JP2003346558A - Resin composition for electric insulation and enameled wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for electric insulation, together with a enameled wire, capable of forming a coat which is excellent in adhesion to a conductor, wear resistance, and adhesion after thermal gradation while mechanical characteristics, heat resistance, flexibility, and electric insulation characteristics which are required for the enameled wire are maintained. <P>SOLUTION: The resin composition for electric insulation comprises (A) a polyester imide resin having isocyanurate ring in molecular chain and (B) tetrazole represented by a general expression (1) [R<SB>1</SB>=H, NH2, CH3, SH, Ar (aromatic ring), R<SB>2</SB>=H, CH3, Ar (aromatic ring)]. The resin composition for electric insulation is coated on a conductor and then baked to provide an enameled wire. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin composition for electrical insulation and an enameled wire using the same.

[0002]

2. Description of the Related Art Hitherto, as an insulated wire having heat resistance, a polyimide wire, a polyamideimide wire and a polyesterimide wire have been known. Among them, for example, from the viewpoint of the balance between properties and price, polyester imide resin in which an imide bond and an isocyanurate ring are introduced into a molecular chain using tris (2-hydroxyethyl) isocyanurate (hereinafter abbreviated as THEIC). Is used in a relatively large amount.

On the other hand, in the recent assembly process of electrical equipment, high-speed winding work by a machine is performed, and severe stress such as elongation, abrasion and bending is applied to the enameled wire. It is getting severer every year. Therefore, the enameled wire is required to have high adhesion and abrasion resistance between the conductor and the coating.
The adhesion of the polyesterimide varnish using C was insufficient for the requirement. As means for improving the adhesion between a polyesterimide varnish and a conductor using THEIC, JP-A-2-58567 and JP-A-7-316425 disclose the incorporation of a thiol compound into a polyesterimide varnish. ing. However, when this method is used, although the adhesion between the conductor and the coating is improved, there is a problem that the adhesion between the conductor and the coating after the enameled wire is thermally deteriorated is extremely reduced.

[0004]

SUMMARY OF THE INVENTION The present invention provides an enameled wire having various properties such as mechanical properties, heat resistance, flexibility, and electrical insulation properties, while maintaining adhesion and abrasion resistance with a conductor. An object of the present invention is to provide a resin composition for electrical insulation capable of forming a film having excellent adhesion after thermal degradation and an enameled wire using the same.

[0005]

The present invention provides (A) a polyesterimide resin having an isocyanurate ring in the molecular chain, and (B) a general formula (1)

[0006]

Embedded image [R1 = H, NH2, CH3, SH, Ar (aromatic ring) R2 = H, CH3, Ar (aromatic ring)] An electric insulating resin composition containing a tetrazole represented by the formula: Things. The present invention also provides an electrically insulating resin composition containing 0.01 to 1 part by weight of the tetrazole (B) based on 100 parts by weight of the polyesterimide resin (A).
The present invention also provides an enameled wire obtained by applying the resin composition for electrical insulation on a conductor and baking the conductor.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The polyesterimide resin having an isocyanurate ring in the molecule in the present invention is obtained by reacting an acid component with an alcohol component. Here, the isocyanurate ring has the following structure.

[0008]

Embedded image

The polyesterimide resin used in the present invention has a general formula (2) as a part of the acid component.

Embedded image [Wherein, R1 represents a trivalent organic group such as a residue of a tricarboxylic acid, and R2 represents a divalent organic group such as a residue of a diamine].

As the imidodicarboxylic acid represented by the general formula (2), for example, imidodicarboxylic acid obtained by reacting 2 moles of tricarboxylic anhydride with 1 mole of diamine (see Japanese Patent Publication No. 51-40113) )
Is mentioned. Instead of reacting the diamine with the tricarboxylic anhydride in advance and using it as the imidodicarboxylic acid, the diamine and the tricarboxylic anhydride may be added during the production of the polyesterimide to form a residue of the imidodicarboxylic acid. As tricarboxylic anhydride,
There are trimellitic anhydride, 3,4,4'-benzophenone tricarboxylic anhydride, 3,4,4'-biphenyltricarboxylic anhydride and the like, with trimellitic anhydride being preferred. As the diamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether,
m-phenylenediamine, p-phenylenediamine,
1,4-diaminonaphthalene, hexamethylenediamine, diaminodiphenylsulfone and the like are used.

The amount of imidodicarboxylic acid to be used is preferably in the range of 15 to 65 equivalent% of the total acid component.
It is more preferable that the content be in the range of ６０60 equivalent%. If the amount of the imidodicarboxylic acid is too small, the heat resistance tends to be inferior, and if it is too large, the flexibility and the appearance of the enameled wire may decrease. As the acid component other than the above imidodicarboxylic acid, terephthalic acid or a lower alkyl ester thereof, for example, terephthalic acid diester such as monomethyl terephthalate and lower alkyl diester of terephthalic acid, for example, dimethyl terephthalate and the like are used. Further, compounds commonly used in polyester imide varnish for enameled wire, for example, isophthalic acid, adipic acid,
Phthalic acid, sebacic acid and the like can also be used.

