Insulated electric wire, method for manufacturing the same, coil, and electronic / electrical device

Abstract

This invention discloses an insulated wire, its preparation method, a coil, and electronic / electrical equipment. The insulated wire includes a conductor, an adhesive layer covering the conductor, and a resin layer covering the adhesive layer. The resin layer is obtained by melt extrusion molding of a resin composition comprising polyetheretherketone (PEEK) and polyetherketoneketone (PEKK), wherein the mass ratio of PEEK to PEKK is 5–95:95–5, and the crystallinity of the resin layer is ≤20%. This invention significantly enhances interlayer adhesion and peel resistance by setting an adhesive layer between the conductor and the resin layer; by using a blend of PEEK and PEKK and controlling the low crystallinity structure, it ensures excellent heat resistance and chemical resistance of the insulation layer while imparting good flexibility and electrical reliability to the wire after bending. This insulated wire is particularly suitable for the manufacture of small inductors and other electronic components with stringent requirements for bending, electroplating, and soldering processes.

Description

Technical Field

[0001] This invention relates to the field of wire and cable manufacturing technology, specifically to an insulated wire and its preparation method, a coil, and electronic / electrical equipment. Background Technology

[0002] In the manufacturing of inductors, especially through-hole inductors, the fabrication of the inductor pin terminals is one of the key technological steps. The conventional pin terminal manufacturing process mainly includes three core steps: "enamel removal—electroplating—soldering." Specifically, the insulation layer of the insulated wires needs to be removed at the pin terminals to expose the conductors for subsequent electroplating and soldering. Enamel removal methods mainly include high-energy methods such as laser / plasma removal, as well as mechanical methods such as mechanical scraping.

[0003] Both high-energy paint stripping and mechanical paint stripping have inherent defects, easily introducing damage or stress concentration at the interface between the insulation layer and the conductor: High-energy paint removal: If the energy is not properly controlled, it may overheat and damage the microstructure of the conductor surface, reducing its mechanical and electrical properties.

[0004] Mechanical paint removal: If the force applied is uneven or excessive, local stress concentration points can easily form on the conductor surface.

[0005] In addition, the wires often need to be bent during the PIN end forming process, which further exacerbates the stress concentration effect mentioned above.

[0006] In this situation, if the initial adhesion between the insulation layer and the conductor is insufficient, localized interfacial peeling is highly likely to occur in areas of stress concentration, leading to insulation layer warping. During the subsequent electroplating process, the plating solution may seep into the peeling gaps and solidify, exacerbating the warping. In the final soldering stage, high-temperature thermal stress amplifies the tendency for interfacial peeling, potentially causing large-area detachment of the insulation layer, or even cracking of the electroplated layer. Ultimately, this results in a series of reliability issues, including poor soldering (cold solder joints), decreased conductivity, and deterioration of environmental corrosion resistance.

[0007] To improve the adhesion and processability of the insulation layer, existing technologies typically employ the following methods: Optimize paint removal process parameters: such as adjusting laser power or mechanical pressure, but this method has a narrow control window and is easily affected by material batches and operational fluctuations, and cannot fundamentally solve the problem of insufficient interfacial adhesion.

[0008] Using adhesion promoters or primers: Adding an adhesive layer between the conductor and the insulation layer can improve adhesion, but if the insulation layer itself has poor flexibility, insufficient heat resistance or chemical resistance, it may still peel off under subsequent bending, electroplating or high-temperature soldering.

[0009] High-performance engineering plastics such as PEEK are used as the insulation layer. Although they have excellent heat resistance and chemical stability, pure PEEK insulation layer has high crystallinity and insufficient flexibility. It is prone to brittleness under bending and thermal shock. In addition, the direct adhesion between it and the metal conductor often does not meet the stringent process requirements of the PIN end.

