Anti-aging and anti-cracking three-layer insulated wire and preparation method thereof

Abstract

The invention discloses an anti-aging and anti-cracking three-layer insulated wire and a preparation method thereof, and belongs to the technical field of cable conductors, the anti-aging and anti-cracking three-layer insulated wire is composed of a copper wire, an inner insulating layer, a middle insulating layer and an outer protective layer from inside to outside, the inner insulating layer and the middle insulating layer are prepared from insulating layer rubber materials, and the insulating layer rubber materials comprise, by mass, 1-10 parts of an anti-aging and anti-cracking agent and 1-10 parts of an anti-aging and anti-cracking agent. The composite material comprises the following components in parts by weight: 10-15 parts of polybutylene terephthalate, 40-50 parts of polyethylene glycol terephthalate, 20-30 parts of reinforced epoxy resin powder, 3-5 parts of color master batch and 10-15 parts of thermoplastic polyester elastomer, the graphene nanosheets containing zinc oxide are compounded on the surfaces of the glass fibers, the ultraviolet resistance of the three-layer insulated wire is improved, the modified graphene oxide compound glass fibers are combined with the epoxy resin through the reaction of sulfydryl and epoxy groups, the dispersity of the modified graphene oxide compound glass fibers is improved, and the ultraviolet resistance of the three-layer insulated wire is improved. And the mechanical strength and the ultraviolet resistance of the three-layer insulated wire are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of cable wires, and particularly relates to a three-layer insulated wire resistant to aging and cracking and a preparation method thereof. Background Art

[0002] The three-layer insulated wire is a high-performance insulated wire. This wire has three insulating layers. The middle is a copper core wire. The first layer is a golden polyamine film with a thickness of only a few micrometers, but it can withstand a pulsed high voltage of 2 kV. The second layer is a high-insulation paint coating. The third layer is a transparent nylon-modified glass fiber layer. The insulating layer material can be a soft-soldering polyester-based heat-resistant resin and a polyamide-based resin. The total thickness of the insulating layer is only 20 - 100 μm. Its advantages are high insulation strength. Any two layers can withstand a safe voltage of 2000 V AC, and the current density is large, which can reduce the weight and volume of the transformer. However, during the production and use of a single PET resin mixture, problems such as aging and cracking after use under high-temperature conditions (230 °C / 30 minutes), reduction of product performance, and occurrence of defective products exist.

[0003] The Chinese patent application with the publication number CN108976672A discloses a cable insulation material resistant to aging and its preparation method. By performing a hydrothermal reaction on kaolin, aluminum salt, tin salt, alkali, and water and chelating on the kaolin, the interface reflection performance of the kaolin is improved, and the ability of the material to shield ultraviolet rays is improved, obtaining a cable insulation material with good ultraviolet resistance and aging resistance; however, in the three-layer insulated wire, both glass fiber and kaolin need to add silane coupling agents and dispersants to promote the dispersibility of glass fiber and kaolin in the polyester-based heat-resistant resin. The large addition of silane coupling agents and dispersants will cause a decrease in the tensile strength of the insulation material and is more likely to age and crack.

[0004] The Chinese patent application with the publication number CN109754923A discloses an insulated wire and its preparation method. By mixing polyethylene terephthalate with different component raw materials to respectively prepare three-layer insulation layer materials and successively coating them on a metal wire, a three-layer insulated wire with high temperature resistance and aging resistance is obtained; however, in this scheme, no reinforcing fillers such as glass fiber are added, and the obtained insulated wire has low strength and cannot meet the high-performance standards of the three-layer insulated wire. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem of how to compound ultraviolet-resistant fillers and reinforcing fillers to improve the aging resistance, and to provide a three-layer insulated wire resistant to aging and cracking and a preparation method thereof.

[0006] By compounding graphene oxide nanosheets containing zinc oxide on the surface of glass fiber, the present invention improves the ultraviolet resistance of the triple-insulated wire. Utilizing the reaction between mercapto groups and epoxy groups, the modified graphene oxide composite glass fiber is combined with epoxy resin, improving the dispersibility of the modified graphene oxide composite glass fiber and enhancing the mechanical strength and ultraviolet resistance of the triple-insulated wire.

