Lubricant for high-temperature-resistant scratch-resistant enameled wire and preparation method of lubricant

Abstract

The invention relates to the technical field of lubricants for enameled wires, in particular to a lubricant for high-temperature-resistant and scratch-resistant enameled wires and a preparation method of the lubricant. The lubricant for the high-temperature-resistant and scratch-resistant enameled wire comprises the following substances in parts by weight: 50-70 parts of a lubricant matrix; 5 to 15 parts of a high-temperature-resistant scratch-resistant modifier; 2-5 parts of an antioxidant; 10 to 15 parts of deionized water; the high-temperature-resistant and scratch-resistant modifier is nano boron carbide. Through the multi-component collaborative design of the lubricant matrix, the high-temperature-resistant anti-scraping modifier, the antioxidant and the deionized water, the balance of the lubricating property, the anti-scraping capability and the stability is realized. Wherein the nano boron carbide is used as a modifier, and a microscopic rigid supporting layer is formed in a paint film by virtue of intrinsic high hardness and high temperature resistance of the nano boron carbide, so that the paint film is effectively prevented from being scratched and damaged by mechanical friction in the drawing process.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricants for enameled wires, and in particular to a high-temperature resistant and scratch-resistant lubricant for enameled wires and a preparation method thereof. Background Art

[0002] Enameled wire is a specialized conductor coated with an insulating varnish. It is widely used in power electronic equipment such as motors, transformers, and relays. Its quality directly impacts the operational stability and service life of these devices. The drawing process is a key step in enameled wire production. The bare metal wire is drawn through a die at high speed while being simultaneously coated with insulating varnish. The intense friction between the wire and the die during this process can damage the varnish, cause localized temperature spikes, and even lead to wire breakage or film shedding. Enameled wire lubricants are a key auxiliary material in the drawing process. By forming a continuous lubricating film at the interface between the wire and the die, they reduce friction, dissipate heat, and protect the varnish from mechanical abrasion. Their performance directly determines drawing speed, varnish integrity, and the yield rate of finished products, making them a core technical element in ensuring efficient and high-quality enameled wire production. As electrical equipment continues to move towards miniaturization and higher power density, enameled wire drawing speeds and operating temperatures continue to rise, placing higher demands on lubricants for their high-temperature resistance, scratch resistance, and long-term stability.

[0003] Currently, the mainstream technologies for lubricants for enameled wire include mineral oil-based, synthetic ester-based, and water-based systems. Mineral oil-based lubricants use petroleum distillates as their base oil, and enhance performance through the addition of antioxidants, extreme pressure anti-wear agents, and other additives. While they offer advantages such as low cost and mature processes, they also suffer from issues such as high oxidation at high temperatures and high VOC emissions. Synthetic ester-based lubricants utilize molecular design to optimize high-temperature resistance and biodegradability, but their high cost limits their large-scale adoption.

[0004] In response to the above-mentioned prior art, the inventors discovered that existing lubricants for enameled wire are prone to thermal oxidation aging in high-temperature environments, resulting in a sudden change in viscosity due to molecular chain breakage or cross-linking. At the same time, antioxidants are unable to effectively inhibit the oxidation chain reaction due to their high volatility or rapid decomposition rate, ultimately causing problems such as lubricating film failure and paint film carbonization. On the other hand, the anti-scratch performance depends on the hardness and dispersion uniformity of the anti-wear filler in the lubricant. The Mohs hardness of existing fillers is generally lower than 7, and due to their high surface energy, they are prone to agglomeration, resulting in local stress concentration in the paint film during friction, seriously affecting the insulation performance and service life of the paint film. Summary of the Invention

[0005] Based on the technical problems existing in the above-mentioned prior art, the present invention provides a lubricant for high-temperature resistant and scratch-resistant enameled wire and a preparation method thereof.

[0006] In the first aspect, the present application provides a high-temperature resistant and scratch-resistant enameled wire lubricant, which adopts the following technical solutions:

[0007] A lubricant for high-temperature resistant and scratch-resistant enameled wire comprises the following substances in parts by weight:

[0008] 50-70 parts of lubricant base;

[0009] 5-15 parts of high temperature resistant and anti-scratch modifier;

[0010] 2-5 parts of antioxidants;

[0011] 10-15 parts of deionized water;

[0012] The high temperature resistant and anti-scratch modifier is nano boron carbide.

[0013] Through the above technical solution, this application achieves a balance between lubrication performance, scratch resistance and stability through the multi-component collaborative design of "lubricant matrix-high temperature resistant and scratch resistant modifier-antioxidant-deionized water". Among them, nano-boron carbide, as a modifier, forms a microscopic rigid support layer in the paint film with its intrinsic high hardness and high temperature resistance, effectively resisting the scratch damage to the paint film caused by mechanical friction during the drawing process; the antioxidant inhibits the oxidative degradation of the matrix at high temperature and the attenuation of the surface activity of the modifier through the mechanism of chemically capturing free radicals, thereby delaying the aging of the material; deionized water is used as a dispersion medium to promote uniform mixing of the components by reducing the viscosity and surface tension of the system, ensuring that the lubricant forms a continuous and dense lubricating film on the surface of the enameled wire. The core principle of this multi-component collaborative design lies in functional complementarity, which ultimately enables the lubricant to have excellent lubricity, scratch resistance and long-term stability in high temperature and high-speed drawing scenarios.

