Intelligent early warning cable and preparation method thereof

Abstract

The invention discloses an intelligent early warning cable and a preparation method of the intelligent early warning cable, and belongs to the technical field of cables. The flame-retardant polyolefin composite material is prepared from the following raw materials in parts by weight: 5 to 10 parts of ethylene-vinyl acetate copolymer, 10 to 20 parts of linear low-density polyethylene, 10 to 15 parts of ethylene-octylene copolymer, 3 to 8 parts of compatilizer, 15 to 20 parts of organic modified vanadium dioxide, 30 to 40 parts of ionic liquid modified aluminum hydroxide, 1 to 1.5 parts of cross-linking agent and 1 to 2 parts of lubricant. Organic modified vanadium dioxide is introduced into a sheath layer material to serve as an intelligent early warning material, the cable sheath layer is endowed with the temperature change characteristic, when the local temperature of the cable is abnormally increased due to overload and other reasons, the material can trigger color change, and therefore a striking visual mark is formed in a complex wire harness, and the early warning effect is improved. And the problems of lag, low efficiency and existence of blind areas of the traditional monitoring means are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of cables, and particularly relates to an intelligent early-warning cable and a preparation method thereof. BACKGROUND

[0002] A cable is usually composed of a core, an insulation layer and a protective layer, has the characteristics of simple structure, convenient use and safety and reliability, and is suitable for power transmission under various environmental conditions indoors and outdoors.

[0003] Cables are widely used in end power distribution environments such as homes, office buildings, shopping malls and factory workshops. Some scene hazards often exist in these scenarios: (1) Randomly increasing loads: users privately connect high-power equipment, causing the cable to run in overload for a long time. (2) Aging of connection points: The contact resistance of connection parts such as sockets, wiring terminals and piercing clamps increases due to oxidation and loosening, which can also cause local overheating when passing through normal current. (3) Harmonic current: Modern power electronic devices (such as frequency converters, LED lights and computers) generate harmonics, causing the neutral line of the cable to overload or even overheat. The above problems can all cause the local temperature of the cable to abnormally rise, but since the action of the circuit breaker needs to meet both the current intensity and the time condition, such overheating may not immediately trigger a protection trip.

[0004] For the problem of abnormal rise in the local temperature of a cable, there is currently a lack of effective means for rapid positioning and troubleshooting. For example: A power distribution cabinet or bridge is usually densely packed with dozens or even hundreds of cables. When the system alarms or fails, it is difficult for the operation and maintenance personnel to quickly determine which cable and which section has overheated from the complex and intricate wiring. The traditional method is to use an infrared thermometer to scan point by point, which is inefficient and cannot capture transient overheating or hidden overheating points. In addition, cables are usually laid in cable trenches, bridges, shafts and ceilings, which are often blind areas or areas with delayed response for active fire protection systems such as smoke detectors and temperature detectors. When these detectors alarm, the fire may have occurred or spread.

[0005] In summary, the fault risk of a cable has concealment, universality and serious consequences, and the traditional monitoring means often has a lag, therefore, it is a technical problem to be solved to provide a cable with intelligent early-warning function. SUMMARY

[0006] One of the purposes of the present application is to provide an intelligent early-warning cable to solve the problem that the local temperature of a cable abnormally rises but is difficult to quickly locate and troubleshoot in the prior art.

[0007] The second purpose of the present application is to provide a preparation method of the above-mentioned intelligent early-warning cable.

[0008] The purpose of the present application can be achieved by the following technical solutions: An intelligent early warning cable comprises a conductor core, an insulation layer and a sheath layer from inside to outside, wherein the sheath layer is made of a flame-retardant polyolefin composite material comprising the following raw materials in parts by weight: ethylene-vinyl acetate copolymer 5-10 parts, linear low density polyethylene 10-20 parts, ethylene-octene copolymer 10-15 parts, compatibilizer 3-8 parts, organic modified vanadium dioxide 15-20 parts, ionic liquid modified aluminum hydroxide 30-40 parts, crosslinking agent 1-1.5 parts, and lubricant 1-2 parts.

