Environment-friendly polypropylene insulated power cable and preparation process thereof

Abstract

The invention provides an environment-friendly polypropylene insulated power cable and a preparation process thereof, and belongs to the technical field of cable preparation. The preparation process comprises the following steps: preparing hydrophobic hybrid particles; preparing the hydrophobic anti-icing coating; double modification of hexagonal boron nitride; preparing an insulated cable material; and preparing the power cable. The cable prepared by the invention has good insulating property, the tensile strength can be improved, the service life of the cable can be prolonged, the cable has a remarkable super-hydrophobic effect after being sprayed with the hydrophobic anti-icing coating, the service time of the cable in a low-temperature and high-relative-humidity environment can be prolonged, icing can be avoided, and the use safety of the cable can be ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of cable preparation, and particularly relates to an environment-friendly polypropylene insulated power cable and a preparation process thereof. Background Art

[0002] With the adjustment of the global energy structure and the rapid growth of power transmission demand, power cables, as the core carriers of electric energy transmission, have received extensive attention for their performance and environmental friendliness. Traditional power cable insulation materials mostly use polyvinyl chloride (PVC) or cross-linked polyethylene (XLPE), but such materials have significant defects: PVC will release a large amount of halogen-containing toxic gases when burned, while the production process of XLPE relies on chemical cross-linking technology, which has problems such as high energy consumption and difficult degradation of cross-linking by-products. In recent years, polypropylene (PP) has been regarded as an ideal alternative to environmentally friendly insulation materials due to its excellent high-temperature resistance, mechanical strength, and recyclable characteristics.

[0003] Although polypropylene has many advantages as an insulation material, there are still some technical problems to be solved in the process of applying it to power cables: when polypropylene materials are used as cable insulation materials, they have the disadvantage of insufficient flexibility, which cannot meet the requirements of cable laying, installation, and production, resulting in their inability to be directly used, and they must be toughened and modified. Currently, the most common method for modifying polypropylene is to physically modify it by melt blending thermoplastic elastomer and polypropylene. When the heat generated by the blended toughened polypropylene cable insulation material during long-term operation is difficult to effectively dissipate, the high-temperature environment will accelerate the aging of the insulation layer and shorten the service life of the cable. On the other hand, when the cable operates outdoors, especially in environments with low temperature and high relative humidity in the north, icing and condensation are likely to occur on the surface. This will not only increase the weight of the cable but may also damage the insulation performance and mechanical performance of the cable. Most of the existing technologies solve the problems of icing and condensation by forming a superhydrophobic coating on the cable surface. However, the comprehensive performance of most of the superhydrophobic coatings reported in the current literature is poor, and the bonding force between the coating and the cable is poor. Therefore, a binder will be added, and the introduction of the binder usually embeds low-surface-energy nanoparticles, thus significantly increasing the surface energy of the coating and reducing the hydrophobicity.

[0004] Therefore, aiming at the problems existing in the above-mentioned prior art, it is urgent to develop an environment-friendly polypropylene insulated power cable and a preparation process thereof that can effectively improve the insulation reliability, thermal conductivity, and superhydrophobic anti-icing performance of polypropylene insulated cables. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an environment-friendly polypropylene insulated power cable and a preparation process thereof.

[0006] An environmentally friendly polypropylene insulated power cable includes, from the inside to the outside, a conductor, a shielding layer, an insulating layer, a sheath layer, and a hydrophobic anti-icing protective layer. The insulating cable material is extruded outside the shielding layer to obtain the insulating layer. The insulating cable material includes 30-40 parts by weight of MAH-grafted polypropylene resin, 23-34 parts by weight of ethylene-propylene copolymer, 15-20 parts by weight of hydrogenated styrene-butadiene-styrene block copolymer, 2-3 parts by weight of compatibilizer, and 5-8 parts by weight of double-modified hexagonal boron nitride; The hydrophobic anti-icing coating is sprayed outside the sheath layer to form a hydrophobic anti-icing protective layer. The hydrophobic anti-icing coating includes 53-68 parts by weight of a semi-solid centrifuge containing ethanol, 28-29 parts by weight of ethanol, 1-1.2 parts by weight of ultraviolet absorber, and 0.8-1 part by weight of antioxidant; The semi-solid centrifuge containing ethanol is obtained by adding MOFs@hydrophobic hybrid particle nanoparticles to a mixed solution of ethanol, deionized water, and 28wt% ammonia water, and then adding perfluorodecyltriethoxysilane and tetraethyl orthosilicate and stirring and centrifuging; The hydrophobic hybrid particles are prepared by wrapping lignin-calcium carbonate composite powder with chitosan.

[0007] A preparation process of an environmentally friendly polypropylene insulated power cable includes the following steps: S1: Preparation of hydrophobic hybrid particles S2: Preparation of hydrophobic anti-icing coating Mix copper nitrate, 2,3,6,7,10,11-hexahydroxy triphenylene hydrate, and N,N-dimethylformamide aqueous solution, then add hydrophobic hybrid particles to prepare MOFs@hydrophobic hybrid particle nanoparticles, and then add MOFs@hydrophobic hybrid particle nanoparticles to the mixed solution, and then add perfluorodecyltriethoxysilane and tetraethyl orthosilicate to react, and then mix and react with silicon-modified polyester, dimethyl carbonate, and ethanol to prepare a hydrophobic anti-icing coating; S3: Double modification of hexagonal boron nitride Use thionyl chloride to etch and modify hexagonal boron nitride, and then use succinic acid for modification to prepare double-modified hexagonal boron nitride; S4: Preparation of insulating cable material S5: Preparation of power cable Wrap the shielding layer on the surface of the conductor material, and then wrap the insulating layer to obtain a core. Wrap the sheath layer on the surface of the core, and spray the hydrophobic anti-icing coating on the surface of the sheath layer to obtain a power cable.

