Manufacturing method of polyamide-imide high-heat-resistance enameled wire for new energy automobile

Abstract

The invention discloses a method for manufacturing a polyamide-imide high-heat-resistance enameled wire for a new energy automobile, and the method comprises the following steps: 1), carrying out the surface treatment of a conductor, and improving the surface roughness; 2) preparing insulating paint liquid; (3) coating the insulating paint liquid obtained in the step (2) on the surface of the conductor obtained in the step (1) for multiple times; and 4) carrying out sectional stretching treatment to finally obtain the polyamide-imide high-heat-resistance enameled wire. The polyamide-imide resin, the solvent, the epoxy modifier, the nano composite powder, the silane coupling agent and the dicumyl peroxide are compounded to prepare the insulating paint liquid, and the insulating paint liquid is coated on the conductor for multiple times, so that a compact layer can be formed on the conductor, and the insulating paint liquid has the advantages of high heat resistance, high thermal stability, high mechanical property and the like; the extreme requirements of the new energy automobile driving motor on high temperature resistance, high-frequency pulse voltage resistance and refrigerant corrosion resistance of the enameled wire are met, the manufacturing steps are simple, and the enameled wire is suitable for industrial popularization and application.

Description

Technical Field

[0001] The present invention belongs to the technical field of enameled wires, and in particular relates to a method for manufacturing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles. Background Art

[0002] The drive motor of new energy vehicles is one of the core components of new energy vehicles, and enameled wire is the key raw material of the drive motor. As new energy vehicles rapidly develop towards high power density, high voltage platform and long endurance, the drive motor enameled wire faces extreme working conditions challenges.

[0003] Traditional polyimide enameled wire has a long-term operating temperature range of ≤200°C. At temperatures of 220°C or above, the paint film decomposes and adhesion plummets, posing a risk of short circuits. Furthermore, traditional polyimide enameled wire lacks both heat resistance and flexibility, leaving significant room for improvement. 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 method for preparing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles.

[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 producing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles comprises the following steps:

[0007] 1) Surface treatment of the conductor to improve surface roughness;

[0008] 2) preparing insulating varnish liquid;

[0009] 3) applying the insulating varnish obtained in step 2) to the surface of the conductor obtained in step 1) in multiple layers;

[0010] 4) performing a segmented stretching treatment to finally obtain the desired polyamide-imide high-heat-resistant enameled wire for new energy vehicles.

[0011] Furthermore, in step 1), the step of surface treating the conductor includes:

[0012] The conductor is sequentially subjected to alkaline washing, acid washing, and ultrasonic cleaning, and then plasma etching to control the surface roughness to no more than 1 μm.

[0013] Furthermore, in step 2), the raw materials for preparing the insulating varnish liquid include the following components in parts by weight:

[0014] 40-70 parts of polyamide-imide resin

[0015] 75-100 parts solvent

[0016] 2-6 parts epoxy modifier

[0017] 0.5-5 parts of nanocomposite powder

[0018] 1-4 parts of silane coupling agent

[0019] 0.1-3 parts of dicumyl peroxide.

[0020] Furthermore, the nano-composite powder is compounded by nano-aluminum nitride and nano-silicon carbide, and has a particle size of 40-80 nm.

[0021] Furthermore, the insulating varnish liquid is prepared by the following steps:

[0022] By weight, 0.5-5 parts of nanocomposite powder and 1-4 parts of silane coupling agent are mixed, and then 75-100 parts of solvent, 40-70 parts of polyamide-imide resin, 2-6 parts of epoxy modifier and 0.1-3 parts of dicumyl peroxide are added, and the mixture is evenly dispersed at a speed of 2500-3000 rpm under vacuum conditions to obtain the desired insulating paint liquid.

[0023] Furthermore, in step 3), the conductor is preheated to 190-230°C, and the insulating varnish liquid is coated using a four-coat four-bake process. After the first three coatings, the conductor is cured at 370-430°C for 30-60s, and after the last coating, the conductor is cured at 480-550°C for 120-200s.

