Method for producing a double shielded structure control cable

Abstract

The application discloses a production method of a double-layer shielding structure control cable and belongs to the technical field of cable preparation. The production method of the double-layer shielding structure control cable comprises the following steps: step one, performing wire drawing treatment on a copper rod to obtain a conductor material; step two, mixing a dielectric control agent and crosslinked polyethylene to obtain an insulating layer material; step three, mixing a composite shielding agent and an epoxy resin-based conductive adhesive, coating the mixture on the surface of an aluminum foil, performing hot pressing on the aluminum foil and a polyester film to obtain a first shielding layer material, mixing plated tin copper wires and nickel-coated graphene fibers, and weaving to obtain a second shielding layer material; and step four, wrapping the insulating layer material on the surface of the conductor material, then wrapping the first shielding layer material and the second shielding layer material in sequence, and then wrapping polyurethane material, and performing embossing to obtain the double-layer shielding structure control cable. The cable prepared by the method has high dielectric constant, excellent shielding performance, mechanical performance and thermal stability.

Description

Technical Field

[0001] This invention belongs to the field of cable manufacturing technology, specifically relating to a method for producing double-shielded control cables. Background Technology

[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, it has built a complete system covering raw materials, manufacturing, and applications. Since the beginning of the 21st century, the expansion of national infrastructure and the upgrading of the communications and power sectors have spurred a large-scale demand for anti-interference cables, driving double-layer shielding technology from the laboratory to widespread application.

[0003] In application scenarios, double-shielded cables have become the preferred solution for critical infrastructure: power systems rely on them to build interference-resistant transmission lines and ensure the stable operation of smart grids; 5G communication base stations use these cables to achieve low-loss signal transmission, meeting the needs of high-frequency broadband communication; in the field of industrial control, such as flexible servo motor systems, the double shielding layer resists interference in complex electromagnetic environments, ensuring nanometer-level control precision. Medical imaging equipment and aerospace electronic systems also use these cables to transmit high-fidelity signals, as their wideband response characteristics minimize signal attenuation.

[0004] Patent CN221125609U discloses a double-shielded control cable, relating to the field of wire and cable technology. It includes multiple main cores and one center core; the main cores and center core are sequentially extruded with an insulation layer and a first shielding layer, respectively. The main cores and the central center core are concentrically twisted and conductive rubber is extruded between the twisted gaps to form the cable core. Outside the cable core layer, a calcium silicate fiber layer, a flame-retardant layer, a second shielding layer, and a polyvinyl chloride insulating jacket are sequentially provided. 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 achieves both electromagnetic shielding and fire retardancy; 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 this invention is to provide a method for producing a double-shielded control cable, which solves the technical problems of poor shielding effect, mechanical properties and dielectric regulation effect of cables in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a method for producing a double-shielded control cable, comprising the following steps:

[0008] Step 1: The copper rod is drawn into wire, then annealed, and then the surface is cleaned and dried to obtain the conductor material;

[0009] Step 2: Add dielectric modifier and cross-linked polyethylene into a twin-screw mixer, extrude, cool, and shape to obtain the insulating layer material;

[0010] Step 3: Add the composite shielding agent to the epoxy resin-based conductive adhesive, coat it evenly on the surface of the aluminum foil, and then hot-press it with the polyester film through a hot-press laminating machine to obtain the first shielding layer material. Mix tin-plated copper wire with nickel-coated graphene fiber and then weave it to obtain the second shielding layer material.

[0011] Step 4: Tightly wrap the insulation material around the surface of the conductor material, then wrap the first shielding layer material and the second shielding layer material in sequence, and then wrap the polyurethane material. Emboss to obtain a double-shielded control cable.

[0012] Preferably, in step one, the initial diameter of the copper rod is 8-12 mm, the wire drawing speed is 20-50 m / min, and during the annealing process, the temperature is raised to 420-480℃ at a heating rate of 10-15℃ / min in a nitrogen-protected annealing furnace, held for 30-60 min, and then water-cooled. The surface is then cleaned sequentially with 5wt% citric acid solution and deionized water.

[0013] Preferably, in step two, the ratio of dielectric modifier to 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℃, the extrusion pressure is 15-25 MPa, the extrusion speed is 10-30 m / min, and the cooling is carried out in three stages: the first stage is 60-80℃, the second stage is 40-50℃, and the third stage is 20-25℃.

