High-temperature-resistant special wire cable

Abstract

The invention discloses a high-temperature-resistant special wire cable, and belongs to the technical field of special cables. The cable sequentially comprises a cable core, a filling material, a wrapping layer, a shielding layer and a sheath layer from inside to outside. Wherein the sheath layer is prepared from the following raw materials in parts by weight: 70-90 parts of low-density polyethylene, 12-20 parts of stearic acid modified aluminum nitride, 6-12 parts of a flame-retardant aid, 2-4 parts of a cross-linking agent, 1-3 parts of a processing aid and 1-2 parts of an antioxidant. Wherein stearic acid modified aluminum nitride has good compatibility with a matrix, so that the heat resistance of the cable is greatly improved; the flame-retardant additive can improve the flame retardance and high temperature resistance of the cable at the same time, the performance is stable, and the insulating layer is made of silicone rubber, so that the high temperature resistance of the cable is further improved; therefore, the cable prepared by the invention has high temperature resistance and flame retardance, is stable in performance, and meets the high temperature and high reliability requirements of the new energy automobile on the cable.

Description

Technical Field

[0001] This invention belongs to the field of special cable technology, specifically, it relates to a high-temperature resistant special wire and cable. Background Technology

[0002] Against the backdrop of rapid development in modern industry and technology, the new energy vehicle industry, as an emerging industry, places extremely stringent performance requirements on related basic components due to its technological evolution. As the "blood vessels and nerves" of a vehicle, electrical wires and cables bear the critical functions of power transmission and signal control; their reliability directly affects the safety, efficiency, and lifespan of the entire vehicle. However, the internal environment of new energy vehicles, especially pure electric and hybrid models, differs significantly from that of traditional vehicles, bringing unprecedented challenges to the application of cables. During vehicle operation, cables need to be laid in high-temperature areas such as around the motor, electronic control system, battery pack, and charging system. The long-term operating temperature of these parts may reach 125°C to 150°C, and the instantaneous temperature may even exceed 200°C. Simultaneously, under conditions of rapid charging and high-current discharging, the conductors themselves also generate a large amount of Joule heat, causing the cable temperature to accumulate and rise further.

[0003] Currently, commonly used high-temperature resistant wire and cable insulation materials in the industry mainly include polytetrafluoroethylene (PTFE), silicone rubber, cross-linked polyethylene (XLPE), and polyimide. Among them, XLPE is one of the most commonly used insulation materials in the wire and cable field. From a cost perspective, compared with high-temperature resistant materials such as PTFE, silicone rubber, and polyimide, XLPE raw materials are easier to obtain, and the production process does not rely on special high-priced auxiliary materials or complex processes, resulting in significantly lower overall material costs. This effectively meets the industrial sector's demand for cable cost control. Furthermore, XLPE inherently possesses high mechanical strength, making it less prone to damage from minor external impacts or friction, thus better maintaining the integrity of the cable and reducing the risk of cable failure due to mechanical damage.

[0004] Cross-linked polyethylene (XLPE) requires modification to achieve its heat resistance. Traditional heat-resistant modification techniques typically involve adding fillers to improve heat resistance. However, since fillers are inorganic, their dispersion in organic materials is poor, leading to a decline in the overall material performance. Furthermore, XLPE has a low limiting oxygen index, making it a flammable material. It is highly flammable when exposed to open flames, and combustion is accompanied by molten droplets. These high-temperature droplets not only spread the flame and expand the fire, but can also drip directly onto battery packs, circuit boards, or other flammable components, causing secondary fires or even short circuits, exacerbating vehicle safety risks. Therefore, there is an urgent need to solve these problems and invent a special type of wire and cable that combines high-temperature resistance and flame retardancy to meet the higher requirements of the new energy vehicle sector. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-temperature resistant special wire and cable.

[0006] The objective of this invention can be achieved through the following technical solutions: A high-temperature resistant special wire and cable, from the inside out, includes a cable core, filler, wrapping layer, shielding layer and sheath layer.

