Fire-resistant insulating inorganic fiber sleeve

Abstract

The invention relates to a fire-resistant insulating inorganic fiber sleeve, and belongs to the technical field of glass fiber sleeves, and the fire-resistant insulating inorganic fiber sleeve comprises the following steps: dip-coating a layer of fluorinated modified graphene oxide on the surface of a pretreated fiber sleeve to form an insulating coating; coating a layer of silicon polymer on the surface of the insulating coating to form a middle layer; coating a layer of flame-retardant reinforcing material on the surface of the middle layer to form a fire-resistant coating, so as to form a fire-resistant insulating inorganic fiber sleeve consisting of the pretreated fiber sleeve, the insulating coating, the middle layer and the fire-resistant coating; according to the technical scheme, the phosphorus-containing compound is combined with the hydroxyethyl methylacrylate to obtain the flame-retardant compound; the flame-retardant compound is combined with vinyl-containing silsesquioxane, and a flame-retardant reinforced material is obtained; the fluorinated modified graphene oxide is prepared by grafting and modifying the graphene oxide through the fluorine-containing compound, so that the fire resistance, the insulating property, the thermal stability and the mechanical property of the inorganic fiber sleeve are improved on the whole, and the comprehensive performance of the inorganic fiber sleeve is relatively good.

Description

Technical Field

[0001] The invention belongs to the technical field of glass fiber sleeves, and in particular relates to a fire-resistant and insulating inorganic fiber sleeve. Background Art

[0002] Fiber sleeves are made of glass fiber reinforced braids. In wires and other important electronic components, they are mainly placed on the outside of the components to protect the internal components and prevent important components from being damaged. Fiber sleeves have good electrical insulation, corrosion resistance, aging resistance, and heat dissipation. They also have excellent softness and elasticity. They can remain soft and resistant to bending at low temperatures without reducing their electrical insulation. Therefore, fiber sleeves are widely used in various fields such as electrical insulation materials, thermal insulation materials, aerospace, and power equipment.

[0003] The existing fiber sleeves still have defects such as poor fire resistance and poor insulation performance during use under certain high pressure, high temperature or special environments. Due to their insufficient performance, there are safety hazards inside the line and certain damage to electronic components in normal operation, which seriously affects the safety and service life of the fiber sleeve. Currently, most people adopt the method of coating the surface of the fiber sleeve to make it have more excellent performance. Therefore, we need to prepare a fire-resistant and insulating inorganic fiber sleeve with good fire resistance, insulation, mechanical properties and thermal stability. Summary of the invention

[0004] The purpose of the present invention is to provide a fire-resistant and insulating inorganic fiber sleeve, wherein a flame-retardant composite is obtained by combining a phosphorus-containing compound with hydroxyethyl methacrylate; the phosphorus-containing compound not only has good flame-retardant properties, but also can be well combined with hydroxyethyl methacrylate, and can also provide reaction sites for subsequent reactions; the flame-retardant composite is combined with vinyl-containing silsesquioxane through free radical polymerization to obtain a flame-retardant reinforcement material; the flame-retardant composite is combined with vinyl-containing silsesquioxane, which not only has good bonding strength, but also can play a synergistic flame-retardant role, thereby improving the fire resistance, thermal stability and mechanical properties of the inorganic fiber sleeve; fluorinated modified graphene oxide is obtained by grafting graphene oxide with fluorine-containing compounds. Graphene; fluorine-containing compounds can improve the dispersibility of graphene oxide, increase its hydrophobicity and thermal stability, and graphene oxide has good insulating properties, which can improve the mechanical properties, thermal stability and insulating properties of inorganic fiber sleeves; a layer of fluorinated modified graphene oxide is dipped on the surface of the pretreated fiber sleeve to form an insulating coating; a layer of silicone polymer is coated on the surface of the insulating coating to form an intermediate layer; a layer of flame retardant reinforcing material is dipped on the surface of the intermediate layer to form a fire-resistant coating, thereby forming a fire-resistant and insulating inorganic fiber sleeve consisting of the pretreated fiber sleeve, the insulating coating, the intermediate layer and the fire-resistant coating; the prepared inorganic fiber sleeve has good fire resistance, insulation, thermal stability and mechanical properties, and has good comprehensive performance.

[0005] The technical problem to be solved by the present invention is as follows: the existing fiber sleeves still have defects such as poor fire resistance and poor insulation performance during use under certain high pressure, high temperature or special environments. Due to their insufficient performance, there are potential safety hazards inside the circuit, which may cause certain damage to electronic components in normal operation, seriously affecting the safety of use and service life of the fiber sleeves. Currently, most people adopt a method of coating the surface of the fiber sleeve to make it have more excellent performance. Therefore, we need to prepare a fire-resistant and insulating inorganic fiber sleeve with good fire resistance, insulation, mechanical properties and thermal stability.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A preparation process of a fire-resistant and insulating inorganic fiber sleeve comprises the following steps:

[0008] S1: dip-coating a layer of fluorinated modified graphene oxide on the surface of the pretreated fiber sleeve to form an insulating coating;

[0009] S2: coating a layer of silicone polymer on the surface of the insulating coating to form an intermediate layer;

[0010] S3: coating a layer of flame retardant reinforcing material on the surface of the middle layer to form a fire-resistant coating, thereby forming a fire-resistant and insulating inorganic fiber sleeve consisting of the pretreated fiber sleeve, the insulating coating, the middle layer and the fire-resistant coating;

[0011] The fluorinated modified graphene oxide is prepared by grafting modified graphene oxide with a fluorine-containing compound;

[0012] The preparation method of the flame retardant reinforced material comprises the following steps:

[0013] A1: combining phosphorus-containing compounds with hydroxyethyl methacrylate to obtain a flame retardant composite;

[0014] A2: The flame retardant composite is combined with vinyl-containing silsesquioxane by free radical polymerization to obtain a flame retardant reinforced material.

[0015] Furthermore, in step S1, the method for preparing the pretreated fiber sleeve comprises the following steps:

[0016] The fiber sleeve is placed in a sodium hydroxide solution, then heated to 90-100°C and maintained for 25-35 minutes, then washed with deionized water, and dried at 80-90°C for 20-30 minutes to obtain an alkalized fiber sleeve, the alkalized fiber sleeve and the ethanol / deionized water solution are mixed, and a silane coupling agent is added, refluxed at 115-125°C for 1-2 hours, and then dried at room temperature to obtain a pretreated fiber sleeve.

[0017] In the above reaction process, the fiber sleeve is treated with sodium hydroxide solution to expose the hydroxyl groups on the surface of the fiber sleeve. The surface of the fiber sleeve has hydroxyl groups. The silane coupling agent has silanol groups after hydrolysis, which can be combined with the hydroxyl groups on the surface of the fiber sleeve. The silane coupling agent is grafted to the surface of the fiber sleeve to finally obtain a pretreated fiber sleeve.

[0018] Furthermore, the mass ratio of the fiber sleeve to the sodium hydroxide solution is 1:20-30.

[0019] Furthermore, the mass ratio of the alkalized fiber sleeve to the ethanol / deionized water solution is 0.8-1.2:40-50.

[0020] Furthermore, the method for preparing the fiber sleeve comprises the following steps:

[0021] The basalt fiber is woven into a basalt fiber sleeve embryo, which is then passed through an embryo machine for rounding, and then passed through a high-temperature dewaxing furnace for dewaxing and shaping at 500-550°C for 40-60 minutes to obtain a fiber sleeve.

[0022] Furthermore, the silane coupling agent is composed of 3-(2-aminoethylamino)propylmethyldimethoxysilane and γ-glycidyloxypropyltrimethoxysilane mixed in a mass ratio of 0.7-0.8:0.3-0.4.

