JP2001064509A - Resin composition for electric insulation and insulated wire therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compsn. having solderability, good in thermal resistance and weatherability, especially, hydrolysis resistance by incorporating a polyester resin contg. an imide bond in a molecule, a stabilized isocyanate, and an isocyanurate compd. having an epoxy group. SOLUTION: This composition includes (A) a polyester resin having an imidodicarboxylic acid shown by the formula (wherein R is a bivalent org. group) to introduce an imide bond in the resin as a part of acid component in an amount of 10-30 eq.% of the total acid component, (B) stabilized isocyanate, e.g. tolylene diisocyanate, and (C) an isocyanurate compd. preferably having three epoxy groups, e.g. tris(2,3-epoxypropyl) isocyanurate. Compounding ratio used is 100-1,000 pts.wt. component B based on 100 pts.wt. component A. Component C is used in an amount of 0.5-10 pts.wt. based on 100 pts.wt. of the total of the component A and component B.

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 having excellent heat resistance and an insulated wire using the same.

[0002]

2. Description of the Related Art A terminal of an enameled wire wound on a motor, a transformer or the like is subjected to a process of connecting after peeling off an insulating film. It is often used in fields with low heat resistance. However, as a market demand, a demand for a polyurethane wire having higher heat resistance (B class or more) and excellent environmental resistance, particularly excellent hydrolysis resistance, is increasing.
Among the materials for polyurethane wire varnishes, it has been studied to improve the heat resistance by introducing a heat-resistant imide group into a polyester-based resin, in particular. Is not enough for market demand.

[0003]

An object of the present invention is to provide an insulating material having solderability, excellent heat resistance and superior environmental resistance, especially hydrolysis resistance, as compared with conventional polyurethane wires. An object of the present invention is to provide a resin composition capable of obtaining an electric wire and an insulated electric wire using the same.

[0004]

SUMMARY OF THE INVENTION The present invention provides an electric machine comprising (a) a polyester resin having an imide bond in the molecule, (b) a stabilized isocyanate, and (c) an isocyanurate compound having an epoxy group. The present invention relates to an insulating resin composition and an insulated wire obtained by applying the resin composition directly or via another insulating material on a conductor and baking the conductor.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The resin composition of the present invention contains the components (a) to (c) as described above.

The polyester resin having an imide bond in the molecule used as the component (a) is obtained by a reaction between an acid component and an alcohol component. As a part, the general formula (II)

[0007]

Embedded image [In the formula, R 'represents a divalent organic group.]

In the general formula (II), R ′ represents, for example, a diamine residue capable of forming an imide bond by reacting with an acid anhydride. R ′ is a hydrocarbon group having 1 to 20 carbon atoms or an ether bond of two or more of the hydrocarbon groups,
Examples thereof include a group bonded via a sulfone bond, a carbonyl bond, a thioether bond, and the like. Among them, a divalent aromatic hydrocarbon group having 6 to 14 carbon atoms, or two or more aromatic hydrocarbon groups A group bonded via an ether bond or a sulfone bond is preferred.

The imidodicarboxylic acid represented by the general formula (II) can be obtained by reacting 2 moles of trimellitic anhydride with 1 mole of a diamine as disclosed in, for example, Japanese Patent Publication No. 51-40113. Is obtained by Examples of the diamine include 4,4'-diaminodiphenylmethane, m-phenylenediamine, p-phenylenediamine, 1,4-diaminonaphthalene, 4,4'-diaminodiphenylether, hexamethylenediamine,
And diaminodiphenyl sulfone.

In order to obtain imidodicarboxylic acid, diisocyanates corresponding to the above-mentioned diamines may be used instead of these diamines.

The amount of the imidodicarboxylic acid represented by the general formula (II) is from 10 to 30 equivalent% of the total acid component in view of solderability, heat resistance and thermal shock resistance of the final composition.
Is preferable.

Examples of the acid component other than the imide dicarboxylic acid used in the polyester resin having an imide bond in the molecule include terephthalic acid or a lower alkyl ester thereof, for example, dimethyl terephthalate, monomethyl terephthalate, diethyl terephthalate and the like. Can be

Further, 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 of the polyester resin having an imide bond in the molecule includes, for example, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4- Examples thereof include diols such as butanediol, and triols such as glycerin, trimethylolpropane, hexanetriol, and tris- (2-hydroxyethyl) isocyanurate.

These acid components and alcohol components can be used alone or in combination of two or more. It is preferable that all alcohol components are reacted in excess with respect to all acid components in an equivalent amount. This is because a hydroxyl group is left in the molecular chain of the polyester resin having an imide bond in the molecule, and this is reacted with the stabilized isocyanate at the time of baking to generate a urethane bond.

