An environment-friendly polypropylene insulated power cable and its manufacturing process

Abstract

The present invention provides an environmentally friendly polypropylene insulated power cable and its preparation process, belonging to the field of cable preparation technology. The preparation process comprises the following steps: preparation of hydrophobic hybrid particles; preparation of a hydrophobic anti-icing coating; dual modification of hexagonal boron nitride; preparation of insulating cable materials; and preparation of a power cable. The cable prepared by the present invention has good insulation performance, can increase tensile strength and extend the service life of the cable. After spraying the hydrophobic anti-icing coating, it has a significant super-hydrophobic effect and can extend the service life of the cable in low temperature and high relative humidity environments, preventing icing and ensuring the safety of the cable.

Description

Technical Field

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

[0002] With the global energy structure adjustment and the rapid growth of power transmission demand, the performance and environmental friendliness of power cables, as the core carrier of power transmission, have attracted widespread attention. Traditional power cable insulation materials mostly use polyvinyl chloride (PVC) or cross-linked polyethylene (XLPE), but these materials have significant drawbacks: PVC releases large amounts of toxic halogen gases when burned, and the production process of XLPE relies on a chemical cross-linking process, which has problems such as high energy consumption and difficult degradation of cross-linking byproducts. In recent years, polypropylene (PP) has been regarded as an ideal environmentally friendly alternative insulation material due to its excellent high-temperature resistance, mechanical strength, and recyclability.

[0003] Although polypropylene has many advantages as an insulating material, there are still some technical difficulties that need to be solved in the process of applying it to power cables: When polypropylene is used as a cable insulation material, it has the disadvantage of insufficient flexibility and cannot meet the requirements of cable laying, installation and production, resulting in it being unable to be used directly and must be toughened and modified. Currently, the most common way to modify polypropylene is to use thermoplastic elastomers and polypropylene for physical modification through melt blending. When the blended toughened polypropylene cable insulation material generates heat during long-term operation, it is difficult to effectively dissipate the heat. 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 is running outdoors, especially in low temperature and high relative humidity environments such as in the north, ice and condensation are prone to appear on the surface, which will not only increase the weight of the cable, but may also damage the insulation and mechanical properties of the cable. Most of the existing technologies solve the problems of icing and condensation by forming a super-hydrophobic coating on the cable surface. However, the super-hydrophobic coatings reported in most literatures have poor overall performance and poor bonding between the coating and the cable. Therefore, a binder is added. The introduction of the binder usually embeds low-surface-energy nanoparticles, thereby significantly increasing the surface energy of the coating and reducing hydrophobicity.

[0004] Therefore, in view of the problems existing in the above-mentioned prior art, there is an urgent need to develop an environmentally friendly polypropylene insulated power cable and its preparation process that can effectively improve the insulation reliability, thermal conductivity and super-hydrophobic anti-icing performance of the polypropylene insulated cable. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the present invention aims to provide an environmentally friendly polypropylene insulated power cable and a preparation process thereof.

[0006] An environmentally friendly polypropylene insulated power cable comprises, from the inside out, a conductor, a shielding layer, an insulating layer, a sheath layer, and a hydrophobic anti-icing protective layer. An insulating cable material is extruded over the shielding layer to form the insulating layer. The insulating cable material comprises 30-40 parts by weight of MAH graft-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 a compatibilizer, and 5-8 parts by weight of double-modified hexagonal boron nitride.

[0007] A hydrophobic anti-icing coating is sprayed on the outside of the jacket layer to form a hydrophobic anti-icing protective layer, wherein the hydrophobic anti-icing coating comprises 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 an ultraviolet absorber, and 0.8-1 parts by weight of an antioxidant;

[0008] The semi-solid centrifugal body containing ethanol is obtained by adding MOFs@hydrophobic hybrid microparticles to a mixed solution of ethanol, deionized water and 28 wt% ammonia water, and then adding perfluorodecyltriethoxysilane and ethyl orthosilicate, stirring and centrifuging.

[0009] The hydrophobic hybrid particles are prepared by wrapping lignin-calcium carbonate composite powder with chitosan.

[0010] A preparation process of an environmentally friendly polypropylene insulated power cable comprises the following steps:

[0011] S1: Preparation of hydrophobic hybrid microparticles

[0012] S2: Preparation of hydrophobic anti-icing coating

[0013] Copper nitrate, 2,3,6,7,10,11-hexahydroxytriphenylene hydrate and an N,N-dimethylformamide aqueous solution were mixed, and then hydrophobic hybrid microparticles were added to prepare MOFs@hydrophobic hybrid microparticle nanoparticles. The MOFs@hydrophobic hybrid microparticle nanoparticles were then added to the mixed solution, and then perfluorodecyltriethoxysilane and ethyl orthosilicate were added to react, and then mixed with silicon-modified polyester, dimethyl carbonate and ethanol to prepare a hydrophobic anti-icing coating.