[0023] Further, in step S1, the method for preparing fluorinated modified graphene oxide comprises the following steps:

[0024] The graphene oxide is dispersed in N, N-dimethylformamide and ultrasonically treated for 25-35 minutes, and then trimethylamine is added, and then heated to 105-115°C under a nitrogen atmosphere and maintained for 25-35 minutes, and the fluorine-containing compound dissolved in N, N-dimethylformamide is continued to be added, and the reaction is carried out for 5.5-6.5 hours. After filtering, it is washed with N, N-dimethylformamide, tetrahydrofuran and ethanol in turn, and finally vacuum dried at 55-65°C to obtain fluorinated modified graphene oxide.

[0025] In the above reaction process, graphene oxide has hydroxyl groups, epoxy groups and carboxyl groups, and the fluorine-containing compound has hydroxyl groups, amino groups and fluorine atoms. The hydroxyl groups in the fluorine-containing compound can be combined with the hydroxyl groups on the graphene oxide, and the amino groups in the fluorine-containing compound can also be combined with the epoxy groups on the graphene oxide. The fluorine-containing compound is grafted onto the surface of the graphene oxide to obtain fluorinated modified graphene oxide.

[0026] Furthermore, the mass ratio of the graphene oxide to N,N-dimethylformamide is 0.8-1.2:90-110.

[0027] Furthermore, the fluorine-containing compound is composed of hexafluoro-1,10-decanediol and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl mixed in a mass ratio of 0.6-0.7:0.2-0.4.

[0028] Furthermore, step S1 is specifically as follows:

[0029] The fluorinated modified graphene oxide was added to acetonitrile and ultrasonically treated for 1-1.5 hours, then added to the pretreated fiber sleeve and soaked at room temperature for 11-13 hours. After filtering, it was washed with acetonitrile, ethanol and deionized water in sequence, and finally dried at 80-90°C for 10-12 hours to form an insulating coating.

[0030] Furthermore, the mass ratio of the fluorinated modified graphene oxide, acetonitrile, and pretreated fiber sleeve is 1-2:50-60:4-5.

[0031] Furthermore, in step S2, the method for preparing the silicon polymer comprises the following steps:

[0032] Sodium hydroxide is added to deionized water and stirred until completely dissolved, silicon dioxide is added and stirred for 2.5-3.5 hours, hydrochloric acid solution, tetrahydrofuran and sodium chloride are added, and the stirring reaction is continued for 25-35 minutes, and then centrifuged for 10-15 minutes, anhydrous magnesium sulfate is added for dehydration, and the tetrahydrofuran is removed by filtering and rotary evaporation to obtain a silicon polymer.

[0033] Furthermore, the mass ratio of the sodium hydroxide, deionized water, silicon dioxide, hydrochloric acid solution, tetrahydrofuran and sodium chloride is 0.8-1.2:55-65:2.9-3.1:55-65:170-180:35-36.

[0034] Furthermore, step S2 is specifically as follows:

[0035] The silicon polymer is dissolved in tetrahydrofuran to obtain a silicon solution, and the silicon solution is coated on the surface of the insulating coating formed in step S1, and then heated at 40-50°C for 15-25 minutes, heated at 90-100°C for 5-10 minutes, and finally dried at 140-150°C for 8-12 minutes to form an intermediate layer.

[0036] Furthermore, the mass ratio of the silicon polymer to tetrahydrofuran is 1:80-120.

[0037] Furthermore, the coating has a thickness of 20-30 μm.

[0038] Furthermore, step A1 is specifically as follows:

[0039] Dichloromethane, hydroxyethyl methacrylate and triethylamine are mixed and placed in an ice water bath, and then a phosphorus-containing compound is added. The mixture is stirred and reacted at room temperature for 4-5 hours. After the reaction is completed, the mixture is washed with a dilute hydrochloric acid aqueous solution and a saturated sodium bicarbonate solution in sequence, and dehydrated with anhydrous magnesium sulfate. Dichloromethane is removed by rotary evaporation, and finally vacuum dried at 55-65°C for 9-11 hours to obtain a flame retardant composite.

[0040] In the above reaction process, hydroxyethyl methacrylate has a hydroxyl group and a carbon-carbon double bond, and the phosphorus-containing compound has a chlorine atom, a hydroxyl group and a carboxyl group. The hydroxyl group in hydroxyethyl methacrylate can combine with the chlorine atom in the phosphorus-containing compound to obtain a flame retardant composite.

[0041] Furthermore, the mass ratio of the dichloromethane, hydroxyethyl methacrylate and triethylamine is 140-150:5.7-5.9:5-5.2.

[0042] Furthermore, the phosphorus-containing compound is composed of a mixture of diphenylphosphinoyl chloride and 2-carboxyethylphenylphosphorous acid in a mass ratio of 0.8-1:0.4-0.5.

[0043] Furthermore, step A2 is specifically as follows:

[0044] Add the flame retardant composite and vinyl silsesquioxane into tetrahydrofuran and mix evenly, then add azobisisobutyronitrile under nitrogen atmosphere, stir and reflux for 7-9 hours, remove tetrahydrofuran by rotary evaporation, add into anhydrous ether, separate the precipitate, and vacuum dry at 55-65°C for 11-13 hours to obtain a flame retardant reinforced material.

[0045] During the above reaction process, the flame retardant compound has carbon-carbon double bonds, and the vinyl-containing silsesquioxane also has carbon-carbon double bonds. The carbon-carbon double bonds in the flame retardant compound can be combined with the carbon-carbon double bonds in the vinyl-containing silsesquioxane through a free radical polymerization reaction. The flame retardant compound and the vinyl-containing silsesquioxane are combined together to obtain a flame retardant reinforced material.

[0046] Furthermore, the mass ratio of the flame retardant composite, the vinyl silsesquioxane and tetrahydrofuran is 6-6.5:1.8-2:240-250.

[0047] Furthermore, the preparation method of vinyl silsesquioxane comprises the following steps:

[0048] 3-(Methacryloyloxy)propyltrimethoxysilane, phenyltrimethoxysilane and acetone are mixed, then heated to 55-65°C, potassium hydroxide aqueous solution is added, reacted at 55-65°C and maintained for 24 hours. After the reaction is completed, it is cooled to room temperature, neutralized with acetic acid, washed with deionized water, and acetone is removed by reduced pressure distillation to finally obtain vinyl-containing silsesquioxane.

[0049] Furthermore, the mass ratio of the 3-(methacryloyloxy)propyltrimethoxysilane, phenyltrimethoxysilane and acetone is 24-25:19-20:75-85.

[0050] Furthermore, step S3 is specifically as follows:

[0051] A flame retardant reinforcing material is added to tetrahydrofuran to obtain a reinforcing solution, and the reinforcing solution is coated on the surface of the intermediate layer formed in step S2, and then heated at 45-55°C for 20-30 minutes, heated at 95-105°C for 10-15 minutes, and finally dried at 130-140°C for 10-15 minutes to form a refractory coating, thereby forming a refractory insulating inorganic fiber sleeve consisting of a pretreated fiber sleeve, an insulating coating, an intermediate layer and a refractory coating.

[0052] Furthermore, the mass ratio of the flame retardant reinforcing material to tetrahydrofuran is 1:40-50.

[0053] Furthermore, the coating has a thickness of 40-50 μm.