[0024] Furthermore, the coating thicknesses from the first to the fourth times are 30-33 μm, 25-28 μm, 20-23 μm, and 15-18 μm, respectively.

[0025] Furthermore, in step 4), the step of performing the segmented stretching treatment includes:

[0026] The steel sheet is first stretched at a temperature of 260-300° C. at a rate of 4-8 m / min, and then stretched at a temperature of 150-200° C. at a rate of 12-15 m / min, with the total stretching deformation controlled at 0.8-1.3%.

[0027] The present invention also discloses a polyamide-imide high-heat-resistant enameled wire for new energy vehicles prepared by a method for preparing the polyamide-imide high-heat-resistant enameled wire for new energy vehicles.

[0028] Furthermore, the polyamide-imide high-heat-resistant enameled wire for new energy vehicles includes a conductor, the surface of which is coated with insulating varnish liquid using a four-coating and four-baking process, and the insulating varnish liquid is prepared by polyamide-imide resin, solvent, epoxy modifier, nano-composite powder, silane coupling agent and diisopropylbenzene peroxide.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention discloses a method for producing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles. The method comprises the following steps: preparing an insulating varnish liquid by compounding a polyamide-imide resin, a solvent, an epoxy modifier, a nano-composite powder, a silane coupling agent and dicumyl peroxide, and applying the liquid to a conductor in multiple layers, thereby forming a dense layer on the conductor. The method has the advantages of high heat resistance, high thermal stability, good flexibility, high mechanical properties, and the like, and meets the extreme requirements of new energy vehicle drive motors for the enameled wire's high-temperature resistance, high-frequency pulse voltage resistance, and refrigerant corrosion resistance. The method also has simple production steps and is suitable for industrial promotion and use. DETAILED DESCRIPTION

[0031] 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.

[0032] 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.

[0033] In one aspect, the present invention discloses a method for producing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles, comprising the following steps:

[0034] 1) Surface treatment of the conductor to improve surface roughness;

[0035] 2) preparing insulating varnish liquid;

[0036] 3) applying the insulating varnish obtained in step 2) to the surface of the conductor obtained in step 1) in multiple layers;

[0037] 4) performing a segmented stretching treatment to finally obtain the desired polyamide-imide high-heat-resistant enameled wire for new energy vehicles.

[0038] In step 1), the step of surface treating the conductor includes:

[0039] The conductor is sequentially subjected to alkaline washing, acid washing, and ultrasonic cleaning, followed by plasma etching, to control the surface roughness to no more than 1 μm. This operation can improve the adhesion between the conductor and the insulating paint liquid.

[0040] In step 2), the raw materials for preparing the insulating paint liquid include the following components in parts by weight:

[0041] 40-70 parts of polyamide-imide resin

[0042] 75-100 parts solvent

[0043] 2-6 parts epoxy modifier

[0044] 0.5-5 parts of nanocomposite powder

[0045] 1-4 parts of silane coupling agent

[0046] 0.1-3 parts of dicumyl peroxide.

[0047] The insulating varnish liquid is prepared by the following steps:

[0048] By weight, 0.5-5 parts of nanocomposite powder and 1-4 parts of silane coupling agent are mixed, and then 75-100 parts of solvent, 40-70 parts of polyamide-imide resin, 2-6 parts of epoxy modifier and 0.1-3 parts of dicumyl peroxide are added, and the mixture is evenly dispersed at a speed of 2500-3000 rpm under vacuum conditions to obtain the desired insulating paint liquid.

