KR20170086455A - Preparation method of polyimide film, and the polyimide film thereby - Google Patents

Abstract

The present invention relates to a process for producing a polyimide film by colorless and transparent polyimide by imidizing the polyamic acid solution at a relatively low temperature and then using the polyimide to form a polyimide film which is colorless and transparent as well as flexible and can be used for display purposes The present invention relates to a process for producing a polyimide film and a polyimide film produced by the process, which comprises the steps of: (a) preparing a solution of polyamic acid by adding dianhydride and diamine into a solvent, step; (b) adding a chemical dehydrating agent and a catalyst to the prepared polyamic acid solution; (c) preparing a polyimide solution by imidizing the polyamic acid solution at 20 to 80 캜; (d) applying the prepared polyimide solution to a substrate; And (e) drying the applied polyimide solution to produce a polyimide film; .

Description

The present invention relates to a method for producing a polyimide film, and a preparation method of the polyimide film,

The present invention relates to a process for producing a polyimide film and a polyimide film produced thereby.

High heat-resistant polymer materials are essential materials for miniaturization, high performance, and high reliability of products in accordance with the development of advanced technology. They are used in the form of film, molded product, fiber, paint, adhesive and composite materials. And precision instruments.

Among them, films have been developed as electronic materials and packaging materials. These types of films are general-purpose engineering plastic films mainly composed of polyester films, and have excellent heat resistance, chemical resistance, and electrical properties. A polyimide (PI) film, an aramid film having high elasticity properties, a fluorine film, and a super engineering thermoplastic film, and they can be classified into special films for various purposes depending on their heat resistance and applications. The use of these materials is steadily increasing with the development of the IT industry.

Among these materials, the polyimide 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 film, and has the advantage of not requiring a crosslinking agent for curing. In addition, due to its excellent electrical properties, it is attracting attention as a highly functional polymer material ranging from microelectronics and optical fields.

In recent years, weight reduction and miniaturization of products have been emphasized in the field of display, but currently used glass substrates are heavy and broken, and continuous process is difficult. For this reason, studies are underway to utilize a polyimide substrate, which has advantages of being light, flexible, and continuous process in place of a glass substrate, in the production of a flexible display.

The general synthesis method of polyimide is composed of two steps of synthesizing the precursor polyamic acid by the reaction of dianhydride and diamine and then imidizing the polyamic acid in the next step. The synthesis of the polyamic acid is a process in which a diamine and a dianhydride dissolved in a solvent are opened to produce a polyamic acid by the action of a middle part, and the reaction solvent used is N, N -dimethylacetamide, N, Polar organic solvents such as methyl formamide, N -methyl-2-pyrrolidone, and meta-cresol are predominant. On the other hand, the synthesized polyamic acid is imidized by a dehydration and ring-closing reaction through a chemical method or a thermal method to produce a polyimide.

The chemical imidization method is a method in which a chemical dehydrating agent represented by an acid anhydride such as acetic anhydride and an imidation catalyst represented by a tertiary amine 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 polyamic acid solution as a precursor is applied to a substrate, the solvent is evaporated, and the film is thermally imidized by heating to 250 to 350 ° C without a chemical dehydrating agent and a catalyst.

The polyimide prepared through the conventional polyamic acid imidization reaction as described above and the film containing the same tend to be yellow to brown, and have insufficient solubility and flexibility to be used for display purposes. Therefore, in order to improve colorlessness, transparency and solubility of polyimide, a compound having a structure containing a fluorine group or an aliphatic structure as a dianhydride or a diamine compound has been used in the prior art. However, even in such a case, it has been difficult to produce polyimide having colorlessness and transparency enough to be used for display purposes.

Korean Patent Publication No. 10-2007-0116395 (December 10, 2007)

The inventors of the present invention have found that the polyimide synthesized by the conventional technique exhibits low transparency and solubility as well as coloration and has a great influence on the imidization reaction at a high temperature of 160 to 350 ° C.

Accordingly, the present invention provides a method for producing a colorless transparent polyimide film by imidizing polyamic acid at a relatively low temperature in order to solve the above problems.

According to an embodiment of the present invention, there is provided a method of manufacturing a polyamic acid solution, comprising: (a) preparing a solution of polyamic acid by adding dianhydride and diamine in a solvent; (b) adding a chemical dehydrating agent and a catalyst to the prepared polyamic acid solution; (c) preparing a polyimide solution by imidizing the polyamic acid solution at 20 to 80 캜; (d) applying the prepared polyimide solution to a substrate; And (e) drying the applied polyimide solution to produce a polyimide film; And a method for producing the polyimide film.

In another embodiment of the present invention, there is provided a polyimide film produced by the above method, wherein the polyimide film has a Yellow Index of 5 or less.

