High-strength light weather-proof cable for unmanned aerial vehicle and preparation process of high-strength light weather-proof cable

Abstract

The invention relates to the technical field of cables, in particular to a high-strength light weather-proof cable for an unmanned aerial vehicle and a preparation process of the high-strength light weather-proof cable. According to the invention, the insulating layer, the aramid silicone grease sheath layer and the polyethylene sheath layer are sequentially coated outside the conductor, so that the finished high-strength light weather-proof cable for the unmanned aerial vehicle is obtained. The preparation process of the polyethylene sheath comprises the following steps: mixing linear low-density polyethylene, an irradiation cross-linking agent and flame-retardant POSS (Polyhedral Oligomeric Silsesquioxane), and pre-irradiating to obtain pre-treated polyethylene; and mixing the pretreated polyethylene, high-density polyethylene resin, polyolefin elastomer resin, weather-resistant modified carbon nanotubes and magnesium calcium carbonate, and carrying out high-temperature blending and extrusion molding to obtain the polyethylene sheath. The finished product prepared by the invention has excellent weather resistance and flame retardance, and also has high strength, bending resistance and electromagnetic interference resistance, thereby having wide application prospects in the technical field of cables.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cables, in particular to a high-strength lightweight weather-resistant cable for unmanned aerial vehicles and a preparation process thereof. BACKGROUND

[0002] As the main development of intelligent equipment for low-altitude economy, unmanned aerial vehicles are experiencing explosive development, and the cables for unmanned aerial vehicles also exhibit unique modern value in this process. From the performance guarantee level, the cable for unmanned aerial vehicles with a cross-linked polyethylene sheath is a key component to ensure the stable operation of the unmanned aerial vehicle. The cross-linked polyethylene sheath has good electrical insulation performance and mechanical performance, which can effectively protect the internal wires of the cable, so that the cable has high efficient power transmission capacity, stably transmits the power of the battery to each component, and ensures the normal operation of the power system and flight control system of the unmanned aerial vehicle. At the same time, under the protection of the good sheath, the cable also has excellent signal transmission performance to accurately transmit control instructions and sensor data, so that the unmanned aerial vehicle can accurately perform tasks.

[0003] However, during the execution of the task, the cable continuously transmits power and signals. Once the cable generates high temperature or open flame due to short circuit, overload, etc., it is easy to cause safety accidents. Therefore, it is necessary to prepare a cable with good flame retardant performance, so as to effectively prevent the spread of fire and avoid causing greater safety accidents. Moreover, during the flight of the unmanned aerial vehicle, the cable is exposed to various environments, and the oxygen in the air will chemically react with the material of the cable, causing the cable material to age. If the insulation layer of the cable is oxidized, the insulation performance will decrease, which may cause problems such as electric leakage and short circuit, seriously affecting the normal operation of the unmanned aerial vehicle. Improving the anti-oxidation weather resistance of the cable can slow down the oxidation speed of the cable material, prolong the service life of the cable, and reduce the frequency and cost of replacing the cable.

[0004] In order to overcome the defects of the prior art, the present application provides a high-strength lightweight weather-resistant cable for unmanned aerial vehicles and a preparation process thereof. SUMMARY

[0005] The purpose of the present application is to provide a high-strength lightweight weather-resistant cable for unmanned aerial vehicles and a preparation process thereof to solve the problems in the prior art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: A high-strength lightweight weather-resistant cable for unmanned aerial vehicles, comprising a conductor, an insulation layer, an aramid silicone grease sheath layer, and a polyethylene sheath layer; the insulation layer is a skin-bubble-skin carbon-based coating lightweight insulation, which comprises an inner skin layer, an intermediate layer, and an outer skin layer from inside to outside.

[0007] More preferably, the conductor is a light-weight high-strength conductor, and the structure is a composite stranded wire of 0.02-0.04 mm extremely thin silver-plated copper clad aluminum alloy wire and carbon fiber; the inner skin layer material is ethylene-tetrafluoroethylene copolymer with a thickness of 0.05-0.2 mm; the intermediate layer is foamed ethylene-tetrafluoroethylene copolymer with a foaming degree of 40-60%; the outer skin layer is a semi-conductive nano-graphite coating; and the aramid silicone grease sheath layer is a mixture of aramid and silicone grease.

[0008] More preferably, the conductor has excellent tensile strength and bending resistance, and can withstand 300 million small-radius bends.

[0009] More preferably, the inner skin layer ethylene-tetrafluoroethylene copolymer is a kind of Teflon plastic, which has the advantages of chemical corrosion resistance, high and low temperature resistance, and small density.

[0010] More preferably, the foamed structure of the intermediate layer can effectively reduce the density and dielectric constant of the material, reduce the weight of the cable and improve the signal transmission performance of the cable.

[0011] More preferably, the foaming degree of the foamed structure of the intermediate layer is 40-60%; the foaming process adopts physical foaming, and the foaming source is high-purity nitrogen, and the foaming rate is controlled by controlling the injection amount of nitrogen.

[0012] More preferably, the formation process of the semi-conductive nano-graphite coating of the outer skin layer is: dispersing graphite nanoparticles in a solvent, then adding a tackifier and an additive to form a stable sol; coating the sol on the surface of the substrate, and curing at 500 DEG C for 3-5 s to form a semi-conductive nano-graphite coating; the coating thickness is 0.03-0.08 mm.

[0013] More preferably, the sol coating process is to form uniform micron-sized droplets by an atomizing nozzle, and then adhere the droplets to the surface of the substrate.

[0014] More preferably, the solvent is a polar solution formed by mixing cetyltrimethylammonium bromide and polyvinylpyrrolidone.

[0015] More preferably, the tackifier is graphene or a derivative of graphene, specifically graphene oxide or functionalized graphene; the present application uses graphene oxide as a tackifier, which is suitable for polar systems.

