Moisture-proof and explosion-proof cable and preparation method thereof

Abstract

The application provides a damp-proof and explosion-proof cable and a preparation method thereof, and relates to the technical field of cables.The damp-proof and explosion-proof cable provided by the application comprises a cable core formed by a plurality of conductive cores being wound in the same direction, an insulating shielding layer is arranged outside the cable core, and a filling layer is formed outside the insulating shielding layer; a plurality of armored layers are arranged outside the filling isolation layer, a protective layer is filled between the plurality of armored layers, and the armored layer located at the outermost layer is provided with a cable sheath; the protective layer contains a heat-conducting and flame-retardant body, and the heat-conducting and flame-retardant body is a carbon matrix doped with aluminum hydroxide nanoparticles on the surface.The damp-proof and explosion-proof cable provided by the application can improve the damp-proof and explosion-proof performance of the cable.

Description

Technical Field

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

[0002] In many industrial sectors such as petrochemicals, coal mining, and natural gas transportation, the production environments are extremely complex and contain large amounts of flammable and explosive gases, posing a serious threat to the safety and stability of power transmission cables. For example, when power transmission cables are exposed to a humid environment for extended periods, moisture seeps into the cable sheath, easily causing discharge and potentially leading to gas explosions and production accidents. Therefore, moisture-proof and explosion-proof cables are crucial equipment for ensuring the safe and orderly operation of production activities. They not only maintain the normal operation of various electrical devices but also serve as a vital line of defense for personnel safety and the integrity of production facilities. If the performance of moisture-proof and explosion-proof cables is insufficient, the resulting losses can be incalculable.

[0003] Currently, commonly used moisture-proof and explosion-proof cables consist of, from the inside out, a metal conductor, an insulation layer, a moisture-proof layer, and an explosion-proof armor layer. The metal conductor serves as the core channel for current transmission, while the insulation layer provides insulation protection to the metal conductor, preventing leakage. The moisture-proof layer and the explosion-proof armor layer protect the insulation layer, preventing leakage caused by insulation rupture. In addition, the moisture-proof layer and the explosion-proof armor layer respectively provide moisture protection and explosion protection. The armor layer, with its metal structure, enhances the structural strength of the moisture-proof and explosion-proof cable.

[0004] However, although moisture-proof and explosion-proof cables improve their moisture-proof performance by setting a moisture-proof layer, moisture can easily seep into the surface when the cable is used in a high-humidity environment for a long time. This is especially true when the cable is subjected to external pressure or when defects such as creases or damage occur on the surface during installation. This can lead to a decrease in insulation performance and affect the integrity of the armor layer inside the cable. Consequently, arcing may occur during cable use, increasing the risk of explosion. Therefore, there is an urgent need to provide a solution to improve these problems. Summary of the Invention

[0005] The purpose of this invention is to provide a moisture-proof and explosion-proof cable and its preparation method.

[0006] In a first aspect, the present invention provides a moisture-proof and explosion-proof cable, comprising a cable core formed by multiple conductive cores wound in the same direction, wherein an insulating shielding layer is sleeved on the outside of the cable core, and a filling layer is formed on the outside of the insulating shielding layer; multiple armor layers are disposed on the outside of the filling shielding layer, a protective layer is filled between the multiple armor layers, and a cable sheath is sleeved on the outermost armor layer; wherein the protective layer contains a thermally conductive and flame-retardant body, the thermally conductive and flame-retardant body being a carbon matrix with aluminum hydroxide nanoparticles doped on its surface.

[0007] The moisture-proof and explosion-proof cable provided by this invention, by setting multiple armor layers and setting a protective layer between adjacent armor layers, can effectively improve the overall structural strength and mechanical strength of the cable, prevent defects such as creases and damage during use, and at the same time, the protective layer can absorb impact well and thus protect the armor layer. Moreover, the thermally conductive and flame-retardant material in the protective layer can conduct the heat generated during the use of the cable in a timely manner, avoiding heat accumulation.

[0008] Optionally, the preparation method of the thermally conductive flame retardant includes: surface activation of a carbon matrix in a silane solution to obtain an activated matrix; ultrasonic mixing of the activated matrix in an aluminum ion solution containing a surfactant to obtain a mixed suspension; adding an alkaline solution dropwise to the mixed suspension and reacting it with ultrasound to obtain a modified intermediate; and modifying the surface of the modified intermediate with melamine to obtain the thermally conductive flame retardant.

[0009] Optionally, the silane solute in the silane solution includes KH550, KH792, or KH602.

[0010] Optionally, the mass ratio of silane solute to carbon matrix in the silane solution is (0.3-0.5):1.

