Halogen-free flame-retardant wear-resistant cable and preparation method thereof

Abstract

The invention discloses a halogen-free flame-retardant wear-resistant cable and a preparation method thereof, belongs to the technical field of cable preparation, and is used for solving the technical problem that the wear resistance and flame retardance of a cable in the prior art need to be further improved. The preparation method comprises the following steps: adding a flame-retardant wear-resistant material into a plastic extruding machine, extruding and coating the surface of a shielding layer with the flame-retardant wear-resistant material; the sheath layer is obtained after natural curing, an isocyanate group on the dimethyl isocyanate silane reacts with hydroxyl groups on the polyethylene glycol and the 5-aminoresorcinol to form an isocyanate group-terminated long-chain structure, and a hydroxyl group on the flame-retardant chain extender reacts with the terminated isocyanate group to form a space chain segment structure, so that the flame-retardant flame-retardant sheath layer is formed. And finally, carrying out amino blocking on the inorganic blocking agent to obtain composite polyurethane, mixing the composite polyurethane serving as a main body material with an auxiliary material, and carrying out extrusion curing to obtain a sheath layer of the wear-resistant cable, thereby finally obtaining the high-performance wear-resistant cable.

Description

Technical Field

[0001] The present invention relates to the technical field of cable preparation, and in particular to a halogen-free, flame-retardant, wear-resistant cable and a preparation method thereof. Background Art

[0002] The development of halogen-free flame-retardant and wear-resistant cables has evolved from basic research to widespread application. In the 1980s, with the increasing awareness of environmental protection, traditional halogen-containing flame-retardant cables attracted attention due to the toxic gases released during combustion. In the early stages of halogen-free flame-retardant material research and development, low-smoke halogen-free cables primarily used polyolefin-based materials, with the addition of inorganic flame retardants such as aluminum hydroxide and magnesium hydroxide to enhance flame retardancy, but their wear resistance was relatively poor. In the 21st century, new energy and intelligent manufacturing drove demand growth, and cables needed to balance flame retardancy, wear resistance, and high-temperature resistance. In recent years, under the concepts of green manufacturing and the circular economy, halogen-free flame-retardant and wear-resistant cables have adopted bio-based materials and recyclable formulas to further optimize performance. Technical improvements in extrusion processes and conductor compression technology have reduced costs and improved electrical performance. Currently, the industry is focusing on high durability and low cost to meet more complex application scenarios.

[0003] For example, the prior art CN116487096B discloses a halogen-free, low-smoke, flame-retardant cable and its preparation process. The cable comprises a protective outer layer, an insulating middle layer and a conductor inner layer arranged in sequence from the outside to the inside. The material of the protective outer layer is calculated by weight and comprises: 100 parts of polyethylene resin, 20-40 parts of ethylene-vinyl acetate copolymer, 12-20 parts of flame retardant filler, 4-8 parts of flame retardant additive, 1.5-3 parts of dispersant, 0.5-1 part of lubricant, 1.2-1.8 parts of antioxidant and 0.3-0.7 part of light stabilizer. The cable comprises an inner conductive layer, a middle insulating layer and an outer protective layer. The outer protective layer is made of a halogen-free, flame-retardant resin composite material, which has the advantages of high strength, high wear resistance and high aging resistance, as well as the advantages of low smoke, halogen-free and good flame retardant effect.

[0004] However, the above patent content only prepares a flame retardant filler by surface modification of talc, grafting of pyrimidine derivatives and boric acid reaction, and uses the flame retardant filler as an additive to protect the outer layer to improve the flame retardant and wear resistance of the cable. However, the PE / EVA matrix has low hardness and insufficient wear resistance, and is prone to wear due to long-term friction. In addition, the talc-based flame retardant filler is easy to peel off under mechanical stress, reducing the flame retardant durability. The silicon-based flame retardant has poor compatibility with the matrix and is easy to agglomerate, which weakens the mechanical properties, resulting in the wear resistance of the cable needing to be further improved.

[0005] Moreover, the flame retardant system relies on physical filling, and talc modification only provides physical barrier, lacks efficient charring or gas phase smoke suppression mechanism, and has limited flame retardant effect. There is no strong chemical bond between the flame retardant filler and the matrix, and it is easy to fail after long-term use, which leads to the need for further improvement of the flame retardant performance of this cable. Summary of the Invention

[0006] The object of the present invention is to provide a halogen-free flame-retardant wear-resistant cable and a preparation method thereof, so as to solve the technical problem in the prior art that the wear resistance and flame-retardant properties of the cable need to be further improved.

[0007] The purpose of the present invention can be achieved by the following technical solution: A method for preparing a halogen-free flame-retardant wear-resistant cable comprises the following steps:

[0008] S1. Twisting a plurality of copper wires and coating the surfaces with polyvinylidene fluoride to form a conductor layer;

[0009] S2. After the conductor layer is pulled by a pulling device, it is wrapped with copper tape to obtain a shielding layer;

[0010] S3. Add the flame retardant and wear resistant material into the extruder, extrude and coat it on the surface of the shielding layer, and obtain the sheath layer after natural curing.

[0011] Furthermore, in step S1, the diameter of the copper wire is 0.4-0.5 mm, and the coating thickness of the polyvinylidene chloride is 0.8 mm; in step S2, the thickness of the copper tape is 0.8-0.9 mm, and it is wrapped in two layers; in step S3, the flame retardant and wear-resistant material includes the following raw materials in parts by weight: 80-100 parts of composite polyurethane, 15-20 parts of plasticizer, 2-5 parts of stabilizer, 1-2 parts of lubricant and 1-2 parts of antioxidant.

[0012] Furthermore, the plasticizer is one or both of propylene glycol and ethylene glycol; the stabilizer is one or both of tribasic lead sulfate and dibutyltin dilaurate; the lubricant is one or both of calcium stearate and zinc stearate; and the antioxidant is one or more of triphosphates.

[0013] Furthermore, the temperatures of the eight temperature zones of the extruder from the feed port toward the discharge port are 170°C, 175°C, 175°C, 180°C, 185°C, 190°C, 190°C, and 200°C, respectively; the main engine speed of the twin-screw extruder is 80-120rpm, the pressure is 100-150bar, and the extrusion thickness is 1.2-1.6mm.

[0014] Furthermore, the preparation method of the composite polyurethane comprises the following steps:

[0015] A1. Add polyethylene glycol, 5-aminoresorcinol, N,N-dimethylformamide and dibutyltin dilaurate to a reactor and stir. Raise the temperature of the reactor to 50-60° C., add dimethylsilyl diisocyanate dropwise to the reactor, and keep the temperature for 40-60 min. Add a flame retardant chain extender to the reactor and keep the temperature for 20-30 min. Add an inorganic end-capping agent to the reactor and keep the temperature for 30-40 min. Post-treat to obtain a modified polyurethane.

