A kind of anti-interference and radiation-resistant polyolefin cable

Abstract

The present invention discloses an anti-interference and radiation-resistant polyolefin cable, belonging to the technical field of polyolefin cable manufacturing. The anti-interference and radiation-resistant polyolefin cable of the present invention comprises a conductor extruded with a semiconductor layer of a polyolefin composite shielding material containing ferrite, an insulating layer extruded outside the semiconductor layer, a braided tightening layer wrapped around, and then an inner shielding layer wrapped around, and then an oxygen-isolating layer and a ceramicized flame-retardant polyolefin composite flame-retardant layer are extruded in sequence, and a tinned copper wire is woven as an outer shielding layer, and finally coated with a halogen-free, low-smoke, flame-retardant, and radiation-resistant polyolefin mixture outer sheath. The rod-shrouded radiation-resistant polyolefin cable of the present invention has a simple structure, is easy to manufacture, has excellent mechanical properties, high voltage resistance, tensile and bending resistance, waterproofness, corrosion resistance, aging resistance, anti-interference, radiation resistance, and high and low temperature resistance, and can meet the thermal life of 110°C / 60 years and anti-interference and radiation resistance performance requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of polyolefin cable manufacturing, and in particular relates to an interference-resistant and radiation-resistant polyolefin cable and a manufacturing method thereof. Background Art

[0002] High-voltage direct current transmission has the characteristics of low loss, long distance, large capacity, convenient power connection and control, and simple adjustment. Therefore, high-voltage direct current cables need to have good electrical insulation, voltage resistance, low dielectric loss, light weight, high and low temperature stability, aging resistance, corrosion resistance, flame retardancy and mechanical properties.

[0003] At present, the main problems encountered by the insulation materials of high-voltage DC cables are the conductivity temperature characteristics and the space charge accumulation problem. The gap between the conductor and the insulation layer easily causes the space charge to accumulate, causing the material to age and crack, and finally leading to the breakdown of the material. The operating temperature of the high-voltage cable is relatively high, and the real-time temperature in an unstable state can exceed 110°C, which accelerates the aging of the insulation layer and causes breakdown. Therefore, the high-voltage DC cable requires better high-temperature stability and flame retardancy. The working environment of the high-voltage DC cable is diverse, and it is often subject to various external interferences and hazards, such as electromagnetic interference, radiation, mechanical damage, overload, overvoltage, temperature changes, etc. These factors will reduce the performance and life of the power cable, and even cause the failure or damage of the power cable. Especially in the fields of nuclear power plants, electronic communications, railway transportation, aerospace transportation, etc., the use environment of high-voltage cables is strict, and it is generally difficult to simultaneously meet the performance of high voltage resistance, electrical insulation, anti-interference, radiation resistance, flame retardancy, high temperature resistance, aging resistance, and long service life. This is also a problem that the technical personnel of the present invention strive to solve.

[0004] Chinese patent CN201721615976.5 discloses a radiation-resistant and anti-interference power cable for nuclear power plants, which includes, from the inside to the outside, a cable core formed by twisting several insulating cores, a filling layer in the gap between the cable cores, a tape layer, an inner shielding layer, a thermoplastic low-smoke, halogen-free, highly flame-retardant and radiation-resistant polyolefin inner sheath layer, an outer shielding layer and an outer sheath layer, and has excellent radiation resistance and anti-interference properties. However, the inner and outer shielding layers of the patent both adopt a tinned copper wire braided structure, which has a high production cost, and the shielding effect of the braided cable is unstable, and the heat transfer capacity is poor, which affects the final shielding effect and incineration problem; the polyolefin material mentioned in the patent is not described in detail, and its final use effect is not clear, it may not meet the use requirements of high-voltage DC cables, and radiation resistance is not involved. Invention patent CN201911309331.2 discloses an anti-interference, highly flame-retardant and environmentally friendly transponder data transmission cable, which uses a double composite high electromagnetic shielding layer to form a three-level shielding, has strong anti-interference ability, and reduces the amount of smoke and toxic gases generated by combustion to a minimum. However, the insulation layer of this patent uses high-temperature resistant fluoroplastics, which does not belong to the development trend of halogen-free cables; the semiconductor nylon tape coated on the outside of the cable core is prone to static electricity accumulation during long-term operation, which affects the insulation of the cable, and the elongation performance is general. In low-temperature environments, it is easy to crack, which in turn affects the quality and service life of high-voltage cables. Invention patent CN201911088055.1 discloses a thermoplastic radiation-resistant halogen-free low-smoke flame-retardant sheath material for nuclear power plant cables. It uses high-temperature resistant polyolefin elastomers and asymmetric hindered phenol-type cup aromatics as the main antioxidants and a material system containing condensed polycyclic polynuclear aromatic resins, so that the sheath material can achieve 90°C / 60 years of thermal life and radiation resistance requirements, and has high flame retardant properties. However, the real-time temperature of high-voltage cables in unstable states can be as high as 110°C. The sheath material of this patent cannot meet the use of high-voltage cables, and its corrosion resistance is general. Summary of the invention

[0005] The main purpose of the present invention is to provide an interference-resistant and radiation-resistant polyolefin cable, which has a simple structure, is easy to manufacture, and has excellent mechanical properties, high pressure resistance, tensile and bending resistance, waterproofness, corrosion resistance, aging resistance, anti-interference, radiation resistance and high and low temperature resistance. At the same time, the combustion performance of the polyolefin cable is halogen-free low-smoke flame retardant Class A, and the grade can reach B1 level. At the same time, it can meet the thermal life and interference-resistant radiation performance requirements of 110°C / 60 years.

[0006] In order to achieve the purpose of the present invention, the present invention provides an anti-interference and radiation-resistant polyolefin cable, comprising a cable core, a tightening layer, an inner shielding layer, an oxygen barrier layer, a flame retardant layer, an outer shielding layer and an outer sheath, wherein the cable core is one or more wire cores, the wire core comprises a conductor, a semiconductor layer and an insulating layer, the conductor is extruded with a semiconductor layer, and the semiconductor layer is extruded with an insulating layer;

[0007] The outer side of the insulating layer is woven with a tightening layer made of Kevlar and polyester fibers, the outer side of the tightening layer is wrapped with an inner shielding layer, the outer side of the inner shielding layer is extruded with an oxygen-isolating layer, the outer side of the oxygen-isolating layer is extruded with a flame-retardant layer, the outer side of the flame-retardant layer is woven with tinned copper wire as an outer shielding layer, and the outer shielding layer is covered with an outer sheath;

[0008] The semiconductor layer is a polyolefin composite shielding material containing ferrite;

[0009] The flame retardant layer is a ceramic flame retardant polyolefin composite material;

[0010] The outer protective layer is a halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture.

