Preparation method of silicone rubber cable for explosion-proof motor

Abstract

The invention discloses a preparation method of a silicone rubber cable for an explosion-proof motor, and belongs to the technical field of cables. Wrapping the copper conductor with an inner insulating layer to obtain an insulating wire core; mutually twisting the insulated wire cores to obtain a cable core; the cable core is coated with an outer insulating layer; winding the non-woven fabric outside the insulating layer and filling the filler between the non-woven fabric and the insulating layer; coating the outermost layer with a protective sleeve by adopting an extrusion process; and finally, wrapping the glass fiber tape with a protective sleeve, and weaving a layer of galvanized wires outside the glass fiber tape to obtain the silicone rubber cable. The flame retardant containing nitrogen, phosphorus and fluorine has chemical action with the carbon black and the methyl vinyl silicone rubber, and the three components form a hybrid cross-linked network structure, so that the carbon black and the flame retardant can fully and stably play roles, and the protective jacket is endowed with excellent and stable flame-retardant effect, anti-aging effect, hydrophobic effect and mechanical and physical properties. The protective sleeve and other components of the cable act together, so that the cable is excellent in comprehensive performance and can be used as a cable for an explosion-proof motor.

Description

Technical Field

[0001] The invention belongs to the technical field of cables, and in particular relates to a method for preparing a silicone rubber cable for an explosion-proof motor. Background Art

[0002] With the rapid development of economy, wires and cables are widely used in various industries and fields. With the development of communication, automobile and computer industries, especially aviation wires, automobile wires, high-temperature instrument cables, oil drilling platform cables, explosion-proof motor cables and many other occasions, there is an increasing need to use a silicone rubber insulated cable.

[0003] Silicone rubber is a cross-linkable and curable polymer elastomer with Si-O bond as the main chain and organic groups (such as methyl, vinyl, phenyl, etc.) connected to Si atoms as side chains. Silicone rubber has excellent high and low temperature resistance and can be used for a long time in a wide temperature range (-50℃~200℃). However, silicone rubber itself will continue to burn when encountering open flames, and cables made of it have poor flame retardant properties, which limits its application in various fields of the national economy, especially in occasions with special requirements for flame retardancy and waterproofness, which often need to be modified. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a method for preparing a silicone rubber cable for an explosion-proof motor.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing a silicone rubber cable for an explosion-proof motor comprises the following steps:

[0007] The inner insulating layer is covered on the outside of the copper conductor to obtain an insulated wire core; three insulated wire cores are twisted together to obtain a cable core; an outer insulating layer is covered on the outside of the cable core; a non-woven fabric is wrapped around the outside of the insulating layer and a filler is filled in between to obtain a rough cable; an extrusion process is used to cover the outermost layer of the rough cable with a protective sheath; finally, a glass fiber tape is wrapped around the protective sheath, and a layer of galvanized wire is woven on the outside of the glass fiber tape to prepare a silicone rubber cable for explosion-proof motors.

[0008] Furthermore, the inner insulating layer is one or more of a polypropylene inner insulating layer, a cross-linked polyethylene inner insulating layer and a butyl rubber inner insulating layer.

[0009] Furthermore, the outer insulating layer is one or more of a polyperfluoroethylene propylene outer insulating layer, a polytetrafluoroethylene outer insulating layer, and a polyvinyl chloride outer insulating layer.

[0010] Furthermore, the filler is one or more of glass fiber yarn, aramid yarn, cotton thread, hemp rope and polypropylene rope.

[0011] Furthermore, the protective cover comprises the following raw materials in parts by weight: 100-110 parts of methyl vinyl silicone rubber, 50-60 parts of ethylene-vinyl acetate copolymer, 20-30 parts of styrene-butadiene-styrene block copolymer, 10-20 parts of polyethylene resin, 10-20 parts of carbon black, 5-10 parts of flame retardant, 3-7 parts of lubricant, 3-6 parts of accelerator, 3-4 parts of antioxidant, and 1-4 parts of diisopropylbenzene peroxide.

