JP2001026703A - Resin composition for electric insulation and enamel wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject electric insulation resin composition that can form a coating layer having excellent properties, for example, flexibility or the like, further having high thermal shock resistance on the conductor and is useful for producing enamel wires by using a specific polyester resin and a metal acetylacetonate. SOLUTION: This resin composition for electric insulation comprises (A) a polyester resin bearing imide bonds in the molecule and (B) a metal acetylacetonate salt. In a preferred embodiment, the component B is formulated to the component A in an amount of 0.01-2 pts.wt., particularly 0.05-1.5 pts.wt., per 100 pts.wt. of the component A. The component A is prepared from an acid component including 3-20 equivalent % of imide-dicarboxylic acid in the whole acid components and the alcohol components, or from the acid components including a tricarboxylic anhydride and a diamine in the same equivalent of the imide-dicarboxylic acid, and the alcohol components. The number-average molecular weight of the component A is preferably 1,500-4,000.

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 Conventionally, polyamide-imide wires, polyimide wires and polyester-imide wires have been known as heat-resistant insulated wires. Among these wires, for example, tris (2-hydroxy) is preferred in view of the balance between characteristics and price. A relatively large amount of polyesterimide wire obtained by baking a polyesterimide resin using (ethyl) isocyanurate (hereinafter abbreviated as THEIC) has been used. On the other hand, varnishes for general-purpose enameled wires have relatively good balance of mechanical properties, electrical properties, heat resistance, etc.
Non-THEIC polyester varnishes that do not use C are often used.

[0003] With the recent miniaturization and weight reduction of electric equipment and diversification of use environments, the required performance of insulating materials used has been further enhanced. For such requests, non-TH
EIC polyester varnishes are excellent in flexibility and price, but are not satisfactory in heat resistance, particularly in thermal shock resistance. Therefore, in order to improve the thermal shock resistance of the non-THEIC polyester varnish, techniques such as increasing the imide component and increasing the molecular weight have been adopted. However, when these techniques are used, flexibility and the like are increased. There is a problem that various characteristics are reduced.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art mainly in non-THEIC polyester varnishes, has excellent properties such as flexibility on a conductor, and has thermal shock resistance. An object of the present invention is to provide a resin composition for electrical insulation capable of forming a film having excellent properties and an enameled wire using the composition.

[0005]

SUMMARY OF THE INVENTION The present invention relates to an electrically insulating resin composition comprising a polyester resin having an imide bond in a molecule and a metal salt of acetylacetone.
The present invention also relates to a resin composition for electrical insulation, comprising 0.01 to 2 parts by weight of the metal salt of acetylacetone described above with respect to 100 parts by weight of the polyester resin having an imide bond in the molecule.

In the present invention, it is also preferred that the polyester resin having an imide bond in the molecule is produced by using an acid component containing 3 to 20 equivalent% of imidodicarboxylic acid in the total acid component and an alcohol component. Alternatively, the present invention relates to a resin composition for electrical insulation, which is produced by using an acid component containing tricarboxylic anhydride and a diamine as raw materials and an alcohol component as imidodicarboxylic acids in the same ratio as described above. The present invention also relates to an enameled wire obtained by applying the above-mentioned resin composition for electrical insulation on a conductor and baking the conductor.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a polyester resin having an imide bond in a molecule is obtained by a reaction between an acid component and an alcohol component. As a part of the general formula (I)

Embedded image (Wherein, R ¹ represents a trivalent organic group such as a residue of a tricarboxylic acid, and R ² represents a divalent organic group such as a residue of a diamine). Alternatively, tricarboxylic anhydride and diamine, which are the raw materials, are used.

As the imidodicarboxylic acid represented by the general formula (I), for example, imidodicarboxylic acid obtained by reacting 2 mol of tricarboxylic anhydride with 1 mol of diamine (Japanese Patent Publication No. 51-40113) Reference). Alternatively, a method in which a diamine and trimellitic anhydride, which are raw materials thereof, are added during the production of a polyester may be used without using the diamine and trimellitic anhydride in advance as an imidodicarboxylic acid.

The tricarboxylic anhydride includes trimellitic anhydride, 3,4,4'-benzophenone tricarboxylic anhydride, 3,4,4'-biphenyltricarboxylic anhydride and the like. Is 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.

In the polyester resin used in the present invention, the imidodicarboxylic acid is preferably used in a range of 3 to 20% by weight, more preferably 5 to 15% by weight of the total acid component. If the amount of the imidodicarboxylic acid is too small, the heat resistance tends to be inferior, and if it is too large, the crazing and the appearance of the enameled wire may decrease.

As the acid component other than the above-mentioned imide dicarboxylic acid, terephthalic acid or a lower alkyl ester thereof, for example, dimethyl terephthalate monomethyl terephthalate, terephthalic acid diester and the like are used. Compounds commonly used in polyester varnishes for enameled wires, for example, isophthalic acid, adipic acid, phthalic acid, sebacic acid and the like can also be used.

