A method for preparing a radiation type high temperature resistant cable

Abstract

The application discloses a preparation method of an irradiation type high-temperature-resistant cable and relates to the technical field of cables. In the application, trichloroethyl phosphate is combined with guanidine sulfamate to introduce nitrogen elements, release non-combustible gas during combustion, dilute combustible gas concentration, preliminarily realize the flame-retardant effect, and assist the formation of a porous foamed carbon layer of phosphate groups to prevent oxygen from entering and further improve the flame-retardant effect. Then, the modified flame retardant is prepared by dehydration condensation of vinyl trihydroxysilane, Si-O bonds are formed, the thermal stability of the material is significantly improved, and the flame-retardant effect is effectively improved. Then, diallyl phenyl phosphine and the modified flame retardant are used to participate in the polymerization reaction of polyethylene to form a stable three-dimensional cross-linked network structure, improve the mechanical properties of the surface of the cable, introduce phenyl groups, significantly improve the thermal stability and oxidation resistance, and make the material generate non-combustible products during combustion, so that the spread of flame is inhibited, and the flame-retardant effect is realized.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of cables, in particular to a preparation method of an irradiation type high-temperature-resistant cable. BACKGROUND

[0002] Since the 1990s, the cable industry in China has developed rapidly, and at present, the scale and output have ranked first in the world. Small and powerful cables have become an important branch of the cable industry, and the total output value accounts for about 15% of the cable industry, and are mainly applied to the fields of electronic information, automobiles and the like. In the world, China is a large country in cable production and use, but the independent innovation capability of the cable industry in China is relatively lacking, and there is still a large gap between the halogen-free flame-retardant irradiation crosslinked polyolefin cable material for cables and the same products abroad.

[0003] In recent years, in order to improve the independent research and development capability of the halogen-free flame-retardant polyolefin cable material for cables, the halogen-free flame-retardant irradiation crosslinked polyolefin cable material for cables has become one of the research hotspots, and certain research results have been achieved. Although polyvinyl chloride (PVC) containing halogen as the base of the cable material is cheap, the process is mature, and the flame-retardant performance is excellent, but it releases a large amount of hydrogen chloride gas in the combustion process, pollutes the environment, and international well-known electronic enterprises such as Apple have explicitly prohibited the use of halogen-containing materials in their products; and in order to meet the flame-retardant performance requirements, the traditional halogen-free flame-retardant cable usually adds a large amount of inorganic flame retardant such as magnesium hydroxide, aluminum hydroxide and red phosphorus in the base of the cable material, and the addition of the inorganic flame retardant will inevitably cause the serious decline of the mechanical properties and processing properties of the material, and also reduce the temperature resistance grade of the material. And the inorganic substance is only dispersed in the base material through physical action, and the molecular migration cannot be avoided, thereby affecting the long-term stability of the cable material. Therefore, it is urgent to invent a halogen-free, inorganic filler-free irradiation type high-temperature-resistant flame-retardant cable. SUMMARY

[0004] The application aims to provide an irradiation type high-temperature-resistant cable and a preparation method thereof, so as to solve the problems in the prior art.

[0005] In order to solve the above technical problems, the application provides the following technical scheme: an irradiation type high-temperature-resistant cable, which comprises, from inside to outside, an oxygen-free copper core, an irradiation crosslinked modified polyolefin insulation layer and a polyethylene outer protective layer.

[0006] Further, the irradiation crosslinked modified polyolefin insulation layer is prepared by electron beam irradiation of modified polyolefin.

[0007] Further, the electron beam of the electron beam irradiation is gamma 60 Co.

[0008] Further, the modified polyolefin is prepared by a modified flame retardant, a diallyl phenyl phosphine, and ethylene polymerization.

[0009] Further, the modified flame retardant is prepared by trichloroethyl phosphate, guanidine sulfamic acid, and vinyl trihydroxysilane.