[0014] Preferably, the method for preparing the dielectric modulator includes the following steps:

[0015] Q1: Polyvinylidene fluoride was added to a container containing N,N-dimethylacetamide, and heated and stirred to obtain solution 1. Cuprous chloride, pentamethyldiethylenetriamine and ethyl methacrylate were added to solution 1 in sequence. After evacuating and purging with nitrogen, the mixture was heated and stirred to react. After the reaction was completed, the mixture was diluted, precipitated, filtered, dissolved, precipitated, washed and dried to obtain monomer 1.

[0016] Q2: Add isooctyl acrylate, monomer 1 and polyurethane acrylate to a container, mix ultrasonically, then add photoinitiator, continue ultrasonic stirring, then add distilled water and stir, irradiate, wash, dry, grind to obtain dielectric modifier.

[0017] In the above process, polyvinylidene fluoride is first dissolved by heating in N,N-dimethylacetamide. A complex is formed using a cuprous chloride / pentamethyldiethylenetriamine catalytic system, which initiates homolytic cleavage of the CF bonds in the polyvinylidene fluoride to generate macromolecular free radicals. Subsequently, the polymerization of ethyl methacrylate monomer is initiated to obtain monomer 1. Then, monomer 1, isooctyl acrylate, and polyurethane acrylate undergo a crosslinking reaction in the presence of a photoinitiator to obtain a dielectric modifier.

[0018] Preferably, in Q1, the 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; and in Q2, the 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.

[0019] Preferably, the preparation method of the composite shielding agent includes the following steps:

[0020] S1: 4-Nitrobenzaldehyde and acetic acid were added to propionic acid, heated and stirred, and then pyrrole was slowly added. The mixture was heated to reflux and reacted. After the reaction was completed, the mixture was vacuum filtered, washed, and a solid was obtained. The solid was then mixed with pyrrole, heated to reflux, refrigerated, washed, and vacuum dried to obtain intermediate A. Intermediate A was added to hydrochloric acid, nitrogen gas was introduced, and then stannous chloride was added. The mixture was stirred at room temperature, heated to reflux with stirring, cooled, refrigerated, filtered, dissolved, pH adjusted, and purified to obtain intermediate B.

[0021] 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 the 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 sonicate in an ice bath, then slowly add to distilled water, centrifuge, adjust pH, rotary evaporate, and freeze dry to obtain carboxylated carbon nanotubes;

[0022] S3: Carboxylated carbon nanotubes were added to distilled water and sonicated to obtain a mixed solution. EDC and NHS were added to the mixed solution in sequence, and the solution was stirred at room temperature to adjust the pH. Then, intermediate C and triethylamine were added, and the reaction was carried out under nitrogen protection. After the reaction was completed, the solution was centrifuged, washed, and dried to obtain the composite shielding agent.

[0023] 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. Carbon nanotubes introduce carboxyl groups on their surface through strong oxidation, and then form a stable NHS ester in the presence of EDC / NHS. Finally, under the condition of triethylamine as a catalyst, the amino group of intermediate C reacts with the NHS ester to form an amide bond, yielding a composite shielding agent. The synthesis reaction formula of intermediate C is as follows:

[0024]

[0025] The mass spectrometry analysis results for intermediate A were: 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%); for intermediate B, m / z: 674.29 (100.0%), 675.29 (50.5%), 676.30 (11.3%), 677.30 (1.7%), 676.29 (1.4%); and for intermediate C, m / z: 365.60 (100.0%), 366.10 (50.9%), 366.60 (12.5%), 367.11. (1.7%).

[0026] Preferably, in S1, the ratio of 4-nitrobenzaldehyde, acetic acid and pyrrole is (10-12.2) g: (10-15) mL: (4.5-5.6) mL, the ratio of solid to pyrrole is (4-5.3) g: (32-40) mL, and the ratio of intermediate A, hydrochloric acid and stannous chloride is (1.7-2.5) g: (130-180) mL: (8-9.3) g.

[0027] Preferably, in S2, the 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; and the ratio of carbon nanotubes, concentrated sulfuric acid and concentrated nitric acid is (1-2) g : (60-80) mL : (20-30) mL.

[0028] Preferably, in S3, the 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.

[0029] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0030] 1. This invention first uses polyvinylidene fluoride, ethyl methacrylate, isooctyl acrylate and polyurethane acrylate as main raw materials to prepare a dielectric modifier. Then, it uses 4-nitrobenzaldehyde, pyrrole, stannous chloride, cobalt acetate and carbon nanotubes as main raw materials to prepare a composite shielding agent. Adding the dielectric modifier and the composite shielding agent to the cable manufacturing process can effectively improve its dielectric constant, shielding performance, mechanical properties and thermal stability.

