JPH07149896A - Production of polyamic acid solution - Google Patents

Abstract

PURPOSE:To obtain a highly concentrated, highly viscous and homogeneous polyamic acid solution by simple operation using simple apparatus and free from foam grasping, useful as, e.g. a raw material for polyimides, by mixing and reacting a tetracarboxylic acid component and diamine component and a solvent through autorotation/revolution centrifugal mixing process. CONSTITUTION:A solution prepared by mixing a tetracarboxylic acid component (e.g. pyromellitic dianhydride) and a diamine component [e.g. 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl] and a solvent (e.g. gamma-butylolactone) to effect reaction is fed into an autorotation/revolution centrifugal mixer where the solution is rapidly agitated and polymerized at room temperature, thus the highly concentrated, highly viscous and homogeneous polyamic acid solution is obtained by simple operation using simple apparatus. This solution is free from foam grasping and useful as a precursor for polyimides.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyamic acid solution useful as a polyimide precursor, and more particularly to a method for producing a highly viscous polyamic acid solution.

[0002]

2. Description of the Related Art Polyimide is widely used as a resin having excellent heat resistance and mechanical strength as a material for electronic, electrical and optical applications. Polyimide is usually produced by subjecting a polyamic acid obtained by reacting a reactive derivative of tetracarboxylic acid with a diamine to heat dehydration and ring closure. When the tetracarboxylic acid reactive derivative and diamine are solid at room temperature, it is easier to carry out the reaction operation by dissolving the respective components in a solvent before mixing and reacting them. It is often done.

When a reactive derivative of a tetracarboxylic acid and a diamine are mixed and reacted in the presence of an amide solvent such as N-methylpyrrolidone, a solid is precipitated in the initial stage of the reaction, and when stirred, a uniform polyamic acid is obtained over time. A solution is obtained, and if this is carried out at 150 ° C. or higher, the condensation reaction sequentially occurs to obtain a polyimide.

The viscosity of the polyamic acid solution ranges from 0.1 to 100,000 poises or more depending on the molecular structure, the degree of polymerization and the concentration, but especially in applications other than the use as a thin film coating material, the concentration of the solution is as high as possible. Is desirable.

However, high-concentration polyamic acid is generally highly viscous, and it may be difficult to stir and mix during the reaction. Therefore, selection of reaction raw materials, pretreatment of reaction raw materials,
Various devises have been made regarding devices and operations for mixing and stirring.

For example, a method is known in which the viscosity of a polyamic acid solution produced by partially hydrolyzing or esterifying tetracarboxylic dianhydride in advance with water or alcohol is lowered. Further, a method of avoiding a rapid increase in viscosity can be adopted by controlling the rate of adding tetracarboxylic acid to the diamine solution. Alternatively, a method has been proposed in which a continuous processing apparatus is used, in which case the shapes of the outer container and the rotating body are optimized in order to obtain a strong shearing force.

[0007]

The method of lowering the viscosity of a polyamic acid solution by partially hydrolyzing or esterifying tetracarboxylic dianhydride with water or alcohol in advance requires an additional operation and is economically disadvantageous. It is a disadvantage.

There is a problem that a special adjusting device and a long time are required for addition in order to control the rate of adding the tetracarboxylic acid to the diamine solution. Further, in a continuous device, it is preferable to produce a single polyamic acid, but in order to produce many kinds of products required for electronics, cleaning and adjustment of the device due to product type change are complicated and not always necessary. Not desirable.

Further, in the case of producing a desirable high-viscosity polyamic acid for thick film coating or for an interlayer insulating film, it is necessary to dissolve and homogenize a solid once produced when a reactive derivative of tetracarboxylic acid and a diamine are mixed. A stirrer with a large driving force is required, and a stirring blade type stirrer requires a special blade shape to obtain a uniform solution.
Further, in such stirring, the obtained polyamic acid solution is unlikely to be uniform, and since air bubbles are entrapped from the interface with air, the film formed from the obtained polyamic acid solution has increased scattering. Is not suitable for optical applications,
Since the withstand voltage is lowered, there are various problems such as unsuitability for electric / electronic applications.

The present invention provides a method for producing a highly concentrated and highly viscous polyamic acid solution which is uniform and has no bubbles entrapped by a simple operation using a simple apparatus.

