High-strength low-voltage power cable

Abstract

The invention relates to the technical field of cable preparation, and provides a high-strength low-voltage power cable, which comprises a cable core, and an aluminum-plastic composite wrapping tape, a mica wrapping tape and a sheath layer which sequentially wrap the cable core from inside to outside, the sheath layer comprises the following substances: an ethylene-vinyl acetate copolymer, linear low-density polyethylene resin, a modified flame retardant, montmorillonite, a light stabilizer, a lubricant, an antioxidant and polyethylene grafted maleic anhydride; wherein a preparation process of the modified flame retardant comprises the following steps: mixing melamine hydrobromide, absolute ethyl alcohol and deionized water, uniformly stirring, raising the temperature, adding a composite additive, stirring to react, cooling to room temperature after the reaction is finished, and drying to obtain the modified flame retardant. The preparation method has the beneficial effects that the surface of the melamine hydrobromide is coated, so that the antagonism between the melamine hydrobromide and the light stabilizer is reduced; in addition, long-chain alkyl groups and flame-retardant groups contained in the flame-retardant polyester resin further improve the flame-retardant effect and the mechanical property of the material.

Description

Technical Field

[0001] The present invention relates to the technical field of cable preparation, and in particular to a high-strength low-voltage power cable. Background Art

[0002] At present, low-voltage power cables are widely used in construction, industry, energy and other fields, but their sheath materials often face problems such as insufficient mechanical properties, poor flame retardant effect and poor weather resistance.

[0003] Traditional cable sheaths are often constructed from polyethylene (PE) or polyvinyl chloride (PVC) as a base material. While relatively inexpensive, the oxygen index of common PE is only 17%-19%, making it difficult to meet high flame retardancy requirements. While PVC exhibits some flame retardancy, it releases toxic gases when burned and is susceptible to aging and brittleness after long-term use. To improve flame retardancy, existing technologies often add halogenated flame retardants (such as decabromodiphenyl ether). However, these halogenated flame retardants interact antagonistically with light stabilizers and antioxidants, leading to rapid degradation of the material under UV irradiation and a significant decrease in mechanical properties. Furthermore, conventional inorganic flame retardants (such as aluminum hydroxide and magnesium hydroxide) require high filler levels (40%-60%) to meet flame retardancy standards, which significantly degrades the material's mechanical strength and processing properties. Although some studies have attempted to modify flame retardants with silane coupling agents to improve dispersibility, a single modification approach is unlikely to simultaneously address the issues of low flame retardancy, poor light stability, and diminished mechanical properties.

[0004] Therefore, in order to solve the above problems, the present invention proposes a high-strength low-voltage power cable. Summary of the Invention

[0005] The present invention provides a high-strength low-voltage power cable, which solves the defects in the related art.

[0006] The technical solutions of the present invention are as follows: A high-strength low-voltage power cable comprises a cable core and an aluminum-plastic composite tape, a mica wrapping tape, and a sheath layer, which sequentially cover the cable core from the inside out. The sheath layer comprises the following components, by weight: 20-25 parts of ethylene-vinyl acetate copolymer, 60-70 parts of linear low-density polyethylene resin, 20-30 parts of a modified flame retardant, 4-5 parts of montmorillonite, 1-2 parts of a light stabilizer, 1-2 parts of a lubricant, 1-2 parts of an antioxidant, and 1-2 parts of polyethylene grafted maleic anhydride. The modified flame retardant is prepared by mixing melamine hydrobromide, anhydrous ethanol, and deionized water, stirring for 30-40 minutes until the mixture is uniformly mixed, then raising the temperature to 70-80°C, adding a composite additive, stirring and reacting for 6-7 hours, cooling to room temperature after the reaction, collecting the product, and drying it in an oven at 80°C to constant weight to obtain the modified flame retardant.

[0007] More optimally, the raw materials for preparing the modified flame retardant include the following components: 10-15 parts of melamine hydrobromide, 50-60 parts of anhydrous ethanol, 60-80 parts of deionized water, and 1-2 parts of composite additives in total.

