JPH11228693A - Polyimide resin solution and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject solution capable of exhibiting excellent moldability and processability, readily producing a formed material such as a film having excellent heat resistance, insulating properties and sticking processability, by dissolving a specific amount or more of a polyimide resin in a polar organic solvent. SOLUTION: A polyimide resin e.g. a polyimide resin containing a repeating unit of formula I [R1 is phenylene, ethylene or a group of formula II; R2 is a difunctional organic group such as a group of formula III ((n) is l-10)], capable of being made into a film, having <=200 deg.C glass transition temperature and <=1% water absorption ratio} in an amount of 1-10% is dissolved in a polar organic solvent (e.g. N,N-dimethylformamide). The solution is obtained, for example, by reacting a tetracarboxylic acid dianhydride with an aromatic diamine in a polar solvent to give a solution of a polyamic acid having 50,000-250,000 weight-average molecular weight, mixing the solution with a carboxylic acid anhydride containing acetic anhydride and a β-picoline-containing amine and subjecting the mixture to ring formation reaction through dehydration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a polyimide resin solution. More specifically, the present invention relates to a polyimide resin solution in which a polyimide resin is dissolved in a polar organic solvent by 10% or more, and a method for producing the same. More specifically, polyimide film,
Having a film formability and a glass transition temperature of 200 ° C., which can be suitably used when forming a heat-resistant insulating film or the like.
Below, 10% of polyimide resin with water absorption of 1.0% or less
The above relates to the dissolved polyimide resin polar organic solvent solution.

[0002]

2. Description of the Related Art Hitherto, polyimide resins have been known as organic polymer materials having excellent heat resistance, insulation properties and low dielectric properties, as well as excellent mechanical properties, radiation resistance and low temperature resistance.・ In the electronics and aerospace industries,
It is used as a heat-resistant coating material or an insulating film material. Especially in the electronics and electrical industries, it is used as an electrically insulating film, passivation film, coating material, resist material, liquid crystal alignment film material, and also as a material for printed circuit boards and molding materials. It is expected.

[0003] In recent years, in the electric and electronic industries, electronic equipment has been enhanced in function, performance, and miniaturization, and accordingly, electronic components constituting the electronic equipment have become thinner, smaller, and lighter. It has been demanded. For this reason, a thinner film and a smaller area have been strongly required for a polyimide material used for an electronic component. Until now, when using polyimide as an electronic component material, a film made of polyimide resin was processed into a desired shape by punching, slitting, etching, laminating the film, etc. In order to respond to the demand for a smaller area, a method of obtaining a desired polyimide film by drying and curing a solution containing a polyimide resin, which is applied or adhered to a metal substrate or a film substrate, or the like, is used. It has become

[0004]

However, polyimide resins are generally hardly soluble or insoluble in organic solvents.
Even in the case of showing solubility, since it is about 1 to 5% by weight, it was difficult to obtain a high-concentration polyimide-based resin solution. When the solubility is 5% by weight or less, a solution containing a polyimide-based resin is applied or adhered to a metal substrate or a film substrate, and dried and cured to form a polyimide film. In order to obtain a sufficient thickness to fulfill the above function, coating and drying must be repeated a plurality of times.

Therefore, a solution of polyamic acid, which is a precursor of polyimide, is used as a polyimide resin solution. In this case, the polyamic acid solution is applied or adhered to a base material such as a metal, and then dried and imidized by heating to form a polyimide film.However, imidization requires heating at a high temperature for a long time. In addition, there is a problem in terms of processability and reliability such that water generated during imidization corrodes metal.

Further, the polyimide resin has a high water absorption rate, and there is a problem that package cracks occur due to moisture absorption of the polyimide resin in a sealing step in manufacturing a semiconductor device.

[0007] In addition, when a polyimide resin is used as a material for bonding a substrate and a semiconductor chip or the like, that is, as an adhesive for a semiconductor, it is also desired to have a heat-sealing property.

Furthermore, when used as an adhesive for semiconductors, the polyimide resin must have good film formability. When forming a polyimide film by drying the polyimide resin solution and poor film formability,
Cracks occur in the film itself, or when attaching a substrate and a semiconductor chip via a polyimide film, the polyimide film,
That is, the bonding process, in which cracks occur in the adhesive layer, and the bonding reliability are inferior.

