JPH01225627A - Polyesterimide resin - Google Patents

Abstract

PURPOSE:To produce a polyesterimide resin which gives an insulated electric wire excellent in solder release characteristics and workability, by reacting a specific dibasic carboxylic acid with a trihydric alcohol, a dihydric alcohol and a trihydric aliphatic alcohol. CONSTITUTION:The aimed resin is produced by reacting a specific dibasic carboxylic acid (A) which does not contain a 5-membered ring imide group or a mixture (A) of such acids, a dibasic carboxylic acid (B) which contains a 5-membered ring imide group or a derivative (B) thereof or a mixture (B) of such acids or derivatives, a trihydric alcohol (C) which is a reaction product of trimellitic acid or trimellitic anhydride and a dihydric alcohol, a dihydric alcohol (D), and a trihydric aliphatic alcohol (B) in the presence of an organic solvent. In prior art, solder release characteristics and heat resistance have been through to be properties quite incompatible to each other, but the present polyester resin makes it possible to give an insulated electrical wire wherein the softening temperature is 300 deg.C or above and at the same time the solder releasing treatment can be performed at 450 deg.C or below for 10sec or less.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to polyesterimide resin, and more specifically, to a novel polyesterimide resin that can provide an insulated wire with excellent solder removability, softening temperature, heat resistance, and workability. The invention relates to polyesterimide resin.

(Prior Art and its Problems) In recent years, electrical equipment such as motors and transformers have become significantly smaller and lighter. This plays a role in reducing the size and weight of not only home appliances but also automobiles and aircraft. Furthermore, there is a strong desire to improve the reliability of electrical equipment.

From these viewpoints, materials with excellent heat resistance are required as coating materials for insulated wires used in electrical equipment such as motors and transformers.

In addition, to make equipment smaller and lighter, it is necessary to make the wires thinner, and because the thinner insulated wires are subject to a higher load than before, naturally the insulated wires are required to have higher performance. It became like that.

As a result, the insulation paints applied to insulated wires have become more heat resistant, with thermally stable materials such as glycerin-containing polyesterimide resin of class F (155 °C) and tris-(2- and droxyethyl) isocyanurate (
Hereinafter abbreviated as 'n1EIG)-containing polyesterimide resin, H-type (180℃) THEI (:H-type (180℃))-containing polyesteramide-imide resin, H-type (180℃) THEIC-containing polyester resin, Ni-type (200℃) aromatic polyamide Imide resins and M class (220°C) polyimide resins have been developed.

Insulated wires coated with these resins as the main component are used in harsh environments, so in addition to heat resistance, they are required to have chemical resistance, solvent resistance, hydrolysis resistance, and alkali resistance. .

In addition, as the heat resistance of insulating paints improves, electrical equipment manufacturers are streamlining processes with the aim of reducing costs, and are also demanding higher performance than ever for insulating paints. As a link to this, there is labor-saving and line-based processing for stripping the ends of insulated wires.

However, since the insulated wires made of each of the resins described above have excellent chemical resistance, it is rather hindered from forming a line for stripping the ends of these insulated wires.

Currently, the processing methods for terminal peeling include (1) mechanical peeling;
There are various methods such as (2) pyrolysis peeling, (3) chemical peeling, and (4) solder peeling, but considering the working time, keeping the thin wire conductor intact, continuous processing, etc., the above method (4) is recommended. The peel treatment method is most preferred.

For this reason, electrical equipment manufacturers strongly desire a resin material that can be treated to remove solder, that is, can be used to remove solder, and that can provide insulated wires with heat resistance of class F (155°C) to class H (180°C). There is.

For this purpose, a polyesterimide resin that can be soldered off has been developed.

In this field, the expression "solder removal treatment is possible" means that when an insulated wire is immersed in heated solder,
The insulation film is decomposed and removed at the immersed portion, and at this point the conductor is left with solder, making it easier to solder, but does not mean that it can be soldered directly.

Recently, when soldering a large number of stranded insulated wires, it has become possible to remove the insulation film and solder the wires at the same time by immersing the wires with the insulation film still on them in a solder bath. It has increased. For this purpose, the insulating coating must be removed as quickly as possible, i.e. instantaneously, following immersion into the solder bath. It goes without saying that the shorter the immersion time in the solder bath, the better.

In solder stripping, the temperature of the molten solder bath is 400°C.
If this value is exceeded, the oxidation deterioration of the solder will further progress, and the rate at which copper, which is a conductor, will dissolve into the solder will increase, resulting in the problem of thinning of the insulated wire.

However, - although the conventional polyesterimide resin with solder removability described above has heat resistance of class F or higher, it completely decomposes the insulation film in the hunter bath and leaves a carbonized film on the conductor. In order to avoid this, it is necessary to set the temperature of the solder bath to 450°C or higher and to set the immersion time to 10 seconds or more, and the softening temperature is only 3 ha°C.

Therefore, even if the temperature of the solder bath is 450°C or less and the immersion time is 10 seconds or less, solder can be removed without leaving any carbonized film on the conductor, and the softening temperature of the upper layer can be removed. There is a need for a resin that provides an insulated wire with a

As a result of intensive research, the present inventors have discovered a specific polyesterimide resin that meets the above needs.

(Means for Solving the Problems) That is, the present invention provides (A) a divalent carboxylic acid or a derivative thereof that does not contain a five-membered ring imide group, or a mixture thereof, and (B) a five-membered ring imide group. (C) a trihydric alcohol which is a reaction product of trimellitic acid or trimellitic anhydride and a dihydric alcohol; and (D) a dihydric alcohol. and (E) a trivalent aliphatic alcohol in the presence of an organic solvent.

(Function) By using the polyesterimide resin of the present invention, an insulated wire having excellent thermal, mechanical, electrical, and chemical properties as well as good solder removability can be provided.

In other words, in the conventional technology, solder removability and heat resistance were considered to be completely contradictory properties, but in the present invention, 90%
A polyesterimide resin is provided that can provide an insulated wire that is compatible with a softening temperature of 0° C. or higher and a solder removal process of 450° C. or lower and 10 seconds or less.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments of the present invention.