[0011] Optionally, the carbon matrix includes single-walled carbon nanotubes or multi-walled carbon nanotubes.

[0012] Optionally, the carbon matrix is ​​surface activated in a silane solution at 40°C-50°C.

[0013] Optionally, the carbon matrix is ​​mechanically mixed in a silane solution for surface activation, the mechanical mixing including mechanical stirring, ultrasonication, or oscillation.

[0014] Optionally, the surfactant includes KH550, KH792 or KH602.

[0015] Optionally, the mass ratio of aluminum ions to the activated matrix in the aluminum ion solution is (0.5-0.8):1.

[0016] Optionally, the mass ratio of the surfactant to the activated matrix is ​​(0.01-0.03):1.

[0017] Optionally, the activated substrate can be preheated at 40°C-60°C.

[0018] Optionally, the activated matrix is ​​mixed in an aluminum ion solution containing a surfactant at an ultrasonic frequency of 10 kHz to 30 kHz.

[0019] Optionally, the alkaline solute in the alkaline solution includes sodium hydroxide or potassium hydroxide.

[0020] Optionally, the alkaline solution is added dropwise to the mixed suspension at a rate of 30 drops / min to 50 drops / min.

[0021] Optionally, the alkaline solution is added dropwise to a mixed suspension at 50°C-60°C and subjected to ultrasonic reaction.

[0022] Optionally, the modified intermediate is stirred and mixed in a melamine solution, then allowed to stand for separation and dried to obtain a thermally conductive flame retardant.

[0023] Optionally, the mass ratio of the modified intermediate to the melamine solute in the melamine solution is 1:(0.1-0.3).

[0024] Optionally, the solvent for the melamine solution may include dimethylformamide.

[0025] Optionally, the modified intermediate is stirred and mixed in a melamine solution at 40℃-50℃.

[0026] Optionally, the protective layer comprises, by weight percentage: 8%-12% thermally conductive flame retardant, 5%-8% functional additives, and the balance being an elastomer.

[0027] Optionally, the elastomer includes a styrene elastomer or a polyolefin elastomer.

[0028] Optionally, the functional additives include antioxidants, lubricants, and plasticizers.

[0029] Optionally, the antioxidant is antioxidant 1010.

[0030] Optionally, the lubricant is a stearate.

[0031] Optionally, the plasticizer is one of dioctyl phthalate and dibutyl phthalate.

[0032] Optionally, the styrene elastomer is one of SBS and SEBS.

[0033] Optionally, the cable sheath includes a polyvinyl chloride body and a thermally conductive and flame-retardant body, wherein the mass fraction of the thermally conductive and flame-retardant body is 10%-25%.

[0034] Secondly, the present invention also provides a method for preparing a moisture-proof and explosion-proof cable, comprising: winding multiple conductive cores in the same direction and simultaneously braiding an insulating shielding layer to obtain a core; extruding a filling layer on the outside of the core to obtain a primary wire; sequentially covering the primary wire with an armor layer and a protective layer to obtain a secondary wire; and hot-melt extruding a cable sheath on the outside of the secondary wire to obtain a moisture-proof and explosion-proof cable.

[0035] The moisture-proof and explosion-proof cable provided by this invention has at least one of the following beneficial technical effects compared with the prior art:

[0036] 1. The protective layer can not only fill the gap between adjacent armor layers, but also effectively buffer when subjected to external impact. At the same time, the thermally conductive and flame-retardant material in the protective layer can form a thermally conductive frame, which can not only connect the armor layers on both sides, but also effectively improve the compressive strength of the protective layer, thereby improving the buffering performance of the protective layer.

[0037] 2. Multiple armor layers are sleeved on the outside of the filling isolation layer, and a protective layer is filled between adjacent armor layers. Therefore, a concentric structure of armor layer-protective layer-armor layer is formed on the outside of the battery cell, which can play a good protective role for the internal battery cell when the moisture-proof and explosion-proof cable is impacted.

[0038] 3. The thermally conductive and flame-retardant material can quickly dissipate heat from inside the cable when there is a large temperature difference between the inside and outside of the cable, thus preventing the cable from overheating. When a fire occurs outside the cable, the sodium hydroxide on the thermally conductive and flame-retardant material decomposes rapidly, thereby playing a flame-retardant role. Attached Figure Description

[0039] Figure 1 A cross-sectional structural diagram of a moisture-proof and explosion-proof cable provided by the present invention;

[0040] Figure 2 A flowchart illustrating a method for preparing a thermally conductive flame-retardant body provided by the present invention;

[0041] Figure 3 A flowchart illustrating a method for preparing a moisture-proof and explosion-proof cable provided by the present invention.

