JPS61179218A - Polyamide-imide resin composition - Google Patents

Abstract

PURPOSE:The title composition excellent in adhesion and flexibility, prepared by mixing a specified resin composition with a resin composition obtained by reacting a polycarboxylic acid (derivative) with a polyalcohol. CONSTITUTION:A resin composition (A) is obtained by reacting a reaction product obtained by reacting 1mol of a tricarboxylic acid (derivative) containing at least 5mol% citric anhydride with at least 1mol of an aromatic diisocyanate (derivative), e.g., 4,4'-diphenylmethane diisocyanate, at 60-350 deg.C for several to several tens of hr in a phenolic solvent (e.g., phenol) with 0.05-0.7mol, per mol of the tricarboxylic acid, of a polyalcohol (e.g., glycol) at 180-250 deg.C for 1-10 and odd hr. 90-10wt% component A is mixed with 10-90wt% resin composition (B) obtained by reacting a polycarboxylic acid (derivative), e.g., terephthalic acid, with a polyalcohol.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel polyamideimide resin composition.

Organic insulating materials used in electrical equipment vary depending on the form used, such as insulated wires, paints, films, laminates, impregnated resins, adhesives, etc., but include phenolic resins, polyvinyl formal resins, polyester resins, alkyd resins, Epoxy resins, polyesterimide resins, polyamideimide resins, polyimide resins, etc. are commonly used.

In recent years, with the need for resource and energy conservation and the miniaturization and weight reduction of peripheral equipment, electrical equipment itself has become more efficient and smaller. The importance of organic materials is increasing.

In the field of insulating paints, polyester resin paints, which have improved heat resistance, have replaced polyester resin paints, which have traditionally been widely used due to their relatively practical balance of heat resistance, mechanical properties, electrical properties, and economic efficiency. The use of imide group-containing resin coatings such as imide, polyamideimide, and polyimide has been increasing in recent years.

Among imide group-containing resins, polyamide-imide resin is known to have the best balance of heat resistance, mechanical properties, electrical properties, and chemical properties.

However, conventional aromatic polyamide-imide resins are only soluble in expensive organic polar solvents such as N-methyl-2-pyrrolidone and dimethylacetamide, and therefore have the disadvantage of increasing the price of resin coatings.

Furthermore, since organic polar solvents have strong hygroscopic properties, paints using organic polar solvents as solvents also have the disadvantage of being difficult to manage during storage and use.

For this reason, in the field of insulated wires, insulated wires using polyesterimide resin paints, which are dissolved in relatively inexpensive phenolic solvents such as phenol, cresol, and xylenol at the expense of heat resistance, and polyester resins, Double-covered wires, in which a polyesterimide resin paint is coated on the lower layer and a polyamide-imide resin is applied and baked on the upper layer, are mainly used. However, the characteristics of insulated wires using polyamide-imide resin paints are increasing. Because of the lack of balance, it has not been possible to satisfy the various demands of current electrical equipment.

Therefore, many proposals have been made for polyamide-imide resins that are partially aliphatic-modified by using amino acids, lactams, etc. as raw materials and have excellent solubility in organic solvents (for example, Japanese Patent Publication No. 56-17374, Equity R13
No. 56-22330, equity 11i? No. 56-34210).

However, when aliphatic modification is performed in which a methylene chain is introduced into the molecule, as is the case with lactam, the heat resistance, especially the heat softening temperature when used as an insulated wire, is inferior to that of aromatic polyamideimide resin. The reality is that it is not possible to obtain a resin that is comprehensively balanced.

The inventor of the present invention continued intensive studies to develop a polyamide-imide resin composition with excellent solubility, and as a result, by using citric acid, which has been rarely considered as a material for heat-resistant resins, They discovered that it was possible to obtain a polyamide-imide resin composition that had superior heat softening properties than aromatic polyamide-imide resins and also had significantly improved solubility in organic solvents, and filed a patent application.

However, the adhesion and flexibility of this material are not necessarily satisfactory, and improvement thereof has been desired.

As a result of various studies on improving the adhesion and flexibility of this polyamide-imide resin, the inventor found that by adding polyhydric alcohol to this polyamide-imide resin and causing a reaction, the heat resistance of the original resin was almost reduced. It has been found that the adhesion and flexibility can be significantly improved without causing any oxidation, and that the polyamide-imide resin modified with polyhydric alcohol in this manner has extremely excellent compatibility with polyester resins.

