Moisture-proof cable and preparation method thereof

Abstract

The invention discloses a moisture-proof cable and a preparation method thereof, and relates to the technical field of cables. A moisture-proof cable comprises a bundling cable pipe, a waterproof film layer, a water-blocking braid layer, an armor tape layer and an outer sheath which are sequentially arranged from inside to outside, the waterproof film layer is formed by winding and wrapping a composite moisture-proof film with one side subjected to corona treatment on the periphery of the bundling cable pipe, and the water-blocking braid layer comprises a braid layer and a waterproof coating. The braid layer is formed by weaving a conductive fiber band on the peripheral side of the waterproof film layer, and the waterproof coating is formed by fully infiltrating and coating the braid layer with waterproof paint and curing the waterproof paint. By arranging the waterproof film layer and the waterproof braid layer containing the waterproof coating and cooperating with other conventional moisture-proof structures, the moisture-proof performance of the cable can be further improved, the safety performance of the cable can be improved, and the service life of the cable can be prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and in particular to a moisture-proof cable and a preparation method thereof Background Art

[0002] With the rapid development of the electric power industry and the acceleration of urbanization, power cables have been widely used in power systems because of their advantages such as being free from drop restrictions, easy installation, laying, maintenance and protection, and have basically replaced traditional overhead wires in cities.

[0003] Because cables often operate in complex environments, such as high humidity, rainy coastal areas, and underwater, conventional cables lack robust protection and are therefore susceptible to moisture and water damage. When moisture or water ingress occurs, the insulation resistance of cables decreases, leading to faults such as short circuits or insulation breakdown, seriously impacting their normal operation and service life. Over 35% of power grid failures in coastal areas are related to moisture and water ingress.

[0004] Currently, some moisture-proofing measures for cables have been introduced on the market, such as using waterproof sleeves to cover the outside of the cable, or directly using materials with excellent moisture-proof properties for the cable's outer sheath to improve the cable's moisture-proof performance. However, for cables laid in small spaces and under pressure for a long time, due to long-term pressure, both the waterproof sleeves on the outer periphery of the cable and the outer sheath of the cable itself will gradually suffer fatigue and aging damage over time. At that time, the cable's moisture-proofness will inevitably be greatly reduced, posing certain safety hazards. Moreover, in such an environment, once the cable's insulation breaks down due to moisture, not only does it need to be repaired and replaced as a whole, but it is also limited by the laying environment and has problems such as high difficulty and high cost in repair. Therefore, providing a more effective and reliable moisture-proofing 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 breakdown caused by environmental moisture or water penetrating into the inner side of the cables, and improve the safety performance and service life of the cables, the present application provides a moisture-proof cable and a preparation method thereof.

[0006] In the first aspect, the present application provides a moisture-proof cable adopting the following technical solution: A moisture-proof cable comprises a bundled cable tube, a waterproof membrane layer, a water-blocking braided layer, an armored tape layer and an outer sheath, which are sequentially arranged from the inside to the outside. Among them, the waterproof membrane layer is formed by winding a composite moisture-proof membrane with one side corona-treated and covering the outer peripheral side of the bundled cable tube, and the corona-treated side of the composite moisture-proof membrane faces the side 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 a conductive fiber tape on the outer peripheral side of the waterproof membrane layer, and the waterproof coating is formed by fully infiltrating and coating the braided layer with a waterproof coating and curing it.

[0007] By adopting the above technical solution, by providing a waterproof membrane layer and a water-blocking braided layer containing a waterproof coating, the moisture-proof performance of the cable can be effectively improved. Even if the cable is immersed in water for a long time, moisture cannot fully penetrate into the interior of the bundled cable tube, which can effectively prevent short circuits or insulation breakdown caused by environmental moisture or moisture penetrating into the inner side of the bundled cable tube, which is beneficial to improving the safety performance and service life of the cable.

[0008] Optionally, the composite moisture-proof film is prepared by casting the following raw materials in 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: 20-30 parts; Polyethylene oxide glycerol monooleate: 1-2 parts; Oleamide 0.1-0.3 parts.

[0009] By adopting the above technical solution, a waterproof and anti-seepage film can be produced, which, combined with a water-blocking braided layer containing a waterproof coating, is beneficial to improving the moisture-proof structure of the cable and enhancing the moisture-proof performance and durability of the cable.

