Production method of control cable with double-layer shielding structure

Abstract

The invention discloses a production method of a control cable with a double-layer shielding structure, and belongs to the technical field of cable preparation. The production method of the control cable with the double-layer shielding structure comprises the following steps: step 1, carrying out wire drawing treatment on a copper rod to obtain a conductor material; 2, mixing a dielectric regulator and crosslinked polyethylene to obtain an insulating layer material; step 3, mixing a composite shielding agent with an epoxy resin-based conductive adhesive, coating the surface of an aluminum foil with the mixture, performing hot-pressing compounding with a polyester film to obtain a first shielding layer material, and mixing and braiding tinned copper wires with nickel-coated graphene fibers to obtain a second shielding layer material; and 4, wrapping the surface of the conductor material with the insulating layer material, then sequentially wrapping the first shielding layer material and the second shielding layer material, then wrapping the polyurethane material, and performing embossing to obtain the control cable with the double-layer shielding structure. The cable prepared by the method has high dielectric constant, excellent shielding performance, mechanical performance and thermal stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of cable preparation, and particularly relates to a production method of a double-layer shielded control cable. Background Art

[0002] In the 1950s, along with the start of China's industrialization, the shielded cable industry formed a preliminary industrial chain through technology introduction. After decades of development, a complete system covering raw materials, manufacturing, and applications has been established. Since the 21st century, the expansion of national infrastructure construction and the upgrading of the communication and power sectors have given rise to a large-scale demand for anti-interference cables, promoting the transformation of double-layer shielding technology from the laboratory to wide application.

[0003] In terms of application scenarios, double-layer shielded cables have become the preferred solution for critical infrastructure: in the power system, they are relied on to build anti-interference power transmission lines to ensure the stable operation of smart grids; in 5G communication base stations, such cables are used to achieve low-loss signal transmission to meet high-frequency broadband communication requirements; in the field of industrial control, such as flexible servo motor systems, they rely on the double shielding layer to resist interference in complex electromagnetic environments and ensure nanoscale control accuracy. Medical imaging equipment and aerospace electronic systems also use such cables to transmit high-fidelity signals, and their broadband response characteristics can minimize signal attenuation to the greatest extent.

[0004] Patent CN221125609U discloses a double-layer shielded control cable, which relates to the technical field of wire and cable. It includes multiple main cores and one neutral core; for multiple main cores and one neutral core, an insulating layer and a first shielding layer are respectively extruded in sequence. Multiple main cores and one neutral core located in the center are concentrically stranded, and conductive rubber is extruded between the stranded gaps to form a cable core. A calcium silicate fiber layer, a flame retardant layer, a second shielding layer, and a polyvinyl chloride insulating outer sheath are sequentially arranged outside the cable core layer; the first shielding layer is a wrapped semiconductor paper tape, and the second shielding layer is a wrapped aluminum foil fiber composite cloth. The cable prepared by this invention takes into account both electromagnetic shielding and fire and flame retardance. However, there is still room for improvement in the shielding effect, mechanical properties, and dielectric regulation effect of the cable prepared by this method. Summary of the Invention

[0005] The purpose of the present invention is to provide a production method of a double-layer shielded control cable to solve the technical problems of poor shielding effect, mechanical properties, and dielectric regulation effect of the cable in the prior art.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions: The present invention provides a production method of a double-layer shielded control cable, including the following steps: Step 1: Draw the copper rod, then perform annealing treatment, and then perform surface cleaning and drying to obtain conductor materials; Step 2: Add the dielectric regulator and cross-linked polyethylene into a twin-screw compounding machine, extrude, cool, and shape to obtain the insulating layer material; Step 3: Add the composite shielding agent into the epoxy resin-based conductive adhesive, evenly coat it on the surface of the aluminum foil, and then perform hot pressing and lamination with the polyester film through a hot pressing laminator to obtain the first shielding layer material. Mix tin-plated copper wires and nickel-coated graphene fibers, and then perform weaving to obtain the second shielding layer material; Step 4: Tightly wrap the insulating layer material on the surface of the conductor material, then sequentially wrap the first shielding layer material and the second shielding layer material, and then wrap the polyurethane material, and emboss to obtain the double-layer shielded structure control cable.

[0007] Preferably, in Step 1, the initial diameter of the copper rod is 8 - 12 mm, the drawing speed is 20 - 50 m / min. During the annealing process, in a nitrogen-protected annealing furnace, heat up at a heating rate of 10 - 15 °C / min to 420 - 480 °C, hold for 30 - 60 min, then cool with water, and sequentially clean the surface with a 5 wt% citric acid solution and deionized water.

[0008] Preferably, in Step 2, the dosage ratio of the dielectric regulator to cross-linked polyethylene is (1 - 3) g : (70 - 80) g, the rotation speed of the twin-screw compounding machine is 200 - 400 rpm, the temperature is 150 - 180 °C, the extrusion pressure is 15 - 25 MPa, the extrusion speed is 10 - 30 m / min, and it is cooled in three-stage gradient. The first stage is 60 - 80 °C, the second stage is 40 - 50 °C, and the third stage is 20 - 25 °C.