From the viewpoint of solderability and heat resistance, the equivalent ratio of the total alcohol component / the total acid component is preferably from 1.3 to 2.5, and more preferably from 1.6 to 2.4. More preferred.

In the synthesis of the polyester resin having an imide bond in the molecule as the component (a), the acid component and the alcohol component are reacted at 170 ° C. to 2 ° C. in the presence of an esterification catalyst.
The reaction is performed by heating at a temperature of 50 ° C. Examples of the esterification catalyst used in this case include tetrabutyl titanate, lead acetate, dibutyltin laurate, zinc octenoate, zinc naphthenate, and the like.

The above-mentioned imide dicarboxylic acid may be a previously synthesized one, or a component to be an imide dicarboxylic acid such as diamine or trimellitic anhydride may be mixed and heated simultaneously with other acid components and alcohol components. Imidation and esterification may be performed simultaneously to synthesize a polyester resin having an imide bond.

The synthesis of a polyester resin having an imide bond in the molecule is preferably carried out in the presence of a phenolic solvent such as phenol, cresol, xylenol, etc., because of its high viscosity at the time of synthesis.

The stabilized isocyanate used as the component (b) in the resin composition of the present invention includes tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, diphenylsulfone diisocyanate, triphenylmethane diisocyanate, hexamethylene diisocyanate. 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 3-isocyanatoethyl-3,5,5-trimethylcyclohexyl isocyanate, 3-isocyanatoethyl-3,5,5
-Triethylcyclohexyl isocyanate, diphenylpropane diisocyanate, phenylene diisocyanate, cyclohexylene diisocyanate, 3,3'-
Diisocyanate dipropyl ether, triphenylmethane triisocyanate, diphenyl ether-4,
Polyisocyanates such as 4'-diisocyanate are converted to phenols such as phenol and xylenol, oximes,
Examples include imides, mercaptans, alcohols, ε-caprolactam, ethyleneimine, α-pyrrolidone, diethyl malonate, sodium bisulfite, boric acid, and the like. These can be used alone or
It can be used in combination of more than one kind.

Commercial products of such stabilized isocyanates include compounds obtained from 4,4'-diphenylmethane diisocyanate and xylenol (Millionate MS-50, trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.);
A compound obtained by adding trimethylolpropane to 4,4'-diphenylmethane diisocyanate and blocking the free isocyanate group with phenols (Coronate 250, trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.)
3) Compounds obtained by adding trimethylolpropane to tolylene diisocyanate and blocking the free isocyanate groups with phenols (manufactured by Bayer AG, trade name: Dismodule AP Staple).

The mixing ratio of the polyester resin having an imide bond in the molecule as the component (a) and the stabilized isocyanate as the component (b) is determined in consideration of the solderability and heat resistance of the insulated wire. The content of the stabilized isocyanate is preferably in the range of 100 to 1,000 parts by weight, more preferably in the range of 150 to 500 parts by weight, based on 100 parts by weight of the system resin.

The resin composition of the present invention further contains, as a component (c), an isocyanurate compound having an epoxy group. As the isocyanurate compound having an epoxy group, a compound having three epoxy groups is preferable, and tris (2,3-epoxypropyl) isocyanurate is particularly preferable. The amount of the component (c) is preferably 0.5 to 10.0 parts by weight, more preferably 1 to 8 parts by weight, based on 100 parts by weight of the total of the components (a) and (b). I do. If the amount is less than 0.5 part by weight, the effect on hydrolysis resistance tends to be small, and if it exceeds 10 parts by weight, the solderability tends to be extremely reduced.

Commercially available products of tris (2,3-epoxypropyl) isocyanurate include TEPIC (Nissan Chemical Co., Ltd.).

The resin composition for electrical insulation of the present invention may contain, if necessary, an organic metal compound, for example, a metal salt such as a zinc salt, a lead salt, a manganese salt, or a tin salt of an aliphatic carboxylic acid such as naphthenic acid. And the like can be added, and these improve the linear speed at the time of baking insulated wires, shorten the curing time, lower the curing temperature, and improve the solderability. The preferable addition amount is 0.02 to 0.1% by weight in terms of metal based on the resin.

Further, the resin composition for electrical insulation of the present invention comprises:
It can be dissolved in a solvent and adjusted to an appropriate viscosity before use. At this time, as a solvent to be used, for example, phenol, cresol, xylenol, cellosolves, cartols, xylene and the like are used.

The resin composition for electrical insulation of the present invention is applied onto a conductor such as a copper wire by a known method directly or via another insulating material, and baked to obtain solderability, heat resistance and environmental resistance. An insulated wire excellent in quality can be obtained.

