KR101772157B1 - Preparation method for polyimide product and the polyimide product thereby - Google Patents

Abstract

The present invention relates to a process for the preparation of a molding composition comprising the steps of: a) injecting or applying a solution of dianhydride and diamine monomer salt or said monomer salt into a molding apparatus; And b) heating and imidizing a solution of the monomer salt or monomer salt to form a polyimide molded article, wherein the method comprises the steps of: preparing a polyimide molded article by mixing the diimide hydride and the diamine It is possible to directly produce a polyimide molded article from a monomer salt or a solution of the monomer salt so that the production step is simple and the cost is reduced and the polyimide molded article produced according to the above- Has a high molecular weight in contrast, and therefore has excellent thermal stability and mechanical properties.

Description

[0001] The present invention relates to a method for producing a polyimide molded article using a salt of a monomer,

The present invention relates to a process for producing a molded article of polyimide using a salt of a monomer.

High heat-resistant polymer materials such as polyimide are indispensable materials for miniaturization, high performance, and high reliability of products due to the development of advanced technology. They are used in the form of films, molded products, fibers, paints, adhesives and composites, / Electronics, automobiles and precision instruments.

Polyimide (PI) among the high heat-resistant polymer materials has excellent mechanical strength, chemical resistance, weather resistance, and heat resistance based on the chemical stability of the imide ring. In addition, it is easy to synthesize, can form a thin film and does not need a crosslinking agent for curing. Due to its excellent electrical properties, it is widely regarded as a highly functional polymer material ranging from microelectronics and optical fields.

The polyimide molded article manufacturing method reported so far is to synthesize polyimide and then inject it into a molding apparatus or apply it to the mold. A typical synthesis method of polyimide is a two-step synthesis method in which polyamic acid (PAA), which is a precursor, is synthesized by reacting dianhydride with diamine, and then imidizing polyamic acid in the next step .

In the first step of the method, the dianhydride is added to the reaction solution in which the diamine is dissolved in the production step of the polyamic acid, and the polyamic acid is produced due to the ring-opening, middle-portion reaction. The reaction solvent to be used is N, N - is a polar organic solvent such as cresol price-dimethylacetamide, N, N-dimethylformamide, N- methylpyrrolidone, meta.

In the second step, the polyamic acid prepared in the first step is imidized by a dehydration and ring-closing reaction through a chemical method or a thermal method. The chemical imidization method is a method in which a chemical dehydrating agent such as acetic anhydride such as acetic anhydride and an imidization catalyst typified by tertiary amines such as pyridine are added to a polyamic acid solution as a precursor and heated at 160 ° C or higher. On the other hand, the thermal imidization method is a method in which a precursor polyamic acid solution is applied to a substrate, the solvent is evaporated, and then heated to 250 to 350 ° C without a chemical dehydrating agent and a catalyst.

As described above, there is a problem in that the production of the polyimide molded product through the conventional polyimide synthesis method has a problem in that it takes a very complicated step to obtain polyimide and a high cost is consumed due to the used dehydrating agent and catalyst. Also, the residual organic solvent may cause problems in the final product.

In order to solve the above problems, there has been developed a method for forming a polyimide molded article at the same time as imidization by injecting or applying a polyamic acid varnish, which is a polyimide precursor, into a molding apparatus. However, in the polyimide molded product thus manufactured, mechanical properties of the molded article itself deteriorate due to a low imidization rate, and a high temperature is required to increase the imidization rate, so that there is a problem that it is difficult to solve the conventional drawbacks.

 Macromolecules 1994, 27, 4101-4105 Kazuo Itoya, Yoshihiro Kumagai, Masa-aki Kakimoto, and Yoshio Imai High-pressure Synthesis of Aliphatic Polyimides via Salt Monomers Composed of Aliphatic Diamines and Oxydiphthalic Acid.

The present invention provides a process for producing a polyimide molded article using a salt of a monomer which makes it possible to simply produce a polyimide molded article including a polyimide film from a solution of a dianhydride and a diamine monomer salt or the above monomer salt.

According to an embodiment of the present invention, there is provided a method of manufacturing a molded article, comprising: a) injecting or applying a solution of a dianhydride and a diamine monomer salt or the monomer salt into a molding apparatus; And b) heating and imidizing the solution of the monomer salt or the monomer salt to form a polyimide molded article.

