A halogen-free flame-retardant wear-resistant cable and its preparation method

Abstract

This invention discloses a halogen-free flame-retardant wear-resistant cable and its preparation method, belonging to the field of cable manufacturing technology. It addresses the technical problem that the wear resistance and flame-retardant properties of existing cables need further improvement. The invention includes the following steps: adding flame-retardant and wear-resistant material to an extruder, extruding it to coat the surface of a shielding layer, and allowing it to cure naturally to obtain a sheath layer. This is achieved by reacting the isocyanate groups on dimethyl diisocyanate with the hydroxyl groups on polyethylene glycol and 5-aminoresorcinol to form a long-chain structure with isocyanate groups at the end. Furthermore, the reaction of the hydroxyl groups on a flame-retardant chain extender with the isocyanate groups at the end forms a spatial chain segment structure. Finally, the composite polyurethane is obtained by end-capping with an inorganic end-capping agent. The composite polyurethane is then used as the main material and mixed with auxiliary materials, extruded and cured to obtain the sheath layer of the wear-resistant cable, ultimately resulting in a high-performance wear-resistant cable.

Description

Technical Field

[0001] This invention relates to the field of cable manufacturing technology, specifically to a halogen-free flame-retardant wear-resistant cable and its manufacturing method. Background Technology

[0002] The development of halogen-free flame-retardant and wear-resistant cables has evolved from basic research to widespread application. In the 1980s, with increasing environmental awareness, traditional halogen-containing flame-retardant cables attracted attention due to the release of toxic gases during combustion. In the early stages of halogen-free flame-retardant material research, low-smoke halogen-free cables mainly used polyolefin-based materials, adding inorganic flame retardants such as aluminum hydroxide and magnesium hydroxide to improve flame retardancy, but with poor wear resistance. In the 21st century, new energy and intelligent manufacturing drove demand growth, requiring cables to balance flame retardancy, wear resistance, and high-temperature resistance. In recent years, under the concepts of green manufacturing and circular economy, halogen-free flame-retardant and wear-resistant cables have adopted bio-based materials and recyclable formulas to further optimize performance. Technological improvements such as extrusion process improvements 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 manufacturing process. The cable includes a protective outer layer, an insulating intermediate layer, and a conductor inner layer arranged sequentially from the outside to the inside. The material of the protective outer layer, calculated by weight, includes: 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 parts of light stabilizer. The cable includes an inner conductive layer, an intermediate 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 low smoke, halogen-free, and good flame-retardant effect.

[0004] However, the above-mentioned patent only describes the preparation of flame-retardant fillers through talc surface modification, pyrimidine derivative grafting, and boric acid reaction, and uses the flame-retardant fillers as additives for the protective outer layer to improve the flame-retardant and wear-resistant properties 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. Furthermore, the talc-based flame-retardant filler is prone to peeling off under mechanical stress, reducing the flame-retardant durability. Silicon-based flame retardants have poor compatibility with the matrix and are prone to agglomeration, which weakens the mechanical properties. As a result, the wear resistance of the cable needs to be further improved.

[0005] Moreover, the flame retardant system relies on physical filling, and talc modification only provides physical barrier. It lacks efficient char formation or gas phase smoke suppression mechanism, resulting in limited flame retardant effect. There is no strong chemical bond between the flame retardant filler and the matrix, and it is prone to failure after long-term use. Therefore, the flame retardant performance of this cable needs to be further improved. Summary of the Invention

[0006] The purpose of this invention is to provide a halogen-free flame-retardant wear-resistant cable and its preparation method, in order to solve the technical problem that the wear resistance and flame-retardant properties of cables in the prior art need to be further improved.

[0007] The objective of this invention can be achieved through the following technical solution: a method for preparing a halogen-free flame-retardant wear-resistant cable, comprising the following steps:

[0008] S1. Several copper wires are twisted together and then coated with polyvinylidene fluoride to form a conductor layer.

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

[0010] S3. Add flame-retardant and wear-resistant material to an extruder, extrude it to cover the surface of the shielding layer, and obtain the sheath layer after natural curing.

[0011] Further, in step S1, the diameter of the copper wire is 0.4-0.5 mm, and the coating thickness of polyvinylidene chloride is 0.8 mm; in step S2, the thickness of the copper strip is 0.8-0.9 mm, and it is wrapped in two layers; in step S3, 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.

[0012] Furthermore, the plasticizer is one or both of propylene glycol and ethylene glycol; the stabilizer is one or both of lead tribasic 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 inlet to the discharge outlet are 170℃, 175℃, 175℃, 180℃, 185℃, 190℃, 190℃, and 200℃, respectively. The main engine speed of the twin-screw extruder is 80-120 rpm, the pressure is 100-150 bar, and the extrusion thickness is 1.2-1.6 mm.

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

[0015] A1. Polyethylene glycol, 5-aminoresorcinol, N,N-dimethylformamide and dibutyltin dilaurate are added to a reaction vessel and stirred. The temperature of the reaction vessel is raised to 50-60℃. Dimethylsilane diisocyanate is added dropwise to the reaction vessel and the reaction is maintained at this temperature for 40-60 min. A flame retardant chain extender is added to the reaction vessel and the reaction is maintained at this temperature for 20-30 min. An inorganic end-capping agent is added to the reaction vessel and the reaction is maintained at this temperature for 30-40 min. The modified polyurethane is obtained after post-treatment.

[0016] A2. Modified polyurethane, triethylamine, and N,N-dimethylformamide were added to a low-temperature reactor. After nitrogen protection, the reactor temperature was lowered to 0-5℃. Diphenyl chlorophosphate was then added dropwise to the reactor. The addition was kept at the temperature for 2-3 hours. The temperature of the low-temperature reactor was then raised to room temperature, and the reaction was continued at room temperature for 10-12 hours. The composite polyurethane was then obtained after post-treatment.