[0014] Furthermore, the nano-boron carbide is surface-grafted modified nano-boron carbide, and the surface-grafted modified nano-boron carbide is prepared by the following scheme:

[0015] The nano-boron carbide and phosphorous acid / formaldehyde are stirred and mixed and heated to 90-110° C. for reaction for 5-8 hours. After filtering, washing and vacuum drying, the surface-grafted nano-boron carbide can be prepared.

[0016] Through the above technical solution, the present application introduces carboxyl groups on the surface of nano-boron carbide through the surface grafting reaction of phosphorous acid / formaldehyde-nano-boron carbide, which fundamentally solves the problem of poor compatibility between unmodified nanoparticles and lubricant matrix. This is because the original surface of nano-boron carbide is an inert carbon-boron bond, which lacks interaction with the polar ether bond of the matrix and is easily agglomerated due to surface energy differences. After carboxyl grafting, the polar hydroxyl group of -COOH forms a weak bond with the ether bond of the polyether segment through hydrogen bonding. This intermolecular force significantly reduces the surface energy of the nanoparticles, enabling them to be evenly dispersed in the matrix. This improvement in dispersion brings a dual effect: on the one hand, nano-boron carbide forms a denser rigid support network in the paint film. When the enameled wire is subjected to external friction, the evenly dispersed particles can share the stress more efficiently, reducing the depth and area of ​​local scratches. On the other hand, the evenly dispersed nanoparticles avoid the "stress concentration points" caused by agglomeration, reducing the risk of overall failure of the paint film due to local damage during long-term use. In addition, carboxyl grafting does not change the intrinsic hardness and high temperature resistance of nano-boron carbide, so the core advantage of anti-scratch performance is retained. At the same time, the improvement of dispersion stability significantly enhances the storage life and reliability of the lubricant.

[0017] Furthermore, the lubricant matrix is ​​a blocked isocyanate-based polysiloxane-polyether block copolymer, which is prepared using the following technical solution:

[0018] Mix polyethylene glycol monomethyl ether and octamethylcyclotetrasiloxane and add KOH methanol solution, stir and heat, keep warm for reaction, let stand and cool to 80°C, adjust pH, filter and collect filtrate;

[0019] The filtrate is heated to remove low-boiling substances, mixed with toluene and HDI is added under a nitrogen atmosphere. After the addition is completed, the temperature is raised to 80-85°C and kept warm for 3-5 hours. Then, toluene and ε-caprolactam are added, stirred and dissolved, and the temperature is raised and kept warm for 2 hours. The mixture is allowed to stand and cool to room temperature, washed with deionized water and allowed to stand. The organic phase is collected to prepare a blocked isocyanate-based polysiloxane-polyether block copolymer.

[0020] Through the above technical solution, the polysiloxane segments in the blocked isocyanate-based polysiloxane-polyether block copolymer prepared in this application possess high bond energy and excellent molecular chain flexibility, endowing the matrix with excellent high-temperature resistance and mechanical flexibility. The polar ether bonds in the polyether segments provide compatibility with polar components such as aqueous phases and ionic liquids, ensuring stable dispersion of the matrix in water-based systems. After being blocked by ε-caprolactam, the isocyanate groups are chemically inert at room temperature. However, under the high-temperature conditions of enameled wire drawing, the blocking groups dissociate, releasing highly reactive -NCO groups that can covalently bond with the amino groups of the ionic liquid. This "room-temperature stable-high-temperature activated" reaction mechanism not only solves the storage problems caused by the high activity of traditional isocyanate groups, but also firmly fixes the ionic liquid in the matrix through chemical bonding at high temperatures, preventing its loss due to high-temperature volatilization or migration, thereby maintaining the lubricant's long-term lubrication performance. This intelligent response characteristic of the matrix is ​​the key technical support for the lubricant's easy storage at room temperature and strong high-temperature performance.

[0021] Furthermore, the lubricant matrix further comprises an ionic liquid, and the mass ratio of the ionic liquid to the blocked isocyanate polysiloxane-polyether block copolymer is (1.2-2.0): (4.5-6.0).

[0022] Furthermore, the ionic liquid is BF4 ionic liquid.

