A thin enamel film fine self-adhesive enameled wire and a method for manufacturing the same

Abstract

This invention relates to the field of enameled wire manufacturing, and discloses a thin-film micro-fine self-adhesive enameled wire and its preparation method. The wire comprises, from the inside out, a central conductor, a composite insulation layer, and an outer self-adhesive layer. The composite insulation layer contains 0.5% to 5.0% modified two-dimensional nanosheets, which are highly oriented and form a labyrinthine structure. During preparation, a high-shear force mold coating is used to induce the orientation of the nanosheets. This invention utilizes the labyrinth effect generated by the oriented nanosheets to increase the breakdown voltage and reduce the pinhole rate without increasing the thickness. Simultaneously, it constructs an efficient heat conduction path, reduces the temperature rise of the conductor, prevents self-adhesive layer failure caused by heat accumulation inside the conductor, and the thin-film design allows for tighter coil winding, improving space utilization.

Description

Technical Field

[0001] This invention belongs to the field of enameled wire manufacturing, specifically relating to a thin-film micro-fine self-adhesive enameled wire and its preparation method. Background Technology

[0002] Traditional micro-enameled wires typically use high-molecular resins such as polyurethane, polyesterimide, or polyamideimide as the main insulation layer, and employ a multi-coating process to build a protective barrier on the conductor surface. In long-term technical practice, improving insulation reliability mainly relies on the dielectric strength of the resin material itself and the cumulative thickness of the enamel film.

[0003] When the diameter of enameled wire enters the micro or even ultra-micro range (e.g., 0.02 mm and below), the forced reduction in film thickness leads to abnormal surface tension effects during drying and curing, easily resulting in uneven film formation and microscopic pinholes or structurally loose areas. In extremely thin states, the arrangement of long polymer chains is random, lacking physical structures to impede charge migration, making it easy for electrons to penetrate weak points and trigger dielectric breakdown. This inherent contradiction between thin film and high insulation reliability often results in traditional solutions exhibiting lower breakdown voltage limits and unstable quality consistency when facing high-voltage surges or complex electromagnetic environments.

[0004] Due to the extremely small cross-sectional area of ​​the micro-wires, the current density carried per unit cross-sectional area is extremely high, resulting in a drastic instantaneous temperature rise during operation. The low thermal conductivity of traditional polymer insulating resins (typically around 0.2 W / m·K) acts as a heat dissipation barrier. Heat accumulates rapidly inside the micro-wires, making it difficult to conduct and diffuse axially or radially through the insulation layer. This localized heat accumulation effect not only accelerates the thermal aging and degradation of the insulating substrate but also directly causes the self-adhesive layer on the outer layer of the micro-enameled wire to reach its thermal softening point prematurely, leading to a collapse in the mechanical strength of the entire coil structure or interlayer short-circuit failure. Summary of the Invention

[0005] To address the technical bottlenecks faced by existing micro-enameled wires in the thin-film process, such as reduced insulation reliability, increased pinhole density, and heat buildup and premature failure of the self-adhesive layer due to excessive current density, this invention provides a thin-film micro-enameled self-adhesive wire and its preparation method.

[0006] This invention provides a thin-film, fine, self-adhesive enameled wire, comprising, from the inside out, a central conductor, a composite insulation layer, and an outer self-adhesive layer. The thin-film design of this enameled wire allows for tighter coil winding, effectively improving the space utilization of the coil assembly and meeting the requirements of highly integrated electromagnetic components.

[0007] The center conductor is made of oxygen-free copper wire or high-strength copper alloy wire, with a wire diameter between 0.010 mm and 0.050 mm. The surface roughness Ra value of the center conductor is controlled below 0.05 μm to ensure the uniformity of the thickness of the subsequent coating layer. Before entering the coating process, the center conductor undergoes online continuous annealing at a temperature set between 350°C and 550°C in a nitrogen-protected atmosphere to eliminate work hardening stress and obtain an elongation at break greater than 35%.

[0008] The composite insulating layer tightly covers the outer peripheral surface of the central conductor, and its radial thickness is set between 0.002 mm and 0.008 mm. The composite insulating layer consists of an insulating resin matrix and modified two-dimensional nanosheets dispersed within the insulating resin matrix. The insulating resin matrix is ​​one or more of polyamide-imide resin, polyester-imide resin, or polyurethane resin. The modified two-dimensional nanosheets constitute 0.5% to 5.0% of the composite insulating layer by mass percentage. The modified two-dimensional nanosheets are formed by surface-modifying hexagonal boron nitride nanosheets or reduced graphene oxide microsheets.

