Multifunctional composite layer structure cable material and preparation method thereof

Abstract

The invention provides a preparation method of a multifunctional composite layer structure cable material. The preparation method comprises the following steps: performing surface activation pretreatment on conductive fibers; mixing the pretreated conductive fibers with an insulating polymer in proportion, and uniformly distributing the mixture on a substrate through a spin coating technology to form a conductive layer; laying a layer of composite material formed by mixing a nano filler and a flame retardant on the surface of the conductive layer, and compacting through a lamination technology to form a protective composite layer; mixing a functional reinforcing material with high-performance resin, and uniformly covering the protective composite layer with the mixture in a spraying manner to form a heat-conducting, electric-conducting and structure-reinforced functional reinforcing layer; and applying a layer of weather-resistant high polymer material on the surface of the function enhancement layer, and covering through an impregnation process to form a durable external protection layer to obtain the cable material. The comprehensive improvement of the cable material in the aspects of signal transmission, mechanical strength, heat and electricity conduction, environmental adaptability and the like is realized.

Description

Technical Field

[0001] The invention relates to the field of electric wires and cables, and in particular to a multifunctional composite layer structure cable material and a preparation method thereof. Background Art

[0002] In the current era of rapid development of industrial automation and intelligent manufacturing, high-precision robotic equipment, flexible and reconfigurable production lines, and high-reliability sensor systems are becoming increasingly popular. These new-generation industrial applications not only require stable signal and energy transmission, but also place higher demands on transmission cables in terms of conductivity, mechanical strength, environmental tolerance, flame retardancy, and thermal management capabilities. In order to ensure the continuous operation of production lines in high and low temperature differences, strong mechanical vibrations, dust, oil pollution, and corrosive chemical environments, high-performance cable materials and preparation technologies suitable for smart factories and automated production equipment have become the focus of research and development in related fields.

[0003] In the prior art, traditional cables often use a single layer or a simple composite structure to meet basic transmission and protection needs. For example, commonly used industrial cables are mostly made by coating a layer of ordinary polymer insulation on the outside of the conductor, plus a basic protective layer to achieve basic mechanical protection and simple environmental adaptability. However, this traditional solution has obvious shortcomings: the lack of functional coatings and refined multi-level structural design causes the reliability of the cable to drop sharply in high temperature, continuous vibration, oil pollution and chemical corrosion environments; the bonding force between the conductive layer and the substrate is insufficient, and the conductive efficiency and transmission stability are significantly attenuated after long-term use, and there may even be problems such as insulation layer shedding, outer layer cracking or internal structure degradation. It is precisely to address the technical defects of the above-mentioned traditional industrial cables that perform poorly under harsh operating environments and high-standard functional requirements that the present invention proposes a method for preparing a multifunctional composite layer structure cable material to effectively improve the long-term stability and comprehensive performance of cables in industrial automation and intelligent manufacturing application scenarios. Summary of the invention

[0004] To achieve the above object, the present invention provides a method for preparing a multifunctional composite layer structure cable material, comprising the steps of:

[0005] S1. Surface activation pretreatment of the conductive fiber;

[0006] S2, mixing the pretreated conductive fibers and insulating polymer in proportion, uniformly distributing them on the substrate by spin coating technology to form a conductive layer, and curing them at 150-200° C. by hot pressing process;

[0007] S3, laying a layer of composite material mixed with nano filler and flame retardant on the surface of the conductive layer, compacting it by lamination technology to form a protective composite layer, and controlling the lamination pressure at 30-50 kg / cm 2between;

[0008] S4, mixing the functional reinforcement material with the high-performance resin, uniformly covering the protective composite layer by spraying to form a functional reinforcement layer, and using ultraviolet curing technology to complete the rapid curing of the functional reinforcement layer within 80 to 120 seconds;

[0009] S5. Apply a layer of weather-resistant polymer material on the surface of the functional enhancement layer, cover it through an impregnation process to form a durable external protective layer, heat-treat the external protective layer at a temperature controlled between 180 and 220° C., and obtain the multifunctional composite layer structure cable material.

[0010] In some embodiments of the present invention, the conductive fiber is selected from one or more of carbon fiber, silver-coated fiber, stainless steel fiber or copper-based fiber; the insulating polymer is selected from one or more of polyethylene, polypropylene, polyvinyl chloride, polytetrafluoroethylene or polyimide; the nanofiller is selected from one or more of nano-alumina, nano-silicon, nano-titanium dioxide, nano-carbon tube or nano-graphene; the flame retardant is selected from one or more of brominated flame retardants, phosphorus flame retardants, aluminum hydroxide, magnesium hydroxide or organic phosphorus flame retardants; the reinforcing filler is selected from one or more of glass fiber, aramid fiber, carbon fiber, silicate fiber, nano-carbon tube, graphene sheet or polyester fiber; the high-performance resin is selected from one or more of epoxy resin, polyamide resin, polyurethane resin, unsaturated polyester resin or phenolic resin; the weather-resistant polymer material is selected from one or more of polyvinyl chloride, polyester elastomer, polyacrylonitrile, polybutadiene or fluorocarbon polymer material.

[0011] In some embodiments of the present invention, in the conductive layer, calculated by weight percentage, the conductive fibers account for 10-30 wt % and the insulating polymer accounts for 70-90 wt %.

[0012] In some embodiments of the present invention, the substrate is formed by laminating one or more of a metal foil, a high-performance polymer film, a glass fiber substrate and a ceramic substrate.