[0009] Preferably, the preparation method of the dielectric regulator includes the following steps: Q1: Add polyvinylidene fluoride into a container filled with N,N-dimethylacetamide, heat and stir to mix to obtain Solution 1. Sequentially add cuprous chloride, pentamethyldiethylenetriamine, and ethyl methacrylate into Solution 1. After evacuating and introducing nitrogen, heat up and stir to react. After the reaction ends, dilute, precipitate, filter by suction, dissolve, precipitate, wash, and dry to obtain Monomer 1; Q2: Add isooctyl acrylate, Monomer 1, and polyurethane acrylate into a container, ultrasonically mix, then add a photoinitiator, continue ultrasonic stirring, then add distilled water for stirring, irradiate, wash, dry, and grind to obtain the dielectric regulator.

[0010] In the above process, polyvinylidene fluoride is first dissolved by heating in N,N-dimethylacetamide, and a complex is formed using a catalytic system of cuprous chloride / pentamethyldiethylenetriamine to initiate the homolytic cleavage of the C-F bond in polyvinylidene fluoride to generate macromolecular free radicals. Subsequently, ethyl methacrylate monomer is polymerized to obtain monomer 1. Then, monomer 1, isooctyl acrylate, and polyurethane acrylate undergo a cross-linking reaction in the presence of a photoinitiator to obtain a dielectric regulator.

[0011] Preferably, in Q1, the dosage ratio of polyvinylidene fluoride, N,N-dimethylacetamide, cuprous chloride, pentamethyldiethylenetriamine, and ethyl methacrylate is (5 - 7.5) g : (40 - 60) mL : (0.04 - 0.07) g : (0.08 - 0.13) g : (28 - 33) g; in Q2, the dosage ratio of isooctyl acrylate, monomer 1, polyurethane acrylate, photoinitiator, and distilled water is (0.63 - 0.85) g : (0.2 - 0.4) g : (1 - 1.5) g : (0.054 - 0.06) g : (60 - 80) mL.

[0012] Preferably, the preparation method of the composite shielding agent includes the following steps: S1: Add 4-nitrobenzaldehyde and acetic acid to propionic acid, heat and stir, then slowly add pyrrole, heat under reflux for reaction. After the reaction is completed, perform vacuum filtration, washing to obtain a solid. Then mix the solid with pyrrole, heat under reflux, refrigerate, wash, and perform vacuum drying to obtain intermediate A; add intermediate A to hydrochloric acid, introduce nitrogen, then add stannous chloride, stir at room temperature, heat and stir under reflux, cool, refrigerate, filter, dissolve, adjust the pH, and purify to obtain intermediate B; S2: Add intermediate B and sodium acetate to a mixed solution of chlorobenzene and N,N-dimethylformamide, stir and mix, then add cobalt acetate. Under a nitrogen atmosphere, stir and reflux for reaction, then add ultrapure water, filter, and dry to obtain intermediate C; add carbon nanotubes to a mixed solution of concentrated sulfuric acid and concentrated nitric acid, stir magnetically, then perform ice bath ultrasonic stirring, and then slowly add it to distilled water, centrifuge, adjust the pH, perform rotary evaporation, and freeze-dry to obtain carboxylated carbon nanotubes; S3: Add carboxylated carbon nanotubes to distilled water, perform ultrasonic treatment to obtain a mixed solution. Sequentially add EDC and NHS to the mixed solution, stir at room temperature, adjust the pH, then add intermediate C and triethylamine, and react under nitrogen protection by heating. After the reaction is completed, centrifuge, wash, and dry to obtain the composite shielding agent.

[0013] In the above process, under acidic conditions, the aldehyde group of 4-nitrobenzaldehyde condenses with the α-hydrogen of pyrrole to obtain intermediate A. Subsequently, the nitro group of intermediate A is reduced to an amino group by stannous chloride to obtain intermediate B. Then, intermediate B undergoes a coordination reaction with cobalt acetate to obtain intermediate C. Carboxyl groups are introduced onto the surface of carbon nanotubes through strong oxidation. Subsequently, stable NHS esters are formed in the presence of EDC / NHS. Finally, in the presence of triethylamine as a catalyst, the amino group of intermediate C reacts with the NHS ester to form an amide bond, obtaining the composite shielding agent. Among them, the synthesis reaction formula of intermediate C is as follows:

[0014] The results of mass spectrometry analysis of intermediate A are: m / z: 794.19 (100.0%), 795.19 (48.2%), 796.19 (14.3%), 795.18 (3.0%), 797.20 (1.8%), 797.19 (1.2%); the results of mass spectrometry analysis of intermediate B are: m / z: 674.29 (100.0%), 675.29 (50.5%), 676.30 (11.3%), 677.30 (1.7%), 676.29 (1.4%); the results of mass spectrometry analysis of intermediate C are: m / z: 365.60 (100.0%), 366.10 (50.9%), 366.60 (12.5%), 367.11 (1.7%).

[0015] Preferably, in S1, the dosage ratio of 4-nitrobenzaldehyde, acetic acid and pyrrole is (10 - 12.2) g : (10 - 15) mL : (4.5 - 5.6) mL, and the dosage ratio of the solid and pyrrole is (4 - 5.3) g : (32 - 40) mL; the dosage ratio of intermediate A, hydrochloric acid and stannous chloride is (1.7 - 2.5) g : (130 - 180) mL : (8 - 9.3) g.

