High-voltage strong-pulse-current flexible coaxial cable

Abstract

The invention discloses a high-voltage strong-pulse-current flexible coaxial cable, belongs to the technical field of cable preparation, and is used for solving the technical problem that the flexibility and electromagnetic shielding effectiveness of a coaxial cable in the prior art need to be further improved. The flame-retardant cross-linking agent comprises the single flexible conductor, the insulating layer, the shielding layer and the outer sheath layer are sequentially arranged outside the flexible conductor, the flame-retardant cross-linking agent prepared by the invention improves the flame-retardant wear-resisting property of the flame-retardant material, and the flame-retardant cross-linking agent is used as a carbon source of a modified glue solution to participate in the preparation process of the flexible conductor by utilizing the excellent carbonization property of the flame-retardant cross-linking agent; the graphene flexible conductor outer modification layer is obtained and cooperates with the phlogopite tape, so that the electromagnetic shielding effectiveness and flexibility of the material are remarkably enhanced, and finally, the wear-resistant, flame-retardant and anti-electromagnetic interference flexible coaxial cable is prepared through cooperation of a plurality of hierarchical structures.

Description

Technical Field

[0001] The invention relates to the technical field of cable preparation, in particular to a high-voltage and strong-pulse-current flexible coaxial cable. Background Art

[0002] The design of flexible coaxial cables has undergone major changes in history, from the initial hard materials and simple structures to the current use of highly flexible polymers and complex multi-layer electromagnetic shielding technology. This progress has significantly improved the cable's flexibility, durability and anti-electromagnetic interference capabilities, enabling it to adapt to a variety of usage environments and demanding application requirements;

[0003] However, faced with the challenges of high-frequency transmission and ultra-long distances, cables still need to be improved. Future development may focus on using nanotechnology to optimize shielding materials and develop new synthetic materials to further enhance the performance and reliability of cables. Continuous technological innovation will ensure that flexible coaxial cables continue to play a key role in high-end electronic systems and support the cutting-edge development of communication technology.

[0004] Prior art CN105845221B discloses a flexible mineral insulated cable, comprising a core, a composite filling layer wrapping the core, a fire-resistant layer wrapped outside the composite filling layer, and an outer sheath extruded outside the fire-resistant layer. The core comprises a conductor, an insulating layer extruded outside the conductor, and a wrapping layer wrapped outside the insulating layer. The wrapping layer is composed of a polyimide tape, a shielding coating coated on the outside of the polyimide tape, and a single-sided phlogopite tape wrapped outside the shielding coating. The composite filling layer is composed of a cable PP filling rope and mica powder, the fire-resistant layer is a single-sided phlogopite tape, and the outer sheath is ethylene-vinyl acetate copolymer. The flexible mineral insulated cable of the invention has excellent electrical insulation performance, high temperature resistance, low temperature resistance, excellent fire resistance, environmental protection, and anti-interference performance, and has a high cost performance. In particular, the cable adopts a special coating shielding method, has excellent electromagnetic interference, lightning resistance, balanced potential, and improved power supply quality characteristics, and has excellent bending performance.

[0005] However, the above patent content is to obtain a shielding coating by mixing water-based polyacrylate, shielding filler and auxiliary materials, and combining it with single-sided phlogopite to improve the electromagnetic shielding performance of the material. However, the texture of single-sided phlogopite is relatively brittle, resulting in the flexibility of the material to be further improved. In addition, the shielding filler component inside the shielding coating is single, and the polarity difference with the water-based polyacrylate is large, which can easily lead to weak interfacial bonding of the material. The electromagnetic shielding effectiveness of the material needs to be further improved.

[0006] In view of the technical defects in this aspect, a solution is now proposed. Summary of the invention

[0007] The object of the present invention is to provide a high-voltage and strong pulse current flexible coaxial cable, so as to solve the technical problem in the prior art that the flexibility and electromagnetic shielding effectiveness of the coaxial cable need to be further improved.

[0008] The object of the present invention can be achieved by the following technical scheme: A high voltage and strong pulse current flexible coaxial cable comprises a flexible conductor, and an insulating layer, a shielding layer and an outer sheath layer are sequentially arranged on the outside of the flexible conductor;

[0009] The insulating layer is obtained by extruding a composite polyvinyl chloride material and coating it on the surface of the flexible conductor;

[0010] The shielding layer is obtained by coating the insulating layer with phlogopite tape;

[0011] The outer sheath layer is obtained by extruding a composite polyacrylonitrile material and coating it on the surface of the shielding layer.

[0012] Furthermore, the method for preparing the flexible conductor comprises the following steps:

[0013] A1. Soak the copper wire in the modified glue solution for 3-5 minutes, slowly extract the copper wire, and then use an ultraviolet lamp to cure it for 3-5 minutes. After repeating 3-5 times, use an ultraviolet lamp to cure it for 8-12 hours to obtain a modified copper wire.

[0014] A2, transferring the modified copper wire to a microwave plasma reaction chamber, microwave sintering, forming a carbonized layer with a thickness of 40-50 μm on the outside of the copper wire, and obtaining a carbon-modified copper wire;

[0015] A3. Transfer the carbon-modified copper wire to a hot isostatic pressing furnace, introduce nitrogen, control the pressure of the hot isostatic pressing furnace to 80-100 MPa, and heat it to 500-600°C at a heating rate of 100-120°C / h. Perform isothermal and isobaric reaction for 1-2 hours, cool it naturally to room temperature, and release the pressure to obtain a carbon-modified conductor. Twisting 6-8 carbon-modified conductors obtains a flexible conductor.

[0016] The principle of preparing flexible conductors is as follows: high temperature provides energy to rearrange the carbon atoms in the carbon-modified layer and repair surface defects, thereby forming a more complete and regular graphene lattice; high pressure causes the graphene sheets to be arranged more closely, increasing the interlayer force, thereby improving the overall crystallinity of the material and giving the material better performance; and while optimizing the structure of the carbon-modified layer, the thermal conductivity of the graphene structure is used to anneal the copper wire material to form smaller and more uniform grains inside the copper wire, making the material softer and eliminating the residual stress generated inside the copper wire during processing, ultimately preparing a flexible conductor.

