by vacuum distillation, and a polar aprotic solvent was added for solvent replacement. The solid content was adjusted to 10%-30% to obtain a rare earth-organic hybrid modifier. The rare earth-organic hybrid modifier is added to a polar solvent solution of an insulating resin base with a solid content of 20% to 40% according to the solid content ratio, and the mixture is stirred at high speed at room temperature to disperse it evenly, thereby obtaining the rare earth modified wear-resistant enameled wire insulation coating.

4. The preparation method according to claim 3, characterized in that: The aminosilane coupling agent is 3-aminopropyltriethoxysilane, the carbonyl-containing polydentate ligand compound is salicylaldehyde, the anhydrous alcohol solvent is anhydrous ethanol, and the dehydrating agent is anhydrous magnesium sulfate.

5. The preparation method according to claim 3, characterized in that: The soluble rare earth salt is cerium acetate hydrate or cerium nitrate hexahydrate; the polar aprotic solvent is N-methylpyrrolidone or N,N-dimethylformamide.

6. The preparation method according to claim 3, characterized in that: The reflux reaction under heating conditions lasts for 4 hours; the stirring reaction under constant temperature is at a temperature of 50℃~80℃ for 6 hours.

7. The preparation method according to claim 3, characterized in that: The acidic catalyst is glacial acetic acid; the amount of deionized water is 0.5 to 1.5 times the molar number of alkoxy groups in the aminosilane coupling agent.

8. The preparation method according to claim 3, characterized in that: The hydrolysis-condensation reaction is carried out at a constant temperature of 40℃ to 60℃ for 4 hours; the vacuum distillation is carried out at a temperature of 60℃.

9. The preparation method according to claim 3, characterized in that: The stirring speed for uniform dispersion at room temperature is 1500 r / min, and the time is 30 min.

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