[0010] Optionally, the corona value of the corona-treated surface of one side of the composite moisture-proof film is 42-46 dynes.

[0011] By adopting the above technical solution, it is beneficial to improve the bonding strength between the waterproof coating and the waterproof membrane layer, thereby helping to improve the stability and durability of the cable moisture-proof structure, and enable the cable to have good moisture-proof effect both under normal conditions and under pressure.

[0012] Optionally, the waterproof coating is prepared by mixing the following raw materials in parts by weight: Dual-cure polyurethane acrylate: 45-60 parts; Epoxy acrylate: 20-35 parts; Active diluent: 15-24 parts; Photoinitiator: 3.6-4.8 parts; Hydrophobized nanofiller: 12-20 parts; The hydrophobized nanofiller is prepared by subjecting the nanofiller to a hydrophobic treatment with a silane coupling agent, and the nanofiller at least includes nano-silicon dioxide.

[0013] 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 the epoxy soybean oil acrylate is (1-3): (3-4); The active diluent is at least one of tripropylene glycol diacrylate and isobornyl methacrylate.

[0014] By adopting the above technical solution, a waterproof coating that can be cured by ultraviolet light and heat can be produced. At the same time, the waterproof coating formed after curing not only has good waterproof and anti-seepage properties, but also has good flexibility and compressive resistance. Combined with the braided layer, it can form a water-blocking braided layer with good structural stability and durability, which is beneficial to improving the moisture-proof performance of the cable and the durability of the moisture-proof structure.

[0015] Optionally, the hydrophobization treatment of the nanofiller comprises the following steps: A1. Heating and fully drying the nanofiller for not less than 2 hours to obtain a dehydrated nanofiller; dissolving a silane coupling agent in anhydrous ethanol, and adjusting the pH of the solution to 7.5-8 with aqueous 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°C and simultaneously spray in a mist of alkaline silane coupling agent solution, continue stirring and react for not less than 1 hour, and after the reaction is completed, heat again to 60-65°C and continue stirring for not less than 10 minutes to obtain a hydrophobic nanofiller.

[0016] By adopting the above technical solution, the silane coupling agent is evenly sprayed onto the nanofiller using a stirring spray method, forming a uniform silane coupling layer on the surface of the nanofiller, which helps to enhance the hydrophobic modification effect of the silane coupling agent. In addition, the silane coupling agent solution is pre-adjusted to an alkaline state using ammonia water, which helps prevent the metal powder contained in the nanofiller from being degraded due to the acidic environment.

[0017] Optionally, the nano-filler further includes magnetic conductive powder, and the mixing mass ratio of the nano-silicon dioxide to the magnetic conductive powder is 10:(0.16-0.2).

[0018] Optionally, the magnetic conductive powder includes at least one of nano iron powder or nano flaky nickel powder.

[0019] By adopting the above technical solution, the introduction of a small amount of magnetic conductive powder can significantly reduce the magnetic resistance and electrical resistance of the waterproof coating, which can not only effectively improve the low-frequency magnetic field shielding effect of the water-blocking shielding layer, but also, in combination with the braided layer woven by conductive fiber tapes, can effectively improve the electric field shielding effect of the water-blocking braided layer, thereby helping to improve the comprehensive electromagnetic shielding performance of the moisture-proof cable.

[0020] Optionally, the active diluent is a mixture of tripropylene glycol diacrylate and isobornyl methacrylate in a mass ratio of (2-1):1.

[0021] By adopting the above-mentioned technical solution, the introduction of isobornyl methacrylate can effectively improve the overall flexibility of the waterproof coating, reduce the negative impact on the structural stability and durability of the waterproof coating caused by the addition of magnetic conductive powder, and thus help improve the durability of the cable moisture-proof structure and make it less likely to be damaged by pressure.

[0022] Optionally, the bundled cable tube includes an inner insulating layer, and a cable core, a water-blocking rope and a flame-retardant yarn arranged on the inner side of the inner insulating layer. The cable core is arranged in a concentric manner. The water-blocking rope includes a core rope and several outer ropes. The core rope is arranged at the central axis of the cable core, the outer rope is arranged between adjacent cable cores, and the flame-retardant yarn is filled between the cable core and the water-blocking rope.

