Halogen-free low-smoke flame-retardant degaussing cable for ships

Abstract

The invention discloses a halogen-free low-smoke flame-retardant degaussing cable for ships, and the cable comprises a copper conductor, the outer layer of the copper conductor is sleeved with an insulating layer, and the outer layer of the insulating layer is sleeved with a degaussing flame-retardant composite layer. The degaussing flame-retardant composite layer is prepared from a degaussing flame-retardant composite material; the degaussing flame-retardant composite material comprises the following raw materials in parts by mass: 100 parts of an ethylene-vinyl acetate copolymer, 15-20 parts of nano nickel-zinc ferrite, 60-80 parts of a modified flame retardant, 10-15 parts of red phosphorus microcapsules and 3-5 parts of nano montmorillonite, and the halogen-free low-smoke flame-retardant degaussing cable for ships and warships provided by the invention is a halogen-free low-smoke flame-retardant degaussing cable for ships and warships. Through the multistage flame-retardant system design and the nano ferrite degaussing integration and interface synergistic strengthening process, synergistic optimization of halogen-free, low-smoke, high-flame-retardant and degaussing functions of the ship cable is realized, and compared with the traditional technology, the ship cable is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of cable production, and particularly relates to a halogen-free, low-smoke, flame-retardant and degaussing cable for ships. Background Art

[0002] Ship cables need to operate stably in a complex electromagnetic environment for a long time and meet high safety standards at the same time. Since the ship cabins are enclosed and it is difficult to escape, the cables must have the characteristics of being halogen-free, low-smoke and flame-retardant to avoid releasing toxic gases and thick smoke when burning. In addition, ship electronic equipment is sensitive to electromagnetic interference, and the cables must have a degaussing function to reduce the interference of their own magnetic field on the navigation and communication systems.

[0003] Existing cables mostly use polyvinyl chloride (PVC) sheaths, which contain halogens and release toxic gases such as hydrogen chloride when burning, and have a low oxygen index (about 22-25). Although some technologies improve the performance by adding flame retardants, they still cannot meet the requirements of being halogen-free and low-smoke. In addition, existing cables lack a degaussing design and cannot suppress magnetic field interference.

[0004] The ship safety specifications are becoming increasingly strict, and there is an urgent need for a cable with the functions of being halogen-free, low-smoke, highly flame-retardant and degaussing. The single-performance improvement in the existing technology cannot meet the comprehensive requirements, and there is an urgent need for improvement and innovation. Summary of the Invention

[0005] The purpose of the present invention is to provide a cable with the functions of being halogen-free, low-smoke, highly flame-retardant and degaussing.

[0006] The purpose of the present invention can be achieved by the following technical solutions: A halogen-free, low-smoke, flame-retardant and degaussing cable for ships, comprising a copper conductor, an insulating layer sleeved outside the copper conductor, and a degaussing and flame-retardant composite layer sleeved outside the insulating layer; The degaussing and flame-retardant composite layer is prepared from a degaussing and flame-retardant composite material; The degaussing and flame-retardant composite material comprises the following raw materials in parts by mass: 100 parts of ethylene-vinyl acetate copolymer, 15-20 parts of nano nickel-zinc ferrite, 60-80 parts of modified flame retardant, 10-15 parts of red phosphorus microcapsule, 3-5 parts of nano montmorillonite.

[0007] Further, the nano nickel-zinc ferrite is prepared by the following steps: Dissolve Fe(NO3)3∙9H2O, Zn(NO3)2∙6H2O, and Ni(NO3)2∙6H2O in deionized water, stir at room temperature for 30 min, then add citric acid monohydrate and stir for 30 min. Then, add ammonia water to adjust the pH value of the solution to 4.0 - 4.2. Then, place it at 90 - 95 °C and stir until a dark green viscous wet sol is formed. After aging at room temperature and drying with hot air, a dry gel is obtained. The dry gel is then heated to 400 - 420 °C and kept warm for 2 - 3 h, then heated to 1000 - 1050 °C and kept warm for 4 - 5 h. After cooling and grinding through a 100-mesh sieve, nano nickel-zinc ferrite is obtained.

[0008] Furthermore, the dosage ratio of Fe(NO3)3∙9H2O, Zn(NO3)2∙6H2O, Ni(NO3)2∙6H2O, deionized water, and citric acid monohydrate is 0.2 mol:0.05 mol:0.05 mol:800 - 1000 mL:0.45 - 0.50 mol.

[0009] Furthermore, the modified flame retardant is prepared by the following steps: A1. Mix Al(OH)3 and Mg(OH)2 in a mass ratio of 7:3, then add a 10% phosphoric acid solution thereto according to a solid-liquid ratio of 1:10, perform ultrasonic treatment at 60 °C for 1 hour, then mechanically stir at 60 °C for 2 hours. After completion, centrifuge and separate at 8000 rpm for 10 minutes, wash with deionized water until neutral, and vacuum dry at 80 °C for 6 hours to obtain porous Al / Mg-OH; A2. Disperse the porous Al / Mg-OH in absolute ethanol according to a solid-liquid ratio of 1:5, then add KH-570 accounting for 2% - 5% of the mass of the porous Al / Mg-OH thereto, perform ultrasonic treatment at 60 °C for 30 minutes, then raise the temperature to 80 °C and mechanically stir and react for 3 hours. After completion, centrifuge and wash 3 times, and vacuum dry at 60 °C to obtain Al / Mg-OH@Si; A3. Premix Al / Mg-OH@Si, maleic anhydride, and dicumyl peroxide, add them to a twin-screw extruder, with a screw speed of 200 rpm and a residence time of 5 minutes. After completion, extrude and pelletize, and pass through a 40-mesh sieve after cooling to obtain the modified flame retardant.

[0010] Furthermore, the mass ratio of Al / Mg-OH@Si, maleic anhydride, and dicumyl peroxide in A3 is 100:3:0.5.

[0011] Furthermore, the red phosphorus microcapsule is prepared by the following steps: B1. Add red phosphorus powder and KH-570 into absolute ethanol, ultrasonically disperse for 30 minutes, then under nitrogen protection, stir and react at 60 °C for 2 hours, then carry out centrifugal separation, wash with ethanol 3 times, and vacuum dry at 80 °C for 6 hours to obtain silanized red phosphorus; B2. First, react melamine with 75% - 80% of the total amount of 37% formaldehyde solution at pH 8.5 and 65 °C for 40 - 60 minutes to form a melamine-formaldehyde prepolymer. Then add silanized red phosphorus into the above melamine-formaldehyde prepolymer, and then add polyvinyl alcohol and nano-silica into it, ultrasonically disperse for 20 minutes, then raise the temperature to 75 - 78 °C, adjust the pH to 5.0 - 5.5, and stir and react at a constant temperature for 1 hour. Then add the remaining 37% formaldehyde solution, adjust the pH to 4.0 - 4.2, and react at 80 - 85 °C for 1.5 hours. After completion, filter, wash with deionized water until neutral, and vacuum dry at 60 °C for 12 hours to obtain red phosphorus microcapsules.

