Insulated wire and preparation method thereof, coil and electronic / electrical device

Abstract

This invention discloses an insulated wire, its preparation method, a coil, and electronic / electrical equipment, relating to the field of insulated wire technology. The wire includes a conductor and a bottom layer and an outer layer sequentially disposed around the conductor, the bottom layer and the outer layer together serving as the insulation layer of the insulated wire. The bottom layer is made of phenolphthalein-based polyaryletherketone (PEEK). The outer layer is obtained by blending and granulating at least two of PEEK, thermoplastic polyimide, and phenolphthalein-based PEEK. The insulated wire provided by this invention incorporates a PEK-C layer as a bottom layer between the outer insulation layer and the metal conductor, which improves the adhesion between PEEK and copper, reducing the risk of detachment and breakage. Simultaneously, the incorporation of TPI into the PEEK of the outer insulation layer improves the overall adhesion of the insulation layer to the metal and ensures that the insulation layer maintains good insulation performance at high temperatures.

Description

Technical Field

[0001] The present invention relates to the technical field of insulated wires, and more particularly to an insulated wire and a preparation method thereof, a coil and an electronic / electrical device. Background Art

[0002] At present, in the field of new energy vehicles, 800V high-voltage drive systems have become the first choice for new energy vehicles due to their efficient charging capabilities and excellent endurance performance. However, with the increase in voltage levels, the requirements for insulation materials have become more stringent. In high-voltage and high-temperature working environments, insulated wires must maintain their excellent insulation properties to ensure the safe and reliable operation of electrical systems.

[0003] In the prior art, polyetheretherketone (PEEK) is a resin with excellent electrical insulation performance, and its volume resistivity is about 10 15 -10 16 Ω·cm, it still has a low dielectric constant and small dielectric loss in the high frequency range. For example, at room temperature, 4 The dielectric constant at Hz is 3.2, and the dielectric loss is only 0.02. At the same time, this PEEK resin also has excellent heat resistance and mechanical properties as well as excellent chemical stability and excellent resistance to hot water and steam. Therefore, PEEK resin is an ideal insulation material for magnet wire.

[0004] However, PEEK resin is too resistant to chemical solvents and is insoluble in general organic solvents. It cannot be prepared into a coating for coating electromagnetic wires and can only be coated on the electromagnetic wires by high-temperature melt extrusion. However, the high melt viscosity and fast cooling rate of PEEK resin result in unstable adhesion between the PEEK resin coating and the copper surface of the electromagnetic wire, which often poses the risk of tube detachment and breakage. On the other hand, the dielectric constant of PEEK resin in an environment above 200°C will increase with the increase of operating temperature, resulting in a decrease in its insulation performance. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a new insulated wire to solve the problem in the prior art that the PEEK resin of the insulated wire has low adhesion with the conductor and the insulation performance decreases at high temperature.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] An insulated wire comprises a conductor, and a bottom layer and an outer insulating layer sequentially arranged on the periphery of the conductor, wherein the material of the bottom layer is phenolphthalein-based polyaryl etherketone (PEK-C for short);

[0008] The material of the outer insulating layer is obtained by blending and granulating at least two of polyetheretherketone (PEEK), thermoplastic polyimide (TPI), and phenolphthalein polyaryletherketone (PEK-C).

[0009] In the present invention, the bottom layer and the outer insulating layer are used together as the insulating layer of the insulated wire; PEK-C is used as the bottom layer of the insulated wire, which can effectively improve the adhesion between PEEK and the conductor (copper); at the same time, TPI and PEEK are mixed into the outer insulating layer, that is, the outer insulating layer, and TPI can reduce the thermal expansion coefficient of the outer insulating layer, which can further improve the adhesion with the conductor metal. At the same time, TPI has a lower dielectric constant at high temperature, which can improve the breakdown resistance of the insulated wire, ensure its insulation performance under high temperature and high pressure conditions, and can reduce the thickness of the insulating layer to a certain extent.

[0010] Furthermore, along a single-side direction outward from the conductor, the total thickness of the bottom layer and the outer insulating layer is 50-300 μm.

[0011] Furthermore, along the one-side direction outward from the conductor, the thickness of the bottom layer is 5-10 μm.

