Anti-electromagnetic interference flame-retardant flexible control cable

Abstract

The invention discloses an anti-electromagnetic interference flame-retardant flexible control cable, which belongs to the technical field of communication equipment and is obtained by co-extruding zinc borate nanosheet composite porous vermiculite, a porous carbon / nanosheet compound, polyvinyl chloride, di-iso-decylphthalate, triphenyl phosphate and a calcium-zinc stabilizer serving as cable materials of an insulating layer in the cable. Micron-sized pores are formed between layers of acid-activated modified expanded vermiculite, a reaction monomer zinc nitrate hexahydrate is impregnated between the layers of the vermiculite, then the zinc nitrate hexahydrate serves as a zinc source, sodium tetraborate decahydrate serves as a boron source, a double decomposition reaction is carried out under the hydrothermal condition, and the zinc borate nanosheets are generated. Zinc borate nanosheets are directionally grown between layers and on the surface of vermiculite, and the zinc borate nanosheets are effectively fixed, so that the flame-retardant effect is stably exerted.

Description

Technical Field

[0001] This invention belongs to the field of communication equipment technology, specifically a flame-retardant flexible control cable that resists electromagnetic interference. Background Technology

[0002] Cables include power cables, control cables, compensating cables, shielded cables, high-temperature cables, computer cables, signal cables, coaxial cables, fire-resistant cables, marine cables, mining cables, aluminum alloy cables, and so on. They are all composed of single or multiple strands of conductors and insulation layers, used to connect circuits and electrical appliances. Currently, while commercially available cables offer good power transmission capabilities, they still have shortcomings that need improvement. Their electromagnetic insulation performance is relatively poor, and their flame-retardant properties need further enhancement. This not only affects power transmission efficiency but also poses certain safety hazards, potentially causing fires and resulting in economic losses.

[0003] Chinese Patent No. CN114914022B discloses an anti-electromagnetic and flame-retardant cable. In this scheme, the inorganic porous substrate is uniformly dispersed in an aqueous dispersion of octylphenol polyoxyethylene ether under ultrasonic dispersion. Then, an appropriate amount of nano zinc borate is added and ultrasonically dispersed again to ensure that the nano zinc borate is uniformly dispersed on the surface and in the pores of the inorganic porous substrate. Then, γ-aminopropylmethyldiethoxysilane is used as a modifier. The modifier and diphenyl phosphoryl chloride are added. The modifier can chemically react with the relevant groups in diphenyl phosphoryl chloride and chemically react with the hydroxyl groups on the surface of the inorganic porous substrate. Finally, the modifier can be effectively "grafted" onto the surface and pores of the inner wall of the inorganic porous substrate, realizing the "chemical fixation" of nano zinc borate.

[0004] However, in the above scheme, the silanol bonds obtained by hydrolyzing γ-aminopropylmethyldiethoxysilane can be grafted onto the inorganic porous substrate, while the hydroxyl groups of nano zinc borate will compete with the hydroxyl groups on the surface of the inorganic porous substrate, and cannot effectively fix the nano zinc borate. Due to its high specific surface area and surface energy, nano zinc borate is prone to agglomeration and cannot better cooperate with the inorganic porous substrate to exert a flame retardant effect. Summary of the Invention

[0005] The purpose of this invention is to provide a flame-retardant flexible control cable that resists electromagnetic interference. It utilizes acid-activated modified expanded vermiculite to form micron-sized pores, and impregnates the reactive monomer zinc nitrate hexahydrate between the vermiculite layers to achieve directional growth of zinc borate nanosheets on the surface, effectively fixing the zinc borate nanosheets and thus stably exerting the flame-retardant effect.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A flame-retardant flexible control cable resistant to electromagnetic interference is prepared by the following steps:

[0008] Step 1: Utilize the interlayer formation of micron-sized pores in acid-activated modified expanded vermiculite, impregnate the interlayer of vermiculite with zinc nitrate hexahydrate, and generate zinc borate nanosheets through metathesis reaction to obtain zinc borate nanosheet composite porous vermiculite.

[0009] Step 2: 4-Aminophenylboronic acid is grafted onto chitosan to obtain boric acid-modified chitosan. Boric acid-modified porous nanospheres are then prepared by the sol-gel method. Zinc metal-organic frameworks are then synthesized in situ on the surface to obtain a composite porous precursor.

[0010] Step 3: Ammonia is used as the nitrogen source, and the zinc metal-organic framework on the surface of the composite porous precursor is used as the boron source. The reaction is heated to generate a porous carbon / nanosheet composite.