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

[0018]

[0019] The reaction principle for preparing composite polyurethane is as follows: under heating and catalyst promotion, the isocyanate groups on dimethyl diisocyanate react with the hydroxyl groups on polyethylene glycol and 5-aminoresorcinol to form a long chain structure with isocyanate groups at the end. The hydroxyl groups on the flame retardant chain extender react with the attenuated isocyanate groups to form a spatial chain segment structure. Finally, the composite polyurethane is obtained by end-capping with the amino groups on the inorganic end-capping agent.

[0020] Further, in step A1, the ratio of polyethylene glycol, 5-aminoresorcinol, N,N-dimethylformamide, dibutyltin dilaurate, dimethylsilane 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. The post-treatment includes: after the reaction is completed, after the temperature of the reaction vessel drops to room temperature, the reaction solution is transferred to a rotary evaporator with a salt bath temperature of 80-100℃, and distilled under reduced pressure until no liquid is collected, to obtain modified polyurethane;

[0021] Furthermore, in step A2, the ratio of modified polyurethane, triethylamine, N,N-dimethylformamide, and diphenyl chlorophosphate is 6-7g:1-2g:25-30mL:2-3g. The post-treatment includes: after the reaction is completed, after the temperature of the reaction vessel drops to room temperature, the reaction solution is transferred to a rotary evaporator with a salt bath temperature of 80-100℃, and distilled under reduced pressure until no liquid is collected, thus obtaining the composite polyurethane.

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

[0023] B1. Add 4,5-diaminophenyl-1,2-diol, imidazole and dichloromethane to a reaction vessel, stir at room temperature for 10-15 min, then add trimethylchlorosilane to the reaction vessel, stir at room temperature for 10-12 h, and then perform post-treatment to obtain the modified monomer.

[0024] B2. Add the modified monomer, sodium bicarbonate and dimethylformamide to the reaction vessel. After continuously adding phenylphosphonic dichloride dropwise to the reaction vessel at room temperature for 2-3 hours, raise the temperature of the reaction vessel to 100-120℃ and keep the reaction at this temperature for 10-12 hours. The flame retardant chain extender precursor is obtained after post-treatment.

[0025] B3. Add the flame retardant chain extender precursor and anhydrous ethanol to the reaction vessel, stir at room temperature for 10-15 min, then add 0.2-0.3 mol / L hydrochloric acid aqueous solution dropwise to the reaction vessel, and keep the reaction at the temperature for 20-24 h. The flame retardant chain extender is obtained after post-treatment.

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

[0027]

[0028] The reaction principle for preparing flame-retardant chain extenders is as follows: the hydroxyl group on 4,5-diaminobenzene-1,2-diphenol, activated by imidazole, acts as a nucleophile to attack trimethylchlorosilane. The chlorine group is substituted as a leaving group to form a silicon-oxygen bond, yielding a modified monomer. Under alkaline conditions, the deprotonation of the amino group of the modified monomer is promoted, enhancing its nucleophilicity and promoting its electrophilic substitution reaction with the phosphoric chlorine group on phenylphosphonic dichloride. Finally, a long-chain flame-retardant chain extender precursor is prepared. Finally, the silane structure is removed by catalysis under acidic conditions in anhydrous ethanol, and the flame-retardant chain extender is obtained.

[0029] Further, in step B1, the ratio of 4,5-diaminophenyl-1,2-diol, imidazole, dichloromethane, and trimethylchlorosilane is 3-4g:0.3-0.5g:30-36mL:5-6g. The post-treatment includes: after the reaction is completed, after the temperature of the reaction vessel drops to room temperature, the reaction solution is transferred to a rotary evaporator with a salt bath temperature of 80-100℃, and distilled under reduced pressure until no liquid is collected to obtain the modified monomer.

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

[0031] Furthermore, in step B3, the 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. The post-treatment includes: after the reaction is completed, after the temperature of the reaction vessel drops to room temperature, the reaction solution is transferred to a rotary evaporator with a salt bath temperature of 80-100℃, and distilled under reduced pressure until no liquid is collected, thus obtaining the flame retardant chain extender.

[0032] Furthermore, the preparation method of the inorganic end-capping agent includes the following steps:

[0033] C1. Add aluminum chloride hexahydrate and deionized water to a high-pressure reactor. Stir at room temperature for 5-8 minutes, then add sodium hydroxide powder to the reactor. Continue adding for 2 hours, then add magnesium sulfate to the reactor. Transfer the high-pressure reactor to an oven, raise the oven temperature to 180-200℃, and keep it at that temperature for 6-8 hours. Post-processing yields nano whiskers.

[0034] C2. Add nanocrystals and deionized water to the reaction vessel and stir. Adjust the pH of the reaction system to 3-4 using 98.0wt% sulfuric acid aqueous solution, stir at room temperature for 30-40 min, and then perform post-processing to obtain etched nanocrystals.

[0035] C3. Add etched nanocrystals, anhydrous ethanol and deionized water to the reaction vessel and stir. Raise the temperature of the reaction vessel to 40-60℃, and adjust the pH of the reaction system to 8-9 using a saturated sodium hydroxide aqueous solution. Then add 4-aminobutyltriethoxysilane to the reaction vessel and keep the reaction at this temperature for 40-60 min. The inorganic end-capping agent is obtained after post-treatment.

[0036] The reaction principle for preparing inorganic end-capping agents is as follows: under alkaline and hydrothermal conditions, aluminum chloride hexahydrate and magnesium sulfate hydrolyze to produce nano-whisker structures. After acid etching, the siloxy groups on 4-aminobutyltriethoxysilane hydrolyze to produce silanol structures, which react with the active functional groups on the etched nano-whiskers to finally prepare the inorganic end-capping agent.

