KR101899902B1 - Transparent polyimide precursor resin composition improving stability of resin and heat-resistance, method for manufacturing polyimide film using the same, and polyimide film thereof - Google Patents

Abstract

The present invention relates to an aromatic diamine compound and an acid dianhydride for improving heat resistance and mechanical properties and an organic solvent free from white turbidity, A transparent polyamic acid precursor resin composition, a method for producing a polyimide film using the same, and a polyimide film produced thereby.

Description

The present invention relates to a polyimide precursor resin composition which is improved in resin stability and heat resistance and has transparency, a method for producing a polyimide film using the same, and a polyimide film prepared by the method polyimide film using the same, and polyimide film thereof]

The present invention relates to a polyimide precursor resin composition having transparency which has excellent mechanical properties, high heat resistance and low thermal expansion coefficient and does not cause whitening during solution casting, a process for producing a polyimide film using the polyimide precursor resin composition and a polyimide film And can be utilized for a flexible display substrate material and a semiconductor material.

Flexible polymer materials are attracting attention as substrate materials for flexible displays, which are gaining popularity as a next-generation display device.

Flexible devices typically use organic light emitting diode (OLED) displays, and TFT processes at high process temperatures (300-500 ° C) are used. Polymer materials that can withstand such high process temperatures are extremely limited, and among them, polyimide (PI) resin, which is a polymer having excellent heat resistance, is mainly used.

Organic light-emitting diode (OLED) displays are manufactured by applying a resin to a glass substrate, thermally curing the film to form a film, and then removing the glass substrate from the glass substrate after several steps. The resin stability at room temperature is important when the resin is applied to the glass substrate during the manufacturing process. If the stability of the resin is not ensured, a uniform film can not be formed after curing due to resin lump or clouding phenomenon, resulting in product defects. In addition, a product defect may occur due to a thermal shock due to a high temperature of a TFT deposition process in a 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 polyamic acid solution that can be applied as a substrate layer or a protective layer of a display device because of its excellent thermal properties at a low thermal expansion rate and a high thermal decomposition temperature, Can not be secured and a uniform film can not be formed after the curing due to resin lump or clouding phenomenon, resulting in product defects.

Korean Patent Laid-Open Publication No. 2013-35691 discloses a composition and a manufacturing method for producing a copolymerized polyamide-imide film, but it requires a process for producing and removing by-products, which limits the economical part of the process .

Therefore, there is a need to provide a polyimide composition having a high heat resistance, a low thermal expansion coefficient and an excellent mechanical strength as well as the stability of the resin and a manufacturing method which is comparatively simple.

1: Korea Patent Publication No. 2015-108812 2: Korea Patent Publication No. 2013-35691

Accordingly, in order to solve the above problems, the inventors of the present invention have found that, in producing a polyimide film having improved heat resistance and optimal mechanical properties, the composition of aromatic diamine and acid dianhydride and the composition of an organic solvent And discovered a polyimide precursor resin composition having transparency, resin stability, high heat resistance and low thermal expansion coefficient than conventional polyimide films, thereby completing the present invention.

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

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

The present invention also relates to a method for producing a film having a thickness of 10 to 15 탆 and a thermal expansion coefficient of 25 ppm / 캜 or less at a glass transition temperature of 300 캜 or more and 100 to 300 캜, And has a transmittance of 85% or more and a yellow index (YI) at a wavelength of 550 nm of 7 or less.

The present invention relates to 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 a 2,2'-bis (trifluoromethyl) fluorinated aromatic diamine monomer, -4,4'-diaminobiphenyl (TFMB), or N- (4-aminophenyl) -4-aminobenzamide (DBA) which is a diamine monomer having an amide group, or a mixture thereof, The dianhydride compound (B) can be prepared by reacting 4,4 '- (hexafluoroisopropylidene) diphthalic anhydride (6FDA), which is a fluorinated aromatic acid dianhydride, with pyromellitic dianhydride (PMDA) , And 4,4'-biphenyltetracarboxylic acid dianhydride (BPDA), and the organic solvent (C) is a mixture comprising gamma-butyrolactone (GBL) and N-methyl-2-pyrrolidone ) Or a mixture of gamma-butyrolactone (GBL) and 3-methoxy-N, N-dimethylpropane DE 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.

