A thermally conductive insulating cable material and a preparation method thereof

Abstract

The present invention relates to the technical field of cable materials, and specifically discloses a thermally conductive insulating cable material and a preparation method thereof. The thermally conductive insulating cable material preparation method includes: dispersing hexagonal boron nitride in water, adding sulfuric acid solution, hydrogen peroxide solution, stirring in a constant temperature water bath, cooling, centrifuging, drying, adding tetraisopropyl titanate, ethylene glycol, an antioxidant, terephthalic acid, stirring in a constant temperature oil bath, reducing the system pressure and stirring, cooling in a vacuum environment, and obtaining activated polyethylene terephthalate; adding spherical boron nitride and dopamine hydrochloride to a Tris-HCl buffer solution and ultrasonicating, adding amino-terminated polyamidoamine and ultrasonicating, centrifuging, washing, drying, and obtaining activated boron nitride; mixing activated polyethylene terephthalate and activated boron nitride, stirring, extruding, cooling, and obtaining a thermally conductive insulating cable material. The cable material of the present invention has good thermal conductivity and insulation, and a simple preparation method.

Description

Technical Field

[0001] The present invention relates to the technical field of cable materials, and in particular to a heat-conducting insulating cable material and a preparation method thereof. Background Art

[0002] In today's highly electrified era, cables, as key components of power transmission, have a direct impact on the operational efficiency and safety of the entire power system. Polyethylene terephthalate (PET), known for its excellent mechanical strength and corrosion resistance, is often used as a base material for cables. However, in actual use, this material has significant shortcomings in thermal conductivity and insulation.

[0003] While polyethylene terephthalate (PET)-based cables possess a certain degree of insulation resistance, which can prevent some current leakage, in actual use, due to the combined influence of everyday environmental factors such as temperature fluctuations and electromagnetic interference, their molecular structure polarizes, gradually creating tiny current channels within the cable material. Over time, these channels expand, increasing the risk of current leakage and ultimately causing insulation breakdown, seriously threatening the safe and stable operation of electrical systems.

[0004] Polyethylene terephthalate (PET) has a low thermal conductivity. When a cable is in operation, current flowing through it inevitably generates heat due to its inherent resistance. In high-power transmission scenarios or when cables are densely laid, the amount of heat generated is even greater and difficult to dissipate quickly. Due to PET's poor thermal conductivity, heat cannot be effectively transferred away, causing it to accumulate within the cable. This heat accumulation not only increases the temperature of the cable material itself but also changes its physical and chemical properties as the temperature rises. For example, the material's mechanical strength decreases with increasing temperature, making the cable more susceptible to damage from external mechanical stresses such as stretching and bending. High temperatures also accelerate the aging process of cable materials, significantly shortening their service life. Furthermore, excessively high temperatures within the cable can pose potential safety hazards, such as fires, and cause serious damage to the power system.

[0005] CN 109836772 A discloses a thermally conductive cable material that improves the thermal conductivity of the cable by modifying carbon nanotubes with a silane coupling agent during the preparation of epoxy resin. Carbon nanotubes themselves have excellent thermal conductivity and mechanical properties. Phenolic resin is evenly distributed on the surface of the carbon nanotubes and crosslinked and vulcanized. This modification increases the non-polarity of the carbon nanotubes. Then, under the action of substances such as styrene-butadiene rubber and zinc oxide, EPDM rubber and the carbon nanotubes are crosslinked and cured, forming a complex crosslinked network and numerous heat-conducting channels, significantly improving the thermal conductivity of the cable material. However, tourmaline itself is a mineral material with piezoelectric and thermoelectric properties. When subjected to mechanical stress or temperature changes during cable use, it will introduce additional electric fields or currents within the material, interfering with the normal electrical properties of the cable and adversely affecting its insulation. Carbon fiber also has high electrical conductivity. If unevenly dispersed in the cable material, it will form localized conductive areas, further affecting the insulation performance of the cable material.