[0009] Further, the preparation steps of the flame-retardant polyolefin composite material are as follows: The ethylene-vinyl acetate copolymer, linear low density polyethylene, ethylene-octene copolymer, compatibilizer, organic modified vanadium dioxide, ionic liquid modified aluminum hydroxide, crosslinking agent and lubricant are placed together in an internal mixer at a temperature of 130-150°C and a rotation speed of 40-50 rpm, and mixed for 10-15 min, and then transferred to a twin-screw extruder for extrusion granulation at 120-160°C to obtain the flame-retardant polyolefin composite material.

[0010] Further, the raw materials for preparing the organic modified vanadium dioxide include amino vanadium dioxide, tris(3-aminophenyl)phosphine oxide and p-phenylene diisothiocyanate, and the mass ratio of the amino vanadium dioxide, tris(3-aminophenyl)phosphine oxide and p-phenylene diisothiocyanate is 3.8-4.5:12.1:7.2.

[0011] Further, the tris(3-aminophenyl)phosphine oxide is an existing substance, and can be prepared by referring to the literature "Synthesis of tris(3-aminophenyl)phosphine oxide" by Hu Manen.

[0012] Further, the preparation steps of the organic modified vanadium dioxide are as follows: The amino vanadium dioxide, tris(3-aminophenyl)phosphine oxide, p-phenylene diisothiocyanate and N,N-dimethylformamide are added to a reaction kettle, stirred at room temperature for 8-10 h, and after the reaction is completed, the filter cake is washed with N,N-dimethylformamide and deionized water in sequence, and finally dried to obtain the organic modified vanadium dioxide.

[0013] Further, the raw materials for preparing the amino vanadium dioxide include nano vanadium dioxide and amino siloxane, and the mass ratio of the nano vanadium dioxide and the amino siloxane is 1-2:1, and the amino siloxane is N-(2-aminoethyl)-3-aminopropyl trimethoxysilane and / or 3-aminopropyl triethoxysilane.

[0014] Further, the preparation steps of the amino vanadium dioxide are as follows: The nanometer vanadium dioxide, ethanol solution and aminosiloxane are added into a reaction kettle, and the temperature is increased to 70-80 DEG C and reacted for 6-12 h, and after cooling, filtration and drying, aminated vanadium dioxide is obtained, wherein the mass fraction of the ethanol solution is 75-90%.

[0015] As a thermochromic material, vanadium dioxide has a metal-insulator transition at a phase transition temperature of 68 DEG C, and the color reversibly changes with temperature, which is transparent or light in color below the phase transition temperature, and the color deepens above the phase transition temperature. By using its thermochromic properties, it can be added to the cable sheath material to effectively respond to the presence of abnormal heating of the cable. However, vanadium dioxide is sensitive to oxygen and water in the environment, resulting in insufficient thermochromic stability. To this end, the present application first couples it with aminosiloxane to obtain aminated vanadium dioxide, and then in the presence of tris (3-aminophenyl) phosphine oxide and p-phenylenediisothiocyanate, it is modified with isothiocyanate and amino groups (forming thiourea bond) by in-situ polymerization to prepare nitrogen-containing phosphorus-sulfur hyperbranched polymer modified vanadium dioxide. On the one hand, based on the isolation effect of the organic modification layer and the hydrophobic effect of the benzene ring of the hyperbranched polymer and the antioxidant effect of the thiourea structure, the contact between oxygen and water in the environment and vanadium dioxide is reduced, and the thermochromic stability is improved. On the other hand, by modifying treatment, the dispersibility of vanadium dioxide in polyolefin base material is improved, and the adverse effects caused by agglomeration and other phenomena are reduced. In addition, the modification means of the present application also forms an organic modification layer carrying silicon, nitrogen, phosphorus and sulfur flame retardant elements on vanadium dioxide, which is beneficial to strengthening the flame retardant performance of the sheath layer.

[0016] Further, the raw materials for preparing the ionic liquid modified aluminum hydroxide include hexafluorophosphate ionic liquid and aluminum hydroxide, and the mass ratio of hexafluorophosphate ionic liquid to aluminum hydroxide is 2-3:7-8.

[0017] Further, the average particle size of the aluminum hydroxide is 2-10 μm.