[0016] More preferably, when the addition ratio of graphene oxide is 1.5%, the strength of the graphene oxide modified cable is optimal at 30.1 MPa; when the addition ratio of graphene oxide exceeds 1.5%, graphene oxide tends to agglomerate, resulting in a decrease in strength.

[0017] More preferably, the semi-conductive graphite coating has the characteristics of light weight, toughness, low cost and corrosion resistance; the semi-conductive graphite coating can also effectively improve the anti-electromagnetic interference capability of the cable.

[0018] More preferably, aramid has the advantages of high strength, high modulus and high temperature resistance, and using aramid as a sheath material can effectively improve the cable's tensile strength.

[0019] More preferably, the formation process of the aramid silicone grease sheath layer is as follows: spraying silicone grease on the outside of aramid, sintering and curing to obtain an aramid silicone grease sheath layer; according to different requirements of tensile strength, different specifications of aramid fiber (100D-30000D) are selected to weave the cable sheath layer.

[0020] More preferably, the preparation process of the polyethylene sheath layer is as follows: mixing linear low-density polyethylene, irradiation crosslinking agent and flame-retardant POSS uniformly, pre-irradiation treatment to obtain pretreated polyethylene; mixing the pretreated polyethylene, high-density polyethylene resin, polyolefin elastomer resin, weather-resistant modified carbon nanotube and magnesium calcium carbonate, blending and stirring at 150-180℃ for 8-10min, and extruding to form a polyethylene sheath with a thickness of 1.0-1.2mm.

[0021] More preferably, the content of each component of the polyethylene sheath is as follows: 20-25 parts of linear low-density polyethylene, 0.2-0.3 parts of irradiation crosslinking agent, 2-3 parts of high-density polyethylene resin, 3-5 parts of polyolefin elastomer resin, 4-5 parts of flame-retardant POSS, 0.25-0.30 parts of weather-resistant modified carbon nanotube, and 20-25 parts of magnesium calcium carbonate, all by mass fraction; the irradiation crosslinking agent is triallyl isocyanurate.

[0022] More preferably, the pre-irradiation treatment parameters are as follows: the transmission speed is 0.08-0.09m / s, and the pre-irradiation dose is 18-20kGy.

[0023] More preferably, the preparation process of the weather-resistant modified carbon nanotube is as follows: Step S1: adding thionyl chloride to dimethyl sulfoxide and stirring uniformly to obtain a thionyl chloride solution; adding the thionyl chloride solution and methacrylic acid to tetrahydrofuran, stirring uniformly, then adding N,N-dimethylformamide, and reacting at 60-65℃ for 4-5h, then distilling under reduced pressure to obtain methacryloyl chloride; Step S2: under a nitrogen environment, adding 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid to anhydrous dichloromethane, stirring uniformly, then adding thionyl chloride, refluxing at 40-45℃ for 8-10h, and then distilling under reduced pressure to obtain a chlorinated antioxidant; Step S3: adding the hydroxylated carbon nanotube into anhydrous toluene, uniformly dispersing under ultrasonic, adding 3-aminopropyl triethoxysilane, stirring uniformly, adding deionized water, stirring and reacting at 65-70 DEG C for 25-30h, after the reaction is completed, filtering, extracting and drying to obtain the aminated carbon nanotube; adding methyl acryloyl chloride, chlorinated antioxidant and hexachlorocyclotriphosphazene into anhydrous toluene, uniformly dispersing under ultrasonic, adding into the anhydrous toluene dispersion of the aminated carbon nanotube, stirring uniformly, adding triethylamine dropwise, reacting at 75-80 DEG C for 20-30h, after the reaction is completed, filtering, washing and drying to obtain the weather-resistant modified carbon nanotube.

[0024] More preferably, the reaction molar ratio of chlorosulfoxide and methacrylic acid is 1: (1.0-1.1); the reaction mass ratio of 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid and chlorosulfoxide is (0.35-0.36):1.5; the reaction mass ratio of hydroxylated carbon nanotube and 3-aminopropyl triethoxysilane is 0.4:(1.6-1.8); the reaction mass ratio of methyl acryloyl chloride, chlorinated antioxidant, hexachlorocyclotriphosphazene and aminated carbon nanotube is 0.7:(0.2-0.3):(0.8-1.0):0.25.

[0025] More preferably, the preparation process of the flame-retardant POSS is as follows: Step S1: adding triallyl cyanurate and azobisisobutyronitrile into ethyl acetate to obtain a triallyl cyanurate reaction solution; under a nitrogen environment, adding 2,2'-(1,2-ethylenediyl bisoxo) bisethyl mercaptan into ethyl acetate, stirring and dissolving, heating to 70-75 DEG C, then slowly adding the triallyl cyanurate reaction solution, continuing to react for 20-25h after the addition is completed, after the reaction is completed, filtering, rotary evaporation, washing and drying to obtain the terminal mercapto flame retardant; Step S2: adding vinyl POSS and the terminal mercapto flame retardant into toluene, stirring uniformly, purifying by bubbling for 30-40min, then adding azobisisobutyronitrile, continuing to bubble and stir for 10-15min, after the stirring is completed, reacting at 80-90 DEG C for 6-7h, after the reaction is completed, rotary evaporation, vacuum drying to obtain the flame-retardant POSS.

[0026] More preferably, the reaction molar ratio of triallyl cyanurate and 2,2'-(1,2-ethylenediyl bisoxo) bisethyl mercaptan is 1:(3.1-3.2); the reaction molar ratio of vinyl POSS and the terminal mercapto flame retardant is 1:(4.5-5.0).