[0011] Step 4: Polyvinyl chloride, diisodecyl phthalate, triphenyl phosphate, porous carbon / nanoflake composite, zinc borate nanosheet composite porous vermiculite, and calcium zinc stabilizer are placed in a twin-screw extruder for extrusion granulation to obtain flexible control cable material. The flexible control cable material is used as the insulation layer, conductor, and protective layer, and a flame-retardant flexible control cable with electromagnetic interference resistance is obtained by non-crosslinking three-layer co-extrusion.

[0012] Furthermore, the specific steps for the zinc borate nanosheet composite porous vermiculite in step one are as follows:

[0013] Expanded vermiculite powder was acid-washed with a nitric acid solution of concentration 0.6-0.8 mol / L to obtain modified expanded vermiculite powder. The modified expanded vermiculite powder, zinc nitrate hexahydrate, and deionized water were added to a reaction vessel and stirred for 30-40 min at 20-25℃ and 400-500 r / min. Vacuum impregnation was then carried out for 40-60 min. Then, a sodium tetraborate decahydrate solution of mass fraction 40-50% was added, and the mixture was heated to 70-80℃ and reacted for 24-26 h. After natural cooling to room temperature, the mixture was filtered, and the filter cake was washed 2-3 times with deionized water and vacuum dried at 60-80℃ for 1-2 h to obtain zinc borate nanosheet composite porous vermiculite.

[0014] Furthermore, the ratio of modified expanded vermiculite powder, zinc nitrate hexahydrate, deionized water, and sodium tetraborate decahydrate solution is 4-5 kg: 3-4 kg: 15-20 L: 2-3 L.

[0015] Furthermore, the specific steps for the composite porous precursor in step two are as follows:

[0016] Boric acid-modified porous nanospheres, N,N-dimethylformamide, and deionized water were added to a reaction vessel. Then, sodium hexadecyl sulfate, used as a surfactant, was dissolved in a 60-70% ethanol solution and added to the reaction vessel. The mixture was stirred at 120-130℃ and 400-500 r / min for 30-40 min. Zinc sulfate was then added, and the reaction was continued for 3-4 h. The mixture was allowed to cool naturally to room temperature, filtered, and the filter cake was washed 2-3 times with deionized water and dried under vacuum at 60-80℃ for 1-2 h to obtain the composite porous precursor.

[0017] Furthermore, the ratio of boric acid-modified porous nanospheres, N,N-dimethylformamide, deionized water, sodium hexadecyl sulfate, ethanol solution, and zinc sulfate is 2-3 kg: 4-5 L: 2-3 L: 100-120 g: 700-800 mL: 1-2 kg.

[0018] Furthermore, boric acid-modified porous nanospheres were prepared via the following steps:

[0019] Isooctane and Span 85 were added to a reaction vessel and stirred for 30-40 min at 0-4℃ and 400-500 r / min. Then, boric acid-modified chitosan solution was added and stirring was continued for 1-2 h. The mixture was heated to 70-80℃ and stirred for 30-40 min. The mixture was then allowed to cool naturally to room temperature, filtered, and the filter cake was washed 2-3 times with deionized water. The cake was then vacuum dried at 60-80℃ for 1-2 h to obtain boric acid-modified porous nanospheres.

[0020] Furthermore, the ratio of isooctane, Span 85, and boric acid-modified chitosan solution is 50-60 kg: 5-6 kg: 8-9 kg.

[0021] Furthermore, the boric acid-modified chitosan solution was prepared via the following steps:

[0022] Chitosan powder and 1% acetic acid solution were added to a reaction vessel and stirred to dissolve. Then 4-aminophenylboronic acid was added and stirred for 6-7 hours at 20-25℃ and 400-500 r / min. The mixture was filtered, and the filter cake was washed 2-3 times with deionized water and dried under vacuum at 60-80℃ for 1-2 hours to obtain boric acid modified chitosan powder.

[0023] Boric acid-modified chitosan powder, 4-5% lithium hydroxide solution, 6-7% sodium hydroxide solution, and 7-8% urea solution were added to a reaction vessel and stirred for 30-40 minutes at 30-35℃ and 400-500 r / min to obtain a boric acid-modified chitosan solution.

[0024] Furthermore, the ratio of chitosan powder, acetic acid solution, and 4-aminophenylboronic acid is 1-2 kg: 7-8 L: 3-4 kg.

[0025] Furthermore, the ratio of boric acid-modified chitosan powder, lithium hydroxide solution, sodium hydroxide solution, and urea solution is 1-2 kg: 6-7 kg: 6-7 kg: 6-7 kg.

