A copper-clad aluminum power cable

Abstract

The invention relates to the field of power cables, and in particular to a copper-clad aluminum power cable. A modified filler is added to the raw material of an outer sheath layer of the copper-clad aluminum power cable, and the special structure of the modified filler solves the problem that a flame retardant in the outer sheath of the existing copper-clad aluminum power cable is easy to precipitate during the aging process. In addition, due to the presence of nitrogen and phosphorus elements in the modified filler, it can also show a good flame retardant effect. At the same time, due to the ceramicization of organic silicon microspheres in the modified filler when a fire occurs, it can be combined with boron nitride in the modified filler and a carbon layer formed by an expanding flame retardant, thereby forming a protective layer to isolate the damage caused by the fire to the shielding layer, thereby ensuring the normal operation of the power cable in the fire.

Description

Technical Field

[0001] The invention relates to the field of power cables, and in particular to a copper-clad aluminum power cable. Background Art

[0002] Copper clad aluminum power cable generally consists of a copper clad aluminum wire core, a shielding layer and an outer sheath layer from the inside to the outside. The outer sheath layer, as the main part in contact with the outside world, is currently mainly made of cross-linked polyethylene as the raw material through extrusion. However, due to the poor flame retardant properties of cross-linked polyethylene materials, in the event of a fire, the flame will spread along the cable and cause the fire to continue to expand, leading to secondary fire accidents. Currently, the main choice is to add flame retardants during the extrusion process of the cable to improve the flame retardant ability of the outer sheath layer.

[0003] At present, the nitrogen-phosphorus composite intumescent flame retardant is mainly used on the market. It has excellent flame retardant properties. Often a small amount of addition can greatly improve the flame retardant ability of the cable outer sheath layer. However, the intumescent flame retardant has the problem of easy precipitation during use, which will cause the flame retardant ability of the cable outer sheath layer to decrease, thereby affecting the service life of the cable. At the same time, due to the use scenario of copper-clad aluminum power cables, they are required to have a certain fire resistance to ensure that they can still maintain normal use for a certain period of time when a fire occurs. Summary of the invention

[0004] The purpose of the present invention is to provide a copper-clad aluminum power cable, which solves the problem that the flame retardant of the outer sheath of the existing copper-clad aluminum power cable is easy to precipitate during the aging process. At the same time, by adding modified fillers to the raw material blending masterbatch of the cable outer sheath layer, the outer sheath layer forms a protective layer when a fire occurs, thereby ensuring the normal operation of the power cable.

[0005] The object of the present invention can be achieved by the following technical scheme: a copper-clad aluminum power cable, which comprises a copper-clad aluminum wire core, a shielding layer and an outer sheath layer from the inside to the outside, wherein the outer sheath layer is made of a blended masterbatch, and the blended masterbatch is made by the following steps: weighing the following raw materials in parts by weight: 60-70 parts of low-density polyethylene, 10-15 parts of high-density polyethylene, 1-3 parts of a peroxide cross-linking agent, 0.8-1 parts of a lubricant and 6-8 parts of a modified filler, mixing the low-density polyethylene, the high-density polyethylene, the peroxide cross-linking agent, the lubricant and the modified filler, adding the mixture to a twin-screw extruder, extruding and granulating, and making a blended masterbatch;

[0006] The copper-clad aluminum power cable is prepared by the following steps: passing the copper-clad aluminum wire into a wire drawing machine, drawing the wire, annealing, and twisting the wire to obtain a copper-clad aluminum wire core, wrapping a mica tape around the outside of the copper-clad aluminum wire core to form a shielding layer, and then extruding a blended masterbatch as a raw material outside the shielding layer to form an outer sheath layer, steam cross-linking, cooling in a water tank, and air drying in a drying machine to obtain a copper-clad aluminum power cable;

[0007] The modified filler is prepared by the following steps:

[0008] Step A1: boron nitride and sodium hydroxide solution are mixed, and the mixture is reacted for 16-18 hours at a stirring rate of 200-300 rpm and a temperature of 120° C. to obtain activated boron nitride; the activated boron nitride, 3-glycidyloxypropyltrimethoxysilane and ethanol solution are mixed, ultrasonically dispersed for 20-30 minutes, and the mixture is reacted for 6-8 hours at a stirring rate of 120-150 rpm and a temperature of 60° C.; propargylamine is then added, and the reaction is continued for 24 hours to obtain modified boron nitride;

[0009] The molar concentration of the sodium hydroxide solution is 5 mol / L, the amount ratio of boron nitride to the sodium hydroxide solution is 2-3 g: 60-80 mL, the volume fraction of the ethanol solution is 80%, and the amount ratio of activated boron nitride, 3-glycidyloxypropyltrimethoxysilane, ethanol solution and propargylamine is 2-2.5 g: 0.008-0.01 mol: 60-70 mL: 0.008-0.01 mol;

[0010] During the reaction, boron nitride is added to a sodium hydroxide solution to activate its surface to generate hydroxyl groups. In an ethanol solution, the methoxy groups in 3-glycidyloxypropyltrimethoxysilane are hydrolyzed and react and condense with the hydroxyl groups in the activated boron nitride to introduce epoxy groups. The epoxy groups then react with the amino groups in propargylamine to obtain modified boron nitride containing alkynyl groups.