[0027] The beneficial effects of the present application are as follows: The application is characterized in that linear low-density polyethylene, a radiation crosslinking agent, and flame-retardant POSS are mixed to obtain pretreated polyethylene through pre-irradiation; the pretreated polyethylene, high-density polyethylene resin, polyolefin elastomer resin, weather-resistant modified carbon nanotubes, and magnesium calcium carbonate are mixed to obtain a polyethylene sheath through high-temperature blending and extrusion molding.

[0028] The application is characterized in that, in the preparation process of the weather-resistant modified carbon nanotubes, the chlorinated antioxidant is prepared by chlorination reaction of 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid and chlorosulfoxide. 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid is a common hindered phenolic antioxidant. The phenolic hydroxyl group in the molecule has a reactive hydrogen atom, which can react with free radicals to terminate the free radical chain reaction, thereby inhibiting the oxidation process. Through substitution reaction with the amino-functionalized carbon nanotubes, this antioxidant group is introduced to the surface of the carbon nanotubes. When these weather-resistant modified carbon nanotubes are dispersed in the polyethylene sheath, the antioxidant group can capture free radicals generated in the oxidation process, prevent the oxidative degradation of the polyethylene molecular chain, and improve the antioxidant performance of the sheath. In addition, the carbon nanotubes themselves have good chemical stability and mechanical properties. They form a conductive network in the polyethylene matrix, not only improving the physical properties of the material, but also to some extent dispersing stress and reducing micro-defects caused by external environmental factors (such as light, oxygen, etc.), thereby reducing the contact opportunities of the polyethylene molecular chain with oxygen and further enhancing the antioxidant effect.

[0029] The application is characterized in that, in the preparation process of the flame-retardant POSS, triallyl cyanurate contains nitrogen elements, and 2,2'-(1,2-ethanediyldioxy) bisethanethiol contains sulfur elements, which have flame-retardant effects in the combustion process. Through thiol-ene click reaction, these groups containing flame-retardant elements are introduced into the vinyl POSS. POSS (polyhedral oligomeric silsesquioxane) has a unique cage-like structure, and silicon itself also has good flame-retardant properties. When the polyethylene sheath burns, the nitrogen, sulfur, and silicon elements in the flame-retardant POSS can form a dense carbon layer on the surface of the material, which can block the transmission of oxygen and heat and inhibit the continuation of combustion. In addition, the phosphorus-containing group in the weather-resistant modified carbon nanotubes (from hexachlorocyclotriphosphazene) can promote carbonization and form a carbon layer when burning, which synergistically acts with the flame-retardant POSS to improve the flame-retardant effect. At the same time, magnesium calcium carbonate will decompose and absorb heat at high temperatures, reducing the temperature of the material surface, which also helps to inhibit combustion.

[0030] The application is characterized in that methyl methacryloyl chloride, chlorinated antioxidant, hexachlorocyclotriphosphazene and aminated carbon nanotubes are mixed to generate a substitution reaction to obtain a weather-resistant modified carbon nanotube.

[0031] The preparation process of the flame-retardant POSS is as follows: by adding triallyl cyanurate, azobisisobutyronitrile and 2,2'-(1,2-ethylenedioxy) bisethyl mercaptan, a mercapto-alkene click reaction is generated to obtain a terminal mercapto flame retardant; then the terminal mercapto flame retardant and vinyl POSS are mixed to continue the mercapto-alkene click reaction, by setting the reaction molar ratio of vinyl POSS and terminal mercapto flame retardant to 1:(4.5-5.0), the flame-retardant POSS is obtained, which introduces a flame-retardant structure and also retains part of the carbon-carbon double bond, so that the flame-retardant POSS can be effectively crosslinked and blended with the raw materials in the polyolefin resin.

[0032] The cable product prepared by the application comprises a conductor, an insulating layer, an aramid silicone sheath layer and a polyethylene sheath layer; the insulating layer is a skin-bubble-skin carbon-based coating lightweight insulation, and from the inside to the outside, it comprises an inner skin layer, an intermediate layer and an outer skin layer. (1) The cable has high strength and can meet various complex working scenarios of the unmanned aerial vehicle during flight; (2) The conductor of the cable adopts a composite stranded wire of extremely fine silver-plated copper clad aluminum alloy wire and carbon fiber, so that the cable has excellent bending resistance, which effectively guarantees the efficient work of the unmanned aerial vehicle; (3) The insulating material of the cable adopts a skin-bubble-skin carbon-based coating lightweight insulation, which effectively improves the anti-electromagnetic interference ability and signal transmission ability of the cable; this advantage can guarantee the long-distance work of the unmanned aerial vehicle.

[0033] (4) The outer sheath adopts aramid silicone material, which solves the winding and unwinding problem of the traditional cable.

[0034] In summary, the finished product prepared by the application has excellent weather resistance and flame retardance, and also has high strength, bending resistance and anti-electromagnetic interference performance, so it has a wide application prospect in the field of cable technology. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 The figure is a structural schematic diagram of the application. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the protection scope of the present application.

[0037] Raw material sources: Hydroxylated carbon nanotubes, provided by Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, with a hydroxyl content of 5.6wt% and an outer diameter of 10nm; vinyl POSS, provided by Hubei Xingyan New Material Technology Co., Ltd., with a molecular weight of 633; linear low-density polyethylene, provided by China Petroleum Natural Gas Co., Ltd., with a specification of DFDA-7024; high-density polyethylene resin, provided by Shanghai Hongchao Plastic Raw Material Co., Ltd., with a density of 0.962g / cm 3 ; polyolefin elastomer resin, provided by Suzhou Cirene Plastic Co., Ltd., with a model number of 8401; magnesium calcium carbonate, provided by Lingshu County Shuangshi Mineral Product Processing Factory, with a mesh of 325; ethylene-tetrafluoroethylene copolymer, provided by Dongguan Wan Shi Xin Plastic Raw Material Co., Ltd., with a model number of 750; in mass parts, one part is 1g.