[0011] Furthermore, when the cable core is composed of one wire core, the tightening layer is directly woven outside the insulating layer; when the cable core is composed of two or more wire cores, the multiple wire cores are twisted to form the cable core, and then the filling rope is filled in the gap between the cable cores, and then the tightening layer is woven.

[0012] Furthermore, the polyolefin composite shielding material is composed of the following raw materials in parts by mass: 40-60 parts of polypropylene resin, 25-35 parts of ethylene-vinyl acetate copolymer, 15-25 parts of ethylene-butyl acrylate copolymer, 5-10 parts of PP grafted maleic anhydride, 5-15 parts of carbon black, 3-6 parts of barium ferrite, 0.1-0.5 parts of initiator DCP, 0.5-2 parts of the first silane coupling agent, 0.3-0.5 parts of antioxidant, and 1-3 parts of lubricant.

[0013] Furthermore, the preparation method of the barium ferrite is:

[0014] S1. Add appropriate proportions of ferrous nitrate, ferric nitrate and polyethylene glycol to an appropriate amount of deionized water and stir continuously until dissolved, then add ammonia water to adjust the pH value to 10-11, heat to 50-70 ° C for 2-4h, filter, wash and dry to obtain an iron oxide precursor;

[0015] S2. The iron oxide precursor and barium carbonate prepared above are added to glacial acetic acid and stirred until dissolved to form a mixed solution;

[0016] S3. Add an appropriate amount of dilute nitric acid to the mixed solution, stir for 5-10 minutes, then heat to 200-220°C to react for 3-5 hours, cool to room temperature, filter, and then wash with deionized water and anhydrous ethanol 2-3 times in succession, and vacuum dry at 80°C for 2-5 hours to obtain barium ferrite.

[0017] Furthermore, the molar ratio of ferrous nitrate to ferric nitrate is (0.4-0.6):1;

[0018] The molar ratio of iron to barium carbonate in the iron oxide precursor is (9-10):1.

[0019] Furthermore, the flame retardant is composed of microencapsulated red phosphorus and organic montmorillonite in a ratio of 1:4 by mass.

[0020] Furthermore, the ceramic flame-retardant polyolefin composite material is composed of the following raw materials in parts by weight:

[0021] 30-50 parts of low-density polyethylene, 15-30 parts of ethylene-methyl acrylate copolymer, 40-60 parts of ethylene propylene diene terpolymer, 30-50 parts of aminosilane-coated wollastonite, 10-20 parts of low-melting-point glass powder, 15-25 parts of phlogopite powder, 5-10 parts of lithium borate salt, 0.2-0.4 parts of initiator DCP, 6-12 parts of halogen-free flame retardant and 1-3 parts of second silane coupling agent.

[0022] Furthermore, the aminosilane-coated wollastonite uses aminopropyltriethoxysilane to perform surface modification on the wollastonite, and the coating rate is ≥70%;

[0023] The lithium borate salt is composed of lithium tetraborate, lithium metaborate and zinc borate in a mass ratio of 1:2:4;

[0024] The halogen-free flame retardant is composed of nano magnesium hydroxide, magnesium stearate and silicone oil in a mass ratio of (0.2-0.5):1:1;

[0025] The second silane coupling agent is composed of vinyltrimethoxysilane and aminopropyltriethoxysilane in a mass ratio of 3:2.

[0026] Furthermore, the halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture is composed of the following raw materials in parts by mass: 30-50 parts of linear low-density polyethylene, 20-40 parts of ethylene-methyl acrylate copolymer, 20-40 parts of ethylene-octene copolymer, 5-10 parts of polyimide resin, 20-40 parts of low-melting point glass powder, 10-20 parts of epoxy soybean oil, 20-40 parts of composite flame retardant, 10-15 parts of nickel aluminum oxide, 20-40 parts of filler, 0.2-0.4 parts of antioxidant 168, 0.1-0.3 parts of initiator DCP, and 3-5 parts of a third silane coupling agent.

[0027] Furthermore, the composite flame retardant is composed of the following raw materials in parts by mass: 40-60 parts of nano magnesium hydroxide, 10-20 parts of aluminum hydroxide and 30-40 parts of manganese borate.

[0028] Furthermore, the nickel aluminum oxide is a mixture of nickel oxide and aluminum oxide in a mass ratio of 1:3;

[0029] The filler is composed of calcined kaolin and phlogopite powder in a mass ratio of 1:2;

[0030] The third silane coupling agent is a mixture of vinyltrimethoxysilane and 2-aminoethyl-aminopropyltrimethoxysilane in a mass ratio of 2:3.

[0031] Furthermore, the insulating layer is a polyolefin elastomer insulating material resistant to high temperatures of 150°C;

[0032] The tightening layer is a fiber interlaced structure composed of equal amounts of Kevlar and polyester fibers;

[0033] The inner shielding layer is an aluminum foil Mylar tape;

[0034] The oxygen barrier layer is a low-smoke, halogen-free, flame-retardant cable material with an oxygen index greater than or equal to 40;

[0035] The outer shielding layer is woven from tinned copper wires, with a braiding angle of 30-45° and a coverage rate of more than 80%.

[0036] The present invention has achieved the following beneficial effects:

[0037] 1. The present invention adopts a ferrite-containing polyolefin composite shielding material as a semiconductor layer and extrude it on the conductor, so that the conductor and the insulating layer are closely connected, which significantly reduces the local discharge of the insulating layer and significantly improves the electromagnetic shielding performance of the cable. At the same time, it also plays a role of radiation resistance, and also reduces the resistivity and cost, thereby extending the service life of the polyolefin cable.

[0038] 2. The present invention adopts an aluminum foil Mylar tape inner shielding layer and a tinned copper braided outer shielding layer to form a double-layer electromagnetic shielding, which together with the semiconductor layer constitutes a multi-layer shielding, which greatly reduces the signal interference and space charge accumulation problems of the polyolefin cable, and at the same time improves the radiation resistance, high temperature resistance and flame retardancy of the cable.

[0039] 3. The base materials of the insulating layer, oxygen barrier layer, flame retardant layer and outer sheath of the present invention are all polyolefins, which are halogen-free and environmentally friendly, ensuring that the polyolefin cable still has excellent mechanical strength, electrical insulation, tensile and bending resistance, waterproofness, corrosion resistance, aging resistance and high and low temperature stability under high voltage conditions, and can still reach a service life of 60 years when used at 110°C; the combustion performance of the polyolefin cable is halogen-free low-smoke flame retardant Class A, and the grade can reach Class B1.