[0010] Further, a preparation method of the irradiation type high-temperature-resistant cable comprises the following preparation steps:

[0011] (1) 16-24 parts of trichloroethyl phosphate, 8-12 parts of triethylamine, 96-144 parts of dichloromethane are uniformly mixed, 35-53 parts of guanidine sulfamic acid is added, stirred at 100 rpm for 3-4 h, 81-117 parts of deionized water is added, the organic phase is separated, concentrated at a vacuum degree of-0.08 MPa and 35℃ for 1-3 h, 48-72 parts of dimethylformamide, 32-50 parts of vinyl trihydroxysilane, and 6-14 parts of trifluoroacetic anhydride are added, heated to 110-130℃, stirred at 120 rpm for 20-40 h to obtain a reaction solution, and the reaction solution is subjected to precipitation treatment and dried at 50-60℃ for 5-9 h to obtain a modified flame retardant;

[0012] (2) Under a nitrogen atmosphere, 14-22 parts of diallyl phenyl phosphine, 5-9 parts of the modified flame retardant, 1-3 parts of a catalyst, and 70-128 parts of toluene are uniformly mixed at 80 rpm, ethylene gas is introduced until the pressure reaches 2 MPa, heated to 65-75℃, and reacted for 5-9 h, during which ethylene gas is continuously introduced to maintain the pressure unchanged, after the reaction is completed, air is connected, the solid is filtered, 113-175 parts of ethyl acetate is added and stirred at 60 rpm for 30-40 min, the filtrate is filtered, concentrated at a vacuum degree of-0.1 MPa and 40℃ for 2-4 h to obtain a modified polyolefin;

[0013] (3) Under a nitrogen atmosphere, the modified polyolefin is encapsulated and irradiated in a radiation device for 4-12 h under a certain radiation dose to obtain an irradiation cross-linked modified polyolefin; 60 Co is a radiation source, the source intensity is 3.7x10 15 Bq, and the irradiation cross-linked modified polyolefin is obtained.

[0014] (4) 57-69 parts of the irradiation cross-linked modified polyolefin, 3-5 parts of phenyl silicone oil, and 4-6 parts of diisodecyl adipate are uniformly mixed, melted and extruded at 180-190℃ to coat an oxygen-free copper core to form an insulation layer with a thickness of 0.8 mm, then 72-88 parts of polyethylene, 1-3 parts of carbon black, and 2-4 parts of montmorillonite are added, melted and extruded at 170-190℃ to coat the insulation layer to form an outer protective layer with a thickness of 2 mm, and then the temperature is lowered to 30℃ at a rate of 60℃ / min to obtain an irradiation type high-temperature-resistant cable.

[0015] Further, the precipitation process of step (1) is: 1 part of the reaction solution is added to 10 parts of deionized water, stirred at 160 rpm for 20-40 min, and the solid is taken out by filtration and washed with deionized water for 3 times.

[0016] Further, the catalyst of step (2) is one or a mixture of more of titanium catalyst, chromium catalyst, vanadium catalyst.

[0017] Further, the irradiation dose of step (3) is 12-16 MRad.

[0018] Further, the oxygen-free copper core cross-sectional area of step (4) is 6 mm 2 ; the model of the polyethylene is LDPELD165.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] The present application utilizes the combination of the chlorine group in trichloroethyl phosphate and the hydroxyl group of amino sulfamic guanidine to introduce nitrogen element, release non-combustible gases such as ammonia and nitrogen during combustion, dilute the concentration of combustible gases, and preliminarily achieve the flame-retardant effect, and the guanidine group in the compound and the hydroxyl group of vinyl trihydroxysilane are dehydrated and condensed to prepare a modified flame retardant, form Si-O bonds, and significantly improve the thermal stability of the material and effectively improve the flame-retardant effect.

[0021] Secondly, the modified polyolefin utilizes the olefin group of the diallyl phenyl phosphine and the double bond in the modified flame retardant to jointly participate in the polymerization reaction of polyethylene, form a stable three-dimensional cross-linked network structure, thereby improving the mechanical properties of the cable surface, introduce phenyl groups, significantly improve the thermal stability and oxidation resistance, and the presence of phosphorus elements makes the material decompose to produce phosphorus oxides and phosphates during combustion, react with hydrogen and free radicals to generate non-combustible products such as phosphates and phosphate salts, thereby inhibiting the spread of flames and achieving the flame-retardant effect. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0023] In order to more clearly illustrate the method provided by the present application, the following embodiments are described in detail. The test methods of each index of the irradiation type high temperature resistant cable prepared in the following embodiments are as follows:

[0024] Tensile strength and elongation at break: Cables of the same length from the example and comparative examples were tested in accordance with GB / T 2951.

