Ceramic low-smoke halogen-free cable for coal mine
The ceramic low-smoke halogen-free coal mine cable addresses poor mechanical and flame retardant properties by using cross-linked polyethylene, acrylic copolymer, modified lignin, and composite ceramic powder, achieving enhanced mechanical strength and flame retardancy through a specialized preparation process.
Patent Information
- Application Number
- CN202411215694.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-02
- Publication Date
- 2024-12-06
AI Technical Summary
Existing coal mine power cables face challenges with poor mechanical properties and poor flame retardancy, particularly in maintaining high strength and halogen-free characteristics while ensuring excellent flame retardant properties.
A ceramic low-smoke halogen-free coal mine cable is prepared using cross-linked polyethylene and acrylic acid copolymer as organic substrates, modified lignin and composite ceramic powder as functional additives, with antioxidants and stabilizers, and a specific preparation method involving silane coupling agents and nucleophilic reactions to enhance mechanical and flame retardant properties.
The cable achieves improved mechanical strength and halogen-free flame retardancy, forming a dense protective carbon layer and enhancing compatibility between ceramic and organic components, resulting in high tensile strength and excellent flame retardant performance.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of electric wires and cables, and in particular to a ceramic low-smoke and halogen-free cable for coal mines. Background Art
[0002] Wires and cables are electrical wire products used to transmit electrical energy, transfer information and realize electromagnetic. Wires and cables include conductive cores, insulation layers, protective layers, etc. The conductive cores are required to have high electrical conductivity, sufficient mechanical strength and chemical stability, and be easy to process and weld; the insulation layer is required to have excellent electrical insulation properties; the protective layer is to protect and prevent the insulating material from various external factors to ensure the use of wires and cables. Cable sheaths are the first layer of protection for cables against external damage. The quality of their performance is related to a series of issues such as power transmission and electricity safety. The cable materials used in coal mines must have good mechanical properties and flame retardancy to avoid explosions.
[0003] In addition, with the increasing awareness of environmental protection, wires and cables made of halogen-free flame-retardant materials have gradually become the first choice for various industries; polyethylene and cross-linked polyethylene have gradually replaced fluoroplastics and polyvinyl chloride and become the first choice for preparing power cable materials. However, polyethylene is flammable and has poor compatibility with inorganic materials. How to maintain the high strength and halogen-free characteristics of power cables while still having excellent flame retardant properties is a technical problem that needs to be solved urgently.
[0004] In view of the technical defects in this aspect, a solution is now proposed. Summary of the invention
[0005] The object of the present invention is to provide a ceramic low-smoke halogen-free coal mine cable, which is used to solve the technical problems of poor mechanical properties and poor flame retardancy of coal mine power cables in the prior art.
[0006] The purpose of the present invention can be achieved by the following technical solutions:
[0007] A ceramic low-smoke halogen-free coal mine cable comprises the following components in parts by weight: 50-60 parts of dried cross-linked polyethylene, 30-40 parts of dried acrylic copolymer, 10-20 parts of modified lignin, 10-20 parts of composite ceramic powder, 2-4 parts of antioxidant, 2-4 parts of stabilizer and 3-5 parts of plasticizer.
[0008] The cable prepared by the invention uses cross-linked polyethylene and acrylic acid copolymer as organic substrates, modified lignin and composite ceramic powder as functional additives, and is further doped with antioxidants, stabilizers and plasticizers, thereby preparing a ceramic low-smoke halogen-free coal mine cable.
[0009] Furthermore, the preparation method of the composite flame retardant comprises the following steps:
[0010] S1, γ-(diethylenetriamine)propyltriethoxysilane and water are mixed and reacted to obtain a silanol liquid; lignin is then added to the silanol liquid, the temperature is raised to 70-80° C., and the reaction is performed for 2-3 hours to obtain a mixed solid-liquid; the mixed solid-liquid is filtered to obtain a solid; the solid is washed with deionized water and vacuum dried to obtain a modified lignin;
[0011] γ-(diethylenetriamine)propyltriethoxysilane is hydrolyzed to obtain silanol, and the surface of lignin contains hydroxyl groups. The silanol and the hydroxyl groups on the surface of lignin undergo a dehydration reaction under heating conditions to prepare modified lignin.
