JPH09227650A - Electrical insulating resin composition and enamel wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrical insulating resin compsn. which, even when baking in a thick coating form, can provide an excellent appearance, can be baked on a fine wire, and can offer an enamel wire possessing excellent soldability, heat resistance, and thermal shock resistance. SOLUTION: This electrical insulating resin compsn. comprises: (a) a polyester resin having an imide bond in its molecule, (b) a stabilized isocyanate, and (c) a dibasic acid diester represented by the formula (wherein R1 represents a 1-18C alkyl, a cycloalkyl, or aralkyl group; R2 represents a divalent arom. group; and R3 represents a 2-18C alkylene group, provided that the total number of carbon atoms in the molecule is in the range of from 10 to 32). The enamel wire comprises this electrical insulating resin compsn. applied and baked directly or through other insulator onto a conductor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for electrical insulation, and more specifically, it has a good appearance even when the coating film is thick, and is excellent in solderability, heat resistance and thermal shock resistance. The present invention relates to a resin composition for electrical insulation and an enamel wire using the same.

[0002]

2. Description of the Related Art Conventionally, polyurethane wire is known as an enameled wire having solderability, but its heat resistance is classified into Class A to Class E, and is used for applications requiring heat resistance of Class B or higher. It had the drawback that it could not be used. Recently, in order to improve this drawback, a resin composition containing a polyester resin having an imide group in the molecule and a stabilized isocyanate has been proposed and used for B-type insulation. However, although this resin composition is improved in heat resistance category B, it has a defect that when the coating is thickly baked, the coating is inferior in appearance due to particles, foaming, rough skin and the like. A method of adding a polymer resin such as a nylon resin, a phenoxy resin, an epoxy resin, or a polyester resin to a resin composition in order to improve the appearance of an enamel wire is known, but these resins are added to the resin composition. However, if the coating is thickly baked, there is no effect and the solderability is inferior.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, has an excellent appearance even when a coating is thickened and baked, and can be baked into a fine wire, and has solderability and heat resistance. The present invention provides a resin composition for electrical insulation, which can obtain an enamel wire excellent in heat resistance and thermal shock resistance, and an enamel wire using the same.

[0004]

The present invention provides (a) a polyester resin having an imide bond in the molecule, (b) a stabilized isocyanate, and (c) a general formula (I).

Embedded image (However, R ₁ is an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group or an aralkyl group, R ₂ is a divalent aromatic group,
R ₃ means an alkylene group having 2 to 18 carbon atoms, and the total number of carbon atoms in the molecule is in the range of 10 to 32), and relates to a resin composition for electrical insulation containing a dibasic acid diester represented by the formula: . Further, in the present invention, the content of the above (c) is 0.05 to 5. 5 with respect to the total amount of the above (a) and (b).
The present invention relates to the resin composition for electrical insulation, which is 0% by weight. The present invention also relates to an enamel wire obtained by applying the above-mentioned resin composition for electrical insulation onto a conductor directly or via another insulator and baking the resin composition.

The polyester resin (a) containing an imide bond in the molecule used in the present invention is obtained by the reaction of an acid component and an alcohol component. Since the imide bond is introduced into the resin, the acid component As a part of the general formula (II)

Embedded image (However, R in the formula means a divalent organic group.) It can be produced using an imidodicarboxylic acid.

The imidodicarboxylic acid represented by the general formula (II) can be obtained by reacting 2 mol of trimellitic anhydride with 1 mol of diamine. Examples of the diamine include 4,4′-diaminodiphenylmethane and m
-Phenylenediamine, p-phenylenediamine, 1,
4-diaminonaphthalene, 4,4'-diaminodiphenyl ether, hexamethylenediamine, diaminodiphenyl sulfone and the like can be mentioned. In the present invention, diisocyanates corresponding to the above diamines may be used in place of these diamines, and the production method thereof is not particularly limited. From the viewpoint of solderability, heat resistance and thermal shock resistance of the final composition, the amount of the imidodicarboxylic acid represented by the general formula (II) is within the range of 5 to 50 equivalent% with respect to all acid components. Is preferable, and it is particularly preferable to be in the range of 10 to 30 equivalent%. If the amount of this imidodicarboxylic acid is too small, the heat resistance tends to decrease, and if it is too large, the flexibility tends to decrease.

As an acid component other than the above imidodicarboxylic acid, terephthalic acid or a lower alkyl ester thereof, for example, dimethyl terephthalate, monomethyl terephthalate, terephthalic acid diester and the like are used. Further, compounds commonly used for polyester varnish for enameled wire, for example, isophthalic acid, adipic acid, phthalic acid, sebacic acid and the like can also be used.