[0010] Therefore, existing technologies still lack an insulated wire that can maintain excellent flexibility and adhesion under bending and high temperature, and can withstand the corrosion of electroplating solution and the thermal stress of solder, making it difficult to meet the needs of manufacturing high-reliability small inductor pin ends. Summary of the Invention

[0011] This application aims to overcome the shortcomings of existing insulated wires used in the manufacture of small inductor pin terminals in terms of adhesion, flexibility, and resistance to chemical / thermal stress. It provides an insulated wire, its preparation method, coil, and electronic / electrical equipment that combine excellent interface adhesion, low crystallinity, and good resistance to electroplating solutions and solder thermal shock. The core of this application lies in the synergistic control of a composite insulation structure design of an "adhesive layer-low crystallinity resin layer" and the resin component-cooling process. This ensures strong adhesion and peel resistance between the insulation layer and the conductor while achieving high flexibility and low crystallinity of the insulation layer itself. This simultaneously solves the process reliability problems encountered in the entire "paint removal-bending-electroplating-soldering" process of pin terminal manufacturing, such as interface peeling, warpage cracking, and corrosion degradation. This provides key material support for the long-term stable operation of high-density, high-reliability small inductors and electronic devices.

[0012] To address the aforementioned problems, a first aspect of the present invention provides an insulated wire, the insulated wire comprising: a conductor; an adhesive layer covering the outer periphery of the conductor; and a resin layer covering the outer periphery of the adhesive layer; wherein the adhesive layer is formed by curing an adhesive; the resin layer is obtained by melt extrusion molding of a modified resin; the modified resin comprises polyetheretherketone resin (PEEK) and polyetherketoneketone resin (PEKK), wherein the mass ratio of PEEK to PEKK is 5–95:95–5, and the crystallinity of the resin layer is ≤20%.

[0013] This application provides an insulated wire, the core of which lies in the specific composite structure design and material ratio of the conductor, adhesive layer, and resin layer. The resin layer is formed in one step on the outer periphery of the adhesive layer using a modified resin containing PEEK and PEKK through a melt extrusion process; wherein the mass ratio of PEEK to PEKK is 5-95:95-5, and the crystallinity of the resin layer is controlled to be less than 20%. Through the synergistic effect of the adhesive layer and the low-crystallinity resin layer, a strong and durable interfacial bond is established between the resin layer and the conductor, while simultaneously endowing the insulation layer with excellent flexibility and heat / chemical stability. Therefore, under harsh process conditions such as wire bending, paint removal, electroplating, and soldering, it effectively inhibits insulation layer peeling, warping, and performance degradation, ensuring the structural integrity and long-term reliability of electronic components such as inductor pin terminals.

[0014] Furthermore, the modified resin has a melt flow rate ≥8 g / 10 min at 400°C and 2.16 kg load, and the melt flow rate is determined according to ISO 1133 standard.

[0015] Furthermore, the total thickness of the adhesive layer and the resin layer is 5 μm to 100 μm.

[0016] Furthermore, the conductor is at least one of copper, aluminum, copper alloy, or aluminum alloy.

[0017] Furthermore, the adhesive comprises an organic solvent, a polyamide-imide resin, and a PEEK nanopowder material.

[0018] According to another aspect of the present invention, the present invention also provides a method for preparing an insulated wire, for preparing the insulated wire of the above-mentioned technical solution, the preparation method comprising the following steps: Step S1, coating and curing an adhesive on the outside of a conductor to form an adhesive layer, thereby obtaining a conductor with an adhesive layer; Step S2, uniformly mixing polyetheretherketone resin particles and polyetherketoneketone resin particles and then granulating them through an extruder to obtain modified resin particles, and then melt-extruding the obtained modified resin particles through an extruder onto the surface of a preheated conductor with an adhesive layer to form a resin layer; Step S3, rapidly cooling the conductor coated with the resin layer in step S2 to obtain the insulated wire.

[0019] According to another aspect of the invention, the invention also provides a coil comprising the insulated wire described in the invention.

[0020] According to another aspect of the invention, the invention also provides an electronic / electrical device comprising the coil described herein.

[0021] The above-described technical solution of the present invention has the following beneficial technical effects: 1. By setting a dedicated adhesive layer between the conductor and the resin layer, a strong chemical and physical bonding interface is established between the two. This structure can effectively resist the local stress generated during paint stripping (especially mechanical paint stripping) and the thermal stress generated at the high temperature of subsequent soldering, thereby fundamentally preventing warping or peeling between the insulation layer and the conductor and ensuring the structural integrity of the PIN end during manufacturing.

[0022] 2. By blending PEEK and PEKK at a specific mass ratio (5–95:95–5) and employing a rapid cooling process after extrusion, the crystallinity of the resin layer is effectively controlled below 20%. This low crystallinity imparts superior molecular chain mobility to the resin layer, resulting in a significant improvement in the overall flexibility of the insulated wire. During inductor winding and PIN end bending, this low-crystallinity resin layer better adapts to deformation and is less prone to brittleness, thus maintaining a very high insulation breakdown voltage (BDV) retention rate after bending, ensuring the final insulation reliability of the product.

