High-temperature-resistant flame-retardant cable

Abstract

The invention relates to the technical field of cable preparation, and provides a high-temperature-resistant flame-retardant cable, which comprises a cable core, and an insulating layer and a sheath layer which sequentially coat the cable core from inside to outside, the sheath layer is prepared from the following components in parts by weight: 8 to 10 parts of ethylene-vinyl acetate copolymer, 15 to 18 parts of ethylene-acrylate copolymer, 15 to 18 parts of polyvinyl chloride resin, 15 to 20 parts of filler, 10 to 12 parts of modified glass fiber, 3 to 4 parts of maleic anhydride grafted polyethylene, 0.5 to 1 part of ultraviolet absorbent, 1 to 2 parts of antioxidant and 1 to 2 parts of coupling agent. The cable has the beneficial effects that through introduction of the modified glass fiber and the functional monomer, the mechanical property and the flame retardant grade of the cable are improved, and the stability of the cable in a high-temperature environment is also remarkably enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cable preparation, in particular, it relates to a high-temperature-resistant flame-retardant cable. BACKGROUND

[0002] In the field of cable preparation, the demand for high-temperature-resistant flame-retardant cables is increasing, especially in high-temperature environments or places with high fire risk, such as power systems, chemical facilities, and internal wiring of buildings.

[0003] Currently, the flame-retardant cables on the market mostly use traditional flame-retardant materials, such as polyvinyl chloride (PVC) or composite materials with inorganic fillers (such as aluminum hydroxide and magnesium hydroxide). However, these materials have obvious defects in practical application. First, the tensile strength of traditional flame-retardant cables is low, which can easily lead to cracking or deformation of the sheath layer due to mechanical stress or high-temperature environment, affecting the service life and safety of the cable. Second, the flame-retardant effect of existing flame-retardant materials is limited, with a low oxygen index, which is difficult to meet the requirements of high flame-retardant grades, and may release toxic gases during combustion, exacerbating the fire hazard. In addition, the interface compatibility between unmodified glass fibers and the polymer matrix is poor, which can easily lead to interface defects due to polarity differences, further reducing the mechanical properties and high-temperature resistance of the material. Although some studies attempt to improve performance by adding flame retardants or reinforcing fibers, these methods often cannot simultaneously consider flame retardancy, mechanical strength, and high-temperature resistance, resulting in insufficient comprehensive performance of the cable in complex environments.

[0004] Therefore, in order to solve the above problems, the present application proposes a high-temperature-resistant flame-retardant cable. SUMMARY

[0005] The present application proposes a high-temperature-resistant flame-retardant cable, which solves the defects in the related art.

[0006] The technical solution of the present application is as follows: A high-temperature-resistant flame-retardant cable, comprising a cable core and an insulating layer and a sheath layer successively covering the cable core from the inside to the outside; the sheath layer comprises the following components: 8-10 parts by weight of ethylene-vinyl acetate copolymer, 15-18 parts by weight of ethylene-acrylate copolymer, 15-18 parts by weight of polyvinyl chloride resin, 15-20 parts by weight of filler, 10-12 parts by weight of modified glass fiber, 3-4 parts by weight of maleic anhydride grafted polyethylene, 0.5-1 parts by weight of ultraviolet absorber, 1-2 parts by weight of antioxidant, and 1-2 parts by weight of coupling agent.

[0007] More preferably, the preparation process of the modified glass fiber is as follows: A1: mixing deionized water and anhydrous ethanol, adjusting pH to 4-4.5 using glacial acetic acid, then slowly adding γ-methacryloxypropyl trimethoxysilane, stirring for 30-40 min, then adding glass fiber, raising temperature to 30-40℃, reacting for 60-90 min, after the reaction is completed, separating by suction filtration, washing, and drying to obtain alkenyl glass fiber; A2: (1) slowly adding potassium persulfate to deionized water at a temperature of 40-50℃, stirring while adding until the potassium persulfate is completely dissolved, then naturally cooling to 25℃ to obtain an initiator solution; (2) under a protective atmosphere, mixing alkenyl glass fiber, functional monomer, methyl methacrylate, butyl acrylate, and ethanol, stirring until uniform, then adding part of the initiator solution, raising the temperature to 65-70℃, and reacting for 1-2 h, then continuously adding the remaining initiator solution, after the addition is complete, continuing to react for 3-4 h, after the reaction is completed, washing, and standing at 25℃ for 12 h in a constant temperature room, then drying at 70℃ for 40-50 min to obtain modified glass fiber.

