Composite wire rod and processing technology thereof
By introducing a transition layer and stepped heat treatment into the composite wire, the problem of insufficient bonding between the core material and the cladding layer is solved, achieving performance stability and dimensional accuracy of the wire under extreme environments, making it suitable for high-end electronics and aerospace fields.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-11
- Publication Date
- 2026-03-20
AI Technical Summary
Existing composite wires suffer from insufficient bonding between the core and the cladding, poor dimensional accuracy, and inadequate high and low temperature resistance and bending resistance to meet the demands of high-end applications. Furthermore, their manufacturing processes are complex and costly.
A transition layer is formed on the surface of the core material by electrostatic spraying or solution impregnation. A polymer layer is then coated using a micro extruder, and a stepped heat treatment is applied to form a good bond between the core material and the coating layer, thereby controlling the dimensional accuracy and performance stability of the wire.
It improves the bonding strength between the core material and the cladding layer, ensuring stable performance of the wire under extreme temperature and frequent bending conditions, meeting the stringent requirements of the electronics, electrical and aerospace fields, and extending its service life.
Smart Images
Figure CN121709331A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of composite wire processing technology, specifically to a composite wire and its processing technology. Background Technology
[0002] With the rapid development of electronics, electrical engineering, aerospace, and other fields, the performance requirements for wires are becoming increasingly stringent. In the electronics field, miniaturized, high-performance electronic devices are constantly emerging, such as smartphones and wearable devices. This requires wires with finer diameters to fit into compact internal spaces, while ensuring good conductivity to reduce energy loss and improve device efficiency and lifespan. In the aerospace field, wires need to operate under extreme environmental conditions, such as high temperatures, low temperatures, and high radiation. This requires wires to have excellent resistance to high and low temperatures, chemical stability, and mechanical strength to ensure reliable operation in complex and harsh environments.
[0003] Limitations of single-material wires: While traditional single-metal wires possess good conductivity, they suffer from significant deficiencies in corrosion resistance and insulation. For example, copper wires are prone to oxidation and corrosion in humid or corrosive environments, leading to increased resistance and affecting the stability of signal and power transmission, potentially even causing safety accidents. While single-polymer wires offer good insulation and corrosion resistance, their extremely poor conductivity fails to meet the basic requirements of power and signal transmission.
[0004] Shortcomings in the manufacturing process of composite wires: Although some composite wires are available on the market, their manufacturing processes have numerous problems. Some composite wires lack an effective transition layer between the core and the cladding, resulting in weak bonding and a tendency for the cladding to peel off during use, severely impacting the wire's performance and lifespan. Furthermore, some manufacturing processes have poor dimensional accuracy control, leading to significant diameter deviations. This not only affects the installation and use of the wire in precision equipment but may also cause unstable electrical performance. Moreover, composite wires manufactured using existing processes struggle to meet the demands of high-end applications in terms of high and low temperature resistance and bending resistance. Under extreme temperature conditions or after repeated bending, the wires are prone to performance degradation or even damage.
[0005] Although some studies have improved the fabrication process of composite wires, certain shortcomings remain. For example, some improved processes have increased the complexity and cost of the fabrication process without significantly improving the overall performance of the wire; some processes, while improving bonding strength, have negatively impacted other properties of the wire, such as conductivity and resistance to high and low temperatures. Therefore, developing a processing technology that can comprehensively improve the various properties of composite wires while being simple and cost-effective is of significant practical importance. Summary of the Invention
[0006] To address the shortcomings of existing technologies, this invention provides a composite wire and its processing technology, which has advantages such as good conductivity, strong comprehensive performance, long service life and high production quality, thus solving the problems mentioned in the background technology.
[0007] To achieve the above objectives, the present invention provides the following technical solution:
[0008] A processing technology for composite wires includes the following steps:
[0009] S1. Core material pretreatment: The metal core material is cleaned and roughened.
[0010] S2. Transition layer preparation: A transition layer is formed on the surface of the core material by electrostatic spraying or solution impregnation.