The present invention was made based on such knowledge, and is a polyamide-imide resin characterized by reacting a tricarboxylic acid containing citric acid and/or its derivative, a diisocyanate and/or its derivative, and a polyhydric alcohol. It is an object of the present invention to provide a resin composition obtained by blending a polyester resin composition into a composition.

The citric acid used in the present invention can be used with or without water of crystallization, but since the reaction with diisocyanate and/or its derivatives involves dehydration, it is preferable to use citric acid with or without water of crystallization from the viewpoint of reaction efficiency. Preference is given to using anhydrous citric acid that does not have any citric acid.

Tricarboxylic acids and/or derivatives thereof other than citric acid include, for example, the following general formulas (I) and (II):
Aromatic citric acid, aromatic tricarboxylic acid ester, and aromatic tricarboxylic acid anhydride represented by these are used alone or as a mixture.

R2 (GOOR+)3・・・・・・・・・・・・・・・
・(I)R+ 0OC-R,, <CO>O...
(II) CO where R+ = Hz alkyl group, phenyl group, (however, X--CH2-1-〇〇-1-802-1-C(CH3
)2-1-〇-) In general, 1-limellitic anhydride is preferred because it has good heat resistance, high reactivity, and economical efficiency.

Note that part of the tricarboxylic acid is replaced by pyromellitic anhydride, 3
．． It is also possible to increase the imide bond ratio and improve heat resistance by substituting with a tetracarboxylic acid or a derivative thereof such as 3',4,4'-benzophenonetetracarboxylic anhydride or butanetetracarboxylic acid.

Conversely, some of the tricarboxylic acids can be replaced with aromatic or aliphatic acids such as terephthalic acid, isophthalic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, and azelaic acid. The ratio of amide bonds can also be increased by substitution with a basic acid.

The proportion of citric acid in the tricarboxylic acid and/or its derivative must be 5 mol % or more in order to sufficiently satisfy the solubility in organic solvents.

If the amount is less than 5 mol %, the solubility in organic solvents, especially phenolic solvents will decrease, making it difficult to obtain a practical resin composition.

As the ratio of citric acid increases, the solubility in organic solvents improves, so it is desirable to adjust the ratio of citric acid as appropriate depending on the form in which the resin composition is used.

The diisocyanate and/or its derivative used in the present invention may be any aliphatic, alicyclic, or aromatic diisocyanate and/or its derivative.

Suitable diisocyanates include ethylene diisocyanate, methylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, trimethylhexamethylene diisocyanate, morpholine diisocyanate, Cyclohexane diisocyanate, 3,9-bis(3-probyl isocyanate)
Aliphatic and alicyclic diisocyanates such as -2,4,8,10-tetraoxaspiro[5.5]undecane; 4.
4'-diphenylmethane diisocyanate, 4,4'
-diphenyl ether diisocyanate, 4.4'
-Diphenylpropane diisocyanate, 4.4'-
Diphenylsulfone diisocyanate, 3,3'-diphenylsulfone diisocyanate, 4,4'-diphenylsulfite diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 3,3'-dichloro-4,4' -diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'
-bisphenyl diisocyanate, 3,3'-dimethoxy-4,4'-bisphenyl diisocyanate,
4.4'-bisphenyl diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 2.4-tolylene diisocyanate, 2,6-tolylene diisocyanate 1~, m-xylylene diisocyanate, p-xylylene diisocyanate, etc. There are several aromatic diisocyanates, which can be used alone or as a mixture of two or more.

Further, diisocyanate derivatives in which the isocyanate group of diisocyanate is masked with phenol, cresol, xylenol, etc. can also be used.

Part of the diisocyanate and/or its derivative 4
．． It can also be replaced with trivalent or higher polyisocyanates such as 4', 4''-triisocyanate-triphenylmethane and 2.2', 5.5'-tetraisocyanate-4,4'-dimethyldiphenylmethane.

Among the isocyanate compounds, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-xylylene diisocyanate, It is desirable to use p-xylylene diisocyanate, 4,4'-diphenyl ether diisocyanate, etc. alone or in combination of two types.

The reaction temperature and reaction time in the reaction of tricarboxylic acids and/or their derivatives, including citric acid, with diisocyanates and/or their derivatives also vary depending on the combination of starting materials and the type of reaction, such as solution reaction or solventless reaction. However, generally the reaction temperature is 60-350℃,
The reaction time ranges from several hours to several tens of hours.