[0006] CN 115458212 A discloses a kind of cable insulation and withstand voltage material and preparation method thereof, by mixing, sintering and grinding nanometer-scale aluminum nitride micropowder, micron-scale mica micropowder and micron-scale glass microbeads, then treating with silane coupling agent KH560, obtain composite voltage-stabilizing filler.After the composite voltage-stabilizing filler is mixed with octa-aminophenyl-POSS, it is added into the prepolymer solution generated by the reaction of p-phenylenediamine and pyromellitic dianhydride to form a stable withstand voltage layer, thereby improving the insulation of cable material. However, the cable material has limitations in thermal conductivity. Since mica micropowder has a flaky structure, although it helps to improve the insulation performance of the material to a certain extent, heat needs to bypass the mica lamella when it is transmitted along the cable material, which increases the path length of heat conduction and causes thermal conductivity to decrease. In addition, glass microbeads play the role of binder and pore-forming agent in the composite voltage-stabilizing filler, and its internal structure is relatively loose, containing more pores. However, these pores will increase the scattering and obstruction of heat transfer, making it difficult for heat to pass through smoothly, just like setting many "traps" on the heat conduction path, seriously affecting the thermal conductivity of the material.

[0007] In summary, given the serious deficiencies in thermal conductivity and insulation of traditional polyethylene terephthalate-based cable materials, there is an urgent need to develop a new type of cable material that can simultaneously possess excellent thermal conductivity and high insulation performance to meet the high performance requirements of modern power systems for cables. Summary of the Invention

[0008] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a method for preparing a heat-conducting insulating cable material.

[0009] A method for preparing a thermally conductive insulating cable material comprises the following steps:

[0010] S1. Dispersing hexagonal boron nitride in water, adding sulfuric acid solution and hydrogen peroxide solution, stirring in a constant temperature water bath, cooling, centrifuging, drying, adding tetraisopropyl titanate, ethylene glycol, antioxidant, and terephthalic acid, stirring in a constant temperature oil bath, reducing the system pressure while stirring, and cooling in a vacuum environment to obtain activated polyethylene terephthalate;

[0011] S2. Spherical boron nitride and dopamine hydrochloride are added to a Tris-HCl buffer with a pH value of 7.5-8, and then ultrasonicated. The amino-terminated polyamidoamine is added and ultrasonicated at a temperature of 70-80° C. The mixture is centrifuged, washed with deionized water, and vacuum-dried to obtain activated boron nitride.

[0012] S3. Mixing activated polyethylene terephthalate and activated boron nitride, stirring, extruding, and cooling to obtain a thermally conductive insulating cable material.

[0013] Preferably, the particle size of hexagonal boron nitride is 10-30 μm.

[0014] Preferably, the weight ratio of hexagonal boron nitride, 98-99% sulfuric acid solution, 30-40% hydrogen peroxide solution, tetraisopropyl titanate, ethylene glycol, antioxidant, and terephthalic acid is 0.5-1:0.5-1:1.5-2.5:0.03-0.08:1.2-1.8:0.01-0.08:1.8-3.

[0015] Preferably, in step S1, sulfuric acid solution is added at a rate of 10-20% per minute based on the total weight of the sulfuric acid solution.

[0016] Preferably, in step S1, after adding the hydrogen peroxide solution, stirring is carried out in a constant temperature water bath, the water bath temperature is 60-70° C., the stirring time is 4-6 hours, and the stirring speed is 300-500 r / min.

[0017] Preferably, in step S1, the drying temperature is 70-80°C and the drying time is 8-9 hours.

[0018] Preferably, in step S1 , the antioxidant is antioxidant 1010 .

[0019] Preferably, in step S1, terephthalic acid is added at a rate of 3-4% per minute based on the total weight of the terephthalic acid.

[0020] Preferably, in step S1, after adding terephthalic acid, stirring is carried out in a constant temperature oil bath, the oil bath temperature is 220-230° C., the stirring time is 3-4 h, and the stirring speed is 200-300 r / min.

[0021] Preferably, in step S1, the system pressure is reduced to 50-100 Pa by a vacuum pump and stirred for 2-3 hours at a stirring speed of 100-200 r / min.

[0022] Preferably, in step S2, the particle size of the spherical boron nitride is 10-50 μm.

[0023] Preferably, in step S2, the weight ratio of spherical boron nitride, dopamine hydrochloride, and amino-terminated polyamidoamine is 1-5:1-3:1-2.

[0024] Preferably, in step S3, the stirring time is 0.6-1 h, and the stirring speed is 600-700 r / min.

[0025] Preferably, in step S3, the extrusion is performed through a twin-screw extruder, the temperature of the plasticizing section is 230-250° C., the temperature of the die head is 230-240° C., the rotation speed is 80-100 r / min, and the extrusion speed is 3-5 g / min.

