KR100600449B1 - Unsymmetric Diamine Monomer Having Trifluoromethyl and Soluble Aromatic Polyimides Prepared by Using the Same - Google Patents

Abstract

The present invention is a diamine monomer represented by the following general formula (II) and used in the production of polyimide characterized in that a trifluoromethyl group is introduced asymmetrically; And

The present invention relates to a polyimide, which is represented by the following structural formula (V) in which the diamine monomer and the tetracarboxylic dianhydride monomer are already imidized, and even after the imidization is fully performed, the solubility in the organic solvent is sufficient, so that the processability is excellent. In addition, since the excellent physical properties of polyimide can be maintained, it is useful as an electrical, electronic or optical mechanical material material.

Description

Unsymmetric Diamine Monomer Having Trifluoromethyl and Soluble Aromatic Polyimides Prepared by Using the Same             

1 is a hydrogen atom nuclear magnetic resonance spectroscopy spectrum of the diamine monomer synthesized in Example 1.

2 is a carbon atom nuclear magnetic resonance spectroscopy spectrum of the diamine monomer synthesized in Example 1.

3 is an infrared spectroscopy spectrum of the polyamic acid and polyimide synthesized in Example 2 and the polyimide synthesized in Comparative Example 1.

4 is a hydrogen atom nuclear magnetic resonance spectroscopy spectrum of the polyamic acid and polyimide synthesized in Example 2.

5 is a diagram showing the DSC of the polyamic acid and polyimide synthesized in Example 2 and the polyimide synthesized in Comparative Example 1. FIG.

Field of invention

The present invention relates to a diamine monomer having an asymmetric structure having a trifluoromethyl group and a soluble aromatic polyimide prepared using the same. More specifically, the present invention provides a diamine monomer synthesized by appropriately adjusting the molecular structure in order to suppress various interactions between polyimide chains, and a soluble aromatic poly which is dissolved in an organic solvent and processed after imidation is fully performed. It's about mead.

Background of the Invention

The polyimide obtained by polymerizing a diamine monomer and a tetracarboxylic dianhydride monomer is excellent in heat resistance, mechanical strength, dimensional stability, and excellent in flame retardancy and electrical insulation. Due to the excellent physical properties, polyimide has been used in various application fields such as electrical and electronic devices, aerospace equipment, and transportation equipment, and various forms of research have been conducted according to the intended use.

In general, the aromatic polyimide is processed in the form of an intermediate polyamic acid because it is not dissolved in an organic solvent at all in the final stage of imidization and is not processed because it is decomposed before melting and is processed. The final final product is manufactured using a two-step process. However, in the two-step process, not only the intermediate polyamic acid is unstable, but also by-products such as water generated in the imidization process come out, making it difficult to process the desired form.

In order to solve the problems of the two-step process while maintaining excellent properties of the aromatic polyimide, soluble polyimide and moldable which can be easily processed into a film or fiber form due to sufficient solubility in organic solvent even after complete imidation Research on polyimide is ongoing.

To prepare soluble polyimide, the method of twisting the plate form between the benzene rings, the method of bending the rigid chain structure by introducing the bent structure, and the introduction of functional groups with steric hindrance to remove the strong interaction between the polyimide chains. The method and the method of copolymerizing together the component which is excellent in solubility with respect to an organic solvent are known.

On the other hand, the introduction of perfluoroalkyl groups, including trifluoromethyl groups, into the polyimide backbone, through the carbon-fluorine bonds stronger than the carbon-hydrogen bonds, does not significantly reduce the heat resistance of the resulting polyimide. By suppressing the various interactions of the polyimide, not only the solubility of the polymer produced is greatly increased, but also a significant decrease in moisture absorption, dielectric constant, refractive index, etc., due to the low polarizability of the fluorine atom.

Accordingly, the present inventors synthesized a diamine monomer having asymmetric trifluoromethyl group, and polymerized with various general-purpose tetracarboxylic dianhydrides, thereby soluble aromatic polys having excellent solubility in organic solvents even after imidation was completely formed. Meade was developed.

