A high shielding effectiveness wear-resistant mesh wire and a preparation method thereof

Abstract

The application discloses a high-shielding-performance wear-resistant network cable and a preparation method thereof, and belongs to the technical field of network cable processing, and is used for solving the technical problem that the mechanical strength, wear resistance and electromagnetic shielding performance of network cable materials need to be further improved in the prior art, and specifically comprises a plurality of groups of wire cores and an outer sheath, the outer sheath comprises the following components in parts by weight: 70-80 parts of composite polyurethane, 25-35 parts of bisphenol A type epoxy resin, 20-26 parts of shielding particles and 3-5 parts of auxiliary additives. The application is characterized in that fluorine-modified polysiloxane is copolymerized with polytetrahydrofuran ether glycol to form composite polyurethane, and bisphenol A type epoxy resin is introduced to cooperatively cooperate with metal-doped graphene shielding particles coated by polydopamine to construct a flexible, dense and electromagnetic shielding outer sheath structure, so that the network cable simultaneously has excellent mechanical strength, wear resistance and electromagnetic shielding performance.

Description

Technical Field

[0001] This invention relates to the field of network cable processing technology, specifically to a wear-resistant network cable with high shielding effectiveness and its preparation method. Background Technology

[0002] With the rapid development of modern communication, computer networks and intelligent manufacturing technologies, higher requirements are placed on the performance of communication cables in terms of data transmission rate and stability. As an important medium for signal transmission, network cables not only need to have good mechanical protection in their outer sheath, but also need to effectively shield external interference signals in complex electromagnetic environments to ensure the integrity and stability of data transmission.

[0003] Currently, most network cables use metal materials to cover the wire core to improve their electromagnetic shielding performance. However, this operation has a high production cost. Although traditional polymer materials such as polyvinyl chloride, polyethylene, or polyurethane have certain mechanical strength and flexibility, their electromagnetic shielding performance is poor and they are difficult to resist radiation interference in complex electromagnetic environments. In order to improve the shielding effect of the material, conductive fillers such as metal powder, conductive carbon black, or graphene are usually added to the sheath material to improve the electromagnetic shielding performance. However, conductive fillers have poor compatibility with organic matrices and are prone to agglomeration, making it difficult to form a uniform and continuous conductive network. Poor dispersion of fillers will also weaken the flexibility and extensibility of the matrix. Furthermore, under long-term mechanical friction, the surface filler is prone to fall off, resulting in a decrease in shielding performance and a significant reduction in wear resistance.

[0004] In addition, to improve wear resistance, some technical solutions use hard inorganic particles or highly cross-linked resins to enhance the strength of the sheath. However, excessively high cross-linking density will restrict the movement of molecular chain segments, resulting in insufficient material toughness and reduced bending resistance, making it difficult to balance flexibility, wear resistance and shielding performance.

[0005] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a wear-resistant wire with high shielding effectiveness and its preparation method, in order to solve the technical problem that the mechanical strength, wear resistance and electromagnetic shielding performance of wire materials need to be further improved in the prior art.

[0007] The objective of this invention can be achieved through the following technical solution: a wear-resistant wire with high shielding efficiency, comprising several sets of wire cores and an outer sheath, wherein the outer sheath comprises the following components by weight: 70-80 parts of composite polyurethane, 25-35 parts of bisphenol A epoxy resin, 20-26 parts of shielding particles and 3-5 parts of auxiliary additives.

[0008] The shielding particles are metal-doped graphene coated with polydopamine.

[0009] The preparation method of the composite polyurethane is as follows: under an inert gas atmosphere, polytetrahydrofuran ether diol, fluorinated polysiloxane and toluene are mixed and stirred until the system is dissolved. The temperature of the reaction system is raised to 60-70℃. A catalyst and diphenylmethane 4,4ˊ-diisocyanate are added to the reaction system. The reaction is kept at this temperature for 60-80 min. Glycidyl ether is added to the reaction system. The reaction is kept at this temperature for 60-80 min. After post-treatment, the composite polyurethane is obtained.

[0010] The synthesis reaction equation for composite polyurethane is as follows:

[0011]

[0012] In the formula:

[0013] ;

[0014] ;

[0015] .

[0016] Furthermore, the ratio of polytetrahydrofuran ether diol, fluorinated polysiloxane, toluene, catalyst, and glycidyl is 10g:4-5g:30mL:0.1g:3g. The catalyst is dibutyltin dilaurate. The molar amount of diphenylmethane 4,4'-diisocyanate is 0.55-0.58 times the total molar amount of hydroxyl groups in polytetrahydrofuran ether diol and fluorinated polysiloxane. The post-treatment includes: after the reaction is complete, raising the temperature of the reaction system to 80-90℃, drawing a negative pressure to -0.1MPa, and removing low-boiling-point substances by vacuum evaporation to obtain composite polyurethane.

