A deep-sea disposable measuring double-core polyester electromagnetic wire and a preparation method thereof

Abstract

The application provides a deep-sea disposable measuring double-core polyester electromagnetic wire, which has a double-core structure composed of a first bare core (1) and a second bare core (2), the first bare core and the second bare core are arranged in parallel; the first bare core and the second bare core are respectively coated with a polyester insulating paint film (3), and the polyester insulating paint film is further coated with a polyvinyl butyral paint film (4); the first bare core and the second bare core are solid bare copper wire conductors. The polyester insulating paint film and the polyvinyl butyral paint film are used to ensure the salt water resistance of the electromagnetic wire product; the polyvinyl butyral self-adhesive paint is further coated on the outer layer of the polyester insulating paint film to ensure that the insulation performance of the electromagnetic wire product is not damaged after secondary stretching; the double-core structure ensures that the resistance between the two enameled wires is the same, the capacitance is constant, the signal transmission is stable and not easy to be disturbed, and relatively accurate detection information can be obtained in the deep-sea detection process.

Description

Technical Field

[0001] This invention relates to the field of deep-sea exploration technology, and in particular to a disposable double-core polyester electromagnetic wire for deep-sea measurement and its preparation method. Background Technology

[0002] my country's near-shore marine resource exploration technology is becoming increasingly mature, and the exploration of marine resources is receiving unprecedented attention. Near-shore development and deep-sea exploration have become crucial aspects of marine economic development. Because acquiring deep-sea hydrological data is of great significance for future energy development and economic construction, the development of high-precision, high-speed, and highly reliable deep-sea exploration instruments is an inevitable technological development path.

[0003] Disposable deep-sea testing instruments typically consist of a surface receiver and an underwater probe. The underwater probe is launched into the ocean and sinks at a speed of 3–5 meters per second. The data acquisition unit inside the probe collects, processes, and transmits ocean parameters in real time, sending the data as signals to the receiver on the ship via a transmission line within the probe, thus completing the measurement. Currently, the transmission media for the channel include cables and optical fibers. Because wired channels use cables and optical fibers as transmission media, the system is at considerable depths, where the temperature and pressure differences at different depths in the seawater are significant, resulting in high channel wear. The channel uses multi-turn spool winding, which increases the cost of the optical fiber itself, and the fiber cladding is highly susceptible to seawater corrosion, further increasing maintenance costs. The multi-turn spool winding method significantly increases the bending loss of the optical fiber on the signal, and the constantly changing temperature and external forces during the measurement process cause differences in the refractive index of the optical fiber channel at different depths, severely affecting signal stability. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a disposable double-core polyester electromagnetic wire for deep-sea measurement and its preparation method, so as to solve the problem that the existing disposable electromagnetic wires for deep-sea measurement are easily corroded by seawater and have unstable signal transmission during the measurement process.

[0005] To achieve the above and other related objectives, the present invention provides a dual-core polyester electromagnetic wire for deep-sea disposable measurement, characterized in that the dual-core polyester electromagnetic wire for deep-sea disposable measurement has a dual-core structure composed of a first bare core and a second bare core, the first bare core and the second bare core being arranged in parallel; the surfaces of the first bare core and the second bare core are respectively covered with a polyester insulating varnish film, the polyester insulating varnish film being covered with a polyvinyl butyral varnish film; the first bare core and the second bare core are solid bare copper wire conductors.

[0006] The deep-sea disposable dual-core polyester electromagnetic wire of this invention employs a salt-corrosion-resistant polyester insulating varnish coated on the surfaces of the first and second bare cores to ensure the wire's salt-resistance. A polyvinyl butyral self-adhesive varnish is then applied over the polyester insulating varnish to ensure the wire's insulation performance is not compromised after secondary stretching. Simultaneously, the polyvinyl butyral self-adhesive varnish allows the two cores to be combined into a single wire, forming a dual-core structure. This ensures identical resistance and constant capacitance between the two enameled wires, resulting in stable signal transmission that is less susceptible to interference, enabling the acquisition of more accurate detection information during deep-sea exploration.

[0007] Preferably, the first bare core and the second bare core are solid bare copper wire conductors, and the diameter d1 of the solid bare copper wire conductor is 0.125 to 0.135 mm, specifically 0.125 to 0.130 mm or 0.130 to 0.135 mm.

[0008] Preferably, the thickness d2 of the polyester insulating varnish film is 0.010-0.012 mm, specifically 0.010-0.011 mm or 0.011-0.012 mm; and the thickness d3 of the polyvinyl butyral varnish film is 0.006-0.010 mm, specifically 0.006-0.008 mm or 0.008-0.010 mm.