The optimal reaction temperature for solution reactions depends on the type of solvent used,
The decarboxylation reaction between a carboxylic acid or its derivative and a diisocyanate is approximately 70%
The reaction temperature range is from 70 to 250 degrees Celsius, since the reaction starts at around 250 degrees Celsius and most of the organic solvents commonly used in this reaction boil at 250 degrees Celsius or higher.
is preferred.

If the reaction time is extremely long, the isocyanate group and the solvent,
This is not preferable because side reactions such as reactions between isocyanate groups occur, and a range of about several hours to about 30 hours is preferable.

The reaction in the present invention can also be carried out without a solvent, and in this case, the reaction can generally be carried out at a lower reaction temperature and shorter reaction time than in a solution reaction.

However, solution reaction is usually more suitable in consideration of conditions such as ease of obtaining the desired high polymer and how the resin composition is used.

As the solvent used in the solution reaction, almost all organic solvents used in this type of reaction can be used, except for those that react with the starting materials.

Solvents suitable for the present invention include phenol, 0-cresol, m-cresol, p-cresol, various xylenolic acids, various chlorophenols, nitrobenzene, N-methyl-2-pyrrolidone, N,N'-dimethyl Formamide, N.

There are N'-dimethylacetamide, hexamethylphosphoramide, dimethyl sulfoxide, etc. Solvents that can be used in combination with these include benzene, toluene, xylene, and high boiling point aromatic hydrocarbons (for example, Marukubi Sekiyu Co., Ltd.). Suwasol i ooo, Suwasol 1500, Nippon Oil Co., Ltd. 8-koku Hysol 100.8-koku Hisol 150, etc.)
, ethylene glycol motu methyl ether acetate, etc.

A particularly preferred solvent composition is a mixture of a phenolic solvent such as phenol, cresol, xylenol, etc. and a high boiling point aromatic hydrocarbon solvent in view of the stability of the resulting resin solution, film-forming properties, economic efficiency, etc.

There is no particular limit to the solid content concentration during the reaction, but if it is less than 35% by weight, the reaction will take a long time and side reactions will easily occur.
In addition, since a resin composition with a high degree of polymerization cannot be obtained, it is more preferable that the amount is 35% by weight or more.

The reaction in the present invention can be promoted by a catalyst commonly used for the reaction of isocyanes 1 to 1.

Examples of suitable catalysts include - metal salts of naphthenic acids such as lead oxide, boric acid, lead naphthenate, naphthenic acid, zinc, organotitanium compounds such as phosphoric acid, polyphosphoric acid, tetrabutyl titanate, triethanolamine titanate, etc. , triethylamine, 1,8-diaza-bicyclo(5,4,0)undecene-7 (including this acid adduct), and the like.

A suitable amount to be used is 0.01 to 5% by weight based on the solid content at the time of preparation, and there is no particular restriction on the method of addition.

The blending molar ratio of tricarboxylic acid and/or its derivative including citric acid and diisocyanate and/or its derivative is preferably approximately 1:1, but if the excess is about 10 mol% or less, one is used in excess. You can also do that.

Tricarboxylic acid and/or its derivatives including citric acid and diisocyanate and/or its derivatives may be charged simultaneously before the reaction starts, or one may be dissolved in a solvent and the other may be charged at once or in several batches. There are no particular restrictions on the preparation method.

The reaction is controlled within an appropriate range by observing the bubbling of generated carbon dioxide, the culm of the distilled water, and the viscosity of the resin solution.

The polyhydric alcohols used in the present invention include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butanediol, 1,4-butanediol, and 1,3-propane. Diol, neopentyl glycol, 1,6-hexane glycol, trimethylolpropane, trimethylolethane, glycerin, pentaerythritol, 1,5-bentanediol, cyclohexane-1,4-diol, sorbitol, hexitol, erythritol, tris(2)
-Hydroxyethyl)isocyanure-1 and the like.

In order to further improve the compatibility of the polyester resin composition obtained by reacting this resin composition with a polyhydric carboxylic acid and/or its derivative and a polyhydric alcohol, it is necessary to use a trihydric or higher hydric alcohol as the polyhydric alcohol. It is desirable to use polyhydric alcohols, especially glycerin, tris(2
-hydroxyethyl) isocyanurate is preferred.