[0017] Furthermore, the preparation method of the fluorinated polysiloxane is as follows: dodecafluoroheptylpropylmethyldimethoxysilane, octamethylcyclotetrasiloxane, and sulfuric acid are mixed and stirred, the temperature of the reaction system is raised to 85-95℃, and the reaction is maintained at this temperature for 140-180 min. Then, (1,1,3,3-tetramethyl-1,3-disiloxanediyl)diethanol is added to the reaction system, and the reaction is maintained at this temperature for 80-100 min. After post-treatment, the fluorinated polysiloxane is obtained.

[0018] The synthesis reaction formula for fluorinated modified polysiloxanes is as follows:

[0019]

[0020] In the formula:

[0021]

[0022] Furthermore, the weight ratio of dodecafluoroheptylpropylmethyldimethoxysilane, octamethylcyclotetrasiloxane, sulfuric acid, and (1,1,3,3-tetramethyl-1,3-disiloxanediyl)diethanol is 3-4 g:8 g:2 mL:1.3-1.5 g, and the concentration of sulfuric acid is 75-85%. The post-treatment includes: after the reaction is complete, the temperature of the reaction system is lowered to room temperature, 2 wt% sodium carbonate aqueous solution is added to the reaction system to adjust the pH of the system to 7, the system is allowed to stand and separated, the upper organic matter is washed three times with purified water and then transferred to a rotary evaporator with a water bath temperature of 80-90℃, the pressure is reduced to -0.1 MPa, and the low-boiling substances are removed by vacuum evaporation to obtain fluorinated polysiloxane.

[0023] Furthermore, the preparation method of the shielding particles is as follows: metal-doped graphene and buffer solution are mixed, ultrasonically dispersed for 30-50 min, dopamine hydrochloride is added to the reaction system, and the reaction is carried out at room temperature for 6-8 h. After post-treatment, the shielding particles are obtained.

[0024] Furthermore, the ratio of the metal-doped graphene, buffer solution, and dopamine hydrochloride is 5g:200mL:1.3-1.5g. The post-processing includes: after the reaction is complete, filtration is performed, the filter cake is washed with purified water until neutral, then dried, and the filter cake is transferred to a drying oven at a temperature of 75-85℃ and dried to constant weight to obtain shielding particles.

[0025] Furthermore, the preparation method of metal-doped graphene is as follows: graphene oxide, nano-alumina and iron-based dispersion are mixed and ultrasonically dispersed for 50-70 min. Ammonia water is added to the reaction system to adjust the pH of the system to 10-11. The temperature of the reaction system is raised to 60-70℃ and kept at this temperature for 2-3 h. After post-treatment, metal-doped graphene is obtained.

[0026] Furthermore, the ratio of graphene oxide, nano-alumina, and iron-based dispersion is 2-3g:3-4g:100mL. The iron-based dispersion is composed of ferric chloride, ferrous chloride, deionized water, ethylene glycol, and sodium dodecyl sulfate in a ratio of 2g:1g:70-80mL:10-20mL:0.8-1.2g. The post-treatment includes: after the reaction is complete, the reaction system temperature is lowered to room temperature, filtered, the filter cake is washed with purified water until neutral, dried under vacuum, and the filter cake is transferred to a drying oven at a temperature of 60-70℃ and vacuum dried to constant weight to obtain metal-doped graphene.

[0027] This invention also proposes a method for preparing a wear-resistant wire with high shielding effectiveness, comprising the following steps:

[0028] S1. Arrange several groups of wire cores in parallel and twist them together to form a wire core bundle;

[0029] S2. After uniformly mixing the composite polyurethane, bisphenol A type epoxy resin, shielding particles and auxiliary additives, add them to a twin-screw extruder, melt mix for 2-3 minutes, extrude and coat the outside of the core bundle, cool and cure to form an outer sheath with a thickness of 0.7-0.8 mm.

[0030] Furthermore, the auxiliary additives are composed of plasticizer, antioxidant, dispersant, and lubricant in a weight ratio of 4:1:2:1. The plasticizer is phthalate, the antioxidant is either antioxidant 1010 or antioxidant 1076, the dispersant is stearate, and the lubricant is ethylene bisoleamide. The temperatures of the five temperature zones of the twin-screw extruder from the feed end to the discharge end are 155°C, 160°C, 160°C, 160°C, and 165°C, respectively.