[0011] S3, Coating Layer Extrusion: A polymer layer is coated onto the outer surface of the transition layer using a micro extruder;
[0012] S4. Online heat treatment: The coated wire is subjected to stepped heat treatment;
[0013] S5. Sizing and Cooling: The outer diameter of the wire is precisely controlled by a sizing mold, and then cooled and shaped.
[0014] S6. Winding Inspection: Wind the wire and perform performance testing.
[0015] Furthermore, the surface cleaning in S1 employs a combination of alkaline degreasing and acid pickling activation;
[0016] The roughening treatment in S1 is performed by sandblasting or chemical etching, and the surface roughness Ra is controlled between 1.0 and 3.0 μm.
[0017] Furthermore, the voltage for electrostatic spraying in S2 is 30-60kV, and the spraying thickness is controlled by the wire feeding speed and spraying time.
[0018] The solution impregnation in S2 adopts a multiple impregnation-drying process, with the number of impregnations being 2-4 times.
[0019] Furthermore, the extrusion temperature of the micro extruder in S3 is determined according to the polymer material, and the temperature control accuracy is ±2℃;
[0020] The extrusion pressure in S3 is 10-50 MPa, and the extrusion speed is 5-20 m / min.
[0021] Furthermore, the stepped heating process in S4 includes three stages:
[0022] First stage: 80-120℃, keep warm for 5-10 minutes to remove residual solvent;
[0023] Second stage: 150-250℃, keep warm for 3-8 minutes to promote interface fusion;
[0024] Third stage: 280-350℃, hold for 1-3 minutes to complete crystallization.
[0025] Another technical problem to be solved by the present invention is to provide a composite wire, comprising a core material and a coating layer covering the outer surface of the core material;
[0026] The core material is a metallic material, and the covering layer is a polymer material.
[0027] A transition layer is provided between the core material and the covering layer, and the transition layer is a composite material of metal and polymer.
[0028] Furthermore, the core material is copper or a copper alloy with a conductivity ≥58 MS / m; the diameter of the core material is 0.05-2.0 mm.
[0029] Furthermore, the coating layer is one of polytetrafluoroethylene, polyimide, or polyetheretherketone; the thickness of the coating layer is 0.01-0.2 mm.
[0030] Furthermore, the transition layer is a polymer composite material containing metal powder, with the metal powder content being 30-60 wt%; the thickness of the transition layer is 0.005-0.05 mm.
[0031] Furthermore, the dimensional change rate of the composite wire is ≤0.5% within a temperature range of -50℃ to 200℃; the bending resistance of the composite wire is ≥5000 cycles (R=10d).
[0032] Compared with the prior art, the present invention provides a composite wire and its processing technology, which has the following beneficial effects:
[0033] 1. This composite wire and its processing technology form a transition layer on the core surface using electrostatic spraying or solution impregnation. Under a voltage of 30-60kV, the metal-polymer composite material can be uniformly adhered to the core surface. The spraying thickness is precisely controlled by the wire feeding speed and spraying time. The solution impregnation uses a multiple impregnation-drying process, with 2-4 impregnations, to ensure good mechanical interlocking and chemical bonding between the transition layer and the core material. This greatly enhances the bonding force between the core material and the cladding layer, effectively avoids the problem of cladding layer peeling off, improves the reliability and service life of the wire, and achieves the advantage of long service life.
[0034] 2. The composite wire and its processing technology, through the extrusion step of the coating layer, the extrusion temperature of the micro extruder is determined according to the polymer material, with a temperature control accuracy of ±2℃, an extrusion pressure of 10-50MPa, and an extrusion speed of 5-20m / min, so that the thickness of the coating layer is uniform. Combined with the precise control of the wire outer diameter through the sizing die in the sizing and cooling step, it is possible to produce composite wires with extremely high dimensional accuracy and minimal diameter deviation, which meets the strict requirements of precision equipment for wire dimensions, ensures the stability and electrical performance consistency of the wire during installation and use, and achieves the advantage of high production quality.