[0016] Preferably, in S2, the dosage ratio of intermediate B, sodium acetate, chlorobenzene, N,N-dimethylformamide and cobalt acetate is (0.24 - 0.35) g : (0.158 - 0.167) g : (30 - 60) mL : (25 - 36) mL : (0.42 - 0.57) g; the dosage ratio of carbon nanotubes, concentrated sulfuric acid and concentrated nitric acid is (1 - 2) g : (60 - 80) mL : (20 - 30) mL.

[0017] Preferably, in S3, the dosage ratio of carboxylated carbon nanotubes, EDC, NHS, intermediate C and triethylamine is (1 - 1.4) g : (1.2 - 1.6) g : (0.4 - 0.6) g : (8 - 10.2) g : (0.1 - 0.14) g.

[0018] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows: 1. First, the present invention uses polyvinylidene fluoride, ethyl methacrylate, isooctyl acrylate, and polyurethane acrylate as the main raw materials to prepare a dielectric regulator. Subsequently, 4-nitrobenzaldehyde, pyrrole, stannous chloride, cobalt acetate, and carbon nanotubes are used as the main raw materials to prepare a composite shielding agent. Adding the dielectric regulator and the composite shielding agent to the cable manufacturing process can effectively improve its dielectric constant, shielding performance, mechanical properties, and thermal stability.

[0019] 2. Adding the prepared dielectric regulator to the cable manufacturing process can effectively improve the dielectric constant, mechanical properties, and thermal stability of the cable.

[0020] 3. Adding the prepared composite shielding agent to the cable manufacturing process can effectively improve the electromagnetic shielding performance, mechanical properties, and thermal stability of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 It is a schematic cross-sectional view of a double-layer shielded structure control cable prepared by the present invention.

[0023] BRIEF DESCRIPTION OF THE DRAWINGS: 1. Conductor; 2. Insulation layer; 3. First shielding layer; 4. Second shielding layer; 5. Polyurethane layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0025] Example 1: Refer to Figure 1As shown in the figure, the double-layer shielded control cable of this embodiment includes a conductor 1, an insulating layer 2, a first screen shielding layer 3, a second shielding layer 4, and a polyurethane layer 5 arranged in sequence from the inside to the outside. There are multiple conductors, preferably three, which are tightly combined by circular array. The periphery of the conductor 1 is tightly wrapped with an insulating layer 2. The outside of the insulating layer 2 is wrapped with a first shielding layer 3. The outside of the first shielding layer 3 is wrapped with a second shielding layer 4. The outside of the second shielding layer 4 is wrapped with a layer of polyurethane layer 5.

[0026] Example 2: This embodiment discloses a preparation method of a dielectric regulator, which includes the following steps: Q1: Add 6.25 g of polyvinylidene fluoride into a container containing 50 mL of N,N-dimethylacetamide, heat and stir at 60 °C and 300 rpm to obtain solution 1. Add 0.055 g of cuprous chloride, 0.1 g of pentamethyldiethylenetriamine, and 30 g of ethyl methacrylate into solution 1 in sequence. After evacuating and introducing nitrogen, raise the temperature to 100 °C and stir and react at 800 rpm for 2 h. After the reaction, dilute with tetrahydrofuran, precipitate with methanol, filter by suction, dissolve in N,N-dimethylacetamide, precipitate, wash, and dry to obtain monomer 1; Q2: Add 0.74 g of isooctyl acrylate, 0.3 g of monomer 1, and 1.25 g of polyurethane acrylate into a container, ultrasonically mix for 20 min, then add 0.058 g of photoinitiator, continue to ultrasonically stir for 5 min, then add 70 mL of distilled water and stir for 20 min, irradiate for 8 min, wash with ethanol, dry, grind to obtain a dielectric regulator.

[0027] This embodiment discloses a preparation method of a composite shielding agent, which includes the following steps: S1: Add 11.1 g of 4-nitrobenzaldehyde and 12.5 mL of acetic acid into 300 mL of propionic acid, heat and stir at 140 °C, then slowly add 4.9 mL of pyrrole, heat and reflux at 155 °C for 30 min. After the reaction, filter by vacuum suction, wash with distilled water and methanol until neutral to obtain a solid. Then mix 4.6 g of the solid with 36 mL of pyrrole, heat and reflux at 120 °C for 1 h, refrigerate for 12 h, wash with acetone, and dry in vacuum to obtain intermediate A; Add 2.1 g of intermediate A into 155 mL of hydrochloric acid, introduce nitrogen, then add 8.6 g of stannous chloride, stir at room temperature for 2.5 h, heat and stir and reflux at 80 °C for 30 min, cool, refrigerate for 12 h, filter, dissolve, adjust the pH, purify to obtain intermediate B; S2: Add 0.29 g of intermediate B and 0.163 g of sodium acetate into a mixed solution of 45 mL of chlorobenzene and 31 mL of N,N-dimethylformamide. After stirring and mixing, add 0.48 g of cobalt acetate. Under a nitrogen atmosphere, stir and reflux for 48 h, then add ultrapure water, filter, and dry to obtain intermediate C; add 1.5 g of carbon nanotubes into a mixed solution of 70 mL of concentrated sulfuric acid and 25 mL of concentrated nitric acid, magnetically stir for 1 h, then stir ultrasonically in an ice bath for 10 min, and then slowly add it into distilled water, centrifuge, adjust the pH to 7, rotary evaporate, and freeze-dry to obtain carboxylated carbon nanotubes; S3: Add 1.2 g of carboxylated carbon nanotubes into 100 mL of distilled water, ultrasonically treat for 10 min to obtain a mixed solution. Sequentially add 1.4 g of EDC and 0.5 g of NHS into the mixed solution, stir at room temperature, adjust the pH to 7, then add 9.1 g of intermediate C and 0.12 g of triethylamine, heat and react under nitrogen protection. After the reaction, centrifuge, wash, and dry to obtain the composite shielding agent.