[0031] The present invention has the following beneficial effects:

[0032] 1. This invention relates to a composite polyurethane prepared by copolymerizing fluorinated polysiloxane with polytetrahydrofuran ether diol. The flexible structure of the fluorosilicone segments improves the mobility of the molecular chains and the interfacial lubrication, while the polyether segments provide good elasticity, giving the outer sheath material high tensile strength and elongation at break. Bisphenol A type epoxy resin has excellent adhesion and mechanical properties. The combination of the flexible segments of the polyurethane and the rigid structure of the epoxy resin allows the material to effectively disperse stress and resist deformation under load. The polydopamine coating layer outside the shielding particles contains a large number of phenolic hydroxyl and amine groups, which significantly improves the interfacial compatibility between the shielding particles and the organic phase, avoids filler agglomeration, and can also bond with the epoxy groups on the polyurethane or epoxy resin molecules, further improving the tensile strength of the material.

[0033] 2. This invention also introduces polyether flexible segments and fluorinated siloxane segments into the composite polyurethane matrix. The flexible segments can reversibly stretch and orient under frictional stress, absorbing external forces at the molecular level and delaying the formation of microcracks. The phase crosslinking structure of the epoxy resin moderately constrains the segment movement at the molecular level, preventing large-scale plastic flow on the material surface under frictional loads and inhibiting surface fatigue deformation during wear. The Si-O-Si backbone has high flexibility and rotatability, which can disperse and alleviate localized stress concentration during friction, thereby inhibiting brittle fracture in the early stages of wear. The CF bond has extremely low surface energy, effectively reducing the adhesion and friction at the friction interface. The coefficient of friction makes the material surface more stable during frictional slippage, reducing adhesive wear. Fluorine has the characteristic of migrating to the surface during processing, forming a fluorine-rich lubricating layer. At the same time, the combination of fluorine segments and flexible siloxanes allows the surface friction energy to be released rapidly at the molecular level, delaying the cumulative effect of wear. Polydopamine-coated metal-doped graphene forms a rigid-flexible micro-skeleton structure inside the material. The high strength and interlayer slip characteristics of graphene enable it to bear part of the load during friction and also act as a solid lubricant, significantly enhancing the interfacial bonding force and preventing fillers from falling off during friction, thereby maintaining the stability and durability of the material structure.

[0034] 3. The shielding particles of this invention are core-shell structures formed by iron-doped graphene coated with polydopamine. At the molecular level, they construct a dual system of conductive network and magnetic centers. The conjugated π-electron system composed of sp² hybridized carbon atoms in the graphene sheets provides high-mobility electron channels. Under the influence of electromagnetic waves, electrons collectively oscillate in the conductive network, forming strong reflection losses. Simultaneously, magnetic iron oxide nanoparticles are doped into the graphene lattice or bonded to its surface, possessing high permeability, which can induce natural resonance, exchange resonance, and eddy current losses, thereby generating a magnetic loss effect on electromagnetic waves and improving the electromagnetic shielding performance of the material. The polydopamine coating layer itself is a weakly conductive organic phase, which is prone to dipole polarization and boundary polarization under high-frequency electric fields. Surface polarization enhances dielectric loss at the molecular level. The coating layer also improves the interfacial stability of the composite particles, preventing aggregation and further enhancing shielding effectiveness. Furthermore, the composite polyurethane and epoxy resin matrix form an interpenetrating network structure at the molecular level, providing flexible polyether segments and containing polar carbonyl, hydroxyl, and ether groups. These polar groups can undergo orientation polarization in an alternating electric field, generating additional dielectric loss. The introduction of fluorinated polysiloxane segments gives some C–F and Si–O bonds a high polarizability difference, which can form a micro-local electric dipole response in a high-frequency field, helping to dissipate electromagnetic wave energy. This allows the outer sheath to form a balanced energy transition region between the conductive layer and free space, thereby reducing interface reflection and enhancing absorption efficiency. Detailed Implementation

[0035] 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.

[0036] In this invention, the polytetrahydrofuran ether diol is PTMG1000, which is selected from commercially available materials from Shandong Suihua Biotechnology Co., Ltd.

[0037] In this invention, the nano-alumina is in flake form with a particle size of 80 nm and an effective component content of 99.9%, and is selected from commercially available materials from Lingshou County Bohan Mineral Products Co., Ltd.

[0038] In this invention, the graphene oxide has a diameter of 0.5-3 μm, a thickness of 0.55-1.2 nm, and an effective component content of 99%, and is selected from commercially available materials from Zhongke Leiming (Beijing) Technology Co., Ltd.