[0013] In some embodiments of the present invention, the metal foil includes one or more of copper foil, stainless steel foil or aluminum foil; the high-performance polymer film includes one or more of polyester film, polyimide film or polytetrafluoroethylene film; the glass fiber substrate is glass fiber reinforced plastic; the ceramic substrate includes one or more of alumina ceramic or silicon nitride ceramic.

[0014] In some embodiments of the present invention, the preprocessing in step S1 includes:

[0015] S1.1, soaking the conductive fiber in deionized water for 30 to 60 minutes at a temperature of 20 to 30°C; using an ultrasonic cleaning device to assist in cleaning the conductive fiber at an ultrasonic frequency of 30 to 50 kHz for 10 minutes;

[0016] S1.2, soaking the conductive fiber in a 20-30% nitric acid solution or a 10-20% sulfuric acid solution by slow stirring for 15-30 minutes at a temperature of 50-70°C;

[0017] S1.3, take out the conductive fiber, rinse it repeatedly with deionized water until it is neutral, and soak the neutralized conductive fiber in a solution containing 10% silane coupling agent for 50 to 60 minutes at a temperature of 30 to 50°C;

[0018] S1.4, spraying a layer of nano-silicon dioxide coating on the surface of the conductive fiber, using a spraying device, the spraying temperature is 70-90°C, the coating thickness is controlled at 50nm, and low-temperature plasma treatment is used, specifically using oxygen or argon plasma, the power is 100W, the treatment time is 5min, and a microscopic rough structure is formed on the surface of the nano-silicon dioxide coating;

[0019] S1.5 Spread the treated conductive fibers evenly on a drying plate, place in a drying oven, dry at 60-80° C. for 2-4 hours, and cool to room temperature after drying.

[0020] In some embodiments of the present invention, the method for preparing the multifunctional composite layer structure cable material according to claim 1 is characterized in that step S2 comprises:

[0021] S2.1, the pretreated conductive fiber and the insulating polymer are mixed in proportion, N, N-dimethylformamide or dimethyl sulfoxide solvent is added for dilution, the mass ratio of the solvent to the total solid is (60-70): (30-40), a high-speed disperser is used to stir at a speed of 5000r / min for 20-40min, and an ultrasonic dispersion device is set to a frequency of 30-50kHz and a power of 200W to treat the mixture for 15min to form a mixed slurry;

[0022] S2.2, placing the substrate in a cleaning tank, cleaning the surface with isopropyl alcohol, and after cleaning, placing the substrate in a plasma cleaning machine, using oxygen plasma for 5 min at a power of 100 W to enhance the hydrophilicity and adhesion of the substrate surface;

[0023] S2.3, fix the pretreated substrate on the vacuum chuck of the spin coater, ensure that its surface is flat and free of bubbles, use a dropper to evenly drip the mixed slurry on the center of the substrate, the dripping amount is 0.5 ml per square centimeter, start the spin coater, rotate at a speed of 500 r / min for 10 seconds in the first stage to evenly spread the slurry; rotate at a speed of 2000 r / min for 30 seconds in the second stage to form a uniform coating, and remove excess slurry;

[0024] S2.4, during the spin coating process, an electrostatic field-assisted technology is introduced, by providing a high voltage electrode below the substrate and a grounded metal mesh above the substrate to form an electrostatic field, and by adjusting the intensity and direction of the electrostatic field, the microstructure of the coating is optimized;

[0025] S2.5. Transfer the coated substrate to a hot press, control the pressure to 5 MPa, and control the temperature through a program. Preheat at 100° C. for 10 min, then heat to 150-200° C. for curing, and the duration is 30 min.

[0026] In some embodiments of the present invention, in step S2.4, the electrostatic field assisted technology is specifically: by fine-tuning the distance between the high-voltage electrode and the substrate in the range of 5 to 20 mm, and regulating the voltage between 3 and 7 kV, the magnitude of the electrostatic field strength can be changed; at the same time, a plurality of lateral electrodes that can independently apply potentials are arranged around the substrate, so that the electric field is inclined in a specific direction or distributed in a surrounding manner; a mechanical fine-tuning mechanism that can be precisely positioned is provided on the electrode mounting bracket, and the direction of the electric field is further refined and controlled by adjusting the rotation angle.

[0027] In some embodiments of the present invention, in step S3, the lamination technology is 30-50 kg / cm 2 The pressure is 100-200°C and the temperature is between 150°C and 180°C. Double-sided heated pressing rollers are used for continuous pressing for 30 seconds. Ultrasonic vibration is introduced during the pressing process with a frequency of 30-50kHz to promote a more uniform dispersion of the nanofiller.

[0028] In step S4, the spraying method is to spray the mixed solution at a constant air pressure of 0.2 MPa through a high-precision atomizing nozzle at 40-60° C., and apply a weak electric field of 1 kV in the direction of the substrate plane to align the droplets and optimize the distribution of the function enhancement layer;

[0029] In step S5, the immersion process is to slowly immerse the substrate into a solution containing weather-resistant polymer materials and micron-sized hollow spherical particles at an immersion speed of 1 mm / s, and promote the uniform distribution of the particles inside the coating through ultrasonic oscillation of 30 to 40 kHz to form an external protective layer with a microporous structure and excellent weather resistance; wherein the micron-sized hollow spherical particles include one or more of hollow alumina, hollow silica, hollow polystyrene, hollow polyacrylate and hollow polyimide microspheres.

