Moistureproof and explosion-proof cable and preparation method thereof

Abstract

The invention provides a moisture-proof and explosion-proof cable and a preparation method thereof, and relates to the technical field of cables. The moisture-proof and explosion-proof cable provided by the invention comprises a cable core formed by winding a plurality of strands of conductive cores in the same direction, an insulation shielding layer sleeves the outer side of the cable core, and a filling layer is formed on the outer side of the insulation shielding layer; a plurality of armor layers are arranged on the outer side of the filling isolation layer, a protective layer is filled among the plurality of armor layers, and the outermost armor layer is sleeved with a cable sheath; wherein the protective layer is internally provided with a heat-conducting flame-retardant body, and the heat-conducting flame-retardant body is a carbon matrix of which the surface is doped with aluminum hydroxide nanoparticles. The moisture-proof and explosion-proof performance of the cable can be improved.

Description

Technical Field

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

[0002] In many industrial fields such as petrochemicals, coal mining, and natural gas transportation, the production environment is extremely complex, and there are a large number of flammable and explosive gases, which pose a serious threat to the safety and stability of power transmission cables. For example, when power transmission cables are in a humid environment for a long time, the moisture in the environment penetrates into the cable sheath and easily causes discharge, which causes the explosion of the gas in the environment and leads to production accidents. Therefore, moisture-proof and explosion-proof cables have become important equipment to ensure the safe and orderly progress of production activities. They not only maintain the normal operation of various electrical equipment, but also are an important line of defense to ensure the safety of personnel and the integrity of production facilities. If the performance of moisture-proof and explosion-proof cables is insufficient, the losses caused are difficult to estimate.

[0003] The currently commonly used moisture-proof and explosion-proof cables are composed of a metal conductor, an insulating layer, a moisture-proof layer and an explosion-proof armor layer from the inside to the outside. The metal conductor is used to conduct current as the core channel for current transmission, while the insulation layer insulates the metal conductor to prevent leakage of the metal conductor. The moisture-proof layer and the explosion-proof armor layer protect the insulation layer to prevent leakage of the moisture-proof and explosion-proof cable due to rupture of the insulation layer. In addition, the moisture-proof layer and the explosion-proof armor layer play a moisture-proof and explosion-proof role respectively. The armor layer can improve the structural strength of the moisture-proof and explosion-proof cable by virtue of its metal structure.

[0004] However, although moisture-proof and explosion-proof cables improve their moisture-proof performance by providing a moisture-proof layer, when the cables are used in a high humidity environment for a long time, moisture can easily penetrate into the surface, especially when the cables are subjected to external pressure or because of defects such as creases and damage on the surface during installation. Moisture penetration is particularly likely to occur, resulting in a decrease in insulation performance and affecting the morphological integrity of the armor layer inside the cable, thereby causing arc discharge during the use of the cable and increasing the risk of explosion. Therefore, there is an urgent need to provide a solution to improve the above problems. Summary of the invention

[0005] The object of the present invention is to provide a moisture-proof and explosion-proof cable and a preparation method thereof.

[0006] In a first aspect, the present invention provides a moisture-proof and explosion-proof cable, comprising a cable core formed by winding a plurality of conductive cores in the same direction, wherein an insulating shielding layer is sheathed on the outside of the cable core, and a filling layer is formed on the outside of the insulating shielding layer; a plurality of armor layers are arranged on the outside of the filling isolation layer, a protective layer is filled between the plurality of armor layers, and the armor layer located on the outermost layer is sheathed with a cable sheath; wherein the protective layer comprises a heat-conductive and flame-retardant body, and the heat-conductive and flame-retardant body is a carbon matrix with aluminum hydroxide nanoparticles doped on the surface.

[0007] The moisture-proof and explosion-proof cable provided by the present invention can effectively improve the overall structural strength and mechanical strength of the cable by arranging multiple armor layers and arranging a protective layer between adjacent armor layers, thereby preventing the cable from having defects such as creases and breakages during use. At the same time, the protective layer can absorb impact well and thus protect the armor layer. Moreover, the heat-conducting and flame-retardant body in the protective layer can promptly conduct the heat generated during the use of the cable to avoid heat accumulation.

