A refractory and insulating inorganic fiber sleeve

Abstract

The present invention relates to a fire-resistant and insulating inorganic fiber sleeve, belonging to the technical field of glass fiber sleeves, and comprises the following steps: dip-coating a surface of a pretreated fiber sleeve with a fluorinated modified graphene oxide to form an insulating coating; coating a surface of the insulating coating with a silicon polymer to form an intermediate layer; coating a surface of the intermediate layer with a flame-retardant reinforcing material to form a fire-resistant coating, thereby forming a fire-resistant and insulating inorganic fiber sleeve composed of the pretreated fiber sleeve, the insulating coating, the intermediate layer and the fire-resistant coating; in the technical solution of the present invention, a flame-retardant composite is obtained by combining a phosphorus-containing compound with 2-hydroxyethyl methacrylate; the flame-retardant composite is combined with vinyl silsesquioxane to obtain a flame-retardant reinforcing material; the graphene oxide is graft-modified by a fluorine-containing compound to prepare the fluorinated modified graphene oxide, generally improving the fire resistance, insulation performance, thermal stability and mechanical properties of the inorganic fiber sleeve, and having good comprehensive performance.

Description

Technical Field

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

[0002] A fiber sleeve is a sleeve made of glass fiber reinforced weaving. In wires and some other important electronic components, it is mainly sleeved outside the components, and has the function of protecting the internal components and preventing important components from being damaged. The fiber sleeve itself has good electrical insulation, corrosion resistance, anti-aging property, heat dissipation property, etc. At the same time, it also has excellent flexibility and elasticity, and can maintain softness and bend resistance at low temperatures without reducing its electrical insulation property. Therefore, the fiber sleeve is widely used in various fields such as electrical insulation materials, thermal insulation materials, aerospace, and power equipment.

[0003] During the use of existing fiber sleeves in some high-voltage, high-temperature or special environments, there are still defects such as poor fire resistance and insulation performance. It is easy to cause potential safety hazards inside the circuit due to insufficient performance, causing certain damage to the electronic components in normal operation, seriously affecting the use safety and service life of the fiber sleeve; currently, most of them 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 performance, mechanical performance and thermal stability. Summary of the Invention

[0004] The object of the present invention is to provide a fireproof and insulating inorganic fiber sleeve. By combining a phosphorus-containing compound with 2-hydroxyethyl methacrylate, a flame retardant composite is obtained; the phosphorus-containing compound not only has good flame retardant properties, but also can be well combined with 2-hydroxyethyl methacrylate, and at the same time can provide reaction sites for subsequent reactions; the flame retardant composite is combined with vinyl silsesquioxane through free radical polymerization to obtain a flame retardant reinforced material; the combination of the flame retardant composite and vinyl silsesquioxane not only has good binding force, but also the two can play a synergistic flame retardant role, improving the fire resistance, thermal stability and mechanical properties of the inorganic fiber sleeve; fluorinated modified graphene oxide is prepared by grafting modification of graphene oxide with a fluorine-containing compound; the fluorine-containing compound can improve the dispersibility of graphene oxide, increase its hydrophobic property and thermal stability, and graphene oxide has good insulation properties, which can improve the mechanical properties, thermal stability and insulation properties of the inorganic fiber sleeve; a layer of fluorinated modified graphene oxide is dip-coated on the surface of the pretreated fiber sleeve to form an insulating coating; a layer of silicon polymer is coated on the surface of the insulating coating to form an intermediate layer; a layer of flame retardant reinforced material is dip-coated on the surface of the intermediate layer to form a fireproof coating, thereby forming a fireproof and insulating inorganic fiber sleeve composed of a pretreated fiber sleeve, an insulating coating, an intermediate layer and a fireproof coating; the prepared inorganic fiber sleeve has good fire resistance, insulation properties, thermal stability and mechanical properties, and the comprehensive performance is good.

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

[0006] The object of the present invention can be achieved by the following technical solutions:

[0007] A preparation process of a fireproof and insulating inorganic fiber sleeve, comprising the following steps:

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

[0009] S2: A layer of silicon polymer is coated on the surface of the insulating coating to form an intermediate layer;

[0010] S3: Coat a layer of flame-retardant reinforcing material on the surface of the intermediate layer to form a refractory coating, thereby forming a refractory and insulating inorganic fiber sleeve composed of a pretreated fiber sleeve, an insulating coating, an intermediate layer, and a refractory coating;

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

[0012] The preparation method of the flame-retardant reinforcing material includes the following steps:

[0013] A1: Combine a phosphorus-containing compound with 2-hydroxyethyl methacrylate to obtain a flame-retardant composite;

[0014] A2: Combine the flame-retardant composite with vinylsilsesquioxane through free radical polymerization to obtain a flame-retardant reinforcing material.

[0015] Further, in step S1, the preparation method of the pretreated fiber sleeve includes the following steps:

[0016] Put the fiber sleeve into a sodium hydroxide solution, then heat it to 90 - 100 °C and keep it for 25 - 35 min, then wash it with deionized water and dry it at 80 - 90 °C for 20 - 30 min to obtain an alkalized fiber sleeve. Mix the alkalized fiber sleeve with an ethanol / deionized water solution, then add a silane coupling agent, reflux at 115 - 125 °C for 1 - 2 h, and then dry it at room temperature to obtain a pretreated fiber sleeve.

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

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

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

[0020] Further, the preparation method of the fiber sleeve includes the following steps:

[0021] Weave a basalt fiber sleeve blank from basalt fibers, then round it through a tube-rounding machine, and then pass it through a high-temperature dewaxing furnace to dewax and shape it at 500 - 550 °C for 40 - 60 min to obtain a fiber sleeve.