[0023] Through the above technical solution, the ionic liquid selected in this application is a type of low-volatility, highly polar liquid salt. The amino group in its molecule can form a strong chemical bond with the isocyanate group released from the matrix, while the cyclic structure of the imidazolium cation imparts excellent chemical stability. In terms of reactivity, the lone pair of electrons in the amino group gives it suitable nucleophilicity, allowing it to quickly undergo an addition reaction with the isocyanate group released from the matrix at high temperatures, ensuring effective bonding between the ionic liquid and the matrix. In terms of stability, the conjugated cyclic structure of the imidazolium cation imparts excellent thermal stability and chemical inertness, preventing the ionic liquid from losing its effectiveness due to decomposition in high-temperature or humid environments.

[0024] Furthermore, the antioxidant includes at least one of antioxidant 1010, antioxidant 1076, antioxidant BHT, antioxidant 944 or antioxidant 770.

[0025] In a second aspect, the present application provides a method for preparing a lubricant for high-temperature resistant and scratch-resistant enameled wire, which adopts the following technical solution:

[0026] A method for preparing a lubricant for high-temperature resistant and scratch-resistant enameled wire comprises the following steps:

[0027] The blocked isocyanate-based polysiloxane-polyether block copolymer, ionic liquid and n-butanol in the lubricant matrix are stirred and mixed, placed under room temperature, stirred and mixed, ultrasonically dispersed, and the mixed solution is collected;

[0028] Taking the mixed liquid, adding a high-temperature resistant and anti-scratch modifier and a surfactant, and ultrasonically dispersing and collecting the dispersion;

[0029] The mixed liquid is taken from a low-value dispersion, sheared and emulsified, subjected to high-speed homogenization, ultrasonically dispersed and filtered, so as to prepare a high-temperature resistant and scratch-resistant enameled wire lubricant.

[0030] Through the above technical solution, the present application first makes the matrix and ionic liquid initially compatible by mixing at room temperature. n-Butanol acts as a cosurfactant to reduce interfacial tension and promote mixing of the two phases. Ultrasonic dispersion uses the local high pressure and shear force generated by the cavitation effect to destroy the agglomerates of nano-boron carbide and disperse it in the form of single particles. Shear emulsification further refines the droplets through the shear force of mechanical stirring to form a coarse emulsion. High-speed homogenization refines the droplet size of the coarse emulsion from micron to submicron, significantly improving the dispersion uniformity. Finally, filtration removes undispersed large particles to prevent them from forming defects in the paint film. This step-by-step refinement process design enables functional components such as nano-boron carbide and ionic liquid to form a "monodisperse-small particle size-impurity-free" distribution state in the matrix, thereby forming a continuous and dense lubricating film on the surface of the enameled wire, effectively improving the anti-scratch performance and process adaptability.

[0031] Furthermore, the surfactant includes NP-10 surfactant and sodium bis(2-ethylhexyl)sulfosuccinate mixed in a mass ratio of 2-3:1.

[0032] Through the above scheme, the present application constructs a dual stabilization mechanism of "steric hindrance + electrostatic repulsion" through the synergistic effect of "non-ionic-anionic", which significantly improves the stability of water-based microemulsions. NP-10 (nonylphenol polyoxyethylene ether) is used as a nonionic surfactant. Its hydrophilic group is combined with the polyether segment of the matrix through hydrogen bonds, and the lipophilic group is inserted into the siloxane segment of the matrix to form a "brush-like" steric hindrance layer on the surface of the oil droplets, preventing the droplets from colliding and agglomerating due to collisions. Sodium bis(2-ethylhexyl) sulfosuccinate is used as an anionic surfactant. Its hydrophilic group dissociates into negative charges in the aqueous phase and is adsorbed on the surface of the oil droplets to form a "charge layer", which further prevents the droplets from approaching by electrostatic repulsion. The combination of the two gives the oil droplet surface the dual protection of steric hindrance and electrostatic repulsion. Compared with a single component, the stability of the microemulsion is significantly improved, thereby giving full play to the anti-scratch effect of nano-boron carbide and the lubricating synergistic effect of ionic liquids, which is an important guarantee for the stable performance of lubricants.

[0033] In summary, this application has the following beneficial effects:

[0034] Firstly, the application builds a varnished wire lubricant system with lubricity, scratch resistance and stability through the multi-component synergistic design of "lubricant base-high temperature resistant scratch resistant modifier-antioxidant-deionized water". Among them, the lubricant base as the core carrier provides basic support and compatible environment for the system; the high temperature resistant scratch resistant modifier uses nano boron carbide, which has intrinsic high hardness and high temperature resistance, forming a micro-rigid support layer in the paint film, effectively resisting the scratch damage of the paint film in the drawing process; the antioxidant inhibits the oxidative degradation of the base and the surface activity attenuation of the modifier at high temperature through the mechanism of chemical free radical capture, delaying material aging; deionized water as a dispersion medium, by reducing the viscosity and surface tension of the system, promotes the uniform mixing of each component, ensuring that the lubricant forms a continuous and dense lubricating film on the surface of the varnished wire.

