JP6027349B2 - Insulated wire and coil using the same - Google Patents

Description

  The present invention relates to an insulated wire and a coil using the same. More specifically, the present invention relates to an insulated wire having a high partial discharge starting voltage, excellent weldability, and excellent flexibility after long-term thermal deterioration, and a coil using the same.

  In recent years, industrial motors are being driven by inverter control because they are desired to be small, light and have high output. For this high voltage drive, combined with inverter surge superposition, the risk of partial discharge occurring in the insulated wire of the motor is increased, and countermeasures for inverter surge insulation are urgently needed.

  Insulated wires having a low partial discharge acceptance voltage (PDIV) so far tend to generate partial discharge, which gradually erodes the film and eventually leads to dielectric breakdown. Therefore, it has not been adequately suited for coils of industrial motors. As a technique to improve the resistance against partial discharge, the dielectric constant of the insulating film (insulating layer) made of polyimide resin formed from polyimide insulating paint (polyimide resin precursor insulating paint) is lowered to make it difficult to generate partial discharge. However, methods for improving resistance have been proposed (see, for example, Patent Documents 1 and 2).

JP 2010-0667408 A JP 2010-153099 A

  In the conventional insulated wire, since the ratio of polar groups is large and the dielectric constant is high, a sufficient partial discharge start voltage cannot be obtained. In the method described in Patent Document 1, although the partial discharge start voltage is improved as compared with the prior art, there is a risk of adverse effects on mechanical properties such as flexibility. In recent years, insulated wires are also expected to be used in high-temperature environments when used, for example, as coils for motor production, and have long-term heat deterioration (film flexibility) and weldability. Is important. However, until now, there has been no insulated wire that satisfies the above-mentioned partial discharge resistance, heat deterioration resistance, and weldability, and development has been an urgent task.

  In order to solve the above-mentioned problems, the present invention aims to provide an insulated wire having a high partial discharge start voltage, excellent weldability and excellent flexibility after long-term thermal deterioration, and a coil using the same. And

  In order to achieve the above object, the present inventors have high PDIV, excellent high temperature weldability and excellent long-term heat deterioration by using an insulating layer made of a polyimide resin into which a specific structure is introduced. Insulated wires suitable for applications such as motor coils have been realized.

  That is, a polyimide resin composed of pyromellitic dianhydride (PMDA) and 4,4′-diaminodiphenyl ether (ODA) is added to 2,2-bis [4 which is a long-chain diamine as a constituent component of the diamine portion. By introducing-(4-aminophenoxy) phenyl] propane (BAPP) and using the resulting polyimide resin for the insulating layer of the insulated wire, the dielectric constant of the insulated wire is reduced, and an insulated wire having a high PDIV is obtained. Achieved.

  Further, the ratio (molar ratio) between ODA and BAPP, which are constituent components of each diamine moiety, which differentiates between the two types of repeating units (A) and (B), is (ODA) / (BAPP). = 50/50 or more and 90/10 or less is preferable, and by configuring in this way, high PDIV, high temperature weldability and long-term heat deterioration resistance are satisfied as compared with conventional polyimide resins. An insulated wire can be realized. Therefore, specifically, in order to achieve the above object, according to the present invention, the following insulated wire and a coil using the same are provided.

[1] A molar ratio of a conductor and a repeating unit represented by the following formula (A) and a repeating unit represented by the following formula (B) provided on the outer periphery of the conductor (repeating unit (A)) N-methyl-2-pyrrolidone (NMP) in the range of 80/20 or more and 90/10 or less (except for the case where the repeating unit (B) is 12 mol% or less). the is dissolved in a solvent of poly Lee bromide resin precursor insulating paint contained consisting applied onto the conductor, together with the obtained by baking, the storage elastic modulus at 300 ° C., a polyimide resin is more than 1000MPa And an insulating wire that is used for welding so that heat higher than the melting point of the polyimide resin is applied to the insulating layer.