[0054] Beneficial effects of the present invention:

[0055] (1) In the technical scheme of the present invention, a flame retardant composite is obtained by combining a phosphorus-containing compound with hydroxyethyl methacrylate; the phosphorus-containing compound is composed of a mixture of diphenylphosphinoyl chloride and 2-carboxyethylphenylphosphinoyl, diphenylphosphinoyl chloride and 2-carboxyethylphenylphosphinoyl not only have good flame retardant properties, but also have functional groups that can be well combined with hydroxyethyl methacrylate, and can also provide reaction sites for subsequent reactions; the flame retardant composite is combined with vinyl-containing silsesquioxane through free radical polymerization to obtain a flame retardant reinforcement material; vinyl-containing silsesquioxane has the advantages of molecular stability, non-toxicity and environmental protection, its inorganic silicon core structure can improve the mechanical strength and fire resistance of the polymer, and the organic peripheral structure can improve the compatibility and reactivity with the polymer, the flame retardant composite is combined with vinyl-containing silsesquioxane, not only has good bonding force, but the two can also play a synergistic flame retardant role, thereby further improving the fire resistance, thermal stability and mechanical properties of the inorganic fiber sleeve.

[0056] (2) In the technical solution of the present invention, fluorinated modified graphene oxide is prepared by grafting graphene oxide with fluorine-containing compounds; the fluorine-containing compound is composed of a mixture of hexafluoro-1,10-decanediol and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl. The fluorine-containing compound contains more fluorine atoms and has good hydrophobic properties. Grafting the fluorine-containing compound onto the surface of graphene oxide can not only improve the dispersibility of graphene oxide and prevent its agglomeration, but also increase its hydrophobic properties and thermal stability. At the same time, graphene oxide has high mechanical properties, excellent thermal stability and good insulating properties. Combining the fluorine-containing compound with graphene oxide has good bonding force, which can further improve the mechanical properties and thermal stability of the inorganic fiber sleeve. The invention relates to a method for improving the insulation performance of the fiber sleeve and the fiber sleeving. The method comprises the following steps: applying a layer of fluorinated modified graphene oxide on the surface of the pretreated fiber sleeve to form an insulating coating; the functional groups in the fluorinated modified graphene oxide have good bonding force with the functional groups in the pretreated fiber sleeve, thereby increasing the adhesion between the fluorinated modified graphene oxide and the pretreated fiber sleeve; coating a layer of silicone polymer on the surface of the insulating coating to form an intermediate layer; the silicone polymer has good adhesion, and coating the silicone polymer between the insulating coating and the refractory coating can increase the adhesion between the two and make the bonding more firm; coating a layer of flame retardant reinforcing material on the surface of the intermediate layer to form a refractory coating, and the flame retardant reinforcing material and the silicone polymer also have good bonding force, thereby increasing the adhesion between the intermediate layer and the refractory coating.

[0057] (3) In the technical scheme of the present invention, a flame retardant reinforcing material is obtained by combining a phosphorus-containing compound with hydroxyethyl methacrylate and then combining it with a vinyl-containing silsesquioxane; fluorinated modified graphene oxide is obtained by grafting graphene oxide with a fluorine-containing compound; a layer of fluorinated modified graphene oxide is dip-coated on the surface of a pretreated fiber sleeve to form an insulating coating, and then a layer of silicon polymer is coated to form an intermediate layer, and finally a layer of flame retardant reinforcing material is coated to form a fire-resistant coating, thereby forming a fire-resistant and insulating inorganic fiber sleeve consisting of a pretreated fiber sleeve, an insulating coating, an intermediate layer and a fire-resistant coating; the prepared inorganic fiber sleeve has good fire resistance, insulation, thermal stability and mechanical properties, extends the service life of the fiber sleeve, and has good overall comprehensive performance. DETAILED DESCRIPTION

[0058] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] The specific parameters of the raw materials used in the present invention are as follows:

[0060] Graphene oxide, No.: XF002-2, provided by Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.; Hexadecanediol, CAS No.: 754-96-1, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.; 2,2'-Bis(trifluoromethyl)-4,4'-diaminobiphenyl, CAS No.: 341-58-2, provided by Shanghai MacLean Biochemical Technology Co., Ltd.; Diphenylphosphinoyl chloride, CAS No.: 1499-21-4, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.; 2-Carboxyethylphenylphosphinoyl, CAS No.: 14657-64-8, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.

[0061] Example 1

[0062] Preparation of fire-resistant and insulating inorganic fiber sleeves, the specific steps are:

[0063] S1: According to the mass ratio of fluorinated modified graphene oxide, acetonitrile and pretreated fiber sleeve being 1:50:4, the fluorinated modified graphene oxide was added to acetonitrile and ultrasonically treated for 1 hour, then added to the pretreated fiber sleeve and soaked at room temperature for 11 hours, filtered, washed with acetonitrile, ethanol and deionized water in turn (the mass of acetonitrile, ethanol and deionized water was 10 times that of the fluorinated modified graphene oxide), and finally dried at 80°C for 10 hours to form an insulating coating;

[0064] The preparation method of the pretreated fiber sleeve comprises the following steps:

[0065] According to the mass ratio of the fiber sleeve to the sodium hydroxide solution of 1:20, the fiber sleeve is placed in a 0.1 mol / L sodium hydroxide solution, then heated to 90°C and maintained for 25 minutes, then washed with deionized water (the mass of the deionized water is 80wt% of the mass of the sodium hydroxide solution), and dried at 80°C for 20 minutes to obtain an alkalized fiber sleeve, according to the mass ratio of the alkalized fiber sleeve to the ethanol / deionized water solution of 0.8:40, the alkalized fiber sleeve and the ethanol / deionized water solution (the volume ratio of ethanol to deionized water is 9:1) are mixed, and a silane coupling agent is added (the mass of the silane coupling agent is 3wt% of the mass of the alkalized fiber sleeve), refluxed at 115°C for 1 hour, and then dried at room temperature for 24 hours to obtain a pretreated fiber sleeve, wherein the silane coupling agent is composed of 3-(2-aminoethylamino)propylmethyldimethoxysilane and γ-glycidyloxypropyltrimethoxysilane mixed in a mass ratio of 0.7:0.3;

[0066] The preparation method of the fiber sleeve comprises the following steps:

[0067] The basalt fiber is woven into a basalt fiber sleeve embryo, and then passed through an embryo machine to make the tube round, and then passed through a high-temperature dewaxing furnace, dewaxing and shaping at 500℃ for 60 minutes to obtain a fiber sleeve;

[0068] The preparation method of fluorinated modified graphene oxide comprises the following steps:

[0069] According to the mass ratio of graphene oxide to N, N-dimethylformamide being 0.8:90, graphene oxide was dispersed in N, N-dimethylformamide and ultrasonically treated for 25 min (ultrasonic frequency was 40 kHz and ultrasonic power was 100 W), and then trimethylamine (the mass of trimethylamine was 3 wt% of the mass of N, N-dimethylformamide) was added, and then heated to 105° C. under a nitrogen atmosphere and maintained for 25 min, and a fluorine-containing compound dissolved in N, N-dimethylformamide (the mass of the fluorine-containing compound was 10 wt% of the mass of graphene oxide) was added. The mass of N, N-dimethylformamide is 50 times that of graphene oxide), and react for 5.5 hours, filter, wash with N, N-dimethylformamide, tetrahydrofuran and ethanol in sequence (the mass of N, N-dimethylformamide, tetrahydrofuran and ethanol is 15 times that of graphene oxide), and finally vacuum dry at 55°C for 24 hours to obtain fluorinated modified graphene oxide, wherein the fluorine-containing compound is composed of hexadecylfluoro-1,10-decanediol and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl mixed in a mass ratio of 0.6:0.2;

