WO2018038309A1 - Polyimide precursor resin composition with improved resin stability and heat resistance and having transparency, method for producing polyimide film using same, and polyimide film produced thereby - Google Patents

Abstract

The present invention relates to a transparent polyamic acid precursor resin composition which does not cause a white cloudy phenomenon during solution casting while having excellent mechanical properties, high heat resistance and low thermal expansion coefficient by optimizing aromatic diamine and acid dianhydride for improving heat resistance and mechanical properties, and an organic solvent in which a white turbidity phenomenon does not occur; a method for producing a polyimide film using the same; and a polyimide film produced thereby.

Description

Polyimide precursor resin composition having improved resin stability, heat resistance and transparency, a polyimide film production method using the same, and a polyimide film produced thereby

The present invention provides a polyimide precursor resin composition having excellent mechanical properties, high heat resistance, low coefficient of thermal expansion, but having no transparency in solution casting, and a polyimide film manufacturing method using the same, and a polyimide film prepared thereby The present invention relates to a flexible display substrate material and a semiconductor material.

Flexible polymer materials are attracting attention as substrate materials of flexible displays, which are being spotlighted as next generation display devices.

The flexible device generally uses an organic light emitting diode (OLED) display, and a TFT process with a high process temperature (300 to 500 ° C) is used. Polymer materials that withstand such high process temperatures are extremely limited, and polyimide (PI) resin, which is a polymer having excellent heat resistance, is mainly used.

An organic light emitting diode (OLED) display manufactures a display by coating a resin on a glass substrate, thermosetting and filming the film, and removing the glass substrate from the glass substrate after several steps. When the resin is applied to the glass substrate during the manufacturing process, the stability of the resin at room temperature is important. If the stability of the resin is not secured, a uniform film may not be formed after curing due to agglomeration of the resin, cloudiness, etc., and eventually, product defects may occur. In addition, product defects may occur due to thermal shock due to the high temperature of the TFT deposition process during the post process. Therefore, a polyimide resin (PI) having resin stability at room temperature, high heat resistance and low coefficient of thermal expansion (CTE) is required.

Korean Patent Laid-Open Publication No. 2015-108812 discloses a polyamic acid solution and a film using the same, which can be applied as a base layer or a protective layer of a display device because of its excellent thermal properties with low thermal expansion rate and high thermal decomposition temperature. This may not be secured, and the uniform film may not be formed after curing due to agglomeration of the resin, cloudiness, and the like, and eventually, product defects may occur.

In addition, Korean Patent Laid-Open Publication No. 2013-35691 discloses a composition and a manufacturing method for preparing a copolymerized polyamide-imide film, but this has a limitation in the economic part of the process because it must go through a process of generating and removing by-products. .

Therefore, the polyimide composition having high heat resistance, low coefficient of thermal expansion, and excellent mechanical strength, as well as the stability of the resin, and the manufacturing process require a relatively simple method of raising a manufacturing method.

(Prior art document)

(Patent literature)

       (Patent Document 1) 1: Korean Patent Application Publication No. 2015-108812

(Patent Document 2) 2: Korean Laid-Open Patent No. 2013-35691

In order to solve the above problems, the present inventors have improved the composition of aromatic diamine and acid dianhydride compounds, and the composition of organic solvents that do not cause turbidity, in the production of polyimide films having improved heat resistance and optimum mechanical properties. This invention was completed by discovering the polyimide precursor resin composition which has transparency, resin stability, high heat resistance, and a low coefficient of thermal expansion than the conventional polyimide film.

Accordingly, an object of the present invention is to provide a polyimide precursor resin composition that can be used as a flexible display substrate material having transparency, resin stability, high heat resistance, and low coefficient of thermal expansion.

It is another object of the present invention to provide a method for producing a polyimide resin film using the composition.

In addition, the present invention has a glass transition temperature of 300 ℃ or more, the thermal expansion coefficient in the range of 100 to 300 ℃ 25 ppm / ℃ or less, wavelength of 550 nm based on the thickness of the film prepared by the above method 10 ~ 15 ㎛ An object thereof is to provide a polyimide resin film having a transmittance of 85% or more and a yellow index (YI) of 7 or less at a wavelength of 550 nm.

The present invention provides a polyimide precursor resin composition comprising an aromatic diamine component, an acid dianhydride compound, and an organic solvent, wherein the aromatic diamine component (A) is 2,2'-bis (trifluoromethyl) which is a fluorinated aromatic diamine monomer. -4,4'-diaminobiphenyl (TFMB), or N- (4-amino phenyl) -4-aminobenzamide (DBA), which is a polyamine monomer having an amide group, or a mixture thereof; The dianhydride compound (B) is 4,4- (hexafluoroisopropylidene) diphthalic anhydride (6FDA) which is a fluorinated aromatic acid dianhydride and pyromellitic dianhydride (PMDA) which is a non-fluorinated aromatic acid dianhydride, or 3 ', A mixture comprising 4,4'-biphenyltetracarboxylic dianhydride (BPDA), wherein the organic solvent (C) is gamma-butyrolactone (GBL) and N-methyl-2-pyrrolidone (NMP) Mixtures of, or gamma-butyrolactone (GBL) and 3-methoxy-N, N-dimethyl propaneami Provides (DMPA) or a mixture 3-methoxy -N, N- dimethylpropanamide (DMPA) resin stability, high heat resistance is improved transparent polyimide precursor composition, characterized in that is water alone a.