[0042] Explanation of reference numerals in the attached figures:

[0043] 1. Cable core; 2. Insulation and shielding layer; 3. Filler layer; 4. Armor layer; 5. Protective layer; 6. Cable sheath. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0045] See Figure 1This invention provides a moisture-proof and explosion-proof cable, comprising a cable core formed by winding multiple conductive cores in the same direction, with an insulating shield layer covering the outside of the cable core, and a filler layer formed outside the insulating shield layer. In fact, by winding multiple conductive cores in the same direction, the cable's flexibility can be effectively enhanced, while reducing its resistance and improving the stability and efficiency of current transmission. The insulating shield layer can isolate the cable core to prevent current leakage and avoid leakage current. Furthermore, the filler layer can fill the gaps in the cable's linear structure and improve its compactness, while also providing a certain buffering effect.

[0046] Specifically, see Figure 1 Multiple armor layers are sleeved outside the filling and isolation layer, and a protective layer is filled between adjacent armor layers. Therefore, a concentric structure of armor layer-protective layer-armor layer is formed on the outside of the battery core. This can play a good protective role for the internal battery core when the moisture-proof and explosion-proof cable is impacted. The armor layer can effectively enhance the structural strength. In addition, the armor layer can be made of metal materials, which can not only withstand greater stress, but also ensure that the cable will not easily break or deform when subjected to tensile or bending stress. At the same time, the metal armor layer can form electrostatic shielding and electromagnetic shielding.

[0047] Furthermore, the protective layer not only fills the gaps between adjacent armor layers but also effectively cushions impacts. Simultaneously, the thermally conductive and flame-retardant material within the protective layer forms a thermally conductive framework, connecting the armor layers on both sides and effectively improving the protective layer's pressure resistance, thereby enhancing its cushioning performance. Additionally, the thermally conductive and flame-retardant material rapidly dissipates heat from within the cable when there is a significant temperature difference between the inside and outside, preventing overheating. Furthermore, in the event of a fire outside the cable, the sodium hydroxide on the thermally conductive and flame-retardant material rapidly decomposes, thus providing flame retardancy.

[0048] In fact, see Figure 1 The cable sheath is fitted on the outermost armor layer, and the cable sheath can protect the overall structure of the cable from the corrosion of external environmental factors. At the same time, as the first line of defense against moisture, the cable sheath can effectively prevent moisture from penetrating, reduce the diffusion coefficient of water molecules in the cable sheath, and work together with the armor layer inside to improve the overall structural stability and impact resistance of the cable.

[0049] Specifically, the protective layer contains a thermally conductive flame retardant, which is a carbon matrix doped with aluminum hydroxide nanoparticles. In practice, when the thermally conductive flame retardant is dispersed within the protective layer and cured, it forms a thermally conductive framework that supports the layer. This not only improves the structural strength of the protective layer but also promotes heat transfer between layers. Furthermore, it works in conjunction with the metallic armor layer to maintain the stability of the cable's internal and external temperatures.

[0050] Furthermore, when heat is transferred within the thermally conductive framework constructed by the thermally conductive flame retardant material, when the heat reaches the decomposition temperature of aluminum hydroxide, the aluminum hydroxide decomposes, absorbs a large amount of heat, and decomposes to produce water, thereby reducing the heat and thus improving the flame retardancy of the protective layer and improving the durability of the cable in high-temperature environments.

[0051] In some embodiments, see Figure 2 The preparation method of the thermally conductive flame retardant body includes the following steps:

[0052] S1. An activated matrix is ​​prepared by surface activation of a carbon matrix in a silane solution;

[0053] S2. The activated matrix is ​​ultrasonically mixed in an aluminum ion solution containing a surfactant to obtain a mixed suspension;

[0054] S3. The alkaline solution was added dropwise to the mixed suspension and reacted by sonication to obtain the modified intermediate.

[0055] S4. A thermally conductive flame retardant body is prepared by modifying the surface of the modified intermediate with melamine.

[0056] In fact, when the carbon matrix is ​​surface activated in a silane solution in step S1, not only can the number of active functional groups introduced on the carbon matrix surface be increased to increase the number of surface active sites, but also the aggregation and sedimentation of the carbon matrix during dispersion can be avoided. In addition, by selecting different silane solutions, heterogeneous element doping can be carried out on the carbon matrix surface, which is beneficial to promoting the cohesion of aluminum ions.

[0057] Specifically, the silane solute in the silane solution used in step S1 includes KH550, KH792, or KH602. Meanwhile, the solvent in the silane solution can be a commonly used organic solvent in the art, necessary to dissolve the silane solute; for example, anhydrous ethanol, NMP, DMF, etc., can be used. Furthermore, in step S1, to improve the surface treatment rate of the carbon matrix by the silane solute, and considering production costs, the mass ratio of silane solute to carbon matrix can be controlled at (0.3-0.5):1.

