High-flexibility environment-resistant copper-clad aluminum composite aviation cable and preparation method thereof

Abstract

The application discloses a kind of high flexibility environmental type copper-clad aluminum composite aviation cable and preparation method thereof, belong to aviation cable technical field.The cable includes conductor layer, inner layer bonding sublayer, outer layer weathering sublayer and sheath layer;The conductor layer is made of multiple annealed copper-clad aluminum filaments by layered variable-pitch stranding;The inner layer bonding sublayer and outer layer weathering sublayer are both with thermoplastic vulcanized rubber as matrix, and weathering additive containing self-made benzotriazole structure and C-F bond is added in outer layer weathering sublayer;The sheath layer is thermoplastic vulcanized rubber composite material.The application solves the problem of easy broken wire of copper-clad aluminum wire thin line diameter stranding by layered variable-pitch stranding process, simultaneously, using multilayer structure design and weathering additive, the environmental resistance ability such as ultraviolet resistance, corrosion resistance, high and low temperature impact resistance of cable is significantly improved, product has light weight, high flexibility and high reliability, and is suitable for unmanned aerial vehicle and other aircraft.

Description

Technical Field

[0001] This invention belongs to the field of aviation cable technology, specifically, it relates to a highly flexible and environmentally resistant copper-clad aluminum composite aviation cable and its preparation method. Background Technology

[0002] In recent years, the civilian drone and light aircraft industry has experienced explosive growth, rapidly becoming widespread in fields such as agricultural plant protection, geographic surveying and mapping, logistics and distribution, emergency rescue and low-altitude economy. As a core component of the aircraft's electrical system, the performance, weight and reliability of airborne cables directly determine the aircraft's range, load and operational safety.

[0003] The aerospace industry has long pursued lightweight design. Cables typically account for 5-15% of the total weight of an aircraft and are a key factor affecting flight endurance. Currently, the mainstream aviation cables use pure copper conductors, which have stable conductivity and reliable connections. However, their high density and weight significantly increase the load on the aircraft and shorten the flight range, making it difficult to meet the needs of long-endurance UAVs and light aircraft. Pure aluminum conductors, on the other hand, are lightweight and low-cost, but they have drawbacks such as low conductivity, susceptibility to oxidation and corrosion, poor flexibility, and weak bending resistance. Under the conditions of high-frequency vibration and frequent bending of aircraft, conductor breakage and poor contact are likely to occur, and the connection reliability cannot meet aviation-grade standards.

[0004] Copper-clad aluminum composite materials combine the excellent conductivity of copper with the lightweight advantages of aluminum, making them an ideal alternative for aerospace cable conductors. However, when manufacturing fine-diameter aerospace cables (such as AWG20-AWG28 specifications for UAVs), copper-clad aluminum wires are prone to breakage during the stranding process. This is because of the difference in ductility between the aluminum and copper layers, and the fact that traditional constant-pitch, constant-tension stranding processes cannot adapt to the brittle characteristics of copper-clad aluminum materials, resulting in low production yields and hindering large-scale mass production.

[0005] In addition, the sheath material also faces performance challenges. Drones often operate in harsh outdoor environments, including strong ultraviolet radiation, coastal salt spray corrosion, pesticide and chemical erosion, and alternating high and low temperature impacts. Traditional PVC sheaths are prone to aging and cracking under ultraviolet light, resulting in a short service life; while high-end fluoroplastics such as PTFE have excellent environmental resistance, their high material cost and processing difficulty make them unsuitable for the economic requirements of the civilian market. Therefore, it is urgent to solve these problems to meet the higher technical demands of the aviation cable technology field. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a highly flexible and environmentally resistant copper-clad aluminum composite aviation cable and its preparation method.

[0007] The objective of this invention can be achieved through the following technical solutions: A highly flexible and environmentally resistant copper-clad aluminum composite aviation cable includes a conductor layer, an inner adhesive sublayer, an outer weather-resistant sublayer, and a sheath layer.

[0008] Preferably, the conductor layer is formed by stranding multiple annealed copper-clad aluminum monofilaments through layered variable pitch.

[0009] Preferably, the volume percentage of the copper layer in the copper-clad aluminum monofilament is 10%-15%.