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

[0023] Further, in step S1, the preparation method of the fluorinated modified graphene oxide includes the following steps:

[0024] Disperse graphene oxide in N,N-dimethylformamide, and ultrasonically treat for 25-35 min. Then add trimethylamine, and then heat to 105-115 °C under a nitrogen atmosphere and maintain for 25-35 min. Continue to add the fluorine-containing compound dissolved in N,N-dimethylformamide and react for 5.5-6.5 h. After filtration, wash successively with N,N-dimethylformamide, tetrahydrofuran and ethanol, and finally vacuum dry at 55-65 °C to obtain fluorinated modified graphene oxide.

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

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

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

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

[0029] Add the fluorinated modified graphene oxide to acetonitrile, and ultrasonically treat for 1-1.5 h. Then add the pretreated fiber sleeve and soak at room temperature for 11-13 h. After filtration, wash successively with acetonitrile, ethanol and deionized water, and finally dry at 80-90 °C for 10-12 h to form an insulating coating.

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

[0031] Further, in step S2, the preparation method of the silicone polymer includes the following steps:

[0032] Add sodium hydroxide to deionized water and stir until completely dissolved. Add silicon dioxide and stir for 2.5 - 3.5 h. Then add hydrochloric acid solution, tetrahydrofuran and sodium chloride, and continue to stir and react for 25 - 35 min. Then centrifuge for 10 - 15 min, add anhydrous magnesium sulfate for dehydration, filter, and remove tetrahydrofuran by 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] Dissolve the silicon polymer in tetrahydrofuran to obtain a silicon solution. Coat the silicon solution on the surface of the insulating coating formed in step S1, then heat at 40 - 50 °C for 15 - 25 min, heat at 90 - 100 °C for 5 - 10 min, and finally dry at 140 - 150 °C for 8 - 12 min to form an intermediate layer.

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

[0037] Furthermore, the coating thickness is 20 - 30 μm.

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

[0039] Mix dichloromethane, 2 - hydroxyethyl methacrylate and triethylamine, and place them in an ice - water bath. Then add a phosphorus - containing compound and stir and react at room temperature for 4 - 5 h. After the reaction is completed, wash successively with dilute hydrochloric acid aqueous solution and saturated sodium bicarbonate solution, dehydrate with anhydrous magnesium sulfate, remove dichloromethane by rotary evaporation, and finally vacuum - dry at 55 - 65 °C for 9 - 11 h to obtain a flame - retardant composite.

[0040] During the above reaction process, 2 - 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 2 - 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, 2 - hydroxyethyl methacrylate and triethylamine is 140 - 150:5.7 - 5.9:5 - 5.2.

[0042] 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] Dissolve the silicon polymer in tetrahydrofuran to obtain a silicon solution. Coat the silicon solution on the surface of the insulating coating formed in step S1, then heat at 40 - 50 °C for 15 - 25 min, heat at 90 - 100 °C for 5 - 10 min, and finally dry at 140 - 150 °C for 8 - 12 min to form an intermediate layer.

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

[0037] Furthermore, the coating thickness is 20 - 30 μm.

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

[0039] Mix dichloromethane, 2 - hydroxyethyl methacrylate and triethylamine, and place them in an ice - water bath. Then add a phosphorus - containing compound and stir and react at room temperature for 4 - 5 h. After the reaction is completed, wash successively with dilute hydrochloric acid aqueous solution and saturated sodium bicarbonate solution, dehydrate with anhydrous magnesium sulfate, remove dichloromethane by rotary evaporation, and finally vacuum - dry at 55 - 65 °C for 9 - 11 h to obtain a flame - retardant composite.

[0040] During the above reaction process, 2 - 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 2 - 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, 2 - hydroxyethyl methacrylate and triethylamine is 140 - 150:5.7 - 5.9:5 - 5.2.

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

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

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

[0045] During the above reaction process, the flame retardant composite has carbon - carbon double bonds, and vinyl sesquisiloxane also has carbon - carbon double bonds. The carbon - carbon double bonds in the flame retardant composite can combine with the carbon - carbon double bonds in vinyl sesquisiloxane through free - radical polymerization reaction to bind the flame retardant composite and vinyl sesquisiloxane together, obtaining the flame retardant reinforced material.

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

[0047] Further, the preparation method of vinyl sesquisiloxane includes the following steps:

[0048] Mix methacryloxypropyltrimethoxysilane, phenyltrimethoxysilane, and acetone, then heat it to 55 - 65 °C, add an aqueous potassium hydroxide solution, react at 55 - 65 °C and maintain for 24 h. After the reaction is completed, cool it to room temperature, neutralize it with acetic acid, wash it with deionized water, remove acetone by vacuum distillation, and finally obtain vinyl sesquisiloxane.

[0049] Further, the mass ratio of methacryloxypropyltrimethoxysilane, phenyltrimethoxysilane, and acetone is 24 - 25:19 - 20:75 - 85.

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

[0051] Add the flame retardant reinforced material into tetrahydrofuran to obtain an enhanced solution. Coat the enhanced solution on the surface of the intermediate layer formed in step S2, then heat it at 45 - 55 °C for 20 - 30 min, heat it at 95 - 105 °C for 10 - 15 min, and finally dry it at 130 - 140 °C for 10 - 15 min to form a refractory coating, thereby forming a fire - resistant and insulating inorganic fiber sleeve composed of a pretreated fiber sleeve, an insulating coating, an intermediate layer, and a refractory coating.

[0052] Further, the mass ratio of the flame retardant reinforced material and tetrahydrofuran is 1:40 - 50.

[0053] Further, the thickness of the coating is 40 - 50 μm.