[0058] In some embodiments, the carbon matrix used in step S1 includes single-walled carbon nanotubes or multi-walled carbon nanotubes. In fact, both single-walled and multi-walled carbon nanotubes possess high thermal conductivity because their atomic structure features tightly linked carbon atoms through covalent bonds, forming efficient heat conduction channels. Simultaneously, carbon nanotubes can act as inorganic fillers, filling the gaps in the protective layer to improve structural strength. Furthermore, their large specific surface area provides ample active sites for the in-situ generation of aluminum hydroxide particles, allowing the aluminum hydroxide nanoparticles to adhere uniformly to the surface of the carbon nanotubes. This also facilitates melamine modification, enabling the melamine-modified layer to coat the aluminum hydroxide nanoparticles, thereby improving the positional stability of the aluminum hydroxide nanoparticles.

[0059] In some embodiments, the carbon matrix is ​​surface-activated in a silane solution at 40°C-50°C in step S1. In fact, surface activation at 40°C-50°C promotes contact between the silane solute in the silane solution and the carbon matrix, and facilitates the hydrolysis of the silane solute, thereby introducing active groups onto the carbon matrix surface. Furthermore, when reacting the carbon matrix in the silane solution, mechanical mixing can effectively accelerate the reaction rate; specifically, mechanical mixing includes mechanical stirring, ultrasonication, or oscillation.

[0060] In fact, when the activated matrix is ​​ultrasonically mixed with the aluminum ion solution containing the surfactant in step S2, the activated matrix can be uniformly dispersed in the aluminum ion solution under the action of ultrasound. At the same time, the surfactant can further reduce the surface tension of the activated matrix. In addition, the active groups on the surface of the activated matrix can interact with the aluminum ions, thereby making the aluminum ions uniformly attached to the surface of the activated matrix.

[0061] In some embodiments, the surfactant in the aluminum ion solution during step S2 includes KH550, KH792, or KH602. In fact, using the same silane surfactant in the aluminum ion solution as in step S1 for surface activation promotes uniform dispersion of the activated matrix within the aluminum ion solution, thereby improving the uniformity of surface bonding of aluminum ions.

[0062] In some embodiments, during step S2, the mass ratio of aluminum ions to the activated matrix in the aluminum ion solution is (0.5-0.8):1. In practice, using aluminum ions within this range allows for sufficient bonding with the active sites on the activated matrix surface. If the aluminum ion content is too low, the uniformity of the aluminum hydroxide generated on the activated matrix surface will be reduced, thereby decreasing the flame retardant performance. Conversely, if the aluminum ion content is too high, excessively large aluminum hydroxide agglomerates will be generated, affecting the dispersion of the thermally conductive flame retardant within the protective layer.

[0063] In some embodiments, during step S2, the mass ratio of surfactant to activated matrix in the aluminum ion solution is (0.01-0.03):1. Furthermore, the activated matrix can be preheated at 40°C-60°C, which helps to improve its activity and promotes the bonding of aluminum ions on the surface of the activated matrix. Simultaneously, the activated matrix can be mixed in the surfactant-containing aluminum ion solution at an ultrasonic frequency of 10kHz-30kHz, thus utilizing the ultrasonic cavitation effect to further prevent the activated matrix from agglomerating.

[0064] In fact, in step S3, the alkaline solution is added to the mixed suspension to react with the aluminum ions attached to the surface of the activated substrate to generate aluminum hydroxide precipitate, which then adheres in situ to the surface of the activated substrate to form an aluminum hydroxide nanolayer. Furthermore, the reaction under ultrasonic conditions promotes the uniform growth of aluminum hydroxide nanoparticles on the surface of the activated substrate, resulting in better adhesion of the aluminum hydroxide nanoparticles to the activated substrate surface.

[0065] In fact, by uniformly dispersing the activated matrix and aluminum ions in step S2 before adding the alkaline solution in step S3, aluminum ions are always in excess during the reaction, which is conducive to the formation of aluminum hydroxide precipitate. If the activated matrix and alkaline solution are dispersed in advance before adding the aluminum ion solution, aluminate is easily formed.

[0066] In some embodiments, the alkaline solute in the alkaline solution used in step S3 includes sodium hydroxide or potassium hydroxide, while the aluminum ion solution used in step S2 can be an aluminum chloride solution. Thus, when the alkaline solution reacts with the aluminum ion solution, aluminum hydroxide nanoparticles and potassium chloride or sodium chloride can be generated. Furthermore, when adding the alkaline solution in step S3, it is added dropwise to the mixed suspension at a rate of 30 drops / min to 50 drops / min, which helps to improve the uniformity of the aluminum hydroxide nanoparticles on the activated substrate surface.