[0012] Furthermore, the flame retardant is prepared by the following steps:

[0013] S1. Add tri(2-chloroethyl)phosphate, 20wt% sodium hydroxide solution and ethanol to a dry three-necked flask at room temperature, stir to dissolve, then slowly add N-methylallylamine, raise the temperature to 60°C after the addition, keep the temperature for 2h, and after the reaction is completed, distill under reduced pressure, wash with deionized water by centrifugation 3 times, dry, purify by column chromatography (a mixed solvent of cyclohexane and ethyl acetate is selected as the eluent, and the volume ratio of cyclohexane and ethyl acetate is 1:1), and distill under reduced pressure to obtain intermediate 1; the amount ratio of tri(2-chloroethyl)phosphate, N-methylallylamine, 20wt% sodium hydroxide solution and ethanol is 16.4mL:15.5mL:5.8mL:120mL;

[0014] Under alkaline conditions and heating conditions, the -Cl of tri(2-chloroethyl) phosphate and the -NH- of N-methylallylamine undergo a substitution reaction. The reaction process is as follows:

[0015]

[0016] S2. Under nitrogen protection, add intermediate 1, triethylamine and DMSO (dimethyl sulfoxide) into a dry three-necked flask, stir until completely dissolved, then slowly add a mixed solution of melamine and DMSO, place the flask in a 0°C ice-water bath and stir to react for 8 hours, and after the reaction is completed, distill under reduced pressure, purify by column chromatography (the eluent is a mixed solvent of chloroform and ether, and the volume ratio of chloroform and ether is 8:2), and distill under reduced pressure to obtain intermediate 2; the amounts of melamine, intermediate 1, triethylamine and DMSO are 8.8 g: 25.5 g: 12 mL: 130 mL;

[0017] Triethylamine acts as an acid-binding agent, and the -NH2 of melamine and the -Cl of intermediate 1 undergo a nucleophilic substitution reaction. The reaction process is as follows:

[0018]

[0019] S3, under nitrogen protection, 2-(perfluorohexyl) ethyl methacrylate, DBU (1,8-diazobisspiro[5.4.0]undec-7-ene) and DMSO were added to a three-necked flask, stirred evenly, and then the mixed solution of intermediate 2 and DMSO was slowly added. After the addition was completed, the temperature was raised to 60°C and the reaction was carried out for 48 hours. After the reaction was completed, it was distilled under reduced pressure, washed with deionized water for 3 times, dried, purified by column chromatography (the eluent was a mixed solvent of benzene and ether, and the volume ratio of benzene and ether was 6:4), and distilled under reduced pressure to obtain intermediate 3; the usage ratio of intermediate 2, 2-(perfluorohexyl) ethyl methacrylate, DBU and DMSO was 17.8 g:23.5 mL:2.4 mL:120 mL;

[0020] Under the catalytic action of DBU, intermediate 2 undergoes Michael addition reaction with 2-(perfluorohexyl)ethyl methacrylate, and the reaction process is as follows:

[0021]

[0022] S4. Replace the air in the dry three-necked flask with nitrogen at room temperature, then add intermediate 3, pyridine and DMF (N,N-dimethylformamide), stir until completely dissolved, then slowly add 3-chloropropyltriethoxysilane, raise the temperature to 60°C after the addition, stir and react for 2 hours, and distill under reduced pressure after the reaction is completed. Purify by column chromatography (the eluent is a mixed solvent of chloroform and ether, and the volume ratio of chloroform and ether is 8:2), and distill under reduced pressure to obtain a flame retardant. The amount of intermediate 3, 3-chloropropyltriethoxysilane, pyridine and DMF is 13.1g:3.6mL:1.5mL:130mL.