[0008] Optionally, the preparation method of the thermally conductive flame retardant comprises: surface activating a carbon matrix in a silane solution to obtain an activated matrix; ultrasonically mixing the activated matrix in an aluminum ion solution containing a surfactant to obtain a mixed suspension; dropwise adding an alkaline solution into the mixed suspension to perform an ultrasonic reaction and separate the modified intermediate; and performing melamine modification on the surface of the modified intermediate 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 the silane solute in the silane solution to the carbon matrix 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 substrate is surface activated in a silane solution at 40° C.-50° C.

[0013] Optionally, the carbon substrate is mechanically mixed in the silane solution for surface activation, wherein the mechanical mixing includes mechanical stirring, ultrasound or shaking.

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

[0015] Optionally, the mass ratio of aluminum ions in the aluminum ion solution to the activated matrix 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 is preheated at 40°C-60°C.

[0018] Alternatively, 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-50 drops / min.

[0021] Optionally, the alkaline solution is added dropwise into the mixed suspension at 50° C.-60° C. for 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 heat-conductive flame-retardant body.

[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 of the melamine solution includes dimethylformamide.

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

[0026] Optionally, the protective layer comprises, by mass percentage, 8%-12% of a thermally conductive flame retardant, 5%-8% of a functional additive, and the remainder of an elastomer.

[0027] Optionally, the elastomer comprises 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 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 comprises a polyvinyl chloride body and a heat-conductive flame-retardant body, and the mass fraction of the heat-conductive flame-retardant body is 10%-25%.

[0034] In a second aspect, 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 synchronously weaving an insulating shielding layer to obtain a wire core; extruding a filling layer on the outside of the wire core to obtain a primary wire; sequentially covering an armor layer and a protective layer on the outside of the primary wire to obtain an intermediate wire; and hot-melt extruding a cable sheath on the outside of the intermediate wire to obtain a moisture-proof and explosion-proof cable.

[0035] Compared with the prior art, the moisture-proof and explosion-proof cable provided by the present invention has at least one of the following beneficial technical effects: 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 heat-conducting and flame-retardant body in the protective layer can form a heat-conducting 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; 2. Multiple armor layers are sleeved on the outside of the filling isolation layer, and a protective layer is filled between adjacent armor layers, so that a concentric structure of armor layer-protective layer-armor layer is formed on the outside of the battery core, which can provide good protection for the internal battery core when the moisture-proof and explosion-proof cable is impacted; 3. When there is a large temperature difference between the inside and outside of the cable, the thermally conductive flame retardant can quickly dissipate the heat inside the cable to prevent the cable from overheating. When a fire occurs outside the cable, the sodium hydroxide on the thermally conductive flame retardant will quickly decompose and play a flame retardant role. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of the cross-sectional structure of a moisture-proof and explosion-proof cable provided by the present invention; Figure 2 A flow chart of a method for preparing a heat-conducting flame-retardant body provided by the present invention; Figure 3 The present invention provides a flow chart of a method for preparing a moisture-proof and explosion-proof cable.

[0037] Description of reference numerals: 1. Cable core; 2. Insulation shielding layer; 3. Filling layer; 4. Armor layer; 5. Protective layer; 6. Cable sheath. DETAILED DESCRIPTION

[0038] In order to make the purpose, 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 part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with general skills in the field to which the present invention belongs.

[0039] See also Figure 1The present invention provides a moisture-proof and explosion-proof cable, including a cable core formed by winding a plurality of conductive cores in the same direction, and 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. In fact, by winding a plurality of conductive cores in the same direction, the flexibility of the cable can be effectively enhanced, while reducing the resistance of the cable and improving the stability and efficiency of current transmission, and the insulating shielding layer can isolate the cable core to prevent current leakage and avoid leakage. In addition, the filling layer can fill the linear gaps of the cable and improve the compactness of its structure, while having a certain buffering effect.