In another embodiment of the present invention, there is provided a polyimide film produced by the above method, wherein the polyimide film exhibits a light transmittance of 90% or more with respect to light having a wavelength of 450 nm at a thickness of 20 탆 .

Further, in another embodiment of the present invention, there is provided a display comprising the polyimide film.

The polyimide film produced according to the process for producing a polyimide film according to the present invention is colorless, transparent and excellent in solubility in an organic solvent, unlike the polyimide film produced according to the prior art.

In addition, the polyimide film is not only colorless and transparent but also flexible and can be used for display purposes.

1 shows the FT-IR spectrum of 4,4'-oxydiphthalic anhydride and 2,2-bis (4-aminophenyl) hexafluoropropane polyimide according to Example 1 and Example 2 of the present invention Lt; / RTI >
2 is a graph showing the FT-IR spectrum of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and 4,4'-diaminodiphenylmethane polyimide according to Example 3 and Example 4 of the present invention. Lt; / RTI >
3 shows FT-IR spectra of pyromellitic dianhydride and 4,4'-methylene bis (cyclohexylamine) polyimide according to Example 5 and Example 6 of the present invention.
4 shows FT-IR spectra of 1,2,3,4-cyclopentane tetracarboxylic dianhydride and 1,4-diaminocyclohexane polyimide according to Example 7 and Example 8 of the present invention will be.
FIG. 5 is a graph showing the relationship between the content of 1,2,3,4-cyclobutane tetracarboxylic dianhydride and 3,3 ', 4,4'-benzopinone tetracarboxylic dianhydride and 2,2- FT-IR spectrum of bis (4-aminophenyl) hexafluoropropane polyimide.
Fig. 6 is a graph showing the UV-vis spectra of 4,4'-oxydiphthalic anhydride and 2,2-bis (4-aminophenyl) hexafluoropropane polyimide film according to Example 1 and Example 2 of the present invention. Transmission spectrum.
7 is a graph showing the results of measurement of UV-vis spectra of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and 4,4'-diaminodiphenylmethane polyimide film according to Example 3 and Example 4 of the present invention, vis transmission spectrum.
8 is a UV-vis transmission spectrum of pyromellitic dianhydride and 4,4'-methylene bis (cyclohexylamine) polyimide film according to Example 5 and Example 6 of the present invention.
9 shows the UV-vis transmission spectrum of 1,2,3,4-cyclopentane tetracarboxylic dianhydride and 1,4-diaminocyclohexane polyimide film according to Example 7 and Example 8 of the present invention to be.
FIG. 10 is a graph showing the results obtained by comparing the content of 1,2,3,4-cyclobutane tetracarboxylic dianhydride and 3,3 ', 4,4'-benzopinone tetracarboxylic dianhydride and 2,2- UV-vis transmission spectrum of bis (4-aminophenyl) hexafluoropropane polyimide film.
11 is a photograph of a polyimide film according to Examples 1 to 8, Comparative Example 1 and Comparative Example 2.

The present invention relates to a method for producing a polyimide film by preparing a polyimide solution by imidizing a polyamic acid synthesized from a dianhydride compound and a diamine compound at a relatively low temperature condition.

The polyimide film produced by the above method is colorless, transparent, and excellent in flexibility, and is suitable for use in a display.

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

Production of polyimide film

(A) preparing a polyamic acid solution by adding dianhydride and diamine in a solvent and stirring the mixture; (b) adding a chemical dehydrating agent and a catalyst to the prepared polyamic acid solution; (c) preparing a polyimide solution by imidizing the polyamic acid solution at 20 to 80 캜; (d) applying the prepared polyimide solution to a substrate; And (e) drying the applied polyimide solution to produce a polyimide film; And a method for producing the polyimide film.

In another embodiment of the present invention, the polyamic acid solution prepared in step (a) is subjected to re-precipitation, filtration and drying in order to prepare a polyamic acid powder, and the polyamic acid powder is dissolved in a solvent to form a polyamic acid And the step (b) may be further carried out.

In another embodiment of the present invention, the polyimide powder is prepared by sequentially repeating the steps of reprecipitating, filtering and drying the polyimide solution prepared in the step (c), dissolving the polyimide powder in a solvent, And then proceeding to step (d).

First, dianhydride and diamine are added to a solvent and stirred to prepare a polyamic acid solution (step a).

The polyamic acid may be a polyimide precursor which is synthesized from a reaction between one or more substituted or unsubstituted dianhydrides and one or more substituted or unsubstituted diamines.

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

Meanwhile, in one embodiment of the present invention, the dianhydride may include a compound 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 substituted or unsubstituted diamines may be aromatic or aliphatic diamines.

Meanwhile, in one embodiment of the present invention, the diamine may include a compound represented by the following formula (2).