[0011] Step A2: Modified boron nitride, composite silicon microspheres, copper sulfate and N,N-dimethylformamide are mixed, ultrasonically dispersed for 5-10 minutes, stirred and added with pentamethyldiethylenetriamine under nitrogen protection at a stirring rate of 120-150 rpm and a temperature of 30°C, reacted for 24 hours, then heated to 50°C and added with iodoethane, and continued to react for 24 hours to obtain composite boron nitride;

[0012] The dosage ratio of modified boron nitride, composite silicon microspheres, copper sulfate, pentamethyldiethylenetriamine and ethyl iodide is 2-2.5 g: 1.2-1.5 g: 12-14 g: 10-12 mL: 0.008-0.01 mol;

[0013] During the reaction, under the action of copper sulfate and pentamethyldiethylenetriamine as catalysts, the alkynyl group in the modified boron nitride reacts with the azide group in the composite silicon microspheres to form a triazole structure, which then reacts with iodine in iodoethane to form a quaternary ammonium structure to obtain composite boron nitride.

[0014] Step A3: Mixing composite boron nitride and ethanol, stirring at a rate of 150-200 rpm and a temperature of 5° C., adding dimethyl phosphate, heating to room temperature, and reacting for 4-6 hours to obtain a modified filler;

[0015] The dosage ratio of composite boron nitride, ethanol and dimethyl phosphate is: 3-3.5g: 60-80mL: 0.4-0.5g;

[0016] During the reaction, due to the presence of quaternary ammonium structure in the composite boron nitride, its surface carries positive charge, which combines with dimethyl phosphate by electrostatic action to obtain a modified filler.

[0017] The composite silicon microspheres are prepared by the following steps:

[0018] Step B1: dimethyldimethoxysilane, phenyltrimethoxysilane and deionized water are mixed, stirred at a stirring rate of 150-200 rpm, and ammonia water is added at room temperature, and the mixture is reacted for 2-3 hours, and then 3-aminopropyltrimethoxysilane is added, and the reaction is continued for 1-1.5 hours, and then spray-dried to obtain aminosilicon microspheres;

[0019] The mass fraction of ammonia water is 25%, and the dosage ratio of dimethyldimethoxysilane, phenyltrimethoxysilane, deionized water, ammonia water and 3-aminopropyltrimethoxysilane is 0.04-0.05mol: 0.045-0.055mol: 280-300mL: 20-24mL: 0.01-0.012mol;

[0020] During the reaction, under alkaline conditions, the methoxy groups in dimethyldimethoxysilane and phenyltrimethoxysilane undergo hydrolysis and condensation to form an organosilicon microsphere structure, and then 3-aminopropyltrimethoxysilane is added. 3-aminopropyltrimethoxysilane also undergoes hydrolysis and condensation with the hydroxyl groups on the surface of the microspheres to obtain aminosilicon microspheres with amino active groups on the surface.

[0021] Step B2: p-bromomethylbenzoic acid, sodium azide and N,N-dimethylformamide are mixed, and the mixture is reacted for 12-14 hours at a stirring rate of 100-150 rpm and a temperature of 50°C to obtain intermediate a. Intermediate a, aminosilicon microspheres and N,N-dimethylformamide are mixed, and the mixture is stirred at a stirring rate of 60-80 rpm and room temperature, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added, and the mixture is reacted for 24 hours to obtain modified silicon microspheres.

[0022] The ratio of p-bromomethylbenzoic acid to sodium azide is 0.01-0.011 mol: 0.014-0.015 mol, and the ratio of intermediate a, aminosilicon microspheres, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide is 0.01-0.011 mol: 2-3 g: 0.02-0.021 mol: 0.02-0.023 mol;

[0023] During the reaction, bromine in p-bromomethylbenzoic acid is azidated under the action of sodium azide to form an azide group to obtain an intermediate a. Then, under the conditions of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide as catalysts, the carboxyl group in the intermediate a reacts with the amino group in the aminosilicon microspheres to form an amide group to obtain modified silicon microspheres.