[0026] Furthermore, the specific steps of the porous carbon / nanosheet composite described in step three are as follows:

[0027] The composite porous precursor was transferred to a muffle furnace and heated to 300-400°C under argon protection at a heating rate of 10-12°C / min. The argon gas was then stopped, and ammonia gas was introduced at a heating rate of 20-25°C / min to heat to 900-1000°C. The temperature was maintained for 2-3 hours, and the mixture was allowed to cool naturally. The product was then added to a 1 mol / L hydrochloric acid solution and ultrasonically washed for 4-5 hours. The mixture was then filtered, washed, and vacuum dried to obtain the porous carbon / nanosheet composite.

[0028] Furthermore, in step four, the ratio of polyvinyl chloride, diisodecyl phthalate, triphenyl phosphate, porous carbon / nanosheet composite, zinc borate nanosheet composite porous vermiculite, and calcium-zinc stabilizer is 9-10 kg: 1-2 kg: 800-900 g: 500-600 g: 300-400 g: 40-80 g.

[0029] The beneficial effects of this invention are:

[0030] 1. The electromagnetic interference-resistant flame-retardant flexible control cable prepared by the present invention is obtained by co-extrusion of cable material with zinc borate nanosheets composite porous vermiculite, porous carbon / nanofiber composite, polyvinyl chloride, diisodecyl phthalate, triphenyl phosphate and calcium zinc stabilizer as the insulation layer of the cable. This gives the cable excellent electromagnetic interference resistance and flame retardancy, excellent mechanical properties, high strength and bending resistance.

[0031] 2. The zinc borate nanosheet composite porous vermiculite of the present invention forms micron-sized pores in the interlayer of acid-activated vermiculite. The reactive monomer zinc nitrate hexahydrate is impregnated into the interlayer of vermiculite. Then, using zinc nitrate hexahydrate as the zinc source and sodium tetraborate decahydrate as the boron source, a metathesis reaction occurs under hydrothermal conditions to generate zinc borate nanosheets. This achieves directional growth of zinc borate nanosheets in the interlayer and on the surface of vermiculite, further increasing the specific surface area and roughness. Zinc borate itself has flame-retardant properties. During combustion, the glassy capping layer generated by its decomposition works synergistically with the carbon layer to form a glassy inorganic expansion coating, covering the material surface to isolate oxygen. Simultaneously, the released water vapor and inert gas dilute the concentration of combustible gases, inhibiting flame propagation. The layered structure of the porous vermiculite provides anchoring points for the zinc borate nanosheets, forming a three-dimensional cross-linked network. The expansion of the vermiculite interlayer and the glassy capping layer generated by the decomposition of zinc borate work synergistically to form an inorganic expansion barrier, blocking oxygen and heat transfer.

[0032] 3. The porous carbon / nanosheet composite of the present invention involves an esterification reaction between the borate groups of 4-aminophenylboronic acid and the hydroxyl groups in the chitosan structure, followed by the preparation of boric acid-modified porous nanospheres via a sol-gel method. Using 4-aminophenylboronic acid as a monomer, a zinc metal-organic framework is synthesized in situ. The coordination bonds in the zinc metal-organic framework have high bond energy, exhibit rigidity, and possess porous properties, which can serve as a reinforcing phase to disperse the stress of the boric acid-modified porous nanospheres, further increasing their strength. Furthermore, at high temperatures, ammonia provides the nitrogen source for the zinc metal... Boric acid in the organic framework provides the boron source, forming a porous carbon-supported boron nitride nanosheet structure. The boron nitride atom structure lacks free or unpaired electrons, a characteristic that determines its low sensitivity to magnetic fields. Boron nitride possesses high resistivity and electrical insulation, effectively blocking current conduction and reducing electromagnetic interference. The layered structure of boron nitride, combined with the glassy substance generated from the decomposition of zinc borate, forms a denser heat-insulating layer. The boron oxide glassy substance generated from the pyrolysis of zinc borate can penetrate into the interlayer of the modified expanded vermiculite powder, forming a dense insulating layer that significantly increases flame retardancy. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1: A flame-retardant flexible control cable resistant to electromagnetic interference is prepared through the following steps:

[0035] S1: Expanded vermiculite powder was acid-washed with 0.6 mol / L nitric acid solution to obtain modified expanded vermiculite powder. 4 kg of modified expanded vermiculite powder, 3 kg of zinc nitrate hexahydrate and 15 L of deionized water were added to a reaction vessel and stirred for 30 min at 20 °C and 400 r / min. Vacuum impregnation was performed for 40 min. 2 L of 40% sodium tetraborate decahydrate solution was added, and the mixture was heated to 70 °C and reacted for 24 h. After natural cooling to room temperature, the mixture was filtered, and the filter cake was washed twice with deionized water and vacuum dried at 60 °C for 1 h to obtain zinc borate nanosheet composite porous vermiculite.