[0014] S3: Double modification of hexagonal boron nitride

[0015] Hexagonal boron nitride was modified by etching with thionyl chloride and then modified with succinic acid to prepare double-modified hexagonal boron nitride.

[0016] S4: Preparation of insulating cable materials

[0017] S5: Preparation of power cables

[0018] A shielding layer is wrapped on the surface of the conductor material, and then an insulating layer is wrapped to obtain a wire core, a sheath layer is wrapped on the surface of the wire core, and a hydrophobic anti-icing coating is sprayed on the surface of the sheath layer to obtain a power cable.

[0019] Furthermore, step S1 of preparing the hydrophobic hybrid microparticles specifically includes the following steps:

[0020] 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 rpm for 20-30 minutes to obtain a lignin-tetrahydrofuran mixture. Add 0.9-1.2 parts by weight of chitosan to 90-100 parts by weight of 0.1 M acetic acid, and stir and mix for 2-3 hours to obtain a chitosan solution.

[0021] S1.2: Add 0.6-0.8 parts by weight of calcium carbonate to 20-30 parts by weight of deionized water and disperse for 10-20 minutes. Then, add the calcium carbonate suspension dropwise to the lignin-tetrahydrofuran mixture at a rate of 20-30 mL / min. Then, stir in a fume hood until the tetrahydrofuran is completely evaporated, and then freeze-dry to obtain a lignin-calcium carbonate composite powder;

[0022] 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, then adjust the pH to neutral, stir the reaction for 2-3 hours, and then freeze-dry to obtain hydrophobic hybrid microparticles.

[0023] Furthermore, step S2 of preparing the hydrophobic anti-icing coating specifically includes the following steps:

[0024] S2.1: adding 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 in a volume ratio of 1:9-10, followed by stirring for 10-20 minutes, adding 25-38 parts by weight of hydrophobic hybrid microparticles, and stirring the mixture at 85-90° C. and 500-600 rpm for 15-18 hours, filtering, and drying to obtain MOFs@hydrophobic hybrid microparticle nanoparticles;

[0025] S2.2: Ethanol, deionized water, and 28 wt% ammonia water are mixed in a volume ratio of (75-78):(23-25):(2-3) to obtain a mixed solution, 10-12 parts by weight of MOFs@hydrophobic hybrid microparticles are added to 500-520 parts by weight of the mixed solution, and the mixture is stirred for 10-12 minutes, followed by ultrasonic treatment for 5-8 minutes. 8-10 parts by weight of perfluorodecyltriethoxysilane and 1-2 parts by weight of ethyl orthosilicate are then added, and the mixture is stirred at room temperature for 2-3 hours, followed by centrifugation to obtain a semi-solid centrifuge containing ethanol;

[0026] 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 a semi-solid centrifuge containing ethanol, stir and react for 1-2 hours, then add 28-29 parts by weight of ethanol, then stir at 3000-5000 r / min for 3-4 hours, finally add 1-1.2 parts by weight of ultraviolet absorber UV-1130 and 0.8-1 parts by weight of antioxidant 1010, stir and mix for 1-2 hours to obtain a hydrophobic anti-icing coating.

[0027] Furthermore, step S3 of double modification of hexagonal boron nitride specifically includes the following steps:

[0028] 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 rpm for 30-40 minutes, then ultrasonicate for 10-12 minutes, and finally stir and react at 500-800 rpm at room temperature for 48-50 hours, then centrifuge, wash, and dry to obtain etched hexagonal boron nitride;

[0029] S3.2: Add 3-5 parts by weight of etching-modified hexagonal boron nitride and 1.2-1.8 parts by weight of succinic acid to 50-60 parts by weight of toluene, and disperse them ultrasonically at 50-80W for 20-30 minutes. Then, place them in a flask with a stirring and condensing device, and react at 110-120°C for 8-10 hours. Then, filter, wash and filter with anhydrous ethanol 2-3 times, and dry to obtain doubly modified hexagonal boron nitride.

[0030] Furthermore, step S4 of preparing the insulating cable material specifically includes the following steps:

[0031] S4.1: Add 40-50 parts by weight of polypropylene resin to a torsional rheometer at 180-185°C, then mix at 60-80 rpm for 3-5 minutes. Then, add 1-2% by weight of a styrene derivative and mix for 3-5 minutes. Then, add 3-5% by weight of MAH and mix for 3-5 minutes. Finally, add 0.025-0.028% by weight of dicumyl peroxide and mix for 10-12 minutes to obtain a MAH-grafted modified polypropylene resin.

[0032] 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 doubly modified hexagonal boron nitride, and then ultrasonically vibrate for 20-30 minutes to obtain an insulating cable material.

