JPH07100768B2 - Polyester insulation paint - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polyester insulating coating, and more particularly to a novel polyester insulating coating capable of economically providing an insulated wire excellent in solder releasability. Is.

(Prior Art and Problems Thereof) In recent years, there have been remarkable reductions in size and weight of electric devices such as motors and transformers. This contributes to miniaturization and weight reduction of not only home electric appliances but also automobiles and aircrafts. Furthermore, it is strongly desired to improve the reliability of electric devices.

From these viewpoints, a material with excellent heat resistance is required as a coating material for insulated electric wires used in electric devices such as motors and transformers, and polyester insulated electric wires using an insulating coating mainly composed of polyester resin are required. B type (130
(° C) to F type (155 ° C) insulated electric wires.

Also, in order to reduce the size and weight of the equipment, it is necessary to make the wire thinner, and the thin polyester insulated wire is loaded with more load than before. Naturally, a higher performance polyester insulated wire is required. It came to be requested.

Further, since these polyester insulated wires are used in a harsh environment, it goes without saying that in addition to heat resistance, chemical resistance, solvent resistance, hydrolysis resistance and alkali resistance are required. .

On the other hand, electrical equipment manufacturers are seeking rationalization of processes for cost reduction and demanding higher performance than conventional insulating paints.

As part of this, there are labor-saving and line-up processes for terminal stripping of insulated wires.

Currently, this terminal stripping treatment method includes (1) mechanical stripping,
Although there are various methods such as (2) thermal decomposition peeling, (3) chemical peeling, (4) solder peeling, etc., the solder of (4) above is taken into consideration in consideration of working time, flawless conductor of thin wires and continuous treatment. The peeling treatment method is most preferable.

However, although a polyester insulated electric wire made of a conventional polyester insulating coating has already been made into a line by peeling a chemical, it requires a certain period of time for immersion in the chemical and must be washed. In addition, since it is dangerous in terms of handling, attempts have been made to form a line by peeling solder, but none of the conventional polyester insulated wires has a solder peeling property.

Insulated wires that can be subjected to solder peeling treatment include polyurethane insulated wires containing polyurethane resin as the main component and polyester imide insulated wires containing polyester imide resin as the main component. It has low E type (120 ° C) and the latter is F type (155
However, it is expensive because it contains a large amount of imide groups, and is used only in a specific field.

For this reason, an electric equipment manufacturer strongly desires an insulating paint capable of performing a solder peeling treatment, so-called solder peeling, and providing an insulated wire having a heat resistance of B type (130 ° C) to F type (155 ° C). There is.

In this field, the expression "possible for solder peeling treatment" means that when the insulated wire is immersed in a heated solder bath, the insulating coating is decomposed and removed at the immersed portion, and at this point the conductor is soldered. It means that soldering is easy because it is marked with, and it does not mean that soldering can be done directly.

In addition, recently, when soldering a large number of twisted insulated wires, it is possible to remove the insulating coating and solder it all at once by directly immersing the insulated wire covered with the insulating coating in a solder bath. It has increased. For this purpose, the insulating coating must be removed as quickly or instantaneously as possible following immersion in the solder bath. It goes without saying that the shorter the immersion in the solder bath, the better.
In the solder stripping, when the temperature of the molten solder bath exceeds 450 ° C, the oxidative deterioration of the solder bath progresses further, and the speed at which the copper, which is the conductor, dissolves in the solder becomes faster, causing the problem of thinning of the insulated wire. Come on.

As a result of earnest research to meet the above-mentioned demand, the present inventor has found that an insulating coating material satisfying the above-mentioned demand can be obtained by using a specific polyester resin.

(Means for Solving Problems) That is, the present invention provides (A) a divalent carboxylic acid or a derivative thereof or 10 to 50 equivalent% of a mixture thereof and (B) a trivalent carboxylic acid or a derivative thereof or a mixture thereof. A polyester resin obtained by reacting 3 to 30 equivalent% of a mixture, (C) 20 to 50 equivalent% of a dihydric alcohol, and (D) 5 to 40 equivalent% of a trivalent aliphatic alcohol in the resin The polyester insulating coating composition is characterized in that the carboxyl group is dissolved in an organic solvent without being neutralized by a base.