[0017] Furthermore, in step A1, the power of the UV lamp is 600-800 mW / cm 2, wavelength is 360-400nm; in step A2, the power of the microwave plasma reaction chamber is 1800-2000W, the atmosphere is nitrogen, the flow rate is 50-80sccm, the time is 25-30min, and the sintering temperature is 600-650℃.

[0018] Furthermore, the composite polyacrylonitrile material comprises the following raw materials in parts by weight: 80-100 parts of flame retardant, 10-20 parts of filler, 20-30 parts of plasticizer, 2-5 parts of stabilizer, 0.5-2 parts of lubricant, 0.5-1 parts of antioxidant and 0.5-1 parts of ultraviolet stabilizer.

[0019] Furthermore, the filler is one or more of calcium carbonate, white carbon black and talc; the plasticizer is one or more of dioctyl phthalate, diisononyl phthalate and tributyl citrate; the stabilizer is one or two of butylated hydroxytoluene and triphenyl phosphite; the lubricant is one or more of calcium stearate, oxidized polyethylene wax and montan wax; the antioxidant is one or more of tri-tert-butyl hydroxyphenyl acrylate, tetramethyl dihydroxyphenyl acrylate and tri-tert-butyl hydroxyphenyl acrylate; the UV inhibitor is one or more of 2-hydroxy-4-octyloxybenzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazine and 2-hydroxy-4-methoxybenzophenone.

[0020] Furthermore, the preparation method of the modified glue solution comprises the following steps:

[0021] B1. Mix lithium nitrate, titanium nitrate, tin nitrate and deionized water to obtain a paste material, transfer the paste material to a crucible, transfer the crucible to a tube furnace, and calcine to obtain a shielding material;

[0022] B2. Add flame retardant and N,N-dimethylformamide into the reactor, stir for 15-20 minutes at room temperature, then add shielding material into the reactor, continue stirring for 5-8 minutes to obtain modified adhesive solution.

[0023] Furthermore, in step B1, the stirring rate of the reactor is 80-120rpm, the amount ratio of lithium nitrate, titanium nitrate, tin nitrate and deionized water is 8-10g:3-4g:4-5g:60-80mL, and the post-treatment operation is: after nitrogen protection is introduced into the tubular furnace, the temperature is increased to 100-120°C at a heating rate of 3-5°C / min, and after keeping warm for 1-2h, the temperature is continued to be increased to 1000-1200°C at a heating rate of 3-5°C / min, and the mixed powder is obtained after being kept warm and calcined for 10-12h. After washing the mixed powder with anhydrous ethanol and deionized water for 3-5 times, it is transferred to a drying oven at a temperature of 60-80°C and vacuum dried to constant weight to obtain a shielding material; in step B2, the amount ratio of flame retardant, N,N-dimethylformamide and shielding material is 10-12g:80-90mL:2-3g.

[0024] Furthermore, the method for preparing the flame retardant material comprises the following steps:

[0025] C1, adding acrylonitrile, 1-diphenylmethyl-4-(3-phenyl-2-propenyl)piperazine, di(ethylene glycol) ethyl ether methacrylate and N,N-dimethylformamide into a reaction kettle, stirring at room temperature for 8-10 minutes to obtain a prepolymer solution;

[0026] C2. Add the prepolymer liquid into the reactor and stir. After the temperature of the reactor is raised to 60-80°C, add azobisisobutyronitrile into the reactor, keep the temperature for reaction for 1-2 hours, add a flame retardant crosslinking agent into the reactor, keep the temperature for reaction for 20-30 minutes, and post-treat to obtain the flame retardant material.

[0027] The reaction equation for preparing flame retardant is:

[0028]

[0029] Where:

[0030] The reaction principle for preparing flame retardant material is as follows: under the conditions of free radical initiator and heating, the double bonds of acrylonitrile, 1-diphenylmethyl-4-(3-phenyl-2-propenyl)piperazine and di(ethylene glycol) ethyl ether methacrylate are broken to generate free radicals, which are then prepolymerized to form a long chain structure. Finally, a flame retardant crosslinking agent is added to crosslink the long chain structure to form a complex three-dimensional structure to obtain the flame retardant material.

[0031] Furthermore, in step C1, the amount ratio of polyacrylonitrile, 1-diphenylmethyl-4-(3-phenyl-2-propenyl)piperazine and di(ethylene glycol) ethyl ether methacrylate and N,N-dimethylformamide is 8-10g:4-5g:4-5g:60-80mL, and the stirring rate of the reactor is 60-80rpm; in step C2, the amount ratio of the prepolymer liquid, azobisisobutyronitrile and the flame retardant crosslinking agent is 80-100mL:0.8-1.2g:5-6g, and the stirring rate of the reactor is 80-120rpm. The post-treatment is as follows: after the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is transferred to a rotary evaporator at a temperature of 80-90°C, and the solvent is evaporated under reduced pressure to obtain a flame retardant.

[0032] Furthermore, the preparation method of the flame retardant crosslinking agent is: 1-oxiranylmethyl-3,5-di-2-propenyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, triethylamine and N,N-dimethylformamide are added to a reactor, and after the temperature of the reactor is increased to 60-80°C, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is added to the reactor, the reaction is kept warm for 2-4 hours, and the flame retardant crosslinking agent is obtained by post-treatment.