[0035] 3. The composite wire and its processing technology: The core material of this composite wire is copper or copper alloy, with a conductivity ≥58MS / m, which can ensure efficient power transmission and signal transmission, meet the strict requirements of electronic and electrical fields for the conductivity performance of wires, reduce energy loss, improve the working efficiency of equipment, and achieve the advantage of good conductivity.
[0036] 4. The composite wire and its processing technology produce a composite wire with a dimensional change rate of ≤0.5% within a temperature range of -50℃ to 200℃. This allows it to maintain stable dimensions and performance under extreme temperature environments, making it suitable for fields with extremely high temperature adaptability requirements, such as aerospace and polar exploration. The composite wire has a bending resistance of ≥5000 cycles (R=10d), maintaining good performance even under frequent bending conditions, and is less prone to breakage or performance degradation, thus improving the reliability and service life of the wire. The sheathing layer uses a high-molecular polymer material with excellent insulation and corrosion resistance, effectively protecting the core material from external environmental influences and ensuring safe and reliable operation of the wire in harsh environments such as humidity and corrosiveness, achieving the advantage of strong comprehensive performance. Attached Figure Description
[0037] Figure 1 This is a flowchart of a composite wire processing technology proposed in this invention;
[0038] Figure 2 This is a schematic diagram of the structure of a composite wire proposed in this invention.
[0039] In the diagram: 1. Core material; 2. Covering layer; 3. Transition layer. Detailed Implementation
[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0041] Example 1 (Composite wire for aerospace wiring harnesses):
[0042] Please see Figures 1 to 2 This embodiment provides a composite wire for aerospace wiring harnesses, comprising a copper alloy core 1, a transition layer 3, and a polyimide coating layer 2.
[0043] The composite wire in this embodiment has a conductivity of ≥58 MS / m, which can ensure efficient power transmission and signal transmission, meet the strict requirements of electronic and electrical fields for the conductivity of wires, reduce energy loss, improve the working efficiency of equipment, and achieve the advantage of good conductivity.
[0044] The composite wire in this embodiment exhibits a dimensional change rate of ≤0.5% within a temperature range of -50℃ to 200℃, maintaining stable dimensions and performance under extreme temperature conditions. This makes it suitable for fields with extremely high temperature adaptability requirements, such as aerospace and polar exploration. The composite wire withstands ≥5000 bending cycles (R=10d), maintaining good performance even under frequent bending scenarios, and is less prone to breakage or performance degradation, thus improving the wire's reliability and service life. The sheathing layer uses a high-molecular polymer material with excellent insulation and corrosion resistance, effectively protecting the core material from external environmental influences and ensuring safe and reliable operation of the wire in harsh environments such as humidity and corrosiveness, achieving a high overall performance advantage.
[0045] This embodiment provides a processing technology for composite wires, including the following steps:
[0046] S1. Core material pretreatment:
[0047] A copper alloy wire with a diameter of 0.2 mm and a conductivity of 60 MS / m was selected as the core material.
[0048] Surface cleaning: First, immerse the core material in an alkaline degreasing solution (mainly composed of sodium hydroxide and sodium carbonate, concentration 50g / L) at 60℃ for 5 minutes to remove surface oil; then rinse thoroughly with deionized water. Subsequently, immerse it in a 10% dilute sulfuric acid solution for acid pickling and activation for 2 minutes to further remove the oxide layer and activate the surface, and finally rinse thoroughly with deionized water until neutral.
[0049] Roughening treatment: The cleaned core material was roughened using a sandblasting process with 200-mesh quartz sand, compressed air pressure of 0.5 MPa, and a sandblasting time of 30 seconds. After treatment, the surface roughness Ra was measured to be 2.0 μm using a surface profilometer.
[0050] S2. Transition layer preparation:
[0051] The transition layer was prepared using a solution impregnation method.