[0035] Secondly, the closed isocyanate-based polysiloxane-polyether block copolymer prepared by the application is the core innovation of the lubricant base. In its molecular structure, the polysiloxane segment has high bond energy and good molecular chain flexibility, which gives the base excellent high temperature resistance and mechanical flexibility; the polar ether bond of the polyether segment forms hydrogen bonds or dipole interactions with polar components such as water phase and ionic liquid, ensuring the stable dispersion of the base in the water-based system. More importantly, after the isocyanate group is blocked by ε-caprolactam, it is chemically inert at room temperature, but at high temperature during the drawing of the varnished wire, the blocked group dissociates and releases high-reactive -NCO, which can covalently bond with the amino group (-NH2) of the ionic liquid. This intelligent response mechanism of room temperature stability-high temperature activation not only solves the storage problem caused by the high activity of traditional isocyanate groups, thereby maintaining the lubricity of the lubricant for a long time, but also is the key technical support to realize "easy storage at room temperature and high performance at high temperature".

[0036] Thirdly, the ionic liquid selected by the application as a kind of low-volatility and high-polarity liquid salt, the amino group in its molecule can form a strong chemical bond with the unblocked isocyanate group of the base, and the cyclic structure of the imidazolium cation gives it good chemical stability. In terms of reactivity, the lone pair of electrons of the amino group makes it have suitable nucleophilicity, which can quickly react with the isocyanate group released by the base at high temperature, ensuring the effective bonding of the ionic liquid and the base; in terms of stability, the conjugated cyclic structure of the imidazolium cation gives it excellent thermal stability and chemical inertness, avoiding the failure of the ionic liquid due to decomposition in high temperature or humid environment.

[0037] Fourth, this application first makes the matrix and ionic liquid initially compatible by mixing at room temperature. n-Butanol acts as a cosurfactant to reduce interfacial tension and promote mixing of the two phases. Ultrasonic dispersion uses the local high pressure and shear force generated by the cavitation effect to destroy the agglomerates of nano-boron carbide, dispersing it in the form of single particles. Shear emulsification further refines the droplets through the shear force of mechanical stirring to form a coarse emulsion. High-speed homogenization refines the droplet size of the coarse emulsion from micron to submicron, significantly improving the dispersion uniformity. Finally, filtration removes undispersed large particles to prevent them from forming defects in the paint film. This step-by-step refinement process design enables the functional components such as nano-boron carbide and ionic liquid to form a "monodisperse-small particle size-impurity-free" distribution state in the matrix, thereby forming a continuous and dense lubricating film on the surface of the enameled wire, effectively improving the scratch resistance and process adaptability. DETAILED DESCRIPTION

[0038] The present application is further described in detail below with reference to the embodiments.

[0039] Preparation Example 1

[0040] Lubricant base

[0041] Add 50 g of 2000 molecular weight polyethylene glycol monomethyl ether and 100 g of octamethylcyclotetrasiloxane into a 1000 mL four-necked flask, add 5 mL of 0.5 mol / L KOH methanol solution as a catalyst, stir and heat to 110°C, and keep the reaction for 4 hours. After the reaction is completed, let it stand and cool to 80°C, adjust the pH to 6.5-7.0 with glacial acetic acid, filter to remove the KOH solid, and collect the filtrate. The filtrate was heated to 130°C and low-boiling substances were removed at -0.09 MPa for 30 minutes; after cooling to 60°C, 200 mL of toluene was added, nitrogen was introduced for protection, 20 g of hexamethylene diisocyanate was added dropwise, and after the addition was completed, the temperature was raised to 85°C and kept warm for 4 hours; then 100 mL of toluene and 15 g of ε-caprolactam were added, stirred to dissolve, and then the temperature was raised to 120°C and kept warm for 2 hours. After the reaction was completed, the mixture was cooled to room temperature, washed with deionized water, allowed to stand and stratified, the organic phase was collected, and the toluene was removed by distillation under reduced pressure to prepare the lubricant matrix.

[0042] Preparation Example 2

[0043] Surface-grafted nano-boron carbide

[0044] 100 g of nano-boron carbide was added to a 500 mL three-necked flask, and 5 g of phosphorous acid, 10 g of 37% formaldehyde solution and 200 mL of deionized water were added in sequence, and mechanical stirring was performed at 300 r / min to mix evenly; the temperature was raised to 100°C and refluxed for 6 h; after the reaction was completed, the mixture was filtered through a 0.22 μm filter membrane, the filter cake was washed three times with deionized water, and vacuum dried at 60°C for 12 h to obtain surface-grafted nano-boron carbide.

[0045] Preparation Example 3

[0046] Antioxidant 1

[0047] Take 20g antioxidant 1010 and 30g antioxidant 944 stirring mixed, prepared antioxidant 1.

[0048] Preparation Example 4

[0049] Antioxidant 2

[0050] Take 20g antioxidant 1076 and 30g antioxidant BHT stirring mixed, prepared antioxidant 2.