[0030] The present invention proposes a multifunctional composite layer structure cable material, which is prepared by the preparation method of the multifunctional composite layer structure cable material as described above. The multifunctional composite layer structure cable material includes a substrate, a conductive layer, a protective composite layer, a function enhancement layer and an external protective layer which are stacked in sequence.

[0031] Compared with the prior art, the multifunctional composite layer structure cable material and the preparation method thereof in the present invention have the following beneficial effects:

[0032] This preparation method significantly improves the comprehensive performance of cable materials through the fine design of multi-layer composite structures and the application of advanced processes. First, the surface activation treatment enhances the bonding force between the conductive fiber and the insulating polymer, and improves the conductivity and mechanical strength of the cable material. Secondly, the introduction of nanofillers and flame retardants not only improves the flame retardant properties of the cable material, but also enhances its protection ability, ensuring safety and reliability in harsh environments. The thermal conductivity and structural strengthening effects of the functional reinforcement layer further optimize the thermal management and mechanical properties and extend the service life. At the same time, the application of weather-resistant polymer materials gives the cable material excellent environmental adaptability, allowing it to maintain stable performance under complex working conditions such as high temperature, low temperature, humidity and corrosion. Overall, the multifunctional composite layer structure cable material prepared by this method has excellent electrical properties, mechanical strength and environmental tolerance, meets the strict requirements for efficient energy transmission, lightweight and high durability, and has broad application prospects and significant market competitiveness. DETAILED DESCRIPTION

[0033] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0034] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0035] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0036] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.

[0037] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0038] The present invention provides a method for preparing a multifunctional composite layer structure cable, comprising the steps of:

[0039] S1. Surface activation pretreatment of the conductive fiber;

[0040] Step S1 performs surface activation pretreatment on the conductive fiber to enhance its bonding force with the insulating polymer.

[0041] Wherein, the conductive fiber is selected from one or more of carbon fiber, silver-coated fiber, stainless steel fiber or copper-based fiber.

[0042] In one embodiment of the present invention, step S1 includes:

[0043] S1.1. Soak the conductive fiber in deionized water for 30 to 60 minutes, for example, 30 minutes, 45 minutes, or 60 minutes, and control the temperature at 20 to 30°C, for example, 25°C or 30°C; use ultrasonic cleaning equipment to assist in cleaning the conductive fiber, with an ultrasonic frequency of 30 to 50 kHz, for example, 40 kHz, and a duration of 10 minutes.

[0044] Dust, oil and other impurities on the surface of the conductive fiber can be removed by cleaning, and ultrasonic cleaning can further improve the cleaning effect.

[0045] S1.2, soak the conductive fiber in a nitric acid or sulfuric acid solution of appropriate concentration by slowly stirring, the soaking time is 15 to 30 minutes, for example, 15 minutes, 22 minutes, 30 minutes; wherein, the specific time is 20 minutes, and the temperature is controlled at 50 to 70° C., for example, 60° C. The mass fraction of the sulfuric acid solution used is 10% to 20%, and the mass fraction of the nitric acid solution is 20% to 30%, for example, 10% sulfuric acid and 25% nitric acid.

[0046] This step is to increase the roughness of the fiber surface and introduce hydroxyl groups. Slow stirring is used to ensure that the solution evenly contacts the conductive fibers to avoid local excessive corrosion.

[0047] By fixing the specific concentration values ​​of nitric acid and sulfuric acid, the repeatability of the acid etching step and the consistency of the treatment effect are ensured, thereby improving the stability of the cable preparation process. Multiple acid agent options: The concentration range and fixed values ​​of both nitric acid and sulfuric acid are provided at the same time, which enhances the applicability and flexibility of the method and adapts to the surface activation requirements of different conductive fiber materials. Optimizing the surface activation effect: Reasonable acid concentration range and fixed value selection help to improve the surface activity and bonding properties of the conductive fiber while avoiding adverse effects on the fiber structure, thereby ensuring the performance and reliability of the final cable.

[0048] S1.3. Take out the conductive fiber, rinse it repeatedly with deionized water until it is neutral, and soak the neutralized conductive fiber in a solution containing 10% silane coupling agent (such as APTES, 3-aminopropyltriethoxysilane) for 50 to 60 minutes. The temperature is controlled at 30 to 50°C, for example, it can be soaked for 60 minutes at 40°C.

[0049] Soaking in silane coupling agent solution can introduce amino functional groups and enhance the bonding force between the fiber and the polymer matrix.

[0050] S1.4. Spray a layer of nano-silicon dioxide coating on the surface of the conductive fiber using spraying equipment, the spraying temperature is 70-90°C, the coating thickness is controlled at 50nm, and low-temperature plasma treatment is used, specifically using oxygen or argon plasma, the power is 100W, the treatment time is 5min, and a microscopic rough structure is formed on the surface of the nano-silicon dioxide coating.

[0051] The microscopic rough structure formed by nano-silica coating and low-temperature plasma treatment provides the conductive fiber with a larger surface area and more surface protrusions and depressions. Such a microscopic uneven surface can form more mechanical intercalation when in contact with the polymer matrix, making it easier for the polymer molecular chains to infiltrate and fill these tiny gaps, thereby forming a stable solid-solid interface coupling on the fiber surface. In addition, the microscopic rough structure can also increase the number of effective contact points on the fiber surface, providing more binding sites for various chemical bonds and weak van der Waals forces, thereby enhancing the bonding performance and interface strength between the conductive fiber and the polymer as a whole, so that the final composite material can still maintain excellent structural stability and conductive properties under mechanical loads and environmental stresses.