[0008] More preferably, the raw materials for preparing the alkenyl glass fiber include the following components: 8-10 parts by weight of deionized water, 24-30 parts by weight of anhydrous ethanol, 0.2-0.3 parts by weight of γ-methacryloxypropyl trimethoxysilane, and 10-12 parts by weight of glass fiber.

[0009] More preferably, the raw materials for the initiator solution include the following components: 0.1-0.2 parts by weight of potassium persulfate, 80-100 parts by weight of deionized water, 60-80 parts by weight of alkenyl glass fiber, 10-15 parts by weight of functional monomer, 8-10 parts by weight of methyl methacrylate, 3-4 parts by weight of butyl acrylate, and 50-60 parts by weight of ethanol.

[0010] More preferably, the preparation process for the functional monomer is as follows: S1: mixing 3,5-diamino-1,2,4-triazole, triethylamine, and anhydrous tetrahydrofuran, stirring until uniform, maintaining the temperature at 0-5℃, slowly adding acryloyl chloride solution, after the addition is complete, raising the temperature to room temperature, and continuing to stir for 2-3 h, after the reaction is completed, filtering, concentrating, and purifying to obtain intermediate A; S2: (1) adding diphenyl chlorophosphate to anhydrous tetrahydrofuran, stirring until uniform to obtain a diphenyl chlorophosphate solution; (2) mixing 3-methoxy-4-hydroxybenzaldehyde, triethylamine, and anhydrous tetrahydrofuran, stirring until uniform, and placing in an ice water bath to cool, controlling the temperature at 0-5℃, then slowly adding the diphenyl chlorophosphate solution, after the addition is complete, continuing to stir for 30-40 min, then raising the temperature to 60-70℃, and refluxing under nitrogen protection for 10-12 h, after the reaction is completed, naturally cooling to room temperature, and post-treating to obtain intermediate B; S3: mixing intermediate A, intermediate B, p-toluenesulfonic acid, anhydrous ethanol, stirring uniformly, raising temperature to 40-50 DEG C, reacting for 8-10h, after reaction is completed, cooling to room temperature, removing solvent through rotary evaporator, washing, drying, to obtain functional monomer.

[0011] In the scheme, under low temperature (0-5 DEG C), one amino of 3,5-diamino-1,2,4-triazole nucleophilically attacks carbonyl carbon of acryloyl chloride, nucleophilic acyl substitution reaction occurs, to obtain intermediate A.

[0012] More preferably, the preparation raw materials of the intermediate A include the following components: 10-12 parts of 3,5-diamino-1,2,4-triazole, 12-15 parts of triethylamine, 80-100 parts of anhydrous tetrahydrofuran, 15-18 parts of acryloyl chloride solution; wherein the concentration of the acryloyl chloride solution is 25wt%.

[0013] In the scheme, the phenolic hydroxyl of 3-methoxy-4-hydroxybenzaldehyde nucleophilically attacks phosphorus atom of diphenyl chlorophosphate, to replace chlorine atom, to obtain intermediate B.

[0014] More preferably, the preparation raw materials of the intermediate B retain the following components: 12-15 parts of diphenyl chlorophosphate, 60-80 parts of anhydrous tetrahydrofuran, 10-12 parts of 3-methoxy-4-hydroxybenzaldehyde, 8-10 parts of triethylamine.

[0015] In the scheme, under acidic conditions, the amino of intermediate A and the aldehyde group of intermediate B occur nucleophilic addition-dehydration reaction, to obtain functional monomer.

[0016] More preferably, the preparation raw materials of the functional monomer include the following components: 10-12 parts of intermediate A, 15-18 parts of intermediate B, 0.5-1 parts of p-toluenesulfonic acid, 60-70 parts of anhydrous ethanol.

[0017] In the scheme, the synthesis process of the functional monomer is as follows:

[0018] More preferably, the filler includes one or more of aluminum hydroxide, magnesium hydroxide, magnesium oxide.

