KR20170076114A - Polyamic acid composition comprising novel anhydride monomer and trasparent polyimide film using the same - Google Patents

Abstract

The present invention provides novel monomers to which an acid dianhydride of polyamic acid can be applied, a polyamic acid composition containing the same, and a polyimide prepared from the composition.
Since the polyamic acid composition of the present invention has a high glass transition temperature and low yellowing degree and excellent mechanical properties, the polyimide prepared from the polyimic acid composition can be usefully used as a material for a flexible display.

Description

TECHNICAL FIELD The present invention relates to a polyamic acid solution to which an acid anhydride monomer is applied and a polyimide film containing the acidic dianhydride monomer.

The present invention relates to a polyamic acid composition for producing a transparent polyimide resin comprising a novel structure of anhydride monomer, an acid anhydride monomer, and a transparent polyimide resin prepared from the composition and applicable as a flexible display substrate or a protective film .

As the flat panel display (FPD) has become thinner and smaller, a transparent plastic substrate is required instead of a glass substrate in manufacturing a flat panel display.

In accordance with this demand, a transparent plastic substrate made by polymerizing a polymer resin such as polyethylene terephthalate (PET) or polyether sulfone (PES) has been developed. The transparent plastic substrate using a polymer resin such as PET or PES has a ductility lower than that of a glass substrate, but has a low glass transition temperature (Tg), thereby deteriorating heat resistance. In addition, since the coefficient of thermal expansion (CTE) of the glass substrate is higher than that of the glass substrate, there is a problem that deformation is easily caused by a process (for example, a TFT process at 220 캜 or more) at a high temperature during a display manufacturing process.

On the other hand, a technique for producing a transparent plastic substrate using a polyimide resin having excellent heat resistance and a relatively low coefficient of thermal expansion has attracted attention. The polyimide resin (PI) is colored to brown or yellow due to the effect of a change transfer complex (CTC) and has a low transparency in the visible light region, . Therefore, many studies are under way to solve these problems. Generally, a polyimide (PI) resin refers to a high heat resistant resin prepared by preparing a polyamic acid derivative by combining an aromatic dianhydride, an aromatic diamine or an aromatic diisocyanate in solution, and then dehydrating and cyclizing at a high temperature to imidize it.

(PMDA), biphenyltetracarboxylic acid dianhydride (BPDA) and the like are used as the components of the aromatic acid dianhydride for producing the polyimide resin, and as the aromatic diamine component, oxydianiline (ODA ), p-phenylenediamine (p-PDA), m-methylenediamine (m-MDA), methylenediamine (MDA) and bisaminophenylhexafluoropropane (HFDA). Since the acid anhydride or diamine component has a trade-off relationship between optical properties, thermal properties and mechanical properties, it is necessary to develop a compound of a component suitable for each property, that is, a monomer for transparent PI, Accordingly, it is required to develop a transparent polyamic acid composition for a flexible display, which exhibits high transparency while exhibiting excellent heat resistance, low thermal expansion coefficient and excellent mechanical properties.

The present invention has been made in view of the fact that introduction of a monomer having a specific chemical structure and a substituent improves optical characteristics, mechanical properties, and thermal properties compared with the conventional ones.

More specifically, a conventional polyimide film has a dark brown color rather than a color due to formation of a charge transfer complex (CTC) of π electrons present in an imide chain. In the present invention, specific substituents of the above-mentioned monomers include -F or -CF ₃ Since a strong Electro Withdrawing group is applied, it is possible to manufacture a colorless transparent PI film by preventing the CT-Complex from occurring due to the movement of the π electron.

Further, in the present invention, it has been considered effective to introduce a monomer having a rigid chemical structure in order to obtain a polyimide resin having excellent mechanical and thermal characteristics. An acid anhydride monomer derivative having a specific chemical structure has been designed and synthesized, A transparent polyamic acid composition and a polyimide film which can simultaneously realize low YI (Yellow Index), high light transmittance, mechanical and thermal characteristics, etc. can be obtained by controlling the content of the novel synthesized acid dianhydride monomer in a specific range The purpose.

In addition, the present invention relates to a transparent polyamic acid which can be applied to plastic transparent substrates for flexible displays of LCDs and OLEDs, TFT substrates, flexible printed circuit boards, flexible OLED surface illuminated substrates, And a transparent polyimide film.

In order to achieve the above object, the present invention provides a compound represented by the following formula (1).

In Formula 1,

A is a single bond or a C ₆ to C ₄₀ arylene group,

X ₁ and X ₂ are the same or different and are each independently selected from the group consisting of hydrogen, halogen, C ₁ -C ₆ alkyl, and C ₁ -C ₆ alkyl substituted with at least one hydrogen,

Provided that when A is a single bond, at least one of X ₁ and X ₂ is a C ₁ -C ₆ alkyl group substituted by a halogen or a halogen atom,

The C ₆ -C ₄₀ arylene group may be substituted with a halogen or a C ₁ -C ₆ alkyl group substituted with a halogen atom, and m is an integer of 0 to 3.

In the present invention, it is preferable that X ₁ and X ₂ are each independently F or an electron attractive group (EWG) which is CF ₃ .

The present invention also relates to a process for the preparation of (a) a diamine; (b) an acid dianhydride containing a compound represented by the above-mentioned formula (1); And (c) an organic solvent, wherein the compound represented by the formula (1) is contained in an amount of 10 to 80 mol% based on 100 mol% of the total acid dianhydride.

In the present invention, the acid dianhydride may include at least one selected from the group consisting of a fluorinated aromatic primary acid dianhydride, an alicyclic secondary acid dianhydride, and a non-fluorinated aromatic dianhydride.

In the present invention, the content of the at least one compound selected from the group consisting of the first acid dianhydride, the second acid dianhydride and the third acid dianhydride may be 20 to 90 mol% based on 100 mol% of the total acid dianhydride.

In the present invention, the diamine is a fluorinated primary diamine; A sulfone-based second diamine, an alicyclic tertiary amine, and an ether-based quaternary amine.

In the present invention, the content of the at least one diamine selected from the group consisting of the first fluorinated diamines, the sulfonic second diamines, the alicyclic tertiary amines and the ether-based fourth amines is preferably from 10 to 100 mol% 100 mole%.

In the present invention, the ratio (a / b) of the number of moles of the diamine (a) to the number of moles of the acid anhydride (b) may range from 0.7 to 1.3.

In addition, the present invention provides a transparent polyimide film prepared by imidizing the above-mentioned polyamic acid composition.

In the present invention, the transparent imide film may satisfy the following physical conditions (i) to (v), and more specifically, (i) the glass transition temperature (T _g ) (iii) a yellowness according to ASTM E313 of 3.3 or less (based on a film thickness of 50 占 퐉); (iv) a tensile strength of 125 to 100 占 퐉; 150 MPa, and (v) the tensile modulus may range from 3.5 to 5.0 GPa.

In the present invention, the transparent imide film can be used as a substrate and a protective film for a flexible display.

In the present invention, it is possible to provide a transparent polyimide composition having excellent optical properties, mechanical properties, and thermal characteristics at the same time by adopting an acid anhydride monomer having a specific structure and a substituent introduced thereinto and adjusting the content thereof to a specific range.

In addition, the present invention can provide a transparent substrate for a flexible display that exhibits excellent physical properties and product reliability by applying the composition for transparent polyimide having excellent optical characteristics, mechanical properties, and thermal properties as a substrate.