[0039] Example 1

[0040] This embodiment provides a method for preparing a wear-resistant wire with high shielding effectiveness, including the following steps:

[0041] Step 1: Preparation of fluorine-modified polysiloxane

[0042] Weigh out 30g of dodecafluoroheptylpropylmethyldimethoxysilane, 80g of octamethylcyclotetrasiloxane, and 20mL of 75wt% sulfuric acid and add them to a reaction flask. Stir the mixture and raise the temperature of the reaction flask to 85℃. Maintain the temperature for 140min. Add 13g of (1,1,3,3-tetramethyl-1,3-disiloxanediyl)diethanol to the reaction flask and maintain the temperature for 80min. Lower the temperature of the reaction flask to room temperature and add 2wt% sodium carbonate aqueous solution to adjust the pH of the system to 7. Allow the mixture to stand and separate the layers. Wash the upper organic matter three times with purified water and transfer it to a rotary evaporator with a water bath temperature of 80℃. Apply a negative pressure to -0.1MPa and remove low-boiling substances by vacuum evaporation to obtain fluorinated polysiloxane.

[0043] During the reaction, sulfuric acid protonates the oxygen atom of the silicon-oxygen bond in the octamethylcyclotetrasiloxane molecule, causing the Si–O bond to break polarized and generate a positively charged silicon center and a negatively charged oxygen anion. Under acidic conditions, the siloxane bond of dodecafluoroheptylpropylmethyldimethoxysilane hydrolyzes to generate silanol. The silanol condenses with the siloxane chain formed by the protonation and ring opening of octamethylcyclotetrasiloxane, introducing fluoroalkyl groups into the main chain to form a linear polydimethylsiloxane segment modified with fluoroalkyl groups. (1,1,3,3-tetramethyl-1,3-disiloxanediyl)dimethylethanol is used as a capping agent. The silanol generated by its hydrolysis reacts with the chain ends of the siloxane segments in the system, adjusting the molecular weight and generating terminal hydroxyl groups to prepare fluorinated polysiloxane.

[0044] Step 2: Preparation of composite polyurethane

[0045] Weigh 100g of polytetrahydrofuran ether glycol, 40g of fluorinated polysiloxane, and 300mL of toluene into an argon-protected reaction flask and stir until the system dissolves. Raise the temperature of the reaction flask to 60℃, add 1g of dibutyltin dilaurate catalyst to the reaction flask, and stir for 5min. Calculate the amount of diphenylmethane 4,4ˊ-diisocyanate to be added to the reaction flask based on 0.55 times the total molar amount of hydroxyl groups in the mixed system of polytetrahydrofuran ether glycol and fluorinated polysiloxane, and add it to the reaction flask. Maintain the temperature for 60min, add 30g of glycidyl ether to the reaction flask, maintain the temperature for 60min, raise the temperature of the reaction flask to 80℃, and apply a negative pressure to -0.1MPa to remove low-boiling-point substances by vacuum evaporation, thus obtaining the composite polyurethane.

[0046] During the reaction, the terminal hydroxyl groups of polytetrahydrofuran ether diol and fluorinated polysiloxane react with diphenylmethane 4,4ˊ-diisocyanate under the catalysis of a catalyst, generating a prepolymer with –NCO terminal groups. After the addition of glycidyl ether, the hydroxyl groups on the glycidyl ether molecule react with the isocyanate groups to generate epoxy end-capping modification, forming a block / interpenetrating composite polyurethane composed of flexible polyether segments, hydrophobic fluorosiloxane segments, and hard segments of diphenylmethane 4,4ˊ-diisocyanate.

[0047] Step 3: Preparation of shielding particles

[0048] Ferric chloride, ferrous chloride, deionized water, ethylene glycol and sodium dodecyl sulfate were mixed and stirred until the system was dissolved to obtain an iron-based dispersion.

[0049] Weigh out 20g of graphene oxide, 30g of nano-alumina and 1L of iron-based dispersion and add them to a reaction flask. Mix and ultrasonically disperse for 50min. Fix the reaction flask on an iron stand with mechanical stirring and stir. Add 6mol / L ammonia to the reaction flask to adjust the pH of the system to 10. Raise the temperature of the reaction flask to 60℃ and keep it at this temperature for 2h. Lower the temperature of the reaction flask to room temperature and filter. Wash the filter cake with purified water until neutral and then dry it. Transfer the filter cake to a drying oven at 60℃ and vacuum dry it to constant weight to obtain metal-doped graphene.

[0050] During the reaction, after adding graphene oxide and nano-alumina to the iron-based dispersion, the oxygen-containing functional groups on the surface of graphene oxide can combine with Fe³⁺ / Fe²⁺ through coordination or electrostatic interaction to form a surface complex layer. At the same time, under neutral conditions, the positive charge on the surface of the nano-alumina particles can further enhance the dispersion and fixation of iron ions, making the entire system more uniform. Ammonia water is added to adjust the pH of the system to alkaline, and a large amount of OH⁻ and Fe³⁺ / Fe²⁺ co-precipitate, generating Fe(OH)3 and Fe(OH)2 on the surface of graphene oxide or nano-alumina sheets. Then, in the system, they gradually dehydrate and condense to generate magnetic iron oxide nanoparticles that are uniformly loaded on the surface of graphene oxide, thus preparing metal-doped graphene.