[0054] Advantages of the present invention:

[0055] (1) In the technical solution of the present invention, a flame retardant composite is obtained by combining a phosphorus-containing compound with 2-hydroxyethyl methacrylate; the phosphorus-containing compound is composed of diphenylphosphinous chloride and 2-carboxyethylphenylphosphinic acid. Diphenylphosphinous chloride and 2-carboxyethylphenylphosphinic acid not only have good flame retardant properties, but also have functional groups that can be well combined with 2-hydroxyethyl methacrylate, and can also provide reaction sites for subsequent reactions; the flame retardant composite is combined with vinylsilsesquioxane by free radical polymerization to obtain a flame retardant reinforced material; vinylsilsesquioxane 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 its organic peripheral structure can improve the compatibility and reactivity with the polymer. Combining the flame retardant composite with vinylsilsesquioxane not only has good binding force, but also the two can 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 and modifying graphene oxide with a fluorine-containing compound; the fluorine-containing compound is composed of hexadecafluoro-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, prevent its aggregation, but also increase its hydrophobic properties and thermal stability. At the same time, graphene oxide has high mechanical properties, excellent thermal stability and good insulation properties. Combining the fluorine-containing compound with graphene oxide has good binding force, which can further improve the mechanical properties, thermal stability and insulation properties of the inorganic fiber sleeve; a layer of fluorinated modified graphene oxide is dip-coated on the surface of the pretreated fiber sleeve to form an insulating coating; the functional groups in the fluorinated modified graphene oxide have good binding force with the functional groups in the pretreated fiber sleeve, increasing the adhesion between the fluorinated modified graphene oxide and the pretreated fiber sleeve; a layer of silicon polymer is coated on the surface of the insulating coating to form an intermediate layer; the silicon polymer has good adhesion. Coating the silicon polymer between the insulating coating and the fire-resistant coating can increase the adhesion between the two and make their combination more firm; a layer of flame retardant reinforced material is dip-coated on the surface of the intermediate layer to form a fire-resistant coating. The flame retardant reinforced material also has good binding force with the silicon polymer, improving the adhesion between the intermediate layer and the fire-resistant coating.

[0057] (3)In the technical solution of the present invention, a flame retardant reinforcing material is obtained by combining a phosphorus-containing compound with 2-hydroxyethyl methacrylate and then combining with vinyl silsesquioxane; fluorinated modified graphene oxide is prepared by grafting modification of 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, then a layer of silicone polymer is coated to form an intermediate layer, and finally a layer of flame retardant reinforcing material is coated to form a refractory coating, thereby forming a fire-resistant and insulating inorganic fiber sleeve composed of a pretreated fiber sleeve, an insulating coating, an intermediate layer and a refractory coating; the prepared inorganic fiber sleeve has good fire resistance, insulation performance, thermal stability and mechanical properties, extends the service life of the fiber sleeve, and has good overall comprehensive performance. Detailed implementation manners

[0058] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope 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 Nano Materials Technology Co., Ltd.; hexadecafluoro-1,10-decanediol, 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 Macklin Biochemical Technology Co., Ltd.; diphenylphosphinous chloride, CAS No.: 1499-21-4, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.; 2-carboxyethylphenylphosphinic acid, CAS No.: 14657-64-8, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.

[0061] Example 1

[0062] To prepare a fire-resistant and insulating inorganic fiber sleeve, the specific steps are as follows:

[0063] S1: According to the mass ratio of fluorinated modified graphene oxide, acetonitrile, and pretreated fiber sleeve of 1:50:4, add the fluorinated modified graphene oxide to acetonitrile, ultrasonically treat for 1 h, then add the pretreated fiber sleeve, and soak at room temperature for 11 h. After filtration, wash successively with acetonitrile, ethanol, and deionized water (the masses of acetonitrile, ethanol, and deionized water are all 10 times the mass of the fluorinated modified graphene oxide), and finally dry at 80 °C for 10 h to form an insulating coating;

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

[0065] According to the mass ratio of the fiber sleeve to the sodium hydroxide solution being 1:20, put the fiber sleeve into a 0.1 mol / L sodium hydroxide solution, then heat it to 90 °C and keep it for 25 min, and then wash it with deionized water (the mass of deionized water is 80 wt% of the mass of the sodium hydroxide solution), dry it at 80 °C for 20 min to obtain an alkalized fiber sleeve. According to the mass ratio of the alkalized fiber sleeve to the ethanol / deionized water solution being 0.8:40, mix the alkalized fiber sleeve with the ethanol / deionized water solution (the volume ratio of ethanol to deionized water is 9:1), and then add a silane coupling agent (the mass of the silane coupling agent is 3 wt% of the mass of the alkalized fiber sleeve), reflux at 115 °C for 1 h, and then dry it at room temperature for 24 h to obtain a pretreated fiber sleeve. Among them, the silane coupling agent is composed of 3-(2-aminoethylamino)propylmethyldimethoxysilane and γ-glycidoxypropyltrimethoxysilane mixed according to a mass ratio of 0.7:0.3;

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

[0067] Weave basalt fibers into a basalt fiber sleeve blank, then round the tube through a tube-passing machine, and then pass it through a high-temperature dewaxing furnace to dewax and shape it at 500 °C for 60 min to obtain a fiber sleeve;

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

[0069] According to the mass ratio of graphene oxide to N,N-dimethylformamide being 0.8:90, disperse graphene oxide in N,N-dimethylformamide and ultrasonically treat it for 25 min (ultrasonic frequency is 40 kHz, ultrasonic power is 100 W), then add trimethylamine (the mass of trimethylamine is 3 wt% of the mass of N,N-dimethylformamide), then heat it to 105 °C under a nitrogen atmosphere and keep it for 25 min. Continue to add a fluorine-containing compound dissolved in N,N-dimethylformamide (the mass of the fluorine-containing compound is 10 wt% of the mass of graphene oxide, and the mass of N,N-dimethylformamide is 50 times the mass of graphene oxide), and react for 5.5 h. After filtration, wash it successively with N,N-dimethylformamide, tetrahydrofuran and ethanol (the masses of N,N-dimethylformamide, tetrahydrofuran and ethanol are all 15 times the mass of graphene oxide), and finally vacuum dry it at 55 °C for 24 h to obtain fluorinated modified graphene oxide. Among them, the fluorine-containing compound is composed of 1H,1H,2H,2H-perfluorodecane-1,10-diol and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl mixed according to a mass ratio of 0.6:0.2;

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

[0071] Among them, the preparation method of the silicon polymer includes the following steps:

[0072] Add sodium hydroxide to deionized water 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, and stir until completely dissolved. Add silicon dioxide and stir for 2.5 h. Then add 2 mol / L hydrochloric acid solution, tetrahydrofuran, and sodium chloride, and continue to stir and react for 25 min. Then centrifuge at a speed of 1000 rpm for 15 min, collect the supernatant, add anhydrous magnesium sulfate for dehydration, filter, and remove tetrahydrofuran by rotary evaporation to obtain the silicon polymer;

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

[0074] The preparation of the flame retardant reinforcing material has the following specific steps:

[0075] A1: Mix dichloromethane, 2-hydroxyethyl methacrylate, and triethylamine according to the mass ratio of 140:5.7:5, place them in an ice-water bath, then add a phosphorus-containing compound (the mass of the phosphorus-containing compound is 2.3 times the mass of 2-hydroxyethyl methacrylate), stir and react at room temperature for 4 h. After the reaction is completed, wash it successively with 8% dilute hydrochloric acid aqueous solution and 10% saturated sodium bicarbonate solution (the masses of the dilute hydrochloric acid aqueous solution and the saturated sodium bicarbonate solution are both 3 times the mass of triethylamine), dehydrate with anhydrous magnesium sulfate, remove dichloromethane by rotary evaporation, and finally vacuum dry at 55 °C for 9 h to obtain a flame retardant composite. Among them, the phosphorus-containing compound is composed of diphenylphosphinic chloride and 2-carboxyethylphenylphosphinic acid mixed according to the mass ratio of 0.8:0.4;

[0076] A2: According to the mass ratio of the flame retardant composite, vinyl sesquisiloxane, and tetrahydrofuran being 6:1.8:240, add the flame retardant composite and vinyl sesquisiloxane into tetrahydrofuran, and mix evenly. Then, under a nitrogen atmosphere, add azobisisobutyronitrile (the mass of azobisisobutyronitrile is 0.7 wt% of the mass of the flame retardant composite), and stir and reflux for 7 h. Remove tetrahydrofuran by rotary evaporation, and then add it to anhydrous ether (the mass of anhydrous ether is 10 wt% of the mass of tetrahydrofuran). After separating the precipitate, dry it under vacuum at 55 °C for 11 h to obtain the flame retardant reinforced material;

[0077] Among them, the preparation method of vinyl sesquisiloxane includes the following steps:

[0078] According to the mass ratio of 3-(methacryloyloxy)propyltrimethoxysilane, phenyltrimethoxysilane, and acetone being 24:19:75, mix 3-(methacryloyloxy)propyltrimethoxysilane, phenyltrimethoxysilane, and acetone, then heat up to 55 °C, add 20 mg / mL potassium hydroxide aqueous solution, react at 55 °C and maintain for 24 h. After the reaction is completed, cool to room temperature, neutralize with acetic acid (the mass of acetic acid is 20 wt% of the mass of acetone), wash 3 times with deionized water (the mass of deionized water each time is 15 wt% of the mass of acetone), remove acetone by vacuum distillation, and finally obtain vinyl sesquisiloxane.

[0079] Example 2

[0080] Prepare a fire-resistant and insulating inorganic fiber sleeve. The specific steps are as follows:

[0081] S1: According to the mass ratio of fluorinated modified graphene oxide, acetonitrile, and the pretreated fiber sleeve being 1.5:55:4.5, add fluorinated modified graphene oxide into acetonitrile, and ultrasonically treat for 1.3 h. Then add the pretreated fiber sleeve and soak at room temperature for 12 h. After filtration, wash successively with acetonitrile, ethanol, and deionized water (the masses of acetonitrile, ethanol, and deionized water are all 10 times the mass of fluorinated modified graphene oxide), and finally dry at 85 °C for 11 h to form an insulating coating;

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

[0083] According to the mass ratio of the fiber sleeve to the sodium hydroxide solution being 1:25, put the fiber sleeve into 0.1 mol / L sodium hydroxide solution, then heat it to 95 °C and keep it for 30 min, and then wash it with deionized water (the mass of deionized water is 80 wt% of the mass of the sodium hydroxide solution), dry it at 85 °C for 25 min to obtain the alkalized fiber sleeve. According to the mass ratio of the alkalized fiber sleeve to the ethanol / deionized water solution being 1:45, mix the alkalized fiber sleeve with the ethanol / deionized water solution (the volume ratio of ethanol to deionized water is 9:1), and then add a silane coupling agent (the mass of the silane coupling agent is 3 wt% of the mass of the alkalized fiber sleeve), reflux at 120 °C for 1.5 h, and then dry it at room temperature for 24 h to obtain the pretreated fiber sleeve. Among them, the silane coupling agent is composed of 3-(2-aminoethylamino)propylmethyldimethoxysilane and γ-glycidoxypropyltrimethoxysilane mixed according to the mass ratio of 0.75:0.35;

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

[0085] Weave the basalt fiber into a basalt fiber sleeve blank, then round the tube through a tube-passing machine, and then pass it through a high-temperature dewaxing furnace to dewax and shape it at 520 °C for 50 min to obtain the fiber sleeve;

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

[0087] According to the mass ratio of graphene oxide to N,N-dimethylformamide being 1:100, disperse the graphene oxide in N,N-dimethylformamide and ultrasonically treat it for 30 min (ultrasonic frequency is 40 kHz, ultrasonic power is 100 W), then add trimethylamine (the mass of trimethylamine is 3 wt% of the mass of N,N-dimethylformamide), then heat it to 110 °C under a nitrogen atmosphere and keep it for 30 min. Continue to add a fluorine-containing compound dissolved in N,N-dimethylformamide (the mass of the fluorine-containing compound is 10 wt% of the mass of graphene oxide, and the mass of N,N-dimethylformamide is 50 times the mass of graphene oxide), and react for 6 h. After filtration, wash it successively with N,N-dimethylformamide, tetrahydrofuran and ethanol (the masses of N,N-dimethylformamide, tetrahydrofuran and ethanol are all 15 times the mass of graphene oxide), and finally vacuum dry it at 60 °C for 24 h to obtain fluorinated modified graphene oxide. Among them, the fluorine-containing compound is composed of hexadecafluoro-1,10-decanediol and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl mixed according to the mass ratio of 0.65:0.3;