[0023] Pyridine is used as an acid-binding agent, and the -NH- of intermediate 3 and the -Cl of 3-chloropropyltriethoxysilane undergo a nucleophilic substitution reaction. The reaction process is shown below:

[0024]

[0025] The flame retardant containing phosphorus element promotes the carbonization of polymer matrix and forms a molten carbon layer on the surface of polymer matrix, while the flame retardant containing nitrogen element decomposes under heat to generate non-combustible gases such as ammonia and nitrogen, which not only dilute the concentration of oxygen and combustible gas in the flame zone, but also make the molten carbon layer formed on the surface of polymer matrix expand and foam to form a porous foam structure, and the expanded porous foam carbon layer will block the process of heat and oxygen exchange between polymer matrix and the outside world, thereby preventing the polymer material from burning and achieving the final effect of flame retardancy. The flame retardant of the present invention does not contain halogen, will not pollute the environment, and through the synergistic effect of nitrogen and phosphorus, it gives the protective cover an efficient and safe flame retardant effect.

[0026] Flame retardants are rich in fluorine atoms. Adding flame retardants containing multiple fluorine atoms into the protective cover can give the protective cover excellent hydrophobicity and make the protective cover less likely to be contaminated by oil, dust, etc.

[0027] The silane oxygen bonds in the flame retardant can hydrolyze, condense, crosslink, and form covalent bonds with the hydroxyl groups on the surface of carbon black. In addition, the lipophilic carbon chain, heterocycle and ester group on the flame retardant, according to the principle of similar compatibility, both reduce the surface energy of carbon black, and then the carbon black can be evenly dispersed in the protective cover and fully play its role, thereby improving the ultraviolet protection performance, anti-aging performance and mechanical and physical properties of the protective cover, and the flame retardant itself can be evenly dispersed in the protective cover, giving full play to the flame retardant and hydrophobic effects. In addition, the flame retardant also contains a carbon-carbon double bond at the end, which can react chemically with the carbon-carbon double bond in methyl vinyl silicone rubber under the action of diisopropylbenzene peroxide, and then the flame retardant can be grafted on the methyl vinyl silicone rubber macromolecular chain. Therefore, a hybrid cross-linked network structure is formed between carbon black, flame retardant and methyl vinyl silicone rubber. The flame retardant and filler can be dispersed and stably present in the protective cover, and are not easy to migrate and fall out, so that the protective cover has excellent and stable flame retardant effect, anti-aging effect, hydrophobic effect and mechanical and physical properties.

[0028] Furthermore, the lubricant is one or more of calcium stearate, ethylene bis stearamide, zinc stearate, and polyethylene wax.

[0029] Furthermore, the antioxidant is one or more of antioxidant DSTP, antioxidant 1035, antioxidant 1076 and antioxidant 1010.

[0030] Furthermore, the accelerator is one or both of accelerator DM and accelerator CZ.

[0031] The beneficial effects of the present invention are as follows: the flame retardant contains rich halogen-free flame retardant elements nitrogen and phosphorus, which work synergistically to make the flame retardant have efficient and safe flame retardant effects; the flame retardant contains high-density fluorine elements, which makes the flame retardant have super hydrophobicity; there is a chemical reaction between carbon black, flame retardant and methyl vinyl silicone rubber, and the three constitute a hybrid cross-linked network structure, so that carbon black and flame retardant can fully and stably play their roles, giving the protective cover excellent and stable flame retardant effects, anti-aging effects, hydrophobic effects and mechanical and physical properties. The protective cover works together with the other components of the cable, making the cable have excellent comprehensive performance and can be used as a cable for explosion-proof motors. DETAILED DESCRIPTION

[0032] 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.