[0009] Preferably, the cross-section of the disposable double-core polyester electromagnetic wire for deep-sea measurement is dumbbell-shaped, and the outer diameter of the major axis D1 of the disposable double-core polyester electromagnetic wire for deep-sea measurement does not exceed 0.315mm, and the outer diameter of the minor axis D2 does not exceed 0.154mm.

[0010] This invention also provides a method for preparing a disposable double-core polyester electromagnetic wire for deep-sea measurement, characterized by comprising the following steps: 1) The copper billet is drawn using a wire drawing die to obtain the first bare core and the second bare core; 2) Annealing is performed on the first and second bare cores; annealing can remove the stress on the surface of the first and second bare cores by high temperature, soften the first and second bare cores, and give them certain elongation properties; 3) The first and second bare cores after annealing are coated with polyester insulating varnish at the same speed along their respective line channels and dried to form a polyester insulating varnish coating layer. 4) Parallelize the first and second bare cores, each coated with a polyester insulating varnish, maintaining a spacing of 6-8 mm between them. Apply a polyvinyl butyral self-adhesive varnish, dry, and form a polyvinyl butyral varnish film. This yields the disposable double-core polyester electromagnetic wire for deep-sea measurements. To ensure the formation of the double-core structure, the spacing between the first and second bare cores during the polyvinyl butyral self-adhesive varnish application must be strictly controlled to 6-8 mm. Within this spacing, the two bare cores can be joined together to form a double-core structure.

[0011] Preferably, in step 1), the wire drawing die is a natural diamond wire drawing die. The natural diamond wire drawing die has a die hole at its center. Along the wire feeding direction, the die hole sequentially includes an inlet area, a lubrication area, a compression area, a sizing area, a decompression area, and an outlet area. The axial cross-sectional angle of the inlet area is 60-80°, the axial cross-sectional angle of the lubrication area is 30-40°, the axial cross-sectional angle of the compression area is 14-18°, the diameter of the sizing area is the same, and the diameter of the decompression area gradually increases from the outlet area.

[0012] In the above-mentioned technical solution of this application, the entrance angle of the die hole of the natural diamond wire drawing die is designed to be 60-80°, which allows the wire to enter the die hole smoothly and avoids being scratched by the edge of the die hole. At the same time, it can bring sufficient lubricant into the compression zone. The lubrication zone angle is designed to be 30-40°, which can store a large amount of lubricant, reduce the loss of tensile force of the wire due to hard pulling, and reduce the occurrence of wire breakage. The compression zone angle is designed to be 14-18°, which allows the metal to undergo stable plastic deformation under compression in the compression zone, avoiding wire damage and breakage caused by severe compression deformation. Through the above structural design, the wire drawing process can be made more stable and smooth, improving the wire drawing efficiency and ensuring the gloss of the surfaces of the first and second bare cores, preparing for the subsequent painting process.

[0013] Preferably, in step 2), the annealing temperature is 480–510°C, specifically 480–590°C, 490–500°C, or 500–510°C, and the annealing time is 3–4 seconds, specifically 3–3.5 seconds or 3.5–4 seconds.

[0014] Preferably, in steps 3) and 4), the paint is applied in multiple cycles, and after each application, it is dried, and this process is repeated. The drying temperature for each drying is 420-500℃, specifically 420-450℃, 450-480℃, or 480-500℃, and the drying time is 2-3 seconds, specifically 2-2.5 seconds or 2.5-3 seconds.

[0015] More preferably, in step 3), the polyester insulating varnish is applied in a 9-cycle coating manner, and in step 3), the polyvinyl butyral self-adhesive varnish is applied in a 4-cycle coating manner.

[0016] Preferably, during the coating process, after each drying, a guide roller is used to transport the first and second bare cores. The diameter of the guide roller gradually decreases from the center to both ends. The guide roller includes a symmetrically arranged first and second bare core support area, and the angle between the support surface of each bare core support area and the horizontal plane is 2-3°. As the number of coatings and drying cycles increases, the support positions of the first and second bare cores shift towards the center of the guide roller.

