Moisture-proof cable and preparation method thereof

Abstract

This invention discloses a moisture-proof cable and its manufacturing method, relating to the technical field of cables. A moisture-proof cable includes, from the inside out, a bundled cable tube, a waterproof membrane layer, a water-blocking braided layer, an armor tape layer, and an outer sheath. The waterproof membrane layer is formed by wrapping a composite moisture-proof membrane, one side of which has undergone corona treatment, around the outer periphery of the bundled cable tube. The water-blocking braided layer includes a braided layer and a waterproof coating. The braided layer is formed by weaving conductive fiber tape around the outer periphery of the waterproof membrane layer, while the waterproof coating is formed by fully impregnating and coating the braided layer with a waterproof coating and then curing it. By setting a waterproof membrane layer and a water-blocking braided layer containing a waterproof coating, combined with other conventional moisture-proof structures, the moisture-proof performance of the cable can be further improved, which is beneficial to improving the cable's safety performance and service life.

Description

Technical Field

[0001] This invention relates to the technical field of cables, and in particular to a moisture-proof cable and its manufacturing method. Background Technology

[0002] With the rapid development of the power industry and the acceleration of urbanization, power cables have been widely used in power systems due to their advantages such as not being limited by elevation differences, easy installation, laying, and maintenance, and have basically replaced traditional overhead power lines in cities.

[0003] Because cables often operate in various complex environments, such as high humidity, rainy coastal areas, and underwater environments, traditional ordinary cables have relatively low protective performance and are therefore easily corroded by moisture or water. When cables become damp or infiltrated by water, their insulation resistance decreases, leading to faults such as short circuits or insulation breakdowns, severely affecting their normal operation and service life. In coastal power grid faults, more than 35% of line faults are related to cables becoming damp and infiltrated.

[0004] Currently, some moisture-proof measures have been introduced for cables, such as using waterproof sleeves on the outside of the cable or directly using materials with excellent moisture-proof properties for the cable's outer sheath to improve its moisture resistance. However, for cables laid in confined spaces and subjected to prolonged pressure, both the waterproof sleeves on the cable's perimeter and the cable's outer sheath will gradually fatigue and age over time due to this pressure. This will significantly reduce the cable's moisture resistance, posing a safety hazard. Furthermore, in such environments, if the cable's insulation breaks down due to moisture, not only will repairs and replacement of the entire cable be necessary, but the limitations of the laying environment also present challenges such as high repair difficulty and cost. Therefore, providing a more effective and reliable moisture-proof method is of great significance to the development of the cable industry. Summary of the Invention

[0005] In order to improve the moisture resistance of cables, prevent short circuits or insulation breakdowns caused by environmental moisture or water seeping into the inner side of the cable, and improve the safety performance and service life of cables, this application provides a moisture-proof cable and its preparation method.

[0006] Firstly, the moisture-proof cable provided in this application adopts the following technical solution:

[0007] A moisture-proof cable includes, from the inside out, a bundled cable tube, a waterproof membrane layer, a water-blocking braided layer, an armor tape layer, and an outer sheath.

[0008] The waterproof membrane layer is formed by wrapping a composite moisture-proof membrane treated with corona on one side around the outer periphery of the bundled cable tube, with the corona-treated side of the composite moisture-proof membrane facing away from the bundled cable tube; the water-blocking braided layer includes a braided layer and a waterproof coating, the braided layer is formed by braiding conductive fiber tape around the outer periphery of the waterproof membrane layer, and the waterproof coating is formed by fully impregnating and coating the braided layer with waterproof paint and then curing it.

[0009] By adopting the above technical solution, and by setting a waterproof membrane layer and a water-blocking braided layer containing a waterproof coating, the moisture resistance of the cable can be effectively improved. Even if the cable is submerged in water for a long time, the moisture cannot fully penetrate into the interior of the bundled cable tube. This can effectively prevent short circuits or insulation breakdowns caused by environmental moisture or water seeping into the interior of the bundled cable tube, which is beneficial to improving the safety performance and service life of the cable.

[0010] Optionally, the composite moisture-proof film is prepared by casting from raw materials comprising the following parts by weight:

[0011] Polypropylene: 70-80 parts;

[0012] High-density polyethylene: 5-10 parts;

[0013] Maleic anhydride-grafted polypropylene: 3-7 parts;

[0014] Polyvinyl alcohol: 5-8 parts;

[0015] Ultrafine calcium carbonate: 20-30 parts;

[0016] Polyethylene oxide glyceryl monooleate: 1-2 parts;

[0017] Oleamide 0.1-0.3 parts.