[0008] Further, the preparation of the hydrophobic hybrid particles in step S1 specifically includes the following steps: S1.1: Add 1.23 - 1.32 parts by weight of lignin to 60 - 80 parts by weight of tetrahydrofuran, then stir and mix at 600 - 700 r / min for 20 - 30 min to obtain a lignin - tetrahydrofuran mixed solution. Add 0.9 - 1.2 parts by weight of chitosan to 90 - 100 parts by weight of 0.1 M acetic acid, stir and mix for 2 - 3 h to obtain a chitosan solution; S1.2: Add 0.6 - 0.8 parts by weight of calcium carbonate to 20 - 30 parts by weight of deionized water, disperse for 10 - 20 min, then drop the calcium carbonate suspension into the lignin - tetrahydrofuran mixed solution at a dropping rate of 20 - 30 mL / min. Then stir in a fume hood until the tetrahydrofuran completely volatilizes, and then perform freeze - drying to obtain lignin - calcium carbonate composite powder; S1.3: Add 2 - 3 parts by weight of lignin - calcium carbonate composite powder to 8 - 10 parts by weight of deionized water to obtain a lignin - calcium carbonate suspension. Then add the lignin - calcium carbonate suspension to the chitosan solution, and then adjust the pH to neutral, stir and react for 2 - 3 h, and then perform freeze - drying to obtain hydrophobic hybrid microparticles.

[0009] Further, the preparation of the hydrophobic anti - icing coating in step S2 specifically includes the following steps: S2.1: Add 9.7 - 10.2 parts by weight of copper nitrate and 6.5 - 8 parts by weight of 2,3,6,7,10,11 - hexahydroxytriphenylene hydrate to a mixed solution of 1000 - 1200 parts by weight of N,N - dimethylformamide and deionized water. N,N - dimethylformamide and deionized water are mixed in a volume ratio of 1:9 - 10. Then stir for 10 - 20 min, add 25 - 38 parts by weight of hydrophobic hybrid microparticles, and then stir and react at 85 - 90 °C and 500 - 600 r / min for 15 - 18 h. Then filter and dry to obtain MOFs@hydrophobic hybrid microparticle nanoparticles; S2.2: Mix ethanol, deionized water, and 28 wt% ammonia water in a volume ratio of (75 - 78):(23 - 25):(2 - 3) to obtain a mixed solution. Add 10 - 12 parts by weight of MOFs@hydrophobic hybrid microparticle nanoparticles to 500 - 520 parts by weight of the mixed solution, stir for 10 - 12 min, then perform ultrasonic treatment for 5 - 8 min, and then add 8 - 10 parts by weight of perfluorodecyltriethoxysilane and 1 - 2 parts by weight of tetraethyl orthosilicate, stir at room temperature for 2 - 3 h, and then centrifuge to obtain a semi - solid centrifuge body containing ethanol; S2.3: Add 2 - 3 parts by weight of silicon - modified polyester into 100 - 120 parts by weight of dimethyl carbonate, then add 53 - 68 parts by weight of a semi - solid centrifuge containing ethanol, stir and react for 1 - 2 h, then add 28 - 29 parts by weight of ethanol, then stir at 3000 - 5000 r / min for 3 - 4 h, and finally add 1 - 1.2 parts by weight of ultraviolet absorber UV - 1130 and 0.8 - 1 part by weight of antioxidant 1010, stir and mix for 1 - 2 h to obtain a hydrophobic anti - icing coating.

[0010] Further, the double modification of hexagonal boron nitride in step S3 specifically includes the following steps: S3.1: Add 15 - 18 parts by weight of chloroform and 30 - 35 parts by weight of thionyl chloride to 5 - 8 parts by weight of hexagonal boron nitride, stir and mix at 200 - 300 r / min for 30 - 40 min, then perform ultrasonic treatment for 10 - 12 min, and finally stir and react at 500 - 800 r / min at room temperature for 48 - 50 h, then centrifuge, wash, and dry to obtain etched - modified hexagonal boron nitride; S3.2: Add 3 - 5 parts by weight of etched - modified hexagonal boron nitride and 1.2 - 1.8 parts by weight of succinic acid into 50 - 60 parts by weight of toluene, perform ultrasonic dispersion at 50 - 80 W for 20 - 30 min, then place it in a flask equipped with a stirrer and a condenser, react at 110 - 120 °C for 8 - 10 h, then filter, and then wash and filter with absolute ethanol 2 - 3 times, and dry to obtain double - modified hexagonal boron nitride.

[0011] Further, the preparation of the insulating cable material in step S4 specifically includes the following steps: S4.1: Add 40 - 50 parts by weight of polypropylene resin into a torque rheometer at 180 - 185 °C, then knead at 60 - 80 rpm for 3 - 5 min, then add a styrene derivative with a mass fraction of 1 - 2%, knead for 3 - 5 min, then add MAH with a mass fraction of 3 - 5%, knead for 3 - 5 min, and finally add diisopropylbenzene peroxide with a mass fraction of 0.025 - 0.028% and knead for 10 - 12 min to obtain MAH - grafted modified polypropylene resin; S4.2: Mix 30 - 40 parts by weight of MAH - grafted modified polypropylene resin, 23 - 34 parts by weight of ethylene - propylene copolymer, 15 - 20 parts by weight of hydrogenated styrene - butadiene - styrene block copolymer, 2 - 3 parts by weight of PE - g - GMA compatibilizer, and 5 - 8 parts by weight of double - modified hexagonal boron nitride, and then perform ultrasonic oscillation for 20 - 30 min to obtain an insulating cable material.