[0026] A heat-conducting insulating cable material is produced by adopting the preparation method of the heat-conducting insulating cable material.

[0027] Beneficial effects:

[0028] During the synthesis of polyethylene terephthalate (PET), hydroxylated hexagonal boron nitride (HBN), treated with sulfuric acid and hydrogen peroxide solutions, undergoes an esterification reaction with the carboxyl groups of terephthalic acid, tightly binding the HBN to the PET molecular chains. This significantly restricts the movement of electrons between the chains, reducing the electron conduction path and effectively improving the material's insulation. HBN inherently has high thermal conductivity. After being chemically bonded to the PET molecular chains through the aforementioned chemical reaction, a thermal conductivity channel is formed, allowing heat to be rapidly transferred through the HBN within the material, enhancing the overall thermal conductivity of the material.

[0029] The surface of spherical boron nitride is loaded with polydopamine and then grafted with polyamide amine. It can not only form ion bonds with the carboxyl groups on the activated polyethylene terephthalate chain, with high mutual bonding strength, but also the spherical boron nitride and hexagonal boron nitride jointly construct a three-dimensional thermal conductive structure. Experiments have found that the present invention can greatly improve the thermal conductivity performance while ensuring the insulation performance of the cable material in a high voltage environment.

[0030] In the present invention, hexagonal boron nitride and spherical boron nitride form a heat-conducting network in a polyethylene terephthalate matrix, forming a highly efficient heat-conducting system. Heat can be smoothly transferred within the system, and the bonding strength with the matrix is ​​high. Light protection ensures dispersion in the system, enabling a large filling effect. Through good bonding with polyethylene terephthalate, the boron nitride rapidly diffuses throughout the cable material, effectively preventing local overheating and ensuring long-term stable operation of the cable. The cable material preparation method of the present invention is simple, low-cost, and suitable for large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a comparison chart of the thermal conductivity and thermal diffusivity of the heat-conductive insulating cable materials obtained in Example 5 and Comparative Examples 1-2.

[0032] Figure 2 This is a comparison chart of the volume resistivity of the thermally conductive insulating cable materials obtained in Example 5 and Comparative Examples 1-2. DETAILED DESCRIPTION

[0033] The present invention will be further explained below with reference to specific embodiments.

[0034] The hexagonal boron nitride used below was purchased from Wuhan Kemik Biomedical Technology Co., Ltd., and its particle size was 10-30 μm; the spherical boron nitride used below was purchased from Shandong Pengcheng Ceramic New Materials Technology Co., Ltd., and its particle size was 10-50 μm.

[0035] Example 1

[0036] A method for preparing a thermally conductive insulating cable material comprises the following steps:

[0037] S1. Disperse 5 g of hexagonal boron nitride in 50 g of water, add 5 g of 98% sulfuric acid solution (based on the total weight of the sulfuric acid solution, the sulfuric acid solution is added at a rate of 10% per minute), add 15 g of 30% hydrogen peroxide solution, stir in a constant temperature water bath at 60 ° C for 4 h, stirring at a rate of 300 r / min, cool, centrifuge, and dry at 70 ° C for 8 h, add 0.3 g of tetraisopropyl titanate, 12 g of ethylene glycol, 0.1 g of antioxidant 1010, add 18 g of terephthalic acid (based on the total weight of terephthalic acid, the terephthalic acid is added at a rate of 3% per minute), stir in a constant temperature oil bath at 220 ° C for 3 h, stirring at a rate of 200 r / min, reduce the system pressure to 50 Pa by a vacuum pump and stir for 2 h, stirring at a rate of 100 r / min, and cool in a vacuum environment to obtain activated polyethylene terephthalate;

[0038] S2. Add 1 g of spherical boron nitride and 1 g of dopamine hydrochloride to 30 g of Tris-HCl buffer with a pH value of 7.5-8, sonicate for 5 min at a frequency of 10 kHz, add 1 g of amino-terminated polyamidoamine, continue sonicating for 1 h at a temperature of 70°C, centrifuge, wash with deionized water, and vacuum dry to obtain activated boron nitride;

[0039] S3. Mix activated polyethylene terephthalate and activated boron nitride, stir for 0.6 h at a stirring speed of 600 r / min, extrude through a twin-screw extruder, set the plasticizing section temperature at 230°C, the die head temperature at 230°C, the rotation speed at 80 r / min, and the extrusion speed at 3 g / min, and cool to obtain a thermally conductive insulating cable material.