[0033] The reaction equation for preparing the flame retardant crosslinking agent is:

[0034]

[0035] Where:

[0036] The reaction principle for preparing the flame retardant crosslinking agent is as follows: under the catalysis of triethylamine and heating conditions, the epoxy group of 1-oxiranylmethyl-3,5-di-2-propenyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione undergoes ring opening to form a free radical, which reacts with the phosphorus-hydrogen bond on 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to finally prepare the flame retardant crosslinking agent. The mass spectrometry analysis data of the flame retardant crosslinking agent are: m / z: 439.09 (100.0%), 440.10 (23.1%), 441.10 (3.8%), 440.09 (1.1%).

[0037] Furthermore, the dosage ratio of 1-oxiranylmethyl-3,5-di-2-propenyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, triethylamine, N,N-dimethylformamide and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 8-10g:0.5-0.8g:40-50mL:6-8g, and the post-treatment is as follows: after the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction solution is transferred to a rotary evaporator at a temperature of 80-90°C, and the solvent is evaporated under reduced pressure to obtain an flame retardant.

[0038] The operation of extruding and coating the composite polyvinyl chloride material on the surface of the flexible conductor to obtain an insulating layer is as follows: adding the composite polyvinyl chloride material to a twin-screw extruder, the temperatures of the eight temperature sections of the twin-screw extruder from the feed port toward the discharge port are 160°C, 165, 165°C, 170°C, 170°C, 180°C, 180°C, and 190°C respectively, the main engine speed of the twin-screw extruder is 80-120rpm, the pressure is 100-150bar, and after melt extrusion, it is coated on the outside of the flexible conductor to obtain an insulating layer.

[0039] Further, the composite polyvinyl chloride material comprises the following raw materials in parts by weight: 80-100 parts of polyvinyl chloride, 10-20 parts of filler, 20-30 parts of plasticizer, 2-5 parts of stabilizer and 0.5-2 parts of lubricant;

[0040] Furthermore, the filler is one or more of calcium carbonate, white carbon black and talc; the plasticizer is one or more of dioctyl phthalate, diisononyl phthalate and tributyl citrate; the stabilizer is one or two of butylated hydroxytoluene and triphenyl phosphite; the lubricant is one or more of calcium stearate, oxidized polyethylene wax and montan wax.

[0041] The operation of coating the insulating layer with phlogopite tape to obtain the shielding layer is as follows: transfer the phlogopite tape to the surface of the insulating layer, use a vacuum roller press to roll, set the temperature of the vacuum roller press to 80-100℃, the pressure to 0.3-0.5MPa, and the speed to 5-8mm / s. After rolling, transfer the material to a UV curing machine and set the UV intensity to 80-100mW / cm 2 , the curing time is 5-8min, and a shielding layer is obtained.

[0042] The operation of extruding and coating the composite polyacrylonitrile material on the surface of the shielding layer to obtain the outer sheath layer is as follows: adding the composite polyacrylonitrile material to a twin-screw extruder, the temperatures of the eight temperature sections of the twin-screw extruder from the feed port toward the discharge port are 190°C, 215, 215°C, 230°C, 230°C, 235°C, 235°C, and 240°C, respectively, the main engine speed of the twin-screw extruder is 80-120rpm, and the pressure is 100-150bar, and after melt extrusion, it is coated on the outside of the shielding layer to obtain the outer sheath layer.

[0043] The present invention has the following beneficial effects:

[0044] 1. The present invention improves the flame retardant and wear-resistant properties of flame retardant materials by preparing flame retardant cross-linking agents. When the flame retardant materials are at high temperatures, they decompose to produce acidic substances, and the nitrile groups on the chain segments cooperate with the piperazine structures to promote the carbonization of the materials. The excellent carbonization properties of the flame retardant materials are used as the carbon source of the modified adhesive to participate in the preparation process of the flexible conductor, thereby obtaining the outer modified layer of the graphene-based flexible conductor, which cooperates with the phlogopite tape to significantly enhance the electromagnetic shielding efficiency and flexibility of the material. Finally, through the coordinated cooperation of multiple hierarchical structures, a wear-resistant, flame-retardant and electromagnetic interference-resistant flexible coaxial cable is prepared.

[0045] 2. In the process of preparing the flexible conductor, the present invention provides energy to rearrange the carbon atoms of the carbon modification layer by high temperature in a hot isostatic pressing furnace, repairs surface defects, and thus forms a more complete and regular graphene lattice. The high pressure causes the graphene sheets to be arranged more closely, increases the interlayer force, thereby improving the overall crystallinity of the material and giving the material better performance. While optimizing the structure of the carbon modification layer, the thermal conductivity of the graphene structure is used to anneal the copper wire material, so that smaller and more uniform grains are formed inside the copper wire, making the material softer, and eliminating the residual stress generated inside the copper wire during the processing, ultimately significantly enhancing the flexibility of the flexible coaxial cable.

[0046] 3. In the process of preparing flexible conductors, the present invention uses a shielding material obtained by calcining a metal inorganic salt as a part of the modified glue to participate in the preparation process of the flexible conductor. The carbon modified layer on the surface of the flexible conductor and the phlogopite tape cooperate with each other, and finally improve the electromagnetic shielding effectiveness of the cable. The flame retardant material prepared after cross-linking with a flame retardant cross-linking agent has a more complex spatial segment structure, thereby improving the wear resistance of the outer skin layer, and structural decomposition occurs during the combustion process. The acidic substance and the nitrile group coordinate to promote the carbonization of the material and release a large amount of flame retardant gas, which finally significantly improves the flame retardant and wear resistance of the material. DETAILED DESCRIPTION

[0047] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Example 1

[0049] This embodiment provides a method for preparing a flame retardant material for preparing a high voltage and high pulse current flexible coaxial cable, comprising the following steps:

[0050] Step ①: Preparation of flame retardant crosslinking agent

[0051] Weigh: 800.0g1-oxiranylmethyl-3,5-di-2-propenyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 50.0gtriethylamine and 4.0LN,N-dimethylformamide are added into a reactor. After the temperature of the reactor is raised to 60°C, 600.0g9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is added into the reactor. The reaction is kept warm for 2h. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction solution is transferred to a rotary evaporator at a temperature of 80°C, and the solvent is evaporated under reduced pressure to obtain an flame retardant.