[0017] In actual production, the first and second bare cores, after being coated, undergo slight elongation due to heat and traction during oven drying. Existing technologies use wire guide rollers with uniform diameters. During the support process, the circumference of the support surface does not increase as the wire elongates, causing the first and second bare cores to bounce. This results in scratches on the surface coating, loss of smoothness, and hinders subsequent coating processes, leading to low product yield. This application creatively reduces the diameter of the wire guide rollers from the center to both ends. As the number of coating and drying cycles increases, the elongation of the first and second bare cores gradually increases. By adjusting the support position towards the center of the wire guide rollers and using a longer support surface, the elongated copper wire is effectively offset, ensuring stable transport of the first and second bare cores during multiple coating and drying processes. This avoids bouncing, ensures a smooth coating, guarantees smooth subsequent coating processes, and improves product yield.

[0018] Preferably, in step 3), the viscosity of the polyester insulating varnish at 25°C is 80–120 mPa·s; in step 4), the viscosity of the polyvinyl butyral self-adhesive varnish at 23°C is 17–25 s.

[0019] As described above, the present invention has the following beneficial effects: (1) The deep-sea disposable double-core polyester electromagnetic wire of the present invention uses polyester insulating varnish and polyvinyl butyral varnish to ensure the salt water resistance of the electromagnetic wire product; polyvinyl butyral self-adhesive varnish is coated on the outer layer of the polyester insulating varnish to ensure that the insulation performance of the electromagnetic wire product is not damaged after secondary stretching; the double-core structure ensures that the resistance between the two enameled wires is the same, the capacitance is constant, the signal transmission is stable and not easily interfered with, and more accurate detection information can be obtained during deep-sea exploration. (2) The preparation process is simple. The use of a specific wire drawing die ensures a more stable and smooth wire drawing process, improves wire drawing efficiency, and ensures the gloss of the first and second bare core surfaces, preparing for the subsequent painting process. The diameter of the wire guide roller gradually decreases from the center to both ends. As the number of coating and drying cycles increases, the elongation of the first and second bare cores gradually increases. By adjusting the support position to shift towards the center of the wire guide roller and using a support surface with a longer circumference, the extended copper wire can be effectively offset, thereby ensuring the stable conveying state of the first and second bare cores during multiple painting and drying processes, avoiding jumping, ensuring a smooth paint film, ensuring the smooth progress of subsequent painting processes, and improving the product qualification rate. Attached Figure Description

[0020] Figure 1 The diagram shows a cross-section of a two-core polyester electromagnetic wire used for deep-sea disposable measurements.

[0021] Figure 2 The diagram shown is a structural schematic of a wire drawing die.

[0022] Figure 3 The diagram shown is a cross-sectional view of the guide roller.

[0023] Figure 4 The diagram shows the manufacturing process of a disposable double-core polyester electromagnetic wire for deep-sea measurements.

[0024] Explanation of reference numerals: 1. First bare core; 2. Second bare core; 3. Polyester insulating varnish film; 4. Polyvinyl butyral varnish film; 5. Die hole; 6. Inlet area along the wire inlet direction; 7. Lubrication area; 8. Compression area; 9. Sizing area; 10. Pressure reduction area; 11. Outlet area; 12. Wire guide roller; 13. First bare core support area; 14. Second bare core support area. Detailed Implementation

[0025] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0026] It should be noted that the process equipment or apparatus not specifically mentioned in the following embodiments are all conventional equipment or apparatus in the art.