The polyesterimide resin of the present invention uses the above-mentioned (A) component and (B) component as the acid component, and uses the above-mentioned (C) component, (D) component, and (E) component as the alcohol component, These are obtained by esterifying them according to a conventional method. - In most cases, the above raw materials are used as they are in the shell, but their precursors can also be used.

(A) as a constituent factor of the above polyesterimide resin
, (B), <C>, (D) and (E), (A) is 5
(B) is 5 to 30 equivalents, (C) is 10 to 25 equivalents, and (D) is O to 25 equivalents, (
Preferably, the main component is one obtained by reacting 25 to 40 equivalents of E).

In the above usage amount, when (A) is less than 5 equivalent %,
The flexibility of the coating of the insulated wire obtained with the resin of the present invention becomes insufficient, and the cost increases in terms of raw materials.

On the other hand, if the amount exceeds 35 equivalent %, the heat shock resistance of the insulated wire will be insufficient. On the other hand, if the amount exceeds 30 equivalent %, it will be difficult to synthesize the resin, which is not preferable. Also, (C) is 1
If it is less than 0 equivalent %, the solder removability of the obtained insulated wire will be reduced, while if it exceeds 25 equivalent %, the flexibility of the film of the obtained insulated wire will be insufficient. Also, (D
) exceeds 25 equivalent %, the heat resistance of the resulting insulated wire becomes low, and when (E) is less than 25 equivalent %,
The resulting insulated wire will have low heat resistance, and if it exceeds 40 equivalent %, flexibility and solder removability will deteriorate, which is not preferable.

Therefore, the solder releasability and softening temperature of the insulated wire made of the polyesterimide resin of the present invention, as well as the F to H types (155
-180°C), most preferably the total amount of (A) and (B) is 30 to 50 equivalent%, and the total amount of (C), (D) and (E) is 50% by weight.
It is preferable to use a resin obtained by reacting so that the amount is 70 to 70% by weight.

Examples of dicarboxylic acids, derivatives thereof, or mixtures thereof (A) used in the present invention include: isophthalic acid, terephthalic acid, 1.2-naphthalene dicarboxylic acid, 1.4-naphthalene dicarboxylic acid, 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-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 benzophenone-4,4'-dicarboxylic acid, phthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, adipic acid, succinic acid, maleic acid , cepatic acid, isosepatic acid, dimer acid, tetrachlorophthalic acid, 4.4'-dicarboxy-diphenylmethane, 4.4
'-dicarboxy-diphenylpropane and the like.

Next, as derivatives of the above-mentioned dihydric carboxylic acids, first there are esters, examples of which include lower dialkyl esters of the above-mentioned carboxylic acids, such as terephthalic acid, dimethyl terephthalate, diethyl terephthalate, dipropyl terephthalate, dibutyl terephthalate, and esters. Examples include mil terephthalate, diethyl terephthalate, dioctyl terephthalate, or half esters thereof, such as monomethyl terephthalate.

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

Furthermore, it is possible to use not only the above-mentioned carboxylic acids and their derivatives alone but also mixtures thereof.

Particularly preferred as (A) are isophthalic acid, terephthalic acid, or derivatives thereof, and it is also possible to replace a part of these with other carboxylic acids or derivatives thereof. In addition, some trivalent carboxylic acids or derivatives thereof may be used. For example, it has been found that when trimellitic anhydride is used, the solder removability is improved.

As the divalent carboxylic acid containing a five-membered imide group, its derivative, or a mixture thereof (B), the following (a) and (b) or (a) and (c) can be prepared by a conventionally known method. Examples include those obtained by reaction.

(a) Aromatic carboxylic anhydride containing at least one other reactive group in addition to the five-membered carboxylic anhydride group, where the latter reactive group is a carboxyl group or a carboxylic anhydride group. Or a hydroxyl group, etc.

As long as two carboxyl groups bonded to adjacent carbon atoms or their esters, half esters, and imide groups can be formed in place of the five-membered ring carboxylic acid anhydride group, the following (b) Half-amides with primary amines may also be used.

(b) A primary amine having at least one other reactive group in addition to the primary amino group. This latter reactive group may be a carboxyl group, a hydroxyl group or even a primary amino group.

Insofar as the attached primary amino group can form an imide group instead of a primary amino group,
Salts, amides, lactams or boamides of the amines may also be used.

(c) Polyisocyanate Examples of the compound (a) having a five-membered carboxylic acid anhydride group and other functional groups include tricarboxylic anhydrides, such as trimellitic anhydride, hemimellitic anhydride, 1.2.5-Naphthalenetricarboxylic anhydride, 2.3
．． 6-Naphthalenetricarboxylic anhydride, 1.8.4-
naphthalenetricarboxylic anhydride, 3.4.4'-diphenyltricarboxylic anhydride, 3.4.4''-diphenylmethanetricarboxylic anhydride, 3.4.4'-diphenyl ethertricarboxylic anhydride, 3.4.4'-benzophenonetricarboxylic anhydride and the like.

Examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, merophadiic dianhydride, 2.3,6.7-naphthalenetetracarboxylic dianhydride, and 1.8,4.5-naphthalene. Tetracarboxylic dianhydride, 1, Z, 5.6-naphthalene tetracarboxylic dianhydride, 3.3', 4.4''-diphenyltetracarboxylic dianhydride, 3.3', 4.4 '-diphenyl ether tetracarboxylic dianhydride, 3.3',4.4'-diphenylmethanetetracarboxylic dianhydride, 3.3',4.4'-hensiphenotetracarboxylic dianhydride A particularly useful one is trimellitic anhydride.

Examples of the compound (b) having at least one primary amino group and other functional group include ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, and hexamethylenediamine.

Aliphatic diamines such as heptamethylene diamine and octamethylene diamine, 4.4'
-diaminodiphenylmethane, 4.4'-diaminodiphenylpropane, 4.4'-diaminodiphenyl sulfide, 4.4'-diaminodiphenyl sulfone, 4.4
'-Diamino diphenyl ether, 3.3'-diaminodiphenyl.