[0018] By adopting the above technical solution, a waterproof and seepage-proof film can be produced. Combined with a water-blocking braided layer containing a waterproof coating, it is beneficial to improve the moisture-proof structure of the cable and enhance the moisture-proof performance and durability of the moisture-proof structure.

[0019] Optionally, the corona value of one side of the composite moisture-proof membrane treated with corona is 42-46 dynes.

[0020] By adopting the above technical solutions, it is beneficial to improve the bonding strength between the waterproof coating and the waterproof membrane layer, thereby improving the stability and durability of the cable moisture-proof structure, and enabling the cable to have good moisture-proof effect under both normal and pressure conditions.

[0021] Optionally, the waterproof coating is made by mixing the following raw materials in parts by weight:

[0022] Dual-cured polyurethane acrylate: 45-60 parts;

[0023] Epoxy acrylate: 20-35 parts;

[0024] Reactive diluent: 15-24 parts;

[0025] Photoinitiator: 3.6-4.8 parts;

[0026] Hydrophobic nanofiller: 12-20 parts;

[0027] The hydrophobic nanofiller is prepared by hydrophobizing the nanofiller with a silane coupling agent, and the nanofiller includes at least nano-silica.

[0028] Optionally, the epoxy acrylate is a mixture of bisphenol A epoxy acrylate and epoxy soybean oil acrylate, and the mixing mass ratio of the bisphenol A epoxy acrylate and epoxy soybean oil acrylate is (1-3):(3-4);

[0029] The active diluent is at least one of tripropylene glycol diacrylate and isobornyl methacrylate.

[0030] By adopting the above technical solution, a waterproof coating that can be cured by ultraviolet light and heat can be obtained. The waterproof coating formed after curing not only has good waterproof and seepage prevention performance, but also good flexibility and compressive strength. When combined with the braided layer, it can form a water-blocking braided layer with good structural stability and durability, which is conducive to improving the moisture-proof performance and moisture-proof structural durability of the cable.

[0031] Optionally, the hydrophobication treatment of the nanofiller includes the following steps:

[0032] A1. Heat and dry the nanofiller for at least 2 hours to obtain dehydrated nanofiller; dissolve the silane coupling agent in anhydrous ethanol and adjust the pH of the solution to 7.5-8 using ammonia to obtain an alkaline silane coupling agent solution.

[0033] A2. Place the dehydrated nanofiller in a high-speed disperser for high-speed dispersion, heat to 40-50℃ and simultaneously spray in a mist of alkaline silane coupling agent solution, and continuously stir the reaction for no less than 1 hour. After the reaction is completed, raise the temperature again to 60-65℃ and continuously stir for no less than 10 minutes to obtain the hydrophobic nanofiller.

[0034] By employing the above technical solution, the silane coupling agent is uniformly sprayed onto the nanofiller using a stirring spray method, which can uniformly form a silane coupling layer on the surface of the nanofiller, thus improving the hydrophobic modification effect of the silane coupling agent. Furthermore, pre-adjusting the silane coupling agent solution to alkaline using ammonia helps prevent the potential failure of metal powder contained in the nanofiller due to an acidic environment.

[0035] Optionally, the nanofiller further includes magnetically conductive powder, and the mass ratio of the nano-silica to the magnetically conductive powder is 10:(0.16-0.2).

[0036] Optionally, the magnetically conductive powder includes at least one of nano-iron powder or nano-flake nickel powder.

[0037] By adopting the above technical solution, the introduction of a small amount of magnetically conductive powder can significantly reduce the magnetic resistance and resistance of the waterproof coating. This not only effectively improves the low-frequency magnetic field shielding effect of the water-blocking shielding layer, but also, in conjunction with the braided layer made of conductive fiber tape, effectively improves the electric field shielding effect of the water-blocking braided layer, thereby improving the overall electromagnetic shielding performance of the moisture-proof cable.

[0038] Optionally, the active diluent is a mixture of tripropylene glycol diacrylate and isobornyl methacrylate in a mass ratio of (2-1):1.

[0039] By adopting the above technical solution, the introduction of isoborneol methacrylate can effectively improve the overall flexibility of the waterproof coating, reduce the negative impact of adding magnetic powder on the structural stability and durability of the waterproof coating, and thus help improve the durability of the cable moisture-proof structure, making it less susceptible to damage under pressure.