[0027] Furthermore, it should be understood that the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, does not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise stated. It should also be understood that the combined connection relationship between one or more devices / apparatus mentioned in this invention does not preclude the existence of other devices / apparatus before or after the combined devices / apparatus, or the insertion of other devices / apparatus between these explicitly mentioned devices / apparatus, unless otherwise stated. Moreover, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or limiting the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0028] Example 1 This embodiment provides a method for preparing a disposable double-core polyester electromagnetic wire for deep-sea measurement, including the following steps: 1) Adopting such Figure 2 The drawing die shown draws copper billets to obtain a first bare core and a second bare core. The drawing die is a natural diamond drawing die, and a die hole 5 is provided at the center of the natural diamond drawing die. Along the wire infeed direction, the die hole sequentially includes an inlet area 6, a lubrication area 7, a compression area 8, a sizing area 9, a decompression area 10, and an outlet area 11. The axial section angle α of the inlet area is 75°, the axial section angle β of the lubrication area is 35°, the axial section angle γ of the compression area is 16°, the diameter of the sizing area is the same, and the diameter gradually increases from the decompression area to the outlet area. 2) Anneal the first and second bare cores; the annealing temperature is 500℃ and the annealing time is 3s; 3) such as Figure 4 As shown, the first bare core (wire #1) and the second bare core (wire #2), after annealing, are coated with polyester insulating varnish at the same speed along their respective routing channels. The viscosity of the polyester insulating varnish at 25°C is 80–120 mPa·s. After drying, a polyester insulating varnish layer is formed. The coating is performed using a multi-cycle coating method, with each coating followed by drying, repeated 9 times. Each drying cycle is performed at 460°C for 3 seconds. During the coating process, after each drying cycle, the following steps are taken: Figure 3 The guide roller 12 shown transports the first and second bare cores. The diameter of the guide roller gradually decreases from the center to both ends. The guide roller includes symmetrically arranged first bare core support areas 13 and second bare core support areas 14. The angle δ between the support surface of each bare core support area and the horizontal plane is 2°. As the number of coating and drying cycles increases, the support positions of the first bare core (line #1) and the second bare core (line #2) shift towards the center of the guide roller. See [reference needed]. Figure 4 The simulated changes in the support position after each painting process; 4) Parallelize the first and second bare cores, each coated with a polyester insulating varnish, maintaining a 7mm distance between them. Apply polyvinyl butyral self-adhesive varnish, which has a viscosity of 17-25s at 23°C. Dry the cores. Repeat this process using multiple coating cycles, drying after each coat, for a total of four cycles. Each drying cycle is at 500°C and lasts for 2 seconds. During the coating process, after each drying cycle, guide rollers 12 are used to transfer the first and second bare cores. The diameter of these guide rollers gradually decreases from the center to both ends. Each guide roller includes symmetrically arranged first and second bare core support areas 13 and 14, with each support surface having an angle δ of 2° with the horizontal plane. As the number of coating and drying cycles increases, the support positions of the first and second bare cores shift towards the center of the guide rollers, forming a polyvinyl butyral varnish film. (See [link to relevant documentation]). Figure 4 By coating four layers of support positions on the middle 1# and 2# lines in parallel, a double-core polyester electromagnetic wire for deep-sea disposable measurement is produced.

[0029] A cross-sectional view of the deep-sea disposable double-core polyester electromagnetic wire for measurement prepared in this embodiment is shown below. Figure 1 As shown, the device has a dual-core structure consisting of a first bare core 1 and a second bare core 2 with a diameter d1 of 0.125 mm, arranged in parallel. The surfaces of the first and second bare cores are respectively covered with a polyester insulating varnish film 3 with a thickness d2 of 0.010 mm, and the polyester insulating varnish film is further covered with a polyvinyl butyral varnish film 4 with a thickness d3 of 0.006 mm. The first and second bare cores are solid bare copper wire conductors. The cross-section of the dual-core polyester electromagnetic wire for deep-sea disposable measurement is dumbbell-shaped, with a major axis outer diameter D1 of 0.302 mm and a minor axis outer diameter D2 of 0.153 mm.

[0030] Example 2 This embodiment provides a method for preparing a disposable double-core polyester electromagnetic wire for deep-sea measurement, including the following steps: 1) Adopting such Figure 2 The drawing die shown draws copper billets to obtain a first bare core and a second bare core. The drawing die is a natural diamond drawing die, and a die hole 5 is provided at the center of the natural diamond drawing die. Along the wire inlet direction, the die hole sequentially includes an inlet area 6, a lubrication area 7, a compression area 8, a sizing area 9, a decompression area 10, and an outlet area 11. The axial section angle α of the inlet area is 60°, the axial section angle β of the lubrication area is 30°, the axial section angle γ of the compression area is 18°, the diameter of the sizing area is the same, and the diameter gradually increases from the decompression area to the outlet area. 2) Anneal the first and second bare cores; the annealing temperature is 480℃ and the annealing time is 4s; 3) such as Figure 4 As shown, the first and second bare cores, after annealing, are coated with polyester insulating varnish at the same speed along their respective travel paths. The viscosity of the polyester insulating varnish at 25°C is 80–120 mPa·s. After drying, a polyester insulating varnish layer is formed. The coating is performed using a multi-cycle coating method, with each coating cycle followed by drying. This process is repeated 9 times after passing through the guide wheel. Each drying cycle is performed at 420°C for 3 seconds. During the coating process, after each drying cycle, the following steps are taken: Figure 3 The guide roller 12 shown transports the first and second bare cores. The diameter of the guide roller gradually decreases from the center to both ends. The guide roller includes a symmetrically arranged first bare core support area 13 and a second bare core support area 14. The angle δ between the support surface of each bare core support area and the horizontal plane is 3°. As the number of coating and drying cycles increases, the support position of the first and second bare cores shifts towards the center of the guide roller. 4) The first and second bare cores, coated with a polyester insulating varnish layer, are laid in parallel lines with a spacing of 6-8 mm between them. A polyvinyl butyral self-adhesive varnish is then applied, with a viscosity of 17-25 s at 23°C. The lines are then dried. This process is repeated four times, using a multi-cycle coating method, with each coating followed by drying. Each drying cycle is performed at 420°C for 2 seconds. During the coating process, after each drying cycle, the first and second bare cores are transferred using a guide roller 12. The diameter of the guide roller gradually decreases from the center to both ends. The guide roller includes symmetrically arranged first and second bare core support areas 13 and 14, with an angle δ of 2° between the support surface of each support area and the horizontal plane. As the number of coating and drying cycles increases, the support positions of the first and second bare cores shift towards the center of the guide roller, forming a polyvinyl butyral varnish film, thus producing a disposable double-core polyester electromagnetic wire for deep-sea measurement.