[0009] In view of such circumstances, the present inventors have
It is an object of the present invention to solve the above conventional problems and to provide a polar organic solvent solution of a polyimide resin having excellent heat resistance, excellent insulation properties, and a sufficiently low glass transition temperature and low water absorption so as to enable bonding. After careful examination,
This has led to the present invention.

[0010]

SUMMARY OF THE INVENTION The gist of the polyimide resin solution according to the present invention is that a polar organic solvent contains 10%.
% Or more of the polyimide resin is dissolved.

Another feature of the polyimide resin solution according to the present invention is that the polyimide resin has the general formula (1)

[0012]

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(Wherein, R ₁ is

[0014]

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At least one selected from the organic groups represented by and R ₂ represents a divalent organic group. ), Having a glass transition temperature of 200
C. or less and water absorption of 1.0% or less, which means that 10% or more is dissolved in a polar organic solvent.

In the general formula (1), R ₂ is

[0017]

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(Wherein, n represents 1 to 10).

The gist of the method for producing a polyimide resin solution is that, in the method for producing a polyimide resin solution according to any one of claims 1 to 3, the polyimide resin comprises tetracarboxylic dianhydrides. A polyamic acid obtained by reacting an aromatic diamine with a polar organic solvent is subjected to dehydration and ring closure in a solution.

It is another object of the present invention to adjust the weight average molecular weight of the polyamic acid, which is a precursor of the polyimide resin, to 50,000 to 250,000.

The polyamic acid solution further comprises at least one carboxylic anhydride containing acetic anhydride, and β-
After mixing with at least one kind of amines including picoline, it is intended to carry out dehydration ring closure.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a polyimide resin solution according to the present invention will be described below.

The polyimide resin solution according to the present invention has the general formula (A)

[0024]

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[0025] (wherein, R R ₁ in the general formula (1) ₁
And the same divalent organic group as described above. And a tetracarboxylic dianhydride containing an ester group represented by the general formula (B):

[0026]

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[0027] (wherein, R ₂ is R ₂ in the general formula (1)
And the same divalent organic group as described above. ) Can be obtained as a raw material.

In particular, in the general formula (A), R ₁ is

[0029]

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The tetracarboxylic dianhydride represented by the following formula is preferred.

Tetracarboxylic acid represented by the general formula (A)
The most representative examples of dianhydrides are 2,2^'-Screw (4-
(Hydroxyphenyl) propanedibenzoate-3,3^'
4,4 ^'-Ethylene glycol benzoate tetracarbo
Acid dianhydride (hereinafter abbreviated as ESDA), 3,3^'4,4
^'-Ethylene glycol benzoate tetracarboxylic acid
Dianhydride (hereinafter abbreviated as TMEG), 1,4-hydroquino
Ndibenzoate-3,3 ^' 4,4^'-Tetracarboxylic acid
Water (hereinafter abbreviated as TMHQ) and the like.
Alternatively, two or more kinds can be used in combination. And other
One or two or more tetracarboxylic dianhydrides
It can be used in combination. Other tetracarboxylic acids
As the dianhydride, 4,4^'-Oxydiphthalic dianhydride
(Hereinafter abbreviated as ODPA), 3,3 ', 4,4'-biphenylte
Tracarboxylic dianhydride (hereinafter abbreviated as BPDA), etc.
Is mentioned.

Here, the general formula (A)

[0033]

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The tetracarboxylic dianhydride represented by
A method of reacting trimellitic anhydride monochloride and dihydric phenol at room temperature or lower, or a method of reacting trimellitic anhydride and dimethyl ester of dihydric phenol with 200
It can be synthesized by a method of reacting at a high temperature of 高温 300 ° C.

The dihydric phenol used as the raw material includes hydroquinone, ethylene glycol, resorcinol, 2-bis- (4-hydroxyphenyl) propane, and the like.