[0012] Further, the preparation of the power cable in step S5 specifically includes the following steps: S5.1: After wrapping the shielding layer around the conductor to form the shielding layer, at 160 - 180 °C and 15 - 20 MPa, the insulating cable material is melt-extruded to wrap it on the surface of the shielding layer, obtaining a core; S5.2: Extrude polyvinyl chloride on the surface of the core to form a sheath layer, spray a hydrophobic anti-icing coating on the sheath layer, with a spraying distance of 200 - 300 mm, the film thickness controlled at 20 - 30 μm, and cured at room temperature for 24 - 28 h to obtain a power cable.

[0013] Furthermore, in step S4.2, the compatibilizer is a PE-g-GMA compatibilizer.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: 1. Through the treatment with thionyl chloride, more amino and hydroxyl groups are introduced on the surface of hexagonal boron nitride in the present invention, increasing the surface active groups, reducing the van der Waals force between nanosheets, inhibiting agglomeration, improving its dispersion in the matrix, and then performing succinic acid modification to make its surface rougher, so that there can be a strong interfacial interaction with the substrate, and the load can be transmitted more effectively under external force, reducing the debonding or cracking between the filler and the matrix, thereby improving the tensile strength and extending the service life of the cable. Adding the doubly modified hexagonal boron nitride can effectively inhibit the accumulation of space charge, greatly improve the DC breakdown strength, reduce the risk of electrical breakdown, and improve the insulation reliability. Moreover, hexagonal boron nitride itself has high thermal conductivity, and after uniform dispersion by modification, it can form an efficient thermal conduction network in the polypropylene matrix, accelerating the dissipation of heat during the operation of the cable and reducing the aging effect of long-term high temperature on the insulation layer.

[0015] 2. In the present invention, lignin molecules are aggregated through the π-π and hydrogen bond interactions between lignin molecules, precipitated and tightly coated on the surface of calcium carbonate particles, and then chitosan is introduced. Since lignin is negatively charged and chitosan is positively charged, chitosan can be attached to the surface of the lignin-calcium carbonate composite powder through electrostatic interaction, thereby improving stability and enhancing its rough structure, significantly increasing the water contact angle of the coating, achieving superhydrophobic properties, and the rough structure is conducive to the subsequent in-situ growth of metal-organic framework compounds. Then, modification with perfluorodecyltriethoxysilane and tetraethyl orthosilicate further improves the superhydrophobic effect. The metal-organic framework compounds can effectively absorb light and convert it into heat, and the coating has many photothermal traps that can effectively capture sunlight. The light is trapped in the light trap, resulting in multiple internal reflections until it is completely absorbed, improving the photothermal conversion performance and achieving an anti-icing effect. Thus, the coating has photothermal conversion performance and superhydrophobic properties, can extend the service time of the cable in low-temperature and high relative humidity environments, avoid icing, and ensure the safety of cable use.

[0016] 3. In the present invention, a silicon-modified polyester binder is added during the preparation of the coating. The silicon-modified polyester binder can enhance the bonding force between the coating and the substrate and the bonding force between the semi-solid centrifugates in the coating, thereby improving the mechanical stability and strength of the coating, and then enhancing the mechanical strength of the cable. Moreover, the addition of the silicon-modified polyester binder and the adjustment of the ethanol addition content can achieve phase separation, enabling the semi-solid centrifugates to wrap around the silicon-modified polyester binder particles, thus not affecting the hydrophobic performance. After the coating is cured, under the adhesion of the silicon-modified polyester, micro-aggregates composed of silicon-modified polyester binder particles and semi-solid centrifugates are formed, which can significantly improve the wear resistance of the coating and extend the service life of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings incorporated herein and constituting a part of the specification illustrate embodiments of the present invention and, together with the specification, are further used to explain the principles of the present invention and enable those skilled in the relevant art to implement and use the present invention.

[0018] Figure 1 SEM image of the hydrophobic hybrid particles of the embodiment of the present invention; Figure 2 SEM image of the double-modified hexagonal boron nitride of the embodiment of the present invention; Figure 3 SEM image of unmodified hexagonal boron nitride. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The preparation process of an environmentally friendly polypropylene-insulated power cable provided by the present invention will be described in detail below in conjunction with the drawings and specific embodiments. At the same time, it should be noted here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments. For some well-known technologies, those skilled in the art can also adopt other alternative methods for implementation; moreover, the drawing part is only for more specifically describing the embodiments and is not intended to specifically limit the present invention.

[0020] In the following embodiments and comparative examples: The conductor consists of an inner core layer and an outer core layer from the inside to the outside. The inner core layer is composed of seven aluminum alloy wires with equal diameters, and the outer core layer is composed of twelve aluminum alloy wires with equal diameters.