[0040] Example 2

[0041] A method for preparing a thermally conductive insulating cable material comprises the following steps:

[0042] S1. Disperse 10 g of hexagonal boron nitride in 100 g of water, add 10 g of 99% sulfuric acid solution (based on the total weight of the sulfuric acid solution, the sulfuric acid solution is added at a rate of 20% per minute), add 25 g of 40% hydrogen peroxide solution, stir in a 70 ° C constant temperature water bath for 6 h, stirring at a speed of 500 r / min, cool, centrifuge, and dry at 80 ° C for 9 h, add 0.8 g of tetraisopropyl titanate, 18 g of ethylene glycol, 0.8 g of antioxidant 1010, add 30 g of terephthalic acid (based on the total weight of terephthalic acid, the terephthalic acid is added at a rate of 4% per minute), stir in a 230 ° C constant temperature oil bath for 4 h, stirring at a speed of 300 r / min, reduce the system pressure to 100 Pa by a vacuum pump and stir for 3 h, stirring at a speed of 200 r / min, and cool in a vacuum environment to obtain activated polyethylene terephthalate;

[0043] S2. Add 5 g of spherical boron nitride and 3 g of dopamine hydrochloride to 60 g of Tris-HCl buffer with a pH value of 7.5-8, sonicate for 15 min at a frequency of 15 kHz, add 2 g of amino-terminated polyamidoamine, continue sonication for 2 h at a temperature of 80° C., centrifuge, wash with deionized water, and vacuum dry to obtain activated boron nitride;

[0044] S3. Mix activated polyethylene terephthalate and activated boron nitride, stir for 1 hour at a stirring speed of 700 r / min, extrude through a twin-screw extruder, set the plasticizing section temperature at 250°C, the die head temperature at 240°C, the rotation speed at 100 r / min, and the extrusion speed at 5 g / min, and cool to obtain a thermally conductive insulating cable material.

[0045] Example 3

[0046] A method for preparing a thermally conductive insulating cable material comprises the following steps:

[0047] S1. Disperse 6 g of hexagonal boron nitride in 60 g of water, add 6 g of 98.2% sulfuric acid solution (based on the total weight of the sulfuric acid solution, the sulfuric acid solution is added at a rate of 12% per minute), add 17 g of 32% hydrogen peroxide solution, stir in a 62 ° C constant temperature water bath for 4.5 h, stirring at a speed of 350 r / min, cool, centrifuge, dry at 72 ° C for 8.2 h, add 0.4 g of tetraisopropyl titanate, 14 g of ethylene glycol, 0.3 g of antioxidant 1010, add 21 g of terephthalic acid (based on the total weight of terephthalic acid, the terephthalic acid is added at a rate of 3.2% per minute), stir in a 222 ° C constant temperature oil bath for 3.2 h, stirring at a speed of 220 r / min, reduce the system pressure to 60 Pa by a vacuum pump and stir for 2.2 h, stirring at a speed of 120 r / min, and cool in a vacuum environment to obtain activated polyethylene terephthalate;

[0048] S2. Add 2 g of spherical boron nitride and 1.5 g of dopamine hydrochloride to 40 g of Tris-HCl buffer with a pH value of 7.5-8, sonicate for 6 min at a frequency of 12 kHz, add 1.2 g of amino-terminated polyamidoamine, continue sonicating for 1.5 h at a temperature of 72° C., centrifuge, wash with deionized water, and vacuum dry to obtain activated boron nitride;

[0049] S3. Mix activated polyethylene terephthalate and activated boron nitride, stir for 0.7h at a stirring speed of 620r / min, extrude through a twin-screw extruder, with a plasticizing section temperature of 235°C, a die head temperature of 232°C, a rotation speed of 85r / min, and an extrusion speed of 3.5g / min, and cool to obtain a thermally conductive insulating cable material.

