High-strength tear-resistant halogen-free flame-retardant insulating material and preparation method thereof

Abstract

This invention relates to the field of insulation materials technology, specifically to a high-strength, tear-resistant, halogen-free, flame-retardant insulating material and its preparation method. The high-strength, tear-resistant, halogen-free, flame-retardant insulating material comprises the following components by weight: 70-90 parts EPDM rubber, 5-15 parts thermoplastic elastomer, 15-25 parts medium-density polyethylene, 10-20 parts ethylene-vinyl acetate copolymer, 3-5 parts triallyl isocyanate, 2-4 parts sulfur, 1-3 parts polyethylene wax, 3-5 parts zinc oxide, 1-3 parts antioxidant, 30-50 parts aluminum hydroxide, 20-40 parts modified silica, 0.2-0.5 parts ultraviolet absorber, 1-3 parts accelerator, and 2-4 parts silicone masterbatch. The high-strength, tear-resistant, halogen-free, flame-retardant insulating material prepared by this invention exhibits excellent tensile and tear resistance and flame-retardant properties, thereby extending its service life.

Description

Technical Field

[0001] This invention relates to the field of insulating materials technology, specifically to a high-strength, tear-resistant, halogen-free, flame-retardant insulating material and its preparation method. Background Technology

[0002] With the rapid development of electronic products, the performance requirements for their materials are increasing, especially for insulation materials. High-strength, tear-resistant, halogen-free flame-retardant insulation materials are widely used in electrical, electronic, and power equipment because they not only have excellent insulation properties but also effectively prevent fires, ensuring the safety and stability of equipment. The application of halogen-free flame-retardant insulation materials can avoid the release of harmful gases and toxic substances during the combustion of halogenated substances, meeting increasingly stringent environmental regulations and market demands.

[0003] However, existing technologies still present some specific problems in the preparation and application of high-strength, tear-resistant, halogen-free flame-retardant insulation materials: Inhomogeneous material properties: During the preparation of existing halogen-free flame-retardant materials, the lack of strict formulation and process control often leads to significant differences in the physical and flame-retardant properties of the materials, affecting the reliability of the final product. Insufficient thermal stability: Many halogen-free flame-retardant insulation materials are prone to degradation at high temperatures, resulting in a decline in material performance and limiting their application in high-temperature environments. Poor environmental adaptability: Some halogen-free flame-retardant materials perform poorly in extreme environments such as humidity and high temperatures, limiting their use in certain special application areas.

[0004] Therefore, we propose a high-strength, tear-resistant, halogen-free flame-retardant insulating material and its preparation method. Summary of the Invention

[0005] The purpose of this invention is to provide a high-strength, tear-resistant, halogen-free, flame-retardant insulating material and its preparation method, so as to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a high-strength, tear-resistant, halogen-free, flame-retardant insulating material includes the following steps: Ethylene propylene diene monomer (EPDM), thermoplastic elastomer, medium-density polyethylene (MDPE), and ethylene-vinyl acetate copolymer are added to a Banbury mixer and mixed at 95-105°C for 2-3 minutes. Aluminum hydroxide, modified silica, polyethylene wax, silicone masterbatch, zinc oxide, antioxidant, and UV absorber are then added and mixed at 160-170°C for 15-25 minutes. The mixture is then discharged to obtain a rubber compound. The rubber compound is then mixed evenly with triallyl isocyanate, sulfur, and an accelerator, and subjected to open milling to obtain a compound. The compound is then subjected to crosslinking via electron accelerator irradiation to obtain a high-strength, tear-resistant, halogen-free, flame-retardant insulating material.

[0007] A more optimized solution is that the high-strength tear-resistant halogen-free flame-retardant insulating material comprises the following weight components: 70-90 parts of EPDM rubber, 5-15 parts of thermoplastic elastomer, 15-25 parts of medium-density polyethylene, 10-20 parts of ethylene-vinyl acetate copolymer, 3-5 parts of triallyl isocyanate, 2-4 parts of sulfur, 1-3 parts of polyethylene wax, 3-5 parts of zinc oxide, 1-3 parts of antioxidant, 30-50 parts of aluminum hydroxide, 20-40 parts of modified silica, 0.2-0.5 parts of ultraviolet absorber, 1-3 parts of accelerator, and 2-4 parts of silicone masterbatch.