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

[0089] Among them, the preparation method of the silicon polymer includes 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, add sodium hydroxide to deionized water and stir until completely dissolved. Add silicon dioxide and stir for 3 h. Then add 2 mol / L hydrochloric acid solution, tetrahydrofuran, and sodium chloride, and continue to stir and react for 30 min. Then centrifuge at a speed of 1500 rpm for 12 min, collect the supernatant, add anhydrous magnesium sulfate for dehydration, filter, and remove tetrahydrofuran by rotary evaporation to obtain the silicon polymer;

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

[0092] The preparation of the flame-retardant reinforcing material is specifically as follows:

[0093] A1: Mix dichloromethane, 2-hydroxyethyl methacrylate, and triethylamine according to the mass ratio of 145:5.8:5.1, place them in an ice-water bath, then add a phosphorus-containing compound (the mass of the phosphorus-containing compound is 2.3 times the mass of 2-hydroxyethyl methacrylate), stir and react at room temperature for 4.5 h. After the reaction is completed, wash successively with 8% dilute hydrochloric acid aqueous solution and 10% saturated sodium bicarbonate solution (the masses of the dilute hydrochloric acid aqueous solution and the saturated sodium bicarbonate solution are both 3 times the mass of triethylamine), dehydrate with anhydrous magnesium sulfate, remove dichloromethane by rotary evaporation, and finally vacuum dry at 60 °C for 10 h to obtain a flame-retardant composite. Among them, the phosphorus-containing compound is composed of diphenylphosphinic chloride and 2-carboxyethylphenylphosphinic acid mixed according to the 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, add the flame retardant composite and vinyl silsesquioxane into tetrahydrofuran, and mix evenly. Then, add azobisisobutyronitrile (the mass of azobisisobutyronitrile is 0.7 wt% of the mass of the flame retardant composite) under a nitrogen atmosphere, and stir and reflux for 8 h. Remove tetrahydrofuran by rotary evaporation, and then add it to anhydrous ether (the mass of anhydrous ether is 10 wt% of the mass of tetrahydrofuran). After separating the precipitate, dry it under vacuum at 60 °C for 12 h to obtain the flame retardant reinforced material;

[0095] Among them, the preparation method of vinyl silsesquioxane includes the following steps:

[0096] According to the mass ratio of 3-(methacryloyloxy)propyltrimethoxysilane, phenyltrimethoxysilane, and acetone being 24.5:19.5:80, mix 3-(methacryloyloxy)propyltrimethoxysilane, phenyltrimethoxysilane, and acetone, then heat up to 60 °C, add 20 mg / mL potassium hydroxide aqueous solution, react at 60 °C and maintain for 24 h. After the reaction is completed, cool to room temperature, neutralize with acetic acid (the mass of acetic acid is 20 wt% of the mass of acetone), wash with deionized water 3 times (the mass of deionized water each time is 15 wt% of the mass of acetone), remove acetone by vacuum distillation, and finally obtain vinyl silsesquioxane.

[0097] Example 3

[0098] Prepare a refractory and insulating inorganic fiber sleeve, and the specific steps are as follows:

[0099] S1: According to the mass ratio of fluorinated modified graphene oxide, acetonitrile, and the pretreated fiber sleeve being 2:60:5, add fluorinated modified graphene oxide into acetonitrile, and ultrasonically treat for 1.5 h. Then, add the pretreated fiber sleeve and soak at room temperature for 13 h. After filtration, wash successively with acetonitrile, ethanol, and deionized water (the masses of acetonitrile, ethanol, and deionized water are all 10 times the mass of fluorinated modified graphene oxide), and finally dry at 90 °C for 12 h to form an insulating coating;

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

[0101] The fiber sleeve was placed in 0.1 mol / L sodium hydroxide solution according to the mass ratio of the fiber sleeve to the sodium hydroxide solution of 1:30, and then heated to 100 °C and maintained for 35 min. It was then washed with deionized water (the mass of deionized water was 80 wt% of the mass of the sodium hydroxide solution) and dried at 90 °C for 30 min 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 was 9:1) were mixed, and a silane coupling agent (the mass of the silane coupling agent was 3 wt% of the mass of the alkalized fiber sleeve) was added. The mixture was refluxed at 125 °C for 2 h and then dried at room temperature for 24 h to obtain a pretreated fiber sleeve. Among them, the silane coupling agent was composed of 3-(2-aminoethylamino)propylmethyldimethoxysilane and γ-glycidoxypropyltrimethoxysilane mixed according to the mass ratio of 0.8:0.4;

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

[0103] The basalt fiber was woven into a basalt fiber sleeve blank, and then the tube was rounded through a tube-passing machine. Then it was passed through a high-temperature dewaxing furnace and dewaxed and shaped at 550 °C for 40 min to obtain the fiber sleeve;

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

[0105] Graphene oxide was dispersed in N,N-dimethylformamide according to the mass ratio of graphene oxide to N,N-dimethylformamide of 1.2:110, and ultrasonic treatment was carried out for 35 min (ultrasonic frequency was 40 kHz, ultrasonic power was 100 W). Trimethylamine (the mass of trimethylamine was 3 wt% of the mass of N,N-dimethylformamide) was added, and then it was heated to 115 °C under a nitrogen atmosphere and maintained for 35 min. 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, and the mass of N,N-dimethylformamide was 50 times the mass of graphene oxide) was continuously added and reacted for 6.5 h. After filtration, it was washed successively with N,N-dimethylformamide, tetrahydrofuran and ethanol (the masses of N,N-dimethylformamide, tetrahydrofuran and ethanol were all 15 times the mass of graphene oxide). Finally, it was vacuum dried at 65 °C for 24 h to obtain fluorinated modified graphene oxide. Among them, the fluorine-containing compound was composed of 1H,1H,2H,2H-hexadecafluorodecanediol and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl mixed according to the mass ratio of 0.7:0.4;