Next, the compound represented by the general formula (B) 11

[0037]

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As the aromatic diamine represented by the formula:
^' -Diaminodiphenyl ether (hereinafter referred to as ODA), 2,2-bis (4- (4-aminophenoxy) phenyl) propane (hereinafter referred to as BAPP), 2,2-bis (
4-aminophenoxy) ethane, 1,2-bis (4-aminophenoxy) diethyl ether, 1,2-bis (2- (4- (4-aminophenoxy) ethoxy) ethane, and the like. 1,2-Bis (4-aminophenoxyethoxy) ethane can be preferably used as an aromatic diamine which gives a polyimide having a well-balanced property such as low water absorption.

The polyimide resin represented by the general formula (1) produced using the above raw materials is a polar organic solvent, for example, N, N-dimethylformamide (hereinafter, referred to as DMF), N, N-dimethyl. Acetamide (hereinafter, DMAc
That. ), N-methyl-2-pyrrolidone (hereinafter NM)
Abbreviated as P. ) Or other amide polar organic solvent
5% can be dissolved.

The polyimide resin used in the polyimide resin solution according to the present invention is preferably a resin represented by the general formula (2):
Formula 12

[0041]

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It is preferable to contain the structure represented by the following formula. This polyimide resin has the general formula (A):

[0043]

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(Wherein R ₁ is the same as R ₁ in the general formula (1))
_{Shows the} same organic group as 1. And a tetracarboxylic dianhydride represented by the general formula (C):

[0045]

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(Wherein, n represents 1 to 10), and can be obtained by a polymerization reaction using an aromatic diamine represented by the following formula:

The aromatic diamine represented by the general formula (C) can be used alone or in a mixture of two or more kinds corresponding to any one of 1 to 10 in the formula. Further, other diamines may be used alone or in combination of two or more. Other diamines, ODA, 4,4 ^'- diamino-benzanilide, BAPP, 2,2-bis [4- (3-aminophenoxy) phenyl] propane (hereinafter, BAPPM
Abbreviated. ) And 1,3-bis (3-aminophenoxy) benzene (hereinafter abbreviated as APB).

The polyimide resin represented by the general formula (2) can be dissolved in the polar organic solvent by about 10 to 20%. Conventional polyimide resins are difficult to dissolve in such a polar organic solvent, and the present invention provides a polyimide resin solution in which the polyimide resin is dissolved in an organic polar solvent by 10% or more.

Next, a method for producing a polyimide resin solution according to the present invention will be specifically described.

The polymerization method for obtaining the polyimide resin used in the present invention includes a two-step synthesis method in which a polyamic acid is synthesized and isolated in a polar solvent and then imidized to obtain a polyimide resin. Thus, a one-step synthesis method for obtaining the polyimide polymer represented by the general formula (1) by completing the synthesis and imidation of the polyamic acid can be used.

The polyamic acid solution produced by the above method preferably has an average molecular weight adjusted to 50,000 to 250,000, more preferably 100,000 to 200,000. When the weight average molecular weight is smaller than 50,000, the film formability of the obtained polyimide resin is inferior. On the other hand, when it is larger than 250,000, the obtained polyimide resin is difficult to be dissolved in the polar organic solvent, that is, the solubility is poor.

First, the one-step synthesis method will be described. Using an acid dianhydride represented by the general formula (A) and an aromatic diamine represented by the general formula (B) or (C) in a polar solvent at 0 to 100 ° C. After reacting for several tens of minutes to several hours, the tetracarboxylic dianhydride represented by the general formula (A) and the aromatic diamine represented by the general formula (B) are converted into a compound represented by the general formula (D).

[0053]

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The polyamic acid represented by the general formula (E) is converted from the tetracarboxylic dianhydride represented by the general formula (A) and the aromatic diamine represented by the general formula (C). 16

[0055]

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After synthesizing the polyamic acid represented by the formula, imidization is performed.

The polyamic acid having a weight-average molecular weight is preferably such that the mixing ratio of the acid dianhydride and the diamine is preferably 0.8 to 1.2 with respect to 1 equivalent of the tetracarboxylic dianhydride. Equivalent, preferably 0.95-
It is obtained by using 1.05 equivalents. A polyamic acid can be obtained by reacting the acid dianhydride and the diamine, for example, in a polar solvent such as N, N-dimethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidone. . The reaction time varies depending on the components of the polyamic acid and the like, but the reaction can be carried out at a temperature of 0 to 100 ° C for tens of minutes to several hours.