[0040] 4. The anti-interference and radiation-resistant polyolefin cable product prepared by the present invention has a simple structure, is easy to manufacture, has a wide range of applications, and is low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic structural diagram of a single-core cable of the anti-interference and radiation-resistant polyolefin cable of the present invention;

[0042] Figure 2 The present invention is a schematic structural diagram of a three-core polyolefin cable that is anti-interference and radiation-resistant.

[0043] Figure symbols: 1. conductor; 2. semiconductor layer; 3. insulating layer; 4. tightening layer; 5. inner shielding layer; 6. oxygen barrier layer; 7. flame retardant layer; 8. outer shielding layer; 9. outer sheath; 10. filling rope. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] like Figure 1 As shown, the present invention provides an interference-resistant and radiation-resistant polyolefin cable, comprising a cable core, a tightening layer 4, an inner shielding layer 5, an oxygen insulation layer 6, a flame retardant layer 7, an outer shielding layer 8 and an outer sheath 9, wherein the cable core is one or more wire cores, and the wire core comprises a conductor 1, a semiconductor layer 2 and an insulating layer 3.

[0046] When the cable core is a wire core (such as Figure 1 When the conductor 1 is extruded with a semiconductor layer 2, the semiconductor layer 2 is extruded with an insulating layer 3, the insulating layer 3 is woven with a tightening layer 4 made of Kevlar and polyester fibers, the tightening layer 4 is wrapped with an inner shielding layer 5, the inner shielding layer 5 is extruded with an oxygen-isolating layer 6, the oxygen-isolating layer 6 is extruded with a flame-retardant layer 7, the flame-retardant layer 7 is woven with tinned copper wire as an outer shielding layer 8, and the outer shielding layer 8 is covered with an outer sheath 9. The present invention mainly takes a single-core cross-linked polyolefin cable as an embodiment.

[0047] When the cable core is composed of two or more wire cores (such as Figure 2 As shown, when there are 3 cores), the 3 cores are twisted to form a cable core, and then the filling rope 10 is filled in the gap between the cable cores, and then the tightening layer 4 is braided.

[0048] Preferably, the semiconductor layer 2 is a ferrite-containing polyolefin composite shielding material, which can significantly improve the anti-interference and radiation resistance of the cable of the present invention, and reduce the resistivity and cost, ensure the smooth surface of the inner shielding layer 5, and further prevent the electric field distortion from damaging the insulating layer 3, thereby extending the service life of the cable of the present invention.

[0049] The polyolefin composite shielding material is composed of the following raw materials in parts by mass: 40-60 parts of polypropylene resin, 25-35 parts of ethylene-vinyl acetate copolymer, 15-25 parts of ethylene-butyl acrylate copolymer, 5-10 parts of PP grafted maleic anhydride, 5-15 parts of carbon black, 3-6 parts of barium ferrite, 0.1-0.5 parts of initiator DCP, 0.5-2 parts of first silane coupling agent, 0.3-0.5 parts of antioxidant, and 1-3 parts of lubricant. The raw material combination and proportion of the polyolefin composite shielding material ensure that the present invention has good anti-interference, mechanical properties and combustion performance, and together with the inner shielding layer 5 and the outer shielding layer 8, it forms a multi-layer shielding, greatly reducing the signal interference and space charge accumulation problems of the polyolefin cable, and can interact with each component of the cable to ensure that it has excellent comprehensive performance.

[0050] Polypropylene resin (selected from Korean Lotte's polypropylene JI-320), ethylene-vinyl acetate copolymer (selected from Japan Mitsui's EVA 45X) and ethylene-butyl acrylic acid copolymer (selected from Dow's EBA 3217) are selected and combined in appropriate proportions to ensure that the polyolefin composite shielding material has easy processing, better mechanical properties and ductility, and improves the crosslinking density and temperature resistance level. PP grafted maleic anhydride (selected from SK Chemical's The addition of 18730 improves the compatibility between PP and other components, making the components closely bonded, thereby improving the mechanical properties and tensile and bending properties of the inner shielding layer 5. The use of carbon black (acetylene carbon black selected from Tianjin Huacai Chemical) improves the conductivity of the polyolefin composite shielding material and reduces the cost; however, if the amount of carbon black added is too much, the inner shielding layer 5 prepared is brittle, has poor ductility, low elongation at break, and affects the smoothness of the surface of the inner shielding layer 5, thereby affecting the mechanical properties and flexibility of the cable, and easily causing electric field distortion to damage the insulating layer 3, reducing the service life of the cable; if the amount of carbon black is too little, the conductivity of the inner shielding layer 5 cannot be guaranteed, reducing the anti-interference performance of the cable, etc.

[0051] The present invention uses carbon black and barium ferrite in appropriate proportions, which not only improves the conductivity of the inner shielding layer 5, but also improves the high temperature resistance and wear resistance of the cable of the present invention, so that the cable has better anti-interference, radiation resistance and corrosion resistance, and also ensures that the inner shielding layer 5 has excellent mechanical strength, flexibility, and surface smoothness, thereby extending the high temperature service life of the cable.

[0052] Preferably, barium ferrite BaFe 12 O 19 Commercially available or homemade ones can be selected, wherein the commercially available barium ferrite is selected from Wuhan Langbowan Biomedicine Company.

[0053] Homemade barium ferrite BaFe 12 O19 The specific preparation process is:

[0054] S1. Add 371.8 g of ferrous nitrate, 1 kg of ferric nitrate (i.e., the molar ratio of ferrous nitrate to ferric nitrate is 1:2) and 96 g of PEG8000 into 1.2 L of deionized water and stir continuously until dissolved, then add ammonia water to adjust the pH value to 11, heat to 60 ° C for 4 h, filter, wash and dry to obtain an iron oxide precursor;

[0055] S2. The iron oxide precursor prepared above and 122.4 g of barium carbonate (ie, the molar ratio of iron to barium carbonate in the iron oxide precursor is 10:1) are added to 1 L of glacial acetic acid and stirred until dissolved to form a mixed solution;

[0056] S3. Add 700 mL of 4 mol / L dilute nitric acid to the above mixed solution, stir for 10 min, then heat to 220 °C to react for 4 h, cool to room temperature, filter, then wash with deionized water and anhydrous ethanol three times in succession, and vacuum dry at 80 °C for 3 h to obtain barium ferrite.

[0057] The barium ferrite BaFe prepared by the present invention 12 O 19 The preparation method is easy to operate, and the barium ferrite obtained has a small grain size, good dispersibility, and few impurities, which can significantly improve the conductivity and anti-interference properties of the inner shielding layer 5, and can also significantly improve the radiation resistance and corrosion resistance of the present invention, and ensure that the mechanical strength, flexibility, surface smoothness, etc. of the inner shielding layer 5 meet the cable requirements.