[0067] In some embodiments, during step S3, the mixed suspension can be preheated in a water bath at 50°C-60°C before the alkaline solution is added dropwise to the mixed suspension for ultrasonic reaction. In fact, preheating the mixed suspension improves the activity of the activated matrix and enhances the binding stability between aluminum ions and the activated matrix. Therefore, ultrasonic treatment after adding the alkaline solution removes bubbles from the surface of the activated matrix and promotes the in-situ formation of aluminum hydroxide nanoparticles.

[0068] In fact, in step S4, modifying the surface of the modified intermediate with melamine not only coats and protects the aluminum hydroxide nanoparticles on the surface to prevent them from detaching, but also organically modifies the surface of the modified intermediate, thereby effectively improving the compatibility of the thermally conductive flame retardant within the protective layer. Furthermore, melamine itself is rich in nitrogen, which decomposes at high temperatures to produce non-combustible gases such as nitrogen, further enhancing the flame-retardant properties of the thermally conductive flame retardant.

[0069] In some embodiments, during step S4, the modified intermediate is stirred and mixed in a melamine solution, then allowed to stand for separation and dried to obtain a thermally conductive flame retardant. In practice, during the preparation of the modified intermediate in step S3, the surfactant in the aluminum ion solution can surface-activate the modified intermediate, thereby facilitating the surface coating treatment of the modified intermediate with melamine in the melamine solution.

[0070] In some embodiments, during step S4, the mass ratio of the modified intermediate to the melamine solute in the melamine solution is 1:(0.1-0.3). In fact, by adjusting the amount of melamine solute, the thickness of the coating layer formed by melamine on the surface of the modified intermediate can be adjusted. This avoids excessively thick melamine layers affecting the flame-retardant properties of the aluminum hydroxide nanoparticles on the surface of the modified intermediate, and also avoids insufficient melamine leading to a thin or uneven coating, which could cause the aluminum hydroxide particles to easily detach.

[0071] In some embodiments, the solvent in the melamine solution used in step S4 includes dimethylformamide (DMF). DMF is indeed a polar aprotic solvent with extremely strong dissolving power, capable of completely dissolving melamine and forming a stable, homogeneous solution. Furthermore, the solvent in the melamine solution can be a commonly used organic solvent in the art, as long as it can completely dissolve the melamine. Specifically, in step S4, the modified intermediate can be stirred and mixed in a melamine solution at 40°C-50°C. This promotes uniform coating of melamine on the surface of the modified intermediate and improves coating efficiency.

[0072] In practice, the protective layer comprises, by mass percentage: 8%-12% thermally conductive flame retardant, 5%-8% functional additives, and the remainder being elastomer. Specifically, this content of thermally conductive flame retardant, when uniformly dispersed within the protective layer, can construct a stable thermally conductive network, thereby providing support to the protective layer and connecting the armor layers on both sides. However, if the content of the thermally conductive flame retardant is too high, it not only increases production costs but also makes it prone to precipitation within the protective layer, thus affecting its structural strength.

[0073] In fact, functional additives in the protective layer can help enhance its overall performance. Specifically, functional additives include antioxidants, lubricants, and plasticizers. Antioxidants can prevent the protective layer from being oxidized during long-term use, thus effectively enhancing the overall service life of the cable. Lubricants can reduce friction during the preparation of the protective layer, which not only promotes the uniform distribution of thermally conductive and flame-retardant materials within the protective layer but also improves processing performance.

[0074] Specifically, the elastomer used as the main component in the protective layer serves as structural support and protection. It not only endows the protective layer with good elasticity and flexibility, allowing it to deform appropriately when subjected to external forces such as compression and tension, but also effectively absorbs the impact, thus providing excellent protection for the armor layer. In fact, the elastomer includes styrene elastomers or polyolefin elastomers, with styrene elastomers specifically being one of SBS or SEBS.

[0075] In some embodiments, the cable sheath is made of polyvinyl chloride (PVC) material, specifically comprising a PVC matrix and a thermally conductive and flame-retardant matrix, with the thermally conductive and flame-retardant matrix comprising 10%-25% by mass. In practice, the cable sheath can use commonly used PVC formulations in the art, and additionally, functional additives such as lubricants, plasticizers, antioxidants, and UV absorbers can be added to improve the overall performance of the cable sheath. Specifically, by adding a thermally conductive and flame-retardant matrix to the cable sheath, the thermal conductivity and flame-retardant properties of the cable sheath can be improved, thereby enhancing the cable's moisture-proof and explosion-proof performance.