3.3'-diaminodiphenylsulfone, 3.3'-dimethyl-4,4'-bisphenyldiamine, 1.4-diaminonaphthalene, 1.5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, Aromatic primary diamines such as m-xylylene diamine, p-xylylene diamine, l-isopropyl-2,4-metaphenylene diamine, and further, for example, 3-(p-aminocyclohexyl)methanediaminopropyl, 3- Methyl-heptanemethylenediamine, 4,4'-dimethylhexamethylenediamine, 2,5-dimethylhexamethylenediamine.

Branched aliphatic diamines such as 2,5-dimethylhebutamethine diamine, further alicyclic diamines such as 1,4-diaminocyclohexane, 1,10-diamino-1,10-dimethyldecane, furthermore, Amino alcohols such as, for example, monoethanolamine, motuprobanolamine, dimethylethanolamine, and aminocarboxylic acids such as, for example, glycocol, aminopropionic acid, aminocaproic acid, aminobenzoic acid may also be used, but particularly preferred are It is an aromatic diamine.

Examples of the compound of polyisocyanate (c) include mononuclear polyisocyanates, such as m-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, etc. Examples of aromatic polyisocyanate compounds having multiple nuclei include ' diphenyl ether-4,4'-diisocyanate diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyane-diphenylmethane-2,2'-diisocyanate , diphenylsulfone-4,4'-diisocyanate, diphenylthioether-4,4'-diisocyanate, naphthalene diisocyanate, and further examples include hexamethylene diisocyanate.

In addition, so-called stabilized isocyanates in which the isocyanate groups of these polyisocyanates are stabilized with phenolic hydroxyl groups can also be used.

The most preferred divalent carboxylic acids containing a five-membered imide group are 2 moles of trimellitic anhydride, 1 mole of 4.4'-diaminodiphenylmethane, 1 mole of 4.4'-diaminodiphenyl ether, and 4 diphenylmethane. , 1 mol of 4'-diisocyanate or diphenyl ether-4,4'-
It is a dihydric carboxylic acid obtained from 1 mole of diisocyanate. These dihydric carboxylic acids containing a five-membered imide group are usually obtained by reacting (a) and (b) or (a) and (c) in a solvent.

Examples of the solvent used when obtaining a divalent carboxylic acid containing a five-membered imide group in a solvent include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, N,N -diethylformamide, N,
N-diethylacetamide, cresylic acid, phenol, 0-cresol, m-cresol, P-cresol,
2゜3-xylenol, 2.4-xylenol, 2゜5
-xylenol, 2.6-xylenol, 3°4-xylenol, 3.5-xylenol, aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, ethers, ketones and esters can also be used, Examples of these include benzene, toluene, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, petroleum naphtha, coal tar naphtha, solvent naphtha, acetone, methyl ethyl ketone, methyl isobutyl ketone,
Examples include methyl acetate and ethyl acetate. These solvents can be used not only alone but also as a mixed solvent.

Examples of divalent carboxylic acid derivatives containing a five-membered imide group include esters and halides.

Trihydric alcohol (C), which is a reaction product of trimellitic anhydride and dihydric alcohol, can be obtained by reacting trimellitic anhydride with the following dihydric alcohol (D) by a conventionally known method. Here are the things you can get.

Particularly preferred as (C) are triethylene glycol trimellitate and trihexanediol trimellitate.

Examples of dihydric alcohols (D) include: ethylene glycol.

diethylene glycol, Triethylene glycol.

Tetraethylene glycol, 1,2'-propylene glycol, dipropylene glycol, 1,3-propanediol, various butane-, pentane- or hexanediols, such as 1,3- or 1,4-butanediol, 1. 5-bentanediol 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-butynediol, water-added bisphenols (e.g., 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 -Cyclohexane dimetatool, 1,4-cyclohexane jetanol, 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 used in the present invention refers to one that does not contain aromatic or heterocyclic rings at any position in the molecule. When a trihydric alcohol or a tetrahydric or higher alcohol containing an aromatic or heterocyclic ring is used, it is not preferable to add it because the solder removability will be significantly impaired.

Examples of these trihydric aliphatic alcohols (E) are:
For example, glycerin, 1.1. Examples include i-trimethylolethane, i,l,1-trimethylolpropane, and particularly preferred is glycerin.

In the present invention, the following method may be mentioned as an embodiment of synthesizing a polyesterimide resin using these raw material compounds.

(1) Dihydric carboxylic acid containing a five-membered imide group (B
) is reacted with the raw materials (a) and (b) or (a) and (c) mentioned above in the section of the dihydric carboxylic acid (B) containing a five-membered imide group in a solvent. By adding other raw materials (A), (C), (D) and (E) to this system and proceeding with the esterification reaction at 200 to 210°C for 3 to 7 hours. , a method for synthesizing polyesterimide resin.

(2) Divalent carboxylic acid containing a five-membered imide group (B
) is formed by reacting the raw materials (a) and (b) or (a) and (c) mentioned in the section of the dihydric carboxylic acid (B) containing a five-membered imide group in a solvent. Then, a polyester intermediate synthesized from other raw materials (A), (C), (D), and (E) was added to this system, and 20
A method of synthesizing a polyesterimide resin solution by conducting an ester reaction at 0 to 210°C for 3 to 5 hours.

(3) In the system of the polyester intermediate obtained by the method (2) above, the above raw materials (a) and (b) or (a) and (
c) Divalent carbon containing a five-membered imide group synthesized from a! A method of synthesizing a polyesterimide resin solution by adding 2(B) and proceeding with an esterification reaction at 200 to 210°C for 3 to 5 hours.

(4) The polyester intermediate solution obtained by the method (2) above is cooled to below io0°C, and the polyester intermediate solution obtained by the above (
A) and (B) are added to form a dihydric carboxylic acid (B) containing an imide group at 120 to 160°C, and the temperature is raised to 200°C, and 3 to 5 A method of synthesizing a polyesterimide resin solution by proceeding with a time esterification reaction.