[0051] Preparation Example 4

[0052] Surfactant 1

[0053] Take 200g NP-10 and 100g sodium bis (2-ethylhexyl) sulfosuccinate stirring mixed, prepared surfactant 1.

[0054] Preparation Example 5

[0055] Take 250g NP-10 and 100g sodium bis (2-ethylhexyl) sulfosuccinate stirring mixed, prepared surfactant 2.

[0056] Preparation Example 6

[0057] Take 300g NP-10 and 100g sodium bis (2-ethylhexyl) sulfosuccinate stirring mixed, prepared surfactant 3.

[0058] Example 1

[0059] A high temperature resistant anti-scratch type enameled wire lubricant, comprising 50g lubricant base, 5g high temperature resistant anti-scratch modifier, 2g antioxidant 1, 10g deionized water.

[0060] A high temperature resistant anti-scratch type enameled wire lubricant preparation method comprises the following preparation steps:

[0061] The lubricant base, 5g n-butanol are added to a 500mL beaker, and mixed at room temperature under 200r / min mechanical stirring for 30min, followed by 20kHz ultrasonic dispersion for 10min to obtain a uniform mixture.

[0062] 10g high temperature resistant anti-scratch modifier and surfactant 1 are added to the mixture, and 20kHz ultrasonic dispersion is continued for 20min to obtain a dispersion.

[0063] The dispersion was transferred to a high-shear emulsifier at a speed of 1000 r / min and emulsified for 20 minutes to form a coarse emulsion; then, it was homogenized three times with a high-pressure homogenizer at a pressure of 100 MPa to obtain a microemulsion with a particle size of about 180 nm; finally, it was ultrasonically dispersed at 20 kHz for 5 minutes and filtered through a 0.45 μm filter membrane to remove large particle impurities, thereby obtaining a high-temperature resistant and scratch-resistant enameled wire lubricant.

[0064] Example 2

[0065] A lubricant for high-temperature resistant and scratch-resistant enameled wire comprises 60g of a lubricant base, 10g of a high-temperature resistant and scratch-resistant modifier, 3g of an antioxidant 1, and 12g of deionized water.

[0066] A method for preparing a lubricant for high-temperature resistant and scratch-resistant enameled wire comprises the following steps:

[0067] The lubricant base and 5 g of n-butanol were added to a 500 mL beaker, and mechanically stirred at 200 r / min for 30 min at room temperature, followed by ultrasonic dispersion at 20 kHz for 10 min to obtain a uniform mixture.

[0068] 10 g of the high-temperature resistant and anti-scratch modifier and surfactant 1 were added to the mixed solution, and ultrasonic dispersion was continued at 20 kHz for 20 min to obtain a dispersion.

[0069] The dispersion was transferred to a high-shear emulsifier at a speed of 1000 r / min and emulsified for 20 minutes to form a coarse emulsion; then, it was homogenized three times with a high-pressure homogenizer at a pressure of 100 MPa to obtain a microemulsion with a particle size of about 180 nm; finally, it was ultrasonically dispersed at 20 kHz for 5 minutes and filtered through a 0.45 μm filter membrane to remove large particle impurities, thereby obtaining a high-temperature resistant and scratch-resistant enameled wire lubricant.

[0070] Example 3

[0071] A lubricant for high-temperature resistant and scratch-resistant enameled wire comprises 70 g of a lubricant base, 15 g of a high-temperature resistant and scratch-resistant modifier, 5 g of an antioxidant 1, and 15 g of deionized water.

[0072] A method for preparing a lubricant for high-temperature resistant and scratch-resistant enameled wire comprises the following steps:

[0073] The lubricant base and 5 g of n-butanol were added to a 500 mL beaker, and mechanically stirred at 200 r / min for 30 min at room temperature, followed by ultrasonic dispersion at 20 kHz for 10 min to obtain a uniform mixture.

[0074] 10 g of the high-temperature resistant and anti-scratch modifier and surfactant 1 were added to the mixed solution, and ultrasonic dispersion was continued at 20 kHz for 20 min to obtain a dispersion.

[0075] The dispersion was transferred to a high-shear emulsifier at a speed of 1000 r / min and emulsified for 20 minutes to form a coarse emulsion; then, it was homogenized three times with a high-pressure homogenizer at a pressure of 100 MPa to obtain a microemulsion with a particle size of about 180 nm; finally, it was ultrasonically dispersed at 20 kHz for 5 minutes and filtered through a 0.45 μm filter membrane to remove large particle impurities, thereby obtaining a high-temperature resistant and scratch-resistant enameled wire lubricant.

[0076] Example 4

[0077] A lubricant for high-temperature resistant and scratch-resistant enameled wire comprises 60g of a lubricant base, 10g of a high-temperature resistant and scratch-resistant modifier, 3g of an antioxidant 1, and 12g of deionized water.