[0008] In a more optimized embodiment, the thermoplastic elastomer is an ethylene-propylene copolymer.

[0009] A more optimized approach is to prepare the modified silica as follows: Step S1: Disperse silica ultrasonically in a mixed solution of anhydrous ethanol and deionized water, add vinyltrimethoxysilane and mix well, react at 70-80℃ for 3-5 hours, and obtain vinyl silica after centrifugation, washing and drying. Step S2: Mix vinyl silica, flame retardant and photoinitiator evenly, and react with ultraviolet light to obtain modified silica.

[0010] In a more optimized scheme, in step S1, the mass ratio of silica, anhydrous ethanol, deionized water and vinyltrimethoxysilane is 1:(15-20):(3-5):(1-3).

[0011] In a more optimized scheme, in step S2, the mass ratio of vinyl silica, flame retardant and photoinitiator is 1:(1-3):(0.03-0.05).

[0012] In a more optimized scheme, the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone, and the ultraviolet irradiation process conditions are: irradiation wavelength 360-400 nm, irradiation time 30-60 min, and irradiation intensity 20-35 mW / cm². 2 .

[0013] A more optimized approach is to prepare the flame retardant as follows: Step 1: Mix L-cysteine, 3-(2,3-epoxypropoxy)propyltrimethoxysilane and ethanol evenly, react at 30-50℃ for 3-5 hours, and then distill under reduced pressure to obtain modified L-cysteine. Step 2: Mix melamine and pyridine, heat to 40-50℃, stir until melamine is completely dissolved, introduce nitrogen gas, add modified L-cysteine ​​and dicyclohexylcarbodiimide and mix evenly, heat to 60-70℃, keep the temperature for 2-4 hours, filter, remove solvent by vacuum distillation, and dry under vacuum to obtain a mercapto-containing compound. Step 3: Under nitrogen protection, mix the mercapto compound, 2-thiophene formaldehyde and anhydrous ethanol evenly, react at 60-70℃ for 6-8 hours, raise the temperature to 80-90℃, add DOPO, continue the reaction for 10-12 hours, cool to room temperature, filter, wash and dry to obtain the flame retardant.

[0014] In a more optimized scheme, in step one, the mass ratio of L-cysteine, 3-(2,3-epoxypropoxy)propyltrimethoxysilane and ethanol is 1:(2.0-2.2):(4-6).

[0015] In a more optimized scheme, in step two, the mass ratio of melamine, pyridine, modified L-cysteine ​​and dicyclohexylcarbodiimide is 1:(10-12):(2.8-3.2):(1.0-1.5).

[0016] In a more optimized scheme, in step three, the mass ratio of the mercapto compound, 2-thiophenecarboxaldehyde, and anhydrous ethanol is 1:(3-5):(10-12).

[0017] In a more optimized approach, in step three, the amount of DOPO used is 2-4 times the total weight of the mercapto-containing compounds.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention discloses a high-strength, tear-resistant, halogen-free flame-retardant insulating material and its preparation method. The method involves a ring-opening reaction between the amino group of L-cysteine ​​and the epoxy group of 3-(2,3-epoxypropoxy)propyltrimethoxysilane to obtain modified L-cysteine. Then, the carboxyl group of the modified L-cysteine ​​undergoes an amidation reaction with the amino group of melamine to synthesize an intermediate compound containing active thiol groups, i.e., a thiol-containing compound. Using the thiol-containing compound, 2-thiophene formaldehyde, and melamine as raw materials, a one-pot synthesis is performed to create an N / S / P / Si intumescent flame-retardant material containing both a triazine structure and thiol groups. The triazine structure exhibits high rigidity and stability, enhancing the material's thermal stability and enabling the formation of a char layer at high temperatures, further improving flame-retardant performance. The introduced active thiol groups provide sites for quasi-click chemical reactions, facilitating cross-linking or modification with other functional groups, thereby enhancing the material's chemical stability.