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

[0107] Among them, the preparation method of the silicon polymer includes the following steps:

[0108] Add sodium hydroxide to deionized water 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, and stir until completely dissolved. Add silicon dioxide and stir for 3.5 h. Then add 2 mol / L hydrochloric acid solution, tetrahydrofuran, and sodium chloride, and continue to stir and react for 35 min. Then centrifuge at a speed of 2000 rpm for 10 min, collect the supernatant, add anhydrous magnesium sulfate for dehydration, filter, and remove tetrahydrofuran by rotary evaporation to obtain the silicon polymer;

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

[0110] The preparation of the flame-retardant reinforcing material is specifically carried out as follows:

[0111] A1: Mix dichloromethane, 2-hydroxyethyl methacrylate, and triethylamine according to the mass ratio of 150:5.9:5.2, place them in an ice-water bath, then add a phosphorus-containing compound (the mass of the phosphorus-containing compound is 2.3 times the mass of 2-hydroxyethyl methacrylate), stir and react at room temperature for 5 h. After the reaction is completed, wash successively with 8% dilute hydrochloric acid aqueous solution and 10% saturated sodium bicarbonate solution (the masses of the dilute hydrochloric acid aqueous solution and the saturated sodium bicarbonate solution are both 3 times the mass of triethylamine), dehydrate with anhydrous magnesium sulfate, remove dichloromethane by rotary evaporation, and finally vacuum dry at 65 °C for 11 h to obtain the flame-retardant composite. Among them, the phosphorus-containing compound is composed of diphenylphosphinic chloride and 2-carboxyethylphenylphosphinic acid mixed according to the mass ratio of 1:0.5;

[0112] A2: According to the mass ratio of the flame retardant composite, vinyl silsesquioxane, and tetrahydrofuran being 6.5:2:250, add the flame retardant composite and vinyl silsesquioxane to tetrahydrofuran and mix evenly. Then, add azobisisobutyronitrile (the mass of azobisisobutyronitrile is 0.7 wt% of the mass of the flame retardant composite) under a nitrogen atmosphere and stir and reflux for 9 h. Remove tetrahydrofuran by rotary evaporation, and then add it to anhydrous ether (the mass of anhydrous ether is 10 wt% of the mass of tetrahydrofuran). After separating the precipitate, vacuum dry it at 65 °C for 13 h to obtain the flame retardant reinforced material;

[0113] Among them, the preparation method of vinyl silsesquioxane includes the following steps:

[0114] According to the mass ratio of 3-(methacryloyloxy)propyltrimethoxysilane, phenyltrimethoxysilane, and acetone being 25:20:85, mix 3-(methacryloyloxy)propyltrimethoxysilane, phenyltrimethoxysilane, and acetone, then heat up to 65 °C, add 20 mg / mL potassium hydroxide aqueous solution, react at 65 °C and maintain for 24 h. After the reaction is completed, cool to room temperature, neutralize with acetic acid (the mass of acetic acid is 20 wt% of the mass of acetone), wash with deionized water 3 times (the mass of deionized water each time is 15 wt% of the mass of acetone), remove acetone by vacuum distillation, and finally obtain vinyl silsesquioxane.

[0115] Comparative Example 1

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

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

[0118] According to the mass ratio of the fiber sleeve and sodium hydroxide solution being 1:30, put the fiber sleeve into 0.1 mol / L sodium hydroxide solution, then heat to 100 °C and maintain for 35 min, and then wash with deionized water (the mass of deionized water is 80 wt% of the mass of sodium hydroxide solution), dry at 90 °C for 30 min to obtain the alkalized fiber sleeve. According to the mass ratio of the alkalized fiber sleeve and ethanol / deionized water solution being 1.2:50, mix the alkalized fiber sleeve and ethanol / deionized water solution (the volume ratio of ethanol and deionized water is 9:1), and then add 3-(2-aminoethylamino)propylmethyldimethoxysilane (the mass of 3-(2-aminoethylamino)propylmethyldimethoxysilane is 3 wt% of the mass of the alkalized fiber sleeve), reflux at 125 °C for 2 h, and then dry at room temperature for 24 h to obtain the pretreated fiber sleeve.

[0119] Comparative Example 2

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

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

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

[0123] Comparative Example 3

[0124] The difference between this comparative example and Example 3 is that when preparing the refractory and insulating inorganic fiber sleeve, in step S1, the fluorine-containing compound in the fluorinated modified graphene oxide is replaced with 1H,1H,10H,10H-perfluorodecane-1,10-diol in equal mass, and the remaining steps and raw materials are the same as those in Example 3;

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

[0126] According to the mass ratio of graphene oxide to N,N-dimethylformamide of 1.2:110, the graphene oxide is dispersed in N,N-dimethylformamide and ultrasonicated for 35 min (ultrasonic frequency is 40 kHz, ultrasonic power is 100 W), then trimethylamine is added (the mass of trimethylamine is 3 wt% of the mass of N,N-dimethylformamide), and then heated to 115 °C under a nitrogen atmosphere and kept for 35 min. Then, 1H,1H,10H,10H-perfluorodecane-1,10-diol dissolved in N,N-dimethylformamide is added (the mass of 1H,1H,10H,10H-perfluorodecane-1,10-diol is 10 wt% of the mass of graphene oxide, and the mass of N,N-dimethylformamide is 50 times the mass of graphene oxide), and the reaction is carried out for 6.5 h. After filtration, it is washed successively with N,N-dimethylformamide, tetrahydrofuran and ethanol (the masses of N,N-dimethylformamide, tetrahydrofuran and ethanol are all 15 times the mass of graphene oxide), and finally vacuum dried at 65 °C for 24 h to obtain the fluorinated modified graphene oxide.