(5) Divalent carboxylic acid containing a five-membered imide group (B
) The starting materials (a) and (b) and other raw materials (A), (C), (D> and (E)) are mixed simultaneously, and in this system 120 The imidization reaction was carried out at 160°C to 160°C, and the temperature was raised to 200°C.
There is a simultaneous reaction method in which a polyesterimide resin solution is synthesized by carrying out a direct esterification reaction at a temperature of 3 to 5 hours at a temperature of 210°C to 210°C.

Raw materials (A), (B), (C), (0) and (
The polyesterimide resin obtained by the reaction E) can be used in any field where heat resistance is required, but the most preferred field of use is as a main component of insulating paint for electric wires. .

An insulating coating material can be obtained by dissolving the polyesterimide resin of the present invention described above in a solvent or adjusting the concentration to an appropriate level.

Examples of the solvent include solvents having phenolic hydroxyl groups, such as phenol, 0-cresol, m-cresol,
p-cresol, 2.3-xylenol, 2,4-xylenol, 2.5-xylenol, 2.6-xylenol, 3.4-xylenol, 3.5-xylenol, o
-n-propylphenol, 2,4.6-trimethylphenol, 2,3.5-trimethylphenol, 2゜4
．． Preference is given to using 5-trimethylphenol, 4-ethyl-2-methylphenol, 5-ethyl-2-methylphenol and mixtures thereof, cresylic acid. In addition, polar solvents such as N-methyl-2-pyrrolidone and N,N-dimethylacetamide can be used.

Further, as the diluting solvent, for example, aliphatic hydrocarbons, aromatic hydrocarbons, ethers, acetals, ketones, esters, etc. can be used.

Examples of aliphatic hydrocarbons and aromatic hydrocarbons include:
n-hebutane, n-octane, cyclohexane, decalin, dipentene, pinene, p-menthane, decane, dodecane, tetradecane, benzene, toluene, xylene,
Examples include ethylbenzene, diethylbenzene, isopropylbenzene, amylbenzene, p-cymene, tetralin, or mixtures thereof.1 Petroleum naphtha, coal tar naphtha, and solvent naphtha.

The most useful solvent for insulating coatings using the polyesterimide resin of the present invention is cresylic acid. Cresylic acid is 1
It has a boiling point range of 80 to 230°C, and contains phenol, o-cresol, m-cresol, p-cresol, and xylenols.

By diluting a portion of this cresylic acid with an aromatic hydrocarbon such as petroleum naphtha, coal tar naphtha, solvent naphtha, etc., the workability of manufacturing insulated wires by coating and baking an insulating paint on a conductor is improved. can be improved.

These diluting solvents include, for example, xylene, solvent naphtha No. 2, Tsurupetz #100, and Tsurupetz #
150, etc., and the amount used is 0% of the weight of the solvent.
The content ranges from 30% to 30%, preferably from 10 to 20%.

When manufacturing an insulated wire by coating and baking the insulating paint containing the resin of the present invention obtained in this way on a conductor, using a small amount of metal desiccant improves the surface smoothness of the insulated wire, and This is preferable because the take-up speed can be increased and the workability is further improved.

As these metal desiccants, zinc, calcium or lead octoate, lyruto, etc. are useful, such as zinc octoate, calcium naphthinate, zinc naphthinate, lead naphthinate, lead tinonate, calcium lylate, zinc resinate, etc. Others include manganese naphthenate, cobalt naphthinate, etc.

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

Typical titanic acid compounds include, for example, tetraalkyl titanates such as tetraisopropyl titanate, tetrabutyl titanate, tetrahexyl titanate, tetramethyl titanate, tetrapropyl titanate, and tetraoctyl titanate.

Also useful are tetraalkyl titanium chelates obtained by reacting tetraalkyl titanates with octylene glycol, triethanolamine, 2,4-pentadiene, acetoacetate, and the like.

Also useful are tetraalkyl titanium acylates obtained by reacting tetraalkyl titanates with stisaaric acid and the like.

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

The amount of these metal compounds added is 0.1 to 6.0% by weight, preferably 1 to 3% by weight based on the solid content of the insulating coating.
Weight%.

Further, as a curing agent, a stabilized polyisocyanate in which the isocyanate groups of polyisocyanate are blocked with phenol, cresol, etc. can be used. Examples of these include 2.4-tolylene diisocyanate with 2.6-
Cyclic trimer of tolylene diisocyanate, trimer of diphenylmethane-4,4'-diisocyanate, reaction product of 3 moles of diphenylmethane-4,4'-diisocyanate and 1 mole of trimethylolpropane, Reaction product of 3 moles of 2.4-)lylene diisocyanate and 1 mole of trimethylolpropane, 3 moles of 2,
6-Reaction product of 1-lylene diisocyanate and 1 mole of trimethylolpropane, reaction product of 3 moles of 2.4-tolylene diisocyanate and 1 mole of trimethylolethane, 3 moles of 2.6-1 reaction product of lylene diisocyanate and 1 mole of trimethylolethane,
Reaction product of 3 moles of mixed 2,4- and 2,6-tolylene diisocyanate and 1 mole of trimethylolpropane.

Examples include stabilized polyisocyanates obtained by blocking mixed cyclic trimers of 2,4- and 2,6-tolylene diisocyanates with phenol or cresol. Also useful are stabilized isocyanates prepared by blocking diphenylmethane-4,4'-diisocyanate with xylenol.

In addition, 1 to 5% by weight of phenol-formaldehyde resin, melamine-formaldehyde resin, talesol-formaldehyde resin, xylene-formaldehyde resin, urea-formaldehyde resin, epoxy resin, and silicone resin are added to the titanium-based compound or polyisocyanate (or By adding it together with its derivative), the appearance and workability of the insulated wire can be further improved. If the amount of these resins is less than 1% by weight, there is no effect in improving workability, and if the amount of crosslinking exceeds 5% by weight, carbides are formed significantly during solder removal, which is not preferable. Particularly preferred resins are phenol-formaldehyde resin and xylene-formaldehyde resin, and these resins! By adding 2% to 2% by weight, the appearance and workability of the insulated wire can be improved without impairing the solder removability of the insulated wire.