[0019] On the other hand, this invention utilizes vinyltrimethoxysilane to perform surface modification treatment on silica, which modifies the surface of magnesium hydroxide with organosilicon molecular chains to obtain vinyl silica. This modification makes vinyl silica and flame retardant have the same organosilicon monomer structure, thereby improving their affinity and enhancing their compatibility with the resin matrix. At the same time, the thiol groups in the flame retardant can undergo a thiol-olefin click reaction with vinyl silica to form a stable chemical bond, which not only promotes the uniform dispersion of the flame retardant and silica in the matrix, but also enables them to exert excellent synergistic flame retardant effect and mechanical reinforcement, thereby comprehensively improving the flame retardant safety, tear resistance and mechanical strength of the insulation material.

[0020] 2. This invention discloses a high-strength, tear-resistant, halogen-free, flame-retardant insulating material and its preparation method. The material is compounded with ethylene propylene diene monomer (EPDM) rubber, thermoplastic elastomer, medium-density polyethylene (MDPE), and ethylene-vinyl acetate copolymer. This compounding process helps improve the material's elasticity and tensile strength, thereby enhancing its tear resistance. It is less prone to tearing under external forces, extending its service life. Furthermore, the introduction of electron beam irradiation crosslinking forms a strong crosslinked network structure within the material. This structure significantly improves the material's heat resistance, tear resistance, and chemical stability, enabling it to maintain good performance even at high temperatures. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Unless otherwise specified, all quantities below are by weight. It should be noted that there are no special restrictions on the suppliers of any of the raw materials involved in this invention. Exemplary examples include (in this embodiment): EPDM 3092PM (Sinopec Mitsui EPDM); thermoplastic elastomer: ethylene-propylene copolymer, model V11274, purchased from Shanghai Yuanye Biotechnology Co., Ltd.; medium-density polyethylene: Dow medium-density polyethylene 8818 YW; ethylene-vinyl acetate copolymer: DuPont, USA, model 40L-03; aluminum hydroxide: Albemarle flame retardant MARTINAL ON-904; silica: Wacker V15 (Germany); polyethylene wax: Honeywell polyethylene wax AC-6; silicone masterbatch: Dow Corning MB50-002 (USA); zinc oxide: item number 01, purchased from Henan Shengkun Chemical Products Co., Ltd.; ultraviolet absorber: model UV-329; antioxidant: antioxidant 1010; accelerator: accelerator CZ.

[0023] Example 1: A method for preparing a high-strength, tear-resistant, halogen-free, flame-retardant insulating material, comprising the following processes: 70 parts of EPDM rubber, 5 parts of thermoplastic elastomer, 15 parts of medium-density polyethylene, and 10 parts of ethylene-vinyl acetate copolymer were added to a mixer and mixed at 95°C for 2 minutes. Then, 30 parts of aluminum hydroxide, 20 parts of modified silica, 1 part of polyethylene wax, 2 parts of silicone masterbatch, 3 parts of zinc oxide, 1 part of antioxidant, and 0.2 parts of UV absorber were added and mixed at 160°C for 15 minutes. The mixture was then discharged to obtain a rubber compound. The rubber compound was mixed evenly with 3 parts of triallyl isocyanate, 2 parts of sulfur, and 1 part of accelerator and then subjected to open milling to obtain a compound. The compound was then subjected to crosslinking by irradiation using an electron accelerator with an electron beam energy of 1.5 MeV and an irradiation dose of 200 kGy to obtain a high-strength, tear-resistant, halogen-free, flame-retardant insulating material. The preparation method of modified silica is as follows: Step S1: Disperse 20 parts of silica ultrasonically in a mixed solution of 300 parts of anhydrous ethanol and 60 parts of deionized water, add 20 parts of vinyltrimethoxysilane and mix well, react at 70°C for 3 hours, and obtain vinyl silica after centrifugation, washing and drying. Step S2: Mix 20 parts vinyl silica, 20 parts flame retardant, and 0.6 parts 2-hydroxy-2-methyl-1-phenyl-1-propanone evenly. After ultraviolet irradiation, the mixture is irradiated at a wavelength of 380 nm for 40 min at an intensity of 25 mW / cm². 2 Modified silica was obtained; The preparation method of flame retardant is as follows: Step 1: Mix 14 parts L-cysteine, 28 parts 3-(2,3-epoxypropoxy)propyltrimethoxysilane and 56 parts ethanol evenly, react at 30°C for 3 hours, and distill under reduced pressure to obtain modified L-cysteine. Step 2: Mix 5 parts melamine and 50 parts pyridine, heat to 40°C, stir until melamine is completely dissolved, introduce nitrogen gas, add 14 parts modified L-cysteine ​​and 5 parts dicyclohexylcarbodiimide and mix evenly, heat to 60°C, keep the temperature for 2 hours, filter, remove solvent by vacuum distillation, and vacuum dry to obtain a mercapto-containing compound. Step 3: Under nitrogen protection, mix 5 parts of mercapto-containing compound, 15 parts of 2-thiophenecaraldehyde and 50 parts of anhydrous ethanol evenly, react at 60°C for 6 hours, raise the temperature to 80°C, add 10 parts of DOPO, continue the reaction for 10 hours, cool to room temperature, filter, wash and dry to obtain flame retardant.