(Function) The insulating coating material of the present invention, by using a specific polyester resin, provides an insulated electric wire having excellent thermal, mechanical, electrical and chemical properties, and also having good solder peeling property. You can

(Preferred Embodiment) Next, the present invention will be described in more detail with reference to the preferred embodiments of the present invention.

The polyester resin, which is the main component of the polyester insulating coating material of the present invention, has the above-mentioned components (A) and (B) as acid components.
It is obtained by using a component, the above-mentioned component (C) and component (D) as an alcohol component, and esterifying them according to a conventional method. Generally, the above raw materials are almost used as they are, but their precursors can also be used.

(A) as a constituent factor of the polyester resin,
In (B), (C) and (D), (A) is 10 to 50 equivalent%, (B) is 3 to 30 equivalent%, (C) is 20 to 50 equivalent% and (D) is 5 to 40%. It is preferable that the main component is the one obtained by reacting in the equivalent%.

When (A) is less than 10 equivalent% in the above usage amount,
The insulated wire obtained by the insulating coating material of the present invention has insufficient flexibility, while when it exceeds 50 equivalent%, heat resistance becomes insufficient, which is not preferable. If (B) is less than 3 equivalent%, the resulting insulated wire has insufficient solder releasability. On the other hand, if it is more than 30 equivalent%, it is difficult to synthesize the resin and the coating film is formed. This is not preferable because it reduces the flexibility. Further, if (C) is less than 20 equivalent%, the flexibility of the coating of the obtained insulated electric wire is significantly reduced, while
If it exceeds 50 equivalent%, the heat resistance will decrease. or,
When (D) is less than 5 equivalent%, the softening temperature of the coating of the obtained insulated wire is lowered, while when it exceeds 40 equivalent%, the solder peeling property is deteriorated, which is not preferable.

Therefore, in order to balance the solder releasability and other characteristics of the insulated wire with the polyester insulating coating of the present invention in a well-balanced manner, it is most preferable that (A) and (B) are 30 to 30 in total.
It is preferable to use a resin obtained by reacting at 50 equivalent% and the total of (C) and (D) is 40 to 100 equivalent%. This reaction ratio is OH / COOH> 1, and a resin having a large number of hydroxyl groups at the ends is obtained, and the hydroxyl groups are subsequently reacted with a crosslinking agent such as polyisocyanate to form a crosslinked film on the surface of the electric wire.

Examples of the divalent carboxylic acid or its derivative or the mixture (A) thereof used in the present invention include isophthalic acid, terephthalic acid, 1,2-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, and 1,5-naphthalene. Dicarboxylic acid, 1,6-naphthalene dicarboxylic acid, 1,7-naphthalene dicarboxylic acid, 1,8-naphthalene dicarboxylic acid, diphenyl-2,2'-dicarboxylic acid, diphenyl-2,3'-dicarboxylic acid, diphenyl-2 , 4'-dicarboxylic acid, diphenyl-3,3'-dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, diphenylmethane-2,2'-dicarboxylic acid, diphenylmethane-4,4'-dicarboxylic acid , Diphenylethane-4,4'-dicarboxylic acid, diphenylsulfone-4,
4'-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, benzophenone-4,4'-dicarboxylic acid, phthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, adipic acid, succinic acid, maleic acid, Sebacic acid, isosebacic acid, dimer acid, tetrachlorophthalic acid, 4,4'-dicarboxy-diphenylmethane, 4,4'-dicarboxy-diphenylpropane and the like can be mentioned.

Next, as the derivative of the above acid, there is firstly an ester, and examples thereof include a lower dialkyl ester of the above carboxylic acid, for example, in the case of terephthalic acid, dimethyl terephthalate,
Diethyl terephthalate, dipropyl terephthalate,
Examples thereof include dibutyl terephthalate, diamyl terephthalate, dihexyl terephthalate, dioctyl terephthalate or half esters thereof, such as monomethyl terephthalate.

Other derivatives include carboxylic acid dihalides of the above-mentioned carboxylic acids, for example, carboxylic acid dichlorides, and further acid anhydrides of the above-mentioned carboxylic acids, such as phthalic anhydride.

Further, it is possible to use not only the above carboxylic acid and its derivative but also a mixture thereof.

Particularly preferred as (A) is a case where isophthalic acid, terephthalic acid or a derivative thereof, or a part of these is replaced with another carboxylic acid or a derivative thereof.