[0009] The hexagonal boron nitride nanosheets have an average aspect ratio between 200 and 800, and their sheet thickness ranges from 3 nm to 15 nm. The reduced graphene oxide microsheets have a carbon-to-oxygen atomic ratio greater than 20:1, and their specific surface area ranges from 400 m² / g to 800 m² / g. The modified two-dimensional nanosheets have a silane coupling agent molecular layer grafted onto their surface. The silane coupling agent is one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, or vinyltrimethoxysilane. Through the bridging effect of the silane coupling agent, active functional groups are formed on the surface of the two-dimensional nanosheets, thereby forming covalent bonds with the molecular chains of the insulating resin matrix during the curing process of the coating film, constructing a three-dimensional cross-linked network structure.

[0010] In this invention, the modified two-dimensional nanosheets inside the composite insulating layer exhibit a highly oriented arrangement. The plane of the modified two-dimensional nanosheets forms an angle of less than 5 degrees with the axial direction of the central conductor, and they display a layered, repetitive, labyrinthine arrangement in the radial cross-section. This arrangement increases the tortuosity of the path through which electrons penetrate the insulating layer under the influence of an electric field, thereby increasing the dielectric breakdown voltage in the thin-film state through physical obstruction. Simultaneously, due to the extremely high thermal conductivity of the two-dimensional nanosheets in the in-plane direction, the oriented nanosheets construct continuous heat conduction channels within the film, allowing the high-temperature heat generated by the central conductor to be rapidly conducted radially to the film surface and quickly diffused axially, reducing the local operating temperature of the conductor.

[0011] The outer self-adhesive layer covers the outer surface of the composite insulation layer, and its thickness is set between 0.001 mm and 0.004 mm. The outer self-adhesive layer is made of hot-melt or solvent-activated modified polyamide resin or modified epoxy resin. The softening point temperature of the outer self-adhesive layer is set between 120 degrees Celsius and 220 degrees Celsius, and its thermomechanical properties are matched with those of the inner composite insulation layer to ensure that interlayer delamination does not occur under high-temperature operating conditions.

[0012] This invention provides a method for preparing the above-mentioned thin-film micro-fine self-adhesive enameled wire, specifically including the following steps: Step 1: Preparation of Functionalized Nanoparticle Paint. First, a modified two-dimensional nanosheet suspension is prepared. Five to 15 parts by weight of two-dimensional nanosheet powder are dispersed in 85 to 95 parts by weight of a solvent, wherein the solvent is N-methylpyrrolidone or dimethylacetamide. A silane coupling agent, accounting for 2% to 8% of the nanosheet mass, is added to the mixture, and high-energy ultrasonic treatment is performed at a constant temperature of 40°C to 60°C, with an ultrasonic power set at 800W to 1500W, for 4 to 8 hours to achieve nanosheet exfoliation and surface functionalization modification. Subsequently, the modified two-dimensional nanosheet suspension is added to an insulating resin paint at a predetermined ratio, and high-speed stirring is performed using a planetary mixer at a speed set at 2000 to 5000 rpm for 2 hours to obtain a thixotropic functionalized nanoparticle paint. The viscosity of the functionalized nano-coating at 25 degrees Celsius is controlled between 150 mPa·s and 450 mPa·s.

[0013] The second step: pretreatment and multi-coating of the center conductor. The center conductor is softened in an online annealing furnace at a linear speed of 100 to 800 meters per minute. The annealed conductor immediately enters a closed coating chamber. This invention employs a multi-coating process, with a total of 8 to 16 coating passes. In the first 4 to 6 steps of coating the composite insulation layer, a high-shear-force mold coating method is used.

[0014] The high-shear force mold's die hole design includes a guiding section, a compression section, and a sizing section. The half-compression angle of the compression section is set between 3 and 8 degrees. When the central conductor carrying the functionalized nano-coating passes through the die hole at high speed, under the action of the strong shear stress field generated in the compression section, the randomly distributed two-dimensional nanosheets inside the coating rotate and orient themselves, forcing their planar orientation to be consistent with the direction of the conductor's movement, thereby achieving a regular orientation arrangement inside the coating film.