Also, the present invention provides a method for producing a transparent polyimide resin film, wherein the polyamic acid solution prepared by using the composition is heat treated to be a film.

The present invention also relates to a method for producing a film having a thickness of 10 to 15 탆 and a thermal expansion coefficient of 25 ppm / 캜 or less at a glass transition temperature of 300 캜 or more and 100 to 300 캜, A transparent polyimide resin film having a transmittance of 85% or more and a yellow index (YI) at a wavelength of 550 nm of 7 or less.

According to the present invention, resin stability at room temperature, which does not cause whitening during solution casting, is superior to that of conventional polyamic acid solutions, and transparency, excellent mechanical properties, optical characteristics, and heat resistance characteristics Thus, it can be utilized for a flexible display substrate material, a semiconductor material, and the like.

In addition, the present invention does not involve the production and removal of byproducts as compared with the prior art in the production of the polyamic acid solution, so that it is possible to ensure competitiveness in the process.

1 shows the clouding phenomenon (room temperature stability) according to the organic solvent (GBL: NMP = 70 mol%: 30 mol%) of Example 1 when the polyamic acid solution was cast on a glass substrate at room temperature.
2 shows the clouding phenomenon (room temperature stability) according to the organic solvent (GBL: DMPA = 70 mol%: 30 mol%) of Example 2 when the polyamic acid solution was cast on the glass substrate at room temperature.
3 shows the clouding phenomenon (room temperature stability) according to the organic solvent (100 mol% of NMP alone) of Comparative Example 3 when the polyamic acid solution was cast on the glass substrate at room temperature.

The polyimide precursor resin composition of the present invention (hereinafter referred to as " polyamic acid composition ") has a composition of aromatic diamine and acid dianhydride having improved heat resistance and having optimum mechanical properties, composition of organic solvent And a transparent polyimide film having a high heat resistance, a low thermal expansion coefficient, and an excellent mechanical strength by optimizing the amount of the polyimide film and the amount thereof used. The polyimide precursor composition according to the present invention, that is, the 'polyamic acid composition' refers to a composition used for producing a polyamic acid solution used for producing a polyimide film.

Specifically, the polyamic acid composition according to the present invention comprises a diamine compound having a fluorinated aromatic diamine or an amide group, or an aromatic diamine component (A) containing a mixture thereof, an acid containing a fluorinated aromatic acid dianhydride and a non-fluorinated aromatic acid dianhydride compound The dianhydride compound (B), gamma -butyrolactone (GBL) is dissolved in an organic solvent containing N-methyl-2-pyrrolidone (NMP) or 3-methoxy-N, N-dimethylpropanamide (DMPA) C), and a reaction catalyst (D). Each component will be described in detail as follows.

(A) an aromatic diamine component

In the present invention, the aromatic diamine component may be an aromatic diamine monomer such as 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (TFMB), or a diamine monomer having an amide group, such as N- 4-aminophenyl) -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, (4-aminophenyl) -4-aminobenzamide (DBA) in an amount of 5 to 50 mol% based on the total diamine compound, and may further include a residual amount of a non-fluorinated aromatic diamine.

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

In addition, when N- (4-aminophenyl) -4-aminobenzamide (DBA) is mixed with such a fluorinated aromatic diamine, a polyimide film having excellent heat resistance and low thermal expansion coefficient due to rigidity of aromatic structure and amide structure Can be provided.