(2)

(Wherein R < 2 _> represents the following compound

. ≪ / RTI >

On the other hand, a solvent for preparing a polyamic acid solution by reacting the dianhydride with diamine; A solvent in which the polyamic acid powder is dissolved; And a solvent to which the polyimide powder may be dissolved in an organic daily, for example, N - methyl-2-pyrrolidone, N, N - dimethyl acetamide, N, N - dimethyl-formamide, N - vinyl But are not limited to, pyrrolidone, N -methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide, meta-cresol, gamma-butyrolactone, ethylcellosolve, Butanol, cyclohexane, hexane, hexane, heptane, cyclohexane, cyclohexanone, cyclohexanone, cyclohexanone, cyclohexanone, cyclohexane, , Butanol (normal-, iso-, tertiary-), cyclohexanol, octanol, benzyl alcohol, acetone, methyl ethyl ketone, methyl butyl ketone , Methyl acetate, ethyl acetate, diethyl ether, iso One single solvent selected from the group consisting of propyl ether, tetrahydrofuran, chloroform, dioxane, diethylformamide, sulfolane, formic acid, acetic acid, propionic acid, acetonitrile and tetralin or a mixture of two or more It can be used every day.

In one embodiment of the present invention, the step (a) may be carried out at a reaction temperature of 0 to 30 ° C. If the reaction temperature is less than 0 ° C, the reaction rate is low, which may interfere with the polyimide production process. If the reaction temperature is more than 30 ° C, the reaction temperature may rapidly increase due to the exothermic reaction due to the production of polyamic acid.

In one embodiment of the present invention, the step (a) may be carried out for 1 to 48 hours, more specifically 6 to 36 hours. If the reaction time is less than 1 hour, the polymerization reaction may not proceed sufficiently and the molecular weight may be too low, and after 48 hours, gelation of the polyamic acid may occur.

In an embodiment of the present invention, the polyamic acid solution prepared after the reaction may be further subjected to a re-precipitation, filtration and drying process. The polyamic acid powder prepared after drying may be dissolved in a solvent and then be made into a polyamic acid solution.

The solvent used in the reprecipitation and filtration is, for example, water, methanol, ethanol, isopropanol, n-butanol, n-hexane, acetone, ether, ethyl acetate, tetrahydrofuran and chloroform It may be one single solvent selected or two or more mixing days.

Meanwhile, the drying process may be performed at a temperature ranging from 20 to 80 ° C, more specifically, at a temperature ranging from 30 to 80 ° C, and more specifically, a temperature range of 40 to 60 ° C. If the drying temperature is lower than 20 ° C, it takes a long time to dry and the used solvent may remain. If the drying temperature exceeds 80 ° C, the color of the polyimide may become dark.

On the other hand, the drying process may be performed at a pressure of 1 atm (1013 hPa) or less, more specifically, at a pressure of 0.9 to 0.001 atmospheres (910 hPa to 1 hPa), more specifically 0.7 to 0.01 atmospheres (710 hPa to 10 hPa) Lt; / RTI >

Next, a chemical dehydrating agent and a catalyst are added to the polyamic acid solution (step b).

The chemical dehydrating agent and the catalyst are for carrying out the imidization reaction in the polyamic acid solution.

The chemical dehydrating agent may be one or more selected from the group consisting of acetic anhydride, anhydrous propionic acid, anhydrous butyric acid, anhydrous benzoic acid, anhydrous adipic acid, anhydrous isophthalic acid, phthalic anhydride and trimellitic anhydride. have.

On the other hand, the catalyst is trimethyl amine, triethyl amine, methyl-pyrrolidine, N, N - dimethyl-cyclohexyl amine, imidazole, 1,2-dimethyl-imidazole, N - methylimidazole, N - benzyl Methylimidazole, 2-methylimidazole, N -benzyl-2-methylimidazole, isoquinoline, 3,5 May be one or more selected from the group consisting of dimethylpyridine, 3,4-dimethylpyridine, 2,5-dimethylpyridine, 2,4-dimethylpyridine and 4-n-propylpyridine.

In one embodiment of the present invention, the chemical dehydrating agent and the catalyst each have a molar ratio of the same to 50 times the polyamic acid repeating unit, specifically 2 to 40 times, more specifically 5 to 30 times Can be added. When the amounts of the chemical dehydrating agent and the catalyst are less than 1 times the molar ratio of the polyamic acid repeating units, the reaction rate is so low that the imidization reaction can not proceed sufficiently, There is a problem that the physical properties of the polyimide deteriorate due to the residual dehydrating agent and the catalyst.

Next, the polyimide solution dissolved in the solvent is imidized at 20 to 80 캜 to prepare a polyimide solution (step c).

In the prior art, the reaction proceeded at a relatively high temperature of 160 to 350 DEG C in the imidization reaction of the polyamic acid. In this case, the polyimide film prepared using the polyimide produced was yellow or brown, There is a problem that it is difficult to apply.