[0018] Further, the hexafluorophosphate ionic liquid is at least one of 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-octyl-3-methylimidazolium hexafluorophosphate and 1-tetradecyl-3-methylimidazolium hexafluorophosphate.

[0019] Further, the preparation steps of the ionic liquid modified aluminum hydroxide are as follows: The hexafluorophosphate ionic liquid is added with petroleum ether in an amount of 5-10 times the volume, stirred uniformly, and then aluminum hydroxide is added. Under room temperature, ultrasonic treatment is carried out for 0.5-2 h, and finally filtration is carried out. The filter cake is dried in an oven at 80-100 DEG C for 24 h to obtain ionic liquid modified aluminum hydroxide.

[0020] In view of the problem of poor compatibility with the matrix of aluminum hydroxide as a polyolefin flame retardant, the present application modifies and treats the aluminum hydroxide by using hexafluorophosphate ionic liquid, forms a coating layer on the surface of the aluminum hydroxide through electrostatic adsorption and hydrogen bonding, and improves the dispersibility of the aluminum hydroxide and the compatibility between the aluminum hydroxide and the matrix.

[0021] Further, the compatibilizer is maleic anhydride grafted POE.

[0022] Further, the crosslinking agent is at least one of triallyl cyanurate, triallyl isocyanurate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate and pentaerythritol tetraacrylate.

[0023] Further, the lubricant is at least one of magnesium stearate, stearic acid and polyethylene wax.

[0024] The preparation method of the intelligent early warning cable comprises the following steps: S1, a polyvinyl chloride material is coated on the surface of the conductor core to form an insulating layer by using an extrusion process, and an insulating core is obtained; S2, a halogen-free flame-retardant polyolefin composite material is coated on the surface of the insulating core by using an extrusion process, and then irradiation crosslinking is performed to form a sheath layer, and an intelligent early warning cable is obtained.

[0025] Further, the conductor core is obtained by twisting copper wires, and the copper wires are tin-plated copper wires or silver-plated copper wires.

[0026] Further, the insulating layer is made of a polyvinyl chloride material and has a thickness of 0.3-0.7mm.

[0027] Further, the sheath layer has a thickness of 0.5-0.8mm.

[0028] Further, in the preparation method, the insulating layer and the sheath layer are obtained by a conventional extrusion process in the art, and the specific process parameters are limited according to the requirements of the insulating layer, the sheath layer material and the cable, and excessive limitation is not made here.

[0029] Further, the irradiation crosslinking dose is 80-240kGy, and the irradiation source is a high-energy electron beam or a cobalt source.

[0030] The present application has the following advantages: 1.The present application provides a kind of intelligent early warning cable, introduce organic modified vanadium dioxide as intelligent early warning material in sheath layer material, give cable sheath layer temperature change characteristics, when the local temperature of cable is abnormally increased due to overload and other reasons, the material will trigger color change, thereby forming a conspicuous visual mark in complex wiring, which enables operation and maintenance personnel to identify and locate the heat hazard being formed before current tripping or disaster occurs, only by naked eye, the fault handling is improved from passive response to active intervention, solve the problems of traditional monitoring means lag, low efficiency and blind area.

[0031] 2.For the problem that vanadium dioxide is sensitive to oxygen and water in the environment, leading to insufficient thermal discoloration stability, the present application uses amino vanadium dioxide, tris (3-aminophenyl) phosphine oxide and p-phenylenediisothiocyanate as raw materials to prepare nitrogen-containing phosphorus sulfur hyperbranched polymer modified vanadium dioxide. On the one hand, based on the isolation effect of organic modification layer and the hydrophobic effect of hyperbranched polymer benzene ring and the antioxidant effect of thiourea structure, the contact between oxygen and water in the environment and vanadium dioxide is reduced, and the thermal discoloration stability is improved. On the other hand, through modification treatment, the dispersibility of vanadium dioxide in polyolefin base material is improved, and the adverse effects caused by agglomeration and other phenomena are reduced. In addition, the modification means of the present application also forms an organic modification layer carrying silicon, nitrogen, phosphorus and sulfur flame retardant elements on vanadium dioxide, which is beneficial to strengthening the flame retardant performance of the sheath layer.