An object of the present invention is to provide a diamine monomer in which a trifluoromethyl group is asymmetrically introduced in order to suppress various interactions of the polyimide.

Another object of the present invention is to provide a polyimide excellent in processability by using a diamine monomer having a trifluoromethyl group asymmetrically introduced therein and having sufficient solubility in an organic solvent even after the imidation is fully performed.

The above and other objects of the present invention can be achieved by the present invention described below. Hereinafter, the content of the present invention will be described in detail.

The diamine monomer prepared according to the present invention is represented by formula (II) as 2-trifluoro-4,4'-diaminodiphenyl ether.

According to the following Scheme 1, the diamine monomer (II) is a die represented by the following structural formula (I) by reacting 2-chloro-5-nitrobenzotrifluoride and 4-nitrophenol in the presence of a basic calcium carbonate After the nitro compound is prepared, it is obtained through a reduction reaction of the nitro group.

The diamine monomer (II) is a 4,4'-diaminodi represented by the following structural formula (III) which is used as a raw material of Kapton ^TM which is currently commercialized, except that a suitable size of trifluoromethyl group is present on one side of the benzene ring. It has the same structure as phenyl ether.

As described above, when the functional groups are introduced asymmetrically, the solubility in organic solvents is greatly improved by canceling the symmetry between the resulting polyimide chains, thereby greatly reducing the interaction.

Soluble polyimide according to the present invention is represented by the following structural formula (V).

As indicated in Scheme 2 below, the diamine monomer and tetracarboxylic dianhydride monomer represented by Structural Formula (II) were dissolved in N-methylpyrrolidone (NMP) as a reaction solvent in the same equivalent amount, and stirred at room temperature for 8 hours. To form a polyamic acid. The concentration of the solution is suitably about 10-20% (weight of monomer (g) / amount of solvent (ml)). After diluting the concentration of the solution to 5-10%, the temperature is raised to 190 ° C. and stirred for at least 8 hours to imidize. At this time, it is good to remove the water generated during the reaction by continuing to add a small amount of chlorobenzene so that the imidization reaction proceeds effectively. Although xylene may be used instead of chlorobenzene, the resulting polyimide may have precipitation during the reaction due to its extremely poor solubility in xylene. When the reaction proceeds completely, the reaction solution is precipitated in a mixture of excess methanol and water, washed with hot water, alcohol, and acetone and dried in a vacuum oven.

After obtaining a polyamic acid prepared using the diamine monomer (II) in a powder state or a film in a polyamic acid state, there is a method of producing a polyimide by imidization at 300 ° C., but according to Scheme 2 The solubility in organic solvents is reduced compared to the case of the polyimide production method. Further, even when the polyimide powder according to Scheme 2 is obtained and heat treated at 300 ° C., the solubility is reduced.

Tetracarboxylic anhydrides used in the present invention are 1,2,4,5, -benzenetetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 2,2 ', 3,3'-benzophenone tetracarboxylic dianhydride, 3,3', 4,4'-diphenylethercarboxylic acid dianhydride, 2,2'3,3'-diphenylethercarboxylic acid Dianhydride, 3,3'-oxyphthalic acid dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2'-3,3'-biphenyltetracarboxylic dianhydride , 3,3 ', 4,4'-tetracarboxydiphenylsulfide dianhydride, 2,2', 3,3'-tetracarboxylic diphenylsulfide dianhydride, 3,3 ', 4,4'-tetra Carboxylic diphenyl sulfone dianhydride, 2,2 ', 3,3'-tetracarboxylic diphenyl sulfone dianhydride, 4,4'-hexafluoroisopropylidene diphthalic anhydride, 1,4,5,8- Naphthalene tetracarboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride Water or the like, which are used alone or in combination.

In addition, polyimide prepared using other dianhydrides other than benzenetetracarboxylic dianhydride was added to N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N-methylpi A tough film can be formed by melt | dissolving in polar aprotic organic solvents, such as a rollidone (NMP), and dimethyl sulfoxide (DMSO), and phenolic solvents, such as m-cresol.