[0007] As a further technical solution, the cable core includes a conductor and an insulation layer.

[0008] As a further technical solution, the conductor is made of multiple strands of soft copper wire twisted together.

[0009] As a further technical solution, the insulating layer is made of silicone rubber.

[0010] As a further technical solution, the filler is a PP mesh filler rope.

[0011] As a further technical solution, the material of the wrapping layer is polyester tape.

[0012] As a further technical solution, the material of the shielding layer is tin-plated copper wire.

[0013] As a further technical solution, the material of the sheath layer includes the following raw materials in parts by weight: 70-90 parts low-density polyethylene, 12-20 parts stearic acid modified aluminum nitride, 6-12 parts flame retardant additives, 2-4 parts crosslinking agent, 1-3 parts processing aids, and 1-2 parts antioxidants.

[0014] As a further technical solution, the stearic acid-modified aluminum nitride is prepared through the following steps: First, add nano-aluminum nitride and n-butanol to a flask and sonicate for 20-30 minutes to initially disperse the nano-aluminum nitride in the n-butanol. Then add stearic acid and sonicate again for 20-30 minutes. Start stirring and heat to 92-93℃. At this temperature, water and n-butanol form an azeotropic vapor. Separate the water using a separator and maintain this temperature for 2-3 hours. Then heat to 117-118℃ and reflux at this temperature for 4-6 hours. Once the reaction is complete, stop heating, filter, wash the filter cake 3-5 times with anhydrous ethanol, and vacuum dry to obtain stearic acid-modified aluminum nitride.

[0015] As a further technical solution, the mass ratio of the nano-aluminum nitride to stearic acid is 100:1-5.

[0016] Nano-aluminum nitride has extremely high temperature resistance. After being modified with stearic acid, it can be evenly dispersed in the polyethylene glycol matrix. It can quickly conduct local heat generated during cable operation, avoid excessively high hot spot temperature that could cause the sheath to soften, and greatly enhance the heat resistance of the sheath.

[0017] As a further technical solution, the flame retardant additive is prepared through the following steps: Step 1: In a dry three-necked flask, add 2-aminothiazole, 2,4-dihydroxybenzaldehyde, and ethylene glycol dimethyl ether in sequence. Purge with nitrogen for 10-20 minutes to remove air from the system. Turn on the stirrer and heat in an oil bath until the temperature reaches 80-85℃. React at this temperature for 1-2 hours until the reaction is complete. Then add 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and p-toluenesulfonic acid (catalyst). Keep the temperature constant and continue the reaction for 12-13 hours until the reaction is complete. After post-processing, obtain the intermediate product. Step 2: First, add the intermediate product and N,N-dimethylformamide to a dry three-necked flask, purge the air with dry nitrogen, start stirring, and slowly add sodium hydroxide powder. After the addition is complete, add allyl chloride dropwise through a constant pressure dropping funnel. After the addition is complete, heat the apparatus to 70-75℃ and react at a constant temperature for 8-10 hours. After the reaction is complete, perform post-processing to obtain the flame retardant additive.

[0018] As a further technical solution, in step one, the ratio of the amounts of 2-aminothiazole, 2,4-dihydroxybenzaldehyde, ethylene glycol dimethyl ether, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and p-toluenesulfonic acid is 10.1g:13.8g:150mL:22.3-23.1g:0.2g.

[0019] As a further technical solution, in step two, the ratio of the amount of intermediate product, N,N-dimethylformamide, sodium hydroxide powder, and allyl chloride is 43.6g:150mL:8.3-8.8g:16.3-17.7g.

[0020] The reaction formula for preparing the flame retardant additive of this invention is as follows: From the preparation process: This invention prepares a flame retardant additive in two steps. In step one, 2,4-dihydroxybenzaldehyde first undergoes a condensation reaction with 2-aminothiazole to form a double bond structure, and then reacts with DOPO to prepare an intermediate product. Next, the intermediate product is reacted with allyl chloride. In step two, the amounts of intermediate product and allyl chloride need to be strictly controlled to ensure that the above structure is obtained. The molar ratio of the two is controlled to be close to 1:2, and the latter is in excess, finally obtaining the flame retardant additive.