In another aspect, the present invention provides a method for producing a transparent polyimide resin film, characterized in that the polyamic acid solution prepared by using the composition is heat-treated.

In addition, the present invention has a glass transition temperature of 300 ℃ or more, the thermal expansion coefficient in the range of 100 to 300 ℃ 25 ppm / ℃ or less, wavelength of 550 nm based on the thickness of the film prepared by the above method 10 ~ 15 ㎛ A transparent polyimide resin film having a transmittance of 85% or more and a yellow index (YI) of 550 nm at a wavelength of 7 or less is provided.

According to the present invention, the resin stability is excellent at room temperature, which does not cause cloudiness during solution casting, compared to the conventional polyamic acid solution, and provides excellent mechanical properties, optical properties, and heat resistance properties during film production through thermal curing. By doing so, it can be usefully used for a flexible display substrate material, a semiconductor material and the like.

In addition, the present invention can secure process competitiveness because it does not go through the process of generating and removing by-products compared to the prior art when preparing a polyamic acid solution.

Figure 1 shows the clouding phenomenon (room stability) according to the organic solvent (GBL: NMP = 70 mol%: 30 mol%) of Example 1 when casting a polyamic acid solution on a glass substrate at room temperature.

Figure 2 shows the clouding phenomenon (room stability) according to the organic solvent (GBL: DMPA = 70 mol%: 30 mol%) of Example 2 when casting a polyamic acid solution on a glass substrate at room temperature.

Figure 3 shows the clouding phenomenon (at room temperature stability) according to the organic solvent (100 mol% of NMP alone) of Comparative Example 3, when casting a polyamic acid solution on a glass substrate at room temperature.

The polyimide precursor resin composition (hereinafter referred to as the 'polyamic acid composition') of the present invention has a composition of an aromatic diamine and an acid dianhydride compound having improved heat resistance and optimum mechanical properties, and a composition of an organic solvent in which no turbidity occurs. And its usage is optimized to provide a transparent polyimide film having high heat resistance, low coefficient of thermal expansion and excellent mechanical strength. The polyimide precursor composition, in other words the 'polyamic acid composition' according to the present invention, means a composition used to prepare a polyamic acid solution used for preparing a polyimide film.

Specifically, the polyamic acid composition according to the present invention comprises an aromatic diamine component (A) comprising a fluorinated aromatic diamine or an amide group or a mixture thereof, an acid containing a fluorinated aromatic acid dianhydride and a non-fluorinated aromatic acid dianhydride compound. An organic solvent comprising N-methyl-2-pyrrolidone (NMP) or 3-methoxy-N, N-dimethyl propanamide (DMPA) in dianhydride compound (B), gamma-butyrolactone (GBL) C), and a polyamic acid composition comprising the reaction catalyst (D). The specific description of each component is as follows.

(A) aromatic diamine component

The aromatic diamine component in the present invention is 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (TFMB) which is a fluorinated aromatic diamine monomer, or N- (which is a polyamine monomer having an amide group. 4-amino phenyl) -4-aminobenzamide (DBA), or mixtures thereof.

Specifically, the fluorinated aromatic diamine monomer 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (TFMB) is 30 to 100 mol% based on the total diamine compound, N- (4-amino phenyl) -4-aminobenzamide (DBA) is 5 to 50 mol% relative to the total diamine compound, and may further comprise a balance of non-fluorinated aromatic diamine.

When the aromatic diamine component (A) contains a fluorinated aromatic diamine having a fluorine substituent introduced therein, it is possible to provide a polyimide film having excellent optical properties due to the charge transfer effect between the fluorine substituents in the molecular chain. have.

In addition, when used in combination with such fluorinated aromatic diamine N- (4-amino phenyl) -4-aminobenzamide (DBA), polyimide film having excellent heat resistance and low coefficient of thermal expansion due to the rigidity of the aromatic structure and the amide structure Can be provided.

When the fluorinated aromatic diamine and N- (4-amino phenyl) -4-aminobenzamide are mixed as the aromatic diamine component, the polyimide film has improved optical properties and thermal properties while maintaining optical properties as compared with using only fluorinated aromatic diamine. Can be prepared.

