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

Abstract

The present invention discloses an insulated wire and a preparation method thereof, a coil and an electronic / electrical device, which relate to the technical field of insulated wires, and include a conductor, an insulating layer and a self-adhesive layer sequentially arranged around the conductor, wherein the self-adhesive layer is a modified polyamide-imide resin, and the modified polyamide-imide resin contains a long-chain aliphatic structural monomer. The insulated wire provided by the present invention has excellent adhesion at high temperatures and can be used in high temperature scenes above 200°C. The overall cost of raw materials for the client's impregnation varnish, the cost of the impregnation varnish coating process and the labor cost can be reduced.

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] The traditional motor coil winding process usually requires varnish dipping. The main functions of the dipping varnish are: first, the motor dipping varnish can penetrate between the motor winding and the core to form a layer of insulating protective film to prevent current leakage and insulation damage. Second, the motor dipping varnish can enhance the mechanical strength of the motor winding and prevent the winding from deformation or damage during operation. Due to the limitation of heat resistance level, the motor dipping varnishes currently on the market are all thermosetting paint liquids. The process of motor dipping requires cleaning the motor first, then dipping, and then curing the dipping varnish. The whole processing process is very complicated and the cost is very high. Moreover, since the dipping varnish is a thermosetting resin, once the dipping fails, the entire motor needs to be scrapped.

[0003] Therefore, the industry is currently trying to coat the outer periphery of the insulated wire with a self-adhesive layer to make a self-adhesive insulated wire to replace the dipping varnish. Because the self-adhesive insulated wire can be bonded during the winding process, or after the winding is completed, the entire motor is heated to soften the self-adhesive layer and bond to each other, and then the coil can be solidified after cooling. However, the self-adhesive paint currently on the market has a low heat resistance level and can usually only withstand high temperatures of 120-180°C. When the temperature exceeds this range, the self-adhesive insulation layer will lose its adhesion, causing the coil to loosen and fall off, affecting the normal use and safety of the wire. Secondly, the self-adhesive paints commonly used on the market are mostly materials such as polyamide or epoxy resin, and the insulation effect of such materials is poor. Therefore, the existing self-adhesive insulated wires still have a lot of room for improvement in terms of heat resistance and insulation effect. Summary of the invention

[0004] In view of this, the main purpose of the present invention is to provide an insulated wire. The insulated wire provided by the present invention has excellent adhesion at high temperatures, can be used in high temperature scenes above 200°C, and has good insulation performance.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] An insulated wire comprises a conductor, an insulating layer and a self-adhesive layer sequentially arranged around the conductor, wherein the self-adhesive layer is a modified polyamide-imide resin, and the modified polyamide-imide resin contains a long-chain aliphatic structural monomer, that is, the modified polyamide-imide resin is a long-aliphatic chain polyamide-imide (abbreviated as long-aliphatic chain PAI).

[0007] Furthermore, the structure of the modified polyamide-imide resin is shown in Formula 4 below:

[0008]

[0009] Formula 4;

[0010] Wherein, R1 is an aliphatic group with no less than 4 carbon atoms; R2 is selected from aliphatic, alicyclic, and aromatic hydrocarbon groups; and n is 3-20, preferably 5-10.

[0011] Further, the R1 is a long-chain aliphatic hydrocarbon group having 6 to 36 carbon atoms, and more preferably a long-chain aliphatic hydrocarbon group having 10 to 24 carbon atoms. Preferably, the aliphatic hydrocarbon group is a saturated aliphatic alkylene group.

[0012] Furthermore, the preparation method of the long aliphatic chain PAI, i.e., the above formula 4, comprises the following steps:

[0013] 1) Tricarboxylic acid + aliphatic diamine reacts to form an imine prepolymer containing an aliphatic chain:

[0014] The diamine shown in Formula 1 is reacted with tricarboxylic acid to generate an imine with the following structure:

[0015]

[0016] Formula 1;

[0017]

[0018] Formula 2;

[0019] Wherein, R1 is a long-chain aliphatic group of not less than 4 carbons, preferably a long-chain aliphatic hydrocarbon group of 6-36 carbons, and more preferably a long-chain aliphatic hydrocarbon group of 10-24 carbons; preferably, the aliphatic hydrocarbon group is a saturated aliphatic alkylene group.