[0021] From the perspective of the performance of flame retardant additives: the prepared flame retardant additive molecules introduce thiazole, DOPO, and unsaturated double bonds. Among them, DOPO, as a phosphorus-based flame retardant, has excellent flame retardant properties. In addition, the thiazole molecule contains nitrogen and sulfur elements, which can play a synergistic role with DOPO in flame retardancy, significantly improving the flame retardant performance of the sheath. Moreover, the flame retardant additive molecules contain multiple benzene ring structures, which are rigid units and have excellent heat resistance. Furthermore, the thiazole ring is a five-membered heterocycle containing nitrogen and sulfur, which also has a certain degree of rigidity and can play a synergistic role with the benzene ring, improving the heat resistance of the sheath. Finally, since the prepared flame retardant additive has a small molecular structure, it is easy to migrate and exude in the sheath. The introduced unsaturated double bonds enable the flame retardant additive to participate in the crosslinking of polyethylene, improving the stability of the flame retardant additive.

[0022] As a further technical solution, the crosslinking agent is a peroxide crosslinking agent.

[0023] As a further technical solution, the processing aid is one of polyethylene wax, glyceryl monostearate, zinc stearate, and calcium stearate.

[0024] As a further technical solution, the antioxidant is obtained by compounding antioxidant 264 and antioxidant 168 in a mass ratio of 1:1.

[0025] The beneficial effects of this invention are: Advantage 1: This invention modifies nano-aluminum nitride with stearic acid, which improves the compatibility between nano-aluminum nitride and the matrix, making it easier to disperse and significantly improving the heat resistance of the cable. Advantage 2: This invention has a self-made flame retardant additive containing phosphorus, nitrogen and sulfur elements, which realizes a multiple synergistic flame retardant mechanism, greatly improves the flame retardancy of the cable, effectively prevents flame spread and dripping, and improves the safety of the whole vehicle. Advantage 3: The self-made flame retardant additive can further improve the high temperature resistance of the cable, and its performance is more stable compared with traditional small molecule additives; Advantage 4: The insulation layer uses silicone rubber, which further improves the cable's high temperature resistance; Therefore, the cable produced by this invention has both high temperature resistance and flame retardancy, and its performance is stable, meeting the high temperature and high reliability requirements of new energy vehicles for cables. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1 Preparation of stearic acid-modified aluminum nitride: First, 100g of nano-aluminum nitride and n-butanol were added to a flask and ultrasonically vibrated for 20 minutes to initially disperse the nano-aluminum nitride in the n-butanol. Then, 1g of stearic acid was added, and the mixture was ultrasonically vibrated again for 20 minutes. The stirring was then turned on, and the temperature was first raised to 92℃. At this temperature, water and n-butanol formed an azeotropic vapor. The water was separated by a separator and maintained for 2 hours. Then, the temperature was raised to 117℃ and refluxed for 4 hours. After the reaction was completed, the heating was stopped, the mixture was filtered, and the filter cake was washed three times with anhydrous ethanol and dried under vacuum to obtain stearic acid-modified aluminum nitride.

[0028] Example 2 Preparation of stearic acid-modified aluminum nitride: First, 100g of nano-aluminum nitride and n-butanol were added to a flask and ultrasonically vibrated for 30 minutes to initially disperse the nano-aluminum nitride in the n-butanol. Then, 5g of stearic acid was added, and the mixture was ultrasonically vibrated again for 30 minutes. The stirring was then turned on, and the temperature was first raised to 93℃. At this temperature, water and n-butanol formed an azeotropic vapor. The water was separated by a separator and maintained for 3 hours. Then, the temperature was raised to 118℃ and refluxed for 6 hours. After the reaction was completed, the heating was stopped, the mixture was filtered, and the filter cake was washed 5 times with anhydrous ethanol and dried under vacuum to obtain stearic acid-modified aluminum nitride.