[0012] Further, the mass ratio of the red phosphorus powder, KH-570 and absolute ethanol in B1 is 100:3 - 4:200.

[0013] Further, the mass ratio of the melamine, 37% formaldehyde solution, silanized red phosphorus, polyvinyl alcohol, and nano-silica in B1 is 15:40 - 50:50:2 - 3:5.

[0014] Further, the preparation process of the degaussing flame retardant composite material includes the following steps: Weigh the raw materials ethylene-vinyl acetate copolymer, nano-nickel zinc ferrite, modified flame retardant, red phosphorus microcapsules and nano-montmorillonite according to parts by mass. Then add the ethylene-vinyl acetate copolymer, modified flame retardant, red phosphorus microcapsules, and nano-montmorillonite into a high-speed mixer for premixing for 10 minutes, then add nano-nickel zinc ferrite and diisopropylbenzene peroxide, and continue to mix for 5 minutes to obtain a mixed material. Then transfer the mixed material to a solvent dispersion tank, add absolute ethanol according to a solid-liquid ratio of 1:3, ultrasonically treat for 20 minutes, and then carry out vacuum desolvation at 60 °C to obtain a solid material. Place the solid material in a twin-screw extruder for melt co-extrusion, and then through granulation and annealing, obtain the degaussing flame retardant composite material.

[0015] Further, the temperature gradient setting of the twin-screw extruder is as follows: melting section: 170 - 180 °C, homogenizing section: 175 °C, screw speed: 250 rpm, vacuum degree: -0.08 MPa.

[0016] The beneficial effects of the present invention: Through the design of a multi-level flame retardant system, the integration of nano-ferrite demagnetization, and the interface synergistic strengthening process, the present invention realizes the collaborative optimization of the halogen-free, low-smoke, high flame retardant, and demagnetization functions of ship cables, showing significant improvements compared to traditional technologies. The following is a detailed analysis based on data: 1. Substantial breakthrough in high flame retardant performance: The oxygen index (OI) is increased to 48.3% (Example 14), which is a 53.0% increase compared to 31.5% in Comparative Example 7 (unmodified Al / Mg-OH), far exceeding the IMO requirement of ≥35% for the oxygen index of halogen-free cables.

[0017] Technical root cause: The modified flame retardant (Al / Mg-OH@Si-MAH) forms a porous structure through phosphoric acid etching, increasing the contact area between the flame retardant and the matrix; the silane coupling agent (KH-570) and maleic anhydride (MAH) grafting enhance the interfacial bonding, increasing the flame retardancy efficiency by 34.8%. At the same time, the microencapsulated red phosphorus (MCA-P) and the modified flame retardant form a "gas phase - condensed phase" dual-mechanism flame retardancy.

[0018] 2. Significant improvement in low-smoke performance: The smoke density (Ds) is reduced to 79.8 Ds (Example 14), which is an 81.9% decrease compared to 440 Ds in Comparative Example 7, meeting the IMO low-smoke standard (≤150 Ds).

[0019] Technical root cause: The intercalated structure of nano-montmorillonite (layer spacing 2.8 nm) adsorbs combustion free radicals, inhibiting smoke generation; nano-nickel-zinc ferrite (Ni0.5Zn0.5Fe2O4) catalyzes the combustion residues to form a dense carbon layer, reducing the smoke density by 73.0% compared to Comparative Example 6 (without ferrite). At the same time, the smoke density of Comparative Example 10 (only silanized red phosphorus) is 180 Ds, proving that the MF resin gradient coating (Example 14) further suppresses smoke.

[0020] 3. Breakthrough integration of demagnetization function: The magnetic field attenuation rate (MAR) reaches 70.2% (Example 14), which is a 254.5% increase compared to 19.8% in Comparative Example 6 (without ferrite), meeting the ship electromagnetic compatibility standard (GJB1916).

[0021] Technical root cause: Nano-nickel-zinc ferrite (particle size 50 nm) is prepared by the sol-gel method to form a uniform magnetic loss network. At the same time, the compatibility between the ferrite and the EVA matrix is optimized through silane coupling (KH-550) to avoid agglomeration.

[0022] 4. Synergistic strengthening of mechanical properties: The tensile strength reaches 15.8 MPa (Example 14), which is a 154.8% increase compared to 6.2 MPa in Comparative Example 7, significantly higher than that of traditional halogen-free cables (8 - 10 MPa).

[0023] Technical origin: The dynamic crosslinking process (DCP-initiated EVA-MAH grafting) forms a chemical bonding interface. Among them, the tensile strength of Comparative Example 3 (only porous Al / Mg-OH) is 8.5 MPa, proving that the silane coupling and MAH grafting increase the strength by 85.9%.

[0024] Summary: Through three major innovations, namely multi-stage flame retardancy-smoke suppression design, construction of nano-ferrite magnetic network, and strengthening of interfacial chemical bonding, the present invention solves the long-existing technical problem of "difficulty in coordinating flame retardancy-demagnetization-mechanical properties" in the field of ship cables. In summary, through material innovation and process optimization, the present invention realizes a leapfrog improvement in the comprehensive performance of ship cables and has extremely high industrial practicability. Detailed implementation mode

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] Example 1

[0027] Preparation of nano nickel-zinc ferrite: Dissolve 0.2 mol of Fe(NO3)3∙9H2O, 0.05 mol of Zn(NO3)2∙6H2O, and 0.05 mol of Ni(NO3)2∙6H2O in 800 mL of deionized water, then continuously stir with a magnetic stirrer at room temperature for 30 min until completely dissolved and a homogeneous solution is formed. Then add 0.45 mol of citric acid monohydrate to the solution and continue stirring for 30 min. After all the citric acid monohydrate is dissolved, continue stirring and dropwise add ammonia water to adjust the pH value of the solution to 4.0. Then transfer the solution to an oil bath and stir at 90 °C until a dark green viscous wet sol is formed. Take it out and age it at room temperature for 2 h. Then transfer the gel to a forced-air drying oven and heat it to 100 °C for 12 h to transform the wet sol into a puffy dry gel. Finally, transfer the dry gel to a muffle furnace, heat it to 400 °C and keep it warm for 2 h to remove nitrate ions and other ions in the gel, then heat it to 1000 °C and keep it warm for 4 h. After the sample cools down, take it out and grind it through a 100-mesh sieve to obtain brown nano nickel-zinc ferrite (Ni 0.5 Zn 0.5 Fe2O4).

