High-frequency-resistant polyurethane enameled wire and manufacturing method thereof

Abstract

The invention discloses a high-frequency-resistant polyurethane enameled wire and a manufacturing method thereof. The manufacturing method comprises the following steps: pretreating a conductive core wire; preparing insulating paint liquid; coating the insulating paint liquid on the conductive core wire by adopting a three-stage gradient coating mode; and performing high-frequency pulse aging treatment to obtain the required high-frequency-resistant polyurethane enameled wire. Polyurethane, nano boron nitride, carboxylated ferrite micro powder, an epoxy modified organic silicon toughening agent and graphene are compounded, the conductive core wire is coated with the compound in a three-stage gradient coating mode, and the three-stage coating mode is beneficial for achieving densification of a paint layer and improving the interface bonding force; the low dielectric constant of the nano boron nitride and the electromagnetic shielding effect of the carboxylated ferrite micro powder are utilized to synergistically reduce high-frequency polarization loss, the low dielectric constant characteristic of the organic silicon is utilized to inhibit the polarization loss of a molecular chain segment under high frequency, and the attenuation efficiency of electromagnetic waves is optimized, so that the high-frequency-resistant polyurethane enameled wire can be obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of enameled wires, and in particular relates to a high-frequency resistant polyurethane enameled wire and a manufacturing method thereof. Background Art

[0002] Enameled wire is a type of electromagnetic wire with excellent insulation properties, made of a metal conductor coated with an insulating varnish. It is currently widely used in motors, transformers, electronic components, and other fields. The performance of enameled wire directly affects the operating efficiency and safety of electrical equipment. Wire enamel must possess excellent adhesion to the metal conductor, ensuring a tight bond and preventing hollowing, damage, or even shedding of the enamel layer.

[0003] Based on this, the present invention discloses a high-frequency resistant polyurethane enameled wire and a manufacturing method thereof. Summary of the Invention

[0004] In order to solve the technical problems existing in the prior art, the purpose of the present invention is to provide a high-frequency resistant polyurethane enameled wire and a manufacturing method thereof.

[0005] In order to achieve the above-mentioned purpose and the above-mentioned technical effect, the technical solution adopted by the present invention is:

[0006] A method for manufacturing a high-frequency resistant polyurethane enameled wire comprises the following steps:

[0007] 1) Pre-treat the conductive core wire;

[0008] 2) preparing insulating varnish liquid;

[0009] 3) applying the insulating varnish obtained in step 2) to the conductive core wire obtained in step 1) using a three-stage gradient coating method;

[0010] 4) subjecting the product obtained in step 3) to a high-frequency pulse aging treatment to obtain the desired high-frequency resistant polyurethane enameled wire;

[0011] There is no particular order for steps 1) and 2).

[0012] Furthermore, the method further comprises step 5): coating the outer surface of the high-frequency resistant polyurethane enameled wire obtained in step 4) with a fluorinated polyimide protective layer, wherein the thickness of the fluorinated polyimide protective layer is controlled to be 3-7 μm.

[0013] Furthermore, in step 1), the step of pre-treating the conductive core wire includes:

[0014] The conductive core wire is first subjected to annealing treatment, the annealing temperature is controlled at 400-650°C, the annealing time is controlled at 10-35 minutes, and then the surface of the conductive core wire is subjected to nano-oxide layer deposition treatment.

[0015] Furthermore, the nano-oxide layer includes an aluminum oxide layer and / or a magnesium oxide layer, and the thickness is controlled to be 60-140 nm.

[0016] Furthermore, the nano-oxide layer includes an aluminum oxide layer and a magnesium oxide layer, the thickness ratio of the aluminum oxide layer to the magnesium oxide layer is 2-3:1, the aluminum oxide layer is first deposited on the surface of the conductive core wire, and then the magnesium oxide layer is deposited on the surface of the aluminum oxide layer.