[0036] Acid-activated expanded vermiculite forms micron-sized pores in its interlayer, increasing its specific surface area and the number of active sites. By impregnating the reactive monomer zinc nitrate hexahydrate into the interlayer of vermiculite, and then using zinc nitrate hexahydrate as the zinc source and sodium tetraborate decahydrate as the boron source, a metathesis reaction occurs under hydrothermal conditions to generate zinc borate nanosheets. This achieves the directional growth of zinc borate nanosheets in the interlayer and on the surface of vermiculite, further increasing the specific surface area and roughness.

[0037] S2: Add 1 kg of chitosan powder and 7 L of 1% acetic acid solution to a reaction vessel and stir to dissolve. Then add 3 kg of 4-aminophenylboronic acid and stir for 6 h at 20 °C and 400 r / min. Filter the mixture and wash the filter cake twice with deionized water. Dry it under vacuum at 60 °C for 1 h to obtain boric acid modified chitosan powder.

[0038] 3 kg of boric acid-modified chitosan powder, 6 kg of 4% lithium hydroxide solution, 6 kg of 6% sodium hydroxide solution, and 6 kg of 7% urea solution were added to a reactor and stirred at 30°C and 400 rpm for 30 min to obtain a boric acid-modified chitosan solution. 50 kg of isooctane and 5 kg of Span 85 were added to the reactor and stirred at 0°C and 400 rpm for 30 min. Then, 8 kg of the boric acid-modified chitosan solution was added, and stirring was continued for 1 h. The mixture was heated to 70°C and stirred for another 30 min. After natural cooling to room temperature, the mixture was filtered, and the filter cake was washed twice with deionized water and dried under vacuum at 60°C for 1 h to obtain boric acid-modified porous nanospheres.

[0039] The borate group of 4-aminophenylboronic acid undergoes an esterification reaction with the hydroxyl group in the chitosan structure to obtain borate-modified porous nanospheres.

[0040] S3: Add 2 kg of boric acid-modified porous nanospheres, 4 L of N,N-dimethylformamide and 2 L of deionized water to a reaction vessel. Dissolve 100 g of sodium hexadecyl sulfate in 700 mL of 60% ethanol solution and add it to the reaction vessel. Stir at 120 °C and 400 r / min for 30 min. Add 1 kg of zinc sulfate and continue stirring for 3 h. Cool naturally to room temperature, filter, wash the filter cake twice with deionized water, and vacuum dry at 60 °C for 1 h to obtain the composite porous precursor.

[0041] Using 4-aminophenylboronic acid as a monomer, a zinc metal-organic framework structure was synthesized in situ to further enhance the strength of boric acid-modified porous nanospheres.

[0042] S4: The composite porous precursor was transferred to a muffle furnace and heated to 300°C under argon protection at a heating rate of 10°C / min. Argon was then stopped, and ammonia was introduced at a heating rate of 20°C / min to heat to 900°C. The temperature was maintained for 2 hours, and the mixture was allowed to cool naturally to room temperature. The product was then added to a 1 mol / L hydrochloric acid solution and ultrasonically washed for 4 hours. The mixture was filtered, and the filter cake was washed twice with deionized water and vacuum dried at 60°C for 1 hour to obtain the porous carbon / nanosheet composite.

[0043] At high temperatures, ammonia provides the nitrogen source, and boric acid in the zinc metal-organic framework provides the boron source, generating boron nitride nanosheets that attach to the composite porous precursor to obtain a porous carbon / nanosheet composite. The layered structure of boron nitride can combine with the glass generated by the decomposition of zinc borate during combustion to form a denser heat insulation layer.

[0044] S5: 9 kg of polyvinyl chloride, 1 kg of diisodecyl phthalate, 800 g of triphenyl phosphate, 500 g of porous carbon / nanofibers composite, 300 g of zinc borate nanosheet composite porous vermiculite, and 40 g of calcium-zinc stabilizer are placed in a twin-screw extruder and extruded to granulate to obtain flexible control cable material. The flexible control cable material is used as the insulation layer, conductor, and protective layer, and a non-crosslinked three-layer co-extrusion method is used to obtain a flame-retardant flexible control cable with electromagnetic interference resistance.