[0019] More preferably, the antioxidant is antioxidant 168; the ultraviolet absorber is 2-(2'-hydroxy-3',5'-di-tert-pentylphenyl) benzotriazole; the coupling agent is gamma-aminopropyl triethoxysilane.

[0020] Compared with the prior art, the present application has the advantages of: Firstly, in the scheme, by free radical polymerization, methyl methacrylate, butyl acrylate and functional monomer are grafted on the surface of alkenyl glass fiber to form polymer segments. These segments have similarity in chemical structure with the organic matrix in the sheath layer, such as ethylene-acrylate copolymer and ethylene-vinyl acetate copolymer, which can enhance the intermolecular force, reduce the interfacial tension, avoid the interface defects caused by the polarity difference between the unmodified glass fiber and the matrix, and significantly improve the tensile strength of the sheath layer.

[0021] Secondly, the functional monomer is generated by the reaction of intermediate A (containing a triazole ring derived from 3,5-diamino-1,2,4-triazole, a nitrogen-rich structure) and intermediate B (containing a phosphonate group derived from diphenyl chlorophosphate, a phosphorus-containing structure), which simultaneously contains nitrogen and phosphorus flame-retardant elements. During combustion, the nitrogen elements in the triazole ring can release inert gases such as nitrogen, diluting the oxygen and combustible material concentration in the combustion area, achieving gas-phase flame retardation. The phosphorus elements in the phosphonate group catalyze the dehydration of polymers into carbon at high temperatures, forming a dense carbon layer covering the material surface, blocking the transfer of heat and oxygen, achieving condensed-phase flame retardation. The synergistic effect of the two, combined with the heat absorption and cooling effect of fillers such as aluminum hydroxide and magnesium hydroxide in the sheath layer, significantly improves the oxygen index of the material and enhances the flame-retardant grade.

[0022] Thirdly, glass fiber itself has high temperature resistance, and after modification, it forms a stable network structure with the matrix, which can inhibit the thermal motion and disordered packing of polymer molecular chains in high temperature environment, reducing the structural collapse of the matrix due to high temperature softening. Moreover, the aromatic structure (such as benzene ring, triazole ring) in the functional monomer has good thermal stability, which can reduce thermal decomposition at high temperatures. Further improve the high temperature resistance of the material. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. 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.

[0024] In the following examples and comparative examples: Ethylene-vinyl acetate copolymer: model EVA28-40, manufacturer SK, Korea; Ethylene-acrylate copolymer: model EAA3460, manufacturer Dow, USA; Polyvinyl chloride resin: model SG-5, manufacturer Yantai Salt Chemical Co., Ltd.; Glass fiber: length 6 mm, diameter 15 μm; Maleic anhydride grafted polyethylene: item number 111720, brand Karamay.