[0017] Furthermore, in step 2), the insulating paint liquid includes the following components in parts by weight:

[0018] 80-100 parts polyurethane

[0019] 5-15 parts of nano boron nitride

[0020] 1-10 parts of carboxylated ferrite powder

[0021] 3-10 parts epoxy modified silicone toughening agent

[0022] 1-5 parts of graphene.

[0023] Furthermore, the particle size D50 of the carboxylated ferrite powder is 0.8-1.5 μm.

[0024] Furthermore, in step 3), the step of applying the insulating varnish obtained in step 2) to the conductive core wire obtained in step 1) by a three-level gradient coating method comprises:

[0025] First-stage coating: The viscosity of the insulating paint liquid is 17-22 Pa·s, and the curing temperature is 225-245°C;

[0026] Second-stage coating: The viscosity of the insulating paint liquid is 10-12 Pa·s, and the curing temperature is 240-275°C;

[0027] Third-level coating: The viscosity of the insulating paint liquid is 6-9 Pa·s and the curing temperature is 285-310℃;

[0028] After each coating, the eccentricity of the paint layer is checked online to be ≤3%.

[0029] Furthermore, in step 4), the high-frequency pulse aging process parameters are:

[0030] The applied frequency is controlled at 2-10 MHz, the field strength is controlled at 60-100 kV / mm, the alternating electric field, and the processing time is controlled at 5-20 min.

[0031] The invention also discloses a high-frequency resistant polyurethane enameled wire manufactured by the manufacturing method of the high-frequency resistant polyurethane enameled wire.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The invention discloses a high-frequency resistant polyurethane enameled wire and a manufacturing method thereof. Polyurethane is compounded with nano-boron nitride, carboxylated ferrite powder, epoxy-modified organic silicon toughening agent and graphene, and coated on a conductive core wire through a three-stage gradient coating method. The three-stage coating method is conducive to achieving densification of the paint layer and improving interface bonding strength. The isocyanate groups in the polyurethane can react with the hydroxyl groups on the surface of the nano-boron nitride, and the unreacted nano-boron nitride part can be combined with the polyurethane through van der Waals force. The polar groups (such as amino groups) in the polyurethane can react with the carboxyl groups in the carboxylated ferrite powder. The graphene can interact with the aromatic chain segments of the polyurethane. The isocyanate groups in the polyurethane can react with the epoxy-modified organic silicon toughening agent. The epoxy groups in the toughening agent react, and the silicone chain segments can be entangled with the polyurethane, which is beneficial to improving the flexibility, heat resistance and interfacial bonding strength of the paint layer, reducing the risk of brittle fracture, avoiding peeling of the paint layer and the conductive core wire, and avoiding hollowing, breakage or even falling off of the paint layer. At the same time, the low dielectric constant of nano-boron nitride and the electromagnetic shielding effect of carboxylated ferrite powder are used to synergistically reduce high-frequency polarization loss, and the low dielectric constant characteristics of silicone are used to suppress the polarization loss of molecular chain segments at high frequencies, optimizing the electromagnetic wave attenuation performance, thereby obtaining a high-frequency resistant polyurethane enameled wire with a dielectric loss factor tanδ≤0.002, a breakdown voltage ≥8kV, an adhesion ≥25N, and a refrigerant-resistant insulation resistance change rate ≤5%. DETAILED DESCRIPTION

[0034] The present invention is described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0035] The following is a brief summary of one or more aspects to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceivable aspects and is neither intended to identify key or critical elements of all aspects nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that will be provided later.

[0036] The present invention discloses a method for manufacturing a high-frequency resistant polyurethane enameled wire, comprising the following steps:

[0037] 1) Pre-treat the conductive core wire;

[0038] 2) preparing insulating varnish liquid;

[0039] 3) applying the insulating varnish obtained in step 2) to the conductive core wire obtained in step 1) using a three-stage gradient coating method;

[0040] 4) subjecting the product obtained in step 3) to a high-frequency pulse aging treatment to obtain the desired high-frequency resistant polyurethane enameled wire;

[0041] There is no particular order for steps 1) and 2).