[0010] Preferably, in the layered variable pitch stranding, the inner layer stranding pitch L1 = 10-12d and the outer layer stranding pitch L2 = 14-16d.

[0011] Preferably, the material of the inner adhesive sublayer comprises the following raw materials in parts by weight: 80-100 parts thermoplastic vulcanized rubber, 6-8 parts maleic anhydride-grafted polypropylene, and 0.5-1 parts antioxidant.

[0012] Preferably, the material of the outer weather-resistant sublayer comprises the following raw materials in parts by weight: 80-100 parts thermoplastic vulcanized rubber, 15-20 parts nano zinc oxide, 3-6 parts weather-resistant additives, and 1-2 parts lubricant.

[0013] Preferably, the material of the sheath layer comprises the following raw materials in parts by weight: 80-100 parts thermoplastic vulcanized rubber, 20-30 parts flame retardant, 0.5-1 part antioxidant, and 2-3 parts lubricant.

[0014] Preferably, the lubricant is one of zinc stearate, calcium stearate, and oleamide.

[0015] Preferably, the flame retardant is a mixture of an inorganic flame retardant and a phosphorus-based flame retardant in a mass ratio of 4:1.

[0016] Preferably, the weather-resistant additive is prepared by the following steps: A1. In a dry three-necked flask, 3-amino-p-cresol was dissolved in anhydrous N,N-dimethylformamide, followed by the addition of perfluorovalerate. The mixture was cooled to 0-5°C in an ice-water bath with stirring. Then, 1-hydroxybenzotriazole and EDC·HCl were added sequentially, and stirring was continued for 20-30 min. N-methylmorpholine was added dropwise to adjust the pH of the reaction solution to 8. The ice bath was removed, and the mixture was heated to room temperature and stirred for 10-12 h. The reaction was completed. After post-treatment, the amidated product was obtained. The reaction formula for step A1 is as follows:

[0017] A2. In a four-necked flask, first add concentrated sulfuric acid (98% by mass) and water, then add o-nitroaniline while stirring. Cool to 0-5°C in an ice-water bath, then add sodium nitrite solution (30% by mass) dropwise. After the addition is complete, continue stirring for 1-1.5 hours. Once the reaction is complete, perform post-treatment to obtain a diazonium salt solution. A3. In a four-necked flask, first add the amidation product and N,N-dimethylformamide, stir well, cool in an ice-water bath to 0-5℃, then add sodium hydroxide solution (20% by mass) to adjust the pH to 7-9, and under this weakly alkaline condition, add the diazonium salt solution prepared in step A2 dropwise. After the addition is complete, continue the reaction for 2-3 hours. After the reaction is complete, perform post-processing to obtain the intermediate product. A4. In a four-necked flask, first add the intermediate product and N,N-dimethylformamide, stir well, cool in an ice-water bath to 0-5℃, slowly add sodium hydroxide solution (40% by mass) until the system is strongly alkaline (pH=12), after the addition is complete, remove the ice-water bath, heat to 60-70℃, finally add thiourea dioxide, and react at a constant temperature for 5-6 hours. After the reaction is complete, and after post-treatment, obtain the weather-resistant additive.

[0018] The reaction equations for steps A2-A4 are as follows:

[0019] Preferably, the ratio of the amounts of 3-amino-p-cresol, perfluorovalerate, 1-hydroxybenzotriazole and EDC·HCl in step A1 is 12.3g:26.4g:14.7g:20.5g.

[0020] Preferably, the ratio of concentrated sulfuric acid, o-nitroaniline, sodium nitrite and amidation product used in steps A2 and A3 is 27g:14.9g:40g:44.3g.

[0021] Preferably, the ratio of the intermediate product to thiourea dioxide in step A4 is 50.7g:34.5g.