[0040] Optionally, the bundled cable tube includes an inner insulation layer, and cable cores, water-blocking ropes, and flame-retardant yarns disposed inside the inner insulation layer. The cable cores are arranged concentrically. The water-blocking ropes include a core rope and several outer ropes. The core ropes are disposed at the central axis of the cable cores, and the outer ropes are disposed between adjacent cable cores. The flame-retardant yarns fill the space between the cable cores and the water-blocking ropes.

[0041] By adopting the above technical solution, when the moisture-proof or protective structure on the outside of the bundled cable tube fails and moisture seeps into the inside of the bundled cable tube, the water-blocking rope and flame-retardant yarn can effectively prevent moisture from penetrating longitudinally within the bundled cable tube, thus preventing further penetration of moisture into the cable core. Furthermore, the structural cooperation between the water-blocking rope, flame-retardant yarn, and cable core ensures a compact internal structure of the bundled cable tube. Consequently, when the cable is subjected to mechanical stresses such as impact, bending, or tension, the bundled cable tube can effectively disperse stress and maintain the cable's shape. This helps prevent severe damage to the internal moisture-proof structure due to overall cable deformation, thereby improving the durability and reliability of the cable's moisture-proof structure.

[0042] Secondly, the method for preparing a moisture-proof cable provided in this application adopts the following technical solution:

[0043] A method for preparing a moisture-proof cable includes the following steps:

[0044] S1. Prepare the bundled cable tube in advance, and wrap the composite moisture-proof membrane around the outer periphery of the bundled cable tube to form a waterproof membrane layer.

[0045] S2. Conductive fiber tape is braided on the outer periphery of the waterproof membrane to form a braided layer. Then, the semi-finished cable with the braided layer is introduced into the waterproof coating in the dark and immersed in the waterproof coating. After being pulled out, the excess waterproof coating on the surface is scraped off. The cable is sent into a curing box for heating and is fully irradiated with ultraviolet light for no less than 5 minutes. After the waterproof coating is fully cured and a smooth waterproof coating is formed, a water-blocking braided layer is obtained.

[0046] S3. A thin metal sheet is wrapped around the outer periphery of the water-resistant braided layer to form an armor belt layer;

[0047] S4. Prepare an outer sheath to cover the outer periphery of the armor tape layer to obtain a moisture-proof cable.

[0048] By adopting the above technical solution, a cable with excellent moisture-proof performance can be produced. It not only provides sufficient waterproofing and seepage prevention under normal conditions, but also maintains excellent moisture-proof performance even after being subjected to pressure in multiple locations. Furthermore, the preparation method of the moisture-proof cable is simple, requiring only traditional winding equipment, braiding equipment, and ultraviolet curing ovens. This not only facilitates large-scale production in factories but also reduces the need for excessive investment in equipment upgrades, thus lowering the cost of technological improvements.

[0049] In summary, the technical solution of this application has at least one of the following beneficial effects:

[0050] 1. By setting a waterproof membrane layer and a water-blocking braided layer with a waterproof coating, combined with other conventional moisture-proof structures, the moisture-proof performance of the cable can be effectively improved, which is conducive to improving the safety performance and service life of the cable.

[0051] 2. By introducing a small amount of magnetically conductive powder into the water-blocking braided layer, not only can the low-frequency magnetic field shielding effect of the water-blocking shielding layer be effectively improved, but also, in conjunction with the braided layer made of conductive fiber tape, the electric field shielding effect of the water-blocking braided layer can be effectively improved, which in turn helps to improve the overall electromagnetic shielding performance of the moisture-proof cable.

[0052] 3. By introducing isoborneol methacrylate into the waterproof coating, the overall flexibility of the waterproof coating can be effectively improved, and the negative impact on the structural stability and durability of the waterproof coating caused by the addition of magnetic powder can be reduced, thereby improving the durability of the cable moisture-proof structure. Attached Figure Description

[0053] Figure 1 This is a cross-sectional view of a moisture-proof cable according to Embodiment 1 of this application.

[0054] Figure 2This is a side view of a moisture-proof cable according to Embodiment 1 of this application.