[0033] Example 1

[0034] The flame retardant is prepared in the following steps:

[0035] S1. Add 16.4 mL of tri(2-chloroethyl)phosphate, 5.8 mL of 20 wt% sodium hydroxide solution and 120 mL of ethanol to a 250 mL dry three-necked flask at room temperature, stir to dissolve, then slowly add 15.5 mL of N-methylallylamine, raise the temperature to 60°C after the addition, and keep the temperature to react for 2 hours. After the reaction is completed, distill under reduced pressure, wash with deionized water by centrifugation 3 times, dry, purify by column chromatography (a mixed solvent of cyclohexane and ethyl acetate is selected as the eluent, and the volume ratio of cyclohexane and ethyl acetate is 1:1), and distill under reduced pressure to obtain intermediate 1;

[0036] S2, under nitrogen protection, add 25.5g of intermediate 1, 12mL of triethylamine and 110mL of DMSO into a 250mL dry three-necked flask, stir until completely dissolved, then slowly add a mixed solution of 8.8g of melamine and 20mL of DMSO, after the addition is complete, place the flask in a 0°C ice water bath and stir to react for 8h, after the reaction is completed, distill under reduced pressure, purify by column chromatography (the eluent is a mixed solvent of chloroform and ether, the volume ratio of chloroform and ether is 8:2), and distill under reduced pressure to obtain intermediate 2;

[0037] S3, under nitrogen protection, 23.5 mL 2-(perfluorohexyl) ethyl methacrylate, 2.4 mL DBU and 100 mL DMSO were added to a 250 mL three-necked flask, stirred evenly, and then 17.8 g of a mixed solution of intermediate 2 and 20 mL DMSO were slowly added. After the addition was completed, the temperature was raised to 60 ° C and reacted for 48 hours. After the reaction was completed, it was distilled under reduced pressure, washed with deionized water 3 times, dried, purified by column chromatography (the eluent was a mixed solvent of benzene and ether, and the volume ratio of benzene and ether was 6:4), and distilled under reduced pressure to obtain intermediate 3;

[0038] S4. Replace the air in a 250 mL dry three-necked flask with nitrogen at room temperature, then add 13.1 g of intermediate 3, 1.5 mL of pyridine and 130 mL of DMF, stir until completely dissolved, then slowly add 3.6 mL of 3-chloropropyltriethoxysilane, raise the temperature to 60 ° C after the addition is complete, stir and react for 2 hours, and distill under reduced pressure after the reaction is completed. Purify by column chromatography (the eluent is a mixed solvent of chloroform and ether, and the volume ratio of chloroform and ether is 8:2), and distill under reduced pressure to obtain a flame retardant.

[0039] Example 2

[0040] The flame retardant is prepared in the following steps:

[0041] The remaining steps remain unchanged, and step S4 of Example 1 is removed to prepare a flame retardant.

[0042] Example 3

[0043] Prepare the protective cover, the specific steps are as follows:

[0044] The raw materials were weighed in parts by weight, and 100 parts of methyl vinyl silicone rubber, 50 parts of ethylene-vinyl acetate copolymer, 20 parts of styrene-butadiene-styrene block copolymer, 10 parts of polyethylene resin, 10 parts of carbon black, 5 parts of the flame retardant prepared in Example 1, 3 parts of calcium stearate, 3 parts of accelerator DM, 3 parts of antioxidant DSTP, and 1 part of diisopropylbenzene peroxide were mixed evenly, and then fed into a twin-screw extruder for melt mixing and extrusion to make a protective sleeve.

[0045] Example 4

[0046] Prepare the protective cover, the specific steps are as follows:

[0047] Weigh each raw material by weight, and mix 105 parts of methyl vinyl silicone rubber, 56 parts of ethylene-vinyl acetate copolymer, 27 parts of styrene-butadiene-styrene block copolymer, 16 parts of polyethylene resin, 18 parts of carbon black, 8 parts of flame retardant prepared in Example 1, 5 parts of ethylene bis stearamide, 5 parts of accelerator CZ, 3.5 parts of antioxidant 1035, and 3 parts of diisopropylbenzene peroxide evenly, then feed into a twin-screw for melt mixing and extrusion to make a protective cover.