Hereinafter, the present invention will be described in detail. However, it should be understood that the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

<Novel acid dianhydride compound>

The present invention provides a compound represented by the following formula (1), preferably a dianhydride compound.

 [Chemical Formula 1]

In Formula 1,

A is a single bond or a C ₆ to C ₄₀ arylene group,

X ₁ and X ₂ are the same or different and are each independently selected from the group consisting of hydrogen, halogen, C ₁ -C ₆ alkyl, and C ₁ -C ₆ alkyl substituted with at least one hydrogen,

Provided that when A is a single bond, at least one of X ₁ and X ₂ is a C ₁ -C ₆ alkyl group substituted by a halogen or a halogen atom,

The C ₆ -C ₄₀ arylene group may be substituted with a halogen or a C ₁ -C ₆ alkyl group substituted with a halogen atom, and m is an integer of 0 to 3.

In the present invention, the compound represented by the formula (1) is similar to the structure of the existing BPDA (3,3 ', 4,4'-biphenyltetracarboxylic dianhydride), but the divalent And has a rigid structure due to the introduction of a divalent arylene linker. Therefore, since it is not decomposed by heat or light and is more stable against external impact, it is possible to significantly improve the optical characteristics, thermal properties, and mechanical properties (modulus, strength) of the polyamic acid composition containing the same.

In the present invention, at least one electron-withdrawing group (EWG) such as fluorine (F) or CF ₃ is introduced into the above-described formula (1) It is possible to increase the above-described optical characteristics and thermal characteristics by preventing the occurrence of complex.

According to a preferred embodiment of the present invention, X ₁ and X ₂ may be a conventional electron withdrawing group (EWG), which is known in the art, and is preferably independently fluorine (F) or CF ₃ .

Further, A may be a conventional C ₆ to C ₄₀ arylene group known in the art, and specific examples thereof include phenylene, biphenylene, triphenylene, and the like. Particularly, it is preferable that A is selected from the group of substituents represented by the following formulas.

,

,

,

,

,

,

,

,

,

,

,

,

In these substituents, R ₁ to R ₃ are the same as or different from each other, and each independently selected from the group consisting of hydrogen, F, and CF ₃ . Preferably, R ₁ to R ₃ are each independently F or CF ₃ .

The compound represented by the formula (1) according to the present invention may be further compounded as a compound group composed of the following compounds 1 to 30, but is not particularly limited thereto.

&Lt; Transparent polyamic acid composition >

The transparent polyamic acid composition of the present invention for producing a transparent polyimide film is characterized in that the compound represented by the formula (1) is contained as a dianhydride component.

More specifically, the polyamic acid composition comprises (a) a diamine; (b) an acid dianhydride containing the compound of Formula 1; And (c) an organic solvent.

The diamine monomer (a) used in the production of the transparent polyamic acid of the present invention may be a conventional diamine known in the art. For example, an aromatic, alicyclic or aliphatic compound having a diamine structure may be used without limitation .

The diamine which can be used in the present invention has a high thermal characteristic such as high transmittance, low YI, low haze, high glass transition temperature (Tg), low thermal expansion coefficient (Low CTE) Considering the mechanical properties such as high modulus and high surface hardness, a proper combination of structures including a linear structure having a fluorinated substituent, a sulfone system, an ether system, need. Accordingly, a fluorinated aromatic first diamine, a sulfonic second diamine, an alicyclic tertiary amine, and an ether-based quaternary amine into which a fluorine substituent has been introduced may be used alone, or a mixture of at least one thereof may be used.

Non-limiting examples of usable diamine monomers (a) include oxydianiline (ODA), 2,2'-bis (trifluoromethyl) -4,4'- diaminobiphenyl (2,2'-TFDB ), 2,2'-bis (trifluoromethyl) -4,3'-diaminobiphenyl, 2,2'-bis (trifluoromethyl) Bis (trifluoromethyl) -5,5'-diaminobiphenyl), 2,2'-bis (trifluoromethyl) -4,4 '-Diaminodiphenyl ether, 6-FODA), bisaminohydroxyphenylhexafluoropropane (DBOH), bisaminophenoxyphenylhexafluoro (2,2'-bis (trifluoromethyl) (4BDAF), bisaminophenoxyphenylpropane (6HMDA), bisaminophenoxy diphenylsulfone (DBSDA), bis (4-aminophenyl) sulfone (4,4'-DDS), bis ) sulfone (3,3'-DDS), sulfonyl deep Talic anhydride (SO ₂ DPA), bis (dicarboxyphenyl) dimethylsilane, or one kind of these addition This mixture of two or more of the like is applicable.

Considering the high transparency, high glass transition temperature, and low yellowing, the first fluorinated diamine is a 2,2'-bis (trifluoromethyl) -4,4'-dia Minobiphenyl (2,2'-TFDB) is preferably used. Further, it is preferable to use bis (4-aminophenyl) sulfone (4,4'-DDS) as the second sulfonic diamine. The ether-based quaternary amine is preferably 2,2'-bis (trifluoromethyl) -4,4'-diaminophenyl ether (6-FODA).

In the diamine monomer (a) of the present invention, the content of the fluorinated first diamine, the sulfonic second diamine, the alicyclic tertiary amine, the ether tertiary amine and the like is not particularly limited, May be 10 to 100 mol%, preferably 10 to 90 mol%, and more preferably 20 to 80 mol%, based on the total amount of the catalyst.

The acid dianhydride (b) monomer used in the production of the transparent polyamic acid of the present invention includes the compound represented by the above formula (1), and the acid such as the usual fluorinated, nonfluorinated, and alicyclic groups known in the art is limited to anhydride Can be mixed together. For example, a fluorinated primary acid dianhydride, an alicyclic secondary dianhydride, a non-fluorinated dianhydride, or a mixture of at least one of these may be used.

In the present invention, the amount of the acid dianhydride monomer represented by the formula (1) is not particularly limited, and may be, for example, 10 to 80 mol%, preferably 20 to 70 mol% based on 100 mol% % &Lt; / RTI &gt;

In the present invention, the first fluorinated acid dianhydride monomer is not particularly limited as long as the aromatic acid into which the fluorine substituent is introduced is an anhydride.

Examples of usable fluorinated primary dianhydrides include 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 6-FDA), 4- (trifluoromethyl) pyromellitic dianhydride (4-TFPMDA), and the like. These may be used alone or in combination of two or more. Among the fluorinated acid dianhydrides, 6-FDA is a very suitable compound for transparency because the property of limiting the formation of molecular transfer chain and intra-molecular charge transfer complex (CTC) is very large.

The alicyclic secondary acid dianhydride which can be used in the present invention is not particularly limited as far as it is a compound having an alicyclic ring other than an aromatic ring in the compound and having an acid anhydride structure.

Examples of the alicyclic secondary dianhydride usable in the present invention include cyclic butane tetracarboxylic dianhydride (CBDA), 1,2,3,4-cyclopentane tetracarboxylic dianhydride (CPDA) , Bicyclo [2,2,2] -7-octene-2,3,5,6-tetracarboxylic acid dianhydride (BCDA), or a mixture of at least one of the foregoing. .

The non-fluorinated acid dianhydride monomer is not particularly limited as long as the non-fluorinated aromatic acid to which no fluorine substituent is introduced is an anhydride.