When a fluorinated aromatic diamine and an N- (4-aminophenyl) -4-aminobenzamide are mixed with an aromatic diamine component, a polyimide film having improved optical characteristics and optical characteristics at the same time as compared with the case of using only a 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 (TFMB), bisaminohydrofuran Bis aminophenoxyphenyl hexafluoropropane (4BDAF), 2,2'-bis (trifluoromethyl) -4,3'-diazoacetate, bisaminophenoxyphenyl hexafluoropropane Bis (trifluoromethyl) -4,3'-diaminobiphenyl, and 2,2'-bis (trifluoromethyl) -5,5'-diaminobiphenyl (2,2 ' -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.

When the TFMB is used within the range of 30 to 100 mol%, preferably 50 to 90 mol%, based on 100 mol% of the total diamine compound, the charge transfer effect (charge transfer effect ) Can further improve the optical characteristics of the polyimide film.

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

On the other hand, the polyimide resin may include a compound capable of forming or forming an amide structure for excellent heat resistance and low thermal expansion coefficient. Examples of the compound capable of forming such an amide structure include an acid halide and a dicarboxylic acid. For example, p-terephthaloyl chloride (TPC), isophthaloyl dichloride (IPC), 1,3-adamantanedicarbonyl dichloride (ADC) 5-norbornene-2,3-dicarbonyl chloride (NDC), 4,4'-benzoyl dichloride (BDC), 1 4-naphthalene dicarboxylic acid dichloride (1,4-NaDC), 2,6-naphthalene dicarboxylic acid dichloride (2, 4-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). At least one selected from the group consisting of

However, such compounds may form by-products such as HCl and H ₂ O while forming an amide structure, and may deteriorate the film properties in the production of an imide film.

Therefore, in the present invention, it is possible to use a compound containing N- (4-aminophenyl) -4-aminobenzamide (DBA), which is a diamine compound having an amide group, An amide group can be introduced into the chain to realize the heat resistance characteristic and the low thermal expansion coefficient characteristic. The content of N- (4-aminophenyl) -4-aminobenzamide (DBA) is not particularly limited, but is preferably 5 to 50 mol%, more preferably 5 to 20 mol%, based on 100 mol% .

(B) an acid dianhydride compound

The aromatic acid dianhydride compound of the present invention comprises 20 to 80 mol% of a fluorinated aromatic acid dianhydride and 80 to 20 mol% of a non-fluorinated aromatic acid dianhydride compound.

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

The fluorinated aromatic dianhydride is an aromatic acid dianhydride to which a fluorine substituent has been introduced, and examples thereof include 4,4 '- (hexafluoroisopropylidene) diphthalic anhydride (4,4' - (Hexafluoroisopropylidene) diphthalic anhydride, ), And 4,4 '- (4,4'-hexafluoroisopropylidene diphenoxy) bis- (4,4'- (4,4'-Hexafluoroisopropylidenediphenoxy) bis- (phthalic anhydride , 6-FDPDA). In the present invention, 6FDA is preferably used as the fluorinated aromatic acid dianhydride.

Such a fluorinated aromatic dianhydride is 20 to 80 mol%, preferably 40 to 70 mol% based on 100 mol% of the total amount of the acid dianhydride, and can realize the high transmittance and low yellowing degree 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, such as pyromellitic dianhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic acid 3,3'4,4'-biphenyltetracarboxylic acid dianhydride (BPDA), 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride (3,3', 4,4'-benzophenonetetracarboxylic acid 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'-diphenylsulfone tetracarboxylic acid anhydride (3,3', 4,4'- tetragarboxylic dianhydride (DSDA), ethylene glycol bis (4-trimellitate anhydride) and TMEG. However, in the present invention, Preferably PMDA or BPDA or a mixture thereof is used as the non-fluorinated aromatic acid dianhydride.

At this time, the non-fluorinated aromatic dianhydride is 80 to 20 mol%, preferably 30 to 50 mol% based on 100 mol% of the total amount of the acid dianhydride, and the polyimide film has heat resistance Can be lowered.