[2] The polyimide resin is composed of pyromellitic dianhydride (PMDA), which is a component of the tetracarboxylic dianhydride part of the repeating unit (A) and the repeating unit (B), and a component of a diamine part. A certain 4,4′-diaminodiphenyl ether (ODA) and 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) in a solvent composed of N-methyl-2-pyrrolidone (NMP) insulated wire according poly Lee bromide resin precursor insulating varnish that is contained is dissolved, the is obtained by coating of [1].

[3] A coil using the insulated wire according to [1] or [2].

  ADVANTAGE OF THE INVENTION According to this invention, the insulated wire which has a high partial discharge start voltage, the outstanding weldability, and the flexibility after the long-term thermal deterioration, and a coil using the same can be provided.

[Summary of embodiment]
The insulated wire of the present embodiment is an insulated wire comprising a conductor and an insulating layer made of polyimide resin provided on the outer periphery of the conductor, wherein the insulating layer is a repeating unit represented by the above formula (A) And the repeating unit represented by the above formula (B) in a molar ratio (repeating unit (A) / repeating unit (B)) in the range of 50/50 or more and 90/10 or less, and 300 ° C. The storage elastic modulus is made of a polyimide resin having a viscosity of 1000 MPa or more.

  Hereinafter, a preferred embodiment of the insulated wire of the present invention will be described.

  As described above, the insulated wire of the present embodiment includes a conductor, a repeating unit represented by the above formula (A), and a repeating unit represented by the above formula (B) provided on the outer periphery of the conductor. And a molar ratio (repeating unit (A) / repeating unit (B)) in the range of 50/50 or more and 90/10 or less, and a polyimide resin having a storage elastic modulus at 300 ° C. of 1000 MPa or more. And an insulating layer.

  When the repeating unit (B) constituting the polyimide resin exceeds 50 in terms of molar ratio, the film becomes brittle when formed into a film when exposed for a long time in a high temperature environment. In addition, the elastic modulus at high temperatures is lowered, and there is a risk of deformation or swelling of the film when processed.

  When the repeating unit (B) is less than 10 in terms of molar ratio, the dielectric constant increases and the effect of increasing PDIV cannot be expected. Accordingly, the repeating unit (B) needs to be 10 to 50 in molar ratio.

  The elastic modulus at 300 ° C. of the polyimide resin needs to be 1000 MPa or more in consideration of workability. This is because the insulating layer formed on the outer periphery of the conductor is made of a polyimide resin containing a repeating unit (A) and a repeating unit (B) and having an elastic modulus at 300 ° C. of 1000 MPa or more, so that insulation is achieved for a long time. This is because even if heat is applied to the layer, the insulating layer is not easily deteriorated, and even if heat higher than the melting point of the polyimide resin is instantaneously applied to the insulating layer, the insulating layer is not easily deteriorated. By setting it as the structure provided with such an insulating layer, it can be set as the insulated wire excellent in the weldability in high temperature and long-term heat-resistant deterioration. In particular, considering long-term heat deterioration resistance, the repeating unit (B) is preferably 10 to 30 in terms of molar ratio.

In addition, as described later, the polyimide resin, for example, pyromellitic dianhydride (PMDA) that is a constituent component of the tetracarboxylic dianhydride part of the repeating unit (A) and the repeating unit (B), Containing constituents of the diamine part, 4,4′-diaminodiphenyl ether (ODA) and 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) dissolved in a predetermined solvent poly Lee bromide resin precursor insulating paint, it is obtained by coating of.

  The polyimide resin used in the present embodiment may contain a repeating unit other than the repeating unit (A) and the repeating unit (B) as long as the above-described properties are not impaired. Examples of compounds that can be used in this embodiment are shown below.

"Tetracarboxylic dianhydride component"
Examples of the tetracarboxylic dianhydride component include 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride (BTDA) and 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride. Product (DSDA), 4,4′-oxydiphthalic dianhydride (ODPA), 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA), 4,4 ′-(2,2- And hexafluoroisopropylidene) diphthalic dianhydride (6FDA).

