WO2020171617A1 - Composition for insulation film, and insulated electric wire comprising insulation film formed therefrom - Google Patents

Abstract

The present invention relates to a composition for an insulation film, and an insulated electric wire comprising an insulation film formed therefrom. Specifically, the present invention relates to: a composition for an insulation film, having a low relative permittivity so as to have a high partial discharge inception voltage and, simultaneously, having excellent heat resistance so as to be stable at a high temperature, and having excellent flexibility; and an insulated electric wire comprising an insulation film formed therefrom.

Description

Insulated wire comprising composition for insulating film and insulating film formed therefrom

The present invention relates to an insulating electric wire comprising a composition for an insulating film and an insulating film formed therefrom. Specifically, the present invention relates to an insulating wire comprising a composition for an insulating film having low relative dielectric constant and high partial discharge initiation voltage and excellent heat resistance, stable at high temperature, and excellent flexibility, and an insulating film formed therefrom.

Insulated wires (enamel wires) applied as coils of rotating electric machines such as motors or electric devices such as transformers are made of resins such as polyimide, polyamideimide, and polyesterimide on the surface of a metal conductor with a circular or square cross-sectional shape. It can be produced by covering with an insulating paint dissolved in a solvent to form one or two or more insulating films.

Since electric devices such as rotating electric machines and transformers are driven by inverter control, if the inverter surge voltage generated by the inverter control is high, partial discharge occurs due to the inverter surge voltage in the insulated wire constituting the coil of the electric device and insulates it. The insulating film of the electric wire may be deteriorated or damaged.

Therefore, conventional insulated wires contain inorganic particles such as silica in the insulating film to prevent deterioration or damage of the insulating film due to inverter surge voltage, but these inorganic particles increase the relative dielectric constant of the insulating film, and as a result, the insulating wire The partial discharge inception voltage of may be reduced, and flexibility may be greatly reduced.

On the other hand, in the conventional insulated wire, in order to suppress an increase in the relative dielectric constant due to inorganic particles added to the insulating film, an aromatic diamine component having three or more aromatic rings and an aromatic imide prepolymer containing an acid component have two or less aromatics. A polyimide resin coating obtained by mixing an aromatic diisocyanate component having a ring was applied. However, such a polyimide resin coating has low heat resistance and thus a stable insulating film at high temperature cannot be formed. In recent years, since the characteristics of rotating electric machines such as motors are also considered under high-temperature environments, high-temperature stability of the insulating film is becoming important.

Accordingly, there is an urgent need for a composition for an insulating film having a low relative dielectric constant, a high partial discharge starting voltage, and excellent heat resistance, stable at high temperatures, and excellent flexibility, and an insulating wire including an insulating film formed therefrom.

An object of the present invention is to provide a composition for an insulating film having a low relative dielectric constant, high partial discharge initiation voltage, and excellent flexibility, and an insulating wire including an insulating film formed therefrom.

Another object of the present invention is to provide an insulating wire comprising a composition for an insulating film stable at high temperature and an insulating film formed therefrom.

In order to solve the above problems, the present invention,

As a composition for an insulating film, it includes a polyimide resin formed through polymerization of a dianhydride compound and a diamine compound, the dianhydride compound includes a tetracarboxylic dianhydride or an isomer thereof, and the diamine compound is a first diamine A compound and a second diamine compound, wherein the first diamine compound is 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 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), 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-bis(4- Aminophenyl) sulfide and one or more selected from the group consisting of isomers thereof, and the second diamine compound is selected from the group consisting of 1,4-diaminobenzene, 2,4-diaminotoluene, and isomers thereof. It provides a composition for an insulating film containing one or more.

Here, a molar ratio of the first diamine compound and the second diamine compound is greater than 50:50 and less than or equal to 95:5, providing a composition for an insulating film.

In addition, the tetracarboxylic dianhydride is 1 selected from the group consisting of pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), and isomers thereof. It provides a composition for an insulating film, characterized in that it contains more than one species.

Furthermore, in the tetracarboxylic dianhydride, the pyromellitic dianhydride (PMDA) and 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) are 30:70 or more and 70:30 or less. It provides a composition for an insulating film, characterized in that mixed in a molar ratio of.

In addition, the polyimide resin provides a composition for an insulating film, characterized in that it has a molecular structure of the following formula (1).

[Formula 1]

In Formula 1,

n is 5 to 200.

Here, the polyimide resin provides a composition for an insulating film, characterized in that the number average molecular weight (Mn) is 10,000 to 200,000.

Furthermore, N-methyl-2-pyrrolidone (NMP), γ-butyrolactone, N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethylimidazolidinone (DMI ), cyclohexanone, methylcyclohexanone and aromatic alkyl benzenes, characterized in that it comprises at least one solvent selected from the group consisting of, provides a composition for an insulating film.