(C) an organic solvent

The organic solvent in the present invention may be an organic solvent such as m-cresol, N-methyl-2-pyrrolidone (NMP), N, N-dimethylformamide (DMF), dimethylacetamide (DMAc), dimethylsulfoxide A polar solvent such as ethyl acetate (DEA), 3-methoxy-N, N-dimethylpropanamide (DMPA) or the like, a low boiling solvent such as tetrahydrofuran (THF), chloroform, or the like such as gamma-butyrolactone and GBL There is a low-sorption solvent.

The organic solvent used in the present invention plays an important role in the improvement of the whitening phenomenon, wherein the whitening phenomenon can be confirmed through FIG. 1 to FIG. FIG. 1 shows stability at room temperature (no clouding) of an organic solvent of 70 mol% of GBL and 30 mol% of NMP upon casting a polyamic acid solution onto a glass substrate at room temperature. FIG. % Of an organic solvent at room temperature (no clouding phenomenon). On the other hand, FIG. 3 shows a whitening phenomenon with respect to an organic solvent of 100 mol% of NMP alone.

Therefore, in the present invention, a mixture of gamma-butyrolactone (GBL) and N-methyl-2-pyrrolidone (NMP) or gamma-butyrolactone (GBL) And a mixture of 3-methoxy-N, N-dimethylpropanamide (DMPA) or 3-methoxy-N, N-dimethylpropanamide (DMPA) alone.

In this case, the amount of the organic solvent to be used is 30 to 70 mol% of gamma-butyrolactone (GBL), 70 to 70 mol% of N-methyl-2-pyrrolidone (NMP) 30 mol% is preferably used. More preferably, 30 to 50 moles of N-methyl-2-pyrrolidone (NMP) or 3-methoxy-N, N-dimethylpropanamide (DMPA) is added to 50 to 70 mol% of gamma-butyrolactone %to be. Or gamma-butyrolactone (GBL) alone may be used.

(D) Reaction Catalyst

The reaction catalyst of the present invention may further include at least one member selected from the group consisting of trimethylamine, xylene, pyridine and quinoline according to reactivity, . 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 not significantly impairing the objects and effects of the present invention.

In addition, the polyamic acid solution obtained by polymerization using the aromatic diamine component, the acid dianhydride compound, the organic solvent, and the reaction catalyst, which is the polyamic acid composition according to the present invention, has a solid content of 10 to 40 wt% Preferably 10 to 25% by weight. When the solid content is less than 10% by weight, there is a limit to increase the thickness of the film in the production of the film. When the solid content is more than 40% by weight, the viscosity of the polyamic acid resin is limited.

Specifically, the polyamic acid solution is used in an organic solvent content based on a solid content of 10 to 40 wt%, and 100 molar parts of an aromatic diamine component and 95 to 105 molar parts of an acid dianhydride compound are mixed and reacted at 24 to 48 Lt; / RTI > hours. The reaction temperature may vary depending on the monomers used.

Here, it is preferable to add an acid dianhydride compound in an amount of -5 to 5 parts by mol relative to the aromatic diamine component so as to reach a target viscosity, for the reason 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. When the viscosity is less than 1,000 cP, there is a problem in obtaining an appropriate level of film thickness. When the viscosity is more than 7,000 cP, the uniform coating and effective solvent removal are problematic.

In addition, the transparent polyimide film and the method for producing the transparent polyimide film of the present invention are as follows. The present invention provides a transparent polyimide film prepared by thermally modifying a polyamic acid solution prepared by the above-described polyamic acid composition. The polyamic acid solution according to the present invention has viscosity and is prepared by coating the glass substrate with a suitable method and then heat-treating the film. The coating method can be applied by any conventional method without limitation including spin coating, dip coating, solvent casting, slot die coating, spray coating, ), But the present invention is not limited thereto.

The polyamic acid composition of the present invention can be made into a polyimide film by heat treatment in a high temperature convection oven. At this time, the heat treatment is performed under a nitrogen atmosphere, and the heat treatment is performed at 100 to 450 ° C for 30 to 120 minutes. More preferably, the film is preferably obtained under the conditions of a temperature and a time of 100 占 폚 / 30min, 220 占 폚 / 30min, 350 占 폚 / 30min. This is because of the imidization that can maximize the removal and characterization of suitable solvents.