[0021] Example 1 A preparation process of an environmentally friendly polypropylene-insulated power cable includes the following steps: S1: Preparation of hydrophobic hybrid particles S1.1: Add 1.23 parts by weight of lignin to 60 parts by weight of tetrahydrofuran, and then stir and mix at 600 r / min for 20 min to obtain a lignin-tetrahydrofuran mixed solution. Add 0.9 part by weight of chitosan to 90 parts by weight of 0.1 M acetic acid, stir and mix for 2 h to obtain a chitosan solution; S1.2: Add 0.6 part by weight of calcium carbonate to 20 parts by weight of deionized water, disperse for 10 min, and then drop the calcium carbonate suspension into the lignin-tetrahydrofuran mixed solution at a dropping rate of 20 mL / min. Then stir in a fume hood until the tetrahydrofuran completely evaporates, and then perform freeze-drying to obtain lignin-calcium carbonate composite powder; S1.3: Add 2 parts by weight of lignin-calcium carbonate composite powder to 8 parts by weight of deionized water to obtain a lignin-calcium carbonate suspension. Then add the lignin-calcium carbonate suspension to the chitosan solution, and then adjust the pH to neutral, stir and react for 2 h, and then perform freeze-drying to obtain hydrophobic hybrid particles; S2: Preparation of hydrophobic anti-icing coating S2.1: Add 9.7 parts by weight of copper nitrate and 6.5 parts by weight of 2,3,6,7,10,11-hexahydroxytriphenylene hydrate to a mixed solution of 1000 parts by weight of N,N-dimethylformamide and deionized water. N,N-dimethylformamide and deionized water are mixed according to a volume ratio of 1:9. Then stir for 10 min, add 25 parts by weight of hydrophobic hybrid particles, and then stir and react at 85 °C and 500 r / min for 15 h. Then filter and dry to obtain MOFs@hydrophobic hybrid particle nanoparticles; S2.2: Mix ethanol, deionized water, and 28 wt% ammonia water according to a volume ratio of 75:23:2 to obtain a mixed solution. Add 10 parts by weight of MOFs@hydrophobic hybrid particle nanoparticles to 500 parts by weight of the mixed solution, stir for 10 min, then perform ultrasonic treatment for 5 min, and then add 8 parts by weight of perfluorodecyltriethoxysilane and 1 part by weight of tetraethyl orthosilicate, stir at room temperature for 2 h, and then centrifuge to obtain a semi-solid centrifuge containing ethanol; S2.3: Add 2 parts by weight of silicon-modified polyester to 100 parts by weight of dimethyl carbonate, then add 53 parts by weight of the semi-solid centrifuge containing ethanol, stir and react for 1 h, then add 28 parts by weight of ethanol, then stir at 3000 r / min for 3 h, and finally add 1 part by weight of ultraviolet absorber UV-1130 and 0.8 part by weight of antioxidant 1010, stir and mix for 1 h to obtain a hydrophobic anti-icing coating; S3: Double modification of hexagonal boron nitride S3.1: Add 15 parts by weight of chloroform and 30 parts by weight of thionyl chloride to 5 parts by weight of hexagonal boron nitride. Stir and mix at 200 r / min for 30 min, then perform ultrasonic treatment for 10 min. Finally, stir and react at 500 r / min at room temperature for 48 h, then centrifuge, wash, and dry to obtain etched and modified hexagonal boron nitride; S3.2: Add 3 parts by weight of etched and modified hexagonal boron nitride and 1.2 parts by weight of succinic acid to 50 parts by weight of toluene. Disperse ultrasonically at 50 W for 20 min, then place it in a flask equipped with a stirrer and a condenser, react at 110 °C for 8 h, then filter, and then wash and filter with absolute ethanol twice and dry to obtain doubly modified hexagonal boron nitride; S4: Preparation of insulating cable material S4.1: Add 40 parts by weight of polypropylene resin to a 180 °C torque rheometer, then knead at 60 rpm for 3 min, then add a styrene derivative with a mass fraction of 1%, knead for 3 min, then add MAH with a mass fraction of 3%, knead for 3 min, and finally add diisopropylbenzene peroxide with a mass fraction of 0.025% and knead for 10 min to obtain MAH-grafted modified polypropylene resin; S4.2: Mix 30 parts by weight of MAH-grafted modified polypropylene resin, 23 parts by weight of ethylene-propylene copolymer, 15 parts by weight of hydrogenated styrene-butadiene-styrene block copolymer, 2 parts by weight of PE-g-GMA compatibilizer, and 5 parts by weight of doubly modified hexagonal boron nitride, and then perform ultrasonic oscillation for 20 min to obtain an insulating cable material; S5: Preparation of power cable S5.1: After covering the copper tape braided shielding layer outside the conductor to form a shielding layer, at 160 °C and 15 MPa, melt and extrude the insulating cable material so that it wraps on the surface of the shielding layer to obtain a core; S5.2: Extrude polyvinyl chloride on the surface of the core to form a sheath layer, spray a hydrophobic anti-icing coating on the sheath layer, the spraying distance is 200 mm, the film thickness is controlled at 20 μm, and cure at room temperature for 24 h to obtain a power cable.