[0029] Example 3 Preparation of flame retardant additives: Step 1: In a dry three-necked flask, add 10.1g of 2-aminothiazole, 13.8g of 2,4-dihydroxybenzaldehyde, and 150mL of ethylene glycol dimethyl ether in sequence. Purge the system with nitrogen for 10 minutes to remove air. Turn on the stirrer and heat in an oil bath until the temperature reaches 80℃. React at this temperature for 1 hour. After the reaction is complete, add 22.3g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 0.2g of p-toluenesulfonic acid. Keep the temperature constant and continue to react for 12 hours. After the reaction is complete, transfer the reaction solution to a rotary evaporator and concentrate it. Slowly pour the concentrate into an ice-water bath and stir magnetically to precipitate the solid. Collect the solid by filtration, wash with ethanol, and dry under vacuum to obtain the intermediate product. Step 2: In a dry three-necked flask, add 43.6 g of intermediate product and 150 mL of N,N-dimethylformamide. Purge the air with dry nitrogen, turn on the stirrer, and slowly add 8.3 g of sodium hydroxide powder. After the addition is complete, add 16.3 g of allyl chloride dropwise through a constant pressure dropping funnel. After the addition is complete, heat the apparatus to 70°C and react at a constant temperature for 8 hours. After the reaction is complete, turn off the heating device, cool to room temperature, add to deionized water, stir, add ethyl acetate and shake, allow to stand and separate into layers, collect the upper organic phase, wash with saturated brine and deionized water in sequence, add anhydrous sodium sulfate to the organic phase to dry, rotary evaporate, wash with anhydrous ethanol, and vacuum dry to obtain the flame retardant additive. A high-temperature resistant special wire and cable is manufactured through the following steps: Multiple strands of soft copper wire are stranded together using a stranding machine to form a conductor. Silicone rubber (Dow Chemical, SE6770) is then added to an extruder for coating, forming an insulation layer to obtain the cable core. Four cable cores are arranged in a circular pattern and placed on the cable-laying machine's pay-off frame. PP mesh filler rope is evenly filled into the gaps between the cable cores using a filling device. Polyester tape is then wrapped around the cores to form a wrapping layer. Outside the wrapping layer, tinned copper wire is braided into a dense shielding layer using a braiding machine. Finally, 70 parts of low-density polyethylene... Twelve parts of stearic acid-modified aluminum nitride prepared in Example 1, six parts of flame retardant additive, two parts of di-tert-butyl peroxide, one part of polyethylene wax, and one part of antioxidant (0.5 parts of antioxidant 264 and 0.5 parts of antioxidant 168 compounded) were added to an extruder for melt blending. The molten sheath material was then tightly extruded onto the outside of the shielding layer to form a sheath layer. The material was then immediately fed into a high-temperature crosslinking pipeline for crosslinking. After crosslinking was completed, the material was cooled and shaped in a cooling water tank to obtain a high-temperature resistant special wire and cable.