The fluorinated aromatic diamine is not particularly limited as long as it is an aromatic diamine containing fluorine. For example, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-Bis (trifluoromethyl) -4,4'-Diaminobiphenyl, TFMB), bis aminohydride Bisaminohydroxyphebyl hexafluoropropane (DBOH), bis aminophenoxy phenyl hexafluoropropane (4BDAF), 2,2'-bis (trifluoromethyl) -4,3'-dia Minobiphenyl (2,2'-Bis (trifluoromethyl) -4,3'-Diaminobiphenyl), and 2,2'-bis (trifluoromethyl) -5,5'-diaminobiphenyl (2,2 ' At least one selected from the group consisting of -Bis (trifluoromethyl) -5,5'-Diaminobiphenyl) may be used.

However, in the present invention, it is preferable to use 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (TFMB), which can simultaneously improve the permeability and heat resistance characteristics.

In this case, the TFMB is 30 to 100 mol%, preferably 50 to 90 mol% based on 100 mol% of the total diamine compound, and the charge transfer effect between intermolecular fluorine substituents when used within the above range. ) May further improve the optical properties of the polyimide film.

In addition, the present invention may include not only fluorinated aromatic diamine monomers such as TFMB, but also non-fluorinated aromatic diamine monomers. At this time, the fluorinated aromatic diamine and non-fluorinated aromatic are used so that the total is 100 mol%.

On the other hand, the polyimide resin may include a compound having or forming an amide structure for excellent heat resistance and low coefficient of thermal expansion. Compounds capable of forming such an amide structure include an acid halide and a dicarboxylic acid. Examples include p-terephthaloyl chloride (TPC), isophthaloyl dichloride (IPC), 1,3-adamantanedicarbonyl dichloride (ADC) , 5-norbornene-2,3-dicarbonyl chloride (NDC), 4,4'-benzoyl dichloride (4,4'-benzoyl dichloride, BDC), 1 1,4-naphthalene dicarboxylic acid dichloride (1,4-NaDC), 2,6-naphthalene dicarboxylic acid dichloride (2,6-naphthalene dicarboxylic acid dichloride) 6-NaDC), 1,5-naphthalene dicarboxylic acid dichloride (1,5-NaDC), terephthalic acid (TPA), isophthalic acid (IPA) phthalic acid (Phthalic acid, PA), 4,4'-biphenyl dicarboxylic acid (BDA), and naphthalene dicarboxylic acid (NaDA) It is at least one selected from the group consisting of.

However, these compounds form an amide structure, and by-products such as HCl and H ₂ O may be generated, and may lower the film properties when producing an imide film.

Therefore, in the present invention, by using N- (4-aminophenyl) -4-aminobenzamide (N- (4-aminophenyl) -4-aminobenzamide, DBA), which is a diamine compound having an amide, By introducing an amide group into the chain, heat resistance and low coefficient of thermal expansion can be realized. The content of N- (4-amino phenyl) -4-aminobenzamide (DBA) is not particularly limited, but may be 5 to 50 mol%, preferably 5 to 20 mol% based on 100 mol% of the diamine compound. Can be.

(B) acid dianhydride compounds

The aromatic acid dianhydride compounds of the present invention comprise 20 to 80 mol% of fluorinated aromatic acid dianhydrides and 80 to 20 mol% of non-fluorinated aromatic acid dianhydride compounds.

When the fluorinated aromatic acid dianhydride and the non-fluorinated aromatic acid dianhydride compound are mixed and used as in the present invention, the optical and heat resistance properties of the polyimide film may be simultaneously improved. Due to the fluorine substituent of the fluorinated aromatic dianhydride, a polyimide film having excellent optical properties can be produced, and a polyimide film having excellent heat resistance can be prepared due to the rigid molecular structure of the aromatic dianhydride.

Fluorinated aromatic acid dianhydrides are aromatic acid dianhydrides having fluorine substituents introduced therein, for example, 4,4- (hexafluoroisopropylidene) diphthalic anhydride (4,4 '-(Hexafluoroisopropylidene) diphthalic anhydride (6FDA) ), And 4,4- (4,4-hexafluoroisopropylidenediphenoxy) bis- (phthalic anhydride) (4,4 '-(4,4'-Hexafluoroisopropylidenediphenoxy) bis- (phthalic anhydride, 6- One or more selected from the group consisting of FDPDA) can be used, but in the present invention, 6FDA is preferably used as the fluorinated aromatic acid dianhydride.

The fluorinated aromatic acid dianhydride is 20 to 80 mol%, preferably 40 to 70 mol%, based on 100 mol% of the total acid dianhydride, and can realize high permeability and low yellowness of the polyimide film within the above range. have.