[0022] Example 2 A preparation process of an environmentally friendly polypropylene insulated power cable, comprising the following steps: S1: Preparation of hydrophobic hybrid particles S1.1: Add 1.32 parts by weight of lignin to 80 parts by weight of tetrahydrofuran, then stir and mix at 600 r / min for 20 min to obtain a lignin-tetrahydrofuran mixed solution. Add 1.2 parts by weight of chitosan to 100 parts by weight of 0.1 M acetic acid, stir and mix for 2 h to obtain a chitosan solution; S1.2: Add 0.8 parts by weight of calcium carbonate to 30 parts by weight of deionized water, disperse for 10 min, then drop the calcium carbonate suspension into the lignin-tetrahydrofuran mixture at a dropping rate of 20 mL / min. Then stir in a fume hood until the tetrahydrofuran completely evaporates, and then perform freeze-drying to obtain lignin-calcium carbonate composite powder; S1.3: Add 3 parts by weight of lignin-calcium carbonate composite powder to 10 parts by weight of deionized water to obtain a lignin-calcium carbonate suspension. Then add the lignin-calcium carbonate suspension to the chitosan solution, and then adjust the pH to neutral. Stir and react for 2 h, and then perform freeze-drying to obtain hydrophobic hybrid particles; S2: Preparation of hydrophobic anti-icing coating S2.1: Add 10.2 parts by weight of copper nitrate and 8 parts by weight of 2,3,6,7,10,11-hexahydroxytriphenylene hydrate to a mixed solution of 1200 parts by weight of N,N-dimethylformamide and deionized water. N,N-dimethylformamide and deionized water are mixed in a volume ratio of 1:10. Then stir for 10 min, add 38 parts by weight of hydrophobic hybrid particles, and then stir and react at 85 °C and 500 r / min for 15 h. Then filter and dry to obtain MOFs@hydrophobic hybrid particle nanoparticles; S2.2: Mix ethanol, deionized water, and 28 wt% ammonia water in a volume ratio of 78:25:3 to obtain a mixed solution. Add 12 parts by weight of MOFs@hydrophobic hybrid particle nanoparticles to 520 parts by weight of the mixed solution, stir for 10 min, then perform ultrasonic treatment for 5 min, and then add 10 parts by weight of perfluorodecyltriethoxysilane and 2 parts by weight of tetraethyl orthosilicate. Stir at room temperature for 2 h, and then centrifuge to obtain a semi-solid centrifuge containing ethanol; S2.3: Add 3 parts by weight of silicon-modified polyester to 120 parts by weight of dimethyl carbonate, then add 68 parts by weight of the semi-solid centrifuge containing ethanol, stir and react for 1 h, then add 29 parts by weight of ethanol, and then stir at 3000 r / min for 3 h. Finally, add 1.2 parts by weight of ultraviolet absorber UV-1130 and 1 part by weight of antioxidant 1010, and stir and mix for 1 h to obtain a hydrophobic anti-icing coating; S3: Double modification of hexagonal boron nitride S3.1: Add 18 parts by weight of chloroform and 35 parts by weight of thionyl chloride to 8 parts by weight of hexagonal boron nitride, stir and mix at 200 r / min for 30 min, then perform ultrasonic treatment for 10 min, and finally stir and react at 500 r / min at room temperature for 48 h. Then centrifuge, wash, and dry to obtain etched modified hexagonal boron nitride; S3.2: Add 5 parts by weight of etched and modified hexagonal boron nitride and 1.8 parts by weight of succinic acid to 60 parts by weight of toluene, disperse ultrasonically at 50 W for 20 min, then place it in a flask equipped with a stirring and condensing device, react at 110 °C for 8 h, then filter, and then wash and filter with absolute ethanol twice, and dry to obtain doubly modified hexagonal boron nitride; S4: Preparation of insulating cable material S4.1: Add 50 parts by weight of polypropylene resin to a 180 °C torque rheometer, then knead at 60 rpm for 3 min, then add a styrene derivative with a mass fraction of 2%, knead for 3 min, then add MAH with a mass fraction of 5%, knead for 3 min, and finally add diisopropylbenzene peroxide with a mass fraction of 0.028% and knead for 10 min to obtain MAH-grafted modified polypropylene resin; S4.2: Mix 40 parts by weight of MAH-grafted modified polypropylene resin, 34 parts by weight of ethylene-propylene copolymer, 20 parts by weight of hydrogenated styrene-butadiene-styrene block copolymer, 3 parts by weight of PE-g-GMA compatibilizer and 8 parts by weight of doubly modified hexagonal boron nitride, and then perform ultrasonic oscillation for 20 min to obtain insulating cable material; S5: Preparation of power cable S5.1: After covering the copper tape braided shielding layer outside the conductor to form a shielding layer, at 160 °C and 15 MPa, melt-extrude the insulating cable material so that it wraps on the surface of the shielding layer to obtain a wire core; S5.2: Extrude polyvinyl chloride on the surface of the wire core to form a sheath layer, spray a hydrophobic anti-icing coating on the sheath layer, the spraying distance is 200 mm, the film thickness is controlled at 20 μm, and cure at room temperature for 24 h to obtain a power cable.