[0025] Example 1 A method for preparing a high-temperature resistant flame-retardant cable comprises the following steps: preliminarily mixing 8 parts of ethylene-vinyl acetate copolymer, 15 parts of ethylene-acrylate copolymer, and 15 parts of polyvinyl chloride resin in a high-speed mixer at a low speed, adding the mixture to an internal mixer, and kneading the mixture at 120° C. for 3 minutes; then adding 3 parts of maleic anhydride grafted polyethylene and 1 part of a coupling agent (γ-aminopropyltriethoxysilane) and continuing to knead the mixture for 2 minutes; then adding 15 parts of a filler (magnesium hydroxide) and 10 parts of modified glass fiber and kneading the mixture for 5 minutes; and finally adding 0.5 parts of an ultraviolet absorber (2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole) and 1 part of an antioxidant (antioxidant 168) and kneading the mixture for 2 minutes; granulating the obtained mixture through a twin-screw extruder and drying the mixture; adding the sheathing particles to a single-screw extruder and coating the mixture on the surface of a cable core (tinned copper conductor) with a polyvinyl chloride insulation layer to obtain a high-temperature resistant flame-retardant cable; Among them, the preparation process of modified glass fiber is: A1: Mix 8 parts of deionized water with 24 parts of anhydrous ethanol, adjust the pH to 4 with glacial acetic acid, then slowly add 0.2 parts of γ-methacryloxypropyltrimethoxysilane, stir for 30 minutes, then add 10 parts of glass fiber, raise the temperature to 30°C, and react for 60 minutes. After the reaction is complete, filter, separate, wash, and dry to obtain olefinic glass fiber; A2: (1) Slowly add 0.1 parts of potassium persulfate to 80 parts of deionized water at a temperature of 40°C, stirring while adding until the potassium persulfate is completely dissolved, and then naturally cool to 25°C to obtain an initiator solution; (2) Under a nitrogen atmosphere, mix 60 parts of olefin-modified glass fiber, 10 parts of functional monomer, 8 parts of methyl methacrylate, 3 parts of butyl acrylate, and 50 parts of ethanol, stir evenly, add part of the initiator solution, increase the temperature to 65°C, and react at a constant temperature for 1 hour, then continuously add the remaining initiator solution dropwise, and after the addition is completed, continue to react for 3 hours. After the reaction is completed, wash, let it stand in a constant temperature room at 25°C for 12 hours, and then dry at 70°C for 40 minutes to obtain modified glass fiber; Wherein, the preparation process of functional monomer is: S1: 10 parts of 3,5-diamino-1,2,4-triazole, 12 parts of triethylamine, and 80 parts of anhydrous tetrahydrofuran were mixed and stirred evenly. 15 parts of acryloyl chloride solution (25 wt%) were slowly added dropwise while maintaining the temperature at 0°C. After the addition was complete, the temperature was raised to room temperature and stirring was continued for 2 hours. After the reaction was completed, the mixture was filtered, concentrated, and purified to obtain intermediate A. S2: (1) 12 parts of diphenyl chlorophosphate was added to 30 parts of anhydrous tetrahydrofuran, stirred uniformly to obtain a diphenyl chlorophosphate solution; (2) 10 parts of 3-methoxy-4-hydroxybenzaldehyde, 8 parts of triethylamine, 30 parts of anhydrous tetrahydrofuran were mixed, stirred uniformly, and placed in an ice water bath to cool, controlling the temperature at 0°C, then slowly adding the diphenyl chlorophosphate solution, after the dropwise addition was completed, stirring for 30 min, then increasing the temperature to 60°C, reacting for 10 h under nitrogen protection, after the reaction was completed, naturally cooling to room temperature, and then treating to obtain an intermediate B; S3: 10 parts of the intermediate A, 15 parts of the intermediate B, 0.5 parts of p-toluenesulfonic acid, 60 parts of anhydrous ethanol were mixed, stirred uniformly, the temperature was increased to 40°C, and reacted for 8 h, after the reaction was completed, the temperature was cooled to room temperature, the solvent was removed by a rotary evaporator, and then washed and dried to obtain a functional monomer.

