KR101966737B1 - Polyimide precursor composition and polyimide film manufactured by using same - Google Patents

Abstract

The present invention provides a polyimide film which not only exhibits excellent heat resistance by introducing a fluorene structure to a rigid polyimide chain structure but also has improved optical properties at the same time. In addition, the polyimide according to the present invention has excellent transparency, heat resistance, mechanical strength and flexibility, and can be used as a substrate for a device, a cover substrate for a display, an optical film, an IC (integrated circuit) films, flexible multi-layer FPCs, tapes, touch panels, protective films for optical discs, and the like.

Description

TECHNICAL FIELD [0001] The present invention relates to a polyimide precursor composition and a polyimide film using the polyimide precursor composition and a polyimide film using the polyimide precursor composition.

The present invention provides a polyimide precursor composition for producing a polyimide film having improved heat resistance and transparency.

Polyimide (PI) is a polymer having a relatively low crystallinity or mostly noncrystalline structure. It is easy to synthesize and can produce a thin film film. It also has advantages of not requiring a crosslinking agent for curing, transparency, rigid chain structure Is a polymer material having excellent heat resistance, chemical resistance, excellent mechanical properties, electrical properties and dimensional stability. It is widely used in electric and electronic materials such as automobile, aerospace, flexible circuit board, liquid crystal alignment film for LCD, have.

Although polyimide is a high-performance polymer material having high thermal stability, mechanical properties, chemical resistance, and electrical properties, it does not satisfy the basic requirement for use in the display field, which is a colorless transparent property, . For example, the coefficient of thermal expansion of Kapton sold by DuPont has a thermal expansion coefficient as low as about 30 ppm / ° C, but this is still below the requirements of plastic substrates. Therefore, many researches have been carried out to minimize changes in optical characteristics and thermal history while maintaining the basic characteristics of polyimide.

In general, the aromatic polyimide has a deep brown color because the π electrons of benzene present in the imide main chain are transferred to the charge transfer complex (CT-complex ). This is because electrons can be excited because σ electrons, π electrons, and nonbonding non-covalent electron pairs exist in the imide structure.

In the case of a general polyimide, the light absorbs light in a visible light range from a wavelength of 400 nm or less to a wavelength of 500 nm. Therefore, in order to lower the CT-complex, which is a disadvantage of the aromatic polyimide, an element having relatively high electronegativity such as trifluoromethyl (-CF ₃ ), sulfone (-SO ₂ ), and ether (-O-) In addition, by introducing an olefinic cycloolefin structure that is not benzene, there is a method of reducing the resonance effect by restricting the movement of the π electrons. By reducing the density of π electrons present in the main chain, a colorless transparent polyimide film is obtained Can be manufactured.

On the other hand, polyamideimide has been widely used as an industrial material for electric, electronic, mechanical, aviation, and the like since it has excellent heat resistance, mechanical strength and electrical characteristics. In addition, polyamide imide is widely known to be soluble in organic solvents, and it is used for enamel varnish, coating agent for electrical insulation, paint and the like.

However, for use in the display field, it is necessary to develop a polymer for a flexible display having a lower coefficient of thermal expansion, high solubility, transparency and thermal stability.

A problem to be solved by the present invention is to provide a polyimide precursor composition for producing a polyimide film having improved heat resistance and optical properties.

Another object of the present invention is to provide a polyimide film made of the polyimide precursor composition.

Another object of the present invention is to provide a display device using the polyimide precursor composition.

In order to solve the above-described technical problem,

A polyimide precursor prepared by using a diamine having a molecular weight of 4000 g / mol or more and a tetracarboxylic dianhydride having a structure represented by the following formula (1) in a molecular structure as a polymerization component; And

And Log P is a positive organic solvent.

[Chemical Formula 1]

Wherein R ₁ and R ₂ are each independently a single bond, an alkylene group having 1 to 5 carbon atoms or a divalent aromatic group having 6 or more carbon atoms,

R ₃ , R ₄ , R ₅ and R ₆ are each independently an alkyl group of 1 to 5,

R ₇ , R ₈ , R ₉ and R ₁₀ are each independently an alkenyl group having 2 to 10 carbon atoms,

m1 and m2 are each independently an integer of 1 or more.

According to one embodiment, the molecular weight of the diamine having the structure of Formula 1 may be higher than 4400 g / mol.

According to one embodiment, the diamine of Formula 1 may be present in an amount of 1 to 20 mol% based on the total diamine.

According to one embodiment, the weight of the diamine of Formula 1 may be 20 to 50 wt% based on the total weight of the polyimide precursor composition.

According to one embodiment, the tetracarboxylic dianhydride may be selected from tetracarboxylic dianhydrides having a tetravalent organic structure of the following formulas (2a) to (2i).

 (2a)

(2b)

[Chemical Formula 2c]

(2d)

[Formula 2e]

(2f)

[Chemical Formula 2g]

(2i)

In formulas (2a) to (2i), R11 to R24 each independently represent a halogen atom selected from the group consisting of -F, -Cl, -Br and -I, a hydroxyl group (-OH), a thiol group a group (-NO _2), a cyano group, a substituent selected from aryl groups, alkyl groups having 1 to 10 carbon atoms, alkoxy having 1 to 4 carbon atoms, halogenoalkyl, having 1 to 10 carbon atoms halogenoalkyl, having 6 to 20 carbon atoms of,

a3 is an integer of 0 to 8; a4 and a5 are each independently an integer of 0 to 3; and a7 and a8 are each independently an integer of 0 to 3 A15 and a16 are each independently an integer of 0 to 4, a17 and a18 are each independently an integer of 0 to 4, and a10 and a12 are each independently an integer of 0 to 3, a11 is an integer of 0 to 4, a6, a9, a13, a14, a19 and a20 are each independently an integer of 0 to 3,

n is an integer of 1 to 3,

A11 to A16 each independently represent -O-, -CR'R "-, -C (= O) -, -C (= O) O-, -C (= O) NH-, -S-, -, phenylene group, and combinations thereof, wherein R 'and R "are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms .

According to one embodiment, diamine containing the structure of the following formula 3 may be contained in an amount of 80 to 99 mol% in the total diamine content.

(3)

In Formula 3,

R _31, R ₃₂ are each independently -F, -Cl, -Br and -I halogen atom, a hydroxyl group (-OH) is selected from the group consisting of a thiol group (-SH), a nitro group (-NO ₂ ), A cyano group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy group having 1 to 4 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 20 carbon atoms,

Q is a single bond, -O-, -CR'R "-, -C (= O) -, -C (= O) O-, -C (= O) NH-, -S-, -SO 2 - , Phenylene group and combinations thereof, wherein R 'and R "are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms will be.

According to one embodiment, the tetracarboxylic acid dianhydride having the following general formula (4) may be contained in an amount of 20 to 80 mol% in the total tetracarboxylic acid dianhydride.

[Chemical Formula 4]

According to one embodiment, the tetracarboxylic acid dianhydride represented by the following formula (5) may be contained in an amount of 20 to 80 mol% in the total tetracarboxylic dianhydride.

[Chemical Formula 5]

In Formula 5,

Q ₁ and Q ₂ is a single bond, each independently, -O-, -C (= O) -, -C (= O) O-, -C (= O) NH-, -S-, -SO 2 - , Phenylene group, and combinations thereof.

According to one embodiment, tetracarboxylic dianhydrides of the following formulas (4) and (5) may be included.

[Chemical Formula 4]

[Chemical Formula 5]

In Formula 5,

Q ₁ and Q ₂ is a single bond, each independently, -O-, -C (= O) -, -C (= O) O-, -C (= O) NH-, -S-, -SO 2 - , Phenylene group, and combinations thereof.

According to one embodiment, the organic solvent in which Log P is positive is selected from the group consisting of N, N-diethylacetamide, DEAc, N, N-diethylformamide (DEF) , N-ethylpyrrolidone (NEP), and the like.

In order to solve the other problems of the present invention, there is provided a polyimide film produced from the polyimide precursor composition.

According to one embodiment, the haze of the polyimide film may be 2 or less.

According to one embodiment, the Tg of the polyimide film may be 350 DEG C or higher.

According to one embodiment, the CTE of the polyimide film may be 100 ppm / DEG C or less.

The present invention also provides a transparent polyimide substrate for an oxide TFT or an LTPS, which is made of the polyimide precursor composition.

The present invention provides a polyimide precursor composition comprising a polyimide precursor made of a polymerization element containing a diamine having a high molecular weight siloxane structure and an organic solvent having a Log P affinity, and a polyimide film Can exhibit colorless and transparent characteristics and is excellent in heat resistance, mechanical strength and flexibility, and can be used as a substrate for a device, a cover substrate for a display, an optical film, an IC (integrated circuit) package, an adhesive film, flexible printed circuits, tapes, touch panels, protective films for optical discs, and the like.