[0023] Example 3 A preparation process of an environmentally friendly polypropylene insulated power cable includes the following steps: S1: Preparation of hydrophobic hybrid particles S1.1: Add 1.23 parts by weight of lignin to 60 parts by weight of tetrahydrofuran, then stir and mix at 700 r / min for 30 min to obtain a lignin-tetrahydrofuran mixture, add 0.9 parts by weight of chitosan to 90 parts by weight of 0.1 M acetic acid, and stir and mix for 3 h to obtain a chitosan solution; S1.2: Add 0.6 parts by weight of calcium carbonate to 20 parts by weight of deionized water, disperse for 20 min, then drop the calcium carbonate suspension into the lignin-tetrahydrofuran mixture at a dropping rate of 30 mL / min, then stir in a fume hood until the tetrahydrofuran completely volatilizes, and then perform freeze-drying to obtain lignin-calcium carbonate composite powder; S1.3: Add 2 parts by weight of lignin-calcium carbonate composite powder to 8 parts by weight of deionized water to obtain a lignin-calcium carbonate suspension. Then add the lignin-calcium carbonate suspension to the chitosan solution, and then adjust the pH to neutral. Stir and react for 3 h, and then freeze-dry to obtain hydrophobic hybrid particles; S2: Preparation of Hydrophobic Anti-Icing Coating S2.1: Add 9.7 parts by weight of copper nitrate and 6.5 parts by weight of 2,3,6,7,10,11-hexahydroxytriphenylene hydrate to a mixed solution of 1000 parts by weight of N,N-dimethylformamide and deionized water. N,N-dimethylformamide and deionized water are mixed in a volume ratio of 1:9. Then stir for 20 min, add 25 parts by weight of hydrophobic hybrid particles, and then stir and react at 90 °C and 600 r / min for 18 h. Then filter and dry to obtain MOFs@hydrophobic hybrid particle nanoparticles; S2.2: Mix ethanol, deionized water, and 28 wt% ammonia water in a volume ratio of 75:23:2 to obtain a mixed solution. Add 10 parts by weight of MOFs@hydrophobic hybrid particle nanoparticles to 500 parts by weight of the mixed solution, stir for 12 min, then ultrasonically treat for 8 min, then add 8 parts by weight of perfluorodecyltriethoxysilane and 1 part by weight of tetraethyl orthosilicate, and stir at room temperature for 3 h. Then centrifuge to obtain a semi-solid centrifuge containing ethanol; S2.3: Add 2 parts by weight of silicon-modified polyester to 100 parts by weight of dimethyl carbonate, then add 53 parts by weight of the semi-solid centrifuge containing ethanol, stir and react for 2 h, then add 28 parts by weight of ethanol, then stir at 5000 r / min for 4 h, and finally add 1 part by weight of ultraviolet absorber UV-1130 and 0.8 part by weight of antioxidant 1010, and stir and mix for 2 h to obtain a hydrophobic anti-icing coating; S3: Dual Modification of Hexagonal Boron Nitride S3.1: Add 15 parts by weight of chloroform and 30 parts by weight of thionyl chloride to 5 parts by weight of hexagonal boron nitride, stir and mix at 300 r / min for 40 min, then ultrasonically treat for 12 min, and finally stir and react at 800 r / min at room temperature for 50 h. Then centrifuge, wash, and dry to obtain etched modified hexagonal boron nitride; S3.2: Add 3 parts by weight of etched modified hexagonal boron nitride and 1.2 parts by weight of succinic acid to 50 parts by weight of toluene, ultrasonically disperse at 80 W for 30 min, then place in a flask with a stirring and condensing device, react at 120 °C for 10 h, then filter, and then wash and filter with anhydrous ethanol 3 times and dry to obtain dual-modified hexagonal boron nitride; S4: Preparation of Insulated Cable Material S4.1: Add 40 parts by weight of polypropylene resin to a 185°C torque rheometer, then knead for 5 min at 80 rpm, then add a styrene derivative with a mass fraction of 1%, knead for 5 min, then add MAH with a mass fraction of 3%, knead for 5 min, and finally add diisopropylbenzene peroxide with a mass fraction of 0.025% and knead for 12 min to obtain MAH-grafted modified polypropylene resin; S4.2: Mix 30 parts by weight of MAH-grafted modified polypropylene resin, 23 parts by weight of ethylene-propylene copolymer, 15 parts by weight of hydrogenated styrene-butadiene-styrene block copolymer, 2 parts by weight of PE-g-GMA compatibilizer and 5 parts by weight of double-modified hexagonal boron nitride, and then perform ultrasonic oscillation for 30 min to obtain an insulating cable material; S5: Preparation of power cable S5.1: After covering the copper tape braided shielding layer outside the conductor to form a shielding layer, at 180°C and 20 MPa, melt-extrude the insulating cable material so that it wraps on the surface of the shielding layer to obtain a wire core; S5.2: Extrude polyvinyl chloride on the surface of the wire core to form a sheath layer, spray a hydrophobic anti-icing coating on the sheath layer, the spraying distance is 300 mm, the film thickness is controlled at 30 μm, and cure at room temperature for 28 h to obtain a power cable.

[0024] Comparative Example 1 Compared with Example 1, the difference in Comparative Example 1 is that Comparative Example 1 removes step S3.2, replaces the double-modified hexagonal boron nitride in step S4.2 with etched modified hexagonal boron nitride, and the remaining steps remain unchanged to prepare a power cable, denoted as Comparative Example 1.

[0025] Comparative Example 2 Compared with Example 1, the difference in Comparative Example 2 is that Comparative Example 2 removes step S3, replaces the double-modified hexagonal boron nitride in step S4.2 with hexagonal boron nitride, and the remaining steps remain unchanged to prepare a power cable, denoted as Comparative Example 2.

[0026] Comparative Example 3 Compared with Example 1, the difference in Comparative Example 3 is that Comparative Example 3 removes steps S1 - S2 and the part of "spray a hydrophobic anti-icing coating on the sheath layer, the spraying distance is 200 mm, the film thickness is controlled at 20 μm, and cure at room temperature for 24 h" in step S5.2. In step S5.2, extrude polyvinyl chloride on the surface of the wire core to form a sheath layer, then a power cable can be prepared, denoted as Comparative Example 3.

[0027] Comparative Example 4 Compared with Example 1, the difference in Comparative Example 4 is that in Comparative Example 4, step S2.3 is removed, and step S2.2 is replaced with "Mix ethanol, deionized water, and 28 wt% ammonia water in a volume ratio of 75:23:2 to obtain a mixed solution. Add 10 parts by weight of MOFs@hydrophobic hybrid particle nanoparticles to 500 parts by weight of the mixed solution, stir for 10 min, then perform ultrasonic treatment for 5 min, then add 8 parts by weight of perfluorodecyltriethoxysilane and 1 part by weight of tetraethyl orthosilicate, stir at room temperature for 2 h, then add 1 part by weight of ultraviolet absorber UV-1130 and 0.8 part by weight of antioxidant 1010, and stir and mix for 1 h to obtain a hydrophobic anti-icing coating". The remaining steps remain unchanged to prepare a power cable, denoted as Comparative Example 4.