[0038] Example 1: Step S1: add sulfur chloride to dimethyl sulfoxide and stir to obtain a sulfur chloride solution; add the sulfur chloride solution and methacrylic acid to tetrahydrofuran, stir uniformly, then add N,N-dimethylformamide, and react at 65℃ for 5h; after the reaction is completed, distill under reduced pressure to obtain methacryloyl chloride; the reaction molar ratio of sulfur chloride to methacrylic acid is 1:1.05; Step S2: under a nitrogen environment, add 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid to anhydrous dichloromethane, stir uniformly, then add sulfur chloride, and reflux at 45℃ for 10h; after the reaction is completed, distill under reduced pressure to obtain chlorinated antioxidant; the reaction mass ratio of 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid to sulfur chloride is 0.355:1.5; Step S3: add the hydroxylated carbon nanotubes to anhydrous toluene, uniformly disperse by ultrasonic, then add 3-aminopropyl triethoxysilane, uniformly stir, then add deionized water, stir at 70 DEG C for 30 hours, after the reaction is completed, filter, extract and dry to obtain the aminated carbon nanotubes; add methacryloyl chloride, chlorinated antioxidant and hexachlorotriphosphazene to anhydrous toluene, uniformly disperse by ultrasonic, then add to the anhydrous toluene dispersion of the aminated carbon nanotubes, uniformly stir, then drop 3 drops of triethylamine, react at 80 DEG C for 30 hours, after the reaction is completed, filter, wash and dry to obtain the weather-resistant modified carbon nanotubes; the reaction mass ratio of the hydroxylated carbon nanotubes and 3-aminopropyl triethoxysilane is 0.4:1.7; the reaction mass ratio of the methacryloyl chloride, chlorinated antioxidant, hexachlorotriphosphazene and aminated carbon nanotubes is 0.7:0.25:0.9:0.25; Step S4: add triallyl cyanurate and azobisisobutyronitrile to ethyl acetate, uniformly stir to obtain a triallyl cyanurate reaction solution; under a nitrogen environment, add 2,2'-(1,2-ethylenedioxy) bisethyl mercaptan to ethyl acetate, stir to dissolve, then heat to 75 DEG C, slowly drop the triallyl cyanurate reaction solution, after the dropping is completed, continue to react for 25 hours, after the reaction is completed, filter, rotary evaporate, wash and dry to obtain the terminal mercapto flame retardant; the reaction molar ratio of the triallyl cyanurate and 2,2'-(1,2-ethylenedioxy) bisethyl mercaptan is 1:3.15; Step S5: add vinyl POSS and terminal mercapto flame retardant to toluene, uniformly stir, then bubble purify for 40 minutes, then add azobisisobutyronitrile, continue to bubble and stir for 15 minutes, after the stirring is completed, react at 90 DEG C for 7 hours, after the reaction is completed, rotary evaporate and vacuum dry to obtain the flame-retardant POSS; the reaction molar ratio of the vinyl POSS and terminal mercapto flame retardant is 1:4.8; Step S6: uniformly mix 20g of linear low-density polyethylene, 0.2g of triallyl isocyanurate and 4g of flame-retardant POSS, and pre-irradiate to obtain pre-irradiated polyethylene; mix the pre-irradiated polyethylene, 2g of high-density polyethylene resin, 3g of polyolefin elastomer resin, 0.25g of weather-resistant modified carbon nanotubes and 20g of calcium magnesium carbonate, and blend and stir at 180 DEG C for 10 minutes, and extrude to form a polyethylene sheath with a thickness of 1.0mm; the pre-irradiation treatment parameters are: a transmission speed of 0.09m / s and a pre-irradiation dose of 20kGy; Step S7: sequentially coat an insulating layer, an aramid silicone grease sheath layer and a polyethylene sheath layer outside the conductor to obtain a finished product; the insulating layer is a skin-cell-skin carbon-based coating lightweight insulation, and from the inside to the outside, it is an inner skin layer, a middle layer and an outer skin layer; The conductor is a light-weight high-strength conductor, and the structure is a composite stranded wire of 0.04 mm extremely thin silver-plated copper-clad aluminum alloy wire and carbon fiber; the inner sheath material is ethylene-tetrafluoroethylene copolymer, and the thickness is 0.05 mm; the middle layer is foamed ethylene-tetrafluoroethylene copolymer, and the foaming degree is 42%; the outer sheath is a semi-conductive nano-graphite coating; the composition of the aramid silicone grease sheath layer is a mixture of aramid and silicone grease; the formation process of the semi-conductive nano-graphite coating is: dispersing graphite nanoparticles in a solvent, then adding a binder and an additive to form a stable sol; coating the sol on the surface of the substrate, curing at 500 DEG C for 4 s to form a semi-conductive nano-graphite coating; the coating thickness is 0.035 mm.