[0031] A cross-sectional view of the deep-sea disposable double-core polyester electromagnetic wire for measurement prepared in this embodiment is shown below. Figure 1As shown, the device has a dual-core structure consisting of a first bare core 1 and a second bare core 2 with a diameter d1 of 0.135 mm, arranged in parallel. The surfaces of the first and second bare cores are respectively covered with a polyester insulating varnish film 3 with a thickness d2 of 0.012 mm, and the polyester insulating varnish film is further covered with a polyvinyl butyral varnish film 4 with a thickness d3 of 0.010 mm. The first and second bare cores are solid bare copper wire conductors. The cross-section of the dual-core polyester electromagnetic wire for deep-sea disposable measurement is dumbbell-shaped, and the outer diameter of the major axis D1 of the dual-core polyester electromagnetic wire for deep-sea disposable measurement does not exceed 0.315 mm, and the outer diameter of the minor axis D2 does not exceed 0.154 mm.

[0032] Example 3 This embodiment provides a method for preparing a disposable double-core polyester electromagnetic wire for deep-sea measurement, including the following steps: 1) Adopting such Figure 2 The drawing die shown draws copper billets to obtain a first bare core and a second bare core. The drawing die is a natural diamond drawing die, and a die hole 5 is provided at the center of the natural diamond drawing die. Along the wire inlet direction, the die hole sequentially includes an inlet area 6, a lubrication area 7, a compression area 8, a sizing area 9, a decompression area 10, and an outlet area 11. The axial section angle α of the inlet area is 60°, the axial section angle β of the lubrication area is 40°, the axial section angle γ of the compression area is 14°, the diameter of the sizing area is the same, and the diameter gradually increases from the decompression area to the outlet area. 2) Anneal the first and second bare cores; the annealing temperature is 510℃ and the annealing time is 3s; 3) such as Figure 4 As shown, the first and second bare cores, after annealing, are coated with polyester insulating varnish along their respective line channels at the same speed. The viscosity of the polyester insulating varnish at 25°C is 80–120 mPa·s. After drying, a polyester insulating varnish layer is formed. The coating is performed using a multi-cycle coating method, with each coating followed by drying, repeated 9 times. Each drying cycle is performed at 480°C for 2 seconds. During the coating process, after each drying cycle, the following steps are taken: Figure 3 The guide roller 12 shown transports the first and second bare cores. The diameter of the guide roller gradually decreases from the center to both ends. The guide roller includes a symmetrically arranged first bare core support area 13 and a second bare core support area 14. The angle δ between the support surface of each bare core support area and the horizontal plane is 2 to 3°. As the number of coating and drying cycles increases, the support position of the first and second bare cores shifts towards the center of the guide roller. 4. Parallel lines are made of a first bare core and a second bare core coated with a polyester insulating varnish layer, with a spacing of 6-8 mm between them. A polyvinyl butyral self-adhesive varnish is then applied, with a viscosity of 17-25 s at 23°C. The lines are then dried. This process is repeated four times, using a multi-cycle coating method, with each coating followed by drying. Each drying cycle is performed at 460°C for 2 seconds. During the coating process, after each drying cycle, a guide roller 12 is used to transfer the first and second bare cores. The guide roller has a gradually decreasing diameter from its center to both ends. The guide roller includes symmetrically arranged first bare core support areas 13 and second bare core support areas 14, with an angle δ of 2° between the support surface of each support area and the horizontal plane. As the number of coating and drying cycles increases, the support positions of the first and second bare cores shift towards the center of the guide roller, forming a polyvinyl butyral varnish film, thus producing a deep-sea disposable dual-core polyester electromagnetic wire for measurement.