[0040] Specifically, see Figure 1 A plurality of armor layers are sleeved on the outside of the filling isolation layer, and a protective layer is filled between adjacent armor layers, so that a concentric structure of armor layer-protective layer-armor layer is formed on the outside of the battery core, which can provide good protection 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 material, 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.

[0041] In addition, 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 flame retardant 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. In addition, the thermally conductive flame retardant can quickly dissipate the heat inside the cable when there is a large difference in temperature between the inside and outside of the cable to prevent the cable from overheating. When a fire occurs outside the cable, the sodium hydroxide on the thermally conductive flame retardant quickly decomposes to play a flame retardant role.

[0042] In fact, see Figure 1 A cable sheath is provided on the surface of the outermost armor layer, and the cable sheath can protect the overall structure of the cable from erosion by external environmental factors. At the same time, the cable sheath, as the first line of defense against moisture in the cable, can effectively prevent moisture from penetrating, reduce the diffusion coefficient of water molecules in the cable sheath, and cooperate with the armor layer inside to improve the overall structural stability and impact resistance of the cable.

[0043] Specifically, the protective layer contains a heat-conducting flame retardant, and the heat-conducting flame retardant is a carbon matrix doped with aluminum hydroxide nanoparticles on the surface. In fact, when the heat-conducting flame retardant is dispersed in the protective layer and solidified, the heat-conducting flame retardant in the protective layer can form a heat-conducting skeleton and support it in the protective layer, which can not only improve the structural strength of the protective layer, but also promote heat transfer between the protective layers, and cooperate with the metal armor layer to achieve the stability of the temperature inside and outside the cable.

[0044] In addition, when heat is transferred within the thermally conductive skeleton constructed by the thermally conductive flame retardant, when the heat reaches the decomposition temperature of aluminum hydroxide, aluminum hydroxide decomposes to absorb a large amount of heat and decomposes to produce water, thereby reducing heat, which is beneficial to improve the flame retardancy of the protective layer and thus improve the durability of the cable in high temperature environments.

[0045] In some embodiments, see Figure 2 The preparation method of the thermally conductive flame retardant body comprises the following steps: S1, preparing an activated matrix by surface activation of the carbon matrix in a silane solution; S2, ultrasonically mixing the activated matrix in an aluminum ion solution containing a surfactant to obtain a mixed suspension; S3, adding the alkaline solution dropwise into the mixed suspension, performing ultrasonic reaction, and separating the modified intermediate; S4. A thermally conductive flame retardant is prepared by modifying the surface of the modified intermediate with melamine.

[0046] In fact, when the carbon matrix is ​​surface activated in the silane solution in step S1, not only can active functional groups be introduced into the surface of the carbon matrix to increase the number of surface active sites, but also the agglomeration and sedimentation of the carbon matrix during the dispersion process can be avoided. In addition, by selecting different silane solutions, the surface of the carbon matrix can be doped with impurities, which is beneficial to promote the combination of aluminum ions.

[0047] Specifically, the silane solute in the silane solution used in step S1 includes KH550, KH792 or KH602. At the same time, the solvent in the silane solution can be selected from organic solvents commonly used in the art, so that the silane solute can be dissolved as necessary, for example, anhydrous ethanol, NMP, DMF, etc. can be used. In addition, in step S1, in order to increase the surface treatment rate of the silane solute on the carbon substrate and comprehensively consider the production cost, the mass ratio of the silane solute to the carbon substrate can be controlled to (0.3-0.5):1.

[0048] 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 carbon nanotubes and multi-walled carbon nanotubes have high thermal conductivity, because the carbon atoms in their atomic structure are closely connected by covalent bonds to form an efficient heat conduction channel, and the carbon nanotubes can be used as inorganic fillers to fill the gaps in the protective layer to improve the structural strength, and because of their large specific surface area, they can provide sufficient active sites for the in-situ generation of aluminum hydroxide particles, so that aluminum hydroxide nanoparticles can be evenly attached to the surface of the carbon nanotubes, and at the same time, it is conducive to melamine modification, so that the melamine modified layer covers the aluminum hydroxide nanoparticles, thereby improving the positional stability of the aluminum hydroxide nanoparticles.