The above is the content of the insulating paint containing the polyesterimide resin of the present invention, and a heat-resistant insulated wire made of the insulating paint can be provided by applying and baking the polyesterimide insulating paint onto a conductor to obtain a predetermined film thickness. be done.

The conductor used in this case is, for example, copper, silver, aluminum, or stainless steel wire, and the applicable conductor diameter may be any diameter from ultra-thin wire to thick wire, and is limited to a specific conductor diameter. It is not something that will be done. -Numerically, the diameter is about 0.050 to 2. It is mainly used for copper wires of about Oa+m.

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

(Effects) According to the present invention as described above, a solderable heat-resistant insulated wire with significantly improved softening temperature and solder removability is economically provided.

The content of the present invention will be specifically explained in the following reference examples, comparative examples, and examples, but the present invention is not limited to these examples.

Reference Example 1 192 g (1.0 mol) of trimellitic anhydride was added to 600 g of cresol, then 99 g (0.5 mol) of 4,4'-diaminodiphenylmethane was added, and the mixture was heated to 140°C. The mixture was reacted for 6 hours. After cooling, a pale yellow, fine crystal precipitate was obtained. This was washed several times with alcohol and separated by filtration to obtain a five-membered ring diimide dicarboxylic acid.

Reference Example 2 192 g (1.0 mol) of trimellitic anhydride was added to 600 g of cresol, then 100 g (0.5 mol) of 4,4'-diaminodiphenyl ether was added,
This mixture was reacted at 180°C for 4 hours. After cooling, a brown crystalline precipitate was obtained. This was washed several times with alcohol and separated by filtration to obtain a five-membered ring diimide dicarboxylic acid.

Reference Example 3 192 g (1.0 mol) of trimellitic anhydride was added to 600 g of cresol, then 4 g (0.5 mol) of 4,4'-diaminodiphenylsulfone tz was added, and the mixture was heated at 160°C. The reaction was carried out for 4 hours. A white crystalline precipitate was obtained after cooling. This was washed several times with alcohol and separated by filtration to obtain a five-membered ring diimide dicarboxylic acid.

Reference Example 4 192 g (1.0 mol) of trimellitic anhydride was added to 600 g of cresol, then 108 g (0.5 mol) of P-phenylenediamine was added, and the mixture was heated at 180°C for 4 hours. I reacted. A brown crystalline precipitate was obtained after cooling. This was washed several times with alcohol and separated by filtration to obtain a five-membered ring diimide dicarboxylic acid.

Reference Example 5 192 g (1.0 mol) of trimellitic anhydride was added to 600 g of cresol, then 58 g (0.5 mol) of hexamethylene diamine was added, and the mixture was heated to 180 g.
The reaction was carried out at ℃ for 4 hours. A white crystalline precipitate was obtained after cooling. This was washed several times with alcohol and separated by filtration to obtain a five-membered ring diimide dicarboxylic acid. ' Reference Example 6 192 g (1.0 soles) of trimellitic anhydride and 137 g (1.9 moles) of p-aminobenzoic acid were mixed into cresol 6
00g and dispersed. This mixture was heated to 150°C.
The reaction was carried out for 4 hours. After cooling, a fine precipitate of white powder was obtained. This was washed several times with alcohol and separated by filtration to obtain a five-membered ring diimide dicarboxylic acid.

Reference Example 7 192 g (1.0 mol) of trimellitic anhydride and 125 g (1.0 mol) of diphenylmethane-4,4'-diisocyanate (
0.5 mol) was added to 150 g of solvent naphtha (Mega Kagaku Hysol #100), and the mixture was reacted at 150° C. for 4 hours.

As the reaction proceeded, significant foaming occurred and then solidification occurred. This solidified product was pulverized to obtain a five-membered diimide dicarboxylic acid.

Reference Example 8 192 g (1.0 mol) of trimellitic anhydride and 18.3 g (3.0 mol) of ethyl chloride
The esterification reaction was carried out at 70 to 180° C. for 3 hours until the acid value became 30 or less.

The acid value of the obtained triethylene glycol trimellitate was 25.

Reference example 9 192g (1.0 mol) of trimellitic anhydride and 1.6
- 354 g (3.0 mol) of hexanediol and 17
The esterification reaction was carried out at 0 to 180° C. for 3 hours until the acid value became 30 or less.

The acid value of the obtained trihexanediol trimellitate was 28.

Example! 3 equipped with a stirrer, nitrogen gas inlet pipe, thermometer and cooling pipe
In the same manner as in Reference Example 1, 192 g (1.0 mol) of trimellitic acid anhydride was added to 600 g of cresol and dispersed in a fourth 000cc flask. Next, 4.
99 g (0.5 mol) of 4'-diaminodiphenylmethane are added and the mixture is reacted at 150 DEG C. for 3 hours to obtain 273 g (1.0 equivalent) of five-membered diimidodicarboxylic acid. After cooling this system to below 100°C, 582 g (6,0 equivalent N) of dimethyl terephthalate, Reference Example 8
Triethylene glycol trimellitate/lz34
2 g (3,0 equivalents), ethylene IJ:ff-le 9
3 g (: 1.0 equivalent), 186 g (6.0 equivalent) of glycerin, and 120 g of xylene were added, mixed and stirred until 20
The temperature was raised to 0° C. over 6 hours, and the reaction was continued at this temperature for 5 hours.

This five-membered ring diimide dicarboxylic acid reacts with the produced polyester component to obtain a transparent resin solution. The degree of reaction was measured by the increase in viscosity, and samples were collected over time. The end point of the reaction is when the viscosity of the resin sample becomes 12 to z3 (Gardner viscometer) in 40% cresol, then cresol is added to make the non-volatile content 40%, and Shiraishi Kagaku Hysol #100 is added to this to make the non-volatile content 35%. Make a resin solution.

Furthermore, 2% tetrabutyl titanate and t based on the resin content
2% of a phenol-formaldehyde resin containing .