[0022] As can be seen from the above reaction formula, the weather-resistant additive prepared in this invention belongs to the benzotriazole class of ultraviolet absorbers. The benzotriazole structure has a strong ultraviolet absorption capacity, preferentially absorbing the highest-energy ultraviolet wavelengths in sunlight, converting harmful ultraviolet light into harmless heat energy, thus improving the UV resistance of the matrix. Furthermore, the weather-resistant additive introduces CF bonds, which have high bond energies. These bonds not only resist thermal degradation during long-term outdoor use but also improve the chemical inertness of the matrix, preventing corrosion from acidic substances or environmental moisture, thus achieving long-term protection. The two groups in the weather-resistant additive molecule work together to significantly improve the environmental resistance of the matrix.

[0023] This invention also provides a method for preparing a highly flexible and environmentally resistant copper-clad aluminum composite aviation cable, comprising the following steps: Step 1: Multiple annealed copper-clad aluminum wires are layered and twisted with variable pitch in a mold to form a conductor layer; Step 2: Apply a coupling agent coating to the surface of the stranded conductor layer and air dry at room temperature to improve the bonding force between the insulation and the conductor; Step 3: Weigh the raw materials of the inner adhesive layer and the outer weather-resistant layer separately, add them to the double-layer co-extrusion extruder, and extrude the inner adhesive layer and the outer weather-resistant layer simultaneously onto the surface of the conductor layer, and then cool. Step 4: Finally, weigh the raw material for the sheath layer, add it to the extruder, extrude it to coat the surface of the outer weather-resistant layer, and after cooling, obtain a highly flexible and environmentally resistant copper-clad aluminum composite aviation cable.

[0024] Preferably, the mold is a ceramic-diamond composite guide mold with an entrance angle of 12-15°.

[0025] Preferably, the coupling agent is a silane coupling agent, and the dosage is 0.05-0.1 g / m.

[0026] Preferably, during the processing of the double-layer co-extrusion extruder, the temperature of the inner bonding layer is 190-200℃, and the temperature of the outer weather-resistant layer is 200-210℃.

[0027] Preferably, the cooling is performed using segmented warm water cooling, with the first segment at 50-60°C and the second segment at 30-40°C.

[0028] The beneficial effects of this invention are: 1. This invention uses copper-clad aluminum composite material as the conductor, which combines the excellent conductivity of copper with the lightweight advantage of aluminum, and significantly reduces the weight of the cable while ensuring electrical performance. 2. The conductor layer of this invention adopts a layered variable pitch stranding process, combined with annealed copper-clad aluminum monofilaments, which effectively solves the problem of easy breakage of copper-clad aluminum wires during stranding, and improves the flexibility and bending resistance of the cable. 3. By introducing self-made weather-resistant additives into the outer weather-resistant sublayer, the cable has strong ultraviolet absorption capacity, resistance to thermal degradation and chemical corrosion, which significantly extends its service life in harsh outdoor environments. In summary, this invention achieves lightweight, high flexibility, and excellent environmental resistance in cables through copper-clad aluminum composite conductors, layered variable pitch stranding, and weather-resistant structural design, and solves the mass production problem of easily broken copper-clad aluminum wires. Detailed Implementation

[0029] 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.