[0024] Step B3: the modified silicon microspheres and the ethylene glycol solution are mixed, ultrasonically dispersed for 10-15 minutes, stirred at a stirring rate of 100-120 rpm and a temperature of 130° C., and chloroplatinic acid solution is added, and reacted for 3-4 hours to obtain composite silicon microspheres;

[0025] The volume fraction of ethylene glycol solution is 60%, the mass fraction of chloroplatinic acid solution is 16%, and the dosage ratio of modified silica microspheres, ethanol solution and chloroplatinic acid solution is 1.2-1.5g:100-110mL:1-1.2mL;

[0026] During the reaction, due to the presence of azide groups in the modified silicon microspheres, platinum ions can be adsorbed on the modified silicon microspheres. At the same time, due to the reducing properties of the polyhydroxyl groups in the ethylene glycol solution, platinum is in-situ reduced and loaded on the modified silicon microspheres to obtain composite silicon microspheres.

[0027] The lubricant includes one or more of polyethylene wax, stearic acid, and polypropylene wax; the peroxide cross-linking agent includes one or two of dicumyl peroxide and di-tert-butyl peroxide.

[0028] Beneficial effects of the invention: The invention discloses a copper-clad aluminum power cable, which solves the problem that the flame retardant of the outer sheath of the existing copper-clad aluminum power cable is easy to precipitate during the aging process, and at the same time, by adding a modified filler to the raw material blending masterbatch of the cable outer sheath layer, the outer sheath layer forms a protective layer when a fire occurs, thereby ensuring the normal operation of the power cable; since there are triazole groups in the modified filler and phosphate groups are adsorbed by electrostatic action, these nitrogen and phosphorus elements can form an expansion flame retardant system and exert good flame retardant performance, and since the modified filler has a boron nitride sheet structure as its main body and is connected to composite silicon microspheres through triazole groups, a special structure is formed, thereby avoiding the modified filler The material precipitates from the substrate during the aging process. Under the high temperature conditions of the fire, since the surface of the modified silicon microspheres is loaded with nano-platinum, these platinums can cooperate with the phosphoric acid decomposed by the phosphate group under heat, which can promote the ceramicization of the silicon microspheres under high temperature conditions. Moreover, since the silicon microspheres are connected to the modified boron nitride, and the nitrogen-phosphorus expansion flame retardant system can also promote the formation of a dense carbon layer, these three are combined to form a continuous isolation layer when a fire occurs, thereby preventing the cable shielding layer from being harmed by the fire, thereby ensuring the normal operation of the line. At the same time, due to the presence of the triazole group, it can cooperate with the platinum loaded on the silicon microspheres, thereby avoiding the oxidation of platinum during the aging process, thereby extending the service life of the power cable. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Embodiment 1 A copper-clad aluminum power cable comprises, from the inside to the outside, a copper-clad aluminum core, a shielding layer and an outer sheath layer, wherein the outer sheath layer is made of a blended masterbatch, and the blended masterbatch is made by the following steps: weigh the following raw materials in parts by weight: 60 parts of commercially available AT6101 low-density polyethylene, 10 parts of commercially available DGDK-3364 high-density polyethylene, 1 part of di-tert-butyl peroxide, 0.8 parts of polyethylene wax and 6 parts of modified filler, mix the low-density polyethylene, high-density polyethylene, peroxide cross-linking agent, lubricant and modified filler and add them to a twin-screw extruder, extrude and granulate, and make a blended masterbatch;

[0031] The copper-clad aluminum power cable is prepared by the following steps: passing the copper-clad aluminum wire into a wire drawing machine, drawing the wire, annealing, and twisting the wire to obtain a copper-clad aluminum wire core, wrapping a mica tape with a product specification of 45 produced by Ningjin County Haoxin New Material Technology Co., Ltd. on the outside of the copper-clad aluminum wire core to form a shielding layer, and then extruding a blended masterbatch as a raw material on the outside of the shielding layer to form an outer sheath layer, steam cross-linking, water tank cooling, and drying in a drying machine to obtain a copper-clad aluminum power cable;

[0032] The modified filler is prepared by the following steps:

[0033] Step A1: commercially available 30 μm boron nitride and sodium hydroxide solution are mixed, and the mixture is reacted for 16 hours at a stirring rate of 200 rpm and a temperature of 120° C. to obtain activated boron nitride; the activated boron nitride, 3-glycidyloxypropyltrimethoxysilane and ethanol solution are mixed, ultrasonically dispersed for 20 minutes, and the mixture is reacted for 6 hours at a stirring rate of 120 rpm and a temperature of 60° C.; propargylamine is then added, and the reaction is continued for 24 hours to obtain modified boron nitride;