[0011]

In order to solve the problems of homogeneity and foam entrapment in the method of producing a polyamic acid by mixing a reactive derivative of a tetracarboxylic acid and a diamine, the present inventors have previously proposed A solution of a tetracarboxylic acid component and a diamine component mixed and dissolved was prepared respectively, and the behavior of each component solution when observed in a container so that each of these component solutions had an approximately equivalent amount was observed. The carboxylic acid solution, especially the oligomer solution consisting of tetracarboxylic acid and diamine, and the diamine solution were not immediately mixed due to the difference in viscosity between these solutions, and it was observed that two-phase separation remained at a low solution viscosity. It was found that the entrapment of bubbles was remarkable when stirred with a stirrer equipped with. Therefore, it was found that a high-viscosity and homogeneous solution free from bubbles being trapped can be easily obtained by polymerizing the mixed solution separated into these two layers by rapidly and homogeneously mixing by a revolving centrifugal method. It was

That is, the present invention provides a method for producing a polyamic acid solution by mixing and reacting a tetracarboxylic acid component, a diamine component and a solvent, or a method in which a tetracarboxylic acid component solution and a diamine component solution are mixed and reacted. In the method for producing an acid solution, the method is a method for producing a polyamic acid solution, which comprises mixing by an auto-rotation centrifugal mixing method.

The tetracarboxylic acid component solution is a solution of a tetracarboxylic acid component dissolved in a solvent. The solvent is not particularly limited, and amide solvents such as N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, γ-butyrolactone, α-methyl-γ-butyrolactone, γ-valerolactone, δ- Valerolactone,
Lactones such as γ-caprolactone and ε-caprolactone, carbonates such as ethylene carbonate and propylene carbonate, esters such as butyl acetate, ethyl cellosolve acetate and butyl cellosolve acetate, ethers such as dibutyl ether, diethylene glycol dimethyl ether and triethylene glycol dimethyl ether. , Ketones such as methyl isobutyl ketone, cyclohexanone, and acetophenone, alcohols such as butanol, octanol, and ethyl cellosolve, as well as chain or cyclic urea-based, sulfoxide-based, sulfone-based, hydrocarbon-based, halogen-based solvents, etc. I can give you.

The tetracarboxylic acid component has only to be substantially reactive as a tetracarboxylic acid, and is a tetracarboxylic acid dianhydride, an ester, a derivative such as an acid halide, or an oligomer with a diamine. Such a tetracarboxylic acid is not particularly limited and may be represented by the following general formula

[0015]

[Chemical 1]

Any ^one represented by (R ¹ is a tetravalent organic group) may be used. R ¹ is, for example,

[0017]

[Chemical 2]

(X is a single bond, -O-, -S-, -C (=
O)-, -S (= O)-, -C (CH ₃)₂-, -C (C
F₃)₂− A hydrogen atom attached to a ring carbon is optionally
Alkyl groups such as methyl group, ethyl group, i-propyi group
Group, n-propyl group, butyl group, or fluoro group
Alkyl group, for example, trifluoromethyl group, pentaflu
It may be substituted with an oroethyl group. )
Those that can be suitably used.

Specifically, benzenetetracarboxylic acid,
For example, pyromellitic acid, trifluoromethylbenzenetetracarboxylic acid, bistrifluoromethylbenzenetetracarboxylic acid, difluorobenzenetetracarboxylic acid, and biphenyltetracarboxylic acid, terphenyltetracarboxylic acid, benzophenonetetracarboxylic acid,
Hexafluoroisopropylidene diphthalic acid, oxydiphthalic acid, cyclobutane tetracarboxylic acid, bicyclo
Examples thereof include (2,2,2) oct-7-ene-2,3,5,6-tetracarboxylic acid.

A reaction product obtained from tetracarboxylic acid anhydride and less than 0.5 equivalent of water, alcohol or diamine can also be used as a tetracarboxylic acid component, and the reaction product with water or alcohol can be used in a high concentration solution. Oligomerized tetracarboxylic acid anhydride, which is useful for adjusting the degree of polymerization and viscosity and obtained with less than 0.5 equivalent of diamine, and its reaction product with water or alcohol have high concentration and low viscosity dissolution of tetracarboxylic acid component. Useful for. Furthermore, the oligomerized tetracarboxylic acid component is 5
It is also possible to adjust the degree of polymerization by performing a cooking treatment at 0 to 100 ° C. for about 1 hour.