Non-limiting examples of usable nonfluorinated tertiary acid dianhydride monomers include pyromellitic dianhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (3, 3 ', 4,4'-Biphenyl tetracarboxylic acid dianhydride, BPDA). These may be used alone, or two or more of them may be used in combination.

In the present invention, the content of at least one compound selected from the group consisting of the first acid dianhydride, the second acid dianhydride and the third acid dianhydride is not particularly limited. For example, they may each be from 20 to 90 mol%, preferably from 30 to 80 mol%, based on 100 mol% of the total acid anhydride.

In the transparent polyamic acid composition of the present invention, the ratio (a / b) of the number of moles of the diamine component (a) to the number of moles of the dianhydride component (b) may be 0.7 to 1.3, preferably 0.8 to 1.2 , And more preferably in the range of 0.9 to 1.1.

The solvent (c) contained in the polyamic acid composition of the present invention for solution polymerization of the monomers described above can be used without limitation in the organic solvent known in the art.

Examples of usable solvents include m-cresol, N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethylsulfoxide (DMSO) Acetate, and dimethyl phthalate (DMP) may be used. In addition, a low-boiling solution such as tetrahydrofuran (THF), chloroform or a low-absorbent solvent such as? -Butyrolactone can be used.

Although the content of the solvent is not particularly limited, the content of the solvent for the polymerization (first solvent) may be in the range of 50 to 95% by weight based on the total weight of the polyamic acid composition to obtain the molecular weight and the viscosity of the appropriate polyamic acid solution , Preferably in the range of 70 to 90 wt%, more preferably in the range of 75 to 85 wt%.

The polyamic acid composition of the present invention can be prepared by reacting the aforementioned acid dianhydride and diamine in an organic solvent and then reacting. For example, the diamine (a) and the acid dianhydride (b) may be added in an amount of from about 1 to about 1 to improve the glass transition temperature and yellowing degree, : 1, the transparent polyamic acid composition can be formed.

The composition of the polyamic acid composition is not particularly limited. For example, the composition of the polyamic acid composition may include, for example, 2.5 to 25.0% by weight of anhydride, 2.5 to 25.0% by weight of diamine, and 100% Of an organic solvent. In the polyamic acid composition according to the present invention, the acid anhydride may be in the range of 30 to 70% by weight and the diamine may be in the range of 30 to 70% by weight based on 100% by weight of the solid content, but is not particularly limited thereto.

Such a transparent polyamic acid composition of the present invention may have a viscosity ranging from about 1,000 to 50,000 cps, preferably from about 3,000 to 15,000 cps. When the viscosity of the polyamic acid solution falls within the above-mentioned range, it is easy to control the thickness of the polyamic acid solution coating, and the coating surface can be uniformly exerted.

The polyamic acid solution of the present invention 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 within a range that does not significantly impair the objects and effects of the present invention .

<Polyimide Film>

The present invention provides a polyimide film produced by imidizing and heat-treating the polyamic acid solution described above at a high temperature.

The polyimide resin is a polymer material containing an imide ring and is excellent in heat resistance, chemical resistance, abrasion resistance and electrical properties. The polyimide resin may be in the form of a random copolymer or a block copolymer.

On the other hand, polyimide resin films should have characteristics such as high transparency, low thermal expansion coefficient and high glass transition temperature in order to be applied to flexible displays and the like. More specifically, it has a light transmittance of 75% or more at a film thickness of 10 mu m to 400 nm, a light transmittance at 550 nm of 90% or more, a yellowness value at 550 nm of 3 or less, a glass transition temperature (Tg) Is required.

In fact, the polyimide film prepared by imidizing the polyamic acid composition described above has a rigid chemical structure in the repeating unit, so that the polyimide film exhibits high transparency while exhibiting low yellowing degree, thermal expansion coefficient, high glass transition temperature (Tg), high tensile strength and elastic modulus. More specifically, the polyimide film has the following properties (i) to (T _g ) in the range of 300 to 400 ° C, (ii) a film thickness of 10 to 80 μm (Iv) the tensile strength is 125 to 150 MPa, and (v) the tensile elastic modulus is in the range of 3.5 GPa to 5.0 GPa, and the light transmittance at a wavelength of 500 nm is at least 90%; (iii) the yellowness according to the ASTM E313 standard is 3.3 or less; All can be satisfied.

The polyimide film according to the present invention can be produced by subjecting a transparent polyamic acid solution to an exothermic solution polymerization according to a conventional method known in the art. For example, the transparent polyamic acid composition may be coated (cast) on a glass substrate, and then the imidization may be induced for 0.5 to 8 hours while gradually raising the temperature in the range of 30 to 350 ° C. At this time, the reaction is preferably carried out in an inert atmosphere such as argon or nitrogen.

In this case, the coating method may be any conventional method known in the art. For example, spin coating, dip coating, solvent casting, slot die coating ), And spray coating. &Lt; IMAGE &gt; The transparent polyamic acid composition may be coated one or more times so that the thickness of the colorless transparent polyimide layer becomes from several hundred nm to several tens of micrometers.

The thickness of the polyimide film thus formed is not particularly limited and can be appropriately adjusted according to the application to which it is applied. For example, in the range of 10 to 150 mu m, and preferably in the range of 10 to 80 mu m.

In the present invention, the transparent polyimide film prepared as described above can be used in various fields, and particularly, a display for an organic EL device (OLED), a display for a liquid crystal device, a TFT substrate, a flexible printed circuit board , A flexible OLED surface light-emitting substrate, and a flexible substrate for a flexible display substrate such as a substrate material for electron bombardment.

Hereinafter, the present invention will be described more specifically by way of specific examples. The following examples are provided to aid understanding of the present invention, and the scope of the present invention is not limited thereto.

[Synthesis of acid dianhydride monomer of formula (1)

[Synthesis Example 1] Synthesis of Compound 1

1-1. Synthesis of intermediate 2

(25.3 g, 100 mmol), 2- (3,4-dimethyl-2- (trifluoromethyl) phenyl) -4,4,5,5-tetramethyl- 1,3,2-dioxaborolane was added to (33g, 110mmol), Pd ( PPh 3) 4 (6.7g, 5 mol%) to the flask. 200 ml of toluene and 100 ml of THF were added, and an aqueous solution in which K ₂ CO ₃ (41.5 g, 300 mmol) was dissolved in distilled water (100 ml) was added, followed by heating and stirring for 12 hours.

After confirming that the reaction was completed by TLC, the reaction solution was filtered and extracted twice with 100 ml of ethyl acetate. The solvent was removed using a rotary evaporator and crystallization was performed using MeOH to obtain compound b (32.88 g, yield 95%).

Elemental Analysis: C, 62.43; H, 4.66; F, 32.92

HRMS [M] &lt; ⁺ & gt ^; : 346

1-2. Synthesis of intermediate 3

3,4,4 ', 5'-tetramethyl-2,2'-bis (trifluoromethyl) biphenyl (32.88 g, 95 mmol) was placed in a flask. 200 ml of Tert-Butanol and 200 ml of H ₂ O were added and the mixture was heated and stirred at 70 ° C. KMnO ₄ (150.1 g, 950 mmol) was added little by little and the mixture was heated and stirred at 78 ° C for 3 hours.

