JPS5880325A - Polyamide-imide resin composition and its production - Google Patents

Abstract

PURPOSE:The titled composition excellent in heat-softening resistance, markedly improved in organic solvent solubility and suitable for use in electrical insulating materials, heat-resistant paints, etc., prepared by reacting a tricaroxylic acid (derivative) containing citric acid with a diisocyanate (derivative). CONSTITUTION:A polyamide-imide resin composition prepared by reacting a tricarboxylic acid and/or its derivative (e.g., trimellitic anhydride) containing, for example, above 5mol% citric acid with a diisocyanate and/or its derivative (e.g., 4,4'-diphenylmethane diisocyanate) in, for example, a phenolic solvent. The use of citric acid makes it possible to obtain a resin composition which has excellent heat-softening resistance and, in addition, markedly improved solubility in organic solvents as compared with conventional aromatic polyamide-imide resins. This composition can be applied to the fields of heat-resistant paints, fibers and molding resins as well as electrical insulating materials such as impregnation resins, laminated sheets, films and adhesives in addition to insulating lacquers.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel polyamideimide resin composition and a method for producing the same.

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, alkybut resins, and epoxy resins. , polyesterimide resin, polyamideimide resin, polyimide resin, 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, which has 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, there are insulated wires that use polyesterimide resin paints that are soluble in relatively inexpensive phenolic solvents such as phenol, cresol, and xylenol at the expense of heat resistance, and
Double-covered wires, in which a polyesterimide resin paint is coated on the lower layer and a polyamide-imide resin paint is applied and baked on the upper layer, are now mainly used, but insulated wires using polyamide-imide resin paint have different characteristics. Due to the lack of balance, it has not been possible to satisfy the various requirements 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 X-organic solvents. Kosho 5
6-22330, Special Publication 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 to conduct intensive studies to develop a polyamide-imide resin composition with excellent solubility, and as a result, by using citric acid, which has been hardly considered as a material for heat-resistant resins, It has been found that a polyamide-imide resin composition can be obtained which has superior heat softening properties than aromatic polyamide-imide resins and also has significantly improved solubility in organic solvents.

The present invention has been made based on this knowledge, and is characterized by a polyamide-imide resin composition and a method for producing the same, characterized by reacting a tricarboxylic acid containing citric acid and/or a derivative thereof with a diisocyanate and/or a derivative thereof. This is what we are trying to provide.

The citric acid used in the present invention can be used with or without water of crystallization, but from the viewpoint of reaction efficiency, since the reaction with diisocyanate and/or its derivatives involves dehydration. Preference is given to using anhydrous citric acid without water of crystallization.

Tricarboxylic acids and/or derivatives thereof other than citric acid include, for example, aromatic tricarboxylic acids, aromatic tricarboxylic acid esters, aromatic tricarboxylic acid anhydrides, and the like represented by formula (1) or @, used alone or in mixtures.

CO R, (COOR,), R,0OC-R, (.o
)0(I)@ Generally, trimellitic anhydride is preferred from the viewpoints of heat resistance, high reactivity, economic efficiency, etc.

In addition, in order to increase the imide bond ratio and improve heat resistance, a part of the tricarboxylic acid was replaced with pyromellitic anhydride, 3.3'
, 4.4'-benzophenonetetracarboxylic anhydride,
It is also possible to substitute with a tetracarboxylic acid such as butanetetracarboxylic acid, or a derivative thereof.

On the other hand, if you want to increase the number of amide bonds from the standpoint of balancing the properties of a multi-component system, use terephthalic acid, isophthalic acid, oxalic acid, malonic acid, succinic acid, curtaric acid, adipic acid,
Aromatic or aliphatic dibasic acids such as pimelic acid, speric acid, yleic acid, etc. can also be used as part of the tricarboxylic acid.