[0016] A2. Add modified polyurethane, triethylamine and N,N-dimethylformamide to a low-temperature reactor. After nitrogen protection is introduced, the temperature of the reactor is lowered to 0-5°C, and diphenyl chlorophosphate is added dropwise to the reactor. After the temperature is kept constant for 2-3 hours, the temperature of the low-temperature reactor is raised to room temperature, and the reaction is continued at room temperature for 10-12 hours. The composite polyurethane is obtained by post-processing.

[0017] The reaction equation for preparing composite polyurethane is:

[0018]

[0019] The reaction principle for preparing composite polyurethane is as follows: under the promotion of heating and catalyst, the isocyanate group on dimethylsilyl diisocyanate reacts with the hydroxyl groups on polyethylene glycol and 5-aminoresorcinol to form a long-chain structure terminated by isocyanate groups, and the hydroxyl groups on the flame retardant chain extender react with the blocked isocyanate groups to form a spatial segment structure, which is finally terminated by the amino groups on the inorganic capping agent to obtain a composite polyurethane.

[0020] Furthermore, in step A1, the amount ratio of polyethylene glycol, 5-aminoresorcinol, N,N-dimethylformamide, dibutyltin dilaurate, dimethylsilyl diisocyanate, flame retardant chain extender and inorganic end capping agent is 3.6-4.2g:2.7-3.2g:40-50mL:0.3-0.5g:5.4-6.4g:2-3g:4-6g, and the post-treatment includes: after the reaction is completed, after the temperature of the reactor is lowered to room temperature, the reaction solution is transferred to a rotary evaporator with a salt bath temperature of 80-100°C, and reduced pressure distillation is performed until no liquid is extracted to obtain a modified polyurethane;

[0021] Furthermore, in step A2, the amount ratio of modified polyurethane, triethylamine, N,N-dimethylformamide and diphenyl chlorophosphate is 6-7g:1-2g:25-30mL:2-3g, and the post-treatment includes: after the reaction is completed, after the temperature of the reactor is lowered to room temperature, the reaction liquid is transferred to a rotary evaporator with a salt bath temperature of 80-100°C, and distilled under reduced pressure until no liquid is extracted to obtain a composite polyurethane.

[0022] Furthermore, the preparation method of the flame retardant chain extender comprises the following steps:

[0023] B1. Add 4,5-diaminobenzene-1,2-diphenol, imidazole and dichloromethane to a reactor, stir at room temperature for 10-15 minutes, add trimethylchlorosilane to the reactor, stir at room temperature for 10-12 hours, and post-treat to obtain a modified monomer;

[0024] B2. Add the modified monomer, sodium bicarbonate and dimethylformamide to the reactor, add phenylphosphonic dichloride to the reactor continuously at room temperature for 2-3 hours, raise the temperature of the reactor to 100-120°C, keep the temperature for reaction for 10-12 hours, and post-treat to obtain a flame retardant chain extender precursor;

[0025] B3. Add the flame retardant chain extender precursor and anhydrous ethanol to the reactor, stir at room temperature for 10-15 minutes, add 0.2-0.3 mol / L hydrochloric acid aqueous solution to the reactor, keep the temperature and react for 20-24 hours, and then post-treat to obtain the flame retardant chain extender.

[0026] The reaction equation for preparing the flame retardant chain extender is:

[0027]

[0028] The reaction principle for preparing the flame retardant chain extender is as follows: the hydroxyl group on 4,5-diaminobenzene-1,2-diphenol attacks trimethylchlorosilane as a nucleophilic reagent under the activation of imidazole, and the chlorine group is replaced as a leaving group to form a silicon-oxygen bond to obtain a modified monomer. Under alkaline conditions, the deprotonation of the amino group of the modified monomer is promoted to enhance its nucleophilicity and promote its electrophilic substitution reaction with the phosphorus-chlorine group on phenylphosphonyl dichloride, thereby finally preparing a flame retardant chain extender precursor with a long chain structure. Finally, the silane structure is removed by catalysis under acidic conditions in anhydrous ethanol to finally prepare the flame retardant chain extender.

[0029] Furthermore, in step B1, the ratio of 4,5-diaminobenzene-1,2-diphenol, imidazole, dichloromethane and trimethylchlorosilane is 3-4 g: 0.3-0.5 g: 30-36 mL: 5-6 g, and the post-treatment includes: after the reaction is completed, after the temperature of the reactor is lowered to room temperature, the reaction solution is transferred to a rotary evaporator with a salt bath temperature of 80-100 ° C, and distilled under reduced pressure until no liquid is extracted to obtain a modified monomer;

[0030] Furthermore, in step B2, the ratio of the modified monomer, sodium bicarbonate, dimethylformamide and phenylphosphonic dichloride is 4-5g:0.3-0.5g:30-36mL:2-3g, and the post-treatment includes: after the reaction is completed, after the temperature of the reactor is lowered to room temperature, the reaction solution is transferred to a rotary evaporator with a salt bath temperature of 80-100°C, and distilled under reduced pressure until no liquid is extracted to obtain a flame retardant chain extender precursor;

[0031] Furthermore, in step B3, the amount ratio of the flame retardant chain extender precursor, anhydrous ethanol and 0.2-0.3 mol / L hydrochloric acid aqueous solution is 3-4 g: 20-24 mL: 2-3 mL, and the post-treatment includes: after the reaction is completed, after the temperature of the reactor is lowered to room temperature, the reaction liquid is transferred to a rotary evaporator with a salt bath temperature of 80-100 ° C, and reduced pressure distillation is performed until no liquid is extracted to obtain a flame retardant chain extender.

[0032] Furthermore, the preparation method of the inorganic capping agent comprises the following steps:

[0033] C1. Aluminum chloride hexahydrate and deionized water are added to a high-pressure reactor, stirred at room temperature for 5-8 minutes, and then sodium hydroxide powder is added to the reactor. After the addition is continued for 2 hours, magnesium sulfate is added to the reactor, and the high-pressure reactor is transferred to an oven. The oven temperature is increased to 180-200° C. and the reaction is carried out at this temperature for 6-8 hours. Nanowhiskers are obtained by post-processing;

[0034] C2. Add nanowhiskers and deionized water into a reactor and stir. Use 98.0 wt % sulfuric acid aqueous solution to adjust the pH of the reaction system to 3-4, stir at room temperature for 30-40 minutes, and post-treat to obtain etched nanowhiskers.

[0035] C3. Add the etched nanowhiskers, anhydrous ethanol and deionized water into the reactor and stir. The temperature of the reactor is raised to 40-60°C. After adjusting the pH value of the reaction system to 8-9 with a saturated sodium hydroxide aqueous solution, add 4-aminobutyltriethoxysilane into the reactor and keep the temperature to react for 40-60 minutes. After post-treatment, an inorganic capping agent is obtained.