[0055] Explanation of reference numerals in the attached figures:

[0056] 1. Bundled cable conduit; 11. Inner insulation layer; 12. Cable core; 13. Water-blocking rope; 14. Flame-retardant yarn; 2. Waterproof membrane layer; 3. Water-blocking braided layer; 31. Braided layer; 32. Waterproof coating; 4. Armor tape layer; 5. Outer sheath. Detailed Implementation

[0057] The following is in conjunction with the appendix Figure 1-2 The preparation examples, embodiments, and comparative examples further illustrate this application in detail.

[0058] The dual-curing polyurethane acrylate was purchased from Bayer, Germany, with the brand name VPLS-2396.

[0059] Both the nano-iron powder and the nano-flaky nickel powder were purchased from Jinlei Technology. The nano-iron powder is grade JL-Fe-N80 with an average particle size of 80nm, and the nano-flaky nickel powder is grade JL-Ni-Y400 with an average particle size of 400nm.

[0060] Preparation Example

[0061]

Preparation Example 1-1

[0062] A composite moisture-proof film is prepared by mixing the following raw materials and then casting them: 70 kg polypropylene, 15 kg high-density polyethylene, 8 kg maleic anhydride-grafted polypropylene, 12 parts polyvinyl alcohol, 20 kg ultrafine calcium carbonate, 0.8 parts polyoxyethylene glycerol monooleate and 0.2 parts oleamide.

[0063] In this preparation example, one side of the composite moisture-proof film is also corona-treated, with a surface corona value of 42 dynes.

[0064]

Preparation Examples 1-2

[0065] A composite moisture-proof film is prepared by mixing the following raw materials and then casting them: 80 kg polypropylene, 10 kg high-density polyethylene, 4.5 kg maleic anhydride-grafted polypropylene, 5 parts polyvinyl alcohol, 25 kg ultrafine calcium carbonate, 1.2 parts polyoxyethylene glycerol monooleate and 0.3 parts oleamide.

[0066] In this preparation example, one side of the composite moisture-proof film is also corona-treated, with a surface corona value of 48 dynes.

[0067]

Preparation Examples 1-3

[0068] A composite moisture-proof film differs from [Preparation Example 1] in that the corona value on one side of the composite moisture-proof film is different.

[0069] In this preparation example, the surface corona value of the composite moisture-proof film after corona treatment is 54 dynes.

[0070]

Preparation Examples 1-4

[0071] A composite moisture-proof film differs from [Preparation Example 1] in that the composite moisture-proof film is not subjected to corona treatment.

[0072]

Preparation Example 2-1

[0073] A hydrophobic nanofiller is prepared by the following method:

[0074] A1. Heat 20 kg of nanofiller to 105℃ and dry it thoroughly for 2 hours to obtain dehydrated nanofiller; dissolve 1 kg of silane coupling agent KH570 in anhydrous ethanol at 5 wt%, and adjust the pH of the solution to 7.5-8 with ammonia water to obtain alkaline silane coupling agent solution.

[0075] A2. The dehydrated nanofiller was placed in a high-speed disperser for high-speed dispersion, heated to 40°C and simultaneously sprayed with a mist of alkaline silane coupling agent solution, and stirred continuously for 1 hour. After the reaction was completed, the temperature was raised to 65°C again and stirred continuously for 10 minutes to obtain the hydrophobic nanofiller.

[0076] In this preparation example, the nanofiller is nano-silica.

[0077]

Preparation Example 2-2

[0078] A hydrophobic nanofiller is prepared by the following method:

[0079] A1. Heat 20 kg of nanofiller to 105℃ and dry it thoroughly for 2 hours to obtain dehydrated nanofiller; dissolve 1 kg of silane coupling agent KH570 in anhydrous ethanol at 5 wt%, and adjust the pH of the solution to 7.5-8 with ammonia water to obtain alkaline silane coupling agent solution.

[0080] A2. The dehydrated nanofiller was placed in a high-speed disperser for high-speed dispersion, heated to 50°C and simultaneously sprayed with a mist of alkaline silane coupling agent solution, and stirred continuously for 1 hour. After the reaction was completed, the temperature was raised to 60°C again and stirred continuously for 15 minutes to obtain the hydrophobic nanofiller.

[0081] In this preparation example, the nanofiller is a mixture of nano-silica, nano-iron powder and nano-flake nickel powder. Specifically, the mass ratio of nano-silica, nano-iron powder and nano-flake nickel powder is 10:0.06:0.1, which includes 19.6 kg of nano-silica, 0.118 kg of nano-iron powder and 0.196 kg of nano-flake nickel powder.