[0026] Example 2 A preparation method of a high-temperature-resistant flame-retardant cable, comprising the following steps: 10 parts of ethylene-vinyl acetate copolymer, 18 parts of ethylene-acrylate copolymer, and 18 parts of polyvinyl chloride resin are initially mixed at a low speed in a high-speed mixer, then added into a banbury mixer, and banburyed at 120°C for 3 min, then 4 parts of maleic anhydride grafted polyethylene and 2 parts of a coupling agent (γ-aminopropyl triethoxysilane) are continuously banburyed for 2 min, then 20 parts of a filler (magnesium hydroxide) and 12 parts of modified glass fiber are banburyed for 5 min, finally, 1 part of an ultraviolet absorber (2-(2'-hydroxy-3',5'-di-tert-pentylphenyl) benzotriazole) and 2 parts of an antioxidant (antioxidant 168) are banburyed for 2 min, the obtained mixing material is granulated by a double-screw extruder and dried, the sheath granules are added into a single-screw extruder, and coated on the surface of a cable core (tinned copper conductor) with a polyvinyl chloride insulation layer to obtain a high-temperature-resistant flame-retardant cable; The preparation process of the modified glass fiber is as follows: A1: 10 parts of deionized water and 30 parts of anhydrous ethanol are mixed, the pH is adjusted to 4.5 by using glacial acetic acid, then 0.3 parts of γ-methacryloyloxypropyl trimethoxysilane is slowly added, stirred for 40 min, then 12 parts of glass fiber is added, the temperature is increased to 40°C, and reacted for 90 min, after the reaction is completed, the reaction product is separated by suction filtration, washed, and dried to obtain an alkenyl glass fiber. A2: (1) 0.2 parts of potassium persulfate was slowly added into 100 parts of deionized water with a temperature of 50°C, stirring while adding, until the potassium persulfate was completely dissolved, and then naturally cooled to 25°C to obtain an initiator solution; (2) under a nitrogen atmosphere, 80 parts of alkenyl glass fiber, 15 parts of functional monomer, 10 parts of methyl methacrylate, 4 parts of butyl acrylate, 60 parts of ethanol were mixed, stirred uniformly, then part of the initiator solution was added, the temperature was raised to 70°C, and the reaction was carried out for 2h, then the remaining initiator solution was continuously added dropwise, after the dropwise addition was completed, the reaction was continued for 4h, after the reaction was completed, washing, constant temperature room standing for 12h at 25°C, then drying at 70°C for 50min, to obtain modified glass fiber; The preparation process of the functional monomer is: S1: 12 parts of 3,5-diamino-1,2,4-triazole, 15 parts of triethylamine, 100 parts of anhydrous tetrahydrofuran were mixed, stirred uniformly, the temperature was maintained at 5°C, 18 parts of acryloyl chloride solution (25wt%) was slowly added dropwise, after the dropwise addition was completed, the temperature was raised to room temperature, and the stirring was continued for 3h, after the reaction was completed, filtration, concentration, purification were carried out to obtain intermediate A; S2: (1) 15 parts of diphenyl chlorophosphate was added into 40 parts of anhydrous tetrahydrofuran, stirred uniformly to obtain a diphenyl chlorophosphate solution; (2) 12 parts of 3-methoxy-4-hydroxybenzaldehyde, 10 parts of triethylamine, 40 parts of anhydrous tetrahydrofuran were mixed, stirred uniformly, and placed in an ice water bath to cool, the temperature was controlled at 5°C, then the diphenyl chlorophosphate solution was slowly added dropwise, after the dropwise addition was completed, the stirring was continued for 40min, then the temperature was raised to 70°C, and the reaction was carried out for 12h under nitrogen protection, after the reaction was completed, the natural cooling to room temperature was carried out, and the post-treatment was carried out to obtain intermediate B; S3: 12 parts of intermediate A, 18 parts of intermediate B, 1 part of p-toluenesulfonic acid, 70 parts of anhydrous ethanol were mixed, stirred uniformly, the temperature was raised to 50°C, and the reaction was carried out for 10h, after the reaction was completed, the cooling to room temperature was carried out, the solvent was removed by a rotary evaporator, and washing, drying were carried out to obtain the functional monomer.