[0032] 3.The present application uses hexafluorophosphate ionic liquid to modify aluminum hydroxide, which improves the dispersibility of aluminum hydroxide and improves the compatibility between aluminum hydroxide and the matrix, overcoming the problem of poor mechanical properties of polyolefin composite material caused by the introduction of a large amount of inorganic filler. In addition, hexafluorophosphate ionic liquid can promote the formation of dense carbon layer when heated, inhibit the escape of internal combustible and the invasion of external heat and oxygen, and strengthen the flame retardant performance of the sheath layer. The imidazole ring on the surface of ionic liquid modified aluminum hydroxide can produce π-π conjugation interaction with the benzene ring in the hyperbranched polymer layer on the surface of organic modified vanadium dioxide. This strong interfacial interaction constructed by π-π stacking can effectively limit the slippage of polymer molecular chain, and more evenly disperse the load to the entire composite material system under external force, thereby improving the tensile strength of the material. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0034] The ethylene-vinyl acetate copolymer (EVA) in the application has a melt index of 3-8 g / 10 min, a mass fraction of vinyl acetate of 18-33%, and is sourced from ExxonMobil Chemical; the linear low-density polyethylene (LLDPE) has a melt index of 2-10 g / 10 min and is sourced from ExxonMobil Chemical; the polyolefin elastomer has a melt index of 1-5 g / 10 min and is sourced from Beier New Materials; the maleic anhydride grafted POE has a type of MA8510 and a brand of Japan Mitsui; The average particle size of the aluminum hydroxide in the application is 2-10 μm. The tris(3-aminophenyl)phosphine oxide in the application is prepared according to the literature "Synthesis of tris(3-aminophenyl)phosphine oxide".

[0035] The following will be specifically described in combination with examples.

[0036] Preparation Example 1 An organic modified vanadium dioxide is prepared according to the following steps: 3.8 g of aminated vanadium dioxide, 12.1 g of tris(3-aminophenyl)phosphine oxide, 7.2 g of p-phenylene diisothiocyanate, and 250 mL of N,N-dimethylformamide are added into a reaction kettle, and stirred at room temperature for 8 h. After the reaction is completed, the filter cake is washed with N,N-dimethylformamide and deionized water in sequence, and finally dried at 80 ℃ until the weight is constant, to obtain the organic modified vanadium dioxide.

[0037] The aminated vanadium dioxide is prepared according to the following steps: 1 g of nanometer vanadium dioxide, 50 mL of 75 wt% ethanol solution, and 1 g of 3-aminopropyl triethoxysilane are added into a reaction kettle, and heated to 70 ℃ for 6 h. After cooling and filtration, drying is performed to obtain the aminated vanadium dioxide.

[0038] Preparation Example 2 An organic modified vanadium dioxide is prepared according to the following steps: 4.0 g of aminated vanadium dioxide, 12.1 g of tris(3-aminophenyl)phosphine oxide, 7.2 g of p-phenylene diisothiocyanate, and 280 mL of N,N-dimethylformamide are added into a reaction kettle, and stirred at room temperature for 9 h. After the reaction is completed, the filter cake is washed with N,N-dimethylformamide and deionized water in sequence, and finally dried, to obtain the organic modified vanadium dioxide.

[0039] The aminated vanadium dioxide is prepared according to the following steps: 1.5 g of nanometer vanadium dioxide, 80 mL of 80 wt% ethanol solution, and 1 g of N-(2-aminoethyl)-3-aminopropyl trimethoxysilane are added into a reaction kettle, and heated to 75 ℃ for 8 h. After cooling and filtration, drying is performed to obtain the aminated vanadium dioxide.

[0040] Preparation Example 3 An organic modified vanadium dioxide, the preparation steps are as follows: 4.5g of aminated vanadium dioxide, 12.1g of tris(3-aminophenyl)phosphine oxide, 7.2g of p-phenylene diisothiocyanate and 300mL of N,N-dimethylformamide were added to a reaction kettle, stirred at room temperature for 10h, after the reaction was completed, filtration, the filter cake was washed with N,N-dimethylformamide and deionized water in turn, and finally dried to obtain the organic modified vanadium dioxide.

