A high temperature and high pressure resistant electric power pipe and its preparation method

Abstract

The invention discloses a high-temperature and high-voltage resistant electric power pipe and a preparation method thereof. The electric power pipe comprises the following raw materials in parts by weight: 100-120 parts of polyethylene masterbatch, 5-10 parts of a modifier, 0.5-1 parts of benzoyl peroxide and 20-30 parts of a modified filler. During the melt extrusion of the raw materials, the maleimide structure on the side chain of the modifier molecule can be grafted with the polyethylene molecule chain, thereby increasing the cross-linking site, resulting in improved high-temperature and high-voltage resistance effects of the material. At the same time, organic silicon segments and benzene ring structures are added to the polymer molecules, thereby improving the high-temperature resistance effect of the material. After reflux treatment in water, the siloxane structure in the modified filler and the siloxane structure in the modifier molecule can be hydrolyzed and condensed, so that a three-dimensional grid structure is formed between the polymer molecular chains. The modified filler forms a core-shell structure with cage-type silsesquioxane as the core and boron nitride as the shell, and the three-dimensional grid structure of the polymer itself can greatly improve its own high-temperature and high-voltage resistance effects.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power pipe preparation, and in particular to a high-temperature and high-pressure resistant electric power pipe and a preparation method thereof. Background Art

[0002] With the continuous advancement of industrial and urbanization, the continuous upgrading of power systems and the expansion of power grids, the requirements for power transmission equipment have also increased. Especially in high temperature and high voltage environments, traditional power pipes have insufficient temperature and pressure resistance, resulting in limited reliability and service life. The main insulating material used in high-voltage and ultra-high-voltage plastic cables is cross-linked polyethylene. Cross-linked polyethylene has the advantages of being cheap and easy to obtain, high electrical insulation strength, low dielectric constant and dielectric loss, high volume resistivity, and low density. However, cross-linked polyethylene also has problems such as space charge accumulation. With the increase of the load of long-distance transmission cables, the increase of transmission voltage levels, and the increase of operating temperatures, power cable insulation materials require higher voltage breakdown resistance levels and high temperature resistance to ensure normal operation. Summary of the invention

[0003] The purpose of the present invention is to provide a high temperature and high pressure resistant electric power pipe and a preparation method thereof, so as to solve the problem that the high temperature and high pressure resistance of electric power pipes at the current stage is generally poor.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A method for preparing a high temperature and high pressure resistant electric power pipe comprises the following steps:

[0006] Step A1: 1,3-bis(aminopropyl)tetramethyldisiloxane, maleic anhydride and toluene are mixed, stirred for 1-1.5 hours at a speed of 200-300 r / min and a temperature of 20-25° C., zinc chloride and bis(trimethylsilylmethyl)amine are added, the temperature is raised to 80-85° C., and the reaction is carried out for 3-5 hours to obtain a capping agent, tetramethylcyclotetrasiloxane, allyl glycidyl ether, chloroplatinic acid and tetrahydrofuran are mixed uniformly, and the reaction is carried out for 3-5 hours at a speed of 120-150 r / min and a temperature of 60-70° C. to obtain a modified monomer;

[0007] Step A2: octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, modified monomer, tetramethylammonium hydroxide, end-capping agent and dimethyl sulfoxide are mixed uniformly, nitrogen is introduced for protection, and the reaction is carried out for 3-5 hours at a speed of 120-150 r / min and a temperature of 105-110° C. to obtain functionalized polysiloxane; functionalized polysiloxane, KH550 and toluene are mixed uniformly, nitrogen is introduced for protection, and the reaction is carried out for 1-1.5 hours at a speed of 200-300 r / min, a temperature of 20-25° C. and a pH value of 10-11 to obtain a modifier;

[0008] Step A3: Weigh the following raw materials in parts by weight: 100-120 parts of polyethylene masterbatch, 5-10 parts of modifier, 0.5-1 part of benzoyl peroxide and 20-30 parts of modified filler, add the raw materials into a twin-screw extruder, melt-extrude at a temperature of 130-140°C to obtain a pretreated masterbatch, add the pretreated masterbatch into water, reflux at a temperature of 100-105°C for 20-30 minutes, melt-extrude again, cool and shape, and obtain a high temperature and high pressure resistant power pipe.