[0031] 2. The dielectric modifier prepared in this invention is added to the cable manufacturing process, which can effectively improve the dielectric constant, mechanical properties and thermal stability of the cable.

[0032] 3. The present invention adds the prepared composite shielding agent to the cable manufacturing process, which can effectively improve the electromagnetic shielding performance, mechanical properties and thermal stability of the cable. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a cross-sectional schematic diagram of the double-shielded control cable prepared according to the present invention.

[0035] Figure descriptions: 1. Conductor; 2. Insulating layer; 3. First shielding layer; 4. Second shielding layer; 5. Polyurethane layer. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1: See Figure 1As shown, the double-shielded control cable of this embodiment includes a conductor 1, an insulation layer 2, a first shielding layer 3, a second shielding layer 4, and a polyurethane layer 5 arranged sequentially from the inside to the outside. There are multiple conductors, preferably three, which are tightly connected in a ring array. The conductor 1 is tightly wrapped with the insulation layer 2. The insulation layer 3 is wrapped outside the insulation layer 2. The second shielding layer 4 is wrapped outside the first shielding layer 3. The second shielding layer 5 is wrapped outside the second shielding layer 4.

[0038] Example 2: This example discloses a method for preparing a dielectric modifier, including the following steps:

[0039] Q1: Add 6.25g of polyvinylidene fluoride to a container containing 50mL of N,N-dimethylacetamide, heat and stir at 60℃ and 300rpm to obtain solution 1. Add 0.055g of cuprous chloride, 0.1g of pentamethyldiethylenetriamine and 30g of ethyl methacrylate to solution 1 in sequence. After evacuating and purging with nitrogen, heat to 100℃ and stir at 800rpm for 2h. After the reaction is completed, dilute with tetrahydrofuran, precipitate with methanol, filter, dissolve in N,N-dimethylacetamide, precipitate, wash and dry to obtain monomer 1.

[0040] Q2: Add 0.74g isooctyl acrylate, 0.3g monomer 1 and 1.25g polyurethane acrylate to a container, sonicate for 20min, then add 0.058g photoinitiator, continue sonicating for 5min, then add 70mL distilled water and stir for 20min, irradiate for 8min, wash with ethanol, dry, grind to obtain dielectric modulator.

[0041] This embodiment discloses a method for preparing a composite shielding agent, including the following steps:

[0042] S1: 11.1 g of 4-nitrobenzaldehyde and 12.5 mL of acetic acid were added to 300 mL of propionic acid. The mixture was heated and stirred at 140 °C, and then 4.9 mL of pyrrole was slowly added. The mixture was heated and refluxed at 155 °C for 30 min. After the reaction was completed, the mixture was vacuum filtered and washed with distilled water and methanol until neutral to obtain a solid. Then, 4.6 g of the solid was mixed with 36 mL of pyrrole and heated and refluxed at 120 °C for 1 h. The mixture was then refrigerated for 12 h, washed with acetone, and dried under vacuum to obtain intermediate A. 2.1 g of intermediate A was added to 155 mL of hydrochloric acid. After purging with nitrogen, 8.6 g of stannous chloride was added. The mixture was stirred at room temperature for 2.5 h, heated and refluxed at 80 °C for 30 min, cooled, and refrigerated for 12 h. The mixture was then filtered, dissolved, pH adjusted, and purified to obtain intermediate B.

[0043] S2: 0.29 g of intermediate B and 0.163 g of sodium acetate were added to a mixed solution of 45 mL of chlorobenzene and 31 mL of N,N-dimethylformamide. After stirring and mixing, 0.48 g of cobalt acetate was added. The mixture was stirred and refluxed under a nitrogen atmosphere for 48 h. After stirring, ultrapure water was added, filtered, and dried to obtain intermediate C. 1.5 g of carbon nanotubes were added to a mixed solution of 70 mL of concentrated sulfuric acid and 25 mL of concentrated nitric acid. After stirring magnetically for 1 h, the mixture was ultrasonically stirred in an ice bath for 10 min. Then, the mixture was slowly added to distilled water, centrifuged, pH adjusted to 7, rotary evaporated, and freeze-dried to obtain carboxylated carbon nanotubes.

[0044] S3: Add 1.2g of carboxylated carbon nanotubes to 100mL of distilled water and sonicate for 10min to obtain a mixed solution. Add 1.4g of EDC and 0.5g of NHS to the mixed solution in sequence, stir at room temperature, adjust pH=7, then add 9.1g of intermediate C and 0.12g of triethylamine. Heat the mixture under nitrogen protection. After the reaction is complete, centrifuge, wash, and dry to obtain the composite shielding agent.