The alcohol component used for producing the polyester resin having an imide bond in the molecule is
For example, ethylene glycol, propylene glycol,
Diethylene glycol, neopentyl glycol, 1,
Diols such as 3-butanediol and 1,4-butanediol, triols such as glycerin, trimethylolpropane, hexanetriol, and tris- (2-hydroxyethyl) isocyanurate are used. These acid components and alcohol components may be used alone or in combination of two or more. It is preferable to react all alcohol components in excess with respect to all acid components in an equivalent amount. This is because the hydroxyl group remains in the molecular chain of the polyester resin having an imide bond in the molecule, and this reacts with the stabilized isocyanate during baking to form a urethane bond. Further, the equivalent ratio of the total alcohol component and the total acid component (total alcohol component / total acid component) is preferably 1.3 to 2.5 from the viewpoint of solderability and heat resistance,
1.6-2.4 are more preferable.

The polyester resin (a) having an imide bond in the molecule is synthesized by reacting the acid component and the alcohol component in the presence of an esterification catalyst with heating at a temperature of 170 to 250 ° C. Be seen. Examples of the esterification catalyst used at this time include tetrabutyl titanate, lead acetate, dibutyltin laurate, zinc naphthenate, and the like. The imidodicarboxylic acid may be preliminarily synthesized, and the components of the diamine and trimellitic anhydride, which become the imidic acid, are mixed and heated at the same time as the other acid component and the alcohol component to effect imidization and esterification. You may go at the same time. At this time, the compounding amount of the diamine and trimellitic anhydride is an amount corresponding to the compounding amount of the imidodicarboxylic acid. Synthesis of polyester resin having an imide bond in the molecule, for example, because of high viscosity at the time of synthesis, phenol, cresol,
It is preferably carried out in the coexistence of a phenolic solvent such as xylenol.

As the stabilized polyisocyanate (b) used in the present invention, tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, diphenyl sulfone diisocyanate, triphenyl methane diisocyanate, hexamethylene diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, 3-isocyanate ethyl-3,
5,5-trimethylcyclohexyl isocyanate, 3
-Isocyanate ethyl-3,5,5-triethylcyclohexyl isocyanate, diphenylpropane diisocyanate, phenylene diisocyanate, cyclohexylylene diisocyanate, 3,3'-diisocyanate dipropyl ether, triphenylmethane triisocyanate, diphenyl ether-4,4 Phenols such as ′ -diisocyanate, phenols such as xylenol, oximes, imides, mercaptans, alcohols, ε-caprolactam, ethyleneimine, α-pyrrolidone, diethyl malonate, sodium hydrogen sulfite, boric acid, etc. There are things that have been blocked in. These may be used alone or in combination of two or more. Furthermore, a compound obtained from 4,4′-diphenylmethane diisocyanate and xylenol (Millionate MS-5 manufactured by Nippon Polyurethane Industry Co., Ltd.)
0), 4,4'-diphenylmethane diisocyanate,
A compound obtained from an aliphatic polyol and phenols (Coronate 2503 manufactured by Nippon Polyurethane Industry Co., Ltd.),
Examples thereof include compounds obtained from tolylene diisocyanate, aliphatic polyols and phenols (Dismoder AP stable, manufactured by Bayer).

The mixing ratio of the polyester resin (a) having an imide bond in the molecule and the stabilized isocyanate (b) is 100% from the viewpoint of solderability and heat resistance of the enamel wire. The range of 100 to 1000 parts by weight of the stabilized isocyanate (b) is preferable, and the range of 150 to 500 parts by weight is more preferable.

The dibasic acid diester used in the present invention is a compound represented by the above general formula (I). When the carbon number of R ₁ and R _{3 in} the general formula (I) exceeds 18, the heat resistance tends to decrease, and the preferable carbon number is 14 or less. Further, R ₁ and R ₃ may have a branch. Further, the total carbon number of the dibasic acid diester represented by the general formula (I) is in the range of 10 to 32 in view of heat resistance. Examples of the dibasic acid diester represented by the general formula (I) include acids such as phthalic anhydride, isophthalic acid, terephthalic acid, 3-methyl-phthalic anhydride, 4-methyl-phthalic anhydride, and butanol. , Hexanol, 2-ethylhexyl alcohol, n-octanol, and other monohydric alcohols are mixed and heated to form a monoester, and an epoxide such as ethylene oxide or propylene oxide is subjected to an addition reaction in the presence of a base catalyst to easily produce it. be able to. Examples of the above dibasic acid diester include 2-ethylhexyl-2-hydroxyethyl phthalate and 2
-Ethylhexyl-2-hydroxyoctyl phthalate and the like.

A resin composition for electrical insulation according to the present invention comprises a dibasic acid diester (c) represented by the general formula (I), a polyester resin (a) having an imide bond in the molecule and a stabilized isocyanate ( 0.05 to the total amount of b)
It is obtained by blending at a ratio of 5.0% by weight, preferably 0.05 to 2.0% by weight. If the addition amount is too small, the appearance of the baking line will not be improved, and if it is too large, the heat resistance will tend to be reduced.

The resin composition for electrical insulation according to the present invention comprises a polyester resin (a) and a stabilized isocyanate (b).
And the above dibasic acid diester (c) are dissolved in a solvent to adjust the viscosity to an appropriate level. Examples of the solvent used at this time include phenol, cresol, xylenol, cellosolves, xylene and the like. Moreover, you may add an organometallic compound to the resin composition for electrical insulation of this invention as needed. Examples of the organometallic compound include metal salts such as zinc naphthenate and manganese naphthenate.