[0049] Nano-composite powder is compounded by nano-aluminum nitride and nano-silicon carbide, with a particle size of 40-80nm. Nano-aluminum nitride has high thermal conductivity, and nano-silicon carbide has high hardness, high wear resistance and corona resistance. Nano-aluminum nitride and nano-silicon carbide synergistically improve the heat resistance of the product. After being treated with a silane coupling agent, it is not easy to agglomerate, and at the same time, the compatibility with other raw materials is improved. The silane coupling agent is used to bridge the nano-composite powder and the polyamide-imide resin, combined with the rough structure of the conductor surface, to improve the adhesion of the insulating paint liquid.

[0050] Epoxy modifiers contain siloxane structures and are prepared by modifying siloxane-modified epoxy resins with silane coupling agents. When combined with polyamide-imide resins and nanocomposite powders, these modifiers can improve the product's thermal stability, flexibility, and interfacial bonding, while reducing brittleness. The epoxy groups in the epoxy modifiers react with the terminal carboxyl and amino groups in the polyamide-imide resins to form a covalently crosslinked network. The siloxane segments then hydrolyze and condense to form an inorganic-organic hybrid structure.

[0051] Dicumyl peroxide can decompose at high temperatures above 150°C to generate free radicals, which trigger crosslinking (CC bond formation) between resin molecular chains and grafting reactions between epoxy modifiers and resins, thereby increasing the crosslinking density and improving the heat resistance and mechanical strength of the product.

[0052] The solvent includes 30-50 parts of N-methylpyrrolidone and 35-70 parts of xylene. N-methylpyrrolidone can fully dissolve the polyamide-imide resin. Xylene is volatile and forms a dense layer through gradient volatilization during coating.

[0053] In step 3), the conductor is preheated to 190-230°C, and the insulating varnish liquid is applied using a four-coating and four-baking process. After the first three coatings, the conductor is cured at 370-430°C for 30-60s, and after the last coating, the conductor is cured at a high temperature of 480-550°C for 120-200s. The coating thicknesses from the first to the fourth coating are 30-33μm, 25-28μm, 20-23μm, and 15-18μm, respectively. A dense layer is formed by gradient curing, which improves the thermal stability of the dense layer and avoids cracking at high temperatures. The decreasing coating thickness is conducive to eliminating pinhole defects and increasing the breakdown voltage.

[0054] In step 4), the step of performing the segmented stretching treatment includes:

[0055] The process is first stretched at a temperature of 260-300°C at a rate of 4-8 m / min, and then at a temperature of 150-200°C at a rate of 12-15 m / min, with the total deformation controlled at 0.8-1.3%. This segmented stretching matches the thermal expansion coefficients of the conductor and the dense layer, preventing accidents such as cracking caused by hot and cold cycles.

[0056] On the other hand, the present invention also discloses a method for preparing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles. The prepared polyamide-imide high-heat-resistant enameled wire includes a conductor, and the surface of the conductor is coated with an insulating varnish liquid using a four-coating and four-baking process. The insulating varnish liquid is prepared from polyamide-imide resin, solvent, epoxy modifier, nano-composite powder, silane coupling agent and dicumyl peroxide.

[0057] Example 1

[0058] A method for producing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles comprises the following steps:

[0059] 1) Surface treatment of copper conductor to improve surface roughness;

[0060] 2) preparing insulating varnish liquid;

[0061] 3) applying the insulating varnish obtained in step 2) on the surface of the copper conductor obtained in step 1) four times;

[0062] 4) performing a segmented stretching treatment to finally obtain the desired polyamide-imide high-heat-resistant enameled wire for new energy vehicles.

[0063] In step 1), the step of surface treating the copper conductor includes:

[0064] The copper conductor is sequentially subjected to alkaline washing, acid washing, and ultrasonic cleaning, followed by plasma etching to control the surface roughness to about 0.8 μm.

[0065] In step 2), the raw materials for preparing the insulating paint liquid include the following components in parts by weight:

[0066] 40 parts of polyamide-imide resin

[0067] 90 parts solvent

[0068] 6 parts epoxy modifier

[0069] 5 parts of nanocomposite powder

[0070] 4 parts of silane coupling agent

[0071] 3 parts of dicumyl peroxide.