1 schematically illustrates the principles of the present invention.
Fig. 2 shows the TEM image of a cross-section of a polyimide film prepared by DPS-DMS with a molecular weight of 5700 g / mol and the distribution of Si by STEM HAADF analysis.
FIG. 3 shows a TEM image of a cross section of a polyimide film prepared by DPS-DMS having a molecular weight of 5000 g / mol, a distribution of Si by STEM HAADF analysis, and an EDS analysis result of a cross section.
FIG. 4 shows the results of point analysis by EDS analysis of the bright and dark portions of the TEM image.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In the present specification, all the compounds or organic groups may be substituted or unsubstituted, unless otherwise specified. Herein, the term "substituted" means that at least one hydrogen contained in the compound or organic group is substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, a cycloalkyl group having 3 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, Substituted with a substituent selected from the group consisting of an alkoxy group having 1 to 10 carbon atoms, a carboxylic acid group, an aldehyde group, an epoxy group, a cyano group, a nitro group, an amino group, a sulfonic acid group and derivatives thereof.

In the present specification, the term " combination thereof " means an alkylene group having 1 to 10 carbon atoms (e.g., a methylene group (-CH ₂ -)) , an ethylene group (-CH ₂ CH ₂ -), and the like), having 1 to 10 fluoro-alkylene group (for example, a methylene group fluoroalkyl (-CF ₂ -), ethylene perfluoro (-CF ₂ CF ₂ -), etc.), N, O, P, S, or Si, for the functional groups (e.g., including heteroatoms or this like, a carbonyl group in the molecule (-C = O-), ether group (-O-), ester (Heteroalkylene group including a group (-COO-), -S-, -NH-, or -N = N-), or two or more functional groups are condensed and connected .

Flexible devices accompanied by high temperature processes are required to have high temperature resistance. In particular, OLED (organic light emitting diode) devices using oxide TFT and low temperature polysilicon (LTPS) It is also said.

Even at this temperature, polyimides having excellent heat resistance are liable to be thermally decomposed and may shrink or expand due to heat. Therefore, in order to manufacture flexible devices, it is necessary to develop polyimide which can exhibit excellent thermal stability while maintaining high transparency at high temperature, in addition to excellent mechanical properties.

In order to solve the conventional problems,

A polyimide precursor prepared by using a diamine having a molecular weight of 4000 g / mol or more and a tetracarboxylic dianhydride having a structure represented by the following formula (1) in a molecular structure as a polymerization component; And

Wherein Log P is an organic solvent.

[Chemical Formula 1]

Wherein R ₁ and R ₂ are each independently a single bond, an alkylene group having 1 to 5 carbon atoms or a divalent aromatic group having 6 or more carbon atoms,

R ₃ , R ₄ , R ₅ and R ₆ are each independently an alkyl group of 1 to 5,

R ₇ , R ₈ , R ₉ and R ₁₀ are each independently an alkenyl group having 2 to 10 carbon atoms,

m ₁ and m ₂ are each independently an integer of 1 or more.

According to one embodiment, the molecular weight of the diamine having the structure of Formula 1 may be 4000 g / mol or more, preferably 4400 g / mol or more, and more preferably 5000 g / mol or more . When the molecular weight of the diamine having the structure of Formula 1 is less than 4000 g / mol, the heat resistance may be lowered. For example, when the glass transition temperature (Tg) of the produced polyimide is lowered or the thermal expansion coefficient is excessively high .

According to one embodiment, one or more diamines may be used in the present invention, and the diamine of Formula 1 may be contained in 1 to 20 mol%, preferably 1 to 10 mol%, of the total diamine.

According to one embodiment, the diamine of Formula 1 may be present in an amount of from 10 to 50% by weight, based on the total solid content of the polyimide precursor composition, that is, the weight of the polyimide precursor solids or the total weight of the polymerization components (diamine and acid dianhydride) By weight, preferably 10 to 40% by weight. If the diamine containing the structure of Formula 1 is added in an excess amount relative to the total weight of the polymer, for example, 50 wt% or more, or 40 wt% or more, mechanical properties such as modulus of the polyimide And the film strength is decreased, so that physical damage such as tearing of the film in the process can occur. When the diamine having the structure of Formula 1 is excessively added, Tg derived from the polymer having the siloxane structure may be exhibited. From this, Tg appears at a low process temperature of 350 DEG C or lower, In the inorganic film deposition process, wrinkles occur on the surface of the film due to the flow phenomenon of the polymer, and the inorganic film may be cracked.

As the solvent that can be used in the present invention, it is preferable to use an organic solvent having a positive Log P, specifically an amine-based solvent having a positive Log P value. For example, N, N-diethylacetamide (DEAc), N, N-diethylformamide (DEF) and N-ethylpyrrolidone , NEP). ≪ / RTI > The polyimide precursor composition according to the present invention can be obtained by using the organic solvent as described above, and it is possible to produce a polyimide precursor composition having a structure in which the structure of formula (1) The phenomenon can be reduced. Conventionally, two kinds of organic solvents are used to solve the above-mentioned phase separation. However, the present invention can reduce the whitening phenomenon by using only one kind of organic solvent, so that a more transparent polyimide film can be produced.

FIG. 1 briefly shows the principle of the present invention. As shown in FIG. 1A, the present invention can improve the modulus strength of polyimide and relieve stress caused by external force by inserting the structure of formula (1) containing a siloxane structure into the polyimide structure. At this time, the polyimide including the siloxane structure may exhibit polarity, and the polyimide structure not including the siloxane structure may undergo phase separation due to the difference in polarity. As a result, the siloxane structure may be unevenly distributed throughout the polyimide structure . In this case, it is difficult to improve the physical properties such as the strength improvement and stress relaxation effect of the polyimide due to the siloxane structure, and the transparency of the film may be deteriorated due to an increase in haze due to phase separation. In particular, in the case where the diamine containing a siloxane structure has a high molecular weight, the polyimide prepared from the diamine has a more pronounced polarity, and the phenomenon of phase separation between polyimides can be more clearly seen. However, when a siloxane diamine having a low molecular weight structure is used, a large amount of the siloxane diamine should be added in order to exhibit an effect such as stress relaxation as shown in FIG. 1B. Resulting in deterioration of the physical properties of the polyimide film. Thus, when a high molecular weight siloxane diamine is added, as shown in FIG. 1B, a relaxation segment can be formed in the molecule to a large extent. Therefore, the stress relaxation effect can be effectively exhibited even with a low content of a low molecular weight. Accordingly, the present invention has studied a method for making the diamine of formula (1) having a siloxane structure having a higher molecular weight distributed more uniformly on a polyimide matrix without phase separation.

In order to solve the above problem, there is a method of using a polar solvent and a non-polar solvent in combination. However, polar solvents tend to have high volatility, and thus may cause problems such as volatilization in advance in the manufacturing process. The reproducibility of the polyimide film may be deteriorated. In addition, the problem of phase separation may not be completely solved, and the haze of the produced polyimide film may be increased and transparency may be lowered. In the present invention, in order to uniformly distribute the polyimide structure having the structure represented by the formula (1) in the whole polyimide matrix, a solvent in which LogP is positive is used. In particular, an amine-based solvent having a positive LogP is used. More specifically, By using a solvent containing a structure having both hydrophilicity, it is possible not only to solve the process problem due to the use of a polar solvent but also to solve the problem of using a solvent of only one type due to the molecular structure having both hydrophilicity It is possible to provide a polyimide which is well suited for solving the problem due to phase separation and which has significantly improved haze characteristics.

According to one embodiment, the tetracarboxylic dianhydride may be selected from among tetracarboxylic dianhydrides containing a tetravalent organic group of the following general formula (2a) to (2i) in the molecular structure.

(2a)

(2b)

[Chemical Formula 2c]

(2d)

[Formula 2e]

(2f)

[Chemical Formula 2g]

(2i)

In formulas (2a) to (2i), R11 to R24 each independently represent a halogen atom selected from the group consisting of -F, -Cl, -Br and -I, a hydroxyl group (-OH), a thiol group May be a substituent selected from a group (-NO ₂ ), a cyano group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy group having 1 to 4 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms,

a3 is an integer of 0 to 8; a4 and a5 are each independently an integer of 0 to 3; and a7 and a8 are each independently an integer of 0 to 3 A15 and a16 are each independently an integer of 0 to 4, a17 and a18 are each independently an integer of 0 to 4, and a10 and a12 are each independently an integer of 0 to 3, a11 is an integer of 0 to 4, a6, a9, a13, a14, a19 and a20 are each independently an integer of 0 to 3,

n is an integer of 1 to 3,

A ₁₁ to A ₁₆ each independently represent -O-, -CR'R "-, -C (= O) -, -C (═O) O-, -C (═O) NH-, -SO ₂ -, phenylene group, and combinations thereof, wherein R 'and R "are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms Lt; / RTI >

In the present invention, as diamine in addition to the diamine of the above formula (1), diamines containing a divalent organic group represented by the following formula (3) in the molecular structure may be contained in an amount of 80 to 99 mol% in the total diamine content.

(3)

In Formula 3,

R ₃₁ and R ₃₂ each independently represent a halogen atom selected from the group consisting of -F, -Cl, -Br and -I, a hydroxyl group (-OH), a thiol group (-SH), a nitro group ₂ ), a cyano group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy group having 1 to 4 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 20 carbon atoms, , A halogenoalkyl group, an alkyl group, an aryl group, and a cyano group. For example, the halogen atom may be fluoro (-F), and the halogenoalkyl group may be a fluoroalkyl group having 1 to 10 carbon atoms including a fluoro group, such as a fluoromethyl group, a perfluoroethyl group, And the alkyl group may be selected from a methyl group, an ethyl group, a propyl group, an isopropyl group, a t-butyl group, a pentyl group and a hexyl group, and the aryl group may be selected from a phenyl group and a naphthalenyl group , And more preferably a fluoro atom and a fluoro atom such as a fluoroalkyl group.