"Diamine component"
Examples of the diamine component include 4,4′-diaminodiphenyl ether (ODA), 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP), and bis [4- (4-aminophenoxy) phenyl. Sulfone (BAPS), bis [4- (4-aminophenoxy) phenyl] ether (BAPE), 4,4′-bis (4-aminophenoxy) biphenyl (BAPB), 1,4-bis (4-aminophenoxy) ) Benzene, 9,9-bis (4-aminophenyl) fluorene (FDA), 1,4-diaminobenzene, 2,4-diaminotoluene, 4,4′-diaminodiphenylmethane, 2,2′-dimethyl-4, 4'-diaminobiphenyl, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 4,4'-diaminoben Phenone, 4,4'-bis (4-aminophenyl) sulfide, 4,4'-diaminodiphenyl sulfone, or can be given their isomers.

  As a method for obtaining the polyimide resin used in the present embodiment, for example, tetracarboxylic dianhydride and the above-described two types of repeating units (repeating unit (A) and repeating unit (B)) are used. There is a method of copolymerizing a diamine containing ODA and BAPP. Alternatively, the polyimide resin having the repeating unit (A) is dissolved in a predetermined solvent and the polyimide resin having the repeating unit (B) is dissolved in a predetermined solvent. However, it is not limited to this.

  In the polyimide resin used in this embodiment, the compounding ratio (molar ratio) of tetracarboxylic dianhydride and diamine containing ODA and BAPP may be shifted from 100: 100. Either tetracarboxylic dianhydride or diamine may be added in excess (for example, 103: 100), and molecular weight control may be performed to improve work. In short, there is no particular limitation as long as the above characteristics are not impaired.

  Solvents include N-methyl-2-pyrrolidone (NMP), γ-butyrolactone, N, N-dimethylacetamide (DMAc), N, N-dimethylformamide (DMF), dimethylimidazolidinone (DMI), cyclohexanone, methyl It may be synthesized in combination with a solvent that does not inhibit the synthesis reaction of polyimide resin such as cyclohexanone, or may be diluted. In addition, aromatic alkylbenzenes and the like may be used in combination for dilution purposes. However, it is necessary to consider when there is a possibility of lowering the solubility of the polyimide resin.

  As an insulated wire of the present embodiment, for example, a polyimide resin layer, for example, a polyimide resin precursor insulating paint is applied to the outer periphery of a conductor having a round or square cross section, or other coating, and an insulating layer ( Examples of the film) include those formed by coating and baking.

  In addition, for example, a lubricant imparting layer for imparting lubricity, a scratch resistance imparting layer for imparting scratch resistance, a flexibility imparting layer, and an insulating layer (skin) on the outer periphery of the insulating layer (skin). An adhesion providing layer or the like may be formed between the circumference and the outer circumference of the conductor by coating and baking.

  Moreover, a conductor consists of a copper conductor and an oxygen-free copper, a low oxygen copper, etc. are mainly used. Note that the conductor is not limited to this, and for example, a conductor obtained by performing metal plating such as nickel on the outer periphery of copper can also be used.

  There is no restriction | limiting in particular as a coil using the insulated wire of this invention, It can manufacture by a general purpose method using the insulated wire of this invention.

Below, the insulated wire of this invention is demonstrated more concretely using an Example. However, Examples 1 , 3, and 4 are reference examples. Note that the present invention is not limited in any way by the following examples.

Example 1
After dissolving 360.9 g of 4,4′-diaminodiphenyl ether (ODA), 82.2 g of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) and 3120 g of NMP, pyromellitic acid 2 436.9 g of anhydride (PMDA) was dissolved and stirred in nitrogen at room temperature for 12 hours to obtain a polyamic acid paint (polyimide resin precursor insulating paint). The obtained polyimide resin precursor insulating coating was applied on a conductor having a diameter of 0.8 mm and baked repeatedly to obtain an insulated wire having an insulating layer made of a polyimide resin having a film thickness of 40 μm. In this case, the molar ratio of the repeating unit (A) to the repeating unit (B) (repeating unit (A) / repeating unit (B)) = 90/10.