[0049] In some embodiments, in step S1, the carbon matrix is ​​surface activated in a silane solution at 40°C-50°C. In fact, surface activation at 40°C-50°C can promote the contact between the silane solute in the silane solution and the carbon matrix, and promote the hydrolysis of the silane solute to introduce active groups on the surface of the carbon matrix. In addition, when the carbon matrix is ​​reacted in the silane solution, mechanical mixing can effectively promote the reaction rate, and specifically mechanical mixing includes mechanical stirring, ultrasound or oscillation.

[0050] In fact, when the activated matrix is ​​ultrasonically mixed with the aluminum ion solution containing a surfactant in step S2, the activated matrix can be evenly dispersed in the aluminum ion solution under the action of ultrasound, and the surfactant can further reduce the surface tension of the surface 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 evenly attached to the surface of the activated matrix.

[0051] In some embodiments, when performing step S2, the surfactant in the aluminum ion solution includes KH550, KH792 or KH602. In fact, by using the same silane active agent as that used in the surface activation in step S1 in the aluminum ion solution, it is beneficial to promote the uniform dispersion of the activated matrix in the aluminum ion solution, which is beneficial to improve the surface bonding uniformity of the aluminum ions.

[0052] In some embodiments, when performing step S2, the mass ratio of aluminum ions in the aluminum ion solution to the activated matrix is ​​(0.5-0.8): 1. In fact, the use of aluminum ions within this ratio range can fully bond with the active sites on the surface of the activated matrix. If the aluminum ion content is too low, the uniformity of aluminum hydroxide generated on the surface of the activated matrix will be reduced, thereby reducing the flame retardant performance. When the aluminum ion content is too high, excessively large aluminum hydroxide agglomerates will be generated, thereby affecting the dispersibility of the thermally conductive flame retardant in the protective layer.

[0053] In some embodiments, when performing step S2, the mass ratio of the surfactant to the activated matrix in the aluminum ion solution is (0.01-0.03): 1. In addition, the activated matrix can be preheated at 40°C-60°C in advance, which is conducive to improving the activity of the activated matrix and promoting the bonding of aluminum ions on the surface of the activated matrix. At the same time, the activated matrix can be mixed in the aluminum ion solution containing the surfactant at an ultrasonic frequency of 10kHz-30kHz, so that the ultrasonic cavitation effect can be used to further avoid the agglomeration of the activated matrix.

[0054] In fact, in step S3, an alkaline solution is added to the mixed suspension to react with aluminum ions attached to the surface of the activated matrix to generate aluminum hydroxide precipitates, which are attached to the surface of the activated matrix in situ to form an aluminum hydroxide nanolayer. In addition, when reacting under an ultrasonic environment, aluminum hydroxide nanoparticles can be promoted to grow uniformly on the surface of the activated matrix, and aluminum hydroxide nanoparticles can be better attached to the surface of the activated matrix.

[0055] In fact, by pre-dispersing the activated matrix and aluminum ions uniformly in step S2 and then adding the alkaline solution in step S3, the aluminum ions are always in excess during the reaction, which is conducive to the formation of aluminum hydroxide precipitation. If the activated matrix and the alkaline solution are dispersed in advance and then the aluminum ion solution is added, it is easy to generate metaaluminate.

[0056] In some embodiments, when performing step S3, the alkaline solute in the alkaline solution used includes sodium hydroxide or potassium hydroxide, and the aluminum ion solution used in step S2 can be an aluminum chloride solution, so that aluminum hydroxide nanoparticles and potassium chloride or sodium chloride can be generated when the alkaline solution reacts with the aluminum ion solution. In addition, when adding the alkaline solution in step S3, the alkaline solution is added dropwise to the mixed suspension at a rate of 30 drops / min-50 drops / min, which is conducive to improving the uniformity of the aluminum hydroxide nanoparticles on the surface of the activated substrate.