[0045] This embodiment discloses a method for producing a double-shielded control cable, including the following steps:

[0046] Step 1: The copper rod with an initial diameter of 12mm is drawn at a speed of 20m / min, and then annealed in a nitrogen-protected annealing furnace at a heating rate of 12℃ / min to 450℃. After holding at this temperature for 45min, it is water-cooled, and then the surface is cleaned by sequentially cleaning with 5wt% citric acid solution and deionized water. After drying, the conductor material is obtained.

[0047] Step 2: Add 2g of dielectric modifier and 75g of cross-linked polyethylene to a twin-screw mixer. The twin-screw mixer rotates at 300 rpm and is 160°C. Extrusion is performed at a speed of 20 m / min and a pressure of 20 MPa. The mixture is cooled in three stages: 70°C in the first stage, 45°C in the second stage, and 25°C in the third stage. The mixture is then shaped to obtain the insulating layer material.

[0048] Step 3: Add the composite shielding agent to the epoxy resin-based conductive adhesive, coat it evenly on the surface of the aluminum foil, and then hot-press it with the polyester film through a hot-press laminating machine to obtain the first shielding layer material. Mix tin-plated copper wire with nickel-coated graphene fiber and then weave it to obtain the second shielding layer material.

[0049] Step 4: Tightly wrap the insulation material around the surface of the conductor material, then wrap the first shielding layer material and the second shielding layer material in sequence, and then wrap the polyurethane material. Emboss to obtain a double-shielded control cable.

[0050] Example 3: This example discloses a method for preparing a dielectric modifier, including the following steps:

[0051] Q1: Add 5g of polyvinylidene fluoride to a container containing 40mL of N,N-dimethylacetamide, heat and stir at 60℃ and 300rpm to obtain solution 1. Add 0.04g of cuprous chloride, 0.08g of pentamethyldiethylenetriamine and 28g of ethyl methacrylate to solution 1 in sequence. After evacuating and purging with nitrogen, heat to 100℃ and stir at 800rpm for 2h. After the reaction is completed, dilute with tetrahydrofuran, precipitate with methanol, filter, dissolve in N,N-dimethylacetamide, precipitate, wash and dry to obtain monomer 1.

[0052] Q2: Add 0.63g of isooctyl acrylate, 0.2g of monomer 1 and 1.5g of polyurethane acrylate to a container, sonicate for 20min, then add 0.054g of photoinitiator, continue sonicating for 5min, then add 80mL of distilled water and stir for 20min, irradiate for 8min, wash with ethanol, dry and grind to obtain dielectric modifier.

[0053] This embodiment discloses a method for preparing a composite shielding agent, including the following steps:

[0054] S1: 10g of 4-nitrobenzaldehyde and 15mL of acetic acid were added to 300mL of propionic acid. The mixture was heated and stirred at 140℃, and then 5.6mL of pyrrole was slowly added. The mixture was heated and refluxed at 155℃ for 30min. After the reaction was completed, the mixture was vacuum filtered and washed with distilled water and methanol until neutral to obtain a solid. Then, 4g of the solid was mixed with 40mL of pyrrole and heated and refluxed at 120℃ for 1h. The mixture was then refrigerated for 12h, washed with acetone, and vacuum dried to obtain intermediate A. 1.7g of intermediate A was added to 130mL of hydrochloric acid. After purging with nitrogen, 9.3g of stannous chloride was added. The mixture was stirred at room temperature for 2.5h, heated and refluxed at 80℃ for 30min, cooled, and refrigerated for 12h. The mixture was filtered, dissolved, pH adjusted, and purified to obtain intermediate B.

[0055] S2: 0.24 g of intermediate B and 0.158 g of sodium acetate were added to a mixed solution of 60 mL of chlorobenzene and 25 mL of N,N-dimethylformamide. After stirring and mixing, 0.42 g of cobalt acetate was added. The mixture was stirred and refluxed under a nitrogen atmosphere for 48 h. After stirring, ultrapure water was added, filtered, and dried to obtain intermediate C. 1 g of carbon nanotubes were added to a mixed solution of 60 mL of concentrated sulfuric acid and 30 mL of concentrated nitric acid. After stirring magnetically for 1 h, the mixture was ultrasonically stirred in an ice bath for 10 min. Then, the mixture was slowly added to distilled water, centrifuged, pH adjusted to 7, rotary evaporated, and freeze-dried to obtain carboxylated carbon nanotubes.