[0042] In some embodiments, the method for producing a high-frequency-resistant polyurethane enameled wire further includes step 5): coating the outer surface of the high-frequency-resistant polyurethane enameled wire obtained in step 4) with a fluorinated polyimide protective layer, wherein the thickness of the fluorinated polyimide protective layer is controlled to be 3-7 μm. Step 5) may be included or excluded based on actual needs.

[0043] In some embodiments, in step 1), the step of pre-treating the conductive core wire includes:

[0044] The conductive core wire is first subjected to annealing treatment, the annealing temperature is controlled at 400-650°C, the annealing time is controlled at 10-35 minutes, and then the surface of the conductive core wire is subjected to nano-oxide layer deposition treatment.

[0045] In some specific embodiments, the nano-oxide layer includes an aluminum oxide layer and / or a magnesium oxide layer, and the thickness is controlled to be 60-140 nm.

[0046] In some more specific embodiments, the nano-oxide layer includes an aluminum oxide layer and a magnesium oxide layer, and the thickness ratio of the aluminum oxide layer to the magnesium oxide layer is 2-3:1. The aluminum oxide layer is first deposited on the surface of the conductive core wire, and then the magnesium oxide layer is deposited on the surface of the aluminum oxide layer.

[0047] In some more specific embodiments, the nano-oxide layer includes an aluminum oxide layer and a magnesium oxide layer, and the thickness ratio of the aluminum oxide layer to the magnesium oxide layer is 2-3:1. The magnesium oxide layer is first deposited on the surface of the conductive core wire, and then the aluminum oxide layer is deposited on the surface of the magnesium oxide layer.

[0048] In some embodiments, in step 2), the insulating paint liquid includes the following components in parts by weight:

[0049] 80-100 parts polyurethane

[0050] 5-15 parts of nano boron nitride

[0051] 1-10 parts of carboxylated ferrite powder

[0052] 3-10 parts epoxy modified silicone toughening agent

[0053] 1-5 parts of graphene.

[0054] In some embodiments, the particle size D50 of the carboxylated ferrite powder is 0.8-1.5 μm, and the carboxylated ferrite powder is prepared by modifying the ferrite powder with concentrated nitric acid.

[0055] In some embodiments, the insulating varnish liquid is prepared by the following steps:

[0056] The method comprises the following steps: adding 5-15 parts by weight of nano-boron nitride to a solvent prepared by compounding xylene and cyclohexanone in a volume ratio of 1:1; then adding 1-10 parts of carboxylated ferrite micropowder and 1-5 parts of graphene; and ultrasonically dispersing the mixture at 600-800W for 20-60 minutes to form a uniform suspension; adding 80-100 parts of polyurethane to the uniform suspension; and stirring the mixture at 20-40°C and 900-1200rpm for 30-50 minutes; slowly adding 3-10 parts of epoxy-modified organic silicon toughening agent dropwise, continuing stirring for 10-25 minutes, and adjusting the solid content to 20-40%; and finally vacuum degassing at -0.08 to -0.1MPa for 30-50 minutes, and filtering the mixture through a 200-mesh filter to obtain the desired insulating paint liquid.

[0057] In some embodiments, in step 3), the step of applying the insulating varnish obtained in step 2) to the conductive core wire obtained in step 1) using a three-stage gradient coating method comprises:

[0058] First-stage coating: The viscosity of the insulating paint liquid is 17-22 Pa·s, and the curing temperature is 225-245°C;

[0059] Second-stage coating: The viscosity of the insulating paint liquid is 10-12 Pa·s, and the curing temperature is 240-275°C;

[0060] Third-level coating: The viscosity of the insulating paint liquid is 6-9 Pa·s and the curing temperature is 285-310℃;

[0061] After each coating, the eccentricity of the paint layer is checked online to be ≤3%.