After confirming that the reaction was completed by TLC, the reaction solution was filtered, and 300 ml of a 1 molar solution of Na ₂ S ₂ O ₃ was added little by little. The reaction solution was filtered at room temperature to remove the inorganic substances, and the volume of Tert-Butanol and H ₂ O was reduced to 1/5 by a rotary evaporator. The acidity was adjusted to pH 1 by adding HCl a little, resulting in a white suspension, which was filtered, washed and dried at 5 ° C to give intermediate 3 (26.56 g, 62% yield).

Elemental Analysis: C, 46.37; H, 1.73; F, 24.45; O, 27.45

HRMS [M] &lt; ⁺ & gt ^; : 466

1-3. Synthesis of Compound 1

26.56 g (58.9 mmol) of Intermediate 3, 36.05 g (354 mmol) of anhydrous acetic acid and 150 g of toluene were heated and stirred at 130 占 폚. After cooling to room temperature for 30 minutes, the white crystals precipitated by cooling on ice were washed with toluene and dried under reduced pressure to obtain 22.8 g (yield 90%) of white crystals.

Elemental Analysis: C, 50.25; H, 0.94; F, 26.50; O, 22.31

HRMS [M] &lt; ⁺ & gt ^; : 430

[Synthesis Example 2] Synthesis of Compound 2

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 50.25; H, 0.94; F, 26.50; O, 22.31

HRMS [M] &lt; ⁺ & gt ^; : 430

[Synthesis Example 3] Synthesis of Compound 3

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 50.25; H, 0.94; F, 26.50; O, 22.31

HRMS [M] &lt; ⁺ & gt ^; : 430

[Synthesis Example 4] Synthesis of Compound 4

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 63.03; H, 2.07; F, 13.00; O, 21.90

HRMS [M] &lt; ⁺ & gt ^; : 438

[Synthesis Example 5] Synthesis of Compound 5

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 56.93; H, 1.59; F, 22.51; O, 18.96

HRMS [M] &lt; ⁺ & gt ^; : 506

[Synthesis Example 6] Synthesis of Compound 6

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 56.93; H, 1.59; F, 22.51; O, 18.96

HRMS [M] &lt; ⁺ & gt ^; : 506

[Synthesis Example 7] Synthesis of Compound 7

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 56.93; H, 1.59; F, 22.51; O, 18.96

HRMS [M] &lt; ⁺ & gt ^; : 506

[Synthesis Example 8] Synthesis of Compound 8

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 52.28; H, 1.23; F, 29.77; O, 16.72

HRMS [M] &lt; ⁺ &gt;: 574

[Synthesis Example 9] Synthesis of Compound 9

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 52.28; H, 1.23; F, 29.77; O, 16.72

HRMS [M] &lt; ⁺ &gt;: 574

[Synthesis Example 10] Synthesis of Compound 10

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 56.93; H, 1.59; F, 22.51; O, 18.96

HRMS [M] &lt; ⁺ & gt ^; : 506

[Synthesis Example 11] Synthesis of Compound 11

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 56.93; H, 1.59; F, 22.51; O, 18.96

HRMS [M] &lt; ⁺ & gt ^; : 506

[Synthesis Example 12] Synthesis of Compound 12

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 52.28; H, 1.23; F, 29.77; O, 16.72

HRMS [M] &lt; ⁺ &gt;: 574

[Synthesis Example 13] Synthesis of Compound 13

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 52.28; H, 1.23; F, 29.77; O, 16.72

HRMS [M] &lt; ⁺ &gt;: 574

[Synthesis Example 14] Synthesis of Compound 14

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 52.28; H, 1.23; F, 29.77; O, 16.72

HRMS [M] &lt; ⁺ &gt;: 574

[Synthesis Example 15] Synthesis of Compound 15

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 52.28; H, 1.23; F, 29.77; O, 16.72

HRMS [M] &lt; ⁺ &gt;: 574

[Synthesis Example 16] Synthesis of Compound 16

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 61.87; H, 2.08; F, 19.57; O, 16.48

HRMS [M] &lt; ⁺ & gt ^; : 582

[Synthesis Example 17] Synthesis of Compound 17

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 53.50; H, 1.40; F, 31.73; O, 13.36

HRMS [M] &lt; ⁺ & gt ^; : 718

[Synthesis Example 18] Synthesis of Compound 18

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 47.80; H, 0.94; F, 40.02; O, 11.24

HRMS [M] &lt; ⁺ & gt ^; : 854

[Synthesis Example 19] Synthesis of Compound 19

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 53.50; H, 1.40; F, 31.73; O, 13.36

HRMS [M] &lt; ⁺ & gt ^; : 718

[Synthesis Example 20] Synthesis of Compound 20

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 53.50; H, 1.40; F, 31.73; O, 13.36

HRMS [M] &lt; ⁺ & gt ^; : 718

[Synthesis Example 21] Synthesis of Compound 21

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 61.87; H, 2.08; F, 19.57; O, 16.48

HRMS [M] &lt; ⁺ & gt ^; : 582

[Synthesis Example 22] Synthesis of Compound 22

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 53.50; H, 1.40; F, 31.73; O, 13.36

HRMS [M] &lt; ⁺ & gt ^; : 718

[Synthesis Example 23] Synthesis of Compound 23

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 61.87; H, 2.08; F, 19.57; O, 16.48

HRMS [M] &lt; ⁺ & gt ^; : 582

[Synthesis Example 24] Synthesis of Compound 24

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 54.31; H, 1.52; F, 33.04; O, 11.13

HRMS [M] &lt; ⁺ & gt ^; : 862

[Synthesis Example 25] Synthesis of Compound 25

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 54.31; H, 1.52; F, 33.04; O, 11.13

HRMS [M] &lt; ⁺ & gt ^; : 862

[Synthesis Example 26] Synthesis of Compound 26

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 49.85; H, 0.70; F, 32.85; O, 16.60

HRMS [M] &lt; ⁺ &gt;: 578

[Synthesis Example 27] Synthesis of Compound 27

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 49.61; H, 0.56; F, 36.62; O, 13.22

HRMS [M] &lt; ⁺ & gt ^; : 726

[Synthesis Example 28] Synthesis of Compound 28

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 55.06; H, 1.23; F, 29.03; O, 14.67

HRMS [M] &lt; ⁺ & gt ^; : 654

[Synthesis Example 29] Synthesis of Compound 29

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 49.85; H, 0.70; F, 32.85; O, 16.60

HRMS [M] &lt; ⁺ &gt;: 578

[Synthesis Example 30] Synthesis of Compound 30

Synthesis was carried out using the same method as the synthesis of Compound 1 of Example 1. Elemental Analysis: C, 49.45; H, 0.46; F, 39.11; O, 10.98

HRMS [M] &lt; ⁺ & gt ^; : 874

[Synthesis of transparent polyamic acid composition and production of polyimide film]

[Example 1]

1. Preparation of transparent polyamic acid composition

216.038 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged into a 500-ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-TFDB) was added, and the mixture was stirred for 1 hour to completely dissolve it. Thereafter, 2,2-bis (3,4-dicarboxyphenyl) hexa fluoropropane dianhydride (6-FDA) and compound 1 were sequentially added to the solution in an amount of 19.975 g and 2.149 g, and the mixture was cooled to 30 DEG C and dissolved. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After completion of the reaction of the monomer, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 20000 CPs at 25 캜.