[0052] Preparation of transition layer solution: Copper powder with an average particle size of 5 μm (40 wt%) is uniformly dispersed in N-methylpyrrolidone (NMP) solution of polyamic acid (precursor of polyimide).
[0053] The pretreated core material is passed through an impregnation tank containing the above solution at a constant speed (2 m / min) to ensure complete surface wetting. It then enters a drying tunnel and is dried at 120°C for 3 minutes to allow the solvent to evaporate and form a preliminary film. This "impregnation-drying" process is repeated three times, ultimately forming a dense, uniform transition layer on the core material surface with a thickness of approximately 0.02 mm.
[0054] S3, Extrusion of the coating layer:
[0055] The coating was performed using a miniature co-rotating twin-screw extruder.
[0056] Add polyimide (PI) granules to the extruder hopper. Set the temperatures of each zone of the extruder as follows: Zone 1 300℃, Zone 2 340℃, Zone 3 360℃, and Die Head 350℃, with a temperature control accuracy of ±1.5℃.
[0057] The core material with the transition layer is used as a conductive wire and passed through the cross die of the extruder head at a speed of 10 m / min. The extruder extrudes molten polyimide at a pressure of 30 MPa to coat the core material, forming a coating layer.
[0058] S4. Online heat treatment:
[0059] The extruded wire is immediately subjected to a stepped heat treatment to complete imidization and crystallization.
[0060] First stage: Keep in the oven at 120℃ for 8 minutes to completely remove residual NMP solvent from the coating layer and transition layer.
[0061] The second stage involves maintaining the temperature in a 220°C oven for 5 minutes to allow the polyimide to complete the imidization reaction, while simultaneously promoting interfacial diffusion and fusion between the transition layer, core material, and coating layer.
[0062] The third stage involves maintaining the temperature in a 320℃ oven for 2 minutes to allow the polyimide molecular chains to fully arrange themselves, complete crystallization, and improve the mechanical properties and heat resistance of the coating layer.
[0063] S5, sizing cooling:
[0064] The heat-treated wire is fed into a precision sizing mold to precisely control its final outer diameter to 0.25 mm (i.e., the thickness of the coating layer on one side is 0.025 mm).
[0065] Subsequently, the wire is cooled and shaped using a water-cooling tank, with the water temperature controlled at 20°C.
[0066] S6. Winding Inspection:
[0067] The finished wire is wound up using an automatic winding machine.
[0068] Performance testing was conducted on the wound wire: The composite wire showed a dimensional change rate of only 0.3% within a temperature range of -50℃ to 200℃; a bending test was conducted according to the standard GB / T 4909.7-2009, and the wire withstood 6000 bending cycles (R=10d=2mm) without cracking, demonstrating excellent interfacial bonding.
[0069] Example 2 (for medical device leads):
[0070] This embodiment provides a processing technology for composite wires, the steps of which are basically the same as those in Embodiment 1, the difference being:
[0071] Core material: Annealed soft copper wire with a diameter of 0.1mm.
[0072] S1 roughening treatment: Chemical etching was used, with FeCl3 solution used for 1 minute to etch, and the surface roughness Ra was controlled at 1.5μm.
[0073] Preparation of S2 transition layer: Electrostatic spraying was used. Silver powder (50wt%) and polyurethane resin were dissolved in a mixed solvent to form a suspension. The spraying voltage was 40kV, and the thickness of the transition layer was achieved to 0.01mm by controlling the wire feed speed (3m / min) and the spraying time.
[0074] S3 coating: The material is polytetrafluoroethylene (PTFE), the extrusion temperature is set to 380℃, the extrusion pressure is 15MPa, and the extrusion speed is 8m / min.
[0075] S4 Online Heat Treatment:
[0076] First stage: 100℃, 10min;
[0077] Second stage: 180℃, 8 minutes;
[0078] Third stage: 280℃, 3min.
[0079] The final product has an outer diameter of 0.13mm. This wire is extremely flexible, has excellent chemical resistance, and is suitable for frequent bending and harsh chemical environments.