[0048] Example 5

[0049] Prepare the protective cover, the specific steps are as follows:

[0050] The raw materials were weighed according to weight, and 110 parts of methyl vinyl silicone rubber, 60 parts of ethylene-vinyl acetate copolymer, 30 parts of styrene-butadiene-styrene block copolymer, 20 parts of polyethylene resin, 20 parts of carbon black, 10 parts of the flame retardant prepared in Example 1, 3 parts of zinc stearate, 4 parts of polyethylene wax, 3 parts of accelerator DM, 3 parts of accelerator CZ, 1 part of antioxidant 1035, 1 part of antioxidant 1076, 2 parts of antioxidant 1010, and 4 parts of diisopropylbenzene peroxide were mixed evenly, and then fed into a twin-screw for melt mixing and extrusion to make a protective cover.

[0051] Example 6

[0052] Preparation of silicone rubber cable for explosion-proof motor, the specific steps are as follows:

[0053] The outer surface of the copper conductor is covered with a polypropylene inner insulation layer to obtain an insulating core; three insulating cores are twisted together to obtain a cable core; a polytetrafluoroethylene propylene outer insulation layer is covered on the outer surface of the cable core; a non-woven fabric is wrapped around the outer surface of the insulating layer and a glass polypropylene rope is filled in between to obtain a rough cable; an extrusion process is then used to cover the outermost layer of the rough cable with the protective sheath obtained in Example 3; finally, a glass fiber tape is wrapped around the protective sheath, and a layer of galvanized wire is woven on the outer surface of the glass fiber tape to prepare a silicone rubber cable for explosion-proof motors.

[0054] Example 7

[0055] Preparation of silicone rubber cable for explosion-proof motor, the specific steps are as follows:

[0056] A butyl rubber inner insulating layer is coated on the outside of a copper conductor to obtain an insulated wire core; three insulated wire cores are twisted together to obtain a cable core; a polyvinyl chloride outer insulating layer is coated on the outside of the cable core; a non-woven fabric is wrapped around the outside of the insulating layer and a hemp rope is filled in between to obtain a rough cable; an extrusion process is then used to coat the outermost layer of the rough cable with the protective sheath obtained in Example 4; finally, a glass fiber tape is wrapped around the protective sheath, and a layer of galvanized wire is woven on the outside of the glass fiber tape to prepare a silicone rubber cable for explosion-proof motors.

[0057] Example 8

[0058] Preparation of silicone rubber cable for explosion-proof motor, the specific steps are as follows:

[0059] The copper conductor is covered with a cross-linked polyethylene inner insulation layer to obtain an insulated wire core; three insulated wire cores are twisted together to obtain a cable core; a polyvinyl chloride outer insulation layer is covered on the cable core; a non-woven fabric is wrapped around the outside of the insulation layer and glass fiber yarns are filled in between to obtain a rough cable; an extrusion process is then used to cover the outermost layer of the rough cable with the protective sheath obtained in Example 5; finally, a glass fiber tape is wrapped around the protective sheath, and a layer of galvanized wire is woven on the outside of the glass fiber tape to prepare a silicone rubber cable for explosion-proof motors.

[0060] Comparative Example 1

[0061] Prepare the protective cover, the specific steps are as follows:

[0062] The remaining steps remain unchanged, and the flame retardant in Example 5 is replaced by 9 parts of the flame retardant in Example 2 and 1 part of 3-chloropropyltriethoxysilane to prepare a protective cover.

[0063] Comparative Example 2

[0064] Prepare the protective cover, the specific steps are as follows:

[0065] The remaining steps remain unchanged, and the flame retardant of Example 5 is added with 5 parts of melamine cyanurate and 5 parts of ammonium polyphosphate to prepare a protective cover.

[0066] Comparative Example 3

[0067] Prepare the protective cover, the specific steps are as follows:

[0068] The remaining steps remain unchanged, and the flame retardant in Example 5 is removed to obtain a protective cover.

[0069] Comparative Example 4

[0070] Prepare silicone rubber cable, the specific steps are as follows:

[0071] The remaining steps remain unchanged, and the protective cover of Example 8 is replaced by the protective cover prepared in Comparative Example 1, thereby preparing a silicone rubber cable.