[0058] Preferably, the first silane coupling agent is vinyltrimethoxysilane, which, on the one hand, is to improve the bonding force between the organic and inorganic components in the polyolefin composite shielding material, thereby improving the mechanical strength of the inner shielding layer 5; on the other hand, it increases the crosslinking density between polyolefin resins, further improving the mechanical properties, anti-interference, anti-radiation, high temperature resistance and other properties of the polyolefin composite shielding material.

[0059] Preferably, the antioxidant is antioxidant 1010, which improves the heat-oxidative aging resistance of the polyolefin composite shielding material, is not easy to migrate, and has high thermal stability. The lubricant is CYD-P214, which improves the processing fluidity and dimensional stability of the polyolefin composite shielding material.

[0060] Preferably, the insulating layer 3 is a polyolefin elastomer insulation material resistant to high temperatures of 150°C, which is halogen-free, non-toxic and environmentally friendly, and can effectively protect the electrical properties of the conductor, ensuring that the polyolefin cable has excellent insulation and flame retardancy, and improving the mechanical properties, aging resistance, corrosion resistance and high and low temperature resistance of the cable (high temperature resistance of 150°C and low temperature resistance of below -50°C). In the embodiment of the present invention, the polyolefin elastomer insulation material resistant to high temperatures of 150°C is selected from the 150°C irradiated cross-linked polyolefin in-vehicle high-voltage wire material produced by Oulong Youxin Materials, model JL150H-819.

[0061] Preferably, the tightening layer 4 is a fiber interlaced structure composed of equal numbers of Kevlar and polyester fibers, which provides armor protection for the cable core, improves the firmness of the cable core, makes the insulating layer 3 in close contact with the cable core, and reduces space charge accumulation.

[0062] Preferably, the inner shielding layer 5 is an aluminum foil Mylar tape, which provides three-layer protection together with the semiconductor layer 2 and the outer shielding layer 8, further improving the anti-interference, radiation resistance and other properties of the cable of the present invention, while improving the high temperature resistance, fire retardancy and stability of the cable of the present invention.

[0063] Preferably, the oxygen barrier layer 6 is a low-smoke halogen-free flame-retardant cable material with an oxygen index greater than or equal to 40. The oxygen barrier layer 6 is used to protect the insulating layer 3 and the tightening layer 4. When a fire occurs, it delays the ignition time of the conductor, reduces losses, and ensures that the present invention has good insulation and electrical properties. In the embodiment of the present invention, the low-smoke halogen-free flame-retardant cable material is selected from EPC6909 of Yangzhong Oubao Chemical.

[0064] Preferably, the flame retardant layer 7 is a ceramic flame retardant polyolefin composite material, which has high mechanical strength and chemical stability, can be used for a long time at 150°C, and can form a ceramic body during the combustion process in the flame, which significantly improves the fire retardancy, smoke suppression and thermal insulation properties, and the oxygen index is ≥35. It also has a supporting function, improves the wear resistance and corrosion resistance of the cable, and has good thermal shock resistance and electrical properties.

[0065] The ceramic flame-retardant polyolefin composite material is composed of the following raw materials in parts by mass: 30-50 parts of low-density polyethylene, 15-30 parts of ethylene-methyl acrylate copolymer, 40-60 parts of ethylene-propylene diene terpolymer, 30-50 parts of aminosilane-coated wollastonite, 10-20 parts of low-melting-point glass powder, 15-25 parts of phlogopite powder, 5-10 parts of lithium borate salt, 0.2-0.4 parts of initiator DCP, 6-12 parts of halogen-free flame retardant and 1-3 parts of a second silane coupling agent.

[0066] In order to ensure that the present invention has excellent mechanical properties, combustion performance and non-corrosiveness, the present invention preferably has a low-density polyethylene melt index of 1.5-4g / 10min at 190°C and 2.16Kg load (Shanghai Petrochemical's DJ210 is selected in the present embodiment); an ethylene-methyl acrylate copolymer melt index of 5-10g / 10min at 190°C and 2.16Kg load (Arkema's LOTADER AX8900 is selected in the present embodiment); an ethylene content of 40-55wt% and a propylene content of 40-50wt% in the ethylene-propylene diene terpolymer (Dow's EPDM565 is selected in the present embodiment). The performance settings and combination of low-density polyethylene, ethylene-methyl acrylate copolymer and EPDM can enable the present invention to burn for 20min under a fire source with a power of 20.5kW without any dripping during the period; the present invention burns at 935°C with a conductivity of ≤10μs / mm and a pH of ≥4.

[0067] Aminosilane coated wollastonite, low melting point glass powder and phlogopite powder are added as ceramic fillers of the ceramic material, which not only has good bonding strength with the polyolefin material, but also improves the mechanical strength, electrical insulation, high temperature resistance and corrosion resistance of the cable of the present invention.

[0068] The addition of low-melting-point glass powder improves the mechanical strength, corrosion resistance, wear resistance, high temperature resistance and combustion performance of the ceramic flame-retardant polyolefin composite material, and further ensures that the cable of the present invention meets the requirements of halogen-free low-smoke flame-retardant Class A, and the combustion performance level reaches the national standard B1 level. At the same time, it also improves the electrical insulation and arc resistance of the high-voltage cable. In order to improve the use effect of low-melting-point glass powder in ceramic flame-retardant polyolefin composite materials, preferably, the melting temperature of the low-melting-point glass powder is 350℃-550℃, and the average particle size is not more than 10μm. The melting temperature of the low-melting-point glass powder selected in the embodiment of the present invention is 350℃, and it is sieved through 2000 mesh.

[0069] Aminosilane coated wollastonite uses aminopropyl triethoxysilane to modify the surface of wollastonite (selected from Jiangxi Kete fine 400 mesh needle-shaped wollastonite powder), with a coating rate of ≥70%, which improves the bonding force between wollastonite and other components, thereby ensuring that the ceramic flame-retardant polyolefin composite material can achieve the mechanical strength and combustion performance required by the present invention. The addition of phlogopite powder can form a whole with the outer protective layer 9 during the combustion process, forming a drip-free ceramic body, and improving the fire retardant performance.

[0070] Preferably, the lithium borate salt is composed of lithium tetraborate, lithium metaborate and zinc borate in a mass ratio of 1:2:4. The use of the lithium borate salt in this combination can not only reduce the ceramic transition temperature of the ceramic flame retardant polyolefin composite material and improve the processing performance, but also significantly improve the mechanical strength and flame retardancy of the ceramic flame retardant polyolefin composite material.