According to another embodiment of the present invention, there is provided a polyimide molded article produced by the above method, wherein the polyimide molded article has a number average molecular weight of 50,000 to 1,500,000.

According to the present invention, it is possible to directly produce a polyimide molded article from a solution of dianhydride and diamine monomer salt or the monomer salt, so that the manufacturing step is simple and the cost is reduced.

On the other hand, according to the present invention, there is an advantage that both the wholly aromatic polyimide, the partially aliphatic polyimide and the pre-aliphatic polyimide molded article can be produced.

On the other hand, the polyimide molded product manufactured according to the present invention has a higher molecular weight than the polyimide molded product produced by the conventional method, and thus has excellent thermal stability and mechanical properties.

Brief Description of the Drawings Fig. 1 is a graph showing the FT-IR spectrum of 4,4'-oxydiphthalic anhydride and 2,2-bis (3-amino-4-hydroxylphenyl) hexafluoropropane polyimide according to Example 1 of the present invention Lt; / RTI >
FIG. 2 is a graph showing the results of FT (weight average molecular weight) of 3,3 ', 4,4'-benzophenone-tetracarboxylic dianhydride and 4,4'-methylene bis (2-methylcyclohexamine) polyimide according to Example 2 of the present invention -IR spectra.
3 shows FT-IR spectra of cyclobutane-1,2,3,4-tetracarboxylic dianhydride and 4,4'-oxydianiline polyimide according to Example 3 of the present invention.
4 shows FT-IR spectra of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and 4,4'-methylenebis (cyclohexylamine) polyimide according to Example 4 of the present invention will be.
5 shows FT-IR spectra of 4,4'-biphthalic anhydride and 4,4'-oxydianiline polyimide according to Example 5 of the present invention.
FIG. 6 shows FT-IR spectra of the pyrotalic dianhydride and 4,4'-methylene bis (2-methylcyclohexamine) polyimide according to Example 6 of the present invention.
7 shows FT-IR spectra of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and 2,2'-bis (trifluoromethyl) benzidine polyimide according to Example 7 of the present invention .
8 shows FT-IR spectra of cyclobutane-1,2,3,4-tetracarboxylic dianhydride and 4,4'-methylene bis (cyclohexylamine) polyimide according to Example 8 of the present invention will be.
9 shows FT-IR spectra of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and 4,4'-methylenebis (cyclohexylamine) polyamic acid salt according to Comparative Example 1 of the present invention will be.
10 shows FT-IR spectra of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and 4,4'-methylenebis (cyclohexylamine) polyamic acid salt according to Comparative Example 2 of the present invention will be.
11 shows FT-IR spectra of 4,4'-oxydiphthalic anhydride and 4,4'-oxydianiline polyimide according to Comparative Example 3 of the present invention.
12 shows FT-IR spectra of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and 4,4'-methylenebis (cyclohexylamine) polyimide according to Comparative Example 4 of the present invention will be.

The present invention relates to a process for producing a polyimide molded article using a salt of a monomer which makes it possible to simply produce a polyimide molded article including a polyimide film from a solution of a dianhydride and a diamine monomer salt or the above monomer salt.

According to the polyimide molded article manufacturing method, since the polyimide molded article can be directly manufactured from the solution of the dianhydride and the diamine monomer salt or the monomer salt, the manufacturing step is simple and the cost is reduced. Further, according to the present invention, there is an advantage that both the wholly aromatic polyimide, the partially aliphatic polyimide and the pre-aliphatic polyimide molded article can be produced. On the other hand, the polyimide molded product manufactured according to the present invention has a higher molecular weight than the polyimide molded product produced by the conventional method, and thus has excellent thermal stability and mechanical properties.

Hereinafter, the present invention will be described in more detail.

Production of molded polyimide

In one embodiment to accomplish the object of the present invention, there is provided a process for the preparation of a composition comprising: a) injecting or applying a solution of a dianhydride and a diamine monomer salt or a monomer salt into a molding apparatus; And b) heating and imidizing the monomer salt or monomer salt solution to form a polyimide molded article.

First, a solution of dianhydride and diamine monomer salt or a solution of said monomer salt is injected or applied to the molding apparatus (step a).