[0034] The molar concentration of the sodium hydroxide solution is 5 mol / L, the amount ratio of boron nitride to the sodium hydroxide solution is 2 g: 60 mL, the volume fraction of the ethanol solution is 80%, and the amount ratio of activated boron nitride, 3-glycidyloxypropyltrimethoxysilane, ethanol solution and propargylamine is 2 g: 0.008 mol: 60 mL: 0.008 mol;

[0035] Step A2: Modified boron nitride, composite silicon microspheres, copper sulfate and N,N-dimethylformamide were mixed, ultrasonically dispersed for 5 minutes, stirred and added with pentamethyldiethylenetriamine under nitrogen protection at a stirring rate of 120 rpm and a temperature of 30°C, reacted for 24 hours, then heated to 50°C and added with iodoethane, and continued to react for 24 hours to obtain composite boron nitride;

[0036] The dosage ratio of modified boron nitride, composite silicon microspheres, copper sulfate, pentamethyldiethylenetriamine and ethyl iodide is 2g:1.2g:12g:10mL:0.008mol;

[0037] Step A3: Mixing composite boron nitride and ethanol, stirring at a stirring rate of 150 rpm and a temperature of 5° C., adding dimethyl phosphate, heating to room temperature, and reacting for 4 hours to obtain a modified filler;

[0038] The dosage ratio of composite boron nitride, ethanol and dimethyl phosphate is 3g:60mL:0.4g;

[0039] Composite silicon microspheres are prepared by the following steps:

[0040] Step B1: dimethyldimethoxysilane, phenyltrimethoxysilane and deionized water were mixed, stirred at a stirring rate of 150 rpm, and ammonia water was added at room temperature, and the mixture was reacted for 2 h, and then 3-aminopropyltrimethoxysilane was added, and the reaction was continued for 1 h, and the mixture was spray-dried to obtain aminosilicon microspheres;

[0041] The mass fraction of ammonia water is 25%, and the dosage ratio of dimethyldimethoxysilane, phenyltrimethoxysilane, deionized water, ammonia water and 3-aminopropyltrimethoxysilane is 0.04 mol: 0.045 mol: 280 mL: 20 mL: 0.01 mol;

[0042] Step B2: p-Bromomethylbenzoic acid, sodium azide and N,N-dimethylformamide were mixed, and the mixture was reacted for 12 hours at a stirring rate of 100 rpm and a temperature of 50°C to obtain intermediate a. Intermediate a, aminosilicon microspheres and N,N-dimethylformamide were mixed, and the mixture was stirred at a stirring rate of 60 rpm and room temperature, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide were added, and the mixture was reacted for 24 hours to obtain modified silicon microspheres.

[0043] The ratio of p-bromomethylbenzoic acid to sodium azide is 0.01 mol: 0.014 mol, and the ratio of intermediate a, aminosilicon microspheres, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide is 0.01 mol: 2 g: 0.02 mol: 0.02 mol;

[0044] Step B3: the modified silicon microspheres and the ethylene glycol solution were mixed, ultrasonically dispersed for 10 min, stirred at a stirring rate of 100 rpm and a temperature of 130° C., and chloroplatinic acid solution was added, and reacted for 3 h to obtain composite silicon microspheres;

[0045] The volume fraction of ethylene glycol solution is 60%, the mass fraction of chloroplatinic acid solution is 16%, and the dosage ratio of modified silica microspheres, ethanol solution and chloroplatinic acid solution is 1.2g:100mL:1mL.

[0046] Embodiment 2 A copper-clad aluminum power cable comprises, from the inside to the outside, a copper-clad aluminum core, a shielding layer and an outer sheath layer, wherein the outer sheath layer is made of a blended masterbatch, and the blended masterbatch is made by the following steps: weigh the following raw materials in parts by weight: 70 parts of commercially available AT6101 low-density polyethylene, 15 parts of commercially available DGDK-3364 high-density polyethylene, 3 parts of di-tert-butyl peroxide, 1 part of polyethylene wax and 6 parts of modified fillers, mix the low-density polyethylene, high-density polyethylene, peroxide cross-linking agent, lubricant and modified filler and add them to a twin-screw extruder, extrude and granulate to obtain a blended masterbatch;

[0047] Copper clad aluminum power cable is made by the following steps:

[0048] The copper-clad aluminum wire is passed through a wire drawing machine, drawn, annealed, and twisted to obtain a copper-clad aluminum wire core, a mica tape with a product specification of 45 produced by Ningjin County Haoxin New Material Technology Co., Ltd. is wrapped around the outside of the copper-clad aluminum wire core to form a shielding layer, and then a blended masterbatch is used as a raw material to extrude the outside of the shielding layer to form an outer sheath layer, steam cross-linked, cooled in a water tank, and air-dried in a drying machine to obtain a copper-clad aluminum power cable;

[0049] The modified filler is prepared by the following steps:

[0050] Step A1: Mix commercially available 30 μm boron nitride and sodium hydroxide solution, react for 16 hours at a stirring rate of 300 rpm and a temperature of 120° C. to obtain activated boron nitride; mix activated boron nitride, 3-glycidyloxypropyltrimethoxysilane and ethanol solution, ultrasonically disperse for 20 minutes, react for 8 hours at a stirring rate of 150 rpm and a temperature of 60° C., then add propargylamine and continue to react for 24 hours to obtain modified boron nitride;

[0051] The molar concentration of the sodium hydroxide solution is 5 mol / L, the amount ratio of boron nitride to the sodium hydroxide solution is 3 g: 60 mL, the volume fraction of the ethanol solution is 80%, and the amount ratio of activated boron nitride, 3-glycidyloxypropyltrimethoxysilane, ethanol solution and propargylamine is 2 g: 0.008 mol: 70 mL: 0.008 mol;

[0052] Step A2: Modified boron nitride, composite silicon microspheres, copper sulfate and N,N-dimethylformamide were mixed, ultrasonically dispersed for 10 minutes, stirred and added with pentamethyldiethylenetriamine under nitrogen protection at a stirring rate of 120 rpm and a temperature of 30°C, reacted for 24 hours, then heated to 50°C and added with iodoethane, and continued to react for 24 hours to obtain composite boron nitride;

[0053] The dosage ratio of modified boron nitride, composite silicon microspheres, copper sulfate, pentamethyldiethylenetriamine and iodine ethane is 2g:1.5g:14g:10mL:0.01mol;

[0054] Step A3: Mixing composite boron nitride and ethanol, stirring at a stirring rate of 200 rpm and a temperature of 5° C., adding dimethyl phosphate, heating to room temperature, and reacting for 4 hours to obtain a modified filler;

[0055] The dosage ratio of composite boron nitride, ethanol and dimethyl phosphate is 3.5g:60mL:0.5g;

[0056] Composite silicon microspheres are prepared by the following steps:

[0057] Step B1: dimethyldimethoxysilane, phenyltrimethoxysilane and deionized water were mixed, stirred at a stirring rate of 150 rpm, and ammonia water was added at room temperature, and the mixture was reacted for 3 h, and then 3-aminopropyltrimethoxysilane was added, and the reaction was continued for 1.5 h, and the mixture was spray-dried to obtain aminosilicon microspheres;

[0058] The mass fraction of ammonia water is 25%, and the dosage ratio of dimethyldimethoxysilane, phenyltrimethoxysilane, deionized water, ammonia water and 3-aminopropyltrimethoxysilane is 0.04 mol: 0.045 mol: 300 mL: 20 mL: 0.012 mol;

[0059] Step B2: p-Bromomethylbenzoic acid, sodium azide and N,N-dimethylformamide were mixed, and the mixture was reacted for 14 hours at a stirring rate of 100 rpm and a temperature of 50°C to obtain intermediate a. Intermediate a, aminosilicon microspheres and N,N-dimethylformamide were mixed, and the mixture was stirred at a stirring rate of 80 rpm and room temperature, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide were added, and the mixture was reacted for 24 hours to obtain modified silicon microspheres.

[0060] The ratio of p-bromomethylbenzoic acid to sodium azide is 0.011 mol: 0.014 mol, and the ratio of intermediate a, aminosilicon microspheres, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide is 0.011 mol: 3 g: 0.02 mol: 0.02 mol;

[0061] Step B3: the modified silicon microspheres and the ethylene glycol solution were mixed, ultrasonically dispersed for 15 minutes, stirred at a stirring rate of 120 rpm and a temperature of 130° C., and chloroplatinic acid solution was added, and reacted for 3 hours to obtain composite silicon microspheres;

[0062] The volume fraction of ethylene glycol solution is 60%, the mass fraction of chloroplatinic acid solution is 16%, and the dosage ratio of modified silica microspheres, ethanol solution and chloroplatinic acid solution is 1.2g:110mL:1mL.

[0063] Embodiment 3 A copper-clad aluminum power cable comprises, from the inside to the outside, a copper-clad aluminum core, a shielding layer and an outer sheath layer, wherein the outer sheath layer is made of a blended masterbatch, and the blended masterbatch is made by the following steps: weigh the following raw materials in parts by weight: 70 parts of commercially available AT6101 low-density polyethylene, 15 parts of commercially available DGDK-3364 high-density polyethylene, 3 parts of di-tert-butyl peroxide, 1 part of polyethylene wax and 8 parts of modified filler, mix the low-density polyethylene, high-density polyethylene, peroxide cross-linking agent, lubricant and modified filler and add them to a twin-screw extruder, extrude and granulate to obtain a blended masterbatch;