The diamine component solution is a solution containing at least one kind of diamine, and the kind of diamine is not particularly limited. However, the general formula H ₂ N—R ² —NH ₂ (R ² is a divalent organic compound is used. The group represented by () can be used. R ² is, for example,

[0022]

[Chemical 3]

(X is a single bond, -O-, -S-, -C (=
O)-, -S (= O)-, -C (CH ₃)₂-, -C (C
F₃)₂− A hydrogen atom attached to a ring carbon is optionally
Alkyl groups such as methyl group, ethyl group, i-propyi group
Group, n-propyl group, butyl group, or fluoro group
Alkyl group, for example, trifluoromethyl group, pentaflu
It may be substituted with an oroethyl group. )
Those that can be suitably used.

Specifically, o-, m-, p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,4-diaminoxylene, 2,4-diaminodurene, dimethyl 4 , 4'-diaminodiphenyl, dialkyl 4,4'-diaminodiphenyl, dimethoxy 4,4'-diaminodiphenyl, diethoxy 4,
4'-diaminodiphenyl, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether,
3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 1,3-bis (3- Aminophenoxy) benzene, 1,3-bis (4
-Aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl, bis (4- (3-aminophenoxy) phenyl) sulfone, bis (4 -(4-aminophenoxy) phenyl) sulfone, 2,2-bis (4- (4-aminophenoxy) phenyl) propane,
2,2-bis (4- (4-aminophenoxy) phenyl) hexafluoropropane, 2,2-bis (4- (3
-Aminophenoxy) phenyl) propane, 2,2-bis (4- (3-aminophenoxy) phenyl) hexafluoropropane, 2,2-bis (4- (4-amino-2)
-Trifluoromethylphenoxy) phenyl) hexafluoropropane, 2,2-bis (4- (3-amino-5)
-Trifluoromethylphenoxy) phenyl) hexafluoropropane, 2,2-bis (4-aminophenyl)
Hexafluoropropane, 2,2-bis (3-aminophenyl) hexafluoropropane, 2,2-bis (3-
Amino-4-hydroxyphenyl) hexafluoropropane, 2,2-bis (3-amino-4-methylphenyl) hexafluoropropane, 4,4′-bis (4-aminophenoxy) octafluorobiphenyl, 4,4 ′
-Diaminobenzanilide, 2,2'-bis (trifluoromethyl) diaminodiphenyl 3,5-diaminobenzotrifluoride, 2,5-diaminobenzotrifluoride, 3,3'-bistrifluoromethyl-4,4'-
Diaminobiphenyl, 3,3'-bistrifluoromethyl-5,5'-diaminobiphenyl, bis (trifluoromethyl) -4,4'-diaminodiphenyl, bis (fluorinated alkyl) -4,4'-diaminodiphenyl, Dichloro-4,4'-diaminodiphenyl, dibromo-
4,4'-diaminodiphenyl, bis (fluorinated alkoxy) -4,4'-diaminodiphenyl, diphenyl-
4,4'-diaminodiphenyl, 4,4'-bis (4-
Examples include aminotetrafluorophenoxy) tetrafluorobenzene, 4,4′-bis (4-aminotetrafluorophenoxy) octafluorobiphenyl, 4,4′-binaphthylamine and the like.

As the other diamine, a diamine used for the purpose of imparting various functions can be used in combination. For example, in order to improve the adhesion to the substrate, the general formula

[0026]

[Chemical 4]

(R ³ and R ⁴ are the same or different alkylene groups having 1 to 10 carbon atoms or divalent aromatic groups which may have a substituent, and p is an integer of 1 to 50. ) Is used in combination with the above diamine.

The siloxydiamine is not particularly limited, but for example, 1,3-bis (3-aminopropyl)-
1,1,2,2-tetramethyldisiloxane, 1,3-
Examples include bis (3-aminobutyl) -1,1,2,2-tetramethyldisiloxane, bis (4-aminophenoxy) dimethylsilane, and 1,3-bis (4-aminophenoxy) tetramethyldisiloxane. .