[0007] The object of the present invention can be achieved by the following technical solutions:

[0008] A triple-insulated wire resistant to aging and cracking is composed of a copper wire, an inner insulating layer, an intermediate insulating layer, and an outer protective layer from the inside out. The inner insulating layer and the intermediate insulating layer are made of insulating layer rubber compound. The insulating layer rubber compound, by mass, comprises the following components:

[0009] 10 - 15 parts of polybutylene terephthalate, 40 - 50 parts of polyethylene terephthalate, 20 - 30 parts of reinforced epoxy resin powder, 3 - 5 parts of color masterbatch, and 10 - 15 parts of thermoplastic polyester elastomer.

[0010] Further, the reinforced epoxy resin powder is prepared by the following steps:

[0011] Step 1: In a reaction kettle, zinc oxide / graphene oxide nanosheets and MOF composite glass fiber are compounded under the action of 3-mercaptopropyltrimethoxysilane to obtain modified graphene oxide composite glass fiber.

[0012] Step 2: In a reaction kettle, bisphenol A epoxy resin and isopropanol are heated and stirred to dissolve. Modified graphene oxide composite glass fiber and tetramethylammonium chloride are added, and the temperature is raised to 60 - 80°C and stirred for 4 - 6 h. After rotary evaporation to remove the solvent, it is dried, pulverized, and sieved through a 200-mesh sieve to obtain the reinforced epoxy resin powder.

[0013] Further, the dosage ratio of bisphenol A epoxy resin, isopropanol, modified graphene oxide composite glass fiber, and tetramethylammonium chloride in Step 2 is 20 - 30 g : 10 - 15 mL : 2 - 3 g : 0.2 - 0.3 g.

[0014] Further, the modified graphene oxide composite glass fiber in Step 1 is specifically prepared by the following steps:

[0015] In a reaction kettle, MOF composite glass fiber and a dispersion liquid are mixed. 3-mercaptopropyltrimethoxysilane is added, and it is oscillated for 20 - 24 h. The precipitate is filtered, washed, and dried to obtain the modified graphene oxide composite glass fiber.

[0016] Further, the dosage ratio of the MOF composite glass fiber, the dispersion liquid, and 3-mercaptopropyltrimethoxysilane is 2 - 3 g : 2 - 3 L : 1 - 2 g; the concentration of the dispersion liquid is 100 mg / L, which is prepared by ultrasonically dispersing zinc oxide / graphene nanosheets in a 50 wt% ethanol aqueous solution.

[0017] Further, the MOF composite glass fiber is prepared by the following steps:

[0018] Dissolve ferric chloride hexahydrate in deionized water in a reaction kettle, add acetic acid, stir for 2 - 3 h, then add 2-aminoterephthalic acid and stir for another 2 - 3 h. Then add carboxylated glass fiber into the reaction kettle, heat up to 120 - 130 °C and react for 20 - 24 h. Filter to obtain a precipitate, wash the precipitate, and obtain the MOF composite glass fiber after vacuum drying.

[0019] Further, the dosage ratio of ferric chloride hexahydrate, deionized water, acetic acid, 2-aminoterephthalic acid, and carboxylated glass fiber is 2 - 2.5 g : 150 - 180 mL : 5 - 6 mL : 0.8 - 1.2 g : 1 - 1.5 g.

[0020] Further, the carboxylated glass fiber is prepared by the following steps:

[0021] Ultrasonically disperse glass fiber in DMF in a reaction kettle, add the silane coupling agent APTES and a 4 - 5 wt% succinic anhydride DMF solution into the reaction kettle, stir for 20 - 24 h, centrifuge to collect the precipitate, wash the precipitate, and obtain the carboxylated glass fiber after drying.

[0022] Further, the dosage ratio of glass fiber, DMF, silane coupling agent APTES, and succinic anhydride DMF solution is 10 - 15 g : 500 - 600 mL : 3 - 4 g : 100 - 150 mL.

[0023] Further, the zinc oxide / graphene nanosheets are prepared by the following steps:

[0024] Thermally reduce graphene oxide nanosheets to obtain reduced graphene oxide. Ultrasonically disperse the reduced graphene oxide in deionized water in a reaction kettle, add 1 M zinc acetate solution and 1 M ammonia water, ultrasonically disperse for 30 - 40 min, then heat up to 170 - 180 °C and react for 20 - 24 h. Centrifuge to collect the precipitate, wash the precipitate, and obtain the zinc oxide / graphene nanosheets after vacuum drying.