[0023] 3. The PEEK / PEKK mixed resin system exhibits a high melt flow rate (MFR), indicating its excellent processing fluidity. This allows the resin to uniformly and smoothly coat the preheated conductor adhesive layer during melt extrusion coating, forming a dense insulating layer of uniform thickness and free of defects, thus improving production efficiency and product consistency.

[0024] 4. Both PEEK and PEKK are high-performance, high-temperature resistant engineering plastics. Their blended resin layers inherit excellent chemical corrosion resistance, resisting the erosion of acidic substances in electroplating solutions and preventing performance degradation due to swelling or deterioration of the insulation layer. Simultaneously, the high heat resistance of this material system ensures that it will not soften, deform, or decompose at the high temperatures of soldering, maintaining the dimensional stability and dielectric strength of the insulation layer.

[0025] In summary, the three core methods in this application – "adhesive layer," "PEEK / PEKK blend modification," and "rapid cooling process" – work synergistically to systematically optimize interface bonding, bulk material properties, and microstructure. The technical effects directly and clearly address the key technical problems raised in the background technology, such as film warping, decreased insulation after bending, and insufficient resistance to thermal shock from electroplating solutions and solder. Ultimately, it achieves a comprehensive performance breakthrough in insulated wires in terms of high flexibility, strong adhesion, and resistance to harsh processes, providing crucial material support for the manufacture of miniaturized, high-reliability inductor devices. Attached Figure Description

[0026] Figure 1 This is a cross-sectional structural diagram of an insulated wire according to an embodiment of the present invention; Figure label: 1: Conductor; 2: Adhesive layer; 3: Resin layer. Detailed Implementation

[0027] 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 and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0028] To address the problems of easy peeling and warping of the insulation layer, insufficient flexibility, and poor resistance to thermal shock from electroplating solutions and solder in existing insulated wires used for inductor pin terminals, this invention proposes an insulated wire that achieves a synergistic improvement in adhesion, flexibility, and environmental resistance by sequentially setting an adhesive layer and a specific resin layer around the conductor. The resin layer is formed by melt extrusion and rapid cooling of a blend of PEEK and PEKK in a mass ratio of 5–95:95–5, with its crystallinity controlled below 20%. This structure ensures strong adhesion and peel resistance between the insulation layer and the conductor through the adhesive layer (such as a system containing organic solvents, polyamide-imide resin (PAI), and PEEK nanopowder); simultaneously, the low-crystallinity PEEK / PEKK blend resin layer endows the wire with excellent bending flexibility and high insulation retention, and it can withstand the corrosion of electroplating solutions and the high temperatures of solder. This invention fundamentally solves the technical problem of easy warping and peeling of the coating film during bending, paint removal, electroplating and soldering by the synergistic design of the structure and process of "adhesive layer interface enhancement" and "low crystallinity resin layer", providing key basic materials for the manufacture of miniaturized and high-reliability inductor devices.

[0029] The following is combined with Figure 1 The insulated wires, their preparation methods, coils, and electronic / electrical devices provided by this invention are described.

[0030] Figure 1 This is a cross-sectional structural diagram of an insulated wire according to an embodiment of the present invention.

[0031] like Figure 1As shown, this embodiment provides an insulated wire, which includes a conductor 1 at the center, an adhesive layer 2 sequentially covering the outer periphery of the conductor 1, and a resin layer 3 covering the outer periphery of the adhesive layer 2. The adhesive layer 2 is formed by coating and curing an adhesive (such as a system containing organic solvent, polyamide-imide resin (PAI), and PEEK nanopowder material). The resin layer 3 is formed in one step by a modified resin through a melt extrusion process. The modified resin is a mixture of PEEK and PEKK in a mass ratio of 5-95:95-5. In the production process, the conductor 1 is first preheated and coated with adhesive, and then dried and cured to form a dense adhesive layer 2. Subsequently, PEEK and PEKK resin particles are mixed evenly and melt extruded, directly coating the surface of the preheated adhesive layer 2. Then, the coated wire is rapidly immersed in a cooling medium (such as a water tank) for rapid cooling, so that the resin temperature is lowered below the crystallization temperature (the resin does not have time to crystallize), thereby obtaining a resin layer 3 with a crystallinity ≤20%.