[0015] Step 3: Gradient Temperature Controlled Baking and Curing. Each coated lead wire needs to be baked in a vertical or horizontal oven. The oven is divided into a solvent evaporation zone, a pre-curing zone, a deep curing zone, and a cooling zone along the direction of lead wire movement. The temperature in the solvent evaporation zone is set between 150°C and 220°C. By controlling the hot air circulation speed, the organic solvent inside the coating film evaporates in a gradient from the inside to the outside, preventing pinholes or bubbles caused by excessively rapid surface skinning. The temperature in the pre-curing zone is set between 250°C and 320°C, initiating the initial cross-linking of resin molecules. The temperature in the deep curing zone is set between 350°C and 450°C, allowing the resin matrix to fully cure and form stable chemical bonds with the modified two-dimensional nanosheets.

[0016] Step 4: Coating and winding of the outer self-adhesive layer. After the composite insulation layer has fully cured and cooled to room temperature, the outer self-adhesive layer is applied by dip coating or mold coating. The baking temperature of the self-adhesive layer varnish is set between 120°C and 180°C to ensure that the self-adhesive layer resin reaches semi-curing or full curing without damaging the physical structure of the internal insulation layer. Finally, the finished enameled wire is wound into a spool using a constant tension winding machine. The winding tension is set between 0.05N and 0.5N to avoid excessive radial pressure that could cause deformation of the extremely thin varnish film.

[0017] In a preferred embodiment of the present invention, the composite insulating layer is prepared by layering nano-coatings of different concentrations. In the inner composite insulating layer near the central conductor, the content of two-dimensional nanosheets is set to 1.0% to 2.0% to enhance interfacial bonding and provide basic insulation performance. In the middle composite insulating layer, the content of two-dimensional nanosheets is increased to 3.0% to 5.0%, strengthening the labyrinth effect and thermal conductivity through high-density nanosheet stacking. The outermost composite insulating layer uses pure resin coatings or coatings with extremely low nanosheet content to ensure surface smoothness and compatibility with the self-adhesive layer.

[0018] In another embodiment of the present invention, the ratio of the length of the sizing section to the diameter of the die hole in the high-shear force mold is set to 3:1 to 5:1. This long sizing section design can prolong the time that shear stress acts on the nanosheets, further improve the regularity of the nanosheets in the coating film thickness direction, and ensure the consistency of performance throughout the entire coating film length.

[0019] In this invention, the technical effects produced by the introduction and orientation of two-dimensional nanosheets are achieved through the following physical mechanism: Regarding electrical insulation performance, the ultra-thin micro-wire coating exhibits extremely high electric field strength. Traditional spherical or amorphous fillers cannot block the electron breakdown path. This invention utilizes the high aspect ratio of two-dimensional nanosheets to construct multiple parallel barriers within the coating film. When electrons attempt to penetrate the coating film under a strong electric field, the oriented nanosheets possess extremely high dielectric strength and are interwoven, forcing electrons to navigate around these highly obstructive layered structures. The actual migration path length increases several times, even tens of times, compared to the geometric thickness of the coating film. This physical path multiplication dilutes the potential difference per unit path, thereby increasing the breakdown voltage and reducing the probability of pinholes without increasing the total coating film thickness.

[0020] In terms of thermal management performance, the heat generated by the high current density of the micro-wires is isotropic. Traditional polymer coatings have extremely low thermal conductivity, leading to heat accumulation at the interface. The hexagonal boron nitride or graphene microsheets oriented in this invention possess extremely high lattice thermal conductivity. Because the nanosheets form continuous physical contacts or close-range jump points in the axial and circumferential directions, thermal phonons can migrate rapidly along these highly thermally conductive paths. According to thermodynamic conductivity tests, the composite insulation layer provided by this invention exhibits improved radial thermal conductivity and improved axial thermal conductivity compared to pure resin coatings. This slows down the temperature rise rate of the central conductor, preventing premature glass transition temperature of the self-adhesive layer due to heat accumulation inside the wire, and ensuring the structural stability of the coil under extreme operating conditions.