[0041] The preparation steps of the aminated vanadium dioxide are as follows: 2g of nano vanadium dioxide, 100mL of 90wt% ethanol solution and 1g of 3-aminopropyl triethoxysilane were added to a reaction kettle, heated to 80℃ for 12h, cooled and filtered, and then dried to obtain the aminated vanadium dioxide.

[0042] Comparative Example 1 An organic modified vanadium dioxide, compared with Preparation Example 1, p-phenylene diisothiocyanate in Preparation Example 1 was replaced by an equal molar amount of p-phenylene diisocyanate.

[0043] Comparative Example 2 This comparative example is aminated vanadium dioxide, and the preparation process of the aminated vanadium dioxide is the same as that of Preparation Example 2.

[0044] Example 1 An intelligent early warning cable, from inside to outside, includes a conductor core, an insulation layer and a sheath layer, wherein the sheath layer is made of a flame-retardant polyolefin composite material, the flame-retardant polyolefin composite material includes the following raw materials in parts by weight: ethylene-vinyl acetate copolymer 5 parts, linear low density polyethylene 20 parts, ethylene-octene copolymer 15 parts, maleic anhydride grafted POE 3 parts, organic modified vanadium dioxide of Preparation Example 1 15 parts, ionic liquid modified aluminum hydroxide 30 parts, triallyl isocyanurate 1 part, and magnesium stearate 1 part.

[0045] The preparation steps of the flame-retardant polyolefin composite material are as follows: The ethylene-vinyl acetate copolymer, linear low density polyethylene, ethylene-octene copolymer, compatibilizer, organic modified vanadium dioxide, ionic liquid modified aluminum hydroxide, crosslinking agent and lubricant were placed together in an internal mixer, the temperature was 130℃, the rotation speed was 40rpm, and the mixing time was 10min, then they were transferred to a twin-screw extruder for extrusion and granulation to obtain the flame-retardant polyolefin composite material.

[0046] The temperature of the twin-screw was set as follows: zone 1 120℃, zone 2 135℃, zone 3 140℃, zone 4 140℃, zone 5 150℃, zone 6 150℃, zone 7 150℃, and zone 8 140℃.

[0047] The preparation steps of the ionic liquid modified aluminum hydroxide are as follows: 2g of 1-ethyl-3-methylimidazole hexafluorophosphate is added with petroleum ether with a volume of 5 times that of the ionic liquid, and 7g of aluminum hydroxide is added after stirring uniformly. The mixture is ultrasonically treated at room temperature for 0.5h, and finally filtered. The filter cake is dried in an oven at 80°C for 24h to obtain the ionic liquid modified aluminum hydroxide.

[0048] The preparation method of the intelligent early warning cable comprises the following steps: S1, a polyvinyl chloride material is coated on the surface of the conductor core by an extrusion process to form an insulating layer with a thickness of 0.7mm, and an insulating wire core is obtained. The conductor core is obtained by twisting a tinned copper wire. S2, a halogen-free flame-retardant polyolefin composite material is coated on the surface of the insulating wire core by an extrusion process, and then irradiated with high-energy electron beams at 140kGy to form a sheath layer with a thickness of 0.8mm, thereby obtaining the intelligent early warning cable.

[0049] Example 2 An intelligent early warning cable comprises a conductor core, an insulating layer and a sheath layer from inside to outside, wherein the sheath layer is made of a flame-retardant polyolefin composite material, and the flame-retardant polyolefin composite material comprises the following raw materials by weight: ethylene-vinyl acetate copolymer 8 parts, linear low-density polyethylene 16 parts, ethylene-octene copolymer 12 parts, maleic anhydride grafted POE 5 parts, organic modified vanadium dioxide of Preparation Example 1 18 parts, ionic liquid modified aluminum hydroxide 35 parts, triallyl isocyanurate 1.2 parts, and magnesium stearate 1.5 parts.

[0050] The preparation steps of the flame-retardant polyolefin composite material are the same as those in Example 1.