[0023] By adopting the above technical solution, when the moisture-proof structure or protective structure on the outside of the bundled cable tube fails and moisture penetrates into the bundled cable tube, the water-blocking rope and flame-retardant yarn can also effectively prevent moisture from penetrating longitudinally within the bundled cable tube, which helps prevent moisture from further penetrating into the cable core. In addition, the structural interaction between the water-blocking rope, flame-retardant yarn and cable core makes the internal structure of the bundled cable tube tight. When the cable is subjected to external force, such as impact, bending or stretching, the bundled cable tube can effectively disperse the stress and maintain the shape of the cable, which helps prevent serious damage to the internal moisture-proof structure due to overall cable deformation, and helps improve the durability and reliability of the cable moisture-proof structure.

[0024] In a second aspect, the present application provides a method for preparing a moisture-proof cable using the following technical solution: A method for preparing a moisture-proof cable comprises the following steps: S1. Prepare a bundled cable tube in advance, and wrap the composite moisture-proof membrane around the outer circumference of the bundled cable tube to form a waterproof membrane layer; S2. A conductive fiber tape is braided on the outer periphery of the waterproof membrane layer to form a braided layer. The semi-finished cable with the braided layer is then introduced into the waterproof coating in a dark place. After the semi-finished cable is introduced, excess waterproof coating is scraped off the surface. The cable is then placed into a curing box for heating and irradiation with ultraviolet light for at least 5 minutes. The waterproof coating is fully cured to form a smooth waterproof coating, thereby obtaining a water-blocking braided layer. S3, wrapping a metal sheet around the outer periphery of the water-blocking braided layer to form an armor tape layer; S4. Prepare an outer sheath and cover it on the outer peripheral side of the armor tape layer to obtain a moisture-proof cable.

[0025] By adopting the above technical solution, a cable with excellent moisture-proof properties can be produced. It is not only fully waterproof and anti-seepage under normal conditions, but also maintains excellent moisture-proof performance after being subjected to multiple pressure points. In addition, the preparation method of the moisture-proof cable is simple, requiring only traditional winding equipment, braiding equipment, and a UV curing oven. This not only facilitates subsequent large-scale production in factories, but also does not require excessive investment in equipment improvements, which helps reduce the cost of technical improvements.

[0026] In summary, the technical solution of this application has at least one of the following beneficial effects: 1. By setting up 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 effectively improved, which is beneficial to improving the safety performance and service life of the cable.

[0027] 2. By introducing a small amount of magnetic 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 combination with the braided layer woven by the conductive fiber tape, the electric field shielding effect of the water-blocking braided layer can be effectively improved, thereby improving the comprehensive electromagnetic shielding performance of the moisture-proof cable.

[0028] 3. By introducing isobornyl methacrylate into the waterproof coating, the overall flexibility of the waterproof coating can be effectively improved, and the negative impact of the addition of magnetic powder on the structural stability and durability of the waterproof coating can be reduced, thereby improving the durability of the cable moisture-proof structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a cross-sectional view of a moisture-proof cable in Example 1 of the present application.

[0030] Figure 2 This is a side structural diagram of a moisture-proof cable in Example 1 of the present application.

[0031] Description of reference numerals: 1. Bundled cable tube; 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. Armored tape layer; 5. Outer sheath. DETAILED DESCRIPTION

[0032] The following is combined with Figure 1-2 , preparation examples, embodiments and comparative examples are provided to further illustrate this application in detail.

[0033] The dual-curing polyurethane acrylate was purchased from Bayer, Germany, with the brand name VPLS-2396.

[0034] Nano iron powder and nano flaky nickel powder were purchased from Jinlei Technology. The brand of nano iron powder is JL-Fe-N80 with an average particle size of 80 nm, and the brand of nano flaky nickel powder is JL-Ni-Y400 with an average particle size of 400 nm.

[0035] Preparation Example [Preparation Example 1-1] A composite moisture-proof film is prepared by mixing the following raw materials through a casting process: 70 kg of polypropylene, 15 kg of high-density polyethylene, 8 kg of maleic anhydride-grafted polypropylene, 12 parts of polyvinyl alcohol, 20 kg of ultrafine calcium carbonate, 0.8 parts of polyethylene oxide glycerol monooleate, and 0.2 parts of oleamide.

[0036] In this preparation example, one side of the composite moisture-proof film is also subjected to corona treatment, wherein the surface corona value is 42 dynes.