[0025] Further, the dosage ratio of reduced graphene oxide, deionized water, zinc acetate solution, and ammonia water is 5 - 8 g : 500 - 800 mL : 20 - 30 mL : 30 - 40 mL.

[0026] A preparation method of an anti-aging and anti-cracking three-layer insulated wire comprises the following steps:

[0027] Mix polybutylene terephthalate, polyethylene terephthalate, reinforced epoxy resin powder, masterbatch and thermoplastic polyester elastomer, and bake them in an oven at 120 - 130 °C for 5 - 6 h. Then transfer them to a feeding hopper for discharging. After the discharged compound is delicate and free of granularity, the insulating layer compound is obtained. Use a three-layer insulated wire tandem extrusion production line to co-extrude an insulating layer and a protective layer with a copper wire. The copper wire is the core, nylon is the protective layer, and the insulating layer compound is the inner insulating layer and the middle insulating layer to obtain a three-layer insulated wire with anti-aging and cracking resistance.

[0028] Advantages of the present invention:

[0029] 1. The three-layer insulated wire with anti-aging and cracking resistance prepared by the present invention uses glass fiber as the matrix, and graphene oxide nanosheets containing zinc oxide are compounded on the surface of the glass fiber, which improves the ultraviolet resistance of the three-layer insulated wire. The bonding strength and dispersibility of MOF composite glass fiber and zinc oxide / graphene oxide nanosheets are enhanced by silane coupling agent, and mercapto groups are grafted on the surface. By using the reaction between mercapto groups and epoxy groups, the modified graphene oxide composite glass fiber is combined with epoxy resin, and the dispersibility of the modified graphene oxide composite glass fiber in polybutylene terephthalate and polyethylene terephthalate is improved, resulting in a three-layer insulated wire with good mechanical strength and strong ultraviolet aging resistance.

[0030] 2. In the present invention, zinc oxide particles are in-situ generated on the surface of graphene oxide nanosheets. Zinc oxide has anti-ultraviolet performance, and it can cooperate with graphene oxide nanosheets to enhance the anti-ultraviolet ability of zinc oxide / graphene oxide nanosheets. By using the reaction between carboxyl groups and 2-aminoterephthalic acid on the surface of carboxylated glass fiber powder, 2-aminoterephthalic acid is grafted on the surface of carboxylated glass fiber, so that Fe-MOF with 2-aminoterephthalic acid as the ligand is in-situ synthesized on the surface of carboxylated glass fiber, and the surface of carboxylated glass fiber contains amino groups, thereby enhancing the hydrogen bond binding ability between carboxylated glass fiber and zinc oxide / graphene oxide nanosheets, and improving the binding uniformity and binding strength of MOF composite glass fiber and zinc oxide / graphene oxide nanosheets. Specific embodiments

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

[0032] Example 1: A preparation method of a three-layer insulated wire with anti-aging and cracking resistance, comprising the following steps:

[0033] S1. Thermally reduce graphene oxide nanosheets to obtain reduced graphene oxide. Ultrasonically disperse 5 g of reduced graphene oxide in 500 mL of deionized water in a reaction kettle. Add 20 mL of 1 M zinc acetate solution and 30 mL of 1 M ammonia water. After ultrasonic treatment for 30 min, raise the temperature to 170 °C and react for 20 h. After cooling, centrifuge to collect the precipitate, wash the precipitate with ethanol and deionized water, and dry it in vacuum at 70 °C for 20 h to obtain zinc oxide / graphene nanosheets.

[0034] S2. Ultrasonically disperse 10 g of glass fiber in 500 mL of DMF in a reaction kettle. Add 3 g of silane coupling agent APTES and 100 mL of 4 wt% succinic anhydride DMF solution to the reaction kettle, stir for 20 h, centrifuge to collect the precipitate, wash the precipitate with ethanol and deionized water, and dry it at 60 °C for 10 h to obtain carboxylated glass fiber.