[0020] 2) reacting the structure shown in formula 2 obtained in step 1) with diisocyanate to obtain PAI shown in formula 4;

[0021] Wherein, the structural formula 3 of the diisocyanate is as follows:

[0022]

[0023] Formula 3;

[0024] R2 is selected from aliphatic, alicyclic, and aromatic hydrocarbon groups, and the diisocyanate can be optionally toluene diisocyanate (TDI for short), diphenylmethane diisocyanate (MDI for short), isophorone diisocyanate (IPDI for short), methylene diisocyanate (HDI for short) or a combination thereof.

[0025] Further, in step 1), specifically, under reflux conditions, the compound represented by formula 1 and tricarboxylic acid are mixed in a solvent, and refluxed and heated for reaction, the heating temperature is 180-200° C., the reaction time is 1-3 hours, preferably 2 hours; after the reaction is completed, the solvent is removed;

[0026] Preferably, the solvent is removed by distillation under vacuum conditions of about 0.1 to 0.5 kPa.

[0027] The molar ratio of the structure shown in Formula 1 to tricarboxylic acid is 1:1-3, preferably 1:2.

[0028] Furthermore, the reaction temperature in step 2) is 180-200°C; the reaction time is also 1-3h, preferably 2h; the diisocyanate is 2.2-2.5 times the structure shown in formula 1, preferably 2.4 times.

[0029] Furthermore, the insulating layer is at least one of polyamide-imide (PAI for short) resin and polyimide (PI for short) resin.

[0030] Furthermore, along a single side direction outward from the conductor, the thickness of the self-adhesive layer is greater than or equal to 5 μm on a single side.

[0031] Furthermore, the self-adhesive layer has a tackiness temperature of 190° C., an optimum bonding temperature of the self-adhesive layer of 230-270° C., and a temperature at which the self-adhesive layer loses its adhesive force of ≥300° C. Furthermore, the dielectric constant of the self-adhesive layer is less than 3.0.

[0032] Furthermore, the dielectric constant of the self-adhesive layer is preferably 2.6-2.8.

[0033] A second object of the present invention is to provide a coil composed of the above-mentioned insulated wire.

[0034] It should be noted that the coil provided by the present invention is mainly used in motors or generators with high temperature and high power in the use scene. During the coil winding process, the insulated wire can be heated so that the self-adhesive layer can produce viscosity during the winding process, and the insulated wires are bonded to each other as a whole. Finally, the coil is installed in the stator and cooled to make a finished motor. After the insulated wire is installed in the stator, the electronics and the coil can be heated as a whole so that the self-adhesive layer gradually produces viscosity, thereby bonding the insulated wires to each other as a whole to avoid gaps and looseness; the insulated wire provided by the present invention can replace the processing technology of dipping the motor in the prior art, and can reduce the client's dipping paint raw material cost, dipping paint coating process cost and labor cost as a whole. And the insulated wire provided by the present invention will gradually begin to debond when the temperature reaches above 280°C; the debonding temperature far exceeds the heat resistance level of the insulating layer and the peak temperature of the motor, which can effectively ensure its bonding effect, as well as the uniformity and stability of its insulation effect.

[0035] The present invention also aims to provide an electrical or electronic device prepared from the coil.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] The insulated wire provided by the present invention solves the problem that the traditional self-adhesive insulated wire has a low heat resistance level and the coil is easily loosened and falls off due to high temperature. The insulated wire provided by the present invention starts to debond at 280°C, and the temperature to completely lose the adhesive force needs to be ≥300°C. DETAILED DESCRIPTION

[0038] 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.

[0039] 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.

[0040] Example 1 (Conductor size 2.00 x 3.00 mm)

[0041] 1) Preparation of polyamide-imide resin containing aliphatic chains

[0042] In a flask equipped with a reflux condenser, add 0.1 mol of hexamethylenediamine, further add 0.2 mol of trimellitic anhydride (TMA for short), add 100 ml of ethylbenzene, and reflux at 180°C for 2 hours. Remove the reflux, increase the temperature to about 200°C to distill off the solvent ethylbenzene. Then, cool to room temperature, add 0.24 mol of MDI and 100 ml of N-methylpyrrolidone (solvent), and reflux at 190°C for 2 hours. After the reaction is completed, a solution of polyamide-imide resin containing aliphatic chains, i.e., long aliphatic chain PAI, is obtained.