[0052] Step ②: Preparation of prepolymer solution

[0053] Weigh 800.0 g of acrylonitrile, 400.0 g of 1-benzhydryl-4-(3-phenyl-2-propenyl)piperazine, 400.0 g of di(ethylene glycol)ethyl ether methacrylate and 6.0 L of N,N-dimethylformamide, add them into a reaction kettle, stir at room temperature for 8 min at a stirring rate of 60 rpm to obtain a prepolymer solution.

[0054] Step 3: Preparation of flame retardant

[0055] Weigh: 8.0L prepolymer liquid is added to the reactor and stirred at a stirring rate of 80rpm. After the temperature of the reactor is raised to 60°C, 80.0g of azobisisobutyronitrile is added to the reactor. After the reaction is kept warm for 1h, 500.0g of flame retardant cross-linking agent is added to the reactor and the reaction is kept warm for 20min. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is transferred to a rotary evaporator at a temperature of 80°C, and the solvent is evaporated under reduced pressure to obtain a flame retardant material.

[0056] Example 2

[0057] This embodiment provides a method for preparing a flame retardant material for preparing a high voltage and high pulse current flexible coaxial cable, comprising the following steps:

[0058] Step ①: Preparation of flame retardant crosslinking agent

[0059] Weigh: 1000.0g 1-oxiranylmethyl-3,5-di-2-propenyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 80.0g triethylamine and 5.0L N,N-dimethylformamide and add them into a reactor. After the temperature of the reactor is increased to 80°C, 800.0g 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is added to the reactor. The reaction is kept warm for 4h. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction solution is transferred to a rotary evaporator at a temperature of 90°C, and the solvent is evaporated under reduced pressure to obtain an flame retardant.

[0060] Step ②: Preparation of prepolymer solution

[0061] Weigh: 1000.0 g acrylonitrile, 500.0 g 1-benzhydryl-4-(3-phenyl-2-propenyl)piperazine, 500.0 g di(ethylene glycol)ethyl ether methacrylate and 8.0 L N,N-dimethylformamide, add into a reaction kettle, stir at room temperature for 10 min at a stirring rate of 80 rpm to obtain a prepolymer solution.

[0062] Step 3: Preparation of flame retardant

[0063] Weigh: 10.0L prepolymer liquid is added to the reactor and stirred at a stirring rate of 120rpm. After the temperature of the reactor is raised to 80°C, 120.0g of azobisisobutyronitrile is added to the reactor. After the reaction is kept warm for 2h, 600.0g of flame retardant cross-linking agent is added to the reactor and the reaction is kept warm for 30min. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is transferred to a rotary evaporator at a temperature of 90°C, and the solvent is evaporated under reduced pressure to obtain a flame retardant material.

[0064] Example 3

[0065] This embodiment provides a method for preparing a flame retardant material for preparing a high voltage and high pulse current flexible coaxial cable, comprising the following steps:

[0066] Step ①: Preparation of flame retardant crosslinking agent

[0067] Weigh: 900.0g1-oxiranylmethyl-3,5-di-2-propenyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 65.0gtriethylamine and 4.5LN,N-dimethylformamide are added into a reactor. After the temperature of the reactor is raised to 70°C, 700.0g9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is added into the reactor. The reaction is kept warm for 3h. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction solution is transferred to a rotary evaporator at a temperature of 85°C, and the solvent is evaporated under reduced pressure to obtain an flame retardant.

[0068] Step ②: Preparation of prepolymer solution

[0069] Weigh 900.0 g of acrylonitrile, 450.0 g of 1-benzhydryl-4-(3-phenyl-2-propenyl)piperazine, 450.0 g of di(ethylene glycol)ethyl ether methacrylate and 7.0 L of N,N-dimethylformamide, add them into a reaction kettle, stir at room temperature for 9 minutes at a stirring rate of 70 rpm to obtain a prepolymer solution.

[0070] Step 3: Preparation of flame retardant

[0071] Weigh: 9.0L prepolymer liquid is added to the reactor and stirred at a stirring rate of 100rpm. After the temperature of the reactor is raised to 70°C, 100.0g of azobisisobutyronitrile is added to the reactor. After the reaction is kept warm for 2h, 550.0g of flame retardant crosslinking agent is added to the reactor and the reaction is kept warm for 25min. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is transferred to a rotary evaporator at a temperature of 85°C, and the solvent is evaporated under reduced pressure to obtain a flame retardant material.

[0072] Example 4

[0073] This embodiment provides a method for preparing a modified adhesive solution for preparing a high-voltage and high-pulse current flexible coaxial cable, comprising the following steps:

[0074] Step ⑴: Prepare shielding material

[0075] Weigh: 800.0g lithium nitrate, 300.0g titanium nitrate, 400.0g tin nitrate and 6.0L deionized water, mix and stir to obtain a paste material, the stirring rate is 80rpm, transfer the paste material into a crucible, transfer the crucible to a tubular furnace, and then introduce nitrogen into the tubular furnace, heat it to 100°C at a heating rate of 3°C / min, keep it warm for 1h, and then continue to heat it to 1000°C at a heating rate of 3°C / min. After keeping warm for 10h, obtain a mixed powder. Wash the mixed powder 3 times with anhydrous ethanol and deionized water, transfer it to a drying oven at 60°C and vacuum dry it to constant weight to obtain a shielding material.

[0076] Step (2): preparing shielding material

[0077] Weigh: 1000.0 g of the flame retardant prepared in Example 1 and 8.0 L of N,N-dimethylformamide are added to a reactor, stirred at room temperature for 15 min, then 200.0 g of shielding material is added to the reactor, and stirring is continued for 5 min to obtain a modified adhesive solution.