As the alcohol component used in the production of a polyesterimide resin having an isocyanurate ring in the molecular chain, it is preferable to use an alcohol component having an isocyanurate ring, such as tris (hydroxymethyl) isocyanurate or tris (2- Isocyanurate compounds having three hydroxyl groups, such as (hydroxyethyl) isocyanurate and tris (3-hydroxypropyl) isocyanurate, are more preferred, and tris (2-hydroxyethyl) isocyanurate is the most preferred. The amount of the isocyanurate compound used is preferably in the range of 30 to 90 equivalent% of the total alcohol component, and more preferably in the range of 40 to 80 equivalent%. If the amount of the isocyanurate compound is too small, the heat resistance tends to be poor, and if it is too large, the flexibility tends to decrease.

Examples of the alcohol component other than the alcohol component having an isocyanurate ring include diols such as ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, 1,3-butanediol, and 1,4-butanediol. , Glycerin, trimethylolpropane, hexanetriol, and other triols. These acid components and alcohol components are used alone or in combination of two or more. From the viewpoint of flexibility and heat resistance, the mixing ratio of the alcohol component and the acid component is preferably such that the equivalent ratio of the hydroxyl group to the carboxyl group is 1.3 to 2.5,
More preferably, it is 1.5 to 2.2. If the equivalent ratio of the hydroxyl group to the carboxyl group is greater than 2.5, the flexibility tends to decrease, and if it is less than 1.3, the heat resistance tends to decrease.

In the synthesis of the polyesterimide resin used in the present invention, for example, the acid component and the alcohol component are reacted at a temperature of 160 to 250 ° C., preferably 170 to 250 ° C. and 3 to 15 in the presence of an esterification catalyst. The reaction is carried out by heating for a time, preferably 5 to 10 hours. At this time, examples of the esterification catalyst used include tetrabutyl titanate, lead acetate, dibutyltin laurate, zinc naphthenate and the like. The reaction is
It is preferable to carry out under an inert atmosphere such as nitrogen gas. The imidodicarboxylic acid may be one synthesized in advance, or the imidization and esterification by mixing and heating the diamine and trimellitic anhydride imide acid components simultaneously with other acid components and alcohol components. May be performed simultaneously. At this time, the amount of the diamine and trimellitic anhydride is preferably an amount corresponding to the amount of the imidodicarboxylic acid.

Further, since the viscosity at the time of synthesis is high, for example,
The synthesis is preferably performed in the presence of a phenolic solvent such as phenol, cresol, and xylenol. The tetrazole used in the present invention is represented by the general formula (1). Among the tetrazoles represented by the general formula (1), more specifically preferred compounds are
-Methyl-5-mercapto-1H-tetrazole, 5-
Examples thereof include phenyl-1H-tetrazole and 1-phenyl-5-mercapto-1H-tetrazole. The resin composition for electrical insulation of the present invention is obtained by blending tetrazole with the polyesterimide resin as described above.

The amount of the tetrazole is preferably 0.01 to 1 part by weight, more preferably 0.05 to 0.8 part by weight, based on 100 parts by weight of the polyesterimide resin. When the amount of the tetrazole is less than 0.01 part by weight, the effect of improving the adhesion is small, and when the amount of the tetrazole exceeds 1 part by weight, the adhesion after heat-degrading the enameled wire tends to decrease. To the resin composition for electrical insulation of the present invention, a curing agent such as tetrabutyl titanate, a metal salt of an organic acid, for example, a zinc salt, a lead salt, a manganese salt or the like, may be added as necessary. Can be. The amount of the curing agent is preferably 3 to 10% by weight based on the polyesterimide resin, and the amount of the metal salt of the organic acid is preferably 0.1 to 1% by weight based on the polyesterimide resin.
Is preferred.

The resin composition for electrical insulation of the present invention can be used after being dissolved in a solvent and adjusted to an appropriate viscosity.
As the solvent used at this time, for example, phenol,
A solvent having good solubility with the polyesterimide resin, such as cresol, xylenol, cellosolves, and xylene, is used. The resin composition for electrical insulation of the present invention thus obtained is coated on a conductor such as a copper wire and baked to form an enameled wire having excellent wear resistance, adhesion and adhesion after thermal degradation. Can be. Except for using the composition of the present invention, the method for producing an enameled wire is not particularly limited, and can be according to a conventional method. For example, the resin composition for electric insulation of the present invention is applied on a conductor, and is applied at 350 to 550 ° C, preferably 400 to 500 ° C for 1 minute to 5 minutes, preferably 2 to 4 minutes.
A method of forming a film having a desired thickness on a conductor by repeating the step of heating and baking for a plurality of minutes for a plurality of times is exemplified. The thickness of the film finally formed is not particularly limited, but is usually preferably 0.02 to 0.08 mm, and 0.03 to 0.08 mm.
More preferably, it is 6 mm. The enameled wire of the present invention obtained in this manner does not deteriorate in various properties such as flexibility.