[0057] In some embodiments, when executing step S3, the mixed suspension may be preheated in a water bath environment at 50°C-60°C, and then the alkaline solution may be added dropwise into the mixed suspension for ultrasonic reaction. In fact, preheating the mixed suspension is beneficial to improving the activity of the activated matrix in the mixed suspension, improving the binding stability between aluminum ions and the activated matrix, and then ultrasonic treatment after the addition of the alkaline solution can remove bubbles on the surface of the activated matrix and promote the in-situ generation of aluminum hydroxide nanoparticles.

[0058] In fact, in step S4, melamine is modified on the surface of the modified intermediate, which can not only coat and protect the aluminum hydroxide nanoparticles on the surface to prevent the aluminum hydroxide nanoparticles from falling off, but also organically modify the surface of the modified intermediate, thereby effectively improving the compatibility of the thermal conductive flame retardant in the protective layer. In addition, melamine itself is rich in nitrogen elements, which can decompose at high temperatures to produce non-flammable gases such as nitrogen, thereby further enhancing the flame retardant properties of the thermal conductive flame retardant.

[0059] In some embodiments, when performing step S4, the modified intermediate is stirred and mixed in the melamine solution, then allowed to stand for separation and dried to obtain a heat-conductive flame retardant. In fact, when the modified intermediate is prepared in step S3, the surfactant in the aluminum ion solution can activate the surface of the modified intermediate, thereby facilitating the surface coating of the modified intermediate with melamine in the melamine solution.

[0060] In some embodiments, when performing 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 to avoid the melamine thickness being too thick and affecting the flame retardant performance of the aluminum hydroxide nanoparticles on the surface of the modified intermediate, and to avoid the aluminum hydroxide particles falling off easily due to too little melamine, which leads to too thin thickness or difficulty in uniform coverage.

[0061] In some embodiments, the solvent in the melamine solution used when performing step S4 includes dimethylformamide. In fact, dimethylformamide (DMF) is a polar aprotic solvent with extremely strong dissolving ability, which can completely dissolve melamine and form a morphologically stable and uniform solution. In addition, the solvent in the melamine solution can be selected from organic solvents commonly used in the art, and it is necessary to be able to completely dissolve melamine. Specifically, when performing step S4, the modified intermediate can be stirred and mixed in a melamine solution at 40°C-50°C, which can promote the uniform coating of melamine on the surface of the modified intermediate and improve the coating efficiency.

[0062] In fact, the protective layer includes, by mass percentage, 8%-12% thermally conductive flame retardant, 5%-8% functional additives and the remainder of elastomer. Specifically, after the thermally conductive flame retardant of this content is evenly dispersed in the protective layer, a stable thermal conductive network can be constructed, thereby supporting the protective layer and connecting the armor layers on both sides. In fact, when the content of the thermally conductive flame retardant is too high, it will not only increase the production cost, but also easily precipitate in the protective layer, thereby affecting the structural strength of the protective layer.

[0063] In fact, the functional additives in the protective layer can help enhance the comprehensive performance of the protective layer. Specifically, the functional additives include antioxidants, lubricants, and plasticizers. Antioxidants can prevent the performance degradation caused by oxidation of the protective layer during long-term use, thereby effectively enhancing the overall service life of the cable, while lubricants can reduce friction when preparing the protective layer, which can not only promote the uniform distribution of the thermal conductive flame retardant in the protective layer, but also improve the processing performance.

[0064] Specifically, the elastomer used in the protective layer as a main component can play a role in structural support and protection. It can not only give the protective layer good elasticity and flexibility, but also make the protective layer deform accordingly when the cable is subjected to mechanical effects such as external compression and stretching, thereby effectively absorbing the impact, and thus playing a good protective role for the armor layer. In fact, the elastomer includes styrene elastomer or polyolefin elastomer, and the styrene elastomer is one of SBS and SEBS.