[0030] Example 1 Preparation of weather-resistant additives: A1. In a dry three-necked flask, 12.3 g of 3-amino-p-cresol was dissolved in 100 mL of anhydrous N,N-dimethylformamide, followed by the addition of 26.4 g of perfluorovalerate. The mixture was cooled to 0-5 °C in an ice-water bath with stirring. Then, 14.7 g of 1-hydroxybenzotriazole and 20.5 g of EDC·HCl were added sequentially, and stirring was continued for 20 min. N-methylmorpholine was added dropwise to adjust the pH of the reaction solution to 8. The ice bath was removed, and the mixture was heated to room temperature and stirred for 10 h. The reaction was completed. The reaction solution was poured into hydrochloric acid, and a solid precipitated. The solid was filtered, washed with water, and then washed with cold toluene to remove residual DMF. The crude product was recrystallized from ethyl acetate / n-hexane (1:2, volume ratio) to obtain the amidated product. A2. In a four-necked flask, first add 27g of concentrated sulfuric acid (98% by mass) and 70g of water, then add 14.9g of o-nitroaniline while stirring. Cool to 0-5℃ in an ice-water bath, then add 40g of sodium nitrite solution (30% by mass) dropwise. After the addition is complete, continue stirring and react for 1 hour. Once the reaction is complete, add urea to decompose the residual nitrite, filter to remove residue, and obtain a diazonium salt solution. A3. In a four-necked flask, first add 44.3g of the amidation product and 100mL of N,N-dimethylformamide. After stirring evenly, cool the mixture in an ice-water bath to 0-5℃. Then add sodium hydroxide solution (20% by mass) to adjust the pH to 7. Under this weakly alkaline condition, add the diazonium salt solution prepared in step A2 dropwise. After the addition is complete, continue the reaction for 2 hours. When the reaction is complete, adjust the pH of the reaction solution to 5 with dilute hydrochloric acid. The solid precipitates out. Filter the solution and wash the filter cake with water and a small amount of methanol in sequence. Dry the filter cake to obtain the intermediate product. A4. In a four-necked flask, first add 50.7 g of the intermediate product and 150 mL of N,N-dimethylformamide. After stirring evenly, cool the mixture to 0-5°C in an ice-water bath. Slowly add sodium hydroxide solution (40% by mass) until the system becomes strongly alkaline (pH=12). After the addition is complete, remove the ice-water bath and heat to 60°C. Finally, add 34.5 g of thiourea dioxide and react at a constant temperature for 5 hours. After the reaction is complete, cool the reaction solution to room temperature and adjust the pH to 6 with dilute hydrochloric acid. The solid precipitates, is filtered, washed with water until neutral, and dried. The crude product is recrystallized from DMF / water (2:1, volume ratio) to obtain a weather-resistant additive.

[0031] Weigh the following parts by weight of the raw materials for the inner adhesive sublayer: 80 parts thermoplastic vulcanized rubber, 6 parts maleic anhydride-grafted polypropylene, and 0.5 parts antioxidant 1010; Weigh the following raw materials for the outer weather-resistant sublayer: 80 parts thermoplastic vulcanized rubber, 15 parts nano zinc oxide, 3 parts weather-resistant additives, and 1 part zinc stearate; Weigh the following raw materials for the sheath layer: 80 parts thermoplastic vulcanized rubber, 20 parts flame retardant (nano aluminum hydroxide and ammonium polyphosphate compounded in a mass ratio of 4:1), 0.5 parts antioxidant 1010 and 2 parts zinc stearate.

[0032] A method for preparing a highly flexible and environmentally resistant copper-clad aluminum composite aviation cable includes the following steps: Step 1: Multiple annealed copper-clad aluminum wires (copper layer volume ratio of 10%) are layered and twisted in a ceramic-diamond composite guide mold (entry angle of 12°) to form a conductor layer (inner layer twisting pitch L1=10d, outer layer twisting pitch L2=14d). Step 2: Coat the surface of the stranded conductor layer with a silane coupling agent KH-550 (0.05 g / m) and air dry at room temperature to improve the bonding force between the insulation and the conductor. Step 3: Weigh the raw materials of the inner adhesive layer and the outer weather-resistant layer separately, add them to the double-layer co-extrusion extruder, and simultaneously extrude the inner adhesive layer (extrusion temperature of 190℃) and the outer weather-resistant layer (extrusion temperature of 200℃) onto the surface of the conductor layer. Use segmented warm water cooling, with the first segment at 50℃ and the second segment at 30℃. Step 4: Finally, weigh the raw material for the sheath layer, add it to the extruder, and extrude it to coat the surface of the outer weather-resistant layer. Use segmented warm water cooling, with the first segment at 50°C and the second segment at 30°C, to obtain a highly flexible and environmentally resistant copper-clad aluminum composite aviation cable.