[0033] Furthermore, step S5 of preparing the power cable specifically includes the following steps:

[0034] S5.1: After the shielding layer is wrapped around the conductor to form a shielding layer, the insulating cable material is melt-extruded at 160-180°C and 15-20 MPa to wrap the insulating cable material around the surface of the shielding layer to obtain a wire core;

[0035] S5.2: Extrude polyvinyl chloride on the surface of the wire core to form a sheath layer, spray hydrophobic anti-icing paint on the sheath layer with a spray distance of 200-300mm and a film thickness of 20-30μm. Curing at room temperature for 24-28h to obtain a power cable.

[0036] Furthermore, in step S4.2, the compatibilizer is PE-g-GMA compatibilizer.

[0037] Compared with the prior art, the present invention has at least the following beneficial effects:

[0038] 1. The present invention introduces more amino groups and hydroxyl groups on the surface of hexagonal boron nitride through dichloride treatment, increases surface active groups, reduces the van der Waals force between nanosheets, inhibits agglomeration, and improves its dispersion in the matrix. It is then modified with succinic acid to make its surface rougher, which allows for stronger interfacial interaction with the substrate. Under the action of external force, it can more effectively transfer loads, reduce debonding or cracking between the filler and the matrix, thereby increasing tensile strength and extending the service life of the cable. The addition of double-modified hexagonal boron nitride can effectively inhibit the accumulation of space charge, significantly improve DC breakdown strength, reduce the risk of electrical breakdown, and improve insulation reliability. In addition, hexagonal boron nitride itself has high thermal conductivity. After modification, it is evenly dispersed in the polypropylene matrix to form an efficient heat conduction network, accelerate the dissipation of heat during cable operation, and reduce the aging effect of long-term high temperature on the insulation layer.

[0039] 2. The present invention aggregates lignin molecules through the interaction of π-π and hydrogen bonds between lignin molecules, precipitates and tightly coats the surface of calcium carbonate particles, and then introduces chitosan. Since lignin is negatively charged and chitosan is positively charged, chitosan can be attached to the surface of lignin-calcium carbonate composite powder through electrostatic interaction, thereby improving stability and improving its rough structure, significantly improving 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. Perfluorodecyl triethoxysilane and ethyl orthosilicate are then used for modification to further improve the superhydrophobic effect. The metal organic framework compound can effectively absorb light and convert it into heat, and the coating has many photothermal traps, which 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, so that the coating has photothermal conversion performance and superhydrophobic effect, which can extend the service life of the cable in a low temperature and high relative humidity environment, avoid icing, and ensure the safety of cable use.

[0040] 3. The present invention adds a silicon-modified polyester binder to the coating preparation. The silicon-modified polyester binder can enhance the bonding strength between the coating and the substrate and the bonding strength between the semi-solid centrifugal bodies in the coating, thereby improving the mechanical stability and strength of the coating, and then improving the mechanical strength of the cable. In addition, the addition of the silicon-modified polyester binder and the adjustment of the ethanol content can achieve phase separation, allowing the semi-solid centrifugal bodies to be wrapped around the silicon-modified polyester binder particles, thereby not affecting the hydrophobic properties. After the coating is cured, under the adhesion of the silicon-modified polyester, microaggregates composed of the silicon-modified polyester binder particles and the semi-solid centrifugal bodies 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

[0041] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, further serve to explain the principles of the invention and to enable one skilled in the art to make and use the invention.

[0042] Figure 1 is a SEM image of the hydrophobic hybrid particles of an embodiment of the present invention;

[0043] Figure 2 This is an SEM image of the double-modified hexagonal boron nitride according to an embodiment of the present invention;

[0044] Figure 3 This is the SEM image of unmodified hexagonal boron nitride. DETAILED DESCRIPTION

[0045] The following describes in detail the preparation process of an environmentally friendly polypropylene insulated power cable provided by the present invention, with reference to the accompanying drawings and specific examples. It is also noted that, for the sake of completeness, the following examples are optimal and preferred embodiments, and those skilled in the art may employ alternative methods for implementing certain known techniques. Furthermore, the accompanying drawings are intended only to provide a more detailed description of the embodiments and are not intended to limit the present invention.

[0046] In the following examples and comparative examples:

[0047] The conductors are composed 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 of equal diameter, and the outer core layer is composed of twelve aluminum alloy wires of equal diameter.

[0048] Example 1

[0049] A preparation process of an environmentally friendly polypropylene insulated power cable comprises the following steps:

[0050] S1: Preparation of hydrophobic hybrid microparticles

[0051] S1.1: Add 1.23 parts by weight of lignin to 60 parts by weight of tetrahydrofuran, and stir at 600 rpm for 20 minutes 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 for 2 hours to obtain a chitosan solution.

[0052] S1.2: Add 0.6 parts by weight of calcium carbonate to 20 parts by weight of deionized water and disperse for 10 minutes. Then, add the calcium carbonate suspension dropwise to the lignin-tetrahydrofuran mixture at a rate of 20 mL / min. Then, stir in a fume hood until the tetrahydrofuran is completely evaporated, and then freeze-dry to obtain a lignin-calcium carbonate composite powder.