Meanwhile, a conductor; And an insulating film formed on the surface of the conductor and formed from the composition for insulating film.

Here, the insulating film is formed on the surface of the conductor and includes a first insulating film comprising at least one resin selected from the group consisting of polyimide resin, polyamideimide resin, and polyesterimide resin; And a second insulating film formed on the first insulating film and formed from the composition for an insulating film of claim 1 or 2.

Here, the second insulating film has a thickness of 85% or more of the total thickness of the insulating film.

In addition, an insulated wire, characterized in that it further comprises at least one layer selected from the group consisting of an adhesion-improving layer formed on the surface of the conductor, a lubricating layer formed on the surface of the insulating film or the surface of the second insulating film, and a highly flexible layer Provides.

Since the composition for an insulating film according to the present invention contains a polyimide resin having a specific molecular structure, the relative dielectric constant is low, the partial discharge initiation voltage is high, and the heat resistance is excellent, so that it is stable at high temperatures and has excellent flexibility.

1 shows an embodiment of an insulated wire according to the present invention.

Figure 2 shows another embodiment of the insulated wire according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art. The same reference numbers throughout the specification denote the same elements.

The composition for an insulating film according to the present invention may include a polyimide resin formed through polymerization of a dianhydride compound and a diamine compound, wherein the dianhydride compound is, for example, tetracarboxylic dianhydride, preferably fatigue. Melitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), and the like, or isomers thereof.

Meanwhile, in the tetracarboxylic dianhydride, the pyromellitic dianhydride (PMDA) and 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) are 30:70 or more and 70:30 or less. It can be mixed in a molar ratio of. The insulated wire according to the present invention can be applied in automobiles, and oil resistance must be secured due to the environment exposed to engine oil, etc., and pyromellitic dianhydride (PMDA) and 3,3',4,4'-biphenyltetra When the carboxylic acid dianhydride (BPDA) is in the above range, sufficient oil resistance can be secured.

In addition, the diamine compound may include a first diamine compound and a second diamine compound, and the first diamine compound is, for example, 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP ), 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), 2,2'-dimethyl-4,4'- Diaminobiphenyl, 4,4'-bis(4-aminophenyl)sulfide, etc. or isomers thereof, and the second diamine compound is, for example, 1,4-diaminobenzene, 2,4- Diaminotoluene and the like or isomers thereof.

The first diamine compound is a compound having polarity and may lower the relative dielectric constant, but there is a problem in that heat resistance may decrease when excessively added. Therefore, it was confirmed that heat resistance can be secured by mixing the second diamine compound to compensate for this.

Here, the molar ratio of the first diamine compound and the second diamine compound may be greater than 50:50 and not greater than 95:5. When the molar ratio of the first diamine compound and the second diamine compound is 50:50 or less, the relative dielectric constant of the composition for an insulating film increases, thereby reducing the partial discharge initiation voltage of the insulated wire having the insulating film formed therefrom. On the other hand, when the molar ratio is more than 95:5, heat resistance of the composition for insulating coating is lowered, and thus usability insulated wires cannot be manufactured under a high temperature environment.

Accordingly, the composition for an insulating film according to the present invention may include a polyimide resin having a molecular structure represented by Formula 1 below.

[Formula 1]

In Formula 1,

n is 5 to 200.

Meanwhile, the polyimide resin may have a number average molecular weight (Mn) of 10,000 to 200,000, and preferably 13,000 to 80,000.

The n and number average molecular weight (Mn) are measures of molecular weight, and if the molecular weight is too small, sufficient viscosity may not be secured, making it difficult to form an insulating film, and if the molecular weight is too large, the viscosity increases and the coating operation is difficult. Sex problems can occur.

The composition for an insulating film according to the present invention has a low ratio of polar groups in the molecular structure of the polyimide resin, so that the relative dielectric constant of the composition can be lowered and the heat resistance can be improved, and since there is no need to contain inorganic particles, it has flexibility. great.

In the composition for an insulating film according to the present invention, the polyimide resin is N-methyl-2-pyrrolidone (NMP), γ-butyrolactone, N,N-dimethylacetamide (DMAc), N,N-dimethylform It may be dissolved in a solvent such as amide (DMF), dimethylimidazolidinone (DMI), cyclohexanone, methylcyclohexanone, and aromatic alkyl benzenes.

1 shows an embodiment of an insulated wire according to the present invention.

As shown in Figure 1, the insulated wire according to the present invention may include a conductor 10 and an insulating film 20 formed on the surface of the conductor 10 and formed from the composition for an insulating film as described above, , The thickness of the insulating film 20 may be, for example, 0.01 to 0.1 mm.

