Preparation method of irradiation type high-temperature-resistant cable

Abstract

The invention discloses a preparation method of an irradiation type high-temperature-resistant cable, and relates to the technical field of cables. Trichloroethyl phosphate and guanidine sulfamate are combined, nitrogen is introduced, during combustion, non-combustible gas is released, the concentration of the combustible gas is diluted, the flame retardant effect is achieved preliminarily, phosphate groups are assisted to form a porous foamy carbon layer, oxygen is prevented from entering, and then the flame retardant effect is improved; then dehydration condensation with vinyl trihydroxysilane is performed to prepare a modified flame retardant, and Si-O bonds are formed, so that the thermal stability of the material is remarkably improved, and the flame-retardant effect is effectively improved; diallylphenylphosphine and a modified flame retardant jointly participate in a polymerization reaction of polyethylene to form a stable three-dimensional cross-linked network structure, the mechanical property of the surface of the cable is improved, meanwhile, phenyl is introduced, the thermal stability and oxidation resistance are remarkably improved, meanwhile, a phosphorus element enables the material to generate a nonflammable product during combustion, and the flame-retardant performance of the cable is improved. Therefore, flame spreading is inhibited, and the flame-retardant effect is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and in particular to a method for preparing an irradiated high-temperature resistant cable. Background Art

[0002] Since the 1990s, my country's cable industry has experienced rapid growth, currently ranking first in the world in terms of scale and output. Small yet powerful, cables have become an indispensable component of the industry, accounting for approximately 15% of the industry's total output value. These cables are primarily used in electronics, information technology, and automotive applications. While my country is a major global producer and user of cables, its cable industry lacks independent innovation capabilities. Halogen-free, flame-retardant, radiation-cross-linked polyolefin cable materials lag significantly behind similar international offerings.

[0003] In recent years, efforts to improve independent R&D capabilities for halogen-free flame-retardant polyolefin cable materials have led to a focus on irradiated cross-linked polyolefin cable materials, with considerable research success. While halogen-containing polyvinyl chloride (PVC) as a cable material matrix is ​​inexpensive, has mature manufacturing processes, and offers excellent flame retardancy, it releases significant amounts of hydrogen chloride gas during combustion, causing environmental pollution. Internationally renowned electronics companies such as Apple have explicitly banned the use of halogen-containing materials in their products. Traditional halogen-free flame-retardant cables typically incorporate large amounts of inorganic flame retardants, such as magnesium hydroxide, aluminum hydroxide, and red phosphorus, to meet flame retardancy requirements. However, the addition of inorganic flame retardants inevitably leads to a significant decrease in the material's mechanical and processing properties, as well as a reduction in its temperature resistance. Furthermore, inorganic compounds are physically dispersed within the matrix, inevitably leading to molecular migration, which can affect the long-term stability of the cable material. Therefore, there is an urgent need for a halogen-free, inorganic-free, irradiated, high-temperature flame-retardant cable. Summary of the Invention

[0004] The object of the present invention is to provide an irradiated high-temperature resistant cable and a preparation method thereof, so as to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: an irradiated high-temperature resistant cable, which includes an oxygen-free copper core, an irradiated cross-linked modified polyolefin insulation layer, and a polyethylene outer protective layer from the inside to the outside.

[0006] Furthermore, the radiation cross-linked modified polyolefin insulation layer is prepared by electron beam irradiation of modified polyolefin.

[0007] Furthermore, the electron beam ray of the electron beam irradiation is γ 60 Co.

[0008] Furthermore, the modified polyolefin is prepared by polymerizing a modified flame retardant, diallylphenylphosphine and ethylene.

[0009] Furthermore, the modified flame retardant is prepared from trichloroethyl phosphate, guanidine sulfamate, and vinyl trihydroxysilane.