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

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

As the ratio of citric acid increases, the solubility in organic solvents increases, so the ratio of citric acid can be arbitrarily changed within the above range depending on the form in which the resin composition of the present invention is used.

As the diisocyanate and/or its derivative used in the present invention, any aliphatic, alicyclic, or aromatic diisocyanate and/or its derivative can be used. Suitable diisocyanates include ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, heptamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, trimethylhexamethylene diisocyanate, morpholine diisocyanate. , cyclohexane diisocyanate, 3,9-bis(3-isopropyl cyanate), 2,4°8.10. Tetraoxaspiro [5
・5] Aliphatic and alicyclic diisocyanates such as Kundecane, 4゜4'-diphenylmethane diisocyanate,
4, 4'-diphenyl ether diisocyanate), 4
．． 4'-Schiff, nylpropane diisocyanate, 4
, 4'-diphenylsulfone diisocyanate), 3.3
'-Diphenylsulfone diisocyanate, 4°, 4'
-Diphenyl sulfite 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-)
There are aromatic diisocyanates such as lylene diisocyanate, m-xylylene diisocyanate, and p-xylylene diisocyanate, and these can be used alone or in combination.

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

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

Among the isocyanate compounds, 4.4'-diphenylmethane diisocyanate, 2.4-)lylene diisocyanate,
2.6-) lylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, 4
, 4'-diphenyl ether diisocyanate and the like are particularly preferably used alone or in combination.

The reaction temperature and reaction time for the reaction of tricarboxylic acids and/or their derivatives, including citric acid, with diisocyanates and/or their derivatives vary depending on the starting materials and the type of reaction, solution reaction or solvent-free reaction, but in general, Reaction temperature is 60 to 350℃, reaction time is from several hours to several dozen
done in time.

In the case of a solution reaction, the decarboxylation reaction between carboxylic acid or its derivative and diisocyanate starts at around 70°C, although it is affected by many factors such as the solvent used, the solid content at the time of charging the starting materials, and the presence or absence of a catalyst. Also, in consideration of the boiling point range of the solvent commonly used in this reaction, the preferred reaction temperature range is 70 to 250°C.

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

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

However, solution reaction is more preferable 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, since the resin composition of the present invention has excellent solubility, many organic solvents can be used, but those that react with the starting materials are not preferred.

Suitable solvents for the present invention include phenol, -trisol, m-cresol, p-cresol, various xylenolic acids, various chlorophenols, nitrobenzene, N-methyl-2-pyrrolidone, N, N' -Dimethylformamide There are dimethylacetamide, hexamethylphosphoramide, dimethylsulfoxide, etc., and solvents that can be used in combination with these include benzene, toluene, xylene, and high-boiling aromatic hydrocarbons (for example, Maruzen Sekiyu Swasol too , Cresol 1500, Nippon Oil's Nisseki Hysol 100.8 koku)\Isol 15
0, etc.), ethylene glycol monomethyl 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 aromatic hydrocarbon solvent from the viewpoint of stability, film-forming properties, economic efficiency, etc. of the resulting resin solution.

There is no particular restriction on the solid content concentration during the reaction, but if it is less than 35%, the reaction will take a long time, side reactions will easily occur, and a highly polymerized resin composition will not be obtained, so it should be 35% or more. More preferred.

The reaction of the present invention can be accelerated by catalysts commonly used for reactions of isocyanates.

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

A suitable amount to be used is o.oi to 5% based on the solid content at the time of preparation, and the method of addition is not particularly limited.

The molar ratio of tricarboxylic acid, including citric acid, and/or its derivative to diisocyanate and/or its derivative is preferably approximately 1:1.

However, an excess of about 10 mol % or less of either one is within an acceptable range.

The tricarboxylic acid and/or its derivative including citric acid and the diisocyanate and/or its derivative may be charged at the same time before starting the reaction, 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 and the degree of wetting of reaction water, as well as the viscosity of the solution.

The resin composition of the present invention can also be blended with other resins if necessary.