[0062] In some embodiments, in step 4), the high-frequency pulse aging process parameters are:

[0063] The applied frequency is controlled at 2-10 MHz, the field strength is controlled at 60-100 kV / mm, the alternating electric field, and the processing time is controlled at 5-20 min.

[0064] The present invention also discloses a high-frequency resistant polyurethane enameled wire produced by the above-mentioned method for producing the high-frequency resistant polyurethane enameled wire, comprising a conductive core wire and an insulating varnish liquid coated thereon, with a dielectric loss factor tanδ≤0.002, a breakdown voltage≥8kV, an adhesion force≥25N, and a refrigerant-resistant insulation resistance change rate≤5%.

[0065] Example 1

[0066] A method for manufacturing a high-frequency resistant polyurethane enameled wire comprises the following steps:

[0067] 1) Pre-treat the conductive core wire;

[0068] 2) preparing insulating varnish liquid;

[0069] 3) applying the insulating varnish obtained in step 2) to the conductive core wire obtained in step 1) using a three-stage gradient coating method;

[0070] 4) subjecting the product obtained in step 3) to a high-frequency pulse aging treatment to obtain the desired high-frequency resistant polyurethane enameled wire;

[0071] 5) The outer surface of the high-frequency resistant polyurethane enameled wire obtained in step 4) is coated with a fluorinated polyimide protective layer, wherein the thickness of the fluorinated polyimide protective layer is 5 μm.

[0072] In step 1), the step of pre-treating the conductive core wire includes:

[0073] The conductive core wire is first annealed, the annealing temperature is controlled at 500°C, and the annealing time is controlled at 20 minutes. Then, a nano-aluminum oxide layer is deposited on the surface of the conductive core wire with a thickness of 80 nm.

[0074] In step 2), the insulating paint liquid includes the following components in parts by weight:

[0075] 100 parts polyurethane

[0076] 5 parts of nano boron nitride

[0077] 8 parts of carboxylated ferrite powder

[0078] 10 parts of epoxy modified silicone toughening agent

[0079] 2 parts of graphene.

[0080] The particle size D50 of the carboxylated ferrite powder is 0.8 μm, and the carboxylated ferrite powder is prepared by modifying the ferrite powder with concentrated nitric acid.

[0081] The insulating varnish liquid is prepared by the following steps:

[0082] In parts by weight, 5 parts of nano-boron nitride are added to a solvent prepared by compounding xylene and cyclohexanone in a volume ratio of 1:1, and then 8 parts of carboxylated ferrite powder and 2 parts of graphene are added, and ultrasonic dispersion is carried out at 700W for 50 minutes to form a uniform suspension; then 100 parts of polyurethane are added to the uniform suspension, and the mixture is stirred at 30°C and 1000 rpm for 40 minutes; then 10 parts of epoxy-modified silicone toughening agent are slowly added dropwise, and stirring is continued for 25 minutes, and the solid content is adjusted to 30%; finally, vacuum degassing is carried out at -0.08MPa for 50 minutes, and then filtering is carried out with a 200-mesh filter to obtain the required insulating paint liquid.

[0083] In step 3), the step of applying the insulating varnish obtained in step 2) to the conductive core wire obtained in step 1) by a three-level gradient coating method comprises:

[0084] First-stage coating: The viscosity of the insulating paint liquid is 18 Pa·s and the curing temperature is 245°C;

[0085] Second-stage coating: The viscosity of the insulating paint liquid is 11 Pa·s and the curing temperature is 275°C;

[0086] Third-level coating: The viscosity of the insulating paint liquid is 7 Pa·s and the curing temperature is 285°C;

[0087] After each coating, the eccentricity of the paint layer is checked online to be ≤3%.

[0088] In step 4), the high-frequency pulse aging process parameters are:

[0089] The applied frequency was 5 MHz, the field strength was 60 kV / mm, and the AC electric field was processed for 10 min.