[0009] Furthermore, the amount ratio of 1,3-bis(aminopropyl)tetramethyldisiloxane, maleic anhydride, zinc chloride and bis(trimethylsilylmethyl)amine described in step A1 is 1 mol:2 mol:1 g:1.5 g, the molar ratio of tetramethylcyclotetrasiloxane and allyl glycidyl ether is 1:4, and the amount of chloroplatinic acid used is 1‰ of the mass of allyl glycidyl ether.

[0010] Furthermore, the molar ratio of octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, modified monomer, tetramethylammonium hydroxide and capping agent described in step A2 is 1:1:0.4:3:2, and the molar ratio of epoxy group on the functionalized polysiloxane and KH550 is 1:1.

[0011] Further, the modified filler is prepared by the following steps:

[0012] Step B1: mixing hexagonal boron nitride and sodium hydroxide solution, stirring for 10-15 hours at a speed of 200-300 r / min and a temperature of 120-125° C., filtering to remove the filtrate, washing the substrate with deionized water until neutral, to obtain hydroxylated hexagonal boron nitride, dispersing the hydroxylated hexagonal boron nitride in ethanol, stirring at a speed of 120-150 r / min and a temperature of 60-70° C., adding KH570 and deionized water, and reacting for 20-30 minutes to obtain modified boron nitride;

[0013] Step B2: Ethyltrimethoxysilane, isopropanol, deionized water and sodium hydroxide are mixed uniformly, reacted for 3-5 hours at a speed of 120-150 r / min and a temperature of 85-90° C., cooled to 20-25° C., and reacted for 10-15 hours to obtain octaethylcyclotetrasiloxane sodium tetrasiloxide. Octaethylcyclotetrasiloxane sodium tetrasiloxide, triethylamine and tetrahydrofuran are mixed uniformly, nitrogen is introduced for protection, stirred and methyldichlorosilane is added at a speed of 200-300 r / min and a temperature of 0-3° C., reacted for 3-5 hours, heated to 20-25° C., and reacted for 18-22 hours to obtain dihydrogen cage-type silsesquioxane;

[0014] Step B3: The modified boron nitride, dihydrogen cage silsesquioxane, chloroplatinic acid and toluene are mixed evenly, nitrogen is introduced for protection, and the reaction is carried out for 10-15 hours at a speed of 200-300 r / min and a temperature of 80-85°C to obtain a precursor. The precursor, 3-mercaptopropyltrimethoxysilane, benzophenone and toluene are mixed evenly, nitrogen is introduced for protection, and the reaction is carried out for 5-10 minutes at a speed of 150-200 r / min and 365nm ultraviolet light irradiation to obtain a modified filler.

[0015] Furthermore, the dosage ratio of the hexagonal boron nitride and the sodium hydroxide solution in step B1 is 1 g:10 mL, the mass fraction of the sodium hydroxide solution is 20%, and the dosage of KH570 is 3% of the mass of the hydroxylated hexagonal boron nitride.

[0016] Furthermore, the amount ratio of ethyltrimethoxysilane, isopropanol, deionized water and sodium hydroxide described in step B2 is 6mmol:6mL:7mmol:4mmol, and the amount ratio of sodium octaethylcyclotetrasiloxane tetrasiliconate, triethylamine, tetrahydrofuran and methyldichlorosilane is 10g:4mL:30mL:3.5g.

[0017] Furthermore, the mass ratio of the modified boron nitride and dihydrogen cage silsesquioxane described in step B3 is 5:1, the amount of chloroplatinic acid used is 1‰ of the mass of dihydrogen cage silsesquioxane, the molar ratio of the double bond on the precursor and 3-mercaptopropyltrimethoxysilane is 1:1, and the amount of benzophenone used is 1% of 3-mercaptopropyltrimethoxysilane.