[0045] Example 2: A flame-retardant flexible control cable resistant to electromagnetic interference is prepared through the following steps:

[0046] S1: Expanded vermiculite powder was acid-washed with 0.7 mol / L nitric acid solution to obtain modified expanded vermiculite powder; 4.5 kg of modified expanded vermiculite powder, 3.5 kg of zinc nitrate hexahydrate and 17.5 L of deionized water were added to a reaction vessel and stirred at 22.5 °C and 450 r / min for 35 min, and vacuum impregnated for 50 min. Then, 2.5 L of sodium tetraborate decahydrate solution with a mass fraction of 45% was added, heated to 75 °C, and reacted for 25 h. After naturally cooling to room temperature, the mixture was filtered, and the filter cake was washed twice with deionized water and vacuum dried at 70 °C for 1.5 h to obtain zinc borate nanosheet composite porous vermiculite.

[0047] S2: 1.2 kg of chitosan powder and 7.8 L of 1% acetic acid solution were added to a reaction vessel and stirred to dissolve. Then, 3.4 kg of 4-aminophenylboronic acid was added and stirred at 23 °C and 450 r / min for 6.7 h. The mixture was filtered, and the filter cake was washed twice with deionized water and dried under vacuum at 70 °C for 1.2 h to obtain boric acid modified chitosan powder.

[0048] 3.4 kg of boric acid-modified chitosan powder, 6.7 kg of lithium hydroxide solution with a mass fraction of 4.5%, 6.7 kg of sodium hydroxide solution with a mass fraction of 6.7%, and 6.7 kg of urea solution with a mass fraction of 7.8% were added to a reaction vessel and stirred for 35 min at 33℃ and 450 r / min to obtain boric acid-modified chitosan solution.

[0049] 55 kg of isooctane and 5.6 kg of Span 85 were added to a reactor and stirred for 35 min at 3 °C and 450 r / min. Then, 8.9 kg of boric acid-modified chitosan solution was added and stirring was continued for 1.2 h. The mixture was heated to 75 °C and stirred for another 35 min. After cooling naturally to room temperature, the mixture was filtered. The filter cake was washed twice with deionized water and dried under vacuum at 70 °C for 1.5 h to obtain boric acid-modified porous nanospheres. S3: 2.5 kg of boric acid-modified porous nanospheres, 4.5 L of N,N-dimethylformamide, and 2.5 L of deionized water were added to a reaction vessel. 110 g of sodium hexadecyl sulfate as a surfactant was dissolved in 750 mL of 65% ethanol solution and added to the reaction vessel. The mixture was stirred at 125 °C and 450 r / min for 35 min. Then, 1.5 kg of zinc sulfate was added, and the reaction was continued to be stirred for 3.5 h. The mixture was allowed to cool naturally to room temperature, filtered, and the filter cake was washed twice with deionized water and dried under vacuum at 70 °C for 1.5 h to obtain the composite porous precursor.

[0050] S4: The composite porous precursor was transferred to a muffle furnace and heated to 350°C under argon protection at a heating rate of 11°C / min. Argon was then stopped, and ammonia was introduced at a heating rate of 23°C / min to heat to 950°C. The temperature was maintained for 2.5 h, and the mixture was allowed to cool naturally to room temperature. The product was then added to a 1 mol / L hydrochloric acid solution and ultrasonically washed for 4.5 h. After filtration, the filter cake was washed twice with deionized water and vacuum dried at 70°C for 1.5 h to obtain the porous carbon / nanosheet composite.

[0051] S5: 9.5 kg of polyvinyl chloride, 1.5 kg of diisodecyl phthalate, 850 g of triphenyl phosphate, 550 g of porous carbon / nanofibers composite, 350 g of zinc borate nanosheet composite porous vermiculite, and 60 g of calcium-zinc stabilizer are placed in a twin-screw extruder and extruded to obtain flexible control cable material. The flexible control cable material is used as the insulation layer, conductor, and protective layer, and a flame-retardant flexible control cable with electromagnetic interference resistance is obtained by non-crosslinking three-layer co-extrusion.

[0052] Example 3: A flame-retardant flexible control cable resistant to electromagnetic interference, prepared through the following steps:

[0053] S1: Expanded vermiculite powder was acid-washed with 0.8 mol / L nitric acid solution to obtain modified expanded vermiculite powder; 5 kg of modified expanded vermiculite powder, 4 kg of zinc nitrate hexahydrate and 20 L of deionized water were added to a reaction vessel and stirred for 40 min at 25 °C and 500 r / min, and then vacuum impregnated for 60 min. Then, 3 L of 50% sodium tetraborate decahydrate solution was added, heated to 80 °C and reacted for 26 h. After naturally cooling to room temperature, the mixture was filtered, and the filter cake was washed three times with deionized water and vacuum dried at 80 °C for 2 h to obtain zinc borate nanosheet composite porous vermiculite.