[0036] The reaction principle for preparing the inorganic capping agent is as follows: under alkaline and hydrothermal conditions, aluminum chloride hexahydrate and magnesium sulfate are hydrolyzed to produce a nanowhisker structure, and after acid etching, the siloxy groups on 4-aminobutyltriethoxysilane are hydrolyzed to produce a silanol structure, which reacts with the active functional groups on the etched nanowhiskers to finally prepare the inorganic capping agent.

[0037] Furthermore, in step C1, the ratio of aluminum chloride hexahydrate, deionized water, sodium hydroxide powder, and magnesium sulfate is 2-3 g:100 mL:4-5 g:1-2 g, and the post-treatment includes: after the reaction is completed, after the temperature of the reactor is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, the filter cake is washed 3-5 times with anhydrous ethanol and deionized water, and the filter cake is transferred to a drying oven at a temperature of 60° C. and vacuum dried to constant weight to obtain nanowhiskers;

[0038] Furthermore, in step C2, the ratio of the amount of nanowhiskers to deionized water is 3-4 g: 40-50 mL, and the post-treatment includes: after the reaction is completed, after the temperature of the reactor is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, the filter cake is washed 3-5 times with anhydrous ethanol and deionized water, and the filter cake is transferred to a drying oven at a temperature of 60° C. and vacuum dried to constant weight to obtain etched nanowhiskers;

[0039] Furthermore, in step C3, the ratio of the amount of etched nanowhiskers, anhydrous ethanol, deionized water and 4-aminobutyltriethoxysilane is 2-3g:10-12mL:6-8mL:1-2g, and the post-treatment includes: after the reaction is completed, after the temperature of the reactor is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, the filter cake is washed 3-5 times with anhydrous ethanol and deionized water, and the filter cake is transferred to a drying oven at a temperature of 60°C, and vacuum dried to constant weight to obtain an inorganic capping agent.

[0040] The present invention also provides a halogen-free flame-retardant wear-resistant cable, which is prepared by adopting the above-mentioned method for preparing a halogen-free flame-retardant wear-resistant cable.

[0041] The present invention has the following beneficial effects:

[0042] 1. The composite polyurethane prepared by the present invention is formed by the reaction of dimethylsilyl diisocyanate, polyethylene glycol and 5-aminoresorcinol to form a long-chain structure, which is then cross-linked with a flame retardant chain extender and an inorganic end-capping agent to construct a soft and hard spatial network structure with both flexibility and high strength. The inorganic end-capping agent is hydrolyzed by aluminum chloride hexahydrate and magnesium sulfate to form nanowhiskers, which are strongly bonded to the matrix after silane modification, thereby enhancing surface hardness and wear resistance, while dispersing external forces and reducing wear. The flame retardant chain extender improves the crosslinking density and heat resistance through a long-chain structure containing silicon-oxygen bonds and phosphonyl groups, and reduces chain breakage during wear. The hydrolysis and removal of the silane structure optimizes chemical stability, enhances intermolecular bonding, and reduces surface peeling. The extrusion curing process ensures that the material is dense, reduces defects, and further improves wear resistance. This multi-component synergistic effect forms a high-toughness, high-hardness, and wear-resistant sheath layer, which enables the cable to exhibit excellent durability under friction and mechanical stress, significantly extending its service life.

[0043] 2. The composite polyurethane backbone prepared by the present invention is formed by dimethylsilane diisocyanate, polyethylene glycol and 5-aminoresorcinol, which combines flexibility and stiffness, achieving high tensile resistance while maintaining ductility. The skeleton is cross-linked by a flame-retardant chain extender containing silicon oxygen and phosphine groups, which can increase network density, disperse stress to improve strength and stabilize the chain to prevent stretch-induced fracture. The nanoscale whiskers obtained by hydrolyzing aluminum chloride hexahydrate and magnesium sulfate are supplemented and functionalized with 4-aminobutyltriethoxysilane and anchored to the matrix through silanol-derived covalent bonds. These hard fillers increase tensile strength by transferring stress and increase toughness by hindering crack propagation. The silane chemical composition of the two components ensures strong interfacial bonding, prevents phase separation and optimizes load transfer. The flexible matrix, rigid whisker reinforcement and strong interfacial interaction create a material that performs well in withstanding tension and absorbing energy, thereby providing a wear-resistant cable sheath with excellent mechanical properties.

[0044] 3. The composite polyurethane backbone prepared by the present invention is formed by dimethylsilane diisocyanate, polyethylene glycol and 5-aminoresorcinol, which combines flexibility and stiffness, and achieves high tensile resistance while maintaining ductility. The skeleton is cross-linked by a flame-retardant chain extender, which contains silicon oxygen and phosphine groups, which can increase the network density, disperse stress to improve strength and stabilize the chain to prevent stretch-induced fracture. The nanoscale whiskers obtained by hydrolyzing aluminum chloride hexahydrate and magnesium sulfate are supplemented and functionalized with 4-aminobutyltriethoxysilane and anchored to the matrix through silanol-derived covalent bonds. These hard fillers increase tensile strength by transferring stress and increase toughness by hindering crack propagation. The silane chemical composition of the two components ensures strong interfacial bonding, prevents phase separation and optimizes load transfer. The flexible matrix, rigid whisker reinforcement and strong interface interaction result in a tensile-resistant and wear-resistant cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0046] Figure 1 It is a schematic diagram of the overall three-dimensional structure of the present invention.

[0047] In the figure: 100, conductor layer; 200, shielding layer; 300, sheath layer. DETAILED DESCRIPTION

[0048] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] The calcium stearate used in the present invention was purchased from Shanghai Haohong Biopharmaceutical Technology Co., Ltd. with the product number 1085910.

[0050] The polyethylene glycol used in the present invention was purchased from Nantong Yuyuan New Material Technology Co., Ltd., with the product number being PEG800.

[0051] The polyvinylidene fluoride used in the present invention was purchased from Tianjin Xiens Biochemical Technology Co., Ltd. with the product number of P-85140+500g.

[0052] Example 1

[0053] This embodiment provides a method for preparing an inorganic end-capping agent for preparing a halogen-free, flame-retardant, wear-resistant cable, comprising the following steps:

[0054] Step I: Preparation of nanowhiskers

[0055] Weigh: 60.0g of aluminum chloride hexahydrate and 3000.0mL of deionized water were added to a high-pressure reactor, stirred at room temperature for 5 minutes, and then 120.0g of sodium hydroxide powder was added to the reactor. After continuing to add for 2 hours, 30.0g of magnesium sulfate was added to the reactor, and the high-pressure reactor was transferred to an oven. The oven temperature was raised to 180°C and the reaction was kept warm for 6 hours. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was filtered to collect the filter cake, and the filter cake was washed 3 times with anhydrous ethanol and deionized water. The filter cake was transferred to a drying oven at a temperature of 60°C and vacuum dried to constant weight to obtain nanowhiskers.