[0025] 200°C thermal stability time: Take cables of the same length as the example and the comparative example, raise the temperature of the thermal aging test chamber to about 200°C, and put the cables in it. Start timing when the temperature reaches 200°C. Observe the color change and record the time required for the color to start to turn slightly yellow as the thermal stability time at 200°C.

[0026] Flame retardancy rating: Cables of the same length from the example and comparative examples were tested according to IEC 60332-3.

[0027] Example 1

[0028] (1) Mix 16 parts of trichloroethyl phosphate, 8 parts of triethylamine and 96 parts of dichloromethane evenly, add 35 parts of guanidine aminosulfonate, stir at 100 rpm for 3 h, add 81 parts of deionized water, separate the organic phase, concentrate at -0.08 MPa and 35 ℃ for 1 h, add 48 parts of dimethylformamide, 32 parts of vinyltrihydroxysilane and 6 parts of trifluoroacetic anhydride, heat to 110 ℃, stir at 120 rpm for 20 h to obtain the reaction solution, add 1 part of the reaction solution to 10 parts of deionized water, stir at 160 rpm for 20 min, filter to obtain the solid, wash 3 times with deionized water, dry at 50 ℃ for 5 h to obtain the modified flame retardant;

[0029] (2) Under a nitrogen atmosphere, 14 parts of diallylphenylphosphine, 5 parts of modified flame retardant, 1 part of titanium catalyst and 70 parts of toluene were mixed evenly at 80 rpm. Ethylene gas was introduced until the pressure was 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 keep the pressure constant. After the reaction was completed, air was introduced, the solid was filtered and 113 parts of ethyl acetate were added and stirred at 60 rpm for 30 min. The filtrate was filtered and concentrated at a vacuum of -0.1 MPa and 40 °C for 2 h to obtain modified polyolefin.

[0030] (3) Under a nitrogen atmosphere, the modified polyolefin was encapsulated and then subjected to γ-ray in an irradiation device. 60 Co is the radiation source, with a source strength of 3.7 x 10⁻⁶. 15 Bq was irradiated for 4 hours at an irradiation dose of 12MRad to obtain irradiated crosslinked modified polyolefin;

[0031] (4) Mix 57 parts of irradiated crosslinked modified polyolefin, 3 parts of phenyl silicone oil, and 4 parts of diisodecyl adipate evenly, melt and extrude at 180°C to coat an oxygen-free copper core, forming an insulating layer of 0.8 mm. The cross-sectional area of ​​the oxygen-free copper core is 6 mm². 2Subsequently, 72 parts of LDPE LD165, 1 part of carbon black, and 2 parts of montmorillonite were added, and the mixture was melted and extruded at 170°C to cover the insulation layer, forming a 2mm outer protective layer. The temperature was then reduced to 30°C at 60°C / min to obtain an irradiated high-temperature resistant cable.

[0032] Example 2

[0033] (1) Mix 20 parts of trichloroethyl phosphate, 10 parts of triethylamine and 120 parts of dichloromethane evenly, add 44 parts of guanidine aminosulfonate, stir at 100 rpm for 3.5 h, add 99 parts of deionized water, separate the organic phase, concentrate at -0.08 MPa and 35 ℃ for 2 h, add 60 parts of dimethylformamide, 41 parts of vinyltrihydroxysilane and 10 parts of trifluoroacetic anhydride, heat to 120 ℃, stir at 120 rpm for 30 h to obtain the reaction solution, add 1 part of the reaction solution to 10 parts of deionized water, stir at 160 rpm for 30 min, filter to obtain the solid, wash 3 times with deionized water, dry at 55 ℃ for 7 h to obtain the modified flame retardant;

[0034] (2) Under a nitrogen atmosphere, 18 parts of diallylphenylphosphine, 7 parts of modified flame retardant, 2 parts of chromium catalyst and 99 parts of toluene were mixed evenly at 80 rpm. Ethylene gas was introduced until the pressure was 2 MPa, the temperature was raised to 70 °C and the reaction was carried out for 7 h. During the reaction, ethylene gas was continuously introduced to keep the pressure constant. After the reaction was completed, air was introduced, the solid was filtered and 144 parts of ethyl acetate were added and stirred at 60 rpm for 35 min. The filtrate was filtered and concentrated at a vacuum of -0.1 MPa and 40 °C for 3 h to obtain modified polyolefin.