[0035] S3. Dissolve 2 g of ferric chloride hexahydrate in 150 mL of deionized water in a reaction kettle. Add 5 mL of acetic acid and stir for 2 h. Then add 0.8 g of 2-aminoterephthalic acid and stir for another 2 h. Then add 1 g of carboxylated glass fiber to the reaction kettle, raise the temperature to 120 °C and react for 20 h. After cooling, filter to obtain the precipitate, wash the precipitate with ethanol and deionized water, and dry it in vacuum at 60 °C for 20 h to obtain MOF composite glass fiber.

[0036] S4. Ultrasonically disperse zinc oxide / graphene nanosheets in a 50 wt% ethanol aqueous solution in a reaction kettle to prepare a dispersion with a concentration of 100 mg / mL. Mix 2 g of MOF composite glass fiber with 2 L of the dispersion in the reaction kettle. Add 1 g of 3-mercaptopropyltrimethoxysilane, and oscillate at 100 rpm at room temperature for 20 h. Filter to obtain the precipitate, wash the precipitate with deionized water, and dry it at 70 °C for 10 h to obtain modified graphene oxide composite glass fiber.

[0037] S5. Heat and stir to dissolve 20 g of bisphenol A epoxy resin and 10 mL of isopropanol in a reaction kettle. Add 2 g of modified graphene oxide composite glass fiber and 0.2 g of tetramethylammonium chloride. Raise the temperature to 60 °C and stir and react for 4 h. Then rotary evaporate to remove the solvent, dry and crush it through a 200-mesh sieve to obtain reinforced epoxy resin powder.

[0038] S6. Mix 10 g of polybutylene terephthalate, 40 g of polyethylene terephthalate, 20 g of reinforced epoxy resin powder, 3 g of color masterbatch, and 10 g of thermoplastic polyester elastomer, then bake them in an oven at 120 °C for 5 h. Transfer them to a feed hopper for discharging. After the discharged compound is delicate and free of granularity, the insulating layer compound is obtained. Nylon is used as the protective layer. Use a three-layer insulated wire tandem extrusion production line to process and co-extrude the insulating layer and the protective layer with a copper wire. The extrusion temperature of the inner insulating layer is 255 °C, the extrusion temperature of the middle insulating layer is 255 °C, the extrusion temperature of the outer protective layer is 260 °C. The copper wire is the core. The thickness of the inner insulating layer is 0.06 mm, the thickness of the middle insulating layer is 0.05 mm, and the thickness of the outer protective layer is 0.06 mm, obtaining a three-layer insulated wire resistant to aging and cracking.

[0039] Example 2: A preparation method of a three-layer insulated wire resistant to aging and cracking, comprising the following steps:

[0040] S1. Thermally reduce graphene oxide nanosheets to obtain reduced graphene oxide. Ultrasonically disperse 6.5 g of reduced graphene oxide in 650 mL of deionized water in a reaction kettle, add 25 mL of 1 M zinc acetate solution and 35 mL of 1 M ammonia water, ultrasonically treat for 35 min, then heat up to 175 °C and react for 22 h. After cooling, centrifuge to collect the precipitate, wash the precipitate with ethanol and deionized water, and vacuum dry at 75 °C for 22 h to obtain zinc oxide / graphene nanosheets.

[0041] S2. Ultrasonically disperse 12.5 g of glass fiber in 550 mL of DMF in a reaction kettle. Add 3.5 g of silane coupling agent APTES and 125 mL of 4.5 wt% succinic anhydride DMF solution to the reaction kettle, stir for 22 h, centrifuge to collect the precipitate, wash the precipitate with ethanol and deionized water, and dry at 65 °C for 11 h to obtain carboxylated glass fiber.

[0042] S3. Dissolve 2.25 g of ferric chloride hexahydrate in 165 mL of deionized water in a reaction kettle, add 5.5 mL of acetic acid, stir for 2.5 h, then add 1.0 g of 2-aminoterephthalic acid and stir for another 2.5 h. Then add 1.25 g of carboxylated glass fiber to the reaction kettle, heat up to 125 °C and react for 22 h. After cooling, filter to obtain the precipitate, wash the precipitate with ethanol and deionized water, and vacuum dry at 65 °C for 22 h to obtain MOF composite glass fiber.