[0018] Beneficial effects of the invention: A high-temperature and high-voltage resistant electric power pipe disclosed in the invention comprises the following raw materials: polyethylene masterbatch, a modifier, benzoyl peroxide and a modified filler, the modifier is prepared by using 1,3-bis(aminopropyl)tetramethyldisiloxane and maleic anhydride as raw materials, so that the maleic anhydride is ring-opened and dehydrated with the amino group on the 1,3-bis(aminopropyl)tetramethyldisiloxane to form a maleimide structure, thereby obtaining a capping agent, tetramethylcyclotetrasiloxane is reacted with allyl glycidyl ether, so that the Si-H bond on the tetramethylcyclotetrasiloxane reacts with the double bond on the allyl glycidyl ether to obtain a modified monomer, octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane and the modified monomer are ring-opened, and then polymerized with the capping agent to obtain a functionalized polysiloxane, and the functionalized polysiloxane is reacted with KH550, so that the epoxy group on the functionalized polysiloxane reacts with the amino group on KH550 to obtain a modifier.

[0019] The modified filler is prepared by treating hexagonal boron nitride as a raw material with a sodium hydroxide solution to obtain hydroxylated hexagonal boron nitride, treating the hydroxylated hexagonal boron nitride with KH570 to graft double bonds on the surface to obtain modified boron nitride, hydrolyzing and condensing ethyltrimethoxysilane to obtain sodium octaethylcyclotetrasiloxane tetrasilanolate, reacting sodium octaethylcyclotetrasiloxane tetrasilanolate with methyldichlorosilane to react the sodium silanolate on the sodium octaethylcyclotetrasiloxane tetrasilanolate with the chlorine atom site on the methyldichlorosilane to obtain dihydrogen cage-type silsesquioxane, reacting the modified boron nitride with dihydrogen cage-type silsesquioxane to react part of the double bonds on the modified boron nitride with the Si-H bonds on the dihydrogen cage-type silsesquioxane to obtain a precursor, reacting the precursor with 3-mercaptopropyltrimethoxysilane to react the remaining double bonds of the precursor with 3-mercaptopropyltrimethoxysilane to obtain the modified filler.

[0020] During the melt extrusion of the raw materials, the maleimide structure on the side chain of the modifier molecule can be grafted with the polyethylene molecular chain, thereby increasing the cross-linking sites, resulting in improved high temperature and high pressure resistance of the material. At the same time, silicone segments and benzene ring structures are added to the polymer molecules, further improving the high temperature resistance of the material. After the pretreated masterbatch is refluxed in water, the siloxane structure in the modified filler and the siloxane structure in the modifier molecule can be hydrolyzed and condensed, so that a three-dimensional grid structure is formed between the polymer molecular chains. The modified filler forms a core-shell structure with cage-type silsesquioxane as the core and boron nitride as the shell, which can greatly improve its own high temperature and high pressure resistance together with the three-dimensional grid structure of the polymer itself. DETAILED DESCRIPTION

[0021] 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.

[0022] Embodiment 1: A method for preparing a high temperature and high pressure resistant electric power pipe, comprising the following steps:

[0023] Step A1: 1,3-bis(aminopropyl)tetramethyldisiloxane, maleic anhydride and toluene are mixed, stirred for 1 hour at a speed of 200 r / min and a temperature of 20°C, zinc chloride and bis(trimethylsilylmethyl)amine are added, the temperature is raised to 80°C, and the reaction is carried out for 3 hours to obtain a capping agent, tetramethylcyclotetrasiloxane, allyl glycidyl ether, chloroplatinic acid and tetrahydrofuran are mixed uniformly, and the reaction is carried out for 3 hours at a speed of 120 r / min and a temperature of 60°C to obtain a modified monomer;

[0024] Step A2: octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, modified monomer, tetramethylammonium hydroxide, end-capping agent and dimethyl sulfoxide are mixed uniformly, nitrogen is introduced for protection, and the reaction is carried out for 3 hours at a speed of 120 r / min and a temperature of 105° C. to obtain functionalized polysiloxane; functionalized polysiloxane, KH550 and toluene are mixed uniformly, nitrogen is introduced for protection, and the reaction is carried out for 1 hour at a speed of 200 r / min, a temperature of 20° C. and a pH value of 10 to obtain a modifier;

[0025] Step A3: Weigh the following raw materials in parts by weight: 100 parts of polyethylene masterbatch, 5 parts of modifier, 0.5 parts of benzoyl peroxide and 20 parts of modified filler, add the raw materials into a twin-screw extruder, melt-extrude at a temperature of 130°C to obtain a pretreated masterbatch, add the pretreated masterbatch into water, reflux at a temperature of 100°C for 20 minutes, melt-extrude again, cool and shape, and obtain a high temperature and high pressure resistant power pipe.