In one embodiment of the present invention, the dianhydride may be substituted or unsubstituted at least one dianhydride, and the dianhydride may be aromatic or aliphatic.

Meanwhile, in one embodiment of the present invention, the dianhydride may be a dianhydride represented by the following formula (1).

≪ Formula 1 >

(R ₁ in the formula 1 is a compound of the following

. ≪ / RTI >

In one embodiment of the present invention, the diamine may be substituted or unsubstituted at least one diamine, and the diamine may be aromatic or aliphatic.

Meanwhile, in one embodiment of the present invention, the diamine may be a diamine of the following formula (2).

(2)

(Wherein R < 2 _> represents the following compound

≪ / RTI > X is an integer satisfying 1? X? 50, n is a natural number in the range of 1 to 20, W, X and Y are each an alkyl or aryl group having 1 to 30 carbon atoms, and Z is an ester group , An amide group, an imide group and an ether group.

On the other hand, the solvent of the monomer salt solution in which the monomer salt is dissolved in step a) may be water or organic solvent.

In one embodiment of the present invention, the water may be at least one selected from the group consisting of distilled water, deionized water and tap water.

In one embodiment of the present invention, the organic solvent is selected from the group consisting of N -methyl-2-pyrrolidone, N, N -dimethylacetamide, N, N -dimethylformamide, N -vinylpyrrolidone, N -Methyl caprolactam, dimethyl sulfoxide, tetramethyl urea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, meta-cresol, gamma-butyrolactone, ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol , Ethyl carbitol acetate, butyl carbitol acetate, ethylene glycol, ethyl lactate, butyl lactate, cyclohexanone, cyclopentanone, hexane (normalhexane, isohexane, cyclohexane), pentane, heptane, benzene, toluene, , Methanol, ethanol, propanol (normal propanol, isopropanol), butanol (normal-, iso-, tertiary-), cyclohexanol, octanol, benzyl alcohol, acetone, methyl ethyl ketone, methyl butyl ketone, Ethyl, diethyl ether, isopropyl ether, tetrahydrofuran A single solvent selected from the group consisting of furan, chloroform, dioxane, diethylformamide, sulfolane, formic acid, acetic acid, propionic acid, acetonitrile and tetralin or a mixture of two or more thereof.

The molding apparatus for injecting or applying a solution of the monomer salt or the monomer salt may be a device commonly used in the art and may be varied depending on the kind of the desired molded article and should be able to simultaneously perform the imidization reaction .

Next, when the solution of the monomer salt or the monomer salt injected or applied to the molding apparatus is heated, a polyimide molded article is produced simultaneously with the imidation (step b).

Meanwhile, the step b) may be carried out by heating to a temperature in the range of 150 to 450 ° C, more specifically, in a temperature range of 200 to 400 ° C. If the temperature in the step b) is lower than 150 ° C, the imidization reaction does not proceed. If the temperature is higher than 450 ° C, thermal decomposition of the monomer or the polymer itself may occur.

On the other hand, the step b) may be carried out under a pressure condition of more than 0 but less than 1000 bar. More specifically, in a pressure condition of more than 0 to 500 bar. If a pressure of 1000 bar or more is applied in the step b), the molding apparatus (reaction vessel) may be damaged.

On the other hand, the step b) may be carried out for 10 minutes to 3 days. More specifically, the reaction may proceed for 1 hour to 48 hours. If the reaction time is less than 10 minutes, the reaction does not proceed well. If the reaction time exceeds 3 days, the process cost may be excessively increased.

In one embodiment of the present invention, the monomer salt or monomer salt solution injected or applied into the molding apparatus of the step b) includes a group consisting of heat treatment, hot air treatment, corona treatment, high frequency treatment, ultraviolet ray treatment, To heat the imidization reaction.

On the other hand, in an embodiment of the present invention, film processing including melt processing, hollow processing, calendering and sintering simultaneously with the imidization reaction of step b) Casting, lamination, compression molding, injection molding, blow molding, rotary molding, thermoforming and slush molding; And fiber processing including wet spinning, dry spinning, and melt spinning to produce a polyimide molded article.

On the other hand, in one embodiment of the present invention, the polyimide molded product produced is a polyimide film comprising a polyimide film, a high heat resistant engineering plastic, an adhesive, a tape, a fiber, a liquid crystal alignment film, an interlayer insulator, a coating film resin, Lt; / RTI > may be used in one or more applications selected from the group.