[0024] Example 2: A method for preparing a high-strength, tear-resistant, halogen-free, flame-retardant insulating material, comprising the following processes: 80 parts of EPDM rubber, 10 parts of thermoplastic elastomer, 20 parts of medium-density polyethylene, and 15 parts of ethylene-vinyl acetate copolymer were added to a mixer and mixed at 100°C for 2.5 min. Then, 40 parts of aluminum hydroxide, 30 parts of modified silica, 1 part of polyethylene wax, 3 parts of silicone masterbatch, 4 parts of zinc oxide, 2 parts of antioxidant, and 0.4 parts of UV absorber were added and mixed at 165°C for 20 min. The mixture was then discharged to obtain a rubber compound. The rubber compound was mixed evenly with 4 parts of triallyl isocyanate, 3 parts of sulfur, and 2 parts of accelerator and then subjected to open milling to obtain a compound. The compound was then subjected to crosslinking by irradiation using an electron accelerator with an electron beam energy of 2 MeV and an irradiation dose of 230 kGy to obtain a high-strength, tear-resistant, halogen-free, flame-retardant insulating material. The preparation method of modified silica is as follows: Step S1: Disperse 30 parts of silica ultrasonically in a mixed solution of 540 parts of anhydrous ethanol and 120 parts of deionized water, add 60 parts of vinyltrimethoxysilane and mix well, react at 75°C for 4 hours, and obtain vinyl silica after centrifugation, washing and drying. Step S2: Mix 30 parts of vinyl silica, 60 parts of flame retardant, and 1.2 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone evenly. After ultraviolet irradiation, the mixture is irradiated at a wavelength of 360 nm for 30 min at an intensity of 35 mW / cm². 2 Modified silica was obtained; The preparation method of flame retardant is as follows: Step 1: Mix 36 parts of L-cysteine, 75 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and 180 parts of ethanol evenly, react at 40℃ for 4 hours, and distill under reduced pressure to obtain modified L-cysteine. Step 2: Mix 12 parts of melamine and 130 parts of pyridine, heat to 45°C, stir until the melamine is completely dissolved, introduce nitrogen gas, add 36 parts of modified L-cysteine ​​and 15 parts of dicyclohexylcarbodiimide and mix evenly, heat to 65°C, keep the reaction at this temperature for 2 hours, filter, remove the solvent by vacuum distillation, and dry under vacuum to obtain a mercapto-containing compound; Step 3: Under nitrogen protection, 12 parts of mercapto-containing compound, 48 parts of 2-thiophene formaldehyde and 130 parts of anhydrous ethanol are mixed evenly and reacted at 65°C for 7 hours. The temperature is then raised to 85°C, 36 parts of DOPO are added, and the reaction continues for 11 hours. After cooling to room temperature, the mixture is filtered, washed and dried to obtain the flame retardant.