[0030] Example 4 Preparation of flame retardant additives: Step 1: In a dry three-necked flask, add 10.1g of 2-aminothiazole, 13.8g of 2,4-dihydroxybenzaldehyde, and 150mL of ethylene glycol dimethyl ether in sequence. Purge the system with nitrogen for 20min to remove air. Turn on the stirrer and heat in an oil bath until the temperature reaches 85℃. React at this temperature for 2h. After the reaction is complete, add 23.1g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 0.2g of p-toluenesulfonic acid. Keep the temperature constant and continue to react for 13h. After the reaction is complete, transfer the reaction solution to a rotary evaporator and concentrate it. Slowly pour the concentrate into an ice-water bath and stir magnetically to precipitate the solid. Collect the solid by filtration, wash with ethanol, and dry under vacuum to obtain the intermediate product. Step 2: In a dry three-necked flask, add 43.6 g of intermediate product and 150 mL of N,N-dimethylformamide. Purge the air with dry nitrogen, turn on the stirrer, and slowly add 8.8 g of sodium hydroxide powder. After the addition is complete, add 17.7 g of allyl chloride dropwise through a constant pressure dropping funnel. After the addition is complete, heat the apparatus to 75°C and react at a constant temperature for 10 h. After the reaction is complete, turn off the heating device, cool to room temperature, add to deionized water, stir, add ethyl acetate and shake, let stand to separate the layers, collect the upper organic phase, and wash it successively with saturated brine and deionized water. Add anhydrous sodium sulfate to the organic phase to dry it, rotary evaporate it, wash it with anhydrous ethanol, and vacuum dry it to obtain the flame retardant additive. A high-temperature resistant special wire and cable is manufactured through the following steps: Multiple strands of soft copper wire are stranded together using a stranding machine to form a conductor. Silicone rubber (Dow Chemical, SE6770) is then added to an extruder for coating, forming an insulation layer to obtain the cable core. Four cable cores are arranged in a circular pattern and placed on the cable-laying machine's pay-off frame. PP mesh filler rope is evenly filled into the gaps between the cable cores using a filling device. Polyester tape is then wrapped around the cores to form a wrapping layer. Outside this wrapping layer, tinned copper wire is braided into a dense shielding layer using a braiding machine. Finally, 80 parts of low-density polyethylene are added... 16 parts of stearic acid-modified aluminum nitride prepared in Example 2, 9 parts of flame retardant additive, 3 parts of di-tert-butyl peroxide, 2 parts of polyethylene wax, and 2 parts of antioxidant (1 part of antioxidant 264 and 1 part of antioxidant 168 are compounded) are added to an extruder for melt blending. The molten sheath material is then tightly extruded onto the outside of the shielding layer to form a sheath layer. The material is then immediately fed into a high-temperature crosslinking pipeline for crosslinking. After crosslinking is completed, the material is cooled and shaped in a cooling water tank to obtain a high-temperature resistant special wire and cable.

[0031] Example 5 The only difference between this embodiment and Embodiment 4 is that, in this embodiment, a high-temperature resistant special wire and cable is prepared through the following steps: Multiple strands of soft copper wire are stranded together using a stranding machine to form a conductor. Silicone rubber (Dow Chemical, SE6770) is then added to an extruder for coating, forming an insulation layer to obtain the cable core. Four cable cores are arranged in a circular pattern and placed on the cable-laying machine's pay-off frame. PP mesh filler rope is evenly filled into the gaps between the cable cores using a filling device. Polyester tape is then wrapped around the cores to form a wrapping layer. Outside this wrapping layer, tinned copper wire is braided into a dense shielding layer using a braiding machine. Finally, 90 parts of low-density polyethylene are applied. 20 parts of stearic acid modified aluminum nitride prepared in Example 2, 12 parts of flame retardant additive, 4 parts of di-tert-butyl peroxide, 3 parts of calcium stearate, and 2 parts of antioxidant (1 part of antioxidant 264 and 1 part of antioxidant 168 are compounded) are added to an extruder for melt blending. The molten sheath material is then tightly extruded onto the outside of the shielding layer to form a sheath layer. The sheath layer is then immediately fed into a high-temperature crosslinking pipeline for crosslinking. After crosslinking is completed, the material is cooled and shaped in a cooling water tank to obtain a high-temperature resistant special wire and cable.

[0032] Comparative Example 1 The only difference between this comparative example and Example 5 is that in this comparative example, an equal amount of DOPO is used as a flame retardant to replace the flame retardant additive, and a cable is obtained.

[0033] Comparative Example 2 The only difference between this comparative example and Example 5 is that in this comparative example, an equal amount of unmodified nano-aluminum nitride was used to replace stearic acid-modified aluminum nitride to obtain the cable.