[0012] The reaction formula for preparing modified lignin by dehydration condensation of silanol and lignin is as follows:
[0013]
[0014] S2, cyanuric chloride, anhydrous sodium carbonate and 1,4-dioxane are mixed and stirred to obtain a reaction mixture; then modified lignin is added to the reaction mixture, reacted at 0-20°C for 2-3h, then reacted at 50°C for 2-3h, and finally reacted at 100°C for 2-3h to obtain a product; the product is filtered and vacuum dried to obtain a composite flame retardant.
[0015] With anhydrous sodium carbonate as a catalyst and 1,4-dioxane as a solvent, cyanuric chloride and modified lignin undergo nucleophilic reaction to prepare a composite flame retardant.
[0016] The reaction formula for preparing the composite flame retardant by reacting cyanuric chloride with modified lignin is as follows:
[0017]
[0018] Furthermore, in step S1, the usage ratio of γ-(diethylenetriamine)propyltriethoxysilane and water is 25-35 g:100 mL, and the vacuum drying temperature is 70-80°C.
[0019] Furthermore, in step S2, the usage ratio of cyanuric chloride, anhydrous sodium carbonate and 1,4-dioxane is 45-55 g:100 g:500 mL, and the vacuum drying temperature is 70-80°C.
[0020] Furthermore, the method for preparing the composite ceramic powder comprises the following steps:
[0021] A1. Add silicon nitride ceramics into a planetary ball mill and mill to 100-200 μm to obtain silicon nitride ceramic powder;
[0022] A2, 2-allyl oxirane, trimethoxysilane and a platinum catalyst are mixed and reacted at 55-75° C. for 30-40 minutes to obtain an organic liquid; the organic liquid is filtered to remove the platinum catalyst, and the organic liquid is subjected to reduced pressure distillation to obtain a modified silane coupling agent;
[0023] 2-allyl oxirane and trimethoxysilane undergo a hydrosilylation reaction to prepare a modified silane coupling agent.
[0024] The reaction formula of 2-allyl oxirane and trimethoxysilane is as follows:
[0025]
[0026] A3. Mix and stir silicon nitride ceramic powder and modified silane coupling agent to obtain modified silicon nitride ceramic powder.
[0027] Silicon nitride ceramic powder is used as a reinforcing material for preparing cables. It is modified by using a modified silane coupling agent to prepare modified silicon nitride ceramic powder.
[0028] Furthermore, in step A2, the amount ratio of 2-allyl oxirane, trimethoxysilane and platinum catalyst is 20-30g:20-25g:1-2g; the temperature of vacuum distillation is 50-60°C, and the pressure of vacuum distillation is 300-400MPa; in step A3, the amount ratio of silicon nitride ceramic powder and modified silane coupling agent is 200-300g:20-30g.
[0029] Furthermore, the preparation method of the ceramic low-smoke halogen-free coal mine cable comprises the following steps:
[0030] B1. Dry the cross-linked polyethylene and the acrylic acid copolymer at 50° C. for 10-12 hours in sequence to obtain dried cross-linked polyethylene and dried acrylic acid copolymer, respectively; mix the dried cross-linked polyethylene, the dried acrylic acid copolymer, the modified lignin and the composite ceramic powder to obtain a mixture; then add an antioxidant, a stabilizer and a plasticizer to the mixture, mix again to obtain a raw material;
[0031] B2. Add the raw materials into a torque rheometer, and perform melt blending at 190-200° C. to obtain a cable material; then add the cable material into a flat vulcanizer, and perform vulcanization at 180-190° C. and 15-20 MPa to obtain a ceramic low-smoke halogen-free coal mine cable.