2. Preparation of transparent polyimide film

The transparent polyamic acid solution was spin-coated on LCD glass and dried in a convection oven at 80 ° C for 30 minutes, at 150 ° C for 30 minutes, at 200 ° C for 1 hour, and at 300 ° C for 1 hour, And the imidization reaction proceeded. Thus, a transparent polyimide film having a film thickness of 30 탆 with an imidization ratio of 85% or more was prepared. Thereafter, the glass was etched with hydrofluoric acid to obtain a polyimide film.

[Example 2]

1. Preparation of transparent polyamic acid composition

216.267 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged into a 500 ml three-necked round bottom flask, and the temperature of the reactor was raised to 50 ° C to obtain 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-TFDB) was added, and the mixture was stirred for 1 hour to completely dissolve it. Then, 2,2-bis (3,4-dicarboxyphenyl) hexa fluoropropane dianhydride (6-FDA) and compound 4 were sequentially added to the solution in the order of 19.975 g, 2.190 g, and then cooled to 30 DEG C and dissolved. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 21000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 3]

1. Preparation of transparent polyamic acid composition

219.95 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged into a 500-ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-TFDB) was added, and the mixture was stirred for 1 hour to completely dissolve it. Then, 2,2-bis (3,4-dicarboxyphenyl) hexa fluoropropane dianhydride (6-FDA) and compound 7 were sequentially added to 17.775 g and 5.059 g, and the mixture was cooled to 30 DEG C and dissolved. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 19000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 4]

1. Preparation of transparent polyamic acid composition

223801 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged into a 500-ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-TFDB) was added, and the mixture was stirred for 1 hour to completely dissolve it. Then, 2,2-bis (3,4-dicarboxyphenyl) hexa fluoropropane dianhydride (6-FDA) and compound 15 were sequentially added to 17,755 g and 5.739 g, and the mixture was cooled to 30 DEG C and dissolved. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 23000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 5]

1. Preparation of transparent polyamic acid composition

231.96 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged into a 500 ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-TFDB) was added, and the mixture was stirred for 1 hour to completely dissolve it. Then, 2,2-bis (3,4-dicarboxyphenyl) hexa fluoropropane dianhydride (6-FDA) and compound 17 were sequentially added to 17,755 g and 7.179 g, and the mixture was cooled to 30 DEG C and dissolved. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 20000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 6]

1. Preparation of transparent polyamic acid composition

221.203 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged into a 500-ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-TFDB) was added, and the mixture was stirred for 1 hour to completely dissolve it. Then, 2,2-bis (3,4-dicarboxyphenyl) hexa fluoropropane dianhydride (6-FDA) and compound 23 were sequentially added to 17,755 g, 5.280 g, and then cooled to 30 DEG C to dissolve. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 19000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 7]

1. Preparation of transparent polyamic acid composition

232.409 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged into a 500 ml three-necked round bottom flask, and the temperature of the reactor was raised to 50 ° C to obtain 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-TFDB) was added, and the mixture was stirred for 1 hour to completely dissolve it. Then, 2,2-bis (3,4-dicarboxyphenyl) hexa fluoropropane dianhydride (6-FDA) and compound 27 were sequentially added to 17,755 g, 7.258 g, and then cooled to 30 DEG C to dissolve. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 20000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 8]

1. Preparation of transparent polyamic acid composition

216.274 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged in a 500 ml three-necked round bottom flask, and the temperature of the reactor was raised to 50 ° C to obtain 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-TFDB) was added, and the mixture was stirred for 1.5 hours to dissolve completely. Then, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-biphenyltetracarboxylic dianhydride And compound 4 were sequentially added in amounts of 13.965 g and 5.201 g, respectively, and then cooled to 30 ° C and dissolved. At this time, the solid content was 15%, and then stirred for 7 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 25000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 9]

1. Preparation of transparent polyamic acid composition

210.359 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged into a 500 ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-TFDB) was added thereto, and the mixture was stirred for 1.5 hours to completely dissolve it. Then, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-biphenyltetracarboxylic dianhydride And compound 7 were sequentially added to 9.371 g and 10.751 g, respectively, and then cooled to 30 ° C and dissolved. At this time, the solid content was 15%, and then stirred for 7 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 28000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 10]

1. Preparation of transparent polyamic acid composition

N, N-dimethylacetamide (DMAc) (209.995 g, 85.0 wt%) was charged into a 500-ml three-necked round bottom flask, and the temperature of the reactor was raised to 50 ° C to obtain 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-TFDB) was added thereto, and the mixture was stirred for 1.5 hours to completely dissolve it. Then, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-biphenyltetracarboxylic dianhydride And compound 19 were sequentially added to 10.290 g and 10.768 g, respectively, and then cooled to 30 ° C and dissolved. At this time, the solid content was 15%, and then stirred for 6 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 22000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 11]

1. Preparation of transparent polyamic acid composition

210.583 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged into a 500-ml three-necked round bottom flask and the temperature of the reactor was raised to 50 캜 to obtain 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-TFDB) was added, and the mixture was stirred for 1.5 hours to be completely dissolved. Then, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-biphenyltetracarboxylic dianhydride And compound 21 were added sequentially in an amount of 15.279 g and 3.364 g, respectively, and then cooled to 30 ° C and dissolved. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 21000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 12]

1. Preparation of transparent polyamic acid composition

212.938 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged into a 500-ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-TFDB) was added, and the mixture was stirred for 1.5 hours to be completely dissolved. Then, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-biphenyltetracarboxylic dianhydride And compound 28 were sequentially added in an amount of 15.297 g and 3.780 g, respectively, and then cooled to 30 ° C and dissolved. At this time, the solid content was 15%, and then stirred for 7 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 24000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 13]

1. Preparation of transparent polyamic acid composition

210.837 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged into a 500-ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-TFDB) was added thereto, and the mixture was stirred for 1.5 hours to completely dissolve it. Then, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-biphenyltetracarboxylic dianhydride And compound 27 were sequentially added in the order of 12.495 g and 7.711 g, respectively, and then cooled to 30 ° C and dissolved. At this time, the solid content was 15%, and then stirred for 7 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 26000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 14]

1. Preparation of transparent polyamic acid composition

N, N-dimethylacetamide (DMAc) (211.050 g, 85.0 wt%) was charged in a 500 ml three-neck round bottom flask, and the temperature of the reactor was raised to 50 ° C to obtain 2,2'- ) 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether, 6-FODA) was added to the solution, and the mixture was stirred for 1 hour to completely dissolve it. Then, 11.811 g and 2.933 g of 1,2,3,4-cyclobutane tetracarboxylic acid dianhydride (1, 2, 3, 4-Cyclobutane Tetracarboxylic Dianhydride, CBDA) and compound 4 were sequentially added, Lt; / RTI &gt; At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 18000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 15]

1. Preparation of transparent polyamic acid composition

N, N-dimethylacetamide (DMAc) (209.026 g, 85.0 wt%) was charged in a 500 ml three-neck round bottom flask, and the temperature of the reactor was raised to 50 ° C to obtain 2,2'- ) -4,4'-diaminodiphenyl ether (6-FODA) were added to the solution, and the mixture was stirred for 1 hour to completely dissolve it. Then, 8.370 g and 8.017 g of 1,2,3,4-cyclobutane tetracarboxylic acid dianhydride (1, 2, 3, 4-Cyclobutane Tetracarboxylic Dianhydride, CBDA) and compound 4 were sequentially added, Lt; / RTI &gt; At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 19000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 16]