[0090] This embodiment also discloses a high-frequency resistant polyurethane enameled wire manufactured by the manufacturing method of the high-frequency resistant polyurethane enameled wire as described above, comprising a conductive core wire and an insulating varnish liquid coated thereon.

[0091] Example 2

[0092] A method for manufacturing a high-frequency resistant polyurethane enameled wire comprises the following steps:

[0093] 1) Pre-treat the conductive core wire;

[0094] 2) preparing insulating varnish liquid;

[0095] 3) applying the insulating varnish obtained in step 2) to the conductive core wire obtained in step 1) using a three-stage gradient coating method;

[0096] 4) The product obtained in step 3) is subjected to high-frequency pulse aging treatment to obtain the desired high-frequency resistant polyurethane enameled wire.

[0097] In step 1), the step of pre-treating the conductive core wire includes:

[0098] The conductive core wire is first annealed, the annealing temperature is controlled at 450°C, the annealing time is controlled at 25 minutes, and then the surface of the conductive core wire is subjected to nano-oxide layer deposition treatment, and the thickness is controlled at 90nm.

[0099] The nano-oxide layer includes an aluminum oxide layer and a magnesium oxide layer, and the thickness ratio of the aluminum oxide layer to the magnesium oxide layer is 2:1. The aluminum oxide layer is first deposited on the surface of the conductive core wire, and then the magnesium oxide layer is deposited on the surface of the aluminum oxide layer.

[0100] In step 2), the insulating paint liquid includes the following components in parts by weight:

[0101] 80 parts polyurethane

[0102] 15 parts of nano boron nitride

[0103] 10 parts of carboxylated ferrite powder

[0104] 10 parts of epoxy modified silicone toughening agent

[0105] 5 parts of graphene.

[0106] The particle size D50 of the carboxylated ferrite powder is 1.5 μm, and the carboxylated ferrite powder is prepared by modifying the ferrite powder with concentrated nitric acid.

[0107] The insulating varnish liquid is prepared by the following steps:

[0108] By weight, 15 parts of nano-boron nitride are added to a solvent prepared by compounding xylene and cyclohexanone in a volume ratio of 1:1, and then 10 parts of carboxylated ferrite powder and 5 parts of graphene are added, and ultrasonic dispersion is carried out at 800W for 50 minutes to form a uniform suspension; then 80 parts of polyurethane are added to the uniform suspension, and the mixture is stirred at 40°C and 1200 rpm for 30 minutes; then 10 parts of epoxy-modified silicone toughening agent are slowly added dropwise, and stirring is continued for 25 minutes, and the solid content is adjusted to 40%; finally, vacuum degassing is carried out at -0.1MPa for 50 minutes, and then filtering is carried out with a 200-mesh filter to obtain the required insulating paint liquid.

[0109] In step 3), the step of applying the insulating varnish obtained in step 2) to the conductive core wire obtained in step 1) by a three-level gradient coating method comprises:

[0110] First-stage coating: The viscosity of the insulating paint liquid is 22 Pa·s and the curing temperature is 225°C;

[0111] Second-stage coating: The viscosity of the insulating paint liquid is 12 Pa·s and the curing temperature is 240°C;

[0112] Third-level coating: The viscosity of the insulating paint liquid is 9 Pa·s and the curing temperature is 310°C;

[0113] After each coating, the eccentricity of the paint layer is checked online to be ≤3%.

[0114] In step 4), the high-frequency pulse aging process parameters are:

[0115] The applied frequency was controlled at 10 MHz, the field strength was controlled at 100 kV / mm, the AC electric field, and the processing time was controlled at 5 min.

[0116] This embodiment also discloses a high-frequency resistant polyurethane enameled wire manufactured by the manufacturing method of the high-frequency resistant polyurethane enameled wire as described above, comprising a conductive core wire and an insulating varnish liquid coated thereon.

[0117] The rest is the same as in Example 1.