[0043] 2) The long aliphatic chain PAI paint obtained in step 1) is applied to an insulated wire coated with a PI layer (thickness of 100 μm), and after baking and curing, a modified PAI coated wire with a self-adhesive layer thickness of about 15 μm is obtained, that is, an insulated wire is obtained.

[0044] Among them, polyimide (PI for short) in the insulating layer is a common commercial product.

[0045] Example 2

[0046] 1) Preparation of polyamide-imide resin containing aliphatic chains

[0047] In the same manner as in Example 1, TMA (0.2 mol) and 1,12-dodecyl diamine (0.1 mol) were dissolved in ethylbenzene solvent and refluxed at 200°C, and the solvent was removed after the reaction. Subsequently, 2.4 equivalents of MDI (0.24 mol) and 100 ml of N-methylpyrrolidone were added based on the amount of 1,12-dodecyl diamine, and refluxed at 190°C for 2 hours to obtain an aliphatic chain PAI containing 12 carbon atoms.

[0048] 2) The aliphatic chain PAI paint containing 12 carbon atoms obtained in step 1) is applied to an insulated wire coated with a PAI layer (thickness of 100 μm), and after baking and curing, a modified PAI coated wire with a self-adhesive layer thickness of about 15 μm is obtained, that is, an insulated wire is obtained.

[0049] Among them, polyamide-imide (PAI for short) in the insulating layer is a common commercial product.

[0050] Example 3

[0051] 1) Preparation of polyamide-imide resin containing aliphatic chains

[0052] Using the same method and experimental conditions as in Example 1, TMA (0.2 mol) and 1,18-octadecanediamine (0.1 mol) were dissolved in ethylbenzene solvent and refluxed at 200°C, and the solvent was removed after the reaction. Subsequently, based on the amount of 1,12-dodecanediamine, 2.4 equivalents of MDI (0.24 mol) and 100 ml of N-methylpyrrolidone were added, and refluxed at 200°C for 2 hours to obtain an aliphatic chain PAI containing 18 carbon atoms.

[0053] 2) Similarly, according to the corresponding steps in Example 1, an insulated wire is obtained.

[0054] Example 4

[0055] 1) Preparation of polyamide-imide resin containing aliphatic chains

[0056] Using the same method and experimental conditions as in Example 2, TMA and 1,12-dodecanediamine in an equivalent ratio of 2:1 were dissolved in ethylbenzene solvent and refluxed at 200°C, and the solvent was removed after the reaction. Subsequently, based on the amount of 1,12-dodecanediamine dissolved, 2.4 equivalents of HDI and an appropriate amount of N-methylpyrrolidone were added, and refluxed at 200°C for 2 hours to obtain an aliphatic chain PAI containing 12 carbon atoms.

[0057] 2) Similarly, according to the corresponding steps in Example 1, an insulated wire is obtained.

[0058] Example 5

[0059] 1) Preparation of polyamide-imide resin containing aliphatic chains

[0060] Using the same method and experimental conditions as in Example 2, TMA and 1,12-dodecanediamine in an equivalent ratio of 2:1 were dissolved in ethylbenzene solvent and refluxed at 200°C, and the solvent was removed after the reaction. Subsequently, based on the amount of 1,12-dodecanediamine, 2.2 equivalents of MDI and an appropriate amount of N-methylpyrrolidone were added, and the reaction was refluxed at 200°C for 2 hours to obtain an aliphatic chain PAI containing 12 carbon atoms.

[0061] 2) Similarly, according to the corresponding steps in Example 1, an insulated wire is obtained.