Next, the non-fluorinated aromatic acid dianhydride is an aromatic acid dianhydride to which no fluorine substituent is introduced, and pyromellitic dianhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic acid Dianhydrides (3,3'4,4'-biphenyltetracarboxylic acid dianhydride, BPDA), 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride (3,3', 4,4'-benzophenonetetracarboxylic dianhydride , BTDA), 4,4'-oxydiphthalic anhydride (ODPA), 2,2-bis [4-3,4-dicarboxyphenoxy] phenyl] propane anhydride (2,2- Bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride (BPADA), 3, 3 ', 4, 4'-diphenyl sulfone tetracarboxylic anhydride (3,3,4,4-Diphenyl sufone tetracarboxylic dianhydride , DSDA), and ethylene glycol bis (4-trimellitate anhydride) (ethylene glycol bis (4-trimellitate anhydride), TMEG) may be used at least one selected from the group consisting of, but in the present invention Directly, PMDA or BPDA or mixtures thereof are used as the non-fluorinated aromatic acid dianhydride.

In this case, the non-fluorinated aromatic acid dianhydride is 80 to 20 mol%, preferably 30 to 50 mol%, based on 100 mol% of the total acid dianhydride, further improving heat resistance while maintaining the high permeability and low yellowness of the polyimide film. Can be lowered.

(C) organic solvent

The organic solvent in the present invention is m-cresol, N-methyl-2-pyrrolidone (NMP), N, N- dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), di Polar solvents such as ethyl acetate (DEA), 3-methoxy-N, N-dimethyl propanamide (DMPA), low-boiling solvents such as tetrahydrofuran (THF), chloroform, or gamma-butyrolactone and GBL Low absorption solvents.

The organic solvent used in the present invention plays an important role in improving the clouding phenomenon, where the clouding phenomenon can be confirmed through FIGS. 1 to 3. 1 shows room temperature stability (without turbidity) for 70 mol% GBL and 30 mol% NMP organic solvent when casting a polyamic acid solution on a glass substrate at room temperature, and FIG. 2 shows 70 mol% GBL and 30 mol DMPA. It shows the room temperature stability (without cloudy phenomenon) with respect to the organic solvent of%. On the other hand, Figure 3 shows the turbidity phenomenon for the organic solvent of 100 mol% NMP alone.

Therefore, in the present invention, in order to improve the clouding phenomenon in solution casting at room temperature, a mixture of gamma-butyrolactone (GBL) and N-methyl-2-pyrrolidone (NMP), or gamma-butyrolactone (GBL) And mixtures of 3-methoxy-N, N-dimethyl propanamide (DMPA) or 3-methoxy-N, N-dimethyl propanamide (DMPA) alone.

At this time, the amount of the organic solvent used is 30 to 70 mol% of gamma-butyrolactone (GBL) and N-methyl-2-pyrrolidone (NMP) or 3-methoxy-N, N-dimethyl propanamide (DMPA) 70 to Preference is given to using 30 mol%. More preferably, 30-50 mol of N-methyl-2-pyrrolidone (NMP) or 3-methoxy-N, N-dimethyl propanamide (DMPA) in 50-70 mol% of gamma-butyrolactone (GBL) %to be. Or 100 mol% of gamma-butyrolactone (GBL) alone.

(D) reaction catalyst

The reaction catalyst of the present invention may further include at least one selected from the group consisting of trimethylamine, xylene, pyridine, and quinoline, depending on the reactivity, but is not necessarily limited thereto. Does not. In addition, the polyamic acid composition may contain a small amount of additives such as a plasticizer, an antioxidant, a flame retardant, a dispersant, a viscosity modifier, and a leveling agent, as necessary, within a range that does not significantly impair the object and effect of the present invention.

In addition, the polyamic acid solution obtained by polymerization using an aromatic diamine component, an acid dianhydride compound, an organic solvent, and a reaction catalyst, which is a polyamic acid composition according to the present invention, has a solid content of 10 to 40 wt%, based on the total weight of the polyamic acid solution, Preferably it contains 10 to 25% by weight. If the solid content is less than 10% by weight there is a limit to increase the thickness of the film during film production, if the solid content is more than 40% by weight there is a limit in controlling the viscosity of the polyamic acid is formed within the above range.

Specifically, the polyamic acid solution is an organic solvent content based on a solid content of 10 to 40wt% condition, and mixed with 95 to 100 mol% of aromatic diamine components and 100 to 105 mol% of acid dianhydride compounds 10 to 70 ℃ temperature conditions It is preferable to carry out for 24 to 48 hours. At this time, the reaction temperature may be fluid depending on the monomer used.

Here, the acid dianhydride compound is preferably added in an excess of -5 to 5 mol% relative to the aromatic diamine component to reach the target viscosity, for reasons of proper viscosity control and storage stability.

The polyamic acid solution produced through this reaction preferably has a viscosity in the range of 1,000 to 7,000 cP. If the viscosity is less than 1,000 cP, there is a problem in obtaining an appropriate level of film thickness, and if it is more than 7,000 cP, there is a problem in uniform coating and effective solvent removal, so it is preferable to be within the above range.