[0028] This example discloses a production method of a double-layer shielded structure control cable, including the following steps: Step 1: Perform wire drawing on a copper rod with an initial diameter of 12 mm at a wire drawing speed of 20 m / min, and then perform annealing treatment. In a nitrogen-protected annealing furnace, heat up at a heating rate of 12 °C / min to 450 °C, hold for 45 min, then cool with water, and then perform surface cleaning. Sequentially clean the surface with a 5 wt% citric acid solution and deionized water, and dry to obtain the conductor material; Step 2: Add 2 g of dielectric regulator and 75 g of cross-linked polyethylene into a twin-screw compounding machine. The rotation speed of the twin-screw compounding machine is 300 rpm, the temperature is 160 °C, extrude at an extrusion speed of 20 m / min and an extrusion pressure of 20 MPa, and cool in three-stage gradients. The first stage is 70 °C, the second stage is 45 °C, and the third stage is 25 °C for shaping to obtain the insulating layer material; Step 3: Add the composite shielding agent into the epoxy resin-based conductive adhesive, uniformly coat it on the surface of the aluminum foil, and then perform hot pressing and compounding with the polyester film through a hot pressing compounding machine to obtain the first shielding layer material. Mix and braid tinned copper wires and nickel-coated graphene fibers, and then perform braiding to obtain the second shielding layer material; Step 4: Tightly wrap the insulating layer material on the surface of the conductor material, then sequentially wrap the first shielding layer material and the second shielding layer material, and then wrap the polyurethane material and emboss to obtain the double-layer shielded structure control cable.

[0029] Example 3: This example discloses a preparation method of a dielectric regulator, including the following steps: Q1: Add 5 g of polyvinylidene fluoride into a container containing 40 mL of N,N-dimethylacetamide, heat and stir the mixture at 60 °C and 300 rpm to obtain Solution 1. Then, add 0.04 g of copper chloride, 0.08 g of pentamethyldiethylenetriamine and 28 g of ethyl methacrylate into Solution 1 in sequence. After evacuating and introducing nitrogen, raise the temperature to 100 °C and stir and react at 800 rpm for 2 h. After the reaction, dilute with tetrahydrofuran, precipitate with methanol, filter by suction, dissolve in N,N-dimethylacetamide, precipitate, wash and dry to obtain Monomer 1; Q2: Add 0.63 g of isooctyl acrylate, 0.2 g of Monomer 1 and 1.5 g of polyurethane acrylate into a container, ultrasonically mix for 20 min, then add 0.054 g of photoinitiator, continue to ultrasonically stir for 5 min, then add 80 mL of distilled water and stir for 20 min, irradiate for 8 min, wash with ethanol, dry and grind to obtain a dielectric regulator.

[0030] This example discloses a preparation method of a composite shielding agent, including the following steps: S1: Add 10 g of 4-nitrobenzaldehyde and 15 mL of acetic acid into 300 mL of propionic acid, heat and stir at 140 °C, then slowly add 5.6 mL of pyrrole, heat and reflux at 155 °C for 30 min. After the reaction, filter by vacuum suction, wash with distilled water and methanol until neutral to obtain a solid. Then, mix 4 g of the solid with 40 mL of pyrrole, heat and reflux at 120 °C for 1 h, refrigerate for 12 h, wash with acetone and dry under vacuum to obtain Intermediate A; Add 1.7 g of Intermediate A into 130 mL of hydrochloric acid, introduce nitrogen and then add 9.3 g of stannous chloride, stir at room temperature for 2.5 h, heat and stir at 80 °C for reflux for 30 min, cool, refrigerate for 12 h, filter, dissolve, adjust the pH, purify to obtain Intermediate B; S2: Add 0.24 g of Intermediate B and 0.158 g of sodium acetate into a mixed solution of 60 mL of chlorobenzene and 25 mL of N,N-dimethylformamide, stir and mix, then add 0.42 g of cobalt acetate, under a nitrogen atmosphere, stir and reflux for 48 h, then add ultrapure water, filter and dry to obtain Intermediate C; Add 1 g of carbon nanotubes into a mixed solution of 60 mL of concentrated sulfuric acid and 30 mL of concentrated nitric acid, stir magnetically for 1 h, then stir ultrasonically in an ice bath for 10 min, then slowly add it into distilled water, centrifuge, adjust the pH = 7, rotary evaporate and freeze-dry to obtain carboxylated carbon nanotubes; S3: Add 1.4 g of carboxylated carbon nanotubes to 100 mL of distilled water, ultrasonically treat for 10 min to obtain a mixed solution. Sequentially add 1.6 g of EDC and 0.4 g of NHS to the mixed solution, stir at room temperature, adjust the pH to 7, then add 10.2 g of intermediate C and 0.1 g of triethylamine, heat and react under nitrogen protection. After the reaction, centrifuge, wash, and dry to obtain a composite shielding agent.