[0035] (3) Under a nitrogen atmosphere, the modified polyolefin was encapsulated and then subjected to γ-ray in an irradiation device. 60 Co is the radiation source, with a source strength of 3.7 x 10⁻⁶. 15 Bq was irradiated for 8 hours at a dose of 14MRad to obtain irradiated crosslinked modified polyolefin.

[0036] (4) Mix 63 parts of irradiated crosslinked modified polyolefin, 4 parts of phenyl silicone oil, and 5 parts of diisodecyl adipate evenly, melt and extrude at 185°C to coat an oxygen-free copper core, forming an insulating layer of 0.8 mm. The cross-sectional area of ​​the oxygen-free copper core is 6 mm². 2 Subsequently, 80 parts of LDPE LD165, 2 parts of carbon black, and 3 parts of montmorillonite were added, and the mixture was melted and extruded at 180°C to cover the insulation layer, forming a 2mm outer protective layer. The temperature was then reduced to 30°C at 60°C / min to obtain an irradiated high-temperature resistant cable.

[0037] Example 3

[0038] (1) Mix 24 parts of trichloroethyl phosphate, 12 parts of triethylamine and 144 parts of dichloromethane evenly, add 53 parts of guanidine aminosulfonate, stir at 100 rpm for 4 h, add 117 parts of deionized water, separate the organic phase, concentrate at -0.08 MPa and 35 ℃ for 3 h, add 72 parts of dimethylformamide, 50 parts of vinyltrihydroxysilane and 14 parts of trifluoroacetic anhydride, heat to 130 ℃, stir at 120 rpm for 40 h to obtain the reaction solution, add 1 part of the reaction solution to 10 parts of deionized water, stir at 160 rpm for 40 min, filter to obtain the solid, wash with deionized water 3 times, dry at 60 ℃ for 9 h to obtain the modified flame retardant;

[0039] (2) Under a nitrogen atmosphere, 22 parts of diallylphenylphosphine, 9 parts of modified flame retardant, 3 parts of vanadium catalyst and 128 parts of toluene were mixed evenly at 80 rpm. Ethylene gas was introduced until the pressure was 2 MPa, and the temperature was raised to 75°C. The reaction was carried out for 9 h. During the reaction, ethylene gas was continuously introduced to keep the pressure constant. After the reaction was completed, air was introduced, the solid was filtered, 175 parts of ethyl acetate were added and stirred at 60 rpm for 40 min, the filtrate was filtered, and the filtrate was concentrated at a vacuum of -0.1 MPa and 40°C for 4 h to obtain modified polyolefin.

[0040] (3) Under a nitrogen atmosphere, the modified polyolefin was encapsulated and then subjected to γ-ray in an irradiation device. 60 Co is the radiation source, with a source strength of 3.7 x 10⁻⁶. 15 Bq was irradiated for 12 hours at a dose of 16MRad to obtain irradiated crosslinked modified polyolefin.

[0041] (4) Mix 69 parts of irradiated crosslinked modified polyolefin, 5 parts of phenyl silicone oil, and 6 parts of diisodecyl adipate evenly, melt and extrude at 190°C to coat an oxygen-free copper core, forming an insulating layer of 0.8 mm. The cross-sectional area of ​​the oxygen-free copper core is 6 mm². 2 Subsequently, 88 parts of LDPE LD165, 3 parts of carbon black, and 4 parts of montmorillonite were added, and the mixture was melted and extruded at 190°C to cover the insulation layer, forming a 2mm outer protective layer. The temperature was then reduced to 30°C at 60°C / min to obtain an irradiated high-temperature resistant cable.

[0042] Comparative Example 1

[0043] The difference between Comparative Example 1 and Example 2 lies in step (1). Step (1) is changed to: mixing 44 parts of guanidine aminosulfonate, 60 parts of dimethylformamide, 41 parts of vinyltrihydroxysilane, and 10 parts of trifluoroacetic anhydride evenly, heating to 120°C, and stirring at 120 rpm for 30 h to obtain a reaction solution. Adding 1 part of the reaction solution to 10 parts of deionized water, stirring at 160 rpm for 30 min, filtering to obtain the solid, washing 3 times with deionized water, and drying at 55°C for 7 h to obtain the modified flame retardant. The remaining steps are the same as in Example 2.