[0032] This structural design establishes a strong and durable chemical-physical bonding interface between the conductor 1 and the resin layer 3 through the adhesive layer 2, effectively resisting mechanical and thermal stresses generated during bending, paint removal, and soldering, fundamentally preventing insulation warping or peeling. Simultaneously, the use of a PEEK / PEKK blend system combined with a rapid cooling process results in a low-crystallinity microstructure in the resin layer 3, endowing the insulated wire with excellent flexibility and electrical insulation retention after bending, and enabling it to withstand the chemical corrosion of electroplating solutions and the impact of high-temperature soldering. Through these methods, the insulated wire of this embodiment achieves synergistic optimization of high adhesion, high flexibility, and high environmental reliability while simplifying the process, making it particularly suitable for the manufacture of electronic components such as small inductor pin terminals with stringent requirements for process compatibility and long-term reliability.

[0033] Preferably, the melt flow rate of the resin composition at 400°C and a load of 2.16 kg is ≥8 g / 10 min, and the melt flow rate is measured according to ISO 1133 standard. This preferred feature ensures that the resin has good flowability and processing window during melt extrusion, which is beneficial for forming a resin layer with uniform thickness, dense surface and no defects, thereby improving product consistency and production efficiency, and ensuring the reliability of insulation performance.

[0034] Preferably, the total thickness of the adhesive layer and the resin layer is between 5 μm and 100 μm. This preferred thickness range ensures that the insulated wire has sufficient electrical insulation performance and mechanical protection while maximizing the overall flexibility and fine wire diameter of the wire, which is beneficial for its winding, bending and spatial arrangement in high-density, miniaturized electronic devices (such as miniature inductors).

[0035] Optionally, the conductor is at least one of copper, aluminum, copper alloy, or aluminum alloy. These conductor materials possess excellent conductivity, ductility, and process maturity, enabling them to form a stable interface with the adhesive layer. While ensuring low resistance transmission of the wire, they also meet the requirements of subsequent processing such as bending and welding, exhibiting wide applicability and economy.

[0036] Preferably, the adhesive comprises an organic solvent, a polyamide-imide resin, and PEEK nanoparticles. This preferred formulation utilizes the dual affinity of the polyamide-imide resin for both metal conductors and PEEK-based resins to construct a strong and tough adhesive interface. The added PEEK nanoparticles further enhance the chemical compatibility and physical interlocking between the adhesive layer and the surrounding resin layer, thereby significantly improving interlayer adhesion and peel resistance, effectively preventing interface failure in subsequent demanding processes.

[0037] This embodiment also provides a method for preparing an insulated wire, which includes the following steps: Step S1: Apply and cure adhesive to the outside of the conductor to form an adhesive layer, thus obtaining a conductor with an adhesive layer.

[0038] In some embodiments, this step is used for conductor pretreatment and adhesive layer formation, and its specific operation is as follows: (1) The adhesive containing organic solvent, polyamide-imide resin and PEEK nanopowder material is formulated to a suitable coating viscosity; (2) The conductor is surface cleaned and preheated, wherein the conductor is at least one of copper, aluminum, copper alloy or aluminum alloy; (3) Apply the adhesive evenly and repeatedly to the preheated conductor surface by means of dip coating, spray coating or roller coating; (4) Perform step-by-step heating and curing at a set temperature to allow the solvent to evaporate and the resin to cross-link and cure, forming a continuous and dense adhesive layer on the surface of the conductor, thus obtaining a preheated conductor with an adhesive layer.

[0039] Step S2: After uniformly mixing polyetheretherketone resin particles and polyetherketoneketone resin particles, the mixture is granulated by extruder to obtain modified resin particles. The modified resin particles are then melt-extruded by extruder onto the preheated surface of a conductor with an adhesive layer to form a resin layer.

[0040] In some embodiments, this step is used for melt extrusion and coating of the resin composition, and its specific operation is as follows: (1) PEEK resin particles and PEKK resin particles are premixed evenly in a mixer at a mass ratio of 5-95:95-5 to obtain a resin mixture. (2) The resin mixture is added to a twin-screw extruder for extrusion granulation to obtain modified resin particles; (3) The modified resin particles are melt-plasticized in the range of 380℃~420℃ to obtain molten resin; (4) Guide the conductor with adhesive layer obtained in step S1 to the die of the extruder and keep its preheating temperature within the range of ±30°C of the resin melt temperature. (5) The molten resin is extruded through an annular die to tightly coat the outer periphery of the conductor adhesive layer, forming a resin layer.