[0025] Example 3: A method for preparing a high-strength, tear-resistant, halogen-free, flame-retardant insulating material, comprising the following processes: 90 parts of EPDM rubber, 15 parts of thermoplastic elastomer, 25 parts of medium-density polyethylene, and 20 parts of ethylene-vinyl acetate copolymer were added to a mixer and mixed at 105°C for 3 minutes. Then, 50 parts of aluminum hydroxide, 40 parts of modified silica, 3 parts of polyethylene wax, 4 parts of silicone masterbatch, 5 parts of zinc oxide, 3 parts of antioxidant, and 0.5 parts of UV absorber were added and mixed at 170°C for 25 minutes. The mixture was then discharged to obtain a rubber compound. The rubber compound was then mixed evenly with 5 parts of triallyl isocyanate, 4 parts of sulfur, and 3 parts of accelerator and subjected to open milling to obtain a compound. The compound was then subjected to crosslinking by irradiation using an electron accelerator with an electron beam energy of 3 MeV and an irradiation dose of 250 kGy to obtain a high-strength, tear-resistant, halogen-free, flame-retardant insulating material. The preparation method of modified silica is as follows: Step S1: Disperse 40 parts of silica ultrasonically in a mixed solution of 800 parts of anhydrous ethanol and 200 parts of deionized water, add 120 parts of vinyltrimethoxysilane and mix well, react at 70°C for 3 hours, and obtain vinyl silica after centrifugation, washing and drying. Step S2: Mix 40 parts vinyl silica, 120 parts flame retardant, and 2 parts 2-hydroxy-2-methyl-1-phenyl-1-propanone evenly. After ultraviolet irradiation, the mixture is irradiated at a wavelength of 400 nm for 60 min at an intensity of 20 mW / cm². 2 Modified silica was obtained; The preparation method of flame retardant is as follows: Step 1: Mix 24 parts of L-cysteine, 52.8 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and 56 parts of ethanol evenly, react at 50°C for 5 hours, and then distill under reduced pressure to obtain modified L-cysteine. Step 2: Mix 7.5 parts of melamine and 90 parts of pyridine, heat to 50°C, stir until the melamine is completely dissolved, introduce nitrogen gas, add 24 parts of modified L-cysteine ​​and 11.25 parts of dicyclohexylcarbodiimide and mix evenly, heat to 70°C, keep the reaction at this temperature for 4 hours, filter, remove the solvent by vacuum distillation, and dry under vacuum to obtain a mercapto-containing compound; Step 3: Under nitrogen protection, 24 parts of mercapto-containing compound, 120 parts of 2-thiophene formaldehyde and 288 parts of anhydrous ethanol are mixed evenly and reacted at 60°C for 6 hours. The temperature is then raised to 80°C, 96 parts of DOPO are added, and the reaction continues for 10 hours. After cooling to room temperature, the mixture is filtered, washed and dried to obtain the flame retardant.

[0026] Comparative Example 1: A method for preparing a high-strength, tear-resistant, halogen-free, flame-retardant insulating material, comprising the following processes: Compared with Example 2, Comparative Example 1 did not introduce flame retardants, but replaced the modified silica with the same mass of silica, and the other steps were the same as in Example 2.

[0027] Comparative Example 2: A method for preparing a high-strength, tear-resistant, halogen-free, flame-retardant insulating material, comprising the following processes: Compared with Example 2, Comparative Example 2 replaced the flame retardant with the same mass of a mercapto-containing compound, while the other steps were the same as in Example 2.

[0028] Comparative Example 3: A method for preparing a high-strength, tear-resistant, halogen-free, flame-retardant insulating material, comprising the following processes: The preparation method of flame retardant is as follows: Under nitrogen protection, 12 parts of melamine, 48 parts of 2-thiophene formaldehyde and 130 parts of anhydrous ethanol were mixed evenly and reacted at 65°C for 7 hours. The temperature was raised to 85°C, 36 parts of DOPO were added, and the reaction was continued for 11 hours. After cooling to room temperature, the flame retardant was obtained by filtration, washing and drying. Compared with Example 2, Comparative Example 3 did not introduce modified L-cysteine, and the other steps were the same as in Example 2.