The alcohol component used in the production of the polyester resin includes diols such as ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, 1,3-butanediol and 1,4-butanediol. As triols, glycerin other than THEIC, trimethylolpropane, hexanetriol and the like are used. These acid components and alcohol components are used alone or in combination of two or more.

The mixing ratio of the alcohol component and the acid component is as follows:
From the viewpoint of flexibility and heat resistance, the equivalent ratio of the hydroxyl group to the carboxyl group is preferably from 1.3 to 1.6, and more preferably from 1.4 to 1.5. When the equivalent ratio of the hydroxyl group to the carboxyl group is large, the flexibility tends to decrease, and when it is small, the heat resistance tends to decrease.

The synthesis of the polyester resin used in the present invention is carried out, for example, by heating and reacting the above-mentioned acid component and alcohol component at a temperature of 170 to 250 ° C. in the presence of an esterification catalyst. At this time, examples of the esterification catalyst used include tetrabutyl titanate, lead acetate, dibutyltin laurate, zinc naphthenate and the like.

The imide dicarboxylic acid may be one synthesized in advance, or the imide acid of diamine and trimellitic anhydride may be mixed and heated at the same time as the other acid component and alcohol component to imidize and imidize. Esterification 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. In addition, since the viscosity at the time of synthesis is high, the synthesis is preferably performed in the coexistence of a phenol-based solvent such as phenol, cresol, and xylenol.

The molecular weight of the polyester resin is preferably from 1500 to 4000 in number average molecular weight. However, the number average molecular weight is measured by gel permeation chromatography using a standard polystyrene calibration curve,
The same applies to the following.

The metal salt of acetylacetone used in the present invention generally has the following general formula (II):

Embedded image [Wherein, M represents any one of Al, Cr, Co, Cu, and Fe, and n represents 2 or 3]. Examples of commercially available products include metal salts of acetylacetone manufactured by Wako Pure Chemical Industries, Ltd., and Nersem manufactured by Nippon Chemical Industry Co., Ltd.

The resin composition for electrical insulation of the present invention may contain 0.01 to 2.0 parts by weight of a metal salt of acetylacetone with respect to 100 parts by weight of a polyester resin having an imide bond in a molecule. Preferably, 0.05-1.
It is more preferable to mix at a ratio of 5 parts by weight. If the amount of acetylacetone metal salt is too small, the effect of improving thermal shock resistance is small, and if the amount of acetylacetone metal salt is too large,
The viscosity stability of the varnish tends to decrease.

The electric insulating resin composition of the present invention may further contain, if necessary, a curing agent such as tetrabutyl titanate or a metal salt of an organic acid (a zinc salt, a lead salt, a manganese salt, etc.) as an appearance improving agent. Can be added. The amount of the curing agent used is 3 to 10 with respect to 100 parts by weight of the polyester resin.
The amount of the metal salt of the organic acid is preferably 0.1 to 1 part by weight based on 100 parts by weight of the polyester resin.

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.
At this time, as a solvent used, for example, phenol,
A solvent having good solubility with cresol, xylenol, cellosolves, xylene and the like, that is, a polyester resin is used.

The resin composition for electrical insulation of the present invention is coated on a conductor such as a copper wire and baked to form an enameled wire having excellent thermal shock resistance. The method of application and baking may be a general method and is not particularly limited. The enameled wire obtained using the resin composition for electrical insulation of the present invention does not deteriorate in various properties such as flexibility.

[0022]

The present invention will be described in more detail with reference to the following examples. In the examples, “%” means “% by weight” unless otherwise specified. Example 1 (1) Preparation of polyester resin liquid In a four-necked flask equipped with a thermometer, a stirrer and a condenser, 39.6 g of 4,4'-diaminodiphenylmethane was added.
(0.4 equivalents), 76.8 g of trimellitic anhydride (0.
8 equivalents), 349.2 g of dimethyl terephthalate (3.6
Eq.), 73.0 g (2.38 eq.) Of glycerin, 99.8 g (3.22 eq.) Of ethylene glycol, 114 g of cresol and 0.64 g of tetrabutyl titanate, and heated from room temperature to 170 ° C. for 1 hour in a nitrogen stream. The temperature was raised to react for 2 hours. Then, the obtained solution was heated at 215 ° C.
And a reaction was carried out for 5 hours to synthesize a polyester having a number average molecular weight of about 2,000. 583 g of cresol was added to the obtained resin solution, and 26.4 g of tetrabutyl titanate was added.
And 25.3 g of zinc naphthenate (metal content 6%) were added to obtain a polyester resin liquid having a nonvolatile content of 40%.

(2) Preparation of Resin Composition for Electrical Insulation 100 g of the polyester resin liquid obtained in (1) above was added to
Acetylacetone copper salt [Nihon Kagaku Sangyo Co., Ltd., trade name Nasemu copper, chemical formula _{Cu (C 5 H 7 O 2} ) 2] 0.63g (1.
5%) to obtain a resin composition for electrical insulation.