Example 2 3 equipped with a stirrer, nitrogen gas introduction pipe, thermometer and cooling pipe
In the same manner as in Reference Example 1, 192 g (1.0 mol) of trimellitic acid anhydride was added to 600 g of cresol and dispersed in a 0OOcc four-loaf flask. Next 4.4
'-Diaminodiphenylmethane 99g (0.5 mol)
was added, and this mixture was reacted at 150°C for 3 hours to produce 273 g (1,0 equivalent f) of five-membered diimidodicarboxylic acid.
f1) is obtained. After cooling this system to below 100°C, 582 g (6.0 equivalents) of dimethyl terephthalate and 342 g (342 g) triethylene glycol trimellitate according to Reference Example 8 were placed in a 1,500 cc reaction vessel similar to the above.
3.0 equivalent), ethylene glycol 93g (:1.0
(equivalent), 186 g (6.0 eq.) of glycerin, and 120 g of xylene were mixed and stirred, heated to 200° C. over 6 hours, and reacted at this temperature for 5 hours.

After cooling this polyester component to 80°C, 1,01
Upon addition of 0 g, the reaction is started again. The reaction is 20
It takes 5 to 7 hours to reach 0°C. This five-membered ring diimide dicarboxylic acid reacts with the polyester component to obtain a transparent resin solution. The degree of reaction was measured by the increase in viscosity, and samples were collected over time. The end point of the reaction is when the viscosity of the resin sample reaches z2 to z3+ (Gardner viscometer) in 40% cresol, then cresol is added to make the non-volatile content 40%, and Shiraishi Kagaku Hysol #100 is added to this to make the non-volatile content 35%. Make a resin solution.

Furthermore, 2% tetrabutyl titanate and t based on the resin content
Phenol whose main component is ert-butylphenol
An insulating paint containing the polyesterimide resin of the present invention was prepared by adding 2% formaldehyde resin.

Example 3 2 equipped with a stirrer, nitrogen gas introduction pipe, thermometer and cooling pipe
, 582 g (6,0 equivalents) of dimethyl terephthalate and 342 g (3,0 equivalents) of triethylene glycol trimellitate according to Reference Example 8 were placed in a 000 cc four-bottle flask.
, ethylene glycol 93g (3,0 equivalents), ethylene glycol 93g (3,0 equivalents), glycerin 186g
(6.0 equivalent N) and 120 g of xylene were mixed and stirred and reacted at 200° C. over 6 hours to synthesize a polyester component. After adding 300g of cresol to this and cooling it to 80℃, trimellitic anhydride 19
2 g (1.0 mol) and 96 g (0.5 mol) of 4,4'-diaminodiphenylmethane were added, and the reaction temperature was increased to 2.
Raise the temperature to 00°C. During this time, five-membered ring diimidodicarboxylic acid (1,0 equivalent) is generated and precipitated at 140 to 150°C, so the system becomes cloudy and highly viscous, but as the temperature rises, it is absorbed by the polyester component and becomes a solution. Then, it becomes a transparent resin solution. Reaction temperature 200℃
The extent of the zero reaction is measured by the increase in viscosity, and the end point of the zero reaction when samples are collected over time is when the viscosity of the resin sample is 22 (Gardner viscometer) in 40% cresol. When the temperature reached 7, cresol was added to make the non-volatile content 40%, and Ogoku Kagaku Hysol #100 was added to this to make a resin solution with a non-volatile content of 35%.

The resin solution thus obtained was treated as in Example 1 to obtain an insulating paint containing the polyesterimide resin of the present invention.

Example 4 2 equipped with a stirrer, nitrogen gas introduction pipe, thermometer and cooling pipe
, 000 cc fourth flask, 582 g (6.0 equivalents) of dimethyl terephthalate, 342 g (1.0 equivalents) of triethylene glycol trimellitate according to Reference Example 8, 93 g (3,0 equivalents) of ethylene glycol, 186 g of glycerin. (6.0 equivalent) and 120 g of xylene were mixed and stirred and reacted at 200° C. over 6 hours to synthesize a polyester component. Add 300g of cresol to this
After cooling to 80° C., 273 g of the five-membered ring diimidodicarboxylic acid obtained in Reference Example 1 (1,0
equivalent amount) and the reaction temperature is raised to 200° C. over 1 to 2 hours. During this time, the system is cloudy, but as the temperature rises, it is absorbed by the polyester component and becomes a solution, and then becomes a transparent resin solution. The reaction temperature is maintained at 200° C. for 2 to 3 hours. The degree of reaction was measured by the increase in viscosity, and samples were collected over time.

The end point of the reaction is when the viscosity of the resin sample is 2 in 40% cresol.
2 (Gardner viscometer), add cresol to make the non-volatile content 40%, and add the above-mentioned Hysol #100 to make a resin solution with a non-volatile content of 35%.

The resin solution thus obtained was treated as in Example 1 to obtain an insulating paint containing the polyesterimide resin of the present invention.

Example 5 2 equipped with a stirrer, nitrogen gas introduction pipe, thermometer and cooling pipe
, 582 g (6,0 equivalents) of dimethyl terephthalate and 342 g (3,0 equivalents) of triethylene glycol trimellitate according to Reference Example 8 were placed in a 000 cc four-bottle flask.
, 93 g of ethylene glycol (3,0 equivalents 1[), 186 g of glycerin (6,0 equivalents), 192 g of trimellitic anhydride (1,0 equivalents), 99 g of 4,4'-diaminodiphenylmethane (0,5 moles) ), cresol 300g
Add 120g of xylene, mix and stir and heat to 200°C.
Wait for 6 hours to raise the temperature. During this time, a five-membered ring diimide dicarboxylic acid is produced at 140° C., and as a result of precipitation, it becomes cloudy and exhibits high viscosity. As the temperature rises, the five-membered ring diimide dicarboxylic acid precipitated is gradually absorbed into the polyester component. The degree of zero reaction that continues the reaction at 200°C for 5 hours is
Samples were collected over time to measure the increase in viscosity. The end point of the reaction is when the viscosity of the resin sample becomes z2+ (Gardner viscometer) in 40% cresol, then cresol is added to make the non-volatile content 40%, and to this the above-mentioned Hysol #100 is added to make the non-volatile content 35%. resin solution.

The resin solution thus obtained was treated as in Example 1 to obtain an insulating paint containing the polyesterimide resin of the present invention.