[0034] The sheath layer materials from Examples 3, 4, and 5, and Comparative Examples 1, 2, and 3 were extruded separately and subjected to the following performance tests: The heat distortion temperature was determined according to GB / T 1634.1-2019 "Determination of Deflection Temperature of Plastics under Load - Part 1: General Test Method". The oxygen index was determined according to GB / T 2406-2008 "Determination of Combustion Behavior by Oxygen Index Method for Plastics". After storing the samples from Examples 3, 4, 5 and Comparative Example 1 at room temperature for 300 days, the oxygen index was determined using the same test standards described above. The test results of the samples are shown in Table 1: Table 1 Test Project Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Heat distortion temperature / ℃ 135 142 151 128 120 Limiting oxygen index / % 33.0 33.7 34.1 28.2 33.9 Limiting oxygen index (after 300 days) / % 32.5 33.1 33.5 26.7 / As can be seen from the measurement results in Table 1, the oxygen index and heat distortion temperature of the sheath material prepared in the embodiment of the present invention are higher than those of the comparative example. Therefore, the cable prepared by the present invention has both high temperature resistance and flame retardancy, and its performance is stable, meeting the high temperature and high reliability requirements of new energy vehicles for cables.

[0035] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A high-temperature resistant special wire and cable, comprising, from the inside out, a cable core, a filler, a wrapping layer, a shielding layer, and a sheath layer, characterized in that, The material of the sheath layer includes the following raw materials in parts by weight: 70-90 parts low-density polyethylene, 12-20 parts stearic acid modified aluminum nitride, 6-12 parts flame retardant additives, 2-4 parts crosslinking agent, 1-3 parts processing aids, and 1-2 parts antioxidants.

2. The high-temperature resistant special wire and cable according to claim 1, characterized in that, The flame retardant additive is prepared by the following steps: Step 1: Add 2-aminothiazole, 2,4-dihydroxybenzaldehyde and ethylene glycol dimethyl ether to a flask in sequence, purge with nitrogen to remove air, start stirring, and heat in an oil bath at 80-85℃ for 1-2 hours until the reaction is complete. Then add 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and p-toluenesulfonic acid, and continue the reaction for 12-13 hours until the reaction is complete, yielding the intermediate product. Step 2: First, add the intermediate product and N,N-dimethylformamide to the flask, purge the air with nitrogen, start stirring, add sodium hydroxide powder, and after the addition is complete, add allyl chloride dropwise. After the addition is complete, react at 70-75℃ for 8-10 hours. Once the reaction is complete, the flame retardant additive is obtained.

3. The high-temperature resistant special wire and cable according to claim 2, characterized in that, In step one, the ratio of the amounts of 2-aminothiazole, 2,4-dihydroxybenzaldehyde, ethylene glycol dimethyl ether, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and p-toluenesulfonic acid is 10.1g:13.8g:150mL:22.3-23.1g:0.2g.

4. The high-temperature resistant special wire and cable according to claim 2, characterized in that, In step two, the ratio of the intermediate product, N,N-dimethylformamide, sodium hydroxide powder, and allyl chloride is 43.6g:150mL:8.3-8.8g:16.3-17.7g.

5. A high-temperature resistant special wire and cable according to claim 1, characterized in that, The stearic acid-modified aluminum nitride is prepared by the following steps: First, add nano-aluminum nitride and n-butanol into a flask and sonicate for 20-30 minutes. Then add stearic acid and sonicate for another 20-30 minutes. Turn on the stirrer, raise the temperature to 92-93℃ and maintain it for 2-3 hours. Then heat to 117-118℃ and reflux for 4-6 hours. Once the reaction is complete, stearic acid-modified aluminum nitride is obtained.

6. The high-temperature resistant special wire and cable according to claim 5, characterized in that, The mass ratio of the nano-aluminum nitride to stearic acid is 100:1-5.

7. The high-temperature resistant special wire and cable according to claim 1, characterized in that, The processing aid is one of polyethylene wax, glyceryl monostearate, zinc stearate, and calcium stearate.

8. The high-temperature resistant special wire and cable according to claim 1, characterized in that, The antioxidant is obtained by compounding antioxidant 264 and antioxidant 168 in a mass ratio of 1:

1.

9. A high-temperature resistant special wire and cable according to claim 1, characterized in that, The insulating layer is made of silicone rubber.

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