[0037] [Preparation Example 1-2] A composite moisture-proof film is prepared by mixing the following raw materials through a casting process: 80 kg of polypropylene, 10 kg of high-density polyethylene, 4.5 kg of maleic anhydride-grafted polypropylene, 5 parts of polyvinyl alcohol, 25 kg of ultrafine calcium carbonate, 1.2 parts of polyethylene oxide glycerol monooleate, and 0.3 parts of oleamide.

[0038] In this preparation example, one side of the composite moisture-proof film is also subjected to corona treatment, wherein the surface corona value is 48 dynes.

[0039] [Preparation Examples 1-3] A composite moisture-proof film, which differs from [Preparation Example 1] in that the corona value of one side of the composite moisture-proof film is different.

[0040] In this preparation example, the surface corona value of the composite moisture-proof film after corona treatment is 54 dynes.

[0041] [Preparation Examples 1-4] A composite moisture-proof film, which differs from [Preparation Example 1] in that the composite moisture-proof film is not subjected to corona treatment.

[0042] [Preparation Example 2-1] A hydrophobized nanofiller is prepared by the following preparation method: A1. Heat 20 kg of nanofiller to 105° C. and fully dry and dehydrate for 2 h to obtain a 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 aqueous 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°C and simultaneously spray in a mist of alkaline silane coupling agent solution, continue stirring and react for 1 hour, and after the reaction is completed, heat again to 65°C and continue stirring for 10 minutes to obtain a hydrophobic nanofiller.

[0043] In this preparation example, the nanofiller is nano-silicon dioxide.

[0044] [Preparation Example 2-2] A hydrophobized nanofiller is prepared by the following preparation method: A1. Heat 20 kg of nanofiller to 105° C. and fully dry and dehydrate for 2 h to obtain a 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 aqueous 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 50°C and simultaneously spray a mist of alkaline silane coupling agent solution, continue stirring and react for 1 hour, and after the reaction is completed, heat again to 60°C and continue stirring for 15 minutes to obtain a hydrophobic nanofiller.

[0045] In this preparation example, the nanofiller is a mixture of nano-silicon dioxide, nano-iron powder and nano-flaky nickel powder. Specifically, the mixing mass ratio of nano-silicon dioxide, nano-iron powder and nano-flaky nickel powder is 10:0.06:0.1, that is, it includes 19.6 kg of nano-silicon dioxide, 0.118 kg of nano-iron powder and 0.196 kg of nano-flaky nickel powder.

[0046] [Preparation Example 2-3] A hydrophobic nanofiller, which differs from Preparation Example [2-1] in the difference in the nanofiller.

[0047] In this preparation example, the nanofiller is a mixture of nano-silicon dioxide, nano-iron powder and nano-flaky nickel powder. Specifically, the mixing mass ratio of nano-silicon dioxide, nano-iron powder and nano-flaky nickel powder is 10:0.1:0.1, that is, it includes 19.6 kg of nano-silicon dioxide, 0.196 kg of nano-iron powder and 0.196 kg of nano-flaky nickel powder.

[0048] [Preparation Example 3-1] A waterproof coating comprising a mixture of the following raw materials: 60kg dual-cure polyurethane acrylate, 20kg epoxy acrylate, 15kg reactive diluent, 3.6kg photoinitiator 1173 and 12kg hydrophobized nanofiller.

[0049] 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 active diluent is tripropylene glycol diacrylate; and the hydrophobic nanofiller is specifically selected from a hydrophobic nanofiller prepared in [Preparation Example 2-1].

[0050] [Preparation Example 3-2] A waterproof coating comprising a mixture of the following raw materials: 45 kg dual-cure polyurethane acrylate, 35 kg epoxy acrylate, 24 kg reactive diluent, 4.8 kg photoinitiator 1173 and 20 kg hydrophobized nanofiller.

[0051] 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 active 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 a hydrophobic nanofiller prepared in [Preparation Example 2-2].

[0052] [Preparation Example 3-3] A waterproof coating, which differs from [Preparation Example 3-1] in that the hydrophobic nanofiller is different.

[0053] In this preparation example, the hydrophobized nanofiller is specifically selected from the hydrophobized nanofiller prepared in [Preparation Example 2-3].

[0054] [Preparation Example 3-4] A waterproof coating, which differs from [Preparation Example 3-3] in that the active diluent is different.