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

The polyimide film of the present invention has a film thickness of 10 to 15 占 퐉, a glass transition temperature of 300 占 폚 or more, and a thermal expansion coefficient of 25 ppm / 占 폚 or less, preferably 15 ppm / 占 폚 or less , The transmittance at a wavelength of 550 nm is as high as 85% or more, and the yellow index (YI) at a wavelength of 550 nm is as low as 7 or less, preferably as low as 5 or less. The polyimide film of the present invention can suppress defects of the element on the substrate due to expansion and contraction. In addition, the polyimide film of the present invention has high light transmittance and low yellowing property and can be applied to a flexible display.

The polyimide film of the present invention can be used in a variety of fields, and in particular, it can be used for OLED displays, liquid crystal device displays, TFT substrates, flexible printed circuit boards, flexible OLED surface light substrates, And can be provided as a substrate and a protective film for a flexible display such as a substrate material for use.

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

Comparative Example  One

As a composition shown in Table 1, 2.547 g (0.024 mole) of PPD as a diamine monomer and 17.606 g (0.055 mole) of TFMB were dissolved in 142.1 g of NMP as an organic solvent and 58.5 g of GBL, and the mixture was stirred at room temperature for 30 minutes to 1 hour Lt; / RTI > 24.798g (0.056mole) of 6FDA and 5.212g (0.024mol) of PMDA were added, followed by polymerization for 24 hours, followed by addition of 83.6g of GBL and stirring for 24 hours to prepare a polyamic acid solution (reaction temperature: 30 Lt; 0 > C, where the solid content is maintained at 15 wt% based on the total weight of the reaction solvent. The viscosity was measured with a Brookfield DV2T, SC4-27 viscometer and found to be 5,700 cP.

Comparative Example  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 in Table 1 was used.

Example  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 in Table 1 was used.

Experimental Example 1: Property  Measure

(1) Evaluation of cloudiness at room temperature

The polyamic acid solution prepared in Examples 1 to 5 and Comparative Examples 1 to 3 was prepared and placed on a glass plate. Using a bar coater, a certain thickness (15 탆 after heat treatment when the solution thickness was 100 탆 based on 15% solids) After standing for 30 minutes in an atmosphere of a temperature of 25 DEG C and a humidity of > 90%, a whitening phenomenon was observed. The level of cloudiness was assessed from 0 to 5 (0: no occurrence, 5: severe occurrence).

(2) Film production 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 was conducted under a nitrogen atmosphere, and the final film was obtained under the conditions of 100 ° C./30 min., 220 ° C./30 min. And 350 ° C./30 min. The film thus obtained was measured for physical properties as described below, and the results are shown in Table 2 below.

(a) Transmittance and retardation

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

(b) Yellowness Index (YI)

And measured using a color difference meter (LabScan XE).

(c) turbidity (haze)

And measured using a haze meter (TOYOSEIKI, HAZE-GARD).

(d) Thermal properties

The glass transition temperature (T _g ) and the thermal expansion coefficient (CTE) of the film were measured using TMA 402 F3 from Netzsch. The force in the tension mode was set to 0.05 N, and the measured temperature was raised 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 a range of 100 to 300 ° C. The pyrolysis temperature (T _d , 1%) was measured using TG 209 F3 from Netzsch.