[0028] Example 2

[0029] Preparation of nano nickel-zinc ferrite: Dissolve 0.2 mol of Fe(NO3)3∙9H2O, 0.05 mol of Zn(NO3)2∙6H2O, and 0.05 mol of Ni(NO3)2∙6H2O in 800 mL of deionized water. Then, continuously stir the solution for 30 min at room temperature using a magnetic stirrer until it is completely dissolved and a homogeneous solution is formed. Next, add 0.50 mol of citric acid monohydrate to the solution and continue stirring for 30 min. After the citric acid monohydrate is completely dissolved, continue stirring and add ammonia water dropwise to adjust the pH value of the solution to 4.0. Then, transfer the solution to an oil bath and stir at 95 °C until a dark green viscous wet sol is formed. Take it out and age it at room temperature for 4 h. Then, transfer the gel to a forced-air drying oven and heat it to 110 °C for 12 h to transform the wet sol into a puffy dry gel. Finally, transfer the dry gel to a muffle furnace, heat it to 410 °C and hold for 3 h to remove nitrate ions and other ions in the gel. Then, heat it to 1050 °C and hold for 5 h. After the sample cools down, take it out and grind it through a 100-mesh sieve to obtain brown nano nickel-zinc ferrite (Ni 0.5 Zn 0.5 Fe2O4).

[0030] Example 3

[0031] Preparation of nano nickel-zinc ferrite: Dissolve 0.2 mol of Fe(NO3)3∙9H2O, 0.05 mol of Zn(NO3)2∙6H2O, and 0.05 mol of Ni(NO3)2∙6H2O in 1000 mL of deionized water. Then, continuously stir the solution for 30 min at room temperature using a magnetic stirrer until it is completely dissolved and a homogeneous solution is formed. Next, add 0.50 mol of citric acid monohydrate to the solution and continue stirring for 30 min. After the citric acid monohydrate is completely dissolved, continue stirring and add ammonia water dropwise to adjust the pH value of the solution to 4.2. Then, transfer the solution to an oil bath and stir at 95 °C until a dark green viscous wet sol is formed. Take it out and age it at room temperature for 4 h. Then, transfer the gel to a forced-air drying oven and heat it to 120 °C for 12 h to transform the wet sol into a puffy dry gel. Finally, transfer the dry gel to a muffle furnace, heat it to 420 °C and hold for 3 h to remove nitrate ions and other ions in the gel. Then, heat it to 1050 °C and hold for 5 h. After the sample cools down, take it out and grind it through a 100-mesh sieve to obtain brown nano nickel-zinc ferrite (Ni 0.5 Zn 0.5 Fe2O4).

[0032] Example 4

[0033] Preparation of modified flame retardant: Phosphoric acid etching: Mix Al(OH)3 and Mg(OH)2 at a mass ratio of 7:3, add a 10% phosphoric acid solution (solid-liquid ratio 1:10), ultrasonically treat for 1 hour at 60 °C (power 400 W), then mechanically stir at 60 °C for 2 hours. During the above process, phosphoric acid selectively etches the surface of Al(OH)3 / Mg(OH)2 to form a honeycomb-like porous structure, enhancing the subsequent silane grafting efficiency. After completion, centrifuge separation (8000 rpm, 10 minutes), wash with deionized water until neutral, and vacuum dry at 80 °C for 6 hours to obtain porous Al / Mg-OH; Silane coupling modification: Disperse porous Al / Mg-OH in absolute ethanol (solid-liquid ratio 1:5), then add KH-570 accounting for 2% of the mass of porous Al / Mg-OH, ultrasonically treat for 30 minutes at 60 °C, then raise the temperature to 80 °C, and mechanically stir (1200 rpm) for 3 hours. During the above process, the silanol groups formed after the hydrolysis of KH-570 condense with the surface hydroxyl groups of porous Al / Mg-OH to form covalent bonds. After the hydrolysis of KH-570, the terminal methacryloxy groups are exposed, providing active sites for subsequent MAH grafting. After completion, centrifuge and wash 3 times, and vacuum dry at 60 °C to obtain Al / Mg-OH@Si; Maleic anhydride dynamic grafting: Premix Al / Mg-OH@Si, maleic anhydride, and diisopropylbenzene peroxide at a mass ratio of 100:3:0.5, add them to a twin-screw extruder, set the temperature gradient: feeding section 150 °C, melting section 175 °C, homogenization section 170 °C, screw speed 200 rpm, residence time 5 minutes. During the above process, diisopropylbenzene peroxide initiates the free radical polymerization of maleic anhydride, and undergoes graft copolymerization with the methacryloxy groups on the surface of Al / Mg-OH@Si to form a double interfacial bond of ester bond and hydrogen bond, improving the compatibility between the modified flame retardant and the ethylene-vinyl acetate copolymer matrix. After completion, extrude and pelletize, and pass through a 40-mesh sieve after cooling to obtain the modified flame retardant.

[0034] Example 5

[0035] Preparation of modified flame retardant: Phosphoric acid etching: Mix Al(OH)3 and Mg(OH)2 at a mass ratio of 7:3, add a 10% phosphoric acid solution (solid-liquid ratio 1:10), ultrasonically treat for 1 hour at 60 °C (power 400 W), then mechanically stir at 60 °C for 2 hours. During the above process, phosphoric acid selectively etches the surface of Al(OH)3 / Mg(OH)2 to form a honeycomb-like porous structure, enhancing the subsequent silane grafting efficiency. After completion, centrifuge separation (8000 rpm, 10 minutes), wash with deionized water until neutral (pH 7.0 ± 0.2), and vacuum dry at 80 °C for 6 hours to obtain porous Al / Mg-OH; Silane coupling modification: Dispersed porous Al / Mg-OH in absolute ethanol (solid-liquid ratio 1:5), then added KH-570 accounting for 5% of the mass of porous Al / Mg-OH, ultrasonicated at 60 °C for 30 minutes, then heated to 80 °C, and reacted under mechanical stirring (1200 rpm) for 3 hours. During the above process, the silanol groups formed after the hydrolysis of KH-570 condensed with the surface hydroxyl groups of porous Al / Mg-OH to form covalent bonds. After the hydrolysis of KH-570, the terminal methacryloyloxy groups were exposed, providing active sites for subsequent MAH grafting. After completion, centrifuged and washed 3 times, and dried in vacuum at 60 °C to obtain Al / Mg-OH@Si; Maleic anhydride dynamic grafting: Premixed Al / Mg-OH@Si, maleic anhydride, and diisopropylbenzene peroxide in a mass ratio of 100:3:0.5, added into a twin-screw extruder, set the temperature gradient: feeding section 155 °C, melting section 175 °C, homogenization section 170 °C, screw speed 200 rpm, residence time 5 minutes. During the above process, diisopropylbenzene peroxide initiated the free radical polymerization of maleic anhydride, and graft copolymerization occurred with the methacryloyloxy groups on the surface of Al / Mg-OH@Si, forming a dual interfacial combination of ester bonds and hydrogen bonds, improving the compatibility between the modified flame retardant and the ethylene-vinyl acetate copolymer matrix. After completion, extruded and pelletized, and passed through a 40-mesh sieve after cooling to obtain the modified flame retardant.