[0008] More optimally, the composite additive includes dodecyltrimethoxysilane and modified silane in a mass ratio of 3:1.

[0009] In the scheme, dodecyltrimethoxysilane and modified silane are hydrolyzed in a water and ethanol system to generate silanol structures; and due to the hydrogen bonding between the amino groups on the surface of melamine hydrobromide and the hydroxyl groups of the silanol, melamine hydrobromide can better serve as a nucleation site. Therefore, the silanol structure will preferentially adsorb on the surface of melamine hydrobromide, and then undergo dehydration condensation to form a polymer network.

[0010] More optimally, the light stabilizer is light stabilizer 119.

[0011] More optimally, the preparation process of the modified silane is: S1: 4-formylphenylboronic acid, p-aminobenzaldehyde, and methanol were mixed evenly, the temperature was raised to 60°C, and the reaction was stirred for 4-5 hours to obtain an intermediate product; 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was then dissolved in methanol and added to the intermediate product within 30 minutes. The reaction was continued at 60°C for 10-12 hours. After the reaction was completed, the methanol was removed by rotary evaporation, and the solid was washed with anhydrous ethanol, filtered, and dried under high vacuum at 80°C for 12 hours to obtain intermediate A; S2: Under a protective atmosphere, intermediate A, γ-aminopropyltriethoxysilane, and anhydrous ethanol were mixed, sealed, and the temperature was raised to 60-70°C. The mixture was stirred and reacted for 10-12 hours. After the reaction was completed, the mixture was cooled to room temperature, concentrated, and allowed to stand for 24 hours. The mixture was washed and dried to obtain the modified silane.

[0012] In the scheme, 4-formylphenylboronic acid (containing an aldehyde group) and p-aminobenzaldehyde (containing an amino group) undergo a condensation reaction in a methanol solvent to form a Schiff base structure, which then undergoes a nucleophilic addition reaction with the pH bond of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to obtain intermediate A. The specific synthesis process is shown below:

[0013] More optimally, the raw materials for preparing the intermediate A include the following components: by weight, 15-16 parts of 4-formylphenylboronic acid, 13-14 parts of p-aminobenzaldehyde, 140-180 parts of methanol, and 20-22 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0014] In the scheme, the aldehyde group contained in intermediate A reacts with the amino group of γ-aminopropyltriethoxysilane under a protective atmosphere and anhydrous conditions to form a Schiff base reaction to obtain a modified silane. The specific synthesis process is as follows:

[0015] More optimally, the raw materials for preparing the modified silane include the following components: 4-5 parts of intermediate A, 2-3 parts of γ-aminopropyltriethoxysilane, and 20-30 parts of anhydrous ethanol, by weight.

[0016] More optimally, the cable core is a copper alloy conductor.

[0017] More optimally, the lubricant includes one or more of zinc stearate, calcium stearate, barium stearate or polyethylene wax.

[0018] More optimally, the antioxidant is antioxidant 1010.

[0019] Compared with the prior art, the present invention has the following advantages: The present invention coats the surface of melamine hydrobromide, thereby reducing the antagonistic effect between it and the light stabilizer; and further enhancing the flame retardant effect and mechanical properties of the material due to the long-chain alkyl and flame retardant groups it contains. First, melamine hydrobromide releases hydrogen bromide when exposed to heat or light, creating acidic conditions. Its decomposition products can react with the alkaline structure of light stabilizer 119 to neutralize it, causing the light stabilizer to be inactivated. In this solution, the coating acts as a physical barrier, encapsulating melamine hydrobromide inside, preventing hydrogen bromide from diffusing to the outside and avoiding direct contact with the light stabilizer, allowing the light stabilizer to continue to play its free radical capture role.