(e) mechanical properties

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

division Example 1 Example 2 Example 3 Example 4 Example
5 Comparative Example
One Comparative Example
2 Comparative Example
3 Composition Acid anhydride (unit: mol%) 6FDA / PMDA = 70: 30 Diamine (unit: mol%) TFMB / PPD = 70: 30 abandonment
Solvent mixture 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)
* PPD: para-phenylenediamine (p-Phenylene diamine)
NMP: N-methyl-2-pyrrolidone (N-methyl-2-pyrrolidone)
* GBL: gamma-butyrolactone (gamma-butyrolactone)
DMPA: 3-methoxy-N, N-dimethyl propanamide. Properties
Measure Viscosity (cP, 23 캜) 6400 6000 5800 5600 5600 5700 5300 5000 Turbidity level
(Room temperature, RH > 90%) 0 0 0 0 0 One 2 5 Thickness (㎛) 11 12 11 13 11 10 12 11 Transmittance (%, @ 550 nm) 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 (占 폚) 351 348 347 351 352 355 350 355 Td 1% (占 폚) 458 448 452 455 463 453 463 466 CTE
(100 to 300 ° C / ppm / ° C) 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, in which organic solvents GBL and NMP were used in a predetermined ratio of 70:30 (mol%), no clouding occurred during solution casting on the glass plate, .

Also, it can be seen that the whitening phenomenon does not occur even when GBL and DMPA are mixed as in Examples 2 to 4, or when DMPA alone is used as in Example 5.

This is because the water absorption rate of GBL is low and it is effective to control the occurrence of opacity as the content of GBL increases. And DMPA is also effective in inhibiting opacification in the same context. In addition, the optical characteristics, thermal properties, and mechanical properties of the film are comparable to those of Comparative Examples 1 to 3.

From these results, it can be seen that when GBL, NMP, GBL and DMPA are used in predetermined amounts as the organic solvent content according to the present invention, resin stability at room temperature can be secured without deteriorating the film properties.

Comparative Example  4

As the composition shown in Table 2, 21.186 g (0.066 mole) of TFMB as a diamine monomer was dissolved in 86.7 g of NMP as an organic solvent and 117.3 g of GBL and dissolved in a nitrogen atmosphere at room temperature for 30 minutes to 1 hour. Then, 29.881 g (0.067 mole) of dianhydride monomer, 0.067 mole, was added and polymerization was carried out for 24 hours. Further, 85.0 g of GBL was added and stirred for 24 hours to prepare a polyamic acid solution (reaction temperature: 30 ° C, The viscosity was measured with a Brookfield DV2T, SC4-27, and the viscosity was 4,200 cP.

Example  6

As a composition shown in Table 2, 2.589 g (0.024 mole) of PPD as a diamine monomer and 17.899 g (0.056 mole) of TFMB were dissolved in 86.7 g of NMP as an organic solvent and 117.3 g of GBL, and the mixture was stirred at room temperature for 30 minutes to 1 hour Lt; / RTI > Then 25.210 g (0.057 mole) of dianhydride monomer and 5.299 g (0.024 mol) of PMDA were added and polymerization was carried out for 24 hours. Then 85.0 g of GBL was added and stirred for 24 hours to prepare a polyamic acid solution (reaction temperature: ° C., where the solids content is maintained at 15% by weight based on the total weight of the reaction solvent.) Viscosity was measured to be 6,400 cP as measured by a viscosity measuring instrument (Brookfield DV2T, SC4-27).

Example  7

As the composition shown in Table 2, 22.244 g (0.069 mole) of TFMB as a diamine monomer and 0.842 g (0.004 mol) of DBA were dissolved in 86.7 g of NMP as an organic solvent and 117.3 g of GBL, and the mixture was stirred at room temperature for 30 minutes to 1 hour Lt; / RTI > 23.063 g (0.052 mole) of 6FDA monomer and 4.848 g (0.022 mol) of PMDA were added to the mixture, and the mixture was polymerized for 24 hours. 85.0 g of GBL was further added thereto and stirred for 24 hours to prepare a polyamic acid solution (reaction temperature: ° C., where the solid content is maintained at 15% by weight with respect to the total weight of the reaction solvent.) Viscosity was measured to be 4,800 cP by means of a viscometer (Brookfield DV2T, SC4-27).