[0043] S4. In a reaction kettle, zinc oxide / graphene nanosheets were ultrasonically dispersed in an aqueous ethanol solution of 50 wt% to prepare a dispersion with a concentration of 100 mg / mL. 2.5 g of MOF composite glass fiber was mixed with 2.5 L of the dispersion in the reaction kettle, 1.5 g of 3-mercaptopropyltrimethoxysilane was added, and the mixture was oscillated at 125 rpm at room temperature for 22 h. The precipitate was obtained by filtration, washed with deionized water, and dried at 75 °C for 11 h to obtain modified graphene oxide composite glass fiber.

[0044] S5. In a reaction kettle, 25 g of bisphenol A epoxy resin and 12.5 mL of isopropanol were heated and stirred to dissolve. 2.5 g of modified graphene oxide composite glass fiber and 0.25 g of tetramethylammonium chloride were added, and the temperature was raised to 70 °C and stirred for 5 h. Then the solvent was removed by rotary evaporation, dried and crushed through a 200-mesh sieve to obtain reinforced epoxy resin powder.

[0045] S6. 12.5 g of polybutylene terephthalate, 45 g of polyethylene terephthalate, 25 g of reinforced epoxy resin powder, 4 g of color masterbatch, and 12.5 g of thermoplastic polyester elastomer were mixed and baked in an oven at 125 °C for 5.5 h, then transferred to a hopper for discharging. After the discharged rubber compound was delicate and free of particles, the insulating layer rubber compound was obtained. Nylon was used as the protective layer, and a three-layer insulated wire string extrusion production line was used to co-extrude the insulating layer and the protective layer with a copper wire. The extrusion temperature of the inner insulating layer was 282.5 °C, the extrusion temperature of the middle insulating layer was 280 °C, and the extrusion temperature of the outer protective layer was 285 °C. The copper wire was used as the core. The thickness of the inner insulating layer was 0.07 mm, the thickness of the middle insulating layer was 0.06 mm, and the thickness of the outer protective layer was 0.07 mm, obtaining a three-layer insulated wire with anti-aging and anti-cracking properties.

[0046] Example 3: A preparation method of a three-layer insulated wire with anti-aging and anti-cracking properties, comprising the following steps:

[0047] S1. Thermally reduce graphene oxide nanosheets to obtain reduced graphene oxide. In a reaction kettle, 8 g of reduced graphene oxide was ultrasonically dispersed in 800 mL of deionized water, 30 mL of 1 M zinc acetate solution and 40 mL of 1 M ammonia water were added, ultrasonically treated for 40 min, then heated to 180 °C and reacted for 24 h. After cooling, the precipitate was collected by centrifugation, washed with ethanol and deionized water, and vacuum dried at 80 °C for 24 h to obtain zinc oxide / graphene nanosheets.

[0048] S2. In a reaction kettle, 15 g of glass fiber was ultrasonically dispersed in 600 mL of DMF. 4 g of silane coupling agent APTES and 150 mL of 5 wt% succinic anhydride DMF solution were added to the reaction kettle, stirred for 24 h, the precipitate was collected by centrifugation, washed with ethanol and deionized water, and dried at 70 °C for 12 h to obtain carboxylated glass fiber.

[0049] S3. Dissolve 2.5 g of ferric chloride hexahydrate in 180 mL of deionized water in a reaction kettle, add 6 mL of acetic acid, stir for 3 h, then add 1.2 g of 2-aminoterephthalic acid and stir for another 3 h. Then add 1.5 g of carboxylated glass fiber into the reaction kettle, heat up to 130 °C and react for 24 h. After cooling, filter to obtain a precipitate, wash the precipitate with ethanol and deionized water, and dry it under vacuum at 70 °C for 24 h to obtain MOF composite glass fiber.

[0050] S4. Ultrasonically disperse zinc oxide / graphene nanosheets in a 50 wt% ethanol aqueous solution in a reaction kettle to prepare a dispersion with a concentration of 100 mg / mL. Mix 3 g of MOF composite glass fiber with 3 L of the dispersion in the reaction kettle, add 2 g of 3-mercaptopropyltrimethoxysilane, oscillate at 150 rpm at room temperature for 24 h, filter to obtain a precipitate, wash the precipitate with deionized water, and dry it at 80 °C for 12 h to obtain modified graphene oxide composite glass fiber.