[0062] Example 6

[0063] 1) Preparation of polyamide-imide resin containing aliphatic chains

[0064] Using the same method and experimental conditions as in Example 2, TMA (0.2 mol) with an equivalent ratio of 2:1 and a mixed amine of 1,12-dodecanediamine (0.05 mol) and p-phenylenediamine (0.05 mol), the two amines were fed in an equivalent ratio of 1:1 and dissolved in an ethylbenzene solvent, and refluxed at 200°C. After the reaction, the solvent was removed. Subsequently, based on the amount of the mixed amine, 2.4 equivalents of MDI (0.24 mol) and 100 ml of N-methylpyrrolidone were added, and the mixture was refluxed at 200°C for 2 hours to obtain an aliphatic chain PAI containing 12 carbon atoms.

[0065] 2) Similarly, according to the corresponding steps in Example 1, an insulated wire is obtained.

[0066] Example 7

[0067] 1) Preparation of polyamide-imide resin containing aliphatic chains

[0068] Using the same method and experimental conditions as in Example 6, TMA (0.2 mol) with an equivalent ratio of 2:1 and a mixed amine of 1,12-dodecanediamine (0.04 mol) and p-phenylenediamine (0.06 mol), with the feed equivalent ratio of the two amines being 2:3, was dissolved in an ethylbenzene solvent, and refluxed at 200°C, and the solvent was removed after the reaction. Subsequently, based on the amount of the mixed amine, 2.4 equivalents of MDI (0.24 mol) and 100 ml of N-methylpyrrolidone were added, and the mixture was refluxed at 200°C for 2 hours to obtain an aliphatic chain PAI containing 12 carbon atoms.

[0069] 2) Similarly, according to the corresponding steps in Example 1, an insulated wire is obtained.

[0070] Comparative Example 1

[0071] 1) Using the same method as in Example 1, TMA (0.2 mol) and p-phenylenediamine (0.1 mol) with an equivalent ratio of 2:1 were refluxed at 200°C, and the solvent was removed after the reaction. Subsequently, based on the amount of TMA, 2.4 equivalents of MDI (0.24 mol) and 100 ml of N-methylpyrrolidone were added, and the mixture was refluxed at 190°C for 2 hours to obtain a self-adhesive coating liquid.

[0072] 2) Similarly, according to the corresponding steps in Example 1, an insulated wire is obtained.

[0073] Comparative Example 2

[0074] 1) Using the same method and experimental conditions as in Example 2, TMA and 1,12-dodecanediamine in an equivalent ratio of 2:1 were refluxed at 200°C, and the solvent was removed after the reaction. Subsequently, based on the amount of 1,12-dodecanediamine, 2.05 equivalents of MDI and an appropriate amount of N-methylpyrrolidone were added, and the reaction was refluxed at 200°C for 2 hours to obtain an aliphatic chain PAI containing 12 carbon atoms.

[0075] 2) Paint according to the corresponding steps in Example 1;

[0076] Since the viscosity of the self-adhesive layer paint liquid prepared in this embodiment exceeds 8000cp, it is difficult to coat and level, and the obtained self-adhesive layer is thick and uneven in thickness, which is not suitable for the self-adhesive layer.

[0077] Comparative Example 3

[0078] 1) TMA (0.2 mol) with an equivalent ratio of 2:1 and a mixed amine of 1,12-dodecanediamine (0.01 mol) and p-phenylenediamine (0.09 mol), with the equivalent ratio of the two amines being 1:9, was dissolved in ethylbenzene solvent, refluxed at 200°C, and the solvent was removed after the reaction. Subsequently, based on the amount of TMA, 2.4 equivalents of MDI (0.24 mol) and 100 ml of N-methylpyrrolidone were added, and refluxed at 200°C for 2 hours to obtain an aliphatic chain PAI containing 12 carbon atoms.

[0079] 2) Similarly, according to the corresponding steps in Example 1, an insulated wire is obtained.

[0080] Comparative Example 4

[0081] 1) A thermoplastic polyamide resin paint is applied to an insulated wire coated with a PI layer (100 μm thick), and after baking and curing, a wire having a self-adhesive layer thickness of about 15 μm is obtained.

[0082] Among them, thermoplastic polyamide resin is a general commercial product.