[0050] Example 4

[0051] A method for preparing a thermally conductive insulating cable material comprises the following steps:

[0052] S1. Disperse 9 g of hexagonal boron nitride in 90 g of water, add 9 g of 98.8% sulfuric acid solution (based on the total weight of the sulfuric acid solution, the sulfuric acid solution is added at a rate of 18% per minute), add 23 g of 38% hydrogen peroxide solution, stir in a 68 ° C constant temperature water bath for 5.5 h, stirring at a rate of 450 r / min, cool, centrifuge, dry at 78 ° C for 8.8 h, add 0.7 g of tetraisopropyl titanate, 16 g of ethylene glycol, 0.6 g of antioxidant 1010, add 27 g of terephthalic acid (based on the total weight of terephthalic acid, the terephthalic acid is added at a rate of 3.8% per minute), stir in a 228 ° C constant temperature oil bath for 3.8 h, stirring at a rate of 280 r / min, reduce the system pressure to 90 Pa by a vacuum pump and stir for 2.8 h, stirring at a rate of 180 r / min, and cool in a vacuum environment to obtain activated polyethylene terephthalate;

[0053] S2. Add 4 g of spherical boron nitride and 2.5 g of dopamine hydrochloride to 50 g of Tris-HCl buffer with a pH value of 7.5-8, sonicate for 12 min at a frequency of 12 kHz, add 1.5 g of amino-terminated polyamidoamine, continue sonicating for 1.5 h at a temperature of 75° C., centrifuge, wash with deionized water, and vacuum dry to obtain activated boron nitride;

[0054] S3. Mix activated polyethylene terephthalate and activated boron nitride, stir for 0.9h at a stirring speed of 680r / min, extrude through a twin-screw extruder, with a plasticizing section temperature of 245°C, a die head temperature of 238°C, a rotation speed of 95r / min, an extrusion speed of 4.5g / min, and cool to obtain a thermally conductive insulating cable material.

[0055] Example 5

[0056] A method for preparing a thermally conductive insulating cable material comprises the following steps:

[0057] S1. Disperse 7 g of hexagonal boron nitride in 70 g of water, add 7 g of 98.5% sulfuric acid solution (based on the total weight of the sulfuric acid solution, the sulfuric acid solution is added at a rate of 15% per minute), add 20 g of 35% hydrogen peroxide solution, stir in a 65 ° C constant temperature water bath for 5 h, stirring at a rate of 400 r / min, cool, centrifuge, dry at 75 ° C for 8.5 h, add 0.5 g of tetraisopropyl titanate, 15 g of ethylene glycol, 0.4 g of antioxidant 1010, add 24 g of terephthalic acid (based on the total weight of terephthalic acid, the terephthalic acid is added at a rate of 3.5% per minute), stir in a 225 ° C constant temperature oil bath for 3.5 h, stirring at a rate of 250 r / min, reduce the system pressure to 75 Pa by a vacuum pump and stir for 2.5 h, stirring at a rate of 150 r / min, and cool in a vacuum environment to obtain activated polyethylene terephthalate;

[0058] S2. Add 3.5 g of spherical boron nitride and 1.5 g of dopamine hydrochloride to 50 g of Tris-HCl buffer with a pH value of 7.5-8, sonicate for 10 min at a frequency of 12 kHz, add 1.2 g of amino-terminated polyamidoamine, continue sonication for 1.5 h at a temperature of 75° C., centrifuge, wash with deionized water, and vacuum dry to obtain activated boron nitride;

[0059] S3. Mix activated polyethylene terephthalate and activated boron nitride, stir for 0.8h at a stirring speed of 650r / min, extrude through a twin-screw extruder, with a plasticizing section temperature of 240°C, a die head temperature of 235°C, a rotation speed of 90r / min, and an extrusion speed of 4g / min, and cool to obtain a thermally conductive insulating cable material.

[0060] Comparative Example 1

[0061] A method for preparing a thermally conductive insulating cable material comprises the following steps:

[0062] S1. Disperse 7 g of spherical boron nitride in 70 g of water, add 7 g of 98.5% sulfuric acid solution (based on the total weight of the sulfuric acid solution, the sulfuric acid solution is added at a rate of 15% per minute), add 20 g of 35% hydrogen peroxide solution, stir in a 65 ° C constant temperature water bath for 5 h, stirring at a rate of 400 r / min, cool, centrifuge, dry at 75 ° C for 8.5 h, add 0.5 g of tetraisopropyl titanate, 15 g of ethylene glycol, 0.4 g of antioxidant 1010, add 24 g of terephthalic acid (based on the total weight of terephthalic acid, the terephthalic acid is added at a rate of 3.5% per minute), stir in a 225 ° C constant temperature oil bath for 3.5 h, stirring at a rate of 250 r / min, reduce the system pressure to 75 Pa by a vacuum pump and stir for 2.5 h, stirring at a rate of 150 r / min, and cool in a vacuum environment to obtain activated polyethylene terephthalate;