On the other hand, in the present invention, there is an advantage that a colorless transparent polyimide film can be obtained when the polyimide film is produced by proceeding the imidization reaction of the polyamic acid at a relatively low temperature as compared with the conventional technique.

In order to realize a colorless and transparent polyimide film as described above, the imidization reaction may be carried out at a temperature of 20 to 80 ° C, and more specifically, at a temperature of 25 to 60 ° C.

If the imidization reaction temperature of the polyamic acid is less than 20 캜, the imidization reaction rate becomes too slow, so that the imidization reaction can not proceed sufficiently and polyimide production is difficult. When the reaction temperature exceeds 80 ° C, the finally prepared polyimide film exhibits a light transmittance of 90% or less with respect to light having a wavelength of 450 nm at a thickness of 20 μm, and the Yellow Index increases to 10 or more Which makes it unsuitable for use as a display.

In one embodiment of the present invention, the imidization reaction may be carried out for 10 minutes to 72 hours, in particular 6 to 48 hours, more particularly 12 to 24 hours. If the reaction time is less than 10 minutes, the imidization reaction does not progress well, and if the reaction time exceeds 72 hours, gelation may proceed.

Next, the polyimide solution prepared through the series of steps is applied to the substrate (step d).

In one embodiment of the present invention, the polyimide solution prepared through step (c) may be directly applied to a substrate to produce a polyimide film.

Meanwhile, in another embodiment of the present invention, the polyimide solution prepared through the step (c) is re-precipitated, filtered and dried, and then the polyimide powder obtained by the drying is dissolved in a solvent to prepare a polyimide solution And the polyimide solution may be applied to a substrate to produce a polyimide film.

The solvent used in the reprecipitation and filtration is, for example, water, methanol, ethanol, isopropanol, n-butanol, n-hexane, acetone, ether, ethyl acetate, tetrahydrofuran and chloroform May be selected from a single solvent or a mixture of two or more solvents.

Meanwhile, the drying process may be performed at a temperature ranging from 20 to 80 ° C, more specifically, at a temperature ranging from 30 to 80 ° C, and more specifically, a temperature range of 40 to 60 ° C. If the drying temperature is lower than 20 ° C, it takes a long time to dry and the used solvent may remain. If the drying temperature exceeds 80 ° C, the color of the polyimide may become dark.

On the other hand, the drying process may be performed at a pressure of 1 atm (1013 hPa) or less, more specifically, at a pressure of 0.9 to 0.001 atmospheres (910 hPa to 1 hPa), more specifically 0.7 to 0.01 atmospheres (710 hPa to 10 hPa) Lt; / RTI > If necessary, additives such as a wettability improver may be added to the polyimide solution. In this case, the additive may be added in an amount of 0.001 to 5 wt% relative to the total weight of the polyimide solution, more specifically 0.01 to 2 wt% Lt; / RTI >

The solvent for dissolving the polyimide powder may include N -methyl-2-pyrrolidone (NMP), 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, tetra One or more solvents selected from the group consisting of chloroform, chloroform, dioxane, diethylformamide, sulfolane, formic acid, acetic acid, propionic acid, acetonitrile and tetralin can be used.

On the other hand, the polyimide is dissolved in an amount of 1 to 90 wt% based on the total weight of the polyimide solution to be produced.

Meanwhile, in the above process, for example, a spin coating method, a dipping method, a flexographic printing method, an inkjet printing method, a spraying method, a potting method, a screen printing method and the like can be used. In order to obtain a thick film having a thickness of 10 탆 or more among these methods, a bar coating method, a slit coating method, a screen printing method, a spin coating method, or the like may be used.

Next, the polyimide film is prepared by evaporating the solvent of the polyimide solution applied to the substrate (step e).

In one embodiment of the present invention, the polyimide film is prepared by evaporating the solvent at 20 to 100 DEG C in the applied polyimide solution. More specifically, the solvent is evaporated at 25 to 60 占 폚. If the evaporation temperature of the solvent is less than 20 캜, the evaporation time of the solvent is excessively long, and if it is 100 캜 or more, the polyimide may be colored.

The step of evaporating the solvent preferably proceeds at 1 atm or less.

The polyimide film is produced through the above-described series of processes. The polyimide film produced according to the present invention is colorless, transparent and flexible. In particular, the yellow index of the polyimide film is 5 or less, and the light transmittance is 90% or more with respect to light having a wavelength of 450 nm at a thickness of 20 탆. The polyimide of the polyimide film may be a wholly aromatic polyimide, a partially aliphatic polyimide, or a prealiphatic polyimide.

Meanwhile, the polyimide film produced according to the present invention can be applied to various fields such as space, aviation, electric / electronic, semiconductor, transparent / flexible display, liquid crystal alignment film, automobile, precision instrument, packaging, , Secondary batteries, and the like.