[0065] In some embodiments, the cable sheath is made of polyvinyl chloride material, specifically including a polyvinyl chloride body and a thermally conductive flame retardant, and the mass fraction of the thermally conductive flame retardant is 10%-25%. In fact, the cable sheath can adopt the polyvinyl chloride formula commonly used in the art, and functional additives such as lubricants, plasticizers, antioxidants, and ultraviolet absorbers can also be added thereto to improve the comprehensive performance of the cable sheath. Specifically, by adding a thermally conductive flame retardant to the cable sheath, the thermally conductive flame retardant performance of the cable sheath can be improved, thereby improving the moisture-proof and explosion-proof performance of the cable.

[0066] See also Figure 3 The present invention also provides a method for preparing a moisture-proof and explosion-proof cable, comprising the following steps: Z1, winding multiple conductive cores in the same direction and synchronously weaving insulating shielding layers to obtain a wire core; Z2, extruding a filling layer outside the wire core to obtain a primary wire; Z3, after the outer side of the primary wire is covered with an armor layer and a protective layer in sequence, an intermediate wire is obtained; Z4. A moisture-proof and explosion-proof cable is produced by hot-melt extruding a cable sheath on the outside of the intermediate wire.

[0067] Preparation Example 1 This preparation example 1 provides a method for preparing a thermally conductive flame retardant body, comprising the following steps: S1. After stirring and mixing the single-walled carbon nanotubes in an ethanol solution containing KH550 (the mass ratio of the single-walled carbon nanotubes to KH550 is 1:0.2), ultrasonic treatment was performed at a frequency of 10 kHz for 10 min in a water bath environment at 45°C, and then the mixture was stirred at a speed of 100 rpm for 20 min and solid-liquid separation was performed. After the precipitate was washed with deionized water, it was dried in a vacuum drying oven at 60°C to constant weight to obtain an activated matrix; S2, stirring and dissolving KH550 in an aqueous solution of aluminum chloride (the mass ratio of KH550, aluminum ions and activated matrix is ​​0.02:0.6:1), and then quickly transferring the activated matrix dried and preheated in a vacuum drying oven to the aqueous solution of aluminum chloride, and ultrasonically treating it at a frequency of 20 kHz for 15 minutes in a water bath environment at 60°C to obtain a mixed suspension; S3, adding a saturated aqueous solution of sodium hydroxide dropwise at a rate of 40 drops / min into the mixed suspension in a water bath environment at 60°C, and subjecting it to ultrasonic treatment at 20kHz to promote sufficient reaction, and controlling the molar ratio of the total amount of sodium hydroxide added to aluminum chloride to be 3:1; after the dropwise addition is completed, stirring is maintained at a speed of 200rpm for 30min, solid-liquid separation is performed, and the precipitate is rinsed with deionized water, and then dried in a vacuum drying oven at 50°C to constant weight to obtain a modified intermediate; S4. After taking out the modified intermediate from the drying oven, quickly add it into a melamine solution (the mass ratio of the modified intermediate to melamine is 1:0.2, and the solvent is dimethylformamide) kept warm in a 50°C water bath environment, stir at 200 rpm for 30 minutes, let it stand for 2 hours to react, separate the solid and liquid, and dry it in a 50°C vacuum drying oven to constant weight to obtain a thermally conductive flame retardant.

[0068] Preparation Example 2 This preparation example 2 provides a method for preparing a thermally conductive flame retardant body, comprising the following steps: D1. After stirring and mixing the single-walled carbon nanotubes in an ethanol solution containing KH550 (the mass ratio of the single-walled carbon nanotubes to KH550 is 1:0.2), ultrasonic treatment was performed at a frequency of 10 kHz for 10 min in a water bath environment at 45°C, and then stirred at a speed of 100 rpm for 20 min to separate the solid and liquid. After washing the precipitate with deionized water, it was dried in a vacuum drying oven at 60°C to constant weight to obtain an activated matrix; D2, KH550 was stirred and dissolved in an aqueous solution of aluminum chloride (the mass ratio of KH550, aluminum ions and activated matrix was 0.02:0.6:1), and then the activated matrix dried and preheated in a vacuum drying oven was quickly transferred to the aqueous solution of aluminum chloride, and ultrasonically treated at a frequency of 20 kHz for 15 minutes in a water bath environment at 60°C to obtain a mixed suspension; D3. A saturated aqueous solution of sodium hydroxide was added dropwise at a rate of 40 drops / min into the mixed suspension in a water bath at 60°C, and ultrasonic treatment was performed at 20kHz to promote sufficient reaction, and the molar ratio of the total amount of sodium hydroxide added to aluminum chloride was controlled to be 3:1; after the addition was completed, stirring was maintained at 200rpm for 30min, the solid-liquid separation was performed, the precipitate was rinsed with deionized water, and then dried in a vacuum drying oven at 50°C to constant weight to obtain a thermally conductive flame retardant.