[0054] S2: Add 1 kg of chitosan powder and 7 L of 1% acetic acid solution to a reaction vessel and stir to dissolve. Then add 3 kg of 4-aminophenylboronic acid and stir for 7 h at 25 °C and 500 r / min. Filter the mixture and wash the filter cake three times with deionized water. Dry the mixture under vacuum at 80 °C for 2 h to obtain boric acid modified chitosan powder.

[0055] 2 kg of boric acid-modified chitosan, 7 kg of 5% lithium hydroxide solution, 7 kg of 7% sodium hydroxide solution and 7 kg of 8% urea solution were added to a reaction vessel and stirred for 40 min at 35℃ and 500 r / min to obtain boric acid-modified chitosan solution.

[0056] 60 kg of isooctane and 6 kg of Span 85 were added to a reactor and stirred for 40 min at 4 °C and 500 r / min. Then, 9 kg of boric acid-modified chitosan solution was added and stirred for another 2 h. The mixture was then heated to 80 °C and stirred for another 40 min. After cooling naturally to room temperature, the mixture was filtered. The filter cake was washed three times with deionized water and dried under vacuum at 80 °C for 2 h to obtain boric acid-modified porous nanospheres.

[0057] S3: Add 3 kg of boric acid-modified porous nanospheres, 5 L of N,N-dimethylformamide, and 3 L of deionized water to a reaction vessel. Dissolve 120 g of sodium hexadecyl sulfate as a surfactant in 800 mL of 70% ethanol solution and add it to the reaction vessel. Stir at 130 °C and 500 r / min for 40 min. Then add 2 kg of zinc sulfate and continue stirring for 4 h. Cool naturally to room temperature, filter, wash the filter cake three times with deionized water, and vacuum dry at 80 °C for 2 h to obtain the composite porous precursor.

[0058] S4: The composite porous precursor was transferred to a muffle furnace and heated to 400°C under argon protection at a heating rate of 12°C / min. Argon was then stopped, and ammonia was introduced at a heating rate of 25°C / min to heat to 1000°C. The temperature was maintained for 3 hours, and the mixture was allowed to cool naturally to room temperature. The product was then added to a 1 mol / L hydrochloric acid solution and ultrasonically washed for 5 hours. The mixture was filtered, and the filter cake was washed three times with deionized water and vacuum dried at 80°C for 2 hours to obtain the porous carbon / nanosheet composite.

[0059] S5: 10 kg of polyvinyl chloride, 2 kg of diisodecyl phthalate, 900 g of triphenyl phosphate, 600 g of porous carbon / nanofibers composite, 400 g of zinc borate nanosheet composite porous vermiculite, and 80 g of calcium-zinc stabilizer are placed in a twin-screw extruder and extruded to granulate to obtain flexible control cable material. The flexible control cable material is used as the insulation layer, conductor, and protective layer, and a non-crosslinked three-layer co-extrusion method is used to obtain a flame-retardant flexible control cable with electromagnetic interference resistance.

[0060] Comparative Example 1: Referring to the inorganic porous substrate product described in paragraph 15 of the Chinese Patent Specification with Publication No. CN114914022B, based on Example 3 of the present invention, the modified expanded vermiculite powder in step S2 was replaced with the inorganic porous substrate product to obtain zinc borate nanosheet composite porous vermiculite, and the remaining steps remained unchanged, to prepare a flame-retardant flexible control cable with electromagnetic interference resistance.

[0061] Comparative Example 2: Based on Example 3, without step S2, modified expanded vermiculite powder and nano zinc borate were directly mixed and stirred, with the remaining steps unchanged, to prepare a flame-retardant flexible control cable resistant to electromagnetic interference.

[0062] Comparative Example 3: Based on Example 3, 4-aminophenylboronic acid in step S3 was replaced with 2-aminobenzoic acid, while the other steps remained unchanged, to prepare a flame-retardant flexible control cable resistant to electromagnetic interference.

[0063] Performance tests were conducted on the flame-retardant flexible control cables with electromagnetic interference resistance obtained in Examples 1-3 and Comparative Examples 1-3.

[0064] In the examples and comparative examples:

[0065] Sodium tetraborate decahydrate was purchased from Hubei Langbowan Biomedical Co., Ltd.

[0066] 4-Aminophenylboronic acid was purchased from Sigma-Aldrich (Shanghai) Co., Ltd. Polyvinyl chloride was purchased from Shanghai Yingxin Laboratory Equipment Co., Ltd.

[0067] 1. Tensile strength and elongation at break: The tensile strength and elongation at break were tested in accordance with GB / T 2951.11-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Cables - Part 11: General Test Methods for Thickness and Dimensional Measurement and Mechanical Properties".