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

Example

Example 1: Preparation of wholly aromatic polyimide film

184 mL of N -methyl-2-pyrrolidone (NMP) was added to a 500-mL two-necked round bottom flask substituted with nitrogen gas, and 15.510 g (0.05 mol) of 4,4'-oxydiphthalic anhydride and 2 And 16.713 g (0.05 mol) of 2-bis (4-aminophenyl) hexafluoropropane were added thereto, followed by reaction at 0 to 25 ° C for 24 hours to synthesize polyamic acid.

Next, 25.522 g (0.25 mol) of acetic anhydride and 19.775 g (0.25 mol) of pyridine were added to the solution, and the mixture was stirred at 20 ° C for 24 hours, Reprecipitated. After filtration, the filtrate was washed with 100 mL of water and 100 mL of methanol, followed by vacuum drying to synthesize a wholly aromatic polyimide.

In the infrared absorption spectrum (Fig. 1) of the synthesized polymers 1778cm ^{- 1} and 1716cm ^- is already in the C = O absorption band deugi in 1, already CN absorption band of deugi at 1376cm ^-1 were observed. The synthesized polymer was dissolved in NMP to obtain a polyimide film having a yellow index of 5 or less and a light transmittance of 90% or more at 450 nm (FIG. 6).

Example 2: Production of film of wholly aromatic polyimide

184 mL of N -methyl-2-pyrrolidone was added to a 500-mL two-necked round bottom flask substituted with nitrogen gas, and 15.510 g (0.05 mol) of 4,4'-oxydiphthalic anhydride and 2,2- 16.713 g (0.05 mol) of bis (4-aminophenyl) hexafluoropropane was added and reacted at 0 to 25 ° C for 24 hours to synthesize polyamic acid.

Next, 25.522 g (0.25 mol) of acetic anhydride and 19.775 g (0.25 mol) of pyridine were added to the solution, and the mixture was stirred at 80 ° C. for 24 hours, Reprecipitated. After filtration, the filtrate was washed with 100 mL of water and 100 mL of methanol and vacuum-dried to synthesize a wholly aromatic polyimide.

In the infrared absorption spectrum (Fig. 1) of the synthesized polymers 1777cm ^{- 1} and 1716cm ^- is already in the C = O absorption band deugi in 1, already CN absorption band of deugi at 1375cm ^-1 were observed. The synthesized polymer was dissolved in NMP to obtain a polyimide film having a yellow index of 5 or less and a light transmittance of 450 nm at 90% or more (Fig. 6).

Example 3: Production of film of partially aliphatic polyimide

190 mL of N -methyl-2-pyrrolidone was added to a 500-mL two-neck round bottom flask substituted with nitrogen gas, and 11208 g (0.05 mol) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride, And 9.913 g (0.05 mol) of 4,4'-diaminodiphenylmethane were placed and reacted at 0 to 25 ° C for 24 hours to synthesize polyamic acid.

Next, 102.09 g (1.0 mol) of acetic anhydride and 79.1 g (1.0 mol) of pyridine were added to the solution in an amount corresponding to 20 times the number of repeating units of polyamic acid, and the mixture was stirred at 40 ° C for 24 hours, Reprecipitated. After filtration, the mixture was washed with 100 mL of water and 100 mL of methanol, followed by vacuum drying to synthesize a partially aliphatic polyimide.

In the infrared absorption spectrum of the synthesized polymer (Fig. 2) 1783cm ^{- 1} and 1719cm ^- is already in the C = O absorption band deugi in 1, already CN absorption band of deugi at 1379cm ^-1 were observed. The synthesized polymer was dissolved in NMP to obtain a polyimide film having a yellow index of 5 or less and a light transmittance of 450 nm at 90% or more (Fig. 7).

Example 4: Production of film of partially aliphatic polyimide

190 mL of N -methyl-2-pyrrolidone was added to a 500-mL two-neck round bottom flask substituted with nitrogen gas, and 11208 g (0.05 mol) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride, And 9.913 g (0.05 mol) of 4,4'-diaminodiphenylmethane were placed and reacted at 0 to 25 ° C for 24 hours to synthesize polyamic acid.

Next, 204.18 g (2.0 mol) of acetic anhydride corresponding to 40 times the number of moles of the repeating unit of the polyamic acid was added to the solution, and 158.2 g (2.0 mol) of pyridine was added to the solution. The solution was stirred at 40 ° C for 24 hours, Reprecipitated. After filtration, the mixture was washed with 100 mL of water and 100 mL of methanol, followed by vacuum drying to synthesize a partially aliphatic polyimide.

In the infrared absorption spectrum (Fig. 2) of the synthesized polymers 1781cm ^{- 1} and 1720cm ^-1 in the already C = O absorption band of in deugi, 1378cm ^-1 The absorption band of CN already deugi was observed. The synthesized polymer was dissolved in NMP to obtain a polyimide film having a yellow index of 5 or less and a light transmittance of 450 nm at 90% or more (Fig. 7).