[0069] Preparation Example 3 This preparation example 3 provides a method for preparing a thermally conductive flame retardant body, comprising the following steps: D1. After stirring and mixing the single-walled carbon nanotubes in an ethanol solution containing KH550 (the mass ratio of the single-walled carbon nanotubes to KH550 is 1:0.2), ultrasonic treatment was performed at a frequency of 10 kHz for 10 min in a water bath environment at 45°C, and then stirred at a speed of 100 rpm for 20 min to separate the solid and liquid. After washing the precipitate with deionized water, it was dried in a vacuum drying oven at 60°C to constant weight to obtain an activated matrix; D2. After taking the activated substrate out of the drying oven, quickly add the melamine solution (the mass ratio of the activated substrate to melamine is 1:0.2, and the solvent is dimethylformamide) kept warm in a 50°C water bath environment, stir at 200 rpm for 30 minutes, let it stand for 2 hours to react, separate the solid and liquid, and dry it in a 50°C vacuum drying oven to constant weight to obtain a thermally conductive flame retardant.

[0070] Example 1

[0071] This 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 thermal conductive flame retardant prepared in Preparation Example 1, 1 part of an antioxidant, 5 parts of a plasticizer TOTM, and 2 parts of a stabilizer calcium stearate, and then extruding and molding the mixture to prepare a protective layer.

[0072] Example 2

[0073] This Example 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 thermal conductive flame retardant prepared in Preparation Example 2, 1 part of an antioxidant, 5 parts of a plasticizer TOTM, and 2 parts of a stabilizer calcium stearate, and then extruding and molding the mixture to obtain a protective layer.

[0074] Comparative Example 1 This 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 thermal conductive flame retardant prepared in Preparation Example 3, 1 part of an antioxidant, 5 parts of a plasticizer TOTM, and 2 parts of a stabilizer calcium stearate, and then extruding and molding the mixture to prepare a protective layer.

[0075] Comparative Example 2 This 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 and molding to obtain a protective layer.

[0076] Performance Testing The protective layers prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were tested for the following items: Based on the method described in Part 11 of GB / T2951-2008 "General Test Methods for Insulation and Sheath Materials of Electric Cables and Optical Cables", the protective layer was tested for mechanical properties (tensile strength and elongation at break), and the results are shown in Table 1 below; Based on the method described in Part 12 of GB / T2951-2008 "General Test Methods for Insulation and Sheath Materials of Electric Cables and Optical Cables", the protective layer was subjected to heat aging treatment at 158°C for 168h, and then subjected to mechanical property testing, and the change rate of tensile strength and the change rate of elongation were recorded, and the results are shown in Table 2 below; Based on the standard described in GB / T 1410-2006, the volume resistivity of the protective layer at 20°C was tested, and the results are shown in Table 3 below; After the protective layer was immersed in deionized water at 80°C for 240h, 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 oxygen index was measured by the method described in D2863, and the results are shown in Table 4 below.

[0077] A high molecular weight polyethylene is used as a filling layer to coat the outside of the wire core to form a primary wire, and a steel strip with a thickness of 0.8 mm is used as an armor layer. The thickness of the protective layer in Example 1 is 4 mm and is located between the two armor layers. The material of the cable sheath includes 5 parts of thermally conductive flame retardant, 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. At 25°C, a tensile force of 80 times the cable diameter is applied to the moisture-proof and explosion-proof cable, and after stabilization for 120s, it is detected that the armor layer has not shifted, which indicates that the moisture-proof and explosion-proof cable provided by the present invention has good explosion-proof performance. It can be seen from Tables 1 to 4 that the thermally conductive flame retardant provided by the present invention can significantly improve the heat aging resistance and flame retardant properties of the protective layer after adding the protective layer.