[0031] This embodiment discloses a production method of a double-layer shielded structure control cable, including the following steps: Step 1: Perform wire drawing on a copper rod with an initial diameter of 12 mm at a wire drawing speed of 20 m / min, and then perform annealing treatment. In a nitrogen-protected annealing furnace, heat up to 450 °C at a heating rate of 12 °C / min, keep warm for 45 min and then cool with water. Subsequently, perform surface cleaning, sequentially clean the surface with a 5 wt% citric acid solution and deionized water, and dry to obtain a conductor material. Step 2: Add 1 g of a dielectric regulator and 80 g of cross-linked polyethylene to a twin-screw compounding machine. The rotation speed of the twin-screw compounding machine is 300 rpm, the temperature is 160 °C, extrude at an extrusion speed of 20 m / min and an extrusion pressure of 20 MPa, and cool in three-stage gradients. The first stage is 70 °C, the second stage is 45 °C, and the third stage is 25 °C, and shape to obtain an insulating layer material. Step 3: Add the composite shielding agent to an epoxy resin-based conductive adhesive, evenly coat it on the surface of the aluminum foil, and then perform hot pressing and compounding with a polyester film through a hot pressing compounding machine to obtain a first shielding layer material. Mix tin-plated copper wires and nickel-coated graphene fibers and then perform braiding to obtain a second shielding layer material. Step 4: Tightly wrap the insulating layer material on the surface of the conductor material, then sequentially wrap the first shielding layer material and the second shielding layer material, and then wrap a polyurethane material and emboss to obtain a double-layer shielded structure control cable.

[0032] Example 4: This embodiment discloses a preparation method of a dielectric regulator, including the following steps: Q1: Add 7.5 g of polyvinylidene fluoride to a container containing 60 mL of N,N-dimethylacetamide, heat and stir and mix at 60 °C and 300 rpm to obtain solution 1. Sequentially add 0.07 g of copper chloride, 0.13 g of pentamethyldiethylenetriamine, and 33 g of ethyl methacrylate to solution 1. After evacuating and introducing nitrogen, raise the temperature to 100 °C and stir and react at 800 rpm for 2 h. After the reaction, dilute with tetrahydrofuran, precipitate with methanol, filter by suction, dissolve in N,N-dimethylacetamide, precipitate, wash, and dry to obtain monomer 1. Q2: Add 0.85 g of isooctyl acrylate, 0.4 g of monomer 1, and 1 g of polyurethane acrylate into a container, ultrasonically mix for 20 min, then add 0.06 g of photoinitiator, continue ultrasonic stirring for 5 min, then add 60 mL of distilled water and stir for 20 min, irradiate for 8 min, wash with ethanol, dry, and grind to obtain a dielectric regulator.

[0033] This example discloses a preparation method of a composite shielding agent, including the following steps: S1: Add 12.2 g of 4-nitrobenzaldehyde and 10 mL of acetic acid into 300 mL of propionic acid, heat and stir at 140 °C, then slowly add 4.5 mL of pyrrole, heat and reflux at 155 °C for 30 min. After the reaction is completed, perform vacuum filtration, wash with distilled water and methanol until neutral to obtain a solid. Then mix 5.3 g of the solid with 32 mL of pyrrole, heat and reflux at 120 °C for 1 h, refrigerate for 12 h, wash with acetone, and vacuum dry to obtain intermediate A; Add 2.5 g of intermediate A into 180 mL of hydrochloric acid, introduce nitrogen gas, then add 8 g of stannous chloride, stir at room temperature for 2.5 h, heat and stir under reflux at 80 °C for 30 min, cool, refrigerate for 12 h, filter, dissolve, adjust the pH, and purify to obtain intermediate B; S2: Add 0.35 g of intermediate B and 0.167 g of sodium acetate into a mixed solution of 30 mL of chlorobenzene and 36 mL of N,N-dimethylformamide, stir and mix, then add 0.57 g of cobalt acetate. Under a nitrogen atmosphere, stir and reflux for 48 h, then add ultrapure water, filter, and dry to obtain intermediate C; Add 2 g of carbon nanotubes into a mixed solution of 80 mL of concentrated sulfuric acid and 20 mL of concentrated nitric acid, magnetically stir for 1 h, then perform ice bath ultrasonic stirring for 10 min, then slowly add it into distilled water, centrifuge, adjust the pH = 7, rotary evaporate, and freeze dry to obtain carboxylated carbon nanotubes; S3: Add 1 g of carboxylated carbon nanotubes into 100 mL of distilled water, ultrasonically treat for 10 min to obtain a mixed solution. Sequentially add 1.2 g of EDC and 0.6 g of NHS into the mixed solution, stir at room temperature, adjust the pH = 7, then add 8 g of intermediate C and 0.14 g of triethylamine, and heat and react under nitrogen protection. After the reaction is completed, centrifuge, wash, and dry to obtain the composite shielding agent.