[0055] In this preparation example, the active diluent is a mixture of tripropylene glycol diacrylate and isobornyl methacrylate in a mass ratio of 2:1, that is, including 10 kg of tripropylene glycol diacrylate and 5 kg of isobornyl methacrylate. Example

[0056] [Example 1] A moisture-proof cable, referring to Figure 1 and Figure 2, including a bundled cable tube 1, a waterproof membrane layer 2, a water-blocking braided layer 3, an armored tape layer 4 and an outer sheath 5, which are arranged in sequence from the inside to the outside.

[0057] In this embodiment, referring to Figure 1 and Figure 2 The bundled cable tube 1 comprises an inner insulating layer 11, a cable core 12 disposed inside the inner insulating layer 11, a water-blocking rope 13, and a flame-retardant yarn 14. The cable cores 12 are arranged concentrically. The water-blocking rope 13 comprises a core rope and a plurality of outer ropes. The core rope is disposed at the central axis of the cable core 12, and the outer ropes are evenly distributed between adjacent cable cores 12. The flame-retardant yarn 14 is filled between the cable core 12 and the water-blocking rope 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 comprises a braided layer 31 and a waterproof coating 32. The braided layer 31 is formed by woven tinned copper tape around the outer periphery of the waterproof membrane 2. The waterproof coating 32 is formed by thoroughly impregnating and curing the inner and outer surfaces of the braided layer 31 with a waterproof coating prepared in [Preparation Example 3-1]. The armor tape layer 4 is formed by wrapping aluminum sheets around the outer periphery of the water-blocking braided layer 3 , and the outer sheath 5 is formed by wrapping conventional insulating rubber around the outer periphery of the armor tape layer 4 through an extrusion coating process.

[0058] A method for preparing a moisture-proof cable comprises the following steps: S1. Prepare a bundled cable tube 1 in advance, and wrap a composite moisture-proof membrane around the outer circumference of the bundled cable tube 1 to form a waterproof membrane layer 2. The composite moisture-proof membrane is wound in two layers, and the winding direction of each layer is different. S2. Tinned copper tape is braided at a braiding angle of 30° around the outer periphery of the waterproof membrane layer 2 to form a braided layer 31. The semi-finished product with the braided layer 31 is then introduced into a waterproof coating in a dark place. After being introduced, excess waterproof coating is scraped off the surface. The semi-finished product is then placed into a curing oven, heated to 75°C, and irradiated with ultraviolet light for 5 minutes. The waterproof coating is fully cured to form a smooth waterproof coating 32, thereby obtaining a water-blocking braided layer 3. S3, wrapping aluminum sheets around the outer periphery of the water-blocking braided layer 3 to form an armored tape layer 4; S4. Prepare an outer sheath 5 and cover it on the outer peripheral side of the armor tape layer 4 to obtain a moisture-proof cable.

[0059] [Example 2] 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.

[0060] In this embodiment, waterproof membrane layer 2 is formed by wrapping a composite moisture-proof membrane prepared in [Preparation Example 1-2] around the outer periphery of cluster cable tube 1. Water-blocking braided layer 3 includes a braided layer 31 and a waterproof coating 32. Braided layer 31 is formed by woven tinned copper tape around the outer periphery of waterproof membrane layer 2. Waterproof coating 32 is formed by fully impregnating and coating the inner and outer surfaces of braided layer 31 with a waterproof coating prepared in [Preparation Example 3-2] and then curing.

[0061] [Example 3] A moisture-proof cable, which differs from [Example 1] in that the waterproof membrane layer 2 is different.

[0062] In this embodiment, the waterproof membrane layer 2 is formed by winding a composite moisture-proof membrane prepared in [Preparation Example 1-3] around the outer circumference of the bundled cable tube 1 .

[0063] [Example 4] A moisture-proof cable, which differs from [Example 1] in that the water-blocking braided layer 3 is different.

[0064] In this embodiment, the waterproof coating 32 of the water-blocking braided layer 3 is formed by fully infiltrating and coating the inner and outer surfaces of the braided layer 31 with a waterproof coating prepared in [Preparation Example 3-3] and then curing it.

[0065] [Example 5] A moisture-proof cable, which differs from [Example 1] in that the water-blocking braided layer 3 is different.

[0066] In this embodiment, the waterproof coating 32 of the water-blocking braided layer 3 is formed by fully infiltrating and coating the inner and outer surfaces of the braided layer 31 with a waterproof coating prepared in [Preparation Example 3-4] and then curing it.