[0078] Table 1 Mechanical properties of protective layers of Examples 1 to 2 and Comparative Examples 1 to 2

[0079] Table 2 Thermal aging properties of protective layers of Examples 1 to 2 and Comparative Examples 1 to 2

[0080] Table 3 Water resistance of the protective layer of Example 1 to Example 2 and Comparative Example 1 to Comparative Example 2

[0081] Table 4 Oxygen index of protective layer of Example 1 to Example 2 and Comparative Example 1 to Comparative Example 2

[0082] Although the embodiments of the present invention are described in detail above, it is obvious 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 are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.

Claims

1. A moisture-proof and explosion-proof cable, characterized in that: It comprises a cable core formed by winding a plurality of conductive cores in the same direction, wherein an insulating shielding layer is sheathed on the outside of the cable core, and a filling layer is formed on the outside of the insulating shielding layer; a plurality of armor layers are arranged on the outside of the filling isolation layer, a protective layer is filled between the plurality of armor layers, and a cable sheath is sheathed on the outermost armor layer; wherein the protective layer comprises a heat-conducting flame-retardant body, and the heat-conducting flame-retardant body is a carbon matrix with aluminum hydroxide nanoparticles doped on the surface.

2. The moisture-proof and explosion-proof cable according to claim 1, characterized in that: The preparation method of the thermal conductive flame retardant comprises: performing surface activation on a carbon matrix in a silane solution to obtain an activated matrix; performing ultrasonic mixing on the activated matrix in an aluminum ion solution containing a surfactant to obtain a mixed suspension; adding an alkali solution dropwise into the mixed suspension to perform ultrasonic reaction and then separating to obtain a modified intermediate; and performing melamine modification on the surface of the modified intermediate to obtain the thermal conductive flame retardant.

3. The moisture-proof and explosion-proof cable according to claim 2, characterized in that: The silane solute in the silane solution includes KH550, KH792 or KH602; and / or, the mass ratio of the silane solute in the silane solution to the carbon matrix 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°C-50°C; and / or, the carbon matrix is ​​mechanically mixed in the silane solution for surface activation, and the mechanical mixing includes mechanical stirring, ultrasound or oscillation.

4. The moisture-proof and explosion-proof cable according to claim 2, characterized in that: The surfactant includes KH550, KH792 or KH602; and / or, the mass ratio of aluminum ions in the aluminum ion solution to the activated matrix 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°C-60°C in advance; and / or, the activated matrix is ​​mixed in the aluminum ion solution containing the surfactant at an ultrasonic frequency of 10kHz-30kHz.

5. The moisture-proof and explosion-proof cable according to claim 2, 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-50 drops / min; and / or, the alkaline solution is added dropwise to the mixed suspension at 50° C.-60° C. for ultrasonic reaction.

6. The moisture-proof and explosion-proof cable according to claim 2, 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°C-50°C.

7. The moisture-proof and explosion-proof cable according to claim 1, characterized in that: The protective layer comprises, by mass percentage, 8%-12% of a thermally conductive flame retardant, 5%-8% of a functional additive and the remainder of an elastomer; the elastomer comprises a styrene elastomer or a polyolefin elastomer; the functional additive comprises an antioxidant, a lubricant and a plasticizer.

8. The moisture-proof and explosion-proof cable according to claim 7, 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.

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

10. A method for preparing a moisture-proof and explosion-proof cable according to any one of claims 1 to 9, characterized in that: include: The wire core is obtained by winding multiple conductive cores in the same direction and braiding the insulating shielding layer synchronously; the primary wire is obtained by extruding the filling layer on the outside of the wire core; the intermediate wire is obtained by sequentially covering the armor layer and the protective layer on the outside of the primary wire; the moisture-proof and explosion-proof cable is obtained by hot-melt extruding the cable sheath on the outside of the intermediate wire.

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