[0012] Furthermore, the structure of the phenolphthalein polyaryletherketone has a repeating unit as shown in the following formula 1:

[0013]

[0014] Formula 1.

[0015] The phenolphthalein polyaryletherketone can be a conventional commercially available product, such as the phenolphthalein polyaryletherketone (Mw is about 52,000) produced by Xuzhou Engineering Plastics Factory of Changchun Institute of Applied Chemistry, Chinese Academy of Sciences.

[0016] In addition, the present invention also obtains PEK-C by laboratory synthesis. Phenolphthalein and dichlorobenzophenone are added to a mixed solution of DMAC and ethylbenzene in an equivalent ratio, and the temperature is gradually increased from 150 to 200° C. under alkaline catalytic conditions for 2 hours. After the reaction, the viscosity of the system is about 1.1 dL / g, and the weight average molecular weight Mw of the product is about 50,000.

[0017] PEEK and TPI are both commercially available conventional extrusion materials.

[0018] Furthermore, the outer insulating layer is obtained by blending and granulating polyetheretherketone and thermoplastic polyimide, wherein the mass ratio of the thermoplastic polyimide is 10-90%, and preferably, the mass ratio of the thermoplastic polyimide is 40-90%.

[0019] Furthermore, the outer insulating layer is obtained by blending and granulating three resins of polyetheretherketone, thermoplastic polyimide and phenolphthalein polyaryletherketone, wherein the mass ratio of phenolphthalein polyaryletherketone is 2~10%, and the mass ratio of the thermoplastic polyimide is 10~90%; preferably, the mass ratio of the phenolphthalein polyaryletherketone is 2~10%, and the mass ratio of the thermoplastic polyimide is 40~90%.

[0020] A second object of the present invention is to provide a method for preparing an insulated wire, comprising the following steps:

[0021] (1) Preparation of blend: The resin required for the outer insulating layer is blended through a twin-screw extruder at 400-420°C to form a uniform mixing system, and after cooling, it is granulated through a pelletizer to form the particle polymer material required for the outer insulating layer;

[0022] (2) Insulated wire processing: The resin material of the bottom layer is heated to a molten state, and coated on the surface of the preheated conductor to obtain a core wire; then the particle polymer material prepared in step (1) is heated to a molten state, coated on the core wire, and cooled to obtain an insulated wire.

[0023] A third object of the present invention is to provide a coil composed of the above-mentioned insulated wire.

[0024] The present invention also aims to provide an electrical or electronic device prepared from the coil.

[0025] The present invention also aims to provide a co-extrusion die for processing the insulated wire, the die comprising a die core, a conductor delivery channel being formed through the center of the die core, a first flow channel and a second flow channel being formed in an annular shape and concentrically arranged along the outer periphery of the conductor delivery channel in sequence, the longitudinal cross-sections of the first flow channel and the second flow channel being trumpet-shaped, comprising an inclined flow channel section and a horizontal section parallel to the conductor delivery channel, the conductor of the insulated wire being delivered from the front end to the rear end of the die core via the conductor delivery channel, the resin material of the bottom layer in a molten state flows in via the inclined section of the first flow channel, then flows out via the horizontal section of the first flow channel, and is coated on the outer periphery of the conductor to form the bottom layer of the insulated wire; at the same time, the resin material of the outer insulating layer in a molten state flows in via the inclined section of the second flow channel, then flows out via the horizontal section of the second flow channel, and is coated on the outer periphery of the bottom layer to form the outer insulating layer of the insulated wire, and the insulated wire is formed after cooling.

[0026] The mold for processing insulated wires provided by the present invention can form a bottom layer and an outer insulating layer on a conductor at the same time without preheating the conductor multiple times, thereby improving production and processing efficiency.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] The insulated wire provided by the present invention adds a PEK-C layer as a bottom layer between the outer insulating layer and the metal conductor, which can improve the adhesion between PEEK and copper and reduce the risk of tube detachment and breakage; at the same time, TPI is mixed into the outer insulating layer PEEK, which can improve the overall adhesion of the insulating layer to the metal on the one hand, and can also ensure that the insulating layer still has good insulation performance under high temperature conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural diagram of a mold used for processing an insulated wire in the present invention.

[0030] Figure 2 It is a schematic diagram of the side cross-sectional structure of the insulated wire in the present invention.