When reacting the polyhydric alcohol with the polyamide-imide resin composition, the polyhydric alcohol may be directly added to the phenolic solution of the polyamide-imide resin composition and reacted, or the polyhydric alcohol may be reacted with the polyamide-imide resin once taken out without using a solvent. Alternatively, the reaction may be carried out in an organic solvent.

However, in order to improve the efficiency of the reaction and to use the final resin solution, it is best to mix polyhydric alcohol in the final stage of the reaction of the polyamide-imide resin solution synthesized in a phenolic solvent and continue the reaction. preferable.

Since distilled water is generated when a polyhydric alcohol is blended into the polyamide-imide resin composition, the reaction temperature is preferably in the range of 180° C. to 250° C. at which distilled water can be completely distilled off.

The reaction time for this reaction varies depending on the degree of pressure reduction in the reaction system, but is usually in the range of 1 to 10-odd hours until no distilled water is observed. The reaction can be carried out at normal pressure, but in order to facilitate the generation of distilled water, it is also possible to reduce the pressure to the extent that the phenolic solvent is not distilled off.

Although this reaction can be carried out without a catalyst, it is also possible to use a catalyst commonly used in reactions using polyhydric alcohols.

Examples of such catalysts include - lead oxide, lead naphthenate,
Examples include metal salts of naphthenic acid such as zinc naphthenate, and organic titanium compounds such as tetrabutyl titanate, tetraprobyl titanate-1-, and triethanolamine titanate.

The blending ratio of polyhydric alcohol is particularly important, and is set in the range of 0.05 to 0.7 mol per 1 mol of tricarboxylic acid containing citric acid.

If it is less than 0.05 mol, the adhesion and flexibility when made into an insulated wire are insufficient, and the resin composition obtained by reacting a polyhydric carboxylic acid and/or its derivative with a polyhydric alcohol. The compatibility of is also reduced.

On the other hand, if the amount exceeds 0.7 mol, the adhesion and compatibility will be good, but the heat resistance, especially the heat softening temperature, of the resulting insulated wire will decrease, which is not preferable.・The resin solution of this polyimide-based resin composition has particularly excellent compatibility with a resin composition formed by reacting a polyhydric carboxylic acid and/or its derivative with a polyhydric alcohol, and this resin composition used after being denatured.

As the resin composition, a thermosetting initial composite generally known as a polyester resin coating in the field of insulation coatings can be used as is.

Examples of polycarboxylic acids and/or derivatives thereof as starting materials for the resin composition include terephthalic acid, isophthalic acid, 4.4'-benzophenone dicarboxylic acid, 4.4'
-diphenyldicarboxylic acid, naphthalene dicarboxylic acid, etc., and derivatives thereof such as lower alkyl esters and acid chlorides can also be used.

Further, as the polyhydric alcohol which is the starting material of the resin composition, one or more of the above-mentioned polyhydric alcohols that can be reacted with the polyamide-imide resin composition are used.

The reaction between the polyhydric carboxylic acid and/or its derivative and the polyhydric alcohol for producing the above-mentioned resin composition is carried out by a conventional method within the range where gelation does not occur in the absence of a solvent or in the presence of a phenolic solvent. Obtained by polycondensation reaction.

The ratio of the polyester resin composition blended into the polyamide-imide resin composition is 10 to 90% by weight based on the total amount of resin.
is suitable.

If it is less than 10% by weight, the effects of density and flexibility obtained by blending the polyester resin composition will not be sufficient, and if it exceeds 90% by weight, the heat shot resistance derived from the polyamide-imide resin will deteriorate. , abrasion resistance and heat resistance decrease.

The above-mentioned polyamide-imide resin has significantly increased compatibility with polyester resins, which have the same (terminal hydroxyl group) because the polyhydric alcohol added at the final stage of the reaction turns the terminal structure of the molecule into a hydroxyl group. .

Therefore, both resins are easily compatible even at room temperature, and a uniform resin composition can be obtained.

The resin solution of the polyamide-imide resin composition of the present invention is
It can be used as it is or with organic titanium compounds such as tetrabutyl titanate and tetrapropyl titanate, metal salts of naphthenic acid such as zinc naphthenate, Millionate MS-50 (
It can also be used as an insulating coating by blending a curing agent such as block isocyanate (manufactured by Nippon Polyurethane Co., Ltd.) or Desmodur CT Stable (block isocyanate, manufactured by Bayer Co., Ltd.).