[0010] Furthermore, a method for preparing an irradiated high-temperature resistant cable comprises the following steps: (1) 16-24 parts of trichloroethyl phosphate, 8-12 parts of triethylamine, and 96-144 parts of dichloromethane were mixed uniformly, 35-53 parts of guanidine sulfamate were added, and the mixture was stirred at 100 rpm for 3-4 hours. 81-117 parts of deionized water were added, and the organic phase was separated and concentrated at a vacuum degree of -0.08 MPa and 35°C for 1-3 hours. 48-72 parts of dimethylformamide, 32-50 parts of vinyltrihydroxysilane, and 6-14 parts of trifluoroacetic anhydride were added, and the mixture was heated to 110-130°C and stirred at 120 rpm for 20-40 hours to obtain a reaction solution, which was precipitated and dried at 50-60°C for 5-9 hours to obtain a modified flame retardant. (2) Under a nitrogen atmosphere, 14-22 parts of diallylphenylphosphine, 5-9 parts of a modified flame retardant, 1-3 parts of a catalyst, and 70-128 parts of toluene were mixed uniformly at 80 rpm, ethylene gas was introduced until the pressure reached 2 MPa, the temperature was raised to 65-75°C, and the reaction was carried out for 5-9 hours. During the reaction, ethylene gas was continuously introduced to maintain the pressure constant. After the reaction was completed, the air was connected, the solid was filtered, 113-175 parts of ethyl acetate was added, and the mixture was stirred at 60 rpm for 30-40 minutes. The filtrate was filtered and concentrated at a vacuum degree of -0.1 MPa and 40°C for 2-4 hours to obtain a modified polyolefin; (3) In a nitrogen atmosphere, the modified polyolefin is packaged and irradiated in a γ-ray irradiation device. 60 Co is the radiation source with a source intensity of 3.7x10 15 Bq, irradiated for 4 to 12 hours at a certain radiation dose to obtain radiation cross-linked modified polyolefin; (4) 57-69 parts of irradiated cross-linked modified polyolefin, 3-5 parts of phenyl silicone oil, and 4-6 parts of diisodecyl adipate were mixed evenly, melted and extruded at 180-190°C to coat the oxygen-free copper core to form a 0.8 mm insulation layer, and then 72-88 parts of polyethylene, 1-3 parts of carbon black, and 2-4 parts of montmorillonite were added, melted and extruded at 170-190°C to coat the insulation layer to form a 2 mm outer protective layer, and the temperature was lowered to 30°C at 60°C / min to obtain an irradiated high-temperature resistant cable.

[0011] Furthermore, the precipitation process in step (1) is as follows: adding 1 part of the reaction solution to 10 parts of deionized water, stirring at 160 rpm for 20 to 40 minutes, filtering out the solid, and washing it with deionized water three times.

[0012] Furthermore, the catalyst in step (2) is a mixture of one or more of a titanium-based catalyst, a chromium-based catalyst, and a vanadium-based catalyst.

[0013] Furthermore, the irradiation dose in step (3) is 12-16 MRad.

[0014] Furthermore, the cross-sectional area of ​​the oxygen-free copper core in step (4) is 6 mm 2 ; The model of the polyethylene is LDPELD165.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention utilizes the chlorine group in trichloroethyl phosphate to combine with the hydroxyl group of guanidine sulfamate to introduce nitrogen, thereby releasing non-combustible gases such as ammonia and nitrogen during combustion, diluting the concentration of combustible gases, and preliminarily achieving a flame retardant effect. The phosphate group is assisted to form a porous foam carbon layer to prevent oxygen from entering, thereby improving the flame retardant effect. The modified flame retardant is then prepared by dehydration condensation of the guanidine group in the composite with the hydroxyl group of vinyl trihydroxysilane to form Si-O bonds, thereby significantly improving the thermal stability of the material and effectively improving the flame retardant effect.

[0016] Secondly, the modified polyolefin utilizes the alkenyl group of diallylphenylphosphine and the double bond in the modified flame retardant to participate in the polymerization reaction of polyethylene to form a stable three-dimensional cross-linked network structure, thereby improving the mechanical properties of the cable surface. At the same time, the introduction of phenyl groups significantly improves the thermal stability and oxidation resistance. At the same time, the presence of phosphorus causes the material to decompose during combustion to produce substances such as phosphorus oxide and phosphate esters, which react with hydrogen and free radicals to produce non-combustible products such as phosphates and phosphate esters, thereby inhibiting the spread of flames and achieving a flame retardant effect. DETAILED DESCRIPTION

[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0018] In order to more clearly illustrate the method provided by the present invention, the following examples are used to describe in detail the various index testing methods of the irradiated high temperature resistant cables prepared in the following examples. Tensile strength and elongation at break: cables of the embodiment and comparative example of the same length were tested in accordance with GB / T 2951.

[0019] Thermal stabilization time at 200°C: Take cables of the same length as those in the embodiment and comparative example, raise the temperature of the thermal aging test chamber to approximately 200°C, and quickly place the cables therein. Start timing when the temperature reaches approximately 200°C, and observe the color change. The time required for the color to begin to turn slightly yellow is recorded as the thermal stabilization time at 200°C.