Example 2 In Example 1 (2), acetylacetone chromium salt [Nasem chrome, trade name, manufactured by Nippon Kagaku Sangyo Co., Ltd., chemical formula: Cr (C ₅ H ₇ O ₂ ) ₂ ] instead of nasem copper. 63g
(1.5%), except that (1.5%) was added.

Comparative Example 1 The polyester resin liquid of Example 1 (1) was used as it was.

Comparative Example 2 A four-necked flask equipped with a thermometer, a stirrer and a condenser was charged with 79.2 g of 4,4'-diaminodiphenylmethane.
(0.8 equivalent), 153.6 g of trimellitic anhydride
(1.6 equivalents), 310.4 g of dimethyl terephthalate
(3.2 equivalents), 73.0 g (2.38 equivalents) of glycerin, 99.8 g (3.22 equivalents) of ethylene glycol, 126 g of cresol and 0.72 g of tetrabutyl titanate, and 1 hour from room temperature in a nitrogen stream. At 1
The temperature was raised to 70 ° C., and the reaction was performed for 3 hours. Then, the obtained solution was heated to 215 ° C. and reacted for 6 hours to synthesize a polyester having a number average molecular weight of about 2,000. To the obtained resin solution, 710 g of cresol was added, and 29.5 g of tetrabutyl titanate and zinc naphthenate (metal content: 6%) 2
By adding 9.2 g, a polyester resin liquid having a nonvolatile content of 40% was obtained.

Comparative Example 3 In a four-necked flask equipped with a thermometer, a stirrer and a condenser, 39.6 g of 4,4'-diaminodiphenylmethane was added.
(0.4 equivalents), 76.8 g of trimellitic anhydride (0.
8 equivalents), 349.2 g of dimethyl terephthalate (3.6
Eq.), 73.0 g (2.38 eq.) Of glycerin, 99.8 g (3.22 eq.) Of ethylene glycol, 114 g of cresol and 0.64 g of tetrabutyl titanate, and heated from room temperature to 170 ° C. for 1 hour in a nitrogen stream. The temperature was raised to react for 2 hours. Then, the obtained solution was heated at 215 ° C.
And a reaction was carried out for 8 hours to synthesize a polyester having a number average molecular weight of about 4000. 583 g of cresol was added to the obtained resin solution, and 26.4 g of tetrabutyl titanate and 25.3 g of zinc naphthenate (metal content: 6%) were added to obtain a polyester resin liquid having a nonvolatile content of 40%.

<Test Examples> Examples 1-2 and Comparative Examples 1-3
The resin composition obtained in the above 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 15 m / min.
An enameled wire was prepared.

[Coating / Baking Conditions] Baking furnace: hot-air vertical furnace (furnace length: 5.5 m) Furnace temperature: inlet / outlet = 320 ° C./430° C. The procedure of drawing and passing through a baking furnace is performed six times. The diameter of the first to sixth dies is 1.07mm, 1.09m
m, 1.11mm, 1.12mm, 1.13mm, 1.14mm
Was changed.

Further, the general properties (flexibility, dielectric breakdown voltage, softening resistance, thermal shock resistance) of the obtained enameled wire are determined according to JIS.
It measured according to C3003 and the result is shown in Table 1. In the measurement results of flexibility and thermal shock resistance,
A single diameter good means that cracks did not occur when wound tightly around a stainless steel rod having a diameter of 1.0 mm. Similarly, "double diameter good" means that no crack was generated when the enamel wire was stretched by 20% and wound around a stainless steel rod having a diameter of 2.0 mm without any gap, and one having a good diameter was used. This indicates that cracks are more likely to occur.

[0031]

[Table 1]

[0032]

By using the resin composition for electrical insulation according to the present invention, it is possible to provide an enameled wire which is excellent in thermal shock resistance and does not deteriorate in various properties such as flexibility.

Claims (4)

[Claims] 1. A resin composition for electrical insulation comprising a polyester resin having an imide bond in a molecule and a metal salt of acetylacetone. 2. The resin composition for electrical insulation according to claim 1, wherein 0.01 to 2 parts by weight of a metal salt of acetylacetone is mixed with 100 parts by weight of the polyester resin having an imide bond in the molecule. 3. The polyester resin having an imide bond in a molecule is produced by using an acid component containing 3 to 20 equivalent% of imidodicarboxylic acid in the total acid component and an alcohol component, or 3. The resin composition for electrical insulation according to claim 1, wherein the imidodicarboxylic acid having the same ratio is produced by using an acid component containing tricarboxylic anhydride and a diamine as raw materials and an alcohol component. 4. An enameled wire obtained by applying the resin composition for electrical insulation according to claim 1, 2 or 3 on a conductor and baking it.