Example 6 Diimidodicarboxylic acid 27 of Reference Example 2 was used instead of diimidodicarboxylic acid of Reference Example 1 in the formulation example of Example 4.
An insulating paint containing the polyesterimide resin of the present invention was obtained using 4 g.

Example 7 Diimidodicarboxylic acid 29 of Reference Example 3 was used instead of diimidodicarboxylic acid of Reference Example 1 in the formulation example of Example 4.
Using 8 g, an insulating paint containing the polyesterimide resin of the present invention was obtained.

Example 8 Diimide dicarboxylic acid 28 of Reference Example 4 was used instead of diimide dicarboxylic acid of Reference Example 1 in the formulation example of Example 4.
Using 2 g, an insulating paint containing the polyesterimide resin of the present invention was obtained.

Example 9 Diimidodicarboxylic acid 23 of Reference Example 5 was used instead of diimidodicarboxylic acid of Reference Example 1 in the formulation example of Example 4.
Using 2 g, an insulating paint containing the polyesterimide resin of the present invention was obtained.

Example 10 Diimidodicarboxylic acid 15 of Reference Example 6 was used instead of diimidodicarboxylic acid of Reference Example 1 in the formulation example of Example 4.
Using 6 g, an insulating paint containing the polyesterimide resin of the present invention was obtained.

Example 11 Diimidodicarboxylic acid 27 of Reference Example 7 was used instead of diimidodicarboxylic acid of Reference Example 1 in the formulation example of Example 4.
Using 3 g, an insulating paint containing the polyesterimide resin of the present invention was obtained.

Example I2 Dimethyl terephthalate in the formulation example of Example 4) 58
291 g (3,0 equivalents) of dimethyl terephthalate and isophthalic acid zs9 instead of 2 g (6,0 equivalents N)
g (3.0 equivalents) to obtain an insulating paint containing the polyesterimide resin of the present invention.

Example 13 2 equipped with a stirrer, nitrogen gas introduction pipe, thermometer and cooling pipe
, 485 g (5,0 equivalents) of dimethyl terephthalate and 342 g (3,0 equivalents) of triethylenegutucol trimellitate according to Reference Example 8 were placed in a 000 cc four-bottle flask.
, 93 g (3.0 equivalents) of ethylene glycol, 186 g (6.0 equivalents) of glycerin, and 120 g of xylene were mixed and stirred and reacted at 200° C. over 6 hours to synthesize a polyester component. After adding 300 g of cresol and cooling to 80°C, 384 g (2.0 mol) of trimellitic anhydride and 198 g (1.0 mol) of 4°4'-diaminodiphenylmethane were added,
The reaction temperature is raised to 200°C. 140~ during this time! At 50°C, five-membered ring diimidodicarboxylic acid (2.0 equivalents) is formed and precipitated, making this system cloudy and highly viscous, but as the temperature rises, it is absorbed by the polyester component and becomes a solution, and then becomes transparent. It becomes a resin solution. The reaction temperature is maintained at 200° C. for 1 to 2 hours. The degree of reaction is
Samples were collected over time to measure the increase in viscosity. The end point of the reaction is when the viscosity of the resin sample becomes Z2 (Gardner viscometer) in 40% cresol, then cresol is added to make the nonvolatile content 40%, and this is mixed with Meka Kagaku Hysol #.
100 was added to make a resin solution with a nonvolatile content of 35%.

The resin solution thus obtained was treated as in Example 1 to obtain an insulating paint containing the polyesterimide resin of the present invention.

Example 14 Dimethyl terephthalate 4 in the formulation example of Example 13
291 g (3,0 eq.) of dimethyl terephthalate and 1 phthalic anhydride instead of 85 g (5,0 eq. Sk)
4Bg (2.0 equivalents) was used to prepare an insulating paint containing the polyesterimide resin of the present invention.

Example 15 In place of 342 g (3,0 equivalents) of triethylene glycol trimellitate according to Reference Example 8 in the formulation example of Example 13, 492 g (3,0 equivalents) of trihexane glycol trimellitate according to Reference Example 9 was used. Thus, an insulating paint containing the polyesterimide resin of the present invention was prepared.

Example 16 9 jg of ethylene glycol in the formulation example of Example 13
(1,0 equivalent) instead of propylene glycol tt
tg (3.0 equivalents) was used to prepare an insulating paint containing the polyesterimide resin of the present invention.

Example 17 93 g of ethylene glycol in the formulation example of Example 13
(3.0 equivalents), 177 g (3.0 equivalents) of 1,6-hexanediol was used to prepare an anti-absorbent resin containing the polyesterimide resin of the present invention. j paint.

Example 18 Glycerin 186g (s
, o equivalents), 270 g (6,0 equivalents) of 1,1,1-trimethylolpropane was used to prepare an insulating paint containing the polyesterimide resin of the present invention.

Example 19 (dimethyl terephthalate) 398 g (4.0 equivalents), triethylene glycol trimellitate 34 according to Reference Example 8
2g (: 1.0 equivalent), 47g (1.0 equivalent) of ethylene glycol
, 5 equivalents), 233 g (7,5 equivalents) of glycerin, 576 g (3,0 mol) of trimellitic anhydride, and 4.4
An insulating paint containing the polyesterimide resin of the present invention was prepared in the same manner as in Example 4 using 297 g (1.5 moles) of '-diaminodiphenylmethane.

Example 20 Dimethyl terephthalate 194 g (2,0 equivalents), triethylene glycol trimellitate according to Reference Example 8 34
2g (3,0 equivalents), 130g ethylene glycol (4
, 2 equivalents), 211 g (6,8 equivalents) of glycerin, 960 g (5,0 mol) of trimellitic anhydride, and 4.4'
-495 g (2.5 mol) of diaminodiphenylmethane
An insulating paint containing the polyesterimide resin of the present invention was prepared in the same manner as in Example 4.