1. Preparation of transparent polyamic acid composition

210.804 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged into a 500 ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'- ) -4,4'-diaminodiphenyl ether (6-FODA) was added to the solution, and the mixture was stirred for 1 hour to completely dissolve it. Then, 8.166 g and 9.035 g of 1,2,3,4-cyclobutane tetracarboxylic acid dianhydride (1,2,3,4-Cyclobutane Tetracarboxylic Dianhydride, CBDA) and compound 7 were sequentially added, Lt; / RTI &gt; At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 21000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 17]

1. Preparation of transparent polyamic acid composition

N, N-dimethylacetamide (DMAc) (211.706 g, 85.0 wt%) was charged in a 500 ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'- ) -4,4'-diaminodiphenyl ether (2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether, 6-FODA) were added and stirred for 1 hour to dissolve completely. Then, 11.024 g and 5.336 g of 1,2,3,4-cyclobutane tetracarboxylic dianhydride (1, 2, 3, 4-Cyclobutane Tetracarboxylic Dianhydride, CBDA) and compound 18 were sequentially added, Lt; / RTI &gt; At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 22000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 18]

1. Preparation of transparent polyamic acid composition

N, N-dimethylacetamide (DMAc) (209.102 g, 85.0 wt%) was charged in a 500-ml three-necked round bottom flask and the temperature of the reactor was raised to 50 캜 to obtain 2,2'- ) -4,4'-diaminodiphenyl ether (6-FODA) was added to the mixture, and the mixture was stirred for 1 hour to completely dissolve the mixture. Then, 6.941 g and 12.960 g of 1,2,3,4-cyclobutane tetracarboxylic dianhydride (1, 2, 3, 4-Cyclobutane Tetracarboxylic Dianhydride, CBDA) and compound 18 were sequentially added, Lt; / RTI &gt; At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 21000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 19]

1. Preparation of transparent polyamic acid composition

N, N-dimethylacetamide (DMAc) (209.026 g, 85.0 wt%) was charged in a 500 ml three-neck round bottom flask, and the temperature of the reactor was raised to 50 ° C to obtain 2,2'- ) -4,4'-diaminodiphenyl ether (6-FODA) was added to the solution, and the mixture was stirred for 1 hour to completely dissolve it. Then, 7.349 g and 11.538 g of 1,2,3,4-cyclobutane tetracarboxylic acid dianhydride (1,2,3,4-Cyclobutane Tetracarboxylic Dianhydride, CBDA) and compound 22 were sequentially added, Lt; / RTI &gt; At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 20000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 20]

1. Preparation of transparent polyamic acid composition

207.177 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged into a 500 ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'- ) -4,4'-diaminodiphenyl ether (6-FODA) was added to the solution, and the mixture was stirred for 1 hour to completely dissolve it. Then, 7.757 g and 9.803 g of 1,2,3,4-cyclobutane tetracarboxylic dianhydride (1,2,3,4-Cyclobutane Tetracarboxylic Dianhydride, CBDA) and compound 26 were sequentially added, and then cooled to 30 ° C Lt; / RTI &gt; At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 20000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 21]

1. Preparation of transparent polyamic acid composition

208.690 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged in a 500 ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'- ) -4,4'-diaminodiphenyl ether (6-FODA) was added to the solution, and the mixture was stirred for 1 hour to completely dissolve it. Then, 7.962 g and 9.366 g of 1,2,3,4-cyclobutane tetracarboxylic dianhydride (1,2,3,4-Cyclobutane Tetracarboxylic Dianhydride, CBDA) and compound 29 were sequentially added, Lt; / RTI &gt; At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 23000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 22]

1. Preparation of transparent polyamic acid composition

212.298 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged in a 500 ml three-neck round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'- ) Sulfone (4-aminophenyl) sulfone, 4,4'-DDS) was added to the solution, and the solution was completely dissolved by stirring for 1.5 hours. Then, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-biphenyltetracarboxylic dianhydride And compound 4 were sequentially added to 11.020 g and 10.945 g, respectively, and then cooled to 30 ° C and dissolved. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 22000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 23]

1. Preparation of transparent polyamic acid composition

207.603 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged in a 500 ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'- ) 4,5'-bis (4-aminophenyl) sulfone, 4,4'-DDS) was added and stirred for 1.5 hours to dissolve completely. Then, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-biphenyltetracarboxylic dianhydride And compound 7 were sequentially added to 10.309 g and 11.827 g, respectively, and the mixture was cooled to 30 ° C and dissolved. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 25000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 24]

1. Preparation of transparent polyamic acid composition

N, N-dimethylacetamide (DMAc) (211.296 g, 85.0 wt%) was charged in a 500 ml three-necked round bottom flask and the temperature of the reactor was raised to 50 캜 to obtain 2,2'- ) Sulfone (2,2'-bis (4-aminophenyl) sulfone, 4,4'-DDS) was added and stirred for 1.5 hours to dissolve completely. Then, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-biphenyltetracarboxylic dianhydride And compound 7 were sequentially added to 3.081 g and 21.207 g, respectively, and then cooled to 30 ° C and dissolved. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 26000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 25]

1. Preparation of transparent polyamic acid composition

207.051 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged in a 500 ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'- ) Sulfone (4-aminophenyl) sulfone, 4,4'-DDS) was added to the solution, and the solution was completely dissolved by stirring for 1.5 hours. Then, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-biphenyltetracarboxylic dianhydride And compound 11 were sequentially added to 12.442 g and 9.176 g, respectively, and then cooled to 30 ° C and dissolved. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 24000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 26]

1. Preparation of transparent polyamic acid composition

212.298 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged in a 500 ml three-neck round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'- ) Sulfone (4-aminophenyl) sulfone, 4,4'-DDS) was added to the solution, and the solution was completely dissolved by stirring for 1.5 hours. Then, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-biphenyltetracarboxylic dianhydride And compound 16 were sequentially added to 14.693 g and 7.271 g, respectively, and then cooled to 30 ° C and dissolved. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 25000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 27]

1. Preparation of transparent polyamic acid composition

206.915 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged in a 500 ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'- ) Sulfone (4-aminophenyl) sulfone, 4,4'-DDS) was added to the solution, and the solution was completely dissolved by stirring for 1.5 hours. Then, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-biphenyltetracarboxylic dianhydride And compound 19 were sequentially added in an amount of 16.530 g and 4.485 g, respectively, and then cooled to 30 ° C and dissolved. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 24000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Example 27]

1. Preparation of transparent polyamic acid composition

208.624 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged into a 500 ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'- ) Sulfone (4-aminophenyl) sulfone, 4,4'-DDS) was added to the solution and stirred for 1.5 hours to dissolve completely. Then, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-biphenyltetracarboxylic dianhydride And compound 21 were sequentially added in amounts of 17.063 g and 3.753 g, respectively, and then cooled to 30 DEG C and dissolved. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 23000 CPs at 25 캜

2. Preparation of transparent polyimide film

The process for producing a colorless transparent polyimide film was carried out in the same manner as in Example 1 above.