[0044] Comparative Example 2

[0045] The difference between Comparative Example 2 and Example 2 lies in step (1). Step (1) is changed to: mixing 20 parts of trichloroethyl phosphate, 60 parts of dimethylformamide, 41 parts of vinyltrihydroxysilane, and 10 parts of trifluoroacetic anhydride evenly, heating to 120°C, and stirring at 120 rpm for 30 h to obtain a reaction solution. Adding 1 part of the reaction solution to 10 parts of deionized water, stirring at 160 rpm for 30 min, filtering to obtain the solid, washing three times with deionized water, and drying at 55°C for 7 h to obtain the modified flame retardant. The remaining steps are the same as in Example 2.

[0046] Comparative Example 3

[0047] The difference between Comparative Example 3 and Example 2 lies in step (1). Step (1) is changed to: mixing 20 parts of trichloroethyl phosphate, 10 parts of triethylamine, and 120 parts of dichloromethane evenly, adding 44 parts of guanidine aminosulfonate, stirring at 100 rpm for 3.5 h, adding 99 parts of deionized water, separating the organic phase, concentrating it at -0.08 MPa and 35°C for 2 h, and drying it at 55°C for 7 h to obtain the modified flame retardant. The remaining steps are the same as in Example 2.

[0048] Comparative Example 4

[0049] The difference between Comparative Example 4 and Example 2 lies in the different steps (2) and (4). Step (2) is changed to: Under a nitrogen atmosphere, 18 parts diallylphenylphosphine, 2 parts chromium catalyst, and 99 parts toluene are mixed evenly at 80 rpm, ethylene gas is introduced until the pressure is 2 MPa, the temperature is raised to 70°C, and the reaction is carried out for 7 h. During the reaction, ethylene gas is continuously introduced to keep the pressure constant. After the reaction is completed, air is introduced, the solid is filtered, 144 parts ethyl acetate is added and stirred at 60 rpm for 35 min, the filtrate is filtered, and the filtrate is concentrated at a vacuum of -0.1 MPa and 40°C for 3 h to obtain modified polyolefin. Step (4) is changed to: 63 parts irradiated crosslinked modified polyolefin, 7 parts modified flame retardant, 4 parts phenyl silicone oil, and 5 parts diisodecyl adipate are mixed evenly, melted and extruded at 185°C to coat an oxygen-free copper core to form an insulating layer of 0.8 mm. The cross-sectional area of ​​the oxygen-free copper core is 6 mm². 2 Subsequently, 80 parts of LDPE LD165, 2 parts of carbon black, and 3 parts of montmorillonite were added, and the mixture was melted and extruded at 180°C to coat the insulation layer, forming a 2mm outer protective layer. The temperature was then reduced 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.

[0050] Comparative Example 5

[0051] The difference between Comparative Example 5 and Example 2 lies in step (2). Step (2) is changed to: under a nitrogen atmosphere, 7 parts of modified flame retardant, 2 parts of chromium catalyst, and 99 parts of toluene are mixed evenly at 80 rpm. Ethylene gas is introduced until the pressure reaches 2 MPa, and the temperature is raised to 70°C. The reaction is carried out for 7 hours. During the reaction, ethylene gas is continuously introduced to maintain a constant pressure. After the reaction is completed, air is introduced, the solid is filtered, and 144 parts of ethyl acetate are added and stirred at 60 rpm for 35 minutes. The filtrate is filtered and concentrated at a vacuum of -0.1 MPa and 40°C for 3 hours to obtain the modified polyolefin. The remaining steps are the same as in Example 2.

[0052] Comparative Example 6

[0053] The difference between Comparative Example 6 and Example 2 is that step (1) is omitted, and step (2) is changed to: Under a nitrogen atmosphere, 18 parts diallylphenylphosphine, 7 parts vinyltrihydroxysilane, 2 parts chromium catalyst, and 99 parts toluene are mixed evenly at 80 rpm, ethylene gas is introduced until the pressure is 2 MPa, the temperature is raised to 70°C, and the reaction is carried out for 7 h. During the reaction, ethylene gas is continuously introduced to maintain a constant pressure. After the reaction is completed, air is introduced, the solid is filtered, 144 parts ethyl acetate is added, and the mixture is stirred at 60 rpm for 35 min. The filtrate is filtered and concentrated at a vacuum of -0.1 MPa and 40°C for 3 h to obtain the modified polyolefin. The remaining steps are the same as in Example 2.