Q is a single bond, -O-, -CR'R "-, -C (= O) -, -C (= O) O-, -C (= O) NH-, -S-, -SO 2 - , Phenylene group, and combinations thereof, wherein R 'and R "are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms Is selected.

Here, the 'fluoro-based substituent' of the present invention means not only a 'fluoro atom substituent' but also a 'substituent group containing a fluoro atom'.

The diamine of formula (3) may be selected from compounds represented by the following formulas (3a) to (3d).

In the above formulas (3a) to (3d), Q is as described above.

According to one embodiment, the tetracarboxylic dianhydride may include tetracarboxylic dianhydride having a structure represented by the following formula (4) in an amount of 20 to 80 mol% in the total tetracarboxylic dianhydride, Preferably 30 to 80 mol%, more preferably 30 to 70 mol%.

[Chemical Formula 4]

According to one embodiment, the tetracarboxylic dianhydride may include tetracarboxylic dianhydride having a structure represented by the following formula (5) in an amount of 20 to 80 mol% in the entire tetracarboxylic dianhydride, , Preferably 20 to 60 mol%, more preferably 20 to 50 mol%.

[Chemical Formula 5]

In Formula 5,

Q ₁ and Q ₂ is a single bond, each independently, -O-, -C (= O) -, -C (= O) O-, -C (= O) NH-, -S-, -SO 2 - , Phenylene group, and combinations thereof.

According to one embodiment, Formula 5 may be a compound of Formula 5a to 5e.

By including the repeating structure including the fluorene structure in the polyimide structure, the retardation in the thickness direction of the film can be reduced.

The present invention can use, together with the tetracarboxylic dianhydride of the above formula (4) or (5), at least one selected from the tetracarboxylic acid dianhydrides having the tetravalent organic group of the following formulas (6a) to (6r).

Wherein A ₂ is a group selected from the group consisting of a single bond, -O-, -C (= O) -, -C (= O) NH-, -S-, -SO ₂ - And v is an integer of 0 or 1, and in 6r, x is an integer of 1 to 10.

At least one hydrogen atom present in the tetravalent organic groups of 6a to 6r is a halogen atom selected from the group consisting of -F, -Cl, -Br and -I, a hydroxyl group (-OH), a thiol group -SH), a nitro group (-NO ₂ ), a cyano group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy group having 1 to 4 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms Lt; / RTI >

Alternatively, the present invention can use the tetracarboxylic dianhydrides of the above formulas (4) and (5) together. When the tetracarboxylic acid dianhydrides of the above formulas (4) and (5) are used together, the tetracarboxylic acid dianhydride The content of the tetracarboxylic dianhydride of the general formula (5) may be in the range of 10 to 30 mol%, preferably 10 to 25 mol%, more preferably 15 to 25 mol% with respect to the total content of water . The compound represented by the general formula (5) containing the fluorene structure is used in the production of the polyimide together with the compound represented by the general formula (4), thereby alleviating the heat shrinkage characteristics in the plane direction, The improvement of the phenomenon and the heat resistance such as the glass transition temperature can be improved.

According to one embodiment of the present invention, the total content of the tetracarboxylic dianhydride and the content of the diamine can be reacted in a molar ratio of 1: 1.1 to 1.1: 1, and preferably the reactivity is improved and the processability is improved It is preferable that the total content of the tetracarboxylic dianhydride is excessively reacted with respect to the diamine or that the content of the diamine is excessively reacted with respect to the total content of the tetracarboxylic dianhydride.

According to one embodiment of the present invention, it is preferable that the molar ratio of the total content of the tetracarboxylic dianhydride to the content of the diamine is 1: 0.99 to 0.99: 1, preferably 1: 0.98 to 0.98: 1 .

The organic solvent that can be used in the polymerization reaction may be a positive integer having a partition coefficient (Log P value) at 25 ° C and a boiling point of 180 ° C or less. More specifically, the LogP value may be 0.01 to 3, 2, or 0.01 to 1.

The partition coefficient can be calculated using the ACD / LogP module of the ACD / Percepta platform of ACD / Labs. The ACD / LogP module can calculate the quantitative structure-property relationship (QSPR) .

When the distribution coefficient value is a positive number, it means that the polarity of the solvent is hydrophobic. According to the study of the present inventors, a polyimide precursor composition was prepared using a specific solvent having a positive distribution coefficient and the polyimide precursor composition , The curling property of the solution is improved. Further, by using a solvent having a positive Log P as described above, the present invention can control the liquid curl of a solution without using an additive that controls the surface tension of the material such as a leveling agent and the smoothness of the film, This is because it does not use an additive such as an additive and thus it is possible to eliminate the quality and process problems such as the inclusion of a low molecular substance in the final product and to form a polyimide film having more uniform properties .

For example, in the step of coating a polyimide precursor composition on a glass substrate, the solution may be curled due to shrinkage of the coating layer during curing or under the condition of leaving the coating solution in a humidity condition. Liquid curling of such a coating solution may lead to a variation in the thickness of the film. As a result, the film is broken due to the lack of bending resistance of the film, or the edge is broken when cutting, resulting in poor workability in the process, Problems can arise.

Further, in the case of a polyimide precursor composition comprising a polar solvent having a polarity of Log P being negative when a fine foreign substance having polarity is introduced on a polyimide precursor composition coated on a substrate, the position of the foreign substance is determined by the polarity of the foreign substance The cracks or the thickness of the coating may be sporadic. However, when a hydrophobic solvent having a positive log P is used, the occurrence of a change in thickness due to cracking of the coating is reduced even when a foreign substance having polarity is introduced. Can be suppressed.

Specifically, the polyimide precursor composition comprising a solvent having a positive logarithm of Log P may have a percent coverage of 0% to 0.1% or less as defined by the following formula (1).

[Formula 1]

Curling rate (%) = [(A-B) / A] x 100

In the above formula (1)

A: An area of the polyimide precursor composition coated on a substrate (100 mm x 100 mm)

B: Area after curling occurs from the edge of the polyimide precursor composition or the substrate coated with the PI film

The liquid curl phenomenon of the polyimide precursor composition and the film may occur within 30 minutes after coating the solution of the polyimide precursor composition, and in particular, the thickness of the edge can be made thick by starting to dry from the edge.

After coating the substrate with the polyimide precursor composition according to the present invention, the coated resin composition solution is allowed to stand in a humidity condition for 10 minutes or more, for example, 10 minutes or more, for example, 40 minutes or more for a drying rate of 0.1 50%, 60%, 70% or more of the humidity condition in the range of 40% to 80%, for example, at a temperature of 20 to 30 DEG C, , Even after being left for 10 to 50 minutes under a humidity condition of 50%, for example, at a humidity of 80%, and a humidity of 0.1% or less, preferably 0.05% It is possible to show a curling rate close to 0%.

For example, the polyimide precursor composition is coated on a substrate and then dried at a temperature of at least 10 minutes, for example, at a temperature of 20 to 30 DEG C under a humidity condition of 40% or more, more specifically, Is left for 10 to 50 minutes under a humidity condition ranging from 40% to 80%, that is, at a humidity condition of, for example, 40%, 50%, 60%, 70% The curling rate of the polyimide film may be 0.1% or less, that is, the curling process may hardly occur or disappear even in the curing process by the heat treatment, and specifically, the curling rate close to 0.05%, more preferably nearly 0% .

The polyimide precursor composition according to the present invention can solve this liquid curl phenomenon, thereby making it possible to obtain a polyimide film having more uniform characteristics, thereby further improving the yield of the production process.

In addition, the density of the solvent according to the present invention may be 1 g / cm ³ or less as measured by the standard measurement method of ASTM D1475, and if the density is 1 or more, the relative viscosity may be increased and the efficiency of the process may decrease .

The reaction of the tetracarboxylic acid dianhydride with the diamine can be carried out according to a conventional method for producing a polyimide precursor polymerization such as solution polymerization. Specifically, it can be produced by dissolving a diamine in an organic solvent, and then adding a tetracarboxylic acid dianhydride to the resultant mixed solution to perform a polymerization reaction.

According to one embodiment,

a) introducing the diamine of formula 1 into an organic solvent;

b) introducing the diamine of formula (3) into the solution prepared in step a);

c) introducing at least one tetracarboxylic dianhydride in the solution prepared in step b); And

d) polymerizing the solution prepared in step c) at a predetermined reaction temperature.

The reaction can be carried out under an inert gas or a nitrogen stream and can be carried out under anhydrous conditions.

The reaction temperature during the polymerization reaction may be -20 to 80 ° C, preferably 0 to 80 ° C. If the reaction temperature is too high, the reactivity may become high and the molecular weight may become large, and the viscosity of the precursor composition may increase, which may be disadvantageous in the process.

The polyimide precursor composition produced according to the above-described production method preferably contains a solid content in an amount such that the composition has an appropriate viscosity in consideration of processability such as coating properties during the film forming process. According to one embodiment, the content of the composition can be controlled so that the total polyimide precursor content is 8 to 25 wt%, preferably 10 to 25 wt%, more preferably 10 to 20 wt% have.