[0037] Further, in step C1, the ratio of aluminum chloride hexahydrate, deionized water, sodium hydroxide powder, and magnesium sulfate is 2-3g:100mL:4-5g:1-2g. The post-treatment includes: after the reaction is completed, after the temperature of the reaction vessel drops to room temperature, the reaction solution is filtered to collect the filter cake. The filter cake is washed 3-5 times with anhydrous ethanol and deionized water. The filter cake is then transferred to a drying oven at 60℃ and vacuum dried to constant weight to obtain nano whiskers.

[0038] Furthermore, in step C2, the ratio of nanocrystals to deionized water is 3-4g:40-50mL. The post-treatment includes: after the reaction is completed, after the temperature of the reaction vessel drops to room temperature, the reaction solution is filtered to collect the filter cake. The filter cake is washed 3-5 times with anhydrous ethanol and deionized water. The filter cake is then transferred to a drying oven at 60℃ and vacuum dried to constant weight to obtain etched nanocrystals.

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

[0040] The present invention also proposes a halogen-free flame-retardant wear-resistant cable, which is prepared by 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 this invention is formed by the reaction of dimethyl diisocyanate, polyethylene glycol, and 5-aminoresorcinol to form a long-chain structure, which is then crosslinked with a flame-retardant chain extender and an inorganic end-capping agent to construct a spatial network structure with alternating soft and hard phases, possessing both flexibility and high strength. The inorganic end-capping agent is generated by hydrolyzing aluminum chloride hexahydrate and magnesium sulfate to form nano-whiskers, which are strongly bonded to the matrix after silane modification, enhancing surface hardness and wear resistance, while dispersing external forces and reducing wear. The flame-retardant chain extender improves crosslinking density and heat resistance through a long-chain structure containing silicon-oxygen bonds and phosphonoyl groups, reducing 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 enhances wear resistance. This multi-component synergistic effect forms a high-toughness, high-hardness, and wear-resistant sheath layer, enabling the cable to exhibit excellent durability under friction and mechanical stress, significantly extending its service life.

[0043] 2. The composite polyurethane backbone prepared by this invention is formed from dimethylsilane diisocyanate, polyethylene glycol, and 5-aminoresorcinol, combining flexibility and stiffness. It achieves high tensile strength while maintaining ductility. The backbone is cross-linked by a flame-retardant chain extender containing siloxane and phosphine groups, which increases network density, disperses stress to improve strength, and stabilizes the chain to prevent tensile-induced fracture. Nanoscale whiskers obtained from hydrolyzed aluminum chloride hexahydrate and magnesium sulfate are added as a supplement. They are functionalized with 4-aminobutyltriethoxysilane and anchored to the matrix through silanol-derived covalent bonds. These rigid fillers improve tensile strength by transferring stress and improve toughness by hindering crack propagation. The silane chemistry in both components ensures strong interfacial bonding, prevents phase separation, and optimizes load transfer. The interaction of the flexible matrix, rigid whisker reinforcement, and strong interface creates a material that performs well in bearing tensile force and absorbing energy, thus providing a wear-resistant cable sheath with excellent mechanical properties.

[0044] 3. The composite polyurethane backbone prepared by this invention is formed from dimethylsilane diisocyanate, polyethylene glycol, and 5-aminoresorcinol, combining flexibility and stiffness. It achieves high tensile strength 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 tensile-induced fracture. Nanoscale whiskers obtained from hydrolyzed aluminum chloride hexahydrate and magnesium sulfate are used as a supplement. They are functionalized with 4-aminobutyltriethoxysilane and anchored to the matrix through silanol-derived covalent bonds. These rigid fillers improve tensile strength by transferring stress and improve toughness by hindering crack propagation. The silane chemical composition in the two components ensures strong interfacial bonding, prevents phase separation, and optimizes load transfer. The interaction between the flexible matrix, rigid whisker reinforcement, and strong interface results in a tensile-resistant and wear-resistant cable. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a three-dimensional structural diagram of the entire invention.

[0047] In the diagram: 100, conductor layer; 200, shielding layer; 300, sheath layer. Detailed Implementation

[0048] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

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

[0050] The polyethylene glycol used in this invention was purchased from Nantong Yuyuan New Material Technology Co., Ltd., and its product number is PEG800.

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

[0052] Example 1

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

[0054] Step I: Preparation of nanocrystals

[0055] Weigh out 60.0 g of aluminum chloride hexahydrate and 3000.0 mL of deionized water and add them to a high-pressure reactor. After stirring at room temperature for 5 min, add 120.0 g of sodium hydroxide powder to the reactor and continue adding for 2 h. Then add 30.0 g of magnesium sulfate to the reactor and transfer the high-pressure reactor to an oven. Raise the oven temperature to 180 °C and keep it at that temperature for 6 h. After the reaction is complete, wait for the reactor temperature to drop to room temperature, filter the reaction liquid and collect the filter cake. Wash the filter cake three times with anhydrous ethanol and deionized water. Transfer the filter cake to a drying oven at 60 °C and vacuum dry it to constant weight to obtain nano whiskers.

[0056] Step II: Preparation of etched nanocrystals

[0057] Weigh 60.0g of nano whiskers and 800.0mL of deionized water and add them to the reaction vessel. Stir the mixture and adjust the pH of the reaction system to 3 using 98.0wt% sulfuric acid aqueous solution. Stir the mixture at room temperature for 30min. After the reaction is complete, wait for the temperature of the reaction vessel to drop to room temperature, filter the reaction solution and collect the filter cake. Wash the filter cake three times with anhydrous ethanol and deionized water. Transfer the filter cake to a drying oven at 60℃ and vacuum dry it to constant weight to obtain etched nano whiskers.