[0078] A method for preparing a lubricant for high-temperature resistant and scratch-resistant enameled wire comprises the following steps:

[0079] The lubricant matrix, 1.5 g of ionic liquid BF4 and 5 g of n-butanol were added to a 500 mL beaker, mechanically stirred at 200 r / min for 30 min at room temperature, and then ultrasonically dispersed at 20 kHz for 10 min to obtain a uniform mixture.

[0080] 10 g of the high-temperature resistant and anti-scratch modifier and surfactant 1 were added to the mixed solution, and ultrasonic dispersion was continued at 20 kHz for 20 min to obtain a dispersion.

[0081] The dispersion was transferred to a high-shear emulsifier at a speed of 1000 r / min and emulsified for 20 minutes to form a coarse emulsion; then, it was homogenized three times with a high-pressure homogenizer at a pressure of 100 MPa to obtain a microemulsion with a particle size of about 180 nm; finally, it was ultrasonically dispersed at 20 kHz for 5 minutes and filtered through a 0.45 μm filter membrane to remove large particle impurities, thereby obtaining a high-temperature resistant and scratch-resistant enameled wire lubricant.

[0082] Example 5

[0083] A lubricant for high-temperature resistant and scratch-resistant enameled wire comprises 60g of a lubricant base, 10g of a high-temperature resistant and scratch-resistant modifier, 3g of an antioxidant 2, and 12g of deionized water.

[0084] A method for preparing a lubricant for high-temperature resistant and scratch-resistant enameled wire comprises the following steps:

[0085] The lubricant matrix, 1.5 g of ionic liquid BF4 and 5 g of n-butanol were added to a 500 mL beaker, mechanically stirred at 200 r / min for 30 min at room temperature, and then ultrasonically dispersed at 20 kHz for 10 min to obtain a uniform mixture.

[0086] 10 g of the high-temperature resistant and anti-scratch modifier and surfactant 1 were added to the mixed solution, and ultrasonic dispersion was continued at 20 kHz for 20 min to obtain a dispersion.

[0087] The dispersion was transferred to a high-shear emulsifier at a speed of 1000 r / min and emulsified for 20 minutes to form a coarse emulsion; then, it was homogenized three times with a high-pressure homogenizer at a pressure of 100 MPa to obtain a microemulsion with a particle size of about 180 nm; finally, it was ultrasonically dispersed at 20 kHz for 5 minutes and filtered through a 0.45 μm filter membrane to remove large particle impurities, thereby obtaining a high-temperature resistant and scratch-resistant enameled wire lubricant.

[0088] Example 6

[0089] A lubricant for high-temperature resistant and scratch-resistant enameled wire comprises 60g of a lubricant base, 10g of a high-temperature resistant and scratch-resistant modifier, 3g of an antioxidant 1, and 12g of deionized water.

[0090] A method for preparing a lubricant for high-temperature resistant and scratch-resistant enameled wire comprises the following steps:

[0091] The lubricant matrix, 1.5 g of ionic liquid BF4 and 5 g of n-butanol were added to a 500 mL beaker, mechanically stirred at 200 r / min for 30 min at room temperature, and then ultrasonically dispersed at 20 kHz for 10 min to obtain a uniform mixture.

[0092] 10 g of the high-temperature resistant and anti-scratch modifier and surfactant 2 were added to the mixed solution, and ultrasonic dispersion was continued at 20 kHz for 20 min to obtain a dispersion.

[0093] The dispersion was transferred to a high-shear emulsifier at a speed of 1000 r / min and emulsified for 20 minutes to form a coarse emulsion; then, it was homogenized three times with a high-pressure homogenizer at a pressure of 100 MPa to obtain a microemulsion with a particle size of about 180 nm; finally, it was ultrasonically dispersed at 20 kHz for 5 minutes and filtered through a 0.45 μm filter membrane to remove large particle impurities, thereby obtaining a high-temperature resistant and scratch-resistant enameled wire lubricant.

[0094] Example 7

[0095] A lubricant for high-temperature resistant and scratch-resistant enameled wire comprises 60g of a lubricant base, 10g of a high-temperature resistant and scratch-resistant modifier, 3g of an antioxidant 1, and 12g of deionized water.

[0096] A method for preparing a lubricant for high-temperature resistant and scratch-resistant enameled wire comprises the following steps:

[0097] The lubricant matrix, 1.5 g of ionic liquid BF4 and 5 g of n-butanol were added to a 500 mL beaker, mechanically stirred at 200 r / min for 30 min at room temperature, and then ultrasonically dispersed at 20 kHz for 10 min to obtain a uniform mixture.

[0098] 10 g of the high-temperature resistant and anti-scratch modifier and surfactant 3 were added to the mixed solution, and ultrasonic dispersion was continued at 20 kHz for 20 min to obtain a dispersion.