[0072] The insulating varnish liquid is prepared by the following steps:

[0073] By weight, 5 parts of nanocomposite powder and 4 parts of silane coupling agent are mixed, and then 90 parts of solvent, 40 parts of polyamide-imide resin, 6 parts of epoxy modifier and 3 parts of dicumyl peroxide are added. The mixture is evenly dispersed at a rate of 3000 rpm under vacuum conditions to obtain the desired insulating paint liquid.

[0074] The nanocomposite powder is prepared by compounding nano-aluminum nitride and nano-silicon carbide in a mass ratio of 1:1, and has a particle size of 40nm.

[0075] The solvent included 50 parts of N-methylpyrrolidone and 40 parts of xylene.

[0076] In step 3), the copper conductor is preheated to 200°C and coated with insulating varnish using a four-coat, four-bake process. The first three coats are cured at 400°C for 40 seconds, and the final coat is cured at 500°C for 180 seconds. The first, second, and fourth coats have thicknesses of 30 μm, 25 μm, 20 μm, and 15 μm, respectively.

[0077] In step 4), the step of performing the segmented stretching treatment includes:

[0078] The film is first stretched at a temperature of 280° C. at a rate of 4 m / min, and then stretched at a temperature of 200° C. at a rate of 15 m / min, with the total stretching deformation controlled at about 0.8%.

[0079] This embodiment also discloses a method for preparing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles. The prepared polyamide-imide high-heat-resistant enameled wire includes a conductor. The surface of the conductor is coated with an insulating varnish using a four-coating and four-baking process. The insulating varnish is prepared from a polyamide-imide resin, a solvent, an epoxy modifier, a nano-composite powder, a silane coupling agent, and dicumyl peroxide.

[0080] Example 2

[0081] A method for producing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles comprises the following steps:

[0082] 1) Surface treatment of the conductor to improve surface roughness;

[0083] 2) preparing insulating varnish liquid;

[0084] 3) applying the insulating varnish obtained in step 2) to the surface of the conductor obtained in step 1) in multiple layers;

[0085] 4) performing a segmented stretching treatment to finally obtain the desired polyamide-imide high-heat-resistant enameled wire for new energy vehicles.

[0086] In step 1), the step of surface treating the conductor includes:

[0087] The conductor is sequentially subjected to alkaline washing, acid washing, and ultrasonic cleaning, followed by plasma etching to control the surface roughness to 1μm. This operation can improve the adhesion between the conductor and the insulating paint liquid.

[0088] In step 2), the raw materials for preparing the insulating paint liquid include the following components in parts by weight:

[0089] 70 parts of polyamide-imide resin

[0090] 75 parts solvent

[0091] 2 parts epoxy modifier

[0092] 0.5 parts of nanocomposite powder

[0093] 1 part silane coupling agent

[0094] 0.1 parts of dicumyl peroxide.

[0095] The insulating varnish liquid is prepared by the following steps:

[0096] By weight, 0.5 parts of nanocomposite powder and 1 part of silane coupling agent were mixed, and then 75 parts of solvent, 70 parts of polyamide-imide resin, 2 parts of epoxy modifier, and 0.1 part of dicumyl peroxide were added. The mixture was evenly dispersed at a rate of 2500 rpm under vacuum conditions to obtain the desired insulating paint liquid.

[0097] Nano-composite powder is made by compounding nano-aluminum nitride and nano-silicon carbide with a particle size of 80nm. Nano-aluminum nitride has high thermal conductivity, and nano-silicon carbide has high hardness, high wear resistance and corona resistance. After being treated with a silane coupling agent, it is not easy to agglomerate, which facilitates bonding with polyamide-imide resin and improves compatibility with other raw materials.

[0098] The solvent includes 40 parts of N-methylpyrrolidone and 35 parts of xylene. N-methylpyrrolidone can fully dissolve the polyamide-imide resin. Xylene is volatile and forms a dense layer through gradient volatilization during coating.