[0052] S1.5. Spread the treated conductive fibers evenly on a drying plate, place in a drying oven, and dry at 60-80°C for 2-4 hours. For example, the temperature may be 60°C, 70°C, or 80°C, and the drying time may be 2 hours, 3 hours, or 4 hours. After drying, cool to room temperature.

[0053] The drying step is to remove surface moisture and solvents to ensure that the fibers are dry and ready for the next step of composite preparation.

[0054] Through detailed surface activation pretreatment steps, this method effectively enhances the bonding force between the conductive fiber and the insulating polymer, significantly improving the conductivity and mechanical strength of the cable. The introduction of ultrasonic-assisted cleaning and nano-silica coating ensures thorough cleaning and high activity of the fiber surface, optimizing the interfacial bonding between the fiber and the polymer matrix. Low-temperature plasma treatment further improves the microstructure of the fiber surface, improving the bonding performance and the overall stability of the composite material. Ultimately, the pretreated conductive fiber has more excellent surface properties, making the prepared multifunctional composite layer structure cable show more superior performance in terms of conductivity, mechanical strength and environmental adaptability.

[0055] S2. Mix the pretreated conductive fibers and insulating polymers in proportion, evenly distribute them on the substrate by spin coating technology to form a conductive layer, and use a hot pressing process to cure them at 150-200°C, for example, 150°C, 175°C, or 200°C; wherein the insulating polymer is selected from one or more of polyethylene, polypropylene, polyvinyl chloride, polytetrafluoroethylene, or polyimide.

[0056] Calculated by weight percentage, the conductive fiber accounts for 10-30wt% and the insulating polymer accounts for 70-90wt%. For example, the conductive fiber: insulating polymer ratio can be 10:90, 20:80, or 30:70.

[0057] The substrate is formed by laminating one or more of metal foil, high-performance polymer film, glass fiber substrate and ceramic substrate.

[0058] Metal foil has excellent conductivity and mechanical strength, and is suitable for cables that require high conductivity and structural stability; high-performance polymer film has good insulation and flexibility, and is suitable for cables that require lightweight and high insulation performance; glass fiber substrate provides good mechanical strength and heat resistance, and is suitable for cables used in high-strength and high-temperature environments; ceramic substrate has excellent heat resistance and corrosion resistance, and is suitable for cables in extreme environmental conditions; the use of composite substrate combines the advantages of multiple materials and can customize the performance of cables according to specific needs.

[0059] The metal foil includes one or more of copper foil, stainless steel foil or aluminum foil; the high-performance polymer film includes one or more of polyester film, polyimide film or polytetrafluoroethylene film; the glass fiber substrate is glass fiber reinforced plastic; and the ceramic substrate includes one or more of alumina ceramic or silicon nitride ceramic.

[0060] Step S2 includes:

[0061] S2.1. Mix the pretreated conductive fiber and the insulating polymer in proportion, add N,N-dimethylformamide or dimethyl sulfoxide solvent for dilution, the mass ratio of the solvent to the total solid is (60-70): (30-40), for example, it can be 60:40, 70:30, use a high-speed disperser to stir at a speed of 5000r / min for 20-40min, for example, it can be 20min, 30min, 40min, set the frequency of ultrasonic dispersion equipment to 30-50kHz, the power is 200W, and the mixture is treated for 15min to form a mixed slurry;

[0062] S2.2, placing the substrate in a cleaning tank, cleaning the surface with isopropyl alcohol, and after cleaning, placing the substrate in a plasma cleaning machine, using oxygen plasma for 5 minutes at a power of 100 W to enhance the hydrophilicity and adhesion of the substrate surface;

[0063] S2.3, fix the pretreated substrate on the vacuum chuck of the spin coater, ensure that its surface is flat and free of bubbles, use a dropper to evenly drop the mixed slurry on the center of the substrate, the drop amount is 0.5 ml per square centimeter, start the spin coater, rotate at 500r / min for 10 seconds in the first stage to spread the slurry evenly; rotate at 2000r / min for 30 seconds in the second stage to form a uniform coating, and remove excess slurry;

[0064] S2.4. During the spin coating process, an electrostatic field-assisted technology is introduced to form an electrostatic field by setting a high-voltage electrode under the substrate and a grounded metal mesh above the substrate.

[0065] The action of the electrostatic field can guide the charged conductive fibers and insulating polymer particles to be more evenly distributed in the coating and control the deposition direction and arrangement of the particles, thereby achieving precise control over the microscopic particle size and distribution.

[0066] By adjusting the intensity and direction of the electrostatic field, the microstructure of the coating is optimized and the interfacial bonding between the conductive fibers and the insulating polymer and the substrate is improved.

[0067] In step S2.4, the electrostatic field-assisted technology is specifically as follows: by fine-tuning the distance between the high-voltage electrode and the substrate in the range of 5 to 20 mm and regulating the voltage between 3 and 7 kV, the electrostatic field strength is changed to control the microscopic distribution density of the conductive fibers and the insulating polymer particles; at the same time, a plurality of lateral electrodes that can independently apply potentials are arranged around the substrate to make the electric field tilted in a specific direction or distributed in a circumferential direction, thereby achieving flexible changes in the direction of the electric field and gradient adjustment; in addition, a mechanical fine-tuning mechanism that can be precisely positioned can be set on the electrode mounting bracket to further refine the control of the electric field direction by adjusting the rotation angle.