[0071] Preferably, the halogen-free flame retardant is composed of nano magnesium hydroxide, magnesium stearate and silicone oil in a mass ratio of (0.2-0.5): 1: 1. The use of this combination of halogen-free flame retardants not only has excellent flame retardancy, but also ensures that the ceramic flame retardant polyolefin composite material has excellent mechanical strength and processing properties. The halogen-free flame retardant selected in the embodiment of the present invention is a mixture of nano magnesium hydroxide, magnesium stearate and silicone oil in a mass ratio of 1: 2: 2.

[0072] Preferably, the second silane coupling agent is composed of vinyl trimethoxy silane and aminopropyl triethoxy silane in a mass ratio of 3: 2. The combined silane coupling agent increases the crosslinking density between polyolefin resins and improves the mechanical properties, water resistance and high temperature resistance of the ceramic flame retardant polyolefin composite material.

[0073] Preferably, the outer shielding layer 8 is woven from tinned copper wires, with a braiding angle of 30-45° and a coverage rate of more than 80%. Using tinned copper wires as the outer shielding layer 8 not only improves the shielding efficiency of the cable of the present invention in high-frequency applications, but also improves the mechanical strength, anti-oxidation, corrosion resistance and other properties of the cable, and at the same time, ensures that the present invention has better waterproof, flame retardant and radiation resistance.

[0074] Preferably, the outer sheath 9 is a halogen-free, low-smoke, flame-retardant, and radiation-resistant polyolefin mixture, which can withstand high temperatures of 150°C and low temperatures of -50°C, has an oxygen index ≥35, and has excellent mechanical properties, fire retardancy, anti-interference, corrosion resistance, radiation resistance, and electrical insulation.

[0075] The halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture is composed of the following raw materials in parts by mass: 30-50 parts of linear low-density polyethylene, 20-40 parts of ethylene-methyl acrylate copolymer, 20-40 parts of ethylene-octene copolymer, 5-10 parts of polyimide resin, 20-40 parts of low-melting point glass powder, 10-20 parts of epoxy soybean oil (ESO selected from Qilu Petrochemical in the embodiment of the present invention), 20-40 parts of composite flame retardant, 10-15 parts of nickel aluminum oxide, 20-40 parts of filler, 0.2-0.4 parts of antioxidant 168, 0.1-0.3 parts of initiator DCP, and 3-5 parts of a third silane coupling agent.

[0076] In order to ensure that the present invention has excellent mechanical properties, combustion performance and corrosion resistance, the present invention preferably has a linear low-density polyethylene melt index of 1.5-3 g / 10 min at 190°C and a load of 2.16 kg (DFDA-7042 of Maoming Petrochemical is selected in the embodiment of the present invention); an ethylene-methyl acrylate copolymer melt index of 5-10 g / 10 min at 190°C and a load of 2.16 kg (LOTADER AX8900 of Arkema is selected in the embodiment of the present invention); an ethylene-octene copolymer melt index of 3-8 g / 10 min at 190°C and a load of 2.16 kg (Choose Dow's ENGAGE TM 8200). The performance and proportion of these components can be set to ensure that the outer sheath of the present invention has excellent comprehensive performance and has better mechanical strength, flame retardancy, corrosion resistance and aging resistance.

[0077] The polyimide resin has good compatibility in the halogen-free, low-smoke, flame-retardant, and radiation-resistant polyolefin mixture. After being added, the mechanical strength, high and low temperature resistance, flame retardancy, and corrosion resistance of the halogen-free, low-smoke, flame-retardant, and radiation-resistant polyolefin mixture are significantly improved, and the radiation resistance and electrical insulation of the present invention are also greatly improved. In the embodiment of the present invention, the polyimide resin is preferably selected from PI 3000T of Mitsui Chemicals of Japan.

[0078] The addition of low melting point glass powder improves the mechanical strength, corrosion resistance, wear resistance, high temperature resistance and combustion performance of the halogen-free, low smoke, flame retardant and radiation resistant polyolefin mixture. In the embodiment of the present invention, the low melting point glass powder is preferably selected from Hebei Jinghang, with a melting temperature of 350°C and sieved through 2000 mesh.

[0079] Preferably, the composite flame retardant is composed of the following raw materials in parts by mass: 40-60 parts of nano magnesium hydroxide, 10-20 parts of aluminum hydroxide and 30-40 parts of manganese borate. The composite flame retardant can ensure that the halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture has excellent low-smoke flame retardancy, can form a non-drip hard shell-like substance during the combustion process, and can also ensure that the halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture has excellent mechanical strength, anti-interference, radiation resistance and processing performance. In the embodiment of the present invention, the formula of the composite flame retardant is: 50 parts of nano magnesium hydroxide (in the embodiment, it is selected from 5000 mesh nano magnesium hydroxide of Jiuzhuo Chemical), 18 parts of aluminum hydroxide (in the embodiment, it is selected from FR3801 of Zhongke Flame Retardant, with a particle size of 8000 mesh) and 32 parts of manganese borate (in the embodiment, it is selected from Hubei Jusheng Technology).

[0080] Preferably, nickel aluminum oxide is a mixture of nickel oxide and aluminum oxide in a mass ratio of 1:3, which can improve the corrosion resistance and radiation resistance of the outer protective layer 9, and enable the outer protective layer 9 to achieve the mechanical strength, high temperature resistance, wear resistance, anti-interference and flame retardancy required by the present invention.

[0081] Preferably, the filler is composed of calcined kaolin (i.e., calcined kaolin YF-4000) and phlogopite powder (calcined phlogopite powder selected from Deqian mineral products) in a mass ratio of 1:2, which improves the mechanical strength, flame retardancy, corrosion resistance and wear resistance of the halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture.

[0082] Preferably, antioxidant 168 not only improves the heat-oxidative aging resistance and migration resistance of the halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture, but also improves the anti-interference and radiation resistance properties of the present invention.

[0083] Preferably, the third silane coupling agent is composed of a mixture of vinyltrimethoxysilane and 2-aminoethyl-aminopropyltrimethoxysilane in a mass ratio of 2:3, which increases the crosslinking density between polyolefin resins and improves the mechanical properties, water resistance and high temperature resistance of the halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture.