[0099] In step 3), the conductor is preheated to 230° C. and coated with insulating varnish using a four-coat, four-bake process. The first three coats are cured at 430° C. for 30 seconds, and the last coat is cured at 550° C. for 120 seconds.

[0100] The coating thicknesses for the first to fourth times were 33 μm, 28 μm, 23 μm, and 18 μm, respectively.

[0101] In step 4), the step of performing the segmented stretching treatment includes:

[0102] The steel sheet was first stretched at a temperature of 260° C. at a rate of 4 m / min, and then stretched at a temperature of 150° C. at a rate of 12 m / min, with the total stretching deformation controlled at 1.3%.

[0103] The rest is the same as Example 1.

[0104] Example 3

[0105] A method for producing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles comprises the following steps:

[0106] 1) Surface treatment of the conductor to improve surface roughness;

[0107] 2) preparing insulating varnish liquid;

[0108] 3) applying the insulating varnish obtained in step 2) to the surface of the conductor obtained in step 1) in multiple layers;

[0109] 4) performing a segmented stretching treatment to finally obtain the desired polyamide-imide high-heat-resistant enameled wire for new energy vehicles.

[0110] In step 1), the step of surface treating the conductor includes:

[0111] The conductor is sequentially subjected to alkaline washing, acid washing, and ultrasonic cleaning, followed by plasma etching to control the surface roughness to 1μm. This operation can improve the adhesion between the conductor and the insulating paint liquid.

[0112] In step 2), the raw materials for preparing the insulating paint liquid include the following components in parts by weight:

[0113] 60 parts of polyamide-imide resin

[0114] 80 parts solvent

[0115] 3 parts epoxy modifier

[0116] 1 part of nanocomposite powder

[0117] 2 parts of silane coupling agent

[0118] 1 part of dicumyl peroxide.

[0119] The insulating varnish liquid is prepared by the following steps:

[0120] By weight, 1 part of nanocomposite powder is mixed with 2 parts of silane coupling agent, and then 80 parts of solvent, 60 parts of polyamide-imide resin, 3 parts of epoxy modifier and 1 part of dicumyl peroxide are added. The mixture is evenly dispersed at a rate of 2800 rpm under vacuum conditions to obtain the desired insulating paint liquid.

[0121] Nano-composite powder is made by compounding nano-aluminum nitride and nano-silicon carbide with a particle size of 50nm. Nano-aluminum nitride has high thermal conductivity, and nano-silicon carbide has high hardness, high wear resistance and corona resistance. After being treated with silane coupling agent, it is not easy to agglomerate, which facilitates bonding with polyamide-imide resin and improves compatibility with other raw materials.

[0122] Epoxy modifiers contain siloxane structures and are prepared by modifying siloxane-modified epoxy resins with silane coupling agents. When combined with polyamide-imide resins and nanocomposite powders, these modifiers can improve the product's thermal stability, flexibility, and interfacial bonding, while reducing brittleness. The epoxy groups in the epoxy modifiers react with the terminal carboxyl and amino groups in the polyamide-imide resins to form a covalently crosslinked network. The siloxane segments then hydrolyze and condense to form an inorganic-organic hybrid structure.

[0123] Dicumyl peroxide can decompose at high temperatures above 150°C to generate free radicals, which trigger crosslinking (CC bond formation) between resin molecular chains and grafting reactions between epoxy modifiers and resins, thereby increasing the crosslinking density and improving the heat resistance and mechanical strength of the product.

[0124] The solvent includes 40 parts of N-methylpyrrolidone and 40 parts of xylene. N-methylpyrrolidone can fully dissolve the polyamide-imide resin. Xylene is volatile and forms a dense layer through gradient volatilization during coating.

[0125] In step 3), the conductor is preheated to 200°C and coated with insulating varnish using a four-coat, four-bake process. The first three coats are cured at 380°C for 60s, and the last coat is cured at 480°C for 200s.