[0127] Comparative Example 4

[0128] The difference between this comparative example and Example 3 is that when preparing the refractory and insulating inorganic fiber sleeve, in step S2, the silicone polymer is replaced with silica sol in equal mass, and the remaining steps and raw materials are the same as those in Example 3;

[0129] S2: Coat the surface of the insulating coating formed in step S1 with silica sol, with a coating thickness of 30 μm, then heat it at 50 °C for 25 min, heat it at 100 °C for 10 min, and finally dry it 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 reinforcing material, the phosphorus-containing compound in step A1 is replaced with diphenylphosphinic chloride in equal mass, and the remaining steps and raw materials are the same as those in Example 3;

[0132] A1: According to the mass ratio of dichloromethane, 2-hydroxyethyl methacrylate and triethylamine being 150:5.9:5.2, mix dichloromethane, 2-hydroxyethyl methacrylate and triethylamine, and place them in an ice-water bath. Then add diphenylphosphinic chloride (the mass of diphenylphosphinic chloride is 2.3 times the mass of 2-hydroxyethyl methacrylate), stir and react at room temperature for 5 h. After the reaction is completed, wash it successively with 8% dilute hydrochloric acid aqueous solution and 10% saturated sodium bicarbonate solution (the masses of the dilute hydrochloric acid aqueous solution and the saturated sodium bicarbonate solution are both 3 times the mass of triethylamine), dehydrate with anhydrous magnesium sulfate, remove dichloromethane by rotary evaporation, and finally vacuum dry at 65 °C for 11 h 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 reinforcing material, the vinylsilsesquioxane in step A2 is replaced with octaisobutylcage polyhedral oligomeric silsesquioxane in equal mass, 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, octaisobutylcage polyhedral oligomeric silsesquioxane, and tetrahydrofuran being 6.5:2:250, add the flame-retardant composite and octaisobutylcage polyhedral oligomeric silsesquioxane to tetrahydrofuran and mix evenly. Then add azobisisobutyronitrile (the mass of azobisisobutyronitrile is 0.7 wt% of the mass of the flame-retardant composite) under a nitrogen atmosphere and stir and reflux for 9 h. Remove tetrahydrofuran by rotary evaporation, and then add it to anhydrous ether (the mass of anhydrous ether is 10 wt% of the mass of tetrahydrofuran). After separating the precipitate, vacuum dry at 65 °C for 13 h to obtain the flame-retardant reinforcing material.

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

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

[0138] Project Flame retardant grade <![CDATA[Breakdown voltage ( kV )]]> Strength at low temperature (-10°C) Example 1 V-0 9.8 Hard, the curved surface does not break Example 2 V-0 9.9 Hard, the curved surface does not break Example 3 V-0 9.7 Hard, the curved surface does not break Comparative example 1 V-1 9.5 Brittle, the curved surface is slightly broken Comparative example 2 V-1 9.1 Brittle, the curved surface breaks Comparative example 3 V-1 9.3 Brittle, the curved surface is slightly broken Comparative example 4 V-1 9.0 Brittle, the curved surface breaks Comparative example 5 V-1 9.3 Brittle, the curved surface is slightly broken Comparative example 6 V-1 9.2 Brittle, the curved surface is slightly broken

[0139] As can be seen from the data in Table 1 above, by comparing Comparative Examples 1-2 and Example 3, it can be seen that when the silane coupling agent in the pretreated fiber sleeve is replaced with 3-(2-aminoethylamino)propylmethyldimethoxysilane in equal mass or the pretreated fiber sleeve is not treated with the silane coupling agent to prepare the fire-resistant and insulating inorganic fiber sleeve, the test results are worse than those of Example 3, indicating that treating the fiber sleeve with the silane coupling agent can effectively graft the silane coupling agent on the surface of the fiber sleeve, enhance the compatibility between the fiber sleeve and the insulating coating, and the silane coupling agent composed of a mixture of 3-(2-aminoethylamino)propylmethyldimethoxysilane and γ-glycidoxypropyltrimethoxysilane 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 has a good influence on its fire resistance and insulation performance;

[0140] It can be seen from the comparison between Comparative Example 3 and Example 3 that when the fluorine-containing compound in the fluorinated modified graphene oxide is replaced with 1H,1H,2H,2H-hexadecafluoro-1,10-decanediol in equal mass, and finally a fire-resistant and insulating inorganic fiber sleeve is prepared, the test results are worse than those of Example 3. This shows that the fluorine-containing compound composed of 1H,1H,2H,2H-hexadecafluoro-1,10-decanediol and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl has more fluorine atoms and better hydrophobic performance. It can not only combine well with graphene oxide to increase the dispersibility of graphene oxide, but also can improve the interfacial 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 performance of the fiber sleeve;

[0141] It can be seen from the comparison between Comparative Example 4 and Example 3 that when the silicone polymer is replaced with silica sol in equal mass to prepare a fire-resistant and insulating inorganic fiber sleeve, the test results are worse than those of Example 3. This shows that the silicone polymer has good adhesion. Coating the silicone polymer in the middle of the insulating coating and the fire-resistant coating to form an intermediate layer can better improve the adhesion performance between the insulating coating and the fire-resistant coating, and further improve the fire resistance, insulation performance and mechanical properties of the inorganic fiber sleeve;

[0142] It can be seen from the comparison between Comparative Examples 5-6 and Example 3 that when the phosphorus-containing compound in Step A1 is replaced with diphenylphosphinic chloride or the vinyl-containing silsesquioxane in Step A2 is replaced with octaisobutyl silsesquioxane in equal mass to prepare a fire-resistant and insulating inorganic fiber sleeve, the test results are worse than those of Example 3. This shows that the phosphorus-containing compound composed of diphenylphosphinic chloride and 2-carboxyethylphenylphosphinic acid has good flame retardant performance. Combining the phosphorus-containing compound with 2-hydroxyethyl methacrylate can also provide reaction sites for subsequent reactions. Combining the flame retardant composite with the vinyl-containing silsesquioxane not only has good bonding force, but also has a synergistic flame retardant effect between the vinyl-containing silsesquioxane and the phosphorus-containing compound, which can better improve the fire resistance, insulation performance and mechanical properties of the inorganic fiber sleeve.