[0054] Example of effect

[0055] Table 1 below presents the performance analysis results of the irradiated high-temperature resistant cables using Examples 1 to 3 and Comparative Examples 1 to 5 of the present invention.

[0056] Table 1

[0057]

[0058] A comparison of the experimental data from Examples 1, 2, and 3 with Comparative Example 1 reveals that introducing phosphate groups through trichloroethyl phosphate can form non-combustible products during combustion, thereby inhibiting flame spread and achieving a flame-retardant effect. A comparison of the experimental data from Examples 1, 2, and 3 with Comparative Example 2 reveals that the presence of guanidine aminosulfonate can release non-combustible gases such as ammonia and nitrogen during combustion, diluting the concentration of combustible gases and thus achieving flame-retardant properties. A comparison of the experimental data from Examples 1, 2, and 3 with Comparative Example 3 reveals that the addition of vinyltrihydroxysilane can dehydrate and condense with guanidine aminosulfonate to form Si-O bonds, significantly improving the thermal stability of the material and effectively improving flame retardancy. Flame retardancy; a comparison of experimental data from Examples 1, 2, 3 and Comparative Example 4 shows that incorporating modified flame retardants into the polymerization reaction can form a stable three-dimensional cross-linked network structure, improving the mechanical properties of the cable; a comparison of experimental data from Examples 1, 2, 3 and Comparative Example 5 shows that utilizing diallylphenylphosphine in the polymerization reaction of polyethylene successfully introduces phenyl groups, significantly improving thermal stability, while phosphorus further enhances the flame retardancy of the material; a comparison of experimental data from Examples 1, 2, 3 and Comparative Example 6 shows that through the reaction and combination of trichloroethyl phosphate and guanidine aminosulfonate, a porous foam carbon layer is formed during combustion, blocking oxygen from entering, thereby improving flame retardancy.

[0059] 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 implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for preparing an irradiated high-temperature resistant cable, characterized in that, The preparation steps include the following: (1) Mix 20 parts of trichloroethyl phosphate, 10 parts of triethylamine and 120 parts of dichloromethane evenly, add 44 parts of guanidine aminosulfonate, stir at 100 rpm for 3.5 h, add 99 parts of deionized water, separate the organic phase, concentrate at -0.08 MPa and 35 ℃ for 2 h, add 60 parts of dimethylformamide, 41 parts of vinyltrihydroxysilane and 10 parts of trifluoroacetic anhydride, heat to 120 ℃, stir at 120 rpm for 30 h to obtain the reaction solution, add 1 part of the reaction solution to 10 parts of deionized water, stir at 160 rpm for 30 min, filter to obtain the solid, wash with deionized water 3 times, dry at 55 ℃ for 7 h to obtain the modified flame retardant; (2) Under a nitrogen atmosphere, 18 parts of diallylphenylphosphine, 7 parts of modified flame retardant, 2 parts of chromium catalyst and 99 parts of toluene were mixed evenly at 80 rpm. Ethylene gas was introduced until the pressure was 2 MPa, and the temperature was raised to 70 °C. The reaction was carried out for 7 h. During the reaction, ethylene gas was continuously introduced to keep the pressure constant. After the reaction was completed, air was introduced, the solid was filtered, 144 parts of ethyl acetate were added and stirred at 60 rpm for 35 min. The filtrate was filtered and concentrated at a vacuum of -0.1 MPa and 40 °C for 3 h to obtain modified polyolefin. Under a nitrogen atmosphere, the modified polyolefin was encapsulated and then subjected to gamma radiation in an irradiation device. 60 Co is the radiation source, with a source strength of 3.7 x 10⁻⁶. 15 Bq was irradiated for 8 hours at a dose of 14MRad to obtain irradiated crosslinked modified polyolefin. (3) Mix 63 parts of irradiated crosslinked modified polyolefin, 4 parts of phenyl silicone oil, and 5 parts of diisodecyl adipate evenly, melt and extrude at 185°C to coat an oxygen-free copper core, forming an insulating layer of 0.8 mm. The cross-sectional area of ​​the oxygen-free copper core is 6 mm². 2 Subsequently, 80 parts of LDPE LD165, 2 parts of carbon black, and 3 parts of montmorillonite were added, and the mixture was melted and extruded at 180°C to cover the insulation layer, forming a 2mm outer protective layer. The temperature was then reduced to 30°C at 60°C / min to obtain an irradiated high-temperature resistant cable.

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