Example 21 291 g (3,0 equivalents) of dimethyl terephthalate, 45 triethylene glycol trimellitate according to Reference Example 8
6g (4,0 equivalents), 121g ethylene glycol (3
, g equivalent), 158 g of glycerin (5,1 equivalent) and Trimerit WR5F! 576 g (3,0 mol) of monohydrate and 297 g (1,0 mol) of 4,4'-diaminodiphenylmethane.
An insulating paint containing the polyesterimide resin of the present invention was prepared in the same manner as in Example 4 using 5 mol).

Comparative Example 1 3 equipped with a stirrer, nitrogen gas introduction pipe, thermometer and cooling pipe
, 776 g (8.0 equivalents) of dimethyl terephthalate, 2 ethylene glycol,
60 g (8.4 equivalents), 174 g (5.6 equivalents) of glycerin, 0.8 g of litharge, and 150 g of xylene were mixed and stirred and reacted at 200° C. over 6 hours to synthesize a polyester component. After adding 370 g of cresol and cooling to 80°C, 546 g (2.0 equivalents) of the five-membered ring diimidodicarboxylic acid obtained in Reference Example 1 was added, and the reaction temperature was raised to 200°C. Heat up over time. During this time, this system is cloudy, but as the temperature rises, it is absorbed by the polyester component and becomes a solution.
A clear resin solution is then obtained. After raising the reaction temperature to 240°C and keeping the temperature for 2 to 3 hours, vacuum distillation is performed. When it becomes sufficiently viscous, cresol is added to make the non-volatile content 40%, and 8 Stone Chemical Hysol #100 is added to this to make it non-volatile. 35% resin solution.

Furthermore, 3% of the resin content of tetrabutyl titanate was added to obtain an insulating paint as a comparative example.

Comparative Example 2 3 equipped with a stirrer, nitrogen gas introduction pipe, thermometer and cooling pipe
, 388 g of dimethyl terephthalate (4.0 equivalents), 233 g of ethylene glycol (7.5 equivalents), and 2.33 g of glycerin in a 000 cc four-bottle flask.
(7,5 equivalents), Resurge 0.4g and Xylene 80
A polyester component was synthesized by mixing and stirring and reacting at 200° C. for 6 hours. Add 5 cresol to this
After adding 60g and cooling to 80°C, 1.152g (6.0 mol) of trimellitic anhydride and 4,
594 g (3.0 mol) of 4'-diaminodiphenylmethane were added, and the reaction temperature was raised to 200°C.

During this time, at 140 to 159°C, five-membered diimide dicarbonate Wn (6, (l equivalent)) is formed and precipitated, making the system cloudy and highly viscous, but as the temperature rises, it is absorbed by the polyester component and becomes a solution. , then a transparent resin solution is obtained.The reaction temperature is raised to 240°C and 1
After keeping the temperature for 2 hours, distillation was carried out under reduced pressure, and when it became sufficiently viscous, cresol was added to make the nonvolatile content 40%. Add Shiraishi Kagaku Hisol #100 to this to make the non-volatile content 35%.
resin solution. Furthermore, 3% of the resin content of tetrabutyl titanate was added to obtain an insulating paint as a comparative example.

Comparative Example 3 155 g (5.0 equivalents) of ethylene glycol from Comparative Example 2
295 g of 1,6-hexanediol (5,0
An insulating paint of a comparative example was obtained in the same manner as in Example 2 using 0 equivalent).

In performing performance tests on these insulating paints, insulated wires were manufactured by applying and baking insulating paints containing polyesterimide resins of the present invention and comparative examples under the following conditions.

Conductor diameter; 1. OOm/m Baking furnace: Vertical baking furnace with primary furnace length of 2.5 m Baking temperature: 45
0°C (maximum temperature) Drawing method: die method Number of applications: 6 times Film thickness: o, 035 to 0.039 m/m The test method was conducted in accordance with the JTSC3003-1984 enameled copper wire and enameled aluminum wire test method. . The test results are shown in Table 1.

As is clear from the above test results, when the insulating paint containing the polyesterimide resin according to the present invention is used, the softening temperature and solder removability are lower than those using the conventional insulating paint containing the polyesterimide resin. It is clear that there has been a significant improvement.

(Margin below) Negative λ-1-1〈Of+Gekisei (with normal winding) Id ld
ld Id ld Id Id
Id ld dense 1i sex (SuddenJerk)
o, k o, k o, k o, k o, k
o, k o, k o, k o, soft E name-J
Similar WL Near 00g): 1S215:1342:15:1
35ko 353342320: 154 harou t2E (sigh K
V) 10.110-611.210.810.51
+, 110.211.2 9.8 resistance WJ offshore [(-one-way type: g) 1600 1620 1550 1580
16:10 1540 162014 (fund) 159
0% formula%: 3

Claims (6)

[Claims] (1) (A) A divalent carboxylic acid or a derivative thereof that does not contain a five-membered imide group, or a mixture thereof; (B) A divalent carboxylic acid or a derivative thereof that contains a five-membered imide group, or a mixture thereof. a mixture; (C) a trihydric alcohol which is a reaction product of trimellitic acid or trimellitic anhydride and a dihydric alcohol; (D) a dihydric alcohol; and (E) a trihydric aliphatic alcohol. A polyesterimide resin obtained by reaction in the presence of an organic solvent. (2) Claims in which the divalent carboxylic acid that does not contain a five-membered imide group is terephthalic acid or its lower alkyl ester, isophthalic acid or its lower alkyl ester, phthalic acid or its anhydride, or a mixture thereof. The polyesterimide resin according to item (1). (3) A divalent carboxylic acid containing a five-membered imide group,
The polyesterimide resin according to claim (1), which is a dihydric carboxylic acid obtained by reacting 2 moles of trimellitic anhydride with 1 mole of diamine or diisocyanate. (4) The polyesterimide resin according to claim (1), wherein the dihydric alcohol to be reacted with trimellitic anhydride is ethylene glycol, 1,6-hexanediol, or a mixture thereof. (5) The dihydric alcohol is ethylene glycol, 1,2
- The polyesterimide resin according to claim (1), which is propylene glycol, 1,6-hexanediol or a mixture thereof. (6) The trihydric alcohol is glycerin, 1,1,1-
The polyesterimide resin according to claim (1), which is trimethylolpropane or a mixture thereof.