[0020] Second, the coating reflects UV light, working together with the light stabilizer to reduce photooxidative damage to the material matrix. Furthermore, the light stabilizer not only captures free radicals generated by photooxidation but also quenches alkyl radicals produced by polymer degradation during the initial stages of combustion, slowing the rate of thermal decomposition and buying time for the carbonization process. Furthermore, the solution integrates potent phosphorus-based flame retardants (DOPO derivatives, which capture gas-phase free radicals and provide strong solid-phase catalytic carbonization) and boron-based flame retardants (phenylboronic acid derivatives, which form a strong glassy barrier at high temperatures) into a single molecule. This is ultimately grafted onto the surface of the main flame retardant particles via silane groups, further enhancing the material's flame retardancy. Furthermore, the introduction of long-chain alkylsilanes (dodecyl groups) provides steric hindrance and compatibility with polyolefins, reducing agglomeration and promoting uniform dispersion of the flame retardant particles in the matrix, improving the material's mechanical properties. DETAILED DESCRIPTION

[0021] 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 any creative efforts are within the scope of protection of the present invention.

[0022] It should be noted that in the following examples and comparative examples, the CAS value of melamine hydrobromide is 29305-12-2; the CAS value of 4-formylphenylboronic acid is 87199-17-5; the CAS value of polyethylene grafted maleic anhydride is 9006-26-2; the mass percentage of vinyl acetate in the ethylene-vinyl acetate copolymer is 20%; and the linear low-density polyethylene (MLLDPE) is Exxon Mobil 3518CB, purchased from ExxonMobil.

[0023] Example 1 A high-strength low-voltage power cable, comprising a cable core (copper alloy conductor) and an aluminum-plastic composite tape, a mica wrapping tape, and a sheath layer covering the cable core in sequence from the inside out; the sheath layer comprises the following components, by weight: 20 parts of ethylene-vinyl acetate copolymer, 60 parts of linear low-density polyethylene resin, 20 parts of modified flame retardant, 4 parts of montmorillonite, 1 part of light stabilizer (light stabilizer 119), 1 part of lubricant (zinc stearate), 1 part of antioxidant 1010, and 1 part of polyethylene grafted maleic anhydride; The preparation process of the modified flame retardant is as follows: 10 parts of melamine hydrobromide, 50 parts of anhydrous ethanol and 60 parts of deionized water are mixed and stirred for 30 minutes until the mixture is uniform. Then, the temperature is raised to 70°C, 1 part of a composite additive (including dodecyltrimethoxysilane and modified silane in a mass ratio of 3:1) is added, and the mixture is stirred for 6 hours. After the reaction is completed, the mixture is cooled to room temperature, the product is collected, and dried in an oven at 80°C to constant weight to obtain the modified flame retardant. Among them, the preparation process of modified silane is: S1: 15 parts of 4-formylphenylboronic acid, 13 parts of p-aminobenzaldehyde, and 80 parts of methanol were mixed evenly, the temperature was raised to 60°C, and the mixture was stirred and reacted for 4 hours to obtain an intermediate product; then 20 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were dissolved in 60 parts of methanol and added to the intermediate product within 30 minutes, and the mixture was continued to react at 60°C for 10 hours. After the reaction was completed, the methanol was removed by rotary evaporation, and the solid was washed with anhydrous ethanol, filtered, and dried under high vacuum at 80°C for 12 hours to obtain intermediate A; S2: Under a protective atmosphere, 4 parts of intermediate A, 2 parts of γ-aminopropyltriethoxysilane, and 20 parts of anhydrous ethanol were mixed, sealed, and the temperature was raised to 60°C. The mixture was stirred and reacted for 10 hours. After the reaction was completed, it was cooled to room temperature, concentrated, and allowed to stand for 24 hours. The modified silane was then washed and dried to obtain the modified silane. The preparation method of the sheath layer pellets is as follows: 20 parts of ethylene-vinyl acetate copolymer, 60 parts of linear low-density polyethylene resin, 20 parts of modified flame retardant, 4 parts of montmorillonite, 1 part of light stabilizer (light stabilizer 119), 1 part of lubricant (zinc stearate), 1 part of antioxidant 1010, and 1 part of polyethylene grafted maleic anhydride are placed in a high-speed mixer, mixed at 100°C for 20 minutes, and then transferred to a twin-screw extruder. The extruded material strips are cooled in a water cooling tank and then pelletized to obtain the sheath layer pellets.