[0034] This example discloses a production method of a double-layer shielding structure control cable, including the following steps: Step 1: The copper rod with an initial diameter of 12 mm is drawn at a drawing speed of 20 m / min, and then annealed. In a nitrogen-protected annealing furnace, it is heated to 450 °C at a heating rate of 12 °C / min, held for 45 min, and then water-cooled. Subsequently, surface cleaning is carried out, and the surface is cleaned successively with a 5 wt% citric acid solution and deionized water, and then dried to obtain the conductor material; Step 2: 3 g of the dielectric regulator and 70 g of cross-linked polyethylene are added to a twin-screw compounding machine. The rotational speed of the twin-screw compounding machine is 300 rpm, the temperature is 160 °C, extrusion is carried out, the extrusion speed is 20 m / min, the extrusion pressure is 20 MPa, and it is cooled in three-stage gradients. The first stage is 70 °C, the second stage is 45 °C, and the third stage is 25 °C for shaping to obtain the insulating layer material; Step 3: The composite shielding agent is added to the epoxy resin-based conductive adhesive, evenly coated on the surface of the aluminum foil, and then hot-pressed and compounded with the polyester film through a hot-pressing compounding machine to obtain the first shielding layer material. The tinned copper wire is mixed and braided with nickel-coated graphene fibers, and then braided to obtain the second shielding layer material; Step 4: The insulating layer material is tightly wrapped on the surface of the conductor material, and then the first shielding layer material and the second shielding layer material are successively wrapped, and then the polyurethane material is wrapped and embossed to obtain the double-layer shielded structure control cable.

[0035] Example 5: This example discloses a preparation method of a dielectric regulator, including the following steps: Q1: 5.5 g of polyvinylidene fluoride is added to a container containing 45 mL of N,N-dimethylacetamide, and heated and stirred at 60 °C and 300 rpm to obtain Solution 1. 0.05 g of copper chloride, 0.09 g of pentamethyldiethylenetriamine, and 29 g of ethyl methacrylate are successively added to Solution 1. After evacuating and introducing nitrogen, the temperature is raised to 100 °C, and stirred and reacted at 800 rpm for 2 h. After the reaction, it is diluted with tetrahydrofuran, precipitated with methanol, filtered by suction, dissolved in N,N-dimethylacetamide, precipitated, washed, and dried to obtain Monomer 1; Q2: 0.68 g of isooctyl acrylate, 0.25 g of Monomer 1, and 1.1 g of polyurethane acrylate are added to a container, ultrasonically mixed for 20 min, then 0.057 g of photoinitiator is added, and ultrasonically stirred for another 5 min. Then 65 mL of distilled water is added and stirred for 20 min, irradiated for 8 min, washed with ethanol, dried, and ground to obtain the dielectric regulator.

[0036] This example discloses a preparation method of a composite shielding agent, including the following steps: S1: Add 10.5 g of 4-nitrobenzaldehyde and 11 mL of acetic acid to 300 mL of propionic acid, heat and stir at 140 °C, then slowly add 4.7 mL of pyrrole, heat under reflux at 155 °C for 30 min. After the reaction is completed, perform vacuum filtration, wash with distilled water and methanol until neutral to obtain a solid. Then mix 4.3 g of the solid with 34 mL of pyrrole, heat under reflux at 120 °C for 1 h, refrigerate for 12 h, wash with acetone, and dry under vacuum to obtain intermediate A; Add 2.3 g of intermediate A to 140 mL of hydrochloric acid, introduce nitrogen, then add 8.3 g of stannous chloride, stir at room temperature for 2.5 h, heat and stir under reflux at 80 °C for 30 min, cool, refrigerate for 12 h, filter, dissolve, adjust the pH, and purify to obtain intermediate B; S2: Add 0.27 g of intermediate B and 0.160 g of sodium acetate to a mixed solution of 40 mL of chlorobenzene and 28 mL of N,N-dimethylformamide, stir and mix, then add 0.46 g of cobalt acetate. Under a nitrogen atmosphere, stir and reflux for 48 h, then add ultrapure water, filter, and dry to obtain intermediate C; Add 1.2 g of carbon nanotubes to a mixed solution of 65 mL of concentrated sulfuric acid and 22 mL of concentrated nitric acid, stir magnetically for 1 h, then stir ultrasonically in an ice bath for 10 min, and then slowly add it to distilled water, centrifuge, adjust the pH to 7, rotary evaporate, and freeze-dry to obtain carboxylated carbon nanotubes; S3: Add 1.1 g of carboxylated carbon nanotubes to 100 mL of distilled water, ultrasonically treat for 10 min to obtain a mixed solution. Sequentially add 1.3 g of EDC and 0.45 g of NHS to the mixed solution, stir at room temperature, adjust the pH to 7, then add 8.5 g of intermediate C and 0.11 g of triethylamine, and heat the reaction under nitrogen protection. After the reaction is completed, centrifuge, wash, and dry to obtain the composite shielding agent.