[0039] Example 2: Step S1: add thionyl chloride to dimethyl sulfoxide and stir to obtain a thionyl chloride solution; add the thionyl chloride solution and methacrylic acid to tetrahydrofuran, stir uniformly, then add N,N-dimethylformamide, and react at 62 DEG C for 4.5 h; after the reaction is completed, distill under reduced pressure to obtain methacryloyl chloride; the reaction molar ratio of thionyl chloride to methacrylic acid is 1:1.05; Step S2: under a nitrogen environment, add 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid to anhydrous dichloromethane, stir uniformly, then add thionyl chloride, and reflux at 42 DEG C for 9 h; after the reaction is completed, distill under reduced pressure to obtain a chlorinated antioxidant; the reaction mass ratio of 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid to thionyl chloride is 0.355:1.5; Step S3: add hydroxylated carbon nanotubes to anhydrous toluene, ultrasonically disperse uniformly, then add 3-aminopropyl triethoxysilane, stir uniformly, then add deionized water, and stir and react at 67 DEG C for 27 h; after the reaction is completed, filter, extract, and dry to obtain aminated carbon nanotubes; add methacryloyl chloride, chlorinated antioxidant, and hexachlorotriphosphazene to anhydrous toluene, ultrasonically disperse uniformly, then add to the anhydrous toluene dispersion of aminated carbon nanotubes, stir uniformly, then dropwise add triethylamine, and react at 77 DEG C for 25 h; after the reaction is completed, perform suction filtration, washing, and drying to obtain weather-resistant modified carbon nanotubes; the reaction mass ratio of hydroxylated carbon nanotubes to 3-aminopropyl triethoxysilane is 0.4:1.7; the reaction mass ratio of methacryloyl chloride, chlorinated antioxidant, hexachlorotriphosphazene, and aminated carbon nanotubes is 0.7:0.25:0.9:0.25; Step S4: Add allyl cyanate and azobisisobutyronitrile to ethyl acetate and stir until homogeneous to obtain an allyl cyanate reaction solution; under nitrogen atmosphere, add 2,2'-(1,2-ethylenedioxy)diethylthiol to ethyl acetate, stir to dissolve, heat to 72°C, and then slowly add the allyl cyanate reaction solution dropwise. After the addition is complete, continue the reaction for 22 hours. After the reaction is complete, filter, rotary evaporate, wash, and dry to obtain a mercapto-terminated flame retardant; the molar ratio of allyl cyanate to 2,2'-(1,2-ethylenedioxy)diethylthiol is 1:3.15. Step S5: Add vinyl POSS and mercapto-terminated flame retardant to toluene, stir evenly, and purify by bubbling for 35 min. Then add azobisisobutyronitrile and continue bubbling and stirring for 12 min. After stirring, react at 85℃ for 6.5 h. After the reaction, evaporate by rotary evaporation and vacuum dry to obtain flame retardant POSS. The molar ratio of vinyl POSS to mercapto-terminated flame retardant is 1:4.8. Step S6: Mix 20g of linear low-density polyethylene, 0.2g of triallyl isocyanate, and 4g of flame-retardant POSS evenly, and pre-irradiate to obtain pre-treated polyethylene; mix the pre-treated polyethylene, 2g of high-density polyethylene resin, 3g of polyolefin elastomer resin, 0.25g of weather-resistant modified carbon nanotubes, and 20g of magnesium calcium carbonate, stir at 165℃ for 9min, and extrude to obtain a polyethylene sheath with a thickness of 1.0mm; pre-irradiation treatment parameters: transfer velocity is 0.085m / s, pre-irradiation dose is 19kGy; Step S7: The insulation layer, aramid silicone grease sheath layer, and polyethylene sheath layer are sequentially wrapped around the outside of the conductor to obtain the finished product; the insulation layer is a skin-foam-skin carbon-based coating lightweight insulation, which consists of an inner skin layer, an intermediate layer, and an outer skin layer from the inside out; The conductor is a lightweight, high-strength conductor, with a structure consisting of a composite strand of 0.04mm ultra-fine silver-plated copper-clad aluminum alloy wire and carbon fiber; the inner sheath material is ethylene-tetrafluoroethylene copolymer with a thickness of 0.05mm; the middle layer is foamed ethylene-tetrafluoroethylene copolymer with a foaming degree of 42%; the outer sheath is a semi-conductive nano-graphite coating; the aramid silicone grease sheath layer is composed of a mixture of aramid and silicone grease; the formation process of the semi-conductive nano-graphite coating is as follows: graphite nanoparticles are dispersed in a solvent, and then binders and additives are added to form a stable sol; the sol is coated on the surface of the substrate and cured at 500℃ for 4s to form a semi-conductive nano-graphite coating; the coating thickness is 0.035mm.