[0024] Example 2 A high-strength low-voltage power cable, comprising a cable core (copper alloy conductor) and an aluminum-plastic composite tape, a mica wrapping tape, and a sheath layer covering the cable core in sequence from the inside out; the sheath layer comprises the following components, by weight: 25 parts of ethylene-vinyl acetate copolymer, 70 parts of linear low-density polyethylene resin, 30 parts of modified flame retardant, 5 parts of montmorillonite, 2 parts of light stabilizer (light stabilizer 119), 2 parts of lubricant (zinc stearate), 2 parts of antioxidant 1010, and 2 parts of polyethylene grafted maleic anhydride; The preparation process of the modified flame retardant is as follows: 15 parts of melamine hydrobromide, 60 parts of anhydrous ethanol and 80 parts of deionized water are mixed and stirred for 40 minutes until the mixture is uniformly mixed. Then, the temperature is raised to 80°C, 2 parts of a composite additive (including dodecyltrimethoxysilane and modified silane in a mass ratio of 3:1) are added, and the mixture is stirred for 7 hours. After the reaction is completed, the mixture is cooled to room temperature, the product is collected, and dried in an oven at 80°C to constant weight to obtain the modified flame retardant. Among them, the preparation process of modified silane is: S1: 16 parts of 4-formylphenylboronic acid, 14 parts of p-aminobenzaldehyde, and 100 parts of methanol were mixed evenly, the temperature was raised to 60°C, and the reaction was stirred for 5 hours to obtain an intermediate product; then 22 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were dissolved in 80 parts of methanol and added to the intermediate product within 30 minutes, and the reaction was continued at 60°C for 12 hours. After the reaction was completed, the methanol was removed by rotary evaporation, and the solid was washed with anhydrous ethanol, filtered, and dried under high vacuum at 80°C for 12 hours to obtain intermediate A; S2: Under a protective atmosphere, 5 parts of intermediate A, 3 parts of γ-aminopropyltriethoxysilane, and 30 parts of anhydrous ethanol were mixed, sealed, and the temperature was raised to 70°C. The mixture was stirred and reacted for 12 hours. After the reaction was completed, it was cooled to room temperature, concentrated, and allowed to stand for 24 hours. The modified silane was then washed and dried to obtain the modified silane. The preparation method of the sheath layer pellets is as follows: 25 parts of ethylene-vinyl acetate copolymer, 70 parts of linear low-density polyethylene resin, 30 parts of modified flame retardant, 5 parts of montmorillonite, 2 parts of light stabilizer (light stabilizer 119), 2 parts of lubricant (zinc stearate), 2 parts of antioxidant 1010, and 2 parts of polyethylene grafted maleic anhydride are placed in a high-speed mixer, mixed at 100°C for 20 minutes, and then transferred to a twin-screw extruder. The extruded material strips are cooled in a water cooling tank and then pelletized to obtain the sheath layer pellets.