[0084] The present invention also provides a method for preparing an interference-resistant and radiation-resistant polyolefin cable (hereinafter referred to as a single-core cable), which specifically comprises the following steps:

[0085] P1. The tinned copper wire is twisted by a cantilever single twisting machine to form a single conductor 1;

[0086] P2. The raw materials in the above-mentioned ferrite-containing polyolefin composite shielding material are weighed by mass, added into a high-speed mixer, mixed for 8-10 minutes at 480r / min and 110-120°C, cooled to below 50°C, and then conveyed to a twin-screw extruder for granulation to obtain a polyolefin composite shielding material; then, an extruder is used to extrude and coat the above-prepared polyolefin composite shielding material on the conductor 1 at a temperature of 130-150°C to form a semiconductor layer 2;

[0087] P3. The high temperature resistant 150 ℃ polyolefin elastomer insulation material is extruded on the semiconductor layer 2 by an extruder to form an insulating layer 3;

[0088] P4. An equal number of Kevlar and polyester fiber woven fabrics are fixed to the outer periphery of the insulating layer 3 by a cable wrapping machine to form a tightening layer 4;

[0089] P5. The aluminum foil Mylar tape is fixed to the outer periphery of the tightening layer 4 through a cable wrapping machine to form an inner shielding layer 5;

[0090] P6. Wrap the inner shielding layer 5 with a low-smoke halogen-free flame-retardant cable material having an oxygen index greater than or equal to 40 to form an oxygen barrier layer 6;

[0091] P7. The raw materials in the ceramic flame-retardant polyolefin composite material are weighed by mass, added into a high-speed mixer, mixed for 10-15 minutes at 480r / min and 100-110°C, cooled to below 70°C, and then transported to a twin-screw extruder for granulation to obtain a ceramic flame-retardant polyolefin composite material; then, an extruder is used to extrude and coat the ceramic flame-retardant polyolefin composite material obtained above on the oxygen barrier layer 6 at a temperature of 125-135°C to form a flame-retardant layer 7;

[0092] P8. The tinned copper wire is braided at a braiding angle of 40° and a coverage of 85% on the flame retardant layer 7 to form an outer shielding layer 8;

[0093] P9. Weigh the above-mentioned halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture according to the mass fraction, add it into a high-speed mixer, mix it at 480r / min and 110-120℃ for 8-10min, cool it to below 70℃, and then convey it to a twin-screw extrusion granulation to obtain a halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture; then use an extruder at a temperature of 120-140℃ to extrude and coat the above-mentioned halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture on the outer shielding layer 8 to form an outer protective layer 9.

[0094] The anti-interference and radiation-resistant polyolefin cable of the present invention is described below in conjunction with specific embodiments.

[0095] Semiconductor layer 2: Polyolefin composite shielding material containing ferrite

[0096] Example 1

[0097] The ferrite-containing polyolefin composite shielding material is composed of the following raw materials in parts by mass: 50 parts of polypropylene resin, 32 parts of ethylene-vinyl acetate copolymer, 18 parts of ethylene-butyl acrylate copolymer, 8 parts of PP grafted maleic anhydride, 10 parts of carbon black, 5 parts of barium ferrite, 15 parts of flame retardant, 0.4 parts of initiator DCP, 1.5 parts of first silane coupling agent, 0.4 parts of antioxidant 1010, and 1.5 parts of lubricant CYD-P214.

[0098] The raw materials, raw material models and preparation process of the ferrite-containing polyolefin composite shielding material are all described in the above specific embodiments, and please refer to the above description for details. In addition, the barium ferrite in Example 1 is selected from the commercially available Wuhan Langbowan Biomedicine Company.

[0099] After testing, the tensile strength of Example 1 is 23.4 MPa, the elongation at break is 378.5%, the volume resistivity at 20°C is 6.8Ω·cm, the volume resistivity at 90°C is 20.4Ω·cm, and the melt index is 6.8 g / 10min; when the gamma ray is 1000 kGy at room temperature, the tensile strength is 21.6 MPa, and the elongation at break is 349.5%.

[0100] Example 2

[0101] The raw materials, components and preparation process of the ferrite-containing polyolefin composite shielding material of Example 2 are the same as those of Example 1, and specific reference is made to Example 1. The difference is that the barium ferrite of Example 2 is homemade, and the specific preparation method please refer to the description in the above specific implementation manner.

[0102] After testing, the tensile strength of Example 2 is 26.9 MPa, the elongation at break is 425.6%, the volume resistivity at 20°C is 4.3Ω·cm, the volume resistivity at 90°C is 12.5Ω·cm, and the melt index is 8.2 g / 10min; when the gamma ray is 1000 kGy at room temperature, the tensile strength is 25.3 MPa, and the elongation at break is 396.7%.

[0103] Comparative Example 1

[0104] The preparation method of the polyolefin composite shielding material of Comparative Example 1 is the same as that of Example 2, with specific reference to Example 1, except that barium ferrite is not added in Comparative Example 1, and the amount of carbon black added is 15 parts.

[0105] After testing, the tensile strength of Comparative Example 1 is 21.6 MPa, the elongation at break is 327.5%, the volume resistivity at 20°C is 15.3Ω·cm, the volume resistivity at 90°C is 42.8Ω·cm, and the melt index is 5.6 g / 10min; when the gamma ray is 1000 kGy at room temperature, the tensile strength is 15.2 MPa, and the elongation at break is 268.7%.

[0106] Comparative Example 2

[0107] The preparation method of the polyolefin composite shielding material of Comparative Example 2 is the same as that of Example 2, specifically referring to Example 1, except that barium ferrite is not added in Comparative Example 2, and the amount of carbon black added is 25 parts.

[0108] After testing, the tensile strength of Comparative Example 2 is 12.8 MPa, the elongation at break is 185.4%, the volume resistivity at 20°C is 9.5Ω·cm, the volume resistivity at 90°C is 25.8Ω·cm, and the melt index is 4.5g / 10min; when the gamma ray is 1000kGy at room temperature, the tensile strength is 8.6MPa, and the elongation at break is 123.5%.

[0109] Comparative Example 3

[0110] The polyolefin composite shielding material of Comparative Example 3 is prepared in the same manner as in Example 2, specifically referring to Example 1, except that the flame retardant in Comparative Example 3 is composed of microencapsulated red phosphorus and magnesium hydroxide in a mass ratio of 1:9.

[0111] After testing, the tensile strength of Comparative Example 3 is 22.5 MPa, the elongation at break is 368.5%, the volume resistivity at 20°C is 5.2Ω·cm, the volume resistivity at 90°C is 15.9Ω·cm, and the melt index is 6.5 g / 10 min.

[0112] Flame retardant layer 7: ceramic flame retardant polyolefin composite material

[0113] Example 3

[0114] The ceramic flame-retardant polyolefin composite material is composed of the following raw materials in parts by mass: 38 parts of low-density polyethylene, 25 parts of ethylene-methyl acrylate copolymer, 37 parts of ethylene propylene diene terpolymer, 40 parts of aminosilane-coated wollastonite, 16 parts of low-melting-point glass powder, 18 parts of phlogopite powder, 8 parts of lithium borate salt, 0.3 parts of initiator DCP, 10 parts of halogen-free flame retardant and 1.8 parts of a second silane coupling agent.