[0026] The amount ratio of 1,3-bis(aminopropyl)tetramethyldisiloxane, maleic anhydride, zinc chloride and bis(trimethylsilylmethyl)amine described in step A1 is 1 mol:2 mol:1 g:1.5 g, the molar ratio of tetramethylcyclotetrasiloxane and allyl glycidyl ether is 1:4, and the amount of chloroplatinic acid used is 1‰ of the mass of allyl glycidyl ether.

[0027] The molar ratio of octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, modified monomer, tetramethylammonium hydroxide and capping agent described in step A2 is 1:1:0.4:3:2, and the molar ratio of epoxy group on the functionalized polysiloxane and KH550 is 1:1.

[0028] The average molecular weight of the polyethylene masterbatch described in step A3 is 1.6 million and the density is 0.95 g / cm 3 .

[0029] The modified filler is prepared by the following steps:

[0030] Step B1: Hexagonal boron nitride and sodium hydroxide solution are mixed, stirred at a speed of 200 r / min and a temperature of 120° C. for 10 hours, and the filtrate is removed by filtering, and the substrate is washed with deionized water until it is neutral to obtain hydroxylated hexagonal boron nitride. The hydroxylated hexagonal boron nitride is dispersed in ethanol, stirred at a speed of 120 r / min and a temperature of 60° C., and KH570 and deionized water are added to react for 20 minutes to obtain modified boron nitride;

[0031] Step B2: Ethyltrimethoxysilane, isopropanol, deionized water and sodium hydroxide are mixed evenly, reacted at a speed of 120 r / min and a temperature of 85° C. for 3 hours, then cooled to 20° C. and continued to react for 10 hours to obtain octaethylcyclotetrasiloxane sodium tetrasiloxide, octaethylcyclotetrasiloxane sodium tetrasiloxide, triethylamine and tetrahydrofuran are mixed evenly, nitrogen is introduced for protection, stirred at a speed of 200 r / min and a temperature of 0° C., methyldichlorosilane is added, the reaction is carried out for 3 hours, the temperature is raised to 20° C., and the reaction is carried out for 18 hours to obtain dihydrogen cage-type silsesquioxane;

[0032] Step B3: The modified boron nitride, dihydrogen cage silsesquioxane, chloroplatinic acid and toluene are mixed evenly, nitrogen is introduced for protection, and the reaction is carried out for 10 hours at a speed of 200 r / min and a temperature of 80°C to obtain a precursor. The precursor, 3-mercaptopropyltrimethoxysilane, benzophenone and toluene are mixed evenly, nitrogen is introduced for protection, and the reaction is carried out for 5 minutes at a speed of 150 r / min and 365 nm ultraviolet light irradiation to obtain a modified filler.

[0033] The dosage ratio of hexagonal boron nitride and sodium hydroxide solution in step B1 is 1 g:10 mL, the mass fraction of the sodium hydroxide solution is 20%, and the dosage of KH570 is 3% of the mass of hydroxylated hexagonal boron nitride.

[0034] The amount ratio of ethyltrimethoxysilane, isopropanol, deionized water and sodium hydroxide described in step B2 is 6mmol:6mL:7mmol:4mmol, and the amount ratio of sodium octaethylcyclotetrasiloxane tetrasiliconate, triethylamine, tetrahydrofuran and methyldichlorosilane is 10g:4mL:30mL:3.5g.

[0035] The mass ratio of the modified boron nitride and dihydrogen cage silsesquioxane described in step B3 is 5:1, the amount of chloroplatinic acid used is 1‰ of the mass of dihydrogen cage silsesquioxane, the molar ratio of the double bond on the precursor and 3-mercaptopropyltrimethoxysilane is 1:1, and the amount of benzophenone used is 1% of 3-mercaptopropyltrimethoxysilane.