[0051] Weigh out 50g of metal-doped graphene and 2L of buffer solution and add them to the reaction flask. Mix and sonicate for 30min. Fix the reaction flask on an iron stand with mechanical stirring and stir. Add 13g of dopamine hydrochloride to the reaction flask and react at room temperature for 6h. Filter and wash the filter cake with purified water until neutral. Dry the filter cake and transfer it to a drying oven at 75℃. Dry until constant weight to obtain shielding particles. The buffer solution is aminomethane buffer with a concentration of 0.1mol / L and pH=8.5.

[0052] In an alkaline buffer solution, dopamine undergoes auto-oxidation and auto-polymerization reactions, which proceed synergistically through redox, condensation, π–π interactions and coordination interactions, to form a polydopamine coating layer in situ deposited on the surface of metal-doped graphene, resulting in shielding particles with a core-shell structure.

[0053] Step 4: Prepare the network cable

[0054] Several groups of wire cores are arranged in parallel and twisted together to form a wire core bundle;

[0055] Diisobutyl phthalate, antioxidant 1010, zinc stearate, and ethylene dioleamide were mixed in a weight ratio of 4:1:2:1 to obtain an auxiliary additive.

[0056] Weigh out the following components by weight: 70 parts of composite polyurethane, 25 parts of bisphenol A epoxy resin, 20 parts of shielding particles, and 3 parts of auxiliary additives. Mix them evenly and add them to a twin-screw extruder. Set the temperatures of the five temperature zones of the twin-screw extruder from the feed end to the discharge end to 155℃, 160℃, 160℃, 160℃, and 165℃ respectively. Melt and mix for 2 minutes, then extrude to cover the outside of the core bundle. Cool down and cure to form an outer sheath with a thickness of 0.7mm, thus obtaining a sample of the network cable product.

[0057] Example 2

[0058] This embodiment provides a method for preparing a wear-resistant wire with high shielding effectiveness, including the following steps:

[0059] Step 1: Preparation of fluorine-modified polysiloxane

[0060] Weigh out 35g of dodecafluoroheptylpropylmethyldimethoxysilane, 80g of octamethylcyclotetrasiloxane, and 20mL of 80wt% sulfuric acid and add them to a reaction flask. Stir the mixture and raise the temperature of the reaction flask to 90℃. Keep the reaction temperature at 160min. Add 14g of (1,1,3,3-tetramethyl-1,3-disiloxanediyl)diethanol to the reaction flask and keep the reaction temperature at 90min. Lower the temperature of the reaction flask to room temperature and add 2wt% sodium carbonate aqueous solution to adjust the pH of the system to 7. Allow the mixture to stand and separate the layers. Wash the upper organic matter three times with purified water and transfer it to a rotary evaporator with a water bath temperature of 85℃. Apply a negative pressure to -0.1MPa and remove low-boiling substances by vacuum evaporation to obtain fluorinated polysiloxane.

[0061] Step 2: Preparation of composite polyurethane

[0062] Weigh out 100g of polytetrahydrofuran ether glycol, 45g of fluorinated polysiloxane, and 300mL of toluene and add them to an argon-protected reaction flask. Stir until the system dissolves. Raise the temperature of the reaction flask to 65℃. Add 1g of dibutyltin dilaurate catalyst to the reaction flask and stir for 5min. Calculate the amount of diphenylmethane 4,4ˊ-diisocyanate to be added to the reaction flask based on 0.57 times the total molar amount of hydroxyl groups in the mixed system of polytetrahydrofuran ether glycol and fluorinated polysiloxane. Keep the reaction temperature high for 70min. Add 30g of glycidyl ether to the reaction flask and keep the reaction temperature high for 70min. Raise the temperature of the reaction flask to 85℃ and apply a negative pressure to -0.1MPa. Remove low-boiling-point substances by vacuum evaporation to obtain composite polyurethane.

[0063] Step 3: Preparation of shielding particles

[0064] Ferric chloride, ferrous chloride, deionized water, ethylene glycol and sodium dodecyl sulfate were mixed and stirred until the system was dissolved to obtain an iron-based dispersion.