[0064] The copper-clad aluminum power cable is prepared by the following steps: passing the copper-clad aluminum wire into a wire drawing machine, drawing the wire, annealing, and twisting the wire to obtain a copper-clad aluminum wire core, wrapping a mica tape with a product specification of 45 produced by Ningjin County Haoxin New Material Technology Co., Ltd. on the outside of the copper-clad aluminum wire core to form a shielding layer, and then extruding a blended masterbatch as a raw material on the outside of the shielding layer to form an outer sheath layer, steam cross-linking, water tank cooling, and drying in a drying machine to obtain a copper-clad aluminum power cable;

[0065] The modified filler is prepared by the following steps:

[0066] Step A1: Mix commercially available 30 μm boron nitride and sodium hydroxide solution, react for 18 hours at a stirring rate of 300 rpm and a temperature of 120° C. to obtain activated boron nitride; mix activated boron nitride, 3-glycidyloxypropyltrimethoxysilane and ethanol solution, ultrasonically disperse for 30 minutes, react for 8 hours at a stirring rate of 150 rpm and a temperature of 60° C., then add propargylamine and continue to react for 24 hours to obtain modified boron nitride;

[0067] The molar concentration of the sodium hydroxide solution is 5 mol / L, the amount ratio of boron nitride to the sodium hydroxide solution is 3 g:80 mL, the volume fraction of the ethanol solution is 80%, and the amount ratio of activated boron nitride, 3-glycidyloxypropyltrimethoxysilane, ethanol solution and propargylamine is 2.5 g:0.01 mol:65 mL:0.01 mol;

[0068] Step A2: Modified boron nitride, composite silicon microspheres, copper sulfate and N,N-dimethylformamide were mixed, ultrasonically dispersed for 10 minutes, stirred and added with pentamethyldiethylenetriamine under nitrogen protection at a stirring rate of 150 rpm and a temperature of 30°C, reacted for 24 hours, then heated to 50°C and added with ethyl iodide, and continued to react for 24 hours to obtain composite boron nitride;

[0069] The dosage ratio of modified boron nitride, composite silicon microspheres, copper sulfate, pentamethyldiethylenetriamine and ethyl iodide is 2.5 g: 1.5 g: 14 g: 12 mL: 0.01 mol;

[0070] Step A3: Mixing composite boron nitride and ethanol, stirring at a stirring rate of 200 rpm and a temperature of 5° C., adding dimethyl phosphate, heating to room temperature, and reacting for 6 hours to obtain a modified filler;

[0071] The dosage ratio of composite boron nitride, ethanol and dimethyl phosphate is 3.5g:80mL:0.5g;

[0072] Composite silicon microspheres are prepared by the following steps:

[0073] Step B1: dimethyldimethoxysilane, phenyltrimethoxysilane and deionized water were mixed, stirred at a stirring rate of 200 rpm, and ammonia water was added at room temperature, and the mixture was reacted for 3 hours, and then 3-aminopropyltrimethoxysilane was added, and the reaction was continued for 1.5 hours, and then spray-dried to obtain aminosilicon microspheres;

[0074] The mass fraction of ammonia water is 25%, and the dosage ratio of dimethyldimethoxysilane, phenyltrimethoxysilane, deionized water, ammonia water and 3-aminopropyltrimethoxysilane is 0.05mol: 0.055mol: 300mL: 24mL: 0.012mol;

[0075] Step B2: p-Bromomethylbenzoic acid, sodium azide and N,N-dimethylformamide were mixed, and the mixture was reacted for 14 hours at a stirring rate of 150 rpm and a temperature of 50°C to obtain intermediate a. Intermediate a, aminosilicon microspheres and N,N-dimethylformamide were mixed, and the mixture was stirred at a stirring rate of 80 rpm and room temperature, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide were added, and the mixture was reacted for 24 hours to obtain modified silicon microspheres.

[0076] The ratio of p-bromomethylbenzoic acid to sodium azide is 0.011 mol: 0.014-0.015 mol, and the ratio of intermediate a, aminosilicon microspheres, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide is 0.011 mol: 3 g: 0.021 mol: 0.023 mol;

[0077] Step B3: the modified silicon microspheres and the ethylene glycol solution were mixed, ultrasonically dispersed for 15 minutes, stirred at a stirring rate of 120 rpm and a temperature of 130° C., and chloroplatinic acid solution was added, and reacted for 4 hours to obtain composite silicon microspheres;

[0078] The volume fraction of ethylene glycol solution is 60%, the mass fraction of chloroplatinic acid solution is 16%, and the dosage ratio of modified silica microspheres, ethanol solution and chloroplatinic acid solution is 1.5g:110mL:1.2mL.