[0056] Step II: Preparation of Etched Nanowhiskers

[0057] Weigh: 60.0g nanowhiskers and 800.0mL deionized water were added to the reactor and stirred. After adjusting the pH of the reaction system to 3 with 98.0wt% sulfuric acid aqueous solution, the mixture was stirred at room temperature for 30min. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was filtered to collect the filter cake, and the filter cake was washed three times with anhydrous ethanol and deionized water. The filter cake was transferred to a drying oven at 60°C and vacuum dried to constant weight to obtain etched nanowhiskers.

[0058] Step III: Preparation of Inorganic Capping Agent

[0059] Weigh: 42.0 g of etched nanowhiskers, 210.0 mL of anhydrous ethanol and 120.0 mL of deionized water were added to the reactor and stirred. The temperature of the reactor was raised to 40°C, and the pH of the reaction system was adjusted to 8 with a saturated sodium hydroxide aqueous solution. Then, 20.0 g of 4-aminobutyltriethoxysilane was added to the reactor and the reaction was kept warm for 40 minutes. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was filtered to collect the filter cake, and the filter cake was washed 3 times with anhydrous ethanol and deionized water. The filter cake was transferred to a drying oven at a temperature of 60°C and vacuum dried to constant weight to obtain an inorganic capping agent.

[0060] Example 2

[0061] This embodiment provides a method for preparing an inorganic end-capping agent for preparing a halogen-free, flame-retardant, wear-resistant cable, comprising the following steps:

[0062] Step I: Preparation of nanowhiskers

[0063] Weigh: 90.0g of aluminum chloride hexahydrate and 3000.0mL of deionized water were added to a high-pressure reactor, stirred at room temperature for 8 minutes, and then 150.0g of sodium hydroxide powder was added to the reactor. After continuing to add for 2 hours, 60.0g of magnesium sulfate was added to the reactor, and the high-pressure reactor was transferred to an oven. The oven temperature was raised to 200°C and the reaction was kept warm for 8 hours. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was filtered to collect the filter cake, and the filter cake was washed with anhydrous ethanol and deionized water 5 times. The filter cake was transferred to a drying oven at a temperature of 60°C and vacuum dried to constant weight to obtain nanowhiskers.

[0064] Step II: Preparation of Etched Nanowhiskers

[0065] Weigh: 80.0g nanowhiskers and 1000.0mL deionized water were added to the reactor and stirred. After adjusting the pH of the reaction system to 4 with 98.0wt% sulfuric acid aqueous solution, the mixture was stirred at room temperature for 40min. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was filtered to collect the filter cake, and the filter cake was washed 5 times with anhydrous ethanol and deionized water. The filter cake was transferred to a drying oven at 60°C and vacuum dried to constant weight to obtain etched nanowhiskers.

[0066] Step III: Preparation of Inorganic Capping Agent

[0067] Weigh: 60.0 g of etched nanowhiskers, 360.0 mL of anhydrous ethanol and 240.0 mL of deionized water were added to the reactor and stirred. The temperature of the reactor was raised to 40°C, and the pH of the reaction system was adjusted to 9 with a saturated sodium hydroxide aqueous solution. Then, 40.0 g of 4-aminobutyltriethoxysilane was added to the reactor and kept warm for 40 minutes. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was filtered to collect the filter cake, and the filter cake was washed 5 times with anhydrous ethanol and deionized water. The filter cake was transferred to a drying oven at a temperature of 60°C and vacuum dried to constant weight to obtain an inorganic capping agent.

[0068] Example 3

[0069] This embodiment provides a method for preparing an inorganic end-capping agent for preparing a halogen-free, flame-retardant, wear-resistant cable, comprising the following steps:

[0070] Step I: Preparation of nanowhiskers

[0071] Weigh: 75.0g of aluminum chloride hexahydrate and 3000.0mL of deionized water were added to a high-pressure reactor, stirred at room temperature for 8 minutes, and then 150.0g of sodium hydroxide powder was added to the reactor. After continuing to add for 2 hours, 45.0g of magnesium sulfate was added to the reactor, and the high-pressure reactor was transferred to an oven. The oven temperature was raised to 180°C and the reaction was kept warm for 7 hours. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was filtered to collect the filter cake, and the filter cake was washed 4 times with anhydrous ethanol and deionized water. The filter cake was transferred to a drying oven at a temperature of 60°C and vacuum dried to constant weight to obtain nanowhiskers.

[0072] Step II: Preparation of Etched Nanowhiskers

[0073] Weigh: 72.0g nanowhiskers and 800.0mL deionized water were added to the reactor and stirred. After adjusting the pH of the reaction system to 3 with 98.0wt% sulfuric acid aqueous solution, the mixture was stirred at room temperature for 36min. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was filtered to collect the filter cake, and the filter cake was washed 4 times with anhydrous ethanol and deionized water. The filter cake was transferred to a drying oven at 60°C and vacuum dried to constant weight to obtain etched nanowhiskers.

[0074] Step III: Preparation of Inorganic Capping Agent

[0075] Weigh: 50.0 g of etched nanowhiskers, 240.0 mL of anhydrous ethanol and 160.0 mL of deionized water were added to the reactor and stirred. The temperature of the reactor was raised to 50°C, and the pH of the reaction system was adjusted to 9 with a saturated sodium hydroxide aqueous solution. Then, 30.0 g of 4-aminobutyltriethoxysilane was added to the reactor and the reaction was kept warm for 50 minutes. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was filtered to collect the filter cake, and the filter cake was washed 4 times with anhydrous ethanol and deionized water. The filter cake was transferred to a drying oven at a temperature of 60°C and vacuum dried to constant weight to obtain an inorganic capping agent.

[0076] Example 4

[0077] This embodiment provides a method for preparing a flame retardant chain extender for preparing a halogen-free flame retardant wear-resistant cable, comprising the following steps:

[0078] Step ①, preparation of modified monomer

[0079] Weigh: 30.0g 4,5-diaminobenzene-1,2-diphenol, 3.0g imidazole and 300.0mL dichloromethane are added to the reactor, stirred at room temperature for 10 minutes, and then 50.0g trimethylsilyl chloride is added to the reactor and stirred at room temperature for 10 hours. After the reaction is completed, the temperature of the reactor is lowered to room temperature, and the reaction liquid is transferred to a rotary evaporator with a salt bath temperature of 80°C, and distilled under reduced pressure until no liquid is extracted to obtain a modified monomer.

[0080] Step ②: Preparation of flame retardant chain extender precursor

[0081] Weigh: 40.0g of modified monomer, 3.0g of sodium bicarbonate and 300.0mL of dimethylformamide are added to the reactor, and 20.0g of phenylphosphonic dichloride is continuously added dropwise to the reactor at room temperature for 2h. The temperature of the reactor is raised to 100°C and kept warm for 10h. After the reaction is completed, the temperature of the reactor is lowered to room temperature, and the reaction liquid is transferred to a rotary evaporator with a salt bath temperature of 80°C, and distilled under reduced pressure until no liquid is extracted to obtain a flame retardant chain extender precursor.