[0082]

Preparation Examples 2-3

[0083] A hydrophobic nanofiller, which differs from the preparation example [2-1] in that it uses a different nanofiller.

[0084] In this preparation example, the nanofiller is a mixture of nano-silica, nano-iron powder and nano-flake nickel powder. Specifically, the mass ratio of nano-silica, nano-iron powder and nano-flake nickel powder is 10:0.1:0.1, which includes 19.6 kg of nano-silica, 0.196 kg of nano-iron powder and 0.196 kg of nano-flake nickel powder.

[0085]

Preparation Example 3-1

[0086] A waterproof coating is made by mixing the following raw materials:

[0087] 60 kg of dual-cured polyurethane acrylate, 20 kg of epoxy acrylate, 15 kg of reactive diluent, 3.6 kg of photoinitiator 1173, and 12 kg of hydrophobic nanofiller.

[0088] In this preparation example, the epoxy acrylate is a mixture of bisphenol A epoxy acrylate and epoxy soybean oil acrylate in a mass ratio of 1:3, that is, the epoxy acrylate includes 5 kg of bisphenol A epoxy acrylate and 15 kg of epoxy soybean oil acrylate; the reactive diluent is tripropylene glycol diacrylate; the hydrophobic nanofiller is specifically selected from the hydrophobic nanofiller prepared in [Preparation Example 2-1].

[0089]

Preparation Example 3-2

[0090] A waterproof coating is made by mixing the following raw materials:

[0091] 45 kg of dual-cured polyurethane acrylate, 35 kg of epoxy acrylate, 24 kg of reactive diluent, 4.8 kg of photoinitiator 1173, and 20 kg of hydrophobic nanofiller.

[0092] In this preparation example, the epoxy acrylate is a mixture of bisphenol A epoxy acrylate and epoxy soybean oil acrylate in a mass ratio of 3:4, that is, the epoxy acrylate includes 15 kg of bisphenol A epoxy acrylate and 20 kg of epoxy soybean oil acrylate; the reactive diluent is a mixture of tripropylene glycol diacrylate and isobornyl methacrylate in a mass ratio of 1:1, that is, it includes 12 kg of tripropylene glycol diacrylate and 12 kg of isobornyl methacrylate; the hydrophobic nanofiller is specifically selected from the hydrophobic nanofiller prepared in [Preparation Example 2-2].

[0093]

Preparation Example 3-3

[0094] A waterproof coating, which differs from [Preparation Example 3-1] in that it uses a different hydrophobic nanofiller.

[0095] In this preparation example, the hydrophobic nanofiller specifically selected is one of the hydrophobic nanofillers prepared in [Preparation Examples 2-3].

[0096]

Preparation Examples 3-4

[0097] A waterproof coating, which differs from [Preparation Example 3-3] in that it uses a different reactive diluent.

[0098] In this preparation example, the reactive diluent is a mixture of tripropylene glycol diacrylate and isobornyl methacrylate in a mass ratio of 2:1, which includes 10 kg of tripropylene glycol diacrylate and 5 kg of isobornyl methacrylate.

[0099] Example

[0100]

Example 1

[0101] A moisture-proof cable, as described in the reference Figure 1 and Figure 2 It includes, from the inside out, a bundled cable tube 1, a waterproof membrane layer 2, a water-blocking braided layer 3, an armor belt layer 4, and an outer sheath 5.

[0102] In this embodiment, refer to Figure 1 and Figure 2 The bundled cable tube 1 includes an inner insulation layer 11, cable cores 12 disposed inside the inner insulation layer 11, water-blocking ropes 13, and flame-retardant yarns 14. The cable cores 12 are arranged concentrically. The water-blocking ropes 13 include a core rope and several outer ropes. The core rope is disposed at the central axis of the cable core 12, and the several outer ropes are evenly distributed between adjacent cable cores 12. The flame-retardant yarns 14 fill the space between the cable cores 12 and the water-blocking ropes 13. The waterproof membrane layer 2 is formed by wrapping a composite moisture-proof membrane prepared in [Preparation Example 1-1] around the outer periphery of the bundled cable tube 1, with the corona-treated side of the composite moisture-proof membrane facing away from the bundled cable tube 1. The water-blocking braided layer 3 includes a braided layer 31 and a waterproof coating 32. The braided layer 31 is formed by braiding tin-plated copper strips around the outer periphery of the waterproof membrane layer 2. The waterproof coating 32 is formed by fully impregnating and coating the inner and outer surfaces of the braided layer 31 with a waterproof coating prepared in [Preparation Example 3-1] and then curing it. The armor belt layer 4 is formed by wrapping aluminum sheet around the outer periphery of the water-blocking braided layer 3, while the outer sheath 5 is formed by wrapping conventional insulating rubber around the outer periphery of the armor belt layer 4 through an extrusion coating process.