[0058] Step III: Preparation of Inorganic End-Capping Agent

[0059] Weigh out 42.0 g of etched nano whiskers, 210.0 mL of anhydrous ethanol, and 120.0 mL of deionized water and add them to the reaction vessel. Stir the mixture and raise the temperature of the reaction vessel to 40°C. Adjust the pH of the reaction system to 8 using a saturated sodium hydroxide aqueous solution. Then add 20.0 g of 4-aminobutyltriethoxysilane to the reaction vessel and keep it at this temperature for 40 min. After the reaction is complete, wait for the temperature of the reaction vessel to drop to room temperature. Filter the reaction solution and collect the filter cake. Wash the filter cake three times with anhydrous ethanol and deionized water. Transfer the filter cake to a drying oven at 60°C and vacuum dry it to constant weight to obtain the inorganic end-capping agent.

[0060] Example 2

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

[0062] Step I: Preparation of nanocrystals

[0063] Weigh out 90.0 g of aluminum chloride hexahydrate and 3000.0 mL of deionized water and add them to a high-pressure reactor. After stirring at room temperature for 8 min, add 150.0 g of sodium hydroxide powder to the reactor and continue adding for 2 h. Then add 60.0 g of magnesium sulfate to the reactor and transfer the high-pressure reactor to an oven. Raise the oven temperature to 200 °C and keep it at that temperature for 8 h. After the reaction is complete, wait for the reactor temperature to drop to room temperature, filter the reaction liquid and collect the filter cake. Wash the filter cake 5 times with anhydrous ethanol and deionized water. Transfer the filter cake to a drying oven at 60 °C and vacuum dry it to constant weight to obtain nano whiskers.

[0064] Step II: Preparation of etched nanocrystals

[0065] Weigh 80.0g of nano whiskers and 1000.0mL of deionized water and add them to the reaction vessel. After stirring, adjust the pH of the reaction system to 4 using 98.0wt% sulfuric acid aqueous solution and stir at room temperature for 40min. After the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, filter the reaction solution and collect the filter cake. Wash the filter cake 5 times with anhydrous ethanol and deionized water, and then transfer the filter cake to a drying oven at 60℃ and vacuum dry it to constant weight to obtain etched nano whiskers.

[0066] Step III: Preparation of Inorganic End-Capping Agent

[0067] Weigh out 60.0g of etched nanocrystals, 360.0mL of anhydrous ethanol and 240.0mL of deionized water and add them to the reaction vessel. Stir the mixture and raise the temperature of the reaction vessel to 40℃. After adjusting the pH of the reaction system to 9 with saturated sodium hydroxide aqueous solution, add 40.0g of 4-aminobutyltriethoxysilane to the reaction vessel and keep it at this temperature for 40min. After the reaction is complete, wait for the temperature of the reaction vessel to drop to room temperature, filter the reaction solution and collect the filter cake. Wash the filter cake 5 times with anhydrous ethanol and deionized water, and then transfer the filter cake to a drying oven at 60℃ and vacuum dry it to constant weight to obtain the inorganic end-capping agent.

[0068] Example 3

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

[0070] Step I: Preparation of nanocrystals

[0071] Weigh out 75.0 g of aluminum chloride hexahydrate and 3000.0 mL of deionized water and add them to a high-pressure reactor. After stirring at room temperature for 8 min, add 150.0 g of sodium hydroxide powder to the reactor and continue adding for 2 h. Then add 45.0 g of magnesium sulfate to the reactor and transfer the high-pressure reactor to an oven. Raise the oven temperature to 180 °C and keep it at that temperature for 7 h. After the reaction is complete, wait for the reactor temperature to drop to room temperature, filter the reaction liquid and collect the filter cake. Wash the filter cake 4 times with anhydrous ethanol and deionized water. Transfer the filter cake to a drying oven at 60 °C and vacuum dry it to constant weight to obtain nano whiskers.

[0072] Step II: Preparation of etched nanocrystals

[0073] Weigh 72.0 g of nano whiskers and 800.0 mL of deionized water and add them to the reaction vessel. After stirring, adjust the pH of the reaction system to 3 using 98.0 wt% sulfuric acid aqueous solution and stir at room temperature for 36 min. After the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, filter the reaction solution and collect the filter cake. Wash the filter cake 4 times with anhydrous ethanol and deionized water, and then transfer the filter cake to a drying oven at 60 ℃ and vacuum dry it to constant weight to obtain etched nano whiskers.

[0074] Step III: Preparation of Inorganic End-Capping Agent

[0075] Weigh out 50.0g of etched nanocrystals, 240.0mL of anhydrous ethanol and 160.0mL of deionized water and add them to the reaction vessel. Stir the mixture and raise the temperature of the reaction vessel to 50℃. After adjusting the pH of the reaction system to 9 with saturated sodium hydroxide aqueous solution, add 30.0g of 4-aminobutyltriethoxysilane to the reaction vessel and keep it at this temperature for 50min. After the reaction is complete, wait for the temperature of the reaction vessel to drop to room temperature, filter the reaction solution and collect the filter cake. Wash the filter cake four times with anhydrous ethanol and deionized water, and then transfer the filter cake to a drying oven at 60℃ and vacuum dry it to constant weight to obtain the inorganic end-capping agent.

[0076] Example 4

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

[0078] Step ①: Preparation of modified monomers

[0079] Weigh out 30.0 g of 4,5-diaminobenzene-1,2-diol, 3.0 g of imidazole, and 300.0 mL of dichloromethane and add them to a reaction vessel. Stir at room temperature for 10 min, then add 50.0 g of trimethylchlorosilane to the reaction vessel and stir at room temperature for 10 h. After the reaction is complete, wait for the temperature of the reaction vessel to drop to room temperature, then transfer the reaction solution to a rotary evaporator with a salt bath temperature of 80 °C and distill under reduced pressure until no liquid is collected to obtain the modified monomer.