[0126] The coating thicknesses for the first to fourth times were 30 μm, 26 μm, 20 μm, and 17 μm, respectively.

[0127] In step 4), the step of performing the segmented stretching treatment includes:

[0128] The steel sheet was first stretched at a rate of 4 m / min at a temperature of 300°C, and then stretched at a rate of 15 m / min at a temperature of 200°C. The total stretching deformation was controlled at 1.3%.

[0129] The rest is the same as Example 1.

[0130] 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.

[0131] 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 polyamide-imide high-heat-resistant enameled wire for new energy vehicles, characterized in that: The following steps are involved: 1) Surface treatment of the conductor to improve surface roughness; 2) preparing insulating varnish liquid; 3) applying the insulating varnish obtained in step 2) to the surface of the conductor obtained in step 1) in multiple layers; 4) performing a segmented stretching treatment to finally obtain the desired polyamide-imide high-heat-resistant enameled wire for new energy vehicles.

2. The method for producing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles according to claim 1, characterized in that: In step 1), the step of surface treating the conductor includes: The conductor is sequentially subjected to alkaline washing, acid washing, and ultrasonic cleaning, and then plasma etching to control the surface roughness to no more than 1 μm.

3. The method for producing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles according to claim 1, characterized in that: In step 2), the raw materials for preparing the insulating varnish liquid include the following components in parts by weight: 40-70 parts of polyamide-imide resin 75-100 parts solvent 2-6 parts epoxy modifier 0.5-5 parts of nanocomposite powder 1-4 parts of silane coupling agent 0.1-3 parts of dicumyl peroxide.

4. The method for producing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles according to claim 3, characterized in that: The nano composite powder is prepared by compounding nano aluminum nitride and nano silicon carbide, and has a particle size of 40-80 nm.

5. The method for producing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles according to claim 3, characterized in that: The insulating varnish liquid is prepared by the following steps: By weight, 0.5-5 parts of nanocomposite powder and 1-4 parts of silane coupling agent are mixed, and then 75-100 parts of solvent, 40-70 parts of polyamide-imide resin, 2-6 parts of epoxy modifier and 0.1-3 parts of dicumyl peroxide are added, and the mixture is evenly dispersed at a speed of 2500-3000 rpm under vacuum conditions to obtain the desired insulating paint liquid.

6. The method for producing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles according to claim 1, characterized in that: In step 3), the conductor is preheated to 190-230°C and coated with insulating varnish using a four-coat, four-bake process. The first three coatings are cured at 370-430°C for 30-60s, and the last coating is cured at 480-550°C for 120-200s.

7. The method for producing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles according to claim 6, characterized in that: The coating thicknesses for the first to fourth times are 30-33 μm, 25-28 μm, 20-23 μm, and 15-18 μm, respectively.

8. The method for producing a polyamide-imide high-heat-resistant enameled wire for new energy vehicles according to claim 1, characterized in that: In step 4), the step of performing the segmented stretching treatment includes: The steel sheet is first stretched at a temperature of 260-300° C. at a rate of 4-8 m / min, and then stretched at a temperature of 150-200° C. at a rate of 12-15 m / min, with the total stretching deformation controlled at 0.8-1.3%.

9. A polyamideimide high heat-resistant enameled wire for new energy vehicles prepared by the method for preparing a polyamideimide high heat-resistant enameled wire for new energy vehicles according to any one of claims 1 to 8.

10. The polyamide-imide high heat-resistant enameled wire for new energy vehicles according to claim 9, characterized in that: The polyamide-imide high-heat-resistant enameled wire for new energy vehicles includes a conductor, the surface of which is coated with an insulating varnish using a four-coating and four-baking process. The insulating varnish is prepared from a polyamide-imide resin, a solvent, an epoxy modifier, a nanocomposite powder, a silane coupling agent, and dicumyl peroxide.