[0115] The raw materials, raw material models, and preparation process of the ceramic flame-retardant polyolefin composite material are all described in the above specific implementation manner. Please refer to the above description for details.

[0116] Comparative Example 4

[0117] The ceramic flame-retardant polyolefin composite material of Comparative Example 4 is prepared in the same manner as in Example 3, with specific reference to Example 3, except that the wollastonite in Comparative Example 4 is not coated with aminosilane, that is, fine 400-mesh needle-shaped wollastonite powder from Jiangxi Kete is directly added.

[0118] Comparative Example 5

[0119] The ceramic flame-retardant polyolefin composite material of Comparative Example 5 is prepared in the same manner as in Example 3, with specific reference to Example 3, except that no phlogopite mica powder is added in Comparative Example 6, and the amount of low-melting-point glass powder added is 34 parts.

[0120] Comparative Example 6

[0121] The ceramic flame-retardant polyolefin composite material of Comparative Example 6 is prepared in the same manner as in Example 3, with specific reference to Example 3, except that zinc borate is not added in Comparative Example 5, and the mass ratio of lithium tetraborate to lithium metaborate is 1:2.

[0122] The ceramic flame-retardant polyolefin composite materials prepared in the above Example 3 and Comparative Examples 4-6 were made into test specimens for performance testing, as shown in Table 1 below.

[0123] Table 1 Performance test results of ceramic flame retardant polyolefin composites

[0124]

[0125]

[0126] It can be seen from the experimental results in Table 1 above that the ceramic flame-retardant polyolefin composite material of the present invention has high mechanical strength, chemical stability and flame retardancy, and can be used for a long time at 150°C.

[0127] Outer sheath 9: Halogen-free, low-smoke, flame-retardant, radiation-resistant polyolefin mixture

[0128] Example 4

[0129] The halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture is composed of the following raw materials in parts by mass: 42 parts of linear low-density polyethylene, 26 parts of ethylene-methyl acrylate copolymer, 32 parts of ethylene-octene copolymer, 8 parts of polyimide resin, 28 parts of low-melting point glass powder, 12 parts of epoxy soybean oil, 35 parts of composite flame retardant, 12 parts of nickel aluminum oxide, 30 parts of filler, 1680.32 parts of antioxidant, 0.15 parts of initiator DCP and 4.2 parts of third silane coupling agent.

[0130] The raw materials, raw material models, and preparation process of the halogen-free, low-smoke, flame-retardant, and radiation-resistant polyolefin mixture are all described in the above specific implementation manner. Please refer to the above description for details.

[0131] Comparative Example 7

[0132] The preparation method of the halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture of Comparative Example 7 is the same as that of Example 4, with specific reference to Example 4, except that no polyimide resin is added in Comparative Example 7.

[0133] Comparative Example 8

[0134] The halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture of Comparative Example 8 is prepared in the same manner as in Example 4, with specific reference to Example 4, except that nickel aluminum oxide is not added in Comparative Example 8, but 12 parts of titanium aluminum oxide are added, and the titanium aluminum oxide is a mixture of titanium dioxide and aluminum oxide in a mass ratio of 3:2.

[0135] Comparative Example 9

[0136] The halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture of Comparative Example 9 is prepared in the same manner as in Example 4, with specific reference to Example 4. The difference is that the composite flame retardant in Comparative Example 9 is composed of 50 parts of nano-magnesium hydroxide, 35 parts of aluminum hydroxide and 15 parts of zinc borate (selected from zinc borate HT-207 of Taixing New Materials).

[0137] Table 2 Performance test results of halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixtures

[0138]

[0139] It can be seen from the experimental results in Table 2 above that the halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture of the present invention has excellent radiation resistance, is resistant to high and low temperatures, and has high mechanical strength, combustion performance, corrosion resistance and electrical insulation.

[0140] Application Example 1

[0141] The preparation method in the above specific embodiment is used to make an anti-interference and radiation-resistant polyolefin cable. The raw materials and structure are as described in the specific embodiment, and the cable core is a wire core, the conductor 1 is a conductor, the diameter is 24.00mm, the thickness of the semiconductor layer 2 is 0.1mm, the thickness of the insulating layer 3 is 1.8mm, the thickness of the tightening layer 4 is 0.15mm, the thickness of the inner shielding layer 5 is 0.4mm, the thickness of the oxygen barrier layer 6 is 1.5mm, the thickness of the flame retardant layer 7 is 1.5mm, the thickness of the outer shielding layer 8 is 0.15mm, and the thickness of the outer sheath 9 is 3mm. Among them, the preparation methods of the ferrite-containing polyolefin composite shielding material, the ceramic flame-retardant polyolefin composite material and the halogen-free low-smoke flame-retardant and radiation-resistant polyolefin mixture refer to Example 1, Example 3 and Example 4 respectively.

[0142] Application Example 2

[0143] The preparation method in the above specific embodiment is used to make an anti-interference and radiation-resistant polyolefin cable. The raw materials and structure are as described in the specific embodiment, and the cable core is a wire core, the conductor 1 is 1, the diameter is 24.00mm, the thickness of the semiconductor layer 2 is 0.1mm, the thickness of the insulating layer 3 is 1.8mm, the thickness of the tightening layer 4 is 0.15mm, the thickness of the inner shielding layer 5 is 0.4mm, the thickness of the oxygen barrier layer 6 is 1.5mm, the thickness of the flame retardant layer 7 is 1.5mm, the thickness of the outer shielding layer 8 is 0.15mm, and the thickness of the outer sheath 9 is 3mm. Among them, the preparation methods of the ferrite-containing polyolefin composite shielding material, the ceramic flame-retardant polyolefin composite material and the halogen-free low-smoke flame-retardant and radiation-resistant polyolefin mixture refer to Example 2, Example 3 and Example 4 respectively. It is worth noting that the thickness difference of each layer in Application Example 1 and Application Example 2 is within a reasonable range.

[0144] The performance of the corrosion-resistant and flame-retardant cross-linked polyolefin cable produced in the above Application Example 1-2 was tested, and the test results are shown in Table 3.

[0145] Table 3 Cable performance test results

[0146]

[0147]

[0148] It can be seen from Application Examples 1-2 that the interference-resistant and radiation-resistant polyolefin cable and its manufacturing method of the present invention, starting from the perspective of optimizing the formulations of various cable components and semiconductor layers, flame retardant layers, outer sheaths, etc., fully utilizes the synergistic effects between various components and components, overcomes the shortcomings described in the background technology, and ensures that the combustion performance of the cable of the present invention reaches flame retardant Class A and the combustion performance grade reaches Class B1. The product has a simple structure, easy production, a wide range of applications, and low cost. It has the characteristics of good anti-interference, excellent radiation resistance, excellent flame retardancy, excellent electrical properties, good mechanical properties, and strong corrosion resistance.