[0031] In the figure,

[0032] 1. Mold core; 2. Conductor conveying channel; 3. First flow channel; 4. Second flow channel; 5. Inclined section; 6. Horizontal section.

[0033] 10. Conductor; 20. Bottom layer; 30. Outer insulation layer. DETAILED DESCRIPTION

[0034] Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar modifications without violating the connotation of the present invention, so the present invention is not limited to the specific implementation disclosed below.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0036] like Figure 1 and Figure 2As shown, the present invention provides a mold for processing an insulated wire, which includes a mold core 1, a conductor conveying channel 2 is formed through the center of the mold core 1, and a first flow channel 3 and a second flow channel 4 are formed in an annular shape and concentrically arranged along the outer periphery of the conductor conveying channel 2 in sequence. The longitudinal cross-sections of the first flow channel 3 and the second flow channel 4 are trumpet-shaped, including an inclined section 5 and a horizontal section 6 parallel to the conductor conveying channel 2. The conductor 10 of the insulated wire is conveyed from the front end to the rear end of the mold core 1 through the conductor conveying channel 2. The resin material of the bottom layer in a molten state flows in through the inclined section of the first flow channel 3, and then flows out through the horizontal section of the first flow channel 3, and is coated on the outer periphery of the conductor 10 to form a bottom layer 20 of the insulated wire; at the same time, the resin material of the outer insulating layer in a molten state flows in through the inclined section of the second flow channel 4, and then flows out through the horizontal section of the second flow channel 4, and is coated on the outer periphery of the bottom layer 20 to form an outer insulating layer 30 of the insulated wire, and the insulated wire is formed after cooling.

[0037] Specifically, when the outer insulating layer is a blend of PEEK and TPI, PEEK and TPI are blended at 370-420° C. through a twin-screw extruder to form a uniform mixing system, and then granulated into a particle polymer material through a pelletizer after cooling.

[0038] When the outer insulating layer is a blend of PEEK, PEK-C and TPI, PEEK, PEK-C and TPI are mixed according to the mass proportions: PEK-C accounts for 2-10%, PEEK and TPI account for (8%-90%), PEEK and PEK-C account for (10%-90%), and then blended through a twin-screw extruder at 370-420°C to form a uniform mixing system, and then granulated by a pelletizer after cooling to become a particle polymer material.

[0039] Example 1 (conductor size is 1.50 x 2.20 mm)

[0040] This embodiment provides an insulated wire, which can be prepared by using the mold and method provided above, and includes a metal conductor copper and an insulating layer wrapped around the outer periphery of the copper, wherein the insulating layer includes two layers, namely a bottom layer and an outer insulating layer;

[0041] The bottom layer in contact with the conductor is phenolphthalein polyaryletherketone, and its structure contains repeating units as shown in the following formula 1:

[0042]

[0043] Formula 1;

[0044] The material of the outer insulating layer is obtained by blending and granulating polyetheretherketone (PEEK) and thermoplastic polyimide (TPI). In this embodiment, the mass proportion of PEEK is 90%, the mass proportion of TPI is 10%, the thickness of the bottom layer is 10μm, and the thickness of the outer insulating layer is 160μm, that is, the total thickness of the insulating layer is 170μm.

[0045] Example 2

[0046] In this embodiment, the only difference from Embodiment 1 is that, in the outer insulating layer, the mass proportion of PEEK is 80%, the mass proportion of TPI is 20%, and the thickness of the outer insulating layer is 120 μm, that is, the total thickness of the insulating layer is 130 μm.

[0047] Example 3

[0048] In this embodiment, the only difference from Embodiment 1 is that, in the outer insulating layer, the mass proportion of PEEK is 70%, the mass proportion of TPI is 30%, and the thickness of the outer insulating layer is 180 μm, that is, the total thickness of the insulating layer is 190 μm.

[0049] Example 4

[0050] The only difference between this embodiment and Embodiment 1 is that, in the outer insulating layer, the mass proportion of PEEK is 60%, and the mass proportion of TPI is 40%.

[0051] Example 5

[0052] The only difference between this embodiment and Embodiment 1 is that, in the outer insulating layer, the mass proportion of PEEK is 50%, and the mass proportion of TPI is 50%.