[0051] S5. Heat and stir to dissolve 30 g of bisphenol A epoxy resin and 15 mL of isopropanol in a reaction kettle, add 3 g of modified graphene oxide composite glass fiber and 0.3 g of tetramethylammonium chloride, heat up to 80 °C and stir to react for 6 h. Then rotary evaporate to remove the solvent, dry and crush it through a 200-mesh sieve to obtain reinforced epoxy resin powder.

[0052] S6. Mix 15 g of polybutylene terephthalate, 50 g of polyethylene terephthalate, 30 g of reinforced epoxy resin powder, 5 g of color masterbatch and 15 g of thermoplastic polyester elastomer, bake them in an oven at 130 °C for 6 h, transfer them to a feeding hopper for discharging. After the discharged rubber material is delicate and free of particles, obtain the insulating layer rubber material. Use nylon as the protective layer, and use a three-layer insulated wire tandem extrusion production line to process and co-extrude the insulating layer and the protective layer with a copper wire. The extrusion temperature of the inner insulating layer is 310 °C, the extrusion temperature of the middle insulating layer is 305 °C, the extrusion temperature of the outer protective layer is 310 °C. The copper wire is the core, the thickness of the inner insulating layer is 0.08 mm, the thickness of the middle insulating layer is 0.07 mm, and the thickness of the outer protective layer is 0.08 mm to obtain a three-layer insulated wire resistant to aging and cracking.

[0053] Principle of the invention:

[0054] In the present invention, zinc oxide particles are in-situ generated on the surface of graphene nanosheets. Zinc oxide has ultraviolet resistance, and when it acts synergistically with graphene nanosheets, the ultraviolet resistance of zinc oxide / graphene nanosheets can be enhanced. By using the reaction of carboxyl groups with 2-aminoterephthalic acid on the surface of carboxylated glass fiber powder, 2-aminoterephthalic acid is grafted onto the surface of carboxylated glass fiber, enabling the in-situ synthesis of Fe-MOF with 2-aminoterephthalic acid as a ligand on the surface of carboxylated glass fiber, so that the surface of carboxylated glass fiber contains amino groups, thereby enhancing the hydrogen bond binding ability between carboxylated glass fiber and zinc oxide / graphene nanosheets and improving the binding uniformity and binding strength of MOF composite glass fiber and zinc oxide / graphene nanosheets.

[0055] In the present invention, 3-mercaptopropyltrimethoxysilane is used as a silane coupling agent to promote the binding of MOF composite glass fiber and zinc oxide / graphene nanosheets. At the same time, mercapto groups are grafted onto the surface of modified graphene oxide composite glass fiber. The epoxy groups in epoxy resin react and graft with mercapto groups under the action of ring-opening agent tetramethylammonium chloride and amino groups in the MOF ligand, dispersing and binding the modified graphene oxide composite glass fiber evenly in the reinforced epoxy resin powder. By utilizing the compatibility between epoxy resin and polybutylene terephthalate and polyethylene terephthalate, the reinforcing and modifying effect of modified graphene oxide composite glass fiber on the insulating layer rubber compound is enhanced. The insulating layer rubber compound with glass fiber as the modified matrix has high mechanical strength, and the surface of the glass fiber is compounded with ultraviolet-resistant fillers, enhancing the dispersibility of the ultraviolet-resistant fillers and glass fiber, thereby improving the anti-aging and cracking performance of the three-layer insulating wire.

[0056] Comparative Example 1: The difference from Example 1 is that in S4, carboxylated glass fiber is used to replace an equal mass of MOF composite glass fiber, and the remaining steps remain unchanged, obtaining a three-layer insulating wire.

[0057] Comparative Example 2: The difference from Example 1 is that in S4, nano-zinc oxide and graphene nanosheets are used to replace zinc oxide / graphene nanosheets, obtaining a dispersion with a graphene nanosheet concentration of 100 g / mL and a nano-zinc oxide concentration of 20 mg / mL, and the remaining steps remain unchanged, obtaining a three-layer insulating wire.

[0058] Comparative Example 3: The difference from Example 1 is that in S6, 2 g of modified graphene oxide composite glass fiber and 18 g of bisphenol A epoxy resin are used to replace the reinforced epoxy resin powder, and the remaining steps remain unchanged, obtaining a three-layer insulating wire.