[0076] See Figure 3 The present invention also provides a method for preparing a moisture-proof and explosion-proof cable, comprising the following steps:

[0077] Z1. A wire core is obtained by winding multiple conductive cores in the same direction and simultaneously weaving an insulating shielding layer.

[0078] Z2. A primary wire is obtained by extruding a filler layer on the outside of the core;

[0079] Z3. After covering the outer side of the primary wire with an armor layer and a protective layer in sequence, the intermediate wire is obtained.

[0080] Z4. A moisture-proof and explosion-proof cable is made by hot-melt extrusion molding a cable sheath on the outside of the intermediate wire.

[0081] Preparation Example 1

[0082] Example 1 provides a method for preparing a thermally conductive flame retardant, including the following steps:

[0083] S1. After stirring and mixing single-walled carbon nanotubes in an ethanol solution containing KH550 (the mass ratio of single-walled carbon nanotubes to KH550 is 1:0.2), the mixture is ultrasonically treated at a frequency of 10kHz for 10 minutes in a water bath at 45℃, stirred at a speed of 100rpm for 20 minutes and then separated into solid and liquid. After rinsing the precipitate with deionized water, the precipitate is dried to constant weight in a vacuum drying oven at 60℃ to obtain the activated matrix.

[0084] S2. Dissolve KH550 in an aluminum chloride aqueous solution (the mass ratio of KH550, aluminum ions and activated matrix is ​​0.02:0.6:1). Then, quickly transfer the activated matrix, which has been dried and preheated in a vacuum drying oven, into the aluminum chloride aqueous solution. After ultrasonic treatment at a frequency of 20kHz for 15 minutes in a water bath at 60℃, a mixed suspension is obtained.

[0085] S3. Add a saturated aqueous solution of sodium hydroxide dropwise at a rate of 40 drops / min to the mixed suspension in a water bath at 60°C, and sonicate at 20kHz to promote a complete reaction. Control the total amount of sodium hydroxide added to the molar ratio of aluminum chloride to 3:1. After the addition is complete, stir at 200rpm for 30min. After solid-liquid separation and rinsing the precipitate with deionized water, dry it in a vacuum drying oven at 50°C to constant weight to obtain the modified intermediate.

[0086] S4. After removing the modified intermediate from the drying oven, quickly add it to a melamine solution (the mass ratio of the modified intermediate to melamine is 1:0.2, and the solvent is dimethylformamide) kept at 50℃ in a water bath. Stir at 200 rpm for 30 min and let it stand for 2 h to react. After solid-liquid separation, dry it to constant weight in a vacuum drying oven at 50℃ to obtain a thermally conductive flame retardant.

[0087] Preparation Example 2

[0088] Example 2 provides a method for preparing a thermally conductive flame retardant, including the following steps:

[0089] D1. After stirring and mixing single-walled carbon nanotubes in an ethanol solution containing KH550 (the mass ratio of single-walled carbon nanotubes to KH550 is 1:0.2), the mixture is ultrasonically treated at a frequency of 10kHz for 10 minutes in a water bath at 45℃, stirred at a speed of 100rpm for 20 minutes, and then separated into solid and liquid phases. After rinsing the precipitate with deionized water, the precipitate is dried to constant weight in a vacuum drying oven at 60℃ to obtain the activated matrix.

[0090] D2. Dissolve KH550 in an aqueous solution of aluminum chloride (mass ratio of KH550, aluminum ions and activated matrix is ​​0.02:0.6:1). Then quickly transfer the activated matrix, which has been dried and preheated in a vacuum drying oven, into the aqueous solution of aluminum chloride. After ultrasonic treatment at a frequency of 20kHz for 15 minutes in a water bath at 60℃, a mixed suspension is obtained.

[0091] D3. Add a saturated aqueous solution of sodium hydroxide dropwise to the mixed suspension in a water bath at 60°C at a rate of 40 drops / min, and sonicate at 20kHz to promote a full reaction. Control the total amount of sodium hydroxide added to the molar ratio of aluminum chloride to 3:1. After the addition is complete, stir at 200rpm for 30min. After solid-liquid separation and rinsing the precipitate with deionized water, dry it in a vacuum drying oven at 50°C to constant weight to obtain a thermally conductive flame retardant.

[0092] Preparation Example 3

[0093] Example 3 of this preparation provides a method for preparing a thermally conductive flame retardant, including the following steps:

[0094] D1. After stirring and mixing single-walled carbon nanotubes in an ethanol solution containing KH550 (the mass ratio of single-walled carbon nanotubes to KH550 is 1:0.2), the mixture is ultrasonically treated at a frequency of 10kHz for 10 minutes in a water bath at 45℃, stirred at a speed of 100rpm for 20 minutes, and then separated into solid and liquid phases. After rinsing the precipitate with deionized water, the precipitate is dried to constant weight in a vacuum drying oven at 60℃ to obtain the activated matrix.