[0072] Comparative Example 5

[0073] Prepare silicone rubber cable, the specific steps are as follows:

[0074] The remaining steps remain unchanged, and the protective cover of Example 8 is replaced by the protective cover prepared in Comparative Example 2, thereby preparing a silicone rubber cable.

[0075] Comparative Example 6

[0076] Prepare silicone rubber cable, the specific steps are as follows:

[0077] The remaining steps remain unchanged, and the protective cover of Example 8 is replaced by the protective cover prepared in Comparative Example 3, thereby preparing a silicone rubber cable.

[0078] Performance Testing

[0079] The protective covers prepared in Examples 3-5 and Comparative Examples 1-3 were made into corresponding samples according to different standards, and the following performance tests were carried out: the tensile strength and elongation at break were tested according to GB / T1040.3-2006; the vertical burning grade was tested according to GB / T2408-2008; the limiting oxygen index LOI was tested according to GB / T2406.1-2008; the test results of all items are shown in Table 1 below:

[0080] Table 1

[0081]

[0082] From the data comparison of Examples 3-5 and Comparative Examples 1-3, it can be seen that the protective cover prepared by Examples 3-5 of the present invention has excellent mechanical properties, anti-aging properties and flame retardant effects. From the comparison of the test data of Comparative Example 1 and Example 3-5, it can be seen that when the flame retardant preparation step S4 is removed and 3-chloropropyltriethoxysilane is physically mixed in the protective cover, the various properties of the protective cover are reduced. Because the silane coupling agent 3-chloropropyltriethoxysilane physically mixed in the protective cover can improve the dispersion of carbon black, but there is no effect of oil-soluble groups and heterocycles on the flame retardant, the dispersion of carbon black is reduced compared to the dispersion of carbon black in Example 3-5, and carbon black, flame retardant and methyl vinyl silicone rubber cannot form a hybrid cross-linked network structure, which will also cause carbon black and flame retardant to be unable to fully play their own role, therefore, the various properties of the protective cover are reduced.

[0083] With reference to GB / T3048.8-2007 "Test Methods for Electrical Performance of Wires and Cables Part 8: AC Voltage Test", the silicone rubber cables prepared in Examples 6-8 and Comparative Examples 4-6 were subjected to waterproof tests: the cables were bent and placed in a 5% NaCl solution, and AC was continuously applied for 10 hours. The test results are shown in Table 2 below:

[0084] Table 2

[0085]

[0086] The silicone rubber cables prepared in Examples 6-8 and Comparative Examples 4-6 were made into corresponding shapes according to different test standards for performance testing. The test results are shown in Table 3 below:

[0087] Table 3

[0088] project Fire resistance test Smoke density Flame retardant grade Test standards EN 50200 GB / T 8323 IEC 60332 Example 6 pass 49 A Example 7 pass 49 A Example 8 pass 48 A Comparative Example 4 pass 51 A Comparative Example 5 pass 78 B

[0089] From the test results, it can be seen that the silicone rubber cables prepared in Examples 6-8 have excellent flame retardancy, ultra-low smoke density and excellent fire resistance, and can be used as cables for explosion-proof motors.

[0090] 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.

[0091] 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 method for preparing a silicone rubber cable for an explosion-proof motor, characterized in that: The following steps are involved: The method comprises the following steps: covering a copper conductor with an inner insulating layer to obtain an insulating core; twisting three insulating cores together to obtain a cable core; covering the cable core with an outer insulating layer; wrapping a non-woven fabric around the outside of the insulating layer and filling a filler between the layers to obtain a rough cable; and then using an extrusion process to cover the outermost layer of the rough cable with a protective sheath; finally, wrapping a glass fiber tape around the protective sheath and then weaving a layer of galvanized wire around the outside of the glass fiber tape to obtain a silicone rubber cable for explosion-proof motors; The protective cover comprises the following raw materials in parts by weight: 100-110 parts of methyl vinyl silicone rubber, 50-60 parts of ethylene-vinyl acetate copolymer, 20-30 parts of styrene-butadiene-styrene block copolymer, 10-20 parts of polyethylene resin, 10-20 parts of carbon black, 5-10 parts of flame retardant, 3-7 parts of lubricant, 3-6 parts of accelerator, 3-4 parts of antioxidant, and 1-4 parts of diisopropylbenzene peroxide.