Alternatively, the polyimide precursor composition may be adjusted to have a viscosity of 3,000 cP or more, or 4,000 cP or more, and the viscosity of the polyimide precursor composition is 10,000 cP or less, preferably 9,000 cP or less, more preferably 8,000 cP or less Of the total weight of the composition. When the viscosity of the polyimide precursor composition exceeds 10,000 cP, the efficiency of defoaming at the time of processing the polyimide film is lowered. As a result, not only the process efficiency but also the surface roughness of the produced film is poor due to bubbling, so that the electrical, optical and mechanical properties Can be degraded.

The molecular weight of the polyimide according to the present invention may be 10,000 to 200,000 g / mol, or 20,000 to 100,000 g / mol, or 30,000 to 100,000 g / mol. The molecular weight distribution (Mw / Mn) of the polyimide according to the present invention is preferably 1.1 to 2.5. If the weight average molecular weight or the molecular weight distribution of the polyimide is out of the above range, film formation may be difficult or characteristics of the polyimide-based film such as transparency, heat resistance and mechanical properties may be deteriorated.

Next, the polyimide precursor obtained as a result of the polymerization reaction is imidized to prepare a transparent polyimide film. At this time, the imidization process may be specifically a chemical imidization or thermal imidization process.

For example, after adding a dehydrating agent and an imidation catalyst to the polymerized polyimide precursor composition, the polymerized polyimide precursor composition is heated to a temperature of 50 to 100 ° C and imidized by a chemical reaction, or alcohol is removed by refluxing the solution, Polyimide can be obtained by heating.

In the above chemical imidization method, pyridine, triethylamine, picoline or quinoline may be used as the imidization catalyst. In addition, a nitrogen-containing heterocyclic compound substituted or unsubstituted, a nitrogen-containing heterocyclic compound N- A substituted or unsubstituted amino acid compound, an aromatic hydrocarbon compound having a hydroxyl group or an aromatic heterocyclic compound, particularly 1,2-dimethylimidazole, N-methylimidazole, N-benzyl- Lower alkyl imidazole such as methyl imidazole, 2-methyl imidazole, 2-ethyl-4-methyl imidazole and 5-methylbenzimidazole, and N-benzyl- Substituted pyridines such as pyridine, pyridine, pyridine, isothiazole, isothiazole, isothiazole, isoquinoline, 3,5-dimethylpyridine, 3,4-dimethylpyridine, 2,5-dimethylpyridine, 2,4-dimethylpyridine and 4- May be used.

As the dehydrating agent, an acid anhydride such as acetic anhydride may be used.

Alternatively, the polyimide precursor composition can be imidized by applying the polyimide precursor composition onto a substrate and then heat-treating the polyimide precursor composition.

The polyimide precursor composition may be in the form of a solution dissolved in an organic solvent. When the polyimide precursor composition has such a form, for example, when the polyimide precursor is synthesized in an organic solvent, the solution may be the reaction solution itself to be obtained, The reaction solution may be diluted with another solvent. When the polyimide precursor is obtained as a solid powder, it may be dissolved in an organic solvent to form a solution.

The present invention provides a method for preparing a polyimide precursor composition, comprising: applying the polyimide precursor composition onto a substrate;

And heat treating the applied polyimide precursor composition. The present invention also provides a method for producing a polyimide film.

The polyimide precursor composition is coated on a substrate and heat-treated on an IR oven, a hot air oven or a hot plate. The heat treatment temperature may range from 300 to 500 ° C, preferably from 320 to 480 ° C, May be carried out by a multi-stage heating process. The heat treatment process may be performed for 20 to 70 minutes, and preferably for 20 to 60 minutes.

The organic solvent contained in the polyimide precursor composition of the present invention may be the same as the organic solvent used in the synthesis reaction.

In the present invention, a silane coupling agent, a crosslinkable compound, an imidization accelerator for promoting imidization efficiently, and the like may be added as long as the effect is not impaired.

In addition, the polyimide-based film can have a haze value of haze of 2 or less, preferably 1 or less, or 0.9 or less, thereby providing a polyimide film with improved transparency. At this time, the thickness of the polyimide film may be 8 to 15 탆, preferably 10 to 12 탆.

Further, it is preferable that the transmittance to light at a wavelength of 380 to 760 nm is 80% or more and the yellowness degree (YI) is about 15 or less, preferably about 10 or less, more preferably about 8 or less Lt; RTI ID = 0.0 > polyimide < / RTI > By having excellent light transmittance and yellowness as described above, it is possible to exhibit significantly improved transparency and optical characteristics.

The polyimide-based film preferably has an in-plane retardation (R _in ) of about 0 to 100 nm, a retardation value (R _th ) in the thickness direction of about 1000 nm or less, or 0 to 700 nm, preferably 0 to 600 nm Lt; RTI ID = 0.0 > nm. ≪ / RTI > The retardation in the thickness direction can exhibit visual sensibility suitable for display. When the retardation in the thickness direction is 1000 nm or more, a phase difference is generated in the polyimide film, and the light is distorted, so that the visibility can be remarkably lowered.

The polyimide film according to the present invention may have a glass transition temperature (Tg) of 350 ° C or higher, preferably 360 ° C or higher, and more preferably 370 ° C or higher.

In addition, the polyimide film according to the present invention may have excellent thermal stability depending on the temperature change. For example, the polyimide film according to the present invention may have a thermal expansion coefficient of -10 To 100 ppm / 占 폚, preferably from -7 to 90 ppm / 占 폚, more preferably 80 ppm / 占 폚 or lower.

In another embodiment of the present invention, there is provided a molded article comprising the polyimide copolymer.

The molded article may be a film, a fiber, a coating material, an adhesive, and the like, but is not limited thereto. The molded article may be formed by a dry-wet method, a dry method, a wet method, or the like using a composite composition of the copolymer and the inorganic particles, but is not limited thereto. Specifically, as described above, the molded article may be an optical film. In this case, the composition containing the polyimide copolymer may be applied to a substrate by a method such as spin coating, and then dried and cured .

The polyimide according to the present invention can maintain the properties such as heat resistance and mechanical strength due to the rigid structure as it is and can exhibit excellent heat resistance against the heat shrinkage behavior that may occur during the high temperature process, And it can be used as a substrate for an element, a cover substrate for a display, an optical film, an IC (integrated circuit) package, an adhesive film, a multilayer flexible printed circuit (FPC) Protective films for optical discs, and the like,

According to another embodiment of the present invention, there is provided a display device including the molded article. Specifically, the display device may be a liquid crystal display device (LCD), an organic light emitting diode (OLED), or the like. In particular, a low emperature polysilane (LTPS) , But is not limited thereto.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

≪ Example 1 >

DMS (Diphenylsiloxane-dimethylsiloxane co-oligomer, DPS-DMS, DPS-DMS) was prepared by charging 96 g of N, N-diethylacetamide (DEAc) (Molecular weight: 4400 g / mol) and 0.0304 mol of TFMB (2,2'-bis (trifluoromethyl) benzidine) were added and dissolved at the same temperature. To the solution containing DPS-DMS and TFMB, 0.0321 mol of PMDA (pyromellitic dianhydride) was added at the same temperature as above, and the mixture was stirred for 3 hours and then at 80 ° C for 4 hours.

≪ Example 2 >

Except that 0.0011 mol of DPS-DMS, 0.0141 mol of TFMB and 0.0153 mol of BPAF instead of 0.00167 mol of DPS-DMS, 0.0304 mol of TFMB and 0.0321 mol of PMDA were used.

≪ Example 3 >

Except that 0.0014 mol of DPS-DMS, 0.0212 mol of TFMB and 0.0226 mol of ODPA were used instead of 0.00167 mol of DPS-DMS, 0.0304 mol of TFMB and 0.0321 mol of PMDA.

<Example 4>

Except that 0.001 mol of DPS-DMS, 0.009 mol of TFMB and 0.01 mol of TBIS-BAN were used instead of 0.00167 mol of DPS-DMS, 0.0304 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Example 5 >

Except that 0.0011 mol of DPS-DMS, 0.0146 mol of TFMB and 0.0158 mol of 6FDA instead of 0.00167 mol of DPS-DMS, 0.0304 mol of TFMB and 0.0321 mol of PMDA were used.

&Lt; Example 6 >

Except that 0.00167 mol of DPS-DMS, 0.0304 mol of TFMB, 0.0321 mol of PMDA, 0.0016 mol of DPS-DMS, 0.0296 mol of TFMB and 0.0312 mol of PMDA-H were used.

&Lt; Example 7 >

Except that 0.0018 mol of DPS-DMS, 0.0339 mol of TFMB and 0.0357 mol of CBDA were used instead of 0.00167 mol of DPS-DMS, 0.0304 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Example 8 >

Except that 0.0011 mol of DPS-DMS, 0.0141 mol of TFMB and 0.0152 mol of TAHQ were used instead of 0.00167 mol of DPS-DMS, 0.0304 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Example 9 >

Except that 0.0013 mol of DPS-DMS, 0.0183 mol of TFMB and 0.0195 mol of DSDA were used instead of 0.00167 mol of DPS-DMS, 0.0304 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Comparative Example 1 &

 After 96 g of NMP (N-Methylpyrrolidone) (distribution coefficient -0.28) was filled in a stirrer through which a nitrogen stream was flowing, a diphenylsiloxane-dimethylsiloxane co-oligomer (DPS-DMS) 4400 g / mol) and 0.0304 mol of TFMB (2,2'-bis (trifluoromethyl) benzidine) were dissolved at the same temperature. 0.0321 mol of PMDA (pyromellitic dianhydride) was added to the DPS-DMS and TFMB-added solution at the same temperature, followed by stirring for 3 hours and then at 80 ° C for 4 hours.