[0033] Example 2 Preparation of weather-resistant additives: A1. In a dry three-necked flask, 12.3 g of 3-amino-p-cresol was dissolved in 100 mL of anhydrous N,N-dimethylformamide, followed by the addition of 26.4 g of perfluorovalerate. The mixture was cooled to 0-5 °C in an ice-water bath with stirring. Then, 14.7 g of 1-hydroxybenzotriazole and 20.5 g of EDC·HCl were added sequentially, and stirring was continued for 30 min. N-methylmorpholine was added dropwise to adjust the pH of the reaction solution to 8. The ice bath was removed, and the mixture was heated to room temperature and stirred for 12 h. The reaction was completed. The reaction solution was poured into hydrochloric acid, and a solid precipitated. The solid was filtered, washed with water, and then washed with cold toluene to remove residual DMF. The crude product was recrystallized from ethyl acetate / n-hexane (1:2, volume ratio) to obtain the amidated product. A2. In a four-necked flask, first add 27g of concentrated sulfuric acid (98% by mass) and 70g of water, then add 14.9g of o-nitroaniline while stirring. Cool to 0-5℃ in an ice-water bath, then add 40g of sodium nitrite solution (30% by mass) dropwise. After the addition is complete, continue stirring for 1.5h. Once the reaction is complete, add urea to decompose the residual nitrite, filter to remove residue, and obtain a diazonium salt solution. A3. In a four-necked flask, first add 44.3g of the amidation product and 100mL of N,N-dimethylformamide. After stirring evenly, cool the mixture in an ice-water bath to 0-5℃. Then add sodium hydroxide solution (20% by mass) to adjust the pH to 9. Under this weakly alkaline condition, add the diazonium salt solution prepared in step A2 dropwise. After the addition is complete, continue the reaction for 3 hours. When the reaction is complete, adjust the pH of the reaction solution to 6 with dilute hydrochloric acid. The solid precipitates out. Filter the solution and wash the filter cake successively with water and a small amount of methanol. Dry the filter cake to obtain the intermediate product. A4. In a four-necked flask, first add 50.7 g of the intermediate product and 150 mL of N,N-dimethylformamide. After stirring evenly, cool the mixture to 0-5°C in an ice-water bath. Slowly add sodium hydroxide solution (40% by mass) until the system becomes strongly alkaline (pH=12). After the addition is complete, remove the ice-water bath and heat to 70°C. Finally, add 34.5 g of thiourea dioxide and react at a constant temperature for 6 hours. After the reaction is complete, cool the reaction solution to room temperature and adjust the pH to 7 with dilute hydrochloric acid. The solid precipitates, is filtered, washed with water until neutral, and dried. The crude product is recrystallized from DMF / water (2:1, volume ratio) to obtain a weather-resistant additive.

[0034] Weigh the following parts by weight of the raw materials for the inner adhesive sublayer: 90 parts thermoplastic vulcanized rubber, 7 parts maleic anhydride grafted polypropylene and 0.75 parts antioxidant 1010; Weigh the following raw materials for the outer weather-resistant sublayer: 90 parts thermoplastic vulcanized rubber, 17.5 parts nano zinc oxide, 4.5 parts weather-resistant additives, and 1.5 parts calcium stearate; Weigh the following raw materials for the sheath layer: 90 parts thermoplastic vulcanized rubber, 25 parts flame retardant (nano aluminum hydroxide and ammonium polyphosphate compounded in a mass ratio of 4:1), 0.75 parts antioxidant 1010 and 2.5 parts calcium stearate.

[0035] A method for preparing a highly flexible and environmentally resistant copper-clad aluminum composite aviation cable includes the following steps: Step 1: Multiple annealed copper-clad aluminum wires (copper layer volume ratio of 12.5%) are layered and twisted in a ceramic-diamond composite guide mold (entrance angle of 15°) to form a conductor layer (inner layer twisting pitch L1=12d, outer layer twisting pitch L2=16d). Step 2: Coat the surface of the stranded conductor layer with a silane coupling agent KH-550 (dosage: 0.05-0.1 g / m) and air dry at room temperature to improve the bonding force between the insulation and the conductor. Step 3: Weigh the raw materials of the inner adhesive layer and the outer weather-resistant layer separately, add them to the double-layer co-extrusion extruder, and simultaneously extrude the inner adhesive layer (extrusion temperature of 200℃) and the outer weather-resistant layer (extrusion temperature of 210℃) onto the surface of the conductor layer. Use segmented warm water cooling, with the first segment at 60℃ and the second segment at 40℃. Step 4: Finally, weigh the raw material for the sheath layer, add it to the extruder, and extrude it to coat the surface of the outer weather-resistant layer. Use segmented warm water cooling, with the first segment at 60℃ and the second segment at 40℃, to obtain a highly flexible and environmentally resistant copper-clad aluminum composite aviation cable.