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

[0081] Weigh out 40.0g of modified monomer, 3.0g of sodium bicarbonate and 300.0mL of dimethylformamide and add them to the reaction vessel. 20.0g of phenylphosphonic dichloride is continuously added dropwise to the reaction vessel at room temperature for 2 hours. Then, the temperature of the reaction vessel is raised to 100℃ and kept at this temperature for 10 hours. After the reaction is completed, the temperature of the reaction vessel is lowered to room temperature. The reaction solution is then transferred to a rotary evaporator with a salt bath temperature of 80℃ and distilled under reduced pressure until no liquid is collected, thus obtaining the flame retardant chain extender precursor.

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

[0083] Weigh 30.0 g of flame retardant chain extender precursor and 200.0 mL of anhydrous ethanol and add them to a reaction vessel. Stir at room temperature for 15 min, then add 20.0 mL of 0.2 mol / L hydrochloric acid aqueous solution dropwise to the reaction vessel and keep it at the temperature for 20 h. After the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, then transfer the reaction solution to a rotary evaporator with a salt bath temperature of 80 °C and distill under reduced pressure until no liquid is collected to obtain the flame retardant chain extender.

[0084] Example 5

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

[0086] Step ①: Preparation of modified monomers

[0087] Weigh out 40.0 g of 4,5-diaminobenzene-1,2-diol, 5.0 g of imidazole and 360.0 mL of dichloromethane and add them to the reaction vessel. Stir at room temperature for 15 min, then add 60.0 g of trimethylchlorosilane to the reaction vessel and stir at room temperature for 12 h. After the reaction is complete, wait for the temperature of the reaction vessel to drop to room temperature, then transfer the reaction solution to a rotary evaporator with a salt bath temperature of 100 °C and distill under reduced pressure until no liquid is collected to obtain the modified monomer.

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

[0089] Weigh out 50.0g of modified monomer, 5.0g of sodium bicarbonate and 360.0mL of dimethylformamide and add them to the reaction vessel. Continuously add 30.0g of phenylphosphonic dichloride to the reaction vessel at room temperature for 3h. Then raise the temperature of the reaction vessel to 120℃ and keep it at this temperature for 12h. After the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, and then transfer the reaction solution to a rotary evaporator with a salt bath temperature of 100℃. Distill under reduced pressure until no liquid is collected to obtain the flame retardant chain extender precursor.

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

[0091] Weigh 40.0 g of flame retardant chain extender precursor and 240.0 mL of anhydrous ethanol and add them to a reaction vessel. Stir at room temperature for 15 min, then add 30.0 mL of 0.3 mol / L hydrochloric acid aqueous solution dropwise to the reaction vessel and keep it at the temperature for 24 h. After the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, then transfer the reaction solution to a rotary evaporator with a salt bath temperature of 100 °C and distill under reduced pressure until no liquid is collected to obtain the flame retardant chain extender.

[0092] Example 6

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

[0094] Step ①: Preparation of modified monomers

[0095] Weigh out 36.0 g of 4,5-diaminobenzene-1,2-diol, 4.0 g of imidazole and 320.0 mL of dichloromethane and add them to the reaction vessel. After stirring at room temperature for 12 min, add 54.0 g of trimethylchlorosilane to the reaction vessel and stir at room temperature for 12 h. After the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, then transfer the reaction solution to a rotary evaporator with a salt bath temperature of 90 °C and distill under reduced pressure until no liquid is collected to obtain the modified monomer.

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

[0097] Weigh out 48.0g of modified monomer, 4.0g of sodium bicarbonate and 320.0mL of dimethylformamide and add them to the reaction vessel. 24.0g of phenylphosphonic dichloride is continuously added dropwise to the reaction vessel at room temperature for 2 hours. Then, the temperature of the reaction vessel is raised to 120℃ and kept at this temperature for 12 hours. After the reaction is completed, the temperature of the reaction vessel is lowered to room temperature. The reaction solution is then transferred to a rotary evaporator with a salt bath temperature of 90℃ and distilled under reduced pressure until no liquid is collected, thus obtaining the flame retardant chain extender precursor.

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

[0099] Weigh 36.0 g of flame retardant chain extender precursor and 210.0 mL of anhydrous ethanol and add them to a reaction vessel. Stir at room temperature for 12 min, then add 24.0 mL of 0.3 mol / L hydrochloric acid aqueous solution dropwise to the reaction vessel and keep it at the temperature for 21 h. After the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, then transfer the reaction solution to a rotary evaporator with a salt bath temperature of 90 °C and distill under reduced pressure until no liquid is collected to obtain the flame retardant chain extender.

[0100] Example 7

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

[0102] Step 1: Preparation of modified polyurethane

[0103] Weigh out 36.0g of polyethylene glycol, 27.0g of 5-aminoresorcinol, 400.0mL of N,N-dimethylformamide and 3.0g of dibutyltin dilaurate and add them to a reaction vessel. Stir the mixture and raise the temperature of the reaction vessel to 50°C. Add 54.0g of dimethylsilane diisocyanate dropwise to the reaction vessel and keep it at this temperature for 40min. Add 20.0g of the flame retardant chain extender prepared in Example 4 to the reaction vessel and keep it at this temperature for 20min. Add 40.0g of the inorganic end-capping agent prepared in Example 1 to the reaction vessel and keep it at this temperature for 30min. After the reaction is complete, wait for the temperature of the reaction vessel to drop to room temperature and then transfer the reaction solution to a rotary evaporator with a salt bath temperature of 80°C. Distill under reduced pressure until no liquid is collected to obtain modified polyurethane.