[0053] 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, adjust the pH to neutral, stir the reaction for 2 hours, and then freeze-dry to obtain hydrophobic hybrid microparticles;

[0054] S2: Preparation of hydrophobic anti-icing coating

[0055] S2.1: 9.7 parts by weight of copper nitrate and 6.5 parts by weight of 2,3,6,7,10,11-hexahydroxytriphenylene hydrate were added to a mixed solution of 1000 parts by weight of N,N-dimethylformamide and deionized water in a volume ratio of 1:9, followed by stirring for 10 minutes. 25 parts by weight of hydrophobic hybrid microparticles were added, and the mixture was stirred at 85°C and 500 rpm for 15 hours. The mixture was then filtered and dried to obtain MOFs@hydrophobic hybrid microparticle nanoparticles.

[0056] S2.2: Ethanol, deionized water, and 28 wt% ammonia water were mixed in a volume ratio of 75:23:2 to obtain a mixed solution. 10 parts by weight of MOFs@hydrophobic hybrid microparticles were added to 500 parts by weight of the mixed solution, and the mixture was stirred for 10 minutes, followed by ultrasonic treatment for 5 minutes. 8 parts by weight of perfluorodecyltriethoxysilane and 1 part by weight of ethyl orthosilicate were then added, and the mixture was stirred at room temperature for 2 hours. The mixture was then centrifuged to obtain a semi-solid centrifuge containing ethanol.

[0057] 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 a semi-solid centrifuge containing ethanol, stir and react for 1 hour, then add 28 parts by weight of ethanol, then stir at 3000 rpm for 3 hours, 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 hour to obtain a hydrophobic anti-icing coating;

[0058] S3: Double modification of hexagonal boron nitride

[0059] S3.1: To 5 parts by weight of hexagonal boron nitride, 15 parts by weight of chloroform and 30 parts by weight of thionyl chloride were added, and the mixture was stirred at 200 rpm for 30 minutes, followed by ultrasonic treatment for 10 minutes. Finally, the mixture was stirred at 500 rpm at room temperature for 48 hours, and then centrifuged, washed, and dried to obtain etched hexagonal boron nitride;

[0060] S3.2: 3 parts by weight of the etched hexagonal boron nitride and 1.2 parts by weight of succinic acid were added to 50 parts by weight of toluene, and ultrasonically dispersed at 50W for 20 minutes. The mixture was then placed in a flask equipped with a stirring and condensing device and reacted at 110°C for 8 hours. The mixture was then filtered, washed with anhydrous ethanol and filtered twice, and dried to obtain the doubly modified hexagonal boron nitride.

[0061] S4: Preparation of insulating cable materials

[0062] S4.1: 40 parts by weight of polypropylene resin was added to a torsional rheometer at 180°C and mixed at 60 rpm for 3 minutes. A styrene derivative (1% by weight) was then added and mixed for 3 minutes. MAH (3% by weight) was then added and mixed for 3 minutes. Finally, 0.025% by weight of dicumyl peroxide was added and mixed for 10 minutes to obtain a MAH-grafted modified polypropylene resin.

[0063] S4.2: 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 were mixed and ultrasonically vibrated for 20 minutes to obtain an insulating cable material;

[0064] S5: Preparation of power cables

[0065] S5.1: After wrapping the copper tape braided shield layer over the conductor to form a shield layer, melt-extrude the insulating cable material at 160°C and 15 MPa to wrap it around the shield layer to form a wire core;

[0066] S5.2: Extrude polyvinyl chloride on the surface of the wire core to form a sheath layer, spray hydrophobic anti-icing paint on the sheath layer with a spray distance of 200 mm and a film thickness of 20 μm. Curing at room temperature for 24 hours to obtain a power cable.

[0067] Example 2

[0068] A preparation process of an environmentally friendly polypropylene insulated power cable comprises the following steps:

[0069] S1: Preparation of hydrophobic hybrid microparticles

[0070] S1.1: Add 1.32 parts by weight of lignin to 80 parts by weight of tetrahydrofuran, and stir at 600 rpm for 20 minutes to obtain a lignin-tetrahydrofuran mixture. Add 1.2 parts by weight of chitosan to 100 parts by weight of 0.1 M acetic acid, and stir for 2 hours to obtain a chitosan solution.

[0071] S1.2: Add 0.8 parts by weight of calcium carbonate to 30 parts by weight of deionized water and disperse for 10 minutes. Then, add the calcium carbonate suspension dropwise to the lignin-tetrahydrofuran mixture at a rate of 20 mL / min. Then, stir in a fume hood until the tetrahydrofuran is completely evaporated, and then freeze-dry to obtain a lignin-calcium carbonate composite powder.

[0072] S1.3: 3 parts by weight of lignin-calcium carbonate composite powder was added to 10 parts by weight of deionized water to obtain a lignin-calcium carbonate suspension. The lignin-calcium carbonate suspension was then added to the chitosan solution. The pH was adjusted to neutral, the mixture was stirred for 2 hours, and then freeze-dried to obtain hydrophobic hybrid microparticles.