In addition, in the present invention, the transparent polyimide film and a method of manufacturing the same are as follows. The present invention provides a transparent polyimide film prepared by thermal imidating a polyamic acid solution prepared from the polyamic acid composition described above. The polyamic acid solution according to the present invention is viscous, and is prepared by coating and heat-treating the glass substrate in a suitable manner during film production. The coating method may be used without limitation to known conventional methods, for example, spin coating (dip coating), dip coating (Dip coating), solvent casting (Solvent casting), slot die coating, spray coating (Spray coating) ), But is not limited thereto.

The polyamic acid composition of the present invention may be prepared into a polyimide film by heat treatment in a high temperature convection oven. At this time, the heat treatment condition is carried out under a nitrogen atmosphere, it is carried out for 30 to 120 minutes at 100 ~ 450 ℃ conditions. More preferably, the film is obtained under temperature and time conditions of 100 ° C / 30min, 220 ° C / 30min, 350 ° C / 30mim. This is because of the imidization which can maximize the removal of the proper solvent and properties.

Since the transparent polyimide film of the present invention is produced using the polyamic acid composition, it exhibits high transparency and has a low coefficient of thermal expansion.

In the polyimide film of the present invention, the film has a thickness of 10 to 15 µm, a glass transition temperature of 300 ° C. or higher and a thermal expansion coefficient of 25 ppm / ° C. or lower, preferably 15 ppm / ° C. or lower in the range of 100 to 300 ° C. It is low, the transmittance at a wavelength of 550 nm is high, at least 85%, and the yellowness index (YI) at a wavelength of 550 nm is 7 or less, preferably 5 or less. The polyimide film of this invention can suppress the defect of the element on a board | substrate by expansion and contraction. In addition, the polyimide film of the present invention has high light transmittance and low yellowness and can be applied to a flexible display.

The polyimide film of the present invention can be used in various fields, and particularly displays for OLEDs, displays for liquid crystal devices, TFT substrates, flexible printed circuit boards, flexible OLED surface-illuminated substrates, electronic species that require high transparency and heat resistance It may be provided as a substrate for a flexible display and a protective film such as a substrate material used.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, these examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

Comparative Example 1

As a composition shown in Table 1, 2.547 g (0.024 mole) of a diamine monomer and 17.606 g (0.055 mole) of TFMB were dissolved in an organic solvent of NMP 142.1 g and 58.5 g of a GBL, followed by nitrogen atmosphere at room temperature for 30 minutes to 1 hour. Dissolved. After the polymerization of the dianhydride-based monomers 6FDA 24.798g (0.056mole) and PMDA 5.212g (0.024mol) for 24 hours, and further added GBL 83.6g and stirred for 24 hours to prepare a polyamic acid solution (reaction temperature: 30 ° C., wherein the solids are maintained at 15% by weight relative to the total weight of the reaction solvent). The viscosity was 5,700 cP as measured by the viscosity measuring instrument (Brookfield DV2T, SC4-27).

Comparative Examples 2 to 3

A polyamic acid solution was prepared in the same manner as in Comparative Example 1, except that the content ratio of the organic solvent of Table 1 was used.

Examples 1-5

A polyamic acid solution was prepared in the same manner as in Comparative Example 1, except that the content ratio of the organic solvent of Table 1 was used.

Experimental Example 1: Measurement of Physical Properties

(1) room temperature clouding phenomenon evaluation

Drop a polyamic acid solution prepared in Examples 1 to 5 and Comparative Examples 1 to 3 onto a glass plate and raise a predetermined thickness (15 μm after heat treatment when the thickness of the solution is 100 μm based on a solid content of 15%) using a bar coater. After leaving for 30 minutes in a temperature of 25 ℃, humidity> 90% atmosphere was observed cloudy. The level of cloudiness was evaluated by quantifying the level from 0 to 5 (0: no occurrence, 5: severe occurrence).

(2) Film Preparation and Property Evaluation

The polyamic acid solution was coated on a glass plate using a bar coater and then heat treated in a high temperature convection oven. The heat treatment conditions were carried out in a nitrogen atmosphere, and the final film was obtained at the temperature and time conditions of 100 ℃ / 30 min, 220 ℃ / 30 min, 350 ℃ / 30 min. Thus obtained film was measured in the physical properties as shown in Table 2 below the results.

(a) Transmittance and Retardation

The transmittance was measured at 550 nm using a UV-Vis NIR Spectrophotometer, and the phase difference in the plane direction (R _ο ) and the phase difference in the thickness direction (R _υθ ) were measured using a birefringence measuring instrument (Retarder, Otsuka RETs-100). .

(b) Yellowness Index (YI)

It was measured using a color difference meter (LabScan XE).

(c) haze

Haze meter (TOYOSEIKI, HAZE-GARD) was measured using.