[0036] Example 6

[0037] Preparation of modified flame retardant: Phosphoric acid etching: Mixed Al(OH)3 and Mg(OH)2 in a mass ratio of 7:3, added a phosphoric acid solution with a mass fraction of 10% (solid-liquid ratio 1:10), ultrasonicated at 60 °C for 1 hour (power 400 W), and then mechanically stirred at 60 °C for 2 hours. During the above process, phosphoric acid selectively etched the surface of Al(OH)3 / Mg(OH)2 to form a honeycomb-like porous structure, enhancing the subsequent silane grafting efficiency. After completion, centrifuged and separated (8000 rpm, 10 minutes), washed with deionized water until neutral (pH 7.0 ± 0.2), and dried in vacuum at 80 °C for 6 hours to obtain porous Al / Mg-OH; Silane coupling modification: Dispersed porous Al / Mg-OH in absolute ethanol (solid-liquid ratio 1:5), then added KH-570 accounting for 5% of the mass of porous Al / Mg-OH, ultrasonicated at 60 °C for 30 minutes, then heated to 80 °C, and reacted under mechanical stirring (1200 rpm) for 3 hours. During the above process, the silanol groups formed after the hydrolysis of KH-570 condensed with the surface hydroxyl groups of porous Al / Mg-OH to form covalent bonds. After the hydrolysis of KH-570, the terminal methacryloyloxy groups were exposed, providing active sites for subsequent MAH grafting. After completion, centrifuged and washed 3 times, and dried in vacuum at 60 °C to obtain Al / Mg-OH@Si; Maleic anhydride dynamic grafting: Premix Al / Mg-OH@Si, maleic anhydride, and diisopropylbenzene peroxide according to a mass ratio of 100:3:0.5, add them to a twin-screw extruder, and set the temperature gradient: the feeding section is 160 °C, the melting section is 180 °C, the homogenization section is 175 °C, the screw speed is 200 rpm, and the residence time is 5 minutes. During the above process, diisopropylbenzene peroxide initiates the free radical polymerization of maleic anhydride, and undergoes graft copolymerization with the methacryloyloxy groups on the surface of Al / Mg-OH@Si to form a double interfacial bond of ester bonds and hydrogen bonds, improving the compatibility between the modified flame retardant and the ethylene-vinyl acetate copolymer matrix. After completion, extrude and pelletize, and pass through a 40-mesh sieve after cooling to obtain the modified flame retardant.

[0038] Example 7

[0039] Preparation of red phosphorus microcapsules: Pre-modification of the surface of red phosphorus (to improve dispersibility): Add red phosphorus powder (purity 99%, particle size 10 μm) and KH-570 to anhydrous ethanol. Among them, the mass ratio of red phosphorus powder, KH-570, and anhydrous ethanol is 100:3:200. Ultrasonically disperse for 30 minutes (power 500 W, frequency 28 kHz), then under nitrogen protection, stir and react at 60 °C for 2 hours to hydrolyze KH-570 and graft it onto the surface of red phosphorus. Then, centrifuge and wash with ethanol 3 times, and vacuum dry at 80 °C for 6 hours to obtain silanized red phosphorus (Si-P); Gradient coating of melamine-formaldehyde (MF) resin (to inhibit the release of PH3): First, stir and react 15 parts (by mass, the same below) of melamine with 30 parts of formaldehyde solution (37%) at pH 8.5 (adjusted with ammonia water) and 65 °C for 40 minutes to form a melamine-formaldehyde prepolymer. Then, add 50 parts of silanized red phosphorus to the above melamine-formaldehyde prepolymer, and then add 2 parts of the dispersant polyvinyl alcohol and 5 parts of nano-silica (particle size 20 nm, specific surface area 200 m 2 / g), ultrasonically disperse for 20 minutes (power 400 W), then raise the temperature to 75 °C, adjust the pH to 5.0 (adjusted with citric acid), and stir and react at a constant temperature for 1 hour to form a melamine-formaldehyde coating layer on the surface of silanized red phosphorus. Then, add an additional 10 parts of formaldehyde solution (37%) thereto, adjust the pH to 4.0 (adjusted with citric acid), and react at 80 °C for 1.5 hours to form a rough second coating layer structure on the outer layer of the above melamine-formaldehyde coating layer, enhancing the mechanical anchoring effect between the red phosphorus microcapsules and the matrix ethylene-vinyl acetate copolymer. After completion, filter, wash with deionized water until neutral, and vacuum dry at 60 °C for 12 hours to obtain red phosphorus microcapsules.

[0040] Example 8

[0041] Preparation of red phosphorus microcapsules: Surface pre-modification of red phosphorus (to improve dispersibility): Add red phosphorus powder (purity 99%, particle size 10 μm) and KH-570 into absolute ethanol. Among them, the mass ratio of red phosphorus powder, KH-570 and absolute ethanol is 100:4:200. Ultrasonically disperse for 30 minutes (power 500 W, frequency 30 kHz), then under nitrogen protection, stir and react at 60 °C for 2 hours to hydrolyze KH-570 and graft it onto the surface of red phosphorus. Then, after centrifugal separation, wash with ethanol three times and vacuum dry at 80 °C for 6 hours to obtain silanized red phosphorus (Si-P); Gradient coating of melamine-formaldehyde (MF) resin (to inhibit PH3 release): First, add 15 parts (parts by mass, the same below) of melamine and 35 parts of formaldehyde solution (37%) and stir and react at pH 8.5 (adjusted with ammonia water) and 65 °C for 60 minutes to form a melamine-formaldehyde prepolymer. Then, add 50 parts of silanized red phosphorus into the above melamine-formaldehyde prepolymer, and then add 3 parts of dispersant polyvinyl alcohol and 5 parts of nano-silica (particle size 20 nm, specific surface area 200 m 2 / g), ultrasonically disperse for 20 minutes (power 400 W), then raise the temperature to 77 °C, adjust the pH to 5.0 (adjusted with citric acid), and stir and react at a constant temperature for 1 hour to form a melamine-formaldehyde coating layer on the surface of silanized red phosphorus. Then, add 10 parts of formaldehyde solution (37%) thereto, adjust the pH to 4.0 (adjusted with citric acid), and react at 84 °C for 1.5 hours to form a rough second coating layer structure on the outer layer of the above melamine-formaldehyde coating layer, enhancing the mechanical anchoring effect between the red phosphorus microcapsule and the matrix ethylene-vinyl acetate copolymer. After completion, filter, wash with deionized water until neutral, and vacuum dry at 60 °C for 12 hours to obtain red phosphorus microcapsules.