The diamine monomer (II) of this invention can mix and use other diamine in the range which does not reduce solubility according to a use use. Diamines which can be mixed can be used as 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 2,4'-diaminodiphenyl Ether, 2,2'-diaminodiphenyl ether, 2,3'-diaminodiphenyl ether, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) Benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, p-phenylenediamine, m-phenylenediamine, o-phenylenediamine , p-aminobenzylamine, m-aminobenzylamine, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 2,2- Bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, bis (4-aminophenyl) sulfide, bis (3-aminophenyl) Sulfide, 3,4-diaminophenylsulfide, bis (4-aminophenyl) sulfoxide, bis (3-a Minophenyl) sulfoxide, 3,4-diaminophenyl sulfoxide, bis (4-aminophenyl) sulfone, bis (3-aminophenyl) sulfone, 3,4-diaminophenyl sulfone, 4,4'-diamino Benzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl ] Sulfone, bis [4- (4-aminophenoxy) phenyl] ether, 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy Benzoyl] benzene, 4,4'-bis [3- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4'-bis [3- (3-aminophenoxy) benzoyl] diphenyl ether, 4,4'-bis [4- (4-amino-alpha, alpha-dimethylbenzyl) phenoxy] benzophenone, 4,4'-bis [4- (4-amino-alpha, alpha-dimethylbenzyl) Phenoxy] diphenylsulfone, bis [4- {4- (4-aminophenoxy) phenoxy} phenyl] sulfone, 1,4-bis [4- (4-aminophenoxy) -alpha, alpha-dimethyl Benzyl] benzene, 1,3-bis [4- (4-aminophenoxy ) -Alpha, alpha-dimethylbenzyl] benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2 -Bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane and the like.

The diamine monomers and polyimides of the present invention can be more clearly understood by the following examples, which are only illustrative purposes of the present invention and are not intended to limit the scope of the invention.

The structure and physical properties of the monomers and polymers according to Examples and Comparative Examples were measured using the following method.

The structure of the synthesized material was confirmed from IR (ultraviolet spectroscopy) and NMR (nuclear magnetic resonance spectroscopy). IR diagrams were obtained from Bruker's FTIR spectrophotometer using KBr or film, and NMR diagrams were obtained by dissolving samples in dimethylsulfoxide-d6 using Bruker's Fourier Transform AC200 spectrometer (200 MHz). The inherent viscosity of the synthesized polymer was measured by dissolving the sample in N, N-dimethylacetamide (DMAc) solvent at a concentration of 0.5 g / dL and using a Cannon-Ubbelohde type viscometer at 30 ° C. It was. Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and Thermomechanical Analysis (TMA) used TA Instrument's TA 2200 thermal analyzer system (TGA 2050, DSC 2010, TMA 2940). In thermal analysis, TGA and DSC were measured at a temperature rise rate of 10 ° C./min, and TMA was measured at a temperature rise rate of 5 ° C./min. All of the thermal analyzes were measured under constant nitrogen airflow, and TGA analysis was performed under constant airflow. The 5% weight loss temperature was obtained from TGA analysis, the glass transition temperature (Tg) was selected at the midpoint of the slope of the curve in the DSC plot, and the coefficient of thermal expansion (CTE) was measured at temperatures between 50 and 250 ° C using TMA. Measured in the region.

Example 1

Synthesis of 2-trifluoro-4,4'-diaminodiphenyl ether

15.3 g (67.8 mmol) of 2-chloro-5-nitrobenzotrifluoride and 9.43 g (67.8 mmol) of 4-nitrophenol were dissolved in 100 ml of N, N-dimethylformamide, followed by potassium carbonate. 10.0 g (72.4 mmol) (K ₂ CO ₃ ) was added thereto, and the resultant was stirred at 150 ° C. for 6 hours. It was cooled to room temperature, diluted with 300 ml of chloroform, and extracted several times with distilled water to remove DMF and salts. The solvent was evaporated after removal of water by using anhydrous magnesium sulfate in the chloroform solution, and recrystallized with methanol to obtain 20.7 g (63.1 mmol) of a compound as a yellow dynamite, the yield was 93.0%. At this time, the melting point of the compound was dyne to 70 to 72 ℃.