(Example 2)
After dissolving 4,4′-diaminodiphenyl ether (ODA) in 306.2 g, 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) in 156.8 g, and NMP3120 g, pyromellitic acid 2 417.0 g of anhydride (PMDA) was dissolved and stirred in nitrogen at room temperature for 12 hours to obtain a polyamic acid paint (polyimide resin precursor insulating paint). Moreover, the obtained polyimide resin precursor insulating coating was applied onto a conductor having a diameter of 0.8 mm and baked repeatedly to obtain an insulated wire having an insulating layer made of a polyimide resin having a film thickness of 40 μm. In this case, the molar ratio of the repeating unit (A) to the repeating unit (B) (repeating unit (A) / repeating unit (B)) = 80/20.

(Example 3)
After dissolving 256.2 g of 4,4′-diaminodiphenyl ether (ODA), 225.0 g of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) and 3120 g of NMP, pyromellitic acid 2 398.8 g of anhydride (PMDA) was dissolved and stirred in nitrogen at room temperature for 12 hours to obtain a polyamic acid paint (polyimide resin precursor insulating paint). Moreover, the obtained polyimide resin precursor insulating coating was applied onto a conductor having a diameter of 0.8 mm and baked repeatedly to obtain an insulated wire having an insulating layer made of a polyimide resin having a film thickness of 40 μm. In this case, the molar ratio of the repeating unit (A) to the repeating unit (B) (repeating unit (A) / repeating unit (B)) = 70/30.

Example 4
After dissolving 168.3 g of 4,4′-diaminodiphenyl ether (ODA), 344.9 g of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) and 3120 g of NMP, pyromellitic acid 2 366.8 g of anhydride (PMDA) was dissolved and stirred in nitrogen at room temperature for 12 hours to obtain a polyamic acid paint (polyimide resin precursor insulating paint). Moreover, the obtained polyimide resin precursor insulating coating was applied onto a conductor having a diameter of 0.8 mm and baked repeatedly to obtain an insulated wire having an insulating layer made of a polyimide resin having a film thickness of 40 μm. In this case, the molar ratio of the repeating unit (A) to the repeating unit (B) (repeating unit (A) / repeating unit (B)) = 50/50.

(Comparative Example 1)
After dissolving 390.3 g of 4,4′-diaminodiphenyl ether (ODA), 42.1 g of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) and 3120 g of NMP, pyromellitic acid 2 447.6 g of anhydride (PMDA) was dissolved and stirred in nitrogen at room temperature for 12 hours to obtain a polyamic acid paint (polyimide resin precursor insulating paint). Moreover, the obtained polyimide resin precursor insulating coating was applied onto a conductor having a diameter of 0.8 mm and baked repeatedly to obtain an insulated wire having an insulating layer made of a polyimide resin having a film thickness of 40 μm. In this case, the molar ratio of the repeating unit (A) to the repeating unit (B) (repeating unit (A) / repeating unit (B)) = 95/5.

(Comparative Example 2)
After dissolving 129.5 g of 4,4′-diaminodiphenyl ether (ODA), 397.9 g of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) and 3120 g of NMP, pyromellitic acid 2 352.6 g of anhydride (PMDA) was dissolved and stirred in nitrogen at room temperature for 12 hours to obtain a polyamic acid paint (polyimide resin precursor insulating paint). Moreover, the obtained polyimide resin precursor insulating coating was applied onto a conductor having a diameter of 0.8 mm and baked repeatedly to obtain an insulated wire having an insulating layer made of a polyimide resin having a film thickness of 40 μm. In this case, the molar ratio of the repeating unit (A) to the repeating unit (B) (repeating unit (A) / repeating unit (B)) = 40/60.

(Characteristic evaluation of insulated wires)
The characteristics (long-term thermal deterioration test, weldability and partial discharge start voltage (PDIV)) of the insulated wires obtained in Examples 1 to 4 and Comparative Examples 1 to 2 were evaluated as follows.

"Partial discharge start voltage (PDIV (Vp))"
A twisted pair insulated wire sample was prepared by the method described in JIS, and the terminal treatment part was formed by scraping the insulating film from the end to a position of 10 mm. The measurement is performed in a withstand voltage mode, an electrode is connected to the terminal processing section, and a 100 pC discharge is applied to the insulated wire of the twisted pair for 50 seconds per second while increasing the voltage of 50 Hz at 10 to 30 V / s in an atmosphere of 23 ° C. × 50% RH. The voltage was raised to the voltage generated twice. This was repeated three times, and the average value of each value was taken as the partial discharge start voltage. With a film thickness of 40 μm, 920 Vp or more was rated as ◯, and less than 920 Vp was rated as x.