[0078] Example 5

[0079] This embodiment provides a method for preparing a modified adhesive solution for preparing a high-voltage and high-pulse current flexible coaxial cable, comprising the following steps:

[0080] Step ⑴: Prepare shielding material

[0081] Weigh: 1000.0g lithium nitrate, 400.0g titanium nitrate, 500.0g tin nitrate and 8.0L deionized water, mix and stir to obtain a paste material, the stirring rate is 120rpm, transfer the paste material into a crucible, transfer the crucible to a tubular furnace, and then introduce nitrogen into the tubular furnace, heat it to 120°C at a heating rate of 5°C / min, keep it warm for 2h, and then continue to heat it to 1200°C at a heating rate of 5°C / min. After keeping warm for 12h, obtain a mixed powder. Wash the mixed powder 5 times with anhydrous ethanol and deionized water, transfer it to a drying oven at 80°C and vacuum dry it to constant weight to obtain a shielding material.

[0082] Step (2): preparing shielding material

[0083] Weigh: 1200.0 g of the flame retardant prepared in Example 2 and 9.0 L of N,N-dimethylformamide are added to a reactor, stirred at room temperature for 20 min, then 300.0 g of shielding material is added to the reactor, and stirring is continued for 8 min to obtain a modified adhesive solution.

[0084] Example 6

[0085] This embodiment provides a method for preparing a modified adhesive solution for preparing a high-voltage and high-pulse current flexible coaxial cable, comprising the following steps:

[0086] Step ⑴: Prepare shielding material

[0087] Weigh: 900.0g lithium nitrate, 350.0g titanium nitrate, 450.0g tin nitrate and 7.0L deionized water, mix and stir to obtain a paste material, the stirring rate is 100rpm, transfer the paste material into a crucible, transfer the crucible to a tubular furnace, and then introduce nitrogen into the tubular furnace, heat it to 100°C at a heating rate of 4°C / min, keep it warm for 2h, and then continue to heat it to 1200°C at a heating rate of 4°C / min. After keeping warm for 11h, a mixed powder is obtained. After washing the mixed powder 4 times with anhydrous ethanol and deionized water, transfer it to a drying oven at a temperature of 70°C and vacuum dry it to constant weight to obtain a shielding material.

[0088] Step (2): preparing shielding material

[0089] Weigh: 1100.0 g of the flame retardant prepared in Example 3 and 8.5 L of N,N-dimethylformamide were added to a reactor, stirred at room temperature for 18 min, and then 250.0 g of shielding material was added to the reactor, and stirring was continued for 7 min to obtain a modified adhesive solution.

[0090] Example 7

[0091] This embodiment provides a method for preparing a flexible conductor for preparing a high voltage and high pulse current flexible coaxial cable, comprising the following steps:

[0092] Step Ⅰ: Preparation of modified copper wire

[0093] The copper wire was immersed in the modified glue prepared in Example 4 for 3 minutes, and after the copper wire was slowly extracted, it was irradiated and cured with an ultraviolet lamp for 3 minutes. The power of the ultraviolet lamp was 600 mW / cm 2 , with a wavelength of 360nm, repeated 3 times, and then cured with an ultraviolet lamp for 8h to obtain a modified copper wire.

[0094] Step II: Preparation of carbon-modified copper wire

[0095] The modified copper wire was transferred to a microwave plasma reaction chamber with a power of 1800 W, a nitrogen atmosphere, a flow rate of 50 sccm, and a time of 25 min. Microwave sintering was performed to obtain a carbon-modified copper wire with a carbon layer thickness of 40 μm.

[0096] Step III: Preparation of flexible conductor

[0097] The carbon-modified copper wire was transferred to a hot isostatic pressing furnace, nitrogen was introduced, the pressure of the hot isostatic pressing furnace was controlled at 80 MPa, and the temperature was increased to 500°C at a heating rate of 100°C / h. The isothermal and isobaric reaction was carried out for 1 hour, and the wire was naturally cooled to room temperature. The pressure was released to obtain a flexible conductor.

[0098] Example 8

[0099] This embodiment provides a method for preparing a flexible conductor for preparing a high voltage and high pulse current flexible coaxial cable, comprising the following steps:

[0100] Step Ⅰ: Preparation of modified copper wire

[0101] The copper wire was immersed in the modified glue prepared in Example 5 for 5 minutes, and after the copper wire was slowly extracted, it was irradiated and cured with an ultraviolet lamp for 5 minutes. The power of the ultraviolet lamp was 800 mW / cm 2 , with a wavelength of 400nm, repeated 5 times, and then cured with an ultraviolet lamp for 12h to obtain a modified copper wire.

[0102] Step II: Preparation of carbon-modified copper wire

[0103] The modified copper wire was transferred to a microwave plasma reaction chamber with a power of 2000 W, a nitrogen atmosphere, a flow rate of 80 sccm, and a time of 30 min. Microwave sintering was performed to obtain a carbon-modified copper wire with a carbon layer thickness of 50 μm.

[0104] Step III: Preparation of flexible conductor

[0105] The carbon-modified copper wire was transferred to a hot isostatic pressing furnace, nitrogen was introduced, the pressure of the hot isostatic pressing furnace was controlled at 100 MPa, and the temperature was increased to 6000°C at a heating rate of 120°C / h. The isothermal and isobaric reaction was carried out for 2 hours, and the furnace was naturally cooled to room temperature. The pressure was released to obtain a flexible conductor.

[0106] Example 9

[0107] This embodiment provides a method for preparing a flexible conductor for preparing a high voltage and high pulse current flexible coaxial cable, comprising the following steps:

[0108] Step Ⅰ: Preparation of modified copper wire

[0109] The copper wire was immersed in the modified glue prepared in Example 6 for 4 minutes, and after the copper wire was slowly extracted, it was cured by ultraviolet light for 4 minutes. The power of the ultraviolet light was 700 mW / cm 2 , with a wavelength of 380nm, repeated 4 times, and then cured with an ultraviolet lamp for 10 hours to obtain a modified copper wire.