[0027] Example 3 A method for preparing a high-temperature resistant flame-retardant cable comprises the following steps: 9 parts of ethylene-vinyl acetate copolymer, 16.5 parts of ethylene-acrylate copolymer, and 16.5 parts of polyvinyl chloride resin are preliminarily mixed at a low speed in a high-speed mixer, then added to an internal mixer, and kneaded at 120°C for 3 minutes, then 3.5 parts of maleic anhydride grafted polyethylene and 1.5 parts of a coupling agent (γ-aminopropyltriethoxysilane) are added and kneaded for 2 minutes, and then 17.5 parts of a filler ( The mixture was granulated and dried by a twin-screw extruder. The sheath pellets were added into a single-screw extruder and coated on the surface of a cable core (tinned copper conductor) with a polyvinyl chloride insulation layer to obtain a high-temperature resistant flame-retardant cable. Among them, the preparation process of modified glass fiber is: A1: Mix 9 parts of deionized water with 27 parts of anhydrous ethanol, adjust the pH to 4.25 with glacial acetic acid, then slowly add 0.25 parts of γ-methacryloxypropyltrimethoxysilane and stir for 35 minutes. Then, add 11 parts of glass fiber and raise the temperature to 35°C. React for 75 minutes. After the reaction is complete, filter, separate, wash, and dry to obtain olefinic glass fiber. A2: (1) Slowly add 0.15 parts of potassium persulfate to 90 parts of deionized water at a temperature of 45°C, stirring while adding until the potassium persulfate is completely dissolved, and then naturally cool to 25°C to obtain an initiator solution; (2) Under a nitrogen atmosphere, mix 70 parts of olefin-modified glass fiber, 12.5 parts of functional monomer, 9 parts of methyl methacrylate, 3.5 parts of butyl acrylate, and 55 parts of ethanol, stir evenly, add part of the initiator solution, increase the temperature to 67.5°C, and react at a constant temperature for 1.5 hours. Then, continuously add the remaining initiator solution dropwise. After the addition is completed, continue to react for 3.5 hours. After the reaction is completed, wash, let it stand in a constant temperature room at 25°C for 12 hours, and then dry at 70°C for 45 minutes to obtain modified glass fiber; Wherein, the preparation process of functional monomer is: S1: Mix 11 parts of 3,5-diamino-1,2,4-triazole, 13.5 parts of triethylamine, and 90 parts of anhydrous tetrahydrofuran, stir evenly, maintain the temperature at 2.5°C, and slowly add dropwise 16.5 parts of acryloyl chloride solution (25 wt%). After the addition is complete, raise the temperature to room temperature and continue stirring for 2.5 hours. After the reaction is complete, filter, concentrate, and purify to obtain intermediate A; S2: (1) 13.5 parts of diphenyl chlorophosphate was added into 35 parts of anhydrous tetrahydrofuran, and stirred to obtain a diphenyl chlorophosphate solution; (2) 11 parts of 3-methoxy-4-hydroxybenzaldehyde, 9 parts of triethylamine, 35 parts of anhydrous tetrahydrofuran were mixed, stirred uniformly, and cooled in an ice water bath, the temperature was controlled at 2.5℃, then the diphenyl chlorophosphate solution was slowly added dropwise, after the dropwise addition was completed, the stirring was continued for 35 min, then the temperature was increased to 65℃, and the reaction was carried out under nitrogen protection for 11 h, after the reaction was completed, the natural cooling to room temperature was carried out, and then the post-treatment was carried out to obtain the intermediate B; S3: 11 parts of the intermediate A, 16.5 parts of the intermediate B, 0.75 parts of p-toluenesulfonic acid, 65 parts of anhydrous ethanol were mixed, stirred uniformly, the temperature was increased to 45℃, and the reaction was carried out for 9 h, after the reaction was completed, the cooling to room temperature was carried out, the solvent was removed by a rotary evaporator, and then the washing and drying were carried out to obtain the functional monomer.

[0028] Comparative Example 1: Without adding the modified glass fiber, the following was carried out: A preparation method of a high-temperature-resistant flame-retardant cable, comprising the following steps: 9 parts of ethylene-vinyl acetate copolymer, 16.5 parts of ethylene-acrylate copolymer, 16.5 parts of polyvinyl chloride resin were initially mixed in a high-speed mixer at a low speed, then were added into a banbury mixer, and were banburyed at 120℃ for 3 min, then 3.5 parts of maleic anhydride grafted polyethylene and 1.5 parts of a coupling agent (γ-aminopropyl triethoxysilane) were continuously banburyed for 2 min, then 17.5 parts of a filler (magnesium hydroxide) was banburyed for 5 min, finally 0.75 parts of an ultraviolet absorber (2-(2'-hydroxy-3',5'-di-tert-pentylphenyl) benzotriazole) and 1.5 parts of an antioxidant (antioxidant 168) were banburyed for 2 min, the obtained mixing material was granulated by a double-screw extruder and was dried, the sheath granules were added into a single-screw extruder, and were coated on the surface of a cable core (tinned copper conductor) with a polyvinyl chloride insulation layer to obtain the high-temperature-resistant flame-retardant cable.