[0025] Example 3 A high-strength low-voltage power cable, comprising a cable core (copper alloy conductor) and an aluminum-plastic composite tape, a mica wrapping tape, and a sheath layer covering the cable core in sequence from the inside out; the sheath layer comprises the following components, by weight: 22.5 parts of ethylene-vinyl acetate copolymer, 65 parts of linear low-density polyethylene resin, 25 parts of modified flame retardant, 4.5 parts of montmorillonite, 1.5 parts of light stabilizer (light stabilizer 119), 1.5 parts of lubricant (zinc stearate), 1.5 parts of antioxidant 1010, and 1.5 parts of polyethylene grafted maleic anhydride; The preparation process of the modified flame retardant is as follows: 12.5 parts of melamine hydrobromide, 55 parts of anhydrous ethanol and 70 parts of deionized water are mixed and stirred for 35 minutes until the mixture is uniform. Then, the temperature is raised to 75°C, 1.5 parts of a composite additive (including dodecyltrimethoxysilane and modified silane in a mass ratio of 3:1) is added, and the mixture is stirred for 6.5 hours. After the reaction is completed, the mixture is cooled to room temperature, the product is collected, and dried in an oven at 80°C to constant weight to obtain the modified flame retardant. Among them, the preparation process of modified silane is: S1: 15.5 parts of 4-formylphenylboronic acid, 13.5 parts of p-aminobenzaldehyde, and 90 parts of methanol were mixed evenly, the temperature was raised to 60°C, and the mixture was stirred and reacted for 4.5 hours to obtain an intermediate product; then 21 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were dissolved in 70 parts of methanol and added to the intermediate product within 30 minutes, and the mixture was continued to react at 60°C for 11 hours. After the reaction was completed, the methanol was removed by rotary evaporation, and the solid was washed with anhydrous ethanol, filtered, and dried under high vacuum at 80°C for 12 hours to obtain intermediate A; S2: Under a protective atmosphere, 4.5 parts of intermediate A, 2.5 parts of γ-aminopropyltriethoxysilane, and 25 parts of anhydrous ethanol were mixed, sealed, and the temperature was raised to 65°C. The mixture was stirred and reacted for 11 hours. After the reaction was completed, it was cooled to room temperature, concentrated, and allowed to stand for 24 hours. The modified silane was then washed and dried to obtain the modified silane. The preparation method of the sheath layer pellets is as follows: 22.5 parts of ethylene-vinyl acetate copolymer, 65 parts of linear low-density polyethylene resin, 25 parts of modified flame retardant, 4.5 parts of montmorillonite, 1.5 parts of light stabilizer (light stabilizer 119), 1.5 parts of lubricant (zinc stearate), 1.5 parts of antioxidant 1010, and 1.5 parts of polyethylene grafted maleic anhydride are placed in a high-speed mixer, mixed at 100°C for 20 minutes, and then transferred to a twin-screw extruder. The extruded material strips are cooled in a water cooling tank and then pelletized to obtain the sheath layer pellets.

[0026] Comparative Example 1 Melamine hydrobromide was not modified, and the rest was the same as in Example 3, specifically as follows: A high-strength low-voltage power cable, comprising a cable core (copper alloy conductor) and an aluminum-plastic composite tape, a mica wrapping tape, and a sheath layer covering the cable core in sequence from the inside out; the sheath layer comprises the following components, by weight: 22.5 parts of ethylene-vinyl acetate copolymer, 65 parts of linear low-density polyethylene resin, 25 parts of a flame retardant (melamine hydrobromide), 4.5 parts of montmorillonite, 1.5 parts of a light stabilizer (light stabilizer 119), 1.5 parts of a lubricant (zinc stearate), 1.5 parts of an antioxidant 1010, and 1.5 parts of polyethylene grafted maleic anhydride; The preparation method of the sheath layer pellets is as follows: 22.5 parts of ethylene-vinyl acetate copolymer, 65 parts of linear low-density polyethylene resin, 25 parts of flame retardant (melamine hydrobromide), 4.5 parts of montmorillonite, 1.5 parts of light stabilizer (light stabilizer 119), 1.5 parts of lubricant (zinc stearate), 1.5 parts of antioxidant 1010, and 1.5 parts of polyethylene grafted maleic anhydride are placed in a high-speed mixer, mixed at 100°C for 20 minutes, and then transferred to a twin-screw extruder. The extruded material strips are cooled in a water cooling tank and then pelletized to obtain the sheath layer pellets.