[0041] In some embodiments, the total thickness of the adhesive layer formed in step S1 and the resin layer formed in step S2 is 5 μm to 100 μm.

[0042] Step S3: Rapidly cool the conductor coated with resin layer from step S2 to obtain an insulated wire.

[0043] In some embodiments, this step is used for rapid cooling and shaping, and its specific operation is as follows: (1) The conductor that leaves the extrusion die and is covered with a resin layer is directly introduced into the cooling water tank through the shortest path; (2) Control the cooling water temperature within the range of 0℃ to 30℃ so that the resin layer drops rapidly below its glass transition temperature after leaving the die, thereby inhibiting the crystallization process; (3) After cooling and drying, the wire is wound up to obtain an insulated wire with a resin layer crystallinity of less than 20%.

[0044] This preparation method, through sequential steps of adhesive layer curing, resin layer melting and coating, and rapid cooling, simplifies the process while ensuring a strong bond between the adhesive layer, conductor, and resin layer, and effectively controls the crystal structure of the resin layer. This results in a synergistic improvement in the adhesion, flexibility, and environmental reliability of the insulated wire.

[0045] The present invention also provides a coil comprising the insulated wire described herein.

[0046] The present invention also provides an electronic / electrical device comprising the coil described herein.

[0047] For details regarding the principle, implementation, and beneficial effects of this insulated wire, as well as the process flow and advantages of its preparation method, please refer to the preceding text. Figure 1 The descriptions of insulated wires and their manufacturing methods shown are not repeated here.

[0048] The insulated wires provided in this application are further described below with reference to specific embodiments and performance test data. Unless otherwise specified, all raw materials used are commercially available. In the embodiments and comparative examples, the conductor size is a 0.2mm × 2.0mm rectangular copper wire, and the total thickness of the target insulation layer (adhesive layer + resin layer) is 50μm. The tests mainly focus on heat preservation time, resin layer crystallinity, and insulation breakdown voltage (BDV) tests before and after soaking in salt water.

[0049] The following are the specific formulations, process parameters, and performance test results of Examples 1 to 4 and Comparative Examples 1 to 3. For detailed data, please refer to Table 1.

[0050]

[0051] The specific test methods and evaluation criteria involved in the above embodiments in Table 1 are as follows: (1) Insulation time refers to the insulation time of the extruder after extrusion into the insulation box at a temperature of 260°C or higher; no insulation means that the extruder enters the cold water tank directly for cooling after extrusion.

[0052] (2) Resin layer crystallinity test Differential scanning calorimetry (DSC) was used for testing, and a crystallinity of less than 20% was used as the criterion for acceptance.

[0053] (3) Insulation breakdown voltage (BDV) test and environmental reliability evaluation The insulation breakdown voltage test was performed using the breakdown voltage test method provided in IEC 60851-5:2019 Test Method 13.

[0054] Specific steps: Remove the outer layer from one end of the insulated wire, tightly wind it 10 turns around a φ1mm diameter core rod, and then place it in a container containing Φ0.8mm metal beads. Ensure the insulated wire end extends sufficiently to prevent flashover. Apply a test voltage between the conductor and the metal beads, increasing the voltage at a rate of 500V / s, with the leakage current set to 5mA. Perform the test 5 times and take the average voltage as the insulation breakdown voltage.

[0055] Environmental reliability simulation test: After the wound sample is immersed in salt water for 5 days, the above BDV test is performed again.

[0056] Evaluation criteria: Calculate the BDV retention rate after soaking in saline solution (BDV after soaking in saline solution / BDV before soaking in saline solution × 100%), and a retention rate of ≥90% is considered acceptable.

[0057] Based on the data in Table 1, the analysis is as follows: The effectiveness of the technical solution in this application (Examples 1 to 4): All examples meet the requirement of crystallinity ≤20%, and the BDV retention rate is higher than 90% (actually 91.98%-98.91%), all of which are qualified. This shows that by using the technical solution of "setting an adhesive layer", "using a PEEK / PEKK blend system" and "rapid cooling after extrusion (no heat preservation or short-term heat preservation)", it is possible to successfully prepare insulated wires that have both low crystallinity (high flexibility) and excellent environmental reliability (high adhesion and corrosion resistance).