[0029] Comparative Example 4: A method for preparing a high-strength, tear-resistant, halogen-free, flame-retardant insulating material, comprising the following processes: The preparation method of flame retardant is as follows: Step 1: Mix 36 parts of L-cysteine, 75 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and 180 parts of ethanol evenly, react at 40℃ for 4 hours, and distill under reduced pressure to obtain modified L-cysteine. Step 2: Mix 12 parts of melamine and 130 parts of pyridine, heat to 45°C, stir until the melamine is completely dissolved, introduce nitrogen gas, add 36 parts of modified L-cysteine ​​and 15 parts of dicyclohexylcarbodiimide and mix evenly, heat to 65°C, keep the reaction at this temperature for 2 hours, filter, remove the solvent by vacuum distillation, and dry under vacuum to obtain a mercapto-containing compound; Step 3: Under nitrogen protection, 12 parts of mercapto-containing compound, 48 parts of 2-thiophene carboxaldehyde and 130 parts of anhydrous ethanol are mixed evenly and reacted at 65°C for 7 hours. The temperature is raised to 85°C, 12 parts of DOPO are added, and the reaction continues for 11 hours. After cooling to room temperature, the flame retardant is obtained by filtration, washing and drying. Compared with Example 2, in step three of Comparative Example 4, the amount of DOPO used was 1 times the total weight of the mercapto-containing compound, and the other steps were the same as in Example 2.

[0030] Experiment: High-strength tear-resistant halogen-free flame-retardant insulating materials obtained in Examples 1-3 and Comparative Examples 1-4 were used to prepare samples. Their properties were tested and the test results were recorded. The oxygen index (LOI value) was determined according to GB / T 2406.2-2009 "Determination of flammability of plastics by oxygen index method - Part 2: Room temperature test", with a specimen size of 100mm × 6.5mm × 3mm. The national standard GB / T 10707 "Determination of flammability of rubber" was used, with a specimen size of 125mm × 6.5mm × 3mm. Tensile properties were determined according to GB / T 1040.3-2006 "Test of tensile properties of plastics", using a universal electronic tensile testing machine at room temperature, with a tensile rate of 50mm / min, and a specimen size of 100mm × 10mm × 1mm. Tear resistance was tested according to GB / T 529-2008 "Determination of tear strength of vulcanized rubber or thermoplastic rubber (trouser-shaped, right-angled and crescent-shaped specimens)", using trouser-shaped (right-angled) specimens, with a tensile rate of 500mm / min.

[0031] The test results are shown in Table 1.

[0032] Table 1 Test Results of High-Strength Tear-Resistant Halogen-Free Flame-Retardant Insulating Materials

[0033] Based on the data in the table above, the following conclusions can be clearly drawn: Compared with Examples 1-3, the oxygen index, tensile strength and tear strength of the products obtained in Comparative Examples 1 and 2 all decreased, indicating that the modified silica prepared by the present invention has better flame retardant effect and compatibility than silica, thereby effectively improving the flame retardant performance and mechanical properties of the material; compared with mercapto-containing compounds, the flame retardant prepared by the present invention has better modification effect, thereby improving the compatibility between inorganic fillers and resin matrix.

[0034] Compared with Examples 1-3, the oxygen index, tensile strength and tear strength of the product obtained in Comparative Example 3 all decreased. This indicates that the flame retardant prepared in this invention, by introducing modified L-cysteine, introduces Si and S elements, which enhances the synergistic effect of flame retardancy in the gas phase and condensed phase. At the same time, the active thiol group at the end of its molecule serves as a highly efficient click chemical reaction site, forming a stable chemical crosslink with vinyl silica, thereby simultaneously improving the strength and tear resistance of the material.

[0035] Compared with Examples 1-3, the oxygen index of the product obtained in Comparative Example 4 decreased, indicating that reducing the amount of DOPO added will reduce the flame retardant properties of the material.

[0036] 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 the spirit or essential characteristics of the invention. 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, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing a high-strength, tear-resistant, halogen-free, flame-retardant insulating material, characterized in that: Includes the following steps: Ethylene propylene diene monomer (EPDM), thermoplastic elastomer, medium-density polyethylene (MDPE), and ethylene-vinyl acetate copolymer are added to a Banbury mixer and mixed at 95-105°C for 2-3 minutes. Aluminum hydroxide, modified silica, polyethylene wax, silicone masterbatch, zinc oxide, antioxidant, and UV absorber are then added and mixed at 160-170°C for 15-25 minutes. The mixture is then discharged to obtain a rubber compound. The rubber compound is then mixed evenly with triallyl isocyanate, sulfur, and an accelerator, and subjected to open milling to obtain a compound. The compound is then subjected to crosslinking via electron accelerator irradiation to obtain a high-strength, tear-resistant, halogen-free, flame-retardant insulating material.