[0028] Perform performance tests on the cables prepared in Examples 1-3 and Comparative Examples 1-2, and the test results are shown in Table 1 for reference.

[0029] Table 1. Performance test results of cables in Examples 1-3 and Comparative Examples 1-2

[0030] It can be seen from the data in Table 1 that after adding double-modified hexagonal boron nitride, the tensile strength, elongation at break can be improved, and the DC breakdown strength can be enhanced, its heat conduction ability can be improved, and the aging effect of the long-term high temperature on the insulating layer can be reduced.

[0031] Perform performance tests on the cables prepared in Examples 1-3 and Comparative Examples 3-4, and the test results are shown in Table 2 for reference.

[0032] Table 2. Hydrophobic performance test results of cables in Examples 1-3 and Comparative Examples 3-4

[0033] It can be seen from the data in Table 2 that by spraying the hydrophobic anti-icing coating on the sheath layer of the present invention, the hydrophobic ability of the cable can be significantly improved, and adding the silicon-modified polyester binder in the preparation of the hydrophobic anti-icing coating does not affect the hydrophobic effect of the coating.

[0034] Place the cables prepared in Examples 1-3 and Comparative Example 3 in an environment of -15°C and 80% RH. Place the xenon lamp directly above the sample, and then adjust the xenon lamp to provide stable simulated light (0.1 sun). Record the surface temperature of the sample after 15 min, measure three times, and take the average value. The results are shown in Table 3 for reference.

[0035] Table 3. Surface temperature measurement results of Examples 1-3 and Comparative Example 3

[0036] As can be seen from the data in Table 3, the hydrophobic anti-icing coating prepared by the present invention can exhibit good photothermal conversion performance, can avoid the icing of cables in low-temperature and high-humidity environments, and can improve the service life of cables in cold environments.

[0037] Perform performance tests on the cables prepared in Examples 1-3 and Comparative Example 4, and the test results are shown in Table 4 for reference.

[0038] Abrasion resistance test: According to the Taber friction experiment (125 g load, CS-10 grinding wheel, ASTM D4060), friction for 3000 times and then test the hydrophobic performance again.

[0039] Table 4. Performance test results of Examples 1-3 and Comparative Example 4

[0040] As can be seen from the data in Table 4, adding the silicon-modified polyester binder can improve the tensile strength of the cable, and it still has superhydrophobic performance after the friction experiment, indicating that adding the silicon-modified polyester binder can improve the wear resistance of the coating without affecting the hydrophobic effect.

[0041] From Figure 1 it can be seen that the hydrophobic hybrid microparticle nanoparticles have a rough structure, Figure 2 and Figure 3 it can be seen that compared with the unmodified double-modified hexagonal boron nitride, its surface is rougher.

[0042] The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. An environment-friendly polypropylene insulated power cable, characterized in that, From the inside to the outside, it sequentially includes a conductor, a shielding layer, an insulating layer, a sheath layer, and a hydrophobic anti-icing protective layer. The insulating cable material is extruded outside the shielding layer to obtain the insulating layer. The insulating cable material includes 30-40 parts by weight of MAH-grafted polypropylene resin, 23-34 parts by weight of ethylene-propylene copolymer, 15-20 parts by weight of hydrogenated styrene-butadiene-styrene block copolymer, 2-3 parts by weight of compatibilizer, and 5-8 parts by weight of doubly modified hexagonal boron nitride; The hydrophobic anti-icing coating is sprayed outside the sheath layer to form a hydrophobic anti-icing protective layer. The hydrophobic anti-icing coating includes 53-68 parts by weight of a semi-solid centrifuge containing ethanol, 28-29 parts by weight of ethanol, 1-1.2 parts by weight of ultraviolet absorber, and 0.8-1 part by weight of antioxidant; The semi-solid centrifuge containing ethanol is obtained by adding MOFs@hydrophobic hybrid particle nanoparticles to a mixed solution of ethanol, deionized water, and 28wt% ammonia water, and then adding perfluorodecyltriethoxysilane and tetraethyl orthosilicate, stirring, and centrifuging; The hydrophobic hybrid particles are prepared by wrapping lignin-calcium carbonate composite powder with chitosan.

2. The preparation process of the environment-friendly polypropylene insulated power cable according to claim 1, characterized in that, It includes the following steps: S1: Preparation of hydrophobic hybrid particles S2: Preparation of hydrophobic anti-icing coating Mix cupric nitrate, 2,3,6,7,10,11-hexahydroxy triphenylene hydrate, and N,N-dimethylformamide aqueous solution, then add hydrophobic hybrid particles to prepare MOFs@hydrophobic hybrid particle nanoparticles. Then add the MOFs@hydrophobic hybrid particle nanoparticles to the mixed solution, and then add perfluorodecyltriethoxysilane and tetraethyl orthosilicate to react, and then mix and react with silicon-modified polyester, dimethyl carbonate, and ethanol to prepare a hydrophobic anti-icing coating; S3: Double modification of hexagonal boron nitride Etch and modify hexagonal boron nitride with thionyl chloride, and then modify it with succinic acid to prepare doubly modified hexagonal boron nitride; S4: Preparation of insulating cable material S5: Preparation of power cable Wrap the shielding layer on the surface of the conductor material, and then wrap the insulating layer to obtain a core. Wrap the sheath layer on the surface of the core, and spray the hydrophobic anti-icing coating on the surface of the sheath layer to obtain a power cable.