The polyimide molded product produced according to the production method of the present invention as described above has a high molecular weight as compared with the polyimide molded product produced by the conventional method, and thus has excellent thermal stability and mechanical properties. The polyimide molded article can be used in a wide variety of industrial fields such as space, aviation, electric / electronic, semiconductor, transparent / flexible display, liquid crystal alignment film, automobile, precision instrument, packaging, medical material, separator, fuel cell, .

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples. It should be understood, however, that the following examples and experimental examples are provided to aid understanding of the present invention and are not intended to limit the scope of the present invention thereto.

Example

Example 1: Production of wholly aromatic polyimide molded article

5 g of the monomer salt obtained through the reaction of 4,4'-oxydiphthalic anhydride with 2,2-bis (3-amino-4-hydroxylphenyl) hexafluoropropane was placed in a compression molding vessel, Imidization and simultaneous aromatic polyimide molding were made for 8 hours.

In the infrared absorption spectrum (Fig. 1) of the synthesized polymers 1783cm ^-1 and 1709cm ^- 1 already in C = O absorption band of in deugi, 1381cm ^-1 The absorption band of CN already deugi was observed.

Example 2: Production of partially aliphatic polyimide molded article

5 g of a monomer salt of 3,3 ', 4,4'-benzophenone-tetracarboxylic dianhydride and 4,4'-methylenebis (2-methylcyclohexamine) was dissolved in 15 g of ethanol to prepare a 20 wt% monomer salt solution .

Next, the monomer salt solution was spin-coated on soda glass and heated at 250 ° C for 24 hours under atmospheric conditions to prepare a partially aliphatic polyimide film.

In the infrared absorption spectrum (Fig. 2) of the synthetic polymer 1780cm ^-1 and 1703cm ^- 1 already in C = O absorption band of in deugi, 1379cm ^-1 The absorption band of CN already deugi was observed.

Example 3: Preparation of partial aliphatic polyimide

5 g of the monomer salt obtained through the reaction of cyclobutane-1,2,3,4-tetracarboxylic dianhydride with 4,4'-oxydianiline was placed in a compression molding vessel and imidized at 250 ° C. for 24 hours A partially aliphatic polyimide molded article was produced.

In the infrared absorption spectrum of the synthesized polymer (Fig. 3) 1780cm ^-1 and 1712cm ^- 1 already in C = O absorption band of in deugi, 1379cm ^-1 The absorption band of CN already deugi was observed.

Example 4: Preparation of all aliphatic polyimide

20 g of a 25 wt% monomer salt solution obtained through the reaction of 2.242 g (0.01 mol) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride with 4,4'-methylenebis (cyclohexylamine) And then heated at 400 < 0 > C for 18 hours under atmospheric conditions to prepare a wholly aliphatic polyimide film.

In the infrared absorption spectrum of the synthesized polymer (Fig. 4) 1785cm ^-1 and 1707cm ^- 1 already in C = O absorption band of in deugi, 1380cm ^-1 The absorption band of CN already deugi was observed.

Example 5: Preparation of wholly aromatic polyimide

5 g of the monomer salt obtained through the reaction of 4,4 '- (biphthalic anhydride) and 4,4'-oxydianiline was placed in a compression molding vessel and imidized at 350 ° C. for 6 hours to obtain a wholly aromatic polyimide A molded article was prepared.

In the infrared absorption spectrum (Fig. 5) of the synthesized polymers 1785cm ^-1 and 1711cm ^- 1 already in C = O absorption band of in deugi, 1379cm ^-1 The absorption band of CN already deugi was observed.

Example 6: Preparation of partial aliphatic polyimide

5 g of the monomer salt obtained through the reaction of 4,4'-methylenebis (2-methylcyclohexamine) with pyrotalic dicarboxylic acid dihydride was placed in a compression molding vessel and imidized at 350 ° C. for 12 hours to obtain a partially aliphatic polyimide molded article .

In the infrared absorption spectrum of the synthesized polymer (FIG. 6) 1785cm ^-1 and 1709cm ^- 1 already in C = O absorption band of in deugi, 1388cm ^-1 The absorption band of CN already deugi was observed.