[0083] Comparative Example 5

[0084] The difference from Example 1 is that the thickness of the insulating layer is 115 μm, the insulating layer is a PI layer, and there is no self-adhesive layer outside the insulating layer.

[0085] Performance Test:

[0086] The wires obtained in the examples and comparative examples were subjected to the following tests

[0087] 1. Adhesion test: without any stretching or bending, take a piece of suitable length as a sample and wind it into a coil. Then bake the coil at 170℃~270℃ for 15 minutes. After cooling at room temperature, hang the coil vertically and attach a weight to the lower end of the coil to check the adhesion of the sample (unit: N).

[0088]

[0089] 2. Debonding test:

[0090] Step 1) Making a coil: without any stretching or bending, take a piece of suitable length as a sample and wind it into a coil, then bake the coil at a suitable temperature for 15 minutes and cool it at room temperature. Examples 1 to 7 and Comparative Examples 1-3 are baked at 230°C for 15 minutes, and Comparative Examples 4 and 5 are baked at 200°C for 15 minutes.

[0091] Step 2) Heating and debonding: After the coil has cooled, bake it at 180°C~300°C for 15 minutes to observe the bonding condition.

[0092]

[0093] 3. Insulation Breakdown Voltage (BDV) Test

[0094] Remove the insulation layer from one end of the insulated wire, bend the wide side on a φ25mm round bar, and put it into a metal steel ball container with a thickness of at least 5mm. The end of the sample should be extended 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.

[0095]

[0096] In summary, the insulated wire provided by the present invention has a self-adhesive layer with a higher heat resistance level and an excellent bonding effect in a high temperature environment. The problem of the coil loosening and falling off will not occur, and it can be applied to high temperature scenes above 200°C. The insulated wire has good breakdown resistance, which can effectively improve the stability and safety of the insulated wire and increase the service life of the wire.

[0097] 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.

[0098] 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. A self-adhesive insulated wire, characterized in that: It comprises a conductor, an insulating layer and a self-adhesive layer sequentially arranged around the conductor, wherein the self-adhesive layer is a modified polyamide-imide resin, and the modified polyamide-imide resin contains a long-chain aliphatic structural monomer; The structure of the modified polyamide-imide resin is shown in Formula 4 below: Formula 4; Wherein, R1 is a long-chain aliphatic group of not less than 4 carbon atoms; R2 is selected from aliphatic, alicyclic, and aromatic hydrocarbon groups; n is 3-20; The preparation method of the modified polyamide-imide resin comprises: 1) Tricarboxylic acid + aliphatic diamine reacts to form an imine prepolymer containing an aliphatic chain: The diamine shown in Formula 1 is reacted with tricarboxylic acid to generate an imine with the following structure: Formula 1; Formula 2; 2) reacting the structure shown in Formula 2 obtained in step 1) with diisocyanate to obtain a modified polyamide-imide resin shown in Formula 4; Wherein, the structural formula 3 of the diisocyanate is as follows: Formula 3; The diisocyanate is toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, methylene diisocyanate or a combination thereof; In step 2), the diisocyanate is 2.2-2.5 times the structure shown in formula 1; The adhesive temperature of the self-adhesive layer is 190° C., the optimal adhesive temperature of the self-adhesive layer is 230-270° C., and the temperature at which the self-adhesive layer loses its adhesive force is ≥300° C.

2. The insulated wire according to claim 1, wherein: The R1 is an aliphatic hydrocarbon group having 6-36 carbon atoms, and n is 5-10.

3. The insulated wire according to claim 1, wherein: The insulating layer is at least one of polyamide-imide resin and polyimide resin.

4. The insulated wire according to claim 1, wherein: Along the unilateral direction outward from the conductor, the thickness of the self-adhesive layer is greater than or equal to 5 μm on one side.

5. The insulated wire according to claim 1, wherein: The dielectric constant of the self-adhesive layer is less than 3.

0.

6. The insulated wire according to claim 5, characterized in that The dielectric constant of the self-adhesive layer is 2.6-2.

8.

7. A coil, characterized in that: The insulated wire is composed of any one of claims 1 to 6.

8. An electrical / electronic device, characterized in that: The invention comprises the coil as claimed in claim 7.

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