[0020] Flame retardant level: cables of the embodiment and comparative example of the same length were tested in accordance with IEC 60332-3.

[0021] Example 1 (1) 16 parts of trichloroethyl phosphate, 8 parts of triethylamine, and 96 parts of dichloromethane were mixed uniformly, 35 parts of guanidine sulfamate were added, and the mixture was stirred at 100 rpm for 3 h. 81 parts of deionized water were added, and the organic phase was separated and concentrated at a vacuum degree of -0.08 MPa and 35°C for 1 h. 48 parts of dimethylformamide, 32 parts of vinyltrihydroxysilane, and 6 parts of trifluoroacetic anhydride were added. The mixture was heated to 110°C and stirred at 120 rpm for 20 h to obtain a reaction solution. 1 part of the reaction solution was added to 10 parts of deionized water, and the mixture was stirred at 160 rpm for 20 min. The solid was filtered and washed three times with deionized water. The solid was dried at 50°C for 5 h to obtain a modified flame retardant. (2) Under a nitrogen atmosphere, 14 parts of diallylphenylphosphine, 5 parts of a modified flame retardant, 1 part of a titanium catalyst, and 70 parts of toluene were mixed uniformly at 80 rpm, ethylene gas was introduced until the pressure reached 2 MPa, the temperature was raised to 65°C, and the reaction was carried out for 5 h. During the reaction, ethylene gas was continuously introduced to maintain the pressure constant. After the reaction was completed, the air was connected, the solid was filtered, 113 parts of ethyl acetate was added, and the mixture was stirred at 60 rpm for 30 min. The filtrate was filtered and concentrated at a vacuum degree of -0.1 MPa and 40°C for 2 h to obtain a modified polyolefin; (3) In a nitrogen atmosphere, the modified polyolefin is packaged and irradiated in a γ-ray irradiation device. 60 Co is the radiation source with a source intensity of 3.7x10 15 Bq, irradiated at a dose of 12 MRad for 4 h to obtain radiation-crosslinked modified polyolefin; (4) 57 parts of irradiated cross-linked modified polyolefin, 3 parts of phenyl silicone oil, and 4 parts of diisodecyl adipate were mixed evenly, melted and extruded at 180°C to coat the oxygen-free copper core to form a 0.8 mm insulation layer. The cross-sectional area of ​​the oxygen-free copper core was 6 mm. 2 ; Then add 72 parts of LDPE LD165, 1 part of carbon black, and 2 parts of montmorillonite, melt and extrude the insulation layer at 170°C to form a 2mm outer protective layer, and cool it to 30°C at 60°C / min to obtain an irradiated high-temperature resistant cable.

[0022] Example 2 (1) 20 parts of trichloroethyl phosphate, 10 parts of triethylamine, 120 parts of dichloromethane were mixed uniformly, 44 parts of guanidine sulfamate was added, stirred at 100 rpm for 3.5 h, 99 parts of deionized water was added, the organic phase was separated, concentrated at a vacuum degree of -0.08 MPa and 35℃ for 2 h, 60 parts of dimethylformamide, 41 parts of vinyltrihydroxysilane, 10 parts of trifluoroacetic anhydride were added, and the temperature was raised to 120℃, and stirred at 120 rpm for 30 h to obtain a reaction solution, 1 part of the reaction solution was added to 10 parts of deionized water, stirred at 160 rpm for 30 min, and the solid was filtered and washed with deionized water for 3 times, and dried at 55℃ for 7 h to obtain a modified flame retardant; (2) Under a nitrogen atmosphere, 18 parts of diallyl phenyl phosphine, 7 parts of modified flame retardant, 2 parts of chromium catalyst, 99 parts of toluene were uniformly mixed, ethylene gas was introduced to a pressure of 2 MPa, the temperature was raised to 70℃, and reacted for 7 h. During the reaction, ethylene gas was continuously introduced to maintain the pressure unchanged. After the reaction was completed, air was connected, the solid was filtered, 144 parts of ethyl acetate was added and stirred at 60 rpm for 35 min, the filtrate was filtered, concentrated at a vacuum degree of -0.1 MPa and 40℃ for 3 h to obtain a modified polyolefin; (3) Under a nitrogen atmosphere, the modified polyolefin was packaged and irradiated in a radiation device with γ 60 Co as the radiation source, the source intensity was 3.7x10 15 Bq, and irradiated for 8 h at an irradiation dose of 14 MRad to obtain an irradiated cross-linked modified polyolefin; (4) 63 parts of the irradiated cross-linked modified polyolefin, 4 parts of phenyl silicone oil, and 5 parts of diisodecyl adipate were uniformly mixed, melted and extruded at 185℃ to coat an oxygen-free copper core to form an insulation layer of 0.8 mm, the oxygen-free copper core had a cross-sectional area of 6 mm 2 ; then 80 parts of LDPE LD165, 2 parts of carbon black, and 3 parts of montmorillonite were added, melted and extruded at 180℃ to coat the insulation layer to form an outer protective layer of 2 mm, and the temperature was reduced to 30℃ at a rate of 60℃ / min to obtain an irradiated high-temperature resistant cable.