[0080] Comparative example:
[0081] Using traditional processes: the transition layer preparation step S2 is omitted, and the stepped heat treatment S4 is eliminated. The coating layer is directly extruded onto the core material and then simply cooled.
[0082] Results: The prepared wire showed a dimensional change rate of 1.2% when tested at 200℃; after only 800 bending tests, the cladding layer showed obvious cracks and separated from the core material.
[0083] In summary:
[0084] This invention significantly improves the interfacial bonding force between the metal core and the polymer coating layer through a unique "transition layer" design and "stepped online heat treatment" process, solving industry problems such as interfacial separation, poor temperature resistance, and easy bending and cracking caused by differences in the thermal expansion coefficients of materials.
[0085] The data from the examples contrast sharply with those from the comparative examples, fully demonstrating the technological advancements and beneficial effects of the present invention.
[0086] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0087] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A processing technology for composite wires, characterized in that, Includes the following steps: S1. Core material pretreatment: The metal core material is cleaned and roughened. S2. Transition layer preparation: A transition layer is formed on the surface of the core material by electrostatic spraying or solution impregnation. S3, Coating Layer Extrusion: A polymer layer is coated onto the outer surface of the transition layer using a micro extruder; S4. Online heat treatment: The coated wire is subjected to stepped heat treatment; S5. Sizing and Cooling: The outer diameter of the wire is precisely controlled by a sizing mold, and then cooled and shaped. S6. Winding Inspection: Wind the wire and perform performance testing.
2. The processing technology for a composite wire according to claim 1, characterized in that: The surface cleaning in S1 employs a combination of alkaline degreasing and acid pickling activation. The roughening treatment in S1 is performed by sandblasting or chemical etching, and the surface roughness Ra is controlled between 1.0 and 3.0 μm.
3. The processing technology for a composite wire according to claim 1, characterized in that: The electrostatic spraying voltage in S2 is 30-60kV, and the spraying thickness is controlled by the wire feeding speed and spraying time. The solution impregnation in S2 adopts a multiple impregnation-drying process, with the number of impregnations being 2-4 times.
4. The processing technology for a composite wire according to claim 1, characterized in that: The extrusion temperature of the micro extruder in S3 is determined according to the polymer material, and the temperature control accuracy is ±2℃. The extrusion pressure in S3 is 10-50 MPa, and the extrusion speed is 5-20 m / min.
5. The processing technology for a composite wire according to claim 1, characterized in that: The stepped heating process in S4 includes three stages: First stage: 80-120℃, keep warm for 5-10 minutes to remove residual solvent; Second stage: 150-250℃, keep warm for 3-8 minutes to promote interface fusion; Third stage: 280-350℃, hold for 1-3 minutes to complete crystallization.
6. A composite wire, prepared using the composite wire processing technology as described in any one of claims 1-5, characterized in that: It includes a core material (1) and a covering layer (2) covering the outer surface of the core material (1); The core material (1) is a metallic material, and the covering layer (2) is a polymer material; A transition layer (3) is provided between the core material (1) and the covering layer (2), and the transition layer (3) is a composite material of metal and polymer.
7. A composite wire according to claim 6, characterized in that: The core material (1) is copper or copper alloy with a conductivity ≥58MS / m; the diameter of the core material (1) is 0.05-2.0mm.
8. A composite wire according to claim 6, characterized in that: The coating layer (2) is one of polytetrafluoroethylene, polyimide or polyetheretherketone; the thickness of the coating layer (2) is 0.01-0.2 mm.
9. A composite wire according to claim 6, characterized in that: The transition layer (3) is a polymer composite material containing metal powder, with a metal powder content of 30-60 wt%; the thickness of the transition layer (3) is 0.005-0.05 mm.
10. A composite wire according to claim 6, characterized in that: The dimensional change rate of the composite wire is ≤0.5% within a temperature range of -50℃ to 200℃; the composite wire has a bending resistance of ≥5000 cycles.