Examples of the trivalent carboxylic acid or its derivative (B) include:
For example, in addition to trimellitic acid and trimemic acid, further, trimellitic acid anhydride, hemimellitic acid anhydride, 1,2,5-naphthalene tricarboxylic acid anhydride, 2,3,6-naphthalene tricarboxylic acid anhydride, 1,8,4-naphthalene tricarboxylic acid anhydride, 3,4,4'-diphenyl tricarboxylic acid anhydride, 3,4,4'-diphenyl methane tricarboxylic acid anhydride, 3,4,4'-diphenyl acid Examples thereof include ether tricarboxylic acid anhydride and 3,4,4'-benzophenone tricarboxylic acid anhydride.

Derivatives of these trivalent carboxylic acids include their esters, but particularly useful ones are trimellitic anhydride and trimellitic acid.

Examples of the dihydric alcohol (C) include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, dipropylene glycol, 1,3-propanediol, various butanes, pentanes, and Or hexanediol,
For example, 1,3- or 1,4-butanediol 1,5-pentanediol 1,6-hexanediol, 1,4-butene-2-diol, 2,2-dimethylpropanediol-1,3, 2- Ethyl-2-butyl-propanediol-1,3,1,4-dimethylolcyclohexane, 1,4-butenediol, water-added bisphenols (for example, water-added P, P'-dihydroxydiphenylpropane or its homologues) ), Cyclic glycols such as 2,2,4,4-tetramethyl-1,3-cyclobutanediol, hydroquinone-di-β-hydroxyethyl-ether, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediethanol. , Trimethylene glycol, hexylene glycol, octylene glycol and the like.

Particularly preferred are ethylene glycol, 1,2-propylene glycol and 1,6-hexanediol.

The trihydric aliphatic alcohol referred to in the present invention refers to one that does not contain an aromatic or heterocyclic ring at any position in the molecule. When a trihydric alcohol or a tetrahydric or higher alcohol containing an aromatic group or a heterocyclic group is used, the releasability of the solder is significantly impaired, so that it is not preferable to add it.

Examples of these trihydric aliphatic alcohols (D) include:
Examples thereof include glycerin, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, and the like, and glycerin is particularly preferable.

In the present invention, the following method can be mentioned as an embodiment for synthesizing a polyester resin using these raw material compounds.

(1) 180 to 2 raw materials (A), (C) and (D)
After reacting at 30 ° C for 2 to 10 hours, (B) is added,
A method for synthesizing a polyester resin by further promoting an esterification reaction at 200 to 260 ° C.

(2) 180 to 2 of raw materials (B), (C) and (D)
After reacting at 30 ° C for 2 to 10 hours, (A) is added,
A method for synthesizing a polyester resin by further promoting an esterification reaction at 200 to 260 ° C.

(3) Raw materials (A), (B), (C) and (D)
Are mixed together and the esterification reaction is allowed to proceed at 180 to 260 ° C. for 3 to 15 hours to synthesize a polyester resin.

The polyester resin obtained by the reaction of raw materials (A), (B), (C) and (D) has OH / COOH> 1.
Since the reaction is carried out at a ratio of 1, the composition generally contains a large amount of hydroxyl groups, but also contains a small amount of carboxyl groups. In the present invention, the carboxyl group is not neutralized with a base but dissolved or adjusted to an appropriate concentration with a solvent to obtain the insulating coating material of the present invention.

Examples of the solvent include solvents having a phenolic hydroxyl group, such as phenol, o-cresol, m-cresol,
p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, on-propylphenol, 2,4 , 6-trimethylphenol, 2,3,5-trimethylphenol, 2,4,5-trimethylphenol, 4
It is preferred to use cresylic acid, which is -ethyl-2-methylphenol, 5-ethyl-2-methylphenol and mixtures thereof. In addition, polar solvents such as N-methyl-2-pyrrolidone and N, N-dimethylacetamide can be used.

As the diluting solvent, for example, aliphatic hydrocarbons, aromatic hydrocarbons, ethers, acetals, ketones, esters and the like can be used.

Examples of the aliphatic hydrocarbon and the aromatic hydrocarbon include, for example,
n-heptane, n-octane, cyclohexane, decalin, dipentene, pinene, p-menthane, decane, dodecane, tetradecane, benzene, triene, xylene,
Examples include ethylbenzene, diethylbenzene, isopropylbenzene, amylbenzene, p-cymene, tetralin, or a mixture thereof, petroleum naphtha, coal tar naphtha, and solvent naphtha.