&Lt; Comparative Example 2 &

Except that 0.0011 mol of DPS-DMS, 0.00141 mol of TFMB and 0.0153 mol of BPAF were used instead of 0.0017 mol of DPS-DMS, 0.0304 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Comparative Example 3 &

Except that 0.0014 mol of DPS-DMS, 0.0212 mol of TFMB and 0.0226 mol of ODPA were used instead of 0.0017 mol of DPS-DMS, 0.0304 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Comparative Example 4 &

Except that 0.001 mol of DPS-DMS, 0.009 mol of TFMB and 0.01 mol of TBIS-BAN were used instead of 0.0017 mol of DPS-DMS, 0.0304 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Comparative Example 5 &

Except that 0.0011 mol of DPS-DMS, 0.0146 mol of TFMB and 0.0158 mol of 6FDA were used instead of 0.0017 mol of DPS-DMS, 0.0304 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Comparative Example 6 >

Except that 0.0016 mol of DPS-DMS, 0.0296 mol of TFMB and 0.0312 mol of PMDA-H were used instead of 0.0017 mol of DPS-DMS, 0.0304 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Comparative Example 7 &

Except that 0.0018 mol of DPS-DMS, 0.0339 mol of TFMB and 0.0357 mol of CBDA were used instead of 0.0017 mol of DPS-DMS, 0.0304 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Comparative Example 8 >

Except that 0.0011 mol of DPS-DMS, 0.0141 mol of TFMB and 0.0152 mol of TAHQ were used instead of 0.0017 mol of DPS-DMS, 0.0304 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Comparative Example 9 &

Except that 0.0013 mol of DPS-DMS, 0.0183 mol of TFMB and 0.0195 mol of DSDA were used instead of 0.0017 mol of DPS-DMS, 0.0304 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Example 10 >

DMS (Diphenylsiloxane-dimethylsiloxane co-oligomer, DPS-DMS, DPS-DMS) was prepared by adding 100 g of N, N-diethylacetamide (DEAc) (Molecular weight: 5000 g / mol) and 0.0306 mol of TFMB (2,2'-bis (trifluoromethyl) benzidine) were dissolved at the same temperature. 0.03211 mol of PMDA (pyromellitic dianhydride) was added to the solution to which DPS-DMS and TFMB were added at the same temperature, and the mixture was stirred for 3 hours and then at 80 ° C for 4 hours.

&Lt; Example 11 >

Except that 0.001 mol of DPS-DMS, 0.0143 mol of TFMB and 0.0153 mol of BPAF were used instead of 0.0014 mol of DPS-DMS, 0.0306 mol of TFMB and 0.03211 mol of PMDA.

&Lt; Example 12 >

Except that 0.0012 mol of DPS-DMS, 0.0213 mol of TFMB and 0.0226 mol of ODPA were used instead of 0.0014 mol of DPS-DMS, 0.0306 mol of TFMB and 0.03211 mol of PMDA.

&Lt; Example 13 >

Except that 0.009 mol of DPS-DMS, 0.0092 mol of TFMB and 0.01 mol of TBIS-BAN were used instead of 0.0014 mol of DPS-DMS, 0.0306 mol of TFMB and 0.03211 mol of PMDA.

&Lt; Example 14 >

Except that 0.001 mol of DPS-DMS, 0.0147 mol of TFMB and 0.0158 mol of 6FDA instead of 0.0014 mol of DPS-DMS, 0.0306 mol of TFMB and 0.03211 mol of PMDA were used.

&Lt; Example 15 >

Except that 0.0014 mol of DPS-DMS, 0.0298 mol of TFMB and 0.0312 mol of PMDA-H instead of 0.0014 mol of DPS-DMS, 0.0306 mol of TFMB and 0.03211 mol of PMDA were used.

&Lt; Example 16 >

Except that 0.0023 mol of DPS-DMS, 0.0334 mol of TFMB and 0.0357 mol of CBDA were used instead of 0.0014 mol of DPS-DMS, 0.0306 mol of TFMB and 0.03211 mol of PMDA.

&Lt; Example 17 >

Except that 0.001 mol of DPS-DMS, 0.0142 mol of TFMB and 0.0152 mol of TAHQ were used instead of 0.0014 mol of DPS-DMS, 0.0306 mol of TFMB and 0.03211 mol of PMDA.

&Lt; Example 18 >

Except that 0.0011 mol of DPS-DMS, 0.0184 mol of TFMB and 0.0195 mol of DSDA were used instead of 0.0014 mol of DPS-DMS, 0.0306 mol of TFMB and 0.03211 mol of PMDA.

&Lt; Comparative Example 10 &

 (DPS-DMS, molecular weight: 5000 g / mol) 0.0014 (molecular weight: 5,000 g / mol) in a nitrogen gas stream while maintaining the temperature of the reactor at 25 ° C. and 0.0306 mol of TFMB (2,2'-bis (trifluoromethyl) benzidine) were dissolved at the same temperature. 0.03211 mol of PMDA (pyromellitic dianhydride) was added to the solution to which DPS-DMS and TFMB were added at the same temperature, and the mixture was stirred for 3 hours and then at 80 ° C for 4 hours.

&Lt; Comparative Example 11 &

Except that 0.001 mol of DPS-DMS, 0.0143 mol of TFMB and 0.0153 mol of BPAF were used instead of 0.0014 mol of DPS-DMS, 0.0306 mol of TFMB and 0.03211 mol of PMDA.

&Lt; Comparative Example 12 >

Except that 0.0012 mol of DPS-DMS, 0.0213 mol of TFMB and 0.0226 mol of ODPA were used instead of 0.0014 mol of DPS-DMS, 0.0306 mol of TFMB and 0.03211 mol of PMDA.

&Lt; Comparative Example 13 &

Except that 0.009 mol of DPS-DMS, 0.0092 mol of TFMB and 0.01 mol of TBIS-BAN were used instead of 0.0014 mol of DPS-DMS, 0.0306 mol of TFMB and 0.03211 mol of PMDA.

&Lt; Comparative Example 14 >

Except that 0.001 mol of DPS-DMS, 0.0147 mol of TFMB and 0.0158 mol of 6FDA instead of 0.0014 mol of DPS-DMS, 0.0306 mol of TFMB and 0.03211 mol of PMDA were used.

&Lt; Comparative Example 15 &

Except that 0.0014 mol of DPS-DMS, 0.0298 mol of TFMB and 0.0312 mol of PMDA-H were used instead of 0.0014 mol of DPS-DMS, 0.0306 mol of TFMB and 0.03211 mol of PMDA.

&Lt; Comparative Example 16 >

Except that 0.0023 mol of DPS-DMS, 0.0334 mol of TFMB and 0.0357 mol of CBDA were used instead of 0.0014 mol of DPS-DMS, 0.0306 mol of TFMB and 0.03211 mol of PMDA, respectively.

&Lt; Comparative Example 17 >

Except that 0.001 mol of DPS-DMS, 0.0142 mol of TFMB and 0.0152 mol of TAHQ were used instead of 0.0014 mol of DPS-DMS, 0.0306 mol of TFMB and 0.03211 mol of PMDA.

&Lt; Comparative Example 18 >

Except that 0.0011 mol of DPS-DMS, 0.0184 mol of TFMB and 0.0195 mol of DSDA were used instead of 0.0014 mol of DPS-DMS, 0.0306 mol of TFMB and 0.03211 mol of PMDA.

&Lt; Example 19 >

137 g of N, N-diethylacetamide (DEAc) (partition coefficient: 0.32) was charged into a stirrer through which nitrogen gas flow was passed. The reactor was maintained at 25 ° C and a two-terminal amine-modified PDMS-DMS (Diphenylsiloxane-dimethylsiloxane co- Molecular weight 5700 g / mol) and 0.0308 mol of TFMB (2,2'-bis (trifluoromethyl) benzidine) were dissolved at the same temperature. 0.0321 mol of PMDA (pyromellitic dianhydride) was added to the PDMS and TFMB-added solution at the same temperature, and the mixture was stirred for 3 hours and then at 80 ° C for 4 hours.

&Lt; Example 20 >

Except that 0.0013 mol of DPS-DMS, 0.0308 mol of TFMB, 0.0321 mol of PMDA, 0.0009 mol of DPS-DMS, 0.0144 mol of TFMB and 0.0153 mol of BPAF were used.

&Lt; Example 21 >

Except that 0.001 mol of DPS-DMS, 0.0215 mol of TFMB and 0.0226 mol of ODPA were used instead of 0.0013 mol of DPS-DMS, 0.0308 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Example 22 >

Except that 0.0013 mol of DPS-DMS, 0.0093 mol of TFMB and 0.01 mol of TBIS-BAN were used instead of 0.0013 mol of DPS-DMS, 0.0308 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Example 23 >

Except that 0.0013 mol of DPS-DMS, 0.0308 mol of TFMB, 0.0321 mol of PMDA, 0.0009 mol of DPS-DMS, 0.0149 mol of TFMB and 0.0158 mol of 6FDA were used.