[0040] Example 3: Step S1: Add thionyl chloride to dimethyl sulfoxide and stir until homogeneous to obtain a thionyl chloride solution; add the thionyl chloride solution and methacrylic acid to tetrahydrofuran, stir until homogeneous, then add N,N-dimethylformamide and react at 60°C for 4 hours. After the reaction is completed, distill under reduced pressure to obtain methacryloyl chloride; the molar ratio of thionyl chloride to methacrylic acid is 1:1.05. Step S2: Under nitrogen atmosphere, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid was added to anhydrous dichloromethane, stirred until homogeneous, and then thionyl chloride was added. The mixture was refluxed at 40°C for 8 hours. After the reaction was completed, the chlorinated antioxidant was obtained by vacuum distillation. The mass ratio of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid to thionyl chloride was 0.355:1.5. Step S3: Hydroxylated carbon nanotubes were added to anhydrous toluene and ultrasonically dispersed. 3-Aminopropyltriethoxysilane was then added, stirred until homogeneous, and deionized water was added. The mixture was stirred at 65°C for 25 hours. After the reaction, the mixture was filtered, extracted, and dried to obtain aminolated carbon nanotubes. Methacrylamide chloride, chlorinated antioxidant, and hexachlorocyclotriphosphazene were added to anhydrous toluene and ultrasonically dispersed. This mixture was then added to the anhydrous toluene dispersion of aminolated carbon nanotubes. After stirring until homogeneous, triethylamine was added dropwise. The mixture was reacted at 75°C for 20 hours. After the reaction, the mixture was filtered, washed, and dried to obtain weather-resistant modified carbon nanotubes. The mass ratio of hydroxylated carbon nanotubes to 3-aminopropyltriethoxysilane was 0.4:1.7; the mass ratio of methacryloylamide chloride, chlorinated antioxidant, hexachlorocyclotriphosphazene, and aminolated carbon nanotubes was 0.7:0.25:0.9:0.25. Step S4: Add allyl cyanate and azobisisobutyronitrile to ethyl acetate and stir until homogeneous to obtain an allyl cyanate reaction solution; under nitrogen atmosphere, add 2,2'-(1,2-ethylenedioxy)diethylthiol to ethyl acetate, stir to dissolve, heat to 70°C, and then slowly add the allyl cyanate reaction solution dropwise. After the addition is complete, continue the reaction for 20 hours. After the reaction is complete, filter, rotary evaporate, wash, and dry to obtain a mercapto-terminated flame retardant; the molar ratio of allyl cyanate to 2,2'-(1,2-ethylenedioxy)diethylthiol is 1:3.15. Step S5: Add vinyl POSS and mercapto-terminated flame retardant to toluene, stir evenly, and purify by bubbling for 30 min. Then add azobisisobutyronitrile and continue bubbling and stirring for 10 min. After stirring, react at 80℃ for 6 h. After the reaction, evaporate by rotary evaporation and vacuum dry to obtain flame retardant POSS. The molar ratio of vinyl POSS to mercapto-terminated flame retardant is 1:4.8. Step S6: Mix 20g of linear low-density polyethylene, 0.2g of triallyl isocyanate, and 4g of flame-retardant POSS evenly, and pre-irradiate to obtain pretreated polyethylene; mix the pretreated polyethylene, 2g of high-density polyethylene resin, 3g of polyolefin elastomer resin, 0.25g of weather-resistant modified carbon nanotubes, and 20g of magnesium calcium carbonate, stir at 150℃ for 8min, and extrude to obtain a polyethylene sheath with a thickness of 1.0mm; pre-irradiation treatment parameters: transfer velocity is 0.08m / s, pre-irradiation dose is 18kGy; Step S7: The insulation layer, aramid silicone grease sheath layer, and polyethylene sheath layer are sequentially wrapped around the outside of the conductor to obtain the finished product; the insulation layer is a skin-foam-skin carbon-based coating lightweight insulation, which consists of an inner skin layer, an intermediate layer, and an outer skin layer from the inside out; The conductor is a lightweight, high-strength conductor, with a structure consisting of a composite strand of 0.04mm ultra-fine silver-plated copper-clad aluminum alloy wire and carbon fiber; the inner sheath material is ethylene-tetrafluoroethylene copolymer with a thickness of 0.05mm; the middle layer is foamed ethylene-tetrafluoroethylene copolymer with a foaming degree of 42%; the outer sheath is a semi-conductive nano-graphite coating; the aramid silicone grease sheath layer is composed of a mixture of aramid and silicone grease; the formation process of the semi-conductive nano-graphite coating is as follows: graphite nanoparticles are dispersed in a solvent, and then binders and additives are added to form a stable sol; the sol is coated on the surface of the substrate and cured at 500℃ for 4s to form a semi-conductive nano-graphite coating; the coating thickness is 0.035mm.

[0041] Comparative Example 1: The weather-resistant modified carbon nanotubes were removed, and the rest was the same as in Example 1. The specific steps are as follows: Step S1: Triallyl cyanurate and azobisisobutyronitrile were added to ethyl acetate and stirred until homogeneous to obtain a cyanallyl cyanurate reaction solution; under nitrogen atmosphere, 2,2'-(1,2-ethylenedioxy)diethylthiol was added to ethyl acetate, stirred until dissolved, heated to 75°C, and then the cyanallyl cyanurate reaction solution was slowly added dropwise. After the addition was completed, the reaction was continued for 25 hours. After the reaction was completed, the mixture was filtered, rotary evaporated, washed, and dried to obtain a mercapto-terminated flame retardant; the molar ratio of cyanallyl cyanurate to 2,2'-(1,2-ethylenedioxy)diethylthiol was 1:3.15. Step S2: Add vinyl POSS and mercapto-terminated flame retardant to toluene, stir evenly, and purify by bubbling for 40 min. Then add azobisisobutyronitrile and continue bubbling and stirring for 15 min. After stirring, react at 90℃ for 7 h. After the reaction, evaporate by rotary evaporation and vacuum dry to obtain flame retardant POSS. The molar ratio of vinyl POSS to mercapto-terminated flame retardant is 1:4.8. Step S3: Mix 20g of linear low-density polyethylene, 0.2g of triallyl isocyanate, and 4g of flame-retardant POSS evenly, and pre-irradiate to obtain pretreated polyethylene; mix the pretreated polyethylene, 2g of high-density polyethylene resin, 3g of polyolefin elastomer resin, and 20g of magnesium calcium carbonate, stir at 180℃ for 10min, and extrude to obtain a polyethylene sheath with a thickness of 1.0mm; pre-irradiation parameters: transfer speed is 0.09m / s, pre-irradiation dose is 20kGy; Step S4: The insulation layer, aramid silicone grease sheath layer, and polyethylene sheath layer are sequentially wrapped around the outside of the conductor to obtain the finished product; the insulation layer is a lightweight insulation with a skin-foam-skin carbon-based coating, consisting of an inner skin layer, an intermediate layer, and an outer skin layer from the inside out; The conductor is a lightweight, high-strength conductor, with a structure consisting of a composite strand of 0.04mm ultra-fine silver-plated copper-clad aluminum alloy wire and carbon fiber; the inner sheath material is ethylene-tetrafluoroethylene copolymer with a thickness of 0.05mm; the middle layer is foamed ethylene-tetrafluoroethylene copolymer with a foaming degree of 42%; the outer sheath is a semi-conductive nano-graphite coating; the aramid silicone grease sheath layer is composed of a mixture of aramid and silicone grease; the formation process of the semi-conductive nano-graphite coating is as follows: graphite nanoparticles are dispersed in a solvent, and then binders and additives are added to form a stable sol; the sol is coated on the surface of the substrate and cured at 500℃ for 4s to form a semi-conductive nano-graphite coating; the coating thickness is 0.035mm.