[0059] Some reagent parameters in the examples and comparative examples are as follows:

[0060] The particle size of graphene oxide nanosheets is 0.5 - 5 μm, and the thickness is 0.8 - 1 nm.

[0061] The type of bisphenol A epoxy resin is E-03.

[0062] The glass fiber is chopped glass fiber with a diameter of 9 - 12 μm and a length of 0.5 - 1 mm.

[0063] Perform performance tests on the three-layer insulated wires prepared in Examples 1 - 3 and Comparative Examples 1 - 3. The tests are carried out according to the standard UL 2353-2016. Use a withstand voltage tester to test the withstand voltage strength of the specimens, adopting the steel ball method with a leakage current of 5 mA; according to the standard GB / T2951.11-2008, test the tensile strength and elongation at break of the specimens, and test the tensile strength and elongation at break after the specimens are aged under ultraviolet light for 720 h (argon arc lamp), and calculate the tensile strength retention rate and elongation at break retention rate.

[0064] The results are shown in Table 1 as follows:

[0065] Table 1: Performance test results table of three-layer insulated wire

[0066]

[0067]

[0068] It can be seen from Table 1 that the three-layer insulated wire prepared by the present invention has a high withstand voltage strength, good performance, relatively high tensile strength and elongation at break, and high tensile strength retention rate and elongation at break retention rate after ultraviolet aging, indicating that the three-layer insulated wire prepared by the present invention has strong aging resistance, is not easy to crack, and has high toughness.

[0069] In Comparative Example 1, since MOF was not synthesized on the surface of carboxylated glass fiber, the hydrogen bond binding ability between carboxylated glass fiber and zinc oxide / graphene nanosheets was weak, the dispersibility of zinc oxide graphene nanosheets decreased, and in the prepared reinforced epoxy resin powder, the binding force between modified graphene oxide composite glass fiber and epoxy resin decreased, resulting in a decrease in the mechanical strength of the three-layer insulated wire and a weakening of the aging resistance performance.

[0070] In Comparative Example 2, since the anti-ultraviolet fillers nano-zinc oxide and graphene nanosheets were added separately, nano-zinc oxide was prone to agglomeration, and the synergistic anti-ultraviolet performance with graphene nanosheets decreased, resulting in a weakening of both mechanical strength and anti-aging performance.

[0071] In Comparative Example 3, since the modified graphene oxide composite glass fiber was directly added to the polybutylene terephthalate and polyethylene terephthalate matrixes, the compatibility between the modified graphene oxide composite glass fiber and the matrix was poor, resulting in a decrease in the mechanical strength of the three-layer insulated wire and a weak anti-aging performance.

[0072] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. A three-layer insulated wire resistant to aging and cracking, which is composed of a copper wire, an inner insulating layer, an intermediate insulating layer and an outer protective layer from inside to outside, and is characterized in that, The inner insulating layer and the intermediate insulating layer are made of insulating layer rubber compound. The insulating layer rubber compound, by mass parts, comprises the following components: 10-15 parts of polybutylene terephthalate, 40-50 parts of polyethylene terephthalate, 20-30 parts of reinforced epoxy resin powder, 3-5 parts of color masterbatch, and 10-15 parts of thermoplastic polyester elastomer; The reinforced epoxy resin powder is prepared by the following steps: Step 1: In a reaction kettle, zinc oxide / graphene nanosheets and MOF composite glass fibers are compounded under the action of 3-mercaptopropyltrimethoxysilane to obtain modified graphene oxide composite glass fibers; Step 2: In a reaction kettle, bisphenol A epoxy resin and isopropanol are heated and stirred to dissolve, modified graphene oxide composite glass fibers and tetramethylammonium chloride are added, heated to 60-80 °C and stirred for reaction for 4-6 h, the solvent is removed by rotary evaporation, then dried, crushed, and sieved through a 200-mesh sieve to obtain reinforced epoxy resin powder.

2. The three-layer insulated wire resistant to aging and cracking according to claim 1, characterized in that In Step 2, the dosage ratio of bisphenol A epoxy resin, isopropanol, modified graphene oxide composite glass fibers, and tetramethylammonium chloride is 20-30 g: 10-15 mL: 2-3 g: 0.2-0.3 g.