[0032] Furthermore, in step B1, the antioxidant is any one of N-isopropyl-N'-diphenyl-p-phenylenediamine, tris(nonylphenyl)phosphite, triester phosphite, and tris(2,4-di-tert-butyl)phenyl phosphite; the stabilizer is any one of tribasic lead sulfate, dibasic lead sulfate, or dibasic lead phthalate; and the plasticizer is any one of diphenyl octyl phosphate, trioctyl phosphate, tricresyl phosphate, or tributyl phosphate.
[0033] The present invention has the following beneficial effects:
[0034] 1. The cable prepared by the present invention uses cross-linked polyethylene and acrylic acid copolymer as organic substrates, improves the flame retardant properties of the cable material by adding modified lignin, and improves the mechanical properties of the cable material by adding composite ceramic powder. Lignin has a multi-benzene ring structure and is a natural macromolecule with a rigid chain structure; the rigid structure also increases its thermal decomposition temperature, making lignin have good heat resistance and good carbonization ability; lignin will form a dense protective carbon layer after high-temperature decarbonization, thereby improving the flame retardant properties of the cable material doped with lignin. Cyanuric chloride, as a polynitrogen and polyhalogen organic small molecule flame retardant, can not only enhance the flame retardant properties of lignin itself by combining with lignin, but also eliminate the chlorine element in cyanuric chloride through nucleophilic substitution reaction to prepare halogen-free coal mine cables.
[0035] 2. In order to enhance the mechanical properties of the prepared cable, the present invention dopes composite ceramic powder into the cable material. Silicon nitride ceramic powder is one of the materials with the most application potential in high-temperature structural ceramics, and is an advanced engineering ceramic with high strength, high fracture toughness and high hardness. The surface of silicon nitride ceramic powder contains -OH groups, and a hydrolysis reaction can occur between the modified silane coupling agent prepared by the present invention and the hydroxyl active groups on the surface of silicon nitride. The modified coupling agent molecules can be distributed on the surface of silicon nitride ceramic powder in a chemical adsorption manner, which not only improves the compatibility between the composite ceramic powder and the organic polymer material, but also blocks the agglomeration phenomenon between micron-sized ceramic powders. The epoxy small molecule groups on the surface of the modified coupling agent can also undergo a ring-opening reaction with the chlorine in the composite flame retardant, further ensuring that the prepared cable material is halogen-free. DETAILED DESCRIPTION
[0036] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than 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.
[0037] Example 1
[0038] This embodiment provides a method for preparing a composite flame retardant for a ceramic low-smoke halogen-free coal mine cable, comprising the following steps:
[0039] S1, 36g of γ-(diethylenetriamine)propyltriethoxysilane were added to a 250mL beaker, and then 100mL of water was added, and the mixture was stirred at 300r / min for 30min to obtain a silanol solution; then 20g of lignin was added to the beaker, and the beaker was transferred to a water bath, heated to 70°C, accompanied by mechanical stirring at 100r / min, and reacted for 2h to obtain a mixed solid-liquid. The mixed solid-liquid was filtered to obtain a solid; the solid was washed three times with deionized water, and the solid was vacuum dried at 70°C to constant weight to obtain a modified lignin.
[0040] S2. Add 45 g of cyanuric chloride, 100 g of anhydrous sodium carbonate and 500 mL of 1,4-dioxane into a 1000 mL three-necked flask, stir at 100 r / min for 10 min to obtain a reaction mixture; then add 50 g of modified lignin into the three-necked flask, and then transfer the three-necked flask to an oil bath, first, react at 0°C for 2 h, then react at 50°C for 2 h, and finally react at 100°C for 2 h to obtain a product; filter the product, and then vacuum dry it at 70°C to constant weight to obtain a composite flame retardant.