[0042] Example 9

[0043] Preparation of red phosphorus microcapsules: Surface pre-modification of red phosphorus (to improve dispersibility): Add red phosphorus powder (purity 99%, particle size 10 μm) and KH-570 into absolute ethanol. Among them, the mass ratio of red phosphorus powder, KH-570 and absolute ethanol is 100:4:200. Ultrasonically disperse for 30 minutes (power 500 W, frequency 30 kHz), then under nitrogen protection, stir and react at 60 °C for 2 hours to hydrolyze KH-570 and graft it onto the surface of red phosphorus. Then, after centrifugal separation, wash with ethanol three times and vacuum dry at 80 °C for 6 hours to obtain silanized red phosphorus (Si-P); Melamine - formaldehyde (MF) resin gradient coating (inhibiting PH3 release): First, 15 parts (by mass, the same below) of melamine and 40 parts of formaldehyde solution (37%) are stirred and reacted at pH 8.5 (adjusted with ammonia water) and 65 °C for 60 minutes to form a melamine - formaldehyde prepolymer. Then, 50 parts of silanized red phosphorus are added to the above melamine - formaldehyde prepolymer, and then 3 parts of dispersant polyvinyl alcohol and 5 parts of nano - silica (particle size 20 nm, specific surface area 200 m 2 / g) are added thereto. After ultrasonic dispersion for 20 minutes (power 400 W), the temperature is raised to 78 °C, and the pH is adjusted to 5.5 (adjusted with citric acid). Then, it is stirred and reacted at a constant temperature for 1 hour to form a melamine - formaldehyde coating layer on the surface of the silanized red phosphorus. Then, 10 parts of formaldehyde solution (37%) are added thereto, the pH is adjusted to 4.2 (adjusted with citric acid), and it is reacted at 85 °C for 1.5 hours to form a rough second coating layer structure on the outer layer of the above melamine - formaldehyde coating layer, enhancing the mechanical anchoring effect between the red phosphorus microcapsules and the matrix ethylene - vinyl acetate copolymer. After completion, it is filtered, washed with deionized water until neutral, and dried in vacuum at 60 °C for 12 hours to obtain red phosphorus microcapsules.

[0044] Example 10

[0045] Preparation of demagnetized flame - retardant composite material: First, the demagnetized flame - retardant composite material comprises the following raw materials in parts by mass: 100 parts of ethylene - vinyl acetate copolymer (EVA, vinyl acetate content 28%, melt flow rate 2 g / 10 min), 15 parts of the nano - nickel - zinc ferrite prepared in Example 1, 60 parts of the modified flame retardant prepared in Example 4, 10 parts of the red phosphorus microcapsules prepared in Example 7, and 3 parts of nano - montmorillonite.

[0046] Then, the preparation process of the demagnetized flame - retardant composite material comprises the following steps: Weigh the raw materials ethylene-vinyl acetate copolymer, the nano nickel-zinc ferrite prepared in Example 1, the modified flame retardant prepared in Example 4, the red phosphorus microcapsule prepared in Example 7 and nano-montmorillonite according to parts by mass. Then, add the ethylene-vinyl acetate copolymer, the modified flame retardant prepared in Example 4, the red phosphorus microcapsule prepared in Example 7 and nano-montmorillonite into a high-speed mixer (rotation speed 1200 rpm), premix for 10 minutes, then add the nano nickel-zinc ferrite prepared in Example 1 and dicumyl peroxide, and continue to mix for 5 minutes to obtain a mixed material. Then, transfer the mixed material to a solvent dispersion tank, add absolute ethanol (solid-liquid ratio 1:3), perform ultrasonic treatment (power 800 W, frequency 40 kHz) for 20 minutes, and then place it in a vacuum for desolvation at 60 °C to obtain a solid material. Place the solid material in a twin-screw extruder (length-diameter ratio 40:1) for melt co-extrusion, and then through pelletizing and annealing, a demagnetizing flame-retardant composite material is obtained. Among them, the temperature gradient of the twin-screw extruder is set as follows: melting section: 170 °C, homogenization section: 175 °C, screw rotation speed: 250 rpm, vacuum degree: -0.08 MPa. In the above process, dicumyl peroxide initiates a graft reaction between the ethylene-vinyl acetate copolymer and the MAH groups on the surface of the modified flame retardant prepared in Example 4 to form a chemical bond, and the porous MF shell of the red phosphorus microcapsule prepared in Example 7 generates mechanical interlocking with the ethylene-vinyl acetate copolymer melt.

[0047] Example 11

[0048] Prepare a demagnetizing flame-retardant composite material: First of all, the demagnetizing flame-retardant composite material comprises the following raw materials by parts by mass: 100 parts of ethylene-vinyl acetate copolymer (EVA, vinyl acetate content 28%, melt flow rate 2 g / 10 min), 20 parts of the nano nickel-zinc ferrite prepared in Example 2, 80 parts of the modified flame retardant prepared in Example 5, 15 parts of the red phosphorus microcapsule prepared in Example 8, 5 parts of nano-montmorillonite.

[0049] Then, the preparation process of the demagnetizing flame-retardant composite material comprises the following steps: Weigh the raw materials ethylene-vinyl acetate copolymer, nano nickel-zinc ferrite prepared in Example 2, modified flame retardant prepared in Example 5, red phosphorus microcapsule prepared in Example 8 and nano-montmorillonite according to parts by mass. Then, add the ethylene-vinyl acetate copolymer, modified flame retardant prepared in Example 5, red phosphorus microcapsule prepared in Example 8 and nano-montmorillonite to a high-speed mixer (rotating speed 1200 rpm), premix for 10 minutes, then add the nano nickel-zinc ferrite prepared in Example 2 and dicumyl peroxide, and continue to mix for 5 minutes to obtain a mixed material. Then, transfer the mixed material to a solvent dispersion tank, add absolute ethanol (solid-liquid ratio 1:3), and perform ultrasonic treatment (power 800 W, frequency 40 kHz) for 20 minutes, and then place it in a vacuum for desolvation at 60 °C to obtain a solid material. Place the solid material in a twin-screw extruder (length-diameter ratio 40:1) for melt co-extrusion, and then through granulation and annealing, a demagnetizing flame-retardant composite material is obtained. Among them, the temperature gradient of the twin-screw extruder is set as follows: melting section: 175 °C, homogenization section: 175 °C, screw rotation speed: 250 rpm, vacuum degree: -0.08 MPa. In the above process, dicumyl peroxide initiates a graft reaction between the ethylene-vinyl acetate copolymer and the MAH groups on the surface of the modified flame retardant prepared in Example 5 to form a chemical bond, and the porous MF shell of the red phosphorus microcapsule prepared in Example 8 generates mechanical interlocking with the ethylene-vinyl acetate copolymer melt.