[0143] As can be seen from Table 1 above, compared with the fire-resistant and insulating inorganic fiber sleeves prepared in Comparative Examples 1-6, the fire-resistant and insulating inorganic fiber sleeves prepared in Examples 1-3 are obtained by combining a phosphorus-containing compound with 2-hydroxyethyl methacrylate and then combining with vinyl silsesquioxane to obtain a flame-retardant reinforcing material; fluorinated modified graphene oxide is prepared by grafting modification of graphene oxide with a fluorine-containing compound; a layer of fluorinated modified graphene oxide is dip-coated on the surface of the pretreated fiber sleeve to form an insulating coating, 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 composed of a pretreated fiber sleeve, an insulating coating, an intermediate layer and a fire-resistant coating, meeting the requirements of the test performance. However, the fire-resistant and insulating inorganic fiber sleeves prepared in Comparative Examples 1-6 do not meet the standard of the performance requirements, indicating that the fire-resistant and insulating inorganic fiber sleeve prepared by the present invention has good mechanical properties, fire resistance, insulation properties and thermal stability, extends the service life of the fiber sleeve, and has good comprehensive performance.

[0144] In the description of the specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection 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 a suitable manner in any one or more embodiments or examples.

[0145] The above content is only an example and illustration of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, they should fall within the protection scope of the present invention.

Claims

1. A preparation process of a refractory and insulating inorganic fiber sleeve, characterized in that, It includes the following steps: S1: Dip - coat a layer of fluorinated modified graphene oxide on the surface of the pretreated fiber sleeve to form an insulating coating; S2: Coat a layer of silicon polymer on the surface of the insulating coating to form an intermediate layer; S3: Coat a layer of flame - retardant reinforcing material on the surface of the intermediate layer to form a fire - resistant coating, thereby forming a fire - resistant and insulating inorganic fiber sleeve composed of the pretreated fiber sleeve, insulating coating, intermediate layer and fire - resistant coating; The fluorinated modified graphene oxide is prepared by graft - modifying graphene oxide with a fluorine - containing compound; The preparation method of the flame - retardant reinforcing material includes the following steps: A1: Combine a phosphorus - containing compound with 2 - hydroxyethyl methacrylate to obtain a flame - retardant composite; A2: Combine the flame - retardant composite with vinyl - containing sesquisiloxane through free - radical polymerization to obtain a flame - retardant reinforcing material; The fluorine - containing compound is composed of 1H,1H,2H,2H - hexadecafluoro - 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; The preparation method of the silicon polymer includes the following steps: Add sodium hydroxide to deionized water and stir until completely dissolved. Add silicon dioxide and stir for 2.5 - 3.5 h. Then add hydrochloric acid solution, tetrahydrofuran and sodium chloride, and continue to stir and react for 25 - 35 min. Then centrifuge for 10 - 15 min, add anhydrous magnesium sulfate for dehydration, filter, and remove tetrahydrofuran by rotary evaporation to obtain the silicon polymer; The phosphorus - containing compound is composed of diphenylphosphinous chloride and 2 - carboxyethylphenylphosphinic acid mixed in a mass ratio of 0.8 - 1:0.4 - 0.5; The preparation method of the pretreated fiber sleeve includes the following steps: Put the fiber sleeve into a sodium hydroxide solution, then heat to 90 - 100 °C and keep for 25 - 35 min. Then wash with deionized water and dry at 80 - 90 °C for 20 - 30 min to obtain an alkalized fiber sleeve. Mix the alkalized fiber sleeve with an ethanol / deionized water solution, then add a silane coupling agent, reflux at 115 - 125 °C for 1 - 2 h, and then dry at room temperature to obtain the pretreated fiber sleeve; The silane coupling agent is composed of 3-(2 - aminoethylamino)propylmethyldimethoxysilane and γ - glycidoxypropyltrimethoxysilane mixed in a mass ratio of 0.7 - 0.8:0.3 - 0.

4.

2. The preparation process of a refractory and insulating inorganic fiber sleeve according to claim 1, characterized in that, In step S1, the preparation method of the fluorinated modified graphene oxide includes the following steps: Disperse graphene oxide in N,N - dimethylformamide and ultrasonically treat for 25 - 35 min. Then add trimethylamine, and then heat to 105 - 115 °C under a nitrogen atmosphere and keep for 25 - 35 min. Continue to add the fluorine - containing compound dissolved in N,N - dimethylformamide and react for 5.5 - 6.5 h. After filtration, wash successively with N,N - dimethylformamide, tetrahydrofuran and ethanol, and finally vacuum - dry at 55 - 65 °C to obtain the fluorinated modified graphene oxide.

3. The preparation process of a fireproof and insulating inorganic fiber sleeve according to claim 1, characterized in that, Step A1 is specifically: Mix dichloromethane, 2-hydroxyethyl methacrylate and triethylamine, and place them in an ice-water bath. Then add the phosphorus-containing compound, and stir the reaction at room temperature for 4-5 h. After the reaction is completed, wash successively with dilute hydrochloric acid aqueous solution and saturated sodium bicarbonate solution, dehydrate with anhydrous magnesium sulfate, remove dichloromethane by rotary evaporation, and finally vacuum dry at 55-65 °C for 9-11 h to obtain the flame retardant composite.

4. The preparation process of a refractory 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 to tetrahydrofuran and mix evenly. Then add azobisisobutyronitrile under a nitrogen atmosphere and stir and reflux for 7-9 h. Remove tetrahydrofuran by rotary evaporation, add it to anhydrous ether, separate the precipitate, and vacuum dry at 55-65 °C for 11-13 h to obtain the flame retardant reinforced material.

5. A fireproof and insulating inorganic fiber sleeve produced by the preparation process according to any one of claims 1-4.