The conductor 10 may be made of copper, preferably oxygen-free copper or hypoxic copper, and the cross-sectional shape thereof is circular as shown in FIG. 1A or a cross-sectional shape as shown in FIG. It may be a curved square.

Figure 2 shows another embodiment of the insulated wire according to the present invention.

As shown in Figure 2, the insulated wire according to the present invention is formed on the surface of the conductor 10, the conductor 10, and is made of a conventional general polyimide resin, polyamideimide resin, polyesterimide resin, etc. An insulating film 21 and a second insulating film 22 formed on the first insulating film 21 and formed from the composition for an insulating film as described above may be included.

Here, the thickness of the second insulating film 22 may be 85% or more of the total thickness of the insulating film 20, for example, 85% or more and less than 100%. When the thickness of the second insulating film 22 is less than 85% of the total thickness of the insulating film 20, the dielectric constant of the insulating film of the insulating wire according to the present invention increases, so that the partial discharge initiation voltage of the insulated wire decreases or heat resistance It is degraded and cannot be used under high temperature environments.

In addition, the insulated wire according to the present invention includes the conductor 10 and the insulating film or the first insulating film between the surface of the conductor 10 or between the first insulating film 21 and the second insulating film 22. In order to improve the adhesion between the film 21 and the second insulating film 22, an adhesion-improving layer may be additionally included, or the surface of the insulating film 20 or the second insulating film 22 may have a lubricating layer, intrinsic It may further include a soft layer and the like.

[Example]

1. Manufacturing example

Solid content concentration by mixing the compounds shown in Table 1 below in the solvent N-methyl-2-pyrrolidone (NMP) for 12 hours at the stated content using a stirrer, reflux condenser, nitrogen inlet tube and a flask equipped with a thermometer. An insulating film having a thickness of 15% by weight was prepared, an insulating film was prepared therefrom, and an insulating film having a thickness of 0.04 mm was formed by coating the surface of a copper conductor with the insulating film. The units of the content listed in Table 1 below are mol%.

	Example 1	Example 2	Example 3	Comparative Example 1	Comparative Example 2	Comparative Example 3	Comparative Example 4	Comparative Example 5
PMDA	50	50	50	50	50	50	50	PAI
BPDA	50	50	50	50	50	50	50
BAPP	95	80	70	98	50	20	0
PDA	5	20	30	2	50	80	100

-PMDA: pyromellitic anhydride (molecular weight: 218)-BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride (molecular weight: 294)

-BAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]propane (molecular weight: 410)

-P-phenylenediamine (molecular weight: 108)

-PAI: Polyamideimide resin (manufacturer: COMEX; product name: GM38K)

2. Property evaluation

1) Filming evaluation

After heat treatment at 80°C for 10 minutes, 150°C for 10 minutes, 200°C for 10 minutes, and 250°C for 10 minutes, each of Examples and Comparative Examples was dried in a vacuum oven at 200°C for 24 hours, and then visually Observation was carried out, and according to the state of the formed film, it was marked as ○ (good), △ (slightly poor), and x (defective).

2) dielectric constant measurement

Examples and Comparative Examples After preparing an insulating film having a width of 100 mm, a length of 100 mm, and a thickness of 50 μm from the composition for each insulating coating, the capacitance between electrodes was measured with an LCR meter, and the measured capacitance value and the film The dielectric constant was calculated from the thickness. The capacitance measurement was performed under conditions of a temperature of 23° C. and a humidity of 50%.

3) Decomposition temperature (heat resistance) measurement

The temperature at which a 10% mass loss occurs was measured as the decomposition temperature for the insulating film formed from the insulating film composition of each of the examples and comparative examples using TGA.

4) Measurement of partial discharge start voltage

Each insulated wire of Examples and Comparative Examples was cut into 500 mm to prepare 10 insulated wire specimens of a twisted pair, and the insulating film was removed from the end of each of the insulated wires to a position of 10 mm to form a terminal treatment part. The voltage was measured at the point where 10 pC discharge occurred 50 times per second on the insulated wire specimen while boosting the voltage of 50 Hz to 10 to 30 V/s under 25°C and 50% humidity, and this was measured by repeating 3 times. The average value of the resulting voltage was described as the partial discharge start voltage.

5) Flexibility evaluation

Flexibility was evaluated according to the standard IEC 60851-3. Specifically, in order to make the insulated wire specimens of each of the Examples and Comparative Examples having a length of 400 mm in an elongated S shape, they were bent at 180° along a polishing mandrel having a diameter given in the corresponding standard in two directions and bent in a U shape. The part should be at least 150 mm. In this case, if no cracks occurred on the surface of the insulated wire specimen, it was marked as OK, and if cracks occurred, it was marked as NG.