[0028]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited by these examples.

Example 1 In a four-necked flask equipped with a thermometer, a stirrer and a condenser, 99 g of 4,4'-diaminodiphenylmethane (0.
5 equivalents), 192 g of trimellitic anhydride (1.0 equivalent), 291 g of dimethyl terephthalate (3.0 equivalents),
93 g (3.0 equivalents) of ethylene glycol, 92 g (3.0 equivalents) of glycerin, 217 g of cresol, and 3.8 g of tetrabutyl titanate were placed in a nitrogen stream, and 170 g of ethylene glycol was added.
The temperature was raised to ° C. and the reaction was carried out for 60 minutes. Next, the obtained solution was heated to 210 ° C. and reacted for 3 hours. Further, 436 g of cresol was added to this solution to obtain a polyester resin solution having an imide bond in a molecule having a nonvolatile content of 50% by weight.

A stabilized isocyanate compound (Coronate 2 (trade name, manufactured by Nippon Urethane Industry Co., Ltd.)) was added to 100 g of the obtained polyester resin solution having an imide bond in the molecule.
503) 125 g, Tris (2,3-epoxypropyl) isocyanurate (manufactured by Nissan Chemical Industries, Ltd., trade name TE)
PIC) 5.3 g (3.0% by weight), cresol 210
g, 55 g of xylene and 1.5 g of zinc naphthenate were added to obtain a resin composition of the present invention.

Example 2 A 100 g of a polyester resin solution having an imide bond in the molecule obtained in Example 1 was added to a stabilized isocyanate compound (Coronate 2 (trade name, manufactured by Nippon Urethane Industry Co., Ltd.)).
503) 125 g, Tris (2,3-epoxypropyl) isocyanurate (manufactured by Nissan Chemical Industries, Ltd., trade name TE)
PIC) 8.8 g (5.0% by weight), cresol 210
g, 55 g of xylene and 1.5 g of zinc naphthenate were added to obtain a resin composition of the present invention.

Comparative Example 1 100 g of a polyester resin solution having an imide bond in the molecule obtained in Example 1 was mixed with a stabilized isocyanate compound (Coronate 2 (trade name, manufactured by Nippon Urethane Industry Co., Ltd.)).
503) 125 g, cresol 210 g, xylene 55
g and 1.5 g of zinc naphthenate were added to obtain a resin composition.

Test Example The resin compositions obtained in the above Examples and Comparative Examples were applied to a copper wire having a diameter of 0.4 mm according to the following baking conditions.
Baking was performed at a linear speed of 60 m / min to produce insulated wires. [Baking conditions] Baking furnace; hot air circulating horizontal furnace (furnace length: 3.3 m) Furnace temperature; inlet / outlet = 400 ° C / 400 ° C The general characteristics of the obtained wire enameled wire are JIS-C3.
The measurement was performed according to 5 to 19 of 003, and the results are shown in Table 1. As for the hydrolysis resistance, JIS-C300
The twisted electric wire prepared according to 3 was put into a pressure-resistant tube with a volume of 200 ml and a water content of 0.2% (based on the volume), heated to 120 ° C., and the dielectric breakdown voltage with time was measured. Are shown in Table 2.

[0034]

[Table 1]

[0035]

[Table 2] From the results shown in Tables 1 and 2, the insulated wires manufactured using the resin compositions obtained in Examples 1 and 2 were compared with Comparative Example 1
Compared to those prepared using the resin composition obtained in
It can be seen that it has remarkably high hydrolysis resistance and has other properties similar to those obtained in Comparative Example 1.

[0036]

Industrial Applicability The resin composition of the present invention has good solderability, excellent heat resistance, and remarkably improved environmental resistance, especially hydrolysis resistance, as compared with conventional polyurethane wires. It is possible to provide an insulated wire with improved reliability.

Claims (4)

[Claims] 1. An electric insulating resin composition comprising (a) a polyester resin having an imide bond in a molecule, (b) a stabilized isocyanate, and (c) an isocyanurate compound having an epoxy group. 2. An isocyanurate compound having an epoxy group as the component (c) in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of the total of the polyester resin as the component (a) and the stabilized isocyanate as the component (b). Claim 1
The resin composition for electrical insulation according to the above. 3. The resin composition according to claim 1, wherein the isocyanurate compound having an epoxy group as the component (c) is tris (2,3-epoxypropyl) isocyanurate. 4. An insulated wire obtained by applying the resin composition for electrical insulation according to claim 1, 2 or 3 onto a conductor directly or via another insulating material and baking it.