[0021] In terms of mechanical properties and process compatibility, the addition of modified two-dimensional nanosheets is not a simple physical stacking. Through surface silanization treatment, the active groups at the edges of the nanosheets participate in the curing reaction of the coating resin, forming a molecular anchoring effect. This not only enhances the adhesion between the coating film and the central conductor (verified by a scratch test, adhesion is improved by more than 2 levels), but also improves the wear resistance and flexibility of the thin coating film. During the forced stretching and bending process of the winding machine, the oriented nanosheets can undergo microscopic displacement synchronously with the substrate, avoiding coating cracking caused by stress concentration.

[0022] This invention reshapes the microstructure of the insulating layer by introducing two-dimensional nanosheets with a specific particle size distribution and high aspect ratio into an insulating matrix and inducing their directional arrangement using a strong shear coating process. The maze effect is not only limited to physically hindering electron movement paths but also manifests in homogenizing the local electric field. Due to the high dielectric constant of the nanosheets (or a specific dielectric response under a specific formulation), they act as an electric field modulator in the resin matrix, eliminating charge accumulation caused by minute surface irregularities of the conductor and further enhancing the coating's resistance to corona aging.

[0023] In the formulation of the functionalized nano-coating, the solvent degassing process and the coating circulation filtration were strictly controlled. Before entering the coating head, the coating must pass through a precision filter with a filtration accuracy of 1.0 μm to remove any possible micro-agglomerates. This process ensures that there are no macroscopic foreign objects that would cause abrupt changes in dielectric strength within the extremely thin coating film at the 0.002 mm level, thus guaranteeing a high degree of consistency in the performance of the entire axial conductor.

[0024] In the implementation of this invention, the specific performance of the enameled wire can be optimized by adjusting the type and proportion of two-dimensional nanosheets. For example, when improving heat dissipation is the primary goal, the proportion of reduced graphene oxide microsheets can be appropriately increased to utilize their excellent phonon transmission efficiency; when high-voltage insulation is the primary goal, hexagonal boron nitride nanosheets are used as the main component to utilize their excellent intrinsic insulation strength. This flexible adjustment capability based on the same technical concept makes this invention widely applicable to the manufacturing of precision electromagnetic components with different performance requirements.

[0025] The outer self-adhesive layer material formulation further includes trace amounts of leveling agent and antistatic agent. The leveling agent uses a nonionic fluorocarbon surfactant to reduce surface tension during the coating process, ensuring the smoothness of the self-adhesive layer film on the composite insulation layer surface. The addition of the antistatic agent prevents electrostatic adsorption caused by friction during high-speed winding of the fine wires, which could lead to uneven coil wiring or mechanical damage to the varnish film.

[0026] In the technical system of this invention, when the content of modified two-dimensional nanosheets is less than 0.5%, it is difficult for the nanosheets to form effective overlap, making it impossible to construct a complete labyrinth barrier structure and thermally conductive network. When the content is higher than 5.0%, the viscosity of the paint increases sharply, and the nanosheets are prone to physical aggregation, leading to increased surface roughness of the paint film and the generation of microstructural weaknesses. The online annealing process in the preparation method adopts direct current heating or induction heating. The protective gas pressure filled in the annealing tube is slightly higher than the external atmospheric pressure, forming positive pressure protection to prevent air leakage from causing oxidation of the copper conductor surface, thereby ensuring extremely high interfacial energy between the composite insulation layer and the conductor, and enhancing the adhesion stability of the paint film.

[0027] In this invention, the resin matrix in the composite insulation layer of the enameled wire can be selectively chosen for different application scenarios. For applications requiring extremely high heat resistance, polyamide-imide resin is preferred, as its glass transition temperature is typically above 270 degrees Celsius. For applications requiring good solderability, polyurethane resin containing isocyanate components is selected. Regardless of the resin matrix used, the addition of modified two-dimensional nanosheets further enhances its intrinsic insulation and thermal conductivity limits.

[0028] In the internal microstructure of the composite insulating layer, the orientation of the modified two-dimensional nanosheets depends not only on the shear force of the mold but also on the capillary contraction force generated during the gradient evaporation of the paint solvent. This invention, by precisely controlling the temperature rise slope of the oven, generates radial pressure towards the conductor surface during the curing and shrinkage process of the paint film, further compacting and correcting the parallel alignment of the nanosheets, thereby forming a functional layer with uniform density and extremely high orientation in the final solid paint film.