[0110] Step II: Preparation of carbon-modified copper wire

[0111] The modified copper wire was transferred to a microwave plasma reaction chamber with a power of 1900 W, a nitrogen atmosphere, a flow rate of 65 sccm, and a time of 28 min. Microwave sintering was performed to obtain a carbon-modified copper wire with a carbon layer thickness of 45 μm.

[0112] Step III: Preparation of flexible conductor

[0113] The carbon-modified copper wire was transferred to a hot isostatic pressing furnace, nitrogen was introduced, the pressure of the hot isostatic pressing furnace was controlled at 90 MPa, and the temperature was increased to 550°C at a heating rate of 110°C / h. The isothermal and isobaric reaction was carried out for 2 hours, and the furnace was naturally cooled to room temperature. The pressure was released to obtain a flexible conductor.

[0114] Example 10

[0115] This embodiment provides a method for preparing a high-voltage and high-pulse current flexible coaxial cable, comprising the following steps:

[0116] Step 1: Prepare the insulation layer

[0117] Weigh: 8.0 kg of polyvinyl chloride, 1.0 kg of calcium carbonate, 2.0 kg of dioctyl phthalate, 200.0 g of triphenyl phosphite and 50.0 g of calcium stearate and add them to a twin-screw extruder. The temperatures of the eight temperature sections of the twin-screw extruder from the feed port toward the discharge port are 160° C., 165, 165° C., 170° C., 170° C., 180° C., 180° C., and 190° C., respectively. The main engine speed of the twin-screw extruder is 80 pm, and the pressure is 100 bar. After melt extrusion, it is coated on the outside of the flexible conductor prepared in Example 7 to obtain an insulating layer.

[0118] Step 2: Prepare the shielding layer

[0119] Transfer the phlogopite tape to the surface of the insulation layer and roll it with a vacuum roller press. Set the temperature of the vacuum roller press to 80°C, the pressure to 0.3MPa, and the speed to 5mm / s. After rolling, transfer the material to a UV curing machine and set the UV intensity to 80mW / cm 2 , the curing time is 5 minutes, and a shielding layer is obtained.

[0120] Step 3: Prepare flexible coaxial cable

[0121] Weigh: 8.0 kg of the flame retardant prepared in Example 3, 2.0 kg of calcium carbonate, 3.0 kg of diisononyl phthalate, 500.0 g of triphenyl phosphite, 200.0 g of calcium stearate, 100.0 g of tri-tert-butyl hydroxyphenyl acrylate and 100.0 g of 2-hydroxy-4-octyloxybenzophenone and add them to a twin-screw extruder. The temperatures of the eight temperature sections of the twin-screw extruder from the feed port toward the discharge port are 190° C., 215, 215° C., 230° C., 230° C., 235° C., 235° C., 240° C., the main engine speed of the twin-screw extruder is 80 rpm, and the pressure is 100 bar. After melt extrusion, it is coated on the outside of the shielding layer to obtain an outer sheath layer, that is, a flexible coaxial cable is obtained.

[0122] Embodiment 11

[0123] This embodiment provides a method for preparing a high-voltage and high-pulse current flexible coaxial cable, comprising the following steps:

[0124] Step 1: Prepare the insulation layer

[0125] Weigh: 10.0 kg of polyvinyl chloride, 2.0 kg of calcium carbonate, 3.0 kg of dioctyl phthalate, 500.0 g of triphenyl phosphite and 200.0 g of calcium stearate are added to a twin-screw extruder, the temperatures of the eight temperature sections of the twin-screw extruder from the feed port toward the discharge port are 160° C., 165, 165° C., 170° C., 170° C., 180° C., 180° C., 190° C., the main engine speed of the twin-screw extruder is 120 rpm, the pressure is 150 bar, and after melt extrusion, it is coated on the outside of the flexible conductor prepared in Example 8 to obtain an insulating layer.

[0126] Step 2: Prepare the shielding layer

[0127] Transfer the phlogopite tape to the surface of the insulation layer and roll it with a vacuum roller press. Set the temperature of the vacuum roller press to 100°C, the pressure to 0.5MPa, and the speed to 8mm / s. After rolling, transfer the material to a UV curing machine and set the UV intensity to 100mW / cm2 , the curing time is 8 minutes, and a shielding layer is obtained.

[0128] Step 3: Prepare flexible coaxial cable

[0129] Weigh: 10.0 kg of the flame retardant prepared in Example 2, 2.0 kg of calcium carbonate, 3.0 kg of diisononyl phthalate, 500.0 g of triphenyl phosphite, 200.0 g of calcium stearate, 100.0 g of tri-tert-butyl hydroxyphenyl acrylate and 100.0 g of 2-hydroxy-4-octyloxybenzophenone are added to a twin-screw extruder, and the temperatures of the eight temperature sections of the twin-screw extruder from the feed port toward the discharge port are 190° C., 215, 215° C., 230° C., 230° C., 235° C., 235° C., 240° C., the main engine speed of the twin-screw extruder is 120 rpm, and the pressure is 150 bar. After melt extrusion, it is coated on the outside of the shielding layer to obtain an outer sheath layer, that is, a flexible coaxial cable is obtained.

[0130] Example 12

[0131] This embodiment provides a method for preparing a high-voltage and high-pulse current flexible coaxial cable, comprising the following steps:

[0132] Step 1: Prepare the insulation layer

[0133] Weigh: 9.0 kg of polyvinyl chloride, 1.5 kg of calcium carbonate, 2.5 kg of dioctyl phthalate, 350.0 g of triphenyl phosphite and 150.0 g of calcium stearate and add them to a twin-screw extruder. The temperatures of the eight temperature sections of the twin-screw extruder from the feed port toward the discharge port are 160° C., 165, 165° C., 170° C., 170° C., 180° C., 180° C., and 190° C., respectively. The main engine speed of the twin-screw extruder is 100 rpm, and the pressure is 125 bar. After melt extrusion, it is coated on the outside of the flexible conductor prepared in Example 9 to obtain an insulating layer.