The resin composition of the present invention exhibits extremely excellent solubility in phenolic solvents through the use of tricarboxylic acids including citric acid and/or its derivatives, and also has improved compatibility with other resins through modification with polyhydric alcohols. In addition to insulating paints, it can be applied not only to electrically insulating materials such as impregnated resins, laminates, films, and adhesives, but also to heat-resistant paints, fibers, and molded resins, making it extremely useful in practice. .

The present invention will be explained below with reference to Examples.

[Production Example 1 of Polyamide-imide Resin A] In a 3β-4 flask equipped with a thermometer, a stirrer, a cooling tube, and a nitrogen introduction tube, 19.217 (0.1 mol) of citric acid anhydride and 172.7 mm of trimellitic anhydride were added. 8 (1 (0,9 mol), diphenylmethane diisocyanate 250.30 (1,0
-E-le), 300 g of m-cresol, 100 g of solvent naphtha, and 1.0 g of boric acid were charged, and the temperature was raised to 200° C. over about 1 hour in a nitrogen stream.

Significant foaming was observed from around 10℃, and from 160 to 110℃
A small amount of distilled water was observed during this period.

Further, the reaction was carried out for 5 hours at the reflux temperature of cresol (200 to 210°C) while pumping out a small amount of cresol.

Then, tris(2-hydroxyethyl)isocyanurate 520 (0.2 mol) was added at 200°C to continue the reaction.

When tris(2-hydroxyethyl)isocyanurate was added, a dehydration reaction was observed, and water was distilled out along with a small amount of m-cresol.

After 2 hours, the viscosity of the contents increased and stirring became difficult, so m-cresol was added at 400°C to stop the reaction.

After returning to room temperature, 140 g of diphenylmethane diisocyanate blocked with l-cresol (containing 50% by weight of diphenylmethane diisocyanate) and m-cresol were added, thoroughly stirred, and adjusted to a non-volatile content of 24.3% by weight and a viscosity of 30 poise, resulting in a reddish brown color. A clear resin solution was obtained.

[Production Example 2 of Polyamide-imide Resin A] In a 3β four-eye flask similar to that used in Production Example 1, 1 part of anhydrous citric acid was added.
9.2 (] (00,1 mol, 1 to limellitic anhydride 172.80 (0,9 mol), diphenylmethane diisocyanate 252 (1 (1,01 mol), m-cresol 5001), '/ruben l -Naphtha 100
0 was charged and the temperature was raised to 200°C over about 1 hour in a nitrogen stream. Significant foaming was observed from around 70°C, and from 160°C to
The generation of distilled water was observed up to 180°C.

At 200° C., when the initial significant foaming was no longer observed, 4 g of boric acid was added, and the reaction was continued at this temperature for a total of 9 hours. The resin solution was clear during the reaction. Tris(2-hydroxyethyl)isocyanurate 78a (0,3
mol) was added and the reaction was continued for 5 hours while removing distilled water. Distilled water was no longer visible after about 4 hours. After cooling to room temperature, tetrabutyl titanate s, og and m-cresol were added and thoroughly stirred to give a non-volatile content of 37.8% by weight and a viscosity of 53.
A reddish-brown transparent resin solution was obtained by adjusting the poise.

[Production example 3 of polyamide-imide resin A] Anhydrous citric acid was placed in a 3J2 four-eye flask similar to that used in production example 1.
96. IQ (0.5 mol), trimellitic anhydride 96.1 (J (0.5 mol), diphenylmethane diisocyanate 260 (1 (1.04 mol)), m-cresol 300 (1), and 50 g of solvent naphtha were charged with nitrogen. The temperature was raised to 200°C in an air stream for about 1 hour. Significant foaming was observed from around 70°C, and the temperature was 160 to 180°C.
Further foaming and distilled water were observed as the temperature increased. m-
The reaction was continued for 8 hours at the reflux temperature of cresol (200-210°C). During the reaction, the viscosity of the resin solution increased,
And it was transparent.

Thereafter, glycerin 60 (1 (0.65 mol)) was added at 200°C, and the reaction was continued for 4 hours while removing distilled water.