15.0 g (45.7 mmol) of the compound was added to a 500 mL round flask with 250 mL of ethanol, and 41.0 g (216 mmol) of anhydrous tin chloride (SnCl ₂ ) was added thereto. 120 ml of concentrated hydrochloric acid was slowly added dropwise to the reaction, and the reaction mixture was refluxed for 12 hours. After the reaction, ethanol was evaporated, mixed with 400 ml of water, and then made basic by adding 10% sodium hydroxide solution to form a pale yellow diamine monomer. This was recrystallized in ethanol and vacuum sublimated at a temperature of 130 ℃ to give 7.92g (yield 64.6%) of white crystals. At this time, the melting | fusing point of the produced | generated diamine monomer was 109-110 degreeC.

Example 2

Preparation of Soluble Polyimide

0.80772 g (3.0112 mmol) of diamine monomer (II) is completely dissolved in purified 14 ml of NMP, and 0.93413 g (ODPA) of equivalent equivalent of 3,3 ', 4,4'-diphenylethercarboxylic acid dianhydride (ODPA) 3.0112 mmol) was added in a solid state, followed by stirring at room temperature for 8 hours to form a polyamic acid. 3.5 ml of NMP was further added to the solution, and the temperature was raised to 190 ° C. and stirred for 8 hours while removing water, a by-product generated during imidization, with a small amount of chlorobenzene. At this time, precipitation or gelation did not occur during the reaction. After cooling to room temperature, the viscous solution is precipitated in a mixture of methanol and water, filtered off, and the white precipitate is washed several times with excess water, hot methanol, and hot acetone, followed by vacuum drying at a temperature of 70 DEG C. Got it.

Some of the synthesized polymers were made into a 10% by weight DMAc solution and applied to a glass plate to remove the solvent for 24 hours at a temperature of 70 ° C. and vacuum to obtain a pale yellow transparent, tough film.

Example 3

It was prepared by the same method as Example 2 except for using 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride (BTDA) instead of ODPA. Soluble polyimide with no precipitation or gelling phenomenon was obtained during the reaction.

Example 4

It was prepared by the same method as in Example 2 except for using 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) instead of ODPA. Soluble polyimide with no precipitation or gelling phenomenon was obtained during the reaction. In this case, a reversible gelation phenomenon was observed in which the gelation occurred when the temperature of the polyimide solution decreased, and then changed to a fluid solution when the temperature was increased to 150 ° C. or higher.

Example 5

It was prepared in the same manner as in Example 2 except for using 1,2,4,5-benzenetetracarboxylic dianhydride (PMDA) instead of ODPA. In this case, precipitates formed during imidization and did not proceed fully imidization, and the resulting polymer was not dissolved in any organic solvent. This is because the polyimide synthesized from 1,2,4,5-benzenetetracarboxylic dianhydride used has a very rigid structure and does not show sufficient solubility.

Comparative Example 1

A polyimide was prepared in the same manner as in Example 2, except that 4,4'-diaminodiphenyl ether (III) was used instead of the diamine monomer (II). At this time, a precipitate formed during imidization to obtain a powder in which complete imidization did not proceed, and the polymer was not dissolved in an organic solvent. The results show that the introduction of trifluoromethyl groups asymmetrically has a great influence on the solubility improvement of the polyimide.

Comparative Example 2

0.89763 g (3.3464 mmol) of diamine monomer (II) was completely dissolved in purified 13 mL of NMP, and the same amount of 1.03812 g (3.3464 mmol) of ODPA was added in a solid state, followed by stirring at room temperature for 12 hours to obtain polyamic acid. Formed. After applying the polyamic acid on a glass plate, the solvent was removed at a temperature of 70 ℃ and vacuum to prepare a film. This was heat treated under an argon stream for 1 hour at 200 ° C to 300 ° C for 1 hour at 300 ° C to obtain a polyimide film. The resulting polyimide had the same chemical structure as that obtained in Example 2, and the physical properties were confirmed to have similar values. However, the polyimide prepared in Comparative Example 1 showed low solubility in organic solvents as compared to the polyimide obtained in Example 2. The remaining solution was stored in a freezer at -20 ° C and part was precipitated in water to obtain a polyamic acid powder.