[0068] The electrostatic field strength is proportional to the voltage applied between the electrodes. When the electrostatic field strength needs to be increased to make the particles more densely distributed or reduce particle agglomeration, the voltage can be gradually increased from the original 5kV to 6kV, 7kV or even higher; if the electrostatic field strength needs to be weakened to prevent excessive directional arrangement, the voltage can be reduced to 4kV or 3kV. By raising and lowering the voltage, the electric field strength can be flexibly adjusted within a range.

[0069] Shortening the distance between electrodes can increase the electric field strength, while increasing the distance between electrodes can reduce the electric field strength. The experimental device can be designed with movable electrodes or equipped with a precise mechanical fine-tuning platform to achieve fine control of the electric field strength by changing the distance between the electrode and the substrate (for example, from 10 mm to 5 mm or 20 mm).

[0070] When there is a high voltage electrode under the substrate and a grounded metal mesh above it, the direction of the electric field is mainly vertical. If lateral electrodes are added (for example, a set of energized auxiliary electrodes are set on both sides of the substrate), the horizontal component can be introduced on the basis of the vertical field by adjusting the voltage of the lateral electrodes, thereby fine-tuning the direction of the electric field in two-dimensional space. By controlling the potential of each lateral electrode separately, the electric field can have a certain tilt or horizontal offset, thereby guiding the distribution and orientation of particles in a specific direction.

[0071] Arrange multiple electrode arrays with independently adjustable voltages around the substrate (e.g., one electrode in each of the four directions), and selectively apply high or low voltages to some of the electrodes as needed to form a composite electric field. By precisely controlling the potential distribution of each electrode, more flexible electric field direction control can be achieved within the plane, such as tilting the electric field to a specific side, or gradually changing the electrode excitation sequence during the coating process, so that the particle distribution presents a controllable gradient or orderly distribution over time.

[0072] In addition to electrical regulation, mechanical structure can also be used. For example, the substrate fixture can be installed on a rotatable bracket, and the orientation of the substrate surface relative to the electrode can be changed by adjusting the bracket's rotation angle, thereby changing the relative relationship between the electric field action direction and the substrate plane. Combined with voltage regulation and multi-electrode array design, dynamic changes in the electric field direction can be achieved during the coating process.

[0073] To ensure that the electric field strength and direction are adjusted accurately and effectively, an electric field sensor can be integrated into the device or an optical microscope can be used to observe the distribution of coating particles in real time. When the electric field sensor or online image analysis finds that the particle distribution is uneven or not as expected, the voltage, electrode spacing or excitation voltage of the lateral electrode can be fine-tuned immediately to achieve closed-loop feedback control and ensure that the particles are distributed in an ideal direction. For example, when the particles are significantly dense in a certain area, resulting in uneven distribution, the main electrode voltage is appropriately increased (such as from 5kV to 5.5kV) to enhance the driving force of the particles to migrate outward from the aggregation point under the electric field force; at the same time, the excitation voltage of the lateral electrode is slightly increased (increased by about 5-10%), and the particles are guided to diffuse to a wider range by increasing the lateral electric field component; when the particles are dense in the edge area of ​​the substrate and sparse in the central area, the lateral electrode voltage is reduced (reduced by about 10%) to weaken the lateral pulling force of the electric field at the edge, so that the particles no longer excessively gather to the edge; at the same time, the electrode spacing is slightly increased (such as from 10mm to 12mm), the overall electric field strength is slightly weakened, and the particles are helped to stay in the central area and fill the sparse area; when the particles are arranged in no obvious direction and are randomly distributed, the lateral electrode excitation voltage is fine-tuned (increased or decreased by about 5%) to change the distribution of the electric field direction, so that the force on the particles has a clearer directionality; If the directional effect is still not ideal, the main electrode voltage can be gradually increased or decreased (0.5 kV each time as the adjustment range) after feedback monitoring to find the optimal electric field strength to achieve better directional arrangement; when there are void areas with a serious shortage of particles on the substrate surface, the electrode spacing can be appropriately reduced (such as from 12 mm to 9 mm) to increase the local electric field strength and guide distant particles to migrate to the void area; at the same time, the lateral electrode voltage can be fine-tuned (up and down by 5%) to slightly deflect the direction of the electric field, "push" the particles into the blank area, and gradually fill the scarce areas; when the particles aggregate in clusters, resulting in uneven particle size distribution, the main electrode voltage can be reduced (such as from 6 kV to 4.5 kV) to weaken the degree of particle acceleration, thereby reducing agglomeration; at the same time, the lateral electrode voltage can be slightly increased (by about 5%) to disperse the particles in the horizontal direction, and the local electric field gradient can be increased by slightly adjusting the electrode spacing (for example, shortening it by 2 mm) to assist in particle deagglomeration and redistribution.

[0074] S2.5. Transfer the coated substrate to a hot press, control the pressure to 5 MPa, and preheat at 100°C for 10 min through program temperature control, then heat to 150-200°C for curing, for example, 150°C, 165°C, 200°C, and the duration is 30 min.

[0075] Ensure that the solvent inside the coating is fully volatilized and achieve close bonding between the conductive fibers and the insulating polymer.

[0076] The conductive layer prepared by this method has excellent uniformity and microstructure by using the spin coating step and innovative electrostatic field assisted technology. High-speed dispersion and ultrasonic treatment ensure the full mixing and dispersion of the conductive fiber and the insulating polymer, while the electrostatic field assisted technology further optimizes the distribution and arrangement of the particles, significantly improving the interfacial bonding force between the conductive fiber and the insulating polymer. The conductive layer finally prepared has better conductivity and mechanical strength, laying a solid foundation for improving the overall performance of the multifunctional composite layer structure cable.