Example  8

As the composition shown in Table 2, 24.320 g (0.076 mole) of a diamine-based monomer TFMB was dissolved in 86.7 g of NMP as an organic solvent and 117.3 g of GBL and dissolved in a nitrogen atmosphere at room temperature for 30 minutes to 1 hour. Then, 17.110 g (0.038 mole) of 6FDA, which is a dianhydride monomer, and 5.035 g (0.038 mol) of PMDA were added and polymerized for 24 hours. Then, 85.0 g of GBL was further added thereto and stirred for 24 hours to prepare a polyamic acid solution ° C., where the solids content is maintained at 15% by weight based on the total weight of the reaction solvent.) Viscosity was measured to be 6,600 cP as measured by a viscosity measuring instrument (Brookfield DV2T, SC4-27).

Example  9

2.094 g (0.019 mole) of PPD as a diamine monomer, 18.610 g (0.058 mole) of TFMB and 0.881 g (0.004 mol) of DBA were dissolved in 86.7 g of NMP as an organic solvent and 117.3 g of GBL, , And dissolved at room temperature for 30 minutes to 1 hour. 24.298g (0.055mole) of 6FDA and 5.115g (0.023mol) of PMDA were added, followed by polymerization for 24 hours, followed by addition of 85.0 g of GBL and stirring for 24 hours to prepare a polyamic acid solution (reaction temperature: 30 ° C, where the solids content is maintained at 15% by weight based on the total weight of the reaction solvent.) Viscosity was measured to be 6,800 cP by Brookfield DV2T, SC4-27

Experimental Example 2: Properties  Measure

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

division Example 6 Example 7 Example 8 Example 9 Comparative Example 4 Composition Acid anhydride 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)
* PPD: para-phenylenediamine (p-Phenylene diamine)
DBA: N- (4-aminophenyl) -4-aminobenzamide N-
NMP: N-methyl-2-pyrrolidone (N-methyl-2-pyrrolidone)
* GBL: gamma-butyrolactone (gamma-butyrolactone) Properties
Measure Viscosity (cP, 23 캜) 6400 4800 6600 6800 4200 Cloudiness level (room temperature, RH> 90%) 0 0 0 0 0 Thickness (㎛) 11 11 13 10 12 Transmittance (%, @ 550 nm) 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 (占 폚) 351 360 355 349 278 Td 1% (占 폚) 458 463 481 466 407 CTE
(100 to 300 ° C / ppm / ° C) 14 10 11 9 34 Tensile strength (MPa) 130 120 125 115 120 Elongation (%) 17 15 22 15 10

As shown in Table 2, it can be seen that, in Examples 6 to 8, as the content of acid dianhydride monomers such as PMDA and BPDA and the diamine monomers PPD and DBA increases, the thermal characteristics are improved while exhibiting high permeability. In addition, in Example 9 using TFMB, PPD, and DBA as diamine monomers, DBA can realize heat resistance and low thermal expansion coefficient without producing any byproducts.

Thus, the polyamic acid solution prepared according to the present invention has a film thickness of 10 to 15 占 퐉, a glass transition temperature of 300 占 폚 or higher, a thermal expansion coefficient of 100 ppm to 300 占 폚, Can be provided as a transparent polyimide film having a transmittance of 85% or more at a wavelength of 550 nm and a yellow index (YI) of 7 or less at a wavelength of 550 nm.

Accordingly, the polyimide film produced according to the present invention satisfies transparency, resin stability, high heat resistance, low thermal expansion coefficient, and mechanical properties, and is therefore suitable for OLED display, liquid crystal display, TFT substrate, flexible printed circuit board, flexible OLED And can be widely applied to a substrate and a protective film for a flexible display such as a planar illumination substrate and a substrate material for an electron species.