(d) thermal properties

The glass transition temperature (T _η ) and the coefficient of thermal expansion (CTE) of the film were measured using TMA 402 F3 from Netzsch. Force in the tension mode was set to 0.05 N, and the measured temperature was elevated to 350 ° C. at a rate of 5 / min at 30 ° C., and the coefficient of linear thermal expansion was measured as an average value in the range of 100 to 300 ° C. Pyrolysis temperature (T _δ , 1%) was measured using TG 209 F3 by Netzsch.

(e) mechanical properties

Instron's UTM was used to measure the mechanical properties of the film. The film specimen was measured while pulling the specimen at a speed of 50 mm / min with a width of 10 mm and a gap between the grips set to 100 mm.

division			Example 1	Example 2	Example 3	Example 4	Example 5	Comparative Example 1	Comparative Example 2	Comparative Example 3
Composition	Acid dianhydride (unit: mol%)		6FDA / PMDA = 70: 30
	Diamine (unit: mol%)		TFMB / PPD = 70: 30
	Organic Solvent Mixing Ratio (Unit: mol%)	GBL	70	70	50	30	-	50	30	-
		NMP	30	-	-		-	50	70	100
		DMPA	-	30	50	70	100	-	-	-
* 6FDA: 4,4 '-(hexafluoroisopropylidene) diphthalic anhydride (4,4'-(Hexafluoroisopropylidene) diphthalic anhydride) * PMDA: pyromellitic dianhydride * TFMB: 2,2 '-Bis (trifluoromethyl) -benzidine (2,2'-bis (trifluoromethyl) benzidine) * PPD: p-Phenylene diamine * NMP: N-methyl-2-pyrrolidone ( N-methyl-2-pyrrolidone) * GBL: gamma-Butyrolactone * DMPA: 3-methoxy-N, N-dimethyl propanamide
Property measurement	Viscosity (cP, 23 ° C)		6400	6000	5800	5600	5600	5700	5300	5000
	Turbidity occurrence level (room temperature, RH> 90%)		0	0	0	0	0	One	2	5
	Thickness (㎛)		11	12	11	13	11	10	12	11
	Transmittance (%, @ 550nm)		89	89	90	91	92	88	88	86
	Haze		0.4	0.5	0.7	0.6	0.3	0.4	0.5	0.5
	YI		5	4	4	3	3	8	10	11
	Retardation (nm)		R o	0.64	0.59	0.73	0.53	0.55	0.76	0.79	0.55
			R th	64	47	50	38	34	53	90	96
	Tg (℃)		351	348	347	351	352	355	350	355
	Td 1% (℃)		458	448	452	455	463	453	463	466
	CTE (100 ~ 300 ℃ / ppm / ℃)		14	13	13	12	14	13	13	12
	Tensile strength (MPa)		130	134	141	155	143	151	136	148
	Elongation (%)		17	15	15	13	17	18	15	19

As shown in Table 1, in the case of Example 1 using the organic solvent GBL and NMP in a predetermined ratio of 70:30 (mol%), when the solution is left at room temperature after casting the solution on the glass plate does not have a cloudy phenomenon and stability You can see that.

In addition, it can be seen that turbidity does not occur when GBL and DMPA are mixed as in Examples 2 to 4, or when DMPA is used alone as in Example 5.

This lowers the water absorption rate of GBL is effective in controlling the occurrence of turbidity as the GBL content increases. DMPA is also effective in suppressing cloudiness in the same context. In addition, it can be seen that the optical properties, thermal properties, mechanical properties of the film exhibits the same level of properties as compared to Comparative Examples 1 to 3.

Through these results, it can be confirmed that the resin stability at room temperature without deterioration of the film properties when using the GBL and NMP, GBL and DMPA in a predetermined content as the content of the organic solvent according to the present invention.

Comparative Example 4

As a composition shown in Table 2, 21.186 g (0.066 mole) of TFMB, a diamine monomer, was dissolved in 86.7 g of NMP, 117.3 g of an organic solvent, and dissolved in a nitrogen atmosphere at room temperature for 30 minutes to 1 hour. Thereafter, 29.881 g (0.067 mole) of dianhydride-based monomer was added thereto, followed by polymerization for 24 hours, and then 8 hours of GBL was added thereto, followed by stirring for 24 hours to prepare a polyamic acid solution (reaction temperature: 30 ° C. It is maintained at 15% by weight relative to the total weight.) The viscosity was 4,200 cP as measured by a viscosity measuring instrument (Brookfield DV2T, SC4-27).

Example 6

As a composition shown in Table 2 below, 2.589 g (0.024 mole) of a diamine monomer and 17.899 g (0.056 mole) of TFMB were dissolved in 86.7 g of NMP, 117.3 g of an organic solvent, and nitrogen at 30 minutes to 1 hour at ambient temperature. Dissolved. Thereafter, 25.210 g (0.057 mole) of dianhydride-based monomers and 5.299 g (0.024 mol) of PMDA were added thereto, followed by polymerization for 24 hours, followed by further addition of GBL 85.0 g to prepare a polyamic acid solution (reaction temperature: 30). The solids were then maintained to be 15% by weight relative to the total weight of the reaction solvent.) The viscosity was 6,400 cP as measured by a viscometer (Brookfield DV2T, SC4-27).