[0077] S3. Lay a layer of composite material mixed with nano fillers and flame retardants on the surface of the conductive layer, compact it through lamination technology to form a protective composite layer, and control the lamination pressure at 30-50kg / cm 2 , for example, it can be 30kg / cm 2 , 40kg / cm 2 , 50kg / cm 2 , wherein the nanofiller is selected from one or more of nano-alumina, nano-silicon, nano-titanium dioxide, nano-carbon tubes or nano-graphene; and the flame retardant is selected from one or more of brominated flame retardants, phosphorus flame retardants, aluminum hydroxide, magnesium hydroxide or organic phosphorus flame retardants.

[0078] In step S3, the lamination technology is to continuously press for 30 seconds using a double-sided heated press roller at a temperature of 150 to 180°C, for example, 150°C, 170°C, 180°C, and introduce ultrasonic vibration with a frequency of 30 to 50 kHz during the pressing process to promote a more uniform dispersion of the nanofiller;

[0079] Through lamination, the composite layers are precisely aligned to ensure the bonding between the layers. Vibration is introduced during the lamination process to reduce the generation of bubbles and improve the uniformity and surface quality of the composite layers.

[0080] S4. Mix the functional reinforcing material with the high-performance resin, and evenly cover the protective composite layer by spraying to form a functional reinforcing layer that is thermally conductive, electrically conductive and structurally reinforced, and use ultraviolet curing technology to complete the rapid curing of the functional reinforcing layer within 80 to 120 seconds, for example, 80 seconds, 95 seconds, or 120 seconds; wherein the reinforcing filler is selected from one or more of glass fiber, aramid fiber, carbon fiber, silicate fiber, carbon nanotube, graphene sheet or polyester fiber, and the high-performance resin is selected from one or more of epoxy resin, polyamide resin, polyurethane resin, unsaturated polyester resin or phenolic resin.

[0081] In step S4, the spraying method is to spray the mixed solution at 40-60°C through a high-precision atomizing nozzle at a constant air pressure of 0.2 MPa, for example, 40°C, 50°C, and apply a weak electric field of 1 kV in the direction of the substrate plane to orient the droplets, thereby optimizing the microscopic particle size distribution of the function enhancement layer.

[0082] Make the coating evenly covered, and combine the repeated spraying process to achieve more uniform and precise functional coating thickness control, and adjust the spraying thickness according to the measurement results after each coating to ensure that the final coating is uniform and defect-free.

[0083] S5. Apply a layer of weather-resistant polymer material on the surface of the function enhancement layer and cover it through an impregnation process to form a durable external protective layer; perform heat treatment and control the temperature between 180 and 220° C., wherein the weather-resistant polymer material is selected from one or more of polyvinyl chloride, polyester elastomer, polyacrylonitrile, polybutadiene or fluorocarbon polymer materials.

[0084] In step S5, the immersion process is to slowly immerse the substrate into a solution containing weather-resistant polymer materials and micron-sized hollow spherical particles at an immersion speed of 1 mm / s, and promote the uniform distribution of the particles inside the coating through ultrasonic oscillation of 30 to 50 kHz, thereby forming an external protective layer with a microporous structure and excellent weather resistance; wherein the micron-sized hollow spherical particles include one or more of hollow alumina, hollow silica, hollow polystyrene, hollow polyacrylate and hollow polyimide microspheres.

[0085] The coating is carried out by vacuum impregnation technology, in which the substrate is immersed in a liquid solution containing resin, and the immersion time is maintained for 30 minutes under vacuum conditions. The temperature is controlled at 25-30°C. By removing the bubbles in the solution, it is ensured that each inner layer is fully infiltrated and coated, avoiding the formation of bubbles while optimizing the chemical bonding of the material.

[0086] This preparation method gradually constructs a cable material with excellent performance through a multi-layer composite structure design. First, step S1 performs surface activation pretreatment on the conductive fiber to enhance its bonding with the insulating polymer. Then, step S2 mixes the pretreated conductive fiber with the insulating polymer in proportion, evenly distributes it on the substrate through a spin coating technique to form an efficient conductive layer, and cures it through a hot pressing process to ensure the stability and consistency of the conductive layer. Step S3 lays a composite material mixed with nanofillers and flame retardants on the surface of the conductive layer, compacts it using lamination technology, forms a protective composite layer, and provides mechanical protection and flame retardant properties. Subsequently, step S4 mixes the functional reinforcing material with a high-performance resin, evenly covers it on the protective composite layer by spraying, forms a reinforcing layer with thermal conductivity, electrical conductivity and structural strengthening functions, and uses ultraviolet curing technology to quickly cure it to improve the interlayer bonding and overall structural strength. Finally, step S5 applies a weather-resistant polymer material on the surface of the functional enhancement layer, covers it through an impregnation process to form a durable external protective layer, and performs heat treatment to ensure that the layers are firmly bonded, ultimately obtaining a multifunctional composite layer structure cable material with high conductivity, excellent mechanical strength and outstanding environmental adaptability.