[0015]

EXAMPLES The present invention will be described in more detail with reference to Examples. In addition,% in the following examples means weight%.

Example 1 In a four-necked flask equipped with a thermometer, a stirrer and a condenser, 99 g of 4,4'-diaminodiphenylmethane (1.
0 mol), 192 g (2.0 mol) of trimellitic anhydride, 291 g (3.0 mol) of dimethyl terephthalate,
Add 93 g (3.0 mol) of ethylene glycol, 92 g (3.0 mol) of glycerin, 217 g of cresol and 3.8 g of tetrabutyl titanate, and add 17 g in a nitrogen stream.
The temperature was raised to 0 ° C. and the reaction was performed for 60 minutes. Then, the obtained solution was heated to 210 ° C. and reacted for 3 hours. further,
To this solution, 436 g of cresol was added, and the nonvolatile content was 50%.
A polyester resin solution having an imide bond in the molecule was obtained. Coronate 2503 (stabilized isocyanate compound manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to 100 g of a polyester resin solution having an imide bond in the obtained molecule.
25 g, 0.175 g of 2-ethylhexyl-2-hydroxyethyl phthalate, 265 g of cresol and 1.5 g of zinc naphthenate were added and mixed at room temperature for 30 minutes to obtain a resin composition of the present invention.

Example 2 100 g of the polyester resin solution having an imide bond in the molecule obtained in Example 1 was added to Coronate 25031.
25 g, 2-ethylhexyl-2-hydroxyoctyl phthalate 1.75 g, cresol 265 g and zinc naphthenate 1.5 g were added and mixed at room temperature for 30 minutes to obtain a resin composition of the present invention.

Comparative Example 1 100 g of the polyester resin solution having an imide bond in the molecule obtained in Example 1 was added to Coronate 25031.
25 g, 260 g cresol and zinc naphthenate 1.
5 g was added and mixed at room temperature for 30 minutes to obtain a resin composition.

Comparative Example 2 A varnish for general-purpose polyurethane insulated wire WD-437 (manufactured by Hitachi Chemical Co., Ltd., a polyurethane resin composition using a polyester resin having no imide bond in the molecule) is used as Comparative Example 2.

<Test Example> Examples 1 and 2 and Comparative Examples 1 to 1
An enamel wire is produced using the resin composition obtained in 2,
The appearance and characteristics of the enamel wire were examined. (1) Appearance evaluation of enameled wire A copper wire having a diameter of 0.07 mm was baked under the following conditions while changing the coating thickness, and the appearance was visually observed. Table 1 shows the results. The baking conditions are as follows. Baking furnace: Horizontal furnace Furnace temperature: Inlet / outlet = 330 ° C / 380 ° C Linear velocity: 240 m / min Coating method: Felt 7 times drawing

[0021]

[Table 1]

From the results shown in Table 1, the resin composition of the present invention is
It is shown that the appearance is better than those of Comparative Examples 1 and 2.

(2) Evaluation of characteristics of enameled wire Under the same conditions as in (1), a copper wire having a diameter of 0.4 mm was baked and various characteristics were evaluated. The results are shown in Table 2. The test items in Table 2 were evaluated according to JIS C 3003 5-19. Regarding the breakdown voltage after heat deterioration, see JIS C.
Twisted wire manufactured according to 3003
After leaving it in the constant temperature bath of No. 168 for 168 hours, the dielectric breakdown voltage was measured.

[0024]

[Table 2]

From the results shown in Table 2, when the resin composition of the present invention is used, the thermal shock resistance and the dielectric breakdown voltage after thermal deterioration are higher than those of the conventional general-purpose polyurethane insulated wire (Comparative Example 2). It is shown that the excellent heat retention and softening resistance are excellent, and the characteristics are not deteriorated as compared with the conventional heat-resistant urethane wire of Comparative Example 1.

[0026]

According to the resin composition for electric insulation according to claim 1 or 2, the appearance is good even if the film is thickened, the heat resistance and the softening resistance are excellent, the solderability is excellent, and the thermal shock resistance is high. It is possible to produce an enameled wire having excellent properties, and the enameled wire according to claim 3 has such an excellent effect.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C09D 167/02 PLB C09D 167/02 PLB 175/04 PHN 175/04 PHN H01B 3/30 H01B 3 / 30 M

Claims (3)

[Claims] 1. A polyester resin having (a) an imide bond in the molecule, (b) a stabilized isocyanate, and (c) a general formula (I): (However, R ₁ is an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group or an aralkyl group, R ₂ is a divalent aromatic group,
R ₃ denotes an alkylene group having 2 to 18 carbon atoms, the total number of carbon atoms electrical insulating resin composition comprising a dibasic acid diester represented by to) a range of 10 to 32 in the molecule. 2. The resin composition for electrical insulation according to claim 1, wherein the content of (c) is 0.05 to 5.0% by weight based on the total amount of (a) and (b). 3. An enameled wire obtained by applying the electrical insulating resin composition according to claim 1 or 2 onto a conductor directly or via another insulating material, and baking it.