[0029] In addressing the interfacial compatibility between nanosheets and the resin matrix, this invention selects silane coupling agents with specific long-chain structures. These structures create steric hindrance on the nanosheet surface, preventing secondary agglomeration of the exfoliated nanosheets during paint storage. Simultaneously, the active functional groups at the ends of these coupling agent molecules undergo dehydration condensation reactions with polar groups (such as imino and hydroxyl groups) in the resin matrix during the high-temperature curing stage, forming a robust chemical bridge. This microscopic structural correlation ensures the durability of macroscopic properties and reliability under various environmental cycles.

[0030] In the preparation of the composite insulating layer, the specific process conditions for surface-active modification were designed differently for two-dimensional nanosheets with different chemical properties. For hexagonal boron nitride nanosheets, a silane grafting method based on hydroxylation treatment was used; for reduced graphene oxide, the residual oxygen-containing functional groups on its surface were used for direct silanization reaction. This targeted treatment ensured that different types of nanosheets could achieve optimal dispersion and interfacial bonding strength.

[0031] The drawing and coating processes of the central conductor are carried out on a fully automated continuous production line. In the drawing section, multi-die continuous drawing is employed, using a water-based synthetic lubricant containing extreme pressure additives to reduce the risk of surface scratches during the drawing process, providing a perfect base surface quality for subsequent thin-film coating. The tension control system in the coating section uses a magnetic powder brake and servo motor linkage, with a response time of less than 10 milliseconds. This ensures smooth operation of the wire as it passes through the coating mold and oven at high speed, completely eliminating the risk of uneven film thickness or wire breakage due to tension fluctuations.

[0032] Compared with the prior art, the beneficial effects of the present invention are: 1. The labyrinth effect generated by the orientation and arrangement of two-dimensional nanosheets improves the breakdown voltage of the fine enameled wire and reduces the pinhole rate without increasing the physical thickness of the enamel film, thus resolving the contradiction between thin enamel film and high insulation reliability. At the same time, the thin enamel film design makes the coil winding more compact, improves space utilization, and meets the needs of highly integrated electromagnetic components. 2. By utilizing the high thermal conductivity of two-dimensional nanosheets, an efficient heat conduction path is constructed inside the coating film, which reduces the center temperature rise of the wire during operation, protects the self-adhesive layer from local overheating damage, and improves the overall thermal stability and service life of the coil. 3. The covalent bonding between the modified nanosheets and the resin matrix enhances the mechanical strength and adhesion of the coating film, and improves the tensile and wear resistance of the enameled wire during precision winding. Detailed Implementation

[0033] This invention provides a thin-film, micro-fine, self-adhesive enameled wire and its preparation method. The core of this invention lies in achieving a synergistic improvement in electrical insulation reliability, thermal conductivity, and mechanical adhesion performance at an extremely thin film thickness through physical reconstruction and chemical modification of the insulation layer's microstructure. In practice, the enameled wire consists of a central conductor, a composite insulation layer, and an outer self-adhesive layer from the inside out. The material selection of the central conductor directly determines the wire's basic mechanical strength and conductivity. Typically, high-purity oxygen-free copper wire or copper alloy wire with higher tensile strength is used. The wire diameter is set within the ultra-fine range of 0.010 mm to 0.050 mm according to the precision requirements of microelectronic components.

[0034] The technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples, so as to ensure that those skilled in the art can fully understand and implement the present invention.

[0035] Example 1: Center conductor (oxygen-free copper, wire diameter 0.03 mm, surface roughness Ra 0.03 μm, elongation at break 40%). Composite insulating layer (radial thickness 0.005 mm, polyamide-imide resin as matrix, 3% modified two-dimensional nanosheets, hexagonal boron nitride nanosheets with an aspect ratio of 500 and a layer thickness of 8 nm, silane coupling agent is γ-aminopropyltriethoxysilane). Outer self-adhesive layer (modified polyamide resin, thickness 0.0025mm, softening point 180℃, containing nonionic fluorocarbon surfactant and antistatic agent); Preparation steps: S1: Preparation of functionalized nano paint: 5 parts of hexagonal boron nitride nanosheets are dispersed in 95 parts of N-methylpyrrolidone, 4% silane coupling agent is added, and the mixture is ultrasonicated at 1200W for 6 hours at 50℃; then it is mixed with polyamide imide resin paint and stirred at 3500 rpm for 2 hours. The viscosity at 25℃ is 300 mPa·s. S2: Pretreatment and coating of the center conductor, online annealing of the conductor under nitrogen protection at 450℃, and entry into the coating chamber at a linear speed of 400m / min. The first 5 passes are coated with a high shear force mold (half compression angle of 5 degrees, length-to-diameter ratio of 4:1 in the sizing section), and the last 3 passes are coated with different nanosheet concentrations of paint in layers (1.5% for the inner layer, 4% for the middle layer, and 0.3% for the outer layer). S3: Gradient temperature controlled baking, each coating is baked in an oven (solvent evaporation zone 180℃, pre-curing zone 280℃, deep curing zone 400℃, cooling zone 60℃). S4: Self-adhesive layer coating and winding, after the composite insulation layer cools, self-adhesive layer is dipped in, baked at 150℃, and wound with constant tension of 0.2N.