[0036] Embodiment 2: A method for preparing a high temperature and high pressure resistant electric power pipe, comprising the following steps:

[0037] Step A1: 1,3-bis(aminopropyl)tetramethyldisiloxane, maleic anhydride and toluene are mixed, stirred for 1 hour at a speed of 200 r / min and a temperature of 25°C, zinc chloride and bis(trimethylsilylmethyl)amine are added, the temperature is raised to 85°C, and the reaction is carried out for 4 hours to obtain a capping agent, tetramethylcyclotetrasiloxane, allyl glycidyl ether, chloroplatinic acid and tetrahydrofuran are mixed uniformly, and the reaction is carried out for 4 hours at a speed of 120 r / min and a temperature of 65°C to obtain a modified monomer;

[0038] Step A2: octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, modified monomer, tetramethylammonium hydroxide, end-capping agent and dimethyl sulfoxide were mixed uniformly, nitrogen was introduced for protection, and the reaction was carried out for 4 hours at a speed of 120 r / min and a temperature of 110° C. to obtain functionalized polysiloxane; functionalized polysiloxane, KH550 and toluene were mixed uniformly, nitrogen was introduced for protection, and the reaction was carried out for 1.5 hours at a speed of 200 r / min, a temperature of 20° C. and a pH value of 11 to obtain a modifier;

[0039] Step A3: Weigh the following raw materials in parts by weight: 110 parts of polyethylene masterbatch, 8 parts of modifier, 0.8 parts of benzoyl peroxide and 25 parts of modified filler, add the raw materials into a twin-screw extruder, melt-extrude at a temperature of 135°C to obtain a pretreated masterbatch, add the pretreated masterbatch into water, reflux at a temperature of 105°C for 25 minutes, melt-extrude again, cool and shape, and obtain a high temperature and high pressure resistant power pipe.

[0040] The amount ratio of 1,3-bis(aminopropyl)tetramethyldisiloxane, maleic anhydride, zinc chloride and bis(trimethylsilylmethyl)amine described in step A1 is 1 mol:2 mol:1 g:1.5 g, the molar ratio of tetramethylcyclotetrasiloxane and allyl glycidyl ether is 1:4, and the amount of chloroplatinic acid used is 1‰ of the mass of allyl glycidyl ether.

[0041] The molar ratio of octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, modified monomer, tetramethylammonium hydroxide and capping agent described in step A2 is 1:1:0.4:3:2, and the molar ratio of epoxy group on the functionalized polysiloxane and KH550 is 1:1.

[0042] The average molecular weight of the polyethylene masterbatch described in step A3 is 1.6 million and the density is 0.95 g / cm 3 .

[0043] The modified filler is prepared by the following steps:

[0044] Step B1: Hexagonal boron nitride and sodium hydroxide solution are mixed, stirred at a speed of 200 r / min and a temperature of 125°C for 10 hours, and the filtrate is removed by filtering, and the substrate is washed with deionized water until it is neutral to obtain hydroxylated hexagonal boron nitride. The hydroxylated hexagonal boron nitride is dispersed in ethanol, stirred at a speed of 120 r / min and a temperature of 65°C, and KH570 and deionized water are added to react for 25 minutes to obtain modified boron nitride;

[0045] Step B2: Ethyltrimethoxysilane, isopropanol, deionized water and sodium hydroxide are mixed evenly, reacted at a speed of 150 r / min and a temperature of 85° C. for 4 hours, then cooled to 25° C. and reacted for 10 hours to obtain sodium octaethylcyclotetrasiloxane tetrasiloxide. Sodium octaethylcyclotetrasiloxane tetrasiloxide, triethylamine and tetrahydrofuran are mixed evenly, nitrogen is introduced for protection, stirred at a speed of 300 r / min and a temperature of 3° C., methyldichlorosilane is added, the reaction is carried out for 4 hours, the temperature is raised to 20° C., and the reaction is carried out for 20 hours to obtain dihydrogen cage-type silsesquioxane;

[0046] Step B3: The modified boron nitride, dihydrogen cage silsesquioxane, chloroplatinic acid and toluene are mixed evenly, nitrogen is introduced for protection, and the reaction is carried out for 13 hours at a speed of 300 r / min and a temperature of 80°C to obtain a precursor. The precursor, 3-mercaptopropyltrimethoxysilane, benzophenone and toluene are mixed evenly, nitrogen is introduced for protection, and the reaction is carried out for 8 minutes at a speed of 150 r / min and 365 nm ultraviolet light irradiation to obtain a modified filler.