[0067] Comparative Example [Comparative Example 1] A cable, which differs from [Example 1] in that it does not have a waterproof membrane layer 2 and a water-blocking braided layer 3.

[0068] In this comparative example, the cable comprises a bundled cable tube 1, an armored tape layer 4 and an outer sheath 5 from the inside out.

[0069] [Comparative Example 2] A cable, which differs from [Example 1] in that the water-blocking braided layer 3 is different.

[0070] In this comparative example, the water-blocking braided layer 3 is not provided with the waterproof coating 32 .

[0071] [Comparative Example 3] A cable, which differs from [Example 1] in that the waterproof membrane layer 2 is different.

[0072] In this comparative example, the waterproof membrane layer 2 is formed by winding and covering the outer circumference of the bundled cable tube 1 with a composite moisture-proof membrane prepared in [Preparation Example 1-4].

[0073] Performance test data 1. Water immersion voltage withstand test: Refer to 5.4.1 Voltage withstand test in T / CASME 354-2023 Moisture-resistant Cable for the test. Specifically, take a 5m sample and immerse it in water at 20±5℃ for 60 days. Both ends of the cable are sealed and exposed to the water surface. After the immersion, connect a 2.5kV voltage for 5 minutes, and observe and record the cable breakdown.

[0074] 2. Durability of moisture-proof structure: Take 10m sample and evenly divide it into 10 pressure points. Place the pressure point of the cable to be tested under the press. Press downward at 10±1mm / min. Stop squeezing when the squeezing force reaches 3000N and squeeze the next pressure point. After completing 10 pressure points, repeat the immersion voltage test again and record the cable breakdown.

[0075] Table 1 Cable performance test data Normal water immersion breakdown Water immersion and breakdown after multiple pressure Example 1 No breakdown No breakdown Example 2 No breakdown No breakdown Example 3 No breakdown breakdown Example 4 No breakdown breakdown Example 5 No breakdown No breakdown Comparative Example 1 breakdown breakdown Comparative Example 2 No breakdown breakdown Comparative Example 3 No breakdown breakdown Combining Example 1 and Comparative Example 1 and the data in Table 1, it can be seen that by providing a waterproof membrane layer 2 and a water-blocking braided layer 3 containing a waterproof coating 32, in combination with other conventional moisture-proof structures, such as the water-blocking rope 13 and the flame-retardant yarn 14 in the bundled cable tube 1, or the armored tape layer 4 formed by aluminum foil, the moisture-proof performance of the cable can be effectively improved. Although the cable is immersed 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 electricity, which is beneficial to improving the safety performance and service life of the cable.

[0076] Combining Example 1 and Comparative Example 2 and 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 pressure resistance and maintains the stability of the moisture-proof structure. It can enable the cable to maintain a good moisture-proof structure and moisture-proof effect after being pressurized in multiple places, which is beneficial to improving the durability of the cable's moisture-proof structure.

[0077] Combining Example 1, Example 3, and Comparative Example 3 with the data in Table 1, it can be seen that the corona treatment of the composite moisture-proof film will affect the moisture-proof structure of the cable. When the corona value of the composite moisture-proof film is 42-48 dynes, the stability and durability of the moisture-proof structure of the cable are both good, and it has a good moisture-proof effect. This may be because the surface polar molecules of the composite moisture-proof film that has not been corona treated are relatively small, so that when the waterproof coating 32 is wetted and coated, the bonding strength between the polar waterproof coating and the waterproof membrane layer 2 is not high, and the cable is easily damaged by moisture-proof structure when under pressure. However, when the surface corona value is too high, it may cause the molecular chain on the surface of the composite moisture-proof film to break and form microcracks, thereby greatly reducing its barrier performance and mechanical properties. After the cable is subjected to multiple pressures, it is also easy to cause damage to the moisture-proof structure and affect the final moisture-proof effect.

[0078] Combining Example 1, Examples 4-5 and the data in Table 1, it can be seen that when a small amount of magnetic conductive powder is added to the waterproof coating, although the low-frequency magnetic field shielding effect of the cable can be improved, the flexibility of the waterproof coating 32 may be reduced, thereby affecting the durability of the moisture-proof structure of the cable. At this time, the flexibility of the waterproof coating 32 can be improved by adjusting the component of the active diluent in the waterproof coating, thereby improving the durability of the moisture-proof structure of the cable and making it less likely to be squeezed and damaged.