Also other functional compounds such as polyols, polyamines,
A modified polyamideimide resin composition can be produced by adding polycarboxylic acid and further reacting.

The resin composition of the present invention exhibits extremely excellent solubility even in phenolic solvents by using tricarboxylic acids including citric acid and/or its derivatives, and is an aromatic polyamide that is soluble only in conventional organic polar solvents. Because it has better heat resistance than imide resin, it can be applied not only to insulation paints but also to electrical insulation materials such as impregnated resins, laminates, films, and adhesives, as well as heat-resistant paints, fibers, and molded resins. Above all, it is extremely useful.

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

Example 1 Citric anhydride 96.1 N (0.5 mol) and trimellitic anhydride 96.19 N (0.5 mol) were placed in a 314 Tulo flask equipped with a temperature needle, stirrer, cooling tube, and nitrogen inlet tube.
, 250.3 g of diphenylmethane diisocyanate (
1,0 mol), m-cresol 400'9,
The temperature was raised to 20011:: in a nitrogen stream over about 1 hour.

Significant foaming was observed from around 70°C, and further foaming and wetting water were observed from 160 to 180°C.

2 at the reflux temperature of m-cresol (200-210 °C)
The reaction continued for 00 hours.

During the reaction, the solution showed an increase in viscosity and was completely transparent.

Next, add cresol 40011 and stir thoroughly to obtain a nonvolatile content (200 t:: X 1.5 H) of 30.1%.
A reddish-brown transparent resin solution with a viscosity (250° C.) of 62 voids was obtained.

The obtained resin solution was heated at 200°C on a copper plate of O, lu + thickness.
The coating film obtained by baking for 20 minutes at 250 °C and 3θ minutes at 250 °C has sufficient flexibility, and the infrared absorption of the coating film is
In each case, absorption of amide group was observed at cm-'.

In addition, the obtained resin solution was added to 1. Table 1 shows the properties of the insulated wire obtained by coating and baking the copper wire -F in OM.

Example 2 In a 314 Solo flask equipped with a thermometer, stirrer, cooling tube, and nitrogen inlet tube, 153.7 g (0.8 mol) of citric acid anhydride and 38.4 Ii (0.2 mol) of trimellitic anhydride were added. ), diphenylmethane diisocyanate 250.3g (
1.0 mol), m-cresol 300 J9,
The temperature was raised to 200°C over about 2 hours in a nitrogen stream.

Significant foaming occurred from around 70°C, and wetting water was observed at the same time as foaming from 160 to 200°C.

The reaction was continued at 210° C. for 18 hours while distilling off the wetting water.

The solution was transparent during the reaction, and the viscosity increased with time.

Next, m-cresol soog, solvent naphtha (
Cresol 260.9 (manufactured by Maruzen Sekiyu Co., Ltd., $1000) was added and thoroughly stirred to obtain a reddish-brown transparent resin solution with a nonvolatile content of 20.0% and a viscosity of 45 poise (25°C).

The resulting resin solution was baked on a 0.1 m thick copper plate at 200°C for 20 minutes and at 250°C for 30 minutes.The resulting coating film had sufficient flexibility and the infrared absorption spectrum of the coating film has an imide group at 1780 tx-” and 1650 (In
-' absorption of amide group was observed in each case.

Table 1 shows the properties of an insulated wire obtained by coating and baking the resin solution on a 1.0 mm copper wire.

Example 3 Anhydrous citric acid 19.29 (0.1 mol) was placed in a 3/4 flask equipped with a thermometer, stirrer, cooling tube, and nitrogen introduction tube.
trimellitic anhydride 172.8, SF (0.9 mol), diphenylmethane diisocyanate) 250.3
II (x, 0-r-l), m-ri L/sol 400.
9 was prepared and 200 t was prepared in a nitrogen stream for about 1 hour:
: The temperature was raised to .