[0041] Example 2
[0042] This embodiment provides a method for preparing a composite flame retardant for a ceramic low-smoke halogen-free coal mine cable, comprising the following steps:
[0043] S1, 36g of γ-(diethylenetriamine)propyltriethoxysilane were added to a 250mL beaker, and then 100mL of water was added, and the mixture was stirred at 340r / min for 45min to obtain a silanol solution; then 26g of lignin was added to the beaker, and the beaker was transferred to a water bath, heated to 76°C, accompanied by mechanical stirring at 100-200r / min, and reacted for 2.4h to obtain a mixed solid-liquid. The mixed solid-liquid was filtered to obtain a solid; the solid was washed three times with deionized water, and the solid was vacuum dried at 75°C to constant weight to obtain a modified lignin.
[0044] S2. Add 50 g of cyanuric chloride, 100 g of anhydrous sodium carbonate and 500 mL of 1,4-dioxane into a 1000 mL three-necked flask, stir at 100 r / min for 13 min to obtain a reaction mixture; then add 50 g of modified lignin into the three-necked flask, and then transfer the three-necked flask to an oil bath, first, react at 10°C for 2.5 h, then react at 50°C for 2.5 h, and finally react at 100°C for 2.6 h to obtain a product; filter the product, and then vacuum dry it at 73°C to constant weight to obtain a composite flame retardant.
[0045] Example 3
[0046] This embodiment provides a method for preparing a composite flame retardant for a ceramic low-smoke halogen-free coal mine cable, comprising the following steps:
[0047] S1, 36g of γ-(diethylenetriamine)propyltriethoxysilane were added to a 250mL beaker, and then 100mL of water was added, and the mixture was stirred at 400r / min for 60min to obtain a silanol solution; then 30g of lignin was added to the beaker, and the beaker was transferred to a water bath, heated to 80°C, accompanied by mechanical stirring at 200r / min, and reacted for 3h to obtain a mixed solid-liquid. The mixed solid-liquid was filtered to obtain a solid; the solid was washed three times with deionized water, and the solid was vacuum dried at 80°C to constant weight to obtain a modified lignin.
[0048] S2. Add 55 g of cyanuric chloride, 100 g of anhydrous sodium carbonate and 500 mL of 1,4-dioxane into a 1000 mL three-necked flask, stir at 100 r / min for 20 min to obtain a reaction mixture; then add 50 g of modified lignin into the three-necked flask, and then transfer the three-necked flask to an oil bath, first, react at 20°C for 3 h, then at 50°C for 3 h, and finally at 100°C for 3 h to obtain a product; filter the product, and then vacuum dry it at 80°C to constant weight to obtain a composite flame retardant.
[0049] Example 4
[0050] This embodiment provides a method for preparing a composite ceramic powder for a ceramic low-smoke and halogen-free coal mine cable, comprising the following steps:
[0051] A1. Add silicon nitride ceramics into a planetary ball mill and mill to 100 μm to obtain silicon nitride ceramic powder;
[0052] A2, 20 g of 2-allyl oxirane, 20 g of trimethoxysilane and 1 g of platinum catalyst were added to a 250 mL beaker, the beaker was transferred to a water bath, and the mixture was reacted at 55° C. for 30 min to obtain an organic liquid; the organic liquid was filtered to remove the platinum catalyst, and the organic liquid was subjected to reduced pressure distillation to obtain a modified silane coupling agent; wherein the temperature of the reduced pressure distillation was 50° C., and the pressure of the reduced pressure distillation was 300 MPa.
[0053] A3. Add 200 g of silicon nitride ceramic powder and 20 g of modified silane coupling agent into a 500 mL beaker, mix and stir at 100 r / min for 30 min to obtain a composite flame retardant.
[0054] Example 5
[0055] This embodiment provides a method for preparing a composite ceramic powder for a ceramic low-smoke and halogen-free coal mine cable, comprising the following steps:
[0056] A1. Add silicon nitride ceramics into a planetary ball mill and mill to 1500 μm to obtain silicon nitride ceramic powder;
[0057] A2, 23 g of 2-allyl oxirane, 22 g of trimethoxysilane and 1.5 g of a platinum catalyst were added to a 250 mL beaker, the beaker was transferred to a water bath, and the mixture was reacted at 65° C. for 33 min to obtain an organic liquid; the organic liquid was filtered to remove the platinum catalyst, and the organic liquid was subjected to reduced pressure distillation to obtain a modified silane coupling agent; wherein the temperature of the reduced pressure distillation was 55° C., and the pressure of the reduced pressure distillation was 330 MPa.