[0036] Example 2: The center conductor wire diameter is 0.01 mm, and the remaining components and proportions are the same as in Example 1; Preparation steps: Adjust the mold hole size, and the remaining steps are the same as in Example 1.

[0037] Example 3: The center conductor wire diameter is 0.05mm, and the remaining components and proportions are the same as in Example 1; Preparation steps: Adjust the mold hole size, and the remaining steps are the same as in Example 1.

[0038] Example 4: The content of modified two-dimensional nanosheets in the composite insulating layer is 0.5%, and the remaining components and proportions are the same as in Example 1; Preparation steps: Same as in Example 1.

[0039] Example 5: The content of modified two-dimensional nanosheets in the composite insulating layer is 5.0%, and the remaining components and proportions are the same as in Example 1; Preparation steps: Same as in Example 1.

[0040] Example 6: The radial thickness of the composite insulation layer is 0.002 mm, and the remaining components and proportions are the same as in Example 1; Preparation steps: Reduce the number of coating passes, and the remaining steps are the same as in Example 1.

[0041] Example 7: The radial thickness of the composite insulation layer is 0.008 mm, and the remaining components and proportions are the same as in Example 1; Preparation steps: Increase the number of coating passes, and the remaining steps are the same as in Example 1.

[0042] Example 8: Modified two-dimensional nanosheets were replaced with reduced graphene oxide microsheets (carbon-oxygen atom ratio 25:1, specific surface area 600 m²). 2 / g), the remaining components and proportions are the same as in Example 1; Preparation steps: Same as in Example 1.

[0043] Comparative Example 1: The composite insulating layer is pure polyamide-imide resin, without modified two-dimensional nanosheets, and the other components are the same as in Example 1; Preparation steps: The steps related to the preparation of nano-coatings are omitted, and the remaining process parameters and steps are the same as in Example 1.

[0044] Comparative Example 2: Same as Example 1; Preparation steps: A common coating mold was used, and the nanosheets were not oriented by strong shear stress. The remaining process parameters and steps were the same as in Example 1.

[0045] Test method: Insulation performance test: Measure the breakdown voltage and count the number of pinholes per meter; Thermal conductivity testing: The radial thermal conductivity of the composite insulation layer was measured using the laser flare method. Self-adhesive performance test: After winding the coil, heat bond it at 180°C and measure the bonding strength; Mechanical performance testing: Determine the tensile strength and coating adhesion of the enameled wire (scratching test). Thermal stability test: Aging at 180℃ for 1000 hours, and determination of the aging strength retention rate; Dimensional accuracy test: Determine the deviation of the outer diameter of the enameled wire.

[0046] The test data comparisons are shown in Table 1 and Table 2.

[0047] Table 1. Comparison of Breakdown Voltage, Number of Pinholes per Meter, Radial Thermal Conductivity, and Self-Adhesive Strength

[0048] Table 2 Comparison of Strength Retention Rate, Paint Film Adhesion, and Outer Diameter Deviation at 180℃

[0049] Examples 1 to 8 utilize highly oriented modified two-dimensional nanosheets to form a maze structure, extending the electron breakdown path and constructing continuous thermally conductive channels. A strong shearing process ensures the nanosheets are regularly arranged, and a silane coupling agent achieves chemical bonding. Comparative Example 1, lacking nanosheets, exhibits significantly reduced insulation and thermal conductivity. Comparative Example 2, lacking an orientation process, has randomly distributed nanosheets, resulting in the failure of the maze effect and a decline in performance.