Example 7

As a composition shown in Table 2, 22.244 g (0.069 mole) of TFMB, a diamine monomer, and 0.842 g (0.004 mol) of DBA were dissolved in 86.7 g of NMP and 117.3 g of an organic solvent in a nitrogen atmosphere and at room temperature for 30 minutes to 1 hour. Dissolved. Thereafter, 6FDA 23.063g (0.052mole) and PMDA 4.848g (0.022mol), which are dianhydride monomers, were added thereto, followed by polymerization for 24 hours, followed by further addition of 85.0 g of GBL to prepare a polyamic acid solution (reaction temperature: 30 The solid content is maintained at 15% by weight relative to the total weight of the reaction solvent.) The viscosity was 4,800 cP as measured by a viscometer (Brookfield DV2T, SC4-27).

Example 8

As a composition shown in Table 2, TFMB 24.320g (0.076mole) as a diamine monomer was dissolved in 86.7g of NMP and 117.3g of GBL as an organic solvent, and dissolved in a nitrogen atmosphere at room temperature for 30 minutes to 1 hour. Thereafter, 6FDA 17.110 g (0.038 mole) and PMDA 5.035 g (0.038 mol), which were dianhydride monomers, were added thereto, followed by polymerization for 24 hours, followed by further addition of GBL 85.0 g to prepare a polyamic acid solution (reaction temperature: 30). The solids were then maintained at 15% by weight relative to the total weight of the reaction solvent.) The viscosity was 6,600 cP as measured by a viscometer (Brookfield DV2T, SC4-27).

Example 9

As a composition shown in Table 2, 2.094 g (0.019 mole) of a diamine monomer, 18.610 g (0.058 mole) of TFMB, and 0.881 g (0.004 mol) of DBA were dissolved in an organic solvent of NMP 86.7 g, GBL 117.3 g, and a nitrogen atmosphere. It was dissolved for 30 minutes to 1 hour at room temperature. Thereafter, 6FDA 24.298g (0.055mole) and PMDA 5.115g (0.023mol), which are dianhydride monomers, were added thereto, followed by polymerization for 24 hours, followed by further addition of 85.0 g of GBL to prepare a polyamic acid solution (reaction temperature: 30). The solids were then maintained at 15% by weight relative to the total weight of the reaction solvent.) Viscosity measurement equipment (Brookfield DV2T, SC4-27) showed a viscosity of 6,800 cP.

Experimental Example 2: Measurement of Physical Properties

Physical properties of the polyamic acid solution prepared in Examples 6 to 9 and Comparative Example 4 were measured in the same manner as in Experimental Example 1, and are shown in Table 2 below.

division			Example 6	Example 7	Example 8	Example 9	Comparative Example 4
Composition	Acid dianhydride	6FDA	70	70	50	70	100
		PMDA	30	30	30	30	-
		BPDA	-	-	20	-	-
	Diamine	TFMB	70	95	100	70	100
		PPD	30	-	-	25	-
		DBA	-	5	-	5	-
	Organic solvent mixing ratio (unit: mol%)	GBL: NMP = 70: 30
* 6FDA: 4,4 '-(hexafluoroisopropylidene) diphthalic anhydride (4,4'-(Hexafluoroisopropylidene) diphthalic anhydride) * PMDA: pyromellitic dianhydride * BPDA: 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (3,3', 4,4'-Biphenyltetracarboxylic dianhydride) * TFMB: 2,2'-bis (trifluoromethyl) -benzidine (2, 2'-bis (trifluoromethyl) benzidine) * PPD: p-Phenylene diamine * DBA: N- (4-amino phenyl) -4-aminobenzamide (N- (4-aminophenyl) -4 -aminobenzamide * NMP: N-methyl-2-pyrrolidone * GBL: gamma-Butyrolactone
Property measurement	Viscosity (cP, 23 ° C)		6400	4800	6600	6800	4200
	Turbidity occurrence level (room temperature, RH> 90%)		0	0	0	0	0
	Thickness (㎛)		11	11	13	10	12
	Transmittance (%, @ 550nm)		90	88	87	88	91
	Haze		0.4	0.7	0.6	0.7	0.5
	YI		5	7	7	6	5
	Retardation (nm)		R o	0.64	0.59	0.66	0.73	0.71
			R th	64	73	77	88	133
	Tg (℃)		351	360	355	349	278
	Td 1% (℃)		458	463	481	466	407
	CTE (100 ~ 300 ℃ / ppm / ℃)		14	10	11	9	34
	Tensile strength (MPa)		130	120	125	115	120
	Elongation (%)		17	15	22	15	10

As shown in Table 2, in the case of Examples 6 to 8 it can be seen that the thermal properties are improved while showing a high permeability as the content of the acid dianhydride monomer PMDA, BPDA and diamine monomer PPD, DBA increases. In addition, in the case of Example 9 using TFMB, PPD, DBA as the diamine monomer at the same time, it can be seen that the DBA can realize the heat resistance and low thermal expansion coefficient characteristics without the generation of by-products.