[0065] Weigh out 25g of graphene oxide, 35g of nano-alumina and 1L of iron-based dispersion and add them to a reaction flask. Mix and ultrasonically disperse for 60min. Fix the reaction flask on an iron stand with mechanical stirring and stir. Add 6mol / L ammonia water to the reaction flask to adjust the pH of the system to 10.5. Raise the temperature of the reaction flask to 65℃ and keep it at this temperature for 2.5h. Lower the temperature of the reaction flask to room temperature and filter. Wash the filter cake with purified water until neutral and then dry it. Transfer the filter cake to a drying oven at 65℃ and vacuum dry it to constant weight to obtain metal-doped graphene.

[0066] Weigh out 50g of metal-doped graphene and 2L of buffer solution and add them to the reaction flask. Mix and sonicate for 40min. Fix the reaction flask on an iron stand with mechanical stirring and stir. Add 14g of dopamine hydrochloride to the reaction flask and react at room temperature for 7h. Filter and wash the filter cake with purified water until neutral. Dry the filter cake and transfer it to a drying oven at 80℃. Dry until constant weight to obtain shielding particles. The buffer solution is aminomethane buffer with a concentration of 0.1mol / L and pH=8.5.

[0067] Step 4: Prepare the network cable

[0068] Several groups of wire cores are arranged in parallel and twisted together to form a wire core bundle;

[0069] Dioctyl phthalate, antioxidant 1076, calcium stearate, and ethylene dioleamide were mixed in a weight ratio of 4:1:2:1 to obtain an auxiliary additive.

[0070] Weigh out the following components by weight: 75 parts of composite polyurethane, 30 parts of bisphenol A epoxy resin, 23 parts of shielding particles, and 4 parts of auxiliary additives. Mix them evenly and add them to a twin-screw extruder. Set the temperatures of the five temperature zones of the twin-screw extruder from the feed end to the discharge end to 155℃, 160℃, 160℃, 160℃, and 165℃ respectively. Melt and mix for 2.5 minutes, then extrude and coat the outside of the core bundle. Cool and cure to form an outer sheath with a thickness of 0.75mm, thus obtaining a sample of the network cable product.

[0071] Example 3

[0072] This embodiment provides a method for preparing a wear-resistant wire with high shielding effectiveness, including the following steps:

[0073] Step 1: Preparation of fluorine-modified polysiloxane

[0074] Weigh out 40g of dodecafluoroheptylpropylmethyldimethoxysilane, 80g of octamethylcyclotetrasiloxane, and 20mL of 85wt% sulfuric acid and add them to a reaction flask. Stir the mixture and raise the temperature of the reaction flask to 95℃. Maintain the temperature for 180min. Add 15g of (1,1,3,3-tetramethyl-1,3-disiloxanediyl)diethanol to the reaction flask and maintain the temperature for 100min. Lower the temperature of the reaction flask to room temperature and add 2wt% sodium carbonate aqueous solution to adjust the pH of the system to 7. Allow the mixture to stand and separate the layers. Wash the upper organic matter three times with purified water and transfer it to a rotary evaporator with a water bath temperature of 90℃. Apply a negative pressure to -0.1MPa and remove low-boiling substances by vacuum evaporation to obtain fluorinated polysiloxane.

[0075] Step 2: Preparation of composite polyurethane

[0076] Weigh out 100g of polytetrahydrofuran ether glycol, 50g of fluorinated polysiloxane, and 300mL of toluene and add them to an argon-protected reaction flask. Stir until the system dissolves. Raise the temperature of the reaction flask to 70℃. Add 1g of dibutyltin dilaurate catalyst to the reaction flask and stir for 5min. Calculate the amount of diphenylmethane 4,4ˊ-diisocyanate to be added to the reaction flask based on 0.58 times the total molar amount of hydroxyl groups in the mixed system of polytetrahydrofuran ether glycol and fluorinated polysiloxane. Keep the reaction temperature high for 80min. Add 30g of glycidyl ether to the reaction flask and keep the reaction temperature high for 80min. Raise the temperature of the reaction flask to 90℃ and apply a negative pressure to -0.1MPa. Remove low-boiling-point substances by vacuum evaporation to obtain composite polyurethane.

[0077] Step 3: Preparation of shielding particles

[0078] Ferric chloride, ferrous chloride, deionized water, ethylene glycol and sodium dodecyl sulfate were mixed and stirred until the system was dissolved to obtain an iron-based dispersion.

[0079] Weigh out 30g of graphene oxide, 40g of nano-alumina and 1L of iron-based dispersion and add them to a reaction flask. Mix and ultrasonically disperse for 70min. Fix the reaction flask on an iron stand with mechanical stirring and stir. Add 6mol / L ammonia to the reaction flask to adjust the pH of the system to 11. Raise the temperature of the reaction flask to 70℃ and keep it at this temperature for 3h. Lower the temperature of the reaction flask to room temperature and filter. Wash the filter cake with purified water until neutral and then dry it. Transfer the filter cake to a drying oven at 70℃ and vacuum dry it to constant weight to obtain metal-doped graphene.