[0082] Step 3: Preparation of flame retardant chain extender

[0083] Weigh: 30.0g of flame retardant chain extender precursor and 200.0mL of anhydrous ethanol were added to the reactor, stirred at room temperature for 15min, and then 20.0mL of 0.2mol / L hydrochloric acid aqueous solution was added dropwise to the reactor, and the reaction was kept warm for 20h. After the reaction was completed, the temperature of the reactor was lowered to room temperature, and the reaction liquid was transferred to a rotary evaporator with a salt bath temperature of 80°C, and distilled under reduced pressure until no liquid was extracted to obtain a flame retardant chain extender.

[0084] Example 5

[0085] This embodiment provides a method for preparing a flame retardant chain extender for preparing a halogen-free flame retardant wear-resistant cable, comprising the following steps:

[0086] Step ①, preparation of modified monomer

[0087] Weigh: 40.0g 4,5-diaminobenzene-1,2-diphenol, 5.0g imidazole and 360.0mL dichloromethane are added to the reactor, stirred at room temperature for 15min, and then 60.0g trimethylsilyl chloride is added to the reactor and stirred at room temperature for 12h. After the reaction is completed, the temperature of the reactor is lowered to room temperature, and the reaction liquid is transferred to a rotary evaporator with a salt bath temperature of 100°C, and distilled under reduced pressure until no liquid is extracted to obtain a modified monomer.

[0088] Step ②: Preparation of flame retardant chain extender precursor

[0089] Weigh: 50.0g modified monomer, 5.0g sodium bicarbonate and 360.0mL dimethylformamide are added to the reactor, and 30.0g phenylphosphonic dichloride is continuously added dropwise to the reactor at room temperature for 3h. The temperature of the reactor is raised to 120°C and kept warm for 12h. After the reaction is completed, the temperature of the reactor is lowered to room temperature, and the reaction liquid is transferred to a rotary evaporator with a salt bath temperature of 100°C, and distilled under reduced pressure until no liquid is extracted to obtain a flame retardant chain extender precursor.

[0090] Step 3: Preparation of flame retardant chain extender

[0091] Weigh: 40.0g of flame retardant chain extender precursor and 240.0mL of anhydrous ethanol were added to the reactor, stirred at room temperature for 15min, and then 30.0mL of 0.3mol / L hydrochloric acid aqueous solution was added dropwise to the reactor, and the reaction was kept warm for 24h. After the reaction was completed, the temperature of the reactor was lowered to room temperature, and the reaction liquid was transferred to a rotary evaporator with a salt bath temperature of 100°C, and distilled under reduced pressure until no liquid was extracted to obtain a flame retardant chain extender.

[0092] Example 6

[0093] This embodiment provides a method for preparing a flame retardant chain extender for preparing a halogen-free flame retardant wear-resistant cable, comprising the following steps:

[0094] Step ①, preparation of modified monomer

[0095] Weigh: 36.0g 4,5-diaminobenzene-1,2-diphenol, 4.0g imidazole and 320.0mL dichloromethane are added to the reactor, stirred at room temperature for 12 minutes, and then 54.0g trimethylsilyl chloride is added to the reactor and stirred at room temperature for 12 hours. After the reaction is completed, the temperature of the reactor is lowered to room temperature, and the reaction liquid is transferred to a rotary evaporator with a salt bath temperature of 90°C, and distilled under reduced pressure until no liquid is extracted to obtain a modified monomer.

[0096] Step ②: Preparation of flame retardant chain extender precursor

[0097] Weigh: 48.0g of modified monomer, 4.0g of sodium bicarbonate and 320.0mL of dimethylformamide were added to the reactor, and 24.0g of phenylphosphonic dichloride was continuously added dropwise to the reactor at room temperature for 2h. The temperature of the reactor was raised to 120°C and kept warm for 12h. After the reaction was completed, the temperature of the reactor was lowered to room temperature, and the reaction liquid was transferred to a rotary evaporator with a salt bath temperature of 90°C, and distilled under reduced pressure until no liquid was extracted to obtain a flame retardant chain extender precursor.

[0098] Step 3: Preparation of flame retardant chain extender

[0099] Weigh: 36.0g flame retardant chain extender precursor and 210.0mL anhydrous ethanol are added to the reactor, stirred at room temperature for 12min, and then 24.0mL 0.3mol / L hydrochloric acid aqueous solution is added dropwise to the reactor, and the reaction is kept warm for 21h. After the reaction is completed, after the temperature of the reactor is lowered to room temperature, the reaction liquid is transferred to a rotary evaporator with a salt bath temperature of 90°C, and distilled under reduced pressure until no liquid is extracted to obtain a flame retardant chain extender.

[0100] Example 7

[0101] This embodiment provides a method for preparing a halogen-free, flame-retardant, wear-resistant composite polyurethane for cable preparation, comprising the following steps:

[0102] Step (i), preparation of modified polyurethane

[0103] Weigh: 36.0g polyethylene glycol, 27.0g 5-aminoresorcinol, 400.0mL N,N-dimethylformamide and 3.0g dibutyltin dilaurate were added to the reactor and stirred. The temperature of the reactor was raised to 50°C, 54.0g dimethylsilyl diisocyanate was added dropwise to the reactor, and the reaction was kept warm for 40min. 20.0g of the flame retardant chain extender prepared in Example 4 was added to the reactor, and the reaction was kept warm for 20min. 40.0g of the inorganic end capping agent prepared in Example 1 was added to the reactor, and the reaction was kept warm for 30min. After the reaction was completed, the temperature of the reactor was lowered to room temperature, and the reaction solution was transferred to a rotary evaporator with a salt bath temperature of 80°C, and distilled under reduced pressure until no liquid was extracted to obtain a modified polyurethane.

[0104] Step (ii): Preparation of composite polyurethane

[0105] Weigh: 60.0g modified polyurethane, 10.0g triethylamine and 250.0mL N,N-dimethylformamide are added to a low-temperature reactor. After nitrogen protection is introduced, the temperature of the reactor is reduced to 5°C, and 20.0g diphenyl chlorophosphate is added dropwise to the reactor. After the addition is kept warm for 2-3h, the temperature of the low-temperature reactor is raised to room temperature, and the reaction is continued at room temperature for 10h. After the reaction is completed, after the temperature of the reactor is reduced to room temperature, the reaction liquid is transferred to a rotary evaporator with a salt bath temperature of 100°C, and distilled under reduced pressure until no liquid is extracted to obtain a composite polyurethane.