2. The method for preparing a silicone rubber cable for explosion-proof motor according to claim 1, characterized in that: The flame retardant is prepared by the following steps: S1. Add tri(2-chloroethyl)phosphate, 20 wt% sodium hydroxide solution and ethanol into a flask at room temperature, stir, add N-methylallylamine, react at 60°C for 2h, distill under reduced pressure, wash, dry, purify by column chromatography, and distill under reduced pressure to obtain intermediate 1; S2, under nitrogen protection, add intermediate 1, triethylamine and DMSO into a flask, stir, add melamine and DMSO, react in an ice-water bath at 0°C for 8 hours, distill under reduced pressure, purify by column chromatography, and distill under reduced pressure to obtain intermediate 2; S3, under nitrogen protection, 2-(perfluorohexyl)ethyl methacrylate, DBU and DMSO were added to a flask, and after stirring, intermediate 2 and DMSO were added, and the mixture was reacted at 60° C. for 48 h, and the mixture was distilled under reduced pressure, washed, dried, purified by column chromatography, and distilled under reduced pressure to obtain intermediate 3; S4. Replace the air in the flask with nitrogen, add intermediate 3, pyridine and DMF, stir, add 3-chloropropyltriethoxysilane, react at 60°C for 2h, distill under reduced pressure, purify by column chromatography, and distill under reduced pressure to obtain a flame retardant.

3. The method for preparing a silicone rubber cable for explosion-proof motor according to claim 2, characterized in that: The amount ratio of tri(2-chloroethyl)phosphate, N-methylallylamine, 20wt% sodium hydroxide solution and ethanol in step S1 is 16.4mL:15.5mL:5.8mL:120mL; the amount of melamine, intermediate 1, triethylamine and DMSO in step S2 is 8.8g:25.5g:12mL:130mL; the amount ratio of intermediate 2, 2-(perfluorohexyl)ethyl methacrylate, DBU and DMSO in step S3 is 17.8g:23.5mL:2.4mL:120mL; the amount of intermediate 3, 3-chloropropyltriethoxysilane, pyridine and DMF in step S4 is 13.1g:3.6mL:1.5mL:130mL.

4. The method for preparing a silicone rubber cable for explosion-proof motor according to claim 1, characterized in that: The inner insulating layer is one or more of a polypropylene inner insulating layer, a cross-linked polyethylene inner insulating layer and a butyl rubber inner insulating layer.

5. The method for preparing a silicone rubber cable for explosion-proof motor according to claim 1, characterized in that: The outer insulating layer is one or more of a polyperfluoroethylene propylene outer insulating layer, a polytetrafluoroethylene outer insulating layer, and a polyvinyl chloride outer insulating layer.

6. The method for preparing a silicone rubber cable for explosion-proof motor according to claim 1, characterized in that: The filler is one or more of glass fiber yarn, aramid yarn, cotton thread, hemp rope and polypropylene rope.

7. The method for preparing a silicone rubber cable for explosion-proof motor according to claim 1, characterized in that: The lubricant is one or more of calcium stearate, ethylene bis stearamide, zinc stearate and polyethylene wax.

8. The method for preparing a silicone rubber cable for explosion-proof motor according to claim 1, characterized in that: The antioxidant is one or more of antioxidant DSTP, antioxidant 1035, antioxidant 1076 and antioxidant 1010.

9. The method for preparing a silicone rubber cable for explosion-proof motor according to claim 1, characterized in that: The accelerator is one or both of accelerator DM and accelerator CZ.

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