[0053] Example 6

[0054] The only difference between this embodiment and Embodiment 1 is that, in the outer insulating layer, the mass proportion of PEEK is 40%, and the mass proportion of TPI is 60%.

[0055] Example 7

[0056] The only difference between this embodiment and Embodiment 1 is that, in the outer insulating layer, the mass proportion of PEEK is 30%, and the mass proportion of TPI is 70%.

[0057] Example 8

[0058] The only difference between this embodiment and Embodiment 1 is that, in the outer insulating layer, the mass proportion of PEEK is 20%, and the mass proportion of TPI is 80%.

[0059] Example 9

[0060] The only difference between this embodiment and Embodiment 1 is that, in the outer insulating layer, the mass proportion of PEEK is 10%, and the mass proportion of TPI is 90%.

[0061] Example 10

[0062] In this embodiment, the only difference from Embodiment 1 is that, in the outer insulating layer, the mass proportion of PEEK is 88%, the mass proportion of PEK-C is 2%, and the mass proportion of TPI is 10%.

[0063] Embodiment 11

[0064] In this embodiment, the only difference from Embodiment 2 is that, in the outer insulating layer, the mass proportion of PEEK is 77%, the mass proportion of PEK-C is 3%, and the mass proportion of TPI is 20%.

[0065] Example 12

[0066] The only difference from Example 3 in this embodiment is that in the outer insulating layer, the mass proportion of PEEK is 66%, the mass proportion of PEK-C is 4%, and the mass proportion of TPI is 30%.

[0067] Example 13

[0068] In this embodiment, the only difference from Embodiment 4 is that, in the outer insulating layer, the mass proportion of PEEK is 55%, the mass proportion of PEK-C is 5%, and the mass proportion of TPI is 40%.

[0069] Embodiment 14

[0070] In this embodiment, the only difference from Embodiment 5 is that, in the outer insulating layer, the mass proportion of PEEK is 44%, the mass proportion of PEK-C is 6%, and the mass proportion of TPI is 50%.

[0071] Embodiment 15

[0072] In this embodiment, the only difference from Embodiment 6 is that, in the outer insulating layer, the mass proportion of PEEK is 33%, the mass proportion of PEK-C is 7%, and the mass proportion of TPI is 60%.

[0073] Example 16

[0074] The only difference between this embodiment and Embodiment 7 is that, in the outer insulating layer, the mass proportion of PEEK is 22%, the mass proportion of PEK-C is 8%, and the mass proportion of TPI is 70%.

[0075] Embodiment 17

[0076] In this embodiment, the only difference from Embodiment 8 is that, in the outer insulating layer, the mass proportion of PEEK is 10%, the mass proportion of PEK-C is 10%, and the mass proportion of TPI is 80%.

[0077] Embodiment 18

[0078] The only difference from Example 9 in this embodiment is that in the outer insulating layer, the mass proportion of PEEK is 1%, the mass proportion of PEK-C is 9%, and the mass proportion of TPI is 90%.

[0079] Comparative Example 1

[0080] The only difference between this embodiment and Embodiment 1 is that, in the outer insulating layer, the mass proportion of PEEK is 95%, and the mass proportion of TPI is 5%.

[0081] Comparative Example 2

[0082] The only difference between this embodiment and Embodiment 1 is that, in the outer insulating layer, the mass proportion of PEEK is 5%, and the mass proportion of TPI is 95%.

[0083] Comparative Example 3

[0084] The present embodiment is different from the embodiment 1 only in that the mass proportion of PEEK in the outer insulating layer is 100%.

[0085] Comparative Example 4

[0086] The only difference between this embodiment and Embodiment 1 is that the mass proportion of TPI in the outer insulating layer is 100%.

[0087] Comparative Example 5

[0088] The present embodiment is different from the embodiment 1 only in that no bottom layer is provided.

[0089] Comparative Example 6

[0090] In this embodiment, compared with Embodiment 1, the only difference is that the material of the bottom layer is replaced with PEEK in equal amount.

[0091] Comparative Example 7

[0092] The present embodiment is different from the embodiment 4 only in that the thickness of the bottom layer is 15 μm and the thickness of the outer insulating layer is 155 μm.

[0093] Comparative Example 8

[0094] In this embodiment, the only difference from Embodiment 10 is that, in the outer insulating layer, the mass proportion of PEEK is 98%, and the mass proportion of PEK-C is 2%.