[0050] Example 12

[0051] Preparation of demagnetizing flame-retardant composite material: First, the demagnetizing flame-retardant composite material comprises the following raw materials in parts by mass: 100 parts of ethylene-vinyl acetate copolymer (EVA, vinyl acetate content 28%, melt flow rate 2 g / 10 min), 20 parts of nano nickel-zinc ferrite prepared in Example 3, 80 parts of modified flame retardant prepared in Example 6, 15 parts of red phosphorus microcapsule prepared in Example 9, 5 parts of nano-montmorillonite.

[0052] Then, the preparation process of the demagnetizing flame-retardant composite material comprises the following steps: Weigh the raw materials ethylene-vinyl acetate copolymer, the nano nickel-zinc ferrite prepared in Example 3, the modified flame retardant prepared in Example 6, the red phosphorus microcapsule prepared in Example 9, and nano-montmorillonite according to mass parts. Then add the ethylene-vinyl acetate copolymer, the modified flame retardant prepared in Example 6, the red phosphorus microcapsule prepared in Example 9, and nano-montmorillonite to a high-speed mixer (rotating speed 1200 rpm), premix for 10 minutes, then add the nano nickel-zinc ferrite prepared in Example 3 and dicumyl peroxide, and continue to mix for 5 minutes to obtain a mixed material. Then transfer the mixed material to a solvent dispersion tank, add absolute ethanol (solid-liquid ratio 1:3), perform ultrasonic treatment (power 800 W, frequency 40 kHz) for 20 minutes, and then place it in a vacuum for desolvation at 60 °C to obtain a solid material. Place the solid material in a twin-screw extruder (length-diameter ratio 40:1) for melt co-extrusion, and then through granulation and annealing, a demagnetizing flame retardant composite material is obtained. Among them, the temperature gradient of the twin-screw extruder is set as follows: melting section: 180 °C, homogenizing section: 175 °C, screw rotating speed: 250 rpm, vacuum degree: -0.08 MPa. In the above process, dicumyl peroxide initiates a graft reaction between the ethylene-vinyl acetate copolymer and the MAH groups on the surface of the modified flame retardant prepared in Example 6 to form a chemical bond, and the porous MF shell of the red phosphorus microcapsule prepared in Example 9 mechanically interlocks with the ethylene-vinyl acetate copolymer melt.

[0053] Comparative Example 1 Comparative Example 1 is the control group of Example 11. Delete 20 parts of the nano nickel-zinc ferrite prepared in Example 2 in the raw materials of Example 11, and keep the rest of the raw materials, the amounts of raw materials, and the preparation steps the same as those in Example 11, and finally obtain a flame retardant composite material.

[0054] Comparative Example 2 Comparative Example 2 is the control group of Example 11. Replace the modified flame retardant prepared in Example 5 in the raw materials of Example 11 with the raw materials in Example 5 (a mixture of Al(OH)3 and Mg(OH)2 in a mass ratio of 7:3), and keep the rest of the raw materials, the amounts of raw materials, and the preparation steps the same as those in Example 11, and finally obtain a demagnetizing flame retardant composite material.

[0055] Comparative Example 3 Comparative Example 3 is the control group of Example 11. Replace the modified flame retardant prepared in Example 5 in the raw materials of Example 11 with the porous Al / Mg-OH in Example 5, and keep the rest of the raw materials, the amounts of raw materials, and the preparation steps the same as those in Example 11, and finally obtain a demagnetizing flame retardant composite material.

[0056] Comparative Example 4 Comparative Example 4 is the control group of Example 11. The red phosphorus microcapsules prepared in Example 8 in the raw materials of Example 11 were replaced with red phosphorus powder (purity 99%, particle size 10 μm), and the remaining raw materials, raw material dosages, and preparation steps were kept the same as those in Example 11, and finally a demagnetized flame-retardant composite material was obtained.

[0057] Comparative Example 5 Comparative Example 5 is the control group of Example 11. The red phosphorus microcapsules prepared in Example 8 in the raw materials of Example 11 were replaced with silanized red phosphorus (Si-P), and the remaining raw materials, raw material dosages, and preparation steps were kept the same as those in Example 11, and finally a demagnetized flame-retardant composite material was obtained.

[0058] Example 13

[0059] A halogen-free low-smoke flame-retardant and demagnetized cable for ships includes a copper conductor. The copper conductor is made of stranded multi-strand oxygen-free copper wires (purity ≥ 99.99%). The copper conductor is treated by tin plating (tin layer thickness 5 μm) to improve corrosion resistance. An insulating layer is sleeved outside the copper conductor. The insulating layer is cross-linked polyethylene (XLPE) with a thickness of 1.5 mm and a density of 0.94 g / cm 3 , and the melt flow rate is 0.5 g / 10 min (190 °C / 2.16 kg). A demagnetized flame-retardant composite layer is sleeved outside the insulating layer. The thickness of the demagnetized flame-retardant composite layer is 2.2 mm, and the demagnetized flame-retardant composite layer is prepared from the demagnetized flame-retardant composite material prepared in Example 10.

[0060] Example 14

[0061] A halogen-free low-smoke flame-retardant and demagnetized cable for ships includes a copper conductor. The copper conductor is made of stranded multi-strand oxygen-free copper wires (purity ≥ 99.99%). The copper conductor is treated by tin plating (tin layer thickness 5 μm) to improve corrosion resistance. An insulating layer is sleeved outside the copper conductor. The insulating layer is cross-linked polyethylene (XLPE) with a thickness of 1.5 mm and a density of 0.94 g / cm 3 , and the melt flow rate is 0.5 g / 10 min (190 °C / 2.16 kg). A demagnetized flame-retardant composite layer is sleeved outside the insulating layer. The thickness of the demagnetized flame-retardant composite layer is 2.2 mm, and the demagnetized flame-retardant composite layer is prepared from the demagnetized flame-retardant composite material prepared in Example 11.

[0062] Example 15

[0063] A halogen-free low-smoke flame-retardant and demagnetized cable for ships includes a copper conductor. The copper conductor is made of stranded multi-strand oxygen-free copper wires (purity ≥ 99.99%). The copper conductor is treated by tin plating (tin layer thickness 5 μm) to improve corrosion resistance. An insulating layer is sleeved outside the copper conductor. The insulating layer is cross-linked polyethylene (XLPE) with a thickness of 1.5 mm and a density of 0.94 g / cm 3, the melt flow rate is 0.5 g / 10 min (190 °C / 2.16 kg). The outer layer of the insulating layer is provided with a demagnetizing and flame-retardant composite layer. The thickness of the demagnetizing and flame-retardant composite layer is 2.2 mm, and the demagnetizing and flame-retardant composite layer is prepared from the demagnetizing and flame-retardant composite material prepared in Example 12.