The polyamic acid produced in the present invention can be copolymerized or converted with a polyamic acid solution, a polyamic acid, a polyimide, or various compounds for the purpose of handling or treating them or improving their physical properties. For example, a maleimide compound may be copolymerized in order to reduce the adhesiveness to the substrate or the stress between the substrate and the substrate when the coating film is formed by coating the substrate and baking it.

As the maleimide compound, bismaleimide is preferable, and 2,2'-bis (4-maleimidophenyl) hexafluoropropane and 2,2'-bis (4-
(4-maleimidophenoxy) phenyl) hexafluoropropane, 2,2′-bis (4- (2-trifluoromethyl-4-maleimidophenoxy) phenyl) hexafluoropropane, 4,4′-bis (4-maleimidophenoxy) ) Octafluorobiphenyl, 4,4′-bismaleimidediphenylmethane, 4,4′-bismaleimidediphenylether, 4,4′-bismaleimidebenzanilide, 2,2′-bis (4- (4-maleimidophenoxy) ) Phenyl) propane etc. can be mentioned.

The revolving centrifugal mixing method in the present invention is as follows:
This is a mixing method which comprises stirring the contents by rotation of the container and adding centrifugal force by revolution. As an apparatus suitable for the revolving centrifugal mixing method in the present invention, for example, a rotary type mixer described in JP-A-63-310629 can be cited, and as a commercially available apparatus, for example, , SKB manufactured by IKS Co., Ltd.
350, but is not limited thereto.

The present invention is characterized in that the mixing and the reaction can be carried out in a short time by carrying out the rotation and the revolution at the same time, and the obtained polymer is hardly influenced by the atmospheric gas. ing.

That is, the method of the present invention is characterized in that rotation and revolution are simultaneously applied to the object to be treated, but it is also possible to perform only stirring by rotation in advance and then perform defoaming treatment by revolution. However, it is not preferable as compared with the method of treating at the same time. In this case, stirring may be replaced by rotation of the container itself, and revolution may be replaced by a method such as a centrifugal settler.

The rotation is carried out by aligning the center line of the container with the axis of rotation and applying a rotation of 0.1 to 5000 rpm to the container, but the method is not particularly limited. For example, rotation can be performed by a method using a rotating machine provided on a revolving substrate, or a method using a rotating machine for revolution or an independent rotating machine through a torque transmission device such as a pulley or a gear.
Further, the revolution is performed by rotation of 0.1 to 5000 rpm about a line that does not pass through the center of gravity of the container as a rotation axis. When the rotation rate is 0.1 rpm or less, the effect of stirring is low, the time required for stirring is long and not practical, and when it is 5000 rpm or more, it is difficult to maintain stable rotation, which is not preferable. Further, when the revolution is 0.1 rpm or less, sufficient centrifugal force does not suspend the contents of the container, and bubbles are trapped in the obtained polyamic acid, and it is difficult to maintain stable rotation at 5000 rpm or more. Neither is preferable.

The axis of revolution and the axis of revolution may or may not be parallel to each other. Therefore, the angles formed by them are arbitrary, but preferably the container is inclined toward the center of revolution, and the axis of revolution and the axis of revolution are the same. The angle formed by is 10 to 80 degrees, more preferably 30 to 60 degrees, but is usually about 45 degrees.
The present invention is described below with reference to examples, but the present invention is not limited to these modes.

[0036]

【Example】

Example 1 225.49 in a glass 4-neck separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen introducing tube.
g (0.704 mol) of 2,2′-bis (trifluoromethyl) -4,4′-diaminodiphenyl (hereinafter,
It is called "ABL". ), 399.32 g (1.8307)
mol) pyromellitic dianhydride (hereinafter referred to as “PMD
"A". ) 147.4741 g (0.1735 m)
2,2′-bis (4- (4-maleimido-2-)
Trifluoromethylphenoxy) phenyl) hexafluoropropane (hereinafter referred to as “OFM”) was charged, and 1
343 g of γ-butyrolactone was added and stirred at 60 ° C. for 1 hour to prepare an oligomer solution of tetracarboxylic acid anhydride. Similarly, 358.83g of ABL (1.12mo
1), 8.11 g (0.0346 mol) of 1,3-bis (3-aminopropyl) tetramethyldisiloxane (hereinafter referred to as “TMDS”) were charged, and 640 g of γ-butyrolactone was added and dissolved with stirring at room temperature. Then, a diamine component solution was prepared.