[0087] The present invention also proposes a multifunctional composite layer structure cable material, including a substrate, a conductive layer, a protective composite layer, a functional enhancement layer and an external protective layer which are stacked in sequence. The conductive fiber is pre-treated with surface activation in sequence, mixed with an insulating polymer and then spin-coated and hot-pressed to form a uniform and dense conductive layer; a composite material mixed with nanofillers and flame retardants is laid on it, and a protective layer with mechanical reinforcement and safe flame retardant properties is formed by compaction using a lamination process; a high-performance resin is then mixed with a functional enhancement material, and a functional enhancement layer with heat conduction, electricity conduction and structural reinforcement is quickly constructed by spraying and ultraviolet curing; finally, a weather-resistant polymer material is impregnated or coated on its surface and heat-treated to obtain an external protective layer with excellent environmental adaptability and long-term stability, thereby preparing a multifunctional composite layer structure cable material with multi-level functions and reliable and durable properties.

[0088] The cable material of the present invention is combined with the conductor core to form a cable. First, a high-purity, low-resistivity metal wire (such as copper or silver-plated copper wire) is selected as the conductor core, and its surface is cleaned and dried to ensure good adhesion of subsequent layers; secondly, the conductive layer material formed by the aforementioned surface activation pretreatment, mixing with the insulating polymer, and then spin coating and curing is uniformly wound on the surface of the conductive core in the form of a strip or a windable semi-cured film. During the winding process, appropriate tension and stacking density must be maintained to ensure that the conductive fibers are in close contact with the insulating matrix and avoid air gaps and uneven areas; then, a protective composite layer containing nanofillers and flame retardants (this layer can be made into a strip or a tubular preformed material) previously cured and formed by lamination technology is coated on the outside of the conductive layer, and the protective layer is tightly combined with the conductive layer by hot pressing or laminating equipment to form a stable intermediate substrate with excellent protective ability outside the conductive layer; and then the wire core wound and equipped with the protective layer is subjected to During the spraying operation, a high-performance resin slurry containing functional reinforcing materials is evenly sprayed on the surface, and then quickly cured and shaped by ultraviolet curing to form a composite coating with excellent thermal conductivity, electrical conductivity and structural strengthening functions; a solution or coating containing micron-sized hollow sphere particles and weather-resistant polymer materials is evenly impregnated on the surface of the functional enhancement layer under vacuum pressure conditions to eliminate bubbles and ensure that the hollow spheres are evenly distributed in the outer coating; then, through a heat treatment process, the outer layer is cured and firmly adhered to the previous layer, thereby giving the cable excellent weather resistance, UV resistance and chemical corrosion resistance; finally, the multi-layered cable is placed in a constant temperature oven or heat treatment furnace for curing. This process helps to further improve the interlayer interface bonding force and optimize the overall mechanical, electrical and environmental adaptability characteristics of the cable. After the curing is completed, the cable is inspected and cut and sorted as necessary to meet the design specifications and performance indicators before it can be used.

[0089] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing a multifunctional composite layer structure cable material, characterized in that: Includes steps: S1. Surface activation pretreatment of the conductive fiber; S2, mixing the pretreated conductive fibers and insulating polymer in proportion, uniformly distributing them on the substrate by spin coating technology to form a conductive layer, and curing them at 150-200° C. by hot pressing process; S3, laying a layer of composite material mixed with nano filler and flame retardant on the surface of the conductive layer, compacting it by lamination technology to form a protective composite layer, and controlling the lamination pressure at 30-50 kg / cm 2 between; S4, mixing the functional reinforcement material with the high-performance resin, uniformly covering the protective composite layer by spraying to form a functional reinforcement layer, and using ultraviolet curing technology to complete the rapid curing of the functional reinforcement layer within 80 to 120 seconds; S5. Apply a layer of weather-resistant polymer material on the surface of the functional enhancement layer, cover it through an impregnation process to form a durable external protective layer, heat-treat the external protective layer at a temperature controlled between 180 and 220° C., and obtain the multifunctional composite layer structure cable material.

2. The method for preparing a multifunctional composite layer structure cable material according to claim 1, characterized in that: The conductive fiber is selected from one or more of carbon fiber, silver-coated fiber, stainless steel fiber or copper-based fiber; the insulating polymer is selected from one or more of polyethylene, polypropylene, polyvinyl chloride, polytetrafluoroethylene or polyimide; the nanofiller is selected from one or more of nano-alumina, nano-silicon, nano-titanium dioxide, nano-carbon tube or nano-graphene; the flame retardant is selected from one or more of brominated flame retardants, phosphorus flame retardants, aluminum hydroxide, magnesium hydroxide or organic phosphorus flame retardants; the reinforcing filler is selected from one or more of glass fiber, aramid fiber, carbon fiber, silicate fiber, nano-carbon tube, graphene sheet or polyester fiber; the high-performance resin is selected from one or more of epoxy resin, polyamide resin, polyurethane resin, unsaturated polyester resin or phenolic resin; the weather-resistant polymer material is selected from one or more of polyvinyl chloride, polyester elastomer, polyacrylonitrile, polybutadiene or fluorocarbon polymer material.

3. The method for preparing a multifunctional composite layer structure cable material according to claim 1, characterized in that: In the conductive layer, calculated by weight percentage, the conductive fibers account for 10-30 wt % and the insulating polymer accounts for 70-90 wt %.

4. The method for preparing a multifunctional composite layer structure cable material according to claim 1, characterized in that: The substrate is formed by compounding one or more of a metal foil, a high-performance polymer film, a glass fiber substrate and a ceramic substrate through a lamination process.

5. The method for preparing a multifunctional composite layer structure cable material according to claim 4, characterized in that: The metal foil includes one or more of copper foil, stainless steel foil or aluminum foil; the high-performance polymer film includes one or more of polyester film, polyimide film or polytetrafluoroethylene film; the glass fiber substrate is glass fiber reinforced plastic; the ceramic substrate includes one or more of alumina ceramic or silicon nitride ceramic.