Example 7: Preparation of partial aliphatic polyimide

20 g of a 25 wt% monomer salt solution obtained by reacting 1,2,4,5-cyclohexanetetracarboxylic dianhydride with 2,2'-bis (trifluoromethyl) benzidine was spin-coated on a soda glass Followed by heating at 300 DEG C for 24 hours to prepare a partially aliphatic polyimide film.

In the infrared absorption spectrum of the synthesized polymer (Fig. 7) 1779cm ^-1 and 1711cm ^- 1 already in C = O absorption band of in deugi, 1383cm ^-1 The absorption band of CN already deugi was observed.

Example 8: Preparation of all aliphatic polyimide

5 g of a monomer salt of cyclobutane-1,2,3,4-tetracarboxylic dianhydride and 4,4'-methylenebis (cyclohexylamine) was dissolved in 15 g of distilled water to synthesize a 20 wt% monomer salt solution.

Next, the salt solution was spin-coated on soda glass and heated at 280 DEG C for 24 hours to prepare a pre-aliphatic polyimide film.

In the infrared absorption spectrum (Fig. 8) of the synthesized polymers 1779cm ^-1 and 1713cm ^- 1 already in C = O absorption band of in deugi, 1371cm ^-1 The absorption band of CN already deugi was observed.

Comparative Example 1: Production of preformed aliphatic polyimide

5 g of a monomer salt of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and 4,4'-methylenebis (cyclohexylamine) was placed in a compression molding vessel and the reaction was carried out at 150 ° C. for 1 minute. The production reaction did not proceed sufficiently and a molded product of all aliphatic polyimide could not be produced.

In the infrared absorption spectrum (FIG. 9) of the synthesized polymer, the C = O absorption band of the imide group at 1787 cm ^-1 , which can be confirmed by typical polyimide, was not observed.

Comparative Example 2: Production of preformed aliphatic polyimide

5 g of a monomer salt of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and 4,4'-methylenebis (cyclohexylamine) was dissolved in 20 g of distilled water to obtain a monomer salt solution.

Next, the solution was reacted at 80 ° C. for 24 hours using a vacuum oven, but the polyimide-forming reaction did not proceed sufficiently, so that a pre-aliphatic polyimide film could not be produced.

In the infrared absorption spectrum (FIG. 11) of the synthesized polymer, the C = O absorption band of the imide group at 1787 cm ^-1 , which can be confirmed by typical polyimide, was not observed.

Comparative Example 3: Preparation of wholly aromatic polyimide

45 mL of N-methyl-2-pyrrolidone was added to a 100-mL 2-neck round bottom flask substituted with nitrogen gas, and 3.102 g (0.01 mol) of 4,4'-oxydiphthalic anhydride and 4,4'- (0.01 mol) of oxydianiline were added and reacted at 25 DEG C for 24 hours to synthesize polyamic acid.

The mixture was then reprecipitated using water. After gravity filtration, it was washed with 100 mL of water and 100 mL of methanol, followed by vacuum drying to obtain a dried polyamic acid.

Next, 5 g of the polyamic acid was dissolved in 15 g of N-methyl-2-pyrrolidone to synthesize a polyamic acid solution.

Next, the polyamic acid solution was spin-coated on soda glass and heated at 350 캜 for 24 hours under atmospheric conditions to prepare a wholly aromatic polyimide film.

In the infrared absorption spectrum (Fig. 11) of the synthetic polymer and 1788cm ^-1 1709cm ^-1 C = O absorption band of the already deugi in, 1388cm ^-1 The absorption band of CN already deugi was observed.

Comparative Example 4: Preparation of all aliphatic polyimide

N-methyl-2-pyrrolidone (40 mL) was added to a 100-mL 2-neck round bottom flask substituted with nitrogen gas, and 2.242 g (0.01 mol) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride And 2.002 g (0.01 mol) of 4,4'-methylenebis (cyclohexylamine) were added thereto, and reacted at 25 ° C for 24 hours to synthesize polyamic acid.

The mixture was then reprecipitated using water. After gravity filtration, it was washed with 100 mL of water and 100 mL of methanol, followed by vacuum drying to obtain a dried polyamic acid.