[0106] Example 8

[0107] This embodiment provides a method for preparing a halogen-free, flame-retardant, wear-resistant composite polyurethane for cable preparation, comprising the following steps:

[0108] Step (i), preparation of modified polyurethane

[0109] Weigh: 42.0g polyethylene glycol, 32.0g 5-aminoresorcinol, 500.0mL N,N-dimethylformamide and 5.0g dibutyltin dilaurate were added to the reactor and stirred. The temperature of the reactor was raised to 60°C. 64.0g dimethylsilyl diisocyanate was added dropwise to the reactor and kept warm for 60min. 30.0g of the flame retardant chain extender prepared in Example 5 was added to the reactor and kept warm for 30min. 60.0g of the inorganic end capping agent prepared in Example 2 was added to the reactor and kept warm for 40min. After the reaction was completed, the temperature of the reactor was lowered to room temperature, and the reaction solution was transferred to a rotary evaporator with a salt bath temperature of 100°C and distilled under reduced pressure until no liquid was extracted to obtain a modified polyurethane.

[0110] Step (ii): Preparation of composite polyurethane

[0111] Weigh: 70.0g modified polyurethane, 20.0g triethylamine and 300.0mL N,N-dimethylformamide are added to a low-temperature reactor. After nitrogen protection is introduced, the temperature of the reactor is reduced to 0°C, and 30.0g diphenyl chlorophosphate is added dropwise to the reactor. After the addition is kept warm for 3 hours, the temperature of the low-temperature reactor is raised to room temperature, and the reaction is continued at room temperature for 12 hours. After the reaction is completed, after the temperature of the reactor is reduced to room temperature, the reaction liquid is transferred to a rotary evaporator with a salt bath temperature of 100°C, and distilled under reduced pressure until no liquid is extracted to obtain a composite polyurethane.

[0112] Example 9

[0113] This embodiment provides a method for preparing a halogen-free, flame-retardant, wear-resistant composite polyurethane for cable preparation, comprising the following steps:

[0114] Step (i), preparation of modified polyurethane

[0115] Weigh: 40.0g polyethylene glycol, 30.0g 5-aminoresorcinol, 480.0mL N,N-dimethylformamide and 4.0g dibutyltin dilaurate were added to the reactor and stirred. The temperature of the reactor was raised to 54°C, 60.0g dimethylsilyl diisocyanate was added dropwise to the reactor, and the reaction was kept warm for 50min. 25.0g of the flame retardant chain extender prepared in Example 6 was added to the reactor, and the reaction was kept warm for 25min. 50.0g of the inorganic end capping agent prepared in Example 3 was added to the reactor, and the reaction was kept warm for 36min. After the reaction was completed, the temperature of the reactor was lowered to room temperature, and the reaction solution was transferred to a rotary evaporator with a salt bath temperature of 90°C, and distilled under reduced pressure until no liquid was extracted to obtain a modified polyurethane.

[0116] Step (ii): Preparation of composite polyurethane

[0117] Weigh: 64.0g modified polyurethane, 16.0g triethylamine and 300.0mL N,N-dimethylformamide are added to a low-temperature reactor. After nitrogen protection, the reactor temperature is reduced to 3°C, and 24.0g diphenyl chlorophosphate is added dropwise to the reactor. After the addition is kept warm for 2h, the temperature of the low-temperature reactor is raised to room temperature, and the reaction is continued at room temperature for 12h. After the reaction is completed, after the reactor temperature is reduced to room temperature, the reaction liquid is transferred to a rotary evaporator with a salt bath temperature of 90°C, and distilled under reduced pressure until no liquid is extracted to obtain a composite polyurethane.

[0118] Example 10

[0119] This embodiment provides a method for preparing a halogen-free flame-retardant wear-resistant cable, comprising the following steps:

[0120] Step 1: Prepare the conductor layer

[0121] Seven copper wires with a radius of 0.4 mm are twisted together and then coated with polyvinylidene fluoride with a thickness of 0.8 mm to form a conductor layer 100 .

[0122] Step 2: Prepare the shielding layer

[0123] After the conductor layer is pulled by a pulling device, it is wrapped with a copper tape with a thickness of 0.9 mm. After wrapping two layers, the shielding layer 200 is obtained.

[0124] Step 3: Prepare the sheath layer

[0125] Weigh: 80 parts of the composite polyurethane prepared in Example 7, 15 parts of propylene glycol, 2 parts of dibutyltin dilaurate, 1 part of calcium stearate and 1 part of triphosphate and add them to the extruder. The temperatures of the eight temperature zones of the extruder from the feed port toward the discharge port are 170°C, 175°C, 175°C, 180°C, 185°C, 190°C, 190°C, and 200°C, respectively. The main engine speed of the twin-screw extruder is 80rpm, the pressure is 100bar, and the extrusion coating is applied to the surface of the shielding layer. The extrusion thickness is 1.2mm, and the sheath layer 300 is obtained after natural curing.

[0126] Example 11

[0127] This embodiment provides a method for preparing a halogen-free flame-retardant wear-resistant cable, comprising the following steps:

[0128] Step 1: Prepare the conductor layer

[0129] Seven copper wires with a radius of 0.5 mm are twisted together and then coated with polyvinylidene fluoride with a thickness of 0.8 mm to form a conductor layer 100 .

[0130] Step 2: Prepare the shielding layer

[0131] After the conductor layer is pulled by a pulling device, it is wrapped with a copper tape with a thickness of 0.9 mm. After wrapping two layers, the shielding layer 200 is obtained.

[0132] Step 3: Prepare the sheath layer

[0133] Weigh: 100 parts of the composite polyurethane prepared in Example 8, 20 parts of propylene glycol, 5 parts of dibutyltin dilaurate, 2 parts of calcium stearate and 2 parts of triphosphate and add them into the extruder. The temperatures of the eight temperature zones of the extruder from the feed port toward the discharge port are 170°C, 175°C, 175°C, 180°C, 185°C, 190°C, 190°C and 200°C, respectively. The main speed of the twin-screw extruder is 120rpm, the pressure is 150bar, and the extrusion is coated on the surface of the shielding layer. The extrusion thickness is 1.6mm. After natural curing, the sheath layer 300 is obtained.

[0134] Example 12

[0135] This embodiment provides a method for preparing a halogen-free flame-retardant wear-resistant cable, comprising the following steps:

[0136] Step 1: Prepare the conductor layer

[0137] Seven copper wires with a radius of 0.5 mm are twisted together and then coated with polyvinylidene fluoride with a thickness of 0.8 mm to form a conductor layer 100 .

[0138] Step 2: Prepare the shielding layer

[0139] After the conductor layer is pulled by a pulling device, it is wrapped with a copper tape with a thickness of 0.9 mm. After wrapping two layers, the shielding layer 200 is obtained.

[0140] Step 3: Prepare the sheath layer

[0141] Weigh: 90 parts of the composite polyurethane prepared in Example 9, 18 parts of propylene glycol, 4 parts of dibutyltin dilaurate, 2 parts of calcium stearate and 2 parts of triphosphate and add them into the extruder. The temperatures of the eight temperature zones of the extruder from the feed port toward the discharge port are 170°C, 175°C, 175°C, 180°C, 185°C, 190°C, 190°C and 200°C, respectively. The main speed of the twin-screw extruder is 100rpm, the pressure is 120bar, and the extrusion is coated on the surface of the shielding layer. The extrusion thickness is 1.5mm. After natural curing, the sheath layer 300 is obtained.