[0036] Example 3 The only difference between this embodiment and Embodiment 2 is that, in this embodiment, the following parts by weight of the raw materials for the inner adhesive sublayer are weighed: 100 parts thermoplastic vulcanized rubber, 8 parts maleic anhydride grafted polypropylene and 1 part antioxidant 1010. Weigh the following raw materials for the outer weather-resistant sublayer: 100 parts thermoplastic vulcanized rubber, 20 parts nano zinc oxide, 6 parts weather-resistant additives, and 2 parts oleamide; Weigh the following raw materials for the sheath layer: 100 parts thermoplastic vulcanized rubber, 30 parts flame retardant (nano aluminum hydroxide and ammonium polyphosphate compounded in a mass ratio of 4:1), 1 part antioxidant 1010 and 3 parts oleamide.

[0037] A method for preparing a highly flexible and environmentally resistant copper-clad aluminum composite aviation cable includes the following steps: Step 1: Multiple annealed copper-clad aluminum wires (copper layer volume ratio of 15%) are layered and twisted in a ceramic-diamond composite guide mold (entry angle of 15°) to form a conductor layer (inner layer twisting pitch L1=12d, outer layer twisting pitch L2=16d). Step 2: Coat the surface of the stranded conductor layer with a silane coupling agent KH-550 (dosage: 0.05-0.1 g / m) and air dry at room temperature to improve the bonding force between the insulation and the conductor. Step 3: Weigh the raw materials of the inner adhesive layer and the outer weather-resistant layer separately, add them to the double-layer co-extrusion extruder, and simultaneously extrude the inner adhesive layer (extrusion temperature of 200℃) and the outer weather-resistant layer (extrusion temperature of 210℃) onto the surface of the conductor layer. Use segmented warm water cooling, with the first segment at 60℃ and the second segment at 40℃. Step 4: Finally, weigh the raw material for the sheath layer, add it to the extruder, and extrude it to coat the surface of the outer weather-resistant layer. Use segmented warm water cooling, with the first segment at 60℃ and the second segment at 40℃, to obtain a highly flexible and environmentally resistant copper-clad aluminum composite aviation cable.

[0038] Comparative Example 1 The difference between this comparative example and Example 3 is that no weather-resistant additives are added in this comparative example to obtain the cable.

[0039] Comparative Example 2 The difference between this comparative example and Comparative Example 1 is that in this comparative example, ordinary copper conductors are used to make cables.

[0040] The cables obtained in Examples 1, 2, and 3, and Comparative Examples 1 and 2, were subjected to the following performance tests: Using the GB / T 33343 standard, the sample is tightly wound around a 5mm diameter round bar and repeatedly bent 180° forward and backward until the wire breaks. The number of times the wire breaks is recorded. The outer weather-resistant layers of Examples 1, 2, 3 and Comparative Example 1 were extruded separately and subjected to the following performance tests: The tensile strength retention rate of the samples after aging for 720 hours was determined using the GB / T 16422.3 standard. The appearance of the samples after 168 hours of salt spray corrosion was observed according to GB / T 10125 standard. The performance test results are shown in Table 1: Table 1

[0041] As can be seen from the performance test results in the table above, the cable produced by the embodiment of the present invention has higher flexibility and environmental resistance than the comparative example. Therefore, the present invention has important application value in the field of aviation cable technology.

[0042] 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 highly flexible and environmentally resistant copper-clad aluminum composite aviation cable, comprising a conductor layer, an inner adhesive sublayer, an outer weather-resistant sublayer, and a sheath layer, characterized in that, The outer weather-resistant sublayer is made of the following raw materials in parts by weight: 80-100 parts thermoplastic vulcanized rubber, 15-20 parts nano zinc oxide, 3-6 parts weather-resistant additives, and 1-2 parts lubricant.