[0134] Step 2: Prepare the shielding layer

[0135] Transfer the phlogopite tape to the surface of the insulation layer and roll it with a vacuum roller press. Set the temperature of the vacuum roller press to 90°C, the pressure to 0.4MPa, and the speed to 6mm / s. After rolling, transfer the material to a UV curing machine and set the UV intensity to 90mW / cm 2 , the curing time is 6 minutes, and a shielding layer is obtained.

[0136] Step 3: Prepare flexible coaxial cable

[0137] Weigh: 9.0 kg of the flame retardant prepared in Example 3, 1.5 kg of calcium carbonate, 2.5 kg of diisononyl phthalate, 350.0 g of triphenyl phosphite, 150.0 g of calcium stearate, 80.0 g of tri-tert-butyl hydroxyphenyl acrylate and 75.0 g of 2-hydroxy-4-octyloxybenzophenone and add them to a twin-screw extruder, the temperatures of the eight temperature sections of the twin-screw extruder from the feed port toward the discharge port are 190° C., 215, 215° C., 230° C., 230° C., 235° C., 235° C., 240° C., the main engine speed of the twin-screw extruder is 100 rpm, and the pressure is 125 bar. After melt extrusion, it is coated on the outside of the shielding layer to obtain an outer sheath layer, that is, a flexible coaxial cable is obtained.

[0138] Comparative Example 1

[0139] The difference between this comparative example and Example 12 is that, during the preparation of the flexible conductor used in step 1, step III is omitted.

[0140] Comparative Example 2

[0141] The difference between this comparative example and Example 12 is that when preparing the flexible conductor used in step 1, shielding material is not added to the modified adhesive used.

[0142] Comparative Example 3

[0143] The difference between this comparative example and Example 12 is that when preparing the flexible conductor used in step 1, an equal amount of polyacrylonitrile is used in the modified adhesive to replace the flame retardant.

[0144] Comparative Example 4

[0145] The difference between this comparative example and Example 12 is that in step 3, an equal amount of polyvinyl chloride is used to replace the flame retardant.

[0146] Performance Test:

[0147] The wear resistance of the flexible coaxial cables prepared in Examples 10-12 and Comparative Examples 1-4 was tested with reference to GB / T 3960-2016 "Test Methods for Sliding Friction and Wear of Plastics";

[0148] The anti-electromagnetic interference level of the flexible coaxial cables prepared in Examples 10-12 and Comparative Examples 1-4 was tested with reference to the standard GB / T 19666-2019 "General Technical Requirements for Electromagnetic Shielding Films";

[0149] Referring to the standard GB / T 17737.314-2018 "Coaxial communication cable Part 1-314: Mechanical test method cable bending test", the flexible coaxial cables prepared in Examples 10-12 and Comparative Examples 1-4 were subjected to a cyclic bending test, the number of cycles was recorded, and the flexibility of the flexible coaxial cables was measured;

[0150] The flame retardant grades of the flexible coaxial cables prepared in Examples 10-12 and Comparative Examples 1-4 were tested with reference to the standard GB / T 35575-2017 “General Rules for Flame Retardant and Fire Resistant Wires, Cables or Optical Cables”. The specific data are shown in Table 1.

[0151] Table 1-Performance data of each sample

[0152]

[0153] Data Analysis:

[0154] Comparative analysis of the data in Table 1 above shows that the wear amount of the flexible coaxial cable prepared by the present invention is 6.14 mg, the anti-electromagnetic interference level is SE-1, the number of cyclic torsion is 3.43 million times, and the vertical burning level is V-0, all of which are better than the comparative example;

[0155] By comparing the data of Example 12 and Comparative Example 1, it can be found that the high temperature in the hot isostatic pressing furnace provides energy for rearranging the carbon atoms of the carbon modified layer, repairing surface defects, thereby forming a more complete and regular graphene lattice, and the high pressure causes the graphene sheets to be arranged more closely, increasing the interlayer force, thereby improving the overall crystallinity of the material and giving the material better performance; and while optimizing the structure of the carbon modified layer, the thermal conductivity of the graphene structure is used to anneal the copper wire material, so that smaller and more uniform grains are formed inside the copper wire, making the material softer, and eliminating the residual stress generated inside the copper wire during the processing, and finally significantly enhancing the flexibility of the flexible coaxial cable;

[0156] By comparing the data of Example 12 and Comparative Example 2, it can be found that by using the shielding material obtained by calcining metal inorganic salts as a part of the modified glue to participate in the preparation process of the flexible conductor, the carbon modified layer on the surface of the flexible conductor and the phlogopite tape cooperate with each other, ultimately improving the electromagnetic shielding effectiveness of the cable.

[0157] By comparing the data of Example 12 and Comparative Example 3, it can be found that the electromagnetic interference performance and flexibility of the flexible coaxial cable prepared in Example 15 are significantly reduced, indicating that the flame retardant prepared by the present invention will decompose at high temperature to produce acidic substances, and the nitrile group and piperazine structure on the chain segment will cooperate to promote the carbonization of the material. Thus, a more excellent graphene-based flexible conductor outer modification layer is obtained, thereby significantly enhancing the electromagnetic shielding effectiveness and flexibility of the material;

[0158] By comparing the data of Example 12 and Comparative Example 4, it can be found that the flame retardant material prepared in Example 15 forms a more complex spatial segment structure after being cross-linked by the flame retardant cross-linking agent, thereby improving the wear resistance of the outer skin layer, and structural decomposition occurs during the combustion process, and the acidic substance and the nitrile group coordinate to promote the carbonization of the material and release a large amount of flame retardant gas, ultimately significantly improving the flame retardant and wear resistance of the material;

[0159] The present invention improves the flame retardant and wear-resistant properties of flame retardant fuel by preparing a flame retardant cross-linking agent, and utilizes its excellent carbonization performance to use it as a carbon source for modified rubber liquid to participate in the process of preparing flexible conductors. Finally, through the coordinated cooperation of multiple hierarchical structures, a wear-resistant, flame-retardant and electromagnetic interference-resistant flexible coaxial cable is prepared.