[0095] D2. After removing the activated matrix from the drying oven, quickly add it to a melamine solution (the mass ratio of activated matrix to melamine is 1:0.2, and the solvent is dimethylformamide) kept at 50℃ in a water bath. Stir at 200 rpm for 30 min and let it stand for 2 h. After solid-liquid separation, dry it in a vacuum drying oven at 50℃ to constant weight to obtain a thermally conductive flame retardant.

[0096] Example 1

[0097] This embodiment 1 provides a method for preparing a protective layer, comprising: mixing 82 parts of styrene elastomer SEBS, 20 parts of polypropylene, 10 parts of the thermally conductive and flame-retardant body prepared in Preparation Example 1, 1 part of antioxidant, 5 parts of plasticizer TOTM, and 2 parts of stabilizer calcium stearate, and then extruding the mixture to obtain the protective layer.

[0098] Example 2

[0099] This embodiment 2 provides a method for preparing a protective layer, comprising: mixing 62 parts of styrene elastomer SEBS, 20 parts of polypropylene, 10 parts of the thermally conductive and flame-retardant body prepared in Preparation Example 2, 1 part of antioxidant, 5 parts of plasticizer TOTM, and 2 parts of stabilizer calcium stearate, and then extruding the mixture to obtain the protective layer.

[0100] Comparative Example 1

[0101] Comparative Example 1 provides a method for preparing a protective layer, comprising: mixing 82 parts of styrene elastomer SEBS, 20 parts of polypropylene, 10 parts of the thermally conductive flame retardant prepared in Preparation Example 3, 1 part of antioxidant, 5 parts of plasticizer TOTM, and 2 parts of stabilizer calcium stearate, and then extruding the mixture to obtain the protective layer.

[0102] Comparative Example 2

[0103] Comparative Example 2 provides a method for preparing a protective layer, comprising: mixing 82 parts of styrene elastomer SEBS, 20 parts of polypropylene, 10 parts of aluminum hydroxide powder, 1 part of antioxidant, 5 parts of plasticizer TOTM, and 2 parts of stabilizer calcium stearate, and then extruding the mixture to obtain the protective layer.

[0104] Performance testing

[0105] The protective layers obtained in Examples 1 and 2, and Comparative Examples 1 and 2, were tested for the following items: Mechanical properties (tensile strength and elongation at break) of the protective layers were tested according to the methods described in Part 11 of GB / T2951-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Fibers," and the results are shown in Table 1 below; Mechanical properties (tensile strength and elongation at break) of the protective layers were tested according to the methods described in Part 12 of GB / T2951-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Fibers," and the changes in tensile strength and elongation were recorded, and the results are shown in Table 2 below; The volume resistivity of the protective layers at 20°C was tested according to the standard described in GB / T 1410-2006, and the results are shown in Table 3 below; The protective layers were immersed in deionized water at 80°C for 240 hours, the surface moisture was wiped off, and the volume resistivity at 20°C was retested, and the results are shown in Table 3 below; Based on ASTM... The method described in D2863 for measuring the oxygen index yields the results shown in Table 4 below.

[0106] A primary wire is formed by wrapping the outer side of the core with high-molecular-weight polyethylene as the filler layer, and a 0.8mm thick steel strip is used as the armor layer. In Example 1, the protective layer is 4mm thick and located between the two armor layers. The cable sheath material, by weight, includes 5 parts of thermally conductive and flame-retardant material, 100 parts of polyvinyl chloride resin, 40 parts of plasticizer TOTM, 9 parts of plasticizer DOP, 0.5 parts of antioxidant 1010, 0.3 parts of ultraviolet absorber UV5411, and 0.5 parts of paraffin wax. When a tensile force of 80 times the cable diameter is applied to the moisture-proof and explosion-proof cable at 25°C and stabilized for 120 seconds, no displacement of the armor layer is detected, indicating that the moisture-proof and explosion-proof cable provided by this invention has good explosion-proof performance. As can be seen from Tables 1 to 4, the thermally conductive and flame-retardant material provided by this invention, after being added to the protective layer, can significantly improve the heat aging resistance and flame-retardant performance of the protective layer.