[0070] S2: dissolving the silicon polymer in tetrahydrofuran at a mass ratio of 1:80 to obtain a silicon solution, coating the silicon solution on the surface of the insulating coating formed in step S1 with a coating thickness of 20 μm, then heating at 40° C. for 15 min, heating at 90° C. for 5 min, and finally drying at 140° C. for 8 min to form an intermediate layer;

[0071] The method for preparing the silicon polymer comprises the following steps:

[0072] According to the mass ratio of sodium hydroxide, deionized water, silicon dioxide, hydrochloric acid solution, tetrahydrofuran and sodium chloride being 0.8:55:2.9:55:170:34, sodium hydroxide is added to deionized water and stirred until completely dissolved, silicon dioxide is added and stirred for 2.5 hours, and then 2 mol / L hydrochloric acid solution, tetrahydrofuran and sodium chloride are added, and the stirring reaction is continued for 25 minutes, and then centrifuged at a speed of 1000 rpm for 15 minutes, the supernatant is collected, anhydrous magnesium sulfate is added for dehydration, and the tetrahydrofuran is removed by filtering and rotary evaporation to obtain a silicon polymer;

[0073] S3: adding the flame retardant reinforcement material to tetrahydrofuran in a mass ratio of 1:40 to obtain a reinforcement solution, coating the reinforcement solution on the surface of the intermediate layer formed in step S2, with a coating thickness of 40 μm, then heating at 45° C. for 20 min, heating at 95° C. for 10 min, and finally drying at 130° C. for 10 min to form a fire-resistant coating, thereby forming a fire-resistant and insulating inorganic fiber sleeve consisting of a pretreated fiber sleeve, an insulating coating, an intermediate layer and a fire-resistant coating;

[0074] Preparation of flame retardant reinforcement material, the specific steps are:

[0075] A1: Dichloromethane, hydroxyethyl methacrylate and triethylamine are mixed in a mass ratio of 140:5.7:5, and placed in an ice-water bath. Then, a phosphorus-containing compound (the mass of the phosphorus-containing compound is 2.3 times the mass of hydroxyethyl methacrylate) is added, and the mixture is stirred for reaction at room temperature for 4 hours. After the reaction is completed, the mixture is washed with 8% dilute hydrochloric acid aqueous solution and 10% saturated sodium bicarbonate solution in sequence (the mass of the dilute hydrochloric acid aqueous solution and the mass of the saturated sodium bicarbonate solution are both 3 times the mass of triethylamine), and after dehydration with anhydrous magnesium sulfate, dichloromethane is removed by rotary evaporation, and finally vacuum dried at 55°C for 9 hours to obtain a flame retardant composite, wherein the phosphorus-containing compound is composed of diphenylphosphinyl chloride and 2-carboxyethylphenylphosphinyl chloride mixed in a mass ratio of 0.8:0.4;

[0076] A2: According to the mass ratio of the flame retardant compound, the vinyl silsesquioxane and tetrahydrofuran being 6:1.8:240, the flame retardant compound and the vinyl silsesquioxane were added to tetrahydrofuran and mixed evenly, and then azobisisobutyronitrile (the mass of azobisisobutyronitrile was 0.7wt% of the mass of the flame retardant compound) was added under nitrogen atmosphere, and stirred and refluxed for 7h, and the tetrahydrofuran was removed by rotary evaporation, and then added to anhydrous ether (the mass of anhydrous ether was 10wt% of the mass of tetrahydrofuran), and after separating the precipitate, it was vacuum dried at 55°C for 11h to obtain a flame retardant reinforced material;

[0077] Wherein, the preparation method of vinyl silsesquioxane comprises the following steps:

[0078] According to the mass ratio of 3-(methacryloyloxy)propyltrimethoxysilane, phenyltrimethoxysilane and acetone of 24:19:75, 3-(methacryloyloxy)propyltrimethoxysilane, phenyltrimethoxysilane and acetone were mixed, then heated to 55°C, 20 mg / mL potassium hydroxide aqueous solution was added, reacted at 55°C and maintained for 24 hours. After the reaction was completed, it was cooled to room temperature, neutralized with acetic acid (the mass of acetic acid was 20 wt% of the mass of acetone), washed with deionized water for 3 times (the mass of deionized water each time was 15 wt% of the mass of acetone), and acetone was removed by reduced pressure distillation to finally obtain vinyl-containing silsesquioxane.

[0079] Example 2

[0080] Preparation of fire-resistant and insulating inorganic fiber sleeves, the specific steps are:

[0081] S1: According to the mass ratio of fluorinated modified graphene oxide, acetonitrile and pretreated fiber sleeve of 1.5:55:4.5, the fluorinated modified graphene oxide was added to acetonitrile and ultrasonically treated for 1.3 hours, and then added to the pretreated fiber sleeve and soaked at room temperature for 12 hours. After filtering, it was washed with acetonitrile, ethanol and deionized water in turn (the mass of acetonitrile, ethanol and deionized water was 10 times that of the fluorinated modified graphene oxide), and finally dried at 85°C for 11 hours to form an insulating coating;

[0082] The preparation method of the pretreated fiber sleeve comprises the following steps:

[0083] According to the mass ratio of the fiber sleeve to the sodium hydroxide solution of 1:25, the fiber sleeve is placed in a 0.1 mol / L sodium hydroxide solution, then heated to 95°C and maintained for 30 minutes, then washed with deionized water (the mass of the deionized water is 80wt% of the mass of the sodium hydroxide solution), and dried at 85°C for 25 minutes to obtain an alkalized fiber sleeve, according to the mass ratio of the alkalized fiber sleeve to the ethanol / deionized water solution of 1:45, the alkalized fiber sleeve and the ethanol / deionized water solution (the volume ratio of ethanol to deionized water is 9:1) are mixed, and a silane coupling agent is added (the mass of the silane coupling agent is 3wt% of the mass of the alkalized fiber sleeve), refluxed at 120°C for 1.5 hours, and then dried at room temperature for 24 hours to obtain a pretreated fiber sleeve, wherein the silane coupling agent is composed of 3-(2-aminoethylamino)propylmethyldimethoxysilane and γ-glycidyloxypropyltrimethoxysilane mixed in a mass ratio of 0.75:0.35;

[0084] The preparation method of the fiber sleeve comprises the following steps:

[0085] The basalt fiber is woven into a basalt fiber sleeve embryo, and then passed through an embryo machine to make the tube round, and then passed through a high-temperature dewaxing furnace, dewaxing and shaping at 520℃ for 50 minutes to obtain a fiber sleeve;

[0086] The preparation method of fluorinated modified graphene oxide comprises the following steps:

[0087] According to the mass ratio of graphene oxide to N, N-dimethylformamide being 1:100, graphene oxide was dispersed in N, N-dimethylformamide and ultrasonically treated for 30 min (ultrasonic frequency was 40 kHz and ultrasonic power was 100 W), and then trimethylamine (the mass of trimethylamine was 3 wt% of the mass of N, N-dimethylformamide) was added, and then heated to 110° C. under a nitrogen atmosphere and maintained for 30 min, and a fluorine-containing compound dissolved in N, N-dimethylformamide (the mass of the fluorine-containing compound was 10 wt% of the mass of graphene oxide) was added. The mass of N, N-dimethylformamide is 50 times that of graphene oxide), and react for 6 hours, filter, wash with N, N-dimethylformamide, tetrahydrofuran and ethanol in sequence (the mass of N, N-dimethylformamide, tetrahydrofuran and ethanol is 15 times that of graphene oxide), and finally vacuum dry at 60°C for 24 hours to obtain fluorinated modified graphene oxide, wherein the fluorine-containing compound is composed of hexadecylfluoro-1,10-decanediol and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl mixed in a mass ratio of 0.65:0.3;