As a chemical imidization method, polyamic acid was dissolved in N-methyl-2-pyrrolidone, and 5 mL of acetic anhydride and 3 mL of pyridine were added to the solution, refluxed at 170 DEG C for 5 hours, and then cooled to room temperature Re-precipitation was carried out using an excess of ice water. After washing with 100 mL of water and 100 mL of methyl alcohol, the mixture was vacuum-dried to synthesize all aliphatic polyimide.

As a thermal imidation method, the dried polyamic acid was heated at 250 to 300 ° C in an oven or a hot plate stepwise and heated for 12 hours to obtain a pre-aliphatic polyimide.

Next, 5 g of the polyimide was dissolved in 15 g of N-methyl-2-pyrrolidone to obtain a polyimide solution.

Next, the polyimide solution was spin-coated on soda glass and heated at 200 ° C for 24 hours under atmospheric conditions to produce a wholly aliphatic polyimide film, but cracking occurred.

In the infrared absorption spectrum (Fig. 12) of the synthetic polymer and 1781cm ^-1 1714cm ^-1 C = O absorption band of the already deugi in, 1379cm ^-1 The absorption band of CN already deugi was observed.

As can be seen in Table 1, in Examples 1 to 8, a molded article was prepared by imidization in the temperature range of 180 to 400 ° C for 8 to 24 hours using a monomer salt or a salt solution. As shown in the above example, it is possible to manufacture a polyimide molded article in a reduced manufacturing step as compared with the conventional method of producing a polyimide molded article, and it has been confirmed that the polyimide molded article has a high molecular weight.

On the other hand, in Comparative Example 1 and Comparative Example 2, the salt or salt solution obtained through the reaction of the monomer salt was subjected to compression molding and film processing at a temperature of less than 150 ° C or in a time of less than 1 minute, but a polyimide molded article I could not. In Comparative Example 3, a polyamic acid precursor was obtained using an organic solvent and then film-processed at 350 ° C. for 24 hours. However, it was confirmed that the polyimide precursor was lower in molecular weight than the polyimide obtained in Examples 1 to 8. In Comparative Example 4, a polyimide was obtained by performing a conventional method of synthesizing a polyamic acid precursor by using an organic solvent to produce a polyimide, and then film processing was performed at 200 ° C. for 24 hours. However, It was confirmed that the molecular weight of the polyimide obtained in Example 8 was lower than that of the polyimide.

Claims (10)

a) injecting a solid substituted or unsubstituted at least one dianhydride and at least one substituted or unsubstituted diamine monomer salt into a molding apparatus; And
b) heating the monomer salt to a temperature in the range of 150 to 450 캜 to imidize and form the polyimide molded product,
Wherein the polyimide molded article has a number average molecular weight of 50,000 to 1,500,000. The method according to claim 1,
Wherein the dianhydride is an aromatic or aliphatic dianhydride. 3. The method of claim 2,
Wherein the dianhydride is a dianhydride represented by the following formula (1): < EMI ID =

&Lt; Formula 1 &gt;
(R ₁ in the formula 1 is a compound of the following

&Lt; / RTI &gt; The method according to claim 1,
Wherein the diamine is an aromatic or aliphatic diamine. 5. The method of claim 4,
Wherein the diamine is a diamine of the following formula (2): < EMI ID =

(2)
(Wherein R &lt; 2 _&gt; represents the following compound

&Lt; / RTI &gt; X is an integer satisfying 1? X? 50, n is a natural number in the range of 1 to 20, W, X and Y are each an alkyl or aryl group having 1 to 30 carbon atoms, and Z is an ester group , An amide group, an imide group and an ether group). delete The method according to claim 1,
Wherein the step b) is carried out under a pressure condition of more than 0 but less than 1000 bar. The method according to claim 1,
Wherein the step b) is performed for 10 minutes to 3 days. The method according to claim 1,
In the step b), the monomer salt is imidized by heating by one or more treatment methods selected from the group consisting of heat treatment, hot air treatment, corona treatment, high frequency treatment, ultraviolet ray treatment, infrared ray treatment and laser treatment. The method according to claim 1,
In the step b), the monomer salt is imidized,
Film processing selected from the group consisting of melt processing, hollow processing, calendering and sintering;
A molding process selected from the group consisting of casting, lamination, compression molding, injection molding, blow molding, rotary molding, thermoforming and slush molding; And
A fiber spinning process, a spinning process, a wet spinning process, a dry spinning process and a fiber spinning process including melt spinning.

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