[Comparative Example 1]

1. Preparation of transparent polyamic acid composition

209.671 g (85.0% by weight) of N, N-dimethylacetamide (DMAc) was charged in a 500 ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-TFDB) was added, and the mixture was stirred for 1.5 hours to dissolve completely. Thereafter, 21.501 g of 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 6-FDA was added thereto, To dissolve it. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 18000 CPs at 25 캜

2. Preparation of transparent polyimide film

The polyamic acid solution was spin-coated on a glass for LCD and dried in a convection oven at 80 DEG C for 30 minutes, 150 DEG C for 30 minutes, 200 DEG C for 1 hour, and 300 DEG C for 1 hour, Imidazation reaction proceeded. Thus, a transparent polyimide film having a film thickness of 10 탆 with an imidization ratio of 85% or more was produced. Thereafter, the glass was etched with hydrofluoric acid to obtain a polyimide film.

[Comparative Example 2]

1. Preparation of transparent polyamic acid composition

206.585 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged into a 500 ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-TFDB) was added, and the mixture was stirred for 1.5 hours to dissolve completely. Then, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) , 3', 4,4'-biphenyltetracarboxylic dianhydride After the addition of 17.456 g, the mixture was cooled to 30 캜 and dissolved. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 21000 CPs at 25 캜

2. Preparation of transparent polyimide film

The polyamic acid solution was spin-coated on a glass for LCD and dried in a convection oven at 80 DEG C for 30 minutes, 150 DEG C for 30 minutes, 200 DEG C for 1 hour, and 300 DEG C for 1 hour, Imidazation reaction proceeded. Thus, a transparent polyimide film having a film thickness of 10 탆 with an imidization ratio of 85% or more was produced. Thereafter, the glass was etched with hydrofluoric acid to obtain a polyimide film.

[Comparative Example 3]

1. Preparation of transparent polyamic acid composition

206.352 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged into a 500 ml three-necked round bottom flask, the temperature of the reactor was raised to 50 캜, 23 g of 2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether (2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether, 6-FODA) Lt; / RTI &gt; and completely dissolved by stirring. Then, 13.415 g of 31,2,3,4-cyclobutane tetracarboxylic dianhydride (1,2,3,4-Cyclobutane Tetracarboxylic Dianhydride, CBDA) was added, and the mixture was cooled to 30 DEG C and dissolved. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 18000 CPs at 25 캜

2. Preparation of transparent polyimide film

The polyamic acid solution was spin-coated on a glass for LCD and dried in a convection oven at 80 DEG C for 30 minutes, 150 DEG C for 30 minutes, 200 DEG C for 1 hour, and 300 DEG C for 1 hour, Imidazation reaction proceeded. Thus, a transparent polyimide film having a film thickness of 10 탆 with an imidization ratio of 85% or more was produced. Thereafter, the glass was etched with hydrofluoric acid to obtain a polyimide film.

[Comparative Example 4]

1. Preparation of transparent polyamic acid composition

210.482 g (85.0 wt%) of N, N-dimethylacetamide (DMAc) was charged in a 500 ml three-necked round bottom flask and the temperature of the reactor was raised to 50 ° C to obtain 2,2'- ) Sulfone (2,2'-bis (4-aminophenyl) sulfone, 4,4'-DDS) was added and stirred for 1.5 hours to dissolve completely. Then, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) , 3', 4,4'-biphenyltetracarboxylic dianhydride And the mixture was cooled to 30 DEG C and dissolved. At that time, the solid content was 15%, and the mixture was stirred for 5 hours. After the reaction of the monomer was completed, the solution was naturally cooled to obtain a transparent polyamic acid composition having a solution viscosity of 24000 CPs at 25 캜

2. Preparation of transparent polyimide film

The polyamic acid solution was spin-coated on a glass for LCD and dried in a convection oven at 80 DEG C for 30 minutes, 150 DEG C for 30 minutes, 200 DEG C for 1 hour, and 300 DEG C for 1 hour, Imidazation reaction proceeded. Thus, a transparent polyimide film having a film thickness of 10 탆 with an imidization ratio of 85% or more was produced. Thereafter, the glass was etched with hydrofluoric acid to obtain a polyimide film.

The compositions of the polyamic acid compositions prepared in Examples 1 to 28 and Comparative Examples 1 to 4 are shown in Table 1 below. Here, the weight% represents the weight ratio of each monomer in the acid anhydride to the total solid weight, and the mol% represents the molar ratio of the respective monomers in the total acid dianhydride.

Diamine Acid anhydride The first monomer The second monomer ingredient wt% Mol% ingredient wt% Mol% Example 1 TFDB 6FDA 52.39 90 Compound 1 5.64 10 Example 2 TFDB 6FDA 52.34 90 Compound 4 5.74 10 Example 3 TFDB 6FDA 45.77 80 Compound 7 13.03 20 Example 4 TFDB 6FDA 44.96 80 Compound 15 14.53 20 Example 5 TFDB 6FDA 43.37 80 Compound 17 17.54 20 Example 6 TFDB 6FDA 45.48 80 Compound 23 13.53 20 Example 7 TFDB 6FDA 43.29 80 Compound 27 17.70 20 Example 8 TFDB BPDA 36.59 80 Compound 4 13.63 20 Example 9 TFDB BPDA 25.24 60 Compound 7 28.96 40 Example 10 TFDB BPDA 27.77 70 Compound 19 29.06 30 Example 11 TFDB BPDA 41.14 90 Compound 21 9.06 10 Example 12 TFDB BPDA 40.71 90 Compound 28 10.06 10 Example 13 TFDB BPDA 33.58 80 Compound 27 20.73 20 Example 14 6FODA CBDA 31.71 90 Compound 4 7.88 10 Example 15 6FODA CBDA 22.69 70 Compound 4 21.73 30 Example 16 6FODA CBDA 21.95 70 Compound 7 24.29 30 Example 17 6FODA CBDA 29.51 90 Compound 18 14.28 10 Example 18 6FODA CBDA 18.81 70 Compound 18 35.12 30 Example 19 6FODA CBDA 19.92 70 Compound 22 31.28 30 Example 20 6FODA CBDA 21.22 70 Compound 26 26.81 30 Example 21 6FODA CBDA 21.62 70 Compound 29 25.43 30 Example 22 4,4-DDS BPDA 29.41 60 Compound 4 29.21 40 Example 23 4,4-DDS BPDA 28.14 60 Compound 7 32.28 40 Example 24 4,4-DDS BPDA 8.26 20 Compound 7 56.87 80 Example 25 4,4-DDS BPDA 33.98 70 Compound 11 25.06 30 Example 26 4,4-DDS BPDA 39.22 80 Compound 16 19.41 20 Example 27 4,4-DDS BPDA 45.27 90 Compound 19 12.28 10 Example 28 4,4-DDS BPDA 46.35 90 Compound 21 10.19 10 Comparative Example 1 TFDB 6FDA 58.11 100 - - - Comparative Example 2 TFDB BPDA 47.88 100 - - - Comparative Example 3 6FODA CBDA 36.84 100 - - - Comparative Example 4 4,4-DDS BPDA 54.23 100 - - -

[Property evaluation]

The properties of the transparent polyimide films prepared in Examples 1 to 28 and Comparative Examples 1 to 4 were evaluated by the following methods, and the results are shown in Table 2 below.

&Lt; Property evaluation method &

(1) Measurement of light transmittance (Trans.)

Was measured at a wavelength of 550 nm using a UV-Vis NIR Spectrophotometer at a C light source of ASTM E313-73 and a viewing angle of 2 degrees.

(2) Yellowness measurement (Y.I)

The yellowness at 550 nm was measured according to the ASTM E313 standard using a UV spectrometer (Kotikaminolta CM-3700d).