Example 5: Production of film of partially aliphatic polyimide

192 mL of N -methyl-2-pyrrolidone was added to a 500-mL 2-necked round bottom flask substituted with nitrogen gas, and 10.910 g (0.05 mol) of pyromellitic dianhydride and 4,4'-methylenebis Hexylamine) was added thereto, followed by reaction at 0 to 25 ° C for 24 hours to synthesize polyamic acid.

Next, 56.558 g (0.25 mol) of anhydrous benzoic acid and 24.032 g (0.25 mol) of 1,2-dimethylimidazole corresponding to 5 times the number of repeating units of the polyamic acid were added to the solution, After stirring for a time, re-precipitation was performed using water. After filtration, the mixture was washed with 100 mL of water and 100 mL of methanol, followed by vacuum drying to synthesize a partially aliphatic polyimide.

In the infrared absorption spectrum of the synthesized polymer (Fig. 3) 1772cm ^{- 1} and 1716cm ^- is already in the C = O absorption band deugi in 1, already CN absorption band of deugi at 1381cm ^-1 were observed. The synthesized polymer was dissolved in NMP to obtain a polyimide film having a yellow index of 5 or less and a light transmittance of 450 nm at 90% or more (Fig. 8).

Example 6: Film Production of Partial Aliphatic Polyimide

192 mL of N -methyl-2-pyrrolidone was added to a 500-mL 2-necked round bottom flask substituted with nitrogen gas, and 10.910 g (0.05 mol) of pyromellitic dianhydride and 4,4'-methylenebis Hexylamine) was added thereto, followed by reaction at 0 to 25 ° C for 24 hours to synthesize polyamic acid.

Next, 32.535 g (0.25 mol) of anhydrous propionic acid and 14.778 g (0.25 mol) of trimethylamine corresponding to 5 times the number of repeating units of the polyamic acid were added to the solution, stirred at 40 ° C for 24 hours, Lt; / RTI > After filtration, the mixture was washed with 100 mL of water and 100 mL of methanol, followed by vacuum drying to synthesize a partially aliphatic polyimide.

In the infrared absorption spectrum of the synthesized polymer (Fig. 3) 1772cm ^{- 1} and 1716cm ^- is already in the C = O absorption band deugi in 1, already CN absorption band of deugi at 1381cm ^-1 were observed. The synthesized polymer was dissolved in NMP to obtain a polyimide film having a yellow index of 5 or less and a light transmittance of 450 nm at 90% or more (Fig. 8).

Example 7: Film production of battery cyclic polyimide

Into a 500-mL 2-necked round bottom flask substituted with nitrogen gas, 146 mL of N -methyl-2-pyrrolidone was added, and 10.507 g (0.05 mol) of 1,2,3,4-cyclopentanetetracarboxylic dianhydride was added thereto. And 5.709 g (0.05 mol) of 1,4-diaminocyclohexane were added thereto, and reacted at 0 to 25 ° C for 24 hours to synthesize polyamic acid.

Next, 25.522 g (0.25 mol) of acetic anhydride and 19.775 g (0.25 mol) of pyridine were added to the solution, and the mixture was stirred at 40 ° C for 1 hour, Reprecipitated. After filtration, the filtrate was washed with 100 mL of water and 100 mL of methanol, followed by vacuum drying to synthesize all aliphatic polyimide.

In the infrared absorption spectrum (Fig. 4) of the synthesized polymers 1775cm ^{- 1} and 1719cm ^-1 in the already C = O absorption band of in deugi, 1387cm ^-1 The absorption band of CN already deugi was observed. The synthesized polymer was dissolved in NMP to obtain a polyimide film having a yellow index of 5 or less and a light transmittance of 450 nm at 90% or more (FIG. 9).

Example 8: Film production of battery cyclic polyimide

Into a 500-mL 2-necked round bottom flask substituted with nitrogen gas, 146 mL of N -methyl-2-pyrrolidone was added, and 10.507 g (0.05 mol) of 1,2,3,4-cyclopentanetetracarboxylic dianhydride was added thereto. And 5.709 g (0.05 mol) of 1,4-diaminocyclohexane were added thereto, and reacted at 0 to 25 ° C for 24 hours to synthesize polyamic acid.

Then 25.522 g (0.25 mol) of acetic anhydride and 19.775 g (0.25 mol) of pyridine were added to the solution, and the mixture was stirred at 40 ° C for 48 hours, Reprecipitated. After filtration, the filtrate was washed with 100 mL of water and 100 mL of methanol, followed by vacuum drying to synthesize all aliphatic polyimide.