[0080] Weigh out 50g of metal-doped graphene and 2L of buffer solution and add them to the reaction flask. Mix and sonicate for 50min. Fix the reaction flask on an iron stand with mechanical stirrer and stir. Add 15g of dopamine hydrochloride to the reaction flask and react at room temperature for 8h. Filter and wash the filter cake with purified water until neutral. Dry the filter cake and transfer it to a drying oven at 85℃. Dry until constant weight to obtain shielding particles. The buffer solution is aminomethane buffer with a concentration of 0.1mol / L and pH=8.5.

[0081] Step 4: Prepare the network cable

[0082] Several groups of wire cores are arranged in parallel and twisted together to form a wire core bundle;

[0083] Diisooctyl phthalate, antioxidant 1010, sodium stearate, and ethylene dioleamide were mixed in a weight ratio of 4:1:2:1 to obtain an auxiliary additive.

[0084] Weigh out the following components by weight: 80 parts of composite polyurethane, 35 parts of bisphenol A epoxy resin, 26 parts of shielding particles, and 5 parts of auxiliary additives. Mix them evenly and add them to a twin-screw extruder. Set the temperatures of the five temperature zones of the twin-screw extruder from the feed end to the discharge end to 155℃, 160℃, 160℃, 160℃, and 165℃ respectively. Melt and mix for 3 minutes, then extrude and coat the outside of the core bundle. Cool and cure to form an outer sheath with a thickness of 0.8mm, thus obtaining a sample of the network cable product.

[0085] Comparative Example 1

[0086] The difference between this comparative example and Example 3 is that, in step one, dodecafluoroheptylpropylmethyldimethoxysilane was not added.

[0087] Comparative Example 2

[0088] The difference between this comparative example and Example 3 is that, in step three, a mixture of graphene oxide and nano-alumina in a weight ratio of 5:7 is used to replace metal-doped graphene in the preparation of shielding particles.

[0089] Comparative Example 3

[0090] The difference between this comparative example and Example 3 is that the metal-doped graphene in step 3 replaces the shielding particles in step 4.

[0091] Comparative Example 4

[0092] The difference between this comparative example and Example 3 is that bisphenol A type epoxy resin was not added in step four.

[0093] Performance testing:

[0094] The electromagnetic shielding effectiveness of the outer sheath of the network cable product samples prepared in Examples 1-3 and Comparative Examples 1-4 was determined in accordance with the standard "General Technical Requirements for Electromagnetic Shielding Plastics".

[0095] The abrasion resistance of the outer sheath of the network cable product samples prepared in Examples 1-3 and Comparative Examples 1-4 was determined according to the standard GB / T 17737.324-2018 "Coaxial Communication Cables - Part 1-324: Mechanical Test Methods - Cable Abrasion Resistance Test". The applied force was 45N, and the test endpoint was the number of complete cycles when the cable was worn through by a blade.

[0096] The tensile strength and elongation at break of the outer sheath of the wire mesh product samples prepared in Examples 1-3 and Comparative Examples 1-4 were determined in accordance with the standard GB / T 1040.3-2006 "Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets". The tensile test rate was 20 mm / min. The specific test data are shown in Table 1 below.

[0097] Table 1 - Performance Test Data of Samples

[0098] Group Project Tensile strength / MPa Elongation at break / % Number of wear-resistant cycles / times Electromagnetic shielding effectiveness / dB Example 1 35.6 235 3000 62 Example 2 35.8 240 3050 65 Example 3 35.7 238 3030 63 Comparative Example 1 35.1 185 2000 59 Comparative Example 2 35.4 229 2350 48 Comparative Example 3 31.5 157 1780 56 Comparative Example 4 26.7 253 2170 61

[0099] Data Analysis:

[0100] Comparative analysis of the data in Table 1 shows that the tensile strength of the outer sheath of the network cable product prepared by this invention reaches 35.8 MPa, the elongation at break reaches 240%, the number of abrasion cycles reaches 3050, and the electromagnetic shielding effectiveness reaches 65 dB. All performance test data are superior to the comparative example. This indicates that this invention, by copolymerizing fluorine-modified polysiloxane with polytetrahydrofuran ether diol to form a composite polyurethane, and introducing bisphenol A type epoxy resin and polydopamine-coated metal-doped graphene shielding particles to synergistically construct a flexible, dense outer sheath structure that also provides electromagnetic shielding, enables the network cable to simultaneously possess excellent mechanical strength, abrasion resistance, and electromagnetic shielding effectiveness.