[0073] S2: Preparation of hydrophobic anti-icing coating

[0074] S2.1: 10.2 parts by weight of copper nitrate and 8 parts by weight of 2,3,6,7,10,11-hexahydroxytriphenylene hydrate were added to a mixed solution of 1200 parts by weight of N,N-dimethylformamide and deionized water in a volume ratio of 1:10, followed by stirring for 10 minutes. 38 parts by weight of hydrophobic hybrid microparticles were added, and the mixture was stirred at 85°C and 500 rpm for 15 hours. The mixture was then filtered and dried to obtain MOFs@hydrophobic hybrid microparticle nanoparticles.

[0075] S2.2: Ethanol, deionized water, and 28 wt% ammonia water were mixed in a volume ratio of 78:25:3 to obtain a mixed solution. 12 parts by weight of MOFs@hydrophobic hybrid microparticles were added to 520 parts by weight of the mixed solution, and the mixture was stirred for 10 minutes, followed by ultrasonic treatment for 5 minutes. Then, 10 parts by weight of perfluorodecyltriethoxysilane and 2 parts by weight of ethyl orthosilicate were added, and the mixture was stirred at room temperature for 2 hours. The mixture was then centrifuged to obtain a semi-solid centrifuge containing ethanol.

[0076] S2.3: 3 parts by weight of silicon-modified polyester was added to 120 parts by weight of dimethyl carbonate, followed by the addition of 68 parts by weight of a semi-solid centrifuge containing ethanol, and the mixture was stirred for 1 hour. 29 parts by weight of ethanol was then added, followed by stirring at 3000 rpm for 3 hours. Finally, 1.2 parts by weight of UV absorber UV-1130 and 1 part by weight of antioxidant 1010 were added, and the mixture was stirred for 1 hour to obtain a hydrophobic anti-icing coating.

[0077] S3: Double modification of hexagonal boron nitride

[0078] S3.1: To 8 parts by weight of hexagonal boron nitride, 18 parts by weight of chloroform and 35 parts by weight of thionyl chloride were added, and the mixture was stirred at 200 rpm for 30 minutes, followed by ultrasonic treatment for 10 minutes. Finally, the mixture was stirred at 500 rpm at room temperature for 48 hours, and then centrifuged, washed, and dried to obtain etched hexagonal boron nitride.

[0079] S3.2: 5 parts by weight of the etched hexagonal boron nitride and 1.8 parts by weight of succinic acid were added to 60 parts by weight of toluene, and ultrasonically dispersed at 50W for 20 minutes. The mixture was then placed in a flask equipped with a stirring and condensing device and reacted at 110°C for 8 hours. The mixture was then filtered, washed with anhydrous ethanol and filtered twice, and dried to obtain the double-modified hexagonal boron nitride.

[0080] S4: Preparation of insulating cable materials

[0081] S4.1: Add 50 parts by weight of polypropylene resin to a torsional rheometer at 180°C and mix at 60 rpm for 3 minutes. Then, add 2% by weight of a styrene derivative and mix for 3 minutes. Then, add 5% by weight of MAH and mix for 3 minutes. Finally, add 0.028% by weight of dicumyl peroxide and mix for 10 minutes to obtain a MAH-grafted modified polypropylene resin.

[0082] S4.2: 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 were mixed and ultrasonically vibrated for 20 minutes to obtain an insulating cable material;

[0083] S5: Preparation of power cables

[0084] S5.1: After wrapping the copper tape braided shield layer over the conductor to form a shield layer, melt-extrude the insulating cable material at 160°C and 15 MPa to wrap it around the shield layer to form a wire core;

[0085] S5.2: Extrude polyvinyl chloride on the surface of the wire core to form a sheath layer, spray hydrophobic anti-icing paint on the sheath layer with a spray distance of 200 mm and a film thickness of 20 μm. Curing at room temperature for 24 hours to obtain a power cable.

[0086] Example 3

[0087] A preparation process of an environmentally friendly polypropylene insulated power cable comprises the following steps:

[0088] S1: Preparation of hydrophobic hybrid microparticles

[0089] S1.1: Add 1.23 parts by weight of lignin to 60 parts by weight of tetrahydrofuran, and stir at 700 rpm for 30 minutes 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 for 3 hours to obtain a chitosan solution.

[0090] S1.2: Add 0.6 parts by weight of calcium carbonate to 20 parts by weight of deionized water and disperse for 20 minutes. Then, add the calcium carbonate suspension dropwise to the lignin-tetrahydrofuran mixture at a rate of 30 mL / min. Then, stir in a fume hood until the tetrahydrofuran is completely evaporated, and then freeze-dry to obtain a lignin-calcium carbonate composite powder.