[0063] S2. Add 3.5 g of hexagonal boron nitride and 1.5 g of dopamine hydrochloride to 50 g of Tris-HCl buffer with a pH value of 7.5-8, ultrasonicate for 10 min at a frequency of 12 kHz, add 1.2 g of amino-terminated polyamidoamine, continue ultrasonicating for 1.5 h at a temperature of 75° C., centrifuge, wash with deionized water, and vacuum dry to obtain activated boron nitride;

[0064] S3. Mix activated polyethylene terephthalate and activated boron nitride, stir for 0.8h at a stirring speed of 650r / min, extrude through a twin-screw extruder, with a plasticizing section temperature of 240°C, a die head temperature of 235°C, a rotation speed of 90r / min, and an extrusion speed of 4g / min, and cool to obtain a thermally conductive insulating cable material.

[0065] Comparative Example 2

[0066] A method for preparing a thermally conductive insulating cable material comprises the following steps:

[0067] S1. Disperse 7 g of hexagonal boron nitride in 70 g of water, add 7 g of 98.5% sulfuric acid solution (based on the total weight of the sulfuric acid solution, the sulfuric acid solution is added at a rate of 15% per minute), add 20 g of 35% hydrogen peroxide solution, stir in a 65 ° C constant temperature water bath for 5 h, stirring at a rate of 400 r / min, cool, centrifuge, dry at 75 ° C for 8.5 h, add 0.5 g of tetraisopropyl titanate, 15 g of ethylene glycol, 0.4 g of antioxidant 1010, add 24 g of terephthalic acid (based on the total weight of terephthalic acid, the terephthalic acid is added at a rate of 3.5% per minute), stir in a 225 ° C constant temperature oil bath for 3.5 h, stirring at a rate of 250 r / min, reduce the system pressure to 75 Pa by a vacuum pump and stir for 2.5 h, stirring at a rate of 150 r / min, and cool in a vacuum environment to obtain activated polyethylene terephthalate;

[0068] S2. Add 3.5 g of hexagonal boron nitride and 1.5 g of dopamine hydrochloride to 50 g of Tris-HCl buffer with a pH value of 7.5-8, ultrasonicate for 10 min at a frequency of 12 kHz, add 1.2 g of amino-terminated polyamidoamine, continue ultrasonicating for 1.5 h at a temperature of 75° C., centrifuge, wash with deionized water, and vacuum dry to obtain activated boron nitride;

[0069] S3. Mix activated polyethylene terephthalate and activated boron nitride, stir for 0.8h at a stirring speed of 650r / min, extrude through a twin-screw extruder, with a plasticizing section temperature of 240°C, a die head temperature of 235°C, a rotation speed of 90r / min, and an extrusion speed of 4g / min, and cool to obtain a thermally conductive insulating cable material.

[0070] Test Example 1

[0071] The thermal conductivity and thermal diffusivity of the cable materials after treatment in Example 5 and Comparative Examples 1-2 were tested as follows:

[0072] Cut 10×10 mm square samples of equal weight from the cable materials prepared in Example 5, Comparative Examples 1, and 2, ensuring that the sample surfaces were flat, clean, and undamaged. Measure the dimensions of the cable material samples using a vernier caliper. Place the samples on the sample stage of a laser flash thermal conductivity meter (Model: LFA 467 HyperFlash), ensuring close contact between the sample and the stage to prevent air gaps from affecting the measurement results. Set appropriate measurement parameters, start the laser flash thermal conductivity meter, and emit laser pulses. After the measurement, the instrument automatically displays the thermal conductivity and thermal diffusivity results.

[0073] Depend on Figure 1 It can be seen that the thermal conductivity and thermal diffusivity of the cable materials prepared in Example 5 and Comparative Examples 1-2 are ranked in the order of Example 5 > Comparative Example 1 > Comparative Example 2, that is, the cable material prepared in Example 5 exhibits the best thermal conductivity, which is better than Comparative Examples 1-2 (P < 0.05).