[0042] Comparative Example 2: Weather-resistant modified carbon nanotubes and flame-retardant POSS were removed, and the rest was the same as in Example 1. The specific steps are as follows: Step S1: 20g of linear low-density polyethylene and 0.2g of triallyl isocyanate were mixed evenly and pre-irradiated to obtain pre-treated polyethylene; the pre-treated polyethylene, 2g of high-density polyethylene resin, 3g of polyolefin elastomer resin and 20g of magnesium calcium carbonate were mixed and stirred at 180℃ for 10min and extruded to obtain a polyethylene sheath with a thickness of 1.0mm; the pre-irradiation treatment parameters were: transfer speed of 0.09m / s and pre-irradiation dose of 20kGy. Step S2: The insulation layer, aramid silicone grease sheath layer, and polyethylene sheath layer are sequentially wrapped around the outside of the conductor to obtain the finished product; the insulation layer is a lightweight insulation with a skin-foam-skin carbon-based coating, consisting of an inner skin layer, an intermediate layer, and an outer skin layer from the inside out; The conductor is a lightweight, high-strength conductor, with a structure consisting of a composite strand of 0.04mm ultra-fine silver-plated copper-clad aluminum alloy wire and carbon fiber; the inner sheath material is ethylene-tetrafluoroethylene copolymer with a thickness of 0.05mm; the middle layer is foamed ethylene-tetrafluoroethylene copolymer with a foaming degree of 42%; the outer sheath is a semi-conductive nano-graphite coating; the aramid silicone grease sheath layer is composed of a mixture of aramid and silicone grease; the formation process of the semi-conductive nano-graphite coating is as follows: graphite nanoparticles are dispersed in a solvent, and then binders and additives are added to form a stable sol; the sol is coated on the surface of the substrate and cured at 500℃ for 4s to form a semi-conductive nano-graphite coating; the coating thickness is 0.035mm.

[0043] Testing and experimentation: Flame retardancy test: Referring to GB / T 2406.2-2022 "Determination of burning behavior of plastics by oxygen index method - Part 2: Room temperature test", the polyethylene sheath prepared by this invention was cut into long strips, and the oxygen index value was tested and recorded.

[0044] Vertical burning test: The polyethylene sheath prepared in this invention was cut into 130×13mm specimens, and the flame retardancy rating of the specimens was determined using the FFT008 instrument in accordance with ASTM D 3801.

[0045] Antioxidant resistance test: The polyethylene sheath prepared according to this invention was immersed in an aqueous solution with a chlorine content of 5 mg / L for 15 days to obtain a pretreated polyethylene sheath. The oxidation induction period was tested according to GB / T 19466.6-2009 at a test temperature of 250℃. The results are shown in the table below: Oxygen index / % Flame class Oxidation induction time / min Example 1 31.6 V-0 185 Example 2 31.4 V-0 183 Example 3 31.3 V-0 182 Comparative Example 1 27.5 V-0 137 Comparative Example 2 23.3 V-1 129 Conclusion: In Examples 1-3, the dosage remained unchanged, with only some reaction parameters modified. Experimental data showed no significant fluctuations in the performance of the samples.

[0046] Comparative Example 1: The weather-resistant modified carbon nanotubes were removed, while the rest remained the same as in Example 1. Experimental data showed that, compared to Example 1, the oxygen index decreased to 27.5%, and the oxidation induction period shortened to 137 min. The reason for this is that the weather-resistant modified carbon nanotubes contain phosphorus-containing groups, which synergistically enhance the flame-retardant effect with the flame-retardant POSS. Therefore, removing them reduced the oxygen index. Furthermore, hindered phenols were introduced onto the surface of the weather-resistant modified carbon nanotubes; therefore, removing them shortened the oxidation induction period.

[0047] Comparative Example 2: Weather-resistant modified carbon nanotubes and flame-retardant POSS were removed, while the rest remained the same as in Example 1. Experimental data showed that, compared with Example 1, the oxygen index decreased to 23.3%, the flammability rating changed to V-1, and the oxidation induction period was shortened to 129 min. The reasons for this are as follows: Based on Comparative Example 1, removing the flame-retardant POSS further reduced the amount of flame-retardant elements, thus lowering the oxygen index; POSS (polyhedral oligomeric silsesquioxane) has a unique cage-like structure, thus possessing a relatively stable structure. Therefore, removing it reduced weather resistance and shortened the oxidation induction period.

[0048] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process method article or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process method article or apparatus.

[0049] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-strength, lightweight, weather-resistant cable for unmanned aerial vehicles (UAVs), characterized in that: It includes a conductor, an insulating layer, an aramid silicone grease sheath layer, and a polyethylene sheath layer; the insulating layer is a skin-foam-skin carbon-based coating lightweight insulation, which consists of an inner skin layer, an intermediate layer, and an outer skin layer from the inside out.

2. The manufacturing process of a high-strength, lightweight, weather-resistant cable for unmanned aerial vehicles according to claim 1, characterized in that: The conductor is a lightweight, high-strength conductor, with a structure consisting of a composite strand of 0.02-0.04mm ultra-fine silver-plated copper-clad aluminum alloy wire and carbon fiber; the inner sheath material is ethylene-tetrafluoroethylene copolymer with a thickness of 0.05-0.2mm; the middle layer is foamed ethylene-tetrafluoroethylene copolymer with a foaming degree of 40-60%; the outer sheath is a semi-conductive nano-graphite coating; and the aramid silicone grease sheath layer is a mixture of aramid and silicone grease.