[0056] S3: Add 1.4g of carboxylated carbon nanotubes to 100mL of distilled water and sonicate for 10min to obtain a mixed solution. Add 1.6g of EDC and 0.4g of NHS to the mixed solution in sequence, stir at room temperature, adjust pH=7, then add 10.2g of intermediate C and 0.1g of triethylamine. Heat the mixture under nitrogen protection. After the reaction is complete, centrifuge, wash, and dry to obtain the composite shielding agent.

[0057] This embodiment discloses a method for producing a double-shielded control cable, including the following steps:

[0058] Step 1: The copper rod with an initial diameter of 12mm is drawn at a speed of 20m / min, and then annealed in a nitrogen-protected annealing furnace at a heating rate of 12℃ / min to 450℃. After holding at this temperature for 45min, it is water-cooled, and then the surface is cleaned by sequentially cleaning with 5wt% citric acid solution and deionized water. After drying, the conductor material is obtained.

[0059] Step 2: Add 1g of dielectric modifier and 80g of cross-linked polyethylene to a twin-screw mixer. The twin-screw mixer rotates at 300 rpm and is 160℃. Extrusion is performed at a speed of 20m / min and a pressure of 20MPa. The mixture is cooled in three stages: 70℃ in the first stage, 45℃ in the second stage, and 25℃ in the third stage. The mixture is then shaped to obtain the insulating layer material.

[0060] Step 3: Add the composite shielding agent to the epoxy resin-based conductive adhesive, coat it evenly on the surface of the aluminum foil, and then hot-press it with the polyester film through a hot-press laminating machine to obtain the first shielding layer material. Mix tin-plated copper wire with nickel-coated graphene fiber and then weave it to obtain the second shielding layer material.

[0061] Step 4: Tightly wrap the insulation material around the surface of the conductor material, then wrap the first shielding layer material and the second shielding layer material in sequence, and then wrap the polyurethane material. Emboss to obtain a double-shielded control cable.

[0062] Example 4: This example discloses a method for preparing a dielectric modifier, including the following steps:

[0063] Q1: 7.5g of polyvinylidene fluoride was added to a container containing 60mL of N,N-dimethylacetamide. The mixture was heated and stirred at 60℃ and 300rpm to obtain solution 1. 0.07g of cuprous chloride, 0.13g of pentamethyldiethylenetriamine and 33g of ethyl methacrylate were added to solution 1 in sequence. After evacuating and purging with nitrogen, the mixture was heated to 100℃ and stirred at 800rpm for 2h. After the reaction was completed, the mixture was diluted with tetrahydrofuran, precipitated with methanol, filtered, dissolved in N,N-dimethylacetamide, precipitated, washed and dried to obtain monomer 1.

[0064] Q2: Add 0.85g of isooctyl acrylate, 0.4g of monomer 1 and 1g of polyurethane acrylate to a container, sonicate for 20min, then add 0.06g of photoinitiator, continue sonicating for 5min, then add 60mL of distilled water and stir for 20min, irradiate for 8min, wash with ethanol, dry, grind to obtain dielectric modifier.

[0065] This embodiment discloses a method for preparing a composite shielding agent, including the following steps:

[0066] S1: 12.2 g of 4-nitrobenzaldehyde and 10 mL of acetic acid were added to 300 mL of propionic acid. The mixture was heated and stirred at 140 °C, and then 4.5 mL of pyrrole was slowly added. The mixture was heated and refluxed at 155 °C for 30 min. After the reaction was completed, the mixture was vacuum filtered and washed with distilled water and methanol until neutral to obtain a solid. Then, 5.3 g of the solid was mixed with 32 mL of pyrrole and heated and refluxed at 120 °C for 1 h. The mixture was then refrigerated for 12 h, washed with acetone, and dried under vacuum to obtain intermediate A. 2.5 g of intermediate A was added to 180 mL of hydrochloric acid. After purging with nitrogen, 8 g of stannous chloride was added. The mixture was stirred at room temperature for 2.5 h, heated and refluxed at 80 °C for 30 min, cooled, and refrigerated for 12 h. The mixture was then filtered, dissolved, pH adjusted, and purified to obtain intermediate B.

[0067] S2: 0.35 g of intermediate B and 0.167 g of sodium acetate were added to a mixed solution of 30 mL of chlorobenzene and 36 mL of N,N-dimethylformamide. After stirring and mixing, 0.57 g of cobalt acetate was added. The mixture was stirred and refluxed under a nitrogen atmosphere for 48 h. After stirring, ultrapure water was added, filtered, and dried to obtain intermediate C. 2 g of carbon nanotubes were added to a mixed solution of 80 mL of concentrated sulfuric acid and 20 mL of concentrated nitric acid. After stirring magnetically for 1 h, the mixture was ultrasonically stirred in an ice bath for 10 min. Then, the mixture was slowly added to distilled water, centrifuged, pH adjusted to 7, rotary evaporated, and freeze-dried to obtain carboxylated carbon nanotubes.