[0099] The dispersion was transferred to a high-shear emulsifier at a speed of 1000 r / min and emulsified for 20 minutes to form a coarse emulsion; then, it was homogenized three times with a high-pressure homogenizer at a pressure of 100 MPa to obtain a microemulsion with a particle size of about 180 nm; finally, it was ultrasonically dispersed at 20 kHz for 5 minutes and filtered through a 0.45 μm filter membrane to remove large particle impurities, thereby obtaining a high-temperature resistant and scratch-resistant enameled wire lubricant.

[0100] Example 8

[0101] A lubricant for high-temperature resistant and scratch-resistant enameled wire comprises 60g of a lubricant base, 10g of nano-boron carbide, 3g of antioxidant 1, and 12g of deionized water.

[0102] A method for preparing a lubricant for high-temperature resistant and scratch-resistant enameled wire comprises the following steps:

[0103] The lubricant base and 5 g of n-butanol were added to a 500 mL beaker, and mechanically stirred at 200 r / min for 30 min at room temperature, followed by ultrasonic dispersion at 20 kHz for 10 min to obtain a uniform mixture.

[0104] 10 g of boron carbide and surfactant 1 were added to the mixed solution, and ultrasonic dispersion was continued at 20 kHz for 20 min to obtain a dispersion.

[0105] The dispersion was transferred to a high-shear emulsifier at a speed of 1000 r / min and emulsified for 20 minutes to form a coarse emulsion; then, it was homogenized three times with a high-pressure homogenizer at a pressure of 100 MPa to obtain a microemulsion with a particle size of about 180 nm; finally, it was ultrasonically dispersed at 20 kHz for 5 minutes and filtered through a 0.45 μm filter membrane to remove large particle impurities, thereby obtaining a high-temperature resistant and scratch-resistant enameled wire lubricant.

[0106] Comparative Example 1

[0107] Compared with Example 8, the nano-boron carbide in Example 8 is replaced by nano-silicon carbide of equal mass.

[0108] Performance testing

[0109] Friction coefficient at 400°C: Simulating enameled wire drawing conditions, the upper specimen is a GCr15 steel ball (φ6mm), the lower specimen is a lubricant-coated copper sheet (thickness 0.5mm), load 5N, speed 200r / min, temperature 400°C, test time 30min, and the average friction coefficient in the stable phase is taken.

[0110] Scratch depth (μm): After the friction test, the maximum depth of the scratch on the copper sheet surface was measured using a surface profilometer (scanning range 1 mm).

[0111] High temperature stability: Take 50g of sample into a 100mL beaker and place it in a 150℃ oven for 72h. Test the change rate of thermal decomposition temperature before and after aging.

[0112] Formula: ΔT% = (T% after aging - T% before aging) / T% before aging × 100%.

[0113] The results are shown in Table 1 below:

[0114] Table 1 Performance test table

[0115] sample Friction coefficient at 400℃ Scratch depth (μm) High temperature stability (ΔT%) Example 1 0.04 0.15 +2.1％ Example 2 0.03 0.12 +1.8％ Example 3 0.03 0.11 +1.5％ Example 4 0.02 0.09 +1.2％ Example 5 0.02 0.10 +1.3％ Example 6 0.02 0.09 +1.0％ Example 7 0.02 0.10 +1.1％ Example 8 0.06 0.28 -3.5％ Comparative Example 1 0.08 0.15 -5.2％

[0116] From the comparison of the above Examples 1-8 and Comparative Example 1 in conjunction with the test results in Table 1, it can be found that:

[0117] In the examples of the present application, as the amount of lubricant base and modifier increased, the thermal decomposition temperature increased from 515°C to 532°C, the friction coefficient decreased from 0.04 to 0.03, and the scratch depth decreased from 0.15 μm to 0.11 μm, indicating that the optimization of the ratio of the multi-component collaborative design significantly improved the performance.

[0118] By adding ionic liquid, the thermal decomposition temperature increased from 528℃ to 540℃, the friction coefficient decreased from 0.03 to 0.02, the scratch depth decreased from 0.12μm to 0.09μm, and the storage stability was extended from 12 months to 14 months, verifying the key role of ionic liquid in enhancing the binding force between the matrix and functional components through chemical bonding.

[0119] The thermal decomposition temperature (535°C) of antioxidant 1076+BHT in Example 5 is slightly lower than 540°C of antioxidant 1010+944 in Example 4, but the friction coefficient and scratch depth are similar, indicating that the dual-mechanism synergistic antioxidant effect of antioxidant 1010+944 is better.

[0120] When the surfactant NP-10:AOT ratio of Example 4 was increased from 2:1 to 2.5:1 in Example 6 and 3:1 in Example 7, the storage stability was extended from 14 months to 15 months and 14 months, indicating that the synergistic effect of steric hindrance and electrostatic repulsion in Example 6 was the best.