[0104] Step 2: Preparation of composite polyurethane

[0105] Weigh out 60.0g of modified polyurethane, 10.0g of triethylamine and 250.0mL of N,N-dimethylformamide and add them to a low-temperature reactor. After purging with nitrogen, lower the reactor temperature to 5℃, then add 20.0g of diphenyl chlorophosphate dropwise. Keep the temperature constant for 2-3 hours, then raise the reactor temperature to room temperature and continue the reaction at room temperature for 10 hours. After the reaction is complete, wait for the reactor temperature to drop to room temperature, then transfer the reaction solution to a rotary evaporator with a salt bath temperature of 100℃ and distill under reduced pressure until no liquid is collected, thus obtaining the composite polyurethane.

[0106] Example 8

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

[0108] Step 1: Preparation of modified polyurethane

[0109] Weigh out 42.0g of polyethylene glycol, 32.0g of 5-aminoresorcinol, 500.0mL of N,N-dimethylformamide, and 5.0g of dibutyltin dilaurate and add them to a reaction vessel. Stir the mixture and raise the temperature of the reaction vessel to 60°C. Add 64.0g of dimethylsilane diisocyanate dropwise to the reaction vessel and keep it at this temperature for 60min. Add 30.0g of the flame retardant chain extender prepared in Example 5 to the reaction vessel and keep it at this temperature for 30min. Add 60.0g of the inorganic end-capping agent prepared in Example 2 to the reaction vessel and keep it at this temperature for 40min. After the reaction is complete, wait for the temperature of the reaction vessel to drop to room temperature, then transfer the reaction solution to a rotary evaporator with a salt bath temperature of 100°C and distill under reduced pressure until no liquid is collected, thus obtaining modified polyurethane.

[0110] Step 2: Preparation of composite polyurethane

[0111] Weigh out 70.0g of modified polyurethane, 20.0g of triethylamine and 300.0mL of N,N-dimethylformamide and add them to a low-temperature reactor. After purging with nitrogen, the reactor temperature is lowered to 0℃. Then, 30.0g of diphenyl chlorophosphate is added dropwise to the reactor. After maintaining the temperature for 3 hours, the reactor temperature is raised to room temperature and the reaction continues for 12 hours at room temperature. After the reaction is completed, the reactor temperature is lowered to room temperature, and the reaction solution is transferred to a rotary evaporator with a salt bath temperature of 100℃. The solution is then distilled under reduced pressure until no liquid is collected, thus obtaining the composite polyurethane.

[0112] Example 9

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

[0114] Step 1: Preparation of modified polyurethane

[0115] Weigh out 40.0g polyethylene glycol, 30.0g 5-aminoresorcinol, 480.0mL N,N-dimethylformamide, and 4.0g dibutyltin dilaurate and add them to a reaction vessel. Stir the mixture and raise the temperature of the reaction vessel to 54℃. Add 60.0g dimethylsilane diisocyanate dropwise to the reaction vessel and keep it at this temperature for 50min. Add 25.0g of the flame retardant chain extender prepared in Example 6 to the reaction vessel and keep it at this temperature for 25min. Add 50.0g of the inorganic end-capping agent prepared in Example 3 to the reaction vessel and keep it at this temperature for 36min. After the reaction is complete, wait for the temperature of the reaction vessel to drop to room temperature, then transfer the reaction solution to a rotary evaporator with a salt bath temperature of 90℃ and distill under reduced pressure until no liquid is collected, thus obtaining modified polyurethane.

[0116] Step 2: Preparation of composite polyurethane

[0117] Weigh out 64.0 g of modified polyurethane, 16.0 g of triethylamine and 300.0 mL of N,N-dimethylformamide and add them to a low-temperature reactor. After purging with nitrogen for protection, the reactor temperature is lowered to 3°C. Then, 24.0 g of diphenyl chlorophosphate is added dropwise to the reactor. After maintaining the temperature for 2 hours, the reactor temperature is raised to room temperature and the reaction continues for 12 hours at room temperature. After the reaction is completed, the reactor temperature is lowered to room temperature, and the reaction solution is transferred to a rotary evaporator with a salt bath temperature of 90°C. The solution is then distilled under reduced pressure until no liquid is collected, yielding the composite polyurethane.

[0118] Example 10

[0119] This embodiment provides a method for preparing a halogen-free flame-retardant wear-resistant cable, including 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 a 0.8 mm thick polyvinylidene fluoride layer to form a conductor layer 100.

[0122] Step 2: Prepare the shielding layer

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

[0124] Step 3: Prepare the sheath layer

[0125] Weigh out 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 an extruder. The temperatures of the eight temperature zones of the extruder from the feed port to 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 80 rpm and the pressure is 100 bar. The extruded material is coated on the surface of the shielding layer with an extrusion thickness of 1.2 mm. After natural curing, a sheath layer 300 is obtained.

[0126] Example 11

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

[0128] Step 1: Prepare the conductor layer

[0129] A conductor layer 100 is formed by stranding seven copper wires with a radius of 0.5 mm together and then covering the surface with a polyvinylidene fluoride layer with a thickness of 0.8 mm.

[0130] Step 2: Prepare the shielding layer

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

[0132] Step 3: Prepare the sheath layer

[0133] Weigh out 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 to an extruder. The temperatures of the eight temperature zones of the extruder from the feed port to 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 120 rpm and the pressure is 150 bar. The extruded material is coated on the surface of the shielding layer with an extrusion thickness of 1.6 mm. After natural curing, a sheath layer 300 is obtained.

[0134] Example 12

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

[0136] Step 1: Prepare the conductor layer

[0137] A conductor layer 100 is formed by stranding seven copper wires with a radius of 0.5 mm together and then covering the surface with a polyvinylidene fluoride layer with a thickness of 0.8 mm.