According to the above method, the obtained polyamic acid is imidized to obtain a desired polyimide resin which can be used in the present invention.

The imidization is carried out by (1) a method in which the reaction is carried out by heating at 50 to 200 ° C. for several tens of minutes to several hours, and (2) a carboxylic acid such as acetic anhydride at 50 to 180 ° C. There is a method of promoting imidization by adding 2 to 5 equivalents of anhydrides and 1 to 2 equivalents of amines such as β-picoline.

Among the above methods, the method (2) is preferable as a method for obtaining a polyimide resin having excellent film moldability. In general, in the method (1), since the treatment is performed at a higher temperature and for a longer time than in the method (2), the decomposition reaction of the polyamic acid, which is a side reaction of the imidation reaction, is compared with the method (2). This is because the progress proceeds more, and a polyimide resin having a relatively large amount of low molecular weight components and inferior in film moldability is generated.

When a polyamic acid is dehydrated and ring-closed in a solution to obtain a polyimide resin, at least one carboxylic anhydride containing acetic anhydride and at least one amine containing β-picoline are mixed in the polyamic solution. After that, it is preferable to carry out dehydration ring closure.

Next, the two-stage synthesis method will be described. The polyamic acid having the weight-average molecular weight is a dicarboxylic acid in an amount of from 0.8 to 1 equivalent of tetracarboxylic dianhydride.
1.2 equivalents, preferably 0.95 to 1.05 equivalents, used in a polar solvent such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, and After producing a polyamic acid by reacting at a temperature in the range of 0 ° C, preferably 0 to 60 ° C, the polyamic acid is isolated from the reaction solution. By a conventionally used dehydration cyclization method of the isolated polyamic acid,
The polyimide resin solution used in the present invention represented by the general formula (1) or (2) according to the present invention can be produced.

To obtain a high molecular weight polyimide polymer,
It is preferable to mix the tetracarboxylic dianhydride and the diamine in the above range, and outside of this range, only low molecular weight compounds tend to be obtained.

As the dehydration cyclization method, (1) a method in which a polymer is isolated and then cyclized by heating at 150 to 350 ° C.
(2) After isolation, in a solution state in which a polyamic acid is dissolved in an organic solvent, 80 to 400 ° C., preferably 100 ° C.
A method of cyclizing by heating at ~ 250 ° C; (3) when isolating and dehydrating and ring-closing a polyamic acid in a solution state in which the polyamic acid is dissolved in an organic solvent to obtain a polyimide resin, the polyamic acid solution contains carboxylic anhydride or the like; There is a method of cyclizing with a chemical dehydrating agent or the like.

In the method (2), benzene,
It is preferable to use a solvent azeotropic with water, such as toluene or xylene.

In the above method (3), the cyclization reaction with the carboxylic acid anhydride such as acetic anhydride, propionic anhydride, benzoic anhydride and phthalic anhydride is promoted in the polyamic acid solution. As a substance, it is preferable to carry out dehydration ring closure after mixing amines.

Examples of the amines include triethylamine, tripropylamine, quinoline, isoquinoline, pyridine, β-picoline, etc., and preferably β-picoline as a main component. These carboxylic dianhydrides and amines may be used alone or in combination of two or more.

In this case, it is preferred that at least one carboxylic anhydride containing acetic anhydride and at least one amine containing β-picoline be mixed and then dehydrated and closed.

Acetic anhydride has a relatively low boiling point among the carboxylic anhydrides described above, and is preferred because it is easy to dry when the polyimide resin is isolated from a solution to obtain the polyimide resin as a powder. Also, β-picoline promotes imidization more than other amines and has a well-balanced amine having a relatively low boiling point when producing a polyimide resin.

As a method for obtaining the polyimide resin used in the present invention from the polyamic acid produced by the above-mentioned method, for example, the reaction solution obtained as described above is prepared by mixing the reaction solution obtained with the above-mentioned polar solvent such as lower alcohol, water or the like. In addition, there is a method in which a solution which is a poor solvent with respect to the resin is poured into a large excess to obtain a precipitate, which is filtered, dried and pulverized to obtain a powder.

The form of the polyimide resin used in the present invention is as follows:
From the viewpoint of storage stability, it is preferably in the form of a powder.
This is because in the state of a solution, if stored for a long time, the resin may precipitate or decompose due to moisture absorption.