Significant foaming was observed from around 70°C, and slight wetting water was observed from 160 to 170°C.

The reaction was continued for 22 hours while wetting out a small amount of cresol at the reflux temperature of cresol (200-210°C).

The reacted resin solution was clear.

The total amount of cresol leached out was 100 g.

Next, 800 N of m-cresol was added and thoroughly stirred to obtain a reddish brown transparent resin solution with a nonvolatile content (200°C x 1.5 Tl) of 23.3% and a viscosity (25°C) of 55 voids.

The obtained resin solution was placed on a copper plate with a thickness of 0.1 tel (:l
The coating film obtained by baking at -200℃ for 20 minutes and 250℃ for 30 minutes has sufficient flexibility, and its infrared absorption spectrum is 1780c, IL-1 niimide group, and 1650f.
Absorption of i-' niamide group was observed in each case.

The infrared chart is shown in Fig. 1C-2.

Furthermore, Table 1 shows the properties of an insulated wire obtained by coating and baking the obtained resin solution onto a copper wire in QW.

Example 4 Anhydrous citric acid 192.1.9 (1.0 mol), diphenylmethane diiso Vane) 250.311 were placed in a 3/4 flask equipped with a temperature control, stirrer, cooling tube, and nitrogen inlet tube.
(1.0 mol) and 500 g of m-cresol were charged and the temperature was raised to 200°C over about 1 hour in a nitrogen stream.

Significant foaming occurs from 70°C, then from 160 to 200°C.
A lot of running water was seen.

When the reaction was continued at 200° C. for 10 hours, the viscosity of the entire product increased and it became gel-like.

At this point, 800 g of cresol was added and stirred thoroughly to reduce the non-volatile content (200°C x 1.5)I) to 19.2%.
A reddish-brown transparent resin solution with a viscosity of 31 poise (25° C.) was obtained.

The resulting resin solution was placed on a 0.111I thick copper plate for 200 minutes.
The coating film obtained by baking for 20 minutes at ℃ and -30 minutes at 250℃ has sufficient flexibility, and its infrared absorption spectrum includes an imide group at 1780 cm and an imide group at 1640 to 1680 cm.
Broad absorption of amide groups was observed in each case.

The infrared chart is shown in FIG.

In addition, the obtained resin solution was added to 1. Table 1 shows the properties of the insulated wire obtained by coating and baking the insulated wire on the copper wire in Ol.

Example 5 Citric anhydride 11.511 (0.06 mol) and trimellitic anhydride 180.6 Ii (0.9
4 mol), diphenylmethane diisocyanate 87.1
g (0.5 mol), tolylene diisocyanate 8f,
ll1 (0.5 mol) and m-cresol 400I were 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 a slight amount of distilled water was observed from 160 to 170°C.

The reaction was continued at 210°C for 10 hours.

Next, 550 g of m-cresol was added and thoroughly stirred to obtain a reddish-brown transparent resin solution with a nonvolatile content (200°C x 1.51'I) of 25.0% and a viscosity (25°C) of 75 poise.

The obtained resin solution was heated at 200℃ for 2 hours on a copper plate with a thickness of 1m.
The coating film obtained by baking at 250°C for 30 minutes has sufficient flexibility, and the infrared absorption spectrum of the coating film is 17.
80 cm-'l: imide group, 1650 ex-"
Absorption of amide groups was observed in each case.

Table 1 shows the properties of an insulated wire obtained by coating and baking the resin solution on a 1.01111 copper wire.

Example 6 38.4 g (0.2 mol) of anhydrous citric acid was placed in a 3/4 flask equipped with a thermometer, stirrer, cooling tube, and nitrogen inlet tube.
, trimellitic anhydride 153.7 g (0.8 mol), diphenylmethane diisocyanate 262.8 g (
1.05 mol) and m-cresol 40011 were 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 distilled water was observed from 160 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 7 hours.