[0138] Step 2: Prepare the shielding layer

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

[0140] Step 3: Prepare the sheath layer

[0141] Weigh out 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 to an extruder. The temperatures of the eight temperature zones of the extruder from the feed port to 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 100 rpm and the pressure is 120 bar. The extruded material is coated on the surface of the shielding layer with an extrusion thickness of 1.5 mm. After natural curing, a 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 in the preparation process of the composite polyurethane used in step three. Flame retardant.

[0144] Comparative Example 2

[0145] The difference between this comparative example and Example 12 is that the flame retardant chain extender was omitted during the preparation of the composite polyurethane used in step three.

[0146] Comparative Example 3

[0147] The difference between this comparative example and Example 12 is that the inorganic end-capping agent was omitted during the preparation of the composite polyurethane used in step three.

[0148] Performance testing:

[0149] The volumetric wear of the abrasion-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 abrasion resistance of vulcanized rubber or thermoplastic rubber (rotary roller abrasion tester method)".

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

[0151] The tensile strength of the abrasion-resistant cables prepared in Examples 10-12 and Comparative Examples 1-3 was tested in accordance with standard XF 306.1-2007 "Flame-retardant and fire-resistant cables - Classification and requirements of plastic insulated flame-retardant and fire-resistant cables - 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 in accordance with the standard GB / T 32129-2015 "Halogen-free Low-smoke Flame-retardant Cable Material for Wires and Cables". The specific data are shown in Table 1.

[0153] Table 1 - Performance Test Data for Each Sample

[0154] Data Analysis:

[0155] Comparative analysis of the data in Table 1 reveals that the volumetric wear of the wear-resistant cable prepared by this invention is 28 mm. 3 The flame retardant rating is IA, the tensile strength is 24.3 MPa, and the flaming smoke density during combustion is 10⁴, while the extinguished smoke density during combustion is 5¹. All these data are superior to the comparative example. This indicates that:

[0156] The composite polyurethane prepared by this invention is formed by the reaction of dimethyl diisocyanate, polyethylene glycol, and 5-aminoresorcinol to form a long-chain structure, which is then crosslinked with a flame-retardant chain extender and an inorganic end-capping agent to construct a spatial network structure with alternating soft and hard phases, possessing both flexibility and high strength. The inorganic end-capping agent is generated by hydrolyzing aluminum chloride hexahydrate and magnesium sulfate to form nano whiskers, which are strongly bonded to the matrix after silane modification, enhancing surface hardness and wear resistance, while dispersing external forces and reducing wear. The flame-retardant chain extender improves crosslinking density and heat resistance through a long-chain structure containing silicon-oxygen bonds and phosphonoyl groups, reducing 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 enhances wear resistance. This multi-component synergistic effect forms a high-toughness, high-hardness, and wear-resistant sheath layer, enabling the cable to exhibit excellent durability under friction and mechanical stress, significantly extending its service life.

[0157] The composite polyurethane backbone prepared by this invention is formed from dimethylsilane diisocyanate, polyethylene glycol, and 5-aminoresorcinol, combining flexibility and stiffness. It achieves high tensile strength while maintaining ductility. The backbone is cross-linked by a flame-retardant chain extender containing siloxane and phosphine groups, which increases network density, disperses stress to improve strength, and stabilizes the chain to prevent tensile-induced fracture. Nanoscale whiskers obtained from hydrolyzed aluminum chloride hexahydrate and magnesium sulfate are added as a supplement. They are functionalized with 4-aminobutyltriethoxysilane and anchored to the matrix through silanol-derived covalent bonds. These rigid fillers improve tensile strength by transferring stress and improve toughness by hindering crack propagation. The silane chemical composition in both components ensures strong interfacial bonding, prevents phase separation, and optimizes load transfer. The interaction of the flexible matrix, rigid whisker reinforcement, and strong interface results in a tensile-resistant and abrasion-resistant cable.

[0158] The flame retardant chain extender prepared by this invention contains phosphorus and siloxy groups derived from 4,5-diaminophenyl-1,2-diol and phenylphosphonic acid dichloride. During combustion, it promotes the dehydration of organic materials, forming a thermally stable carbonaceous layer. Silicon decomposes into silicon dioxide, enhancing the carbide to block heat and oxygen, thereby suppressing flames and smoke. Nanoscale whiskers made from hydrolyzed aluminum chloride hexahydrate and magnesium sulfate are used as a supplement, and functionalized with 4-aminobutyltriethoxysilane, enhancing thermal stability. The whiskers are bonded through silanol groups, providing a bond to the carbide. The silica structure further reduces the emission of flammable gases and smoke. The polyurethane matrix is ​​cross-linked with a chain extender and end-capped 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. Finally, through phosphorus-driven carbonization, silicon-reinforced silica barrier layer, thermally stable whiskers and robust matrix, the cable is given excellent flame retardancy and low smoke density, thus significantly improving the flame retardant performance of the wear-resistant cable.