Further, this powder is converted into, for example, N, N-dimethylformamide, N, N-dimethylacetamide, N-
A polyimide resin solution can be obtained by dissolving the powder in a polar solvent such as methyl-2-pyrrolidone.

The polyimide resin solution according to the present invention thus prepared exhibits at least about twice the solubility of the conventional polyimide resin, and is 10 to 10 times more polar organic solvent.
It is possible to dissolve up to 20%. Therefore, the polyimide resin solution according to the present invention, in which the polyimide resin is dissolved in the polar organic solvent up to 10 to 20%, has a viscosity sufficient for film forming and a self-supporting film can be obtained. In addition, when used as an adhesive or the like, a sufficient thickness can be obtained by one application when applied.
It is possible to form a film excellent in bonding workability that can reduce the number of steps and bonding reliability such that cracks do not occur.

As described above, the polyimide resin solution according to the present invention shows remarkable solubility in polar organic solvents as compared with the conventional one. Furthermore, it has excellent heat resistance and insulation properties, and also has a sufficiently low glass transition temperature, low water absorption, and film moldability enough to enable lamination.
Conventionally, a polyamic acid had undergone a complicated process of imidization after film formation, whereas the polyimide resin solution according to the present invention produced a polyimide resin without any workability related to imidization, and used an organic solvent for use. And processed into various molded products such as films and metal laminates.

Although the polyimide resin solution according to the present invention has been described including the production method, the present invention is not limited to only these embodiments, and the present invention is not limited thereto. The present invention can be implemented in various modified, modified, and modified forms based on the knowledge of a trader.

[0076]

Next, examples of the present invention will be described more specifically, but the present invention is not limited only to these examples. In Examples, the glass transition temperature was measured by TMA, and the water absorption was measured using ASTM-5.
According to No. 70, a change in weight after immersion in pure water at 20 ° C. was measured.

[0077]

Example 1 In an ice bath, 500 m equipped with a stirrer
In a three-neck separable flask, 18.7 g (45.6 mmol) of 2,2-bis ((4-aminophenoxy) phenyl) propane (hereinafter, abbreviated as BAPP) and N, N-dimethylformamide (hereinafter, DMF) 239.6 g was added, and the mixture was stirred and dissolved sufficiently in a nitrogen atmosphere, and then 2,2-bis (4-hydroxyphenyl) propanedibenzoate-3,3,2 was added.
3 ', 4,4'-tetracarboxylic dianhydride (hereinafter referred to as ESDA
Abbreviated. ) 25.7 g (44.6 mmol) were charged,
The wall of the separable flask was washed with 10 g of DMF. After stirring for about 1 hour, the mixture
A solution prepared by dissolving 6 g of ESDA in 5.4 g of DMF was used.
The addition of the varnish viscosity in the flask was completed to obtain a polyamic acid.

Here, a film was prepared to measure the glass transition temperature and the water absorption in the imidized state of the obtained polyamic acid solution. Film formation is performed as follows. In 100 g of a polyamic acid varnish, 10 g of acetic anhydride, 10 g of isoquinoline, and 10 g of DMF were added.
After sufficient stirring, the mixture was applied on a PET film with a coater at intervals of 0.3 mm, heated in an oven at 80 ° C. for 10 minutes, peeled off the PET film, and fixed at the end to remove the PET film.
The temperature was continuously raised from 00 ° C. to 250 ° C., heated for 5 minutes and imidized to obtain a polyimide film having a thickness of 30 μm.

In order to carry out imidation in a solution state of polyamic acid, acetic anhydride is added to a polyamic acid solution at room temperature.
g, 10 g of pyridine and 100 g of DMF were added, and the mixture was stirred for several tens minutes to several hours to perform imidization.

The obtained polyimide resin solution (200 g) was separated, dropped into 2 liters of methanol, and filtered to obtain a polyimide resin. In addition, vacuum oven 100 ℃
, And vacuum-dried for 1 day to obtain a powder.

The resulting polyimide resin powder was N, N-
Dimethylformamide (hereinafter referred to as DMF), N-
Methyl-2-pyrrolidone (hereinafter abbreviated as NMP), m
-Cresol was dissolved in each polar organic solvent at a concentration of 10% by weight, 15% by weight, and 20% by weight. Further, the water absorption (%) and the glass transition temperature (° C.) of the obtained polyimide resin were measured.