[0088] S2: dissolving the silicon polymer in tetrahydrofuran at a mass ratio of 1:100 to obtain a silicon solution, coating the silicon solution on the surface of the insulating coating formed in step S1 with a coating thickness of 25 μm, then heating at 45° C. for 20 min, heating at 95° C. for 8 min, and finally drying at 145° C. for 10 min to form an intermediate layer;

[0089] The method for preparing the silicon polymer comprises the following steps:

[0090] According to the mass ratio of sodium hydroxide, deionized water, silicon dioxide, hydrochloric acid solution, tetrahydrofuran and sodium chloride being 1:60:3:60:175:34.5, sodium hydroxide is added to deionized water and stirred until completely dissolved, silicon dioxide is added and stirred for 3 hours, and then 2 mol / L hydrochloric acid solution, tetrahydrofuran and sodium chloride are added, and the stirring reaction is continued for 30 minutes, and then centrifuged at a speed of 1500 rpm for 12 minutes, the supernatant is collected, anhydrous magnesium sulfate is added for dehydration, and the tetrahydrofuran is removed by filtering and rotary evaporation to obtain a silicon polymer;

[0091] S3: adding the flame retardant reinforcement material to tetrahydrofuran at a mass ratio of 1:45 to obtain a reinforcement solution, coating the reinforcement solution on the surface of the intermediate layer formed in step S2, with a coating thickness of 45 μm, then heating at 50° C. for 25 min, heating at 100° C. for 12 min, and finally drying at 135° C. for 12 min to form a fire-resistant coating, thereby forming a fire-resistant and insulating inorganic fiber sleeve consisting of a pretreated fiber sleeve, an insulating coating, an intermediate layer and a fire-resistant coating;

[0092] Preparation of flame retardant reinforcement material, the specific steps are:

[0093] A1: Dichloromethane, hydroxyethyl methacrylate and triethylamine were mixed in a mass ratio of 145:5.8:5.1, and placed in an ice-water bath. Then, a phosphorus-containing compound (the mass of the phosphorus-containing compound was 2.3 times the mass of hydroxyethyl methacrylate) was added, and the mixture was stirred at room temperature for 4.5 hours. After the reaction was completed, the mixture was washed with 8% dilute hydrochloric acid aqueous solution and 10% saturated sodium bicarbonate solution (the mass of the dilute hydrochloric acid aqueous solution and the saturated sodium bicarbonate solution were both 3 times the mass of triethylamine), and the mixture was dehydrated with anhydrous magnesium sulfate. Dichloromethane was removed by rotary evaporation, and finally vacuum dried at 60°C for 10 hours to obtain a flame retardant composite, wherein the phosphorus-containing compound was composed of diphenylphosphinyl chloride and 2-carboxyethylphenylphosphinyl chloride mixed in a mass ratio of 0.9:0.45;

[0094] A2: According to the mass ratio of the flame retardant composite, vinyl silsesquioxane and tetrahydrofuran being 6.3:1.9:245, the flame retardant composite and the vinyl silsesquioxane were added to tetrahydrofuran and mixed evenly, and then azobisisobutyronitrile (the mass of azobisisobutyronitrile was 0.7wt% of the mass of the flame retardant composite) was added under nitrogen atmosphere, and stirred and refluxed for 8h, and the tetrahydrofuran was removed by rotary evaporation, and then added to anhydrous ether (the mass of anhydrous ether was 10wt% of the mass of tetrahydrofuran), and after separating the precipitate, it was vacuum dried at 60°C for 12h to obtain a flame retardant reinforced material;

[0095] Wherein, the preparation method of vinyl silsesquioxane comprises the following steps:

[0096] According to the mass ratio of 3-(methacryloyloxy)propyltrimethoxysilane, phenyltrimethoxysilane and acetone of 24.5:19.5:80, 3-(methacryloyloxy)propyltrimethoxysilane, phenyltrimethoxysilane and acetone were mixed, then heated to 60°C, 20 mg / mL potassium hydroxide aqueous solution was added, reacted at 60°C and maintained for 24 hours. After the reaction was completed, it was cooled to room temperature, neutralized with acetic acid (the mass of acetic acid was 20 wt% of the mass of acetone), washed with deionized water for 3 times (the mass of deionized water each time was 15 wt% of the mass of acetone), and acetone was removed by reduced pressure distillation to obtain vinyl-containing silsesquioxane.

[0097] Example 3

[0098] Preparation of fire-resistant and insulating inorganic fiber sleeves, the specific steps are:

[0099] S1: According to the mass ratio of fluorinated modified graphene oxide, acetonitrile and pretreated fiber sleeve being 2:60:5, the fluorinated modified graphene oxide was added to acetonitrile and ultrasonically treated for 1.5 hours, then added to the pretreated fiber sleeve and soaked at room temperature for 13 hours. After filtering, it was washed with acetonitrile, ethanol and deionized water in turn (the mass of acetonitrile, ethanol and deionized water was 10 times that of the fluorinated modified graphene oxide), and finally dried at 90°C for 12 hours to form an insulating coating;

[0100] The preparation method of the pretreated fiber sleeve comprises the following steps:

[0101] According to the mass ratio of the fiber sleeve to the sodium hydroxide solution of 1:30, the fiber sleeve is placed in a 0.1 mol / L sodium hydroxide solution, then heated to 100°C and maintained for 35 minutes, then washed with deionized water (the mass of the deionized water is 80wt% of the mass of the sodium hydroxide solution), and dried at 90°C for 30 minutes to obtain an alkalized fiber sleeve, according to the mass ratio of the alkalized fiber sleeve to the ethanol / deionized water solution of 1.2:50, the alkalized fiber sleeve and the ethanol / deionized water solution (the volume ratio of ethanol to deionized water is 9:1) are mixed, and a silane coupling agent is added (the mass of the silane coupling agent is 3wt% of the mass of the alkalized fiber sleeve), refluxed at 125°C for 2 hours, and then dried at room temperature for 24 hours to obtain a pretreated fiber sleeve, wherein the silane coupling agent is composed of 3-(2-aminoethylamino)propylmethyldimethoxysilane and γ-glycidyloxypropyltrimethoxysilane mixed in a mass ratio of 0.8:0.4;

[0102] The preparation method of the fiber sleeve comprises the following steps:

[0103] The basalt fiber is woven into a basalt fiber sleeve embryo, and then passed through an embryo machine to make the tube round, and then passed through a high-temperature dewaxing furnace, dewaxing and shaping at 550℃ for 40 minutes to obtain a fiber sleeve;

[0104] The preparation method of fluorinated modified graphene oxide comprises the following steps:

[0105] According to the mass ratio of graphene oxide to N, N-dimethylformamide being 1.2:110, graphene oxide was dispersed in N, N-dimethylformamide and ultrasonically treated for 35 min (ultrasonic frequency was 40 kHz and ultrasonic power was 100 W), and then trimethylamine (the mass of trimethylamine was 3 wt% of the mass of N, N-dimethylformamide) was added, and then heated to 115° C. under a nitrogen atmosphere and maintained for 35 min, and a fluorine-containing compound dissolved in N, N-dimethylformamide (the mass of the fluorine-containing compound was 10 wt% of the mass of graphene oxide) was added. The mass of N, N-dimethylformamide is 50 times that of graphene oxide), and react for 6.5 hours, filter, wash with N, N-dimethylformamide, tetrahydrofuran and ethanol in sequence (the mass of N, N-dimethylformamide, tetrahydrofuran and ethanol is 15 times that of graphene oxide), and finally vacuum dry at 65°C for 24 hours to obtain fluorinated modified graphene oxide, wherein the fluorine-containing compound is composed of hexadecylfluoro-1,10-decanediol and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl mixed in a mass ratio of 0.7:0.4;