[0118] Example 3

[0119] A method for manufacturing a high-frequency resistant polyurethane enameled wire comprises the following steps:

[0120] 1) Pre-treat the conductive core wire;

[0121] 2) preparing insulating varnish liquid;

[0122] 3) applying the insulating varnish obtained in step 2) to the conductive core wire obtained in step 1) using a three-stage gradient coating method;

[0123] 4) subjecting the product obtained in step 3) to a high-frequency pulse aging treatment to obtain the desired high-frequency resistant polyurethane enameled wire;

[0124] 5): A fluorinated polyimide protective layer is coated on the outer surface of the high-frequency resistant polyurethane enameled wire obtained in step 4), and the thickness of the fluorinated polyimide protective layer is controlled to be 7 μm.

[0125] In step 1), the step of pre-treating the conductive core wire includes:

[0126] The conductive core wire is first annealed, the annealing temperature is controlled at 500°C, the annealing time is controlled at 35 minutes, and then the surface of the conductive core wire is deposited with a nano-oxide layer, and the thickness is controlled at 120nm.

[0127] The nano-oxide layer includes an aluminum oxide layer and a magnesium oxide layer, and the thickness ratio of the aluminum oxide layer to the magnesium oxide layer is 2:1. The aluminum oxide layer is first deposited on the surface of the conductive core wire, and then the magnesium oxide layer is deposited on the surface of the aluminum oxide layer.

[0128] In step 2), the insulating paint liquid includes the following components in parts by weight:

[0129] 90 parts polyurethane

[0130] 10 parts of nano boron nitride

[0131] 1 part of carboxylated ferrite powder

[0132] 3 parts epoxy modified silicone toughening agent

[0133] 1 part graphene.

[0134] The particle size D50 of the carboxylated ferrite powder is 1.5 μm, and the carboxylated ferrite powder is prepared by modifying the ferrite powder with concentrated nitric acid.

[0135] The insulating varnish liquid is prepared by the following steps:

[0136] In parts by weight, 10 parts of nano-boron nitride are added to a solvent prepared by compounding xylene and cyclohexanone in a volume ratio of 1:1, and then 1 part of carboxylated ferrite powder and 1 part of graphene are added, and ultrasonic dispersion is carried out at 700W for 60 minutes to form a uniform suspension; then 90 parts of polyurethane are added to the uniform suspension, and the mixture is stirred at 25°C and 1200rpm for 30 minutes; then 3 parts of epoxy-modified silicone toughening agent are slowly added dropwise, and stirring is continued for 25 minutes, and the solid content is adjusted to 20%; finally, vacuum degassing is carried out at -0.08MPa for 40 minutes, and then filtering is carried out with a 200-mesh filter to obtain the required insulating paint liquid.

[0137] In step 3), the step of applying the insulating varnish obtained in step 2) to the conductive core wire obtained in step 1) by a three-level gradient coating method comprises:

[0138] First-stage coating: The viscosity of the insulating paint liquid is 20 Pa·s and the curing temperature is 230°C;

[0139] Second-stage coating: The viscosity of the insulating paint liquid is 11 Pa·s and the curing temperature is 250°C;

[0140] Third-level coating: The viscosity of the insulating paint liquid is 7 Pa·s and the curing temperature is 300°C;

[0141] After each coating, the eccentricity of the paint layer is checked online to be ≤3%.

[0142] In some embodiments, in step 4), the high-frequency pulse aging process parameters are:

[0143] The applied frequency was controlled at 7 MHz, the field strength was controlled at 90 kV / mm, the AC electric field, and the processing time was controlled at 18 min.

[0144] This embodiment also discloses a high-frequency resistant polyurethane enameled wire manufactured by the manufacturing method of the high-frequency resistant polyurethane enameled wire as described above, comprising a conductive core wire and an insulating varnish liquid coated thereon.

[0145] The rest is the same as in Example 1.

[0146] The high-frequency resistant polyurethane enameled wire obtained in Example 1 was subjected to performance testing. The results showed that the dielectric loss factor tanδ was 0.001, the breakdown voltage was 8 kV, the adhesion was 30 N, and the refrigerant resistance insulation resistance change rate was 3%.