[0091] 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, adjust the pH to neutral, stir the reaction for 3 hours, and then freeze-dry to obtain hydrophobic hybrid microparticles;

[0092] S2: Preparation of hydrophobic anti-icing coating

[0093] S2.1: 9.7 parts by weight of copper nitrate and 6.5 parts by weight of 2,3,6,7,10,11-hexahydroxytriphenylene hydrate were added to a mixed solution of 1000 parts by weight of N,N-dimethylformamide and deionized water in a volume ratio of 1:9, followed by stirring for 20 minutes. 25 parts by weight of hydrophobic hybrid microparticles were added, and the mixture was stirred at 90°C and 600 rpm for 18 hours. The mixture was then filtered and dried to obtain MOFs@hydrophobic hybrid microparticle nanoparticles.

[0094] S2.2: Ethanol, deionized water, and 28 wt% ammonia water were mixed in a volume ratio of 75:23:2 to obtain a mixed solution. 10 parts by weight of MOFs@hydrophobic hybrid microparticles were added to 500 parts by weight of the mixed solution, and the mixture was stirred for 12 minutes, followed by ultrasonic treatment for 8 minutes. 8 parts by weight of perfluorodecyltriethoxysilane and 1 part by weight of ethyl orthosilicate were then added, and the mixture was stirred at room temperature for 3 hours. The mixture was then centrifuged to obtain a semi-solid centrifuge containing ethanol.

[0095] 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 a semi-solid centrifuge containing ethanol, and stir for 2 hours. Then, add 28 parts by weight of ethanol, and stir at 5000 rpm for 4 hours. Finally, add 1 part by weight of UV absorber UV-1130 and 0.8 part by weight of antioxidant 1010, and stir and mix for 2 hours to obtain a hydrophobic anti-icing coating.

[0096] S3: Double modification of hexagonal boron nitride

[0097] S3.1: To 5 parts by weight of hexagonal boron nitride, 15 parts by weight of chloroform and 30 parts by weight of thionyl chloride were added, and the mixture was stirred at 300 rpm for 40 minutes, followed by ultrasonic treatment for 12 minutes. Finally, the mixture was stirred at 800 rpm at room temperature for 50 hours, and then centrifuged, washed, and dried to obtain etched hexagonal boron nitride.

[0098] S3.2: 3 parts by weight of the etched hexagonal boron nitride and 1.2 parts by weight of succinic acid were added to 50 parts by weight of toluene, and ultrasonically dispersed at 80W for 30 minutes. The mixture was then placed in a flask equipped with a stirring and condensing device and reacted at 120°C for 10 hours. The mixture was then filtered, washed with anhydrous ethanol and filtered three times, and dried to obtain the doubly modified hexagonal boron nitride.

[0099] S4: Preparation of insulating cable materials

[0100] S4.1: 40 parts by weight of polypropylene resin was added to a torsional rheometer at 185°C and mixed at 80 rpm for 5 minutes. A styrene derivative (1% by weight) was then added and mixed for 5 minutes. MAH (3% by weight) was then added and mixed for 5 minutes. Finally, 0.025% by weight of dicumyl peroxide was added and mixed for 12 minutes to obtain a MAH-grafted modified polypropylene resin.

[0101] S4.2: 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 were mixed and ultrasonically vibrated for 30 minutes to obtain an insulating cable material;

[0102] S5: Preparation of power cables

[0103] S5.1: After wrapping the copper tape braided shield layer over the conductor to form a shield layer, melt-extrude the insulating cable material at 180°C and 20 MPa to wrap it around the shield layer to form a wire core;

[0104] S5.2: Extrude polyvinyl chloride on the surface of the wire core to form a sheath layer, spray hydrophobic anti-icing paint on the sheath layer with a spray distance of 300 mm and a film thickness of 30 μm. Curing at room temperature for 28 hours to obtain a power cable.

[0105] Comparative Example 1

[0106] Compared with Example 1, the difference of Comparative Example 1 is that Comparative Example 1 removes step S3.2, replaces the double-modified hexagonal boron nitride in step S4.2 with etching-modified hexagonal boron nitride, and prepares the power cable without changing the other steps, which is recorded as Comparative Example 1.

[0107] Comparative Example 2

[0108] Compared with Example 1, the difference of Comparative Example 2 is that step S3 is removed in Comparative Example 2, and the double-modified hexagonal boron nitride in step S4.2 is replaced with hexagonal boron nitride. The remaining steps remain unchanged to prepare the power cable, which is recorded as Comparative Example 2.

[0109] Comparative Example 3

[0110] Compared with Example 1, the difference of Comparative Example 3 is that Comparative Example 3 removes steps S1-S2 and step S5.2 of "spraying hydrophobic anti-icing coating on the sheath layer, spraying distance 200mm, controlling film thickness to 20μm, and curing at room temperature for 24h". In step S5.2, polyvinyl chloride is extruded on the surface of the core to form a sheath layer, and a power cable can be prepared, which is recorded as Comparative Example 3.