[0106] S2: dissolving the silicon polymer in tetrahydrofuran at a mass ratio of 1:120 to obtain a silicon solution, coating the silicon solution on the surface of the insulating coating formed in step S1, with a coating thickness of 30 μm, then heating at 50° C. for 25 min, heating at 100° C. for 10 min, and finally drying at 150° C. for 12 min to form an intermediate layer;

[0107] The method for preparing the silicon polymer comprises the following steps:

[0108] According to the mass ratio of sodium hydroxide, deionized water, silicon dioxide, hydrochloric acid solution, tetrahydrofuran and sodium chloride being 1.2:65:3.1:65:180:35, sodium hydroxide is added to deionized water and stirred until completely dissolved, silicon dioxide is added and stirred for 3.5 hours, and then 2 mol / L hydrochloric acid solution, tetrahydrofuran and sodium chloride are added, and the stirring reaction is continued for 35 minutes, and then centrifuged at a speed of 2000 rpm for 10 minutes, the supernatant is collected, anhydrous magnesium sulfate is added for dehydration, and the tetrahydrofuran is removed by filtering and rotary evaporation to obtain a silicon polymer;

[0109] S3: adding the flame retardant reinforcement material to tetrahydrofuran in a mass ratio of 1:50 to obtain a reinforcement solution, coating the reinforcement solution on the surface of the intermediate layer formed in step S2, with a coating thickness of 50 μm, then heating at 55° C. for 30 min, heating at 105° C. for 15 min, and finally drying at 140° C. for 15 min to form a fire-resistant coating, thereby forming a fire-resistant and insulating inorganic fiber sleeve consisting of a pretreated fiber sleeve, an insulating coating, an intermediate layer and a fire-resistant coating;

[0110] Preparation of flame retardant reinforcement material, the specific steps are:

[0111] A1: Dichloromethane, hydroxyethyl methacrylate and triethylamine were mixed in a mass ratio of 150:5.9:5.2, and placed in an ice-water bath. Then, a phosphorus-containing compound (the mass of the phosphorus-containing compound was 2.3 times the mass of hydroxyethyl methacrylate) was added, and the mixture was stirred for reaction at room temperature for 5 hours. After the reaction was completed, the mixture was washed with 8% dilute hydrochloric acid aqueous solution and 10% saturated sodium bicarbonate solution (the mass of the dilute hydrochloric acid aqueous solution and the saturated sodium bicarbonate solution were both 3 times the mass of triethylamine), and the mixture was dehydrated with anhydrous magnesium sulfate. Dichloromethane was removed by rotary evaporation, and finally vacuum dried at 65°C for 11 hours to obtain a flame retardant composite, wherein the phosphorus-containing compound was composed of diphenylphosphinyl chloride and 2-carboxyethylphenylphosphinyl chloride mixed in a mass ratio of 1:0.5;

[0112] A2: According to the mass ratio of the flame retardant compound, the vinyl silsesquioxane and tetrahydrofuran being 6.5:2:250, the flame retardant compound and the vinyl silsesquioxane were added to tetrahydrofuran and mixed evenly, and then azobisisobutyronitrile (the mass of azobisisobutyronitrile was 0.7wt% of the mass of the flame retardant compound) was added under nitrogen atmosphere, and stirred and refluxed for 9h, and the tetrahydrofuran was removed by rotary evaporation, and then added to anhydrous ether (the mass of anhydrous ether was 10wt% of the mass of tetrahydrofuran), and after separating the precipitate, it was vacuum dried at 65°C for 13h to obtain a flame retardant reinforced material;

[0113] Wherein, the preparation method of vinyl silsesquioxane comprises the following steps:

[0114] According to the mass ratio of 3-(methacryloyloxy)propyltrimethoxysilane, phenyltrimethoxysilane and acetone of 25:20:85, 3-(methacryloyloxy)propyltrimethoxysilane, phenyltrimethoxysilane and acetone were mixed, then heated to 65°C, 20 mg / mL potassium hydroxide aqueous solution was added, reacted at 65°C and maintained for 24 hours. After the reaction was completed, it was cooled to room temperature, neutralized with acetic acid (the mass of acetic acid was 20 wt% of the mass of acetone), washed with deionized water for 3 times (the mass of deionized water each time was 15 wt% of the mass of acetone), and acetone was removed by reduced pressure distillation to obtain vinyl-containing silsesquioxane.

[0115] Comparative Example 1

[0116] The difference between this comparative example and Example 3 is that when preparing the fire-resistant insulating inorganic fiber sleeve, in step S1, the mass of the silane coupling agent in the pretreated fiber sleeve is replaced by 3-(2-aminoethylamino)propylmethyldimethoxysilane, and the remaining steps and raw materials are synchronized with Example 3;

[0117] The preparation method of the pretreated fiber sleeve comprises the following steps:

[0118] According to the mass ratio of the fiber sleeve to the sodium hydroxide solution of 1:30, the fiber sleeve is placed in a 0.1 mol / L sodium hydroxide solution, then heated to 100°C and maintained for 35 minutes, and then washed with deionized water (the mass of deionized water is 80wt% of the mass of the sodium hydroxide solution), and dried at 90°C for 30 minutes to obtain an alkalized fiber sleeve. According to the mass ratio of the alkalized fiber sleeve to the ethanol / deionized water solution of 1.2:50, the alkalized fiber sleeve and the ethanol / deionized water solution (the volume ratio of ethanol to deionized water is 9:1) are mixed, and 3-(2-aminoethylamino)propylmethyldimethoxysilane is added (the mass of 3-(2-aminoethylamino)propylmethyldimethoxysilane is 3wt% of the mass of the alkalized fiber sleeve), refluxed at 125°C for 2 hours, and then dried at room temperature for 24 hours to obtain a pretreated fiber sleeve.

[0119] Comparative Example 2

[0120] The difference between this comparative example and Example 3 is that when preparing the fire-resistant insulating inorganic fiber sleeve, in step S1, the pre-treated fiber sleeve is not treated with a silane coupling agent, and the remaining steps and raw materials are the same as those of Example 3;

[0121] The preparation method of the pretreated fiber sleeve comprises the following steps:

[0122] According to the mass ratio of the fiber sleeve to the sodium hydroxide solution of 1:30, the fiber sleeve was placed in a 0.1 mol / L sodium hydroxide solution, then heated to 100°C and maintained for 35 minutes, then washed with deionized water (the mass of the deionized water was 80wt% of the mass of the sodium hydroxide solution), and dried at 90°C for 30 minutes to obtain a pretreated fiber sleeve.

[0123] Comparative Example 3

[0124] The difference between this comparative example and Example 3 is that when preparing the fire-resistant insulating inorganic fiber sleeve, in step S1, the mass of the fluorine-containing compound in the fluorinated modified graphene oxide is replaced by hexafluoro-1,10-decanediol, and the remaining steps and raw materials are the same as those in Example 3;

[0125] The preparation method of fluorinated modified graphene oxide comprises the following steps:

[0126] According to the mass ratio of graphene oxide to N, N-dimethylformamide of 1.2:110, graphene oxide was dispersed in N, N-dimethylformamide and ultrasonically treated for 35 min (ultrasonic frequency of 40 kHz, ultrasonic power of 100 W), and then trimethylamine (the mass of trimethylamine is 3 wt% of the mass of N, N-dimethylformamide) was added, and then heated to 115 ° C in a nitrogen atmosphere and maintained for 35 min, and hexadecene dissolved in N, N-dimethylformamide was added. Fluoro-1,10-decanediol (the mass of hexafluoro-1,10-decanediol is 10wt% of the mass of graphene oxide, and the mass of N,N-dimethylformamide is 50 times of the mass of graphene oxide), and react for 6.5h, filter, wash with N,N-dimethylformamide, tetrahydrofuran and ethanol in turn (the mass of N,N-dimethylformamide, tetrahydrofuran and ethanol are all 15 times of the mass of graphene oxide), and finally vacuum dry at 65°C for 24h to obtain fluorinated modified graphene oxide.