[0023] Example 3 (1) 24 parts of trichloroethyl phosphate, 12 parts of triethylamine, 144 parts of dichloromethane were mixed uniformly, 53 parts of guanidine sulfamate was added, stirred at 100 rpm for 4 h, 117 parts of deionized water was added, the organic phase was separated, concentrated at a vacuum degree of -0.08 MPa and 35℃ for 3 h, 72 parts of dimethylformamide, 50 parts of vinyltrihydroxysilane, 14 parts of trifluoroacetic anhydride were added, the temperature was raised to 130℃, and stirred at 120 rpm for 40 h to obtain a reaction solution, 1 part of the reaction solution was added to 10 parts of deionized water, stirred at 160 rpm for 40 min, the solid was filtered and washed with deionized water for 3 times, and dried at 60℃ for 9 h to obtain a modified flame retardant; (2) Under nitrogen atmosphere, 22 parts of diallyl phenyl phosphine, 9 parts of modified flame retardant, 3 parts of vanadium catalyst, 128 parts of toluene were mixed uniformly, ethylene gas was introduced until the pressure reached 2 MPa, and the temperature was raised to 75°C. The reaction was carried out for 9 h, and ethylene gas was continuously introduced to maintain the pressure during the reaction. After the reaction was completed, air was connected, and the solid was filtered. 175 parts of ethyl acetate were added and stirred at 60 rpm for 40 min. The filtrate was filtered, concentrated at a vacuum degree of -0.1 MPa and a temperature of 40°C for 4 h, and the modified polyolefin was obtained. (3) Under nitrogen atmosphere, the modified polyolefin was packaged and irradiated in a radiation device with γ 60 Co as the radiation source, with a source strength of 3.7x10 15 Bq, for 12 h at an irradiation dose of 16 MRad to obtain the irradiated cross-linked modified polyolefin. (4) 69 parts of the irradiated cross-linked modified polyolefin, 5 parts of phenyl silicone oil, and 6 parts of diisodecyl adipate were mixed uniformly, melted and extruded at 190°C to coat an oxygen-free copper core to form an insulation layer of 0.8 mm. The oxygen-free copper core had a cross-sectional area of 6 mm 2 ; then 88 parts of LDPE LD165, 3 parts of carbon black, and 4 parts of montmorillonite were added, melted and extruded at 190°C to coat the insulation layer to form an outer protective layer of 2 mm. The temperature was reduced to 30°C at a rate of 60°C / min to obtain the irradiated high-temperature-resistant cable.

[0024] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is in step (1), which is changed to: 44 parts of guanidine sulfamate, 60 parts of dimethyl formamide, 41 parts of vinyl trihydroxysilane, and 10 parts of trifluoroacetic anhydride were mixed uniformly, and the temperature was raised to 120°C. Stirring was carried out at 120 rpm for 30 h to obtain a reaction solution. 1 part of the reaction solution was added to 10 parts of deionized water, and stirring was carried out at 160 rpm for 30 min. The solid was filtered, washed with deionized water for 3 times, and dried at 55°C for 7 h to obtain the modified flame retardant. The remaining steps are the same as those of Example 2.

[0025] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is in step (1), which is changed to: 20 parts of trichloroethyl phosphate, 60 parts of dimethyl formamide, 41 parts of vinyl trihydroxysilane, and 10 parts of trifluoroacetic anhydride were mixed uniformly, and the temperature was raised to 120°C. Stirring was carried out at 120 rpm for 30 h to obtain a reaction solution. 1 part of the reaction solution was added to 10 parts of deionized water, and stirring was carried out at 160 rpm for 30 min. The solid was filtered, washed with deionized water for 3 times, and dried at 55°C for 7 h to obtain the modified flame retardant. The remaining steps are the same as those of Example 2.