Comparative Example 3

After using the same compound as in Example 3 to obtain a polyamic acid solution, a polyimide film was obtained through the same heat treatment method as in Comparative Example 1. The resulting polyimide had the same chemical structure as the polyimide obtained in Example 3, and the physical properties thereof were also confirmed to have similar values. However, it showed low solubility in organic solvents as compared to the polyimide obtained from Example 3.

Comparative Example 4

After using the same compound as in Example 4 to obtain a polyamic acid solution, a polyimide film was obtained through the same heat treatment method as in Comparative Example 1. The resulting polyimide had the same chemical structure as the polyimide obtained in Example 4, and the physical properties thereof were also confirmed to have similar values. However, it is not soluble in common organic solvents.

Comparative Example 5

After using the same compound as in Example 5 to obtain a polyamic acid solution, a polyimide film was obtained through the same heat treatment method as in Comparative Example 1. In this case, it was not dissolved in a general organic solvent.

Properties of Polyimide  Tetracarboxylic dianhydride η _inh ^* (dL / g)   Tg (℃)  5% Weight Loss Temperature Airflow Nitrogen CTE (10 ^-6 / ℃)  Example 2      ODPA   0.63   246   565 548    57.1  Example 3      BTDA   0.61   268   539 530    49.7  Example 4      BPDA    -   295   582 561     -  Example 5      PMDA    -    -   545 529     -  Comparative Example 1      ODPA   0.48    -    --     -  Comparative Example 2      ODPA   0.27   254    --    60.5  Comparative Example 3      BTDA   0.45   271    --    50.9  Comparative Example 4      BPDA   0.47   291    --    47.5  Comparative Example 5      PMDA   0.43   346   554 560    56.5

Solubility of Polyimide  NMP  DMAc  DMF DMSO m- cresol  THF  chloroform  Acetone Example 2   ++   ++   ++   ++    ++   ++      ++     - Example 3   ++   ++   ++   ++    ++    +      -     - Example 4    +    +    +    +     +    -      -     - Example 5 + _-    -    -    - + _-    -      -     - Comparative Example 1    -    -    -    -     -    -      -     - Comparative Example 2   ++    +    +    +    ++    -      -     - Comparative Example 3    + + _- + _- + _-     +    -      -     - Comparative Example 4 + _-    -    -    - + _-    -      -     - Comparative Example 5    -    -    -    -     -    -      -     -

* Symbols ++, +, + _-, and-indicating the degree of dissolution in the above table mean that recording is performed well at room temperature _, and recording, partial recording, and melting do not increase when the temperature is increased.

THF in the table means tetrahydrofuran.

As can be seen from the results in Table 2, a polyimide prepared by the process according to Scheme 2 using a diamine monomer in which a trifluoromethyl group is asymmetrically introduced is a monomer of 4,4'-diamino diphenyl ether. The solubility was higher than that in the case of using and prepared through a high temperature heat treatment of 300 ° C.

According to the present invention, a diamine having an asymmetrically introduced trifluoromethyl group, i.e., 2-trifluoro-4,4'-diaminodiphenyl ether, is provided as a monomer of a polyamide, thereby making it possible to obtain several mutual Since the interaction can be suppressed, a polyimide excellent in processability can be produced because the solubility in an organic solvent is sufficient even after the imidation is fully progressed.

In addition, the polyimide according to the present invention is thermoplastic and can maintain the excellent physical properties of the polyimide and is very useful as an electrical, electronic or optical mechanical material material.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (10)

The diamine monomer represented by following General formula (II) and used for manufacture of the polyimide characterized by introduce | transducing a trifluoromethyl group asymmetrically.