[0068] 2. Limiting oxygen index test: The limiting oxygen index was tested in accordance with GB / T 2406.2-2009 "Determination of flammability of plastics by oxygen index method - Part 2: Room temperature test".

[0069] 3. Shielding effectiveness: The test was conducted in accordance with GB / T 12190-2021 "Test Method for Shielding Effectiveness of Electromagnetic Shielding Rooms", and the results are shown in Table 1:

[0070] Table 1. Performance Test Results of Flame-Retardant Flexible Control Cables with Electromagnetic Interference Resistance

[0071]

[0072] As can be seen from Table 1, the flame-retardant flexible control cables with electromagnetic interference resistance prepared in Examples 1-3 have significantly better breaking elongation, tensile strength, limiting oxygen index and shielding effectiveness than the comparative examples. This indicates that the flame-retardant flexible control cables with electromagnetic interference resistance prepared by the present invention have excellent electromagnetic resistance, flame retardancy and moisture resistance, excellent mechanical properties, high strength and bending resistance.

[0073] In Comparative Example 1, the modified expanded vermiculite powder was replaced with an inorganic porous substrate product. Through acid activation, micron-sized pores were formed between the expanded vermiculite layers, increasing the specific surface area and the number of active sites, which enabled better growth of nano-zinc borate. Furthermore, the expanded vermiculite itself can expand at high temperatures, effectively synergistically enhancing the flame-retardant effect of nano-zinc borate.

[0074] In Comparative Example 2, modified expanded vermiculite powder and nano-zinc borate were directly stirred and mixed. The reactive monomer zinc nitrate hexahydrate was impregnated in the interlayer spacing of expanded vermiculite. The large specific surface area of ​​expanded vermiculite facilitated the fixation of zinc nitrate hexahydrate, thereby achieving the directional growth of zinc borate nanosheets in the interlayer and on the surface of vermiculite, further increasing the specific surface area and roughness.

[0075] In Comparative Example 3, 4-aminophenylboronic acid was replaced with 2-aminobenzoic acid. At high temperature, ammonia provided the nitrogen source, and boric acid in the zinc metal-organic framework provided the boron source, generating boron nitride nanosheets that adhered to the composite porous precursor, resulting in a porous carbon / nanosheet composite. When 4-aminophenylboronic acid was replaced with 2-aminobenzoic acid, the generated zinc metal-organic framework did not contain boron ions, and therefore boron nitride nanosheet structures could not be generated.

[0076] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A flame-retardant flexible control cable resistant to electromagnetic interference, characterized in that, Prepared by the following steps: Step 1: Utilize the interlayer formation of micron-sized pores in acid-activated modified expanded vermiculite, impregnate the interlayer of vermiculite with zinc nitrate hexahydrate, and generate zinc borate nanosheets through metathesis reaction to obtain zinc borate nanosheet composite porous vermiculite; Step 2: 4-Aminophenylboronic acid is grafted onto chitosan to obtain boric acid-modified chitosan. Boric acid-modified porous nanospheres are then prepared by the sol-gel method. Zinc metal-organic frameworks are then synthesized in situ on the surface to obtain a composite porous precursor. Step 3: Ammonia is used as the nitrogen source, and the zinc metal-organic framework on the surface of the composite porous precursor is used as the boron source. The reaction is heated to generate a porous carbon / nanosheet composite. Step 4: Polyvinyl chloride, diisodecyl phthalate, triphenyl phosphate, porous carbon / nanoflake composite, zinc borate nanosheet composite porous vermiculite, and calcium zinc stabilizer are placed in a twin-screw extruder for extrusion granulation to obtain flexible control cable material. The flexible control cable material is used as the insulation layer, conductor, and protective layer, and a flame-retardant flexible control cable with electromagnetic interference resistance is obtained by non-crosslinking three-layer co-extrusion.

2. The flame-retardant flexible control cable with electromagnetic interference resistance according to claim 1, characterized in that, The specific steps for the zinc borate nanosheet composite porous vermiculite described in step one are as follows: Expanded vermiculite powder was acid-washed with 0.6-0.8 mol / L nitric acid solution to obtain modified expanded vermiculite powder. The modified expanded vermiculite powder, zinc nitrate hexahydrate and deionized water were added to a reaction vessel and stirred at 20-25℃ and 400-500 r / min for 30-40 min. Vacuum impregnation was performed for 40-60 min, and then 40-50 wt% sodium tetraborate decahydrate solution was added. The mixture was heated to 70-80℃ and the reaction was continued for 24-26 h. After natural cooling to room temperature, the mixture was filtered, washed, and vacuum dried to obtain zinc borate nanosheet composite porous vermiculite.