3. The three-layer insulated wire with anti-aging cracking according to claim 1, characterized in that, The modified graphene oxide composite glass fibers in Step 1 are specifically prepared by the following steps: In a reaction kettle, MOF composite glass fibers and a dispersion liquid are mixed in the reaction kettle, 3-mercaptopropyltrimethoxysilane is added, oscillated for 20-24 h, the precipitate is filtered, the precipitate is washed, and dried to obtain modified graphene oxide composite glass fibers.

4. A three-layer insulated wire resistant to aging and cracking according to claim 3, characterized in that, The dosage ratio of the MOF composite glass fibers, the dispersion liquid, and 3-mercaptopropyltrimethoxysilane is 2-3 g: 2-3 L: 1-2 g; the concentration of the dispersion liquid is 100 mg / L, which is prepared by ultrasonically dispersing zinc oxide / graphene nanosheets in a 50 wt% ethanol aqueous solution.

5. The three-layer insulated wire with anti-aging cracking according to claim 4, characterized in that, The MOF composite glass fibers are prepared by the following steps: In a reaction kettle, ferric chloride hexahydrate is dissolved in deionized water, acetic acid is added, stirred for 2-3 h, 2-aminoterephthalic acid is added and stirred for another 2-3 h, then carboxylated glass fibers are added to the reaction kettle, heated to 120-130 °C and reacted for 20-24 h, the precipitate is filtered, the precipitate is washed, and vacuum dried to obtain MOF composite glass fibers.

6. The three-layer insulated wire resistant to aging and cracking according to claim 5, wherein, The dosage ratio of ferric chloride hexahydrate, deionized water, acetic acid, 2-aminoterephthalic acid, and carboxylated glass fibers is 2-2.5 g: 150-180 mL: 5-6 mL: 0.8-1.2 g: 1-1.5 g.

7. The three-layer insulated wire with anti-aging and anti-cracking properties according to claim 6, characterized in that, The carboxylated glass fibers are prepared by the following steps: In a reaction kettle, glass fibers are ultrasonically dispersed in DMF, silane coupling agent APTES and a 4-5 wt% succinic anhydride DMF solution are added to the reaction kettle, stirred for 20-24 h, the precipitate is centrifugally collected, the precipitate is washed, and dried to obtain carboxylated glass fibers; The dosage ratio of the glass fibers, DMF, silane coupling agent APTES, and succinic anhydride DMF solution is 10-15 g: 500-600 mL: 3-4 g: 100-150 mL.

8. A three-layer insulated wire resistant to aging and cracking according to claim 4, characterized in that, The zinc oxide / graphene nanosheets are prepared by the following steps: Thermally reduce graphene oxide nanosheets to obtain reduced graphene oxide. Ultrasonically disperse the reduced graphene oxide in deionized water in a reaction kettle, add 1M zinc acetate solution and 1M ammonia water, ultrasonically treat for 30 - 40 min, then heat up to 170 - 180 °C and react for 20 - 24 h. Centrifuge to collect the precipitate, wash the precipitate, and vacuum dry to obtain zinc oxide / graphene nanosheets.

9. A three-layer insulated wire resistant to aging and cracking according to claim 8, characterized in that, The dosage ratio of the reduced graphene oxide, deionized water, zinc acetate solution, and ammonia water is 5 - 8 g : 500 - 800 mL : 20 - 30 mL : 30 - 40 mL.

10. The preparation method of a three-layer insulated wire resistant to aging and cracking according to claim 1, characterized in that, Including the following steps: Mix polybutylene terephthalate, polyethylene terephthalate, reinforced epoxy resin powder, color masterbatch, and thermoplastic polyester elastomer, then bake in an oven at 120 - 130 °C for 5 - 6 h, transfer to a feeding hopper for discharging. After the discharged compound is delicate and free of granularity, obtain the insulating layer compound; use a three-layer insulated wire tandem extrusion production line to co-extrude an insulating layer and a protective layer with a copper wire. The copper wire is the core, nylon is the protective layer, and the insulating layer compound is the inner insulating layer and the middle insulating layer to obtain a three-layer insulated wire with anti-aging and cracking resistance.

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