[0074] Test Example 2

[0075] The volume resistivity of the cable materials after treatment in Example 5 and Comparative Examples 1-2 was tested as follows:

[0076] Cut 10×10 mm square samples of the same weight from the cable materials prepared in Example 5, Comparative Example 1, and Comparative Example 2, and ensure that the sample surfaces are flat, clean, and undamaged; measure the dimensions of the cable material samples with a vernier caliper; place the samples on a flat platform, use a spirit level to ensure that the platform is level, and then slowly place three electrodes (high-voltage electrode, measuring electrode, and guard electrode) on the sample, ensuring that the sample is placed flat on the electrodes and is in full contact with the electrodes; set an appropriate test voltage and measurement range on the high resistance meter (model: ZC-90F); start the high resistance meter, start measuring, record the data, and calculate the volume resistivity result according to the formula.

[0077] Calculate using the following formula: Volume resistivity (ρ) ,

[0078] R is the measured resistance value; S is the effective area of ​​the measuring electrode; d is the thickness of the sample.

[0079] Depend on Figure 2 It can be seen that the volume resistivity of the cable material prepared in Example 5 is the highest, showing the best insulation, while Comparative Example 1 is second and Comparative Example 2 is the worst, but there is no significant difference among the three (P>0.05).

[0080] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a thermally conductive insulating cable material, characterized in that: The steps include: S1. Dispersing hexagonal boron nitride in water, adding sulfuric acid solution and hydrogen peroxide solution, stirring in a constant temperature water bath, cooling, centrifuging, drying, adding tetraisopropyl titanate, ethylene glycol, antioxidant, and terephthalic acid, stirring in a constant temperature oil bath, reducing the system pressure while stirring, and cooling in a vacuum environment to obtain activated polyethylene terephthalate; S2. Spherical boron nitride and dopamine hydrochloride are added to a Tris-HCl buffer with a pH value of 7.5-8, and then ultrasonicated. The amino-terminated polyamidoamine is added and ultrasonicated at a temperature of 70-80° C. The mixture is centrifuged, washed with deionized water, and vacuum-dried to obtain activated boron nitride. S3. Mixing activated polyethylene terephthalate and activated boron nitride, stirring, extruding, and cooling to obtain a thermally conductive insulating cable material.

2. The method for preparing the thermally conductive insulating cable material according to claim 1, characterized in that: The weight ratio of hexagonal boron nitride, 98-99% sulfuric acid solution, 30-40% hydrogen peroxide solution, tetraisopropyl titanate, ethylene glycol, antioxidant, and terephthalic acid is 0.5-1:0.5-1:1.5-2.5:0.03-0.08:1.2-1.8:0.01-0.08:1.8-3.

3. The method for preparing the thermally conductive insulating cable material according to claim 1, characterized in that: In step S1, sulfuric acid solution is added at a rate of 10-20% per minute based on the total weight of the sulfuric acid solution.

4. The method for preparing the thermally conductive insulating cable material according to claim 1, characterized in that: In step S1, after adding the hydrogen peroxide solution, stirring is carried out in a constant temperature water bath with a water bath temperature of 60-70° C., a stirring time of 4-6 hours, and a stirring speed of 300-500 r / min.

5. The method for preparing the thermally conductive insulating cable material according to claim 1, characterized in that: In step S1, the drying temperature is 70-80°C and the drying time is 8-9 hours.

6. The method for preparing the thermally conductive insulating cable material according to claim 1, characterized in that: In step S1, terephthalic acid is added at a rate of 3-4% per minute based on the total weight of the terephthalic acid.

7. The method for preparing the thermally conductive insulating cable material according to claim 1, characterized in that: In step S1, after adding terephthalic acid, stirring is carried out in a constant temperature oil bath with an oil bath temperature of 220-230° C., a stirring time of 3-4 hours, and a stirring speed of 200-300 r / min.

8. The method for preparing the thermally conductive insulating cable material according to claim 1, characterized in that: In step S2, the weight ratio of spherical boron nitride, dopamine hydrochloride, and amino-terminated polyamidoamine is 1-5:1-3:1-2.

9. The method for preparing a thermally conductive insulating cable material according to claim 1, characterized in that: In step S3, the extruder is used for extrusion, with the temperature of the plasticizing section being 230-250° C., the temperature of the die head being 230-240° C., the rotation speed being 80-100 r / min, and the extrusion speed being 3-5 g / min.

10. A thermally conductive insulating cable material, characterized in that: The thermally conductive insulating cable is made by the preparation method of any one of claims 1 to 9.

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