After clarifying the relationship between the set flow rate and set time of the precision metering pump and the liquid supply amount and confirming the quantitative property, the prepared tetracarboxylic acid oligomer solution and diamine component solution were each adjusted to 20 ml / min. Flow rate 3.4 minutes and flow rate of 10 ml / min 3.13
The amount of tetracarboxylic acid and diamine component was equimolar to a 150 ml polyethylene bottle and the container was sealed. The metered injection amount of the tetracarboxylic acid oligomer solution and the diamine component solution is 82.355, respectively.
g (43.854 mmol) and 38.180 g (4
The charged molar ratio (tetracarboxylic acid component / diamine component) was 3.702 mmol and was 1.002. At this stage, the two liquids were phase-separated and the increase in viscosity, that is, the progress of polymerization was not observed.

Subsequently, the mixture was rapidly mixed and polymerized at room temperature with an orbiting centrifugal mixer (SNB-350 manufactured by IKS Co., Ltd.) to obtain a transparent viscous polyamic acid solution having a solid content concentration of 36.5 wt%. It was That is, the polyethylene bottle and the dummy described above are fixed to two container holders that are arranged at the target position with respect to the revolution axis and are inclined inward so that the rotation axis and the revolution axis form 45 degrees, and the revolution is revolved. The rotation was started by setting the number scale to 9 and the rotation rotation scale to 3. At this time, the revolution speed of revolution was about 1300 rpm, and the revolution speed of rotation was about 100 rpm. After about 30 seconds of rotation, the scale of rotation was set to 0 (the rotation was not stopped), the revolution was maintained at the same number of revolutions, and 40 seconds later, the revolution was stopped to carry out the mixed polymerization operation.

When the apparent viscosity of the obtained polyamic acid solution was measured after 24 hours, it was 62,000 poise, and it was a homogeneous solution with no biting of bubbles. Example 2 10.706 g of A in a 150 ml polyethylene bottle
BL (33.432 mmol) was weighed, and 102
g of N, N-dimethylacetamide was added and dissolved.
To this, an additional 7.294 g of PMDA (33.44
(0 mmol) was charged and the container was sealed as it was.

Subsequently, the mixture was rapidly mixed and polymerized under the same conditions as in Example 1 using a revolving centrifugal mixer to obtain a transparent viscous polyamic acid solution having a solid content concentration of 15 wt%. When the apparent viscosity of the obtained polyamic acid solution was measured after 24 hours, it was 2700 poise, and it was a homogeneous solution with no bubble biting.

Example 3 10.396 in a glass 4-neck separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen inlet tube.
g (32.464 mmol) of ABL, 19.104 g
Biphenylcarboxylic acid dianhydride (64.932 mmol) was charged, 166 g of γ-butyrolactone was added, and the mixture was stirred at room temperature for 30 minutes to prepare an oligomer solution of tetracarboxylic acid anhydride. On the other hand, 6.501 g (32.46
38 g of N-methylpyrrolidone was added to oxydianiline (4 mmol) and dissolved by stirring at room temperature to prepare a diamine component solution.

97.750 g (16.234 mmol) of an oligomer solution of tetracarboxylic acid anhydride and 22.250 g (16.232 mmol) of a diamine component solution were added to 15 parts.
The bottle was weighed and sealed in a 0 ml polyethylene bottle. At this stage, the two liquids were phase-separated and no increase in viscosity, that is, no progress of polymerization was observed.

Subsequently, the mixture was rapidly mixed and polymerized at room temperature with an orbiting centrifugal mixer (SNB-350 manufactured by IKS Co., Ltd.) to obtain a transparent viscous polyamic acid solution having a solid content concentration of 15.0 wt%. It was That is, the polyethylene bottle and the dummy described above are fixed to two container holders which are arranged at the target position with respect to the revolution axis and are inclined inward so that the revolution axis and the revolution axis form 45 degrees, and the revolution is revolved. The rotation was started by setting the number scale to 9 and the rotation rotation scale to 3. At this time, the revolution speed of revolution was about 1300 rpm, and the revolution speed of rotation was about 100 rpm. After about 30 seconds of rotation, the scale of rotation was set to 0 (the rotation was not stopped), the same rotation number was maintained only for the revolution, and the revolution was stopped 40 seconds later to carry out the mixed polymerization operation.