Claims (10)

A polyimide precursor resin composition comprising an aromatic diamine component, an acid dianhydride compound, and an organic solvent,
The aromatic diamine component (A) can be prepared by reacting 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (TFMB), which is a fluorinated aromatic diamine monomer, and N- - < / RTI > aminophenyl) -4-aminobenzamide (DBA)
The acid dianhydride compound (B) can be obtained by reacting 4,4 '- (hexafluoroisopropylidene) diphthalic anhydride (6FDA), which is a fluorinated aromatic acid dianhydride, with pyromellitic dianhydride (PMDA), which is a nonfluorinated aromatic acid dianhydride, 3,3,4,4'-biphenyl tetracarboxylic acid dianhydride (BPDA)
The organic solvent (C) may be a mixture of gamma-butyrolactone (GBL) and 3-methoxy-N, N-dimethylpropanamide (DMPA) or a mixture of 3-methoxy-N, N-dimethylpropanamide ) Alone. The transparent polyimide precursor resin composition of claim 1,
The aromatic diamine component (A) according to claim 1, wherein the aromatic diamine component
(A-1) 100 mol% of TFMB;
(A-2) 30 to 95 mol% of TFMB and 5 to 50 mol% of DBA;
(A-3) further comprises a residual amount of a non-fluorinated aromatic diamine in the (A-2) so that the aromatic diamine component (A) is 100 mol% Mid precursor resin composition
The method according to claim 1, wherein the acid dianhydride compound (B)
The fluorinated aromatic acid dianhydride is 20 to 80 mol% based on the total acid dianhydride compound,
A transparent polyimide precursor resin composition having improved resin stability and high heat resistance, wherein the non-fluorinated aromatic acid dianhydride is 80 to 20 mol% based on the total acid dianhydride compound.
The method according to claim 1, wherein the organic solvent (C)
A transparent polyimide precursor having improved resin stability and high heat resistance, characterized by comprising 30 to 70 mol% of gamma-butyrolactone (GBL) and 70 to 30 mol% of 3-methoxy-N, N-dimethylpropanamide (DMPA) Resin composition.
The polyimide precursor resin composition according to claim 1, wherein the polyimide precursor resin composition further comprises at least one reaction catalyst (D) selected from the group consisting of trimethylamine, xylene, pyridine, and quinoline The transparent polyimide precursor resin composition according to claim 1,
A process for producing a transparent polyimide resin film, characterized in that the polyamic acid solution prepared by using the composition of any one of claims 1 to 5 is heat treated to produce a film.
[7] The method according to claim 6, wherein the polyamic acid solution is prepared by mixing an aromatic diamine component (100 moles) and an acid dianhydride compound (95-105 moles) in an organic solvent content of 10 to 40 wt% A method for producing a polyimide resin film.
The method for producing a transparent polyimide resin film according to claim 6, wherein the polyamic acid solution has a viscosity of 1000 to 7000 cP.
A film produced by the method of claim 6 has a glass transition temperature of 300 ° C or higher, a thermal expansion coefficient of 25 ppm / ° C or lower in a range of 100 to 300 ° C, a transmittance at a wavelength of 550 nm of 85 % Or more, and a yellow index (YI) at a wavelength of 550 nm is 7 or less. A polyimide precursor resin composition comprising an aromatic diamine component, an acid dianhydride compound, and an organic solvent,
The aromatic diamine component (A) can be prepared by reacting 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (TFMB), which is a fluorinated aromatic diamine monomer, and N- - < / RTI > aminophenyl) -4-aminobenzamide (DBA)
The acid dianhydride compound (B) can be obtained by reacting 4,4 '- (hexafluoroisopropylidene) diphthalic anhydride (6FDA), which is a fluorinated aromatic acid dianhydride, with pyromellitic dianhydride (PMDA), which is a nonfluorinated aromatic acid dianhydride, 3,3,4,4'-biphenyl tetracarboxylic acid dianhydride (BPDA)
The organic solvent (C) is a mixture of gamma-butyrolactone (GBL) and N-methyl-2-pyrrolidone (NMP)
A transparent polyimide precursor resin composition having improved resin stability and high heat resistance, which comprises 30 to 70 mol% of gamma-butyrolactone (GBL) and 70 to 30 mol% of N-methyl-2-pyrrolidone (NMP).

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