[0064] Comparative Example 6 Comparative Example 6 is the control group of Example 14. The demagnetizing and flame-retardant composite material prepared in Example 11 used in Example 14 is replaced with the flame-retardant composite material prepared in Comparative Example 1, and the rest of the structure remains the same as that in Example 14, and finally a cable is obtained.

[0065] Comparative Example 7 Comparative Example 7 is the control group of Example 14. The demagnetizing and flame-retardant composite material prepared in Example 11 used in Example 14 is replaced with the demagnetizing and flame-retardant composite material prepared in Comparative Example 2, and the rest of the structure remains the same as that in Example 14, and finally a cable is obtained.

[0066] Comparative Example 8 Comparative Example 8 is the control group of Example 14. The demagnetizing and flame-retardant composite material prepared in Example 11 used in Example 14 is replaced with the demagnetizing and flame-retardant composite material prepared in Comparative Example 3, and the rest of the structure remains the same as that in Example 14, and finally a cable is obtained.

[0067] Comparative Example 9 Comparative Example 9 is the control group of Example 14. The demagnetizing and flame-retardant composite material prepared in Example 11 used in Example 14 is replaced with the demagnetizing and flame-retardant composite material prepared in Comparative Example 4, and the rest of the structure remains the same as that in Example 14, and finally a cable is obtained.

[0068] Comparative Example 10 Comparative Example 10 is the control group of Example 14. The demagnetizing and flame-retardant composite material prepared in Example 11 used in Example 14 is replaced with the demagnetizing and flame-retardant composite material prepared in Comparative Example 5, and the rest of the structure remains the same as that in Example 14, and finally a cable is obtained.

[0069] Performance tests were carried out on the cables prepared in Examples 13 to 15 and Comparative Examples 6 to 10. The performance test process is as follows, and the test results are shown in Table 1: (1) Oxygen index (OI): Standard: GB / T2406.2 - 2009; Specimen size: 100 × 6.5 × 3 mm 3 ; Test conditions: Record the critical oxygen concentration for self-extinguishing after ignition.

[0070] (2) Smoke density (Ds): Standard: GB / T17651-2021; Equipment: Smoke density chamber (NBS type); Test conditions: The sample burns vertically, and the maximum specific optical density within 4 minutes after the flame goes out is recorded.

[0071] (3) Magnetic field decay rate: Standard: GJB1916-94; Equipment: Ring magnetic field generator (frequency 1 MHz, magnetic field strength 1 A / m); Calculation: MAR=(H0-H) / H0×100%, where H0 is the magnetic field strength before shielding and H is the strength after shielding.

[0072] (4) Tensile strength: Standard: ISO37:2017; Equipment: Universal material testing machine; Specimen size: Dumbbell shape (thickness 2 mm, gauge length 50 mm); Tensile rate: 50 mm / min.

[0073] Table 1 Test results Project Example 13 Example 14 Example 15 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Oxygen index (%) 47.5 48.3 48.8 34.2 31.5 35.7 38.4 40.1 Smoke density Ds 82.5 79.8 77.2 295.0 440.0 210.0 315.0 180.0 Magnetic field attenuation rate (%) 68.5 70.2 71.5 19.8 68.5 68.0 69.0 69.5 Tensile strength (MPa) 15.2 15.8 16.3 9.3 6.2 8.5 8.1 10.6 I. Comparative example settings and result analysis: (1) Comparative example 6 (deleting nano nickel-zinc ferrite): Magnetic field decay rate 19.8%: The loss of nano-ferrite leads to the loss of the demagnetization function, verifying its core role; Smoke density 295 Ds: Ferrite cannot inhibit the diffusion of soot during combustion, and the smoke suppression performance decreases by 72%; Oxygen index 34.2%: The flame retardant system is not directly affected, but it is still lower than that of the example (48%) because there is a synergistic effect between ferrite and flame retardant.

[0074] (2) Comparative example 7 (unmodified Al / Mg-OH): Oxygen index 31.5%: The low specific surface area of unmodified Al / Mg-OH results in a 34.8% decrease in flame retardant efficiency; Tensile strength 6.2 MPa: Poor interfacial bonding leads to deterioration of mechanical properties, which is 60.8% lower than that of example 14; Smoke density 440 Ds: Unmodified particles cannot form a dense carbon layer, and the smoke release amount surges by 452%.

[0075] (3) Comparative example 8 (only porous Al / Mg-OH): Oxygen index 35.7%: Phosphoric acid etching improves the specific surface area, but without silane coupling and MAH grafting, the flame retardant efficiency is still lower than that of the example (the difference is 26.3%); Smoke density 210 Ds: The porous structure partially inhibits smoke, but it is still higher than that of the example (79.8 Ds).

[0076] (4) Comparative example 9 (uncoated red phosphorus): Oxygen index 38.4%: It has a partial flame retardant effect but low efficiency; Smoke density 315 Ds: PH3 is released synergistically with smoke, and the smoke density increases by 295% compared with Example 14; Tensile strength 8.1 MPa: The interfacial bonding between red phosphorus and the matrix is poor, and the mechanical properties decrease by 48.7%.

[0077] (5) Comparative example 10 (only silanized red phosphorus): Oxygen index 40.1%: Silanization improves the dispersibility, but the release of PH3 is caused by the lack of MF coating, and the flame retardant efficiency is still lower than that of Example 14; Smoke density 180 Ds: The release amount of PH3 decreases, but it is still higher than that of the example (the difference is 125.3%).

[0078] II. Performance verification of the examples: Examples 13 - 15 (optimized scheme): Oxygen index ≥ 47.5%: The modified flame retardant (Al / Mg-OH@Si-MAH) and red phosphorus microcapsule (MCA-P) synergistically form a dense carbon layer, and the flame retardant efficiency is increased by more than 50% compared with the comparative example; Smoke density ≤ 82.5 Ds: The intercalated structure of nano-montmorillonite inhibits the diffusion of smoke and meets the IMO low-smoke standard (≤ 150 Ds); Magnetic field attenuation rate ≥ 68.5%: Nano-nickel-zinc ferrite (Ni 0.5 Zn 0.5 Fe2O4) is uniformly dispersed to form a magnetic loss network, meeting the requirements of GJB1916 for ship electromagnetic compatibility; Tensile strength ≥ 15.2 MPa: The dynamic cross-linking process (DCP-initiated EVA-MAH grafting) improves the interfacial binding energy, and the mechanical properties are better than those of traditional cables (6 - 8 MPa).