&Lt; Example 24 >

Except that 0.0012 mol of DPS-DMS, 0.03 mol of TFMB and 0.0312 mol of PMDA-H were used instead of 0.0013 mol of DPS-DMS, 0.0308 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Example 25 >

Except that 0.0013 mol of DPS-DMS, 0.0334 mol of TFMB and 0.0357 mol of CBDA were used instead of 0.0013 mol of DPS-DMS, 0.0308 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Example 26 >

Except that 0.0013 mol of DPS-DMS, 0.0308 mol of TFMB, 0.0321 mol of PMDA, 0.0009 mol of DPS-DMS, 0.0144 mol of TFMB and 0.0152 mol of TAHQ were used.

&Lt; Example 27 >

Except that 0.001 mol of DPS-DMS, 0.0186 mol of TFMB and 0.0195 mol of DSDA were used instead of 0.0013 mol of DPS-DMS, 0.0308 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Comparative Example 19 >

 137 g of NMP (partition coefficient: -0.28) was filled in a stirrer through which nitrogen gas flow was passed. Then, 0.0013 (molecular weight, 5700 g / mol) of DMP-DMS (Diphenylsiloxane-dimethylsiloxane co- and 0.0308 mol of TFMB (2,2'-bis (trifluoromethyl) benzidine) were dissolved at the same temperature. 0.0321 mol of PMDA (pyromellitic dianhydride) was added to the DPS-DMS and TFMB-added solution at the same temperature, followed by stirring for 3 hours and then at 80 ° C for 4 hours.

&Lt; Comparative Example 20 &

Except that 0.0013 mol of DPS-DMS, 0.0308 mol of TFMB, 0.0321 mol of PMDA, 0.0009 mol of DPS-DMS, 0.0144 mol of TFMB and 0.0153 mol of BPAF were used.

&Lt; Comparative Example 21 &

Except that 0.001 mol of DPS-DMS, 0.0215 mol of TFMB and 0.0226 mol of ODPA were used instead of 0.0013 mol of DPS-DMS, 0.0308 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Comparative Example 22 >

Except that 0.0013 mol of DPS-DMS, 0.0093 mol of TFMB and 0.01 mol of TBIS-BAN were used instead of 0.0013 mol of DPS-DMS, 0.0308 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Comparative Example 23 >

Except that 0.0013 mol of DPS-DMS, 0.0308 mol of TFMB, 0.0321 mol of PMDA, 0.0009 mol of DPS-DMS, 0.0149 mol of TFMB and 0.0158 mol of 6FDA were used.

&Lt; Comparative Example 24 >

Except that 0.0012 mol of DPS-DMS, 0.03 mol of TFMB and 0.0312 mol of PMDA-H were used instead of 0.0013 mol of DPS-DMS, 0.0308 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Comparative Example 25 >

Except that 0.0013 mol of DPS-DMS, 0.0334 mol of TFMB and 0.0357 mol of CBDA were used instead of 0.0013 mol of DPS-DMS, 0.0308 mol of TFMB and 0.0321 mol of PMDA.

&Lt; Comparative Example 26 >

Except that 0.0013 mol of DPS-DMS, 0.0308 mol of TFMB, 0.0321 mol of PMDA, 0.0009 mol of DPS-DMS, 0.0144 mol of TFMB and 0.0152 mol of TAHQ were used.

&Lt; Comparative Example 27 >

Except that 0.001 mol of DPS-DMS, 0.0186 mol of TFMB and 0.0195 mol of DSDA were used instead of 0.0013 mol of DPS-DMS, 0.0308 mol of TFMB and 0.0321 mol of PMDA.

<Experimental Example 1>

The polyimide precursor compositions prepared in Examples 1 to 27 and Comparative Examples 2 to 27 were spin coated on a glass substrate to a thickness of 9.5 to 11 탆. The glass substrate coated with the polyimide precursor composition was placed in an oven and heated at a rate of 2 占 폚 / min. While maintaining at 80 占 폚 for 15 minutes, 150 占 폚 for 30 minutes, 220 占 폚 for 30 minutes, and 400 占 폚 for 1 hour, The process was carried out. After completion of the curing process, the glass substrate was immersed in water, and the film formed on the glass substrate was peeled off and dried at 100 DEG C in an oven to prepare a polyimide film.

The haze was measured by the method according to ASTM D1003 using Haze Meter HM-150, and the results are shown in Tables 1 to 6.

Acid anhydride
(A) Diamine
(B) DPS
-DMS Mw
(C) Organic solvent DPS-DMS wt% Solids
density% thickness
(μm) Hayes
(Haze) Example 1 PMDA TFMB 4400 DEAc 30 19 10 0.3 Example 2 BPAF TFMB 4400 DEAc 30 19 10 0.2 Example 3 ODPA TFMB 4400 DEAc 30 19 10 0.35 Example 4 TBIS-BAN TFMB 4400 DEAc 30 19 10 0.4 Example 5 6FDA TFMB 4400 DEAc 30 19 10 0.55 Example 6 PMDA-H TFMB 4400 DEAc 30 19 10 0.65 Example 7 CBDA TFMB 4400 DEAc 30 19 10 0.7 Example 8 TAHQ TFMB 4400 DEAc 30 19 10 0.84 Example 9 DSDA TFMB 4400 DEAc 30 19 10 0.6

Acid anhydride
(A) Diamine
(B) DPS
-DMS Mw
(C) Organic solvent DPS
-DMS wt% Solid wt% thickness
(μm) Hayes
(Haze) Comparative Example 1 PMDA TFMB 4400 NMP 30 19 10 60 Comparative Example 2 BPAF TFMB 4400 NMP 30 19 10 65 Comparative Example 3 ODPA TFMB 4400 NMP 30 19 10 60 Comparative Example 4 TBIS-BAN TFMB 4400 NMP 30 19 10 61 Comparative Example 5 6FDA TFMB 4400 NMP 30 19 10 64 Comparative Example 6 PMDA-H TFMB 4400 NMP 30 19 10 60 Comparative Example 7 CBDA TFMB 4400 NMP 30 19 10 63 Comparative Example 8 TAHQ TFMB 4400 NMP 30 19 10 67 Comparative Example 9 DSDA TFMB 4400 NMP 30 19 10 68

Acid anhydride
(A) Diamine
(B) DPS
-DMS Mw
(C) Organic solvent DPS
-DMS wt% Solid content concentration% thickness
(μm) Hayes
(Haze) Example 10 PMDA TFMB 5000 DEAc 30 19 10 0.7 Example 11 BPAF TFMB 5000 DEAc 30 19 10 0.85 Example 12 ODPA TFMB 5000 DEAc 30 19 10 0.35 Example 13 TBIS-BAN TFMB 5000 DEAc 30 19 10 0.64 Example 14 6FDA TFMB 5000 DEAc 30 19 10 0.45 Example 15 PMDA-H TFMB 5000 DEAc 30 19 10 0.5 Example 16 CBDA TFMB 5000 DEAc 30 19 10 0.74 Example 17 TAHQ TFMB 5000 DEAc 30 19 10 0.6 Example 18 DSDA TFMB 5000 DEAc 30 19 10 0.78

Acid anhydride
(A) Diamine
(B) DPS
-DMS Mw
(C) abandonment
menstruum DPS
-DMS content% Solid content concentration% thickness
(μm) Hayes
(Haze) Comparative Example 10 PMDA TFMB 5000 NMP 30 19 10 70 Comparative Example 11 BPAF TFMB 5000 NMP 30 19 10 75 Comparative Example 12 ODPA TFMB 5000 NMP 30 19 10 73 Comparative Example 13 TBIS-BAN TFMB 5000 NMP 30 19 10 76 Comparative Example 14 6FDA TFMB 5000 NMP 30 19 10 71 Comparative Example 15 PMDA-H TFMB 5000 NMP 30 19 10 72 Comparative Example 16 CBDA TFMB 5000 NMP 30 19 10 78 Comparative Example 17 TAHQ TFMB 5000 NMP 30 19 10 79 Comparative Example 18 DSDA TFMB 5000 NMP 30 19 10 75

Acid anhydride
(A) Diamine
(B) DPS
-DMS Mw
(C) abandonment
menstruum PDMS content% Solid content concentration% thickness
(μm) Hayes
(Haze) Example 19 PMDA TFMB 5700 DEAc 30 19 10 0.55 Example 20 BPAF TFMB 5700 DEAc 30 19 10 0.45 Example 21 ODPA TFMB 5700 DEAc 30 19 10 0.65 Example 22 TBIS-BAN TFMB 5700 DEAc 30 19 10 0.63 Example 23 6FDA TFMB 5700 DEAc 30 19 10 0.67 Example 24 PMDA-H TFMB 5700 DEAc 30 19 10 0.75 Example 25 CBDA TFMB 5700 DEAc 30 19 10 0.75 Example 26 TAHQ TFMB 5700 DEAc 30 19 10 0.85 Example 27 DSDA TFMB 5700 DEAc 30 19 10 0.88