[0058] Necessity of the adhesive layer (Comparative Example 1): Compared with Example 1, Comparative Example 1 omitted the adhesive layer, while other conditions remained the same. Its BDV retention rate dropped significantly to 74.75% (unacceptable). This demonstrates that the adhesive layer is a key structure to ensure that the insulation layer adheres firmly to the conductor and does not deteriorate in performance under harsh environments. The lack of an adhesive layer will directly lead to a significant reduction in environmental reliability.

[0059] The necessity of PEEK / PEKK blending (Comparative Example 2): Compared with Example 2, Comparative Example 2 used pure PEEK resin. Under the same short-term heat preservation conditions (1.5s), its resin layer crystallinity (25%) was higher than that of Examples 1 and 2 (13% and 20%), and its BDV retention rate (81.99%) did not reach the 90% acceptable threshold. This proves that the introduction of PEKK effectively inhibits the crystallization ability of the resin, which is an important means to achieve low crystallinity, thereby obtaining higher flexibility and better environmental reliability.

[0060] The key role of rapid cooling process (Comparative Example 3): Compared with Examples 1 and 2, Comparative Example 3, under the same formulation, extended the holding time to 4 seconds, resulting in a sharp increase in resin layer crystallinity to 30%, while the BDV retention rate dropped significantly to 73.39% (unacceptable). This contrasts sharply with Examples 1 (no holding time, crystallinity 13%, retention rate 98.19%) and 2 (holding time 1.5s, crystallinity 20%, retention rate 91.98%). This clearly demonstrates that controlling the cooling rate after leaving the extruder (i.e., shortening the high-temperature residence time) is a core process condition for obtaining a low-crystallinity resin layer, thereby ensuring the final performance of the wire. Excessive holding time will cause the resin to fully crystallize, impairing flexibility and interfacial stability.

[0061] Therefore, the technical solution provided in this application, through the synergistic effect of "adhesive layer interface strengthening", "PEEK / PEKK blending modification" and "rapid cooling process control", can prepare insulated wires with low crystallinity, good flexibility, and can still maintain extremely high insulation performance after being eroded by simulated electroplating solution. It successfully solves the problems of varnish warping, peeling and insufficient environmental reliability that are easy to occur in the manufacturing of inductor PIN ends of traditional insulated wires.

[0062] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. An insulated wire, characterized in that, include: conductor; An adhesive layer covering the outer periphery of the conductor; A resin layer covering the outer periphery of the adhesive layer; The adhesive layer is formed by curing an adhesive; the resin layer is obtained by melt extrusion molding of modified resin; the modified resin includes polyetheretherketone resin and polyetherketoneketone resin, the mass ratio of polyetheretherketone resin and polyetherketoneketone resin is 5-95:95-5, and the crystallinity of the resin layer is ≤20%.

2. The insulated wire according to claim 1, characterized in that, The modified resin has a melt flow rate ≥8 g / 10 min at 400℃ and 2.16 kg load, and the melt flow rate is determined according to ISO 1133 standard.

3. The insulated wire according to claim 1, characterized in that, The total thickness of the adhesive layer and the resin layer is 5 μm to 100 μm.

4. The insulated wire according to any one of claims 1-3, characterized in that, The conductor is at least one of copper, aluminum, copper alloy, or aluminum alloy.

5. The insulated wire according to any one of claims 1-3, characterized in that, The adhesive comprises an organic solvent, a polyamide-imide resin, and a PEEK nanopowder material.

6. A method for preparing an insulated wire, used to prepare the insulated wire according to any one of claims 1-5, characterized in that, Includes the following steps: Step S1: Apply and cure adhesive to the outside of the conductor to form an adhesive layer, thereby obtaining a conductor with an adhesive layer; Step S2: After uniformly mixing polyetheretherketone resin particles and polyetherketoneketone resin particles, the mixture is granulated by a twin-screw extruder to obtain modified resin particles. The modified resin particles are then melt-extruded by an extruder onto the surface of a preheated conductor with an adhesive layer to form a resin layer. Step S3: The conductor covered with the resin layer in step S2 is rapidly cooled to obtain the insulated wire.

7. A coil, characterized in that, It comprises an insulated wire made by any one of claims 1-5 or an insulated wire made by the method for making an insulated wire as described in claim 6.

8. An electronic / electrical device, characterized in that, It includes the coil as described in claim 7.

Images