[0058] A3. Add 260 g of silicon nitride ceramic powder and 25 g of modified silane coupling agent into a 500 mL beaker, and mix and stir at 180 r / min for 40 min to obtain composite ceramic powder.
[0059] Example 6
[0060] This embodiment provides a method for preparing a composite ceramic powder for a ceramic low-smoke and halogen-free coal mine cable, comprising the following steps:
[0061] A1. Add silicon nitride ceramics into a planetary ball mill and mill to 200 μm to obtain silicon nitride ceramic powder;
[0062] A2, 30g of 2-allyl oxirane, 25g of trimethoxysilane and 2g of platinum catalyst were added to a 250mL beaker, the beaker was transferred to a water bath, and the reaction was carried out at 75°C for 40min to obtain an organic liquid; the organic liquid was filtered to remove the platinum catalyst, and the organic liquid was subjected to reduced pressure distillation to obtain a modified silane coupling agent; wherein the temperature of the reduced pressure distillation was 60°C, and the pressure of the reduced pressure distillation was 400MPa.
[0063] A3. Add 300 g of silicon nitride ceramic powder and 30 g of modified silane coupling agent into a 500 mL beaker, and mix and stir at 200 r / min for 60 min to obtain composite ceramic powder.
[0064] Example 7
[0065] This embodiment provides a method for preparing a ceramic low-smoke and halogen-free coal mine cable, comprising the following steps:
[0066] B1. Dry 50 parts of cross-linked polyethylene and 30 parts of acrylic copolymer at 50°C for 10 hours to obtain dried cross-linked polyethylene and dried acrylic copolymer, respectively; uniformly mix 50 parts of dried cross-linked polyethylene, 30 parts of dried acrylic copolymer, 10 parts of the composite flame retardant prepared in Example 1, and 10 parts of the composite ceramic powder prepared in Example 4, according to parts by weight, to obtain a mixture; then add 2 parts of N-isopropyl-N'-diphenyl-p-phenylenediamine, 2 parts of tribasic lead sulfate and 3 parts of diphenyl octyl phosphate to the mixture, mix again to obtain a raw material.
[0067] B2. Add the raw materials into a torque rheometer, melt-blend for 10 min at 190° C. and 100 r / min to obtain a cable material; then add the cable material into a flat vulcanizer, set the vulcanization temperature at 180° C. and the vulcanization pressure at 15 MPa to obtain a ceramic low-smoke halogen-free coal mine cable.
[0068] Example 8
[0069] This embodiment provides a method for preparing a ceramic low-smoke and halogen-free coal mine cable, comprising the following steps:
[0070] B1. Dry 55 parts of cross-linked polyethylene and 35 parts of acrylic copolymer at 50°C for 11 hours, and obtain dried cross-linked polyethylene and dried acrylic copolymer in turn; uniformly mix 54 parts of dried cross-linked polyethylene, 37 parts of dried acrylic copolymer, 15 parts of the composite flame retardant prepared in Example 2, and 15 parts of the composite ceramic powder prepared in Example 5, according to parts by weight, to obtain a mixture; then add 3 parts of tris(nonylphenyl) phosphite, 3 parts of dibasic lead sulfate and 4 parts of tricresyl phosphate to the mixture, mix again, and obtain a raw material.
[0071] B2. Add the raw materials into a torque rheometer, melt-blend for 10 min at 195° C. and 150 r / min to obtain a cable material; then add the cable material into a flat vulcanizer, set the vulcanization temperature at 1820° C. and the vulcanization pressure at 16 MPa to obtain a ceramic low-smoke halogen-free coal mine cable.