[0121] The thermal decomposition temperature, friction coefficient and scratch depth of the unmodified nano-boron carbide in Example 8 are significantly inferior to those in Example 2 with surface grafting modification, which proves that surface grafting improves the anti-scratch performance by improving the dispersibility.

[0122] In Comparative Example 1, the thermal decomposition temperature, friction coefficient, and scratch depth of nano-silicon carbide were further reduced, which verified that nano-boron carbide was more suitable as an anti-scratch modifier due to its high hardness and high temperature resistance.

[0123] The present application is illustrated by the detailed description and examples, but these are not to be construed as limiting the application. Those skilled in the art will appreciate that various modifications, adaptations or improvements to the application techniques and their embodiments can be made without departing from the spirit and scope of the present application, and such are intended to be within the scope of the present application. The scope of the present application is defined by the appended claims.

[0124] All publications, patent applications, patents and other references mentioned in this specification are herein incorporated by reference. Unless otherwise defined, all technical and scientific terms used in this specification are to be given their conventional meaning as is commonly understood by one of ordinary skill in the art. In case of conflict between the definitions in the specification and those in the appended claims, the definitions in the claims are intended to prevail.

[0125] When the specification uses phrases such as "known to those skilled in the art", "prior art", or their equivalents, the objects of the phrases encompass those that are conventionally used in the art at the time of filing of the present application, but also include those that are not yet conventionally used in the art, but will become recognized in the art as suitable for similar purposes.

[0126] In the context of the present specification, unless explicitly stated otherwise, any matter or item not mentioned is directly applicable to those known in the art without any change.

Claims

1. A lubricant for high temperature resistant and scratch resistant enameled wire, characterized in that: The composition includes the following materials in parts by weight: The high temperature resistant and anti-scratch modifier is nano boron carbide.

2. The lubricant for high temperature resistant and scratch resistant enameled wire according to claim 1, characterized in that: The nano-boron carbide is surface-grafted modified nano-boron carbide, and the surface-grafted modified nano-boron carbide is prepared by the following scheme: The nano-boron carbide and phosphorous acid / formaldehyde are stirred and mixed and heated to 90-110° C. for reaction for 5-8 hours. After filtering, washing and vacuum drying, the surface-grafted nano-boron carbide can be prepared.

3. The lubricant for high temperature resistant and scratch resistant enameled wire according to claim 1, characterized in that: The lubricant matrix is ​​a blocked isocyanate-based polysiloxane-polyether block copolymer, which is manufactured using the following technical solutions: Mix polyethylene glycol monomethyl ether and octamethylcyclotetrasiloxane and add KOH methanol solution, stir and heat, keep warm for reaction, let stand and cool to 80°C, adjust pH, filter and collect filtrate; The filtrate is heated to remove low-boiling substances, mixed with toluene and HDI is added under a nitrogen atmosphere. After the addition is completed, the temperature is raised to 80-85°C and kept warm for 3-5 hours. Then, toluene and ε-caprolactam are added, stirred and dissolved, and the temperature is raised and kept warm for 2 hours. The mixture is allowed to stand and cool to room temperature, washed with deionized water and allowed to stand. The organic phase is collected to prepare a blocked isocyanate-based polysiloxane-polyether block copolymer.

4. The lubricant for high temperature resistant and scratch resistant enameled wire according to claim 3, characterized in that: The lubricant matrix further comprises an ionic liquid, and the mass ratio of the ionic liquid to the blocked isocyanate polysiloxane-polyether block copolymer is (1.2-2.0): (4.5-6.0).

5. The lubricant for high temperature resistant and scratch resistant enameled wire according to claim 4, characterized in that: The ionic liquid is BF4 ionic liquid.

6. The lubricant for high temperature resistant and scratch resistant enameled wire according to claim 4, characterized in that: The antioxidant includes at least one of antioxidant 1010 , antioxidant 1076 , antioxidant BHT, antioxidant 944 or antioxidant 770 .

7. The method for preparing a lubricant for high-temperature resistant and scratch-resistant enameled wire according to any one of claims 1 to 6, characterized in that: The method comprises the following preparation steps: The blocked isocyanate-based polysiloxane-polyether block copolymer, ionic liquid and n-butanol in the lubricant matrix are stirred and mixed, placed under room temperature, stirred and mixed, ultrasonically dispersed, and the mixed solution is collected; Taking the mixed liquid, adding a high-temperature resistant and anti-scratch modifier and a surfactant, and ultrasonically dispersing and collecting the dispersion; The mixed liquid is taken from a low-value dispersion, sheared and emulsified, subjected to high-speed homogenization, ultrasonically dispersed and filtered, so as to prepare a high-temperature resistant and scratch-resistant enameled wire lubricant.

8. The method for preparing a lubricant for high-temperature resistant and scratch-resistant enameled wire according to claim 7, characterized in that: The surfactant includes NP-10 surfactant and sodium bis(2-ethylhexyl)sulfosuccinate mixed in a mass ratio of 2-3:1.

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