[0026] Comparative Example 3 The difference between Comparative Example 3 and Example 2 lies in step (1). Step (1) is modified as follows: 20 parts of trichloroethyl phosphate, 10 parts of triethylamine, and 120 parts of dichloromethane are mixed uniformly, 44 parts of guanidine sulfamate are added, and the mixture is stirred at 100 rpm for 3.5 hours. 99 parts of deionized water are added, and the organic phase is separated and concentrated at a vacuum degree of -0.08 MPa and 35°C for 2 hours, and then dried at 55°C for 7 hours to obtain a modified flame retardant. The remaining steps are the same as those in Example 2.

[0027] Comparative Example 4 The difference between Comparative Example 4 and Example 2 lies in the difference between steps (2) and (4). Step (2) is changed to: in a nitrogen atmosphere, 18 parts of diallylphenylphosphine, 2 parts of a chromium catalyst, and 99 parts of toluene are mixed uniformly at 80 rpm, ethylene gas is introduced until the pressure reaches 2 MPa, the temperature is raised to 70°C, and the reaction is carried out for 7 hours. During the reaction, ethylene gas is continuously introduced to maintain the pressure constant. After the reaction is completed, the air is connected, the solid is filtered out, 144 parts of ethyl acetate are added, and the mixture is stirred at 60 rpm for 35 minutes. The filtrate is filtered out and concentrated at a vacuum degree of -0.1 MPa and 40°C for 3 hours to obtain a modified polyolefin; step (4) is changed to: 63 parts of irradiated cross-linked modified polyolefin, 7 parts of a modified flame retardant, 4 parts of phenyl silicone oil, and 5 parts of diisodecyl adipate are mixed uniformly, melt-extruded at 185°C to coat an oxygen-free copper core to form a 0.8 mm insulating layer. The cross-sectional area of ​​the oxygen-free copper core is 6 mm 2 80 parts of LDPE LD165, 2 parts of carbon black, and 3 parts of montmorillonite were then added and melt-extruded at 180°C to form a 2 mm outer protective layer. The temperature was then lowered to 30°C at a rate of 60°C / min to obtain an irradiated high-temperature resistant cable. The remaining steps were the same as in Example 2.

[0028] Comparative Example 5 The difference between Comparative Example 5 and Example 2 lies in step (2). Step (2) is modified as follows: Under a nitrogen atmosphere, 7 parts of a modified flame retardant, 2 parts of a chromium catalyst, and 99 parts of toluene are mixed uniformly at 80 rpm, ethylene gas is introduced until the pressure reaches 2 MPa, the temperature is raised to 70°C, and the reaction is carried out for 7 hours. During the reaction, ethylene gas is continuously introduced to maintain the pressure constant. After the reaction is completed, air is connected, the solid is filtered, 144 parts of ethyl acetate is added, and the mixture is stirred at 60 rpm for 35 minutes. The filtrate is filtered, and the mixture is concentrated at a vacuum degree of -0.1 MPa and 40°C for 3 hours to obtain a modified polyolefin. The remaining steps are the same as those in Example 2.

[0029] Comparative Example 6 Comparative Example 6 differs from Example 2 in that step (1) is omitted and step (2) is modified as follows: Under a nitrogen atmosphere, 18 parts of diallylphenylphosphine, 7 parts of vinyltrihydroxysilane, 2 parts of a chromium-based catalyst, and 99 parts of toluene are mixed uniformly at 80 rpm, ethylene gas is introduced until the pressure reaches 2 MPa, the temperature is raised to 70°C, and the reaction is carried out for 7 hours. During the reaction, ethylene gas is continuously introduced to maintain the pressure constant. After the reaction is completed, air is released, the solid is filtered, 144 parts of ethyl acetate is added, and the mixture is stirred at 60 rpm for 35 minutes. The filtrate is filtered, and the mixture is concentrated at a vacuum degree of -0.1 MPa and 40°C for 3 hours to obtain a modified polyolefin. The remaining steps are the same as those in Example 2.

[0030] Effect Examples Table 1 below shows the performance analysis results of the irradiated high temperature resistant cables using Examples 1 to 3 of the present invention and Comparative Examples 1 to 5.