[0072] Example 9
[0073] This embodiment provides a method for preparing a ceramic low-smoke and halogen-free coal mine cable, comprising the following steps:
[0074] B1. Dry 60 parts of cross-linked polyethylene and 40 parts of acrylic copolymer at 50°C for 12 hours to obtain dried cross-linked polyethylene and dried acrylic copolymer in turn; mix 60 parts of dried cross-linked polyethylene, 40 parts of dried acrylic copolymer, 20 parts of the composite flame retardant prepared in Example 3, and 20 parts of the composite ceramic powder prepared in Example 6 in parts by weight to obtain a mixture; then add 4 parts of tris(2,4-di-tert-butyl)phenyl phosphite, 4 parts of dibasic lead phthalate and 5 parts of tricresyl phosphate to the mixture, mix again to obtain a raw material.
[0075] B2. Add the raw materials into a torque rheometer, melt-blend them at 200° C. and 200 r / min for 10 min to obtain a cable material; then add the cable material into a flat vulcanizer, set the vulcanization temperature at 190° C. and the vulcanization pressure at 20 MPa to obtain a ceramic low-smoke halogen-free coal mine cable.
[0076] Comparative Example 1
[0077] The difference between this comparative example and Example 9 is that in step B1, modified lignin and cyanuric chloride are conventionally mixed to replace the composite flame retardant.
[0078] Comparative Example 2
[0079] The difference between this comparative example and Example 9 is that in step B1, cyanuric chloride of equal mass is used to replace the composite flame retardant.
[0080] Comparative Example 3
[0081] The difference between this comparative example and Example 9 is that in step B1, the ceramic powder is not modified by using a silane coupling agent.
[0082] Performance Testing:
[0083] 1. According to GB / T1040-92 "Plastic Tensile Test Method", the mechanical properties of the ceramic low-smoke and halogen-free coal mine cables prepared in Examples 7-9 and Comparative Examples 1-3 were tested using a universal tensile machine. The ceramic low-smoke and halogen-free coal mine cables had a gauge length of 25 mm and a width of 6 mm. The test conditions were a tensile force of 500 N and a tensile speed of 200 mm / min. The tensile strength and elongation at break were recorded respectively.
[0084] 2. The ceramic low-smoke halogen-free coal mine cables prepared in Examples 7-9 and Comparative Examples 1-3 were subjected to a UL-94 vertical combustion test; their flame retardant grades were determined based on the duration of spontaneous combustion.
[0085] The specific test results are shown in Table 1.
[0086] Table 1. Performance test data of samples
[0087]
[0088] Data Analysis:
[0089] Analyzing the data in Table 1, the ceramic low-smoke halogen-free coal mine cables prepared in Examples 7-9 of the present invention all have excellent mechanical properties, as shown by large tensile strength values and elongation at break; however, in Comparative Example 3, since the ceramic powder was not modified with a silane coupling agent, the compatibility between the ceramic powder and the remaining components was poor, resulting in reduced mechanical properties, as shown by reduced tensile strength values and elongation at break values.
[0090] The ceramic low-smoke halogen-free coal mine cables prepared in Examples 7-9 of the present invention all have excellent flame retardant properties; among them, V-0 is the highest flame retardant performance level; however, in Comparative Example 1, the modified lignin did not react with cyanuric chloride, which reduced its own flame retardant properties, showing that the flame retardant level was only V-1; in Comparative Example 2, using a single organic small molecule to replace the organic-inorganic composite flame retardant will reduce its own flame retardant level.
[0091] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.
[0092] In the description of this 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.
[0093] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.
Claims
1. A ceramic low-smoke halogen-free coal mine cable, characterized in that: The invention comprises the following components in parts by weight: 50-60 parts of dried cross-linked polyethylene, 30-40 parts of dried acrylic copolymer, 10-20 parts of composite flame retardant, 10-20 parts of composite ceramic powder, 2-4 parts of antioxidant, 2-4 parts of stabilizer and 3-5 parts of plasticizer.