[0079] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A moisture-proof cable, characterized in that: It comprises a bundled cable tube (1), a waterproof membrane layer (2), a water-blocking braided layer (3), an armored tape layer (4), and an outer sheath (5) which are arranged in sequence from the inside out. The waterproof membrane layer (2) is formed by wrapping a composite moisture-proof membrane with one side subjected to corona treatment around the outer peripheral side of the bundled cable tube (1), and the corona-treated side of the composite moisture-proof membrane faces the side away from the bundled cable tube (1); the water-blocking braided layer (3) comprises a braided layer (31) and a waterproof coating (32), the braided layer (31) is formed by braiding a conductive fiber tape around the outer peripheral side of the waterproof membrane layer (2), and the waterproof coating (32) is formed by fully impregnating and coating the braided layer (31) with a waterproof coating and then curing it.

2. A moisture-proof cable according to claim 1, characterized in that: The composite moisture-proof film is prepared by casting the following raw materials in 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 glycerol 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 the corona-treated surface of the composite moisture-proof film is 42-46 dynes.

4. The moisture-proof cable according to claim 1, characterized in that: The waterproof coating is prepared by mixing the following raw materials in parts by weight: Dual-cure polyurethane acrylate: 45-60 parts; Epoxy acrylate: 20-35 parts; Active diluent: 15-24 parts; Photoinitiator: 3.6-4.8 parts; Hydrophobized nanofiller: 12-20 parts; The hydrophobized nanofiller is prepared by subjecting the nanofiller to a hydrophobic treatment with a silane coupling agent, and the nanofiller at least includes nano-silicon dioxide.

5. A moisture-proof cable according to claim 4, characterized in that: 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 the epoxy soybean oil acrylate is (1-3): (3-4); The active diluent is at least one of tripropylene glycol diacrylate and isobornyl methacrylate.

6. The moisture-proof cable according to claim 4, characterized in that: The hydrophobization treatment of the nanofiller comprises the following steps: A1. Heating and fully drying the nanofiller for not less than 2 hours to obtain a dehydrated nanofiller; dissolving a silane coupling agent in anhydrous ethanol, and adjusting the pH of the solution to 7.5-8 with aqueous 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°C and simultaneously spray in a mist of alkaline silane coupling agent solution, continue stirring and react for not less than 1 hour, and after the reaction is completed, heat again to 60-65°C and continue stirring for not less than 10 minutes to obtain a hydrophobic nanofiller.

7. The moisture-proof cable according to claim 4, characterized in that: The nano filler also includes magnetic conductive powder, and the mixing mass ratio of the nano silicon dioxide to the magnetic conductive powder is 10:(0.16-0.2).

8. The moisture-proof cable according to claim 7, characterized in that: The active diluent is a mixture of tripropylene glycol diacrylate and isobornyl methacrylate in a mass ratio of (2-1):

1.

9. The moisture-proof cable according to claim 1, characterized in that: The bundled cable tube (1) comprises an inner insulating layer (11), a cable core (12), a water-blocking rope (13) and a flame-retardant yarn (14) arranged on the inner side of the inner insulating layer (11); the cable core (12) is arranged in a concentric arrangement; the water-blocking rope (13) comprises a core rope and a plurality of outer ropes; the core rope is arranged at the central axis of the cable core (12); the outer rope is arranged between adjacent cable cores (12); and the flame-retardant yarn (14) is filled between the cable core (12) and the water-blocking rope (13).

10. A method for preparing a moisture-proof cable, for preparing a moisture-proof cable according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, pre-preparing a bundled cable tube (1), and wrapping a composite moisture-proof membrane around the outer circumference of the bundled cable tube (1) to form a waterproof membrane layer (2); S2, using a conductive fiber tape to weave the outer peripheral side of the waterproof membrane layer (2) to form a braided layer (31), then introducing the semi-finished cable with the braided layer (31) in the dark and immersing it in the waterproof coating, scraping off excess waterproof coating on the surface after leading it out, and sending it into a curing box to be heated and fully irradiated with ultraviolet light for not less than 5 minutes, until the waterproof coating is fully cured and forms a smooth waterproof coating (32), thereby obtaining a water-blocking braided layer (3); S3, wrapping a metal sheet around the outer periphery of the water-blocking braided layer (3) to form an armored tape layer (4); S4. Prepare an outer sheath (5) and cover it on the outer peripheral side of the armor tape layer (4) to obtain a moisture-proof cable.

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