[0047] The dosage ratio of hexagonal boron nitride and sodium hydroxide solution in step B1 is 1 g:10 mL, the mass fraction of the sodium hydroxide solution is 20%, and the dosage of KH570 is 3% of the mass of hydroxylated hexagonal boron nitride.

[0048] The amount ratio of ethyltrimethoxysilane, isopropanol, deionized water and sodium hydroxide described in step B2 is 6mmol:6mL:7mmol:4mmol, and the amount ratio of sodium octaethylcyclotetrasiloxane tetrasiliconate, triethylamine, tetrahydrofuran and methyldichlorosilane is 10g:4mL:30mL:3.5g.

[0049] The mass ratio of the modified boron nitride and dihydrogen cage silsesquioxane described in step B3 is 5:1, the amount of chloroplatinic acid used is 1‰ of the mass of dihydrogen cage silsesquioxane, the molar ratio of the double bond on the precursor and 3-mercaptopropyltrimethoxysilane is 1:1, and the amount of benzophenone used is 1% of 3-mercaptopropyltrimethoxysilane.

[0050] Embodiment 3: A method for preparing a high temperature and high pressure resistant electric power pipe, comprising the following steps:

[0051] Step A1: 1,3-bis(aminopropyl)tetramethyldisiloxane, maleic anhydride and toluene are mixed, stirred for 1.5 hours at a speed of 300 r / min and a temperature of 25°C, zinc chloride and bis(trimethylsilylmethyl)amine are added, the temperature is raised to 85°C, and the reaction is carried out for 5 hours to obtain a capping agent, tetramethylcyclotetrasiloxane, allyl glycidyl ether, chloroplatinic acid and tetrahydrofuran are mixed uniformly, and the reaction is carried out for 5 hours at a speed of 150 r / min and a temperature of 70°C to obtain a modified monomer;

[0052] Step A2: octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, modified monomer, tetramethylammonium hydroxide, end-capping agent and dimethyl sulfoxide were mixed uniformly, nitrogen was introduced for protection, and the reaction was carried out for 5 hours at a speed of 150 r / min and a temperature of 110° C. to obtain functionalized polysiloxane; functionalized polysiloxane, KH550 and toluene were mixed uniformly, nitrogen was introduced for protection, and the reaction was carried out for 1.5 hours at a speed of 300 r / min, a temperature of 25° C. and a pH value of 11 to obtain a modifier;

[0053] Step A3: Weigh the following raw materials in parts by weight: 120 parts of polyethylene masterbatch, 10 parts of modifier, 1 part of benzoyl peroxide and 30 parts of modified filler, add the raw materials into a twin-screw extruder, melt-extrude at a temperature of 140°C to obtain a pretreated masterbatch, add the pretreated masterbatch into water, reflux at a temperature of 105°C for 30 minutes, melt-extrude again, cool and shape, and obtain a high temperature and high pressure resistant power pipe.

[0054] The amount ratio of 1,3-bis(aminopropyl)tetramethyldisiloxane, maleic anhydride, zinc chloride and bis(trimethylsilylmethyl)amine described in step A1 is 1 mol:2 mol:1 g:1.5 g, the molar ratio of tetramethylcyclotetrasiloxane and allyl glycidyl ether is 1:4, and the amount of chloroplatinic acid used is 1‰ of the mass of allyl glycidyl ether.

[0055] The molar ratio of octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, modified monomer, tetramethylammonium hydroxide and capping agent described in step A2 is 1:1:0.4:3:2, and the molar ratio of epoxy group on the functionalized polysiloxane and KH550 is 1:1.

[0056] The average molecular weight of the polyethylene masterbatch described in step A3 is 1.6 million and the density is 0.95 g / cm 3 .