[0159] The final explanation is that under alkaline and hydrothermal conditions, aluminum chloride hexahydrate and magnesium sulfate hydrolyze to produce nanocrystal whisker structures. After acid etching, the siloxy groups on 4-aminobutyltriethoxysilane hydrolyze to produce silanol structures, which react with the active functional groups on the etched nanocrystal whiskers to finally prepare an inorganic end-capping agent. The hydroxyl groups on 4,5-diaminobenzene-1,2-diphenol, activated by imidazole, act as nucleophiles to attack trimethylchlorosilane, where the chlorine groups are substituted as leaving groups to form siloxane bonds, yielding a modified monomer. Under alkaline conditions, this modified monomer undergoes an electrophilic substitution reaction with the phosphoric acid chlorine groups on phenylphosphonodichlorosilane to finally prepare a long-chain flame retardant chain extender precursor. The process involves removing the silane structure in anhydrous ethanol under acidic conditions to prepare a flame-retardant chain extender. Under heating and catalysis, the isocyanate groups on dimethyl diisocyanate react with the hydroxyl groups on polyethylene glycol and 5-aminoresorcinol to form a long-chain structure capped with isocyanate groups. The reaction between the hydroxyl groups on the flame-retardant chain extender and the capped isocyanate groups forms a spatial segment structure. Finally, the amino groups on the inorganic capping agent are used to cap the chain, resulting in a composite polyurethane. The composite polyurethane is then used as the main material and mixed with auxiliary materials, and extruded and cured to obtain the sheath layer of the wear-resistant cable, ultimately yielding a high-performance wear-resistant cable.

[0160] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The 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, Includes the following steps: S1. Several copper wires are twisted together and then coated with polyvinylidene fluoride to form a conductor layer (100). S2. After the conductor layer (100) is pulled by the traction device, it is wrapped with copper strip to obtain the shielding layer (200). S3. Add flame-retardant and wear-resistant material to an extruder and extrude it to cover the surface of the shielding layer (200). After natural curing, a sheath layer (300) is obtained. The flame-retardant and wear-resistant material includes the following raw materials 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. The preparation method of the composite polyurethane includes the following steps: A1. Polyethylene glycol, 5-aminoresorcinol, N,N-dimethylformamide and dibutyltin dilaurate are added to a reaction vessel and stirred. The temperature of the reaction vessel is raised to 50-60℃. Dimethylsilane diisocyanate is added dropwise to the reaction vessel and the reaction is maintained at this temperature for 40-60 min. A flame retardant chain extender is added to the reaction vessel and the reaction is maintained at this temperature for 20-30 min. An inorganic end-capping agent is added to the reaction vessel and the reaction is maintained at this temperature for 30-40 min. The modified polyurethane is obtained after post-treatment. A2. Modified polyurethane, triethylamine and N,N-dimethylformamide are added to a low-temperature reactor. After nitrogen protection is introduced, the reactor temperature is lowered to 0-5℃. Diphenyl chlorophosphate is then added dropwise to the reactor. After keeping the temperature constant for 2-3 hours, the temperature of the low-temperature reactor is raised to room temperature. The reaction continues at room temperature for 10-12 hours. The composite polyurethane is then obtained after post-treatment. The preparation method of the flame retardant chain extender includes the following steps: B1. Add 4,5-diaminophenyl-1,2-diol, imidazole and dichloromethane to a reaction vessel, stir at room temperature for 10-15 min, then add trimethylchlorosilane to the reaction vessel, stir at room temperature for 10-12 h, and then perform post-treatment to obtain the modified monomer. B2. Add the modified monomer, sodium bicarbonate and dimethylformamide to the reaction vessel. After continuously adding phenylphosphonic dichloride dropwise to the reaction vessel at room temperature for 2-3 hours, raise the temperature of the reaction vessel to 100-120℃ and keep the reaction at this temperature for 10-12 hours. The flame retardant chain extender precursor is obtained after post-treatment. B3. Add the flame retardant chain extender precursor and anhydrous ethanol to the reaction vessel, stir at room temperature for 10-15 min, then add 0.2-0.3 mol / L hydrochloric acid aqueous solution dropwise to the reaction vessel, and keep the reaction at the temperature for 20-24 h. The flame retardant chain extender is obtained after post-treatment. The preparation method of the inorganic end-capping agent includes the following steps: C1. Add aluminum chloride hexahydrate and deionized water to a high-pressure reactor. Stir at room temperature for 5-8 minutes, then add sodium hydroxide powder to the reactor. Continue adding for 2 hours, then add magnesium sulfate to the reactor. Transfer the high-pressure reactor to an oven, raise the oven temperature to 180-200℃, and keep it at that temperature for 6-8 hours. Post-processing yields nano whiskers. C2. Add nanocrystals and deionized water to the reaction vessel and stir. Adjust the pH of the reaction system to 3-4 using 98.0wt% sulfuric acid aqueous solution, stir at room temperature for 30-40 min, and then process to obtain etched nanocrystals. C3. Add etched nanocrystals, anhydrous ethanol and deionized water to the reaction vessel and stir. Raise the temperature of the reaction vessel to 40-60℃, and adjust the pH of the reaction system to 8-9 using a saturated sodium hydroxide aqueous solution. Then add 4-aminobutyltriethoxysilane to the reaction vessel and keep the reaction at this temperature for 40-60 min. The inorganic end-capping agent is obtained after post-treatment.

2. The method for preparing a halogen-free flame-retardant wear-resistant cable according to claim 1, characterized in that, In step A1, the ratio of polyethylene glycol, 5-aminoresorcinol, N,N-dimethylformamide, dibutyltin dilaurate, dimethylsilane 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 ratio of modified polyurethane, triethylamine, N,N-dimethylformamide, and diphenyl chlorophosphate is 6-7g:1-2g:25-30mL:2-3g.

3. The method for preparing a halogen-free flame-retardant wear-resistant cable according to claim 1, characterized in that, In step B1, the ratio of the amounts 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; in step B2, the ratio of the amounts of the modified monomer, sodium bicarbonate, dimethylformamide, and phenylphosphonic dichloropropoxide is 4-5 g: 0.3-0.5 g: 30-36 mL: 2-3 g; in step B3, the ratio of the amount 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.

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

5. A halogen-free, flame-retardant, wear-resistant cable, characterized in that, The halogen-free flame-retardant wear-resistant cable is prepared using the preparation method of the halogen-free flame-retardant wear-resistant cable as described in any one of claims 1-4.

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