[0101] 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 wear-resistant network cable with high shielding effectiveness, comprising several sets of wire cores and an outer sheath, characterized in that, The outer sheath comprises the following components by weight: 70-80 parts of composite polyurethane, 25-35 parts of bisphenol A epoxy resin, 20-26 parts of shielding particles, and 3-5 parts of auxiliary additives. The shielding particles are metal-doped graphene coated with polydopamine. The preparation method of the composite polyurethane is as follows: under an inert gas atmosphere, polytetrahydrofuran ether diol, fluorinated polysiloxane and toluene are mixed and stirred until the system is dissolved. The temperature of the reaction system is raised to 60-70℃. A catalyst and diphenylmethane 4,4ˊ-diisocyanate are added to the reaction system. The reaction is kept at this temperature for 60-80 min. Glycidyl ether is added to the reaction system. The reaction is kept at this temperature for 60-80 min. After post-treatment, the composite polyurethane is obtained. The preparation method of the fluorinated polysiloxane is as follows: dodecafluoroheptylpropylmethyldimethoxysilane, octamethylcyclotetrasiloxane and sulfuric acid are mixed and stirred, the temperature of the reaction system is raised to 85-95℃, and the reaction is maintained at this temperature for 140-180 min. Then (1,1,3,3-tetramethyl-1,3-disiloxanediyl)diethanol is added to the reaction system, and the reaction is maintained at this temperature for 80-100 min. After post-treatment, the fluorinated polysiloxane is obtained. The shielding particles are prepared by mixing metal-doped graphene and buffer solution, ultrasonically dispersing for 30-50 min, adding dopamine hydrochloride to the reaction system, reacting at room temperature for 6-8 h, and then post-processing to obtain the shielding particles. The preparation method of metal-doped graphene is as follows: graphene oxide, nano-alumina and iron-based dispersion are mixed and ultrasonically dispersed for 50-70 min. Ammonia water is added to the reaction system to adjust the pH of the system to 10-11. The temperature of the reaction system is raised to 60-70℃ and stirred for 2-3 h. After post-treatment, metal-doped graphene is obtained.

2. The wear-resistant network cable with high shielding effectiveness according to claim 1, characterized in that, The ratio of polytetrahydrofuran ether diol, fluorinated polysiloxane, toluene, catalyst, and glycidyl is 10g:4-5g:30mL:0.1g:3g. The catalyst is dibutyltin dilaurate. The molar amount of diphenylmethane 4,4'-diisocyanate is 0.55-0.58 times the total molar amount of hydroxyl groups in polytetrahydrofuran ether diol and fluorinated polysiloxane.

3. The wear-resistant network cable with high shielding effectiveness according to claim 1, characterized in that, The weight ratio of dodecafluoroheptylpropylmethyldimethoxysilane, octamethylcyclotetrasiloxane, sulfuric acid, and (1,1,3,3-tetramethyl-1,3-disiloxanediyl)diethanol is 3-4 g: 8 g: 2 mL: 1.3-1.5 g, and the concentration of sulfuric acid is 75-85%.

4. The wear-resistant network cable with high shielding effectiveness according to claim 1, characterized in that, The ratio of the metal-doped graphene, buffer solution, and dopamine hydrochloride is 5g:200mL:1.3-1.5g.

5. The wear-resistant network cable with high shielding effectiveness according to claim 1, characterized in that, The ratio of the amount of graphene oxide, nano-alumina and iron-based dispersion is 2-3g:3-4g:100mL. The iron-based dispersion is composed of ferric chloride, ferrous chloride, deionized water, ethylene glycol and sodium dodecyl sulfate in the ratio of 2g:1g:70-80mL:10-20mL:0.8-1.2g.

6. A method for preparing a wear-resistant mesh cable with high shielding effectiveness according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Arrange several groups of wire cores in parallel and twist them together to form a wire core bundle; S2. After uniformly mixing the composite polyurethane, bisphenol A type epoxy resin, shielding particles and auxiliary additives, add them to a twin-screw extruder, melt mix for 2-3 minutes, extrude and coat the outside of the core bundle, cool and cure to form an outer sheath with a thickness of 0.7-0.8 mm.

7. The method for preparing a wear-resistant mesh cable with high shielding effectiveness according to claim 6, characterized in that, The auxiliary additives are composed of plasticizer, antioxidant, dispersant and lubricant in a weight ratio of 4:1:2:

1. The plasticizer is phthalate, the antioxidant is either antioxidant 1010 or antioxidant 1076, the dispersant is stearate, and the lubricant is ethylene bisoleamide. The temperatures of the five temperature zones of the twin-screw extruder from the feed end to the discharge end are 155℃, 160℃, 160℃, 160℃ and 165℃ respectively.

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