[0057] The modified filler is prepared by the following steps:

[0058] Step B1: Hexagonal boron nitride and sodium hydroxide solution are mixed, stirred at a speed of 300 r / min and a temperature of 125°C for 15 hours, and the filtrate is removed by filtering, and the substrate is washed with deionized water until it is neutral to obtain hydroxylated hexagonal boron nitride. The hydroxylated hexagonal boron nitride is dispersed in ethanol, stirred at a speed of 150 r / min and a temperature of 70°C, and KH570 and deionized water are added to react for 30 minutes to obtain modified boron nitride;

[0059] Step B2: Ethyltrimethoxysilane, isopropanol, deionized water and sodium hydroxide were mixed evenly, reacted at a speed of 150 r / min and a temperature of 90° C. for 5 h, then cooled to 25° C. and continued to react for 15 h to obtain sodium octaethylcyclotetrasiloxane tetrasiloxide. Sodium octaethylcyclotetrasiloxane tetrasiloxide, triethylamine and tetrahydrofuran were mixed evenly, nitrogen was introduced for protection, stirred at a speed of 300 r / min and a temperature of 3° C., methyldichlorosilane was added, the mixture was reacted for 5 h, the mixture was heated to 25° C. and reacted for 22 h to obtain dihydrogen cage-type silsesquioxane;

[0060] Step B3: The modified boron nitride, dihydrogen cage silsesquioxane, chloroplatinic acid and toluene are mixed evenly, nitrogen is introduced for protection, and the reaction is carried out for 15 hours at a speed of 300 r / min and a temperature of 85°C to obtain a precursor. The precursor, 3-mercaptopropyltrimethoxysilane, benzophenone and toluene are mixed evenly, nitrogen is introduced for protection, and the reaction is carried out for 10 minutes at a speed of 200 r / min and 365 nm ultraviolet light irradiation to obtain a modified filler.

[0061] The dosage ratio of hexagonal boron nitride and sodium hydroxide solution in step B1 is 1 g:10 mL, the mass fraction of the sodium hydroxide solution is 20%, and the dosage of KH570 is 3% of the mass of hydroxylated hexagonal boron nitride.

[0062] The amount ratio of ethyltrimethoxysilane, isopropanol, deionized water and sodium hydroxide described in step B2 is 6mmol:6mL:7mmol:4mmol, and the amount ratio of sodium octaethylcyclotetrasiloxane tetrasiliconate, triethylamine, tetrahydrofuran and methyldichlorosilane is 10g:4mL:30mL:3.5g.

[0063] The mass ratio of the modified boron nitride and dihydrogen cage silsesquioxane described in step B3 is 5:1, the amount of chloroplatinic acid used is 1‰ of the mass of dihydrogen cage silsesquioxane, the molar ratio of the double bond on the precursor and 3-mercaptopropyltrimethoxysilane is 1:1, and the amount of benzophenone used is 1% of 3-mercaptopropyltrimethoxysilane.

[0064] Comparative Example 1: Compared with Example 1, no modified monomer was added to this comparative example, and the remaining steps were the same.

[0065] Comparative Example 2: Compared with Example 1, this comparative example uses modified hexagonal boron nitride instead of the precursor, and the remaining steps are the same.

[0066] Comparative Example 3. Compared with Example 1, KH570, dihydrogen cage silsesquioxane, chloroplatinic acid and toluene are uniformly mixed, nitrogen is introduced for protection, and the reaction is carried out for 10 hours at a speed of 200 r / min and a temperature of 80°C. The obtained product replaces the modified filler, and the other steps are the same.

[0067] The materials obtained in Examples 1-3 and Comparative Examples 1-3 were made into squares with a thickness of 5 mm and a length of 10 mm according to the standard of GB / T1633-2000, with a load of 4 kg and a heating rate of 50°C / h. The Vicat softening point was tested. According to the standard of GB / T1408.1-2016, the sample thickness was 100 μm, the voltage rise rate was 0.5 kV / s, and the AC breakdown field strength was tested. The test results are shown in Table 1 below.

[0068]

[0069] It can be seen from Table 1 above that the present application has good high temperature and high voltage resistance effects.