3. The preparation process of an environment-friendly polypropylene insulated power cable according to claim 2, characterized in that, Step S1, the preparation of hydrophobic hybrid particles, specifically includes the following steps: S1.1: Add 1.23-1.32 parts by weight of lignin to 60-80 parts by weight of tetrahydrofuran to obtain a lignin-tetrahydrofuran mixed solution. Add 0.9-1.2 parts by weight of chitosan to 90-100 parts by weight of 0.1M acetic acid to obtain a chitosan solution; S1.2: Add 0.6-0.8 parts by weight of calcium carbonate to 20-30 parts by weight of deionized water, then drop the calcium carbonate suspension into the lignin-tetrahydrofuran mixed solution, and then stir in a fume hood until the tetrahydrofuran completely volatilizes, and then perform freeze-drying to obtain lignin-calcium carbonate composite powder; S1.3: Add 2 - 3 parts by weight of lignin - calcium carbonate composite powder to 8 - 10 parts by weight of deionized water to obtain a lignin - calcium carbonate suspension. Then add the lignin - calcium carbonate suspension to the chitosan solution, and then adjust the pH to neutral. Stir and react for 2 - 3 h, and then freeze - dry to obtain hydrophobic hybrid microparticles.

4. The preparation process of an environmentally friendly polypropylene insulated power cable according to claim 2, characterized in that, Step S2 Preparation of the hydrophobic anti - icing coating, which specifically includes the following steps: S2.1: Add 9.7 - 10.2 parts by weight of copper nitrate and 6.5 - 8 parts by weight of 2,3,6,7,10,11 - hexahydroxytriphenylene hydrate to a mixed solution of 1000 - 1200 parts by weight of N,N - dimethylformamide and deionized water. N,N - dimethylformamide and deionized water are mixed in a volume ratio of 1:9 - 10. Add 25 - 38 parts by weight of hydrophobic hybrid microparticles, and then stir and react at 85 - 90 °C. Then filter and dry to obtain MOFs@hydrophobic hybrid microparticle nanoparticles; S2.2: Mix ethanol, deionized water and 28 wt% ammonia water in a volume ratio of (75 - 78):(23 - 25):(2 - 3) to obtain a mixed solution. Add 10 - 12 parts by weight of MOFs@hydrophobic hybrid microparticle nanoparticles to 500 - 520 parts by weight of the mixed solution, stir and then perform ultrasonic treatment. Then add 8 - 10 parts by weight of perfluorodecyltriethoxysilane and 1 - 2 parts by weight of tetraethyl orthosilicate, and stir at room temperature for 2 - 3 h. Then centrifuge to obtain a semi - solid centrifuge body containing ethanol; S2.3: Add 2 - 3 parts by weight of silicon - modified polyester to 100 - 120 parts by weight of dimethyl carbonate, then add 53 - 68 parts by weight of the semi - solid centrifuge body containing ethanol, stir and react for 1 - 2 h. Then add 28 - 29 parts by weight of ethanol, stir, and finally add 1 - 1.2 parts by weight of ultraviolet absorber and 0.8 - 1 part by weight of antioxidant, and stir and mix to obtain a hydrophobic anti - icing coating.

5. The preparation process of an environment-friendly polypropylene insulated power cable according to claim 2, characterized in that, Step S3 Double modification of hexagonal boron nitride, which specifically includes the following steps: S3.1: Add 15 - 18 parts by weight of chloroform and 30 - 35 parts by weight of thionyl chloride to 5 - 8 parts by weight of hexagonal boron nitride. Stir and then perform ultrasonic treatment, and finally stir and react at room temperature for 48 - 50 h. Then centrifuge, wash and dry to obtain etched - modified hexagonal boron nitride; S3.2: Add 3 - 5 parts by weight of etched - modified hexagonal boron nitride and 1.2 - 1.8 parts by weight of succinic acid to 50 - 60 parts by weight of toluene, ultrasonically disperse, and then place it in a flask equipped with a stirrer and a condenser. React at 110 - 120 °C for 8 - 10 h, then filter, and then wash, filter by suction and dry to obtain double - modified hexagonal boron nitride.

6. The preparation process of an environment-friendly polypropylene insulated power cable according to claim 2, characterized in that, Step S4 Preparation of the insulating cable material, which specifically includes the following steps: Mix the MAH - grafted modified polypropylene resin, ethylene - propylene copolymer, hydrogenated styrene - butadiene - styrene block copolymer, compatibilizer and double - modified hexagonal boron nitride, and then perform ultrasonic oscillation for 20 - 30 min to obtain the insulating cable material.

7. The preparation process of an environment-friendly polypropylene insulated power cable according to claim 2, characterized in that, Step S5 Preparation of the power cable, which specifically includes the following steps: S5.1: After covering the shielding layer outside the conductor to form the shielding layer, the insulating cable material is melt-extruded so that it wraps around the surface of the shielding layer material to obtain a core wire; S5.2: A polyvinyl chloride is extruded on the surface of the core wire to form a sheath layer, and a hydrophobic anti-icing coating is sprayed on the sheath layer. After curing, a power cable is obtained.

8. The preparation process of an environmentally friendly polypropylene insulated power cable according to claim 6, characterized in that, In step S4, the compatibilizer is a PE-g-GMA compatibilizer.

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