[0103] A method for preparing a moisture-proof cable includes the following steps:

[0104] S1. Prepare a bundled cable tube 1 in advance, and wrap a composite moisture-proof membrane around the outer periphery of the bundled cable tube 1 to form a waterproof membrane layer 2. The composite moisture-proof membrane has two layers, and the winding direction of each layer is different.

[0105] S2. Using tin-plated copper strips, weave the outer periphery of the waterproof membrane layer 2 at a weaving angle of 30° to form a woven layer 31. Then, the semi-finished product with the woven layer 31 is introduced into the waterproof coating in the dark and immersed in the waterproof coating. After being taken out, the excess waterproof coating on the surface is scraped off, and it is sent into a curing box and heated to 75°C and fully irradiated with ultraviolet light for 5 minutes. After the waterproof coating is fully cured and a smooth waterproof coating 32 is formed, the water-blocking woven layer 3 is obtained.

[0106] S3. Aluminum sheet is wound and wrapped around the outer periphery of the water-resistant braided layer 3 to form the armor belt layer 4.

[0107] S4. Prepare an outer sheath 5 to cover the outer periphery of the armor layer 4 to obtain a moisture-proof cable.

[0108]

Example 2

[0109] A moisture-proof cable, which differs from [Example 1] in that the waterproof membrane layer 2 and the water-blocking braided layer 3 are different.

[0110] In this embodiment, the waterproof membrane layer 2 is formed by wrapping a composite moisture-proof membrane prepared in [Preparation Examples 1-2] around the outer periphery of the bundled cable tube 1. The water-blocking braided layer 3 includes a braided layer 31 and a waterproof coating 32. The braided layer 31 is formed by braiding tin-plated copper strips around the outer periphery of the waterproof membrane layer 2. The waterproof coating 32 is formed by fully impregnating and coating the inner and outer surfaces of the braided layer 31 with a waterproof coating prepared in [Preparation Examples 3-2] and then curing it.

[0111]

Example 3

[0112] A moisture-proof cable, which differs from [Example 1] in that the waterproof membrane layer 2 is different.

[0113] In this embodiment, the waterproof membrane layer 2 is formed by wrapping a composite moisture-proof membrane prepared in [Preparation Examples 1-3] around the outer periphery of the bundled cable tube 1.

[0114]

Example 4

[0115] A moisture-proof cable, which differs from [Example 1] in that the water-blocking braided layer 3 is different.

[0116] In this embodiment, the waterproof coating 32 of the water-blocking braided layer 3 is formed by fully impregnating and coating the inner and outer surfaces of the braided layer 31 with a waterproof coating obtained in [Preparation Example 3-3] and then curing it.

[0117]

Example 5

[0118] A moisture-proof cable, which differs from [Example 1] in that the water-blocking braided layer 3 is different.

[0119] In this embodiment, the waterproof coating 32 of the water-blocking braided layer 3 is formed by fully impregnating and coating the inner and outer surfaces of the braided layer 31 with a waterproof coating obtained in [Preparation Examples 3-4] and then curing it.

[0120] Comparative Example

[0121] Comparative Example 1

[0122] A cable differs from [Example 1] in that it does not have a waterproof membrane layer 2 and a water-blocking braided layer 3.

[0123] In this comparative example, the cable consists of, from the inside out, a bundled cable tube 1, an armored tape layer 4, and an outer sheath 5.

[0124] Comparative Example 2

[0125] A cable that differs from [Example 1] in that the water-blocking braided layer 3 is different.

[0126] In this comparative example, the water-resistant braided layer 3 is not provided with a waterproof coating 32.

[0127] Comparative Example 3

[0128] A cable that differs from [Example 1] in that the waterproof membrane layer 2 is different.

[0129] In this comparative example, the waterproof membrane 2 is formed by wrapping a composite moisture-proof membrane obtained in [Preparation Examples 1-4] around the outer periphery of the bundled cable tube 1.