[0027] Comparative Example 2 No modified silane was introduced to modify melamine hydrobromide, and the rest was the same as in Example 3, specifically as follows: A high-strength low-voltage power cable, comprising a cable core (copper alloy conductor) and an aluminum-plastic composite tape, a mica wrapping tape, and a sheath layer covering the cable core in sequence from the inside out; the sheath layer comprises the following components, by weight: 22.5 parts of ethylene-vinyl acetate copolymer, 65 parts of linear low-density polyethylene resin, 25 parts of modified flame retardant, 4.5 parts of montmorillonite, 1.5 parts of light stabilizer (light stabilizer 119), 1.5 parts of lubricant (zinc stearate), 1.5 parts of antioxidant 1010, and 1.5 parts of polyethylene grafted maleic anhydride; The preparation process of the modified flame retardant is as follows: 12.5 parts of melamine hydrobromide, 55 parts of anhydrous ethanol and 70 parts of deionized water are mixed and stirred for 35 minutes until the mixture is uniformly mixed, then the temperature is increased to 75°C, 1.5 parts of dodecyltrimethoxysilane are added, and the mixture is stirred for 6.5 hours. After the reaction is completed, the mixture is cooled to room temperature, the product is collected, and dried in an oven at 80°C to constant weight to obtain the modified flame retardant; The preparation method of the sheath layer pellets is as follows: 22.5 parts of ethylene-vinyl acetate copolymer, 65 parts of linear low-density polyethylene resin, 25 parts of modified flame retardant, 4.5 parts of montmorillonite, 1.5 parts of light stabilizer (light stabilizer 119), 1.5 parts of lubricant (zinc stearate), 1.5 parts of antioxidant 1010, and 1.5 parts of polyethylene grafted maleic anhydride are placed in a high-speed mixer, mixed at 100°C for 20 minutes, and then transferred to a twin-screw extruder. The extruded material strips are cooled in a water cooling tank and then pelletized to obtain the sheath layer pellets.

[0028] Detection experiment: (1) The tensile strength of the sheath layer granules of the embodiment and the comparative example was tested in accordance with the standard GB / T 1040.3-2006; (2) According to the standard GB / T 2406.3-2022, the sheath layer granules of the embodiment and the comparative example were subjected to high temperature tests to determine their oxygen index; (3) The sheath layer granules prepared in the examples and comparative examples were subjected to UV aging test (60h, 50W / m 2 , 340nm), and then the tensile strength and oxygen index of the aged material were tested; The obtained data is shown in the following table:

[0029] Conclusion: The high-strength, low-voltage power cable provided by the present invention significantly improves the tensile strength and flame retardancy of the cable by optimizing the formulation and preparation process of the sheath layer material. The sheath layer pellets of Examples 1-3 exhibited excellent tensile strength (26.6-27.1 MPa) and oxygen index (32.3-33.1%) in their initial state, demonstrating their high mechanical strength and flame retardancy. Even after UV aging testing, these properties remained at high levels (tensile strength 24.1-24.6 MPa, oxygen index 30.5-31.4%), demonstrating the material's excellent weather resistance and stability.

[0030] In contrast, Comparative Example 1, which did not modify the melamine hydrobromide, resulted in a significant decrease in its tensile strength and oxygen index (initial tensile strength 17.9 MPa, oxygen index 26.7%; after aging, tensile strength 14.2 MPa, oxygen index 24.3%). This was primarily due to the antagonistic effect between the unmodified melamine hydrobromide and the light stabilizer, with the release of hydrogen bromide disrupting the light stabilizer's function. Furthermore, the flame retardant had poor dispersibility, affecting the overall performance of the material. Comparative Example 2, which partially modified the melamine hydrobromide but did not introduce a modified silane, performed better than Comparative Example 1 (initial tensile strength 22.9 MPa, oxygen index 28.9%; after aging, tensile strength 19.8 MPa, oxygen index 26.7%), but still inferior to the Examples. This was due to the lack of synergistic effects from the modified silane, resulting in limited improvements in flame retardancy and mechanical properties.