3. The manufacturing process of a high-strength, lightweight, weather-resistant cable for unmanned aerial vehicles according to claim 2, characterized in that: The formation process of the semi-conductive nano-graphite coating is as follows: graphite nanoparticles are dispersed in a solvent, and then binders and additives are added to form a stable sol; the sol is coated on the surface of the substrate and cured at 500℃ for 3-5 seconds to form a semi-conductive nano-graphite coating; the coating thickness is 0.03-0.08 mm.

4. The manufacturing process of a high-strength, lightweight, weather-resistant cable for unmanned aerial vehicles according to claim 1, characterized in that: The preparation process of the polyethylene sheath layer is as follows: linear low-density polyethylene, irradiation crosslinking agent, and flame retardant POSS are mixed evenly and pre-irradiated to obtain pretreated polyethylene; the pretreated polyethylene, high-density polyethylene resin, polyolefin elastomer resin, weather-resistant modified carbon nanotubes, and magnesium calcium carbonate are mixed and stirred at 150-180℃ for 8-10 minutes and extruded to obtain a polyethylene sheath with a thickness of 1.0-1.2 mm.

5. The manufacturing process of a high-strength, lightweight, weather-resistant cable for unmanned aerial vehicles according to claim 4, characterized in that: The components of the polyethylene sheath are as follows (by weight): 20-25 parts linear low-density polyethylene, 0.2-0.3 parts irradiation crosslinking agent, 2-3 parts high-density polyethylene resin, 3-5 parts polyolefin elastomer resin, 4-5 parts flame retardant POSS, 0.25-0.30 parts weather-resistant modified carbon nanotubes, and 20-25 parts magnesium calcium carbonate; the irradiation crosslinking agent is triallyl isocyanurate.

6. The manufacturing process of a high-strength, lightweight, weather-resistant cable for unmanned aerial vehicles according to claim 4, characterized in that: Pre-irradiation treatment parameters: transfer velocity of 0.08-0.09 m / s, pre-irradiation dose of 18-20 kGy.

7. The manufacturing process of a high-strength, lightweight, weather-resistant cable for unmanned aerial vehicles according to claim 4, characterized in that: The preparation process of weather-resistant modified carbon nanotubes is as follows: Step S1: Add thionyl chloride to dimethyl sulfoxide and stir until homogeneous to obtain a thionyl chloride solution; add the thionyl chloride solution and methacrylic acid to tetrahydrofuran, stir until homogeneous, then add N,N-dimethylformamide and react at 60-65℃ for 4-5 hours. After the reaction is complete, distill under reduced pressure to obtain methacryloyl chloride. Step S2: Under nitrogen atmosphere, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid was added to anhydrous dichloromethane, stirred evenly, and then thionyl chloride was added. The mixture was refluxed at 40-45℃ for 8-10 hours. After the reaction was completed, the chlorinated antioxidant was obtained by vacuum distillation. Step S3: Hydroxylated carbon nanotubes were added to anhydrous toluene and ultrasonically dispersed until uniform. Then, 3-aminopropyltriethoxysilane was added and stirred until uniform. Deionized water was added and the mixture was stirred at 65-70℃ for 25-30 h. After the reaction was completed, the mixture was filtered, extracted, and dried to obtain aminolated carbon nanotubes. Methacrylamide chloride, chlorinated antioxidant, and hexachlorocyclotriphosphazene were added to anhydrous toluene and ultrasonically dispersed until uniform. Then, the mixture was added to the anhydrous toluene dispersion of aminolated carbon nanotubes and stirred until uniform. Triethylamine was added dropwise and the mixture was reacted at 75-80℃ for 20-30 h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain weather-resistant modified carbon nanotubes.

8. The manufacturing process of a high-strength, lightweight, weather-resistant cable for unmanned aerial vehicles according to claim 7, characterized in that: The molar ratio of thionyl chloride to methacrylic acid is 1:(1.0-1.1); the mass ratio of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid to thionyl chloride is (0.35-0.36):1.5; the mass ratio of hydroxylated carbon nanotubes to 3-aminopropyltriethoxysilane is 0.4:(1.6-1.8); and the mass ratio of methacryloyl chloride, chlorinated antioxidant, hexachlorocyclotriphosphazene, and aminolated carbon nanotubes is 0.7:(0.2-0.3):(0.8-1.0):0.

25.

9. The manufacturing process of a high-strength, lightweight, weather-resistant cable for unmanned aerial vehicles according to claim 4, characterized in that: The preparation process of flame-retardant POSS is as follows: Step S1: Add triallyl cyanurate and azobisisobutyronitrile to ethyl acetate and stir until homogeneous to obtain a triallyl cyanurate reaction solution; under nitrogen atmosphere, add 2,2'-(1,2-ethylenedioxy)diethylthiol to ethyl acetate, stir to dissolve, heat to 70-75℃, and then slowly add the triallyl cyanurate reaction solution dropwise. After the dropwise addition is complete, continue the reaction for 20-25 hours. After the reaction is complete, filter, rotary evaporate, wash, and dry to obtain a mercapto-terminated flame retardant. Step S2: Add vinyl POSS and terminal thiol flame retardant to toluene, stir evenly, and then purify by bubbling for 30-40 min. Then add azobisisobutyronitrile and continue to bubble and stir for 10-15 min. After stirring, react at 80-90℃ for 6-7 h. After the reaction is completed, dry by rotary evaporation and vacuum to obtain flame retardant POSS.

10. The manufacturing process of a high-strength, lightweight, weather-resistant cable for unmanned aerial vehicles according to claim 9, characterized in that: The reaction molar ratio of triallyl cyanurate to 2,2'-(1,2-ethylenedioxy)diethyl mercaptan is 1:(3.1-3.2); the reaction molar ratio of vinyl POSS to end-thiol flame retardant is 1:(4.5-5.0).

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