[0068] S3: Add 1g of carboxylated carbon nanotubes to 100mL of distilled water and sonicate for 10min to obtain a mixed solution. Add 1.2g of EDC and 0.6g of NHS to the mixed solution in sequence, stir at room temperature, adjust the pH to 7, then add 8g of intermediate C and 0.14g of triethylamine. Under nitrogen protection, heat the reaction. After the reaction is completed, centrifuge, wash, and dry to obtain the composite shielding agent.

[0069] This embodiment discloses a method for producing a double-shielded control cable, including the following steps:

[0070] Step 1: The copper rod with an initial diameter of 12mm is drawn at a speed of 20m / min, and then annealed in a nitrogen-protected annealing furnace at a heating rate of 12℃ / min to 450℃. After holding at this temperature for 45min, it is water-cooled, and then the surface is cleaned by sequentially cleaning with 5wt% citric acid solution and deionized water. After drying, the conductor material is obtained.

[0071] Step 2: Add 3g of dielectric modifier and 70g of cross-linked polyethylene to a twin-screw mixer. The twin-screw mixer rotates at 300 rpm and is 160°C. Extrusion is performed at a speed of 20 m / min and a pressure of 20 MPa. The mixture is cooled in three stages: 70°C in the first stage, 45°C in the second stage, and 25°C in the third stage. The mixture is then shaped to obtain the insulating layer material.

[0072] Step 3: Add the composite shielding agent to the epoxy resin-based conductive adhesive, coat it evenly on the surface of the aluminum foil, and then hot-press it with the polyester film through a hot-press laminating machine to obtain the first shielding layer material. Mix tin-plated copper wire with nickel-coated graphene fiber and then weave it to obtain the second shielding layer material.

[0073] Step 4: Tightly wrap the insulation material around the surface of the conductor material, then wrap the first shielding layer material and the second shielding layer material in sequence, and then wrap the polyurethane material. Emboss to obtain a double-shielded control cable.

[0074] Example 5: This example discloses a method for preparing a dielectric modifier, including the following steps:

[0075] Q1: Add 5.5g of polyvinylidene fluoride to a container containing 45mL of N,N-dimethylacetamide, heat and stir at 60℃ and 300rpm to obtain solution 1. Add 0.05g of cuprous chloride, 0.09g of pentamethyldiethylenetriamine and 29g of ethyl methacrylate to solution 1 in sequence. After evacuating and purging with nitrogen, heat to 100℃ and stir at 800rpm for 2h. After the reaction is completed, dilute with tetrahydrofuran, precipitate with methanol, filter, dissolve in N,N-dimethylacetamide, precipitate, wash and dry to obtain monomer 1.

[0076] Q2: Add 0.68g of isooctyl acrylate, 0.25g of monomer 1 and 1.1g of polyurethane acrylate to a container, sonicate for 20min, then add 0.057g of photoinitiator, continue sonicating for 5min, then add 65mL of distilled water and stir for 20min, irradiate for 8min, wash with ethanol, dry, grind to obtain dielectric modulator.

[0077] This embodiment discloses a method for preparing a composite shielding agent, including the following steps:

[0078] S1: 10.5 g of 4-nitrobenzaldehyde and 11 mL of acetic acid were added to 300 mL of propionic acid. The mixture was heated and stirred at 140 °C, and then 4.7 mL of pyrrole was slowly added. The mixture was heated and refluxed at 155 °C for 30 min. After the reaction was completed, the mixture was vacuum filtered and washed with distilled water and methanol until neutral to obtain a solid. Then, 4.3 g of the solid was mixed with 34 mL of pyrrole and heated and refluxed at 120 °C for 1 h. The mixture was then refrigerated for 12 h, washed with acetone, and dried under vacuum to obtain intermediate A. 2.3 g of intermediate A was added to 140 mL of hydrochloric acid. After purging with nitrogen, 8.3 g of stannous chloride was added. The mixture was stirred at room temperature for 2.5 h, heated and refluxed at 80 °C for 30 min, cooled, and refrigerated for 12 h. The mixture was then filtered, dissolved, pH adjusted, and purified to obtain intermediate B.