[0029] Comparative Example 2: Without modifying the glass fiber, the following was carried out: A preparation method of a high-temperature-resistant flame-retardant cable, comprising the following steps: 9 parts of ethylene-vinyl acetate copolymer, 16.5 parts of ethylene-acrylate copolymer and 16.5 parts of polyvinyl chloride resin are initially mixed in a high-speed mixer at a low speed, then added into a banbury mixer, and banburyed at 120 DEG C for 3 min, then 3.5 parts of maleic anhydride grafted polyethylene and 1.5 parts of coupling agent (gamma-aminopropyl triethoxysilane) are continuously banburyed for 2 min, then 17.5 parts of filler (magnesium hydroxide) and 11 parts of glass fiber are banburyed for 5 min, finally 0.75 parts of ultraviolet absorber (2-(2'-hydroxy-3',5'-di-tert-pentylphenyl) benzotriazole) and 1.5 parts of antioxidant (antioxidant 168) are banburyed for 2 min, the obtained mixing material is granulated by a double-screw extruder and dried, the sheath granules are added into a single-screw extruder, and coated on the surface of a cable core (tinned copper conductor) with a polyvinyl chloride insulation layer to obtain the high-temperature-resistant flame-retardant cable.

[0030] Detection experiment: (1) The tensile strength of the cable sheath of the examples and the comparative examples is tested according to the standard GB / T 1040.3-2006; (2) The high temperature test of the cable sheath of the examples and the comparative examples is carried out according to the standard GB / T 2406.3-2022, and the oxygen index is determined; (3) The cable sheath prepared in the examples and the comparative examples is subjected to heat aging test (aging at 150 DEG C for 168 h), and then the tensile strength of the aged material is detected; The obtained data are shown in the following table:

[0031] Conclusion: The high-temperature-resistant flame-retardant cable of the application significantly improves the comprehensive performance of the cable by optimizing the sheath layer formula and modifying the preparation process of the glass fiber. The experimental data show that the tensile strength of examples 1-3 reaches 23.5 MPa, 25.8 MPa and 24.7 MPa respectively, which is much higher than that of comparative example 1 (15.3 MPa) without adding modified glass fiber and comparative example 2 (18.2 MPa) using unmodified glass fiber. In terms of flame retardant performance, the oxygen index of the examples is more than 30%, the highest being 34.5%, while the oxygen index of comparative examples 1 and 2 is only 26.3% and 28.7% respectively, indicating that the synergistic effect of modified glass fiber and functional monomer significantly enhances the flame retardant effect. In addition, after aging at 150 DEG C for 168 hours, the tensile strength of the examples remains at a high level (21.2-23.6 MPa), while that of comparative examples 1 and 2 decreases to 11.0 MPa and 15.4 MPa respectively, further verifying the advantage of the application in high-temperature resistance.

[0032] In summary, the application improves the mechanical properties and flame-retardant grade of the cable by modifying the glass fiber and introducing the functional monomer, significantly enhances the stability of the cable in high temperature environment, solves the deficiencies of the traditional flame-retardant cable in tensile strength, flame retardancy and high temperature resistance, and has important application value.

[0033] The above is only the preferred embodiment of the present application, and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high temperature resistant flame retardant cable, characterized in that: The cable comprises a cable core and an insulating layer and a sheath layer which sequentially cover the cable core from the inside out; the sheath layer comprises the following components: by weight, 8-10 parts of ethylene-vinyl acetate copolymer, 15-18 parts of ethylene-acrylate copolymer, 15-18 parts of polyvinyl chloride resin, 15-20 parts of filler, 10-12 parts of modified glass fiber, 3-4 parts of maleic anhydride grafted polyethylene, 0.5-1 part of ultraviolet absorber, 1-2 parts of antioxidant, and 1-2 parts of coupling agent.

2. A high temperature resistant flame retardant cable according to claim 1, characterized in that: The preparation process of the modified glass fiber is: A1: Mix deionized water and anhydrous ethanol, adjust the pH to 4-4.5 with glacial acetic acid, then slowly add γ-methacryloxypropyltrimethoxysilane and stir for 30-40 minutes. Then add glass fiber and raise the temperature to 30-40°C. React for 60-90 minutes. After the reaction is complete, filter, separate, wash, and dry to obtain olefinic glass fiber. A2: (1) Slowly add potassium persulfate into deionized water at a temperature of 40-50°C, stirring while adding until the potassium persulfate is completely dissolved, and then naturally cool to 25°C to obtain an initiator solution; (2) Under a protective atmosphere, mix the olefinated glass fiber, functional monomer, methyl methacrylate, butyl acrylate, and ethanol, stir evenly, add part of the initiator solution, increase the temperature to 65-70°C, and react at a constant temperature for 1-2 hours. Then, continuously add the remaining initiator solution dropwise. After the addition is completed, continue to react for 3-4 hours. After the reaction is completed, wash, let it stand in a constant temperature room at 25°C for 12 hours, and then dry at 70°C for 40-50 minutes to obtain modified glass fiber.