[0130] Performance test data

[0131] 1. Immersion voltage withstand test: Refer to section 5.4.1 of "T / CASME 354-2023 Moisture-proof Cable" for voltage withstand test. Specifically, take a 5m sample and immerse it in water at 20±5℃ for 60 days. Seal both ends of the cable and expose it above the water surface. After immersion, apply a 2.5kV voltage for 5 minutes and observe and record the cable breakdown.

[0132] 2. Moisture-proof structural durability: Take a 10m sample and divide it into 10 pressure points. Place the pressure points of the cable under test under the press. The press presses down at 10±1mm / min. Stop pressing when the pressing force reaches 3000N and press the next pressure point. After completing 10 pressure points, repeat the water immersion withstand voltage test and record the cable breakdown.

[0133] Table 1. Cable performance test data

[0134] Normal water immersion breakdown condition Multiple points of water immersion after being subjected to pressure resulted in breakdown. Example 1 Non-penetration Non-penetration Example 2 Non-penetration Non-penetration Example 3 Non-penetration breakdown Example 4 Non-penetration breakdown Example 5 Non-penetration Non-penetration Comparative Example 1 breakdown breakdown Comparative Example 2 Non-penetration breakdown Comparative Example 3 Non-penetration breakdown

[0135] Based on Example 1 and Comparative Example 1, and in conjunction with the data in Table 1, it can be seen that by setting a waterproof membrane layer 2 and a water-blocking braided layer 3 containing a waterproof coating 32, combined with other conventional moisture-proof structures, such as water-blocking ropes 13 and flame-retardant yarns 14 in the bundled cable tube 1, or an armored tape layer 4 formed of aluminum sheets, the moisture-proof performance of the cable can be effectively improved. Even though the cable is submerged in water for a long time, the moisture still cannot fully penetrate into the interior of the bundled cable tube 1. Therefore, the cable will not cause a short circuit or breakdown when connected to high voltage, which is beneficial to improving the safety performance and service life of the cable.

[0136] Based on the data in Example 1 and Comparative Example 2, and in conjunction with the data in Table 1, it can be seen that the waterproof coating 32 in the water-blocking braided layer 3 not only improves the moisture-proof performance of the cable, but also has a certain function of resisting pressure and maintaining the stability of the moisture-proof structure. It enables the cable to maintain a good moisture-proof structure and moisture-proof effect even after being subjected to pressure in multiple places, which is beneficial to improving the durability of the cable's moisture-proof structure.

[0137] Based on the data from Examples 1, 3, and Comparative Example 3, and referring to Table 1, it can be seen that the corona treatment of the composite moisture-proof membrane affects the moisture-proof structure of the cable. When the corona value of the composite moisture-proof membrane is 42-48 dynes, the stability and durability of the cable's moisture-proof structure are good, and it has a good moisture-proof effect. This may be because the surface of the untreated composite moisture-proof membrane has fewer polar molecules, resulting in low bonding strength between the polar waterproof coating and the waterproof membrane layer 2 when the waterproof coating 32 is applied. Under pressure, the cable is prone to damage to the moisture-proof structure. However, when the surface corona value is too high, it may cause the molecular chains on the surface of the composite moisture-proof membrane to break and form microcracks, thereby greatly reducing its barrier performance and mechanical properties. After the cable is subjected to pressure in multiple places, the moisture-proof structure is also prone to damage, affecting the final moisture-proof effect.

[0138] Based on Examples 1 and 4-5 and the data in Table 1, it can be seen that when a small amount of magnetic powder is added to the waterproof coating, although it can improve the low-frequency magnetic field shielding effect of the cable, it may reduce the flexibility of the waterproof coating 32, thereby affecting the durability of the cable's moisture-proof structure. In this case, the flexibility of the waterproof coating 32 can be improved by adjusting the composition of the active diluent in the waterproof coating, thereby improving the durability of the cable's moisture-proof structure and making it less susceptible to damage from compression.