The reacted resin solution was clear.

Next, Cresol 350I Purbento Naphtha (Maruzen Sekiyu Swasol + 1000) 33017 was added and thoroughly stirred to reduce the non-volatile content (200°C x 1.5 H) 2
A reddish-brown transparent resin solution with a viscosity of 5.2% and a viscosity (25° C.) of 82 poise was obtained.

The resulting resin solution was baked on a 0.1M thick copper plate at 200°C for 2θ minutes and at 250°C for 30 minutes.The resulting coating film had sufficient flexibility and had a good infrared absorption spectrum. is 1
Imide group at 780 cx-', 1650 ex-"
Absorption of amide groups was observed in each case.

Table 1 shows the properties of an insulated wire obtained by coating and baking the resin solution on a 1.0 mm copper wire.

Example 7 Diphenylmethane diisocyanate 250 was added to a 3/4 tube flask equipped with a temperature needle, stirrer, cooling tube, and nitrogen inlet tube.
．． 3 N (1.0 mol), m-cresol 400 g
The temperature was gradually raised to 200° C. for 30 minutes.

When a portion of the contents was taken out and its infrared absorption spectrum was measured, no absorption of the incyanate group at 2260 cm was observed, confirming that the diisocyanate was masked by m-cresol.

Lower the internal temperature to 70℃ and anhydrous citric acid 57.6.9 (0,
3 mol), trimellitic anhydride 134.59 (0,
7 mol) and heated to 200℃ for about 1 hour in a nitrogen stream.
The temperature rose to .

Foaming was gradually observed from around 130°C, and distilled water was observed at the same time as foaming from around 150°C.

The reaction continued at 210°C for 12 hours.

Next, m-cresol 450g Solvent naphtha (Maruzen Sekiyu Swasol #1000) 200,! 9
was added, stirred thoroughly, and the non-volatile matter (200℃ x 1.5H
) A reddish-brown transparent resin solution with a viscosity (2.5° C.) of 52 voids and a viscosity of 24.8% was obtained.

The resulting resin solution was baked on a 0.1-inch thick copper plate at 200°C for 20 minutes and at 250°C for 30 minutes.The resulting coating film had sufficient flexibility, and the infrared absorption spectrum of the coating film 1 for
Imide group absorption was observed at 780 am-'' and amide group absorption was observed at 1650 cm-''.

Table 1 shows the properties of an insulated wire obtained by coating and baking the resin solution on a 1.0-mesh copper wire.

Example 8 Tetrabuterdetanane) 5II was gradually added to the resin solution obtained in Example 3 (1000.9 g) at room temperature and thoroughly stirred.

The properties of the insulated wire obtained by coating and baking this resin solution on a 1.0 mm copper wire are shown in Table 1.

Furthermore, the TG of the obtained insulated wire coating was heated at a heating rate of 10,
The results of measurement in an atmosphere of 100 m2 of air are shown in FIG. In the figure, 1 indicates the wire coating of Example 1, and 2 indicates the wire coating produced using a commercially available polyamide-imide varnish.

The comparative example was a commercially available amide varnish containing N-methyl-2-pyrrolidone as the main solvent (Hitachi Chemical HI-400).
) was used.

Example 9 Citric anhydride 38.417 (0.2 mol), trimellitic anhydride 153.777 (0.8 mol), and diphenylmethane were placed in a 314 Tulo flask equipped with a temperature needle, stirrer, cooling tube, and nitrogen inlet tube. Diisocyanate 200.21
(o, s mol), diphenyl ether diisocyanate 25.277 (0.1 mol), xylylene diisocyanate 18.8 fl (0.1 mol), and m-cresol 400 g were prepared and heated in a nitrogen stream for about 1 hour.
The temperature was raised to 0°C.

Significant foaming was observed from around 70°C and distilled water was observed from 160 to 180°C.