[0033] A cross-sectional view of the deep-sea disposable double-core polyester electromagnetic wire for measurement prepared in this embodiment is shown below. Figure 1 As shown, the device has a dual-core structure consisting of a first bare core 1 and a second bare core 2 with a diameter d1 of 0.125 mm, arranged in parallel. The surfaces of the first and second bare cores are respectively covered with a polyester insulating varnish film 3 with a thickness d2 of 0.010 mm, and the polyester insulating varnish film is further covered with a polyvinyl butyral varnish film 4 with a thickness d3 of 0.006 mm. The first and second bare cores are solid bare copper wire conductors. The cross-section of the dual-core polyester electromagnetic wire for deep-sea disposable measurement is dumbbell-shaped, and the outer diameter of the major axis D1 of the dual-core polyester electromagnetic wire for deep-sea disposable measurement does not exceed 0.315 mm, and the outer diameter of the minor axis D2 does not exceed 0.154 mm.

[0034] The performance of the disposable double-core polyester electromagnetic wires for deep-sea measurement prepared in Examples 1-3 was tested, and the test results are shown in Table 1: Table 1. Test Results Minimum breakdown voltage V 3000 5500 5400 5385 Maximum resistance difference of dual-core wire EUR / M ≤0.012 0.007 0.008 0.006 Minimum elongation ％ ≥20 28 30 29 Continuity of paint film 1 / 30m ≤1 0 0 0 saline pinhole 6 meters ≤0 0 0 0 thermal shock - No cracking at 155℃ for 0.5 hours. OK OK OK Adhesion performance N ≥0.5N 1.2N 1.5N 1.8N The above embodiments are for illustrating the implementation schemes disclosed in this invention and should not be construed as limiting the invention. Furthermore, various modifications listed herein, as well as variations in the methods and compositions of the invention, will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been specifically described in conjunction with various specific preferred embodiments, it should be understood that the invention should not be limited to these specific embodiments. In fact, various modifications as described above that are obvious to those skilled in the art to obtain the invention should be included within the scope of this invention.

Claims

1. A method for preparing a disposable double-core polyester electromagnetic wire for deep-sea measurement, characterized in that: Includes the following steps: 1) The copper billet is drawn using a wire drawing die to obtain the first bare core and the second bare core; 2) Anneal the first and second bare cores; 3) The first and second bare cores after annealing are coated with polyester insulating varnish at the same speed along their respective line channels and dried to form a polyester insulating varnish coating layer. 4) Parallel lines of the first and second bare cores coated with polyester insulating varnish are made, with the distance between them controlled to be 6-8 mm. Polyvinyl butyral self-adhesive varnish is applied and dried to form a polyvinyl butyral varnish film, thus obtaining a disposable double-core polyester electromagnetic wire for deep-sea measurement. In steps 3) and 4), the paint is applied in multiple cycles, and after each coat, it is dried, and this process is repeated. The drying temperature is 420~500℃ and the drying time is 2~3 seconds. During the coating process, after each drying, the first bare core and the second bare core are transported by a guide roller (12). The diameter of the guide roller gradually decreases from the center to both ends. The guide roller includes a first bare core support area (13) and a second bare core support area (14) arranged symmetrically. The angle δ between the support surface of each bare core support area and the horizontal plane is 2~3°. As the number of coatings and drying times increases, the support positions of the first bare core and the second bare core shift towards the center of the guide roller.

2. The preparation method according to claim 1, characterized in that: In step 1), the wire drawing die is a natural diamond wire drawing die. The center of the natural diamond wire drawing die is provided with a die hole (5). Along the wire feeding direction, the die hole includes an inlet area (6), a lubrication area (7), a compression area (8), a sizing area (9), a decompression area (10), and an outlet area (11). The axial section angle α of the inlet area is 60~80°, the axial section angle β of the lubrication area is 30~40°, the axial section angle γ of the compression area is 14~18°, the diameter of the sizing area is the same, and the diameter of the decompression area gradually increases from the outlet area.

3. The preparation method according to claim 1, characterized in that: In step 2), the annealing temperature is 480~510℃ and the annealing time is 3~4s.

4. The preparation method according to claim 1, characterized in that: In step 3), the viscosity of the polyester insulating varnish at 25°C is 80~120 mPa.s; in step 4), the viscosity of the polyvinyl butyral self-adhesive varnish at 23°C is 17~25s.

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