Acid anhydride
(A) Diamine
(B) DPS
-DMS Mw
(C) abandonment
menstruum PDMS content% Solid content concentration% thickness
(μm) Hayes
(Haze) Comparative Example 19 PMDA TFMB 5700 NMP 30 19 10 83 Comparative Example 20 BPAF TFMB 5700 NMP 30 19 10 80 Comparative Example 21 ODPA TFMB 5700 NMP 30 19 10 82 Comparative Example 22 TBIS-BAN TFMB 5700 NMP 30 19 10 83 Comparative Example 23 6FDA TFMB 5700 NMP 30 19 10 84 Comparative Example 24 PMDA-H TFMB 5700 NMP 30 19 10 75 Comparative Example 25 CBDA TFMB 5700 NMP 30 19 10 73 Comparative Example 26 TAHQ TFMB 5700 NMP 30 19 10 76 Comparative Example 27 DSDA TFMB 5700 NMP 30 19 10 74

TFMB: 2,2'-bis (trifluoromethyl) benzidine

DPS-DMS: Diphenylsiloxane-dimethylsiloxane co-oligomer

PMDA: Pyromellitic Dianhydride

BPAF: 9,9'-bis (3,4-dicarboxyphenyl) fluorene dianhydride

ODPA: 4,4'-Oxydiphthalic anhydride

TBIS-BAN: 1,1'-Bis (3 ', 4'-dicarboxybenzoylamino) -9,9'-diphenylofluorene dianhydride

6FDA: 4,4 '- (Hexafluoroisopropylidene) diphthalic anhydride

PMDA-H: cyclohexane-1,2,4,5-tetracarboxylic dianhydride

CBDA: Cyclobutane-1,2,3,4-tetracarboxylic dianhydride

TAHQ: bis (trimellitic acid anhydride) phenyl ester

DSDA: 3,3 ', 4,4'-Diphenylsulfone tetracarboxylic dianhydride

As shown in Tables 1 to 6, the polyimide film prepared from the polyimide precursor composition according to the present invention was prepared by preparing a transparent polyimide film having a significantly reduced haze compared with the polyimide precursor composition of Comparative Examples 1 to 27 can do.

&Lt; Example 28 >

N-diethylacetamide (DEAc) (partition coefficient: 0.32) (164 g) was charged into a stirrer through which a nitrogen stream was flowing. The reactor was maintained at a temperature of 25 ° C and a double terminal amine-modified DPS-DMS (Diphenylsiloxane-dimethylsiloxane co- (Molecular weight: 5700 g / mol) and 0.0520 mol of TFMB (2,2'-bis (trifluoromethyl) benzidine) were added and dissolved at the same temperature. 0.0321 mol of PMDA and 0.0214 mol of 9,9'-bis (3,4-dicaroxyphenyl) fluorene dianhydride) were added to the PDMS and TFMB-added solution at the same temperature, and the mixture was stirred for 3 hours, Lt; / RTI &gt;

&Lt; Example 29 >

N-diethylacetamide (DEAc) (partition coefficient: 0.32) (164 g) was charged into a stirrer through which a nitrogen stream was flowing. The reactor was maintained at a temperature of 25 ° C and a double terminal amine-modified DPS-DMS (Diphenylsiloxane-dimethylsiloxane co- (Molecular weight: 5000 g / mol) and 0.0518 mol of TFMB (2,2'-bis (trifluoromethyl) benzidine) were dissolved at the same temperature. 0.0321 mol of PMDA and 0.0214 mol of 9,9'-bis (3,4-dicaroxyphenyl) fluorene dianhydride) were added to the PDMS and TFMB-added solution at the same temperature, and the mixture was stirred for 3 hours, Lt; / RTI &gt;

&Lt; Example 30 >

N-diethylacetamide (DEAc) (partition coefficient: 0.32) (164 g) was charged into a stirrer through which a nitrogen stream was flowing. The reactor was maintained at a temperature of 25 ° C and a double terminal amine-modified DPS-DMS (Diphenylsiloxane-dimethylsiloxane co- (Molecular weight: 4400 g / mol) and 0.0516 mol of TFMB (2,2'-bis (trifluoromethyl) benzidine) were added and dissolved at the same temperature. 0.0321 mol of PMDA and 0.0214 mol of BPAF were added to the PDMS and TFMB-added solution at the same temperature, and the mixture was stirred for 3 hours and then at 80 ° C for 4 hours.

&Lt; Comparative Example 28 >

N-diethylacetamide (DEAc) (partition coefficient: 0.32) (164 g) was charged into a stirrer through which a nitrogen stream was flowing. The reactor was maintained at a temperature of 25 ° C and a double terminal amine-modified DPS-DMS (Diphenylsiloxane-dimethylsiloxane co- (Molecular weight: 1340 g / mol) and 0.0321 mol of TFMB (2,2'-bis (trifluoromethyl) benzidine) were added and dissolved at the same temperature. 0.0321 mol of PMDA and 0.0214 mol of 9,9'-bis (3,4-dicaroxyphenyl) fluorene dianhydride) were added to the PDMS and TFMB-added solution at the same temperature, and the mixture was stirred for 3 hours, Lt; / RTI &gt;

&Lt; Example 31 >

N-diethylacetamide (DEAc) (partition coefficient: 0.32) (143 g) was charged into a stirrer through which nitrogen flow was flowing, and then 0.0019 mol of a terminal amine-modified DPS-DMS (molecular weight: 5700 g / mol) And 0.0409 mol of TFMB (2,2'-bis (trifluoromethyl) benzidine) were dissolved at the same temperature.

0.0321 mol of PMDA and 0.0107 mol of 4,4'- (hexafluoroisopropylidene) diphthalic anhydride were added to the PDMS and TFMB-added solution at the same temperature, and the mixture was stirred for 3 hours and then at 80 DEG C for 4 hours.

&Lt; Example 32 >

N-diethylacetamide (DEAc) (partition coefficient: 0.32) (143 g) was charged into a stirrer through which nitrogen flow was flowing, and then 0.0021 mol of DPS-DMS (molecular weight: 5000 g / mol) And 0.0407 mol of TFMB (2,2'-bis (trifluoromethyl) benzidine) were dissolved at the same temperature.

0.0321 mol of PMDA and 0.0107 mol of 4,4'- (hexafluoroisopropylidene) diphthalic anhydride were added to the PDMS and TFMB-added solution at the same temperature, and the mixture was stirred for 3 hours and then at 80 DEG C for 4 hours.

&Lt; Example 33 >

N-diethylacetamide (DEAc) (partition coefficient: 0.32) (143 g) was charged into a stirrer through which nitrogen gas flow was passed. Then, 0.0024 mol of DPS-DMS (molecular weight: 4400 g / mol) And 0.0404 mol of TFMB (2,2'-bis (trifluoromethyl) benzidine) were dissolved at the same temperature.

0.0321 mol of PMDA and 0.0107 mol of 4,4'- (hexafluoroisopropylidene) diphthalic anhydride were added to the PDMS and TFMB-added solution at the same temperature, and the mixture was stirred for 3 hours and then at 80 DEG C for 4 hours.

&Lt; Comparative Example 29 &

N-diethylacetamide (DEAc) (partition coefficient: 0.32) (143 g) was charged into a stirrer through which nitrogen flow was flowing, and then 0.0075 mol of a terminal amine-modified DPS-DMS (molecular weight 1340 g / mol) And 0.0353 mol of TFMB (2,2'-bis (trifluoromethyl) benzidine) were dissolved at the same temperature.

0.0321 mol of PMDA and 0.0107 mol of 4,4'- (hexafluoroisopropylidene) diphthalic anhydride were added to the PDMS and TFMB-added solution at the same temperature, and the mixture was stirred for 3 hours and then at 80 DEG C for 4 hours.

<Experimental Example 2>

The polyimide precursor compositions prepared in Examples 28 to 33 and Comparative Examples 28 to 29 were spin-coated on glass substrates to a thickness of 9.5 to 11 탆. The glass substrate coated with the polyimide precursor composition was placed in an oven and heated at a rate of 2 占 폚 / min. While maintaining at 80 占 폚 for 15 minutes, 150 占 폚 for 30 minutes, 220 占 폚 for 30 minutes, and 400 占 폚 for 1 hour, The process was carried out. After completion of the curing process, the glass substrate was immersed in water, and the film formed on the glass substrate was peeled off and dried at 100 DEG C in an oven to prepare a polyimide film.

The yellow brightness (YI), haze, thickness direction retardation, CTE, glass transition temperature (Tg) and glass stress (Bow) of the polyimide film were measured and shown in Tables 7 and 8.

<Yellowness index (YI)>

Yellowness (YI) was measured with Color Eye 7000A.

<Haze>

Haze was measured by the method according to ASTM D1003 using Haze Meter HM-150.

<Thickness direction phase difference>

The thickness direction retardation (Rth) was measured using Axoscan. The thickness of the film was measured by cutting the film to a certain size. Then, the thickness was measured while correcting the retardation value in the C-plate direction in order to compensate the retardation value by measuring the phase difference with the Axoscan.

&Lt; Thermal expansion coefficient (CTE) and glass transition temperature (Tg) >

The film is prepared to have a size of 5 x 20 mm and the sample is loaded using an accessory. The actual measured film length was equal to 16 mm. The film was pulled up at a rate of 5 DEG C / min in a temperature range of 100 to 350 DEG C, and then heated at a cooling rate of 4 DEG C / min in a temperature range of 350 to 100 DEG C The change in the thermal expansion when cooled was measured by TMA (Q400, TA Corporation).