[0139] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A moisture-proof cable, characterized in that: It includes, from the inside out, a bundled cable tube (1), a waterproof membrane layer (2), a water-blocking braided layer (3), an armor belt layer (4), and an outer sheath (5); The waterproof membrane layer (2) is formed by wrapping a composite moisture-proof membrane treated with corona on one side around the outer periphery of the bundled cable tube (1), and the side of the composite moisture-proof membrane treated with corona faces away from the bundled cable tube (1); the water-blocking braided layer (3) includes a braided layer (31) and a waterproof coating (32). The braided layer (31) is formed by braiding conductive fiber tape around the outer periphery of the waterproof membrane layer (2), and the waterproof coating (32) is formed by fully impregnating and coating the braided layer (31) with waterproof paint and then curing it. The waterproof coating is composed of the following raw materials in parts by weight: Dual-cured polyurethane acrylate: 45-60 parts; Epoxy acrylate: 20-35 parts; Reactive diluent: 15-24 parts; Photoinitiator: 3.6-4.8 parts; Hydrophobic nanofiller: 12-20 parts; The hydrophobic nanofiller is prepared by hydrophobizing the nanofiller with a silane coupling agent. The nanofiller includes nano-silica and magnetic powder. The mass ratio of the nano-silica and the magnetic powder is 10:(0.16-0.2). The active diluent is a mixture of tripropylene glycol diacrylate and isobornyl methacrylate in a mass ratio of (2-1):

1.

2. The moisture-proof cable according to claim 1, characterized in that: The composite moisture-proof film is prepared by casting from raw materials comprising the following parts by weight: Polypropylene: 70-80 parts; High-density polyethylene: 5-10 parts; Maleic anhydride-grafted polypropylene: 3-7 parts; Polyvinyl alcohol: 5-8 parts; Ultrafine calcium carbonate: 20-25 parts; Polyethylene oxide glyceryl monooleate: 1-2 parts; Oleamide: 0.1-0.3 parts.

3. A moisture-proof cable according to claim 2, characterized in that: The corona value of one side of the composite moisture-proof membrane treated with corona is 42-46 dynes.

4. A moisture-proof cable according to claim 1, characterized in that: The epoxy acrylate is a mixture of bisphenol A epoxy acrylate and epoxy soybean oil acrylate, and the mass ratio of the bisphenol A epoxy acrylate to the epoxy soybean oil acrylate is (1-3):(3-4).

5. A moisture-proof cable according to claim 1, characterized in that: The hydrophobication treatment of the nanofiller includes the following steps: A1. Heat and dry the nanofiller for at least 2 hours to obtain dehydrated nanofiller; dissolve the silane coupling agent in anhydrous ethanol and adjust the pH of the solution to 7.5-8 using ammonia to obtain an alkaline silane coupling agent solution. A2. Place the dehydrated nanofiller in a high-speed disperser for high-speed dispersion, heat to 40-50℃ and simultaneously spray in a mist of alkaline silane coupling agent solution, and continuously stir the reaction for no less than 1 hour. After the reaction is completed, raise the temperature again to 60-65℃ and continuously stir for no less than 10 minutes to obtain the hydrophobic nanofiller.

6. A moisture-proof cable according to claim 1, characterized in that: The bundled cable tube (1) includes an inner insulation layer (11), and a cable core (12), a water-blocking rope (13), and a flame-retardant yarn (14) disposed inside the inner insulation layer (11). The cable cores (12) are arranged concentrically. The water-blocking rope (13) includes a core rope and several outer ropes. The core rope is disposed at the central axis of the cable core (12). The outer ropes are disposed between adjacent cable cores (12). The flame-retardant yarn (14) fills the space between the cable core (12) and the water-blocking rope (13).

7. A method for preparing a moisture-proof cable, used to prepare a moisture-proof cable as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Prepare a bundled cable tube (1) in advance, and wrap the composite moisture-proof membrane around the outer periphery of the bundled cable tube (1) to form a waterproof membrane layer (2). S2. Conductive fiber tape is braided on the outer periphery of the waterproof membrane layer (2) to form a braided layer (31). Then, the semi-finished cable with the braided layer (31) is introduced into the waterproof coating in the dark and immersed in the waterproof coating. After being pulled out, the excess waterproof coating on the surface is scraped off. It is sent into the curing box for heating and fully irradiated with ultraviolet light for no less than 5 minutes. After the waterproof coating is fully cured and a smooth waterproof coating (32) is formed, the water-blocking braided layer (3) is obtained. S3. A metal sheet is wrapped around the outer periphery of the water-resistant braided layer (3) to form an armor belt layer (4). S4. Prepare an outer sheath (5) to cover the outer periphery of the armor tape layer (4) to obtain a moisture-proof cable.

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