[0051] The preparation steps of the ionic liquid modified aluminum hydroxide are as follows: 2.5g of 1-octyl-3-methylimidazole hexafluorophosphate is added with petroleum ether with a volume of 8 times that of the ionic liquid, and 7.5g of aluminum hydroxide is added after stirring uniformly. The mixture is ultrasonically treated at room temperature for 1h, and finally filtered. The filter cake is dried in an oven at 80°C for 24h to obtain the ionic liquid modified aluminum hydroxide.

[0052] The preparation method of the intelligent early warning cable is the same as that in Example 1.

[0053] Example 3 An intelligent early warning cable comprises a conductor core, an insulating layer and a sheath layer from inside to outside, wherein the sheath layer is made of a flame-retardant polyolefin composite material, and the flame-retardant polyolefin composite material comprises the following raw materials by weight: ethylene-vinyl acetate copolymer 10 parts, linear low-density polyethylene 10 parts, ethylene-octene copolymer 10 parts, maleic anhydride grafted POE 8 parts, organic modified vanadium dioxide of Preparation Example 1 20 parts, ionic liquid modified aluminum hydroxide 40 parts, triallyl isocyanurate 1.5 parts, and magnesium stearate 2 parts.

[0054] The preparation steps of the flame-retardant polyolefin composite are the same as those of Example 1.

[0055] The preparation steps of the ionic liquid modified aluminum hydroxide are as follows: To 3 g of 1-tetradecyl-3-methylimidazolium hexafluorophosphate, 10 times the volume of petroleum ether was added, 8 g of aluminum hydroxide was added after stirring uniformly, ultrasonic treatment was carried out at room temperature for 2 h, and finally filtration was carried out, and the filter cake was dried in an oven at 100 ℃ for 24 h to obtain the ionic liquid modified aluminum hydroxide.

[0056] Example 4 An intelligent early warning cable, compared with Example 1, the difference is only that the organic modified vanadium dioxide in Example 1 is replaced by the product obtained in Preparation Example 2.

[0057] Example 5 An intelligent early warning cable, compared with Example 1, the difference is only that the organic modified vanadium dioxide in Example 1 is replaced by the product obtained in Preparation Example 3.

[0058] Example 6 An intelligent early warning cable, compared with Example 2, the difference is only that the organic modified vanadium dioxide in Example 2 is replaced by the product obtained in Preparation Example 2.

[0059] Example 7 An intelligent early warning cable, compared with Example 2, the difference is only that the organic modified vanadium dioxide in Example 2 is replaced by the product obtained in Preparation Example 3.

[0060] Example 8 An intelligent early warning cable, compared with Example 3, the difference is only that the organic modified vanadium dioxide in Example 3 is replaced by the product obtained in Preparation Example 2.

[0061] Example 9 An intelligent early warning cable, compared with Example 3, the difference is only that the organic modified vanadium dioxide in Example 3 is replaced by the product obtained in Preparation Example 3.

[0062] Comparative Example 1 An intelligent early warning cable, compared with Example 1, the difference is only that the organic modified vanadium dioxide in Example 1 is replaced by the product obtained in Comparative Example 1.

[0063] Comparative Example 2 An intelligent early warning cable, compared with Example 2, the difference is only that the organic modified vanadium dioxide in Example 2 is replaced by the product obtained in Comparative Example 1.

[0064] Comparative Example 3 An intelligent early warning cable, compared with Example 1, the difference is only that the organic modified vanadium dioxide in Example 1 is replaced by the product obtained in Comparative Example 2 in equal mass.

[0065] Comparative Example 4 An intelligent early warning cable, compared with Example 1, the difference is only that the organic modified vanadium dioxide in Example 1 is replaced by the product obtained in Comparative Example 2 in equal mass.

[0066] Comparative Example 5 An intelligent early warning cable, compared with Example 2, the difference is only that the organic modified vanadium dioxide in Example 2 is replaced by the product obtained in Comparative Example 2 in equal mass.

[0067] Comparative Example 6 An intelligent early warning cable, compared with Example 3, the difference is only that the organic modified vanadium dioxide in Example 3 is replaced by the product obtained in Comparative Example 2 in equal mass.