[0079] Comparative Example 1 Compared with Example 3, this comparative example is different in that propargylamine in the preparation process of the modified filler in Example 3 is replaced by propylamine, and the other steps are the same.

[0080] Comparative Example 2 Compared with Example 3, this comparative example is to remove ethyl iodide in the preparation process of the modified filler in Example 3, and the other steps are the same.

[0081] Comparative Example 3 Compared with Example 3, this comparative example is different in that the composite silicon microspheres in the blended masterbatch of Example 3 are replaced with modified silicon microspheres, and the other steps are the same.

[0082] Comparative Example 4 Compared with Example 3, this comparative example replaces the modified filler in Example 3 with a mixture of boron nitride and BUDIT 667 intumescent flame retardant, wherein the amount ratio of boron nitride to BUDIT 667 intumescent flame retardant is 3.5g:0.5g, and other steps are the same.

[0083] Take the copper clad aluminum power cables prepared in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4, peel off the outer sheath layer to make samples, refer to GB / T 2406.2-2009, make them into 80mm×10mm samples, use a limiting oxygen index instrument to test the samples, and test their limiting oxygen index. Refer to GB / T 2408-2021, make them into 125mm×13mm samples, use a horizontal vertical combustion tester to perform a vertical combustion test on them, and evaluate their combustion levels. The samples are heat aged at a temperature of 135°C for 7d, and then their limiting oxygen index is tested, and their limiting oxygen index retention rate is calculated to evaluate their flame retardant properties after heat aging. Refer to GB / T 19216.21-2003, copper clad aluminum power cable is made into 1200mm test sample, and its qualification is judged by observing whether the bulb goes out after ignition and cooling. The initial ignition time is 90min, and the cooling time is 15min. If the bulb does not go out, the test is qualified. The ignition time is increased by 10min, and the cooling time remains unchanged until the bulb goes out, which means the test is unqualified. The ignition time when the bulb goes out is used as the judgment of its fire resistance performance. The test results are shown in Table 1:

[0084]

[0085] It can be seen from the test results in the table shown that when Example 1, Example 2 and Example 3 are compared with Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4, in Comparative Example 1, propargylamine in the preparation process of the modified filler in Example 3 is replaced with propylamine. Due to the lack of alkynyl groups, triazole and special structures cannot be formed, thereby affecting the flame retardant and fire resistant properties of the outer sheath layer, and the heat aging resistance also decreases to a certain extent. In Comparative Example 2, ethyl iodide is removed during the preparation process of the modified filler in Example 3. Due to the lack of quaternary ammonium structure, phosphate groups cannot be combined, and an intumescent flame retardant system cannot be formed, resulting in a significant decrease in its flame retardant properties. At the same time, its fire resistance decreases to a certain extent. In Comparative Example 3, the composite silicon microspheres of the blended masterbatch in Example 3 are replaced with modified silicon microspheres. Due to the lack of platinum loading, it cannot catalyze the ceramicization of the organosilicon microspheres and cannot ensure its fire resistance. In Comparative Example 4, the modified filler in Example 3 is replaced with a mixture of boron nitride and BUDIT 667 intumescent flame retardant, wherein boron nitride and BUDIT The dosage ratio of 667 intumescent flame retardant is 3.5g:0.5g. Due to the lack of special structure, its heat aging resistance and precipitation ability are greatly reduced.

[0086] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0087] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A copper-clad aluminum power cable, characterized in that: From the inside to the outside, the copper-clad aluminum wire core, the shielding layer and the outer sheath layer are arranged in sequence, wherein the outer sheath layer is made of a blended masterbatch, and the blended masterbatch is made by the following steps: weighing the following raw materials in parts by weight: 60-70 parts of low-density polyethylene, 10-15 parts of high-density polyethylene, 1-3 parts of a peroxide cross-linking agent, 0.8-1 parts of a lubricant and 6-8 parts of a modified filler, mixing the low-density polyethylene, the high-density polyethylene, the peroxide cross-linking agent, the lubricant and the modified filler, adding the mixture to a twin-screw extruder, extruding and granulating, and making a blended masterbatch; The copper-clad aluminum power cable is prepared by the following steps: passing the copper-clad aluminum wire into a wire drawing machine, drawing the wire, annealing, and twisting the wire to obtain a copper-clad aluminum wire core, wrapping a mica tape around the outside of the copper-clad aluminum wire core to form a shielding layer, and then extruding a blended masterbatch as a raw material outside the shielding layer to form an outer sheath layer, steam cross-linking, cooling in a water tank, and air drying in a drying machine to obtain a copper-clad aluminum power cable; The modified filler is prepared by the following steps: Step A1: boron nitride and sodium hydroxide solution are mixed, and the mixture is reacted for 16-18 hours at a stirring rate of 200-300 rpm and a temperature of 120° C. to obtain activated boron nitride; the activated boron nitride, 3-glycidyloxypropyltrimethoxysilane and ethanol solution are mixed, ultrasonically dispersed for 20-30 minutes, and the mixture is reacted for 6-8 hours at a stirring rate of 120-150 rpm and a temperature of 60° C.; propargylamine is then added, and the reaction is continued for 24 hours to obtain modified boron nitride; Step A2: Modified boron nitride, composite silicon microspheres, copper sulfate and N,N-dimethylformamide are mixed, ultrasonically dispersed for 5-10 minutes, stirred and added with pentamethyldiethylenetriamine under nitrogen protection at a stirring rate of 120-150 rpm and a temperature of 30°C, reacted for 24 hours, then heated to 50°C and added with iodoethane, and continued to react for 24 hours to obtain composite boron nitride; Step A3: Mix the composite boron nitride and ethanol, stir at a stirring rate of 150-200 rpm and a temperature of 5° C., add dimethyl phosphate, heat to room temperature, and react for 4-6 hours to obtain a modified filler.