[0142] Comparative Example 1

[0143] The difference between this comparative example and Example 12 is that step (ii) is omitted during the preparation of the composite polyurethane used in step (iii).

[0144] Comparative Example 2

[0145] The difference between this comparative example and Example 12 is that the flame retardant chain extender is not used during the preparation of the composite polyurethane used in step 3.

[0146] Comparative Example 3

[0147] The difference between this comparative example and Example 12 is that, in the preparation process of the composite polyurethane used in step 3, the inorganic capping agent is omitted.

[0148] Performance testing:

[0149] The volume wear of the wear-resistant cables prepared in Examples 10-12 and Comparative Examples 1-3 was tested in accordance with the standard GB / T 9867-2008 "Determination of wear resistance of vulcanized rubber or thermoplastic rubber (rotating roller abrader method)".

[0150] The flame retardancy of the wear-resistant cables prepared in Examples 10-12 and Comparative Examples 1-3 was tested with reference to the standard XF 306.1-2007 "Classification and requirements of flame retardant and fire-resistant cables with plastic insulation Part 1: Flame retardant cables".

[0151] The tensile strength of the wear-resistant cables prepared in Examples 10-12 and Comparative Examples 1-3 was tested with reference to the standard XF 306.1-2007 "Classification and requirements of flame-retardant and fire-resistant cables with plastic insulation Part 1: Flame-retardant cables".

[0152] The tensile strength and smoke density of the wear-resistant cables prepared in Examples 10-12 and Comparative Examples 1-3 were tested with reference to the standard GB / T 32129-2015 “Halogen-free and low-smoke flame-retardant cable materials for wires and cables”. Specific data are shown in Table 1.

[0153] Table 1 - Performance test data of each sample

[0154] Data Analysis:

[0155] Comparing and analyzing the data in Table 1, it can be found that the volume wear of the wear-resistant cable prepared by the present invention is 28mm 3 The flame retardant grade is IA, the tensile strength is 24.3MPa, the tensile strength is 70.5MPa, and the smoke density when burning with flame is 104 and the smoke density when burning without flame is 51. All the data are better than the comparative example, indicating that:

[0156] The composite polyurethane prepared by the present invention is formed by the reaction of dimethylsilyl diisocyanate, polyethylene glycol and 5-aminoresorcinol to form a long-chain structure, which is then cross-linked with a flame retardant chain extender and an inorganic end-capping agent to construct a soft and hard spatial network structure with both flexibility and high strength. The inorganic end-capping agent is hydrolyzed by aluminum chloride hexahydrate and magnesium sulfate to form nano whiskers, which are strongly bonded to the matrix after silane modification, thereby enhancing surface hardness and wear resistance, while dispersing external forces and reducing wear. The flame retardant chain extender improves the cross-linking density and heat resistance through a long-chain structure containing silicon-oxygen bonds and phosphonyl groups, and reduces chain breakage during wear. The hydrolysis and removal of the silane structure optimizes chemical stability, enhances intermolecular bonding, and reduces surface peeling. The extrusion curing process ensures material density, reduces defects, and further improves wear resistance. This multi-component synergistic effect forms a high-toughness, high-hardness, and wear-resistant sheath layer, which enables the cable to exhibit excellent durability under friction and mechanical stress, significantly extending its service life.

[0157] The composite polyurethane backbone prepared by the present invention is formed by dimethylsilane diisocyanate, polyethylene glycol and 5-aminoresorcinol, combining flexibility and rigidity, achieving high tensile resistance while maintaining ductility. The backbone is cross-linked by a flame-retardant chain extender containing siloxane and phosphine groups, which can increase network density, disperse stress to improve strength and stabilize the chain to prevent stretch-induced fracture. Nanoscale whiskers obtained by hydrolyzing aluminum chloride hexahydrate and magnesium sulfate are supplemented and functionalized with 4-aminobutyltriethoxysilane to anchor to the matrix through silanol-derived covalent bonds. These hard fillers improve tensile strength by transferring stress and improve toughness by hindering crack propagation. The silane chemical composition of the two components ensures strong interfacial bonding, prevents phase separation and optimizes load transfer. The flexible matrix, rigid whisker reinforcement and strong interfacial interaction result in a tensile-resistant and wear-resistant cable.

[0158] The flame retardant chain extender prepared by the present invention contains phosphorus and siloxy groups from 4,5-diaminobenzene-1,2-diol and phenylphosphonic acid dichloride, which promotes the dehydration of organic materials during combustion to form a thermally stable carbonaceous layer. Silicon decomposes into silicon dioxide, which strengthens the carbide to block heat and oxygen, thereby suppressing flames and smoke. Nano-scale whiskers made from hydrolyzed aluminum chloride hexahydrate and magnesium sulfate are used as a supplement and functionalized with 4-aminobutyltriethoxysilane to enhance thermal stability. The whiskers are bonded through silanol groups to provide carbonization. The silica structure further reduces the emission of flammable gases and smoke. The polyurethane matrix is ​​cross-linked with the chain extender and terminated with whiskers to form a dense network, which limits the release of volatiles and ensures the integrity of the carbide structure. The silane-derived covalent bonds ensure uniform dispersion and cohesion, maximizing the flame retardant efficiency. Ultimately, through phosphorus-driven carbonization, silicon-reinforced silica barrier layer, thermally stable whiskers and a strong matrix, the cable is provided with excellent flame retardancy and low smoke density, thereby significantly improving the flame retardant performance of the wear-resistant cable.

[0159] Finally, it is explained that under alkaline and hydrothermal conditions, aluminum chloride hexahydrate and magnesium sulfate are hydrolyzed to produce nanowhisker structures, and after acid etching, the siloxy groups on 4-aminobutyltriethoxysilane are hydrolyzed to produce silanol structures, which react with the active functional groups on the etched nanowhiskers to finally prepare an inorganic capping agent; the hydroxyl groups on 4,5-diaminobenzene-1,2-diphenol, under the activation of imidazole, attack trimethylchlorosilane as a nucleophilic reagent, and the chlorine group is replaced as a leaving group to form a silicon-oxygen bond to obtain a modified monomer, and under alkaline conditions, the modified monomer undergoes an electrophilic substitution reaction with the phosphorus chloride group on phenylphosphonyl dichloride to finally prepare a long-chain flame retardant chain extender precursor. The invention relates to a method for preparing a flame retardant chain extender, wherein the flame retardant chain extender is prepared by removing the silane structure through catalysis under acidic conditions in anhydrous ethanol; under the promotion of heating and catalyst, the isocyanate group on dimethylsilyl diisocyanate reacts with the hydroxyl groups on polyethylene glycol and 5-aminoresorcinol to form a long chain structure terminated by isocyanate groups, and the hydroxyl groups on the flame retardant chain extender react with the blocked isocyanate groups to form a spatial segment structure, and finally the composite polyurethane is obtained by amino blocking on the inorganic blocking agent. The composite polyurethane is used as the main material and mixed with auxiliary materials, and extrusion and curing are performed to obtain the sheath layer of the wear-resistant cable, and finally a high-performance wear-resistant cable is obtained.