6. The method for preparing a multifunctional composite layer structure cable material according to claim 1, characterized in that: The pre-processing in step S1 includes: S1.1, soaking the conductive fiber in deionized water for 30 to 60 minutes at a temperature of 20 to 30°C; using an ultrasonic cleaning device to assist in cleaning the conductive fiber at an ultrasonic frequency of 30 to 50 kHz for 10 minutes; S1.2, soaking the conductive fiber in a 20-30% nitric acid solution or a 10-20% sulfuric acid solution by slow stirring for 15-30 minutes at a temperature of 50-70°C; S1.3, take out the conductive fiber, rinse it repeatedly with deionized water until it is neutral, and soak the neutralized conductive fiber in a solution containing 10% silane coupling agent for 50 to 60 minutes at a temperature of 30 to 50°C; S1.4, spraying a layer of nano-silicon dioxide coating on the surface of the conductive fiber, using a spraying device, the spraying temperature is 70-90°C, the coating thickness is controlled at 50nm, and low-temperature plasma treatment is used, specifically using oxygen or argon plasma, the power is 100W, the treatment time is 5min, and a microscopic rough structure is formed on the surface of the nano-silicon dioxide coating; S1.5 Spread the treated conductive fibers evenly on a drying plate, place in a drying oven, dry at 60-80°C for 2-4 hours, and cool to room temperature after drying.

7. The method for preparing a multifunctional composite layer structure cable material according to claim 1, characterized in that: Step S2 includes: S2.1, the pretreated conductive fiber and the insulating polymer are mixed in proportion, N, N-dimethylformamide or dimethyl sulfoxide solvent is added for dilution, the mass ratio of the solvent to the total solid is (60-70): (30-40), a high-speed disperser is used to stir at a speed of 5000r / min for 20-40min, and an ultrasonic dispersion device is set to a frequency of 30-50kHz and a power of 200W to treat the mixture for 15min to form a mixed slurry; S2.2, placing the substrate in a cleaning tank, cleaning the surface with isopropyl alcohol, and after cleaning, placing the substrate in a plasma cleaning machine, using oxygen plasma for 5 min at a power of 100 W to enhance the hydrophilicity and adhesion of the substrate surface; S2.3, fix the pretreated substrate on the vacuum chuck of the spin coater, ensure that its surface is flat and free of bubbles, use a dropper to evenly drip the mixed slurry on the center of the substrate, the dripping amount is 0.5 ml per square centimeter, start the spin coater, rotate at a speed of 500 r / min for 10 seconds in the first stage to evenly spread the slurry; rotate at a speed of 2000 r / min for 30 seconds in the second stage to form a uniform coating, and remove excess slurry; S2.4, during the spin coating process, an electrostatic field-assisted technology is introduced, by providing a high voltage electrode below the substrate and a grounded metal mesh above the substrate to form an electrostatic field, and by adjusting the intensity and direction of the electrostatic field, the microstructure of the coating is optimized; S2.

5. Transfer the coated substrate to a hot press, control the pressure to 5 MPa, and control the temperature through a program. Preheat at 100° C. for 10 min, then heat to 150-200° C. for curing, and the duration is 30 min.

8. The method for preparing a multifunctional composite layer structure cable material according to claim 7, characterized in that: In step S2.4, the electrostatic field assisted technology is specifically as follows: by fine-tuning the distance between the high-voltage electrode and the substrate within the range of 5 to 20 mm, and regulating the voltage between 3 and 7 kV, the magnitude of the electrostatic field strength can be changed; at the same time, a plurality of lateral electrodes that can independently apply potentials are arranged around the substrate, so that the electric field is inclined in a specific direction or distributed in a surrounding manner; a mechanical fine-tuning mechanism that can be precisely positioned is provided on the electrode mounting bracket, and the direction of the electric field is further refined and controlled by adjusting the rotation angle.

9. The method for preparing a multifunctional composite layer structure cable material according to claim 1, characterized in that: In step S3, the lamination technology is 30-50 kg / cm 2 The pressure is 100-200°C and the temperature is between 150°C and 180°C. Double-sided heated pressing rollers are used for continuous pressing for 30 seconds. Ultrasonic vibration is introduced during the pressing process with a frequency of 30-50kHz to promote a more uniform dispersion of the nanofiller. In step S4, the spraying method is to spray the mixed solution at a constant air pressure of 0.2 MPa through a high-precision atomizing nozzle at 40-60° C., and apply a weak electric field of 1 kV in the direction of the substrate plane to align the droplets and optimize the distribution of the function enhancement layer; In step S5, the immersion process is to slowly immerse the substrate into a solution containing weather-resistant polymer materials and micron-sized hollow spherical particles at an immersion speed of 1 mm / s, and promote the uniform distribution of the particles inside the coating through ultrasonic oscillation of 30 to 40 kHz to form an external protective layer with a microporous structure and excellent weather resistance, wherein the micron-sized hollow spherical particles include one or more of hollow alumina, hollow silica, hollow polystyrene, hollow polyacrylate and hollow polyimide microspheres.

10. A multifunctional composite layer structure cable material, characterized in that: The multifunctional composite layer structure cable material is prepared by the preparation method of any one of claims 1 to 9, wherein the multifunctional composite layer structure cable material comprises a substrate, a conductive layer, a protective composite layer, a function enhancement layer and an external protective layer stacked in sequence.