[0127] Comparative Example 4

[0128] The difference between this comparative example and Example 3 is that when preparing the fire-resistant insulating inorganic fiber sleeve, in step S2, the mass of silicon polymer is replaced by silica sol, and the remaining steps and raw materials are synchronized with Example 3;

[0129] S2: coating the insulating coating surface formed in step S1 with silica sol, with a coating thickness of 30 μm, then heating at 50° C. for 25 min, heating at 100° C. for 10 min, and finally drying at 150° C. for 12 min to form an intermediate layer.

[0130] Comparative Example 5

[0131] The difference between this comparative example and Example 3 is that when preparing the flame retardant reinforcement material, the phosphorus-containing compound in step A1 is replaced by diphenylphosphine chloride, and the remaining steps and raw materials are the same as those in Example 3;

[0132] A1: Dichloromethane, hydroxyethyl methacrylate and triethylamine were mixed in a mass ratio of 150:5.9:5.2, and placed in an ice-water bath. Then, diphenylphosphinyl chloride was added (the mass of diphenylphosphinyl chloride was 2.3 times the mass of hydroxyethyl methacrylate), and the mixture was stirred at room temperature for 5 hours. After the reaction was completed, the mixture was washed with 8% dilute hydrochloric acid aqueous solution and 10% saturated sodium bicarbonate solution in sequence (the mass of the dilute hydrochloric acid aqueous solution and the mass of the saturated sodium bicarbonate solution were both 3 times the mass of triethylamine), and after dehydration with anhydrous magnesium sulfate, dichloromethane was removed by rotary evaporation, and finally vacuum dried at 65°C for 11 hours to obtain a flame retardant composite.

[0133] Comparative Example 6

[0134] The difference between this comparative example and Example 3 is that when preparing the flame retardant reinforcement material, the mass of the vinyl silsesquioxane in step A2 is replaced by octaisobutyl cage-shaped polysilsesquioxane, and the remaining steps and raw materials are the same as those in Example 3;

[0135] According to the mass ratio of the flame retardant composite, octaisobutyl cage-shaped polysilsesquioxane and tetrahydrofuran being 6.5:2:250, the flame retardant composite and octaisobutyl cage-shaped polysilsesquioxane are added to tetrahydrofuran and mixed evenly, and then azobisisobutyronitrile (the mass of azobisisobutyronitrile is 0.7wt% of the mass of the flame retardant composite) is added under a nitrogen atmosphere, and the mixture is stirred and refluxed for 9 hours, and the tetrahydrofuran is removed by rotary evaporation, and then the mixture is added to anhydrous ether (the mass of anhydrous ether is 10wt% of the mass of tetrahydrofuran). After separating the precipitate, the mixture is vacuum dried at 65°C for 13 hours to obtain a flame retardant reinforced material.

[0136] The fire-resistant and insulating inorganic fiber sleeves prepared in Examples 1-3 and Comparative Examples 1-6 were tested for fire resistance, insulation and mechanical properties; Fire resistance test: The flame retardant grade test was performed according to UL 94 standard, and the fire resistance was characterized by the flame retardant grade; Insulation test: A withstand voltage tester was used for testing, and a bare copper rod with a wire gauge of 3.35mm×8.5mm and a length of 300mm was used to cover the fire-resistant and insulating inorganic fiber sleeves prepared in Examples 1-3 and Comparative Examples 1-6, respectively, and each sample was coated with aluminum foil and then subjected to an AC power frequency voltage breakdown test to test its breakdown voltage, and the insulation performance was characterized by the breakdown voltage; Mechanical property test: The fire-resistant and insulating inorganic fiber sleeves prepared in Examples 1-3 and Comparative Examples 1-6 were subjected to a low-temperature strength test, and each sample was placed at -10°C for 24h, and a certain same cross-section was defined as a winding surface, and the sample was bent back and forth 90° for 10 consecutive times to observe whether the winding surface was damaged or broken, and the mechanical properties were characterized by low-temperature strength. The test results are shown in Table 1 below:

[0137] Table 1 Performance parameters of fire-resistant and insulating inorganic fiber sleeves obtained in Examples 1-3 and Comparative Examples 1-6

[0138] project Flame retardant grade <![CDATA[Breakdown voltage( kV )]]> Low temperature (-10℃) strength Example 1 V-0 9.8 Hard, no cracking on curved surface Example 2 V-0 9.9 Hard, no cracking on curved surface Example 3 V-0 9.7 Hard, no cracks on curved surfaces Comparative Example 1 V-1 9.5 Brittle, slight fracture on the curved surface Comparative Example 2 V-1 9.1 Brittle, curved surface fracture Comparative Example 3 V-1 9.3 Brittle, slight fracture on the curved surface Comparative Example 4 V-1 9.0 Brittle, curved surface fracture Comparative Example 5 V-1 9.3 Brittle, slight fracture on the curved surface Comparative Example 6 V-1 9.2 Brittle, slight fracture on the curved surface

[0139] It can be seen from the data in Table 1 above that, by comparing Comparative Examples 1-2 with Example 3, it can be seen that the test results of preparing a fire-resistant and insulating inorganic fiber sleeve by replacing the mass of the silane coupling agent in the pretreated fiber sleeve with 3-(2-aminoethylamino)propylmethyldimethoxysilane or by not treating the pretreated fiber sleeve with the silane coupling agent are worse than those of Example 3, indicating that the fiber sleeve is treated with a silane coupling agent, and the silane coupling agent can be effectively grafted on the surface of the fiber sleeve, thereby enhancing the compatibility between the fiber sleeve and the insulating coating. The silane coupling agent composed of a mixture of 3-(2-aminoethylamino)propylmethyldimethoxysilane and γ-glycidyloxypropyltrimethoxysilane can better increase the adhesion between the fiber sleeve and the insulating coating, further improve the mechanical properties and thermal stability of the fiber sleeve, and also have a good effect on its fire resistance and insulation properties.

[0140] By comparing Comparative Example 3 with Example 3, it can be seen that the fluorine-containing compound in the fluorinated modified graphene oxide is replaced by hexafluoro-1,10-decanediol, and finally a fire-resistant and insulating inorganic fiber sleeve is prepared. The test result is worse than that of Example 3, indicating that the fluorinated compound composed of hexafluoro-1,10-decanediol and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl has more fluorine atoms and better hydrophobicity. It can not only be well combined with graphene oxide, increase the dispersibility of graphene oxide, but also can better improve the interface bonding force between the fluorinated modified graphene oxide and the pretreated fiber sleeve, enhance the adhesion between the two, and further improve the mechanical properties, fire resistance and insulation properties of the fiber sleeve;

[0141] From the comparison between Comparative Example 4 and Example 3, it can be seen that the test result of preparing the fire-resistant and insulating inorganic fiber sleeve by replacing the mass of silicon polymer with silica sol is worse than that of Example 3, indicating that the silicon polymer has good adhesion. The silicon polymer is coated between the insulating coating and the fire-resistant coating to form an intermediate layer, which can better improve the adhesion between the insulating coating and the fire-resistant coating, and further improve the fire resistance, insulation and mechanical properties of the inorganic fiber sleeve;

[0142] By comparing Comparative Examples 5-6 with Example 3, it can be seen that the fire-resistant and insulating inorganic fiber sheathing is prepared by replacing the mass of the phosphorus-containing compound in Step A1 with diphenylphosphinoyl chloride or replacing the mass of the vinyl silsesquioxane in Step A2 with octaisobutyl cage-shaped polysilsesquioxane. The test results are worse than those of Example 3, indicating that the phosphorus-containing compound composed of a mixture of diphenylphosphinoyl chloride and 2-carboxyethylphenylphosphorous acid has good flame retardant properties. Combining the phosphorus-containing compound with hydroxyethyl methacrylate can also provide reaction sites for subsequent reactions. Combining the flame retardant composite with vinyl silsesquioxane not only has good bonding strength, but also the vinyl silsesquioxane and the phosphorus-containing compound have a synergistic flame retardant effect, which can better improve the fire resistance, insulation and mechanical properties of the inorganic fiber sheathing.