	Example 1	Example 2	Example 3	Comparative Example 1	Comparative Example 2	Comparative Example 3	Comparative Example 4	Comparative Example 5
Filming	○	○	○	○	△	×	×	○
permittivity	2.35	2.43	2.43	2.32	2.51	-	-	4.7
Decomposition temperature(℃)	565	579	590	510	595	-	-	420
Partial discharge start voltage (V)	1150	1130	1130	1140	1100	-	-	910
flexibility	OK	OK	OK	OK	NG	-	-	OK

As shown in Table 2, in the case of Examples 1 to 3 corresponding to the composition for an insulating film according to the present invention, film formation is possible, and the flexibility of the insulating film is controlled to be low, so that the partial discharge start voltage of the insulating wire is reduced. It was improved and it was confirmed that flexibility was also excellent.

On the other hand, in Comparative Example 1, it was confirmed that the molar ratio of the first diamine compound and the second diamine compound exceeded the standard, and the heat resistance was significantly lowered. It was confirmed that the partial discharge start voltage decreased due to the increase, and the flexibility decreased.

In addition, in Comparative Examples 3 and 4, film formation was not possible because the content of the first diamine compound was excessively low, and in Comparative Example 5, the conventional polyamidiimide resin was applied to greatly increase the dielectric constant, so that the partial discharge initiation voltage was greatly reduced, and It was also confirmed that it was greatly degraded.

Although the present specification has been described with reference to preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention within the scope not departing from the spirit and scope of the present invention described in the claims described below. You will be able to do it. Therefore, if the modified implementation basically includes the elements of the claims of the present invention, all should be considered to be included in the technical scope of the present invention.

Claims (11)

1. As a composition for an insulating film,

   Including a polyimide resin formed through polymerization of a dianhydride compound and a diamine compound,

   The dianhydride compound includes a tetracarboxylic dianhydride or an isomer thereof,

   The diamine compound includes a first diamine compound and a second diamine compound,

   The first diamine compound is 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 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 -Consisting of bis(4-aminophenyl)fluorene (FDA), 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-bis(4-aminophenyl)sulfide and isomers thereof It contains at least one selected from the group,

   The second diamine compound comprises at least one selected from the group consisting of 1,4-diaminobenzene, 2,4-diaminotoluene, and isomers thereof,

   Composition for insulating film.
2. The method of claim 1,

   The molar ratio of the first diamine compound and the second diamine compound is greater than 50:50 and 95:5 or less.
3. The method according to claim 1 or 2,

   The tetracarboxylic dianhydride is at least one selected from the group consisting of pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), and isomers thereof. It characterized in that it comprises a, the composition for an insulating film.
4. The method of claim 3,

   The tetracarboxylic dianhydride has a mole of 30:70 or more and 70:30 or less of the pyromellitic dianhydride (PMDA) and 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) The composition for an insulating film, characterized in that mixed in a ratio.
5. The method according to claim 1 or 2,

   The polyimide resin is characterized in that it has a molecular structure of the following formula (1), an insulating film composition.

   [Formula 1]

   

   In Formula 1,

   n is 5 to 200.
6. The method according to claim 1 or 2,

   The polyimide resin is characterized in that the number average molecular weight (Mn) of 10,000 to 200,000, an insulating film composition.
7. The method according to claim 1 or 2,

   N-methyl-2-pyrrolidone (NMP), γ-butyrolactone, N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethylimidazolidinone (DMI), A composition for an insulating coating comprising at least one solvent selected from the group consisting of cyclohexanone, methylcyclohexanone and aromatic alkyl benzenes.
8. Conductor; And

   An insulated wire formed on the surface of the conductor and comprising an insulating film formed from the composition for an insulating film according to claim 1 or 2.
9. The method of claim 8,

   The insulating film is formed on the surface of the conductor and includes a first insulating film containing at least one resin selected from the group consisting of polyimide resin, polyamideimide resin, and polyesterimide resin; And

   An insulated wire comprising a second insulating film formed on the first insulating film and formed from the composition for an insulating film of claim 1 or 2.
10. The method of claim 9,

    Insulated wire, characterized in that the thickness of the second insulating film is 85% or more of the total thickness of the insulating film.
11. The method of claim 10,

    An insulated wire, characterized in that it further comprises at least one layer selected from the group consisting of an adhesion-improving layer formed on the surface of the conductor, a lubricating layer formed on the surface of the insulating film or the surface of the second insulating film, and a highly flexible layer.

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