As a result, the polyamic acid solution prepared according to the present invention has a film thickness of 10 to 15 μm, a glass transition temperature of 300 ° C. or more, a thermal expansion coefficient of 25 ppm / ° C. or less, and a wavelength of 550 nm in a range of 100 to 300 ° C. It can be provided as a transparent polyimide film having a transmittance at 85% or more and a yellow index (YI) at 550 nm wavelength of 7 or less.

Therefore, the polyimide film prepared according to the present invention satisfies transparency, resin stability, high heat resistance, low coefficient of thermal expansion and mechanical properties, and thus displays for OLEDs, displays for liquid crystal devices, TFT substrates, flexible printed circuit boards, and flexible OLEDs. It can be widely applied to substrates for flexible displays, such as surface lighting substrates, substrate materials for electronic paper, and protective films.

Claims (9)

1. In the polyimide precursor resin composition containing an aromatic diamine component, an acid dianhydride compound, and an organic solvent,

   The aromatic diamine component (A) is 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (TFMB) which is a fluorinated aromatic diamine monomer, or N- (which is a polyamine monomer having an amide group. 4-amino phenyl) -4-aminobenzamide (DBA), or mixtures thereof,

   The acid dianhydride compound (B) is 4,4- (hexafluoroisopropylidene) diphthalic anhydride (6FDA) which is a fluorinated aromatic acid dianhydride and pyromellitic dianhydride (PMDA) which is a non-fluorinated aromatic acid dianhydride, or 3 A mixture comprising 3,4,4'-biphenyltetracarboxylic dianhydride (BPDA),

   The organic solvent (C) is a mixture of gamma-butyrolactone (GBL) and N-methyl-2-pyrrolidone (NMP), or gamma-butyrolactone (GBL) and 3-methoxy-N, N- A transparent polyimide precursor resin composition having improved resin stability and high heat resistance, which is a mixture of dimethyl propanamide (DMPA) or 3-methoxy-N, N-dimethyl propanamide (DMPA) alone.
2. The method of claim 1, wherein the aromatic diamine component (A)

   2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (TFMB) is 30-100 mol% with respect to the total polyamine compound,

   N- (4-amino phenyl) -4-aminobenzamide (DBA) is 5-50 mol% with respect to the total polyamine compound,

   Transparent polyimide precursor resin composition with improved resin stability, high heat resistance further comprises a residual amount of non-fluorinated aromatic diamine.
3. The compound of claim 1, wherein the acid dianhydride compound (B)

   Fluorinated aromatic acid dianhydrides are 20-80 mol% relative to the total acid dianhydride compounds,

   Non-fluorinated aromatic acid dianhydride is a transparent polyimide precursor resin composition with improved resin stability, high heat resistance, characterized in that 80 to 20 mol% relative to the total acid dianhydride compound.
4. The method of claim 1, wherein the organic solvent (C) is

   Gamma-butyrolactone (GBL) to 30 to 70 mole percent N-methyl-2-pyrrolidone (NMP) or 3-methoxy-N, N-dimethyl propanamide (DMPA) 70 to 30 mole percent Transparent polyimide precursor resin composition which improved resin stability and high heat resistance.
5. The method of claim 1, wherein the polyimide composition further comprises at least one reaction catalyst (D) selected from the group consisting of trimethylamine, xylene, pyridine, and quinoline. A transparent polyimide precursor resin composition having improved resin stability and high heat resistance.
6. A method for producing a transparent polyimide resin film, characterized in that the polyamic acid solution prepared using the composition of any one of claims 1 to 5 is heat-treated to produce a film.
7. The method of claim 6, wherein the polyamic acid solution is prepared by mixing an organic solvent content based on a solid content of 10 to 40wt%, and mixing 95 to 100 mol% of an aromatic diamine component and 100 to 105 mol% of an acid dianhydride compound. The manufacturing method of the transparent polyimide resin film characterized by the above-mentioned.
8. 7. The method of claim 6, wherein the polyamic acid solution is 1000 to 7000 cP.
9. According to the method of claim 6, the film has a glass transition temperature of 300 ° C. or higher, a thermal expansion coefficient of 25 ppm / ° C. or lower, and a transmittance of 550 nm at a wavelength of 10 to 15 μm. Yellow color (Yellow Index, YI) in a wavelength of 550 nm or more is 7 or less, The transparent polyimide resin film characterized by the above-mentioned.

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