[0031] In summary, the cable of the present invention effectively solves the compatibility problem between flame retardants and light stabilizers by modifying the flame retardant and optimizing the formula, while improving the mechanical properties and weather resistance of the material, and has significant technical advantages.

[0032] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-strength low-voltage power cable, characterized in that: The invention comprises a cable core and an aluminum-plastic composite tape, a mica wrapping tape and a sheath layer which sequentially cover the cable core from the inside out; the sheath layer comprises the following components, by weight: 20-25 parts of ethylene-vinyl acetate copolymer, 60-70 parts of linear low-density polyethylene resin, 20-30 parts of modified flame retardant, 4-5 parts of montmorillonite, 1-2 parts of light stabilizer, 1-2 parts of lubricant, 1-2 parts of antioxidant, and 1-2 parts of polyethylene grafted maleic anhydride; wherein the preparation process of the modified flame retardant is as follows: melamine hydrobromide, anhydrous ethanol and deionized water are mixed, stirred for 30-40 minutes until the mixture is uniform, then the temperature is increased to 70-80°C, a composite additive is added, the reaction is stirred for 6-7 hours, and after the reaction is completed, the mixture is cooled to room temperature, the product is collected, and dried in an oven at 80°C to constant weight to obtain the modified flame retardant.

2. A high-strength low-voltage power cable according to claim 1, characterized in that: The raw materials for preparing the modified flame retardant include the following components: 10-15 parts of melamine hydrobromide, 50-60 parts of anhydrous ethanol, 60-80 parts of deionized water, and 1-2 parts of a composite additive in total.

3. A high-strength low-voltage power cable according to claim 1, characterized in that: The composite additive comprises dodecyltrimethoxysilane and modified silane in a mass ratio of 3:

1.

4. A high-strength low-voltage power cable according to claim 1, characterized in that: The light stabilizer is light stabilizer 119.

5. A high-strength low-voltage power cable according to claim 3, characterized in that: The preparation process of the modified silane is: S1: 4-formylphenylboronic acid, p-aminobenzaldehyde, and methanol were mixed evenly, the temperature was raised to 60°C, and the reaction was stirred for 4-5 hours to obtain an intermediate product; 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was then dissolved in methanol and added to the intermediate product within 30 minutes. The reaction was continued at 60°C for 10-12 hours. After the reaction was completed, the methanol was removed by rotary evaporation, and the solid was washed with anhydrous ethanol, filtered, and dried under high vacuum at 80°C for 12 hours to obtain intermediate A; S2: Under a protective atmosphere, intermediate A, γ-aminopropyltriethoxysilane, and anhydrous ethanol were mixed, sealed, and the temperature was raised to 60-70°C. The mixture was stirred and reacted for 10-12 hours. After the reaction was completed, the mixture was cooled to room temperature, concentrated, and allowed to stand for 24 hours. The mixture was washed and dried to obtain the modified silane.

6. A high-strength low-voltage power cable according to claim 5, characterized in that: The raw materials for preparing the intermediate A include the following components: by weight, 15-16 parts of 4-formylphenylboronic acid, 13-14 parts of p-aminobenzaldehyde, 140-180 parts of methanol, and 20-22 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

7. A high-strength low-voltage power cable according to claim 5, characterized in that: The raw materials for preparing the modified silane include the following components: 4-5 parts of intermediate A, 2-3 parts of gamma-aminopropyltriethoxysilane, and 20-30 parts of anhydrous ethanol, calculated by weight.

8. The high-strength low-voltage power cable according to claim 1, characterized in that: The cable core is a copper alloy conductor.

9. The high-strength low-voltage power cable according to claim 1, characterized in that: The lubricant includes one or more of zinc stearate, calcium stearate, barium stearate or polyethylene wax.

10. The high-strength low-voltage power cable according to claim 1, characterized in that: The antioxidant is antioxidant 1010.

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