[0107] Table 1 Mechanical properties of the protective layers of Examples 1 to 2 and Comparative Examples 1 to 2

[0108]

[0109] Table 2 Thermal aging performance of the protective layers in Examples 1 to 2 and Comparative Examples 1 to 2

[0110]

[0111] Table 3. Water resistance performance of the protective layers in Examples 1 to 2 and Comparative Examples 1 to 2

[0112]

[0113] Table 4 Oxygen Index of Protective Layers in Examples 1 to 2 and Comparative Examples 1 to 2

[0114]

[0115] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the invention as set forth in the claims. Furthermore, the invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A moisture-proof and explosion-proof cable, characterized in that, The cable core comprises multiple conductive cores wound in the same direction. An insulating shielding layer is fitted around the outside of the cable core, and a filling layer is formed outside the insulating shielding layer. Multiple armor layers are disposed outside the filling layer, with a protective layer filling between the multiple armor layers. The outermost armor layer is fitted with a cable sheath. The protective layer contains a thermally conductive flame retardant, which is a carbon matrix doped with aluminum hydroxide nanoparticles. The preparation method of the thermally conductive flame retardant includes: surface activation of the carbon matrix in a silane solution to obtain an activated matrix; ultrasonic mixing of the activated matrix in an aluminum ion solution containing a surfactant to obtain a mixed suspension; dropwise addition of an alkaline solution to the mixed suspension followed by ultrasonic reaction and separation to obtain a modified intermediate; and melamine modification of the surface of the modified intermediate to obtain the thermally conductive flame retardant.

2. The moisture-proof and explosion-proof cable according to claim 1, characterized in that, The silane solute in the silane solution includes KH550, KH792, or KH602; and / or, the mass ratio of the silane solute to the carbon matrix in the silane solution is (0.3-0.5):1; and / or, the carbon matrix includes single-walled carbon nanotubes or multi-walled carbon nanotubes; and / or, the carbon matrix is ​​surface activated in a silane solution at 40℃-50℃; and / or, the carbon matrix is ​​mechanically mixed in a silane solution to perform surface activation, wherein the mechanical mixing includes mechanical stirring, ultrasound, or oscillation.

3. The moisture-proof and explosion-proof cable according to claim 1, characterized in that, The surfactant includes KH550, KH792 or KH602; and / or, the mass ratio of aluminum ions to the activated matrix in the aluminum ion solution is (0.5-0.8):1; and / or, the mass ratio of the surfactant to the activated matrix is ​​(0.01-0.03):1; and / or, the activated matrix is ​​preheated at 40℃-60℃; and / or, the activated matrix is ​​mixed in an aluminum ion solution containing the surfactant at an ultrasonic frequency of 10kHz-30kHz.

4. The moisture-proof and explosion-proof cable according to claim 1, characterized in that, The alkaline solute in the alkaline solution includes sodium hydroxide or potassium hydroxide; and / or, the alkaline solution is added dropwise to the mixed suspension at a rate of 30 drops / min to 50 drops / min; and / or, the alkaline solution is added dropwise to the mixed suspension at 50°C to 60°C for ultrasonic reaction.

5. The moisture-proof and explosion-proof cable according to claim 1, characterized in that, The modified intermediate is stirred and mixed in a melamine solution, then allowed to stand for separation and dried to obtain a thermally conductive flame retardant; wherein the mass ratio of the modified intermediate to the melamine solute in the melamine solution is 1:(0.1-0.3); and / or, the solvent of the melamine solution includes dimethylformamide; and / or, the modified intermediate is stirred and mixed in a melamine solution at 40℃-50℃.

6. The moisture-proof and explosion-proof cable according to claim 1, characterized in that, The protective layer comprises, by weight percentage: 8%-12% thermally conductive flame retardant, 5%-8% functional additives, and the balance being an elastomer; the elastomer includes styrene elastomer or polyolefin elastomer; the functional additives include antioxidants, lubricants, and plasticizers.

7. The moisture-proof and explosion-proof cable according to claim 6, characterized in that, The antioxidant is antioxidant 1010; and / or the lubricant is stearate; and / or the plasticizer includes one of dioctyl phthalate and dibutyl phthalate; and / or the styrene elastomer is one of SBS and SEBS.

8. The moisture-proof and explosion-proof cable according to claim 1, characterized in that, The cable sheath comprises a polyvinyl chloride body and a thermally conductive and flame-retardant body, wherein the mass fraction of the thermally conductive and flame-retardant body is 10%-25%.

9. A method for preparing a moisture-proof and explosion-proof cable as described in any one of claims 1 to 8, characterized in that, include: The conductor core is made by winding multiple conductive cores in the same direction and simultaneously braiding an insulating shielding layer; a primary wire is made by extruding a filling layer on the outside of the conductor core; an intermediate wire is made by sequentially covering the primary wire with an armor layer and a protective layer; and a moisture-proof and explosion-proof cable is made by hot-melt extrusion forming a cable sheath on the outside of the intermediate wire.

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