When the apparent viscosity of the obtained polyamic acid solution was measured after 24 hours, it was 2000 poises.
It was a homogeneous solution with no bubble biting. Comparative Example 1 Using the tetracarboxylic acid oligomer solution and the diamine solution prepared in Example 1, the tetracarboxylic acid and the diamine component were mixed in an approximately equimolar amount of 150 at the same pump flow rate conditions.
It was metered into a ml polyethylene bottle and sealed.

The metered injection amount of the tetracarboxylic acid oligomer solution and the diamine component solution is 82.51, respectively.
2 g (43.937 mmol) and 38.178 g
The charged molar ratio (tetracarboxylic acid component / diamine component) was 1.004 at (43.780 mmol), and at this stage, the two liquids were phase-separated and the increase in viscosity, that is, the progress of polymerization was not observed.

Next, when stirring was started using a stirrer equipped with a stirring blade made of Teflon in this container, the viscosity suddenly increased and stirring became impossible. After that, even if the container was left to stand, a uniform solution was not obtained.

Comparative Example 2 Using the tetracarboxylic acid oligomer solution and the diamine solution prepared in Example 1, the tetracarboxylic acid and the diamine component were mixed in an approximately equimolar amount of 150 under the same pump flow rate conditions.
It was metered into a ml polyethylene bottle and sealed.

The metered injection amount of the tetracarboxylic acid oligomer solution and the diamine component solution was 82.31 respectively.
5 g (43.833 mmol) and 38.177 g
The molar ratio (tetracarboxylic acid component / diamine component) charged at (43.779 mmol) was 1.001, and at this stage, the two liquids were phase-separated and the increase in viscosity, that is, the progress of polymerization was not observed.

This was subsequently treated at room temperature with the revolving centrifugal mixer used in Example 1. However, the revolution is reduced to 200 rpm and only the rotation is performed at about 100 rpm.
It was set to 0 seconds. In this case, stirring was sufficiently performed and a polyamic acid solution was obtained, but generation of bubbles was visually observed.

Comparative Example 3 Using the oligomeric solution of tetracarboxylic acid prepared in Example 1 and the diamine solution, the equimolar amounts of tetracarboxylic acid and diamine components were adjusted to 150 at the same pump flow rate conditions.
It was metered into a ml polyethylene bottle and sealed.

The metered amounts of the tetracarboxylic acid oligomer solution and the diamine component solution were respectively 82.59.
5 g (43.982 mmol) and 38.186 g
The molar ratio (tetracarboxylic acid component / diamine component) charged at (43.790 mmol) was 1.004, and at this stage, the two liquids were phase-separated and the increase in viscosity, that is, the progress of polymerization was not observed.

Subsequently, at room temperature, a centrifuge (domestic centrifuge H103N) was used to rotate only about 3000 rpm.
For 70 seconds. In this case, no mixing was done and the contents remained in two layers.

[0053]

EFFECTS OF THE INVENTION When a tetracarboxylic acid component and a diamine component are mixed and polymerized to produce a highly viscous polyamic acid solution, in the method of the present invention, the rotation and the revolution are simultaneously performed to shorten the mixing and reaction. It is possible to carry out in a short time, and it is possible to produce a uniform polyamic acid solution free of bubbles from being entrapped.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Politics Hasegawa 2805 Imafuku Nakadai, Kawagoe City, Saitama Central Research Institute Tokyo Co., Ltd. Tokyo Research Institute Co., Ltd.

Claims (2)

[Claims] 1. A method for producing a polyamic acid solution by mixing and reacting a tetracarboxylic acid component, a diamine component, and a solvent, wherein the polyamic acid solution is mixed by a rotation / revolution centrifugal mixing method. 2. A method for producing a polyamic acid solution by mixing and reacting a tetracarboxylic acid component solution and a diamine component solution, wherein the polyamic acid solution is mixed by a rotation / revolution centrifugal mixing method.