[0068] Comparative Example 7 An intelligent early warning cable, compared with Example 1, the difference is only that the 1-ethyl-3-methylimidazole hexafluorophosphate in Example 1 is replaced by γ-methacryloyloxypropyl trimethoxysilane in equal mass.

[0069] Comparative Example 8 An intelligent early warning cable, compared with Example 2, the difference is only that the 1-octyl-3-methylimidazole hexafluorophosphate in Example 2 is replaced by γ-methacryloyloxypropyl trimethoxysilane in equal mass.

[0070] Comparative Example 9 An intelligent early warning cable, compared with Example 3, the difference is only that the 1-tetradecyl-3-methylimidazole hexafluorophosphate in Example 3 is replaced by γ-methacryloyloxypropyl trimethoxysilane in equal mass.

[0071] The sheath layer of the cable obtained in Example 1-Example 9 and Comparative Example 1-Comparative Example 9 is stripped off from the cable, prepared into a sample to be tested and tested for performance, and the test items and test process are as follows: (1) Thermochromic performance: The test uses Lab mode in PhotoShop software to collect color. First, take a picture of the sample at room temperature, then put the sample into a 75℃ constant temperature box for 10-20 minutes, and take a picture of the sample after the color changes. Cut the pictures to the same size, use the straw tool in PhotoShop software to measure the Lab value of 5 points, get the average value, then get the lightness index (L), red-green index (a) and yellow-blue index (b) of the sample surface according to the CIE-Lab color system of the International Commission on Illumination, and finally calculate the color difference value (ΔE) before and after heating. The larger the color difference value (ΔE) is, the more obvious the color change is; (2) Tensile strength: refer to standard GB / T1040-2006 for testing; (3) Flame retardant performance: refer to standard GB / T2406 for testing the limiting oxygen index; (4) Thermochromic stability: place the sample to be tested in a constant temperature air drying oven for heat air aging experiment, and get the aged sample after aging at 210℃ for 72 hours. Test the thermochromic performance of the aged sample according to (1), and calculate the color difference value (ΔE) retention rate; The results are shown in Table 1: Table 1 Analyzing the data recorded in Table 1, it can be seen from the test results of Example 1-Example 9 that the color difference value (ΔE) of the cable sheath prepared in Example 1-Example 9 after thermochromic change is 56.0-60.4, the tensile strength is 11.5-13.0 MPa, the limiting oxygen index is 30.7-33.8%, and the color difference value (ΔE) retention rate after thermal aging is 96.0-98.3%, indicating that the cable sheath prepared by the present application has good thermochromic performance, flame retardant performance and mechanical properties, which is more conducive to the practical application of low voltage.

[0072] From the test results of Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Example 3 and Comparative Example 3, it can be seen that replacing p-phenylene diisothiocyanate with equimolar p-phenylene diisothiocyanate in the preparation process of the modified vanadium dioxide of the present application cannot form thiourea bonds, resulting in a significant decrease in the flame retardant performance and thermochromic stability of the cable sheath.

[0073] From the test results of Example 1 and Comparative Example 4, Example 2 and Comparative Example 5, and Example 3 and Comparative Example 6, it can be seen that replacing the modified vanadium dioxide of the present application with amino vanadium dioxide will result in a significant decrease in the tensile strength, flame retardant performance and thermochromic stability of the cable sheath due to the collapse of the hyperbranched polymer.

[0074] As can be seen from the test results of the three groups of examples 1 and comparative example 7, example 2 and comparative example 8, example 3 and comparative example 9, replacing the ion liquid modified aluminum hydroxide salt prepared according to the present application with conventional vinyl siloxane modified aluminum hydroxide will result in a significant decrease in the tensile strength and flame retardant performance of the cable sheath material.

[0075] It should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one entity or action from another, without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0076] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, alternatives, and variations can be made in the embodiments without departing from the spirit and scope of the present application as defined by the appended claims and their equivalents.