[0018]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, “%” means “% by weight” unless otherwise specified. Example 1 (1) Preparation of Polyesterimide Resin Liquid In a four-necked flask equipped with a thermometer, a stirrer and a condenser,
4,4'-diaminodiphenylmethane 158.4 g
(1.6 equivalents), 307.2 g of trimellitic anhydride
(3.2 equivalents), 232.8 g of dimethyl terephthalate
(2.4 equivalents), 375.8 g (4.32 equivalents) of tris (2-hydroxyethyl) isocyanurate, 89.3 g (2.88 equivalents) of ethylene glycol, 385 g of cresol, and 1.16 g of tetrabutyl titanate
Was added, and the temperature was raised from room temperature to 170 ° C. for 1 hour in a nitrogen stream to cause a reaction for 3 hours. The resulting solution is then
The temperature was raised to ° C., and the reaction was carried out for 6 hours to synthesize a polyesterimide. 920 g of cresol was added to the obtained resin solution, and 41.2 g of tetrabutyl titanate was added to obtain a polyesterimide resin solution having a nonvolatile content of 42%.

(2) Preparation of Resin Composition for Electrical Insulation Polyesterimide resin liquid 100 obtained in (1) above
g to 1-methyl-5-mercapto-1H-tetrazole 0.084 g (0.2% based on the solid content of the resin solution)
Was added to obtain a resin composition for electrical insulation. The content of tetrabutyl titanate (curing agent) in the resin composition for electric insulation was 4% based on the solid content in the polyesterimide resin liquid. (Example 2) In Example 1 (2), 1-methyl-5
Example 1 except that instead of -mercapto-1H-tetrazole, 0.084 g (0.2% based on the solid content of the resin solution) of 5-phenyl-1H-tetrazole was added.
It went according to. (Example 3) In Example 1 (2), 1-methyl-5
-Instead of mercapto-1H-tetrazole, 1-phenyl-5-mercapto-1H-tetrazole 0.0
The procedure was performed in the same manner as in Example 1 except that 84 g (0.2% based on the solid content of the resin solution) was added.

Comparative Example 1 The polyester imide resin liquid of Example 1 (1) was used as it was. (Comparative Example 2) To 100 g of the polyesterimide resin liquid obtained in Example 1 (1) was added 0.084 g of 5-amino-1,3,4-thiadiazole-2-thiol (0.1% based on the solid content of the resin liquid). 2%) to obtain a resin composition for electrical insulation.

(Test Examples) Examples 1-3 and Comparative Examples 1-4
Was applied to a copper wire having a diameter of 1.0 mm according to the following baking conditions, and baked at a wire speed of 14 m / min to produce an enameled wire. (Coating and baking conditions) Baking furnace: hot-air vertical furnace (furnace length: 5.5 m) Furnace temperature: Inlet / outlet = 320 ° C / 430 ° C Coating method: Enamel wire through which the resin composition has passed is squeezed with a die and baked The procedure of passing through the furnace is performed seven times. The diameter of the dies from the first time to the seventh time is 1.05 mm, 1.06 mm.
mm, 1.07mm, 1.08mm, 1.09mm,
It was changed to 1.10 mm and 1.11 mm. Further, the adhesion test of the obtained enameled wire was evaluated according to the following method, and other general characteristics (flexibility, thermal shock resistance, dielectric breakdown voltage, softening resistance) were measured according to JIS C3003. Table 1 shows the results. [Adhesion test] The adhesion is evaluated by a rapid cutting method. That is, both ends of an enameled wire having an appropriate length are fixed, and the wire is cut at a tensile speed of about 4 m / s with a mark length of 250 mm. The length (mm) of the exposed portion (two locations) of the conductor at the cut location is represented as, for example, 1.0 + 1.0. Similarly, the length (portion of the coating) where the coating is peeled off from the conductor is represented as 5.0 + 5.0. This is performed at the initial stage of the enameled wire, after 200 ° C./6 hour deterioration.

In the measurement of the adhesion, the smaller the value, the better the adhesion between the film and the conductor. From the results shown in Table 1, the enameled wires prepared using the resin compositions obtained in Examples 1 to 3 showed abrasion resistance and adhesion (initial and 20%) as compared with those obtained in Comparative Examples.
(After 0 ° C./6 hours), and the characteristics such as flexibility were the same.

[0023]

[Table 1]

[0024]

EFFECT OF THE INVENTION The use of the oil composition for electrical insulation containing a polyesterimide having an isocyanurate bond in the molecular chain according to the present invention provides excellent abrasion resistance and adhesion (initial and after 200 ° C./6 hours). An enameled wire in which various properties such as flexibility are not reduced is obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01B 7/02 H01B 7/02 A

Claims (3)

[Claims] 1. A polyester imide resin having (A) an isocyanurate ring in a molecular chain, and (B) a general formula (1) shown below. [R1 = H, NH2, CH3, SH, Ar (aromatic ring) R2 = H, CH3, Ar (aromatic ring)] A resin composition for electrical insulation containing a tetrazole represented by the following formula: 2. The resin composition for electrical insulation according to claim 1, which contains 0.01 to 1 part by weight of tetrazole (B) based on 100 parts by weight of polyesterimide resin (A). 3. An enameled wire obtained by applying the resin composition for electrical insulation according to claim 1 or 2 on a conductor and baking it.