[0079] S2: 0.27 g of intermediate B and 0.160 g of sodium acetate were added to a mixed solution of 40 mL of chlorobenzene and 28 mL of N,N-dimethylformamide. After stirring and mixing, 0.46 g of cobalt acetate was added. The mixture was stirred and refluxed under a nitrogen atmosphere for 48 h. After stirring, ultrapure water was added, filtered, and dried to obtain intermediate C. 1.2 g of carbon nanotubes were added to a mixed solution of 65 mL of concentrated sulfuric acid and 22 mL of concentrated nitric acid. After stirring magnetically for 1 h, the mixture was ultrasonically stirred in an ice bath for 10 min. Then, the mixture was slowly added to distilled water, centrifuged, pH adjusted to 7, rotary evaporated, and freeze-dried to obtain carboxylated carbon nanotubes.

[0080] S3: Add 1.1g of carboxylated carbon nanotubes to 100mL of distilled water and sonicate for 10min to obtain a mixed solution. Add 1.3g of EDC and 0.45g of NHS to the mixed solution in sequence, stir at room temperature, adjust pH=7, then add 8.5g of intermediate C and 0.11g of triethylamine. Heat the mixture under nitrogen protection. After the reaction is complete, centrifuge, wash, and dry to obtain the composite shielding agent.

[0081] This embodiment discloses a method for producing a double-shielded control cable, including the following steps:

[0082] Step 1: The copper rod with an initial diameter of 12mm is drawn at a speed of 20m / min, and then annealed in a nitrogen-protected annealing furnace at a heating rate of 12℃ / min to 450℃. After holding at this temperature for 45min, it is water-cooled, and then the surface is cleaned by sequentially cleaning with 5wt% citric acid solution and deionized water. After drying, the conductor material is obtained.

[0083] Step 2: Add 1.5g of dielectric modifier and 72g of cross-linked polyethylene to a twin-screw mixer. The twin-screw mixer rotates at 300 rpm and is 160℃. Extrusion is performed at a speed of 20m / min and a pressure of 20MPa. The mixture is cooled in three stages: 70℃ in the first stage, 45℃ in the second stage, and 25℃ in the third stage. The mixture is then shaped to obtain the insulating layer material.

[0084] Step 3: Add the composite shielding agent to the epoxy resin-based conductive adhesive, coat it evenly on the surface of the aluminum foil, and then hot-press it with the polyester film through a hot-press laminating machine to obtain the first shielding layer material. Mix tin-plated copper wire with nickel-coated graphene fiber and then weave it to obtain the second shielding layer material.

[0085] Step 4: Tightly wrap the insulation material around the surface of the conductor material, then wrap the first shielding layer material and the second shielding layer material in sequence, and then wrap the polyurethane material. Emboss to obtain a double-shielded control cable.

[0086] Comparative Example 1: Compared with Example 1, Comparative Example 1 did not add dielectric regulators during the preparation of the double-shielded control cable, and all other conditions remained unchanged.

[0087] Comparative Example 2: Compared with Example 1, Comparative Example 2 did not add composite shielding agent during the preparation of the double-shielded control cable, and all other conditions remained unchanged.

[0088] Experimental Example: The performance of the double-shielded control cables prepared in Examples 2-5 and Comparative Examples 1-2 was tested. The dielectric properties of the samples were tested according to GB / T 31838.8-2024, the shielding performance according to GB / T 14864-2013, the mechanical properties according to GB / T 7424.2-2008, and the temperature resistance according to GB / T2951.14-2008. The test results are shown in Table 1.

[0089] Table 1

[0090] project Relative permittivity Shielding effectiveness Tensile strength / MPa Elongation at break / % Tensile strength change rate at 80℃ / % Example 2 7.4 78dB 67.5 213.7 11.5 Example 3 7.2 76dB 65.8 212.9 11.8 Example 4 7.2 75dB 66.3 213.1 12.5 Example 5 7.1 74dB 67.1 211.6 12.6 Comparative Example 1 3.5 74dB 42.8 176.9 21.8 Comparative Example 2 7 56dB 42.5 177.4 22.3

[0091] As shown in Table 1, the cables prepared in Examples 2-5 of this invention exhibit excellent dielectric constant, shielding performance, mechanical properties, and thermal stability. A comparison between Comparative Example 1 and Examples 2-5 shows that adding a dielectric modifier can effectively improve the dielectric constant, mechanical properties, and thermal stability of the cable. A comparison between Comparative Example 2 and Examples 2-5 shows that adding a composite shielding agent can effectively improve the shielding performance, mechanical properties, and thermal stability of the cable.