In the infrared absorption spectrum of the synthesized polymer (Fig. 4) 1774cm ^{- 1} and 1718cm ^- is already in the C = O absorption band deugi in 1, already CN absorption band of deugi at 1387cm ^-1 were observed. The synthesized polymer was dissolved in NMP to obtain a polyimide film having a yellow index of 5 or less and a light transmittance of 450 nm at 90% or more (Fig. 9).

Comparative Example 1: Film Production of Copolymer Polyimide

To a 500-mL 2-neck round bottom flask substituted with nitrogen gas was added 267 mL of N -methyl-2-pyrrolidone, and 4.903 g (0.025 mol) of 1,2,3,4-cyclobutane tetracarboxylic dianhydride and 3,3 (0.025 mol) of 4,4'-benzophenone tetracarboxylic dianhydride and 16.713 g (0.05 mol) of 2,2-bis (4-aminophenyl) hexafluoropropane. C for 24 hours to synthesize polyamic acid.

Next, 10.209 g (0.1 mol) of acetic anhydride and 7.91 g (0.1 mol) of pyridine were added to the solution in an amount corresponding to twice the repeating unit of the polyamic acid, and the mixture was refluxed at 160 ° C. for 12 hours, And then reprecipitated using an excessive amount of ice water. Filtered, washed with 100 mL of water and 100 mL of methanol, and vacuum-dried to synthesize a copolymer polyimide.

In the infrared absorption spectrum of the synthesized polymer (Fig. 5) 1778cm ^{- 1} and 1719cm ^- is already in the C = O absorption band deugi in 1, already CN absorption band of deugi at 1380cm ^-1 were observed. The synthesized polymer was dissolved in NMP to obtain a polyimide film having a yellow index of 56 and a light transmittance of 450 nm at 90% or less (Fig. 10).

Comparative Example 2: Film production of copolymer polyimide

N -methyl-2-pyrrolidone (277 mL) was added to a 500-mL two-neck round bottom flask substituted with nitrogen gas, and 4.903 g (0.025 mol) of 1.2.3.4-cyclobutane tetracarboxylic dianhydride and 3,3 (0.025 mol) of 4,4'-benzophenone tetracarboxylic dianhydride and 16.713 g (0.05 mol) of 2,2-bis (4-aminophenyl) hexafluoropropane. C for 24 hours to synthesize polyamic acid.

Next, the synthesized polyamic acid solution was heated at 250 to 300 ° C in an oven or hot plate stepwise and heated for 12 hours to obtain polyimide.

In the infrared absorption spectrum of the synthesized polymer (Fig. 5) 1777cm ^{- 1} and 1718cm ^- is already in the C = O absorption band deugi in 1, already CN absorption band of deugi at 1381cm ^-1 were observed. The synthesized polymer was dissolved in NMP to obtain a polyimide film having a yellow index of 67 and a light transmittance of 450 nm at 90% or less (FIG. 10).

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative Example 1 Comparative Example 2 Imidated
Reaction temperature 20 ℃ 80 ℃ 40 ℃ 40 ℃ 40 ℃ 40 ℃ 40 ℃ 40 ℃ 160 ° C 300 ° C Polyamic acid
The molar ratio of the catalyst and the dehydrating agent to the repeating unit 1: 5 1: 5 1: 20 1: 40 1: 5 1: 5 1: 5 1: 5 1: 2 use
Do not catalyst Pyridine Pyridine Pyridine Pyridine 1,2-dimethyl
Imidazole try
Methylamine Pyridine Pyridine Pyridine not used Dehydrating agent myriad
Acetic acid myriad
Acetic acid myriad
Acetic acid myriad
Acetic acid myriad
Benzoic acid myriad
Propionic acid myriad
Acetic acid myriad
Acetic acid myriad
Acetic acid not used Imidated
time 24 hours 24 hours 24 hours 24 hours 24 hours 24 hours 1 hours 48 hours 12 hours 24 hours Yellow index 5 or less 5 or less 5 or less 5 or less 5 or less 5 or less 5 or less 5 or less 56 67 Permeability
(450 nm) 97 94 99 96 96 96 98 99 71 75 To an organic solvent of polyimide
Solubility in water Record well Record well Record well Record well Record well Record well Record well Record well Partial dissolution Does not melt Flexibility of polyimide film tenderness tenderness tenderness tenderness tenderness tenderness tenderness tenderness Film breakage film
fracture Synthesized
Polyimide
Heat
Sun temperature > 500 ° C > 500 ° C 470 ℃ 470 ℃ 480 ° C 480 ° C 413 DEG C 413 DEG C 428 ° C 451 DEG C Synthesized
Polyimide
De molecular weight 46816 45128 33527 32419 35201 35958 13521 10520 48219 64691

As shown in Table 1, in Examples 1 to 8, the imidization reaction was carried out within a temperature range of 20 to 80 ° C, and the polyimide obtained by the above method had good solubility in an organic solvent. A polyimide film having a thickness in the range of 20 to 30 mu m was produced using the polyimide to evaluate the characteristics thereof. As a result, a colorless, transparent and flexible film having a transmittance of 90% or more at a wavelength of 450 nm and a yellow index of 5 or less was obtained I could confirm.