2. A copper-clad aluminum power cable according to claim 1, characterized in that: In step A1, the molar concentration of the sodium hydroxide solution is 5 mol / L, the amount ratio of boron nitride to the sodium hydroxide solution is 2-3 g: 60-80 mL, the volume fraction of the ethanol solution is 80%, and the amount ratio of activated boron nitride, 3-glycidyloxypropyltrimethoxysilane, ethanol solution and propargylamine is 2-2.5 g: 0.008-0.01 mol: 60-70 mL: 0.008-0.01 mol.

3. The copper-clad aluminum power cable according to claim 1, characterized in that: In step A2, the amount ratio of modified boron nitride, composite silicon microspheres, copper sulfate, pentamethyldiethylenetriamine and iodine ethane is 2-2.5 g: 1.2-1.5 g: 12-14 g: 10-12 mL: 0.008-0.01 mol.

4. The copper-clad aluminum power cable according to claim 1, characterized in that: In step A3, the ratio of composite boron nitride, ethanol and dimethyl phosphate is: 3-3.5 g: 60-80 mL: 0.4-0.5 g.

5. The copper-clad aluminum power cable according to claim 1, characterized in that: The composite silicon microspheres are prepared by the following steps: Step B1: dimethyldimethoxysilane, phenyltrimethoxysilane and deionized water are mixed, stirred at a stirring rate of 150-200 rpm, and ammonia water is added at room temperature, and the mixture is reacted for 2-3 hours, and then 3-aminopropyltrimethoxysilane is added, and the reaction is continued for 1-1.5 hours, and then spray-dried to obtain aminosilicon microspheres; Step B2: p-bromomethylbenzoic acid, sodium azide and N,N-dimethylformamide are mixed, and the mixture is reacted for 12-14 hours at a stirring rate of 100-150 rpm and a temperature of 50°C to obtain intermediate a. Intermediate a, aminosilicon microspheres and N,N-dimethylformamide are mixed, and the mixture is stirred at a stirring rate of 60-80 rpm and room temperature, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added, and the mixture is reacted for 24 hours to obtain modified silicon microspheres. Step B3: The modified silicon microspheres and the ethylene glycol solution are mixed, ultrasonically dispersed for 10-15 minutes, stirred at a stirring rate of 100-120 rpm and a temperature of 130° C., and chloroplatinic acid solution is added, and the reaction is carried out for 3-4 hours to obtain composite silicon microspheres.

6. The copper-clad aluminum power cable according to claim 5, characterized in that: In step B1: the mass fraction of ammonia water is 25%, and the usage ratio of dimethyldimethoxysilane, phenyltrimethoxysilane, deionized water, ammonia water and 3-aminopropyltrimethoxysilane is 0.04-0.05 mol: 0.045-0.055 mol: 280-300 mL: 20-24 mL: 0.01-0.012 mol.

7. The copper-clad aluminum power cable according to claim 5, characterized in that: In step B2: the ratio of p-bromomethylbenzoic acid to sodium azide is 0.01-0.011 mol: 0.014-0.015 mol, and the ratio of intermediate a, aminosilicon microspheres, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide is 0.01-0.011 mol: 2-3 g: 0.02-0.021 mol: 0.02-0.023 mol.

8. The copper-clad aluminum power cable according to claim 5, characterized in that: In step B3: the volume fraction of ethylene glycol solution is 60%, the mass fraction of chloroplatinic acid solution is 16%, and the dosage ratio of modified silicon microspheres, ethanol solution and chloroplatinic acid solution is 1.2-1.5g:100-110mL:1-1.2mL.

Images