[0149] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0150] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. An anti-interference and radiation-resistant polyolefin cable, comprising a cable core, a tightening layer (4), an inner shielding layer (5), an oxygen barrier layer (6), a flame retardant layer (7), an outer shielding layer (8) and an outer sheath (9), wherein the cable core is one or more wire cores, wherein the wire core comprises a conductor (1), a semiconductor layer (2) and an insulating layer (3), and wherein: The conductor (1) is extruded with a semiconductor layer (2), and the semiconductor layer (2) is extruded with an insulating layer (3); The insulating layer (3) is braided with a tightening layer (4) made of Kevlar and polyester fibers, the tightening layer (4) is wrapped with an inner shielding layer (5), the inner shielding layer (5) is extruded with an oxygen-isolating layer (6), the oxygen-isolating layer (6) is extruded with a flame-retardant layer (7), the flame-retardant layer (7) is braided with tinned copper wire as an outer shielding layer (8), and the outer shielding layer (8) is covered with an outer protective layer (9); The semiconductor layer (2) is a polyolefin composite shielding material containing ferrite; The polyolefin composite shielding material is composed of the following raw materials in parts by weight: 40-60 parts of polypropylene resin, 25-35 parts of ethylene-vinyl acetate copolymer, 15-25 parts of ethylene-butyl acrylate copolymer, 5-10 parts of PP grafted maleic anhydride, 5-15 parts of carbon black, 3-6 parts of barium ferrite, 0.1-0.5 parts of initiator DCP, 0.5-2 parts of the first silane coupling agent, 0.3-0.5 parts of antioxidant, and 1-3 parts of lubricant; The preparation method of the barium ferrite is: S1. Add appropriate proportions of ferrous nitrate, ferric nitrate and polyethylene glycol to an appropriate amount of deionized water and stir continuously until dissolved, then add ammonia water to adjust the pH value to 10-11, heat to 50-70 ° C for 2-4h, filter, wash and dry to obtain an iron oxide precursor; S2. The iron oxide precursor and barium carbonate prepared above are added to glacial acetic acid and stirred until dissolved to form a mixed solution; S3. Add an appropriate amount of dilute nitric acid to the mixed solution, stir for 5-10 minutes, then heat to 200-220 ° C for 3-5 hours, cool to room temperature, filter, and then wash with deionized water and anhydrous ethanol 2-3 times, and then vacuum dry at 80 ° C for 2-5 hours to obtain barium ferrite; The flame retardant layer (7) is a ceramic flame retardant polyolefin composite material; The outer protective layer (9) is a halogen-free, low-smoke, flame-retardant, and radiation-resistant polyolefin mixture.

2. The anti-interference and radiation-resistant polyolefin cable according to claim 1, characterized in that: The molar ratio of ferrous nitrate to ferric nitrate is (0.4-0.6):1; The molar ratio of iron to barium carbonate in the iron oxide precursor is (9-10):

1.

3. The anti-interference and radiation-resistant polyolefin cable according to claim 1, characterized in that: The ceramic flame-retardant polyolefin composite material is composed of the following raw materials in parts by weight: 30-50 parts of low-density polyethylene, 15-30 parts of ethylene-methyl acrylate copolymer, 40-60 parts of ethylene propylene diene terpolymer, 30-50 parts of aminosilane-coated wollastonite, 10-20 parts of low-melting-point glass powder, 15-25 parts of phlogopite powder, 0.2-0.4 parts of initiator DCP, 5-10 parts of lithium borate salt, 6-12 parts of halogen-free flame retardant and 1-3 parts of second silane coupling agent.

4. The anti-interference and radiation-resistant polyolefin cable according to claim 3, characterized in that: The aminosilane-coated wollastonite uses aminopropyltriethoxysilane to perform surface modification on the wollastonite, with a coating rate of ≥70%; The lithium borate salt is composed of lithium tetraborate, lithium metaborate and zinc borate in a mass ratio of 1:2:4; The halogen-free flame retardant is composed of nano magnesium hydroxide, magnesium stearate and silicone oil in a mass ratio of (0.2-0.5):1:1; The second silane coupling agent is composed of vinyltrimethoxysilane and aminopropyltriethoxysilane in a mass ratio of 3:

2.

5. The anti-interference and radiation-resistant polyolefin cable according to claim 1, characterized in that: The halogen-free, low-smoke, flame-retardant and radiation-resistant polyolefin mixture is composed of the following raw materials in parts by weight: Linear low-density polyethylene 30-50 parts, 20-40 parts of ethylene-methyl acrylate copolymer, 20-40 parts of ethylene-octene copolymer, 5-10 parts of polyimide resin, 20-40 parts of low melting point glass powder, Epoxidized soybean oil 10-20 parts, Composite flame retardant 20-40 parts, 10-15 parts of nickel aluminum oxide, Antioxidant 168 0.2-0.4 parts, Initiator DCP 0.1-0.3 parts, 20-40 parts of filler, 3-5 parts of the third silane coupling agent.

6. The interference-resistant and radiation-resistant polyolefin cable according to claim 5, characterized in that: The composite flame retardant is composed of the following raw materials in parts by mass: 40-60 parts of nano magnesium hydroxide, 10-20 parts of aluminum hydroxide and 30-40 parts of manganese borate.

7. The interference-resistant and radiation-resistant polyolefin cable according to claim 5, characterized in that: The nickel aluminum oxide is a mixture of nickel oxide and aluminum oxide in a mass ratio of 1:3; The filler is composed of calcined kaolin and phlogopite powder in a mass ratio of 1:2; The third silane coupling agent is a mixture of vinyltrimethoxysilane and 2-aminoethyl-aminopropyltrimethoxysilane in a mass ratio of 2:

3.

8. The anti-interference and radiation-resistant polyolefin cable according to claim 1, characterized in that: The insulating layer (3) is a polyolefin elastomer insulating material resistant to high temperatures of 150°C; The tightening layer (4) is a fiber interlaced structure composed of equal amounts of Kevlar and polyester fibers; The inner shielding layer (5) is an aluminum foil Mylar tape; The oxygen barrier layer (6) is a low-smoke, halogen-free, flame-retardant cable material having an oxygen index greater than or equal to 40; The outer shielding layer (8) is woven from tinned copper wires, with a braiding angle of 30-45° and a coverage rate of more than 80%.

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