Next, m-cresol 300 () was added and cooled to room temperature, and then m-cresol-blocked diphenylmethane diisocyanate (50 ffi fM, containing % diphenylmethane diisocyanate) 50 (] and m-resol were added and stirred thoroughly to remove the nonvolatile content. The resin solution was adjusted to 36.5% by weight and a viscosity of 70 poise to obtain a reddish-brown transparent resin solution.

[11 Preparation Example 1 of Polyester Resin B] Dimethyl terephthalate 970! I+, ethylene glycol 220Q
, Glycerin 230 (1, lead naphthenate 200) was charged into a 3β Mitsuro flask, and the temperature was gradually raised to 220°C over about 5 hours while allowing the methanol produced by the reaction to come out of the system. The exchange reaction was completed.

When methanol stopped coming out, the pressure was reduced at that temperature, and the reaction was continued for another 3 hours while allowing ethylene glycol to come out.

Next, 1650 (] of] mm-Frezi was added, and then 10 (l) of tetrabutyl titanate was added to reduce the non-volatile content (2
00℃ x 90 minutes, same below) 40% by weight, viscosity (30℃
, hereinafter the same) A 30 poise resin solution was obtained.

[Production Example 2 of Polyester Resin B] Dimethyl terephthalate 970Q, ethylene glycol 124 (1, tris (2- and droxyethyl) isocyanurate 780 (), lead naphthenate 20 ()) 3p
The temperature was gradually raised to 220° C. in about 6 hours while methanol produced by the reaction was taken out of the system, and the transesterification reaction was completed.

When methanol stopped coming out, the pressure was reduced at that temperature, and the reaction was continued for another 2 hours while allowing ethylene glycol to come out.

Then, a mixed solvent of l-resol/solvent naphtha=8/2, tooog, was added at once to stop the reaction.

Further, 10 g of tetrabutyl titanate was added and diluted with the above mixed solvent to obtain a resin solution with a nonvolatile content of 40% by weight and a viscosity of 52 poise.

Examples 1 to 6 The polyamide-imide resin solutions obtained in Production Examples A-1 to A-3 and the polyester resin solutions obtained in Production Examples B-1 and B-2 were mixed at room temperature in the proportions shown in Table 1. A homogeneous resin solution was obtained by mixing and stirring thoroughly.

In the table, 0 indicates the blending ratio (weight ratio) of the resin component.

(The following is a blank space) Table 1 The obtained resin solution was coated and baked on a 1.0 mmφ copper wire to produce an insulated wire. Table 2 shows the properties of the insulated wires obtained in Examples 1 to 6.

The comparative example in the table is an insulated wire manufactured using a commercially available polyester imide varnish (Isomid RH (trade name manufactured by Schenectady).
The wire speed was 12/min in a baking furnace with a furnace temperature of 400° C., and the characteristics of the insulated wire were measured in accordance with JI3 C3003.

(Margin below) 100- Table 2

Claims (5)

[Claims] (1) (A) A polyhydric alcohol is added to the reaction product obtained by reacting a tricarboxylic acid and/or its derivative containing at least 5 mol% of citric acid with an aromatic diisocyanate and/or its derivative in a phenolic solvent. (B) Polyhydric carboxylic acid and/or its derivative and polyhydric alcohol are added to a resin composition obtained by adding 0.05 to 0.7 mol per mol of tricarboxylic acid and further reacting in a phenolic solvent. A resin composition made by reacting (
A polyamide-imide resin composition, characterized in that it contains 10 to 90% by weight (based on the total resin weight after blending). (2) The polyamide-imide resin composition according to claim 1, wherein the tricarboxylic acid and/or its derivative contains at least 5 mol% of citric acid, and the remainder is an aromatic tricarboxylic acid and/or its derivative. (3) The polyamide-imide resin composition according to claim 1 or 2, wherein the aromatic tricarboxylic acid other than citric acid and/or its derivative is trimellitic anhydride. (4) Diisocyanate and/or its derivative,
The polyamide-imide resin composition according to any one of claims 1 to 3, which is an aromatic diisocyanate and/or a masked aromatic diisocyanate. (5) The aromatic diisocyanate and/or its derivative is 4,4'-diphenylmetal diisocyanate,
Claims 1 to 4 consist of one or more selected from 4,4'-diphenyl ether diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and derivatives in which these diisocyanates are masked with phenols. The polyamide-imide resin composition according to any one of the above.