[0031] Table 1 From the comparison of the experimental data of Examples 1, 2, and 3 with those of Comparative Example 1, it can be found that the introduction of phosphate groups by trichloroethyl phosphate can form incombustible products during combustion, thereby inhibiting the spread of flame and achieving a flame retardant effect; from the comparison of the experimental data of Examples 1, 2, and 3 with those of Comparative Example 2, it can be found that the presence of guanidine sulfamate can release non-combustible gases such as ammonia and nitrogen during combustion and heat, dilute the concentration of combustible gases, thereby achieving flame retardant properties; from the comparison of the experimental data of Examples 1, 2, and 3 with those of Comparative Example 3, it can be found that the addition of vinyl trihydroxy silane can dehydrate and condense with guanidine sulfamate to form Si-O bonds, significantly improving the thermal stability of the material and effectively improving the flame retardant performance. Flame retardant effect; from the comparison of the experimental data of Examples 1, 2, and 3 with Comparative Example 4, it can be found that the modified flame retardant is involved in the polymerization reaction to form a stable three-dimensional cross-linked network structure, thereby improving the mechanical properties of the cable; from the comparison of the experimental data of Examples 1, 2, and 3 with Comparative Example 5, it can be found that diallylphenylphosphine is used to participate in the polymerization reaction of polyethylene, and phenyl groups are successfully introduced, which significantly improves the thermal stability. At the same time, the phosphorus element further improves the flame retardancy of the material; from the comparison of the experimental data of Examples 1, 2, and 3 with Comparative Example 6, it can be found that trichloroethyl phosphate and guanidine sulfamate are reacted and combined to form a porous foam carbon layer during combustion, which blocks the entry of oxygen, thereby improving the flame retardancy.

[0032] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed therein. Any reference in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A method for preparing an irradiated high-temperature resistant cable, characterized in that: The method comprises the following preparation steps: (1) 20 parts of trichloroethyl phosphate, 10 parts of triethylamine, and 120 parts of dichloromethane were mixed evenly, 44 parts of guanidine sulfamate were added, and the mixture was stirred at 100 rpm for 3.5 h. 99 parts of deionized water were added, and the organic phase was separated and concentrated at a vacuum degree of -0.08 MPa and 35°C for 2 h. 60 parts of dimethylformamide, 41 parts of vinyltrihydroxysilane, and 10 parts of trifluoroacetic anhydride were added. The mixture was heated to 120°C and stirred at 120 rpm for 30 h to obtain a reaction solution. 1 part of the reaction solution was added to 10 parts of deionized water, and the mixture was stirred at 160 rpm for 30 min. The solid was filtered and washed with deionized water 3 times. The solid was dried at 55°C for 7 h to obtain a modified flame retardant. (2) Under nitrogen atmosphere, 18 parts of diallylphenylphosphine, 7 parts of modified flame retardant, 2 parts of chromium catalyst, and 99 parts of toluene were mixed uniformly at 80 rpm, ethylene gas was introduced until the pressure reached 2 MPa, the temperature was raised to 70°C, and the reaction was carried out for 7 hours. During the reaction, ethylene gas was continuously introduced to maintain the pressure constant. After the reaction was completed, the air was connected, the solid was filtered, 144 parts of ethyl acetate was added, and the mixture was stirred at 60 rpm for 35 minutes. The filtrate was filtered and concentrated at a vacuum degree of -0.1 MPa and 40°C for 3 hours to obtain modified polyolefin; In a nitrogen atmosphere, the modified polyolefin was packaged and irradiated in a γ 60 Co is the radiation source with a source intensity of 3.7x10 15 Bq, irradiated at a dose of 14 MRad for 8 h to obtain radiation-crosslinked modified polyolefin; (3) 63 parts of irradiated cross-linked modified polyolefin, 4 parts of phenyl silicone oil, and 5 parts of diisodecyl adipate were mixed evenly, melted and extruded at 185°C to coat the oxygen-free copper core to form a 0.8 mm insulation layer. The cross-sectional area of ​​the oxygen-free copper core was 6 mm. 2 ; Then add 80 parts of LDPE LD165, 2 parts of carbon black, and 3 parts of montmorillonite, melt and extrude the insulation layer at 180°C to form a 2mm outer protective layer, and cool it to 30°C at 60°C / min to obtain an irradiated high-temperature resistant cable.

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