The polyimide resin used in the present invention has a solid content concentration of 10%. An NMP solution of 10% is applied to a glass plate having a size of 3000 × 300 mm to a thickness of 0.3 mm by an applicator. After drying at 150 ° C. for 5 minutes, the polyimide film was peeled off from the glass substrate, and both ends of the obtained semi-dried polyimide film were fixed.
It was dried at 00 ° C. and 250 ° C. for 5 minutes to obtain a 30 μm polyimide film. The water absorption of the thus prepared polyimide film was measured.

The glass transition temperature (° C.) of the film obtained by the above method was measured using a DMS (manufactured by Seiko Electronics Co., Ltd., DMS
200) in the tensile mode. Table 1 shows the measurement results of the water absorption and the glass transition temperature.

[0084]

[Table 1]

(Examples 2 to 10) Using the raw materials shown in Table 1, polyimide films and films prepared from the solutions were obtained in the same manner as in Example 1, and the solubility and water absorption of various polar organic solvents were measured. An evaluation was performed. Table 1 shows the results.

(Comparative Examples 1 to 5) Using the raw materials shown in Table 2,
A polyimide resin powder was obtained in the same manner as in Example 1. Table 2 shows the evaluation results.

[0087]

[Table 2]

According to Examples 1 to 10, the polyimide resin solution according to the present invention was 10% or more in NMP or DM
A polyimide molded article which is a solution of F in a polar organic solvent and has excellent properties such as a glass transition temperature of 200 ° C. or less and a water absorption of 1.0% or less can be produced with remarkably good processability.

On the other hand, as shown in Comparative Examples 1 to 5,
Polar organic solvent solution with polyimide resin of other structure,
If the content is 10% or more, the film cannot be produced with good moldability.

[0090]

As described above, the polyimide resin solution according to the present invention exhibits remarkable solubility as compared with the conventional one.
Furthermore, when the polyimide resin solution according to the present invention is used, a heat-resistant, excellent insulating property, and a molded article such as a film having a glass transition temperature and a low water absorption that are sufficiently low to enable pasting processing are produced. And good film formability. Therefore, conventionally, the polyamic acid had undergone a complicated continuous process of imidization after film formation, whereas the use of the polyimide resin solution according to the present invention produced a polyimide resin without a problem of processability related to imidation, When used as appropriate, it can be processed into various molded products such as films and metal laminates by dissolving in a solvent, and in addition to greatly improving workability, it also has excellent properties such as low water absorption and low glass transition temperature. However, it can be optimally used for electronic devices with high functionality, high performance, and miniaturization.

Claims (6)

[Claims] 1. A method in which a polyimide resin is used in a polar organic solvent.
% Of a polyimide resin solution. 2. The general formula (1): ## STR1 ## (Wherein, R ₁ is a chemical formula 2 At least one selected from organic groups represented by
₂ represents a divalent organic group. ), Having film formability, and having a glass transition temperature of
A polyimide resin solution, characterized in that a polyimide resin having a water absorption of 200% or less and a water absorption of 1% or less is dissolved in a polar organic solvent by 10% or more. 3. In the general formula (1), R ₂ is The polyimide resin solution according to claim 2, wherein n is at least one kind represented by the formula (where n represents 1 to 10). 4. The method for producing a polyimide resin solution according to any one of claims 1 to 3, wherein the polyimide resin comprises a tetracarboxylic dianhydride and an aromatic diamine in a polar organic solvent. A method for producing a polyimide resin solution, comprising subjecting a polyamic acid obtained by the reaction to dehydration and ring closure in a solution. 5. The weight average molecular weight of the polyamic acid, which is a precursor of the polyimide resin, is adjusted to 50,000 to 250,000.
The method for producing a polyimide resin solution according to claim 4, wherein: 6. The dehydration and ring closure of the polyimide resin after the polyamic acid solution has been mixed with at least one carboxylic anhydride containing acetic anhydride and at least one amine containing β-picoline. The method for producing a polyimide resin solution according to claim 4 or 5, wherein the method is performed.