3. The flame-retardant flexible control cable with electromagnetic interference resistance according to claim 2, characterized in that, The ratio of the modified expanded vermiculite powder, zinc nitrate hexahydrate, deionized water, and sodium tetraborate decahydrate solution is 4-5 kg: 3-4 kg: 15-20 L: 2-3 L.

4. The flame-retardant flexible control cable with electromagnetic interference resistance according to claim 1, characterized in that, The specific steps for the composite porous precursor described in step two are as follows: Boric acid-modified porous nanospheres, N,N-dimethylformamide, and deionized water were added to a reaction vessel. Then, sodium hexadecyl sulfate was dissolved in 60-70 wt% ethanol solution and added to the reaction vessel. The mixture was stirred at 120-130℃ and 400-500 r / min for 30-40 min. Zinc sulfate was then added, and the reaction was continued with stirring for 3-4 h. After natural cooling, the mixture was filtered, washed, and vacuum dried to obtain the composite porous precursor.

5. The flame-retardant flexible control cable with electromagnetic interference resistance according to claim 4, characterized in that, The ratio of boric acid-modified porous nanospheres, N,N-dimethylformamide, deionized water, sodium hexadecyl sulfate, ethanol solution, and zinc sulfate is 2-3 kg: 4-5 L: 2-3 L: 100-120 g: 700-800 mL: 1-2 kg.

6. The flame-retardant flexible control cable with electromagnetic interference resistance according to claim 4, characterized in that, The boric acid-modified porous nanospheres were prepared through the following steps: Isooctane and Span 85 were added to a reaction vessel and stirred at 0-4℃ and 400-500 r / min for 30-40 min. Then, boric acid-modified chitosan solution was added and stirring was continued for 1-2 h. The mixture was heated to 70-80℃ and stirred for 30-40 min. After naturally cooling to room temperature, the mixture was filtered, washed, and vacuum dried to obtain boric acid-modified porous nanospheres.

7. The flame-retardant flexible control cable with electromagnetic interference resistance according to claim 6, characterized in that, The ratio of isooctane, Span 85 and boric acid-modified chitosan solution is 50-60 kg: 5-6 kg: 8-9 kg.

8. The flame-retardant flexible control cable with electromagnetic interference resistance according to claim 6, characterized in that, The boric acid-modified chitosan solution was prepared through the following steps: Chitosan powder and 1 wt% acetic acid solution were added to a reaction vessel and stirred to dissolve. Then 4-aminophenylboronic acid was added, and the mixture was stirred at 20-25℃ and 400-500 r / min for 6-7 h. The mixture was then filtered, washed, and vacuum dried to obtain boric acid modified chitosan powder. Boric acid-modified chitosan powder, 4-5 wt% lithium hydroxide solution, 6-7 wt% sodium hydroxide solution and 7-8 wt% urea solution are added to a reaction vessel and stirred at 30-35℃ and 400-500 r / min for 30-40 min to obtain boric acid-modified chitosan solution. The ratio of chitosan powder, acetic acid solution, and 4-aminophenylboronic acid is 1-2 kg: 7-8 L: 3-4 kg; the ratio of boric acid-modified chitosan powder, lithium hydroxide solution, sodium hydroxide solution, and urea solution is 1-2 kg: 6-7 kg: 6-7 kg: 6-7 kg.

9. The flame-retardant flexible control cable with electromagnetic interference resistance according to claim 1, characterized in that, The specific steps of the porous carbon / nanosheet composite described in step three are as follows: The composite porous precursor was transferred to a muffle furnace and heated to 300-400°C under argon protection at a heating rate of 10-12°C / min. The argon gas was then stopped, and ammonia gas was introduced at a heating rate of 20-25°C / min to heat to 900-1000°C. The temperature was maintained for 2-3 hours, and the mixture was allowed to cool naturally. The product was then added to a 1 mol / L hydrochloric acid solution and ultrasonically washed for 4-5 hours. The mixture was then filtered, washed, and vacuum dried to obtain the porous carbon / nanosheet composite.

10. The flame-retardant flexible control cable with electromagnetic interference resistance according to claim 1, characterized in that, In step four, the ratio of polyvinyl chloride, diisodecyl phthalate, triphenyl phosphate, porous carbon / nanosheet composite, zinc borate nanosheet composite porous vermiculite, and calcium-zinc stabilizer is 9-10 kg: 1-2 kg: 800-900 g: 500-600 g: 300-400 g: 40-80 g.

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