[0160] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. High voltage and strong pulse current flexible coaxial cable, characterized in that: It comprises a single flexible conductor, and an insulating layer, a shielding layer and an outer sheath layer are sequentially arranged on the outside of the flexible conductor; The insulating layer is obtained by extruding a composite polyvinyl chloride material and coating it on the surface of the flexible conductor; The shielding layer is obtained by coating the insulating layer with phlogopite tape; The outer sheath layer is obtained by extruding a composite polyacrylonitrile material and coating it on the surface of the shielding layer.

2. The high voltage and strong pulse current flexible coaxial cable according to claim 1, characterized in that: The method for preparing the flexible conductor comprises the following steps: A1. Soak the copper wire in the modified glue solution for 3-5 minutes, slowly extract the copper wire, and then use an ultraviolet lamp to cure it for 3-5 minutes. After repeating 3-5 times, use an ultraviolet lamp to cure it for 8-12 hours to obtain a modified copper wire. A2, transferring the modified copper wire to a microwave plasma reaction chamber, microwave sintering, forming a carbonized layer with a thickness of 40-50 μm on the outside of the copper wire, and obtaining a carbon-modified copper wire; A3. Transfer the carbon-modified copper wire to a hot isostatic pressing furnace, introduce nitrogen, control the pressure of the hot isostatic pressing furnace to 80-100 MPa, and heat it to 500-600°C at a heating rate of 100-120°C / h. Perform isothermal and isobaric reaction for 1-2 hours, cool it naturally to room temperature, and release the pressure to obtain a carbon-modified conductor. Twisting 6-8 carbon-modified conductors obtains a flexible conductor.

3. The high voltage and strong pulse current flexible coaxial cable according to claim 2, characterized in that: In step A1, the power of the ultraviolet lamp is 600-800mW / cm², and the wavelength is 360-400nm; in step A2, the power of the microwave plasma reaction chamber is 1800-2000W, the atmosphere is nitrogen, the flow rate is 50-80sccm, the time is 25-30min, and the sintering temperature is 600-650℃; the composite polyacrylonitrile material includes the following raw materials in parts by weight: 80-100 parts of flame retardant, 10-20 parts of filler, 20-30 parts of plasticizer, 2-5 parts of stabilizer, 0.5-2 parts of lubricant, 0.5-1 parts of antioxidant and 0.5-1 parts of ultraviolet stabilizer.

4. The high voltage and strong pulse current flexible coaxial cable according to claim 2, characterized in that: The preparation method of the modified glue solution comprises the following steps: B1. Mix lithium nitrate, titanium nitrate, tin nitrate and deionized water to obtain a paste material, transfer the paste material to a crucible, transfer the crucible to a tube furnace, and calcine to obtain a shielding material; B2. Add flame retardant and N,N-dimethylformamide into the reactor, stir for 15-20 minutes at room temperature, then add shielding material into the reactor, continue stirring for 5-8 minutes to obtain modified adhesive solution.

5. The high voltage and strong pulse current flexible coaxial cable according to claim 4, characterized in that: In step B1, the stirring rate of the reactor is 80-120rpm, and the amount ratio of lithium nitrate, titanium nitrate, tin nitrate and deionized water is 8-10g:3-4g:4-5g:60-80mL; in step B2, the amount ratio of flame retardant, N,N-dimethylformamide and shielding material is 10-12g:80-90mL:2-3g.

6. The high voltage and strong pulse current flexible coaxial cable according to claim 4, characterized in that: The method for preparing the flame retardant material comprises the following steps: C1, adding acrylonitrile, 1-diphenylmethyl-4-(3-phenyl-2-propenyl)piperazine, di(ethylene glycol) ethyl ether methacrylate and N,N-dimethylformamide into a reaction kettle, stirring at room temperature for 8-10 minutes to obtain a prepolymer solution; C2. Add the prepolymer liquid into the reactor and stir. After the temperature of the reactor is raised to 60-80°C, add azobisisobutyronitrile into the reactor, keep the temperature for reaction for 1-2 hours, add a flame retardant crosslinking agent into the reactor, keep the temperature for reaction for 20-30 minutes, and post-treat to obtain the flame retardant material.

7. The high voltage and strong pulse current flexible coaxial cable according to claim 6, characterized in that: In step C1, the amount ratio of polyacrylonitrile, 1-diphenylmethyl-4-(3-phenyl-2-propenyl)piperazine, di(ethylene glycol)ethyl ether methacrylate and N,N-dimethylformamide is 8-10 g:4-5 g:4-5 g:60-80 mL, and the stirring rate of the reactor is 60-80 rpm; in step C2, the amount ratio of the prepolymer solution, azobisisobutyronitrile and the flame retardant crosslinking agent is 80-100 mL:0.8-1.2 g:5-6 g, and the stirring rate of the reactor is 80-120 rpm.

8. The high voltage and strong pulse current flexible coaxial cable according to claim 6, characterized in that: The preparation method of the flame retardant crosslinking agent comprises the following steps: adding 1-oxiranylmethyl-3,5-di-2-propenyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, triethylamine and N,N-dimethylformamide into a reaction kettle, raising the temperature of the reaction kettle to 60-80° C., adding 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide into the reaction kettle, keeping the temperature for reaction for 2-4 hours, and post-treating to obtain the flame retardant crosslinking agent.

9. The high voltage and strong pulse current flexible coaxial cable according to claim 8, characterized in that: The usage ratio of 1-oxiranylmethyl-3,5-di-2-propenyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, triethylamine, N,N-dimethylformamide and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 8-10g:0.5-0.8g:40-50mL:6-8g.

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