[0147] Parts or structures not specifically described in the present invention may adopt existing technologies or existing products and will not be described in detail here.

[0148] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for producing a high-frequency resistant polyurethane enameled wire, characterized in that: The following steps are involved: 1) Pre-treat the conductive core wire; 2) preparing insulating varnish liquid; 3) applying the insulating varnish obtained in step 2) to the conductive core wire obtained in step 1) using a three-stage gradient coating method; 4) subjecting the product obtained in step 3) to a high-frequency pulse aging treatment to obtain the desired high-frequency resistant polyurethane enameled wire; There is no particular order for steps 1) and 2).

2. The method for manufacturing a high-frequency resistant polyurethane enameled wire according to claim 1, characterized in that: The method further comprises the step 5): coating the outer surface of the high-frequency resistant polyurethane enameled wire obtained in step 4) with a fluorinated polyimide protective layer, wherein the thickness of the fluorinated polyimide protective layer is controlled to be 3-7 μm.

3. The method for manufacturing a high-frequency resistant polyurethane enameled wire according to claim 1, characterized in that: In step 1), the step of pre-treating the conductive core wire includes: The conductive core wire is first subjected to annealing treatment, the annealing temperature is controlled at 400-650°C, the annealing time is controlled at 10-35 minutes, and then the surface of the conductive core wire is subjected to nano-oxide layer deposition treatment.

4. The method for manufacturing a high-frequency resistant polyurethane enameled wire according to claim 3, characterized in that: The nano-oxide layer includes an aluminum oxide layer and / or a magnesium oxide layer, and the thickness is controlled to be 60-140 nm.

5. The method for manufacturing a high-frequency resistant polyurethane enameled wire according to claim 4, characterized in that: The nano-oxide layer includes an aluminum oxide layer and a magnesium oxide layer, and the thickness ratio of the aluminum oxide layer to the magnesium oxide layer is 2-3:

1. The aluminum oxide layer is first deposited on the surface of the conductive core wire, and then the magnesium oxide layer is deposited on the surface of the aluminum oxide layer.

6. The method for manufacturing a high-frequency resistant polyurethane enameled wire according to claim 1, characterized in that: In step 2), the insulating varnish liquid includes the following components in parts by weight: 80-100 parts polyurethane 5-15 parts of nano boron nitride 1-10 parts of carboxylated ferrite powder 3-10 parts epoxy modified silicone toughening agent 1-5 parts of graphene.

7. The method for manufacturing a high-frequency resistant polyurethane enameled wire according to claim 6, characterized in that: The particle size D50 of the carboxylated ferrite powder is 0.8-1.5 μm.

8. The method for manufacturing a high-frequency resistant polyurethane enameled wire according to claim 1, characterized in that: In step 3), the step of applying the insulating varnish obtained in step 2) to the conductive core wire obtained in step 1) by a three-level gradient coating method comprises: First-stage coating: The viscosity of the insulating paint liquid is 17-22 Pa·s, and the curing temperature is 225-245°C; Second-stage coating: The viscosity of the insulating paint liquid is 10-12 Pa·s, and the curing temperature is 240-275°C; Third-level coating: The viscosity of the insulating paint liquid is 6-9 Pa·s and the curing temperature is 285-310℃; After each coating, the eccentricity of the paint layer is checked online to be ≤3%.

9. The method for manufacturing a high-frequency resistant polyurethane enameled wire according to claim 1, characterized in that: In step 4), the high-frequency pulse aging process parameters are: The applied frequency is controlled at 2-10 MHz, the field strength is controlled at 60-100 kV / mm, the alternating electric field, and the processing time is controlled at 5-20 min.

10. A high-frequency resistant polyurethane enameled wire manufactured by the manufacturing method of high-frequency resistant polyurethane enameled wire according to any one of claims 1 to 9.