[0111] Comparative Example 4

[0112] Compared with Example 1, the difference of Comparative Example 4 is that Comparative Example 4 removes step S2.3 and replaces step S2.2 with "mixing ethanol, deionized water and 28 wt% ammonia water in a volume ratio of 75:23:2 to obtain a mixed solution, adding 10 parts by weight of MOFs@hydrophobic hybrid microparticles to 500 parts by weight of the mixed solution, stirring for 10 minutes, and then ultrasonically treating for 5 minutes, and then adding 8 parts by weight of perfluorodecyltriethoxysilane and 1 part by weight of ethyl orthosilicate, stirring at room temperature for 2 hours, and then adding 1 part by weight of ultraviolet absorber UV-1130 and 0.8 parts by weight of antioxidant 1010, stirring and mixing for 1 hour to obtain a hydrophobic anti-icing coating", and the remaining steps remain unchanged to prepare a power cable, which is recorded as Comparative Example 4.

[0113] The performance tests were performed on the cables prepared in Examples 1-3 and Comparative Examples 1-2. The test results are shown in Table 1.

[0114] Table 1. Cable performance test results of Examples 1-3 and Comparative Examples 1-2

[0115]

[0116] From the data in Table 1, it can be seen that the addition of double-modified hexagonal boron nitride can improve the tensile strength and elongation at break, and can also improve the DC breakdown strength and thermal conductivity, thereby reducing the aging effect of long-term high temperature on the insulation layer.

[0117] The performance tests were performed on the cables prepared in Examples 1-3 and Comparative Examples 3-4. The test results are shown in Table 2.

[0118] Table 2. Hydrophobicity test results of cables in Examples 1-3 and Comparative Examples 3-4

[0119]

[0120] It can be seen from the data in Table 2 that spraying the hydrophobic anti-icing coating on the sheath layer of the present invention can significantly improve the hydrophobicity of the cable, and adding a silicon-modified polyester binder in the preparation of the hydrophobic anti-icing coating does not affect the hydrophobic effect of the coating.

[0121] The cables prepared in Examples 1-3 and Comparative Example 3 were placed in a -15°C, 80% RH environment. A xenon lamp was placed directly above the sample, and then the xenon lamp was adjusted to provide stable simulated light (0.1 sun). The surface temperature of the sample was recorded after 15 minutes. The measurement was performed three times and the average value was taken. The results are shown in Table 3.

[0122] Table 3. Surface temperature measurement results of Examples 1-3 and Comparative Example 3

[0123]

[0124] It can be seen from the data in Table 3 that the hydrophobic anti-icing coating prepared by the present invention can exhibit good light-to-heat conversion performance, can prevent the cable from freezing in a low temperature and high humidity environment, and can increase the service life of the cable in a cold environment.

[0125] The performance tests were performed on the cables prepared in Examples 1-3 and Comparative Example 4. The test results are shown in Table 4.

[0126] Wear resistance test: The hydrophobicity was tested again after rubbing 3000 times according to the Taber abrasion test (125 g load, CS-10 grinding wheel, ASTM D4060).

[0127] Table 4. Performance test results of Examples 1-3 and Comparative 4

[0128]

[0129] From the data in Table 4, it can be seen that the addition of silicon-modified polyester binder can improve the tensile strength of the cable, and the cable still has super-hydrophobic properties after the friction test, indicating that the addition of silicon-modified polyester binder can improve the wear resistance of the coating without affecting the hydrophobic effect.

[0130] from Figure 1 It can be seen that the hydrophobic hybrid microparticles have a rough structure. Figure 2 and Figure 3 It can be seen that the surface of the double-modified hexagonal boron nitride is rougher than that of the unmodified one.

[0131] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. An environmentally friendly polypropylene insulated power cable, characterized in that: The invention discloses a cable comprising a conductor, a shielding layer, an insulating layer, a sheath layer and a hydrophobic anti-icing protective layer in order from the inside to the outside. The insulating cable material is extruded outside the shielding layer to obtain an insulating layer. The insulating cable material comprises 30-40 parts by weight of MAH graft-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 a compatibilizer and 5-8 parts by weight of double-modified hexagonal boron nitride. A hydrophobic anti-icing coating is sprayed on the outside of the jacket layer to form a hydrophobic anti-icing protective layer, wherein the hydrophobic anti-icing coating comprises 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 an ultraviolet absorber, and 0.8-1 parts by weight of an antioxidant; The semi-solid centrifugal body containing ethanol is obtained by adding MOFs@hydrophobic hybrid microparticles to a mixed solution of ethanol, deionized water and 28 wt% ammonia water, and then adding perfluorodecyltriethoxysilane and ethyl orthosilicate, stirring and centrifuging. The hydrophobic hybrid particles are prepared by wrapping lignin-calcium carbonate composite powder with chitosan.