[0095] Comparative Example 9

[0096] The present embodiment is different from the embodiment 10 only in that no bottom layer is provided.

[0097] Performance Testing

[0098] The following tests were performed on the insulated wires prepared in Examples 1-18 and Comparative Examples 1-10:

[0099] 1. Adhesion test

[0100] The adhesion test method provided by IEC-60851-3 2019 Test Method 8 is used for testing. The specific steps are as follows:

[0101] Take 300 mm of the insulated wire obtained in the embodiment and the comparative example as a sample, cut a circle of the sample in the middle position until the conductor, and then place the sample between two clamps. The sample and the clamp are placed on the same axis, clamp both ends, stretch 15% at a rate of 300 mm / min, and measure the length of the sample paint film that loses adhesion.

[0102] 2. Flexibility test

[0103] The insulated wires of the embodiments and comparative examples were tested for flexibility according to the following methods.

[0104] The flexibility test is carried out using the flexibility test method provided by IEC60851-3 2019 test method 8. The specific steps are as follows:

[0105] Take two 500mm long straight insulated wires, bend them 180±2° around a polished test core, one for flat winding (core diameter = 1 times wire thickness), the other for vertical winding (core diameter = 1 times wire width). In this test, after flat winding and vertical winding, the product with smooth surface and no cracks is recorded as "qualified"; the surface cracks are recorded as "unqualified".

[0106] 3. Insulation breakdown voltage test

[0107] The insulation breakdown voltage is tested using the breakdown voltage test method provided by IEC60851-5 2019 test method 13. The specific steps are as follows:

[0108] Remove the insulation from one end of the insulated wire, bend it flat on a round rod with a diameter of 1 times the wire width, and put it into a metal steel ball container with a thickness of at least 5mm. The end of the sample should extend long enough to avoid flashover. Apply the test voltage between the conductor and the metal steel ball. Boost the voltage at a boost speed of 500V / s and a leakage current of 5mA. Test 5 times and take the average value as the insulation breakdown voltage.

[0109] The test results are shown in the following table:

[0110]

[0111] From the test results, it can be seen that the insulated wire provided by the present invention can significantly improve the adhesion of the insulated wire after adding a base layer made of PEK-C; after adding an appropriate amount of TPI or a mixture of TPI and PEK-C to the outer insulating layer, the adhesion of the insulated wire and its insulation performance at high temperature can also be further improved; the stability and safety of the insulated wire under high temperature conditions are guaranteed, and the service life of the wire is improved.

[0112] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0113] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An insulated wire, characterized in that: It comprises a conductor and a bottom layer and an outer insulating layer sequentially arranged on the outer periphery of the conductor, wherein the bottom layer and the outer insulating layer together serve as the insulating layer of the insulated wire; wherein, The material of the bottom layer is phenolphthalein polyaryletherketone; Along the conductor outward unilateral direction, the thickness of the bottom layer is 5-10 μm; The structure of the phenolphthalein polyaryletherketone has a repeating unit as shown in the following formula 1: Formula 1; The outer insulating layer is obtained by blending and granulating three resins: polyetheretherketone, thermoplastic polyimide and phenolphthalein polyaryletherketone, wherein the mass ratio of the thermoplastic polyimide is 10-90%.

2. The insulated wire according to claim 1, wherein: Along the single-side direction outward from the conductor, the total thickness of the bottom layer and the outer insulating layer is 50-300 μm.

3. A method for preparing an insulated wire according to any one of claims 1-2, characterized in that: The following steps are involved: (1) Preparation of blend: The resin required for the outer insulating layer is blended through a twin-screw extruder at 400-420°C to form a uniform mixing system, and after cooling, it is granulated through a pelletizer to form a particle polymer material required for the outer insulating layer; (2) Insulated wire processing: The resin material of the bottom layer is heated to a molten state, and coated on the surface of the preheated conductor to obtain a core wire; at the same time, the particle polymer material prepared in step (1) is heated to a molten state, coated on the core wire, and cooled to obtain an insulated wire.

4. A coil, characterized in that: The insulated wire is composed of any one of claims 1 to 2.

5. An electronic / electrical device, characterized in that: The invention comprises the coil as claimed in claim 4.

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