[0143] It can be seen from Table 1 above that the fire-resistant and insulating inorganic fiber sleeves prepared in Examples 1-3 are compared with the fire-resistant and insulating inorganic fiber sleeves prepared in Comparative Examples 1-6. The phosphorus-containing compound is combined with hydroxyethyl methacrylate and then combined with vinyl silsesquioxane to obtain a flame retardant reinforcing material; the graphene oxide is grafted and modified by a fluorine-containing compound to obtain a fluorinated modified graphene oxide; a layer of fluorinated modified graphene oxide is dip-coated on the surface of the pretreated fiber sleeve to form an insulating coating, and then a layer of silicon polymer is coated to form an intermediate layer, and finally a layer of flame retardant reinforcing material is coated to form a fire-resistant coating, thereby forming a fire-resistant and insulating inorganic fiber sleeve consisting of a pretreated fiber sleeve, an insulating coating, an intermediate layer and a fire-resistant coating, which meets the test performance requirements, while the fire-resistant and insulating inorganic fiber sleeves prepared in Comparative Examples 1-6 do not meet the performance requirements. This shows that the fire-resistant and insulating inorganic fiber sleeves prepared by the present invention have good mechanical properties, fire resistance, insulation properties and thermal stability, extend the service life of the fiber sleeve, and have good comprehensive performance.

[0144] 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.

[0145] The above contents are merely examples and explanations of the present invention. Those skilled in the art 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 invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A process for preparing a fire-resistant and insulating inorganic fiber sleeve, characterized in that: The following steps are involved: S1: dip-coating a layer of fluorinated modified graphene oxide on the surface of the pretreated fiber sleeve to form an insulating coating; S2: coating a layer of silicone polymer on the surface of the insulating coating to form an intermediate layer; S3: coating a layer of flame retardant reinforcing material on the surface of the middle layer to form a fire-resistant coating, thereby forming a fire-resistant and insulating inorganic fiber sleeve consisting of the pretreated fiber sleeve, the insulating coating, the middle layer and the fire-resistant coating; The fluorinated modified graphene oxide is prepared by grafting modified graphene oxide with a fluorine-containing compound; The preparation method of the flame retardant reinforced material comprises the following steps: A1: combining a phosphorus-containing compound with hydroxyethyl methacrylate to obtain a flame retardant composite; A2: The flame retardant composite is combined with vinyl-containing silsesquioxane by free radical polymerization to obtain a flame retardant reinforced material.

2. The process for preparing a fire-resistant and insulating inorganic fiber sleeve according to claim 1, characterized in that: In step S1, the method for preparing the pretreated fiber sleeve comprises the following steps: The fiber sleeve is placed in a sodium hydroxide solution, then heated to 90-100°C and maintained for 25-35 minutes, then washed with deionized water, and dried at 80-90°C for 20-30 minutes to obtain an alkalized fiber sleeve, the alkalized fiber sleeve and the ethanol / deionized water solution are mixed, and a silane coupling agent is added, refluxed at 115-125°C for 1-2 hours, and then dried at room temperature to obtain a pretreated fiber sleeve.

3. The process for preparing a fire-resistant and insulating inorganic fiber sleeve according to claim 2, characterized in that: The silane coupling agent is composed of 3-(2-aminoethylamino)propylmethyldimethoxysilane and gamma-glycidyloxypropyltrimethoxysilane mixed in a mass ratio of 0.7-0.8:0.3-0.

4.

4. The process for preparing a fire-resistant and insulating inorganic fiber sleeve according to claim 1, characterized in that: In step S1, the method for preparing fluorinated modified graphene oxide comprises the following steps: The graphene oxide is dispersed in N, N-dimethylformamide and ultrasonically treated for 25-35 minutes, and then trimethylamine is added, and then heated to 105-115°C under a nitrogen atmosphere and maintained for 25-35 minutes, and the fluorine-containing compound dissolved in N, N-dimethylformamide is continued to be added, and the reaction is carried out for 5.5-6.5 hours. After filtering, it is washed with N, N-dimethylformamide, tetrahydrofuran and ethanol in turn, and finally vacuum dried at 55-65°C to obtain fluorinated modified graphene oxide.

5. The process for preparing a fire-resistant and insulating inorganic fiber sleeve according to claim 4, characterized in that: The fluorine-containing compound is composed of hexafluoro-1,10-decanediol and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl mixed in a mass ratio of 0.6-0.7:0.2-0.

4.

6. The process for preparing a fire-resistant and insulating inorganic fiber sleeve according to claim 1, characterized in that: In step S2, the method for preparing the silicon polymer comprises the following steps: Sodium hydroxide is added to deionized water and stirred until completely dissolved, silicon dioxide is added and stirred for 2.5-3.5 hours, hydrochloric acid solution, tetrahydrofuran and sodium chloride are added, and the stirring reaction is continued for 25-35 minutes, and then centrifuged for 10-15 minutes, anhydrous magnesium sulfate is added for dehydration, and the tetrahydrofuran is removed by filtering and rotary evaporation to obtain a silicon polymer.

7. The process for preparing a fire-resistant and insulating inorganic fiber sleeve according to claim 1, characterized in that: Step A1 is specifically as follows: Dichloromethane, hydroxyethyl methacrylate and triethylamine are mixed and placed in an ice water bath, and then a phosphorus-containing compound is added. The mixture is stirred and reacted at room temperature for 4-5 hours. After the reaction is completed, the mixture is washed with a dilute hydrochloric acid aqueous solution and a saturated sodium bicarbonate solution in sequence, and dehydrated with anhydrous magnesium sulfate. Dichloromethane is removed by rotary evaporation, and finally vacuum dried at 55-65°C for 9-11 hours to obtain a flame retardant composite.

8. The process for preparing a fire-resistant and insulating inorganic fiber sleeve according to claim 7, characterized in that: The phosphorus-containing compound is composed of diphenylphosphinyl chloride and 2-carboxyethylphenylphosphinyl chloride mixed in a mass ratio of 0.8-1:0.4-0.

5.

9. The process for preparing a fire-resistant and insulating inorganic fiber sleeve according to claim 1, characterized in that: Step A2 is specifically as follows: Add the flame retardant composite and vinyl silsesquioxane into tetrahydrofuran and mix evenly, then add azobisisobutyronitrile under nitrogen atmosphere, stir and reflux for 7-9 hours, remove tetrahydrofuran by rotary evaporation, add into anhydrous ether, separate the precipitate, and vacuum dry at 55-65°C for 11-13 hours to obtain a flame retardant reinforced material.

10. A fire-resistant insulating inorganic fiber sleeve made by the preparation process according to any one of claims 1 to 9.