[0092] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0093] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for producing a double-shielded control cable, characterized in that, Includes the following steps: Step 1: The copper rod is drawn into wire, then annealed, and then the surface is cleaned and dried to obtain the conductor material; Step 2: Add dielectric modifier 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 to the epoxy resin-based conductive adhesive, coat it evenly on the surface of the aluminum foil, and then hot-press it with the polyester film through a hot-press laminating machine to obtain the first shielding layer material. Mix tin-plated copper wire with nickel-coated graphene fiber and then weave it to obtain the second shielding layer material. Step 4: Tightly wrap the insulating layer material around the surface of the conductor material, then wrap the first shielding layer material and the second shielding layer material in sequence, and then wrap the polyurethane material. Emboss to obtain a double-shielded control cable. The method for preparing the dielectric modulator includes the following steps: Q1: Polyvinylidene fluoride was added to a container containing N,N-dimethylacetamide, and heated and stirred to obtain solution 1. Cuprous chloride, pentamethyldiethylenetriamine and ethyl methacrylate were added to solution 1 in sequence. After evacuating and purging with nitrogen, the mixture was heated and stirred to react. After the reaction was completed, the mixture was diluted, precipitated, filtered, dissolved, precipitated, washed and dried to obtain monomer 1. Q2: Add isooctyl acrylate, monomer 1 and polyurethane acrylate to a container, mix ultrasonically, then add photoinitiator, continue ultrasonic stirring, then add distilled water and stir, irradiate, wash, dry, grind to obtain dielectric modifier. The preparation method of the composite shielding agent includes the following steps: S1: 4-Nitrobenzaldehyde and acetic acid were added to propionic acid, heated and stirred, and then pyrrole was slowly added. The mixture was heated to reflux and reacted. After the reaction was completed, the mixture was vacuum filtered, washed, and a solid was obtained. The solid was then mixed with pyrrole, heated to reflux, refrigerated, washed, and vacuum dried to obtain intermediate A. Intermediate A was added to hydrochloric acid, nitrogen gas was introduced, and then stannous chloride was added. The mixture was stirred at room temperature, heated to reflux with stirring, cooled, refrigerated, filtered, dissolved, pH adjusted, and purified 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 the 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 sonicate in an ice bath, then slowly add to distilled water, centrifuge, adjust pH, rotary evaporate, and freeze dry to obtain carboxylated carbon nanotubes; S3: Carboxylated carbon nanotubes were added to distilled water and sonicated to obtain a mixed solution. EDC and NHS were added to the mixed solution in sequence, and the solution was stirred at room temperature to adjust the pH. Then, intermediate C and triethylamine were added, and the reaction was carried out under nitrogen protection. After the reaction was completed, the solution was centrifuged, washed, and dried to obtain the composite shielding agent.

2. The method for producing the double-shielded control cable according to claim 1, characterized in that, In step one, the initial diameter of the copper rod is 8-12mm, the wire drawing speed is 20-50m / min, and during the annealing process, the temperature is raised to 420-480℃ in a nitrogen-protected annealing furnace at a heating rate of 10-15℃ / min, held for 30-60min and then water-cooled. The surface is then cleaned sequentially with 5wt% citric acid solution and deionized water.

3. The method for producing the double-shielded control cable according to claim 1, characterized in that, In step two, the ratio of dielectric modifier to cross-linked polyethylene is (1-3)g:(70-80)g. The rotation speed of the twin-screw mixer is 200-400rpm, the temperature is 150-180℃, the extrusion pressure is 15-25MPa, the extrusion speed is 10-30m / min, and the cooling is done in three stages: the first stage is 60-80℃, the second stage is 40-50℃, and the third stage is 20-25℃.

4. The method for producing the double-shielded control cable according to claim 1, characterized in that, In Q1, the 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 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.

5. The method for producing the double-shielded control cable according to claim 1, characterized in that, In S1, the ratio of 4-nitrobenzaldehyde, acetic acid and pyrrole is (10-12.2) g: (10-15) mL: (4.5-5.6) mL, and the ratio of solid to pyrrole is (4-5.3) g: (32-40) mL; the ratio of intermediate A, hydrochloric acid and stannous chloride is (1.7-2.5) g: (130-180) mL: (8-9.3) g.

6. The method for producing the double-shielded control cable according to claim 1, characterized in that, In S2, the 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 ratio of carbon nanotubes, concentrated sulfuric acid and concentrated nitric acid is (1-2) g : (60-80) mL : (20-30) mL.

7. The method for producing the double-shielded control cable according to claim 1, characterized in that, In S3, the 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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