The most useful solvent for the polyester resin insulation coating of the present invention is cresylic acid. Cresolic acid has a boiling range of 180-230 ° C, which contains phenol, o-cresol, m-cresol, p-cresol, xylenols.

A part of this cresylic acid is diluted with an aromatic hydrocarbon, for example, petroleum naphtha, coal tar naphtha, solvent naphtha, etc., to improve workability in manufacturing an insulated wire by coating and baking an insulating paint on a conductor. Can be improved.

Examples of these diluting solvents include xylene, Solvent Naphtha No. 2, Solvesso # 100 and Solvesso # 150.
Etc., and these are used in an amount of 0-30% of the weight of the solvent.
However, it is preferably 10 to 20%.

When the insulating coating of the present invention thus obtained is applied to a conductor and baked to produce an insulated wire, the use of a small amount of a metal desiccant improves the surface smoothness of the insulated wire and improves the take-up speed. It is preferable because it can be speeded up and the workability is further improved.

As these metal desiccants, zinc, calcium or lead octoate, linoleate, etc. are useful, for example, zinc octoate, calcium naphthenate, zinc naphthenate, lead naphthenate, lead linonate, calcium linoleate, zinc resinate, etc., Other examples include manganese naphthenate and cobalt naphthenate.

However, a further advantage is to use compounds of titanic acid and zirconic acid instead of these metal desiccants.

Examples of typical titanic acid compounds include tetraalkyl titanates such as tetraisopropyl titanate, tetrabutyl titanate, tetrahexyl titanate, tetramethyl titanate, tetrapropyl titanate, and tetraoctyl titanate.

Also useful are tetraalkyltitanium chelates obtained by reacting tetraalkyltitanate with octyleneglycol, triethanolamine, 2,4-pentadiene, acetoacetic acid ester and the like.

Further, tetraalkyl titanium acylate obtained by reacting tetraalkyl titanate with stearic acid and the like is also useful.

Examples of the zirconic acid compound include tetraalkyl zirconates, zirconium chelates, and zirconium acylates corresponding to the above titanic acid compounds.

The addition amount of these metal compounds is 0.1 to 8.0% by weight, preferably 1 to 3% by weight, based on the solid content of the insulating coating.

Further, a stabilized polyisocyanate obtained by blocking the isocyanate group of polyisocyanate with phenol, cresol or the like can be used as a curing agent. Examples of these include cyclic trimers of 2,4-tolylene diisocyanate, cyclic trimers of 2,6-tolylene diisocyanate, dimers of diphenylmethane-4,4'-diisocyanate, 3 moles of Reaction product of diphenylmethane-4,4'-diisocyanate with 1 mol of trimethylolpropane, reaction product of 3 mol of 2,4-tolylene diisocyanate with 1 mol of trimethylolpropane, 3 mol of 2 , 6-
Reaction product of tolylene diisocyanate with 1 mol of trimethylol propane, 3 mol of reaction product of 2,4-tolylene diisocyanate with 1 mol of trimethylol ethane, 3 mol of 2,6-tolylene diisocyanate Reaction product with 1 mol of trimethylolethane, reaction product of mixed 3 mol of 2,4- and 2,6-tolylene diisocyanate with 1 mol of trimethylolpropane, mixed 2,4- and 2 Examples thereof include stabilized polyisocyanates obtained by blocking a cyclic trimer of 6,6-tolylene diisocyanate with phenol or cresol. Further, stabilized isocyanates obtained by blocking diphenylmethane-4,4'-diisocyanate with xylenol are also useful.

In addition, by adding 0.1 to 5% by weight of phenol-formaldehyde resin, melamine-formaldehyde resin, cresol-formaldehyde resin, xylene-formaldehyde resin, epoxy resin and silicone resin, the appearance workability of the insulated wire can be further improved. . If these resins are less than 0.1% by weight, there is no effect in improving workability. If it is added in an amount of 5% by weight or more, carbides are remarkably formed during solder peeling, which is not preferable. Particularly preferred resins are phenol-formaldehyde resin and xylene-formaldehyde resin, and by adding 1 to 2% by weight of these resins, the appearance workability can be improved without impairing the solder peeling property of the insulated wire.