[0037] This example discloses a production method of a double-layer shielded structure control cable, including the following steps: Step 1: Perform wire drawing on a copper rod with an initial diameter of 12 mm at a wire drawing speed of 20 m / min, and then perform annealing treatment. In a nitrogen-protected annealing furnace, heat up to 450 °C at a heating rate of 12 °C / min, hold for 45 min, then cool with water. Subsequently, perform surface cleaning, sequentially clean the surface with a 5 wt% citric acid solution and deionized water, and dry to obtain the conductor material; Step 2: Add 1.5 g of dielectric regulator and 72 g of cross-linked polyethylene to a twin-screw mixer. The rotation speed of the twin-screw mixer is 300 rpm, the temperature is 160 °C, extrude at an extrusion speed of 20 m / min and an extrusion pressure of 20 MPa, and cool in three-stage gradients, the first stage is 70 °C, the second stage is 45 °C, the third stage is 25 °C, and shape to obtain the insulating layer material; Step 3: Add the composite shielding agent to the epoxy resin-based conductive adhesive, evenly coat it on the surface of the aluminum foil, and then perform hot pressing and lamination with the polyester film through a hot pressing laminator to obtain the first shielding layer material. Mix tin-plated copper wires and nickel-coated graphene fibers, and then perform weaving to obtain the second shielding layer material; Step 4: Tightly wrap the insulating layer material on the surface of the conductor material, then sequentially wrap the first shielding layer material and the second shielding layer material, and then wrap the polyurethane material and emboss to obtain a double-layer shielded structure control cable.

[0038] Comparative Example 1: Compared with Example 1, in the process of preparing the double-layer shielded structure control cable in Comparative Example 1, no dielectric regulator is added, and other conditions remain unchanged.

[0039] Comparative Example 2: Compared with Example 1, in the process of preparing the double-layer shielded structure control cable in Comparative Example 2, no composite shielding agent is added, and other conditions remain unchanged.

[0040] Experimental Example: Test the performance of the double-layer shielded structure control cables prepared in Examples 2-5 and Comparative Examples 1-2. Test the dielectric properties of the samples according to GB / T 31838.8-2024, test the shielding performance of the samples according to GB / T 14864-2013, test the mechanical properties of the samples according to GB / T 7424.2-2008, and test the temperature resistance performance of the samples according to GB / T2951.14-2008. The test results are shown in Table 1: Table 1 Item Relative dielectric constant Shielding effectiveness Tensile strength / MPa Elongation at break / % Rate of change of tensile strength at 80 °C / % Example 2 7.4 78 dB 67.5 213.7 11.5 Example 3 7.2 76 dB 65.8 212.9 11.8 Example 4 7.2 75 dB 66.3 213.1 12.5 Example 5 7.1 74 dB 67.1 211.6 12.6 Comparative example 1 3.5 74 dB 42.8 176.9 21.8 Comparative example 2 7 56 dB 42.5 177.4 22.3 It can be seen from the test results in Table 1 that the cables prepared in Examples 2-5 of the present invention have excellent dielectric constant, shielding performance, mechanical properties and thermal stability. By comparing Comparative Example 1 with Examples 2-5, it can be seen that adding a dielectric regulator can effectively improve the dielectric constant, mechanical properties and thermal stability of the cable; by comparing Comparative Example 2 with Examples 2-5, it can be seen that adding a composite shielding agent can effectively improve the shielding performance, mechanical properties and thermal stability of the cable.

[0041] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

[0042] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only the specific implementation manners. Obviously, according to the content of this specification, many modifications and variations can be made. These embodiments are selected and specifically described in this specification in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A production method of a double-layer shielded structure control cable, characterized in that, It includes the following steps: Step 1: Draw the copper rod, then perform annealing treatment, and then conduct surface cleaning and drying to obtain the conductor material; Step 2: Add the dielectric regulator and cross-linked polyethylene into a twin-screw mixer, extrude, cool, and shape to obtain the insulating layer material; Step 3: Add the composite shielding agent into the epoxy resin-based conductive adhesive, evenly coat it on the surface of the aluminum foil, and then perform hot pressing and compounding with the polyester film through a hot pressing compounding machine to obtain the first shielding layer material. Mix tin-plated copper wires and nickel-coated graphene fibers, and then perform braiding to obtain the second shielding layer material; Step 4: Tightly wrap the insulating layer material on the surface of the conductor material, then sequentially wrap the first shielding layer material and the second shielding layer material, and then wrap the polyurethane material and emboss to obtain the double-layer shielded structure control cable.

2. The production method of the double-layer shielded structure control cable according to claim 1, characterized in that, In the said Step 1, the initial diameter of the copper rod is 8 - 12 mm, the drawing speed is 20 - 50 m / min. During the annealing treatment, in a nitrogen-protected annealing furnace, heat up at a heating rate of 10 - 15 °C / min to 420 - 480 °C, keep warm for 30 - 60 min and then cool with water. Clean the surface successively with a 5 wt% citric acid solution and deionized water.