2-chloro-5-nitrobenzotrifluoride and 4-nitrophenol are reacted in the presence of a base to prepare a dinitro compound represented by the following structural formula (I); And

Reducing the nitro group in the compound with the dynamite of the above formula (I); Method for producing a diamine monomer represented by the following structural formula (II), characterized in that consisting of steps.

The polyimide produced by imidating the diamine monomer and tetracarboxylic dianhydride monomer of Claim 1, and represented by the following structural formula (V).

Dissolving the diamine monomer and tetracarboxylic dianhydride monomer of claim 1 in an organic solvent to provide a polyamic acid represented by the following structural formula (IV); And

Stirring the polyamic acid to imidize it; Method for producing a polyimide represented by the following structural formula (V), characterized in that consisting of steps.

The method of claim 4, wherein the tetracarboxylic dianhydride is 1,2,4,5, -benzenetetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 2,2 ', 3,3'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-diphenylethercarboxylic acid dianhydride, 2,2'3,3'-diphenyl ether Carboxylic dianhydride, 3,3'-oxyphthalic acid dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2'-3,3'-biphenyltetracarboxylic Acid dianhydride, 3,3 ', 4,4'-tetracarboxylic diphenylsulfide dianhydride, 2,2', 3,3'-tetracarboxylic diphenylsulfide dianhydride, 3,3 ', 4,4 '-Tetracarboxylic diphenyl sulfone dianhydride, 2,2', 3,3'-tetracarboxylic diphenyl sulfone dianhydride, 4,4'-hexafluoroisopropylidene diphthalic anhydride, 1,4,5 , 8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, and 2,3,6,7-naphthalenetetracarboxylic acid At least one is selected from the group which consists of anhydrides, The manufacturing method of the polyimide characterized by the above-mentioned. The diamine monomer according to claim 4, wherein the diamine monomer is 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 2,4'-di Aminodiphenyl ether, 2,2'-diaminodiphenyl ether, 2,3'-diaminodiphenyl ether, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (3-amino Phenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, p-phenylenediamine, m-phenylenediamine, o-phenyl Lendiamine, p-aminobenzylamine, m-aminobenzylamine, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 2 , 2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, bis (4-aminophenyl) sulfide, bis (3- Aminophenyl) sulfide, 3,4-diaminophenylsulfide, bis (4-aminophenyl) sulfoxide, bis (3- Minophenyl) sulfoxide, 3,4-diaminophenyl sulfoxide, bis (4-aminophenyl) sulfone, bis (3-aminophenyl) sulfone, 3,4-diaminophenyl sulfone, 4,4'-diamino Benzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl ] Sulfone, bis [4- (4-aminophenoxy) phenyl] ether, 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy Benzoyl] benzene, 4,4'-bis [3- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4'-bis [3- (3-aminophenoxy) benzoyl] diphenyl ether, 4,4'-bis [4- (4-amino-alpha, alpha-dimethylbenzyl) phenoxy] benzophenone, 4,4'-bis [4- (4-amino-alpha, alpha-dimethylbenzyl) Phenoxy] diphenylsulfone, bis [4- {4- (4-aminophenoxy) phenoxy} phenyl] sulfone, 1,4-bis [4- (4-aminophenoxy) -alpha, alpha-dimethyl Benzyl] benzene, 1,3-bis [4- (4-aminofe C) -alpha, alpha-dimethylbenzyl] benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, and 2 , 2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane mixed with another diamine selected from the group consisting of Method for producing a polyimide, characterized in that the production. The method of claim 4, wherein the reaction by-product is removed by adding a small amount of chlorobenzene to the imidization step. 5. The method of claim 4, wherein the imidization step is stirred at a temperature of 190 ° C. for at least 8 hours. 6.  A film produced by dissolving the polyimide according to any one of claims 4 to 8 in a polar aprotic organic solvent or a phenol solvent. The method of claim 9, wherein the polar aprotic organic solvent is N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), and di The film is selected from the group consisting of methyl sulfoxide (DMSO), and the phenol solvent is m -cresol.

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