At this time, the inflection point shown in the temperature rising section in the first heating step was defined as Tg.

<Glass Stress>

The glass stress was expressed by the value of Bow and the measurement method is as follows.

A 10 cm x 10 cm glass was placed on a stress meter (FLX2320, manufactured by TENCOR), scanned with a laser, and the deviation (height) of the glass was measured at a distance of 4 cm between the left and right sides of a center portion of 8 cm Respectively.

<Cross-sectional Component Analysis>

Polyimide films prepared from the polyimide precursor compositions of Examples 28 and 29 were subjected to epoxy molding to produce TEM flakes. The results of the observation of the flakes with the STEM HAADF technique and the results of the EDS analysis of the cross-sections are shown in FIGS. 2 to 4.

TEM (FE-STEM, TITIAN G2 80-200 ChemiSTEM), and the analysis conditions were measured as follows.

- Acceleration voltage: 80 to 200 kV

- Resolution: point of resolution (240pm)

- Energy spread: 0.8Ev

Example 28 Example 29 Example 30 Comparative Example 28 DPS-DMS Mw 5700 5000 4400 1340 Organic solvent DEAc DEAc DEAc DEAc DPS-DMS content
(weight%) 20 20 20 20 PI molecular weight 59400 58300 52000 46000 Solid concentration
(weight%) 17.3 17.7 18.5 19.8 Viscosity (cps) 4800 4300 3650 2890 Thickness (μm) 9.6 9.9 10.1 10.1 YI 5.8 5.6 4.75 4.1 Haze <1 <1 <1 <1 Rth 185 190 195 220 CTE
(100 ~ 350 ° C, 1st cooling) 68.3 74.5 85 120 Tg (占 폚) 395 390 370 280 Real Bow (μm) -18 -18 -18 -30 Stess Mpa 28 30 34 55

Example 31 Example 32 Example 33 Comparative Example 29 DPS-DMS Mw 5700 5000 4400 1340 Organic solvent DEAc DEAc DEAc DEAc DPS-DMS content
(weight%) 30 30 30 30 PI molecular weight 61000 59300 56200 48500 Solid concentration
(weight%) 16.7 17.1 17.8 19.1 Viscosity (cps) 5050 4850 45200 3120 Thickness (μm) 9.8 10.0 9.9 10.2 YI 4.7 4.5 4.2 3.8 Haze <1 <1 <1 <1 Rth 200 198 197 210 CTE
(100 ~ 350 ° C, 1st cooling) 79.5 81.5 89.2 165 Tg (占 폚) 370 365 355 250 Real Bow (μm) -20 -22 -24 -38 Stess Mpa 31 34 37 60

As can be seen from Tables 7 and 8, the polyimide precursor compositions of Examples 28 to 33 have improved thermal properties such as glass transition temperature and CTE characteristics as well as haze characteristics by using DPS-DMS having a molecular weight of 4400 g / mol or more appear. On the other hand, in Comparative Examples 28 and 29, haze was improved by using DEAc. However, by using DPS-DMS having a low molecular weight, CTE was high and Tg was low. In Examples 28 to 30, as the molecular weight of DPS-DMS increases, the glass transition temperature of the polyimide film increases and the CTE decreases.

Figs. 2 and 3 show cross sections of the polyimides of Examples 28 and 29. Fig. In FIG. 2 and FIG. 3, it can be seen that the relatively bright region (black) and the relatively dark region (black) are uniformly distributed. In this case, (Fig. 2b, 3b) and point analysis through EDS mapping (Fig. 4).

The fact that the bright portion on the TEM image is evenly distributed on the polyimide means that the polyimide containing Si on the polyimide sample has undergone micro-phase separation because the portion including the PMS-DMS structure is poly Which means that it is co-continuous in the mid-matrix. Accordingly, the present invention can provide a polyimide having uniform transparency without being phase-separated in the polyimide matrix to lower the haze characteristic and obtain more transparent polyimide even in the case of PMS-DMS having a high molecular weight, Since the DMS structure is present in a continuous phase, the mechanical strength and stress relaxation effect of the polyimide can be improved more efficiently. From these characteristics, the composition according to the present invention can provide a flat polyimide film with reduced thermal and optical properties as well as a phenomenon in which the substrate is warped after coating-curing.

INDUSTRIAL APPLICABILITY The present invention can provide a polyimide film which is more colorless and excellent in heat resistance, by producing polyimide by polymerizing an organic solvent having a positive distribution coefficient (Log P) using a diamine containing a Si structure having a high molecular weight.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. something to do. It is therefore intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims (16)

A polyimide precursor prepared by using as a polymerization component a diamine having a molecular weight of 4000 g / mol or more and a tetracarboxylic dianhydride containing a diphenylsiloxane-dimethylsiloxane copolymer structure in a molecular structure and having a molecular weight of 4000 g / mol or more; And Log P is an organic solvent,
Wherein the diphenylsiloxane-dimethylsiloxane copolymer structure is distributed in a continuous phase in a polyimide structural matrix. delete The method according to claim 1,
And a diamine containing a diphenylsiloxane-dimethylsiloxane copolymer structure in an amount of 1 to 20 mol% based on the total diamine. The method according to claim 1,
Wherein the weight of the diamine containing the diphenylsiloxane-dimethylsiloxane copolymer structure is 20 to 50 wt% based on the total weight of the polyimide precursor composition. The method according to claim 1,
Wherein the tetracarboxylic dianhydride is at least one selected from among tetracarboxylic dianhydrides having a tetravalent organic group of the following general formulas (2a) to (2i) in the molecular structure:
(2a)

(2b)

[Chemical Formula 2c]

(2d)

[Formula 2e]

(2f)

[Chemical Formula 2g]

(2i)

In the above formulas (2a) to (2i), R11 to R24 each independently represent a halogen atom selected from the group consisting of -F, -Cl, -Br and -I, a hydroxyl group (-OH), a thiol group A nitro group (-NO ₂ ), a cyano group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy group having 1 to 4 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms,
A3 is an integer of 0 to 8; a4 and a5 are each independently an integer of 0 to 3; and a7 and a8 are each independently an integer of 0 to 3, and a1 is an integer of 0 to 2, a2 is an integer of 0 to 4, a3 is an integer of 0 to 8, A15 and a16 are each independently an integer of 0 to 4; a17 and a18 are each independently an integer of 0 to 4; and a15 and a15 are each independently an integer of 0 to 4, , a6, a9, a13, a14, a19 and a20 are each independently an integer of 0 to 3,
n is an integer of 1 to 3,
A ₁₁ to A ₁₆ each independently represent -O-, -CR'R "-, -C (= O) -, -C (═O) O-, -C (═O) NH-, -SO ₂ -, phenylene group, and combinations thereof, wherein R 'and R "are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms Lt; / RTI &gt; The method according to claim 1,
A diamine having a divalent organic group represented by the following formula (3) in a molecular structure in an amount of 80 to 99 mol% based on the total diamine content:
(3)

In Formula 3,
R ₃₁ and R ₃₂ each independently represent a halogen atom selected from the group consisting of -F, -Cl, -Br and -I, a hydroxyl group (-OH), a thiol group (-SH), a nitro group ₂ ), a cyano group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy group having 1 to 4 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 20 carbon atoms,
Q is a single bond, -O-, -CR'R "-, -C (= O) -, -C (= O) O-, -C (= O) NH-, -S-, -SO 2 - , Phenylene group and combinations thereof, wherein R 'and R "are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms will be. The method according to claim 1,
A polyimide comprising a tetracarboxylic dianhydride having a structure represented by the following formula (4) in an amount of 20 to 80 mol% in the total tetracarboxylic dianhydride:
[Chemical Formula 4]

The method according to claim 1,
Wherein the tetracarboxylic dianhydride of formula (5) is contained in an amount of 20 to 80 mol% in the total tetracarboxylic dianhydride:
[Chemical Formula 5]

In Formula 5,
Q ₁ and Q ₂ is a single bond, each independently, -O-, -C (= O) -, -C (= O) O-, -C (= O) NH-, -S-, -SO 2 - , Phenylene group, and combinations thereof. The method according to claim 1,
And a tetracarboxylic dianhydride of the following formula (4) and (5):
[Chemical Formula 4]

[Chemical Formula 5]

In Formula 5,
Q ₁ and Q ₂ is a single bond, each independently, -O-, -C (= O) -, -C (= O) O-, -C (= O) NH-, -S-, -SO 2 - , Phenylene group, and combinations thereof. The method according to claim 1,
Wherein the organic solvent in which Log P is positive is selected from the group consisting of N, N-diethylacetamide, DEAc, N, N-diethylformamide, (N-ethylpyrrolidone, NEP). A polyimide film made from the polyimide according to any one of claims 1 to 10. 12. The method of claim 11,
Wherein the polyimide film has a haze of 2 or less. 12. The method of claim 11,
Wherein the polyimide film has a glass transition temperature (Tg) of 350 DEG C or more. 12. The method of claim 11,
Wherein the polyimide film has a coefficient of thermal expansion (CTE) of 100 ppm / 占 폚 or less. A transparent polyimide substrate for an oxide TFT made of the polyimide according to any one of claims 1 and 3 to 10. A transparent polyimide substrate for LTPS made from the polyimide according to any one of claims 1 to 10.

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