2. A ceramic low-smoke zero-halogen coal mine cable according to claim 1, characterized in that: The preparation method of the composite flame retardant comprises the following steps: S1, γ-(diethylenetriamine)propyltriethoxysilane and water are mixed and reacted to obtain a silanol liquid; lignin is then added to the silanol liquid, the temperature is raised to 70-80° C., and the reaction is performed for 2-3 hours to obtain a mixed solid-liquid; the mixed solid-liquid is filtered to obtain a solid; the solid is washed with deionized water and vacuum dried to obtain a modified lignin; S2, cyanuric chloride, anhydrous sodium carbonate and 1,4-dioxane are mixed and stirred to obtain a reaction mixture; then modified lignin is added to the reaction mixture, reacted at 0-20°C for 2-3h, then reacted at 50°C for 2-3h, and finally reacted at 100°C for 2-3h to obtain a product; the product is filtered and vacuum dried to obtain a composite flame retardant.
3. A ceramic low-smoke zero-halogen coal mine cable according to claim 2, characterized in that: In step S1, the usage ratio of γ-(diethylenetriamine)propyltriethoxysilane and water is 25-35 g:100 mL, and the vacuum drying temperature is 70-80°C.
4. The ceramic low-smoke zero-halogen coal mine cable according to claim 2, characterized in that: In step S2, the usage ratio of cyanuric chloride, anhydrous sodium carbonate and 1,4-dioxane is 45-55 g:100 g:500 mL, and the vacuum drying temperature is 70-80°C.
5. The ceramic low-smoke zero-halogen coal mine cable according to claim 1, characterized in that: The preparation method of the composite ceramic powder comprises the following steps: A1. Add silicon nitride ceramics into a planetary ball mill and mill to 100-200 μm to obtain silicon nitride ceramic powder; A2, 2-allyl oxirane, trimethoxysilane and a platinum catalyst are mixed and reacted at 55-75° C. for 30-40 minutes to obtain an organic liquid; the organic liquid is filtered to remove the platinum catalyst, and the organic liquid is subjected to reduced pressure distillation to obtain a modified silane coupling agent; A3. Mix and stir silicon nitride ceramic powder and modified silane coupling agent to obtain composite ceramic powder.
6. The ceramic low-smoke zero-halogen coal mine cable according to claim 1, characterized in that: In step A2, the amount ratio of 2-allyl oxirane, trimethoxysilane and platinum catalyst is 20-30g:20-25g:1-2g; the temperature of vacuum distillation is 50-60°C, and the pressure of vacuum distillation is 300-400MPa; in step A3, the amount ratio of silicon nitride ceramic powder and modified silane coupling agent is 200-300g:20-30g.
7. The ceramic low-smoke zero-halogen coal mine cable according to claim 1, characterized in that: The preparation method of the ceramic low-smoke halogen-free coal mine cable comprises the following steps: B1. Dry the cross-linked polyethylene and the acrylic acid copolymer at 50° C. for 10-12 hours in sequence to obtain dried cross-linked polyethylene and dried acrylic acid copolymer, respectively; mix the dried cross-linked polyethylene, the dried acrylic acid copolymer, the modified lignin and the composite ceramic powder to obtain a mixture; then add an antioxidant, a stabilizer and a plasticizer to the mixture, mix again to obtain a raw material; B2. Add the raw materials into a torque rheometer, and perform melt blending at 190-200° C. to obtain a cable material; then add the cable material into a flat vulcanizer, and perform vulcanization at 180-190° C. and 15-20 MPa to obtain a ceramic low-smoke halogen-free coal mine cable.
8. The ceramic low-smoke zero-halogen coal mine cable according to claim 7, characterized in that: In step B1, the antioxidant is any one of N-isopropyl-N'-diphenyl-p-phenylenediamine, tris(nonylphenyl)phosphite, triester phosphite, and tris(2,4-di-tert-butyl)phenyl phosphite; the stabilizer is any one of tribasic lead sulfate, dibasic lead sulfate, or dibasic lead phthalate; and the plasticizer is any one of diphenyl octyl phosphate, trioctyl phosphate, tricresyl phosphate, or tributyl phosphate.