(3) Glass Transition Temperature (T _g )

The glass transition temperature was measured using a differential scanning calorimeter (DSC, TA Instrument, Q200).

(4) Thickness measurement

The thickness of the film was measured using a non-contact refractive index measuring device (Elli-RP, Ellipso technology) at a wavelength of 550 nm, after coating a transparent polyamic acid resin with a thickness of 20 μm or less on a silicon wafer Respectively.

(5) Tensile strength (St) and modulus (Modu.)

The tensile strength MPa and the modulus of elasticity GPa were measured at a tensile speed of 10 mm / min according to ISO 527-3 standard

thickness
(탆) Permeability
(%) Yellowness
(Y.I) Glass transition temperature
(Tg, ° C) The tensile strength
(Mpa) Modulus of elasticity
(Gpa) Example 1 51 90 2.5 349 143 4.8 Example 2 52 91 2.4 345 141 4.5 Example 3 51 92 2.5 347 147 4.4 Example 4 53 91 2.4 339 141 4.2 Example 5 55 90 2.6 338 145 4.3 Example 6 48 91 3.0 345 135 4.1 Example 7 47 91 2.4 342 141 4.5 Example 8 51 90 2.2 351 140 4.4 Example 9 48 91 2.3 350 142 4.8 Example 10 50 92 2.5 355 139 4.3 Example 11 51 91 2.1 362 138 4.3 Example 12 51 90 2.5 368 139 4.4 Example 13 53 91 2.7 352 140 4.2 Example 14 56 91 2.6 343 126 3.5 Example 15 47 92 2.2 338 131 4.1 Example 16 49 91 2.2 331 131 4.0 Example 17 50 92 2.1 340 135 4.2 Example 18 49 90 2.5 336 130 3.9 Example 19 50 92 2.4 336 134 4.4 Example 20 51 90 2.6 338 133 4.1 Example 21 55 91 2.5 335 137 4.2 Example 22 53 90 2.9 335 127 4.1 Example 23 54 91 3.1 341 131 4.0 Example 24 49 90 3.0 345 131 4.2 Example 25 45 90 3.1 347 128 3.8 Example 26 50 90 3.2 348 129 3.9 Example 27 49 90 3.0 343 131 3.9 Example 28 50 90 2.9 343 129 4.0 Comparative Example 1 51 89 3.5 334 124 3.9 Comparative Example 2 50 90 4.6 350 139 4.3 Comparative Example 3 51 91 3.4 321 118 3.2 Comparative Example 4 55 89 5.5 334 124 3.7

As shown in Table 2, in Examples 1 to 7 in which the novel acid dianhydride monomer of Formula 1 was added according to the present invention, the yellowness degree was lowered and the glass transition temperature was increased compared to Comparative Example 1 , Tensile strength and elastic modulus were increased.

In addition, in Examples 8 to 13 in which the novel acid dianhydride monomer of Formula 1 was added according to the present invention, it was confirmed that the yellowness degree of Comparative Example 2 was lowered. The absence of significant differences in glass transition temperature or mechanical properties appears to be due to chemical structural similarities between BPDA and the novel acid anhydride monomers of the present invention.

Also, it was confirmed that Examples 14 to 21, in which the novel acid dianhydride monomer of Formula 1 was added, were significantly improved in terms of glass transition temperature, tensile strength, and elastic modulus as compared with Comparative Example 3. This is because the novel monomers of the above formula (1) are complementary to the glass transition temperature and mechanical properties, which are structural shortcomings of the alicyclic acid anhydride.

In Examples 22 to 28 in which the novel acid dianhydride monomer of Formula 1 was added, the yellowness degree was significantly lowered and the glass transition temperature, tensile strength and elastic modulus were increased.

Taking all the above results into consideration, it has been found that the light transmittance is not lowered by the use of the novel monomer in the present invention. Also, in order to be applied to a flexible display material and a substrate, the transmittance at 550 nm should be 90% or more, and the result of yellowness should be 3 or less.

In addition, since the glass transition temperature of the substrate is in the range of 300 ° C to 400 ° C and satisfies the mechanical characteristics, it can be applied to a flexible display material.

Claims (13)

A compound represented by the following formula (1):
[Chemical Formula 1]

In Formula 1,
A is a single bond or a C ₆ to C ₄₀ arylene group,
X ₁ and X ₂ are the same or different and are each independently selected from the group consisting of hydrogen, halogen, C ₁ -C ₆ alkyl, and C ₁ -C ₆ alkyl substituted with at least one hydrogen,
Provided that when A is a single bond, at least one of X ₁ and X ₂ is a C ₁ -C ₆ alkyl group substituted by a halogen or a halogen atom,
The C ₆ -C ₄₀ arylene group may be substituted with a halogen or a C ₁ -C ₆ alkyl group substituted with a halogen atom, and m is an integer of 0 to 3. The method according to claim 1,
Wherein X ₁ and X ₂ are each independently F or CF ₃ . The method according to claim 1,
Wherein A is selected from the group of substituents represented by the following formula:

,

,

,

,

,

,

In such substituents,
R ₁ to R ₃ are the same as or different from each other, and each independently selected from the group consisting of hydrogen, F, and CF ₃ . The method according to claim 1,
Wherein the compound represented by Formula 1 is selected from the group of compounds represented by the following formulas.

(a) a diamine;
(b) an acid dianhydride containing the compound of formula (1) as defined in any one of claims 1 to 4; And
(c) an organic solvent,
Wherein the compound represented by Formula 1 is contained in an amount of 10 to 80 mol% based on 100 mol% of the total acid dianhydride. 6. The method of claim 5,
Wherein the acid dianhydride further comprises at least one selected from the group consisting of a fluorinated aromatic first acid dianhydride, an alicyclic second acid dianhydride, and a non-fluorinated aromatic dianhydride. The method according to claim 6,
Wherein the content of the at least one compound selected from the group consisting of the first acid dianhydride, the second acid dianhydride and the third acid dianhydride is 20 to 90 mol% based on 100 mol% of the total acid dianhydride. . 6. The method of claim 5,
The diamine may be a fluorinated primary diamine; A sulfone-based second diamine, an alicyclic tertiary amine, and an ether-based quaternary amine, based on the total weight of the polyamic acid composition. 9. The method of claim 8,
Wherein the content of the fluorinated first diamine, the sulfone second diamine, the alicyclic third amine and the ether fourth amine is 10 to 100 mol% based on 100 mol% of the total diamine, respectively. 6. The method of claim 5,
Wherein the ratio (a / b) of the number of moles of the diamine (a) to the number of moles of the acid anhydride (b) is in the range of 0.7 to 1.3. A transparent polyimide film prepared by imidizing the polyamic acid composition of claim 5. 12. The method of claim 11,
A transparent polyimide film characterized by satisfying the following physical property conditions (i) to (v):
(i) a glass transition temperature (T _g ) in the range of 300 to 400 ° C,
(ii) a light transmittance of 90% or more at a wavelength of 500 nm at a film thickness of 10 to 80 탆,
(iii) the yellowness according to the ASTM E313 standard is 3.3 or less,
(iv) a tensile strength of 125 to 150 MPa,
(v) the tensile modulus is in the range of 3.5 to 5.0 GPa. 12. The method of claim 11,
A transparent polyimide film characterized by being used as a substrate for a flexible display or a protective film.