The above is the content of the polyester insulating coating material of the present invention, and an insulated wire made of the insulating coating material is provided by applying the polyester insulating coating material of the present invention on a conductor and baking it to a predetermined coating thickness.

The conductor used at this time is, for example, copper, silver or stainless steel wire, and the applicable conductor diameter may be any diameter from an ultrafine wire to a thick wire, and is limited to a specific conductor diameter. Not a thing. Generally, the diameter is about 0.050 to 2.0 mm
Mainly applied to copper wire of degree.

The method of forming an insulating coating on the conductor may be based on a conventionally known method, for example, by applying an insulating coating by a method such as a felt drawing method or a die drawing method, and continuously applying a temperature of about 350 to 550 ° C. The desired insulating film is formed by passing it through the baking furnace several times or a dozen times. The thickness of the insulating film is the film thickness specified in the standards such as JIS, NEMA or IEC.

(Effect) According to the present invention as described above, a polyester-insulated electric wire that can be soldered is economically provided.

Next, the contents of the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the text,% is based on weight unless otherwise specified.

Example 1 equipped with a stirrer, nitrogen gas introduction tube, thermometer and cooling tube 3,
To a 000cc four-necked flask, terephthalic acid 581g (7.0 equivalents) ethylene glycol 279g (9.0 equivalents) glycerin 186g (6.0 equivalents) tetrabutyl titanate 2g was added and mixed and stirred to 200
The temperature is raised to 8 ° C over 8 hours, 192 g (3.0 equivalents) of trimellitic anhydride is further added to this system, and the esterification reaction is allowed to proceed at 220 ° C for 3 hours. The degree of reaction was measured by the increase in viscosity, and samples were taken over time.

The end point of the reaction is Z _{3 in} cresol when the viscosity of the resin sample is 40%.
When it became (Gardner viscometer), cresol 1614g
To a nonvolatile content of 40%, and to this, Nisseki Chemical Hisol #
Add 100 to make a resin solution with a nonvolatile content of 35%.

Further, 3% of tetrabutyl titanate was added to the resin component to obtain the insulating coating material of the present invention.

Example 2 Dimethyl terephthalate 679 g (7.0 eq) Trimellitic anhydride 192 g (3.0 eq) Ethylene glycol 279 g (9.0 eq) Glycerin 186 g (6.0 eq) Lisage 0.7 g Except for using the above ingredients, Others were the same as in Example 1 to obtain an insulating coating material of the present invention.

Example 3 Dimethyl terephthalate 679 g (7.0 eq) Trimellitic anhydride 192 g (3.0 eq) Propylene glycol 342 g (9.0 eq) Glycerin 186 g (6.0 eq) Lisage 0.7 g Except that the above ingredients were used, Others were the same as in Example 1 to obtain an insulating coating material of the present invention.

Example 4 Dimethyl terephthalate 679 g (7.0 equivalents) Trimellitic anhydride 192 g (3.0 equivalents) 1,6-hexanediol 531 g (9.0 equivalents) Glycerin 186 g (6.0 equivalents) Lisage 0.7 g Using the above components Except for the above, the insulating coating material of the present invention was obtained in the same manner as in Example 1.

Example 5 Dimethyl terephthalate 388 g (4.0 equivalents) Isophthalic acid 249 g (3.0 equivalents) Trimellitic anhydride 192 g (3.0 equivalents) Ethylene glycol 279 g (9.0 equivalents) Glycerin 184 g (6.0 equivalents) Lisage 0.6 g The above components An insulating coating material of the present invention was obtained in the same manner as in Example 1 except that was used.

Example 6 Dimethyl terephthalate 388 g (4.0 equivalents) Phthalic anhydride 222 g (3.0 equivalents) Trimellitic anhydride 192 g (3.0 equivalents) Ethylene glycol 279 g (9.0 equivalents) Glycerin 186 g (6.0 equivalents) Resurge 0.4 g Above An insulating coating material of the present invention was obtained in the same manner as in Example 1 except that the components were used.

Example 7 Dimethyl terephthalate 679 g (7.0 equivalents) Trimellitic anhydride 192 g (3.0 equivalents) Ethylene glycol 140 g (4.5 equivalents) Propylene glycol 171 g (4.5 equivalents) Glycerin 186 g (6.0 equivalents) Lisage 0.7 g The above components An insulating coating material of the present invention was obtained in the same manner as in Example 1 except that was used.