2. The highly flexible and environmentally resistant copper-clad aluminum composite aviation cable according to claim 1, characterized in that, The weather-resistant additive is prepared by the following steps: A1. Dissolve 3-amino-p-cresol in anhydrous N,N-dimethylformamide, then add perfluorovalerate, stir and cool to 0-5℃, add 1-hydroxybenzotriazole and EDC·HCl and stir for 20-30 min, add N-methylmorpholine to adjust the pH of the reaction solution to 8, stir at room temperature for 10-12 h, the reaction is complete, and the amidation product is obtained. A2. In a flask, first add concentrated sulfuric acid and water, then add o-nitroaniline while stirring. Cool to 0-5℃, add sodium nitrite solution dropwise, and continue stirring for 1-1.5 hours after the addition is complete. Once the reaction is complete, a diazonium salt solution is obtained. A3. In a flask, first add the amidation product and N,N-dimethylformamide, stir well, cool to 0-5℃, then add sodium hydroxide solution to adjust the pH to 7-9, add the diazonium salt solution prepared in step A2 dropwise, and continue the reaction for 2-3 hours after the addition is complete. The reaction is then complete, and the intermediate product is obtained. A4. In a flask, first add the intermediate product and N,N-dimethylformamide, stir well, cool to 0-5℃, add sodium hydroxide solution dropwise until the system is strongly alkaline, after the addition is complete, heat to 60-70℃, and finally add thiourea dioxide. React at a constant temperature for 5-6 hours. Once the reaction is complete, the weather-resistant additive is obtained.

3. The highly flexible and environmentally resistant copper-clad aluminum composite aviation cable according to claim 2, characterized in that, In step A1, the ratio of the amounts of 3-amino-p-cresol, perfluorovalerate, 1-hydroxybenzotriazole, and EDC·HCl is 12.3g:26.4g:14.7g:20.5g.

4. The highly flexible and environmentally resistant copper-clad aluminum composite aviation cable according to claim 2, characterized in that, In steps A2 and A3, the ratio of concentrated sulfuric acid, o-nitroaniline, sodium nitrite, and amidation product is 27g:14.9g:40g:44.3g.

5. The highly flexible and environmentally resistant copper-clad aluminum composite aviation cable according to claim 2, characterized in that, In step A4, the ratio of the intermediate product to thiourea dioxide is 50.7g:34.5g.

6. The highly flexible and environmentally resistant copper-clad aluminum composite aviation cable according to claim 1, characterized in that, The conductor layer is formed by stranding multiple annealed copper-clad aluminum monofilaments through layered variable pitch.

7. A highly flexible and environmentally resistant copper-clad aluminum composite aviation cable according to claim 6, characterized in that, In the layered variable pitch stranding, the inner layer stranding pitch L1 = 10-12d, and the outer layer stranding pitch L2 = 14-16d.

8. The highly flexible and environmentally resistant copper-clad aluminum composite aviation cable according to claim 1, characterized in that, The material of the inner adhesive sublayer comprises the following raw materials in parts by weight: 80-100 parts thermoplastic vulcanized rubber, 6-8 parts maleic anhydride-grafted polypropylene, and 0.5-1 parts antioxidant.

9. A highly flexible and environmentally resistant copper-clad aluminum composite aviation cable according to claim 1, characterized in that, The material of the sheath layer includes the following raw materials in parts by weight: 80-100 parts thermoplastic vulcanized rubber, 20-30 parts flame retardant, 0.5-1 part antioxidant and 2-3 parts lubricant.

10. A method for preparing a highly flexible and environmentally resistant copper-clad aluminum composite aviation cable, used to prepare the highly flexible and environmentally resistant copper-clad aluminum composite aviation cable according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Multiple annealed copper-clad aluminum wires are layered and twisted with variable pitch in a mold to form a conductor layer; Step 2: Apply a coupling agent coating to the surface of the stranded conductor layer and air dry at room temperature; Step 3: Weigh the raw materials of the inner adhesive layer and the outer weather-resistant layer separately, add them to the double-layer co-extrusion extruder, and extrude the inner adhesive layer and the outer weather-resistant layer simultaneously onto the surface of the conductor layer, and then cool. Step 4: Finally, weigh the raw material for the sheath layer, add it to the extruder, extrude it to coat the surface of the outer weather-resistant layer, and after cooling, obtain a highly flexible and environmentally resistant copper-clad aluminum composite aviation cable.

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