The reaction was continued at 210°C for 15 hours, and then m-cresol 680 fi and flubento naphtha (Maruzen Sekiyu Swazol #1000) 3001i were added and thoroughly stirred to give a non-volatile content (200°C x 1.5 H) of 20.0%. ,
A reddish-brown transparent resin solution with a viscosity (25° C.) of 45 poise was obtained.

The resulting resin solution was baked on a 0.1-thick copper plate at 200°C for 20 minutes and at 250°C for 30 minutes.The resulting coating film had sufficient flexibility and the infrared absorption spectrum of the coating film 1 for
Imide group at 780 ffi”-”, 1650 cm
-” absorption of amide groups was observed in each case.

In addition, the obtained resin solution was added to 1. Table 1 shows the properties of the insulated wire obtained by coating and baking on the copper wire shown in Figure O.

Example 10 96.1 g (0.5 mol) of citric acid anhydride and 96.111 g (0.5 mol) of trimellitic anhydride were placed in a 3I4 Turow flask equipped with a temperature needle, stirrer, cooling tube, and nitrogen inlet tube.
, diphenylmethane diisocyanate 250.377
(1.0 mol), N-methyl-2-lerolidone 400
g was charged and the temperature was raised to 200° C. over about 1 hour in a nitrogen stream.

Foaming was observed from around 70°C.

The reaction was continued for 12 hours while distilling off a small amount of N-methyl-2-pyrrolidone at the reflux temperature of N-methyl-2-pyrrolidone.

Next, 450 I of N-methyl-2-pyrrolidone was added and thoroughly stirred to obtain a solution containing 29.5% of non-volatile content (200°C x 1.5H).
A reddish-brown transparent resin solution with a viscosity (25° C.) of 60 voids was obtained.

The resulting resin solution was baked on a 0.1M thick copper plate at 200°C for 20 minutes and at 250°C for 30 minutes.The resulting coating film had sufficient flexibility, and the infrared absorption spectrum of the coating film is 1
Imide group absorption was observed at 780α-1 and amide group absorption was observed at 1650 tx-''.

Comparative example 31t4 with temperature needle, stirrer, cooling tube, and nitrogen introduction tube
Trimellitic anhydride 192.177 in Tulo flask
(1,0 mol), diphenylmethane diisocyanate 2
50.3.9 (1.0 mol), m-cresol 400
g was charged and the temperature was raised to 200° C. over about 1 hour in a nitrogen stream.

Foaming was observed from around 70°C, but no seeping water was seen from around 160°C, and the reflux temperature of cresol (200-21
(0°C), the solution became opaque and did not become clear even after 10 hours of reaction.

Margin below

[Brief explanation of drawings]

Figure 1~! Figure J2 is an infrared chart of the polyamideimide resin of the example of the present invention, and Figure 3 is the 70 curve of the example of the present invention. Representative Patent Attorney Sasa Suyama - Same as above Yama 1) Nobuo Akira

Claims (1)

[Claims] 1. A polyamide-imide resin composition characterized by reacting a tricarboxylic acid containing citric acid and/or a derivative thereof with a diisocyanate and/or a derivative thereof. 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. 5. The polyamide-imide resin composition according to claim 1, wherein the tricarboxylic acid is citric acid alone. 4. The polyamide-imide resin composition according to claim 1 or 2, wherein the aromatic tricarboxylic acid and/or its derivative is trimellitic anhydride. 5. The polyamide-imide resin composition according to any one of claims 1 to 4, wherein the diisocyanate and/or its derivative is an aromatic diisocyanate and/or a masked aromatic diisocyanate. 6. Aromatic diisocyanate and/or its derivative is 4,4'-diphenylmethane diisocyanate, 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 items. 7. A method for producing a polyamide-imide resin composition, which comprises reacting a tricarboxylic acid and/or its derivative containing at least 5 mol % or more of citric acid with an aromatic diisocyanate and/or its derivative in a phenolic solvent. .