2. The process for preparing a high strength, tear resistant, halogen free, flame retardant insulation material as claimed in claim 1, wherein the said process is characterized by: The high-strength, tear-resistant, halogen-free, flame-retardant insulating material comprises the following components by weight: 70-90 parts EPDM rubber, 5-15 parts thermoplastic elastomer, 15-25 parts medium-density polyethylene, 10-20 parts ethylene-vinyl acetate copolymer, 3-5 parts triallyl isocyanate, 2-4 parts sulfur, 1-3 parts polyethylene wax, 3-5 parts zinc oxide, 1-3 parts antioxidant, 30-50 parts aluminum hydroxide, 20-40 parts modified silica, 0.2-0.5 parts ultraviolet absorber, 1-3 parts accelerator, and 2-4 parts silicone masterbatch.

3. The method for preparing a high-strength, tear-resistant, halogen-free, flame-retardant insulating material according to claim 1, characterized in that: The thermoplastic elastomer is an ethylene-propylene copolymer.

4. The method for preparing a high-strength, tear-resistant, halogen-free, flame-retardant insulating material according to claim 1, characterized in that: The modified silica is prepared as follows: Step S1: Disperse silica ultrasonically in a mixed solution of anhydrous ethanol and deionized water, add vinyltrimethoxysilane and mix well, react at 70-80℃ for 3-5 hours, and obtain vinyl silica after centrifugation, washing and drying. Step S2: Mix vinyl silica, flame retardant and photoinitiator evenly, and react with ultraviolet light to obtain modified silica.

5. The method for preparing a high-strength, tear-resistant, halogen-free, flame-retardant insulating material according to claim 4, characterized in that: In step S2, the mass ratio of vinyl silica, flame retardant and photoinitiator is 1:(1-3):(0.03-0.05).

6. The method for preparing a high-strength, tear-resistant, halogen-free, flame-retardant insulating material according to claim 5, characterized in that: The flame retardant is prepared as follows: Step 1: Mix L-cysteine, 3-(2,3-epoxypropoxy)propyltrimethoxysilane and ethanol evenly, react at 30-50℃ for 3-5 hours, and then distill under reduced pressure to obtain modified L-cysteine. Step 2: Mix melamine and pyridine, heat to 40-50℃, stir until melamine is completely dissolved, introduce nitrogen gas, add modified L-cysteine ​​and dicyclohexylcarbodiimide and mix evenly, heat to 60-70℃, keep the temperature for 2-4 hours, filter, remove solvent by vacuum distillation, and dry under vacuum to obtain a mercapto-containing compound. Step 3: Under nitrogen protection, mix the mercapto compound, 2-thiophene formaldehyde and anhydrous ethanol evenly, react at 60-70℃ for 6-8 hours, raise the temperature to 80-90℃, add DOPO, continue the reaction for 10-12 hours, cool to room temperature, filter, wash and dry to obtain the flame retardant.

7. The method for preparing a high-strength, tear-resistant, halogen-free, flame-retardant insulating material according to claim 6, characterized in that: In step one, the mass ratio of L-cysteine, 3-(2,3-epoxypropoxy)propyltrimethoxysilane and ethanol is 1:(2.0-2.2):(4-6).

8. The method for preparing a high-strength, tear-resistant, halogen-free, flame-retardant insulating material according to claim 6, characterized in that: In step three, the amount of DOPO used is 2-4 times the total weight of the mercapto-containing compounds.

9. The method for preparing a high-strength, tear-resistant, halogen-free, flame-retardant insulating material according to claim 1, characterized in that: The accelerator is accelerator CZ.

10. A high-strength, tear-resistant, halogen-free, flame-retardant insulating material prepared by the preparation method according to any one of claims 1-9.

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