[0050] When the center conductor diameter is 0.03mm to 0.05mm, the nanosheet content is 3% to 5%, and the insulation layer thickness is 0.005mm to 0.008mm, the insulation and thermal conductivity are better. Among them, the nanosheet content directly affects the labyrinth density and the integrity of the thermal network, while the insulation layer thickness balances the breakdown voltage and the need for thinness. The two work together to ensure the overall performance of the enameled wire.

[0051] Compared to Comparative Example 1 without nanosheets, the breakdown voltage of the embodiments is increased by more than 94%, the thermal conductivity is increased by more than 333%, and the number of pinholes is reduced by more than 83%; compared to Comparative Example 2 with non-oriented process, the breakdown voltage is increased by more than 79%, the thermal conductivity is increased by more than 160%, and the coating adhesion is increased by more than 67%, meeting the high integration and high power requirements of micro electronic components.

[0052] In summary, this invention achieves simultaneous improvement in insulation, thermal conductivity, and self-adhesion properties under thin enamel films by coupling modified two-dimensional nanosheet orientation and process optimization, solving the core pain points of traditional micro-enameled wires. It is suitable for precision electromagnetic components and has good potential for industrialization.

[0053] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A thin-film, fine, self-adhesive enameled wire, characterized in that, The enameled wire, from the inside out, includes a central conductor, a composite insulation layer covering the outer peripheral surface of the central conductor, and an outer self-adhesive layer covering the outer surface of the composite insulation layer.

2. The thin-film, fine, self-adhesive enameled wire according to claim 1, characterized in that, The composite insulation layer is composed of an insulating resin matrix and modified two-dimensional nanosheets uniformly dispersed in the insulating resin matrix, wherein the mass percentage content of the modified two-dimensional nanosheets in the composite insulation layer is 0.5% to 5.0%.

3. The thin-film, fine, self-adhesive enameled wire according to claim 2, characterized in that, The modified two-dimensional nanosheets are highly oriented within the insulating resin matrix, with the plane of the modified two-dimensional nanosheets forming an angle of less than 5 degrees with the axial direction of the central conductor, and exhibiting a layered, reciprocating maze-like arrangement on the radial cross-section of the composite insulating layer.

4. The thin-film, fine, self-adhesive enameled wire according to claim 1, characterized in that, The center conductor is made of oxygen-free copper wire or high-strength copper alloy wire.

5. The thin-film, fine, self-adhesive enameled wire according to claim 2, characterized in that, The insulating resin matrix is ​​one or more of polyamide-imide resin, polyester-imide resin, or polyurethane resin.

6. The thin-film, fine, self-adhesive enameled wire according to claim 2, characterized in that, The modified two-dimensional nanosheets are formed by surface-active modification of hexagonal boron nitride nanosheets or reduced graphene oxide microsheets.

7. The thin-film, fine, self-adhesive enameled wire according to claim 6, characterized in that, When the modified two-dimensional nanosheet is a hexagonal boron nitride nanosheet, its average aspect ratio is 200 to 800, and the sheet thickness is distributed between 3 nm and 15 nm; when the modified two-dimensional nanosheet is a reduced graphene oxide microsheet, its carbon-oxygen atom ratio is greater than 20:

1.

8. The thin-film, fine, self-adhesive enameled wire according to claim 2, characterized in that, The modified two-dimensional nanosheets have a silane coupling agent molecular layer grafted onto their surface, wherein the silane coupling agent is one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, or vinyltrimethoxysilane.

9. The thin-film, fine, self-adhesive enameled wire according to claim 1, characterized in that, The composite insulation layer is formed by layering nano-coatings of different concentrations from the inside to the outside along the radial direction of the central conductor, including an inner composite insulation layer, a middle composite insulation layer and an outermost composite insulation layer.

10. A thin-film, fine, self-adhesive enameled wire according to claim 9, characterized in that, The inner composite insulating layer contains 1.0% to 2.0% by mass of modified two-dimensional nanosheets; the middle composite insulating layer contains 3.0% to 5.0% by mass of modified two-dimensional nanosheets; and the outermost composite insulating layer uses pure resin paint or paint with a modified two-dimensional nanosheet content of less than 0.5%.

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