[0079] It should be noted that in this article, terms such as "including, containing" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0080] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill 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 present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A halogen-free, low-smoke, flame-retardant and degaussing cable for ships, characterized in that, It includes a copper conductor, an insulating layer is sleeved outside the copper conductor, and a demagnetizing and flame-retardant composite layer is sleeved outside the insulating layer; The demagnetizing and flame-retardant composite layer is prepared from a demagnetizing and flame-retardant composite material; The demagnetizing and flame-retardant composite material includes the following raw materials in parts by mass: 100 parts of ethylene-vinyl acetate copolymer, 15-20 parts of nano nickel-zinc ferrite, 60-80 parts of modified flame retardant, 10-15 parts of red phosphorus microcapsule, 3-5 parts of nano montmorillonite.

2. The halogen-free low-smoke flame-retardant and degaussing cable for ships according to claim 1, characterized in that, The nano nickel-zinc ferrite is prepared by the following steps: Dissolve Fe(NO3)3∙9H2O, Zn(NO3)2∙6H2O and Ni(NO3)2∙6H2O in deionized water, stir at room temperature for 30 min, then add citric acid monohydrate thereto, stir for 30 min, then dropwise add ammonia water to adjust the pH value of the solution to reach 4.0-4.2, then place it at 90-95 °C and stir until a dark green viscous wet sol is formed, then after room temperature aging and hot air drying, a dry gel is obtained, the dry gel is further heated to 400-420 °C and kept warm for 2-3 h, then heated to 1000-1050 °C and kept warm for 4-5 h, and then after cooling and grinding through a 100-mesh sieve, nano nickel-zinc ferrite is obtained.

3. The halogen-free low-smoke flame-retardant and degaussing cable for ships according to claim 2, wherein The dosage ratio of Fe(NO3)3∙9H2O, Zn(NO3)2∙6H2O, Ni(NO3)2∙6H2O, deionized water and citric acid monohydrate is 0.2 mol:0.05 mol:0.05 mol:800-1000 mL:0.45-0.50 mol.

4. A halogen-free low-smoke flame-retardant and degaussed cable for ships according to claim 1, characterized in that, The modified flame retardant is prepared by the following steps: A1. Mix Al(OH)3 and Mg(OH)2 in a mass ratio of 7:3, then add a 10% phosphoric acid solution thereto according to a solid-liquid ratio of 1:10, perform ultrasonic treatment at 60 °C for 1 hour, then mechanically stir at 60 °C for 2 hours. After completion, centrifuge and separate at 8000 rpm for 10 minutes, wash with deionized water until neutral, and vacuum dry at 80 °C for 6 hours to obtain porous Al / Mg-OH; A2. Disperse the porous Al / Mg-OH in absolute ethanol according to a solid-liquid ratio of 1:5, then add KH-570 accounting for 2%-5% of the mass of the porous Al / Mg-OH thereto, perform ultrasonic treatment at 60 °C for 30 minutes, then raise the temperature to 80 °C and mechanically stir and react for 3 hours. After completion, centrifuge and wash 3 times, and vacuum dry at 60 °C to obtain Al / Mg-OH@Si; A3. Premix Al / Mg-OH@Si, maleic anhydride and dicumyl peroxide, add them into a twin-screw extruder, with a screw speed of 200 rpm and a residence time of 5 minutes. After completion, extrude and pelletize, cool and then pass through a 40-mesh sieve to obtain the modified flame retardant.

5. A halogen-free, low-smoke, flame-retardant and degaussing cable for ships according to claim 4, characterized in that, The mass ratio of Al / Mg-OH@Si, maleic anhydride and dicumyl peroxide in A3 is 100:3:0.

5.

6. The halogen-free low-smoke flame-retardant and degaussing cable for ships according to claim 1, characterized in that, The red phosphorus microcapsule is prepared by the following steps: B1. Add red phosphorus powder and KH-570 into absolute ethanol, perform ultrasonic dispersion for 30 minutes, then under nitrogen protection, stir and react at 60 °C for 2 hours, then perform centrifugal separation, wash with ethanol 3 times, and vacuum dry at 80 °C for 6 hours to obtain silanized red phosphorus; B2. First, react melamine with 75% - 80% of the total amount of 37% formaldehyde solution at pH 8.5 and 65°C for 40 - 60 minutes to form a melamine - formaldehyde prepolymer. Then, add silanized red phosphorus to the above - mentioned melamine - formaldehyde prepolymer, and then add polyvinyl alcohol and nano - silica to it. Ultrasonically disperse for 20 minutes, then raise the temperature to 75 - 78°C, adjust the pH to 5.0 - 5.5, and carry out a constant - temperature stirring reaction for 1 hour. Then, add the remaining 37% formaldehyde solution, adjust the pH to 4.0 - 4.2, and react at 80 - 85°C for 1.5 hours. After completion, filter, wash with deionized water until neutral, and vacuum - dry at 60°C for 12 hours to obtain red - phosphorus microcapsules.

7. A halogen-free low-smoke flame-retardant and degaussing cable for ships according to claim 6, characterized in that, The mass ratio of the red - phosphorus powder, KH - 570, and absolute ethanol described in B1 is 100:3 - 4:

200.

8. A halogen-free low-smoke flame-retardant and degaussing cable for ships according to claim 6, characterized in that, The mass ratio of the melamine, 37% formaldehyde solution, silanized red phosphorus, polyvinyl alcohol, and nano - silica described in B1 is 15:40 - 50:50:2 - 3:

5.

9. The halogen-free low-smoke flame-retardant and degaussing cable for ships according to claim 1, characterized in that, The preparation process of the demagnetized flame - retardant composite material includes the following steps: Weigh the raw materials ethylene - vinyl acetate copolymer, nano - nickel zinc ferrite, modified flame - retardant, red - phosphorus microcapsules, and nano - montmorillonite according to mass parts. Then, add the ethylene - vinyl acetate copolymer, modified flame - retardant, red - phosphorus microcapsules, and nano - montmorillonite to a high - speed mixer for premixing for 10 minutes, then add nano - nickel zinc ferrite and diisopropylbenzene peroxide, and continue mixing for 5 minutes to obtain a mixture. Then, transfer the mixture to a solvent dispersion tank, add absolute ethanol according to a solid - to - liquid ratio of 1:3, ultrasonically treat for 20 minutes, and then carry out vacuum desolvation at 60°C to obtain a solid material. Place the solid material in a twin - screw extruder for melt co - extrusion, and then through granulation and annealing, obtain the demagnetized flame - retardant composite material.

10. A halogen-free low-smoke flame-retardant and degaussing cable for ships, characterized in that, The temperature gradient setting of the twin - screw extruder: melting section: 170 - 180°C, homogenizing section: 175°C, screw speed: 250 rpm, vacuum degree: - 0.08 MPa.