Example 8 Dimethyl terephthalate 679 g (7.0 equivalents) Trimellitic anhydride 192 g (3.0 equivalents) Ethylene glycol 140 g (4.5 equivalents) 1,6-hexanediol 171 g (4.5 equivalents) Glycerin 184 g (6.0 equivalents) Lissajous 0.7 g An insulating coating material of the present invention was obtained in the same manner as in Example 1 except that the above components were used.

Example 9 Dimethyl terephthalate 679 g (7.0 equivalents) Trimellitic anhydride 192 g (3.0 equivalents) Ethylene glycol 279 g (9.0 equivalents) Trimethylolpropane 270 g (6.0 equivalents) Lisage 0.7 g Except that the above components were used In the same manner as in Example 1 except for the above, the insulating coating material of the present invention was obtained.

Example 10 Dimethyl terephthalate 582 g (6.0 eq) Trimellitic anhydride 256 g (4.0 eq) Ethylene glycol 419 g (13.5 eq) Glycerin 47 g (1.5 eq) Resurge 0.6 g Except for using the above ingredients, Others were the same as in Example 1 to obtain an insulating coating material of the present invention.

Example 11 Dimethyl terephthalate 388 g (4.0 eq) Trimellitic anhydride 384 g (6.0 eq) Ethylene glycol 419 g (13.5 eq) Glycerin 47 g (1.5 eq) Lisage 0.4 g Except for using the above ingredients, Others were the same as in Example 1 to obtain an insulating coating material of the present invention.

Comparative Example 1 To the same apparatus as in Example 1, was added dimethyl terephthalate 776 g (8.0 equivalents) isophthalic acid 166 g (2.0 equivalents) ethylene glycol 251 g (8.0 equivalents) glycerin 171 g (5.5 equivalents) litharge 0.8 g, After mixing and stirring, the temperature is raised to 200 ° C. over 8 hours, and the condensation reaction is further advanced at 220 to 240 ° C. for 3 hours. The degree of reaction was measured by the increase in viscosity, and samples were taken over time.

The reaction end point in the viscosity of the resin sample is 40% cresol in Z ₂ -
Cresol 1602 when Z ₃ (Gardner viscometer)
Add g to make the nonvolatile content 40%, and add Nisseki Chemical Hysol # 100 to this to make a resin solution having a nonvolatile content of 35%.

Further, 3% of tetrabutyl titanate and zinc octenoate (zinc content 8%) were added to the resin content as Zn to make 0.3% to obtain an insulating coating composition of a comparative example.

Comparative Example 2 dimethyl terephthalate 970 g (10.0 equivalents) ethylene glycol 186 g (6.0 equivalents) glycerin 279 g (9.0 equivalents) litharge 1.0 g Comparative Example 1 except that the above components were used. Got insulation paint.

In performing the performance test of these insulating paints, the insulating paints of the present invention and comparative examples were applied and baked under the following conditions to produce insulated wires.

Conductor diameter: 1.00 m / m Baking furnace; Vertical baking furnace with an effective furnace length of 2.5 m Baking temperature: 500 ° C (maximum temperature) Drawing method: Die method Coating frequency: 6 times Coating thickness: 0.035 to 0.040 m / m test Method is JIS C 3003-1
The test was performed according to the test method for enamel copper wire and enamel aluminum wire of 984. The test results are shown in Table 1.

As is apparent from the above test results, when the polyester insulating coating according to the present invention is used, it has the same or better characteristics in general characteristics as compared with those using the conventional polyester insulating coating, and it is excellent. It is clear that it has solder releasability.

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Claims (1)

[Claims] 1. (A) 10 to 50 equivalent% of a divalent carboxylic acid or derivative thereof or a mixture thereof and (B) 3 to 30 equivalent% of a trivalent carboxylic acid or a derivative thereof or a mixture thereof.
And (C) dihydric alcohol 20 to 50 equivalent% and (D) trihydric aliphatic alcohol 5 to 40 equivalent% by reacting the resulting polyester resin with a carboxyl group in the resin by a base. A polyester insulating paint characterized by being dissolved in an organic solvent without being neutralized.