[0070] 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 method for preparing a high temperature and high pressure resistant electric power pipe, characterized in that: The specific steps include: Step A1: 1,3-bis(aminopropyl)tetramethyldisiloxane, maleic anhydride and toluene are mixed and stirred, zinc chloride and bis(trimethylsilylmethyl)amine are added, and the temperature is raised to react to obtain a capping agent, and tetramethylcyclotetrasiloxane, allyl glycidyl ether, chloroplatinic acid and tetrahydrofuran are mixed and reacted to obtain a modified monomer; Step A2: octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, a modified monomer, tetramethylammonium hydroxide, a capping agent and dimethyl sulfoxide are uniformly mixed, nitrogen is introduced for protection, and a reaction is carried out to obtain a functionalized polysiloxane; the functionalized polysiloxane, KH550 and toluene are uniformly mixed, nitrogen is introduced for protection, and a reaction is carried out to obtain a modifier; Step A3: Weigh the following raw materials in parts by weight: 100-120 parts of polyethylene masterbatch, 5-10 parts of modifier, 0.5-1 part of benzoyl peroxide and 20-30 parts of modified filler, add the raw materials into a twin-screw extruder, melt-extrude at a temperature of 130-140° C. to obtain a pretreated masterbatch, add the pretreated masterbatch into water, reflux it, melt-extrude it again, cool it and shape it, and obtain a high temperature and high pressure resistant power pipe; The modified filler is prepared by the following steps: Step B1: After mixing and stirring hexagonal boron nitride and sodium hydroxide solution, the filtrate is removed by filtering, and the substrate is washed with deionized water until it is neutral to obtain hydroxylated hexagonal boron nitride. The hydroxylated hexagonal boron nitride is dispersed in ethanol, stirred, and KH570 and deionized water are added to react to obtain modified boron nitride; Step B2: Ethyltrimethoxysilane, isopropanol, deionized water and sodium hydroxide are mixed for reaction to obtain sodium octaethylcyclotetrasiloxane tetrasilanolate, sodium octaethylcyclotetrasiloxane tetrasilanolate, triethylamine and tetrahydrofuran are mixed evenly, nitrogen is introduced for protection, methyldichlorosilane is added for stirring, and a reaction is carried out to obtain dihydrogen cage-type silsesquioxane; Step B3: Modified boron nitride, dihydrogen cage silsesquioxane, chloroplatinic acid and toluene are mixed and reacted to obtain a precursor, the precursor, 3-mercaptopropyltrimethoxysilane, benzophenone and toluene are evenly mixed, nitrogen is introduced for protection, and a reaction is carried out to obtain a modified filler.

2. The method for preparing a high temperature and high pressure resistant electric power pipe according to claim 1, characterized in that: The amount ratio of 1,3-bis(aminopropyl)tetramethyldisiloxane, maleic anhydride, zinc chloride and bis(trimethylsilylmethyl)amine described in step A1 is 1 mol:2 mol:1 g:1.5 g, and the molar ratio of tetramethylcyclotetrasiloxane and allyl glycidyl ether is 1:

4.

3. The method for preparing a high temperature and high pressure resistant electric power pipe according to claim 1, characterized in that: The molar ratio of octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, modified monomer, tetramethylammonium hydroxide and capping agent described in step A2 is 1:1:0.4:3:2, and the molar ratio of epoxy group on the functionalized polysiloxane and KH550 is 1:

1.

4. The method for preparing a high temperature and high pressure resistant electric power pipe according to claim 1, characterized in that: The dosage ratio of hexagonal boron nitride and sodium hydroxide solution in step B1 is 1 g:10 mL, and the dosage of KH570 is 3% of the mass of hydroxylated hexagonal boron nitride.

5. The method for preparing a high temperature and high pressure resistant electric power pipe according to claim 1, characterized in that: The amount ratio of ethyltrimethoxysilane, isopropanol, deionized water and sodium hydroxide described in step B2 is 6mmol:6mL:7mmol:4mmol, and the amount ratio of sodium octaethylcyclotetrasiloxane tetrasiliconate, triethylamine, tetrahydrofuran and methyldichlorosilane is 10g:4mL:30mL:3.5g.

6. The method for preparing a high temperature and high pressure resistant electric power pipe according to claim 1, characterized in that: The mass ratio of the modified boron nitride and dihydrogen cage-type silsesquioxane described in step B3 is 5:1, and the molar ratio of the double bond on the precursor and 3-mercaptopropyltrimethoxysilane is 1:

1.

7. A high temperature and high pressure resistant electric power pipe, characterized in that: Prepared according to any one of claims 1 to 6.

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