"Long-term thermal degradation test (flexibility)"
The obtained insulated wire was put into a constant temperature bath at 220 ° C., and a 500 hr thermal deterioration test was conducted. The film was subjected to a flexibility test after the thermal degradation test, and a crack that did not occur at 5 times diameter (5d or more) passed (○), and a crack occurred at 5 times diameter (if less than 5d). Was marked with x.

"Weldability"
When the obtained insulated wire was Tig welded, the one with good appearance (when there was no abnormality in the appearance such as film swelling) was marked with ○, and the case where the appearance deteriorated due to blistering was marked with ×.

  As for the “storage modulus”, a sheet-like insulating coating for evaluation of 5 mm × 20 mm × 25 μm (thickness) was prepared using each insulating paint. Next, using a dynamic viscoelasticity measuring apparatus (DVA-200 manufactured by IT Measurement Control Co., Ltd.), the temperature is raised from room temperature to 400 ° C. at 10 ° C./min, and the insulating coating for evaluation during 1 Hz vibration is stored. The elastic modulus was measured.

  Finally, the molar ratio and storage elastic modulus of the repeating units (A) and the repeating units (B) of the polyimide resins used in Examples 1 to 4 and Comparative Examples 1 to 2 and the results of property evaluation are shown in Table 1. It summarizes and shows.

(1) Storage modulus: 1000 MPa or more at 300 ° C., less than 1000 MPa x
(2) Long-term thermal deterioration: In a flexibility test after heating at 220 ° C. for 500 hr, 5d or more is indicated as ◯, and 5d or less
(3) Weldability: ○ indicates that there is no blistering in the film near the weld after the weldability test.
(4) PDIV: In an environment of 23 ° C. × 50% RH, 920 Vp or more is ○, and less than 920 Vp is ×

  As shown in Table 1, it can be seen that the insulated wires according to Examples 1 to 4 have a high partial discharge start voltage (PDIV) and are excellent in weldability at high temperatures and long-term heat deterioration.

  On the other hand, the insulated wire according to Comparative Example 1 was excellent in weldability at high temperatures and long-term heat deterioration, but had a low partial discharge start voltage (PDIV). Moreover, although the insulated wire which concerns on the comparative example 2 had high partial discharge start voltage (PDIV), it was a result inferior in the weldability in high temperature and long-term heat-resistant deterioration.

  While the embodiments and examples of the present invention have been described above, the above-described embodiments and examples do not limit the invention according to the claims. In addition, it should be noted that not all the combinations of features described in the embodiments and examples are essential to the means for solving the problems of the invention.

Claims (3)

Conductors,
The repeating unit represented by the following formula (A) and the repeating unit represented by the following formula (B) provided on the outer periphery of the conductor are in a molar ratio (repeating unit (A) / repeating unit (B). ) And dissolved in a solvent composed of N-methyl-2-pyrrolidone (NMP) in the range of 80/20 or more and 90/10 or less (except when the repeating unit (B) is 12 mol% or less). is poly Lee bromide resin precursor insulating varnish that is contained is applied onto the conductor, together with the obtained by baking, storage elastic modulus at 300 ° C. is an insulating layer made of a polyimide resin is more than 1000 MPa, the Prepared,
An insulated wire used for welding so that heat higher than the melting point of the polyimide resin is applied to the insulating layer.
The polyimide resin is composed of pyromellitic dianhydride (PMDA), which is a constituent of the tetracarboxylic dianhydride part of the repeating unit (A) and the repeating unit (B), and a constituent of the diamine part. 4′-diaminodiphenyl ether (ODA) and 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) are dissolved in a solvent composed of N-methyl-2-pyrrolidone (NMP). the insulated wire according to claim 1 poly Lee bromide resin precursor insulating varnish that is contained, those obtained by coating of. The coil using the insulated wire of Claim 1 or 2.