[0160] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a halogen-free flame-retardant wear-resistant cable, characterized in that: The following steps are involved: S1, twisting a plurality of copper wires and coating the surfaces with polyvinylidene fluoride to form a conductor layer (100); S2, after the conductor layer (100) is pulled by a pulling device, it is wrapped with a copper tape to obtain a shielding layer (200); S3. Add the flame retardant and wear resistant material into an extruder, extrude and coat it on the surface of the shielding layer (200), and naturally solidify to obtain the sheath layer (300), wherein the flame retardant and wear resistant material comprises the following raw materials in parts by weight: 80-100 parts of composite polyurethane, 15-20 parts of plasticizer, 2-5 parts of stabilizer, 1-2 parts of lubricant and 1-2 parts of antioxidant.

2. The method for preparing a halogen-free flame-retardant wear-resistant cable according to claim 1, characterized in that: The preparation method of composite polyurethane comprises the following steps: A1. Add polyethylene glycol, 5-aminoresorcinol, N,N-dimethylformamide and dibutyltin dilaurate to a reactor and stir. Raise the temperature of the reactor to 50-60° C., add dimethylsilyl diisocyanate dropwise to the reactor, and keep the temperature for 40-60 min. Add a flame retardant chain extender to the reactor and keep the temperature for 20-30 min. Add an inorganic end-capping agent to the reactor and keep the temperature for 30-40 min. Post-treat to obtain a modified polyurethane. A2. Add modified polyurethane, triethylamine and N,N-dimethylformamide to a low-temperature reactor. After nitrogen protection is introduced, the temperature of the reactor is lowered to 0-5°C, and diphenyl chlorophosphate is added dropwise to the reactor. After the temperature is kept constant for 2-3 hours, the temperature of the low-temperature reactor is raised to room temperature, and the reaction is continued at room temperature for 10-12 hours. The composite polyurethane is obtained by post-processing.

3. The method for preparing a halogen-free flame-retardant wear-resistant cable according to claim 2, characterized in that: In step A1, the amount ratio of the polyethylene glycol, 5-aminoresorcinol, N,N-dimethylformamide, dibutyltin dilaurate, dimethylsilyl diisocyanate, flame retardant chain extender and inorganic end capping agent is 3.6-4.2g:2.7-3.2g:40-50mL:0.3-0.5g:5.4-6.4g:2-3g:4-6g; in step A2, the amount ratio of the modified polyurethane, triethylamine, N,N-dimethylformamide and diphenyl chlorophosphate is 6-7g:1-2g:25-30mL:2-3g.

4. The method for preparing a halogen-free flame-retardant wear-resistant cable according to claim 2, characterized in that: The preparation method of the flame retardant chain extender comprises the following steps: B1. Add 4,5-diaminobenzene-1,2-diphenol, imidazole and dichloromethane to a reactor, stir at room temperature for 10-15 minutes, add trimethylchlorosilane to the reactor, stir at room temperature for 10-12 hours, and post-treat to obtain a modified monomer; B2. Add the modified monomer, sodium bicarbonate and dimethylformamide to the reactor, add phenylphosphonic dichloride to the reactor continuously at room temperature for 2-3 hours, raise the temperature of the reactor to 100-120°C, keep the temperature for reaction for 10-12 hours, and post-treat to obtain a flame retardant chain extender precursor; B3. Add the flame retardant chain extender precursor and anhydrous ethanol to the reactor, stir at room temperature for 10-15 minutes, add 0.2-0.3 mol / L hydrochloric acid aqueous solution to the reactor, keep the temperature and react for 20-24 hours, and then post-treat to obtain the flame retardant chain extender.

5. The method for preparing a halogen-free flame-retardant wear-resistant cable according to claim 4, characterized in that: In step B1, the amount ratio of the 4,5-diaminobenzene-1,2-diphenol, imidazole, dichloromethane and trimethylchlorosilane is 3-4g:0.3-0.5g:30-36mL:5-6g; in step B2, the amount ratio of the modified monomer, sodium bicarbonate, dimethylformamide and phenylphosphonic dichloride is 4-5g:0.3-0.5g:30-36mL:2-3g; in step B3, the amount ratio of the flame retardant chain extender precursor, anhydrous ethanol and 0.2-0.3mol / L hydrochloric acid aqueous solution is 3-4g:20-24mL:2-3mL.

6. The method for preparing a halogen-free flame-retardant wear-resistant cable according to claim 2, characterized in that: The preparation method of the inorganic capping agent comprises the following steps: C1. Aluminum chloride hexahydrate and deionized water are added to a high-pressure reactor, stirred at room temperature for 5-8 minutes, and then sodium hydroxide powder is added to the reactor. After the addition is continued for 2 hours, magnesium sulfate is added to the reactor, and the high-pressure reactor is transferred to an oven. The oven temperature is increased to 180-200° C. and the reaction is carried out at this temperature for 6-8 hours. Nanowhiskers are obtained by post-processing; C2. Add nanowhiskers and deionized water into a reactor and stir. Use 98.0 wt % sulfuric acid aqueous solution to adjust the pH of the reaction system to 3-4, stir at room temperature for 30-40 minutes, and post-treat to obtain etched nanowhiskers. C3. Add the etched nanowhiskers, anhydrous ethanol and deionized water into the reactor and stir. The temperature of the reactor is raised to 40-60°C. After adjusting the pH value of the reaction system to 8-9 with a saturated sodium hydroxide aqueous solution, add 4-aminobutyltriethoxysilane into the reactor and keep the temperature to react for 40-60 minutes. After post-treatment, an inorganic capping agent is obtained.

7. The method for preparing a halogen-free flame-retardant wear-resistant cable according to claim 6, characterized in that: In step C1, the amount ratio of the aluminum chloride hexahydrate, deionized water, sodium hydroxide powder and magnesium sulfate is 2-3g:100mL:4-5g:1-2g; in step C2, the amount ratio of the nanowhiskers and deionized water is 3-4g:40-50mL; in step C3, the amount ratio of the etching nanowhiskers, anhydrous ethanol, deionized water and 4-aminobutyltriethoxysilane is 2-3g:10-12mL:6-8mL:1-2g.

8. A halogen-free flame-retardant wear-resistant cable, characterized in that: The halogen-free flame-retardant wear-resistant cable is prepared by the preparation method of a halogen-free flame-retardant wear-resistant cable according to any one of claims 1 to 7.

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