On the other hand, in Comparative Examples 1 and 2, the imidization reaction was carried out at 160 ° C. or higher. A polyimide film having a thickness in the range of 20 to 30 μm was produced using the polyimide obtained by the above- It was confirmed that a film having a transmittance at 450 nm of 80% or less and a yellow index of 50 or more was obtained.

Claims (14)

(a) preparing a polyamic acid solution by mixing dianhydride and diamine in a solvent;
(b) adding a chemical dehydrating agent and a catalyst to the prepared polyamic acid solution, wherein the chemical dehydrating agent and the catalyst are added at the same to 50-fold molar ratio with respect to the polyamic acid repeating unit;
(c) preparing a polyimide solution by imidizing the polyamic acid solution at 25 to 60 캜;
(d) applying the prepared polyimide solution to a substrate; And
(e) drying the applied polyimide solution at a temperature in the range of 20 to 100 캜 and at a pressure of 1 atm or less to produce a polyimide film; Lt; / RTI >
Wherein said dianhydride is at least one substituted or unsubstituted dianhydride, said diamine being at least one substituted or unsubstituted diamine,
A method for producing a polyimide film.
The method according to claim 1,
The polyamic acid solution is prepared by sequentially preparing the polyamic acid solution prepared in step (a) by re-precipitation, filtration and drying, and dissolving the polyamic acid powder in a solvent to prepare a polyamic acid solution. Wherein the polyimide film is a polyimide film.
The method according to claim 1,
The polyimide solution prepared in step (c) is re-precipitated, filtered and dried to prepare a polyimide powder. The polyimide powder is dissolved in a solvent to prepare a polyimide solution. Wherein the polyimide film is a polyimide film.
The method according to claim 1,
Wherein the dianhydride is an aromatic or aliphatic dianhydride.
5. The method of claim 4,
Wherein the dianhydride is a dianhydride of the following formula (1).

≪ Formula 1 >
(R ₁ in the formula 1 is a compound of the following

. ≪ / RTI >
The method according to claim 1,
Wherein the diamine is an aromatic or aliphatic diamine.
The method according to claim 6,
Wherein the diamine is a diamine of the following formula (2).

(2)
(Wherein R < 2 _> represents the following compound

. &Lt; / RTI &gt;
4. The method according to any one of claims 1 to 3,
The solvent may be N -methyl-2-pyrrolidone, N, N -dimethylacetamide, N, N -dimethylformamide, N -vinylpyrrolidone, N -methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide, meta-cresol, gamma-butyrolactone, Butyl cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, butyl carbitol acetate, ethylene glycol, ethyl lactate, butyl lactate, cyclohexanone, cyclopentanone, hexane (normal hexane, (Isopropanol, isopropanol), butanol (normal-, iso-, tertiary-), cyclohexanol, octanol, cyclohexane, cyclohexane, cyclohexane, cyclohexane, pentane, heptane, benzene, toluene, xylene, methanol, ethanol, Benzyl alcohol, acetone, methyl ethyl ketone, methyl butyl ketone, methyl acetate, ethyl acetate, diethyl ether, isopropyl ether, tetrahydrofuran, chloroform, dioxane, diethylformamide, sulfolane, formic acid, , Acetone The Tra days and a method of producing a polyimide film tetralin in one single solvent or a mixed solvent of two or more of the species selected from the group consisting of.
The method according to claim 1,
Wherein the step (a) is performed at a temperature of 0 to 30 캜.
The method according to claim 1,
Wherein the step (a) is performed for 1 to 48 hours.
The method according to claim 1,
Wherein the chemical dehydrating agent is at least one dehydrating agent selected from the group consisting of acetic anhydride, anhydrous propionic acid, anhydrous butyric acid, anhydrous benzoic acid, anhydrous adipic acid, anhydrous isophthalic acid, phthalic anhydride and trimellitic anhydride. Gt;
The method according to claim 1,
The catalyst may be selected from the group consisting of trimethylamine, triethylamine, methylpyrrolidine, N, N -dimethylhexylamine, imidazole, 1,2-dimethylimidazole, N -methylimidazole, N- Methylimidazole, N -benzyl-2-methylimidazole, isoquinoline, 3,5-di-methylimidazole, A polyimide film which is at least one catalyst selected from the group consisting of methyl pyridine, 3,4-dimethylpyridine, 2,5-dimethylpyridine, 2,4-dimethylpyridine and 4-n- Gt;
The method according to claim 1,
Wherein the step (c) is performed for 10 minutes to 72 hours.
The method according to claim 1,
Wherein the polyimide in the polyimide solution in step (d) is 1 to 90 wt% based on the total weight of the solution.

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