Claims

1. A smart early warning cable comprising, from the inside to the outside, a conductor core, an insulating layer and a sheath layer, wherein the sheath layer is made of a flame-retardant polyolefin composite material, characterized in that, The flame-retardant polyolefin composite comprises the following raw materials by weight: 5-10 parts of ethylene-vinyl acetate copolymer, 10-20 parts of linear low-density polyethylene, 10-15 parts of ethylene-octene copolymer, 3-8 parts of a compatibilizer, 15-20 parts of organic modified vanadium dioxide, 30-40 parts of ionic liquid modified aluminum hydroxide, 1-1.5 parts of a crosslinking agent, and 1-2 parts of a lubricant; The raw materials for preparing the organic modified vanadium dioxide include amino vanadium dioxide, tris(3-aminophenyl)phosphine oxide, and p-phenylene diisothiocyanate, and the mass ratio of the amino vanadium dioxide, tris(3-aminophenyl)phosphine oxide, and p-phenylene diisothiocyanate is 3.8-4.5:12.1:7.

2.

2. The intelligent early warning cable of claim 1, wherein, The preparation steps of the organic modified vanadium dioxide are as follows: The amino vanadium dioxide, tris(3-aminophenyl)phosphine oxide, p-phenylene diisothiocyanate, and N,N-dimethylformamide are added into a reaction kettle, and stirred at room temperature for 8-10 hours; after the reaction is completed, the filter cake is washed and dried to obtain the organic modified vanadium dioxide.

3. The intelligent early warning cable of claim 2, wherein, The raw materials for preparing the amino vanadium dioxide include nano vanadium dioxide and amino siloxane, and the mass ratio of the nano vanadium dioxide and the amino siloxane is 1-2:

1.

4. The intelligent early warning cable of claim 3, wherein, The amino siloxane is N-(2-aminoethyl)-3-aminopropyl trimethoxysilane and / or 3-aminopropyl triethoxysilane.

5. The intelligent warning cable of claim 1, wherein, The raw materials for preparing the ionic liquid modified aluminum hydroxide include hexafluorophosphate ionic liquid and aluminum hydroxide, and the mass ratio of the hexafluorophosphate ionic liquid and the aluminum hydroxide is 2-3:7-8.

6. The intelligent warning cable of claim 5, wherein, The hexafluorophosphate ionic liquid is at least one of 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-octyl-3-methylimidazolium hexafluorophosphate, and 1-tetradecyl-3-methylimidazolium hexafluorophosphate.

7. The intelligent warning cable of claim 5, wherein, The preparation steps of the ionic liquid modified aluminum hydroxide are as follows: The hexafluorophosphate ionic liquid is added with petroleum ether in an amount of 5-10 times the volume of the hexafluorophosphate ionic liquid, and then the aluminum hydroxide is added after being uniformly stirred; the mixture is ultrasonically treated at room temperature for 0.5-2 hours, and finally filtered; the filter cake is dried in an oven at 80-100°C for 24 hours to obtain the ionic liquid modified aluminum hydroxide.

8. The intelligent warning cable of claim 1, wherein, The preparation steps of the flame-retardant polyolefin composite are as follows: The ethylene-vinyl acetate copolymer, the linear low-density polyethylene, the ethylene-octene copolymer, the compatibilizer, the organic modified vanadium dioxide, the ionic liquid modified aluminum hydroxide, the crosslinking agent, and the lubricant are placed in a banbury mixer, and mixed at a temperature of 130-150°C and a rotation speed of 40-50 rpm for 10-15 minutes; then the mixture is transferred to a twin-screw extruder and extruded at a temperature of 120-160°C to obtain the flame-retardant polyolefin composite.

9. The intelligent warning cable of claim 1, wherein, The crosslinking agent is at least one of triallyl cyanurate, triallyl isocyanurate, trimethylolpropane trihydroxy trimethacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate.

10. A method for manufacturing a smart early warning cable, characterized in that, The method for preparing the intelligent early warning cable of any one of claims 1-9 comprises the following steps: S1, an insulating layer is formed on the surface of a conductor core by using an extrusion process to coat a polyvinyl chloride material on the surface of the conductor core to obtain an insulated wire core; S2, the halogen-free flame-retardant polyolefin composite material is coated on the surface of the insulated core by an extrusion process, and then irradiation crosslinking is performed to form a sheath layer, thereby obtaining an intelligent early warning cable.

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