JP2000095939A - Electrical insulation resin composition and insulated wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition which yields an insulated wire having a solderability, a greater heat resistance compared to conventional polyurethane wires and a high resistance to environment, especially resistance to hydrolysis, and an insulated wire using this. SOLUTION: An electrical insulation resin composition contains a monocarbodiimide compound of formula I (R1 and R2 are each independently an organic group). An insulated wire is prepared by applying this electrical insulating resin composition directly on a conductor or via other insulants and baking it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-insulating erasing composition 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]

According to the present invention, there are provided (a) a polyester resin having an imide bond in a molecule, (b) a stabilized isocyanate, and (c) a total amount of 100% by weight of the polyester resin and the stabilized isocyanate. 0.5 to 10 parts by weight of the general formula (I)

Embedded image [Wherein R ¹ and R ² each independently represent an organic group] and a resin composition for electrical insulation containing a monocarbodiimide compound represented by the formula: Coating and baking.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The resin composition of the present invention contains the components (a) to (c) as described above. (A)
The polyester resin having an imide bond in the molecule used as a component is obtained by a reaction between an acid component and an alcohol component. In order to introduce an imide bond into the resin, a polyester represented by the general formula ( II)

Embedded image [In the formula, R 'represents a divalent organic group] It is preferable to use an imidodicarboxylic acid represented by the formula: General formula (I
In I), R ′ represents, for example, a residue of a diamine compound capable of forming an imide bond by reacting with an acid anhydride.

The imidodicarboxylic acid represented by the general formula (II) is prepared 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, diaminodiphenylsulfone, and the like. Is mentioned. In the present invention, a diisocyanate corresponding to the above-mentioned diamine may be used in place of these diamines.

The amount of the imidodicarboxylic acid represented by the general formula (II) is in the range of 10 to 30% by weight of the total acid component in view of the solderability, heat resistance and thermal shock resistance of the final composition. preferable. The acid component other than the imidodicarboxylic acid used in the polyester resin having an imide bond in the molecule includes terephthalic acid or a lower alkyl ester thereof, for example, dimethyl terephthalate, monomethyl terephthalate, diethyl terephthalate, and the like. 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. In addition, from the viewpoint of solderability and heat resistance, it is preferable to set the equivalent ratio of all alcohol components / all acid components to 1.3 to 2.5,
It is more preferable to be 1.6 to 2.4.

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 imidodicarboxylic acid may be a previously synthesized one, or a mixture of an imide acid component such as diamine, trimellitic anhydride and the like at the same time as the other acid component and the alcohol component, followed by imidization and esterification. May be performed simultaneously. In addition, the synthesis of a polyester resin having an imide bond in the molecule is preferably performed in the coexistence of a phenol solvent such as phenol, cresol, and xylenol, because the viscosity at the time of synthesis is high.

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, 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 a phenol (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 may further comprise, as a component (c), a compound represented by the general formula (I):

Embedded image [Wherein R ¹ and R ² each independently represent an organic group]. Examples of the organic group represented by R ¹ and R ² include an aromatic group such as a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, for example, a phenyl group, a toluyl group, and a 2,6-diisopropylphenyl. There are groups. Examples of the monocarbodiimide compound include N, N'-di-o-toluylcarbodiimide, N, N'-diphenylcarbodiimide,
N'-di-2,6-dimethylphenylcarbodiimide,
N, N'-bis (2,6-diisopropylphenyl)-
Carbodiimide and the like. Among these, N, N'-bis (2,6-diisopropylphenyl)-
Carbodiimide is preferable because of its low thermal decomposition property at the time of baking the electrically insulating paint.

The monocarbodiimide compound represented by the general formula (I) is obtained by subjecting the corresponding isocyanate compound to heat condensation in the presence of sodium methylate or sodium phenolate as a catalyst, followed by distillation. Can be. For example, N, N'-bis (2,6-diisopropylphenyl) -carbodiimide is prepared by using 2,6-diisopropylphenyl isocyanate as a catalyst in the presence of sodium methylate for about 20 minutes.
After condensation at 0 ° C., it is obtained by distillation.

In the present invention, the addition amount of the carbodiimide compound represented by the general formula (I) is 0.5 to 1 with respect to 100 parts by weight of the total amount of the components (a) and (b).
0 parts by weight, preferably 1 to 8 parts by weight. If the amount is less than 0.5 part by weight, the effect on hydrolyzability is small, and if it exceeds 10 parts by weight, the appearance and other general properties of the obtained enameled wire are adversely affected. The method of adding the carbodiimide compound is not particularly limited, but is preferably added after the final step of synthesis or after coating, and the carbodiimide compound is added as it is or dissolved in a suitable organic solvent such as cresol or xylene. .

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 is added to the resin composition for electrical insulation of the present invention. These can improve the wire speed at the time of baking insulated wires, shorten the curing time, lower the curing temperature, and improve the solderability. Further, 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 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 or the like directly or through another insulating material by a known method and baked to obtain solderability, heat resistance and environmental resistance. An insulated wire excellent in quality can be obtained.

[0019]

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 a nonvolatile content of 50% by weight and having an imide bond in the molecule. 100 g of a polyester resin solution having an imide bond in the molecule obtained is stabilized with an isocyanate compound (Coronate 25 manufactured by Nippon Urethane Industry Co., Ltd.)
03) 125 g, N, N'-di-o-toluylcarbodiimide 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 stabilized isocyanate compound (Coronate 25, trade name, manufactured by Nippon Urethane Industry Co., Ltd.) was added to 100 g of the polyester resin solution having an imide bond in the molecule obtained in Example 1.
03) 125 g, N, N'-di-o-tolylcarbodiimide 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 A stabilized isocyanate compound (Coronate 25, trade name, manufactured by Nippon Urethane Industry Co., Ltd.) was added to 100 g of the polyester resin solution having an imide bond in the molecule obtained in Example 1.
03) 125 g, cresol 210 g, xylene 55 g
And 1.5 g of zinc naphthenate were added to obtain a resin composition of the present invention.

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, and baked at a wire speed of 60 m / min. Each was produced. 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 stranded electric wire prepared according to 3 is put into a pressure-resistant tube having a volume of 200 ml and a water content of 0.2% (based on the volume),
After heating to 120 ° C., the dielectric breakdown voltage over time was measured, and the results are shown in Table 2.

[0024]

[Table 1]

[0025]

[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 manufactured using the resin composition obtained in Comparative Example 1. It can be seen that it has remarkably high hydrolysis resistance as compared with that of Comparative Example 1, and also has other properties similar to those obtained in Comparative Example 1.

[0027]

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 (2)

[Claims] 1. A polyester resin having an imide bond in a molecule (a), a stabilized isocyanate (b) and (c) a polyester resin and a stabilized isocyanate in an amount of 0.5 to 100 parts by weight in total. 10 parts by weight of the general formula (I) [Wherein R ¹ and R ² each independently represent an organic group]. A resin composition for electrical insulation containing a monocarbodiimide compound represented by the formula: 2. An insulated wire obtained by applying the resin composition for electrical insulation according to claim 1 onto a conductor directly or via another insulating material and baking it.