3. The production method of the double-layer shielded structure control cable according to claim 1, characterized in that, In the said Step 2, the dosage ratio of the dielectric regulator and cross-linked polyethylene is (1 - 3) g : (70 - 80) g, the rotation speed of the twin-screw mixer is 200 - 400 rpm, the temperature is 150 - 180 °C, the extrusion pressure is 15 - 25 MPa, the extrusion speed is 10 - 30 m / min, and it is cooled in three-stage gradient. The first stage is 60 - 80 °C, the second stage is 40 - 50 °C, and the third stage is 20 - 25 °C.

4. The production method of the double-layer shielded structure control cable according to claim 1, characterized in that, The preparation method of the said dielectric regulator includes the following steps: Q1: Add polyvinylidene fluoride into a container filled with N,N-dimethylacetamide, heat and stir to mix to obtain Solution 1. Add cuprous chloride, pentamethyldiethylenetriamine, and ethyl methacrylate into Solution 1 in sequence. After evacuating and introducing nitrogen, heat up and stir to react. After the reaction ends, dilute, precipitate, filter by suction, dissolve, precipitate, wash, and dry to obtain Monomer 1; Q2: Add isooctyl acrylate, Monomer 1, and polyurethane acrylate into a container, ultrasonically mix, then add a photoinitiator, continue ultrasonic stirring, then add distilled water for stirring, irradiate, wash, dry, and grind to obtain the dielectric regulator.

5. The production method of the double-layer shielded structure control cable according to claim 4, characterized in that, In the said Q1, the dosage ratio of polyvinylidene fluoride, N,N-dimethylacetamide, cuprous chloride, pentamethyldiethylenetriamine, and ethyl methacrylate is (5 - 7.5) g : (40 - 60) mL : (0.04 - 0.07) g : (0.08 - 0.13) g : (28 - 33) g; in the said Q2, the dosage ratio of isooctyl acrylate, Monomer 1, polyurethane acrylate, photoinitiator, and distilled water is (0.63 - 0.85) g : (0.2 - 0.4) g : (1 - 1.5) g : (0.054 - 0.06) g : (60 - 80) mL.

6. The production method of the double-layer shielded structure control cable according to claim 1, characterized in that, The preparation method of the said composite shielding agent includes the following steps: S1: Add 4-nitrobenzaldehyde and acetic acid to propionic acid, heat and stir, then slowly add pyrrole, heat under reflux for reaction. After the reaction is completed, perform vacuum filtration, wash to obtain a solid. Then mix the solid with pyrrole, heat under reflux, refrigerate, wash, and dry under vacuum to obtain intermediate A; Add intermediate A to hydrochloric acid, introduce nitrogen, then add stannous chloride, stir at room temperature, heat and stir under reflux, cool, refrigerate, filter, dissolve, adjust the pH, and purify to obtain intermediate B; S2: Add intermediate B and sodium acetate to a mixed solution of chlorobenzene and N,N-dimethylformamide, stir and mix, then add cobalt acetate. Under a nitrogen atmosphere, stir and reflux for reaction, then add ultrapure water, filter, and dry to obtain intermediate C; Add carbon nanotubes to a mixed solution of concentrated sulfuric acid and concentrated nitric acid, stir magnetically, then perform ice bath ultrasonic stirring, and then slowly add to distilled water, centrifuge, adjust the pH, rotary evaporate, and freeze-dry to obtain carboxylated carbon nanotubes; S3: Add carboxylated carbon nanotubes to distilled water, perform ultrasonic treatment to obtain a mixed solution. Sequentially add EDC and NHS to the mixed solution, stir at room temperature, adjust the pH, then add intermediate C and triethylamine, and react under nitrogen protection by heating. After the reaction is completed, centrifuge, wash, and dry to obtain the composite shielding agent.

7. The production method of the double-layer shielded structure control cable according to claim 6, characterized in that, In the above S1, the dosage ratio of 4-nitrobenzaldehyde, acetic acid, and pyrrole is (10 - 12.2) g : (10 - 15) mL : (4.5 - 5.6) mL, and the dosage ratio of the solid and pyrrole is (4 - 5.3) g : (32 - 40) mL; The dosage ratio of intermediate A, hydrochloric acid, and stannous chloride is (1.7 - 2.5) g : (130 - 180) mL : (8 - 9.3) g.

8. The production method of the double-layer shielded structure control cable according to claim 6, characterized in that, In the above S2, the dosage ratio of intermediate B, sodium acetate, chlorobenzene, N,N-dimethylformamide, and cobalt acetate is (0.24 - 0.35) g : (0.158 - 0.167) g : (30 - 60) mL : (25 - 36) mL : (0.42 - 0.57) g; The dosage ratio of carbon nanotubes, concentrated sulfuric acid, and concentrated nitric acid is (1 - 2) g : (60 - 80) mL : (20 - 30) mL.

9. The production method of the double-layer shielded structure control cable according to claim 6, characterized in that, In the above S3, the dosage ratio of carboxylated carbon nanotubes, EDC, NHS, intermediate C, and triethylamine is (1 - 1.4) g : (1.2 - 1.6) g : (0.4 - 0.6) g : (8 - 10.2) g : (0.1 - 0.14) g.

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