3. A high temperature resistant flame retardant cable according to claim 2, characterized in that: The raw materials for preparing the olefinic glass fiber include the following components: by weight, 8-10 parts of deionized water, 24-30 parts of anhydrous ethanol, 0.2-0.3 parts of gamma-methacryloxypropyltrimethoxysilane, and 10-12 parts of glass fiber.

4. The high temperature resistant flame retardant cable according to claim 2, characterized in that: The raw materials of the initiator solution include the following components: by weight, 0.1-0.2 parts of potassium persulfate, 80-100 parts of deionized water, 60-80 parts of olefinic glass fiber, 10-15 parts of functional monomer, 8-10 parts of methyl methacrylate, 3-4 parts of butyl acrylate, and 50-60 parts of ethanol.

5. The high temperature resistant flame retardant cable according to claim 2, characterized in that: The preparation process of the functional monomer is as follows: S1: Mix 3,5-diamino-1,2,4-triazole, triethylamine, and anhydrous tetrahydrofuran, stir evenly, maintain the temperature at 0-5°C, slowly add acryloyl chloride solution dropwise, raise the temperature to room temperature after the addition is complete, continue stirring for 2-3 hours, filter, concentrate, and purify to obtain intermediate A; S2: (1) Add diphenyl chlorophosphate to anhydrous tetrahydrofuran and stir evenly to obtain a diphenyl chlorophosphate solution; (2) Mix 3-methoxy-4-hydroxybenzaldehyde, triethylamine, and anhydrous tetrahydrofuran, stir evenly, and place in an ice-water bath to cool, control the temperature at 0-5°C, and then slowly add the diphenyl chlorophosphate solution dropwise. After the addition is completed, continue stirring for 30-40 minutes, then increase the temperature to 60-70°C, and react under nitrogen protection for 10-12 hours. After the reaction is completed, naturally cool to room temperature, and post-treat to obtain intermediate B; S3: Mix intermediate A, intermediate B, p-toluenesulfonic acid and anhydrous ethanol, stir evenly, increase the temperature to 40-50°C, react for 8-10 hours, and after the reaction is completed, cool to room temperature, remove the solvent using a rotary evaporator, wash and dry to obtain a functional monomer.

6. The high temperature resistant flame retardant cable according to claim 5, characterized in that: The raw materials for preparing the intermediate A include the following components: 10-12 parts by weight of 3,5-diamino-1,2,4-triazole, 12-15 parts of triethylamine, 80-100 parts of anhydrous tetrahydrofuran, and 15-18 parts of acryloyl chloride solution; wherein the concentration of the acryloyl chloride solution is 25 wt%.

7. The high temperature resistant flame retardant cable according to claim 5, characterized in that: The raw materials for preparing the intermediate B retain the following components: by weight, 12-15 parts of diphenyl chlorophosphate, 60-80 parts of anhydrous tetrahydrofuran, 10-12 parts of 3-methoxy-4-hydroxybenzaldehyde, and 8-10 parts of triethylamine.

8. The high temperature resistant flame retardant cable according to claim 5, characterized in that: The raw materials for preparing the functional monomer include the following components: by weight, 10-12 parts of intermediate A, 15-18 parts of intermediate B, 0.5-1 part of p-toluenesulfonic acid, and 60-70 parts of anhydrous ethanol.

9. The high temperature resistant flame retardant cable according to claim 1, characterized in that: The filler includes one or more of aluminum hydroxide, magnesium hydroxide, and magnesium oxide.

10. The high temperature resistant flame retardant cable according to claim 1, characterized in that: The antioxidant is antioxidant 168; the ultraviolet absorber is 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole; and the coupling agent is gamma-aminopropyltriethoxysilane.

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