2. A process for preparing the environmentally friendly polypropylene insulated power cable according to claim 1, characterized in that: The steps include: S1: Preparation of hydrophobic hybrid microparticles S2: Preparation of hydrophobic anti-icing coating Copper nitrate, 2,3,6,7,10,11-hexahydroxytriphenylene hydrate and an N,N-dimethylformamide aqueous solution were mixed, and then hydrophobic hybrid microparticles were added to prepare MOFs@hydrophobic hybrid microparticle nanoparticles. The MOFs@hydrophobic hybrid microparticle nanoparticles were then added to the mixed solution, and then perfluorodecyltriethoxysilane and ethyl orthosilicate were added to react, and then mixed with silicon-modified polyester, dimethyl carbonate and ethanol to prepare a hydrophobic anti-icing coating. S3: Double modification of hexagonal boron nitride Hexagonal boron nitride was modified by etching with thionyl chloride and then modified with succinic acid to prepare double-modified hexagonal boron nitride. S4: Preparation of insulating cable materials S5: Preparation of power cables A shielding layer is wrapped on the surface of the conductor material, and then an insulating layer is wrapped to obtain a wire core, a sheath layer is wrapped on the surface of the wire core, and a hydrophobic anti-icing coating is sprayed on the surface of the sheath layer to obtain a power cable.

3. The process for preparing an environmentally friendly polypropylene insulated power cable according to claim 2, characterized in that: Step S1: Preparation of hydrophobic hybrid microparticles, specifically comprising 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 mixture, and add 0.9-1.2 parts by weight of chitosan to 90-100 parts by weight of 0.1 M 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 add the calcium carbonate suspension dropwise to the lignin-tetrahydrofuran mixture, then stir in a fume hood until the tetrahydrofuran is completely evaporated, and then freeze-dry to obtain a 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, then adjust the pH to neutral, stir the reaction for 2-3 hours, and then freeze-dry to obtain hydrophobic hybrid microparticles.

4. The process for preparing an environmentally friendly polypropylene insulated power cable according to claim 2, characterized in that: Step S2: Preparation of hydrophobic anti-icing coating, specifically comprising the following steps: S2.1: adding 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, wherein the N,N-dimethylformamide and deionized water are mixed in a volume ratio of 1:9-10, adding 25-38 parts by weight of hydrophobic hybrid microparticles, and stirring the mixture at 85-90° C., filtering, and drying to obtain MOFs@hydrophobic hybrid microparticle nanoparticles; S2.2: Ethanol, deionized water, and 28 wt% ammonia water are mixed in a volume ratio of (75-78):(23-25):(2-3) to obtain a mixed solution, 10-12 parts by weight of MOFs@hydrophobic hybrid microparticles are added to 500-520 parts by weight of the mixed solution, the mixture is stirred and then ultrasonicated, and then 8-10 parts by weight of perfluorodecyltriethoxysilane and 1-2 parts by weight of ethyl orthosilicate are added, the mixture is stirred at room temperature for 2-3 hours, and then centrifuged to obtain a semi-solid centrifuge 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 a semi-solid centrifuge containing ethanol, stir and react for 1-2 hours, then add 28-29 parts by weight of ethanol, stir, and finally add 1-1.2 parts by weight of a UV absorber and 0.8-1 part by weight of an antioxidant, stir and mix to obtain a hydrophobic anti-icing coating.

5. The process for preparing an environmentally friendly polypropylene insulated power cable according to claim 2, characterized in that: Step S3: double modification of hexagonal boron nitride, specifically comprising 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 ultrasonicate. Finally, stir and react at room temperature for 48-50 hours, then centrifuge, wash, and dry to obtain etched hexagonal boron nitride; S3.2: Add 3-5 parts by weight of etching-modified hexagonal boron nitride and 1.2-1.8 parts by weight of succinic acid to 50-60 parts by weight of toluene, disperse them ultrasonically, and then place them in a flask with a stirring and condensing device. React at 110-120°C for 8-10 hours, then filter, wash, filter, and dry to obtain doubly modified hexagonal boron nitride.

6. The process for preparing an environmentally friendly polypropylene insulated power cable according to claim 2, characterized in that: Step S4 is the preparation of insulating cable materials, which specifically includes the following steps: MAH graft modified polypropylene resin, ethylene-propylene copolymer, hydrogenated styrene-butadiene-styrene block copolymer, compatibilizer and double modified hexagonal boron nitride are mixed and ultrasonically shaken for 20-30 minutes to obtain an insulating cable material.

7. The process for preparing an environmentally friendly polypropylene insulated power cable according to claim 2, characterized in that: Step S5: preparing the power cable, specifically comprising the following steps: S5.1: After the shielding layer is wrapped around the conductor to form a shielding layer, the insulating cable material is melt-extruded and wrapped around the surface of the shielding layer material 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, and obtain a power cable after curing.

8. The process for preparing an environmentally friendly polypropylene insulated power cable according to claim 6, characterized in that: The compatibilizer in step S4 is PE-g-GMA compatibilizer.

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